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101.
102.
Four unusual pregnane derivatives, 5alpha-pregna-1,20-dien-3-one (1), 1,4,20-pregnatrien-3-one (3), 5alpha-pregn-20-en-3alpha-o1 o-acetate (4), and 5alpha-pregn-20-en-1alpha,3alpha-diol 3-acetate (6) have been isolated from an unidentified soft coral from Canton Island. 相似文献
103.
Seahorses, pipefish and their syngnathiform relatives are considered unique amongst fishes in using elastic recoil of post-cranial tendons to pivot the head extremely quickly towards small crustacean prey. It is known that pipefish activate the epaxial muscles for a considerable time before striking, at which rotations of the head and the hyoid are temporarily prevented to allow energy storage in the epaxial tendons. Here, we studied the motor control of this system in seahorses using electromyographic recordings of the epaxial muscles and the sternohyoideus-hypaxial muscles with simultaneous high-speed video recordings of prey capture. In addition we present the results from a stimulation experiment including the muscle hypothesised to be responsible for the locking and triggering of pivot feeding in seahorses (m. adductor arcus palatini). Our data confirmed that the epaxial pre-activation pattern observed previously for pipefish also occurs in seahorses. Similar to the epaxials, the sternohyoideus-hypaxial muscle complex shows prolonged anticipatory activity. Although a considerable variation in displacements of the mouth via head rotation could be observed, it could not be demonstrated that seahorses have control over strike distance. In addition, we could not identify the source of the kinematic variability in the activation patterns of the associated muscles. Finally, the stimulation experiment supported the previously hypothesized role of the m. adductor arcus palatini as the trigger in this elastic recoil system. Our results show that pre-stressing of both the head elevators and the hyoid retractors is taking place. As pre-activation of the main muscles involved in pivot feeding has now been demonstrated for both seahorses and pipefish, this is probably a generalized trait of Syngnathidae. 相似文献
104.
Preadult rearing conditions affected the behavior of dicofol-resistant two-spotted spider mites (Tetranychus urticae). Resistant spider mites reared on dicofol-treated leaves initiated a significantly greater number of feeding bouts on dicofol-treated leaves than did genetically identical spider mites reared on residue-free leaves. Therefore the prior exposure of resistant spider mites resulted in induced feeding preferences that could exacerbate the potential outcome of the resistance by resulting in greater amounts of feeding by resistant individuals on dicofol-treated areas. Since resistant individuals that had not experienced dicofol in their lifetime did not display this feeding preference, avoidance of this phenomenon of induced feeding preference may be an undescribed value of rotations of pesticides. 相似文献
105.
Summary The cloning of glucoamylase geneSTA using theSUC2 promoter intoSaccharomyces cerevisiae was performed. The signal sequence ofSTA gene was used for the secretion of glucoamylase protein. The plasmid constructed in this way was named YEpSUCSTA and its expression was identified. The expression of YEpSUCSTA was repressed in the presence of glucose in growth medium, but derepressed when glucose became depleted. YEpSUCSTA showed the similar efficiency of glucoamylase secretion as YEpSTA-F which has the entireSTA gene. Glucoamylase activity in starch-glucose medium was largely increased because cell mass and plasmid stability were high in biosynthesis phase compared to extracellular glucoamylase activities in media which starch or glucose was the only carbon source. 相似文献
106.
107.
Understory vegetation as an indicator for floodplain forest restoration in the Mississippi River Alluvial Valley,U.S.A. 下载免费PDF全文
Diane De Steven Stephen P. Faulkner Bobby D. Keeland Michael J. Baldwin John W. McCoy Steven C. Hughes 《Restoration Ecology》2015,23(4):402-412
In the Mississippi River Alluvial Valley (MAV), complete alteration of river‐floodplain hydrology allowed for widespread conversion of forested bottomlands to intensive agriculture, resulting in nearly 80% forest loss. Governmental programs have attempted to restore forest habitat and functions within this altered landscape by the methods of tree planting (afforestation) and local hydrologic enhancement on reclaimed croplands. Early assessments identified factors that influenced whether planting plus tree colonization could establish an overstory community similar to natural bottomland forests. The extent to which afforested sites develop typical understory vegetation has not been evaluated, yet understory composition may be indicative of restored site conditions. As part of a broad study quantifying the ecosystem services gained from restoration efforts, understory vegetation was compared between 37 afforested sites and 26 mature forest sites. Differences in vegetation attributes for species growth forms, wetland indicator classes, and native status were tested with univariate analyses; floristic composition data were analyzed by multivariate techniques. Understory vegetation of restoration sites was generally hydrophytic, but species composition differed from that of mature bottomland forest because of young successional age and differing responses of plant growth forms. Attribute and floristic variation among restoration sites was related to variation in canopy development and local wetness conditions, which in turn reflected both intrinsic site features and outcomes of restoration practices. Thus, understory vegetation is a useful indicator of functional progress in floodplain forest restoration. 相似文献
108.
Priority threat management of invasive animals to protect biodiversity under climate change 下载免费PDF全文
Jennifer Firn Ramona Maggini Iadine Chadès Sam Nicol Belinda Walters Andy Reeson Tara G. Martin Hugh P. Possingham Jean‐Baptiste Pichancourt Rocio Ponce‐Reyes Josie Carwardine 《Global Change Biology》2015,21(11):3917-3930
Climate change is a major threat to global biodiversity, and its impacts can act synergistically to heighten the severity of other threats. Most research on projecting species range shifts under climate change has not been translated to informing priority management strategies on the ground. We develop a prioritization framework to assess strategies for managing threats to biodiversity under climate change and apply it to the management of invasive animal species across one‐sixth of the Australian continent, the Lake Eyre Basin. We collected information from key stakeholders and experts on the impacts of invasive animals on 148 of the region's most threatened species and 11 potential strategies. Assisted by models of current distributions of threatened species and their projected distributions, experts estimated the cost, feasibility, and potential benefits of each strategy for improving the persistence of threatened species with and without climate change. We discover that the relative cost‐effectiveness of invasive animal control strategies is robust to climate change, with the management of feral pigs being the highest priority for conserving threatened species overall. Complementary sets of strategies to protect as many threatened species as possible under limited budgets change when climate change is considered, with additional strategies required to avoid impending extinctions from the region. Overall, we find that the ranking of strategies by cost‐effectiveness was relatively unaffected by including climate change into decision‐making, even though the benefits of the strategies were lower. Future climate conditions and impacts on range shifts become most important to consider when designing comprehensive management plans for the control of invasive animals under limited budgets to maximize the number of threatened species that can be protected. 相似文献
109.
Jong Shin Woo Seung Joon Hwang Hyun Soo Kim Jin Bae Kim Woo-Shik Kim Kwon Sam Kim Myung Ho Jeong Weon Kim Korea Acute Myocardial Infarction Registry Investigators 《PloS one》2015,10(12)
Objective
Large randomized trials have failed to show a beneficial effect of statin treatment in chronic HF. The investigators tried to evaluate the long-term effects of statin therapy in patients with new onset heart failure (HF) following acute myocardial infarction (AMI).Methods
Between January 2008 and December 2011, a total of 13,616 AMI patients were enrolled in the Korea Acute Myocardial Infarction Registry (KAMIR) which was a prospective, multi-center, nationwide, web-based database of AMI in Korea. From this database, we studied 1,055 patients with AMI who had newly developed severe acute HF [left ventricular ejection fraction ≤ 40%] and were discharged alive. The patients were divided into two groups, a statin group (n = 756) and a no-statin group (n = 299). We investigated the one-year major adverse cardiovascular events (MACEs), including all-cause mortality, MI, and any revascularization of each group. We then performed a propensity-score matched analysis.Results
In the original cohort, one-year MACEs were similar between the two groups (16.5% vs. 14.7% in the statin or no-statin groups; p = 0.47). Propensity-score matching yielded 256 pairs, and in that population we observed comparable results in terms of MACEs (18.0% vs. 12.5% in the statin or no-statin groups, p = 0.11) and mortality (5.1% vs. 3.5% in the statin or no-statin groups, p = 0.51). Cox-regression analysis revealed that statin therapy was not an independent predictor for occurrence of a MACE [Hazard ratio (HR) 1.11, 95% CI 0.79–1.57, p = 0.54] or all-cause mortality (HR 1.42, 95% CI 0.75–2.70, p = 0.28).Conclusion
Statin therapy was not associated with a reduction in the long-term occurrence of MACEs or mortality in survivors of AMI with severe acute HF in this retrospective cohort study. 相似文献110.
Benjamin T. Dunkley Paul A. Sedge Sam M. Doesburg Richard J. Grodecki Rakesh Jetly Pang N. Shek Margot J. Taylor Elizabeth W. Pang 《PloS one》2015,10(4)
Post-traumatic stress disorder (PTSD) is a mental health injury characterised by re-experiencing, avoidance, numbing and hyperarousal. Whilst the aetiology of the disorder is relatively well understood, there is debate about the prevalence of cognitive sequelae that manifest in PTSD. In particular, there are conflicting reports about deficits in executive function and mental flexibility. Even less is known about the neural changes that underlie such deficits. Here, we used magnetoencephalography to study differences in functional connectivity during a mental flexibility task in combat-related PTSD (all males, mean age = 37.4, n = 18) versus a military control (all males, mean age = 33.05, n = 19) group. We observed large-scale increases in theta connectivity in the PTSD group compared to controls. The PTSD group performance was compromised in the more attentionally-demanding task and this was characterised by ''late-stage'' theta hyperconnectivity, concentrated in network connections involving right parietal cortex. Furthermore, we observed significant correlations with the connectivity strength in this region with a number of cognitive-behavioural outcomes, including measures of attention, depression and anxiety. These findings suggest atypical coordination of neural synchronisation in large scale networks contributes to deficits in mental flexibility for PTSD populations in timed, attentionally-demanding tasks, and this propensity toward network hyperconnectivity may play a more general role in the cognitive sequelae evident in this disorder. 相似文献