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Introduction: Having a fat tail is a characteristic of some Iranian native sheep breeds, whose main role is usually to store energy for using in limited food conditions. However, the amount of energy required to store fat in this tissue directly affects the efficiency of meat production and carcass quality. In Iran, the average weight of each carcass is about 15.3 kg, of which 15% is the fat tail. It requires 1.7 kg more feed per kilogram of fat tail than meat (protein), and customers pay a lower price per unit of weight for sheep with heavier fat tail. Today, researchers in the field of animal breeding have a special focus on reducing the weight of the fat tail and increasing the marketability of sheep carcasses. Bone morphogenetic protein 2 (BMP2) belongs to the β-metamorphic growth factor of the β family and plays an important role in bone and cartilage development and, therefore, seems to be the best candidate for the fat-tailed phenotype. Comparison of the results of genotype obtained from Ovine SNP50K Bead Chip in tow fat-tailed breeds with the results obtained in 13 thin tail breeds showed a missense mutation in BMP2 gene, with the frequency of different alleles in these two different groups.Materials and Methods: In this study, in order to detect the polymorphism in BMP2 gene exon 1 and investigation of its relationship with tail fat trait, blood samples from 150 same age ewes of Lori Bakhtiari breed were randomly taken which are maintained in Gahar Dorud sheep breeding center (Dorud, Lorestan). DNA extraction was performed using a special DNA extraction kit (Pars Toos, Iran) according to the manufacturer's instructions. Determination of quality and quantity of extracted DNA was performed using agarose gel electrophoresis and nanodrop spectrophotometer, respectively. BMP2 gene exon 1 was amplified successfully by a pair of specific primer. The accuracy of this process was confirmed by 1.5% agarose gel. Then, using PCR-SSCP technique, 12% polyacrylamide gel and silver nitrate staining, probable polymorphisms were tracked in this position and finally calculation of Chi-square test (χ2) for deviation from Hardy-Weinberg equilibrium (HWE) has been assessed by Popgen (Ver. 1.32) software. The relationship between genotypes and average fat tail weight (Corrected by body weight (BW)) has been analyzed with the PROC GLM procedures in Statistical Analysis System (SAS) v. 9.1 version.Results and Discussion: Based on the results, amplification of BMP2 gene exon 1 was successfully done and three different patterns of polymorphism have been detected through SSCP analysis. Exon 1 of BMP2 gene in Lori Bakhtiari ewes containing A and B alleles with distributions of 197 and 103 and frequency of 65.7% and 34.33%, respectively, that have generated AA, AB and BB genotypes with distribution of 75, 47 and 28 and frequencies of 50%, 31.33% and 18.67%, respectively. Mean comparison of fat tail weight in each genotype using Duncan procedure showed that the effect of genotype on fat tail weight in Lori Bakhtiari breed was significant (P

Sheep breeds originating from arid and semi-arid regions are known for their ability to adapt to the rural environment, climatic fluctuations, and lack of resources. Water scarcity, which is often combined with heat stress, is an urgent problem for sheep farmers in arid regions, which these animals face, causing physical disorders and affecting animal productivity. The purpose of this work is to determine the impact of this problem on this branch of animal husbandry and to find steps to reduce the negative impact of high temperatures and humidity. In the course of writing this article, theoretical general scientific research methods and data analysis from universities in the USA, Brazil, Kazakhstan, Australia, Turkey and Mongolia were used. After analysing the studies and summarising them, the article also provides information on the peculiarities of zoning and climate of Ukraine, which affects the sheep industry. The degree of influence of high wind humidity and temperature on the emergence of scours in sheep is considered. It was found that heat stress is the most important climatic factor that negatively affects livestock production and sometimes even threatens the survival of animals. Among the climatic components that can cause stress on different sheep qualities are ambient temperature, humidity wind movement, photoperiod, solar radiation, wind speed, etc., of which ambient temperature is the most important variable. Although the influence of the season can be significant, the following general responses to drought and heat stress can be identified using animal behavioural data Reduced feed intake and weight loss, increased cooling by evaporation through respiration, production of small amounts of highly concentrated urine, haemoconcentration, high blood salinity and immunosuppression. Improving the heat state of animals by physical, physiological and/or nutritional methods, in addition to following good management practices at the appropriate time, can help animals exposed to heat stress to realise their genetic potential in hot and arid regions, which is of practical value. [ABSTRACT FROM AUTHOR]

Introduction1: Having a fat tail is a characteristic of some Iranian native sheep breeds, whose main role is usually to store energy for using in limited food conditions. However, the amount of energy required to store fat in this tissue directly affects the efficiency of meat production and carcass quality. In Iran, the average weight of each carcass is about 15.3 kg, of which 15% is the fat tail. It requires 1.7 kg more feed per kilogram of fat tail than meat (protein), and customers pay a lower price per unit of weight for sheep with heavier fat tail. Today, researchers in the field of animal breeding have a special focus on reducing the weight of the fat tail and increasing the marketability of sheep carcasses. Bone morphogenetic protein 2 (BMP2) belongs to the β-metamorphic growth factor of the β family and plays an important role in bone and cartilage development and, therefore, seems to be the best candidate for the fat-tailed phenotype. Comparison of the results of genotype obtained from Ovine SNP50K Bead Chip in tow fat-tailed breeds with the results obtained in 13 thin tail breeds showed a missense mutation in BMP2 gene, with the frequency of different alleles in these two different groups. Materials and Methods: In this study, in order to detect the polymorphism in BMP2 gene exon 1 and investigation of its relationship with tail fat trait, blood samples from 150 same age ewes of Lori Bakhtiari breed were randomly taken which are maintained in Gahar Dorud sheep breeding center (Dorud, Lorestan). DNA extraction was performed using a special DNA extraction kit (Pars Toos, Iran) according to the manufacturer's instructions. Determination of quality and quantity of extracted DNA was performed using agarose gel electrophoresis and nanodrop spectrophotometer, respectively. BMP2 gene exon 1 was amplified successfully by a pair of specific primer. The accuracy of this process was confirmed by 1.5% agarose gel. Then, using PCRSSCP technique, 12% polyacrylamide gel and silver nitrate staining, probable polymorphisms were tracked in this position and finally calculation of Chi-square test (χ2) for deviation from Hardy-Weinberg equilibrium (HWE) has been assessed by Popgen (Ver. 1.32) software. The relationship between genotypes and average fat tail weight (Corrected by body weight (BW)) has been analyzed with the PROC GLM procedures in Statistical Analysis System (SAS) v. 9.1 version. Results and Discussion: Based on the results, amplification of BMP2 gene exon 1 was successfully done and three different patterns of polymorphism have been detected through SSCP analysis. Exon 1 of BMP2 gene in Lori Bakhtiari ewes containing A and B alleles with distributions of 197 and 103 and frequency of 65.7% and 34.33%, respectively, that have generated AA, AB and BB genotypes with distribution of 75, 47 and 28 and frequencies of 50%, 31.33% and 18.67%, respectively. Mean comparison of fat tail weight in each genotype using Duncan procedure showed that the effect of genotype on fat tail weight in Lori Bakhtiari breed was significant (P <0.05). AA genotype with average fat tail weight of 5.16 showed higher performance than AB genotype with average fat tail weight of 4.29 and BB genotype with average fat tail weight of 3.76. The results of statistical analysis also showed that the presence of allele A causes heavier fat tail weight and the presence of B allele causes lower fat tail weight (P <0.05). Heterozygosity and Homozygosity observed in this study are 0.3154 and 0.6846, respectively. The significance of the calculated chi-square genotypic frequency in each population at the level of 0.05 in comparison with the chi-square table shows that the studied populations are not in Hardy-Weinberg equilibrium. Which can be attributed to the pressure of selecting on reference population for genetic breeding for fat tail weight at Gahar Dorud sheep breeding center. Today, advances in genomic technologies have multiplied, and if information on loci associated with meat quality traits can be obtained and the genes that control these traits are located on chromosomal sites, they can be incorporated into breeding programs. Breeds should be used with MAS and cause genetic growth and development of these traits. Conclusion: Using molecular detection methods and identifying sheep carrying B alleles and selecting them as the parents of the next generation, we can move towards producing herds with lower fat tail weight and more marketability. [ABSTRACT FROM AUTHOR]

The fat tail/rump is considered as an adaptive selection under harsh challenges which serves as a fat store for the animal. However, the mechanism of fat deposition in tail is unclear. The polymorphisms of candidate sheep CEBPA, PRKAG3 and SREBF1 genes and their relationship with fat deposition between fat-tailed (rumped) and thin-tailed breeds were investigated. Two and one SNPs were identified for PRKAG3 and SREBF1 respectively. Genotyping method was used to analyze genotypes among Altay sheep (fat-rumped breed) and White Suffolk (thin-tailed breed) by Sequenom MassArray. For PRKAG3 gene, a c,1744C>T SNP and a c,1840C>T SNP have been genotyped. For SREBF1 gene, an unknown synonymous c.2878A>G SNP was detected. The genotype distributions in those two loci were significantly different between fat tail and thin tail breeds by chi-square test(P<0.05). [ABSTRACT FROM AUTHOR]

Abstract Background Sheep have developed the ability to store fat in their tails, which is a unique way of reserving energy to survive a harsh environment. However, the mechanism underlying this adaptive trait remains largely unsolved. Results In the present study, we provide evidence for the genetic determinants of fat tails, based on whole genome sequences of 89 individual sheep. A genome-wide scan of selective sweep identified several candidate loci including a region at chromosome 13, a haplotype of which underwent rapid evolution and spread through fat-tailed populations in China and the Middle East. Sequence analysis revealed an inter-genic origin of this locus, which later became a hotspot of ruminant-specific retro-transposon named BovB. Additionally, the candidate locus was validated based on a fat- and thin-tailed cross population. The expression of an upstream gene BMP2 was differentially regulated between fat-tailed and thin-tailed individuals in tail adipose and several other tissue types. Conclusions Our findings suggest the fixation of fat tails in domestic sheep is caused by a selective sweep near a retro-transposable hotspot at chromosome 13, the diversity of which specifically affects the expression of BMP2. The present study has shed light onto the understanding of fat metabolism.

Probability distributions having power-law tails are observed in a broad range of social, economic, and biological systems. We describe here a potentially useful common framework. We derive distribution functions for situations in which a "joiner particle" k pays some form of price to enter a community of size , where costs are subject to economies of scale. Maximizing the Boltzmann-Gibbs-Shannon entropy subject to this energy-like constraint predicts a distribution having a power-law tail; it reduces to the Boltzmann distribution in the absence of economies of scale. We show that the predicted function gives excellent fits to 13 different distribution functions, ranging from friendship links in social networks, to protein-protein interactions, to the severity of terrorist attacks. This approach may give useful insights into when to expect power-law distributions in the natural and social sciences.

Under a climate change perspective, the genetic make-up of local livestock breeds showing adaptive traits should be explored and preserved as a priority. We used genotype data from the ovine 50 k Illumina BeadChip for assessing breed autozygosity based on runs of homozygosity (ROH) and fine-scale genetic structure and for detecting genomic regions under selection in 63 Tunisian sheep samples. The average genomic inbreeding coefficients based on ROH were estimated at 0.017, 0.021, and 0.024 for Barbarine (BAR, n = 26), Noire de Thibar (NDT, n = 23), and Queue fine de l'Ouest (QFO, n = 14) breeds, respectively. The genomic relationships among individuals based on identity by state (IBS) distance matrix highlighted a recent introgression of QFO into the BAR and a genetic differentiation of NDT samples, possibly explained by past introgression of European gene pools. Genome-wide scan for ROH across breeds and within the BAR sample set identified an outstanding signal on chromosome 13 (46.58–49.61 Mbp). These results were confirmed using FST index, differentiating fat vs. thin-tailed individuals. Candidate genes under selection pressure (CDS2, PROKR1, and BMP2) were associated to lipid storage and probably preferentially selected in fat-tailed BAR animals. Our findings suggest paying more attention to preserve the genetic integrity and adaptive alleles of local sheep breeds.

Fat deposition in sheep tails is as a result of a complicated mechanism. Mongolian sheep (MG) and Small Tail Han sheep (STH) are two fat-tailed Chinese indigenous sheep breeds while DairyMeade and East Friesian (DS) are two thin-tailed dairy sheep breeds recently introduced to China. In this study, population genomics analysis was applied to identify candidate genes associated with sheep tails based on an in-depth whole-genome sequencing of MG, STH and DS. The selective signature analysis demonstrated that GLIS1, LOC101117953, PDGFD and T were in the significant divergent regions between DS and STH–MG. A nonsynonymous point mutation (g.27807636G>T) was found within GLIS1 in STH–MG and resulted in a Pro to Thr substitution. As a pro-adipogenic factor, GLIS1 may play critical roles in the mesodermal cell differentiation during fetal development affecting fat deposition in sheep tails. This study gives a new insight into the genetic basis of species-specific traits of sheep tails. [ABSTRACT FROM AUTHOR]

Sheep is a significant agricultural animal and food source for people worldwide. The fat tail/rump is considered as an adaptive selection under harsh challenges which serves as a fat store for the animal. Thyroid hormone responsive (THRSP) is a crucial protein for cellular de novo lipogenesis. THRSP gene encodes a nuclear protein which regulates fatty acid synthesis in lipogenic tissues. Identification of single nucleotide polymorphisms (SNPs) of sheep THRSP gene and their association with fat deposition were investigated using Altay and White Suffolk sheep. In addition, the messenger RNA expression profiling of THRSP in fat-tailed and thin-tailed breeds was compared among 8 different tissues. Four SNPs have been detected in position g. 205A>C, c. 52C>T, c. 364A>T and c. 1031C>T of THRSP gene. Genotyping method was used to analyze genotypes among Altay sheep (fat-rumped breed) and White Suffolk (thintailed breed) by Sequenom MassArray. In the c.1031C>T locus, the frequency of T allele of fat-tail breed was significantly (p<0.001) higher than that of the thin-tailed breed using F test, which suggest that this locus may be associated with fat deposition in fat-tail breed. Gene expression levels in both subcutaneous adipose and tail fat tissues were significantly (p<0.01) higher than the other tissues analyzed. Levels of THRSP expression in liver, subcutaneous adipose and tail fat tissues in Tan sheep (thin-tailed breed) were significantly (p<0.01) higher than that in Altay sheep (fat-tailed breed). The results obtained might expand our understanding of the important regulating role of THRSP gene in lipogenesis in fat-tailed sheep breed. [ABSTRACT FROM AUTHOR]

This study provides an explanation for the emergence of power laws in asset trading volume and returns. We consider a two‐state model with binary actions, where traders infer other traders' private signals regarding the value of an asset from their actions and adjust their own behavior accordingly. We prove that this leads to power laws for equilibrium volume and returns whenever the number of traders is large and the signals for asset value are sufficiently noisy. We also provide numerical results showing that the model reproduces observed distributions of daily stock volume and returns. [ABSTRACT FROM AUTHOR]

Statistical significance measures the reliability of a result obtained from a random experiment. We investigate the number of repetitions needed for a statistical result to have a certain significance. In the first step, we consider binomially distributed variables in the example of medication testing with fixed placebo efficacy, asking how many experiments are needed in order to achieve a significance of 95%. In the next step, we take the probability distribution of the placebo efficacy into account, which to the best of our knowledge has not been done so far. Depending on the specifics, we show that in order to obtain identical significance, it may be necessary to perform twice as many experiments than in a setting where the placebo distribution is neglected. We proceed by considering more general probability distributions and close with comments on some erroneous assumptions on probability distributions which lead, for instance, to a trivial explanation of the fat tail.

Recent empirical research has documented the clustered volatility and fat tails of return distribution in stock markets, yet returns are uncorrelated over time. Certain agent-based theoretical models attempt to explain the empirical features in terms of investors' order-splitting or dynamic switching strategies, both of which are frequently used by actual stock investors. However, little theoretical research has discriminated among the behavioral assumptions within a model and compared the impacts of the assumptions on the empirical features. Nor has the research simultaneously replicated the return features and empirical features on market microstructure, such as patterns of order choice. This study constructs an artificial limit order market in which investors split orders into small pieces or use fundamental and trend-following predictors interchangeably over time. We demonstrate that, on one hand, the market that features strategies with order splitting and dynamic predictor selection can independently replicate clustered volatility and fat tails with near-zero return autocorrelations. However, we also show that patterns of order choice do not match those found in certain previous empirical studies in both types of economies. Thus, we conclude that, in reality, the two strategies can work to generate the empirical return features but that investors may also use other strategies in actual stock markets. We also demonstrate that the impact of both strategies on the volatility persistence tends to be greater as the number of traders increases in the market; this finding implies that the order-splitting strategy and dynamic predictor selection are more crucial for the empirical phenomena pertaining to larger capital stocks. [ABSTRACT FROM AUTHOR]

The literature on portfolio selection and risk measurement has considerably advanced in recent years. The aim of the present paper is to trace the development of the literature and identify areas that require further research. This paper provides a literature review of the characteristics of financial data, commonly used models of portfolio selection, and portfolio risk measurement. In the summary of the characteristics of financial data, we summarize the literature on fat tail and dependence characteristic of financial data. In the portfolio selection model part, we cover three models: mean-variance model, global minimum variance (GMV) model and factor model. In the portfolio risk measurement part, we first classify risk measurement methods into two categories: moment-based risk measurement and moment-based and quantile-based risk measurement. Moment-based risk measurement includes time-varying covariance matrix and shrinkage estimation, while moment-based and quantile-based risk measurement includes semi-variance, VaR and CVaR. [ABSTRACT FROM AUTHOR]

The Lanzhou Fat-Tail sheep (LFTS, long fat-tailed sheep) is an endangered sheep breed in China with a fat tail compared to the traditional local varieties, Small Tail Han sheep (STHS, thin-tailed sheep) with a small tail, and Tibetan sheep (TS, short thin-tailed sheep) with a little tail. However, little is known regarding how tail fat deposition is regulated by long noncoding RNA (lncRNA). To evaluate the lncRNA and mRNA associated with tail fat deposition and development among these breeds, high-throughput RNA sequencing of three individuals each of LFTS, STHS, and TS were performed and analyzed in this study. RNA sequencing data from these three groups revealed 10 differentially expressed genes (DEGs) and 37 differentially expressed lncRNAs between the LFTS and STHS groups, 390 DEGs and 59 differentially expressed lncRNAs between the LFTS and TS groups, and 80 DEGs and 16 differentially expressed lncRNAs between the STHS and TS groups (p-value < 0.05 and fold change ≥ 2), respectively. Gene Ontology and pathway analysis of DEGs and target genes of differentially expressed lncRNAs revealed enrichment in fatty acid metabolism and fatty acid elongation-related pathways that contribute to fat deposition. Subsequently, the expression of 14 DEGs and 6 differentially expressed lncRNAs was validated by quantitative real-time PCR. Finally, two co-expression networks of differentially expressed mRNA and lncRNAs were constructed. The results suggested that some differentially expressed lncRNAs (TCONS_00372767, TCONS_00171926, TCONS_00054953, and TCONS_00373007) may play crucial roles as core lncRNAs in tail fat deposition processes. In summary, the present study extends the sheep tail fat lncRNA database and these differentially expressed mRNA and lncRNAs may provide novel candidate regulators for future genetic and molecular studies on tail fat deposition of sheep.

Highlights • Bernoullis original utility function is reference dependent. • A reference dependent loss aversion index can be constructed from Bernoullis original utility function. • A modified Fishers z-transform test can be used to test the loss aversion index. • Large and small sample tests of loss aversion index are introduced. Abstract Some analysts claim that Bernoulli's utility function is "reference-independent", so it is not able to generate a loss aversion index, and that the theoretical framework of Prospect Theory (PT) is required to achieve those results. This paper examines that claim and finds that the geometry of Bernoulli's original utility function specification either explains or implies key elements of PT: reference dependence and a loss aversion index. Theory and evidence show that the loss aversion index constructed from reference wealth in Bernoulli's utility specification is in the domain of attraction of a stable law. That is, its distribution is a slow varying function with a fat tail that decays like a power law. Additionally, the index can be tested with a modified Fisher z-transform test. Bernoulli's utility function also sheds light on why loss aversion may be over-estimated under PT. In a nutshell, Bernoulli's utility function is alive and well. [ABSTRACT FROM AUTHOR]

We present an experimental study of pattern variability and defectivity, based on a large data set with >112 million critical dimension (CD) and via area measurements from a Hermes Microvision Inc. (HMI) highthroughput e-beam tool. The test case is a 10-nm node static random-access memory via array patterned with a deep ultraviolet immersion litho-etch-litho-etch process, where we see a variation in mean size and litho sensitivities between different unique via patterns that leads to significant differences in defectivity. The large data volume made available by high-throughput inspection capability of the HMI eP5 tool enables analysis to reliably distinguish global and local CD uniformity variations, including a breakdown into local systematics and stochastics. From a closer inspection of the tail end of the distributions and estimation of defect probabilities, we conclude that there is a common defect mechanism and defect threshold despite the observed differences of specific pattern characteristics. In addition, we studied wafer fingerprints for both global CD uniformity (GCDU) and local CD uniformity (LCDU), including stochastics. We used LCDU and GCDU wafer maps to identify correlations between those parameters and defect count. We expect that the analysis methodology presented can be applied for defect probability modeling as well as general process qualification in the future. [ABSTRACT FROM AUTHOR]

The Lanzhou Fat-Tail sheep (LFTS, long fat-tailed sheep) is an endangered sheep breed in China with a fat tail compared to the traditional local varieties, Small Tail Han sheep (STHS, thin-tailed sheep) with a small tail, and Tibetan sheep (TS, short thin-tailed sheep) with a little tail. However, little is known regarding how tail fat deposition is regulated by long noncoding RNA (lncRNA). To evaluate the lncRNA and mRNA associated with tail fat deposition and development among these breeds, high-throughput RNA sequencing of three individuals each of LFTS, STHS, and TS were performed and analyzed in this study. RNA sequencing data from these three groups revealed 10 differentially expressed genes (DEGs) and 37 differentially expressed lncRNAs between the LFTS and STHS groups, 390 DEGs and 59 differentially expressed lncRNAs between the LFTS and TS groups, and 80 DEGs and 16 differentially expressed lncRNAs between the STHS and TS groups (p -value < 0.05 and fold change ≥ 2), respectively. Gene Ontology and pathway analysis of DEGs and target genes of differentially expressed lncRNAs revealed enrichment in fatty acid metabolism and fatty acid elongation-related pathways that contribute to fat deposition. Subsequently, the expression of 14 DEGs and 6 differentially expressed lncRNAs was validated by quantitative real-time PCR. Finally, two co-expression networks of differentially expressed mRNA and lncRNAs were constructed. The results suggested that some differentially expressed lncRNAs (TCONS_00372767, TCONS_00171926, TCONS_00054953 , and TCONS_00373007) may play crucial roles as core lncRNAs in tail fat deposition processes. In summary, the present study extends the sheep tail fat lncRNA database and these differentially expressed mRNA and lncRNAs may provide novel candidate regulators for future genetic and molecular studies on tail fat deposition of sheep. [ABSTRACT FROM AUTHOR]

Fat-tailed sheep have commercial value because consumers prefer high-protein and low-fat food and producers care about feed conversion rate. However, fat-tailed sheep still have some scientific significance, as the fat tail is commonly regarded as a characteristic of environmental adaptability. Finding the candidate genes associated with fat tail formation is essential for breeding and conservation. To identify these candidate genes, we applied FST and hap FLK approaches in fat- and thin-tailed sheep with available 50K SNP genotype data. These two methods found 6.24 Mb of overlapped regions and 43 genes that may associated with fat tail development. Gene annotation showed that HOXA11, BMP2, PPP1 CC, SP3, SP9, WDR92, PROKR1 and ETAA1 may play important roles in fat tail formation. These findings provide insight into tail fat development and a guide for molecular breeding and conservation. [ABSTRACT FROM AUTHOR]

Despite widespread claims of power laws across the natural and social sciences, evidence in data is often equivocal. Modern data and statistical methods reject even classic power laws such as Pareto's law of wealth and the Gutenberg-Richter law for earthquake magnitudes. We show that the maximum-likelihood estimators and Kolmogorov-Smirnov (K-S) statistics in widespread use are unexpectedly sensitive to ubiquitous errors in data such as measurement noise, quantization noise, heaping and censorship of small values. This sensitivity causes spurious rejection of power laws and biases parameter estimates even in arbitrarily large samples, which explains inconsistencies between theory and data. We show that logarithmic binning by powers of λ > 1 attenuates these errors in a manner analogous to noise averaging in normal statistics and that λ thereby tunes a trade-off between accuracy and precision in estimation. Binning also removes potentially misleading within-scale information while preserving information about the shape of a distribution over powers of λ , and we show that some amount of binning can improve sensitivity and specificity of K-S tests without any cost, while more extreme binning tunes a trade-off between sensitivity and specificity. We therefore advocate logarithmic binning as a simple essential step in power-law inference.

A comparative study of artificial neural network (ANN) and multiple regression is made to predict the fat tail weight of Balouchi sheep from birth, weaning and finishing weights. A multilayer feed forward network with back propagation of error learning mechanism was used to predict the sheep body weight. The data (69 records) were randomly divided into two subsets. The first subset is the training set comprising of 75 percent data (52 records) to build the neural network model and test data set comprising of 25 percent (17 records), which is not used during the training and is used to evaluate performance of different models. The mean relative error was significantly (P<0.01) lower for ANN than the MLR model. The coefficient of determination (R²) values computed for the body measurements were generally higher (0.93) using ANN model than the multiple linear regression (MLR) model (0.81). The ANN model improved the mean squared error (MSE) of the MLR model by 59% and R² by 15% that the ANN represents a valuable tool for predicting of lamb fat tail weight from birth, weaning and finishing weights. [ABSTRACT FROM AUTHOR]

The purpose of the present study is to analyze the behaviors of the Iranian stock market using a non-Gaussian distribution function developed by a physicist called Castaing. Data were gathered on a daily basis from December 2008 to August 2016. In order to estimate the Castaing function, the Bayesian method and the Marcov chain Mont Carlo simulations were adopted. The results indicate a non-Gaussian distribution function with fat tails. Based on the findings, the probability of unexpected crises in the Iranian stock market could not be ignored. [ABSTRACT FROM AUTHOR]

We show the existence of self-similar solutions with fat tails for Smoluchowski's coagulation equation for homogeneous kernels satisfying C 1 ( x − a y b + x b y − a ) ≤ K ( x , y ) ≤ C 2 ( x − a y b + x b y − a ) with a > 0 and b < 1 . This covers especially the case of Smoluchowski's classical kernel K ( x , y ) = ( x 1 / 3 + y 1 / 3 ) ( x − 1 / 3 + y − 1 / 3 ) . For the proof of existence we take a self-similar solution h ε for a regularized kernel K ε and pass to the limit ε → 0 to obtain a solution for the original kernel K . The main difficulty is to establish a uniform lower bound on h ε . The basic idea for this is to consider the time-dependent problem and to choose a special test function that solves the dual problem. [ABSTRACT FROM AUTHOR]

Identification of genomic regions that have been targets of selection for phenotypic traits is one of the most challenging applications of dense marker panels in animal genetics. In this study, a genomewide scan using approximately 50,000 SNP was performed in an attempt to identify genomic regions associated with fat deposition in sheep, the importance of this not only being limited to livestock facing future climate changes but also for elucidating the physiology of lipid metabolism. The genotyping results obtained with the Ovine SNP50K BeadChip in 2 fat tail breeds were compared with those obtained in 13 thin tail breeds. Direct sequencing of the annotated genes located in proximity to the markers with opposite allele frequency in thin tail vs. fat tail sheep gave additional SNP of interest. To further confirm the results of the genomewide scan, we genotyped the SNP within these genes in the 2 groups of sheep. A missense mutation in the BMP2 gene, with different allele frequency in the 2 groups, was detected. The results indicated BMP2 and VNRT as the most probable genes involved in the fat tail phenotype. [ABSTRACT FROM AUTHOR]

We review multifractal surfaces focusing on a comparison between Lucena and Stanley approaches. The multifractal model as presented by Stanley is basically a multinomial measure over a standard partition of a square. The Lucena approach is geometric oriented, the multifractality is not imposed over a regular lattice, but the lattice itself follows a partition where area tiles obey a multifractal distribution. The non-trivial tilling has a distribution of neighbors of lattice elements that shows a fat tail. Despite the strong differences in the two bidimensional models, both Liacir and Stanley multifractals can be reduced to the same object in one dimension. The message of this article is that there is no unique multifractal object in two dimensions and, as a consequence, we should caution about algorithms that estimate multifractal spectrum in two dimensions because it is not clear what kind of multifractality is being measured. Finally we propose a mixed Lucena-Stanley bimultifractal, an object that combines a multifractal measure over a geometric multifractal tilling. [ABSTRACT FROM AUTHOR]

Suppose that there is a probability density function for how bad things might get, but that the overall rate at which this probability density function slims down to approach zero in the tail is uncertain. The paper shows how a basic precautionary principle of tail fattening could then apply. The worse is the contemplated damage, the more should a decision maker consider the bad tail to be among the relatively fatter-tailed possibilities. A rough numerical example is applied to the uncertain tail distribution of climate sensitivity. [ABSTRACT FROM AUTHOR]

On-farm survey of farmers' breeding practices, breeding objectives, and selection criteria and on-station feedlot performance evaluation of Washera sheep were undertaken in Ethiopia. The survey revealed that most (79.8%) of the farmers had no breeding ram. The mating system was predominantly uncontrolled. A majority (75.5%) of the sheep owners reported that they herded their sheep flock by mixing with other livestock species mainly with cattle. During grazing, 44.6% of the farmers mix their sheep flock with neighboring sheep flocks. The major sheep production objective was to generate income from the sale of live sheep. Fast growth, appearance, coat color, and pedigree performance were important ram selection criteria, respectively. Ability to breed at early age, pedigree information, mothering ability, and lambing interval were important selection criteria for ewe, respectively. The on-station performance study involved evaluation of feedlot gains and carcass production under five levels of feeding regimes (300, 400, 500, 600, and 700 g day of concentrate feed) for a period of 93 days. The results indicated that the feedlot growth and carcass performance of Washera sheep were very high, with average daily weight gains of up to 126 g and carcass weight of 16 kg, with the optimal level of supplementation for Washera sheep being at 500 g of concentrate per day for a period of 93 days. [ABSTRACT FROM AUTHOR]

ording to behavioral finance theories, in this article we develop a dynamic model with heterogeneous traders, where the asset price is determined by the interaction among four different groups of agents: trend reversers, trend followers, risk averters and risk seekers. The main purpose of the study is centered on modeling and testing how the market efficiency changes along with the changes of agent's behavior preference without exogenous influence. Combining with the assumption of risk appetite and prospect theory, focusing on analyzing the rules for selecting strategies, we establish a more reliable and comprehensive dynamic mechanism. In particular, our study suggests that diversified trading strategies will help to realize market efficiency. [ABSTRACT FROM AUTHOR]

It is well known that the normal distribution model fails to describe the fat tails of markets. The Lévy stable distribution model, meanwhile, has fat tails but leads to an infinite variance, thus complicating risk estimation. This study introduces truncated Lévy flight (TLF) - a better distribution model that has fat tails, finite variance, and more importantly, scaling properties. The paper uses TLF to estimate the downside risk of a variety of asset classes. The downside risk measure used is the conditional value-at-risk (CVaR). The study shows that the lognormal model can underestimate the monthly CVaR by 2.27 per cent for the S&P 500 Index, 0.48 per cent for the US Long-Term Government Bond Index, and 1.16 per cent for the MSCI UK Equity Index. Moreover, the paper extends a univariate TLF model to a multivariate TLF model to study the impact of fat tails on portfolios' downside risk and wealth accumulation. [ABSTRACT FROM AUTHOR]

Dispersal has long been recognized as a crucial factor affecting population dynamics. Several studies on long-distance dispersal revealed a peculiarity now widely known as a problem of "fat tail": instead of the rate of decay in the population density over large distances being described by a normal distribution, which is apparently predicted by the standard diffusion approach, field data often show much lower rates such as exponential or power law. The question as to what are the processes and mechanisms resulting in the fat tail is still largely open. In this note, by introducing the concept of a statistically structured population, we show that a fat-tailed longdistance dispersal is a consequence of the fundamental observation that individuals of the same species are not identical. Fat-tailed dispersal thus appears to be an inherent property of any real population. We show that our theoretical predictions are in good agreement with available data. [ABSTRACT FROM AUTHOR]

Abstract: Populations do not remain fixed in space. Their distribution changes continuously due to the impact of environmental factors, such as wind, and/or due to self-motion of individuals. A cornerstone for understanding mechanisms of dispersal is identification of factors affecting the dispersal curve, in particular, its rate of decay at large distance. The standard random walk approach resulting in a dispersal curve with a ‘thin’ Gaussian tail was eventually opposed by the theory of Lévy flights, which predicts a more realistic ‘fat’ tail with a lower rate of decay. However, here we argue that the Gaussian large-distance asymptotics is more an artefact of an oversimplified description of the dispersing population rather than an immanent property of the random walk diffusion. Specifically, we show that, when some inherent population structure is taken into account, diffusion results in a dispersal curve with either exponential or power law rate of decay. Our theoretical results appear to be in a very good agreement with some available data. [Copyright &y& Elsevier]

We analyze high-resolution foreign exchange data consisting of 20 million data points of USD-JPY for 13 years to report firm statistical laws in distributions and correlations of exchange rate fluctuations. A conditional probability density analysis clearly shows the existence of trend-following movements at time scale of 8-ticks, about 1 min. [Copyright &y& Elsevier]

• The pattern of fat deposition in the tail of F2 sheep changed and evolved. • SCD , ESR1 , EMR1 and PHYH genes play a direct role in tail fat deposition. • GPAM , STAT3 and ALDH1A1 genes indirectly regulate the evolution of fat tails in sheep. Fat tail is one of the most important domesticated characteristics in sheep; however its molecular mechanism is poorly understood. Here we took small-tailed F2 hybrid of wild Argali sheep and typical fat-tailed Bashby sheep as research object. First, histological analysis revealed that the mean diameter and area in tail and subcutaneous fat cells, and surface density in tail fat in Bashby sheep were significantly larger than that in F2 sheep, and surface density of fat in subcutaneous fat in Bashby sheep was significantly lower than that in F2 sheep. Second, 873 differentially expressed genes (DEGs) of tail fat between Bashby and F2 sheep were identified by RNA-seq. Third, the tissue expression profile and relative expression difference between Bashby and F2 sheep of 7 of 873 DEGs were analyzed by RT-PCR. SCD, ESR1 , EMR1, PHYH , STAT3 and GPAM genes were highly expressed in fat, muscle and liver, and ALDH1A1 were highly expressed in small intestine. In addition, the expressions of SCD , PHYH and CPAM genes in tail fat of F2 sheep were lower than that of Bashby sheep, while the expression patterns of ESR1 and EMR1 were reversed. Our findings will not only help understand molecular mechanism of fat tail, but also provide theoretical material in sheep evolution. [ABSTRACT FROM AUTHOR]

Statistical significance measures the reliability of a result obtained from a random experiment. We investigate the number of repetitions needed for a statistical result to have a certain significance. In the first step, we consider binomially distributed variables in the example of medication testing with fixed placebo efficacy, asking how many experiments are needed in order to achieve a significance of 95%. In the next step, we take the probability distribution of the placebo efficacy into account, which to the best of our knowledge has not been done so far. Depending on the specifics, we show that in order to obtain identical significance, it may be necessary to perform twice as many experiments than in a setting where the placebo distribution is neglected. We proceed by considering more general probability distributions and close with comments on some erroneous assumptions on probability distributions which lead, for instance, to a trivial explanation of the fat tail. [ABSTRACT FROM AUTHOR]

Under a climate change perspective, the genetic make-up of local livestock breeds showing adaptive traits should be explored and preserved as a priority. We used genotype data from the ovine 50 k Illumina BeadChip for assessing breed autozygosity based on runs of homozygosity ( ROH ) and fine-scale genetic structure and for detecting genomic regions under selection in 63 Tunisian sheep samples. The average genomic inbreeding coefficients based on ROH were estimated at 0.017, 0.021, and 0.024 for Barbarine (BAR , n = 26), Noire de Thibar (NDT , n = 23), and Queue fine de l'Ouest (QFO , n = 14) breeds, respectively. The genomic relationships among individuals based on identity by state (IBS) distance matrix highlighted a recent introgression of QFO into the BAR and a genetic differentiation of NDT samples, possibly explained by past introgression of European gene pools. Genome-wide scan for ROH across breeds and within the BAR sample set identified an outstanding signal on chromosome 13 (46.58–49.61 Mbp). These results were confirmed using F ST index, differentiating fat vs. thin-tailed individuals. Candidate genes under selection pressure (CDS2 , PROKR1, and BMP2) were associated to lipid storage and probably preferentially selected in fat-tailed BAR animals. Our findings suggest paying more attention to preserve the genetic integrity and adaptive alleles of local sheep breeds. [ABSTRACT FROM AUTHOR]