共查询到20条相似文献,搜索用时 640 毫秒
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Eva Persson Margret Wülbers-Mindermann Charlotte Berg Bo Algers 《Acta veterinaria Scandinavica》2008,50(1):24
Background
The natural feeding behaviour of the pig is searching for feed by rooting activities throughout the day; self-feeding pigs randomly space their eating and drinking periods throughout the day consuming ten to twelve meals per day. Pigs in conventional fattening pig production are normally fed 2–3 times daily with the feed consumed within 15 minutes. The aim of this study was to determine if more frequent feedings could improve the performance of conventionally kept fattening pigs. 相似文献3.
Ahlam Al-Ghamdi Serdar Coskun Saad Al-Hassan Rafat Al-Rejjal Khalid Awartani 《Reproductive biology and endocrinology : RB&E》2008,6(1):37
Background
To evaluate the relationship between endometrial thickness on day of human chorionic gonadotrophin administration (hCG) and pregnancy outcome in a large number of consecutive in vitro fertilization and embryo transfer (IVF-ET) cycles. 相似文献4.
Background
Objectives of the study were to document the impact of some management factors on the occurrence of clinical mastitis in primiparous dairy cows and to identify common udder pathogens of clinical mastitis in freshly calved heifers and multiparous cows on the day of calving. 相似文献5.
Jaime Esteban Nieves Z Martín-de-Hijas Teemu J Kinnari Guillermo Ayala Ricardo Fernández-Roblas Ignacio Gadea 《BMC microbiology》2008,8(1):184
Background
A study to evaluate the biofilm-development ability in three different media (Middlebrook 7H9, sterile tap water and PBS-5% glucose) was performed with 19 collection strains from 15 different species on non-pigmented rapidly growing mycobacteria (NPRGM). A microtiter plate assay was developed to evaluate the percentage of covered surface of the microtiter plate wells in different days from day 1 to day 69. 相似文献6.
Iyú D Atucha NM Martínez-Prieto C Ortiz MC García-Estañ J 《Cell communication and signaling : CCS》2004,2(1):1
Background
In the present study we have analyzed the mechanisms of calcium entry and mobilization in platelets obtained from rats chronically treated with the nitric oxide synthesis inhibitor, N-nitro L-arginine methyl ester [L-NAME, 40 mg/kg/day, 5 days). The platelets were obtained the day of the experiment, washed and loaded with fura-2. The intracellular calcium levels were determined in suspension of cells by means of fluorescence spectroscopy. 相似文献7.
Comparative analysis of proteome maps of silkworm hemolymph during different developmental stages 总被引:3,自引:0,他引:3
Yong Hou Yong Zou Fei Wang Jing Gong Xiaowu Zhong Qingyou Xia Ping Zhao 《Proteome science》2010,8(1):45
Background
The silkworm Bombyx mori is a lepidopteran insect with four developmental stages: egg, larva (caterpillar), pupa, and adult. The hemolymph of the silkworm is in an open system that circulates among all organs, and functions in nutrient and hormone transport, injury, and immunity. To understand the intricate developmental mechanisms of metamorphosis, silkworm hemolymph from different developmental stages, including the 3rd day of fifth instar, the 6th day of fifth instar, the 3rd day of pupation, the 8th day of pupal stage and the first day of the moth stage, was investigated by two-dimensional electrophoresis and mass spectrometry. 相似文献8.
Claudia Steglich Debbie Lindell Matthias Futschik Trent Rector Robert Steen Sallie W Chisholm 《Genome biology》2010,11(5):R54
Background
RNA turnover plays an important role in the gene regulation of microorganisms and influences their speed of acclimation to environmental changes. We investigated whole-genome RNA stability of Prochlorococcus, a relatively slow-growing marine cyanobacterium doubling approximately once a day, which is extremely abundant in the oceans. 相似文献9.
Yann Moalic Sophie Arnaud-Haond Cécile Perrin Gareth A Pearson Ester A Serrao 《BMC evolutionary biology》2011,11(1):33
Background
Hybridization or divergence between sympatric sister species provides a natural laboratory to study speciation processes. The shared polymorphism in sister species may either be ancestral or derive from hybridization, and the accuracy of analytic methods used thus far to derive convincing evidence for the occurrence of present day hybridization is largely debated. 相似文献10.
Past vegetation dynamics in the Yellowstone region highlight the vulnerability of mountain systems to climate change
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Virginia Iglesias Cathy Whitlock Teresa R. Krause Richard G. Baker 《Journal of Biogeography》2018,45(8):1768-1780
Aim
Reconstruct the long‐term ecosystem dynamics of the region across an elevational gradient as they relate to climate and local controls. In particular, we (1) describe the dominant conifers' history; (2) assess changes in vegetation composition and distribution; and (3) note periods of abrupt change versus stability as means of better understanding vegetation responses to environmental variability.Location
Greater Yellowstone Ecosystem (GYE; USA).Time period
16.5 ka bp ‐present.Major taxa studied
Juniperus, Picea, Abies, Pinus, Pseudotsuga.Methods
The vegetation reconstruction was developed from 15 pollen records. Results were interpreted based on modern pollen–vegetation relationships estimated from a suite of regression‐based approaches.Results
Calibrated pollen data suggest that late‐glacial vegetation, dominated by shrubs and Juniperus, lacks a modern counterpart in the area. Picea, Abies and Pinus expanded at 16 ka bp in association with postglacial warming and co‐occurred in mixed‐conifer parkland/forest after 12 ka bp . This association along with Pinus contorta forest, which was present after 9 ka bp , has persisted with little change at middle and high elevations to the present day. This stability contrasts with the dynamic history of plant communities at low elevations, where shifts between parkland, steppe and forest over the last 8,000 years were likely driven by variations in effective moisture and fire.Main conclusions
The postglacial vegetation history of the GYE highlights the dynamic nature of mountain ecosystems and informs on their vulnerability to future climate change: (1) most of the conifers have been present in the area for >12,000 years and survived climate change by adjusting their elevational ranges; (2) some plant associations have exhibited stability over millennia as a result of nonclimatic controls; and (3) present‐day forest cover is elevationally more compressed than at any time in history, probably due to the legacy of the Medieval Climate Anomaly and the Little Ice Age. 相似文献11.
Christopher L Douglas Vladyslav Vyazovskiy Teresa Southard Shing-Yan Chiu Albee Messing Giulio Tononi Chiara Cirelli 《BMC biology》2007,5(1):42
Background
Shaker codes for a Drosophila voltage-dependent potassium channel. Flies carrying Shaker null or hypomorphic mutations sleep 3–4 h/day instead of 8–14 h/day as their wild-type siblings do. Shaker-like channels are conserved across species but it is unknown whether they affect sleep in mammals. To address this issue, we studied sleep in Kcna2 knockout (KO) mice. Kcna2 codes for Kv1.2, the alpha subunit of a Shaker-like voltage-dependent potassium channel with high expression in the mammalian thalamocortical system. 相似文献12.
T.L. Buhr A.A. Young Z.A. Minter C.M. Wells D.C. McPherson C.L. Hooban C.A. Johnson E.J. Prokop J.R. Crigler 《Journal of applied microbiology》2012,113(5):1037-1051
Aims
To develop test methods and evaluate the survival of Bacillus anthracis ?Sterne and Bacillus thuringiensis Al Hakam spores after exposure to hot, humid air.Methods and Results
Spores (>7 logs) of both strains were dried on six different test materials. Response surface methodology was employed to identify the limits of spore survival at optimal test combinations of temperature (60, 68, 77°C), relative humidity (60, 75, 90%) and time (1, 4, 7 days). No spores survived the harshest test run (77°C, 90% r.h., 7 days), while > 6·5 logs of spores survived the mildest test run (60°C, 60% r.h., 1 day). Spores of both strains inoculated on nylon webbing and polypropylene had greater survival rates at 68°C, 75% r.h., 4 days than spores on other materials. Electron microscopy showed no obvious physical damage to spores using hot, humid air, which contrasted with pH‐adjusted bleach decontamination.Conclusions
Test methods were developed to show that hot, humid air effectively inactivates B. anthracis ?Sterne and B. thuringiensis Al Hakam spores with similar kinetics.Significance and Impact of the Study
Hot, humid air is a potential alternative to conventional chemical decontamination. 相似文献13.
Background
this study set out to examine the effects of the treatment with 1,25-dihydroxyvitamin D3 (1,25D 3) [150 IU/Kg (3.75 μg/Kg) one a day, for 15 days] to non-diabetic rats and in rats rendered diabetic by a single injection of streptozotocin [65 mg/kg]. 相似文献14.
Rong-Huan He Hui-Juan Gao Ya-Qiong Li Xiao-Ming Zhu 《Reproductive biology and endocrinology : RB&E》2010,8(1):46
Background
Endometrial cavity fluid (ECF) is a fluid accumulation within the endometrial cavity. The significance of ECF remains unclear during the program of in vitro fertilization-embryo transfer (IVF-ET). The aim of the present study was to investigate the associated factors to ECF, visualized through ultrasound at the day of oocyte retrieval, and the relevant impact on the outcome of IVF-ET. 相似文献15.
Background
While text-mining and distributed annotation systems both aim at capturing knowledge and presenting it in a standardized form, there have been few attempts to investigate potential synergies between these two fields. For instance, distributed annotation would be very well suited for providing topic focussed, expert knowledge enriched text corpora. A key limitation for this approach is the availability of literature annotation systems that can be routinely used by groups of collaborating researchers on a day to day basis, not distracting from the main focus of their work. 相似文献16.
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Olga V Savinova Fumihiro Sugiyama Janice E Martin Stanislav I Tomarev Beverly J Paigen Richard S Smith Simon WM John 《BMC genetics》2001,2(1):12-15
Background
Little is known about genetic factors affecting intraocular pressure (IOP) in mice and other mammals. The purpose of this study was to determine the IOPs of genetically distinct mouse strains, assess the effects of factors such as age, sex and time of day on IOP in specific strain backgrounds, and to assess the effects of specific candidate gene mutations on IOP. 相似文献20.