171 research outputs found
An Atheological Apologetic
In his article, Atheological Apologetics, Scott Shalkowski argues that there is no reason to believe that the theist necessarily has the burden of proof in the debate of God\u27s existence. The strength of his argument lies in his assumptions about facts, knowledge, and justification, positive and negative existence claims, and the relevance of context in a debate. First, Shalkowski argues against Anthony Flew who states in his book, The Presumption of Atheism, that general features about knowledge claims entail the theist (who is the affirmative side of the debate) to first, introduce and defend his proposed concept of God; and, second, to provide sufficient reason for believing that this concept of his does in fact have application. Flew uses his claims about knowledge and justification to support what he calls the presumption of atheism. Secondly, Shalkowski is concerned with the distinction drawn between positive and negative existence claims. He argues that there is nothing intrinsic to positive claims that saddles them with the demand for grounds that exempts negative claims from the same demand. He rests this argument on the concept of context relativity and tries to show that in certain contexts the negative existence claims have a burden for grounds that positive ones do not, and therefore concludes that there is nothing intrinsic to positive claims that suggests that they should bear the burden of argument. I will argue first, that a presumption of atheism is justified but it is not the same presumption of negative atheism that Flew argues for. I do not take Flew\u27s presumption of atheism because Flew does not believe that context plays a role in the application of this presumption and I feel that this is a necessary ingredient to the presumption. Second, Shalkowski\u27s parallel between positive and negative existence claims is ill-founded, and his main point about context relativity ignores the relevance of what today\u27s context is and consequently damages his own position. Further, I will argue that in a scientific era, with the help of rational tools like Ockham\u27s Razor, the presumption for theism is irrational and a presumption of atheism in the traditional sense is justified
The evolution of vertically acquired HCV infection
Materials and methods All children with vertically acquired HCV infection who came to our attention and were regularly followed from the first months of life were included in this analysis. One child with double HCV and HIV infection was excluded. HCV associated clinical manifestations, viral genotype, persistence of viremia and HCV antibodies, liver biochemistry (ALT levels, bilirubin, alpha fetoprotein, coagulation parameters), liver ultrasound and other investigations to identify extrahepatic manifestations (e.g. the appearance of auto-antibodies or cryoglobulins, C3 and C4 concentrations) were evaluated
Design of the PST: A Diagnostic for 1-D Imaging of Fast Z-pinch Power Emissions RECE!PED
Fast Z-pinch technology developed on the Z machine at Sandia National Laboratones can produce up to 230 TW of thermal x-ray power for applications in inertial confinement fusion (ICF) and weapons physics experiments. During implosion, these Z-pinches develop Rayleigh-Taylor (R-T) instabilities which are very difficult to diagnose and which functionally diminish the overall pinch quality. The Power-Space-Time (PST) instrument is a newly configured diagnostic for measuring the pinch power as a function of both space and time in a Z-pinch. Placing the diagnostic at 90 degrees from the Z-pinch axis, the PST provides a new capability in collecting experimental data on R-T characteristics for making meaningful comparisons to magneto-hydrodynamic computer models. This paper is a summary of the PST diagnostic design. By slit-imaging the Z-pinch xray emissions onto a linear scintillator/fiber-optic array coupled to a streak camera system, the PST can achieve -100~m spatial resolution and -1.3 ns time resolution. Calculations indicate that a 20~m thick scintillating detection element filtered by 1000~of Al is theoretically linear in response to Plankian x-ray distributions corresponding to plasma temperatures from 40 eV to 150 eV, By calibrating this detection element to x-ray energies up to 5000 eV, the PST can provide pinch power as a function of height and time in a Z-pinch for temperatures ranging from -40 eV to -400 eV. With these system pm-meters, the PST can provide data for an experimental determination of the R-T mode number, amplitude, and growth rate during the late-time pinch implosion
Changes in the CFC inventories and formation rates of upper Labrador Sea Water, 1997-2001
Chlorofluorocarbon (component CFC-11) and hydrographic data from 1997, 1999, and 2001 are presented to track the large-scale spreading of the Upper Labrador Sea Water (ULSW) in the subpolar gyre of the North Atlantic Ocean. ULSW is CFC rich and comparatively low in salinity. It is located on top of the denser âclassicalâ Labrador Sea Water (LSW), defined in the density range ÏÎ = 27.68â27.74 kg mâ3. It follows spreading pathways similar to LSW and has entered the eastern North Atlantic. Despite data gaps, the CFC-11 inventories of ULSW in the subpolar North Atlantic (40°â65°N) could be estimated within 11%. The inventory increased from 6.0 ± 0.6 million moles in 1997 to 8.1 ± 0.6 million moles in 1999 and to 9.5 ± 0.6 million moles in 2001. CFC-11 inventory estimates were used to determine ULSW formation rates for different periods. For 1970â97, the mean formation rate resulted in 3.2â3.3 Sv (Sv ⥠106 m3 sâ1). To obtain this estimate, 5.0 million moles of CFC-11 located in 1997 in the ULSW in the subtropical/tropical Atlantic were added to the inventory of the subpolar North Atlantic. An estimate of the mean combined ULSW/LSW formation rate for the same period gave 7.6â8.9 Sv. For the years 1998â99, the ULSW formation rate solely based on the subpolar North Atlantic CFC-11 inventories yielded 6.9â9.2 Sv. At this time, the lack of classical LSW formation was almost compensated for by the strongly pronounced ULSW formation. Indications are presented that the convection area needed in 1998â99 to form this amount of ULSW exceeded the available area in the Labrador Sea. The Irminger Sea might be considered as an additional region favoring ULSW formation. In 2000â01, ULSW formation weakened to 3.3â4.7 Sv. Time series of layer thickness based on historical data indicate that there exists considerable variability of ULSW and classical LSW formation on decadal scales
Derivation of Del180 from sediment core log data\u27 Implications for millennial-scale climate change in the Labrador Sea
Sediment core logs from six sediment cores in the Labrador Sea show millennial-scale climate variability during the last glacial by recording all Heinrich events and several major Dansgaard-Oeschger cycles. The same millennial-scale climate change is documented for surface water ÎŽ18O records of Neogloboquadrina pachyderma (left coiled); hence the surface water ÎŽ18O record can be derived from sediment core logging by means of multiple linear regression, providing a paleoclimate proxy record at very high temporal resolution (70 years). For the Labrador Sea, sediment core logs contain important information about deepwater current velocities and also reflect the variable input of ice-rafted debris from different sources as inferred from grain-size analysis, the relation of density and P wave velocity, and magnetic susceptibility. For the last glacial, faster deepwater currents, which correspond to highs in sediment physical properties, occurred during iceberg discharge and lasted from several centuries to a few millennia. Those enhanced currents might have contributed to increased production of intermediate waters during times of reduced production of North Atlantic Deep Water. Hudson Strait might have acted as a major supplier of detrital carbonate only during lowered sea level (greater ice extent). During coldest atmospheric temperatures over Greenland, deepwater currents increased during iceberg discharge in the Labrador Sea, then surface water freshened shortly thereafter, while the abrupt atmospheric temperature rise happened after a larger time lag of â„ 1 kyr. The correlation implies a strong link and common forcing for atmosphere, sea surface, and deep water during the last glacial at millennial timescales but decoupling at orbital timescales
Termination of pregnancy due to Thalassemia major, Hemophilia, and Down's Syndrome: the views of Iranian physicians
<p>Abstract</p> <p>Background</p> <p>Genetic disorders due to <b>kindred </b>marriages are common medical conditions in Iran; however, the legal aspects of abortion remain controversial. This study was undertaken to determine physicians' opinions regarding the termination of pregnancy for three genetic diseases: thalassemia major, hemophilia, and Down's syndrome.</p> <p>Methods</p> <p>A questionnaire was administered to selected physicians by stratified random sampling to determine the following: age, gender, knowledge about prenatal diagnosis of diseases in high risk pregnancies, agreement with abortion, recommended gestational age for abortion, and, if opposed to abortion, the reason.</p> <p>Results</p> <p>Of 323 physicians, who participated in the study, 91.3(295), 40.6(131), and 78.6%(254) were in agreement and 8.7(28), 59.4(192), and 21.4%(69) were opposed to abortion for thalassemia major, hemophilia, and Down's syndrome, respectively. Among 289 physicians opposed to abortion in respect of each of all three conditions, the following reasons were cited: religion, 18; emotional, 10; quality of care, 23; hope to find a new treatment option in the future, 103; miscellaneous reasons, 6; and a combination of these reasons, 129. Among 680 physicians in agreement with abortion in relation to all of the diseases, 4.6%(31) were agreed with abortion in less than 12 weeks gestation, 79.2%(538) in less than 16 weeks gestation, 5.6%(38) in less than 20 weeks gestation, 2.2%(15) in less than 24 weeks gestation, and 8.4%(58) were agreed with beyond the 24 weeks of gestational age.</p> <p>Conclusion</p> <p>The majority of physicians were in agreement with abortion for thalassemia major and Down's syndrome because of the overall prognosis, but opposed to abortion for hemophilia.</p
Eddy diffusivities estimated from observations in the Labrador Sea
Eddy diffusivities in the Labrador Sea (LS) are estimated from deep eddy resolving float trajectories, moored current meter records, and satellite altimetry. A mean residence time of 248 days in the central LS is observed with several floats staying for more than 2 years. By applying a simple random walk diffusion model, the observed distribution of float residence times in the central LS could be explained by a mean eddy diffusivity of about 300 m2 sâ1. Estimates from float trajectories themselves and from moored current meter records yield significantly higher eddy diffusivities in the central LS of 950â1100 m2 sâ1. This discrepancy can be explained by an inhomogeneity of the eddy diffusivity at middepth with high/low values in the central LS/region between central LS and deep Labrador Current, which could be conjectured from the mean altimetric eddy kinetic energy (EKE) distribution. The different diffusivities explain both (1) a fast lateral homogenization of water masses in the central LS and (2) a weak exchange between central LS and boundary current. The mean Lagrangian length scale of 11.5 ± 0.7 km as estimated from deep float trajectories is only slightly larger than the mean Rossby radius of deformation (8.8 km). Largest eddy diffusivities within the central LS are associated with strong eddy drifts, rather than with large swirl velocities and associated large EKE.
between central LS and deep Labrador Current, which could be conjectured from the mean altimetric eddy kinetic energy (EKE) distribution. The different diffusivities explain both (1) a fast lateral homogenization of water masses in the central LS and (2) a weak exchange between central LS and boundary current. The mean Lagrangian length scale of 11.5 ± 0.7 km as estimated from deep float trajectories is only slightly larger than the mean Rossby radius of deformation (8.8 km). Largest eddy diffusivities within the central LS are associated with strong eddy drifts, rather than with large swirl velocities and associated large EKE
The role of salinity in the decadal variability of the North Atlantic meridional overturning circulation
Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Climate Dynamics 33 (2009): 777-793, doi:10.1007/s00382-008-0523-2.An OGCM hindcast is used to investigate the linkages between North Atlantic Ocean
salinity and circulation changes during 1963â2003. The focus is on the eastern subpolar
region consisting of the Irminger Sea and the eastern North Atlantic where a careful
assessment shows that the simulated interannual to decadal salinity changes in the upper
1500 m reproduce well those derived from the available record of hydrographic
measurements. In the model, the variability of the Atlantic meridional overturning
circulation (MOC) is primarily driven by changes in deep water formation taking place in
the Irminger Sea and, to a lesser extent, the Labrador Sea. Both are strongly influenced by
the North Atlantic Oscillation (NAO). The modeled interannual to decadal salinity changes
in the subpolar basins are mostly controlled by circulation-driven anomalies of freshwater
flux convergence, although surface salinity restoring to climatology and other boundary
fluxes each account for approximately 25% of the variance. The NAO plays an important
role: a positive NAO phase is associated with increased precipitation, reduced northward
salt transport by the wind-driven intergyre gyre, and increased southward flows of
freshwater across the Greenland-Scotland ridge. Since the NAO largely controlled deep
convection in the subpolar gyre, fresher waters are found near the sinking region during
convective events. This markedly differs from the active influence on the MOC that salinity
exerts at decadal and longer timescales in most coupled models. The intensification of the
MOC that follows a positive NAO phase by about 2 years does not lead to an increase in
the northward salt transport into the subpolar domain at low frequencies because it is
cancelled by the concomitant intensification of the subpolar gyre which shifts the subpolar
front eastward and reduces the northward salt transport by the North Atlantic Current
waters. This differs again from most coupled models, where the gyre intensification
precedes that of the MOC by several years.Support from NSF Grant
82677800 with the Woods Hole Oceanographic Institution, and (to CF) from the Institut
universitaire de France and European FP6 project DYNAMITE (contract 003903-GOCE)
and (to JD) from the NOAA Office of Hydrologic Development through a scientific
appointment administered by UCAR is gratefully acknowledged
Exceptional twentieth-century slowdown in Atlantic Ocean overturning circulation
Possible changes in Atlantic meridional overturning circulation (AMOC) provide a key source of uncertainty regarding future climate change. Maps of temperature trends over the twentieth century show a conspicuous region of cooling in the northern Atlantic. Here we present multiple lines of evidence suggesting that this cooling may be due to a reduction in the AMOC over the twentieth century and particularly after 1970. Since 1990 the AMOC seems to have partly recovered. This time evolution is consistently suggested by an AMOC index based on sea surface temperatures, by the hemispheric temperature difference, by coral-based proxies and by oceanic measurements. We discuss a possible contribution of the melting of the Greenland Ice Sheet to the slowdown. Using a multi-proxy temperature reconstruction for the AMOC index suggests that the AMOC weakness after 1975 is an unprecedented event in the past millennium (p > 0.99). Further melting of Greenland in the coming decades could contribute to further weakening of the AMOC
A novel estrogen-regulated avian apolipoprotein.
In search for yet uncharacterized proteins involved in lipid metabolism of the chicken, we have isolated a hitherto unknown protein from the serum lipoprotein fraction with a buoyant density of â€1.063 g/ml. Data obtained by protein microsequencing and molecular cloning of cDNA defined a 537 bp cDNA encoding a precursor molecule of 178 residues. As determined by SDS-PAGE, the major circulating form of the protein, which we designate apolipoprotein-VLDL-IV (Apo-IV), has an apparent Mr of approximately 17 kDa. Northern Blot analysis of different tissues of laying hens revealed Apo-IV expression mainly in the liver and small intestine, compatible with an involvement of the protein in lipoprotein metabolism. To further investigate the biology of Apo-IV, we raised an antibody against a GST-Apo-IV fusion protein, which allowed the detection of the 17-kDa protein in rooster plasma, whereas in laying hens it was detectable only in the isolated â€1.063 g/ml density lipoprotein fraction. Interestingly, estrogen treatment of roosters caused a reduction of Apo-IV in the liver and in the circulation to levels similar to those in mature hens. Furthermore, the antibody crossreacted with a 17-kDa protein in quail plasma, indicating conservation of Apo-IV in avian species. In search for mammalian counterparts of Apo-IV, alignment of the sequence of the novel chicken protein with those of different mammalian apolipoproteins revealed stretches with limited similarity to regions of ApoC-IV and possibly with ApoE from various mammalian species. These data suggest that Apo-IV is a newly identified avian apolipoprotein
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