Auslander-Buchweitz approximation theory for triangulated categories

We introduce and develop an analogous of the Auslander-Buchweitz approximation theory (see \cite{AB}) in the context of triangulated categories, by using a version of relative homology in this setting. We also prove several results concerning relative homological algebra in a triangulated category \T, which are based on the behavior of certain subcategories under finiteness of resolutions and vanishing of Hom-spaces. For example: we establish the existence of preenvelopes (and precovers) in certain triangulated subcategories of \T. The results resemble various constructions and results of Auslander and Buchweitz, and are concentrated in exploring the structure of a triangulated category \T equipped with a pair (\X,\omega), where \X is closed under extensions and $\omega$ is a weak-cogenerator in \X, usually under additional conditions. This reduces, among other things, to the existence of distinguished triangles enjoying special properties, and the behavior of (suitably defined) (co)resolutions, projective or injective dimension of objects of \T and the formation of orthogonal subcategories. Finally, some relationships with the Rouquier's dimension in triangulated categories is discussed.Comment: To appear at: Appl. Categor. Struct. (2011); 22 page

Possible Role of Nrf2 in Oxidative and Inflammatory Processes During Menopause

The increase in life expectancy leads to the possibility of development chronic diseases, from special physiological conditions as occurs in the menopause, which is defined as the permanent cessation of ovulation, marked by the end of menstruation. It has been related to decreased ovarian function that occurs around an age of 45 years. This event involves the reduction in estrogen production and may contribute to the development of chronic-degenerative diseases. Many diseases developed during menopause have been associated with oxidative stress, such as osteoporosis, hot flushes, cognitive impairment, insulin resistance, dry skin, obesity, and cardiovascular events. The knowledge about the participation of Nrf2 in diseases that occur during menopause is very limited. Here, only diseases such as osteoporosis, cardiovascular diseases and dry skin, which are present during menopause and its later stages have been described. The Nrf2 pathway involves the participation of PI3K/Akt, MAPK, and eNOS, which act as mediators for cytoprotection and antioxidation. Compounds such as equol, fitoestrogens, alkyl cathecols, or curcumin could be offered as options to antioxidant treatment, added the fact that they are present in fruits and vegetables which are rich in vitamins, minerals and calcium, thus including all the required nutrients for an adequate nutrition

Análisis estadístico implicativo de los conocimientos previos sobre propiedades de operaciones con números reales de ingresantes a carreras de ingeniería de FACENA

Este trabajo tiene por objetivo presentar un método de Estadística multivariada llamado Análisis Estadístico Implicativo (ASI) que permite determinar los conocimientos de los estudiantes (materializados en sus respuestas a distintos ítems de evaluación) así como las relaciones conceptuales que entre ellos establecen los sujetos evaluados. ASI, a diferencia de los métodos clásicos de asociación de variables, permite detectar relaciones del tipo “si p, entonces, casi siempre q”, a las cuales se las denomina cuasi-implicaciones o reglas. Estas relaciones se presentan mediante un “grafo implicativo” que permite la mejor interpretación de las relaciones mencionadas. Para lograr el objetivo propuesto en este artículo, se utilizó ASI para analizar un ítem de evaluación de una prueba de diagnóstico suministrada a ingresantes a Ingeniería Eléctrica, Ingeniería en Agrimensura e Ingeniería en Electrónica al inicio del año lectivo 2017 y se realizó una comparación entre las relaciones detectadas según los alumnos pertenezcan a una u otra carrera. A modo general, se observaron saberes y relaciones conceptuales establecidos por los alumnos que dan cuenta de su escasa evolución del pensamiento aritmético al algebraico, independientemente de la carrera a la que pertenecen

Low-cost ceramic membranes manufacture using INKJET technology for active layer deposition and validation on membrane bioreactors

[EN] The fabrication of eco-friendly ceramic membranes based on low-cost raw materials, using digital INKJET printing techniques for active layer deposition and its validation in a membrane bioreactor (MBR) has been studied. The raw materials used in the manufacture of the support layer were UA50/2 clay, chamotte, calcium carbonate and potato starch. A MBR laboratory plant was operated to treat municipal wastewater with three ceramic membranes with different grammages in the selective layer deposition. The membrane performance at laboratory scale was evaluated in terms of transmembrane pressure (TMP) evolution for a constant permeate flux, permeate quality and mixed liquor characteristics. From these experiments, it was selected the membrane which obtained the lowest TMP profile maintaining appropriate water quality parameters (chemical oxygen demand (COD) removal percentage around 90% and turbidity around 0.06 NTU). This membrane was also operated at pilot plant scale in order to validate it at higher scale. Results indicated that TMP values were in the range of 0.06 and 0.1 bar, COD removal percentage was around 98% and microbiology analysis demonstrated that the quality of the effluent, according to European regulation 2020/741, can be classified as Class A and it can be reused for non-potable purposes.Authors thank the FEDER/Ministerio de Ciencia, Innovacion y Universidades-Agencia Estatal de Investigacion for the financial support (Reference of the project: RTC-2017-5897-5-AR).Lujan Facundo, MJ.; Mendoza Roca, JA.; Bes-Piá, M.; Zuriaga-Agusti, E.; Mestre, S.; Palacios, M. (2023). Low-cost ceramic membranes manufacture using INKJET technology for active layer deposition and validation on membrane bioreactors. Process Safety and Environmental Protection. 176:618-626. https://doi.org/10.1016/j.psep.2023.06.04561862617

Mechanical alloying of Hf and Fe powders

Pure crystalline Hf and Fe powders were mixed and milled under an argon atmosphere. The evolution of the system with milling time was followed with Mossbauer effect spectroscopy and X-ray diffraction. The results indicate that in the first stages an amorphous Fe-rich alloy was gradually formed together with a solid solution of Hf in Fe beyond the solubility limit.Facultad de Ciencias Exacta

Feedback Control Methods on Short-Period Orbits Of the Earth-Moon Equilateral Libration Points

Recent research by the authors suggests a unique approach to perform Lunar occultations for a diverse set of scientific applications. Under the circular restricted three-body problem assumptions, short-period orbits (SPOs) near the Earth-Moon equilateral Libration points have been suggested for optimal eclipse time and minimal fuel consumption requirements to stay in orbit. Nevertheless, under the presence of orbital perturbations, SPOs are no longer stable as gravitational effects from neighboring celestial bodies continuously perturb these orbits. In this sense, the current study compares a wide range of control methods, including Lyapunov-based adaptive control schemes and fuel-optimal control policies, to address the fuel consumption and tracking issues of the perturbed system. This inquiry attests that perturbations are effectively cancelled out to achieve the proposed scientific objectives with minimal station-keeping requirements

Intensive Habitat Loss in South Spain: Arborescent Scrubs with <em>Ziziphus</em> (5220*)

The habitat arborescent matorral with Ziziphus (5220*) was included in the Habitats Directive of the European Commission. These plant formations represent the maximum potential vegetation in a very restrictive arid environment, since it encompasses endemic, tropical, or Maghrebian floristic elements, and from other areas of the ancient Thetis Sea. In fact, the version of this community with Gymnosporia senegalensis (Lam.) Loes. [=Maytenus senegalensis (Lam.) Exell] constitutes extraordinarily singular flora formations in the Iberian southeast. These are unique communities in Europe and ecologically extremely valuable and, however, have been included among the Europe’s most endangered habitats. The vast economic development experienced in South Spain based on the remarkable transformation of traditional farming patterns into a highly profitable agriculture that uses industrial production methods and the groundwater intensively (agriculture intensification and land-use change), in addition to urbanization without sustainable land planning, determines that European G. senegalensis populations are seriously threatened by severe habitat destruction and fragmentation

Conocimientos previos sobre propiedades de operaciones con números reales de ingresantes a la universidad. Su análisis usando análisis estadístico implicativo

This work’s objective is to determine how knowledgeable new university students are regarding the properties of operations with real numbers (addition, multiplication, exponentiation and nth root) and what relations they establish between the knowledge that they have acquired in their pre-university education. In order to accomplish the planned objectives, in this work, via use of Statistical Implicative Analysis (SIA), the answers provided to a questionnaire found in a test of previous real numbers knowledge that was taken by new students of Facultad de Ciencias Exactas–UNNE (at the beginning of the academic year of 2017)were analyzed. SIA is a multivariate analysis technique that allows relations of type “if p, then, almost q” (quasi-implications or rules) between variables (the answers provided to the previously-mentioned question) to be established. These relations allow for exploration of the conceptual relations established by the analyzed subject and detect the cognitive difficulties that said concepts offer. The results are represented and visualized by use of an “implicative graph” and later bysimilarity and cohesitive trees that make possible the establishment of R-rules (quasi-implications that relate variables and rules or rules between each other). By observing the knowledge and conceptual relations established by the students, their lacking evolution from arithmetic thinking to algebraic is brought to light.Este trabajo tiene por objetivo determinar los conocimientos de los ingresantes universitarios respecto a las propiedades de operaciones con números reales (suma, multiplicación, potenciación y radicación) y qué relaciones establecen entre los saberes que al respecto han construido en su formación preuniversitaria. Para cumplir los objetivos propuestos, se analizaron, utilizando Análisis Estadístico Implicativo (ASI), las respuestas al tercer ítem de la prueba de diagnóstico de conocimientos previos de números reales, suministrada a ingresantes a la Facultad de Ciencias Exactas de la UNNE, al inicio del ciclo lectivo 2017. ASI es una técnica de análisis multivariado que permite establecer relaciones del tipo “si p, entonces, casi siempre q” (cuasi-implicaciones o reglas) entre variables (las respuestas al ítem de evaluación citado). Estas relaciones permiten explorar las relaciones conceptuales establecidas por el sujeto evaluado y detectar las dificultades cognitivas que dichos conceptos les ofrecen. Los resultados se presentan y visualizan mediante un “grafo implicativo” y posteriormente se construyen árboles de similaridad y árboles cohesitivos que permiten establecer R-reglas (cuasi implicaciones que relacionan variables con reglas o reglas entre sí). Se observaron saberes y relaciones conceptuales establecidas por los alumnos que dan cuenta de su escasa evolución desde el pensamiento aritmético al algebraico. &nbsp

Spatial and temporal variability of discards indicators and fishery factors affecting otter-trawl fishery in the spanish Mediterranean sea

A set of diversity indices were studied from data of observers on board two Mediterranean trawlers from 2001 to 2009. These diversity indices comprise relationships between total catch, landing and discard fractions to explore the accuracy of the estimates and to analyse the series trends using different methods, such as ARIMA. The hypothesis tested was that diversity indicators give a good representation of the changes produced in impacted bottom‐trawl areas, providing a reasonable fit of the data. ARIMA models are useful because they handle time-correlated modelling and forecasting. These techniques can also reveal changes in total catch as well changes in catch composition, probably induced by changes in effort fishery, seasonal (time) fluctuations, and environmental or climatic processes. Contrasted trends were also compared with survey data by MEDITS Mediterranean trawl survey time‐series indicator

Prevalencia de Portadores de Staphylococcus aureus en personal de Salud del Hospital Victor Lazarte Echegaray y Sensibilidad antimicrobiana in vitro

The present study was carried out with the purpose of determining the prevalencia of payees of Staphylococcus aureus in personal of health of the Hospital Victor to Rope you Echegaray, during the month of August of the 2003 and to determine its sensibility to the antimicrobianos in vitro. They took samples of nasal and pharyngeal hisopados to personal of surgery, UCI-UCIN and room of operations those which of they cultivated between tioglicolato, agar bleeds and agar Manitol. The isolated stumps were identified by means of the tests catalasa, coagulasa, coloration gram, action on the manitol and then they were carried out antibiogramas by means of the method of Kirby and Bauer. The results show a prevalencia of 28,6% in personal of health, in personnel medical 38,5%, in technicians 23,1% and in nurses 20,8%. In personal of the service of UCI-UCIN, he/she was 46,7%, in surgery 28,6% and in SOP 15%. The nasal payees were 23,8% and pharyngeal 15,9%. Of the used antimicrobianos 100% of sensibility was presented to vancomicina, 94,44% to amikacina, 77,78% to oxacilina and ciprofloxacina, 72,22% to cefalexina, 55,56% to amoxil/ac. clavulánico and ceclor, 27,78% to clindamicina and 16,67% to penicillin.El presente estudio se realizó con la finalidad de determinar la prevalencia de portadores de Staphylococcus aureus en personal de salud del Hospital Víctor Lazarte Echegaray, durante el mes de agosto del 2003 y determinar su sensibilidad a los antimicrobianos in vitro. Se tomaron muestras de hisopados nasales y faríngeos a personal de cirugía, UCI-UCIN y sala de operaciones las cuales de cultivaron en medio tioglicolato, agar sangre y agar Manitol. Las cepas aisladas se identificaron mediante las pruebas catalasa, coagulasa, coloración gram, acción sobre el manitol y luego se realizaron antibiogramas mediante el método de Kirby y Bauer. Los resultados muestran una prevalencia de 28,6% en personal de salud, en personal médico 38,5%, en técnicos 23,1% y en enfermeras el 20,8%. En personal del servicio de UCI-UCIN, se halló 46,7% , en cirugía 28,6% y en SOP 15%. Los portadores nasales fueron el 23,8% y faríngeos el 15,9%. De los antimicrobianos utilizados se presentó 100% de sensibilidad a vancomicina, 94,44% a amikacina, 77,78% a oxacilina y ciprofloxacina, el 72,22% a cefalexina, el 55,56% a amoxil/ac. clavulánico y ceclor, el 27,78% a clindamicina y el 16,67% a penicilina