Piezoelectric nanoelectromechanical resonators based on aluminum nitride thin films

We demonstrate piezoelectrically actuated, electrically tunable nanomechanical resonators based on multilayers containing a 100-nm-thin aluminum nitride (AlN) layer. Efficient piezoelectric actuation of very high frequency fundamental flexural modes up to ~80 MHz is demonstrated at room temperature. Thermomechanical fluctuations of AlN cantilevers measured by optical interferometry enable calibration of the transduction responsivity and displacement sensitivities of the resonators. Measurements and analyses show that the 100 nm AlN layer employed has an excellent piezoelectric coefficient, d_(31)=2.4 pm/V. Doubly clamped AlN beams exhibit significant frequency tuning behavior with applied dc voltage

Sympathovagal balance and 1-h postload plasma glucose in normoglucose tolerant hypertensive patients.

AIMS: Normoglucose tolerant (NGT) subjects with a 1-h postload plasma glucose (PLPG) value ≥155 mg/dL have an increased risk of type-2 diabetes and subclinical organ damage. Heart rate variability (HRV) reflects cardiac autonomic balance, frequently impaired in course of diabetes. At this time, no data support the association between 1-h PLPG and HRV; thus, we investigated the possible association between 1-h PLPG and HRV. METHODS: We enrolled 92 never-treated hypertensive subjects (56 women, 36 men), aged 55 ± 9.8 years. During OGTT, the patients underwent electrocardiographic recordings to evaluate HRV in the time domain (SDNN). Insulin sensitivity was assessed by Matsuda index. RESULTS: Among participants, 56 were NGT, 20 had impaired glucose tolerance (IGT), and 16 had type-2 diabetes. According to the 1-h PLPG cutoff point of 155 mg/dL, we divided NGT subjects into: NGT < 155 (n = 38) and NGT ≥ 155 (n = 18). Glucose tolerance status was associated with a significant (P < 0.0001) increase in PLPG and insulin and the reduction in Matsuda index. In all groups, the SDNN values significantly (P < 0.0001) decreased during the first hour of OGTT. A complete recovery in NGT groups was observed at the end of the second hour; in IGT and type-2 diabetes, SDNN remained significantly lower with respect to baseline values. At multiple regression analysis, Matsuda index resulted in the only determinant of SDNN modification, explaining the 12.3 % of its variability. CONCLUSIONS: Our data demonstrate that during OGTT, sympathovagal balance is acutely affected by both glucose and insulin modifications. Particularly, NGT ≥ 155 subjects behave in the same way of IGT and type-2 diabetes patients

Pedestrians moving in dark: Balancing measures and playing games on lattices

We present two conceptually new modeling approaches aimed at describing the motion of pedestrians in obscured corridors: * a Becker-D\"{o}ring-type dynamics * a probabilistic cellular automaton model. In both models the group formation is affected by a threshold. The pedestrians are supposed to have very limited knowledge about their current position and their neighborhood; they can form groups up to a certain size and they can leave them. Their main goal is to find the exit of the corridor. Although being of mathematically different character, the discussion of both models shows that it seems to be a disadvantage for the individual to adhere to larger groups. We illustrate this effect numerically by solving both model systems. Finally we list some of our main open questions and conjectures

Instantaneous shrinking and single point extinction for viscous Hamilton-Jacobi equations with fast diffusion

International audienceFor a large class of non-negative initial data, the solutions to the quasilinear viscous Hamilton-Jacobi equation $\partial_t u-\Delta_p u+|\nabla u|^q=0$ in $(0,\infty)\times\mathbb{R}^N$ are known to vanish identically after a finite time when $2N/(N+1) 0$, the positivity set of $u(t)$ is a bounded subset of $\mathbb{R}^N$ even if $u_0 > 0$ in $\mathbb{R}^N$. This decay condition on $u_0$ is also shown to be optimal by proving that the positivity set of any solution emanating from a positive initial condition decaying at a slower rate as $|x|\to\infty$ is the whole $\mathbb{R}^N$ for all times. The time evolution of the positivity set is also studied: on the one hand, it is included in a fixed ball for all times if it is initially bounded (\emph{localization}). On the other hand, it converges to a single point at the extinction time for a class of radially symmetric initial data, a phenomenon referred to as \emph{single point extinction}. This behavior is in sharp contrast with what happens when $q$ ranges in $[p-1,p/2)$ and $p\in (2N/(N+1),2]$ for which we show \emph{complete extinction}. Instantaneous shrinking and single point extinction take place in particular for the semilinear viscous Hamilton-Jacobi equation when $p=2$ and $q\in (0,1)$ and seem to have remained unnoticed

A degenerate pseudo-parabolic equation with memory

We prove the existence and uniqueness for a degenerate pseudo-parabolic problem with memory. This kind of problem arises in the study of the homogenization of some differential systems involving the Laplace-Beltrami operator and describes the effective behaviour of the electrical conduction in some composite materials

Self-similar extinction for a diffusive Hamilton-Jacobi equation with critical absorption

International audienceThe behavior near the extinction time is identified for non-negative solutions to the diffusive Hamilton-Jacobi equation with critical gradient absorption ∂_t u − ∆_p u + |∇u|^{p−1} = 0 in (0, ∞) × R^N , and fast diffusion 2N/(N + 1) < p < 2. Given a non-negative and radially symmetric initial condition with a non-increasing profile which decays sufficiently fast as |x| → ∞, it is shown that the corresponding solution u to the above equation approaches a uniquely determined separate variable solution of the form U (t, x) = (T_e − t)^{1/(2−p)} f_* (|x|), (t, x) ∈ (0, T_e) × R^N , as t → T_e , where T_e denotes the finite extinction time of u. A cornerstone of the convergence proof is an underlying variational structure of the equation. Also, the selected profile f_* is the unique non-negative solution to a second order ordinary differential equation which decays exponentially at infinity. A complete classification of solutions to this equation is provided, thereby describing all separate variable solutions of the original equation. One important difficulty in the uniqueness proof is that no monotonicity argument seems to be available and it is overcome by the construction of an appropriate Pohozaev functional

Applying the Maternal Near Miss Approach for the Evaluation of Quality of Obstetric Care: A Worked Example from a Multicenter Surveillance Study

Objective. To assess quality of care of women with severe maternal morbidity and to identify associated factors. Method. This is a national multicenter cross-sectional study performing surveillance for severe maternal morbidity, using the World Health Organization criteria. the expected number of maternal deaths was calculated with the maternal severity index (MSI) based on the severity of complication, and the standardized mortality ratio (SMR) for each center was estimated. Analyses on the adequacy of care were performed. Results. 17 hospitals were classified as providing adequate and 10 as nonadequate care. Besides almost twofold increase in maternal mortality ratio, the main factors associated with nonadequate performance were geographic difficulty in accessing health services (P < 0.001), delays related to quality of medical care (P = 0.012), absence of blood derivatives (P = 0.013), difficulties of communication between health services (P = 0.004), and any delay during the whole process (P = 0.039). Conclusions. This is an example of how evaluation of the performance of health services is possible, using a benchmarking tool specific to Obstetrics. in this study the MSI was a useful tool for identifying differences in maternal mortality ratios and factors associated with nonadequate performance of care.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Univ Campinas UNICAMP, Sch Med Sci, Dept Obstet & Gynaecol, BR-13083881 Campinas, SP, BrazilCtr Res Reprod Hlth Campinas Cemicamp, BR-13083888 Campinas, SP, BrazilUniv Fed Amazonas, Manaus, Amazonas, BrazilSch Med Sci, CISAM, Recife, PE, BrazilUniv Fed Ceara, Fortaleza, Ceara, BrazilUniv Fed Bahia, Salvador, BA, BrazilHosp Geral Cesar Cals, Fortaleza, Ceara, BrazilHosp Geral Fortaleza, Fortaleza, Ceara, BrazilMaternidade Odete Valadares, Belo Horizonte, MG, BrazilHosp Materno Infantil, Goiania, Go, BrazilInst Materno Infantil Pernambuco, Recife, PE, BrazilUniv Fed Pernambuco, Recife, PE, BrazilUniv Fed Campina Grande, Campina Grande, PB, BrazilUniv Fed Maranhao, Sao Luis, MA, BrazilUniv Fed Parana, BR-80060000 Curitiba, Parana, BrazilUniv Fed Paraiba, BR-58059900 Joao Pessoa, Paraiba, BrazilHosp Maternidade Fernando Magalhaes, Rio de Janeiro, RJ, BrazilUniv Fed Rio Grande do Sul, Porto Alegre, RS, BrazilHosp Maternidade Celso Pierro, Campinas, SP, BrazilInst Fernandes Figueira Fiocruz, Rio de Janeiro, RJ, BrazilHosp Israelita Albert Einstein, São Paulo, BrazilUniv State São Paulo, Botucatu, SP, BrazilJundiai Sch Med, Jundiai, SP, BrazilUniv São Paulo, BR-14049 Ribeirao Preto, SP, BrazilSanta Casa Limeira, Limeira, SP, BrazilSanta Casa Sao Carlos, Sao Carlos, SP, BrazilMaternidade Leonor Mendes de Barros, São Paulo, BrazilUniversidade Federal de São Paulo, São Paulo, BrazilUniversidade Federal de São Paulo, São Paulo, BrazilCNPq: 402702/2008-5Web of Scienc

Ingestive Behavior of Beef Cattle Fed Either Protein or Energy Supplements under a Rotational Grazing System

Eight Nellore bullocks were assigned to a Tanzânia grass pasture (Panicum maximum Jacq.) under a rotational grazing system, to evaluate the ingestive behavior under two different grazing residues. Stocking rate intensity was used to reach either 1000 kg DM.ha-1 (R1) or 4000 kg DM.ha-1 (R2) as residual targets. Three grazing days followed by 33 days resting period, composed a 36 day grazing cycle. Each grazing plot supported four animals, in a 4x4 Latin square design, within the following supplementation rates and sources: S1 = no supplement; S2 = 2,0 kg DM.day-1 coarsely ground corn - 8 mm sieve; S3 = 2,0 kg DM.day-1 steam flaked corn (360 g/L) and S4 = 0,7 kg DM.day-1 soybean meal. Grazing behavior measurements were taken every 15 days after 9 a day adaptation period, during two consecutive summer grazing cycles. Animal activities were recorded every 5 minutes during day time and 15 minutes during night time throughout a 24 hour period. Supplementation with S2 decreased (P \u3c 0,05) rumination time under a higher grazing residue (R2). Both grazing and rumination time were increased and led to a decreased resting time (P \u3c 0,05) in R2 animals compared with R1