Effective Rheology of Bubbles Moving in a Capillary Tube

We calculate the average volumetric flux versus pressure drop of bubbles moving in a single capillary tube with varying diameter, finding a square-root relation from mapping the flow equations onto that of a driven overdamped pendulum. The calculation is based on a derivation of the equation of motion of a bubble train from considering the capillary forces and the entropy production associated with the viscous flow. We also calculate the configurational probability of the positions of the bubbles.Comment: 4 pages, 1 figur

Effects of gustatory stimulation on the behavioral states of premature newborns

OBJETIVO: Observar os estados comportamentais apresentados por recém-nascidos prematuros a partir de oferta de estímulos gustativos. MÉTODOS: Estudo experimental, analítico, duplo cego. Participaram 90 recém-nascidos prematuros nascidos em uma maternidade pública de Sergipe. O teste foi filmado, dividido em três etapas de cinco minutos. Na primeira e na última, não houve estímulo; na segunda aconteceu estimulação gustativa, sendo que os recém-nascidos foram divididos em dois grupos (água ou sacarose para análise 12%). Os estados comportamentais observados foram sono profundo, sono leve, sonolento, alerta, irritado/agitado e choro. Os dados foram analisados estatisticamente. RESULTADOS: No grupo sacarose houve correlação forte nos estados comportamentais sono leve e alerta, durante e após a estimulação, e redução de correlação nos estados sonolento, agitado/irritado e choro. Já no grupo água, após a estimulação houve aumento de correlação nos estados agitado/irritado e choro. CONCLUSÃO: A permanência ou mudança do estado comportamental do recém-nascido prematuro foi influenciada positivamente pela administração de estímulo gustativo, apontando para o possível uso da sacarose na contribuição de estados comportamentais favoráveis nessa população. _________________________________________________________________________________________ ABSTRACT: Purpose: To observe the behavioral states presented by premature new-borns in response to gustatory stimulation. Methods: Experimental, analytical and double-blind study. Ninety premature newborns born in a public maternity hospital in Sergipe took part in the test which was filmed and divided into three parts of five minutes. In the first and last, there was no stimulus; in the second, the gustatory stimulation was applied and the newborn children were divided into two groups (water or analysis for sucrose 12%). The observed behavioral states were deep sleep, light sleep, drowsy, alert, agitated/irritated and crying. The data were statistically analyzed. Results: In the sucrose group, during and after stimulation, the correlation was strong in the light sleep and alert behavioral states and decreased in the drowsy, agitated/irritated and crying states. In the water group there was an increase in correlation in the agitated/irritated and crying states after stimulation. Conclusion: The continuity or change of the behavioral state of the premature newborns was positively influenced by the administration of gustatory stimulus, pointing to the possibility of using sucrose in benefit of the favorable behavioral states of that population

Alignment of the ALICE Inner Tracking System with cosmic-ray tracks

37 pages, 15 figures, revised version, accepted by JINSTALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 micron in some cases (pixels). The sources of alignment information include survey measurements, and the reconstructed tracks from cosmic rays and from proton-proton collisions. The main track-based alignment method uses the Millepede global approach. An iterative local method was developed and used as well. We present the results obtained for the ITS alignment using about 10^5 charged tracks from cosmic rays that have been collected during summer 2008, with the ALICE solenoidal magnet switched off.Peer reviewe

Resolving the strange behavior of extraterrestrial potassium in the upper atmosphere

It has been known since the 1960s that the layers of Na and K atoms, which occur between 80 and 105 km in the Earth's atmosphere as a result of meteoric ablation, exhibit completely different seasonal behavior. In the extratropics Na varies annually, with a pronounced wintertime maximum and summertime minimum. However, K varies semiannually with a small summertime maximum and minima at the equinoxes. This contrasting behavior has never been satisfactorily explained. Here we use a combination of electronic structure and chemical kinetic rate theory to determine two key differences in the chemistries of K and Na. First, the neutralization of K+ ions is only favored at low temperatures during summer. Second, cycling between K and its major neutral reservoir KHCO3 is essentially temperature independent. A whole atmosphere model incorporating this new chemistry, together with a meteor input function, now correctly predicts the seasonal behavior of the K layer

Particle identification in ALICE : a Bayesian approach

Peer reviewe

Osteonecrosis of the femoral head in people living with HIV: anatomopathological description and p24 antigen test

Ana Lucia L Munhoz Lima,1 Priscila Rosalba Oliveira,1 Vladimir C Carvalho,1 Alexandre Leme Godoy-Santos,1 Leandro Ejnisman,1 Claudia R Oliveira,1 David E Uip,2 Maria Irma S Duarte3 1Instituto de Ortopedia e Traumatologia, Hospital das Clínicas HCFMUSP, Universidade de São Paulo, São Paulo, Brazil; 2Faculdade de Medicina da Fundacao do ABC, São Paulo, Brazil; 3Departamento de Patologia, Faculdade de Medicina FMUSP, Universidade de São Paulo, Sao Paulo, Brazil Objective: To examine the presence of HIV in bone tissue of people living with HIV (PLWHIV) with osteonecrosis of femoral head and describe clinical and anatomopathological findings.Design: This is a case series which included 44 PLWHIV with osteonecrosis of femoral head who underwent total hip arthroplasty.Methods: Clinical data were obtained through analysis of the patients’ medical records. Bone tissue obtained during total hip arthroplasty was retrieved and sent for conventional and immunohistochemical analysis. Monoclonal antibodies were used to mark the p24 (HIV), CD31 (vascular endothelial cells), CD68 (macrophages), and D240 (cells of the lymphatic endothelium) antigens.Results: Dyslipidemia was found in 48% of the patients and lipodystrophy in 31%. Histological analysis showed similar characteristics for the entire sample. Degeneration of joint cartilage was visualized with the presence of fissures and fibrillations, as well as subchondral sclerosis and necrosis of the subchondral cancellous bone tissue. Lymphoplasmocytic inflammatory reaction was observed, with the presence of macrophages containing a foamy, vacuolated cytoplasm, as well as the presence of ceroid pigment and occasional granulation tissue. The reaction with the monoclonal anti-p24 antibody was negative in the samples from all 44 PLWHIV undergoing hip arthroplasty. Reactions with the anti-CD31 and anti-D240 antibodies were negative. Staining with CD68 antibody confirmed that the cells visualized with foamy, vacuolated cytoplasm were macrophages.Conclusion: p24 HIV antigen was not detected in the bone tissue of PLWHIV and osteonecrosis. The most frequent anatomopathological findings were extensive necrosis of bone tissue, large vacuoles filled with fat cells, inflammatory lymphoplasmocytic reaction with macrophages containing vacuolated cytoplasm, and the presence of ceroid pigment. Keywords: osteonecrosis, AIDS, HIV core protein p24, immunohistochemistr

清涼飮料税論

The production of J/\).psi\) and $\psi(2S)$ was measured with the ALICE detector in Pb-Pb collisions at the LHC. The measurement was performed at forward rapidity 2.5 < y < 4 \() down to zero transverse momentum \(p_{\rm T} in the dimuon decay channel. Inclusive J/\).psi\) yields were extracted in different centrality classes and the centrality dependence of the average $p_{\rm T}$ is presented. The J/\).psi\) suppression, quantified with the nuclear modification factor $R_{\rm AA}$ , was studied as a function of centrality, transverse momentum and rapidity. Comparisons with similar measurements at lower collision energy and theoretical models indicate that the J/\).psi\) production is the result of an interplay between color screening and recombination mechanisms in a deconfined partonic medium, or at its hadronization. Results on the $\psi(2S)$ suppression are provided via the ratio of $\psi(2S)$ over J/\).psi\) measured in pp and Pb-Pb collisions