bluuebunny/crossref_metadata_2025 huggingface dataset:
Improvement of X‐ray diffraction geometries of water physisorbed in zeolites on the basis of periodic Hartree–Fock calculations
Authors: Larin A. V. , Trubnikov D. N. , Vercauteren D. P.
Published: January 2005

Improvements to the experimental X‐ray diffraction (XRD) coordinates of water adsorbed in three cationic zeolites as well as to the coordinates of the framework atoms is suggested on the basis of periodic DFT (PDFT) and Hartree–Fock (PHF) calculations. After an initial optimization of either the water coordinates solely or the water/zeolite framework coordinates with the minimal STO‐3G basis set, a scaling procedure is proposed to improve the water OH bond lengths and HOH angle up to a higher quality basis set level. It is followed by a discussion on the similarity of the hydrogen bond characteristics between water clusters and the adsorbed state. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Three‐query PCPs with perfect completeness over non‐Boolean domains
Authors: Engebretsen Lars , Holmerin Jonas
Published: January 2005

We study non‐Boolean PCPs that have perfect completeness and query three positions in the proof. For the case when the proof consists of values from a domain of sizedfor some integer constantd≥ 2, we construct a nonadaptive PCP with perfect completeness and soundnessd−1+d−2+ ϵ, for any constant ϵ > 0, and an adaptive PCP with perfect completeness and soundnessd−1+ ϵ, for any constant ϵ > 0. The latter PCP can be converted into a nonadaptive PCP with perfect completeness and soundnessd−1+ ϵ, for any constant ϵ > 0, where four positions are read from the proof. These results match the best known constructions for the cased= 2 and our proofs also show that the particular predicates we use in our PCPs are nonapproximable beyond the random assignment threshold. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2005
Allosteric regulation of the higher plant ADP‐glucose pyrophosphorylase is a product of synergy between the two subunits
Authors: Hwang Seon-Kap , Salamone Peter R. , Okita Thomas W.
Published: January 2005

The higher plant ADP‐glucose pyrophosphorylase (AGPase) is a heterotetramer consisting of two regulatory large subunits (LSs) and two catalytic small subunits (SSs). To further characterize the roles of these subunits in determining enzyme function, different combinations of wildtype LS (LWT) and variant forms (LUpReg1, LM345) were co‐expressed with wildtype SS (SWT) and variant forms (STG‐15 and Sdevo330) and their enzyme properties compared to those measured for the heterotetrameric wildtype enzyme and SS homotetrameric enzymes. Analysis of the allosteric regulatory properties of the various enzymes indicates that although the LS is required for optimal activation by 3‐phosphoglyceric acid and resistance to Pi, the overall allosteric regulatory and kinetic properties are specified by both subunits. Our results show that the regulatory and kinetic properties of AGPase are not simply due to the LS modulating the properties of the SS but, instead, are a product of synergistic interaction between the two subunits.
N‐terminal peptide of Rhizopus oryzae lipase is important for its catalytic properties
Authors: Sayari Adel , Frikha Fakher , Miled Nabil , Mtibaa Hounaida , Ali Yassine Ben , Verger Robert , Gargouri Youssef
Published: January 2005

In a culture medium, the Rhizopus oryzae strain produces only one form of lipase, ROL32. When the concentrated culture medium was stored at 0 °C during several months or kept at 6 °C during a few days, we noticed the appearance of a second shorter form of ROL32 lacking its N‐terminal 28 amino acid (ROL29). ROL29 was purified to homogeneity and its 21 N‐terminal amino acid residues were found to be identical to the 29–49 sequence of ROL32. The cleavage of the N‐terminal peptide reduced the specific activity of ROL29 by 50% using either triolein or tributyrin as substrates. In order to explain this decrease of the specific activity of ROL29, we measured its critical surface pressure of penetration into phosphatidyl choline from egg yolk films which was found to be 10 mN/m, in contrast to a value of 23 mN/m found in ROL32. A kinetic study on the surface pressure dependency, stereoselectivity and regioselectivity of ROL29 was performed using the three dicaprin isomers spread as monomolecular films at the air–water interface. Our results showed that in contrast to ROL32, ROL29 presented a preference for the distal ester groups of one diglyceride isomer (1,3‐sn‐dicaprin). Furthermore, ROL32 was markedly more stereoselective than ROL29 for the sn‐3 position of the 2,3‐sn‐enantiomer of dicaprin. A structural explanation of the enhanced penetration capacity as well as the catalytic activity of ROL32 was proposed by molecular modeling. We concluded that the N‐terminal peptide of ROL32 can play an important role in the specific activity, the regioselectivity, the stereoselectivity and the binding of the enzyme to its substrate.
Isolation and functional characterization of a novel plastidic hexokinase from Nicotiana tabacum
Authors: Giese Jens-Otto , Herbers Karin , Hoffmann Manuela , Klösgen Ralf Bernd , Sonnewald Uwe
Published: January 2005

Due to their central role in sugar metabolism and signalling plant hexokinases have been studied in great detail, however, little is known about the spatial and temporal expression and the sub‐cellular distribution of individual hexokinase isoforms. Based on in planta and in vitro studies the recently isolated tobacco hexokinase 2 (Hxk2) could be located in the chloroplast stroma and biochemically characterized. Hxk2 represents the first innerplastidic hexokinase described from higher plants. Promoter studies indicate that Hxk2 is mainly expressed in cells of the vascular starch sheath and xylem parenchyma, in guard cells and root tips. We propose a role for Hxk2 in starch and secondary metabolism in the mentioned tissues.
Marker-assisted introgression of the Compact mutant myostatin allele MstnCmpt-dl1Abc into a mouse line with extreme growth effects on body composition and muscularity
Authors: BÜNGER LUTZ , OTT GERHARD , VARGA LÁSZLÓ , SCHLOTE WERNER , REHFELDT CHARLOTTE , RENNE ULLA , WILLIAMS JOHN L. , HILL WILLIAM G.
Published: January 2005

Myostatin is a negative regulator of muscle growth and mutations in its gene lead to muscular hypertrophy and reduced fat. In cattle, this is seen in ‘double muscled’ breeds. We have used marker-assisted introgression to introduce a murine myostatin mutation, MstnCmpt-dl1Abc [Compact (C)], into an inbred line of mice (DUHi) that had been selected on body weight and had exceptional growth. Compared with homozygous wild-type mice, homozygous (C/C) mice of this line were ~4–5% lighter, had ~7–8% shorter tails, substantially increased muscle weights (e.g. quadriceps muscle in males was 59% heavier) and an increased ‘dressing percentage’ (~49% vs 39%), an indicator of overall muscularity. The weights of several organs (e.g. liver, kidney, heart and digestive tract) were significantly reduced, by 12–20%. Myostatin deficiency also resulted in drastic reductions of total body fat and of various fat depots, total body fat proportion falling from ~17·5% in wild-type animals of both sexes to 9·5% and 11·6% in homozygous (C/C) females and males, respectively. Males with a deficiency in myostatin had higher gains in muscle traits than females. Additionally, there was a strong distortion of the segregation ratio on the DUHi background. Of 838 genotyped pups from inter se matings 29%, 63% and 8% were homozygous wild type (+/+), heterozygous (C/+) and homozygous (C/C), respectively, showing that MstnCmpt-dl1Abc has lower fitness on this background. This line, when congenic, will be a useful resource in gene expression studies and for finding modifying genes.
Identification of a cryptic lethal mutation in the mouse tw73 haplotype
Authors: HOWELL GARETH R. , BERGSTROM REBECCA A. , MUNROE ROBERT J. , MASSE JESSICA , SCHIMENTI JOHN C.
Published: January 2005

t haplotypes are naturally occurring, variant forms of the t complex on mouse chromosome 17, characterized by the presence of four inversions with respect to wild-type. They harbour mutations causing male sterility, male transmission ratio distortion (TRD) and embryonic lethality. Mice carrying t haplotypes have been found throughout the world, and genetic studies of the lethal mutations have identified at least 16 complementation groups. The embryonic lethal phenotypes of many t haplotypes have been characterized in detail, and are thought to be the consequence of homozygosity for single gene mutations. However, the existence of additional mutations in genes that function at later stages of development would be obscured. Here we investigated the possibility of multiple mutations in t haplotypes by screening the tw73 haplotype for the presence of novel mutations. Since genetic analysis of t haplotype mutations is hindered by recombination suppression due to the inversions, deletion complexes covering the proximal two-thirds of the t complex were used to uncover the presence of any new lethal alleles. This analysis revealed a novel mutation between D17Jcs41 and D17Mit100, causing mice carrying both tw73 and selected deletions to die at birth, prior to feeding. The finding of a new, cryptic lethal mutation in t haplotypes is an indication that these recombinationally isolated chromosomes, which already contain at least one lethal mutation that prevents homozygosity, may serve as sinks for the accumulation of additional recessive mutations.
High variability of milk protein genes in Bos indicus cattle breeds of Cameroon and Nigeria and characterization of a new αs1-casein promoter allele
Authors: Ibeagha-Awemu Eveline M , Prinzenberg Eva-Maria , Erhardt Georg
Published: January 2005

The study provides the first comprehensive information on the variability of milk protein genes of Bos indicus and Bos taurus cattle breeds in Cameroon and Nigeria. The investigations indicate a high diversity of milk protein genes for the zebu populations. Of the investigated alleles, 21 out of 29 were observed. The method of single strand conformation polymorphism (SSCP) was a particularly useful technique because it allowed discrimination of alleles, including zebu-specific alleles at the CSN2 (I) and CSN3 (AI and H) loci, not separated by protein electrophoretic techniques and also made possible the detection of a further CSN1S1 5′ promoter allele (CSN1S1Prom5), which is also zebu-specific. Characterization of CSN1S1Prom5 showed that it was the most variable of all described CSN1S1 promoter alleles. A potential GATA consensus motif is created by mutations in CSN1S1Prom5. Intra-breed diversity measured as mean effective number of alleles was higher in the zebu populations than in the taurine breeds. Of the expected casein haplotypes, 96 out of 320 were present in the studied breeds. 2-C-A-A2-H (CSN1S1Prom2-CSN1S1C-CSN1S2A-CSN2A2-CSN3H) and 5-C-A-A2-H were zebu-specific while 1-B-A-A2-B was specific to the taurines. Overall distribution of alleles and haplotypes clearly separated the zebu populations from the taurine breeds. Zebu influence on the taurine breed Namchi was detected through the occurrence of zebu alleles and haplotypes. High variability of milk proteins also means availability of resources for breed development, phylogenetic studies, and conservation and management decisions.
Chemical and rheological aspects of gel formation in the California Mastitis Test
Authors: Whyte David , Walmsley Michael , Liew Alvin , Claycomb Rod , Mein Graeme
Published: January 2005

The rheological properties of the CMT gel were analysed. Data are presented to demonstrate that the gel is a non-homogenous, visco-elastic, non-Newtonian fluid with rheopectic, and rheodestructive behaviour. The fundamental chemistry of the CMT is reviewed and a modified theory of gel formation is presented. The implications of the rheological properties and modified theory of gel formation for an automatic sensor are discussed.
Dietary trans octadecenoic acids upregulate the liver gene encoding Peroxisome Proliferator-Activated Receptor-α in transition dairy cows
Authors: Selberg Kurt T , Staples Charles R , Dan Luchini N , Badinga Lokenga
Published: January 2005

Effects of feeding calcium salts of conjugated linoleic acid (CLA) or trans octadecenoic acids (trans 18[ratio ]1) on lipid metabolism and hepatic contents of mRNA encoding carnitine palmitoyltransferase 1 (CPT1), microsomal triglyceride transfer protein (MTP) and peroxisome proliferator-activated receptor alpha (PPARα) were examined in 15 early post-partum Holstein cows. Dietary treatments were initiated at approximately 4 weeks prior to expected calving dates and continued for 7 weeks post partum. Treatments prepartum consisted of 1) a basal diet (Control), 2) basal diet+150 g/d of CLA mix (CLA), or 3) basal diet+150 g/d of trans 18[ratio ]1 mix (TRANS). Intakes of calcium salts of CLA and trans 18[ratio ]1 mixes were adjusted to 225 g/d during the 7-week post-partum treatment period. Blood samples were collected at weeks 1, 2 and 4 post partum and plasma was harvested immediately for subsequent hormone and metabolite assays. Concentrations of insulin, insulin-like growth factor-I (IGF-I), and leptin in blood did not vary among cows fed the three diets. Plasma nonesterified fatty acid (NEFA) concentrations decreased between weeks 1 and 4 of lactation and were lower in cows fed the diet supplemented with trans 18[ratio ]1 than in those fed a control diet at week 2 post partum. Periparturient fat supplementation had no detectable effects on CPT1 mRNA content in the liver. Steady-state concentration of MTP mRNA in the liver was greater in the TRANS treatment group than in the control group at week 1 post partum. Feeding trans 18[ratio ]1 supplements to transition dairy cows upregulated hepatic PPARα mRNA content during the first month of lactation. Under the present experimental conditions, dietary CLA had minimal effects on plasma and hepatic lipid metabolite concentrations in early lactation Holstein cows. Results indicate that dietary trans fatty acids may affect liver lipid metabolism in post-partum dairy cows through alterations in PPARα gene expression.
Video microscopy as an alternative method for somatic cell count in milk
Authors: Baro Jesús A , Roldán Patricia , Carleos Carlos E , Grillo Gustavo J , Pérez Miguel A
Published: January 2005

This paper presents an alternative method to estimate somatic cell count (SCC) in cows' milk. SCC is an important indicator in the detection of inflammatory reactions within the udder in cows and Direct Optical Microscopy (DOM) is the present reference method for SCC but, owing to its dependence on human operators, it is extremely costly, time-consuming and potentially subjective. The industrial method of choice is Epifluorescence (EF), which has the potential for impressive throughput and acceptable precision, but requires huge inversions and handling of highly toxic reactives and waste. In this paper, an advantageous method that involves application of a low-cost Video Microscopy (VM) system is analysed and discussed, including a comparison between DOM and VM, and an example of application of both methods to evaluate EF counts. We conclude that VM is sufficiently precise and very cheap to implement and operate.
Effects of hormones and growth factors on TGF-β1 expression in bovine mammary epithelial cells
Authors: Zarzyńska Joanna , Gajewska Małgorzata , Motyl Tomasz
Published: January 2005

The decline of mammary epithelial cell (MEC) number during mammary gland involution in the cow is due to inhibition of proliferation and induction of apoptosis. Transforming growth factor-beta 1 (TGF-β1) belongs to a group of intramammary auto/paracrine inhibitors of bovine MEC growth and inducers of apoptosis. However, the mechanism responsible for the regulation of TGF-β1 expression in MEC is not known. The present study examined the effect of the hormones, growth hormone (GH), somatostatin (STS), 17-β oestradiol (E2), progesterone (P4), as well as the growth factors, insulin-like growth factor I (IGF-I) and epidermal growth factor (EGF), on TGF-β1 expression in the bovine MEC lines, BME-UV1 and MAC-T. The model of apoptosis in bovine mammary gland in vitro was applied by reduction of fetal bovine serum (FBS) (from 10% to 2% or 0·5% FBS) in the cell environment to show the relationship between TGF-β1 expression and apoptosis in bovine MEC. RT-PCR, Western blot and laser scanning cytometry (LSC) were used for analysis of TGF-β1 transcript and protein level as well as apoptosis and cell cycle in examined MEC. In this model of apoptosis, FBS deficiency (mimicking the naturally occurring decline in the access of bioactive compounds and nutrients at the end of lactation and dry period) was associated with increased TGF-β1 expression at the level of transcript and protein, induction of apoptosis and inhibition of cell cycle. Exogenous TGF-β1, IGF-I, EGF and GH inhibited FBS-deficiency-stimulated TGF-β1 expression. The suppressive effect of GH was reversed when cells were maintained longer in FBS-deficient medium. In general, STS, E2 and P4 increased TGF-β1 expression. However, this effect was dependent on hormone concentration and cell line. BME-UV1 cells were much more responsive to the peptides, GH, STS, IGF-I and EGF, whereas MAC-T cells were more responsive to the steroid sex hormones: E2 and P4.
Evaluation of different preservation techniques on the storage potential of Kefir grains
Authors: Witthuhn R Corli , Cilliers Annamie , Britz Trevor J
Published: January 2005

Kefir is an acidic, mildly alcoholic dairy beverage produced by the fermentation of milk with a grain-like starter culture (Koroleva, 1988). These grains usually contain a relatively stable and specific balance of microbes that exist in a complex symbiotic relationship (Obermann & Libudzisz, 1998; Witthuhn et al. 2004). The different groups of microbes present in the grains are active at different stages of the fermentation (Koroleva, 1982). The lactococci, including Lactococcus lactis subsp. lactis, Lc. lactis subsp. cremoris and Lc. lactis subsp. diacetilactis provide rapid acid development during the first hours of the fermentation (Litopoulou-Tzanetaki & Tzanetakis, 2000). As the acidity of the milk increases it provides favourable conditions for the growth of the lactobacilli (Rea et al. 1996). The yeasts, acetic acid bacteria and the aroma-producing microbes, mainly leuconostocs, have a much slower growth rate than the lactic acid producers, resulting in the slow production of the aroma compounds and the gradual increase in the concentration of these substances in the later stages of the fermentation (Koroleva, 1982).
The Intensification of Corruption in China
Authors: Wederman Andrew
Published: January 2005

Although most analysts agree that corruption has worsened since the advent of reform, this article argues that whereas the first stages of reform witnessed a quantitative increase in corruption, during the 1990s corruption underwent a qualitative change as high-level, high-stakes corruption increased more rapidly than other forms of official malfeasance. Drawing together data from the Party discipline inspection system, the state supervisory system and the judicial procuratorial system, the article examines in detail trends in forms of official misconduct broadly defined and corruption more narrowly defined as the use of public authority for private gain, charting not only overall trends in malfeasance and corruption but also trends in the number of “major cases,” cases involving senior cadres, and the amounts of corrupt monies. Its finding that corruption has intensified raises important questions about the efficacy of enforcement, the link between the deepening of reform and the intensification of corruption, and the economic consequences of intensification.
China's “City System” in Flux: Explaining Post-Mao Administrative Changes
Authors: Chung Jae Ho , Lam Tao-chiu
Published: January 2005

China's urbanization has accelerated during the era of reform. While there has been real progress in urbanization, the process has also been skewed by several administrative measures designed to foster urbanization and economic growth. According to a popular view, as many as 70 per cent of China's administrative jurisdictions now come under the rule of urban governments. This must be an exaggeration given that many parts of China are still essentially rural. This article examines three measures – turning prefectures into cities (di gai shi), turning counties into cities (xian gai shi), and turning cities and counties into urban districts (xian shi gai qu) – that have contributed to “inflated urbanization.” Five propositions – budgetary, urbanization, regulatory, organizational streamlining and policy incentive – are discussed to see if the three measures have either originated from or have affected them. We find that while the regulatory observation is relevant only for the measure of xian shi gai qu, the other four propositions are useful, though to varying degrees, for understanding the logic of the changing “city system” in the past two decades.
The Shanghai Co-operation Organization: China's Changing Influence in Central Asia
Authors: Chung Chien-peng
Published: January 2005

China, Russia and the Central Asian states of Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan formed the Shanghai Co-operation Organization (SCO) in 2001. China's backing for an SCO charter, permanent secretariat and anti-terrorism centre for the past three years reflects its desire to strengthen the SCO in countering United States influence in Central Asia. Diplomatically, China fears that the American presence means that regional states will be less accommodating to China's political demands. Economically, China worries that the United States' support for American petroleum companies will compromise Chinese efforts to wrest concessions from Central Asian governments. Security-wise, with bases close to China's western borders, Washington can assist Beijing in flushing out Xinjiang separatists operating in Central Asia, or put military pressure on China, should it be perceived as a threat. The American presence and resurgent Russian involvement in Central Asia seem to have put China's influence in the region on the defensive.
Spreading Telecommunications to Developing Areas in China: Telephones, the Internet and the Digital Divide
Authors: Harwit Eric
Published: January 2005

China's overall telecommunications development during the past 20 years has been remarkable, and in 2004 the nation ranks first in the world in numbers of both mobile and fixed-line telephones, and second in the number of internet users. However, the recent growth has left the country's vast population with an internal communications and digital divide among “haves” and “have nots,” with citizen access mainly separated along economic and regional lines. This article assesses the growth of the communications divide, reasons for its occurrence, and ways political, economic and technological forces are shaping the spread of China's telecommunications tools.
Nested Pyramid Structures: Political Parties in Taiwanese Elections
Authors: Mattlin Mikael
Published: January 2005

The nature of the political party in Taiwan has been insufficiently problematized in recent writings on the island's elections. Based on field research this article argues that the informal structure of political support in Taiwan takes the shape of nested pyramid structures, built of successive dyadic support relations between politician and supporter and two politicians at different hierarchical levels, culminating in a handful of top political leaders. The political party is only the widest kind of support network, and in lower-level elections not the central agent. The dyads in Taiwan politics differ from traditional patron–client relations in being more dynamic, equal and voluntary. This informal political structure coupled with generally weak party loyalty and large benefits of incumbency produces pervasive party instability and subsequent election instability at higher election levels. The number of top political leaders and relations between them are critical in structuring the party scene.
Development of Land Rental Markets in Rural Zhejiang: Growth of Off-farm Jobs and Institution Building
Authors: Zhang Qian Forrest , Qingguo Ma , Xu Xu
Published: January 2005

We employ survey data collected in 2001 in Zhejiang province to investigate patterns and determinants of land market development. Previous studies have noted the correlation between growth of off-farm jobs and rental-market development at the aggregate level, but failed empirically to demonstrate mechanisms at the disaggregate level. Our analyses find concrete evidence at the household level connecting developments in labour and land markets. Growth in off-farm jobs allow rural households to transfer labour out of farming and prompt them to relinquish land rights, generating a supply of land that drives rental activities. We also go beyond interactions between factor markets and examine how local institution building promotes rental-market development. Institutions that either lower transaction costs or secure property rights are found to be crucial in explaining cross-regional variations in rental-market development. Finally, the rise of land rental markets also highlights the role of collective ownership in shaping rural development trajectory.
Only Hope: Coming of Age under China's One-Child Policy. By Vanessa L. Fong. [Stanford: Stanford University Press, 2004. 242 pp. £29.95. ISBN 0-8047-4961-2.]
Authors: Kallgren Joyce K.
Published: January 2005

This is an ethnographic study, conducted in Dalian between June 1997 and 2002, of a sample of singleton urban youths and their families. The author interviewed high school boys and girls and their families about their hopes for college and the elite jobs expected upon graduation. Given that Fong (now an assistant professor in the Harvard School of Education) was then a graduate student at Harvard, home of some of the most respected anthropology and sociology faculty whose careers began with survey projects such as this, there are understandingly high hopes for this book (the revised product of her dissertation). Although the footprint of the dissertation (in style and, to some extent, in theory) remains to distract the China specialist occasionally, the book is fascinating and, as book editors often say, “a good read.”

Over the last 20 years, there have been a number of studies by Chinese and foreign scholars on the establishment, provision, effectiveness and consequences of the so-called single child family (SCF) policy. This controversial policy, subject to different interpretations and more effective in urban China than in rural areas, seems well established. The generation of young people now coming of age includes the so-called singletons. Fong has contributed to our understanding of their situation by her use of the term “only hope,” by which she means these children are the only hope for a growing number of aging, city-dwelling parents, who are without jobs or welfare protection, and thus facing a bleak future.
Understanding the Political Culture of Hong Kong: The Paradox of Activism and Depoliticization. By Lamwai-Man. [Armonk, NY and London: M.E. Sharpe, 2004. xi +291 pp. $72.95. ISBN: 0-7656-1313-1.]
Authors: Ku Agnes S.
Published: January 2005

Buttressed by local scholarship, the conventional understanding of Hong Kong's political culture has long dwelt on the notions of apathy and indifference. Understanding the Political Culture of Hong Kong advances an interesting and provocative thesis to refute the conventional claim by taking readers through a historical journey of Hong Kong's major conflict events between 1949 and 1979. The author ambitiously seeks to engage in a critical evaluation of the conventional theses, especially that by Siu-kai Lau in the 1980s. Lau's idea of utilitarian familism, which is much cited in Hong Kong studies, provides an explanation of political apathy that locates the causes in the wider culture as well as in weak state-society relations. Questioning Lau's thesis on strong methodological, conceptual and empirical grounds, the author aims to present an alternative reading of Hong Kong politics, which she captures well in the subtitle: the paradox of activism and depoliticization.

Contrary to Lau, the author argues that political participation was neither minimal nor simply utilitarian. She broadens the conception of political participation to include political acts targeted at the local government, the Chinese government and private institutions; discursive activities through the press; and politically relevant activities via social organizations and social movements. Using a multiple-case interpretive approach, she draws on 13 events as case studies and analyses them in terms of their scale, intensity, publicity, significance and ideological claims. The author maintains that all of the events were “impressive” and were “part of larger movements that persisted over a number of decades and that were sustained by the particular nature of society and politics at that time” (p. 229). These testify to the existence of significant levels of political activism. Adding a twist to her argument, the author further maintains that a culture of depoliticization existed side by side with political activism, which functioned to check left-wing activism in the context of Cold War and Chinese politics.
Catastrophic ozone loss during passage of the Solar system through an interstellar cloud
Authors: Pavlov Alexander A. , Pavlov Anatoli K. , Mills Michael J. , Ostryakov Valery M. , Vasilyev Gennadiy I. , Toon Owen B.
Published: January 2005

When Solar system passes through moderately dense interstellar clouds, Earth experiences a dramatic increase in the flux of the anomalous component of cosmic rays (ACRs) along with an increased flux of galactic cosmic rays. ACR flux across the Earth's orbit lasts as long as it takes to cross a moderately dense interstellar cloud, about 1 Myr years. A period of ∼1 Myr is long enough for Earth to experience at least one magnetic reversal allowing penetration of the cosmic rays deep into the atmosphere even at low latitudes. Such increased cosmic ray fluxes would enhance the abundance of stratospheric NOx ∼100 times between 20–40 km, which in turn would decrease the ozone column globally by at least 40% and in the polar regions up to 80%. Such ozone loss would last for the duration of the magnetic reversal and could trigger global extinctions.
Intercontinental air pollution transport from North America to Europe: Experimental evidence from airborne measurements and surface observations
Authors: Huntrieser H. , Heland J. , Schlager H. , Forster C. , Stohl A. , Aufmhoff H. , Arnold F. , Scheel H. E. , Campana M. , Gilge S. , Eixmann R. , Cooper O.
Published: January 2005

During the airborne CONTRACE field experiment carried out in November 2001 a number of polluted layers of North American (NA) origin were observed in the free troposphere over Europe. For the first time, forecasts from a Lagrangian particle dispersion model were used to predict the NA pollution events and to direct a research aircraft very precisely into these polluted layers above Europe. Two of the NA pollution events are investigated here: one in detail (case 19 November) and a second more briefly (case 22 November). An exceptional result was that the first pollution plume could be traced with the model and trace gas measurements (airborne and surface) for a period of one week, from the source region over the eastern United States to its decay over the Alps. On 14–15 November a warm conveyor belt lifted the leading edge of the pollution plume over the eastern United States to the mid troposphere where it remained during the transport over the Atlantic. On 19 November the plume was intersected with the research aircraft over Scandinavia at an altitude between 2 and 4 km. Elevated CO (170), O3 (53), NOy (1.1), acetone (5.0), and SO2 (2.6) mixing ratios (nmol mol−1) were measured. A positive O3‐CO correlation was observed in the plume. The observations indicate that the enhanced levels of ozone were already produced near the source region over the eastern United States and not during the transit. In the next days one branch of the plume then turned to the south and descended to ground level over the Alpine region. Elevated O3 (54 nmol mol−1) and CO (168 nmol mol−1) were observed at the mountain site Zugspitze (southern Germany) during two days. At the Arosa Alpine site in Switzerland the highest daily ozone means of November 2001 were observed during this event.
Microscopy and mineralogy of airborne particles collected during severe dust storm episodes in Beijing, China
Authors: Shi Zongbo , Shao Longyi , Jones T. P. , Lu Senlin
Published: January 2005

Asia dust storm (ADS) samples were collected during two severe dust storm episodes in Beijing, China. High‐resolution field emission scanning electron microscopy (FESEM) and environmental scanning electron microscopy‐energy dispersive X‐ray detector (ESEM‐EDX) coupled with an image analysis system were used to study the morphology, chemical compositions, and number‐size distributions of ADS particles. FESEM analysis indicated that Beijing ADS samples were mainly composed of irregularly shaped mineral particles. More than 50% of the ADS particles were larger than 1 μm, measured as equivalent spherical diameter (ESD). Image analysis showed that when the dust storm episodes ended in Beijing, the number of anthropogenic particles, such as soot aggregates and coal fly ash, in the samples increased, and the number of mineral particles decreased. Analysis of individual ADS particles showed that about one fifth of all the particles were mineral aggregates, and at least one fourth of the particles contained sulfur. X‐ray diffraction (XRD) was used to quantify the phase and the clay mineral compositions of ADS samples. Phases in the ADS sample collected during the 20 March 2002 dust storm episode included clay minerals, noncrystalline materials, quartz, calcite, plagioclase, potassium feldspar, pyrite, hornblende, and gypsum in descending order. Clay minerals were mainly illite/smectite mixed layers (78%), followed by illite (9%), kaolinite (6%), and chlorite (7%). Particulate matter (PM) less than 10 μm were enriched with clay minerals and deficient with quartz by mass compared with the total suspended particulates collected during an ADS episode. The PM less than 10 μm collected during the two severe dust storm episodes was characterized by the absence of dolomite, high quartz/clay ratio, and dominance of illite/smectite mixed layers in clay minerals.
Molecules in high spin states III: The millimeter/submillimeter-wave spectrum of the MnCl radical (X 7Σ+)
Authors: Halfen D. T. , Ziurys L. M.
Published: January 2005

The pure rotational spectrum of the MnCl radical (X 7Σ+) has been recorded in the range 141–535 GHz using millimeter–submillimeter direct absorption spectroscopy. This work is the first time the molecule has been studied with rotational resolution in its ground electronic state. MnCl was synthesized by the reaction of manganese vapor, produced in a Broida-type oven, with Cl2. Transitions of both chlorine isotopomers were measured, as well as lines originating in several vibrationally excited states. The presence of several spin components and manganese hyperfine interactions resulted in quite complex spectra, consisting of multiple blended features. Because 42 rotational transitions were measured for Mn35Cl over a wide range of frequencies with high signal-to-noise, a very accurate set of rotational, fine structure, and hyperfine constants could be determined with the aid of spectral simulations. Spectroscopic constants were also determined for Mn37Cl and several vibrationally excited states. The values of the spin-rotation and spin–spin parameters were found to be relatively small (γ=11.2658 MHz and λ=1113.10 MHz for Mn35Cl); in the case of λ, excited electronic states contributing to the second-order spin–orbit interaction may be canceling each other. The Fermi contact hyperfine term was found to be large in manganese chloride with bF(Mn35Cl)=397.71 MHz, a result of the manganese 4s character mixing into the 12σ orbital. This orbital is spσ hybridized, and contains some Mn 4pσ character, as well. Hence, it also contributes to the dipolar constant c, which is small and positive for this radical (c=32.35 MHz for Mn35Cl). The hyperfine parameters in MnCl are similar to those of MnH and MnF, suggesting that the bonding in these three molecules is comparable.
Measurement of vibrational, gas, and rotational temperatures of H2 (X1Σg+) in radio frequency inductive discharge plasma by multiplex coherent anti-Stokes Raman scattering spectroscopy technique
Authors: Shakhatov V. A. , De Pascale O. , Capitelli M. , Hassouni K. , Lombardi G. , Gicquel A.
Published: January 2005

Translational, rotational, and vibrational temperatures of H2 in radio frequency inductive discharge plasmas at pressures and power release ranges, respectively, of 0.5–8 torr and 0.5–2W∕cm3 have been measured by using multiplex coherent anti-Stokes Raman scattering (CARS) spectroscopy. Computational codes have been developed to determine the rotational and vibrational temperatures and to analyze H2 CARS spectrum for nonequilibrium conditions. The results show a decrease of the vibrational temperature from 4250 to 2800 K by increasing the pressure from 0.5 to 8 torr and a corresponding increase of the rotational temperature from 525 to 750 K.
Ab initio potential energy surfaces, total absorption cross sections, and product quantum state distributions for the low-lying electronic states of N2O
Authors: Daud Mohammad Noh , Balint-Kurti Gabriel G. , Brown Alex
Published: January 2005

Adiabatic potential energy surfaces for the six lowest singlet electronic states of N2O (X 1A′, 2 1A′, 3 1A′, 1 1A″, 2 1A″ and 3 1A″) have been computed using an ab initio multireference configuration interaction (MRCI) method and a large orbital basis set (aug-cc-pVQZ). The potential energy surfaces display several symmetry related and some nonsymmetry related conical intersections. Total photodissociation cross sections and product rotational state distributions have been calculated for the first ultraviolet absorption band of the system using the adiabatic ab initio potential energy and transition dipole moment surfaces corresponding to the lowest three excited electronic states. In the Franck–Condon region the potential energy curves corresponding to these three states lie very close in energy and they all contribute to the absorption cross section in the first ultraviolet band. The total angular momentum is treated correctly in both the initial and final states. The total photodissociation spectra and product rotational distributions are determined for N2O initially in its ground vibrational state (0,0,0) and in the vibrationally excited (0,1,0) (bending) state. The resulting total absorption spectra are in good quantitative agreement with the experimental results over the region of the first ultraviolet absorption band, from 150 to 220 nm. All of the lowest three electronically excited states [1Σ−(1 1A″), Δ1(2 1A′), and Δ1(2 1A″)] have zero transition dipole moments from the ground state [1Σ+(1 1A′)] in its equilibrium linear configuration. The absorption becomes possible only through the bending motion of the molecule. The Δ1(2 1A′)←X 1Σ+(1A′) absorption dominates the absorption cross section with absorption to the other two electronic states contributing to the shape and diffuse structure of the band. It is suggested that absorption to the bound Δ1(2 1A″) state makes an important contribution to the experimentally observed diffuse structure in the first ultraviolet absorption band. The predicted product rotational quantum state distribution at 203 nm agrees well with experimental observations.
Intramolecular fluorescence quenching in luminescent copolymers containing fluorenone and fluorene units: A direct measurement of intrachain exciton hopping rate
Authors: Dias Fernando B. , Maiti Manisankar , Hintschich Susanne I. , Monkman Andrew P.
Published: January 2005

The quenching process of fluorescence emission in polyfluorene (PF) due to the presence of intramolecular 9-fluorenone (9FL) moieties is studied in dilute toluene solution as a function of 9FL content in eight copolymers containing both fluorene and fluorenone units (PF/FLx). The absorption spectrum of PF/FLx copolymers clearly shows a new absorption band, redshifted relatively to the PF and 9-fluorenone absorption, which increases in intensity when the fluorenone fraction increases and also decreases with solvent polarity. Fluorescence emission spectra of PF/FLx show that this redshifted and unstructured emission does not coincide with the 9-fluorenone emission and, with increasing solvent polarity, it further redshifts and decreases in intensity. An isoemissive point is clearly observed on the fluorescence emission spectra of PF/FLx as a function of fluorenone content, showing that the new emission band is formed at the expense of PF. We propose the formation of an intramolecular charge transfer complex (ICTC) between PF units and 9-fluorenone to explain the appearance of the new emission band. Global analysis of time resolved fluorescence decays collected at 415 nm (PF emission) and 580 nm (the ICTC emission) show that three exponentials are generally needed to achieve excellent fits. Two of the components (420 ps and 6.5 ns) are independent of 9-fluorenone fraction. A further fast component is strongly dependent on fluorenone fraction and ranges between 280 and 70 ps. This component appears as a decay time at 415 nm and as a rise time at 580 nm and is ascribed to the migration of exciton to quenching sites (formation of intramolecular CT complex or exciton ionization at CT complex). A kinetic mechanism involving three different kinetic species, quenched PF units kinetically coupled with the ICTC complex, and unquenched PF units is proposed to explain the experimental data and the quenching rate constant is obtained, k1≅1011 s−1. This is an experimental measurement of the intrachain exciton hopping rate.
Femtosecond dynamics of Cu(H2O)2
Authors: Taylor Mark S. , Barbera Jack , Schulz Claus-Peter , Muntean Felician , McCoy Anne B. , Lineberger W. Carl
Published: January 2005

The ultrafast relaxation dynamics of Cu(H2O)2 is investigated using femtosecond photodetachment-photoionization spectroscopy. In addition, stationary points on the Cu(H2O)2 anion, neutral, and cation potential energy surfaces are characterized by ab initio electronic structure calculations. Electron photodetachment from Cu−(H2O)2 initiates the dynamics on the ground-state potential energy surface of neutral Cu(H2O)2. The resulting Cu(H2O)2 complexes experience large-amplitude H2O reorientation and dissociation. The time evolution of the Cu(H2O)2 fragmentation products is monitored by time-resolved resonant multiphoton ionization. The parent ion, Cu+(H2O)2, is not detected above background levels. The rise to a maximum of the Cu+ signal from Cu−(H2O)2, and the decay of the Cu+(H2O) signal from Cu−(H2O)2 have similar τ≈10 ps time dependences to the corresponding signals from Cu−(H2O), but display clear differences at very short and long times. The experimental observations can be understood in terms of the following picture. Prompt dissociation of H2O from nascent Cu(H2O)2 gives rise to a vibrationally excited Cu(H2O) complex, which dissociates to Cu+H2O due to coupling of H2O internal rotation to the dissociation coordinate. This prompt dissociation removes all intra-H2O vibrational excitation from the intermediate Cu(H2O) fragment, which quenches the long time vibrational predissociation to Cu+H2O previously observed in analogous experiments on Cu−(H2O).
Local hydrogen bonding dynamics and collective reorganization in water: Ultrafast infrared spectroscopy of HOD/D2O
Authors: Fecko Christopher J. , Loparo Joseph J. , Roberts Sean T. , Tokmakoff Andrei
Published: January 2005

We present an investigation into hydrogen bonding dynamics and kinetics in water using femtosecond infrared spectroscopy of the OH stretching vibration of HOD in D2O. Infrared vibrational echo peak shift and polarization-selective pump-probe experiments were performed with mid-IR pulses short enough to capture all relevant dynamical processes. The experiments are self-consistently analyzed with a nonlinear response function expressed in terms of three dynamical parameters for the OH stretching vibration: the frequency correlation function, the lifetime, and the second Legendre polynomial dipole reorientation correlation function. It also accounts for vibrational-relaxation-induced excitation of intermolecular motion that appears as heating. The long time, picosecond behavior is consistent with previous work, but new dynamics are revealed on the sub-200 fs time scale. The frequency correlation function is characterized by a 50 fs decay and 180 fs beat associated with underdamped intermolecular vibrations of hydrogen bonding partners prior to 1.4 ps exponential relaxation. The reorientational correlation function observes a 50 fs librational decay prior to 3 ps diffusive reorientation. Both of these correlation functions compare favorably with the predictions from classical molecular dynamics simulations. The time-dependent behavior can be separated into short and long time scales by the 340 fs correlation time for OH frequency shifts. The fast time scales arise from dynamics that are mainly local: fluctuations in hydrogen bond distances and angles within relatively fixed intermolecular configurations. On time scales longer than the correlation time, dephasing and reorientations reflect collective reorganization of the liquid structure. Since the OH transition frequency and dipole are only weakly sensitive to these collective coordinates, this is a kinetic regime which gives an effective rate for exchange of intermolecular structures.
Response to “Comment on ‘A centroid molecular dynamics study of liquid para-hydrogen and ortho-deuterium’ ” [J. Chem. Phys. 122, 057101 (2005)]
Authors: Voth Gregory A. , Hone Tyler D.
Published: January 2005

The issue of the proper classical limit for approximate quantum dynamical methods is discussed, especially as it applies to liquid para-hydrogen. The conclusion is that a logical dilemma arises, in which the quantum system is in one thermodynamic state but the classical system for the same volume is in a different thermodynamic state. This dilemma also points to the likelihood that a certain class of approximate quantum dynamical methods, in which the initial conditions are weighted by a quantum distribution function but the dynamics are then run with classical trajectories, will contain a systematic error in the dynamical results for such systems.
Chemisorption sites of CO on small gold clusters and transitions from chemisorption to physisorption
Authors: Zhai Hua-Jin , Wang Lai-Sheng
Published: January 2005

Gold clusters adsorbed with CO, Aum(CO)n− (m=2–5; n=0–7), were studied by photoelectron spectroscopy (PES). The first few CO adsorptions were observed to induce significant redshifts to the PES spectra relative to pure gold clusters. For each Au cluster, a critical CO number (nc) was observed, beyond which the PES spectra of Aum(CO)n− change very little with increasing n. nc was shown to correspond exactly to the available low coordination apex sites in each Au cluster. CO first chemisorbs to these sites and additional CO then only physisorbs to the chemisorption-sautrated Aum(CO)n− complexes.
Combinatorial theory of Macdonald polynomials I: Proof of Haglund's formula
Authors: Haglund J. , Haiman M. , Loehr N.
Published: January 2005

Haglund recently proposed a combinatorial interpretation of the modified Macdonald polynomialsH̃μ. We give a combinatorial proof of this conjecture, which establishes the existence and integrality ofH̃μ. As corollaries, we obtain the cocharge formula of Lascoux and Schützenberger for Hall–Littlewood polynomials, a formula of Sahi and Knop for Jack's symmetric functions, a generalization of this result to the integral Macdonald polynomialsJμ, a formula forH̃μin terms of Lascoux–Leclerc–Thibon polynomials, and combinatorial expressions for the Kostka–Macdonald coefficientsK̃λ,μwhen μ is a two-column shape.