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1

Structureactivity study of thiazides by magnetic resonance methods (NQR, NMR, EPR) and DFT calculations  

Microsoft Academic Search

The paper presents a comprehensive analysis of the relationship between the electronic structure of thiazides and their biological activity. The compounds of interest were studied in solid state by the resonance methods nuclear quadrupole resonance (NQR), nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) and quantum chemistry (ab inito and DFT) methods. Detailed parallel analysis of the spectroscopic parameters

J. N. Latosi?ska

2005-01-01

2

Antiferromagnetic properties of a water-vapor-inserted YBa2 Cu3 O6.5 compound studied byNMR, NQR, and muSR  

Microsoft Academic Search

We present a detailed NQR, nuclear magnetic resonance (NMR), and muSR study of the magnetic phase obtained during a topotactic chemical reaction of YBa2Cu3O6.5 high-temperature superconductor with low-pressure water vapor. Cu65 -enriched samples have been used for NQR\\/NMR studies which allows to get a good resolution in the Cu(1) NQR and Cu(2) zero field NMR (ZFNMR) spectra. It is shown

A. V. Dooglav; A. V. Egorov; I. R. Mukhamedshin; A. V. Savinkov; H. Alloul; J. Bobroff; W. A. Macfarlane; P. Mendels; G. Collin; N. Blanchard; P. G. Picard; P. J. C. King; J. Lord

2004-01-01

3

A correlation of spectroscopic parameters from different magnetic resonance spectroscopies for thiazides: a study by NQR, NMR, EPR and DFT methods  

Microsoft Academic Search

A Letter is devoted to a detailed parallel analysis of the spectroscopic parameters such as quadrupole coupling constant (NQR), chemical shift, chemical shift anisotropy, asymmetry parameter (NMR) and hyperfine coupling constant (EPR) for thiazides. The compounds were studied in solid state by the resonance (NQR, NMR and EPR) and density functional theory (DFT) methods. The spectroscopic parameters determined at room

J. N. Latosi?ska

2004-01-01

4

First-principles study of (75)As NQR in arsenic-chalcogenide compounds.  

PubMed

We present a theoretical study of the nuclear quadrupole interaction, ?(Q), of (75)As in crystalline and amorphous materials containing sulfur and selenium, and compare them with experiment. We studied a combination of hydrogen-terminated molecular clusters and periodic cells at various levels of quantum chemical theory. The results show clearly that the standard density functional theory (DFT) approximations, LDA and GGA, underestimate the nuclear quadrupole (NQR) interaction systematically, while Hartree-Fock theory overestimates it to an even greater degree. However, various levels of configuration interaction and the B3LYP hybrid exchange-correlation functional, which includes some exact exchange, give very good quantitative agreement for As bonded only to the chalcogen species. As-As bonds require highly converged basis sets. We have performed a systematic study of the effect of local distortions around an arsenic atom on ?(Q) and ?. Using a simple, semiclassical model, we have combined our total energy results with our NQR calculations to predict ?(Q) lineshapes for bond angle and bond length distortions. Our predictions for lineshape, including first and second moments, are in excellent agreement with the results of Su et al for a-As(2)S(3), a-As(2)Se(3) and a-AsSe. We offer new insight into the distortions that led to this inhomogeneous broadening. Our results show clearly that, for trivalent arsenic atoms with zero or one arsenic nearest neighbor, symmetric bond stretching is the predominant contributor to the ?(Q) linewidth. However, in the presence of two arsenic nearest neighbors, distortions of the As-As-As apex angle dominates and, in fact, leads to a much larger second moment, in agreement with experiment. PMID:21406910

Edwards, Arthur H; Taylor, P C; Campbell, Kristy A; Pineda, Andrew C

2011-01-19

5

NQR investigation and characterization of cocrystals and crystal polymorphs  

NASA Astrophysics Data System (ADS)

The application of 14N NQR to the study of cocrystals and crystal polymorphs is reviewed. In ferroelectric and antiferroelectric organic cocrystals 14N NQR is used to determine proton position in an N-H...O hydrogen bond and proton displacement below TC. In cocrystal isonicitinamide - oxalic acid (2:1) 14N NQR is used to distinguish between two polymorphs and to determine the type of the hydrogen bond (N-...H-O). The difference in the 14N NQR spectra of cocrystal formers and cocrystal is investigated in case of carbamazepine, saccharin and carbamazepine - saccharin (1:1). The experimental resolution allows an unambiguous distinction between the 14N NQR spectrum of the cocrystal and the 14N NQR spectra of the cocrystal formers. The possibility of application of NQR and double resonance for the determination of the inhomogeneity of the sample and for the study of the life time of an unstable polymorph is discussed.

Seliger, Janez; Žagar, Veselko; Asaji, Tetsuo

2013-05-01

6

Ab initio DFT study of bisphosphonate derivatives as a drug for inhibition of cancer: NMR and NQR parameters.  

PubMed

DFT computations were carried out to characterize the (17)Oand (2)H electric field gradient, EFG, in various bisphosphonate derivatives. The computations were performed at the B3LYP level with 6-311++G (d,P) standard basis set. Calculated EFG tensors were used to determine the (17)O and (2)H nuclear quadrupole coupling constant, ? and asymmetry parameter, ?. For better understanding of the bonding and electronic structure of bisphosphonates, isotropic and anisotropic NMR chemical shieldings were calculated for the (13)C, (17)O and (31)P nuclei using GIAO method for the optimized structure of intermediate bisphosphonates at B3LYP level of theory using 6-311++G (d, p) basis set. The results showed that various substituents have a strong effect on the nuclear quadrupole resonance (NQR) parameters (?, ?) of (17)O in contrast with (2)H NQR parameters. The NMR and NQR parameters were studied in order to find the correlation between electronic structure and the activity of the desired bisphosphonates. In addition, the effect of substitutions on the bisphosphonates polarity was investigated. Molecular polarity was determined via the DFT calculated dipole moment vectors and the results showed that substitution of bromine atom on the ring would increase the activity of bisphosphonates. PMID:21633790

Aghabozorg, Hussein; Sohrabi, Beheshteh; Mashkouri, Sara; Aghabozorg, Hamid Reza

2011-06-02

7

NQR study of local structures and cooling rate dependent superconductivity in La sub 2 CuO sub 4+. delta  

SciTech Connect

Structural properties of oxygen-annealed polycrystals of La{sub 2}CuO{sub 4 + {delta}} ({delta}{approximately}0.03) have been studied using {sup 139}La NQR spectroscopy. Superconducting critical temperatures were found to depend on the rate of cooling through a narrow temperature range at about 195K. Preliminary analysis of the {sup 139}La NQR spectra suggest that the oxygen-rich phase-separated region is composed of two structurally distinct phases, both of which are metallic and super-conducting. One phase has a structure closely related to the stoichiometric oxygen-poor compound. The second shows a considerable amount of apical oxygen disorder, a large shift in NQR frequency {nu}{sub Q}, and a volume fraction which increases with cooling rate. The formation of the second phase below {minus}200K is indicative of the freezing Of CuO{sub 6} octahedral tilting. Abrupt shifts in {nu}{sub Q} above {Tc} were also observed for both phases, suggestive of a local structural anomaly or charge transfer to the Cu-O plane.

Reyes, A.P.; Ahrens, E.T.; Hammel, P.C.; Heffner, R.H.; Thompson, J.D.; Canfield, P.C.; Fisk, Z. (Los Alamos National Lab., NM (United States)); Schirber, J.E. (Sandia National Labs., Albuquerque, NM (United States))

1992-01-01

8

Electron density distribution in cladribine (2-chloro-2?-deoxyadenosine) - A drug against leukemia and multiple sclerosis - Studied by multinuclear NQR spectroscopy and DFT calculations  

NASA Astrophysics Data System (ADS)

2-Chloro-2'-deoxyadenosine (Cladribine) chemotherapeutic drug has been studied experimentally in solid state by 35Cl NQR and NMR-NQR double resonance and theoretically by the Density Functional Theory. Fifteen resonance frequencies on 14N have been detected and assigned to particular nitrogen sites in the 2-CdA molecule. The effects of tautomerism, regioisomerism, conformations and molecular aggregations, related to intermolecular hydrogen bond formation, on the NQR parameters have been analysed within the DFT and AIM ( Atoms in Molecules) formalism. The properties of the whole molecule, the so-called global reactivity descriptors, have been calculated for a comparison of both syn and anti conformations of 2-CdA molecule to check the effect of crystal packing on molecular conformation.

Latosi?ska, J. N.; Latosi?ska, M.; Seliger, J.; Žagar, V.; Kazimierczuk, Z.

2009-07-01

9

Sodium and potassium salts of dichloroisocyanuric acid and their hydrates as antimicrobials agents studied by 35Cl-NQR spectroscopy and DFT calculations  

NASA Astrophysics Data System (ADS)

The electronic structure of dichloroisocyanuric acid derivatives was analysed by 35Cl-NQR spectroscopy and DFT calculations. Here we concentrate our attention on three different factors: type of metallic substituent (sodium and potassium), temperature of the sample (liquid nitrogen and room) and degree of hydration (an amount of water molecules attached to analysed compounds). In particular, all the variations in 35Cl-NQR frequencies upon hydration of salts containing sodium and potassium ions are explained as a consequence of H-bonds formation and accompanied effects of charge redistribution. Our studies can be useful in searching for the derivatives of dichloroisocyanuric acid revealing higher antimicrobial activity.

Walczak, A.; Brycki, B.; Kaczmarek, M.; Poleshchuk, O. Kh.; Ostafin, M.; Nogaj, B.

2006-06-01

10

35Cl-NQR and DFT study of electronic structure of amlodipine and felodipine vascular-selective drugs from the dihydropyridine Ca ++ antagonists group  

NASA Astrophysics Data System (ADS)

Amlodipine (AM) and felodipine (FL) have been studied in solid state by the nuclear quadrupole resonance (NQR) and density functional theory (DFT). The results have shown that NQR data do not permit a differentiation between R and S enantiomers, which is a consequence of the symmetry of the 4-aryl ring, whereas they permit a differentiation between free bases and salts. The HOMO-LUMO gap is smaller for AM than for FL, which suggests smaller energy of excitation for AM. The absolute hardness, chemical potential and electrophilicity of both AM enantiomers are lower than the corresponding values for FL enantiomers, suggesting that AM should be more reactive than FL in unimolecular reactions.

Latosi?ska, J. N.; Latosi?ska, M.; Kasprzak, J.

2008-09-01

11

Study of local magnetic fields in the oxide ?-Bi 2 O 3 by NQR and ? SR techniques  

Microsoft Academic Search

NQR and?SR investigations of the local magnetic field in?-Bi2O3 were performed. In theNQR experiments on?-Bi2O3 which is usually considered as diamagnetic, the splitting of the spectral lines revealed a local field on the bismuth nuclei. The internal magnetic field obtained by?SR significantly exceeds the dipole field from Bi nuclear magnetic moments. A possible source of the local magnetic fields is

V. N. Duginov; V. G. Grebinnik; T. N. Mamedov; V. G. Olshevsky; V. Yu. Pomjakushin; V. A. Zhukov; B. F. Kirillov; B. A. Nikolsky; V. G. Orlov; A. V. Pirogov; A. N. Ponomarev; V. A. Suetin; E. A. Kravchenko

1994-01-01

12

NQR study of local structures and cooling rate dependent superconductivity in La{sub 2}CuO{sub 4+{delta}}  

SciTech Connect

Structural properties of oxygen-annealed polycrystals of La{sub 2}CuO{sub 4 + {delta}} ({delta}{approximately}0.03) have been studied using {sup 139}La NQR spectroscopy. Superconducting critical temperatures were found to depend on the rate of cooling through a narrow temperature range at about 195K. Preliminary analysis of the {sup 139}La NQR spectra suggest that the oxygen-rich phase-separated region is composed of two structurally distinct phases, both of which are metallic and super-conducting. One phase has a structure closely related to the stoichiometric oxygen-poor compound. The second shows a considerable amount of apical oxygen disorder, a large shift in NQR frequency {nu}{sub Q}, and a volume fraction which increases with cooling rate. The formation of the second phase below {minus}200K is indicative of the freezing Of CuO{sub 6} octahedral tilting. Abrupt shifts in {nu}{sub Q} above {Tc} were also observed for both phases, suggestive of a local structural anomaly or charge transfer to the Cu-O plane.

Reyes, A.P.; Ahrens, E.T.; Hammel, P.C.; Heffner, R.H.; Thompson, J.D.; Canfield, P.C.; Fisk, Z. [Los Alamos National Lab., NM (United States); Schirber, J.E. [Sandia National Labs., Albuquerque, NM (United States)

1992-10-01

13

63,65Cu NQR study of Zn and Ni doped YBa 2Cu 3O 7  

Microsoft Academic Search

63,65Cu NQR measurements have been performed on Zn and Ni doped YBCO (YBa2Cu3?xMxO7, M?Zn or Ni, x=0.0 ? 0.09). Distinctive differences due to the nonmagnetic Zn and the magnetic Ni dopants substituted for copper are compared microscopically based on the plane and the chain 63,65Cu NQR data. Both spin-lattice and spin-spin relaxation rates decrease for Zn doped YBCO whereas they

K. S. Han; B. J. Mean; K. H. Lee; D. H. Kim; S. W. Seo; Moohee Lee; W. C. Lee; J. S. Cho

2000-01-01

14

Spatial electron density distribution of the chlorine atoms in organic and complex compounds as studied by NQR and MNDO  

Microsoft Academic Search

Quantitative correlation of the NQR frequencies and asymmetry parameters of the EFG at nuclei having spin I = 32 with the population of the indicator atom (at Npx = 2) and nonaxiality of its electron distribution has been obtained. The Npy and Npz populations of the Cl atoms in some chloro-containing organic and coordination compounds have been calculated using the

V. P. Feshin; M. Yu. Konshin

1995-01-01

15

Antiferromagnetic properties of a water-vapor-inserted YBa2 Cu3 O6.5 compound studied byNMR, NQR, and ?SR  

NASA Astrophysics Data System (ADS)

We present a detailed NQR, nuclear magnetic resonance (NMR), and ?SR study of the magnetic phase obtained during a topotactic chemical reaction of YBa2Cu3O6.5 high-temperature superconductor with low-pressure water vapor. Cu65 -enriched samples have been used for NQR/NMR studies which allows to get a good resolution in the Cu(1) NQR and Cu(2) zero field NMR (ZFNMR) spectra. It is shown that the NQR spectrum of the starting material transforms progressively under insertion of water, and almost completely disappears when about one H2O molecule is inserted per unit cell. Similarly, a Cu65 ZFNMR signal characteristic of this water inserted material appears and grows with increasing water content, which indicates that the products of the reaction are nonsuperconducting antiferromagnetic phases in which the copper electronic magnetic moments in the CuO2 bilayers are ordered. The use of Cu65 -enriched samples allowed us to reliably resolve three different copper resonances which correspond to different internal magnetic fields. The antiferromagnetic phases are also felt by proton NMR which reveals two sites with static internal fields of 150 and about 15 Gauss, respectively. ?SR studies performed on a series of samples prepared in the same way as the C65u -enriched ones reveal two muon sites with the same local fields as the proton sites, which vanish at T?400K . This indicates that muons preferentially occupy proton vacancy sites, and that the magnetic phases have similar Néel temperatures as the other bilayer undoped cuprate compounds. An analysis of the internal fields on the different spin probes suggests that they can be all assigned to a single magnetic phase at large water content in which the Cu(1) electron spins order with those of the Cu(2) . The detailed evolution of the spectra with the progressive increase of water content is shown to be compatible with a coexistence of phases during the early stages ot the reaction. It appears that even samples packed in paraffin underwent a transformation of a substantial part of the sample after 6 years storage in atmosphere. Samples packed in Stycast epoxy resin heated moderately to a temperature (200°C) undergo a reaction with epoxy decomposition products which yield the formation of the same final compound. It is clear that such effects should be considered quite seriously and avoided in experiments attempting to resolve tiny effects in these materials, such as those performed in some recent neutron scattering experiments.

Dooglav, A. V.; Egorov, A. V.; Mukhamedshin, I. R.; Savinkov, A. V.; Alloul, H.; Bobroff, J.; Macfarlane, W. A.; Mendels, P.; Collin, G.; Blanchard, N.; Picard, P. G.; King, P. J. C.; Lord, J.

2004-08-01

16

Sb NQR study of the filled skutterudite CeFe4Sb12 synthesized under high pressure  

NASA Astrophysics Data System (ADS)

We report the results of Sb nuclear quadrupole resonance (NQR) measurements on the filled skutterudite CeFe4Sb12 synthesized under high pressure (HP) and compare them with those for the sample synthesized under ambient pressure (AP) to understand the influence of the Ce-site filling fraction. The NQR spectra for the HP sample are much sharper than those for the AP sample, suggesting that the Ce filling fraction is higher. Also, the nuclear spin-lattice relaxation rate 1/ T 1 follows an exponential decrease 1/ T 1 ? exp(-?/ k B T), with the gap being ?/ k B = 270 K at temperatures above 100 K, which is larger than that for the AP sample. This result suggests that the c- f hybridization is enhanced by increasing the Ce-site filling fraction.

Magishi, Ko-ichi; Takahashi, Masahiro; Saito, Takahito; Koyama, Kuniyuki; Sugawara, Hitoshi; Saito, Takashi; Tatsuoka, Sho; Tanaka, Kenya; Sato, Hideyuki

2013-08-01

17

Electronic structure and biological activity of chosen DDT-type insecticides studied by 35Cl-NQR.  

PubMed

A correlation between the electronic structure and biological activity of chosen dichlorodiphenyltrichloroethane (DDT)-type insecticides: 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane, 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane, 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene, 2,2-bis(4-chlorophenyl)ethanoic acid and 4,4'-dichlorobenzophenone (used in agriculture) has been analysed on the basis of the (35)Cl-nuclear quadrupole resonance (NQR) spectroscopy. The (35)Cl-NQR resonance frequencies measured at 77 K have been correlated with the lethal dose (LD(50)) parameter that characterises the biological activity of these insecticides. PMID:18942076

Jadzyn, Maciej; Nogaj, Boles?aw

2009-02-01

18

NMR and NQR study of the tetrahedral frustrated quantum spin system Cu2Te2O5Br2 in its paramagnetic phase  

NASA Astrophysics Data System (ADS)

The quantum antiferromagnet Cu2Te2O5Br2 was investigated by NMR and nuclear quadrupole resonance (NQR). The T125e NMR investigation showed that there is a magnetic transition around 10.5 K at 9 T, in agreement with previous studies. From the divergence of the spin-lattice relaxation rate, we ruled out the possibility that the transition could be governed by a one-dimensional divergence of the spin-spin correlation function. The observed anisotropy of the T125e shift was shown to be due to a spin polarization of the 5s2 “E” doublet of the [TeO3E] tetrahedra, highlighting the importance of tellurium in the exchange paths. In the paramagnetic state, Br NQR and NMR measurements led to the determination of the Br hyperfine coupling and the electric field gradient tensor, and to the spin polarization of Brp orbitals. The results demonstrate the crucial role of bromine in the interaction paths between Cu spins.

Comment, Arnaud; Mayaffre, Hadrien; Mitrovi?, Vesna; Horvati?, Mladen; Berthier, Claude; Grenier, Béatrice; Millet, Patrice

2010-12-01

19

Quadrupole coupling parameters and structural aspects of crystalline and amorphous solids by NMR and NQR  

SciTech Connect

NMR and NQR techniques were combined to obtain the quadrupole coupling constant (Qcc) and asymmetry parameter ({eta}) and extract structural information for several borate, gallate, and metavanadate compounds and glasses. {sup 71}Ga and {sup 69}Ga NMR was used to study crystalline {beta}-Ga{sub 2}O{sub 3} and several gallate glasses. Quadrupole parameters were acquired for GaO{sub 6} and GaO{sub 4} units in {beta}-Ga{sub 2}O{sub 3} by the computer simulation of the NMR powder patterns. A sensitive CW NQR spectrometer was built to detect NQR resonances below 2 MHz. The spectrometer includes a modified Robinson oscillator-detector, a new bi-symmetric square wave Zeeman modulator and a computerized data acquisition system. {sup 51}V (I = 7/2) NQR resonances below 850 kHz were detected for several metavanadates at both room temperature and liquid nitrogen temperature. Two methods, Zeeman perturbed NQR powder pattern and {sup 10}B NQR, can be employed to obtain both Qcc and {eta}. With a double coil tank circuit design, pure {sup 11}B NQR was used to determine the fraction of borons in BO{sub 3} and BO{sub 4} configurations in hydrated zinc borates. {sup 11}B NMR and NQR were also used to study lead borate glasses.

Mao, Degen.

1991-01-01

20

NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts  

SciTech Connect

Our previous studies (1,2) on the zerofield NMR spectra of Cu/Co catalysts revealed that the method of preparation sensitively influences the magnetic character of the Catalyst. Catalytic studies of the earlier investigators also (3) show similar influence on the product selectivity and indicate reproducible performance is critically dependent on the control and rigor of the preparation technique. To compliment the NMR results, we have made a thorough investigation of the Hysteresis character of the Cu/Co catalysts with the metal ratio varying from 0.2 to 4.0.

Not Available

1991-12-17

21

NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts  

SciTech Connect

We have investigated a series of Cu/Co catalysts supported on Titanium Dioxide. This study has sought to examine and compare the nature and effect of the supports Chromia and Titania (Cr[sub 2]O[sub 3], and TiO[sub 2]) on the magnetic character of the Cu-Co-Cr and Cu-Co-TiO[sub 2] catalysts. The magnetization results for Cu/Co, Cu/Co/Cr, Cu/Co/TiO[sub 2] system are presented along with the magnetization data for the unsupported Cu/Co catalysts and data for supported catalysts. Pure cobalt metal has a magnetic moment of 161 emu/g. The measured emu values and the corresponding reduction percentages are given for the various catalysts investigated. The vibration sample magnetometer determines S[sub s], the saturation magnetization, emu per gram of the composite sample. The magnetization values reported are emu per gram of cobalt in the composite. As such the data normally reflects the proportion of cobalt metal that is reduced to metallic form. However, if electronic exchanges occur between cobalt and other elements in the system, the magnetic moment itself differs from the assumed value of 161 emu/g Co then the emu value observed will be the resultant due to the electronic charge density modifications in Co as well as reduction to metallic state. Our earlier NMR studies reveal such electronic structural modifications occur for Cobalt in Cu-Co and Co-TiO[sub 2] systems. The magnetization data in column 3 for Cu-Co-TiO[sub 2] systems unambiguously shows such electron exchanges do occur between cobalt and titania.

Murty, A.N.

1992-01-01

22

Application of nuclear quadrupole resonance to the study of clathrates. sup 35 Cl NQR and crystallography of clathrated CCl sub 4  

SciTech Connect

The {sup 35}Cl nuclear quadrupole resonance (NQR) spectra of CCl{sub 4} in more than 20 clathrates have been measured in the range 4-200 K. The crystal structures of CCl{sub 4}/Dianin's compound (1), CCl{sub 4}/Fe(AcAc){sub 3} (3), CCl{sub 4}/Ni(SCN){sub 2}(3-MePy){sub 4} (4), and CCl{sub 4}/Ni(exan){sub 2}(4,4{prime}-dm-2,2{prime}-bpy) (19) clathrates are also reported. Site symmetry and site multiplicity of the guest molecule in clathrates were determined by NQR spectroscopy and by x-ray crystallography. The degree of host-guest interaction was estimated from the NQR frequency shifts. The libration frequencies of the guest molecules in trigonal cavities were determined from NQR frequencies by Bayer-Kushida theory analysis.

Pang, Li; Lucken, E.A.C.; Bernardinelli, G. (Univ. de Geneve (Switzerland))

1990-11-21

23

Study of local magnetic fields in the oxide alpha-Bi2O3 by NQR and muSR techniques  

Microsoft Academic Search

NQR and muSR investigations of the local magnetic field in alpha-Bi2O3 were performed. In the NQR experiments on alpha-Bi2O3 which is usually considered as diamagnetic, the splitting of the spectral lines revealed a local field on the bismuth nuclei. The internal magnetic field obtained by muSR significantly exceeds the dipole field from Bi nuclear magnetic moments. A possible source of

V. N. Duginov; V. G. Grebinnik; T. N. Mamedov; V. G. Olshevsky; V. Yu. Pomjakushin; V. A. Zhukov; B. F. Kirillov; B. A. Nikolsky; V. G. Orlov; A. V. Pirogov; A. N. Ponomarev; V. A. Suetin; E. A. Kravchenko

1994-01-01

24

Quadrupole Coupling Parameters and Structural Aspects of Crystalline and Amorphous Solids by NMR and Nqr.  

NASA Astrophysics Data System (ADS)

Nuclear quadrupole interaction is very sensitive to the local electron distribution and chemical bondings. NMR and NQR techniques have been combined to obtain the quadrupole coupling constant ({Qcc}) and asymmetry parameter (eta) and extract structural information for several borate, gallate, and metavanadate compounds and glasses. ^{71}Ga and ^{69}Ga NMR has been used to study crystalline beta-Ga _2O_3 and several gallate glasses. Quadrupole parameters were acquired for GaO_6 and GaO_4 units in beta-Ga_2 O_3 by the computer simulation of the NMR powder patterns. A sensitive CW NQR spectrometer was built to detect NQR resonances below 2 MHz. The spectrometer includes a modified Robinson oscillator-detector, a new bi-symmetric square wave Zeeman modulator and a computerized data acquisition system. ^{51}V (I = 7/2) NQR resonances below 850 kHz have been detected for several metavanadates at both room temperature and liquid nitrogen temperature. Quadrupole parameters thus obtained are an order of magnitude more accurate than values obtained by previous NMR studies. For a spin 3/2 nucleus, the pure NQR frequency {Q_{cc}over 2}sqrt{1+{eta^2over 3}}is insufficient to determine either Q_{cc} or eta. However, two methods, Zeeman perturbed NQR powder pattern and ^{10}B NQR, can be employed to obtain both Q_{cc } and eta. An example is given for ^{11}B in CaO-B_2O_3. With a double coil tank circuit design, pure ^ {11}B NQR was used to determine the fraction of borons in BO_3 and BO _4 configurations in hydrated zinc borates. ^{11}B NMR and NQR were also used to study lead borate glasses. Small changes in Q_{cc} (less than 2%) and eta (less than 0.1) suggest that BO_3 units with non-bridging oxygens are not present in the lead borate glasses.

Mao, Degen

25

Explosives detection by nuclear quadrupole resonance (NQR)  

NASA Astrophysics Data System (ADS)

Pure nuclear quadrupole resonance (NQR) of 14N nuclei is quite promising as a method for detecting explosives such as RDX and contraband narcotics such as cocaine and heroin in quantities of interest. Pure NQR is conducted without an external applied magnetic field, so potential concerns about damage to magnetically encoded data or exposure of personnel to large magnetic fields are not relevant. Because NQR frequencies of different compounds are quite distinct, we do not encounter false alarms from the NQR signals of other benign materials. We have constructed a laboratory prototype NQR explosives detector which interrogates a volume of 300 liters (10 ft3). This paper presents abbreviated results from a demonstration of the laboratory prototype NQR explosives detector conducted at the Federal Aviation Administration Technical Center in May 1994 on RDX-based explosives.

Garroway, Allen N.; Buess, M. L.; Yesinowski, J. P.; Miller, J. B.; Krauss, Ronald A.

1994-10-01

26

Application of nuclear quadrupole resonance to the study of clathrates. sup 35 Cl NQR and crystallography of clathrated CCl sub 4  

Microsoft Academic Search

The ³⁵Cl nuclear quadrupole resonance (NQR) spectra of CClâ in more than 20 clathrates have been measured in the range 4-200 K. The crystal structures of CClâ\\/Dianin's compound (1), CClâ\\/Fe(AcAc)â (3), CClâ\\/Ni(SCN)â(3-MePy)â (4), and CClâ\\/Ni(exan)â(4,4â²-dm-2,2â²-bpy) (19) clathrates are also reported. Site symmetry and site multiplicity of the guest molecule in clathrates were determined by NQR spectroscopy and by x-ray crystallography.

Li Pang; E. A. C. Lucken; G. Bernardinelli

1990-01-01

27

Supramolecular synthon pattern in solid clioquinol and cloxiquine (APIs of antibacterial, antifungal, antiaging and antituberculosis drugs) studied by 35 Cl NQR, 1 H- 17 O and 1 H- 14 N NQDR and DFT\\/QTAIM  

Microsoft Academic Search

The quinolinol derivatives clioquinol (5-chloro-7-iodo-8-quinolinol, Quinoform) and cloxiquine (5-chloro-8-quinolinol) were\\u000a studied experimentally in the solid state via 35Cl NQR, 1H-17O and 1H-14N NQDR spectroscopies, and theoretically by density functional theory (DFT). The supramolecular synthon pattern of O–H···N\\u000a hydrogen bonds linking dimers and ?–? stacking interactions were described within the QTAIM (quantum theory of atoms in molecules)\\u000a \\/DFT (density functional theory)

Jolanta Natalia Latosi?ska; Magdalena Latosi?ska; Marzena Agnieszka Tomczak; Janez Seliger; Veselko Žagar

28

NMR and NQR parameters of the SiC-doped on the (4,4) armchair single-walled BPNT: a computational study.  

PubMed

The structural properties, NMR and NQR parameters in the pristine and silicon carbide (SiC) doped boron phosphide nanotubes (BPNTs) were calculated using DFT methods (BLYP, B3LYP/6-31G) in order to evaluate the influence of SiC-doped on the (4,4) armchair BPNTs. Nuclear magnetic resonance (NMR) parameters including isotropic (CS(I)) and anisotropic (CS(A)) chemical shielding parameters for the sites of various (13)C, (29)Si, (11)B, and (31)P atoms and quadrupole coupling constant (C ( Q )), and asymmetry parameter (? ( Q )) at the sites of various (11)B nuclei were calculated in pristine and SiC- doped (4,4) armchair boron phosphide nanotubes models. The calculations indicated that doping of (11)B and (31)P atoms by C and Si atoms had a more significant influence on the calculated NMR and NQR parameters than did doping of the B and P atoms by Si and C atoms. In comparison with the pristine model, the SiC- doping in Si(P)C(B) model of the (4,4) armchair BPNTs reduces the energy gaps of the nanotubes and increases their electrical conductance. The NMR results showed that the B and P atoms which are directly bonded to the C atoms in the SiC-doped BPNTs have significant changes in the NMR parameters with respect to the B and P atoms which are directly bonded to the Si atoms in the SiC-doped BPNTs. The NQR results showed that in BPNTs, the B atoms at the edges of nanotubes play dominant roles in determining the electronic behaviors of BPNTs. Also, the NMR and NQR results detect that the Fig. 1b (Si(P)C(B)) model is a more reactive material than the pristine and the Fig. 1a (Si(B)C(p)) models of the (4,4) armchair BPNTs. PMID:21625895

Baei, Mohammad T; Sayyad-Alangi, S Zahra; Moradi, Ali Varasteh; Torabi, Parviz

2011-05-28

29

A Study of Transition-Metal Organometallic Complexes Combining (35) Cl Solid-State NMR Spectroscopy and (35) Cl?NQR Spectroscopy and First-Principles DFT Calculations.  

PubMed

A series of transition-metal organometallic complexes with commonly occurring metal?chlorine bonding motifs were characterized using (35) Cl solid-state NMR (SSNMR) spectroscopy, (35) Cl nuclear quadrupole resonance (NQR) spectroscopy, and first-principles density functional theory (DFT) calculations of NMR interaction tensors. Static (35) Cl ultra-wideline NMR spectra were acquired in a piecewise manner at standard (9.4?T) and high (21.1?T) magnetic field strengths using the WURST-QCPMG pulse sequence. The (35) Cl electric field gradient (EFG) and chemical shielding (CS) tensor parameters were readily extracted from analytical simulations of the spectra; in particular, the quadrupolar parameters are shown to be very sensitive to structural differences, and can easily differentiate between chlorine atoms in bridging and terminal bonding environments. (35) Cl?NQR spectra were acquired for many of the complexes, which aided in resolving structurally similar, yet crystallographically distinct and magnetically inequivalent chlorine sites, and with the interpretation and assignment of (35) Cl?SSNMR spectra. (35) Cl?EFG tensors obtained from first-principles DFT calculations are consistently in good agreement with experiment, highlighting the importance of using a combined approach of theoretical and experimental methods for structural characterization. Finally, a preliminary example of a (35) Cl?SSNMR spectrum of a transition-metal species (TiCl4 ) diluted and supported on non-porous silica is presented. The combination of (35) Cl?SSNMR and (35) Cl?NQR spectroscopy and DFT calculations is shown to be a promising and simple methodology for the characterization of all manner of chlorine-containing transition-metal complexes, in pure, impure bulk and supported forms. PMID:23907813

Johnston, Karen E; O'Keefe, Christopher A; Gauvin, Régis M; Trébosc, Julien; Delevoye, Laurent; Amoureux, Jean-Paul; Popoff, Nicolas; Taoufik, Mostafa; Oudatchin, Konstantin; Schurko, Robert W

2013-08-01

30

NMR and NQR study of the electronic and structural properties of Al-Cu-Fe and Al-Cu-Ru quasicrystals  

SciTech Connect

[sup 27]Al and [sup 63,65]Cu NMR is reported for powdered stable Al-Cu-Fe and Al-Cu-Ru icosahedral quasicrystals and crystalline approximants, and for an Al-Pd-Mn single-grain quasicrystal. [sup 27]Al NQR spectra at 4.2 K were observed in Al-Cu-Fe and Al-Cu-Ru samples. From quadrupole-perturbed NMR spectra at different magnetic fields, and from zero-field NQR spectra, a wide distribution of local electric-field gradient (EFG) tensor components and principal-axis-system orientations was found at the Al site. A model EFG calculation based on a 1/1 Al-Cu-Fe approximant successfully explained the observed NQR spectra. The average local gradient is largely determined by the [ital p]-electron wave function at the Al site, while the width of the distribution is due to EFG lattice contribution. Comparison of [sup 63]Cu and [sup 27]Al NMR shows the EFG distribution at the two sites is similar, but the electronic contribution to the EFG is considerably smaller at the Cu site, in agreement with a more [ital s]-type wave function of the conduction electrons. Overall spread of EFG values is well reproduced by calculation based on the approximant. However, the experimental spectra indicate a much larger number of nonequivalent sites when compared with the simulated NQR spectra based on the 1/1 approximant. The short-range, local chemical order is well represented by the approximant, but differences in coordination must be included at intermediate range in the quasicrystal. Measured [sup 27]Al Knight shift, magnetic susceptibility, and nuclear spin-lattice relaxation time as a function of temperature indicate reduced density of states at the Fermi level by a factor of 7 or 8 from the value in Al metal, consistent with the notion of a pseudogap for these quasicrystals. No differences in measured parameters were detected as a function of composition of the quasicrystalline alloys.

Shastri, A.; Borsa, F.; Torgeson, D.R.; Shield, J.E.; Goldman, A.I. (Ames Laboratory, U.S. Department of Energy and Department of Physics Astronomy, Iowa State University, Ames, Iowa 50011 (United States))

1994-12-01

31

SQUID detected NMR and NQR. Superconducting Quantum Interference Device.  

PubMed

The dc Superconducting QUantum Interference Device (SQUID) is a sensitive detector of magnetic flux, with a typical flux noise of the order 1 muphi0 Hz(-1/2) at liquid helium temperatures. Here phi0 = h/2e is the flux quantum. In our NMR or NQR spectrometer, a niobium wire coil wrapped around the sample is coupled to a thin film superconducting coil deposited on the SQUID to form a flux transformer. With this untuned input circuit the SQUID measures the flux, rather than the rate of change of flux, and thus retains its high sensitivity down to arbitrarily low frequencies. This feature is exploited in a cw spectrometer that monitors the change in the static magnetization of a sample induced by radio frequency irradiation. Examples of this technique are the detection of NQR in 27Al in sapphire and 11B in boron nitride, and a level crossing technique to enhance the signal of 14N in peptides. Research is now focused on a SQUID-based spectrometer for pulsed NQR and NMR, which has a bandwidth of 0-5 MHz. This spectrometer is used with spin-echo techniques to measure the NQR longitudinal and transverse relaxation times of 14N in NH4ClO4, 63+/-6 ms and 22+/-2 ms, respectively. With the aid of two-frequency pulses to excite the 359 kHz and 714 kHz resonances in ruby simultaneously, it is possible to obtain a two-dimensional NQR spectrum. As a third example, the pulsed spectrometer is used to study NMR spectrum of 129Xe after polariza-tion with optically pumped Rb. The NMR line can be detected at frequencies as low as 200 Hz. At fields below about 2 mT the longitudinal relaxation time saturates at about 2000 s. Two recent experiments in other laboratories have extended these pulsed NMR techniques to higher temperatures and smaller samples. In the first, images were obtained of mineral oil floating on water at room temperature. In the second, a SQUID configured as a thin film gradiometer was used to detect NMR in a 50 microm particle of 195Pt at 6 mT and 4.2 K. PMID:9650797

Augustine, M P; TonThat, D M; Clarke, J

1998-03-01

32

NQR, NMR and Crystal Structure Studies of [C(NH2)3]2HgX4 (X = Br, I)  

NASA Astrophysics Data System (ADS)

The crystal structure of [C(NH2)3]2HgBr4 has been determined at room temperature: monoclinic, space group C2/c, with a = 10.035(2), b = 11.164(2), c = 13.358(3) Å, ? = 111.67(3)°, and Z = 4. The crystal consists of planar [C(NH2)3]+ and distorted tetrahedral [HgBr4]2- ions. The Hg atom is located on a two-fold axis such that two sets of inequivalent Br atoms exist in an [HgBr4]2- ion. In accordance with the crystal structure, two 81Br NQR lines widely separated in frequency were observed between 77 and ca. 380 K. [C(NH2)3]2HgI4 yielded four 127I NQR lines ascribable to m = ±1/2 ? ±3/2 transitions, indicating that its crystal structure is different from the bromide complex. The 1H NMR T 1 measurements showed a single minimum for the bromide but two minima for the iodide. The analyses based on the C3 reorientations of the planar [C(NH2)3]+ ions gave the activation energies of 29.8 kJ mol-1 for the bromide, and 30.2 and 40.0 kJ mol-1 for the iodide.

Furukawa, Y.; Terao, H.; Ishihara, H.; Gesing, T. M.; Buhl, J.-C.

2004-12-01

33

NMR and NQR study of Si-doped (6,0) zigzag single-walled aluminum nitride nanotube as n or P-semiconductors.  

PubMed

Density functional theory (DFT) calculations were performed to investigate the electronic structure properties of pristine and Si-doped aluminum nitride nanotubes as n or P-semiconductors at the B3LYP/6-31G* level of theory in order to evaluate the influence of Si-doped in the (6,0) zigzag AlNNTs. We extended the DFT calculation to predict the electronic structure properties of Si-doped aluminum nitride nanotubes, which are very important for production of solid-state devices and other applications. To this aim, pristine and Si-doped AlNNT structures in two models (Si(N) and Si(Al)) were optimized, and then the electronic properties, the isotropic (CS(I)) and anisotropic (CS(A)) chemical shielding parameters for the sites of various (27)Al and (14)N atoms, NQR parameters for the sites of various of (27)Al and (14)N atoms, and quantum molecular descriptors were calculated in the optimized structures. The optimized structures, the electronic properties, NMR and NQR parameters, and quantum molecular descriptors for the Si(N) and Si(Al) models show that the Si(N) model is a more reactive material than the pristine or Si(Al) model. PMID:22588584

Baei, Mohammad T; Peyghan, Ali Ahmadi; Tavakoli, Khadijeh; Babaheydari, Ali Kazemi; Moghimi, Masoumeh

2012-05-16

34

^63Cu NMR and NQR study of the stripe phase in La_1.6-xNd_0.40Sr_xCuO_4  

NASA Astrophysics Data System (ADS)

We find that the integrated intensity of ^63Cu NQR in La_1.6-xNd_0.40Sr_xCuO4 decreases dramatically below the stripe ordering temperature.(P.M. Singer et al.),Phys. Rev. B 60, 15345 (1999).(A.W. Hunt et al.),Phys. Rev. Lett. 82, 4300 (1999). Comparison with scattering results indicates that the missing signal represents the stripe order parameter. We observe that the loss of signal is sharpest for x ~1/8, indicating that x ~1/8 is the optimal concentration for stripe formation. This work was supported by the National Science Foundation (DMR 99-71266, DMR 98-08941), the A.P. Sloan Foundation, the Mitsui Foundation, and the Platzman Fund.

Singer, Philip M.; Hunt, Allen W.; Cederström, Agneta F.; Imai, Takashi

2000-03-01

35

NMR and NQR Studies on Non-centrosymmetric Superconductors Re7B3, LaBiPt, and BiPd  

NASA Astrophysics Data System (ADS)

We report the nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements for non-centrosymmetric superconductors Re7B3, LaBiPt, and BiPd containing heavy elements. For all three compounds, the spin--lattice relaxation rate 1/T1 shows a coherence peak just below Tc and decreases exponentially at low temperatures, which indicates that an isotropic superconducting gap is dominant in these compounds. In BiPd, the height of the coherence peak just below Tc is much suppressed, which suggests that there exists a substantial component of gap with nodes in this compound. Our results indicate that heavy element is not the only factor, but the extent of inversion symmetry breaking is also important to induce a large spin--orbit coupling and an unconventional superconducting state.

Matano, Kazuaki; Maeda, Satoki; Sawaoka, Hiroki; Muro, Yuji; Takabatake, Toshiro; Joshi, Bhanu; Ramakrishnan, Srinivasan; Kawashima, Kenji; Akimitsu, Jun; Zheng, Guo-qing

2013-08-01

36

Factors affecting the NQR line width in nitramine explosives  

Microsoft Academic Search

A number of factors associated with crystal quality contribute to the nuclear quadrupole resonance (NQR) line width. Imperfections\\u000a such as dislocations, voids, strain and impurities can be electrical sources that distort the electric field gradient at nearby\\u000a quadrupolar nuclei and broaden the observed NQR line. We measured the14N NQR line widths in powdered samples of the nitramine explosives hexahydro-1,3,5-trinitro-s-triazine (RDX),

M. L. Buess; S. M. Caulder

2004-01-01

37

(75)As, (63)Cu NMR and NQR characterization of selected arsenic minerals.  

PubMed

The direct measurement and identification of solid state arsenic phases using (75)As NMR is made difficult by the simultaneous conditions of large quadrupole moment and low coordination symmetry in many compounds. However, specific arsenic minerals can efficiently be detected and discriminated via nuclear quadrupolar resonance (NQR). We report on the first NMR and NQR measurements in the natural minerals enargite (Cu3AsS4), niccolite (NiAs), arsenopyrite (FeAsS) and loellingite (FeAs2). The NQR frequencies have been determined from both high-field NMR powder patterns and via zero-field frequency sweeps. Density functional theory (DFT) based ab initio calculations support the experimental results. The compounds studied here are common in terms of the known set of As-containing minerals. They are sometimes encountered in the context of base metal or gold mining. The study represents a significant addition to the list of arsenic minerals that can now be detected with NQR techniques. PMID:23706610

Lehmann-Horn, J A; Miljak, D G; Bastow, T J

2013-05-14

38

Single-spin fluid, spin gap, and [ital d]-wave pairing in YBa[sub 2]Cu[sub 4]O[sub 8]: A NMR and NQR study  

SciTech Connect

We present results of [sup 17]O and [sup 63,65]Cu nuclear magnetic resonance (NMR) and nuclear quadrupolar resonance (NQR) studies in the normal and superconducting state of the 82-K superconductor YBa[sub 2]Cu[sub 4]O[sub 8]. The various components of the Cu and O Knight-shift tensors show strong but similar temperature dependences over the temperature range from 8.5 to 300 K in both the CuO[sub 2] planes and the chains, supporting the picture that there is only one spin component in the planes and the chains, although with different susceptibilities. The oxygen data obey the Korringa relation. This may be interpreted as Fermi-liquid behavior of the electronic system far away from the antiferromagnetic wave vector. The temperature dependence of both the planar Cu and O shift tensors and the planar Cu spin-lattice relaxation rate suggest the opening of a pseudo-spin-gap well above [ital T][sub [ital c

Bankay, M.; Mali, M.; Roos, J.; Brinkmann, D. (Physik-Institut, Universitaet Zuerich, 8057 Zuerich (Switzerland))

1994-09-01

39

Site-directed mutagenesis of conserved cysteine residues in NqrD and NqrE subunits of Na+-translocating NADH:quinone oxidoreductase.  

PubMed

Each of two hydrophobic subunits of Na+-translocating NADH:quinone oxidoreductase (NQR), NqrD and NqrE, contain a pair of strictly conserved cysteine residues within their transmembrane alpha-helices. Site-directed mutagenesis showed that substitutions of these residues in NQR of Vibrio harveyi blocked the Na+-dependent and 2-n-heptyl-4-hydroxyquinoline N-oxide-sensitive quinone reductase activity of the enzyme. However, these mutations did not affect the interaction of NQR with NADH and menadione. It was demonstrated that these conserved cysteine residues are necessary for the correct folding and/or the stability of the NQR complex. Mass and EPR spectroscopy showed that NQR from V. harveyi bears only a 2Fe-2S cluster as a metal-containing prosthetic group. PMID:18298367

Fadeeva, M S; Bertsova, Y V; Verkhovsky, M I; Bogachev, A V

2008-02-01

40

Signal processing for NQR discrimination of buried land mines  

NASA Astrophysics Data System (ADS)

Nuclear quadrupole resonance (NQR) is a technique that discriminates mines from clutter by exploiting unique properties of explosives, rather than the attributes of the mine that exist in many forms of anthropic clutter. After exciting the explosive with a properly designed electromagnetic-induction (EMI) system, one attempts to sense late-time spin echoes, which are characterized by radiation at particular frequencies. It is this narrow-band radiation that indicates the presence of explosives, since this effect is not seen in most clutter, both natural and anthropic. However, this problem is complicated by several issues. First, the late-time radiation if often very weak, particularly for TNT, and therefore the signal-to-noise ratio must be high for extracting the NQR response. Further, the frequency at which the explosive radiates is often a strong function of the background environment, and therefore in practice the NQR radiation frequency is not known a priori. Finally, at the frequencies of interest, there is a significant amount of background radiation, which induces radio frequency interference (RFI). In this paper we discuss several signal processing tools we have developed to enhance the utility of NQR explosives detection. In particular, with regard to the RFI, we exposure least-mean-squares algorithms which have proven well suited to extracting background interference. Algorithm performance is assessed through consideration of actual measured data. With regard to the detection of the NQR electromagnetic echo, we consider a Bayesian discrimination algorithm. The performance of the Bayesian algorithm is presented, again using measured NQR data.

Tantum, Stacy L.; Collins, Leslie M.; Carin, Lawrence; Gorodnitsky, Irina; Hibbs, Andrew D.; Walsh, David O.; Barrall, Geoffrey A.; Gregory, Dave; Matthews, Robert; Vierkoetter, Stephie A.

1999-08-01

41

NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts. Quarterly technical progress report, June 15--September 15, 1991  

SciTech Connect

Our previous studies (1,2) on the zerofield NMR spectra of Cu/Co catalysts revealed that the method of preparation sensitively influences the magnetic character of the Catalyst. Catalytic studies of the earlier investigators also (3) show similar influence on the product selectivity and indicate reproducible performance is critically dependent on the control and rigor of the preparation technique. To compliment the NMR results, we have made a thorough investigation of the Hysteresis character of the Cu/Co catalysts with the metal ratio varying from 0.2 to 4.0.

Not Available

1991-12-17

42

NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts. Quarterly technical progress report, September 15--December 15, 1992  

SciTech Connect

We have investigated a series of Cu/Co catalysts supported on Titanium Dioxide. This study has sought to examine and compare the nature and effect of the supports Chromia and Titania (Cr{sub 2}O{sub 3}, and TiO{sub 2}) on the magnetic character of the Cu-Co-Cr and Cu-Co-TiO{sub 2} catalysts. The magnetization results for Cu/Co, Cu/Co/Cr, Cu/Co/TiO{sub 2} system are presented along with the magnetization data for the unsupported Cu/Co catalysts and data for supported catalysts. Pure cobalt metal has a magnetic moment of 161 emu/g. The measured emu values and the corresponding reduction percentages are given for the various catalysts investigated. The vibration sample magnetometer determines S{sub s}, the saturation magnetization, emu per gram of the composite sample. The magnetization values reported are emu per gram of cobalt in the composite. As such the data normally reflects the proportion of cobalt metal that is reduced to metallic form. However, if electronic exchanges occur between cobalt and other elements in the system, the magnetic moment itself differs from the assumed value of 161 emu/g Co then the emu value observed will be the resultant due to the electronic charge density modifications in Co as well as reduction to metallic state. Our earlier NMR studies reveal such electronic structural modifications occur for Cobalt in Cu-Co and Co-TiO{sub 2} systems. The magnetization data in column 3 for Cu-Co-TiO{sub 2} systems unambiguously shows such electron exchanges do occur between cobalt and titania.

Murty, A.N.

1992-12-31

43

Local magnetic and structural properties of the low-temperature orthorhombic to low-temperature tetragonal transition: A 139La NQR study in lightly hole-doped La1.8-xEu0.2SrxCuO4  

Microsoft Academic Search

139La nuclear quadrupole resistance (NQR) and relaxation measurements in lightly hole-doped La1.8-xEu0.2SrxCuO4 have been used to investigate the microscopic properties of the low-temperature orthorhombic to low-temperature tetragonal transition. The transition is characterized by a sharp peak in 139La NQR relaxation rate, indicating phonon softening. We find that the structural phase transition is accompanied by a modification of the spin state.

B. J. Suh; P. C. Hammel; M. Hücker; B. Büchner

1999-01-01

44

The single NqrB and NqrC subunits in the Na(+)-translocating NADH: quinone oxidoreductase (Na(+)-NQR) from Vibrio cholerae each carry one covalently attached FMN.  

PubMed

The Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR) is the prototype of a novel class of flavoproteins carrying a riboflavin phosphate bound to serine or threonine by a phosphodiester bond to the ribityl side chain. This membrane-bound, respiratory complex also contains one non-covalently bound FAD, one non-covalently bound riboflavin, ubiquinone-8 and a [2Fe-2S] cluster. Here, we report the quantitative analysis of the full set of flavin cofactors in the Na(+)-NQR and characterize the mode of linkage of the riboflavin phosphate to the membrane-bound NqrB and NqrC subunits. Release of the flavin by ?-elimination and analysis of the cofactor demonstrates that the phosphate group is attached at the 5'-position of the ribityl as in authentic FMN and that the Na(+)-NQR contains approximately 1.7mol covalently bound FMN per mol non-covalently bound FAD. Therefore, each of the single NqrB and NqrC subunits in the Na(+)-NQR carries a single FMN. Elimination of the phosphodiester bond yields a dehydro-2-aminobutyrate residue, which is modified with ?-mercaptoethanol by Michael addition. Proteolytic digestion followed by mass determination of peptide fragments reveals exclusive modification of threonine residues, which carry FMN in the native enzyme. The described reactions allow quantification and localization of the covalently attached FMNs in the Na(+)-NQR and in related proteins belonging to the Rhodobacter nitrogen fixation (RNF) family of enzymes. This article is part of a Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012). PMID:22366169

Casutt, Marco S; Schlosser, Andreas; Buckel, Wolfgang; Steuber, Julia

2012-02-16

45

NQR spin-echo methods at very low temperatures  

NASA Astrophysics Data System (ADS)

Pulsed methods may be successfully used in very low temperature NMR or NQR experiments provided good thermal anchoring of the sample is achieved. In order to reduce heating effects, it is advantageous to use rf pulses that are shorter than the standard magnetization tipping pulses used at higher temperatures. The present work describes the use of short nonstandard rf pulses in NQR spin-echo experiments on powdered samples. Theoretical density matrix calculations have been carried out, and the resulting expression for the echo amplitude confirmed by experiment. Measurements were made on a powder sample of high-purity semimetallic arsenic using a sample probe designed for use in a dilution refrigerator. Preliminary spin-lattice relaxation-time measurements show that the Korringa relation holds in arsenic down to 150 mK.

Goudemond, I. P.; Keartland, J. M.; Hoch, M. J. R.

1991-03-01

46

14 N NQR spectra of complexes between hexamethylenetetramine and the crystalline hydrates of salts  

Microsoft Academic Search

Nuclear quadrupole resonance has recently been used more and more effective along with such traditional methods as vibrational spectroscopy and proton magnetic resonance to investigate hydrogen bonding. The NQR method on 14N nuclei has been put into practice at a later date than on the chlorine nuclei. This is explained by the low intensity of the 14N NQR signals and

é. O. Azizov; V. S. Grechishkin; T. G. Balicheva; I. V. Pologikh

1979-01-01

47

Temperature-Induced Change in the Magnitude of the Effective Density of States: A NQR/NMR Study of the A-Site-Ordered Perovskite System CaCu3Ru4O12  

NASA Astrophysics Data System (ADS)

NQR/NMR measurements, including spin-lattice relaxation rate (1/T1) and Knight shift (K) evaluations, have been carried out for Cu and Ru nuclear spins in the A-site ordered perovskite system CaCu3Ru4O12, which exhibits a mass-enhancement-like behavior although it possesses no f electrons. The temperature evolution of T1 for Cu, which was measured up to 700 K, exhibits 1/T1T = constant behavior at high enough temperatures. This clearly denies the existence of a Cu localized moment, which was previously suggested as the origin of the mass enhancement in a dense Kondo scenario. Furthermore, K and (1/T1T) for Cu exhibit significant temperature dependences with two characteristic temperatures TF=20 K and TX=180 K, suggesting a temperature-induced transition of microscopic electronic character at TF and TX. We propose a two-band model, where the effective density of states for one of the bands shows a significant temperature dependence in TF

Kato, Harukazu; Tsuruta, Takuya; Matsumura, Masahiro; Nishioka, Takashi; Sakai, Hironori; Tokunaga, Yo; Kambe, Shinsaku; Walstedt, Russell E.

2009-05-01

48

Local magnetic and structural properties of the low-temperature orthorhombic to low-temperature tetragonal transition: A ¹³⁹La NQR study in lightly hole-doped La{sub 1.8-x}Eu{sub 0.2}SrâCuOâ  

Microsoft Academic Search

¹³⁹La nuclear quadrupole resistance (NQR) and relaxation measurements in lightly hole-doped La{sub 1.8-x}Eu{sub 0.2}SrâCuOâ have been used to investigate the microscopic properties of the low-temperature orthorhombic to low-temperature tetragonal transition. The transition is characterized by a sharp peak in ¹³⁹La NQR relaxation rate, indicating phonon softening. We find that the structural phase transition is accompanied by a modification of the

B. J. Suh; P. C. Hammel; M. Huecker; B. Buechner

1999-01-01

49

Enhancing nuclear quadrupole resonance (NQR) signature detection leveraging interference suppression algorithms  

NASA Astrophysics Data System (ADS)

Nuclear quadrupole resonance (NQR) is a radio frequency (RF) magnetic spectroscopic technique that has been shown to detect and identify a wide range of explosive materials containing quadrupolar nuclei. The NQR response signal provides a unique signature of the material of interest. The signal is, however, very weak and can be masked by non-stationary RF interference (RFI) and thermal noise, limiting detection distance. In this paper, we investigate the bounds on the NQR detection range for ammonium nitrate. We leverage a low-cost RFI data acquisition system composed of inexpensive B-field sensing and commercial-off-the-shelf (COTS) software-defined radios (SDR). Using collected data as RFI reference signals, we apply adaptive filtering algorithms to mitigate RFI and enable NQR detection techniques to approach theoretical range bounds in tactical environments.

DeBardelaben, James A.; Miller, Jeremy K.; Myrick, Wilbur L.; Miller, Joel B.; Gilbreath, G. Charmaine; Bajramaj, Blerta

2012-05-01

50

Sb NQR in filled skutterudites MFe 4Sb 12 (M=Na, Ca, La)  

Microsoft Academic Search

Temperature-dependent nuclear quadrupole resonance (NQR) investigations on the 121,123Sb nuclei in filled skutterudites MFe4Sb12 (M=Na, Ca, La) are reported. These new compounds show a nice interplay of ferromagnetic and antiferromagnetic correlations best seen in the relaxation rate. Substructures observed in the 121,123Sb NQR spectra give strong evidence for static (or dynamic) disorder on the filler site. Therefore, we performed ab-initio

A. A. Gippius; E. N. Morozova; K. S. Okhotnikov; E. A. Alkaev; A. V. Shevelkov; M. Baenitz; A. Leithe-Jasper; H. Rosner; R. Viennois; Yu. Grin; F. Steglich

2006-01-01

51

Possible stripe fluctuations in La2 - x - yNdySrxCuO4 at room temperature observed by 63Cu NQR spectroscopy  

NASA Astrophysics Data System (ADS)

63Cu nuclear quadrupole resonance (NQR) studies at room temperature were reported on six Nd-doped La2 - xSrxCuO4 samples. The NQR spectrum for La1.48Nd0.4Sr0.12CuO4 has a different line shape compared with those from the other samples, which is similar to the case of the insulating La2CuO4. This may suggest that the stripe fluctuations at such a special Nd and Sr doping fall into the frequency window of 63Cu NQR. The spectra of the other five samples were analysed by pairs of 63Cu and 65Cu Gaussians at A and B sites. The full width of half-maxim (FWHM) for 63Cu at B sites is anomalously large for La1.45Nd0.4Sr0.15CuO4, which was considered to be related to the stripe fluctuations.

Zhang, Q.-M.; Ying, X. N.; Gu, M.; Wang, Y. N.

2005-04-01

52

Application of a dc SQUID to rf amplification: NQR  

SciTech Connect

Superconducting QUantum Interference Devices (SQUIDs) have been used for more than a decade for the detection of magnetic resonance. Until recently, these devices had mostly been confined to operation in the audiofrequency range, so that experiments have been restricted to measurements of resonance at low frequencies, or of changes in the static susceptibility of a sample induced by rf irradiation at the resonant frequency. However, the recent extension of the operating range of low noise dc SQUIDs to radiofrequencies (rf) allows one to detect magnetic resonance directly at frequencies up to several hundred megahertz. In this paper, we begin by summarizing the properties of dc SQUIDs as tuned rf amplifers. We then describe first, the development of a SQUID system for the detection of pulsed nuclear quadrupole resonance (NQR) at about 30 MHz and second, a novel technique for observing magnetic resonances in the absence of any externally applied rf fields.

Hilbert, C.; Clarke, J.; Sleator, T.; Hahn, E.L.

1985-05-01

53

^63Cu NQR relaxation in the p-type transparent conductor CuScO_2:Mg  

NASA Astrophysics Data System (ADS)

Transparent conducting oxides with p-type conductivity are of interest as electronic complements to the more familiar n-type transparent conductors. This paper reports the first results of a study of carrier spin dynamics in p-type CuScO_2:Mg using ^63Cu nuclear spin-lattice relaxation measurements. Relaxation rates 1/T1 have been measured by nuclear quadrupole resonance (NQR) over the range 280 K to 400 K. The ^63Cu NQR frequency is found to be 28,135 ± 5 kHz at 300 K and to decrease linearly with temperature over the experimental range. The value of 1/T1 at 300 K is 130 ± 10 s-1. The rate is weakly dependent on temperature and increases by only about 15 % up to 400 K. This behavior contrasts sharply with results obtained previously(1. A. Rajabzadeh, J. Tate and W. Warren, Bull. Am. Phys. Soc. 48, 1009 (2003).) for the related material CuYO_2:Ca. In that material, relaxation rates for ^63Cu and ^65Cu were strongly temperature dependent, being approximately thermally-activated with activation energy 152 ± 10 meV. The nuclear relaxation properties of CuScO_2:Mg are suggestive of more conventional metallic transport in CuScO_2:Mg compared with CuYO_2:Ca.

Rossi, Vincent; Tate, Janet; Warren, William; Li, Jun; Sleight, Arthur

2003-05-01

54

Semiempirical quantum mechanical calculations of electronic distribution and NQR parameters of bromine atoms in some organic and inorganic compounds  

Microsoft Academic Search

The Br electric field gradient (EFG) for some organic and inorganic compounds was calculated using a semi-empirical method. The nuclear quadrupole resonance (NQR) frequencies and asymmetry parameters of the bromine atoms in these compounds have also been evaluated. Quantitative correlation of the NQR frequencies and asymmetry parameters of the EFG of bromine nuclei with the population of p orbitals of

N. L Hadipour; S Javadian

2000-01-01

55

Oxidant-induced formation of a neutral flavosemiquinone in the Na+-translocating NADH:Quinone oxidoreductase (Na+-NQR) from Vibrio cholerae.  

PubMed

The Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR) from the human pathogen Vibrio cholerae is a respiratory flavo-FeS complex composed of the six subunits NqrA-F. The Na(+)-NQR was produced as His(6)-tagged protein by homologous expression in V. cholerae. The isolated complex contained near-stoichiometric amounts of non-covalently bound FAD (0.78 mol/mol Na(+)-NQR) and riboflavin (0.70 mol/mol Na(+)-NQR), catalyzed NADH-driven Na(+) transport (40 nmol Na(+)min(-1) mg(-1)), and was inhibited by 2-n-heptyl-4-hydroxyquinoline-N-oxide. EPR spectroscopy showed that Na(+)-NQR as isolated contained very low amounts of a neutral flavosemiquinone (10(-3) mol/mol Na(+)-NQR). Reduction with NADH resulted in the formation of an anionic flavosemiquinone (0.10 mol/mol Na(+)-NQR). Subsequent oxidation of the Na(+)-NQR with ubiquinone-1 or O(2) led to the formation of a neutral flavosemiquinone (0.24 mol/mol Na(+)-NQR). We propose that the Na(+)-NQR is fully oxidized in its resting state, and discuss putative schemes of NADH-triggered redox transitions. PMID:18454933

Tao, Minli; Casutt, Marco S; Fritz, Günter; Steuber, Julia

2008-04-11

56

Determination of the electric field gradient tensor by 2D NQR  

Microsoft Academic Search

For a full specification of the Electric Field Gradient (EFG) tensor, five independent parameters are necessary: the asymmetry parameter (?), the largest component of the EFG (eq), and three angles which determine the orientation of the EFG principal axis with respect to the crystallographic frame. The parameters eq and ? can be determined independently by pure Nuclear Quadrupole Resonance (NQR)

C. R. Hernán; S. R. Rabbani; Christovam Mendonça

1997-01-01

57

In-Situ Real Time Detection of Explosive/Chemical Compounds in Mines Using Nuclear Quadrupole Resonance (NQR).  

National Technical Information Service (NTIS)

This program was part of DARPA's 'Dog Nose' initiative to develop land mine detection technology based upon the chemical signature of the mine explosive charge. Nuclear quadrupole resonance (NQR) was the only technology pursued that detects the bulk explo...

A. D. Hibbs

2001-01-01

58

Nuclear quadrupole resonance study of hydrogen bonded solid materials.  

PubMed

Nuclear quadrupole resonance is presented as a method for the study of solid hydrogen bonded materials. NQR study of hydrogen bonds in ferroelectric and paraelectric KH2PO4, antiferroelectric and paraelectric squaric acid, ferroelectric croconic acid and antiferroelectric and paraelectric cocrystal 5'-dimethyl-2, 2'-bipyridine - chloranilic acid (1:1) are discussed in more details. A 14N NQR study of the strong short O-HKN hydrogen bond in two polymorphic forms of cocrystal isonicotinamide-oxalic acid (2:1) is presented as well. Various correlations between the NQR parameters and between the NQR and structural parameters have been observed. These correlations may be used to determine the proton position in a hydrogen bond and some other structural parameters from the NQR data. PMID:24062106

Seliger, Janez

2011-09-01

59

Measurement of in-situ stress in salt and rock using NQR techniques  

Microsoft Academic Search

A discussion of how stress and strain affect the quantities which can be measured in an NQR experiment shows that, for stresses of the magnitude to be expected at depths up to about 10,000 feet, quadrupole coupling constants will fall in the range of 1 to 10 kHz for both the sodium and chloride ions in NaCl. The most promising

E. Schempp; T. Hirschfeld; S. Klainer

1980-01-01

60

Basic aspects and main results of NMR-NQR spectroscopies in high-temperature superconductors  

NASA Astrophysics Data System (ADS)

After a mention of the structural, magnetic and electronic properties of high-temperature superconductors (HTSC), the basic principles of NMR-NQR experiments in these compounds are presented, emphasizing the marked differences and the novel aspects of the latter systems in comparison with metals and conventional superconductors. It follows a review of NMR-NQR spectra and relaxation rates in two-dimensional quantum antiferromagnets (particularly 0034-4885/61/10/002/img1) driven towards the superconducting state by charge doping. The main results obtained in the normal state of HTSC are summarized, while the problems of the spin-gap and of the superconducting fluctuations are discussed to a certain extent, by including the most recent contributions. An overview is given on the main conclusions derived from NMR-NQR experiments in the superconducting state. A section is devoted to the insights into the vortex lattice and the flux lines motion that have been obtained from NMR line narrowing, 0034-4885/61/10/002/img2 and echo dephasing. This review deals mostly with three systems, 0034-4885/61/10/002/img3, 0034-4885/61/10/002/img4 and 0034-4885/61/10/002/img5.

Rigamonti, A.; Borsa, F.; Carretta, P.

1998-10-01

61

Radio-frequency tunable atomic magnetometer for detection of solid-state NQR  

NASA Astrophysics Data System (ADS)

We constructed a potassium atomic magnetometer which resonantly detects rf magnetic fields with subfemtotesla sensitivity. The resonance frequency is set by the Zeeman resonance of the potassium atoms in a static magnetic field applied to the magnetometer cell. Strong optical pumping of the potassium atoms into a stretched state reduces spin-exchange broadening of the Zeeman resonance, resulting in relatively small linewidth of about 200 Hz (half-width at half-maximum). The magnetometer was used to detect ^14N NQR signal from powdered ammonium nitrate at 423 kHz, with sensitivity an order of magnitude higher than with a conventional room temperature pickup coil with comparable geometry. The demonstrated sensitivity of 0.24 fT/Hz^1/2 can be improved by several means, including use of higher power lasers for pumping and probing. Our technique can potentially be used to develop a mobile, open-access NQR spectrometer for detection of nitrogen-containing solids of interest in security applications.

Lee, S.-K.; Sauer, K. L.; Seltzer, S. J.; Alem, O.; Romalis, M. V.

2007-06-01

62

Novel superconducting characteristics and unusual normal-state properties in iron-based pnictide superconductors: 57FeNMR and 75AsNQR/NMR studies in REFeAsO1-y (RE = La, Pr, Nd) and Ba0.6K0.4Fe2As2  

NASA Astrophysics Data System (ADS)

We discuss the novel superconducting characteristics and unusual normal-state properties of iron (Fe)-based pnictide superconductors REFeAsO1-y (RE = La, Pr, Nd) and Ba0.6K0.4Fe2As2 (Tc = 38 K) by means of 57FeNMR and 75AsNQR/NMR. In the superconducting state of LaFeAsO0.7 (Tc = 28 K), the spin component of the 57Fe-Knight shift decreases to almost zero at low temperatures, which provide firm evidence of the superconducting state formed by spin-singlet Cooper pairing. The nuclear spin-lattice relaxation rates (1/T1) in LaFeAsO0.7 and Ba0.6K0.4Fe2As2 exhibit a T3-like dependence without a coherence peak just below Tc, indicating that an unconventional superconducting state is commonly realized in these Fe-based pnictide compounds. All these events below Tc are consistently argued in terms of an extended s±-wave pairing with a sign reversal of the order parameter among Fermi surfaces. In the normal state, 1/T1T decreases remarkably upon cooling for both the Fe and As sites of LaFeAsO0.7. In contrast, it gradually increases upon cooling in Ba0.6K0.4Fe2As2. Despite the similarity between the superconducting properties of these compounds, a crucial difference was observed in their normal-state properties depending on whether electrons or holes are doped into the FeAs layers. These results may provide some hint to address a possible mechanism of Fe-based pnictide superconductors.

Mukuda, H.; Terasaki, N.; Yashima, M.; Nishimura, H.; Kitaoka, Y.; Iyo, A.

2009-05-01

63

Korormicin insensitivity in Vibrio alginolyticus is correlated with a single point mutation of Gly-140 in the NqrB subunit of the Na(+)-translocating NADH-quinone reductase.  

PubMed

Na(+)-translocating NADH-quinone reductase (NQR) from the marine Vibrio alginolyticus is strongly inhibited by a new antibiotic korormicin. Korormicin specifically inhibits the Na(+)-dependent reaction of the NQR complex and acts as a purely non-competitive inhibitor for Q-1 with the inhibitor constant of 82 pM. Korormicin-resistant mutants were isolated from V. alginolyticus and the NQR complex was purified from a mutant KR2. Similar to 2-n-heptyl-4-hydroxyquinoline N-oxide (HQNO), korormicin acted as a purely noncompetitive inhibitor to the NQR complex from the mutant KR2, but the inhibitor constant increased to 8 microM, which is 10(5)-fold higher than that of the wild-type NQR complex. The inhibitor constant of HQNO, however, was only slightly affected by the acquisition of korormicin resistance. The spontaneous mutation was caused by a single mutation of G-422 to T-422 in the nucleotide sequence of the nqrB gene, which resulted in the conversion of Gly-140 to Val-140. Thus, Gly-140 seems to play an important role for the binding of korormicin to the NqrB subunit. The fact that korormicin is a purely noncompetitive inhibitor for Q-1 strongly supports the presence of one of Q-1 binding sites in the NqrB subunit, which also has a covalently bound FMN at Thr-235. PMID:12054467

Hayashi, Maki; Shibata, Naoaki; Nakayama, Yuji; Yoshikawa, Kazuhiro; Unemoto, Tsutomu

2002-05-15

64

I: Low Frequency NMR and NQR Using a dc SQUID. II: Variable-temperature 13C CP/MAS of Organometallics  

SciTech Connect

NMR and NQR at low frequencies are difficult prospects due to small nuclear spin polarization. Furthermore, the sensitivity'of the inductive pickup circuitry of standard spectrometers is reduced as the frequency is lowered. I have used a cw-SQUID (Superconducting QUantum Interference Device) spectrometer, which has no such frequency dependence, to study the local atomic environment of {sup 14}N via the quadrupolar interaction. Because {sup 14}N has spin I = 1 and a 0-6 MHz frequency range, it is not possible to obtain well-resolved spectra in high magnetic fields. I have used a technique to observe {sup 14}N NQR resonances via their effect on neighboring protons mediated by the heteronuclear dipolar interaction to study peptides and narcotics. The sensitivity of the SQUID is not enough to measure low-frequency surface (or other low spin density) systems. The application of spin-polarized xenon has been previously used to enhance polarization in conventional NMR experiments. Because xenon only polarizes spins with which it is in contact, it is surface selective. While differences in chemical shifts between surface and bulk spins are not large, it is expected that the differences in quadrupole coupling constant should be very large due to the drastic change of the electric field gradient surrounding spins at the surface. With this in mind, I have taken preliminary steps to measure SQUID detected polarization transfer from Xe to another spin species at 4.2 K and in small magnetic fields (<50 G). In this regime, the spin-lattice relaxation of xenon is dependent on the applied magnetic field. The results of our efforts to characterize the relaxation of xenon are presented. The final section describes the solid-state variable-temperature (VT) one- and two-dimensional {sup 13}C cross polarization (CP)/magic angle spinning (MAS) NMR of Hf({eta}{sup 5}-C{sub 5}H{sub 5}){sub 2}({eta}{sup 1}-C{sub 5}H{sub 5}){sub 2}, Zr({eta}{sup 5}-C{sub 5}H{sub 5}){sub 3}({eta}{sup 1}-C{sub 5}H{sub 5}) and Sn({eta}{sup 1}-C{sub 5}H{sub 5}){sub 4}. This work was undertaken in the hope of gaining insight into the intramolecuhrr dynamics, specifically which fluxional processes exist in the solid state, by what mechanism rearrangements are occurring, and the activation energies by which these processes are governed.

Ziegeweid, M.A.

1995-11-29

65

Electronic properties of LaO1-xFxFeAs in the normal state probed by NMR/NQR  

NASA Astrophysics Data System (ADS)

We report 139La, 57Fe and 75As nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements on powders of the new LaO1-xFxFeAs superconductor for x=0 and 0.1 at temperatures up to 480 K, and compare our measured NQR spectra with local density approximation (LDA) calculations. For all three nuclei in the x=0.1 material, it is found that the local Knight shift increases monotonically with an increase in temperature, and scales with the macroscopic susceptibility, suggesting a single magnetic degree of freedom. Surprisingly, the spin lattice relaxation rates for all nuclei also scale with one another, despite the fact that the form factors for each site sample different regions of q-space. This result suggests a lack of any q-space structure in the dynamical spin susceptibility that might be expected in the presence of antiferromagnetic correlations. Rather, our results are more compatible with simple quasi-particle scattering. Furthermore, we find that the increase in the electric field gradient at the As cannot be accounted for by LDA calculations, suggesting that structural changes, in particular the position of the As in the unit cell, dominate the NQR response.

Grafe, H.-J.; Lang, G.; Hammerath, F.; Paar, D.; Manthey, K.; Koch, K.; Rosner, H.; Curro, N. J.; Behr, G.; Werner, J.; Leps, N.; Klingeler, R.; Klauss, H.-H.; Litterst, F. J.; Büchner, B.

2009-03-01

66

NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts  

SciTech Connect

During this period, we focused our attention in analyzing the magnetic nature of the extensively used trimetallic catalyst system Cu-Co-Cr for the production of higher alcohols. We believe that there could be some correspondence between the catalytic and magnetic behaviors of the transition metal catalyst systems. Both the morphology and metallic charge distribution of the particles are know to govern the catalytic as well as the magnetic properties of the system. Based on this concept, we have extensively examined the Cu/Co system varying Cu/Co ratio from 0.2--4.0. Spectroscopic results are outlined herein. (VC)

Not Available

1992-04-15

67

Field-tuned critical fluctuations in YFe2Al10: Evidence from magnetization, 27Al NMR, and NQR investigations  

NASA Astrophysics Data System (ADS)

We report magnetization, specific heat, and NMR investigations on YFe2Al10 over a wide range of temperature and magnetic field and zero field (NQR) measurements. Magnetic susceptibility, specific heat, and spin-lattice relaxation rate divided by T(1/T1T) follow a weak power law (˜T-0.4) temperature dependence, which is a signature of the critical fluctuations of Fe moments. The value of the Sommerfeld-Wilson ratio and the linear relation between 1/T1T and ? suggest the existence of ferromagnetic correlations in this system. No magnetic ordering down to 50 mK in Cp(T)/T and the unusual T and H scaling of the bulk and NMR data are associated with a magnetic instability which drives the system to quantum criticality. The magnetic properties of the system are tuned by field wherein ferromagnetic fluctuations are suppressed and a crossover from quantum critical to Fermi-liquid behavior is observed with increasing magnetic field.

Khuntia, P.; Strydom, A. M.; Wu, L. S.; Aronson, M. C.; Steglich, F.; Baenitz, M.

2012-12-01

68

Synthesis and phtoluminescence study of Microporous Metal Organic Frameworks (MMOFs) for sensing and detection of nitroexplosives and aromatic compounds  

NASA Astrophysics Data System (ADS)

Due to the increased terrorist activity worldwide and the use of modern bombs in those attacks, the development of a new method capable of rapidly and cost-efficiently detecting trace vapor of explosives is highly desirable. Chemical explosives composed of a diverse group of compounds, including nitroaromatics, nitramines, nitrate esters as well as some inorganic/organic nitrates and peroxides. Current methodologies include use of well trained dogs and sophisticated instrumentation such as gas chromatography coupled with a mass spectrometer, nuclear quadruple resonance, ionization mass spectrometry (IMS). These methods are highly sensitive and selective, but often expensive, not always easily accessible, and require intense training for operation. As a complementary method, chemical sensors can provide new ways to the rapid detection of ultra trace explosives, and can be easily incorporated into inexpensive and portable microelectronic devices. Fluorescence based sensors utilizing conjugated polymers have attracted enormous attention in the recent years for their excellent performance. In this thesis, a systematic study was performed in a series of luminescent MMOFs and their behavior upon exposure to the vapor of different analytes. For example, [Zn2(oba)2(bpy)]·DMA, one of the MMOFs made of paddle-wheel SBU, selectively responds to nitroaromatics (with electron-withdrawing groups) and other aromatic compounds, like benzene, toluene (with electron-donating groups) via fluorescent quenching and enhancement respectively. The study also shows that nitro-containing non-aromatic analytes (nitroaliphatics) make negligible effect on the fluorescence of [Zn2(oba)2(bpy)]·DMA . The results demonstrate the exceptional ability of this particular MMOF to selectively detect explosives of different types (e.g. aromatic DNT vs. non-aromatic or aliphatic DMNB). Another series of highly luminescent MMOFs made of the same metal center (Zn) and similar ligands (bpdc, bpy, 2,2'dmbpy and bpe) but different structures have also been investigated. Photoluminescence studies show that the guest-free samples of these compounds also exhibit quenching or enhancement phenomena, when exposed to the vapors of two different types of analyte molecules having electron rich and electron deficient functional groups. The origin of such effect can be well understood and explained based on molecular orbital and band structure calculations, as well as the comparison of their redox potentials. In addition, synthesis and characterization of some new MMOFs, composed of V-shaped dicarboxylic acid and selected diamine ligands are briefly discussed. Clearly, ligands play an important role in the crystal structure formation as well as pore characteristics of the resultant MMOFs.

Pramanik, Sanhita

69

Isotope effect on the temperature dependence of the 35Cl NQR frequency in (NH4)2RuCl6  

NASA Astrophysics Data System (ADS)

35Cl NQR of (NH4)2RuCl6, (ND4)2RuCl6, (NH4)2SnCl6, and (ND4)2SnCl6 was measured.Isotope effect on the spatial distribution of hydrogen atoms is discussed.Tunneling splittings of torsional ground state of ammonium ions were estimated.Origin of T1Q anomaly previously reported in (NH4)2SnCl6 and (ND4)2SnCl6 was revealed.

Kume, Yoshio; Amino, Daiki; Asaji, Tetsuo

2013-07-01

70

/sup 79/ /sup 81/Br NQR spectra of bromochalcogenide complexes of Au(III), Pt(IV), and Pd(II)  

SciTech Connect

The structure of bromochalcogenide complexes of gold, platinum, and palladium, viz., AuBr/sub 4/ x SeBr/sub 3/, PtBr/sub 6/(SeBr/sub 3/)/sub 2/, PtBr/sub 6/(TeBr/sub 3/)/sub 2/, and PdBr/sub 2/(SeBr/sub 2/)/sub 2/, has been established with the aid of the NQR spectra of the bromine atoms. In the compounds of gold and platinum investigated SeBr/sub 3/ groupings are coordinated as ligands, and in the palladium complex SeBr/sub 2/ groupings serve as ligands.

Fokina, Z.A.; Kuznetsov, S.I.; Timoshchenko, N.I.; Bryukhova, E.V.

1987-01-10

71

NQR investigation of pressure-induced charge transfer in oxygen-deficient YBa sub 2 Cu sub 3 O sub 7-. delta. (. delta. = 0. 38)  

SciTech Connect

Measurements of the pressure dependence of {sup 63}Cu nuclear quadrupole frequency in YBa{sub 2}Cu{sub 3}O{sub 6.62} from ambient pressure up to 1.5 GPa at 4k have been performed. {Tc} was found to increase with pressure: d{Tc}/dp {approximately} 5 K/GPa. All observed NQR lines are linear in pressure: dln{nu}{sub Q}/dp=z. We found positive z for the empty chain sites, consistent with ionic (Cu{sup 1+}) configuration in which the atom simply feels a squeezing lattice. Planar coppers close to the empty chains have positive z, while those that are close to full chains have z {approximately} 0. We present an analysis of the NQR result on the basis of the charge transfer model in which the mobile charges migrate from the chain to the plane sites. We deduced that a transfer of 0.021 holes to the O(2,3) sites would explain the result in YBa{sub 2}Cu{sub 3}O{sub 6.62}, whereas only 0.007 holes transfer in fully oxygenated YBa{sub 2}Cu{sub 3}O{sub 7}.

Reyes, A.P.; Ahrens, E.T.; Hammel, P.C.; Heffner, R.H. (Los Alamos National Lab., NM (United States)); Takigawa, M. (International Business Machines Corp., Yorktown Heights, NY (United States). Thomas J. Watson Research Center)

1992-01-01

72

Nuclear Quadrupole Resonance Studies of Charge Distributions in Molecular Solids.  

NASA Astrophysics Data System (ADS)

A detailed description of an NMR-NQR double resonance spectrometer designed and constructed in this laboratory is given, including some instruction on its use. ('14)N NQR data obtained by pulse methods for six classes of nitrogen-containing compounds are presented and analyzed in the framework of the Townes and Dailey theory. A study of the anti-cancer drugs cyclophosphamide, isophosphamide and triphosphamide suggests the existence of a correlation between the substance's chemotherapeutic efficacy and the (pi) - (sigma)(,NP) charge density at the trigonal nitrogen. Satisfactory correlations of the NQR spectra of 22 monosubstituted anilines with both the Hammett (sigma) parameters and the in vitro biological activities of the corresponding sulfanilamides have been found, indicating that the nitrogen lone-pair orbital is more sensitive than the nitrogen-carbon sigma orbital is to substituent effects. NQR spectra of several N-acetyl amino acids and related compounds are reported. The inductive effect of the chloroacetyl group on the nitrogen is discussed. A positive correlation between the (pi) - (sigma)(,NC) electron density at the nitrogen and the Taft inductive parameter (sigma)* is observed, suggesting that the nitrogen (pi) -charge density in the N-acetyl amino acids does not vary appreciably. Both ('14)N and ('35)Cl NQR data have been obtained for a series of compounds containing nitrogen directly bonded to chlorine. The existence of a linear correlation between the ('14)N and ('35)Cl quadrupole coupling constants is interpreted in terms of a simple model dealing with charge excesses and deficiencies at the respective nuclei. A study of two complexes of 4-aminopyridine (4AP) addresses the loss of pyridine nitrogen lone-pair charge upon formation of the strong and asymmetric N-H-N bond characteristic of these complexes. Evidence of hydrogen bonding interactions involving the amino nitrogens is found to be in agreement with a published neutron diffraction study. ('14)N NQR data for seven organic dye cations and one free base are presented. The cations are weakly paramagnetic at 77 K, exhibiting broad and featureless EPR spectra characteristic of weak charge-transfer complexes. The positive charge in the cations is largely delocalized. The existence of a simple relationship between the ('14)N NQR data and optical properties for three cyanine laser dyes is discussed.

Greenbaum, Steven Garry

73

NMR and NQR studies of the heavy fermion superconductors CeTIn{sub 5} (T=Co and Ir)  

SciTech Connect

We have carried out {sup 115}In and {sup 59}Co nuclear quadrupole resonance and nuclear magnetic resonance measurements on CeCoIn{sub 5} and CeIrIn{sub 5}. The temperature T dependence of the nuclear spin-lattice relaxation rate 1/T{sub 1} of {sup 115}In in the normal state indicates that CeCoIn{sub 5} is located just at an antiferromagnetic instability, and CeIrIn{sub 5} is in the nearly antiferromagnetic region. In the superconducting state, 1/T{sub 1} has no Hebel-Slichter coherence peak just below T{sub C} and a power-law T dependence (close to T{sup 3}) at very low temperatures, which indicates the existence of line nodes in the superconducting energy gap. The {sup 115}In (Ce-In plane) Knight shift in CeCoIn{sub 5} decreases for both parallel and perpendicular directions to the tetragonal c axis in the superconducting state, which shows that the spin susceptibility decreases in all directions. These results indicate that CeCoIn{sub 5} and CeIrIn{sub 5} exhibit non-s-wave even parity (probably d-wave) superconductivity.

Kohori, Y.; Yamato, Y.; Iwamoto, Y.; Kohara, T.; Bauer, E. D.; Maple, M. B.; Sarrao, J. L.

2001-10-01

74

NQR investigation of pressure-induced charge transfer in oxygen-deficient YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} ({delta} = 0.38)  

SciTech Connect

Measurements of the pressure dependence of {sup 63}Cu nuclear quadrupole frequency in YBa{sub 2}Cu{sub 3}O{sub 6.62} from ambient pressure up to 1.5 GPa at 4k have been performed. {Tc} was found to increase with pressure: d{Tc}/dp {approximately} 5 K/GPa. All observed NQR lines are linear in pressure: dln{nu}{sub Q}/dp=z. We found positive z for the empty chain sites, consistent with ionic (Cu{sup 1+}) configuration in which the atom simply feels a squeezing lattice. Planar coppers close to the empty chains have positive z, while those that are close to full chains have z {approximately} 0. We present an analysis of the NQR result on the basis of the charge transfer model in which the mobile charges migrate from the chain to the plane sites. We deduced that a transfer of 0.021 holes to the O(2,3) sites would explain the result in YBa{sub 2}Cu{sub 3}O{sub 6.62}, whereas only 0.007 holes transfer in fully oxygenated YBa{sub 2}Cu{sub 3}O{sub 7}.

Reyes, A.P.; Ahrens, E.T.; Hammel, P.C.; Heffner, R.H. [Los Alamos National Lab., NM (United States); Takigawa, M. [International Business Machines Corp., Yorktown Heights, NY (United States). Thomas J. Watson Research Center

1992-03-01

75

Zero field NMR and NQR  

SciTech Connect

Methods are described and demonstrated for detecting the coherent evolution of nuclear spin observables in zero magnetic field with the full sensitivity of high field NMR. The principle motivation is to provide a means of obtaining solid state spectra of the magnetic dipole and electric quadrupole interactions of disordered systems without the line broadening associated with random orientation with respect to the applied magnetic field. Comparison is made to previous frequency domain and high field methods. A general density operator formalism is given for the experiments where the evolution period is initiated by a sudden switching to zero field and is terminated by a sudden restoration of the field. Analytical expressions for the signals are given for a variety of simple dipolar and quadrupolar systems and numerical simulations are reported for up to six coupled spin-1/2 nuclei. Experimental results are reported or reviewed for /sup 1/H, /sup 2/D, /sup 7/Li, /sup 13/C, and /sup 27/Al nuclei in a variety of polycrystalline materials. The effects of molecular motion and bodily sample rotation are described. Various extensions of the method are discussed, including demagnetized initial conditions and correlation by two-dimensional Fourier transformation of zero field spectra with themselves or with high field spectra.

Zax, D.B.; Bielecki, A.; Zilm, K.W.; Pines, A.; Weitekamp, D.P.

1985-11-15

76

59Co, 23Na, and 1H NMR Studies of Double-Layer Hydrated Superconductors NaxCoO2 · yH2O  

NASA Astrophysics Data System (ADS)

We present our NMR studies of double-layer hydrated cobalt oxides NaxCoO2 · yH2O (x ? 0.35, y ? 1.3) with various T c = 0-4.8K and magnetic transition temperatures. High-resolution 1H NMR spectrum served as an evidence for the existence of H3O+ oxonium ions. 23Na nuclear spin-lattice relaxation rates served to detect local field fluctuations sensitive to T c. 59Co nuclear quadrupole resonance (NQR) spectra served to classify the various T c samples. From the classification by 59Co NQR frequency, the double-layer hydrated compounds were found to have two superconducting phases closely located to a magnetic phase. In the normal state and at a magnetic field in the ab-plane, two 59Co NMR signals with different Knight shifts and different 59Co nuclear spin-lattice relaxation times 59 T 1 were observed. The two 59Co NMR signals suggest magnetic disproportionation of two Co sites or XY-anisotropy of a single Co site. Non Korringa behavior and power law behavior in zero-field NQR 1/59 T 1 above and below T c suggest non-Fermi liquid and unconventional superconductivity.

Itoh, Y.; Ohta, H.; Michioka, C.; Kato, M.; Yoshimura, K.

77

Local distortions in the BiO6-octahedra sublattice of BaPbxBi1-xO3 as seen by a137Ba NMR/NQR  

NASA Astrophysics Data System (ADS)

The a137Ba NMR and NQR spectra as well as the spin-lattice relaxation rate were measured for the first time in the BaPbxBi1-xO3 samples with x = 0.91 (normal metal), x = 0.75 (superconductor) and x = 0.64 (semiconductor). The strong quadrupole broadening of the NMR lines with lowering temperature was found for all the samples. An evolution of static distortions in the BiO6-octahedra sublattice along with asymmetry of the electric field gradient at the Ba-sites is discussed. This asymmetry caused by the nearest non-cubic surrounding of barium is originated from the temperature dependent tilt of BiO6-octahedra. Spin-lattice relaxation rate of a137Ba is monitored by fluctuating part of electric field gradient at the Ba-site and its exponential growth at low temperatures evidences the thermally activated collective rotations of BiO6-octahedra around their static tilt. An activation energy and a strength of these dynamic distortions are evaluated and found to increase in going from metallic to semiconducting phase of BaPbxBi1-xO3.

Verkhovskii, S. V.; Gerashenko, A. P.; Zhdanov, Yu. I.; Mikhalev, K. N.; Sagaradze, I. V.; Medvedev, Eu. Yu.; Cheshnitskii, S. M.; Pletnev, R. N.; Kumagai, K.; Piskunov, Yu. V.; Yakubovskii, A. Yu.

1997-02-01

78

Cl-NQR study of the structural order-disorder transition in (CH3NH3)2MnCl4  

Microsoft Academic Search

The temperature dependence of the Cl nuclear quadrupole resonance for the two chemically inequivalent chlorine sites in the perovskitic layer structure compound (CH3NH3)2 MnCl4 has been measured around the second order phase transition at 393.7 K. A value of the critical exponent ? of the order parameter was determined to be ? = 0.250 ± 0.005 which is intermediate between

R. Kind; J. Roos

1976-01-01

79

Enhanced spin fluctuations in the As-based filled skutterudite LaFe4As12 : A L139a NMR and A75s NQR study  

NASA Astrophysics Data System (ADS)

We have grown single crystals of the itinerant-electron weak ferromagnet LaFe4As12 (TC=3.8K) and refined its crystal structure parameters. We report experimental results of magnetic susceptibility and nuclear magnetic resonance at the La site and nuclear quadrupole resonance at the As site in the paramagnetic state for this compound. The temperature dependences of the static magnetic susceptibility, the L139a Knight shift, and the reciprocal of the product of the spin-lattice relaxation time and temperature (1/T1T) of both L139a and A75s nuclei can be consistently understood in terms of self-consistent renormalization theory of spin fluctuations for weak itinerant-electron ferromagnets.

Nowak, B.; ?oga?, O.; Pietraszko, A.; Baumbach, R. E.; Maple, M. B.; Henkie, Z.

2009-06-01

80

19 Cl NQR study of the fluorine effect of the aryl substituent on the element-chlorine bond in compounds of subgroup V and VI elements  

Microsoft Academic Search

UDC 541.49 Due to the introduction of fluorine atoms into the benzene ring, the accepting effect of the pentafluorophenyl group is higher than that of the phenyl one, this increases the electronegativity of the element of the functional group directly bonded to the group. In compounds in which the given element of the functional group is directly bonded to the

O. Kh. Poleshchuk; G. G. Furin; I. Latoszinska

1997-01-01

81

NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts. Quarterly technical progress report, December 15, 1991--March 15, 1992  

SciTech Connect

During this period, we focused our attention in analyzing the magnetic nature of the extensively used trimetallic catalyst system Cu-Co-Cr for the production of higher alcohols. We believe that there could be some correspondence between the catalytic and magnetic behaviors of the transition metal catalyst systems. Both the morphology and metallic charge distribution of the particles are know to govern the catalytic as well as the magnetic properties of the system. Based on this concept, we have extensively examined the Cu/Co system varying Cu/Co ratio from 0.2--4.0. Spectroscopic results are outlined herein. (VC)

Not Available

1992-04-15

82

NMR Studies of the Normal State of High Temperature Superconductors  

NASA Astrophysics Data System (ADS)

We review NMR and NQR studies in the normal state of high-T_c superconducting cuprates. Emphasis is given on the three major contributions brought by these techniques: the presence of antiferromagnetic fluctuations, the possible justification of a single spin fluid model, and the opening of a pseudogap in the spin excitations for underdoped compounds. Some recent developments are addressed and compared to theoretical models. In particular, quantitative analysis of the nuclear relaxation are detailed for ^{63}Cu, ^{89}Cu, ^{17}O nuclei, enabling a comparison with inelastic neutron scattering data, and finally pointing out to a serious difficulty with the one-band approach.

Berthier, C.; Julien, M. H.; Horvati?, M.; Berthier, Y.

1996-12-01

83

35Cl quadrupole resonance study of the thermally activated motion of the nitro group in chlorinated nitrobenzenes  

NASA Astrophysics Data System (ADS)

The results of NQR studies of the thermoactivated motion of NO2 groups in chlorine-containing nitrobenzenes are presented. A procedure for analyzing the experimental data is suggested. It uses the characteristic temperature of the minimum of the modulation contribution to the temperature dependence of the spin-lattice relaxation time T 1 of the resonant probe nuclei (35Cl) bonded with the moving group by nonvalent interactions. The activation energy of the thermoactivated motion was correlated with the temperature of the minimum. The possibility of a temperature dependence of the activation energy of the NO2 group was examined.

Kyuntsel, I. A.

2013-05-01

84

Investigation of H-bonding and halogen-bonding effects in dichloroacetic acid: DFT calculations of NQR parameters and QTAIM analysis.  

PubMed

A theoretical study was performed to examine hydrogen and halogen bonds properties in gas phase and crystalline dichloroacetic acid (DCAA). The specific pattern of O-H???O, C-H???O, HCl, Cl???O and Cl???Cl interactions in DCAA dimers is described within the quantum theory of atoms in molecules (QTAIM) formalism. Based on QTAIM results, a partial covalent character is attributed to the O-H???O hydrogen bonds in DCAA, whereas all the C-H???O, Cl···O and Cl???Cl intermolecular interactions are weak and basically electrostatic in nature. MP2/6-311++G** calculations indicate that the interaction energies for DCAA dimers lie in the range between -0.40 and -14.58 kcal mol(-1). One of the most important results of this study is that, according to energy decomposition analyses, halogen bonds are largely dependent on both electrostatic and dispersion interactions. For those nuclei participating in the hydrogen-bonding and halogen-bonding interactions, nuclear quadrupole coupling constants exhibit significant changes on going from the isolated molecule model to the crystalline DCAA. Of course, the magnitude of these changes at each nucleus depends directly on its amount of contribution to the interactions. PMID:22736221

Esrafili, Mehdi D

2012-06-27

85

Nuclear Quadrupole Resonance Studies of the Sorc Sequence and Nuclear Magnetic Resonance Studies of Polymers.  

NASA Astrophysics Data System (ADS)

The behavior of induction signals during steady -state pulse irradiation in ^{14} N NQR was investigated experimentally. Because Strong Off-resonance Comb (SORC) signals recur as long as the pulsing continues, very efficient signal-averaging can result. The dependence of these steady-state SORC signals on pulse parameters and on frequency offset are presented, together with a discussion of the applicability of the method. Also as part of the NQR work, Cocaine base has been detected using conventional NQR techniques. The experimental results show that SORC detection can be of sufficient sensitivity to form the basis of narcotics screening devices for both mail and airline baggage. A new NMR technique, to obtain the correlation time of the random thermal motion of a polymer at temperatures near the glass transition has been introduced. The temperature dependence is a result of thermal motion. For slow-motion of a polymer chain near the glass transition, the CSA parameter begins to decrease. This motional narrowing can be interpreted to yield the correlation time of the thermal motion. In this work Nitrocellulose isotopically highly enriched with ^{15}N was studied at four different temperatures between 27^ circ and 120^circ Celsius and the correlation times for polymer backbone motions were obtained. Nafion films containing, water (D_2 O and H_2^{17}O) and methanol (CH_3OD, CH _3^{17}OH), have been studied using Deuteron and Oxygen-17 NMR spectroscopy. Glassy behavior of the water domains at low temperature is evidenced by the specific nature of the ^2H NMR lineshapes. Activation energies extracted from ^2H spin-lattice relaxation data on the high temperature side of the T_1 minimum exhibit a steady increase with increasing water content. In spite of a high degree of molecular mobility, angular-dependent spectra of both unstretched and stretched samples reflect considerable anisotropy of the host polymer. Activation volumes corresponding to a specific dynamical process were obtained from measurements of spin-lattice relaxation vs. pressure. From the NMR measurements of Nafion films containing methanol, it was found that the molecular motion is much more rapid than the molecular motion of water in Nafion membranes.

Jayakody, Jayakody R. Pemadasa

1993-01-01

86

Utilization of pure nuclear quadrupole resonance spectroscopy for the study of pharmaceutical crystal forms.  

PubMed

Solid-state physical characterization of a pharmaceutical substance is necessary for successful development and approval of the final product. Different physical analytical techniques are available to do so: X-ray diffraction (XRD), IR, Raman, DSC, TG and NMR. Moreover, all of them detect the presence of excipients perturbing the analysis of the pure substance in low doses. In order to study polymorphism and pseudo polymorphism of drug, this paper introduces possible applications of pure nuclear quadrupole resonance, as a non-destructive technique in qualitative and quantitative approaches. Chlorpropamide and diclofenac sodium were used as examples. Unlike the mentioned techniques, the nuclear quadrupole resonance (NQR) signal of pharmaceutical compounds is not perturbed by the presence of solid excipient or other substances unless they possess resonance frequencies in the same frequency range of the compound studied. PMID:15913931

Pérez, S C; Cerioni, L; Wolfenson, A E; Faudone, S; Cuffini, S L

2005-07-14

87

B 24 N 24 nanocages: a GIAO density functional theory study of 14 N and 11 B nuclear magnetic shielding and electric field gradient tensors  

Microsoft Academic Search

\\u000a Abstract  Density functional theory (DFT) calculations were performed to determine boron-11 and nitrogen-14 nuclear magnetic resonance\\u000a (NMR) and nuclear quadrupole resonance (NQR) spectroscopy parameters in the three most stable B24N24 fullerenes for the first time. The considered samples were first allowed to relax entirely, and then the NMR and NQR calculations\\u000a were performed on the geometrically optimized models. The calculations of

Goudarz Mohseni Rouzbehani; Asadollah Boshra; Ahmad Seif

2009-01-01

88

Inhibitor studies of a new antibiotic, korormicin, 2-n-heptyl-4-hydroxyquinoline N-oxide and Ag+ toward the Na+-translocating NADH-quinone reductase from the marine Vibrio alginolyticus.  

PubMed

A new antibiotic, korormicin, isolated from a marine bacterium Pseudoalteromonas sp. F-420, was found to strongly inhibit the respiratory chain-linked Na+-translocating NADH-quinone reductase (NQR) from the marine Vibrio alginolyticus. Similar to 2-n-heptyl-4-hydroxyquinoline N-oxide (HQNO), korormicin specifically inhibited the Na+-dependent reaction in the NQR complex that is directly coupled to the extrusion of Na+ from the cells. Both korormicin and HQNO acted as purely noncompetitive inhibitors with regard to Q-1, and the inhibitor constants were estimated to be 82 pM and 0.3 microM, respectively. Mutual exclusiveness of korormicin and HQNO was analyzed by kinetic methods, which indicated that a part of the binding site of korormicin and HQNO overlapped, preventing a simultaneous binding of the two inhibitors to the NQR complex. The site of Ag+ inhibition was the initial reaction of the NQR complex catalyzed by Nqr6 subunit. The time courses of Ag+ inhibition and the release of FAD indicate that the Ag+-denatured Nqr6 subunit gradually releases FAD. PMID:10549856

Nakayama, Y; Hayashi, M; Yoshikawa, K; Mochida, K; Unemoto, T

1999-10-01

89

Spin-echoes in nitrogen-14 quadrupolar spin-system with axially symmetric electric field gradient tensor  

Microsoft Academic Search

The behaviour of the magnetisation in the spin-1 system with the axial symmetry of the electric field gradient (EFG) tensor was analysed theoretically. The behaviour of the NQR signals in hexamethylenetetramine (C6H12N4) was also studied experimentally using the pulse NQR technique and sensitive equipment. It was shown that the axial symmetry of the EFG in a sample could not be

T. N. Rudakov; V. T. Mikhaltsevitch; J. H. Flexman

2004-01-01

90

Phase diagram for the spin pseudogap in LaBa{sub 2}Cu{sub 3}O{sub y} studied by NMR  

SciTech Connect

The carrier concentration dependence of the spin pseudogap phenomenon in LaBa{sub 2}Cu{sub 3}O{sub y} has been studied by means of the NMR/NQR method. From the T dependence of 1/T{sub 1}T of the planar Cu site, it has turned out that the characteristic temperature for the spin pseudogap at the staggered mode is a monotonic function of hole concentration in the lightly doped region. However, a spin-gap-like behavior was observed even in the optimally doped sample (y=6.96), where the maximal superconducting transition temperature (T{sub c}) is realized as a function of hole doping. This feature is quite different from that in YBa{sub 2}Cu{sub 3}O{sub y}, where the spin pseudogap is restricted to the lightly doped region and is not observed in the optimally doped sample (y=6.98). Together with 1/T{sub 2G} and Knight shift data, the nature of the gap is discussed. {copyright} {ital 1997} {ital The American Physical Society}

Goto, A.; Yasuoka, H.; Otzschi, K.; Ueda, Y. [Institute for Solid State Physics, University of Tokyo, Roppongi, Minato-ku, Tokyo 106 (Japan)

1997-05-01

91

Inelastic and quasielastic neutron scattering study of the reorientational motions in the layer-type compound {  

NASA Astrophysics Data System (ADS)

Incoherent inelastic scattering (INS) and quasielastic neutron scattering (QNS) experiments on polycrystalline derivatives of the propylenediammonium manganese tetrachloride compound, namely |NH3(CH2)3NH3| MnCl4, |NH3(CD2)3NH3|MnCl4 and |ND3(CH2)3ND3|MnCl4, have been performed over the 100-500 K temperature range, i.e. under three different structural phases. A detailed assignment of the INS spectra is proposed and we observe in particular a pronounced frequency softening of the torsional ?(NH3) vibration in conjunction with an intensity enhancement when the temperature increases; this suggests quite different dynamical regimes for the NH3 groups in the disordered phases. In fact, QNS spectra of the three derivatives under study have been satisfactorily fitted using the following models: ((i) 90° jumps of only the N-H protons over two equivalent positions in the room temperature phase (˜ 100°) and C-H protons (˜ 110°) in the intermediate phase II, the flipping motion of the (CH2)3 backbone occurring among two positions with distinct occupation probabilities (?/3 uniaxial reorientations of the NH3 groups in the high temperature phase I (?HII/RT) and ?HI/RT), where ?HII = 6·9 kJ mol-1 and ?HI = 10·1 kJ mol-1. In addition, 2?/3 reorientations of the NH3 groups in phase I satisfy the equation ?H'IRT) with ?H'I = 8·2 kJ mol-1; the latter activation energy is significantly lower than the potential barrier for the torsional motion as deduced from the INS torsional frequency, V3 ?~ 11·0 kJ mol-1 (493 K). We present a comparison with other data, from optical, deuteron-N.M.R., and N.Q.R. results, and the dynamical mechanisms in the different structural forms are discussed.

Sourisseau, Claude; Guillaume, François; Lucazeau, Guy; Dianoux, Albert-José

92

Heavy Fermion Superconductor Ce2PdIn8 studied by 115In Nuclear Quadrupole Resonance  

NASA Astrophysics Data System (ADS)

We have performed nuclear quadrupole resonance (NQR) measurements on a recently-discovered heavy-fermion superconductor Ce2PdIn8 with superconducting critical temperature Tc = 0.64 K. Below coherent temperature Tcoh ~ 30 K, the spin-lattice relaxation rate 1/T1 decreases with decreasing temperature T and is proportional to T1/2 between Tc and Tcoh. This is clearly different from the Fermi-liquid behavior in which the T dependence is proportional to T, and indicates that Ce2PdIn8 is located on the verge of antiferromagnetic quantum critical point from the view point of the NQR. Below Tc, 1/T1 shows no coherence peak and is proportional to T3. This is clear evidence for the realization of unconventional superconductivity with line nodes in this compound.

Fukazawa, H.; Nagashima, R.; Shimatani, S.; Kohori, Y.; Kaczorowski, D.

2013-07-01

93

DFT Study of HFI in Halogen-Containing Gold, Silver and Copper Complexes  

Microsoft Academic Search

We have analyzed the nuclear quadrupole coupling constants in copper, silver and gold halides and related compounds an the\\u000a basis of the calculations with use of pseudo-potentials. The geometrical parameters and NQR halogen quadrupole constants obtained\\u000a by these calculations substantially corresponded to the data of microwave spectroscopy in the gas phase. The analysis of the\\u000a quality of the calculations with

O. K. Poleshchuk; E. L. Shevchenko; V. Branchadell; A. Schulz; B. Nogaj; B. Brycki

2004-01-01

94

Radio-frequency tunable atomic magnetometer for detection of solid-state NQR  

Microsoft Academic Search

We constructed a potassium atomic magnetometer which resonantly detects rf magnetic fields with subfemtotesla sensitivity. The resonance frequency is set by the Zeeman resonance of the potassium atoms in a static magnetic field applied to the magnetometer cell. Strong optical pumping of the potassium atoms into a stretched state reduces spin-exchange broadening of the Zeeman resonance, resulting in relatively small

S.-K. Lee; K. L. Sauer; S. J. Seltzer; O. Alem; M. V. Romalis

2007-01-01

95

Using nitrogen-14 nuclear quadrupole resonance and electric field gradient information for the study of radiation effects  

SciTech Connect

Nitrogen-14 nuclear quadrupole resonance (NQR) was used in an attempt to detect the effects of ionizing radiation on organic material. Previously reported resonances for urea were detected at 2,913.32 {+-} 0.01 kHz and 2,347.88 {+-} 0.08 kHz with associated T{sub 2}* values 780 {+-} 20 {micro}s and 523 {+-} 24 {micro}s, respectively. The previously unreported {nu}{sub {minus}} line for urea-d{sup 4} was detected at 2,381 {+-} 0.04 Khz and used to determine accurately for the first time the values for the nuclear quadrupole coupling constant {chi} (3,548.74 {+-} 0.03 kHz) and the asymmetry parameter {eta} (0.31571 {+-} 0.00007) for urea-d{sup 4}. The inverse linewidth parameter T{sub 2}* for {nu}{sub +} was measured at 928 {+-} 23 {micro}s and for {nu}{sub {minus}} at 721 {+-} 12 {micro}s. Townes and Dailey analysis was performed and urea-d{sup 4} exhibits a 0.004 increase in lone pair electronic density and a slight decrease in N-H bond electronic density, as compared to urea, probably due to the mass difference. A relationship is proposed, referred to as NQR linewidth analysis, between the dynamic spin relaxation times T{sub 2} and T{sub 2}* and the widths of the distributions of the NQR parameters. Linewidth analysis is presented as a tool for possible use in future NQR work in all area, not just radiation effects. This relationship is tested using sodium nitrite T{sub 2} and T{sub 2}* values for {nu}{sub {minus}} and {nu}{sub {minus}} as a function of temperature.

Iselin, L.H.

1995-12-01

96

A theoretical study of 17O, 14N and 2H nuclear quadrupole coupling tensors in the real crystalline structure of acetaminophen  

NASA Astrophysics Data System (ADS)

A systematic computational investigation was carried out to characterize the 17O, 14N and 2H electric field gradient, EFG, tensors in the acetaminophen real crystalline structure. To include the hydrogen bonding effects in the calculations, the most probable interacting molecules with the target molecule in the crystalline phase were considered through the various molecular clusters. The calculations were performed with the B3LYP method and 6-311++G?? and 6-311+G? standard basis sets using the Gaussian 98 suite of programs. Calculated EFG tensors were used to evaluate the 17O, 14N, and 2H nuclear quadrupole resonance, NQR, parameters in acetaminophen crystalline structure, which are in good agreement with the available experimental data. The difference between the calculated NQR parameters of the monomer and molecular clusters shows how much hydrogen bonding interactions affect the EFG tensors of each nucleus. These results indicate that both O H?O and N H?O hydrogen bonding have major influence on the NQR parameters. Moreover, the quantum chemical calculation indicated that the intermolecular hydrogen bonding interactions play an essential role in determining the relative orientation of quadrupole coupling principal components in the molecular frame axes.

Behzadi, Hadi; Esrafili, Mehdi D.; Hadipour, Nasser L.

2007-03-01

97

Low-frequency nuclear quadrupole resonance with a dc SQUID  

SciTech Connect

Conventional pure nuclear quadrupole resonance (NQR) is a technique well suited for the study of very large quadrupolar interactions. Numerous nuclear magnetic resonance (NMR) techniques have been developed for the study of smaller quadrupolar interactions. However, there are many nuclei which have quadrupolar interactions of intermediate strength. Quadrupolar interactions in this region have traditionally been difficult or unfeasible to detect. This work describes the development and application of a SQUID NQR technique which is capable of measuring intermediate strength quadrupolar interactions, in the range of a few hundred kilohertz to several megahertz. In this technique, a dc SQUID (Superconducting QUantum Interference Device) is used to monitor the longitudinal sample magnetization, as opposed to the transverse magnetization, as a rf field is swept in frequency. This allows the detection of low-frequency nuclear quadrupole resonances over a very wide frequency range with high sensitivity. The theory of this NQR technique is discussed and a description of the dc SQUID system is given. In the following chapters, the spectrometer is discussed along with its application to the study of samples containing half-odd-integer spin quadrupolar nuclei, in particular boron-11 and aluminum-27. The feasibility of applying this NQR technique in the study of samples containing integer spin nuclei is discussed in the last chapter. 140 refs., 46 figs., 6 tabs.

Chang, J.W.

1991-07-01

98

Microscopic magnetic nature of water absorbed Na0.35CoO2 investigated by NMR, NQR and ?+SR  

NASA Astrophysics Data System (ADS)

In order to clarify the variation of the microscopic magnetic nature with the carrier density in NaxCoO2·yHO, we have measured positive muon-spin rotation/relaxation (?+SR) spectra for H2O as well as D2O absorbed samples. Based on the zero field (ZF-) ?+SR measurements, there was no clear difference between the two superconducting phases (SC-I and SC-II). Furthermore, the ZF-spectrum for the H2O absorbed sample exhibits a clear oscillation in the whole T range measured (1.4-100 K), suggesting the formation of “[H3O]+-like” H2?+O ions in the sample. Further, the absence of an oscillation in the D2O absorbed sample also evidences the presence of H2?+O. We also measured 59Co nuclear quadrupole resonance spectra of magnetic sample. The temperature dependence of spectra shows that there is no evidence of charge ordering and CDW ordering around magnetic transition temperature.

Ohta, Hiroto; Månsson, Martin; Ikedo, Yutaka; Sugiyama, Jun; Michioka, Chishiro; Yoshimura, Kazuyoshi; Brewer, Jess H.; Ansaldo, Eduardo J.; Stubbs, Scott L.; Chow, Kim H.; Lord, James S.

2010-12-01

99

209Bi NMR and NQR investigation of the small-gap semiconductor Ce3Bi4Pt3  

Microsoft Academic Search

We report measurements of the temperature dependence of the 209Bi nuclear quadrupole resonance frequency nuQ, the Knight shift K, and the spin-lattice relaxation rate 1\\/T1 in the small-gap semiconductor Ce3Bi4Pt3 between 1.8 and 300 K. Corresponding measurements also are reported for the nonmagnetic metallic isomorph La3Bi4Pt3. The nuQ data in the Ce compound show a characteristic departure from metallic-to-insulating behavior

A. P. Reyes; R. H. Heffner; P. C. Canfield; J. D. Thompson; Z. Fisk

1994-01-01

100

209Bi NMR and NQR investigation of the small-gap semiconductor Ce3Bi4Pt3  

NASA Astrophysics Data System (ADS)

We report measurements of the temperature dependence of the 209Bi nuclear quadrupole resonance frequency ?Q, the Knight shift K, and the spin-lattice relaxation rate 1/T1 in the small-gap semiconductor Ce3Bi4Pt3 between 1.8 and 300 K. Corresponding measurements also are reported for the nonmagnetic metallic isomorph La3Bi4Pt3. The ?Q data in the Ce compound show a characteristic departure from metallic-to-insulating behavior when the sample is cooled below TM=80 K, the temperature of the susceptibility maximum, attributable to a loss of low-frequency vibrational modes in the insulating state. The Knight shift has both isotropic and axial components; this anisotropy originates from the presence of Ce via a transferred hyperfine coupling between Ce 4f and conduction electrons. An s-f exchange constant >=0.4 eV is found, consistent with hybridization in other rare-earth intermetallic compounds. A change in the scaling between the susceptibility and both the isotropic and axial Knight shifts at temperature TM provides evidence that hybridization between the Ce 4f orbitals and the conduction electrons is responsible for the gap structure. The temperature dependence of the 1/T1 data is consistent with a model electronic density of states possessing a temperature-independent gap ? of 180 K and a bandwidth of the order of 1600 K. The temperature dependence of 1/T1 can also be fit well with a temperature-dependent gap with ?(0) also ~=180 K.

Reyes, A. P.; Heffner, R. H.; Canfield, P. C.; Thompson, J. D.; Fisk, Z.

1994-06-01

101

Determination of the sign of the electric field gradient in indium by nuclear resonance  

SciTech Connect

The authors have studied the temperature dependence of two of the four magnetic-field perturbed NQR lines in indium. Their results indicate that the sign of the internal electric field gradient (EFG) is positive, in accord with the recent heat capacity measurements of the ISSP group and one recent theoretical prediction. They also discuss the implications of the sign of the EFG on the use of indium as an absolute thermometer below 1 mK.

Pollack, L.; Smith, E.N.; Richardson, R.C. [Cornell Univ., Ithaca, NY (United States)

1997-01-01

102

Detection of ammonium nitrate inside vehicles by nuclear quadrupole resonance  

Microsoft Academic Search

The development of a system for the detection of ammonium nitrate (AN) in vehicles by nuclear quadrupole resonance (NQR) is\\u000a described. The results from studies of the penetration of radiofrequency (RF) magnetic fields inside certain metal enclosures,\\u000a including full-scale vehicles, were critical in the design of a novel high-Q resonant probe. The probe was shaped not only for optimal penetration

J. Barras; M. J. Gaskell; N. Hunt; R. I. Jenkinson; K. R. Mann; D. A. G. Pedder; G. N. Shilstone; J. A. S. Smith

2004-01-01

103

Mutual Orientations of the Principal Axes of the Electric-Field Gradient Tensors on 14N and 81Br by Combined Zeeman-Effect Measurements in a Single Crystal of p-Bromoaniline  

Microsoft Academic Search

The Zeeman effect of the nuclear quadrupole resonance of both 14N and 81Br nuclei in a single crystal of p-bromoaniline was studied. The precision of the technique used here is far greater than that of the few previous works in this field. Measurements were made by means of a newly designed spectrometer, working at both 14N and 81Br NQR frequencies,

A. Colligiani; R. Ambrosetti; P. Cecchi

1971-01-01

104

Local Cu and Br environments and their relationship to superconductivity restoration in brominated YBa{sub 2}Cu{sub 3}O{sub y}  

SciTech Connect

{sup 63,65}Cu nuclear quadrupole resonance (NQR) and Br {ital k}-edge x-ray absorption fine structure (XAFS) have been used to study the local structures in well-characterized samples of deoxygenated and brominated YBa{sub 2}Cu{sub 3}O{sub y}(YBCO). NQR shows that after bromination of YBa{sub 2}Cu{sub 3}O{sub 6.1} at 260thinsp{degree}C, oxygen has repopulated the chain sites. From XAFS, it is concluded that Br does not enter the YBCO lattice, but rather precipitates out as small nanoscale particles of BaBr{sub 2}. These results provide clear evidence of the role of Br in reoxygenating the YBCO structure and an explanation for the partial restoration of superconductivity in the YBCO system. {copyright} {ital 1998 American Institute of Physics.}

Potrepka, D.M.; Fenner, D.B.; Balasubramanian, M.; Hines, W.A.; Budnick, J.I. [Department of Physics and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States)

1998-08-01

105

A dual role for plant quinone reductases in host-fungus interaction.  

PubMed

Quinone reductases (QR, EC 1.5.6.2) are flavoproteins that protect organisms from oxidative stress. The function of plant QRs has not as yet been addressed in vivo despite biochemical evidence for their involvement in redox reactions. Here, using knock-out (KO) and overexpressing lines, we studied the protective role of two groups of Arabidopsis thaliana cytosolic QRs, Nqr (NAD(P)H:quinone oxidoreductase) and Fqr (flavodoxin-like quinone reductase), in response to infection by necrotrophic fungi. The KO lines nqr(-) and fqr1(-) displayed significantly slower development of lesions of Botrytis cinerea and Sclerotinia sclerotium in comparison to the wild type (WT). Consistent with this observation, the overexpressing line FQR1(+) was hypersensitive to the pathogens. Both the nqr(-) and fqr1(-) displayed increased fluorescence of 2',7'-dichlorofluorescein,? a reporter for reactive oxygen species in response to B. cinerea. Infection by B. cinerea was accompanied with increased Nqr and Fqr1 protein levels in the WT as revealed by western blotting. In addition, a marked stimulation of salicylic acid-sensitive transcripts and suppression of jasmonate-sensitive transcripts was observed in moderately wounded QR KO mutant leaves, a condition mimicking the early stage of infection. In contrast to the above observations, germination of conidia was accelerated on leaves of QR KO mutants in comparison with the WT and FQR1(+) . The same effect was observed in water-soluble leaf surface extracts. It is proposed that the altered interaction between B. cinerea and the QR mutants is a consequence of subtly altered redox state of the host, which perturbs host gene expression in response to environmental stress such as fungal growth.?????? PMID:23464356

Heyno, Eiri; Alkan, Noam; Fluhr, Robert

2013-04-02

106

Nuclear spin-lattice relaxation-time reduction in small particles  

NASA Astrophysics Data System (ADS)

A method is described of reducing the nuclear spin-lattice relaxation time in a polycrystalline solid without the introduction of any paramagnetic impurities. It relies on the fact that the relaxation times of nuclei on a surface are usually much shorter than those in the bulk due to greater freedom of movement. Simply reducing the particle size by grinding or other methods is shown to be effective in markedly reducing the spin-lattice relaxation time of all the nuclei in the specimen because of the good thermal contact between like nuclei in the interior and surface of small particles. The nuclear quadrupole resonance (NQR) of 14N, 2D, or 23Na was measured for the same specimens with different particle sizes by nuclear quadrupole double resonance to ensure that the chemical structure of the compound did not alter due to the grinding. In all samples studied, except sodium thiosulphate, the NQR spectrum was unaffected by the grinding except that the time necessary to collect the data was reduced. In the case of sodium thiosulphate a marked change in the NQR spectrum was observed despite the fact that no change in chemical composition could be detected. Data is presented which demonstrates the effectiveness of the technique and a simple model of the underlying mechanism is described.

Rabbani, S. R.; Edmonds, D. T.

1994-09-01

107

INSTRUMENTS AND METHODS OF INVESTIGATION: New technologies: nuclear quadrupole resonance as an explosive and narcotic detection technique  

NASA Astrophysics Data System (ADS)

Possibilities of detecting nuclear quadrupole resonance (NQR) signals in explosives and drugs are considered. Direct and indirect NQR techniques for searching substances are described and the potentialities of various experimental methods are compared.

Grechishkin, Vadim S.; Sinyavskii, Nikolai Ya

1997-04-01

108

A 14N nuclear quadrupole resonance study of phase transitions and molecular dynamics in hydrogen bonded organic antiferroelectrics 55DMBP-H2ca and 1,5-NPD-H2ca.  

PubMed

The temperature dependence of the (14)N NQR frequencies has been measured in antiferroelectric and paraelectric 55DMBP-H(2)ca and 1,5-NPD-H(2)ca. In both compounds we observe two non-equivalent nitrogen positions (N(+)-H···O(-) and N···H-O) in the antiferroelectric phase. The two nitrogen positions become equivalent (N···H···O) in the paraelectric phase. The critical exponent of the local antiferroelectric order parameter has been determined from the NQR data. The principal values of the quadrupole coupling tensor correlate in both compounds. The correlation diagrams clearly show how a proton migrates from the antiferroelectric position towards the paraelectric position in the bifurcated hydrogen bond on increasing the temperature. A slow motion has been observed in 55DMBP-H(2)ca by the (1)H and (14)N spin-lattice relaxation. An analysis of the spin-lattice relaxation data suggests a slow exchange between two non-planar conformations of the bipyridine molecule. PMID:21483963

Seliger, Janez; Žagar, Veselko; Asaji, Tetsuo; Gotoh, Kazuma; Ishida, Hiroyuki

2011-04-11

109

Covalent binding of flavins to RnfG and RnfD in the Rnf complex from Vibrio cholerae.  

PubMed

Enzymes of the Rnf family are believed to be bacterial redox-driven ion pumps, coupling an oxidoreduction process to the translocation of Na+ across the cell membrane. Here we show for the first time that Rnf is a flavoprotein, with FMN covalently bound to threonine-175 in RnfG and a second flavin bound to threonine-187 in RnfD. Rnf subunits D and G are homologous to subunits B and C of Na+-NQR, respectively. Each of these Na+-NQR subunits includes a conserved S(T)GAT motif, with FMN covalently bound to the final threonine. RnfD and RnfG both contain the same motif, suggesting that they bind flavins in a similar way. In order to investigate this, the genes for RnfD and RnfG from Vibrio cholerae were cloned and expressed individually in that organism. In both cases the produced protein fluoresced under UV illumination on an SDS gel, further indicating the presence of flavin. However, analysis of the mutants RnfG-T175L, RnfD-T278L, and RnfD-T187V showed that RnfG-T175 and RnfD-T187 are the likely flavin ligands. This indicates that, in the case of RnfD, the flavin is bound, not to the SGAT sequence but to the final residues of a TMAT sequence, a novel variant of the flavin binding motif. In the case of RnfG, flavin analysis, followed by MALDI-TOF-TOF mass spectrometry, showed that an FMN is covalently attached to threonine-175, the final threonine of the S(T)GAT sequence. Studies by visible, EPR, and ENDOR spectroscopy showed that, upon partial reduction, the isolated RnfG produces a neutral semiquinone intermediate. The semiquinone species disappeared upon full reduction and was not observed in the denatured protein. A topological analysis combining reporter protein fusion and computer predictions indicated that the flavins in RnfG and RnfD are localized in the periplasmic space. In contrast, in NqrC and NqrB the flavins are located in a cytoplasmic loop. This topological analysis suggests that there may be mechanistic differences between the Rnf and Na+-NQR complexes. PMID:18831535

Backiel, Julianne; Juárez, Oscar; Zagorevski, Dmitri V; Wang, Zhenyu; Nilges, Mark J; Barquera, Blanca

2008-10-02

110

Microscopic study of local structure and charge distribution in metallic La{sub 2}CuO{sub 4+{delta}}  

SciTech Connect

The authors employ NMR and NQR spectroscopy as probes of local structure and charge environments in metallic La{sub 2}CuO{sub 4+{delta}} ({Tc} = 38 K). They discuss the effect of annealing the sample at various temperatures T{sub a} ({Tc} < T{sub a} < 300K) on the superconducting {Tc}. The dependence of {Tc} on annealing indicates that annealing allows the development of structural order which is important for {Tc}. The {sup 139}La quadrupole frequency, {nu}{sub Q} is smaller than in undoped materials. This is unexpected and may indicate a smaller charge on the apex oxygen in the doped material and thus a different distribution of charge between the La-O layer to the planes. The further, rapid decrease in {nu}{sub Q} just above {Tc} indicates that temperature dependent charge redistribution is occurring. The presence of doped holes induces a distribution of displacements of the apex oxygen off of the vertical La-Cu bond axis. These vary from zero to the value observed in lightly doped (antiferromagnetic) La{sub 2}CuO{sub 4+{delta}}. These measurements demonstrate a striking degree of inhomogeneity in the crystal structure of the La-O layer. Copper NQR spectroscopy shows that there are two distinct copper sites in the CuO{sub 2} planes and thus that either the structure or the charge distribution in the planes is inhomogeneous as well. These inhomogeneities are the intrinsic response of the crystal to doped holes; they are not the result of distortions of the lattice due to the presence of interstitial oxygen atoms.

Hammel, P.C.; Reyes, A.P.; Ahrens, E.T.; Fisk, Z.; Canfield, P.C.; Thompson, J.D. [Los Alamos National Lab., NM (United States); Schirber, J.E. [Sandia National Labs., Albuquerque, NM (United States)

1993-10-29

111

Determination of the Parameters of the Electric Field Gradient Tensor for Nuclei with Half Integral Spin from Zeeman-Split NQR Spectra  

Microsoft Academic Search

A new method is proposed for determining the magnitude of the coupling constant, the asymmetry parameter and the orientation of the principal axes of the electric field gradient tensor at the site of a quadrupole nucleus with half integral spin. A function is constructed from the first order splitting of the nuclear quadrupole resonance absorption line produced by a small

S. Sengupta; R. Roy; A. K. Saha

1972-01-01

112

Evidence of Antiferromagnetic Ordering in La/sub 2/CuO/sub 4/: Re-Interpretation of /sup 139/La Nuclear Quadrupole Resonance (NQR) Data.  

National Technical Information Service (NTIS)

A re-interpretation of the result of recent /sup 139/La nuclear quadrupole resonance measurements on La/sub 2/CuO/sub 4/ reveals an antiferromagnetic order in this material at low temperature. The magnitude and the direction of the local field at the La p...

I. Furo A. Janossy

1987-01-01

113

Multiple Superconducting Gaps, Anisotropic Spin Fluctuations and Spin-Orbit Coupling in Iron-Pnictides  

NASA Astrophysics Data System (ADS)

This article reviews the NMR and NQR studies on iron-based high-temperature superconductors by the IOP/Okayama group. It was found that the electron pairs in the superconducting state are in the spin-singlet state with multiple fully-opened energy gaps. The antiferromagnetic spin fluctuations in the normal state are found to be closely correlated with the superconductivity. Also, the antiferromagnetic spin fluctuations are anisotropic in the spin space, which is different from the case in copper oxide superconductors. This anisotropy originates from the spin-orbit coupling and is an important reflection of the multiple-bands nature of this new class of superconductors.

Yang, Jie; Zheng, Guo-Qing

2012-06-01

114

1,3,4-Diazaphosphorine from n-acetylurea  

SciTech Connect

In continuation of the authors study of phosphorylation of acetamides we found that N-acetylurea reacts readily with both a solution and with a dispersion of PCl/sub 5/ in benzene to form 2,6-dichloro-1,3,4-diazaphosphorine (I), a crystalline compound which is stable during distillation in vacuo, but which hydrolyzes in air. Compound (I) is soluble in benzene, diethyl ether, and chloroform. The elemental analysis and /sup 31/P, /sup 1/H, and /sup 13/C NMR and /sup 35/Cl NQR spectroscopy data conform well with the proposed structure of compound (I).

Rozinov, V.G.; Dmitrichenko, M.Yu.; Donskikh, V.I.; Dolgushin, G.V.; Feshin, V.P.

1987-07-10

115

Nuclear quadrupole resonance: a technique to control hydration processes in the pharmaceutical industry.  

PubMed

Pharmaceuticals can exist in many solid forms, which can have different physical and chemical properties. These solid forms include polymorphs, solvates, amorphous, and hydrates. Particularly, hydration process can be quite common since pharmaceutical solids can be in contact with water during manufacturing process and can also be exposed to water during storage. In the present work, it is proved that NQR technique is capable of detecting different hydrated forms not only in the pure raw material but also in the final product (tablets), being in this way a useful technique for quality control. This technique was also used to study the dehydration process from pentahydrate to trihydrate. PMID:21314133

Limandri, Silvina; Visñovezky, Claudia; Pérez, Silvina C; Schurrer, Clemar A; Wolfenson, Alberto E; Ferro, Maribel; Cuffini, Silvia L; de Souza, Joel Gonçalves; Aguiar, F Armani; de Gaitani, C Masetto

2011-02-11

116

Co Nuclear-Quadrupole-Resonance Measurements on NaxCoO2.yH2O - Phase Diagram for Bilayered-Hydrate System  

Microsoft Academic Search

Co nuclear quadrupole resonance (NQR) measurements were performed on several superconducting (SC) NaxCoO2.yH2O samples with different values of a SC transition temperature (Tc). The measurements were done for the investigation of the relationship between Tc and microscopic physical quantities derived from the Co NQR. We measured Co-NQR frequency nuQ and the nuclear-lattice relaxation rate 1\\/T1 the Co site, and found

Yoshihiko Ihara; Hideo Takeya; Kenji Ishida; Chishiro Michioka; Kazuyoshi Yoshimura; Kazunori Takada; Takayoshi Sasaki; Hiroya Sakurai; Eiji Takayama-Muromachi

2006-01-01

117

Weak Magnetic Order in Bilayered-Hydrate NaxCoO2\\\\cdotyH2O Structure Probed by Co Nuclear Quadrupole Resonance Proposed Phase Diagram in Superconducting NaxCoO2\\\\cdotyH2O---  

Microsoft Academic Search

A weak magnetic order was found in a nonsuperconducting bilayered-hydrate NaxCoO2\\\\cdotyH2O sample by Co nuclear quadrupole resonance (NQR) measurement. The nuclear spin-lattice relaxation rate divided by temperature 1\\/T_1T shows a prominent peak at 5.5 K, below which a Co NQR peak splits due to an internal field at the Co site. From the analyses of the Co NQR spectrum at

Yoshihiko Ihara; Kenji Ishida; Chishiro Michioka; Masaki Kato; Kazuyoshi Yoshimura; Kazunori Takada; Takayoshi Sasaki; Hiroya Sakurai; Eiji Takayama-Muromachi

2005-01-01

118

Alternative pyrimidine biosynthesis protein ApbE is a flavin transferase catalyzing covalent attachment of FMN to a threonine residue in bacterial flavoproteins.  

PubMed

Na(+)-translocating NADH:quinone oxidoreductase (Na(+)-NQR) contains two flavin residues as redox-active prosthetic groups attached by a phosphoester bond to threonine residues in subunits NqrB and NqrC. We demonstrate here that flavinylation of truncated Vibrio harveyi NqrC at Thr-229 in Escherichia coli cells requires the presence of a co-expressed Vibrio apbE gene. The apbE genes cluster with genes for Na(+)-NQR and other FMN-binding flavoproteins in bacterial genomes and encode proteins with previously unknown function. Experiments with isolated NqrC and ApbE proteins confirmed that ApbE is the only protein factor required for NqrC flavinylation and also indicated that the reaction is Mg(2+)-dependent and proceeds with FAD but not FMN. Inactivation of the apbE gene in Klebsiella pneumoniae, wherein the nqr operon and apbE are well separated in the chromosome, resulted in a complete loss of the quinone reductase activity of Na(+)-NQR, consistent with its dependence on covalently bound flavin. Our data thus identify ApbE as a novel modifying enzyme, flavin transferase. PMID:23558683

Bertsova, Yulia V; Fadeeva, Maria S; Kostyrko, Vitaly A; Serebryakova, Marina V; Baykov, Alexander A; Bogachev, Alexander V

2013-04-04

119

Image restoration using fast Fourier and wavelet transforms  

NASA Astrophysics Data System (ADS)

Pure nuclear quadrupole resonance (NQR) of 14N nuclei is quite promising as a method for detecting explosives such as RDX and contraband narcotics such as cocaine and heroin in quantities of interest. Pure NQR is conducted without an external applied magnetic field, so potential concerns about damage to magnetically encoded data or exposure of personnel to large magnetic fields are not relevant. Because NQR frequencies of different compounds are quite distinct, we do not encounter false alarms from the NQR signals of other benign materials. We have constructed a proof-of-concept NQR explosives detector which interrogates a volume of 300 liters (10 ft3). With minimal modification to the existing explosives detector, we can detect operationally relevant quantities of (free base) cocaine within the 300-liter inspection volume in 6 seconds. We are presently extending this approach to the detection of heroin base and also examining 14N and 35,37Cl pure NQR for detection of the hydrochloride forms of both materials. An adaptation of this NQR approach may be suitable for scanning personnel for externally carried contraband and explosives. We first outline the basics of the NQR approach, highlighting strengths and weaknesses, and then present representative results for RDX and cocaine detection. We also present a partial compendium of relevant NQR parameters measured for some materials of interest.

Harrod, William J.; Nagy, James G.; Plemmons, Robert J.

1994-02-01

120

Narcotics and explosives detection by 14N pure nuclear quadrupole resonance  

NASA Astrophysics Data System (ADS)

Pure nuclear quadrupole resonance (NQR) of 14N nuclei is quite promising as a method for detecting explosives such as RDX and contraband narcotics such as cocaine and heroin in quantities of interest. Pure NQR is conducted without an external applied magnetic field, so potential concerns about damage to magnetically encoded data or exposure of personnel to large magnetic fields are not relevant. Because NQR frequencies of different compounds are quite distinct, we do not encounter false alarms from the NQR signals of other benign materials. We have constructed a proof-of-concept NQR explosives detector which interrogates a volume of 300 liters (10 ft3). With minimal modification to the existing explosives detector, we can detect operationally relevant quantities of (free base) cocaine within the 300-liter inspection volume in 6 seconds. We are presently extending this approach to the detection of heroin base and also examining 14N and 35,37Cl pure NQR for detection of the hydrochloride forms of both materials. An adaptation of this NQR approach may be suitable for scanning personnel for externally carried contraband and explosives. We first outline the basics of the NQR approach, highlighting strengths and weaknesses, and then present representative results for RDX and cocaine detection. We also present a partial compendium of relevant NQR parameters measured for some materials of interest.

Garroway, Allen N.; Buess, M. L.; Yesinowski, J. P.; Miller, J. B.

1994-03-01

121

Case Study  

Microsoft Academic Search

The case study of Theodore Bundy compares his personal characteristics and criminal behavior with the contemporary violent sexual murder typologies. The Theodore (Ted) Bundy case study exemplifies violent sexual homicide offense characteristics. The case study will illustrate that Ted Bundy, as a single case, is the prototypical violent sexual murderer. Moreover, the Ted Bundy case study provides a unique validation

Janet McClellan

2006-01-01

122

Phase transition and temperature dependent electronic state of an organic ferroelectric, phenazine chloranilic acid (1:1)  

NASA Astrophysics Data System (ADS)

The isotope effect of hydrogen motion in an organic ferroelectric, phenazine (Phz)-chloranilic acid (H2ca and D2ca for normal and deuterated compounds, respectively) co-crystal, was studied by 35Cl nuclear quadrupole resonance (NQR). Besides a ferroelectric transition at Tc = 253 K (303 K), a neutral-to-ionic transition was found below 170 K (200 K) for Phz-H2ca (Phz-D2ca). 1H-14N nuclear quadrupole double resonance measurements were also made in order to study the temperature dependent electronic state of Phz-(H/D)2ca. 14N NQR parameters suggested that donor orbital populations of the two nitrogen atoms in a phenazine molecule become nonequivalent (1.78 and 1.97) in the ferroelectric phase, while they are both equal to 1.89 in the paraelectric phase. In the ionic phase of Phz-D2ca, which was obtained by cooling below 188 K, they became 1.50 and 1.95, suggesting a proton transfer from D2ca to Phz.

Asaji, T.; Seliger, J.; Zagar, V.; Sekiguchi, M.; Watanabe, J.; Gotoh, K.; Ishida, H.; Vrtnik, S.; Dolinšek, J.

2007-06-01

123

A vertebrate-type ferredoxin domain in the Na+-translocating NADH dehydrogenase from Vibrio cholerae.  

PubMed

The Na(+)-translocating NADH:quinone oxidoreductase from Vibrio cholerae contains a single Fe-S cluster localized in subunit NqrF. Here we study the electronic properties of the Fe-S center in a truncated version of the NqrF subunit comprising only its ferredoxin-like Fe-S domain. Mössbauer spectroscopy of the Fe-S domain in the oxidized state is consistent with a binuclear Fe-S cluster with tetrahedral sulfur coordination by the cysteine residues Cys(70), Cys(76), Cys(79), and Cys(111). Important sequence motifs surrounding these cysteines are conserved in the Fe-S domain and in vertebrate-type ferredoxins. The magnetic circular dichroism spectra of the photochemically reduced Fe-S domain exhibit a striking similarity to the magnetic circular dichroism spectra of vertebrate-type ferredoxins required for the in vivo assembly of iron-sulfur clusters. This study reveals a novel function for vertebrate-type [2Fe-2S] clusters as redox cofactors in respiratory dehydrogenases. PMID:15870079

Lin, Po-Chi; Puhar, Andrea; Türk, Karin; Piligkos, Stergios; Bill, Eckhard; Neese, Frank; Steuber, Julia

2005-05-03

124

Religious Studies.  

ERIC Educational Resources Information Center

|An essay on the study of religion at the college level and descriptions of nine programs of religious studies are presented. The essay by David C. Smith suggests that while traditional goals continue to be important, especially in church-related colleges, religious studies has expanded to include insights and materials from such disciplines as…

Mohrman, Kathryn, Ed.

1980-01-01

125

Intelligence Studies  

ERIC Educational Resources Information Center

To make an academic study of matters inherently secret and potentially explosive seems a tall task. But a growing number of scholars are drawn to understanding spycraft. The interdisciplinary field of intelligence studies is mushrooming, as scholars trained in history, international studies, and political science examine such subjects as the…

Monaghan, Peter

2009-01-01

126

Intelligence Studies  

ERIC Educational Resources Information Center

|To make an academic study of matters inherently secret and potentially explosive seems a tall task. But a growing number of scholars are drawn to understanding spycraft. The interdisciplinary field of intelligence studies is mushrooming, as scholars trained in history, international studies, and political science examine such subjects as the…

Monaghan, Peter

2009-01-01

127

Social Studies.  

ERIC Educational Resources Information Center

|The product of a Special Studies Institute, this teacher developed resource guide for the emotionally handicapped (K-6) presents social study concepts and activities relative to education in the urban out-of-doors. Focus is on the study of man (past, present, and future) interacting with his environment. Listed below are activity examples: (1)…

Bieber, Edward

128

ME-Burg Muon-spin-rotation Study of (Pr,Y)BCO: Pr in BaO layer?!  

NASA Astrophysics Data System (ADS)

Muon-spin-rotation data of polycrystalline Pr(x)Y(1-x)BCO (0 < x < 1) recorded at 1-kOe transverse fields and room temperature (RT) have been analyzed by a Maximum-Entropy (ME) Burg technique. The obtained magnetic field distributions for different Pr doping show distinct differences just below the applied field. This is inconsistent with the assumption that all Pr ions are at the rare-earth sites. NQR has suggested direct evidence of some Pr occupation of the Ba sites. [1] At RT, the muon locally probes among the Balmer sites located between the BaO and CuO-chain layers. [2] Because of charge neutrality, Ba-site occupation by Pr requires an extra negative O ion at a nearby vacancy site. These atomic changes lead to differences in the muon environment, and can explain the variations seen in the ME-Burg transforms. These magnetic field distributions have been fitted using two Lorentzians affirming consistent trends seen for the (x < 0.5) superconductors. A magnetic presence of Pr in the BaO layer may explain the disappearance of superconductivity for PrBCO. Research is supported by NHMFL, NSF-REU, DOE-LANL and WiSE@SJSU. 1] A. P. Reyes, M. M. Abdelrazek et al, M2S-HTSC-VI Conf Proc, Physica C (2000). 2] W. K. Dawson et al, Hyperfine Interactions 63 (1990) 219.

Aslanian, H. H.; Tun, M.; Abdelrazek, M. M.; Cavanaugh, S. X.; Boekema, C.

2001-03-01

129

Women's Studies.  

ERIC Educational Resources Information Center

The 16 articles in this journal issue deal with women's studies within the English curriculum. Topics discussed in the articles include (1) the feminist challenge to the male-centered curriculum in higher education; (2) the women's movement and women's studies; (3) connotations of the word "girl"; (4) women in English education; (5) the new…

Davis, James E., Ed.; Davis, Hazel K., Ed.

1981-01-01

130

Studying Zooarchaeology  

ERIC Educational Resources Information Center

|Children often associate the study of bones with dinosaurs or crime scenes. This unit introduces students to "zooarchaeology," the study of animal remains from archaeological sites. Students in grades 3-5 engage in hands-on activities examining bones, shells, and other "hard parts" of animals. They use their observations as a starting point for…

Moore, Molly; Wolf, Deborah; Butler, Virginia L.

2012-01-01

131

Women's Studies.  

ERIC Educational Resources Information Center

|The 16 articles in this journal issue deal with women's studies within the English curriculum. Topics discussed in the articles include (1) the feminist challenge to the male-centered curriculum in higher education; (2) the women's movement and women's studies; (3) connotations of the word "girl"; (4) women in English education; (5) the new…

Davis, James E., Ed.; Davis, Hazel K., Ed.

1981-01-01

132

Acoustics Studies.  

National Technical Information Service (NTIS)

The report documents the noise and vibration studies for the Bay Area rapid transit District system. Several of the studies involved the investigation of new concepts of noise and vibration control, such as the use of sound barrier walls (often called sou...

1968-01-01

133

Study Stack  

NSDL National Science Digital Library

Developed by John Weidner, the Study Stack concept basically assists individuals to memorize information about various subjects, including geography, history, math, languages, and science. Users of the site can select one of the existing stacks, which consists of virtual study cards allowing individuals to learn at their own pace until they are satisfied with their progress. What is also particularly novel about this learning tool is that data entered for customized study stacks can be automatically displayed as a matching game, a word search puzzle, or a hangman game. So far, the site contains dozens of study stacks for each subject, with the areas dedicated to math and science containing quite a number of rather helpful stacks. With its wide range of applications, this site will be very helpful to students at different age levels and teachers who may be seeking to develop a new study tool for any number of topics or themes within a subject area.

Weidner, John

134

Sleep Studies  

MedlinePLUS

... Clinical Trials Links Related Topics Sleep Apnea CPAP Narcolepsy Sleep Deprivation and Deficiency Related Media Videos Widgets ... your doctor find out whether you have a sleep disorder and how severe it is. Sleep studies are ...

135

Systems Studies.  

National Technical Information Service (NTIS)

The Systems Studies Activity had two objectives: (1) to investigate nontechnical barriers to the deployment of biomass production and supply systems and (2) to enhance and extend existing systems models of bioenergy supply and use. For the first objective...

R. L. Graham

1998-01-01

136

Conceptual Study.  

National Technical Information Service (NTIS)

This appendix is a compendium of topical reports prepared for the Hanford Nuclear Energy Center: status report: conceptual fuel cycle Studies for the Hanford Nuclear Energy Center; selection of heat disposal methods for a Hanford Nuclear Energy Center; st...

H. Harty

1978-01-01

137

Environmental Study  

ERIC Educational Resources Information Center

|Reports on a study of a pre-cooperative (the Sidi Saad pre-cooperative, Province of Tunis) as an environment in which a functional literacy program, integrated with socioeconomic development, was to be developed. (EB)|

Literacy Discussion, 1970

1970-01-01

138

Zoning Study.  

National Technical Information Service (NTIS)

The study analyzes existing zoned properties in the Shreveport Standard Metropolitan Statistical Area to determine if current development justifies the amount of such zoning. It reviews administrative procedures and policies used in carrying out zoning ch...

1968-01-01

139

Cholera studies  

PubMed Central

In this study, the author describes in detail experimental cholera infection of mammals (infection by the oral route, intragastric inoculation, and intestinal, gall-bladder, and parenteral infection). The pathogenicity for lower animals is examined, and certain observations on insects are included. The second part of the study is devoted to the pathology of human cholera (morbid anatomy distribution of the causative organisms in the dead bodies of cholera victims, and pathogenesis).

Pollitzer, R.

1955-01-01

140

Daoist Studies  

NSDL National Science Digital Library

Created and maintained by an international group of Daoism scholars, this new site hopes to offer an electronic space that promotes scholarly communication, research, teaching, and Daoist studies generally. Although thin on content at present, the site is attractive, well-organized, and with enough support from like-minded users, could become a major online resource for research and teaching in Daoist studies. The content is in two main sections: Teaching and Research. The first will feature syllabi (two are offered at time of review), recommended audiovisual materials, and guides to teaching Daoism as part of larger survey courses. The second offers a detailed research guide, event listings, paper abstracts and book notes, and related links. Other features include a collection of recommended Daoist Studies books with links to purchase information.

141

Research Study  

ERIC Educational Resources Information Center

|Background: Action Research about my 2nd grade classroom in the Buffalo School District. I examined three areas of interest and tried to find some conclusions related to behavior management. Purpose: The purpose of this study is how will implementing procedures, rules, and consequences help improve student behavior. Research Design: Descriptive;…

Glick, Ashley

2010-01-01

142

Cholera studies  

PubMed Central

The morphological characteristics, biochemical properties, and cultural characteristics of V. cholerae are described in great detail in this study. The author also discusses the resistance of the organism to temperature, humidity, sunlight, and various chemicals, as well as the viability of V. cholerae outside the body (in faeces, contaminated material, food, beverages, water, etc.).

Pollitzer, R.

1955-01-01

143

Cholera studies  

PubMed Central

Relevant information regarding the numerous problems encountered in cholera immunity is dealt with in great detail in this study. Toxin production, bacterial virulence, serological reactions, and the antigenic structure of V. cholerae are discussed. Natural, passive, and active cholera immunity receives special attention, the authors describing the various means of vaccination as well as the evaluation of the immunity induced.

Pollitzer, R.; Burrows, W.

1955-01-01

144

NEUROTOXICITY STUDIES  

EPA Science Inventory

The neurotoxicity of DBPs in general has not been well characterized. The literature provides reports of neurotoxicity of DCA following exposures to relatively high doses. Studies completed at EPA, however, have shown that relatively low doses of DCA (as low as 16 mg/kg/day; simi...

145

Sky Study.  

ERIC Educational Resources Information Center

This autoinstructional unit deals with the study of stars, constellations, and planets as part of a General Science and/or Earth Science program for students in high or middle school. Twelve behavioral objectives are identified. The equipment needed, the time suggested as adequate, and a sample of a final test that can be administered are included…

Reeder, R. P.

146

IMMUNOTOXICITY STUDIES  

EPA Science Inventory

Few D/DBPs have been evaluated for effects on the immune system, but certain studies suggest that immunosuppression may follow exposure to D/DBPs. Suppressed immune function is associated with increased susceptibility to infectious disease and certain types of cancer in humans a...

147

Cholera studies*  

PubMed Central

The first portion of this study describes in detail the different aspects of stool examinations, including the collection, preservation, and pooling of specimens, macroscopic and bacterioscopic examination, enrichment methods, and cultivation on a variety of solid media. The author also deals with the examination of vomits and of water. The performance and value of different identification tests (agglutination, haemolysis, and bacteriophage) and confirmatory tests are then considered. An annex is included on bacteriological procedures in the laboratory diagnosis of cholera.

Pollitzer, R.

1956-01-01

148

OPEN Study  

Cancer.gov

Over the course of the study, OPEN participants completed 2 Food Frequency Questionnaires (FFQ), 2 24-recall interviews, and filled out several other health-related questionnaires. They were dosed with doubly labeled water (a biomarker used for measuring energy expenditure), provided several spot urine samples to complete the doubly labeled water assessment, completed two 24-hour urine collections and had their height and weight measured.

149

Domestic Studies  

Microsoft Academic Search

My thesis consists of three essays: “Dennis,” “Would You Take a Quick Look at This,” and “Community Center.” I also have included four short stories: “The British Are Coming,” “Like Frankenstein,” “Woman’s World,” and “Auto-Man.” The final part of my thesis is a novel excerpt, “Domestic Studies.”\\u000aMy intention in my short stories is to show the alienation people feel

Wilma Diane Kelley

2007-01-01

150

The Role of Glycine Residues 140 and 141 of Subunit B in the Functional Ubiquinone Binding Site of the Na+-pumping NADH:quinone Oxidoreductase from Vibrio cholerae*  

PubMed Central

The Na+-pumping NADH:quinone oxidoreductase (Na+-NQR) is the main entrance for electrons into the respiratory chain of many marine and pathogenic bacteria. The enzyme accepts electrons from NADH and donates them to ubiquinone, and the free energy released by this redox reaction is used to create an electrochemical gradient of sodium across the cell membrane. Here we report the role of glycine 140 and glycine 141 of the NqrB subunit in the functional binding of ubiquinone. Mutations at these residues altered the affinity of the enzyme for ubiquinol. Moreover, mutations in residue NqrB-G140 almost completely abolished the electron transfer to ubiquinone. Thus, NqrB-G140 and -G141 are critical for the binding and reaction of Na+-NQR with its electron acceptor, ubiquinone.

Juarez, Oscar; Neehaul, Yashvin; Turk, Erin; Chahboun, Najat; DeMicco, Jessica M.; Hellwig, Petra; Barquera, Blanca

2012-01-01

151

Land mine detection by nuclear quadrupole resonance  

NASA Astrophysics Data System (ADS)

Nuclear Quadrupole Resonance (NQR) combines the compound specific detection capability offered by chemical detection techniques with the spatial localization capability and convenience of an induction coil metal detector. In the 16 years since NQR was last applied to mine detection in the U.S., there has been considerable improvement in the basic techniques. This paper reviews the progress achieved under a recent initiative to detect landmines by NQR. Two basic technical developments are summarized: the design of a detection coil suitable for probing the ground for landmines buried at typical depths, and an increase in the NQR signal obtained from the explosive TNT. In addition, we report the sensitivity of an NQR detection system to detect the electromagnetic response of metal-cased landmines.

Hibbs, Andrew D.; Barrall, Geoffrey A.; Czipott, Peter V.; Lathrop, Daniel K.; Lee, Y. K.; Magnuson, Erik E.; Matthews, Robert; Vierkoetter, S. A.

1998-09-01

152

Cholera studies*  

PubMed Central

In this study, figures relating to cholera deaths occurring in individual countries, from 1900 to 1952, are recorded as well as the incidence of the disease from 1923 up to the present time. The mode of spread of cholera from its endemic home in India to outside countries is described in relation to favourable seasons, main routes followed by the infection, and the role played by large religious gatherings. The incidence of the disease in the various seaports infected within recent years is discussed.

Swaroop, S.; Pollitzer, R.

1955-01-01

153

Perception studies  

NASA Astrophysics Data System (ADS)

Most United States ground-to-ground and air-to-ground military target acquisition is performed with thermal sights on today's battlefield. It is extremely important, therefore, to develop systems that provide the best compatibility to the users, to predict their performance, and to correctly train them in the use of these systems to prevent fratricide and increase survivability. It is not possible to perform all the needed research by means of expensive field tests. Therefore, the use of perception studies has become popular for developing training, testing system designs, and assessing effectiveness of sensors and systems. We discuss some challenges involved in perception studies conducted to gain insight into surveillance and target acquisition by military users of thermal imagery. The goal is to emulate as accurately as possible what a military observer will actually see and how he will use the sensor to detect and identify targets. The issues discussed include prior training, panning effects on eye movements, and contrast and brightness controls. The latest advances in these areas and some remaining challenges are discussed.

O'Kane, Barbara L.; Bonzo, David E.; Hoffman, James

2001-09-01

154

Limiter study  

SciTech Connect

Studies of energy deposition on a mushroom-shaped limiter have been performed on ZT-40M. Total energy deposition, estimated power deposition per unit area, the effects of gas puffing and vertical and error field application, and approximate time histories of the extent of the impact area are presented for two different current levels (120 and 190 kA), protrusions into the body of the plasma (+2 - +12 mm from the wall) and limiter materials. Photographs of a bare graphite and TiC-coated graphite limiter before and after exposure to the plasma are shown. Massive spallation of the TiC-coated limiter is observed at the higher current level. Spallation occurs during the discharge and after termination. The degree of spallation is dependent on the current level. The average power deposition on the limiter over the discharge is estimated to be less than or equal to 1 MW.

Downing, J.N.; Gordon, R.A.; Thomas, K.S.; Watt, R.G.

1983-08-01

155

Plague studies*  

PubMed Central

Epidemiological aspects of (a) bubonic plague and (b) primary pneumonic plague are discussed separately in this study. The cause, spread, and persistence of bubonic outbreaks are dealt with. In the case of primary pneumonic plague, the author systematically reviews the factors influencing the spread of the disease: climatic and social conditions, infectivity of the patients, immunity, and control measures. In discussing the cause of pneumonic plague outbreaks, the author deals with the possible influence of a special virulence of pneumonic strains, the role of the rodent and flea species involved, and the possibility of a pneumotropismus acquired by Pasteurella pestis. The periodicity (cyclical and secular) of bubonic plague epidemics is discussed with a view to the possible forecasting of future epidemics. The author indicates the influence of race, age, sex, and occupation on the incidence of both forms of the disease.

Pollitzer, R.

1953-01-01

156

Systems Studies  

SciTech Connect

The Systems Studies Activity had two objectives: (1) to investigate nontechnical barriers to the deployment of biomass production and supply systems and (2) to enhance and extend existing systems models of bioenergy supply and use. For the first objective, the Activity focused on existing bioenergy markets. Four projects were undertaken: a comparative analysis of bioenergy in Sweden and Austria; a one-day workshop on nontechnical barriers jointly supported by the Production Systems Activity; the development and testing of a framework for analyzing barriers and drivers to bioenergy markets; and surveys of wood pellet users in Sweden, Austria and the US. For the second objective, two projects were undertaken. First, the Activity worked with the Integrated BioEnergy Systems (TBS) Activity of TEA Bioenergy Task XIII to enhance the BioEnergy Assessment Model (BEAM). This model is documented in the final report of the IBS Activity. The Systems Studies Activity contributed to enhancing the feedstock portion of the model by developing a coherent set of willow, poplar, and switchgrass production modules relevant to both the US and the UK. The Activity also developed a pretreatment module for switchgrass. Second, the Activity sponsored a three-day workshop on modeling bioenergy systems with the objectives of providing an overview of the types of models used to evaluate bioenergy and promoting communication among bioenergy modelers. There were nine guest speakers addressing different types of models used to evaluate different aspects of bioenergy, ranging from technoeconomic models based on the ASPEN software to linear programming models to develop feedstock supply curves for the US. The papers from this workshop have been submitted to Biomass and Bioenergy and are under editorial review.

Graham, R.L.

1998-03-17

157

Peptide backbone orientation and dynamics in spider dragline silk and two-photon excitation in nuclear magnetic and quadrupole resonance  

NASA Astrophysics Data System (ADS)

In the first part of the dissertation, spider dragline silk is studied by solid state NMR techniques. The dependence of NMR frequency on molecular orientation is exploited using the DECODER experiment to determine the orientation of the protein backbone within the silk fibre. Practical experimental considerations require that the silk fibres be wound about a cylindrical axis perpendicular to the external magnetic field, complicating the reconstruction of the underlying orientation distribution and necess-itating the development of numerical techniques for this purpose. A two-component model of silk incorporating static b-sheets and polyglycine II helices adequately fits the NMR data and suggests that the b-sheets are well aligned along the silk axis (20 FWHM) while the helices are poorly aligned (68 FWHM). The effects of fibre strain, draw rate and hydration on orientation are measured. Measurements of the time-scale for peptide backbone motion indicate that when wet, a strain-dependent frac-tion of the poorly aligned component becomes mobile. This suggests a mechanism for the supercontraction of silk involving latent entropic springs that undergo a local strain-dependent phase transition, driving supercontraction. In the second part of this dissertation a novel method is developed for exciting NMR and nuclear quadrupole resonance (NQR) by rf irradiation at multiple frequencies that sum to (or differ by) the resonance frequency. This is fundamentally different than traditional NMR experiments where irradiation is applied on-resonance. With excitation outside the detection bandwidth, two-photon excitation allows for detection of free induction signals during excitation, completely eliminating receiver dead-time. A theoretical approach to describing two-photon excitation is developed based on average Hamiltonian theory. An intuition for two-photon excitation is gained by analogy to the coherent absorption of multiple photons requiring conservation of total energy and momentum. It is shown that two-photon excitation efficiency impro-ves when the two applied rf frequencies deviate from half-resonance. For two-photon NQR, it is shown that observable magnetization appears perpendicular to the excita-tion coil, requiring a second coil for detection, and that double quantum coherences are also generated. Several model systems and experimental geometries are used to demonstrate the peculiarities of two-photon excitation in NMR and NQR.

Eles, Philip Thomas

158

Fostering effective studying and study planning with study questions  

Microsoft Academic Search

In a course on biological psychology and neuropsychology, study questions were provided that also appeared as test questions in the course exam. This method was introduced to support students in active processing and reproduction of the study texts, and study planning. Data were gathered to test the hypothesis that study question use would be beneficial to course grades. In addition,

Pascal Wilhelm; Jules M. Pieters

2007-01-01

159

Details of Gender Studies  

Center for Drug Evaluation (CDER)

... Section Contents Menu. Science & Research (Drugs). ... Bioequivalence Studies. -. Details of Gender Studies. (Bioequivalence Studies). ... Study, Fast/Fed ... More results from www.fda.gov/drugs/scienceresearch

160

Spin Freezing and Recovery of Sublattice Magnetization in Lightly Doped Lanthanum Cuprate  

SciTech Connect

{sup 139}La NQR studies in lightly doped La{sub 2}Cu{sub 1-x}Li{sub x}O{sub 4} and La{sub 1.8-x}Eu{sub 0.2}Sr{sub x}CuO{sub 4} are reviewed. A strong enhancement of the {sup 139}La relaxation rate with a peak accompanied by a sudden increase of the local field at low T has been observed similarly to La{sub 2-x}Sr{sub x}CuO{sub 4}. The anomalous magnetic properties are discussed in the light of the microscopic segregation of doped holes into hole-rich domain walls separating undoped AF domains.

Suh, B.J.; Hammel, P.C.; Sarrao, J.L.; Thompson, J.D.; Fisk, Z.; Hucker, M.; Buchner, B.

1998-10-24

161

Nuclear quadrupole resonance of amidinium tetrachlorophosphorates  

SciTech Connect

The /sup 35/Cl NQR spectra and relaxation parameters of the cyclic amidinium tetrachlorophosphorates PCl/sub 4/(NCH/sub 3/)/sub 2/CX, where X = C/sub 6/H/sub 5/ (1), CCl/sub 3/ (2), and CF/sub 3/ (3), have been studied at 77/sup 0/K. The crystal of (3) has been found to contain two coexisting phases of the compound, which consist, respectively, and zwitterionic molecules of a hexacoordinated phosphorus atom with square-pyramidal symmetry of the PCl/sub 4/ group and molecules of chlorotropic isomers with a trigonal-bipyramidal environment for the phosphorus atom. The structural features of the crystalline state and the nature of the phosphorus-ligand bonds have been discussed.

Romanenko, E.A.; Kal'chenko, V.I.; Rudyi, R.B.

1986-05-01

162

Phase Transitions of (Thiourea) 3-CCl 4 Clathrate Compound  

NASA Astrophysics Data System (ADS)

An X-ray diffraction study of a clathrate compound, (thiourea)3-CCl4, was performed to elucidate the mechanism of phase transitions which are characterized by the orientational ordering of CCl4 molecules. A discontinuous change of lattice constants was observed at (39±2) K indicating the second-order phase transition and a continuous change at (64±2) K, the first-order one. Below the upper transition temperature, the space group of the lattice changed from R3c to Cc. The lower two phases belong to the same space group Cc, though the phase transition occurred. The orientation of CCl4 molecules deduced from the structural symmetry agrees with that proposed from the previous heat capacity and NQR measurements.

Yagi, Kenichiro; Shima, Shigetada; Terauchi, Hikaru; Matsuo, Takasuke

1997-09-01

163

Calculation of the nuclear quadrupole resonance spectra of YBa/sub 2/Cu/sub 3/O/sub 7/minus/x/  

SciTech Connect

Nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) studies on /sup 63,65/Cu have demonstrated the the resonance properties of these nuclei can give important information about the electronic structure of the high temperature superconductor YBa/sub 2/Cu/sub 3/O/sub 7/minus/x/ as well as the exchange coupling energy between the Cu(2) sites. Measurements for various oxygen stoichiometries have given insight into the effect of oxygen content on the valence state of the Cu. In the work reported here, the electric field gradient (EFG) tensors at the Cu(1) and Cu(2) sites in YBa/sub 2/Cu/sub 3/O/sub 7/minus/x/, have been determined from calculations on large clusters for x = 0 and 1. 13 refs., 2 tabs.

Winter, N.W.; Violet, C.E.

1989-06-01

164

Critique for What?: Cultural Studies, American Studies, Left Studies  

Microsoft Academic Search

Critique for what? Fortunately, some of the most provocative self-critical intellectuals, from the postwar period to the postmodern present, have wrestled with this question. Joel Pfister criss-crosses the Atlantic to take stock of exciting British cultural studies, American studies, and Left studies that challenge the academic critique-for-critique's-sake and career's-sake business and ask: critique for what and for whom? historicizing for

Joel Pfister

2007-01-01

165

Study Guide for TCT in Social Studies.  

ERIC Educational Resources Information Center

|This study guide is designed for individuals who are preparing to take the Georgia Teacher Certification Test (TCT) in social studies. The subareas of the test are: (1) historical development, behavioral science; (2) Georgia studies; (3) economics; (4) geography; (5) history; (6) American government; and (7) citizenship. This guide lists content…

Hutcheson, Gwen N.; Lazaroff, Edward J., Ed.

166

On the Social Study of Social Studies.  

ERIC Educational Resources Information Center

School research should be more social in nature, i.e., contextualized, interactive/dynamic, and sensitive to participant conceptions. To explore the possibilities and limitations of the social study of social studies, a conception of social research is delineated, using recent social studies classroom research as illustration. Research utilization…

Cornbleth, Catherine

1982-01-01

167

Ressonancia de quadrupolo nuclear da arsenolita. (Nuclear quadrupole resonance of arsenolite).  

National Technical Information Service (NTIS)

A pulsed Nuclear Quadrupole Resonance (NQR) spectrometer was constructed using imported Matec units. Peripherical components were specially assembled and tested for the implantation of the spin-echo technique in the Laboratorio de Centros de Cor of IFUSP....

R. Madarazo

1988-01-01

168

Off-resonance effects and selectivity profiles in pulsed nitrogen-14 nuclear quadrupole resonance.  

PubMed

In order to alleviate base-line distortions in nitrogen-14 NQR spectra originating from pulse breakthrough, low power radio-frequency (rf) pulses were applied. It is recalled that the required power is four times lower than that for an equivalent NMR experiment. This is easily explained by the fact that, in NMR, half the amplitude of the rf field is active. Moreover, the selectivity profile (i.e. the peak amplitude as a function of the difference between the carrier frequency and the resonance frequency) exhibits a shape which is, in most cases, more favorable in NQR than in NMR. An appropriate theory has been developed for explaining these experimental observations. It is concluded that low power NQR is perfectly feasible and should even be recommended for most applications, provided that the line-width of the NQR signal is not too large. PMID:23063174

Guendouz, L; Robert, A; Retournard, A; Leclerc, S; Aissani, S; Canet, D

2012-09-01

169

Brazilian Sepsis Epidemiological Study (BASES study)  

Microsoft Academic Search

INTRODUCTION: Consistent data about the incidence and outcome of sepsis in Latin American intensive care units (ICUs), including Brazil, are lacking. This study was designed to verify the actual incidence density and outcome of sepsis in Brazilian ICUs. We also assessed the association between the Consensus Conference criteria and outcome METHODS: This is a multicenter observational cohort study performed in

Eliézer Silva; Marcelo de Almeida Pedro; Ana Cristina Beltrami Sogayar; Tatiana Mohovic; Carla Silva; Mariano Janiszewski; Ruy Guilherme Rodrigues Cal; Érica de Sousa; Thereza Phitoe Abe; Joel de Andrade; Jorge Dias de Matos; Ederlon Rezende; Murillo Assunção; Álvaro Avezum; Patrícia CS Rocha; Gustavo Faissol Janot de Matos; André Moreira Bento; Alice Corrêa; Paulo Cesar Bastos Vieira; Elias Knobel

2004-01-01

170

Ethnographic Study: @ONE Technology Training Project Study.  

ERIC Educational Resources Information Center

This report presents findings from an ethnographic study of technology integration and diffusion in two California community colleges. The study was commissioned to examine whether faculty behavior and student learning outcomes have changed as a result of @ONE instructional technology training and resources. The California Community Colleges…

Obler, Susan; Schiorring, Eva

171

Generalizing from Case studies: A Case Study  

Microsoft Academic Search

Most empirical evaluations of machine learningalgorithms are case studies -- evaluationsof multiple algorithms on multiple databases.Authors of case studies implicitly or explicitlyhypothesize that the pattern of theirresults, which often suggests that one algorithmperforms significantly better thanothers, is not limited to the small numberof databases investigated, but instead holdsfor some general class of learning problems.However, these hypotheses are rarely supportedwith...

David W. Aha

1992-01-01

172

Feasibility of nuclear quadrupole resonance as a novel dosimetry tool  

Microsoft Academic Search

Nuclear quadrupole resonance (N.Q.R) frequencies are influenced by the symmetry of the charge distribution of a compound around the site of interest. Damage by ionizing radiation causes changes in this charge symmetry which can be detected by standard pulsed N.Q.R. methods. Previous work done on various chlorates of [sup 35]Cl at room temperature (Vargas et al., 1978) shows a linear

L. H. Iselin; D. E. Hintenlang; S. J. Epperson; G. A. Higgins; K. Jamil

1990-01-01

173

Feasibility of nuclear quadrupole resonance as a novel dosimetry tool  

Microsoft Academic Search

Nuclear quadrupole resonance (N.Q.R) frequencies are influenced by the symmetry of the charge distribution of a compound around the site of interest. Damage by ionizing radiation causes changes in this charge symmetry which can be detected by standard pulsed N.Q.R. methods. Previous work done on various chlorates of ³⁵Cl at room temperature (Vargas et al., 1978) shows a linear effect

L. H. Iselin; D. E. Hintenlang; S. J. Epperson; G. A. Higgins; K. Jamil

1990-01-01

174

LONGITUDINAL COHORT METHODS STUDIES  

EPA Science Inventory

Accurate exposure classification tools are required to link exposure with health effects in epidemiological studies. Exposure classification for occupational studies is relatively easy compared to predicting residential childhood exposures. Recent NHEXAS (Maryland) study articl...

175

Shanghai Women's Health Study  

Cancer.gov

The Shanghai Women's Health Study, a collaborative study by NCI, Vanderbilt University, and the Shanghai Cancer Institute, is a prospective cohort study of approximately 75,000 women, which aims to evaluate the causes of cancer among Chinese women.

176

Collaborative Ocular Melanoma Study (COMS). Study Forms.  

National Technical Information Service (NTIS)

The Collaborative Ocular Melanoma Study (COMS) is a multicenter investigation designed to evaluate therapeutic interventions for patients who have choroidal melanoma. Two randomized controlled trials are currently being conducted. Eligible patients for th...

1991-01-01

177

Advanced commercial tokamak study  

Microsoft Academic Search

Advanced commercial tokamak studies were performed by the Fusion Engineering Design Center (FEDC) as a participant in the Tokamak Power Systems Studies (TPSS) project coordinated by the Office of Fusion Energy. The FEDC studies addressed the issues of tokamak reactor cost, size, and complexity. A scoping study model was developed to determine the effect of beta on tokamak economics, and

S. L. Thomson; A. E. Dabiri; D. C. Keeton; T. G. Brown; G. T. Bussell

1985-01-01

178

Where do Children Study?  

ERIC Educational Resources Information Center

According to a study of 387 fifth-through ninth- grade students, distraction is a situationally influenced phenomenon, and students actively think about their study environments. A high percentage of students study with radio or television on, although it appears that these distractors should be removed from the ideal study environment.…

Patton, James E.; And Others

1983-01-01

179

On the Social Study of Social Studies.  

ERIC Educational Resources Information Center

This paper proposes that the study of schooling would benefit from more research that is social in nature. The characteristics of social research are described in terms of three dimensions--the extent to which "context" and "interaction" of phenomena are considered and the degree to which "participant conceptions" are incorporated in description…

Cornbleth, Catherine

180

Subchronic Toxicity Study Review  

Center for Food Safety and Applied Nutrition (CFSAN)

Text Version... TEST ANIMALS. Species/strain: Sex: Age range at initiation of study: Weight range at initiation of study: Quarantine/acclimation? ... SEX, males, females ... More results from www.fda.gov/downloads/food/guidanceregulation

181

Pediatric Study Plan Template  

Center for Drug Evaluation (CDER)

Text Version... or studies that the applicant plans to conduct ... Effectiveness and Safety Studies Planned (1-10 ... OF THE PEDIATRIC DEVELOPMENT PLAN (1-2 ... More results from www.fda.gov/downloads/drugs/developmentapprovalprocess

182

Security Studies Program.  

National Technical Information Service (NTIS)

The Security Studies Program (SSP) is a graduate level research and educational program based at the MIT Center for International Studies. It traces its origins to two initiatives. One is the teaching on international security topics, and most particularl...

2003-01-01

183

Subsidiary Requirement Study.  

National Technical Information Service (NTIS)

The study was conducted to determine 'whether foreign banks should be required to conduct banking operations in the United States through subsidiaries rather than branches.' The conclusions of the study are summarized below. A subsidiary requirement appli...

1992-01-01

184

LFOV Optimization Study.  

National Technical Information Service (NTIS)

This report describes the study of a dual reflector microwave antenna system performed by the Westinghouse Electric Corporation for the Massachusetts Institute of Technology, Lincoln Laboratory. The objectives of the study were to: (1) develop a computer ...

C. J. Miller D. Davis

1972-01-01

185

Tethered Gravity Laboratories Study.  

National Technical Information Service (NTIS)

The scope of the study is to investigate ways of controlling the microgravity environment of the International Space Station by means of a tethered system. Four main study tasks were performed. First, researchers analyzed the utilization of the tether sys...

F. Lucchetti

1990-01-01

186

Punnett Square Case Study  

NSDL National Science Digital Library

In this lesson, students will gain experience using Punnett Squares. The case study determines the probability of children having freckles from a freckled father and non-freckled mother. Illustrations guide each step of the case study.

187

Immunologic Studies in Sarcoidosis.  

National Technical Information Service (NTIS)

Studies have been concerned with investigating immunologic function in sarcoidosis, specifically mechanisms related to hypergammaglobulinemia. The studies indicate that in vitro incubation of peripheral blood mononuclear cells (PBMC) from approximately on...

J. D. Stobo

1977-01-01

188

Oregon Ports Study - 1980.  

National Technical Information Service (NTIS)

The study identifies port and land resource needs and integrates these into statewide comprehensive planning process. The major purposes of this study are to provide citizens, industry and local, state and federal government agencies a common, uniform sou...

1980-01-01

189

Esophagram (Barium Swallow Study)  

MedlinePLUS

... esophagram is a study that is completed in radiology. The test evaluates the esophagus. The esophagus is ... to wear. The study is completed in a radiology (x-ray/fluoroscopy) room. If a child is ...

190

Outer Planet Studies.  

National Technical Information Service (NTIS)

The tasks of this grant include observational studies of the composition, structure and variability of planetary and satellite atmospheres, and the investigation of the problems associated with the fundamental calibration of these data. These studies are ...

B. L. Lutz

1988-01-01

191

Hematology Practice Study Report.  

National Technical Information Service (NTIS)

The University of Southern California School of Medicine's Division of Research in Medical Education (USC/DRME) is conducting a nationwide study of practicing physicians in more than 20 medical and surgical specialties. The study's purpose is to provide a...

R. C. Mendenhall

1979-01-01

192

Annular Tank Mixing Study.  

National Technical Information Service (NTIS)

The mixing and solids suspension characteristics of a critically safe annular tank were studied. The study demonstrated the feasibility of using an annular tank for uranium solution storage. (ERA citation 06:012645)

N. P. Willis

1981-01-01

193

Afterburner Systems Study.  

National Technical Information Service (NTIS)

The results are presented of a study of afterburner or fume incinerator technology for control of gaseous combustible emissions from stationary sources. The scope of the study included evaluation of current engineering technology, evaluation of existing a...

C. R. Garbett E. R. Slater R. D. Hawthorne R. W. Rolke T. T. Phillips

1972-01-01

194

Share Food Case Study.  

National Technical Information Service (NTIS)

The Share Food Case Study was prepared for use in the 2007 Malcolm Baldrige National Quality Award Examiner Preparation Course. The Share Food Case Study describes a fictitious nonprofit organization. There is no connection between the fictitious Share Fo...

2007-01-01

195

Case Study Teaching  

ERIC Educational Resources Information Center

This chapter describes the history of case study teaching, types of cases, and experimental data supporting their effectiveness. It also describes a model for comparing the efficacy of the various case study methods. (Contains 1 figure.)

Herreid, Clyde Freeman

2011-01-01

196

Home-Study Microlabs.  

ERIC Educational Resources Information Center

Describes a pilot project for the home-study component of a first-year general chemistry course at Athabasca University that uses microscaled experiments. Presents four experiments and discusses home-study versus in-lab experience. (JRH)

Kennepohl, Dietmar

1996-01-01

197

The Study of Algae  

ERIC Educational Resources Information Center

|Included in this introduction to the study of algae are drawings of commonly encountered freshwater algae, a summary of the importance of algae, descriptions of the seven major groups of algae, and techniques for collection and study of algae. (CS)|

Rushforth, Samuel R.

1977-01-01

198

Re: Registry Study - Provenge  

Center for Biologics Evaluation and Research (CBER)

Text Version... Registry will be considered a “study and not a “trial as defined in the FDA Draft Guidance for Industry entitled, Postmarketing Studies and Clinical ... More results from www.fda.gov/downloads/biologicsbloodvaccines/cellulargenetherapyproducts

199

Case Study Teaching  

ERIC Educational Resources Information Center

|This chapter describes the history of case study teaching, types of cases, and experimental data supporting their effectiveness. It also describes a model for comparing the efficacy of the various case study methods. (Contains 1 figure.)|

Herreid, Clyde Freeman

2011-01-01

200

Case Study: Missing Link  

NSDL National Science Digital Library

This is a case study for high school and/or undergraduate students in physical anthropology. In particular this case study explores skull anatomy. Users of the National Center for Case Study Teaching in Science will be required to register (free) to gain access to the answer key (and must be of teaching status to receive the key). Included in the resource are the case overview, objectives, case study, teaching notes and answer key.

Elizabeth Strasser (Sacramento State Anthropology)

2000-09-02

201

Boeing flywheel study  

SciTech Connect

The major features of the history of the Boeing flywheel were studied. The analysis of the regenerative fuel cell was started as an outgrowth of the original Boeing study of the Space Operations Center, and was completed in November 1982 with the publication of the final report number D180-27160-1. The current flywheel effort attempts to study the integrated flywheel using the same ground rules that were used on the fuel cell study.

Rice, R.R.

1983-12-01

202

Motivation and study habits  

Microsoft Academic Search

The first part of the article reviews the literature (mainly British) on the relationships between academic performance in higher education and motivation and study habits. The distinction between goal-orientated and intrinsic motivation is used to clarify the meaning of previous studies. Among the investigations of study habits, the dimension of syllabus-boundness\\/syllabus-freedom helps to relate psychiatric work on study difficulties to

N. J. Entwistle; Jennifer Thompson; J. D. Wilson

1974-01-01

203

WISCONSIN LONGITUDINAL STUDY (WLS)  

EPA Science Inventory

The Wisconsin Longitudinal Study (WLS) is a long-term study of a random sample of 10,317 men and women who graduated from Wisconsin high schools in 1957. The WLS provides an opportunity to study of the life course, intergenerational transfers and relationships, family functioning...

204

NYU Women's Health Study  

Cancer.gov

For more than 25 years, the NYU Women’s Health Study has been committed to studying the potential causes of serious diseases in women in the United States. When the study began in 1985, its goal was to identify the role of hormones and diet in the development of the most common cancers in women, especially breast cancer.

205

Study Circles in Finland  

ERIC Educational Resources Information Center

|Finland's study circles are under the aegis of voluntary associations, and are an integral part of the national education system. They are directed by six national study centers, and in certain instances are used in combination with correspondence study programs. (MF)|

Royce, Marion

1970-01-01

206

Nebraska Social Studies Statutes.  

ERIC Educational Resources Information Center

|This booklet lists the laws that relate to Nebraska social studies. The volume is intended for administrators, teachers, and curriculum planners to assist them to do a more thorough job of planning social studies programs. The Nebraska Social Studies Statutes are designed to be a primary tool in developing a district's curriculum, as they speak…

Nebraska State Dept. of Education, Lincoln.

207

DESIGNING EFFECTIVE STUDY ENVIRONMENTS  

Microsoft Academic Search

The study setting (private or open-plan), environmental color (blue, red, or white), and study material (reading or math comprehension) were manipulated in a simulated study environment to determine their effects on adult students' mood, satisfaction, motivation, and performance. Students rated the reading task as more demanding and less enjoyable than the math task. Negative mood was slightly greater for students

NANCY J. STONE

2001-01-01

208

Case Study Research  

ERIC Educational Resources Information Center

|Case study research aims to explore and depict a setting with a view to advancing understanding. This note explores the dimensions of case study research in higher education, with special reference to geographical fieldwork. It explores Stake's three categories of case study research: intrinsic, instrumental and collective. It provides guidelines…

Cousin, Glynis

2005-01-01

209

Case Study Research  

ERIC Educational Resources Information Center

Case study research aims to explore and depict a setting with a view to advancing understanding. This note explores the dimensions of case study research in higher education, with special reference to geographical fieldwork. It explores Stake's three categories of case study research: intrinsic, instrumental and collective. It provides guidelines…

Cousin, Glynis

2005-01-01

210

STEAMBOAT CREEK FLOOD STUDY  

Microsoft Academic Search

This paper will present the development, analy- sis, calibration, and results of a comprehensive hydrologic and hydraulic study performed for the Steamboat Creek watershed, located in Reno, Nevada. The purpose of the study was to establish accurate Base Flood Elevations (BFEs) in support of a number of residential developments proposed along Steamboat Creek. There had been several studies performed over

Carla Muscarella; Todd Cochran

2007-01-01

211

ATBC Study - Current Projects  

Cancer.gov

Skip to Main Content Home Contact Us Links Study Details Questionnaires & Forms Current Projects ATBC Study Bibliography Study Investigators & Collaborators Proposal Review & Collaboration Research Consortium Projects Current Projects Prostate Lung Colorectal Pancreas Bladder Gastric Esophagus Renal Lymphomas/Leukemias Liver/biliary Head

212

LITEE Case Studies  

NSDL National Science Digital Library

The LITEE team has developed case studies designed to enhance student learning through direct participation in the decision-making process and development of higher-level cognitive skills. Case studies increase student interest in the engineering field and improve retention in engineering programs. Case Studies include lessons incorporating several different types of business models and are available to view online for free.

2010-07-28

213

Morphological Study of Lumbricals - A Cadaveric Study  

PubMed Central

The apparently simple human function of closing the hand to grasp an object or opening the palm to release it are in reality tasks of considerable mechanical complexity requiring the contraction of many individual muscles Lumbricals are important part of intrinsic musculature of hand. Though several deviations from normal have been described in standard textbooks of anatomy, a review of basic anatomy of lumbricals will be helpful. Aim: Proper knowledge about anatomy and variaitions prevalent in intrinsic musculature of hand is mandatory for various surgical procedure like cleft hand surgery, pollicization & other digital transposition procedures Present study was conducted to study morphology & variations prevalent in this region. The results were compiled and tried to find out commonest variations Phylogenetical & ontogenetical basis and clinical applications related to variations encountered were tried to know by correlating it with available literature. Material & Methods: For this study 50 hands of formalin embalmed cadavers were dissected The limbs were labelled R OR L for right or left, M or F for male or female. Cunnigham’s manual for dissection was followed for dissection. Results: Origin and nerve supply of lumbricals was normal in all hands. The variations were encountered in insertion of the 3rd lumbrical (32%) and 4th lumbrical (24%) were more confined to the right hand. Variations encountered commonly were split and misplaced insertion of third & fourth lumbricals. These variations are critically analyzed in the light of accessible literature. Conclusion: Lumbricals are more variable in the insertion rather than the origin & nerve supply. The variation commonly seen were split & misplaced insertion Split insertion was common in the third lumbrical whereas misplaced insertion is more common in the fourth lumbrical Variations are more common on right hands.

Parminder, Kaur

2013-01-01

214

The case study approach  

PubMed Central

The case study approach allows in-depth, multi-faceted explorations of complex issues in their real-life settings. The value of the case study approach is well recognised in the fields of business, law and policy, but somewhat less so in health services research. Based on our experiences of conducting several health-related case studies, we reflect on the different types of case study design, the specific research questions this approach can help answer, the data sources that tend to be used, and the particular advantages and disadvantages of employing this methodological approach. The paper concludes with key pointers to aid those designing and appraising proposals for conducting case study research, and a checklist to help readers assess the quality of case study reports.

2011-01-01

215

Scripture Study 101  

NSDL National Science Digital Library

In addition to learning HOW to study the sciptures, it\\'s important to understand WHY. OBJECTIVE The student will be able to name at least three reasons why we are to study the scriptures. The student will also be able to name three scripture study ideas. The student will demonstrate his mastery in the following three ways: (a) recording his findings in his class journal; (b) ...

Taylor, Jennie

2006-10-03

216

New marine studies center  

NASA Astrophysics Data System (ADS)

Temple University has established a Center for Marine Studies with faculty members from four of its colleges. The center will offer courses leading to a certificate in marine studies.Studies will focus on urbanization's impact on the marine environment and will focus on management and economics of waterfront utilization. In addition, faculty members will be constructing an artificial reef off Absecon Inlet to determine if increasing protective environments will permit increased sport fishing.

217

Pathology Case Study: Hydrocephalus  

NSDL National Science Digital Library

The University of Pittsburgh School of Medicine's Department of Pathology has compiled a series of case studies to help both students and instructors. In this particular study an otherwise healthy 9 month old infant is presented with hydrocephalus. The case study provides test results and images along with microscopic photos and description. Clicking on the final diagnosis provides a thorough explanation of the diagnosis and treatment.

2007-08-20

218

Research Ethics Case Studies  

NSDL National Science Digital Library

This series of case studies, developed to enhance a Trinity College Summer Research Program, raises provocative ethical questions of interest to scientists, teachers and students involved in research.

Alison J. Draper (Trinity College;); Sharon Stickley (St. Joseph College;)

2010-05-28

219

US NEUTRINO FACTORY STUDIES.  

SciTech Connect

The design and simulated performance of a second feasibility study are presented. The efficiency of producing muons is {approx} 0.17 {micro}/p with 24 GeV protons. This study was sponsored by the BNL Director, with BNL site specific driver and layout. It was a follow on to the First Study sponsored by the Fermilab Director, with Fermilab site specific driver and layout, and was the main US collaboration conceptual effort during the past year. Other studies, and technical work by the collaboration is reported in other papers.

OZAKI,S.PALMER,R.B.ZISMAN,M.S.

2001-05-24

220

STRATNET: Strategic Studies Network  

NSDL National Science Digital Library

The University of Calgary's Strategic Studies Program developed STRATNET to provide a network of research resources germane to the study of international relations, security, and politics. STRATNET includes three main sections: StratChat, an interactive discussion forum; StratLink, a well-organized collection of hundreds of annotated strategic studies pointers; and StratJournal, which contains a multidisciplinary online journal entitled STRATNET. In addition, the site provides information about the fellows and the outreach projects of the Strategic Studies Program at the University of Calgary.

221

Drop Out Remediation Study.  

ERIC Educational Resources Information Center

During spring 1991, a study was conducted at San Diego City College (SDCC) in California to explore the various factors which motivate students to drop out, propose remediation strategies based on the research findings, and suggest further studies to identify and analyze problem areas more explicitly. To examine students' reasons for dropping out,…

Geddes, John; Golbetz, Thomas

222

Army Civilian Awards Study.  

National Technical Information Service (NTIS)

A study was made of the Army civilian performance awards system to determine whether the system was adequately meeting the needs of the Army and its commanders and personnel in the field. The study revealed that the program is generally well administered,...

C. E. Thomas J. M. Alward W. E. Fanelli W. M. Fennel R. A. Haisch

1977-01-01

223

Studies In Planetary Volcanology.  

National Technical Information Service (NTIS)

Modeling and field studies of the potential for flowing lavas to erode the terrain over which they pass: this study involved numerical solutions for the heat transfer, and analysis of lava flows on Earth where erosion appears to have taken place, coupled ...

R. Greeley

2002-01-01

224

Russian demo plant study  

Microsoft Academic Search

A conceptual design study of Demo reactor is being continued in Russia. The main efforts are concentrated on the study of steady state reactor Demo-S. This reactor is to be operated in advanced plasma regime with high fraction of bootstrap current. A divertor concept with open liquid lithium as a plasma facing material was chosen. Two extreme approaches were analized:–the

Yu. A. Sokolov; I. V. Altovsky; A. A. Borisov; N. N. Vasilev; A. A. Grigorian; B. N. Kolbasov; D. K. Kurbatov; V. M. Leonov; S. A. Moshkin; V. I. Pistunovich; A. R. Polevoj; V. A. Pozharov; P. V. Romanov; Yu. S. Shpanskij; G. E. Shatalov; V. F. Zubarev; A. I. Dedurin; A. M. Suvorovand; Yu. M. Mikhailov

1998-01-01

225

Women's Studies Journals  

Microsoft Academic Search

A subset of the ongoing survey of faculty journal reading behavior at the University of New Hampshire, specifically women's studies, was used to study the journal collection that the library subscribes to and compare it to the titles that faculty say they read but to which the library does not subscribe. The data were further compared to titles listed in

Robin Lent

1998-01-01

226

Epidemiology - SEER Landmark Studies  

Cancer.gov

The area of cancer epidemiology has benefited immensely from the SEER network, a key resource not only for descriptive and correlational studies of cancer in the United States, but also for population-based case-control and cohort studies. SEER is often where changes in cancer incidence and death rates are first detected, stimulating additional epidemiologic investigation to reveal the cause.

227

Case Study Midway.  

National Technical Information Service (NTIS)

The case study of the Battle of Midway incorporates the principles of war from AFM 1-1, the definition of friction of war and illustrates those concepts using the events from the Battle of Midway. It was designed as a reading and study guide for sophomore...

P. M. St. Romain

1987-01-01

228

Age Discrimination Study.  

National Technical Information Service (NTIS)

An age discrimination study was initiated in July, 1976 in response to provisions of the Age Discrimination Act enacted by Congress in 1975. The act requires the U.S. Commission on Civil Rights to study unreasonable discrimination based on age in programs...

1977-01-01

229

Mount Storm study  

Microsoft Academic Search

A 3-year study of coniferous foliage damaged by phytotoxic elements, compounds, and particulate matter in the Mt. Storm area of West Virginia and Maryland revealed that the major causal agents are waste products from coal-burning utility plants. The primary pollutant causing damage is sulfur dioxide and its by product sulfuric acid. The SOâ in the ambient air of the study

1972-01-01

230

Before 1776. Study Guide.  

ERIC Educational Resources Information Center

|Designed for use at the elementary level, this study guide accompanies a short history of the life and culture of the Massachusetts Bay Colony prior to the American Revolution (see related document, ED 108 997). The guide provides additional material as well as a series of study questions, suggestions for additional reading, and field trips…

Gruenbaum, Thelma

231

IR Window Studies.  

National Technical Information Service (NTIS)

This document describes the results of a variety to studies of IR window materials and systems performed at the University of Southern California during 1974-75. The studies fall under three categories: a) IR window material characterization, B) IR window...

F. A. Kroger J. H. Marburger

1975-01-01

232

Introduction to Childhood Studies  

ERIC Educational Resources Information Center

|Educationalists and social scientists are increasingly interested in childhood as a distinct social category, and Childhood Studies is now a recognized area of research and analysis. This book brings together the key themes of Childhood Studies in a broad and accessible introduction for students and practitioners working in this field.…

Kehily, Mary Jane, Ed.

2004-01-01

233

Queering feminist technology studies  

Microsoft Academic Search

This article argues that the influence of heteronormativity on the conceptualization of women and technology in feminist constructivist technology studies creates serious problems for the analysis. This research aims to understand the coproduction of gender and technology in society, but does not approach the two elements in a symmetrical fashion. Hence, ethnographic studies can only exemplify how the gender of

Catharina Landström

2007-01-01

234

Facilitating Teacher Study Groups  

ERIC Educational Resources Information Center

|Although literacy coaching means many different things, all coaching initiatives have one common commitment: the goal of building teacher expertise. In the authors' work as coaches and with coaches, they have relied on teacher study groups as a main strategy for accomplishing this task. Their understanding of the potential for study groups has…

Walpole, Sharon; Beauchat, Katherine A.

2008-01-01

235

KET Social Studies Posters  

NSDL National Science Digital Library

The KET Social Studies posters provide an overview of the five “big ideas” that make up Kentucky’s K-12 social studies curriculum. These posters are appropriate for classroom display for both student and teacher reference. Each poster is available in two sizes and may be printed in color or black and white.

Ket

2012-02-15

236

Feature Extraction Assessment Study.  

National Technical Information Service (NTIS)

The purpose of the feature extraction assessment study (FEAS) is to assess the degree to which the DMA feature extraction process can be automated by 1985. The major conclusion of the study is that given the state-of-the-art in image understanding and pat...

M. J. Carlotto V. T. Tom G. K. Wallace

1984-01-01

237

Studies on Rickettsial Diseases.  

National Technical Information Service (NTIS)

New methodology for the study of rickettsiae has opened the way for an enormous range of new studies of a quantitative nature. Most important among these is the routine application of modificatons of the plaquing technique refined by wike et al., the simp...

C. L. Wisseman

1973-01-01

238

Law Studies Curriculum.  

ERIC Educational Resources Information Center

This law studies curriculum guide describes a course designed to provide secondary students with the opportunity to acquire an understanding of the U.S. legal process. The law studies course is intended to develop corresponding concepts and skills in conjunction with the content presented. The content areas of the curriculum include: (1)…

Seminole County Board of Public Instruction, Sanford, FL. Dept. of Curriculum Services.

239

Study Canada: International Outlook.  

ERIC Educational Resources Information Center

This self-contained unit of study on Canada is one of a series which can be used to supplement secondary level courses of social studies, contemporary world problems, government, history, and geography. Developed by teachers, the unit focuses on international relations. A comparative approach is used which stresses understanding Canada from…

Monahan, Robert L.; And Others

240

1978 Herbaceous Production Study.  

National Technical Information Service (NTIS)

Herbaceous productivity studies on the Geokinetics Oil Shale Project Research site in Uintah County, Utah were begun during the summer of 1978. These studies were designed to assess the amount of biomass produced by herbaceous vegetation in each of the ve...

E. R. Olgeirson

1979-01-01

241

Caspar Creek Study.  

National Technical Information Service (NTIS)

This study is designed to determine the effects of logging and road building practices on stream flow, sedimentation, and fish life and aquatic habitat in the second growth Redwood-Douglas-fir forest type. The study is located along the North and South Fo...

R. B. Thomas

1966-01-01

242

Study of strange nuclei  

SciTech Connect

A brief history of the discovery of hypernuclei is given and some recent hypernuclei studies are described. Topics include the study of p-shell hypernuclei, /sup 12/C (K/sup -/, ..pi../sup -/) experiment, and hypernuclear gamma rays. 13 references. (WHK)

Chrien, R.E.

1982-12-08

243

Teaching Social Studies Creatively.  

ERIC Educational Resources Information Center

Addresses the issue of creative teaching in social studies. Examines the way the creative classroom looks, how teachers can become more creative, and the importance of creative teaching in social studies. Concludes that creativity can foster students' understanding of social issues and aid in the retention of students until graduation. (RW)

Solomon, Warren

1989-01-01

244

Options Study - Phase II  

Microsoft Academic Search

The Options Study has been conducted for the purpose of evaluating the potential of alternative integrated nuclear fuel cycle options to favorably address the issues associated with a continuing or expanding use of nuclear power in the United States. The study produced information that can be used to inform decisions identifying potential directions for research and development on such fuel

R. Wigeland; T. Taiwo; M. Todosow; W. Halsey; J. Gehin

2010-01-01

245

Neurology Practice Study Report.  

National Technical Information Service (NTIS)

This is a report of a study on the practice of Neurology in the United States. The study, is intended to provide practice-relevant information to guide decision making in both educational program development and manpower planning. This report describes th...

R. C. Mendenhall

1979-01-01

246

Boundary layer transition studies  

Microsoft Academic Search

A small-scale wind tunnel previously used for turbulent boundary layer experiments was modified for two sets of boundary layer transition studies. The first study concerns a laminar separation\\/turbulent reattachment. The pressure gradient and unit Reynolds number are the same as the fully turbulent flow of Spalart and Watmuff. Without the trip wire, a laminar layer asymptotes to a Falkner &

Jonathan H. Watmuff

1995-01-01

247

SETDA Case Studies 2012  

ERIC Educational Resources Information Center

The State Educational Technology Directors Association (SETDA) published a series of case studies from 28 states to showcase examples of how ARRA EETT ("American Recovery and Reinvestment Act of 2009 Enhancing Education Through Technology") grant funds have impacted teaching and learning. SETDA collected data for the case studies through a variety…

State Educational Technology Directors Association, 2012

2012-01-01

248

Introduction to Childhood Studies  

ERIC Educational Resources Information Center

Educationalists and social scientists are increasingly interested in childhood as a distinct social category, and Childhood Studies is now a recognized area of research and analysis. This book brings together the key themes of Childhood Studies in a broad and accessible introduction for students and practitioners working in this field.…

Kehily, Mary Jane, Ed.

2004-01-01

249

Ontario Health Study (OHS)  

Cancer.gov

Launched in September 2010, the Ontario Health Study (OHS) is a prospective longitudinal cohort study. The OHS is an integrated platform for investigating the complex interplay of environmental, lifestyle and genetic components that increase individual and community risk of common adult diseases.

250

Contemplate Doctoral Study  

ERIC Educational Resources Information Center

|It takes an honest look for a technology teacher to determine whether he or she should engage in doctoral study. Doctoral programs have a rather high attrition rate, as high as 40 or 50%, and university resources might be better spent on those who have a greater chance of succeeding. However, for those who take the plunge, doctoral studies can be…

Flowers, Jim; Lazaros, Edward

2009-01-01

251

Biological Studies in Schizophrenia  

Microsoft Academic Search

The question of whether schizophrenia is associated with structural or functional abnormalities of the nervous system, or both, has become the principal focus of biological studies of schizophrenia. Computed tomography studies have revealed ventricular enlargement and cortical atrophy in a subgroup of schizophrenic patients. While present from the early stages of the illness, they appear to be most severe in

Herbert Y. Meltzer

1987-01-01

252

Contemporary American Indian Studies  

ERIC Educational Resources Information Center

In his keynote address to the Fifth Annual American Indian Studies Consortium in 2005 David Wilkins began by commenting on earlier attempts to formally organize such a gathering in ways that might help establish and accredit Indian studies programs. He said he had the sense that the thrust of earlier meetings "was really an opportunity for Native…

Larson, Sidner

2009-01-01

253

What Is Maternal Studies?  

Microsoft Academic Search

Maternal studies seek to critically investigate, and provide a theoretical framework to, the variety of perspectives on mothering. Pivotal to this study is the belief that mothering is a set of socially constructed activities and relationships which are positioned and contextualised within social, historical and cultural frameworks. Notions of mothering and gender are also closely intertwined and the work of

Tracey Reynolds

254

Nuclear medicine case studies  

SciTech Connect

This text presents case studies in nuclear medicine which emphasize the diagnosis of the patient's problem rather than the technical performance of the procedure. The book is arranged by organ systems and each section begins with a description of the technique and findings in a normal study.

Wagner, H.N. Jr.

1986-01-01

255

Laser ignition studies  

SciTech Connect

The goal of this work is to study the details of laser induced ignition and combustion of high-temperature condensed-phase exothermic reactions. In this work high-speed photography (HSP) and real-time optical pyrometry have been combined to provide a diagnostic tool with a 1 ms temporal resolution for studying laser ignition and combustion wave propagation. Previous experiments have involved the use of HSP for studying combustion wave propagation (1) Real-time pyrometry studies of the ignition process have also been performed previously. The present paper describes how HSP has been expanded to include three-view split-frame photography to allow the ignition and combustion processes to be recorded and studied simultaneously. 2 refs., 3 figs.

Fredin, L.; Hansen, G.P.; Margrave, J.L.; Behrens, R.G.

1985-10-01

256

BBC Prison Study  

NSDL National Science Digital Library

The official website for the BBC Prison Study, that accompanies the groundbreaking 2002 BBC Prison Study broadcast, went online in September 2008. The Prison Study put volunteers in a prison-style setting and then filmed them. The purpose of the experiment, conducted by British researchers, was to see how relationships evolved in places such as prisons, as well as in other institutions where unequal power exists, such as schools, barracks, and offices. What they found "changed our basic understanding of how groups and power work"; the study showed when and why people accept or challenge unequal power in groups. Visitors should click on "View The Movie Map", which is in the top left hand corner of the webpage, to see a menu of movie clips of different situations at the prison. The clips explore such situations as "Food Inequalities" to "Prisoners Mobilize Against Guards" to "The Emergence of a New Guard Regime". The menu in the upper left hand corner of the web page has a link to "Activities" which will prove especially useful for educators. The Activities link is further divided into the following sections, "Discussion Questions", "Exercises", and "Psychometric Tests". Each of these sections allows for more in-depth study of the issues raised by the Prison Study. The Psychometric Tests are those given to the volunteers in the study, and can be taken by visitors to the site and compared to the volunteers' scores. The "Resources" link, in the menu in the upper left hand corner of the webpage, includes hypertext links to "Scientific Publications", "Quantitative Data", and a "Glossary", that provide, respectively, a number of full-text articles about the Prison Study that have been published, the data collected during the study, and definitions of psychological terms used in the study.

2008-01-01

257

National Election Studies  

NSDL National Science Digital Library

In this season of electoral uncertainty, both researchers and concerned citizens can find the extensive data available at the National Election Studies Website quite useful. "NES conducts national surveys of the American electorate in presidential and midterm election years and carries out research and development work through pilot studies in odd-numbered years. The NES time-series now encompasses 23 biennial election studies spanning five decades." The data from these studies, along with codebooks, cover public opinion and political participation themes such as "expectations about the election outcome; perceptions and evaluations of the major parties and their candidates; interest in the campaign; information about politics; partisanship; assessments of the relative importance of major problems facing the country; attention to campaign coverage in the mass media; feelings of political efficacy; political values; conservatism vs. liberalism; trust in government; political participation; vote choice; economic well-being; positions on social welfare, economic, social, and civil rights issues" and more. Pilot studies, whose data is also available on-site, are conducted in off-election years in order "to test new, or refine existing, instrumentation and study designs." A major feature of the site, useful to not only researchers but journalists and the general public, is The NES Guide to Public Opinion and Electoral Behavior, which offers easily digestible data on a whole range of issues drawn from the time-series studies.

258

Molecular photoionization studies  

SciTech Connect

This program is concerned with the study of the electronic structure of small molecules and clusters of molecules. Of particular interest is the interaction of discrete electronic states with one another and with the various ionization and dissociation continua. Since the Second Annual Meeting of the DOE-OHER Program on The Physics and Chemistry of Energy-Related Atmospheric Pollutants in April 1981, significant progress has been made in the following areas: (1) the study of the electronic structure of dimers and small clusters of rare gas atoms using photoionization techniques; (2) similar studies on clusters of CO/sub 2/ molecules; (3) the study of electronic structure of rare gas dimers and trimers using photoelectron and photoelectron-photoion coincidence techniques; (4) the investigation of the relationship between Rydberg states in atoms, van der Waals molecules, and chemically-bonded molecules; (5) the extension of the study of photoabsorption, photoionization, and predissociation processes in H/sub 2/ to the unsymmetric isotope HD; (6) the study of photoelectron spectra of H/sub 2/ and C/sub 2/H/sub 2/; (7) a review of some of the aspects of dissociation processes in small molecules; and (8) the creation of a new program to study the spectra and dynamics of the photoionization processes in small molecules using the technique of multiphoton ionization followed by mass and electron energy analysis of the product ions and electrons. Some of the highlights of this work are reviewed.

Dehmer, P.M.

1983-01-01

259

American Studies Recommendations  

NSDL National Science Digital Library

Created and maintained by Richard P. Horwitz of the University of Iowa, this metapage offers a well-organized collection of select (unannotated) links for American Studies. The site has a nice clean design, with the links grouped by category (Material Culture, Religion, History, Jobs, etc.) and accessed via tabs at the top of the page. Horwitz has also posted the full text of a number of his articles on American Studies. The selectiveness of the site and its easy-to-use design make this an excellent starting point for anyone searching for online resources for American Studies and related topics.

Horwitz, Richard P.

260

Tokamak reactor studies  

SciTech Connect

This paper presents an overview of tokamak reactor studies with particular attention to commercial reactor concepts developed within the last three years. Emphasis is placed on DT fueled reactors for electricity production. A brief history of tokamak reactor studies is presented. The STARFIRE, NUWMAK, and HFCTR studies are highlighted. Recent developments that have increased the commercial attractiveness of tokamak reactor designs are discussed. These developments include smaller plant sizes, higher first wall loadings, improved maintenance concepts, steady-state operation, non-divertor particle control, and improved reactor safety features.

Baker, C.C.

1981-01-01

261

Decontamination solution development studies  

SciTech Connect

This study was conducted for the Westinghouse Hanford Company (WHC) by Pacific Northwest Laboratory (PNL) as part of the Hanford Grout Technology Program (HGTP). The objective of this study was to identify decontamination solutions capable of removing radioactive contaminants and grout from the Grout Treatment Facility (GTF) process equipment and to determine the impact of these solutions on equipment components and disposal options. The reference grout used in this study was prepared with simulated double-shell slurry feed (DSSF) and a dry blend consisting of 40 wt % limestone flour, 28 wt % blast furnace slag, 28 wt % fly ash, and 4 wt % type I/II Portland cement.

Allen, R.P.; Fetrow, L.K.; Kjarmo, H.E.; Pool, K.H.

1993-09-01

262

Laos case study  

PubMed Central

Peuan Mit is a Lao organization working to address the needs of children and youth living and working on the streets. This case study outlines how a trusted and strong relationship with local police provides mutual benefit.

2012-01-01

263

Airport Facilities Study.  

National Technical Information Service (NTIS)

The purpose of the investigation is to summarize the three major airport facilities in Greenville County and make reasonable projections and recommendations for future expansion of these facilities. The study includes an inventory and analysis of existing...

1970-01-01

264

Accelerator research studies  

NASA Astrophysics Data System (ADS)

The Accelerator Research Studies program at the University of Maryland, sponsored by the Department of Energy under grant number DE-FG05-91ER-40642, is currently in the first year of a three-year funding cycle. The program consists of the following three tasks: TASK 1, Study of Transport and Longitudinal Compression of Intense, High-Brightness Beams; TASK 2, Study of Collective Ion Acceleration by Intense Electron Beams and Pseudospark Produced High Brightness Electron Beams; TASK 3, Study of a Gyroklystron High-power Microwave Source for Linear Colliders. In this report we document the progress that has been made during the past year for each of the three tasks.

265

Neuropsychological Studies of Alcohol.  

National Technical Information Service (NTIS)

A series of four studies were conducted on highly practiced male volunteer subjects to investigate the relationship of electroencephalographic (EEG) parameters to alcohol-induced performance changes under conditions of low and high motivation and stress. ...

E. Callaway R. T. Jones G. C. Stone S. C. Peeke J. Doyle

1978-01-01

266

Study of Physician Socialization.  

National Technical Information Service (NTIS)

Literature on the socialization of physicians is reviewed, and a research design for the study of physicians' socialization is proposed. Three goals of the research effort are to assess past investigations into the socialization of medical students, to re...

1978-01-01

267

Nature Study Tips. Spiders.  

ERIC Educational Resources Information Center

Different types of spiders, their ranges and habits are discussed. Activities associated with the study of spiders are suggested. Four references are listed which may be of interest to beginners. (CW)

Mulaik, Stanley B.

1990-01-01

268

Gastroenterology Practice Study Report.  

National Technical Information Service (NTIS)

Descriptive and statistical analyses of the characteristics of gastroenterologists' practices in the United States are provided by this University of Southern California medical research study. Data reveal an overrepresentation of gastroenterologists in l...

1977-01-01

269

Teleportation Physics Study.  

National Technical Information Service (NTIS)

This study was tasked with the purpose of collecting information describing the teleportation of material objects, providing a description of teleportation as it occurs in physics, its theoretical and experimental status, and a projection of potential app...

E. W. Davis

2004-01-01

270

Propylene Glycol Antifreeze Study.  

National Technical Information Service (NTIS)

The use of propylene glycol (PG) base antifreeze in military vehicles is examined. Two approaches of adopting PG antifreeze into military maintenance practices are studied. The approaches include the use of a design specification and the use of a performa...

D. Davis

1996-01-01

271

Highway Subsidiaries Study.  

National Technical Information Service (NTIS)

The report studies Conrail Corporation's trucking requirements and its growth opportunities in truck transportation. The operations of two highway subsidiaries Pennsylvania Truck Lines (PTL) owned by Penn Central Transportation Company and the Reading Tra...

1975-01-01

272

Conducting Longitudinal Studies  

ERIC Educational Resources Information Center

|Although time and resource intensive, longitudinal studies offer the ability to examine the direction and magnitude of causal relationships that cannot be accomplished through cross-sectional design. (Contains 1 figure.)|

Bauer, Karen W.

2004-01-01

273

Political Studies Review  

NSDL National Science Digital Library

Sponsored by the Political Studies Association, the Political Studies Review was designed to �develop and promote the study of politics.� In particular, the editors of the Political Studies Review strive to create a space in which �new and exciting approaches to reviewing the discipline� of political science arise. The site is a great source for anyone interested in politics and is the leading source for political science book reviews in English. New reviews are regularly updated on recent materials. Not only does the site provide means to update your knowledge of recent political literature, but it is also useful to those considering publishing, as the editors consider a wide array of opinions and ideas.

Festenstein, Matthew; Smith, Martin

2006-11-11

274

Studies in Soviet Biophysics.  

National Technical Information Service (NTIS)

Contents: Electron paramagnetic resonance of iron coordination complexes with certain nucleic acid components; Study of the pi-electron structure of Watson-Crick Pairs of DNA Bases in semiempiric approximation by the self-consistent field method; The conn...

1967-01-01

275

Low Temperature Regenerator Study.  

National Technical Information Service (NTIS)

This report covers the results of a study program to determine the extent to which low temperture regenerators can be improved by utilizing size or surface effects. Subjects include surface effect contribution to specific heat; conditions necessary for si...

P. J. Walsh

1979-01-01

276

Accelerator research studies  

SciTech Connect

The Accelerator Research Studies program at the University of Maryland, sponsored by the Department of Energy under grant number DE-FG05-91ER40642, is currently in the second year of a three-year funding cycle. The program consists of the following three tasks: TASK A, Study of Transport and Longitudinal Compression of Intense, High-Brightness Beams,'' (P.I., M. Reiser); TASK B, Study of Collective Ion Acceleration by Intense Electron Beams and Pseudospark Produced High Brightness Electron Beams,'' (Co-P.I.'s, W.W. Destler, M. Reiser, M.J. Rhee, and C.D. Striffler); TASK C, Study of a Gyroklystron High-Power Microwave Source for Linear Colliders,'' (Co-P.I.'s, V.L. Granatstein, W. Lawson, M. Reiser, and C.D. Striffler). In this report we document the progress that has been made during the past year for each of the three tasks.

Not Available

1993-01-01

277

Vehicle Bumper Performance Study.  

National Technical Information Service (NTIS)

The report presents the results of a study of various aspects of vehicle bumper performance. Included are: current bumper design, override and underride propensity, ability to sustain dynamic loading, pedestrian protection, ancillary uses, and a survey of...

W. J. Rup J. M. Daly M. Erten

1968-01-01

278

Ecologic studies revisited.  

PubMed

Ecologic studies use data aggregated over groups rather than data on individuals. Such studies are popular because they use existing databases and can offer large exposure variation if the data arise from broad geographical areas. Unfortunately, the aggregation of data that define ecologic studies results in an information loss that can lead to ecologic bias. Specifically, ecologic bias arises from the inability of ecologic data to characterize within-area variability in exposures and confounders. We describe in detail particular forms of ecologic bias so that their potential impact on any particular study may be assessed. The only way to overcome such bias, while avoiding uncheckable assumptions concerning the missing information, is to supplement the ecologic with individual-level information, and we outline a number of proposals that may achieve this aim. PMID:17914933

Wakefield, Jonathan

2008-01-01

279

Cosmos: 1989 Immunology Studies.  

National Technical Information Service (NTIS)

The effects of flight during the Cosmos mission 2044 on leukocyte subset distribution and the sensitivity of bone marrow cells to colony stimulating factor-GM were determined. A parallel study with antiorthostatic suspension was also carried out. The stud...

G. Sonnenfeld

1991-01-01

280

ADVANCED CUTTINGS TRANSPORT STUDY  

SciTech Connect

This report includes a review of the progress made in ACTF Flow Loop development and research during 90 days pre-award period (May 15-July 14, 1999) and the following three months after the project approval date (July15-October 15, 1999) The report presents information on the following specific subjects; (a) Progress in Advanced Cuttings Transport Facility design and development, (b) Progress report on the research project ''Study of Flow of Synthetic Drilling Fluids Under Elevated Pressure and Temperature Conditions'', (c) Progress report on the research project ''Study of Cuttings Transport with Foam Under LPAT Conditions (Joint Project with TUDRP)'', (d) Progress report on the research project ''Study of Cuttings Transport with Aerated Muds Under LPAT Conditions (Joint Project with TUDRP)'', (e) Progress report on the research project ''Study of Foam Flow Behavior Under EPET Conditions'', (f) Progress report on the instrumentation tasks (Tasks 11 and 12) (g) Activities towards technology transfer and developing contacts with oil and service company members.

Ergun Kuru; Stefan Miska; Nicholas Takach; Kaveh Ashenayi; Gerald Kane; Len Volk; Mark Pickell; Evren Ozbayoglu; Barkim Demirdal; Paco Vieira; Affonso Lourenco

1999-10-15

281

Rock Drillability Study.  

National Technical Information Service (NTIS)

The aim of the 'Rock Drillability Study' project, started in the Laboratory of Mining Engineering in 1982, was to develope a simple and fast laboratory method of determining the drillability of rock using the smallest possible samples. Field and laborator...

P. Salminen R. Viitala

1985-01-01

282

Letter - Study-097 - Hiberix  

Center for Biologics Evaluation and Research (CBER)

... Human Services Public Health Service Food and Drug ... on the anti-PRP GMC ratio between ... Study HIB-097, could negatively impact recruitment, in ... More results from www.fda.gov/biologicsbloodvaccines/vaccines/approvedproducts

283

Civil Law Study Guide.  

National Technical Information Service (NTIS)

This study guide is intended to be a convenient reference for use by Navy and Marine Corps officers on civil law subjects. Those subjects include, inter alia, JAG Manual investigations, enlisted administrative separations, officer personnel matters, relat...

1986-01-01

284

Civil Law Study Guide.  

National Technical Information Service (NTIS)

This study guide is intended to be a convenient reference for use by Navy and Marine Corps personnel on civil law subjects. Those subjects include, inter alia, JAG Manual investigations, enlisted administrative separations, officer personnel matters, rela...

1987-01-01

285

Aircraft Cable Parameter Study.  

National Technical Information Service (NTIS)

This report describes experimental and analytical results obtained from a study of the transmission line properties of multiconductor cables commonly found on aircraft. A method for the complete characterization of multiconductor transmission lines in inh...

H. M. Fowles L. D. Scott A. K. Agrawal K. M. Lee

1977-01-01

286

Juvenile Coho Movement Study.  

National Technical Information Service (NTIS)

This pilot study was initiated to investigate movement patterns, habitat utilization, and velocity preferences for young of the year coho salmon (Oncorhynchus kisutch) during the spring in Western Washington and to examine potential factors controlling re...

S. M. Bolton J. Moss J. Southard G. Williams C. DeBlois

2002-01-01

287

Plasma Column Generation Study.  

National Technical Information Service (NTIS)

A study has been conducted on methods of producing unconfined plasma columns of length one to twenty meters in air at atmospheric pressure. Turbulent combustion gas jet and flammable liquid jets were considered for producing the plasma columns, which were...

P. S. Masser W. Cramer R. E. Petersen A. J. Hoehn E. K. Parks

1969-01-01

288

Schoolground Soil Studies.  

ERIC Educational Resources Information Center

Outlined are simple activities for studying soil, which can be conducted in the schoolyard. Concepts include soil profiles, topsoil, soil sizes, making soil, erosion, slope, and water absorption. (SJL)

Doyle, Charles

1978-01-01

289

Study of Phase Transitions.  

National Technical Information Service (NTIS)

The diamagnetic transition in CuCl has been verified, and materials studies have been carried out to determine the conditions under which this transition, which may per precursive to high temperature superconductivity, may be found. A photoactivated, defe...

I. Lefkowitz

1983-01-01

290

Studies in Soviet Biophysics.  

National Technical Information Service (NTIS)

Contents: On a mathematical model of excitation processes in Purkinje Fibre; Excitation propagation in Purkinje Fibers studied on a mathematical model; Theoretical analysis of the mechanisms of neural impulses' propagation along a non-uniform axon.

F. B. Gulko A. A. Petrov M. B. Berkinblit N. D. Vvedenskaya B. I. Khodorov

1970-01-01

291

Videofluoroscopic Swallowing Study (VFSS)  

MedlinePLUS

... or strategies help you swallow better Babies and young children can also have this test done. Your SLP can tell you more about what to expect for your child. How is the VFSS done? This study is done in ...

292

Accelerator research studies  

SciTech Connect

The Accelerator Research Studies program at the University of Maryland, sponsored by the Department of Energy under grant number DE-FG05-91ER40642, is currently in the first year of a three-year funding cycle. The program consists of the following three tasks: TASK A, Study of Transport and Longitudinal Compression of Intense, High-Brightness Beams, TASK B, Study of Collective Ion Acceleration by Intense Electron Beams and Pseudospark Produced High Brightness Electron Beams; TASK C, Study of a Gyroklystron High-power Microwave Source for Linear Colliders. In this report we document the progress that has been made during the past year for each of the three tasks.

Not Available

1992-01-01

293

Elastomer Compatibility Studies.  

National Technical Information Service (NTIS)

With the aim of a better understanding of a field problem concerning elastomer compatibility, work is carried out using a novel elastomeric (fluorocarbon) material of high temperatures, with three commercially available gas turbine lubricants. A study pro...

J. Vantilborg

1985-01-01

294

Nature Study Tips. Spiders.  

ERIC Educational Resources Information Center

|Different types of spiders, their ranges and habits are discussed. Activities associated with the study of spiders are suggested. Four references are listed which may be of interest to beginners. (CW)|

Mulaik, Stanley B.

1990-01-01

295

Unipunch capability study.  

National Technical Information Service (NTIS)

A universal mechanical operating system (designated the ''Unipunch''), which is a flexibly adjustable punching system used at Mound to punch clearance and tooling holes in flexible circuit materials, was studied to determine its capabilities. A designed e...

M. E. Sterrett R. S. Ramachandran

1991-01-01

296

EPR Studies in Autoxidation.  

National Technical Information Service (NTIS)

Two electron paramagnetic resonance (EPR) techniques flow analysis and spin-trapping, are described that are particularly useful for studying radical reactions too fast for detection by conventional EPR. They will be powerful tools for distinguishing init...

K. M. Schaich D. C. Borg

1979-01-01

297

Advanced Chemical Propulsion Study.  

National Technical Information Service (NTIS)

A study was performed of advanced chemical propulsion technology application to space science (Code S) missions. The purpose was to begin the process of selecting chemical propulsion technology advancement activities that would provide greatest benefits t...

G. Woodcock D. Byers L. A. Alexander A. Krebsbach

2004-01-01

298

Rama reservoir model study  

SciTech Connect

Although the Rama field is known to have a large volume of oil-in-place, performance data indicate a relatively low primary recovery. Pertamina and Iiapco jointly performed a reservoir model study to determine the potential for improving performance by supplementing primary recovery techniques now in effect. This work provides a case study in the use of computer models to simulate a producing reservoir. The study describes the development of the model and the manner in which it was used to gain a better understanding of the reservoir mechanics unique to the Rama field. The study resulted in a more accurate assessment of primary recovery potential, and it defined the improvement in performance that can be expected through a program of infill drilling and secondary recovery techniques.

Kovacs, P.P.

1982-01-01

299

Total Diet Study - References  

Center for Food Safety and Applied Nutrition (CFSAN)

... US Food and Drug Administration's Total Diet Study: Intake of Nutritional and Toxic Elements, 1991-96. Food Addit. Contam. 19(2):103-125. ... More results from www.fda.gov/food/foodscienceresearch/totaldietstudy

300

Educational Case Studies  

Center for Drug Evaluation (CDER)

... Web pages for Derma-Smoothe Body Oil. Download the following materials to perform the Derma-Smoothe Case Study: ... More results from www.fda.gov/drugs/guidancecomplianceregulatoryinformation/surveillance

301

Trace Element Equilibrium Studies.  

National Technical Information Service (NTIS)

The equilibrium distribution coefficients of trace elements in seawater on ion-exchange resins were investigated. These resins contained various organic complexing and precipitating agents known to react with the elements under study. The resins used were...

J. D. Gassaway

1973-01-01

302

Brazil Transport Study Models.  

National Technical Information Service (NTIS)

This paper describes two applications of systems models to transportation planning problems in Brazil. The basic objective of the two studies is essentially the same-- transport project identification and preliminary evaluation for an entire mode or secto...

C. G. Harral

1970-01-01

303

Agricultural Health Study  

Cancer.gov

A fact sheet about the Agricultural Heath Study, begun In 1993 by scientists from the National Cancer Institute, the National Institute of Environmental Health Sciences, and the U.S. Environmental Protection Agency.

304

Timings for Efficacy Studies  

Center for Biologics Evaluation and Research (CBER)

... HPV-009, A double blind, controlled, randomized, phase III study of the efficacy of an HPV16/18 VLP vaccine in the prevention of advanced cervical ... More results from www.fda.gov/biologicsbloodvaccines/vaccines/approvedproducts

305

Family History Validation Study  

Cancer.gov

The Family History Validation Study is a methodologic study to assess the completeness and accuracy of self-reports of family history of cancer. A questionnaire was administered by computer-assisted telephone interviewing (CATI) to a probability sample of 1,380 Connecticut residents, ages 25-64 years. The questionnaire asked about the occurrence of cancer in first- and second-degree relatives, except for grandchildren.

306

DWPF welder parametric study  

Microsoft Academic Search

As part of the DWPF Startup Test Program, a parametric study has been performed to determine a range of welder operating parameters which will produce acceptable final welds for canistered waste forms. The parametric window of acceptable welds defined by this study is 90,000 ± 15,000 lb of force, 248,000 ± 22,000 amps of current, and 95 ± 15 cycles

B. J. Eberhard; J. R. Harbour; M. J. Plodinec

1994-01-01

307

The zurich study  

Microsoft Academic Search

From data collected within the frame of a longitudinal epidemiologic study of a representative sample population of young adults (the Zurich Study), anxiety disorders—anxiety and phobic states—were analyzed. The current prevalence rate was found to be 2.9% for anxiety states and 4.3% for phobic states, totaling 7.2%. Because of their anxiety disorders, one-fifth of the cases had undergone treatment during

J. Angst; A. Dobler-Mikola

1985-01-01

308

Pharmacokinetic study of stobadine.  

PubMed

The aim of this paper is to provide a brief overview of most important results of stobadine kinetic studies in rats, dogs, and human volunteers. In these studies, stobadine dihydrochloride and stobadine dipalmitate was used for intravenous and oral administration, respectively. To evaluate kinetic properties of stobadine and its metabolites, TLC, HPLC, GLC, GC-MS, radiometric, and fluorometric methods were developed and used. PMID:10576455

Bezek, S; Soltés, L; Scasnár, V; Bauerová, K; Kállay, Z; Durisová, M; Mihalová, D; Bohov, P; Faberová, V; Kukan, M; Trnovec, T; Koprda, V

1999-01-01

309

Genome Wide Association Studies  

NASA Astrophysics Data System (ADS)

The availability of high throughput technology for parallel genotyping has opened the field of genetics to genome-wide association studies (GWAS). These studies generate massive amount of genetic data that challenge investigators with issues related to data management, statistical analysis of large data sets, visualization, and annotation of results. We will review the common approach to analysis of GWAS data and then discuss options to learn more from these data.

Sebastiani, Paola; Solovieff, Nadia

310

Longitudinal-Experimental Studies  

Microsoft Academic Search

\\u000a Longitudinal-experimental studies are follow-up surveys that include an experimental intervention. The main advantage of these\\u000a surveys is that it is possible to study both the natural history of development and the impact of interventions in one research\\u000a project. This chapter focusses on large-scale community surveys with repeated personal interviews with participants spanning\\u000a at least 5 years. It reviews the advantages

David P. Farrington; Rolf Loeber; Brandon C. Welsh

311

Twin Studies of Behavior  

Microsoft Academic Search

In the age of molecular genetics some commentators have questioned whether twin studies will continue to be a useful tool\\u000a for studying genetic influences on behavior. Many of us think the answer is yes (Bouchard & Propping, 1993). Work with monozygotic\\u000a twins reared apart provides an imperfect, but nevertheless powerful window on the direct influence of genes on whole organisms.

Thomas J. Bouchard

312

Women's Studies Pages  

NSDL National Science Digital Library

The University of Maryland Baltimore County maintains two very useful pages of women's studies pointers. One offers an alphabetical list of over 100 selected women's and gender related sites of all types. To make the list easier to navigate, it has also been divided by topic, including activism, arts and humanities, health, international, net info, science/technology, and sexuality, as well as a separate list pointing to over 40 national and international university women's studies programs and research centers. The second page provides an annotated collection of over 200 women's issues and gender studies email lists. Again, the collection is presented both alphabetically and by topic, including the topics above plus religion/spirituality lists, social science lists, women of color lists, and womens studies lists. Both pages are excellent sources of women's studies information on the Internet, and the email list page is one of the more comprehensive pages available. Women's Studies WWW Pages and gophers: http://www-unix.umbc.edu/~korenman/wmst/links.html Gender Related Electronic Forums: http://www-unix.umbc.edu/~korenman/wmst/forums.html

313

Model evaluation studies  

SciTech Connect

The Office of Health and Environmental Research (OHER) of the US Department of Energy (DOE) sponsors an ongoing series of atmospheric field studies whose main objectives are to increase fundamental knowledge of atmospheric transport and dispersion. This knowledge is used to develop technologies and methodologies required for both air quality assessments and real-time emergency response. These field studies have ranged from point releases of tracers in relatively simple terrain, to intensive field studies in extremely complex terrain. Scales have ranged from the mesoscale to the synoptic. This paper will give an overview of several DOE/OHER sponsored field experiments with particular emphasis on the role they have played in helping to improve and evaluate real-time atmospheric transport and dispersion models. The Mesoscale Atmospheric Transport Studies (MATS) and STable Atmospheric Boundary Layer Experiment (STABLE), conducted at Savannah River Site in South Carolina, have provided valuable data for model evaluation over gently rolling forested terrain. In contrast, the extensive series of Atmospheric Studies in COmplex Terrain (ASCOT) involve experiments in the extremely complex terrain of the Geysers area of northern California and Brush Creek in Colorado. Remote sensing has played a significant role in ASCOT in providing meteorological parameters for input into models. The vital role played by models in the initial design of these experiments will also be discussed. 41 refs., 3 figs., 1 tab.

Addis, R.P.; Bunker, S.S.; Dobosy, R.J.; Lange, R.; Porch, W.M. (Westinghouse Savannah River Co., Aiken, SC (USA); Los Alamos National Lab., NM (USA); National Oceanic and Atmospheric Administration, Oak Ridge, TN (USA). Air Resources Lab. Atmospheric Turbulence and Diffusion Div.; Lawrence Livermore National Lab., CA (USA); Los Alamos National Lab., NM (USA))

1989-01-01

314

[The DIAN Study].  

PubMed

Abstract The DIAN study compared the pathophysiological markers between carriers and non-carriers of mutation for autosomal dominant Alzheimer's disease (AD). They used the participant's age at baseline assessment and the parent's age at the onset of symptoms of AD to calculate the estimated delay in symptom onset. The study revealed that the biomarker change, which is the reduction of A?42 in the CSF of the carrier's brain, started approximately 15-20 years prior to the onset of symptoms. Subsequently, a chronological series of events took place: deposition of fibrillar A? as measured by positron emission tomography with the use of Pittsburgh compound B, increase in tau protein in the CSF, hippocampal atrophy and hypometabolism of FDG-PET, and cognitive and clinical changes. The researchers planned to start the prevention trial with 2 monoclonal antibodies and a BACE inhibitor. In contrast, the API study is the clinical trial of the anti-amyloid monoclonal antibody therapy associated with the early-onset familial AD (EOAD), which carries the PSEN1 E280A mutation. This study also showed changes in the same biomarker as reported in the DIAN study. Anti-amyloid treatment in asymptomatic AD (A4) is a prevention trial aimed at treating older individuals with normal cognition but at risk of developing AD dementia on the basis of having biomarker evidence of amyloid (preclinical AD). They selected solanezumab for the anti-amyloid treatment for A4. PMID:24101429

Shimada, Hiroyuki

2013-10-01

315

ADVANCED CUTTINGS TRANSPORT STUDY  

SciTech Connect

This is the second quarterly progress report for Year 2 of the ACTS project. It includes a review of progress made in Flow Loop development and research during the period of time between Oct 1, 2000 and December 31, 2000. This report presents a review of progress on the following specific tasks: (a) Design and development of an Advanced Cuttings Transport Facility (Task 2: Addition of a foam generation and breaker system), (b) Research project (Task 6): ''Study of Cuttings Transport with Foam Under LPAT Conditions (Joint Project with TUDRP)'', (c) Research project (Task 7): ''Study of Cuttings Transport with Aerated Muds Under LPAT Conditions (Joint Project with TUDRP)'', (d) Research project (Task 8): ''Study of Flow of Synthetic Drilling Fluids Under Elevated Pressure and Temperature Conditions'', (e) Research project (Task 9): ''Study of Foam Flow Behavior Under EPET Conditions'', (f) Research project (Task 10): ''Study of Cuttings Transport with Aerated Mud Under Elevated Pressure and Temperature Conditions'', (g) Research on instrumentation tasks to measure: Cuttings concentration and distribution in a flowing slurry (Task 11), and Foam properties while transporting cuttings. (Task 12), (h) Development of a Safety program for the ACTS Flow Loop. Progress on a comprehensive safety review of all flow-loop components and operational procedures. (Task 1S). (i) Activities towards technology transfer and developing contacts with Petroleum and service company members, and increasing the number of JIP members. The tasks Completed During This Quarter are Task 7 and Task 8.

Troy Reed; Stefan Miska; Nicholas Takach; Kaveh Ashenayi; Gerald Kane; Mark Pickell; Len Volk; Mike Volk; Barkim Demirdal; Affonso Lourenco; Evren Ozbayoglu; Paco Vieira; Lei Zhou

2000-01-30

316

Laboratory microfusion capability study  

SciTech Connect

The purpose of this study is to elucidate the issues involved in developing a Laboratory Microfusion Capability (LMC) which is the major objective of the Inertial Confinement Fusion (ICF) program within the purview of the Department of Energy's Defense Programs. The study was initiated to support a number of DOE management needs: to provide insight for the evolution of the ICF program; to afford guidance to the ICF laboratories in planning their research and development programs; to inform Congress and others of the details and implications of the LMC; to identify criteria for selection of a concept for the Laboratory Microfusion Facility and to develop a coordinated plan for the realization of an LMC. As originally proposed, the LMC study was divided into two phases. The first phase identifies the purpose and potential utility of the LMC, the regime of its performance parameters, driver independent design issues and requirements, its development goals and requirements, and associated technical, management, staffing, environmental, and other developmental and operational issues. The second phase addresses driver-dependent issues such as specific design, range of performance capabilities, and cost. The study includes four driver options; the neodymium-glass solid state laser, the krypton fluoride excimer gas laser, the light-ion accelerator, and the heavy-ion induction linear accelerator. The results of the Phase II study are described in the present report.

Not Available

1993-05-01

317

ADVANCED CUTTINGS TRANSPORT STUDY  

SciTech Connect

This is the first quarterly progress report for Year 2 of the ACTS project. It includes a review of progress made in Flow Loop development and research during the period of time between July 14, 2000 and September 30, 2000. This report presents information on the following specific tasks: (a) Progress in Advanced Cuttings Transport Facility design and development (Task 2), (b) Progress on research project (Task 8): ''Study of Flow of Synthetic Drilling Fluids Under Elevated Pressure and Temperature Conditions'', (c) Progress on research project (Task 6): ''Study of Cuttings Transport with Foam Under LPAT Conditions (Joint Project with TUDRP)'', (d) Progress on research project (Task 7): ''Study of Cuttings Transport with Aerated Muds Under LPAT Conditions (Joint Project with TUDRP)'', (e) Progress on research project (Task 9): ''Study of Foam Flow Behavior Under EPET Conditions'', (f) Initiate research on project (Task 10): ''Study of Cuttings Transport with Aerated Mud Under Elevated Pressure and Temperature Conditions'', (g) Progress on instrumentation tasks to measure: Cuttings concentration and distribution (Tasks 11), and Foam properties (Task 12), (h) Initiate a comprehensive safety review of all flow-loop components and operational procedures. Since the previous Task 1 has been completed, we will now designate this new task as: (Task 1S). (i) Activities towards technology transfer and developing contacts with Petroleum and service company members, and increasing the number of JIP members.

Troy Reed; Stefan Miska; Nicholas Takach; Kaveh Ashenayi; Gerald Kane; Mark Pickell; Len Volk; Mike Volk; Barkim Demirdal; Affonso Lourenco; Evren Ozbayoglu; Paco Vieira

2000-10-30

318

Rugby headgear study.  

PubMed

A two year randomised controlled trial of headgear in Rugby Union football is being conducted in Sydney, Australia. This paper gives an overview of this study in progress and presents results related to the development and laboratory performance of the headgear. The study commenced in 2002. Participants recruited to the study are in the under 13, 15, school open (U18) and colts age groups. There are three study arms: control, IRB-approved headgear, and modified headgear. The IRB approved headgear is a popular model in rugby, the Canterbury Honeycomb model manufactured by BodyArmour in New Zealand. The dimensions of this model were altered by increasing foam density and thickness to produce the modified headgear. In impact energy attenuation tests of 15 and 20 Joules onto a flat anvil, the modified headgear demonstrated average maximum headform accelerations of 23% and 33% of the standard model, respectively. Whether or not this improvement translates into reductions in injury will be determined by a comparison of the rates and severities of head injuries across study arms. Furthermore, these dimensional changes may not be acceptable to rugby players. Player attitudes towards safety and the use of protective clothing, injury history, experience and on-field behaviour will be examined via structured pre- and end of season surveys and analysis of match video. PMID:14609153

McIntosh, A S; McCrory, P; Finch, C F; Chalmers, D J; Best, J P

2003-09-01

319

Ventilation technologies scoping study  

SciTech Connect

This document presents the findings of a scoping study commissioned by the Public Interest Energy Research (PIER) program of the California Energy Commission to determine what research is necessary to develop new residential ventilation requirements for California. This study is one of three companion efforts needed to complete the job of determining the needs of California, determining residential ventilation requirements, and determining appropriate ventilation technologies to meet these needs and requirements in an energy efficient manner. Rather than providing research results, this scoping study identifies important research questions along with the level of effort necessary to address these questions and the costs, risks, and benefits of pursuing alternative research questions. In approaching these questions and level of effort, feasibility and timing were important considerations. The Commission has specified Summer 2005 as the latest date for completing this research in time to update the 2008 version of California's Energy Code (Title 24).

Walker, Iain S.; Sherman, Max H.

2003-09-30

320

Wright Field turboprop study  

SciTech Connect

The considered investigation was conducted as part of an effort to reduce aircraft fuel costs. Turboprops are very fuel efficient at speeds below Mach 0.6. One of the most promising approaches to reduce fuel consumption in the speed range from Mach 0.6 to 0.8 is related to an employment of the swept eight to ten blade propeller (propfan) being developed by NASA. All studies to date indicate that turboshaft engines with propfans might save 15% or more of the fuel used by a turbofan engine of comparable technology. Attention is given to a turboprop status review, contractor studies, the NASA propfan program, an in-house performance study, specific problems which have to be solved to make a twin-turboprop, 100-150 passenger transport a viable possibility for the early 1990s, and turboprop dilemmas.

Lorenzetti, R.C.; Dull, P.P.

1981-01-01

321

Salt studies: Conclusions  

NASA Astrophysics Data System (ADS)

This report represents the conclusion of the compressed air energy storage (CAES) program in salt. It includes a brief background of salt cavity studies and utilization for CAES, the focuses on long-term stability criteria for solution mined salt cavities. Summary statements are made on some of the more important criteria and their significance for operational peaking-power plants utilizing salt cavities for CAES reservoirs. The concluding section of this report incorporates a discussion of the future for CAES in U.S. salt deposits. This discussion is based mainly on technical considerations, since they have been the main consideration in this particular study. Obviously, economic analyses will dominate decisions by utilities on construction schedules for any technically feasible CAES study.

Thoms, R. L.; Gehle, R. M.

1982-12-01

322

Study of electroweak interactions  

SciTech Connect

The experimental study of electroweak interactions at Virginia Tech is multifaceted and consists of three parts. The first consists of analysis of the final states of matter produced in electron-positron annihilations at center-of-mass energies {radical}s = 60 GeV at the TRISTAN collider in Japan (AMY). The second is a sensitive search for rare electroweak processes through a study of {mu}{sup +} {yields} e{sup +}{sub {gamma}} at the LAMPF facility at Los Alamos (MEGA). It also includes a precise measurement of the Michel {rho} parameter (RHO). The third activity is a R & D detector development and is a precursor to anticipated experiments at proposed B{sup o} meson factories in this country and/or abroad. The physics goals are the study of CP violation in the B{sup o} system and the determination of the values for Kobayashi-Maskawa matrix.

Abashian, A.; Gotow, K.; Piilonen, L.; Morgan, N.

1992-10-01

323

Center for seismic studies  

NASA Astrophysics Data System (ADS)

A 1992 study by Suteau-Henson where azimuth bias and scatter were systematically measured for regional phases of events recorded at ARCESS is extended here by mapping the observed bias and scatter around ARCESS. In another study, the optimization of polarization analysis at IMS/IRIS stations in the Former Soviet Union is addressed. Also in this report, a procedure to stack waveforms recorded by a network of seismic stations for detection of depth phases, sP and pP is defined. The constraint on focal depth provided by origin times determined from travel time ratios of P and S waves is also studied. Finally, we perform some computational experiments to outline the depth estimation capability of the GSETT-2 global network and a hypothetical network consisting primarily of high sensitive array stations.

Henson, Anne; Israelsson, Hans

1994-02-01

324

Iron studies in hemophilia  

SciTech Connect

Although iron deficiency is not recognized as a usual complication of hemophilia, we questioned whether intermittent occult loss of blood in urine or stool might predispose hemophiliacs to chronic iron deficiency. Seven men with factor VII and one with factor IX deficiency were studied. Blood studied, bone marrow aspirates, urine and stool samples, and ferrokinetics with total-body counting up to five months were examined. These data showed no excessive loss of blood during the study period; however, marrow iron stores were decidedly decreased, being absent in four subjects. We suggest that in some hemophiliacs, iron deposits in tissues such as synovial membranes may form a high proportion of the body's total iron stores.

Lottenberg, R.; Kitchens, C.S.; Roessler, G.S.; Noyes, W.D.

1981-12-01

325

Hardrock studies: Conclusions  

NASA Astrophysics Data System (ADS)

The objective of the hard rock reservoir stability studies project was to develop geotechnical criteria for the design and stability of caverns in hard rock formations that would be used to store compressed air for utility load leveling operations. To develop these criteria, a sequence of studies was formulated including state-of-the-art assessment, numerical model development, and an experimental program. This sequence was started in FY 1978 and completed FY 1981. During FY 1982, final stability criteria and guidelines were assembled into a report that integrated the geotechnical data base obtained from the sequence of hard rock studies. This document provides a resource that can be used to address concerns regarding long-term cavern stability by those who are responsible for CAES development.

Fossum, A. F.

1982-12-01

326

Proton dynamics in the strong chelate hydrogen bond of crystalline picolinic acid N-oxide. A new computational approach and infrared, raman and INS study.  

PubMed

Infrared, Raman and INS spectra of picolinic acid N-oxide (PANO) were recorded and examined for the location of the hydronic modes, particularly O-H stretching and COH bending. PANO is representative of strong chelate hydrogen bonds (H-bonds) with its short O...O distance (2.425 A). H-bonding is possibly well-characterized by diffraction, NMR and NQR data and calculated potential energy functions. The analysis of the spectra is assisted by DFT frequency calculations both in the gas phase and in the solid state. The Car-Parrinello quantum mechanical solid-state method is also used for the proton dynamics simulation; it shows the hydron to be located about 99% of time in the energy minimum near the carboxylic oxygen; jumps to the N-O acceptor are rare. The infrared spectrum excels by an extended absorption (Zundel's continuum) interrupted by numerous Evans transmissions. The model proton potential functions on which the theories of continuum formation are based do not correspond to the experimental and computed characteristics of the hydrogen bond in PANO, therefore a novel approach has been developed; it is based on crystal dynamics driven hydronium potential fluctuation. The envelope of one hundred 0 --> 1 OH stretching transitions generated by molecular dynamics simulation exhibits a maximum at 1400 cm-1 and a minor hump at approximately 1600 cm-1. These positions square well with ones predicted for the COH bending and OH stretching frequencies derived from various one- and two-dimensional model potentials. The coincidences with experimental features have to be considered with caution because the CPMD transition envelope is based solely on the OH stretching coordinate while the observed infrared bands correspond to heavily mixed modes as was previously shown by the normal coordinate analysis of the IR spectrum of argon matrix isolated PANO, the present CPMD frequency calculation and the empirical analysis of spectra. The experimental infrared spectra show some unusual characteristics such as large temperature effects on the intensity of some bands, thus presenting a challenge for theoretical band shape treatments. Our calculations clearly show that the present system is characterized by an asymmetric single well potential with no large amplitudes in the hydronium motion, which extends the existence of Zundel-type spectra beyond the established set of hydrogen bonds with large hydronic vibrational amplitudes. PMID:18225869

Stare, Jernej; Panek, Jaros?aw; Eckert, Juergen; Grdadolnik, Joze; Mavri, Janez; Hadzi, Dusan

2008-01-29

327

Hydrogen bonds in cocrystals and salts of 2-amino-4,6-dimethylpyrimidine and carboxylic acids studied by nuclear quadrupole resonance.  

PubMed

(14)N and (17)O nuclear quadrupole resonance frequencies have been measured in 1:1 cocrystals and salts of 2-amino-4,6-dimethylpyrimidine and several carboxylic acids. A systematic decrease of the (17)O quadrupole coupling constant on increasing strength of the hydrogen bond is observed in cocrystals bound by O-H···N hydrogen bonds. The O-H distances deduced from the line widths of the (17)O NQR lines show that the hydrogen atom is in a hydrogen bond formed by a carboxylic groups for about 0.01 nm displaced from the oxygen atom toward the center of the hydrogen bond. In the O-H···N hydrogen bond formed by the hydroxyl group, which is only slightly longer than the hydrogen bonds formed by the carboxyl group, the hydrogen atom is much less displaced. A linear relation between the (14)N quadrupole coupling constant and the sum of the inverse third powers of the H···A (A = O or N) distances is deduced for the amino group. A linear correlation of the principal values of the (14)N quadrupole coupling tensor in -NH2, as observed in the solid phase and in the gas phase, is analyzed in a simple model assuming a displacement of the electron charge in the N-H ? bond and simultaneous deformation of the nitrogen lone pair electron orbital. At the ring nitrogen position, hydrogen bonding and proton transfer produce a large decrease of the (14)N quadrupole coupling constant. A linear correlation of the principal values of the (14)N quadrupole coupling tensor is observed in cocrystals and salts of 2-amino-4,6-dimethylpyrimidine. This correlation differs from the correlation observed in substituted pyrimidine, where the hydrogen atoms are replaced by other atoms or functional groups. The difference is analyzed in a model, which assumes that the hydrogen bonding and substituents affect the nitrogen lone pair and ? electron orbitals. The analysis shows that the two effects are nearly independent. PMID:23675946

Seliger, Janez; Žagar, Veselko

2013-05-29

328

DWPF Welder Parametric Study  

SciTech Connect

After being filled with glass, DWPF canistered waste forms will be welded closed using an upset resistance welding process. This final closure weld must be leaktight, and must remain so during extended storage at SRS. As part of the DWPF Startup Test Program, a parametric study (DWPF-WP-24) has been performed to determine a range of welder operating parameters which will produce acceptable welds. The parametric window of acceptable welds defined by this study is 90,000 + 15,000 lb of force, 248,000 + 22,000 amps of current, and 95 + 15 cycles* for the time of application of the current.

Plodinec, M.J.

1998-11-20

329

Laser nuclear studies  

NASA Astrophysics Data System (ADS)

The ability of optical pumping to produce nuclear orientation and the advent of single frequency tunable dye lasers has brought about a new interesting area of study, Laser Induced Nuclear Orientation (LINO). The impact of LINO on the nuclear structure studies of short lived nuclei along with a discussion on various relaxation mechanisms involved are presented. As an example, recent experimental results on85mRb (T1/2=1.0 ?s) are given in detail. Possible application of LINO to151Eu discussed.

Dasari, Ramachandra R.; Shimkaveg, Gregory M.; Otteson, Michael S.; Feld, Michael S.

1987-12-01

330

Social Studies School Service  

NSDL National Science Digital Library

Beginning this month, socialstudies.com offers an Online Course for New History/ Social Studies Teachers designed to provide new teachers with icebreakers, lesson plans, background pedagogy, and activities for the classroom. Currently, IceBreakers, Introduction to Social Studies, and Lesson Planning (including over a dozen sample lessons) are online with Creative Lessons, Idea Books and Activities, and Assessment to follow. Lesson Planning also gives lists of supplementary print resources from socialstudies.com, which may be purchased online, and links to useful educational Websites.

331

Mycology studies in space.  

PubMed

The postflight phase of the Apollo MEED mycology attempts to identify survival according to exposure to specific quantitative space flight factors, while the second phase of studies identifies qualitative change other than cell survival [57]. Initial changes incurred in space on a fungal cell can be monitored and further examined on return of the fungal species test system to Earth. The postflight studies present a better understanding of the space environmental influences on living cells and a more clear understanding of the fungal species under examination. PMID:2325748

Volz, P A

1990-02-01

332

Combinitorial resist processing studies  

NASA Astrophysics Data System (ADS)

A new processing tool, the Thermal Gradient Plate (TGP) is described. The TGP allows for a range of temperatures to be expressed on a wafer or other substrate in a controlled and reproducible manner. Materials coated on a substrate can be baked across a range of temperatures, allowing multiple experiments to be run in parallel. Combining orthogonal TGP bakes creates a matrix of temperature pairs on a single wafer, allowing two bake step processes to be studied in a single experimental run. Experimental results demonstrating a variety of resist studies are described, including resist CD temperature dependence, underlayer cure temperature determination, and two bake step interactions.

Larson, Carl E.; Wallraff, Gregory M.

2004-05-01

333

Studying lightning strikes  

NASA Astrophysics Data System (ADS)

Scientists studying thunderstorms hope that using an “uninhabited aerial vehicle,” or UAV will allow them to overcome speed limitations of conventional aircraft to gain a better understanding of weather data and forecasting.Researchers with the Altus Cumulus Electrification Study (ACES) say that the Altus UAV flies at between 129 and 185 kilometers per hour, slower than conventional aircraft. This should allow the 55-foot wingspan vehicle to provide a longer-duration picture of thunderstorms without putting pilots and airborne researchers at risk during an August field campaign, based out of Naval Air Station Key West in Florida.

Showstack, Randy

334

Morphing Terminology Study  

SciTech Connect

This study investigates methods of automatically identifying and characterizing significant transitions in term usage over time. Within scientific literature, the occurrence of terms reflects the use of technologies and techniques as well as the study of specific species and materials. Transitions in terminology usage may be a result of vocabulary standardization or specialization in which terms are replaced with their shorter form. They may also be a result of new applications, combinations, alternatives, or interests that result in the appearance of new or existing terminology in unexpected contexts.

Rose, Stuart J.; Brockman, Fred J.; Hart, Michelle L.; Engel, David W.; Valentine, Nancy B.; Calapristi, Augustin J.

2010-06-28

335

Study of genital lesions.  

PubMed

A total of one hundred patients (75 males and 25 females) age ranged from 17-65 years with genital lesions attending the STD clinic of Bowring and LC Hospitals Bangalore constituted the study group. Based on clinical features, the study groups were classified as syphilis (39), chancroid (30), herpes genitalis (13), condylomato lato (9), LGV (7t condylomata acuminata (5), genital scabies (3), granuloma inguinole (2) and genital candidiasis (1). In 68% microbiological findings confirmed the clinical diagnosis. Of the 100 cases 13% and 2% were positive for HIV antibodies and HbsAg respectively. PMID:17642854

Anand Kumar, B H; Vijaya, D; Ravi, R; Reddy, R R

336

Case studies in reproducibility.  

PubMed

Reproducible research is a concept of providing access to data and software along with published scientific findings. By means of some case studies from different disciplines, we will illustrate reasons why readers should be given the possibility to look at the data and software independently from the authors of the original publication. We report results of a survey comprising 100 papers recently published in Bioinformatics. The main finding is that authors of this journal share a culture of making data available. However, the number of papers where source code for simulation studies or analyzes is available is still rather limited. PMID:21278369

Hothorn, Torsten; Leisch, Friedrich

2011-01-28

337

Amtrak fuel consumption study  

SciTech Connect

This report documents a study of fuel consumption on National Railroad Passenger Corporation (Amtrak) trains and is part of an effort to determine effective ways of conserving fuel on the Amtrak system. The study was performed by the Transportation Systems Center (TSC). A series of 26 test runs were conducted on Amtrak trains operating between Boston, Massachusetts, and New Haven, Connecticut, to measure fuel consumption, trip time and other fuel-use-related parameters. The test data were analyzed and compared with results of the TSC Train Performance Simulator replicating the same operations.

Hitz, J.

1981-02-01

338

Pathology Case Study: Dysphagia  

NSDL National Science Digital Library

The University of Pittsburgh School of Medicine's Department of Pathology has compiled a series of case studies to help both students and instructors. The patient in this particular case is a 64-year-old male with difficulty swallowing anything other than liquids. Patient history and both the gross and microscopic descriptions, which include images, are included in this case study. The contributing doctors provide a detailed discussion of the patientâÂÂs condition in the âÂÂFinal Diagnosisâ section. Students will find this resource especially helpful, as it provides experience with patient history, lab results, and diagnostics.

Barnes, Leon, 1941-; Fusco, Gregory P.; Perez, Mia C.

2009-08-25

339

Center for Nonlinear Studies  

NSDL National Science Digital Library

The Los Alamos National Laboratory provides the Center for Nonlinear Studies (CNLS) Website. The goals of the center are "to identify and study fundamental nonlinear phenomena and promote their use in applied research and to stimulate interdisciplinary research and information exchanges inside and outside the laboratory." Research topics include molecular dynamics, patterns in turbulence, stochastic dynamics, combinatorial optimization, and condensed matter, among others. Those interested in supercomputing will want to visit the section dedicated to Avalon, the CNLS supercomputer that is being used for applications ranging from astrophysics to molecular dynamics. Also at the Website, users may access information pertaining to jobs, meetings, talks, and papers.

Center for Nonlinear Studies (Los Alamos National Laboratory).

1999-01-01

340

Center for Nonlinear Studies  

NSDL National Science Digital Library

The Los Alamos National Laboratory provides the Center for Nonlinear Studies (CNLS) Website. The goals of the center are "to identify and study fundamental nonlinear phenomena and promote their use in applied research and to stimulate interdisciplinary research and information exchanges inside and outside the laboratory." Research topics include molecular dynamics, patterns in turbulence, stochastic dynamics, combinatorial optimization, and condensed matter, among others. Those interested in supercomputing will want to visit the section dedicated to Avalon, the CNLS supercomputer that is being used for applications ranging from astrophysics to molecular dynamics. Also at the Website, users may access information pertaining to jobs, meetings, talks, and papers.

Center for Nonlinear Studies (Los Alamos National Laboratory).

2005-10-31

341

STUDY ON DAYLIGHT OBSTRUCTIONS  

Microsoft Academic Search

Based on computer simulation, it has been studied the impact of obstructions (small, medium and large) combined with several other aspects (CIE sky types, windows orientation, dimensions and positions, glazing characteristics) on daylight average illuminance in an office. The results show important drops in average illuminance till 60%, which is a factor of concern for offices real illuminance, in the

Dorin BEU; Florin POP

342

Native American Case Studies  

NSDL National Science Digital Library

The Native American Case Studies collection includes more than 80 original, research-based teaching cases focusing on contemporary issues in Indian Country. Teaching notes accompany each case. These can be downloaded and used at no cost. Additional website resources include information on teaching with cases and assessment. Guidelines for submitting cases are also available.

College, The E.; College, Northwest I.; College, Salish K.; College, Grays H.

343

Capital Financing Study.  

National Technical Information Service (NTIS)

The adequacy of sources of capital for hospital construction and the options open to the federal government regarding hospitals' access to capital were analyzed for the period 1973-1983. The focus of the study was on voluntary non-profit hospitals through...

1973-01-01

344

Skid Tester Correlation Study.  

National Technical Information Service (NTIS)

A correlation study was conducted between the California Skid Tester and an ASTM Skid Tester. Coefficients of friction were obtained with the California unit at the standard test conditions of locked wheel, smooth tire, wet pavement and a speed of 50 mile...

G. B. Sherman M. H. Johnson G. W. Mann R. R. Svetich

1971-01-01

345

Reservoir stability studies  

Microsoft Academic Search

The objective of the reservoir stability studies project is to develop stability criteria for large underground reservoirs in salt domes, hard rock caverns, and porous rock structures for air storage in utility applications. Because reservoir stability was deemed crucial to commercialization of compressed air energy storage (CAES) systems this project has received major emphasis in the early phases of the

1981-01-01

346

Infrared Dye Laser Study.  

National Technical Information Service (NTIS)

Building on work done in Phase I of this study (See AD-748 863), research on near-infrared dye lasers continued along several lines. Eighteen more Kodak organic dyes were screened for laser action using a linear flash lamp for excitation. Six dyes lased b...

B. E. Plourde J. P. Webb

1973-01-01

347

Recon Study Hurricane Agnes.  

National Technical Information Service (NTIS)

The major objective of this study was to make a preliminary overview analysis of the ecological impact of Hurricane Agnes on inland areas of short (up to 1 year), intermediate (1 to 2 years), and long term (beyond 2 years) effects. The following factors w...

1972-01-01

348

Study Skills. Test Taking.  

ERIC Educational Resources Information Center

|Developed as part of the ABCs of Construction National Workplace Literacy Project, this instructional module contains materials designed to help students develop study and test-taking skills. Presented first are 10 strategies for preparing for tests. Discussed next are test-taking strategies and the importance of self-talk in successful test…

Atkinson, Rhonda; And Others

349

Outdoor Unified Studies.  

ERIC Educational Resources Information Center

|Escalante (Utah) High School's outdoor unified studies field trip is a learning experience to be remembered. The four-day camping experience begins with pre-trip plans, pretests, and lecture/introductions to the Anasazi culture and to geologic formations to be visited. Horses (and equipment-carrying trucks) take the students into the desert to…

Liston, Louise

350

Large shaft development study  

SciTech Connect

The purpose of this study is to determine the largest diameter shaft that can be drilled at Hanford utilizing drilling equipment currently on-site, in a single pass, with reasonable assurance of success. Also addressed are such related considerations as circulation systems, bit design, cutter design and configuration, weight on bit, and overall drill penetration rates. 4 refs., 1 tab.

McKinney, S.M. (Morrison-Knudsen Co., Inc., Richland, WA (USA))

1984-09-20

351

Antenna Array Element Study.  

National Technical Information Service (NTIS)

An investigation and analytical study of antenna array elements is being carried out to determine the influence of an individual element of specific characteristics on the performance of an array and, on the basis of element performance, to present data w...

M. B. Haslam

1966-01-01

352

General Aviation Manpower Study.  

ERIC Educational Resources Information Center

Highlights a study examining manpower supply/demand in general aviation. Eight job categories were examined: pilots, flight instructors, engineers, machinists/toolers, and A&P, airframe, and avionics technicians. Findings among others indicate that shortages in indicated job categories exist because personnel are recruited by other industries. (JN)

Feller, Richard

1982-01-01

353

Electroencephalographic Studies of Sleep.  

National Technical Information Service (NTIS)

Various experimental studies on sleep are described. The following areas are discussed: (1) effect of altered day length on sleep, (2) effect of a partial loss of sleep on subsequent nocturnal sleep; (3) effect of rigid control over sleep-wake-up times; (...

W. B. Webb H. W. Agnew

1975-01-01

354

Communication & Media Studies  

Microsoft Academic Search

The Communication & Media Studies Division is one of the growing academic divisions at Cornerstone. We are passionate about instructing, equipping, and mentoring students who we can empower to engage the marketplace of ideas in creative and strategic ways as they take their graduation portfolios into their first jobs as skilled agents of reconciliation in their spheres of influence. Our

David R. Anderson

355

Advanced commercial tokamak study  

SciTech Connect

Advanced commercial tokamak studies were performed by the Fusion Engineering Design Center (FEDC) as a participant in the Tokamak Power Systems Studies (TPSS) project coordinated by the Office of Fusion Energy. The FEDC studies addressed the issues of tokamak reactor cost, size, and complexity. A scoping study model was developed to determine the effect of beta on tokamak economics, and it was found that a competitive cost of electricity could be achieved at a beta of 10 to 15%. The implications of operating at a beta of up to 25% were also addressed. It was found that the economics of fusion, like those of fission, improve as unit size increases. However, small units were found to be competitive as elements of a multiplex plant, provided that unit cost and maintenance time reductions are realized for the small units. The modular tokamak configuration combined several new approaches to develop a less complex and lower cost reactor. The modular design combines the toroidal field coil with the reactor structure, locates the primary vacuum boundary at the reactor cell wall, and uses a vertical assembly and maintenance approach. 12 refs., 19 figs.

Thomson, S.L.; Dabiri, A.E.; Keeton, D.C.; Brown, T.G.; Bussell, G.T.

1985-12-01

356

Power system commonality study  

Microsoft Academic Search

A limited top level study was completed to determine the commonality of power system\\/subsystem concepts within potential lunar and Mars surface power system architectures. A list of power system concepts with high commonality was developed which can be used to synthesize power system architectures which minimize development cost. Examples of potential high commonality power system architectures are given in this

Franklin D. Littman

1992-01-01

357

SCIENCE PERIODICALS USE STUDY  

Microsoft Academic Search

A two-semester study of science periodicals usage at State University of New York at Albany was conducted to identify little used titles for storage or possibly discard. Even in this large multidisciplinary collection a small core of journals accounted for a large percentage of use. Use patterns over time were also recorded and are reported for selected titles. Use rankings

Barbara A. Rice

1979-01-01

358

Subaltern Studies: A Bibliography  

NSDL National Science Digital Library

Compiled by Henry Schwarz and enhanced by Frank Conlon, this bibliography offers an excellent starting point for graduate students or non-specialists interested in this sub-field of Asian studies. The bibliography is a collaborative product consisting of titles suggested to Schwarz by various H-Asia members. Originally created in 1996, the bibliography has been recently updated.

Krishnan, Shekhar.; Conlon, Frank F.; Schwarz, Henry.

1996-01-01

359

Behavioral Study of obedience  

Microsoft Academic Search

This articles describes a procedure for the study of destructive obedience in the laboratory. It consists of ordering a naive S to administer increasingly more severe punishment to a victim in the context of a learning experiment. Punishment is administered by means of a shock generator with 30 graded switches ranging from Slight Shock to Danger: Severe Shock. The victim

Stanley Milgram

1963-01-01

360

Racer efficacy study  

Technology Transfer Automated Retrieval System (TEKTRAN)

Racer (ammonium nonanoate) is a non-selective contact herbicide that controls several weed species. Racer has been labeled by EPA in the past year for weed control in food crops and is close to receiving approval for use by organic producers. The objective of this study was to verify results from ...

361

DWPF Welder Parametric Study  

Microsoft Academic Search

After being filled with glass, DWPF canistered waste forms will be welded closed using an upset resistance welding process. This final closure weld must be leaktight, and must remain so during extended storage at SRS. As part of the DWPF Startup Test Program, a parametric study (DWPF-WP-24) has been performed to determine a range of welder operating parameters which will

Plodinec

1998-01-01

362

Soil Stabilization Study.  

National Technical Information Service (NTIS)

This report concerns a laboratory study of the stabilization of soils from the Red River Valley and South-western North Dakota. Stabilizing treatments were Portland cement, hydrated high-calcium and dolomitic lime, high calcium lime and flyash, high calci...

O. E. Manz

1969-01-01

363

Pangnirtung: A Community Study.  

ERIC Educational Resources Information Center

|This booklet provides reference materials for teachers of social studies in the Northwest Territories (Canada). The information was gathered during workshops attended by elders, community representatives, and teachers from the region. A geography section describes the location of Pangnirtung on Baffin Island and the geology, climate, vegetation,…

Benyk, Pearl, Ed.

364

Soil washing treatability study  

SciTech Connect

Soil washing was identified as a viable treatment process option for remediating soil at the FEMP Environmental Management Project (FEMP). Little information relative to the specific application and potential effectiveness of the soil washing process exists that applies to the types of soil at the FEMP. To properly evaluate this process option in conjunction with the ongoing FEMP Remedial Investigation/Feasibility Study (RI/FS), a treatability testing program was necessary to provide a foundation for a detailed technical evaluation of the viability of the process. In August 1991, efforts were initiated to develop a work plan and experimental design for investigating the effectiveness of soil washing on FEMP soil. In August 1992, the final Treatability Study Work Plan for Operable Unit 5: Soil Washing (DOE 1992) was issued. This document shall be referenced throughout the remainder of this report as the Treatability Study Work Plan (TSWP). The purpose of this treatability study was to generate data to support initial screening and the detailed analysis of alternatives for the Operable Unit 5 FS.

Krstich, M.

1995-12-01

365

Cesium Vapor Cathode Study.  

National Technical Information Service (NTIS)

Cesium-plasma cathodes have been studied as sources of very high-density electron beams. The commonemitter type of cathode using a highly directed cesiumvapor flow has been used to obtain a beam with a density of 800 A/sq cm. The beam was accelerated to 1...

A. E. Eichenbaum F. H. Norman H. Sobol S. Bloom

1965-01-01

366

Major Trauma Outcome Study.  

National Technical Information Service (NTIS)

The American College of Surgeons Committee on Trauma (ASCOT) Major Trauma Outcome Study (MTOS) began in 1982. Since then, more than 150 institutions have submitted data on more than 175,000 patients giving MTOS the largest contemporary description of inju...

C. Frey H. R. Champion

1991-01-01

367

Resources for Women's Studies.  

ERIC Educational Resources Information Center

Over 120 bibliographies and other reference sources relevant to women's studies are identified in this annotated listing. Subjects include feminist scholarship, women in management, popular culture, autobiographies, other cultures and countries, history, lesbian women, women's education, the arts, politics, and rape. In addition to author, title,…

Ridinger, Robert B.

368

Social Studies Journal, 2003.  

ERIC Educational Resources Information Center

This theme issue of the "Social Studies Journal" focuses on the worldwide conflict known in the United States as the French and Indian War (1754-1763). The volume is dedicated to examining the conflict in Pennsylvania. Western Pennsylvania became a battle-scarred landscape as the British and French, with their Native American allies, struggled for…

West, Leo R., Ed.

2003-01-01

369

A Feasibility Study.  

National Technical Information Service (NTIS)

A feasibility study has produced a sporozoite-induced rodent malaria test system that is based on the mortality rather than on the morbidity of negative controls. The test is performed with the NK65 strain of Plasmodium berghei, Anopheles stephensi and IC...

D. S. Rane

1975-01-01

370

The Study of Education.  

ERIC Educational Resources Information Center

|This paper examines several approaches to the study of the foundations of education and rejects all of them. Approaches are classified as "system-adaptive" or "system-reform" according to whether they examine existing educational systems and objectively analyze alternatives or whether they advocate specific new values or, indeed, freedom from all…

Levit, Martin

371

Autism\\/excel study  

Microsoft Academic Search

Five high school students with ASD (autistic spectrum disorder) participating in the Excel\\/Autism study were able to demonstrate mastery of a set of Excel topics. The Excel curriculum covered approximately the same topics as are covered in the Excel portion of Computer Business Applications, a class for regular education students at Fox Chapel Area High School, a high school in

Mary Hart

2005-01-01

372

Plants Study Guide.  

ERIC Educational Resources Information Center

|This study quide is intended to provide students with information about the types and functions of plants, along with some individual learning activities. The guide contains sections about: (1) the contributions of plants to life on earth and the benefits they afford to humanity; (2) the processes of photosynthesis and respiration; (3) the flow…

Brynildson, Inga

373

MR harmonic quad study  

SciTech Connect

To understand the effect of Main Ring harmonic quadruple correctors. Previous data taken with the harmonic quads did not agree well with the SYNCH calculation. The ultimate goal of this study was to be able to change the harmonic quads and verify the changes in lattice function.

Yang, M.-J.; /Fermilab

1995-01-01

374

CTR plasma engineering studies  

NASA Astrophysics Data System (ADS)

Ash (e.g., thermalized helium from D-T) buildup in a tokamak can potentially prevent ignition and seriously degrade the fusion energy gain from driven system. This problem is most pronounced as the ratio of particle/energy confinement time increases towards the neoclassical limit. Yet much improved confinement of the fuel ions is desirable for a fusion reactor. The goals of the work described here were two fold: to study the effect of helium buildup on the energy balance for a tokamak, and consider methods of active control that might be employed to alleviate the problem. We examine ash buildup effect for both D-T and D-(3)He systems. Most examples used apply to the ARIES 1 D-T reactor design and to the ARIES 3 D-(3)He design since part of this was in support of these two designs. Then we report on brief studies of two potentially attractive control methods, namely controlled sawtooth and fishbone instabilities. The concept is that sawteeth or fishbones would be used on purpose periodically in order to 'flush' out excess ash from the fusion core. Both methods are shown to feasible and attractive. More study is needed, however, since the phenomenona are physically complex. Still the pay off, namely, reduced ash buildup, is important so such studies deserves strong attention.

Miley, George H.

375

Plant Study Guide.  

ERIC Educational Resources Information Center

|Appropriate for secondary school botany instruction, this study guide focuses on the important roles of plants in human lives. Following a rationale for learning the basic skills of a botanist, separate sections discuss the process sunlight undergoes during photosynthesis, the flow of energy in the food chain, alternative plant lifestyles, plant…

Brynildson, Inga

376

CFBC ash hydration studies  

Microsoft Academic Search

Hydration studies on CFBC ashes have shown that the acetone technique to prevent hydration in stored samples is relatively effective, only allowing some slight degree of hydration over days in the presence of excess water. In the presence of large excesses of water sufficient to control temperature increases, the degree of bulk mixing has no effect on the degree of

Edward J. Anthony; Lufei Jia; Yinghai Wu

2005-01-01

377

What is Development Studies?  

Microsoft Academic Search

This article is concerned with some initial reflections on the distinctive features of Development Studies (DS). The aim is to trigger further debate, rather than attempt ‘closure’. Discussion of the nature of DS is timely because of the expansion of taught courses at various levels during the previous decade; because of sustained critiques of DS in recent years; and because

Andrew Sumner

2006-01-01

378

Applied Music (Individual Study).  

ERIC Educational Resources Information Center

Background information and resources to help students in grades 9-12 in Texas pursue an individual study contract in applied music is presented. To fulfill a contract students must publicly perform from memory, with accompaniment as specified, three selections from a list of approved music for their chosen field (instrument or voice). Material…

Texas Education Agency, Austin.

379

Recycling Study Guide.  

ERIC Educational Resources Information Center

This study guide was designed to help teachers and students understand the problems surrounding solid wastes. It includes an overview of solid waste and recycling, a glossary, suggested activities and a list of resource publications, audiovisual materials and organizations. There are 19 activity suggestions included in this guide designed for use…

Hallowell, Anne; And Others

380

Geostatistical case studies  

Microsoft Academic Search

The objective of this volume of contributed chapters is to present a series of applications of geostatistics. These range from a careful variographic analysis on uranium data, through detailed studies on geologically complex deposits, right up to the latest nonlinear methods applied to deposits with highly skewed data contributions. Applications of new techniques such as the external drift method for

G. Matheron; M. Armstrong

1987-01-01

381

CCD Signal Processor Study.  

National Technical Information Service (NTIS)

This report presents the results of a study of the application of charge coupled devices (CCD's) to radar signal processing systems. The particular radar problem considered was the detection of satellites at ranges of up to 25,000 NM. A CCD baseline desig...

L. W. Martinson B. P. Gaffney G. J. Mayer

1977-01-01

382

Gloved Operator Performance Study.  

National Technical Information Service (NTIS)

This study is to determine whether greater minimum spacing is required between push buttons for gloved operation than for bare-handed operation. Seventy-two undergraduate students served as subjects in groups of 12, one group for each of the six hand-wear...

J. Berkhout G. Anderson M. McCleerey M. Granaas

1992-01-01

383

The Zurich study  

Microsoft Academic Search

Hypomania in a 28- to 30-year-old cohort is described. Data were taken from a prospective longitudinal cohort study from the general population of Zurich, Switzerland. An estimated 1-year prevalence rate of hypomania of 4% was found. Over a period of time hypomania was associated with major depression and dysthymia. We found equal proportions of suicide attempts and equal rates of

W. Wicki; J. Angst

1991-01-01

384

The Zurich Study  

Microsoft Academic Search

Summary A prospective study of depressive syndromes and diagnoses was performed among a young adult Swiss population with three interviews over 7 years. Different definitions of depressive states were used: on the one hand, depressive syndromes including mood disturbances of any severity, on the other, well-defined diagnoses of depression. Women were consistently overrepresented among subjects with depressive syndromes of some

C. Ernst; J. Angst

1992-01-01

385

The zurich study  

Microsoft Academic Search

This study describes sleep behaviour and insomnia in a representative cohort of a Swiss population. Interviews were carried out prospectively from age 20–21 to 27–28 years, starting with 292 males and 299 females. Females usually go to bed earlier and sleep 30 min longer than males. Taking into account length and periodicity of insomnia we can distinguish occasional insomnia (OI),

J. Angst; M. Vollrath; R. Koch; A. Dobler-Mikola

1989-01-01

386

The Zurich Study: XXII  

Microsoft Academic Search

A representative cohort of Swiss adults recruited at age 20 years and interviewed at ages 23, 28 and 30 years was studied regarding the symptomatology, prevalence and longitudinal course of functional gastrointestinal symptoms and their association with psychiatric syndromes. A functional gastrointestinal complaint was identified if a proband reported symptoms at least eight times in the past year or for

B. Hochstrasser; J. Angst

1996-01-01

387

The Zurich study  

Microsoft Academic Search

Summary The purpose of this study was to investigate antecedents of first incidence of major depressive disorder and recurrent brief depression with the help of a cohort of 20 year-old Swiss, who was interviewed four times up to age 30. Cases diagnosed as depressed at the third or fourth interview (age 28 or 30) were compared with never diagnosed controls

Cécile Ernst; Gary Schmid; Jules Angst

1992-01-01

388

The Zurich study  

Microsoft Academic Search

The longitudinal study of a cohort of 591 men and women aged 20 and 21 years respectively at outset, and 23\\/24 years at a subsequent investigation, was analyzed for the manifestation of depressive syndromes. The syndromes were grouped according to their duration: 1 week once or twice per year (group B),1 week three or more times per year (C), 2

J. Angst; A. Dobler-Mikola

1984-01-01

389

Teaching Biblical Studies Online  

ERIC Educational Resources Information Center

|In this edited transcript of a panel at the Society of Biblical Literature (November 23, 2009, Boston, Massachusetts), five Bible scholars give brief presentations on various challenges and opportunities encountered when teaching academic biblical studies courses online in both undergraduate and theological education contexts. Each presentation…

Delamarter, Stephen; Gravett, Sandra L.; Ulrich, Daniel W.; Nysse, Richard W.; Polaski, Sandra Hack

2011-01-01

390

Studies in Empowerment.  

ERIC Educational Resources Information Center

This theme issue of the serial "Educational Foundations" contains five articles devoted to the topic of "Studies in Empowerment." In "The Disempowering of Empowerment: Out of the Revolution and into the Classroom," Margaret D. LeCompte and Kathleen Bennett deMarrais focused on placing the term in proper historical context. Guy B. Senese "Away from…

Van Galen, Jane, Ed.; And Others

1992-01-01

391

Electrode Passivation Studies.  

National Technical Information Service (NTIS)

Studies of the passivation of Zn-Fe, Zn-Mn, Zn-Co, and Zn-Ni alloys were made potentiostatically. Alloys of 90 Zn 10 Fe corrode at a high rate even when passive. Alloys of 83Zn-17 Mn have low, active dissolution currents. The 89 Zn - 11 Co alloys have hig...

S. B. Brummer A. C. Makrides J. Bradspies

1966-01-01

392

Asian American Studies.  

ERIC Educational Resources Information Center

|The sociodemographic and socioeconomic characteristics of all Asian American communities since 1950 have been greatly influenced by federal immigration legislation, and it is not possible to consider the field of Asian American studies without an understanding of the history of immigration legislation. Asian American research may be divided into…

Liu, William T.; Yu, Elena S. H.

393

Aircraft EMP Isolation Study.  

National Technical Information Service (NTIS)

This report presents the results of a preliminary study into methods for electrically isolating the E-4B, the EC-135, and the EC-130 aircraft during EMP tests where the aircraft under test is directly driven by a high-voltage pulser.

A. Finci H. Price P. Chao S. Mercer T. Naff

1980-01-01

394

Aircraft EMP isolation study  

Microsoft Academic Search

This report presents the results of a preliminary study into methods for electrically isolating the E-4B, the EC-135, and the EC-130 aircraft during EMP tests where the aircraft under test is directly driven by a high-voltage pulser.

A. Finci; H. Price; P. Chao; S. Mercer; T. Naff

1980-01-01

395

Studies in quantitative inheritance  

Microsoft Academic Search

In the course of a general study of the inheritance of body size in Drosophila melanogaster, by means of selection and chromosome analysis, many crosses have been made between strains and inbred lines of similar and also widely differing body size. In some cases these crosses were more or less incidental to other aspects of the work and this limits

Forbes W. Robertson; E. C. R. Reeve

1955-01-01

396

Reconsidering Social Studies Curriculum.  

ERIC Educational Resources Information Center

Two views of social studies curriculum development are discussed. The technical project view assumes a linear sequence of discrete events; the social process view assumes a dynamic, interactive relationship among policy, planning, enactment, and their sociocultural context. An alternative conception that integrates technical, social, and critical…

Cornbleth, Catherine

1985-01-01

397

Synergistic Navigation System Study.  

National Technical Information Service (NTIS)

Phase I of the Synergistic Navigation Systems Study is a comparison analysis of the cost/effectiveness of various optimal filtering techniques for a Doppler-inertial navigation system with position-fixing. The costs are assessed in terms of program execut...

K. A. Klementis C. J. Standish

1966-01-01

398

Hazardous crater lakes studied  

Microsoft Academic Search

Crater lakes usually sit on top of volcanic conduits and act as condensers of magmatic vapor. Studies of crater lakes can therefore provide information on both deep magmatic activity and variations in the degassing state of a shallow magmatic body. The Lake Nyos gas disaster of August 1986 and a similar event in August 1984 at Lake Monoun, both in

Minoru Kusakabe

1993-01-01

399

Caucasus: Self Study Guide.  

National Technical Information Service (NTIS)

The Self-Study Guide to the Caucasus (Armenia, Azerbaijan, Georgia and certain aspects of the North Caucasus, Russia) is intended to provide U.S. Government personnel in the foreign affairs community with an overview of important issues related to Caucasu...

A. van Oss

2004-01-01

400

Soviet Seismicity Study.  

National Technical Information Service (NTIS)

A working INGRES database 'sov' has been established at the Center for Seismic Studies which contains the seismicity data reported in the annual Soviet publications, 'Earthquakes in the USSR in 1973', etc. for the 1973 through 1979 time period. The total ...

W. Helterbran

1985-01-01

401

Subway Tunnel Energy Study.  

National Technical Information Service (NTIS)

The idea of the Subway Tunnel Energy System was conceived by Joel Levinson of Levinson Zaprauskis Associates (LZA), and proposed to the City of Philadelphia in 1981. LZA believed that a study of the feasibility of using subway tunnel air as a heat sink/he...

J. Levinson E. Knapp J. Gonzalez E. Douglass

1988-01-01

402

An Ethnic Studies Evolution  

ERIC Educational Resources Information Center

|As a student in the Chicana/o studies program at the University of Texas at El Paso (UTEP), Jesse S. Arrieta decided that her classroom instruction about the culture and history of people of Mexican origin wasn't enough. Arrieta, 27, who graduated from UTEP in 2002 before earning a master's in American history from the University of California,…

Boulard, Garry

2006-01-01

403

Social Studies: Grade 8.  

ERIC Educational Resources Information Center

This Manitoba (Canada) curriculum guide for eighth grade social studies students contains suggested teaching strategies and learning activities in four units covering: (1) life during prehistoric and early historic times; (2) ancient civilizations; (3) life in early modern Europe; and (4) life in the modern world. Each unit includes an overview,…

Manitoba Dept. of Education, Winnipeg.

404

NGLW RCRA Storage Study  

SciTech Connect

The Idaho Nuclear Technology and Engineering Center (INTEC) at the Idaho National Engineering and Environmental Laboratory contains radioactive liquid waste in underground storage tanks at the INTEC Tank Farm Facility (TFF). INTEC is currently treating the waste by evaporation to reduce the liquid volume for continued storage, and by calcination to reduce and convert the liquid to a dry waste form for long-term storage in calcine bins. Both treatment methods and activities in support of those treatment operations result in Newly Generated Liquid Waste (NGLW) being sent to TFF. The storage tanks in the TFF are underground, contained in concrete vaults with instrumentation, piping, transfer jets, and managed sumps in case of any liquid accumulation in the vault. The configuration of these tanks is such that Resource Conservation and Recovery Act (RCRA) regulations apply. The TFF tanks were assessed several years ago with respect to the RCRA regulations and they were found to be deficient. This study considers the configuration of the current tanks and the RCRA deficiencies identified for each. The study identifies four potential methods and proposes a means of correcting the deficiencies. The cost estimates included in the study account for construction cost; construction methods to minimize work exposure to chemical hazards, radioactive contamination, and ionizing radiation hazards; project logistics; and project schedule. The study also estimates the tank volumes benefit associated with each corrective action to support TFF liquid waste management planning.

R. J. Waters; R. Ochoa; K. D. Fritz; D. W. Craig

2000-06-01

405

Floating Object Recovery Study.  

National Technical Information Service (NTIS)

A study was conducted to determine a method to recover floating objects from the surface of the ocean. Model test tank investigations conducted at Stevens Institute of generating a localized flow field which would refract waves were investigated for a pos...

R. J. Helgeson

1970-01-01

406

The JASMINE Pilot Study  

Microsoft Academic Search

The methods and initial results of an extensive pilot study, the Joint Air-Sea Monsoon Interaction Experiment (JASMINE) held in the Indian Ocean during the summer of 1999, are described. The experimental design was based on the precept that the monsoon sways back and forth from active to inactive (or break) phases and that these intraseasonal oscillations are coupled ocean-atmosphere phenomena

P. J. Webster; E. F. Bradley; C. W. Fairall; J. S. Godfrey; P. Hacker; R. A. Houze Jr.; R. Lukas; Y. Serra; J. M. Hummon; T. D. M. Lawrence; C. A. Russell; M. N. Ryan; K. Sahami; P. Zuidema

2002-01-01

407

Biological Studies in Art  

ERIC Educational Resources Information Center

The Biological Studies in Art program offers students at the high school level an unusual opportunity to prepare for a career in biological illustration. This field offers opportunities for employment in museums, publishing houses, and other similar settings. (Author/BB)

Karan, Theodora

1978-01-01

408

Special disarmament study.  

National Technical Information Service (NTIS)

This study investigates the cost of shutting down and later starting up the Hanford production complex. Also included are comments on two aspects, other than cost, which are consider to be of great importance. One is the impact of a complete shutdown on t...

R. Nilson

1967-01-01

409

Breast cancer study.  

PubMed

In the report "Spacelab-2 plasma depletion experiments for ionospheric and radio astronomical studies" by M. Mendillo et al. (27 Nov., p. 1260), figure 5A (p. 1263) was misplaced with respect to figure 5B so that the scale of figure 5A was incorrectly represented. A correct figure 5 is printed below. PMID:3277282

Kuller, L H

1988-02-19

410

Study of Barnacle Cement.  

National Technical Information Service (NTIS)

Gross anatomical studies were done on the giant barnacle Balanus nubilis. This work was aimed at finding the site of cement production and its internal flow path. The internal flow path is a tubular network in the basal mass that communicates with the rad...

D. Lockhart K. Walker T. King R. Keller N. F. Cardarelli

1968-01-01

411

Resources for Women's Studies.  

ERIC Educational Resources Information Center

|Over 120 bibliographies and other reference sources relevant to women's studies are identified in this annotated listing. Subjects include feminist scholarship, women in management, popular culture, autobiographies, other cultures and countries, history, lesbian women, women's education, the arts, politics, and rape. In addition to author, title,…

Ridinger, Robert B.

412

Etiological study of omphalocele  

Microsoft Academic Search

The epidemiological, teratological and genetic data on 134 index patients with omphalocele (79 isolated and 55 multiple ones) and on 134 matched controls born in Hungary 1970–1976 were studied from medical records and by retrospective interview. The stillbirth rate and infant mortality are significantly higher, and there is intrauterine weight retardation and more frequent preterm delivery. The distribution of maternal

A. Czeizel; Márta Vitéz

1981-01-01

413

Foamed Aluminum Propellant Study.  

National Technical Information Service (NTIS)

This report summarizes the results of an AFRPL feasibility study on the use of a new experimental material, foam aluminum. The chief areas of interest center around the value of this material in high-burn-rate, pulse or end-burning motors and high acceler...

B. R. Warren C. G. Bacon

1968-01-01

414

SOLID WASTE STUDY  

SciTech Connect

The purpose of this document is to study the solid waste issues brought about by a Type C Investigation; ``Disposal of Inappropriate Material in the Los Alamos County Landfill'' (May 28, 1993). The study was completed in August 1995 by Coleman Research Corporation, under subcontract number 405810005-Y for Los Alamos National Laboratory (LANL). The study confirmed the issues identified in the Type C investigation, and also ascertained further issues or problems. During the course of this study two incidents involving hazardous waste resulted in the inappropriate disposal of the waste. An accidental spill, on June 8, 1995, at one of Laboratory buildings was not handled correctly, and ended up in the LAC Landfill. Hazardous waste was disposed of in a solid waste container and sent to the Los Alamos County Landfill. An attempt to locate the hazardous waste at the LAC Landfill was not successful. The second incident involving hazardous waste was discovered by the FSS-8, during a random dumpster surveillance. An interim dumpster program managed by FSS-8 discovered hazardous waste and copper chips in the solid waste, on August 9, 1995. The hazardous waste and copper chips would have been transported to the LAC Landfill if the audit team had not brought the problem to the awareness of the facility waste management personnel.

PAUL G. ORTIZ - COLEMAN RESEARCH CORP /COMPA INDUSTRIES

1995-08-01

415

Black Studies Year One.  

ERIC Educational Resources Information Center

|Though Dubois tried to begin a series of scientific studies on the Negro problem in America more than 70 years ago, only recently have attempts been made to present a true history of the Black man in institutions of higher learning. Until that time, the experience of the Black man was defined in Euro-American terms, or in most cases was…

Long, Richard A.

416

Cargo Boom Study.  

National Technical Information Service (NTIS)

A conceptual design study was made to determine the feasibility of a large cargo handling boom with master-slave controls having spatial correspondence and force feedback. Commercial devices of this type have been built which handle loads of up to 800 pou...

D. P. Bodine E. J. Campbell J. B. Makinson P. F. Croshaw R. S. Mosher

1970-01-01

417

Studies in Southwest Spanish.  

ERIC Educational Resources Information Center

The Spanish dialects of the Southwest United States have received little serious attention until recently. The present volume contains studies designed to contribute to the understanding and acceptance of Southwest Spanish. The book consists of the following chapters: (1) "Linguistic Diversity in Southwest Spanish," by Garland D. Bills and Jacob…

Bowen, J. Donald, Ed.; Ornstein, Jacob, Ed.

418

Area Studies: China.  

ERIC Educational Resources Information Center

|The guide outlines a course of study for elementary students on the history, geography, language, and general culture of China. Course objectives are to identify the major mountains, the major cities, and the types of climate affecting each region of China; locate and record on a time line the important events in the development of Chinese…

Blouin, Virginia; And Others

419

Owego Environmental Study.  

National Technical Information Service (NTIS)

The study presents the residents of New York's southern tier town of Owego with a compendium of information regarding their environment, particularly the naturally-occurring and man-made physical resources of the town. Five chapters report on : (I) Invent...

J. Gentili M. J. Lavine

1974-01-01

420

DETROIT CHILDREN'S HEALTH STUDY  

EPA Science Inventory

The Detroit Children's Health Study will consist of health questionnaires for 15,000 children enrolled in the fourth- and fifth-grades of selected elementary schools, and measurements of lung function and exhaled breath in a subset of 3,500 of these children. Participation in bo...

421

Grounding Probability Studies.  

National Technical Information Service (NTIS)

Grounding statistics for vessels over 6000 G.T. were compiled for the 6 years 1970-1975. Results were analyzed for tankers and non-tankers, each in four gross tonnage groups as to location, cause, and result. Groundings were studied in detail on proposed ...

V. U. Minorsky

1977-01-01

422

National Indian Education Study  

ERIC Educational Resources Information Center

This report includes information from the National Indian Education Study of American Indian/Alaska Native students in grades 4 and 8 on the 2005 National Assessment of Education Progress (NAEP) in reading and mathematics. The national sample includes both public and private schools (i.e. Bureau of Indian Affairs, Department of Defense Education…

Harvey, Karen Kay

2006-01-01

423

Micromodel foam flow study  

Microsoft Academic Search

Foams are often utilized as part of enhanced oil recovery techniques. This report presents the results of a micromodel foam flow study. Micromodels are valuable tools in uncovering capillary phenomena responsible for lamellae generation and coalescence during foam flow in porous media. Among the mechanisms observed are snap-off, weeping-flow breakup, and lamella division and leave behind. Coalescence mechanisms include dynamic

K. T. Chambers; C. J. Radke

1990-01-01

424

Ethics and Study Abroad  

ERIC Educational Resources Information Center

|It came as a great surprise recently to read in "The New York Times" that the New York attorney general's office had launched an investigation into possible financial improprieties between colleges and outside organizations that provide study-abroad programs. Subpoenas had been issued to five of the largest program providers, "with more to come."…

Hoffa, William W.

2007-01-01

425

STUDIES IN CHARACTER STRUCTURE  

Microsoft Academic Search

IN A SERIES OF STUDIES IT WAS FOUND THAT SS CLASSIFIED ON THE BASIS OF TEST SCORES AS HIGH IN IMPULSIVITY IN COMPARISON TO THOSE CLASSIFIED AS LOW IN IMPULSIVITY: (1) WERE LESS ACCEPTING OF CONVENTIONAL MIDDLE-CLASS VALUES RELATED TO RULES AND REGULATIONS, (2) OVERESTIMATED THE PASSAGE OF 8 MIN. BY THE METHOD OF PRODUCTION, (3) WERE EASILY INSTIGATED TO

DAVID KIPNIS

1968-01-01

426

Why Indigenous Nations Studies?  

ERIC Educational Resources Information Center

|The development of a new Indigenous Nations Studies program at the University of Kansas is described. Success depended on a critical mass of Indigenous and non-Indigenous faculty and students that had a sense of political and social justice and understood the need for institutional change. The biggest challenge was countering the entrenched…

Porter, Robert; Yellow Bird, Michael

2000-01-01

427

INTRODUCTION AND STUDY DESIGN  

EPA Science Inventory

Under the sponsorship of the UNEP/ILO/IPCS, 17 laboratories from diverse regions of the world participated in evaluating the utility of four plant bioassays for detecting genetic hazards of environmental chemicals. he bioassays included in this collaborative study were Arabidopsi...

428

General Aviation Manpower Study.  

ERIC Educational Resources Information Center

|Highlights a study examining manpower supply/demand in general aviation. Eight job categories were examined: pilots, flight instructors, engineers, machinists/toolers, and A&P, airframe, and avionics technicians. Findings among others indicate that shortages in indicated job categories exist because personnel are recruited by other industries.…

Feller, Richard

1982-01-01

429

Cephradine antacids interaction studies.  

PubMed

The present work comprises of interaction studies of cephradine with antacids. Cephradine is included among the first generation cephalosporin, which is active against a wide range of Gram positive and Gram-negative bacteria including penicillinase-producing staphylococci. Since the presence of complexing ligand may affect the bioavailability of a drug in blood or tissues, therefore, in order to study the probable interaction of cephradine with antacids all the reaction conditions were simulated to natural environments. Antacids are commonly used in patients complaining of GI irritations. The behavior of cephradine in presence of seven antacids i.e., simethicone, magaldrate, magnesium carbonate, magnesium hydroxide, magnesium trisilicate, sodium bicarbonate and aluminium hydroxide was studied by using standard dissolution apparatus. Cephradine was monitored both by UV and by high performance liquid chromatography. The results revealed that antacids containing polyvalent cations retarded the in vitro availability of cephradine. Moreover, these studies indicated that cephradine was strongly adsorbed on antacids; magnesium trisilicate and simeco tablets (powdered) exhibited relatively higher adsorption capacities. PMID:17545100

Arayne, M Saeed; Sultana, Najma; Afzal, M

2007-07-01

430

Neuroimaging studies of priming  

Microsoft Academic Search

This article reviews functional neuroimaging studies of priming, a behavioural change associated with the repeated processing of a stimulus. Using the haemodynamic techniques of functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), priming-related effects have been observed in numerous regions of the human brain, with the specific regions depending on the type of stimulus and the manner in

R. N. A. Henson

2003-01-01

431

Assured Energy Receptivity Study.  

National Technical Information Service (NTIS)

The study objective was to determine the amount of heat removed from rapid transit tunnels by adding wayside resistors which would absorb braking energy that could not be absorbed by normal regeneration. In addition, preliminary design and cost data for t...

1975-01-01

432

Flywheel driving system study.  

National Technical Information Service (NTIS)

A flywheel drive system using AC/DC/AC indirect type power conversion method was studied in this paper. The VSC controls the converter input current so as to supply active and reactive power to the utility and load at the same time. The VSI operate as VVV...

J. H. Choi H. M. Jeoung B. G. Lee

1997-01-01

433

Vietnam Nurse Health Study.  

National Technical Information Service (NTIS)

The purpose of this study was to identify and compare the health problems and reproductive outcomes of three groups of women: Theater veterans were defined as members of the Armed Forces of the United States who served as nurses in Vietnam. Era veterans w...

2004-01-01

434

Studies in Manpower Planning.  

ERIC Educational Resources Information Center

|This compilation consists of a collection of reports on models and studies in the area of manpower management and planning. Part One contains a doctoral dissertation, "The Application of Computer-Assisted Multi-Level Manpower Planning Models in the Federal Government" by R. J. Niehaus, which provides a comprehensive summary of the U.S. Navy's…

Charnes, A.; And Others

435

Minority Work Study Program.  

ERIC Educational Resources Information Center

This report covers a work-study program in the East-West Gateway area to provide employment and training for minority and economically disadvantaged graduate and upper-division undergraduate students enrolled in planning and related curricula. The program has aided students in continuing their education who might otherwise be financially unable to…

East-West Gateway Coordinating Council, St. Louis, MO.

436

Groves Model Accuracy Study.  

National Technical Information Service (NTIS)

USAFETAC was tasked to review the scientific literature for studies of the Groves Neutral Density Climatology Model and compare the Groves Model with others in the 30-60 km range. The tasking included a request to investigate the merits of comparing accur...

M. C. Peterson

1991-01-01

437

Sweden's largest Facebook study  

Microsoft Academic Search

The emergence of the Internet has made it easier for people to socially interact than ever before. Today, the most popular channel is Facebook with over 845 million users world wide. In Sweden, the number of users amount to approximately half of the population. We had two aims with this study. First, we investigate which areas of Facebook usage that

Leif Denti; Isak Barbopoulus; Ida Nilsson; Linda Holmberg; Magdalena Thulin; Malin Wendeblad; Lisa Andén; Emelie Davidsson

2012-01-01

438

TRAHC Folklife Study Guides.  

ERIC Educational Resources Information Center

Each of the seven study guides combined in this packet provides a lesson that includes a reading or descriptive narrative of the topic, along with teaching objectives, questions to consider, and suggested classroom activities. Topics covered are: (1) "Introduction to the Concept of Folklife"; (2) "Southern Gospel Music and Song"; (3) "No Brag,…

Texarkana Regional Arts and Humanities Council, Inc., TX.

439

Sert D Spacecraft Study.  

National Technical Information Service (NTIS)

The SERT D (Space Electric Rocket Test - D) study defines a possible spacecraft project that would demonstrate the use of electric ion thrusters for long-term (5 yr) station keeping and attitude control of a synchronous orbit satellite. Other mission obje...

1974-01-01

440

Waterbirths: A Comparative Study  

Microsoft Academic Search

Background: Waterbirths were introduced in 1991 as part of a new birth concept which consisted of careful monitoring and birth management, restrictive use of invasive methods and free choice of different birth methods. Methods: After the introduction of this new birth concept a prospective observational study was initiated. All parturients of the region give birth in our clinic without preselection,

Verena Geissbühler; Jakob Eberhard

2000-01-01

441

Recent Studies in Autism  

Microsoft Academic Search

The syndrome of infantile autism is briefly described and the development of knowledge regarding its symptomatology traced from Kanner's first description to Ornitz' division of symptoms into subclusters. Theories of etiology are discussed and experimental studies are reviewed in the areas of cerebral lateralization, brainstem transmission time, and vestibular function. Theories discussing the site of suspected dysfunction within the central

Theodore W. Peterson

1986-01-01

442

Pozzolan Cement Study.  

National Technical Information Service (NTIS)

This research study was to evaluate the performance of a Type 1P cement concrete pavement constructed on an experimental project as compared to a regular Type 1(B) cement concrete pavement. The sections were evaluated for strength, durability, skid resist...

S. M. Law M. Rasoulian

1979-01-01

443

Reservoir Impact Study.  

National Technical Information Service (NTIS)

Completed in 1964, Canyon Dam in Comal County, Texas, impounds the only large reservoir in the Guadalupe River drainage. In a study of the decision and impact history of this water-development project, it was found that the principal beneficiaries paid li...

E. Cook R. C. Schaffer D. D. Baumann B. W. Cain R. A. Clark

1974-01-01

444

Agricultural Health Study  

Cancer.gov

A prospective cohort study of commercial pesticide applicators, farmers and farmers' spouses in Iowa and North Carolina conducted in collaboration among the National Cancer Institute, the National Institute of Environmental Health Sciences, the U.S. Environmental Protection Agency and the National Institute for Occupational Safety and Health. 

445

Social Studies: Grade 8.  

ERIC Educational Resources Information Center

|This Manitoba (Canada) curriculum guide for eighth grade social studies students contains suggested teaching strategies and learning activities in four units covering: (1) life during prehistoric and early historic times; (2) ancient civilizations; (3) life in early modern Europe; and (4) life in the modern world. Each unit includes an overview,…

Manitoba Dept. of Education, Winnipeg.

446

Studying for social work  

Microsoft Academic Search

This essential guide to study skills takes social work students through every step of their degree journey, providing them with the academic tools they will need to thrive along the way. Inventively informed by the insights and reflections of qualifying students, the book offers effective guidance that is grounded in real experience of the social work degree. It is particularly

Eileen Baldry; Mark Hughes; Linda Burnett; Ian Collinson

2011-01-01

447

Adoption Home Study Process  

MedlinePLUS

... department of social services) may not charge a fee for the home study. If these agencies do charge a fee, they often are modest ($300 to $500), and ... you adopt a child from foster care the fee is usually reimbursed. A private agency or certified ...

448

Tire footprint studies  

NASA Astrophysics Data System (ADS)

This presentation covers the results of tire footprint studies conducted in the Landing Gear Development Facility of the USAF Wright Laboratory at the Wright Patterson Air force Base, OH. Tire footprint studies are essential in understanding tire wear mechanisms and computing tire tread wear rates. The power input into the tread is the driving force for tread wear. Variables needed for power input calculations include the footprint pressure and slip velocity distributions. Studies were performed on the effects of power input distributions due to vertical load, camber, yaw, inflation pressure, and tire construction. For the present study, two tire constructions, one radial and the other bias, were selected. These tires were for the F-16 Block 30 fighter aircraft, both of which were previously worn. The present study was limited to steady straight roll with a 14,000 lb vertical load, a 310 psi inflation pressure, and zero yaw and camber. All tests were conducted on the Tire Force Machine (TFM) with a specialized sensor plate with embedded pressure sensors (X, Y, and Z) and slip sensors (X and Y). All tests were conducted for a table speed of 1 in/s. Tests on the TFM show that the power intensity distributions and total power for both tire constructions are quite similar for straight roll. Later on, tests were also conducted on a modified dynamometer which was overlaid with a grit wear surface. The tire speed was maintained at 40 miles per hour and yaw was set to four degrees. Dynamometer tests showed that radial tires have more tread wear than the bias tire; however, in the field, radial tires have longer life.

Chawla, Mangal; Medzorian, John

1995-08-01

449

Study of QCD Confinement  

NASA Astrophysics Data System (ADS)

Substantial numerical studies on pure lattice gauge theory have shown that the non-Abelian gauge theory is permanently confined at zero temperature and undergoes a deconfining phase transition at very high temperature. This thesis, however, is dedicated to the analytical study of the pure lattice gauge theory. Our focus is also on the confinement property of the gauge fields. This study is motivated by the effective spin model approach developed by Svetitsky and Yaffe. By using a variational principle, we have derived exactly the d dimensional effective spin model from the d + 1 dimensional SU(N) gauge theory for both zero and finite temperature cases. For both cases, the dynamics is rather simple: only nearest neighbor coupling exists. Therefore our effective spin model provides a competitive model for the study of the QCD vacuum properties. Based on our zero temperature effective spin model, our analysis shows that if the gauge field is confined, the quark anti-quark potential must be linear, which confirms the string picture of confinement. The 1 + 1 dimensional SU(2) gauge field theory has been solved exactly and its confinement is trivially confirmed. In particular, we have shown that in this case the Polyakov quark potential is equivalent to the Wilson potential. This strongly supports the conjecture that the definitions of the quark potential by Wilson and Polyakov are equivalent. We have also shown that our approach has the (tantalizing) potential to solve the confinement problem for 3 + 1 dimensional non-Abelian gauge fields. Finally, the 3 dimensional finite temperature effective spin model has also been investigated. We showed explicitly that the SU(2) gauge field undergoes second and SU(N) (N > 3) first order deconfining phase transitions. The deconfining phase transition temperature has also been studied for SU(2) gauge field by using the variational cumulant expansion method. The results are rather satisfactory.

Zhu, Zheng-Kun

1995-01-01

450

Photovoltaic evaluation study  

NASA Astrophysics Data System (ADS)

Realizing the value and potential of PV-power as well as the growing need for increased cooperation and sharing of knowledge in the field of photovoltaics, FINNIDA and UNICEF decided to undertake a study of selected PV-projects. There were two main objectives for the study: To gather, compile, evaluate and share information on the photovoltaic technology appropriate to developing countries, and to promote the interest and competence of Finnish research institutes, consultants and manufacturers in photovoltaic development. For this purpose a joint evaluation of significant, primarily UN-supported projects providing for the basic needs of rural communities was undertaken. The Gambia and Kenya offered a variety of such projects, and were chosen as target countries for the study. The projects were chosen to be both comparable and complimentary. In the Gambia, the main subject was a partially integrated health and telecommunications project, but a long-operating drinking water pumping system was also studied. In Kenya, a health project in the Turkana area was examined, and also a large scale water pumping installation for fish farming. Field visits were made in order to verify and supplement the data gathered through document research and earlier investigations. Individual data gathering sheets for the project form the core of this study and are intended to give the necessary information in an organized and accessible format. The findings could practically be condensed into one sentence: PV-systems work very well, if properly designed and installed, but the resources and requirements of the recipients must be considered to a higher degree.

Johnson, G.; Heikkilae, M.; Melasuo, T.; Spanner, S.

451

[Twin studies in psychiatry].  

PubMed

Twin research in medicine and psychology has blossomed during the last decades. A brief presentation of twin research methods is given, followed by a review of psychiatric studies, particularly Norwegian ones. The Nordic investigations are of great importance because many of these studies have been able to avoid shortcomings in sampling by linking national twin registers to disease registers. This procedure is of consequence for the estimation of heritability. Twin research shows that the genetic contribution to Alzheimer's disease, manic-depressive (bipolar) disorder, schizophrenia and childhood autism is relatively strong, whereas genetic factors play a minor role in common depressions, anxiety and somatoform disorders, and alcohol abuse. Since the concordance rates are far from 100 percent in most of these illnesses, environmental factors must also be important. PMID:10533417

Kringlen, E

1999-09-20

452

Ferrocyanide safety study  

SciTech Connect

The overall objective of this study is to investigate the potentially rapid reactions between the ferrocyanide-containing salts, present in the SST's, and oxidants, such as nitrate, also present in the SST's. The objective of the energetics subtask is to investigate, on a screening basis, SST operational and compositional parameters which could affect the reaction between nickel cesium ferrocyanide, the expected form of cyanide in the SST, and nitrates and/or the nitrate radiolysis product nitrite. The objective of the large-scale explosion study is to independently confirm the results of the PNL laboratory-scale experiments and to determine the explosive behavior of a large sample of ferrocyanide and oxidant. The objective of the PNL-5441 revision subtask is to revise the complexant stability report, PNL-5441, to provide a current overview of the ferrocyanide safety issue and provide information to permit establishment of guidelines for SST management. 1 fig.

Wegeng, R.S.

1989-05-01

453

Alcohol Studies Database  

NSDL National Science Digital Library

Since 1987, staff members at the Rutgers University Center of Alcohol Studies have been collecting citations of documents related to alcohol. Today, they have over 80,000 citations and much of the material is related to research and professional materials that deal with the subject. Additionally, the database contains a small collection of educational and prevention materials designed for use by educators, parents, and public health workers. The site is maintained by the Scholarly Communication Center, the Center of Alcohol Studies, and the Rutgers University Libraries. Visitors to the site can search by subject, or perform a more advanced search as well. The site also includes a "Help" area, which includes information on limiting searches, links to full text, and suggestions on using Boolean techniques.

454

NASA study grants  

NASA Astrophysics Data System (ADS)

To expand human exploration of the Solar System, the Office of Exploration of the National Aeronautics and Space Administration has awarded 20 contracts for ideas, concepts, devices, systems, and trajectory, operation and implementation plans. Winning proposals came from five industry-related firms, two organizations in the space-support business, and thirteen universities; they were chosen from 115 entries.Geophysical studies to be supported include site characterization of the Oregon moonbase (Oregon L-5 Society, Inc., Oregon City), evolution of design alternatives for exploration of Mars by balloon (Titan Systems, Inc., San Diego, Calif.), design considerations of a lunar production plant (Boston University, Chestnut Hill, Mass.), planetary materials and resource utilization (Michigan Technological University, Houghton), Mars tethered sample return study (University of Colorado, Boulder), Teleprospector, a teleoperated robotic field geologist (University of New Mexico, Albuquerque), and the International Lunar Polar Orbiter (International Space University, Boston, Mass.).

455

[Defloration (a sociomedical study)].  

PubMed

Object of the study were 100 women at fertile age, who informed retrogradely for events connected with disturbance of their virginity. It was established that defloration occurred not at exactly determined moment of the age of young women and girls, but at wider age interval from 16 to 20 years, during noon hours and at night, with equal probability during all seasons, excluding summer, when probability is twice as large, in various places: lodgings, in another's flats, during trips or youth brigades, duration of sexual prey is described, usage of alcohol, ect. An attempt is made to characterize the first partner and stability of the connection between partners, evolution of this connection, which is the background of defloration. The obtained data are compared with data on analogous studies in some other countries. The inferences are proposed as recommendations, which should be taken into consideration by parents, teachers and health services. PMID:2267983

Vasilev, D; Rushkarska, S

1990-01-01

456

Options Study - Phase II  

SciTech Connect

The Options Study has been conducted for the purpose of evaluating the potential of alternative integrated nuclear fuel cycle options to favorably address the issues associated with a continuing or expanding use of nuclear power in the United States. The study produced information that can be used to inform decisions identifying potential directions for research and development on such fuel cycle options. An integrated nuclear fuel cycle option is defined in this study as including all aspects of the entire nuclear fuel cycle, from obtaining natural resources for fuel to the ultimate disposal of used nuclear fuel (UNF) or radioactive wastes. Issues such as nuclear waste management, especially the increasing inventory of used nuclear fuel, the current uncertainty about used fuel disposal, and the risk of nuclear weapons proliferation have contributed to the reluctance to expand the use of nuclear power, even though it is recognized that nuclear power is a safe and reliable method of producing electricity. In this Options Study, current, evolutionary, and revolutionary nuclear energy options were all considered, including the use of uranium and thorium, and both once-through and recycle approaches. Available information has been collected and reviewed in order to evaluate the ability of an option to clearly address the challenges associated with the current implementation and potential expansion of commercial nuclear power in the United States. This Options Study is a comprehensive consideration and review of fuel cycle and technology options, including those for disposal, and is not constrained by any limitations that may be imposed by economics, technical maturity, past policy, or speculated future conditions. This Phase II report is intended to be used in conjunction with the Phase I report, and much information in that report is not repeated here, although some information has been updated to reflect recent developments. The focus in this Options Study was to identify any nuclear fuel cycle technology or option that may result in a significant beneficial impact to the issues as compared to the current U.S. approach of once-through use of nuclear fuel in LWRs or similar reactors followed by direct disposal of UNF. This approach was taken because incremental differences may be difficult to clearly identify and justify due to the large uncertainties that can be associated with the specific causes of the issues. Phase II of this Options Study continued the review of nuclear fuel cycle options that was initiated and documented during Phase I, concentrating on reviewing and summarizing the potential of integrated nuclear fuel cycles. However, based on the reviews of previous studies and available data, it was not always possible to clearly determine sufficiently large differences between the various fuel cycle and technology options for some of the issues or evaluation measures, for example, in cases where only incremental differences with respect to the issues might be achieved regardless of the fuel cycle option or technologies being considered, or where differences were insufficient to clearly rise above the uncertainties.

R. Wigeland; T. Taiwo; M. Todosow; W. Halsey; J. Gehin

2010-09-01

457

EUROv Super Beam Studies  

SciTech Connect

Neutrino Super Beams use conventional techniques to significantly increase the neutrino beam intensity compared to the present neutrino facilities. An essential part of these facilities is an intense proton driver producing a beam power higher than a MW. The protons hit a target able to accept the high proton beam intensity. The produced charged particles are focused by a system of magnetic horns towards the experiment detectors. The main challenge of these projects is to deal with the high beam intensity for many years. New high power neutrino facilities could be build at CERN profiting from an eventual construction of a high power proton driver. The European FP7 Design Study EUROv, among other neutrino beams, studies this Super Beam possibility. This paper will give the latest developments in this direction.

Dracos, Marcos [IPHC, Universite de Strasbourg, CNRS/IN2P3, F-67037 Strasbourg (France)

2011-10-06

458

Fundamental Pyrolysis Studies  

SciTech Connect

Progress on the direct mass spectrometric sampling of pyrolysis products from wood and its constituents is described for the period from June 1982 to February 1983. A brief summary and references to detailed reports, of the qualitative demonstration of our approach to the study of the separated processes of primary and secondary pyrolysis is presented. Improvements and additions to the pyrolysis and data acquisition systems are discussed and typical results shown. Chief of these are a heated-grid pyrolysis system for controlled primary pyrolysis and a sheathed flame arrangement for secondary cracking studies. Qualitative results of the secondary cracking of cellulose, lignin, and wood are shown as are comparisons with the literature for the pyrolysis spectra of cellulose, lignin, and levoglucosan. 'Fingerprints' for a number of materials are shown, with spectra taken under carefully controlled conditions so that sensitivity calibrations for different compounds, now being determined, can be applied.

Milne, T. A.; Evans, R. J.; Soltys, M. N.

1983-03-01

459

A Wetland Field Study  

NSDL National Science Digital Library

The field projects at this site give students an opportunity to investigate a number of wetland characteristics firsthand: surveying wetland vegetation, soils, water quality and wildlife; documenting the wetland from an artist's perspective; investigating land uses along its periphery; and refining a base map upon which all collected information can be recorded. This resource explains how to organize the field study, thereby securing the interest of the students. It is part of a module that aims to help students get to know the complexities of wetlands, discover wildlife, enjoy the experience of being outdoors, and learn how necessary wetlands are to the health of our environment. For educators and their middle school students, it suggests ways to study wetland characteristics, why wetlands are important, and how students and teachers can help protect a local wetland in any part of the country. An associated set of activities is also available.

460

AMTEC material studies  

NASA Astrophysics Data System (ADS)

Texas A&M University, in conjunction with Advanced Modular Power Systems, is performing a series of material studies on key components of an alkali metal thermal to electric conversion (AMTEC) cell for the NASA outer planets power system program. These studies involve SEM, x-ray mapping, EDS, and WDS analysis of AMTEC components from unexposed (as built) samples, from sodium exposure tests, and from operating cells, specifically PX-4C and PX-5B run at the Air Force Research Lab's Phillips Research Site. Findings are still prelimary, but indicate that recrystallization regions seen in the oven samples are an artifact of excess sodium and oxygen levels in those tests, more potassium is present than expected, and that diffusion bonding between the current collector and electrode takes place.

Schuller, Michael; Fiebig, Brad; Hudson, Patricia; Svedberg, Robert

1999-01-01

461

World Biofuels Study  

SciTech Connect

This report forms part of a project entitled 'World Biofuels Study'. The objective is to study world biofuel markets and to examine the possible contribution that biofuel imports could make to help meet the Renewable Fuel Standard (RFS) of the Energy Independence and Security Act of 2007 (EISA). The study was sponsored by the Biomass Program of the Assistant Secretary for Energy Efficiency and Renewable Energy (EERE), U.S. Department of Energy. It is a collaborative effort among the Office of Policy and International Affairs (PI), Department of Energy and Oak Ridge National Laboratory (ORNL), National Renewable Energy Laboratory (NREL) and Brookhaven National Laboratory (BNL). The project consisted of three main components: (1) Assessment of the resource potential for biofuel feedstocks such as sugarcane, grains, soybean, palm oil and lignocellulosic crops and development of supply curves (ORNL). (2) Assessment of the cost and performance of biofuel production technologies (NREL). (3) Scenario-based analysis of world biofuel markets using the ETP global energy model with data developed in the first parts of the study (BNL). This report covers the modeling and analysis part of the project conducted by BNL in cooperation with PI. The Energy Technology Perspectives (ETP) energy system model was used as the analytical tool for this study. ETP is a 15 region global model designed using the MARKAL framework. MARKAL-based models are partial equilibrium models that incorporate a description of the physical energy system and provide a bottom-up approach to study the entire energy system. ETP was updated for this study with biomass resource data and biofuel production technology cost and performance data developed by ORNL and NREL under Tasks 1 and 2 of this project. Many countries around the world are embarking on ambitious biofuel policies through renewable fuel standards and economic incentives. As a result, the global biofuel demand is expected to grow very rapidly over the next two decades, provided policymakers stay the course with their policy goals. This project relied on a scenario-based analysis to study global biofuel markets. Scenarios were designed to evaluate the impact of different policy proposals and market conditions. World biofuel supply for selected scenarios is shown in Figure 1. The reference case total biofuel production increases from 12 billion gallons of ethanol equivalent in 2005 to 54 billion gallons in 2020 and 83 billion gallons in 2030. The scenarios analyzed show volumes ranging from 46 to 64 billion gallons in 2020, and from about 72 to about 100 billion gallons in 2030. The highest production worldwide occurs in the scenario with high feedstock availability combined with high oil prices and more rapid improvements in cellulosic biofuel conversion technologies. The lowest global production is found in the scenario with low feedstock availability, low oil prices and slower technology progress.

Alfstad,T.

2008-10-01

462

Institute of Development Studies  

NSDL National Science Digital Library

Located in Sussex, England, the Institute of Development Studies (IDS) is an international authority on development. IDS serves as a center for research and education on development and offers conferences and workshops, as well as a host of online information about research and publications. Full-text working and discussion papers are available online, as are several special research reports and descriptions of projects on such subjects as Globalization, Governance and Civil Society, and Environment.

463

The JACS Study I  

Microsoft Academic Search

In order to learn more about chemically dependent Jew -ish people, and to help dispel the misinformation about them, the au -thors surveyed individuals who were part of the JACS database.Data from 379 questionnaires were analyzed and compared with the findings of two general population surveys of Jews and a previous study of Jewish alcoholics.Seventy-one percent of respondents reported dependence

Susan Lind Vex; Sheila B. Blume

2001-01-01

464

Studies in quantum geometry  

NASA Astrophysics Data System (ADS)

The geometric defects associated with open strings have become a mainstay in the arsenal of the string theorist. These objects are intimately tied to the properties of spacetime. D-branes have been well studied in the nineties and orientifolds are only now been thoroughly investigated. This thesis is built on two different studies. The first, done with Koenraad Schalm and Chuck Doran attempts to analyze the possible Orientifolds and their moduli, starting from Gepner models of the spacetime. The main focus was on elliptical compactifications, as this could be used as building block for more complex geometries. It is noteworthy that the orientifolds place constraints on the possible spacetime geometries, whilst also being characterized by the geometrical nature of the involutions defining them. The second study of this thesis, which was done with Frederik Denef, is on the low energy manifestations of D-branes as supergravity attractor solutions. Four dimensional N = 2 supergravity has regular, stationary, asymptotically flat BPS solutions with intrinsic angular momentum, describing bound states of separate extremal black holes with mutually nonlocal charges. Though the existence and some properties of these solutions were established some time ago, fully explicit analytic solutions were lacking thus far. In this study this gap is filled. We found that in general explicit solutions can be constructed whenever an explicit formula is known in the theory at hand for the Bekenstein-Hawking entropy of a single black hole as a function of its charges, and illustrated this with some simple examples. We also found an example of moduli-dependent black hole entropy.

Bates, Brandon D.

465

Mars Rover RTG Study  

SciTech Connect

This report summarizes the results of a Radioisotope Thermoelectric Generator (RTG) design study conducted by Fairchild Space Company at the direction of the U.S. Department of Energy's Office of SpecialApplications, in suppport of the Mars Rover and Sample Return mission under investigation at NASA's Jet Propulsion Laboratory. The report is a rearranged, updated, and significantly expanded amalgam of three interrelated papers presented at the 24th Intersocity Energy Conversion Engineering Conference (IECEC) at Arlington, Virginia, on August 10, 1989.

Schock, Alfred

1989-08-25

466

Mössbauer studies of malaria  

NASA Astrophysics Data System (ADS)

Mössbauer studies of rat and human erythrocytes infected by malarial parasites have been carried out. Different parameters of the pigment iron were obtained in human and rat infected red blood cells. No difference was found between the parameters obtained in rat erythrocytes infected by drug sensitive and drug resistant strains of p. berghei, both before and after the treatment with chloroquine. The pigment was shown to contain a trivalent, high spin iron compound, which is different from hematin.

Bauminger, E. R.; Ginsburg, H.; Ofer, S.; Yayon, A.

1983-12-01

467

Right Brain Study  

Microsoft Academic Search

The purpose of this study is to show that instructional methods designed for right-brained students will make a significant difference in the reading achievement scores of the students when compared with the scores of right-brained sixth grade students not receiving these instructional methods.The subjects were sixth grade students who use the right hemisphere of the brain to a greater degree

Velda L Griffin

1985-01-01

468

INFRARED STUDIES OF PULSARS  

SciTech Connect

The light curve of the Crab Nebula Pulsar has been studied in the near infrared (.9 {micro}m - 2.4 {micro}m) and found to be similar to the optical light curve except for a shoulder after each main peak. A search for infrared pulsations from other promising candidates was negative, with typical upper limits 3 - 5 magnitudes fainter than the Crab.

Pennypacker, Carlton R.

1980-10-01

469

Stratospheric Aerosol Studies  

Microsoft Academic Search

The stratospheric aerosol layer previously identified by balloon measurements has been studied extensively by means of recovered rod impactor samples obtained during aircraft flights at the 20-km level from 63øS to 72øN during March-November 1960. From a variety of physical and chemical measurements, which are presented in detail, the conclusion is drawn that this layer is stable, constant in time

Christian E. Junge; James E. Manson

1961-01-01

470

Winking Skull Study Aid  

NSDL National Science Digital Library

WinkingSkull.com is a free, interactive resource for medical students and people interested in science. This website allows users to turn labels on or off while studying. A testing feature allows users to drag and drop labels onto the anatomical illustrations while being timed. Users may view test results instantly to measure their proficiency of the material and compare scores with other users.

Thieme Publishers (Thieme Publishers)

2008-01-01

471

The zurich study  

Microsoft Academic Search

A representative sample of 456 persons from the normal population aged 22 and 23 years was used to study the overlap of depression with anxiety disorders. The 1-year prevalence rate for major depression (DSM-III), minor depression, and anxiety disorder together was 16.4%. The observed cases of major depression cooccurred in 36% with anxiety disorder, the cases with minor depression in

J. Angst; A. Dobler-Mikola

1985-01-01

472

The Zurich study  

Microsoft Academic Search

Summary The problems in association with agoraphobia and social phobia were examined in an 11-year prospective longitudinal study of a Swiss cohort of young adults. The weighted prevalence rates according to DSM-III were 2.9% for agoraphobia and 3.8% for social phobia. Although the problem of agoraphobia was greater in females, an equal sex ratio was observed for social phobia. There

Martina Degonda; Jules Angst

1993-01-01

473

Journal of Millennial Studies  

NSDL National Science Digital Library

This online journal is produced by the Center for Millennial Studies, an organization devoted to archiving apocalyptic literature and analyzing millenarianism. The inaugural issue contains five articles and a book review in .pdf format. These include: "Religion INK.: Tabloid Crucifiction (Whose Apocalypse? When?)," "Jewish Shock-Troops of the Apocalypse: Antichrist and the End, 1200-1600," and "The Mongols and non-believing apocalyptic friends around the year 1260."

1998-01-01

474

Agricultural Health Study  

Cancer.gov

This study explores potential causes of cancer and other diseases among farmers and their families and among commercial pesticide applicators. Current medical research suggests that while agricultural workers are generally healthier than the general U.S. population, they may have higher rates of some cancers, including leukemia, myeloma, non-Hodgkin's lymphoma, and cancers of the lip, stomach, skin, brain, and prostate. Other conditions, like asthma, neurologic disease, and adverse reproductive outcomes may also be related to agricultural exposures.

475

Electrochemical studies of SIMFUELs  

NASA Astrophysics Data System (ADS)

The properties of a standard UO2 fuel and three SIMFUEL materials (unirradiated analogues of used nuclear fuels) have been characterized electrochemically and under natural corrosion conditions. The general oxidation and reduction behavior was determined voltammetrically. The effect of substituents on the surface reactivity was determined by studying the electroreduction of O2. Under natural corrosion conditions, SIMFUEL s oxidize more rapidly than does UO2, but then appear to dissolve at a similar rate.

Shoesmith, D. W.; Hocking, W. H.; Sunder, S.; Betteridge, J. S.; Miller, N. H.

1994-10-01

476

Electron microscope studies  

SciTech Connect

This year our laboratory has continued to make progress in the design of electron-optical systems, in the study of structure-function relationships of large multi-subunit proteins, in the development of new image processing software and in achieving a workable sub-angstrom STEM. We present an algebraic approach to the symmetrical Einzel (unipotential) lens wherein we simplify the analysis by specifying a field shape that meets some preferred set of boundary or other conditions and then calculate the fields. In a second study we generalize this approach to study of three element electrostatic lenses of which the symmetrical Einzel lens is a particular form. The purpose is to develop a method for assisting in the design of a lens for a particular purpose. In our biological work we study a stable and functional dodecameric complex of globin chains from the hemoglobin of Lumbricus terrestris. This is a complex lacking the linker'' subunit first imaged in this lab and required for maintenance of the native structure. In addition, we do a complete work-up on the hemoglobin of the marine polychaete Eudistylia vancouverii demonstrating the presence of a hierarchy of globin complexes. We demonstrate stable field-emission in the sub-angstrom STEM and the preliminary alignment of the beam. We continue our exploration of a algorithms for alignment of sequences of protein and DNA. Our computer facilities now include four second generation RISC workstations and we continue to take increasing advantage of the floating-point and graphical performance of these devices.

Crewe, A.V.; Kapp, O.H.

1991-06-01

477

QUADRENNIAL MCNP TIMING STUDY  

SciTech Connect

The Los Alamos National Laboratory Monte Carlo N-Particle radiation transport code, MCNP, is widely used around the world for many radiation protection and shielding applications. As a well-known standard it is also an excellent vehicle for assessing the relative performance of scientific computing platforms. Every three-to-four years a new version of MCNP is released internationally by the Radiation Safety Information Computational Center (RSICC) in Oak Ridge, Tennessee. For each of the past few releases, we have also done a timing study to assess the progress of scientific computing platforms and software. These quadrennial timing studies are valuable to the radiation protection and shielding community because (a) they are performed by a recognized scientific team, not a computer vendor, (b) they use an internationally recognized code for radiation protection and shielding calculations, (c) they are eminently reproducible since the code and the test problems are internationally distributed. Further, if one has a computer platform, operating system, or compiler not presented in our results, its performance is directly comparable to the ones we report because it can use the same code, data, and test problems as we used. Our results, using a single processor per platform, indicate that hardware advances during the past three years have improved performance by less than a factor of two and software improvements have had a marginal effect on performance. The most significant impacts on performance have resulted from developments in multiprocessing and multitasking. The other most significant advance in the last three years has been the accelerated improvements in personal computers. In the last timing study, the tested personal computer was approximately a factor of four slower that the fastest machine tested, a DEC Alphastation 500. In the present study, the fastest PC tested was less than a factor of two slower than the fastest platform, which is a Compaq (previously DEC) Alpha XP1000.

E. C. SELCOW; B. D. LANSRUD

2000-09-01

478

Microengineered cathode interface studies  

SciTech Connect

The overpotential at the cathode/electrolyte interface has been recognized as an important limitation on the performance of solid oxide fuel cells (SOFCs). This project is an effort to gain a scientific understanding of which interface features and conditions contribute to cathode polarization in SOFCs. The paper discusses three possible rate-limiting factors in the cathode reaction. The paper studies the electronic conductivity in the electrolyte, the ionic conductivity in the cathode, cathode geometry near the interface, and cathode surface area.

Kueper, T.; Doshi, R.; Krumpelt, M. [Argonne National Lab., IL (United States). Electrochemical Technology Program

1996-10-01

479

Study of Organic Scintillators  

Microsoft Academic Search

The scintillation counting behavior of a group of fifty-five pure crystalline organic compounds has been extensively studied. The data obtained have been analyzed with the goal of developing a better understanding of the scintillation process and of scintillator behavior.The materials were carefully purified, and massive crystals were grown. Relative scintillation average-pulse-height efficiencies at 30°C and —70°C for cobalt-60 gamma-ray excitation,

Raymond C. Sangster; John W. Irvine

1956-01-01

480

Women's Health Study (WHS)  

Cancer.gov

The Women's Health Study (WHS) is a randomized, double-blind, placebo-controlled trial using a 2x2 factorial design, and conducted among 39,876 female health professionals in the United States. The WHS is sponsored by both the National Cancer Institute (NCI) and the National Heart, Lung, and Blood Institute (NHLBI). Participants were randomly assigned to either Vitamin E (600 IU every other day) or placebo; and to aspirin (100 mg every other day) or placebo.

481

Through bulkhead initiator studies  

Microsoft Academic Search

This report describes recent work done to demonstrate feasibility of a fail-safe Through Bulkhead Initiator with minimum dimensions and suitable for use in cyclical thermal environments. Much of the ground work for a fail-safe TBI was previously done by A.C. Schwartz. This study is an expansion of Schwartz`s work to evaluate devices with bulkheads of 304 stainless steel and Inconel

David R. Begeal

1997-01-01

482

Prospective venox feasibility study.  

PubMed

Venox is a propriety Venous Oximetry system, capable of measuring peripheral venous oximetry. In this ongoing study, Venox is being compared against mixed central venous oximetry during human cardiac surgery, with Fibre optic reflectance spectrophotometry being used as the gold standard, placed in the pulmonary artery. A background review of the Pulse oximetry, current venous oximetry techniques and the potential advantage of the VENOX system are discussed. Lessons learnt, Preliminary results, and future plans are included in discussion. PMID:17282608

Crabtree, Vincent; Echiadis, Angelos; Smith, Peter; Boehm, Maria; Oc, Mehmet; Bence, Johan; Machin, David; Swanavelder, Justiann; Alexiou, Christos; Doukas, George; Pidgeon, Willis; Hadjinikolaou, Leon; Spyt, Tomasz

2005-01-01

483

Software breadboard study  

NASA Astrophysics Data System (ADS)

The overall goal of this study was to develop new concepts and technology for the Comet Rendezvous Asteroid Flyby (CRAF), Cassini, and other future deep space missions which maximally conform to the Functional Specification for the NASA X-Band Transponder (NXT), FM513778 (preliminary, revised July 26, 1988). The study is composed of two tasks. The first task was to investigate a new digital signal processing technique which involves the processing of 1-bit samples and has the potential for significant size, mass, power, and electrical performance improvements over conventional analog approaches. The entire X-band receiver tracking loop was simulated on a digital computer using a high-level programming language. Simulations on this 'software breadboard' showed the technique to be well-behaved and a good approximation to its analog predecessor from threshold to strong signal levels in terms of tracking-loop performance, command signal-to-noise ratio and ranging signal-to-noise ratio. The successful completion of this task paves the way for building a hardware breadboard, the recommended next step in confirming this approach is ready for incorporation into flight hardware. The second task in this study was to investigate another technique which provides considerable simplification in the synthesis of the receiver first LO over conventional phase-locked multiplier schemes and in this approach, provides down-conversion for an S-band emergency receive mode without the need of an additional LO. The objective of this study was to develop methodology and models to predict the conversion loss, input RF bandwidth, and output RF bandwidth of a series GaAs FET sampling mixer and to breadboard and test a circuit design suitable for the X and S-band down-conversion applications.

Nuckolls, C.; Frank, Mark

1990-01-01

484

Laser Initiated Actuator study  

SciTech Connect

The program task was to design and study a laser initiated actuator. The design of the actuator is described, it being comprised of the fiber and body subassemblies. The energy source for all experiments was a Spectra Diode 2200-H2 laser diode. The diode is directly coupled to a 100 micron core, 0.3 numerical aperture fiber optic terminated with an SMA connector. The successful testing results are described and recommendations are made.

Watson, B.

1991-06-27

485

Lumbar degenerative classification study.  

PubMed

The purpose of this study was to develop and validate a classification of indications for fusion in lumbar degenerative disease. Nineteen spine surgeons reviewed a series of 32 case histories and selected the indication for fusion based on an outlined classification system. To determine the degree of interrater variability, K coefficients were calculated (K for all 32 cases, 0.63). Results from this study show the significant difficulty in classifying the indication for fusion in lumbar degenerative disease. The level of the 19 surgeons' agreement regarding surgical indication was only moderate, despite a study design that eliminated controversial issues of patient and procedure selection. To a significant extent, the difficulty in classifying indication for fusion underlines the importance of the process. If we cannot agree on why a specific patient is selected for fusion, it is then impossible to accurately compare outcomes for a given disease process or surgical technique. For this reason, an ongoing effort to refine nomenclature and classification is necessary. PMID:16689515

Glassman, Steven D; Carreon, Leah Y; Dimar, John R; Campbell, Mitchell J; Johnson, John R; Puno, Rolando M

2006-04-01

486

?-Oligofurans: A Computational Study.  

PubMed

Recently, ?-oligofurans have emerged as interesting and promising organic electronic materials that have certain advantages over ?-oligothiophenes. In this work, ?-oligofurans were studied computationally, and their properties were compared systematically with those of the corresponding oligothiophenes. Although the two materials share similar electronic structures, overall, this study revealed important differences between ?-oligofurans and ?-oligothiophenes. Twisting studies on oligofurans revealed them to be significantly more rigid than oligothiophenes in the ground state and first excited state. Neutral ?-oligofurans have more quinoid character, higher frontier orbital energies, and higher HOMO-LUMO gaps than their ?-oligothiophene counterparts. The theoretical results suggest that oligofurans (and subsequently polyfuran) have lower ionization potentials than the corresponding oligothiophenes (and polythiophene), which in turn predicts that oligofurans can be lightly doped more easily than oligothiophenes. Oligofuran dications (8?F(2+) -14?F(2+) ) of medium-sized and longer chain lengths show a polaron-pair character, and the polycations of ?-oligofurans cannot accommodate high positive charges as easily as their thiophene analogues. PMID:23940018

Sharma, Sagar; Bendikov, Michael

2013-08-12

487

ADVANCED CUTTINGS TRANSPORT STUDY  

SciTech Connect

This is the third quarterly progress report for Year 3 of the ACTS Project. It includes a review of progress made in: (1) Flow Loop construction and development and (2) research tasks during the period of time between Jan. 1, 2002 and Mar. 31, 2002. This report presents a review of progress on the following specific tasks: (a) Design and development of an Advanced Cuttings Transport Facility (Task 3: Addition of a Cuttings Injection/Separation System), (b) Research project (Task 6): ''Study of Cuttings Transport with Foam Under LPAT Conditions (Joint Project with TUDRP)'', (c) Research project (Task 9b): ''Study of Foam Flow Behavior Under EPET Conditions'', (d) Research project (Task 10): ''Study of Cuttings Transport with Aerated Mud Under Elevated Pressure and Temperature Conditions'', (e) Research on three instrumentation tasks to measure: Cuttings concentration and distribution in a flowing slurry (Task 11), Foam texture while transporting cuttings. (Task 12), and Viscosity of Foam under EPET (Task 9b); (f) Development of a Safety program for the ACTS Flow Loop, progress on a comprehensive safety review of all flow-loop components and operational procedures. (Task 1S); and (g) Activities towards technology transfer and developing contacts with Petroleum and service company members, and increasing the number of JIP members.

Troy Reed; Stefan Miska; Nicholas Takach; Kaveh Ashenayi; Mark Pickell; Len Volk; Mike Volk; Evren Ozbayoglu; Lei Zhou

2002-04-30

488

The Walkerton Health Study.  

PubMed

The contamination of the Walkerton, Ontario, municipal water with E. coli O157:H7 and Campylobacter in May 2000 resulted in at least 2,300 cases of gastrointestinal illness. There were 28 confirmed cases of hemolytic uremic syndrome, the most severe kidney complication. The provincial Ministry of Health and Long-Term Care determined that a study needed to be conducted on the long-term health effects associated with drinking the contaminated water. The Walkerton Health Study, a seven-year project, was established as a screening and treatment clinic to identify and treat those people experiencing illness and to study long-term health effects. This article describes the challenges, infrastructure support, staffing, and recruitment and retention efforts required to screen over 4,000 people in a yearly clinic visit. Clinical and laboratory algorithms are used to identify participants requiring specialist assessment. Design of the computer-based survey includes advanced data entry and display control, essential to ensuring accurate data for analysis. Findings from Years 1, 2 and 3 are briefly discussed. PMID:16035513

Richards, Arlene

2005-05-01

489

Energetic component treatability study  

SciTech Connect

The effectiveness of three environmentally sound processes for small energetic component disposal was examined experimentally in this study. The three destruction methods, batch reactor supercritical water oxidation, sodium hydroxide base hydrolysis and calcium carbonate cookoff were selected based on their potential for producing a clean solid residue and minimum release of toxic gases after component detonation. The explosive hazard was destroyed by all three processes. Batch supercritical water oxidation destroyed both the energetics and organics. Further development is desired to optimize process parameters. Sodium hydroxide base hydrolysis and calcium carbonate cookoff results indicated the potential for scrubbing gaseous detonation products. Further study and testing are needed to quantify the effectiveness of these later two processes for full-scale munition destruction. The preliminary experiments completed in this study have demonstrated the promise of these three processes as environmentally sound technologies for energetic component destruction. Continuation of these experimental programs is strongly recommended to optimize batch supercritical water oxidation processing, and to fully develop the sodium hydroxide base hydrolysis and calcium carbonate cookoff technologies.

Gildea, P.D.; Brandon, S.L.; Brown, B.G. [and others

1997-11-01

490

Studying for multiprimary LCD  

NASA Astrophysics Data System (ADS)

The recent color display market is being focused on displays with larger panel size and larger color gamut. More specifically, for widening the color gamut, multi-primary display (MPD), which is a display having more than the conventional three-channels, has been an important issue. However, developing MPD faces many difficulties such as sustaining display luminance against 3-color displays, embodying a simple H/W structure, and assigning new color signals based on input RGB signals. The purpose of this study is to propose a method to display color on a new pixel structure for flat-panel displays with six primary colors intended to expand the color gamut, and to discuss a color decomposition algorithm for this new structure to assign signals to 6-channels from an input RGB signal. Special interests of this study are made on minimizing the deterioration of color image quality compared with RGB-based display and maximizing the usage of the widened color gamut. The result of this study was implemented on a prototype 6-color LCD and verified generation of the color signals for 6 primary colors without luminance degradation. The device is capable of reproducing colors like emerald cyan, which cannot be displayed on a conventional RGB display. In addition, hardware implementation on FPGA verified commercial viability of the algorithm.

Choe, Wonhee; Lee, Seong-Deok; Kim, Chang-Yong

2004-12-01

491

Robotics vehicle mobility study  

NASA Astrophysics Data System (ADS)

A nine-month study was conducted under the direction of Tank-Automotive Research, Development and Engineering Center (TARDEC) in Warren, MI. to determine the best platform design for inherent all-terrain mobility of an unmanned robotic vehicle in the 15000-2500 lb. range. Reference platforms were the DEMO III 4x4 and the Utah State University 6x6 with omni-directional wheels. The study systematically developed desired top- down design-driving capabilities, operational needs, and mobility concepts supported by extensive analysis using the NATO Reference Mobility Model and literature searches. Maximizing mobility over all terrain and resisting immobilization were emphasized in order to minimize sensor computational burdens while maximizing the probability of timely mission accomplishment. Several wheeled, tracked and hybrid platform concepts were evaluated. Significant improvements in cross- country mobility, obstacle negotiation and self-extraction capability were achieved with hybrid solutions. Final concept development focused on an 8x8 swiveling wheeled platform with band track overlays. Conclusions of the study were: a technology demonstrator platform should be built for mobility validation and NRMM II refinemment; a robotic- vehicle-specific NRMM II mobility scenario should be developed; and sensor solutions for unmanned mobility platforms should be revisited.

Ansorge, Kurt H.; Pond, James E.

2000-07-01

492

AMT: preclinical pharmacology studies.  

PubMed

Auron-Misheil-Therapy (AMT) consisting of aqueous camomile extract supplemented with calcium, vitamins, the antihistamine chlorpheniramine and human insulin is under development as anti-cancer treatment. AMT was preclinically investigated in tumour cell lines and tumour xenografts to guide clinical phase I/II studies. AMT was tested against 56 human tumour cell lines, in a clonogenic assay in 98 patient-derived xenografts and in in vivo studies. AMT showed in vitro cytotoxic activity with highest susceptibility in cervical cancer, glioblastoma and colon cancers. In the clonogenic assay, anti- cancer activity of AMT was most active in cervical and uterine tumours, in colon cancer, glioblastoma, leukaemia, melanoma and pancreatic cancer. In vivo, AMT showed slight activity in tumour xenograft models of colon and mammary cancer. It also showed immune stimulatory effects by induction of IL-6- and TNF-alpha secretion in human PBMCs. The immune stimulatory potential of AMT, together with slight anti-tumour efficacy observed in the present study, indicates a role of AMT in tumour therapy. PMID:19360346

Niazi, Faiz; Drevs, Joachim; Diergarten, Klaus; Dorn, Annette; Maier, Armin; Fiebig, Heinz Herbert; Bruyns, Eddy; Scheele, Jürgen

2009-05-01

493

The safeguards options study  

SciTech Connect

The Safeguards Options Study was initiated to aid the International Safeguards Division (ISD) of the DOE Office of Arms Control and Nonproliferation in developing its programs in enhanced international safeguards. The goal was to provide a technical basis for the ISD program in this area. The Safeguards Options Study has been a cooperative effort among ten organizations. These are Argonne National Laboratory, Brookhaven National Laboratory, Idaho National Engineering Laboratory, Lawrence Livermore National Laboratory, Los Alamos National Laboratory, Mound Laboratory, Oak Ridge National Laboratory, Pacific Northwest Laboratories, Sandia National Laboratories, and Special Technologies Laboratory. Much of the Motivation for the Safeguards Options Study is the recognition after the Iraq experience that there are deficiencies in the present approach to international safeguards. While under International Atomic Energy Agency (IAEA) safeguards at their declared facilities, Iraq was able to develop a significant weapons program without being noticed. This is because negotiated safeguards only applied at declared sites. Even so, their nuclear weapons program clearly conflicted with Iraq`s obligations under the Nuclear Nonproliferation Treaty (NPT) as a nonnuclear weapon state.

Hakkila, E.A.; Mullen, M.F.; Olinger, C.T.; Stanbro, W.D. [Los Alamos National Lab., NM (United States); Olsen, A.P.; Roche, C.T.; Rudolph, R.R. [Argonne National Lab., IL (United States); Bieber, A.M.; Lemley, J. [Brookhaven National Lab., Upton, NY (United States); Filby, E. [Idaho National Engineering Lab., Idaho Falls, ID (United States)] [and others

1995-04-01

494

Operations dashboard: comparative study  

NASA Astrophysics Data System (ADS)

In this present days and age, there are increasing needs for companies to monitor application and infrastructure health. Apart from having proactive measures to secure their application and infrastructure, many see monitoring dashboards as crucial investment in disaster preparedness. As companies struggle to find the best solution to cater for their needs and interest for monitoring their application and infrastructure's health, this paper summarizes the studies made on several known off-the-shelf operations dashboard and in-house developed dashboard. A few criteria of good dashboard are collected from previous studies carried out by several researchers and rank them according to importance and business needs. The finalized criteria that will be discussed in later sections are data visualization, performance indicator, dashboard personalization, audit capability and alert/ notification. Comparative studies between several popular dashboards were then carried out to determine whether they met these criteria that we derived from the first exercise. The findings hopefully can be used to educate and provide an overview of selecting the best IT application and infrastructure operations dashboard that suit business needs, thus become the main contribution of this paper.

Ramly, Noor Nashriq; Ismail, Ahmad Zuhairi; Aziz, Mohd Haris; Ahmad, Nurul Haszeli

2011-10-01

495

Epidemiological studies on syncope.  

PubMed

The epidemiology and prognosis of ''fainting'' or syncope has puzzled physicians over the years. Is fainting dangerous? This is a question often asked by the patient- and the answer is ''it depends on a lot of things''. The diverse pathophysiology of syncope and the underlying comorbidites of the patients play an essential role. In epidemiology these factors have major impact on the outcome of the patients. Until recently, even the definition of syncope differed from one study to another which has made literature reviews difficult. Traditionally the data on epidemiology of syncope has been taken from smaller studies from different clinical settings with wide differences in patient morbidity. Through the extensive Danish registries we examined the characteristics and prognosis of the patients hospitalized due to syncope in a nationwide study. The aims of the present thesis were to investigate: 1) the use, validity and accuracy of the ICD-10 diagnosis of syncope R55.9 in the National Patient Registry for the use of this diagnosis in the epidemiology of syncope, 2) diagnostics used and etiology of a random selection of patients who had a discharge diagnosis of R55.9, 3) the incidence, prevalence and cardiovascular factors associated with the risk of syncope, 4) the prognosis in healthy individuals discharged after syncope, and 5) the prognosis of patients after syncope and evaluation of the CHADS2 score as a tool for short- and long-term risk prediction. The first studies of the present thesis demonstrated that the ICD-10 discharge diagnosis could reliably identify a cohort of patients admitted for syncope and that the discharge code carried a high number of unexplained cases despite use of numerous tests. The last studies showed that syncope is a common cause for hospital contact in Denmark and that the risk of syncope is tightly associated with cardiovascular co-morbidities and use of pharmacotherapy. Furthermore in patients with no co-morbidities (or healthy individuals), syncope is a significant and independent prognostic factor of adverse cardiovascular outcome and death compared to the background population. Lastly, evaluation of the CHADS2 score, as a tool for risk stratification, showed that it provided additional prognostic information on short- and long-term cardiovascular mortality in syncope patients compared to controls. PMID:24001470

Ruwald, Martin Huth

2013-09-01

496

Platelet satellitism: experimental studies.  

PubMed

Platelet satellitism (PS), the in vitro phenomenon of platelets rosetting about nonlymphocytic leukocytes, is an uncommon and poorly understood finding reported in the ethylenediaminetetra-acetic acid (EDTA)-anticoagulated blood of patients with a wide variety of clinical conditions. This report presents experimental studies investigating the nature of this phenomenon by utilizing the blood of patients with platelet satellitism. Wet preparation studies and electron microscopy (transmission and scanning) demonstrated the morphologic sequences involved in the phenomenon, including eventual phagocytosis of platelets by neutrophils. The results of varying conditions such as time, temperature, and anticoagulant are described. All of five patients tested were found to have cryofibrinogenemia. Certain blood components from all of three patients tested were capable of inducing PS in normal whole blood, whereas components from normal subjects usually were not. In one patient (A), the PS-inducing capability appeared to be present in both plasma and platelets. In another patient (B) the PS-inducing capability was present in platelets (in both 1966 and 1975) and also in the cryosupernate of serum and plasma; among various antisera, antifibrinogen had the greatest ability to reduce the degree of PS in patient blood; addition of moderate amounts of CaCl2 and/or MgCl2 did not diminish the phenomenon; and two sisters and two daughters demonstrated no PS. In a third patient (C) the PS-inducing capability appeared to be largely concentrated in the cryoprecipitable fraction of plasma. These studies suggest that there are different factors in the patients' blood resulting in PS. Further studies showed PS could be induced in normal blood by adding certain nonprimate antihuman antisera (anti-IgM, antialbumin or antifibrinogen) and also by adding some preparations of normal washed platelets to the same individuals's normal whole blood. This indicates that the phenomenon of PS can be produced by factors other than those specifically present in patients with PS. Antigen-antibody complexes, either formed in vivo (mixed cryoglobulinemia) or in vitro, did not result in PS when mixed with normal blood. These and other studies suggest that PS can result from the presence of several different factors, usually proteins (in conjunction with EDTA), which probably attach to the surface of platelets apparently resulting in some alteration (such as change in surface charge) causing the platelets to be attracted to and phagocytosed by neutrophils. PMID:6767139

McGregor, D H; Davis, J W; Liu, P I; Gates, E; Poindexter, A R

1980-03-01

497

Carcinogenicity studies on ebrotidine.  

PubMed

The results from two carcinogenicity studies on ebrotidine (N-[2-(E)-[[2-[[[2-[(diaminomethylene)amino]-4-thiazolyl] methyl]thio]ethyl]amino]methylene]-4-bromo-benzenesulfonamide, CAS 100981-43-9, FI-3542) conducted in mice and rats are reported. Oral doses of 50, 200 and 500 mg/kg were administered to mice for 18 months and 50, 200 (150), 300 and 500 mg/kg were administered to rats for 24 months. The study design was prepared according to EEC guidelines, and the recommendations by the International Agency for Research on Cancer were used for the statistical analysis of data. Weekly palpations were made along the course of studies and general parameters were monitored. The only effects attributed to ebrotidine administration were a slight decrease in the survival rate of female mice given the 500 mg/kg dose and a lower weight gain in rats of both sexes. The histopathological data revealed that lipoid pneumonia and kidney calculi are more frequent in rats treated with doses of 500 and 300 mg/kg. No increment in the spontaneous occurrence of tumours or significant presence of tumours in treated animals differing from that in control animals was observed, and a decrease in the time required for their onset that could be related to ebrotidine was not observed either. There were no differences in hyperplastic and/or dysplastic changes between treated and control animals. Therefore, it is deduced that ebrotidine does not induce neoplastic or preneoplastic effects in rats or mice even at doses of 500 mg/kg, at which some general toxicity effects are seen. PMID:9205755

Romero, A; Rives, A; Grau, M T; Villamayor, F; Sacristán, A; Ortiz, J A

1997-04-01

498

Exploratory studies, 1991  

SciTech Connect

The Exploratory Studies Group is dedicated to advanced investigation of accelerators and radiation, primarily in the area of charged-particle beams and photon beams. Its primary mission is to explore the next steps in the development of particle accelerators and storage rings, which are important both for high-energy physics and for the wide range of disciplines now turning to synchrotron-radiation sources and free-electron lasers. Our research is therefore deeply committed to LBL's institutional goal of becoming a center for the generation and use of coherent and incoherent electromagnetic radiation of exceptional brightness, as well as for generic research on the future development of accelerators. A significant fraction of our effort is dedicated to general accelerator-physics research for facilities on the immediate horizon, but a vital part of our activities comprises research into exotic possibilities for charged-particle production, accumulation, acceleration, and storage. During this report period, we were proncipally involved in four general areas of study: Accelerator-physics research for the Advanced Light Source, the 1-2 GeV synchrotron radiation source now under construction at LBL. In collaboration with the Stanford Linear Accelerator Center, both the conceptual and the detailed design of PEP-II, an energy-asymmetric electron-positron collider, based on the PEP ring at SLAC and designed to serve as a B-meson factory. Studies of ultraviolet and infrared free-electron lasers based on linear accelerators and storage rings, in particular the conceptual design of an infrared free-electron laser for the proposed Chemical Dynamics Research Laboratory at LBL. Generic high-energy accelerator-physics and photon-beam research directed far into the future to envision facilities that would employ new techniques of particle-beam acceleration and storage and photon-beam generation.

Not Available

1992-03-01

499

Exploratory studies, 1991  

SciTech Connect

The Exploratory Studies Group is dedicated to advanced investigation of accelerators and radiation, primarily in the area of charged-particle beams and photon beams. Its primary mission is to explore the next steps in the development of particle accelerators and storage rings, which are important both for high-energy physics and for the wide range of disciplines now turning to synchrotron-radiation sources and free-electron lasers. Our research is therefore deeply committed to LBL`s institutional goal of becoming a center for the generation and use of coherent and incoherent electromagnetic radiation of exceptional brightness, as well as for generic research on the future development of accelerators. A significant fraction of our effort is dedicated to general accelerator-physics research for facilities on the immediate horizon, but a vital part of our activities comprises research into exotic possibilities for charged-particle production, accumulation, acceleration, and storage. During this report period, we were proncipally involved in four general areas of study: Accelerator-physics research for the Advanced Light Source, the 1-2 GeV synchrotron radiation source now under construction at LBL. In collaboration with the Stanford Linear Accelerator Center, both the conceptual and the detailed design of PEP-II, an energy-asymmetric electron-positron collider, based on the PEP ring at SLAC and designed to serve as a B-meson factory. Studies of ultraviolet and infrared free-electron lasers based on linear accelerators and storage rings, in particular the conceptual design of an infrared free-electron laser for the proposed Chemical Dynamics Research Laboratory at LBL. Generic high-energy accelerator-physics and photon-beam research directed far into the future to envision facilities that would employ new techniques of particle-beam acceleration and storage and photon-beam generation.

Not Available

1992-03-01

500

Numerical studies in geophysics  

NASA Astrophysics Data System (ADS)

This thesis focuses on the use of modern numerical techniques in the geo- and environmental sciences. Four topics are discussed in this thesis: finite Prandtl number convection, wavelet analysis, inverse methods and data assimilation, and nuclear waste tank mixing. The finite Prandtl number convection studies examine how convection behavior changes as Prandtl numbers are increased to as high as 2 x 104, on the order of Prandtl numbers expected in very hot magmas or mushy ice diapirs. I found that there are significant differences in the convection style between finite Prandtl number convection and the infinite Prandtl number approximation even for Prandtl numbers on the order of 104. This indicates that the infinite Prandtl convection approximation might not accurately model behavior in fluids with large, but finite Prandtl numbers. The section on inverse methods and data assimilation used the technique of four dimensional variational data assimilation (4D-VAR) developed by meteorologists to integrate observations into forecasts. It was useful in studying the predictability and dependence on initial conditions of finite Prandtl simulations. This technique promises to be useful in a wide range of geological and geophysical fields, including mantle convection, hydrogeology, and sedimentology. Wavelet analysis was used to help image and scrutinize at small-scales both temperature and vorticity fields from convection simulations and the geoid. It was found to be extremely helpful in both cases. It allowed us to separate the information in the data into various spatial scales without losing the locations of the signals in space. This proved to be essential in understanding the processes producing the total signal in the datasets. The nuclear waste study showed that techniques developed in geology and geophysics can be used to solve scientific problems in other fields. I applied state-of-the-art techniques currently employed in geochemistry, sedimentology, and mantle mixing to simulate dynamical processes occurring in the course of mixing nuclear waste tanks.

Hier Majumder, Catherine Anne

2003-10-01