2,585 research outputs found

    Aperture-free star formation rate of SDSS star-forming galaxies

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    Large area surveys with a high number of galaxies observed have undoubtedly marked a milestone in the understanding of several properties of galaxies, such as star-formation history, morphology, and metallicity. However, in many cases, these surveys provide fluxes from fixed small apertures (e.g. fibre), which cover a scant fraction of the galaxy, compelling us to use aperture corrections to study the global properties of galaxies. In this work, we derive the current total star formation rate (SFR) of Sloan Digital Sky Survey (SDSS) star-forming galaxies, using an empirically based aperture correction of the measured Hα\rm H\alpha flux for the first time, thus minimising the uncertainties associated with reduced apertures. All the Hα\rm H\alpha fluxes have been extinction-corrected using the Hα/HÎČ\rm H\alpha/H\beta ratio free from aperture effects. The total SFR for ∌\sim210,000 SDSS star-forming galaxies has been derived applying pure empirical Hα\rm H\alpha and Hα/HÎČ\rm H\alpha/H\beta aperture corrections based on the Calar Alto Legacy Integral Field Area (CALIFA) survey. We find that, on average, the aperture-corrected SFR is ∌\sim0.65dex higher than the SDSS fibre-based SFR. The relation between the SFR and stellar mass for SDSS star-forming galaxies (SFR--M⋆\rm M_\star) has been obtained, together with its dependence on extinction and Hα\rm H\alpha equivalent width. We compare our results with those obtained in previous works and examine the behaviour of the derived SFR in six redshift bins, over the redshift range 0.005≀z≀0.22\rm 0.005 \leq z\leq 0.22. The SFR--M⋆\rm M_\star sequence derived here is in agreement with selected observational studies based on integral field spectroscopy of individual galaxies as well as with the predictions of recent theoretical models of disc galaxies

    An Adaptive Observer-Based Controller Design for Active Damping of a DC Network with a Constant Power Load

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    © 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting /republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksThis article explores a nonlinear, adaptive controller aimed at increasing the stability margin of a direct-current (dc), small-scale, electrical network containing an unknown constant power load (CPL). Due to its negative incremental impedance, this load reduces the effective damping of the network, which may lead to voltage oscillations and even to voltage collapse. To overcome this drawback, we consider the incorporation of a controlled dc-dc power converter in parallel with the CPL. The design of the control law for the converter is particularly challenging due to the existence of unmeasured states and unknown parameters. We propose a standard input-output linearization stage, to which a suitably tailored adaptive observer is added. The good performance of the controller is validated through experiments on a small-scale network.Peer ReviewedPostprint (author's final draft

    Population Density and Reproductive Seasonality of Tryonia cheatumi (Gastropoda: Cochliopidae), the Phantom Tryonia

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    We studied population density, population size, and reproductive seasonality of the Phantom Tryonia, Tryonia cheatumi (Pilsbry, 1935). This endangered freshwater snail is found only in the San Solomon Spring system, a cienega, or karst-based, arid-land freshwater spring system, in western Texas, USA. We sampled populations at seven locations in the system seasonally over a 2-yr period. San Solomon Spring, the system\u27s largest spring and modified into a swimming pool, had the largest population of T. cheatumi, with an estimated 49 million individuals and a mean density as high as 23,626 ± 39,030 (individuals/m2 ± SD). There were seasonal differences in mean density (up to 25-fold) and median snail size at all sites, but consistent seasonal patterns of mean density or size were not observed. Median snail size among samples was not related to water temperature, and juveniles were present in most samples in all seasons. These results support continuous, aseasonal reproduction, as expected in thermally stable habitats, but differences in median size and mean density among seasons and sites suggest that other factors affect reproduction and seasonal variation in population size of T. cheatumi

    Comparative efficacy between atorvastatin and rosuvastatin in the prevention of cardiovascular disease recurrence

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    Background: There is no randomized clinical trials with recurrence of atherosclerotic cardiovascular disease (ASCVD) as a major outcome with rosuvastatin. In order to analyze potential differences in the clinical response to atorvastatin and rosuvastatin in secondary ASCVD prevention, we have analyzed the clinical evolution of those subjects of the Dyslipemia Registry of the Spanish Society of Arteriosclerosis (SEA) who at the time of inclusion in the Registry had already suffered an ASCVD. Methods: This observational, retrospective, multicenter, national study was designed to determine potential differences between the use of atorvastatin and rosuvastatin in the ASCVD recurrence. Three different follow-up start-times were performed: time of inclusion in the registry; time of first event if this occurred after 2005, and time of first event without date restriction. Results: Baseline characteristics were similar between treatment groups. Among atorvastatin or rosuvastatin users, 89 recurrences of ASCVD were recorded (21.9%), of which 85.4% were coronary. At the inclusion of the subject in the registry, 345 participants had not suffered a recurrence yet. These 345 subjects accumulated 1050 person-years in a mean follow-up of 3 years. Event rates were 2.73 (95% CI: 1.63, 4.25) cases/100 person-years and 2.34 (95% CI: 1.17, 4.10) cases/100 person-years in the atorvastatin and rosuvastatin groups, respectively. There were no statistically significant differences between the two groups independently of the follow-up start-time. Conclusions: This study does not find differences between high doses of rosuvastatin and atorvastatin in the recurrence of ASCVD, and supports their use as clinically equivalent in secondary prevention of ASCVD

    Growth of Chlorella vulgaris and Nannochloris oculata in effluents of Tilapia farming for the production of fatty acids with potential in biofuels

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    The use of microalgae in wastewater treatment and its biotechnological exploitation for the production of biofuels is a potential environmental application. Some species of microalgae are notable due to their lipid composition and fatty acid profile suitable for biofuel production. During the present study, a factorial 23 experimental design was conducted, which assessed three factors: i) two species of microalgae (Chlorella vulgaris and Nannochloris oculata), ii) two types of culture media [wastewater of tilapia farming (WTF) and bold’s basal medium (BB)], and iii) two types of lighting (multi-LED lamps and white light). Microalgae were inoculated in photobioreactors in 6 L of medium (WTF or BBM) at an initial concentration of 1.0 × 106 cells ml-1 at 20 ± 2°C. The highest average cell density as well as the highest productivity of biomass observed in the treatments was C. vulgaris treatment in BBM and multi-LED lighting (8.83 × 107 cells ml-1 and 0.0854 g l-1 d-1, respectively). Although the majority of lipid productivity was obtained in the exponential phase of N. oculata cultivated in multi-LEDs in both treatments (BBM with 58% and WTF with 52%), cultivation of both species was generally maintained in WTF and were those that presented the major lipid productivity (2-18 mg l-1 d-1) in comparison with those cultivated in BBM. Palmitic, stearic, oleic, linoleic, linolenic and eicosanoic (C16–C20) fatty acids were present in both species of microalgae in concentrations between 26 and 74%. Based on the results of the present study, we conclude that cultivation of N. oculata and/or C. vulgaris in WTF illuminated with multi-LEDs is an economic and sustainable alternative for biodiesel production because it can represent up to 58% of lipids with a fatty acid profile optimal up to 74% of the total fatty acids.Key words: Chlorella vulgaris, Nannochloris oculata, production of fatty acids, wastewater of tilapia farming, production of biofuels

    Effect of tannins from tropical plants on methane production from ruminants: A systematic review

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    Methane (CH4) is a greenhouse gas generated during the feed fermentation processes in the rumen. However, numerous studies have been conducted to determine the capacity of plant secondary metabolites to enhance ruminal fermentation and decrease CH4 production, especially those plants rich in tannins. This review conducted a descriptive analysis and meta-analysis of the use of tannin-rich plants in tropical regions to mitigate CH4 production from livestock. The aim of this study was to analyse the effect of tannins supplementation in tropical plants on CH4 production in ruminants using a meta-analytic approach and the effect on microbial population. Sources of heterogeneity were explored using a meta-regression analysis. Final database was integrated by a total of 14 trials. The ‘meta’ package in R statistical software was used to conduct the meta-analyses. The covariates defined a priori in the current meta-regression were inclusion level, species (sheep, beef cattle, dairy cattle, and cross-bred heifers) and plant. Results showed that supplementation with tropical plants with tannin contents have the greatest effects on CH4 mitigation. A negative relationship was observed between the level of inclusion and CH4 emission (−0.09), which means that the effect of CH4 mitigation is increasing as the level of tannin inclusion is higher. Therefore, less CH4 production will be obtained when supplementing tropical plants in the diet with a high dose of tannins

    The application of a mechanistic model to analyze the factors that affect the lactation curve parameters of dairy sheep in Mexico

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    Pollott́s mechanistic model has been designed to describe lactation curve parameters based on the known biology of milk production and can be useful for analyzing the factors that affect this process. A total of 553 lactations (9956 weekly test-day records) of crossbred dairy sheep from four commercial farms located in Mexico, were analyzed to investigate environmental factors that influenced lactation curve parameters, using Pollott’s 5-parameter additive model. This model was fitted to each lactation using an iterative nonlinear procedure. The estimated parameters were maximum milk secretion potential (MSmax), relative rate of increase in cell differentiation (GR), maximum secretion loss (MSLmax), relative rate of decline in cell numbers (DR) and the proportion of parenchyma cells dead at parturition. A general linear model procedure was used to determine the effect of type of lambing, lambing number, flock and lambing season on total lactation milk yield (TMY), lactation length and estimated parameters of the Pollott model. Ewes had an average milk yield of 74.4 L with an average lactation length of 140 days. Flock had a significant (P < 0.05) effect on most of the analyzed traits, which can be explained by the different farmƛ management practices. The TMY were significantly (P = 0.005) higher for twin-lambing than single-lambing lactations. Sheep in their first lambing had lower TMY than those in their fourth lambing (P = 0.01), possibly explained by the lower values of MSmax (2.85 vs. 5.3 L) and the decrease in DR throughout life (P = 0.03). However, the relative GR was greatest (P = 0.04) during first lambing and then decreased as lambing number increased. Both lambing number and type of lambing also affected milk yield. The parameters of the Pollott model can be useful to explain, with a biological approximation, the dynamics of differentiation, secretion and death of mammary cells in dairy sheep

    Easy-To-Synthesize Spirocyclic Compounds Possess Remarkable in Vivo Activity against Mycobacterium tuberculosis

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    Society urgently needs new, effective medicines for the treatment of tuberculosis. To kick-start the required hit-to-lead campaigns, the libraries of pharmaceutical companies have recently been evaluated for starting points. The GlaxoSmithKline (GSK) library yielded many high-quality hits, and the associated data were placed in the public domain to stimulate engagement by the wider community. One such series, the spiro compounds, are described here. The compounds were explored by a combination of traditional in-house research and open source methods. The series benefits from a particularly simple structure and a short associated synthetic chemistry route. Many members of the series displayed striking potency and low toxicity, and highly promising in vivo activity in a mouse model was confirmed with one of the analogues. Ultimately the series was discontinued due to concerns over safety, but the associated data remain public domain, empowering others to resume the series if the perceived deficiencies can be overcome

    Virtual reality exercise intradialysis to improve physical function: A feasibility randomized trial

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    [EN] Objective The main objective of this investigation was to assess feasibility of conducting a future RCT with an intradialysis non-immersive virtual reality exercise intervention. The secondary aim was to explore the impact of either conventional or VR exercise on physical function. Design Feasibility randomized trial. Participants Eighteen subjects who participated in a 16-week intradialysis combined exercise program. Interventions The program lasted four additional weeks of either combined exercise or virtual reality exercise. Main outcome measures Physical function was measured through several reliable tests (sit-to-stand-to-sit tests 10 and 60, gait speed, one-leg heel-rise tests, and 6-minute walk test) at baseline, after 16 weeks of intradialysis combined exercise and by the end of four additional weeks of exercise. Adherence to the exercise programs was registered. Results There was a significant time effect, so that physical function improved in both groups. By the end of the 20 weeks, function improved as measured through the sit-to-stand-to-sit tests 10 and 60, gait speed, one-leg heel-rise left leg, and the 6-minute walk test. Changes that did not occur due to error in the test were seen after 20 weeks were achieved in the sit-to-stand-to-sit test 60, gait speed, one-leg heel-rise test for the left leg, and 6-minute walking test. Conclusion Virtual reality was a feasible intervention. Both interventions improved physical function. Adherence was not significantly different between groups.Universidad Cardenal Herrera-CEU, CEU Universities, Valencia, Spain, Grant/Award Number: Consolidacion de Indicadores CEU-UCH 2016-2017/ISegura-Orti, E.; Perez-Dominguez, B.; Ortega-PĂ©rez De Villar, L.; Melendez-Oliva, E.; MartĂ­nez-Gramaje, J.; GarcĂ­a-Maset, R.; Gil-GĂłmez, J. (2019). Virtual reality exercise intradialysis to improve physical function: A feasibility randomized trial. Scandinavian Journal of Medicine and Science in Sports. 29(1):89-94. https://doi.org/10.1111/sms.13304S8994291Segura-OrtĂ­, E., Gordon, P. L., Doyle, J. W., & Johansen, K. L. (2017). Correlates of Physical Functioning and Performance Across the Spectrum of Kidney Function. Clinical Nursing Research, 27(5), 579-596. doi:10.1177/1054773816689282Segura-Orti, E., & Johansen, K. L. (2010). Exercise in End-Stage Renal Disease. Seminars in Dialysis, 23(4), 422-430. doi:10.1111/j.1525-139x.2010.00766.xDelgado, C., & Johansen, K. L. (2011). Barriers to exercise participation among dialysis patients. Nephrology Dialysis Transplantation, 27(3), 1152-1157. doi:10.1093/ndt/gfr404Heiwe, S., & Tollin, H. (2012). Patients’ perspectives on the implementation of intra-dialytic cycling—a phenomenographic study. Implementation Science, 7(1). doi:10.1186/1748-5908-7-68Konstantinidou, E., Koukouvou, G., Kouidi, E., Deligiannis, A., & Tourkantonis, A. (2002). Exercise training in patients with end-stage renal disease on hemodialysis: Comparison of three rehabilitation programs. Journal of Rehabilitation Medicine, 34(1), 40-45. doi:10.1080/165019702317242695Corbetta, D., Imeri, F., & Gatti, R. (2015). Rehabilitation that incorporates virtual reality is more effective than standard rehabilitation for improving walking speed, balance and mobility after stroke: a systematic review. Journal of Physiotherapy, 61(3), 117-124. doi:10.1016/j.jphys.2015.05.017Peruzzi, A., Cereatti, A., Della Croce, U., & Mirelman, A. (2016). Effects of a virtual reality and treadmill training on gait of subjects with multiple sclerosis: a pilot study. Multiple Sclerosis and Related Disorders, 5, 91-96. doi:10.1016/j.msard.2015.11.002Brien, M., & Sveistrup, H. (2011). An Intensive Virtual Reality Program Improves Functional Balance and Mobility of Adolescents With Cerebral Palsy. Pediatric Physical Therapy, 23(3), 258-266. doi:10.1097/pep.0b013e318227ca0fOrtega‐PĂ©rez de VillarL PĂ©rez‐ DomĂ­nguezB Segura‐OrtĂ­E et al.Use of virtual reality game as part of exercise program for chronic kidney disease patients undergoing haemodialysis.2015.Cho, H., & Sohng, K.-Y. (2014). The Effect of a Virtual Reality Exercise Program on Physical Fitness, Body Composition, and Fatigue in Hemodialysis Patients. Journal of Physical Therapy Science, 26(10), 1661-1665. doi:10.1589/jpts.26.1661OrtegaL.Comparison of two exercise programs for hemodialysis patients intradialysis vs home based program. absolute and relative reliability of physical performance[tesis doctoral]. Universidad CEU Cardenal Herrera. Facultad de Ciencias de la Salud;2017.Guralnik, J. M., Ferrucci, L., Simonsick, E. M., Salive, M. E., & Wallace, R. B. (1995). Lower-Extremity Function in Persons over the Age of 70 Years as a Predictor of Subsequent Disability. New England Journal of Medicine, 332(9), 556-562. doi:10.1056/nejm199503023320902Segura-OrtĂ­, E., & MartĂ­nez-Olmos, F. J. (2011). Test-Retest Reliability and Minimal Detectable Change Scores for Sit-to-Stand-to-Sit Tests, the Six-Minute Walk Test, the One-Leg Heel-Rise Test, and Handgrip Strength in People Undergoing Hemodialysis. Physical Therapy, 91(8), 1244-1252. doi:10.2522/ptj.20100141Segura-OrtĂ­, E. (2017). Fisioterapia sobre ejercicio en pacientes en hemodiĂĄlisis. Fisioterapia, 39(4), 137-139. doi:10.1016/j.ft.2017.05.003Bohm, C., Stewart, K., Onyskie-Marcus, J., Esliger, D., Kriellaars, D., & Rigatto, C. (2014). Effects of intradialytic cycling compared with pedometry on physical function in chronic outpatient hemodialysis: a prospective randomized trial. Nephrology Dialysis Transplantation, 29(10), 1947-1955. doi:10.1093/ndt/gfu248KOUFAKI, P., NASH, P. F., & MERCER, T. H. (2002). Assessing the efficacy of exercise training in patients with chronic disease. Medicine & Science in Sports & Exercise, 34(8), 1234-1241. doi:10.1097/00005768-200208000-00002Cappy, C. S., Jablonka, J., & Schroeder, E. T. (1999). The effects of exercise during hemodialysis on physical performance and nutrition assessment. Journal of Renal Nutrition, 9(2), 63-70. doi:10.1016/s1051-2276(99)90002-xHeadley, S., Germain, M., Mailloux, P., Mulhern, J., Ashworth, B., Burris, J., 
 Jones, M. (2002). Resistance training improves strength and functional measures in patients with end-stage renal disease. American Journal of Kidney Diseases, 40(2), 355-364. doi:10.1053/ajkd.2002.34520Painter, P., Carlson, L., Carey, S., Paul, S. M., & Myll, J. (2000). Low-functioning hemodialysis patients improve with exercise training. American Journal of Kidney Diseases, 36(3), 600-608. doi:10.1053/ajkd.2000.16200Segura-OrtĂ­, E., Kouidi, E., & LisĂłn, J. F. (2009). Effect of resistance exercise during hemodialysis on physical function and quality of life: randomized controlled trial. Clinical Nephrology, 71(05), 527-537. doi:10.5414/cnp71527Esteve SimĂł, V., JunquĂ©, A., Fulquet, M., Duarte, V., Saurina, A., Pou, M., 
 RamĂ­rez de Arellano, M. (2014). Complete Low-Intensity Endurance Training Programme in Haemodialysis Patients: Improving the Care of Renal Patients. Nephron Clinical Practice, 128(3-4), 387-393. doi:10.1159/000369253Johansen, K. L., Painter, P. L., Sakkas, G. K., Gordon, P., Doyle, J., & Shubert, T. (2006). Effects of Resistance Exercise Training and Nandrolone Decanoate on Body Composition and Muscle Function among Patients Who Receive Hemodialysis: A Randomized, Controlled Trial. Journal of the American Society of Nephrology, 17(8), 2307-2314. doi:10.1681/asn.2006010034Tao, X., Chow, S. K. Y., & Wong, F. K. (2017). The effects of a nurse-supervised home exercise programme on improving patients’ perceptions of the benefits and barriers to exercise: A randomised controlled trial. Journal of Clinical Nursing, 26(17-18), 2765-2775. doi:10.1111/jocn.13798Rossi, A. P., Burris, D. D., Lucas, F. L., Crocker, G. A., & Wasserman, J. C. (2014). Effects of a Renal Rehabilitation Exercise Program in Patients with CKD: A Randomized, Controlled Trial. Clinical Journal of the American Society of Nephrology, 9(12), 2052-2058. doi:10.2215/cjn.11791113Boone, A. E., Foreman, M. H., & Engsberg, J. R. (2017). Development of a novel virtual reality gait intervention. Gait & Posture, 52, 202-204. doi:10.1016/j.gaitpost.2016.11.025Orcy, R. B., Dias, P. S., Seus, T. L., Barcellos, F. C., & Bohlke, M. (2012). Combined Resistance and Aerobic Exercise is Better than Resistance Training Alone to Improve Functional Performance of Haemodialysis Patients - Results of a Randomized Controlled Trial. Physiotherapy Research International, 17(4), 235-243. doi:10.1002/pri.1526Oliveros R, M. S., Avendaño, M., Bunout, D., Hirsch, S., De La Maza, M. P., Pedreros, C., & MĂŒller, H. (2011). Estudio piloto sobre entrenamiento fĂ­sico durante hemodiĂĄlisis. Revista mĂ©dica de Chile, 139(8), 1046-1053. doi:10.4067/s0034-98872011000800010Silva, S. F. da, Pereira, A. A., Silva, W. A. H. da, SimĂŽes, R., & Barros Neto, J. de R. (2013). Physical therapy during hemodialyse in patients with chronic kidney disease. Jornal Brasileiro de Nefrologia, 35(3), 170-176. doi:10.5935/0101-2800.20130028Bulckaen, M., Capitanini, A., Lange, S., Caciula, A., Giuntoli, F., & Cupisti, A. (2011). Implementation of exercise training programs in a hemodialysis unit: effects on physical performance. Journal of Nephrology, 24(6), 790-797. doi:10.5301/jn.2011.6386Cook, S. A., MacLaughlin, H., & Macdougall, I. C. (2007). A structured weight management programme can achieve improved functional ability and significant weight loss in obese patients with chronic kidney disease. Nephrology Dialysis Transplantation, 23(1), 263-268. doi:10.1093/ndt/gfm511PĂ©rezDF.ComparaciĂłn de los efectos de un programa de ejercicio intradiĂĄlisis frente a un programa de ejercicio domiciliario[tesis doctoral]. Universidad CEU Cardenal Herrera Facultad de Ciencias de la Salud;2017.Wilkinson, T. J., Shur, N. F., & Smith, A. C. (2016). «Exercise as medicine» in chronic kidney disease. Scandinavian Journal of Medicine & Science in Sports, 26(8), 985-988. doi:10.1111/sms.1271
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