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971.
为了解宁夏贺兰山岩羊的种群现状,2020-2021年的8月和12-1月,在宁夏贺兰山国家级自然保护区运用样线法对岩羊(Pseudois nayaur)进行种群数量调查,利用R 4.0.1中的Distance 1.0.2对样线观测数据进行分析,估测保护区内岩羊的种群数量及密度,分析其种群结构。结果显示,夏季岩羊种群数量为5176(2554-10490)只,种群密度为2.674(1.320-5.420)只/km2;冬季岩羊种群数量为15752(7294-34017)只,种群密度为8.139(3.769-17.58)只/km2;多数观测距离样线垂直距离在0-200 m之内。岩羊主要集群形式:夏季为雌幼群(52.17%);冬季为混合群(26.60%)。岩羊平均群大小:夏季为(6.261±8.023)只,冬季为(4.064±4.229)只,群大小在不同季节的差异显著(P=0.010),集群大小多集中于1-5只之间,最大为47只。夏季调查中,雄性个体占比11.27%,雌性个体占比56.74%,幼体/亚成体占比31.99%;冬季调查中,雄性个体占比29.61%,雌性个体占比50.15%,幼体/亚成体占比20.24%;夏季和冬季岩羊组成成分之间差异极显著(P<0.001)。 相似文献
972.
Species often confront changing resource distributions that result from natural and anthropogenic processes. For species that reproduce on or in close association with particular resources (e.g. host plants), changing resource distributions could affect the success of mate finding. We examine how mate-finding behaviours in an herbivorous insect mediate the impact of changing host plant spatial distribution. We tracked movements of 84 Melissa blue butterflies (Lycaeides melissa) in the Great Basin of western North America. Track data revealed sex differences in movement: males spent more time moving fast and females more time moving slowly; males moved more ballistically and females moved more diffusely. These differences vary quantitatively, but not qualitatively, between environments with contrasting resource distributions.From these data we created and parameterised a computer model of male–female encounters and used it to examine implications of changes to the patchiness and abundance of host plants. We use the cumulative encounter time between each simulated male–female pair as a proxy for mating success, thus allowing for the consideration of different female behaviours. The simulations suggest observed movement parameters exist in a trade-off between individuals maximising the number of potential mates they encounter and the probability that each encounter leads to mating success. Increasing host plant abundance decreases encounter rates thus encouraging males to be more diffuse to compensate. Changing the local resource density, i.e. increasing host plant patchiness, accentuated these trade-offs: by decreasing cumulative encounter time in resource rich environments and increasing it in resource sparse ones. Thus we see that both spatial resource geometry at multiple scales and plasticity in male movement strategies are important factors to consider when seeking to understand population reproductive behaviour, for example when assessing ecological impact of development, determining range boundaries and slowing invasions or outbreaks. 相似文献
973.
Cleiton Silva Santos Everton Cruz de Azevedo Luciane Marieta Soares Magda Oliveira Seixas Carvalho Andréia Carvalho dos Santos Adenizar Delgado das Chagas Júnior Caroline Luane Rabelo da Silva Ursula Maira Russo Chagas Mitermayer Galv?o dos Reis Daniel Abensur Athanazio 《Memórias do Instituto Oswaldo Cruz》2013,108(4):438-445
Leptospirosis in humans usually involves hypokalaemia and
hypomagnesaemia and the putative mechanism underlying such ionic imbalances may
be related to nitric oxide (NO) production. We previously demonstrated the
correlation between serum levels of NO and the severity of renal disease in
patients with severe leptospirosis. Methylene blue inhibits soluble guanylyl
cyclase (downstream of the action of any NO synthase isoforms) and was recently
reported to have beneficial effects on clinical and experimental sepsis. We
investigated the occurrence of serum ionic changes in experimental leptospirosis
at various time points (4, 8, 16 and 28 days) in a hamster model. We also
determined the effect of methylene blue treatment when administered as an
adjuvant therapy, combined with late initiation of standard antibiotic
(ampicillin) treatment. Hypokalaemia was not reproduced in this model: all of
the groups developed increased levels of serum potassium (K). Furthermore,
hypermagnesaemia, rather than magnesium (Mg) depletion, was observed in this
hamster model of acute infection. These findings may be associated with an
accelerated progression to acute renal failure. Adjuvant treatment with
methylene blue had no effect on survival or serum Mg and K levels during
acute-phase leptospirosis in hamsters. 相似文献
974.
975.
G. R. VERHEYEN B. KEMPENAERS T. BURKE M. VAN DEN BROECK C. VAN BROECKHOVEN A. DHONDT 《Molecular ecology》1994,3(2):137-143
We report the isolation of a set of hypervariable minisatellite DNA sequences from a blue tit Parus caeruleus genomic DNA library. In our strategy, we cloned a minisatellite-rich DNA fraction into a charomid vector. The resulting cosmid library was screened with the two minisatellite DNA probes 33.6 and 33.15 for recombinants containing a minisatellite DNA insert. A total of 233 positive clones were isolated. Of 37 clones that have been analysed, nine gave polymorphic signals and can be used as single locus probes (SLPs). Four of the SLPs were investigated in more detail. The number of alleles, the heterozygosity and the mutation rate were estimated. Linkage analysis revealed that two of these loci were linked. The SLPs are of value to studies of the mating system and reproductive success in the blue tit, and may also be useful in population genetic studies. 相似文献
976.
Paul Jerem Katherine Herborn Dominic McCafferty Dorothy McKeegan Ruedi Nager 《Journal of visualized experiments : JoVE》2015,(105)
Stress, a central concept in biology, describes a suite of emergency responses to challenges. Among other responses, stress leads to a change in blood flow that results in a net influx of blood to key organs and an increase in core temperature. This stress-induced hyperthermia is used to assess stress. However, measuring core temperature is invasive. As blood flow is redirected to the core, the periphery of the body can cool. This paper describes a protocol where peripheral body temperature is measured non-invasively in wild blue tits (Cyanistes caeruleus) using infrared thermography. In the field we created a set-up bringing the birds to an ideal position in front of the camera by using a baited box. The camera takes a short thermal video recording of the undisturbed bird before applying a mild stressor (closing the box and therefore capturing the bird), and the bird’s response to being trapped is recorded. The bare skin of the eye-region is the warmest area in the image. This allows an automated extraction of the maximum eye-region temperature from each image frame, followed by further steps of manual data filtering removing the most common sources of errors (motion blur, blinking). This protocol provides a time series of eye-region temperature with a fine temporal resolution that allows us to study the dynamics of the stress response non-invasively. Further work needs to demonstrate the usefulness of the method to assess stress, for instance to investigate whether eye-region temperature response is proportional to the strength of the stressor. If this can be confirmed, it will provide a valuable alternative method of stress assessment in animals and will be useful to a wide range of researchers from ecologists, conservation biologists, physiologists to animal welfare researchers. 相似文献
977.
The state of water contained in emulsions, particularly in o/w emulsions, was studied as a model of water orientation at the peripheries of biomembranes. Dielectric measurements made at microwave frequency on emulsions containing water and liquid paraffin in various ratios with emulsifiers revealed that the o/w emulsions possessed considerably reduced dielectric loss as compared with theoretical values obtained in accordance with the Maxwell-Wagner model, while the dielectric properties of w/o emulsion were in good agreement with the theoretically expected values. The observations seem to be explained by assuming changes in the state of water in the oil-water interfacial layer in o/w emulsions. The preparation of stable emulsions for use in this study is also discussed. 相似文献
978.
《Biotechnic & histochemistry》2013,88(3):116-118
Rodent embryo double skeletal staining has long played a role in toxicological studies and is now an important part of selected genetic studies involving knockout or transgenic animals. However, phenotypic changes are sometimes not seen until animals reach adulthood. This study expands a previously developed embryonic staining method for use with adult mice. 相似文献
979.
980.
Incandescent lighting in many domestic and commercial applications is in the process of replacement by more efficient light sources, such as the compact fluorescent light (CFL) and the light emitting diode (LED). For household use, both CFL and LED sources have a significant blue component in the emitted spectrum in comparison to the warmer incandescent globes and this has been the cause of emerging health concerns. Recent research suggests that the blue light bandwidth in the visible spectrum has a significant impact on physical health, including disruption of the internal body clock and suppression of melatonin secretion at night. This disruptive effect has been linked to a range of illnesses, including breast cancer, prostate cancer, heart disease, obesity, and diabetes. There have also been positive effects observed, including re-setting the body clock to the required sleep pattern, boosting mood, alertness, cognitive performance, and alleviating seasonal affective depression (SAD). In this article, an introduction and review of recent research is provided, relevant health issues are highlighted and discussed, and uncertainty analysis completed for the dose–response curve for melatonin suppression as a function of incident photon density. 相似文献