Why Christians Should Not Be Kaneans about Freedom

Abstract: In this paper we argue that Robert Kane’s theory of free will cannot accommodate the possibility of a sinless individual who faces morally significant choices because a sinless agent cannot voluntarily accord value to an immoral desire, and we argue that Kane’s theory requires this. Since the Jesus of the historic Christian tradition is held to be sinless, we think Christians should reject Kane’s theory because it seems irreconcilable with historic Christian Christology. We consider two objections to our argument and argue that both fail

Detecting gravitational lensing cosmic shear from samples of several galaxies using two-dimensional spectral imaging

Studies of weak gravitational lensing by large-scale structures require the measurement of the distortions introduced to the shapes of distant galaxies at the few percent level by anisotropic light deflection along the line of sight. To detect this signal on 1-10 arcmin scales in a particular field, accurate measurements of the correlations between the shapes of order 1000-10000 galaxies are required. This large-scale averaging is required to accommodate the unknown intrinsic shapes of the background galaxies, even with careful removal of systematic effects. Here an alternative is discussed. If it is possible to measure accurately the detailed dynamical structure of the background galaxies, in particular rotating disks, then it should be possible to measure directly the cosmic shear distortion, as it generally leads to a non-self-consistent rotation curve. Narrow spectral lines and excellent two-dimensional spatial resolution are required. The ideal lines and telescope are CO rotational transitions and the Atacama Large Millimeter Array (ALMA) respectively.Comment: 12 pages, 4 figures, Expected to appear in ApJ Letters Vol. 570, 10 May 2002. Replaced with final proof version correcting minor typo

Zeolite-filled silicone rubber membranes : Part 1. Membrane preparation and pervaporation results

Amongst the alternative fuels obtained from renewable resources alcohol from fermentation may become one of the most important. The combination of fermentation with pervaporation in a membrane bioreactor offers the advantage of continuous processing. In this membrane bioreactor alcohol-selective membranes are needed. The performance of the membranes available at present is poor. Much research is being carried out on silicone rubber but the selectivity of this material for alcohol is too low. Addition to the membrane of a sorptive filler with a high selectivity towards alcohol appears to improve both selectivity and flux. Silicalite, a novel type of hydrophobic zeolite, has been used for that purpose. Results presented in this paper indicate that transport through the zeolite pores contributes to a major extent to the total transport through the membrane

Wetting criteria for the applicability of membrane distillation

Membrane distillation can only be applied on liquid mixtures which do not wet a microporous hydrophobic membrane. Solutions of inorganic material in water have such high values of surface tension (γLgreater-or-equal, slanted72x10−3 N/m) that the non-wetting condition is fulfilled for a number of hydrophobic membranes. As soon as organic solutes are present in the solution, the surface tensionγL will be lowered, and if the concentration of organic material becomes too high, wetting of the membrane will occur. By means of theoretical considerations a critical solute concentration or surface tension at which a homogeneous smooth material will be wetted (gq < 90/deg) can be calculated. For a (micro)porous membranes no such theoretical relation can be derived. Therefore, a simple experimental method is described to measure the maximum allowable concentration for a (micro)porous membrane. On the basis of these measurements, the maximum allowable concentration under process conditions can be determined

The Relationship between Structurally Different Pyrrolizidine Alkaloids and Western Flower Thrips Resistance in F2 Hybrids of Jacobaea vulgaros and Jacobaea aquatica

Segregating plant hybrids often have more ecological and molecular variability compared to parental species, and are therefore useful for studying relationships between different traits, and the adaptive significance of trait variation. Hybrid systems have been used to study the relationship between the expression of plant defense compounds and herbivore susceptibility. We conducted a western flower thrips (WFT) bioassay using a hybrid family and investigated the relationship between WFT resistance and pyrrolizidine alkaloid (PA) variation. The hybrid family consisted of two parental (Jacobaea vulgaris and Jacobaea aquatica) genotypes, two F1 genotypes, and 94 F2 hybrid lines. The J. aquatica genotype was more susceptible to thrips attack than the J. vulgaris genotype, the two F1 hybrids were as susceptible as J. aquatica, and susceptibility to WFT differed among F2 hybrid lines: 69 F2 lines were equally susceptible compared to J. aquatica, 10 F2 lines were more susceptible than J. aquatica and 15 F2 lines were as resistant as J. vulgaris or were intermediate to the two parental genotypes. Among 37 individual PAs that were derived from four structural groups (senecionine-, jacobine-, erucifoline- and otosenine-like PAs), the N-oxides of jacobine, jaconine, and jacoline were negatively correlated with feeding damage caused by WFT, and the tertiary amines of jacobine, jaconine, jacoline, and other PAs did not relate to feeding damage. Total PA concentration was negatively correlated with feeding damage. Among the four PA groups, only the total concentration of the jacobine-like PAs was negatively correlated with feeding damage. Multiple regression tests suggested that jacobine-like PAs play a greater role in WFT resistance than PAs from other structural groups. We found no evidence for synergistic effects of different PAs on WFT resistance. The relationship between PA variation and WFT feeding damage in the Jacobaea hybrids suggests a role for PAs in resistance to generalist insects

Zeolite-filled silicone rubber membranes. Experimental determination of concentration profiles

Permeant concentrations in silicalite-filled silicone rubber membranes during pervaporation of propanol/water mixtures were measured using multi-layered membranes. Experimentally determined concentration profiles show that the propanol concentration in the silicalite-filled membrane increases with increasing silicalite content. The water concentration in the membrane is low and no water is present in the silicalite particles during pervaporation.\ud The concentration profiles measured here support the observations from the resistance model that the diffusion through the membrane determines the transport rate, i.e., adsorption is a fast process

Dynamical Friction of a Circular-Orbit Perturber in a Gaseous Medium

We investigate the gravitational wake due to, and dynamical friction on, a perturber moving on a circular orbit in a uniform gaseous medium using a semi-analytic method. This work is a straightforward extension of Ostriker (1999) who studied the case of a straight-line trajectory. The circular orbit causes the bending of the wake in the background medium along the orbit, forming a long trailing tail. The wake distribution is thus asymmetric, giving rise to the drag forces in both opposite (azimuthal) and lateral (radial) directions to the motion of the perturber, although the latter does not contribute to orbital decay much. For subsonic motion, the density wake with a weak tail is simply a curved version of that in Ostriker and does not exhibit the front-back symmetry. The resulting drag force in the opposite direction is remarkably similar to the finite-time, linear-trajectory counterpart. On the other hand, a supersonic perturber is able to overtake its own wake, possibly multiple times, and develops a very pronounced tail. The supersonic tail surrounds the perturber in a trailing spiral fashion, enhancing the perturbed density at the back as well as far front of the perturber. We provide the fitting formulae for the drag forces as functions of the Mach number, whose azimuthal part is surprisingly in good agreement with the Ostriker's formula, provided Vp t=2 Rp, where Vp and Rp are the velocity and orbital radius of the perturber, respectively.Comment: 28 pages, 9 figures, accepted for publication in Astrophysical Journa

Production of Milky Way structure by the Magellanic Clouds

Previous attempts at disturbing the galactic disk by the Magellanic Clouds relied on direct tidal forcing. However, by allowing the halo to actively respond rather than remain a rigid contributor to the rotation curve, the Clouds may produce a wake in the halo which then distorts the disk. Recent work reported here suggests that the Magellanic Clouds use this mechanism to produce disk distortions sufficient to account for both the radial location, position angle and sign of the HI warp and observed anomalies in stellar kinematics towards the galactic anticenter and LSR motion.Comment: 8 pages, uuencoded compressed PostScript, no figures, html version with figures and mpeg simulations available at http://www-astro.phast.umass.edu/Preprints/martin/martin1/lmc_online.htm

Brain cholesterol in normal and pathological aging

Aberrations in cerebral cholesterol homeostasis can lead to severe neurological diseases. Recent findings strengthen the link between brain cholesterol metabolism and factors involved in synaptic plasticity, a process essential for learning and memory functions, as well as regeneration, which are affected in Alzheimer's Disease (AD). Cholesterol homeostasis within the brain is independent of that in the rest of the body and needs to be strictly regulated for optimal brain functioning. In contrast with what was initially assumed brain cholesterol homeostasis can be modulated by extra-cerebral factors. We have found that enhancement of the cholesterol-turnover in the brain by administration of the synthetic activator of liver x receptos (LXRs), T0901317, leads to restoration of memory functions in an AD mouse-model.Memory in C57Bl6NCrl mice was not further improved by the same treatment. Moreover, it was found that in contrast with cholesterol, the structurally very similar dietary derived plant sterols can enter the brain. Plant sterols may be natural activators of LXRs. Evide

Experimental results of thermally controlled superconducting switches for high frequency operation

As part of a study to develop thermally controlled switches for use in superconducting rectifiers operating at a few hertz and 1 kA, a theoretical model is presented of the thermal behavior of such a switch. The calculations are compared with experimental results of several switches having recovery times between 40 and 200 ms. A discussion is given of the maximum temperature T/sub N/ that occurs in the normal regions when the switch is in the resistive state. Once T/sub N/ is known, it is possible to predict the recovery time, activation energy, stationary dissipation and minimum propagation current. The calculated and measured results, in good agreement, show that T/sub N/ is approximately 12 K and largely independent of the thickness or material of the insulation layer. Mention is made of some problems, related to the room-temperature equipment which drives the rectifier, that so far have prevented the rectifiers from being used at their design specifications