The thesis describes infrared radiation and dust properties of the Magellanic Clouds, together with comparisons with emission at other wavelength regimes. Observations of the SMC and LMC were made... Show moreThe thesis describes infrared radiation and dust properties of the Magellanic Clouds, together with comparisons with emission at other wavelength regimes. Observations of the SMC and LMC were made with the IRAS satellite. Maps are presented at wavelengths of 12, 25, 60 and 100 _m. From these maps a list of discrete infrared sources is extracted. This source list is compared to known object lists (foreground stars, SMC stars, H_ nebulosities, clusters, supernova remnants, planetary nebula and dark clouds). There is a good correlation between HII regions and infrared emission from the SMC. For the LMC a similar presentation and discussion is given as for the SMC. A list of discrete sources is extracted, which is compared to similar source lists. As for the SMC, there is also a very good correlation of the infrared emission peaks with HII regions in the LMC. The Galactic infrared foreground emission is discussed. Foreground filaments disturb the image of this Cloud, and the IRAS data show significant variations in the foreground. The relation between the infrared foreground emission and the atomic hydrogen content is found to be non-linear. An estimate for the foreground infrared emission is derived, based on the average gas-to-dust ratio. The foreground towards the LMC varies from 0.07 to 0.17 magnitude, with an average of 0.10. A more or less constant foreground of 0.08 magnitude towards the SMC is found. Global properties of the Magellanic Clouds are discussed. Integrated infrared flux densities, infrared sizes, infrared luminosities and dust temperatures are derived. The infrared morphology is discussed, together with the temperature distribution. It turns out that the Greater 30 Doradus Region emits about 40 % of all infrared radiation. The density of the interstellar radiation field in the Clouds is derived. On average the fields are 7 times stronger than the Solar Neighbourhood field. A relation is found between infrared emission and the H_ supergiant shells in the LMC. Comparisons of the infrared maps are presented with ultraviolet data, H_ maps and with radio continuum observations. The SMC is 10 to 20 times weaker than the LMC in the infrared. The thesis describes dust properties in the Magellanic Clouds. The mid-infrared (12 and 25 _m) emission in the Clouds is less than that in the Local Group spiral galaxies. It is most likely that very small grains are responsible for this emission. Dust masses are derived for the combined warm (~50 K) and cool (25 K) dust components. The mass present in the cold (15 K) dust component is estimated to be between 1/3 and 1 times the mass of cool dust. Total dust masses of 550000 solar masses for the LMC and 24000 solar masses for the SMC are derived. Dust column density maps are presented for both Clouds. From a comparison of the infrared maps with atomic hydrogen maps, similar non-linear relations are found as for the Galactic foreground. Global properties of the Clouds are discussed in relation with irregular galaxies and in relation with Local Group spiral galaxies. The infrared colours of the Clouds are similar to the colours of other irregular galaxies. There are some exceptions, NGC 6822 and NGC 1569 have much lower f12 _m/f25 _m ratios than the Clouds, but their f60 _m/f100 _m ratios are similar. The luminosity-to-mass ratio of the SMC is similar to that of other irregular galaxies. That ratio of the LMC is an order of magnitude higher, and is comparable to that of spiral galaxies such as IC 342, M101and M33. Relative to the irregular galaxies, the gas-to-dust ratio in the LMC is low. The LMC gas-to-dust ratio is probably not very different from that in M31 and M33. For the LMC a ratio 3 times higher than for the Milky Way is found; for the SMC the ratio is 50 times higher than for the Milky Way. The LMC value agrees well with that of other authors, based on photometric B and V measurements and Ly_ absorption. The SMC value is, however, 3 to 6 times higher than those ratios. This difference is explained by Galactic foreground difficulties in photometric observations: high foreground extinction values from Chapter IV suggest large variations on small scales for individual stars. A new fit is made to the EB-V and NHI data, showing agreement with the dust mass based on infrared data. These findings also agree with the integrated ratio L100 _m/MHI, which is about 30 times lower for the SMC than for the Galaxy. Show less
This study focuses on the factors which determine the size of the breeding population of rabbits, at the end of the winter. The main questions were: What determines the size of the breeding... Show moreThis study focuses on the factors which determine the size of the breeding population of rabbits, at the end of the winter. The main questions were: What determines the size of the breeding population? Do rabbit numbers increase to carrying capacity set by the food, or are they kept below this limit by e.g. intrinsic responses to density or by predation? Show less
The purpose of this study is to discuss several aspects of facioscapulohumeral disease, also called "autosomal dominant facioscapulohumeral muscular dystrophy" or "Landouzy-Dejerine type of... Show moreThe purpose of this study is to discuss several aspects of facioscapulohumeral disease, also called "autosomal dominant facioscapulohumeral muscular dystrophy" or "Landouzy-Dejerine type of muscular dystrophy" or "Landouzy-Dejerine' s disease" . We consider this disorder well defined and recognizable, justifying the term facioscapulohumeral disease, abbreviated FSHD. Show less
De Kapsiki (Kameroen) en de Higi (Noordoost-Nigerie) vormen een etnische eenheid. De afzonderlijke benaming is een gevolg van externe politieke factoren. De auteur verrichtte... Show moreDe Kapsiki (Kameroen) en de Higi (Noordoost-Nigerie) vormen een etnische eenheid. De afzonderlijke benaming is een gevolg van externe politieke factoren. De auteur verrichtte cultureelantropologisch veldwerk onder dit volk. Hij beschrijft het en analyseert de structuur ervan. De geschiedenis van het gebied en de technisch-economische aanpassing van de Kapsiki/Higi zijn verantwoordelijk voor de atomisering van zijn samenleving. De auteur zoekt een antwoord op de vraag hoe een zo geatomiseerde samenleving als die van de Kapsiki/Higi kan functioneren Show less
Hemophilia is a sex linked, recessive, hereditary disorder characterizedby excessive bleeding. This bleeding tendency manifestsitself in spontaneous hemorrhages in the joint cavities and muscles... Show moreHemophilia is a sex linked, recessive, hereditary disorder characterizedby excessive bleeding. This bleeding tendency manifestsitself in spontaneous hemorrhages in the joint cavities and muscles,and in excessive bleeding after trauma or surgical procedures.The first written references to the disease can be found in theBabylonian Talmud, in which it can be read that Rabbi Judah thePatriarch exempted the third son from circumcision if his motherhad already lost two sons because they had bled to death afterthis operation ( 1 ) . Rabbi Simon hen Gamaliel even forbade a boyto be circumcised whien sons of his mother's three elder sisters haddied from bleeding after circumcision ( 2).In the 19th century Wardrop discovered the prolonged clottingtime of hemophilic blood. For a long time lack of prothrombin washeld responsible for the clotting defect until in 1935 Quick foundthat the prothrombin time of hemophilic plasma was normal ( 2) .Patek and Taylor reported in 1937 that the prolonged clottingtime of hemophilic plasma could be normalized by the addition ofa globulin fraction of normal blood. For this reason the lackingclotting component was called antihemophilic globulin; later, byinternational agreement, it was named clotting factor VIII (2).In 1944 Pavlovsky observed that a mixture of the blood of twohemophiliacs known to him had a normal clotting time ( 3, 4). Theright interpretation of this finding was given only in 1952 and notby Pavlovsky himself. In that year reports from New York, SanFrancisco, and Oxford described a disease which was clinically andgenetically undistinguishable from hemophilia, but the lackingclotting component was not factor VIII ( 5-7). The missing factorin this new disorder, PTC-deficiency, Christmas disease or hemophiliaB, was later called factor IX. Show less
In the first part of this essay the development of the study of African history is sketched, and the historical studies written by professional African historians from 1955 to 1972-3 are analysed.... Show moreIn the first part of this essay the development of the study of African history is sketched, and the historical studies written by professional African historians from 1955 to 1972-3 are analysed. Special attention is paid to the manisfestoes of the 1960s, programmatical declarations of what African history should be and how it should be written. Part two traces in detail what historical studis were actually produced in the fifteen years that followed independence in one particular West African country, Nigeria Show less
Focuses upon social interaction patterns in the Housing Estate of Kitale (Kenya). The inhabitants of this low income Housing Estate are sensitive to the same kind of spatial characteristics of... Show moreFocuses upon social interaction patterns in the Housing Estate of Kitale (Kenya). The inhabitants of this low income Housing Estate are sensitive to the same kind of spatial characteristics of housing as are people living under similar conditions in other societies. Both their economic and housing circumstances impose a strain on daily life. The inhabitants react to these circumstances by developing patterns of expectations and behaviour vis-…-vis their neighbours which resemble those of their counterparts elsewhere, despite the cultural and economic differences between societies Show less
Intestinal schistosomiasis is a disease caused by the tre-Schistosoma mansoni (Sambon, 1907). Man is the principal final host of this parasitic worm and the intermediate host is a fresh water snail... Show moreIntestinal schistosomiasis is a disease caused by the tre-Schistosoma mansoni (Sambon, 1907). Man is the principal final host of this parasitic worm and the intermediate host is a fresh water snail. The adult worms, which are some 8-15 mm long, inhabit the portal venous system. There, the females produce large amounts of eggs, many of which are excreted with the faeces. The remaining eggs get stuck in the tissues where they die. As a result of the dead eggs bilharzial granulomas are formed which are the main cause of pathologie changes in the host. The excreted eggs hatch on immersion in water and the escaping miracidia can freely live in the water for several hours. If they succeed in penetrating an intermediate host snail (in Ethiopia; Biomphalaria pfeifferi) a mother sporocyst, several daughter sporocysts, and eventually, after some 4-5 weeks, many cercariae are produced, The phase of asexual multiplication in the snail host results in the production of large numbers of exclusively either male or female cercariae. Only snails that have been penetrated successfully by several miracidia may shed cercariae of both sexes. The free living cercariae have a short life span: most of them die within 24 hours. Man may become infected when his skin is exposed to water containing cercariae. When the cercariae penetrate man's skin they are transformed into schistosomules and in some 40-60 days these schistosomules develop into adult worms that migrate to the portal and mesenteric veins. Then eggs are produced again. Show less
This thesis describes the tropic acid enzymes which in 4 steps catalyze the metabolic pathway of the alkaloid atropine. The enzymes have been discovered in a Pseudomonas bacterium from soil... Show moreThis thesis describes the tropic acid enzymes which in 4 steps catalyze the metabolic pathway of the alkaloid atropine. The enzymes have been discovered in a Pseudomonas bacterium from soil underneath the Atropa belladonna plant, the natural producer of atropine. These 4 enzymes are highly specific and show peculiar kinetics explained by the very asymmetrical equilibrium for step 2 and a keto-enol tautomerism for the product of step 2, the 2-phenylmalonic semialdehyde. The last part concerns the regulation of enzyme synthesis by product induction and its major advantage for cell economy. This thesis was written in the Dutch Language in 1969 and at that time deposited in the Repositorium of the Library of the Technical University, Delft, The Netherlands htpps://repository.tudelft.nl/view/tno; # 268336.Only in 2019 the thesis was translated by the author in English as precise copy nearly page by page of the 1969 version (no update). The English translation is only meant to disseminate the scientific data, described in the Dutch version. It does not intend to add any new data. In case of differences in the interpretation of the intellectual property only the Dutch version counts. Show less