External Background Research Articles

Balanced ellipsoidal vortex equilibria in a background shear flow at finite Rossby number

We consider a uniform ellipsoid of potential vorticity (PV), where we exploit analytical solutions derived for a balanced model at the second order in the Rossby number, the next order to quasi-geostrophic (QG) theory, the so-called QG+1 model. We consider this vortex in the presence of an external background shear flow, acting as a proxy for the effect of external vortices. For the QG model the system depends on four parameters, the height-to-width aspect ratio of the vortex, $h/r$ , as well as three parameters characterising the background flow, the strain rate, $\gamma$ , the ratio of the background rotation rate to the strain, $\beta$ , and the angle from which the flow is applied, $\theta$ . However, the QG+1 model also depends on the PV, as well as the Prandtl ratio, $f/N$ ( $f$ and $N$ are the Coriolis and buoyancy frequencies, respectively). For QG and QG+1 we determine equilibria for different values of the background flow parameters for increasing values of the imposed strain rate up to the critical strain rate, $\gamma _c$ , beyond which equilibria do not exist. We also compute the linear stability of this vortex to second-order modes, determining the marginal strain $\gamma _m$ at which ellipsoidal instability erupts. The results show that for QG+1 the most resilient cyclonic ellipsoids are slightly prolate, while anticyclonic ellipsoids tend to be more oblate. The highest values of $\gamma _m$ occur as $\beta \to 1$ . For large values of $f/N$ , changes in the marginal strain rates occur, stabilising anticyclonic ellipsoids while destabilising cyclonic ellipsoids.

External background ionizing radiation and childhood cancer: Update of a nationwide cohort analysis

BackgroundExposure to high doses of ionizing radiation is known to cause cancer. Exposure during childhood is associated with a greater excess relative risk for leukemia and tumors of the central nervous system (CNS) than exposure in later life. Cancer risks associated with low-dose exposure (<100 mSv) are uncertain. We previously investigated the association between the incidence of childhood cancer and levels of exposure to external background radiation from terrestrial gamma and cosmic rays in Switzerland using data from a nationwide census-based cohort study. Here, we provide an update of that study using an extended follow-up period and an improved exposure model. MethodsWe included all children 0–15 years of age registered in the Swiss national censuses 1990, 2000, and 2010–2015. We identified incident cancer cases during 1990–2016 using probabilistic record linkage with the Swiss Childhood Cancer Registry. Exposure to terrestrial and cosmic radiation at children's place of residence was estimated using geographic exposure models based on aerial spectrometric gamma-ray measurements. We estimated and included the contribution from 137Cs deposition after the Chernobyl accident. We created a nested case-control sample and fitted conditional logistic regression models adjusting for sex, year of birth, neighborhood socioeconomic position, and modelled outdoor NO2 concentration. We also estimated the population attributable fraction for childhood cancer due to external background radiation. ResultsWe included 3,401,113 children and identified 3,137 incident cases of cancer, including 951 leukemia, 495 lymphoma, and 701 CNS tumor cases. Median follow-up in the cohort was 6.0 years (interquartile range: 4.3–10.1) and median cumulative exposure since birth was 8.2 mSv (range: 0–31.2). Hazard ratios per 1 mSv increase in cumulative dose of external background radiation were 1.04 (95% CI: 1.01–1.06) for all cancers combined, 1.06 (1.01–1.10) for leukemia, 1.03 (0.98–1.08) for lymphoma, and 1.06 (1.01–1.11) for CNS tumors. Adjustment for potential confounders had little effect on the results. Based on these results, the estimated population attributable fraction for leukemia and CNS tumors due to external background radiation was 32% (7–49%) and 34% (5–51%), respectively. ConclusionsOur results suggest that background ionizing radiation contributes to the risk of leukemia and CNS tumors in children.

Discovering Knowledge and Cognitive Based Drivers for SMEs Internationalization

Internationalisation begins with companies’ decision to enter global markets to develop knowledge and experience as key competitive factors in the global economy, which has been the subject of much empirical research. Decision-making, knowledge management, and effective internationalisation have become key strategic tools for all companies, especially for small- and medium-sized enterprises (SMEs). This study wants to provide a framework for SMEs internationalisation based on the real options theory, (ROT) as a knowledge driver method. For this purpose, the effective factors for internationalisation were identified by reviewing the literature on the subject and the internal and external backgrounds of the subject. Then, main and sub-factors were prioritised by the fuzzy analytic hierarchy process (AHP) method. The statistical population consisted of senior managers, business managers of SMEs in Isfahan, Iran, who were eligible to enter this study. Twenty-six experts participated in this study by judgmental non-random sampling method. A fuzzy AHP questionnaire was prepared in the form of 19 sub-factors and 7 main factors. The components of each factor in each group were also ranked by experts, and their weights were obtained. Next, according to the ROT strategies which have 5 options, an alignment matrix was used to align the factors affecting the decision with the strategies. After answering the research question, the option that had a higher mode was considered AS; then, this score was multiplied by the weight obtained in the previous step and the TAS was obtained. Finally, strategies were classified as appropriate, need further investigation, and inappropriate.

Spherically symmetric configuration in f(Q) gravity

General relativity can be formulated equivalently with a non-Riemannian geometry that associates with an affine connection of nonzero nonmetricity $Q$ but vanishing curvature $R$ and torsion $T$. Modification based on this description of gravity generates the $f(Q)$ gravity. In this work we explore the application of $f(Q)$ gravity to the spherically symmetric configurations. We discuss the gauge fixing and connections in this setting. We demonstrate the effects of $f(Q)$ by considering the external and internal solutions of compact stars. The external background solutions for any regular form of $f(Q)$ coincide with the corresponding solutions in general relativity, i.e., the Schwarzschild-de Sitter solution and the Reissner-Nordstr\"om-de Sitter solution with an electromagnetic field. For internal structure, with a simple model $f(Q)=Q+\alpha Q^2$ and a polytropic equation of state, we find that a negative modification ($\alpha<0$) provides support to more stellar masses while a positive one ($\alpha>0$) reduces the amount of matter of the star.

Low background measurement in CANDLES-III for studying the neutrinoless double beta decay of Ca48

We developed a CANDLES-III system to study the neutrino-less double beta (0$\nu\beta\beta$) decay of $^{48}$Ca. The proposed system employs 96 CaF$_{2}$ scintillation crystals (305 kg) with natural Ca ($^{\rm nat.}$Ca) isotope which corresponds 350\,g of $^{48}$Ca. External backgrounds were rejected using a 4$\pi$ active shield of a liquid scintillator surrounding the CaF$_2$ crystals. The internal backgrounds caused by the radioactive impurities within the CaF$_2$ crystals can be reduced effectively through analysis of the signal pulse shape. We analyzed the data obtained in the Kamioka underground for a live-time of 130.4\,days to evaluate the feasibility of the low background measurement with the CANDLES-III detector. Using Monte Carlo simulations, we estimated the background rate from the radioactive impurities in the CaF$_{2}$ crystals and the rate of high energy $\gamma$-rays caused by the (n, $\gamma$) reactions induced by environmental neutrons. The expected background rate was in a good agreement with the measured rate, i.e., approximately 10$^{-3}$ events/keV/yr/(kg of $^{\rm nat.}$Ca), in the 0$\nu\beta\beta$ window. In conclusion, the background candidates were estimated properly by comparing the measured energy spectrum with the background simulations. With this measurement method, we performed the first search for 0$\nu\beta\beta$ decay in a low background condition using a detector with a Ca isotope, in which the Ca present was not enriched, in a scale of hundreds of kg. The $^{48}$Ca isotope has a high potential for use in 0$\nu\beta\beta$ decay search, and is expected to be useful for the development of a next-generation detector for highly sensitive measurements.

Assessment of Ammunition Group Explosiveness in Destructive Effects Conditions and Ways to Reduce It

The ammunition placement in a small area creates the group explosion danger as a result of destructive effects. It is impossible to ensure the group explosive safety of ammunition, by increased distance between them, due to the limited volume in which they are placed. This can be achieved by using protective screens against the high-speed strikers impact. Another direction is the search for optimal ammunition placement schemes in storage that minimize the number of fragments falling into ammunition. The neutrons external background influence during the group storage of nuclear ammunition is also considered.

Numerical Study of AC Loss Characteristics in a Three-Phase Superconducting Induction Pump

The superconducting induction pump is a pumping system which moves electro-conductive liquid by using electromagnetism. It has the potential to be applied as the power system for the submarine propulsion and the pumping system for nuclear reactors. Since alternating current may generate more heat in the superconducting winding, it is extremely essential to analyze AC loss characteristics of the pumping system to avoid quenching phenomenon of superconducting tapes. In this article, a 2D-axisymmetric model of an annular linear induction pump which is composed of superconducting coils has been established by using T-A formulation. AC loss of superconducting coils under self-field and external alternating magnetic field have been studied. Meanwhile, the influence of some essential parameters such as the transmission current, coil turns have been analyzed as well. Results show that the arrangement position of coils in the pump plays an important role in determining the the AC loss of the superconducting winding. Meanwhile, self-field of the superconducting coils seems to have larger influence on the AC loss characteristics than the external alternating field. In conclusion, mechanism and relevant action laws of AC loss characteristics in the superconducting linear induction pump transported with three-phase alternating current and under the condition of external background AC field have been found in this article.

Monte Carlo simulation variance reduction techniques for photon transport in liquid xenon detectors

Monte Carlo simulations are a crucial tool for the analysis and prediction of various background components in liquid xenon (LXe) detectors. With improving shielding in new experiments, the simulation of external backgrounds, such as induced by gamma rays from detector materials, gets more computationally expensive. We introduce and validate an accelerated Monte Carlo simulation technique for photon transport in liquid xenon detectors. The method simulates photon-induced interactions within a defined geometry and energy range with high statistics while interactions outside of the region of interest are not simulated directly but are taken into account by means of probability weights. For a simulation of gamma-induced backgrounds in an exemplary detector geometry we achieve a three orders of magnitude acceleration compared to a standard simulation of a current ton-scale LXe dark matter experiment.

Вакуумное двулучепреломление в поле плоской электромагнитной волны

We study the process of vacuum birefringence in a strong electromagnetic field: a probe photon changes its polarization while traversing a counterpropagating laser beam. To describe this phenomenon, we calculate the polarization tensor in the field of a plane monochromatic wave to leading order with respect to its amplitude. The main goal of the study is to compare the results with the data obtained within the locally constant field approximation (LCFA). Here we identify the domain of the LCFA applicability in the case of a plane-wave external background. It is shown that the frequency of the probe photon and that of the external field are symmetrically involved in the relative uncertainty. The exact treatment of the spatiotemporal dependence beyond the LCFA becomes necessary at the energy scale 0.1-1 MeV.

Keyphrase extraction from single textual documents based on semantically defined background knowledge and co-occurrence graphs

The keyphrase extraction task is a fundamental and challenging task designed to extract a set of keyphrases from textual documents. Keyphrases are essential to assist publishers in indexing documents and readers in identifying the most relevant ones. They are short phrases composed of one or more terms used to represent a textual document and its main topics. In this article, we extend our research on C-Rank, which is an unsupervised approach that automatically extracts keyphrases from single documents. C-Rank uses concept-linking to link concepts in common between single documents and an external background knowledge base. We advance our study over C-Rank by evaluating it using different concept-linking approaches - Babelfy and DBPedia Spotlight. We evaluated C-Rank on data sets composed of academic articles, academic abstracts, and news articles. Our findings indicate that C-Rank achieves state-of-the-art results extracting keyphrases from scientific documents by experimentally comparing it to existing unsupervised approaches.

Keyphrase extraction from single textual documents based on semantically defined background knowledge and co-occurrence graphs

The keyphrase extraction task is a fundamental and challenging task designed to extract a set of keyphrases from textual documents. Keyphrases are essential to assist publishers in indexing documents and readers in identifying the most relevant ones. They are short phrases composed of one or more terms used to represent a textual document and its main topics. In this article, we extend our research on C-Rank, which is an unsupervised approach that automatically extracts keyphrases from single documents. C-Rank uses concept-linking to link concepts in common between single documents and an external background knowledge base. We advance our study over C-Rank by evaluating it using different concept-linking approaches - Babelfy and DBPedia Spotlight. We evaluated C-Rank on data sets composed of academic articles, academic abstracts, and news articles. Our findings indicate that C-Rank achieves state-of-the-art results extracting keyphrases from scientific documents by experimentally comparing it to existing unsupervised approaches.

STUDENT PERCEIVED EMPLOYABILITY WITH REFERENCE TO MEDIA STUDIES: VALIDATING A MODEL OF KEY DETERMINANTS

The motive of this research is to investigate the employability of media students. It aims to validate a holistic model of key determinants of perceived employability in the Indian context. These factors emerge from internal backgrounds such as academic performance, contacts, generic skills, and self-confidence of students; external backgrounds such as university role and labor market. Psychometric properties of the proposed scale were assessed including validation at exploratory and confirmatory level; reliability; convergent and discriminant validity. Further model fit estimates were demonstrated. The study results in a comprehensive model determining the perceived employability of media students. The practical implications of this study include the identification of the university‟s contribution to employability of students and providing a foundation for higher education policy formulation and amendments in the media studies program. The novelty of this study is validating the measurement tool for assessing the employability of media students in the Indian context. This study will contribute towards the improvement of the perceived employability of media students and the augmentation of literature in media studies.

SNO+ status and prospects

SNO+ is a multi-purpose experiment whose main goal is to study the nature of the neutrino mass through the observation of neutrinoless double-beta decay. Detection of this rare process would indicate that neutrinos are elementary Majorana particles, proving that lepton number is not conserved. The SNO+ detector will operate in three distinct phases with different target materials: water, pure liquid scintillator and tellurium-loaded liquid scintillator. During the water phase, the external backgrounds were confirmed to be within expectation, new limits on specific channels of invisible nucleon decay modes were set and the Boron-8 solar neutrino flux was measured and confirmed to be compatible with previous measurements. With a completed water phase, SNO+ is moving towards its main Tellurium-loaded phase. Here, we report the status of the experiment, the recent results and the potential of SNO+ for neutrinoless double-beta decay search.

Investigation of the effect of noise parameters of a 3D lidar on the error in estimating relief signatures of distant objects from 2D field intensity distributions of reflected radiation

We consider the influence of noise parameters of a 3D lidar and external background radiation on the error in estimating the relief signatures of distant objects from 2D field intensity distributions of the reflected radiation. A physical and mathematical model is developed to analyse the effect of noise. The dependence of the error in estimating the relief signatures at various signal-to-noise ratios is investigated taking into account the parameters of real multi-element photodetectors (MEPDs). The obtained results indicate the possibility of evaluating relief signatures of distant objects with high accuracy based on standard MEPDs simultaneously for a large number of points on the object’s surface with a signal-to-noise ratio of more than 4.

The Graph Reasoning Approach Based on the Dynamic Knowledge Auxiliary for Complex Fact Verification

Complex fact verification (FV) requires fusing scattered sequences and performing multi-hop reasoning over these composed sequences. Recently, by employing some FV models, knowledge is obtained from context to support the reasoning process based on pretrained models (e.g., BERT, XLNET), and this model outperforms previous out-of-the-art FV models. In practice, however, the limited training data cannot provide enough background knowledge for FV tasks. Once the background knowledge changed, the pretrained models’ parameters cannot be updated. Additionally, noise against common sense cannot be accurately filtered out due to the lack of necessary knowledge, which may have a negative impact on the reasoning progress. Furthermore, existing models often wrongly label the given claims as ‘not enough information’ due to the lack of necessary conceptual relationship between pieces of evidence. In the present study, a Dynamic Knowledge Auxiliary Graph Reasoning (DKAR) approach is proposed for incorporating external background knowledge in the current FV model, which explicitly identifies and fills the knowledge gaps between provided sources and the given claims, to enhance the reasoning ability of graph neural networks. Experiments show that DKAR put forward in this study can be combined with specific and discriminative knowledge to guide the FV system to successfully overcome the knowledge-gap challenges and achieve improvement in FV tasks. Furthermore, DKAR is adopted to complete the FV task on the Fake NewsNet dataset, showing outstanding advantages in a small sample and heterogeneous web text source.

Determinants of Entrepreneurial Intentions in University Graduating Students, Ethiopia An Empirical Review of Selected Papers

The purpose of this research was identifying the major determinant factors of entrepreneurial intention of university graduate student by reviewing 20 selected papers which were conducted in this area from the year 2013 up to 2019. on the base of theory of planed behavior the researcher identifies which factors were significantly affects entrepreneurship intentions. Easily available published papers were collected. Exploratory research design was implemented to identify the cross link effects of variables. Both qualitative and quantitative research approach was used to summarize and quantify the researchers finding. Secondary types of data were used to as source of data from 20 numbers of papers through critical review data collected. The research was employed both Descriptive and inferential statics techniques of data analysis. in the descriptive the result shows that analysis most researchers select attitude towards, entrepreneurship education, perceived social norms and perceived behavioral control as determinant variables. Finally study concludes that attitude toward entrepreneurship has significant positive impact on entrepreneurial intentions. subjective norms and perceived behavioral control have also significant positive influence and also entrepreneurship education External Environment personal background factor, locus of control, motivation for achievement and demographic characteristics have moderate positive influence on entrepreneurial intentions of graduate student in Ethiopia.

Состояние здоровья населения в районе расположения судоремонтного завода «Нерпа», осуществляющего работы по утилизации объекта ядерного наследия – плавучей технической базы «Лепсе»

Purpose: Purpose of this report is to assess the health status of the residents of the town of Snezhnogorsk, located in the impact area of the shipyard (SRZ Nerpa) involved in the decommission and dismantlement of the floating technical base Lepse (PTB Lepse).&#x0D; Material and method: The following parameters were assessed as public health indicators: total primary and chronic primary morbidity of adult and children population, child disability, reproductive health in terms of the status of pregnant women and newborns, general and child mortality. Annual external radiation background values were evaluated along with contents in soil and water of manmade radionuclides, such as 137Cs and 90Sr, and natural ones, such as 226Ra, 223Th, 40K and 235U.&#x0D; Results: The health of the population of the town of Snezhnogorsk, being measured by incidence indicators and reproductive health, is lower than that in the country as a whole: the adult morbidity (667.7 ± 4.2 and 454.2 ± 19.8 per 1000 residents respectively) and child morbidity (3336.2 and 2052.3 ± 194.4 per 1000 residents respectively) is higher; the frequency of adverse pregnancy outcomes (stillbirth, early neonatal fetal death, spontaneous abortions) is also higher – 86.2 ± 18.4 and 46.6 per 1000 residents respectively.&#x0D; Conclusion: The main causes of the negative impact on the health of the population of the town of Snezhnogorsk are climatic and geographical conditions of the Kola Arctic and the presence of medium-light iodine deficiency (goiter endemia).

Calibration of a Tri-Band Microwave Radiometric System with Background Noise Compensation

It is shown that for microwave radiometric systems for remote sensing of natural environments, the issue of unambiguous determination of the correspondence of the output signal to the value of the radio brightness temperature of the probed region, from which the physical parameters are estimated, is important. Microwave radiometric systems operate under external noise and background noise. This article explores the effect of background noise on the external calibration of a microwave radiometric system using an external “deterministic” noise signal source. The conditions for performing calibration in a system with compensation for the influence of background noise are analyzed. The analysis of the output signal of the microwave radiometric system showed a significant effect of background noise on the parameter that determines the reference origin of the receiver scale. The possibility of reducing the interference effect of background noise on the measurement results in a microwave radiometric system with a two-channel antenna operating on two modes of a circular waveguide is considered. It is shown that an additional compensation signal is formed at the antenna output. An analytical assessment of the degree of compensation of the influence of background noise on the output difference signal of the system is carried out. We perform a numerical analysis of the error of external calibration of a three-band microwave radiometric system with compensation of background noise when receiving thermal radiation to a common aperture of the antenna.

Revealing Postcolonialism through Unrelated Words Translation Strategy in Translating Toer’s Bumi Manusia into Lane’s This Earth Of Mankind

The fast development of translation field entails transferring one culture to another culture. Linguistic elements and the message of a writing, the external background such as culture, political, economic, or even historical background that adheres to the Source Text (ST) inevitably has to be taken to the Target Text (TT). In order to produce an acceptable product of literary translation, a translator has to possess knowledge of Source Text background. This research is aimed at finding out the ideology in unrelated words’ translation strategy in translating Toer’s Bumi Manusia, a winner of PEN Freedom-to-write Awards in 1988 and Ramon Magsaysay Awards in 1995. This novel shows a truthful depiction of what happened back then in Indonesia and the values that were struggled for the society. This novel is translated into This Earth of Mankind. This research gives a perspective regarding postcolonial translation in a way that it reveals the ideology and scope of postcolonialism by observing and understanding unrelated words’ translation strategy. Revealing postcolonialism in This Earth of Mankind is done through translation using unrelated words as the concept expressed by the source item is not lexicalized at all in English in the light of postcolonial translation approach. The findings of translation of the postcolonial novel into English show a great deal in meaning and context alteration, the loss of information, the less impact in reading and interpreting the text, and generalization which universalizes the unique and great Javanese culture as the main setting of the story Bumi Manusia. Translation using unrelated words reveals neo-colonialism which unfortunately still dominates through the work of translation.

Markov-Modulated Linear Regression Parameter Estimation Using a Convolution of Exponential Densities

Markov-modulated linear regression model is a special case of the Markov-additive process (𝒀, 𝑱) = {(𝒀(𝒕), 𝑱(𝒕)), 𝒕 ≥ 𝟎}, where component J is called Markov, and component Y is additive and described by a linear regression. The component J is a continuous-time homogeneous irreducible Markov chain with the known transition intensities between the states. Usually this Markov component is called the external environment or background process. Unknown regression coefficients depend on external environment state, but regressors remain constant. This research considers the case, when the Markov property is not satisfied, namely, the sojourn time in each state is not exponentially distributed. Estimation procedure for unknown model parameters is described when it’s possible to represent transition intensities as a convolution of exponential densities. An efficiency of such an approach is evaluated by a simulation.