2,567 research outputs found
Finite-size scaling considerations on the ground state microcanonical temperature in entropic sampling simulations
In this work we discuss the behavior of the microcanonical temperature
obtained by means of numerical entropic
sampling studies. It is observed that in almost all cases the slope of the
logarithm of the density of states is not infinite in the ground state,
since as expected it should be directly related to the inverse temperature
. Here we show that these finite slopes are in fact due to
finite-size effects and we propose an analytic expression for the
behavior of when . To
test this idea we use three distinct two-dimensional square lattice models
presenting second-order phase transitions. We calculated by exact means the
parameters and for the two-states Ising model and for the and
states Potts model and compared with the results obtained by entropic sampling
simulations. We found an excellent agreement between exact and numerical
values. We argue that this new set of parameters and represents an
interesting novel issue of investigation in entropic sampling studies for
different models
Peripheral Blood Leukocytes And Serum Nested Polymerase Chain Reaction Are Complementary Methods For Monitoring Active Cytomegalovirus Infection In Transplant Patients.
Human cytomegalovirus is an important cause of morbidity and mortality in immunocompromised patients. Qualitative polymerase chain reaction (PCR) has proven to be a sensitive and effective technique in defining active cytomegalovirus infection, in addition to having low cost and being a useful test for situations in which there is no need for quantification. Real-time PCR has the advantage of quantification; however, the high cost of this methodology makes it impractical for routine use. To apply a nested PCR assay to serum (sPCR) and to evaluate its efficiency to diagnose active cytomegalovirus infection compared with PCR of peripheral blood leukocytes (L-PCR). Samples of 37 patients were prospectively evaluated. An internal control was created and applied to sPCR to exclude false-negative results. In total, 21 patients (57%) developed active cytomegalovirus infection. After analyzing the two methods for the diagnosis of active infection, higher sensitivity and negative predictive value of the L-PCR versus sPCR (100% versus 62%), and higher specificity and positive predictive value of sPCR versus L-PCR (81% versus 50% and 72%, respectively) were observed. Discordant results were observed in 11 patients who were L-PCR-positive but sPCR-negative for active cytomegalovirus infection, five of whom developed clinical symptoms of cytomegalovirus. Clinical symptoms were observed in 14 patients, 12 of whom were diagnosed with active infection by nested L-PCR (P=0.007) and seven by nested sPCR (P=0.02). Higher specificity and a positive predictive value for sPCR were observed. Nested L-PCR and sPCR were considered to be complementary methods for the diagnosis and management of symptomatic cytomegalovirus infection.24e69-7
Characterisation of pulmonary function trajectories: results from a Brazilian cohort.
Background: Pulmonary function (PF) trajectories are determined by different exposures throughout the life course. The aim of this study was to investigate characteristics related to PF trajectories from 15 to 22 years in a Brazilian cohort. Methods: A birth cohort study (1993 Pelotas Birth Cohort) was conducted with spirometry at 15, 18 and 22 years. PF trajectories were built based on z-score of forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and their ratio using a group-based trajectory model. Associations with exposures reported from perinatal to 22 years were described. Results: Three trajectories, low (LT), average (AT) and high (HT) were identified in 2917 individuals. Wealthiest individuals belonged to the HT of FEV1 (p=0.023). Lower maternal pregestational body mass index (BMI) (22.4±0.2; p<0.001 and 22.1±0.14; p<0.001) and lower birth weight (3164.8±25.4; p=0.029 and 3132.3±19.4; p=0.005) were related to the LT of FEV1 and FVC. Mother's smoking exposure during pregnancy (37.7%; p=0.002), active smoking at ages 18 and 22 years (20.1% and 25.8%; p<0.001) and family history of asthma (44.8%; p<0.001) were related to the LT of FEV1/FVC. Wheezing, asthma and hospitalisations due to respiratory diseases in childhood were related to the LT of both FEV1 and FEV1/FVC. Higher BMIs were related to the HT of FEV1 and FVC at all ages. Conclusions: PF trajectories were mainly related to income, pregestational BMI, birth weight, hospitalisation due to respiratory diseases in childhood, participant's BMI, report of wheezing, medical diagnosis and family history of asthma, gestational exposure to tobacco and current smoking status in adolescence and young adult age
Change and Aging Senescence as an adaptation
Understanding why we age is a long-lived open problem in evolutionary
biology. Aging is prejudicial to the individual and evolutionary forces should
prevent it, but many species show signs of senescence as individuals age. Here,
I will propose a model for aging based on assumptions that are compatible with
evolutionary theory: i) competition is between individuals; ii) there is some
degree of locality, so quite often competition will between parents and their
progeny; iii) optimal conditions are not stationary, mutation helps each
species to keep competitive. When conditions change, a senescent species can
drive immortal competitors to extinction. This counter-intuitive result arises
from the pruning caused by the death of elder individuals. When there is change
and mutation, each generation is slightly better adapted to the new conditions,
but some older individuals survive by random chance. Senescence can eliminate
those from the genetic pool. Even though individual selection forces always win
over group selection ones, it is not exactly the individual that is selected,
but its lineage. While senescence damages the individuals and has an
evolutionary cost, it has a benefit of its own. It allows each lineage to adapt
faster to changing conditions. We age because the world changes.Comment: 19 pages, 4 figure
Successful therapeutic response of resistant cases of mucocutaneous leishmaniasis to a very low dose of antimony
Introduction: “Engaging with the writings of Denise Ferreira da Silva”
This is the final version. Available from Berghahn Journals via the DOI in this record. This interdisciplinary forum convenes a wide-ranging conversation centred around the writings of Denise Ferreira da Silva, whose unrelenting
inquiry locates the workings of raciality in the very constitution of the
modern subject, and, relatedly, global and historical consciousness. Da
Silva’s excavation of raciality is consequently expansive in its implications and fundamental in its focus. Throughout her oeuvre, including
Unpayable Debt (2022) and Toward a Global Idea of Race (2007), the crucial
role of ‘law’ in legitimizing the modern, global racial and economic
order remains a central problem. Da Silva’s decolonial agenda will meet
with immediate sympathy from many in anthropology – a discipline
that has engaged in sustained auto-critique of its own complicity in
racialized colonial rule for decades (see Asad 1975; Lewis 1973; Pels and
Salemink 2000; for a contemporary instance, cf. Price 2011). However, da
Silva shows that any narrow focus on specifc direct linkages to related
problematics of knowledge production occludes the constitutive role of
modern subjectivity in the globalization of modern juridical rule itself.
The ambition of da Silva’s excavation addresses, among other things,
such recurring questions for legal anthropology as: ‘who has law and
in what sense can diferent populations be said to have law?’; ‘how has
the idea of “law” helped to reproduce the very world wrought by the
post-Enlightenment?’; and ‘How might we test the limits of law?
Tissue Localization and Extracellular Matrix Degradation by PI, PII and PIII Snake Venom Metalloproteinases: Clues on the Mechanisms of Venom-Induced Hemorrhage
20 páginas, 4 figuras, 3 tablas y 7 tablas en material suplementario.Snake venom hemorrhagic metalloproteinases (SVMPs) of the PI, PII and PIII classes were compared in terms of tissue localization and their ability to hydrolyze basement membrane components in vivo, as well as by a proteomics analysis of exudates collected in tissue injected with these enzymes. Immunohistochemical analyses of co-localization of these SVMPs with type IV collagen revealed that PII and PIII enzymes co-localized with type IV collagen in capillaries, arterioles and post-capillary venules to a higher extent than PI SVMP, which showed a more widespread distribution in the tissue. The patterns of hydrolysis by these three SVMPs of laminin, type VI collagen and nidogen in vivo greatly differ, whereas the three enzymes showed a similar pattern of degradation of type IV collagen, supporting the concept that hydrolysis of this component is critical for the destabilization of microvessel structure leading to hemorrhage. Proteomic analysis of wound exudate revealed similarities and differences between the action of the three SVMPs. Higher extent of proteolysis was observed for the PI enzyme regarding several extracellular matrix components and fibrinogen, whereas exudates from mice injected with PII and PIII SVMPs had higher amounts of some intracellular proteins. Our results provide novel clues for understanding the mechanisms by which SVMPs induce damage to the microvasculature and generate hemorrhage.This work was performed in partial fulfillment of the requirements for the PhD degree for Cristina Herrera at Universidad de Costa Rica.Peer reviewe
Correlation between the heterosis of maize hybrids and genetic divergence among lines
The objective of this work was to evaluate grain yield of maize single cross hybrids obtained from diallel crosses among contrasting lines, to estimate the combining ability of the lines, and finally to confirm if the genetic diversity among those lines assessed by molecular markers is correlated with single cross hybrids heterosis. The 36 single cross hybrids resulting from partial diallel and 12 parental lines were evaluated in Campinas in randomized block design, with three replicates and two control lines checks. General combining ability of the lines was estimated according to Griffing model 4. Correlations among matrices were estimated through Mantel statistics, considering heterosis, yield and specific combining ability with genetic divergence assessed by AFLP and SSR. The hybrids PM518 x L111 exhibited an outstanding yield and the lines PM518, IP4035 and L111 showed positive general combining ability. The estimate heterosis ranged from 927 to 6,698 kg ha(-1). A positive and significant correlation was observed in parental lines between heterosis and genetic diversity assessed by AFLP and SSR. The genetic divergence, however, was not enough to determine the specific combining ability and the hybrids yield.42681181
A New Preconditioning Approachfor an Interior Point–Proximal Method of Multipliers for Linear and Convex Quadratic Programming
In this paper, we address the efficient numerical solution of linear and
quadratic programming problems, often of large scale. With this aim, we devise
an infeasible interior point method, blended with the proximal method of
multipliers, which in turn results in a primal-dual regularized interior point
method. Application of this method gives rise to a sequence of increasingly
ill-conditioned linear systems which cannot always be solved by factorization
methods, due to memory and CPU time restrictions. We propose a novel
preconditioning strategy which is based on a suitable sparsification of the
normal equations matrix in the linear case, and also constitutes the foundation
of a block-diagonal preconditioner to accelerate MINRES for linear systems
arising from the solution of general quadratic programming problems. Numerical
results for a range of test problems demonstrate the robustness of the proposed
preconditioning strategy, together with its ability to solve linear systems of
very large dimension
First report of Lutzomyia (Nyssomyia) umbratilis Ward & Frahia, 1977 outside of Amazonian Region, in Recife, State of Pernambuco, Brazil (Diptera: Psychodidae: Phlebotominae)
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