bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating beyond the human machinery: A closer look at accident causation in high hazard industries
Authors: Mackenzie Cheryl , Holmstrom Don
Published: December 2008

Human error is not a cause of an accident—it's a symptom of underlying problems. Attempting to modify operator behavior to prevent human error will not rectify those underlying problems nor will it prevent major catastrophic accidents. This article will provide evidence to support why an organization's safety focus should not be solely on behavior‐based safety. It will demonstrate how an equal emphasis and focus needs to be placed on the safety systems of the organization, as these aspects of safety provide a more accurate assessment of a company's true safety state. By taking another look at the US Chemical Safety Board's completed investigations, this article will demonstrate how one must go beyond the actions and decisions of frontline operators to truly understand the causes of any given incident and to safeguard against major accident hazards. © 2008 American Institute of Chemical Engineers Process Saf Prog, 2009
Effect of structural parameters of peptides on dimer formation and highly oxidized side products in the oxidation of thiols of linear analogues of human β‐defensin 3 by DMSO
Authors: Liu Shouping , Zhou Lei , Chen Liyan , Dastidar Shubhra Ghosh , Verma Chandra , LI Jing , Tan Donald , Beuerman Roger
Published: December 2008

The purpose of this study was to examine the effects of structural parameters of peptides on their oxidation by DMSO, including location of cysteine, effect of adjunct group participation, molecular hydrophobicity, steric hindrance or the accessibility of thiol group and peptide conformation, on oxidation rates, dimer formation and associated side products. We designed and synthesized two series of linear cysteine‐containing analogues of human β‐defensin 3 (the C1‐peptides with cysteine at the N‐terminus residue 1, the C29‐peptides with cysteine located at residue 29 in the centre of peptide), which were used for preparation of disulphide‐linked homodimers. HPLC–ESI–MS was used to monitor the oxidation process and to characterize the molecular weights of dimers and side products of high oxidation. The formations of dimers and side products were dependent on the position of cysteines. Hydrophobicity generally rendered the thiol groups less accessible and hence exposed them to slow oxidation to form dimers (or even fail to form dimers during the timescale of observation). Molecular dynamics simulations showed that the exposure of cysteines (and sulphurs) of the C1‐peptides was much larger than for the C29‐peptides. The larger hydrophobic side chains tended to enable clustering of the side chains that sequester cysteine, particularly in the C29‐peptides, which provided a molecular explanation for the observed trends in oxidation rates. Together with molecular modelling, we propose a reaction mechanism to elucidate the oxidation results of these peptides. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.
Expectation value averages of size consistent hermitian operators and the definition of Fukui functions
Authors: Carbó‐Dorca Ramon , Gallegos Ana
Published: December 2008

The Ayers expectation value of size consistent operator averages is analyzed, leading to a general description of Fukui functions in terms of a possibly multidimensional gradient. The expectation value involves the density of an arbitrary collective of chosen ions or excited states. Molecular Orbital (MO) densities and Fukui functions are proved to be connected through the gradient of the first order state density functions with respect to the MO occupation numbers. The mathematical development taken as a whole opens the way to a general framework, where Fukui functions arise as a general theoretical tool to study molecular reactivity. Finally, shape functions appear as a plausible link between Ayers framework and the general ideas presented in this study. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Using second‐order generalized estimating equations to model heterogeneous intraclass correlation in cluster‐randomized trials
Authors: Crespi Catherine M. , Wong Weng Kee , Mishra Shiraz I.
Published: December 2008

In cluster‐randomized trials, it is commonly assumed that the magnitude of the correlation among subjects within a cluster is constant across clusters. However, the correlation may in fact be heterogeneous and depend on cluster characteristics. Accurate modeling of the correlation has the potential to improve inference. We use second‐order generalized estimating equations to model heterogeneous correlation in cluster‐randomized trials. Using simulation studies we show that accurate modeling of heterogeneous correlation can improve inference when the correlation is high or varies by cluster size. We apply the methods to a cluster‐randomized trial of an intervention to promote breast cancer screening. Copyright © 2008 John Wiley & Sons, Ltd.
Experiments on free-surface turbulence
Authors: SAVELSBERG RALPH , VAN DE WATER WILLEM
Published: December 2008

We study the free surface of a turbulent flow, in particular the relation between the statistical properties of the wrinkled surface and those of the velocity field beneath it. Channel flow turbulence is generated using an active grid. Through a judicial choice of the stirring protocol the anisotropy of the subsurface turbulence can be controlled. The largest Taylor Reynolds number obtained is Reλ = 258. We characterize the homogeneity and isotropy of the flow and discuss Taylor's frozen turbulence hypothesis, which applies to the subsurface turbulence but not to the surface. The surface gradient field is measured using a novel laser-scanning device. Simultaneously, the velocity field in planes just below the surface is measured using particle image velocimetry (PIV). Several intuitively appealing relations between the surface gradient field and functionals of the subsurface velocity field are tested. For an irregular flow shed off a vertical cylinder, we find that surface indentations are strongly correlated with both vortical and strain events in the velocity field. For fully developed turbulence this correlation is dramatically reduced. This is because the large eddies of the subsurface turbulent flow excite random capillary–gravity waves that travel in all directions across the surface. Therefore, the turbulent surface has dynamics of its own. Nonetheless, it does inherit both the integral scale, which determines the predominant wavelength of the capillary–gravity surface waves, and the (an)isotropy from the subsurface turbulence. The kinematical aspects of the surface–turbulence connection are illustrated by a simple model in which the surface is described in terms of waves originating from Gaussian wave sources that are randomly sprinkled on the moving surface.
Galerkin representations and fundamental solutions for an axisymmetric microstretch fluid flow
Authors: SHERIEF H. H. , FALTAS M. S. , ASHMAWY E. A.
Published: December 2008

The method of associated matrices is used to obtain Galerkin type representations. Fundamental solutions are then obtained for the cases of a point body couple and a point microstretch force. A formula for calculating the total couple acting on a rigid body rotating axi-symmetrically in a microstretch fluid is deduced. A generalized reciprocal theorem is deduced. An application for a rigid sphere rotating in a microstretch fluid is discussed. The results of the application are represented graphically.
The measurement of growth rates in capillary jets
Authors: GONZÁLEZ H. , GARCÍA F. J.
Published: December 2008

The growth of perturbations on a capillary jet issuing from a circular nozzle in the Rayleigh regime is experimentally investigated. Electrohydrodynamic sinusoidal stimulation is employed to this end, along with two independent methods to obtain growth rates of the linear regime with the best accuracy so far. The first method exploits the correlation between the stimulation voltage and the breakup time measured with the help of stroboscopic images of the jet. The second method is an analysis of the spatial evolution of perturbations through a local jet-shadow-width photometry, with careful avoidance of the initial transient and the final nonlinear stages. Experiments conducted with ink allow the application of both methods, as the liquid is opaque. They give consistent results, with very small statistical errors, with respect to the expected theoretical dispersion relation, once the dynamic surface tension is adjusted. The adjusted value is in accordance with an estimate made from drop-dynamics experiments also reported here. By dealing with a simpler liquid (aqueous solution of NaNO3), we are able to compare results from the first method against the theoretical predictions without adjustment of any parameter. The agreement is again excellent. Possible sources of systematic errors in this kind of measurements are identified and procedures for avoiding them are designed.
Helical structure of longitudinal vortices embedded in turbulent wall-bounded flow
Authors: VELTE CLARA M. , HANSEN MARTIN O. L. , OKULOV VALERY L.
Published: December 2008

Embedded vortices in turbulent wall-bounded flow over a flat plate, generated by a passive rectangular vane-type vortex generator with variable angle β to the incoming flow in a low-Reynolds-number flow (Re = 2600 based on the inlet grid mesh size L = 0.039 m and free stream velocity U∞ = 1.0 ms−1), have been studied with respect to helical symmetry. The studies were carried out in a low-speed closed-circuit wind tunnel utilizing stereoscopic particle image velocimetry (SPIV). The vortices have been shown to possess helical symmetry, allowing the flow to be described in a simple fashion. Iso-contour maps of axial vorticity revealed a dominant primary vortex and a weaker secondary one for 20° ≤ β ≤ 40°. For angles outside this range, the helical symmetry was impaired due to the emergence of additional flow effects. A model describing the flow has been utilized, showing strong concurrence with the measurements, even though the model is decoupled from external flow processes that could perturb the helical symmetry. The pitch, the vortex core size, the circulation and the advection velocity of the vortex all vary linearly with the device angle β. This is important for flow control, since one thereby can determine the axial velocity induced by the helical vortex as well as the swirl redistributing the axial velocity component for a given device angle β. This also simplifies theoretical studies, e.g. to understand and predict the stability of the vortex and to model the flow numerically.
Yine
Authors: Sebastián Rittma Urquía , Marlett Stephen A.
Published: December 2008

Yine [ˈjine] (previously known as Piro, ISO 639-3 = pib) is a Maipuran language (Payne 1991, Campbell 1997, Solís Fonseca 2003). See Payne (1991) and Campbell (1997) for discussion of the relationship of the Maipuran (or Maipurean) languages to the controversial Arawakan stock. There are approximately 3,000 speakers of Yine in the Peruvian Amazon. People in Brazil and Bolivia known as Manchineri (alternative spellings exist; ISO 639-3 = mpd) also speak a dialect of Yine (Urquía Sebastián 2006a).
Pulmonic ingressive phonation: Diachronic and synchronic characteristics, distribution and function in animal and human sound production and in human speech
Authors: Eklund Robert
Published: December 2008

This paper looks at the phenomenon of ingressive speech, i.e. speech produced on a pulmonic ingressive airstream, set in the context of human and animal ingressive phonation. The literature on ingressive speech and phonation spanning several centuries is reviewed, as well as contemporary reports of their incidence and characteristics from both functional and acoustic perspectives. Ingressive phonation has been used as a deliberate means of speech or sound production for hundreds of years in order to achieve specific effects, and it is still used for the same purposes, by e.g. shamans and ventriloquists. In normal spoken conversation – contrary to what is often claimed – present-day ingressive speech is not limited to Scandinavia or Nordic languages, but is found on all continents, in genetically unrelated languages. Where ingressive speech occurs, it serves more or less the same paralinguistic functions, such as a feedback marker in a dialog. Since pulmonic ingressive phonation is also common in the calls of monkeys and apes, thus exhibiting a biological basis, it is suggested that ingressive speech might constitute a neglected universal phenomenon, rather than being highly marked, which is how it is commonly described in the literature.
Set shifting and reversal learning in patients with bipolar disorder or schizophrenia
Authors: McKirdy J. , Sussmann J. E. D. , Hall J. , Lawrie S. M. , Johnstone E. C. , McIntosh A. M.
Published: December 2008

Background

Bipolar disorder and schizophrenia have both been associated with deficits in extra-dimensional set shifting (EDS). Deficits in reversal learning (RL) have also been shown in schizophrenia but not in bipolar disorder. This study sought to assess the specificity of these findings in a direct comparison of clinically stable patients with each disorder.

Method

The intra-dimensional/extra-dimensional (IDED) set-shifting task, part of the Cambridge Neuropsychological Test Automated Battery (CANTAB), was administered to 30 patients with schizophrenia, 47 with bipolar disorder and a group of 44 unaffected controls. EDS and RL errors were compared between the groups and related to measures of current and past psychiatric symptoms and medication.

Results

Both groups of patients with schizophrenia or bipolar disorder made more EDS and RL errors than controls. Neither measure separated the two disorders, even when the analysis was restricted to euthymic patients. No relationship was found with prescribed medication.

Conclusions

Patients with bipolar disorder or schizophrenia show common deficits in EDS and RL. These deficits do not seem to be attributable to current symptoms and are consistent with disrupted networks involving the ventral prefrontal cortex.
Is adult attention deficit hyperactivity disorder a valid diagnosis in the presence of high IQ?
Authors: Antshel K. M. , Faraone S. V. , Maglione K. , Doyle A. , Fried R. , Seidman L. , Biederman J.
Published: December 2008

Background

Because the diagnosis of attention deficit hyperactivity disorder (ADHD) in higher education settings is rapidly becoming a contentious issue, particularly among patients with high IQs, we sought to assess the validity of diagnosing ADHD in high-IQ adults and to further characterize the clinical features associated with their ADHD.

Method

We operationalized high IQ as having a full-scale IQ⩾120. We identified 53 adults with a high IQ who did not have ADHD and 64 adults with a high IQ who met diagnostic criteria for ADHD. Groups did not differ on IQ, socio-economic status or gender.

Results

High-IQ adults with ADHD reported a lower quality of life, had poorer familial and occupational functioning, and had more functional impairments, including more speeding tickets, accidents and arrests. Major depressive disorder, obsessive-compulsive disorder and generalized anxiety disorder diagnoses were higher in high-IQ adults with ADHD. All other psychiatric co-morbidities, including antisocial personality disorder and substance abuse, did not differ between the two high-IQ groups. ADHD was more prevalent in first-degree relatives of adults with ADHD relative to controls.

Conclusions

Our data suggest that adults with ADHD and a high IQ display patterns of functional impairments, familiality and psychiatric co-morbidities that parallel those found in the average-IQ adult ADHD population.
Word and pseudoword superiority effects in Italian–English bilinguals
Authors: GROSSI GIORDANA , MURPHY JEREMY , BOGGAN JOSH
Published: December 2008

Two indices of automatic orthographic processing, the word and pseudoword superiority effects, were explored in native Italian speakers familiar with English (late learners) and native English-speaking controls unfamiliar with Italian. Participants performed a forced-choice letter identification task with five categories of words: Italian words and pseudowords, English words and pseudowords, and nonwords. Native Italian speakers showed superiority effects for both languages, whereas English-speaking controls showed superiority effects only for English. These results suggest that orthographic processing can become automatic with extensive training in late bilinguals.
Cross-linguistic differences and their impact on L2 sentence processing
Authors: JACKSON CARRIE N. , DUSSIAS PAOLA E.
Published: December 2008

Using a self-paced reading task, the present study investigates how highly proficient second language (L2) speakers of German with English as their native language process unambiguous wh-subject-extractions and wh-object-extractions in German. Previous monolingual research has shown that English and German exhibit different processing preferences for the type of wh-question under investigation, due in part to the robust case-marking system in German – a morphosyntactic feature that is largely absent in English (e.g., Juffs and Harrington, 1995; Fanselow, Kliegl and Schlesewsky 1999; Meng and Bader, 2000; Juffs, 2005). The results revealed that the L2 German speakers utilized case-marking information and exhibited a subject-preference similar to German native speakers. These findings are discussed in light of relevant research regarding the ability of L2 speakers to adopt native-like processing strategies in their L2.
Bilingualism as a window into the language faculty: The acquisition of objects in French-speaking children in bilingual and monolingual contexts
Authors: PÉREZ-LEROUX ANA T. , PIRVULESCU MIHAELA , ROBERGE YVES
Published: December 2008

Where do the two languages of the bilingual child interact? The literature has debated whether bilingual children have delays in the acquisition of direct objects. The variety of methods and languages involved have prevented clear conclusions. In a transitivity-based approach, null objects are a default structural possibility, present in all languages. Since the computation of lexical and syntactic transitivity depends on lexical acquisition, we propose a default retention hypothesis, predicting that bilingual children retain default structures for aspects of syntactic development specifically linked to lexical development (such as objects). Children acquiring French (aged 3;0–4;2, N = 34) in a monolingual context and a French/English bilingual context participated in a study eliciting optional and obligatory direct objects. The results show significant differences between the rates of omissions in the two groups for both types of objects. We consider two models of how the bilingual lexicon may determine the timetable of development of transitivity.
Prevalence and sociodemographic risk factors related to household food security in Aboriginal peoples in Canada
Authors: Willows Noreen D , Veugelers Paul , Raine Kim , Kuhle Stefan
Published: December 2008

Objective

Canada’s Aboriginal population is vulnerable to food insecurity and increasingly lives off-reserve. The Canadian Community Health Survey, Cycle 2.2 Nutrition, was used to compare the prevalence and sociodemographic correlates of food insecurity between non-Aboriginal and off-reserve Aboriginal households.

Design

Food insecurity status was based on Health Canada’s revised interpretation of responses to the US Household Food Security Survey Module. Logistic regression was used to assess if Aboriginal households were at higher risk for food insecurity than non-Aboriginal households, adjusting for household sociodemographic factors.

Setting

Canada.

Subjects

Households (n35,107), 1528 Aboriginal and 33 579 non-Aboriginal.

Results

Thirty-three per cent of Aboriginal households were food insecure as compared with 9 % of non-Aboriginal households (univariate OR 5·2, 95 % CI 4·2, 6·3). Whereas 14 % of Aboriginal households had severe food insecurity, 3 % of non-Aboriginal households did. The prevalence of sociodemographic risk factors for household food insecurity was higher for Aboriginal households. Aboriginal households were more likely to have three or more children (14 %v. 5 %), be lone-parent households (2 1 %v. 5 %), not have home ownership (52 %v. 31 %), have educational attainment of secondary school or less (43 %v. 26 %), have income from sources other than wages or salaries (38 %v. 29 %), and be in the lowest income adequacy category (33 %v. 12 %). Adjusted for these sociodemographic factors, Aboriginal households retained a higher risk for food insecurity than non-Aboriginal households (OR 2·6, 95 % CI 2·1, 3·2).

Conclusions

Off-reserve Aboriginal households in Canada merit special attention for income security and poverty alleviation initiatives.
Vitamin D status of Year 3 children and supplementation through schools with fortified milk
Authors: Graham David , Kira Geoff , Conaglen John , McLennan Stephanie , Rush Elaine
Published: December 2008

Objective

To evaluate levels of vitamin D3and HDL-cholesterol (HDL-C), and the ratio of HDL-C to LDL-cholesterol (LDL-C), in schoolchildren receiving vitamin-D-fortified, fat-depleted, high-Ca milk in schools.

Design

Cross-sectional study of previously randomised schools receiving supplemental milk, compared with a matched control group.

Setting

Low-decile Year 1–6 schools in the Waikato region of New Zealand.

Subjects

Year 3 children from either milk schools or control schools, consenting to blood sampling.

Results

For eighty-nine children receiving supplementary daily milk, vitamin D3levels were significantly higher than in eighty-three control children matched for age, sex, body composition and ethnicity (mean (sd): 49·6 (15·8)v. 43·8 (14·7) nmol/l,P= 0·011), as were HDL-C levels (mean (sd): 1·47 (0·35)v. 1·35 (0·29) mmol/l,P= 0·024) and HDL-C:LDL-C (median: 0·79v. 0·71,P= 0·026). LDL-C levels were similar in both groups (mean (sd): 2·07 (0·55)v. 2·16 (0·60) mmol/l,P= 0·31). Of control children, 32/83 (20·2 %) of the milk group (Pearson’sχ2= 7·00,P= 0·008). Mean 25-hydroxyvitamin D (vitamin D3) levels in the milk group were still below the lower end of the recommended normal range (60 nmol/l).

Conclusions

Vitamin D3levels are low in low-decile Year 3 children in midwinter. Levels are improved with vitamin-D-fortified milk but still below the recommended range. HDL-C and HDL-C:LDL-C levels are improved in the milk-supplemented group. This supports the supply of vitamin-D-fortified, fat-reduced milk to schools.
Community-specific modifications are essential for objective assessment of maternal dietary intake – Pune Maternal Nutrition Study
Authors: Rao S , Kanade AN , Joshi SR , Yajnik CS
Published: December 2008

Objective

To introduce community-specific modifications in the conventional 24 h recall method for objectively estimating maternal dietary intake and validate it with a reference method.

Design

A modified 24 h recall method was developed with the visit of trained local girls at the subject’s home to weigh portion sizes at each mealtime over the 24 h recall period. This was validated with the reference method in which weighed records of the foods consumed were obtained and their laboratory analysis was done to obtain nutrient intakes.

Setting

Rural areas located 40–50 km from Pune City, India.

Subjects

Forty-one pregnant women participated willingly.

Results

The estimates of intake obtained from the reference method were comparable to those obtained from the modified 24 h recall method for energy (7795 (sd1841) kJ (1863 (sd440) kcal)v. 7615 (sd1824) kJ (1820 (sd436) kcal), respectively), protein (48·6 (sd12·9) gv. 45·3 (sd12·6) g, respectively) and fat (35·3 (sd16·6) gv. 36·0 (sd14·2) g, respectively). Significant correlation was observed between the estimates obtained by the two methods for energy (0·75,P< 0·001), protein (0·71,P< 0·001) and fat (0·56,P< 0·001) and differences in nutrient intake did not reveal any systematic bias. When compared with the reference method, the modified method showed >80 % sensitivity and specificity for identifying inadequate maternal energy intakes.

Conclusions

Simple modifications to conventional methods backed by understanding of community specifics and nutritional peculiarities are of immense importance in obtaining objective estimates of daily nutritional intakes of individuals in free-living populations. The approach would be adaptable in similar settings in other developing countries.
Styles of extension offshore mid‐Norway and implications for mechanisms of crustal thinning at passive margins
Authors: Osmundsen P. T. , Ebbing J.
Published: December 2008

Eocene magmatic breakup along the mid‐Norway rifted margin was preceded by extreme Jurassic‐Cretaceous crustal thinning in a magma‐poor environment. Along the SE borders of the rift, “top basement” detachment faults with heaves on the order of 15–40 km evolved in at least two stages to become the boundaries between moderately thinned (20–30 km thick) crust and a 100–200 km wide, highly extended area with crustal thicknesses generally between 2 and 12 km under the present‐day Møre and Vøring basins. In the footwalls of the basin flank detachments, lower and middle crust was exhumed in extensional domes that became incised by a younger set of normal faults. Under the most highly thinned areas, a more distal set of deep‐seated (basin floor) detachments incised and extended remnant crust and, probably, the upper mantle, leaving as little as <5 km of continental crust to be preserved under thick synrift and postrift deposits. We suggest that basin flank detachments such as the ones described above hold the potential to reduce the crustal thickness down to the critical value required for embrittlement of continental crust. Thus, they prepare the ground for incision by the basin floor detachments, which may become responsible for exhumation of deep crust or continental mantle if extension is allowed to proceed.
Role of fluids in the initiation of the 2008 Iwate earthquake (M7.2) in northeast Japan
Authors: Wang Zhi , Fukao Yoshio , Kodaira Shuichi , Huang Runqiu
Published: December 2008

Seismic velocity (Vp, Vs) and Poisson's ratio (σ) images show that the hypocenter of the 2008 Iwate‐Miyagi earthquake (M7.2) is located in a distinctive zone with low‐Vp, slightly low‐Vs and low‐σ within the upper 10 km depths, where the mechanical strength might be weaker than the normal seismogenic layer with high velocity and low Poisson's ratio immediate below. A prominent low‐Vp, low‐Vs and high‐σ zone is revealed in the lower crust and uppermost mantle under the Iwate mainshock hypocenter, which may reflect fluids resulting from the dehydration of the subducting Pacific slab under northeast Japan. The aqueous component of fluids intruded into the source region may have reduced the mechanical strength of the rock matrix and so triggered the Iwate earthquake. Our results indicate that crustal fluids beneath the seismogenic layer can play an important role in the initiation of large crustal earthquakes.
Statistical study of polar distribution of mesoscale field‐aligned currents
Authors: Hasunuma T. , Nagatsuma T. , Kataoka R. , Takahashi Y. , Fukunishi H. , Matsuoka A. , Kumamoto A.
Published: December 2008

Field‐aligned currents (FACs) play an important role in the magnetosphere‐ionosphere coupling system for transporting electromagnetic energy. Although large‐scale region 1 (R1) and region 2 (R2) FACs have been statistically investigated for a few decades, there have been relatively fewer investigations of the fundamental characteristics of mesoscale (ranging from about 10 to 100 km) FACs and the relationship between them and large‐scale FACs. Here we report some fundamental characteristics of mesoscale FACs on the basis of a statistical analysis using long‐term Akebono satellite data from March 1989 to December 1996. We found that the current density of mesoscale FACs with a spatial scale of 10–80 km at ionospheric altitude is on average the largest in the dayside region of 75°–82° in corrected geomagnetic latitude and 0600–1500 in corrected geomagnetic local time. The current density is especially enhanced under the sunlit condition in summer. The intensities and distributions of mesoscale FACs change with interplanetary magnetic field conditions. We also found altitude dependence of mesoscale FACs for the first time. Current densities of mesoscale FACs gradually increase with the altitude. Mesoscale FACs tend to distribute in the R1 current region, and the current density in the morning to noon sector (downward R1 FAC region) is stronger than that in the noon to evening sector (upward R1 FAC region). Further, the seasonal variations of mesoscale FACs correspond to those of large‐scale FACs on the dayside but areopposite to those of large‐scale FACs on the nightside.
Radiative impact of mixing state of black carbon aerosol in Asian outflow
Authors: Shiraiwa M. , Kondo Y. , Moteki N. , Takegawa N. , Sahu L. K. , Takami A. , Hatakeyama S. , Yonemura S. , Blake D. R.
Published: December 2008

The radiative impact of the mixing state of black carbon (BC) aerosol is investigated in Asian outflow. The mixing state and size distribution of BC aerosol were measured with a ground‐based single‐particle soot photometer at a remote island (Fukue) in Japan in spring 2007. The mass concentration of BC in Asian continental air masses reached 0.5 μg m−3, with a mass median diameter of 200–220 nm. The median value of the shell/core diameter ratio increased to ∼1.6 in Asian continental and maritime air masses with a core diameter of 200 nm, while in free tropospheric and Japanese air masses it was 1.3–1.4. On the basis of theoretical calculations using the size distribution and mixing state of BC aerosol, scattering and absorption properties of PM1 aerosols were calculated under both dry and ambient conditions, considering the hygroscopic growth of aerosols. It was estimated that internal mixing enhanced the BC absorption by a factor of 1.5–1.6 compared to external mixing. The calculated absorption coefficient was 2–3 times higher in Asian continental air masses than in clean air. Coatings reduced the single‐scattering albedo (SSA) of PM1 aerosol by 0.01–0.02, which indicates the importance of the mixing state of BC aerosol in evaluating its radiative influence. The SSA was sensitive to changes in air mass type, with a value of ∼0.98 in Asian continental air masses and ∼0.95 in Japanese and free tropospheric air masses under ambient conditions.
Systems Biology Markup Language (SBML) Level 2: Structures and Facilities for Model Definitions
Authors: Hucka Michael , Hoops Stefan , Keating Sarah , Le Novère Nicolas , Sahle Sven , Wilkinson Darren
Published: December 2008

With the rise of Systems Biology as a new paradigm for understanding biological processes, the development of quantitative models is no longer restricted to a small circle of theoreticians. The dramatic increase in the number of these models precipitates the need to exchange and reuse both existing and newly created models. The Systems Biology Markup Language (SBML) is a free, open, XML-based format for representing quantitative models of biological interest that advocates the consistent specification of such models and thus facilitates both software development and model exchange.Principally oriented towards describing systems of biochemical reactions, such as cell signalling pathways, metabolic networks and gene regulation etc., SBML can also be used to encode any kinetic model. SBML offers mechanisms to describe biological components by means of compartments and reacting species, as well as their dynamic behaviour, using reactions, events and arbitrary mathematical rules. SBML also offers all the housekeeping structures needed to ensure an unambiguous understanding of quantitative descriptions.This is Release 1 of the specification for SBML Level 2 Version 4, describing the structures of the language and the rules used to build a valid model. SBML XML Schema and other related documents and software are also available from the SBML project web site, "http://sbml.org/":http://sbml.org/.
Evolution of protein phosphatases in plants and animals
Authors: Moorhead Greg B. G. , De Wever Veerle , Templeton George , Kerk David
Published: December 2008

Protein phosphorylation appears to be a universal mechanism of protein regulation. Genomics has provided the means to compile inventories of protein phosphatases across a wide selection of organisms and this has supplied insights into the evolution of this group of enzymes. Protein phosphatases evolved independently several times yielding the groups we observe today. Starting from a core catalytic domain, phosphatases evolved by a series of gene duplication events and by adopting the use of regulatory subunits and/or fusion with novel functional modules or domains. Recent analyses also suggest that the serine/threonine specific enzymes are more ancient than the PTPs (protein tyrosine phosphatases). It is likely that the latter played a key role at the onset of metazoan evolution in conjunction with the tremendous expansion of tyrosine kinases and PTPs at this point. In the present review, we discuss the evolution of the PTPs, the serine/threonine specific PPP (phosphoprotein phosphatase) and PPM (metallo-dependent protein phosphatase) families and the more recently discovered phosphatases that utilize an aspartate-based catalytic mechanism. We will also highlight examples of convergent evolution and several phosphatases which are unique to plants.
Observation of spontaneous Raman scattering in silicon slow-light photonic crystal waveguides
Authors: McMillan J. F. , Yu Mingbin , Kwong Dim-Lee , Wong C. W.
Published: December 2008

We report on the observation of spontaneous Raman scattering in silicon photonic crystal waveguides. Continuous-wave measurements of both forward scattered and backscattered Stokes emissions are reported in single line-defect waveguides in hexagonal lattice photonic crystal silicon membranes. By utilizing the Bragg gap edge dispersion of the TM-like mode for pump enhancement and the TE-like fundamental mode onset for Stokes enhancement, the spontaneous Raman scattering coefficient was observed to increase by up to six times in the region of slow group velocity. The results show explicit nonlinear enhancement in a silicon photonic crystal slow-light waveguide device.
High-performance organic integrated circuits based on solution processable polymer-small molecule blends
Authors: Smith Jeremy , Hamilton Richard , Heeney Martin , de Leeuw Dago M. , Cantatore Eugenio , Anthony John E. , McCulloch Iain , Bradley Donal D. C. , Anthopoulos Thomas D.
Published: December 2008

The prospect of realizing high-performance organic circuits via large-area fabrication is attractive for many applications of organic microelectronics. Here we report solution processed organic field-effect transistors and circuits based on polymer-small molecule blends comprising of polytriarylamine and 5,11-bis(triethylsilylethynyl) anthradithiophene. By optimizing blend composition and deposition conditions we are able to demonstrate short channel, bottom-gate, bottom-contact transistors with high mobility and excellent reproducibility. Using these transistors we have built unipolar voltage inverters and ring oscillators with a single stage delay of 712 ns. These are among the fastest organic circuits reported to date and could satisfy the performance requirements of low-end electronic applications.
Modal structure, directional and wavelength jumps of integrated semiconductor ring lasers: Experiment and theory
Authors: Fürst S. , Pérez-Serrano A. , Scirè A. , Sorel M. , Balle S.
Published: December 2008

We have experimentally and theoretically analyzed the modal properties of semiconductor ring lasers and the wavelength jumps that occur in connection with directional switching above the threshold.
Atmospheric glow discharges from the high-frequency to very high-frequency bands
Authors: Walsh J. L. , Iza F. , Kong M. G.
Published: December 2008

This letter reports an experimental investigation of an atmospheric glow discharge in both the high-frequency (HF) band of 3–30 MHz and the very high frequency band of 30–300 MHz. At constant input power, increased frequency is found to change little the electron density and to reduce slightly the electron excitation temperature. Significantly, an eightfold frequency increase from 20 to 80 MHz leads to a 20-fold increase in the maximum plasma power without plasma constriction. The maximum power density of 355 W/cm3 achieved at 80 MHz is far greater than those reported in the HF band.
High temperature electrical resistance of substrate-supported single walled carbon nanotubes
Authors: Avedisian C. Thomas , Cavicchi Richard E. , McEuen Paul M. , Zhou Xinjian , Hurst Wilbur S. , Hodges Joseph T.
Published: December 2008

We report the electrical characteristics of substrate-supported metallic single walled carbon nanotubes at temperatures up to 573 K over a range of bias voltages (Vb) for zero gate voltage in air under atmospheric pressure. Our results show a monotonic increase in resistance with temperature, with an I-Vb characteristic that is linear at high temperature but nonlinear at low temperature. A theory for electrical resistance is applied to the data which shows that the transition to Ohmic behavior at high temperature is the result of optical phonon absorption rather than acoustic phonon scattering.
A method for removing surfactants from an air/water interface
Authors: Kou J. , Saylor J. R.
Published: December 2008

The study of heat, mass, and momentum transport across an air/water interface is an aspect of fluid mechanics where the presence of surfactant monolayers can play a significant role. Experimental studies of air/water transport typically require a method for cleaning the air/water interface so that it is free from any contaminating surfactant monolayer. This may be for the sake of running an experiment under clean surface conditions, or to clean the surface prior to deposition of a known surfactant. Herein a method is described for maintaining a clean air/water interface during conditions of finite air flow over the water surface. The unique aspect of this method is its ability to maintain clean surfaces while experiments are conducted.
High precision high voltage divider and its application to electron beam ion traps
Authors: Chen W. D. , Xiao J. , Shen Y. , Fu Y. Q. , Meng F. C. , Chen C. Y. , Zou Y. , Hutton R.
Published: December 2008

A high precision high voltage divider has been developed for the electron beam ion trap in Shanghai. The uncertainty caused by the temperature coefficient of resistance (TCR) and the voltage coefficient of resistance has been studied in detail and was minimized to the level of ppm (10−6) range. Once the TCR was matched between the resistors, the precision of the dividing ratio finally reached the ppm range also. We measured the delay of the divider caused by the capacitor introduced to minimize voltage ripple to be 2.35 ms. Finally we applied the divider to an experiment to measure resonant energies for some dielectronic recombination processes for highly charged xenon ions. The final energies include corrections for both space charge and fringe field effects are mostly under 0.03%.
Rapid preparation method of bulk nanostructured Yb0.3Co4Sb12+y compounds and their improved thermoelectric performance
Authors: Li Han , Tang Xinfeng , Zhang Qingjie , Uher Ctirad
Published: December 2008

A synthetic route was introduced to speed up the preparation of high performance nanostructured Yb0.3Co4Sb12+y (y=0.3 and 0.6) compounds. Compared with the samples prepared by a traditional method, the processing time is reduced from the typical 10 days to less than 40 h, the Yb filling fraction limit increases, and the resulting thermoelectric transport properties are improved significantly. As a consequence, the dimensionless figure of merit of our bulk nanostructured Yb0.3Co4Sb12.3 reaches 1.3 at 800 K. The enhanced thermoelectric performance coupled with the dramatically reduced processing time will be of considerable significance to the commercial-scale production of skutterudite-based thermoelectric materials.
onHigh-peak-power strain-compensated GaInAs/AlInAs quantum cascade lasers (λ∼4.6 μm) based on a slightly diagonal active region design
Authors: Yang Q. , Lösch R. , Bronner W. , Hugger S. , Fuchs F. , Aidam R. , Wagner J.
Published: December 2008

Employing a “slightly diagonal” active region design for the quantum cascade lasers compared to a reference sample based on the conventional vertical transition design [R. Köhler et al., Appl. Phys. Lett. 76, 1092 (2000)], we have improved the maximum operation temperature, room-temperature maximum peak power per facet, and room-temperature slope efficiency from 320 K, 200 mW, and 570 mW/A to higher than 360 K, 3.2 W, and 2200 mW/A, respectively, for the device size of 16 μm×3 mm with as-cleaved facets operated in pulsed mode.
A new tensile stage for in situ electron microscopy examination of the mechanical properties of “superelastic” specimens
Authors: Dragnevski Kalin I. , Fairhead Trevor W. , Balsod Rik , Donald Athene M.
Published: December 2008

We have developed a novel tensile stage that can be used for in situ electron microscopy examination of the mechanical properties of “superelastic” materials. In our stage, one of the specimen clamps is replaced by a cylindrical roller, which when driven by a motor can easily stretch (“roll on”) any specimen irrespective of its plastic properties. We have used the so-called Roll-o-meter in the study of the tensile behavior of two different film formed latex formulations, here referred to as standard and novel. We find that the values of the tensile strength and extension to break of the studied systems, measured by using the Roll-o-meter, are similar to those measured by a Hounsfield tensile testing machine outside the microscope chamber. Further, in situ environmental scanning electron microscopy examination of the deformation and failure of the lattices revealed that the standard specimens exhibit a more ductile behavior, compared to the novel ones.
Viscoelastic mechanical behavior of soft microcantilever-based force sensors
Authors: Lin I-Kuan , Liao Yen-Ming , Liu Yan , Ou Kuang-Shun , Chen Kuo-Shen , Zhang Xin
Published: December 2008

Polydimethylsiloxane (PDMS) microcantilevers have been used as force sensors for studying cellular mechanics by converting their displacements to cellular mechanical forces. However, PDMS is an inherently viscoelastic material and its elastic modulus changes with loading rates and elapsed time. Therefore, the traditional approach to calculating cellular mechanical forces based on elastic mechanics can result in errors. This letter reports a more in-depth method for viscoelastic characterization, modeling, and analysis associated with the bending behavior of the PDMS microcantilevers. A viscoelastic force conversion model was developed and validated by proof-of-principle bending tests.
Epitaxial growth of GaN films grown on single crystal Fe substrates
Authors: Okamoto K. , Inoue S. , Matsuki N. , Kim T.-W. , Ohta J. , Oshima M. , Fujioka H. , Ishii A.
Published: December 2008

GaN films have been grown on single crystalline Fe(110), Fe(100), and Fe(111) substrates with low-temperature AlN buffer layers by the use of pulsed laser deposition. AlN films with 30° rotated domains and polycrystalline AlN films grow on Fe(100) and Fe(111), respectively. On the other hand, AlN(0001) films grow epitaxially on Fe(110) substrates. X-ray reflectivity measurements have revealed that the heterointerface of AlN∕Fe(110) is quite abrupt and that its abruptness remains unchanged, even after annealing at 700°C. GaN epitaxial films have been grown on AlN∕Fe(110) structures with an in-plane relationship of GaN[11−20]∥AlN[11−20]∥Fe[001]. The first-principles calculations have revealed that this in-plane epitaxial relationship is determined by the adsorption process of nitrogen atoms on the Fe surfaces at the initial stage of the growth.
Glyconanoparticles allow pre-symptomatic in vivo imaging of brain disease
Authors: van Kasteren Sander I. , Campbell Sandra J. , Serres Sébastien , Anthony Daniel C. , Sibson Nicola R. , Davis Benjamin G.
Published: December 2008

Initial recruitment of leukocytes in inflammation associated with diseases such as multiple sclerosis (MS), ischemic stroke, and HIV-related dementia, takes place across intact, but activated brain endothelium. It is therefore undetectable to symptom-based diagnoses and cannot be observed by conventional imaging techniques, which rely on increased permeability of the blood–brain barrier (BBB) in later stages of disease. Specific visualization of the early-activated cerebral endothelium would provide a powerful tool for the presymptomatic diagnosis of brain disease and evaluation of new therapies. Here, we present the design, construction and in vivo application of carbohydrate-functionalized nanoparticles that allow direct detection of endothelial markers E-/P-selectin (CD62E/CD62P) in acute inflammation. These first examples of MRI-visible glyconanoparticles display multiple copies of the natural complex glycan ligand of selectins. Their resulting sensitivity and binding selectivity has allowed acute detection of disease in mammals with beneficial implications for treatment of an expanding patient population suffering from neurological disease.
Use of the Rad51 promoter for targeted anti-cancer therapy
Authors: Hine Christopher M. , Seluanov Andrei , Gorbunova Vera
Published: December 2008

Rad51 protein, involved in homologous recombination, is overexpressed in a variety of tumors, and its expression is correlated with a poor prognosis. Here we propose to exploit the overexpression of Rad51 in cancer cells to design a
Rad51
promoter-based anticancer therapy. On average, Rad51 mRNA and protein levels are increased in cancer cells four- and sixfold, respectively. Serendipitously, we discovered that when the
Rad51
ORF is replaced with another ORF, the difference in promoter activity between normal and cancer cells increases to an average of 840-fold with a maximum difference of 12,500-fold. This dramatic difference in activity has high therapeutic potential. We demonstrate that the fusion of
Rad51
promoter to diphtheria toxin A (DTA) gene kills a variety of cancer cell types, including breast cancer, fibrosarcoma, and cervical cancer cells, with minimal effect on normal breast epithelial cells and normal fibroblasts. Our results suggest that therapies based on the
Rad51
promoter will be highly tumor specific and open new avenues for targeting a broad range of cancers.
Population genetics of
Trypanosoma brucei gambiense
, the agent of sleeping sickness in Western Africa
Authors: Koffi Mathurin , De Meeûs Thierry , Bucheton Bruno , Solano Philippe , Camara Mamadou , Kaba Dramane , Cuny Gérard , Ayala Francisco J. , Jamonneau Vincent
Published: December 2008

Human African trypanosomiasis, or sleeping sickness caused by
Trypanosoma brucei gambiense
, occurs in Western and Central Africa.
T. brucei
s.l. displays a huge diversity of adaptations and host specificities, and questions about its reproductive mode, dispersal abilities, and effective size remain under debate. We have investigated genetic variation at 8 microsatellite loci of
T. b. gambiense
strains isolated from human African trypanosomiasis patients in the Ivory Coast and Guinea, with the aim of knowing how genetic information was partitioned within and between individuals in both temporal and spatial scales. The results indicate that (
i
) migration of
T. b. gambiense
group 1 strains does not occur at the scale of West Africa, and that even at a finer scale (e.g., within Guinea) migration is restricted; (
ii
) effective population sizes of trypanosomes, as reflected by infected hosts, are probably higher than what the epidemiological surveys suggest; and (
iii
)
T. b. gambiense
group 1 is most likely a strictly clonally reproducing organism.