bluuebunny/crossref_metadata_2025 huggingface dataset:
RNase J is involved in the 5′‐end maturation of 16S rRNA and 23S rRNA in Sinorhizobium meliloti
Authors: Madhugiri Ramakanth , Evguenieva-Hackenberg Elena
Published: June 2009

Sinorhizobium meliloti harbours genes encoding orthologs of ribonuclease (RNase) E and RNase J, the principle endoribonucleases in Escherichia coli and Bacillus subtilis, respectively. To analyse the role of RNase J in S. meliloti, RNA from a mutant with miniTn5‐insertion in the RNase J‐encoding gene was compared to the wild‐type and a difference in the length of the 5.8S‐like ribosomal RNA (rRNA) was observed. Complementation of the mutant, Northern blotting and primer extension revealed that RNase J is necessary for the 5′‐end maturation of 16S rRNA and of the two 23S rRNA fragments, but not of 5S rRNA.
Temperature‐dependent hyper‐activation of monoglucosyldiacylglycerol synthase is post‐translationally regulated in Synechocystis sp. PCC 6803
Authors: Shimojima Mie , Tsuchiya Mami , Ohta Hiroyuki
Published: June 2009

The mechanism of monoglucosyldiacylglycerol (MGlcDG) increase following heat shock in Synechocystis sp. PCC 6803 was examined by measuring MGlcDG synthase (Sll1377) activity. Temperature‐dependent activation of Sll1377 was observed in the membrane fraction of Synechocystis sp. PCC 6803, whereas the Sll1377 protein level remained unchanged, suggesting that the activity is post‐translationally regulated without covalent modification of Sll1377 by soluble enzymes. Four individual mutations introduced into recombinant Sll1377 (D147, D200, R329, and R331) significantly reduced the activity and blocked temperature‐dependent activation, suggesting that these amino acid residues are essential for Sll1377 activity at both normal growth temperature and the higher temperature.
Fifteen years after the International Conference on Population and Development: What have we achieved and how do we move forward?
Authors: Obaid Thoraya Ahmed
Published: June 2009

This article surveys the current situation and prospects for attaining the goals set by the International Conference on Population and Development (ICPD) held in 1994, and the health‐related Millennium Development Goals (MDGs), set in 2000. Encouraging changes in the policy environment are highlighted, but the available resources do not yet match needs. Global maternal mortality figures, at over 500 000 a year, have not changed since 1990, and morbidity is about 20 million. Some countries have made progress with low‐cost, high‐yield interventions such as family planning, skilled birth attendants, access to emergency obstetric and neonatal care, management of sexually transmitted infections, and HIV prevention. However, progress in many low‐income countries has been slow, and few are on track to meet the goals. There are wide inequities in care among and within countries. Suggestions for priority attention are offered, such as a “continuum of care” approach, integrated services, and comprehensive policies on human resources for health.
A multidisciplinary approach to improving women's health in semi‐urban Ecuador
Authors: Yancon Andrea R. , Kelly Sean G. , Valsangkar Bina , Iyengar Preetha , Malani Preeti N.
Published: June 2009

Objective

To examine women's reasons for seeking care at The Quito Project (TQP), a student‐led organization that aims to improve the health, education, and well‐being of a semi‐urban community in Quito, Ecuador, and to explore the need for additional preventative interventions.

Methods

An oral survey was administered to 86 adult patients in 2008. We also completed a chart review to evaluate patient demographics and medical conditions.

Results

Sixty‐three (73.3%) survey respondents were female. Nearly three‐quarters of the women reported an income below the minimum wage; 60% reported that the cost of medical care posed a burden. Fifty‐two percent sought care at TQP because the services were free. Additionally, 77% of women reported going to the doctor only when ill and did not access preventative services.

Conclusions

By offering medical, dental, and tutoring services, along with preventative health workshops, TQP addresses established barriers to achieving adequate women's health. Survey results have reinforced TQP's focus on prevention.
Effect of short‐term maternal fasting in the third trimester on uterine, umbilical, and fetal middle cerebral artery Doppler indices
Authors: Abd‐El‐Aal Diaa‐Eldeen M. , Shahin Ahmed Y. , Hamed Hossam O.
Published: June 2009

Objective

To assess the effect of short‐term maternal fasting on uterine, umbilical, and middle cerebral artery Doppler indices, and on maternal serum glucose levels and fetal behavior.

Methods

Maternal serum glucose levels, fetal biophysical profiles, and uterine, umbilical, and middle cerebral artery Doppler indices were assessed in 110 healthy women in the third trimester of pregnancy after fasting for 10–12 hours and 2 hours after a balanced meal.

Results

Maternal serum glucose levels, nonstress test results, fetal breathing movements, and biophysical profile improved after a meal compared with after fasting for 10–12 hours. Uterine, umbilical, and middle cerebral artery Doppler indices were not significantly different after fasting and after a meal.

Conclusion

Short‐term maternal fasting during the third trimester of pregnancy has no effect on uterine, umbilical, or fetal cerebral artery Doppler indices, and has a transient but significant effect on maternal serum glucose levels and fetal behavior.
Affective forecasting and self‐control: Why anticipating pride wins over anticipating shame in a self‐regulation context
Authors: Patrick Vanessa M. , Chun HaeEun Helen , Macinnis Deborah J.
Published: June 2009

We demonstrate that anticipating pride from resisting temptation facilitates self‐control due to an enhanced focus on the self while anticipating shame from giving in to temptation results in self‐control failure due to a focus on the tempting stimulus. In two studies we demonstrate the effects of anticipating pride (vs. shame) on self‐control thoughts and behavior over time (Studies 1 and 2) and illustrate the process mechanism of self vs. stimulus focus underlying the differential influence of these emotions on self‐control (Study 2). We present thought protocols, behavioral data (quantity consumed) and observational data (number/size of bites) to support our hypotheses.
Who I am and how I think: The impact of self‐construal on the roles of internal and external reference prices in price evaluations
Authors: Chen Cathy Yi
Published: June 2009

Drawing from self‐construal studies on cognitive styles as well as reference price literature, this research investigates the impact of independent versus interdependent self‐construal on consumers' use of internal reference prices (IRPs) and external reference prices (ERPs) during price evaluations. Three experiments reveal that IRPs have a larger impact on price evaluations for participants who are primed with an independent (vs. interdependent) self‐construal, whereas ERPs have a larger impact for participants who are primed with an interdependent (vs. independent) self‐construal. The differential impact of self‐construal on the use of IRPs and ERPs seems to be mediated by a generalized, perceived sense of connectedness/separateness. Implications on reference price research, self‐construal and cognitive styles are discussed.
Comparison between the analgesic effects of morphine and tramadol delivered epidurally in cats receiving a standardized noxious stimulation
Authors: Castro Douglas S. , Silva Marta F.A. , Shih Andre C. , Motta Pedro P.A. , Pires Marcos V.M. , Scherer Paulo O.
Published: June 2009

This study compared the analgesic effects of epidural tramadol versus morphine in six healthy cats. Under general anesthesia, each cat received an epidural injection of saline 0.22 ml/kg (control treatment, CT), tramadol 1 mg/kg (tramadol treatment, TT), or morphine 0.1 mg/kg (morphine treatment, MT). After cats had recovered from anesthesia a simple descriptive scale (SDS), visual analog scale (VAS) and physiological parameters (respiratory and heart rate) were used to assess analgesia level to a noxious stimulus (base of the tail skin fold clamping) at 1, 2, 3, 4, 6, 8, 10, and 12 h post-epidural. Group TT had a higher SDS and VAS score when compared to MT at 8, 10 and 12 h post-epidural. CT had higher SDS and VAS score at all time points when compared to TT and MT. In conclusion both morphine and tramadol provided analgesia in this model for the first 6 h; with epidural morphine resulting in longer lasting analgesia when compared to tramadol.
Concentrated supply chain membership and financial performance: Chain‐ and firm‐level perspectives
Authors: Lanier Danny , Wempe William F. , Zacharia Zach G.
Published: June 2009

This study reports evidence that concentrated 3‐firm supply chains achieve superior financial performance, and that supply chains’ financial performance varies systematically with measures of chain concentration and chain duration. Results from firm‐level analyses suggest that the profitability benefits of supply chain relationships are captured predominantly by downstream chain members, whereas cash cycle benefits are realized throughout the supply chain. Firm‐level tests also reveal that chain members’ financial performance varies systematically with measures of downstream bargaining power, downstream relationship duration, and degree of supply consolidation. The study's chain‐ and firm‐level analyses employ data extracted from sample firms’ publicly available financial reports, including their major customer disclosures under Statement of Financial Accounting Standards Nos. 131 (1997) and 14 (1976).
Electronic limit order book and order submission choice around macroeconomic news
Authors: Erenburg Grigori , Lasser Dennis
Published: June 2009

We investigate the dynamics of the displayed part of the Island ECN limit order book for the equity‐index‐linked securities market around macroeconomic news releases. Our results indicate that the quality of the electronic market, measured by spread and depth, deteriorates during the releases. Furthermore, they show that traders appear to switch to more aggressive strategies as early as 3 min before an announcement and are most aggressive within the first minute after the announcement. Also, there is a noticeable difference in the response of the limit order book to the macroeconomic news during pre‐market hours relative to regular trading hours.
Palynological evidence for climatic and oceanic variability off NW Africa during the late Holocene
Authors: Bouimetarhan Ilham , Dupont Lydie , Schefuß Enno , Mollenhauer Gesine , Mulitza Stefan , Zonneveld Karin
Published: June 2009

Pollen and organic-walled dinoflagellate cyst assemblages from core GeoB 9503-5 retrieved from the mud-belt (∼ 50 m water depth) off the Senegal River mouth have been analyzed to reconstruct short-term palaeoceanographic and palaeoenvironmental changes in subtropical NW Africa during the time interval from ca. 4200 to 1200 cal yr BP. Our study emphasizes significant coeval changes in continental and oceanic environments in and off Senegal and shows that initial dry conditions were followed by a strong and rapid increase in humidity between ca. 2900 and 2500 cal yr BP. After ca. 2500 cal yr BP, the environment slowly became drier again as indicated by slight increases in Sahelian savannah and desert elements in the pollen record. Around ca. 2200 cal yr BP, this relatively dry period ended with periodic pulses of high terrigenous contributions and strong fluctuations in fern spore and river plume dinoflagellate cyst percentages as well as in the fluxes of pollen, dinoflagellate cysts, fresh-water algae and plant cuticles, suggesting “episodic flash flood” events of the Senegal River. The driest phase developed after about 2100 cal yr BP.
The effect of offering concentrate supplement to twin- and triplet-bearing ewes grazing a 60 mm herbage sward height on lamb birth weight, heat production and post-natal growth
Authors: KERSLAKE J. I. , KENYON P. R. , STAFFORD K. J. , MORRIS S. T. , MOREL P. C. H.
Published: June 2009

The current study investigated the effect of offering concentrate supplement to ewes in late pregnancy on twin- and triplet-born lamb heat production at 24–36 h old and performance from birth until lactation day 94 (L94). Twin- (n=40) and triplet-bearing (n=28) ewes were grazed on a 60 mm sward height from day 70 of pregnancy (P70) until L94. From P100, half of the ewes from each litter size were offered 400 g/ewe/day of concentrate sheep pellets. Ewe liveweight and body condition were recorded on P50, 100, 130, 135 and 140. Ewe blood samples were also collected on P130, 135 and 140, and ewe herbage intake was estimated from P133–136 using the n-alkane method. Lamb measurements included liveweight and body size at birth, production of heat using indirect open-circuit calorimetry at 24–36 h old and liveweight at L94. Blood samples were also collected from lambs at 24–36 h old and directly before and after calorimetry measurements. While estimates of ewe herbage intake suggested that substitution of herbage for concentrate did not occur, offering concentrate supplement failed to improve ewe liveweight gain, or birth weight of lambs. Offering concentrate supplement, however, did have a positive effect (P<0·05) on the maximal amount of heat a triplet-born lamb can produce on a per kg of body weight basis (concentrate 21±1·3 W/kg, non-concentrate 17±0·6 W/kg). It also had a positive effect (P<0·05) on lamb square-root-transformed plasma gamma-glutamyl transferase (GGT) concentrations, an indicator of colostrum uptake (concentrate 46±3·1 U/l, non-concentrate 38±2·9 U/l). Irrespective of lamb birth rank, offering concentrate supplement had a positive effect (P<0·01) on liveweight gain per day from birth until L94 (concentrate 261±5·7 g/day, non-concentrate 239±5·8 g/day), although there was no effect on the total weight of lamb reared/ewe. Supplementation with concentrate resulted in triplet-born lambs that produced more heat which may have positive effects on the ability of the newborn lamb to deal with cold stress and potentially its survival. Offering concentrate supplement also produced greater lamb growth in twin- and triplet-born lambs.
THE NEW ZEALAND BUSINESS CYCLE
Authors: Hall Viv B. , McDermott C. John
Published: June 2009

Our paper is in the spirit of Rex Bergstrom's interests and research in cyclical growth models and his meticulous attention to underlying data series. We develop a new quarterly real GDP series for post–World War II New Zealand, derive a new “benchmark” set of classical business cycle turning points, and establish nonparametric classical cycle characteristics. Markov-switching models, estimated by Gibbs-sampling methods, are used to derive mean growth rate and volatility regimes and to add to existing knowledge. The resulting properties, involving cycle asymmetries, volatility, diversity and duration dependence, and differing mean growth rate and volatility regimes, can be used to underpin a next generation of cyclical growth models for New Zealand, in the Bergstrom tradition.
APERIODIC DYNAMICS IN THE BERGSTROM/WYMER MODEL OF THE UNITED KINGDOM
Authors: Wymer Clifford R.
Published: June 2009

Lyapunov exponents may be used to provide information on attractors of nonlinear models and, if strange, their aperiodic dynamics, in much the same way as eigenvalues of a linear model. An advantage of calculating these from an estimated model, rather than calculating the largest ones from a time series, is that economic theory is used to help distinguish between deterministic and stochastic behavior. Estimates of the Bergstrom/Wymer model of the United Kingdom, and of some other models of a similar form, were unstable in a classical sense, to some extent being caused by policy parameters. The Lyapunov exponents show that this model, and variants of it, have strange attractors in the neighborhood of the estimated parameter values and hence are stable but with aperiodic oscillations.
On satellites in semi-abelian categories: Homology without projectives
Authors: GOEDECKE JULIA , VAN DER LINDEN TIM
Published: June 2009

Working in a semi-abelian context, we use Janelidze's theory of generalised satellites to study universal properties of the Everaert long exact homology sequence. This results in a new definition of homology which does not depend on the existence of projective objects. We explore the relations with other notions of homology, and thus prove a version of the higher Hopf formulae. We also work out some examples.
The Making of a New Working Class? A Study of Collective Actions of Migrant Workers in South China
Authors: Chan Chris King-Chi , Ngai Pun
Published: June 2009

In this study, we argue that the specific process of the proletarianization of Chinese migrant workers contributes to the recent rise of labour protests. Most of the collective actions involve workers' conflict with management at the point of production, while simultaneously entailing labour organizing in dormitories and communities. The type of living space, including workers' dormitories and migrant communities, facilitates collective actions organized not only on bases of locality, ethnicity, gender and peer alliance in a single workplace, but also on attempts to nurture workers' solidarity in a broader sense of a labour oppositional force moving beyond exclusive networks and ties, sometimes even involving cross-factory strike tactics. These collective actions are mostly interest-based, accompanied by a strong anti-foreign capital sentiment and a discourse of workers' rights. By providing detailed cases of workers' strikes in 2004 and 2007, we suggest that the making of a new working class is increasingly conscious of and participating in interest-based or class-oriented labour protests.
Post-Earthquake Relief and Reconstruction Efforts: The Emergence of Civil Society in China?
Authors: Teets Jessica C.
Published: June 2009

Many analysts contend that participation in the Sichuan earthquake relief efforts strengthened Chinese civil society. I examine these claims based on interviews with civil society organizations, academics and local officials in Sichuan, and argue that participation in relief efforts has strengthened civil society through increased capacity, publicity and interaction with local government. Conversely, relief efforts also reveal weaknesses in civil society and their governing institutions which inhibit further development, such as the trust and capacity deficit of these organizations. Participation in relief efforts served as a learning process whereby government, society and civil society groups learned how to work together effectively. However, in order to consolidate these gains and further strengthen civil society, there must be greater institutionalization of these groups' roles, increased capacity building, and greater trust between society, groups and the local state.
The Good Book and the Good Life: Bestselling Biographies in China's Economic Reform
Authors: Chua Huiching Emily
Published: June 2009

This article looks at currently bestselling biographies in urban China as popular histories of the national self from 1949 to the present. In their retrospective narrations of the Cultural Revolution and economic reform, they identify a reorientation of life away from ideological community and towards market rationality. I locate this shift also in the history of the publishing industry that produces them and analyse how publishing practices and values have changed from Mao to Jiang, to argue that a reconstitution of the “good” has been effected by the deployment of old rhetorical goals under structurally new conditions. Extended into the broader political arena, this suggests that institutional continuity in contemporary China masks a reconstitution of governance itself, from direct intervention and political control to administrative regulation and commercial competitiveness. Communist revolutionary ambitions are now redefined and fulfilled through economic success in commercial enterprise. Contrary to the prevalent notion that such couplings are contradictory and unsustainable, I argue that a mutually generative relationship currently exists between the two.
Planting Rice on the Roof of the UN Building: Analysing Taiwan's “Chinese” Techniques in Africa, 1961–present
Authors: Hsiao-pong Philip Liu
Published: June 2009

This article studies the development of the Republic of China's (Taiwan) agricultural aid projects to Africa from the 1960s to the present. Beginning with the Vanguard Project in 1961, Taiwan has sought to exchange its intensive rice cultivation techniques for international political recognition. The article looks at a variety of successful and failed assistance endeavours and analyses the motivation and processes behind this development assistance in the context of diverse African farming environments. Instead of insisting on its intensive farming culture, Taiwan has developed a sustainable aid mentality and now uses a hybrid approach that utilizes its cultivation expertise to complement the farming endowments of aid recipients.
High prevalence of HBV genotype D in Syria and the clinical characteristics of hepatitis B e antigen-negative chronic hepatitis B
Authors: ANTAKI N. , HAFFAR S. , ALI DEEB S. , ASSAAD F. , ABOU HARB R. , ZEIBANE N. , NASSERELDDINE M. , IBRAHIM N. , ALHAJ N. , JABBOUR E. , AARAJ R. , ANTAKI F. , KEBBEWAR K.
Published: June 2009

Hepatitis B virus (HBV) genotype D and hepatitis B e antigen (HBeAg) negative chronic hepatitis are the most prevalent in Mediterranean countries. No data have ever been published on their prevalence in Syria, a country of intermediate endemicity for HBV. The aims of the current study were to determine the HBV genotype distribution in Syria, the prevalence of HBeAg-positive and HBeAg-negative chronic hepatitis and to analyse the clinical characteristics of each group. A total of 220 patients were included. Ninety-seven percent of the patients were of genotype D, and 72% were HBeAg negative. The HBeAg-negative patients were older, had a lower viral load, had more cirrhosis and the mode of contamination was known less than for HBeAg-positive patients. These findings have major implications in understanding the natural history of the infection and are of great relevance in the choice of therapy.
The Linus Sequence
Authors: BALISTER PAUL , KALIKOW STEVE , SARKAR AMITES
Published: June 2009

Define the Linus sequence Ln for n ≥ 1 as a 0–1 sequence with L1 = 0, and Ln chosen so as to minimize the length of the longest immediately repeated block Ln−2r+1 ⋅⋅⋅ Ln−r = Ln−r+1 ⋅⋅⋅ Ln. Define the Sally sequence Sn as the length r of the longest repeated block that was avoided by the choice of Ln. We prove several results about these sequences, such as exponential decay of the frequency of highly periodic subwords of the Linus sequence, zero entropy of any stationary process obtained as a limit of word frequencies in the Linus sequence and infinite average value of the Sally sequence. In addition we make a number of conjectures about both sequences.
Hiding homelessness: ‘quality of life’ laws and the politics of development in American cities
Authors: Fang Anyu
Published: June 2009

An incredibly disturbing trend has surfaced recently in local American politics: cities are forbidding citizens from feeding homeless people. My focus is on how this has been created in tandem with shifts in public discourse. Although I recognise the similarities between the new ordinances and previous anti-homeless laws, I want to point to something new that is happening in the legal treatment of street people. City governments, somewhat dependent on the non-profit sector to give material aid while government services are cut, are now vigorously targeting charities/citizens. I will argue that this trend relates to a shift in the framing of the homeless issue – more specifically, a shift in the very definition of the homeless.
‘[It’s] like a rubber band.’ Assessing UNSCR 1325 as a gender mainstreaming process
Authors: Barrow Amy
Published: June 2009

The principal aim of gender mainstreaming is to achieve gender equality by implementing gender as a central component at all levels within the UN system. Previous work has focused on gender mainstreaming as an abstract concept, whereas this paper empirically examines efforts to implement UN Security Council Resolution 1325 (UNSCR 1325) and by doing so evaluates the process of mainstreaming. This paper suggests that gender mainstreaming has limited potential to achieve gender empowerment and equality. A lack of benchmarks and targets within UNSCR 1325 undermines the Security Council’s commitment to women’s experiences of armed conflict. Gender mainstreaming has largely not been implemented at a macro-level (within the UN), although at a micro-level, civil society organisations have made some attempts to use UNSCR 1325 to achieve gender empowerment. Ultimately, however, UNSCR 1325 is not radical enough to be used as a transformative gender mainstreaming tool.
Compact dual-mode rectangular waveguide filters using square ridge resonators
Authors: Bastioli Simone , Marcaccioli Luca , Sorrentino Roberto
Published: June 2009

A new class of compact rectangular waveguide filters is proposed in this paper. The key element is a square ridge resonator realized within a rectangular waveguide supporting the fundamental TE10 mode. The square ridge can support two modes resonating along orthogonal directions in the gap between the ridge and the opposite waveguide wall. This structure enables dual-mode degeneracy without the need of oversized cavities, thus allowing for considerable size reduction with respect to the conventional dual-mode implementations. Different filter structures employing one or more ridges within short waveguide sections are proposed as attractive solutions for pseudo-elliptic band-pass or dual-band filters. The experimental results of a manufactured fourth-order pseudo-elliptic pass-band filter validate the feasibility of the proposed class of filters.
Carbon cycling under 300 years of land use change: Importance of the secondary vegetation sink
Authors: Shevliakova Elena , Pacala Stephen W. , Malyshev Sergey , Hurtt George C. , Milly P. C. D. , Caspersen John P. , Sentman Lori T. , Fisk Justin P. , Wirth Christian , Crevoisier Cyril
Published: June 2009

We have developed a dynamic land model (LM3V) able to simulate ecosystem dynamics and exchanges of water, energy, and CO2 between land and atmosphere. LM3V is specifically designed to address the consequences of land use and land management changes including cropland and pasture dynamics, shifting cultivation, logging, fire, and resulting patterns of secondary regrowth. Here we analyze the behavior of LM3V, forced with the output from the Geophysical Fluid Dynamics Laboratory (GFDL) atmospheric model AM2, observed precipitation data, and four historic scenarios of land use change for 1700–2000. Our analysis suggests a net terrestrial carbon source due to land use activities from 1.1 to 1.3 GtC/a during the 1990s, where the range is due to the difference in the historic cropland distribution. This magnitude is substantially smaller than previous estimates from other models, largely due to our estimates of a secondary vegetation sink of 0.35 to 0.6 GtC/a in the 1990s and decelerating agricultural land clearing since the 1960s. For the 1990s, our estimates for the pastures' carbon flux vary from a source of 0.37 to a sink of 0.15 GtC/a, and for the croplands our model shows a carbon source of 0.6 to 0.9 GtC/a. Our process‐based model suggests a smaller net deforestation source than earlier bookkeeping models because it accounts for decelerated net conversion of primary forest to agriculture and for stronger secondary vegetation regrowth in tropical regions. The overall uncertainty is likely to be higher than the range reported here because of uncertainty in the biomass recovery under changing ambient conditions, including atmospheric CO2 concentration, nutrients availability, and climate.
Methane and nitrous oxide emissions from the ocean: A reassessment using basin‐wide observations in the Atlantic
Authors: Rhee T. S. , Kettle A. J. , Andreae M. O.
Published: June 2009

We measured the concentrations of nitrous oxide (N2O) and methane (CH4) in the marine boundary layer and surface waters of the Atlantic Ocean from ∼50°N to ∼50°S during the Atlantic Meridional Transect expedition (AMT‐7) in 1998. The cruise track transects a variety of meteorological and oceanographic regimes. Unusually high mixing ratios of atmospheric CH4 were observed in the extratropical Northern Hemisphere, coinciding with globally high levels of CH4 associated with the El Niño event of 1998. Atmospheric N2O remained nearly invariable during the expedition, with only a small hemispheric difference (0.82 ppb). Throughout the cruise, these gases were saturated or supersaturated in the water. The coastal region was observed to be a significant source of CH4, while upwelling regions acted as strong N2O emission sources. We estimated the global oceanic emission of CH4 to be 0.6–1.2 Tg a−1, comparable to previous estimates from basin‐wide observations. However, our estimate turns out to be ∼10 times lower than the value in the 1990 to 2007 Intergovernmental Panel on Climate Change (IPCC) reports, which essentially all relied on the estimate by Ehhalt (1974). A bias toward high CH4 saturation anomalies is probably responsible for the overestimation of the marine CH4 source in the IPCC reports. The CH4 saturation anomaly in the ocean appears to have remained constant over an interval of 20 years in spite of the increase of atmospheric CH4, suggesting that the increase of the surface water temperature driven by global warming may be a major factor. Meanwhile, the N2O emission from the ocean, estimated in the present study to be 0.9–1.7 Tg N a−1, is ∼3 times lower than the value in the recent IPCC report [Denman et al., 2007], implying either weak upwelling activity or low amounts of dissolved N2O in upwelling subsurface waters, or both, in the Atlantic.
A study of precipitation scavenging of semivolatile organic compounds in a tropical area
Authors: He Jun , Balasubramanian Rajasekhar
Published: June 2009

Rain samples were collected concurrently with gas phase and particulate samples from June 2007 to May 2008 in Singapore and processed to investigate precipitation scavenging of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs). A comprehensive atmospheric scavenging model has been developed with inclusion of major atmospheric deposition processes such as particle scavenging, dissolution (Henry's law), and surface adsorption affecting the total scavenging ratio of SVOCs. This model was subsequently used in this study to calculate precipitation ratios. Total scavenging ratios ranged from (8.9 ± 4.3) × 104 to (1.2 ± 0.4) × 106 for PAHs and from (8.3 ± 5.1) × 104 to (4.9 ± 1.5) × 105 for OCPs. Particle scavenging rather than gas scavenging was the dominant removal mechanism, accounting for 86–99% for PAHs and 98–99% for OCPs in terms of the particle contribution to the total scavenging. The variation of both total and particle scavenging ratios over the study period is smaller compared to those reported in the literature, which might be attributed to uniform ambient temperature prevailing throughout the year in this tropical area. The effects of particle fraction, supercooled vapor pressure, and rainfall intensity on particle scavenging of SVOCs were assessed. The relationship between gas scavenging ratio and supercooled vapor pressure implied that the domination of gas scavenging might switch from dissolution to adsorption at supercooled vapor pressures around 10−3.5–10−4 Pa, especially for PAHs with five or more aromatic rings. The equations used to estimate total scavenging (WT) based on the particle fraction (Φ) can be summarized as log WT = 0.94 log Φ + 6.09 (R2 = 0.74) for PAHs and log WT = 0.82 log Φ + 6.34 (R2 = 0.62) for OCPs.
Origin of rhythmic Albian black shales (Piobbico core, central Italy): Calcareous nannofossil quantitative and statistical analyses and paleoceanographic reconstructions
Authors: Tiraboschi Daniele , Erba Elisabetta , Jenkyns Hugh C.
Published: June 2009

The mid‐Cretaceous (∼120–90 Ma) was a time of excess atmospheric CO2, greenhouse climate, and widespread O2 deficiency in the ocean. The Albian is punctuated by brief, intermittent episodes of anoxia/dysoxia, recorded as cyclic black shales in the western Tethys and Atlantic oceans. The Albian section of the Piobbico core (central Italy) contains 30 m (∼10 Ma) of rhythmic black shales that were sampled at a high resolution and examined for calcareous nannofossil assemblages and C and O stable isotopes. Unlike oceanic anoxic events, productivity was not the primary factor controlling the deposition of Albian rhythmic black shales. It is suggested that during warm humid climatic cycles, higher temperatures and/or increased precipitation and runoff produced density stratification at a regional scale. Recurrent lowered salinity in the early Albian and warming in the late Albian are credited with causing development of a pycnocline, resulting in slower rates of deep‐water renewal and consequent anoxia.
Impact of a permanent El Niño (El Padre) and Indian Ocean Dipole in warm Pliocene climates
Authors: Shukla Sonali P. , Chandler Mark A. , Jonas Jeff , Sohl Linda E. , Mankoff Ken , Dowsett Harry
Published: June 2009

Pliocene sea surface temperature data, as well as terrestrial precipitation and temperature proxies, indicate warmer than modern conditions in the eastern equatorial Pacific and imply permanent El Niño–like conditions with impacts similar to those of the 1997/1998 El Niño event. Here we use a general circulation model to examine the global‐scale effects that result from imposing warm tropical sea surface temperature (SST) anomalies in both modern and Pliocene simulations. Observed SSTs from the 1997/1998 El Niño event were used for the anomalies and incorporate Pacific warming as well as a prominent Indian Ocean Dipole event. Both the permanent El Niño (also called El Padre) and Indian Ocean Dipole (IOD) conditions are necessary to reproduce temperature and precipitation patterns consistent with the global distribution of Pliocene proxy data. These patterns may result from the poleward propagation of planetary waves from the strong convection centers associated with the El Niño and IOD.
Are historical records sufficient to constrain ENSO simulations?
Authors: Wittenberg Andrew T.
Published: June 2009

A control simulation of the GFDL CM2.1 global coupled GCM, run for 2000 years with its atmospheric composition, solar irradiance, and land cover held fixed at 1860 values, exhibits strong interdecadal and intercentennial modulation of its ENSO behavior. To the extent that such modulation is realistic, it could attach large uncertainties to ENSO metrics diagnosed from centennial and shorter records – with important implications for historical and paleo records, climate projections, and model assessment and intercomparison. Analysis of the wait times between ENSO warm events suggests that such slow modulation need not require multidecadal memory; it can arise simply from Poisson statistics applied to ENSO's interannual time scale and seasonal phase‐locking.
Response of the equatorial and low‐latitude ionosphere in the Indian sector to the geomagnetic storms of January 2005
Authors: Sreeja V. , Devasia C. V. , Ravindran Sudha , Pant Tarun Kumar , Sridharan R.
Published: June 2009

The equatorial and low‐latitude ionospheric response to three moderate geomagnetic storms (17, 18, and 22 January) during the period from 16 to 23 January 2005 is investigated in the context of development/inhibition of the Equatorial Ionization Anomaly (EIA) and the subsequent occurrence/nonoccurrence of Equatorial Spread F (ESF) irregularities on these days. The study is carried out using the Total Electron Content (TEC) measured with the GPS receivers along the ∼80°E longitude sector and the F‐layer bottom height obtained from the Ionosonde located over the dip equatorial location of Trivandrum (8.5°N, 77°E, dip latitude ∼0.5°N) in India. It is observed that, for the storms on days 17 and 22, the development of the anomaly was inhibited, probably due to the westward disturbance dynamo electric fields. Subsequently, the post sunset enhancement in the vertical drift of the equatorial F region was also inhibited significantly compared to the quiet day pattern and, as anticipated, no ESF was observed on these days. A large vertical drift of the equatorial F region followed by nearly simultaneous onset of weak ESF was observed on day 18. The late development of the EIA on this day could be due to the eastward prompt penetration electric field associated with the southward turning of the interplanetary magnetic field. Also, strong and distinct F3 layer appeared for a short time in the morning, reappeared later in the noon time, and then quickly ascended to the topside ionosphere during the main phase of the storm on day 18.
A new multivariate time series data analysis technique: Automated detection of flux transfer events using Cluster data
Authors: Karimabadi H. , Sipes T. B. , Wang Y. , Lavraud B. , Roberts A.
Published: June 2009

A new data mining technique called MineTool‐TS is introduced which captures the time‐lapse information in multivariate time series data through extraction of global features and metafeatures. This technique is developed into a JAVA‐based data mining software which automates all the steps in the model building to make it more accessible to nonexperts. As its first application in space sciences, MineTool‐TS is used to develop a model for automated detection of flux transfer events (FTEs) at Earth's magnetopause in the Cluster spacecraft time series data. The model classifies a given time series into one of three categories of non‐FTE, magnetosheath FTE, or magnetospheric FTE. One important feature of MineTool‐TS is the ability to explore the importance of each variable or combination of variables as indicators of FTEs. FTEs have traditionally been identified on the basis of their magnetic field signatures, but here we find that some plasma variables can also be effective indicators of FTEs. For example, the perpendicular ion temperature yields a model accuracy of ∼93%, while a model based solely on the normal magnetic field BNyields an accuracy of ∼95%. This opens up the possibility of searching for more unusual FTEs that may, for example, have no clear BNsignature and create a more comprehensive and less biased list of FTEs for statistical studies. We also find that models using GSM coordinates yield comparable accuracy to those using boundary normal coordinates. This is useful since there are regions where magnetopause models are not accurate. Another surprising result is the finding that the algorithm can largely detect FTEs, and even distinguish between magnetosheath and magnetospheric FTEs, solely on the basis of models built from single parameters, something that experts may not do so straightforwardly on the basis of short time series intervals. The most accurate models use a combination of plasma and magnetic field variables and achieve a very high accuracy of prediction of ∼99%. We explain the high detection accuracies both in terms of the existence of clear physical signatures of FTEs (for the majority of cases) and in terms of the capability of the data mining technique to explore the data set in a much more thorough fashion than expert human eyes. A list of 1222 FTEs from Cluster data during years 2001–2003 is provided as auxiliary material.
Searching for ULF signatures of the cusp: Observations from search coil magnetometers and auroral imagers in Svalbard
Authors: Engebretson Mark J. , Moen Joran , Posch Jennifer L. , Lu Fei , Lessard Marc R. , Kim Hyomin , Lorentzen Dag A.
Published: June 2009

Spacecraft traveling through the cusp at a variety of altitudes have consistently found the cusp to be filled with intense, often irregular power in the upper ULF frequency range. Some ground‐based studies have observed narrowband waves in this same frequency range in the vicinity of the cusp foot point, but it has not been possible with magnetometers alone to either confirm or deny a cusp source for these waves. We report here on the first simultaneous, collocated observations of a set of induction magnetometers installed at three near‐cusp sites on Svalbard and an all‐sky auroral imager located at Longyearbyen. Data during northern winters of 2006–2007 and 2007–2008, when the cusp foot point was in darkness, showed occasional broadband noise when energetic particle precipitation occurred overhead, but on most days no broadband ULF power was observed above the noise level near noon when only soft cusp precipitation or poleward moving auroral forms occurred overhead. However, on 3 days, including 15 January 2007, several bursts of band‐limited Pc 1‐2 waves were observed in association with regions of intense soft precipitation that peaked near the poleward edge of the cusp. Their properties are consistent with an origin in the plasma mantle, as observed in a recent satellite‐ground study by Engebretson et al. (2005). These observations confirm that even intense cusp precipitation is not effective in generating ion cyclotron waves that penetrate to the ground, if it is embedded within the central regions of the cusp, whereas regions of enhanced precipitation at the poleward edge of the cusp are associated with observed waves.
Electron scattering due to dislocation wall strain field in GaN layers
Authors: Krasavin S.
Published: June 2009

The effect of edge-type dislocation wall strain field on the Hall mobility in n-type epitaxial GaN was theoretically investigated through the deformation potential within the relaxation time approximation. It was found that this channel of scattering can play a considerable role in the low temperature transport at the certain set of the model parameters. The low temperature experimental data were fitted by including this mechanism of scattering along with ionized impurity and charge dislocation ones.
Multifrequency cloak with multishell by using transformation medium
Authors: Gao Y. , Huang J. P. , Yu K. W.
Published: June 2009

We theoretically investigate multifrequency cloak based on multishell by using transformation medium. As for each shell, we use the Maxwell–Garnett theory and the spectral representation theory to design the permittivity profile for the transverse magnetic wave. The plasma frequencies of the metals used in the inner (B) and outer (C) shells must satisfy ω1<ωpC<ω2<ωpB. In such case, incident electromagnetic wave of lower frequency ω1 will be distorted only by the outer shell C without entering the inner shell B to achieve invisibility. However, at the higher operating frequency ω2, the outer shell C is transparent by choosing the materials appropriately, and the incident electromagnetic wave will be distorted only by the inner shell B to achieve invisibility. So, the multishell cloak can work simultaneously on two different optical frequencies. Furthermore, we use the anisotropic differential effective dipole theory to evaluate the efficiency of the cylindrical cloak.
Electrical stress-induced charge carrier generation/trapping related degradation of HfAlO/SiO2 and HfO2/SiO2 gate dielectric stacks
Authors: Samanta Piyas , Cheng Chin-Lung , Lee Yao-Jen , Chan Mansun
Published: June 2009

A comparative study on charge carrier generation/trapping and related degradation in HfAlO/SiO2 and HfO2/SiO2 stacks with identical equivalent-oxide-thickness (EOT) is presented during constant gate voltage stress of n-type metal-oxide-semiconductor capacitors. Compared to HfO2 devices, HfAlO devices with an equal EOT show better performances in memory and logic applications. On the contrary, at a given stress voltage, the threshold voltage degradation and stress-induced leakage current degradation in HfAlO samples are higher, indicating shorter device lifetime compared to the HfO2 samples of same EOT. In addition, the mechanism of charge trapping in the oxide as well as at the Si/SiO2 interface of both capacitors is investigated and a model is proposed. A similar generation kinetics was observed for stress-induced oxide trapped positive charges and interface states in either of the devices.
Microstructural aspects for defect emission and E2high phonon mode of ZnO thin films
Authors: Ghosh Avijit , Choudhary R. N. P.
Published: June 2009

The ZnO thin films were prepared using a cost-effective vacuum-carbon-arc technique combined with thermal oxidation under ambient conditions from zinc nanoparticles in carbon matrix. The microstructural analysis of grazing incidence x-ray diffraction pattern using Rietveld method was investigated systematically under the influence of different annealing temperature. Photoluminescence spectroscopic properties of the samples studied at room temperature exhibits the dependence of violet emission accompanying with blue and green emission on oxidation temperature. The origin of defect emission mechanism through the microstructure of ZnO thin films was analyzed. The anharmonic properties of the upper E2 phonon mode were investigated using Raman scattering spectroscopy at room temperature. The downshift of phonon frequency and linewidth broadening of high frequency E2 phonon mode were analyzed through defect state according to annealed conditions.
Small-scale effect on vibration analysis of single-walled carbon nanotubes embedded in an elastic medium using nonlocal elasticity theory
Authors: Pradhan S. C. , Murmu T.
Published: June 2009

Nonlocal elasticity theory is a growing technique for the mechanical analyses of microelectromechanical (MEMS) and nanoelectromechanical (NEMS) based structures. The nonlocal parameter accounts for the small size effects when dealing with nanosize structures such as single-walled carbon nanotubes (SWCNTs). In this article, nonlocal elasticity and Timoshenko beam theory are implemented to study the vibration response of SWCNT embedded in an elastic medium. Influence of the surrounding elastic medium on the fundamental frequencies of the SWCNT is investigated. Both Winkler-type and Pasternak-type foundation models are employed to simulate the interaction of the SWCNT with the surrounding elastic medium. A differential quadrature approach is being utilized and numerical solutions for the natural frequencies are obtained. Influences of nonlocal effects, Winkler modulus parameter, Pasternak shear modulus parameter, and aspect ratio on the frequency of SWCNT are analyzed and discussed. The present study illustrates that the frequencies of embedded SWCNT are significantly dependent on the nonlocal parameter and on the stiffness of the surrounding elastic medium.
A molecular dynamics study of chirality transfer from chiral surfaces to nearby solvent
Authors: Wang Shihao , Cann N. M.
Published: June 2009

The presence of a chiral surface can alter the characteristics of nearby solvent molecules such that, on average, these molecules become chiral. The extent of this induced chirality and its dependence on the surface and solvent characteristics are explored in this article. Three surfaces employed in chiral chromatography are examined: The Whelk-O1 interface, a phenylglycine-derived chiral stationary phase (CSP), and a leucine-derived CSP. All three interfaces are “brush type” in that the chiral molecules are attached to the underlying substrate via an achiral tether. The solvents consist of ethanol, a binary n-hexane/ethanol solvent, 2-propanol, and a binary n-hexane/2-propanol solvent. Molecular dynamics simulations of the solvated chiral interfaces form the basis of the analysis. The chirality induced in the solvent is assessed based on a chirality index originally proposed by Osipov et al. [Mol. Phys. 84, 1193 (1995)]. Solvent chirality will depend on the solvent position relative to the surface. For this reason, a position-dependent chirality index is analyzed in detail.