Taurek, numbers and probabilities

In his paper, “Should the Numbers Count?" John Taurek imagines that we are in a position such that we can either save a group of five people, or we can save one individual, David. We cannot save David and the five. This is because they each require a life-saving drug. However, David needs all of the drug if he is to survive, while the other five need only a fifth each.Typically, people have argued as if there was a choice to be made: either numbers matter, in which case we should save the greater number, or numbers don't matter, but rather there is moral value in giving each person an equal chance of survival, and therefore we should toss a coin. My claim is that we do not have to make a choice in this way. Rather, numbers do matter, but it doesn't follow that we should always save the greater number. And likewise, there is moral value in giving each person an equal chance of survival, but it doesn't follow that we should always toss a coin.In addition, I argue that a similar approach can be applied to situations in which we can save one person or another, but the chances of success are different

Spinal and Supraspinal Motor Control Predictors of Rate of Torque Development

During explosive movements and potentially injurious situations, the ability to rapidly generate torque is critical. Previous research has suggested that different phases of rate of torque development (RTD) are differentiately controlled. However, the extent to which supraspinal and spinal mechanisms predict RTD at different time intervals is unknown. RTD of the plantarflexors across various phases of contraction (i.e., 0–25, 0–50, 0–100, 0–150, 0–200, and 0–250 ms) was measured in 37 participants. The following predictor variables were also measured: (a) gain of the resting soleus H-reflex recruitment curve; (b) gain of the resting homonymous post-activation depression recruitment curve; (c) gain of the GABAergic presynaptic inhibition recruitment curve; (d) the level of postsynaptic recurrent inhibition at rest; (e) level of supraspinal drive assessed by measuring V waves; and (f) the gain of the resting soleus M wave. Stepwise regression analyses were used to determine which variables significantly predicted allometrically scaled RTD. The analyses indicated that supraspinal drive was the dominant predictor of RTD across all phases. Additionally, recurrent inhibition predicted RTD in all of the time intervals except 0–150 ms. These results demonstrate the importance of supraspinal drive and recurrent inhibition to RTD

Hypothetical Northern Spawning Limit and Larval Transport of Spot

The exact northern limit of the spawning grounds of spot (Leiostomus xanthurus) has not been determined. Previous reports of spot spawning during the winter/spring in the Middle Atlantic Bight (MAB) are refuted based on the presence of low bottom-water temperatures at that time. Analyses of historic bottom isotherms in the MAB during winter/spring show that the most northerly occurrence of required 17° C bottom temperatures from December to May is on the outer continental shelf off North Carolina near the Gulf Stream. It is therefore suggested that spot recruiting to Chesapeake Bay are spawned near Cape Hatteras at the shelf break in winter. (more ...)https://scholarworks.wm.edu/vimsbooks/1145/thumbnail.jp

High sensitivity nuclear quadrupole resonance approach for detection of modulation wave motion in incommensurate systems

Journal ArticleIn contrast to conventional NMR techniques that use magnetic field gradients (MFCs) to detect the diffusion of moving atoms, we have developed a highly sensitive approach for detecting electric field gradient (EFG) fluctuations seen by stationary atoms. These EFG fluctuations were observed in the quadrupole perturbed NMR behavior of a stationary nucleus (9 3Nb) in the incommensurate insulator barium sodium niobate and are attributed to motion of the modulation wave. We observed effective diffusion constants of order 10~13 cm2/s, which are 4 orders of magnitude smaller than those currently detectable with MFG NMR

Characterizing the roGFP2-Orp1 Fluorescent Biosensor for Detecting Oxidative Stress in Mammalian Cells

Parkinson’s disease is a neurodegenerative disease involving the death of neurons in the substantia nigra and loss of the neurotransmitter, dopamine. The disease leads to progressive loss of motor control. Exact causes and mechanisms by which Parkinson’s disease proceeds are unknown, however, previous experiments determine oxidative stress in mitochondria as a factor that results in cell death. Strategies have been implemented to generate fluorescent biosensors to monitor reactive oxygen species (ROS) concentrations while simultaneously measuring the spatiotemporal distribution and correlation between the ROS, cellular function and organelle. Orp1, an enzyme found in yeast, is a sensitive oxidizing species and when coupled with fluorescent protein, roGFP2, the pair acts as a fluorescent biosensor for the ROS, hydrogen peroxide. In this study, Orp1-roGFP2 protein was expressed and purified from bacterial cell cultures and hydrogen peroxide oxidation assays were conducted to compare performance against characteristics reported in the literature.Orp1-roGFP2 is a fluorescence excitation ratiometric probe and the biosensor signal is obtained by the ratio of fluorescent intensities measured with 390 nm and 480 nm excitation. Sigmoidal kinetics were observed for biosensor oxidation by hydrogen peroxide. We also observed the Orp1-roGFP2 is highly susceptible to air oxidation. Finally the mitochondrial targeting mito-Orp1-roGFP2 gene was subcloned into a GW1 plasmid vector for mammalian expression. Future work will entail transfection of mitochondrially-targeted Orp1-roGFP2 into cultured mouse midbrain neurons to enable live-cell imaging of mitochondrial oxidative stress in cellular models of Parkinson’s disease

Balloon-borne pressure sensor performance evaluation utilizing tracking radars

The pressure sensors on balloon-borne sondes relate the sonde measurements to height above the Earth's surface through the hypsometric equation. It is crucial that sondes used to explore the vertical structure of the atmosphere do not contribute significant height errors to their measurements of atmospheric constituent concentrations and properties. A series of radiosonde flights was conducted. In most cases, each flight consisted of two sondes attached to a single balloon and each flight was tracked by a highly accurate C-band radar. For the first 19 radiosonde flights, the standard aneroid cell baroswitch assembly used was the pressure sensor. The last 26 radiosondes were equipped with a premium grade aneroid cell baroswitch assembly sensor and with a hypsometer. It is shown that both aneroid cell baroswitch sensors become increasingly inaccurate with altitude. The hypsometer radar differences are not strongly dependent upon altitude and it is found that the standard deviation of the differences at 35 km is 0.179 km

Ice sheet surface features in southwestern Greenland from satellite radio altimetry

Fourteen SEASAT and ten GEOS-3 satellite radar altimeter groundtracks across a 1 deg x 2.5 deg study area in southwestern Greenland have yielded 3,328 ice sheet surface elevations. The surface elevations derived from SEASAT were recalculated based on a waveform retracking algorithm. The elevations have been utilized to develop a surface profile, a three dimensional surface representation, and surface contours. Analysis of the elevations reveals the presence of surface terraces, some greater than 100 km in length; each terrace is at a discrete elevation. Renormalized SEASAT AGC values are shown to be correlated with the surface slope. The ice surface undulations caused frequent altimeter losses-of-lock. Future satellite radar altimeters could significantly contribute to ice sheet mapping in the next decade, particularly if they incorporate tracking systems with more frequent updates

SEASAT radar altimeter measurements over the Florida Everglades

The SEASAT satellite radar altimeter traversed the Florida Everglades on August 14, 1978. Analysis of the measurements disclosed that the altimeter pulses from 800 km above the Earth's surface penetrated the vegetation canopies to provide land and water surface elevations with accuracies better than + or - 50 cm. The altimeter waveforms required retracking over the specular Everglades surface. The altimeter-derived land elevations were correlated with large-scale topographic maps while the altimeter-derived water elevations were correlated with water gauge records of the U.S. Geological Survey. Examination of the altimeter waveforms also revealed reflections from the Everglades' surface occurring earlier than the surface reflections. These earlier surface reflections are interpreted to be from vegetation canopies, and may provide a measure of vegetation canopy heights. Future satellite radar altimeters could provide supplemental vertical control in relatively inaccessible swamp areas, could monitor water levels, and perhaps could monitor vegetation growth