1,065 research outputs found
Non-affine geometrization can lead to nonphysical instabilities
Geometrization of dynamics consists of representing trajectories by geodesics
on a configuration space with a suitably defined metric. Previously, efforts
were made to show that the analysis of dynamical stability can also be carried
out within geometrical frameworks, by measuring the broadening rate of a bundle
of geodesics. Two known formalisms are via Jacobi and Eisenhart metrics. We
find that this geometrical analysis measures the actual stability when the
length of any geodesic is proportional to the corresponding time interval. We
prove that the Jacobi metric is not always an appropriate parametrization by
showing that it predicts chaotic behavior for a system of harmonic oscillators.
Furthermore, we show, by explicit calculation, that the correspondence between
dynamical- and geometrical-spread is ill-defined for the Jacobi metric. We find
that the Eisenhart dynamics corresponds to the actual tangent dynamics and is
therefore an appropriate geometrization scheme.Comment: Featured on the Cover of the Journal. 9 pages, 6 figures:
http://iopscience.iop.org/1751-8121/48/7/07510
Pay-as-bid pricing in combined pool / bilateral electricity markets
In the context of combined pool/bilateral operation of electricity markets, this paper compares two pricing strategies; pay-as-bid strategy defines three types of services: bilateral contract generation, transmission loss and congestion management required by the bilateral contracts, and pool demand generation including associated transmission loss and congestio
3rd International Conference on Advanced Research Methods and Analytics (CARMA 2020)
Research methods in economics and social sciences are evolving with the increasing availability of Internet and Big Data sources of information.As these sources, methods, and applications become more interdisciplinary, the 3rd International Conference on Advanced Research Methods and Analytics (CARMA) is an excellent forum for researchers and practitioners to exchange ideas and advances on how emerging research methods and sources are applied to different fields of social sciences as well as to discuss current and future challenges.Doménech I De Soria, J.; Vicente Cuervo, MR. (2020). 3rd International Conference on Advanced Research Methods and Analytics (CARMA 2020). Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/149510EDITORIA
4th. International Conference on Advanced Research Methods and Analytics (CARMA 2022)
Research methods in economics and social sciences are evolving with the increasing availability of Internet and Big Data sources of information. As these sources, methods, and applications become more interdisciplinary, the 4th International Conference on Advanced Research Methods and Analytics (CARMA) is a forum for researchers and practitioners to exchange ideas and advances on how emerging research methods and sources are applied to different fields of social sciences as well as to discuss current and future challenges. Due to the covid pandemic, CARMA 2022 is planned as a virtual and face-to-face conference, simultaneouslyDoménech I De Soria, J.; Vicente Cuervo, MR. (2022). 4th. International Conference on Advanced Research Methods and Analytics (CARMA 2022). Editorial Universitat Politècnica de València. https://doi.org/10.4995/CARMA2022.2022.1595
Antonio José Ruiz de Padrón : sacerdote, diputado, ilustrado y liberal
NaciĂł este ilustre canario en la Villa de San Sebastián de La Gomera, el dĂa 9 de noviembre de 1757, en una vivienda, aĂşn conservada, de la actualmente conocida como Calle del Medio
Perinatal and parental determinants of childhood overweight in 6-12 years old children
Introduction & aims: The identification of determinants of childhood overweight is crucial to early diagnosis and prevention. The aim of this study was to assess perinatal and parental related risk factors concerning children for having excessive body weight.
Methods: Cross-sectional study involving 3,101 children participating in the programme “Alimenta su salud” conducted in Castilla-La Mancha (Spain). Anthropometric and sociodemographic data were obtained from a general questionnaire. Analysed factors as potential predictors of childhood overweight were sex, age, birth weight, infant feeding, number of siblings, as well as parental marital status, educational level and obesity. Prevalence of overweight stratified by potential determinants was assessed. Univariate and multivariate logistic regression analyses were used to examine the associations between variables and the likelihood of being overweight.
Results: The overweight prevalence (including obesity) was 30.3% in boys and 28.3% in girls, according to the IOTF criteria. Higher rates in younger subjects and some gender differences were observed. Parental obesity was the most important predictive variable for childhood overweight in both sexes and birth weight over 3,500 g in girls (OR 1.8, 95% CI 1.3-2.3). Having one or more siblings (OR 0.7, 95% CI 0.5-0.9) and higher paternal education (OR 0.8, 95% CI 0.6-0.9) in boys, and older age in girls (OR 0.7, 95% CI 0.5-.09), resulted protective factors against childhood overweight. No independent effects of marital status, maternal education and infant feeding patterns on childhood excess weight were identified.
Conclusions: Perinatal and parental factors could contribute to predict the risk of being overweight/obese in children aged 6 to 12 years, which should be considered when formulating obesity prevention and intervention strategies, stressing the importance of targeting obese parents with young children
Age- and stress-associated C. elegans granulins impair lysosomal function and induce a compensatory HLH-30/TFEB transcriptional response.
The progressive failure of protein homeostasis is a hallmark of aging and a common feature in neurodegenerative disease. As the enzymes executing the final stages of autophagy, lysosomal proteases are key contributors to the maintenance of protein homeostasis with age. We previously reported that expression of granulin peptides, the cleavage products of the neurodegenerative disease protein progranulin, enhance the accumulation and toxicity of TAR DNA binding protein 43 (TDP-43) in Caenorhabditis elegans (C. elegans). In this study we show that C. elegans granulins are produced in an age- and stress-dependent manner. Granulins localize to the endolysosomal compartment where they impair lysosomal protease expression and activity. Consequently, protein homeostasis is disrupted, promoting the nuclear translocation of the lysosomal transcription factor HLH-30/TFEB, and prompting cells to activate a compensatory transcriptional program. The three C. elegans granulin peptides exhibited distinct but overlapping functional effects in our assays, which may be due to amino acid composition that results in distinct electrostatic and hydrophobicity profiles. Our results support a model in which granulin production modulates a critical transition between the normal, physiological regulation of protease activity and the impairment of lysosomal function that can occur with age and disease
Transcription factor NFE2L2/NRF2 modulates chaperone-mediated autophagy through the regulation of LAMP2A
Chaperone-mediated autophagy (CMA) is a selective degradative process for cytosolic proteins that contributes to the maintenance of proteostasis. The signaling mechanisms that control CMA are not fully understood but might involve response to stress conditions including oxidative stress. Considering the role of CMA in redoxtasis and proteostasis, we sought to determine if the transcription factor NFE2L2/NRF2 (nuclear factor, erythroid derived 2, like 2) has an impact on CMA modulation. In this work, we identified and validated 2 NFE2L2 binding sequences in the LAMP2 gene and demonstrated in several human and mouse cell types that NFE2L2 deficiency and overexpression was linked to reduced and increased LAMP2A levels, respectively. Accordingly, lysosomal LAMP2A levels were drastically reduced in nfe2l2-knockout hepatocytes, which also displayed a marked decrease in CMA activity. Oxidant challenge with paraquat or hydrogen peroxide, or pharmacological activation of NFE2L2 with sulforaphane or dimethyl fumarate also increased LAMP2A levels and CMA activity. Overall, our study identifies for the first time basal and inducible regulation of LAMP2A, and consequently CMA activity, by NFE2L2. Abbreviations: ACTB: actin, beta, ARE: antioxidant response element; ATG5: autophagy related 5; BACH1: BTB domain and CNC homolog 1; ChIP: chromatin immunoprecipitation; CMA: chaperone-mediated autophagy; DHE: dihydroethidium; DMF: dimethyl fumarate; ENCODE: Encyclopedia of DNA elements at the University of California, Santa Cruz; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GBA: glucosylceramidase beta; GFP: green fluorescent protein; HMOX1: heme oxygenase 1; H2O2: hydrogen peroxide; HSPA8/HSC70: heat shock protein family A (Hsp70) member 8; KEAP1: kelch like ECH associated protein 1; LAMP2A: lysosomal associated membrane protein 2A; LAMP2B: lysosomal associated membrane protein 2B; LAMP2C: lysosomal associated membrane protein 2C; LAMP1: lysosomal associated membrane protein 1; MAFF: MAF bZIP transcription factor F; MAFK: MAF bZIP transcription factor K; NFE2L2/NRF2: nuclear factor, erythroid derived 2, like 2; NQO1: NAD(P)H quinone dehydrogenase 1; PQ: paraquat; PI: protease inhibitors; qRT-PCR: quantitative real-time polymerase chain reaction; RNASE: ribonuclease A family member; SFN: sulforaphane; SQSTM1/p62: sequestosome 1; TBP: TATA-box binding proteinThis paper was funded by the Spanish Ministry of Economy and Competitiveness under the grant SAF2016-76520-R and by grants from the National Institute of Health/National Institute on Aging P01 AG031782. M.P. is recipient of a FPU fellowship of Autonomous University of
Madrid. E.A. was supported by NIH/NIA AG038072 P&
Caregiving For and By Hispanic Elders: Perceptions of Four Generations of Women
So as to learn about the experiences of acculturation among older Hispanic women, four generations were interviewed about their ethnic identity, perceptions of gender equity in the home, life satisfaction, and beliefs regarding family caregiving responsibilities. Findings reveal general differences between hopes for, and experiences with, gender equity and in their self-identification as a member of a minority group and their perceptions of others toward them. Differences were also found among the four age groups of Hispanic women
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