161 research outputs found
Hotspot detection and a nonstationary process variance function estimation
A two-stage spatial sampling design for detecting contaminated areas is proposed for effective decontamination planning. A two-stage design has a higher or equal hotspot detection probability than a one-stage design under fixed budget constraints. The proposed design uses the expected relative size of the contaminated area and the overall sampling rate as the two control variables in determining an optimal sample splitting proportion for a two-stage design. Results are shown through simulation studies and theoretical derivation.
Many spatial processes exhibit nonstationary features. We estimate a variance function from a single process observation where the errors are nonstationary and correlated. We assume that the mean process is smooth and that the error process is a product of a smooth variance function and a second-order stationary process. A difference-based approach for a one-dimensional nonstationary process is developed along with a bandwidth selection method which takes into account the error dependence structure. The asymptotic properties of the estimator are investigated, and the estimation results are compared to that of a local-likelihood approach proposed by Anderes and Stein (2011). Simulation study shows that our method has a smaller integrated MSE, fixes the boundary bias problem, and requires far less computing time as the evaluation of likelihood with matrix inversion is not necessary. For a two-dimensional nonstationary process with correlated errors there are a few practical guides for selecting a difference filter of its shape, scale, and weight depending on the degree of correlation in the data. When the data is strongly correlated, a symmetric weighting scheme is preferred; and when the data is weakly correlated or independent, the Hall-Kay-Titterington (1991) weight is preferred. Also a compact filter would minimize introducing bias. The best filter configuration is a three-node line configuration with directional rotation and averaging
A new approach to the space–time analysis of big data: application to subway traffic data in Seoul
A prevalent type of big data is in the form of space–time measurements. Cyclostationary empirical orthogonal function (CSEOF) analysis is introduced as an efficient and valuable technique to interpret space–time structure of variability in a big dataset. CSEOF analysis is demonstrated to be a powerful tool in understanding the space–time structure of variability, when data exhibits periodic statistics in time. As an example, CSEOF analysis is applied to the hourly passenger traffic on Subway Line #2 of Seoul, South Korea during the period of 2010–2017. The first mode represents the weekly cycle of subway passengers and captures the majority (~ 97%) of the total variability. The corresponding loading vector exhibits a typical weekly pattern of subway passengers as a function of time and the locations of subway stations. The associated principal component time series shows that there are two occasions of significant reduction in the amplitude of the weekly activity in each year; these reductions are associated with two major holidays—lunar New Year and Fall Festival (called Chuseok in Korea). The second and third modes represent daily contrasts in a week and are associated with taking extra days off before or after holidays. The fourth mode exhibits an interesting upward trend, which represents a general decrease in the number of subway passengers during weekdays except for Wednesday and an increase over the weekends.This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government(MSIP) (No. 2016R1A2B4008237)
Loss of the ciliary protein Chibby1 in mice leads to exocrine pancreatic degeneration and pancreatitis
Primary cilia protrude from the apical surface of many cell types and act as a sensory organelle that regulates diverse biological processes ranging from chemo- and mechanosensation to signaling. Ciliary dysfunction is associated with a wide array of genetic disorders, known as ciliopathies. Polycystic lesions are commonly found in the kidney, liver, and pancreas of ciliopathy patients and mouse models. However, the pathogenesis of the pancreatic phenotype remains poorly understood. Chibby1 (Cby1), a small conserved coiled-coil protein, localizes to the ciliary base and plays a crucial role in ciliogenesis. Here, we report that Cby1-knockout (KO) mice develop severe exocrine pancreatic atrophy with dilated ducts during early postnatal development. A significant reduction in the number and length of cilia was observed in Cby1-KO pancreta. In the adult Cby1-KO pancreas, inflammatory cell infiltration and fibrosis were noticeable. Intriguingly, Cby1-KO acinar cells showed an accumulation of zymogen granules (ZGs) with altered polarity. Moreover, isolated acini from Cby1-KO pancreas exhibited defective ZG secretion in vitro. Collectively, our results suggest that, upon loss of Cby1, concomitant with ciliary defects, acinar cells accumulate ZGs due to defective exocytosis, leading to cell death and progressive exocrine pancreatic degeneration after birth
Diagnostic Profiles and Clinical Characteristics of Youth Referred to a Pediatric Mood Disorders Clinic
The current study examined the diagnostic profiles and clinical characteristics of youth (ages 6–18) referred for diagnostic evaluation to a pediatric mood disorders clinic that specialized in early-onset bipolar disorder
Prácticas docentes para creatividad en la universidad: estudio en Portugal y Brasil
Creativity is nowadays seen as an essential feature in higher education. Nevertheless, there is a discrepancy between the need for creativity and what higher education classrooms provide. This study assessed the perceptions of 1599 higher education students from two countries (1059 Brazilian and 540 Portuguese students), from two academic domains (Sciences and Technologies – Sc&T; Social Sciences, Arts, and Humanities – SScA&H), about the presence of creativity in their teachers’ instruction and evaluation practices. The study’s findings evidence interactive effects between the variables country and academic domain for most of the assessed factors: encouragement of new ideas, climate for the expression of ideas, and interest in students’ learning. Brazilian Sc&T students presented more negative perceptions of their classroom environments when compared to SScA&H students; Portuguese students showed opposite patterns
of results. Some hypothetical explanations are discussed and future directions for research are presented.Criatividade é atualmente tomada como aspecto essencial na Educação Superior. Há, contudo, discrepância entre a necessidade
de criatividade e o que a universidade proporciona. Este estudo avaliou percepções de 1599 alunos universitários de dois países (1059
brasileiros e 540 portugueses), de duas áreas curriculares (Ciências e Tecnologias – Sc&T; Ciências Sociais, Artes e Humanidades – SscA&H)
sobre a presença de criatividade nas práticas docentes, instrucionais e avaliativas, de que são alvo. Os resultados mostraram efeitos
interativos significativos entre as variáveis país e área curricular para a maioria dos fatores avaliados: encorajamento de novas ideias,
clima para expressão de ideias e interesse pela aprendizagem dos alunos. Os estudantes brasileiros de Sc&T mostraram percepções mais
negativas da sala de aula, comparados com os de SScA&H; os alunos portugueses obtiveram padrões opostos nos resultados. Algumas
hipóteses explicativas são discutidas e são apresentadas orientações para pesquisa futura.La creatividad está actualmente considerada como aspecto esencial en la Educación Superior. Sin embargo, existe discrepancia
entre la necesidad de creatividad y lo que la universidad ofrece. Este estudio evaluó percepciones de 1.599 estudiantes universitarios
(1.059 de Brasil y 540 de Portugal) de dos áreas curriculares (Ciencia y Tecnología – Sc&T; Ciencias Sociales, Artes y Humanidades
– SscA&T) acerca de la presencia de creatividad en las prácticas docentes, instructivas y evaluativas dirigidas a ellos. Los resultados mostraron
efectos de interacción significativos entre las variables país y área curricular para la mayoría de los factores evaluados: fomento de
nuevas ideas, entorno para la expresión de ideas e interés en el aprendizaje del estudiante. Los estudiantes brasileños de Sc&T mostraron
percepciones más negativas de la clase en comparación con los de SSCA&H; los estudiantes portugueses obtuvieron patrones opuestos en
los resultados. Algunas hipótesis explicativas se discuten y se presentan directrices para investigación futura.Thermo Scientificinfo:eu-repo/semantics/publishedVersio
Rapidly measured indicators of recreational water quality and swimming-associated illness at marine beaches: a prospective cohort study
<p>Abstract</p> <p>Introduction</p> <p>In the United States and elsewhere, recreational water quality is monitored for fecal indicator bacteria to help prevent swimming-associated illnesses. Standard methods to measure these bacteria take at least 24 hours to obtain results. Molecular approaches such as quantitative polymerase chain reaction (qPCR) can estimate these bacteria faster, in under 3 hours. Previously, we demonstrated that measurements of the fecal indicator bacteria <it>Enterococcus </it>using qPCR were associated with gastrointestinal (GI) illness among swimmers at freshwater beaches. In this paper, we report on results from three marine beach sites.</p> <p>Methods</p> <p>We interviewed beach-goers and collected water samples at marine beaches affected by treated sewage discharges in Mississippi in 2005, and Rhode Island and Alabama in 2007. Ten to twelve days later, we obtained information about gastrointestinal, respiratory, eye, ear and skin symptoms by telephone. We tested water samples for fecal indicator organisms using qPCR and other methods.</p> <p>Results</p> <p>We enrolled 6,350 beach-goers. The occurrence of GI illness among swimmers was associated with a log<sub>10</sub>-increase in exposure to qPCR-determined estimates of fecal indicator organisms in the genus <it>Enterococcus </it>(AOR = 2.6, 95% CI 1.3-5.1) and order <it>Bacteroidales </it>(AOR = 1.9, 95% CI 1.3-2.9). Estimates of organisms related to <it>Clostridium perfringens </it>and a subgroup of organisms in the genus <it>Bacteroides </it>were also determined by qPCR in 2007, as was F+ coliphage, but relationships between these indicators and illness were not statistically significant.</p> <p>Conclusions</p> <p>This study provides the first evidence of a relationship between gastrointestinal illness and estimates of fecal indicator organisms determined by qPCR at marine beaches.</p
Decrease of CD68 Synovial Macrophages in Celastrol Treated Arthritic Rats
Rheumatoid arthritis (RA) is a chronic immune-mediated inflammatory disease characterized by cellular infiltration into the joints, hyperproliferation of synovial cells and bone damage. Available treatments for RA only induce remission in around 30% of the patients, have important adverse effects and its use is limited by their high cost. Therefore, compounds that can control arthritis, with an acceptable safety profile and low production costs are still an unmet need. We have shown, in vitro, that celastrol inhibits both IL-1β and TNF, which play an important role in RA, and, in vivo, that celastrol has significant anti-inflammatory properties. Our main goal in this work was to test the effect of celastrol in the number of sublining CD68 macrophages (a biomarker of therapeutic response for novel RA treatments) and on the overall synovial tissue cellularity and joint structure in the adjuvant-induced rat model of arthritis (AIA).FCT fellowship: (SFRH/BPD/92860/2013)
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