34 research outputs found
Soybean lecithin-based extender as an alternative for goat sperm cryopreservation
AbstractThe aim of this study was to evaluate the effect of different concentrations of soybean lecithin (SL) in extenders for sperm goat cryopreservation. Sexually mature male Saanen goats (n=4) were used, and the ejaculates were obtained using an artificial vagina method. The semen samples were pooled and diluted in a skim milk-based extender (control group; CG) or Tris extender supplemented with SL at different concentrations (G1=0.04%, SL G2=0.08% SL and G3=0.16%) for a final concentration of 240Ă106spermatozoa/mL. The semen samples were packed in straws (0.25mL), frozen using an automated system and stored in liquid nitrogen (â196°C). After thawing (37°C/30s), the samples were evaluated for sperm quality parameters, including sperm motility, membrane integrity, acrosome integrity and mitochondrial activity. No significant difference was observed among the experimental and control groups for all of the parameters (P>0.05). However, even though the control group presented a significantly lower mitochondrial membrane potential compared to fresh semen (P<0.05), the same did not occur for the extender supplemented with soybean lecithin, that is, it did not differ from fresh sperm (P>0.05). The extender containing soybean lecithin at different concentrations preserved the sperm quality parameters in a manner similar to the conventional skim milk-based extender. Thus, it is concluded that an extender containing soybean lecithin as the lipoprotein source can be used for freezing goat semen
Pathways and mechanisms of offshore water intrusions on the EspĂrito Santo Basin shelf (18°Sâ22°S, Brazil)
Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 121 (2016): 5134â5163, doi:10.1002/2015JC011468.The pathways and physical mechanisms associated with intrusions of cold, nutrient-rich South Atlantic Central Water (SACW) on the continental shelf of the EspĂrito Santo Basin (ESB), off southeast Brazil (18°Sâ22°S), are investigated. To this end, a set of process-oriented, Primitive-Equation (PE) numerical models are used, together with an independent and more complete PE model, available observations and simple theoretical ideas. SACW enters the model ESB shelf mostly through two preferential pathways along the TubarĂŁo Bight (TB, 19.5°Sâ22°S). These pathways are found to be locations where an equatorward along-isobath pressure gradient force (PGFy*) of inline image m sâ2) develops in response to steady wind forcing. This equatorward PGFy* is essentially in geostrophic balance, inducing onshore flow across the shelf edge, and most of the shelf proper. The Brazil Current (BC) imparts an additional periodic (in the along-shelf direction) PGFy* on the shelf. The intrinsic pycnocline uplifting effect of the BC in making colder water available at the shelf edge is quantified. The BC also induces local intrusions by inertially overshooting the shelf edge, consistent with estimated Rossby numbers of inline image0.3â0.5. In addition, the planetary ÎČ-effect is related to a background equatorward PGFy*. A modified Arrested Topographic Wave model is shown to be a plausible rationalization for the shelf-wide spreading of the pressure field imparted by the BC at the shelf edge. The deep-ocean processes examined here are found to enhance the onshore transport of SACW, while wind forcing is found to dominate it at leading order.The first author acknowledges support
from the S~ao Paulo Research
Foundation (Fundacž~ao de Amparo a
Pesquisa do Estado de S~ao Paulo,
FAPESP), via grants 2013/11465â4 and
2014/03451â6. Kenneth Brink
acknowledges support from NSF
(grant OCE-1433953). Ilson da Silveira
acknowledges support from FAPESP
08/58101â9, CNPq 3071122/2010â7,
and CAPES 2201/2014. Wilton Arruda
acknowledges support from CNPq
(MCTI/CNPq/Universal 14/2014, grant
443162/2014â0), and from INCTâMarâ
COI, MCTI/CNPq grant 565062/2010â7.
Renato Martins acknowledges support
from Petr oleo Brasileiro S/A (AMBES
Project, PTâ133.01.10636).2017-01-3
Molecular detection of Mycobacterium bovis in cattle herds of the state of Pernambuco, Brazil
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Previous issue date: 2016-02-20Fundação Oswaldo Cruz. Instituto Aggeu MagalhĂŁes. Recife, PE, BrasilThe present study aimed to direct detect Mycobacterium bovis in milk (nâ=â401) and blood (nâ=â401) samples collected from 401 dairy cows of 20 properties located in the state of Pernambuco, Brazil, by real-time quantitative PCR (qPCR) targeting the region of difference 4 (RD4). Risk factors possibly associated with bovine tuberculosis (BTB) were also evaluated
Inquérito sorológico e fatores de riscos associados a ovinos soropositivos a Leptospira spp. no estado de Sergipe, Brasil
O objetivo desse estudo foi determinar a ocorrĂȘncia e os fatores associados Ă soropositividade para Leptospira spp. em ovinos do estado de Sergipe, Brasil, a partir de 1.200 amostras coletadas de sessenta propriedades das suas trĂȘs mesorregiĂ”es entre os anos de 2011 e 2012. Foi observada, pela reação de soroaglutinação microscĂłpica, 37,7% (452/1.200; IC: 0.357-0.396) de ovinos soropositivos com 93,3% (56) de propriedades com pelo menos um animal positivo. Os sorogrupos reagentes predominantes foram: Sejroe (32,1%), Icterohaemorrhagiae (23,5%) e Grippotyphosa (22,4%), com presença tambĂ©m de reaçÔes para Australis (7,1%), Pomona (3,8%), Autumnalis (3,5%), Panama (3,3%), Ballum (1,8%), Andamana (1,3%), Hebdomadis (0,9%) e Seranga (0,4%). As titulaçÔes variaram de 100 a 3.200, sendo que 77,2% delas ? 400. Os fatores associados Ă presença de ovinos soropositivos a Leptospira spp. foram: criaçÔes de subsistĂȘncia (p=0,000, OR=3,08, IC95%=1,99-4,78) e com finalidade de produção de matrizes e reprodutores (p=0,000, OR=2,19, IC95%=1,46-3,28). As infecçÔes por Leptospira spp. estĂŁo ostensivamente presentes nos rebanhos ovinos do estado de Sergipe, sendo necessĂĄria a adoção de prĂĄticas de manejo adequadas, direcionadas ao controle de roedores e criação consorciada com bovinos que podem levar a contaminação dos alimentos e pastagens
A New Model of Current Retroflection Applied to the Westward Protrusion of the Agulhas Current
Sea Level Anomaly trends in the South Atlantic around 10\ub0S
In this work, we analyze regional trends of altimetric Sea Level Anomalies (SLA), and the contribution of the steric component. We show evidences that for the region around 10oS, the steric component cannot explain the altimetric SLA trends. On the western side of the region, the altimetric SLA trend is positive, while the steric component of the SLA has a negative trend. In the eastern side, both trends are positive, but the steric contribution is too small. Although the steric component of the SLA cannot explain regional trends of altimetric SLA, it is able to explain 45% of the decrease of subtropical gyre northward transport.Pages: 7200-720
Temperature and Salinity trends in the South Atlantic
Recent studies indicate that the Agulhas leakage increased in the last decades due to the poleward shift of westerlies, what contributed to the observed warming of the Agulhas Current system and salinification of the South Atlantic thermocline waters. In this work we show that there is an unequal increasing in temperature and salinity in different areas of the South Atlantic, but there is no doubt that it getting warm and salty. A fraction of the warm and salty waters injected into the South Atlantic by the Agulhas leakage remains in the South Atlantic while the rest of it is transmitted to the North Atlantic as part of the thermocline return flow of the AMOC.Pages: 7890-789
Variabilidade da Piscina Quente do AtlĂąntico Tropical
Analisando dados de ĂĄrea e volume da Piscina Quente do AtlĂąntico Tropical (PQAT), derivados a partir de um modelo de gravidade reduzida, observamos que essas grandezas apresentam um trend linear relacionado a elevação do nĂvel dos mares. Retirando das sĂ©ries a melhor aproximação linear, obtivemos sĂ©ries de anomalias de ĂĄrea e volume da PQAT. ComparaçÔes com dados de Temperatura da SuperfĂcie do Mar (TSM) indicam que a variabilidade das anomalias de ĂĄrea da PQAT estĂŁo altamente correlacionadas com as anomalias de TSM tanto em escala anual, quanto em escala interanual. Em escala interanual, as sĂ©ries de anomalias de ĂĄrea e volume da PQAT, assim como de anomalias de TSM, apresentam um pico de energia no perĂodo de 4.9 anos, e picos secundĂĄrios nos perĂodos de 2.5 e 1.8 anos. Assim, apresentamos evidĂȘncias indicando que a variabilidade interanual da PQAT pode ser explicada pela variabilidade de TSM.Pages: 7192-719
The arrested Agulhas retroflection
Paleoceanographic proxy data indicate that the Agulhas leakage into the South Atlantic was dramatically reduced during glacial times. In our former papers, we suggested that this was due to a northward shift of the zero wind stress curl that, in turn, forced the retroflection to occur farther north, where the slant of the coastline relative to the north is steep. In the present paper, we propose that strong westerlies (0.4 Pa, implying a wind speed of âŒ12 m sâ1 at zero degrees centigrade), which were supposedly common during glaciations, can also arrest the leakage. This arrest occurred because the wind stress opposed the momentum flux associated with the retroflection; such an arrest did not require the retroflection to shift in latitude.We use a simple, nonlinear, âreduced gravityâ model to show analytically and numerically that, under the above conditions, the eastward wind stress compensates for the zonal westward flow-force associated with the retroflection, thus avoiding the development and shedding of rings. For a nearly zonal wall, westerly winds, and small upper layer thickness along the wall, thearresting wind stress is found, theoretically, to be, Ï x = 0.042α3/2 Ïf0 [(2f0Q) 3 /gâČ]1/4, whereα is twice the retroflection eddy vorticity, Ï is the water density, Q is the Agulhas Current volume flux, and the remaining notation is conventional