103 research outputs found
A bibliography of tasmanite with an introduction and annotations
Since the discovery of tasmanite in 1851, scientific interest in this oil shale has shown much variation. The recent resurgence of research activity on tasmanite has been occasioned by the availability of new techniques which now permit the organic matter to be examined in considerable detail. This paper presents a summary of the history, nature and chemistry of tasmanite, followed. by a comprehensive bibliography. The survey was prompted by a recent catalogue of Tdsmanites from the palynological viewpoint, and the lack of a similar publication on tasmanite itself. The references are given in alphabetical order, together with an abstract. Additional annotations are made, if pertinent
Nature of Tasmanian oil shale
Since deposition, the organic matter of most oil
shales has been so changed over geological time
that little recognisable features remain. Microscopical
examination does not provide much help
for constitutional analysis and thus one cannot use
biological features as a basis for classification.
Tasmanite oil shale is a notable exception. The
kerogen is so sharply differentiated from the
mineral matrix that it can be largely separated
by mechanical means.
Tasmanite kerogen, when isolated, appears as
flattened discs, which, by various sectioning processes,
can be shown to have been nearly spherical
in shape before compaction. There has been a
great deal of argument as to the exact nature of
these dissemenules. The century-old suggestion,
originally rejected, that they are algal in origin
has now been generally accepted and it may be
taken that Tasmanites, as it occurs in oil shale,
represents the cyst stage of a peculiar alga belonging,
most likely, to the Chlorophyceae. The exact
relationship within the family is still uncertain.
Because of its discrete and peculiar structure, it
might be assumed that the organic matter of tasmanite
has a chemistry different from other algal
shales. This is true only in so far as the soluble
resin-like material is concerned, the pyrolysate
possesses a normal hydrocarbon chemistry, although
the non-hydrocarbon constituents are somewhat
more than usual. Infrared and other physical
methods of analysis support this hypothesis
"Oil" on Flinders Island
A survey has been made of the alleged occurrence
of petroleum on Flinders Island, Bass Strait. An
investigation of the material purporting to be
petroliferous, has shown it to be a curious comminuted
organic mass of plant detritus, apparently
formed under unusual conditions.
The paludine "oil", and that produced by
pyrolysis of the semipeat, is not related to mineral
oil in any way. It is, on the contrary, a resinous,
viscid decomposition product, composed of phenols,
waxy esters, resins and an indefinite variety of
organic residuals, to which the name plant adipocere
might well be applied
The effects on grain quality traits of a grain serpin protein and the VPM 1 segment in southern Australian wheat breeding
Trabalho final do 6º ano médico com vista à atribuição do Grau de Mestre no âmbito do ciclo de estudos de mestrado integrado em medicina da Faculdade de Medicina de Coimbra.Introdução: Estudos prévios estabeleceram que até 12% dos doentes com enfarte agudo do
miocárdio não demonstravam lesão coronária aparente ao exame angiográfico. Contudo,
existe muito pouca informação disponÃvel acerca deste fenómeno em enfartes agudos do
miocárdio sem elevação do segmento ST. O objectivo deste estudo foi avaliar uma população
de doentes com esse diagnóstico sujeitos a angiografia coronária, analisando e comparando as
caracterÃsticas clÃnicas e os prognósticos entre os que não revelaram lesão coronária aparente
e os que apresentavam doença coronária epicárdica.
Métodos: O nosso estudo avaliou 270 doentes com enfarte agudo do miocárdio sem elevação
do segmento ST que foram sujeitos a angiografia coronária nas primeiras 72 horas de enfarte.
Foram valorizadas as caracterÃsticas demográficas, clÃnicas, parâmetros analÃticos, achados
electrocardiográficos, fracção de ejecção ventricular esquerda, duração do internamento e
prognóstico.Previous studies established that up to 12% of patients with acute myocardial
infarction did not present coronary atherosclerotic disease demonstrable with angiographic
exam. However, little information is available about this phenomenon in acute non-STelevation
myocardial infarction. We examined a population of patients with this diagnosis
who had undergone coronary angiography, assessing and comparing the clinical
characteristics and prognosis between the subset of patients with angiographically normal
coronary arteries and the subset of patients with coronary disease
The effects on grain quality traits of a grain serpin protein and the VPM 1 segment in southern Australian wheat breeding
Circulating Strains of Human Respiratory Syncytial Virus in Central and South America
Human respiratory syncytial virus (HRSV) is a major cause of viral lower respiratory tract infections among infants and young children. HRSV strains vary genetically and antigenically and have been classified into two broad subgroups, A and B (HRSV-A and HRSV-B, respectively). To date, little is known about the circulating strains of HRSV in Latin America. We have evaluated the genetic diversity of 96 HRSV strains by sequencing a variable region of the G protein gene of isolates collected from 2007 to 2009 in Central and South America. Our results show the presence of the two antigenic subgroups of HRSV during this period with the majority belonging to the genotype HRSV-A2
Meiosis-Specific Stable Binding of Augmin to Acentrosomal Spindle Poles Promotes Biased Microtubule Assembly in Oocytes
In the oocytes of many animals including humans, the meiotic spindle assembles without centrosomes. It is still unclear how multiple pathways contribute to spindle microtubule assembly, and whether they are regulated differently in mitosis and meiosis. Augmin is a γ-tubulin recruiting complex which "amplifies" spindle microtubules by generating new microtubules along existing ones in mitosis. Here we show that in Drosophila melanogaster oocytes Augmin is dispensable for chromatin-driven assembly of bulk spindle microtubules, but is required for full microtubule assembly near the poles. The level of Augmin accumulated at spindle poles is well correlated with the degree of chromosome congression. Fluorescence recovery after photobleaching shows that Augmin stably associates with the polar regions of the spindle in oocytes, unlike in mitotic cells where it transiently and uniformly associates with the metaphase spindle. This stable association is enhanced by γ-tubulin and the kinesin-14 Ncd. Therefore, we suggest that meiosis-specific regulation of Augmin compensates for the lack of centrosomes in oocytes by actively biasing sites of microtubule generation within the spindle
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