Miracle-dz/UniFAR-FTUs huggingface dataset:
Numerical Modeling of Flow Conditions during Steel Filtration Experiments

In the present article, the performance and the efficiency of ceramic filters for continuous steel filtration in an induction crucible furnace, which is part of the steel casting simulator facility located at Technische Universität Bergakademie Freiberg, is investigated numerically. In order to achieve this objective, a macro‐scale simulation for the melt flow in the crucible is coupled with a pore‐scale simulation for the flow inside the ceramic filter that is adequately resolved by its detailed filter geometry, obtained from computed tomography scan images. The considerable influence of the filter on the flow field is indicated from the present results. Moreover, the efficiency of the employed filter is also determined and compared for two pore densities.
Second order statistics of rain attenuation time series generated with-state Markov chain model

Point-to-point and point-to-multipoint connections operating at high frequencies become increasing importance in the near future wireless communication systems. These systems are applied in feeder network for future cellular mobile communication system or BFWA (broadband fixed wireless access) networks. For accurate planning of the proposed microwave links the estimation of the CCDF (complement cumulative distribution function) of attenuation is highly important to achieve appropriate outage performance. In this work an N-state Markov chain model is investigated, which is used to generate attenuation time series influenced of those wireless links. With our proposed model very accurate realization of the physical fade process can be achieved. This work mainly focuses on the comparison of the generated and the measured attenuation time series, both the first and second order statistics of attenuation will be examined.
Compression Fatigue Behavior of Graphite/Epoxy in the Presence of Stress Raisers

Graphite/epoxy composites are being applied to aircraft structures because of their demonstrated capability to reduce weight and increase life. Although composites have better fatigue properties than metals, their behavior differs significantly. Unlike metals, composites exhibit excellent tensile fatigue behavior-the constant amplitude fatigue strength at 10 7 cycles being close to static ultimate. Compression and reversed loading fatigue behavior in the presence of stress raisers, however, has not been well characterized. This program was therefore undertaken to determine the characteristics of composites under these conditions. Two stress raisers were considered; the first was an open hole and the second was damage resulting from low velocity, hard object impact. For the open hole specimen, constant and variable amplitude tests were performed to determine the significance of compression fatigue and to investigate the failure mechanism. These tests indicated that the fatigue life under compression and reversed loading is less than for tension-tension loading and will be an important design consideration in future composite applications. The failure mechanism appeared to be local progressive failure of the matrix near the stress raiser resulting in delamination, and final failure by fiber buckling. The variable-amplitude loading results also demonstrated the unconservativeness of Miner's rule for making analytical predictions. In order to determine the nature and significance of impact damage to generic composite structural elements, low velocity impact and residual properties tests were conducted on solid laminate specimens of 42 and 48 plies thick and on honeycomb sandwich specimens with 12-ply composite face sheets. Results of post impact properties tests indicate subvisual damage can degrade compression static and fatigue strength, although subvisual damage will not propagate under moderate (0.003) cyclic strain.
Sound attenuation of polymerizing actin reflects supramolecular structures: viscoelastic properties of actin gels modified by cytochalasin D, profilin and alpha-actinin.

Polymerization and depolymerization of cytoskeletal elements maintaining cytoplasmic stiffness are key factors in the control of cell crawling. Rheometry is a significant tool in determining the mechanical properties of the single elements in vitro. Viscoelasticity of gels formed by these polymers strongly depends on both the length and the associations of the filaments (e.g. entanglements, annealings and side-by-side associations). Ultrasound attenuation is related to viscosity, sound velocity and supramolecular structures in the sample. In combination with a small glass fibre (2 mm x 50 microm), serving as a viscosity sensor, an acoustic microscope was used to measure the elasticity and acoustic attenuation of actin solutions. Changes in acoustic attenuation of polymerizing actin by far exceed the values expected from calculations based on changes in viscosity and sound velocity. During the lag-phase of actin polymerization, attenuation slightly decreases, depending on actin concentration. After the half-maximum viscosity is accomplished and elasticity turns into steady state, attenuation distinctly rises. Changes in ultrasound attenuation depend on actin concentration, and they are modulated by the addition of alpha-actinin, cytochalasin D and profilin. Thus absorption and scattering of sound on the polymerization of actin is related to the packing density of the actin net, entanglements and the length of the actin filaments. Shortening of actin filaments by cytochalasin D was also confirmed by electron micrographs and falling-ball viscosimetry. In addition to viscosity and elasticity, the attenuation of sound proved to be a valuable parameter in characterizing actin polymerization and the supramolecular associations of F-actin.
A Search-Based Approach for Bayesian Inference of the T-cell Signaling Network

We apply a search-based technique for learning high-quality Bayesian networks to proteomic flowcytometry data for a portion of the human T-cell signaling network. Although Bayesian network models have been learned from this data using methods such as MCMC that sample from a posterior distribution [1], [2], [3], we demonstrate that our more comprehensible searchbased technique, which uses model averaging by Bayesian bootstrap replicates, provides comparable results. We also show that additional edges not in the consensus model, but identified by both our technique and that of Eaton and Murphy are very unlikely to be artifacts of the network learning technique, and should be investigated further.
Trends in Primary Production in the Canary Current Upwelling System—A Regional Perspective Comparing Remote Sensing Models

After Andrew (Bakun, 1990) formulated his hypothesis of upwelling intensification caused by increasing global warming, contradictory results have been published on whether primary productivity is increasing or decreasing in Eastern Boundary Upwelling Ecosystems (EBUE). The present work is focused in comparing three net primary production (NPP) models -the VGPM (Vertically Generalized Production Model), the Eppley-VGPM and the CbPM (Carbon-based Production Model)- in the Canary Current (CanC) EBUE during the 1998-2015 period, making use of both SeaWiFS (Sea-viewing Wide Field-of-view Sensor) and MODIS (MODerate-resolution Imaging Spectroradiometer) derived data. We looked for the first time for seasonal to interannual trends of NPP under a regional perspective, with the aim of searching for temporal patterns that could support or reject the intensification hypothesis. According to previous studies based on the seasonality of the upwelling regime, the CanC EBUE was divided into three subregions: a seasonal upwelling zone (SUZ; 13-20oN), a permanent upwelling zone (PUZ; 20-26oN) and a weak permanent upwelling zone (WPUZ; 26-33oN). Our analyses do not show significant increasing trends in NPP with any of the productivity models used, challenging Bakun’s hypothesis. Nevertheless, differences in the output of the models are important, both at regional and subregional scales, questioning the accuracy of the models. The comparison made in this work clearly shows the disagreements between some of the best-known NPP models and calls for a validation effort in this region. Contrary to the open-ocean, temperature trends show significant decreases in certain areas over the shelf waters, which might indicate an increase of cool, upwelled waters in those regions. Seasonal to decadal anomalies of NPP and sea-surface temperature (SST) are estimated and analyzed in relation to selected climate indices, yielding only significant correlations between SST and the North Atlantic Oscillation (NAO) indices.
On the effectiveness of IP reputation for spam filtering

Modern SMTP servers apply a variety of mechanisms to stem the volume of spam delivered to users. These techniques can be broadly classified into two categories: pre-acceptance approaches, which apply prior to a message being accepted (e.g. IP reputation), and post-acceptance techniques which apply after a message has been accepted (e.g. content based signatures). We argue that the effectiveness of these measures varies based on the SMTP sender type. This paper focuses on the most light-weight pre-acceptance filtering mechanism — IP reputation. We first classify SMTP senders into three main categories: legitimate servers, end-hosts, and spam gangs, and empirically study the limits of effectiveness regarding IP reputation filtering for each category. Next, we develop new techniques that build custom IP reputation lists, which significantly improve the performance of existing IP reputation lists. In compiling these lists, we leverage a somewhat surprising fact that both legitimate domains and spam domains often use the DNS Sender Policy Framework (SPF) in an attempt to pass simple authentication checks. That is, good/bad IP addresses can be systematically compiled by collecting good/bad domains and looking up their SPF resource records. We also evaluate the effectiveness of these lists over time. Finally, we aim to understand the characteristics of the three categories of email senders in depth. Overall, we find that it is possible to construct IP reputation lists that can identify roughly 90% of all spam and legitimate mail, but some of the lists, i.e. the lists for spam gangs, must be updated on a constant basis to maintain this high level of accuracy.
A classification of strategies employed by high school students in isomorphic combinatorial problems

Combinatorics plays an important role in school mathematics. This theme has been recurrent in the mathematics education literature (Fischbein & Gazit, 1988; English, 2005; Lesh & Heger, 2001; Muter 1999; Sriraman & English, 2004), as well as numerous curricular documents worldwide (NCTM, 1991, 2000). Among the most influential is work of Kapur (1970) who called for incorporating enumerative combinatorics in the school curriculum. He elicited the following reasons to justify the teaching of elementary combinatorics in schools:
Lattice-based memory allocation

We investigate the problem of memory reuse in order to reduce the memory needed to store an array variable. We develop techniques that can lead to smaller memory requirements in the synthesis of dedicated processors or to more effective use by compiled code of software-controlled scratchpad memory. Memory reuse is well-understood for allocating registers to hold scalar variables. Its extension to arrays has been studied recently for multimedia applications, for loop parallelization, and for circuit synthesis from recurrence equations. In all such studies, the introduction of modulo operations to an otherwise affine mapping (of loop or array indices to memory locations) achieves the desired reuse. We develop here a new mathematical framework, based on critical lattices, that subsumes the previous approaches and provides new insight. We first consider the set of indices that conflict, those that cannot be mapped to the same memory cell. Next, we construct the set of differences of conflicting indices. We establish a correspondence between a valid modular mapping and a strictly-admissible integer lattice-one having no nonzero element in common with the set of conflicting index differences. The memory required by an optimal modular mapping is equal to the determinant of the corresponding lattice. The memory reuse problem is thus reduced to the (still interesting and nontrivial) problem of finding a strictly admissible integer lattice-of least determinant. We then propose and analyze several practical strategies for finding strictly admissible integer lattices, either optimal or optimal up to a multiplicative factor, and, hence, memory-saving modular mappings. We explain and analyze previous approaches in terms of our new framework.
Type III restriction enzymes communicate in 1D without looping between their target sites

To cleave DNA, Type III restriction enzymes must communicate the relative orientation of two asymmetric recognition sites over hundreds of base pairs. The basis of this long-distance communication, for which ATP hydrolysis by their helicase domains is required, is poorly understood. Several conflicting DNA-looping mechanisms have been proposed, driven either by active DNA translocation or passive 3D diffusion. Using single-molecule DNA stretching in combination with bulk-solution assays, we provide evidence that looping is both highly unlikely and unnecessary, and that communication is strictly confined to a 1D route. Integrating our results with previous data, a simple communication scheme is concluded based on 1D diffusion along DNA.
A fracture mechanics analysis for delamination growth during impact on composite plates

A fracture mechanics analysis has been developed that describes the progress of delamination damage in composite plates struck by a hard spherical object. The analysis is based on large deflection plate mechanics for circular isotropic plates wherein multiple axisymmetric delaminations grow. Test data show that the analysis predicts the influence of plate thickness, support conditions, and matrix toughness on the onset and propagation of delamination.
A complete sample of Seyfert galaxies selected at 0.25 keV

We have used the ROSAT Bright Source Catalogue to extract a complete sample of sources selected in the band from 0.1-0.4 keV. This 0.25 keV-selected sample is composed of 54 Seyfert galaxies, 25 BL Lacertae objects, 4 clusters and 27 Galactic stars or binaries. Seyfert-type galaxies with 'ultrasoft' X-ray spectra can very often be classed optically as narrow-line Seyfert 1s (NLS1s). Such objects are readily detected in 0.25 keV surveys; the sample reported here contains 20 NLS1s, corresponding to a 40 per cent fraction of the Seyferts. Optical spectra of the Seyfert galaxies were gathered for correlative analysis, which confirmed the well-known relations between X-ray slope and optical spectral properties (e.g. [QIII]/Hβ ratio; Fe II strength, Hβ width). The various intercorrelations are most likely driven, fundamentally, by the shape of the photoionizing continuum in Seyfert nuclei. We argue that a steep X-ray spectrum is a better indicator of an 'extreme' set of physical properties in Seyfert galaxies than is the narrowness of the optical Hβ line. The correlation studies were also used to isolate a number of Seyfert galaxies with apparently 'anomalous' properties. Of particular interest are the six objects with relatively weak permitted line emission (Hβ and Fe II) and weak optical continua. Such objects are rare in most surveys, but two of these (IC 3599 and NGC 5905) are known to be transient active galactic nuclei in which the X-ray flux has faded by factors ∼100. If the other four objects also turn out to be transient, this would demonstrate that 0.25 keV surveys provide an efficient way of finding an interesting class of object. Finally, the luminosity function of the 0.25 keV-selected Seyfert galaxies was determined and broken down into subsamples to investigate the relative space densities of Seyferts when separated on the basis of either X-ray slope or Hβ linewidth.
Integrating Knowledge in Groups: How Formal Interventions Enable Flexibility

Recent perspectives have focused on the role of the firm in the generation and use of knowledge. These perspectives suggest that, while knowledge is "owned" at the individual level, the integration of this knowledge to a collective level is necessary. This integration of knowledge typically takes place in groups. In our experimental study, we examine how individuals in groups engage in micro-level interactions to effectively integrate knowledge by examining the effects of using three formal interventions: Information Sharing, Questioning Others, and Managing Time. In particular, we observe that simple formal interventions can improve knowledge integration when they lead to "windows of opportunity" for group members to consider ways to improve their work process that go beyond the formal intervention instructions. The most effective groups used these formal interventions to focus their attention into organized clusters of activity, during which they significantly changed their work process and improved their subsequent knowledge integration. In particular, groups in the Questioning Others and Managing Time conditions exhibited greater knowledge integration than groups in the Information Sharing and Control conditions. Groups with high-knowledge integration paced their attention to both adaptive improvements to their process and task execution. Overall, this study identifies simple structures, interruptions, and time pacing as central to the emerging concept of group flexibility by which members enhance their performance on novel and/or ambiguous tasks. We note links to complexity theory and knowledge-based thinking as well.
Molecular characterisation of the Chlamydia pecorum plasmid from porcine, ovine, bovine, and koala strains indicates plasmid-strain co-evolution

Background. Highly stable, evolutionarily conserved, small, non-integrative plasmids are commonly found in members of the Chlamydiaceae and, in some species, these plasmids have been strongly linked to virulence. To date, evidence for such a plasmid in Chlamydia pecorum has been ambiguous. In a recent comparative genomic study of porcine, ovine, bovine, and koala C. pecorum isolates, we identified plasmids (pCpec) in a pig and three koala strains, respectively. Screening of further porcine, ovine, bovine, and koala C. pecorum isolates for pCpec showed that pCpec is common, but not ubiquitous in C. pecorum from all of the infected hosts. Methods. We used a combination of (i) bioinformatic mining of previously sequenced C. pecorum genome data sets and (ii) pCpec PCR-amplicon sequencing to characterise a further 17 novel pCpecs in C. pecorum isolates obtained from livestock, including pigs, sheep, and cattle, as well as those from koala. Results and Discussion. This analysis revealed that pCpec is conserved with all eight coding domain sequences (CDSs) present in isolates from each of the hosts studied. Sequence alignments revealed that the 21 pCpecs show 99% nucleotide sequence identity, with 83 single nucleotide polymorphisms (SNPs) shown to differentiate all of the plasmids analysed in this study. SNPs were found to be mostly synonymous and were distributed evenly across all eight pCpec CDSs as well as in the intergenic regions. Although conserved, analyses of the 21 pCpec sequences resolved plasmids into 12 distinct genotypes, with five shared between pCpecs from different isolates, and the remaining seven genotypes being unique to a single pCpec. Phylogenetic analysis revealed congruency and co-evolution of pCpecs with their cognate chromosome, further supporting polyphyletic origin of the koala C. pecorum. This study provides further understanding of the complex epidemiology of this pathogen in livestock and koala hosts and paves the way for studies to evaluate the function of this putative C. pecorum virulence factor.
Do On-Line Labor Market Intermediaries Matter? The Impact of AlmaLaurea on University-to-Work Transition

This paper evaluates the impact of the availability of electronic labor markets on the university-to-work transition. In particular, we analyze the effect of the intermediation activity carried on by the inter-university consortium, AlmaLaurea, on graduates' labor market outcomes. The different timing of universities' enrollment in AlmaLaurea allows us to apply the difference-in-differences method to a repeated cross section data set. If the usual assumption concerning parallel outcomes holds, AlmaLaurea reduces the individual unemployment probability and improves matching quality. Interestingly, we also find that on-line intermediaries foster graduates' geographic mobility.
Circuit Class Therapy or Seven-Day Week Therapy for Increasing Rehabilitation Intensity of Therapy after Stroke (CIRCIT): A Randomized Controlled Trial

Background Increased therapy has been linked to improvements in functional ability of people with stroke. Aim To determine the effectiveness of two alternative models of increased physiotherapy service delivery (seven-day week therapy or group circuit class therapy five days a week) to usual care. Method Three-armed randomized controlled trial with blinded assessment of outcome. People admitted with a diagnosis of stroke, previously independently ambulant and with a moderate level of disability were recruited. ‘Usual care’ was individual physiotherapy provided five-days a week. Seven-day week therapy was usual care physiotherapy provided seven-days a week. Participants in the circuit class therapy arm of the trial received physiotherapy in group circuit classes in two 90-min sessions, five-days a week. Primary outcome was distance walked on the six-minute walk test at four-weeks post-randomization. Results Two hundred eighty-three participants were randomized; primary outcome data were available for 259 (92%). In the seven-day arm participants received an additional three hours of physiotherapy and thosein the circuit class armanadditional 22 h. There were no significant between-group differences at four-weeks in walking distance (P = 0·72). Length of stay was shorter for seven-day (mean difference −2·9 days, 95% confidence interval −17·9 to 12·0) and circuit class participants (mean difference −9·2 days, 95% confidence interval −24·2 to 5·8) compared to usual care, but this was not significant. Conclusions Both seven-day therapy and group circuit class therapy increased physiotherapy time, but walking outcomes were equivalent to usual care.
New roles for FoxH1 in patterning the early embryo

FoxH1 (Fast1) was first characterized as the transcriptional partner for Smad proteins. Together with Smad2/4, it forms the activin response factor (ARF) that binds to the Mix.2 promoter in Xenopus embryos. Foxh1 is expressed maternally in Xenopus. Depletion of maternal Foxh1 mRNA results in abnormalities of head and dorsal axis formation. We show that FoxH1 is required, together with XTcf3/β catenin, to activate the zygotic expression of the nodal gene, Xnr3 in a Smad2-independent manner. In contrast, maternal FoxH1 acts as an inhibitor of Xnr5 and 6 transcription, preventing their upregulation on the ventral side of the embryo, by the maternal T-box transcription factor VegT. We conclude that maternal FoxH1 has essential, context-dependent roles in regulating the pattern of zygotic gene expression in the early embryo.