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871.
The main objective of this study was to investigate the population structure, length–weight relationship (LWR) and growth of white seabream, Diplodus sargus sargus (L., 1758) in Beymelek Lagoon, Turkey. Samples were collected by gill‐ and trammel nets of various mesh sizes, February 2006 to January 2007. A total of 355 specimens (51 males; 34 females; 270 unidentified) were collected. Male to female ratio was 1.50 : 1. Ages ranged from 0 to 3 years; about 70% were juveniles. Most fish were between 13 and 16 cm in total length and below 90 g in weight. The LWR of all individuals was W = 0.0140 × L3.1028. The von Bertalanffy growth equation was calculated as Lt = 39.9 × [1 – exp(?0.268 × (t + 1.753)] and the growth performance index (Φ′) was 6.056.  相似文献   
872.
The objective of the study was to determine the features of the bottom trawl fishery such as catch composition, catch per unit effort (CPUE) and the discard ratios in the S??ac?k Bay fishery, central Aegean Sea. A commercial trawler conducted trawl operations from October 2008 to April 2009, with a total of 18 trawls in autumn, winter and spring (six hauls per season). In total, 84 species were identified, 47 of which belonged to the bony fishes, while other groups contributed nine (cartilaginous fish), 10 (cephalopods), 13 (crustaceans), four (echinoderms) and one (porifera) species. Some 49 species were discarded regardless of length. Total catch was 3693.2 kg of which 66.8% was marketed. Among the commercial species, rose shrimp (Parapenaeus longirostris) dominated the catch composition with 998 kg. However, discards accounted for 33.2% of the total catch biomass, with the majority represented by Lampanyctus crocodilus with 97 kg total weight. The study area is considered one of the most efficient trawling zones in the Aegean Sea and thus requires long‐term monitoring in terms of fish stocks and trawl discards for the preparation of well‐informed decisions for a sustainable fishery.  相似文献   
873.
Fishing gear losses remain a serious problem for marine life; these losses are also the source of an invisible fishing mortality. This study is an analysis of this problem within the artisanal fisheries of Istanbul. From September 2009 through May 2010, face‐to‐face interviews were conducted in 27 fishing ports for a total of 282 questionnaires. Estimates of lost fishing gear were 229.48 km of set nets, 2700 m of longlines, and 14 fish traps. Turbot nets had the highest loss ratio (54.73%), followed by bonito nets (16%), red mullet nets (7.36%), and encircling trammel nets (4.83%). The four major causes of net loss were: conflicts with other gear types (trawl and purse seine), conflicts with cargo vessels, bottom structure hindrances, and bad weather conditions. Bottom structures were the single factor in net losses for longlines and fish traps. The study observed that large quantities of nets had been lost, and that each net type showed a positive relationship between the number of nets used and the number of nets lost. Separate zones for artisanal and industrial fisheries are recommended as a realistic approach to reduce the losses of fishing gear and the impact of ‘ghost fishing’.  相似文献   
874.
Glucocorticoids (GC) often are administered during pregnancy, but despite their widespread use in clinical practice, it remains uncertain how GC exposure affects pro-angiogenic factors and their receptors. We investigated the effects of GC on vascular endothelial growth factor (VEGF), placental growth factor (PIGF), vascular endothelial growth factor receptor 1 (VEGFR1) and vascular endothelial growth factor receptor 2 (VEGFR2) protein and mRNA expressions and investigated the possible association of GC with the Akt/mTOR pathway. We incubated human umbilical vein endothelial cells (HUVECs) with a synthetic GC, triamcinolone acetonide (TA). TA administration caused decreased cellular and soluble VEGF and VEGFR1 protein expressions and increased soluble VEGFR2 expression. VEGF, VEGFR1 and VEGFR2 mRNA expressions were altered in a time and dose dependent manner. PIGF protein expression was unaffected by TA treatment, but PIGF mRNA expression decreased in a dose dependent manner after incubation for 48 and 72 h. Phospho-mTOR and phospho-Akt expressions were unaffected. Phospho-p70S6K and phospho-4EBP1 protein expressions and the vascular network forming capacity of HUVECs decreased in a dose dependent manner. We found that GC exert detrimental effects on angiogenesis by altering cellular and soluble angiogenic protein and mRNA levels, and vascular network forming capacities by the Akt/mTOR pathway.  相似文献   
875.
876.
Neurological diseases such as Alzheimer’s and Parkinson’s diseases are incurable progressive neurological disorders caused by the degeneration of neuronal cells and characterized by motor and non-motor symptoms. Curcumin, a turmeric product, is an anti-inflammatory agent and an effective reactive oxygen and nitrogen species scavenging molecule. Hydrogen peroxide (H2O2) is the main source of oxidative stress, which is claimed to be the major source of neurological disorders. Hence, in this study we aimed to investigate the effect of curcumin on Ca2+ signaling, oxidative stress parameters, mitochondrial depolarization levels and caspase-3 and -9 activities that are induced by the H2O2 model of oxidative stress in SH-SY5Y neuronal cells. SH-SY5Y neuronal cells were divided into four groups namely, the control, curcumin, H2O2, and curcumin?+?H2O2 groups. The dose and duration of curcumin and H2O2 were determined from published data. The cells in the curcumin, H2O2, and curcumin?+?H2O2 groups were incubated for 24?h with 5?µM curcumin and 100?µM H2O2. Lipid peroxidation and cytosolic free Ca2+ concentrations were higher in the H2O2 group than in the control group; however, their levels were lower in the curcumin and curcumin?+?H2O2 groups than in the H2O2 group alone. Reduced glutathione (GSH) and glutathione peroxidase (GSH-Px) values were lower in the H2O2 group although they were higher in the curcumin and curcumin?+?H2O2 groups than in the H2O2 group. Caspase-3 activity was lower in the curcumin group than in the H2O2 group. In conclusion, curcumin strongly induced modulator effects on oxidative stress, intracellular Ca2+ levels, and the caspase-3 and -9 values in an experimental oxidative stress model in SH-SY5Y cells.  相似文献   
877.
878.
Home health care is one of the recent service systems where human resource planning has a great importance. The assignment of patients to care givers is a relevant issue that the home health care service provider must address before generating the daily routes. The assignment decision is typically made without knowing the visiting sequence, which creates some uncertainties and disparities regarding the effective workload of care givers. However, taking into account travel times in the care giver workload while solving the assignment problem is not straightforward, because travel times can also be affected by clinical conditions of patients and their homes. Providing good travel time estimates that would be used in the assignment decision is the specific topic this paper focuses on. In particular, we propose a data-driven method to estimate the travel times of care givers in the assignment problem when their routes are not available yet. The method, based on the Kernel regression technique, uses the travel times observed from previous periods to estimate the time necessary for visiting a set of patients located in specific geographical locations. The main advantage offered by this technique is the empirical modelling of the travel routes generated by care givers. Numerical results based on realistic problem instances indicate that the proposed estimation method performs better than the average value and k-nearest neighbor search methods and can be successfully used in a two-stage approach that first assigns patients to care givers and then defines their routes.  相似文献   
879.
880.
Background: Global climate change has the potential to shape evolutionary trajectories of invasive species via many routes, including through changes in mating systems. Many cleistogamous (CL) plants adjust investment in CL (selfed) vs. chasmogamous (CH, potentially outcrossed) progeny across environmental gradients. However, the details of such adjustments are lacking for highly invasive plant species.

Aims: We used a highly invasive grass, Microstegium vimineum, as a model for understanding how changes in water-induced stress (including potential associated changes in soil nutrient availability) might affect mating systems and thus evolutionary change in invasive species. We predicted that plants would respond to increased water-induced stress through a relative reduction in investment in CL vs. CH reproduction (i.e., a decrease in the CL:CH ratio).

Methods: Under greenhouse conditions, we measured fecundity (number of inflorescences and florets per plant) as well as relative investment in CL vs. CH florets (CL:CH ratios for number of inflorescences, florets per inflorescence, overall florets) in response to three watering treatments approximating mesic (low) to inundated (high) conditions.

Results: Plant biomass was significantly lower in high-watering treatment relative to intermediate and low treatments, indicating that the high-water condition was stressful. Contrary to expectations, stressed plants significantly increased relative investment in CL reproduction, a pattern associated with decreased inflorescence number and increased numbers of CL florets per inflorescence.

Conclusions: We conclude that changes in water-induced stress could strongly influence realised rates of outcrossing in this invasive plant, leading to mating system evolution, and altered invasiveness.  相似文献   

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