1,028 research outputs found
The potential effects and interactions of oxidative stress and trace minerals on fresh and frozen semen in bulls - a review
Reproduction is one of the most important factors determining successful cattle farming systems. Management practices, such
as nutritional supplementation, can influence the reproductive performance of cattle. The objective of this literature review is
to determine the potential value of injectable trace mineral administration on fresh and cryopreserved semen quality of bulls.
A search of keywords related to the topic was performed on published articles and textbooks. The search was narrowed to the
40 most relevant references.
Several studies have demonstrated a positive association between trace mineral supplementation and bull semen quality.
Moderate amounts of reactive oxygen species (ROS) play an important role in normal spermatogenesis, but oxidative stress (OS), as
experienced with adverse environmental conditions or disease, can contribute to idiopathic male infertility by negatively impacting
spermatogenesis. Trace minerals such as selenium, copper, zinc, and manganese have been demonstrated to have antioxidant
effects in mammals. Due to the complexity of oral ingested trace mineral bioavailability, injectable trace mineral supplementation
prior to physiological periods with known deficiencies or increased requirement can benefit the animal.
The potential benefits of injectable trace mineral supplementation to minimise oxidative damage to spermatogenesis in breeding
bulls need further investigation. Positive results from such studies can lead to the implementation of injectable trace mineral
supplementation strategies prior to the breeding season to minimise the detrimental effects of OS and can improve semen quality.http://www.jsava.co.zaam2023Production Animal Studie
Sazonalidade e Uso de Ambientes por Espécies de Tabanidae (Diptera) na Amazônia Central, Brasil
Adults of Tabanidae may become serious pests wherever they occur due to their attack to humans and others animals. Tabanids were captured near ground, water surface and at 25 m high on primary forests and forest gaps of anthropogenic origin, to understand their abundance, seasonality, diversity and similarity on such environments. Collections were carried out in the Base II of the War Instruction Center in the Jungle (CIGS) located at 54 km from Manaus municipality, Amazonas state. Two Malaise flight interception traps and four attraction traps (two suspended at 25 m high and two above the water surface of igarapé) were installed in forest gap and primary forest, areas for 10 consecutive days, during 15 months. A total of 2,643 specimens of 66 species were captured. Diachlorini (35 species /11 genera) was the most abundant tribe, followed by Tabanini (19 species /three genera), Chrysopsini (seven species /one genus) and Scionini (five species /two genera). Seventeen species were captured only in the primary forest, 11 in the anthropic clearing, and 38 species were common to both environments. The most abundant species were Phorcotabanus cinereus (Wiedemann), Tabanus occidentalis L, Chrysops laetus Fabricius and Tabanus angustifrons Macquart. The greatest richness was found in drier months (September/October) in both areas. The forest gap showed higher abundance of specimens (1,827) than the primary forest (816). Traps suspended above the water surface were the most efficient (1,723 specimens) probably due to the dispersion of horseflies over small streams
Role of dynamical particle-vibration coupling in reconciliation of the puzzle for spherical proton emitters
It has been observed that decay rate for proton emission from
single particle state is systematically quenched compared with the prediction
of a one dimensional potential model although the same model successfully
accounts for measured decay rates from and states. We
reconcile this discrepancy by solving coupled-channels equations, taking into
account couplings between the proton motion and vibrational excitations of a
daughter nucleus. We apply the formalism to proton emitting nuclei
Re to show that there is a certain range of parameter set of the
excitation energy and the dynamical deformation parameter for the quadrupole
phonon excitation which reproduces simultaneously the experimental decay rates
from the 2, 3 and 1 states in these nuclei.Comment: RevTex, 12 pages, 4 eps figure
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Volcanic constraints on the unzipping of Africa from South America: Insights from new geochronological controls along the Angola margin
The breakup of Africa from South America is associated with the emplacement of the Paraná-Etendeka flood basalt province from around 134 Ma and the Tristan da Cunha plume. Yet many additional volcanic events occur that are younger than the main pulse of the Paraná-Etendeka and straddle the rift to drift phases of the main breakup. This contribution reports on new geochronological constraints from the Angolan part of the African Margin. Three coastal and one inland section have been sampled stretching across some 400 Km, with 39Ar/40Ar, U-Pb and Palaeontology used to provide age constraints. Ages from the new data range from ~100 to 81 Ma, with three main events (cr. 100, 91 and 82-81 Ma). Volcanic events are occurring within the Early to Late Cretaceous, along this part of the margin with a general younging towards Namibia. With the constraints of additional age information both onshore and offshore Angola, a clear younging trend at the early stages of rift to drift is recorded in the volcanic events that unzip from North to South. Similar age volcanic events are reported from the Brazilian side of the conjugate margin, and highlight the need to fully incorporate these relatively low volume volcanic pulses into the plate tectonic breakup models of the South Atlantic Margin
Cytotoxicity of diplodiatoxin, dipmatol and diplonine, metabolites synthesized by Stenocarpella maydis
The cytotoxicity of three Stenocarpella maydis metabolites (diplodiatoxin, dipmatol and
diplonine) was investigated on Neuro-2a, CHO-K1 and MDBK cell lines. Diplodiatoxin was
the most cytotoxic followed by dipmatol. Conversely, diplonine was not cytotoxic. Diplodiatoxin
and dipmatol affected mitochondrial succinate dehydrogenase (MTT assay) and
the overall viability of cells as assessed in real-time (xCELLigence assay). The results obtained
so far indicate that diplodiatoxin and dipmatol exert their toxicity possibly via the
necrotic cell death pathway.National Research Foundation (NRF), International Foundation for
Science (IFS) and the Joy Liebenberg Trust Fund.http://www.elsevier.com/locate/toxiconhb201
Cosmology With Non-Minimally Coupled K-Field
We consider non-minimally coupled (with gravity) scalar field with
non-canonical kinetic energy. The form of the kinetic term is of
Dirac-Born-Infeld (DBI) form.We study the early evolution of the universe when
it is sourced only by the k-field, as well as late time evolution when both the
matter and k-field are present. For the k-field, we have considered constant
potential as well as potential inspired from Boundary String Field Theory
(B-SFT). We show that it is possible to have inflationary solution in early
time as well as late time accelerating phase. The solutions also exhibit
attractor property in a sense that it does not depend on the initial conditions
for a certain values of the parameters.Comment: 10 pages, Revtex style, 14 eps figures, to appear in General
Relativity and Gravitatio
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Geochronology of volcanically associated hydrocarbon charge in the pre-salt carbonates of the Namibe Basin, Angola
In volcanic rifted margins, the timing of hydrocarbon charge is difficult to predict, but is important in understanding fluid genesis. We investigated whether igneous activity was linked to hydrocarbon charge in the prolific South Atlantic pre-salt petroleum system. To do this, we applied in situ carbonate U-Pb geochronology, a relatively novel tool for dating hydrocarbon migration, to bituminous veins in pre-salt travertines from the rifted onshore Namibe Basin (Angola). To test if fluid flow was synchronous with known volcanic pulses, we also obtained new 40Ar/39/Ar geochronology from a nearby volcanic complex. Bitumen is associated with calcite in a first generation of veins and vugs, and with dolomite in younger veins. The dated calcite veins yielded a pooled U-Pb age of 86.2 ± 2.4 Ma, which overlaps the volcanism 40Ar/39/Ar age of 89.9 ± 1.8 Ma. The overlapping dates and the localized bitumen occurrence around the dated volcanic center show a clear genetic relationship between Late Cretaceous igneous activity and hydrocarbon charge. The dolomite was dated at 56.8 ± 4.8 Ma, revealing a previously unknown Paleocene/Eocene fluid-flow phase in the basin
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