COMPARATIVE STUDY OF DIFFERENT STRETCHING PROTOCOLS ON FLEXIBILITY AND PASSIVE RESISTANCE OF HAMSTRINGS

This investigation determined the effects of different static stretching protocols on flexibility and passive resistance of the hamstrings. Forty healthy young adults were randomly assigned into one of four groups. The two training groups underwent static stretch training by a four-week and an eight-week protocol, respectively. The other two were control groups. A significant increase in hamstring flexibility was found in both of the two training groups. No difference was found in the amount of range of motion (ROM) gained between the two training groups. An increase in passive resistance was only found in the four-week training group. Both protocols are effective in terms of improving hamstring flexibility. However, if injury is reduced when there is relatively lower passive resistance at end-of-range then the eight week regimen would be recommended

Glycaemic control, lipid profile, blood pressure and body weight status among diabetics in rural Malaysia.

Diabetes is associated with a high risk of cardiovascular disease. The management of blood glucose, dyslipidaemia and other modifiable risk factor, is a key element in the multifactorial approach to prevent complications of type 2 diabetes. Materials and Methods: A cross sectional study was conducted to determine the level of glycaemic control, lipid profile, blood pressure and body weight status among type 2 diabetics in rural Malaysia. A total of 237 diabetic subjects participated in this study. Physical examination was carried out, including measurements of height, weight, waist and hip circumferences, and systolic and diastolic blood pressure. Fasting venous blood samples were collected to determine the glucose level and lipid profile. Results: About 70% of the subjects had a high body mass index (BMI), equal to or above 25 kg/ m2. More than 60% of the subjects had systolic blood pressure ≥ 140 mmHg and/or diastolic ≥ 90 mmHg. Mean fasting blood glucose was 9.84±4.54 mmol/L. Mean total cholesterol was 5.18±1.35 mmol/L. High density lipoprotein cholesterol (HDLC) and triglyceride (TG) and glucose levels were higher in male than in female, but not statistically significant (p>0.05). However, low density lipoprotein cholesterol (LDLC) was higher in females than males (p<0.05). Mean HDLC was below 1.0 mmol/L in all subjects. Conclusion: Glycaemic control, lipid profile, blood pressure and body weight status were not satisfactory and may increase the risk of microvascular and macrovascular complications among these subjects. Appropriate intervention programs should be implemented for better diabetes control among rural subjects

Wintertime CO2 Emission from Soils of Northeastern Siberia

The emission of C02 from northeastern Siberian soil was estimated for the period December 1989 to February 1990. Concentrations of air CO2 near the ground and 1 m above the snow cover were measured by an infrared gas analyzer. Fluxes of CO2 across the snow cover were calculated from the differences of these two values and the predetermined CO2 transfer coefficients at various flux rates through a layer of snow. Temperature and moisture content of the soil profiles were also observed simultaneously. The average transfer coefficient of CO2 for packed snow measured in the winter of 1989/90 was about 0.28 sq. cm/s. This value was used to estimate the average CO2 flux from soil: 0.26 g C/sq. m/day in December 1989, 0.13 g C/sq. m/day in January 1990 and 0.07 g C/sq. m/day in February 1990. Thus a minimal total of about 13.8 g C/sq. m had been released from the tundra soil during the 90 days from December 1989 to February 1990. Using the study by Kelley et al. (1968) and assuming that the minimal CO2 transfer coefficient is also applicable for the entire tundra and Northern Taiga zones between September and June, the total emission from this region would amount to 0.23 x 10**15 g of carbon. The main source of this CO2 probably originated from microbial oxidation of soil organic matter. This assertion is supported by the existence of a relatively warm layer in the frozen soil at 40-120 cm depth. This warm layer was about 10-40 C higher than the ambient air, or about 5-10 C higher than the soil surface, and its moisture content was also higher than the surrounding layers.Key words: CO2 flux, Siberian tundra, soil temperature, moisture contentOn a &eacute;valu&eacute; l'&eacute;mission de CO2 provenant du sol dans le nord-est sib&eacute;rien, durant la p&eacute;riode allant de d&eacute;cembre 1989 &agrave; f&eacute;vrier 1990. On a mesur&eacute; les concentrations du CO2 ambiant pr&egrave;s du sol et &agrave; 1 m de la couverture de neige, &agrave; l'aide d'un analyseur de gaz infrarouge. On a calcul&eacute; les flux du CO2 &agrave; travers le couvert nival &agrave; partir des diff&eacute;rences de ces deux valeurs et des coefficients de transfert du CO2 pr&eacute;d&eacute;termin&eacute;s pour divers taux de flux &agrave; travers une couche de neige. On a aussi observ&eacute; simultan&eacute;ment la temp&eacute;rature et la teneur en humidit&eacute; des profils p&eacute;dologiques. Le coefficient de transfert moyen du CO2 pour la neige tass&eacute;e mesur&eacute; durant l'hiver de 1989-90 &eacute;tait d'environ 0,28 cm&sup2;/s. Cette valeur a servi &agrave; estimer le flux moyen du CO2 provenant du sol: 0,26 g C/m&sup2;/jour en d&eacute;cembre 1989, 0,13 g C/m&sup2;/jour en janvier 1990 et 0,07 g C/m&sup2;/jour en f&eacute;vrier 1990. Par cons&eacute;quent, un total minimal d'environ 13,8 g C/m&sup2; a &eacute;t&eacute; lib&eacute;r&eacute; du sol de la toundra au cours des 90 jours allant de d&eacute;cembre &agrave; f&eacute;vrier 1990. En nous servant de l'&eacute;tude men&eacute;e pr&eacute;c&eacute;demment par Kelley et al. (1968) et en supposant que le coefficient minimal de transfert du CO2 s'applique aussi &agrave; l'ensemble des zones de toundra et de ta&iuml;ga septentrionale entre septembre et juin, l'&eacute;mission totale provenant de cette r&eacute;gion se monterait &agrave; 0,23 x 10**15 g de carbone. La source principale de ce CO2 venait probablement de l'oxydation microbienne de la mati&egrave;re organique contenue dans le sol. Cette assertion est soutenue par l'existence d'une couche de temp&eacute;rature relativement &eacute;lev&eacute;e dans le sol gel&eacute;, qui se trouve de 40 &agrave; 120 cm de profondeur. La temp&eacute;rature de cette couche &eacute;tait de 10 &agrave; 40 &deg;C plus &eacute;lev&eacute;e que l'air ambiant, ou environ de 5 &agrave; 10 &deg;C plus &eacute;lev&eacute;e que la surface du sol, et sa teneur en eau &eacute;tait aussi plus &eacute;lev&eacute;e que les couches adjacentes.Mots cl&eacute;s : flux de CO2, toundra sib&eacute;rienne, temperature du sol, teneur en ea

Bounded-Angle Spanning Tree: Modeling Networks with Angular Constraints

We introduce a new structure for a set of points in the plane and an angle $\alpha$, which is similar in flavor to a bounded-degree MST. We name this structure $\alpha$-MST. Let $P$ be a set of points in the plane and let $0 < \alpha \le 2\pi$ be an angle. An $\alpha$-ST of $P$ is a spanning tree of the complete Euclidean graph induced by $P$, with the additional property that for each point $p \in P$, the smallest angle around $p$ containing all the edges adjacent to $p$ is at most $\alpha$. An $\alpha$-MST of $P$ is then an $\alpha$-ST of $P$ of minimum weight. For $\alpha < \pi/3$, an $\alpha$-ST does not always exist, and, for $\alpha \ge \pi/3$, it always exists. In this paper, we study the problem of computing an $\alpha$-MST for several common values of $\alpha$. Motivated by wireless networks, we formulate the problem in terms of directional antennas. With each point $p \in P$, we associate a wedge $W_p$ of angle $\alpha$ and apex $p$. The goal is to assign an orientation and a radius $r_p$ to each wedge $W_p$, such that the resulting graph is connected and its MST is an $\alpha$-MST. (We draw an edge between $p$ and $q$ if $p \in W_q$, $q \in W_p$, and $|pq| \le r_p, r_q$.) Unsurprisingly, the problem of computing an $\alpha$-MST is NP-hard, at least for $\alpha=\pi$ and $\alpha=2\pi/3$. We present constant-factor approximation algorithms for $\alpha = \pi/2, 2\pi/3, \pi$. One of our major results is a surprising theorem for $\alpha = 2\pi/3$, which, besides being interesting from a geometric point of view, has important applications. For example, the theorem guarantees that given any set $P$ of $3n$ points in the plane and any partitioning of the points into $n$ triplets, one can orient the wedges of each triplet {\em independently}, such that the graph induced by $P$ is connected. We apply the theorem to the {\em antenna conversion} problem

LHC Signature of Mirage Mediation

We study LHC phenomenology of mirage mediation scenario in which anomaly and modulus contributions to soft SUSY breaking terms are comparable to each other. A Monte Carlo study of mirage mediation, with model parameters $\alpha=1$,$M_0=500$ GeV, $n_M=1/2$, $n_H=1$ and $\rm{tan}\beta=10$, is presented. It is shown that masses of supersymmetric particles can be measured in a model independent way, providing information on SUSY breaking sector. In particular, the mass ratio of gluino to the lightest neutralino for the benchmark scenario is determined to be 1.9 \lesssim m_{\tildeg}/m_{\tilde\chi_1^0} \lesssim 3.1, well reproducing theoretical input value of $m_{\tilde g}/m_{\tilde\chi_1^0} \simeq 2.5$ which is quite distinctive from the predictions $m_{\tilde g}/m_{\tilde\chi_1^0} \gtrsim 6$ of other SUSY scenarios in which gaugino masses are unified at the GUT scale. The model parameters of mirage mediation can be also determined from various kinematic distributions

Diffusiophoresis of latex driven by anionic nanoparticles and their counterions

Hypothesis Diffusiophoresis of colloidal latex particles has been reported for molecular anions and cations of comparable size. In the present study, this phenomenon is observed for two types of charged colloids acting as multivalent electrolyte: (i) anionic charge-stabilised silica nanoparticles or (ii) minimally-charged sterically-stabilised diblock copolymer nanoparticles. Experiments Using a Hele-Shaw cell, a thin layer of relatively large latex particles is established within a sharp concentration gradient of nanoparticles by sequential filling with water, latex particles and nanoparticles. Asymmetric diffusion is observed, which provides strong evidence for diffusiophoresis. Quantification involves turbidity measurements from backlit images. Findings The latex particles diffuse across a concentration gradient of charged nanoparticles and the latex concentration front scales approximately with time1/2. Moreover, the latex particle flux is inversely proportional to the concentration of background salt, confirming electrostatically-driven motion. These observations are consistent with theory recently developed to account for diffusiophoretic motion driven by multivalent ions

Charged Cylindrical Collapse of Anisotropic Fluid

Following the scheme developed by Misner and Sharp, we discuss the dynamics of gravitational collapse. For this purpose, an interior cylindrically symmetric spacetime is matched to an exterior charged static cylindrically symmetric spacetime using the Darmois matching conditions. Dynamical equations are obtained with matter dissipating in the form of shear viscosity. The effect of charge and dissipative quantities over the cylindrical collapse are studied. Finally, we show that homogeneity in energy density and conformal flatness of spacetime are necessary and sufficient for each other.Comment: 19 pages, accepted for publication in Gen. Relativ. Gra

Block copolymer nanoparticles are effective dispersants for micrometer-sized organic crystalline particles

Well-defined sterically stabilized diblock copolymer nanoparticles of 29 nm diameter are prepared by RAFT aqueous emulsion polymerization of methyl methacrylate using a dithiobenzoate-capped poly(glycerol monomethacrylate) precursor. These nanoparticles are evaluated as a dispersant for the preparation of organic crystalline microparticles via ball milling. This is exemplified for azoxystrobin, which is a broad-spectrum fungicide that is widely used to protect various food crops. Laser diffraction and optical microscopy studies indicate the formation of azoxystrobin microparticles of approximately 2 μm diameter after ball milling for 10 min at 400 rpm. Nanoparticle adsorption at the surface of these azoxystrobin microparticles is confirmed by electron microscopy studies. The extent of nanoparticle adsorption on the azoxystrobin microparticles can be quantified using a supernatant assay based on solution densitometry. This technique indicates an adsorbed amount of approximately 5.5 mg m–2, which is sufficient to significantly reduce the negative zeta potential exhibited by azoxystrobin. Moreover, this adsorbed amount appears to be essentially independent of the nature of the core-forming block, with similar data being obtained for both poly(methyl methacrylate)- and poly(2,2,2-trifluoroethyl methacrylate)-based nanoparticles. Finally, X-ray photoelectron spectroscopy studies confirm attenuation of the underlying N1s signal arising from the azoxystrobin microparticles by the former adsorbed nanoparticles, suggesting a fractional surface coverage of approximately 0.24. This value is consistent with a theoretical surface coverage of 0.25 calculated from the adsorption isotherm data. Overall, this study suggests that sterically stabilized diblock copolymer nanoparticles may offer a useful alternative approach to traditional soluble copolymer dispersants for the preparation of suspension concentrates affecting the context of agrochemical applications

How do charged end-groups on the steric stabilizer block influence the formation and long-term stability of Pickering nanoemulsions prepared using sterically stabilized diblock copolymer nanoparticles?

Reversible addition–fragmentation chain transfer (RAFT) solution polymerization is used to prepare well-defined poly(glycerol monomethacrylate) (PGMA) chains bearing carboxylic acid, tertiary amine, or neutral end-groups. Each of these PGMA precursors was then chain-extended in turn via RAFT aqueous emulsion polymerization of 2,2,2-trifluoroethyl methacrylate to form spherical nanoparticles as confirmed by transmission electron microscopy (TEM) analysis. Dynamic light scattering studies indicated an intensity-average diameter of approximately 25 nm. Aqueous electrophoresis measurements confirmed that the amine-functional nanoparticles became cationic at low pH owing to end-group protonation. In contrast, carboxylic acid-functional nanoparticles became appreciably anionic at pH 10 owing to end-group ionization. Finally, nanoparticles bearing neutral end-groups exhibited zeta potentials close to zero over a range of solution pH. High-shear homogenization of n-dodecane in the presence of such sterically stabilized nanoparticles led to the formation of oil-in-water Pickering macroemulsions with volume-average diameters of 20–30 μm. High-pressure microfluidization was then used to prepare the three corresponding Pickering nanoemulsions. Each Pickering nanoemulsion was characterized by analytical centrifugation and TEM studies of the dried nanoemulsion droplets confirmed their original nanoparticle superstructure. The nanoparticle adsorption efficiency at the oil–water interface was assessed by gel permeation chromatography (using a UV detector) for each nanoparticle type at both pH 3 and 7. Nanoparticles with charged end-groups exhibited relatively low adsorption efficiency, whereas up to 90% of the neutral nanoparticles were adsorbed onto the oil droplets. This observation was supported by small-angle X-ray scattering experiments, which indicated that the packing efficiency of neutral nanoparticles around oil droplets was higher than that of nanoparticles bearing charged end-groups. Analytical centrifugation was used to evaluate the colloidal stability of the aged Pickering nanoemulsions. Pickering nanoemulsions stabilized with nanoparticles bearing charged end-groups proved to be significantly less stable than those prepared using neutral end-groups

Donor Centers and Absorption Spectra in Quantum Dots

We have studied the electronic properties and optical absorption spectra of three different cases of donor centers, D^{0}, D^{-} and D^{2-}, which are subjected to a perpendicular magnetic field, using the exact diagonalization method. The energies of the lowest lying states are obtained as function of the applied magnetic field strength B and the distance zeta between the positive ion and the confinement xy-plane. Our calculations indicate that the positive ion induces transitions in the ground-state, which can be observed clearly in the absorption spectra, but as zeta goes to 0 the strength of the applied magnetic field needed for a transition to occur tends to infinity.Comment: 5 pages, 4 figures, REVTeX 4, gzipped tar fil