Organization and seasonal quantification of the intertubular compartment in the bat Molossus molossus (Pallas, 1776) testis

Environmental factors can influence the reproductive rates in bats, and since morphometric information of bats testis is scarce, we aimed to compare the organization and quantification of the intertubular components in the testes of the bat Molossus molossus, collected in different seasons. Testicular histological sections were evaluated using light and electron microscopy. The intertubular compartment occupied an average 10% of the testes, being predominately constituted of Leydig cells (LC). The percentages of the testes occupied by the intertubular compartment and by LC were significantly higher in summer, while the other intertubular components did not vary significantly among the seasons. As suspected under light microscopy, the ultrastructural analysis confirmed the existence of multinucleated LC during winter. The increase in the nuclear percentage of LC in winter seems to have caused the decrease of the cytoplasmatic measurements in that season, as well as in the volume of LC. The highest cytoplasmatic values and volume of LC registered in the spring, summer, and fall can be related to greater activity of this cell in these seasons. The higher investment in intertubular tissue and in LC observed in summer, compared to winter; suggest an increase in the steroidogenic capacity of this bat during summer. The analyses correlating testicular morphometry and abiotic environmental factors in this study confirm the influence of climatic factors on the reproduction of M. molossus. Microsc. Res. Tech., 2013. © 2012 Wiley Periodicals, Inc.     

Computational study of band-crossing reactions

A numerical study of band-crossing reactions is conducted using a quasi-one-dimensional (1-D) computational model that accounts for species bulk advection, electromigration velocities, diffusion, and chemical reaction. The model is used to simulate chemical reactions between two initially distinct sample zones, referred to as "bands," that cross each other due to differences in electromigration velocities. The reaction is described in terms of a single step, reversible mechanism involving two reactants and one product. A parametric study is first conducted of the behavior of the species profiles, and results are interpreted in terms of the Damko/spl uml/hler number and of the ratios of the electromigration velocities of the reactant and product. Computed results are then used to explore the possibility of extracting forward and backward reaction rates based on time resolved observation of integral moments of species concentrations. In particular, it is shown that in the case of fast reactions, robust estimates can be obtained for high forward rates, but that small reverse rates may not be accurately observed.     

A spectrum of TCP-friendly window-based congestion control algorithms

The increasing diversity of Internet application requirements has spurred recent interest in transport protocols with flexible transmission controls. In window-based congestion control schemes, increase rules determine how to probe available bandwidth, whereas decrease rules determine how to back off when losses due to congestion are detected. The control rules are parameterized so as to ensure that the resulting protocol is TCP-friendly in terms of the relationship between throughput and loss rate. This paper presents a comprehensive study of a new spectrum of window-based congestion controls, which are TCP-friendly as well as TCP-compatible under RED. Our controls utilize history information in their control rules, and by doing so, they improve the transient behavior. We demonstrate analytically, and through extensive ns simulations, the steady-state and transient behavior of several instances of this new spectrum.     

Characterisation of Trypanosoma cruzi populations by DNA polymorphism of the cruzipain gene detected by single-stranded DNA conformation polymorphism (SSCP) and direct sequencing

Fifty fresh isolates of Trypanosoma cruzi from Triatoma dimidiata vectors and 31 from patients with Chagas' disease were analysed for DNA polymorphisms within the 432-bp core region of the cruzipain gene which encodes the active site of cathepsin L-like cystein proteinase. The cruzipain gene showed signs of polymorphism consisting of four different DNA sequences in Central and South American isolates of T. cruzi. The PCR fragments of Guatemalan isolates could be divided into three groups, Groups 1, 2 and 3, based on different patterns of single-stranded DNA conformation polymorphism. All of the strains isolated from Brazil, Chile, and Paraguay, except for the CL strain, showed a Group 4 pattern. Two to four isolates from each group were analysed by cloning and sequencing. A silent mutation occurred between Groups 1 and 2, and five nucleotides and two aa substitutions were detected between Groups 1 and 3. The DNA sequence of Group 4 contained five nucleotides and one aa substitution from Group 1. All of the DNA sequences corresponded well with the single-stranded DNA conformation polymorphism. The Group 1 isolates, the majority in the Guatemalan population (70/81, 86.4%), were isolated from both triatomines and humans, but Group 3 were isolated only from humans. Moreover, the Group 2 isolates were detected only in triatomine vectors (9/50; 18%), but never in humans (0/32, P<0.05) suggesting that this group has an independent life-cycle in sylvatic animals and is maintained by reservoir hosts other than humans.     

In vivo semen-associated pH neutralization of cervicovaginal secretions

To determine (1) the relationship between primary hyperparathyroidism with mild hypercalcemia and psychiatric disturbances, bone density, or non-specific symptoms, and (2) the effect of parathyroidectomy on these outcomes, a systematic and critical review of the literature was conducted. Relevant citations were identified using MEDLINE (1966 to August, 1995) and PsycINFO (1967 to August, 1995). Studies were included for the overview if they described patients with mild hypercalcemia (< 12 mg/dl), and if they dealt with at least one of the following outcomes: psychiatric disturbances, bone density, joint pain, constipation, polyuria/nocturia or weight loss. Either a calculated effect size or Z score was used to estimate the effect of the disease or parathyroidectomy on these outcomes. Seven studies met the inclusion criteria for this overview. Two out of three case-control studies on psychiatric symptoms found a significant association between primary hyperparathyroidism with mild hypercalcemia and psychiatric disturbances (effect sizes; 0.17, 1.2 and 1.6). One of the three studies also examined the effect of parathyroidectomy on psychiatric symptoms, and found an effect size of 1.5. All four cross-sectional studies that measured bone mass showed significantly reduced bone density in the forearm and the lumbar spine. The bone loss ranged from 0.9 to 1.4 standard deviation below the age- and sex-adjusted mean value in the forearm, and was 0.5 in the spine. There was no relevant study regarding non-specific symptoms. Among the seven studies, five did not explicitly indicate whether the patients had classical symptoms of either osteitis fibrosa cystica or renal stones. Primary hyperparathyroidism with mild hypercalcemia is associated with psychiatric disturbances and reduced bone density. Nevertheless, further research is needed to determine the symptoms, particularly for a group of patients without either classical bone disease or renal stones. The effects of parathyroidectomy on these outcomes also remain to be determined.     

Correlation analysis between phenolic levels of Brazilian propolis extracts and their antimicrobial and antioxidant activities

Propolis extracts are currently used for the treatment of oronasal infections and as antioxidant agents. Ethanolic commercial Brazilian propolis extracts were assayed for their ability to inhibit the growth of Staphylococcus aureus and also for their ability to scavenge DPPH radicals. These activities were correlated with their total phenolic and flavonoid levels. In one group of extracts there was a strong linear relationship between total phenol contents and the measured activities, while in the other group this relationship was weaker. It was also found that flavonoid levels had a greater influence on the antioxidant activity of these extracts than on their antimicrobial profiles.     

An integrated approach for the configuration of automated manufacturing systems

The paper proposes a new integrated approach for supporting firms in their decisions of dimensioning automated production systems. The problem is closely related to the performance evaluation of the system since discriminating indicators are necessary to rank different alternatives. Traditionally, analytical methods and simulation have been used to evaluate the production system performance, with minor emphasis on the relationships between the tools and their use. Given the complexity of the problem, it is not possible to use only analytical methods that cannot enter deeply in problem details; at the same time the space of potential system configurations is too large to be evaluated by means of detailed tools such as simulation. In the proposed methodology, the problem is decomposed hierarchically into different sub-problems; each one has a different level of detail and a specific performance evaluation tool is used. At each level of the analysis, each system configuration is compared, by means of statistical tests, with the other alternatives with the purpose of discarding unprofitable solutions.     

Externally post-tensioned carbon FRP bar system for deflection control

Externally post-tensioned steel tendons have long been an attractive option for increasing the design loads or correcting strength and serviceability problems in bridge and building structures. More recently, alternative solutions have been developed and implemented that use straight post-tensioned carbon fiber reinforced polymer (CFRP) tendons, ideally enlisting their high-strength to failure, small relaxation, corrosion resistance, and light weight. In this paper, a novel CFRP system for external post-tensioning is presented. The solution consists of unbonded CFRP bars connected to dead- and live-end steel anchors by means of couplers that allow the bar to develop the full tensile strength. Intermediate deviators can be extended vertically to impart additional post-tensioning (PT) force and achieve a profiled bar configuration. The required uplift forces for deflection control of a flexural member are provided by modifying the number, position and extended height of the deviators, similarly to commercially available systems that use steel wire strands. The structural efficiency of such approach in controlling deflection is analyzed and discussed for single-span one-way members on the basis of a parametric study that considers the influence of member geometry, flexural stiffness, boundary conditions, and PT system layout. A design example is also provided.