634 research outputs found
Pulsed light inactivation of mushroom polyphenol oxidase: a fluorometric and spectrophotometric study
Polyphenol oxidase (PPO) is one of the most important food enzymes, it is responsible for the browning of many foods. Pulsed light (PL) is a non-thermal method of food preservation that is able to inactivate PPO. The aim of this work was to gain insight into the mechanism of PPO inactivation by PL. To this, the kinetics of PPO inactivation by PL was measured, together with associated changes in tryptophan fluorescence, KI fluorescence quenching and turbidity; and results were analysed by parameter A and phase diagram methods. Enzyme inactivation followed the Weibull model. Tryptophan fluorescence decreased during PL treatment, as well as the parameter A, while Stern-Volmer constants increased and turbidity was constant. The phase diagram showed only two populated states. There was a high correlation between the loss of activity and parameter A. Results indicate that under the experimental conditions, the inactivation of PPO by PL is an all-or-none process where the enzyme progressively unfolds with no evidence of aggregation.Fundación Universitaria San Antonio de CartagenaCiencias de la Alimentació
Performance of Ti-15Mo alloy obtained by powder metallurgy route weakly alloyed with Fe/Cr elements
[EN] Ti-15Mo alloy can be an excellent choice as a biomaterial for prostheses. This is due to the combination of good mechanical properties and biocompatibility. The Mo is a stabilizing element of the ß phase, which provides a smaller elastic modulus, reducing the risk of stress shielding that induces bone resorption. The present work shows the effect of minor additions of Fe or Cr on flexural fracture toughness in Ti-15Mo alloys obtained by Powder Metallurgy. The electrochemical results indicated that the Ti-15Mo-1Cr, showed greater resistance to corrosion, related to lower ß grain size, less porosity content compared to the other conditions. As the Ti-15Mo-1Fe and Ti-15Mo-3Fe presented more porosity in their microstructure, the saline composition inside the pores is different in concentration and thus makes diffusion difficult compared to other regular and more homogeneous zones. Besides, was verified the effect of the large grain size that decrease the corrosion resistance of the Ti-15Mo-3Cr, demonstrated two influences in the corrosion resistance, porosity and grain size. Toughness decreases with the addition of both elements, more pronounced with Fe than Cr. It is related with lower densification, higher porosity and greater proportion of phase ¿ in grain boundary due to the higher resistance of diffusion of Mo in Ti when Fe is present, which leads to failure by brittle fracture at lower shear stresses.Correa Rossi, M.; López Navarro, P.; Vicente-Escuder, Á.; Amigó, V.; Segovia-López, F. (2022). Performance of Ti-15Mo alloy obtained by powder metallurgy route weakly alloyed with Fe/Cr elements. Social Science Research Network. 1-28. https://doi.org/10.2139/ssrn.400776212
City-scale monitoring of antibiotic resistance genes by digital PCR and metagenomics
Background Anthropogenic activities significantly contribute to the dissemination of antibiotic resistance genes (ARGs), posing a substantial threat to humankind. The development of methods that allow robust ARG surveillance is a long-standing challenge. Here, we use city-scale monitoring of ARGs by using two of the most promising cutting-edge technologies, digital PCR (dPCR) and metagenomics. Methods ARG hot-spots were sampled from the urban water and wastewater distribution systems. Metagenomics was used to provide a broad view of ARG relative abundance and richness in the prokaryotic and viral fractions. From the city-core ARGs in all samples, the worldwide dispersed sul2 and tetW conferring resistance to sulfonamide and tetracycline, respectively, were monitored by dPCR and metagenomics. Results The largest relative overall ARG abundance and richness were detected in the hospital wastewater and the WWTP inlet (up to ≈6,000 ARGs/Gb metagenome) with a large fraction of unclassified resistant bacteria. The abundance of ARGs in DNA and RNA contigs classified as viruses was notably lower, demonstrating a reduction of up to three orders of magnitude compared to contigs associated to prokaryotes. By metagenomics and dPCR, a similar abundance tendency of sul2 and tetW was obtained, with higher abundances in hospital wastewater and WWTP input (≈125–225 ARGs/Gb metagenome). dPCR absolute abundances were between 6,000 and 18,600 copies per ng of sewage DNA (≈105–7 copies/mL) and 6.8 copies/mL in seawater near the WWTP discharging point. Conclusions dPCR was more sensitive and accurate, while metagenomics provided broader coverage of ARG detection. While desirable, a reliable correlation of dPCR absolute abundance units into metagenomic relative abundance units was not obtained here (r2 < 0.4) suggesting methodological factors that introduce variability. Evolutionary pressure does not significantly select the targeted ARGs in natural aquatic environments.This project was supported with UAIND18-05 grant from the Program “Predoctoral Training in Collaboration with Companies” by the Office of the Vice President for Research, Development, and Innovation (University of Alicante). Funds were also provided by the Hospital Elche Crevillente Salud SL (ref. HOSPITALECLHE1-18Y)
Reducing test request for anti-thyroglobulin and anti-thyroid peroxidase antibodies: trends before and after interventions based on rejection rules and profile management
Introduction: The objective of this study was to identify trends in requests for anti-thyroid peroxidase antibodies (TPOab) and anti-thyroglobulin
antibodies (TGab) tests before and after applying set of interventions based on rejection rules and profile management.
Materials and methods: Trend analysis was made at semester time intervals (from May-October 2010 to May-October 2017), before and after
the intervention semester (May-October 2016). Number of tests (N) TPOab and TGab / 1000 total requests based on total N of both tests and total
N of biochemical analysis laboratory requests, was calculated. To find out where the interventions had more impact we distinguished N of requests
between Primary Care (PC) and Specialized Care (SC). A joinpoint regression analysis was used to determine time segments and time points in these
indicators where the trend changed.
Results: Trend analysis of the request of TPOab and TGab showed two clearly differentiated trend lines with a statistically significant Joinpoint (P
< 0.001) with an increase in each semester from May 2010 of 7.4% and 7.5% respectively, to the semester of the interventions where there was a
decrease of - 45% and - 61% located mainly in PC. Trend analysis in SC setting did not show any Joinpoint and any trend line.
Conclusions: Results showed that applied interventions enabled change of trend for TPOab and TGab test requests, especially in PC where the interventions
proved to be the most successful
El trabajo asalariado en la agricultura de la Baja Andalucía. Siglos XVIII y XIX
La existencia de grandes explotaciones agrarias en Andalucía Occidental, cuya producción se destinaba al mercado, implicaba la necesidad de una contratación masiva de mano de obra, dando lugar a una precoz proletarización de buena parte de la misma. Tan elevado era el número de trabajadores necesario para atender la demanda de trabajo de las citadas explotaciones que el mercado de trabajo local era incapaz de cubrirla por lo que había que recurrir a la contratación de trabajadores forasteros. La presencia de trabajadores locales y forasteros dio lugar a una segmentación de dicho mercado, en la que los trabajadores locales, tempranamente proletarizados, llevaban a cabo las faenas ordinarias de la explotación, mientras que los forasteros, generalmente campesinos humildes en sus áreas de procedencia, atendían las actividades con una mayor productividad marginal relacionadas con la recolección
Método no formal para la evaluación de la docencia aplicada al Grado de Ingeniería Informática
La evaluación de la docencia tiene diferentes objetivos.
En algunos casos pretende obtener un análisis
del funcionamiento de sus unidades docentes, tales
como las asignaturas, los departamentos o inclusos
las escuelas universitarias. En otros se quiere obtener
información sobre la labor del profesor en un determinado
periodo de tiempo o en la impartición de una
determinada materia. El método más comúnmente
utilizado para la evaluación de la docencia es la
realización de encuestas dirigidas a los alumnos.
Además de las debilidades que acostumbran a tener
los cuestionarios, éstos suelen dar resultados cuantitativos
que no permiten extraer con claridad información
que pueda suponer una evaluación formativa que
sirva al profesor para mejorar la calidad de su docencia.
En este artículo se presenta una propuesta para una
evaluación docente de una asignatura proporcionando
información cualitativa relevante para que el profesor
pueda conocer sus puntos débiles y fuertes así como
plantear acciones de mejora de cara a próximos
cursos académicos.
Esta técnica, que inicialmente se aplicó con anterioridad
en el Máster de Formación del Profesorado,
actualmente se ha probado con éxito en diversos
cursos del Grado en Ingeniería Informática, con unos
resultados orientados a la mejora continua y valorados
muy positivamente por los profesores.SUMMARY -- The evaluation of teaching has different objectives.
In some cases, the underlying objective is to obtain an
analysis of how effectively the teaching units, such as
subjects, departments or even entire universities,
work. In other cases the goal is to obtain information
on the teaching capacity of a professor in a determined
period of time or on a specific subject. Surveys,
completed by students, continue to be the most
commonly-used evaluation method for teaching.
Apart from weak points found in these surveys, we
should be aware of the fact that they only give quantitative
results which do not enable us to extract specific
information that could provide a more teachingfocused
evaluation. Such information could be used
to help teachers improve the quality of their teaching.
This article presents a proposal to evaluate the teaching
of a subject by providing qualitative information
which enables teachers to see both their weak and
strong points in order to plan improvements for future
courses.
This technique, which was initially applied in the
Master in Teacher Training, has since been successfully
tested on different courses in the Computer
Engineering Degree and the results, which will clearly
foment the process of continuous improvement,
have been well received by the teaching staff
El mercado de trabajo en la Andalucía latifundista del Antiguo Régimen: ¿intervencionismo o contratación?
Casi todos los autores coinciden al afirmar que el mercado de trabajo agrícola en el Antiguo Régimen estaba sujeto a una fuerte intervención por parte de las autoridades estatales y locales. Si bien los textos legales y jurídicos de la época reflejan dicha intervención, ello no impidió que quedase un amplio margen para la regulación del mercado mediante acuerdos entre los agentes -empresarios y trabajadores. En Andalucía estos acuerdos se plasmaron con frecuencia en contratos de trabajo firmados ante notario, que regulaban la realización de diversas faenas agrícolas, destacando las de recolección, especialmente la siega de cereales. El análisis de los libros de cuentas de las grandes explotaciones agrarias de la época, nos permite comprobar la gran flexibilidad que tuvo el mercado de trabajo agrícola andaluz en el Antiguo Régimen gracias a los citados contratos
Probabilistic analysis of random nonlinear oscillators subject to small perturbations via probability density functions: Theory and computing
[EN] We study a class of single-degree-of-freedom oscillators whose restoring function is affected by small nonlinearities and excited by stationary Gaussian stochastic processes. We obtain, via the stochastic perturbation technique, approximations of the main statistics of the steady state, which is a random variable, including the first moments, and the correlation and power spectral functions. Additionally, we combine this key information with the principle of maximum entropy to construct approximations of the probability density function of the steady state. We include two numerical examples where the advantages and limitations of the stochastic perturbation method are discussed with regard to certain general properties that must be preservedThis work has been supported by the Spanish Ministerio de Economia, Industria y Competitividad (MINECO), the Agencia Estatal de Investigacion (AEI), and Fondo Europeo de Desarrollo Regional (FEDER UE) Grant PID2020-115270GB-I00. The authors express their deepest thanks and respect to the reviewers for their valuable commentsCortés, J.; López-Navarro, E.; Romero, J.; Roselló, M. (2021). Probabilistic analysis of random nonlinear oscillators subject to small perturbations via probability density functions: Theory and computing. European Physical Journal Plus. 136(7):1-23. https://doi.org/10.1140/epjp/s13360-021-01672-wS1231367W.L. Oberkampf, S.M. De Land, B.M. Rutherford, K.V. Diegert, K.F. Alvin, Error and uncertainty in modeling and simulation. Reliab. Eng. Syst. Saf. 75, 333–357 (2002)T. Soong, Random Differential Equations in Science and Engineering, vol. 103 (Academic Press, New York, 1973)Kloeden, P., Platen, E.: Numerical Solution of Stochastic Differential Equations, Ser. Stochastic Modelling and Applied Probability, vol. 23. Springer, Berlin Heidelberg (1992)J.L. Bogdanoff, J.E. Goldberg, M. Bernard, Response of a simple structure to a random earthquake-type disturbance. Bull. Seismol. Soc. Am. 51, 293–310 (1961)L. Su, G. Ahmadi, Earthquake response of linear continuous structures by the method of evolutionary spectra. Eng. Struct. 10, 47–56 (1988)X. Jin, Y. Tian, Y. Wang, Z. Huang, Explicit expression of stationary response probability density for nonlinear stochastic systems. Acta Mech. 232, 2101–2114 (2021)D. Lobo, T. Ritto, D. Castello, E. Cataldo, Dynamics of a Duffing oscillator with the stiffness modeled as a stochastic process. Int. J. Non-Linear Mech. 116, 273–280 (2019)Y. Lin, G. Cai, Probabilistic Structural Dynamics: Advanced Theory and Applications (McGraw-Hill, Cambridge, 1995)C. To, Nonlinear Random Vibration: Analytical Techniques and Applications (Swets & Zeitlinger, New York, 2000)M. Kaminski, The Stochastic Perturbation Method for Computational Mechanics (Wiley, New York, 2013)J.J. Stoker, Nonlinear Vibrations (Wiley (Interscience), New York, 1950)N. McLachlan, Laplace Transforms and Their Applications to Differential Equations, vol. 103 (Dover Publ. INc., New York, 2014)R.F. Steidel, An Introduction to Mechanical Vibrations (Wiley, New York, 1989)G. Casella, R. Berger, Statistical Inference (Cengage Learning, New Delhi, 2007)H.V. Storch, F.W. Zwiers, Statistical Analysis in Climate Research (Cambridge University Press, Cambridge, 2001)J.V. Michalowicz, J.M. Nichols, F. Bucholtz, Handbook of Differential Entropy (CRC Press, Boca Raton, 2018)H. Banks, H. Shuhua, W. Clayton Thompson, Modelling and Inverse Problems in the Presence of Uncertainty (Ser. Monographs and Research Notes in Mathematics. CRC Press, Boca Raton, 2001)Garg, V.K., Wang, Y.-C.: 1 - signal types, properties, and processes. In: Chen, W.-K. (ed.) The Electrical Engineering Handboo
Acceptability of the HPV vaccine among Spanish university students in the pre-vaccine era: a cross-sectional study
Introducción. El cáncer de cuello de útero (CCU), segunda causa de mortalidad por cáncer en mujeres, está asociado a la infección por virus de papiloma humano (VPH), cuya máxima prevalencia se sitúa entre los 20 y 24 años de edad. Desde 2006 se dispone de una vacuna contra el VPH. El objetivo de este estudio es evaluar los conocimientos sobre CCU, la infección por VPH y su vacuna, valorando su aceptabilidad en población universitaria. Métodos. Estudio transversal sobre 1.750 estudiantes de la Universidad de Alicante (2008) seleccionados al azar, proporcional por sexo y estudios, mediante un cuestionario ad-hoc validado. Se calcularon porcentajes, intervalos de confianza, tablas de contingencia según sexo, edad y tipo de estudios, calculando odds ratios ajustadas (OR). Resultados. Muestra con 58,6% mujeres y 6,6% de estudiantes biosanitarios. Un 87,3% dispuestos a vacunarse frente al VPH, el 94,3% vacunaría a sus hijas, un 48,0% había oído hablar de la vacuna. El 90,6% tiene bajos conocimiento sobre la infección por VPH y un 82,2% sobre la vacuna. Un 22,4% manifiesta conocer la asociación entre VPH y CCU. Las mujeres registran OR mayores en conocimientos y predisposición a vacunarse. La aceptabilidad de la vacuna contra VPH se asocia con el sexo y la confianza en las vacunas como método preventivo, la influencia de los conocimientos previos es escasa sobre la predisposición vacunal. Conclusiones. Alta aceptabilidad de la vacuna en el periodo estudiado. Aumentar la confianza hacia las vacunas puede influir en una mejor predisposición a vacunarse.Introduction. Cervical cancer (CC), the second most common cause of cancer deaths in women, is associated with the infection of human papillomavirus (HPV) and is more prevalent in women between the ages of 20 and 24. This research is aimed to determine the background about CC, the human papillomavirus infection and its vaccine, assessing its acceptability in university students. Methods. Cross-sectional study over 1,750 students from the University of Alicante (2008) selected at random, proportional associated to gender and studies, by a validated ad-hoc questionnaire. Percentages were computed, confidence intervals, contingency tables according to sex, age and type of studies, calculating adjusted odd ratios (OR). Results. A sample with 58.6 % of women and 6.6% of biohealth students was obtained. 87.3% were willing to have the vaccine to prevent human papillomavirus (HPV), 94.3% would give this vaccine to their daughters, and 48.0% had heard someone talk about the vaccine. 90.6% didn´t have a lot of knowledge about the HPV infection and 82.2% didn´t know much about the vaccine. 22.4% had knowledge of the association between HPV and CC. Women register higher OR in acknowledging the problem and are more receptive to having the vaccine. The HPV vaccine acceptability is associated to the sex, the confidence of vaccines as a preventive method; the influence of the background is low in relation to the vaccine predisposition. Conclusions. A high acceptability of the vaccine was observed in the period of the study. Raising confidence in people about the vaccines can influence for a better predisposition to be vaccinated
El nuevo concepto de auditoria y modificación de las Manifestaciones escritas.
Con la realización de este trabajo se pretende realizar un análisis comparativo sobre cómo se ha visto influenciada la actividad de la auditoría con la llegada de la nueva Normativa Internacional Auditoría aplicadas a España (NIA-ES) en detrimento de las Normas Técnicas Auditoría (NTA), a las que han sustituido. También se pretende dar una breve y concisa introducción acerca del Proyecto de Ley de Auditorías de Cuentas (PLAC), que entrará en vigor probablemente dentro de este mismo año. Analizaré el nuevo concepto de auditoría que ha entrado en vigor con el cambio de Normativa y que queda reflejado en el nuevo proceso de auditoría que se deberá de desarrollar a partir de ahora. Tratando de dar un enfoque más práctico al trabajo compararemos la opinión que les merece dichos cambios a auditores inscritos en el ROAC y a un directivo de una Entidad con obligación de someter a auditoría sus cuentas anuales. Intentando darle un enfoque más particular, examinaremos la Normativa que hace referencia a la Carta de Manifestaciones de la Dirección, evaluando su proceso a realizar durante la auditoría y los cambios en los que se ha visto envuelto recientemente
- …