Blockchain Papers

Stephen J. Morse

The editors of this journal have kindly requested me to comment on four very interesting empirical studies from the USA,1 England and Wales,2 Canada,3 and the Netherlands4 that have attempted to discover the extent to which and in what way neuroscientific evidence is used in criminal cases. Recent excitement about the potential legal implications of non-invasive brain imaging by fMRI motivates this work, excitement that has been generated since about 2000, when the explosion in studies of cognitive, affective, and social neuroscience began. Although some are cautious and even hostile to the possibility of such legal implications at present, others think neuroscience has immense potential to guide the law and, alas, some suffer from Brain Overclaim Syndrome.5 These studies begin to examine the reality of neuroscientific influence in criminal cases. All focus on appellate cases reported in various data bases for somewhat different periods in the range of years from 2000 to 2012 and all are admirably cautious about the methodological limitations of the study sample. None purports to be an accurate representation of the use of neuroscientific evidence throughout the criminal justice system and other methodological quibbles may be raised, such as the failure to use independent inter-rater reliability for characterizing the cases. All use a very expansive definition of neuroscience that includes techniques and data that long antedate the new neuroscience. At most, the data are suggestive. Nonetheless, the studies are interesting and innovative, and the authors are to be congratulated. The late, great baseball scientist, Yogi Berra, was apocryphally quoted as saying, ‘It's déjà vu all over again.’ That is precisely the reaction provoked by reading these studies. That is, the courts and, to a much lesser extent, the authors of these studies make the classic mistakes about the relevance of neuroscience and behavioral genetics to criminal cases that have bedeviled the reception of behavioral science in general and of psychiatry and psychology in particular. The overarching classic mistake is misunderstanding or uncritically accepting the validity of apparently relevant science and misunderstanding the relevance of the science to the specific criminal law criteria at issue, which are primarily acts and mental states. There are no brain or nervous system criteria in criminal law for any doctrine. In particular, courts too often do not understand the following. Metaphysical free will is not a criterion for any criminal law doctrine and it is not even foundational for criminal responsibility in general.6 Causation in general and brain causation in particular, even causation by abnormal variables, are not per se a mitigating or excusing condition and causation per se is not the equivalent of compulsion, which is an excusing condition. And, finally, people with the same diagnosis or condition are behaviorally heterogeneous and ultimately it is the behavior that is legally relevant, not the diagnosis. In one form or another, most of these cases exhibit these mistakes and confusions. It is no surprise that one of the authors, Professor Nita Farahany, characterizes the cases as follows: ‘That use [of neurobiological research in criminal law] continues to be haphazard, ad hoc, and often ill conceived.’7 After briefly canvasing the general findings of the studies, this comment will focus on why Professor Farahany's conclusion is correct and what can be done to rectify the problem. Not surprisingly, sentencing decisions were the most common context for the introduction of neuroscience evidence, but it was also used to resolve questions about the act doctrine, mens rea, affirmative defenses, such as legal insanity and, surprisingly, duress, and, also surprisingly, competence. Perhaps, the most striking finding is how infrequently the new neuroscience of functional imaging and related techniques is used. This varies across jurisdictions, but the large majority of cases involve the ‘old’ neurology or the old neuropsychology that uses classical structural imaging or behavioral methods to assess brain functioning associated with well-characterized neurological conditions, such as epilepsy and frontal lobe injuries or lesions. Such diagnostic methods are far more common than fMRI, and in the Dutch and Canadian samples, there is virtually no functional imaging evidence. It would be interesting to compare the current samples with similar samples from, say, 1980–2000. There should be little difference in the use of neuroscience as the current studies expansively defines it unless the new neuroscience has emboldened advocates to make claims based on the old neurology or neuropsychology that they would not otherwise have made. In sum, these studies suggest that the influence of the new neuroinvestigative techniques applied to individual cases for forensic assessment is quite modest. Even when inferences are drawn in individual cases using group data about the consequences of various neurological conditions, the studies used are often classic behavioral studies rather than neuroimaging investigations. Indeed, careful examination of the expanded case studies the papers present indicates that in most instances the neuroscientific evidence was far less important than the behavioral evidence and the former was used largely to buttress the latter. The neuroevidence was rarely dispositive and in the other cases it is impossible to know from these papers’ summaries of the case reports how influential the additive neuroevidence was. In a case well-known to US lawyers, Powell v Texas,8 the Supreme Court was asked to hold that, ‘a person may not be punished if the condition essential to constitute the defined crime is part of the pattern of his disease and is occasioned by a compulsion symptomatic of the disease.’9 In short, the Court was asked to adopt a constitutionally required defense of compulsion or ‘involuntariness’ based on the disease of chronic alcoholism. In response, writing for the plurality, Justice Marshall said, ‘The difficulty with this position…is that it goes much too far on the basis of too little knowledge.’10 This was a correct reflection of the state of knowledge.11 It is also true of the potential contributions of the new (and old) neuroscience to criminal law decision-making as I shall try to explain in what follows. The first question when considering the admissibility of scientific evidence, as always, is the degree to which the basis of the testimony has been established. It is no critique of contemporary neuroscience to note that it is working on one of the hardest problems in science, the relation of the brain to mind and action. We do not know how the brain enables the mind and action12 and the new neuroscience is a very young science using still relatively crude methods despite the astonishing advances. Most of what we know is correlational and coarse rather than causal and fine-grained.13 Perhaps, most important for legal purposes, replications are very rare, making it difficult to know what data are firmly established. Recent work has demonstrated that about a third of a sample of important findings in psychology failed to replicate.14 The behavioral neurosciences are less mature than psychology and healthy caution is warranted. For example, the apparently wide but not universal Dutch acceptance of a brain disease model of addiction that guides legal decision-making fails to confront the hard questions about the status of the science. Judges are not yet in a good position to evaluate neuroscience and may be either too critical or too uncritical.15 In what follows, however, I shall assume that the science is reasonably valid and that images in individual cases were properly acquired and evaluated. The ultimate guide to wisdom about the proper use of neuroscientific evidence is a keen understanding of legal relevance, which in turn requires an equally keen understanding of the legal question at issue. The question in any case, then, is how, precisely, does neuroscience evidence help decide whether an act or mental state criterion was present at the relevant time. Past mental state questions include the act doctrine, mens rea, legal insanity, and sentencing based on culpability. Present mental state questions include various criminal competencies and sentencing based on prediction of future dangerousness. No hand-waving about relevance is allowed. For example, a broken brain or a gene-environment interaction that raises the risk of antisocial behavior is not per se a mitigating or excusing condition. Such evidence is relevant only if it supports the presence of a genuine excusing or mitigating condition. Whatever rhetorical use an advocate may be able to make of neuroevidence is distinguishable from whether the evidence is really, as opposed to rhetorically, relevant. The chain of inference from the purely mechanical neurodata to the law's act and mental state criteria must be clear. Unless the neuroevidence can help answer these questions, it is not legally relevant, even if it is scientifically valid. Thus, if there is a disjunction between the subject's behavior and the neuroevidence, actions always speak louder than images, except perhaps in cases of malingering (although the science cannot at present reliably and validly identify malingerers). If the defendant's brain appears broken, but he is a rational agent, he is rational for legal purposes. If the brain appears normal, but the agent is clearly psychotic, the agent is not rational for legal purposes. For example, fetal alcohol syndrome (FAS) plays a large role in the Canadian cases (although not in the other samples), but the potentially legally relevant aspects of the disorder are the cognitive and rationality defects, which are behavioral signs, that sufferers demonstrate from an early age. Are the brains of FAS sufferers different from the brains of those without the disorder? Of course. This is just a necessary truth of biological materialism. If the behavior is markedly different, so will be the brain. Brain difference is not per se a mitigating or excusing condition, however. If a particular FAS sufferer is somehow sufficiently able rationally to regulate his behavior, then FAS is irrelevant to mitigation or excuse. Moreover, if a FAS sufferer exhibited lifelong cognitive defects, as many do, that sufferer is potentially excusable even if sophisticated neurotechniques cannot identify the brain pathology or brain difference. Adolescent responsibility furnishes another, similar example. We knew and the law recognized for centuries that adolescents are on average less rational than adults and we were certain about this long before diffusion tensor imaging demonstrated that adolescent and adult brains also differ biologically on average. If the neurotechniques were not able to demonstrate brain difference, would we conclude that adolescents are as rational as adults? Many of the cases in these studies fail to understand the relevance of the neuroevidence. Even if there is clear evidence of brain damage or a neurological disorder, it does not mean that the defendant did not act, lacked mens rea, was less culpable, is incompetent, or will be dangerous in the future. All the criteria depend on direct assessment of the offender's behavior. In a review published in 2013 that looked at every culpability, competence and prediction question in criminal law, Morse and Newsome concluded that with the exception of a few well-characterized medical disorders, present neuroscience was insufficiently advanced to help decide any legal question.16 Nothing has changed since. Neural markers are too insensitive to aid the diagnosis even of major mental disorder,17 and the notion that neuroscience can help determine whether a defendant knew right from wrong or the nature and quality of his act, for example, is ludicrous. There are few studies to date of the neural prediction of future offending or antisocial conduct and none is more than proof of concept or ready for practical use at present. The alleged relevance of neuroevidence to competence determinations, which occurs in many of the samples, is instructive but bewildering. Criminal competencies are behaviorally functional and again defined entirely in terms of mental states. Does the defendant understand the nature of the charges, can he rationally assist counsel, does he understand the consequence of a guilty plea, does he understand the nature of the penalty about to be imposed on him and why it is being imposed? These normative, mental criteria must all be evaluated behaviorally. Either the defendant can perform these tasks to the requisite degree or he cannot. These are continuum capacities, however, and it may be asked whether neuroscience can help with the gray area, indeterminate cases. The answer is, no, for various reasons. Any brain condition will have heterogeneous consequences. Some people with very broken brains have essentially normal mental functioning. But, cannot group data about people with this condition help us draw inferences at the margin. Once again, the answer is, no, in the present state of neuroscience as a result of the ‘clear cut’ problem. Behavioral neuroscientists are interested in the neural correlates and causes of various behavioral phenomena, such as schizophrenia, impulsivity, or memory defects. Valid studies begin with well-characterized behavioral phenomena to be investigated, but in these cases the behavior is clear and no neuroscience is necessary to distinguish them. Nonetheless, even in clear cases, there will be substantial overlap in the data between the comparison/experimental and control subjects, which is why neural markers are insufficiently sensitive to be used for diagnosing even severe mental disorders. Gray area phenomena are not studied because it is not clear that researchers can properly assign subjects to the comparison and control groups because the phenomenon is not well-characterized. If gray area cases were studied, the date overlap would be massive and thus unhelpful in distinguishing the cases. In behaviorally unclear cases in which the law needs help the most, neuroscience is least able to furnish it. Actions speak louder than images, EEG findings, or neuropsychological tests, behavioral genetics, or any of the other types of neuroevidence courts are confronted with. A critical reader will be repeatedly struck by how many of the expanded cases either used irrelevant or weak (or non-existent) neuroscience—eg to assess competence or whether a defendant suffered from a mental illness—or could have been fully resolved with more careful behavioral evaluation. Of course there can be conflict about the behavioral evidence, but because act and mental state questions must be resolved, it is the behavioral evidence that is doing the real work. And for the reasons given, neuroevidence will seldom be helpful in resolving the gray area cases in which most help is needed. Much is at stake in criminal cases and of course judges would like scientific help to resolve the vexing normative issues they must resolve, but, at present, turning to the neuroscience will do nothing more in most cases than to provide a rationalization for a result the judge wishes to reach on other grounds or to avoid responsibility for having to make the hard decision directly by relying on the expert. Is there a more optimistic story? Before Professor Farahany becomes methodologically cautious, she claims that neuroscience is already ‘entrenched’ in the US legal system. This is not an empirical statement. It is a normative characterization and the evidence seems to show quite the opposite, with the possible exception of capital punishment decisions. She also ends on the optimistic note of claiming that neuroscience ‘improved’ competency evaluations and reconsiderations of the role of punishment in society. But it is unclear how the former could possibly be true. Either the behavioral signs are reasonably obvious or neuroscience cannot help as a result of the clear-cut problem. It is also unclear what the evidence is for the latter because the proper role of punishment in society has been debated for centuries and how would one assess how neuroscience has ‘improved’ this debate. Professor Farahany also claims that the evidence is more ‘nuanced than previously believed’, but, with respect, her own case studies indicate a lack of nuanced understanding of relevance. She concludes that, ‘[n]eurobiological evidence has profound implications for some of the most significant decisions we make in law and policy’, but without a conceptual framework about legal relevance—and none of these empirical studies purports to or is required to provide one—it is difficult to know what those ‘profound implications’ are. Moreover, the current state of the science relevant to criminal law18 does not support the statement. Indeed, the optimism of the conclusion seems quite at odds with the earlier characterization of the reception of the evidence and her excellently sober account of the actual data, which in her sample and all the other samples exhibit the problems identified. Nonetheless, I share Professor Farahany's optimism, but more reservedly. If a proper framework for the relevance of neuroscience to law is established and if a cautious approach to the science is adopted, I think neuroscience can potentially help refine legal mental state categories, such as mens rea and mental disorder through a conceptual-empirical equilibrium in which legal categories guide neuroscientific investigation that in turn then help clarify the legal categories. Neuroscience might also help the fairness and efficiency of criminal law decision-making by increasing predictive accuracy. The criminal law already uses predictions for purposes of diversion, sentencing, parole, and the quasi-criminal commitment of some sexual offenders. We have already decided as a normative matter that predictions are acceptable. If neural variables make this practice more accurate at reasonably acceptable cost, that is an advance. Finally, in tandem with behavioral science, neuroscience might help us more accurately understand legally relevant human capacities, such as the capacity for rationality and for self-control, which would again improve legal policy, doctrine, and adjudication. But all such optimistic outcomes will depend on precise understanding of legal relevance and valid science. In conclusion, these four studies are, in my opinion, more interesting for what they teach us about how neuroscience evidence is used than about how much it is used. They are a guide to a better future if we draw the right conclusions from them. The emerging study of law and neuroscience owes a debt to the authors.

Mustafa Ally, Michael Gardiner, Michael Lane

Crypto-currencies like Bitcoins are relatively recent phenomena on the online Internet landscape and an emerging force in the financial sector. While not conforming to traditional institutional practices, they are gaining increasing acceptance as viable commercial currencies. In this conceptual paper we discuss the potential impact of digital currency technology on the Australian economy, including the (i) payments sector, (ii) retail sector, and (iii) banking sector; and explore potential ways in which Australia can take advantage of digital currency technology to establish itself as a market leader in this field. The emergence of this new and potentially disruptive technology provides both opportunities as well as risks. In order to support innovation and the needs of the growing Australian digital currency industry it is important to define digital currencies and examine the impact regulatory frameworks could have on the further adoption and diffusion of the technology.

Andrew J. Engel, D. Scott Kreiner, Milan P. Stojanovic

Recently, Friedly et al. published a study on the effectiveness of epidural injections of steroids (ESIs) for lumbar spinal stenosis (LSS) [1]. Because of its apparent implications for clinical practice, this study attracted comments both in the professional [2] and lay press [3]. However, the study prompts reflection on a number of issues that extend beyond the conventional appraisal of a study. Those issues pertain to how physicians think about a condition, how it should be treated, and how to best assess the effectiveness of that treatment. The following article addresses those issues in the interest of informing physicians about how contemporary practices are confounded by lack of diagnostic discipline, and how this makes the conduct of controlled trials complicated and, therefore, makes the results difficult to assess. The cardinal issues are the symptoms of LSS; the diagnosis of LSS; the rationale for treatment; the consequent appropriate selection of patients; the outcomes assessment, either in practice or in a study including the reporting of those outcomes; and the need for rigorous control of the technical performance of the therapeutic intervention. Each of these issues has a critical bearing on appraising not only the literature on LSS, but also on how physicians treat this condition in conventional practice. The literature is profuse with heterogeneity in symptomology related to LSS. While there is no consensus in the current literature on acceptable LSS symptoms, the most commonly quoted symptoms are neurogenic claudication, radicular pain, and low back pain (LBP). Additional symptoms commonly mentioned in literature were fatigue and loss of power in the legs, anesthesia, and a feeling of numbness in the sacral dermatomes. In an attempt to achieve consensus, Katz et al. in 1995 published symptoms most strongly associated with the diagnosis of LSS (likelihood ratio ≥ 2), which included advanced age, severe lower-extremity pain, and absence of pain when seated [4]. In a recent, randomized trial by Weinstein et al., Spine Patient Outcomes Research Trial (SPORT), enrollment criteria included LSS on cross-sectional imaging and symptoms of either neurogenic claudication or radicular pain [5]. Patients were randomized to surgery and non-operative treatment, with short-term results favoring surgery. However, similar benefits from surgery were noted in patients with and without neurogenic claudication. A subgroup analysis demonstrated that patients with predominant leg pain improved significantly more with surgery than predominant LBP patients [6]. Overall, neurogenic claudication is the most commonly mentioned symptom of LSS; although the North American Spine Society guidelines list back pain as the most common complaint with a prevalence of 95%, followed by claudication (91%), leg pain (71%), weakness (33%), and voiding disturbances (12%) [7]. Claudication was first described by Dejerine in association with syphilitic arteritis of the spinal cord [8]. Blau and Louge described six cases of intermittent claudication caused by protrusion of a lumbar disc [9]. A 1964 report of two cases of “intermittent claudication from compression of cauda equina” resolved by lumbar laminectomy by Brish et al. was published 3 years later [10]. The contemporary definition of neurogenic claudication includes decreased ability to walk and stand with discomfort that radiates beyond the spinal area into the buttocks and frequently into the thigh and lower leg; it is exacerbated by lumbar extension and improves with lumbar flexion [17]. If neurogenic claudication is considered a hallmark symptom of LSS, a recent review of seven randomized controlled trials (RCT) revealed that the actual presence of neurogenic claudication was used as eligibility criteria in only 71% of LSS studies. When neurogenic claudication was necessary for enrollment eligibility, its definition varied considerably across studies, including symptoms such as “fatigue or loss of sensation in the lower limbs aggravated by walking” or “sitting as a better position for symptom severity than standing or walking” [24]. Similar to the variability in defining neurogenic claudication, all studies in this review presented imaging findings consistent with LSS, but a detailed radiological definition of LSS was provided only 57% of the time. The emphasis on neurologic features in the original literature was consistent with the proposed pathology [17,19,11–13]. By definition LSS is a narrowing of the spinal canal; therefore, it is logical that pain and neurologic symptoms would be a result of compromise of the nerve roots contained within the canal. The same link is missing for back pain: The pathophysiology of such a mechanism has neither been explained, nor supported in the literature. All the experimental and clinical evidence points to back pain arising from sources other than the nerve roots, such as the intervertebral discs, the zygapophysial joints, the sacroiliac joint, or perhaps the back muscles. Until proven otherwise, it becomes more rational to infer that the back pain reported by patients with LSS arises from one or another of these structures, rather than being caused by compression or ischemia of the cauda equina. This has been demonstrated in a study of patients with radiographic LSS, where the actual source of the patient’s back pain was traced to the zygapophysial joints, which was then treated by medial branch radiofrequency neurotomy [14]. In contrast to low back pain, it seems theoretically plausible that patients with LSS could present with radicular pain. However, it is important to note the differences between radicular pain caused by disc protrusion and neurogenic claudication caused by spinal stenosis. Although both are similar in clinical presentation, they have significant differences in pathophysiology and natural history analogous to the example comparing exercise induced angina and myocardial infarction (although both present with pain and are due to the same underlying principles). These differences can affect treatment outcomes and for that reason it is important to exactly identify the symptomatology of LSS before selecting a treatment modality or designing an outcome study. Despite the fact that LSS has been recognized for over 50 years, there is lack of consistency in use of this nomenclature: whether LSS is a clinical entity, a radiologic observation, or a term describing an anatomical state of the lumbar spine [15]. Historically, the first comprehensive report of LSS by Verbiest in 1954 described seven cases of a clinical condition in which there were symptoms of compression of the caudal nerve roots on standing or walking, but not at rest [16]. In all cases myelography showed a block in the lumbar region and narrowing of the spinal canal was found during surgery. The author suggested that the narrowing was due to encroachment on the spinal canal by the articular processes and that decompression of the dural sheath may be followed by complete relief. An updated and more accurate anatomical definition of LSS proposes that central LSS may result from a decrease in the anteroposterior, transversal, or combined canal diameter secondary to loss of disc height with or without bulging of the intervertebral disc; and hypertrophy of the facet joints and the ligamentum flavum [5]. The same process can also lead to lateral recess and foraminal spinal stenosis. The pathophysiology of LSS has been attributed to mechanical compression, ischemia, or both, of the lumbosacral nerve roots due to narrowing of the lateral and central vertebral canals [17,18]. The likely mechanism of ischemia is mechanical compression leading to further pressure on the venules surrounding the nerve roots causing its engorgement leading to ischemic and inflammatory nerve impairment [6,19–21]. Despite the anatomical description of LSS, the fact that up to 21% of asymptomatic subjects have significant radiographic findings of LSS poses an obstacle in reaching a consensus on diagnostic criteria for LSS, and also raises questions regarding the pathophysiologic mechanisms [22–24]. These findings imply that even detailed radiographic criteria alone (as summarized by Steurer et al. [25]) do not establish that LSS is the cause of a patient’s symptoms. The actual cause would be additional pathologic change leading to symptoms. A similar mechanism exists in coronary artery disease. Patients with atherosclerotic plaques causing coronary artery narrowing can be asymptomatic, only have exercised-induced angina, only have non-pain symptoms such as shortness of breath, or they could even suffer from an acute myocardial infarction. If an author presented a study to the New England Journal of Medicine for a treatment of coronary artery disease, with inclusion criteria limited to the presence of atherosclerosis and shortness of breath, it is probable that the article would not be published. This is because the authors would have failed to exclude other common causes of shortness of breath such as chronic obstructive pulmonary disease, asthma, anemia, and even a pulmonary embolism. Even if the proposed treatment were effective for atherosclerosis, the study would only demonstrate a positive effect if the authors were lucky enough to enroll a large percentage of subjects with this disease versus those with another. Unfortunately this exact problem is endemic in spine research. Due to the lack of a clear diagnostic algorithm for patients with spine pathology, both clinical care and even highly publicized research studies suffer from the critical flaw of heterogeneity [26]. It seems that LSS might be promoted to a diagnosis only if the attributable symptoms, and the cause of those symptoms, are stipulated; all too often this is not done in the literature. Perhaps the reason is that the possible combinations are too diverse both for anatomical variations (central, lateral recess, foraminal, size of stenosis) and symptoms of LSS. It would be very cumbersome to stipulate all the variations. However, lack of discipline in this regard is not without significance for studying the outcomes of ESIs since certain combinations may provide evidence for the use of such treatment, but for others the evidence may be lacking. In order to establish a diagnosis, a consensus on diagnostic criteria, including a combination of objective radiographic anatomical findings and patient symptoms, needs to exist. An explicit rationale for the use of epidural steroids for LSS has rarely been stated. The analgesic mechanism of action of steroids has not been clearly explained and accepted. The most accepted theory is the role of steroids in suppressing inflammation. In the lumbar spine, the inflammatory mediators can be present in elevated concentrations in degenerative discs [27] and may contribute to sensitization of peripheral nociceptors via prostaglandins [28]. Alternatively, steroids have been shown to decrease the ectopic discharge in injured nerves and decrease nerve conduction in small fibers [29,30]. These theories form a foundation for the role of steroids in treatment of radicular pain, with or without radiculopathy, caused by acute lumbar disc herniation even without full scientific proof. As opposed to acute disc herniation, the evidence for the role of inflammation in LSS is sparse, and therefore provides a weaker rationale for use of epidural steroids. In vitro evidence exists that inflammation can increase ligamentum flavum hypertrophy [31–33], but no evidence exists that steroids or oral anti-inflammatory medications can address that inflammation. There is some evidence that inflammation is involved to some degree in nerve root pathology in LSS [10,34]. It is possible that some unknown mechanism of epidural steroids (or other substances injected into epidural space along with steroids) may have beneficial effect in patients suffering from spinal stenosis related pain. Future research may shed light on this. Until then, a sound scientific rationale for the use of epidural steroids is not robust. It is important to have some knowledge of the expected outcomes of the disease in the absence of treatment. In the case of Friedly et al., the authors demonstrate pain relief nearing 40% in pooled subjects at 6 weeks post-procedure. This improvement is substantially greater than the typically predicted placebo response [35–37]. Additionally, there are other studies showing responses following epidural injections in the treatment of lumbar stenosis [38–41]. In some spine conditions, such as herniated discs, patient improvements at 6 weeks following a procedure may be attributed to either the natural history of the disease or the intervention provided to the patient. In the case of lumbar stenosis, the known natural history of the disease is typically not improvement over time [42]. When designing a prospective trial, all variables that may affect the outcome should be accounted for in determining the appropriate study size. In the case of spinal stenosis, this should include procedural variables such as: medication utilized, dosage, and route of injection. It would also include patient variables that may affect the outcome including: degree of stenosis, severity of symptoms, and duration of symptoms. Although Friedly et al. should be commended for performing a large RCT on 400 subjects, it is unfortunate that these multiple independent variables were grouped and analyzed together. Patients with a variety of diagnoses and symptom severities were injected in an assortment of ways with a myriad of medications. It is highly likely that statisticians and researchers will utilize this dataset for future subgroup analyses of these variables. However, this dataset should be scrutinized closely as each of these subgroups may not have sufficient numbers to facilitate an appropriate independent analysis. Choosing a proper study design is the best way to answer the proposed clinical question. In general, RCTs are felt to provide the highest level of evidence. There are two types of RCTs available from which to choose. An explanatory study will test a treatment against a placebo or “sham” to determine efficacy of the treatment. A pragmatic RCT will test one treatment against another to determine which treatment is superior. Friedly et al. chose the question “Are epidural injections of steroids plus lidocaine better than lidocaine alone for reducing pain and improving function in patients with lumbar central canal spinal stenosis?,” thereby selecting a pragmatic RCT study design. While the use of high quality observational studies and pragmatic RCTs has been supported by the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) system [43], an explanatory RCT would be a preferred study design choice for large, multicenter trials. It would provide the highest level of evidence and better address the question of whether epidural steroids are an effective treatment for spinal stenosis. Some physicians believe that injecting lidocaine, as it relates to intermediate-term, or 6-week relief, is a placebo treatment. This argument is founded on the action of the medication and known duration of local anesthetic effects. However, there is certainly reason to question whether administration of any substance into the epidural space is a placebo treatment [44]. Therefore, in order to conduct a valid explanatory RCT a true placebo group is necessary. In study design, an investigator determines the desired patient population early on. Diagnostic inclusion and exclusion criteria must be clearly defined in order for the reader of the article to determine if the study population is relevant to his or her own practice. In determining whether or not a treatment is effective, the investigator must choose outcome measures to evaluate the effectiveness of the treatment. The ideal outcome measure will evaluate the direct impact the treatment has on the diagnosis. For example, when evaluating a medication for hyperglycemia, fasting blood sugar level is an ideal outcome measure. In the case of most spine procedures, outcome measures are typically related to the pain and dysfunction that the condition causes. To determine the effectiveness of treatment in this realm, we rely on patient-reported outcomes. These measures typically assess outcomes such as symptoms (e.g., pain, claudication), function (e.g., ability to walk, perform activities of daily living), health status, health-related quality of life, and satisfaction with treatment. The validity and reliability of outcome measures are an integral of an and selection is the degree to which a or other measure test and no change is or across or is the degree to which a measure it is to measure. measures need to be for the diagnosis being For the study of pain, the for pain and the for pain have been When studying back pain, other outcome have been and In the study of lumbar stenosis, the Claudication also to as the and have been The outcome measures have a significant impact on evaluating how effective a treatment For example, when evaluating a treatment for lumbar radicular pain, appropriate outcome measures would evaluate pain, for back and leg pain, and for However, in the case of lumbar stenosis back pain is not a defining of the condition, an investigator would typically choose an outcome measure to address the of this condition, neurogenic claudication. outcome measures are and include the no direct studies to on ESIs for lumbar spinal stenosis, including the Friedly et al. have used appropriate and outcome measures as the for this Friedly et al. a but not for spinal stenosis. Until outcomes measures are the between an effective treatment and may be difficult to In the it has been conventional to report group outcomes. This is a in the literature that can result in a of the true outcomes. (or rely on a pain to a A of is not frequently found in patients with Even if it is it is to be present a treatment. This is true if the treatment results in a of patients with complete or complete pain relief. on a treatment that results in only and is not only but also to an actual treatment response from any patient. The appropriate therefore, should be a The definition of may to the condition and can be defined by The most commonly used example is pain relief and of although studies very rigorous and definition of such as complete relief of pain with full of to and no use of other health care have been reported treatment pain with from efficacy of of steroids for the treatment of lumbar radicular by and by the American of The alone is not a certain percentage of patients may have in one that not that the same percentage of patients will have in another study or clinical practice. In that percentage can on how subjects were included in the study. In order to for these the should be The the and highest percentage of patients could In an observational if this the intervention likely has no In a pragmatic if the of the two treatment there is likely no in effectiveness between the two could be or of no to In an explanatory if the of the and likely caused the beneficial of the treatment. These of analysis need to be to the question of spinal stenosis. from ESIs in patients with spinal stenosis exist. et al. have demonstrated in an observational study that of patients can have complete pain relief with ESIs the not include patients from treatment. An observational study whether the improvement was caused by the by associated with the or if patients improved because of the natural While can be used as a secondary outcome analysis of on outcome measures should be the the studies of ESIs for spinal stenosis, including Friedly et al., not provide for the outcome It would also be to whether the treatment the need for other health such as surgery. While the in pain both as important a in surgery would be a more response to treatment. As with all studies, the full is ability to the outcomes to patients is limited and as these do not treatment for spinal stenosis. the current state of the evidence to the use of epidural injections in the treatment of patients with LSS, questions are and more research is even the most comprehensive study to clearly demonstrated that the of steroids in a population by a variety of provides no as to injecting local anesthetic alone into the epidural space for patients with LSS on imaging [1]. However, since this study was a study only the effectiveness of steroids over lidocaine, it be used to answer the question of whether are effective for LSS. This would a study. any trial that diagnostic treated patients with a variety of symptoms in a variety of and failed to report complete outcomes could not provide any As a multicenter trial, it provide an of as present clinical practice in the but it may not a test of the of epidural steroids for LSS. is that the outcomes from this randomized controlled trial, with its will be used to a treatment. with that one can be injections for a patient population with lumbar spinal stenosis on which to be how they are in clinical practice, do not have a treatment effect beyond that of The authors to for his and of the Spine for review and and and of the Spine for review and comments on the A also to and Spine Society for and with the of this

Alonso González, Alejandro Hevia

Yao et al. (A note on the feasibility of generalized universal composability. Theory and Applications of Models of Computation pp. 474–485, 2007; A note on the feasibility of generalised universal composability. Mathematical Structures in Computer Science , 19 (1), pp. 193–205) claimed a potential limitation on the class of protocols that could be securely implemented in the generalized universal composability (GUC) framework proposed by Canetti et al. (Universally composable security with global setup. Lecture Notes in Computer Science , pp. 61–85, 2007). Specifically, Yao et al. presented a concrete attack on a GUC Zero Knowledge (GUCZK) protocol, a natural adaptation Blum's ZK proof for Directed Hamiltonicity using the general GUC feasibility of Canetti et al. (Universally composable security with global setup. Lecture Notes in Computer Science , pp. 61–85, 2007). Interestingly, the attack was not analysed in the GUC model in Yao et al. (A note on the feasibility of generalised universal composability. Mathematical Structures in Computer Science 19 (1), pp. 193–205, 2009) but in the FUC model , a new UC-like framework proposed in the same work. Nonetheless, Yao et al. (A note on the feasibility of generalised universal composability. Mathematical Structures in Computer Science 19 (1), pp. 193–205, 2009) argued that, in light of this attack, GUC would lose its concurrent general composability and proof of knowledge properties. Concretely, they argue that GUC composability would now be with respect to some adversaries with limited access to external arbitrary protocols. In this work, we show that the claimed attack from Yao et al. is indeed harmless and does not contradict the security of the mentioned GUCZK protocol, thus restoring the general feasibility for GUC.

Arturo Vargas Bustamante

For more than three decades healthcare decentralization has been promoted in developing countries as a way of improving the financing and delivery of public healthcare. Decision autonomy under healthcare decentralization would determine the role and scope of responsibility of local authorities. Jalal Mohammed, Nicola North, and Toni Ashton analyze decision autonomy within decentralized services in Fiji. They conclude that the narrow decision space allowed to local entities might have limited the benefits of decentralization on users and providers. To discuss the costs and benefits of healthcare decentralization this paper uses the U-form and M-form typology to further illustrate the role of decision autonomy under healthcare decentralization. This paper argues that when evaluating healthcare decentralization, it is important to determine whether the benefits from decentralization are greater than its costs. The U-form and M-form framework is proposed as a useful typology to evaluate different types of institutional arrangements under healthcare decentralization. Under this model, the more decentralized organizational form (M-form) is superior if the benefits from flexibility exceed the costs of duplication and the more centralized organizational form (U-form) is superior if the savings from economies of scale outweigh the costly decision-making process from the center to the regions. Budgetary and financial autonomy and effective mechanisms to maintain local governments accountable for their spending behavior are key decision autonomy variables that could sway the cost-benefit analysis of healthcare decentralization.

Euripides Rizos

Bitcoin is the most important and well known form of digital currency. It is not produced or backed by any single entity. Its production takes place in a decentralised manner and its value derives only from the fact that there is a growing community that attributes value to it and chooses to transact using this innovative means of payment. However, its importance is increasing, especially in the field of e-commerce. The main aim of this article is to examine the consumer’s right of withdrawal, as it is regulated in the Consumer Rights Directive (Directive 2011/83/EU), in case of payments with bitcoins. More specifically, it is examined whether a consumer’s payment with bitcoins can be a hindrance to the consumer’s protection, with respect to the withdrawal right provided by the aforementioned Directive in cases of distance and off-premises contracts. Furthermore, the consequences of the exercise of the withdrawal right are examined, particularly with regards to reimbursement. The main concerns derive from the bitcoin’s disputed legal nature and its high value volatility. Keywords Bitcoin Consumer Rights Directive consumer’s right of withdrawal e-commerce digital currency

Dominic Wörner, Thomas von Bomhard, Yan-Peter Schreier, Dominik Bilgeri

The Bitcoin ecosystem has grown tremendously in recent years.While the main sectors of growth and venture capital funding have been infrastructure for the Bitcoin ecosystem itself as well as financial services, there is also a more recent evolution in sectors beyond financial services.We classify the venture-capital backed start up ecosystem accordingly and present its evolution over time.Thereby, we identify interesting sectors, i.e. digital assets, marketplaces, and notary services.Each sector is further subdivided, and six representative venture-backed start-up companies are presented in comprehensive case studies.We extract the core innovations and Bitcoin features on which these are based.Finally, we critically discuss their disruptive potential.

Emmanuelle Anceaume, Romaric Ludinard, Bruno Sericola

International audience

Ministry of Finance of the Russian Federation, Vadim Vasilyev

The current differentiation of levels of socio-economic development of regions of Russia actualizes the need to develop a comprehensive regional policy on reducing regional disparities. The article presents a comparative analysis of approaches to the management of territorial development of the adjustment period. It identified the dominant direction of regulation – smoothing interregional differentiation by forming growth points and increasing inter-regional integration. The emphasis shifted to the development of decentralized co-financing of regional programs providing an innovative, socially-oriented development of the territories by forming zones of advancing economic growth. The article describes the basic principles of the system of intergovernmental relations. It justified the role of intergovernmental transfers in the creation of conditions for the integration and alignment of differentiation of the Russian regions. An analysis of currently intergovernmental transfers in Russia as the basis of the federal financial policy in relation to the regions. An analysis of the peculiarities of these kinds of intergovernmental transfers as grants, subsidies, subventions from the federal budget to the budgets of the Russian Federation. Consideration of the basic kinds of intergovernmental transfers allowed to prove the primary problems of the current system of intergovernmental fiscal relations.

Ikuo Magaki, Moein Khazraee, Luis Vega Gutierrez, Michael Taylor

GPU and FPGA-based clouds have already demonstrated the promise of accelerating computing-intensive workloads with greatly improved power and performance. In this paper, we examine the design of ASIC Clouds, which are purpose-built datacenters comprised of large arrays of ASIC accelerators, whose purpose is to optimize the total cost of ownership (TCO) of large, high-volume chronic computations, which are becoming increasingly common as more and more services are built around the Cloud model. On the surface, the creation of ASIC clouds may seem highlyimprobable due to high NREs and the inflexibility of ASICs. Surprisingly, however, large-scale ASIC Clouds have already been deployed by a large number of commercial entities, to implement the distributed Bitcoin cryptocurrency system. We begin with a case study of Bitcoin mining ASIC Clouds, which are perhaps the largest ASIC Clouds to date. From there, we design three more ASIC Clouds, including a YouTube-style video transcoding ASIC Cloud, a Litecoin ASIC Cloud, and a Convolutional Neural Network ASIC Cloud and show 2-3 orders of magnitude better TCO versus CPU and GPU. Among our contributions, we present a methodology that given an accelerator design, derives Pareto-optimal ASIC Cloud Servers, by extracting data from place-and-routed circuits and computational fluid dynamic simulations, and then employing clever but brute-force search to find the best jointly-optimized ASIC, DRAM subsystem, motherboard, power delivery system, cooling system, operating voltage, and case design. Moreover, we show how data center parameters determine which of the many Pareto-optimal points is TCO-optimal. Finally we examine when it makes sense to build an ASIC Cloud, and examine the impact of ASIC NRE.

Novinaz Benita

This paper examines decentralisation and distribution of access to primary school in Indonesia. Data come from Indonesia National Socio Economic Survey 2014, and statistic reports from Ministry of education, Ministry Of Finance, and General Election Commision. Descriptive statistic is used to describe spatial distribution of decentralization in primary education system and distribution of primary education access. The results show there are districts disparities in decentralization of primary education system and primary education access especially between district within Java islands and Papua islands. The results highlight the need to improving decentralization performance to achieve universal primary education in Indonesia, particularly within districts outside Java islands. Improving bureaucracy capacity particularly teachers is important to improve decentralization performance in primary school access.

Niels Jørgen Mau Pedersen

This article aims at presenting trends in the state-local budget-cooperation system in Denmark, following the local government reform in 2007 and the fiscal rules in the budget law from 2012. The article investigates some of the characteristics of the development from 1980 until 2016. Evidence gives support to the hypothesis that the possibility for the municipalities’ organization to negotiate increasing expenditures has been narrowed, however accompanied by more liberal grant financing. The local government reform seems to have opened a window of opportunity for an elaborated system of collective and especially individual central government sanctions to strengthen the macroeconomic management of service expenditures of local governments. The identified trends in the Danish state-local relations may indicate that the decentralized model of local governments in Denmark is increasingly under pressure. However, the Danish municipal sector is still growing with respect to economic significance.

Z. Bakonyi, Balázs Muraközy

This study analyzes which types of firm-level shocks were associated with the centralization of strategic decision-making during the recession of 2008-09. We use a unique survey dataset of more than 14000 manufacturing firms from seven European countries which includes direct information on whether the firms centralized or decentralized their strategic decision-making process. Motivated by theoretical approaches claiming that organizations under considerable stress are more likely to centralize, we use multinomial logit models to test whether firms facing a larger fall in turnover, employment, investment or having to postpone their innovations were more likely to change their decision-making process. We find evidence that employment change and postponing innovations are indeed associated with centralization even when we control for ownership, group structure, financing, management, and strategy.

Gulrukh Zaidi

No abstract is available for this record.

Daresema, Abenet

Decentralized service delivery refers to the mode in which service delivery is done through delegation and devolution of power from center to local governments whereby efficiency and effectiveness are likely to be achieved. The purpose of this study was to assess the improvements in education and health services delivery in Yeka sub city of Addis Ababa city government. To realize the purpose of the study, case study research method was conducted. The study is qualitative whereby simple quantitative tools were employed so as to complement the qualitative narrations. The study primarily utilized secondary data obtained, from policy documents, constitution, proclamations, intervention plans and performance reports, etc. The study was supported with primary data obtained through interviews and questionnaires. The data results revealed that there is achievement in health and education service delivery as well as there are gaps in the services delivered. The findings of the study revealed that various functions of education and health services have been devolved to the lowest tier of government. The study has indicated that there are multiple bodies established at lower levels of government to support school and health centers activities. As a result, the services provided have expanded; there is now an increased availability and accessibility of the services in both education and health. The study also observed constraints; the constraints consider human resource, finance and facilities . Key Words concepts: service delivery, education & health, decentralization

Dan McGinn, David Birch, David Akroyd, Miguel Molina-Solana · 6 authors

This work presents a systemic top-down visualization of Bitcoin transaction activity to explore dynamically generated patterns of algorithmic behavior. Bitcoin dominates the cryptocurrency markets and presents researchers with a rich source of real-time transactional data. The pseudonymous yet public nature of the data presents opportunities for the discovery of human and algorithmic behavioral patterns of interest to many parties such as financial regulators, protocol designers, and security analysts. However, retaining visual fidelity to the underlying data to retain a fuller understanding of activity within the network remains challenging, particularly in real time. We expose an effective force-directed graph visualization employed in our large-scale data observation facility to accelerate this data exploration and derive useful insight among domain experts and the general public alike. The high-fidelity visualizations demonstrated in this article allowed for collaborative discovery of unexpected high frequency transaction patterns, including automated laundering operations, and the evolution of multiple distinct algorithmic denial of service attacks on the Bitcoin network.

Ethan Buchman

Tendermint is a new protocol for ordering events in a distributed network under adversarial conditions. More commonly known as consensus or atomic broadcast, the problem has attracted significant attention recently due to the widespread success of digital currencies, such as Bitcoin and Ethereum, which successfully solve the problem in public settings without a central authority. Tendermint modernizes classic academic work on the subject to provide a secure consensus protocol with accountability guarantees, as well as an interface for building arbitrary applications above the consensus. Tendermint is high performance, achieving thousands of transactions per second on dozens of nodes distributed around the globe, with latencies of about one second, and performance degrading moderately in the face of adversarial attacks.

Yonatan Sompolinsky, Aviv Zohar

We revisit the fundamental question of Bitcoin's security against double spending attacks. While previous work has bounded the probability that a transaction is reversed, we show that no such guarantee can be effectively given if the attacker can choose when to launch the attack. Other approaches that bound the cost of an attack have erred in considering only limited attack scenarios, and in fact it is easy to show that attacks may not cost the attacker at all. We therefore provide a different interpretation of the results presented in previous papers and correct them in several ways. We provide different notions of the security of transactions that provide guarantees to different classes of defenders: merchants who regularly receive payments, miners, and recipients of large one-time payments. We additionally consider an attack that can be launched against lightweight clients, and show that these are less secure than their full node counterparts and provide the right strategy for defenders in this case as well. Our results, overall, improve the understanding of Bitcoin's security guarantees and provide correct bounds for those wishing to safely accept transactions.

Steffen Eckhard

Focusing on German and EU support with assisting local police reform in the context of international peacebuilding in Afghanistan since 2001, this article scrutinizes whether the two organizations exhibit a strategic fit between their policy mandate and the design of management tasks. Comparison of two vastly different institutions - Germany, a nation state, and the EU, an international organization - sheds analytical light on the way different bodies manage a similar policy problem. By way of empirical research, the paper finds that incremental planning, decentralization and autonomous leadership enhance performance as they enable peacebuilders to respond flexibly to the dynamic challenges they face in the field. This was the case with Germany, however not with the EU. No strategic fit prevailed on evaluation. Strategy review either failed (Germany) or had unintended consequences (EU).

Lawrence J. Trautman

The American corporate graveyard is littered with prior darlings of Wall Street and pillars of the New York Stock Exchange, such as Kodak and Polaroid (both photography pioneers). More recently, other businesses and entire industries that were once household names have similarly experienced plummeting demand: pay telephone manufacturers; travel agencies; wrist watch manufacturers; print news media such as newspapers and magazines; and many traditional brick and mortar retailers (replaced by Amazon). The common characteristic is that all of these businesses have become completely or substantially obsolete due to digitized technology.Now, the equivalent disruptive technological revolution in financial services is underway. During recent years, rapid technological advances have resulted in a sea change to the way most of the world conducts and regulates financial services. While the implications are vast and the ultimate ramifications are largely unknown at this time, this article: examines the brief but important history of virtual currencies in general; considers the impact of Bitcoin in particular; and explores the promise for widespread application of Bitcoin’s underlying blockchain technological platform to the financial services industry.This brief article proceeds in five parts, as follows. First, there is a discussion of disruptive changes taking place in financial services. Second, the article briefly explores virtual currencies and the genesis of Bitcoin. Third, there is an explanation of blockchain technology - what it is and why it is important. Fourth, the article discusses recent developments that provide a validation of blockchain application to financial services markets. Finally, there is a brief review of regulatory challenges to the adoption of this new technology. A purpose of this article is to enhance the reader’s understanding of the promises and challenges faced by financial service providers due to these rapid advances in technology.

Benoît Libert, Fabrice Mouhartem, Thomas Peters, Moti Yung

Digital signatures are perhaps the most important base for authentication and trust relationships in large scale systems. More specifically, various applications of signatures provide privacy and anonymity preserving mechanisms and protocols, and these, in turn, are becoming critical (due to the recently recognized need to protect individuals according to national rules and regulations). A specific type of signatures called "signatures with efficient protocols", as introduced by Camenisch and Lysyanskaya (CL), efficiently accommodates various basic protocols and extensions like zero-knowledge proofs, signing committed messages, or re-randomizability. These are, in fact, typical operations associated with signatures used in typical anonymity and privacy-preserving scenarios.

Sergi Delgado-Segura, Cristian Tanas, Jordi Herrera‐Joancomartí

In Mobile Crowd Sensing (MCS), the power of the crowd, jointly with the sensing capabilities of the smartphones they wear, provides a new paradigm for data sensing. Scenarios involving user behavior or those that rely on user mobility are examples where standard sensor networks may not be suitable, and MCS provides an interesting solution. However, including human participation in sensing tasks presents numerous and unique research challenges. In this paper, we analyze three of the most important: user participation, data sensing quality and user anonymity. We tackle the three as a whole, since all of them are strongly correlated. As a result, we present PaySense, a general framework that incentivizes user participation and provides a mechanism to validate the quality of collected data based on the users' reputation. All such features are performed in a privacy-preserving way by using the Bitcoin cryptocurrency. Rather than a theoretical one, our framework has been implemented, and it is ready to be deployed and complement any existing MCS system.

Nicolas Gensollen, Vincent Gauthier, Monique Becker, Michel Marot

In the context of the smart grid, we propose in this paper an algorithm that forms coalitions of agents, called prosumers, that both produce and consume. It is designed to be used by aggregators that aim at selling aggregated surplus of production of the prosumers they control. We rely on real weather data sampled across stations of a given territory in order to simulate realistic production and consumption patterns for each prosumer. This enables us to capture geographical correlations among the agents while preserving the diversity due to different behaviors. As aggregators are bound to the market operator by a contract, they seek to maximize their offer while minimizing their risk. The proposed graph-based algorithm takes the underlying correlation structure of the agents into account and outputs coalitions with both high productivity and low variability. We show that the resulting diversified coalitions are able to generate higher benefits on a constrained energy market, and are more resilient to random failures of the agents.

Maria Apostolaki, Aviv Zohar, Laurent Vanbever

Bitcoin is without a doubt the most successful cryptocurrency in circulation today, making it an extremely valuable target for attackers. Indeed, many studies have highlighted ways to compromise one or several Bitcoin nodes. In this paper, we take a different perspective and study the effect of large-scale network-level attacks such as the ones that may be launched by Autonomous Systems (ASes). We show that attacks that are commonly believed to be hard, such as isolating 50% of the mining power, are actually within the reach of anyone with access to a BGP-enabled network and hijacking less than 900 prefixes. Once on path, AS-level adversaries can then partition the Bitcoin network or delay block propagation significantly. The key factors that enable these attacks are the extreme centralization of Bitcoin, both from a routing and a mining perspective, along with the fact that Bitcoin messages are sent unencrypted, without integrity guarantees. We demonstrate the feasibility of large-scale attacks in practice against the deployed Bitcoin software and quantify their disruptive network-wide impact. The potential damage to Bitcoin is severe. By isolating a part of the network or delaying the propagation of blocks, network-level attackers can cause a significant amount of mining power to be wasted, leading to revenue losses and enabling a wide range of attacks such as double spending. We provide several suggestions on approaches to mitigate such attacks employing both short-term and long-term measures.