1863-11-19 Assistant Surgeon Thomas Brainerd recommends discharge and treatment of Francis Pinkham for nervous diseases

https://digitalmaine.com/cw_me_4th_regiment_corr/1442/thumbnail.jp

Bluegill sunfish use high power outputs from axial muscles to generate powerful suction-feeding strikes

Suction-feeding fish rapidly expand the mouth cavity to generate high-velocity fluid flows that accelerate food into the mouth. Such fast and forceful suction expansion poses a challenge, as muscle power is limited by muscle mass and the muscles in fish heads are relatively small. The largemouth bass powers expansion with its large body muscles, with negligible power produced by the head muscles (including the sternohyoideus). However, bluegill sunfish – with powerful strikes but different morphology and feeding behavior – may use a different balance of cranial and axial musculature to power feeding and different power outputs from these muscles. We estimated the power required for suction expansion in sunfish from measurements of intraoral pressure and rate of volume change, and measured muscle length and velocity. Unlike largemouth bass, the sternohyoideus did shorten to generate power, but it and other head muscles were too small to contribute more than 5–10% of peak expansion power in sunfish. We found no evidence of catapult-style power amplification. Instead, sunfish powered suction feeding by generating high power outputs (up to 438 W kg−1) from their axial muscles. These muscles shortened across the cranial half of the body as in bass, but at faster speeds that may be nearer the optimum for power production. Sunfish were able to generate strikes of the same absolute power as bass, but with 30–40% of the axial muscle mass. Thus, species may use the body and head muscles differently to meet the requirements of suction feeding, depending on their morphology and behavior

Cold collapse and the core catastrophe

We show that a universe dominated by cold dark matter fails to reproduce the rotation curves of dark matter dominated galaxies, one of the key problems that it was designed to resolve. We perform numerical simulations of the formation of dark matter halos, each containing \gsim 10^6 particles and resolved to 0.003 times the virial radius, allowing an accurate comparison with rotation curve data. A good fit to both galactic and cluster sized halos can be achieved using the density profile rho(r) \propto [(r/r_s)^1.5(1+(r/r_s)^1.5)]^-1, where r_s is a scale radius. This profile has a steeper asymptotic slope, rho(r) \propto r^-1.5, and a sharper turnover than found by lower resolution studies. The central structure of relaxed halos that form within a hierarchical universe has a remarkably small scatter (unrelaxed halos would not host disks). We compare the results with a sample of dark matter dominated, low surface brightness (LSB) galaxies with circular velocities in the range 100-300 km/s. The rotation curves of disks within cold dark matter halos rise too steeply to match these data which require a constant mass density in the central regions. The same conclusion is reached if we compare the scale free shape of observed rotation curves with the simulation data. It is important to confirm these results using stellar rather than HI rotation curves for LSB galaxies. We test the effects of introducing a cut-off in the power spectrum that may occur in a universe dominated by warm dark matter. In this case halos form by a monolithic collapse but the final density profile hardly changes, demonstrating that the merger history does not play a role in determining the halo structure.Comment: Latex 13 pages, 4 figures. Submitted to MNRAS. High resolution colour version of figure 4 and other N-body images here: http://star-www.dur.ac.uk:80/~moore/images

Turbulent mixing, restratification, and phytoplankton growth at a submesoscale eddy

High-resolution large-eddy simulations are used to study the influence of submesoscale mixed layer instability and small-scale turbulence on phytoplankton growth in light-limited conditions. Four simulations are considered with small-scale turbulence driven by varying levels of surface cooling. Significant small-scale turbulence is seen even without surface forcing, and the downward mixing of phytoplankton is sufficient to briefly delay the developing bloom. Moderate and strong values of the constant surface heat flux (Q =− 10,−100 W/m2) are sufficient to prevent a bloom. In contrast to the critical depth hypothesis, the growth rate for phytoplankton does not appear to be controlled by the mixed layer depth. Instead, a comparison between the turbulent diffusivity above the compensation depth and a critical value predicted by the critical turbulence hypothesis closely matches the timing and magnitude of phytoplankton growth.J.R.T. was supported by a grant from the Natural Environment Research Council, award NE/J010472/1.This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1002/2016GL06910

A Large Structure of Galaxies At Redshift z~3 and its Cosmological Implications

We report the discovery of a highly significant concentration of galaxies at a redshift of =3.090. The structure is evident in a redshift histogram of photometrically selected ``Lyman break'' objects in a 9' by 18' field in which we have obtained 78 spectroscopic redshifts in the range 2.0 < z <3.4. The dimensions of the structure projected on the plane of the sky are at least 11'by 8', or 14h_{70}^{-1} by 10h_{70}^{-1} Mpc (comoving; \Omega_M=1). The concentration contains 15 galaxies and one faint (R=21.7) QSO. We consider the structure in the context of a number of cosmological models and argue that Lyman-break galaxies must be very biased tracers of mass, with an effective bias on mass scale M~10^{15}M_{\sun} ranging from b~2 for \Omega_M=0.2 to b >~6 for \Omega_M=1. In a Cold Dark Matter scenario the large bias values suggest that individual Lyman-break galaxies are associated with dark halos of mass M~10^{12} M_{\sun}, reinforcing the interpretation of these objects as the progenitors of massive galaxies at the present epoch. Preliminary results of spectroscopy in additional fields suggest that such large structures are common at z~3, with about one similar structure per survey field. The implied space density is consistent with the possibility that we are observing moderately rich clusters of galaxies in their early non-linear evolution. Finally, the spectrum of one of the QSOs discovered in our survey (z_{em} = 3.356) exhibits metal line absorption systems within the 3 redshift bins having the largest number of galaxies in field, z = 2.93, 3.09, and 3.28. These results are the first from an ongoing ``targeted'' redshift survey designed to explore the nature and distribution of star-forming galaxies in the redshift range 2.7 <~ z <~ 3.4.Comment: 24 pages including 5 ps figures, LaTeX, uses aaspp4.sty, to appear in the Astrophysical Journal. Also available at ftp://astro.caltech.edu/users/ccs/spike_preprint.ps.g

Attitudes and Performance: An Analysis of Russian Workers

This paper investigates the relationship between locus of control and performance among Russian employees, using survey data collected at 28 workplaces in 2002 in Taganrog and at 47 workplaces in 2003 in Ekaterinburg. We develop a measure that allows us to categorize the Russian employees participating in our survey as exhibiting an internal or external locus of control. We then assess the extent to which there are significant differences between “internals” and “externals” in work-related attitudes that may affect performance. In particular, we focus on (1) attitudes about outcomes associated with hard work, (2) level of job satisfaction, (3) expectation of receiving a desired reward, and (4) loyalty to and involvement with one’s organization. In each case we identify where gender and generational differences emerge. Our main objective is to determine whether Russian employees who exhibit an internal locus of control perform better than employees with an external locus of control. Our performance measures include earnings, expected promotions, and assessments of the quantity and quality of work in comparison to others at the same organization doing a similar job. Controlling for a variety of worker characteristics, we find that (1) individuals who exhibit an internal locus of control perform better, but this result is not always statistically significant; (2) even among “internals,” women earn significantly less than men and have a much lower expectation of promotion; (3) even among “internals,” experience with unemployment has a negative influence on performance.http://deepblue.lib.umich.edu/bitstream/2027.42/40144/3/wp758.pd

Direct observations of microscale turbulence and thermohaline structure in the Kuroshio Front

Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 117 (2012): C08013, doi:10.1029/2011JC007228.Direct observations of microstructure near the Kuroshio Front were conducted in August 2008 and October 2009. These show negative potential vorticity (PV) in the mixed layer south of the front, where directly measured turbulent kinetic energy dissipation rates are an order magnitude larger than predicted by wind-scaling. These elevated dissipation rates scale better with an empirical scaling, which considers local wind and Ekman buoyancy flux driven by downfront wind. Near-zero PV in the thermocline under the Kuroshio mainstream is observed at 200–300 m depth, with dissipation exceeding open ocean thermocline values by factors of 10–100. Overall, the large turbulent dissipation rates measured in the Kuroshio can be categorized into two groups, one characterized by low Richardson number along the Kuroshio Front thermocline, and the other characterized by high stratification away from the Kuroshio mainstream. The former is attributed to mixing by unbalanced frontal ageostrophic flows, and the latter is attributed to internal wave breaking. On average, both groups appear in regions of large horizontal density gradients. Observed thermohaline structure shows low salinity tongues from the surface to over 300 m depth and deep cold tongues, extending upward from 500 to 100 m depth in a narrow (20 km) zone, suggesting down and upwelling driven by geostrophic straining, which is confirmed by Quasigeostrophic-Omega equation solutions. This implies that adiabatic along isopycnal subduction and diabatic diapycnal turbulent mixing acting in tandem at the Kuroshio Front likely contribute to NPIW formation.This study is supported by Sasagawa Scientific Research grant 20-701M (the Japan Science Society), Grant- in-Aid for Young Scientists (B) 20710002, and Excellent Young Researchers Overseas Visit Program 21-7283 awarded to T. Nagai. A. Tandon would like to acknowledge support from NSFPO- 0928138 and ONR N00014-09-1-0196.2013-03-0

Rapid injection of near-inertial shear into the stratified upper ocean at an Antarctic Circumpolar Current front

The impact on the upper ocean of the passage of a short, intense storm over a Southern Ocean site, in proximity to an Antarctic Circumpolar Current front, is characterized. The storm causes a wind-induced deepening of the mixed layer and generates an inertial current. Immediate post-storm observations indicate a mixed layer extending to approximately 50 m depth. Subsequent measurements show the upper-ocean to have re-stratified, injecting near-inertial shear in stratified waters within 1 day of the storm's passage. This time scale for the development of near-inertial shear is one order of magnitude shorter than that predicted by the ?-dispersion paradigm. The observed rapid changes in upper-ocean stratification point to the existence of an as yet undocumented, efficient mechanism for injection of near-inertial shear into the stratified ocean that is in turn associated with enhanced turbulence and mixing

Horizontal density structure and restratification of the Arctic Ocean surface layer

Author Posting. © American Meteorological Society, 2012. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 42 (2012): 659–668, doi:10.1175/JPO-D-11-0125.1.Ice-tethered profiler (ITP) measurements from the Arctic Ocean’s Canada Basin indicate an ocean surface layer beneath sea ice with significant horizontal density structure on scales of hundreds of kilometers to the order 1 km submesoscale. The observed horizontal gradients in density are dynamically important in that they are associated with restratification of the surface ocean when dense water flows under light water. Such restratification is prevalent in wintertime and competes with convective mixing upon buoyancy forcing (e.g., ice growth and brine rejection) and shear-driven mixing when the ice moves relative to the ocean. Frontal structure and estimates of the balanced Richardson number point to the likelihood of dynamical restratification by isopycnal tilt and submesoscale baroclinic instability. Based on the evidence here, it is likely that submesoscale processes play an important role in setting surface-layer properties and lateral density variability in the Arctic Ocean.Funding was provided by the National Science Foundation Office of Polar Programs Arctic Sciences Section under Awards ARC-0519899, ARC-0856479, and ARC-0806306. Support was also provided by the Woods Hole Oceanographic Institution Arctic Research Initiative.2012-10-0

The Third BATSE Gamma-Ray Burst Catalog

The Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory (CGRO) has triggered on 1122 cosmic gamma-ray bursts between 1991 April 19 and 1994 September 19. These events constitute the Third BATSE (3B) burst catalog. This catalog includes the events previously reported in the 2B catalog, which covered the time interval 1991 April 19 to 1993 March 9. We present tables of the burst occurrence times, locations, peak fluxes, fluences, and durations. In general, results from previous BATSE catalogs are confirmed here with greater statistical significance. The angular distribution is consistent with isotropy. The mean galactic dipole and quadrupole moments are within 0.6 a and 0.3 a, respectively, of the values expected for isotropy. The intensity distribution is not consistent with a homogeneous distribution of burst sources, with V/V(sub max) = 0.33 +/- 0.01. The duration distribution (T(sub 90)) exhibits bimodality, with peaks at approx. 0.5 and approx. 30 s. There is no compelling evidence for burst repetition, but only weak limits can be placed on the repetition rate