bluuebunny/crossref_metadata_2025 huggingface dataset:
In‐Season Prediction of Corn Grain Yield Potential Using Normalized Difference Vegetation Index
Authors: Teal R. K. , Tubana B. , Girma K. , Freeman K. W. , Arnall D. B. , Walsh O. , Raun W. R.
Published: October 2006

Drastic increases in the cost of N fertilizer and increased public scrutiny have encouraged development and implementation of improved N management practices. This study evaluated the relationship between corn (Zea mays L.) grain yield and early season normalized difference vegetation index (NDVI) sensor readings using the GreenSeeker sensor. The relationships between grain yield and several predictor variables were determined using linear and nonlinear regression analysis. Categorizing NDVI measurement by leaf stage indicated that growth stage was critical for predicting grain yield potential. Poor exponential relationships existed between NDVI from early sensor measurements (V6–V7 leaf stage) and grain yield. By the V8 stage, a strong relationship (R2 = 0.77) was achieved between NDVI and grain yield. Later sensor measurements (V9 and later) failed to distinguish variation in green biomass as a result of canopy closure. Normalizing the NDVI with GDD (growing degree days) did not significantly improve yield potential prediction (R2 = 0.73), but broadened the yield potential prediction equation to include temperature and allowed for adaptation into various climates. Sensor measurements at the range of 800 to 1000 GDD resulted in a significant exponential relationship between grain yield and NDVI (R2 = 0.76) similar to the V8 leaf stage categorization. Categorizing NDVI by GDD (800–1000 GDD) extended the sensing time by two additional leaf stages (V7–V9) to allow a practical window of opportunity for sidedress N applications. This study showed that yield potential in corn could be accurately predicted in season with NDVI measured with the GreenSeeker sensor.
Do Productivity and Environmental Trade‐offs Justify Periodically Cultivating No‐till Cropping Systems?
Authors: Grandy A. S. , Robertson G. P. , Thelen K. D.
Published: October 2006

No‐till management has been shown to increase soil aggregation, reduce erosion rates, and increase soil organic matter across a range of soil types, cropping systems, and climates. Few agricultural practices provide similar opportunities to deliver positive benefits for farmers, society, and the environment. The potential benefits of no‐till are not being fully realized, however, in large part because no‐till is rarely practiced continuously and many fields suitable for no‐till are still conventionally tilled. We present here three arguments, based on recent research, in support of the agronomic and environmental benefits of continuous no‐till: (i) although there exist agronomic challenges with no‐till, long‐term yields in these systems can equal or exceed those in tilled soils; (ii) cultivating no‐till systems can decrease soil aggregation and accelerate C and N losses so rapidly that years of soil restoration can be undone within weeks to months; and (iii) over time, changes in soil structure and organic matter, coupled with producer adaptation to the need for spatially and temporally explicit chemical applications, increase plant N availability and reduce environmental N losses. At least in theory, then, continuous no‐till can be widely practiced to improve the environment and maintain yields with little or no economic sacrifice by producers. In practice, however, many diverse challenges still limit no‐till adoption in different regions. These challenges are surmountable, but potential solutions need to be interdisciplinary and address the ecological and especially the social and economic constraints to deploying continuous no‐till.
Low‐gravity combustion synthesis: Theoretical analysis of experimental evidences
Authors: Locci A. M. , Licheri R. , Orrù R. , Cincotti A. , Cao G. , De Wilde J. , Lemoisson F. , Froyen L. , Beloki I. A. , Sytschev A. E. , Rogachev A. S. , Jarvis D. J.
Published: October 2006

The results obtained during a parabolic flight campaign sponsored by ESA on March 2002, and related to the combustion synthesis of TiB2 − xTiAl and TiB2 − xTiAl3 composites are reported. Besides classical SHS experiments performed using cylindrical pellets, combustion front quenching experiments using conical samples placed inside a copper block are also conducted. Similar experiments are carried out under terrestrial conditions, for the sake of comparison. As expected, under both low‐gravity and terrestrial conditions, it is found that combustion temperature and front propagation velocity decrease as the system exothermicity is reduced, that is, when the aluminide/diboride molar ratio is augmented. However, it is observed that reaction front propagates relatively slower under low‐gravity conditions. Consistently, the extinction of the combustion front occurs earlier when the reaction is performed under reduced gravity conditions. A theoretical analysis performed by means of appropriate dimensionless numbers is proposed to provide possible explanations of the main experimental evidences reported in the literature on this subject, including those shown in this work. Specifically, this analysis reveals that the relatively higher‐propagation velocity observed under terrestrial conditions may be due to the correspondingly lower‐sample porosity change, which in turn limits the thermal conductivity decreasing in the reaction zone. In addition, free convection phenomena taking place in the molten phase formed at the reaction zone are able to justify the difference in combustion wave velocity experimentally observed under terrestrial conditions between top and bottom ignition configurations. Moreover, it is found that finer microstructure typically observed under low‐gravity is likely a consequence of the reduced coalescence phenomena taking place in such conditions. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Core binding factor beta (CBFB) haploinsufficiency due to an interstitial deletion at 16q21q22 resulting in delayed cranial ossification, cleft palate, congenital heart anomalies, and feeding difficulties but favorable outcome
Authors: Khan Aneal , Hyde R. Katherine , Dutra Amalia , Mohide Patrick , Liu Paul
Published: October 2006

The core binding factor beta gene (CBFB), essential to bone morphogenesis, is located at 16q22.1. Homozygous deficiency of CBFB leads to ossification defects in mice. CBFB forms a heterodimer with RUNX2 (CBFA1) during embryonic bone development. RUNX2 mutations lead to cleidocranial dysplasia in humans. We describe an infant boy with an interstitial deletion of 16q21q22, delayed skull ossification, cleft palate, and heart anomalies who had a difficult course in infancy but eventually improved and is healthy. He was found to have CBFB haploinsufficiency, but did not have mutations in RUNX2. We suggest that 16q21q22 deletion be considered when there are antenatal or postnatal findings of enlarged cranial sutures with or without cleft palate. The finding of CBFB haploinsufficiency in our case and the similarity of cranial ossification defects with a mouse model of CBFB deletion suggest a role for CBFB in cranial bone development in humans. © 2006 Wiley‐Liss, Inc.
Impact of highly active antiretroviral therapy on outcome of cholecystectomy in patients with human immunodeficiency virus infection
Authors: Foschi D , Cellerino P , Corsi F , Casali A , Rizzi A , Righi I , Trabucchi E
Published: October 2006

Background

Highly active antiretroviral therapy (HAART) reduces virus proliferation and significantly decreases the rate of septic and opportunistic complications in patients infected with human immunodeficiency virus (HIV). Although surgery is performed routinely on patients receiving HAART, the effect of this treatment on surgical outcome has not been examined in detail.

Methods

This retrospective study reviewed 54 consecutive patients with HIV infection who underwent surgical cholecystectomy: 31 patients were on HAART, 13 on nucleoside analogue reverse transcriptase inhibitors (NRTIs) and ten were receiving no specific therapy. Characteristics of HIV-1 infection, laboratory investigations, characteristics of the gallbladder disease, type of operation, postoperative course, morbidity and mortality were recorded. Univariable analysis and unconditional logistic regression were performed to determine factors related to postoperative complications and death.

Results

The three groups were similar in terms of HIV-1 infection characteristics. In univariable analysis HAART and laparoscopic cholecystectomy were associated with a significantly lower complication rate, whereas only HAART was shown to be protective by logistic regression analysis. A low HIV RNA load and a high CD4+ cell count were significant predictors of uncomplicated surgical outcomes.

Conclusion

HAART significantly reduces the risk of complications after cholecystectomy in patients with HIV infection or acquired immune deficiency syndrome.
Binding of regulatory protein omega from Streptococcus pyogenes plasmid pSM19035 to direct and inverted 7‐base pair repeats of operator DNA
Authors: Dostál Lubomír , Pratto Florencia , Alonso Juan C. , Welfle Heinz
Published: October 2006

pSM19035‐encoded dimeric regulator omega (ω2) belongs to the MetJ/Arc family of ribbon–helix–helix DNA binding proteins. ω2 binds to a set of unspaced 7‐base pair repeat units with sequence 5′‐A/TATCACA/T‐3′. Protein ω2 and its variant ω2ΔN18, lacking the first 18 N‐terminal amino acids, bind poorly to one heptad DNA, but the affinity to DNA markedly increases with two and more heptads organized in direct or inverted orientation. Raman difference spectra indicate that ω2 and ω2ΔN18 bind to operator DNA in the major groove and contact thymine, adenine and guanine residues. The mode of ω2 or ω2ΔN18 interaction with operator DNA is not affected by the orientation and number of heptads. The Raman data of ω2T29A, an ω2 variant with Ala instead of Thr at position 29 of the β‐sheet, show a sequence‐independent binding mode to DNA, which differs from the binding mode of wt ω2 protein to its cognate site. The Raman data strongly support the notion that the 18 N‐terminal amino acids are not required for ω2 activity, whereas Thr29 plays an essential role for operator DNA binding. The data suggest the formation of a hydrogen bond between Thr29 of wild‐type ω2 to one of the bases in the central 5′‐TCA‐3′/5′‐TGA‐3′ stretch of the 7‐bp binding site. Copyright © 2006 John Wiley & Sons, Ltd.
Changes in spectral features with varying mole fractions of anisaldehyde in binary mixtures
Authors: Anis Fathima A. , Umadevi M. , Ramakrishnan V.
Published: October 2006

Raman and IR spectra of neat anisaldehyde (4‐methoxybenzaldehyde (4MeOBz)) and its binary mixtures (in polar and nonpolar solvents) with varying mole fraction of 4MeOBz were investigated. The concentration dependence of the wavenumber position and line width (full width at half maximum, FWHM) was analyzed to study the interaction of the solute vibrational modes with the microscopic solvent environment. The wavenumbers of Raman modes of 4MeOBz, namely, the carbonyl stretching, aldehydic δ (CH) and ring‐breathing modes, showed a linear variation in the peak position for varying concentrations of 4MeOBz in the different solvents. The dependence of Raman line width with concentration of 4MeOBz of these modes was also taken into account. The solute–solvent interaction is stronger in 2‐propanol and acetonitrile because of the formation of hydrogen bonds between them, whereas in benzene the interaction is too weak to affect the Raman modes. The modes, ν (CO) in 2‐propanol and aldehydic δ (CH) in acetonitrile, gave a Gaussian‐type line width variation, which was explained by the concentration fluctuation model, and the linear variation of the line widths was also interpreted by solute–solvent interactions. IR spectra were taken for these binary mixtures, which also give further support to these data. Copyright © 2006 John Wiley & Sons, Ltd.
A spectroscopic resolution of the structure of Zn(CN)2
Authors: Ravindran T. R. , Arora A. K. , Sairam T. N.
Published: October 2006

Two different cubic structures of the negative thermal expansion (NTE) material zinc cyanide have been reported in the literature: one, an ordered structure (space group P43m) in which the ZnC4 tetrahedra are linked to neighbouring ZnN4 tetrahedra with CN bonds and vice versa, and the other, a disordered structure (space group Pn43m) where N and C sites are indistinguishable. Here, we present group theoretical analyses to classify the phonons of different symmetries in the two structures and report Raman and infrared spectroscopic studies to resolve the ambiguity about the structure. On the basis of the number of Raman and IR modes expected and observed, we conclude that the compound exists in a disordered structure. Copyright © 2006 John Wiley & Sons, Ltd.
Literal‐paraconsistent and literal‐paracomplete matrices
Authors: Lewin Renato A. , Mikenberg Irene F.
Published: October 2006

We introduce a family of matrices that define logics in which paraconsistency and/or paracompleteness occurs only at the level of literals, that is, formulas that are propositional letters or their iterated negations. We give a sound and complete axiomatization for the logic defined by the class of all these matrices, we give conditions for the maximality of these logics and we study in detail several relevant examples. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Chemical modification of therapeutic drugs or drug vector systems to achieve targeted therapy: Looking for the grail
Authors: Juillerat‐Jeanneret L. , Schmitt F.
Published: October 2006

Most therapeutic drugs distribute to the whole body, which results in general toxicity and poor acceptance of the treatments by patients. The targeted delivery of chemotherapeutics to defined cells, either stromal or cancer cells in cancer lesions, or defined inflammatory cells in immunological disorders, is one of the main challenges and a very active field of research in the development of treatment strategies to minimize side‐effects of drugs. Disease‐associated cells express molecules, including proteases, receptors, or adhesion molecules, that are different or differently expressed than their normal counterparts. Therefore one goal in the field of targeted therapies is to develop chemically derivatized drugs or drug vectors able to target defined cells via specific recognition mechanisms and also able to overcome biological barriers. This article will review the approaches which have been explored to achieve these goals and will discuss in more detail three examples (i) the use of nanostructures to take advantage of increased vascular permeability in some human diseases, (ii) the targeting of therapeutic drugs to an organ, the brain, protected against foreign molecules by the blood–brain barrier, and (iii) the use of the folate receptor to target either tumor cells or activated macrophages. © 2006 Wiley Periodicals, Inc. Med Res Rev, 27, No. 4, 574–590, 2007
Identification of new claudin family members by a novel PSI‐BLAST based approach with enhanced specificity
Authors: Wu Jun , Helftenbein Gerd , Koslowski Michael , Sahin Ugur , Tureci Özlem
Published: October 2006

In an attempt to develop a novel strategy for the identification of new members of protein families by in silico approaches, we have developed a semi‐automated procedure of consecutive PSI‐BLAST (Position‐Specific‐Iterated Basic Local Alignment Search Tool) searches incorporating identificiation as well as subsequent validation of putative candidates. For a proof of concept study we chose the search for novel members of the claudin family. The initial step was an iterated PSI‐BLAST search starting with the PMP22_Claudin domain of each known member of the claudin family against the human part of the RefSeq Database. Putative new claudin domains derived from the converged list were evaluated by a validating PSI‐BLAST in which each sequence was assessed for finding back the starting set of known claudin domains. The local PSI‐BLAST searches and validation were automated by a set of PERL scripts. With this strategy a total of three additional putative claudin domains in three different proteins were identified. One of them was subjected to further characterization and was shown to exhibit claudin‐like features in terms of protein structure and expression pattern. The strategy we present is an efficient and versatile tool to identify novel members of domain‐sharing protein families. Low rates of false positives achieved by inclusion of a validation step into the in silico procedure make this strategy particularly attractive to select candidates for subsequent labor‐intensive wet bench characterization. Proteins 2006. © 2006 Wiley‐Liss, Inc.
The use of passive seismic protection in structural rehabilitation
Authors: Guerreiro L. , Craveiro A. , Branco M.
Published: October 2006

In the recent years, many technologies of seismic protection have been developed in an attempt to mitigate the effects of earthquakes on buildings or other structures. The most important examples of seismic protection technology are the base isolation and the use of energy dissipators. A great majority of applications of this type of seismic protection had been done in new structures, and there are already a significant number of examples of the use of these technologies in seismic rehabilitation all over the world.

In this paper, the analyses of the different types of seismic passive protection and their possibilities of use in structural rehabilitation is presented. The rehabilitation of structures from the old masonry historic buildings to more recent reinforced concrete buildings is discussed.

Two studies of seismic rehabilitation with passive protection are presented. The first study is the rehabilitation of an old masonry lighthouse (‘Farol dos Capelinhos’, Azores) using base isolation. This structure had been affected by an earthquake and volcano eruption and needed to be reinforced. One of the studied solutions was the use of seismic base isolation at the base of the Lighthouse tower. This study and its results are presented in the paper.

The second study is the rehabilitation of an old masonry building with the use of viscous dampers. This building is an example of an important part of the existing building stock of Lisbon, commonly designated by ‘Gaioleiros’. This type of buildings were constructed in the period between the end of the 19th century and the start of the 20th century, and are composed of exterior masonry walls with wood infill panels and wooden floors. This kind of structures are particularly vulnerable to the seismic action and are objects of different studies for possible retrofit interventions.
Application of Small Molecule Microarrays in Comparative Chemical Proteomics
Authors: Molnár Eszter , Hackler László , Jankovics Tamás , Ürge László , Darvas Ferenc , Fehér Liliána Z. , Lőrincz Zsolt , Dormán György , Puskás László G.
Published: October 2006

The simultaneous identification of disease‐specific protein targets and their small molecule‐binding partners, suitable as drug candidates, could radically reduce the timeline and costs of drug discovery and development. Comparative chemical proteomics provides a novel approach to achieve this goal through rapid detection of overexpressed proteins in diseased samples by the application of small molecule microarrays. The interacting small molecules enable direct affinity‐based isolation and identification of the proteins. In the present paper we report comparative chemical proteomics studies on melanocytes and melanoma cell‐lines, which led to the identification of three overexpressed proteins together with their small molecule‐binding partner.
Global existence for a nonlinear Schroedinger–Chern–Simons system on a surface
Authors: Demoulini Sophia
Published: October 2006

Global existence of regular solutions for a nonlinear Schroedinger–Chern–Simons system of equations on a two-dimensional compact Riemannian manifold is proved.

L'existence d'une solution globale régulière est démontrée pour un système non-linéaire d'équations de Schroedinger–Chern–Simons sur une variété Riemannienne compacte de deux dimensions.
Editorial
Authors: BALME CHRISTOPHER B.
Published: October 2006

With the publication of this issue my period as editor of TRI comes to an end. I was fortunate in being able to inherit from my predecessor, Brian Singleton, a flourishing academic journal that had attained a reputation for academic excellence combined with a broad international perspective. I am often asked to define TRI in comparison to other affined periodicals. This is a difficult but nonetheless important question, not only for the editorial board but also for potential authors. If we look at the policy statement (on the inside back cover) then we find a very broad remit: ‘articles on theatre practices in their social, cultural, and historical contexts’ but also, and perhaps more particularly, a desire to reflect ‘the evolving diversity of critical idioms prevalent in the scholarship of differing world contexts’. The last three words are perhaps the most important in respect to the journal's specific focus. TRI is dedicated to reflecting theatre and performance internationally; it gives special preference to articles outside the usual Euro-American mainstream. In this sense the journal aims to reflect the diversity of the membership of the International Federation for Theatre Research/Fédération internationale pour la recherche théâtrale. It is not, however, a mouthpiece of the organization or any of its constituent bodies. Editorial independence is essential for the functioning of any peer-reviewed journal lest it be seen as catering to interest groups or persons whose political prowess may far exceed their scholarly standing.
The squirrel as a rodent model of the human visual system
Authors: VAN HOOSER STEPHEN D. , NELSON SACHA B.
Published: October 2006

Over the last 50 years, studies of receptive fields in the early
mammalian visual system have identified many classes of response
properties in brain areas such as retina, lateral geniculate nucleus
(LGN), and primary visual cortex (V1). Recently, there has been
significant interest in understanding the cellular and network mechanisms
that underlie these visual responses and their functional architecture.
Small mammals like rodents offer many advantages for such studies, because
they are appropriate for a wide variety of experimental techniques.
However, the traditional rodent models, mice and rats, do not rely heavily
on vision and have small visual brain areas. Squirrels are highly visual
rodents that may be excellent model preparations for understanding
mechanisms of function and disease in the human visual system. They use
vision for navigating in their environment, predator avoidance, and
foraging for food. Visual brain areas such as LGN, V1, superior
colliculus, and pulvinar are particularly large and well elaborated in the
squirrel, and the squirrel has several extrastriate cortical areas lateral
to V1. Unlike many mammals, most squirrel species are diurnal with
cone-dominated retinas, similar to the primate fovea, and have excellent
dichromatic color vision that is mediated by green and blue cones. Owing
to their larger size, squirrels are physiologically more robust than mice
and rats under anesthesia, and some hibernating species are particularly
tolerant of hypoxia that occurs during procedures such as brain slicing.
Finally, many basic anatomical and physiological properties in the early
visual system of squirrel have now been described, permitting
investigations of cellular mechanisms. In this article, we review four
decades of anatomical, behavioral, and physiological studies in squirrel
and make comparisons with other species.
Processing of first-order motion in marmoset visual cortex is
influenced by second-order motion
Authors: BARRACLOUGH NICK , TINSLEY CHRIS , WEBB BEN , VINCENT CHRIS , DERRINGTON ANDREW
Published: October 2006

We measured the responses of single neurons in marmoset visual cortex
(V1, V2, and the third visual complex) to moving first-order stimuli and
to combined first- and second-order stimuli in order to determine whether
first-order motion processing was influenced by second-order motion. Beat
stimuli were made by summing two gratings of similar spatial frequency,
one of which was static and the other was moving. The beat is the product
of a moving sinusoidal carrier (first-order motion) and a moving
low-frequency contrast envelope (second-order motion). We compared
responses to moving first-order gratings alone with responses to beat
patterns with first-order and second-order motion in the same direction as
each other, or in opposite directions to each other in order to
distinguish first-order and second-order direction-selective responses. In
the majority (72%, 67/93) of cells (V1 73%, 45/62; V2 70%,
16/23; third visual complex 75%, 6/8), responses to first-order
motion were significantly influenced by the addition of a second-order
signal. The second-order envelope was more influential when moving in the
opposite direction to the first-order stimulus, reducing first-order
direction sensitivity in V1, V2, and the third visual complex. We
interpret these results as showing that first-order motion processing
through early visual cortex is not separate from second-order motion
processing; suggesting that both motion signals are processed by the same
system.
Investigating the kinematics of mountain building in Taiwan from the spatiotemporal evolution of the foreland basin and western foothills
Authors: Simoes Martine , Avouac Jean Philippe
Published: October 2006

The Taiwanese range has resulted from the collision between the Luzon volcanic arc and the Chinese continental margin, which started about 6.5 Myr ago in the north, and has since propagated southward. The building of the range has been recorded in the spatiotemporal evolution of the foreland basin. We analyze this sedimentary record to place some constraints on the kinematics of crustal deformation. The flexure of the foreland under the load of the growing wedge started with a 1.5 Myr long phase of rapid subsidence and sedimentation, which has migrated southward over the last 3.5 Myr at a rate of 31 +10/−5 mm/yr, reflecting the structural evolution of the range and the growth of the topography during the oblique collision. Isopachs from the Toukoshan (∼0 to 1.1 Ma) and Cholan (∼1.1 to 3.3 Ma) formations, as well as the sedimentation rates retrieved from a well on the Pakuashan anticline, indicate that the foreland basement has been moving toward the center of mass of the orogen by ∼45–50 mm/yr during the development of the basin. From there, we estimate the long‐term shortening rate across the range to 39.5–44.5 mm/yr. By considering available data on the thrust faults of the foothills of central Taiwan, we show that most (if not all) the shortening across the range is accommodated by the most frontal structures, with little if any internal shortening within the wedge. The range growth appears therefore to have been essentially sustained by underplating rather than by frontal accretion. In addition, only the upper ∼7 to 9 km of the underthrusted crust participates to the growth of the orogen. This requires that a significant amount of the Chinese passive margin crust is subducted beneath the Philippine Sea plate.
Tropospheric ozone and El Niño–Southern Oscillation: Influence of atmospheric dynamics, biomass burning emissions, and future climate change
Authors: Doherty R. M. , Stevenson D. S. , Johnson C. E. , Collins W. J. , Sanderson M. G.
Published: October 2006

We investigate how El Niño Southern Oscillation (ENSO) influences tropospheric ozone and its precursors in a coupled climate‐chemistry model. As shown in similar studies, tropospheric column ozone (TCO) decreases in the central and east Pacific and increases in the west Pacific/Indonesia in response to circulation and convective changes during El Niño conditions. Simulated changes in TCO for “peak” El Niño events in the central and east Pacific are in good agreement but are underestimated in the west Pacific compared to previous observational and modeling studies for October 1997. Tropospheric column‐average NOx decreases over Indonesia and generally over South America as a result of suppressed convection and lightning over these land regions. NOx and HOx changes during El Niño modify ozone chemical production and destruction. When we include annually varying biomass burning emissions in our model simulations we find that these emissions peak over Indonesia 1–2 months in advance of the peak elevated sea‐surface temperatures (SSTs) and hence the “meteorological” El Niño. We underestimate the strength of the TCO increase due to El Niño–related dry conditions over Indonesia in October 1997 compared to observations. We also examine how future mean and variability changes in ENSO, as simulated in the HadCM3 climate model, impacts tropospheric ozone. A mean future El Niño–like state is simulated in the tropical Pacific in HadCM3, but this has no discernable impact on the future TCO trend in this region. However, we do simulate increased variability in precipitation and TCO related to ENSO in the future.
Vector properties of the O(D21) fragment produced from the photolysis of ozone in the wavelength range of 298to320nm
Authors: Horrocks S. J. , Pearson P. J. , Ritchie G. A. D.
Published: October 2006

The speed averaged translational anisotropy and electronic angular momentum polarization of the O(D21) atomic fragment formed from the photodissociation of ozone in the atmospherically important long wavelength region of the Hartley band (298to320nm) have been measured using resonance enhanced multiphoton ionization time of flight mass spectrometry. The translational anisotropy parameter, β, is found to decline from 1.1 for photolysis at 300nm to a minimum value of 0 at 310nm which is the threshold for production of O(D21) in conjunction with the O2(aΔg1v=0) molecular cofragment. For photolysis wavelengths greater than 310nm, O(D21) is formed from the dissociation of internally excited ozone molecules. The corresponding β parameters are markedly lower than for atomic fragments produced with the same speed from the photolysis of ground state ozone molecules. This result is consistent with two different pathways contributing to the photolysis of internally excited ozone at the longest wavelengths studied corresponding to initial internal excitation either in the symmetric or asymmetric stretching vibration. In addition, the polarization of the atomic angular momentum has been determined with the incoherent polarization parameters a02(‖) and a02(⊥) increasing from values of −0.53 and −0.62 at 300nm to −0.37 and −0.19 at 317nm, consistent with the increasing contribution from the photolysis of internally excited ozone as the dissociation wavelength lengthens. Evaluation of these alignment parameters allows the populations of the magnetic substrates, mj, to be determined. For example, for a photolysis wavelength of 303nm the populations of mj=0,±1,±2 are in the ratio of 0.36: 0.56: 0.08 and this ratio is essentially independent of the photolysis wavelength. The coherent contribution to the atomic polarization is quantified by the Re{a12(‖,⊥)} and Im{a11(‖,⊥)} parameters and these are found to vary from −0.21 and 0.21 at 300nm to −0.04 and 0.24 at 313nm, respectively.
Andreev spectroscopy of point contacts between a low-temperature superconductor and manganite
Authors: D’yachenko A. I. , Krivoruchko V. N. , Tarenkov V. Yu.
Published: October 2006

Andreev reflection in contacts between a low-temperature superconductor (Pb or MgB2) and the manganite La0.65Ca0.35MnO3 (LCMO) is investigated. In the majority of cases behavior typical of superconductor/half-metallic ferromagnet contacts is observed: an excess voltage Vexc and suppression of the contact conductance G(V)=dI(V)∕dV in the region of voltages e∣V∣≤ΔS, where ΔS is the energy gap of the injector. However, some of the contacts demonstrate an increase of the conductance and an excess current Iexc on the current–voltage characteristic of the contact at e∣V∣≤ΔS. The character of the dI(V)∕dV curves observed for those contacts corresponds to Andreev spectrum of a superconductor with an energy gap much larger than the injector gap ΔS. It is assumed that in contacts of the latter type, specific conditions prevail whereby the penetration of Cooper pairs into the manganite from an electrode with a singlet order parameter induces in the surface region of the manganite a superconducting state with a triplet type of correlations.
Novel advanced Gundestrup-like probe for the measurements of flows and edge plasma parameters in TEXTOR
Authors: Peleman P. , Jachmich S. , Xu Y. , Boucher C. , Van Oost G. , Schweer B. , Mitri M.
Published: October 2006

A novel advanced Gundestrup-like probe head for local measurements of equilibrium and fluctuating plasma parameters in the plasma edge of TEXTOR is described. This probe assembly enables us to simultaneously determine the toroidal and poloidal plasma flows, the ion saturation current, density, electron temperature, floating potential, as well as their fluctuating properties. An improved analytical probe model is used to correctly relate the ratio of the ion saturation currents measured at the upstream and downstream collecting surfaces to the plasma flow. The probe is mounted on a fast reciprocating manipulator resulting in a high radial resolution of the profiles. A unique feature of the fast probe is the electrical linear motor drive which allows predefining any wave form of the radial position. The high speed of the probe drive reduces the exposure time which enables us to measure several radial profiles within a single discharge deep inside the last closed flux surface. We describe the first experimental results of flow, radial electric field, ion density, and temperature profiles measured in the plasma edge of TEXTOR. In order to verify the accuracy of these measured quantities we compare the measured radial electric field with the one calculated from the single ion momentum balance equation.
Novel fast-neutron activation counter for high repetition rate measurements
Authors: Mahmood S. , Springham S. V. , Zhang T. , Rawat R. S. , Tan T. L. , Krishnan M. , Beg F. N. , Lee S. , Schmidt H. , Lee P.
Published: October 2006

A fast-neutron beryllium activation counter has been constructed for neutron measurements on a high repetition rate deuterium plasma focus. Beryllium activation is especially suitable for measurements of DD neutron yields. The cross section for the relevant reaction, Be9(n,α)He6, results in a maximum sensitivity at the characteristic energy of the DD neutrons (∼2.5MeV) and practically no sensitivity to neutrons with energies <1MeV. The short half-life (0.8s) for the decay of He6 enabled the shot-to-shot neutron yield from the plasma focus to be measured for repetition rates from 0.2to3Hz (and for a range of deuterium gas pressures). With careful analysis, the shot-to-shot yield can be measured up to a maximum repetition rate of 3Hz, beyond which the pileup of counts from the previous shots reduces the accuracy of the measurements to an unacceptable level. This new beryllium activation counter has been cross-checked against an indium activation counter to obtain absolute neutron yields. At a charging voltage of 12.5kV (bank energy of 2.2kJ), the average neutron yield was found to be (7.9±0.7)×107 per shot (standard deviation of 4×107). It was found that activation of the plasma focus construction materials (especially aluminum) must be taken into account.
External magnetic diagnostics for the National Compact Stellarator Experiment
Authors: Stratton B. , Brooks A. , Brown T. , Johnson D. , Labik G. , Lazarus E. , Pomphrey N. , Raftopoulos S. , Zarnstorff M.
Published: October 2006

The National Compact Stellarator Experiment will have a complete set of magnetic diagnostics to constrain equilibrium reconstructions and for plasma control. The flux loops lying on the exterior surface of the vacuum vessel and the flux loops cowound with the field coils must be installed during machine construction because they will later be inaccessible. Designs and installation techniques for these diagnostics are described.
Neutron imaging of inertial confinement fusion target plasmas using high-resolution gel bubble detectors
Authors: Fisher R. K.
Published: October 2006

Recently developed gel bubble detectors with higher detection efficiency look attractive for high-resolution neutron imaging of inertial confinement target plasmas. Bubble detectors can detect neutrons with a spatial resolution as small as 5μm. By allowing high-resolution imaging of National Ignition Facility (NIF) and Laser MegaJoule (LMJ) Facility targets without the need for ⩾25m line-of-sight paths, bubble detectors should allow views in multiple and orthogonal directions from the target. Earlier proof-of-principle tests on OMEGA were limited by the very low (8×10−6bubbles∕n) detection efficiency of the then available gel detectors. Detectors with ∼100 times higher efficiency per centimeter of thickness are now available. At the high bubble densities expected in the new detectors, the spatial distribution of the bubbles must be measured by a line integral technique such as x-ray transmission. This avoids the need for optically transparent detectors, allowing much higher densities of superheated drops, smaller drop diameters, and detector thicknesses of several centimeters. It now appears that high-resolution images of NIF and LMJ target plasmas at neutron yields ⩾1013 may be possible using high efficiency gel bubble detectors.
Photodissociation of nitrous oxide starting from excited bending levels
Authors: Kawamata Hiroshi , Kohguchi Hiroshi , Nishide Tatsuhiro , Suzuki Toshinori
Published: October 2006

The photodissociation dynamics of N2O in the wavelength region of 203–205nm was studied by velocity map ion imaging. A speed resolution of 0.8% was obtained using standard projection imaging and subpixel centroiding calculations. To investigate N2O dissociation starting from the excited bending levels in the ground electronic state, a supersonic molecular beam and an effusive beam were used. The photoabsorption transition probability from the first excited bending level in the wavelength region of 203–205nm was estimated to be seven times greater than that from the ground vibrational level.
Inelastic scattering from glyoxal: Collision kinematics rather than the interaction potential dominates rotational channel selection
Authors: Clegg Samuel M. , Parmenter Charles S.
Published: October 2006

Relative cross sections have been obtained for the rotationally and rovibrationally inelastic scattering of S1 trans-glyoxal (CHO–CHO) in its zero point level with K′=0 from the target gases H2, D2, and He. Emphasis is placed on using crossed molecular beam conditions that provide several choices of collision kinematics (center-of-mass collision energy, relative velocity, center-of-mass collision momentum) for each collision pair. The cross sections define the state-to-state competition among numerous rotational channels involving destination states with ΔK′ ranging from 1 to >15 for collisions with each target gas and under every kinematic condition. They also resolve a similar rotational competition among rovibrational channels where the torsion ν7′ is collisionally excited. The cross section sets also allow the relative overall magnitudes of the two types of scattering to be compared. The primary motivation of these experiments concerns the rotationally inelastic scattering. Earlier studies with rare gases and fixed kinematics demonstrated that the distribution of rotational cross sections is remarkably similar from one collision pair to another. The new data show that the competition among rotational channels actually has a small but distinct dependence on kinematic conditions. Data analysis shows that the dependence is a systematic function of the available collision momentum and entirely unrelated to the identity of the target gases, including the heavier rare gases used in earlier studies. The competition among the rotational energy transfer channels and its kinematic heritage is discussed in the context of a classical hard ellipse model of linear momentum to angular momentum conversion much used with room temperature systems. When adapted to our beam conditions, the resulting account of the rotational scattering is accurate and provides insight into the collisional details.
Room-temperature ferrimagnetic semiconductor 0.6FeTiO3∙0.4Fe2O3 solid solution thin films
Authors: Hojo Hajime , Fujita Koji , Tanaka Katsuhisa , Hirao Kazuyuki
Published: October 2006

The authors report on the fabrication of room-temperature ferrimagnetic semiconductor thin films composed of 0.6FeTiO3∙0.4Fe2O3 solid solution on α-Al2O3 (0001) substrates using a pulsed laser deposition method. A single ordered phase (R3¯ symmetry) is obtained under very limited deposition conditions including oxygen partial pressure of 2.0×10−3Pa and substrate temperature of 700°C. The thin film with the ordered phase is an n-type semiconductor and ferrimagnetic with the Curie temperature >400K. The Hall effect measurements at room temperature suggest that the carrier spins are polarized.
Presentation of a Visual Nearby Moving Object Alters Stream/Bounce Event Perception
Authors: Kawachi Yousuke , Gyoba Jiro
Published: October 2006

Two identical visual objects moving across each other in a two-dimensional display can be perceived as either streaming through or bouncing off each other. The bouncing event percept is promoted by the presentation of a brief sound at the point of coincidence of the two objects. In this study, we examined the effect of the presence of a moving object near the two objects as well as the brief sound on the stream/bounce event perception. When both the nearby moving object and brief sound were presented, a streaming event, not a bouncing event, was robustly perceived (experiment 1). The percentage of the streaming percept was also systematically affected by the proximity of the nearby object (experiment 2). These results suggest that the processing of intramodal grouping between a nearby moving object and either of the two objects in the stream/bounce display interferes with crossmodal (audiovisual) processing. Moreover, we demonstrated that, depending on the trajectory of the nearby moving object, the processing of intramodal grouping can promote the bouncing percept, just as crossmodal processing does (experiment 3).
The chloro and bromo complexes of iridium(III) and iridium(IV). II. Structural chemistry of IrIII complexes
Authors: Rankin DA , Penfold BR , Fergusson JE
Published: October 2006

The single-crystal X-ray
structures of the tervalent iridium complexes K3
[IrCl6] [P1, a 1263.1, b 7029, c 702.7 pm, Ir-Cl(mean) 236.8 pm], K3
[IrCl6].H2O [C1 (1), a 1243.6, b 1568.2, c 1207.2 pm, Ir-Cl
(mean) 236.8 pm], (NH4)3 [IrCl6].H2O
[Cs(m), a 1222.9, b 701.1 c, 1408.8 pm, Ir-Cl (mean) 236.7 pm] and
Rb3 [IrBr,].H2O [Pnma, a 1276.8, b 739.1, c 1498.2pm, Ir-Br(mean) 250.8 pm] have
been determined. From preliminary single-crystal studies, and X-ray powder
diffraction, the structures of a number of other hexachloro
and hexabromo complexes of IrIII have been
determined. In all cases the halogeno anions are
distorted as a consequence of the non-spherical packing of the cations and in
some cases water molecule around the anions.
The reactivity of p-nitrophenyl esters with surfactants in apolar solvents. VI. Structural effects on the reaction of p-nitrophenyl acetate with alkanediamine bis(dodecanoate) salts
Authors: O'Conner CJ , Lomax TD
Published: October 2006

The rate of decomposition
of p-nitrophenyl
acetate has been measured in benzene solutions of a series of alkane-α,ω-diamine bis(dodecanoate)
salts.
Me(CH2)10CO2-+NH3(CH2)NH3N+ -O2C(CH2)10ME(n=2-7,9,10,12)
The micellar rate constant
is affected by the diamine chain length, and the
bimolecular rate constant is affected both by the chain length (and whether the
number of carbon atoms is even or odd) and by the acidity of the diammonium head groups. The Br�nsted
plot is linear but the slope in creases with increasing detergent
concentration.
Bicyclo[2.2.2]octane-2,5-carbolactone
Authors: Brecknell DJ , Carman RM , Day PJ
Published: October 2006

The title compound has been
synthesized and compared with bicyclo[2.2.2]octane-2,6-carbolactone.
Ambiguities in the literature concerning the preparation of the title compound
have been resolved.
An Improved Equation for the Liquid Junction Potential at the Interface of Different Solvents
Authors: Berne A , Kahanda C , Popovych O
Published: October 2006

The component of the liquid-junction potential due to the diffusion of ions across an interface of electrolyte solutions in different solvents was formulated by taking into account the solvent dependence of the transport numbers, t, and of the chemical potentials of ions in the interphase region as determined from experimental data on their variation in the mixed-solvent compositions. The new equation was applied to NaCl/NaCl and HCl/HCl junctions between water and methanol-water solvents over the entire solvent range. Significant differences between the results obtained with the new equation and the old formulation, which treated the transport numbers as solvent-independent, were observed only for the HCl junctions involving 90-100 wt % aqueous methanol, where tH exhibits a sharp minimum as a function of the solvent composition.
The Constituents of Marine Sponges. VI. Diterpenoid Metabolites of the New Zealand Sponge Chelonaplysilla violacea
Authors: Bergquist PR , Bowden BF , Cambie RC , Craw PA , Karuso P , Poiner A , Taylor WC
Published: October 2006

The sponge Chelonaplysilla violacea, collected from New Zealand coastal waters, contains as major constituents the diterpenoids aplyviolene (1a), norrisolide (2), dendrillolide A (3) aplyroseol-7 (4), spongian-16-one (5), chelonaplysin C (6), and a series of new compounds cheloviolene A-F and cheloviolin. Structures were assigned to cheloviolene A (7),
[3aR-[3aα,4α(1R*,3aR*,8aS*),5β,6aα]]-5-hydroxy-4(1,4,4-trimethyl-8-methylenedecahydroazulen-1-yl) tetrahydrofuro [2,3- b] furan-2(3H)-one, cheloviolene B (8), [3aR-[3aα,4a(1R*,3aR*, 8aS*),5α,6aα]]-5-hydroxy-4-(1,4,4-trimethyl-8-methylenedecahydroazulen-1-yl) tetrahydrofuro [2,3-b]furan-2(3H)-one, cheloviolene C (9), [1'ξ(1R*,3aS*,7aS*),4ξ]-4-[1′-( acetyloxymethyl )-2′-(4,4,7a-trimethyloctahydro-1H-inden-1-yl)prop-2′-enyl] dihydrofuran -2(3H)-one, cheloviolene D (10), methyl [3α,4α(1R*,3aR*,8aS*)]-5-oxo-4-(1,4,4-trimethyl-8-methylenedecahydroazulen-1-yl)tetrahydrofuran-3-acetate, cheloviolene E (11), methyl [3α,4α-(1R*,3aS*,7aS*)]-5-oxo-4-[1′-(4,4,7a-trimethyloctahydro-1H-inden-1-yl) ethenyl ]tetrahydrofuran-3-acetate, and cheloviolene F (12), [4ξ,5ξ(1R*,3R*,8aS*)]-4-( acetyloxymethyl )-5-(1,4,4-trimethyl-8-methylenedecahydroazulen-1-yl) tetrahydro-2H-pyran-2-one, by using spectroscopic methods; the structure (13) was deduced for cheloviolin, [1S-[1α,5α,6α,8R*(1aS*,3aS*,7aS*,7b-R*)]]-6-acetyloxy-8-(4,4,7a-trimethyldecahydrocylopropa[a] naphthalen-la-yl )-2,7-dioxabicyclo- [3.2.1]octan-3-one.
Collision-Induced Dissociations of Deprotonated Peptides. Dipeptides Containing Asn, Arg and Lys
Authors: Waugh RJ , Bowie JH , Gross ML
Published: October 2006

The presence and position of Asn, Arg and Lys residues in dipeptides may be determined from a consideration of the collisional activation mass spectra of the (M-H)- ions formed by fast atom bombardment. All spectra show the basic dipeptide cleavage, i.e. NH2CH(R1)CONHCH(R2)CO2- → NH2C(R1)CONHCH(R2)CO2H
→ NH2C(R1)=C=O + -NHCH(R2)CO2H. There are a number of fragmentations characteristic of a particular α side chain: for example, Arg loses HN=C=NH (42 u).