Diversification Across Mining Pools: Optimal Mining Strategies under PoW

Mining is a central operation of all proof-of-work (PoW) based cryptocurrencies. The vast majority of miners today participate in "mining pools" instead of "solo mining" in order to lower risk and achieve a more steady income. However, this rise of participation in mining pools negatively affects the decentralization levels of most cryptocurrencies. In this work, we look into mining pools from the point of view of a miner: We present an analytical model and implement a computational tool that allows miners to optimally distribute their computational power over multiple pools and PoW cryptocurrencies (i.e. build a mining portfolio), taking into account their risk aversion levels. Our tool allows miners to maximize their risk-adjusted earnings by diversifying across multiple mining pools which enhances PoW decentralization. Finally, we run an experiment in Bitcoin historical data and demonstrate that a miner diversifying over multiple pools, as instructed by our model/tool, receives a higher overall Sharpe ratio (i.e. average excess reward over its standard deviation/volatility).Comment: 13 pages, 16 figures. Presented at WEIS 201

The incidence of congenital hypothyroidism (CH) in Guangxi, China and the predictors of permanent and transient CH

Background: The incidence of congenital hypothyroidism (CH) differs significantly among different ethnicities and regions, and early differentiation of transient CH is important to avoid unnecessary prolonged treatment with L-T4. Objective: To investigate the incidence of CH based on the newborn screening program in Guangxi Zhuang Autonomous Region, China, and to analyze the predictors that might allow for an early differentiation between permanent (P) and transient (T) CH. Design and methods Data from newborn screening program over a seven-year period (January 2009 to January 2016) at Guangxi Maternal and Child Health Hospital are analyzed. Blood samples were collected on filter paper between 3 and 7 days after birth, and TSH level was measured by time-resolved fluorescence assay. Individuals with increased TSH (TSH ≥ 8 IU/L) levels detected by newborn screening were recalled for further evaluation. Serum TSH, FT3 and FT4 were determined by electrochemiluminescence assay using venous blood samples. Diagnosis of CH is based on elevated TSH levels (>10 IU/L) and decreased FT4 levels (30 μg/day) has the highest predictive value for PCH. Earlier differentiation of PCH and TCH helps to determine appropriate treatment course

Mutation screening of the SLC26A4 gene in a cohort of 192 Chinese patients with congenital hypothyroidism

ABSTRACT Objective: Pendred syndrome (PS) is an autosomal recessive disorder characterised by sensorineural hearing loss and thyroid dyshormonogenesis. It is caused by biallelic mutations in the SLC26A4 gene encoding for pendrin. Hypothyroidism in PS can be present from birth and therefore diagnosed by neonatal screening. The aim of this study was to examine the SLC26A4 mutation spectrum and prevalence among congenital hypothyroidism (CH) patients in the Guangxi Zhuang Autonomous Region of China and to establish how frequently PS causes hearing impairment in our patients with CH. Subjects and methods: Blood samples were collected from 192 CH patients in Guangxi Zhuang Autonomous Region, China, and genomic DNA was extracted from peripheral blood leukocytes. All exons of the SLC26A4 gene together with their exon-intron boundaries were screened by nextgeneration sequencing. Patients with SLC26A4 mutations underwent a complete audiological evaluation including otoscopic examination, audiometry and morphological evaluation of the inner ear. Results: Next generation sequencing analysis of SLC26A4 in 192 CH patients revealed five different heterozygous variations in eight individuals (8/192, 4%). The prevalence of SLC26A4 mutations was 4% among studied Chinese CH. Three of the eight were diagnosed as enlargement of the vestibular aqueduct (EVA), no PS were found in our 192 CH patients. The mutations included one novel missense variant p.P469S, as well as four known missense variants, namely p.V233L, p.M147I, p.V609G and p.D661E. Of the eight patients identified with SLC26A4 variations in our study, seven patients showed normal size/location of thyroid gland, and one patients showed a decreased size one. Conclusions: The prevalence of SLC26A4 pathogenic variants was 4% among studied Chinese patients with CH. Our study expanded the SLC26A4 mutation spectrum, provided the best estimation of SLC26A4 mutation rate for Chinese CH patients and indicated the rarity of PS as a cause of CH. Arch Endocrinol Metab. 2016;60(4):323-

Mutation screening of the SLC26A4 gene in a cohort of 192 Chinese patients with congenital hypothyroidism

ABSTRACT Objective: Pendred syndrome (PS) is an autosomal recessive disorder characterised by sensorineural hearing loss and thyroid dyshormonogenesis. It is caused by biallelic mutations in the SLC26A4 gene encoding for pendrin. Hypothyroidism in PS can be present from birth and therefore diagnosed by neonatal screening. The aim of this study was to examine the SLC26A4 mutation spectrum and prevalence among congenital hypothyroidism (CH) patients in the Guangxi Zhuang Autonomous Region of China and to establish how frequently PS causes hearing impairment in our patients with CH. Subjects and methods: Blood samples were collected from 192 CH patients in Guangxi Zhuang Autonomous Region, China, and genomic DNA was extracted from peripheral blood leukocytes. All exons of the SLC26A4 gene together with their exon-intron boundaries were screened by next-generation sequencing. Patients with SLC26A4 mutations underwent a complete audiological evaluation including otoscopic examination, audiometry and morphological evaluation of the inner ear. Results: Next generation sequencing analysis of SLC26A4 in 192 CH patients revealed five different heterozygous variations in eight individuals (8/192, 4%). The prevalence of SLC26A4 mutations was 4% among studied Chinese CH. Three of the eight were diagnosed as enlargement of the vestibular aqueduct (EVA), no PS were found in our 192 CH patients. The mutations included one novel missense variant p.P469S, as well as four known missense variants, namely p.V233L, p.M147I, p.V609G and p.D661E. Of the eight patients identified with SLC26A4 variations in our study, seven patients showed normal size/location of thyroid gland, and one patients showed a decreased size one. Conclusions: The prevalence of SLC26A4 pathogenic variants was 4% among studied Chinese patients with CH. Our study expanded the SLC26A4 mutation spectrum, provided the best estimation of SLC26A4 mutation rate for Chinese CH patients and indicated the rarity of PS as a cause of CH

The Role of Information in Financial Markets, Security Design, and Theory of the Firm

My dissertation studies the role information plays in various financial and economic settings. My first chapter investigates how stock price corresponds to public information in after-hours trading. Almost all U.S. firms now announce earnings outside of regular trading hours. This paper studies how stock prices incorporate information in after-hours trading. I find slow prices adjustment accompanied by significant trading volume. During 2002-2012, 5,881 rule-based trading opportunities generate an average return of 1.53% within four hours. After costs (assessed by a trading experiment), an investor who properly exploits the slow adjustment beats the market by 11.5% per year. Analyzing the use of intermarket sweep order (ISO), a new order type launched under Regulation National Market System (Reg NMS), I link the slow price adjustment to investor trading behavior. My second chapter investigates how firms endogenously arise out of a marketeconomy in the presence of dispersed private information. It is well known that in a rational expectation equilibrium market price could empower individuals with their collective wisdom by coordinating actions guided by dispersed private information. I show that simple profit-sharing contracts replicates such coordination effect. Whenever rational expectation is imperfect due to noise or the lack of a liquid market, individuals always have incentives to create a partnership among themselves. Optimal profit-sharing within such a partnership replicates the effect of direct communication but without actually incurring communication. This insight sheds new light on the nature of the firm: firms endogenously emerge as an institutional innovation to complete the market under dispersed private information. I discuss several implications of this new perspective on general corporate finance topics. My third chapter studies optimal crowdfunding security design to harness investors’ collective wisdom. The notion that a population’s collective wisdom dominates even the most accurate judgment from any individuals within the group, or wisdom of the crowd, has been widely cited in recent years to advocate for security-based equity crowdfunding. In the context of project financing from a large pool of prospective investors, I show that simple profit-sharing contracts that are similar to but slightly different from typical common stocks could empower individuals with their collective wisdom by coordinating actions guided by dispersed private information. Although such profit-sharing contracts are yet to gain popularity for capital investment, they have been underlying the compensation structures of many human-capital intensive partnership firms. The results provide guidance on security design for the emerging crowdfunding practice