849 research outputs found
Exit times in non-Markovian drifting continuous-time random walk processes
By appealing to renewal theory we determine the equations that the mean exit
time of a continuous-time random walk with drift satisfies both when the
present coincides with a jump instant or when it does not. Particular attention
is paid to the corrections ensuing from the non-Markovian nature of the
process. We show that when drift and jumps have the same sign the relevant
integral equations can be solved in closed form. The case when holding times
have the classical Erlang distribution is considered in detail.Comment: 9 pages, 3 color plots, two-column revtex 4; new Appendix and
references adde
About the Dirac Equation with a potential
An elementary treatment of the Dirac Equation in the presence of a
three-dimensional spherically symmetric -potential is
presented. We show how to handle the matching conditions in the configuration
space, and discuss the occurrence of supercritical effects.Comment: 8 pages, 1 postscript figure, Latex, Revise
The fundamental group of the clique graph
AbstractGiven a finite connected bipartite graph B=(X,Y) we consider the simplicial complexes of complete subgraphs of the square B2 of B and of its induced subgraphs B2[X] and B2[Y]. We prove that these three complexes have isomorphic fundamental groups. Among other applications, we conclude that the fundamental group of the complex of complete subgraphs of a graph G is isomorphic to that of the clique graph K(G), the line graph L(G) and the total graph T(G)
Three types of shopping precincts. Three different ways to influence the public sphere of neighborhoods
Indexación: Scopus.Considerando que en la teoría urbana el mercado y
los espacios públicos están históricamente vinculados,
este artículo analiza un mercado, una galería
comercial y un centro comercial (mall). El fin es ilustrar
los factores que son determinantes para que en
Santiago de Chile estas tipologías de comercio adquieran
carácter público y puedan contribuir a la esfera
pública de la ciudad, al menos dentro de las limitaciones
que se derivan de su condición privada. Hasta
ahora el debate ha reflexionado extensivamente sobre
estas tres tipologías, sin embargo, existen aún pocos
estudios que miran la vida pública que tiene lugar en estas diferentes tipologías de manera paralela, considerando
que hoy todas ellas están presentes simultáneamente
en la ciudad y se disputan su espacio en
ella. Esta investigación describe características físicoespaciales
y de administración de estos tres casos para
aportar a las políticas públicas y el diseño urbano. Se
estudia el comercio en relación a la accesibilidad a nivel
metropolitano y en cuanto a los diferentes tipos de
comercio, que pretenden atraer un público diverso y
promueven el carácter público de los espacios.According to urban theory, commerce and public
spaces are historically related to each other.
Based on this premise, this paper analyzes a
market, a shopping center and a mall. The goal
of this research is to identify the key factors that
turn these shopping precincts into public spaces
and contribute to the public sphere in Santiago,
Chile, at least within the context of the limitations
associated with their private nature. To date,
these three typologies have been the focus of
intense debate. However, there are few studies of
the public life that takes place in these spaces, especially when considering that they coexist
simultaneously in the city, claiming a space within
it. This research describes the physical-spatial
and administrative characteristics of these three
cases in order to contribute to the strengthening
of public policies in urban design. Likewise,
commerce is studied in relation to accessibility
patterns at metropolitan level and the types of
markets that aim to attract different users and
promote the public nature of these spaces.https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0718-83582018000100089&lng=en&nrm=iso&tlng=e
Fish Welfare in Urban Aquaponics: Effects of Fertilizer for Lettuce (Lactuca sativa L.) on Some Physiological Stress Indicators in Nile Tilapia (Oreochromis niloticus L.)
The combination of hydroponics and aquaculture, or aquaponics, normally requires adding fertilizer to recirculated water to ensure optimal plant growth, but the effect of that fertilizer on fish welfare has not been studied in detail, especially for small urban and coupled aquaponic systems. In this study, a commercial fertilizer was placed in two small aquaponic systems (less than 250 liters each) to test its effect on the stress levels of Nile tilapia (Oreochromis niloticus) compared to controls without any fertilizer. Fish production parameters were not significantly different between treatments, nor were physiological indicators of fish stress (plasma cortisol, glucose, and triglycerides). On the other hand, lettuce growth (leaf and root weight and length) was up to three times higher in the treatment that received fertilizer. © 2022 by the authors. Licensee MDPI, Basel, Switzerland
Higher vertical jumping asymmetries and lower physical performance are indicators of increased injury incidence in youth team-sport athletes
To date, the literature looking at the association between injury-risk factors and actual injury incidence in young elite team-sports athletes is scarce. The main objective of the present study was to examine how modifiable factors may affect injury incidence. Eighty-one young elite team-sports athletes (age: u-14 to u-18) performed the countermovement jump (CMJ), a single leg CMJ (SLCMJ), the one-legged hop test (OLHT), a 30 m sprint test, the v-cut test, a repeated sprint ability and the 30-15 intermittent fitness test during the pre-season period. Inter-limb asymmetries were calculated for SLCMJ and OLHT. Injuries were recorded prospectively for the entirety of the 2017-2018 season. Comparison of injury and non-injury data was carried out using a two-way analysis of variance (ANOVA). Results of the ANOVA according to injury showed significant differences in CMJ (p = 0.01), SLCMJ on the lowest performing limb (p = 0.03) and SLCMJ asymmetry (< 0.001). Sex*injury interaction was significant from CMJ (p = 0.018) and 30-15 IFT (p = < 0.001). In conclusion, the current study indicated that athletes with greater inter-limb asymmetries, less vertical jump capacity and lower intermittent aerobic fitness had a greater predisposition to injury. Therefore, monitoring CMJ, aerobic performance and inter-limb asymmetries is recommended given their sensitivity to detect significant differences between injured and healthy youth athletes
Respuesta fisiológica al estrés agudo en conejos alimentados con dietas enriquecidas con ácidos grasos poliinsaturados n-3
A total of 700 kits were randomly distributed in flatdeck
group cages avoiding litter effect. They were fed 2
isofibrous, isoenergetic and isoproteic diets formulated
with 2 different sources of fat: mixed fat (control group,
C, n=350) and a supplement of salmon oil rich in
polyunsaturated fatty acids (PUFAs) n-3 (PUFA group, P,
n=350)
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