244 research outputs found
Epidemiología de las fracturas de perfil osteoporótico
Las fracturas osteoporóticas de cadera van acompañadas de una morbimortalidad altas. Entre los factores de riesgo de padecer una fractura de este tipo se encuentra el haber sufrido otra fractura de este tipo con anterioridad.
Objetivo: conocer las características epidemiológicas de los pacientes con fractura de perfil osteoporótico en el área sanitaria dependiente del Hospital "Virgen de la Victoria" de Málaga.
Pacientes y métodos: se incluyen a las mujeres que han sufrido una fractura de tipo osteoporótico en cualquier localización anatómica.
Estudio de tipo indagatorio estadístico. Se utiliza a base de datos del programa GIOS (MSD®), en la que se recogen características antropomórficas de las pacientes, así como los hábitos, factores de riesgo y toma de medicación previa
La geología de los planetas: Análisis estadístico de datos composicionales al servicio de la planetología.
Anàlisi estadístic de dades composicionals dels planete
Examining indices of individual-level resource specialization
The variety of resources that a population exploits is known as the “niche width”. A particular
population has a narrow niche if only few kinds of the available resources are exploited by its members.
When the individuals of a population exploit many different resources, then the population has a
wide niche. From this point of view it seems that the niche is a property of the population as a
whole. However, it is well known that many apparently generalist populations are in fact composed
of individual specialists, that is, members that use only small subsets of the population’s niche. This
approach justifies the definition of indices to measure the individual-level resource specialization.
Although this kind of analysis could be applied to any niche variation: oviposition sites, habitat, etc.,
we focus the discussion in terms of analysis of diet data. So as to measure species niche breadth a
comparison between the frequency distribution of the species’ resource use with that of all available
resources is carried out. When a measure of individual specialization is considered, then one should
compare the population’s total diet with the individual use. In particular, the total niche width of a
population should be compared with its two components: within and between-individual variation. In
this sense, in the literature several indices of intrapopulation niche variation are proposed. Our goal is
to describe, compare and evaluate four of the most relevant indices applied in ecology. In this work we
point out how these techniques could be developed in a compositional framework, particularly when
these indices are applied to discrete diet data [e.g. frequency of different prey specimen in the diet]
Could CODA methodology be useful in control chart techniques?
On standard control charts, the hypothesis of normality is usually assumed without any additional
veri cation. Nevertheless, in some cases this assumption is not accurate and might cause errors in
process quality monitoring. In particular, for the control of the proportion of nonconforming units
(p-chart) the normality is doubtful when p is small and consequently, lower control limit less than or
equal to zero are frequent. Some authors have proposed new techniques to de ne limits in the p-chart.
Others have proposed transformations to improve the detection of special causes
Analysis of fossil planktonic foraminifera: the sieve mesh effect
The choice of the sediment size fraction in the analysis of fossil planktonic foraminifera is of
great importance in determining the composition of assemblages. In past studies several size
fractions have been utilised. Imbrie and Kipp (1971) stated that “smaller fractions give rise to too
many uncertainties in the identification of small specimens and require too long to process. Large
mesh size yield undesiderable loss of small species, and small specimens of larger species”. The
adoption of coarser sieve meshes has the effect to reduce the percentages of small sized (usually
living in cold waters) species (Bé and Hutson, 1977). In a comparison between >63 μm and >150
μm size-fraction of planktonic foraminifera assemblages from NW Atlantic Ocean, Smart (2002),
stated that because particular smaller species are either under-represented or even absent from the
larger (>150 μm) size-fraction, the smaller (>63 μm) size-fraction must be included in studies of
planktonic foraminifera. Di Donato et al. (2008) highlighted in the >150 μm size fraction of a core
from the Tyrrhenian Sea, a great loss of the small-sized species Turborotalita quinqueloba in glacial
samples, where this species is very abundant. This caused an increase in warm water species such as
Globigerinoides ruber, apparently reaching typical Holocene values in some full glacial levels.
From the above mentioned statements, it is clear that treatment changes can strongly influence the
results of palaeoclimatic reconstructions based on planktonic foraminiferal assemblages.
As stated by Aitchison (1986, 1992) scale invariance and subcompositional coherence are
fundamental properties of the compositional data analysis (CODA). The main goal of this paper is
to verify if the variable relationships pointing out from CODA of foraminiferal assemblages are or
not influenced by the size fraction and, more in general, to test the robustness of CODA respect to
treatment changes related to different preparation techniques for the analysis of planktonic
foraminifera
Self-consistent modelling of Mercury’s surface composition and exosphere by solar wind sputtering
A Monte-Carlo model of exospheres was extended by treating the solar wind ion induced sputtering
process, quantitatively in a self-consistent way starting with the actual release of particles from the
mineral surface of Mercury. Mercury is a body without a significant atmosphere, thus, the surface is
effected by different processes that are mainly related to the radiation and plasma environment of
the Sun and to micrometeorites, which are delivered to Mercury’s surface. In such a case it can be
assumed that the composition of Mercury’s thin collisionless atmosphere, the exosphere, is related
to the composition of the planetary crustal materials. If so, then inferences regarding the bulk
chemistry of the planet can be made from a study of atoms and molecules in the exosphere after
they are released from the mineral surface by a variety of release processes. One difficult challenge
is the identification of the main source of some elements like H, He, Na or K. Generally it is
believed that H and He come primarily from the solar wind, while Na and K originate from
volatilized materials partitioned between Mercury’s crust and impacts from meteorites. Besides the
before mentioned elements corresponding to spectroscopic observations and experiments with soil
analogues, other elements such as O, Na, Mg, Al, Si, P, S, K, Ca, Ti, Cr, Fe, Ni, Zn, OH should also
be related with Mercury’s surface soils (Wurz et al., 2010, and references therein). Based on
available observational data and literature data we established a global model for the surface
mineralogy of Mercury and from that derived the average elemental composition of the surface.
Compositional data analysis has been employed for Mercury’s surface minerals recently by
(Sprague et al., 2009). In these cases the applied method was based on simple correlation methods,
which do not exploit the full potential of the available data. In addition, the closed nature of
compositional data, i.e., the assumption that component concentrations have to sum up to 100% in
an analysis, bears important implications for the statistical analysis of compositional data, which do
not seem to have been sufficiently appreciated until now. To investigate the default of the classical
additive analysis method our research group applied recently a more realistic multiplicative method
(Aitchison, 1986) based on the Euclidean space geometry of the simplex (see the chapter Elements
of simplicial linear algebra and geometry). Our recent results presented in detail in Wurz et al.,
(2010) for Mercury will be discussed. This model serves as a tool to estimate densities of species in
the exosphere depending on the release mechanism and the associated physical parameters
quantitatively describing the particle release from the surface
Impact of a COVID-19 Outbreak in an Elderly Care Home after Primary Vaccination
[EN] Elderly care home residents are particularly vulnerable to COVID-19 due to immunesenescence, pre-existing medical conditions, and the risk of transmission from staff and visitors.
This study aimed to describe the outcomes of a COVID-19 outbreak in a long-term care facility
for elderly persons following the initial vaccination. A single-center, retrospective, observational
design was used to analyze the variables associated with hospitalization and death rate by logistic
regression. Adjusted odds ratios (aOR) and their 95% confidence intervals (CI) were calculated.
Sixty-eight residents received the first dose of the COVID-19 vaccine. Despite being negative six days
after vaccination, the performance of a second test 4 days later revealed 51 positives (75.0%) among
residents and 18 among workers (56.3%). A total of 65 of the 68 residents (95.58%) had positive
results with symptoms, whereas 34.9% required hospitalization, and 25.8% died. The best-fitting
model to explain the distribution of cases reflects three points at the time of infection.. The time
from vaccination to symptom onset explains the hospitalization and mortality rates since a day
elapsed halves the risk of hospitalization (aOR = 0.57; CI = 0.38−0.75) and the risk of death by a
quarter (aOR = 0.74; CI = 0.63−0.88). Nursing homes present an elevated risk of transmission and
severity of SARS-CoV-2 infection. Although vaccination reduces the risk of hospitalization and
death, extreme prevention and control measures are essential in these institutions despite the high
vaccination coverage.S
Influencia del patrón en la adaptación del almendro frente al estrés hídrico
Comunicación presentada al XXXVII Congreso Nacional de Riegos, celebrado en Don Benito del 4 al 6 de Junio de 2019 y organizada por la Asociación Española de Riegos y Drenajes y la Universidad de ExtremaduraEn las últimas décadas el cultivo del almendro ha experimentado una gran transformación, pasando de ser un cultivo marginal a constituir un cultivo principal y ocupando en la actualidad amplias zonas de regadío. Sin embargo, la implantación de un sistema de riego no siempre es posible y numerosas plantaciones de almendro continúan realizándose en secano. En estas condiciones la elección del material vegetal adecuado es un factor importante y existe una presión considerable en el sector agrícola para producir de modo más eficiente, reduciendo la cantidad de agua aplicada. Se pretende conocer la respuesta fisiológica al déficit hídrico de plantas de almendro (Prunus dulcis L. cv. Soleta) autorradicadas o injertadas en Rootpac20, mediante el estudio de las relaciones hídricas, crecimiento, transpiración e intercambio gaseoso. La respuesta fisiológica fue evaluada durante un ciclo de estrés hídrico (supresión del riego durante 20 días) y un posterior ciclo de recuperación en plantas en maceta creciendo en invernadero. Los resultados mostraron diferentes respuestas de la variedad Soleta dependiendo de la presencia o no de patrón. El desarrollo de las plantas se vio afectado por el régimen hídrico y la biomasa foliar se redujo en las plantas en las que el riego fue suprimido. El estrés hídrico redujo el diámetro del tronco en los dos formatos, pero el patrón Rootpac20 marcó de una manera más acusada este comportamiento. La evapotranspiracion se redujo según descendió la humedad del sustrato. Cuando el riego se restableció en las plantas del tratamiento deficitario, los valores de evapotranspiración aumentaron, pero permanecieron más bajos que las plantas regadas durante todo el ensayo. El pie franco minimizó la reducción de la fotosíntesis durante la fase de estrés y facilitó la recuperación cuando el riego se restableció, consiguiendo mejor estado hídrico y una rehidratación más rápida que las plantas injertadas sobre patrón Rootpac20.Fondo Europeo Agrícola de Desarrollo Rural (FEADER
Diseño de una fachada termoeléctrica activa
La conciencia social sobre el uso eficiente de la energía ha aumentado considerablemente en estos
últimos años. La envolvente y los sistemas de climatización son los principales responsables de la
demanda y el consumo de energía en los edificios.
Teniendo estos puntos en cuenta, un grupo de investigación de la Escuela de Arquitectura de la
Universidad de Navarra está desarrollando un proyecto llamado “Desarrollo, construcción y análisis
de un cerramiento de fachada activo con células Peltier”. Dicho trabajo se centra en la obtención de
una solución integral de cerramiento y climatización. Para ello se plantea un cerramiento de fachada
ventilada opaco industrializado de altas prestaciones capaz de adaptarse de forma dinámica a los
cambios ambientales que incluye un sistema de climatización por termoelectricidad en su interior.
El sistema de fachada innovador planteado incorpora el sistema de climatización mediante células
Peltier que consiste en un sistema de bomba de calor termoeléctrica diseñado para ser incorporado en
la fachada de los edificios. Además, se han introducido una serie de mecanismos que permiten el
control del flujo de aire dentro de la cámara del cerramiento.
Con la intención de cuantificar y comprobar el comportamiento real de las ideas antes planteadas, en
la Escuela de Arquitectura de la Universidad de Navarra, se ha construido un prototipo del sistema de
fachada innovador y se ha instalado en un módulo prefabricado de ensayo que simula una habitación
tipo. De esta manera se están recogiendo datos reales de comportamiento, que permitirán realizar una
valoración objetiva del nuevo sistema
Source apportionment of atmospheric trace gases and particulate matter: comparison of log-ratio and traditional approaches
In this paper we compare multivariate methods using both traditional approaches, which
ignore issues of closure and provide relatively simple methods to deal with censored or
missing data, and log-ratio methods to determine the sources of trace constituents in the
atmosphere. The data set examined was collected from April to July 2008 at a sampling site
near Woods Hole, Massachusetts, along the northeastern United States Atlantic coastline.
The data set consists of trace gas mixing ratios (O3, SO2, NOx, elemental mercury [Hgo], and
reactive gaseous mercury [RGM]), and concentrations of trace elements in fine (<2.5 μm)
particulate matter (Al, As, Ba, Ca, Cd, Ce, Co, Cs, Fe, Ga, Hg, K, La, Mg, Mn, Na, P, Pb,
Rb, Sb, Sr, Th, Ti, V, Y, and Zn) with varying percentages of censored values for each
species.
The data were separated into two subcompositions: s1, which is comprised by RGM and
particulate Hg (HgP), which are both highly censored; and s2 which includes all of the trace
elements associated with particulate matter except Hg, and the trace gases O3, SO2, NOx, and
Hgo. Principal factor analysis (PFA) was successful in determining the primary sources for
constituents in s2 using both traditional and log-ratio approaches. Using the traditional
approach, regression between factor scores and RGM and particulate Hg concentrations
suggested that none of the sources identified during PFA led to positive contributions of
either reactive mercury compound. This finding is counter to most conventional thinking and
is likely specious, resulting from removal of censored data (up to >80% of the entire dataset)
during the analysis.
Log-ratio approaches to find relationships between constituents comprising s2 with RGM
and HgP (i.e., s1) focused on log-ratio correlation and regression analyses of alr-transformed
data, using Al as the divisor. Regression models accounted for large fractions of the variance
in concentrations of the two reactive mercury species and generally agreed with
conceptualizations about the formation and behavior of these species. An analysis of
independence between the subcompositions demonstrated that the behavior of the two
constituents comprising s1 (i.e., RGM and HgP) is dependent on changes in s2. Our findings
suggest that although problems related to closure are largely unknown or ignored in the
atmospheric sciences, much insight can be gleaned from the application of log-ratio methods
to atmospheric chemistry data
- …