Some n-p (Hg,Cd)Te photodiodes for 8-14 micrometer heterodyne applications

The results describing the dc and CO2 laser heterodyne characteristics of a three element photodiode array and single element and four element photodiode arrays are presented. The measured data shows that the n(+)-p configuration is capable of achieving bandwidths of 475 to 725 MHz and noise equivalent powers of 3.2 x 10 to the minus 20th power W/Hz at 77 K and 1.0 x 10 to the minus 19th power W/Hz at 145 K. The n(+)-n(-)-p photodiodes exhibited wide bandwidths (approximately 2.0 GHz) and fairly good effective heterodyne quantum efficiencies (approximately 13-30 percent at 2.0 GHz). Noise equivalent powers ranging from 1.44 x 10 to the minus 19th power W/Hz to 6.23 x 10 to the minus 20th power W/Hz were measured at 2.0 GHz

Development of a HgCdTe photomixer and impedance matched GaAs FET amplifier

A research program for the development of a 10.6 micron HgCdTe photodiode/GaAs field effect transistor amplifier package for use at cryogenic temperatures (77k). The photodiode/amplifier module achieved a noise equivalent power per unit bandwidth of 5.7 times 10 to the 20th power W/Hz at 2.0 GHz. The heterodyne sensitivity of the HgCdTe photodiode was improved by designing and building a low noise GaAs field effect transistor amplifier operating at 77K. The Johnson noise of the amplifier was reduced at 77K, and thus resulted in an increased photodiode heterodyne sensitivity

Altered nerve terminal arborization and synaptic transmission in Drosophila mutants of cell adhesion molecule fasciclin I

This work investigates the role of cell adhesion molecules in development of synaptic connections and functions through a genetic approach. Fasciclin I (Fas I) is an insect glycoprotein capable of mediating homophilic cell adhesion. It has been shown that Fas I is expressed in motor nerve axons and terminals that innervate larval body-wall muscles in Drosophila. Immunohistochemical analysis of these motor nerve terminals has revealed that nerve terminal arborization, quantified by the numbers of the nerve terminal branches and varicosities, is enhanced in the null mutant fas ITE. In contrast, the number of branches and varicosities are reduced in larvae that overexpress the Fas I molecule resulting from additional copies of the fas I transgene in P(fas I+) or the chromosome duplication in Dp(fas I) mutants. Although arborization is altered, the overall stereotypical pattern of nerve terminal innervation of the body-wall muscle fibers is preserved in all the Fas I mutants examined. The voltage-clamp analysis of excitatory junctional currents (ejcs) at the neuromuscular junction indicates that the amplitude of ejcs is reduced in fas ITE, but increased in P(fas I+) and Dp(fas I) compared to that in wild-type larvae. Further electrophysiological analysis shows that the quantal content and the evoked frequency-dependent response are affected in these mutants, indicating a defective presynaptic function in addition to the anatomic abnormality. Therefore, the cell adhesion molecule Fas I may not be essential for target recognition and synaptogenesis at the larval neuromuscular junction, but may play a role in fine-turning nerve terminal arborization and possibly in modifying, directly or indirectly, development of presynaptic functions

Infiltration rate assessment of some major soils.

End of Project ReportLandspreading of fertilisers and wastes require an evaluation of the risk of overland flow in order to minimise risks of polluting rivers and lakes. Infiltration capacity measurements offer a practical means of indexing runoff risk. The objectives of this study were to assess the spatial and temporal variability of infiltration capacity and to assess the capacity of some major Irish soils. Infiltration capacity was measured using double ring infiltrometers at freely drained (8) imperfectly drained (1) and poorly drained (1) sites. The first series was performed for one day in summer. Eight years later a second series was conducted for two days in winter and summer at the same sites. On average six replicates were required in summer and fourteen in winter to estimate the mean with 50 percent precision. Capacities were reasonably stable between years but there was a significant difference between seasons. Capacities in summer were about 3.5 times the winter values. Except on the poorly drained soil the infiltration capacity exceeded or equalled the five year return rainfall rate indicating a very small risk of overland flow in summer. In winter the capacity at three sites, including freely drained sites, were less than 2.5 mm hr-1 indicating a significant general risk in winter.European Union Structural Funding (EAGGF

Role of Gas Molecule Complexity in Environmental Electron Microscopy and Photoelectron Yield Spectroscopy

© 2016 American Chemical Society. Environmental scanning electron microscopy (ESEM) and environmental photoelectron yield spectroscopy (EPYS) enable electron imaging and spectroscopy of surfaces and interfaces in low-vacuum gaseous environments. The techniques are both appealing and limited by the range of gases that can be used to amplify electrons emitted from a sample and used to form images/spectra. However, to date only H2O and NH3 gases have been identified as highly favorable electron amplification media. Here we demonstrate that ethanol vapor (CH3CH2OH) is superior to both of these and attribute its performance to its molecular complexity and valence orbital structure. Our findings improve the present understanding of what constitutes a favorable electron amplification gas and will help expand the applicability and usefulness of the ESEM and EPYS techniques

Standards for Home Produced Foods

Every homemaker is interested in feeding her family perfectly prepared foods because it means a happier family life. Having developed a certain skill, she is anxious to test it out against that of her neighbors in community, county, state, and even national contests. There are also those who must earn money through the sale of home-produced foods. If they are to receive the highest prices they must always offer high quality products. The suggestions in this circular should prove of value to homemakers in meeting these situations

Functional effects of polymorphisms on glucocorticoid receptor modulation of human anxiogenic substance-P gene promoter activity in primary amygdala neurones

This work was funded by The BBSRC (BB/D004659/1) the Wellcome Trust (080980/Z/06/Z) and the Medical Research Council (G0701003). Colin Hay was funded by the Chief Scientist Office, Scotland. Scott Davidson was funded by a BBSRC strategic studentship (BBS/S/2005/12001). Philip Cowie was funded by the Scottish Universities Life Sciences Alliance (SULCA).Peer reviewedPublisher PD

Rat mammary carcinogenesis following neutron- or X-radiation

Female 61 to 63 - day - old Sprague-Dawley rats were exposed once to a single dose of either 0.43 - MeV neutrons or 250 - kVX - rays . For neutrons 23 rats were exposed in plastic tubes rotated around and 31 c m from a water-cooled tritium impregnated target bombarded with 2.45 - MeV protons from a V a n de Graaff generator. The mean kerma was measured at the rat location by integrating the response of a rat - sized homogeneous tissue equivalent ionization chamber of minimum mass. The ratio between absorbed dose and kerma is under investigation and is anticipated to be approximately 0.7. A compensated GM gamma-ray dosimeter indicated that the gamma - ray doses were 3.5% of the total dose. All rats were examined weekly for the presence of breast tumours and these were removed, fixed, stained and verified histologically as mammary neoplasms. At 10 months after exposure 98<7ο of the rats were a live . The neutron kerma, the per cent of rats with mammary neoplasia, and the number of rats were, respectively: 0.125 rads, 8.2°}o, 182; 0.5 rads, 9.0^0, 89; 2 rads, 20. 6,68; and 8 rads, 31.1%, 45. The X - ray results were: 30 R, 1.4% 95; 60 R, 27. l°Io, 48; and 90 R, 35.4%, 48. A 3. O^o incidence was found in 167 control rats. At 10 months after exposure the mammary neoplastic response after 8 rads of neutrons corresponds approximately to that after 60 - 90 R of X - rays . Similarly, the response after 2 rads of neutrons was intermediate between 30 and 60 R of X - rays and the response after 0 . 125 and 0.5 rads of neutrons was similar to that after 30 R of X - rays . This demonstrates that the RBE for 0.43 - MeV neutrons is much lower at high doses than at low doses. Determination of the confidence limits for the dose-RBE dependence and dose-incidence relationship will be determined as additional data are collected