Dynamical Casimir effect for a massless scalar field between two concentric spherical shells with mixed boundary conditions

In this work we analyze the dynamical Casimir effect for a massless scalar field confined between two concentric spherical shells considering mixed boundary conditions. We thus generalize a previous result in literature [Phys. Rev. A 78, 032521 (2008)], where the same problem is approached for the field constrained to the Dirichlet-Dirichlet boundary conditions. A general expression for the average number of particle creation is deduced considering an arbitrary law of radial motion of the spherical shells. This expression is then applied to harmonic oscillations of the shells, and the number of particle production is analyzed and compared with the results previously obtained under Dirichlet-Dirichlet boundary conditions.

Dynamical Casimir effect for a massless scalar field between two concentric spherical shells

In this work we consider the dynamical Casimir effect for a massless scalar field-under Dirichlet boundary conditions-between two concentric spherical shells. We obtain a general expression for the average number of particle creation, for an arbitrary law of radial motion of the spherical shells, using two distinct methods: by computing the density operator of the system and by calculating the Bogoliubov coefficients. We apply our general expression to breathing modes: when only one of the shells oscillates and when both shells oscillate in or out of phase. Since our results were obtained in the framework of the perturbation theory, under resonant breathing modes they are restricted to a short-time approximation. We also analyze the number of particle production and compare it with the results for the case of plane geometry.

Effects of eccentric and concentric training on capillarization and myosin heavy chain contents in rat skeletal muscles after hindlimb suspension

We studied the effects of different protocols of post-disuse rehabilitation on angiogenesis and myosin heavy chain (MHC) content in rat hindlimb muscles after caudal suspension. Thirty female Wistar rats were divided into five groups: (1) Control I, (2) Control II, (3) Suspended, (4) Suspended trained on declined treadmill, and (5) Suspended trained on flat treadmill. Fragments of the soleus and tibialis anterior (TA) muscles were frozen and processed by electrophoresis and immunohistochemistry (CD31 antibody). Hindlimb suspension caused reduction of capillary/fiber (C/F) ratios and contents of MHC type I (MHCI) in the soleus in parallel to increased capillary density. Flat treadmill protocols increased the content of the MHCI isoform. The C/F ratio was increased by concentric training after hypokinesis, but was not modified by eccentric training, which caused a greater reduction of capillary density compared to the other protocols. In the TA muscle, hindlimb suspension caused a non-significant increase in capillary density and C/F ratio with limited changes in MHC. The present data demonstrate that the different training protocols adopted and the functional performance of the muscles analyzed caused specific changes in capillarization and in the content of the various MHC types. (C) 2010 Published by Elsevier GmbH.

Optimizing the nipple-areola sparing mastectomy with double concentric periareolar incision and biodimensional expander-implant reconstruction: Aesthetic and technical refinements

Although the biodimensional anatomical expander-implant system (BEIS) is a reliable technique, little information has been available regarding outcome following nipple-areola sparing mastectomy (NSM). To perform the resection of glandular tissue, while improving the surgical access and maintaining the nipple-areola vascularization we have developed a new approach for NSM based on the double concentric periareolar incision (DCPI). The purpose of this study is to analyze the feasibility, surgical planning and its outcome following NSM. 18 patients underwent NSM reconstructions. Mean time of follow-up was 29 months. The technique was indicated in patients with small/moderate volume breasts. Flap complications were evaluated and information on aesthetic results and patient satisfaction were collected. 83.3% had tumors measuring 2 cm or less (T1) and 72.1% were stage 0 and 1. All patients presented peripherally tumors located (at least 5 cm from the nipple). Skin complications occurred in 11.1%. One patient (5.5%) presented small skin necrosis and a wound dehiscence was observed in one patient (5.5%). The aesthetic result was good/very good in 94.4 percent and the majority of patients were very satisfied/satisfied. No local recurrences were observed. All complications except one were treated by a conservative approach. DCPI-BEIS is a simple and reliable technique for NSM reconstruction. The success depends on patient selection, coordinated planning with the oncologic surgeon and careful intra-operative and post-operative management. (C) 2009 Elsevier Ltd. All rights reserved.

A new Amphisbaena with chevron-shaped anterior body annuli from state of Pernambuco: Brazil (Squamata: Amphisbaenidae)

A new species of Amphisbaena is described from Fazenda Porto Seguro, municipality of Buique, state of Pernambuco, in the Caatingas of northeastern Brazil based on four specimens. The new species is a small and slender amphisbaenian with four precloacal pores, 333-337 body annuli, 22-23 tail annuli with discrete evidence of an autotomic site on the 10-12 tail annuli, and 14 dorsal and 17-18 ventral segments per annuli at midbody. The high number of body annuli, the presence of chevron-shaped anterior body annuli, and the fusion of frontal scales distinguish Amphisbaena supernumeraria sp. nov. from its congeners.

Concentric characterization and classification of complex network nodes: Application to an institutional collaboration network

Differently from theoretical scale-free networks, most real networks present multi-scale behavior, with nodes structured in different types of functional groups and communities. While the majority of approaches for classification of nodes in a complex network has relied on local measurements of the topology/connectivity around each node, valuable information about node functionality can be obtained by concentric (or hierarchical) measurements. This paper extends previous methodologies based on concentric measurements, by studying the possibility of using agglomerative clustering methods, in order to obtain a set of functional groups of nodes, considering particular institutional collaboration network nodes, including various known communities (departments of the University of Sao Paulo). Among the interesting obtained findings, we emphasize the scale-free nature of the network obtained, as well as identification of different patterns of authorship emerging from different areas (e.g. human and exact sciences). Another interesting result concerns the relatively uniform distribution of hubs along concentric levels, contrariwise to the non-uniform pattern found in theoretical scale-free networks such as the BA model. (C) 2008 Elsevier B.V. All rights reserved.

Forced convection to laminar flow of liquid egg yolk in circular and annular ducts

The steady-state heat transfer in laminar flow of liquid egg yolk - an important pseudoplastic fluid food - in circular and concentric annular ducts was experimentally investigated. The average convection heat transfer coefficients, determined by measuring temperatures before and after heating sections with constant temperatures at the tube wall, were used to obtain simple new empirical expressions to estimate the Nusselt numbers for fully established flows at the thermal entrance of the considered geometries. The comparisons with existing correlations for Newtonian and non-Newtonian fluids resulted in excellent agreement. The main contribution of this work is to supply practical and easily applicable correlations, which are, especially for the case of annulus, rather scarce and extensively required in the design of heat transfer operations dealing with similar shear-thinning products. In addition, the experimental results may support existing theoretical analyses.

Primary and secondary thickening in the stem of Cordyline fruticosa (Agavaceae)

The growth in thickness of monocotyledon stems can be either primary, or primary and secondary. Most of the authors consider this thickening as a result of the PTM (Primary Thickening Meristem) and the STM (Secondary Thickening Meristem) activity. There are differences in the interpretation of which meristem would be responsible for primary thickening. In Cordyline fruticosa the procambium forms two types of vascular bundles: collateral leaf traces (with proto and metaxylem and proto and metaphloem), and concentric cauline bundles (with metaxylem and metaphloem). The procambium also forms the pericycle, the outermost layer of the vascular cylinder consisting of smaller and less intensely colored cells that are divided irregularly to form new vascular bundles. The pericycle continues the procambial activity, but only produces concentric cauline bundles. It was possible to conclude that the pericycle is responsible for the primary thickening of this species. Further away from the apex, the pericyclic cells undergo periclinal divisions and produce a meristematic layer: the secondary thickening meristem. The analysis of serial sections shows that the pericycle and STM are continuous in this species, and it is clear that the STM originates in the pericycle.The endodermis is acknowledged only as the innermost layer of the cortex.

A new species of Neotropical freshwater stingray of the genus Potamotrygon Garman, 1877 from the Río Madrede Díos, Peru (Chondrichthyes: Potamotrygonidae)

Potamotrygon tatianae sp. nov., is described from Río Madre de Díos, Peru, upper Rio Madeira basin. The new species is distinguished from all congeners by a unique combination of characters, including its dorsal color pattern formed by a relatively slender, highly convoluted, beige to dark brown vermicular pattern, a single row of dorsal tail spines, and a relatively longer tail posterior to caudal stings. Potamotrygon tatianae sp. nov., occurs sympatrically with other species of Potamotrygon (P. falkneri, P. orbignyi and P. motoro). From the similar species P. falkneri, P. tatianae sp. nov., is further distinguished by the absence of circular, reniform, and oval spots, by its proportionally much longer tail, by having dorsal tail spines in one irregular row, and by features of the ventral lateral-line canal, dermal denticles and neurocranium. From P. orbignyi, the new species is distinct by lacking a reticulate pattern on dorsal disc and by the presence of two angular cartilages. From P. motoro, P. tatianae sp. nov., is further separated by the lack of ocelli formed by strong black concentric rings, by the more flattened aspect of its head and disc, and by having smaller and more numerous teeth. The discovery of a new species that so closely resembles a congeneric form in color pattern, a feature highly variable within the latter, highlights the importance of examining large series of individuals and of detailed morphological analyses in revealing the potentially highly cryptic nature of the diversity within the family.

Detecção de estímulos concêntricos mesópicos em crianças surdas e ouvintes

O objetivo deste trabalho foi medir curvas de sensibilidade ao contraste de 10 crianças ouvintes e de 10 crianças com surdez pré-lingual, de 7 a 12 anos, utilizando frequências radiais circularmente concêntricas (FSCr) de 0,25-2,0 cpg em níveis baixos de luminância (0,7 cd/m²). Todos os participantes apresentavam acuidade visual normal e estavam livres de doenças oculares identificáveis. A FSCr foi medida com o método psicofísico da escolha forçada. Os resultados mostraram sensibilidade máxima na faixa de frequência radial de 0,25 cpg para os dois grupos. Os resultados mostraram ainda diferenças significantes entre as curvas de FSCr de crianças ouvintes e de crianças com surdez pré-lingual. Isto é, as crianças ouvintes precisaram de menos contraste do que as crianças surdas para detectar as frequências radiais. Esses resultados sugerem que, em níveis baixos de luminância, a FSCr das crianças ouvintes foi melhor do que a das crianças com surdez pré-lingual.

Post-eccentric exercise blunted hGH response

The purpose of the present study was to test if a previous acute concentric exercise bout blunts hGH response after an eccentric exercise bout. Nine healthy untrained male university students (25.4 +/- 0.5 yr, 176.5 +/- 1.2 cm, and 79.4 +/- 2.0 kg) performed a concentric exercise bout followed by an eccentric exercise bout one week later. Serum human growth hormone (hGH), creatine kinase (CK), and lactate were measured before, immediately and up to 32 h after both exercise bouts. Higher lactate values were observed immediately, 5 and 10 min after the concentric bout (70%, 119%, and 142%, respectively, p < 0.05) than the eccentric bout. There was a CK main time effect at 8 and 32 h after the exercise bouts compared to baseline values (p < 0.002). However, peak serum CK effect size was higher after the concentric than the eccentric exercise bout, 1.3 and 0.9, respectively. hGH increased after both exercise bouts, however it reached significance only at immediately (207%), 5 min (256%), 10 min (276%), 20 min (300%), and 40 min (168%) after the concentric exercise bout (p < 0.05). Our findings suggest that a previous concentric exercise bout may blunt the anabolic response expected after an eccentric exercise bout.

Time course of strength and power recovery after resistance training with different movement velocities

Ide, BN, Leme, TCF, Lopes, CR, Moreira, A, Dechechi, CJ, Sarraipa, MF, da Mota, GR, Brenzikofer, R, and Macedo, DV. Time course of strength and power recovery after resistance training with different movement velocities. J Strength Cond Res 25(7): 2025-2033, 2011-The purpose of this study was to evaluate the time course of strength and power recovery after a single bout of strength training designed with fast and slow contraction velocities. Nineteen male subjects were randomly divided into 2 groups: the slow-velocity contraction (SV) group and the fast velocity contraction (FV) group. Resistance training protocols consisted of 5 sets of 12 repetition maximum (5 x 12RM) with 50 seconds of rest between sets and 2 minutes between exercises. Contraction velocity was controlled by the execution time for each repetition (SV-6 seconds to complete concentric and eccentric phases and for FV-1.5 seconds). Leg Press 45 degrees 1RM (LP 1RM), horizontal countermovement jump (HCMJ), and right thigh circumference (TC) were accessed in 6 distinct moments: base (1 week before exercise), 0 (immediately after exercises), 24, 48, 72, and 96 hours after exercise protocol. The SV and FV presented significant LP 1RM decrements at 0, and these were still evident 24-48 hours postexercise. The magnitude of decline was significantly (p<0.05) higher for FV. The SV and FV presented significant HCMJ decrements at 0, but only for FV were these still evident 24-72 hours postexercise. The SV and FV presented significant TC increments at 0, and these were still evident 24-48 hours postexercise for SV but for FV it continued up to 96 hours. The magnitude of increase was significantly (p<0.05) higher for FV. In conclusion, the fast contraction velocity protocol resulted in greater decreases in LP 1RM and HCMJ performance, when compared with slow velocity. The results lead us to interpret that this variable may exert direct influence on acute muscle strength and power generation capacity.

Altered left ventricular diastolic function in subjects with spinal cord injury

Study design: This is cross-sectional study. Objectives: The aim of this study is to investigate the cardiac structure and function of subjects with spinal cord injury (SCI) and the impact of metabolic, hemodynamic and inflammatory factors on these parameters. Setting: Sao Paulo, Brazil. Methods: Sixty-five nondiabetic, nonhypertensive, sedentary, nonsmoker men (34 with SCI and 31 healthy subjects) were evaluated by medical history, anthropometry, laboratory tests, analysis of hemodynamic and inflammatory parameters and echocardiography. Results: Subjects with SCI had lower systolic blood pressure and higher levels of C-reactive protein and tumor necrosis factor receptors than the healthy ones. Echocardiography data showed that the SCI group presented similar left ventricular (LV) structural and systolic parameters, but lower initial diastolic velocity (Em) (9.2 +/- 0.5 vs 12.3 +/- 0.5 cm s(-1); P<0.001) and higher peak early inflow velocity (E)/Em ratio (7.7 +/- 0.5 vs 6.1 +/- 0.3; P = 0.009) compared with the able-bodied group, even after adjustment for systolic blood pressure and C-reactive protein levels. Furthermore, injured subjects with E/Em >8 had lower peak spectral longitudinal contraction (Sm) (9.0 +/- 0.7 vs 11.6 +/- 0.4cm s(-1); P<0.001) and cardiac output (4.2 +/- 0.2 vs 5.0 +/- 0.21 min(-1); P = 0.029), as well as higher relative wall thickness (0.38 +/- 0.01 vs 0.35 +/- 0.01; P = 0.005), than individuals with SCI with E/Em<8, but similar age, body mass index, blood pressure, injury level, metabolic parameters and inflammatory marker levels. Conclusion: Subjects with SCI presented impaired LV diastolic function in comparison with able-bodied ones. Moreover, worse LV diastolic function was associated with a pattern of LV concentric remodeling and subclinical decreases in systolic function among injured subjects. Overall, these findings might contribute to explain the increased cardiovascular risk reported for individuals with SCI. Spinal Cord (2011) 49, 65-69; doi: 10.1038/sc.2010.88; published online 27 July 2010

New prediction methods for CO2 evaporation inside tubes: Part II - An updated general flow boiling heat transfer model based on flow patterns

Corresponding to the updated flow pattern map presented in Part I of this study, an updated general flow pattern based flow boiling heat transfer model was developed for CO2 using the Cheng-Ribatski-Wojtan-Thome [L. Cheng, G. Ribatski, L. Wojtan, J.R. Thome, New flow boiling heat transfer model and flow pattern map for carbon dioxide evaporating inside horizontal tubes, Int. J. Heat Mass Transfer 49 (2006) 4082-4094; L. Cheng, G. Ribatski, L. Wojtan, J.R. Thome, Erratum to: ""New flow boiling heat transfer model and flow pattern map for carbon dioxide evaporating inside tubes"" [Heat Mass Transfer 49 (21-22) (2006) 4082-4094], Int. J. Heat Mass Transfer 50 (2007) 391] flow boiling heat transfer model as the starting basis. The flow boiling heat transfer correlation in the dryout region was updated. In addition, a new mist flow heat transfer correlation for CO2 was developed based on the CO2 data and a heat transfer method for bubbly flow was proposed for completeness sake. The updated general flow boiling heat transfer model for CO2 covers all flow regimes and is applicable to a wider range of conditions for horizontal tubes: tube diameters from 0.6 to 10 mm, mass velocities from 50 to 1500 kg/m(2) s, heat fluxes from 1.8 to 46 kW/m(2) and saturation temperatures from -28 to 25 degrees C (reduced pressures from 0.21 to 0.87). The updated general flow boiling heat transfer model was compared to a new experimental database which contains 1124 data points (790 more than that in the previous model [Cheng et al., 2006, 2007]) in this study. Good agreement between the predicted and experimental data was found in general with 71.4% of the entire database and 83.2% of the database without the dryout and mist flow data predicted within +/-30%. However, the predictions for the dryout and mist flow regions were less satisfactory due to the limited number of data points, the higher inaccuracy in such data, scatter in some data sets ranging up to 40%, significant discrepancies from one experimental study to another and the difficulties associated with predicting the inception and completion of dryout around the perimeter of the horizontal tubes. (C) 2007 Elsevier Ltd. All rights reserved.

Subclinical Regional Left Ventricular Dysfunction in Obese Patients With and Without Hypertension or Hypertrophy

We investigated the impact of obesity on the abnormalities of systolic and diastolic regional left ventricular (LV) function in patients with or without hypertension or hypertrophy, and without heart failure. We studied 120 individuals divided into 6 groups of 20 patients (42 +/- 6 years, 60 females) using standard and pulsed-wave tissue Doppler imaging (TDI) echocardiography, and heterogeneity index (HI): nonobese (I: no hypertension, no hypertrophy, control group; II: hypertension, no hypertrophy; III: hypertension and hypertrophy) and obese (IV: no hypertension, no hypertrophy; V: hypertension, no hypertrophy; VI: hypertension and hypertrophy). The criterion for obesity was BMI >= 30 kg/m(2), for hypertension was blood pressure >= 140/90 mm Hg, for hypertrophy in nonobese was LV mass/body surface area (BSA) >134 g/m(2) (men) and >110 mg/m(2) (women), and in obese was LV mass/height((2.7)) >50 (men) and >40 (women). Obese groups had normal LV ejection fraction compared with nonobese groups, but decreased longitudinal and radial systolic myocardial peak velocities (S`), and early diastolic myocardial peak velocity (E`). Also, a great variability of E` and late diastolic myocardial peak velocity (A`) from the longitudinal basal region was observed in obese groups (E` basal nonobese: 11 +/- 7 vs. obese 19 +/- 11, P < 0.001, A` basal nonobese: 7 +/- 4 vs. obese 11 +/- 7, P < 0.001). Our findings were more evident when comparing groups IV with V and VI, with the latter having concentric hypertrophy and obvious segmental systolic and diastolic dysfunctions. Subclinical myocardial alterations and increased variability of the velocities were observed in obese groups, especially with hypertension and hypertrophy, reflecting impaired regional LV relaxation, segmental atrial, and systolic dysfunctions.