872 resultados para Two-body abrasion
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Mutations in 12 genes regulating Drosophila melanogaster mushroom body (MB) development were each studied in two genetic backgrounds. In all cases, brain structure was qualitatively or quantitatively different after replacement of the "original" genetic background with that of the Canton Special wild-type strain. The mushroom body miniature gene (mbm) was investigated in detail. mbm supports the maintenance of MB Kenyon cell fibers in third instar larvae and their regrowth during metamorphosis. Adult mbm1 mutant females are lacking many or most Kenyon cell fibers and are impaired in MB-mediated associative odor learning. We show here that structural defects in mbm1 are apparent only in combination with an X-linked, dosage-dependent modifier (or modifiers). In the Canton Special genetic background, the mbm1 anatomical phenotype is suppressed, and MBs develop to a normal size. However, the olfactory learning phenotype is not fully restored, suggesting that submicroscopic defects persist in the MBs. Mutant mbm1 flies with full-sized MBs have normal retention but show a specific acquisition deficit that cannot be attributed to reductions in odor avoidance, shock reactivity, or locomotor behavior. We propose that polymorphic gene interactions (in addition to ontogenetic factors) determine MB size and, concomitantly, the ability to recognize and learn odors.
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Hormonal and genetic factors strongly influence the susceptibility of inbred mice to hepatocarcinogenesis. Female C57BR/cdJ (BR) mice are extremely susceptible to liver tumor induction relative to other strains because they are genetically insensitive to the inhibition of hepatocarcinogenesis by ovarian hormones. To determine the genetic basis for the sensitivity of BR mice relative to resistant C57BL/6J (B6) mice, we treated 12-day-old B6BRF1 x B6 and B6BRF1 x B6BRF1 (F2) animals with N,N-diethylnitrosamine (0.1 micromol/g of body weight) and enumerated liver tumors at 32 weeks of age in males and at 50 weeks in females. Genomic DNA samples from backcross and F2 mice were analyzed for 70 informative simple sequence length polymorphism markers. Genetic markers on chromosome 17 (D17Mit21) and chromosome 1 (D1Mit33) cosegregated with high tumor multiplicity in both sexes. Together, these loci [designated Hcf1 and Hcf2 (Hepatocarcinogenesis in females), respectively] account for virtually all of the difference in sensitivity between BR and B6 mice. The Hcf1 locus accounts for a majority of the higher susceptibility of BR mice of both sexes. Backcross female mice heterozygous at both loci (33 +/- 23 tumors per mouse) and at Hcf1 only (17 +/- 18) were 15- and 8-fold more sensitive, respectively, than mice homozygous for the B6 alleles at Hcf1 and Hcf2 (2.2 +/- 3.9). In backcross male mice, the double heterozygotes (35 +/- 22) and Hcf1 heterozygotes (28 +/- 12) were 5.4- and 4.3-fold more sensitive than mice homozygous for B6 alleles at both loci (6.5 +/- 5.4).
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The primary aim of this study was to examine the effects of 6-week strength training with whole body vibration (WBV) on leg strength and jumping performance in volleyball and beach volleyball players. Twenty-three sub-elite male volleyball (VB; n=12) and beach volleyball players (BVB; n=11) aged 21.2±3.0 years were divided into two groups and subjected to 6 weeks of strength training (three one-hour sessions per week): (I) 12 players (6 VB and 6 BVB players) underwent training with WBV (30-40 Hz, 1.7-2.5 mm, 3.0-5.7 g), and (II) 11 players (6 VB and 5 BVB players) underwent traditional strength training. Squat jump (SJ) and countermovement squat jump (CMJ) measurements by the Ergo Tester contact platform and maximum leg press test (1RM) were conducted. Three-factor (2 time x 2 WBV use x 2 discipline) analysis of variance for SJ, CMJ and 1RM revealed a significant time main effect (p<0.001), a WBV use effect (p<0.001) and a discipline effect (p<0.001). Significantly greater improvements in the SJ (p<0.001) and CMJ (p<0.001) and in 1RM (p<0.001) were found in the WBV training groups than in traditional training groups. Significant 3-way interaction effects (training, WBV use, discipline kind) were also found for SJ, CMJ and 1RM (p=0.001, p<0.001, p=0.001, respectively). It can be concluded that implementation of 6-week WBV training in routine practice in volleyball and beach volleyball players increases leg strength more and leads to greater improvement in jump performance than traditional strength training, but greater improvements can be expected in beach volleyball players than in volleyball players.
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BAPNE Method is a method based on cognitive stimulation integrating music and movement through body percussion. The aim of this research is to explore its whole potential as a tool to build teams. Team building is a philosophy for work design, and since over two decades ago, it defends that obtaining a high performance and organizing efficiency is more useful to perceive employees as interdependent members in a team of work than individuals ones. From this viewpoint, this research advocates that BAPNE Method’s body percussion practice will have an impact on this vision of team work directly. For its own characteristics, body percussion stimulates ways of contact in movement, which ease social ties and, especially, promote group cohesion. Through social, body and, affective dimension; BAPNE Method is capable of developing a shared vision and a single aim, to stimulate team work identity and an atmosphere of trust; and finally, to improve individual communication and satisfaction levels in group tasks.
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While part of a single country, the Indonesian archipelago covers several biogeographic regions, and the high levels of national shipping likely facilitate transfer of non-native organisms between the different regions. Two vessels of a domestic shipping line appear to have served as a transport vector for the Asian green mussel Perna viridis (Linnaeus, 1758) between regions. This species is indigenous in the western but not in the eastern part of the archipelago, separated historically by the Sunda Shelf. The green mussels collected from the hulls of the ferries when in eastern Indonesia showed a significantly lower body condition index than similar-sized individuals from three different western-Indonesian mussel populations. This was presumably due to reduced food supply during the ships' voyages. Although this transportinduced food shortage may initially limit the invasive potential (through reduced reproductive rates) of the translocated individuals, the risk that the species will extend its distributional range further into eastern Indonesia is high. If the species becomes widely established in eastern Indonesia, there will then be an increased risk of incursions to Australia, where the mussel is listed as a high-priority pest species.
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Marine invertebrates with open circulatory system establish low and constant oxygen partial pressure (Po2) around their tissues. We hypothesized that as a first step towards maintenance of low haemolymph and tissue oxygenation, the Po2 in molluscan mantle cavity water should be lowered against normoxic (21 kPa) seawater Po2, but balanced high enough to meet the energetic requirements in a given species. We recorded Po2 in mantle cavity water of five molluscan species with different lifestyles, two pectinids (Aequipecten opercularis, Pecten maximus), two mud clams (Arctica islandica, Mya arenaria), and a limpet (Patella vulgata). All species maintain mantle cavity water oxygenation below normoxic Po2. Average mantle cavity water Po2 correlates positively with standard metabolic rate (SMR): highest in scallops and lowest in mud clams. Scallops show typical Po2 frequency distribution, with peaks between 3 and 10 kPa, whereas mud clams and limpets maintain mantle water Po2 mostly <5 kPa. Only A. islandica and P. vulgata display distinguishable temporal patterns in Po2 time series. Adjustment of mantle cavity Po2 to lower than ambient levels through controlled pumping prevents high oxygen gradients between bivalve tissues and surrounding fluid, limiting oxygen flux across the body surface. The patterns of Po2 in mantle cavity water correspond to molluscan ecotypes.
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Nongenetic inheritance mechanisms such as transgenerational plasticity (TGP) can buffer populations against rapid environmental change such as ocean warming. Yet, little is known about how long these effects persist and whether they are cumulative over generations. Here, we tested for adaptive TGP in response to simulated ocean warming across parental and grandparental generations of marine sticklebacks. Grandparents were acclimated for two months during reproductive conditioning, whereas parents experienced developmental acclimation, allowing us to compare the fitness consequences of short-term vs. prolonged exposure to elevated temperature across multiple generations. We found that reproductive output of F1 adults was primarily determined by maternal developmental temperature, but carry-over effects from grandparental acclimation environments resulted in cumulative negative effects of elevated temperature on hatching success. In very early stages of growth, F2 offspring reached larger sizes in their respective paternal and grandparental environment down the paternal line, suggesting that other factors than just the paternal genome may be transferred between generations. In later growth stages, maternal and maternal granddam environments strongly influenced offspring body size, but in opposing directions, indicating that the mechanism(s) underlying the transfer of environmental information may have differed between acute and developmental acclimation experienced by the two generations. Taken together, our results suggest that the fitness consequences of parental and grandparental TGP are highly context dependent, but will play an important role in mediating some of the impacts of rapid climate change in this system.
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Pages [19]-36 contain: "The Great Law, or, The body of laws of ye province of Pennsylvania and territorys thereunto belonging, past at an assembly at Chester, als. Upland, the seventh day of ye tenth month, December, 1682." Corrections in capitalization have been made in a contemporary hand.
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The efficiency of physical separation of inclusion bodies from cell debris is related to cell debris size and inclusion body release and both factors should be taken into account when designing a process. In this work, cell disruption by enzymatic treatment with lysozyme and cellulase, by homogenization, and by homogenization with ammonia pretreatment is discussed. These disruption methods are compared on the basis of inclusion body release, operating costs, and cell debris particle size. The latter was measured with cumulative sedimentation analysis in combination with membrane-associated protein quantification by SDS-PAGE and a spectrophotometric pepticloglycan quantification method. Comparison of the results obtained with these two cell debris quantification methods shows that enzymatic treatment yields cell debris particles with varying chemical composition, while this is not the case with the other disruption methods that were investigated. Furthermore, the experiments show that ammonia pretreatment with homogenization increases inclusion body release compared to homogenization without pretreatment and that this pretreatment may be used to control the cell debris size to some extent. The enzymatic disruption process gives a higher product release than homogenization with or without ammonia pretreatment at lower operating costs, but it also yields a much smaller cell debris size than the other disruption process. This is unfavorable for centrifugal inclusion body purification in this case, where cell debris is the component going to the sediment and the inclusion body is the floating component. Nevertheless, calculations show that centrifugal separation of inclusion bodies from the enzymatically treated cells gives a high inclusion body yield and purity. (C) 2004 Wiley Periodicals, Inc.
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Factors influencing the rate of cannibalism in juvenile blue-swimmer crabs Portunus pelagicus were investigated under controlled conditions using time-lapse video recordings. This study was undertaken to improve blue-swimmer crab culture and experimentally addressed (1) prey vulnerability (2) cannibal-victim interactions, and (3) activity patterns of juveniles in varying degrees of refuge. Crabs used in the study were aged 15 weeks and sorted into two size classes; small (less than or equal to 60 mm carapace width (CW)) and large (greater than or equal to65 mm CW) of a similar sex ratio. Vulnerability and thus survival was influenced by body size variation, moult stage and refuge availability. Crabs with carapace width less than or equal to 60 mm were more vulnerable than larger individuals, as indicated by significant differences in survival rates. As predicted, juveniles in transition stages associated with ecdysis were especially vulnerable. Premoult (redliner) crabs appeared to be in a high state of agitation as evidenced by the frequency of agonistic encounters and this may be a contributing factor to the high mortality observed at this critical premoult stag. increases in refuge density increased survival of juveniles proportionally, indicating that the quantity of shelter is important for reducing cannibalism in this species. Cannibal-victim interactions were frequently asymmetrical in terms of size and moult stage. Cannibals were significantly heavier than victims, and were predominantly at intermoult stage. Sexual biases among cannibals and victims were not found in this study. Activity patterns of juveniles were influenced by the experimental conditions. Crabs provided with high refuge showed reduced aggressive activity and increased time spent resting, but unchanged locomotion or feeding activity. Regular grading as well as the presence of suitable shelter for newly moulted crabs is recommended for improving culture of P. pelagicus. Research into inducing synchronous moulting may also yield promising results. (C) 2004 Elsevier B.V. All rights reserved.
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Pearsonellum pygmaeus n. sp. is described from Cromileptes altivelis (Serranidae), the Barramundi Cod, from Heron Island (southern Great Barrier Reef) and Lizard Island (northern Great Bat-Her Reef). This new species differs from Pearsonellum eorventum (type and only species) in the combination of smaller overall body size, the relative distance of the brain from the anterior end, the relative lengths of both the oesophagus and the testis, the degree to which the testis extends outside the intercaecal field, the shape of the testis, the shape and size of the ovary and the extent to which the uterzus loops around the ovary. There are in addition, 20 base pair differences between the ITS2 rDNA sequence of P. pygmaeus n. sp. and that of P corventum. Three new host records for P. corventum are reported. Adelomyllos teenae n. g., n. sp. is described from Epinephelus coioides (Serranidae), the Estuary Cod, from Moreton Bay, southeast Queensland. The new genus differs from the 22 other sanguinicolid genera in the combined possession of two testes, a cirrus-sac, separate genital pores, a post-ovarian uterus and an H-shaped intestine. A. teenae n. sp. is the third sanguinicolid described from the Epinephelinae. Sanguinicolids have now been reported from 11 species of Serranidae. (C) 2004 Elsevier Ireland Ltd. All rights reserved.
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Primary objective: The study aimed to examine the changes in water distribution in the soft tissue during systemic steroid activity. Research design: A three-way cross-over, randomized, placebo-controlled, double-blind trial was used, including 4 weeks of fluticasone propionate pMDI 200 mug b.i.d. delivered via Babyhaler(R), budesonide pressurized metered dose inhaler (pMDI) 200 mug b.i.d. delivered via Nebuchamber(R) and placebo. Spacers were primed before use. In total, 40 children aged 1-3 years, with mild intermittent asthma were included. Twenty-five of the children completed all three treatments. At the end of each treatment period body impedance and skin ultrasonography were measured. Methods and procedures: We measured changes in water content of the soft tissues by two methods. Skin ultrasonography was used to detect small changes in dermal water content, and bioelectrical impedance was used to assess body water content and distribution. Main outcomes and results: We found an increase in skin density of the shin from fluticasone as measured by ultrasonography (p = 0.01). There was a tendency for a consistent elevation of impedance parameters from active treatments compared to placebo although overall this effect was not statistically significant (0.1< p <0.2). However, sub-analyses indicated a significant effect on whole-body and leg impedance from budesonide treatment (p <0.05). Conclusion: Decreased growth during inhaled steroid treatment seems to partly reflect generalized changes in body water.
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Objective: To explore the relationship between family average income (FAI; an index of socio-economic status) and body mass index (BMI; a widely used, inexpensive indicator of weight status) above the healthy weight range in a region of Mainland China. Design: Population-based cross-sectional study, conducted between October 1999 and March 2000 on a sample of regular local residents aged 35 years or older who were selected by random cluster sampling. Setting: Forty-five administrative villages selected from three urban districts and two rural counties of Nanjing municipality, Mainland China, with a regional population of 5.6 million. Subjects: In total, 29 340 subjects participated; 67.7% from urban and 32.3% from rural areas; 49.8% male and 50.2% female. The response rate among eligible participants was 90.1%. Results: The proportion of participants classified as overweight was 30.5%, while 7.8% were identified as obese. After adjusting for possible confounding variables (age, gender, area of residence, educational level, occupational and leisure-time physical activity, daily vegetable consumption and frequency of red meat intake), urban participants were more likely to be overweight or obese relative to their rural counterparts, more women than men were obese, and participants in the lowest FAI tertile were the least likely to be above the healthy weight range. Conclusions: The proportion of adults with BMI above the healthy weight range was positively related to having a higher socio-economic status (indexed by FAI) in a regional Chinese population.
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Doped ceria (CeO2,) compounds are fluorite type oxides, which show oxide ionic conductivity higher than yttria stabilized zirconia (YSZ), in oxidizing atmospheres. As a consequence of this, considerable interest has been shown in application of these materials for 'low (500-650 degreesC)' or 'intermediate (650-800 degreesC)' temperature operation, solid oxide fuel cells (SOFCs). In this study, the authors prepared two kinds of nanosize Sm-doped CeO2 particles with different morphologies: one type was round and the other was elongated. Processing these powders with different morphology produced dense materials with very different ionic conducting properties and different nanoscale microstructures. Since both particles are very fine and well dispersed, sintered bodies with high density (relative density >95% of theoretical) could be prepared using both types of powder particles. The electrical conductivity of sintered bodies prepared from these powders with different starting morphologies was very different. Materials prepared from particles having a round shape were much higher than those produced using powders with an elongated morphology. Measured activation energies of the corresponding sintered samples showed a similar trend; round particles (60 kJ/mol), elongated particles (74 kJ/mol). While X-ray diffraction (XRD) profiles of these sintered materials were identical, diffuse scatter was observed in the back.-round of selected area electron diffraction pattern recorded from both sintered bodies. This indicated an underlying structure that appeared to have been influenced by the processing technology. Detailed observation using high-resolution transmission electron microscopy (HR-TEM) revealed that the size of microdomain with ordering of cations in the sintered body made from round shape particles was much smaller than that of the sintered body made from elongated particles. Accordingly, it is concluded that the morphology of doped CeO2 powders strongly influenced the microdomain size and electrolytic properties in the doped CeO2 sintered body. (C) 2004 Elsevier B.V. All rights reserved.