Sex-, Diet-, and Cancer-Dependent Epistatic Effects on Complex Traits in Mice

The genetic basis of quantitative traits such as body weight and obesity is complex, with several hundred quantitative trait loci (QTLs) known to affect these and related traits in humans and mice. It also has become increasingly evident that the single-locus effects of these QTLs vary considerably depending on factors such as the sex of the individuals and their dietary environment, and we were interested to know whether this context-dependency also applies to two-locus epistatic effects of QTLs as well. We therefore conducted a genome scan to search for epistatic effects on 13 different weight and adiposity traits in an F2 population of mice (created from an original intercross of the FVB strain with M16i, a polygenic obesity model) that were fed either a control or a high-fat diet and half of which harbored a transgene (PyMT) that caused the development of metastatic mammary cancer. We used a conventional interval mapping approach with SNPs to scan all 19 autosomes, and found extensive epistasis affecting all of these traits. More importantly, we also discovered that the majority of these epistatic effects exhibited significant interactions with sex, diet, and/or presence of PyMT. Analysis of these interactions showed that many of them appeared to involve QTLs previously identified as affecting these traits, but whose single-locus effects were variously modified by two-locus epistatic effects of other QTLs depending on the sex, diet, or PyMT environment. It was concluded that this context-dependency of epistatic effects is an important component of the genetic architecture of complex traits such as those contributing to weight and obesity

Computational Fluid Dynamics (CFD) Applied to a Glass Vaporization Chamber for Introduction of Micro- or Nano-Size Samples into Lab-Based ICPs and to a CFD-Derived (and Rapidly Prototyped Via 3D Printing) Smaller-Size Chamber for Portable Microplasmas

Computational fluid dynamics (CFD) is used extensively in many industries ranging from aerospace engineering to automobile design. We applied CFDs to simulate flows inside vaporization chambers designed for micro- or nano-sample introduction into conventional, lab-based inductively coupled plasmas (ICPs). Simulation results were confirmed using smoke visualization experiments (akin to those used in wind tunnels) and were verified experimentally using an ICP-optical emission spectrometry (ICP-OES) system with a fast-response photomultiplier tube (PMT) detector, an ICP-OES system with a slower-response charge injection device (CID) detector, and an ICP-mass spectrometry (ICP-MS) system. A pressure pulse (defined as a momentary decrease of the optical emission intensity of ICP background) was not observed when employing widely used ICPs either with a CID detector or with ICP-MS. Overall, the simulations proved to be highly beneficial, for example, detection limits improved by as much as five times. Using CFD simulations as a guide, a rapidly prototyped, 3D-printed and smaller-size vaporization chamber (a scaled-down version of that used with ICPs) is being evaluated for potential use with a portable, battery-operated microplasma. Details are provided in this chapter

Risk and protective factors for transgender youths' substance use.

Research at the intersection of substance use and protective factors among transgender youth is scarce; emerging evidence suggests high risk for substance use for transgender youth. We analyzed data from 323 transgender youth aged 14-18 (Mₐₑ = 16.67) to investigate the extent that risk (enacted stigma) and protective factors (support from family, school, friends) were related to substance use (i.e., cannabis and tobacco use, binge drinking). Enacted stigma was linked to higher odds of substance use behaviors, family connectedness was related to lower levels of tobacco and cannabis use, and more than one protective factor significantly lowered the probability of engaging in substance use behaviors. Support from multiple sources may be differentially protective against substance use for transgender youth

Bayesian High-Redshift Quasar Classification from Optical and Mid-IR Photometry

We identify 885,503 type 1 quasar candidates to i<22 using the combination of optical and mid-IR photometry. Optical photometry is taken from the Sloan Digital Sky Survey-III: Baryon Oscillation Spectroscopic Survey (SDSS-III/BOSS), while mid-IR photometry comes from a combination of data from the Wide-Field Infrared Survey Explorer (WISE) "ALLWISE" data release and several large-area Spitzer Space Telescope fields. Selection is based on a Bayesian kernel density algorithm with a training sample of 157,701 spectroscopically-confirmed type-1 quasars with both optical and mid-IR data. Of the quasar candidates, 733,713 lack spectroscopic confirmation (and 305,623 are objects that we have not previously classified as photometric quasar candidates). These candidates include 7874 objects targeted as high probability potential quasars with 3.5<z<5 (of which 6779 are new photometric candidates). Our algorithm is more complete to z>3.5 than the traditional mid-IR selection "wedges" and to 2.2<z<3.5 quasars than the SDSS-III/BOSS project. Number counts and luminosity function analysis suggests that the resulting catalog is relatively complete to known quasars and is identifying new high-z quasars at z>3. This catalog paves the way for luminosity-dependent clustering investigations of large numbers of faint, high-redshift quasars and for further machine learning quasar selection using Spitzer and WISE data combined with other large-area optical imaging surveys.Comment: 54 pages, 17 figures; accepted by ApJS Data for tables 1 and 2 available at http://www.physics.drexel.edu/~gtr/outgoing/optirqsos/data/master_quasar_catalogs.011414.fits.bz2 and http://www.physics.drexel.edu/~gtr/outgoing/optirqsos/data/optical_ir_quasar_candidates.052015.fits.bz

Investigating the efficacy of a proposed marine protected area for the Endangered humphead wrasse Cheilinus undulatus at a remote island group in Seychelles

The humphead wrasse Cheilinus undulatus is an iconic, ecologically important and Endangered fish species associated with coral reefs in the Indo-Pacific region. Due to its large size and complex life history characteristics, it is vulnerable to overfishing and has undergone substantial population declines in parts of its range. Knowledge of the species’ movement ecology is currently limited to only 2 previous studies, and very little is known about populations in the western Indian Ocean. The present study aimed to use passive acoustic telemetry to investigate the importance of a remote coral reef to a population of humphead wrasse in the Republic of Seychelles, and subsequently assess the efficacy of a proposed marine protected area at this location for protection of the species. Tagged fish (n = 20) exhibited persistent (\u3e500 d) site fidelity, with low dispersal distances (mean ± SD: 6.44 ± 4.0 km) and restricted core activity spaces (50% Brownian bridge kernel utilization density: 0.91 ± 0.61 km2). Additionally, the study site was home to a group of large (total length 97.9 ± 20.6 cm) and currently unexploited humphead wrasse that showed long-term predictable site fidelity and thus could be vulnerable to over-exploitation. The establishment of a proposed no-take marine protected area at the study site would encompass the core home range area of all tagged humphead wrasse and could effectively conserve this stronghold of Endangered fish to ensure the persistence of the species in Seychelles waters

Detecting a decline in serial homicide : have we banished the devil from the details?

The current research provides perspective regarding the true prevalence of serial murderers in modern society and addresses the conflict between the evidenced decline in serial homicide and the viewpoint that the phenomenon is increasing. The likelihood that serial murderers are responsible for most unresolved homicides and missing persons is examined in the context of a declining prevalence. A mixed methods approach was used, consisting of a review of a sample of unresolved homicides, a comparative analysis of the frequency of known serial homicide series and unresolved serial homicide series, and semi-structured interviews of experts. In failing to become serial killers, aspiring and probable serial killers and spree killers have impacted the rate of serial murder by not reaching their potential. The past decade contained almost half the cases (13%) that existed at the 1980s peak of serial homicide (27%). Only 282 (1.3%) strangled females made up the 22,444 unresolved homicides reviewed. Most expert respondents thought it unreasonable that any meaningful proportion of missing persons cases are victims of serial homicide. Technology, shifts in offending behavior, proactive law enforcement action, and vigilance of society have transformed serial killing and aids in viewing offenders as people impacted by societal shifts and cultural norms. The absence of narrative details inhibited some aspects of the review. An exhaustive list of known unresolved serial homicide series remained elusive as some missing persons are never reported. Future research should incorporate those intending to murder serially, but whose efforts were stalled by arrest, imprisonment, or death

A Spectroscopic Survey of Faint Quasars in the SDSS Deep Stripe: I. Preliminary Results from the Co-added Catalog

In this paper we present the first results of a deep spectroscopic survey of faint quasars in the Sloan Digital Sky Survey (SDSS) Southern Survey, a deep survey carried out by repeatedly imaging a 270 deg^2 area. Quasar candidates were selected from the deep data with good completeness over 0<z<5, and 2 to 3 magnitudes fainter than the SDSS main survey. Spectroscopic follow-up was carried out on the 6.5m MMT with Hectospec. The preliminary sample of this SDSS faint quasar survey (hereafter SFQS) covers ~ 3.9 deg^2, contains 414 quasars, and reaches g=22.5. The overall selection efficiency is ~ 66% (~ 80% at g<21.5); the efficiency in the most difficult redshift range (2<z<3) is better than 40%. We use the 1/V_{a} method to derive a binned estimate of the quasar luminosity function (QLF) and model the QLF using maximum likelihood analysis. The best model fits confirm previous results showing that the QLF has steep slopes at the bright end and much flatter slopes (-1.25 at z<2.0 and -1.55 at z>2.0) at the faint end, indicating a break in the QLF slope. Using a luminosity-dependent density evolution model, we find that the quasar density at M_{g}<-22.5 peaks at z~2, which is later in cosmic time than the peak of z~2.5 found from surveys of more luminous objects. The SFQS QLF is consistent with the results of the 2dF QSO Redshift Survey, the SDSS, and the 2dF-SDSS LRG and QSO Survey, but probes fainter quasars. We plan to obtain more quasars from future observations and establish a complete faint quasar sample with more than 1000 objects over 10 deg^2.Comment: 25 pages, 13 figures, accepted for publication in A

An exploration of parents’ preferences for foot care in juvenile idiopathic arthritis: a possible role for the discrete choice experiment

Background: An increased awareness of patients’ and parents’ care preferences regarding foot care is desirable from a clinical perspective as such information may be utilised to optimise care delivery. The aim of this study was to examine parents’ preferences for, and valuations of foot care and foot-related outcomes in juvenile idiopathic arthritis (JIA).&lt;p&gt;&lt;/p&gt; Methods: A discrete choice experiment (DCE) incorporating willingness-to-pay (WTP) questions was conducted by surveying 42 parents of children with JIA who were enrolled in a randomised-controlled trial of multidisciplinary foot care at a single UK paediatric rheumatology outpatients department. Attributes explored were: levels of pain; mobility; ability to perform activities of daily living (ADL); waiting time; referral route; and footwear. The DCE was administered at trial baseline. DCE data were analysed using a multinomial-logit-regression model to estimate preferences and relative importance of attributes of foot care. A stated-preference WTP question was presented to estimate parents’ monetary valuation of health and service improvements.&lt;p&gt;&lt;/p&gt; Results: Every attribute in the DCE was statistically significant (p &#60; 0.01) except that of cost (p = 0.118), suggesting that all attributes, except cost, have an impact on parents’ preferences for foot care for their child. The magnitudes of the coefficients indicate that the strength of preference for each attribute was (in descending order): improved ability to perform ADL, reductions in foot pain, improved mobility, improved ability to wear desired footwear, multidisciplinary foot care route, and reduced waiting time. Parents’ estimated mean annual WTP for a multidisciplinary foot care service was £1,119.05.&lt;p&gt;&lt;/p&gt; Conclusions: In terms of foot care service provision for children with JIA, parents appear to prefer improvements in health outcomes over non-health outcomes and service process attributes. Cost was relatively less important than other attributes suggesting that it does not appear to impact on parents’ preferences.&lt;p&gt;&lt;/p&gt

Dust-free quasars in the early Universe

The most distant quasars known, at redshifts z=6, generally have properties indistinguishable from those of lower-redshift quasars in the rest-frame ultraviolet/optical and X-ray bands. This puzzling result suggests that these distant quasars are evolved objects even though the Universe was only seven per cent of its current age at these redshifts. Recently one z=6 quasar was shown not to have any detectable emission from hot dust, but it was unclear whether that indicated different hot-dust properties at high redshift or if it is simply an outlier. Here we report the discovery of a second quasar without hot-dust emission in a sample of 21 z=6 quasars. Such apparently hot-dust-free quasars have no counterparts at low redshift. Moreover, we demonstrate that the hot-dust abundance in the 21 quasars builds up in tandem with the growth of the central black hole, whereas at low redshift it is almost independent of the black hole mass. Thus z=6 quasars are indeed at an early evolutionary stage, with rapid mass accretion and dust formation. The two hot-dust-free quasars are likely to be first-generation quasars born in dust-free environments and are too young to have formed a detectable amount of hot dust around them.Comment: To be published in Nature on the 18 March 2010

Tree modules and counting polynomials

We give a formula for counting tree modules for the quiver S_g with g loops and one vertex in terms of tree modules on its universal cover. This formula, along with work of Helleloid and Rodriguez-Villegas, is used to show that the number of d-dimensional tree modules for S_g is polynomial in g with the same degree and leading coefficient as the counting polynomial A_{S_g}(d, q) for absolutely indecomposables over F_q, evaluated at q=1.Comment: 11 pages, comments welcomed, v2: improvements in exposition and some details added to last sectio