Blockchain Papers

Dilek Teker, Suat Teker, Esin Demirel

Purpose- The primary purpose of this study is to model Bitcoin price volatility and forecast its future price returns using advanced econometric models such as ARCH and GARCH. The study aims to enhance risk management strategies and support informed investment decisions by addressing the time-varying nature of Bitcoin’s volatility. The research explores the persistence of volatility shocks and the clustering of price movements to provide insights into market dynamics. Methodology- This research examines daily Bitcoin closing prices over the period from January 2020 to October 2024. The data was preprocessed to ensure reliability, including applying logarithmic transformations to standardize the data and eliminate trends. Stationarity tests, such as the Augmented Dickey-Fuller (ADF), Phillips-Perron (PP), and KPSS tests, were conducted to confirm the series' stationarity. The ARCH-LM test was utilized to detect volatility clustering which is essential for validating the use of ARCH and GARCH models. Following this, ARIMA models were employed to define mean equations and GARCH models were used to estimate conditional variance and capture volatility dynamics. The dataset was split into training and validation subsets with data from July to October 2024 reserved for validation. Findings- The findings demonstrate that Bitcoin’s price movements exhibit significant volatility clustering and persistence of shocks which are key characteristics effectively captured by ARCH and GARCH models. These models provide valuable insights into the volatility patterns of Bitcoin, supporting their application in cryptocurrency analysis. Despite their robustness, the models face limitations in precise return forecasting during highly volatile periods, suggesting the need for further refinement or integration with advanced approaches. Conclusion- The research concludes that ARCH and GARCH models are effective tools for understanding and forecasting Bitcoin’s volatility. The study underscores the importance of acknowledging volatility persistence and clustering effects when analyzing cryptocurrency price behavior. However, it also highlights areas for improvement in econometric modelling by including the exploration of hybrid models and the integration of macroeconomic factors to enhance forecasting accuracy. Keywords: Bitcoin, ARCH models, GARCH Models, forecasting, ARIMA models JEL Codes: C58, G10, G12

Mike McKiernan

From an opening on the right, pallid hazy sunshine filters through into the dark interior of a high-roofed shed. Two young boys boisterously attack small lumps of grey rock (lead ore) with flat-headed, short-handled, ‘bucking’ hammers, whilst their older colleague in a brown brimmed hat and blue coat feeds their feverish fun by raking rocks down a sloping bench towards them. At the other side of the shed, a young man sedately tips a barrow-load of pounded ore onto the rough earth floor for his mate with a long-handled spade to shovel carefully into the adjacent washing tank. Both men wear frock coats, knee-length breeches, stockings, shoes, leather aprons and neckerchiefs. One has a hat—a sign of seniority? They wear no masks or gloves. In the background at a safe distance from the dust and grime, an elegantly dressed couple, classically posed, are accompanied by a bare-headed man, who points out the mischievous children hard at work. He may be a factory employee but the absence of a hat and the modesty of his dress infer a position too junior to escort such noble visitors. The object in his right hand might be a ledger or possibly a sketchbook. Perhaps he’s the artist, David Allan, who is known to have accompanied the Earl and Countess of Hopetoun on a visit to the Leadhills mineworks [ 1 ]. On the right, the rolling Lowther Hills confirm the rural setting, whilst the left reveals smoking chimneys and a burgeoning industrial landscape. The picture (oil on canvas 28×58cm) is from a set of four paintings commissioned by the Earl. The others are Washing the Ore , Smelting the Ore and Weighing the Lead Bars [ 2 ]. Allan, perhaps mindful of his patron’s goodwill and personal kindness [ 3 ], has romanticized the work scenes emphasizing the outdoor settings and portraying the hazardous employment as graceful, even playful [ 4 ]. In contrast to other critical descriptions of the mine’s working conditions [ 5 , 6 ], Allan ‘promotes industry in an acceptably genteel and sanitised way’ [ 4 ]. Yet Leadhills was a model workplace with a chaplain, schoolmaster, surgeon, a subscription library, charitable funds and pensions for sick and aged workers [ 7 ]. The four paintings were probably hung on the walls of Hopetoun Estates’ administrative HQ, Moffat House, which John Adam built for the Earl in 1767 in the fashionable spa town of Moffat [ 8 ]. David Allan was born in Alloa (1744) to father David, the port’s ‘Shoremaster’, and mother Janet who died a few days after his birth. He was educated at the local school and began drawing (chalk figures on the kitchen floor) during a forced convalescence from leg burns which kept him at home [ 3 ]. Aged 11 his father sent him to the Foulis Academy of Painting and Engraving, Glasgow on a 7 year apprenticeship. There he attracted the attention of several wealthy patrons including Lord Cathcart, who sponsored his further studies in Italy, where he stayed for 11 years. He left Rome for London in 1777 but poor health and lack of success drove him back to Scotland (1779) [ 9 ]. He settled in Edinburgh and began to paint small-scale conversation pieces and family portraits. During his stays in Rome and Naples, he had drawn many genre pictures and now he returned to these themes. His images of Scottish domestic and rural life embraced numerous trades and occupations—fishwives, lace-women, coal merchants, chimney sweeps and lead workers [ 9 ]. He also illustrated books including manuscripts by Robbie Burns, famously Tam o’ Shanter and The Cotter’s Saturday Night , and was appointed Master and Director of the Trustees’ Academy of Arts (1786) [ 9 ]. He died in Edinburgh (1796) and was buried in the city’s Old Calton Cemetery. Shy and self-conscious, but much admired for his genial humanity ‘Honest Allan’ was welcomed into the homes of rich and poor alike. In the 18th century art world, he ‘stood alone as the delineator of Scottish life’ [ 3 ]. Lead Mining at Leadhills, the delivery and sorting of the lead (oil on canvas)© Private Collection/Bridgeman Images. Although lead is widely distributed in Scotland, lead mining has always been a relatively small industry. There were workings at ‘leidhoillis’ in the 16th century and mining was well established by 1638. Output peaked around 1810 but eventually petered out (1928) [ 7 ]. Across the UK in 2014/15, there were 6319 lead workers (95% males) under medical surveillance and 19 were suspended due to excess blood lead levels [ 10 ]. An ‘In-Depth Review’ of lead toxicity in this journal argued for a thorough overhaul of these regulations to improve the ‘margin of safety between current occupational blood lead suspension limits and subclinical effects’ [ 11 ]. At Leadhills, miners no longer need protecting from ‘mill-reek’ (lead poisoning) but their 275-year-old Library continues to care for the local community [ 12 ]—Scottish enlightenment out of dark saturnine ashes.

Pagán Jiménez, JR, Oliver, JR

This chapter discusses the preliminary results derived from the analysis of 15 starch residue samples obtained from seven ground stone tools recovered from Los Muertos Cave (SR-1) and Vega de Nelo Vargas (Utu-27) sites' both located in the karst mountain region of northwestern Puerto Rico (Figure 11.1). This study provides new data that contribute to a better understanding of the nature of the agrarian economy of ancient Puerto Rico' one of the main objectives set forth in the Utuado- Caguana Archaeological Project' codirected by Oliver and Rivera Fontán (see Oliver 1998' 2005; Oliver et al. 1999). The time frame pertinent to this study is bracketed between a.d. 680 and a.d. 1450' covering Periods IIIa-b (early to late Ostiones) and IVa (Capá)' if one follows the regional chronology devised by Rouse (1992). Period IIIb (ca. a.d. 900- 1200/1300) is a momentous time' as it was when inequality and social complexity seem to have emerged in tandem with "monumental" architecture in the form of sites with multiple plaza and ball court precincts (Curet 2005:22-26' 90-91; Curet and Oliver 1998; Siegel 1999). By Period IVa (ca. a.d. 1250/1300-1500) complex polities' with varying degrees of centralization and hierarchical (and perhaps also heterarchical) organization' dominated the political scenario of ancient Puerto Rico' although not all polities in the island were necessarily subject to a paramount chief' and may have maintained a certain degree of decentralization and political autonomy (see Oliver 2003). Earle and Johnson (2000:257-258) and Earle (1991:1-15)' among others' have argued that the political economy of chiefdoms and states were financed by exercising political control over staple crops (staple finance) and/ or over material wealth of various kinds (wealth fi nance). Earle (1997:70-75) remarked that staple crops seem to play a larger role than wealth in financing chiefdoms than in states. For the historic Taíno' Moscoso (1986:414-432) compiled data from the early Spanish colonial documents that suggest that paramount caciques (chiefs) exhibited direct control over vast conucos' or plantations' cultivated principally with yuca' or manioc (Manihot esculenta)' and ajes' or sweet potatoes (Ipomoea batatas)' with other crops playing less important roles. Questions about the emergence of elites (caciques) and the nature of their political economy' however' are diffi cult to address given that the remains of crops from pre- Columbian archaeological contexts are few and far between despite all the recent advances (De France and Newsom 2005; Newsom and Wing 2004). The signifi cance of most of the identifi ed plant (and animal) species are still largely discussed at a coarse level of resolution (subseries and series) with the consequence that understanding what is going on at the levels of household and local community and discrete social groups remains vague. It is in this context that the foregoing starch residue analysis is an initial effort toward gaining new insights on the ancient agrarian economies of the Caribbean. The preliminary data emerging from this study suggest that the phyto- cultural dynamics of northwestern Puerto Rico do not neatly conform to the widely accepted' conventional views on the nature of the pre- Columbian agricultural economies of the Caribbean. The evidence points to different agricultural production scenarios that coexisted in the intra- And interisland contexts. © 2008 by The University of Alabama Press. All rights reserved.