972 resultados para ESSENTIAL SPECTRUM OF SEMIGROUP
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A new heterocycle, namely 2-(furyl)-3-(furfuralimino)-1,2-dihydroquinazolin-4(3H)-one (ffdq) was formed by the ondensation of 2-aminobenzoylhydrazide with furfural and characterized by physico-chemical, spectroscopic, and single crystal X-ray diffraction studies. A series of complexes of ffdq have been synthesized and characterized by physico-chemical, spectroscopic, and thermal studies. According to the i.r. and 1H-n.m.r. spectra ffdq behaves as a bidentate ligand coordinating through quinazoline oxygen and azomethine nitrogen. The FAB-mass spectrum of the Cd(II) complex indicates the monomeric nature of this complex. The X-band e.p.r. spectrum of the Cu(II) complex and thermal stabilities of the Co(II) and Ni(II) complexes are discussed.
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Oxygen release accompanying oxidation of vanadyl by diperoxovanadate was suppressed on addition of NADH. The added NADH was rapidly oxidized, oxygen in the medium was consumed, and the reaction terminated on exhaustion of either NADH or vanadyl. The consumption of oxygen and disappearance of NADH needed small concentrations of diperoxovanadate to initiate and increased with increase in the concentration of vanadyl and NADH or decrease of pH. The products of the reaction were found to be NAD(+) from NADH and vanadate oligomers from vanadyl and oxygen. The reaction was insensitive to catalase and was not dependent on H2O2. The reaction was inhibited by superoxide dismutase, cytochrome c, EDTA, Mn2+, histidine, and DMPO, but not by hydroxyl radical scavengers such as ethanol and benzoate, The ESR spectrum of the reaction mixture showed the presence of the 1:2:2:1 quartet signal typical of a DMPO-OH adduct, but this was not modified by ethanol, This oxygen radical species, possibly of (OV)-O-. type derived from diperoxovanadate, is proposed to have a role in the reactions of oxygen release and NADH oxidation
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The genomic sequences of several RNA plant viruses including cucumber mosaic virus, brome mosaic virus, alfalfa mosaic virus and tobacco mosaic virus have become available recently. The former two viruses are icosahedral while the latter two are bullet and rod shaped, respectively in particle morphology. The non-structural 3a proteins of cucumber mosaic virus and brome mosaic virus have an amino acid sequence homology of 35% and hence are evolutionarily related. In contrast, the coat proteins exhibit little homology, although the circular dichroism spectrum of these viruses are similar. The non-coding regions of the genome also exhibit variable but extensive homology. Comparison of the brome mosaic virus and alfalfa mosaic virus sequences reveals that they are probably related although with a much larger evolutionary distance. The polypeptide folds of the coat protein of three biologically distinct isometric plant viruses, tomato bushy stunt virus, southern bean mosaic virus and satellite tobacco necrosis virus have been shown to display a striking resemblance. All of them consist of a topologically similar 8-standard β-barrel. The implications of these studies to the understanding of the evolution of plant viruses will be discussed.
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Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in 25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16 regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP, while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium (LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region. Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa, an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent signals within the same region.
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Photometric and spectral evolution of the Type Ic supernova SN 2007ru until around 210 days after maximum are presented. The spectra show broad spectral features due to very high expansion velocity, normally seen in hypernovae. The photospheric velocity is higher than other normal Type Ic supernovae (SNe Ic). It is lower than SN 1998bw at similar to 8 days after the explosion, but is comparable at later epochs. The light curve (LC) evolution of SN 2007ru indicates a fast rise time of 8 +/- 3 days to B-band maximum and postmaximum decline more rapid than other broad-line SNe Ic. With an absolute V magnitude of -19.06, SN 2007ru is comparable in brightness with SN 1998bw and lies at the brighter end of the observed SNe Ic. The ejected mass of Ni-56 is estimated to be similar to 0.4 M-circle dot. The fast rise and decline of the LC and the high expansion velocity suggest that SN 2007ru is an explosion with a high kinetic energy/ejecta mass ratio (E-K/M-ej). This adds to the diversity of SNe Ic. Although the early phase spectra are most similar to those of broad-line SN 2003jd, the [O I] line profile in the nebular spectrum of SN 2007ru shows the singly peaked profile, in contrast to the doubly peaked profile in SN 2003jd. The singly peaked profile, together with the high luminosity and the high expansion velocity, may suggest that SN 2007ru could be an aspherical explosion viewed from the polar direction. Estimated oxygen abundance 12 + log(O/H) of similar to 8.8 indicates that SN 2007ru occurred in a region with nearly solar metallicity.
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By quantifying the effects of climatic variability in the sheep grazing lands of north western and western Queensland, the key biological rates of mortality and reproduction can be predicted for sheep. These rates are essential components of a decision support package which can prove a useful management tool for producers, especially if they can easily obtain the necessary predictors. When the sub-models of the GRAZPLAN ruminant biology process model were re-parameterised from Queensland data along with an empirical equation predicting the probability of ewes mating added, the process model predicted the probability of pregnancy well (86% variation explained). Predicting mortality from GRAZPLAN was less successful but an empirical equation based on relative condition of the animal (a measure based on liveweight), pregnancy status and age explained 78% of the variation in mortalities. A crucial predictor in these models was liveweight which is not often recorded on producer properties. Empirical models based on climatic and pasture conditions estimated from the pasture production model GRASP, predicted marking and mortality rates for Mitchell grass (Astrebla sp.) pastures (81% and 63% of the variation explained). These prediction equations were tested against independent data from producer properties and the model successfully validated for Mitchell grass communities.
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In this study I consider what kind of perspective on the mind body problem is taken and can be taken by a philosophical position called non-reductive physicalism. Many positions fall under this label. The form of non-reductive physicalism which I discuss is in essential respects the position taken by Donald Davidson (1917-2003) and Georg Henrik von Wright (1916-2003). I defend their positions and discuss the unrecognized similarities between their views. Non-reductive physicalism combines two theses: (a) Everything that exists is physical; (b) Mental phenomena cannot be reduced to the states of the brain. This means that according to non-reductive physicalism the mental aspect of humans (be it a soul, mind, or spirit) is an irreducible part of the human condition. Also Davidson and von Wright claim that, in some important sense, the mental aspect of a human being does not reduce to the physical aspect, that there is a gap between these aspects that cannot be closed. I claim that their arguments for this conclusion are convincing. I also argue that whereas von Wright and Davidson give interesting arguments for the irreducibility of the mental, their physicalism is unwarranted. These philosophers do not give good reasons for believing that reality is thoroughly physical. Notwithstanding the materialistic consensus in the contemporary philosophy of mind the ontology of mind is still an uncharted territory where real breakthroughs are not to be expected until a radically new ontological position is developed. The third main claim of this work is that the problem of mental causation cannot be solved from the Davidsonian - von Wrightian perspective. The problem of mental causation is the problem of how mental phenomena like beliefs can cause physical movements of the body. As I see it, the essential point of non-reductive physicalism - the irreducibility of the mental - and the problem of mental causation are closely related. If mental phenomena do not reduce to causally effective states of the brain, then what justifies the belief that mental phenomena have causal powers? If mental causes do not reduce to physical causes, then how to tell when - or whether - the mental causes in terms of which human actions are explained are actually effective? I argue that this - how to decide when mental causes really are effective - is the real problem of mental causation. The motivation to explore and defend a non-reductive position stems from the belief that reductive physicalism leads to serious ethical problems. My claim is that Davidson's and von Wright's ultimate reason to defend a non-reductive view comes back to their belief that a reductive understanding of human nature would be a narrow and possibly harmful perspective. The final conclusion of my thesis is that von Wright's and Davidson's positions provide a starting point from which the current scientistic philosophy of mind can be critically further explored in the future.
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The study is an examination of how the distant national past has been conceived and constructed for Finland from the mid-sixteenth century to the Second World War. The author argues that the perception and need of a national 'Golden Age' has undergone several phases during this period, yet the perceived Greatness of the Ancient Finns has been of great importance for the growth and development of the fundamental concepts of Finnish nationalism. It is a question reaching deeper than simply discussing the Kalevala or the Karelianism of the 1890s. Despite early occurrences of most of the topics the image-makers could utilize for the construction of an Ancient Greatness, a truly national proto-history only became a necessity after 1809, when a new conceptual 'Finnishness' was both conceived and brought forth in reality. In this process of nation-building, ethnic myths of origin and descent provided the core of the nationalist cause - the defence of a primordial national character - and within a few decades the antiquarian issue became a standard element of the nationalist public enlightenment. The emerging, archaeologically substantiated, nationhood was more than a scholarly construction: it was a 'politically correct' form of ethnic self-imaging, continuously adapting its message to contemporary society and modern progress. Prehistoric and medieval Finnishness became even more relevant for the intellectual defence of the nation during the period of Russian administrative pressure 1890-1905. With independence the origins of Finnishness were militarized even further, although the 'hot' phase of antiquarian nationalism ended, as many considered the Finnish state reestablished after centuries of 'dependency'. Nevertheless, the distant past of tribal Finnishness and the conceived Golden Age of the Kalevala remained obligating. The decline of public archaeology is quite evident after 1918, even though the national message of the antiquarian pursuits remained present in the history culture of the public. The myths, symbols, images, and constructs of ancient Finnishness had already become embedded in society by the turn of the century, like the patalakki cap, which remains a symbol of Finnishness to this day. The method of approach is one of combining a broad spectrum of previously neglected primary sources, all related to history culture and the subtle banalization of the distant past: school books, postcards, illustrations, festive costumes, drama, satirical magazines, novels, jewellery, and calendars. Tracing the origins of the national myths to their original contexts enables a rather thorough deconstruction of the proto-historical imaginary in this Finnish case study. Considering Anthony D. Smith's idea of ancient 'ethnies' being the basis for nationalist causes, the author considers such an approach in the Finnish case totally misplaced.
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The attempt to refer meaningful reality as a whole to a unifying ultimate principle - the quest for the unity of Being - was one of the basic tendencies of Western philosophy from its beginnings in ancient Greece up to Hegel's absolute idealism. However, the different trends of contemporary philosophy tend to regard such a speculative metaphysical quest for unity as obsolete. This study addresses this contemporary situation on the basis of the work of Martin Heidegger (1889-1976). Its methodological framework is Heidegger's phenomenological and hermeneutical approach to the history of philosophy. It seeks to understand, in terms of the metaphysical quest for unity, Heidegger's contrast between the first (Greek) beginning or "onset" (Anfang) of philosophy and another onset of thinking. This other onset is a possibility inherent in the contemporary situation in which, according to Heidegger, the metaphysical tradition has developed to its utmost limits and thereby come to an end. Part I is a detailed interpretation of the surviving fragments of the Poem of Parmenides of Elea (fl. c. 500 BC), an outstanding representative of the first philosophical beginning in Heidegger's sense. It is argued that the Poem is not a simple denial of apparent plurality and difference ("mortal acceptances," doxai) in favor of an extreme monism. Parmenides' point is rather to show in what sense the different instances of Being can be reduced to an absolute level of truth or evidence (aletheia), which is the unity of Being as such (to eon). What in prephilosophical human experience is accepted as being is referred to the source of its acceptability: intelligibility as such, the simple and undifferentiated presence to thinking that ultimately excludes unpresence and otherness. Part II interprets selected key texts from different stages in Heidegger's thinking in terms of the unity of Being. It argues that one aspect of Heidegger's sustained and gradually deepening philosophical quest was to think the unity of Being as singularity, as the instantaneous, context-specific, and differential unity of a temporally meaningful situation. In Being and Time (1927) Heidegger articulates the temporal situatedness of the human awareness of meaningful presence. His later work moves on to study the situational correlation between presence and the human awareness. Heidegger's "postmetaphysical" articulation seeks to show how presence becomes meaningful precisely as situated, in an event of differentiation from a multidimensional context of unpresence. In resigning itself to this irreducibly complicated and singular character of meaningful presence, philosophy also faces its own historically situated finitude. This resignation is an essential feature of Heidegger's "other onset" of thinking.
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Mixtures of single odours were used to explore the receptor response profile across individual antennae of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae). Seven odours were tested including floral and green-leaf volatiles: phenyl acetaldehyde, benzaldehyde, b-caryophyllene, limonene, a-pinene, 1-hexanol, 3Z-hexenyl acetate. Electroantennograms of responses to paired mixtures of odours showed that there was considerable variation in receptor tuning across the receptor field between individuals. Data from some moth antennae showed no additivity, which indicated a restricted receptor profile. Results from other moth antennae to the same odour mixtures showed a range of partial additivity. This indicated that a wider array of receptor types was present in these moths, with a greater percentage of the receptors tuned exclusively to each odour. Peripheral receptor fields show variation in the spectrum of response within a population (of moths) when exposed to high doses of plant volatiles. This may be related to recorded variation in host choice within moth populations as reported by other authors.
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Line-transect distance sampling is a widely used method for estimating animal density from aerial surveys. Analysis of line-transect distance data usually relies on a requirement that the statistical distribution of distances of animal groups from the transect line is uniform. We show that this requirement is satisfied by the survey design if all other assumptions of distance sampling hold, but it can be violated by consistent survey problems such as responsive movement of the animals towards or away from the observer. We hypothesise that problems with the uniform requirement are unlikely to be encountered for immobile taxa, but might become substantial for species of high mobility. We test evidence for non-uniformity using double-observer distance data from two aerial surveys of five species with a spectrum of mobility capabilities and tendencies. No clear evidence against uniformity was found for crabeater seals or emperor penguins on the pack-ice in East Antarctica, while minor non-uniformity consistent with responsive movement up to 30 m was found for Adelie penguins. Strong evidence of either non-uniformity or a failure of the capture-recapture validating method was found for eastern grey kangaroos and red kangaroos in Queensland.
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The concept of vascular cognitive impairment (VCI) covers a wide spectrum of cognitive dysfunctions related to cerebrovascular disease. Among the pathophysiological determinants of VCI are cerebral stroke, white matter lesions and brain atrophy, which are known to be important risk factors for dementia. However, the specific mechanisms behind the brain abnormalities and cognitive decline are still poorly understood. The present study investigated the neuropsychological correlates of particular magnetic resonance imaging (MRI) findings, namely, medial temporal lobe atrophy (MTA), white matter hyperintensities (WMH), general cortical atrophy and corpus callosum (CC) atrophy in subjects with cerebrovascular disease. Furthermore, the cognitive profile of subcortical ischaemic vascular disease (SIVD) was examined. This study was conducted as part of two large multidisciplinary study projects, the Helsinki Stroke Aging Memory (SAM) Study and the multinational Leukoaraiosis and Disability (LADIS) Study. The SAM cohort consisted of 486 patients, between 55 and 85 years old, with ischaemic stroke from the Helsinki University Hospital, Helsinki, Finland. The LADIS Study included a mixed sample of subjects (n=639) with age-related WMH, between 65 and 84 years old, gathered from 11 centres around Europe. Both studies included comprehensive clinical and neuropsychological assessments and detailed brain MRI. The relationships between the MRI findings and the neuropsychological test performance were analysed by controlling for relevant confounding factors such as age, education and other coexisting brain lesions. The results revealed that in elderly patients with ischaemic stroke, moderate to severe MTA was specifically related to impairment of memory and visuospatial functions, but mild MTA had no clinical relevance. Instead, WMH were primarily associated with executive deficits and mental slowing. These deficits mediated the relationship between WMH and other, secondary cognitive deficits. Cognitive decline was best predicted by the overall degree of WMH, whereas the independent contribution of regional WMH measures was low. Executive deficits were the most prominent cognitive characteristic in SIVD. Compared to other stroke patients, the patients with SIVD also presented more severe memory deficits, which were related to MTA. The cognitive decline in SIVD occurred independently of depressive symptoms and, relative to healthy control subjects, it was substantial in severity. In stroke patients, general cortical atrophy also turned out to be a strong predictor of cognitive decline in a wide range of cognitive domains. Moreover, in elderly subjects with WMH, overall CC atrophy was related to reduction in mental speed, while anterior CC atrophy was independently associated with frontal lobe-mediated executive functions and attention. The present study provides cross-sectional evidence for the involvement of WMH, MTA, general cortical atrophy and CC atrophy in VCI. The results suggest that there are multifaceted pathophysiological mechanisms behind VCI in the elderly, including both vascular ischaemic lesions and neurodegenerative changes. The different pathological changes are highly interrelated processes and together they may produce cumulative effects on cognitive decline.
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Content delivery networks (CDNs) are an essential component of modern website infrastructures: edge servers located closer to users cache content, increasing robustness and capacity while decreasing latency. However, this situation becomes complicated for HTTPS content that is to be delivered using the Transport Layer Security (TLS) protocol: the edge server must be able to carry out TLS handshakes for the cached domain. Most commercial CDNs require that the domain owner give their certificate's private key to the CDN's edge server or abandon caching of HTTPS content entirely. We examine the security and performance of a recently commercialized delegation technique in which the domain owner retains possession of their private key and splits the TLS state machine geographically with the edge server using a private key proxy service. This allows the domain owner to limit the amount of trust given to the edge server while maintaining the benefits of CDN caching. On the performance front, we find that latency is slightly worse compared to the insecure approach, but still significantly better than the domain owner serving the content directly. On the security front, we enumerate the security goals for TLS handshake proxying and identify a subtle difference between the security of RSA key transport and signed-Diffie--Hellman in TLS handshake proxying; we also discuss timing side channel resistance of the key server and the effect of TLS session resumption.
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Knowledge of the molecular mechanisms involved in ionophore-mediated cation transport would be valuable for under-standing many essential functions of biological membranes1−3. Cations are transported in several stages, such as formation of the ionophore−cation complex, diffusion across the cell membrane and subsequent release of the cation. Several conformational rearrangements are involved in this process, and so a detailed understanding of all the conformational possibilities of the ionophore seems to be essential for elucidating the molecular mechanism of ion transport. We are carrying out spectroscopic and crystallographic studies to explore the possible conformational stages of ionophores by complexing them, in different solvents, with cations of various sizes and charges. We report here a novel conformation of the ionophore valinomycin in its barium complex. It can be described as an extended depsipeptide chain, without internal hydrogen bonds, wound in the form of an ellipse with the two barium ions located at the foci.
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The modern student represents a change from the traditional learner. More than ever before, additional resources are available online and yet personalised learning and peer-assistance programs are becoming an essential part of tertiary education delivery. This paper presents the first stage in a user-centred design approach to the analysis of the completeness and efficacy of such a personalised, peer-based support for learning program. This approach used an iterative design methodology based on contextual interview, workshops and focus groups to develop personas representing students visiting the program. Initial uses of these developed personas have included training of new personnel as well as the evaluation of the program. Overall the use of this user-centred approach and iterative persona development methodology has yielded an invaluable resource for the design of support for learning programs across the higher education industry within Australia and beyond.