525 research outputs found

    Philosophy of Religion: A Critical Introduction

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    For over twenty years, Beverley Clack and Brian R. Clack’s distinctive and thought-provoking introduction to the philosophy of religion has been of enormous value to students and scholars, providing an approach to the subject that is bold and refreshingly alternative. This revised and updated edition retains the accessibility which makes the book popular, while furthering its distinctive argument regarding the human dimension of religion. The central emphasis of the philosophy of religion – the concept of God, and the arguments for and against God’s existence – is reflected in thorough analyses, while alternative approaches to traditional philosophical theism are explored. The treatments of both the miraculous and immortality have been revised and expanded, and the concluding chapter updates the investigation of how philosophy of religion might be conducted in an age defined by religious terrorism. Clear, systematic and highly critical, the third edition of The Philosophy of Religion will continue to be essential reading for students and scholars of this fascinating and important subject.--Provided by publisher

    Mean shear flows generated by nonlinear resonant Alfven waves

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    In the context of resonant absorption, nonlinearity has two different manifestations. The first is the reduction in amplitude of perturbations around the resonant point (wave energy absorption). The second is the generation of mean shear flows outside the dissipative layer surrounding the resonant point. Ruderman et al. [Phys. Plasmas 4, 75 (1997)] studied both these effects at the slow resonance in isotropic plasmas. Clack et al. [Astron. Astrophys. 494}, 317 (2009)] investigated nonlinearity at the Alfven resonance, however, they did not include the generation of mean shear flow. In this present paper, we investigate the mean shear flow, analytically, and study its properties. We find that the flow generated is parallel to the magnetic surfaces and has a characteristic velocity proportional to ϵ1/2\epsilon^{1/2}, where ϵ\epsilon is the dimensionless amplitude of perturbations far away from the resonance. This is, qualitatively, similar to the flow generated at the slow resonance. The jumps in the derivatives of the parallel and perpendicular components of mean shear flow across the dissipative layer are derived. We estimate the generated mean shear flow to be of the order of 10kms−110{\rm kms}^{-1} in both the solar upper chromosphere and solar corona, however, this value strongly depends on the choice of boundary conditions. It is proposed that the generated mean shear flow can produce a Kelvin--Helmholtz instability at the dissipative layer which can create turbulent motions. This instability would be an additional effect, as a Kelvin--Helmholtz instability may already exist due to the velocity field of the resonant Alfven waves. This flow can also be superimposed onto existing large scale motions in the solar upper atmosphere.Comment: 11 page

    Nonlinear effects in resonant layers in solar and space plasmas

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    The present paper reviews recent advances in the theory of nonlinear driven magnetohydrodynamic (MHD) waves in slow and Alfven resonant layers. Simple estimations show that in the vicinity of resonant positions the amplitude of variables can grow over the threshold where linear descriptions are valid. Using the method of matched asymptotic expansions, governing equations of dynamics inside the dissipative layer and jump conditions across the dissipative layers are derived. These relations are essential when studying the efficiency of resonant absorption. Nonlinearity in dissipative layers can generate new effects, such as mean flows, which can have serious implications on the stability and efficiency of the resonance

    Comparative Carcinogenicity for Mouse-Skin of Smoke Condensates Prepared from Cigarettes Made from the Same Tobacco Cured by Two Processes

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    Bright tobacco grown in Mexico was either flue-cured and redried (FC) or air-cured and bulk-fermented (AC). Both FC and AC were made into cigarettes standardized for draw resistance. FC and AC cigarettes were smoked under similar conditions in a smoking machine (one 2-second 25 ml. puff per minute down to a 20 mm. butt length). Condensates were kept at 0-4° C. until applied to the skin of mice

    Nonlinear theory of resonant slow waves in anisotropic and dispersive plasmas

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    The solar corona is a typical example of a plasma with strongly anisotropic transport processes. The main dissipative mechanisms in the solar corona acting on slow magnetoacoustic waves are the anisotropic thermal conductivity and viscosity [Ballai et al., Phys. Plasmas 5, 252 (1998)] developed the nonlinear theory of driven slow resonant waves in such a regime. In the present paper the nonlinear behavior of driven magnetohydrodynamic waves in the slow dissipative layer in plasmas with strongly anisotropic viscosity and thermal conductivity is expanded by considering dispersive effects due to Hall currents. The nonlinear governing equation describing the dynamics of nonlinear resonant slow waves is supplemented by a term which describes nonlinear dispersion and is of the same order of magnitude as nonlinearity and dissipation. The connection formulas are found to be similar to their nondispersive counterparts

    Effects of Storage Conditions on the Morphology and Titer of Lentiviral Vectors

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    Lentiviral vectors are commonly used in laboratory experiments to stably integrate transgenes into host genomes. It has long been observed that storage of virus stocks leads to a decrease in viral titer, but the mechanisms driving this decrease have yet to be identified. To that end, lentiviral vector stocks were generated and stored as follows: room temperature for less than one hour, -80ºC for 24 hours, 4ºC for three days and 4ºC for 7 days. These stocks were subsequently evaluated with regard to their transducing ability and their morphology, specifically particle diameter. The vector that was stored at room temperature served as the control with viral morphology similar to other VSV-G pseudotyped viruses. These stocks were able to transduce ~100% of HEK 293T cells. Particles were unstable under the storage conditions tested, as evidenced by the fact that all stocks stored at -80°C and 4°C required concentration with an ultracentrifuge to generate a preparation suitable for visualization with TEM. The vector stored at -80°C for 24 hours exhibited some morphological changes, but only a slight decrease in titer. The morphology of vectors stored at 4°C for 3 and 7 days was not significantly different from the room temperature control, although titer was reduced to 60% and 30-40%, respectively. Thus, the decrease in titer observed in the lentiviral stocks generated and stored during this investigation appears to be the result of viral particle instability rather than morphological changes to individual particles

    Cancer and ageing in mice and men.

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    In an experiment involving 950 mice with a normal lifespan of 2-3 years, in laboratory conditions, regular benzpyrene application to the skin was started at 10, 25, 40 or 55 weeks of age. The incidence rate of malignant epithelial tumours among the survivors in each group increased steeply with time. This increase was associated directly with duration of exposure but, given duration, was independent of age at the start of exposure, as were the growth rates of already established tumours. In our experiment, although age per se was irrelevant, the cancer incidence rate increased approximately as a power of the duration of exposure to benzpyrene. This shows that the observed approximate power-law increase of most human adult cancer incidence rates with age could exist merely because age equals duration of exposure to background and spontaneous carcinogenic stimuli. Thus, no intrinsic effects of ageing (such as failing immunological surveillance or age related hormonal changes) whatever need to postulated to explain the vast increases in old age of the incidence rates of such human cancers. This result can greatly simplify speculation about mechanisms of carcinogenesis

    Impedance-Matching Hearing in Paleozoic Reptiles: Evidence of Advanced Sensory Perception at an Early Stage of Amniote Evolution

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    BACKGROUND: Insights into the onset of evolutionary novelties are key to the understanding of amniote origins and diversification. The possession of an impedance-matching tympanic middle ear is characteristic of all terrestrial vertebrates with a sophisticated hearing sense and an adaptively important feature of many modern terrestrial vertebrates. Whereas tympanic ears seem to have evolved multiple times within tetrapods, especially among crown-group members such as frogs, mammals, squamates, turtles, crocodiles, and birds, the presence of true tympanic ears has never been recorded in a Paleozoic amniote, suggesting they evolved fairly recently in amniote history. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, we performed a morphological examination and a phylogenetic analysis of poorly known parareptiles from the Middle Permian of the Mezen River Basin in Russia. We recovered a well-supported clade that is characterized by a unique cheek morphology indicative of a tympanum stretching across large parts of the temporal region to an extent not seen in other amniotes, fossil or extant, and a braincase specialized in showing modifications clearly related to an increase in auditory function, unlike the braincase of any other Paleozoic tetrapod. In addition, we estimated the ratio of the tympanum area relative to the stapedial footplate for the basalmost taxon of the clade, which, at 23:1, is in close correspondence to that of modern amniotes capable of efficient impedance-matching hearing. CONCLUSIONS/SIGNIFICANCE: Using modern amniotes as analogues, the possession of an impedance-matching middle ear in these parareptiles suggests unique ecological adaptations potentially related to living in dim-light environments. More importantly, our results demonstrate that already at an early stage of amniote diversification, and prior to the Permo-Triassic extinction event, the complexity of terrestrial vertebrate ecosystems had reached a level that proved advanced sensory perception to be of notable adaptive significance

    Acherontiscus caledoniae: the earliest heterodont and durophagous tetrapod.

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    The enigmatic tetrapod Acherontiscus caledoniae from the Pendleian stage of the Early Carboniferous shows heterodontous and durophagous teeth, representing the earliest known examples of significant adaptations in tetrapod dental morphology. Tetrapods of the Late Devonian and Early Carboniferous (Mississippian), now known in some depth, are generally conservative in their dentition and body morphologies. Their teeth are simple and uniform, being cone-like and sometimes recurved at the tip. Modifications such as keels occur for the first time in Early Carboniferous Tournaisian tetrapods. Acherontiscus, dated as from the Pendleian stage, is notable for being very small with a skull length of about 15 mm, having an elongate vertebral column and being limbless. Cladistic analysis places it close to the Early Carboniferous adelospondyls, aïstopods and colosteids and supports the hypothesis of 'lepospondyl' polyphyly. Heterodonty is associated with a varied diet in tetrapods, while durophagy suggests a diet that includes hard tissue such as chitin or shells. The mid-Carboniferous saw a significant increase in morphological innovation among tetrapods, with an expanded diversity of body forms, skull shapes and dentitions appearing for the first time.NER

    LOGIKA FUZZY UNTUK MENENTUKAN ASUPAN KALORI PADA TERAPI DIET TERHADAP PENDERITA OBESITAS

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    It takes time for a while to determine calory intake for diabetics. Computer technology has been growing rapidly, that can help human life even outside the field of computer science. One of the ways to fulfill those needs is by using fuzzy methode. Fuzzy methode has been applicated in many fields, especially in health. In diet theraphy, obesity can be prevented by restriction in food intake, called diet. Calory intake is determined manually by counting ideal weight combined with other weight. In this research, researcher use fuzzy logic to determine calory intake for patients with obesity when nutrition section still use counting ideal weight, basal needs and activity manually. Therefore, it is a need a methode that can determine calory intake in diet therapy for the sake of a new knowledge and more competitive like for Puskesmas Ambacang.Keywords : Fuzzy Logic, Mamdani Method, Calory Inta
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