2,781 research outputs found
Teorías de la fotografía : Continuidades y rupturas en la transición del registro químico al digital
Han pasado más de 25 años desde la aplicación de los primeros procedimientos digitales en fotografía, los que se iniciaron con la digitalización de imágenes analógicas y continuaron con el registro en soportes de almacenamiento digital. Estas transformaciones socavaron fuertemente la estabilidad técnica y la regular evolución tecnológica que durante 150 años sostuvieron las prácticas fotográficas y sujetaron la reflexión sobre la fotografía a la fuerte impronta mecánica y físico-química del dispositivo. Distintas discusiones que tuvieron su origen en el marco positivista decimonónico, se reeditaron, profundizaron y renovaron a lo largo del siglo XX, a la luz de las diversas corrientes del pensamiento humanista y social. El actual momento de transición (irreversible) hacia la materialidad digital supone no sólo una necesaria revisión de aquellos aportes, sino también la una intervención tendiente a revitalizar y repolitizar la discusión teórica. El presente trabajo intenta reponer algunos elementos para tal fin, atendiendo a las principales metamorfosis del dispositivo y a las características emanadas de los propios productos: las fotografías y las imágenes fotográfica
Análisis del Nivel de Desarrollo de las Microempresas Madereras en el Bosque Modelo de Yoro (Honduras). Apoyo a microempresas madereras (ebanistas) de Yoro.
Trabajo fin de Carrera en Cooperación al desarrollo de la UPM, en el que se analiza la situación de la pequeña industria de carpintería dentro del área Bosque Modelo de Yoro, con la finalidad de unificar y reducir así el impacto medioambiental que supone la compra de madera ilegal por parte de estos trabajadores
Efectos del calzado minimalista sobre la musculatura del pie
[Resumen] Introducción: La musculatura del pie es la encargada de controlar el movimiento y la
estabilidad corporal. Su debilidad está relacionada con una variedad de lesiones
musculoesqueléticas y el calzado se ha considerado un factor de riesgo en la debilidad de
dichos músculos. Por lo tanto, se ha analizado el calzado minimalista con el propósito de
comprobar si este es eficaz para el fortalecimiento de la musculatura del pie.
Objetivo: El objetivo de esta revisión es valorar si el calzado minimalista ocasiona efectos
sobre la musculatura del pie.
Metodología: Se realiza una búsqueda bibliográfica en las bases de datos Pubmed y
Scopus durante los meses de febrero y marzo de 2021.
Resultados: Se obtuvieron 37 artículos de los que se seleccionaron 8 por tratar del tema
de interés de esta revisión.
Conclusiones: Tras finalizar el análisis de los diferentes artículos, se puede afirmar que el
calzado minimalista ocasiona cambios en la musculatura del pie[Resumo] Introdución: A musculatura do pé é a encargada de controlar o movemento e a
estabilidade. A súa debilidade está relacionada cunha variedade de lesións
musculoesqueléticas e o calzado considerouse un factor de risco na debilidade destes
músculos. Por isto, analizouse o calzado minimalista co propósito de comprobar si este é
eficaz para o fortalecemento da musculature do pé.
Obxectivo; O obxectivo desta revisión é valorar se o calzado minimalista ocasiona efectos
sobre a musculatura do pé.
Metodoloxía: Realízase unha búsqueda bibliográfica nas bases de datos Pubmed e
Scopus durante os meses de febreiro e marzo de 2021.
Resultados: Obtivéronse 37 artículos dos que se seleccionaron 8 por tratar do tema de
interés desta revisión.
Conclusións: Tras finalizar o análisis dos diferentes artículos, pódese afirmar que o
calzado minimalista ocasiona cambios na musculatura do pé.[Abstract] Introduction: The foot muscles are in charge of controlling body movement and stability.
His weakness is related to a variety of musculoskeletal injuries and the footwear is
considered a risk factor in weakening of these muscles. Therefore, minimalist footwear was
analyzed in order to see if it is effective in strengthening the muscles of the foot.
Objective: The objective of this review is to assess whether minimalist footwear causes
effects on the foot muscles.
Methodology: A bibliographic search was carried out in the Pubmed and Scopus during the
months of February and March 2021.
Results: There were obtained 37 articles of the which there were selected 8 to contain
things of interest for this review.
Conclusions: After finishing the analysis of the different articles, it can be affirmed that the
minimalist footwear causes changes in the musculature of foot.Traballo fin de grao (UDC.FEP). Podoloxía. Curso 2020/202
Teorías de la fotografía: continuidades y rupturas en la transición del registro químico digital
Han pasado más de 25 años desde la aplicación de los primeros procedimientos digitales en fotografía, los que se iniciaron con la digitalización de imágenes analógicas y continuaron con el registro en soportes de almacenamiento digital. Estas transformaciones socavaron fuertemente la estabilidad técnica y la regular evolución tecnológica que durante 150 años sostuvieron las prácticas fotográficas y sujetaron la reflexión sobre la fotografía a la fuerte impronta mecánica y físico-química del dispositivo. Distintas discusiones que tuvieron su origen en el marco positivista decimonónico, se reeditaron, profundizaron y renovaron a lo largo del siglo XX, a la luz de las diversas corrientes del pensamiento humanista y social. El actual momento de transición (irreversible) hacia la materialidad digital supone no sólo una necesaria revisión de aquellos aportes, sino también la una intervención tendiente a revitalizar y repolitizar la discusión teórica. El presente trabajo intenta reponer algunos elementos para tal fin, atendiendo a las principales metamorfosis del dispositivo y a las características emanadas de los propios productos: las fotografías y las imágenes fotográficas.Facultad de Humanidades y Ciencias de la Educació
Use of CO2 for electrosynthesis
Altres ajuts: acords transformatius de la UABA review of the main ideas related to the capture and valorization of CO by using electrochemical processes is presented. The advantages of using an electrode-controlled potential that provides the possibility of reducing CO to non-fossil carbon-based fuels, or of using this atmospheric pollutant in organic synthesis processes that rely on electrocarboxylation steps are outlined. The implications of a reduction in atmospheric CO emissions in the global climate change emergency, while at the same time finding alternative and clean ways of producing valuable fuels and chemicals, are emphasized. Particular attention is paid to the powerful role that ionic liquids can play as ideal solvents and electrolytes in such electrochemical reactions. A general description of the advantages that these liquids have for the solubilization and the support of the electrochemical reduction of CO is presented
-covering red and blue points in the plane
We say that a finite set of red and blue points in the plane in general
position can be -covered if the set can be partitioned into subsets of
size , with points of one color and point of the other color, in
such a way that, if at each subset the fourth point is connected by
straight-line segments to the same-colored points, then the resulting set of
all segments has no crossings. We consider the following problem: Given a set
of red points and a set of blue points in the plane in general
position, how many points of can be -covered? and we prove
the following results:
(1) If and , for some non-negative integers and ,
then there are point sets , like -equitable sets (i.e.,
or ) and linearly separable sets, that can be -covered.
(2) If , and the points in are in convex position,
then at least points can be -covered, and this bound is tight.
(3) There are arbitrarily large point sets in general position,
with , such that at most points can be -covered.
(4) If , then at least points of
can be -covered. For , there are too many red points and at
least of them will remain uncovered in any -covering.
Furthermore, in all the cases we provide efficient algorithms to compute the
corresponding coverings.Comment: 29 pages, 10 figures, 1 tabl
Optimization of nitrogen feeding strategies for improving polyhydroxybutyrate production from biogas by Methylocystis parvus OBBP in a stirred tank reactor
Producción CientíficaThe design of efficient cultivation strategies to produce bioplastics from biogas is crucial for the implementation of this biorefinery process. In this work, biogas-based polyhydroxybutyrate (PHB) production and CH4 biodegradation performance was investigated for the first time in a stirred tank bioreactor inoculated with Methylocystis parvus OBBP. Decreasing nitrogen loading rates in continuous mode and alternating feast:famine regimes of 24 h-cycles, and alternating feast:famine regimes of 24 h:24 h and 24 h:48 h were tested. Continuous N feeding did not support an effective PHB production despite the occurrence of nitrogen limiting conditions. Feast-famine cycles of 24 h:24 h (with 50% stoichiometric nitrogen supply) supported the maximum PHB production (20 g-PHB m−3 d−1) without compromising the CH4-elimination capacity (25 g m−3 h−1) of the system. Feast:famine ratios ≤1:2 entailed the deterioration of process performance at stoichiometric nitrogen inputs ≤60%.Ministerio de Ciencia, Innovación y Universidades (grant BES-2016-077160)Ministerio de Ciencia, Innovación y Universidades (project CTM2015-70442-R)Junta de Castilla y León (projects UIC 071 and CLU 2017–09
the role of adenosine monophosphate
Funding Information: The authors acknowledge financial support from the European Innovation Council (Horizon 2020 Project: 965018—BIOCELLPHE), the MCIN/AEI/10.13039/501100011033 (grant PID2019-108954RB-I00), the FSE (“El FSE invierte en tu futuro”), the Xunta de Galicia/FEDER (grant GRC ED431C 2020/09), the European Regional Development Fund (ERDF), and the Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior, FCT-MCTES (grants UIDB/50006/2020, UIDP/50006/2020 and Met4cat, EXPL/QUI-COL/0263/2021). J. F.-L. thanks FCT-UNL for the research contract through the Program DL 57/2016−Norma Transitória. S. N. thanks the FCT-MCTES Portugal for her doctoral grant associated with the Chemistry PhD program (SFRH/BD/144618/2019). C. F.-L. acknowledges Xunta de Galicia for a predoctoral scholarship (Programa de axudas á etapa predoutoral). C. L., A. F. L., S. N and J. F. L thank the financial support of the PROTEOMASS Scientific Society (Portugal) (General Funding Grants 2022-2023) and the Associate Laboratory Research Unit for Green Chemistry-Clean Processes and Technologies - LAQV/REQUIMTE. This work was carried out in part through the use of the INL Advanced Electron Microscopy, Imaging and Spectroscopy Facility and Microscopy Facility at CACTI (Universidade de Vigo). The authors thank Dr. Jamila Djafari for her assistance with the graphical abstract. Publisher Copyright: © 2023 The Royal Society of Chemistry.The seed-mediated growth of gold nanostructures is known to be strongly dependent not only on the gold seed nanocrystal structure but also on the presence of different additives that may influence the morphology, and therefore the crystalline structure of the final nanoparticle. Among the different additives or capping ligands, biomolecules are an interesting family due to their potential biomedical applications such as drug delivery, bioimaging, biosensing, phototherapy, and antimicrobial activities. Here, we develop a seed-mediated strategy for synthesizing uniform Au nanostars with tuneable optical properties which involves adenosine monophosphate (AMP) as a capping ligand. The experimental data reveal the key role of AMP not just providing colloidal stability and directing the reduction of the gold precursor via complexation but also mediating the anisotropic growth of the Au seeds via its selective adsorption on the different crystalline facets of Au nanoparticles. These observations agree with theoretical simulations carried out using molecular dynamics and density functional theory (DFT) calculations. Interestingly, the obtained Au nanostars showed high thermal stability as well as colloidal stability in polar organic solvents, which allowed their direct silica coating via the Stöber method. Importantly, we also explored the mimic enzymatic activity of the resulting gold nanostars and observed a superior catalytic activity compared with other gold nanoparticles reported in the literature.publishersversionpublishe
A study of the artistic corpus of red cave paintings in El Buxu cave (Cangas de Onís, Asturias, Spain)
El Buxu cave, which is located in the village of Cardes (Cangas de Onís, Asturias), has been studied since the
1980s, with multiple excavations taking place inside the cave. This work has uncovered a complete artistic
corpus, marking out several phases of occupation, with paintings dating to the first phases of the Upper
Palaeolithic, Solutrean and Lower and Middle Magdalenian periods.
This paper presents a new review of its rock art, documenting all of the red paintings inside the cave, most of
which have never been published up until this point. The most notable inclusion is the new description of a
zoomorphic figure painted in red, which has previously been interpreted as an aurochs, but whose features are in
fact closer to those of a deer or reindeer.
In addition, stratigraphic analysis of some of the paintings has revealed that they are overlapped by Solutrean
and Magdalenian engravings and black paintings inside the cave. Elemental analysis was performed on series of
red pigments and ochre samples, recovered from various strata using X-ray fluorescence spectroscopy. The
resulting dataset was treated using Principal Component Analysis, providing a deeper understanding of the
composition of the rock art in El Buxu cave, while uncovering potential correlations between the samples ac-
cording to their elemental composition.
After comparing additional evidences from other red cave paintings in the region with the red pictographs in
the cave, along with the stratification of paint pigments and their relationship with the ochre samples in each
stratum, it appears that the red paintings comprise the oldest group of pictures inside the cave and can be broadly
dated to the pre-Magdalenian cultural period.Our special aknowledgment to the National University of Distance Education (UNED), for its funding for open-access publishin
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