6,791 research outputs found
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Geographic variation and evolutionary history of Dipodomys nitratoides (Rodentia: Heteromyidae), a species in severe decline
We examined geographic patterns of diversification in the highly impacted San Joaquin kangaroo rat, Dipodomys nitratoides, throughout its range in the San Joaquin Valley and adjacent basins in central California. The currently recognized subspecies were distinct by the original set of mensural and color variables used in their formal diagnoses, although the Fresno kangaroo rat (D. n. exilis) is the most strongly differentiated with sharp steps in character clines relative to the adjacent Tipton (D. n. nitratoides) and short-nosed (D. n. brevinasus) races. The latter two grade more smoothly into one another but still exhibit independent, and different, character clines within themselves. At the molecular level, as delineated by mtDNA cytochrome b sequences, most population samples retain high levels of diversity despite significant retraction in the species range and severe fragmentation of local populations in recent decades due primarily to landscape conversion for agriculture and secondarily to increased urbanization. Haplotype apportionment bears no relationship to morphologically defined subspecies boundaries. Rather, a haplotype network is shallow, most haplotypes are single-step variants, and the time to coalescence is substantially more recent than the time of species split between D. nitratoides and its sister taxon, D. merriami. The biogeographic history of the species within the San Joaquin Valley appears tied to mid-late Pleistocene expansion following significant drying of the valley resulting from the rain shadow produced by uplift of the Central Coastal Ranges
Smoke-Free Men: Competing and Connecting to Quit.
PURPOSE: The purpose of this study was to explore gender-related factors that motivate and support men's smoking reduction and cessation to inform effective men-centered interventions. Approach or Design: Focus group design using a semi-structured interview guide. SETTING: Three communities in British Columbia, Canada. PARTICIPANTS: A total of 56 men who currently smoked and were interested in reducing or quitting or had quit. INTERVENTION: N/A. METHODS: Data collected in 6 focus group discussions were transcribed and analyzed in accord with principles of thematic qualitative methods. RESULTS: We report the results across 4 interconnected themes: (1) the fight to quit takes several rounds, (2) the motivation of supportive competition, (3) challenges and benefits of connecting with smoke-free peers, and (4) playing up the physical and financial gains. CONCLUSIONS: Masculine-based perspectives positioned quitting alongside fighting for self-control, competing, connecting, physical prowess, and having extra cash as motivating components of programs to engage men in efforts to be smoke-free. It may be worthwhile to consider the inclusion of gain-framed and benefit-focused messaging in programs that support men's tobacco cessation
A clinically relevant in vivo model for the assessment of scaffold efficacy in abdominal wall reconstruction
Copyright © The Author(s) 2017. An animal model that allows for assessment of the degree of stretching or contraction of the implant area and the in vivo degradation properties of biological meshes is required to evaluate their performance in vivo. Adult New Zealand rabbits underwent full thickness subtotal unilateral rectus abdominis muscle excision and were reconstructed with the non-biodegradable Peri-Guard®, Prolene® or biodegradable Surgisis® meshes. Following 8 weeks of recovery, the anterior abdominal wall tissue samples were collected for measurement of the implant dimensions. The Peri-Guard and Prolene meshes showed a slight and obvious shrinkage, respectively, whereas the Surgisis mesh showed stretching, resulting in hernia formation. Surgisis meshes showed in vivo biodegradation and increased collagen formation. This surgical rabbit model for abdominal wall defects is advantageous for evaluating the in vivo behaviour of surgical meshes. Implant area stretching and shrinkage were detected corresponding to mesh properties, and histological analysis and stereological methods supported these findings.This study was financially supported by the Enterprise Ireland (Technology Development Grant). This publication has emanated from research conducted with the financial support of Science Foundation Ireland (SFI) and is co-funded under the European Regional Development Fund under grant no. 13/RC/2073. This study was also supported by the Centre for Microscopy & Imaging funded by NUI Galway and PRTLI, Cycles 4 and 5, National Development Plan 2007–2013
Manipulation of both virus- and cell-specific factors is required for robust transient replication of a hepatitis C virus genotype 3a sub-genomic replicon
Hepatitis C virus (HCV) genotype (GT) 3 is the second most prevalent of the seven HCV genotypes and exhibits the greatest resistance to the highly potent, direct-acting antivirals (DAAs) that are currently in use. Previously a stable cell line harbouring the S52 GT3 subgenomic replicon (SGR) was established, but this SGR was unable to robustly replicate transiently. As transient SGRs are a critical tool in the development of DAAs, and the study of viral resistance, we sought to establish a transient SGR system based on S52. Next generation sequencing was used to identify putative culture-adaptive substitutions that had arisen during long term selection of the S52 SGR. A subset of these substitutions were built back into the S52 SGR in the context of a CpG/UpA-low luciferase reporter, with a single point mutation in NS4A conferring the greatest replication capability upon S52. Modification of the innate immune-sensing pathways of Huh7.5 hepatoma cells by expression of the parainfluenza virus type 5 V protein and SEC14L2 resulted in a further enhancement of S52 replication. Furthermore, this transiently-replicating SGR showed genotype-specific differences in sensitivity to two clinically-relevant NS5A DAAs. In conclusion, we report that a single substitution in NS4A, coupled with host cell modifications, enabled robust levels of transient replication by the GT3 S52 SGR. This system will have beneficial uses in both basic research into the unique aspects of GT3 biology and drug discovery
An Electrocorticographic Brain Interface in an Individual with Tetraplegia
Brain-computer interface (BCI) technology aims to help individuals with disability to control assistive devices and reanimate paralyzed limbs. Our study investigated the feasibility of an electrocorticography (ECoG)-based BCI system in an individual with tetraplegia caused by C4 level spinal cord injury. ECoG signals were recorded with a high-density 32-electrode grid over the hand and arm area of the left sensorimotor cortex. The participant was able to voluntarily activate his sensorimotor cortex using attempted movements, with distinct cortical activity patterns for different segments of the upper limb. Using only brain activity, the participant achieved robust control of 3D cursor movement. The ECoG grid was explanted 28 days post-implantation with no adverse effect. This study demonstrates that ECoG signals recorded from the sensorimotor cortex can be used for real-time device control in paralyzed individuals
Weighted entropy and optimal portfolios for risk-averse Kelly investments
Following a series of works on capital growth investment, we analyse
log-optimal portfolios where the return evaluation includes `weights' of
different outcomes. The results are twofold: (A) under certain conditions, the
logarithmic growth rate leads to a supermartingale, and (B) the optimal
(martingale) investment strategy is a proportional betting. We focus on
properties of the optimal portfolios and discuss a number of simple examples
extending the well-known Kelly betting scheme.
An important restriction is that the investment does not exceed the current
capital value and allows the trader to cover the worst possible losses.
The paper deals with a class of discrete-time models. A continuous-time
extension is a topic of an ongoing study
Assessment of anxiety in children and adolescents: A comparative study on the validity and reliability of the Spence Children's Anxiety Scale in children and adolescents with anxiety and Autism Spectrum Disorder
Objective: The present study assessed the utility of the Spence Children's Anxiety Scale - Parent Form (SCAS-P) across parents of children with (i) anxiety and (ii) Autism Spectrum Disorder (ASD). Method: Parents of children aged 7–18 years with anxiety or ASD completed the SCAS-P. Multiple indicator multiple cause (MIMIC) structural equation modelling was utilized to analyse the data. Results: Analysis revealed different factor structures between the Anxious and ASD groups and evidence for measurement variance across groups in some parts of the SCAS-P. Conclusion: Results on the SCAS-P in children with ASD need to be interpreted with caution. Some SCAS-P items cannot be interpreted in the same way in an ASD population compared to neurotypical children with anxiety
Depression and Prostate Cancer: Examining Comorbidity and Male-Specific Symptoms
© The Author(s) 2018. Depression in men with prostate cancer is a significant and complex issue that can challenge clinicians’ diagnostic efforts. The objective of the current study was to evaluate prototypic and male-specific depression symptoms and suicidal ideation in men with a diagnosis of prostate cancer relative to those with and without comorbidity. The Patient Health Questionnaire-9 (PHQ-9) and Male Depression Risk Scale-22 (MDRS-22) were completed online along with demographic and background variables by 100 men with a diagnosis of prostate cancer (n = 54 prostatectomy, n = 33 receiving active treatment). Hierarchical logistic regression was used to examine recent (past 2 weeks) suicide ideation. Over one-third of the sample (38%) reported a comorbidity, and this group had significantly higher total depression scores on the PHQ-9 (Cohen’s d = 0.65), MDRS-22 emotion suppression (d = 0.35), and drug use subscales (d = 0.38) compared to respondents without comorbidity. A total of 14% reported recent suicidal ideation, of which 71.4% of cases were identified by the PHQ-9 “moderate” cut-off, and 85.7% of cases were identified by the MDRS-22 “elevated” cut-off. After control variables, MDRS-22 subscales accounted for 45.1% of variance in recent suicidal ideation. While limited by the exclusive use of self-report data, findings point to the potential benefits of evaluating male-specific symptoms as part of depression and suicide risk screening in men with prostate cancer and the need to be mindful of the heightened risk for depression among men with prostate cancer who have comorbidity
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Thorium Energy Futures
The potential for thorium as an alternative or supplement to uranium in fission power generation has long been recognised, and several reactors, of various types, have already operated using thorium-based fuels. Accelerator Driven Subcritical (ADS) systems have benefits and drawbacks when compared to conventional critical thorium reactors, for both solid and molten salt fuels. None of the four options – liquid or solid, with or without an accelerator – can yet be rated as better or worse than the other three, given today's knowledge. We outline the research that will be necessary to lead to an informed choice
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