Preliminary design of an Earth-based debris detection system using current technology and existing installations

A simple instrument based on present-epoch technology for optical detection of orbital debris is described. The limits of detectability at various altitudes and under different operating conditions for this system are assessed. The kinds of information which can be deduced from this data are examined. Optimal systems for debris detection are discussed. Alternatives and possible improvements from new technologies are also considered

Lunar luminescence measurements

Spectra of lunar sites obtained in June 1983 have been analyzed for residual luminescence using the spectral line depth technique. The results or three sites each at three wavelengths are presented. The sites observed were Mare Crisium, Kepler, and Aristarchus. In each case, the value quoted was based not only on the strong Fraunhofer line in the spectral range covered but also on from 11 to 21 weaker lines within 80 A of the strongest feature. These data do not support previous observations. The values given do not indicate a greatly reddened spectrum, and the luminescence spectrum of the mare site is not significantly different from the two young crater sites. These observations cannot be adequately explained by thermal luminescence, theories of direct excitation are also unable to explain the strength of the flux

The Orientation of the Frog's Egg

The classical experiments of Pflüger on the segmenting frog's egg, and the important conclusions drawn by Roux from a study of the same egg, have made it very desirable to have an accurate knowledge of the relation existing between the early segmenting egg and the position of the embryo with respect to the egg. Our work in relation to the orientation of the embryo has covered the ground somewhat more extensively than that of any previous author, since we have made use of the methods employed by all of them. Our results will be considered under three headings: 1st. Normal development and location of blastopore. 2nd. Results obtained by injury to definite portions of the early embryo. 3rd. Results obtained from embryos whose development had been modified by artificial means. A word of personal explanation ought to be added. The senior author is responsible for Sections I, II, IV, and V of the present paper. The work recorded in these was done in the spring of 1893. Section II is the record of the results obtained by Umè Tsuda while a student in the Biological Laboratory of Bryn Mawr College. This work was done during the winter of 1891-2 j the account written in the spring of 1892. Only very slight alterations have been made in this portion preparatory to publication

Heredity of body color in Drosophila

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Chromosomes and Heredity

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Production of Millisecond Dips in Sco X-1 Count Rates by Dead Time Effects

Chang et al. (2006) reported millisecond duration dips in the X-ray intensity of Sco X-1 and attributed them to occultations of the source by small trans-Neptunian objects (TNOs). We have found multiple lines of evidence that these dips are not astronomical in origin, but rather the result of high-energy charged particle events in the RXTE PCA detectors. Our analysis of the RXTE data indicates that at most 10% of the observed dips in Sco X-1 could be due to occultations by TNOs, and, furthermore, we find no positive or supporting evidence for any of them being due to TNOs. We therefore believe that it is a mistake to conclude that any TNOs have been detected via occultation of Sco X-1.Comment: Submitted to ApJ; uses emulateapj.cls, 8 pages with 8 figure

Employment and Food During Coronavirus

Key Findings 1. 45% of respondents with jobs experienced some type of job disruption or loss. 19.7% had a reduction in hours or income, 9.3% had been furloughed, and 15.5% had lost their job since the coronavirus outbreak. 2. 38.5% of respondents experiencing job loss or disruption since the outbreak were classified as food insecure. 3. Respondents experiencing job disruption or loss were significantly more likely to be already implementing food purchasing or eating changes and concerned about food access compared to those who did not experience a change in employment. 4. Respondents with job disruption or loss were significantly more likely to need higher amounts of money per week to help meet their basic needs if they could no longer afford food ($100 with a reduction in hours/income,$107 furloughed, $158 with job loss, compared to$82 with no job impact)

Food Access and Security During Coronavirus: A Vermont Study

Key Findings 1. Respondents reported a 33% increase in food insecurity since the coronavirus outbreak began in Vermont (from 18% to 24%). 2. 45% of respondents with jobs experienced a job disruption or loss. 3. Respondents said the most helpful actions for meeting their food needs would be increased trust in the safety of going to stores and more food in stores. 4. Respondents worried most about food becoming unaffordable and running out of food if they were unable to go out. 5. Vermonters are using a variety of strategies to adapt: a majority of respondents are at least somewhat likely to buy foods that don\u27t go bad quickly (90%); buy different, cheaper foods (69%); and stretch the food they have by eating less (52%)