4,265 research outputs found
Summer Ephemeroptera, Plecoptera, and Trichoptera (EPT) Species Richness and Community Structure in the Lower Illinois River Basin of Illinois
Ephemeroptera, Plecoptera, and Trichoptera (EPT) species richness is useful for monitoring stream health, but no published studies in Illinois quantitatively document EPT richness or assemblage structure. The objectives of this study were to characterize adult EPT richness and structure and relate these to relative water at eight stream sites (160-69,300 km3 area) in the lower Illinois River Adults were ultra-violet light trapped in June, July, and August 1997. Nutrient enrichment by nitrate and nitrite nitrogen was strongly evident, in smaller drainages, while critical loss of stable habitat was observed in water bodies. Seventy EPT species were identified from 17,889 specimens. Trichoptera were by far the most speciose (41 species), followed by Ephemeroptera (26), and Plecoptera (3). Caddisflies also dominated species richness across sites, contributing 18.0 of the average 28.9 total EPT species collected. Site EPT richness varied significantly (F =5.51, p 0.003, df 7), with smaller drainages supporting greater richness, generally. Differences were also evident for months (F = 21.7, p =0.0001, df =2), with June being lower (11.8 average) than either July (20.6) or August (18.1) values. Hilsenhoff biotic index (HBI) scores did not vary significantly across sites (F 0.7, p =0.7, df =7), but were different across months (F =5.4, p 0.02, df 2). June (4.23) and July (4.53) means were not different, but both were lower (of better quality) than August (5.33) scores. The relationship of EPT to HBI scores was not investigated statisti- cally due to problems of sample size and interdependance of monthly sam ples, but graphical analysis no consistent relationship. This sug- gested a decoupling of the the EPT and implied that the gain in taxonomic resolution achieved by adults outstripped the resolution of the HBI. Use of the HBI to characterize adult aquatic insect communities is discouraged. New state records and extensions for Ephemeroptera and Trichoptera are presented and loss of sensitive Plecoptera in the drainage is discussed
Systematic Reviews of University Programs and Units
Because universities in Canada, the U.S.A., and other Western countries are facing declining real income and increasing demands for greater accountability, they need to use resources more carefully and undertake planning activities more seriously. By obtaining information from reviews of academic and support units, universities are in a better position to meet these challenges. Most experts agree that reviews aimed at improvement of programs and activities are more successful when conducted under the authority of the university rather than an external agency. Attention needs to be paid to the establishment of an appropriate administrative mechanism that can maximize benefits relative to costs. This article describes the policies and procedures adopted in 1980 by The University of Alberta to allow for a continuous system of reviews of all academic and support units. Establishment of a President's Advisory Committee with a minimum of formal procedures has led to a successful system under which 51 units are now in various stages of the review process. The procedures used at The University of Alberta may be worthy of scrutiny by other universities contemplating such activity.u Canada, aux Etats-Unis et en d'autres pays occidentaux, les universités doivent faire face aux problèmes de la diminution de leurs revenus réels, des exigences en matière de comptes rendus plus satisfaisants de l'utilisation de leurs fonds et de la nécessité de faire de plus grands efforts de planification. Pour être plus en mesure de relever ces défis, les universités peuvent profiter des informations recueillies au cours des examens de l'état actuel de leurs unités académiques et de leurs services de soutien. La plupart des experts reconnaissant que de tels examens périodiques visant à l'amélioration des programmes et des activités connaissent un plus grand succès quand c 'est l'université elle-même qui les effectue plutôt qu 'un organisme externe quelconque. Il faut avoir grand soin de mettre au point un mécanisme administratif propre à apporter le maximum d'avantages par rapport aux coûts. Le présent article décrit la politique et les procédures adoptées en 1980 par l'Université de l'Alberta dans le but de faciliter un système permanent d'examen de l'état actuel de toutes ses unités académiques et de tous ses services de soutien. La mise sur pied d'un Comité consultatif du Recteur ayant le moins possible de procédures formelles a donné naissance à un système d'examen qui produit de bons résultats et grâce auquel 51 unités sont en voie d'être soumis d l'examen ou l'ont déjà été. Toute autre université qui envisage une telle entreprise aurait intérêt d étudier soigneuse-ment le système en vigueur à l'Université de l'Alberta
Summer Ephemeroptera, Plecoptera, and Trichoptera (EPT) Species Richness and Community Structure in the Lower Illinois River Basin of Illinois
Ephemeroptera, Plecoptera, and Trichoptera (EPT) species richness is useful for monitoring stream health, but no published studies in Illinois quantitatively document EPT richness or assemblage structure. The objectives of this study were to characterize adult EPT richness and structure and relate these to relative water at eight stream sites (160-69,300 km3 area) in the lower Illinois River Adults were ultra-violet light trapped in June, July, and August 1997. Nutrient enrichment by nitrate and nitrite nitrogen was strongly evident, in smaller drainages, while critical loss of stable habitat was observed in water bodies. Seventy EPT species were identified from 17,889 specimens. Trichoptera were by far the most speciose (41 species), followed by Ephemeroptera (26), and Plecoptera (3). Caddisflies also dominated species richness across sites, contributing 18.0 of the average 28.9 total EPT species collected. Site EPT richness varied significantly (F =5.51, p 0.003, df 7), with smaller drainages supporting greater richness, generally. Differences were also evident for months (F = 21.7, p =0.0001, df =2), with June being lower (11.8 average) than either July (20.6) or August (18.1) values. Hilsenhoff biotic index (HBI) scores did not vary significantly across sites (F 0.7, p =0.7, df =7), but were different across months (F =5.4, p 0.02, df 2). June (4.23) and July (4.53) means were not different, but both were lower (of better quality) than August (5.33) scores. The relationship of EPT to HBI scores was not investigated statisti- cally due to problems of sample size and interdependance of monthly sam ples, but graphical analysis no consistent relationship. This sug- gested a decoupling of the the EPT and implied that the gain in taxonomic resolution achieved by adults outstripped the resolution of the HBI. Use of the HBI to characterize adult aquatic insect communities is discouraged. New state records and extensions for Ephemeroptera and Trichoptera are presented and loss of sensitive Plecoptera in the drainage is discussed
Generalized LĂ©vy walks and the role of chemokines in migration of effector CD8+ T cells.
Chemokines have a central role in regulating processes essential to the immune function of T cells, such as their migration within lymphoid tissues and targeting of pathogens in sites of inflammation. Here we track T cells using multi-photon microscopy to demonstrate that the chemokine CXCL10 enhances the ability of CD8+ T cells to control the pathogen Toxoplasma gondii in the brains of chronically infected mice. This chemokine boosts T-cell function in two different ways: it maintains the effector T-cell population in the brain and speeds up the average migration speed without changing the nature of the walk statistics. Notably, these statistics are not Brownian; rather, CD8+ T-cell motility in the brain is well described by a generalized LĂ©vy walk. According to our model, this unexpected feature enables T cells to find rare targets with more than an order of magnitude more efficiency than Brownian random walkers. Thus, CD8+ T-cell behaviour is similar to LĂ©vy strategies reported in organisms ranging from mussels to marine predators and monkeys, and CXCL10 aids T cells in shortening the average time taken to find rare targets
The Hyaluronan Receptor for Endocytosis (HARE) Activates NF-κB-mediated Gene Expression in Response to 40–400-kDa, but Not Smaller or Larger, Hyaluronans
Background: HARE mediates systemic clearance of hyaluronan (HA), which turns over continuously in tissues.
Results: HARE uptake of 40–400-kDa, but not larger or smaller, HA stimulated NF-κB activation.
Conclusion: HA-HARE signal complexes activate NF-ÎşB and gene transcription only with optimally sized HA.
Significance: HARE responsiveness to a narrow size range ofHAdegradation products may be a sensing system to detect tissue ECM stress
Response to comment on "Human-specific gain of function in a developmental enhancer"
Duret and Galtier argue that human-specific sequence divergence and gain of function in the HACNS1 enhancer result from deleterious biased gene conversion (BGC) with no contribution from positive selection. We reinforce our previous conclusion by analyzing hypothesized BGC
events genomewide and assessing the effect of recombination rates on human-accelerated conserved noncoding sequence ascertainment. We also provide evidence that AT → GC substitution bias can coexist with positive selection
The Hyaluronan Receptor for Endocytosis (HARE) Activates NF-κB-mediated Gene Expression in Response to 40–400-kDa, but Not Smaller or Larger, Hyaluronans
Background: HARE mediates systemic clearance of hyaluronan (HA), which turns over continuously in tissues.
Results: HARE uptake of 40–400-kDa, but not larger or smaller, HA stimulated NF-κB activation.
Conclusion: HA-HARE signal complexes activate NF-ÎşB and gene transcription only with optimally sized HA.
Significance: HARE responsiveness to a narrow size range ofHAdegradation products may be a sensing system to detect tissue ECM stress
A Panel of Protein Kinase Chemosensors Distinguishes Different Types of Fatty Liver Disease
The worldwide incidence of fatty liver disease continues to rise, which may account for concurrent increases in the frequencies of more aggressive liver ailments. Given the existence of histologically identical fatty liver disease subtypes, there is a critical need for the identification of methods that can classify disease and potentially predict progression. Herein, we show that a panel of protein kinase chemosensors can distinguish fatty liver disease subtypes. These direct activity measurements highlight distinct differences between histologically identical fatty liver diseases arising from diets rich in fat versus alcohol and identify a previously unreported decrease in p38α activity associated with a high-fat diet. In addition, we have profiled kinase activities in both benign (dietinduced) and progressive (STAM) disease models. These experiments provide temporal insights into kinase activity during disease development and progression. Altogether, this work provides the basis for the future development of clinical diagnostics and potential treatment strategies
Ultra-Slow Light and Enhanced Nonlinear Optical Effects in a Coherently Driven Hot Atomic Gas
We report the observation of small group velocities of order 90 meters per
second, and large group delays of greater than 0.26 ms, in an optically dense
hot rubidium gas (~360 K). Media of this kind yield strong nonlinear
interactions between very weak optical fields, and very sharp spectral
features. The result is in agreement with previous studies on nonlinear
spectroscopy of dense coherent media
Chronic alcohol exposure alters circulating insulin and ghrelin levels: role of ghrelin in hepatic steatosis
Fatty liver is the earliest response of the liver to excessive ethanol consumption. Central in the development of alcoholic steatosis is increased mobilization of nonesterified free fatty acids (NEFAs) to the liver from the adipose tissue. In this study, we hypothesized that ethanol-induced increase in ghrelin by impairing insulin secretion, could be responsible for the altered lipid metabolism observed in adipose and liver tissue. Male Wistar rats were fed for 5–8 wk with control or ethanol Lieber-DeCarli diet, followed by biochemical analyses in serum and liver tissues. In addition, in vitro studies were conducted on pancreatic islets isolated from experimental rats. We found that ethanol increased serum ghrelin and decreased serum insulin levels in both fed and fasting conditions. These results were corroborated by our observations of a significant accumulation of insulin in pancreatic islets of ethanol-fed rats, indicating that its secretion was impaired. Furthermore, ethanol-induced reduction in circulating insulin was associated with lower adipose weight and increased NEFA levels observed in these rats. Additionally, we found that increased concentration of serum ghrelin was due to increased synthesis and maturation in the stomach of the ethanol-fed rats. We also report that in addition to its effect on the pancreas, ghrelin can also directly act on hepatocytes via the ghrelin receptors and promote fat accumulation. In conclusion, alcohol-induced elevation of circulating ghrelin levels impairs insulin secretion. Consequently, reduced circulating insulin levels likely contribute to increased free fatty acid mobilization from adipose tissue to liver, thereby contributing to hepatic steatosis
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