326 research outputs found
Vein or trachea first? A comparative and genetic study to test the hypothesis of the pleural gill origin of the insect wing
Motivation: How insect wings emerged as an evolutionary novelty that permitted the extraordinary radiation and diversification among insects is a long-standing question that remains unanswered. The fossil record suggests that the first wings evolved in aquatic insects from respiratory gills, lateral movable flat pads articulated with the trunk pleural (lateral) region (1). Extant representatives of these flying insect ancestors are the Ephemeropterans, or mayflies. Still today, their aquatic nymphs bear gills along the abdominal segments. Extant wings are formed by a bilayered epithelial wing span. Rigidity is conferred by veins, epithelial thickenings that form hollow tubes that radiate along the proximodistal wing axis. Veins allow the flow of hemolymph and are traversed by trachea (respiratory tubes) and nerves (2) coming from sensory organs distributed along the wing margin or present on the veins. Therefore, the routes taken by trachea and nerves coincide with the veins. In the model organism, veins are genetically specified early, before any trachea invade the wing. Therefore, anatomical and genetic information seem to indicate that veins would be required for trachea and sensory organs to develop (i.e. veins come first). However, mayfly gills are invaded by branching trachea and have a number of sensory (and osmoregulatory) organs along the margin and on its surface, and yet they show no signs of veins. Therefore, is the gills were the ancestors of the wings, either gills from extant species lost the veins, or tracheal invasion of the wing does not depend on veins –although their precise routes might depend on where veins are.Methods: To address this question we made comparative studies between Cloeon dipterum, and two dipteran species, Drosophila melanogaster and Episyrphus balteatus using immunostainings and fly genetics.Results and Conclusions: In this work, I set to first, describe the tracheal invasion of the developing wing in Drosophila and two other species, another fly (Episyrphus balteatus) as well as in the mayfly Cloeon dipterum, to compare it to the development and pattern of tracheal invasion in Cleon’s gills. Second, using a genetic approach, I test the mutual dependencies between trachea, veins and nerves for their establishment. If the wing originated from tracheated movable gills without vein tracks, wing trachea in Drosophila should be able to invade tthe developing wing without genetically defined veins
Estudio de un caso de marca sostenible: 198. La RSC como estrategia de valor de marca
Estudio de caso de la marca Uno Nueve Ocho, autodefinida como sostenible y con una fuerte política de RSC que busca respetar al medio ambiente así como a los trabajadores, con quienes interactúan durante todo el proceso. El objetivo del estudio es valorar la coherencia de una marca autodefinida como responsable con el discurso de su comunicación de marca (web, blog...) y el discurso de la dirección empresarial.Grado en Publicidad y Relaciones Pública
Estudio de la influencia de las redes de comunicación en las redes inteligentes de energía
Las Redes Inteligentes de Energía (RRII) deben garantizar la calidad y la disponibilidad de energía, así como los nuevos servicios destinados a los usuarios finales y a las compañías eléctricas. El soporte básico de las RRII son los sistemas de comunicación, cercanos al tiempo real, entre los sistemas de generación, consumo y control de la red eléctrica.
Esta tesis aborda, en primera instancia, un estudio sobre las necesidades de comunicaciones en los diferentes ámbitos de las RRII y las características de ancho de banda y latencia necesarias para dar soporte a la gran variedad de casos de uso que se pueden contemplar.
La problemática del modelado de los diferentes canales y medios físicos habituales en las comunicaciones de las RRII es siguiente objetivo de esta tesis. Cada canal tiene unos parámetros característicos que es preciso cuantificar, para analizar su idoneidad para los diferentes ámbitos de comunicación y funciones dentro de la red inteligente. La latencia, el ancho de banda, la variabilidad de estos a lo largo del tiempo y la disponibilidad, deben cumplir unos requisitos mínimos en función del ámbito de red y el caso de uso al que se destine. Se muestra cómo los parámetros de cada canal pueden ser modelados en el caso de que la red de datos sea conocida. Además, dado que en la mayoría de los casos la red de datos es heterogénea y compuesta de diferentes medios, en este trabajo, amén de analizar el comportamiento de los canales de comunicación más utilizados en las RRII, se propone un método de análisis que permite derivar las características principales del canal de comunicaciones.
En última instancia, esta tesis recoge un análisis de la influencia de las comunicaciones en dos casos de uso de gran importancia en las RRII, proponiendo y diseñando un entorno de pruebas, una metodología de análisis propia y ofreciendo alternativas para solventar los problemas que las comunicaciones introducen. En el primero ellos se estudia la influencia de las comunicaciones en los índices de calidad de la red eléctrica de distribución. El segundo caso aborda la influencia de las comunicaciones en el control, dentro de una red de área extensa, de un compensador estático trabajando como sistema de soporte de red eléctrica
A neurocognitive model for short-term sensory and motor preparatory activity in humans
The
purpose
of
this
review
is
to
present
information
from
different
experiments
that
supports
the
proposal
that
brain
systems
are
able
to
predict,
in
a
short-term
interval,
certain
characteristics
about
the
next
incoming
stimuli.
This
ability
allows
the
subject
to
be
ready
for
the
stimuli
and
be
more
efficient
in
completing
the
required
task.
Evidence
is
presented
from
different
sensory-motor
experiments,
such
as
the
central
cueing
Posner
paradigm;
Contingent
Negative
Variation
(E1-E2),
spectral
modulation
during expectancy and Lateralized Readiness
Potential
during
the
first-order
sequential
effect.
Some
cases
from
motor
experiments
are
also
presented,
such
as
express
saccades,
the
manual
gap
paradigm
and
ocular
smooth
pursuit
movements.
All
these
data
support
a
neurocognitive
model
that
can
be
related
to
neuroanatomical
structures
whose
connections
have
been
well-
established.
In
the
final
section,
a
possible
algorithm
that
explains
the
selection of a preparatory set among the alternatives is discussed
Badajoz: ciudad amurallada. El progreso contra el baluarte de San Juan
El presente artículo está basado en uno de los aspectos desarrollados por el autor en su Tesis Doctoral “Desarrollo intrarnuros de la ciudad de Badajoz: I939-1979”, defendida en la Escuela Técnica Superior de Arquitectura de Sevilla en 1991.En este artículo se expone cómo se demolieron algunas fortificaciones, como el baluarte de San Juan, en 1964, para facilitar el crecimiento urbano de Badajoz. Se define como una ciudad amurallada mediante los datos y documentos existentes, pero cuyo desarrollo urbano a partir de los años 60 del siglo pasado dio lugar a que unos amurallamientos que eran completos y se encontraban en buen estado hacia 1940 casi desaparecieran o se ocultaran en los años 70. Se concluye que la demolición del baluarte de San Juan no sólo no sirvió para fomentar el progreso en la ciudad de Badajoz, sino que contribuyó (junto con otras causas) a la degradación del casco histórico, provocando el desplazamiento del centro urbano en detrimento de la parte alta del recinto amurallado.This paper shows how some fortifications were demolished, such as the bastion of St. John, in 1964, to facilitate the urban growth of Badajoz. It is defined as a walled city through existing data and documents, but whose urban development from the 60s of the last century resulted in some walls that were completed and in good conditions around 1940, almost disappeared or were hidden in the 70s. It is concluded that the demolition of the bastion of St. John not only did not serve to promote progress in the city of Badajoz, but contributed (along with other causes) to the degradation of the historic center, causing the displacement of the urban center in detriment of the upper part of the walled enclosure.peerReviewe
Casas precocinadas.
Ante la situación actual y esperanzadora con la aparición de empresas que lideran la imagen del hogar bajo productos de mercado económicos, el propósito de este trabajo de investigación es explicar las posibilidades reales que tiene de materializarse un ideal que a lo largo de la mitad del siglo XX ilustraron muchos de sus arquitectos en diversos proyectos bajo el conocido nombre de Plug-in, consistiendo en la composición de un edificio que por un lado es una estructura y por otro módulos habitables prefabricados. Viéndolo como una solución para una vivienda plurifamiliar más económica, mejor terminada, sostenible y fundamentalmente más flexible a las exigencias de sus moradores.Universidad Pablo de OlavideMinisterio de Ciencia e Innovación CSO2009-06819-EUniversidad de Granada 1975-200
Does the midbrain dorsolateral periaqueductal grey have direct connections with the pontine A5 region? A neuropharmacologic and electrophysiological study
This study has been performed in spontaneously breathing anesthetised rats. We have analysed the possible interactions between the midbrain dorsolateral periaqueductal grey matter (dlPAG) and the pontine A5 region. Electrical stimulations of the dlPAG (1 ms pulses, 20-30 μA given at 100 Hz for 5s) were elicited and the evoked cardiorespiratory changes were analysed before and after ipsilateral blockade of the neurotransmission within the A5 region by means of microinjections of muscimol (50 nl, 0.25 nmol, 5s). Electrical stimulations evoked the classical “defence response” characterized by tachipnoea, hypertension and tachycardia. Tachipnoea consisted of an inspiratory facilitatory response [increase in respiratory rate (p<0.001) due to a decrease in expiratory time (p<0.01)] and was accompanied by a pressor (p<0.001) and tachycardic (p<0.001) response. Muscimol microinjected within the A5 region reduced pressor (p<0.05), tachycardic (p<0.001) and tachypnoeic (p<0.001) responses evoked to dlPAG electrical stimulations. Finally, in order to assess functional interactions between A5 and dlPAG, extracellular recordings of 40 putative A5 cells during dlPAG electrical stimulation were recorded. 16 cells were affected by dlPAG stimulation (40%). 3 cells showed orthodromic activation (14.2 ± 1.7 ms). 5 cells were excited (10.1 ± 1.6 ms). 7 cells decreased spontaneous activity to dlPAG stimulation. 24 cells were not modified by dlPAG stimulation (2 presented a respiratory pattern and 1 presented a cardiovascular pattern).
These results contribute with new data on the role of the A5 region neurones in the modulation of the cardiorespiratory response evoked on dlPAG stimulation.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
Dorsolateral periaqueductal grey matter and pontine A5 region connectivity: a neuropharmacologic and electrophysiological study
In this study, carried out in spontaneously breathing anesthetised rats, we have analysed the relevance of the interactions between the dorsolateral periaqueductal grey matter (dlPAG) and the A5 region, and how this sympathetic pontine region participates in modulating the cardiorespiratory response evoked from the dlPAG. Electrical stimulation of the dlPAG (1 ms pulses, 20-30 μA given at 100 Hz for 5s) was elicited, and the evoked cardiorespiratory changes were analysed before and after ipsilateral microinjections of muscimol (50 nl, 0.25 nmol, 5s) within the A5 region. DlPAG stimulation evoked the classical “defence response” characterized by tachipnoea, hypertension and tachycardia. Tachipnoea consisted of an inspiratory facilitatory response [increase in respiratory rate (p<0.001) due to a decrease in expiratory time (p<0.01)] and was accompanied by a pressor (p<0.001) and tachycardic (p<0.001) response. Microinjection of Muscimol within the A5 region reduced all, pressor (p<0.05), heart rate (p<0.001) and respiratory (p<0.001) responses evoked by electrical stimulation of dlPAG. Finally, extracellular recordings of putative A5 neurones were obtained during dlPAG electrical stimulation in order to assess functional interactions between A5 and dlPAG. Forty A5 cells were recorded, 16 of which were affected by dlPAG (40%). With these results, we can conclude that neurones of the A5 region possibly modulate the cardiorespiratory response evoked from the dlPAG.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
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