2,246 research outputs found
Upsilon Production In pp Collisions For Forward Rapidities At LHC
This is a continuation of recent studies of production at the
LHC in pp collisions. Our previous studies were for rapidity y=-1 to 1 for the
CMS detector, while the present study is for y=2.5 to 4.0 at the LHC.Comment: 5 pages, 2 figure
On the role of AGN feedback on the thermal and chemodynamical properties of the hot intra-cluster medium
We present an analysis of the properties of the ICM in an extended set of
cosmological hydrodynamical simulations of galaxy clusters and groups performed
with the TreePM+SPH GADGET-3 code. Besides a set of non-radiative simulations,
we carried out two sets of simulations including radiative cooling, star
formation, metal enrichment and feedback from supernovae, one of which also
accounts for the effect of feedback from AGN resulting from gas accretion onto
super-massive black holes. These simulations are analysed with the aim of
studying the relative role played by SN and AGN feedback on the general
properties of the diffuse hot baryons in galaxy clusters and groups: scaling
relations, temperature, entropy and pressure radial profiles, and ICM chemical
enrichment. We find that simulations including AGN feedback produce scaling
relations that are in good agreement with X-ray observations at all mass
scales. However, our simulations are not able to account for the observed
diversity between CC and NCC clusters: unlike for observations, we find that
temperature and entropy profiles of relaxed and unrelaxed clusters are quite
similar and resemble more the observed behaviour of NCC clusters. As for the
pattern of metal enrichment, we find that an enhanced level of iron abundance
is produced by AGN feedback with respect to the case of purely SN feedback. As
a result, while simulations including AGN produce values of iron abundance in
groups in agreement with observations, they over-enrich the ICM in massive
clusters. The efficiency of AGN feedback in displacing enriched gas from halos
into the inter-galactic medium at high redshift also creates a widespread
enrichment in the outskirts of clusters and produces profiles of iron abundance
whose slope is in better agreement with observations.Comment: 23 pages, 14 figures, 1 table, accepted for publication in MNRA
Cosmological hydrodynamical simulations of galaxy clusters: X-ray scaling relations and their evolution
We analyse cosmological hydrodynamical simulations of galaxy clusters to
study the X-ray scaling relations between total masses and observable
quantities such as X-ray luminosity, gas mass, X-ray temperature, and .
Three sets of simulations are performed with an improved version of the
smoothed particle hydrodynamics GADGET-3 code. These consider the following:
non-radiative gas, star formation and stellar feedback, and the addition of
feedback by active galactic nuclei (AGN). We select clusters with , mimicking the typical selection of
Sunyaev-Zeldovich samples. This permits to have a mass range large enough to
enable robust fitting of the relations even at . The results of the
analysis show a general agreement with observations. The values of the slope of
the mass-gas mass and mass-temperature relations at are 10 per cent lower
with respect to due to the applied mass selection, in the former case,
and to the effect of early merger in the latter. We investigate the impact of
the slope variation on the study of the evolution of the normalization. We
conclude that cosmological studies through scaling relations should be limited
to the redshift range , where we find that the slope, the scatter, and
the covariance matrix of the relations are stable. The scaling between mass and
is confirmed to be the most robust relation, being almost independent of
the gas physics. At higher redshifts, the scaling relations are sensitive to
the inclusion of AGNs which influences low-mass systems. The detailed study of
these objects will be crucial to evaluate the AGN effect on the ICM.Comment: 24 pages, 11 figures, 5 tables, replaced to match accepted versio
Biotecnologias aplicadas à reprodução de ovinos e caprinos.
A criação de caprinos e ovinos é uma atividade agropecuária de elevada importância social, econômica e consolidada em determinadas regiões do Brasil, enquanto em outras, mostra-se em fase emergente. Diversos aspectos apontam para o desenvolvimento desta cadeia produtiva no país. Dentre eles, a produção nacional, especialmente de carne e leite, sequer abastece o mercado interno, mesmo considerando que o consumo ainda é reduzido em relação a outros países. Em função da qualidade e diferencial dos produtos de origem caprina e ovina, acredita-se que em pouco tempo a demanda aumentará expressivamente, requerendo sistemas de criação focados na produtividade. Assim, torna-se fundamental desenvolver e adequar tecnologias voltadas ao incremento produtivo. Para tanto, recursos humanos, meio ambiente, nutrição, sanidade, bem-estar animal, genética e reprodução devem estar e operar concomitantemente. Dentre eles, a eficiência reprodutiva desempenha papel de destaque. A reprodução animal é uma área de intensos estudos, avanços e que vem sendo cada vez mais explorada em seu aspecto aplicado. Neste cenário, as biotécnicas oferecem benefícios singulares ao incremento reprodutivo. Todavia, o sucesso apenas é alcançado quando são empregadas diante do conhecimento holístico da área. Esta obra poderá auxiliar na consolidação e domínio de estudantes, profissionais e técnicos acerca das biotecnologias aplicadas à reprodução em ovinos e caprinos. O material apresenta inicialmente informações de aspectos fisiológicos que possibilitam ao leitor o entendimento das biotécnicas aplicadas detalhadamente abordadas em sequência. São apresentados os métodos de sincronização e indução de estro e ovulação; inseminação artificial; múltipla ovulação e transferência de embriões; e tecnologia reprodutivas avançadas como a produção in vitro de embriões, transgênese e clonagem.bitstream/item/133578/1/Livro-Biotecnologias-aplicadas-completo.pd
Transcervical embryo recovery in Lacaune ewes superovulated with different doses of FSH.
This study assessed the effect of different FSH dosages for superovulation and the feasibility of transcervical embryo recovery in Lacaune ewes. Ewes (n = 2 5) received 60 mg medroxiprogesterone acetate sponge (Progespon®, Syntex, Buenos Aires, Argentina) for nine days, 37.5 μg d-cloprostenol i.m. (Prolise®, Tecnopec, São Paulo, Brazil) 24 h before sponge removal and 50 μg gonadorelin (GnRH analogue, Gestran®, Tecnopec, São Paulo, Brazil) 24 h after sponge removal. The protocol for cervical relaxation was efficient to allow the transcervical embryo recovery of Lacaune ewes
The influence of different methods of frozen-thawed ovine spermatozoa selection on sperm capacitation and viability after incubation.
Abstract: Sperm capacitation is an essential event for fertilization; however, it decreases the sperm lifespan and viability. The aim of this study was to evaluate the effects of four sperm selection techniques on sperm capacitation and viability after incubation. A pool of frozen-thawed sperm from 10 Santa Inês rams was used. The samples were submitted to one of the following sperm selection techniques: sperm washing, Percoll gradient, mini-Percoll gradient, Swim-up and control group. At mini-Percoll technique, was used 400 microliters of 90% and 45% gradients and a centrifugation at 500 xg for 5 minutes. In Percoll, was used 1 mL of each gradient and a centrifugation at 700 xg for 10 minutos. During Swim-up, the sperm was incubated in 1 ml of SPERM-TALP for 45 minutos in humidified atmosphere at 37.5oC. Finaly, at sperm washing the sample suffered centrifugation at 300 xg for 8 minutes, using SPERM-TALP. At the end of each treatment, the selected spermatozoa were incubated at 37oC for 1 h, 2 h, and 3 h. Viability was assessed using acridine orange-propidium iodide combination by computer-assisted sperm analysis. Capacitation status was evaluated using chlortetracycline staining and observed under epifluorescence microscopy. Data were analyzed by ANOVA, followed by Tukey test (P0.05) among Percoll (36%), mini-Percoll (34%) and Swim-up (30%), and were lower (P0,05) entre Percoll (36%), mini-Percoll (34%) e Swim-up (30%), as quais foram inferiores (P<0,05) ao grupo controle (47%) e lavagem por centrifugação (41%). A taxa de espermatozoides não capacitados foi superior (P<0,05) no momento 0 h (12%) e diminuiu após 3 h (1,5%), independentemente do método. Houve interação (P<0,05) entre intervalo de incubação e método na taxa de espermatozoides reagidos. O índice de reagidos foi menor (P<0,05) em 0 h (50%) e 1 h (53%) e maior após 3 h (64%). Percoll (60%) e mini-Percoll (61%) apresentaram maiores valores para reagidos (P<0,05) enquanto o controle apresentou o menor (49%). Observou-se interação (P<0,05) entre intervalo de incubação e método na vitalidade espermática. A taxa de íntegros em 0 h foi a maior (17,5%; P<0,05), após os diferentes métodos. O Swim-up apresentou maior taxa de íntegros (17,4%; P<0,05), independentemente do intervalo de incubação. Em conclusão, o intervalo de incubação interfere nos padrões de capacitação e vitalidade de espermatozoides ovinos congelados. A seleção espermática aumenta a taxa de células reagidas e o Swim-up permite maior vitalidade durante a incubação.Proceedings of the 29th Annual Meeting of the Brazilian Embryo Technology Society (SBTE); Gramado, RS, Brazil, August 20 to 23, 2015. Abstracts
Investigating the properties of AGN feedback in hot atmospheres triggered by cooling-induced gravitational collapse
Radiative cooling may plausibly cause hot gas in the centre of a massive
galaxy, or galaxy cluster, to become gravitationally unstable. The subsequent
collapse of this gas on a dynamical timescale can provide an abundant source of
fuel for AGN heating and star formation. Thus, this mechanism provides a way to
link the AGN accretion rate to the global properties of an ambient cooling
flow, but without the implicit assumption that the accreted material must have
flowed onto the black hole from 10s of kiloparsecs away. It is shown that a
fuelling mechanism of this sort naturally leads to a close balance between AGN
heating and the radiative cooling rate of the hot, X-ray emitting halo.
Furthermore, AGN powered by cooling-induced gravitational instability would
exhibit characteristic duty cycles (delta) which are redolent of recent
observational findings: delta is proportional to L_X/sigma_{*}^{3}, where L_X
is the X-ray luminosity of the hot atmosphere, and sigma_{*} is the central
stellar velocity dispersion of the host galaxy. Combining this result with
well-known scaling relations, we deduce a duty cycle for radio AGN in
elliptical galaxies that is approximately proportional to M_{BH}^{1.5}, where
M_{BH} is the central black hole mass. Outburst durations and Eddington ratios
are also given. Based on the results of this study, we conclude that
gravitational instability could provide an important mechanism for supplying
fuel to AGN in massive galaxies and clusters, and warrants further
investigation.Comment: Accepted for publication in MNRAS. 8 page
Comparison of stress and animal welfare caused by the procedures of embryo collection by either surgical or non-surgical via in sheep.
In ovine species, embryo collection is commonly done by laparotomy (LP). However, this technique promotes adhesions in the reproductive organs leading to fertility impairment and affecting animal welfare. The non-surgical method, done by transcervical route (TC), although less invasive and expensive, can also affect animal welfare due to the cervix mechanical manipulation. In this perspective, biochemical markers of inflammation, as acute phase proteins, are considered reliable parameters of the systemic response to inflammatory processes
Transition Radiation Spectra of Electrons from 1 to 10 GeV/c in Regular and Irregular Radiators
We present measurements of the spectral distribution of transition radiation
generated by electrons of momentum 1 to 10 GeV/c in different radiator types.
We investigate periodic foil radiators and irregular foam and fiber materials.
The transition radiation photons are detected by prototypes of the drift
chambers to be used in the Transition Radiation Detector (TRD) of the ALICE
experiment at CERN, which are filled with a Xe, CO2 (15 %) mixture. The
measurements are compared to simulations in order to enhance the quantitative
understanding of transition radiation production, in particular the momentum
dependence of the transition radiation yield.Comment: 18 pages, 15 figures, submitted to Nucl. Instr. Meth. Phys. Res.
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