Search results for "RADIATION"

Development of a general model to estimate the instantaneous, daily, and daytime net radiation with satellite data on clear-sky days

2015

Net radiation is a key variable in computing evapotranspiration and is a driving force in many other physical and biological processes. Remote sensing techniques provide an unparalleled spatial and temporal coverage of land-surface attributes, and thus several studies have attempted to estimate net radiation by combining remote sensing observations with surface and atmospheric data. However, remote sensing provides instantaneous data, when many applications and models need information at other temporal scales. In this work, a new general methodology is proposed to estimate daily and daytime net radiation and to retrieve the diurnal cycle of net radiation. Four images were acquired on differ…

Overdiagnosis and overimaging: an ethical issue for radiological protection

2019

Aims and objectives: This study aimed to analyse the key factors that influence the overimaging using X-ray such as self-referral, defensive medicine and duplicate imaging studies and to emphasize the ethical problem that derives from it. Materials and methods: In this study, we focused on the more frequent sources of overdiagnosis such as the total-body CT, proposed in the form of screening in both public and private sector, the choice of the most sensitive test for each pathology such as pulmonary embolism, ultrasound investigations mostly of the thyroid and of the prostate and MR examinations, especially of the musculoskeletal system. Results: The direct follow of overdiagnosis and overi…

Preoperative Evaluation and Treatment Planning. Zygomatic Implant Critical Zone (ZICZ) Location

2021

Collisional Broadening of Rotational Lines in the Stimulated Raman Pentad Q-Branch of CD4

1992

Self- and argon-broadening coefficients are reported for a number of Raman Q-branch transitions in the nu(1) and nu(2) + nu(4) bands of (C-12)D4 at room temperature (296 K). The coefficients display a variation with j and with C exp n (symmetry species A, E, F) that is essentially independent of collision partner and which is similar to the j- and C exp n-dependence found in previous measurements of the IR line-broadening coefficients. The rotationally inelastic collision rates previously measured by Foy et al. (1988) for (C-13)D4 (V4 = 0, 1) in collision with (C-13)D4 or Ar account for only a part of the Raman broadening rate, suggesting possibly significant contributions to the linewidths…

GW170817: Implications for the Stochastic Gravitational-Wave Background from Compact Binary Coalescences

2018

The LIGO Scientific and Virgo Collaborations have announced the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star background will add to the background from binary black holes, increasing the amplitude of the total astrophysical background relative to previous expectations. In the Advanced LIGO-Virgo frequency band most sensitive to stochastic backgrounds (near 25 Hz), we predict a total astrophysical background with amplitude $\Omega_{\rm…

Flow‐Injection Chemiluminescent Determination of Thiamine in Pharmaceutical Samples by On‐line Photodegradation

2004

Abstract A simple, sensitive, and precise method for the determination of thiamine hydrochloride in a flow‐injection system is described. The method is based on the UV irradiation of thiamine in acid medium. Then, the photo‐fragments are oxidized by permanganate in acid medium, and the resultant chemiluminescent intensity is measured. The optimum conditions for the photoreaction and for the chemiluminescence emission were investigated. The method allows the determination of thiamine, over the range 0.05(LOD)–84 mg · l−1, with a throughput of 30 h−1, and a RSD (n, 20) at 20 and 0.5 mg · l−1 of the thiamine level of 2.5 and 1.3%, respectively. The method was applied to pharmaceutical preparat…

Chemiluminometric photo-induced determination of Strychnine in a Multicommutation flow assembly

2007

This paper deals on the determination of Strychnine, a potent and dangerous pesticide and the analytical procedure is based on the photo-induced chemiluminescence of the pesticide by means of the Multicommutation continuous-flow methodology. Small segments of the pesticide solution were sequentially alternated with segments of the solution for adjusting the suitable medium for the photodegradation. The required time of UV irradiation was obtained by stopped-flow during 150 s; then, the resulting solution formed alternated segments with the oxidizing solution containing 5 × 10−3 mol l−1 Ce(IV) in 0.6 mol l−1 nitric acid. The calibration range, from 2 μg l−1 to 50 mg l−1, resulted in a linear…

High-performance liquid chromatography of lactose with evaporative light scattering detection, applied to determine fine particle dose of carrier in …

2005

A method for quantification of the fine particle dose of lactose is described, using a hydrophilic interaction chromatography (HILIC) method and evaporative light scattering detection. The HILIC method used an aminopropyl column and a mobile phase consisting of acetonitril/water (80/20, v/v) for isocratic elution. Sensitive chromatography was obtained using a low concentration of water in the extraction solvent. The detection limit (RSD10%) at an injection volume of 10 microL is 10 microg/mL. Linearity was obtained in the range of 10-80 microg/mL (R(2)0.99). A relative standard deviation (RSD) of 0.5% (N=6) demonstrated good precision of the optimized method.

DETECTION LIMITS FOR NATURAL CIRCULAR-DICHROISM OF CHIRAL COMPLEXES IN THE X-RAY RANGE

1993

Whereas both Magnetic Circular Dichroism and Faraday Rotation studies have been successfully carried out at the K-, L- and M-absorption edges of metal atoms in ferromagnetic systems, Natural optical activity of chiral complexes has not yet been detected quite unambiguously in the X-ray range. We review a number of theoretical arguments which confirm that the optical asymmetry factor gσ should be very small in the X-ray range for unoriented powdered samples, especially at the K-absorption edges. This stimulating challenge prompted us to start an intensive programme of measurements aimed at detecting natural circular dichroism in both the soft and “firm” X-ray ranges. Although some of our ex…

The 4th international comparison on EPR dosimetry with tooth enamel

2011

This paper presents the results of the 4th International Comparison of in vitro electron paramagnetic resonance dosimetry with tooth enamel, where the performance parameters of tooth enamel dosimetry methods were compared among sixteen laboratories from all over the world. The participating laboratories were asked to determine a calibration curve with a set of tooth enamel powder samples provided by the organizers. Nine molar teeth extracted following medical indication from German donors and collected between 1997 and 2007 were prepared and irradiated at the Helmholtz Zentrum Munchen. Five out of six samples were irradiated at 0.1, 0.2, 0.5, 1.0 and 1.5 Gy air kerma; and one unirradiated s…