Miracle-dz/UniFAR-FTUs huggingface dataset:
Formation of Massive Black Holes in Dense Star Clusters. I. Mass Segregation and Core Collapse

We study the early dynamical evolution of young dense star clusters by using Monte Carlo simulations for systems with up to N = 107 stars. Rapid mass segregation of massive main-sequence stars and the development of the Spitzer instability can drive these systems to core collapse in a small fraction of the initial half-mass relaxation time. If the core-collapse time is less than the lifetime of the massive stars, all stars in the collapsing core may then undergo a runaway collision process leading to the formation of a massive black hole. Here we study in detail the first step in this process, up to the occurrence of core collapse. We have performed about 100 simulations for clusters with a wide variety of initial conditions, varying systematically the cluster density profile, stellar initial mass function (IMF), and number of stars. We also considered the effects of initial mass segregation and stellar evolution mass loss. Our results show that, for clusters with a moderate initial central concentration and any realistic IMF, the ratio of core-collapse time to initial half-mass relaxation time is typically ~0.1, in agreement with the value previously found by direct N-body simulations for much smaller systems. Models with even higher central concentration initially, or with initial mass segregation (from star formation) have even shorter core collapse times. Remarkably, we find that, for all realistic initial conditions, the mass of the collapsing core is always close to ~10-3 of the total cluster mass, very similar to the observed correlation between central black hole mass and total cluster mass in a variety of environments. We discuss the implications of our results for the formation of intermediate-mass black holes in globular clusters and super star clusters, ultraluminous X-ray sources, and seed black holes in proto-galactic nuclei.
Serum Electrolytes During Different Phases Of Menstrual Cycle

Background: Although the coordinated sequence of hormonal changes during the normal menstrual cycle are well characterized, whether similar or parallel changes occur in the distribution of various electrolytes has not been clearly established. Materials and methods: This corollary follow up study on 50 healthy normal menstruating females presents variation in serum calcium, magnesium, sodium and potassium during menstrual, follicular and luteal phases of menstrual cycle. Results: The study demonstrated that serum calcium levels were significantly (p < 0.001) higher in follicular phase than menstrual and luteal phases. Serum magnesium levels were significantly (p < 0.001) lower in follicular phase than menstrual and luteal phases. Serum sodium levels were significantly lower in luteal phase than the menstrual and follicular phases. Serum potassium levels were higher (non-significant) in luteal phase than menstrual and follicular phases. Conclusion: The concurrence of these cyclical changes in these electrolytes supports the claim of many women that they suffer changes in fluid and electrolyte balance in the premenstrual days. Moreover, these changes may have significance in terms of the normal reference interval, hence necessitate small but significant alterations to the normal reference interval.
Effect on nitrate concentration in stream water of agricultural practices in small catchments in Brittany: II. Temporal variations and mixing processes

Abstract. In catchments with impervious bedrock, the nitrate concentrations in streamwater often show marked seasonal and small inter-annual variations. The inter-annual trends are usually attributed to changes in nitrogen inputs, due to changes in land use or in nitrogen deposition whereas seasonal patterns are explained in terms of availability of soil nitrate for leaching and of seasonality of nitrogen biotransformations. The companion paper showed that inter-annual variations of nitrogen in streamwater are not directly related to the variations of land use. The aim of this study is to describe nitrate concentration variations in a set of very small adjacent catchments, and to discuss the origin of the inter-annual and seasonal trends. Data from four catchments at the Kerbernez site (South Western Brittany, France) were used in this study. Nitrate concentrations in streamwater were monitored for eight years (1992 to 1999) at the outlet of the catchments. They exhibit contrasting inter-annual and seasonal patterns. An extensive survey of agricultural practices during this period allowed assessment of the amount of nitrogen available for leaching. The discharges measured since 1997 show similar specific fluxes but very different seasonal dynamics between the catchments. A simple, lumped linear store model is proposed as an initial explanation of the differences in discharge and nitrate concentration patterns between the catchments. The base flow at the outlet of each catchment is considered as a mixture of water from two linear reservoirs with different time constants. Each reservoir comprises two water stores, one mobile contributing to discharge, the other, immobile, where nitrate moves only by diffusion. The storm flow, which accounts for less than 10% of the annual flux, is not considered here. Six parameters were adjusted for each catchment to fit the observed data: the proportion of deep losses of water, the proportion of the two reservoirs and the size and initial concentration of the two immobile stores. The model simulates the discharge and nitrate concentration dynamics well. It suggests that the groundwater store plays a very important role in the control of nitrate concentration in streamwater, and that the pattern of the seasonal variation of nitrate concentration may result from the long term evolution of nitrogen losses by leaching. Keywords: nitrate, diffuse pollution, groundwater, seasonal variations, agricultural catchment, simulation model
Does Perceived Ease of Use Mitigate Computer Anxiety and Stimulate Self-Regulated Learning for Pre-Service Teacher Students?.

The aim of this study is to contribute to a better understanding of challenges and factors which influence learning efficiency with electronic-portfolios. Based on the Technology Acceptance Model (TAM; Davis, Bagozzi, & Warshaw, 1989) we analyzed external variables (e.g., computer-anxiety) that influence technology acceptance and the actual system use in form of self-regulated learning. Additionally we included computer related attitudes and correlated them with external variables as well as measures of self-regulated learning. To foster learning efficacy with electronic portfolios the program Microsoft OneNote was used. A group of N = 32 preservice teachers worked on an electronic-portfolio in OneNote for 14 weeks. Results showed that computer-anxiety and the challenge of working with an electronic portfolio decreased over time. The more the computer was rated as a useful tool for learning and teaching, the less computer-anxiety, the more challenge and interest and better mood students reported. In contrast the more the computer was seen as uninfluential tool for working and learning, the more computer anxiety, hopelessness, anxiety and less positive mood, interest and joy to work on the electronic-portfolio has been reported. So, students’ computer related attitudes should be considered when working with an electronic-portfolio to better tailor instruction to learner needs.
Proposed Hybrid Color Histogram based Obstacle Detection Technique

Assistive innovations for visually impaired persons are demonstrating a quick development, letting valuable devices to bolster their everyday exercises, therefore enhancing social consideration. This paper intends to propose a technique for helping blind persons in detecting obstacles in their path. Keypoint matching is an imperative feature of Computer vision obstacle detection. In this paper two techniques QC-LBP (Quantized Color based LBP) & QC-CSLBP (Quantized color based CS-LBP) are proposed based on hybrid features of LBP/CS-LBP, Gabor & HSV color Histograms. Then, these are compared to the already existing techniques such as SIFT, hybrid of SIFT with LBP & Gabor Filter. We grasp CS-LBP into our system due to its computational effectiveness & LBP due to its state-of-art execution in various issues. Gabor filter is coupled into our system due to its invariant nature. Color of each image is extracted using HSV, which on splitting undergoes different quantization levels & respective histograms are obtained. These obtained histograms are compared based on chi-square distance & matching object is obtained. In this paper, we present framework for detecting obstacles in the way of blind persons & also compare its efficiency with various existing algorithms. The output of the proposed system is the shape of obstacle or object in front of the blind user, which is intimated to the user in the form of sound. We show that our framework outperforms the other existing techniques.
Hysteresis of Spectral Evolution in the Soft State of Black Hole Binary LMC X-3

We report the discovery of hysteresis between the X-ray spectrum and luminosity of black hole binary LMC X-3. Our observations, made with the Proportional Counter Array on the Rossi X-Ray Timing Explorer, took place entirely within the soft spectral state, which was dominated by a spectral component that was fitted well with a multicolor disk blackbody. A power-law component was seen only during times when the luminosity of the disk blackbody was declining. The X-ray luminosity at these times was comparable to that seen in transient systems (X-ray novae) when they return to the hard state at the end of an outburst. Our observations may represent partial transitions to the hard state; complete transitions have been seen in this system by Wilms and coworkers. If they are related to the soft-to-hard transition in transients, then they demonstrate that hysteresis effects can appear without a full state transition. We discuss these observations in the context of earlier observations of hysteresis within the hard state of binaries 1E 1740.7-2942 and GRS 1758-258 and in relation to published explanations of hysteresis in transients.
Flight Trials of a Rotorcraft Unmanned Aerial Vehicle Landing Autonomously at Unprepared Sites

ABSTRACT This paper describes the flight testing and evaluation of technologies for the autonomous landing of a Yamaha RMAX helicopter at non-cooperative sites without the aid of GPS. The Yamaha RMAX used for these flight trials has been modified to include stereo cameras, a scanning laser, and an avionics payload. Machine vision stereo range mapping is used to generate an accurate terrain representation, and a safe landing area determination algorithm is used to select the safest landing point within the terrain. A machine vision self-localization system is used to measure the helicopter position during the descent and landing when GPS is unavailable. The software and hardware architecture of the flight system is presented and each system component is described. Results and lessons learned from the flight evaluation and optimization of the individual components are reported as well as the overall system performance with respect to a set of objective metrics for the autonomous landing flight trails.
Configurations of human resource management practices: a model and test of internal fit

This study examined human resource management (HRM) configurations. A typology consisting of four bundles of aligned HRM practices (labelled the bureaucratic, market, professional and flexibility bundle) linked to organizational structures was developed. Support for the proposed ideal-typical bundles was found in an assessment by a panel of experts. Next, the distance between the ideal types and actual bundles of HR practices was assessed for 175 organizations. For each, senior HR managers' ratings of HRM practices and CEO ratings of outcomes were obtained. Support was found for two of the four proposed types and about one-third of the firms showed some fit with one of these two types. The ‘fit in general hypothesis’ (i.e. the closer an observed HR bundle resembles any of the ideal types, the higher organizational performance) did not receive support. However, fit with a specific type of bundle (the professional bundle) did relate positively to outcomes. Organizations with observed HRM practices fitting the professional bundle score significantly higher on measures of firm performance, employees' going beyond contract, and firm innovativeness.
AN APPRAISAL ANALYSIS OF CRITICAL REVIEWS WRITTEN BY UNDERGRADUATE STUDENTS OF ENGLISH LANGUAGE EDUCATION

This paper discusses the analysis of evaluative language (or, appraisal) in students‘ writing production. The data were taken from a group of undergraduate students in a Genre-Based Writing course in the English Department at a state university in Semarang, Central Java. The focus of the study is at the use of appraisal in the students‘ critical reviews of a conference paper. Appraisal refers to the choice of words, phrases, and structures used by speakers or writers to reveal their stance, thinking, and feelings on an issue. Situated in Systemic Functional Linguistics and a genrebased approach, the aim of the paper is two fold: Firstly, to analyse how the students organize their critical reviews in terms of generic structure. Secondly, to analyse what appraisal resources used by the students in their critical reviews. In the data analysis, the organization of the texts is examined by using a critical review template suggested by Thomson Rivers University Writing Center, as the template is not only helpful but also practical for English language learners, and the use of appraisal is analysed using the appraisal theory developed by Martin and White (2005). The finding shows that almost all the students organized their texts following the generic structure of a critical review. It also shows that the students use appraising items which dominantly indicate their appreciation (attitude), proclaim (engagement), and force (graduation). Finally, this paper discusses some pedagogical significance of this study on the teaching of writing; in particular in developing students‘ voice on critical reviews.
When it Pays to Be Friendly: Employment Relationships and Emotional Labour in Hairstyling

This article examines worker-client relationships in hairstyling. Data are drawn from interviews with 15 hourly-paid and 32 self-employed hairstylists and a self-administered survey. Relations of employment are found to be central to the deployment of emotional labour. Self-employed owner-operators are highly dependent on clients, rely on deep-acting, enact favours, and are prone to emotional breaking points when they fail to realise their ‘congealed service’. In contrast, hourly-paid stylists perform surface acting, resist unpaid favours and experience fewer breaking points. Methodologically this article demonstrates the importance of comparative employment relations analysis (CERA) for exposing the relationship between employment structures and labour process experiences.
Comparison of speech-based in-car HMI concepts in a driving simulation study

This paper reports experimental results from a driving simulation study in order to compare different speech-based in-car human-machine interface concepts. The effects of the use of a command-based and a conversational in-car speech dialog system on usability and driver distraction are evaluated. Different graphical user interface concepts have been designed in order to investigate their potential supportive or distracting effects. The results show that only few differences concerning speech dialog quality were found when comparing the speech dialog strategies. The command-based dialog was slightly better accepted than the conversational dialog, which can be attributed to the limited performance of the system's language understanding component. No differences in driver distraction were revealed. Moreover, the study revealed that speech dialog systems without graphical user interface were accepted by participants in the driving environment and that the use of a graphical user interface impaired the driving performance and increased gaze-based distraction. In the driving scenario, the choice of speech dialog strategies does not have a strong influence on usability and no influence on driver distraction. Instead, when designing the graphical user interface of an in-car speech dialog systems, developers should consider reducing the content presented on the display device in order to reduce driver distraction.
Tag read enhancement using unsynchronized signal from adjacent readers in multi-cell RFID system

This paper addresses the interference issue in a passive multi-cell radio frequency identification (RFID) system. Instead of considering the negative effect of interfering RF signals from adjacent readers, we investigate its constructive effect in providing extra RF power to tags in the cell of the desired reader system. Through detailed simulation and experimental analysis, it is found that the unsynchronised signal from neighbouring readers can be utilized to activate marginal tags through enhancing power delivery. This results in improved tag received signal strength indicator (RSSI). In addition, it is found that the overlap zone between two RFID cells is not as vulnerable to interference as one might think. In fact, the adjacent reader may facilitate the desired reader to read more tags in the overlapping zone, although a longer inventory period may be required. We believe these findings might provide a new insight into the interference effect on multi-cell RFID system and be applied to future medium access control (MAC) protocols.
Military Justice: Case Processing and Sentencing Decisions in America’s “Other” Criminal Courts

A wealth of criminological research examines punishment outcomes in state and federal courts, but virtually no research examines the thousands of defendants punished in the military justice system each year. Military courts are characterized by unique case processing norms and distinctive socio-cultural influences that shape punitive decision-making in key ways. The current study provides a broad, systematic analysis of the correlates of criminal case processing in this rarely examined court context. It analyzes a large sample of Air Force court-martial cases, evaluating the evidence for gender and racial/ethnic disparities and the influence of military-specific considerations. Findings indicate that some factors, like offense seriousness, exert influences that are largely consistent with the civilian court literature, but others including gender, race/ethnicity and case processing decisions operate in ways that are particular to military courts. Results are interpreted in light of contemporary sentencing theoretical perspectives.
Differential contributions of ApoE4 and female sex to BACE1 activity and expression mediate Aβ deposition and learning and memory in mouse models of Alzheimer’s disease

Alzheimer’s disease (AD), the most common form of dementia, disproportionately affects women in both prevalence and severity. This increased vulnerability to AD in women is strongly associated with age-related ovarian hormone loss and apolipoprotein E 4 allele (ApoE4), the most important genetic risk factor for sporadic AD. Up to date, the mechanism involved in the interaction between ApoE4 and sex/gender in AD is still unclear. This study evaluated the sex-dependent ApoE4 effects on learning and memory, Aβ deposition and potential mechanisms, using mice bearing both sporadic (ApoE4) and familial (APPSwe, PS1M146V, tauP301L; 3xTg) AD risk factors and compared with sex- and age-matched 3xTg or nonTg mice. Compared to nonTg mice, transgenic mice of both sexes showed spatial learning and memory deficits in the radial arm water maze and novel arm discrimination tests at 20 months of age. However, at 10 months, only ApoE4/3xTg mice showed significant learning and memory impairment. Moreover, molecular studies of hippocampal tissue revealed significantly higher protein levels of Aβ species, β-site APP cleavage enzyme (BACE1) and Sp1, a transcription factor of BACE1, in female ApoE4/3xTg when compared with female nonTg, female 3xTg, and male ApoE4/3xTg mice. Significantly increased BACE1 enzymatic activities were observed in both male and female mice carrying ApoE4; however, only the females showed significant higher BACE1 expressions. Together, these data suggest that ApoE4 allele is associated with increased BACE1 enzymatic activity, while female sex plays an important role in increasing BACE1 expression. The combination of both provides a molecular basis for high Aβ pathology and the resultant hippocampus-dependent learning and memory deficits in female ApoE4 carriers.
A Reliable Radiometric Assay for the Determination of Angiotensin I-Converting Enzyme Activity in Urine

We present a radiometric assay for the determination of urinary angiotensin-converting enzyme activity, using benzoyl-[1-14C]glycyl-L-histidyl-L-leucine as the substrate. An optimal pH of 8.3, an optimal chloride concentration of 0.375 mol/l and complete inhibition by EDTA-Na2, captopril and enalaprilat confirm the specificity of the assay. Comparison of dialysis and ultrafiltration for concentration of urine showed the existence of angiotensin-converting enzyme inhibitors in human urine. Dialysis against water was the more effective method for avoiding enzyme inhibition. After dialysis of urine, the assay was linear with time and with enzyme concentration; it was highly sensitive (60 mU/l) and showed good reproducibility. Under our technical conditions, we found angiotensin-converting enzyme activity in urine samples with quantitatively abnormal protein contents, but not in normal urine. Urinary angiotensin-converting enzyme did not correlate with proteinuria nor with water-salt parameters or creatinine. We confirm the kidney tubular epithelial origin of the enzyme, and propose the use of our assay to study urinary angiotensin-converting enzyme as a marker of renal tubular damage.
Seroprevalence of Turkey Coronavirus in North American Turkeys Determined by a Newly Developed Enzyme-Linked Immunosorbent Assay Based on Recombinant Antigen

ABSTRACT Turkey coronavirus (TCoV) causes diarrhea in young turkey poults, but little is known about its prevalence in the field. To address this, the complete nucleocapsid gene was cloned and expressed in Escherichia coli. Expressed nucleocapsid gene produced two distinct proteins (52 and 43 kDa); their specificity was confirmed by Western blotting using two different monoclonal antibodies. Recombinant N protein was purified and used as an antigen to develop an enzyme-linked immunosorbent assay (ELISA) for the serological detection of TCoV that was then validated using experimentally derived turkey serum. The N-based ELISA showed (97%) sensitivity and (93%) specificity for TCoV, which was significantly higher than an infectious bronchitis coronavirus-based commercial test for TCoV. To assess the utility of this recombinant ELISA, 360 serum samples from turkey farms in Ontario, Canada, and 81 serum samples from farms in Arkansas were tested for TCoV-specific antibodies. A high seroprevalence of TCoV was found in turkeys from the Ontario farms with 73.9% of breeders and 60.0% of meat turkeys testing seropositive using the N-based ELISA. Similarly, a high field prevalence was found in the turkeys from Arkansas, for which 64.2% of the serum samples tested seropositive.