Search results for "REF"

Effect of the reference solution in the measurement of ion activity coefficients using cells with transference at T=298.15K

2010

Abstract This work reports individual activity coefficients of ions at T = 298.15 K in aqueous solutions obtained from voltage values of the respective half-cell ion-selective-electrode and a single-junction Ag–AgCl reference electrode, filled with different reference solutions at different concentrations. For potassium and chloride ions in KCl aqueous solutions, reference solutions of KCl, NaCl, or CsCl were used. For sodium and chloride ions in aqueous NaCl solutions, reference solutions of CsCl were used. Experimental runs were performed at molalities (1, 2, and 3) m of the reference solution. The concentration of the sample solution was increased, starting from around 1 · 10−3 m, up to …

Isobaric Vapor−Liquid Equilibria of the Water + 2-Propanol System at 30, 60, and 100 kPa

1996

Isobaric vapor−liquid equilibria were obtained for the water + 2-propanol system at 30, 60, and 100 kPa. The activity coefficients were found to be thermodynamically consistent by the methods of Van Ness−Byer−Gibbs, Kojima, and Wisniak. The data were correlated with five liquid phase activity coefficient models (Margules, Van Laar, Wilson, NRTL, and UNIQUAC).

Spatial sharpening of land surface temperature for daily energy balance applications

2008

ABSTRACT Daily high spatial resolution assessment of actual evapotranspiration is essential for water management and crop water requirement estimation under stress conditions. The application of energy balance models usually requires satellite observations of radiometric surface temperat ure with high geometrical and temporal resolutions. By now, however, high spatial resolution (~ 100 m) is available with low time fre quency (approximately every two weeks); at the opposite daily acquisition are characterised by poor spatial resolution. The analysis of vegetation index (VI) and land surface temperature (LST) spatial relationship, shows in substance a scale invariant behaviour [1] ; this con…

The Separating Role of Collateral Requirements in Credit Markets with Asymmetric Information

2001

In this paper we test Bester's (1985, 1987) prediction about the separating role of contracts that involve both interest rates and collateral requirements in credit markets. To test this prediction we use data from natural credit markets and controlled experiments. Using a sample of credits to small and medium size firms in Valencia, Spain, we relate two different types of contracts with the ex post risk type of the borrower and other relevant variables. We then design two incentive compatible contracts and analyze decisions under two different experimental treatments, one with moral hazard. Our empirical results confirm that borrowers of ex post lower risk choose contracts with higher coll…

Self-referral to chest pain units: results of the German CPU-registry

2012

Chest pain units (CPUs) are increasingly established in emergency cardiology services. With improved visibility of CPUs in the population, patients may refer themselves directly to these units, obviating emergency medical services (EMS). Little is known about characteristics and outcomes of self-referred patients, as compared with those referred by EMS. Therefore, we described self-referral patients enrolled in the CPU-registry of the German Cardiac Society and compared them with those referred by EMS.From 2008 until 2010, the prospective CPU-registry enrolled 11,581 consecutive patients. Of those 3789 (32.7%) were self-referrals (SRs), while 7792 (67.3%) were referred by EMS. SR-patients w…

Kinematic characteristics of barefoot sprinting in habitually shod children

2018

Background Anecdotally, a wide variety of benefits of barefoot running have been advocated by numerous individuals. The influence of the alterations in the properties of the shoe on the running movement has been demonstrated in adults at submaximal jogging speeds. However, the biomechanical differences between shod and barefoot running in children at sprinting speeds and the potential developmental implications of these differences are still less examined. The purpose was to determine the potential differences in habitually shod children’s sprint kinematics between shod and barefoot conditions. Methods Ninety-four children (51 boys and 43 girls; 6–12 years-old; height, 135.0 ± 0.12 m; body…

2021

Functional proprioceptive information is required to allow an individual to interact with the environment effectively for everyday activities such as locomotion and object manipulation. Specifically, research suggests that application of compression garments could improve proprioceptive regulation of action by enhancing sensorimotor system noise in individuals of different ages and capacities. However, limited research has been conducted with samples of elderly people thus far. This study aimed to examine acute effects of wearing knee-length socks (KLS) of various compression levels on ankle joint position sense in community-dwelling, older adults. A total of 26 participants (12 male and 14…

Assessing drought vulnerability and adaptation among farmers in Gadaref region, Eastern Sudan

2018

Agricultural productivity in rural areas is severely affected by climate variability, and this elevates the vulnerability of rural households to food insecurity. This study examines the socio-economic vulnerability of farmers who are susceptible to droughts in the five agricultural-based regions of Gadaref, Eastern Sudan. A survey was carried out in 500 households to collect data on socio-economic and livelihood indicators. The data analyzed from these indicators were used to generate the three components of drought vulnerability: exposure, sensitivity and adaptive capacity. The analysis revealed that the regions deemed to be most vulnerable to both drought and climate variability were also…

Adaptive scheduling of acceleration and gyroscope for motion artifact cancelation in photoplethysmography

2022

Background and objective: Recently, various algorithms have been introduced using wrist-worn photo-plethysmography (PPG) to provide high accuracy of instantaneous heart rate (HR) estimation, including during high-intensity exercise. Most studies focus on using acceleration and/or gyroscope signals for the motion artifact (MA) reference, which attenuates or cancels out noise from the MA-corrupted PPG signals. We aim to open and pave the path to find an appropriate MA reference selection for MA cancelation in PPG.Methods: We investigated how the acceleration and gyroscope reference signals correlate with the MAs of the distorted PPG signals and derived both mathematically and experimentally a…

Perfusion MRI in normal and abnormal pituitary gland. A preliminary study.

1997

Perfusion MRI (magnetic resonance imaging) of the pituitary gland was performed in 20 healthy volunteers and 63 patients with various lesions involving the pituitary gland. All patients underwent sequential contrast-enhanced MRI using spoiled gradient recalled sequences with high temporal resolution (7 seconds). Four pituitary areas (pituitary stalk, posterior lobe, postero-superior, and antero-inferior adenohypophysis) were tested with a selected region of interest. Maximal contrast percentual variation was calculated. The timing of enhancement in normal patients matched perfectly with normal pituitary vascularization. Abnormal timing in pathological condition was investigated.