bluuebunny/crossref_metadata_2025 huggingface dataset:
A post-processing technique to estimate the signal-to-noise ratio and remove echosounder background noise
Authors: De Robertis Alex , Higginbottom Ian
Published: February 2017

De Robertis, A., and Higginbottom, I. 2007. A post-processing technique to estimate the signal-to-noise ratio and remove echosounder background noise. – ICES Journal of Marine Science, 64: 1282–1291. A simple and effective post-processing technique to estimate echosounder background-noise levels and signal-to-noise ratios (SNRs) during active pinging is developed. Similar to other methods of noise estimation during active pinging, this method assumes that some portion of the sampled acoustic signal is dominated by background noise, with a negligible contribution from the backscattered transmit signal. If this assumption is met, the method will provide robust and accurate estimates of background noise equivalent to that measured by the receiver if the transmitter were disabled. It provides repeated noise estimates over short intervals of time without user intervention, which is beneficial in cases where background noise changes over time. In situations where background noise is dominant in a portion of the recorded signal, it is straightforward to make first-order corrections for the effects of noise and to estimate the SNR to evaluate the effects of background noise on acoustic measurements. Noise correction and signal-to-noise-based thresholds have the potential to improve inferences from acoustic measurements in lower signal-to-noise situations, such as when surveying from noisy vessels, using multifrequency techniques, surveying at longer ranges, and when working with weak acoustic targets such as invertebrates and fish lacking swimbladders.
Elevated CO2 and plant growth: cellular mechanisms and responses of whole plants
Authors: Taylor Gail , Ranasinghe Sananthanie , Bosac Creana , Gardner S.D.L. , Ferris Rachel
Published: February 2017

Much research has focused on the photosynthetic responses of plants to elevated CO2 , with less attention given to the post-photosynthetic events which may lead to changes in the growth of tissues, organs and whole plants. The aim of this review is to identify how plant growth is altered in elevated CO2 and to determine which growth processes or cellular mechanisms are sensitive to carbon supply.

For leaves, both the expansion of individual leaves and the initiation of leaf primordia are stimulated in elevated CO2. When lamina growth is promoted, this is usually associated with increased leaf cell expansion rather than increased leaf cell production. Using several clones of hybrid poplar (Populus euramericana, P. interamericana) two native herbs (Plantago media, Sanguisorba minor) and bean (Phaseolus vulgaris) we have identified the mechanism through which leaf cell expansion is promoted in elevated CO2. Changes in the water relations, turgor pressure (P) and yield turgor (Y) of growing leaves cannot explain increased cell expansion; this appears to occur because cell wall loosening is promoted, as suggested by three pieces of evidence. (i) The rate of decline of water potential (ψ) with time is accelerated when growing leaves are placed in psychrometers and allowed to relax, (ii) Instron-measured cell wall extensibility (WEX), is greater for leaves exposed to elevated CO2 and (iii) the activity of the putative wall loosening enzyme, XET is increased for leaves of P. vulgaris exposed to elevated CO2. Species differences do, however, exist; in the herb Lotus corniculatus small stimulations of leaf growth in elevated CO2 are due to increased leaf cell production and decreased cell size in elevated CO2. These results are discussed in relation to the concept of functional types.

There is evidence to suggest that both cell production and cell expansion are promoted in roots of plants exposed to elevated CO2. For native herbs (Anthyllis vulneraria, Lotus corniculatus, P. media and S. minor), increased root growth in elevated CO2 is due to increased cell elongation. In contrast to leaves, this appears to occur because both root cell turgor pressure (P) and root cell wall extensibility (WEX) are promoted by exposure of shoots to elevated CO2. In longer-term studies on root growth, the effects of additional carbon on the production of root primordia and root branching are of overriding importance, suggesting that carbon supply may influence some aspect of the cell cycle, when effects on the extension of individual roots may not be apparent.
An anisotropic minijets model for the GRB prompt emission
Authors: Barniol Duran R. , Leng M. , Giannios D.
Published: February 2017

In order to explain rapid light-curve variability without invoking a variable source, several authors have proposed ‘minijets’ that move relativistically relative to the main flow of the jet. Here, we consider the possibility that these minijets, instead of being isotropically distributed in the comoving frame of the jet, form primarily perpendicular to the direction of the flow, as the jet dissipates its energy at a large emission radius. This yields two robust features. First, the emission is significantly delayed compared with the isotropic case. This delay allows for the peak of the afterglow emission to appear while the source is still active, in contrast to the simplest isotropic model. Secondly, the flux decline after the source turns off is steeper than the isotropic case. We find that these two features are realized in gamma-ray bursts (GRBs). (1) The peak of most GeV light curves (ascribed to the external shock) appears during the prompt emission phase. (2) Many X-ray light curves exhibit a period of steep decay, which is faster than that predicted by the standard isotropic case. The gamma-ray generation mechanism in GRBs, and possibly in other relativistic flows, may therefore be anisotropic.
Changes in the activities of ornithine decarboxylase, putrescine N-methyltransferase and N-methylputrescine oxidase in tobacco roots in relation to nicotine biosynthesis
Authors: Mizusaki Shigenobu , Tanabe Yoko , Noguchi Masao , Tamaki Einosuke
Published: February 2017

Changes in ornithine decarboxylase, putrescine N-methyltransferase and N-methylputrescine oxidase activities in response to some treatments were investigated using hydroponically grown tobacco plants. Decapitation of shoots brought about marked elevation of the three enzyme activities, which reached their peaks 24 hr after decapitation, then declined. An excellent correlation was observed between the accumulation of nicotine and changes in the three root enzyme activities. Administration of IAA at 2.5 to 5 μconcentration significandy increased these enzyme activities in roots of decapitated plants but higher concentrations of IAA prevented the rise in enzyme activities promoted by decapitation. Nicotine strongly inhibited the rise in enzyme activities in roots of decapitated plants in all cases. The results suggest that these enzymes are under the control of a common regulatory system, in which auxin and nicotine are important components. Ornithine decarboxylase was present in all the plants examined, but putrescine N-methyltransferase and N-mediylputrescine oxidase were detected only in the roots of tobacco, Datura and Atropa plants.
The Application of Radiophotoluminescent Glass to Gamma Dosimetry in Mixed n-Gamma Fields
Authors: Croft S. , Weaver D.R. , Heffer P.J.H.
Published: February 2017

High Z radiophotoluminescent glass of British manufacture has been studied with a view to using it as a ? ray dosemeter in mixed n-? fields at ambient and elevated temperatures. Environments such as these are widespread amongst nuclear enginering, accident dosimetry and military application areas. The radiation response of the glass has been fully characterised and the results are presented. The photon response over the energy range 16 keV-7 MeV has been determined and interpreted within the framework of a simplified model. The neutron response from thermal energies to 15 MeV has been measured using reactor and accelerator based sources. The fast neutron response was found to be small, although the thermal neutron sensitivity is too high for most in-core applications without a thermal neutron shield. The results are also compared with new measurements of the neutron response of Toshiba FD7 glass over the energy range thermal - 2.2 MeV. The signal build-up and fade characteristics of the dosemeter at ambient temperatures and 100 oC are presented for irradiations carried out both at ambient and 100 oC. Acceptable stability is found at these elevated temperatures. The potential use of this high Z glass in tandem with low Z beryllium oxide dosemeters as a measure of gamma ray spectra is also discussed.
Thermoluminescence Dating of Pleistocene Travertine
Authors: Reddmann Th. , Schüttlekopf H.
Published: February 2017

We investigated the thermoluminescence characteristics of travertine samples from a deposit at Bad-Cannstatt, Stuttgart, South West Germany. This location is known as a prehistoric hunting place of homo erectus, whose age has been approximated to about 200,000 years. The calcite material has been found to show a high fraction of clay impurities. A pre-treatment using heavy liquid separation techniques resulted, however, in a good reproducibility of the TL signal. On the other hand, a high degree of spatial homogeneity of the U/Th distribution has been found. In addition 238U, 234U and 230Th concentrations were determined in the samples using radiochemical analysis. The derived isotope ratios and the paleodoses prove that a substantial fraction of the uranium must have been removed after deposition. A best fit method is used to correct for this loss and to derive ages for the material.
Investigation of Thermoluminescence Efficiencies at High Laser Heating Rates
Authors: Abtahi A. , Braunlich P. , Haugan T. , Kelly P.
Published: February 2017

The generation of heating rates, q, approaching 10,000 oC.s-1 is readily possible by heating thin-layer thermoluminescence dosemeter configurations with a CO2 laser. Because the signal to noise ratio is expected to be proportional to q, rapid laser heating has attracted some attention. On the negative side, the thermoluminescence efficiency is believed to decrease significantly in several TLD materials as q passes a certain value (e.g. 2 oC.s-1 in LiF:Mg,Ti and 0.5 oC.s-1 in CaF2:Mn). Therefore, a study of the thermoluminescence efficiency as a function of q is of great interest for applications of laser heating in thermoluminescence dosimetry. Such a study has, however, become possible only after techniques for the generation of reproducible laser beams with uniform intensity profiles were developed. In this paper we present experimental results obtained with LiF:Mg,Ti and CaSO4:Dy for q in the range from less than 4 oC.s-1 up to 5500 oC.s-1.
Dose Mean Lineal Energy for Fast Neutrons in Small Spherical Targets
Authors: Leuthold G. , Burger G.
Published: February 2017

The calculation of microdosimetric distributions for neutrons, has so far been performed for target sizes in the micrometre region, where the LET approximation is valid. In small spherical targets straggling and d ray effects strongly influence the energy deposition. The dose mean lineal energy -D can, however, be calculated using Kellerer's proximity function approach from a computer simulated ion track event pattern. In such tracks, different structural components can be distinguished. The calculation was performed for the main constituents of secondary charged particle spectra produced by 14.1 MeV neutrons in tissue. The influence of d rays on the energy deposition in small targets of 1 to 100 nm diameter is shown and the deviation from the LET approximation is discussed.
A New Concept in Microdosimetry to Evaluate the Quality Factor for Neutrons and Photons
Authors: Al-Affan I.A.M.
Published: February 2017

Microdosimetry is potentially a powerful technique for determining radiation quality. Examination of its use has led to the development of a new method by which the effective quality factor Q can be based on the microdosimetric parameter - and the number of ionisations in the DNA double strand diameter (2 nm). Two formulae to evaluate Q have been derived for cell inactivation and other end points of high RBE (e.g. lens opacification). Q values using the first formula were: 1.13, ~4.5, 3.5, 6, 61, and 24, for 60Co(?), 270 eV X rays, 250 KV X rays, 3H(ß), 0.4 MeV and 15 MeV neutrons, respectively. For lens opacification Q values were 1.14, 4.5, 4.4, 9, 230, and 66, respectively, for the above radiations. The above values of Q agree well with published experimental values of RBE, at low doses. The advantage of the present method is that it can predict Q for two radiations of the same -D.
Intercomparison of the Chlorobenzene-Ethanol-Trimethylpentane Dosemeter and Ionisation Chamber in the M.D. Anderson Hospital CP-42 Cyclotron Neutron Field
Authors: Miljanic S. , Otte V.A. , Dvornik I. , Miljanic D.
Published: February 2017

The chlorobenzene-ethanol-trimethylpentane (CET) chemical dosemeter response to neutrons was studied earlier with neutrons of mean energies from 0.35 to 14.5 MeV. It was found that this system could be used in practice for total tissue dose determination due to nearly equivalent responses to gammas and neutrons. In this study, the response of the CET system to the neutrons produced by 42 MeV protons on beryllium was investigated. The system was irradiated in silica cells of 20 mm inner diameter, glass ampoules of 3.6 mm inner diameter, and the same type of glass ampoules placed in a plastic holder; ie. the DL-M4 dosemeter. Irradiations were performed in air or in a water phantom together with a tissue-equivalent (TE) ionisation chamber. In all cases the response of the CET system, expressed as the absorbed dose in tissue, was less than that of the TE chamber, depending on the irradiation conditions and the type of irradiation vessel. The effects of charged particle non-equilibrium and of heavy ion LET on the response of the CET system are discussed.
A Tentative Protocol for Measurement of Radon Availability from the Ground
Authors: Tanner A.B.
Published: February 2017

A procedure is being tested in order to determine its suitability for assessing the intrinsic ability of the ground at a particular site to supply 222Rn to a basement structure to be built on the site. Soil gas is sucked from a borehole probe through an alpha scintillation chamber and flow meter by a pump. The permeability of the soil is calculated from the flow rate and the pressure difference between the atmosphere and the borehole at the intake point. The diffusion coefficient is estimated from the water fraction in the soil pores. The upward migration distance for radon in such soil during one mean life is computed from an arbitrary steady pressure difference. This mean migration distance, multiplied by the measured radon concentration, gives the 'radon availability number'. Measurements at sites of known indoor radon concentration suggest that numbers below 2 kBq.m-2 indicate litte chance of elevated indoor radon and above 20 kBq.m-2 indicate that elevated indoor radon is likely. The range of uncertainty and the point-to-point and seasonal variations to be expected are under investigation.
Seasonal Variation of Radon Daughters Concentrations in the Atmosphere and in Precipitation at the Japanese Coast of the Sea of Japan
Authors: Nishikawa T. , Okabe S. , Aoki M.
Published: February 2017

The atmospheric radon daughters concentration at Fukui in the Japanese coastal region of the Sea of Japan shows a seasonal variation whose high values appear in summer and low values in winter. On the other hand, the radon daughters concentration in precipitation at Fukui and that in the maritime atmosphere over the Sea of Japan are high in winter and low in summer. It is concluded from these phenomena that the greater part of the continental radon and its daughters are transported by seasonal winds from Siberia and China to Japan across the Sea of Japan in winter. However, when the air masses approach the shore, the cumulonimbus grows and the heavy snowfall scavenges out the radon daughters from the air masses in large quantities at the Japanese coastal region of the Sea of Japan.
Measurements of the Total and Unattached Radon Daughters in a House
Authors: Kojima H. , Abe S.
Published: February 2017

Continual and simultaneous measurement of unattached radon daughters (RaA, RaB and RaC) and the total radon daughters was performed in a house under normal living conditions which include ordinary living habits, the style of house construction and the normal natural ventilation rate in Japan. The hourly concentrations of three radon daughters were obtained separately and simultaneously with a radon daughter monitor, which has air filtration and gross alpha counting systems. The instrument was automatically operated (and maintenance free) over a period of two months. The unattached atoms of radon daughters were measured with another radon daughter monitor with wire screens substituting for the filter. From the measurements for seven months from Nov. 1986 to May 1987, it can be stated that: (1) the concentration of unattached RaA is the most predominant of these daughters, and the unattached RaB is always detectable; (2) the median value of the unattached fraction, fp indicated by potential alpha energy, is around 0.04, the RaB makes a contribution of more than 30% to the overall fp; (3) the data for the unattached fraction show a typical diurnal variation, having a low level in intervals of 7 to 9 and 20 to 22 local hours. It corresponds to aerosol generation from the use of gas ranges in the house.
The OECD/CEC Radon Measurements Intercomparison: A Further Analysis of the Results
Authors: Knutson E.O.
Published: February 2017

Further analyses were performed on the data obtained from the International Intercalibration and Intercomparison Programme for Radon, Thoron and Daughters Measuring Equipment, Part I - Radon Measurement. This project is sponsored jointly by the Nuclear Energy Agency of the Organisation for Economic Cooperation and Development, and the Radiation Protection Research Programme of the Commission of European Communities. In the report for Part I, conclusions were based primarily on the analysis of variance method, comparing within-laboratory (replication) errors to between-laboratory errors. Uncertainties were reported for each measurement; however, there was no additional use of this information. The reported uncertainties have been analysed more completely, leading to the conclusion that they are not a significant source of error. Further analyses were done using the two-way analysis of variance applied to the logarithms of the data. The findings reinforce and amplify those already reported: the results from three of the laboratories agreed within replication error, but the results from the fourth laboratory differed significantly (about 9%) from the other three. The overall unexplained variance, expressed as geometric standard deviation, was 1.05.
The Value of Intercomparison in Radon Metrology
Authors: Miles J.C.H. , Sinnaeve (INVITED) J.
Published: February 2017

Several intercomparisons of active and passive techniques for the measurement of radon and its decay products have been held over the past decade in Europe, the United States of America, and Australia. The results of these intercomparisons are reviewed. In particular, the trend of results in three European intecomparisons sponsored by the Commission of the European Communities is examined. The number of laboratories participating in these exercises has increased, and an encouraging improvement of standards has taken place. Recently, the separate exercises in different regions have been coordinated by appointed regional laboratories which have compared measurement standards between themselves to provide a common frame of reference. As new laboratories continually enter the field of radon and radon decay product measurement and new or improved measurement techniques are still being developed, intercomparisons are likely to remain important in maintaining and improving standards.
Radon and Lung Cancer: An Epidemiological Study in Norway
Authors: Stranden E. , Magnus K. , James A.C. , Green B.M.R. , Strand T.
Published: February 2017

The objectives and strategy of an epidemiological study on the effects of exposure to radon in Norwegian dwellings is presented. The study is a cooperation between the National Institute of Radiation Hygiene and the Norwegian Cancer Registry in Norway and the National Radiological Protection Board of the United Kingdom, with funding by the Norwegian Cancer Society. Measurements of radon are being made in 10,000 dwellings representing all Norwegian municipalities. The houses have been selected by a stratified random sampling procedure based on data from the Central Bureau of Statistics of Norway. The number of measurements in each municipality is proportional to the number of inhabitants. The total population of Norway is about 4 million. Thus one measurement will be performed per 400 inhabitants and one in 150 homes will be measured. The potential for detecting an effect of radon exposure by such a study in Norway is unique because; (1) Radon concentrations are high and there are large regional variations. (2) Data from the Norwegian Cancer Registry is of high quality: all cancers have been subject to compulsory reporting since 1955. These data can be broken down according to municipality, sex and age. (3) In 1964/1965 a large scale survey of smoking habits was carried out in Norway. These data can also be broken down according to municipality, sex and age, and by types of smoking and smoking rate. It is intended to examine the correlation between lung cancer incidence and geographical variation in radon levels after making allowance for smoking habilts. Radon measurements were started in early 1987 and the results of the study are expected to be published in 1989.
Semi-Empirical Expressions Describing the Elastic Scattering of Slow Electrons by Molecules
Authors: Senger B. , Falk S. , Rechenmann R.V.
Published: February 2017

Practical, semi-empirical expressions are proposed, which describe the differential cross sections (DCS) and cross sections (CS) for the elastic scattering of low energy (( 200 eV) electrons by various molecules (N2, H2O). These formalisms are partly based on the screened Rutherford formula, and completed by non-Rutherfordian terms whose parameters have been determined by fitting to experimental data from the literature. These parameters were expressed in terms of simple analytical functions of the electron's energy. A satisfactory accord has been obtained over the largest part of the angular domain covered.
Radiosensitivity Parameters for Cell Survival in Tradescantia and for Chromosome Aberrations in Chinese Hamster Cells
Authors: Katz R. , Huang G.
Published: February 2017

Data for the loss of reproductive integrity of Tradescantia stamen hairs irradiated with 250 keV X rays and 0.43 and 5.6 MeV neutrons are fitted with radiosensitivity parameters from track theory, with E0 and m from X ray data while s0 and ? are then found from neutron irradiations. The X ray data display a clear shoulder with 100% survival below 0.18 Gy and a 'linear tail'. Data for abnormal metaphases and chromatid exchanges in Chinese Hamster cells have also been fitted with parameters. Parameters for abnormal metaphases are nearly identical with those obtained years ago for cell killing from data in the same paper, strongly supporting the view that cell killing arises from chromosome aberrations. These dose-response curves are also shouldered with a 'linear tail'.
Dosimetry Around Hot Particles with Microdosimetric Techniques
Authors: Grindborg J.E. , Lindborg L. , Tilikidis A. , Falk R.
Published: February 2017

After the Chernobyl accident small particles with high activities were detected on the ground. These 'hot particles' contained ß and ? emitters and sometimes a emitters. Two microdosimetric techniques have been tested, to determine experimentally the absorbed dose to tissue at distances between 2 µm and 40 µm from a 'hot particle'. With electric current measurements the dose as well as the dose mean lineal energy were determined. Traditional microdosimetric techniques also gave the single event distribution. The measurements were performed with a wall-less spherical proportional counter. The hot particle used contained only ß and ? emitters, therefore an a emitter was simulated with an a source. The dose distribution easily shows if a emitters are present. The results from the dose measurements and calculation agree within 50%. The measurements demonstrate that microdosimetric techniques are suitable for absorbed dose measurements around 'hot particles'.
Influence of the Cooling Rate on Repeatability of LiF:Mg,Cu,P Thermoluminescent Chips
Authors: Piters T.M. , Bos A.J.J.
Published: February 2017

This paper presents the results of an investigation into the change of sensitivity of LiF:Mg,Cu,P (trade name GR-200) after repeated usage. The cooling rate in the annealing procedure (10 min at 240 oC) was taken as parameter. Two different production batches of GR-200 (named A and B) were used. Cooling rates were chosen from 1 K.min-1 to approximately 230 K.min-1. The results show that the cooling rate in the annealing procedure of GR-200 is an important parameter. It influences the glow curve pattern, the sensitivity and the repeatability. Distinct differences in repeatability between different production batches were observed. For chips annealed at a high cooling rate, the sensitivity of batch A decreased 23% after 8 re-use cycles (comprising an oven anneal, irradiation and a readout) while the sensitivity of batch B decreased 3% to 6%. The results of this study indicate that a constant sensitivity of GR-200 can be obtained by giving the material an initialisation oven anneal procedure (10 min at 240 oC followed by a fast cooling to room temperature) of at least 8 times.
Optical Bleaching and Phototransfer of BeO TL Detector by Simulated Solar UV Light
Authors: Lembo L. , Pimpinella M. , Mukherjee B.
Published: February 2017

The PTTL and optical bleaching properties of BeO detectors have been investigated as a possible technique for the epidemiological studies of solar UV radiation-induced skin cancer. BeO Thermalox 995 chips irradiated with 241Am alpha particles were exposed to UV light from a high pressure mercury lamp. The UV spectrum of the lamp was corrected approximately to the solar UV spectrum by means of an appropriate optical filter combination. The UV-induced bleaching of the TL glow signal as well as the phototransfer of second readout have been investigated as a function of UV exposure.
Radon Levels Inside Residences in Mexico City
Authors: Espinosa G. , Gammage R.B.
Published: February 2017

Levels of radon were measured during winter and spring seasons inside 55 colonial and modern houses and 30 multi-family apartment buildings representative of middle and upper income families. The modern houses and apartment buildings in the southern section of the city had average radon levels exceeding 150 Bq.m-3 with a maximum single measurement of 458 Bq.m-3. The colonial houses in the central downtown section had radon levels nearly all averaging below 100 Bq.m-3. Between the ground and third floor of the apartment buildings, radon levels diminished tenfold, indicating that entry of radon-bearing soil gas was largely responsible for the elevated concentrations of radon. The radon levels in winter exceeded by about 30% the radon levels during spring. The potentially adverse health effects of these radon levels may be exacerbated by the quality of air in Mexico City which is often highly polluted during winter.
Progress in Phosphate Glass Dosimetry: Experiences and Routine Monitoring with a Modern Dosimetry System
Authors: Piesch E. , Burgkhardt B. , Vilgis M.
Published: February 2017

The modern, commercially available PLD system type Toshiba FGD-10, with flat glass dosemeters and a full automatic readout system, type tested at the PTB, allows for the measurement of Hpown to photon energies of 10 keV and, in addition, the indication of radiation quality below 100 keV as well as the direction of the radiation incidence. Due to the intrinsic pre-dose subtraction, doses of 0.03 mSv up to 8 Sv can be measured with a random uncertainty of 10%. The paper discusses long-term monitoring results on a monthly and yearly basis. Experiences in routine monitoring as well as intercomparison experiments, showed an excellent long-term stability of the system with an accuracy of measurement in the order of 1% not previously obtained with other solid state dosimetry systems. The system allows for a reliable routine evaluation also under unfavourable readout and environment conditions.
Thoron Exposure of Man: A Negligible Issue?
Authors: Steinhäusler F. , Hofmann W. , Lettner H.
Published: February 2017

The existing database on thoron (Tn) in the environment, the experimental validation of dosimetric models and potential health effects are scarce. Available information on Tn and its decay products (Tn-d) indoors and outdoors is associated with partly significant uncertainties due to methodological shortcomings. Dosimetric modelling reveals that ThB (212Pb) data are to be considered as the most important input parameter. Under typical indoor exposure conditions the dose due to Tn-d is about one order of magnitude less than from radon decay products (Rn-d). However, special circumstances have been identified where the Tn-dose contribution can exceed the corresponding Rn-d values. Several health effects have been associated with elevated exposure among workers in thoron-related industries and residents in high thoron background areas.
Measurements on, and Modelling of Diffusive and Advective Radon Transport in Soil
Authors: van der Graaf E.R. , Witteman G.A.A. , van der Spoel W.H. , Andersen C.E. , de Meijer R.J.
Published: February 2017

Results are presented of measurements on radon transport in soil under controlled conditions with a laboratory facility consisting of a stainless steel vessel (height and diameter 2 m) filled with a uniform column of sand. At several depths under the sand surface, probes are radically inserted into the vessel to measure the radon concentration in the soil gas. To study advective radon transport a perforated circular box is placed in the sand close to the bottom of the vessel. By pressurising this box, an air flow through the sand column is induced. Radon concentration profiles were measured without an air flow as a function of time, and for several values of the air flow, equilibrium radon concentration profiles were measured.
Electron Spin Resonance Readout for LiF Dosemeters
Authors: Ettinger K.V. , Eid A.M. , Forrester A.R.
Published: February 2017

Concentration of paramagnetic centres formed in lithium fluoride on ? ray irradiation was measured by means of ESR. Dose response of pure LiF powder was determined in the range between 0.5 and 6 kGy. TLD-700 powder was used in the range from 10 Gy to 9 kGy and dose response of LiF:Mg (400 ppm) was found in the range from 3 Gy to 3 kGy.
On Piezoluminescence in Irradiated Alkali Halides
Authors: Al-Hashimi A. , Eid A.M. , Ettinger K.V. , Mallard J.R.
Published: February 2017

The emission of light under application of pressure was recorded from irradiated crystals of NaCl, KCl, KBr and polycrystalline chips of LiF (TLD-100) as a function of dose of gamma rays imparted to the specimens. The paper gives details of experimental procedures and apparatus. The dose range covered was from 0.3 Gy to 1 kGy.
Laser Thermoluminescence: Thermal and Optical Aspects
Authors: Moreau Y. , Gasiot J. , Marah M. , Zangaro R. , Chassende-Baroz P.
Published: February 2017

Laser heating is a very promising technique, it introduces a new range of features, but, at the same time, new problems need to be solved. Most of our activity in the past years has been devoted to researching the optimal use of the new thermoluminescence dosemeter readers. The goal of this paper is the presentation of our latest results on laser heating of thin thermoluminescence dosemeters. We analyse the thermal response, and compare the theoretical and experimental behaviour. We measure the evolution with temperature of the quantum efficiency and the time constant of the radioluminescence. We analyse the temperature variation of the maximum of the thermoluminescence with the heating rate, and study the signal. As a tool for the simulation is developed, various TL apsects are presented for future improvements.
The Role of Vacancies in the Thermoluminescence of LiF:Ti and CaSO4:Dy
Authors: Chandra B. , Lakshmanan A.R. , Shinde S.S. , Bhatt R.C.
Published: February 2017

Since the main thermoluminescent (TL) glow peak (250 oC) and F-band optical absorption in LiF:Ti crystals are found to be almost absent after gamma ray irradiation at -196 oC, we propose that the main glow peak results from interstitial vacancy recombination. Additional doping of CaSO4:Dy with either Li+ (or Na+) brought about drastic reduction in 225 oC as well as 375 oC TL peaks. This indicates that Ca2+ vacancies are involved in the formation of traps giving rise to these TL peaks.
Energy Measurements of Thermally Stimulated Exoelectrons from LiF Single Crystals
Authors: Kubozoe T. , Watanabe Y.
Published: February 2017

In the course of energy measurements of thermally stimulated exoelectrons from LiF single crystals irradiated with X rays, the integral energy spectrum is found to be broad and to deviate from an exponential distribution, and the onset of saturation current is not around zero volts. However, with an increasing period of illumination with UV radiation just after X ray irradiation, the onset of saturation current goes toward zero volts and the energy spectrum can be approximated by an exponential distribution. The mean energy is then evaluated to be approximately 0.3 eV. Experimental spectra are compared with those of Monte Carlo calculations based on a model with an overthermal exponential distribution, taking into account electron-phonon interactions and satisfactory agreement is obtained.
The Microdosimetric Link Between Oncogenic Transformation Data with Neutrons and Charged Particles
Authors: Hall E.J. , Brenner D.J. , Hei T.K. , Miller R.C.
Published: February 2017

One of the most important challenges in biophysics is to predict the variation of biological effectiveness with radiation quality in terms of a physical quantity that can be measured or deduced from experiment. In recent years, a substantial body of data had been accumulated at the Radiological Research Laboratory involving cell lethality and oncogenic transformation, caused by: (a) Monoenergetic neutrons with energies from 200 keV to 14 MeV. (b) Charged particles in the track segment mode, with defined LET values from 10 to 150 keV.µm-1. Microdosimetric spectra have also been generated for these radiation beams. This body of data provides, for the first time, the possibility of investigating the best physical specifier of radiation quality in relation to a relevant endpoint, namely oncogenic transformation. Eight different biophysical parameters were investigated to see which, if any, were consistent with, and predictive of, the data. It was concluded that the dose-averaged quantities LETD (restricted or unrestricted) and yD (1 µm or 25 nm site size) are the best predictors of relative transformation rates for different radiations.
Mechanism of Storage of Ionising Radiation Energy in LiF:Mg, Ti Crystals
Authors: Rogalev B.I. , Mysovsky S. , Nepomnyachikh A.I. , Chernov V.G.
Published: February 2017

Ionising radiation energy is stored in LiF:Mg,Ti as a result of radiative reduction of initial divalent magnesium ion-cation vacancy dipoles (Mg2+ centres) to univalent (Mg+ centres) and atomic (Mg0 centres) states. The Mg+ centre is created through decay of self-trapped excitons near Mg2+ centres. The Mg0 centre is formed owing to electron capture by a Mg+ centre. Calculations of electronic and spatial structure and dose dependences of radiative creation of these centres have been made. The dose dependences of the F, Mg+ and Mg0 centres, radiative creation have been obtained using LiF:Mg (0.003 - 0.3 wt %) crystals irradiated by gamma rays. Comparisons of the experimental results with computed ones confirm the validity of the model used.
The Dose Response of Individual Glow Peaks in 7LiF (TLD-700) Read Out Normally and After UV Phototransfer
Authors: Perks C.A. , Marshall M.
Published: February 2017

Three complementary techniques for thermoluminescence glow curve analysis have been developed at the Harwell Laboratory. These are: non-linear least squares fitting using Podorsak's approximation for first-order kinetics: glow curve division, which involves dividing glow curves by a reference, well characterised, glow curve; and glow peak stripping. These techniques have been used to determine the sensitivity of individual glow peaks (4 - 10) in 7LiF TLD chips (TLD 700) as a function of gamma ray dose in the range 10 mGy to 20 kGy. Glow curves obtained from normal readout (linear rise in temperature with time at 1 oC.s-1 up to 374 oC) and from glow curves obtained after normal readout up to 300 oC followed by UV phototransfer (UVPT) have been analysed. The techniques developed for glow curve analysis are summarised and results presented for the dose response of individual glow peaks obtained from normal and UVPT readout. The results show that the onset of supralinearity occurs at lower doses for peaks with higher peak temperatures. However, the dose at which the peaks saturate is independent of the peak. Finally the implications of these results for models of supralinearity and saturation are discussed.
Mathematical Modelling of TL Supralinearity for Heavy Charged Particles
Authors: Horowitz (INVITED) Y.S.
Published: February 2017

Microdosimetric phenomena, not addressed by conventional kinetic calculations in the framework of 'conduction band/valence band' atomic models, play an important role in the thermoluminescence (TL) dose response. In this paper we discuss how the track interaction model (TIM), incorporating first, second and third nearest neighbour interactions, describes the alpha particle induced linear/supralinear behaviour of peaks 5,7,8 and 9 in LiF:Mg, Ti. The increasing supralinearity with glow peak temperature is shown to arise from increasing charge carrier migration distances in the luminescent recombination stage, 150 Å, 300 Å, 3000 Å and 5000 Å for peaks 5,7,8 and 9 respectively. The track interaction model should be viewed as the model providing the microdosimetric framework which, when coupled with other appropriate physical mechanisms (spatial localisation of traps and recombination centres, competing centres in the recombination stage, variation in the capture cross section with temperature, etc) can be used to describe all the dominant features of the linear/supralinear behaviour of LiF:Mg,Ti.
Mediator analysis of passion for work in Indian millennials
Authors: Gulyani Gaatha , Bhatnagar Jyotsna
Published: February 2017

Purpose

The purpose of this paper is to examine the relationship between protean career attitude (PCA) and proactive work behaviors (PWB) and with the theoretical underpinning of self-determination theory to ascertain if passion for work acts as a mediator for PCA and PWB.

Design/methodology/approach

A survey of 255 millennial employees working in diverse industries in India (such as information technology, banking and education) was conducted. Regression analysis was used to measure the direct effects of the hypothesized relationships. Sobel test and bootstrapping analysis were used to measure the indirect effects of the hypothesized relationship.

Findings

PCA assists in fostering passion for work. Passion for work is positively related with PWB and fully mediates the relationship between PCA and PWB.

Practical implications

Employers should provide flexibility in work design and autonomy in career decisions. Also, Human resource managers should provide career growth opportunities to retain millennial talent.

Originality/value

This study bridges the knowledge gap between different domains of knowledge including PCA, passion for work and PWB. This study is one of the rare attempts to understand the relationship between PCA and PWB through the lens of passion for work. It also bridges the gap relating to its context. With an increasing number of millennials in workforce in India, an understanding of their career attitudes and outcome behaviors has become a significant concern. The results of the present study underpin career motivation theory, self-determination theory and generational cohort theory.
Evolution of financial reporting of life insurers
Authors: Jacob Rudolph A. , El-Gazzar Samir , McGregor Scott
Published: February 2017

Purpose

This paper aims to examine the capital market effects and predominance of unregulated embedded value (EV) financial reporting in the life insurance industry in foreign domestic markets, and US markets for foreign firms that cross-list in the USA.

Design/methodology/approach

Recent empirical archival data are analyzed and evaluated to determine the incremental and relative value relevance of an unregulated valuation metric that is disclosed by life insurers.

Findings

The findings support the proposition that EV is valuable supplemental information in foreign domestic markets, and in US markets for foreign life insurers that cross-list in the USA. Given that International Accounting Standards Board (IASB) and the Financial Accounting Standards Board (FASB) are engaged in projects to improve accounting standard for insurance companies, and have faced criticism with the existing drafts on this issue, the two institutions ought to consider the valuation relevance of EV disclosures. Moreover, this analysis strongly suggests that financial analysts in the USA should consider EV in valuing life insurers’ stocks.

Practical implications

The findings discussed in this paper are of special interest to financial reporting policy makers, financial analysts, firm compensation committees and managers, and academics.

Originality/value

This paper contributes to the extant literature by providing recent evidence that suggests that EV, an unregulated fair value market-driven metric, is more value-relevant than traditional earnings metrics such as earnings and book value. It is the only study that we are cognizant of that critically examines the recent empirical literature on this evolving issue.
The value relevance of intellectual capital disclosure: empirical evidence from Kuwait
Authors: Alfraih Mishari M.
Published: February 2017

Purpose

Drawing on market efficiency theory and studies on intellectual capital (IC) disclosure, this study aims to examine if IC information provided in the corporate annual reports of Kuwait Stock Exchange (KSE) listed companies in 2013 is value-relevant.

Design/methodology/approach

The analysis is divided into two parts. First, the level of intellectual capital disclosure (ICD) of KSE-listed companies is examined using the content analysis method. Second, the value relevance of financial reporting is examined empirically using Ohlson’s (1995) valuation model.

Findings

The results reveal that ICD is positively and significantly associated with market value, suggesting that greater ICD is valued by KSE market participants, who incorporate it into their valuation models.

Practical implications

Given the importance of ICD in enhancing equity valuation, a practical implication of this study is to make managers aware of its positive and significant effect on equity valuation, which may encourage companies to increase their level of disclosure.

Originality/value

This is the first study of the association between the level of ICD and the value relevance of financial reporting for market participants in Kuwait. It therefore extends and confirms the prior literature by broadening its scope to include frontier markets. Furthermore, it provides empirical evidence in support of recent calls from regulators and professional bodies for information that supplements and complements traditional financial reporting.
The theory and practice of integrative health care governance
Authors: Gauld Robin
Published: February 2017

Purpose

The purpose of this paper is to outline the theory and practice of governance for integrated care, using the case of New Zealand’s healthcare alliances.

Design/methodology/approach

This is descriptive analysis.

Findings

Alliance governance provides considerable scope for bringing health professional together to focus on whole system approaches to care design. As such, it facilitates care integration.

Research limitations/implications

This is a descriptive review.

Originality/value

Descriptions of alliance governance in New Zealand and in general are rare in the literature. This paper fills this gap.
Dermoscopic features of nail psoriasis treated with biologics
Authors: Hashimoto Yuki , Uyama Miki , Takada Yuko , Yoshida Kenji , Ishiko Akira
Published: February 2017

Although psoriatic nail lesions are small, they cause considerable discomfort for patients and adversely affect quality of life. Few studies have evaluated the dermoscopic features of psoriatic nails. The aim of this study was to clarify the dermoscopic features of nail psoriasis and identify those that reflect psoriatic activity. During biologic treatment of psoriasis, six patients with psoriatic nails twice underwent dermoscopic examination, with an interval of 17–42 weeks. We used the modified Nail Psoriasis Severity Index score and Psoriasis Area and Severity Index score to identify and assess dermoscopic features. We identified 10 dermoscopic findings, of which disappearance of diffuse scaling of the nail plate, transverse step‐like notches and splinter hemorrhages of the nail bed, and appearance of erythematous borders of the onycholytic area were associated with improvement in Psoriasis Area and Severity Index score. Dermoscopy can detect nail changes during psoriasis treatment and should be used to evaluate treatment success.
Economic Growth and Financial Statement Verification
Authors: LISOWSKY PETRO , MINNIS MICHAEL , SUTHERLAND ANDREW
Published: February 2017

We use a proprietary data set of financial statements collected by banks to examine whether economic growth is related to the use of financial statement verification in debt financing. Exploiting the distinct economic growth and contraction patterns of the construction industry over the years 2002–2011, our estimates reveal that banks reduced their collection of unqualified audited financial statements from construction firms at nearly twice the rate of firms in other industries during the housing boom period before 2008. This reduction was most severe in the regions that experienced the most significant construction growth. These trends reversed during the subsequent housing crisis in 2008–2011 when construction activity contracted. Moreover, using bank‐ and firm‐level data, we find a strong negative (positive) relation between audited financial statements during the growth period, and subsequent loan losses (construction firm survival) during the contraction period. Collectively, our results reveal that macroeconomic fluctuations produce temporal shifts in the overall level of financial statement verification and temporal shifts in verification are related to bank loan portfolio quality and borrower performance.