576 research outputs found
Dynamic transition in driven vortices across the peak effect in superconductors
We study the zero-temperature dynamic transition from the disordered flow to
an ordered flow state in driven vortices in type-II superconductors. The
transition current is marked by a sharp kink in the
characteristic with a concomitant large increase in the defect concentration.
On increasing magnetic field , the follows the behaviour of the
critical current . Specifically, in the peak effect regime
increases rapidly along with . We also discuss the effect of varying
disorder strength on .Comment: 4 pages, 4 figure
Transverse depinning in strongly driven vortex lattices with disorder
Using numerical simulations we investigate the transverse depinning of moving
vortex lattices interacting with random disorder. We observe a finite
transverse depinning barrier for vortex lattices that are driven with high
longitudinal drives, when the vortex lattice is defect free and moving in
correlated 1D channels. The transverse barrier is reduced as the longitudinal
drive is decreased and defects appear in the vortex lattice, and the barrier
disappears in the plastic flow regime. At the transverse depinning transition,
the vortex lattice moves in a staircase pattern with a clear transverse
narrow-band voltage noise signature.Comment: 4 pages, 4 figure
V-I characteristics in the vicinity of order-disorder transition in vortex matter
The shape of the V-I characteristics leading to a peak in the differential
resistance r_d=dV/dI in the vicinity of the order-disorder transition in NbSe2
is investigated. r_d is large when measured by dc current. However, for a small
Iac on a dc bias r_d decreases rapidly with frequency, even at a few Hz, and
displays a large out-of-phase signal. In contrast, the ac response increases
with frequency in the absence of dc bias. These surprisingly opposite phenomena
and the peak in r_d are shown to result from a dynamic coexistence of two
vortex matter phases rather than from the commonly assumed plastic depinning.Comment: 12 pages 4 figures. Accepted for publication in PRB rapi
Solum depth spatial prediction comparing conventional with knowledge-based digital soil mapping approaches
Solum depth and its spatial distribution play an important role in different types of environmental studies. Several approaches have been used for fitting quantitative relationships between soil properties and their environment in order to predict them spatially. This work aimed to present the steps required for solum depth spatial prediction from knowledge-based digital soil mapping, comparing the prediction to the conventional soil mapping approach through field validation, in a watershed located at Mantiqueira Range region, in the state of Minas Gerais, Brazil. Conventional soil mapping had aerial photo-interpretation as a basis. The knowledge-based digital soil mapping applied fuzzy logic and similarity vectors in an expert system. The knowledge-based digital soil mapping approach showed the advantages over the conventional soil mapping approach by applying the field expert-knowledge in order to enhance the quality of final results, predicting solum depth with suited accuracy in a continuous way, making the soil-landscape relationship explicit
Performance of ALICE AD modules in the CERN PS test beam
Two modules of the AD detector have been studied with the test beam at the T10 facility at CERN. The AD detector is made of scintillator pads read out by wave-length shifters (WLS) coupled to clean fibres that carry the produced light to photo-multiplier tubes (PMTs). In ALICE the AD is used to trigger and study the physics of diffractive and ultra-peripheral collisions as well as for a variety of technical tasks like beam-gas background monitoring or as a luminometer. The position dependence of the modules' efficiency has been measured and the effect of hits on the WLS or PMTs has been evaluated. The charge deposited by pions and protons has been measured at different momenta of the test beam. The time resolution is determined as a function of the deposited charge. These results are important ingredients to better understand the AD detector, to benchmark the corresponding simulations, and very importantly they served as a baseline for a similar device, the Forward Diffractive Detector (FDD), being currently built and that will be in operation in ALICE during the LHC Runs 3 and 4.Peer reviewe
Phagosomal removal of fungal melanin reprograms macrophage metabolism to promote antifungal immunity
Acknowledgements This work was supported by the Northern Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER) (NORTE-01- 0145-FEDER-000013), the Fundação para a CiĂȘncia e Tecnologia (FCT) (SFRH/BD/136814/2018 to S.M.G., SFRH/BD/141127/2018 to C.D.O., PD/BD/137680/2018 to D.A., IF/00474/2014 to N.S.O., IF/01390/2014 to E.T., IF/00959/2014 to S.C., IF/00021/2014 to R.S., PTDC/SAU-SER/29635/2017 and CEECIND/04601/2017 to C.C., and CEECIND/03628/2017 to A.C.), the Institut MĂ©rieux (MĂ©rieux Research Grant 2017 to C.C.), and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID Research Grant 2017 to A.C.). M.G.N. was supported by a Spinoza grant of the Netherlands Organization for Scientific Research. A.A.B. was supported by the Deutsche Forschungsgemeinschaft Collaborative Research Center/Transregio TR124 FungiNet (project A1). G.D.B. was funded by the Wellcome Trust (102705), the MRC Centre for Medical Mycology and the University of Aberdeen (MR/N006364/1).Peer reviewedPublisher PD
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV
A search for a Higgs boson decaying into two photons is described. The
analysis is performed using a dataset recorded by the CMS experiment at the LHC
from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an
integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross
section of the standard model Higgs boson decaying to two photons. The expected
exclusion limit at 95% confidence level is between 1.4 and 2.4 times the
standard model cross section in the mass range between 110 and 150 GeV. The
analysis of the data excludes, at 95% confidence level, the standard model
Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The
largest excess of events above the expected standard model background is
observed for a Higgs boson mass hypothesis of 124 GeV with a local significance
of 3.1 sigma. The global significance of observing an excess with a local
significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is
estimated to be 1.8 sigma. More data are required to ascertain the origin of
this excess.Comment: Submitted to Physics Letters
Avaliação de dois mĂ©todos para condicionamento e coleta de sĂȘmen em quatro espĂ©cies do gĂȘnero Mazama
O desenvolvimento de tĂ©cnicas nĂŁo invasivas para a obtenção de sĂȘmen de cervĂdeos facilita a criação de bancos genĂŽmicos, que sĂŁo importantes instrumentos para a conservação ex situ e in situ. Este trabalho teve como objetivo criar uma metodologia nĂŁo-invasiva de coleta de sĂȘmen e comparar duas tĂ©cnicas de coleta em quatro espĂ©cies do gĂȘnero Mazama: M. americana, M. gouazoubira, M. nana e M. nemorivaga. Para tanto, foram utilizados seis machos (M) e duas fĂȘmeas (F) da espĂ©cie M. americana, 3M e 2F de M. gouazoubira, 1M e 1F de M. nana e 2M e 1F de M. nemorivaga. Para cada tĂ©cnica testada, foi realizado um perĂodo de habituação dos animais ao manejo. Em seguida, duas tĂ©cnicas de condicionamento e coleta foram avaliadas. Na primeira delas foi utilizada uma fĂȘmea em estro com desvio lateral do pĂȘnis para vagina artificial (FEDL), obtendo-se a coleta de 50% dos indivĂduos (100% dos machos de M. gouazoubira e 50% dos machos de M. americana), nĂŁo obtendo ejaculados das demais espĂ©cies. Na segunda tĂ©cnica, utilizando um manequim taxidermizado com urina de fĂȘmea em estro (MUFE) nĂŁo foi possĂvel a coleta de nenhum ejaculado. Em todas as fases foi observado o comportamento do macho quanto ao tempo de interesse e aproximação, reflexo de "Flehmen", ato de cheirar ou lamber, exposição do pĂȘnis, ereção, nĂșmero de falsas montas, tentativas de cĂłpula e ocorrĂȘncia de agressividade entre os animais
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