29 research outputs found
Maternal separation in the rat : long-term effects of early life events on emotionality, drug response and neurobiology
Get PDF1. Marmendal, M., Lindqvist A-S., Eriksson, C.J.P., & Fahlke, C. Maternal separation in male and female Wistar offspring: effects on emotionality, ethanol intake and corticosterone levels. Manuscript.
2. Marmendal, M., Roman, E., Eriksson, C.J.P., Nylander, I., & Fahlke, C. (2004). Maternal separation alters maternal care, but has minor effects on behavior and brain opioid peptides in adult offspring. Developmental Psychobiology, 45, 140-152.
3. Marmendal, M., Eriksson, C.J.P., & Fahlke, C. Early deprivation in male Wistar offspring. Part 1: Long-term increased locomotion and exploratory behavior in novel settings. Manuscript submitted for publication.
4. Marmendal, M., Eriksson, C.J.P., & Fahlke, C. Early deprivation in male Wistar offspring. Part 2: Further evidence for long-term reduced emotionality in novel settings. Manuscript submitted for publication.Exposure to early stress and emotional trauma in humans are associated with an increased risk to develop psychiatric disorders, for example, anxiety, depression and drug abuse. Furthermore, disruptions in stress hormone and neurotransmitter levels as well as structural changes in the brain have been connected to early adversities. Animal models have been developed to experimentally investigate early experiences. In the rat, maternal separation of pups in early ages have been linked to anxiety-related behavioral, endocrinological and neurochemical disruptions in the rat. The aim of the thesis was to investigate these proposed disruptions in pups exposed to repeated maternal separation (MS; 3-4 h/day) during the first two weeks in life relative to controls exposed to brief (3-5 min) daily handling procedure. Behaviorally, anxiety-related behaviors, voluntary alcohol intake and sensitivity to amphetamine were investigated in adult Wistar rat offspring. Furthermore, brain opioid peptides, monoamines, corticosterone levels and weight of adrenal and thymus glands were measured. When separating pups as intact litters kept in incubators, there were mainly no alterations in emotionality, amphetamine-induced locomotor activity, opioid peptide levels or in plasma corticosterone levels in MS offspring, either in males or females. Alcohol intake was, however, intitially decreased in MS females, although total alcohol intake for one week was not affected. When separating pups in intact litters, MS males showed increased weight of adrenal glands, which may reflect a disruption of the HPA axis. When changing the experimental protocol, and separating pups in isolation, the manipulation caused decreased anxiety-related behavior in the offspring. Animals that experienced a temperature challenge while separated (i.e. isolated in room temperature instead of isolated in incubators) showed even more signs of decreased emotionality. There were no significant changes in alcohol intake or in brain monoamine and plasma corticosterone levels compared to controls with this protocol. Maternal care behavior has been reported to be disrupted by prolonged separation episodes. However, when studying the dams’ retrieval behavior of the pups in the present thesis, no negative effects were observed. With respect to the MS protocols used in the present thesis, the results do not provide support for the suggestion that MS manipulations causes enhanced anxiety or disruptions in endocrinology and neurochemistry in the adult rat. These findings could reflect a parallel to human conditions as relatively good psychosocial functioning is sometimes seen despite serious adverse experiences in childhood
Formal Abstraction of Stochastic Systems: Bringing Theory into Practice
No full textRecent developed theories in the field of formal abstraction of stochastic systems have provided new methods for solving the safety and reach-avoid problems. These new methods have been extended to fit controlled stochastic systems, resulting in a policy that optimizes the safety and reach-avoid probabilities. The goal of this thesis is to put all these methods into practice by integrating them in one Graphical User Interface. Practical issues involving limitations on computation time and data storage are addressed. These issues have led to the creation of new theories regarding the abstraction process. This thesis puts forward innovative and efficient ways to calculate the abstraction error. This efficient implementation of the newly developed theories increases their applicability in academic research. A case study is presented to show the possibilities and validity of the developed Graphical User Interface.Delft Center for Systems and ControlMechanical, Maritime and Materials Engineerin
Fixed Channel Road link
No full textA fixed road link between Dover and Calais can be realized by a tunnel, a bridge or The tunnel can be bored which are submerged into a combination of bridge and tunnel or constructed of concrete elements place.Offshore technologyHydraulic EngineeringCivil Engineering and Geoscience
A study on uncertainty in the design of river training works: And the development of a method and instruments to improve a full and consistent use of probabilistic design methods
No full textThe objective of this study is to make a study on dealing with uncertainty in the design of river training works. Based on this study, a method and several instruments have been developed that aim to improve a full and consistent use of a probabilistic design approach. This study is divided into three parts. The outline is rather unconventional for a civil engineering thesis and some of the subjects treated are more related to Information Logistics and Data Management than to typical constructional aspects of civil engineering structures. But since information has become a vital asset for almost every company, in particular for an engineering consultant, it seems a very relevant aspect to study. The first section is a general introduction to the types of uncertainty that have to be dealt with in the design of engineering structures and to the method that is used to incorporate these uncertainties: the probabilistic design approach. In a brief discussion of this approach, two of the main constraints for this approach are introduced: 1. One of the main difficulties is the statistical description of parameters in case of limited available data. These descriptions are used in the probabilistic calculations. If hardly any information is available or only a 'practical' design model is available, does it make sense to apply a probabilistic design approach? 2. Another important aspect is that probabilistic calculations and sensitivity analyses can be very timeconsuming. Because many design studies have a limited time-schedule, this can prevent a full use of these methods. Is this inevitable or could certain methods and design instruments be developed that improve this applicabihty? In the second section part of the first question is analysed by comparing the design results of three similar projects, in which river training works were designed. Two of these projects used a probabilistic design approach, the third one a deterministic approach. In a deterministic approach the safety is not quantified, in a probabilistic design approach, the probabilities of failure of all components of the structure are explicitly determined. The design dimensions of the structures designed in the three projects were likely to be different because of differences in natural conditions, required safety and the design models used. The objectives of this section are to study how the probabibstic design method was applied in the two projects, to study how the uncertainty of the parameters were determined and to quantify the influence of the differences in natural conditions, required safety and used models on the differences in the final designs. In the third section, the design process of an ongoing project is analysed in order to study the second question posed in section I. The ongoing project is the Mekong River Bank Erosion Study which will be used as a reference and case study. The objective of this section is to develop a method and instruments to improve the incorporation of uncertainty in the design. First the methods of determining the uncertainties of observed and derived parameters are studied. Next, the way in which the information about these parameters is managed, communicated and used is discussed. Finally, a design model is proposed in which probabilistic calculations can be made on every required level of detail, using one single software program.Hydraulic EngineeringCivil Engineering and Geoscience
Guyed tower offshore windmill
No full textA guyed tower offshore windmill has been designed to utilize the much higher wind energy production possible there in comparison to onshore. It will be sited in an intermediate water depth (=75 m) of a coastal region. The feasibility for North Sea conditions for a structure with a life of 25 years has been examined. A modified design, slender and light to limit load and mass, of a typical guyed tower has been chosen. Wind and hydrodynamic forces from one direction have been taken into account to determine the static and dynamic load on the truss structure. Wind forces on the turbine rotor have been taken from an earlier study (Lange, 1983).Offshore EngineeringHydraulic EngineeringCivil Engineering and Geoscience
III.—<i>The Roof-bosses in Canterbury Cathedral</i>
No full textThe heraldry of the bosses in the cloisters at Canterbury has been very fully dealt with by our Fellow Mr. Ralph Griffin in Archaeologia, lxvi, 447 ff.; under his direction photographs were taken of every severy and of a great number of the separate bosses, both the heraldic and the non-heraldic. About 120 out of some 800 were reproduced in Archaeologia and a complete set of the prints is in our library. The heraldic bosses in the Chichele porch were described by the same author in Archaeologia, lxxi, 125, where photographs are given of the twenty-nine shields ot arms that appear on the vaulting.</jats:p
Fire in East Kalimantan: a panoply of practices, views and (discouraging) effects
No full textThis paper describes 1999 research intended to shed light on the causes and effects of the devastating 1997-98 forest fires in East Kalimantan. The author visited six communities and interviewed representatives of several other stakeholders (oil palm plantations, industrial timber plantations, timber companies, local government officials) about the causes and effects of the fires. She describes the traditional fire management techniques known by the Kenyah (a dayak group) in several locations. The fires varied considerably in intensity and damage done, among the communities. But some sustained very severe damage to their environment and suffered serious health consequences (both physical and psychological). The paper concludes by estimating the relevance of ten propositions relating to the likelihood of fire danger to each of the six villages visited
Meetconstructies in de brandingszone: Golf- en stromingskrachten
No full textDit rapport is een onderdeel van een afstudeerrapport over een meetconstructie in de brandingszone. In dit deel wordt onderzocht, hoe golf- en stromingskrachten op een slanke constructie in de brandingszone berekend kunnen worden. In het eerste hoofdstuk wordt een algemene beschrijving van golven en golfkrachten gegeven. In het tweede hoofdstuk wordt aan de hand van de lineaire golftheorie en eenvoudige aannames gepoogd een indruk te krijgen van de grootte en het veranderen in de ruimte van de golfkrachten uit de Morison vergelijking. Bij een vergelijking met enige andere theorieen blijken er grote verschillen te zijn tussen de uitkomsten. In de hoofdstukken drie en vier wordt een vergelijking gemaakt met beschikbare laboratoriummetingen. Eerst wordt aandacht besteed aan de schatting van het snelheidsprofiel. Vervolgens worden ook metingen van krachten geanalyseerd. Hierbij komt ook de golfklap ter sprake. In hoofdstuk vijf wordt een beschouwing gegeven over de toepasbaarheid van de laboratoriumresultaten in de natuur, o.a. aan de hand van natuurmetingen. Tenslotte worden in de hoofdstukken zes en zeven resp. een samenvatting een enkele aanbevelingen gepresenteerd.vloeistofmechanicaHydraulic EngineeringCivil Engineering and Geoscience
Inhibition of testosterone biosynthesis by ethanol: relation to the pregnenolone-to-testosterone pathway
No full textAbstractThe concentrations of metabolites in the pregnenolone → testosterone pathway were determined in freezestopped testes in control rats and during ethanol intoxication (2 h after injection of 1.5 g ethanolkg body wt). Ethanol lowered the mean testicular concentrations of testosterone (by 63–74%), androstenedione (49–81%), 17-hydroxyprogesterone (60–76%), progesterone (29–67%) and pregnenolone (12–25%). 4-Methylpyrazole had no effect on the ethanol-induced changes. The present results reveal no inhibition at the 17-hydroxyprogesterone → androstenedione → testosterone steps, but do not exclude inhibition before the step yielding pregnenolone and at the pregnenolone → progesterone → 17-hydroxyprogesterone steps
