326 research outputs found
Embedding a Native State into a Random Heteropolymer Model: The Dynamic Approach
We study a random heteropolymer model with Langevin dynamics, in the
supersymmetric formulation. Employing a procedure similar to one that has been
used in static calculations, we construct an ensemble in which the affinity of
the system for a native state is controlled by a "selection temperature" T0. In
the limit of high T0, the model reduces to a random heteropolymer, while for
T0-->0 the system is forced into the native state. Within the Gaussian
variational approach that we employed previously for the random heteropolymer,
we explore the phases of the system for large and small T0. For large T0, the
system exhibits a (dynamical) spin glass phase, like that found for the random
heteropolymer, below a temperature Tg. For small T0, we find an ordered phase,
characterized by a nonzero overlap with the native state, below a temperature
Tn \propto 1/T0 > Tg. However, the random-globule phase remains locally stable
below Tn, down to the dynamical glass transition at Tg. Thus, in this model,
folding is rapid for temperatures between Tg and Tn, but below Tg the system
can get trapped in conformations uncorrelated with the native state. At a lower
temperature, the ordered phase can also undergo a dynamical glass transition,
splitting into substates separated by large barriers.Comment: 19 pages, revtex, 6 figure
Comparison of the functional and structural characteristics of rare TSC2 variants with clinical and genetic findings
The TSC1 and TSC2 gene products interact to form the tuberous sclerosis complex (TSC), an important negative regulator of the mechanistic target of rapamycin complex 1 (TORC1). Inactivating mutations in TSC1 or TSC2 cause TSC, and the identification of a pathogenic TSC1 or TSC2 variant helps establish a diagnosis of TSC. However, it is not always clear whether TSC1 and TSC2 variants are inactivating. To determine whether TSC1 and TSC2 variants of uncertain clinical significance affect TSC complex function and cause TSC, in vitro assays of TORC1 activity can be employed. Here we combine genetic, functional, and structural approaches to try and classify a series of 15 TSC2 VUS. We investigated the effects of the variants on the formation of the TSC complex, on TORC1 activity and on TSC2 pre-mRNA splicing. In 13 cases (87%), the functional data supported the hypothesis that the identified TSC2 variant caused TSC. Our results illustrate the benefits and limitations of functional testing for TSC
CaracterĂsticas morfolĂłgicas e estudo da vascularização do corpo lĂşteo cĂclico de cabras ao longo do ciclo estral
Corpus luteum is a temporary endocrine gland that regulates either the estrous cycle and pregnancy. It presents extreme dependency on the adequate blood supply. This work aims to evaluate goat corpus luteum (CL) vascular density (VD) over the estrous cycle. For that purpose, 20 females were submitted to estrus synchronization/ovulation treatment using a medroxyprogesterone intra-vaginal sponge as well as intramuscular (IM) application of cloprostenol and equine chorionic gonadotrophine (eCG). After sponge removal, estrus was identified at about 72hs. Once treatment was over, female goats were then subdivided into 4 groups (n=5 each) and slaughtered on days 2, 12, 16 and 22 after ovulation (p.o). Ovaries were collected, withdrawn and weighted. CL and ovaries had size and area recorded. Blood samples were collected and the plasma progesterone (P4) was measured through RIA commercial kits. The VD was 24.42Âą6.66, 36.26Âą5.61, 8.59Âą2.2 and 3.97Âą1.12 vessels/mm² for days 2, 12, 16 and 22 p.o, respectively. Progesterone plasma concentrations were 0.49Âą0.08, 2.63Âą0.66, 0.61Âą0.14 and 0.22Âą0.04ng/ml for days 2, 12, 16 e 22 p.o, respectively. Studied parameters were affected by the estrous cycle phase. Values greater than 12 p.o were observed. In the present work we observed that ovulation occurred predominantly in the right ovary (70% of the animals), which in turn presented bigger measures than the contra lateral one. There is a meaningful relationship between the weight and size of the ovary and these of CL (r=0.87, r=0.70, respectively, p<0.05). It is possible to conclude that morphology of goat's ovaries and plasma progesterone concentration changed according to estrous cycle stages. We propose these parameters can be used as indicators of CL functional activity.O corpo lĂşteo ĂŠ uma glândula endĂłcrina temporĂĄria que regula tanto o ciclo estral quanto a prenhez, apresentando extrema dependĂŞncia de aporte sanguĂneo adequado. Objetivaram-se avaliar mudanças morfomĂŠtricas dos ovĂĄrios e densidade vascular (DV) dos corpos lĂşteos (CL) de cabras ao longo do ciclo estral (AOLC). Vinte animais foram submetidos ao tratamento para indução/sincronização do estro, usando esponjas intravaginais commedroxiprogesterona, associadas a aplicaçþes intramusculares de cloprostenol e gonadotrofina coriĂ´nica eqĂźina. ApĂłs remoção das esponjas, o estro foi identificado em aproximadamente de 72h. ConcluĂdo o tratamento, as cabras foram subdivididas em 4 grupos (n=5 cada) para abate nos dias 2, 12, 16 e 22 apĂłs ovulação (p.o.). Posteriormente, foram retirados os ovĂĄrios e realizadas as mensuraçþes de peso, tamanho e ĂĄrea do ĂłrgĂŁo e dos CL. Amostras de sangue foram coletadas e a progesterona sĂŠrica (P4) mensurada utilizando-se RIA convencional. A DV mĂŠdia dos CL AOLC foi 24,42Âą6,66; 36,26Âą5,61; 8,59Âą2,2 e 3,97Âą1,12 vasos/mm2 para os dias 2, 12, 16 e 22 p.o., respectivamente. A concentração mĂŠdia de P4 foi de 0,49Âą0,08; 2,63Âą0,66; 0,61Âą0,14 e 0,22Âą0,04ng/ml para os dias 2, 12, 16 e 22 p.o., respectivamente. Os parâmetros em estudo tambĂŠm se mostraram afetados pela fase do ciclo estral, sendo observados os maiores (p < 0,05) valores no dia 12 p.o. Neste experimento, a ovulação ocorreu predominantemente no ovĂĄrio direito (70% dos animais), o qual apresentou medidas maiores que o contralateral. Observou-se ainda alta correlação significativa entre o peso do ovĂĄrio e o do CL (r=0,87; p<0,05) e entre o tamanho destes ĂłrgĂŁos (r=0,70; p<0,05). Conclui-se que, a morfologia dos ovĂĄrios de cabras e a concentração sĂŠrica de progesterona variam em função da fase do ciclo estral e podem ser utilizadas como parâmetro na avaliação funcional do ĂłrgĂŁo
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
Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV
The Lambda(b) differential production cross section and the cross section
ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum
pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7
TeV using data collected by the CMS experiment at the LHC. The measurements are
based on Lambda(b) decays reconstructed in the exclusive final state J/Psi
Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and
Lambda to proton pion, using a data sample corresponding to an integrated
luminosity of 1.9 inverse femtobarns. The product of the cross section times
the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls
faster than that of b mesons. The measured value of the cross section times the
branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06
+/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for
anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are
statistical and systematic, respectively.Comment: Submitted to Physics Letters
Scarabaeoidea (Insecta : Coleoptera) in the Brazilian Cerrado : current state of knowledge
Besouros pertencentes Ă superfamĂlia Scarabaeoidea ocupam habitats variados, possuem hĂĄbitos alimentares diversifi cados, desempenham importante papel ecolĂłgico e diversas espĂŠcies apresentam importância agrĂcola. No entanto, estudos com esse grupo na regiĂŁo do Cerrado sĂŁo escassos. Nesta revisĂŁo realizou-se um levantamento dos artigos publicados nos Ăşltimos 30 anos a respeito dos Scarabaeoidea no Cerrado. Foram recuperados 64 artigos, realizados em nove unidades da federação, que focavam quatro temas principais espĂŠcies praga, aspectos bioecolĂłgicos, biodiversidade e importância ecolĂłgica, e tĂŠcnicas e metodologias de coleta de Scarabaeoidea. Os resultados desta revisĂŁo indicam que poucos estudos foram realizados com os Scarabaeoidea no Cerrado brasileiro nas Ăşltimas dĂŠcadas frente Ă importância e diversidade desse grupo de insetos.Beetles belonging to the superfamily Scarabaeoidea occupy different habitats, present feeding habits diversifi ed, play an important ecological role and several species have agricultural importance. However, studies with this group in the Brazilian Cerrado are scarce. In this review we carried out a survey of scientifi c articles published in the past 30 years concerning Scarabaeoidea in the Cerrado. Were found 64 studies in nine Brazilian states. The studies focused on four main topics: pest species, bioecology, biodiversity and ecological importance, techniques and methodologies for collecting Scarabaeoidea. The results of this review indicate that few studies have been conducted with Scarabaeoidea in the Cerrado in recent decades compared to the importance and diversity of this group of insects
Measurement of isolated photon production in pp and PbPb collisions at sqrt(sNN) = 2.76 TeV
Isolated photon production is measured in proton-proton and lead-lead
collisions at nucleon-nucleon centre-of-mass energies of 2.76 TeV in the
pseudorapidity range |eta|<1.44 and transverse energies ET between 20 and 80
GeV with the CMS detector at the LHC. The measured ET spectra are found to be
in good agreement with next-to-leading-order perturbative QCD predictions. The
ratio of PbPb to pp isolated photon ET-differential yields, scaled by the
number of incoherent nucleon-nucleon collisions, is consistent with unity for
all PbPb reaction centralities.Comment: Submitted to Physics Letters
Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at sqrt(s) = 7 TeV
A search is presented for physics beyond the standard model (BSM) in final
states with a pair of opposite-sign isolated leptons accompanied by jets and
missing transverse energy. The search uses LHC data recorded at a
center-of-mass energy sqrt(s) = 7 TeV with the CMS detector, corresponding to
an integrated luminosity of approximately 5 inverse femtobarns. Two
complementary search strategies are employed. The first probes models with a
specific dilepton production mechanism that leads to a characteristic kinematic
edge in the dilepton mass distribution. The second strategy probes models of
dilepton production with heavy, colored objects that decay to final states
including invisible particles, leading to very large hadronic activity and
missing transverse energy. No evidence for an event yield in excess of the
standard model expectations is found. Upper limits on the BSM contributions to
the signal regions are deduced from the results, which are used to exclude a
region of the parameter space of the constrained minimal supersymmetric
extension of the standard model. Additional information related to detector
efficiencies and response is provided to allow testing specific models of BSM
physics not considered in this paper.Comment: Replaced with published version. Added journal reference and DO
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