Management strategies to minimize the use of synthetic chemical acaricides in the control of the cattle tick Rhipicephalus (Boophilus) microplus (Canestrini, 1888) in an area highly favourable for its development in Argentina.

The aim of this work was to test the efficacy of winter-spring control strategies against Rhipicephalus (Boophilus) microplus (Canestrini, 1888) (Ixodida: Ixodidae) in an area highly favourable for its development in Argentina. Control schemes using three or four annual applications of synthetic acaricides were evaluated. Furthermore, the dynamics of the non-parasitic phases of R. microplus were analysed to provide a framework for the application of pasture spelling as a tool for tick control. The treatment schemes provided appropriate levels of efficacy against R. microplus and also prevented the occurrence of the major peak in abundance of this tick in autumn. A significant overall effect against R. microplus can be achieved when the control strategies tested in this study are applied within the area most ecologically favourable for this tick in Argentina. Analysis of the dynamics of the non-parasitic phase of R. microplus indicates that the spelling period required to achieve a significant reduction of larvae in pastures fluctuates between 12 and 17 weeks if spelling is initiated in spring or early summer, but between 20 and 28 weeks if spelling is started in late summer, autumn or winter.

Surface of Half-Neutralized Diamine Triflate Ionic Liquids. A Molecular Dynamics Study of Structure, Thermodynamics, and Kinetics of Water Absorption and Evaporation.

Surface properties of room temperature ionic liquids (RTILs) consisting of half neutralized diamine cations (H2N-(CH2)n-NH3+, n = 2, 4) and triflate anions have been investigated by molecular dynamics simulations, based on an empirical atomistic force field. Planar slabs periodically repeated in 2D have been considered, and the temperature range 260 ≤ T ≤ 360 K has been covered, extending from below the melting and glass point to the equilibrium liquid range of the diamine compounds under investigation. Addition of water at 1% weight concentration allowed us to investigate the kinetics of water absorption through the RTIL surface, and to characterize the structural and dynamical properties of subsurface water. Animations of the simulation trajectory highlight the quick absorption of water molecules, progressing downhill in free energy and taking place without apparent intermediate kinetic stages. To verify and quantify these observations, a variant of the umbrella sampling algorithm has been applied to compute the variation of excess free energy upon displacing a water molecule along the normal to the surface, from the center of the slab to the vapor phase. The results provide a comprehensive picture of the thermodynamic properties underlying the kinetics of water absorption and evaporation through the surface, and they also provide the ratio of the equilibrium density of water in the vapor and liquid phase at the average concentration considered by simulations. A variety of properties such as the surface energy, the 90-10% width of the profile, the layering of different species at the interface, and the electrostatic double layer at the surface are computed and discussed, focusing on the effect of water contamination on all of them.

The glass transition and the distribution of voids in room-temperature ionic liquids: a molecular dynamics study.

The glass transition in prototypical room temperature ionic liquids has been investigated by molecular dynamics simulations based on an Amber-like empirical force field. Samples of [C(4)mim][PF(6)], [C(4)mim][Tf(2)N], and [C(3)mim][Tf(2)N] have been quenched from the liquid phase at T = 500 to a glassy state at T ∼ 0 K in discontinuous steps of 20 K every 1.2 ns. The glass temperature estimated by simulation (T(g) = 209 K for [C(4)mim][PF(6)], T(g) = 204 K for [C(4)mim][Tf(2)N], and T(g) = 196 K for [C(3)mim][Tf(2)N]) agrees semi-quantitatively with the experimental values (T(g) = 193÷196 K for [C(4)mim][PF(6)], T(g) = 186÷189 K for [C(4)mim][Tf(2)N], and T(g) = 183 K for [C(3)mim][Tf(2)N]). A model electron density is introduced to identify voids in the system. The temperature dependence of the size distribution of voids provided by simulation reproduce well the experimental results of positron annihilation lifetime spectroscopy reported in G. Dlubek, Y. Yu, R. Krause-Rehberg, W. Beichel, S. Bulut, N. Pogodina, I. Krossing, and Ch. Friedrich, J. Chem. Phys. 133, 124502 (2010), with only one free parameter needed to fit the experimental data.

A novel flow injection chemiluminescence determination of Cr(VI) with Dichlorotris(1,10-phenanthroline)ruthenium(II).

A selective novel reverse flow injection system with chemiluminescence detection (rFI-CL) for the determination of Cr(VI) in presence of Cr(III) with Dichlorotris (1,10-phenanthroline)ruthenium(II), (Ru(phen)(3)Cl(2)), is described in this work. This new method is based on the oxidation capacity of Cr(VI) in H(2)SO(4) media. First, the Ruthenium(II) complex is oxidized to Ruthenium(III) complex by Cr(VI) and afterwards it is reduced to the excited state of the Ruthenium(II) complex by a sodium oxalate solution, emitting light inside the detector. The intensity of chemiluminescence (CL) is proportional to the concentration of Cr(VI) and, under optimum conditions, it can be determined over the range of 3-300 µg L(-1) with a detection limit of 0.9 µg L(-1). The RSD was 8.4% and 1.5% at 5 and 50 µg L(-1), respectively. For the rFI-CL method various analytical parameters were optimized: flow rate (1 mL min(-1)), H(2)SO(4) carrier concentration (20% w/V), Ru(phen)(3)Cl(2) concentration (5mM) and sodium oxalate concentration (0.1M). The effect of Cr(III), Fe(III), Al(III), Cd(II), Zn(II), Hg(II), Pb(II), Ca(II) and Mg(II), was studied. The method is highly sensitive and selective, allowing a fast, on-line determination of Cr(VI) in the presence of Cr(III). Finally, the method was tested in four different water samples (tap, reservoir, well and mineral), with good recovery percentage.

Diabetes and minority populations. Focus on Mexican Americans.

Hispanic American people in the United States represent a diverse group by origin, with Mexican Americans comprising the largest and fastest growing segment of this minority population. Whereas few studies have been undertaken to explore diabetes in other Hispanic American groups, several population-based studies have yielded outcomes reflecting significant prevalence and incidence of type II NIDDM among Mexican American people. These rates underscore the need for increasing attention toward understanding dimensions of the population that may effect positive health outcomes. Such is the role of cultural nursing as it relates to diabetes care and education of this population. Cultural nursing embodies a holistic approach to care with focus on assessment of cultural dimensions and attributes as they pertain to the individual with diabetes. Although cultural attributes may vary by ethnic origin, person, and region of the country, the diabetes nurse educators' appreciation of the cultural domain of Hispanicism best provides the patient with the opportunity to effect enactment of necessary diabetes self-care behaviors.

Re-examining repeated testing and teacher effects in a remedial mathematics course.

This study examined the impact of repeated testing and teachers' effects on student achievement in a remedial mathematics course. A 2 x 2 completely randomised factorial design was used, with final examination performance the dependent variable and testing attempts and the teacher factor the independent variables. The study found no main effects for teacher but a main effect for testing attempts and a teacher-factor/testing-attempt interaction. Post hoc findings qualified a direct interpretation of the main effect. The implications for further research and application are discussed, giving special attention to teacher effects, the needs of remedial mathematics instruction, and the claims of mastery-learning pedagogies.

Impact of prospective payment on the role of the diabetes educator.

This paper reports the results of a national survey undertaken to explore the impact of prospective payment on the role of the diabetes educator and on diabetes education. Responses were received from 903 individuals--756 diabetes educators and 147 hospital administrators. Study results indicate a need for diabetes educators to more aggressively shape their role and promote the provision of their services to better assure adequate education for those individuals diagnosed with diabetes.