304 research outputs found

    An Application of Wavelets to Finance: The Three-Factor Fama/French Model

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    We use multi-scale analysis and a rolling 250-day window to estimate a widely used standard for empirical asset pricing. The asset pricing model employed is the Fama-French three-factor model. The model is estimated using stock returns for 49 industry stocks of US industry portfolios for the period from July 1969 to September 2017. The rolling window estimation approach allows us to capture the behavior of an investor who periodically reallocates his portfolio. Employing periodic estimates of expected return, we implement a set of long/short investment strategies based on the standard Fama-French three-factor model, and scale versions of the model. We find that during recessions, the higher scale long/short strategies tend to outperform the standard approach. Our results suggest distinct risk dynamics at specific horizons during recessions. We conclude that the information content of the economic phenomena that generate the three-factor model does not follow strict periodicity during recessions, making the wavelet approach more suitable for portfolio managers who must be prepared to rebalance portfolios during official downturns

    Quantifying Human Population Benefits from Renewable Energy Plants

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    The implementation of renewable energy is widely recognized for its positive impact on human health and well-being. We propose methods to quantify these benefits by estimating each renewable energy plant’s impact on human mortality and climate-induced displacement. Utilizing established models (DICE, Mortality Cost of Carbon, and methods from Lenton and Xu), we calculate the avoided heat-related mortalities and loss of human climate niche attributable to avoided CO₂ emissions from renewable energy. Applying this methodology to three California clean energy projects—Morro Bay Wind Energy Area (WEA), Morro Bay Battery Energy Storage System (BESS), and American Energy Services (AES) Bellefield Solar Farm—demonstrates the significant potential of renewable energy to improve human well-being. The Morro Bay WEA is estimated to prevent over 18,000 global deaths and alleviate the need to relocate over 400,000 people due to extreme heat. Our calculations underscore the critical role of renewable energy in mitigating climate change impacts

    A comparative evaluation of dried activated sludge and mixed dried activated sludge with rice husk silica to remove hydrogen sulfide.

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    The aim of this study was to investigate the effectiveness of dried activated sludge (DAS) and mixed dried activated sludge with rice husk silica (DAS & RHS) for removal of hydrogen sulfide (H2S). Two laboratory-scale filter columns (packed one litter) were operated. Both systems were operated under different conditions of two parameters, namely different inlet gas concentrations and different inlet flow rates. The DAS & RHS packed filter showed more than 99.96% removal efficiency (RE) with empty bed residence time (EBRT) of 45 to 90 s and 300 mg/L inlet concentration of H2S. However, the RE decreased to 96.87% with the EBRT of 30 s. In the same condition, the DAS packed filter showed 99.37% RE. Nonetheless, the RE was shown to have dropped to 82.09% with the EBRT of 30 s. The maximum elimination capacity (EC) was obtained in the DAS & RHS packed filter up to 52.32 g/m3h, with the RE of 96.87% and H2S mass loading rate of 54 g/m3h. The maximum EC in the DAS packed filter was obtained up to 44.33 g/m3h with the RE of 82.09% and the H2S mass loading rate of 54 g/m3h. After 53 days of operating time and 54 g/m3h of loading rates, the maximum pressure drop reached to 3.0 and 8.0 (mm H2O) for the DAS & RHS packed and DAS packed filters, respectively. Based on the findings of this study, the DAS & RHS could be considered as a more suitable packing material to remove H2S

    Metagenomic analysis of endophytic bacteria in seed potato (Solanum tuberosum).

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    To date, the association of potato tuber microbiota is poorly understood. In this study, the endophytic bacterial flora of seed potato tubers was identified and the diversity of healthy and unhealthy tubers was compared. Metagenomic DNA extracted from healthy and unhealthy samples of seed potato tubers was used for the analysis of microbial communities. Next generation sequencing of the ∼460 bp v3-v4 region of the 16S rRNA gene was carried out using the Illumina Miseq platform. The data were analysed using the Divisive Amplicon Denoising Algorithm 2 pipeline. Sequence analysis of the potato metagenome identified amplicon sequence variants (ASVs) assigned to 745 different taxa belonging to eight Phyla: Firmicutes (46.2%), Proteobacteria (36.9%), Bacteroidetes (1.8%), Actinobacteria (0.1%), Tenericutes (0.005%), Saccharibacteria (0.003%), Verrucomicrobiota (0.003%), and Acidobacteria (0.001%). In healthy seed potato tubers, 55-99% of ASVs belonged to Firmicutes, including Bacillus, Salinibacillus, Staphylococcus, Lysinibacillus, Paenibacillus, and Brevibacillus genera within the taxonomic order Bacillales. However, in the visually unhealthy tubers, only 0.5-3.9% of ASVs belonged to Firmicutes while 84.1-97% of ASVs belonged to Proteobacteria. This study highlights that diverse bacterial communities colonize potato tubers, which contributes to the understanding of plant-microbe interactions and underscores the significance of metagenomic approaches in agricultural research

    Skull and long bones–Forensic DNA techniques for historic shipwreck human remains

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    Human remains have been recovered from a number of historic shipwrecks and their associated sites, often hundreds of years post-mortem. While remains of victims who have fled following wrecking can be subject to a range of environmental exposures, human remains in marine environments are subject to unique decomposition processes, faunal predation and impacts on DNA. Researchers in museums and academic institutions holding historic shipwreck remains have applied a plethora of scientific testing methods to extract information from artefacts and shipwreck remains. Specialist forensic DNA techniques, often adapted from ancient and archaeological DNA methods, are designed to maximize DNA recovery, and advances in technology and forensic biology have increased options for genotyping compromised human skeletal samples. A vast array of new genetic markers can now be targeted for interrogation to reveal externally visible characteristics, biogeographical ancestry or extended genetic relatives of victims. Some of these techniques have already been applied to historic shipwreck remains. This paper reviews current and emerging forensic DNA techniques available for recovering and revealing genetic information from historic shipwreck remains. It aims to direct investigators conducting genetic testing on historic shipwreck human remains to forensic DNA techniques as a possible approach for yielding further invaluable information

    Comparison of Likelihood Ratios from Probabilistic Genotyping for Two-Person Mixtures across Different Assays and Instruments

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    Continuous probabilistic genotyping (PG) provides a means to estimate the probative value of DNA mixtures tendered as evidence in court and subject to alternative propositions about the contributors to the mixtures. The weight of that evidence, however, may be valued differently, depending on which forensic laboratory undertook the DNA analysis. There is a need, therefore, to have a means for the comparison of likelihood ratios (LRs) generated by continuous PG amongst different laboratories for the same initial DNA sample. Such a comparison would enable the courts and the public to make judgements about the reliability of this type of evidence. There are particular mixtures and methods for which such a comparison is meaningful, and this study explores them for the short tandem repeat (STR) electropherograms of two-person mixtures obtained from the PROVEDIt Database. We demonstrate a common maximum attainable LR for a given set of common STR loci and a given DNA mixture that is consistent across three different STR profiling assays and two different capillary electrophoresis instruments.</jats:p

    Characterisation of identity-informative genetic markers in the Australian population with European ancestry.

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    Identity-informative single nucleotide polymorphisms (iiSNPs) are valuable genetic markers for human identification and kinship testing in forensic casework, especially when the quality and quantity of DNA evidence is not suitable for routine short tandem repeat (STR) profiling. This study analysed 105 buccal samples representing the Australian population with European ancestry in order to assign allele frequencies and conduct population genetic analyses for 94 iiSNPs and 20 STRs. The markers were assessed by calculating relevant forensic statistics and testing for deviations from Hardy-Weinberg and linkage equilibrium. No linkage of statistical significance was observed between any of the pair-wise combinations of the combined 114 identity-informative markers and only one STR exhibited deviation from Hardy-Weinberg equilibrium (D8S1179). The probability of matching genotypes being observed within this population was of the order of 10-23 for STRs, 10-38 for iiSNPs and 10-60 for the combined identity-informative marker panel, improving the ability to discriminate between individuals when calculating likelihood ratios in direct or indirect matching scenarios. Further, the addition of iiSNPs will facilitate identifications when suboptimal STR profiles are recovered from compromised or challenging samples and aid comparisons to genetic relatives for familial or kinship testing

    Forensic DNA phenotyping: Developing a model privacy impact assessment

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    © 2018 Elsevier B.V. Forensic scientists around the world are adopting new technology platforms capable of efficiently analysing a larger proportion of the human genome. Undertaking this analysis could provide significant operational benefits, particularly in giving investigators more information about the donor of genetic material, a particularly useful investigative lead. Such information could include predicting externally visible characteristics such as eye and hair colour, as well as biogeographical ancestry. This article looks at the adoption of this new technology from a privacy perspective, using this to inform and critique the application of a Privacy Impact Assessment to this emerging technology. Noting the benefits and limitations, the article develops a number of themes that would influence a model Privacy Impact Assessment as a contextual framework for forensic laboratories and law enforcement agencies considering implementing forensic DNA phenotyping for operational use

    Uncertainty and the Oracle of Market Returns: Evidence from Wavelet Coherence Analysis

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    Wavelet methodology is employed to investigate the statistical relationship between three well-accepted measures of uncertainty and both market and sector returns. Our primary goal is to determine whether uncertainty is sector specific. Although there are periods when the market works effectively as an oracle capturing uncertainty, we also find sector specific uncertainty. The wavelet equivalent of correlation, coherence, is used to determine the presence of sector specific uncertainty. We find that allowing localized information in the time frequency domain is critical for separating out sector specific uncertainty from market uncertainty
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