13,131 research outputs found
The 1938 Longspur Tragedy in Northwest Iowa
On Thursday, January 6, of this year (1938), I received by mail from Mr. Weir R. Mills, of Pierson, Iowa, the bodies of twelve birds. They were all Lapland Longspurs (Calcarius lapponicus). Later a letter reported that these bodies had been picked up from the streets in the business district of Pierson on Thursday morning. This was the first intimation I had of a rather wide-spread destruction of these birds in northwestern Iowa on the night of January 5-6. It may be well to state at this time that there was a light snow fall on this night, but it amounted to less than a half inch. The effect of the snow on the birds will be discussed later
The Address of the President - The Taxonomic Unit
The retiring president is expected to follow the custom of addressing the Academy upon some subject of general interest. Fortunately, custom does not require that such an address shall embody one\u27s own research or investigation; but it may consist of a survey, or of reflections of a general nature. It so happens that certain fields in which I have been somewhat interested have brought me to a study of the problem of the taxonomic unit in biology
Methods in Teaching Ornithology
A brief outline is here presented of a course in ornithology (bird study, if you prefer) as I have tried to give it - never with complete success, however. In the first place, I have planned a course to give the student four semester hours of credit. (As a matter of fact, the undergraduate student of this day has so many requirements to satisfy, for graduation, for major and minor, for a teaching certificate, for practice teaching, or in his pre-professional schedule, that most students have difficulty in finding time for a 4-hour elective course). In many respects the second semester is the best time to offer a bird course, mainly because it includes the migration season and part of the nesting season. Good bird work can be clone in the fall and winter, but the number of possible problems is more limited, and the number of kinds of birds available for study is less. Nevertheless, there are some very good reasons for beginning bird study during the fall and winter season. The smaller number of birds reduces the possibility of confusion; and absence of foliage makes observation a little easier
Bird Records of the Past Two Winters, 1918-1920, in the Upper Missouri Valley
The area here considered includes northeastern Nebraska, northwestern Iowa, South Dakota, and southwestern Minnesota. From scattered points throughout this region specimens have been sent in to A. J. Anderson to be mounted, and it is through his courtesy that many of the records are here presented. Local records, in the vicinity of Sioux City, are made by the writer unless otherwise credited
Bird Records of Two Winters, 1920-1922, in the Upper Missouri Valley
The writer has published three papers in the Proceedings of this Academy dealing with the winter bird life in the Missouri River region during the years from 1916 to 1920. More recently Mr. Chas. J. Spiker has published a paper on the same subject dealing with the years from 1922 to 1926. The present paper is intended to bridge the gap between these two periods and to place in permanent form a few very interesting and important records of the bird life in the region dealt with
Notes on the Birds of South Dakota, with a Preliminary List for Union County
This paper is prepared for the primary purpose of publishing a few interesting or unusual records for the state of South Dakota which have been very kindly placed in my possession by Mr. A. J. Anderson, of Sioux City, Iowa. Mr. Anderson, in his professional occupation as a taxidermist, has received many specimens from a radius of two or three hundred miles, and the present paper was conceived for the purpose of placing on record such of these specimens from South Dakota (and two or three from North Dakota) as seemed worthy. At the same time it seemed that it might be worthwhile for the author to include such observations as he has, incidentally, made within that state, or has received from other observers
Bird Records During the Past Winter, 1916-1917, in Northwestern Iowa
The winter of 1916-1917 has shown a number of uncommon things concerning the avifauna of the region under consideration, of which Sioux City is the central station. The notes will be presented in the form of an annotated list of the birds found, but account will not be taken of a number of late migrating species which were seen within the limits of time hereinafter adopted, such, for example, as the Pipit, and others. Winter visitors and summer stragglers only will be listed
Late Fall and Winter Birds Records, for 1941 to 1947, in the Upper Missouri Valley
The present paper is the ninth contribution in a series of reports on the winter bird life in a section of the Upper Missouri Valley, with particular emphasis on the area contiguous to Sioux City, Iowa. The area includes parts of three state (Iowa, South Dakota, and Nebraska). The time covered by the nine reports is now thirty years. As in earlier papers the annual period covered is from November 1 to March 1-four months. But in a few cases we have included interesting records just outside of these limits. The area included is not well defined, for we have accepted records as they have come, without being restrained by an arbitrary boundary
Application of advanced technology to space automation
Automated operations in space provide the key to optimized mission design and data acquisition at minimum cost for the future. The results of this study strongly accentuate this statement and should provide further incentive for immediate development of specific automtion technology as defined herein. Essential automation technology requirements were identified for future programs. The study was undertaken to address the future role of automation in the space program, the potential benefits to be derived, and the technology efforts that should be directed toward obtaining these benefits
Tumour volume response, initial cell kill and cellular repopulation in B16 melanoma treated with cyclophosphamide and 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea.
The relationship between tumour volume response and cell kill in B16 melanoma following treatment in vivo with cyclophosphamide (CY) and 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) was investigated. Tumour volume response, expressed as growth delay, was estimated from measurements of tumour dimensions. Depression of in vitro colony-forming ability of cells from treated tumours was used as the measure of tumour cell kill. The relationship between these parameters was clearly different for the two agents studied. CY produced more growth delay (7.5 days) per decade of tumour cell kill than CCNU (2 to 3.5 days). The possibility that this was due to a technical artefact was rejected in favour of an alternative explanation that different rates of cellular repopulation in tumours treated with CY and CCNU might be responsible. Cellular repopulation was measured directly, by performing cell-survival assays at various times after treatment with doses of CY and CCNU which produced about 3 decades of cell kill. The rate of repopulation by clonogenic cells was much slower after treatment with CY than with CCNU, and this appears to account for the longer duration of the growth delay obtained with CY
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