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Detecting riparian habitat preferences in “savanna” chimpanzees and associated fauna with strontium isotope ratios: implications for reconstructing chimpanzee-human last common ancestor habitat use.
No full textObjective: Riparian or gallery forests are critical habitats for numerous plants and animals today. Paleoanthropologically, reliance on such habitats inform behavioral and ecological reconstructions; for example, gallery forest habitats likely played a critical role in the transition from ape to hominin in the early Pliocene and may represent a preferred habitat for the last common ancestor of chimpanzees and humans. Direct indicators for gallery forest habitats preference are lacking. The objective of this paper is to assess whether strontium isotope ratios are a reliable indicator of habitat preference for fauna living in and around gallery forests. Materials and Methods: We report bioavailable strontium isotope ratios from the Mugiri River, its tributaries, and its gallery forest (Toro-Semliki Wildlife Reserve, southwestern Uganda), and compare them to surrounding savanna-grassland values. We compare these environmental values to strontium isotopes ratios in faunal tooth enamel to determine if habitat preferences are accurately reflected. Results: Gallery forest and savanna-grassland vegetations have significantly different strontium isotope ratio profiles. We trace these isotopic differences to the influence of the Mugiri tributaries, which originate on Paleoproterozoic gneiss deposits on top of the surrounding escarpments. These isotopic differences in vegetation are mirrored in the tissues of fauna with habitat preferences for either the gallery forest or the surrounding grasslands. Discussion: This research demonstrates the potential of strontium isotope ratios to identify habitat preferences in modern or fossil fauna under proper geologic variability. It provides a methodological model for future studies seeking to reconstruct habitat preferences in early hominins
Ecosystem processes at the watershed scale: Influence of flowpath patterns of canopy ecophysiology on emergent catchment water and carbon cycling
No full textForest canopy water use and carbon cycling traits (WCT) can vary substantially and in spatially organized patterns, with significant impacts on watershed eco-hydrology. In many watersheds WCT may vary systematically along and between hydrologic flowpaths as an adaptation to available soil water, nutrients and microclimate-mediated atmospheric water demand. We hypothesize that the emerging patterns of WCT at the hillslope to catchment scale provide a more resistant ecohydrological system, particularly with respect to drought stress, and the maintenance of high levels of productivity. Rather than attempting to address this hypothesis with species specific patterns, we outline broader functional WCT groups, and explore the sensitivity of water and carbon balances to the representation of canopyWCT functional organization through a modeling approach. We use a well-studied experimental watershed in North Carolina where detailed mapping of forest community patterns are sufficient to describe WCT functional organization. Ecohydrological models typically use broad-scale characterizations of forest canopy composition based on remotely sensed information (e.g., evergreen vs. deciduous), which may not adequately represent the range or spatial pattern of functional group WCT at hillslope to watershed scales. We use three different representations of WCT functional organizations: 1. restricting WCT to deciduous/conifer differentiation, 2. utilizing more detailed, but aspatial, information on local forest community composition, and 3. spatially distributed representation of local forest WCT. Accounting for WCT functional organization information improves model performance not only in terms of capturing observed flow regimes (especially watershed-scale seasonal flow dynamics), but also in terms of representing more detailed canopy eco-hydrologic behavior (e.g. root zone soil moisture, evapotranspiration, and net canopy photosynthesis), especially under dry condition. Results suggest the well-known zonation of forest communities over hydrologic gradients is not just a local adaptation, but also provides a property that regulates hillslope to catchment scale behavior of water use, and drought resistance
Combating Fake News on Social Media with Source Ratings: The Effects of User and Expert Reputation Ratings.
No full textAs a remedy against fake news on social media, we examine the effectiveness of three different mechanisms for source ratings that can be applied to articles when they are initially published: expert rating (where expert reviewers fact-check articles, which are aggregated to provide a source rating), user article rating (where users rate articles, which are aggregated to provide a source rating), and user source rating (where users rate the sources themselves). We conducted two experiments and found that source ratings influenced social media users’ beliefs in the articles and that the rating mechanisms behind the ratings mattered. L ow ratings—which would mark the usual culprits in spreading fake news—had stronger effects than did high ratings. When the ratings were low, users paid more attention to the rating mechanism, and, overall, expert ratings and user article ratings had stronger effects than did user source ratings. We also noticed a second-order effect, where ratings on some sources led users to be more skeptical of sources without ratings, even with instructions to the contrary. A user’s belief in an article, in turn, influenced the extent to which users would engage with the article (e.g., read, like, comment and share). Lastly, we found confirmation bias to be prominent; users were more likely to believe—and spread—articles that aligned with their beliefs. Overall, our results show that source rating is a viable measure against fake news and propose how the rating mechanism should be designed
Third-party signals in crowdfunded microfinance: the role of microfinance institutions
Get PDFCrowdfunded microfinance research has routinely examined how campaign characteristics drive funding to crowdfunding campaigns but has neglected to examine the critical role of the microfinance institution (MFI). We leverage signaling theory to contend that entrepreneurs’ MFI affiliation is a salient third-party signal that shapes the performance of their crowdfunding campaign and examine how the financial and social performance of MFIs drive campaign funding. Our examination of 220,649 loans paired 173 MFIs supports our arguments. We provide insight into the importance of third-party signals in crowdfunding and into how investors seek to balance social motives with financial concerns in crowdfunded microfinance
Persistence of Extra-Medical Prescription Pain Reliever Use and Alcohol Involvement Among United States 12–20 Year Olds
Get PDFThe peak risk of first extra-medical use of prescription pain relievers (PPR) is in mid-adolescence, often after underage drinking has begun. This research aims to investigate discrete classes of similar young people based on their newly incident extra-medical use of PPR and alcohol involvement, with empirical evaluation of the underlying structure of identified subgroups and their epidemiological distributions in the United States (US). The US National Surveys on Drug Use and Health, 2002-2013, sampled, recruited, and assessed 24,789 12-20-year-old newly incident extra-medical PPR users, with self-interviews on PPR, alcohol, and covariates. Latent classes of persistence were formed using PPR and alcohol status variables. Then, age and sex were studied as potentially important predictors of class membership. Analysis-weighted estimates and delta method variances were derived. Three classes were distinguished by extra-medical PPR and alcohol use patterns: (1) Non-persistent (79%), (2) Intermittent (15%), and (3) Persistent (6%). There were no differences across classes by age, but being female was associated with greater odds of being in the Intermittent class or Persistent class compared to the Non-persistent class. Presenting clinical features of alcohol and/or opioid use disorder that have become manifest at or near time of first PPR use can be indicators of persisting in extra-medical use of PPR, particularly for young people who have recently started extra-medical PPR use. Persistent adolescent and young adult extra-medical PPR users require tailored public health prevention and intervention strategies based on their vulnerability to continue use over time
Design and characterization of zero magnetic field chambers for high efficiency neutron polarization transport
No full textSeveral methods of polarized neutron scattering call for a zero magnetic field region to reduce magnetic field integral aberrations while preserving the neutron polarization. Though the design for large angle neutron scattering has been presented in various places, the design characterization and tuning has not been discussed before. In this report, the tuning procedure will be discussed with both neutron polarization transport and utilization of fluxgate magnetometers. As a tuning procedure, polarized neutrons are sensitive to any local field distortions along all trajectories within the beam, but the process is slow. With fluxgates, the entire region cannot be tested, but very fast and precise measurements can be made in accessible regions of interest. Consequently, we would like to benchmark the usage of fluxgates as a fast tuning probe compared with polarization measurements made with neutrons. Polarization transport results for tuned ZF chambers, up to 2.25 m in length, are presented
Mestiçagem and Purity of Blood in Alain Fresnot’s Desmundo
No full textThis article analyses how the themes of mestiçagem and purity of blood are developed in Alain Fresnot’s filmic adaptation of Desmundo, based on the novel by Ana Miranda. It begins by contextualising the critical dialogue that the film establishes with the discourses on national identity circulating in the early 2000s in response to state-sponsored efforts to commemorate the 500th anniversary of Brazil’s “discovery,” and specifically with the resurgence of theories on mestiçagem associated with Gilberto Freyre. It further offers a filmic analysis highlighting two key points. First, it considers how the question of racial mixture is framed and developed by calling attention to the historical case of as órfãs d’el Rei, which was an imperial marriage scheme designed to help reproduce a white Christian population in Portugal’s overseas colonial possessions. Secondly, it provides an analysis of the film’s representation of Ximeno’s character as an ambiguous New Christian of Jewish descent. It argues that the emphasis on the question of purity of blood informs the film’s critical drive to reorient national discussions on mestiçagem and racialisation in Brazil
Decision making over condom use during menses to avert sexually transmissible infections
Get PDFObjective: To test the hypothesis that receptive partners in penile-vaginal intercourse (PVI) who exercise independent decision making over condom use during menses do so to avert STI transmission/acquisition. Methods: Data were collected through a partnership with Clue, the industry-leading female healthapp. A brief web-based questionnaire was developed, translated into 10 languages, and made accessible via a url link sent to Clue users and posted on social media. Inclusion criteria were: age 14 years or older, not being currently pregnant, and engaging in penile-vaginal intercourse (PVI) and condom use during menses in the past 3 months. The analytic sub-sample comprised 12,889 respondents residing in 146 countries. Results: Twenty percent indicated independent decision-making about condom use during menses. Independent decision-making was associated with lower odds of reporting that condoms were used for contraception (AOR=.65; 99% CI=.57-.73) and higher odds that they were used for the prevention of STIs (AOR=1.44; 99% CI=1.28-1.61). A third significant finding pertained to always using condoms during menses; this was less likely among those indicating independent (female only) decision-making (AOR=.69; 99% CI=.62-.78). Non-significant associations with two other outcomes occurred: protecting the partner against menstrual blood, and protecting themselves against semen. Conclusion: Findings from persons in 146 countries strongly support the hypothesis that those exercising independent decision-making over condom use during menses do so to avert STI transmission/acquisition. That only one-fifth of this global sample reported this type of independent decision-making suggests that empowerment-oriented (structural-level) interventions may be advantageous for individuals who are the receptive partner in PVI that occurs during menses
msCRUSH: Fast Tandem Mass Spectral Clustering Using Locality Sensitive Hashing
No full textLarge-scale proteomics projects often generate massive and highly redundant tandem mass spectra(MS/MS). Spectral clustering algorithms can reduce the redundancy in these datasets, and thus speed up database searching for peptide identication, a major bottleneck for proteomic data analysis. The key challenge of spectral clustering is to reduce the redundancy in the MS/MS spectra data, while retaining sufficient sensitivity to identify peptides from the clustered spectra. In this paper, we present the software msCRUSH, which implements a novel spectral clustering algorithm based on the locality sensitive hashing (LSH) technique. When tested on a large-scale proteomic dataset consisting of 23.6 million spectra (including 14.4 million spectra of charge 2+), msCRUSH runs 6.9-11.3x faster than the state-of-the-art spectral clustering software, PRIDE Cluster, while achieving higher clustering sensitivity and comparable accuracy. Using the consensus spectra reported by msCRUSH, commonly used spectra search engines MSGF+ and Mascot can identify 3% and 1% more unique peptides, respectively, comparing to the identification results from the raw MS/MS spectra at the same false discovery rate (1% FDR) of peptide level. msCRUSH is implemented in C++, and is released as open source software
Allocation of Internal Cash Flow when Firms Pay Less Tax
Get PDFWe provide evidence about allocations of cash flow freed up by not paying taxes (“tax-related cash”). Uncertainty about future repayments suggests firms may use tax-related cash more cautiously than other cash flow. We utilize a flow-of-funds model from finance to quantify the relative amounts of tax-related cash associated with various potential uses of operating cash flow. We find firms allocate tax-related cash differently than other after-tax cash flow. Prior studies find tax avoiders hold more cash, and our results suggest this is because firms invest less (and save more) tax-related cash. We also find that the allocation of tax-related cash varies with relative financial constraints, economic uncertainty, and firms' multinational status in ways consistent with prior findings. For example, firms facing relatively higher levels of financial constraints invest a lower (higher) percentage of tax-related cash in capital expenditures (marketable securities and R&D), possibly to preserve funds for future investment opportunities