Illusions of gunk

The possibility of gunk has been used to argue against mereological nihilism. This paper explores two responses on the part of the microphysical mereological nihilist: (1) the contingency defence, which maintains that nihilism is true of the actual world; but that at other worlds, composition occurs; (2) the impossibility defence, which maintains that nihilism is necessary true, and so gunk worlds are impossible. The former is argued to be ultimately unstable; the latter faces the explanatorily burden of explaining the illusion that gunk is possible. It is argued that we can discharge this burden by focussing on the contingency of the microphysicalist aspect of microphysical mereological nihilism. The upshot is that gunk-based arguments against microphysical mereological nihilism can be resisted

Diamonds are Forever

We defend the thesis that every necessarily true proposition is always true. Since not every proposition that is always true is necessarily true, our thesis is at odds with theories of modality and time, such as those of Kit Fine and David Kaplan, which posit a fundamental symmetry between modal and tense operators. According to such theories, just as it is a contingent matter what is true at a given time, it is likewise a temporary matter what is true at a given possible world; so a proposition that is now true at all worlds, and thus necessarily true, may yet at some past or future time be false in the actual world, and thus not always true. We reconstruct and criticize several lines of argument in favor of this picture, and then argue against the picture on the grounds that it is inconsistent with certain sorts of contingency in the structure of time

Kinetics and roles of individual TNF receptors in models of acute lung injury in mice

Mechanical ventilation, essential for the support of patients with acute lung injury (ALI), causes exacerbation of the existing pathology, a process termed ventilator-induced lung injury (VILI). The pro-inflammatory cytokine tumour necrosis factor-alpha (TNF) has been consistently implicated in ALI/VILI. TNF activates two receptors, TNFR p55 and p75 that act in opposition during VILI to promote or protect against pulmonary oedema formation, respectively, but the mechanisms underlying this are unknown. Alveolar and plasma soluble TNFR (sTNFR) levels are elevated in ventilated ALI patients and associated with mortality. However, the relevance of these increases is unclear. This project had two main aims: to investigate kinetics and sources of sTNFRs in the alveoli and plasma and investigate mechanisms underlying differential TNFR signalling during VILI, using in vivo mouse models. Investigation of intraalveolar sTNFRs during VILI, and also ALI induced by intratracheal administration of hydrochloric acid or bacterial toxins, showed that intraalveolar sTNFRs are differentially regulated during ALI: VILI/hydrochloric acid induced leakage of sTNFR p55 and p75 from plasma, whereas bacterial toxins induced intraalveolar p75 production. These differences have important implications for TNF signalling and potential use as clinical markers. Investigation of plasma sTNFRs suggests that VILI induces direct production of sTNFRs by the pulmonary vasculature, as opposed to leakage of intraalveolar sTNFRs into the circulation as previously suggested. Development of a flow cytometry technique to study pulmonary TNFR expression was successfully validated using TNFR deficient tissue, but consolidation of data by immunohistochemistry was unsuccessful. Investigation of differential TNFR signalling mechanisms showed that following intratracheal fluid administration, p75 deficient mice exhibit physiological changes consistent with impaired fluid reabsorption, implicating p75 in lung fluid reabsorption during VILI. These data offer new, potentially clinically applicable insights into the involvement of TNFR biology in VILI/ALI and the novel methodologies developed herein constitute useful tools for future research

Enhanced learning performance in the middle school classroom through increased student motivation, by the use of educational software and question-based gaming technology.

The purpose of this research was to determine if the introduction of a competitive and collaborative computer-based gaming software system into middle school classrooms would result in improved attendance and grades, and motivate students to have a greater interest in their studies. This study was conducted over a 6 week period, with attendance and performance data being collected from 284 students. Two quantitative surveys were used to measure course interest and motivation: (a) the Course Interest Survey (CIS), and (b) the Instructional Materials Motivation Survey (IMMS). Participation in these surveys consisted of 84 students taking the CIS and 40 students taking the IMMS. The results indicated that the experimental group showed statistically better scores than the comparison group in attendance and performance. Students participating in the experimental group had significantly lower mean ranks of absenteeism compared to students in the comparison group. Results also revealed significant differences on grades. Students that were in the experimental group had significantly higher grades compared to students that were in the comparison group. Results of the CIS suggest that a statistically significant difference does not exist on Attention, Relevance, Confidence, and Satisfaction between the experimental and comparison groups. Results of the means and standard deviations for the IMMS Motivation Scores fell somewhere between Moderately true and Mostly true. This research study suggests that student's attendance and performance can be improved when quiz based gaming software that is both collaborative and competitive is used regularly in the classroom. However, for student's that participated in the gaming software, their interest in studying the subject doesn't appear to be significantly different from students that did not participate

What's on TV? Detecting age-related neurodegenerative eye disease using eye movement scanpaths

Purpose: We test the hypothesis that age-related neurodegenerative eye disease can be detected by examining patterns of eye movement recorded whilst a person naturally watches a movie. Methods: Thirty-two elderly people with healthy vision (median age: 70, interquartile range [IQR] 64–75 years) and 44 patients with a clinical diagnosis of glaucoma (median age: 69, IQR 63–77 years) had standard vision examinations including automated perimetry. Disease severity was measured using a standard clinical measure (visual field mean deviation; MD). All study participants viewed three unmodified TV and film clips on a computer set up incorporating the Eyelink 1000 eyetracker (SR Research, Ontario, Canada). Eye movement scanpaths were plotted using novel methods that first filtered the data and then generated saccade density maps. Maps were then subjected to a feature extraction analysis using kernel principal component analysis (KPCA). Features from the KPCA were then classified using a standard machine based classifier trained and tested by a 10-fold cross validation which was repeated 100 times to estimate the confidence interval (CI) of classification sensitivity and specificity. Results: Patients had a range of disease severity from early to advanced (median [IQR] right eye and left eye MD was −7 [−13 to −5] dB and −9 [−15 to −4] dB, respectively). Average sensitivity for correctly identifying a glaucoma patient at a fixed specificity of 90% was 79% (95% CI: 58–86%). The area under the Receiver Operating Characteristic curve was 0.84 (95% CI: 0.82–0.87). Conclusions: Huge data from scanpaths of eye movements recorded whilst people freely watch TV type films can be processed into maps that contain a signature of vision loss. In this proof of principle study we have demonstrated that a group of patients with age-related neurodegenerative eye disease can be reasonably well separated from a group of healthy peers by considering these eye movement signatures alone

Economic Losses of Catfish to Avian Predation: A Case Report

Avian predation in catfish aquaculture has been a persistent issue throughout the history of the industry, and as production has expanded predation from piscivorous birds has intensified. Catfish ponds in the Mississippi River delta (in the Mississippi migratory flyway) provide a constant and readily accessible supply of forage for birds. Intensive foraging by fish-eating birds has led to a specific regulatory policy and numerous on-farm and regional management efforts. However, in 2016, legal challenges lead to recision of some federal policies and uncertainty as to allowable management, resulting in limitations on bird depredation. Estimating the extent of fish losses to avian predators is difficult, as loss estimates from farms are often confounded with disease- and management-related mortalities. This study details the reported losses to birds that were observed in commercial-scale catfish ponds at the Thad Cochran National Warmwater Aquaculture Center, Stoneville, Mississippi, during periods of limited bird management. The observed fish losses attributed to birds ranged from 33% to 95% loss in survival and potential yield losses of 4,396 to 8,889 lb/acre, increasing production costs and decreasing net returns. Net economic losses when accounting for negative net returns and lost profits ranged from US$3,518 to$4,060/acre. Losses of this magnitude on commercial fish farms are economically detrimental, especially because catfish farms lack the compensatory economic relief programs that are available in other agriculture sectors. Roost dispersal activities that are organized by federal agencies and avoiding delays in issuing bird depredation permits are vital for mitigating this persistent and growing regulatory problem in the U.S. catfish industry

Segmentation of the C57BL/6J mouse cerebellum in magnetic resonance images

The C57BL mouse is the centerpiece of efforts to use gene-targeting technology to understand cerebellar pathology, thus creating a need for a detailed magnetic resonance imaging (MRI) atlas of the cerebellum of this strain. In this study we present a methodology for systematic delineation of the vermal and hemispheric lobules of the C57BL/6J mouse cerebellum in magnetic resonance images. We have successfully delineated 38 cerebellar and cerebellar-related structures. The higher signal-to-noise ratio achieved by group averaging facilitated the identification of anatomical structures. In addition, we have calculated average region volumes and created probabilistic maps for each structure. The segmentation method and the probabilistic maps we have created will provide a foundation for future studies of cerebellar disorders using transgenic mouse models

Visualization of mouse barrel cortex using ex-vivo track density imaging

We describe the visualization of the barrel cortex of the primary somatosensory area (S1) of ex vivo adult mouse brain with short-tracks track density imaging (stTDI). stTDI produced much higher definition of barrel structures than conventional fractional anisotropy (FA), directionally-encoded color FA maps, spin-echo and T2-weighted imaging and gradient echo Ti/T2*-weighted imaging. 3D high angular resolution diffusion imaging (HARDI) data were acquired at 48 micron isotropic resolution for a (3 mm)3 block of cortex containing the barrel field and reconstructed using stTDI at 10 micron isotropic resolution. HARDI data were also acquired at 100 micron isotropic resolution to image the whole brain and reconstructed using stTDI at 20 micron isotropic resolution. The 10 micron resolution stTDI maps showed exceptionally clear delineation of barrel structures. Individual barrels could also be distinguished in the 20 micron stTDI maps but the septa separating the individual barrels appeared thicker compared to the 10 micron maps, indicating that the ability of stTDI to produce high quality structural delineation is dependent upon acquisition resolution. Close homology was observed between the barrel structure delineated using stTDI and reconstructed histological data from the same samples. stTDI also detects barrel deletions in the posterior medial barrel sub-field in mice with infraorbital nerve cuts. The results demonstrate that stTDI is a novel imaging technique that enables three-dimensional characterization of complex structures such as the barrels in S1 and provides an important complementary non-invasive imaging tool for studying synaptic connectivity, development and plasticity of the sensory system. (C) 2013 Elsevier Inc. All rights reserved