bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial distribution of the invasive bivalve Isognomon bicolor on rocky shores of Arvoredo Island (Santa Catarina, Brazil)
Authors: Martinez A.S.
Published: July 2011

The invasion of marine species is a threat to local and global biodiversity and can have many ecological, economic and social impacts. The bivalve Isognomon bicolor has invaded the rocky shores of Brazil and spread along the coast, occurring from Rio Grande do Norte to the Santa Catarina State. The present study evaluated the distribution of I. bicolor on different rocky shores of Arvoredo Island (Santa Catarina State) and its relationship with other taxa. A high density of I. bicolor was found on the exposed shore, which was associated with the occurrence of articulated calcareous macroalgae. In addition, I. bicolor was also found in empty shells of the barnacles Tetraclita stalactifera and Megabalanus spp. The physical structure of these habitats probably plays an important role in the success of I. bicolor invasion. For these reasons, I. bicolor evidences an alteration on the benthic community of the rocky shores and its potential consequences become a threat to local species.
Pathologies in commercial bivalve species from Santa Catarina State, southern Brazil
Authors: da Silva Patricia Mirella , Magalhães Aimê Rachel Magenta , Barracco Margherita Anna
Published: July 2011

The State of Santa Catarina in southern Brazil is the most important Brazilian producer region. The Pacific oysters Crassostrea gigas and the brown mussels Perna perna are the main species currently produced. The occurrence and impact of parasites on bivalves from natural or culture populations from Brazil are still poorly studied. This work describes several diseases, parasites and commensals from four edible bivalve species, from cultured and exploited stocks, from five sites at Santa Catarina State. Unspecific histopathological symptoms of stress, parasites and commensals were found, including viral gametocytic hypertrophy and rickettsia-like organisms with very low prevalences; the protozoan Nematopsis sp. with high prevalence and, ovarian parasites with low prevalences; and, diverse metazoans, such as turbellarian, sporocysts and metacercariae of trematodes, metacestoda larvae and spionid polychaete. Ray's fluid thioglycollate medium assays for detection of Perkinsus spp. did not detect any infected bivalves. Polymerase chain reaction assays for Marteiliodies chungmuensis in oysters with ovarian lesions produced negative results.
Tracing the fate of dietary fatty acids: metabolic studies of postprandial lipaemia in human subjects
Authors: Fielding Barbara
Published: July 2011

Most postprandial studies have investigated the response of a single meal, yet the ingestion of sequential meals is more typical in a Western society. The aim of this review is to explain how natural and stable isotope tracers of fatty acids have been used to investigate the metabolism of dietary fat after single and multiple meals, with a focus onin vivomeasurements of adipose tissue metabolism. When stable isotope tracers are combined with arteriovenous difference measurements, very specific measurements of metabolic flux across tissues can be made. We have found that adipose tissue is a net importer of dietary fat for 5 h following a single test meal and for most of the day during a typical three-meal eating pattern. When dietary fat is cleared from plasma, some fatty acids ‘spillover’ into the plasma and contribute up to 50% of postprandial plasma NEFA concentrations. Therefore, plasma NEFA concentrations after a meal reflect the balance between intracellular and extracellular lipolysis in adipose tissue. This balance is altered after the acute ingestion of fructose. The enzyme lipoprotein lipase is a key modulator of fatty acid flux in adipose tissue and its rate of action is severely diminished in obese men. In conclusion,in vivostudies of human metabolism can quantify the way that adipose tissue fatty acid trafficking modulates plasma lipid concentrations. This has implications for the flux of fatty acids to tissues that are susceptible to ectopic fat deposition such as the liver and muscle.
Martin Luther's Political Interpretation of the Song of Songs
Authors: Carty Jarrett A.
Published: July 2011

Martin Luther argued that the Hebrew Bible's Song of Songs was “an encomium of the political order,” a praise and thanksgiving to God for the gift of temporal government. Luther's political interpretation of this book was unique in his age, and remains so in the history of biblical commentary. This paper offers an account of Luther's peculiar interpretation, as well as its place in his interpretation of the Bible and in the history of biblical commentary, by arguing that it exhibits the foundational idea of his political thought that secular authority is a precious gift from God, and that the Song of Songs, as a praise of conjugal love, provides for political authority a fitting biblical encomium.
A minimum income for healthy living (MIHL) – older New Zealanders
Authors: O'SULLIVAN JESSICA , ASHTON TONI
Published: July 2011

Governments around the developed world are seeking to meet the challenges of the ageing population through strategies which promote a holistic approach to ageing, captured in catch-phrases such as ‘successful’, ‘active’, ‘positive’ and ‘healthy’ ageing. These strategies are supported by a growing body of research, with a particular emphasis on the prerequisites for health and quality of life. Drawing on that research, and using a methodology developed by the London School of Hygiene and Tropical Medicine, the ‘Minimum Income for Healthy Living (MIHL): Older New Zealanders’ study used a health lens to investigate the retirement income needs of older New Zealanders living independently in the community. The MIHL was estimated for people living alone, couples, renters and debt-free home owners. In each case, the MIHL estimates were appreciably higher than the universal state pension paid to older New Zealanders. People living alone and those renting their homes were shown to be worse off than couples and debt-free home owners, respectively. The results highlight that many older New Zealanders are living on an income which may not be enough to support a healthy life. This has important implications for the demand for health, residential and social services and brings life to the question of what level of income might be needed in retirement.
There's no apprenticeship for Alzheimer's: the caring relationship when an older person experiencing dementia falls
Authors: MCINTYRE ANNE , REYNOLDS FRANCES
Published: July 2011

Older people experiencing dementia are twice as likely to fall with consequences of serious injury, reduction in everyday activity, admission to long-term care and mortality. Carers of people with dementia are themselves at greater risk of physical and mental ill health, which increases as the dementia progresses. Unsurprisingly, carer burden also increases when a care-recipient falls. The aim of this study was to explore the experiences of falling of community-living older people with dementia and their carers. A qualitative approach was taken using interpretative phenomenological analysis. Nine older people with predominantly Alzheimer's disease and their ten carers were recruited from a large mental health National Health Service trust and participated in one-to-one and joint in-depth interviews. Three dyads participated in repeat interviews. Three focus groups were also carried out, with nine older people experiencing memory problems and 12 carers from a local Alzheimer's Society branch. The antecedents, falls events and consequences of falls were discussed. This paper reports specifically on the impact of falls on the caring relationship. Three themes emerged: ‘learning as you go’, ‘we're always together’, ‘nobody was interested’. The findings demonstrate how falling accentuates the impact of dementia on the dyad. Spouse-carers' discussion of their own falls emphasise the need for joint assessment of health and wellbeing to reduce carer burden and preserve the couplehood of the dyad.
Safe passage of goods and self during residential relocation in later life
Authors: EKERDT DAVID J. , LUBORSKY MARK , LYSACK CATHERINE
Published: July 2011

Techniques of possession research among older people tend to accentuate their prizing of things and their use of special dispositions to achieve the protection or ‘safe passage’ of things as they transfer to a new owner. Such efforts on behalf of possessions may also be undertaken to perpetuate the self. To study the care of things and self in a wider context, we examined older people's repertoire of disposition strategies during episodes of household relocation and downsizing. We analysed the narratives of persons in 75 households in the Midwestern United States of America. People indeed told stories about the safe passage of cherished possessions – their initiative to place things, appreciation by new owners, and attempts to project the values or memory of the giver. Such accounts of special placements, however, dotted rather than dominated recollections of the move. More commonly, large quantities of items were passed via non-specific offers of possessions to others who may volunteer to take them. This allowed people to nonetheless express satisfaction that their possessions had found appreciative owners. Even though our interviews did not disclose extensive attempts at self-transmission, whole-house downsizing may affirm the self in another way: as conscientious about the care of things. Such affirmation of the present self as accomplished and responsible can be seen as a positive adaptation to the narrowing life world.
The impact of the Bealtaine arts programme on the quality of life, wellbeing and social interaction of older people in Ireland
Authors: O'SHEA EAMON , LÉIME ÁINE NÍ
Published: July 2011

There is increasing evidence in the international literature that engagement in the arts can enhance the physical and psychological wellbeing of older people. Such engagement can increase the self-confidence and morale of older people and provide opportunities for increased social connections, leading to higher levels of social cohesion. This article is based on an evaluation of a national arts festival in Ireland called Bealtaine that celebrates creativity in older people each year during the month of May. The festival is unique in the wide range of arts-related activities it includes and the different types of organisations involved, such as local authorities, libraries, educational institutions, health and social care organisations, and voluntary bodies for older people. It includes both long-standing professionally facilitated arts programmes and one-off events at local and national levels. The evaluation used quantitative and qualitative methods to analyse two major postal surveys with organisers and consumers of the festival and face-to-face interviews with older participants, artists and organisers. The findings are overwhelmingly positive in terms of the personal and social gains arising from participation in the festival. In this context, the study provides support for the provision of enhanced and sustained funding for creative programmes for older people and, more generally, for the development of an integrated policy for older people and the arts in the country.
Subjective well-being amongst community-dwelling elders: what determines satisfaction with life? Findings from the Dublin Healthy Aging Study
Authors: Ní Mhaoláin Aine M. , Gallagher Damien , O Connell Henry , Chin A. V. , Bruce Irene , Hamilton Fiona , Teehee Erin , Coen Robert , Coakley Davis , Cunningham Conal , Walsh J. B. , Lawlor Brian A.
Published: July 2011

Background: Life satisfaction is a subjective expression of well-being and successful aging. Subjective well-being is a major determinant of health outcomes in older people. The aim of this study was to determine which factors predicted well-being in older people living in the community as measured by their satisfaction with life.

Methods: The relationship between life satisfaction, as measured by the Life Satisfaction Index (LSI-A) and physical, cognitive and demographic variables was examined in 466 older people living in the community using a stepwise regression model

Results: Depression, loneliness, neuroticism, extraversion, recent participation in physical activity, age and self-reported exhaustion, were the independent predictors of life satisfaction in our elderly cohort.

Conclusion: Subjective well-being, as measured by the Life Satisfaction Scale, is predicted by depression, loneliness, personality traits, recent participation in physical activity and self-reported exhaustion. The mental and emotional status of older individuals, as well as their engagement in physical activity, are as important as physical functionality when it comes to life satisfaction as a measure of well-being and successful aging. These areas represent key targets for intervention.
Smith–Lemli–Opitz syndrome
Authors: DeBarber Andrea E. , Eroglu Yasemen , Merkens Louise S. , Pappu Anuradha S. , Steiner Robert D.
Published: July 2011

Smith–Lemli–Opitz syndrome (SLOS) is an autosomal recessive, multiple congenital malformation and intellectual disability syndrome, with clinical characteristics that encompass a wide spectrum and great variability. Elucidation of the biochemical and genetic basis for SLOS, specifically understanding SLOS as a cholesterol deficiency syndrome caused by mutation inDHCR7, opened up enormous possibilities for therapeutic intervention. When cholesterol was discovered to be the activator of sonic hedgehog, cholesterol deficiency with inactivation of this developmental patterning gene was thought to be the cause of SLOS malformations, yet this explanation is overly simplistic. Despite these important research breakthroughs, there is no proven treatment for SLOS. Better animal models are needed to allow potential treatment testing and the study of disease pathophysiology, which is incompletely understood. Creation of human cellular models, especially models of brain cells, would be useful, and in vivo human studies are also essential. Biomarker development will be crucial in facilitating clinical trials in this rare condition, because the clinical phenotype can change over many years. Additional research in these and other areas is critical if we are to make headway towards ameliorating the effects of this devastating condition.
Unemployment, human capital depreciation and pension benefits: an empirical evaluation of German data
Authors: POTRAFKE NIKLAS
Published: July 2011

This paper investigates empirically how unemployment-induced employment-breaks at different career stages influence pension benefits. The analysis is based on German data. I distinguish four different career phases and investigate to what extent the prevailing social security policy compensated for earning losses. The results suggest that (1) losses in pension benefits were the greatest if unemployment occurred in the middle of a career (between 31 and 50); (2) social security policies have had a mitigating effect on losses in pension benefits. These findings indicate that institutions have a decided influence on how career patterns translate into pension benefits.
Genetic diversity and structure of the threatened anti-cancerous plantNothapodytes nimmonianaas revealed by ISSR analysis
Authors: Abdul Kareem V. K. , Rajasekharan P. E. , Mini S. , Vasantha Kumar T.
Published: July 2011

Inter simple sequence repeat markers were used to assess the genetic diversity and population genetic structure in 12 populations ofNothapodytes nimmonianafrom Western Ghats of India. A total of 16 selected primers produced 103 discernible bands, with 76 (73.7%) being polymorphic. The Nei's gene diversity (h) ranged from 0.1166 to 0.2124, with an average of 0.1518 at the population level and 0.2965 at the species level indicating high genetic diversity. The Shannon's index (I) was estimated to be 0.2189 within populations (range 0.1703–0.2947) and 0.4352 at the species level. The analysis of molecular variance showed that the genetic variation was found mainly within populations (73%), but variance among populations was only 27% and its value, ΦPT = 0.271,P < 0.001, implied that high genetic differentiation among populations. In addition, Nei's differentiation coefficient (GST) was found to be high (0.4882) and the gene flow (Nm) was low (0.5242), confirming the high population genetic differentiation. The unweighted pair-group method using arithmetic average clustering elicited similar results. Based on this, we propose conservation strategy for this plant species.
AlleleCoder: a PERL script for coding co-dominant polymorphism data for PCA
Authors: Baldo Angela M. , Francis David M. , Caramante Martina , Robertson Larry D. , Labate Joanne A.
Published: July 2011

A useful biological interpretation of diploid heterozygotes is in terms of the dose of the common allele (0, 1 or 2 copies). We have developed a PERL script that converts FASTA files into coded spreadsheets suitable for principal component analysis. In combination with R and R Commander, two- and three-dimensional plots can be generated for visualizing genetic relationships. Such plots are useful for characterizing plant genetic resources. This method nicely illustrated the spectrum of genetic diversity in tomato landraces and the varieties categorized according to human-mediated dispersal.
Pore‐scale determination of parameters for macroscale modeling of evaporation processes in porous media
Authors: Ahrenholz B. , Niessner J. , Helmig R. , Krafczyk M.
Published: July 2011

Evaporation is an important process in many natural and technical systems, such as the unsaturated zone of the subsurface or microchannel evaporators. For the understanding and prediction of the involved processes, numerical simulations of multiphase flow and transport processes are an important tool. In order to achieve an accurate, physically based description of kinetic interphase mass and heat transfer occurring during evaporation, the numerical model has to account for the interfacial areas between phases. A recently developed model for two‐phase flow in porous media is able to account for the involved processes by using interfacial areas explicitly as parameters in the model. The crucial issue, however, is the determination of the relationships between specific interfacial areas, capillary pressure, and saturation in this paper, we present a multiphase lattice Boltzmann model, which allows us to determine these relationships. On the basis of the scanned geometry of a natural porous medium, the relationships between specific interfacial areas, capillary pressure, and saturation are determined. To the best of our knowledge, this is the first time that fluid‐solid specific interfacial area relationships have been obtained from pore‐scale data. Using these functions, we present the results of macroscale simulations of an evaporator device and of drying in a porous medium.
RodZ regulates the post‐transcriptional processing of the Shigella sonnei type III secretion system
Authors: Mitobe Jiro , Yanagihara Itaru , Ohnishi Kiyouhisa , Yamamoto Shouji , Ohnishi Makoto , Ishihama Akira , Watanabe Haruo
Published: July 2011

The expression of the type III secretion system—a main determinant of virulence in Shigella—is controlled by regulator cascades VirF‐InvE (VirB) and CpxAR two‐component system. A screen for mutants that restore virulence in the cpxA background led to the isolation of a mutant of rodZ, a cytoskeletal protein that maintains the rod‐shaped morphology of bacilli. InvE is normally repressed at 30 °C because of decreased messenger RNA (mRNA) stability, but rodZ mutants markedly increase invE‐mRNA stability. Importantly, the inhibition of InvE production by RodZ can be genetically separated from its role in cell‐shape maintenance, indicating that these functions are distinguishable. Thus, we propose that RodZ is a new membrane‐bound RNA‐binding protein that provides a scaffold for post‐transcriptional regulation.
Analysis of Nebivolol hydrochloride and Valsartan in Pharmaceutical Dosage Form by High Performance Thin Layer Chromatographic Method
Authors: Singh Shradhanjali , Singh Anil , Mishra Shanti , Mukerjee Alok , Damle Mrinalini
Published: July 2011

A simple, accurate and precise high performance thin layer chromatographic method has been developed for the estimation of Valsartan and Nebivolol hydrochloride simultaneously from a tablet dosage form. The method employed silica gel 60 F254 pre-coated plates as stationary phase and a mixture of Ethyl acetate: Methanol: Ammonia (6.5:2.5:0.5 %v/v/v) as mobile phase. Densitometric scanning was performed at 280 nm using a Camag TLC scanner 3. Beer’s law was obeyed in the concentration range of 800ng/spot-2400ng/spot for Nebivolol hydrochloride and 200ng/spot-1000ng/spot for Valsartan. The Retention factor for Nebivolol hydrochloride is 0.75 ± 0.04 and is 0.27 ± 0.01 for Valsartan . The method was validated as per ICH Guidelines, proving its utility in estimation of Valsartan and Nebivolol hydrochloride in combined dosage form.
Monoclonal antibodies reveal the alteration of the rhodocetin structure upon α2β1 integrin binding
Authors: Bracht Thilo , Figueiredo de Rezende Flávia , Stetefeld Jörg , Sorokin Lydia M. , Eble Johannes A.
Published: July 2011

The α2β1 antagonist rhodocetin from Calloselasma rhodostoma is a heterotetrameric CLRP (C-type lectin-related protein) consisting of four distinct chains, α, β, γ and δ. Via their characteristic domain-swapping loops, the individual chains form two subunits, αβ and γδ. To distinguish the four chains which share similar molecular masses and high sequence homologies, we generated 11 mAbs (monoclonal antibodies) with different epitope specificities. Four groups of distinct mAbs were generated: the first targeted the rhodocetin β chain, the second group bound to the αβ subunit mostly in a conformation-dependent manner, the third group recognized the γδ subunit only when separated from the αβ subunit, whereas a fourth group interacted with the γδ subunit both in the heterotetrameric molecule and complexed with the integrin α2 A-domain. Using the specific mAbs, we have shown that the rhodocetin heterotetramer dissociates into the αβ and γδ subunit upon binding to the integrin α2 A-domain at both the molecular and cellular levels. After dissociation, the γδ subunit firmly interacts with the α2β1 integrin, thereby blocking it, whereas the rhodocetin αβ subunit is released from the complex. The small molecular interface between the αβ and γδ subunits within rhodocetin is mostly mediated by charged residues, which causes the two dissociated subunits to have hydrophilic surfaces.
Rim2, a pyrimidine nucleotide exchanger, is needed for iron utilization in mitochondria
Authors: Yoon Heeyong , Zhang Yan , Pain Jayashree , Lyver Elise R. , Lesuisse Emmanuel , Pain Debkumar , Dancis Andrew
Published: July 2011

Mitochondria transport and utilize iron for the synthesis of haem and Fe–S clusters. Although many proteins are known to be involved in these processes, additional proteins are likely to participate. To test this hypothesis, in the present study we used a genetic screen looking for yeast mutants that are synthetically lethal with the mitochondrial iron carriers Mrs3 and Mrs4. Several genes were identified, including an isolate mutated for Yfh1, the yeast frataxin homologue. All such triple mutants were complemented by increased expression of Rim2, another mitochondrial carrier protein. Rim2 overexpression was able to enhance haem and Fe–S cluster synthesis in wild-type or Δmrs3/Δmrs4 backgrounds. Conversely Rim2 depletion impaired haem and Fe–S cluster synthesis in wild-type or Δmrs3/Δmrs4 backgrounds, indicating a unique requirement for this mitochondrial transporter for these processes. Rim2 was previously shown to mediate pyrimidine exchange in and out of vesicles. In the present study we found that isolated mitochondria lacking Rim2 exhibited concordant iron defects and pyrimidine transport defects, although the connection between these two functions is not explained. When organellar membranes were ruptured to bypass iron transport, haem synthesis from added iron and porphyrin was still markedly deficient in Rim2-depleted mitochondrial lysate. The results indicate that Rim2 is a pyrimidine exchanger with an additional unique function in promoting mitochondrial iron utilization.
Effects of electric field and shape on the bound polaron in a wurtzite ellipsoidal finite-potential quantum dot
Authors: Shi Lei , Yan Zuwei
Published: July 2011

The ground state of bound polaron in a weakly prolate ellipsoidal quantum dot in the presence of an external electric field has been calculated within the effective-mass approximation by using a variational method in the framework of perturbation theory. A Fröhlich-like electron-phonon interaction Hamiltonian which accounts for the longitudinal optical (LO) and transverse optical (TO) polarizations mixing due to the anisotropy is used in the calculation. The binding energy of the bound polaron is calculated by taking the electron couples with both branches of LO-like and TO-like phonons. The interaction between impurity and phonons has also been considered. The results show that the influence of phonons is dependent strongly upon the dot shape and the anisotropy effects of wurtzite crystals, and the influence of electric field is obvious only for the large quantum dot size. The TO-like phonon contribution to the binding energy is positive, but the contribution of LO-like phonon is negative and more important than TO-like phonon.
Quantum-confined direct-gap transitions in tensile-strained Ge/SiGe multiple quantum wells
Authors: Carroll Lee , Imbert Florian , Sigg Hans , Süess Martin , Müller Elisabeth , Virgilio Michele , Pizzi Giovanni , Rossbach Peggy , Chrastina Daniel , Isella Giovanni
Published: July 2011

Tensile-strained Ge/Si1−xGex (x = 0.87) multiple quantum wells (MQWs) on a Ge-on-Si virtual substrate are investigated with Brewster transmission and photo-reflectance, to identify quantum-confined direct-gap transitions and their light/heavy-hole splitting. Strain is deduced from optical splitting and x-ray diffraction measurements. As-prepared MQWs have an exciton at ≈ 820 meV, close to the 810 meV edge of the telecommunication C-band. The effect of rapid thermal annealing, to red-shift this feature into the C-band via increased strain, is investigated and interpreted with a tight-binding model. Annealing is observed to red-shift bulk absorption, but MQW transitions experience a net blue-shift due to interdiffusion.
Enhancement of glass-forming ability and corrosion resistance of Zr-based Zr-Ni-Al bulk metallic glasses with minor addition of Nb
Authors: Li Yanhui , Zhang Wei , Dong Chuang , Qin Chunling , Qiang Jianbing , Makino Akihiro , Inoue Akihisa
Published: July 2011

Cu-free Zr-based bulk metallic glasses (BMGs) with high glass-forming ability (GFA) have been discovered in the Zr-Ni-Al-Nb system. The GFA of Zr-Ni-Al alloys can be significantly enhanced by the minor addition of Nb, which increases the glass transition temperature, and lowers the melting and liquidus temperatures. The Zr-Ni-Al-Nb BMGs have critical sample diameters of 15–20 mm as verified by a copper mold casting. They exhibit excellent corrosion resistance in chloride-ion-containing solutions, which is considerably better than that of other known Zr-based BMGs with superhigh GFA. It was revealed that the formation of highly protective Zr-, Al-, and Nb-enriched surface film is responsible for the high corrosion resistance. The BMGs also possess high compressive yield strength of 1786–1847 MPa, large plastic strain of 1.6–3.2%, and a high Poisson’s ratio of 0.365–0.371.
Bistable transmission of antiferromagnetic Fabry-Perot resonator
Authors: Zhao Yan , Fu Shu-Fang , Li Hua , Wang Xuan-Zhang
Published: July 2011

We investigate the magnetically nonlinear optical transmission of the Fabry-Perot resonator filled with an antiferromagnetic medium. In a proper incident power range, we find very large nonlinear phase shifts so that the bistable switches appear even for a very thin medium film, such as of half-wavelength thickness. All results are based on antiferromagnetic MnF2 medium with far-infrared resonant frequencies.
A superconducting beta spectrometer
Authors: Knutson L. D. , Severin G. W. , Cotter S. L. , Zhan Li , Voytas P. A. , George E. A.
Published: July 2011

We have designed and constructed a superconducting beta spectrometer with a momentum resolution of about 2% and a peak solid angle of 0.5 sr. The performance of the spectrometer is described and the results of calibrations with line sources are presented.
Infrared spectroscopy of hydrated alkali metal cations: Evidence of multiple photon absorption
Authors: Beck Jordan P. , Lisy James M.
Published: July 2011

Infrared predissociation spectra of M+(H2O)4-7, where M = alkali metal, are presented. Hydrogen bonding O-H stretching features are strongly dependent on which fragmentation channel is monitored. Spectra recorded by monitoring the loss of multiple waters show a preference for one absorption feature in the hydrogen-bonded region centered at ∼3430–3500 cm−1, which is assigned to linear-type hydrogen bonded OH stretches. Cyclic- and bent-type hydrogen bonded OH stretches have diminished photodissociation cross sections in the multiple ligand loss channels. Evidence from Rice-Ramsperger-Kassel-Marcus–evaporative ensemble calculations and laser fluence dependence experiments indicates that the multiple water loss channels are primarily the result of multiple photon absorption which we propose could be due to multiple, independent oscillators within a cluster ion each absorbing a photon during a single, 10 ns laser pulse.
Self-focusing and defocusing of Gaussian laser beams in plasmas with linear temperature ramp
Authors: Zhou Zhongxiang , Wang Ying , Yuan Chengxun , Du Yanwei
Published: July 2011

The propagation characteristics of the Gaussian laser beam in plasmas in the presence of a linear electron temperature ramp have been investigated by taking the electron temperature as an individual variable. The ponderomotive force and collision have been considered as the mechanisms of nonlinearity. The second order differential equation of the dimensionless beam-width parameter has been acquired and solved with several initial electron temperatures and plus-minus temperature ramp parameters. The propagation regimes of laser beam are found to be sensitive with the selection of electron temperature. The linear temperature ramp breaks the stationary propagating mode and enhances the self-focusing or defocusing propagation properties. Results indicate the feasibility of extended propagation of focused laser beam in plasmas by modifying the electron temperature.
Fully kinetic simulation of ion acoustic and dust-ion acoustic waves
Authors: Hosseini Jenab S. M. , Kourakis I. , Abbasi H.
Published: July 2011

A series of numerical simulations is presented, based on a recurrence-free Vlasov kinetic model using kinetic phase point trajectories. All plasma components are modeled kinetically via a Vlasov evolution equation, then coupled through Poisson’s equation. The dynamics of ion acoustic waves in an electron-ion and in a dusty (electron-ion-dust) plasma configuration are investigated, focusing on wave decay due to Landau damping and, in particular, on the parametric dependence of the damping rate on the dust concentration and on the electron-to-ion temperature ratio. In the absence of dust, the occurrence of damping was observed, as expected, and its dependence to the relative magnitude of the electron vs ion temperature(s) was investigated. When present, the dust component influences the charge balance, enabling dust-ion acoustic waves to survive Landau damping even in the extreme regime where Te ≃ Ti. The Landau damping rate is shown to be minimized for a strong dust concentration or/and for a high value of the electron-to-ion temperature ratio. Our results confirm earlier theoretical considerations and contribute to the interpretation of experimental observations of dust-ion acoustic wave characteristics.
Ratchet effect induced by linearly polarized near- and mid-infrared radiation in InAs nanowires patterned quasi two-dimensional electron system
Authors: Jiang Chongyun , Ma Hui , Yu Jinling , Liu Yu , Chen Yonghai
Published: July 2011

In this letter, we studied the polarization dependent current excited by near- and mid-infrared radiations in InAs nanowires patterned quasi two-dimensional structures. We observed a current with a predominated direction along the wires at normal incidence of mid-infrared radiation and attributed it to the ratchet effect. Photogalvanic effect induced by obliquely incident excitation is also observed. Under near-infrared excitation, however, the normal incident ratchet effect becomes insignificant and the linear photogalvanic effect at oblique incidence dominantly contributes to the electric current.
Noise properties of a resonance-type spin-torque microwave detector
Authors: Prokopenko Oleksandr , Melkov Gennadiy , Bankowski Elena , Meitzler Thomas , Tiberkevich Vasil , Slavin Andrei
Published: July 2011

We analyze performance of a resonance-type spin-torque microwave detector (STMD) in the presence of noise and reveal two distinct regimes of STMD operation. In the high-frequency regime, the minimum detectable microwave power Pmin is limited by the low-frequency Johnson-Nyquist noise and the signal-to-noise ratio (SNR) of STMD is proportional to the input microwave power PRF. In the low-frequency regime, Pmin is limited by the magnetic noise, and the SNR is proportional to PRF. The developed formalism can be used for the optimization of the practical noise-handling parameters of a STMD.
Molecular-beam experiments for photodissociation of propenal at 157 nm and quantum-chemical calculations for migration and elimination of hydrogen atoms in systems C3H4O and C3H3O
Authors: Chin Chih-Hao , Chaudhuri Chanchal , Lee Shih-Huang
Published: July 2011

We investigated the dynamics of photodissociation of propenal (acrolein, CH2CHCHO) at 157 nm in a molecular beam and of migration and elimination of hydrogen atoms in systems C3H4O and C3H3O using quantum-chemical calculations. Compared with the previous results of photodissociation of propenal at 193 nm, the major difference is that the C3H3O fragment present at the 193-nm photolysis disappears at the 157-nm photolysis whereas the C3H2O fragment absent at 193 nm appears at 157 nm. Optimized structures and harmonic vibrational frequencies of molecular species with gross formula C3H2–4O were computed at the level of B3LYP/6-311G(d,p) and total energies of those molecules at optimized structures were computed at the level of CCSD(T)/6-311+G(3df,2p). Based on the calculated potential-energy surfaces, we deduce that the C3H3O fragment observed in the photolysis of propenal at 193 nm is probably CHCCHOH (2A″) and/or CH2CCOH (2A″) produced from an intermediate hydroxyl propadiene (CH2CCHOH) following isomerization. Adiabatic and vertical ionization potentials of eight isomers of C3H3O and two isomers of C3H2O were calculated; CHCCHOH (2A″) and CH2CCOH (2A″) have ionization potentials in good agreement with the experimental value of ∼7.4 eV. We also deduce that all the nascent C3H3O fragments from the photolysis of propenal at 157 nm spontaneously decompose mainly to C2H3 + CO and C3H2O + H because of the large excitation energy. This work provides profound insight into the dynamics of migration and elimination of hydrogen atoms of propenal optically excited in the vacuum-ultraviolet region.
On the effectiveness of CCSD(T) complete basis set extrapolations for atomization energies
Authors: Feller David , Peterson Kirk A. , Grant Hill J.
Published: July 2011

The leading cause of error in standard coupled cluster theory calculations of thermodynamic properties such as atomization energies and heats of formation originates with the truncation of the one-particle basis set expansion. Unfortunately, the use of finite basis sets is currently a computational necessity. Even with basis sets of quadruple zeta quality, errors can easily exceed 8 kcal/mol in small molecules, rendering the results of little practical use. Attempts to address this serious problem have led to a wide variety of proposals for simple complete basis set extrapolation formulas that exploit the regularity in the correlation consistent sequence of basis sets. This study explores the effectiveness of six formulas for reproducing the complete basis set limit. The W4 approach was also examined, although in lesser detail. Reference atomization energies were obtained from standard coupled-cluster singles, doubles, and perturbative triples (CCSD(T)) calculations involving basis sets of 6ζ or better quality for a collection of 141 molecules. In addition, a subset of 51 atomization energies was treated with explicitly correlated CCSD(T)-F12b calculations and very large basis sets. Of the formulas considered, all proved reliable at reducing the one-particle expansion error. Even the least effective formulas cut the error in the raw values by more than half, a feat requiring a much larger basis set without the aid of extrapolation. The most effective formulas cut the mean absolute deviation by a further factor of two. Careful examination of the complete body of statistics failed to reveal a single choice that out performed the others for all basis set combinations and all classes of molecules.
Nonplanar ion-acoustic solitary waves with superthermal electrons in warm plasma
Authors: Eslami Parvin , Mottaghizadeh Marzieh , Pakzad Hamid Reza
Published: July 2011

In this paper, we consider an unmagnetized plasma consisting of warm adiabatic ions, superthermal electrons, and thermal positrons. Nonlinear cylindrical and spherical modified Korteweg–de Vries (KdV) equations are derived for ion acoustic waves by using reductive perturbation technique. It is observed that an increasing positron concentration decreases the amplitude of the waves. Furthermore, the effects of the superthermal parameter (k) on the ion acoustic waves are found.
Proximity effect in electron-doped cuprate Josephson junctions
Authors: Charpentier S. , Roberge G. , Godin-Proulx S. , Fournier P.
Published: July 2011

We study the proximity effect in Josephson junctions made of electron-doped cuprates Pr2–xCexCuO4 (PCCO). With superconducting electrodes at a fixed doping x = 0.15, we explore the variation of the Josephson coupling with the doping and the thickness of the barrier. We observe Josephson coupling for any type of barrier: antiferromagnetic (AF) metal, AF insulator, or paramagnetic metal. For an x = 0.05 barrier, we can estimate the normal coherence length, ξn = 12 ± 3 nm. Comparing this value with the theoretical prediction, ξn,max = 4.5 nm, we conclude that the proximity effect through a barrier of PCCO x = 0.05 is stronger than expected.
Analytical blowup solutions to the 2-dimensional isothermal Euler-Poisson equations of gaseous stars II
Authors: Yuen Manwai
Published: July 2011

In this article, we construct analytical blowup solutions with non-radial symmetry for the 2-dimensional Euler-Poisson equations. Based on the previous solutions with radial symmetry for the 2-dimensional isothermal Euler-Poisson equations, some special blowup solutions with non-radial symmetry are constructed by the separation method.
Sinking of small sphere at low Reynolds number through interface
Authors: Lee Duck-Gyu , Kim Ho-Young
Published: July 2011

A dense solid sphere gently released on an air-liquid interface slowly sinks into liquid due to gravity, while the motion is resisted by viscous and capillary forces. Here, we predict the sinking velocity of the interface-straddling sphere by a simplified model and experimentally corroborate the results. The viscous drag on the sphere is determined by integrating the surface stress, which is the solution of the Stokes equation, over the wetted area that changes with time. To compute the interfacial tension force that depends on the meniscus profile, we solve the dynamic boundary condition for the normal and tangential stresses at the air-liquid interface. The predicted sinking velocity, a function of the sphere density and radius, liquid density, viscosity and surface tension, and the dynamic contact angle, is in good agreement with the experimental measurements except for the late stages when meniscus snapping occurs. We also construct a scaling law for the steady velocity of a sinking sphere, which gives the characteristic sinking time.
Capacitive carbon nanotube networks in polymer composites
Authors: Ding Ji-Jia , Lu Chieh-Lien , Hsu Wen-Kuang
Published: July 2011

Carbon nanotube networks behave as capacitive elements in polymers and carrier transport across tube junctions resembles charging a capacitive tube/polymer/tube structure. Spin localization at interface is verified by electron paramagnetic resonance and a transport mechanism based on temperature controlled free volume of polymer is proposed.
Coplanar waveguide on graphene in the range 40 MHz–110 GHz
Authors: Dragoman M. , Neculoiu D. , Cismaru A. , Muller A. A. , Deligeorgis G. , Konstantinidis G. , Dragoman D. , Plana R.
Published: July 2011

We present the modeling and measurements of microwave propagation in a coplanar waveguide over graphene in the range of frequencies 40 MHz-110 GHz, which suggest that graphene could work well in a very large bandwidth. Graphene is acting as a natural matching device because its equivalent resistance at these frequencies is able to vary more than 75% when DC biases are applied in the range −4 V to 4 V on the graphene waveguide.
Modifying electronic transport properties of graphene by electron beam irradiation
Authors: He Y. H. , Wang L. , Chen X. L. , Wu Z. F. , Li W. , Cai Y. , Wang N.
Published: July 2011

We demonstrate that electron beam irradiation with precise dosage control under clean vacuum conditions can induce bond disorder and inter-valley scattering but not necessarily lattice damage in high quality single-layer graphene, as evidenced by the changes of temperature-dependent transport properties, quantum Hall effects, and large negative magnetoresistance effects observed at cryogenic temperatures. The bond disorder significantly modified the Raman scattering and electronic transport properties of graphene, which is consistent with that observed in hydrogenated graphene. In situ transport measurements at different sample treatment stages revealed an interesting activation process of graphene through electron beam irradiation. The activated graphene samples are very sensitive to oxygen and water vapors.
Investigation of the magnetic field effects on electron mobility in tri-(8-hydroxyquinoline)-aluminum based light-emitting devices
Authors: Peng Qiming , Sun Jixiang , Li Xianjie , Li Mingliang , Li Feng
Published: July 2011

We investigated the magnetic field effects (MFEs) on electron mobility in tri-(8-hydroxyquinoline)-aluminum based light-emitting devices by the transient electroluminescence (EL) method upon application of various offset voltages (Voffset). It is found that the rising edges of the EL overlap closely but the falling edges are separated by the magnetic field both when Voffset = 0 V and Voffset > Vturnon. The results suggest the bipolaron model and the triplet-polaron interaction model related to the carriers’ mobility are not the dominant mechanisms for explaining the MFEs under our experimental conditions, and the external magnetic field is confirmed to affect the carriers’ recombination process.
Modeling of the spin-transfer torque switching in FePt/MgO-based perpendicular magnetic tunnel junctions: A combined ab initio and micromagnetic simulation study
Authors: Zhu Wanjiao , Liu Yaowen , Duan Chun-Gang
Published: July 2011

Combined ab initio and micromagnetic simulations are carried out to build up a direct relationship between critical switching current Jc and geometric structure (in-plane lattice constant a and film thickness) of FePt in magnetic tunnel junctions. Ab initio calculations predict that the strain effect can significantly influence the uniaxial magnetic anisotropy constant Ku, whereas the thickness has less significant impact on Ku. Micromagnetic simulations show that Jc linearly increases with the increasing Ku (the decreasing a) and the switching time decreases with the increasing current at a fixed Ku and is sensitive to the perpendicular spin-torque factor at negative current.
Strontium vacancy clustering in Ti-excess SrTiO3 thin film
Authors: Tokuda Y. , Kobayashi S. , Ohnishi T. , Mizoguchi T. , Shibata N. , Ikuhara Y. , Yamamoto T.
Published: July 2011

The defect structure of a homoepitaxial thin film of SrTiO3 containing excess Ti grown by pulsed laser deposition is investigated. The Sr/Ti ratio of the film is controlled to possess a slight excess of Ti by tuning the laser fluence. High-resolution transmission electron microscopy and electron energy loss spectroscopy studies reveal that the film contains Sr vacancies because of the presence of excess Ti. These vacancies tend to cluster as platelets several nanometers in diameter on (001) planes in the films. The SrO planes that contain the vacancy clusters exhibit lattice expansion due to Coulomb repulsion.
Compound FDTD method for silicon photonics
Authors: Olyaee Abbas , Hamadani Farzad T.
Published: July 2011

Attempt to manufacture photonics devices on silicon requires theoretical and numerical prediction. This essay presents Compound FDTD (C-FDTD) method for comprehensive simulation of silicon photonics devices. Although this method is comprehensive, it maintains conventional Yee algorithm. The method involves variation of refractive index due to nonlinear effects. With the help of this simulator, refractive index change due to free-carriers created through two photon absorption and Kerr effect in silicon waveguide is considered. Results indicate how to choose pump pulse shape to optimum operation of active photonics devices. Also conductivity variation of Si waveguide due to change in free-carrier density is studied. By considering variations in conductivity profile, we are able to design better schemes for sweep free carriers away with reverse bias or nonlinear photovoltaic effect for fast devices and Raman amplifiers.
Lower hybrid current drive at high density in Alcator C-Mod
Authors: Wallace G.M. , Hubbard A.E. , Bonoli P.T. , Faust I.C. , Harvey R.W. , Hughes J.W. , LaBombard B.L. , Meneghini O. , Parker R.R. , Schmidt A.E. , Shiraiwa S. , Smirnov A.P. , Whyte D.G. , Wilson J.R. , Wright J.C. , Wukitch S.J.
Published: July 2011

Experimental observations of lower hybrid current drive (LHCD) at high density on the Alcator C-Mod tokamak are presented in this paper. Bremsstrahlung emission from relativistic fast electrons in the core plasma drops suddenly above line-averaged densities of 1020 m−3 (ω/ωLH ∼ 3) in single null discharges with large (⩾8 mm) inner gaps, well below the density limit previously observed on limited tokamaks (ω/ωLH ∼ 2). Modelling and experimental evidence suggest that the absence of LHCD driven fast electrons at high density may be due to parasitic collisional absorption in the scrape-off layer (SOL). Experiments show that the population of fast electrons produced by LHCD at high density (
) can be increased by operating with an inner gap of less than ∼5 mm with the strongest non-thermal emission in inner wall limited plasmas. A change in plasma topology from single to double null produces a modest increase in non-thermal emission at high density. Increasing the electron temperature in the periphery of the plasma (0.8 > r/a > 1.0) also results in a modest increase in non-thermal electron emission above the density limit. Ray tracing/Fokker–Planck simulations of these discharges predict the observed sensitivity to plasma position when the effects of collisional absorption in the SOL are included in the model.