bluuebunny/crossref_metadata_2025 huggingface dataset:
Preliminary evidence that synanthropic flies contribute to the transmission of trachoma- causing Chlamydia trachomatis in Latin America
Authors: Reilly Lucy A. , Favacho Joana , Garcez Lourdes M. , Courtenay Orin
Published: June 2007

Synanthropic flies have been shown to be important mechanical vectors of Chlamydia trachomatis, which causes trachoma. However entomological studies have not been forthcoming in Latin America. This study assesses the relationship between household dipteran fly densities and active childhood trachoma in a village on Marajó Island, Pará state, Brazil. For 78 households, members were examined for signs of trachoma, relative abundance of potential trachoma vectors (Diptera, Chloropidae and Diptera, Muscidae) was quantified by trap counts, and additional measures of household hygiene associated with C. trachomatis transmission were assessed. Active childhood trachoma prevalence was 24.1% (45/187), present in 46.2% of sampled households with evidence of case clustering. Childhood prevalence was positively associated with increased fly densities, whereas indirect measures of sanitary conditions (latrine ownership and perceived importance of flies) showed a protective effect. This study indicates that C. trachomatis can be transmitted by synanthropic flies in this region of Latin America.
Prevalência de osteoporose: uma revisão crítica
Authors: Frazão Paulo , Naveira Miguel
Published: June 2007

A queda da mortalidade, seguida da redução da fecundidade e aumento da expectativa de vida, resulta no envelhecimento da população e no aumento das taxas de doenças crônico-degenerativas, entre as quais a osteoporose. Pesquisas epidemiológicas vêm sendo desenvolvidas com a finalidade de estimar sua prevalência na população empregando diferentes técnicas. O propósito dessa investigação foi revisar os estudos de prevalência de osteoporose e discutir suas implicações do ponto de vista da Saúde Coletiva. Foi realizada revisão da literatura mediante a qual foram incluídas publicações contendo estimativas de prevalência da osteoporose calculadas a partir da densidade mineral óssea aferida pela absorção de raios X de dupla energia. Os dados foram classificados segundo o ano, a região ou o país, autor, características da população investigada, e sítio esquelético. Os resultados mostraram ampla dispersão entre as taxas, com os valores variando entre 0,4% e 40,0% de acordo com o sítio pesquisado, o grupo etário, o sexo e o tipo de estudo. Nos estudos de base populacional, os valores das estimativas por ponto variaram de 7,9% a 16,0% considerando DMO no sítio femoral de mulheres com 50 e mais anos de idade. Nas áreas brasileiras mais desenvolvidas é necessário implementar projetos para conhecer sua prevalência incluindo-a na agenda dos formuladores de políticas públicas.
Determinantes do ganho ponderal excessivo durante a gestação em serviço público de pré-natal de baixo risco
Authors: Stulbach Tamara E. , Benício Maria Helena D'Aquino , Andreazza Rosemarie , Kono Silvia
Published: June 2007

INTRODUÇÃO: O excesso de ganho de peso durante a gestação pode ocasionar retenção de peso pós-parto e contribuir para a obesidade no sexo feminino. METODOLOGIA: Neste estudo, avaliou-se a influência de fatores sociodemográficos, história gestacional, tabagismo, trabalho fora de casa e estado nutricional inicial sobre o ganho ponderal excessivo (GPE). O GPE foi estimado a partir das. recomendações do IOM (ganho semanal >0,58g, >0,53g e >0,39g, correspondentes a estado de nutricional no início da gestação: desnutrida, adequada e sobrepeso/obesidade, respectivamente). Estudou-se uma coorte de 141 gestantes saudáveis, inscritas em serviço público de pré-natal, entre março de 1997 e março de 1998. A influência dos fatores de estudo sobre o GPE foi testada separadamente no 2º e 3º trimestres mediante análise de regressão de Poisson múltipla hierarquizada. RESULTADOS: Dentre as 237 elegíveis houve 37,8% de perdas, não se detectando diferenças estatisticamente significativas para as variáveis centrais do estudo. A incidência de GPE no 2º trimestre foi de 38,6% (IC95% 30,5 - 47,2) e no 3º trimestre foi de 36,4% (IC95% 28,5 - 45,0). No 2º trimestre, apenas a escolaridade mostrou-se associada ao GPE. Em relação às mulheres com menos de 5 anos de escolaridade, as gestantes com 5 a 8 anos e acima de 8 anos de escolaridade apresentaram riscos relativos correspondentes a 2,09 (IC95% 1,03 - 4,25) e 2,62 (IC95% 1,32 - 5,22), respectivamente. No 3º trimestre mostraram significância estatística as variáveis: escolaridade >8 anos (RR=1,91 [IC95% 1,22 - 2,97], ausência de companheiro (RR=1,66 [(IC95% 1,06 - 2,59], primiparidade (RR=2,13 [IC95% 1,20 - 3,85] e estado nutricional inicial adequado e sobrepeso/obesidade (RR=1,53 [IC95% 0,82 _ 2,84] e RR=2,02 [IC95% 1,04 - 3,92], respectivamente) em relação às desnutridas. CONCLUSÃO: Em função da elevada freqüência de GPE, particularmente em mulheres de escolaridade mais alta, as sem companheiro, as primíparas e aquelas com estado nutricional inicial adequado ou sobrepeso/obesidade durante a gestação, mais atenção deveria ser dada à prevenção e ao controle do problema durante o pré-natal.
Writing Rape, Trauma, and Transnationality onto the Female Body
Authors: Schultermandl Silvia
Published: June 2007

In Nora Okja Keller's Comfort Woman (1997), the Korean American protagonist reconciles with her Korean heritage through the act of spreading her mother's ashes. This essay looks at Keller's use of a “language of the body” that protests against rape and other forms of oppression of the female body. This language of the body does not rely on essentialist parameters of “race” or of women's “nature.” On the contrary, by depicting rape as universal, non-culture–specific issue, Keller's novel sketches a mother–daughter relationship where the daughter finds a way to identify with the mother despite the fact that the mother remains, at times, the cultural “Other.” It is a shared experience of rape and trauma that facilitates a means of understanding between mother and daughter and serves as a point of contact for the building of transnational feminist solidarity between women of different cultures.
Adaptive backstepping control for a class of time delay systems with nonlinear perturbations
Authors: Hua Chang‐Chun , Wang Qing‐Guo , Guan Xin‐Ping
Published: June 2007

The sliding mode control method has been extensively employed to stabilize time delay systems with nonlinear perturbations. Although the resulting closed‐loop systems have good transient and steady‐state performances, the designed controllers are dependent on the time delays. But one knows that it is difficult to obtain the precise delay time in practical systems, especially when it is time varying. In this paper, we revisit the problem and use the backstepping method to construct the state feedback controller. First, a coordinate transformation is used to obtain a cascade time delay system. Then, a linear virtual control law is designed for the first subsystem. The memoryless controller is further constructed based on adaptive method for the second subsystem with the uncertainties bounded by linear function. By choosing new Lyapunov–Krasovskii functional, we show that the system state converges to zero asymptotically. Via the proposed approach, we also discuss the case that the uncertainties are bounded by nonlinear functions. Finally, simulations are done to verify the effectiveness of the main results obtained. Copyright © 2007 John Wiley & Sons, Ltd.
A kriging method for the solution of nonlinear programs with black‐box functions
Authors: Davis Eddie , Ierapetritou Marianthi
Published: June 2007

In this article, a new methodology is developed for the optimization of black‐box systems lacking a closed‐form mathematical description. To properly balance the computational cost of building the model against the probability of convergence to global optimum, a hybrid methodology is proposed. A kriging approach is first applied to provide information about the global behavior of the system considered, whereas a response surface method is considered close to the optimum to refine the set of candidate local optima and find the global optimum. The kriging predictor is a global model employing normally distributed basis functions, so both an expected sampling value and its variance are obtained for each test point. The presented work extends the capabilities of existing response surface techniques to address the refinement of optima located in regions described by convex asymmetrical feasible regions containing arbitrary linear and nonlinear constraints. The performance of the proposed algorithm is compared to previously developed stand‐alone response surface techniques and its effectiveness is evaluated in terms of the number of function calls required, number of times the global optimum is found, and computational time. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Highly Luminescent, Neutral, Nine‐Coordinate Lanthanide(III) Complexes
Authors: Kottas Gregg S. , Mehlstäubl Marita , Fröhlich Roland , De Cola Luisa
Published: June 2007

Using a simple ligand design, we have prepared neutral, nine‐coordinate lanthanide complexes that exclude water from the inner coordination sphere, thus leading to high emission quantum yields and long excited‐state lifetimes. The complexes form in high synthetic yields (49–87 %) by simply mixing the ligand and the lanthanide. Visible luminescence from EuIII (Φ = 60 %, τ = 2.2 ms) and TbIII (Φ = 7 %, τ = 0.2 ms) and near‐infrared luminescence from YbIII (Φ = 0.7 %), NdIII and ErIII were observed in acetonitrile and CH2Cl2 at room temperature. In addition, the GdIII complex was prepared to gain information about the triplet state of the ligand. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Peptidomimetics, Glycomimetics and Scaffolds from Carbohydrate Building Blocks
Authors: Murphy Paul V.
Published: June 2007

Saccharides, due to their high density of functional groups and availability as chiral building blocks are scaffolds for bioactive compound discovery. Pyranosides and iminosugar‐based peptidomimetics have been synthesised as ligands for somatostatin receptors and HIV protease. The synthesis of polyhydroxylated macrolides related to natural products and cyclophanes has been achieved from carbohydrate fragments with a view to investigation of their potential as scaffolds. In addition, the trajectory of aromatic systems grafted to saccharides have been studied and this has led to the synthesis of probes for the study of carbohydrate protein interactions. These compounds include geometrically diverse bivalent glycomimetics derived from scaffolds that are hybrids of sugars and aromatic groups. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
QM/MM study of catalytic methyl transfer by the N5‐glutamine SAM‐dependent methyltransferase and its inhibition by the nitrogen analogue of coenzyme
Authors: Wu Ruibo , Cao Zexing
Published: June 2007

The combined density functional quantum mechanical/molecular mechanical (QM/MM) approach has been used to investigate methyl‐transfer reactions catalyzed by the N5‐glutamine S‐adenosyl‐L‐methionine (SAM)‐dependent methyltransferase (HemK) and the coenzyme‐modified HemK with the replacement of SAM by a nitrogen analogue. Calculations reveal that the catalytic methyl transfer by HemK is an energy‐favored process with an activation barrier of 15.7 kcal/mol and an exothermicity of 12.0 kcal/mol, while the coenzyme‐modified HemK is unable to catalyze the methyl transfer because of a substantial barrier of 20.6 kcal/mol and instability of the product intermediate. The results lend support to the experimental proposal that the nitrogen analogue of the SAM coenzyme should be a practicable inhibitor for the catalytic methyl transfer by HemK. Comparative QM/MM calculations show that the protein environment, especially the residues Asn197 and Pro198 in the active site, plays a pivotal role in stabilizing the transition state and regulating the positioning of reactive groups. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Selective asymmetry in a conserved forebrain to midbrain projection
Authors: Kuan Yung‐Shu , Gamse Joshua T. , Schreiber Alexander M. , Halpern Marnie E.
Published: June 2007

How the left and right sides of the brain acquire anatomical and functional specializations is not well understood. The zebrafish has proven to be a useful model to explore the genetic basis of neuroanatomical asymmetry in the developing forebrain. The dorsal diencephalon or epithalamus consists of the asymmetric pineal complex and adjacent paired nuclei, the left and right medial habenulae, which in zebrafish larvae, exhibit differences in their size, neuropil density and patterns of gene expression. In all vertebrates, axons from the medial habenular nuclei project within a prominent fiber bundle, the fasciculus retroflexus, to a shared midbrain target, the interpeduncular nucleus of the ventral tegmentum. However, in zebrafish, projections from the left habenula innervate the dorsal and ventral regions of the target nucleus, whereas right habenular efferents project only to the ventral region. A similar dorsoventral difference in habenular connectivity is found in another teleost species, the highly derived southern flounder, Paralichthys lethostima. In this flatfish, directional asymmetry of the habenular projection appears to be independent of the left–right morphology and orientation that an individual adopts post‐metamorphosis. Comparative anterograde labeling of the brains of salamanders, frogs and mice reveals that axons emanating from the left and right medial habenulae do not project to different domains, but rather, they traverse the target nucleus in a complementary mirror image pattern. Thus, although the habenulo‐interpeduncular conduction system is highly conserved in the vertebrate brain, the stereotypic dorsoventral topography of left–right connections appears to be a feature that is specific to teleosts. J. Exp. Zool. (Mol. Dev. Evol.) 308B:669–678, 2007. © 2007 Wiley‐Liss, Inc.
Tools and techniques for transferring know‐how from boomers to gamers
Authors: Kapp Karl M.
Published: June 2007

How well boomers transfer their knowledge to younger employees (gamers∥ may well determine which organizations maintain their competitive edge during the next decade. But boomers' and gamers' preferred learning styles are as different as night and day, and conventional approaches may hinder rather than aid knowledge transfer. Fortunately, companies can learn a lot from gamers about sharing knowledge. Instant messaging, blogs, wikis, RSS feeds, and podcasts—technologies gamers already use extensively outside the work environment to obtain information—are efficient, low‐cost tools for informal learning that companies can incorporate into an enterprise strategy for capturing and distributing business‐ and job‐critical know‐how before it's too late. © 2007 Karl M. Kapp.
Calculation of vibration transmission over bedrock using a waveguide finite element model
Authors: Peplow A. T. , Finnveden S.
Published: June 2007

A finite element method is developed for the study of elastic wave propagation in layered ground environments. The formulation is based on a spectral finite‐element approach using a mixture of high‐order element shape functions and wave solutions. The numerical method provides solutions to vibration transmission on and within layered elastic waveguides. Examples of its use include the theoretical analysis of transmission of vibrations in the vicinity of the surface of the ground. The mathematical model is two dimensional, and the interior of the ground is modelled as an elastic layer overlying a rigid foundation. An analysis of the natural modes of free vibration in a single layer and two layers is presented and compared with known results. In addition the forced response of the layers, for which the surface is assumed to be subjected to a harmonic point force load is shown. These results also include an illustration of the attenuation of surface vibration due to ‘wave impedance blocks’ in the ‘near field’ of the source up to a frequency of 200 Hz for two soil types. Copyright © 2007 John Wiley & Sons, Ltd.
Untruthful probabilistic demand forecasts in vendor‐managed revenue‐sharing contracts: Coordinating the chain
Authors: Gerchak Yigal , Khmelnitsky Eugene , Robinson Lawrence W.
Published: June 2007

Vendor‐managed revenue‐sharing arrangements are common in the newspaper and other industries. Under such arrangements, the supplier decides on the level of inventory while the retailer effectively operates under consignment, sharing the sales revenue with his supplier. We consider the case where the supplier is unable to predict demand, and must base her decisions on the retailer‐supplied probabilistic forecast for demand. We show that the retailer's best choice of a distribution to report to his supplier will not be the true demand distribution, but instead will be a degenerate distribution that surprisingly induces the supplier to provide the system‐optimal inventory quantity. (To maintain credibility, the retailer's reports of daily sales must then be consistent with his supplied forecast.) This result is robust under nonlinear production costs and nonlinear revenue‐sharing. However, if the retailer does not know the supplier's production cost, the forecast “improves” and could even be truthful. That, however, causes the supplier's order quantity to be suboptimal for the overall system. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007
Numerical verification of solutions for Signorini problems using Newton‐like method
Authors: Ryoo Cheon Seoung
Published: June 2007

We proposed a numerical method to verify the existence of solutions for a simplified Signorini problem (Comput. Math. Appl. 2000; 40:1003–1013). Using sequential iteration method, we numerically constructed a set containing solutions that satisfies the hypothesis of Schauder's fixed point theorem in a certain Sobolev space. It is difficult to apply this method to the problem of which associated operator is not retractive in a neighborhood of the solution. In this paper, in order to overcome such a difficulty, we describe an alternative approach to this problem. Numerical examples are presented. Copyright © 2007 John Wiley & Sons, Ltd.
Slug control in Australian canola: monitoring, molluscicidal baits and economic thresholds
Authors: Nash Michael A , Thomson Linda J , Hoffmann Ary A
Published: June 2007

Exotic slugs have become serious pests of canola, at establishment, in Southern Australian high‐rainfall cropping zones. Slugs were monitored using relatively inexpensive 300 mm × 300 mm terracotta tiles acting as refuges. An investigation was made of the effects of the time of application of chelated iron baits on the slug species Deroceras reticulatum Müller and Lehmannia nyctelia Bourguignat. Baits reduced the number of surface‐active slug species. A single application at sowing provided greater efficacy than one application before sowing, and efficacy was comparable with that of two applications. Canola seedling densities showed a negative response to D. reticulatum numbers; the presence of even one individual per refuge trap reduced seedling numbers below optimum densities. Thistles and other vegetation were associated with increased numbers of slugs. European guidelines for slug monitoring and damage appear to be at least partly applicable to Australian conditions. Copyright © 2007 Society of Chemical Industry
Patterns of fish diversity in a mainstem Missouri River reservoir and associated delta in South Dakota and Nebraska, USA
Authors: Kaemingk Mark A. , Graeb Brian D. S. , Hoagstrom Christopher W. , Willis David W.
Published: June 2007

There is an expansive and expanding delta at the confluence of the Niobrara and Missouri Rivers in the Lewis and Clark Reservoir. The delta provides diverse aquatic habitat that is somewhat similar to the historic Missouri River and to remnant river habitats. As such, the delta may have relatively high fish species diversity compared to lentic reservoir habitats. To compare patterns of fish diversity between the delta and reservoir habitats, we collected fish in several nursery habitats in both areas using four gear types (seine, gill net, electrofisher and fyke net) on three occasions (July, August and September) in 2005. Species richness was higher in the delta (n = 34) than the reservoir (n = 22). Thirteen species composed more than 1% of delta collections while only four species composed more than 1% of reservoir collections. Species diversity (Fisher's α) was also significantly higher in the delta. Higher species diversity in the delta may be explained by higher habitat diversity. These results suggest that newly forming deltas have the potential to protect and restore fish species diversity, because they retain natural river functions such as sediment transport and habitat formation. Copyright © 2007 John Wiley & Sons, Ltd.
Synthese und Festkörperstruktur des Koordinationspolymers {Zn[Sn(CH2SMe)4]0.5Cl2}n
Authors: Ruth Kai , Müller Manuela , Bolte Michael , Bats Jan W. , Wagner Matthias , Lerner Hans‐Wolfram
Published: June 2007

Synthesis and Solid State Structure of the Coordination Polymer {Zn[Sn(CH2SMe)4]0.5Cl2}n

The tin compounds Sn(CH2SMe)4 and Sn(CH2PPh2)4 are accessible from reaction of SnCl4 with LiCH2SMe and LiCH2PPh2, respectively. X‐ray quality crystals of Sn(CH2PPh2)4 (tetragonal, ) are obtained from a benzene solution at 4 °C. The lithium methanide [Li(PMDTA)CH2PPh2], which was a starting material in the synthesis of Sn(CH2PPh2)4 crystallized from a mixture of diethyl ether and pentane at −20 °C in the monoclinic space group P21/c. The coordination polymer {Zn[Sn(CH2SMe)4]0.5Cl2}n was synthesized from Sn(CH2SMe)4 and ZnCl2 in benzene. The solid state structure of this coordination polymer reveals that {Zn[Sn(CH2SMe)4]0.5Cl2}n possesses an infinite [Zn‐SMe‐CH2‐Sn‐CH2‐SMe‐]‐chain as its backbone (monoclinic P21/c).
Thermodynamic and Kinetic Characterization of Duplex Formation between 2′-O, 4′-C-Methylene-modified Oligoribonucleotides, DNA and RNA
Authors: Christensen Ulla
Published: June 2007

2′-O,4′-C-methylene-linked ribonucleotide derivatives, named LNA (locked nucleic acid) and BNA (bridged nucleic acid) are nucleic acid analogoues that have shown high-affinity recognition of DNA and RNA, and the employment of LNA oligomers for antisense activity, gene regulation and nucleic acid diagnostics seems promising. Here we show kinetic and thermodynamic results on the interaction of a series of 10 bases long LNA–DNA mixmers, gabmers as well as full length LNA's with the complementary DNA, RNA and LNA oligonucleotides in the presence and absence of 10 mM Mg2+- ions. Our results show no significant differences in the reaction thermodynamics and kinetics between the LNA species, only a tendency to stronger duplex formation with the gabmer and mixmer. Introduction of a few LNA's thus may be a better strategy, than using full length LNA's to obtain an oligonucleotide that markedly increases the strength of duplexes formed with the complementary DNA and RNA.
Nicaea and Its Legacy: An Introduction
Authors: Ayres Lewis
Published: June 2007

It is a privilege to have the opportunity for such extended reflection on my book Nicaea and Its Legacy. No doubt some authors feel that their manuscripts are truly finished before they are published: I am one of those who merely abandons a manuscript to the copy editors when other pressures demand an end to hostilities. It should be no surprise, then, that I have always envisaged Nicaea as a snapshot of a moving landscape, not just in the ever-growing body of scholarship on the fourth century, but also in my own thinking. Accordingly I will begin here as I was invited to do in our discussion at Harvard, by offering an account of what I think Nicaea accomplishes and of some areas in which the book needs further work.
Intra-operative imaging in paediatric cardiac surgery: the reactions of parents who requested and watched a video of the surgery performed on their child
Authors: Kocyildirim Ergin , Franck Linda S. , Elliott Martin J.
Published: June 2007

Objective

Our previous work demonstrated that digital video recording of operations is the best way to describe the morphological features and complex dynamic physiology of surgical treatment of congenitally malformed hearts. Parental consent is required for video recording, and some parents have requested, and obtained, a copy of the video of the operation performed on their child. Our present aim was to explore their feelings and opinions having viewed the recording of the surgical procedures.

Design and participants

This exploratory study examined the views of 17 parents, comprising 7 couples, 2 mothers, and 1 father, after requesting, and then watching, the recording of the operation performed on their child. The audio-taped, semistructured interviews were analyzed for the thematic content.

Results

All parents watched the videos at least once, and no parent exhibited distress as a result. Curiosity and desire for learning, and wanting to know what exactly happened to the child during the operation, were the most common reasons for requesting the video. Parents reported that the videos were also useful in sharing the experience with family and friends. The videos had no effect on the attitudes of the parents towards the surgical team. Parents made recommendations to increase the length of the edited videos and add labels and voice-overs.

Conclusion

Parents of children with congenitally malformed hearts want to watch the recording of the operation performed because of their need for information, and to understand the experience of their children when separated from them. Research is needed to assess the potential value of operative videos in facilitating parental knowledge and coping when children undergo major cardiac surgery.
The40Ar/39Ar chronology and eruption rates of Cenozoic volcanism in the eastern Bering Sea Volcanic Province, Alaska
Authors: Mukasa Samuel B. , Andronikov Alexander V. , Hall Chris M.
Published: June 2007

The eastern sector of the Bering Sea Volcanic Province, Alaska, consists of a number of large late Cenozoic volcanic fields that occur in a broad region inboard from the Aleutian arc front to the Arctic Circle. We estimate that about 750 km3of magma were erupted in the volcanic centers that we have studied, all within the past 6.0 Ma. Several discrete eruption episodes have been identified with the new40Ar/39Ar data at circa 6.0 Ma (Imuruk volcanic field), circa 3.5 Ma (Teller volcanic field), circa 2.5–1.5 Ma (St. George Island), circa 1.0 Ma (St. Lawrence Island), and the youngest activity which started at circa 0.7 Ma and continued throughout region until historic times. Combining age information with volume estimates reveals that the intensity of volcanic activity in the Bering Sea Volcanic Province has increased through time, with only about 15% of lava erupted before 3 Ma and about 30% of all late Cenozoic magma erupted within the last 500 ka. Eruption rates also increase toward more recent times, from the 6 Ma Imuruk basalts, which erupted at the rate of ∼70 ± 15 m3km−2yr−1, to the ≤0.7 Ma Nunivak Island and St. Michael volcanic field basalts, which erupted at a rate of ∼165 ± 25 m3km−2yr−1. High volumes of erupted lava accompanied by high eruption rates for the youngest volcanic rocks suggest significant changes in the melting rates, which are best explained by either an evolving tectonic regime or significant changes in the melting processes.
A composite solution method for physical equations and its application in the Nea Kessani geothermal field (Greece)
Authors: Yu Hwa‐Lung , Christakos George , Modis Konstantinos , Papantonopoulos George
Published: June 2007

We propose a method for solving physical equations under conditions of uncertainty and we use it to study the Nea Kessani (Greece) geophysical system formed by a thermal reservoir of arcosic sandstones. The method is based on the Bayesian maximum entropy theory and generates temperature solutions that are (1) composite, in the sense that apart from being consistent with the physical model, they also account for the multisourced uncertainty of the model parameters and the site‐specific information at a set of vertical drill holes indicating that hot fluids rising from depth enter the reservoir in a restricted area and flow toward local thermal springs; and (2) complete, in the sense that the whole temperature probability density is generated at each spatial location. From these densities, different temperature maps can be derived (most probable, error minimizing, etc., maps), depending on the study objectives. The proposed composite solution is distinguished from the standard (direct) physical model solution in a formal mathematical sense. By means of comparative analysis, it is shown that the numerical composite solution is more informative than the direct temperature solution as well as the analytical solution obtained using simplified boundary conditions (the composite solution offers a more realistic representation of the real‐world phenomenon, and unlike the previous methods, it is in agreement with empirical quartz geothermometry analyses). The composite method can be a valuable contribution for scientists and engineers working on incorporating secondary information for improving the quality of the solutions obtained from a physical model in general.
Effects of changes in CO2, climate, and land use on the carbon balance of the land biosphere during the 21st century
Authors: Müller Christoph , Eickhout Bas , Zaehle Sönke , Bondeau Alberte , Cramer Wolfgang , Lucht Wolfgang
Published: June 2007

We studied the effects of climate and land‐use change on the global terrestrial carbon cycle for the 21st century. Using the process‐based land biosphere model (LPJmL), we mechanistically simulated carbon dynamics for natural and managed lands (agriculture and forestry) and for land‐use change processes. We ran LPJmL with twelve different dynamic land‐use patterns and corresponding climate and atmospheric CO2 projections. These input data were supplied from the IMAGE 2.2 implementations of the IPCC‐SRES storylines for the A2, B1, and B2 scenarios. Each of these SRES scenarios was implemented under four different assumptions on spatial climate patterns in IMAGE 2.2, resulting in twelve different Earth System projections. Our selection of SRES scenarios comprises deforestation and afforestation scenarios, bounding a broad range of possible land‐use change. Projected land‐use change under different socio‐economic scenarios has profound effects on the terrestrial carbon balance: While climate change and CO2 fertilization cause an additional terrestrial carbon uptake of 105–225 PgC, land‐use change causes terrestrial carbon losses of up to 445 PgC by 2100, dominating the terrestrial carbon balance under the A2 and B2 scenarios. Our results imply that the potential positive feedback of the terrestrial biosphere on anthropogenic climate change will be strongly affected by land‐use change. Spatiotemporally explicit projections of land‐use change and the effects of land management on terrestrial carbon dynamics need additional attention in future research.
LTD‐Thellier paleointensity of 1.2 Ga Nova Floresta mafic rocks (Amazon craton)
Authors: Celino Klaydson R. , Trindade Ricardo I. F. , Tohver Eric
Published: June 2007

Absolute paleointensity at 1.2 Ga was obtained on basalts and gabbros from Nova Floresta Formation (Amazon craton, Brazil). Magnetic carriers in these rocks are single‐domain to multi‐domain pure (to nearly pure) magnetite. They present a strong decrease in remanence after low‐temperature demagnetization (LTD) accompanied by an increase in median destructive fields. Incorporation of LTD to Thellier double‐heating measurements improved paleointensity estimates and enabled paleofield recovery for otherwise sterile rock samples, giving twenty seven successful determinations for six sites (45% success rate). Site‐mean paleofield values are within 4.90μT and 15.55μT (mean at 8.37 ± 4.07μT). These results correspond to a mean VDM of 2.08 ± 0.94 × 1022Am2, thus increasing the number of low‐field determinations that dominate the (still scarce) Precambrian database. Our study exemplifies the need for alternative approaches in the study of ancient rocks.
IP3 receptor antagonist, 2‐APB, attenuates cisplatin induced Ca2+‐influx in HeLa‐S3 cells and prevents activation of calpain and induction of apoptosis
Authors: Splettstoesser F , Florea A‐M , Büsselberg D
Published: June 2007

Background and purpose:

Cisplatin drives specific types of tumour cells to apoptosis. In this study we investigate the involvement of intracellular calcium ([Ca2+]i) in triggering apoptosis in two different cell lines. As cisplatin is used for the treatment of several forms of cancer we choose HeLa‐S3 and U2‐OS as two examples of tumour cell lines.

Experimental approach:

Cisplatin (1nM–10μM) was applied to HeLa‐S3 and U2‐OS cells and [Ca2+]i measured with fluo‐4, using laser scanning microscopy. Inositol‐1,4,5‐trisphosphate (IP3) receptors were visualized with immunostaining. Membrane conductances were measured with patch‐clamp techniques. Levels of calpain and caspases were assessed by western blots and apoptotic cells were stained with Hoechst 33342 and counted.

Key results:

Cisplatin increases [Ca2+]i concentration‐dependently in HeLa‐S3 but not in U2‐OS cells. This elevation of [Ca2+]i depended on extracellular Ca2+ but was reduced by the IP3 receptor blocker, 2‐APB. This effect was not due to a Ca2+ release triggered by Ca2+ entry. Immunostaining showed IP3‐receptors (type1‐3) at the cellular membrane of HeLa‐S3 cells, but not in U2‐OS cells. Electrophysiological experiments showed an increased membrane conductance with cisplatin only when Ca2+ was present extracellularly. Increase of [Ca2+]i was related to the activation of calpain but not caspase‐8 and triggered apoptosis in HeLa‐S3 but not in U2‐OS cells.

Conclusions and implications:

Our observations on the activation of IP3‐receptors, calcium entry and apoptotic rate by cisplatin in specific carcinogenic cells might open new possibilities in the treatment of some forms of cancer.

British Journal of Pharmacology (2007) 151, 1176–1186; doi:10.1038/sj.bjp.0707335
Interaction of ligands for the peroxisome proliferator‐activated receptor γ with the endocannabinoid system
Authors: Lenman A , Fowler C J
Published: June 2007

Background and purpose:

There is good evidence that agents interacting with the endocannabinoid system in the body can also interact with the peroxisome proliferator‐activated receptorγ. The present study was designed to test whether the reverse is true, namely whether peroxisome proliferator‐activated receptorγligands have direct effects upon the activity of the endocannabinoid metabolizing enzyme fatty acid amide hydrolase.

Experimental approach:

Fatty acid amide hydrolase activity was measured in rat brain homogenates, C6 glioma and RBL2H3 basophilic leukaemia cells. Cellular uptake of anandamide was also assessed in these cells.

Key results:

Peroxisome proliferator‐activated receptorγactivators inhibited the metabolism of the endocannabinoid anandamide in rat brain homogenates with an order of potency MCC‐555 > indomethacin ≈ ciglitazone ≈ 15‐deoxy‐Δ12,14‐prostaglandin J2≈ pioglitazone > rosiglitazone > troglitazone. The antagonists BADGE, GW9662 and T0070907 were poor inhibitors of anandamide hydrolysis. The inhibition by ciglitazone was competitive and increased as the pH of the assay buffer was decreased; the Kivalue at pH 6.0 was 17μM. In intact C6 glioma cells assayed at pH 6.2, significant inhibition of anandamide hydrolysis was seen at 3μM ciglitazone, whereas 100μM was required to produce significant inhibition at pH 7.4. Ciglitazone also interacted with monoacylglycerol lipase as well as with cannabinoid CB1and CB2receptors.

Conclusions and implications:

Ciglitazone may be useful as a template for the design of novel dual action anti‐inflammatory agents which are both inhibitors of fatty acid amide hydrolase and agonists at the peroxisome proliferator‐activated receptorγ.

British Journal of Pharmacology(2007)151, 1343–1351; doi:10.1038/sj.bjp.0707352
Thermodynamic analysis of ligands at cholecystokinin CCK2receptors in rat cerebral cortex
Authors: Harper E A , Roberts S P , Kalindjian S B
Published: June 2007

Background and purpose:

Several studies using radioligand binding assays, have shown that measurement of thermodynamic parameters can allow discrimination of agonists and antagonists (Weilandet al., 1979;Boreaet al., 1996a). Here we investigate whether agonists and antagonists can be thermodynamically discriminated at CCK2receptors in rat cerebral cortex.

Experimental approach:

The pKLof [3H]‐JB93182 in rat cerebral cortex membranes was determined at 4, 12, 21 and 37°C in 50 mMTris‐HCl buffer (buffer B pH 6.96; containing 0.089 mMbacitracin). pKIvalues of ligands of diverse chemical structure and with differing intrinsic activity (α), as defined by the lumen‐perfused rat and mouse stomach bioassays, were determined in buffer B at 4, 12, 21 and 37°C.

Key results:

[3H]‐JB93182 labelled a homogeneous population of receptors in rat cerebral cortex at 4, 12, 21 and 37°C and the pKLand Bmaxwere not altered by incubation temperature. [3H]‐JB93182 binding reached equilibrium after 10, 50, 90 and 220 min at 37, 21, 12 and 4°C, respectively. pKIvalues forR‐L‐365,260,R‐L‐740,093, YM220, PD134,308 and JB95008 were higher at 4°C than at 37°C. There was no effect of temperature on pKIvalues for pentagastrin, CCK‐8S,S‐L‐365,260, YM022, PD140,376 and JB93242.

Conclusions and implications:

CCK2receptor agonists and antagonists at rat CCK2receptors cannot be discriminated by thermodynamic analysis using [3H]‐JB93182 as the radioligand.

British Journal of Pharmacology(2007)151, 1352–1367; doi:10.1038/sj.bjp.0707355
Hot electron and x-ray production from intense laser irradiation of wavelength-scale polystyrene spheres
Authors: Sumeruk H. A. , Kneip S. , Symes D. R. , Churina I. V. , Belolipetski A. V. , Dyer G. , Landry J. , Bansal G. , Bernstein A. , Donnelly T. D. , Karmakar A. , Pukhov A. , Ditmire T.
Published: June 2007

Hot electron and x-ray production from solid targets coated with polystyrene-spheres which are irradiated with high-contrast, 100fs, 400nm light pulses at intensity up to 2×1017W∕cm2 have been studied. The peak hard x-ray signal from uncoated fused silica targets is an order of magnitude smaller than the signal from targets coated with submicron sized spheres. The temperature of the x-rays in the case of sphere-coated targets is twice as hot as that of uncoated glass. A sphere-size scan of the x-ray yield and observation of a peak in both the x-ray production and temperature at a sphere diameter of 0.26μm, indicate that these results are consistent with Mie enhancements of the laser field at the sphere surface and multipass stochastic heating of the hot electrons in the oscillating laser field. These results also match well with particle-in-cell simulations of the interaction.
Direct measurement of cantilever spring constants and correction for cantilever irregularities using an instrumented indenter
Authors: Ying Z. Charles , Reitsma Mark G. , Gates Richard S.
Published: June 2007

A method is presented that allows direct measurement of a wide range of spring constants of cantilevers using an indentation instrument with an integrated optical microscope. An uncertainty of less than 10% can be achieved for spring constants from 0.1to102N∕m. The technique makes it possible to measure the spring constant at any desired location on a cantilever of any shape, particularly at the tip location of an atomic force microscopy cantilever. The article also demonstrates a technique to detect and correct apparent length anomalies of cantilevers by analyzing spring constants at multiple positions.
Low temperature physical properties of a Ni-Mo-Cr alloy Haynes® 242™
Authors: Lu J. , Han K. , Choi E. S. , Jo Y. , Balicas L. , Xin Y.
Published: June 2007

Haynes 242 is a Ni-Mo-Cr based superalloy. High strength and high fracture toughness at low temperatures make Haynes 242 an attractive choice for cryogenic applications such as the conduit material for the cable-in-conduit conductor of superconducting magnets. In this work, its low temperature physical properties including magnetization, specific heat, electrical resistivity, thermal conductivity, and Seebeck coefficient are measured from 2to300K. Haynes 242 shows Curie paramagnetism with a Curie constant C=0.0289K. The electrical resistivity has a minimum at ∼12K and shows weakly linear T dependence at high temperatures as expected. The specific heat Cp between 10 and 40K can be fitted by Cp=γT+AT3 with γ=9.43×10−5J∕gK2 and A=5.91×10−7J∕gK4. Below 10K, an upturn in Cp∕T with decreasing T is interpreted by the existence of very small ferromagnetic clusters which is supported by our magnetization data. The thermal conductivity is analyzed by separating the electronic and phonon contributions. The relatively strong phonon thermal conduction at temperatures <100K results in effective Lorenz number a few times larger than the ideal Lorenz number. Our results suggest that Haynes 242 is suitable for many cryogenic applications including conduit for large superconducting magnet and low temperature probe.
Microphotoreflectance spectroscopy of heterojunction bipolar transistors under biasing voltage: Measurement of the net doping concentration
Authors: Chouaib Houssam , Bru-Chevallier Catherine
Published: June 2007

The authors present a microphotoreflectance (micro-PR) spectroscopic study of a biased InGaAlAs∕GaAsSb∕InP heterojunction bipolar transistor. Franz Keldysh oscillations from an InGaAlAs emitter are studied as a function of the static biasing voltage applied to the emitter-base junction. The electric field value from the InGaAlAs emitter is decreasing under direct biasing voltage. The change in electric field value is shown to be in good agreement within the expected operation of forward biased junction, and making possible a straight measurement of the net doping concentration. Results show the feasibility of a micro-PR spectroscopy analysis of devices under operation.
Effect of microstructure on hydrogen permeation through thermally stable, sputtered palladium-silver alloy membranes
Authors: McLeod L. S. , Degertekin F. L. , Fedorov A. G.
Published: June 2007

The authors report on fabrication and hydrogen separation performance of an array of thin, freestanding Pd∕Ag alloy membranes. Film deposition from an alloyed sputtering target results in robust film characteristics. Long-term stability of the membranes has been demonstrated with experimental testing at temperatures of 473–627K. Within the testing period the membrane has withstood more than 30 thermal cycles by returning to ambient temperature between subsequent tests. Throughout the long-term testing, hydrogen permeation levels have increased by more than a factor of 2. Electron microscopy of the membranes indicates that performance enhancement is due to microstructural changes which are promoted at elevated temperatures.
Phase transitional behavior in K0.5Na0.5NbO3–LiTaO3 ceramics
Authors: Dai Yejing , Zhang Xiaowen , Zhou Guoyuan
Published: June 2007

In addition to x-ray diffraction, Raman spectrum measurements provide direct evidence of the tetragonal and orthorhombic phases coexistence in lead-free ceramics (1−x)K0.5Na0.5NbO3 (KNN)–xLiTaO3 when x equals 5mol%. This is caused by the phase transition temperature between tetragonal and orthorhombic decreasing to around room temperature due to the Li and Ta doping in KNN, and not by constituting a region of morphotropic phase boundary as presented by most published papers. The results indicate that although this kind of ceramic displays good properties, it needs further study to verify if it is suitable to be used in a varying temperature environment.
The Structure of Pupils' Worries During Transition from Junior to Secondary School
Authors: Brown Jennifer M. , Armstrong R.
Published: June 2007

Transfer from junior to secondary school is not necessarily accomplished painlessly by children. There has been a general failure to monitor the child's own perception of transition. Worries, as experienced by pupils themselves, may be uncovered by collecting accounts from children (N = 173). Problems in analysing qualitative date are overcome by using a non‐metric multidimensional scaling analysis (the Guttman‐Lingoes Smallest Space Analysis). This procedure intercorrelates items (worries) and represents them as points in a spatial array. Three distinct regions are identifiable in the multidimensional space concerning worries about interpersonal and social relationships, school work and discipline. The structure of these three sources of worries is demonstrated by means of another Guttman procedure, partial order scalogram analysis (POSA). Worries are shown to be qualitatively and quantitatively different over time. Teachers' perception of worries are demonstrated to be different from those of the children. Findings are discussed in relation to pastoral care.
Educational Priority Indices: a new perspective
Authors: Sammons Pamela , Kysel Florisse , Mortimore Peter
Published: June 2007

Criticisms of the concept of educational priority indices and reasons for the continued use of a school‐based policy are outlined with reference to the educational priority indices employed by the ILEA over the last decade. During 1981 a major review of the methods and measures used to construct the ILEA indices was undertaken. Details of criticisms of the data and methodology used in the past are provided. A new method of constructing the indices to take into account the relationships between different measures and educational outcome at the individual level was devised. The results of analyses of these relationships and an outline of the new method of constructing indices are presented. Advantages of adopting a ‘risk index’ method of weighting the educational priority measures to take into account the cumulative effects of social factors are discussed.
The Lexical Bar: lexical change from 12 to 15 years measured by social class, region and ethnicity
Authors: Corson David
Published: June 2007

Three measuring instruments are used in this study of 12‐ and 15‐year‐old children's passive vocabulary, active vocabulary and lexical diversity. Children are drawn from samples delimited by two social class backgrounds and by West Indian (Jamaican) background. Research was performed in north London and South Yorkshire. Highly significant differences are found in lexical access, by age, to semantic fields representative of knowledge categories of the school curriculum and highly significant differences by ethnic background at 15 years. In lexical diversity, with controls applied as in this study, there is no significant difference between sample means. In active use of specialist words of Graeco‐Latin origin there are highly significant differences between the social classes and the social groups at 15 years, the age when final assessments of potential in education are being made. Because Graeco‐Latin words populate the knowledge categories of the school curriculum almost to the exclusion of Anglo‐Saxon words, the writer proposes that a ‘lexical bar’ is at work for some social dialect users in societies which use English as the principal language of communication. This bar has the effect of hindering the users of some social dialects from a ready access to the lexis of semantic categories essential for success in education.