bluuebunny/crossref_metadata_2025 huggingface dataset:
Migrant women in male‐dominated sectors of the labour market: a research agenda
Authors: Raghuram Parvati
Published: October 2007

There is a growing literature on female labour migration, but much of this focuses on women who move to work in labour‐market sectors where a large proportion of workers are women. This paper argues that there has been much less study of women who migrate to work in male‐dominated sectors of the labour market, and explores the nature of this lacuna within research on female migration. It then highlights the increasing presence of women migrants in the ICT sector as one example of an area that has received little study. Finally, the paper explores some reasons why a study of female migrant's experiences in male‐dominated sectors of the labour market is important, and what it can add to existing research on female migration more generally. In particular, it urges us to view gender as it intersects and overlaps with other social divisions to produce complex landscapes of female mobility. Copyright © 2007 John Wiley & Sons, Ltd.
Fullerene derivatives encapsulated in carbon nanotubes
Authors: Plank W. , Kuzmany H. , Simon F. , Saito T. , Ohshima S. , Yumura M. , Iijima S. , Rotas G. , Pagona G. , Tagmatarchis N.
Published: October 2007

We report on the preparation and subsequent Raman analysis of carbon nanotube peapods, using the fullerene C60 and its heterofullerene derivative (C59N)2 as filling materials. The filling with (C59N)2 was done from liquid solution at room temperature and from the gas phase at elevated temperatures. The success of the encapsulation procedure is confirmed through the identification of fingerprint Raman modes and the conversion to double wall nanotubes through heating to 1250 °C. The 2D mode of double wall nanotubes made from (C59N)2 peapods is observed to be downshifted compared to the same mode in double wall nanotubes made from C60 peapods. We interpret this downshift as an evidence for the integration of the nitrogen into the lattice of the inner tube. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Principles of quantum computing
Authors: Mehring Michael
Published: October 2007

This contribution is intended to introduce the principles of quantum computing to those who always wanted to know about quantum computing but never dared to ask. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication of carbon nanotube‐based field‐effect transistors for studies of their memory effects
Authors: Zavodchikova M. Y. , Johansson A. , Rinkiö M. , Toppari J. J. , Nasibulin A. G. , Kauppinen E. I. , Törmä P.
Published: October 2007

Carbon nanotube‐based field‐effect transistors (CNTFETs) have been fabricated using nanometer thin dielectric material as the gate insulator film. The demonstrated fabrication technique is highly suitable for preparing devices with low contact resistances between the electrodes and the carbon nanotube, down to 14 kΩ. Electronic transport measurements of the fabricated devices have been conducted on more than 70 FETs. Hysteretic behavior in the transfer characteristics of some CNTFETs was observed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Validation of the PathFinder™ neurosurgical robot using a phantom
Authors: Eljamel M. S.
Published: October 2007

Background

Minimally invasive surgery was born out of recent advances in neuro‐imaging and stereotactic technology. As a result, the scale of neurosurgical procedures will soon be so small that it will not be within the ability of the most gifted and skilled neurosurgeons of today. Hence, neurosurgical robotics is the natural evolution in this field. The aim of this study was to evaluate the performance of a new robotic system in a neurosurgical phantom, comparing it to standard frame‐based and frameless technology of today.

Methods

In total, 19 different targets were approached by two standard stereotactic frames, the Stealth Station frameless system and the robot. The CRW and the ZD stereotactic frames were used. The frameless system was the Stealth Station image guidance system. The phantom used was a replica of the human skull fitted with 10 surface and nine deep targets.

Results

The robotic system outperformed both frame‐based and frameless systems in all experiments in this study. The application accuracies were: robot, 0.5 mm; stereotactic frames, 0.98 mm; and frameless system, 1.96 mm.

Conclusions

The robotic system was as accurate as the stereotactic frame, but without technical restrictions and cumbersome manual adjustments. Furthermore, the robotic system had near‐absolute geometric accuracy, was reliable to perform the same procedure over and over without tiresomeness, variation or boredom, and would be impervious to biohazards and hostile environments. Copyright © 2007 John Wiley & Sons, Ltd.
Repeated confidence intervals for adaptive group sequential trials
Authors: Mehta Cyrus R. , Bauer Peter , Posch Martin , Brannath Werner
Published: October 2007

This paper proposes a method for computing conservative confidence intervals for a group sequential test in which an adaptive design change is made one or more times over the course of the trial. The key idea, due to Müller and Schäfer (Biometrics2001;57:886–891), is that by preserving the null conditional rejection probability of the remainder of the trial at the time of each adaptive change, the overall type I error rate, taken unconditionally over all possible design modifications, is also preserved. We show how this principle may be extended to construct one‐sided confidence intervals by applying the idea to a sequence of dual tests derived from the repeated confidence intervals (RCIs) proposed by Jennison and Turnbull (J. Roy. Statist. Soc. B1989;51:301–361). These adaptive RCIs, such as their classical counterparts, have the advantage that they preserve the desired coverage probability even if the pre‐specified stopping rule is over‐ruled. The statistical methodology is explored by simulations and is illustrated by an application to a clinical trial of deep brain stimulation for Parkinson's disease. Copyright © 2007 John Wiley & Sons, Ltd.
Synthetic and Structural Studies of Lead and Bismuth Organohalides Bearing a β‐Diketiminato Ligand
Authors: Pineda Leslie W. , Jancik Vojtech , Nembenna Sharanappa , Roesky Herbert W.
Published: October 2007

Two novel organohalides of lead and bismuth supported by a ß‐diketiminato ligand are reported. Salt elimination reactions of the β‐diketiminatolithium salt and the corresponding lead and bismuth halides led to the isolation of lead [{HC(CMeNAr)2}PbBr] (2; Ar = 2,6‐iPr2C6H3) and bismuth [{HC(Et2NCH2CH2NCMe)2}BiCl2] (4), respectively. These new compounds have been characterized by spectrometric and elemental analyses, and the solid‐state structures have been determined by single‐crystal X‐ray structural analysis.
3,5‐Dimethyl‐4‐amino‐1,2,4‐triazole (Dat) as a Tridentate Ligand in the Polymeric Cations of [Ag3(Dat)2](NO3)3
Authors: Nockemann Peter , Meyer Gerd
Published: October 2007

Colourless single crystals of [Ag3(Dat)2](NO3)3 were obtained from a reaction of silver(I) nitrate and 3,5‐dimethyl‐4‐amino‐1,2,4‐triazole (Dat). In the crystal structure (orthorhombic, Fdd2, Z = 8, a = 1100.1(2), b = 3500.3(2), c = 1015.4(3) pm, R1 = 0.0434) there are two crystallographically non‐equivalent silver sites in a one (Ag1) to two ratio (Ag2). Both resemble linear N–Ag–N coordination although angles are 163° and 144°, respectively. Each Dat ligand coordinates with the two ring nitrogen atoms at 216 to 219 pm and with one amino‐nitrogen atom at 229 pm. According to the composition [Ag3(Dat)2]3+ = [(Dat)Ag3/2]3+, a polymeric structure is built with all Ag+ ions bridging.
Synthesis and Structures of New Copper‐Indium Thiolate Cluster Complexes
Authors: Adams Richard D. , Captain Burjor , Zhang Qian‐Feng
Published: October 2007

Two new copper indium thiolate complexes were obtained from the reactions of InCl3 and HSnBu with a combination of [Cu(NCMe)4][PF6] and 1,2‐bis(diphenylphosphino)ethane (dppe). In a mixture of methanol and MeCN solvent the complex [In2SnBu2(μ‐SnBu)2Cu2(μ‐dppe)2] (3) was formed. When this reaction was performed in a mixture of MeOH and CH2Cl2 solvent, a higher nuclearity species, [Cu(dppe)2][In4Cl4(μ‐SnBu)12Cu4(μ4‐Cl)] (4) was formed. The monoanion in 4 consists of a central tetrahedral chloride ion coordinated to four copper atoms. The copper atoms are linked to four outer InCl groups by three bridging butylthiolato ligands. Overall, this ion has approximate T‐symmetry and is chiral.
Molybdocene‐based Compounds containing Mo‐Sb and Mo‐Sn Bonds
Authors: Knispel Christina , Limberg Christian , Zimmer Lars , Ziemer Burkhard
Published: October 2007

With the background of the interesting reactivities and novel compounds revealed by investigations concerning the system [RCp2MoH2] and Bi(OtBu)3, analogous reactions of [MeCp2MoH2] with Sb(OtBu)3, SbCl3, SnCl2 and SnCl4 were examined. After treatment of [MeCp2MoH2] with Sb(OtBu)3, the product [MeCp2Mo(Sb(OtBu)2)2] (1), was identified spectroscopically, while the reaction with SbCl3 led to [MeCp2Mo(SbCl2)2] (2) in pure crystalline form so that an X‐ray crystal structure investigation could be performed revealing secondary interactions between the SbCl2 ligands. Treatment of [MeCp2MoH2] with SnCl2 and SnCl4 led to the compounds [MeCp2Mo(H)SnCl2(H)MoMeCp2] (3) and [MeCp2Mo(SnCl3)2] (4), respectively, whose crystal structures could be determined. The solid state structure of 3 served as the basis for a DFT geometry optimisation that, in turn, allowed for an analysis of the electronic structure of this compound. It turned out that the Mo–Sn bonds are polarised towards Mo so that a formal oxidation state of +IV can be assigned to the Sn atom. Facile formation of 4 was in so far surprising as the related reaction of [Cp2MoH2] with SnCl4 stops after the substitution of the first hydride ligand by a SnCl3 unit. Methylation of the Cp rings thus has a pronounced influence on the reactivity.
[{(C7H7LiO)6(thf)2(μ‐diglyme‐κO,κO′)}Li2O]: a μ6‐O2– Ion Encapsulating Aryllithium Compound
Authors: Strohmann Carsten , Gessner Viktoria H.
Published: October 2007

The oxygen‐incorporating compound [{(C7H7LiO)6(thf)(μ‐diglyme‐κO,κO′)}]Li2O (1) was obtained by lithiation of 2‐bromomethoxybenzene with n‐butyllithium in n‐pentane, thf and diglyme. 1 ranks among the rare species of μ6‐O2– ions encapsulating organolithium compounds. At the centre of this mixed aggregate is an octahedral Li6O‐unit, which is additionally capped by lithium atoms at two facing Li3 triangles.
A Stable η2‐Bonded Diazoalkane Complex
Authors: Schaub Thomas , Radius Udo
Published: October 2007

The synthesis and structural characterization of the new complexes [Ni(iPr2Im)2(η2‐C,C‐Me2C=CHCOMe)] (2), [Ni(iPr2Im)2(η2‐H2C=CH‐(4‐C5H4N)] (3) and [Ni(iPr2Im)2(η2‐N,N′‐N2CPh2)] (4) is reported. Complex 4 is remarkably stable under an inert gas atmosphere and does not undergo nitrogen loss under thermal or photochemical conditions.
[{Br2B(η5‐C5H4)}Mn(CO)3] – A versatile Precursor for Boron‐based Ligands
Authors: Braunschweig Holger , Bera Holger , Stellwag Sascha , Schwarz Sylvia , Hemberger Yasmin , Radacki Krzysztof
Published: October 2007

A range of potential boron‐based ligand precursors has been synthesized starting from [{Br2B(η5‐C5H4)}Mn(CO)3] (1) via salt elimination reactions. These comprise ligand precursors suitable for the preparation of i) ansa‐metallocenes such as [CymB(η1‐C5H5)2] (2), [CymB(1‐C9H7)2] (3a), and [CymB(3‐C9H7)2] (3b), ii) constrained geometry complexes such as [CymB(Br)N(H)tBu] (5) as well as iii) ansa‐diamido complexes such as [CymB{N(H)Ph}2] (4) and [CymB{N(H)tBu}2] (6) (Cym = cymantrenyl, C5H5 = cyclopentadienyl, C9H7 = indenyl). Furthermore, we present the hydrolysis of 1, leading to the three‐fold cymantrenyl‐substituted boroxine [{OB(η5‐C5H4)}Mn(CO)3]3 (7). All new compounds have been characterized by multinuclear NMR spectroscopic techniques and in the case of 1 and 7 by X‐ray diffraction analyses.
High‐Spin Ni3Fe2(CN)6 and Cu3Cr2(CN)6 Clusters Based on a Trigonal Bipyramidal Geometry
Authors: Bartlett Bart M. , Harris T. David , DeGroot Marty W. , Long Jeffrey R.
Published: October 2007

The synthesis and characterization of two new cyano‐bridged cluster compounds, [Tp2(cyclen)3NiII3FeIII2(CN)6](BF4)4 (1) and [(Me3tacn)5CuII3CrIII2(CN)6](ClO4)6 (2), are reported. The structure of each cluster is based upon a trigonal bipyramidal geometry, and ferromagnetic coupling between constituent metal ions is shown to give rise to S = 4 and S = $\rm ^{9}/_{2}$ ground states, respectively. A room‐temperature assembly reaction generates a purple form of compound 2, wherein two cyanide stretching frequencies in the infrared spectrum (νCN = 2094, 2156 cm−1) indicate partial isomerism of the cyanide bridging ligands. The X‐ray crystal structure confirms this isomerism via examination of the C and N thermal parameters. At −40 °C, a metastable green form of the compound is instead isolated, for which a single cyanide stretch at νCN = 2156 cm−1 is consistent with an unisomerized cluster. The temperature‐dependence of the magnetization under varying applied field reveals significant axial anisotropy in compound 1, with a significant axial zero‐field splitting while compound 2 shows no zero‐field splitting in either isolated form. In line with the observed anisotropy, AC magnetic susceptibility measurements performed on compound 1 reveal a frequency‐dependent out‐of‐phase signal suggestive of single‐molecule magnet behavior.
A Mixed‐valent Heterometallic [Mn4Co4] Complex from Reductive Rearrangement of a [Mn4] Single‐Molecule Magnet
Authors: Vallina Ana Tesouro , Lecren Lollita , Li Yang‐Guang , Roubeau Olivier , Clérac Rodolphe
Published: October 2007

The synthesis, crystal structure and magnetic properties of the mixed‐metal aggregate [Mn4Co4(hmp)6(pic)9(H2O)2(OH)](ClO4)3·xH2O·yCH3CN (3·xH2O·yCH3CN) are reported. This complex was prepared by the reaction of a [Mn4] single‐molecule magnet and a cobalt monomeric complex, [Co(pic)2(H2O)2]·2H2O (1). Complex 3 crystallizes in the triclinic ${\rm P}{\bar 1}$ space group and consists of a cationic [MnII4CoIII3CoII] octaheteronuclear complex that possesses a symmetric equilateral triangle‐based pyramid core with a cobalt main base and a manganese minor base.
Public Assistance and Job Search Behavior of the Rural Poor–Evidence from the Mississippi Delta
Authors: Fessehatzion Tekie , Fayissa Bichaka
Published: October 2007

This study explores whether prolonged welfare experience reduces the job search commitment of the unemployed. More specifically, an attempt is made to determine whether participation in a government assistance program induces the unemployed to prolong their job search activities, either through reduced search effort or by asking a higher reservation (acceptance) wage. The data were obtained from a semi-structured interview with 120 food stamp recipients participating in a pilot workfare project in Coahoma County, Mississippi. The interview questionnaire was designed to elicit the degree to which there was a relationship between welfare use and commitment to job search activities. The most important finding of the study was that in at least one economically depressed community, extended participation in a public assistance program did not appear to have a significant impact on the job search behavior of the unemployed. However, as important as this finding is, the small size of the sample and the uniqueness of the county (77 percent black) limit the applicability of the results to other rural communities across the nation. Therefore, there is a need to replicate and expand the study, utilizing a much larger sample representing a cross section of the counties in Mississippi and elsewhere in the United States.
Employment, Income and Economic Identity in the U.S. Virgin Islands
Authors: Domingo Jannette O.
Published: October 2007

The explosive tourism-led growth experienced by the U.S. Virgin Islands during the 1960s and early 1970s reflected the duality of the Virgin Islands’ socioeconomic identity. Although growth was dependent on the U.S. economy and U.S. policies, it also reaffirmed the links the Virgin Islands had developed with the Eastern Caribbean labor market in spite of their unique history as a Danish and then an American colony. Relatively large scale inflows of Eastern Caribbean labor caused both general and relative wage effects, compression of the wage and income structures, and redistribution of income away from labor. Increased labor market segmentation exacerbated the inherent ambivalence of the Virgin Islands’ Eastern Caribbean identity. The nature of the transformation of employment and income in the Virgin Islands undermined the benefits derived by the indigenous labor force and established the bases of subsequent socioeconomic conflict.
Role of Fibrin Glue as a Sealant to Esophageal Anastomosis in Cases of Congenital Esophageal Atresia with Tracheoesophageal Fistula
Authors: Upadhyaya Vijai D. , Gopal Saroj C. , Gangopadhyaya Ajay N. , Gupta Dinesh K. , Sharma Shiv , Upadyaya Ashsish , Kumar Vijayendra , Pandey Anand
Published: October 2007

Objective

The aim of this study was to characterize a successful approach for the management of infants with long‐gap esophageal atresia (EA) with tracheoesophageal fistula (TEF). The goal was to preserve the native esophagus and minimize the incidence of esophageal anastomotic leaks using fibrin glue as a sealant over the esophageal anastomosis.

Method

A total of 52 patients were evaluated in this study. Only patients in whom, gap between the two ends of the esophagus was ≥ 2 cm were selected during January 2005 to January 2007. Patients were divided in two groups on the basis of block randomization. Group A comprised the patients in whom fibrin sealant was used as reinforcement on a primary end‐to‐end esophageal anastomosis; in group B, fibrin glue was not used. The two groups were compared in terms of esophageal anastomotic leak (EL), postoperative esophageal stricture (ES), and mortality. The statistical analysis was done using Fisher’s exact test and the chi‐squared test.

Result

The number of anastomotic leaks in group A (glue group) was about one‐fifth that in group B (no glue group). The incidence of ES was almost twice as high in group B as in group A. The mortality rate was almost threefold higher in group B (no‐glue group). The higher incidence of EL and ES in group B compared to group A was statistically significant.

Conclusion

Thus, fibrin glue when used as an adjunct to esophageal anastomosis for primary repair of long‐gap EA with TEF appears safe in the clinical setting and may lower the chances of esophageal leak and anastomosis‐site strictures. Hence, it can diminish the mortality and morbidity of these patients.
Tocopherol Content and Fatty Acid Distribution of Peas (Pisum sativum L.)
Authors: Yoshida Hiromi , Tomiyama Yuka , Saiki Masayuki , Mizushina Yoshiyuki
Published: October 2007

The positional distribution of fatty acids (FA) of triacylglycerols (TAG) and major phospholipids (PL) prepared from four cultivars of peas (Pisum sativum L.) were investigated as well as their tocopherol contents. The lipids extracted from these peas were separated by thin‐layer chromatography (TLC) into seven fractions. The major lipid components were PL (52.2–61.3%) and TAG (31.2–40.3%), while the other components were also present in minor proportions (5.6–9.2%). γ‐Tocopherol was present in the highest concentration, and α‐ and δ‐tocopherols were very small amounts. The main PL components isolated from the four cultivars were phosphatidylcholine (42.3–49.2%), followed by phosphatidylinositol (23.3–25.2%) and then phosphatidylethanolamine (17.7–20.5%). Small but significant differences (P < 0.05) in FA distribution existed when different pea cultivars were determined. However, the principal characteristics of the FA distribution in the TAG and the three PL were evident among the four cultivars; unsaturated FA were predominantly located in the sn‐2 position, and saturated FA primary occupied the sn‐1 or sn‐3 position in the oils of the peas. These results suggest that the regional distribution of tocopherols and fatty acids in peas is not dependent on the climatic conditions and the soil characteristics of the cultivation areas during the growing season.
Global convergence toward traveling fronts in nonlinear parabolic systems with a gradient structure
Authors: Risler Emmanuel
Published: October 2007

We consider nonlinear parabolic systems of the form

u_{t} = −\mathrm{∇}V(u) + u_{xx}

, where

u \in \mathbb{R}^{n}

,

n⩾1

,

x \in \mathbb{R}

, and the potential
V
is coercive at infinity. For such systems, we prove a result of global convergence toward bistable fronts which states that invasion of a stable homogeneous equilibrium (a local minimum of the potential) necessarily occurs via a traveling front connecting to another (lower) equilibrium. This provides, for instance, a generalization of the global convergence result obtained by Fife and McLeod [P. Fife, J.B. McLeod, The approach of solutions of nonlinear diffusion equations to traveling front solutions, Arch. Rat. Mech. Anal. 65 (1977) 335–361] in the case

n = 1

. The proof is based purely on energy methods, it does not make use of comparison principles, which do not hold any more when

n > 1

.
Effects of kaolin particle film on Myzus persicae (Hemiptera: Aphididae) behaviour and performance
Authors: Barker J.E. , Holaschke M. , Fulton A. , Evans K.A. , Powell G.
Published: October 2007

The emergence of resistance mechanisms to, and revocation of, many insecticides used in the control of the polyphagus aphid pest, Myzus persicae (Sulzer), has increased the pressure to develop novel approaches for the control of the pest in many crops. Kaolin-based particle films provide a physical barrier against insect pests and show considerable potential for controlling M. persicae. We conducted a series of laboratory experiments to investigate the mode of action of kaolin against aphids. The material appeared to have no direct effect on M. persicae; spraying adult aphids with aqueous kaolin suspension had no significant impact on their subsequent survival or reproduction on untreated plants. Similarly, when aphids were placed on kaolin-treated host-plants (Brassica oleracea), their performance (survival, growth rate and reproduction) was not significantly different from aphids on untreated plants. However, when M. persicae were given a choice between kaolin-treated and untreated (or water solvent-treated) leaf areas, both adults and nymphs exhibited a significant preference for non-kaolin-treated host-plant material. Rejection of kaolin-treated plant material occurred very rapidly (within 20 min) and this behavioural effect may be related to the efficacy of kaolin in controlling aphids under field conditions.
“There is tragedy on both sides of the layoffs:” Privatization and the Urban Crisis in Baltimore
Authors: Berger Jane
Published: October 2007

By the 1960s, the urban crisis in the United States was well underway. Structural trans-formations in the postwar economy and accelerating deindustrialization contributed to high rates of unemployment in many cities in the nation's old industrial core. During the 1970s and 1980s, the urban crisis worsened. This article argues that the macroeconomic policies of Presidents Richard Nixon, Jimmy Carter, and Ronald Reagan fueled urban decline. Responding to the waning hegemony of the United States in the global economy as well as to a domestic corporate crisis of profitability, the presidents pursued macroeconomic agendas that prioritized the revitalization of American economic dominance. Macroeconomic policy decisions in combination with white-backlash pressures constrained the range of urban policies the presidents could pursue and often compelled privatization. The federal-level decisionmaking had devastating consequences in Baltimore, Maryland, the city discussed in this article. The macroeconomic and urban policies had racialized and gendered outcomes that plunged the city into the most acute phase of the urban crisis.
A Class Approach to Municipal Privatization: The Privatization of New York City's Central Park
Authors: Cooke Oliver
Published: October 2007

The privatization of New York City's Central Park in 1998 was among the most high-profile municipal privatizations in the US during the 1990s. Since then, the park's privatization has been cited as an exemplary model of privatization. This essay develops a unique class approach to municipal privatization and uses it to reconceptualize Central Park's privatization. In doing so, it argues that the park's privatization involves an important contradiction—one that regards its ostensible status as one of the nation's most famous and treasuredpublicgoods against its production as acapitalist commodity. This class approach to the park's privatization yields four insights. First, it underscores the limitations of the hegemonic cost-efficiency calculus that has long informed the municipal privatization discourse. Second, it raises important questions regarding the troublesome relationship between democratic principles and capitalist production relations. Third, it offers an alternative to a wage-led approach to privatization. Finally, and paradoxically, it provides a framework for theorizing “progressive” privatizations.
Comparison of nighttime nitric oxide 5.3 μm emissions in the thermosphere measured by MIPAS and SABER
Authors: Gardner J. L. , Funke B. , Mlynczak M. G. , López‐Puertas M. , Martin‐Torres F. J. , Russell J. M. , Miller S. M. , Sharma R. D. , Winick J. R.
Published: October 2007

A comparative study of nitric oxide (NO) 5.3 μm emissions in the thermosphere measured by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) spectrometer and the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) radiometer satellite instruments was conducted for nighttime data collected on 14 June 2003. The agreement between the data sets was very good, within ∼25% over the entire latitude range studied from −58° to + 4°. The MIPAS and SABER data were inverted to retrieve NO volume emission rates. Spectral fitting of the MIPAS data was used to determine the NO(v = 1) rotational and spin‐orbit temperatures, which were found to be in nonlocal thermodynamic equilibrium (non‐LTE) above 110 km. Near 110 km the rotational and spin‐orbit temperatures converged, indicating the onset of equilibrium in agreement with the results of non‐LTE modeling. Because of the onset of equilibrium the NO rotational and spin‐orbit temperatures can be used to estimate the kinetic temperature near 110 km. The results indicate that the atmospheric model NRLMSISE‐00 underestimates the kinetic temperature near 110 km for the locations investigated. The SABER instrument 5.3 μm band filter cuts off a significant fraction of the NO(Δv = 1) band, and therefore modeling of NO is necessary to predict the total band radiance. The needed correction factors were directly determined from the MIPAS data, providing validation of the modeled values used in SABER operational data processing. The correction factors were applied to the SABER data to calculate densities of NO(v = 1). A feasibility study was also conducted to investigate the use of NO 5.3 μm emission data to derive NO(v = 0) densities in the thermosphere.
Origin of the interhemispheric potential mismatch of merging cells for interplanetary magnetic field BY‐dominated periods
Authors: Watanabe Masakazu , Sofko George J. , Kabin Konstantin , Rankin Robert , Ridley Aaron J. , Clauer C. Robert , Gombosi Tamas I.
Published: October 2007

When the dawn‐to‐dusk component of the interplanetary magnetic field (IMF BY) is dominant, ionospheric convection exhibits a basic two‐cell pattern with significant dawn‐dusk and interhemispheric asymmetries. For IMF BY > 0 the duskside merging cell potential in the Northern Hemisphere is much higher than that in the Southern Hemisphere, and the dawnside merging cell potential in the Southern Hemisphere is much higher than that in the Northern Hemisphere. The situation is reversed for IMF BY < 0. This interhemispheric potential mismatch originates from reconnection of overdraped lobe field lines and closed flankside field lines. This type of north‐south asymmetric reconnection does not affect the merging cell potentials in the same hemisphere as the reconnection point, whereas in the opposite hemisphere, it diminishes the potential of the dawnside (or duskside) Dungey‐type merging cell. Thus the total dawnside (or duskside) merging cell potential in one hemisphere is smaller than that in the other hemisphere by the reconnection voltage associated with the asymmetric reconnection.
Examining the wintertime response to tropical convection over the Indian Ocean by modifying convective heating in a full atmospheric model
Authors: Barlow Mathew , Hoell Andrew , Colby Frank
Published: October 2007

The boreal winter response to tropical convection in the eastern Indian Ocean is investigated by increasing the mid‐level diabatic heating for that region in the NCAR Community Atmosphere Model, version 3.1. The response is quite similar to the analytic Gill solution to steady heating, with a pair of Rossby wave packets poleward and to the west of the heating, extending into mid‐latitudes, and a Kelvin response to the east of the heating. Changes to tropical convection in the eastern Indian Ocean are an important component of several important modes of atmospheric variability, including the Madden‐Julian Oscillation, some El Niño‐Southern Oscillation events, and the Indian Ocean Dipole. The simulated response has considerable similarities to observational aspects of these modes, both in terms of the Gill‐like circulation patterns and changes to precipitation over Southwest Asia, demonstrating the central importance of the Indian Ocean convection in determining the regional response.
Pāhoehoe flow cooling, discharge, and coverage rates from thermal image chronometry
Authors: Harris Andrew J. L. , Dehn Jonathan , James Mike R. , Hamilton Christopher , Herd Richard , Lodato Luigi , Steffke Andrea
Published: October 2007

Theoretically‐ and empirically‐derived cooling rates for active pāhoehoe lava flows show that surface cooling is controlled by conductive heat loss through a crust that is thickening with the square root of time. The model is based on a linear relationship that links log(time) with surface cooling. This predictable cooling behavior can be used assess the age of recently emplaced sheet flows from their surface temperatures. Using a single thermal image, or image mosaic, this allows quantification of the variation in areal coverage rates and lava discharge rates over 48 hour periods prior to image capture. For pāhoehoe sheet flow at Kīlauea (Hawai`i) this gives coverage rates of 1–5 m2/min at discharge rates of 0.01–0.05 m3/s, increasing to ∼40 m2/min at 0.4–0.5 m3/s. Our thermal chronometry approach represents a quick and easy method of tracking flow advance over a three‐day period using a single, thermal snap‐shot.
Impact of skeletal dissolution and secondary aragonite on trace element and isotopic climate proxies in Porites corals
Authors: Hendy E. J. , Gagan M. K. , Lough J. M. , McCulloch M. , deMenocal P. B.
Published: October 2007

Restricted zones of recent dissolution and secondary aragonite infilling were identified in a coral core collected in 1986 from a living massive Porites colony from the central Great Barrier Reef, Australia. Secondary aragonite needles, ≥20 μm long, cover skeletal surfaces deposited from 1972 to late 1974 and increase bulk density by 10%. Dissolution is observed above this zone, whereas older skeleton is pristine. We investigate the impact of both types of early marine diagenesis on skeletal geochemistry and coral paleoclimate reconstructions by comparison with similar records from eight contemporary Porites colonies collected at nearby reefs. Secondary aragonite overgrowth causes anomalies in skeletal density, Mg/Ca, Sr/Ca, U/Ca, δ18O, and δ13C. The secondary aragonite is consistently associated with a cool temperature anomaly for each of the sea surface temperature (SST) proxies (δ18O‐SST −1.6°C; Sr/Ca‐SST −1.7°C; Mg/Ca‐SST −1.9°C; U/Ca‐SST −2.8°C). Dissolution, through incongruent leaching, also causes cool SST artifacts but only for trace element ratios (Mg/Ca‐SST −1.2°C; Sr/Ca‐SST −1.2°C; U/Ca‐SST −2.1°C). The sequence of preference with respect to dissolution of coral skeleton in seawater is Mg > Ca > Sr > U. Rigorous screening of coral material for paleoclimate reconstructions is therefore necessary to detect both dissolution and the presence of secondary minerals. The excellent agreement between apparent SST anomalies generated by different modes of diagenesis means that replication of tracers within a single coral cannot be used to validate climate‐proxy interpretations. Poor replication of records between different coral colonies, however, provides a strong indication of nonclimatic artifacts such as dissolution and secondary aragonite.
Calculation of frequency-dependent hyperpolarizabilities using general coupled-cluster models
Authors: O’Neill Darragh P. , Kállay Mihály , Gauss Jürgen
Published: October 2007

By exploiting the similarities between response theory and analytic derivative theory, we present a scheme for calculating frequency-dependent hyperpolarizabilities at the coupled-cluster level within the framework for analytic third derivatives. This has been implemented for arbitrary levels of coupled-cluster theory up to the full-configuration-interaction limit. An investigation of some small molecules shows that the inclusion of triple excitations is essential for an accurate description of hyperpolarizabilities.
Molecular mechanics-valence bond method for planar conjugated hydrocarbon cations
Authors: Hall Katherine F. , Tokmachev Andrei M. , Bearpark Michael J. , Boggio-Pasqua Martial , Robb Michael A.
Published: October 2007

We present an extension of the molecular mechanics-valence bond (MMVB) hybrid method to study ground and excited states of planar conjugated hydrocarbon cations. Currently, accurate excited state calculations on these systems are limited to expensive ab initio studies of smaller systems: up to 15 active electrons in 16 π orbitals with complete active space self-consistent field (CASSCF) theory using high symmetry. The new MMVB extension provides a faster, cheaper treatment to investigate larger cation systems with more than 24 active orbitals. Extension requires both new matrix elements and new parameters: In this paper we present both, for the limited planar case. The scheme is tested for the planar radical cations of benzene, naphthalene, anthracene, and phenanthrene. Calculated MMVB relative energies are in good agreement with CASSCF results for equilibrium geometries on the ground and first excited states, and conical intersections.
Macroscopic descriptions of rarefied gases from the elimination of fast variables
Authors: Dellar Paul J.
Published: October 2007

The Boltzmann equation describing a dilute monatomic gas is equivalent to an infinite hierarchy of evolution equations for successive moments of the distribution function. The five moments giving the macroscopic mass, momentum, and energy densities are unaffected by collisions between atoms, while all other moments naturally evolve on a fast collisional time scale. We show that the macroscopic equations of Chen, Rao, and Spiegel [Phys. Lett. A 271, 87 (2000)], like the familiar Navier-Stokes-Fourier equations, emerge from using a systematic procedure to eliminate the higher moments, leaving closed evolution equations for the five moments unaffected by collisions. The two equation sets differ through their treatment of contributions from the temperature to the momentum and energy fluxes. Using moment equations offers a definitive treatment of the Prandtl number problem using model collision operators, greatly reduces the labor of deriving equations for different collision operators, and clarifies the role of solvability conditions applied to the distribution function. The original Chen-Rao-Spiegel approach offers greatly improved agreement with experiments for the phase speed of ultrasound, but when corrected to match the Navier-Stokes-Fourier equations at low frequencies, it then underestimates the phase speed at high frequencies. Our introduction of a translational temperature, as in the kinetic theory of polyatomic gases, motivates a distinction in the energy flux between advection of internal energy and the work done by the pressure. Exploiting this distinction yields macroscopic equations that offer further improvement in agreement with experimental data, and arise more naturally as an approximation to the infinite hierarchy of evolution equations for moments.
Topological building blocks of hydrogen bond network in water
Authors: Matsumoto M. , Baba A. , Ohmine I.
Published: October 2007

Basic three-dimensional units of the network, called fragments, are introduced to characterize the hydrogen bond (HB) network structure of water. Topological differences among normal liquid water, water at low temperature, and water under high pressure are elucidated by their fragment statistics. Water at low temperature has almost defect-free network and is filled with stable fragments with small distortion. It is found that there exists a certain way on how fragments mutually aggregate. Well-formed aggregates heterogeneously constitute very stable network structures. HB network rearrangements occur scarcely inside these aggregated domains but take place in their surface areas. The heterogeneity of HB structure and rearrangement in water is thus explained in terms of the fragment structure and its rearrangements. The fragment analysis thus elucidates the intermediate-range order in water HB network.
Electronic structure of interfaces between copper-hexadecafluoro-phthalocyanine and 2,5-bis(4-biphenylyl) bithiophene
Authors: Gao Yongli , Ding Huanjun , Wang Haibo , Yan Donghang
Published: October 2007

The interfaces formed between copper-hexadecafluoro-phthalocyanine (F16CuPc) and 2,5-bis(4-biphenylyl) bithiophene (BP2T) were examined using photoemission and inverse photoemission spectroscopy. It is observed that in F16CuPc∕BP2T the heterojunction is characterized by band bending in both materials, while in BP2T∕F16CuPc the band bending is confined in BP2T only. The combination of the band bending and finite Debye lengths provides an explanation to the observed ambipolar behavior of the organic thin film transistors based on such heterojunctions.
Ga
As
N
∕
In
As
N
superlattice based multijunction thermophotovoltaic devices
Authors: Bhusal L. , Freundlich A.
Published: October 2007

Quantitative modeling of the performance of a single and multijunction p(InGaAs)-i(superlattice)-n(InGaAs) device lattice matched to InP utilizing a GaAsN∕InAsN superlattice structure is performed, and the results are compared quantitatively with the bulk metamorphic InGaAs counterpart devices. Optimized band gaps of the subcells of multijunction device are estimated by finding the optimal current to provide the maximum power through the series-connected double, triple, and quadruple junction cells for 1350K blackbody radiation as an incident flux. The output power-density of the four junction superlattice device is shown to be ∼1.8W∕cm2, for the fixed 0.74eV first cell band gap. Lattice matching to InP substrate and the availability of various band gaps from the GaAsN∕InAsN structure are emphasized for the use in multijunction thermophotovoltaic device producing higher output power densities in comparison to the bulk InGaAs based devices.
Study of the interfacial regions in Fe∕Cr multilayers
Authors: Alayo W. , Tafur Miguel , Xing Y. T. , Baggio-Saitovitch E. , Nascimento V. P. , Alvarenga A. D.
Published: October 2007

The magnetism at the interfacial regions of the [Fe(50Å)∕Cr(27Å)]20 antiferromagnetic coupled multilayer was studied using the x-ray magnetic circular dichroism (XMCD) technique. Two experimental approaches were used to reach the interface regions. In the first one, multilayers of the same type, deposited with the Cr capping layer with different thicknesses of 30, 20, 10, and 5Å, were analyzed and we obtained a magnetic depth profile without removing the layers. In the second approach, the layers of the sample were thinned by several in situ sputtering cycles with Ar+ ions, followed by XMCD analysis. We found a strong reduction of the Fe spin magnetic moments in the sputtered sample, which was caused by the erosion of the layers. On the contrary the noneroded samples kept the Fe bulk moment values. The observation of Cr XMCD signal evidenced an induced moment on Cr antiparallel to the Fe moments.
Solution-processed organic tandem solar cells with embedded optical spacers
Authors: Hadipour Afshin , de Boer Bert , Blom Paul W. M.
Published: October 2007

We demonstrate a solution-processed polymer tandem solar cell in which the two photoactive single cells are separated by an optical spacer. The use of an optical spacer allows for an independent optimization of both the electronic and optical properties of the tandem cell. The optical transmission window of the bottom cell is optimized to match the optical absorption of the top cell by varying the layer thickness of the optical spacer. The two bulk heterojunction subcells have complementary absorption maxima at λmax∼850nm for the top cell and λmax∼550nm for the bottom cell. The subcells are electronically coupled in series or in parallel using four electrical contacts. The series configuration leads to an open-circuit voltage of >1V, which is equal to the sum of both subcells. The parallel configuration leads to a high short-circuit current of 92A∕m2, which is equal to the sum of both subcells. The parallel configuration results in a much higher efficiency compared to the series configuration.
La Mn O 3 effects on the ferroelectric and magnetic properties of chemical solution deposited BiFeO3 thin films
Authors: Habouti S. , Solterbeck C-H. , Es-Souni M.
Published: October 2007

Thin films of the BiFeO3–LaMnO3 solid solution were processed on (111)-Pt∕Ti∕SiO2∕Si substrates via spin coating. Microstructure, and leakage current, ferroelectric and magnetic properties are reported. It is shown that the addition of 5mol% LaMnO3 substantially improves the properties. Leakage currents that are several orders of magnitude lower than those of pure BiFeO3 were obtained. The leakage currents follow the Poole-Frenkel mechanism, and a trap depth of 0.94eV was obtained. The addition of LaMnO3 resulted in saturated polarization hysteresis loops with a high remnant polarization 2Pr of 88μC∕cm2. Finally, LaMnO3 also leads to higher coercive fields but smaller saturation magnetization.
13
GHz
direct modulation of terahertz quantum cascade lasers
Authors: Barbieri Stefano , Maineult Wilfried , Dhillon Sukhdeep S. , Sirtori Carlo , Alton Jesse , Breuil Nicolas , Beere Harvey E. , Ritchie David A.
Published: October 2007

By directly modulating the bias voltage of a double-metal waveguide, 2.8THz quantum cascade laser, we observe the appearance of multiple gigahertz sidebands in the emission spectrum, with a spacing that can be continuously tuned up to 13GHz. By using an upconversion technique, the terahertz spectrum is shifted at 1.57μm, and displayed on an optical spectrum analyzer. A marked increase in the number of sidebands is observed when the modulation frequency approaches the round-trip frequency (∼12.3GHz). The laser packaging high frequency response has been measured using a microwave rectification technique, and is limited by the bond-wire parasitic inductance.
Liquid crystal polymer composite films for reconfigurable photomasking applications
Authors: Fox Anna E. , Fontecchio Adam K.
Published: October 2007

We show proof of concept of a real-time reconfigurable photomask fabricated from holographically formed polymer-dispersed liquid crystal (H-PDLC) reflection gratings on etched indium tin oxide patterned electrodes. H-PDLC films were formed using a thiolene based polymer to have a reflection wavelength that modulates 440nm, the peak sensitivity wavelength of Shipley 1800 series positive photoresist. A working prototype of this adaptable photomask device is shown by comparing patterns formed using the H-PDLC mask and similar patterns formed using a static contact photomask showing that H-PDLC films have the ability to modulate 440nm light and control the exposure dose of photoresist.
Room temperature, continuous-wave operation of quantum cascade lasers with single phonon resonance-continuum depopulation structures grown by metal organic vapor-phase epitaxy
Authors: Fujita K. , Furuta S. , Sugiyama A. , Ochiai T. , Edamura T. , Akikusa N. , Yamanishi M. , Kan H.
Published: October 2007

We propose a new quantum-cascade laser structure with single phonon resonance-continuum depopulation and demonstrate room temperature, continuous-wave operation of the proposed 7.9μm quantum-cascade laser. The laser grown by metal organic vapor-phase epitaxy emits a cw output power of 36mW at 30°C, exhibiting a threshold current density of 2.23kA∕cm2. The cw operation is reported for higher temperatures up to slightly above 60°C. The proposed structure may lead to a successful commercial mass production of the lasers.
Z-ring force and cell shape during division in rod-like bacteria
Authors: Lan Ganhui , Wolgemuth Charles W. , Sun Sean X.
Published: October 2007

The life cycle of bacterial cells consists of repeated elongation, septum formation, and division. Before septum formation, a division ring called the Z-ring, which is made of a filamentous tubulin analog, FtsZ, is seen at the mid cell. Together with several other proteins, FtsZ is essential for cell division. Visualization of strains with GFP-labeled FtsZ shows that the Z-ring contracts before septum formation and pinches the cell into two equal halves. Thus, the Z-ring has been postulated to act as a force generator, although the magnitude of the contraction force is unknown. In this article, we develop a mathematical model to describe the process of growth and Z-ring contraction in rod-like bacteria. The elasticity and growth of the cell wall is incorporated in the model to predict the contraction speed, the cell shape, and the contraction force. With reasonable parameters, the model shows that a small force from the Z-ring (8 pN in
Escherichia coli
) is sufficient to accomplish division.
Coevolution of languages and genes on the island of Sumba, eastern Indonesia
Authors: Lansing J. Stephen , Cox Murray P. , Downey Sean S. , Gabler Brandon M. , Hallmark Brian , Karafet Tatiana M. , Norquest Peter , Schoenfelder John W. , Sudoyo Herawati , Watkins Joseph C. , Hammer Michael F.
Published: October 2007

Numerous studies indicate strong associations between languages and genes among human populations at the global scale, but all broader scale genetic and linguistic patterns must arise from processes originating at the community level. We examine linguistic and genetic variation in a contact zone on the eastern Indonesian island of Sumba, where Neolithic Austronesian farming communities settled and began interacting with aboriginal foraging societies ≈3,500 years ago. Phylogenetic reconstruction based on a 200-word Swadesh list sampled from 29 localities supports the hypothesis that Sumbanese languages derive from a single ancestral Austronesian language. However, the proportion of cognates (words with a common origin) traceable to Proto-Austronesian (PAn) varies among language subgroups distributed across the island. Interestingly, a positive correlation was found between the percentage of Y chromosome lineages that derive from Austronesian (as opposed to aboriginal) ancestors and the retention of PAn cognates. We also find a striking correlation between the percentage of PAn cognates and geographic distance from the site where many Sumbanese believe their ancestors arrived on the island. These language–gene–geography correlations, unprecedented at such a fine scale, imply that historical patterns of social interaction between expanding farmers and resident hunter-gatherers largely explain community-level language evolution on Sumba. We propose a model to explain linguistic and demographic coevolution at fine spatial and temporal scales.