781 research outputs found

    Operating manual for the RRL 8 channel data logger

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    A data collection device which takes measurements from external sensors at user specified time intervals is described. Three sensor ports are dedicated to temperature, air pressure, and dew point. Five general purpose sensor ports are provided. The user specifies when the measurements are recorded as well as when the information is read or stored in a minicomputer or a paper tape

    Rank Maximal Matchings -- Structure and Algorithms

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    Let G = (A U P, E) be a bipartite graph where A denotes a set of agents, P denotes a set of posts and ranks on the edges denote preferences of the agents over posts. A matching M in G is rank-maximal if it matches the maximum number of applicants to their top-rank post, subject to this, the maximum number of applicants to their second rank post and so on. In this paper, we develop a switching graph characterization of rank-maximal matchings, which is a useful tool that encodes all rank-maximal matchings in an instance. The characterization leads to simple and efficient algorithms for several interesting problems. In particular, we give an efficient algorithm to compute the set of rank-maximal pairs in an instance. We show that the problem of counting the number of rank-maximal matchings is #P-Complete and also give an FPRAS for the problem. Finally, we consider the problem of deciding whether a rank-maximal matching is popular among all the rank-maximal matchings in a given instance, and give an efficient algorithm for the problem

    Solid-state characterization of novel active pharmaceutical ingredients: Cocrystal of a salbutamol hemiadipate salt with adipic acid (2:1:1) and salbutamol hemisuccinate salt.

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    The production of salt or cocrystalline forms is a common approach to alter the physicochemical properties of pharmaceutical compounds. The goal of this work was to evaluate the impact of anion choice (succinate, adipate, and sulfate) on the physicochemical characteristics of salbutamol forms. Novel crystals of salbutamol were produced by solvent evaporation: a cocrystal of salbutamol hemiadipate with adipic acid (salbutamol adipate, SA), salbutamol hemisuccinate tetramethanolate (SSU.MeOH), and its desolvated form (SSU). The crystalline materials obtained were characterized using thermal, X-ray, nuclear magnetic resonance, Fourier transform infrared spectroscopy, dynamic vapor sorption (DVS), and elemental analysis. The crystal forms of SA and SSU.MeOH were determined to be triclinic, (Pī), and monoclinic, (P21/n), respectively. DVS analysis confirmed that SSU and SA do not undergo hydration under increased relative humidity. Both thermal and elemental analyses confirmed the stoichiometry of the salt forms. The aqueous solubilities of SA and SSU were measured to be 82 ± 2 mg/mL (pH 4.5 ± 0.1) and 334 ± 13 mg/mL (pH 6.6 ± 0.1), respectively. Measured values corresponded well with the calculated pH solubility profiles. The intrinsic dissolution rate of cocrystallized SA was approximately four times lower than that of SSU, suggesting its use as an alternative to more rapidly dissolving salbutamol sulfate

    Longitudinal Evaluations of Objectively Measured Physical Activity: Capturing the Full Spectrum of Duration and Intensity

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    Most physical activity research to date narrows its focus toward intensities and durations only encompassed in the Physical Activity Guidelines of moderate to vigorous intensity in at least 10 minute bouts (MVPA-10). Examining activity in this manner excludes light activity and shorter bouts, sometimes referred to as baseline physical activity (BPA) as it consists of the activity accumulated during daily life at durations and/or intensities below what is recommended. This dissertation provides an evaluation of the entire spectrum of physical activity (PA). Physical activity was studied in a unique way by looking at MVPA-10, then adding shorter bouts and light intensity to see if these additions further influence study outcomes. This dissertation incorporated this concept into the analyses while linking behavioral investigations of physical activity to a physiological investigation of how such activity influences adiposity and weight. Thus, it transitioned from what characteristics influence physical activity behavior to how physical activity influences health. Three separate papers used this concept to 1) examine the intrapersonal-level determinants of the full spectrum of PA 2) examine how the total number of life events and the self-reported stress of life events influences the full spectrum of PA; and 3) examine the longitudinal relationship of the full spectrum of PA with adiposity and weight. This dissertation used objectively measured physical activity data collected as part of The Energy Balance Study to examine the three specific aims. The purpose of the Energy Balance Study was to examine the extent to which variation in total energy expenditure (TEE) and variation in total energy intake (TEI) contribute to changes in body weight and fat among adults. A secondary aim was to examine specific components of TEE and TEI that drive changes in body weight and fat. This dissertation contributes answers to this secondary aim, by examining the physical activity component of TEE. Study 1 showed that intrapersonal variables within categories of biological, socioeconomic, family structure, behavioral, and psychological can influence activity. The associated characteristics differ based on whether physical activity is quantified as MVPA-10, total MVPA, or total PA. Adding components of baseline PA, first short bouts of total MVPA followed by light intensity PA influences the results. In the second study, the average number and associated stress of life events per quarter did not have much influence on physical activity. However, many life events when examined separately had significant associations with MVPA-10, total MVPA and total PA. For young adult men, changing jobs and marriage had negative impacts on activity while starting/ending a relationship and beginning a mortgage had positive influences. For young adult women, starting a new job, moving, engagement, and the loss of a family/friend had negative consequence while quitting a job resulted in increases in PA. The degree of influence on activity often went beyond the typical recommendations of MVPA in 10 minute bouts. In the third study, physical activity had an influence on various anthropometric measures and varied by gender. The accumulation of greater amounts of activity was associated with a lower body fat percentage for both men and women. There were also associations with PA for waist circumference, hip circumference, and BMI for the women. For all anthropometric associations there were similar degrees of association for MVPA-10 and total MVPA, suggesting that the accumulation of all MVPA regardless of bout length can have a similar influence on anthropometrics. The association of anthropometrics with total PA was typically half of the impact when comparing the MVPA categories. Thus an increase of MVPA has a greater influence on anthropometric outcomes than an increase in total PA

    Impact of alternative solid state forms and specific surface area of high-dose, hydrophilic active pharmaceutical ingredients on tabletability

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    YesIn order to investigate the effect of using different solid state forms and specific surface area (TBET) of active pharmaceutical ingredients on tabletability and dissolution performance, the mono- and dihydrated crystalline forms of chlorothiazide sodium and chlorothiazide potassium (CTZK) salts were compared to alternative anhydrous and amorphous forms, as well as to amorphous microparticles of chlorothiazide sodium and potassium which were produced by spray drying and had a large specific surface area. The tablet hardness and tensile strength, porosity, and specific surface area of single-component, convex tablets prepared at different compression pressures were characterized. Results confirmed the complexity of the compressibility mechanisms. In general it may be concluded that factors such as solid-state form (crystalline vs amorphous), type of hydration (presence of interstitial molecules of water, dehydrates), or specific surface area of the material have a direct impact on the tabletability of the powder. It was observed that, for powders of the same solid state form, those with a larger specific surface area compacted well, and better than powders of a lower surface area, even at relatively low compression pressures. Compacts prepared at lower compression pressures from high surface area porous microparticles presented the shortest times to dissolve, when compared with compacts made of equivalent materials, which had to be compressed at higher compression pressures in order to obtain satisfactory compacts. Therefore, materials composed of nanoparticulate microparticles (NPMPs) may be considered as suitable for direct compaction and possibly for inclusion in tablet formulations as bulking agents, APIs, carriers, or binders due to their good compactibility performanceSolid State Pharmaceutical Cluster (SSPC), supported by Science Foundation Ireland under Grant No. 07/SRC/B1158

    Low fitness partially explains resting metabolic rate differences between African American and white women

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    Background High levels of obesity among African American women have been hypothesized to be partially resultant from a lower resting metabolic rate compared with white women. The aim of the current study was to determine if differences in cardiorespiratory fitness and moderate-to-vigorous physical activity are associated with differences in resting metabolic rate among free-living young adult African American women and white women. Methods Participants were 179 women (white women n = 141, African American women n = 38, mean age = 27.7 years). Resting metabolic rate was measured using indirect calorimetry, body composition using dual energy x-ray absorptiometry, cardiorespiratory fitness via maximal treadmill test, and moderate-to-vigorous physical activity using an activity monitor. Results African American women had higher body mass index, fat mass, and fat-free mass compared with white women but lower levels of cardiorespiratory fitness. No differences were observed between African American and white women in resting metabolic rate when expressed as kcal/day (1390.8 ± 197.5 vs 1375.7 ± 173.6 kcal/day, P =.64), but African American women had a lower resting metabolic rate when expressed relative to body weight (2.56 ± 0.30 vs 2.95 ± 0.33 mL/kg/min,

    Fast relaxation in a fragile liquid under pressure

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    The incoherent dynamic structure factor of ortho-terphenyl has been measured by neutron time-of-flight and backscattering technique in the pressure range from 0.1 MPa to 240 MPa for temperatures between 301 K and 335 K. Tagged-particle correlations in the compressed liquid decay in two steps. The alpha-relaxation lineshape is independent of pressure, and the relaxation time proportional to viscosity. A kink in the amplitude f_Q(P) reveals the onset of beta relaxation. The beta-relaxation regime can be described by the mode-coupling scaling function; amplitudes and time scales allow a consistent determination of the critical pressure P_c(T). alpha and beta relaxation depend in the same way on the thermodynamic state; close to the mode-coupling cross-over, this dependence can be parametrised by an effective coupling Gamma ~ n*T**{-1/4}.Comment: 4 Pages of RevTeX, 4 figures (submitted to Physical Review Letters

    The clustering instability of inertial particles spatial distribution in turbulent flows

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    A theory of clustering of inertial particles advected by a turbulent velocity field caused by an instability of their spatial distribution is suggested. The reason for the clustering instability is a combined effect of the particles inertia and a finite correlation time of the velocity field. The crucial parameter for the clustering instability is a size of the particles. The critical size is estimated for a strong clustering (with a finite fraction of particles in clusters) associated with the growth of the mean absolute value of the particles number density and for a weak clustering associated with the growth of the second and higher moments. A new concept of compressibility of the turbulent diffusion tensor caused by a finite correlation time of an incompressible velocity field is introduced. In this model of the velocity field, the field of Lagrangian trajectories is not divergence-free. A mechanism of saturation of the clustering instability associated with the particles collisions in the clusters is suggested. Applications of the analyzed effects to the dynamics of droplets in the turbulent atmosphere are discussed. An estimated nonlinear level of the saturation of the droplets number density in clouds exceeds by the orders of magnitude their mean number density. The critical size of cloud droplets required for clusters formation is more than 20μ20 \mum.Comment: REVTeX 4, 15 pages, 2 figures(included), PRE submitte
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