T HE total neutron cross sections of polyethylene (for hydrogen), beryllium, carbon, titanium, 1 vanadium, 1 zirconium, 1 and lead were obtained from a good geometry transmission measurement using neutrons from the University of Pittsburgh cyclotron, made available through the courtesy of Dr. A. J. Allen. Neutrons in the energy range of 13 to 15 Mev were detected by allowing the neutron beam to impinge on a polyethylene radiator and then detecting recoil protons by passing them through a proportional counter telescope 2 made up of four counters in a triple coincidence, anticoincidence arrangement. Suitable aluminum absorbers were placed between the polyethylene foil and the front counter of the telescope and between the last two counters in order to determine the lower and upper energy limits, respectively, of the sensitive range of the counter telescope. The mean neutron energy was 13.9 Mev.The samples whose neutron transmissions were measured were placed midway between the cyclotron target and the polyethylene foil of the neutron detector. The largest sample subtended a plane angle of 5° at the detector. Hence, it was necessary to correct each observed cross section for the effect of neutrons scattered elastically into the detector from the sample. This correction was calculated using the method of McMillan and Sewell. 3 Table I lists the observed cross sections, the elastic scattering corrections, and the corrected cross sections. The errors due to counting fluctuations are considered to be much greater than any others inherent in the method used, since the measured transmissions were corrected by measurement of stray neutrons scattered into the detector from the surroundings. Hence, the standard deviations listed with the corrected cross sections were calculated only on the basis of counting statistics. 4 The last column of Table I lists nuclear radii calculated from the corrected cross sections by the relation: o-< = 27ri? 2 .
A pronounced decrease of the heat capacity of VeSi in the stressed state has been observed at tempera tures below T c . In addition, a large increase of heat capacity in the stressed state is observed above about 25 °K. The effect does not appear to be directly related to the structural transformation per se since it was observed both in samples that transform and in samples that do not. The observations are consistent with a decrease in T e of about one degree in the most extensively stressed regions of the sample. So far as is known, these are the first observations of such a pronounced effect of stress on heat capacity (e.g., as much as a 20% decrease in the entropy of VeSi at 17°K). Although our present understanding of the observations is in complete, a large decrease in the density of states at the Fermi surface with stress, as proposed by Weger, appears to be involved. D URING a heat-capacity study 1 of the structural transformation in VsSi, 2 we observed a pro nounced effect of applied stress on the heat capacity of V3SL Specifically, we find a decrease in heat capacity in the stressed state at temperatures below T c (below T M in the cases where the sample undergoes a structural transformation above T c ) and an increase of heat capacity above about 25°K. The effect does not appear to be directly related to the structural transformation per se since it was observed both in samples that transform and in samples that are not believed to transform. (However, it may well be a consequence of the "softness" of the crystal with respect to shear 3 which, in turn, provides conditions leading to the struc tural transformation.) The changes in heat capacity appear to be too large to be attributed to changes in the lattice heat capacity alone and may involve a large change in the density of states at the Fermi surface as suggested by Weger 4 in connection with observations of the change in critical temperature with stress. Our observations are consistent with a decrease in T c of the order of one degree in the regions of our sample that are most highly stressed. We believe that the unusually large phonon enhancement of the density of states sug gested by Clogston 5 may be involved. A brief pre liminary report of part of our observations was given recently 6 ; so far as we know, these are the first observa tions of such a pronounced effect of stress on heat capacity (e.g., as much as a 20% decrease in the entropy of V 3 Si at 17°K).The heat-capacity observations were made using the pulse calorimeter of Morin and Maita 7 after incor-
This paper describes a research study designed to explore approaches to integrating gerontological principles within district nurse education courses. Data were collected by a descriptive survey approach. The findings of the study indicated that various approaches were used to incorporate gerontological content within the curriculum. The district nurse lecturer emerged as the crucial link in ensuring subject material related to the specialism of district nursing, and the community practice teacher was significant in enabling students to relate gerontological theory to practice-based learning. The district nurse lecturer also emerged as supportive of the multi-disciplinary nature of gerontology by encouraging shared learning activities with a range of other community health care students. Against the background of major changes in community health care delivery, district nurses are identifying areas of expertise within their role as community health care nurses. One such area of expertise lies in the care of older people within the community, who form a high percentage of patients on the district nurse's caseload. In order to ensure that district nurses are effectively prepared to meet the specialist needs of older people, district nurse education courses must incorporate gerontological content within their programmes.
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