1,973 research outputs found
Spectral modeling of type II supernovae. I. Dilution factors
We present substantial extensions to the Monte Carlo radiative transfer code
TARDIS to perform spectral synthesis for type II supernovae. By incorporating a
non-LTE ionization and excitation treatment for hydrogen, a full account of
free-free and bound-free processes, a self-consistent determination of the
thermal state and by improving the handling of relativistic effects, the
improved code version includes the necessary physics to perform spectral
synthesis for type II supernovae to high precision as required for the reliable
inference of supernova properties. We demonstrate the capabilities of the
extended version of TARDIS by calculating synthetic spectra for the
prototypical type II supernova SN1999em and by deriving a new and independent
set of dilution factors for the expanding photosphere method. We have
investigated in detail the dependence of the dilution factors on photospheric
properties and, for the first time, on changes in metallicity. We also compare
our results with two previously published sets of dilution factors by Eastman
et al. (1996) and by Dessart & Hillier (2005), and discuss the potential
sources of the discrepancies between studies.Comment: 16 pages, 12 figures, 2 tables, accepted for publication in A&
Properdin and factor H: Opposing players on the alternative complement pathway "see-saw"
This article has been made available through the Brunel Open Access Publishing Fund.Properdin and factor H are two key regulatory proteins having opposite functions in the alternative complement pathway. Properdin up-regulates the alternative pathway by stabilizing the C3bBb complex, whereas factor H downregulates the pathway by promoting proteolytic degradation of C3b. While factor H is mainly produced in the liver, there are several extrahepatic sources. In addition to the liver, factor H is also synthesized in fetal tubuli, keratinocytes, skin fibroblasts, ocular tissue, adipose tissue, brain, lungs, heart, spleen, pancreas, kidney, muscle, and placenta. Neutrophils are the major source of properdin, and it is also produced by monocytes, T cells and bone marrow progenitor cell line. Properdin is released by neutrophils from intracellular stores following stimulation by N-formyl-methionine-leucine-phenylalanine (fMLP) and tumor necrosis factor alpha (TNF-α). The HEP G2 cells derived from human liver has been found to produce functional properdin. Endothelial cells also produce properdin when induced by shear stress, thus is a physiological source for plasma properdin. The diverse range of extrahepatic sites for synthesis of these two complement regulators suggests the importance and need for local availability of the proteins. Here, we discuss the significance of the local synthesis of properdin and factor H. This assumes greater importance in view of recently identified unexpected and novel roles of properdin and factor H that are potentially independent of their involvement in complement regulation
Relationship between leadership style and project success among IT Professionals in Nigeria: Implications to Project Management
The aim of the study is to examine the relationship between leadership style of IT Professionals and IT project success in Nigeria. A total of 150 questionnaires were distributed to IT professionals in Nigeria, and a total of 59 completed questionnaires were received resulting in a total of 39.3% response rate. The findings of the study indicate that there is a positive relationship between project manager’s leadership styles and IT projects success in Nigeria. In other words the leadership behavior of IT project manager results in project success in varying degrees based on the type of style exhibited. The result also indicated that the IT project managers in our sample exhibited more of transformational than any other styles investigated
Analytical approximations to numerical solutions of theoretical emission measure distributions
Emission line fluxes from cool stars are widely used to establish an apparent
emission measure distribution, Emd-app(Te), between temperatures characteristic
of the low transition region and the low corona. The true emission measure
distribution, Emd-t(Te), is determined by the energy balance and geometry
adopted and, with a numerical model, can be used to predict Emd-app(Te), to
guide further modelling. The scaling laws that exist between coronal parameters
arise from the dimensions of the terms in the energy balance equation. Here,
analytical approximations to numerical solutions for Emd-t(Te) are presented,
which show how the constants in the coronal scaling laws are determined. The
apparent emission measure distributions show a minimum value at some
temperature (T0) and a maximum at the mean coronal temperature Tc (although in
some stars, emission from active regions can contribute). It is shown that, for
the energy balance and geometry adopted, the analytical values of the emission
measure and electron pressure at T0 and Tc, depend on only three parameters:
the stellar surface gravity and the values of T0 and Tc. The results are tested
against full numerical solutions for Epsilon Eri (K2 V) and are applied to
Procyon (alpha CMi; F5 IV/V). The analytical approximations can be used to
restrict the required range of full numerical solutions, to check the assumed
geometry and to show where the adopted energy balance may not be appropriate.Comment: 9 pages, accepted by MNRA
Perception of Research Culture among Undergraduate Students in a Malaysian Public University
Studies on research culture often focus on how administrators and academics inculcate this culture and what impact it has on undergraduates. Evidently, literature information on undergraduates’ perception of university research and publication agenda is lacking. Considering the fact that the campus community comprises largely of an undergraduate population and their activities, facts and conjectures alluding to research culture can be misleading without the views of undergraduate students. The study investigated the perception of research culture among undergraduate students in a Malaysian public university. The objectives of the study were to examine the students’ awareness of the research culture of the university, ranging from the research culture of the university as per the lecturers to the research reputation of the university. A survey was carried out using questionnaires incorporated within the e-learning platform (Morpheus) of a taught course on scientific communication. The analysis of questionnaire data from 56 students showed that undergraduates are more aware of research than publication matters. They do not think that good research correlates with better teaching. Local students are also indifferent to issues of university ranking. Our findings provide the basis for rethinking and deriving more accurate explanations of research culture appreciation in local public universities
Lower-limb injury in elite Australian football: A narrative review of kinanthropometric and physical risk factors
Objective
This review aims to provide a succinct and critical analysis of the current physical and mechanical demands of elite Australian football while examining lower-limb injury and the associated physical and kinanthropometric risk factors.
Methods
MEDLINE, PubMed, Web of Science and SPORTSDiscus electronic databases were searched for studies that investigated the playing demands, injury trends, and physical and kinanthropometric injury risk factors of elite Australian football. Articles from similar team sports including soccer and rugby (union and league) were also included.
Results
While the physical demands of elite AF have steadied over the past decade, injury rates continue to rise with more than two-thirds of all injuries affecting the lower-limbs. Body composition and musculoskeletal morphological assessments are regularly adopted in many sporting settings with current research suggesting high and low body mass are both associated with heightened injury risk. However, more extensive investigations are required to determine whether the proportions of muscle and fat are linked. Repeated assessment of musculoskeletal morphology may also provide further insight into stress fracture rates.
Conclusions
While kinanthropometric and physical attributes are highly valued within elite sporting environments, establishing a deeper connection with injury may provide practitioners with more insight into current injury trends
Law and the Body in Joseon Korea: Statecraft and the Negotiation of Ideology
Once considered almost exclusively to be the domain of legal scholars, Joseon dynasty criminal law is recently attracting increasing attention from social, political and intellectual historians of Korea. Despite often reaching opposing conclusions on the characteristics of Joseon legal culture, historians and legal scholars share a strong focus on the dominating role of Confucian ideology. While acknowledging the importance of Confucianism for Joseon statecraft, this paper argues that in actual statecraft and the application of the law, this ideology was negotiated with the perceived needs of the state. The focus of analysis is the relationship between the judicial process—investigation, interrogation and punishment—and cosmological, ideological and cultural notions related to the body. The purpose is to show the tension between the state need to maintain the system and uphold social order (as defined by the state) and the need for the state itself to adhere to the basic principles of the ideology that underpinned this system. Addressing the role of law and punishment in statecraft, the analysis is based on a theoretical framework that combines a conflict-based understanding of society with one that is consensus-based. While on the one hand the violation of notions related to the body was the purport of punishment when dealing with the most severe crimes against the state and its ideology, we can also see how such notions influenced the discourses on penal benevolence, torture and exhumation, whilst partly constituting the reason why some forms of torture were prohibited
Characterising lower-body musculoskeletal morphology and whole-body composition of elite female and male Australian Football players
Background: Physical demands and injury rates differ between elite female and male Australian Football (AF) players. To improve understanding of contributing physical factors to these differences, the purpose of this study was to investigate lower-body morphology and whole-body composition of elite footballers competing in the Australian Football League (AFL) and Australian Football League Women’s (AFLW). Methods: Lower-body morphology and whole-body composition of 23 AFL players and 23 AFLW players were assessed using peripheral Quantitative Computed Tomography and Dual-energy X-ray Absorptiometry at the beginning of pre-season. Differences between cohorts, with sub-analyses of kicking vs. support limbs, and experienced vs. inexperienced player status were assessed using two-sample independent t-tests. Magnitude of differences were assessed using Cohen’s d effect sizes. Results: AFL players had greater absolute (p \u3c 0.001; ES = 3.28) and relative (p \u3c 0.001; ES = 2.29) whole body lean soft-tissue mass, with less absolute (p = 0.004; ES = 0.91) and relative (p \u3c 0.001; ES = 2.29) fat mass than AFLW players. For AFLW players, no significant differences existed between kicking and support limbs with few differences observed between experienced and inexperienced players. Conclusions: Greater emphasis on physical development in AFLW players may be required to enable increases in muscle mass and skeletal robustness, to ensure they can tolerate the loads of elite competition
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