Search results for " Vertical"
showing 10 items of 163 documents
Size distribution of Daphnia longispina in the vertical profile
1997
D. longispina of the meromictic lake El Tobar is a round-headed form. It never has a helmet, but in summer a small proportion of immature individuals (0.9–1.2 mm females and males) have one or two neck teeth. The size structure of this Daphnia population, as well as the vertical distribution and migration of different size-classes, were studied in September and November of 1991 and April of 1992. The large variation in mean size and size at first reproduction, as well as the occurrence of different patterns of vertical migration are interpreted as responses to different predator situations. At the end of April, when Daphnia mortality by visually hunting predators is dominating, a typical no…
Diel vertical migration by Daphnia longispina in a Spanish lake: Genetic sources of distributional variation
1995
Individuals of many zooplankton species undergo diel vertical migration in which they move toward the surface after sunset and return to deeper waters at dawn. However, even when vertical migration can be clearly demonstrated by mapping the distributions of individuals at noon and midnight, at any given time the population is usually scattered over ‘a broad range of depths. This paper focuses on a major potential source of the variance associated with depth distributions. We have used electrophoretic analysis of isozymes to identify “clones” of Daphnia longispina in a Spanish lake. In September 199 1, two clones constituted 5 5% of the individuals collected at noon and midnight on each oftw…
Diel feeding periodicity, daily ration and prey selectivity in juvenile brown trout in a subarctic river
1999
Feeding of age-1 brown trout Salmo trutta in a third-order river in northern Finland was usually highest in the twilight hours and lowest around midday. Diel periodicity in food intake was less distinct and rarely significant for age-0 trout. Daily rations declined seasonally, being lowest in October, and highest in June (age-1 trout) or early August (age-0 trout). Prey selection did not differ between day and night, but differences between age classes and sampling dates were distinct. Age-0 trout preferred Ephemerella nymphs in summer and Micrasema larvae later in the season. Age-1 trout fed selectively on caddis larvae on all sample dates. Aerial insects and Baetis nymphs were avoided by …
Construyendo el espacio geográfico a partir del mundo subjetivo de los alumnos
2014
El presente trabajo se enmarca dentro de la geografía subjetiva. A través de un estudio de caso se observa cómo las experiencias personales de los niños y niñas influyen en la construcción y en la deformación del espacio geográfico. Este documento puede servir de orientación para poner en práctica un proyecto de innovación, pues se ofrece una secuencia de actividades donde se trabaja el conocimiento y la autonomía espacial. This work is part of subjective geography. A case study shows how children's personal experiences influence the construction and deformation of geographic space. This may provide guidance to implement an innovation project. The series of activities which are proposed wor…
SVILUPPO E INTEGRAZIONE DI FILIERA. IL FUTURO DELL’IMPRESA ITTICA SICILIANA
2015
Le attività dell’impresa che opera nel settore ittico non dipendono solo dalla sue capacità e dalle sue strategie, ma sono influenzate, direttamente o indirettamente, anche dalle azioni dei diversi attori che operano all’interno della filiera in cui essa opera. Il presente contributo prende in esame brevemente il ruolo di tali attori in Sicilia per poi proporre due casi studio, quello del Progetto Manifattura di Rovereto e quello del Fisch Markt di Amburgo come esempi a cui ispirarsi nell’incentivazione dei processi di integrazione della filiera ittica siciliana e nella prospettiva del superamento di una logica di mera “sopravvivenza” delle sue imprese. The activities of the company that op…
Estudio retrospectivo a largo plazo de los resultados de dos técnicas de cirugía bariátrica en pacientes con obesidad mórbida: Bypass gástrico y gast…
2020
La obesidad mórbida (Índice de Masa Corporal >40) se asocia a comorbilidades que pueden poner en riesgo la vida del paciente. El bypass gástrico en “y de roux” y la gastrectomía vertical son dos de las técnicas bariátricas más realizadas, pero, aunque se postulen como tratamientos eficaces frente a esta obesidad, no están exentas de riesgo. El objetivo principal de este estudio es conocer los efectos que estas técnicas tienen sobre el paciente a medio-largo plazo (2-5 años) siendo los seguimientos a los 0, 6, 12, 24 y 60 meses. Se realiza un estudio observacional retrospectivo y comparativo de una muestra de 244 pacientes (133 intervenidos mediante by pass gástrico en “y de roux” y 111 medi…
Pattern and rate of post-20 ka vertical tectonic motion around the Capo Vaticano Promontory (W Calabria, Italy) based on offshore geomorphological in…
2014
The magnitude and rate of Late Pleistocene-Holocene vertical tectonic movements offshore of the Capo Vaticano Promontory (western Calabria, southern Italy) have been measured on the basis of the present-day depth variations of the edges of submerged depositional terraces (and associated abrasion platforms) that formed below the storm-wave base, during the sea level stillstand of the Last Glacial Maximum (LGM). These depositional features, represented by submerged prograding wedges and an associated terrace-shaped upper boundary, have been identified in high-resolution seismic reflection profiles acquired along the continental shelf and the upper slope of the promontory, and are referred to …
Diel variability in counts of reef fishes and its implications for monitoring
2006
Studies of reef fish assemblages in space rarely consider the effects of temporal variability on spatial comparisons, and when they do, usually examine timescales of months to years. The nature of fish monitoring surveys is such that particular locations may be surveyed at one time of day, and surveys designed to establish the degree of spatial variability in assemblages may be confounded if the order of sampling within treatments is not randomised with respect to time of day. In this study, we tested the degree of temporal variability in temperate reef fish counts at the same sites in New Zealand and Italy, within and between days. Repeated counts separated by months returned quite differe…
Effect of vertical loads on lateral response of infilled frames
2004
Demo 168. Demostración de la ley de Raoult y de la nucleación heterogénea con un frasco de Franklin vertical
2021
Se presenta una demostración de aula que muestra que la condensación del vapor se produce preferentemente sobre la superficie de partículas sólidas y que la presión de vapor de una disolución disminuye cuando aumenta la concentración de soluto. A classroom demonstration is presented showing that vapor condensation occurs preferentially on the surface of solid particles and that the vapor pressure of a solution decreases as the solute concentration increases.