From diseased wild and cultured Oreochromis niloticus in Lower Egypt, 17 Aeromonas hydrophila isolates were recovered. The mortality was between 10% and 70% in among cultured fish. The course of the disease ran in an acute manner. For cultured fish, the disease outbreaks were found mainly in winter and for the wild Nile fish, mortalities were observed in late spring and summer. Additionally wild fish were affected with ectoparasites. The LD50 values of the isolates ranged between 10(3) and 10(7). Isolates of high virulence were resistant to 1 hr boiling and to the bactericidal effect of fresh normal guinea pig serum. Moreover, they did not agglutinate in acriflavin. Only the virulent isolates could agglutinate tilapia erythrocytes. The above effects were reversed for avirulent isolates while moderately virulent isolates showed no consistency in their reactions. Tube agglutination test using O and WC antisera prepared against 6 isolates versus O ...
Use of treated effluent and duckweed biomass from a pilot-scale UASB-duckweed ponds system treating domestic sewage was evaluated in rearing Niletilapia (Oreochromis niloticus). Nutritional value of duckweed as sole feed was compared with wheat bran. Two sources of water were used for each feed trial, treated-sewage and freshwater. The experiment was conducted in parallel with a conventional settled sewage-fed fishpond. Results of growth performance demonstrated that, in case of freshwater ponds specific growth rate (SGR) of tilapia fed on fresh duckweed was significantly (p < 0.01) higher than the SGR in wheat bran fed pond. No significant difference (p > 0.05) was observed between the two feeding regimes in treated sewage fed ponds. The SGR of tilapia reared in the treated sewage-wheat bran-fed pond (TWP) was significant higher (p <0.01) than the SGR in the freshwater-wheat bran-fed pond ...
A population based survey of trachoma and blindness was conducted in a rural Nile Delta hamlet. Trachoma remains hyperendemic in this region. Active trachoma was common among preschool children; over...Full Text Available
West Nile virus (WNV) is a mosquito-borne flavivirus that infects the central nervous system of humans and other animals. In this study, we found that C3H/HeN (C3H) mice exhibited a higher morbidity...Full Text Available
We used epidemiologic data for human West Nile virus (WNV) disease in Colorado from 2003 and 2007 to determine 1) the degree to which estimates of vector-borne disease occurrence is influenced by spatial...Full Text Available
In this study we determined the composition and biogeochemistry of novel, brightly colored, white and orange microbial mats at the surface of a brine seep at the outer rim of the Chefren mud volcano....Full Text Available
The highly productive coastal Mediterranean fishery off the Nile River delta collapsed after the completion of the Aswan High Dam in 1965. But the fishery has been recovering dramatically since the...Full Text Available
It is currently unclear if the potential for West Nile virus transmission by mosquito vectors in the eastern United States is related to landscape or climate factors or both. We compared abundance of vector species between urban and suburban neighborhoods of Henrico County, VA, in relation to the following factors: temperature, precipitation, canopy cover, building footprint, and proximity to drainage infrastructure. Mosquitoes were collected throughout the 2005, 2006, and 2007 seasons and tested for West Nile virus (WNV) in pools of 10-50. Test results of mosquito pools were compared to average site abundance from 37 sites in Henrico County, VA; abundance was then examined in relation to ecological variables. Urban infrastructure was positively correlated with the abundance of Culex pipiens L./Cx. restuans, and our findings implicate combined sewer overflow systems as large contributors to Culex vector populations. No measure of urbanization ...
The Japanese medaka fish Oryzias latipes has an XX/XY sex-determination system. The Y-linked sex-determination gene DMY is a duplicate of the autosomal gene DMRT1, which encodes a DM-domain-containing...Full Text Available
The authors suggest a method of calculation of the isotherms of the spinodal and the heterogeneous equilibria in four-component systems in the framework of a unified thermodynamic model of the solution. The results of their calculations predict the existence of extended regions of immiscibility in the solid phase in the interval of temperatures usually used to obtain epitaxial layers of InAs/sub x/P/sub y/Sb/sub 1-x-y/ and AlAs/sub x/P/sub y/Sb/sub 1-x-y/.
Tilapia Nilotica were exposed to "1"4 C- carbofuran (125 MUg/1) and "1"4 C - lindane (80 MUg/1) for 96 h. Uptake period followed by 8 days depuration period. The bioconcentration factor (BCF) for carbofuran reached 32.4 at 12 h and 82 for lindane at 48 h. The amount of "1"4 C-activity found in fish treated with "1"4 C - carbofuran after the uptake period showed the following descending order: viscera > remaining parts > gills > muscles. In case of "1"4 C - lindane treated fish the recovered amount followed the order; remaining parts> viscera > gills muscles. During the depuration period, carbofuran residues taken up by fish were eliminated in 2 phases, an initial rapid phase followed by a slower gradual one. However, the rate of elimination in case of lindane was much slower especially during the first 2 days. At the end of the depuration period (8 days), the muscles (edible portion) contained 10% and 58% of "1"4 C -activity in case of carbofuran and ...
It is shown that the section of the energy surface corresponding to the longitudinal mode by the principal xy-plane for the A-15 compounds will degenerate into four points at the corners of a square at very low temperatures in the cubic phase. When the quasi-shear mode propagating along the (110) direction becomes soft, simultaneously the longitudinal mode will exhibit unusually high phonon focussing. (author).
Several researchers have investigated morphological changes on the south-eastern Mediterranean coast during the late Holocene. However, very few of these studies include quantitative data covering the last 200?years. In this study, topographical maps, nautical charts and aerial photographs are used to estimate the shoreline migrations and beach?nearshore sand balance over the last 200?years in Haifa Bay, Israel, the northernmost final depositional sink of the Nile littoral cell. The findings reflect two main periods. During the first period, between 1799 and 1928, human intervention along the bay?s coast was negligible, a significant coastal expansion of ?50 to 150?m (averages of 0.4?1.2?m/year) was measured, and sand accumulation was estimated at ?70,000?m3 annually in the beach?nearshore...
New oxomolybdenum(V) complexes MoOClL (where LH/sub 2/ = Schiff base) derived from ethanolamine and salicylaldehyde, 5-chlorosalicylaldehyde, 5-bromosalicylaldehyde, 5-nitrosalicylaldehyde, 3-ethoxysalicylaldehyde and 2-hydroxy-1-naphthaldehyde have been synthesized and characterised by elemental analyses, conductance, molecular weight, I.R. and electronic spectra and magnetic measurements. The Schiff bases behave as dibasic tridentate ONO donor ligands. The complexes are non-electrolytes and dimers. The complexes exhibit subnormal magnetic moments and are involved in antiferromagnetic exchange with S = 0 ground state. The complexes exhibit electronic spectral bands at ca. 13000 and ca. 17000 cm/sup -1/ due to the transitions dsub(xy)- > dsub(xz,yz) (/sup 2/B/sub 2/- > /sup 2/E) and dsub(xy)- > dsub(x2-y2) (/sup 2/B/sub 2/- > /sup 2/B/sub 1/), respectively. The ..nu..(Mo = O) frequency of the complexes is observed in the 900-970 ...
New oxomolybdenum(V) complexes MoOClL (where LH_2 = Schiff base) derived from ethanolamine and salicylaldehyde, 5-chlorosalicylaldehyde, 5-bromosalicylaldehyde, 5-nitrosalicylaldehyde, 3-ethoxysalicylaldehyde and 2-hydroxy-1-naphthaldehyde have been synthesized and characterised by elemental analyses, conductance, molecular weight, i.r. and electronic spectra and magnetic measurements. The Schiff bases behave as dibasic tridentate ONO donor ligands. The complexes are non-electrolytes and dimers. The complexes exhibit subnormal magnetic moments and are involved in antiferromagnetic exchange with S = 0 ground state. The complexes exhibit electronic spectral bands at ca. 13000 and ca. 17000 cm"-"1 due to the transitions dsub(xy)->dsub(xz,yz) ("2B_2->"2E) and dsub(xy)->dsub(x2-y2) ("2B_2->"2B_1), respectively. The #nu#(Mo=O) frequency of the complexes is observed in the 900-970 cm"-"1 region. On the basis of the magnetic susceptibility, ...
Experiments were conducted to confirm the isotropic spatial resolution of multislice CT with a 0.5 mm slice thickness. Isotropic spatial resolution means that the spatial resolution in the transaxial plane (X-Y plane) and that in the longitudinal direction (Z direction) are equivalent. To obtain point spread function (PSF) values in the X-Y-Z directions, three-dimensional voxel data were obtained by helical scanning of a bead phantom. The modulation transfer function (MTF) values were then obtained by three-dimensional Fourier transform of the PSF. Evaluation of the spatial resolution in the X-Y-Z directions by the MTF values showed that the spatial resolution in the Z direction does not depend on the reconstruction kernel used. It was also found that the spatial resolution in the Z direction, as compared with that in the X-Y plane, is superior with the standard kernel for the abdomen and is inferior with the high-definition kernel for the ...
Abstract Series of typical -type and pseudo--type halogen-bonded complexes BClY and BBrY and hydrogen-bonded complex BHY (B = C2H4, C2H2, and C3H6; Y = F, Cl, and Br) have been investigated using the MP2/aug-cc-pVDZ method. A striking parallelism was found in the geometries, vibrational frequencies, binding energies, and topological properties between BXY and BHY (X = Cl and Br). It has been found that the lengths of the weak bond d(X)/d(H), the frequencies of the weak bond (X)/(H), the frequency shifts (XY)/(HY), the electron densities at the bond critical point of the weak bonds c(X)/c(H), and the electron density changes c(XY)/c(HY) could be used as measures of the strengths of typical -type and pseudo--type halogen/hydrogen bonds. The typical -type and pseudo--type halogen bond and hyd...
The present invention provides a compound of the formula (Cat).sup.+.sub.z[M.sup.++(5-nitro-1H-tetrazolato-N2).sup.-.sub.x(H.sub.2- O).sub.y] where x is 3 or 4, y is 2 or 3, x+y is 6, z is 1 or 2, and M.sup.++ is selected from the group consisting of iron, cobalt, nickel, copper, zinc, chromium, and manganese, and (Cat).sup.+ is selected from the group consisting of ammonium, sodium, potassium, rubidium and cesium. A method of preparing the compound of that formula is also disclosed.
The present invention provides a compound of the formula (Cat).sup.+.sub.z[M.sup.++(5-nitro-1H-tetrazolato-N2).sup.-.sub.x(H.sub.2- O).sub.y] where x is 3 or 4, y is 2 or 3, x+y is 6, z is 1 or 2, and M.sup.++ is selected from the group consisting of iron, cobalt, nickel, copper, zinc, chromium, and manganese, and (Cat).sup.+ is selected from the group consisting of ammonium, sodium, potassium, rubidium and cesium. A method of preparing the compound of that formula is also disclosed.
Selenium (Se), zinc (Zn), magnesium (Mg), molybdenum (Mo) and vanadium (V) in 28 types of Egyptian common foodstuffs as well as drinking and irrigation water samples were determined using neutron activation analysis (NAA) and atomic absorption spectrometry (AAS). The samples were collected from 74 sites over 13 governorates as well as the Nile river, wells and tap water in the regions of the Nile Delta, Sinai, the east and west desert, and north and south Egypt. These trace elements were chosen according to international references, which show the close relationship of their deficiencies to immunity-related diseases. Calculation values of daily uptake per capita were made with the results of analysis. The results, as calculated per 100 g dry weight, showed that some Egyptian foods are rich in Se including such fish (0.94 #mu#g), sesame (0.88 #mu#g), beef meat (0.48 #mu#g), instant tea (0.42 #mu#g), mushroom (0.34 #mu#g) and eggs (0.3 #mu#g), ...
The whole equipment consists of three separate portable parts: a detector case, a microprocessor and a graphic TV monitor. Magnetic tape memory and an x-y recorder can be connected for recording the measured spectra. The analyzer contains two built-in exchangeable excitation radionuclides. Fluorescence and scattered radiation is detected using a proportional detector. The detected pulses are analyzed by a 256-channel analyzer and the results are shown on the display. The device may be used in mining laboratories, coal and ore dressing plant control rooms or in mining fields of open cast mines for quick detection of the quality of mined or dressed raw materials. (E.S.). 1 fig.
The scope of radioanalysis can be enlarged substantially by preconcentration. The minimal concentration factor required depends on the concentration to be determined, the limit of determination of the analytical technique and the maximal acceptable sample-weight. Simultaneously, the preconcentration step may cause a decontamination. In post-irradiation chemistry this is usually the crucial parameter. The present paper proposes the classification of (pre-) concentration techniques by the relation between the concentration-factor X and the decontamination-factor Y. In addition, three other criteria here are used to judge the applicability in combination with the analytical technique chosen. They stem from the minimal representative and the maximal acceptable sample-weights and the maximal acceptable dose-rate. The features of a particular combination of (pre-) concentration and analytical technique can be visualized in an X-Y graph. (author).
This paper describes the design and operating experience with a high performance control system tailored to the requirements of the SuperHILAC accelerator. A large number (20) of the latest 16-bit microcomputer boards are used in a parallel-distributed manner to get a high system bandwidth. Because of the high bandwidth, software costs and complexity are significantly reduced. The system by its very nature and design is easily upgraded and repaired. Dynamically assigned and labeled knobs, together with touch-panels, allow a flexible and efficient operator interface. An X-Y vector graphics system provides for display and labeling of real-time signals as well as general plotting functions. This control system allows attachment of a powerful auxiliary computer for scientific processing with access to accelerator parameters.
From May, 1999 to August, 2006, we performed laparoscopic diagnosis and treatment for 103 cases of impalpable testes. Among those we found 5 cases of male pseudohermaphroditism of different etiologies. Three males presented by impalpable testes with ambiguous genitalia and 2 females presented by primary amenorrhea. All of them have 46-XY normal male chromosomal pattern. In the first 3 cases, the etiology was complete gonadal dysgenesis, and 2 cases with persistent Mullerian syndrome. Timed gonadectomy for the first case and laparoscopic orchiopexy for the other 2 cases were performed. For the other 2 female cases, the etiology was complete androgen insensitivity syndrome and laparoscopic bilateral orchiectomy was performed for both of them. All the procedures were done without complications with satisfactory results. PMID:18319558
The ground state of a three-dimensional (3D) rotating trapped superfluid Fermi gas in the BCS-BEC crossover is mapped to finite N v -body vortex states by a simple ansatz. The total vortex energy is measured from the ground-state energy of the system in the absence of the vortices. The vortex state is stable since the vortex potential and rotation energies are attractive while the vortex kinetic energy and interaction between vortices are repulsive. By combining the analytical and numerical works for the minimal vortex energy, the 2D configurations of N v vortices are studied by taking into account of the finite size effects both on xy-plane and on z-direction. The calculated vortex numbers as a function of the interaction strength are appropriate to the renew experimental results by Zwier...
In the present study, human neonatal fibroblasts were isolated from a two-month-old human male. The purpose of the present investigation was the analysis of the morphology (light and transmission electron microscopy), karyotype and growth characteristics of the human neonatal fibroblast cell culture B-HNF-1. Moreover, STR typing and mitochondrial DNA amplification and sequencing was also performed. Analysis of chromosomes count showed that B-HNF-1 cell culture is diploid and has normal male karyotype 46, XY, which was stable during cultivation. The transmission electron microscopy demonstrated the ultra-structure of the B-HNF-1 cells; they have typical morphological features of proteosynthesis-active cells. Large number of fibroblasts bearing different shapes and surface characteristics ad...
The widespread use of building materials with relatively high radium concentrations may increase population exposure. A method is presented for measuring effective diffusion coefficients and exhalation rates of radon from such materials. Equations for use in the experimental determination of these values are obtained theoretically. The experimental set-up consists of a container which is hermetically sealed to a slab of the building material. Nitrogen is blown through the container and then through an ionization chamber which is connected to an electrometer and X-Y plotter, and the radon concentration is measured continuously. Exhalation rates of radon from some major building materials measured by this method will be used as reference levels. The method can also be used to determine other properties such as porosity. (author).
Individuals with male factor infertility resulting from idiopathic oligo-, astheno- or teratozoospermia are frequently offered IVF in an attempt to increase their chances of having a child. A concern remains whether these infertile males have an elevated risk of transmitting chromosomal abnormalities to their offspring. Sperm chromosomal complements from these men were assayed using the human sperm/hamster oocyte fusion system and fluorescence in situ hybridization (FISH) on sperm nuclei. For each of 5 infertile patients, 100 sperm karyotypes were analyzed and multicolour FISH analysis was performed on a minimum of 10,000 sperm nuclei for each chromosome-specific DNA probe for chromosomes 1 (pUC1.77), 12 (D12Z3), X (XC) and Y (DYZ3). As a group, the infertile patients showed increased frequencies of both numerical ({chi}{sup 2}=17.26, {proportional_to} <0.001) and total abnormalities ({chi}{sup 2}=7.78, {proportional_to} <0.01) relative to control donors when assessed by sperm ...
PLZT-7/65/35 is a ferroelectric ceramic with strong electrooptic properties and memory; it is switched through transparent electrodes when mechanically strained. Matrix addressed x-y page composers for interfacing electrical and coherent optical systems are being fabricated with PLZT. Switching voltages are 50-300 V. Optical efficiencies greater than 40% have been achieved. Strains near 2.4 x 10(-3) mm/mm permit half-wave retardation switching in 100-micro-thick plates with 80-V read-in and 190-V erase levels (60 Hz hysteresis data). A 128 x 128 element array can operate at 10(7) bits/sec with 10-microsec switching in a row at a time mode. Half-select disturbances affect contrasts. Applications in displays are also feasible. PMID:20111514
This work assesses the performance of a modified two-dimensional gamma scan system in spent fuel pin studies. The techniques for a two-dimensional gamma scan studied have been developed at the Hot Cell of Institute of Nuclear Energy Research (INER). Samples are acquired from the spent fuel pin, TPC-SP-C1, which was irradiated in a commercial reactor core (the first of its kind in Taiwan) for 2 years and then deposited in a cooling pool for 10 years. The spent fuel pin was then transferred into INER for further examination. The gamma scanning system was driven by a step motor which had an accuracy within 0.1 mm in both X-Y directions. Data obtained from this system are presented in both an isotopic distribution and contour plot. Results in this study closely correspond to those in other investigations, thereby confirming the effectiveness of this modified system. (author)
DC resistivity, dc magnetization, and specific heat of eight Sc{sub 5}Co{sub 4}Ge{sub 10}-type crystal-structure compounds R{sub 5}T{sub 4}Ge{sub 10} for R = Dy, Ho, Er, Tm, and T = Rh and Ir are presented. The resistivity, single-crystal magnetization, and specific-heat results show that in all those compounds, the magnetic moments order antiferromagnetically in the c direction at low temperature. However, in the Er and Tm compounds, the magnetizations along x-y hard directions do not show any anomalies above 2.0 K. This suggests that the ordered Er and Tm ions, which have positive quadrupole coefficients, interact with a crystal field that has an electronic potential valley along the c axis. The fitting of the hard axis magnetizations to Curie-Weiss law suggests that the resulting antiferromagnetic-like {theta} reflects the strength of the crystal-field torque on the magnetic moments rather than the strength of antiferromagnetic exchange.
DC resistivity, dc magnetization, and specific heat of eight Sc/sub 5/Co/sub 4/Ge/sub 10/-type crystal structure compounds R/sub 5/T/sub 4/Ge/sub 10/ for R = Dy, Ho, Er, Tm, and T = Rh and Ir are presented. The resistivity, single crystal magnetization, and specific heat results show that in all those compounds, the magnetic moments order antiferromagnetically in the c direction at low temperature. However, in the Er and Tm compounds, the magnetizations along x-y hard directions do not show any anomalies above 2.0 K. This suggests that the ordered Er and Tm ions, which have positive quadrupole coefficients ..cap alpha../sub j/, interact with a crystal field that has an electronic potential valley along the c axis. The fitting of the hard axis magnetizations to Curie-Weiss law suggests that the resulting antiferromagnetic-like theta reflects the strength of the crystal field torque on the magnetic moments rather than the strength of antiferromagnetic exchange. 123 ...
Contents The aim of this study was a cytogenetic analysis of stallions semen to find sex chromosome aberrations and to determine if there was an association between stallion-s age and aberration frequency for the sex chromosomes. Sperm samples were collected from 22 stallions of various age from 3 to 23-years. Multicolour FISH was performed on each sample, using probes for the sex chromosomes and EGFR gene, localized on 4p12 in domestic horse. A total of 26199 sperm cells were analysed (from 1 070 to 1 532 per animal). Among the analysed cells, there were 50.318% with X chromosome, 48.543% with Y chromosome and 1.139% with aberrant chromosomes. The frequency of aberrations was: sex chromosomes nullisomy (0.466%), XY aneuploidy (0.454%), XX disomy (0.146%), YY disomy (0.041%), diploidy (0.0...
The alloying effects on K to L shell vacancy transfer probabilities (?KL) in 3d transition metals have been carried out by X-ray fluorescence studies of various alloy compositions. K X-ray intensity ratios of Ti, Cr, Fe, Co, Ni, and Cu elements in the FexNi1?x, FexCr1?x, NixCr1?x, FexCryNi1?(x+y), TixNi1?x, TixCo1?x, and CoxCu1?x alloys have been measured following excitation by 22.69keV X-rays from a 10 mCi 109Cd radioactive point source and ?KL values for alloying elements have been determined from these ratios. The spectrum of characteristic K-X-ray photons from samples were detected with a high resolution Si(Li) detector coupled to a 4 K multichannel analyzer. The present investigation makes it possible to ...
In 2004, the Southeastern France regional council asked the regional health observatory to conduct an environmental health inventory to i) identify environmental health problems in this area; ii) examine the relations between environmental exposure to pollutants and human health; and iii) help public officials to identify priorities in this area. We collected and validated data from national, regional and local institutions, constructed environmental (levels of emissions and pollutants), health (mortality, incidence, prevalence) and behavioral indicators (e.g., complaints about odors), and compared these over time and between places when possible. For each topic, we summarized current knowledge about the links between environment and health. In southeastern France, as in other French areas, indoor air pollution, home and leisure injuries and other home-related risks are public health issues. Other topics are more significant or particular to southeastern France: transportation (air ...
Culex mosquitoes introduce the pathogens responsible for filariasis, West Nile virus, St. Louis encephalitis, and other diseases into humans. Currently, traps baited with oviposition semiochemicals play an important role in detection efforts and could provide an environmentally friendly approach to controlling their populations. The odorant binding proteins (OBPs) in the female's antenna play a crucial, if yet imperfectly understood, role in sensing oviposition cues. Here, we report the X-ray crystallography and NMR 3D structures of OBP1 for Culex quinquefasciatus (CquiOBP1) bound to an oviposition pheromone (5R,6S)-6-acetoxy-5-hexadecanolide (MOP). In both studies, CquiOBP1 had the same overall six-helix structure seen in other insect OBPs, but a detailed analysis revealed an important previously undescribed feature. There are two models for OBP-mediated signal transduction: (i) direct release of the pheromone from an internal binding pocket in a ...
Autonomous robots or remotely operated vehicles have raised high hopes in the military and industrial communities because of the potential safety improvement and gain of productivity they may provide. Waste management on nuclear sites, pallet manipulation in factories, interventions on battle-fields, etc., are actively studied. A lot of these applications require powerful four-wheel vehicles, the kinematics of which is similar to that of a car. Such vehicles have three degrees of freedom: the (x,y) positions in a plane and the orientation of the vehicle. Path planning is often understood as only changing the position of the vehicle, whereas the tasks performed by this kind of robot requires a perfect orientation of the vehicle: forklifting a pallet or docking at a loading or unloading station requires accuracy in the orientation of the vehicle. It is this requirement and the kinematic constraints of the motion mode which have led to the path-planning algorithm ...
We present a femtosecond Laser Two-Photon Polymerization (LTPP) system of large scale three-dimensional structuring for applications in tissue engineering. The direct laser writing system enables fabrication of artificial polymeric scaffolds over a large area (up to cm in lateral size) with sub-micrometer resolution which could find practical applications in biomedicine and surgery. Yb:KGW femtosecond laser oscillator (Pharos, Light Conversion. Co. Ltd.) is used as an irradiation source (75 fs, 515 nm (frequency doubled), 80 MHz). The sample is mounted on wide range linear motor driven stages having 10 nm sample positioning resolution (XY--ALS130-100, Z--ALS130-50, Aerotech, Inc.). These stages guarantee an overall travelling range of 100 mm into X and Y directions and 50 mm in Z direction and support the linear scanning speed up to 300 mm/s. By moving the sample three-dimensionally the position of laser focus in the photopolymer is changed and one is able to write ...
During Phase 2 of our study of the CIXS conceptual design we have tackled additional important issues that are unique to the ITER environment. These include the thermal control of the crystal and detector enclosures located in an environment with a 100-250 C ambient temperature, tritium containment, and the range of crystal and detector movement based on the need for spectral adjustments and the desire to make measurements of colder plasmas. In addressing these issues we have selected a ''Dewar''-type enclosure for the crystals and detectors. Applying realistic view factors for radiant heat and making allowance for conduction we have made engineering studies of this enclosure and showed that the cooling requirements can be solved and the temperature can be kept sufficiently constant without compromising the specification parameters of the CIXS. We have chosen a minimum 3 mm combined thickness of the six beryllium windows needed in a Dewar-type enclosure and showed that a single window ...
In 2009 the European Space Agency satellite mission GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) was launched. Its objectives are the precise and detailed determination of the Earth's gravity field and geoid. Its core instrument, a three axis gravitational gradiometer, measures the gravity gradient components V xx , V yy , V zz and V xz (second-order derivatives of the gravity potential V) with high precision and V xy , V yz with low precision, all in the instrument reference frame. The long wavelength gravity field is recovered from the orbit, measured by GPS (Global Positioning System). Characteristic elements of the mission are precise star tracking, a Sun-synchronous and very low (260 km) orbit, angular control by magnetic torquing and an extremely stiff and thermally stable instrument environment. GOCE is complementary to GRACE (Gravity Recovery and Climate Experiment), another satellite gravity mission, launched in 2002. While ...
It is proved that the mid-point grid, which is composed of samples obtained at ground track locations midway between crossover points (thus a subset of the full sampling), has the same resolving power as the full set; i.e., they resolve the same three-dimensional spectral space. The resolving power of the mid-point grid as derived previously by Tai (1995, 1998) is characterized by the Nyquist frequency ? c=? /T (where T is the repeat period of the exact-repeat satellite), and by (in local Cartesian coordinates) the zonal and meridional Nyquist wavenumber kc=2? /X and lc=2? /Y respectively (where X and Y are the east-west and north-south separation between adjacent parallel ground tracks). Here we re-derive this result in simplified terms. First, it is shown through the sampling theorem as demonstrated previously by Tai (1999) that even though samples of the real mid-point grid are not taken simultaneously, they resolve the same frequency range as that of a hypothetical mid-point grid, ...
Addition of the silane PPh[sub 2]CH[sub 2]CH[sub 2]SiMe[sub 2]H (chelH, 1a) to Pt(COD)[sub 2] (COD = cycloocta-1,5-diene) affords in high yield the cis-bis chelate Pt(chel)[sub 2] (2); formation of the same product from Pt(COD)(X)Y (X = Y = Me; X = Me, Y = Cl) has been shown by NMR spectroscopy ([sup 1]H, [sup 31]P, [sup 195]Pt) to proceed via prior coordination of chelH through P to afford Pt(chelH)[sub 2](X)(Y) (cis and trans isomers) and through intermediacy of PtH(chel)[sub 2]Cl (22) in which P trans to Si at Pt(IV) leads to an exceptionally low [sup 2]J(Pt-P) = 1084 Hz. Cleavage of Pt-Si bonds in 2 by HCl can be controlled to give the monochelate species Pt(chel)(chelH)Cl (7), from which chelH is displaced by PMe[sub 2]Ph, or trans-PtH(PPh[sub 2]CH[sub 2]SiMe[sub 2]Cl)[sub 2]Cl (9). Products related to 9 result from Pt-Si bond cleavage by I[sub 2] or MeI. Using the analogue PPh[sub 2]CH[sub 2]CH[sub 2]SiMe(Ph)H (1c) of 1a, the analogue Pt-[PPh[sub 2]CH[sub ...