Analysis of dielectric guides by transverse magnetic field finiteelement penalty method

The main purpose of this paper is to use the finite element method using a penalty function formulation to solve the vector wave equation with transverse H-field formulation together with the boundary operator. We impose continuity conditions on the boundary interfaces for both E _z and H_z components. We apply this technique to obtain the propagation constant for a three-layer ridge structure and a multiple quantum well ridge guide as examples, and a comparison with previously published results shows excellent agreement     

L-cystine-di-beta-naphthylamidase activity in plasma of the snake Bothrops jararaca after chronic challenges of water balance

Plasma protein, osmolality and L-cystine-di-beta-naphthylamidase activity were measured in Bothrops jararaca snakes submitted to normal hydration, water deprivation, water loading, salt loading or argvasotocin injections. Protein and osmolality were similar for male and female snakes in all treatments. Protein content was similar in all treatments, indicating the ability of the animals to maintain fluid balance between the vascular and extravascular compartment under osmotic challenges. Osmolality was increased in water-deprived and salt-loaded and was decreased in water-loaded animals compared with normally hydrated or argvasotocin-injected snakes. Enzymatic activity differed between males and females and was higher in salt-loaded females and in arg-vasotocin-injected females and males than in water-loaded snakes. A positive linear regression between osmolality and L-cystine-di-beta-naphthylamidase was obtained for female snakes (correlation coefficient = 0.6162, P < 0.01). The data show a role of arg-vasotocin in the consistent relationship between water balance and this sex-related aminopeptidase activity.     

Rapid multiexcitation fluorescence spectroscopy system for in vivo tissue diagnosis

We have designed, fabricated, and tested a compact, transportable, excitation-emission spectrofluorimeter with optical-fiber light delivery and collection for use in rapid analysis of tissues in a clinical setting. This system provides up to eleven different excitation wavelengths, permitting collection of all the corresponding emission spectra in approximately 600 ms. It uses a N(2) laser that pumps a sequence of dyes placed in cuvettes on a rotating wheel. A white-light excitation source permits acquisition of the tissue's diffuse reflectance spectrum on each cycle. Return fluorescence and reflected light are dispersed by a small spectrograph and detected by a photodiode-array detector. The system can collect a single-shot spectrum from biological tissue with a signal-to-noise ratio in excess of 50:1.     

Polarization microscopy as a tool for quantitative evaluation of collagen using picrosirius red in different stages of CKD in cats

Chronic kidney disease (CKD) is a relevant disease in feline clinic. The tubulointerstitial damage, with collagen deposition and fibrosis, is an important result of this process. The aim of this study was to quantify and correlate the deposition of collagen and severity of interstitial fibrosis (IF) in the kidney from cats in different stages of CKD. Kidney fragments from 10 adult cats with CKD were analyzed and stained by Masson's trichrome (MT) and Picrosirius red (PSR) for circular polarized microscopy. Random quantitative analysis was performed on MT sections to classify the degree of IF, per field area, with and without circular polarization. Statistics correlations were performed by Spearman's (ρ; p < .05). There was a significant correlation of IF quantification with the area of interstitial collagen deposition by polarized PSR (PSRp) (r = .7939, p = .0098) and nonpolarized PSR (PSRn) (r = .7781, p = .0080). There was a positive correlation of serum creatinine (sCr) at different stages of CKD with PSRp (r = .7939, p = .0098), PSRn (r = .8667, p = .0027) and MT (r = .7818, p = .0117). Correlations between the percentage of quantified area was also positive from PSRp to PSRn (r = .9030, p = .0009) and PSRp to MT (r = .7939, p = .0098). The PSRN was also correlated with MT (r = .9273, p = .0001). The correlation with IF and sCr follows the disease evolution and the quantification of collagen by PSR is an excellent tool for analyzing the disease severity at different stages.     

Peeling Meshed Potatoes

We study variants of the potato peeling problem on meshed (triangulated) polygons. Given a polygon with holes, and a triangular mesh that covers its interior (possibly using additional vertices), we want to find a largest-area connected set of triangles of the mesh that is convex, or has some other shape-related property. In particular, we consider (i) convexity, (ii) monotonicity, (iii) bounded backturn, and (iv) bounded total turning angle. The first three problems are solved in polynomial time, whereas the fourth problem is shown to be NP-hard.     

The bug report duplication problem: an exploratory study

Duplicate bug report entries in bug trackers have a negative impact on software maintenance and evolution. This is due, among other factors, to the increased time spent on report analysis and validation, which in some cases takes over 20 min. Therefore, a considerable amount of time is lost in duplicate bug report analysis. In order to understand the possible factors that cause bug report duplication and its impact on software development, this paper presents an exploratory study in which bug tracking data from private and open source projects were analyzed. The results show, for example, that all projects we investigated had duplicate bug reports and a considerable amount of time was wasted by this duplication. Furthermore, features such as project lifetime, staff size, and the number of bug reports do not seem to be significant factors for duplication, while others, such as the submitters’ profile and the number of submitters, do seem to influence the bug report duplication.     

Measurement of the friction of paper by the strip-on-drum method

The friction between paper surfaces has been studied in a strip-on-drum geometry, under quasistatic and slow sliding conditions. The method provides a better simulation of some practical applications than other more widely used tests. The mechanics of the test have been analysed for two cases: with constant coefficient of friction; and with the friction force related to normal pressure by a power law. The behaviour of four different types of paper was examined. In all cases, the coefficient of friction of the sample fell with repeated sliding; this was associated with progressive damage to the paper surface, and has implications for the design of standard friction test methods for paper. The coefficient of friction (COF) also depended significantly on the contact pressure, in a way that can be correlated with the relative compressibilities of the different paper structures. The pressure dependence of friction, at low pressures, was accurately modelled by a power-law relationship.     

Mercury and selenium concentrations in hair samples of women in fertile age from Amazon riverside communities

The aim of the present study was to evaluate mercury and selenium concentrations in hair samples of reproductive age women from riverside communities of the Tapajós River basin. We studied 19 pregnant and 21 non-pregnant women, 13 to 45 years old, living in the region for at least 2 years, and having a diet rich in fish. The analysis of Se and total Hg were performed in the Instituto de Pesquisas Energéticas e Nucleares (IPEN, S?o Paulo, Brazil) by using a Varian AA220-FS atomic absorption spectrometer with a flow injection system. There were no differences between the two groups - pregnant and non-pregnant -- concerning age (23.80 +/- 6.92 and 26.60 +/- 9.60 years old, respectively) and residential time (20.21 +/- 8.30 and 22.20 +/- 10.90 years, respectively). The geometric means and ranges for total Hg concentration were similar (p > 0.05): 8.25 microg/g (1.51-19.43) in pregnant and 9.39 microg/g (5.25-21.00) in non-pregnant women, respectively. Total Hg concentrations were also similar in different gestational stages. However, there was a significant difference between the two groups (p < 0.05, Student t test) in relation to Se concentration: 0.61 microg/g (0.40-2.33) in pregnant and 2.46 microg/g (0.92-5.74) in non-pregnant women, respectively. We concluded that Hg exposure levels in reproductive age women were only slightly higher than a provisional tolerable weekly intake of MeHg would provide, that Hg concentration in maternal hair samples was independent of gestational age, and that low Se concentration in pregnant women indicates high mineral consumption by fetal organism to satisfy their metabolic requirements raised during pregnancy, including as a protective mechanism for Hg cytotoxic effects.