Evaluation of ERBE scanner pointing accuracy based upon a coastline detection algorithm

Measurements from the Earth Radiation Budget Experiment (ERBE) scanning radiometers must be accurately located at the top of the Earth's atmosphere for proper interpretation of derived longwave and shortwave components of the Earth radiation field. The accuracy of the location calculations is affected by the orbit characteristics and attitude control systems of the three spacecraft, ERBS, NOAA-9, and NOAA-10. A technique was developed which makes use of the longwave scanner measurements to detect the thermal gradients at the boundaries of ocean and land masses. By analyzing many such coastline boundaries, estimates of the overall accuracy of the scanner measurement location calculations have been derived for the three satellites. The resulting measurement location errors are found to be smaller than the resolution of the radiometers, and this accuracy is well within the required location knowledge for useful science analysis of the ERBE scanner data

On the area of the symmetry orbits in T2T^2 symmetric spacetimes

We obtain a global existence result for the Einstein equations. We show that in the maximal Cauchy development of vacuum $T^2$ symmetric initial data with nonvanishing twist constant, except for the special case of flat Kasner initial data, the area of the $T^2$ group orbits takes on all positive values. This result shows that the areal time coordinate $R$ which covers these spacetimes runs from zero to infinity, with the singularity occurring at R=0.Comment: The appendix which appears in version 1 has a technical problem (the inequality appearing as the first stage of (52) is not necessarily true), and since the appendix is unnecessary for the proof of our results, we leave it out. version 2 -- clarifications added, version 3 -- reference correcte

Molecule Microscopy

Contains reports on three research projects.Joint Services Electronics Program (Contract DAAB07-71-C-0300)National Institutes of Health (Grant 5 PO1 HL14332-03)Environmental Measurements Project Laboratory grant from the Dean of Science, M.I.T

Population Density Estimates of the Montezuma Quail (Cyrtonyx montezumae) in West Texas

In Texas, USA, populations of Montezuma quail (Cyrtonyx montezumae) can be found scattered across mountain ranges in the Trans-Pecos region, including the Davis and Guadalupe, and farther east into the Edwards Plateau region. Abundance and distribution information to assist land managers in the enhancement of Montezuma quail populations is scarce due to the species’ secretive behavior and unknown abundance. We aimed to provide population density indices to fill this information gap by using a search path technique. We searched for quail in the winter of 2018–2019 in West Texas at 6 study sites: 5 private ranches and Elephant Mountain Wildlife Management Area (EMWMA). We chose survey locations based on previous quail sightings and our perception that an area contained suitable Montezuma quail habitat. We searched small watersheds using at least 2 dogs while walking along contours. The average search path length was 1.82 km (range = 0.80–4.30). We produced a hexagonal grid with a cell size of 1 ha such that no pair of coveys can be encountered on the same cell. The area associated to each search was the sum of the areas of all hexagonal cells intersected by the search path. For density index, we directly used the definition of density (birds encountered divided by area searched). Mean covey density was 1.51 ± 2.53 (± standard error) coveys/km2 (range = 0.50–4.17), although abundance data were overdispersed. The highest density estimate was for EMWMA. Mean covey size was 6.55 ± 0.61 birds/covey. These data yielded an estimate of 10.07 ± 17.45 birds/km2. As we did not account for imperfect detection, our quail density estimates are lower bounds of actual density. These quail density estimates are lower than estimates for Arizona, USA but higher than density estimates reported for the Edwards Plateau and central Mexico. A prevailing concern regarding the harvest of the Montezuma quail among some wildlife professionals and the public in Texas is the perception that Montezuma quail are scarce. Therefore, our density estimates suggest that abundance of Montezuma quail in West Texas may not be as low as perceived and that Montezuma quail populations may be appropriate for an open hunt season

Molecule Microscopy

Contains reports on summary of research and one research project.Joint Services Electronics Program (Contract DAAB07-75-C-1346)National Institutes of Health (Grant 5 S05 RR07047-10)National Institutes of Health (Grant 5 PO1 HL14322-05)National Institutes of Health (Grant 1 ROI GM22633-01

The Escape of Ionizing Photons from OB Associations in Disk Galaxies: Radiation Transfer Through Superbubbles

By solving the time-dependent radiation transfer problem of stellar radiation through evolving superbubbles within a smoothly varying HI distribution, we estimate the fraction of ionizing photons emitted by OB associations that escapes the HI disk of our Galaxy into the halo and intergalactic medium (IGM). We consider both coeval star-formation and a Gaussian star-formation history with a time spread sigma_t = 2 Myr. We consider both a uniform H I distribution and a two-phase (cloud/intercloud) model, with a negligible filling factor of hot gas. We find that the shells of the expanding superbubbles quickly trap or attenuate the ionizing flux, so that most of the escaping radiation escapes shortly after the formation of the superbubble. For the coeval star-formation history, the total fraction of Lyman Continuum photons that escape both sides of the disk in the solar vicinity is f_esc approx 0.15 +/- 0.05. For the Gaussian star formation history, f_esc approx 0.06 +/- 0.03, a value roughly a factor of two lower than the results of Dove & Shull (1994), where superbubbles were not considered. For a local production rate of ionizing photons Psi_LyC = 4.95 X 10^7 cm^{-2} s^{-1}, the flux escaping the disk is Phi_LyC approx (1.5-3.0) X 10^6 cm^{-2} s^{-1} for coeval and Gaussian star formation, comparable to the flux required to sustain the Reynolds layer.Comment: Revised version (expanded), accepted for publication by ApJ, 38 pages, 8 figures, aasms4.sty and aabib.sty files include

Composition of the Montezuma Quail’s Diet in Arizona, New Mexico, and Texas

The Montezuma quail (Cyrtonyx montezumae) is a popular game bird and an indicator species of oak-pine savannas in the northern part of its range. In Arizona and New Mexico, USA, robust populations allow for a hunting season from mid-November through mid-February. However, there is no open hunting season for this quail in Texas, USA. Data on the Montezuma quail’s diet can provide new information and improve management of the species. Our objective was to analyze the diet composition of the Montezuma quail in Arizona, New Mexico, and Texas. Specimens were collected by hunters in Arizona and New Mexico during 2016–2020 seasons and by researchers during 2018–2020 winter and spring seasons in Texas. We estimated the diet composition by macrohistological analysis of the collected quail crops. We found a high variety of food items: 178 items or morphospecies in crops (n = 175), from which 110 and 66 items were of plant and animal origin, respectively, and 2 unidentified items. We found an average (± standard error) of 5.89 ± 0.42 items/crop (range = 0–22) in Arizona (n = 107) samples, 4.15 ± 0.99 items/crop (range = 1–13) in New Mexico (n = 13), and 4.38 ± 0.40 items/crop (range = 1–12) in Texas (n = 55). Winter diet of Montezuma quail in Arizona was mainly represented by bulbs of Oxalis spp. (35.22% of dry weight), bulbs and rhizomes of Cyperus spp. (30.92%), acorns (Quercus spp.; 7.17%), and tepari beans (Phaseolus acutifolius; 6.50%). Winter diet in New Mexico consisted mainly of bulbs of Cyperus spp. (64.13%), beans of Macroptilium spp. (15.82%), and Panicum hallii grains (10.11%). In Texas, winter diet consisted mostly of rhizomes and bulbs of Cyperus spp. (28.17%), Rhynchosia senna beans (22.49%), P. hallii grains (19.54%), Allium wild onions (8.58%), and Cylindropuntia imbricata seeds (4.16%). The Montezuma quail’s spring diet in Texas consisted mainly of rhizomes and bulbs of Cyperus spp. (61.64%) and bulbs of Oxalis spp. (19.46%). The Montezuma quail diet changes in composition and proportion according to the site and season, but bulbs and rhizomes of Cyperus spp. are the predominant food items in all 3 states. This work provides novel information about the winter and spring diet of Montezuma quail in Texas. Information about Montezuma quail diet at several temporal and geographic scales will prove to be highly relevant to implement better management and conservation strategies in the northern edge of the species’ range

T Helper 1 and T Helper 2 Cells Are Pathogenic in an Antigen-specific Model of Colitis

Dysregulated T cell responses to enteric bacteria have been implicated as a common mechanism underlying pathogenesis in rodent models of colitis. However, the bacterial species and T cell specificities that induce disease have been poorly defined. We have developed a model system in which target antigen, bacterial host, and corresponding T cell specificity are defined. OVA-specific T cells from DO11.RAG-2−/− TCR transgenic mice were transferred into RAG-2−/− recipients whose intestinal tracts were colonized with OVA-expressing or control Escherichia coli. Transfer of antigen-naive DO11.RAG-2−/− T cells into recipients colonized with OVA-E. coli resulted in enhanced intestinal recruitment and cell cycling of OVA-specific T cells; however, there was no development of disease. In contrast, transfer of polarized T helper (Th) 1 and Th2 populations resulted in severe wasting and colitis in recipients colonized with OVA-expressing but not control E. coli. The histopathologic features of disease induced by Th1 and Th2 transfers were distinct, but disease severity was comparable. Induction of disease by both Th1 and Th2 transfers was dependent on bacterially associated OVA. These results establish that a single bacterially associated antigen can drive the progression of colitis mediated by both Th1 and Th2 cells and provide a new model for understanding the immunoregulatory interactions between T cells responsive to gut floral antigens

Developing Healthy Kids in Healthy Communities: Eight Evidence-based Strategies for Preventing High-risk Behaviour.

Australian youth engage in behaviour that threatens their health and wellbeing. National surveys report that about a third of young Australians have tried an illicit drug. High rates of substance use and risky sexual behaviour among young Australians suggest that effective prevention efforts based on empirical evidence need to be expanded. Church-associated organisations are an untapped resource that could be used to improve the health and welfare of young people. We describe eight evidence-based elements to consider in designing strategies to prevent high-risk behaviour in young people

Molecular Beams

Contains research objectives and reports on five research projects.Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract DAAB07-71-C-0300National Institutes of Health (Grant 5 S05 FR07046-06)Public Health Service Research Grant 1 P01 HL14322-01 from the National Heart and Lung Institute to the Harvard-M. I. T. Program in Health Services and Technolog