5,116 research outputs found
A new formulation of compartmental epidemic modelling for arbitrary distributions of incubation and removal times
The paradigm for compartment models in epidemiology assumes exponentially
distributed incubation and removal times, which is not realistic in actual
populations. Commonly used variations with multiple exponentially distributed
variables are more flexible, yet do not allow for arbitrary distributions. We
present a new formulation, focussing on the SEIR concept that allows to include
general distributions of incubation and removal times. We compare the solution
to two types of agent-based model simulations, a spatially homogeneous one
where infection occurs by proximity, and a model on a scale-free network with
varying clustering properties, where the infection between any two agents
occurs via their link if it exists. We find good agreement in both cases.
Furthermore a family of asymptotic solutions of the equations is found in terms
of a logistic curve, which after a non-universal time shift, fits extremely
well all the microdynamical simulations. The formulation allows for a simple
numerical approach; software in Julia and Python is provided.Comment: 21 pages, 11 figures. v2 matches published version: improved
presentation (including title, abstract and references), results and
conclusions unchange
Football performance indicators review
Se ha realizado una revisión y selección de algunos de los factores que están implicados en el rendimiento deportivo en fútbol haciendo una
recopilación de las variables que han tenido en cuenta otros investigadores y agrupándolas en diferentes bloques. En el primer bloque se presentan los factores físicos y fisiológicos, tanto los genéticos como los susceptibles de ser entrenados. En otro bloque hemos agrupado los factores contextuales en los que incluimos los
psicológicos y sociales, ya que vienen a contextualizar las condiciones del partido y de los jugadores. Por último, desarrollamos los
indicadores técnico tácticos más utilizados para estimar el rendimiento de los equipos de fútbol
Malnutrition as cause and consequence of sensory distorsiones
La malnutrición es una enfermedad provocada por un
exceso o defecto en el consumo o aprovechamiento de los
nutrientes. Habitualmente, se utiliza este término para
referirse a la desnutrición, es decir, a un trastorno derivado
del déficit de algún macro y o micronutrientes.
Las alteraciones quimiosensoriales pueden reducir de
forma importante la alimentación en el individuo, por lo
que es importante verificar que el aporte de nutrientes y, de
forma concreta, de algunos micronutrientes, sea suficiente,
ya que alguno de ellos, como el zinc, desempeñan un papel
primordial en las alteraciones del gusto y del olfato.
Además, el paciente malnutrido o con una alimentación
que excluya gran número de alimentos, tiene mayor
riesgo de presentar déficits de dichos micronutrientes.
Diversas enfermedades, tanto agudas como crónicas, se
asocian a alteraciones de la percepción sensorial, y pueden
llegar a afectar a más del 50% de las personas mayores de
65 años. Los efectos provocados por los fármacos y algunos
tratamientos como la quimioterapia y la radioterapia, juegan
también un papel muy importante en la distorsión sensorial
y en la incidencia de malnutriciónMalnutrition is a pathological condition caused by an
excess or deficiency in the consumption or the use of the
nutrients. Usually this term refers to a lack of adequate
nourishment, a disorder resulting from a deficiency of
some macro and/or micronutrients.
Chemo-sensory alterations can significantly reduce
food choice and intake, so it is very important to verify
that the supply of nutrients and specifically of some
micronutrients are sufficient. Some of them, such as
“zinc”, play a very important role in alterations in the
sense of taste and smell.
In addition malnutrition patients or a poorly-balanced
diet or faulty utilization of foods have increased the risk
of deficiencies in these micronutrients.
Several types of diseases, both acute and chronic ones,
are associated with sensory perception and can affect
more than 50% of people over 65 years old. The effects
caused by drugs and some treatments such as chemotherapy
and radiation therapy play an important role in sensory
distortion and the incidence of malnutritio
A revised distance to IRAS 162932422 from VLBA astrometry of associated water masers
IRAS 16293-2422 is a very well studied young stellar system seen in
projection towards the L1689N cloud in the Ophiuchus complex. However, its
distance is still uncertain with a range of values from 120 pc to 180 pc. Our
goal is to measure the trigonometric parallax of this young star by means of
HO maser emission. We use archival data from 15 epochs of VLBA observations
of the 22.2 GHz water maser line. By modeling the displacement on the sky of
the HO maser spots, we derived a trigonometric parallax of mas,
corresponding to a distance of pc. This new distance is in
good agreement with recent values obtained for other magnetically active young
stars in the L1689 cloud. We relate the kinematics of these masers with the
outflows and the recent ejections powered by source A in the system.Comment: 14 pages, 6 tables, 8 figures. Accepted to be published in Astronomy
\& Astrophysic
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