557 research outputs found
New Genus and Species of Aporocotylidae (Digenea) from a Basal Actinopterygian, the American Paddlefish, Polyodon spathula, (Acipenseriformes: Polyodontidae) from the Mississippi Delta
Acipensericola petersoni n. gen., n. sp. (Digenea: Aporocotylidae) infects the heart of the American paddlefish Polyodon spathula (Walbaum, 1792) in the Mississippi Delta. It has robust, spike-like body spines arranged in ventrolateral transverse rows; a bowl-shaped anterior sucker centered on the mouth and having minute spines on the inner anteroventral surface only; a pharynx; an inverse U-shaped ceca extending to near the posterior body end; intercecal testes comprising a pre-ovarian testicular column plus a single testis posteriorly; an extensively lobed ovary located medially and immediately posterior to the testicular column; a spherical ootype that is intercecal and post-ovarian; a Laurer’s canal; and a common genital pore. The new species is the first-named aporocotylid collected from a basal actinopterygian. It resembles the chondrichthyan aporocotylids Chimaerohemecus trondheimensis, Orchispirium heterovitellatum, and Hyperandrotrema cetorhini in having an inverse U-shaped ceca, but it is morphologically most similar to the anguilliform aporocotylid Paracardicoloides yamagutii in having that feature plus a comparable anterior sucker, a single testis posteriorly, an intertesticular ovary, and a common genital pore. Sequence data for the complete small subunit ribosomal DNA (18S) do not refute its membership within Aporocotylidae nor its affinity to 1 of those aforementioned aporocotylids: A. petersoni was basal to the few teleost aporocotylids analyzed, and C. trondheimensis was the only taxon basal to A. petersoni. We regard the specimens of Spirorchis sp. previously reported from the shortnose sturgeon Acipenser brevirostrum Lesueur, 1818 as congeneric with the new species
Environmentally friendly and sustainable bark cloth for garment applications: Evaluation of fabric properties and apparel development
Ugandan bark cloth has been recognised by UNESCO as a masterpiece of the ‘Intangible Cultural Heritage of Humanity’, to protect the knowledge, traditions and livelihoods associated with its production. Bark cloth is a non-woven, fibrous textile that has been produced from the wild fig or mutuba tree (Ficus natalensis) by the Baganda people of southern Uganda for hundreds of years. A typical bark cloth has a rich, terracotta colour and is worn by kings and chiefs during coronations, religious ceremonies and cultural gatherings, as well as for funeral shrouds. Due to the growing awareness and the need to reduce the environmental impact of textiles, there is a pressing rationale to use natural materials or fibres in fashion clothing in recent years as designers and practitioners embrace environmentally sustainable raw materials and promote traditional craftsmanship. Various properties and significance of bark cloth from cultural, ethical, technical and aesthetic perspectives to determine its feasibility as a sustainable fashion textile was explored. The potential of bark cloth specifically in relation to the characteristics of luxury fashion (craftsmanship, quality, rarity, heritage and storytelling), through using techniques that include embroidery, appliqué, gilding, laser cutting, natural dyeing and fusing is highlighted. The bark cloth was investigated for its practical suitability for apparel end use. Various fabric tests were conducted to determine its performance including fabric drape, stiffness, surface morphology, and tearing strength. The bark cloth was subjected to CO2 laser etching and sublimation printing to incorporate surface patterns and attenuated total reflectance Fourier transform infrared spectroscopy [ATR-FTIR] was used to monitor the loss of fibres. Based on the trials, an optimum set of parameters were identified to use laser and sublimation printing. Raw bark cloth was stiff when heat-pressed, so it was fused with various fusible interfacing fabrics [A,B, and C] to enhance drape, texture, handle and strength. Results indicated that bark cloth when fused with woven interfacing [C] improved its strength [warp direction aligned with fabric grain] by approximately six times [330 N] the strength of bark cloth [57 N]. Fabric drape increased marginally [1.0–3.0%] when fusing with the interfacing, however it offered better handle when making the garment. A basic test garment (size 12 female full-sleeve top) was developed with the fused bark cloth that offered good drape and its shape and fit were evaluated on a mannequin. Outcomes indicated that bark cloth could be satisfactorily developed into outer garments with specific treatment
Identification of intraneuronal amyloid beta oligomers in locus coeruleus neurons of Alzheimer's patients and their potential impact on inhibitory neurotransmitter receptors and neuronal excitability
The author's final peer reviewed version can be found by following the URI link. The Publisher's final version can be found by following the DOI link.Aims Amyloid β oligomers (AβO) are potent modulators of Alzheimer’s pathology, yet their impact on one of the earliest brain regions to exhibit signs of the condition, the locus coeruleus (LC), remains to be determined. Of particular importance is whether AβO impact the spontaneous excitability of LC neurons. This parameter determines brain‐wide noradrenaline (NA) release, and thus NA‐mediated brain functions, including cognition, emotion and immune function, which are all compromised in Alzheimer’s. Therefore, the aim of the study was to determine the expression profile of AβO in the LC of Alzheimer’s patients and to probe their potential impact on the molecular and functional correlates of LC excitability, using a mouse model of increased Aβ production (APP‐PSEN1). Methods and Results Immunohistochemistry and confocal microscopy, using AβO‐specific antibodies, confirmed LC AβO expression both intraneuronally and extracellularly in both Alzheimer’s and APP‐PSEN1 samples. Patch clamp electrophysiology recordings revealed that APP‐PSEN1 LC neuronal hyperexcitability accompanied this AβO expression profile, arising from a diminished inhibitory effect of GABA, due to impaired expression and function of the GABA‐A receptor (GABAAR) α3 subunit. This altered LC α3‐GABAAR expression profile overlapped with AβO expression in samples from both APP‐PSEN1 mice and Alzheimer’s patients. Finally, strychnine‐sensitive glycine receptors (GlyRs) remained resilient to Aβ‐induced changes and their activation reversed LC hyperexcitability. Conclusions The data suggest a close association between AβO and α3‐GABAARs in the LC of Alzheimer’s patients, and their potential to dysregulate LC activity, thereby contributing to the spectrum of pathology of the LC‐NA system in this condition
What Brown saw and you can too
A discussion is given of Robert Brown's original observations of particles
ejected by pollen of the plant \textit{Clarkia pulchella} undergoing what is
now called Brownian motion. We consider the nature of those particles, and how
he misinterpreted the Airy disc of the smallest particles to be universal
organic building blocks. Relevant qualitative and quantitative investigations
with a modern microscope and with a "homemade" single lens microscope similar
to Brown's, are presented.Comment: 14.1 pages, 11 figures, to be published in the American Journal of
Physics. This differs from the previous version only in the web site referred
to in reference 3. Today, this Brownian motion web site was launched, and
http://physerver.hamilton.edu/Research/Brownian/index.html, is now correc
Learning to Obtain Reward, but Not Avoid Punishment, Is Affected by Presence of PTSD Symptoms in Male Veterans: Empirical Data and Computational Model
Post-traumatic stress disorder (PTSD) symptoms include behavioral avoidance which is acquired and tends to increase with time. This avoidance may represent a general learning bias; indeed, individuals with PTSD are often faster than controls on acquiring conditioned responses based on physiologically-aversive feedback. However, it is not clear whether this learning bias extends to cognitive feedback, or to learning from both reward and punishment. Here, male veterans with self-reported current, severe PTSD symptoms (PTSS group) or with few or no PTSD symptoms (control group) completed a probabilistic classification task that included both reward-based and punishment-based trials, where feedback could take the form of reward, punishment, or an ambiguous “no-feedback” outcome that could signal either successful avoidance of punishment or failure to obtain reward. The PTSS group outperformed the control group in total points obtained; the PTSS group specifically performed better than the control group on reward-based trials, with no difference on punishment-based trials. To better understand possible mechanisms underlying observed performance, we used a reinforcement learning model of the task, and applied maximum likelihood estimation techniques to derive estimated parameters describing individual participants’ behavior. Estimations of the reinforcement value of the no-feedback outcome were significantly greater in the control group than the PTSS group, suggesting that the control group was more likely to value this outcome as positively reinforcing (i.e., signaling successful avoidance of punishment). This is consistent with the control group’s generally poorer performance on reward trials, where reward feedback was to be obtained in preference to the no-feedback outcome. Differences in the interpretation of ambiguous feedback may contribute to the facilitated reinforcement learning often observed in PTSD patients, and may in turn provide new insight into how pathological behaviors are acquired and maintained in PTSD
Free and self-interacting scalar fields in the presence of conical singularities
Free and self-interacting scalar fields in the presence of conical
singularities are analized in some detail. The role of such a kind of
singularities on free and vacuum energy and also on the one-loop effective
action is pointed out using -function regularization and heat-kernel
techniques.Comment: 20 Pages, RevTex, UTF30
Species-Specific Responses of Juvenile Rockfish to Elevated pCO2: From Behavior to Genomics
In the California Current ecosystem, global climate change is predicted to trigger large-scale changes in ocean chemistry within this century. Ocean acidification—which occurs when increased levels of atmospheric CO2 dissolve into the ocean—is one of the biggest potential threats to marine life. In a coastal upwelling system, we compared the effects of chronic exposure to low pH (elevated pCO2) at four treatment levels (i.e., pCO2 = ambient [500], moderate [750], high [1900], and extreme [2800 μatm]) on behavior, physiology, and patterns of gene expression in white muscle tissue of juvenile rockfish (genus Sebastes), integrating responses from the transcriptome to the whole organism level. Experiments were conducted simultaneously on two closely related species that both inhabit kelp forests, yet differ in early life history traits, to compare high-CO2 tolerance among species. Our findings indicate that these congeners express different sensitivities to elevated CO2 levels. Copper rockfish (S. caurinus) exhibited changes in behavioral lateralization, reduced critical swimming speed, depressed aerobic scope, changes in metabolic enzyme activity, and increases in the expression of transcription factors and regulatory genes at high pCO2 exposure. Blue rockfish (S. mystinus), in contrast, showed no significant changes in behavior, swimming physiology, or aerobic capacity, but did exhibit significant changes in the expression of muscle structural genes as a function of pCO2, indicating acclimatization potential. The capacity of long-lived, late to mature, commercially important fish to acclimatize and adapt to changing ocean chemistry over the next 50–100 years is likely dependent on species-specific physiological tolerances
Evaluation Research and Institutional Pressures: Challenges in Public-Nonprofit Contracting
This article examines the connection between program evaluation research and decision-making by public managers. Drawing on neo-institutional theory, a framework is presented for diagnosing the pressures and conditions that lead alternatively toward or away the rational use of evaluation research. Three cases of public-nonprofit contracting for the delivery of major programs are presented to clarify the way coercive, mimetic, and normative pressures interfere with a sound connection being made between research and implementation. The article concludes by considering how public managers can respond to the isomorphic pressures in their environment that make it hard to act on data relating to program performance.This publication is Hauser Center Working Paper No. 23. The Hauser Center Working Paper Series was launched during the summer of 2000. The Series enables the Hauser Center to share with a broad audience important works-in-progress written by Hauser Center scholars and researchers
HIV Gag mimics the Tsg101-recruiting activity of the human Hrs protein
The HIV-1 Gag protein recruits the cellular factor Tsg101 to facilitate the final stages of virus budding. A conserved P(S/T)AP tetrapeptide motif within Gag (the “late domain”) binds directly to the NH2-terminal ubiquitin E2 variant (UEV) domain of Tsg101. In the cell, Tsg101 is required for biogenesis of vesicles that bud into the lumen of late endosomal compartments called multivesicular bodies (MVBs). However, the mechanism by which Tsg101 is recruited from the cytoplasm onto the endosomal membrane has not been known. Now, we report that Tsg101 binds the COOH-terminal region of the endosomal protein hepatocyte growth factor–regulated tyrosine kinase substrate (Hrs; residues 222–777). This interaction is mediated, in part, by binding of the Tsg101 UEV domain to the Hrs 348PSAP351 motif. Importantly, Hrs222–777 can recruit Tsg101 and rescue the budding of virus-like Gag particles that are missing native late domains. These observations indicate that Hrs normally functions to recruit Tsg101 to the endosomal membrane. HIV-1 Gag apparently mimics this Hrs activity, and thereby usurps Tsg101 and other components of the MVB vesicle fission machinery to facilitate viral budding
- …