2,533 research outputs found
Large Deviations of the Smallest Eigenvalue of the Wishart-Laguerre Ensemble
We consider the large deviations of the smallest eigenvalue of the
Wishart-Laguerre Ensemble. Using the Coulomb gas picture we obtain rate
functions for the large fluctuations to the left and the right of the hard
edge. Our findings are compared with known exact results for finding
good agreement. We also consider the case of almost square matrices finding new
universal rate functions describing large fluctuations.Comment: 4 pages, 2 figure
A bibliometric study of the research area of videogames using Dimensions.ai database
Videogames are a very interesting area of research for fields as diverse as computer science, health, psychology or even social sciences. Every year a growing number of articles are published in different topics inside this field, so it is very convenient to study the different bibliometric data in order to consolidate the research efforts.
Thus, the aim of this work is to conduct a study on the distribution of articles related to videogames in the different fields of research, as well as to measure their interest over time, to identify the sources, countries and authors with the highest scientific production. In order to carry out this analysis, the information system Dimensions.ai has been considered, since it covers a large number of documents and allows for easy downloading and analysis of datasets.
According to the study, three countries are the most prolific in this area: USA, Canada and UK. The obtained results also indicate that the fields with the highest number of publications are Information and Computer Sciences, Medical and Health Sciences, and Psychology and Cognitive Sciences, in this order. With regard to the impact of the publications, differences between the number of citations, and the number of Altmetric Attention Score, have been found
A conceptual model of check dam hydraulics for gully control: efficiency, optimal spacing and relation with step-pools
There is little information in scientific literature regarding the
modifications induced by check dam systems in flow regimes within restored
gully reaches, despite it being a crucial issue for the design of gully
restoration measures. Here, we develop a conceptual model to classify flow
regimes in straight rectangular channels for initial and dam-filling
conditions as well as a method of estimating efficiency in order to provide
design guidelines. The model integrates several previous mathematical
approaches for assessing the main processes involved (hydraulic jump, impact
flow, gradually varied flows). Ten main classifications of flow regimes were
identified, producing similar results when compared with the IBER model. An
interval for optimal energy dissipation (ODI) was observed when the steepness
factor <i>c</i> was plotted against the design number (DN, ratio between the
height and the product of slope and critical depth). The ODI was
characterized by maximum energy dissipation and total influence conditions.
Our findings support the hypothesis of a maximum flow resistance principle
valid for a range of spacing rather than for a unique configuration. A value
of <i>c</i> = 1 and DN ~ 100 was found to economically meet the ODI
conditions throughout the different sedimentation stages of the structure.
When our model was applied using the same parameters to the range typical of
step-pool systems, the predicted results fell within a similar region to that
observed in field experiments. The conceptual model helps to explain the
spacing frequency distribution as well as the often-cited trend to lower <i>c</i>
for increasing slopes in step-pool systems. This reinforces the hypothesis of
a close link between stable configurations of step-pool units and man-made
interventions through check dams
A Study of a Road Landslide in Puerto Rico
Numerous landslides have plagued the construction of a 1.3 mile road sector in the mountainous region of central Puerto Rico. The area is underlain by a sequence of landslide deposits overlying a muddy limestone and hard overconsolidated clayey soils. Landslides have occurred in both cuts and fills that have delayed the road construction for a period of more than two years, bringing as a result, great economic losses for the Puerto Rico Highway Authority. The landslide trigger mechanism has been intimately related to high rainfall, commonly observed in this region. The geotechnical and geological studies performed previous to the construction of this road sector were few and meager. These studies did not recognize the presence of unstable deposits along the road sector alignment. As a result, several large slope failures developed during construction that halted the completion of the road. For investigating the slope failures, detailed geological and geotechnical studies were performed, including monitoring of groundwater levels, rainfall, and slope movements followed by laboratory and slope stability analyses. Remedial measures have been provided in the form of excavation, drainage, and stability berms. Renewal of the road construction with the remedial measures is prompt to start
La comunicación institucional y de servicios. Las páginas web municipales de las capitales de provincia españolas
El papel protagonista que ha adquirido la informática en estos últimos años obliga a los diferentes agentes e instituciones que conforman nuestra sociedad a adecuarse a los nuevos tiempos. Entre las administraciones públicas destaca el proceso de modernización y adaptación iniciado por las instituciones locales más próximas a los ciudadanos: los ayuntamientos. En este periodo de transformación, las nuevas tecnologías de la información y las comunicaciones ocupan un papel principal y nos conducen a una nueva Administración local donde desaparecen las limitaciones de tiempo y espacio. Se produce una revolución en la prestación de servicios y un cambio en las relaciones que mantienen los ciudadanos con los ayuntamientos. En esta investigación se va a estudiar si las webs municipales españolas son operativas y funcionales, para permitir la gestión de trámites burocráticos a través de la red y, por tanto, sin la necesidad de personarse en el consistorio.Computing has taken the chief role in the society during recent years and has compelled the diferent institutions that shape our society to adapt to the new situation. In the area of public Administration is notable the modernization and adaptation process started by the local institutions which are closer to the citizens: the city councils. In this period full of changes, the new information and communication technologies take the main role and lead us to a new local Administration where limits of time and space disappear. There is a change in the way services are offered and in the relationship between citizens and their city councils. In this investigation the authors have studied if the municipal webs are operative and functional allowing people to transact and to manage official documents without presenting oneself at city council
Von Neumann's expanding model on random graphs
Within the framework of Von Neumann's expanding model, we study the maximum
growth rate r achievable by an autocatalytic reaction network in which
reactions involve a finite (fixed or fluctuating) number D of reagents. r is
calculated numerically using a variant of the Minover algorithm, and
analytically via the cavity method for disordered systems. As the ratio between
the number of reactions and that of reagents increases the system passes from a
contracting (r1). These results extend the
scenario derived in the fully connected model (D\to\infinity), with the
important difference that, generically, larger growth rates are achievable in
the expanding phase for finite D and in more diluted networks. Moreover, the
range of attainable values of r shrinks as the connectivity increases.Comment: 20 page
Unify Markov model for Rational Design and Synthesis of More Safe Drugs. Predicting Multiple Drugs Side Effects
The 9th International Electronic Conference on Synthetic Organic Chemistry session Computational ChemistryMost of present mathematical models for rational design and synthesis of new drugs consider just the molecular structure. In the present article we pretend extending the use of Markov Chain models to define novel molecular descriptors, which consider in addition other parameters like target site or biological effect. Specifically, this model takes into consideration not only the molecular structure but the specific biological system the drug affects too. Herein, it is developed a general Markov model that describes 19 different drugs side effects grouped in 8 affected biological systems for 178 drugs, being 270 cases finally. The data was processed by Linear Discriminant Analysis (LDA) classifying drugs according to their specific side effects, forward stepwise was fixed as strategy for variables selection. The average percentage of good classification and number of compounds used in the training/predicting sets were 100/95.8% for endocrine manifestations(18 out of 18)/(13 out of 14); 90.5/92.3% for gastrointestinal manifestations (38 out of 42)/(30 out of 32); 88.5/86.5% for systemic phenomena (23 out of 26)/(17 out of 20); 81.8/77.3% for neurological manifestations (27 out of 33)/(19 out of 25); 81.6/86.2% for dermal manifestations (31 out of 38)/(25 out of 29); 78.4/85.1% for cardiovascular manifestation (29 out of 37)/(24 out of 28); 77.1/75.7% for breathing manifestations (27 out of 35)/(20 out of 26) and 75.6/75% for psychiatric manifestations (31 out of 41)/(23 out of 31). Additionally a Back-Projection Analysis (BPA) was carried out for two ulcerogenic drugs to prove in structural terms the physic interpretation of the models obtained. This article develops a model that encompasses a large number of drugs side effects grouped in specifics biological systems using stochastic absolute probabilities of interaction (Apk (j)) by the first time
CCAAT/Enhancer binding protein β induces motility and invasion of glioblastoma cells through transcriptional regulation of the calcium binding protein S100A4
This work is licensed under a Creative Commons Attribution 3.0 License.We have previously shown that decreased expression of CCAAT/Enhancer binding protein β (C/EBPβ) inhibits the growth of glioblastoma cells and diminishes their transformation capacity and migration. In agreement with this, we showed that C/ EBPβ depletion decreases the mRNA levels of different genes involved in metastasis and invasion. Among these, we found S100 calcium binding protein A4 (S100A4) to be almost undetectable in glioblastoma cells deficient in C/EBPβ. Here, we have evaluated the possible role of S100A4 in the observed effects of C/EBPβ in glioblastoma cells and the mechanism through which S100A4 levels are controlled by C/EBPβ. Our results show that C/EBPβ suppression significantly reduced the levels of S100A4 in murine GL261 and human T98G glioblastoma cells. By employing an S100A4-promoter reporter, we observed a significant induction in the transcriptional activation of the S100A4 gene by C/EBPβ. Furthermore, overexpression of S100A4 in C/EBPβ- depleted glioblastoma cells reverses the enhanced migration and motility induced by this transcription factor. Our data also point to a role of S100A4 in glioblastoma cell invasion and suggest that the C/EBPβ gene controls the invasive potential of GL261 and T98G cells through direct regulation of S100A4. Finally, this study indicates a role of C/EBPβ on the maintenance of the stem cell population present in GL261 glioblastoma cells.This work was supported by MINECO (SAF2010–16365) and by Fundación Mutua Madrileña (to A.P.-C.). CIBERNED is funded by the Instituto de Salud Carlos III. D.A.-M. is a fellow of the MINECO.Peer Reviewe
Characterization of varroa destructor mites in Cuba using mitochondrial and nuclear markers
Varroa destructor has been present in Cuba since 1996, but without the use of acaricidal infestation rates remain at very low levels. The presence of Korean haplotype mites was described in 2007, but there is no information regarding the introgression of the less virulent Japanese haplotype that could account for a low pathogenicity of the mite. In this research, we carried out molecular characterization of Cuban Varroa mites through mitochondrial DNA and hypervariable nuclear loci. We applied an alternative RFLP tech-nique and found that all the analyzed samples corresponded to Korean haplotypes. We analyzed the three STRs loci VD112, VD114 and VD016, previously described as highly variable and found new alleles in all of them, with an absolute allele size very different to those reported worldwide. We also detected genic and genotypic differentiation be-tween samples from two nearby locations (P=0.08). We also tested a new RFLP method for mite haplotype discrimination with an intra-reaction positive control of digestion
- …