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Copyright of Contaduría y Administración is the property of Facultad de Contaduria y Administracion-Universidad Nacional Autonoma de Mexico and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Contaduría y Administración is the property of Facultad de Contaduria y Administracion-Universidad Nacional Autonoma de Mexico and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

From the beginning of the 16 until the end of the 19 century the most widely used mirrors consisted of a pane of glass backed with a reflecting layer of tin-mercury amalgam. They were made by sliding the glass pane over a tin foil covered with liquid mercury. After removal of the superfluous mercury, tin amalgam formed slowly at ambient temperature and yielded a reflecting layer adhering to the surface of the glass. Such mirrors often deteriorate in the course of time by oxidation of the tin in the amalgam to stannous or stannic oxide. Sn Mössbauer spectroscopy, scanning electron microscopy, micro-XRF and X-ray diffraction have been used to study this deterioration process. The studied specimens were a modern mirror made for the reconstruction of the Green Vault in Dresden in the early 2000s, two rather well preserved German mirrors from the 17 and 19 centuries and several strongly deteriorated specimens of Baroque mirrors from the south of Spain. The modern mirror consists mainly of a SnHg amalgam with only 2 % of SnO. The older German mirrors showed more pronounced oxidation, containing 12 and 15 % of SnO, which did not noticeably impair their reflectivity. In the samples from the Spanish mirrors at best a few percent of metallic phase was left. The majority of the tin had oxidised to SnO, but between 8 and 20 % of the tin was present as SnO. X-ray diffraction yielded similar results and micro-XRF mapping using synchrotron radiation for excitation gave information on the distribution of Sn and Hg in the reflecting layer of the mirrors. [ABSTRACT FROM AUTHOR]

Salmonella infections are a leading cause of bacterial foodborne illness in the U.S.A. and the European Union Antimicrobial therapy is often administered to treat the infection, but increasingly isolates are being detected that demonstrate resistance to multiple antibiotics. Salmonella enterica contains two virulence-related T3SS (type III secretion systems): one promotes invasion of the intestine and the other one mediates systemic disease. Both of them secrete the SlrP protein acting as E3 ubiquitin ligase in human host cells where it targets Trx1 (thioredoxin-1). SlrP belongs to the NEL family of bacterial E3 ubiquitin ligases that have been observed in two distinct autoinhibitory conformations. We solved the 3D structure of the SlrP-Trx1 complex and determined the Trx1 ubiquitination site. The description of the substrate-binding mode sheds light on the first step of the activation mechanism of SlrP. Comparison with the available structural data of other NEL effectors allowed us to gain new insights into their autoinhibitory mechanism. We propose a molecular mechanism for the regulation of SlrP in which structural constraints sequestrating the NEL domain would be sequentially released. This work thus constitutes a new milestone in the understanding of how these T3SS effectors influence pathogen virulence. It also provides the fundamental basis for future development of new antimicrobials. [ABSTRACT FROM AUTHOR]

We report experimental demonstrations of contact-mode nano-electromechanical switches obtained using a capacitor module based on metal-insulator-metal configuration of a standard commercial complementary metal oxide semiconductor technology. The developed 2 terminals Titanium Nitride switches operate at low voltages (~10 V) thanks to its small gap (27nm), showing an excellent ION/IOFF ratio (104) and abrupt behavior (5mV/decade, one decade of current change is achieved with a 5mV voltage variation). A switch configuration is also presented where using two electrodes three different contact mode states can be obtained, adding functionalities to mechanical switches configurations. [ABSTRACT FROM AUTHOR]

Background: The use of plasma rich in growth factors (PRGF) has been proposed to improve the healing of Achilles tendon injuries, but there is debate about the effectiveness of this therapy. The objective of the present study was to evaluate the histological effects of PRGF, which is a type of leukocyte-poor platelet-rich plasma, on tendon healing. Methods: The Achilles tendons of twenty-eight sheep were divided surgically. The animals were randomly divided into four groups of seven animals each. The repaired tendons in two groups received an infiltration of PRGF intraoperatively and every week for the following three weeks under ultrasound guidance. The tendons in the other two groups received injections with saline solution. The animals in one PRGF group and one saline solution group were killed at four weeks, and the animals in the remaining two groups were killed at eight weeks. The Achilles tendons were examined histologically, and the morphometry of fibroblast nuclei was calculated. Results: The fibroblast nuclei of the PRGF-treated tendons were more elongated and more parallel to the tendon axis than the fibroblast nuclei of the tendons in the saline solution group at eight weeks. PRGF-treated tendons showed more packed and better oriented collagen bundles at both four and eight weeks. In addition to increased maturation of the collagen structure, fibroblast density was significantly lower in PRGF-infiltrated tendons. PRGF-treated tendons exhibited faster vascular regression than tendons in the control groups, as demonstrated by a lower vascular density at eight weeks. Conclusions: PRGF was associated with histological changes consistent with an accelerated early healing process in repaired Achilles tendons in sheep after experimental surgical disruption. PRGF-treated tendons showed improvements in the morphometric features of fibroblast nuclei, suggesting a more advanced stage of healing. At eight weeks, histological examination revealed more mature organization of collagen bundles, lower vascular densities, and decreased fibroblast densities in PRGF-treated tendons than in tendons infiltrated with saline solution. These findings were consistent with a more advanced stage of the healing process. Clinical Implications: Based on the findings in this animal model, PRGF infiltration may improve the early healing process of surgically repaired Achilles tendons. [ABSTRACT FROM AUTHOR]

The article presents a study on testicular and paratesticular tumors in children and adolescents less than 18 years of age. It states that the study shows 11 primary testicular tumors and 4 paratesticular tumors or rhabdomyosarcomas in a series of 15 cases in patients, with 60% being germinal tumors and the rest non-germinal. It is inferred that testicular and paratesticular tumors in prepubertal children reveal evolutional and therapeutical characteristics well differentiated from adult cases.

Fast wave injection is employed on the DIII-D tokamak as a current drive and electron heating method. Bursts of energetic ions with energy E0 > 20 keV are observed immediately following fast wave injection in experiments featuring the 8th ion cyclotron harmonic near the antenna. Using the energy and pitch angle of the energetic ion burst as measured by a fast-ion loss detector, it is possible to trace the origin of these ions to a particular antenna. The ion trajectories exist entirely within the scrape-off layer. These observations are consistent with the presence of parametric decay instabilities near the antenna strap. It is suggested that the phase space capabilities of the loss detector diagnostic can improve studies of wave injection coupling and efficiency in tokamaks by directly measuring the effects of parametric decay thresholds. [ABSTRACT FROM AUTHOR]

With incident fluences of ≈ 1012 atoms/cm² aluminium samples have been plasma immersion ion implanted with either pure nitrogen or argon/nitrogen mixtures at temperatures around 450°C. X-ray diffraction studies have validated the formation of the cubic phase of AlN, in samples treated with both the gas mixtures and pure nitrogen. Likewise, the presence of the hexagonal phase of AlN has been detected when either pure nitrogen or a 70%N/30%Ar mixture have been used. The signature peak of AlN has also been confirmed by the Raman spectroscopy. The maximal microhardness values were found in samples treated with the mixture. The maximal roughness was achieved with the equal part mixture in all cases, although increasing with the implantation pulse width up to a 300 nm peak at 150 μs. The latter critical value remains invariant under the pure nitrogen plasma treatment, provided that implantation periods in the order of 4.5 h are carried out. [ABSTRACT FROM AUTHOR]

Agent-systems can bring important benefits especially in applications scenarios where highly distributed, autonomous, intelligence, self-organizing, and robust systems are required. Furthermore, the high levels of autonomy and self-organizations of agent systems provide excellent support for developments of systems in which dependability is essential. Both Ubiquitous Computing and Ambient Intelligence scenarios belong in this category. Unfortunately, the lack of appropriate security mechanisms, both their enforcement and usability, is hindering the application of this paradigm in real-world applications. Security issues play an important role in the development of multiagent systems and are considered to be one of the main issues to solve before agent technology is ready to be widely used outside the research community. In this paper, we present a software based solution for the protection of multiagent systems concentrating on the cooperative agents model and the protected computing approach. [ABSTRACT FROM AUTHOR]

The time decay of the relative initial magnetic permeability after sample demagnetization has been measured in the temperature range 80K < T < 420K in series of samples with initial composition BaO·nFe2O3 (n = 5.7, 6 and 6.3), i.e. the stoichiometric M-type barium ferrite and compositions with excess and defect of iron. These samples have been sintered under different conditions of temperature and partial oxygen pressure. The results have been represented by means of isochronal curves. We have observed that the behaviour changes drastically with the sintering atmosphere, and the results with less iron are qualitatively different from the others when sintering in air. The underlying mechanisms responsible for the relaxation phenomena observed are pointed out in terms of the formation of different hexagonal phases. [ABSTRACT FROM AUTHOR]

It is known that there is not a two dimensional linear space in RR every non-zero element of which is an injective function. Here, we generalize this result to arbitrarily large dimensions. We also study the convolution of nondifferentiable functions which gives, as a result, a differentiable function. In this latter case, we are able to showthe existence of linear spaces of the largest possible dimension formed by functions enjoying the previous property. By doing this we provide both positive and negative results to the recent field of lineability. Some open questions are also provided. [ABSTRACT FROM AUTHOR]

Background: The prevalence of inflammation is high among patients with chronic renal failure but the reason of inflammation is unclear. We test the hypothesis that inflammation in chronic renal failure could be the consequence of an increased left-ventricular wall tension related to ventricular dysfunction, hypervolemia or both. Methods: For assessing left-ventricular filling pressure, plasma level of N-terminal pro-B-type natriuretic peptide (N-BNP) was used, as B-type natriuretic peptide is secreted from the cardiac ventricles in response to increased wall tension. N-BNP levels and C-reactive protein (CRP) were measured on the same day in 75 pre-dialysis patients. A previous history of cardiomiopathy with systolic dysfunction was present in 27 (36%) of them. Results: The levels of N-BNP were not normally distributed (mean: 2,589 ± 4,514 pg/ml; median: 789 pg/ml). The distribution of CRP levels was also not normal (mean: 15 ± 27 mg/l; median: 5 mg/l). Both parameters correlated significantly (r: 0.41; p < 0.005). N-BNP was higher (p < 0.001) in patients with known ventricular dysfunction. Excluding these patients, the correlation between N-BNP and CRP was stronger (r: 0.88; p < 0.001). Univariate analysis in these patients without known cardiomyopathy showed that N-BNP levels also correlated with systolic and diastolic blood pressure (r: 0.54; p < 0.005) and inversely with creatinine clearance (r: –0.43; p < 0.01), serum albumin (r: 0.6; p < 0.001) and hemoglobin levels (r: 0.37; p < 0.05). CRP levels correlated significantly (p < 0.01) with the same parameters as N-BNP in univariate analysis. However, in multiple stepwise regression analysis in which CRP was the dependent variable, only the association with N-BNP remained significant (r: 0.87; p < 0.001). Conclusions: Our results suggest a link between left-ventricular filling pressure and inflammation in patients with advanced renal insufficiency. The importance of strict volume control in these patients, in order to reduce left-ventricular pressure and therefore inflammation, should be considered. Copyright © 2004 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]