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101.
102.
McEwen AS Ojha L Dundas CM Mattson SS Byrne S Wray JJ Cull SC Murchie SL Thomas N Gulick VC 《Science (New York, N.Y.)》2011,333(6043):740-743
Water probably flowed across ancient Mars, but whether it ever exists as a liquid on the surface today remains debatable. Recurring slope lineae (RSL) are narrow (0.5 to 5 meters), relatively dark markings on steep (25° to 40°) slopes; repeat images from the Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment show them to appear and incrementally grow during warm seasons and fade in cold seasons. They extend downslope from bedrock outcrops, often associated with small channels, and hundreds of them form in some rare locations. RSL appear and lengthen in the late southern spring and summer from 48°S to 32°S latitudes favoring equator-facing slopes, which are times and places with peak surface temperatures from ~250 to 300 kelvin. Liquid brines near the surface might explain this activity, but the exact mechanism and source of water are not understood. 相似文献
103.
Morell V 《Science (New York, N.Y.)》2008,320(5872):44-45
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Rodolfo Ungerfeld Sergio Kmaid Fernando Baldi Virginia Salveraglio 《Reproduction in domestic animals》2021,56(5):783-791
The first aim of this study was to determine the influence of the procedures [hormonal treatments for fixed time artificial insemination (FTAI) versus insemination at spontaneous oestrus (SEAI)] on several sequential inseminations (AI). A second aim was to determine the influence of some intrinsic and extrinsic factors and their interactions, including characteristics of the animals such as age, season, farm, sire, and AI technician on the response to both procedures. A retrospective analysis was performed from a data base of 120.807 AIs of healthy cows with at least 40–70 days post-partum at first service. Overall, FTAI achieved slighter greater pregnancy rates than insemination after detected oestrus. The second AI seems to be a key insemination as effects of sire and technician were greater than in the following ones. The use of FTAI or SEAI in one AI did not affect the results of the following AIs, regardless if FTAI or SEAI procedures were used in that AI. Technician had greater variation than sire or farm on final pregnancy rate. The results of each sire for pregnancy rate varied according to the type of insemination, with sires achieving greater results with one or other procedure. Pregnancy rate was positively related to the days in milk in the first two AIs. Results were greater in autumn than in spring services. 相似文献
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Patricia Delgado Daniel Piñero Virginia Rebolledo Lev Jardón Francisco Chi 《Annals of Forest Science》2011,68(1):121-128
• Introduction
The recognition of endangered species takes into account geographic isolation and small size of populations, as is the case of two populations of Pinus caribaea var. hondurensis distributed in México. 相似文献109.
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Moran G Buechner-Maxwell VA Folch H Henriquez C Galecio JS Perez B Carrasco C Barria M 《Veterinary research communications》2011,35(7):447-456
Recurrent airway obstruction (RAO, also known as equine heaves) is an inflammatory condition similar to human asthma caused
by exposure of susceptible horses to poorly ventilated stable environments. The disease is characterized by neutrophilic airway
inflammation, mucus hypersecretion and reversible bronchoconstriction. This inflammatory process is mediated by several factors,
including antibodies, cytokines, resident cells of the airway and inflammatory cellular components that arrive in the respiratory
tract. An increasing body of evidence has lent support to the concept that a dysregulation of T cell apoptosis may play a
central role in the development of airway inflammation and the associated asthma. Therefore, the aim of this study was to
investigate early and late apoptosis of CD4 and CD8 T cell subpopulations obtained from the airways of acute RAO-positive
animals after exposure to hay/straw. The percentages of CD4 and CD8 T cells and their associated frequencies of apoptosis
were quantified using flow cytometry. Hay/straw exposure induced clinical airway obstruction, airway neutrophilia and increased
airway mucus production in RAO-positive horses. In addition, allergen exposure increased the percentage of CD4 T cells in
RAO-positive horses as well as the frequency of early and late apoptosis in both CD4 and CD8 lymphocyte subpopulations. These
results suggest that the higher frequency of lymphocyte apoptosis may play a role in disease progression of horses afflicted
with RAO and may partially explain the characteristic remission of this pathological condition once the allergen source is
removed. However, further studies are needed to clarify the role of T cell apoptosis in RAO-affected horses. 相似文献