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41.
Body condition may predict individual fitness because those in better condition have more resources to allocate towards improving their fitness. However, the hypothesis that condition indices are meaningful proxies for fitness has been questioned. Here, we ask if intraspecific variation in condition indices predicts annual reproductive success and survival. We monitored a population of Neochmia phaeton (crimson finch), a sedentary, tropical passerine, for reproductive success and survival over four breeding seasons, and sampled them for commonly used condition indices: mass adjusted for body size, muscle and fat scores, packed cell volume, hemoglobin concentration, total plasma protein, and heterophil to lymphocyte ratio. Our study population is well suited for this research because individuals forage in common areas and do not hold territories such that variation in condition between individuals is not confounded by differences in habitat quality. Furthermore, we controlled for factors that are known to impact condition indices in our study population (e.g., breeding stage) such that we assessed individual condition relative to others in the same context. Condition indices that reflect energy reserves predicted both the probability of an individual fledging young and the number of young produced that survived to independence, but only during some years. Those that were relatively heavy for their body size produced about three times more independent young compared to light individuals. That energy reserves are a meaningful predictor of reproductive success in a sedentary passerine supports the idea that energy reserves are at least sometimes predictors of fitness. However, hematological indices failed to predict reproductive success and none of the indices predicted survival. Therefore, some but not all condition indices may be informative, but because we found that most indices did not predict any component of fitness, we question the ubiquitous interpretation of condition indices as surrogates for individual quality and fitness. 相似文献
42.
The capacity of preformation and neoformation and the structure of winter buds are vegetative attributes that may vary between plant species and according to ontogenetic stages of the same species. The present study describes and evaluates these features for the four tree species of Proteaceae occurring in Patagonia. In particular, it analyzes the structure and development of the distal buds of the trunk and the preformed or neoformed nature of the organs involved. Two of the species, Embothrium coccineum and Lomatia hirsuta, have scaly buds, in which primordia of green leaves are covered by cataphylls. The shoots of both species may include neoformed organs, more frequently so in juvenile trees. Lomatia ferruginea and Gevuina avellana have naked buds with a low number of primordia; in juvenile and adult trees of both species trunk shoots are entirely preformed. The structure of buds and shoots suggests two different growth modalities of the axes, which would be related to ecological breadth (narrower in the species with naked buds than in those with scaly buds) and distribution area of these species. The considerable morphological differences between the two Lomatia species studied raise the question whether they ought to be included in the same genus. 相似文献
43.
James D. Nicholson Adam C. Puche Yan Guo Daniel Weinreich Bernard J. Slater Steven L. Bernstein 《PloS one》2012,7(12)
Few clinically effective approaches reduce CNS-white matter injury. After early in-vivo white matter infarct, NFκB-driven pro-inflammatory signals can amplify a relatively small amount of vascular damage, resulting in progressive endothelial dysfunction to create a severe ischemic lesion. This process can be minimized by 15-deoxy-Δ12,14-prostaglandin J2 (PGJ2), an analog of the metabolically active PGD2 metabolite. We evaluated PGJ2''s effects and mechanisms using rodent anterior ischemic optic neuropathy (rAION); an in vivo white matter ischemia model. PGJ2 administration systemically administered either acutely or 5 hours post-insult results in significant neuroprotection, with stereologic evaluation showing improved neuronal survival 30 days post-infarct. Quantitative capillary vascular analysis reveals that PGJ2 improves perfusion at 1 day post-infarct by reducing tissue edema. Our results suggest that PGJ2 acts by reducing NFκB signaling through preventing p65 nuclear localization and inhibiting inflammatory gene expression. Importantly, PGJ2 showed no in vivo toxicity structurally as measured by optic nerve (ON) myelin thickness, functionally by ON-compound action potentials, on a cellular basis by oligodendrocyte precursor survival or changes in ON-myelin gene expression. PGJ2 may be a clinically useful neuroprotective agent for ON and other CNS infarcts involving white matter, with mechanisms of action enabling effective treatment beyond the currently considered maximal time for intervention. 相似文献
44.
45.
Evidence for Involvement of an Electron Shuttle in Electricity Generation by Geothrix fermentans 总被引:2,自引:0,他引:2 下载免费PDF全文
In experiments performed using graphite electrodes poised by a potentiostat (+200 mV versus Ag/AgCl) or in a microbial fuel cell (with oxygen as the electron acceptor), the Fe(III)-reducing organism Geothrix fermentans conserved energy to support growth by coupling the complete oxidation of acetate to reduction of a graphite electrode. Other organic compounds, such as lactate, malate, propionate, and succinate as well as components of peptone and yeast extract, were utilized for electricity production. However, electrical characteristics and the results of shuttling assays indicated that unlike previously described electrode-reducing microorganisms, G. fermentans produced a compound that promoted electrode reduction. This is the first report of complete oxidation of organic compounds linked to electrode reduction by an isolate outside of the Proteobacteria. 相似文献
46.
Eight pilot-scale in-line filtration trials were performed to evaluate the passage of cyanobacterial cells through drinking water filters after sudden increases in hydraulic loading rates. Trials were performed at 30 °C using two coagulant combinations (aluminum sulfate and cationic polymer or ferric chloride and cationic polymer), two initial filter loading rates (7 or 10 m/h) and two species of morphologically different cyanobacteria (Microcystis aeruginosa or Anabaena flos aquae). The filter was perturbed by instantaneously increasing the hydraulic loading rate by 50%. Filter influent and effluent water qualities were characterized by measuring turbidity, particles and chlorophyll a. The observed post-perturbation filter effluent chlorophyll a peaks were 1.6–48 times greater than the pre-perturbation averages. Chlorophyll a peaks were larger for M. aeruginosa than for A. flos aquae. Chlorophyll a peaks were also larger for the higher (10 m/h) than for the lower (7 m/h) initial filter loading rate. The post-perturbation effluent turbidity peaks were 1.4–7.2 times greater than the pre-perturbation averages. The post-perturbation effluent particle peaks were 6.5–25 times greater than the pre-perturbation averages. These results indicate that particles were a more sensitive indicator of cyanobacterial passage than turbidity. 相似文献
47.
Tobias Consmüller Antonius Rohlmann Daniel Weinland Claudia Druschel Georg N. Duda William R. Taylor 《PloS one》2012,7(11)
The importance of functional parameters for evaluating the severity of low back pain is gaining clinical recognition, with evidence suggesting that the angular velocity of lordosis is critical for identification of musculoskeletal deficits. However, there is a lack of data regarding the range of functional kinematics (RoKs), particularly which include the changing shape and curvature of the spine. We address this deficit by characterising the angular velocity of lordosis throughout the thoracolumbar spine according to age and gender. The velocity of lumbar back shape changes was measured using Epionics SPINE during maximum flexion and extension activities in 429 asymptomatic volunteers. The difference between maximum positive and negative velocities represented the RoKs. The mean RoKs for flexion decreased with age; 114°/s (20–35 years), 100°/s (36–50 years) and 83°/s (51–75 years). For extension, the corresponding mean RoKs were 73°/s, 57°/s and 47°/s. ANCOVA analyses revealed that age and gender had the largest influence on the RoKs (p<0.05). The Epionics SPINE system allows the rapid assessment of functional kinematics in the lumbar spine. The results of this study now serve as normative data for comparison to patients with spinal pathology or after surgical treatment. 相似文献
48.
49.
Heat intolerance: does gene transcription contribute? 总被引:2,自引:0,他引:2
50.
A winter bloom dominated by Pseudo-nitzschia calliantha Lundholm, Moestrup et Hasle (Bacillariophyceae), a potential domoic acid producer, is reported for the first time in the Aegean Sea, Greece, in a semi-enclosed embayment (Kalloni Gulf) surrounded by agricultural land and drained by intermittent rivers. Abundances of this species in the inner part of the Gulf during February were extremely high (max 1.1 × 107 cells l−1). The species Alexandrium insuetum Balech (Dinophyceae) was also found in considerable cell numbers (max 1.4 × 105 cells l−1) during the bloom and reached up to 40% of the total biovolume. This study demonstrates an evident cause and effect relationship between nutrient inflows originating from agricultural activities in the watershed and the development of a potential HAB. The massive bloom formation was observed soon after an episodic rainfall event during the fertilizer application period (December to February). A bloom was also observed the following year, but it was less pronounced due to the fact that rainfalls were more evenly spaced in time and were of moderate intensity. 相似文献