bluuebunny/crossref_metadata_2025 huggingface dataset:
Made in America? the us auto industry, 1955‐95
Authors: Eden Lorraine , Molot Maureen Appel
Published: April 2007

This paper examines the production and political responses of the Big Three auto assemblers to the penetration of the North American market by Japanese auto assemblers over the 1955‐95 period, using the technological competition model to analyze three successive challenges faced by the Big Three: import competition (1955‐73), surplus capacity (1973‐83), and transplant production (1983‐95). We argue that the US auto makers first responded with intensification strategies and then by rationalizing production. These production strategies, together with lobbying for favorable US government policies, were unsuccessful in stemming import penetration. It was only after the Japanese firms began onshore production that the Big Three understood the competitive challenge‐the need to shift from mass to lean production‐and began to transform their auto operations.
Trends in international business thought and literature: One country, two currencies? Hong Kong's exchange‐rate regime after 1997
Authors: Wu Friedrich , Wong Jill
Published: April 2007

A key factor in assessing the future of the Hong Kong dollar is whether China would, after 1997, take the drastic step of abolishing the Hong Kong dollar in favor of the Renminbi (RMB) as legal tender. While this possibility should not be discounted, our view is that a merger of the two currencies would only occur in the distant future when the RMB becomes fully convertible. This study argues that the status quo of the HK$‐US$ link would be preserved at least until the turn of the century. A combination of factors, including the overriding need to maintain confidence and stability in Hong Kong, which is crucial for a smooth transition of sovereignty; the weak relationship between either imported or domestic‐generated inflation and the exchange rate link; and the misconception that Hong Kong's export competitiveness has been undermined by an overvalued Hong Kong dollar would help to support the argument that other alternative regimes for the Hong Kong dollar exchange rate would not be feasible in the short run. These alternative regimes include changing to a floating rate
Indian ocean rim trade bloc: Prospects and problems
Authors: Jain Subhash C. , Ghauri Pervez N.
Published: April 2007

This article advances the view that regional integration among ten nations along the Indian Ocean rim will have positive economic and political consequences for all the members. Emergence of this geographically large area with one‐fourth of the human population will be good for financial markets and the global economy as well. Planned regional arrangements will offer major benefits to outsiders, for example, Gulf countries, by stimulating growth and enhancing market forces. Traditional enmity between India and Pakistan, however, and the economic and political adjustments that South Africa is undergoing after the first free election may prevent cooperation in the region, not to mention the fact that the area has deep economic problems with mass poverty and low per capita incomes. Problems aside, there are hopeful signs, both economic and political, that encourage the Indian Ocean rim nations to seriously consider establishing a regional trade bloc. For example, a substantial middle class is emerging in the area. Industrialization is slowly progressing, challenging the dominance of the agricultural sector. India, however, will have to take the initiative in the matter. The size of her economy and her pre‐eminence as a regional political force equip India to play the key role in the establishment of a regional agreement in the area.
Us foreign direct investment in India: Emerging trends in MNC entry strategies
Authors: Chandrasekaran Aruna , Ryans John K.
Published: April 2007

India, along with China, is one of the key emerging markets in the region that has attracted multinational corporate interest. This has been enhanced by recent economic reforms and enormous market potential. After briefly tracing the political precipitants of the economic reforms, this article reviews the new FDI rules and the opportunities and challenges that this new investment climate presents the US investor. Finally, the FDIs of 30 US MNCs are classified according to the entry strategies being employed and some rationale is provided on the primary entry modes of choice.
Perceptions of Indian business organizations toward formal marketing research
Authors: Panigrahi Bhagaban , Misra Ranjita , Calcich Stephen E.
Published: April 2007

The results reported in this article are based on a mail survey of 219 firms in India. The major purpose of the study is to examine the marketing research experiences of Indian business firms and their perceptions about conducting formal marketing research. Results indicate that 45 percent of Indian firms have had some experience with formal marketing research and have positive perceptions concerning marketing research as an important decision making tool. Size and type of firm were found to influence whether formal marketing research is conducted. Research methodologies used in India are presented along with problems encountered by these practitioners.
Us consumer product marketing in Saudi Arabia: Comparative perceptions
Authors: Al‐Saihati Fawzia Ali , Krishnamoorthy Meenakshi S.
Published: April 2007

The period between 1970 and 1990 has seen a steady decline of the market share of US products in Saudi Arabia. This article deals with the differing perceptions of US exporters and Saudi importers regarding factors that might have contributed to this decline. These factors include the marketing environment, the product, the price, the distribution, US business practices, advertising, trade policies and the market situation in Saudi Arabia, and the role played by the US government. An analysis of these factors has led to a series of recommendations to respective governments and businesses.
Reversible Transamination of Alanine with Pyridoxal (Vitamin B6) in the Presence of the UO22+ Ion: Synthesis and X‐ray Characterization of [(UO2PmHpyr)3(μ3‐O)]Cl·3H2O (PmHpyr = Pyridoxaminylpiruvate Anion)
Authors: Back Davi Fernando , Manzoni de Oliveira Gelson , Schulz Lang Ernesto
Published: April 2007

Pyridoxal hydrochloride and alanine react in water with UO2(NO3)2·6H2O giving [(UO2PmHpyr)3(μ3‐O)]Cl·3H2O (1), a trinuclear chelate of uranium(VI). The ligand PmHpyr− (pyridoxaminylpiruvate anion) results from the transamination of alanine with pyridoxal in the presence of the uranyl cation. The coordination polyhedron of the individual uranium atoms can be described as pentagonal bipyramides. In the structure of 1 the cations [(UO2PmHpyr)3(μ3‐O)]+ interact reciprocally achieving a supramolecular assembling of [(UO2PmHpyr)3(μ3‐O)] cores indirectly linked to six surrounding ones through N+–H···Cl− interactions. Each chloride ion is bonded to three [(UO2PmHpyr)3(μ3‐O)]+ moieties (and reverse), reaching both ions a planar coordination number 6. There are evidences that pyridoxal or pyridoxal 5‐phosphate in the presence of UO22+ afford the transamination also of other amino acids used by the cells in protein biosynthesis. This extensive reaction in the blood plasma could represent a probable mechanism of uranium intoxication, e.g. by deactivation of the vitamin B6 derivatives pyridoxal or pyridoxamine through reaction with the corresponding α‐keto acid and further chelation of the uranyl cation.
Dinukleare Titankomplexe des Thiacalix[4]arens
Authors: Zeller Jürgen , Treptow Jens , Radius Udo
Published: April 2007

Dinuclear Titanium Complexes of Thiacalix[4]arene

The reaction of [TiCl4(THF)2] with thiacalix[4]arene (H4TCA) affords almost insoluble [TCA{TiCl2(THF)}2] (1). Single crystal X‐ray analysis reveals that the thiacalix[4]arene ligand coordinates at least in a part of the reaction product in an 1,2‐alternate cone conformation and that the metal atoms are therefore arranged in opposite directions with respect to a plane through the sulfur atoms of the ligand (anti‐configuration). The use of [Ti2(acac)4(μ‐O)2] as starting material causes the formation of the soluble homodinuclear complex [TCA{Ti(acac)}2(μ–O)] (2) in good yields, in which the thiacalix[4]arene ligand adopts a cone conformation and the metal atoms are thus arranged in syn‐configuration. Reaction of 2 with 8‐hydroxyquinoline leads to substitution of the acetylacetonato ligands of 2 under formation of crystallographically characterized [TCA{Ti(OC9H5N)}2(μ–O)] (3).
Synthesis and Characterization of Triphenylphosphinesilver(I) Sulfanylcarboxylates of Types [(AgPPh3)(HL)] and [Ag(PPh3)3(HL)]
Authors: Barreiro Elena , Casas José S. , Couce María D. , Sánchez Agustín , Sordo José , Varela José M. , Vázquez‐López Ezequiel M.
Published: April 2007

Compounds of types [(AgPPh3)(HL)] and [Ag(PPh3)3(HL)] {H2L = H2xspa: x = p (3‐phenyl‐), t [3‐(2‐thienyl)‐], f [3‐(2‐furyl)‐]; spa = 2‐sulfanylpropenoato} were synthesized and characterized by IR, 1H, 13C and 31P NMR spectroscopy and FAB mass spectrometry. The structures of [(AgPPh3)(Htspa)] (2) and [Ag(PPh3)3(Hpspa)] (4) were determined by X‐ray diffractometry. Complex 2 has a supramolecular structure based on hydrogen bonding between dinuclear units which can be seen as formed by Ag(PPh3)(Htspa) monomers connected by Ag‐S bonds, the metal atom in each monomer being O,S‐chelated. Complex 4 has a mononuclear structure with Ag‐S and Ag‐P bonds and an intramolecular hydrogen bond.
Jahn‐Teller‐Ordnung in der Schichtstruktur von Li[MnF4]·H2O
Authors: Massa Werner
Published: April 2007

Jahn‐Teller Ordering in the Layer Structure of Li[MnF4]·H2O

From hydrofluoric acid the new fluoromanganate(III) Li[MnF4]·H2O could be crystallized. Its structure was determined by X‐ray diffraction: orthorhombic, space group Pnma, Z = 4, a = 5.355(1), b = 12.358(3), c = 5.381(1) Å, R = 0.044. The structure is built by strongly bent quadratic anionic layers [MnF4]− connected by chains of Li+ and H2O. Owing to the Jahn‐Teller effect, antiferrodistortive ordering of strongly elongated octahedra is observed. The strucure is compared with that of waterfree Li[MnF4].
Syntheses of N‐(Diphenylphosphanyl)‐2‐pyridylmethylamine and Its Use as a Ligand in Magnesium and Zinc Complexes
Authors: Olbert Dirk , Kalisch Alexander , Herzer Nicole , Görls Helmar , Mayer Peter , Yu Lian , Reiher Markus , Westerhausen Matthias
Published: April 2007

The metathesis reaction of lithium 2‐pyridylmethylamide with chloroalkanes and phosphanes yields N‐ and C‐substitution products depending on the electrophile. Thus, C‐alkylated 1‐amino‐1‐(2‐pyridyl)‐2,2‐dimethylpropane (1) and 1‐amino‐1‐(2‐pyridyl)‐2‐phenylethane (2) and N‐substituted N‐benzyl‐(2‐pyridylmethyl)amine (3) and N‐(diphenylphosphanyl)‐2‐pyridylmethylamine (4) are obtained. In [1·LiCl]2, molecule 1 binds to the lithium atom in a bidentate fashion. C‐ and N‐ substituted 2‐pyridylmethylamines are compared with quantum chemical methods. Lithiation of 4 and subsequent reaction with cloro‐diphenylphosphane yields N,N‐bis(diphenylphosphanyl)‐2‐pyridylmethylamine (5) with a planar amine nitrogen atom. Metallation of 4 with dibutylmagnesium leads to the formation of colorless (tetrahydrofuran)magnesium bis[N‐(diphenylphosphanyl)‐2‐pyridylmethylamide] (6) with a penta‐coordinate alkaline earth metal atom in a trigonal bipyramidal environment. In contrast to this observation, the reaction of 4 with dimethylzinc yields colorless methylzinc bis[N‐(diphenylphosphanyl)‐2‐pyridylmethylamide] (7). Zincation of 1 gives dimeric methylzinc 1‐(2‐pyridyl)‐2,2‐dimethyl‐1‐propylamide (8). In these zinc complexes the metal and amide nitrogen atoms are in distorted tetrahedral environments.
Dimeric Phosphinoboranes [R′(Hal)B‐PHR]2 and some of their Reactions
Authors: Jetzfellner Ralf , Nöth Heinrich , Paine Robert T.
Published: April 2007

Reactions of organylboron halides RBX2 (R = tBu, iPr, Et, Me; X = Cl, Br) with lithium organylphosphides LiPHR′ (R′= mes, Ph, tBu) in a 1:1 ratio lead to the corresponding 1,3,2,4‐diphospha‐dibora‐cyclobutanes [R′(H)P‐B(Hal)R]2. Further substitution to 2,4‐diphosphino derivatives has only be achieved for [tBu(H)P‐B(tBu)PHtBu]2 (12). Its exocyclic PHtBu groups can be metallated by LiPHtBu, but it is more convenient to use the 1 : 3 reaction of tBuBCl2 with LiPHtBu for the preparation of [tBu(H)P‐B(tBu)PLitBu]2 (16), which was isolated as a diethyl ether solvate. Compound 12 on irradiation with a mercury vapour lamp splits off tBuPH2 and generates the bicyclic tBuP[BtBu‐PHtBu]2 (17). The new compounds have been characterized by NMR and Mass spectral data. The tBu groups of compound [Br(tBu)B‐PHtBu]2 (7), are present in an all‐trans‐configuration. Its B2P2 ring is planar.
What Every New Manager Needs to Know: Making a Successful Transition to Management
Authors: Davis Rebecca J.
Published: April 2007

What Every New Manager Needs to Know: Making a Successful Transition to Management, Gerard H. (Gus) Gaynor, 2004, 256 pages, $17.95 softcover
Unusual presentation of temporal bone involvement in Churg–Strauss syndrome
Authors: Martinez Del Pero M , Moffat D , Sudhoff H
Published: April 2007

Objective:

To present a case of a 60-year-old male with a history of sudden onset sensorineural hearing loss due to Churg–Strauss syndrome.

Case report:

The patient had a 20-year history of asthma and recurrent right otitis media and a nasal polypectomy four years prior to presenting with ear symptoms. Ear, nose and throat involvement is common in Churg–Strauss syndrome, usually manifesting as allergic rhinitis and chronic rhinosinusitis with or without polyps.

Conclusions:

Otolaryngologists play an important role in making an early diagnosis of this disease. To our knowledge this is the first case of Churg–Strauss syndrome primarily presenting with otological pathology: left sensorineural hearing loss and right otitis media.
Microdebrider removal of tracheal papilloma via tracheostomy in the child with an obliterated larynx
Authors: Ulualp S O , Ryan M W , Wright S T
Published: April 2007

In children, recurrent respiratory papillomatosis is the most common benign neoplasm of the airway. The disease frequently involves the larynx and may spread to extralaryngeal sites. Use of a microdebrider has been suggested as a safe and low-cost technique which reduces operating time, compared with laser removal of laryngeal lesions.

We describe a technique for using a microdebrider to remove tracheal papillomas when the larynx is obliterated with the disease.
Is Globalization Good for Workers? Definitions and Evidence from Latin America
Authors: Reinecke Gerhard
Published: April 2007

Is globalization good for workers? Many scholars have surprisingly clear-cut answers. “Globalization is good for workers,” say most economists. “Globalization is bad for workers,” say most sociologists, anthropologists, and historians. This article takes a more cautious approach, defining first the different dimensions of employment quality which can be measured in order to track changes (Section 2). In a second step, it reviews some of the mechanisms through which globalization could either benefit or harm workers, both through changes in labor demand and new patterns of work organization in response to globalization (Section 3). Thirdly, the paper presents summaries of statistical data and existing studies of Latin-American countries (Section 4). Finally, in order to understand some of the more qualitative aspects of the impact of globalization on labor, Section 5 presents evidence from sectoral case studies for one Latin-American country, Chile. Section 6 concludes.
Homological realization of prescribed abelian groups via K-theory
Authors: BERRICK A. J. , MATTHEY M.
Published: April 2007

Using algebraic and topological K-theory together with complex C*-algebras, we prove that every abelian group may be realized as the centre of a strongly torsion generated group whose integral homology is zero in dimension one and isomorphic to two arbitrarily prescribed abelian groups in dimensions two and three.
On positive cosine sums
Authors: BROWN GAVIN , DAI FENG , WANG KUNYANG
Published: April 2007

For α∈ (0,1) and x∈ [0,π, we define S0(x,α) = 1 and

where

Also, we set, for α∈ (0,1),

where it is agreed that infØ =∞. It is shown in this paper that

and 8≤ N(α)<∞ if α0<α<α*, where α*:=0.33542. . . is the unique solution α∈ (0,1) of the equation

while α0= 0.308443. . . is the unique solution α∈ (0,1) of the equation

In the case α*<α<1, this extends a result of Brown, Wang and Wilson (1993).
Mission, Ministry and Masonry: The Challenge of Heritage Buildings for Christian Witness
Authors: Knowles Graeme
Published: April 2007

While it might be said that the present state of repair of the majority of the churches in use in England is better than it has ever been before, the congregations of England, whether they be Anglican, Roman Catholic, Methodist or Baptist, face the day by day challenge of maintaining a substantial section of the nation's built heritage. The 2006 Lyndwood Lecture, delivered at St Paul's Cathedral, London, on 15 November 2006, examines possible avenues for the funding of this work, looking at the models of state aid offered by other European countries. It also considers the tension that exists between the legal imperative to view our churches not only as historic monuments but also as local centres of mission and worship. Moving on from this theme of funding, the lecture then examines the problems faced by all denominations in disposing of buildings no longer required for divine worship. It questions why the Church should continue to pay for the upkeep of buildings it no longer needs, and concludes, in the words of T S Eliot, that the Church must be forever building.
Shy But Not Retiring
Authors: Graham Alec
Published: April 2007

ERIC KEMP Continuum, London, 2006, 285 pp (hardback £25.00) ISBN: 978-0-8264-8073-6
The Foundations of Medieval English Ecclesiastical History: Studies Presented to David Smith
Authors: Watkin Thomas Glyn
Published: April 2007

PHILIPPA HOSKIN, CHRISTOPHER BROOKE AND BARRIE DOBSON Studies in the History of Medieval Religion, Vol 27, Boydell Press, Woodbridge,
2005, 248 pp (hardback £50.00) ISBN: 978-1-84383-169-3
Aerosols at a mountaintop observatory in Arizona
Authors: Shaw Glenn E.
Published: April 2007

This paper discusses physics of aerosols measured at the summit of Mt. Lemmon, Arizona (2790 m), from February to May 2002, where “clean” air representative of the free troposphere sometimes occurs. We confirmed Marti's findings of a persistent daily variation in the number concentration of condensation nuclei (diameter > 10 nm), with a strong maximum occurring in the afternoon and minimum in the early morning. These particles show evidence of growth at rates of 10–23 nm per hour. The diurnal variation was present even on days when the planetary boundary layer remained below the mountain. From the rate of growth and Maxwellian diffusion theory, we deduce that precursor condensable species are present in daytime concentrations of 107–108 cm−3, and that these are produced at a rate of 105–106 cm−3 s−1. Increased convection caused by solar heating of the mountain often carries contaminated air to the summit. Yet only a small (factor of 1.5) diurnal pattern was found for accumulation mode (diameter ∼ 130 nm) particles on days where the convective boundary layer passed well above the station. We hypothesize that these long‐lived (e.g., several days) aerosols are pumped into the free troposphere and remain behind at night in a residual layer. The free tropospheric aerosol size distribution measured at Mt. Lemmon was similar in shape but higher in magnitude (by around 50%) than at Jungfraujoch in the Swiss Alps (3580 m). There is much greater diurnal variation in Aitken‐sized particles (daily factor of from 7 to 10) at Mt. Lemmon than observed at Jungfraujoch (factor of from 1.0 to 1.6), evidently arising from stronger photochemical rate of productions of precursor gases.
Magnetic phases in hemo‐ilmenite: Insight from low‐velocity and high‐field Mössbauer spectroscopy
Authors: Frandsen C. , Mørup S. , McEnroe S. A. , Robinson P. , Langenhorst F.
Published: April 2007

We have studied natural samples of hemo‐ilmenite (ilmenite with hematite exsolution lamellae) by use of Mössbauer spectroscopy. The samples are from the Allard Lake intrusion in Quebec. The stoichiometric compositions of the ilmenite host and the hematite lamellae are approximately Fe2+0.84Mg2+0.14Ti4+0.98Fe3+0.04O3 and Fe2+0.17Mg2+0.01Ti4+0.18Fe3+1.64O3, respectively. From low‐velocity Mössbauer measurements, the Fe2+ and Fe3+ components of the Fe2+‐substituted hematite and Fe3+‐substituted ilmenite, formed by incomplete exsolution of hematite and ilmenite, have been suggested identified. High‐field Mössbauer measurements, obtained at low‐temperature, indicate the presence of a minor ferrimagnetic component.
Observational characteristics of double tropopauses
Authors: Randel William J. , Seidel Dian J. , Pan Laura L.
Published: April 2007

Temperature profiles in the extratropics often exhibit multiple tropopauses (as defined using the lapse rate definition). In this work we study the observational characteristics of double tropopauses based on radiosondes, ERA40 reanalysis, and GPS radio occultation temperature profiles. Double tropopauses are associated with a characteristic break in the thermal tropopause near the subtropical jet, wherein the low latitude (tropical) tropopause extends to higher latitudes, overlying the lower tropopause; this behavior can extend to polar latitudes. Tropopause statistics derived from radiosondes and GPS data show good agreement, and GPS data allow mapping of double tropopause characteristics over the globe. The occurrence frequency shows a strong seasonal variation over NH midlatitudes, with ∼50–70% occurrence in profiles during winter, and a small fraction (∼10%) over most of the hemisphere during summer (with the exception of a localized maximum over the poleward flank of the Asian monsoon anticyclone). SH midlatitude statistics show a smaller seasonal variation, with occurrence frequencies of ∼30–50% over the year (maximum during winter). Over the extratropics, the occurrence frequency is substantially higher for cyclonic circulation systems. Few double tropopauses are observed in the tropics. Ozone measurements from balloons and satellites show that profiles with double tropopauses exhibit systematically less ozone in the lower stratosphere than those with a single tropopause. Together with the meteorological data, the ozone observations identify double tropopauses as regions of enhanced transport from the tropics to higher latitudes above the subtropical jet cores.
On the tropospheric origin of Mesosphere Lower Thermosphere region intraseasonal wind variability
Authors: Kumar Karanam Kishore , Antonita T. M. , Ramkumar G. , Deepa V. , Gurubaran S. , Rajaram R.
Published: April 2007

Continuous medium frequency radar observations of mesosphere lower thermosphere (MLT) region winds during February 2004–May 2005 (486 days) over Tirunelveli (8.7°N, 77.8°E) revealed intraseasonal oscillations (ISOs) in the 82‐ to 94‐km height region. Two distinct oscillations with periods 50–70 and 20–40 days are noticed predominantly in zonal winds. As it is well established that these oscillations are nonstationary and localized in time, wavelet analysis has been employed to study the time evolution of these oscillations. The analysis showed that 50‐ to 70‐day oscillation peaks during June‐October and 20‐ to 40‐day oscillation peaks during January‐March in the MLT region. To trace back the origin of these oscillations, the tropospheric ISO has been studied for the same period using outgoing long‐wave radiation (OLR) observations. The OLR, which is the proxy for convective activity in the lower atmosphere, around the radar site 5–10°N, 70–80°E is used for the present analysis. The wavelet analysis of OLR showed the 50‐ to 70‐day oscillation peaking at the same time as in the MLT region. The shorter period oscillation (20–40 days), which showed its peak during January‐March in the MLT region, is not observed in the OLR data during these months. However, the analysis of water vapor, which is the prime candidate for excitation of tides, showed the 20‐ to 40‐day oscillation during the same time as in the MLT region. In the present study, the lower atmospheric convective activity through gravity wave excitation and water vapor through tidal forcing are accounted for the observed ISO in the MLT region. The significance of present results lies in showing the highly coherent oscillations in OLR and MLT region zonal winds. The coupling between the lower and middle atmospheric ISO is extensively discussed in the light of existing mechanisms.
Feasibility of reconstructing paleoatmospheric records of selected alkanes, methyl halides, and sulfur gases from Greenland ice cores
Authors: Aydin M. , Williams M. B. , Saltzman E. S.
Published: April 2007

Seven short‐lived atmospheric trace gases were measured in 25 ice core samples from Summit, Greenland. Samples were selected from contemporaneous sections of fluid‐ and dry‐drilled ice cores to examine what effects using n‐butyl acetate as the drill fluid would have on the measurements. The gases include three light alkanes, C2H6, C3H6, and n‐C4H10; two methyl halides, CH3Cl and CH3Br; and two sulfur compounds, OCS and CS2, with gas ages from 125 to 325 years before present. Alkane levels are comparable to measurements in modern Arctic air, although C2H6 exhibits greater variability than expected compared with C3H6 and n‐C4H10. These results are not consistent with the idea that the alkanes are primarily of anthropogenic origin, suggesting that the ice cores may not truly record a paleoatmospheric signal with respect to these gases. The CH3Br results are consistent with previous observations of “excess” CH3Br in Greenland firn air. In situ production processes appear to overwhelm the paleoatmospheric signal of this gas. CH3Cl exhibits the same effect to a lesser extent. OCS levels are similar to those in Antarctic ice cores and appear to reflect paleoatmospheric levels. CS2 results are similar to the limited database of modern atmospheric measurements. Only C3H8 and n‐C4H10 exhibit clear evidence of contamination because of the presence of the drill fluid. The results indicate that it is possible to analyze many trace gases in fluid‐ and dry‐drilled ice samples. However, it appears that in situ production may significantly alter the levels of some trace gases in Greenland ice cores.
Nox2-Derived Reactive Oxygen Species Mediate Neurovascular Dysregulation in the Aging Mouse Brain
Authors: Park Laibaik , Anrather Josef , Girouard Helene , Zhou Ping , Iadecola Costantino
Published: April 2007

Aging is associated with cerebrovascular dysregulation, which may underlie the increased susceptibility to ischemic stroke and vascular cognitive impairment occurring in the elder individuals. Although it has long been known that oxidative stress is responsible for the cerebrovascular dysfunction, the enzymatic system(s) generating the reactive oxygen species (ROS) have not been identified. In this study, we investigated whether the superoxide-producing enzyme NADPH oxidase is involved in alterations of neurovascular regulation induced by aging. Cerebral blood flow (CBF) was recorded by laser-Doppler flowmetry in anesthetized C57BL/6 mice equipped with a cranial window (age = 3, 12, and 24 months). In 12-month-old mice, the CBF increases evoked by whisker stimulation or by the endothelium-dependent vasodilators acetylcholine and bradykinin were attenuated by 42, 36, and 53%, respectively ( P < 0.05). In contrast, responses to the nitric oxide donor S-nitroso-D-penicillamine or adenosine were not attenuated ( P > 0.05). These cerebrovascular effects were associated with increased production of ROS in neurons and cerebral blood vessels, assessed by hydroethidine microfluorography. The cerebrovascular impairment present in 12-month-old mice was reversed by the ROS scavenger Mn (III) tetrakis (4-benzoic acid) porphyrin chloride or by the NADPH oxidase peptide inhibitor gp91ds-tat, and was not observed in mice lacking the Nox2 subunit of NADPH oxidase. These findings establish Nox2 as a critical source of the neurovascular oxidative stress mediating the deleterious cerebrovascular effects associated with increasing age.
Trade Agreements and Public Health: Are US Trade Negotiators Building an Intellectual Property Platform against the Generic Industry? Are They Raising the Standards to Go beyond the US Law?
Authors: Jorge María Fabiana
Published: April 2007

The United States Trade Representative (USTR) is negotiating bilateral free trade agreements that favour patent holders at the expense of the generic industry and consumers. In doing so, the USTR is breaking the balance between innovation and access struck in the US under the Hatch-Waxman Act. Furthermore, although trade agreements negotiated by the US government should seek to foster exports by US companies, these agreements clearly hinder the export of US generic drugs. In addition, these agreements are putting US consumers' access to generic drugs at considerable risk in the event of international patent law harmonisation.
Finite temperature phase transition in the three-dimensional Heisenberg ±J spin glass model
Authors: Beath A. D. , Ryan D. H.
Published: April 2007

The three-dimensional Heisenberg spin glass model with ±J interactions is studied using an over-relaxed Monte Carlo algorithm. We have measured the correlation length ξ, and using the crossing of ξ∕L for different L find a finite temperature spin glass transition, with TSG=0.220(5). In addition, we have varied the number of Monte Carlo steps used prior to, and during, thermal averaging to control the effects of finite time averaging. We find that the over-relaxation algorithm allows for an accurate measurements using as few as 300 Monte Carlo steps.
Material characterization with ramp wave experiments
Authors: Ding J. L. , Asay J. R.
Published: April 2007

Ramp wave experiments on the Sandia Z accelerator provide a different approach to study the rapid compression response of materials at pressures, temperatures, and stress or strain rates not attainable in conventional shock experiments. Due to its shockless nature, the ramp wave experiment is often termed as an isentropic (or quasi-isentropic) compression experiment (ICE) and the analysis of ICE has been focused on determination of the isentropes. One objective of the current study is to show that ramp wave experiment can be used as a much more general material characterization tool for studying material behavior under high strain rates and pressures. The second objective is to suggest practical methodology to design the experiment and analyze experimental data. Numerical simulations were used to achieve these objectives. It is demonstrated that the ramp wave experiment is essentially a controlled-strain-rate material test. The strain rate can be varied through the rise time and shape of the ramp wave. The resultant stress-strain relation is a specific relation for a specific strain-rate history. The isentrope, which is a limiting case of such relations, may be approximated through a very low strain-rate loading path. Because of the rate dependence of the material behavior, each material point experiences different strain-rate loading paths. Lagrangian analysis requires information pertinent to a local Lagrangian material point. This information may be obtained through a pair of wave profiles measured at two very close, but essentially the same, Lagrangian points.
Magnetoresistance of magnetic tunnel junctions with low barrier heights
Authors: Beletskii N. N. , Berman G. P. , Borysenko S. A. , Wolf S. A. , Yakovenko V. M.
Published: April 2007

The magnetoresistance of low-barrier magnetic tunnel junctions (MTJs) was studied within a two-band model of free electrons in ferromagnetic electrodes, taking into consideration image forces. For MTJs with an MgO insulator, explanations are given of the giant tunneling magnetoresistance (TMR) effect and the effect of increasing TMR as the width of the MgO barrier increases. It is shown that TMR and the electron current density through MTJs depend strongly on the dielectric constant of the MgO insulator. It is found that the TMR of low-barrier MTJs reaches a maximum at a particular value of the applied bias voltage. It is demonstrated that the electron current density through low-barrier MTJs can be high enough to switch the magnetization of a ferromagnetic electrode.
Gyrokinetic analysis of linear microinstabilities for the stellarator Wendelstein 7-X
Authors: Xanthopoulos P. , Jenko F.
Published: April 2007

A linear collisionless gyrokinetic investigation of ion temperature gradient (ITG) modes—considering both adiabatic and full electron dynamics—and trapped electron modes (TEMs) is presented for the stellarator Wendelstein 7-X (W7-X) [G. Grieger et al., Plasma Physics and Controlled Nuclear Fusion Research 1990 (International Atomic Energy Agency, Vienna, 1991), Vol. 3, p. 525]. The study of ITG modes reveals that in W7-X, microinstabilities of distinct character coexist. The effect of changes in the density gradient and temperature ratio is discussed. Substantial differences with respect to the axisymmetric geometry appear in W7-X, concerning the relative separation of regions with a large fraction of helically trapped particles and those of pronounced bad curvature. For both ITG modes and TEMs, the dependence of their linear growth rates on the background gradients is studied along with their parallel mode structure.
Influence of mixing the low-valent transition metal atoms (Y, Y*=Cr, Mn, Fe) on the properties of the quaternary Co2[Y1−xYx*]Z (Z=Al, Ga, Si, Ge, or Sn) Heusler compounds
Authors: Özdoğan K. , Aktaş B. , Galanakis I. , Şaşıoğlu E.
Published: April 2007

We complement our study on the doping and disorder in Co2MnZ compounds [I. Galanakis, K. Özdoğan, B. Aktaş, and E. Şaşıoğlu, Appl. Phys. Lett. 89, 042502 (2006) and K. Özdoğan, E. Şaşıoğlu, B. Aktaş, and I. Galanakis, Phys. Rev. B 74, 172412 (2006)] to cover also the quaternary Co2[Y1−xYx∗]Z compounds with the lower-valent transition metals Y, Y∗ being Cr, Mn, or Fe and the sp atom Z being one of Al, Ga, Si, Ge, and Sn. This study gives a global overview of the magnetic and electronic properties of these compounds since we vary both Y and Z elements. Our results suggest that for realistic applications the most appropriate compounds are the ones belonging to the families Co2[Mn1−xCrx]Z with x>0.5 irrespectively of the nature of the sp atoms since they combine high values of majority density of states at the Fermi level due to the presence of Cr, and half-metallicity with large band gaps. On the other hand, the presence of Fe considerably lowers the majority density of states at the Fermi level and when combined with an element belonging to the Si column, it can even destroy half-metallicity.
Optimized molecular force field for sulfur hexafluoride simulations
Authors: Olivet Aurelio , Vega Lourdes F.
Published: April 2007

An optimized molecular force field for sulfur hexafluoride (SF6) simulations is presented in this work. The new force field for SF6 contains two parts: a Lennard-Jones potential that deals with F–F intermolecular interactions and the second term dealing with the intramolecular forces. In this second part the flexibility of the molecule is explicitly considered by 6 harmonic stretch terms, modeling the S–F chemical bonds, and 12 harmonic bending terms, modeling the F–S–F angular deformations. The parameters of the new force field have been obtained by a multivariable optimization procedure, whose main feature is the simultaneous fitting of all force field parameters, using as reference data several equilibrium properties (vapor pressure, saturated liquid density, and surface tension) and shear viscosity. The new force field clearly improves the description of the phase envelope and the rest of the properties as compared to previous simulations for a rigid model for the same molecule [A. Olivet et al., J. Chem. Phys. 123, 194508 (2005)]. Results for the optimized force field concerning the vapor-liquid coexistence curve, several thermodynamics states at the homogeneous gas and liquid region, and transport coefficients of SF6 are in good agreement with available experimental data.
Local and semilocal density functional computations for crystals of 1-alkyl-3-methyl-imidazolium salts
Authors: Del Pópolo M. G. , Pinilla C. , Ballone P.
Published: April 2007

The accuracy and reliability of popular density functional approximations for the compounds giving origin to room temperature ionic liquids have been assessed by computing the T=0K crystal structure of several 1-alkyl-3-methyl-imidazolium salts. Two prototypical exchange-correlation approximations have been considered, i.e., the local density approximation (LDA) and one gradient corrected scheme [PBE-GGA, Phys. Rev. Lett. 77, 3865 (1996)]. Comparison with low-temperature x-ray diffraction data shows that the equilibrium volume predicted by either approximations is affected by large errors, nearly equal in magnitude (∼10%), and of opposite sign. In both cases the error can be traced to a poor description of the intermolecular interactions, while the intramolecular structure is fairly well reproduced by LDA and PBE-GGA. The PBE-GGA optimization of atomic positions within the experimental unit cell provides results in good agreement with the x-ray structure. The correct system volume can also be restored by supplementing PBE-GGA with empirical dispersion terms reproducing the r−6 attractive tail of the van der Waals interactions.
Impedance of a planar solenoid with a thin magnetic core
Authors: Rejaei Behzad , Vroubel Marina
Published: April 2007

The high-frequency impedance of a planar solenoid with a thin magnetic core is theoretically investigated using the magnetostatic Green’s function formalism. It is shown that the electrical behavior of the solenoid depends on how the magnetic field induced by the current-carrying coil is coupled to the different magnetostatic modes of the core. The magnetic response of the core in each mode is determined by an effective susceptibility matrix which depends on exact, but mode-dependent demagnetization factors. Those factors determine the frequency of the magnetostatic excitations of the core, manifested as resonances in the impedance of the solenoid. Using the formalism developed, the effect of the core width and magnetic loss on the impedance of the device is studied.
Fast numerical three-dimensional scheme for the simulation of hysteresis in ferromagnetic grains
Authors: Van de Wiele Ben , Olyslager Femke , Dupré Luc
Published: April 2007

The magnetic behavior of ferromagnetic materials like iron is important for the improvement of performances of electromagnetic devices. This article deals with a three-dimensional model that computes the magnetic behavior of an iron grain under a varying applied field starting from its microscopic material parameters. The model can be used as a tool to determine the quantitative relations between the different microscopic parameters and their influence on the magnetic properties of the grain. The magnetization dynamics are computed for successive quasistatic applied fields. In each space point of the grain, the time variation of the magnetic dipole M is described by the Landau-Lifshitz equation. To integrate this equation, two time stepping schemes are proposed: a forward semianalytical and a predictor-corrector time stepping scheme. The two methods obey the two intrinsic properties of the Landau-Lifshitz equation: (1) preservation of the amplitude of the magnetic dipoles and (2) the decrease of the total free energy when a constant field is applied. They also have a good time and memory efficiency, while the predictor-corrector semianalytical scheme has the best precision and convergence properties. The optimal time stepping scheme and corresponding time stepping parameters are determined. The proposed model is adapted to several experiments, varying different microscopic parameters. In the numerical computations, the spatial discretization is obtained by finite different techniques and the magnetostatic field is computed using fast Fourier transforms.
Symmetry segregation of the vibronic levels within the S1←S system of thiophosgene, Cl2CS, by optical-optical double resonance spectroscopy
Authors: Fujiwara Takashige , Lim Edward C. , Moule David C.
Published: April 2007

The first singlet-singlet electronic system, S1←S0, in thiophosgene has been recorded as a laser induced fluorescence (LIF) excitation and an optical-optical double resonance (OODR) spectrum under jet-cooled conditions. In the OODR process, the sum of the frequencies of the pump and probe lasers must be fixed to the energy difference between a pair of vibronic levels in the S2(v′) and S0(v″) states. Detection is through the fluorescence from the S2 state. The blocking of a spectrum into its four possible symmetry components is obtained by adjusting the total pump+probe energy such that it matches the energy difference between symmetry selected levels in the S2 and S0 electronic states. In this method the pump laser is used to excite a group of “hot” sequence bands that involve combinations of the ν4 and ν6 antisymmetric vibrations. The additional data that were collected by this method were used to update and refine the analyses of the spectrum. Magnetic dipole transitions are reported for the first time.
Heteropolymer translocation through nanopores
Authors: Luo Kaifu , Ala-Nissila Tapio , Ying See-Chen , Bhattacharya Aniket
Published: April 2007

The authors investigate the translocation dynamics of heteropolymers driven through a nanopore using a constant temperature Langevin thermostat. Specifically, they consider heteropolymers consisting of two types of monomers labeled A and B, which are distinguished by the magnitude of the driving force that they experience inside the pore. From a series of studies on polymers with sequences AmBn the authors identify both universal as well as specific sequence properties of the translocating chains. They find that the scaling of the average translocation time as a function of the chain length N remains unaffected by the heterogeneity, while the residence time of each bead is a strong function of the sequence for short repeat units. They further discover that for a symmetric heteropolymer AnBn of fixed length, the pattern exhibited by the residence times of the individual monomers has striking similarity with a double slit interference pattern where the total number of repeat units N∕2n controls the number of interference fringes. These results are relevant for designing nanopore based sequencing techniques.
Spin-transfer induced noise in nanoscale magnetoresistive sensors
Authors: Sbiaa R. , Piramanayagam S. N.
Published: April 2007

The transfer of spin angular momentum from a polarized current to a ferromagnet can induce reversal of magnetization and generation of spin waves. In this article, we present micromagnetic simulations of magnetization dynamics in spin valve structure under effect of spin-polarized current and external magnetic field. Unlike the previous studies, the magnetizations of pinned layer, and the free layer in this study are orthogonal. Such a configuration, which is closer to that of the spin-valve sensors, shows many interesting results such as the observation of steady and oscillatory states.
Quantum fluctuation of tunneling current in individual Ge quantum dots induced by a single-electron transfer
Authors: Nakamura Yoshiaki , Ichikawa Masakazu , Watanabe Kentaro , Hatsugai Yasuhiro
Published: April 2007

A scanning tunneling microscopic study revealed quantum fluctuation of tunneling currents in individual Ge quantum dots (QDs) on SiO2∕Si. This was due to the charging energy change in the QDs caused by single-electron transfer from or into the QDs. The observed electron discharging time of approximately milliseconds agreed with the propagation model of the electron wave packets from the QDs to the Si substrates by a tunneling effect rather than by passing through voids in the SiO2 smaller than electron de Broglie wavelength.
Extended electronic states above metal-doped carbon nanostructures
Authors: Stoyanov Stanislav R. , Král Petr , Wang Boyang
Published: April 2007

Spatially extended electronic states formed above metal atoms covalently attached to carbon nanostructures are presented by ab initio calculations. These extended states are largely composed of the unpopulated 5–6s atomic orbitals of the metal atom. They could be manipulated by electric and optical fields and used in electron emission. The metallic sites can also facilitate binding and releasing of ions, atoms, and molecular ligands, so the structures can serve as “atomic nanotools.”
Development of green, yellow, and amber light emitting diodes using InGaN multiple quantum well structures
Authors: Barletta Philip T. , Acar Berkman E. , Moody Baxter F. , El-Masry Nadia A. , Emara Ahmed M. , Reed Mason J. , Bedair S. M.
Published: April 2007

The authors present optical and electrical data for long wavelength (573–601nm) InGaN∕GaN multiple quantum well light emitting diodes (LEDs) grown by metal organic chemical vapor deposition. These results are achieved by optimizing the active layer growth temperature and the quantum well width. Also, the p-GaN is grown at low temperature to avoid the disintegration of the InGaN quantum wells with high InN content. A redshift is observed for both the green and yellow LEDs upon decreasing the injection current at low current regime. In the case of the yellow LED, this shift is enough to push emission into the amber (601nm).
Memory effects in metal-oxide-semiconductor capacitors incorporating dispensed highly monodisperse 1nm silicon nanoparticles
Authors: Nayfeh Osama M. , Antoniadis Dimitri A. , Mantey Kevin , Nayfeh Munir H.
Published: April 2007

Metal-oxide-semiconductor capacitors containing various densities of ex situ produced, colloidal, highly monodisperse, spherical, 1nm silicon nanoparticles were fabricated and evaluated for potential use as charge storage elements in future nonvolatile memory devices. The capacitance-voltage characteristics are well behaved and agree with similarly fabricated zero-nanoparticle control samples and with an ideal simulation. Unlike larger particle systems, the demonstrated memory effect exhibits effectively pure hole storage. The nature of charging, hole type versus electron type may be understood in terms of the characteristics of ultrasmall silicon nanoparticles: large energy gap, large charging energy, and consequently a small electron affinity.
On the design of capacitive sensors using flexible electrodes for multipurpose measurements
Authors: Thibault Pierre , Diribarne Pantxo , Fournier Thierry , Perraud Sylvain , Puech Laurent , Wolf P.-Etienne , Rousset Bernard , Vallcorba Roser
Published: April 2007

This article evaluates the potential of capacitive measurements using flexible electrodes to access various physical quantities. These electrodes are made of a thin metallic film, typical thickness 0.2 μm, evaporated on a plastic substrate. Their large flexibility enables them to be mounted in complex geometries such as curved surfaces. In the configuration of planar condensers, using a very sensitive commercial capacitive bridge and a three-terminal measurement method, several measurements are presented. A relative resolution of 10−8 for the thermal expansion of samples is obtained at low temperature in a differential configuration. The same technique adopted for pressure gauge measurements at low temperature led to a typical 0.1 Pa resolution over a dynamic range of 104 Pa. In the configuration of interleaved electrodes, condensers have been used to measure wetting by either bulk liquid helium or by thin continuous helium films in a cylindrical pipe. Both experimental and numerical evidence is provided, showing that the close proximity of a reference ground potential significantly increases the relative sensitivity to fluid wetting. Further, interleaved electrodes can be used to access both the area that is covered by a liquid film but also to determine the thickness of this film, provided it is comparable to the periodicity of the electrode pattern.