200,161 research outputs found

    Feather growth rate and mass in nearctic passerines with variablemigratory behavior and molt pattern

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    Bird species vary greatly in the duration of their annual complete feather molt. However, such variation is not well documented in birds from many biogeographic areas, which restricts our understanding of the diversification of molt strategies. Recent research has revealed that molt duration can be estimated in passerines from ptilochronology-based measurements of the growth rate of their tail feathers. We used this approach to explore how molt duration varied in 98 Nearctic species that have different migratory strategies and molt patterns. As previously documented for Palearctic species, migration was associated with a shortening of molt duration among species that molted during summer on their breeding range. However, molts of winter-molting migratory species were as long as those of summer-molting sedentary species, which suggests that winter molt also allows Nearctic migrants to avoid the temporal constraints experienced during summer. Our results also suggest that migratory species that undergo a stopover molt within the Mexican monsoon region have the shortest molt duration among all Nearctic passerines. Interestingly, and contrary to expectations from a potential tradeoff between molt duration and feather quality, observed variation in feather growth rate was positively correlated with differences in tail feather mass, which may be caused by differences among groups in the availability of resources for molting. We encourage the use of similar approaches to study the variation in molt duration in other geographic areas where knowledge of the evolution of molt is limited.

    Effects of age, density, and seasonality on molt pattern in the mammal genus (Peromyscus)

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    Molting, or replacement of pelage (hair) in mammals, occurs during ontogeny as individuals transition from juveniles to adults. Environmental factors can cause variation in molt in many species for thermoregulatory and camouflage purposes. Within and among years molt can vary by time and age or by reproductive status. Past studies have found differences in molt pattern and timing depending upon age, and between captive reared and wild caught individuals. There has been little investigation into the molting characteristics of Peromyscus leucopus and P. maniculatus, specifically in comparison to adults and juveniles. I used molt observed from museum specimens collected at Bartlett Experimental Forest over a three-year period to determine if there are evident molt patterns in both Peromyscus spp. Specifically, I looked for differences in percent molt and number of individuals molting as a result of seasonality and age. Molts were digitized in Photoshop and pattern and symmetry were analyzed in ImageJ. In both species, individuals show a seasonal trend in molt timing and symmetry. This may reflect differences in resource availability and energy expenditure among years

    OSMOTIC RESPONSES OF SEGARA ANAKAN FINE SHRIMP (Metapenaeus elegans) ADULTS IN VARIOUS SALINITY AND MOLTING STAGES

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    A research on eco-physiological characteristics of fine shrimp (Metapenaeus elegans) with special emphasis on the osmotic responses and isosmotic medium requirement for adult spawners in various molting stages was conducted. Adult stocks of M. elegans origin from the Segara Anakan lagunas of the South West of Central Java region were collected and used as experimental shrimps. The shrimps were hold in three 500 l-acclimation tanks and treated according to Anggoro and Nakamura’s method. The seawater salinity level in the tank 1, 2, and 3 was 25, 28, and 22 ppt, respectively. Osmotic response of the shrimps was examined during 3 molting stages, i.e. pre-molt/ post-molt, molt, and inter-molt phases by using an automatic microosmometer Roebling. The results showed that osmotic responses were closely related to the salinity of water medium and molting stages. It was also found that the minimum osmotic works of fine shrimp occurred in isosmotic medium, i.e. 16 to 20 ppt for post-molt, 28 to 30 ppt for molt, and 22 to 25 ppt for inter-molt stages. It was concluded that the range of isosmotic media for the adult of fine shrimp was 22 to 28 ppt or equals to 642.06 to 817.31 mOsm/l H2O

    Cytotoxicity of the Bacillus thuringiensis Crystal Protein against Mammalian Cells

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    The crystal proteins produced by Bacillus thuringiensis subsp, israelensis (Bti) and subsp. coreanensis A1519 strain were examined for the cytotoxicity against MOLT-4 and HeLa cells by MTT assay and LDH assay, The A1519 crystal proteins processed by proteinase K exhibited the specific cell-killing activity toward MOLT-4 with little damage to the cell membrane, On the other hand, the Bti crystal proteins processed by proteinase K caused the substantial damage to the cell membrane of both MOLT-4 and HeLa, leading to the cell lysis. The non-digested crystal proteins of both strains exhibited no cytotoxicity, These data suggested that while the Bti crystal proteins caused the colloid-osmotic swelling and cell lysis of MOLT-4 and HeLa, the proteinase K-digested A1519 crystal proteins induced the specific cell death of MOLT-4 through a mechanism other than that of Bti

    2-year follow-up report on micromotion of a short tibia stem.

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    Background and purpose - A shortened tibial stem could influence the early prosthetic fixation. We therefore compared the short stem to the standard-length stem using radiostereometric analysis (RSA) as primary outcome measure. Patients and methods - 60 patients were randomized to receive a cemented Triathlon total knee arthroplasty (TKA) with a tibial tray of either standard or short stem length. The patients were blinded regarding treatment allocation. The micromotion of the tibial component was measured by RSA postoperatively, at 3 months, and after 1 and 2 years; clinical outcome was measured with the American Knee Society score (AKSS) and the knee osteoarthritis and injury outcome score (KOOS). Results - The maximum total point motion (MTPM) for the standard stem was 0.36 (SD 0.16) mm at 3 months, 0.51 (SD 0.27) mm at 1 year, and 0.54 (SD 0.28) mm at 2 years. For the short stem, it was 0.42 (0.24) mm, 0.59 (0.43) mm, and 0.61 (0.39) mm. 4 short-stemmed components and 2 standard-stemmed components had more than 0.2 mm of migration between the first- and second-year follow-up, and were classified as continuously migrating. Interpretation - The short-stemmed cemented tibial prosthesis showed an early prosthetic migratory pattern similar to that of the standard-stemmed cemented Triathlon knee prosthesis. The number of continuously migrating tibial plates in each group is predictive of a lower revision rate than 5% at 10 years

    Starre biomimetische Adrenalinrezeptor-Modelle

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    Im Rahmen dieser Arbeit wurden starre biomimetische Rezeptoren auf Bisphosphonat-Basis für Catecholamine, die eine wichtige Klasse von Hormonen und Neurotransmittern darstellen, entwickelt und synthetisiert. Diese makrozyklischen oder pinzettenförmigen Wirtverbindungen wurden durch 1H-NMR-Titrationen auf ihre Bindungseigenschaften in polarer Lösung untersucht. Desweiteren wurden die amphiphilen Rezeptoren in eine Lipidmonoschicht an der Luft/Wasser-Grenzschicht eingelagert und zeigten auch in diesem einfachen Membranmodell starke und selektive Bindung von Adrenalinderivaten

    Molt 1999

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    Methods for quantifying molt in adult and juvenile Dark-eyed Juncos (Junco hyemalis) at Mountain Lake Biological Station, Pembroke, Virginia

    Estimated N leaching losses for organic and conventional farming in Denmark

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    The impact of organic compared to conventional farming practices on N leaching loss was studied for Danish mixed dairy and arable farms using an N balance approach based on representative data. On mixed dairy farms a simple N balance method was used to estimate N surplus and N leaching loss. On arable farms the simple N balance method was unreliable due to changes in the soil N pool. Consequently, the FASSET simulation model was used to estimate N surplus, N leaching loss and the changes in the soil N pool. The study found a lower N leaching loss from organic than conventional mixed dairy farms, primarily due to lower N inputs. On organic arable farms the soil N pool was increasing over years but the N leaching loss was comparable to conventional arable farms. The soil N pool was primarily increased by organic farming practices and incorporation of straw. The highest increase in the soil N pool was seen on soils with a low level of soil organic matter. The level of N leaching loss was dependent on soil type, the use of catch crops and the level of soil organic matter, whereas incorporation of straw had a minor effect. N leaching was highest on sandy soils with a high level of soil organic matter and no catch crops. The study stresses the importance of using representative data of organic and conventional farming practices in comparative studies of N leaching loss

    Records molt preuats

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    Impact of organic pig production systems on CO2 emission, C sequestration and nitrate pollution

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    Organic rules for grazing and access to outdoor area in pig production may be met in different ways, which express compromises between considerations for animal welfare, feed self-reliance and negative environmental impact such as greeehouse gas emissions and nitrate pollution. This article compares environmental impact of the main organic pig systems in Denmark. Normally sows are kept in huts on grassland and finishing pigs are being raised in stables with access to an outdoor run. One alternative practised is rearing also the fattening pigs on grassland all year round. The third method investigated was a one-unit pen system mainly consisting of a deep litter area under a climate tent and with restricted access to a grazing area. Using life cycle assessment (LCA) methodology, the emissions of greenhouse gasses of the all free range system was estimated to be 3.3 kg CO2-equivalents kg-1 liveweight pig, which was significantly higher than the indoor fattening system and the tent system yeilding 2.9 and 2.8 kg CO2-eq. kg-1 pig respectively. This was 7-22% higher compared with Danish conventional pig production but, due to the integration of grass-clover in the organic crop rotations these had an estimated net soil carbon sequestration. When carbon sequestration was included in the LCA then the organic systems had lower green house gas emissions compared with the conventional pig production. Eutrophication in nitrate equivalents per kg pig was 21-65% higher in the organic pig systems and acidification was 35-45% higher per kg organic pig compared with the conventional system. We conclude that even though the all free range system theoretically has agro-ecological advantages over the indoor fattening system and the tent system due to a larger grass-clover area this potential is difficult to implement in practice due to problems with leaching on sandy soil. Only if forage can contribute a larger proportion of the pigfeed-uptake may the free range system be economically and environmentally competitive. Improvement of nitrogen cycling and efficiency is the most important factor for reducing the overall environmental load from organic pig meat. Presently a system with pig fattening in stables and concrete covered outdoor runs seems to be the best solution from an environmental point of view
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