2,129 research outputs found
Limitations of the Standard Procedure for the Evaluation of Marble and Limestone for Use in Construction: A Critical Analysis and Proposal for Modification
The selection of natural stone for each specific use must be based on determinations which assess their technical quality and ensure their suitability for the environment in which they will be utilized. Among the criteria to be considered, a petrographic characterization is basic to deduce the behaviour of the stone to external
agents. Current European regulations for the valuation and use of a stone present serious constraints in connection with the petrographic characterization and with the definition of some of the technological tests,
which can endanger the suitability of a stone for use in construction. Two commercial limestones and one
marble, are studied following the existing European Standards, to explain reasonably the behavior of these
materials and deduce the most appropriate uses. Finally the results lead to certain recommendations to modify existing regulations
Heavy mesons in the Quark Model
Since the discovery of the , the quark model was very successful in
describing the spectrum and properties of heavy mesons including only
components. However since 2003, with the discovery of the , many
states that can not be accommodated on the naive quark model have been
discovered, and they made unavoidable to include higher Fock components on the
heavy meson states. We will give an overview of the success of the quark model
for heavy mesons and point some of the states that are likely to be more
complicated structures such as meson-meson molecules.Comment: Contribution to the Proceedings of the 15th International Workshop on
Meson Physics - MESON201
The X(3872) and other possible molecular states
We perform a coupled channel calculation of the and sectors
in the framework of a constituent quark model. The interaction for the
states is obtained using the Resonant Group Method (RGM) and the underlying
quark interaction model. The coupling with the two quark system is performed
using the model. The X(3872) is found as a molecular state with a
sizable component. A comparison with Belle and BaBar data has been
done, finding a good agreement. Other possible molecular molecular states are
discussed.Comment: 5 pages, 5 figures, Proceedings to the Hadron 2009 - XIII
International Conference on Hadron Spectroscopy, Florida State University
(USA
Optimal Carbon Taxes for Emissions Targets in the Electricity Sector
The most dangerous effects of anthropogenic climate change can be mitigated
by using emissions taxes or other regulatory interventions to reduce greenhouse
gas (GHG) emissions. This paper takes a regulatory viewpoint and describes the
Weighted Sum Bisection method to determine the lowest emission tax rate that
can reduce the anticipated emissions of the power sector below a prescribed,
regulatorily-defined target. This bi-level method accounts for a variety of
operating conditions via stochastic programming and remains computationally
tractable for realistically large planning test systems, even when binary
commitment decisions and multi-period constraints on conventional generators
are considered.
Case studies on a modified ISO New England test system demonstrate that this
method reliably finds the minimum tax rate that meets emissions targets. In
addition, it investigates the relationship between system investments and the
tax-setting process. Introducing GHG emissions taxes increases the value
proposition for investment in new cleaner generation, transmission, and energy
efficiency; conversely, investing in these technologies reduces the tax rate
required to reach a given emissions target
Information transfer through intraspecific interactions in a lycosid spider
The transfer of information during agonistic and sexual interactions between adults of Lycosa tarentula fascilventrls is studied. Information theory and correspondence analysis are applied to the intra-individual transition matrices. Information is quantitatively similar
regardless of the context and the sex. Similarity arises mainly from the transition
between motionless and approaching-signalling patterns. There are no pattems strongly
predicting the immediate retreat of the sender and there is a marked predictability of
females immediately attacking in their agonistic interactions. Results fit those expected
if risk of intraspecific interactions in such a solitary predator was arnong the selective
pressures leading to the evolution of communication system
Guidelines for specialized nutritional and metabolic support in the critically-ill patient. Update. Consensus SEMICYUC-SENPE: Oncohematological patient
Patients with cancer, irrespective of the stage of their
disease, can require admission to the intensive care unit
as a result of the complications of their underlying
process or the surgical or pharmacological treatment
provided. The cancer itself, as well as the critical status
that can result from the complications of the disease, frequently
lead to a high degree of hypermetabolism and
inadequate energy intake, causing a high incidence of
malnutrition in these patients. Moreover, cancer causes
anomalous use of nutritional substrates and therefore the
route of administration and proportion and intake of
nutrients may differ in these patients from those in noncancer
patients.Los pacientes portadores de cáncer, en cualquier fase
de su evolución, pueden precisar ingreso en UCI como
consecuencia de complicaciones secundarias a su enfermedad
de base o de las terapias quirúrgicas o farmacológicas
a que se ven sometidos para tratar su enfermedad.
La propia enfermedad cancerosa, así como el estado crítico
a que pueden derivar como consecuencia de las complicaciones
sobreañadidas, con frecuencia condicionan
un alto grado de hipermetabolismo y de déficit de ingesta
nutricional, lo que conduce en estos enfermos a una alta
incidencia de desnutrición. Además, la propia enfermedad
cancerosa condiciona una utilización anómala de los
sustratos nutritivos, lo que podría condicionar una vía de
administración y una proporción y aporte de nutrientes
algo diferenciado de los pacientes no tumorales
Ethical conflicts among physicians and nurses during the COVID‐19 pandemic: A qualitative study
Rationale, Aims and Objectives
The healthcare system and professionals working in the sector have experienced a high caseload during the coronavirus disease 2019 (COVID-19) pandemic. This has increased the potential for morally harmful events that violate professionals' moral codes and values. The aim of this study was to understand and explore experiences of new moral challenges emerging among physicians and nurses caring for individuals during the COVID-19 pandemic.
Method
The consolidated criteria for reporting qualitative research (COREQ) checklist was used in this qualitative study based on Gadamer's phenomenology. Participants were selected using a convenience sampling method. Thirteen medicine and nursing graduates were interviewed in depth. The participants all worked on the frontline at the start of the COVID-19 pandemic. Data were gathered in two basic healthcare districts in Spain, encompassing both primary care and hospital care.
Results
Four main themes emerged from the data analysis: (1) Betrayal of moral and ethical values as a key source of suffering; (2) Ethical and moral sense of failure accompanying loss of meaning; (3) Lack of confidence in performance; (4) Self-demand and self-punishment as personal condemnation among healthcare workers.
Conclusions
Health institutions must implement interventions for health professionals to help mitigate the consequences of experiencing complex ethical scenarios during the pandemic. In addition, they should promote training in moral and ethical deliberation and prepare them to make decisions of great ethical significance
Occupational factors associated with health-related quality of life in nursing professionals: a multi-centre study
Background: Nursing professionals are exposed to stressful situations arising from the work context that may affect health-related quality of life (HRQoL). The objective of this study was to analyse the relationship between sociodemographic and work-related variables regarding HRQoL in nursing professionals.
Methods: A multi-centre, cross-sectional descriptive design was used. The participants consisted 1521 nurses working in healthcare centres, in both primary care and hospital care, in the eight provinces of the Andalusian Public Health System (APHS), Spain. Sociodemographic and work-related variables were analysed: Compassion fatigue, compassion satisfaction and burnout were measured using the professional quality of life questionnaire (ProQOL), and HRQoL was measured using the SF-12 health questionnaire.
Results: Compassion fatigue, burnou, and, to a lesser extent, compassion satisfaction significantly influence the physical and mental components of HRQoL. The simple regression analysis showed that burnout and compassion fatigue were significantly associated with the mental component of HRQoL. Gender influenced the mental component of HRQoL. The rest of the sociodemographic and work-related variables were not significantly related to HRQoL.
Conclusion: Work-related stress and repeated contact with situations of suffering influence HRQoL. Health systems must implement programmes to increase the emotional well-being of workers
Threading Through Macrocycles Enhances the Performance of Carbon Nanotubes as Polymer Fillers
In this work we study the reinforcement of polymers by mechanically
interlocked derivatives of single-walled carbon nanotubes (SWNTs). We compare
the mechanical properties of fibers made of polymers and of composites with
pristine single-walled carbon nanotubes (SWNTs), mechanically interlocked
derivatives of SWNTs (MINTs) and the corresponding supramolecular models.
Improvements of both Young's modulus and tensile strength of up to 200 % were
observed for the polystyrene-MINTs samples with an optimized loading of just
0.01 wt.%, while the supramolecular models with identical chemical composition
and loading showed negligible or even detrimental influence. This behavior is
found for three different types of SWNTs and two types of macrocycles.
Molecular dynamics simulations show that the polymer adopts an elongated
conformation parallel to the SWNT when interacting with MINT fillers,
irrespective of the macrocycle chemical nature, whereas a more globular
structure is taken upon facing with either pristine SWNTs or supramolecular
models. The MINT composite architecture thus leads to a more efficient
exploitation of the axial properties of the SWNTs and of the polymer chain at
the interface, in agreement with experimental results. Our findings demonstrate
that the mechanical bond imparts distinctive advantageous properties to SWNT
derivatives as polymer fillers.Comment: 39 pages, 19 figure
Characteristics of strength and speed of execution in young women soccer players
El objetivo de este estudio fue caracterizar y comparar la fuerza máxima y rápida, la potencia anaeróbica, la velocidad de ejecución y de desplazamiento en función de la posición de juego en 59 jóvenes futbolistas distribuidas en dos categorías. La metodología consistió en una valoración de masa corporal, talla y 4 pruebas, fuerza explosiva (CMJ Y SJ), velocidad (30 m), la potencia anaeróbica (Prueba de Wingate) y la fuerza máxima (%1RM). Los resultados mostraron a las pre-juveniles con los mejores registros en la mayoría de variables a excepción de la talla y el VMP sentadilla. En la prueba de potencia máxima las porteras y defensas pre-juveniles obtuvieron el mejor registro (409,11 W±86,73 W) y 1RM (60,58 Kg±13,69 Kg) sin diferencias significativas. Finalmente, se encontró una interacción significativa entre la posición y la categoría de juego en VMP sentadilla, F55= 21,41; p = 0,021, eta cuadrado= 0,093 entre las jugadoras de las dos categorías estudiadasThe objective of this study was to characterize and compare the maximum and fast strenght, anaerobic power, speed of execution and displacement according to the playing position in 59 young players divided into two categories. The methodology consisted of an assessment of body mass, height and 4 tests, explosive force (CMJ and SJ), velocity (30 m), anaerobic power (Wingate test) and maximum force (% 1RM). The results showed the under 15 years old with the best records on most variables except for the size and mean propulsive velocity (MPV) squat. In the maximum power test pre-juvenile goalkeepers and defences line obtained the best record (409.11 W ± 86.73 W) and 1RM (60.58 kg ± 13.69 Kg) without significant differences. Finally, we found a significant interaction between the position and the game category in MPV squat, F55 = 21.41; P = 0.021, eta square = 0.093 among the players of the two categories studie
- …