Significance analysis and statistical mechanics: an application to clustering

This paper addresses the statistical significance of structures in random data: Given a set of vectors and a measure of mutual similarity, how likely does a subset of these vectors form a cluster with enhanced similarity among its elements? The computation of this cluster p-value for randomly distributed vectors is mapped onto a well-defined problem of statistical mechanics. We solve this problem analytically, establishing a connection between the physics of quenched disorder and multiple testing statistics in clustering and related problems. In an application to gene expression data, we find a remarkable link between the statistical significance of a cluster and the functional relationships between its genes.Comment: to appear in Phys. Rev. Let

La necròpoli talaiòtica de S'Illot des Porros

El jaciment és situat dins del terme municipal de Santa Margalida, a la part meridional de la badia d' AIcúdia, damunt d'un petit illot de forma vagament el·lipsoidal, d'uns 70 m per 45 m, situat a uns 50 m de la línia de costa i a uns 500 m a l' oest de la gran necropoli de Son Real (o Punta deIs Fenicis) (Tarradell, 1964), amb la que guarda una relació evident (Uim. 1). La hipotesi que en epoca antiga hagués pogut estar unida aterra ferma (Tarradell, 1964,23) és, segons sembla, versemblant, pero de moment no ha estat verificada. Les restes arqueologiques es concentren a la meitat meridional, ja que la resta de l'illot a penes s'aixeca per damunt del nivell del mar i és batuda per les onades; no sembla probable que mai hi hagi hagut en aquesta zona cap tipus d'ocupació humana

El santuari talaiòtic de sa Punta des Patró (Santa Margalida, Mallorca)

El santuari de sa Punta des Patró és situat a la partida de Son Real, en el terme de Santa Margalida, al nord de l'illa de Mallorca, a uns 25 metres del mar, davant per davant de la necròpolis de s'Illa des Porros (Hernàndez, Sanmartí, 1998) i a uns 500 m de la famosa necròpolis de Son Real, també coneguda com a «Cementiri dels Fenicis» (Tarradell, Hernàndez, 1998). Les coordenades UTM són 516. 300 - 4. 400. 560. El jaciment fou descobert l'any 1996 arran d'una espoliació feta per excavadors furtius. Fins al moment s'hi ha fet dues campanyes (1998-1999), que han estat finançades per la Conselleria de Cultura del Consell Insular de Mallorca i per l'Ajuntament de Santa Margalida, institucions a les quals volem expressar el nostre reconeixement

The design and evaluation of a training program on culturally competent psychosocial care provision for men who have sex with men in Senegal

Men who have sex with men (MSM) experience a high degree of discrimination and marginalization in Senegal. Homophobia is pervasive in Senegalese society at the cultural, religious, and political levels. Its effects are reflected in the disproportionately high levels of depression, anxiety, and substance abuse among men who have sex with men when compared to the general population. Given the widespread stigma and the lack of structural support, healthcare providers play a critical role in reconciling the physical and psychological needs of men who have sex with men. This led to the design of a training program that aimed to improve the capacity of healthcare providers to deliver MSM-competent psychosocial care. The training was delivered virtually to 37 Senegal-based nurses and physicians. The program was quantitatively and qualitatively evaluated using pre- and post-testing. The findings demonstrate a general post-training increase in knowledge acquisition (9. 23%, p-value = 0.0021) and a 6.39% reduction in homophobia, which was statistically significant (p = 0.0376); with male providers outperforming female providers, and physicians outperforming nurses. This demonstrates the effectiveness and applicability of the program to support the psychosocial needs of men who have sex with men, and its capacity for future and broader implementation among healthcare providers

Ultrahigh-Temperature Ceramics

Ultrahigh temperature ceramics (UHTCs) are a class of materials that include the diborides of metals such as hafnium and zirconium. The materials are of interest to NASA for their potential utility as sharp leading edges for hypersonic vehicles. Such an application requires that the materials be capable of operating at temperatures, often in excess of 2,000 C. UHTCs are highly refractory and have high thermal conductivity, an advantage for this application. UHTCs are potentially applicable for other high-temperature processing applications, such as crucibles for molten-metal processing and high-temperature electrodes. UHTCs were first studied in the 1960 s by the U.S. Air Force. NASA s Ames Research Center concentrated on developing materials in the HfB2/SiC family for a leading-edge application. The work focused on developing a process to make uniform monolithic (2-phase) materials, and on the testing and design of these materials. Figure 1 shows arc-jet models made from UHTC materials fabricated at Ames. Figure 2 shows a cone being tested in the arc-jet. Other variations of these materials being investigated elsewhere include zirconium based materials and fiber-reinforced composites. Current UHTC work at Ames covers four broad topics: monoliths, coatings, composites, and processing. The goals include improving the fracture toughness, thermal conductivity and oxidation resistance of monolithic UHTCs and developing oxidation-resistant UHTC coatings for thermal-protection-system substrates through novel coating methods. As part of this effort, researchers are exploring compositions and processing changes that have yielded improvements in properties. Computational materials science and nanotechnology are being explored as approaches to reduce materials development time and improve and tailor properties

Visual data mining with self-organizing maps for ''self-monitoring'' data analysis

Data collected in psychological studies are mainly characterized by containing a large number of variables (multidimensional data sets). Analyzing multidimensional data can be a difficult task, especially if only classical approaches are used (hypothesis tests, analyses of variance, linear models, etc.). Regarding multidimensional models, visual techniques play an important role because they can show the relationships among variables in a data set. Parallel coordinates and Chernoff faces are good examples of this. This article presents self-organizing maps (SOM), a multivariate visual data mining technique used to provide global visualizations of all the data. This technique is presented as a tutorial with the aim of showing its capabilities, how it works, and how to interpret its results. Specifically, SOM analysis has been applied to analyze the data collected in a study on the efficacy of a cognitive and behavioral treatment (CBT) for childhood obesity. The objective of the CBT was to modify the eating habits and level of physical activity in a sample of children with overweight and obesity. Children were randomized into two treatment conditions: CBT traditional procedure (face-to-face sessions) and CBT supported by a web platform. In order to analyze their progress in the acquisition of healthier habits, self-register techniques were used to record dietary behavior and physical activity. In the traditional CBT condition, children completed the self-register using a paper-and-pencil procedure, while in the web platform condition, participants completed the self-register using an electronic personal digital assistant. Results showed the potential of SOM for analyzing the large amount of data necessary to study the acquisition of new habits in a childhood obesity treatment. Currently, the high prevalence of childhood obesity points to the need to develop strategies to manage a large number of data in order to design procedures adapted to personal characteristics and increase treatment efficacy

Impact of reducing sitting time in women with fibromyalgia and obesity: a randomized controlled trial

Background: Sitting time has negative effects on health, increasing the risk of obesity, osteoporosis, diabetes, and cancer. Thus, primary health care education interventions aimed to reduce sitting time and sedentary behavior could have beneficial effects on people’s health and wellbeing. The purpose of this study was to assess the effectiveness of an intervention based on reducing sitting time to decrease cardiometabolic risk on a sample of women diagnosed with fibromyalgia and moderate obesity. Methods: Randomized controlled trial to evaluate the effectiveness of an intervention to decrease cardiometabolic risk in 84 participants. Sedentary behavior was monitored using an accelerometer before and at 3-month follow-up. Results: Compared with the control group, body mass index decreased, and the number of steps taken increased, in the intervention group 3 months after the intervention. No significant differences were found in the rest of the variables measured. Conclusion: The intervention group decreased sitting time after the intervention. Group activities and support from primary care may be useful to improve treatment adherence

Association between life skills and academic performance in adolescents in the autonomous community of aragon (Spain)

Background: Learning and socio-emotional development is promoted through the creation and nurturing of an optimal school climate. This study aims to analyze the relationship between life skills and academic performance in a large sample of adolescents from the autonomous community of Aragón (Spain). Methods: A cross-sectional study was conducted on the life skills and academic performance of a sample of 7th and 8th grade middle school students during the academic year 2018–2019. A sample of 43 middle schools were randomly selected; the final sample comprised 1745 students. The following data were collected through an anonymized, previously validated questionnaire: sociodemographic variables, social skills, self-efficacy, affective balance, and academic performance. Results: We found a statistically significant association between life skills and academic performance (p < 0.001) in our sample. We also observed significant gender differences in life skills, with boys obtaining higher scores in cognitive skills and affective balance, and with girls achieving higher scores in social skills. Conclusion: We argue that life skills should be integrated into educational policies in order to improve the academic performance and health outcomes of students. © 2021 by the authors. Licensee MDPI, Basel, Switzerland