Miracle-dz/UniFAR-FTUs huggingface dataset:
Numerical Investigation of Shocks in Compressible Turbulent Temporal Mixing Layers with Large Eddy Simulation

In this paper, the results of three-dimensional numerical simulation of compressible turbulent temporal mixing layers are presented for a high Mach number (M=1.4) using Large Eddy Simulation (LES). The purpose of this study is developing LES in compressible turbulent temporal mixing layers in supersonic flows. Initially, we derive the filtered Navier-Stokes equations using the top-hat filtering function. Subsequently, the small scale motions are modeled by a dynamic eddy- viscosity subgrid-scale model. Compressible LES not only require the modeling of the subgrid-terms in the momentum equation, but also the modeling of the subgrid-terms in the energy equation which play the main role at higher Mach numbers. Two prominent parameters in mixing layers are vorticity thickness and momentum thickness . The results of these two parameters have been compared with the results of the Direct Numerical Simulation (DNS). The LES results correspond very well to the DNS results. Finally, we consider the shocks that occur in the supersonic mixing layers at M=1.4 using LES. In addition, we will study the physical nature and origin of these shocks. Different types of turbulent vortices that generate the shocks have been identified: a vortex which accelerates fluid along its axis and a pair of counter rotating vortices.
Astrophysical properties of star clusters in the Magellanic Clouds homogeneously estimated by ASteCA

Fil: Perren, Gabriel Ignacio. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - La Plata. Instituto de Astrofisica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronomicas y Geofisicas. Instituto de Astrofisica La Plata; Argentina
A Deep X-Ray View of the Synchrotron-dominated Supernova Remnant G330.2+1.0

We present moderately deep (125 ks) XMM-Newton observations of supernova remnant G330.2+1.0. This remnant is one of only a few known that fall into the “synchrotron-dominated” category, with the emission almost entirely dominated by a nonthermal continuum. Previous X-ray observations could only characterize the spectra of a few regions. Here, we examine the spectra from 14 regions surrounding the entire rim, finding that the spectral properties of the nonthermal emission do not vary significantly in any systematic way from one part of the forward shock to another, unlike several other remnants of this class. We confirm earlier findings that the power-law index, Γ, ranges from about 2.1–2.5, while the absorbing column density is generally between (2.0–2.6) × 1022 cm−2. Fits with the srcut model find values of the roll-off frequency in the range of 1017.1–1017.5 Hz, implying energies of accelerated electrons of ∼100 TeV. These values imply a high shock velocity of ∼4600 km s−1, favoring a young age of the remnant. Diffuse emission from the interior is nonthermal in origin as well, and fits to these regions yield similar values to those along the rim, also implying a young age. Thermal emission is present in the east, and the spectrum is consistent with a ∼650 km s−1 shock wave encountering interstellar or circumstellar material with a density of ∼1 cm−3.
Discussion Paper Series High and Low Activity Spell in Housing Markets

This paper demonstrates the way in which stock-flow matching with endogenous seller entry generates hot and cold spells in house sales. Potential sellers know the number of bidders remaining from the last house sale. If two or more bidders remain, the seller obtains the gains to trade through competitive bidding. The market is active. With one monopolistic bidder, the buyer captures the surplus and sellers become unwilling to enter. The market remains dormant until sellers think enough time has passed for buyer entry to have replenished the market and make entry profitable. The resulting pattern of trade matches up with observations from Wisconsin. JEL Codes : R31, D53
Critical elements of an expedition experience

Abstract Much of the research in outdoor education has focused on participant outcomes rather than the aspects of the experience that elicited those outcomes. This study explores the key elements of a 10-week expedition to Ghana with Raleigh International. Data collection involved five rounds of interviews with 14 British participants over a one-year period, using categorical aggregation to determine five principal themes critical to the experience. The findings highlight the importance of diverse groups living in isolated environments. Changing groups and moving to a new physical setting after four weeks and again at seven weeks was regarded as a challenging but necessary feature of the programme. Finally, there is little evidence linking specific programme activities with specific participant outcomes. It is more important that the experience should emphasise self-sufficient living conditions and physically demanding activities.
Improvement of fruit quality by moderate water deficit in three plum cultivars (Prunus salicina L.) cultivated in a semi-arid region

Introduction. Drought can affect the qualitative and nutritional attributes of plum (Prunus salicina L.) . The aim of this work was to study the effect of regulated deficit irrigation (RDI) on the quality of plum fruits. Materials and methods. Experiments were conducted during two consecutive seasons (2011-2012) with three cultivars (‘Black Diamond’, ‘Black Gold’ and ‘Black Star’) recently introduced in the region of Regueb (center of Tunisia) characterized by a semi-arid climate. During the fruit growth period, treated trees (RDI 50) received 50% of the irrigation water provided to the control (CI) for three months. Results and discussion.Water restriction reduced the diameter and weight of the fruit though the extent depended on the cultivar. However, other measures of fruit quality were improved for all cultivars with an increase of fruit firmness, pH, soluble solids and sucrose content, and a decrease of total acidity. Additionally, ‘Black Diamond’ fruit from treated trees had high level of total phenolics and flavonoids. Conclusion. Regulated deficit irrigation may save water in semi-arid regions and improve fruit quality with only moderate impact on productivity.
Salinity strongly drives the survival, growth, leaf demography, and nutrient partitioning in seedlings of Xylocarpus granatum J. König

Abstract: Salinity is increasing in the Sundarbans (Bangladesh) due to sea-level rise and the reduction of fresh water flow. Xylocarpus granatum is one of the most valuable mangrove tree species of the Sundarbans. We conducted a six-month long study to investigate the effect of salinity on the survival, growth, leaf demography, and nutrient partitioning in parts of X. granatum seedlings. Our results showed that most of the seedlings (90%) survived at 0 to 5 PSU salinity, and this survival percentage was found to decrease at higher saline conditions. Salinity of more than 25 PSU was lethal to the plants as no seedlings survived under these conditions. In this salinity (25 PSU), accelerated leaf fall coupled with a reduction in the new leaves caused loss of leaves. The relative growth rate (RGR) was higher at 0 to 5 PSU salinity, and conversely, a lower growth rate was observed with increased salinity. Higher saline conditions created stress, which inhibited nutrient (N, P and K) accumulation in different parts (leaf, stem, bark and root) of the seedlings. We concluded that salinity is a critical factor for the growth and survival of X. granatum either by inhibiting plant nutrient uptake or due to salinity related toxicity.
An Improved Wheeler Residual Stress Model For Remaining Life Assessment of Cracked Plate Panels

In this paper an improved Wheeler residual stress model has been proposed for remaining life assessment of cracked plate panels under variable amplitude loading (VAL). The improvement to the Wheeler residual stress model is in terms of the expressions for the shaping exponent, which is generally obtained through experiments. Simple expressions for the computation of shaping exponent have been proposed for compact tension (CT) specimen and plate panels with a center crack or an edge crack. The remaining life assessment has been carried out by employing linear elastic fracture mechanics (LEFM) principles. In the present study, the degree of influence of overload ratio (OLR) and the shape factor (β) on the shaping exponent have been investigated for remaining life assessment of cracked plate panels under tensile overload. It is observed that the parameters OLR and β have differing influences on the shaping exponent. Crack growth studies have been conducted on CT specimen and plate panels with a center crack or an edge crack subjected to tensile overloads for validating the proposed expressions. It is observed from the studies that the remaining life predicted using the improved Wheeler model for these plate panels are in close agreement with the experimental values reported in literature. keyword: Fracture mechanics, overload, crack growth, remaining life
The extent and intensity of the 1998 mass bleaching event on the reefs of Mauritius, Indian Ocean

The most severe and large scale-bleaching event on record occurred in 1998 world-wide. In Mauritius, three surveys covering 2 habitats at 4-5 sites were conducted to describe and quantify the event. Bleaching was recorded at all sites and habitats. However, relatively few corals were bleached (<10%) except at one localised site (Le Bouchon: 38.6%) indicating that Mauritius was one of the few islands in the Indian Ocean to have sustained a comparatively mild bleaching episode. On the reef flat Acropora species were generally more susceptible to bleaching than non-Acropora species. In contrast on the reef slopes, non-Acropora species were more affected than the Acropora species. Furthermore, susceptibility to bleaching differed within colonies and species. The main cause of this bleaching event was most likely due to an increase in seawater temperature and solar radiation, exacerbated by lowered salinity from higher seasonal rainfall.
OPTICAL PHOTOMETRIC AND POLARIMETRIC INVESTIGATION OF NGC 1931

We present optical photometric and polarimetric observations of stars toward NGC 1931 with the aim of deriving cluster parameters such as distance, reddening, age, and luminosity/mass function as well as understanding dust properties and star formation in the region. The distance to the cluster is found to be 2.3 ± 0.3 kpc and the reddening E(B − V) in the region is found to be variable. The stellar density contours reveal two clusters in the region. The observations suggest a differing reddening law within the cluster region. Polarization efficiency of the dust grains toward the direction of the cluster is found to be less than that for the general diffuse interstellar medium (ISM). The slope of the mass function (−0.98 ± 0.22) in the southern region in the mass range of 0.8 < M/M☉ < 9.8 is found to be shallower in comparison to that in the northern region (−1.26 ± 0.23), which is comparable to the Salpeter value (−1.35). The K-band luminosity function (KLF) of the region is found to be comparable to the average value of the slope (∼0.4) for young clusters obtained by Lada & Lada; however, the slope of the KLF is steeper in the northern region as compared to the southern region. The region is probably ionized by two B2 main-sequence-type stars. The mean age of the young stellar objects (YSOs) is found to be 2 ± 1 Myr, which suggests that the identified YSOs could be younger than the ionizing sources of the region. The morphology of the region, the distribution and ages of the YSOs, and ionizing sources indicate a triggered star formation in the region.
A model for the management of sexual harassment in South African companies

Sexual harassment is an issue shrouded in both controversy and ambiguity. As the literature indicates, its presence manifests itself negatively on both the well-being of the employees and the organisation. Consequently, management need to view sexual harassment as an area of concern because it ultimately affects the overall efficiency of organisations. The existing theoretical principles relating to the management of sexual harassment in the workplace have been analysed in depth, and a model is proposed which introduces, describes and integrates the various processes, steps and actions required for the efficient and effective management of sexual harassment in the workplace.
Genetic Data Concerning Shigella flexneri Serotypes 5 and 6

It is shown that the genetic determinants of type-specific antigens 1 to V of Shigella flexneri controlling similar functions are localized near the lactose-fermentation region on the chromosome; the determinant of antigen VI lies beyond it. The authors support the proposal that Shigella flexneri serotype 6 be excluded from Shigella flexneri and be considered as a subspecies in correspondence with the Soviet scheme of classification or even as a distinct species as Slopek and Mulczyk suggested. Genetic arguments based on the different behavior of S. flexneri strains in recombination with Escherichia coli K–12 Hfr are presented which support the division of S. flexneri serotype 5 into two subtypes, a and b, in correspondence with a similar division of other serotypes. The advisability of this division is confirmed by receptor analysis demonstrating differences in group-specific factors in strains of serotype 5. The antigenic formula of subtype 5b is V:7 … and of 5a, V:4 ….
Determinants of social media usage among a sample of rural South African youth

Background: Youths have been found to utilise and adopt information communication technology (ICT) faster than any other population cohort. This has been aided by the advent of social media, especially Facebook and Instagram as platforms of choice. Calls have been made for more research (especially in rural communities) on the usage of ICT platforms such as social media among the youth as a basis for interventions that not only allow for better communication but also for learning. Objectives: The research investigated the relationship between knowledge sharing, habit and obligation in relation to social media usage among a sample of rural South African youth. Method: This study is descriptive by design. Primary data were collected from 447 youths domiciled within a rural community in the Eastern Cape Province of South Africa using a self-administered questionnaire. The respondents to the study were all social media users. A combination of descriptive statistics and Pearson’s correlation analysis was used to make meaning of the data. Results: The study found a significant positive correlation to exist in all three independent variables (knowledge sharing, habit and obligation) with the dependent variable (social media usage) concerning Facebook usage among the sample of South African rural youth. Conclusion: Based on the findings of the research, recommendations and implications with regard to theory and practice are made.
Production of Natural Pigments From Novel local Psychrotolerant Kocuria spp.

Two local psychrotolerant coloured bacteria, Kocuria polaris MO and Kocuria carniphila MY, which were isolated from Nile river during winter in Kafer El-Shakhe-Egypt. They were investigated for natural pigments production as K. carniphila MY was a yellow isolate and K.polaris MO was an orange one. These natural pigments were extracted using acetone after cultivating both isolates on King's medium and being incubated at 10°C for 7 days. Low incubation temperatures for both bacterial isolates were found to enhance production of large amount of pigments which was seen to be reduced by increasing temperature till it was completely vanished above 30°C. On the other hand, a pH value of 7-8 was optimum for pigmentation in both strains. Light was found to be suppressive for pigmentation in both isolates where in dark places pigment production was improved rather than in lightened ones. No significant difference was shown on pigmentation after incubating cells once static, and then shaken. Bacterial pigments were then identified by TLC, where it was found that K. carniphila MY contains β-carotene and xanthophylls, while K.polaris MO contains β-carotene and echinenone. Pigments were then separated by column chromatography and it was found that K. carniphila MY contains 0.127 mg/g of β-carotene and 4.073 mg/g xanthophills while K. polaris MO contains 0.308 mg/g of β-carotene and 0.2 mg/g of echinenone. β-carotene, echinenone and xanthophylls were determined spectrophotometrically after separation. (Yusef, HH, Belal MA, El-Sharouny, EE. Production of Natural Pigments From Novel Local Psychrotolerant
Temptation in economic decision making: effects of immediate reward and reward-cues

Immediate exposure to reward or reward-predicting stimuli (cues) influences behavior. For example, chips placed right in front of us are likely to get eaten even if we wish to lose weight or don't actually like chips so much. In this paper we review evidence that shows that immediate exposure to reward and the presence of reward-cues can change economic behavior across various decision domains. Reward cues lead to less patient intertemporal choice, seem to increase risk aversion, and bias consumer choice. This may explain various, at first glance very different, behavioral phenomena, such as dynamic inconsistency, the certainty effect, and the endowment effect. We suggest that immediacy in time, certainty, and physical possession all create immediacy to a rewarding outcome that might bias choice in a similar way as other reward-predicting stimuli.
Seismic hazard assessment in terms of macroseismic intensity for the Italian area a cura di

A seismic hazard map, in terms of macro seismic intensity with 10% probability of exceedance in 50 years, is proposed for the Italian territory. The input elements used to evaluate the seismic hazard are: the seismogenic zoning ZS9 (Meletti et al., 2007), the earthquake catalogue CPTI04 (Gruppo di lavoro CPTI04, 2004) and intensity attenuation relationships. The first two elements and the historical and statistical completeness of the catalogue are those used in the national seismic hazard map for Italy MPS04 (Gruppo di Lavoro MPS, 2004). Two intensity attenuation models are used: 1) one national relationship obtained with a new approach by Pasolini et al. (2006) and a relationship for the Etna volcanic zone proposed by Azzaro et al. (2006) 2) a set of regional relationships derived from a previous cubic model (Berardi et al., 1993) which is recalibrated in the present study using the macro seismic intensity database DBMI04 (Stucchi et al., 2007), which was used for compiling CPTI04. The computer code adopted to evaluate the seismic hazard, with the elements cited above, is SeisRisk III (Bender and Perkins, 1987), which has been modified within this study to incorporate the aleatory variability of the ground motion (macroseismic intensity). A logic-tree framework allowed to explore some possible alternatives of epistemic character. The seismic hazard map obtained in terms of intensity was subsequently transformed into PGA by means of a linear relation between intensity and PGA, in order to compare it with the recently national seismic hazard map MPS04.
Distinct root-associated bacterial communities on three wild plant species growing in a common field

Plant roots are known to harbor large and diverse communities of bacteria. It has been suggested that plant identity can structure these root-associated communities, but few studies have specifically assessed how the composition of root microbiota varies within and between plant species growing under natural conditions. We sampled endophytic and epiphytic bacteria in root tissues from a population of a wild, clonal plant (Orange hawkweed – Pilosella aurantiaca) as well as two neighboring plant species (Oxeye daisy – Leucanthemum vulgare and Alsike clover – Trifolium hybridum) to determine if plant species hosted unique root microbiota. Our results show that plants of different species host distinct bacterial communities in their roots. In terms of community composition, Betaproteobacteria (especially the family Oxalobacteraceae) were found to dominate in the root microbiota of L. vulgare and T. hybridum samples, whereas the root microbiota of P. aurantiaca had a more heterogeneous distribution of bacterial abundances where gamma Proteobacteria and Acidobacteria occupied a larger portion of the community. Whether all plant species host their own distinct root microbiota and plants more closely related to each other share more similar bacterial communities still remains to be explored.
THE IMPACT OF MNES ON DOMESTIC FIRMS IN CEECS: A MICRO-ECONOMETRIC APPROACH

Many governments in Central and Eastern European Countries (CEECs) have offered significant incentives in order to attract foreign investments, motivated by expectations on possible spillover benefits. FDI is usually perceived as a vehicle for transferring technology not only across national boundaries but also between firms, i.e. between foreign and domestic firms. When a foreign firm enters a new market, it generates different reactions from domestic firms. Additional competition pushes for efficiency improvements, which become necessary if firms want to keep their market shares. Domestic firms may learn from foreign companies about new products, production techniques and organization skills, thus increasing their performance. This transfer of benefits may occur either voluntarily, through input output linkages between domestic and foreign firms, or involuntarily through competition, imitation and training. The final result, however, is the same: domestic firms become more productive and efficient, thus fostering local industrial development, as suggested by several economists, from Hirschman (1954) to Markusen and Venables (1999). Despite this long theoretical tradition, there is little conclusive evidence supporting this claim. This paper focuses on the role played by multinational enterprises in fostering the economic development of the hosting regions in Central and Eastern European Countries (CEECs) by testing whether and to what extent technology transfer between domestic and foreign firms does occur. We distinguish not only between horizontal and vertical effects, but also, within the latter, between contacts between domestic suppliers of intermediate inputs and their multinational customers, and contacts between foreign suppliers of intermediates inputs to their domestic clients. The analysis is based on an unbalance panel of about 30,000 domestic firms and about 7,000 foreign firms operating in the manufacturing sector in Bulgaria, Czech R. , Hungary, Poland and Romania. The years covered are 1993 through 2002. From a methodological point of view, we adopt the semiparametric estimation method suggested by Olley and Pakes (1996) to account for endogeneity of input demand, and test for the presence of several specific effects, such as country, region, time and sector effects.