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21.
Saltwater crocodiles (Crocodylus porosus) in the Northern Territory of Australia were protected in 1971, after a severe population decline resulting from 26 yr of intense commercial hunting. By that time wild saltwater crocodiles were rarely sighted anywhere and they were commercially extinct in areas where they had once been abundant. Standardized monitoring by spotlight surveys started in 1975 and provided relative density indices over time (1975–2009) as a unique record of the post-protection recovery of a wild crocodilian population. We examined the survey data for populations at 12 major tidal rivers, individually and as a single subpopulation. The pattern of recovery in the subpopulation in both abundance and biomass was approximated by logistic curves, predicting 5.26 non-hatchling crocodiles weighing 387.64 kg sighted per kilometer of river in 2010. We predicted potential carrying capacity as 5.58 non-hatchling crocodiles (5.73% higher than 2010) weighing 519.0 kg (25.31% higher than 2010). Individual rivers showed largely different abundance and biomass among rivers. The statistical model that best described the recovery in individual rivers was not always logistic. However, where it was logistic, expected carrying capacity of different rivers showed considerable variation in abundance and biomass. The variation indicates different habitat quality among the rivers. Recovery occurred despite various consumptive uses, particularly a widespread egg-harvest program, which has been an integral part of the incentive-driven conservation program for saltwater crocodiles in the Northern Territory since 1983. We suggest that the saltwater crocodile population of the Northern Territory is achieving full recovery from uncontrolled hunting in 1945–1971. Although saltwater crocodiles are considered an important natural resource, their increase in number, size, and distribution is posing management issues for public safety. Continuation of human–crocodile conflict management through public education and strategic removal of problem crocodiles will be essential. © 2011 The Wildlife Society.  相似文献   
22.
结合田间观察和室内试验,对榆木蠹蛾HolcocerusvicariusWalker的生物学特性进行了较为系统的研究。结果表明,榆木蠹蛾在宁夏3年发生1代,幼虫主要危害枝干和根颈部,幼虫在蛀道内越冬,5月下旬老熟幼虫在被害树周围5—10cm深的沙土内分散化蛹,蛹期(21±5)d。6月初成虫开始出现,有2个羽化高峰,分别为6月中旬和7月下旬,成虫羽化当晚即可交尾,交尾当天或第2天产卵,每雌蛾产卵最多达720粒,卵期(17±5)d,孵化率为72%~88%。未交尾雌雄成虫寿命为5—6d,交尾后雌雄成虫寿命缩短为3—5d。初孵幼虫于6月中旬始见,10月下旬幼虫开始越冬。幼虫孵化后,先危害韧皮部,常10多条聚集在一起,稍大一点即蛀入木质部。本研究为制定切实可行的榆木蠹蛾有效防治提供理论依据。  相似文献   
23.
Phylogeography of five Polytrichum species within Europe   总被引:2,自引:0,他引:2  
Using allozymes and microsatellites we have analysed the genetic structure among European populations for several Polytrichum species to infer relevant factors, such as historical events or gene flow, that have shaped their genetic structure. As we observed low levels of genetic differentiation among populations, and no decreasing levels of genetic variation with increasing latitude within most of the examined species, no genetic evidence was obtained for a step-wise recolonization of Europe from southern refugia after the latest glacial period for P. commune , P. uliginosum , P. formosum and P. piliferum . The near absence of population substructuring within these species does indicate that extensive spore dispersal is the most important factor determining the genetic structure among European Polytrichum populations. Gene flow levels have apparently been sufficient to prevent genetic differentiation among populations caused by genetic drift, and to wipe out any genetic structure caused by the postglacial recolonization process. On the other hand, increased genetic differentiation of alpine P. formosum populations suggests that mountain ranges might restrict gene flow significantly among Polytrichum populations. In contrast to most examined Polytrichum species, P. juniperinum showed high levels of genetic differentiation and a profound genetic structure. Assuming that gene flow is not more restricted in P. juniperinum , these findings suggest that this species has recolonized Europe after the latest glacial period from two different refugia, one possibly being the British Isles.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society 2003, 78, 203–213.  相似文献   
24.
The laboratory mouse is the animal species of choice for most biomedical research, in both the academic sphere and the pharmaceutical industry. Mice are a manageable size and relatively easy to house. These factors, together with the availability of a wealth of spontaneous and experimentally induced mutants, make laboratory mice ideally suited to a wide variety of research areas.In cardiovascular, pharmacological and toxicological research, accurate measurement of parameters relating to the circulatory system of laboratory animals is often required. Determination of heart rate, heart rate variability, and duration of PQ and QT intervals are based on electrocardiogram (ECG) recordings. However, obtaining reliable ECG curves as well as physiological data such as core body temperature in mice can be difficult using conventional measurement techniques, which require connecting sensors and lead wires to a restrained, tethered, or even anaesthetized animal. Data obtained in this fashion must be interpreted with caution, as it is well known that restraining and anesthesia can have a major artifactual influence on physiological parameters1, 2.Radiotelemetry enables data to be collected from conscious and untethered animals. Measurements can be conducted even in freely moving animals, and without requiring the investigator to be in the proximity of the animal. Thus, known sources of artifacts are avoided, and accurate and reliable measurements are assured. This methodology also reduces interanimal variability, thus reducing the number of animals used, rendering this technology the most humane method of monitoring physiological parameters in laboratory animals3, 4. Constant advancements in data acquisition technology and implant miniaturization mean that it is now possible to record physiological parameters and locomotor activity continuously and in realtime over longer periods such as hours, days or even weeks3, 5.Here, we describe a surgical technique for implantation of a commercially available telemetry transmitter used for continuous measurements of core body temperature, locomotor activity and biopotential (i.e. onelead ECG), from which heart rate, heart rate variability, and PQ and QT intervals can be established in freeroaming, untethered mice. We also present pre-operative procedures and protocols for post-operative intensive care and pain treatment that improve recovery, well-being and survival rates in implanted mice5, 6.  相似文献   
25.
Bioleaching is a technology applicable to metal extraction from low-grade ores, ore beneficiation, coal beneficiation, metal detoxification, and recovery of metals from waste materials. The technology is environmentally sound and it may lower operational cost and energy requirement. Whereas leaching of sulfidic minerals using chemolithoautotrophic bacteria is the most studied and commercially exploitable aspect of mineral biotechnology today, there is a dearth of literature on the dissolution of nonsulfidic minerals. Biohydrometallurgy of nonsulfidic minerals involves the action of heterotrophic microorganisms. Heterotrophic bacteria and fungi have the potential for producing acidic metabolites that are able to solubilize oxide, silicate, carbonate and hydroxide minerals by reduction, acidolysis and complexation mechanisms. It is an important aspect of biohydrometallugy that requires development to meet future needs.  相似文献   
26.
This paper deals with the botanical study of a family funerary enclosure located in the Porta Nocera necropolis in Pompeii (southwestern Italy). This study is part of a Franco-Italian programme investigating Roman funerary rituals. The choice of the context was due to the exceptional preservation of the archaeological features, which offered the opportunity to observe the remains of the proceedings which took place in a funerary enclosure in great detail. An adequate methodology had to be developed and a 3D recording of every single artefact or ecofact has been made. Both ground surfaces and graves provided botanical results. Those from the ground surfaces consisted mainly of fruit offering residues (especially fig and grape), while a much wider range of species was observed in the tombs, including cereals, pulses, other kinds of fruits, weeds and bread/pastry. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   
27.
Andrij Baumketner 《Proteins》2012,80(12):2701-2710
Upon ATP binding, myosin motor protein is found in two alternative conformations, prerecovery state M* and postrecovery state M**. The transition from one state to the other, known as the recovery stroke, plays a key role in the myosin functional cycle. Despite much recent research, the microscopic details of this transition remain elusive. A critical step in the recovery stroke is the rotation of the converter domain from “up” position in prerecovery state to “down” position in postrecovery state that leads to the swing of the lever arm attached to it. In this work, we demonstrate that the two rotational states of the converter domain are determined by the interactions within a small structural motif in the force‐generating region of the protein that can be accurately modeled on computers using atomic representation and explicit solvent. Our simulations show that the transition between the two states is controlled by a small helix (SH1) located next to the relay helix and relay loop. A small translation in the position of SH1 away from the relay helix is seen to trigger the transition from “up” state to “down” state. The transition is driven by a cluster of hydrophobic residues I687, F487, and F506 that make significant contributions to the stability of both states. The proposed mechanism agrees well with the available structural and mutational studies. Proteins 2012; © 2012 Wiley Periodicals, Inc.  相似文献   
28.
A novel bioreactor with an internal adsorbent was developed for the simultaneous fermentation and recovery of prodigiosin-like pigment produced from Serratia sp. KH-95 as a model product in one bioreactor. The pigment concentration recovered in the internal adsorbent was 13.1 g l–1, which was 1.8-fold higher than that obtained in a bioreactor with an external adsorbent.  相似文献   
29.
Bearded seal (Erignathus barbatus) calls were recorded using autonomous passive acoustic recorders deployed in the northeastern Chukchi Sea between October 2007 and October 2010. Continuous acoustic data were acquired during summer (August to mid‐October), and overwinter data (mid‐October through July) were acquired on a duty cycle of 40/48 min every 4 h. We investigated the spatio‐temporal distribution and acoustic behavior of vocalizing bearded seals in this multiyear data set. Peaks in calling occurred in spring, coinciding with the mating period, and calls stopped abruptly in late June/early July. Fewer calls were detected in summer, and the vocal presence of seals increased with the formation of pack ice in winter. Vocal activity was higher at night than during the day, with a peak around 0400 (AKST). Monthly patterns in proportional use of each call type and call duration were examined for the first time. The proportion and duration of AL1(T) and AL2(T) call types increased during the mating period, suggesting that males advertise their breeding condition by producing those specific longer trills. The observed seasonal and diel trends were consistent between years. These results improve our understanding of occurrence and acoustic behavior of bearded seals across the northeastern Chukchi Sea.  相似文献   
30.
目的:探讨影响前臂屈指肌腱修复术后功能恢复效果的因素,以利于制定合理的手术及康复方案。方法:对2011年1月~2012年10月解放军第401医院手外科收治的58例(其中男性41例,女性17例,年龄13-62岁,平均33.8岁)屈指肌腱在前臂损伤患者的伤因及手术方式进行回顾、分析总结并进行随访,分析其受伤严重程度、手术方式、术后功能锻炼情况。结果:术后随访54例,失访4例,随访时间为术后3~6个月。根据中华医学会手外科学会手功能评定试用标准评定54例前臂屈指肌腱损伤修复术后的患手的恢复情况,其中优31例,良16例,中5例,差2例。指浅、深屈肌腱同时损伤较单纯指浅屈肌腱损伤修复术后粘连发生率较高,手功能的优良率较低(P0.05),合理应用防粘连技术和术后进行系统功能锻炼的患者术后手功能的优良率分别较未合理应用防粘连技术和术后未进行系统功能锻炼的患者显著升高(P0.05)。结论:手术切口是否合理的延长,术中操作是否重视无创操作,是否合理的应用防粘连技术以及缺乏系统的功能锻炼以及肌腱断端吻合质量是影响前臂屈指肌腱修复术后功能恢复的重要因素。  相似文献   
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