Miracle-dz/UniFAR-FTUs huggingface dataset:
On the mean and variance of the writhe of random polygons

We here address two problems concerning the writhe of random polygons. First, we study the behavior of the mean writhe as a function length. Second, we study the variance of the writhe. Suppose that we are dealing with a set of random polygons with the same length and knot type, which could be the model of some circular DNA with the same topological property. In general, a simple way of detecting chirality of this knot type is to compute the mean writhe of the polygons; if the mean writhe is non-zero then the knot is chiral. How accurate is this method? For example, if for a specific knot type K the mean writhe decreased to zero as the length of the polygons increased, then this method would be limited in the case of long polygons. Furthermore, we conjecture that the sign of the mean writhe is a topological invariant of chiral knots. This sign appears to be the same as that of an ‘ideal’ conformation of the knot. We provide numerical evidence to support these claims, and we propose a new nomenclature of knots based on the sign of their expected writhes. This nomenclature can be of particular interest to applied scientists. The second part of our study focuses on the variance of the writhe, a problem that has not received much attention in the past. In this case, we focused on the equilateral random polygons. We give numerical as well as analytical evidence to show that the variance of the writhe of equilateral random polygons (of length n) behaves as a linear function of the length of the equilateral random polygon.
A Population Genetic Model for the Maintenance of R2 Retrotransposons in rRNA Gene Loci

R2 retrotransposable elements exclusively insert into the tandemly repeated rRNA genes, the rDNA loci, of their animal hosts. R2 elements form stable long-term associations with their host, in which all individuals in a population contain many potentially active copies, but only a fraction of these individuals show active R2 retrotransposition. Previous studies have found that R2 RNA transcripts are processed from a 28S co-transcript and that the likelihood of R2-inserted units being transcribed is dependent upon their distribution within the rDNA locus. Here we analyze the rDNA locus and R2 elements from nearly 100 R2-active and R2-inactive individuals from natural populations of Drosophila simulans. Along with previous findings concerning the structure and expression of the rDNA loci, these data were incorporated into computer simulations to model the crossover events that give rise to the concerted evolution of the rRNA genes. The simulations that best reproduce the population data assume that only about 40 rDNA units out of the over 200 total units are actively transcribed and that these transcribed units are clustered in a single region of the locus. In the model, the host establishes this transcription domain at each generation in the region with the fewest R2 insertions. Only if the host cannot avoid R2 insertions within this 40-unit domain are R2 elements active in that generation. The simulations also require that most crossover events in the locus occur in the transcription domain in order to explain the empirical observation that R2 elements are seldom duplicated by crossover events. Thus the key to the long-term stability of R2 elements is the stochastic nature of the crossover events within the rDNA locus, and the inevitable expansions and contractions that introduce and remove R2-inserted units from the transcriptionally active domain.
Students’ willingness to practice collaborative learning

ABSTRACT The study presented here sought to determine how student teachers’ personal characteristics, attitudes, knowledge, experience and skills for using collaborative learning influence their willingness to use this demanding pedagogy in their classes. A structural equation modeling (SEM) analysis model based on data from questionnaires emphasized the direct effect of experience on attitudes and skills, but showed no such effect on knowledge. There was no difference in research variables based on gender, age and degree in respondents’ willingness to integrate collaborative learning. One major conclusion of the study is that teacher education programs should include a study of the theoretical and strategic aspects of collaborative learning, as well as active experience with this pedagogy.
Obstructive urolithiasis in ruminants - a review.

Obstructive urolithiasis is the retention of urine subsequent to lodgment of calculi anywhere in the urinary conduct from up to urethral orifice. The disease results in heavy economic losses to the livestock industry as it is attributed the fifth most prevalent cause of death in feedlot. Obstructive urolithiasis is a serious, potentially fatal condition, most commonly causing symptoms in castrated male animals, but also occurring in breeding males. Many surgical approaches and techniques for the diagnosis and the treatment of the disease have been described with their relative merits and demerits in the literature.
Changes in The Normal Appearing White-Gray Matter and Cognitive Impairment in Clinically Isolated Syndrome

Changes in The Normal Appearing White-Gray Matter and Cognitive Impairment in Clinically Isolated Syndrome Müge KOÇAK, Kadriye AĞAN, Aynur MOLLAHASANOGLU, Gazanfer EKINCI, Neşe Tuncer-ELMACI, Dilek GÜNAL Marmara University School of Medicine, Neurology, Istanbul, Turkey Marmara University School of Medicine, Radiology, Istanbul, Turkey The first 2 authors (M.K. and K.A.) contributed equally to this study. The first 2 authors (M.K. and K.A.) contributed equally to this study; therefore, they share first authorship
Now and Forever? Initial and Subsequent Location Choices of Immigrants

This paper exploits a natural experiment to study the influence of regional factors on initial and subsequent location choices among immigrants. The results suggest that immigrants to Sweden are attracted to regions with high representation from the individual’s birth country and large overall immigrant populations. Labor market opportunities affect location decisions, but people also tend to choose localities with many welfare recipients. The impact of most regional factors does not change over time. Thus, there is little evidence that information improves or that preferences differ between initial and subsequent stages.
The psychological foundations of culture.

One of the strengths of scientific inquiry is that it can progress with any mixture of empiricism, intuition, and formal theory that suits the convenience of the investigator. Many sciences develop for a time as exercises in description and empirical generalization. Only later do they acquire reasoned connections within themselves and with other branches of knowledge. Many things were scientifically known of human anatomy and the motions of the planets before they were scientifically explained.
Suppression of CB1 Cannabinoid Receptor by Lentivirus Mediated Small Interfering RNA Ameliorates Hepatic Fibrosis in Rats

It is recognized that endogenous cannabinoids, which signal through CB1 receptors in hepatic stellate cells (HSCs), exert a profibrotic effect on chronic liver diseases. In this study, we suppressed CB1 expression by lentivirus mediated small interfering RNA (CB1-RNAi-LV) and investigated its effect on hepatic fibrosis in vitro and in vivo. Our results demonstrated that CB1-RNAi-LV significantly inhibited CB1 expression, and suppressed proliferation and extracellular matrix production in HSCs. Furthermore, CB1-RNAi-LV ameliorated dimethylnitrosamine induced hepatic fibrosis markedly, which was associated with the decreased expression of mesenchymal cell markers smooth muscle α-actin, vimentin and snail, and the increased expression of epithelial cell marker E-cadherin. The mechanism lies on the blockage of Smad signaling transduction induced by transforming growth factor β1 and its receptor TGF-β RII. Our study firstly provides the evidence that CB1-RNAi-LV might ameliorate hepatic fibrosis through the reversal of epithelial-to-mesenchymal transition (EMT), while the CB1 antagonists AM251 had no effect on epithelial-mesenchymal transitions of HSCs. This suggests that CB1 is implicated in hepatic fibrosis and selective suppression of CB1 by small interfering RNA may present a powerful tool for hepatic fibrosis treatment.
The Role of Developmental Networks in Building a Managerial Career

The purpose of this study is to examine the role of developmental networks in a managerial career. We argue that the 21st-century managerial career is constructed in interaction with developmental networks. The people around one and the prevailing situation can either promote or restrict a person’s career. We search for answers to the questions of (1) what kinds of developmental networks exist and (2) how developmental networks affect managerial careers. We interviewed 16 managers, both male and female, in semistructured thematic interviews. We discovered six core narratives of developmental networks: enticers, recognizers, supporters, challengers, blockers, and demotivators. Our results highlight the importance of support and developmental networks in managerial careers.
Interleukin 10 inhibits growth and granulocyte/macrophage colony- stimulating factor production in chronic myelomonocytic leukemia cells

Autonomous release of hematopoietic growth factors may play a crucial role in the pathogenesis of certain hematological malignancies. Because of its cytokine synthesis-inhibiting action, interleukin 10 (IL-10) could be a potentially useful molecule to affect leukemic cell growth in such disorders. Chronic myelomonocytic leukemia (CMML) cells spontaneously form myeloid colonies (colony-forming units- granulocyte/macrophage) in methylcellulose, suggesting an autocrine growth factor-mediated mechanism. We studied the effect of recombinant human IL-10 (rhIL-10) on the in vitro growth of mononuclear cells obtained from peripheral blood or bone marrow of patients with CMML. IL- 10 specifically binding to leukemic cells had a profound and dose- dependent inhibitory effect on autonomous in vitro growth of CMML cells. IL-10 significantly inhibited the spontaneous growth of myeloid colonies in methylcellulose in 10/11 patients, and autonomous CMML cell growth in suspension in 5/5 patients tested. Spontaneous colony growth from CMML cells was also markedly reduced by addition of antigranulocyte/macrophage colony-stimulating factor (GM-CSF) antibodies, but not by addition of antibodies against G-CSF, IL-3, or IL-6, IL-10-induced suppression of CMML cell growth was reversed by the addition of exogenous GM-CSF and correlated with a substantial decrease in GM-CSF production by leukemic cells, both at the mRNA and protein levels. Our data indicate that IL-10 profoundly inhibits the autonomous growth of CMML cells in vitro most likely through suppression of endogenous GM-CSF release. This observation suggests therapeutic evaluation of rhIL-10 in patients with CMML.
Geography, Deer, and Host Biodiversity Shape the Pattern of Lyme Disease Emergence in the Thousand Islands Archipelago of Ontario, Canada

In the Thousand Islands region of eastern Ontario, Canada, Lyme disease is emerging as a serious health risk. The factors that influence Lyme disease risk, as measured by the number of blacklegged tick (Ixodes scapularis) vectors infected with Borrelia burgdorferi, are complex and vary across eastern North America. Despite study sites in the Thousand Islands being in close geographic proximity, host communities differed and both the abundance of ticks and the prevalence of B. burgdorferi infection in them varied among sites. Using this archipelago in a natural experiment, we examined the relative importance of various biotic and abiotic factors, including air temperature, vegetation, and host communities on Lyme disease risk in this zone of recent invasion. Deer abundance and temperature at ground level were positively associated with tick abundance, whereas the number of ticks in the environment, the prevalence of B. burgdorferi infection, and the number of infected nymphs all decreased with increasing distance from the United States, the presumed source of this new endemic population of ticks. Higher species richness was associated with a lower number of infected nymphs. However, the relative abundance of Peromyscus leucopus was an important factor in modulating the effects of species richness such that high biodiversity did not always reduce the number of nymphs or the prevalence of B. burgdorferi infection. Our study is one of the first to consider the interaction between the relative abundance of small mammal hosts and species richness in the analysis of the effects of biodiversity on disease risk, providing validation for theoretical models showing both dilution and amplification effects. Insights into the B. burgdorferi transmission cycle in this zone of recent invasion will also help in devising management strategies as this important vector-borne disease expands its range in North America.
Eurographics/ Acm Siggraph Symposium on Computer Animation (2007) Arbitrary Cutting of Deformable Tetrahedralized Objects

Permission to make digital or hard copies of part or all of this wor k for per sonal or classr oom use is granted without fee provided that copies are not made or distributed for commer cial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this wor k owned by other s than ACM must be honored. Abstracting with cr edit is permitted. To copy other wise, to republish, to post on ser ver s, or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from Permissions Dept, ACM Abstract We propose a flexible geometric algorithm for placing arbitrary cracks and incisions on tetrahedralized de-formable objects. Although techniques based on remeshing can also accommodate arbitrary fracture patterns, this flexibility comes at the risk of creating sliver elements leading to models that are inappropriate for subsequent simulation. Furthermore, interactive applications such as virtual surgery simulation require both a relatively low resolution mesh for efficient simulation of elastic deformation and highly detailed surface geometry to facilitate accurate manipulation and cut placement. Thus, we embed a high resolution material boundary mesh into a coarser tetrahedral mesh using our cutting algorithm as a meshing tool, obtaining meshes that can be efficiently simulated while preserving surface detail. Our algorithm is similar to the virtual node algorithm in that we avoid sliver elements and their associated stringent timestep restrictions, but it is significantly more general allowing for the arbitrary cutting of existing cuts, sub-tetrahedron resolution (e.g. we cut a single tetrahedron into over a thousand pieces), progressive introduction of cuts while the object is deforming, and moreover the ability to accurately cut the high resolution embedded mesh.
Design for Social Presence in Online Communities: a Multi-Dimensional Approach

In online communities, numerous technical and social design decisions determine the social interaction space and affect the community participation. Social presence has been considered as a major design principle in computer-mediated communication. While most prior IS research adopts a uni-dimensional approach and restricts social presence to be the subjective nature of media, this research adopts a multi-dimensional approach (Shen and Khalifa 2007) to examine the online community design. Compared to uni-dimensional conceptualizations of presence/social presence, multi-dimensional conceptualizations can better capture the sense of social presence induced by both technical and social factors, and therefore entail more valuable implications for community design. The multi-dimensional approach also extends the developers’ impacts on online community, from interface design to user experience design. Built upon the work by Shen and Khalifa (2007) and Ma and Agarwal (2007), this study examines the technological antecedents of social presence dimensions. An online survey was conducted with four online forums. The empirical results provide interesting insights regarding the relative importance of three social presence dimensions in driving online community participation as well as the various correspondences between community artifacts and three social presence dimension.
Downregulation of B-cell lymphoma/leukemia-2 by overexpressed microRNA 34a enhanced titanium dioxide nanoparticle-induced autophagy in BEAS-2B cells

Titanium dioxide (TiO2) nanoparticles (TNPs) are manufactured worldwide for a wide range of applications and the toxic effect of TNPs on biological systems is gaining attention. Autophagy is recognized as an emerging toxicity mechanism triggered by nanomaterials. MicroRNA 34a (miR34a) acts as a tumor suppressor gene by targeting many oncogenes, but how it affects autophagy induced by TNPs is not completely understood. Here, we observed the activation of TNP-induced autophagy through monodansylcadaverine staining and LC3-I/LC3-II conversion. Meanwhile, the transmission electron microscope ultrastructural analysis showed typical morphological characteristics in autophagy process. We detected the expression of miR34a and B-cell lymphoma/leukemia-2 (Bcl-2). In addition, the underlying mechanism of TNP-induced autophagy was performed using overexpression of miR34a by lentivirus vector transfection. Results showed that TNPs induced autophagy generation evidently. Typical morphological changes in the process of autophagy were observed by the transmission electron microscope ultrastructural analysis and LC3-I/LC3-II conversion increased significantly in TNP-treated cells. Meanwhile, TNPs induced the downregulation of miR34a and increased the expression of Bcl-2. Furthermore, overexpressed miR34a decreased the expression of Bcl-2 both in messenger RNA and protein level, following which the level of autophagy and cell death rate increased after the transfected cells were incubated with TNPs for 24 hours. These findings provide the first evidence that overexpressed miR34a enhanced TNP-induced autophagy and cell death through targeted downregulation of Bcl-2 in BEAS-2B cells.
Endocrinological analysis of endothelium-dependent vasodilation in middle-aged patients with impaired glucose tolerance during prediabetes mellitus

Impaired glucose tolerance (IGT) is a pre-diabetic metabolic state involving heterogeneous and dynamic changes between the normal and diabetic state. The present study aimed to investigate the endocrine regulation of endothelium-dependent dysfunction in middle-aged patients with IGT and in patients with a normal glucose tolerance (NGT). An oral glucose tolerance test was performed to determine the NGT and IGT states. Physiological and biochemical analyses were performed. The carotid artery structure and function were investigated with Doppler supersonic diagnostic equipment. The functioning of the vascular endothelium was analyzed with physiological and biochemical indices in the IGT group. The results showed a significant reduction in endothelium-dependent vasodilation, but not in endothelium-independent vasodilation in the IGT group compared with those of the NGT group. It was identified that the intima-media thickness of the carotid artery and expression levels of endothelin-1 were significantly higher, whereas the endothelium-derived factor C-type natriuretic peptide levels were significantly lower in the IGT group compared with those in the NGT group. Notably, significant correlations were identified between endocrinological changes and body composition, including fat and glucose metabolism, in the IGT group. Our data indicate that vascular endothelial functions may be impaired by fat and glucose metabolism and body composition in IGT patients during prediabetes mellitusare.
Impact of Operations , Marketing , and Information Technology Capabilities on Supply Chain Integration

SCM requires collaboration of functions such as ope rations, marketing and information technology for internal and externa l integration. This study conceptualized supply chain integration as a higher level process integration capability comprised of operational, marketing and information technology capabilities. Operational capabilities include part ne selection, collaboration, learning and “operations human resources”. While pa rtner selection and collaboration are positively impacting integration, learning is not significant and “operations human resources” can be conceived to be negatively correlated with supply chain integration. IT infrastructure is sign ificantly impacting integration as well as performance directly. Market orientation is also significantly impacting integration. Market orientation has both direct eff ects on financial performance and indirect effects through supply chain integration. Supply chain integration is significantly impacting operational and customer-ba sed firm performance. JEL Classification Codes: M10, M31
Incidence and management of arterial anomalies in patients undergoing pancreaticoduodenectomy.

CONTEXT Pancreaticoduodenectomy entails ligation of vascular arcades arising from the celiac and superior mesenteric arteries. These are known to have anatomical variations. OBJECTIVE This study was aimed at analyzing the spectrum of arterial anomalies and their clinical impact on the procedure itself. PATIENTS The study includes 200 consecutive patients who underwent a pancreaticoduodenectomy between September 2003 and May 2009 after excluding those having distant metastases or local unresectability. MAIN OUTCOME MEASURES The records of the patients were studied to assess the incidence of arterial anomalies and the operative complexities involved in a pancreaticoduodenectomy. RESULTS Fifty-three patients (26.5%) had arterial anomalies. The complexity of the surgery was determined by the course of these arteries. The mean duration of surgery was 420 + or - 32.0 minutes in patients with arterial anomalies versus 370 + or - 38.5 minutes in those with a normal arterial anatomy (P=0.005). Fifty-one out of 53 (96.2%) patients underwent pancreaticoduodenectomy with negative resection margins. The pancreaticoduodenectomy was abandoned in two cases due to patient- and tumor-related factors. CONCLUSION During pancreaticoduodenectomy, arterial anomalies can increase operative complexity but do not usually compromise the safety of the procedure or its oncological outcome.