bluuebunny/crossref_metadata_2025 huggingface dataset:
Acid‐catalysed hydrolysis of methoxy‐substituted trityl trifluoroethyl ethers: a kinetic and computational investigation of leaving group effects
Authors: López Moisés Canle , Demirtas Ibrahim , Maskill Howard , Mishima Masaaki
Published: May 2008

Trityl trifluoroethyl (TFE) ether and its 4‐methoxy, 4,4′‐dimethoxy‐, and 4,4′,4″‐trimethoxy‐substituted analogues have been prepared; the dimethoxy and trimethoxy compounds undergo ready acid‐catalysed hydrolysis at constant ionic strength = 1 mol dm−3 at 25°C. The monomethoxy compound is less reactive and the parent trityl analogue showed minimal reactivity. Using presently reported and literature kinetics results with pKa values of protonated substrates, first‐order rate constants covering 12 orders of magnitude have been determined for heterolysis/dissociation of 11 protonated dimethoxytrityl derivatives DMTrYH+ where YH = H2O, CF3CH2OH, ArNH2 and RNH2. There is a good correlation between logarithms of these rate constants and the pKa values of the conjugate acids (Y) of the nucleofuges YH. Enthalpies and corresponding free energies at 25°C for the dissociation of the specifically solvated ions CH3 (YH = MeOH and CF3CH2OH, n = 1; H2O, n = 2; and NH3, n = 3) have been calculated at the B3LYP/6‐31+G* level. Corresponding gas phase calculations have also been carried out for Ph3C (YH = H2O, n = 2; MeOH, n = 1; CF3CH2OH, n = 1 and NH3, n = 3) and, in addition, structures for these solvated ions with (YH = H2O, MeOH and NH3) have been calculated. The specifically solvated ion Ph3CO(H)CH2CF3(H2O)+ does not correspond to a stable bonded species in the gas phase, which suggests that acid‐catalysed fragmentation of methoxy‐substituted analogues of Ph3COCH2CF3 in aqueous solution are concerted with proton transfer in which case the hydrolytic cleavage will be general acid catalysed. Copyright © 2008 John Wiley & Sons, Ltd.
Oesophageal cancer: caregiver mental health and strain
Authors: Donnelly M. , Anderson L.A. , Johnston B.T. , Watson R.G.P. , Murphy S.J. , Comber H. , McGuigan J. , Reynolds J.V. , Murray L.J.
Published: May 2008

Objective: To investigate strain and mental health among family caregivers of oesophageal cancer patients and possible factors associated with caregiver mental health and strain.

Methods: Patients with oesophageal adenocarcinoma in Ireland were recruited into the FINBAR study (the main aim of which was to investigate factors influencing the Barrett's adenocarcinoma relationship). Carers completed the 13‐item Caregiver Strain Index and the General Health Questionnaire‐30 (GHQ) in the context of a brief interview with trained research staff that was undertaken separately from the interview with each cancer patient.

Results: Two hundred and twenty‐seven patients participated in the FINBAR study. A total of 39 patients did not have a family carer or the carer could not be identified. Fifty percent (94/188) of carers completed the questionnaires. Mean (SD) scores for strain (6.65, SD=3.63) and mental health status (10.21, SD=7.30) were high and 71% of carers scored >5 on the GHQ indicating psychological distress. There was a statistically significant positive relationship between level of strain experienced by caregivers and the severity of their mental health status and whether or not carers scored >5 on the GHQ. Relatives were 1.70 (95% CI 1.34–2.15) times more likely to be defined as high scorers with each unit increase in the CSI score.

Conclusions: A significant proportion of caregivers experienced high levels of strain and psychological distress. There is a need to provide appropriate support and services targeted specifically at reducing the considerable strain of caring for patients with oesophageal cancer, particularly for carers of patients from lower socioeconomic groups. Copyright © 2008 John Wiley & Sons, Ltd.
The structure of the anti‐c‐myc antibody 9E10 Fab fragment/epitope peptide complex reveals a novel binding mode dominated by the heavy chain hypervariable loops
Authors: Krauß Norbert , Wessner Helga , Welfle Karin , Welfle Heinz , Scholz Christa , Seifert Martina , Zubow Kristina , Aÿ Jacqueline , Hahn Michael , Scheerer Patrick , Skerra Arne , Höhne Wolfgang
Published: May 2008

The X‐ray structure of the Fab fragment from the anti‐c‐myc antibody 9E10 was determined both as complex with its epitope peptide and for the free Fab. In the complex, two Fab molecules adopt an unusual head to head orientation with the epitope peptide arranged between them. In contrast, the free Fab forms a dimer with different orientation. In the Fab/peptide complex the peptide is bound to one of the two Fabs at the “back” of its extended CDR H3, in a cleft with CDR H1, thus forming a short, three‐stranded antiparallel β‐sheet. The N‐ and C‐terminal parts of the peptide are also in contact with the neighboring Fab fragment. Comparison between the CDR H3s of the two Fab molecules in complex with the peptide and those from the free Fab reveals high flexibility of this loop. This structural feature is in line with thermodynamic data from isothermic titration calorimetry. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Evidence for cross‐adaptation between s‐triazine herbicides resulting in reduced efficacy under field conditions
Authors: Krutz L Jason , Burke Ian C , Reddy Krishna N , Zablotowicz Robert M
Published: May 2008

BACKGROUND: Enhanced atrazine degradation has been observed in agricultural soils from around the globe. Soils exhibiting enhanced atrazine degradation may be cross‐adapted with other s‐triazine herbicides, thereby reducing their control of sensitive weed species. The aims of this study were (1) to determine the field persistence of simazine in atrazine‐adapted and non‐adapted soils, (2) to compare mineralization of ring‐labeled 14C‐simazine and 14C‐atrazine between atrazine‐adapted and non‐adapted soils and (3) to evaluate prickly sida control with simazine in atrazine‐adapted and non‐adapted soils.

RESULTS: Pooled over two pre‐emergent (PRE) application dates, simazine field persistence was 1.4‐fold lower in atrazine‐adapted than in non‐adapted soils. For both simazine and atrazine, the mineralization lag phase was 4.3‐fold shorter and the mineralization rate constant was 3.5‐fold higher in atrazine‐adapted than in non‐adapted soils. Collectively, the persistence and mineralization data confirm cross‐adaptation between these s‐triazine herbicides. In non‐adapted soils, simazine PRE at the 15 March and 17 April planting dates reduced prickly sida density at least 5.4‐fold compared with the no simazine PRE treatment. Conversely, in atrazine‐adapted soils, prickly sida densities were not statistically different between simazine PRE and no simazine PRE at either planting date, thereby indicating reduced simazine efficacy in atrazine‐adapted soils.

CONCLUSIONS: Results demonstrate the potential for cross‐adaptation among s‐triazine herbicides and the subsequent reduction in the control of otherwise sensitive weed species. Copyright © 2008 Society of Chemical Industry
Insomnia: guide to diagnosis and choice of treatment
Authors: Wilson Sue , Nutt David
Published: May 2008

The tiredness and poor performance associated with insomnia have a considerable impact on quality of life. Our Drug Review considers when drug treatments are justified and which are preferred, followed by sources of further information and a review of prescription data. Copyright © 2008 Wiley Interface Ltd
Colesevelam: new alternative or adjunctive treatment to statins
Authors: Chaplin Steve , Durrington Paul
Published: May 2008

Colesevelam (Cholestagel) is a new bile acid sequestrant for treating hypercholesterolaemia either alone or in combination with a statin. Here, Steve Chaplin describes the clinical trial data relating to its efficacy and safety, and Professor Durrington comments on its place in reducing raised cholesterol levels. Copyright © 2008 Wiley Interface Ltd
Assessment and treatment options for erectile dysfunction
Authors: Cummings Michael
Published: May 2008

Erectile dysfunction is a common disorder that can also be associated with underlying diabetes or cardiovascular disease. Here, the author describes the assessment of ED and currently available treatment options. Copyright © 2008 Wiley Interface Ltd
Determination of underivatized amino acid δ13C by liquid chromatography/isotope ratio mass spectrometry for nutritional studies: the effect of dietary non‐essential amino acid profile on the isotopic signature of individual amino acids in fish
Authors: McCullagh James , Gaye‐Siessegger Julia , Focken Ulfert
Published: May 2008

This study provides data for the effect of dietary non‐essential amino acid composition on the δ13C values of individual amino acids in rainbow trout (Oncorhynchus mykiss) using liquid chromatography coupled to isotope ratio mass spectrometry (LC/IRMS). In this experiment, trout were reared either on a control diet or on three experimental diets, differing in the composition of non‐essential/conditionally essential amino acids, for a period of 6 weeks. The control diet was a commercial trout starter feed with fish meal as the main protein source. The experimental diets contained no protein, only synthetic amino acids. Diet 1 resembled the composition of fish meal in both essential and non‐essential amino acids, Diet 2 had all essential amino acids, but cysteine, glycine, proline and tyrosine were replaced by the corresponding amounts of their precursors, and in Diet 3 all non‐essential amino acids were replaced by glutamate. LC/IRMS was used for the determination of δ13C values of individual amino acids from diets and tissues without derivatization. Diet affected the δ13C of individual amino acids in fish. For fish on Diets 1–3 amino acid δ13C values showed a similar trend: phenylalanine showed very little change from diet to body tissue. Arginine, lysine, tyrosine and proline showed strong depletion from diet to body tissue and glycine, alanine, aspartate and serine all showed variable but strong enrichment in 13C. Improvements are necessary before all amino acid δ13C values can be determined; however, this study demonstrates that measuring amino acid isotopic signatures by LC/IRMS is a promising new technique for nutritional physiologists. Copyright © 2008 John Wiley & Sons, Ltd.
The evolution of the mixing rate of a simple random walk on the giant component of a random graph
Authors: Fountoulakis N. , Reed B.A.
Published: May 2008

In this article we present a study of the mixing time of a random walk on the largest component of a supercritical random graph, also known as the giant component. We identify local obstructions that slow down the random walk, when the average degree d is at most O($ \sqrt{\ln n} $), proving that the mixing time in this case is Θ((n/d)2) asymptotically almost surely. As the average degree grows these become negligible and it is the diameter of the largest component that takes over, yielding mixing time Θ(n/d) a.a.s.. We proved these results during the 2003–04 academic year. Similar results but for constant d were later proved independently by Benjamini et al. in 3. © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2008
Modelling and control of variable‐speed multi‐pole permanent magnet synchronous generator wind turbine
Authors: Hansen Anca D. , Michalke Gabriele
Published: May 2008

Emphasis of this article is on variable‐speed pitch‐controlled wind turbines with multi‐pole permanent magnet synchronous generator (PMSG) and on their extremely soft drive‐train shafts. A model and a control strategy for a full back‐to‐back converter wind turbine with multi‐pole PMSG are described. The model comprises submodels of the aerodynamic rotor, the drive‐train by a two‐mass model, the permanent magnet generator and the full‐scale converter system. The control strategy, which embraces both the wind turbine control itself and the control of the full‐scale converter, has tasks to control independently the active and reactive powers, to assist the power system and to ensure a stable normal operation of the wind turbine itself. A multi‐pole PMSG connected to the grid through a full‐scale converter has no inherent damping, and therefore, such configuration can become practically unstable, if no damping by means of external measures is applied. In this work, the frequency converter is designed to damp actively the drive‐train oscillations, thus ensuring stable operation. The dynamic performance of the presented model and control strategy is assessed and emphasized in normal operation conditions by means of simulations in the power system simulation tool DIgSILENT. Copyright © 2008 John Wiley & Sons, Ltd.
Wind turbine load level based on extrapolation and simplified methods
Authors: Freudenreich Kai , Argyriadis Kimon
Published: May 2008

This paper describes some effects on the load level of state‐of‐the‐art multi‐megawatt wind turbines introduced by the new edition of the standard IEC 61400‐1:2005 ‘Wind Turbines—Part 1: Design Requirements’. Compared to the previous edition, the extreme load determination has been modified by applying stochastic and statistical analyses. Within this paper, the effect on the extreme load level of wind turbines based on the newly introduced load extrapolation and extreme turbulence model (ETM) is demonstrated and occurring problems are discussed. Load simulations have been carried out for four state‐of‐the‐art multi‐megawatt wind turbines of different design concepts and from different manufacturers. The blade root bending moments and tip deflection have been determined by applying different extrapolation methods. Advantages and disadvantages of these methods and tail fittings are discussed and interpreted. The obtained loads are partly compared with long‐term simulations. The application of the ETM is demonstrated. The dependence of the load level on the turbulence intensity and control system, as well as the interaction with extrapolated loads, is discussed and limitations are outlined. The obtained load level is compared to the overall load level of the turbines according to the previous edition of the standard, IEC 61400‐1:1999. Based on extrapolated loads, simplified methods are described to obtain loads without load extrapolation to reduce the effort for simulation and post‐processing. Copyright © 2008 John Wiley & Sons, Ltd.
Intrinsic and extrinsic rewards in a nonformal environmental education program
Authors: Price Emily A. , Vining Joanne , Saunders Carol D.
Published: May 2008

Humans are surrounded by threats to the environment, many of their own making. The severity of environmental problems will not decrease unless action is taken to develop and encourage greater environmentally responsible behavior (ERB) in the general populace. Environmental education (EE) is one method for strengthening precursors to ERB such as knowledge and attitudes, but research on the connection is currently unclear. In this paper we present the results of a study investigating the role played by rewards in encouraging ERB precursors for adults and children involved in a zoo‐based Nature Swap program. We used semistructured interviews to question 91 participants, including 38 children, 38 adult guardians, and 15 staff members regarding the importance of rewards in the program. We content analyzed the interviews to identify and describe major themes and then coded them. We found that adult guardians and Play Partners perceived intrinsic and extrinsic rewards as aiding in maintaining motivation and interest in the nonformal Nature Swap program. In addition, both children and adult companion participants in the program mentioned strengthened precursors to ERB. Overall we found that adult companions perceived that children who participated in the program spent more quality time outdoors and had a heightened awareness of their surroundings as a result of program‐based rewards. Implications for other EE and conservation education programs are discussed. Zoo Biol 28:361–376, 2009. © 2008 Wiley‐Liss, Inc.
Study of color stability of tall oil fatty acids through isolation and characterization of minor constituents
Authors: Min David B. S. , Lin Sherman S. , Chang Stephen S.
Published: May 2008

Minor constituents in high quality tall oil fatty acids have been isolated successfully by liquid column chromatography, using silicic acid as the adsorbent. The minor constituents contained two types of compounds: those which were noneffective and those which were effective in causing the darkening of tall oil fatty acids during heating. The former consisted oftrans‐3,5‐dimethoxystilbene and rosin acids. The latter was separated into numerous fractions by the combination of chemical methods, silicic acid column chromatography, and low temperature fractional crystallization. The fractions were characterized by functional group analyses, chemical reactions, and UV and IR spectrometric methods. Most of the fractions contained two‐three times as much oxygen in the molecule as the original sample and were highly oxidized fatty acids. They had mol wt ranging 300–551 and contained double bonds, carbonyl, ester, peroxide, and hydroxyl groups. The effect of these minor constituents upon the color stability of tall oil fatty acids during heating was postulated as being due to the hydroxyl groups located in the α‐position to the double bond in the molecule.
Toxicology and biochemistry of butylated hydroxyanisole and butylated hydroxytoluene
Authors: Branen A. L.
Published: May 2008

Butylated hydroxyanisole and butylated hydroxytoluene are used extensively as food antioxidants. It is estimated that man consumes ca. 0.1 mg/kg body wt daily of these antioxidants. At levels 500 times this level (50 mg/kg/day), both butylated hydroxyanisole and butylated hydroxytoluene appear to be free of any obviously injurious effects. However, at larger doses (500 mg/kg/day), both butylated hydroxyanisole and butylated hydroxytoluene result in certain pathological, enzyme, and lipid alterations in both rodents and monkeys, and butylated hydroxytoluene, in some cases, has been reported to have certain teratogenic and carcinogenic effects upon rodents. These alterations appear to differ markedly between rodents and monkeys, apparently as a result of differences which exist in the metabolism and excretion of butylated hydroxyanisole and butylated hydroxytoluene by these two species. However, in both animal species, the alterations appear to be physiological responses which are reversible upon removal of butylated hydroxyanisole and butylated hydroxytoluene from the diet. Long term chronic ingestion of butylated hydroxyanisole and butylated hydroxytoluene may be beneficial in sparing vitamin E and in modifying the acute toxicity of a number of mutagenic and carcinogenic chemicals.
Absent Flexor Pollicis Longus: Case Report with Review of Literature
Authors: Suresh S. S. , Abraham Raju , Kumar S. Santhosh
Published: May 2008

An asymptomatic absence of flexor pollicis longus without association with any other anomaly or hypoplasia of the thenar muscles in a 28-year-old patient is reported due to its rarity. The inability to flex the interphalangeal joint of the thumb and the absent flexor crease of the thumb led us to identify the absent tendon, and the tendon could not be palpated in the flexor crease of the thumb. Routine X-rays, ultrasound scans, and a computed tomography with soft tissue enhancement was used to confirm and document the condition. The patient was not referred for a magnetic resonance imaging, facilities for which are not available in the center where the author is working, as he was not keen in surgical interference.
Effect of a biological response modifier on cellular death mechanisms at drying off
Authors: Dallard Bibliana E , Baravalle Celina , Ortega Hugo , Ruffino Valeria , Heffel Silvia , Calvinho Luis F
Published: May 2008

Agents that increase natural protective mechanisms have been proposed for prevention and treatment of intramammary infections. The objective of this study was to describe the effects of a single intramammary infusion of a lipopolysaccharide (LPS)-based biological response modifier (BRM) on cellular death mechanism in uninfected andStaphylococcus aureus-infected bovine mammary glands during involution. Three groups of 12 cows, each one including 6Staph. aureus-infected and 6 uninfected, were infused in two mammary quarters with BRM or placebo and slaughtered at 7, 14 and 21 d of involution. In infected quarters, BRM treatment produced a significant increase in percent of stained epithelial cells for the apoptosis-promoting protein Bax at every observation period. In addition, BRM produced a significant increase of immunostained stromal cells for Bax compared with placebo-treated quarters. BRM treatment produced an increase in percentages of epithelial cells staining with active caspase-3 at 7 d and 14 d of involution compared with placebo-treated quarters and a significant decrease in percentages of terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL)-positive epithelial cells at 7 d and 21 d of involution. In addition, BRM treatment caused an increase in percentage of stromal cells immunostaining for active caspase-3 and TUNEL. An increase of active caspase-3 and TUNEL epithelial and stromal cell immunostaining was observed inStaph. aureus-infected compared with uninfected quarters. Cellular proliferation, determined by Ki-67 immunostaining, was increased in epithelial and stromal cells fromStaph. aureus-infected compared with uninfected quarters at every observation period. These results provide new insights into the mechanism of mammary cell death in uninfected andStaph. aureus-infected bovine mammary gland during involution and illustrate the effects of LPS-based BRM on apoptosis and cell proliferation during mammary involution.
Calcium-enriched goats' milk aids recovery of iron status better than calcium-enriched cows' milk, in rats with nutritional ferropenic anaemia
Authors: Nestares Teresa , Barrionuevo Mercedes , Díaz-Castro Javier , López-Aliaga Inmaculada , Alférez Ma José M , Campos Margarita S
Published: May 2008

Ca-Fe interactions are known, but no studies are available about the effects of Ca-enriched goat or cow milk on Fe status in nutritional ferropenic anaemia (NFA). To examine this matter, control and Fe-deficient rats were fed for 14 d with goat or cow milk diets containing either normal or high Ca content (5000 or 10 000 mg/kg diet), and different indices and parameters related to iron status were measured. The apparent digestibility coefficient (ADC) and the Fe retention/intake (R/I) ratio were higher in control and anaemic rats fed goat milk diet (G diet), despite high-Ca content. Ca enrichment decreased Fe stores in liver and sternum in anaemic rats fed cow milk diet (C diet), however G diet did not modify Fe content in the organs studied in control and anaemic rats. In anaemic rats, Ca-supplementation decreased haematocrit, but platelets and serum Fe were not affected, however, in control rats platelets increased except for Ca-enriched G diet, this fact reveals that Ca-Fe interaction is minimized with G diet. Serum ferritin was always higher in rats fed Gvs. C diet, both in control and anaemic rats fed either normal or Ca-enriched diets. Ca-supplementation decreased ferritin levels in control and anaemic rats fed C diet and also, though to a lesser extent, in those given the G diet. This indicates that with this G diet there is a better recovery of body Fe stores in anaemic rats, despite Ca-supplementation. In this study it is noteworthy that despite high Ca content, a goat milk diet resulted in minimal Ca-Fe interactions and did not adversely affect Fe status in rats with NFA.
Effects of supplemental dietary fatty acids on milk yield and fatty acid composition in high and medium yielding cows
Authors: Weisbjerg Martin Riis , Wiking Lars , Kristensen Niels Bastian , Lund Peter
Published: May 2008

The present study tested the hypothesis that supplemental dietary fatty acids (FA) affect the energy corrected milk yield in proportion to the milk production level of dairy cows, and increase both long chain FA proportion of milk FA and milk fat globule diameter. Sixteen Danish Holstein cows were divided into four 4×4 Latin squares with two squares of medium yielding cows (32·2 kg energy corrected milk (ECM)/d; 158 days in milk (DIM)) and two squares of high yielding cows (40·0 kg ECM/d; 74 DIM). Experimental length was 12 weeks, with three weeks for each of the four periods. The four treatments were no supplementation (17 g FA/kg dry matter (DM)) and three diets with supplemented FA (29, 40, and 52 g total FA/kg DM, respectively) obtained by substituting barley with Palm Fatty Acid Distillate (PFAD) fat. Diets were offered as total mixed rations with 63% grass/clover silage (DM basis). Dry matter intake decreased with increasing FA supplementation, but net energy intake was not affected. The general linear responses to 10 g/kg DM increase in FA level were 1·1 kg ECM (P<0·0001), 0·061 kg milk fat (P<0·0001), 0·012 kg milk protein (P=0·09) and 0·052 kg lactose (P=0·0002) per day, and linear responses in milk composition were 0·39 g fat (P=0·07), −0·71 g protein (P<0·0001) and 0·05 g lactose (P=0·3) per kg milk, and 0·092 μm (P<0·0001) in milk fat average globule diameter. Fatty acid supplementation decreased short- and medium-chain FA and C16:0 and increased C18:1 proportions of total FA in milk. Supplemental dietary FA increased ECM yield but not in proportion to production level as anticipated, and increased average FA chain length and milk fat globule diameter.
Using dairy herd improvement records and clinical mastitis history to identify subclinical mastitis infections at dry-off
Authors: Torres Audrey H , Rajala-Schultz Päivi J , DeGraves Fred J , Hoblet Kent H
Published: May 2008

Interest in selective dry cow therapy (SDCT) has been increasing owing to concerns over development of antimicrobial resistance. Implementation of SDCT, however, requires a quick and cost-effective on-farm method for identifying cows for treatment and cows that can be left without treatment. The objective of the present study was to evaluate the use of clinical mastitis (CM) history and somatic cell counts (SCC) from monthly Dairy Herd Improvement (DHI) records in identification of infected and uninfected cows at dry-off. A total of 647 Holstein cows were classified as uninfected or infected at dry-off based on CM history and varying number of monthly SCC records (with three different SCC cut-offs). Cows were considered uninfected based on the following criteria: (1) SCC <100 000 cells/ml and no CM during the lactation; (2) SCC <200 000 cells/ml and no CM during the lactation; (3) as criterion two, but additionally a cow was also considered uninfected if it experienced a case of CM during the first 3 months of the lactation and the SCC was <100 000 cells/ml for the rest of the lactation; (4) SCC <300 000 cells/ml and no CM during the lactation; otherwise they were considered infected. Infected and uninfected cows at dry-off were most efficiently identified using three months' SCC records with a threshold of 200 000 cells/ml for cows without CM during the lactation and a threshold of 100 000 cells/ml during the rest of lactation for cows with CM during the first 90 days in milk. Moreover, this criterion also most efficiently identified cows infected with major pathogens only at dry-off. The success of the criteria used for identifying infected and uninfected cows will, however, depend on herd characteristics, such as prevalence of infection and type of pathogens present in the herd.
“The smuggling of La Francophonie”: Francophone Africans in Anglophone Cape Town (South Africa)
Authors: VIGOUROUX CÉCILE B.
Published: May 2008

Focusing on Black Francophone migrants in Cape Town, it is argued that a locally based Francophone identity has emerged in South Africa that questions the institutional discourse of La Francophonie as the organization of French-speaking states. The new identity has little to do with the organization's ideology of a transnational community of people united by a common language and culture. This is shown by deconstructing the category of passeurs de Francophonie (literally ‘smugglers of la Francophonie’ as practice) to which the organization assigns migrants in non-Francophone countries who allegedly spread the French language and Francophone culture. It is argued that the notion of “Francophone” must be grounded empirically and approached in relation to the social environment of the relevant speakers. The post-apartheid South African setting assigns it a meaning different from what it has in Francophone states.
Differential equations and asymptotic solutions for arithmetic Asian options: ‘Black–Scholes formulae’ for Asian rate calls
Authors: DEWYNNE J. N. , SHAW W. T.
Published: May 2008

In this article, we present a simplified means of pricing Asian options using partial differential equations (PDEs). We first provide a concise derivation of the well-known similarity reduction and exact Laplace transform solution. We then analyse the problem afresh as a power series in the volatility-scaled contract duration, with a view to obtaining an asymptotic solution for the low-volatility limit, a limit which presents difficulties in the context of the general Laplace transform solution. The problem is approached anew from the point of view of asymptotic expansions and the results are compared with direct, high precision, inversion of the Laplace transform and with numerical results obtained by V. Linetsky and J. Vecer. Our asymptotic formulae are little more complicated than the standard Black–Scholes formulae and, working to third order in the volatility-scaled expiry, are accurate to at least four significant figures for standard test problems. In the case of zero risk-neutral drift, we have the solution to fifth order and, for practical purposes, the results are effectively exact. We also provide comparisons with the hybrid analytic and finite-difference method of Zhang.
Theory of finite or infinite trees revisited
Authors: DJELLOUL KHALIL , DAO THI-BICH-HANH , FRÜHWIRTH THOM
Published: May 2008

We present in this paper a first-order axiomatization of an extended theoryTof finite or infinite trees, built on a signature containing an infinite set of function symbols and a relationfinite(t), which enables to distinguish between finite and infinite trees. We show thatThas at least one model and prove its completeness by giving not only a decision procedure, but a full first-order constraint solver that gives clear and explicit solutions for any first-order constraint satisfaction problem inT. The solver is given in the form of 16 rewriting rules that transform any first-order constraintinto an equivalent disjunction φ of simple formulas such that φ is either the formulatrueor the formulafalseor a formula having at least one free variable, being equivalent neither totruenor tofalseand where the solutions of the free variables are expressed in a clear and explicit way. The correctness of our rules implies the completeness ofT. We also describe an implementation of our algorithm in CHR (Constraint Handling Rules) and compare the performance with an implementation in C++ and that of a recent decision procedure for decomposable theories.
CoRoT: pioneer space mission for exoplanet transit search
Authors: Barge Pierre , Baglin Annie , Auvergne Michel ,   the CoRoT team
Published: May 2008

Led by the CNES space agency the CoRoT mission is born from a joint effort of France, Austria, Belgium, Brazil, Germany, Spain and ESA. In orbit around the Earth, CoRoT started its first observations in February 2007 and is, now, regularly producing ten thousand light-curves with a very high accuracy. Performances are better than expected and some Hot Jupiters have already been detected in the raw data. Once the fully corrected data will be delivered, much smaller transits should be detected giving access to the hot Neptunes and the big Terrestrial planet families. We briefly describes the status of the mission, the inflight performance and the ground based program follow up strategy. We also present some preliminary results issued from a first analysis of the data.
Finding Earth-size planets in the habitable zone: theKepler Mission
Authors: Borucki William , Koch David , Basri Gibor , Batalha Natalie , Brown Timothy , Caldwell Douglas , Christensen-Dalsgaard Jørgen , Cochran William , Dunham Edward , Gautier Thomas N. , Geary John , Gilliland Ronald , Jenkins Jon , Kondo Yoji , Latham David , Lissauer Jack J. , Monet David
Published: May 2008

TheKepler Missionis a space-based mission whose primary goal is to detect Earth-size and smaller planets in the habitable zone of solar-like stars. The mission will monitor more than 100,000 stars for transits with a differential photometric precision of 20 ppm at V=12 for a 6.5 hour transit. It will also provide asteroseismic results on several thousand dwarf stars. It is specifically designed to continuously observe a single field of view of greater than 100 square degrees for 3.5 or more years.

This overview describes the mission design, its goals and capabilities, the measured performance for those photometer components that have now been tested, the Kepler Input Catalog, an overview of the analysis pipeline, the plans for the Follow-up Observing Program to validate the detections and characterize the parent stars, and finally, the plans for the Guest Observer and Astrophysical Data Program.
Extrasolar planet detections with gravitational microlensing
Authors: Mao Shude , Kerins Eamonn , Rattenbury Nicholas J.
Published: May 2008

Microlensing light curves due to single stars are symmetric and typically last for a month. So far about 4000 microlensing events have been discovered in real-time, the vast majority toward the Galactic centre. The presence of planets around the primary lenses induces deviations in the usual light curve which lasts from hours (for an Earth-mass [M⊕] planet) to days (for a Jupiter-mass [Mj] planet). Currently the survey teams, OGLE and MOA, discover and announce microlensing events in real-time, and follow-up teams (together with the survey teams) monitor selected events intensively (usually with high magnification) in order to identify anomalies caused by planets. So far four extrasolar planets have been discovered using the microlensing technique, with half a dozen new planet candidates identified in 2007 (yet to be published). Future possibilities include a network of wide-field 2m-class telescopes from the ground (which can combine survey and follow-up in the same setup) and a 1m-class survey telescope from space.
Microlensing search for extrasolar planets: observational strategy, discoveries and implications
Authors: Cassan Arnaud , Sumi Takahiro , Kubas Daniel
Published: May 2008

Microlensing has proven to be a valuable tool to search for extrasolar planets of Jovian- to Super-Earth-mass planets at orbits of a few AU. Since planetary signals are of very short duration, an intense and continuous monitoring is required. This is achieved by ground-based networks of telescopes (PLANET/RoboNET, μFUN) following up targets, which are identified as microlensing events by single dedicated telescopes (OGLE, MOA). Microlensing has led to four already published detections of extrasolar planets, one of them being OGLE 2005-BLG-390Lb, a planet of only ∼5.5M⊕orbiting its M-dwarf host star at ∼2.6 AU. Very recent observations (May–September 2007) provided four more planetary candidates, still under study, that will double the number of detections. For non-planetary microlensing events observed from 1995 to 2006 we compute detection efficiency diagrams, which can then be used to derive an estimate of the Galactic abundance of cool planets in the mass regime from Jupiters to Sub-Neptunes.
A HET search for planets around evolved stars
Authors: Niedzielski Andrzej , Wolszczan Alex
Published: May 2008

We present our ongoing survey of ∼1000 GK-giants with the 9.2-m Hobby-Eberly Telescope in search for planets around evolved stars. The stars selected for this survey are brighter than 11 mag and are located in the section of the HR-diagram, which is approximately delimited by the main sequence, the instability strip, and the coronal dividing line. We use the High Resolution Spectrograph to obtain stellar spectra for radial velocity measurements with a 4-6 m s−1 precision. So far, the survey has discovered a planetary-mass companion to the K0-giant HD 17092, and it has produced a number of plausible planet candidates around other stars. Together with other similar efforts, our program provides information on planet formation around intermediate mass main sequence-progenitors and it will create the experimental basis with which to study dynamics of planetary systems around evolving stars.
A Korea-Japan planet search program: Current status and discovery of a brown dwarf candidate
Authors: Omiya Masashi , Izumiura Hideyuki , Sato Bun'ei , Yoshida Michitoshi , Kambe Eiji , Toyota Eri , Urakawa Seitaro , Masuda Seiji , Takada-Hidai Masahide , Han Inwoo , Kim Kang-Min , Lee Byeong-Cheol , Yoon Tae Seog
Published: May 2008

Since 2005, we have been carrying out a precise radial velocity survey of about 190 intermediate-mass (1.5-5 M⊙) G and K giants at Bohyunsan Optical Astronomy Observatory (BOAO) in Korea and Okayama Astrophysical Observatory (OAO) in Japan, which aims to reveal statistical properties of planetary systems around intermediate-mass stars. We have finished the first screening of 120 stars so far and have identified 5 candidates with large periodic radial velocity variations. One of the candidates turned out to be orbited by a brown dwarf mass companion with minimum mass of 37.6 MJup and semimajor axis of 1.71 AU. The primary star has a mass of 3.9 M⊙, which ranks among the most massive stars with substellar companions. Our discovery may support the current view obtained from results of planet searches around intermediate-mass stars that massive substellar companions tend to form around massive stars.
Photometric follow-up observation of some SuperWASP transiting planet candidates
Authors: Gu Sheng-hong , Cameron Andrew Collier , Wang Xiao-bin , Zhang Li-yun , Fang Xiang-song , Li Xue-jing
Published: May 2008

Three SuperWASP transiting planet candidates were observed through R or I filters using the 1-meter telescope and CCD camera of Yunnan Observatory from 2006 to 2007. The relative photometric data were corrected for the systematic errors by means of Tamuz et al. (2005) and Collier Cameron et al. (2006)'s algorithms. The resulting light curves demonstrate that one of three targets is a potential exoplanet candidate, which is worthy to perform further follow-up observation to clarify.
Several problems of exoplanetary orbits determination from radial velocity observations
Authors: Baluev Roman V.
Published: May 2008

Existing algorithms of analysis of radial velocity time series are improved for the purposes of extrasolar planets detection and characterizing. Three important effects are considered: the poorly known radial velocity jitter, periodic systematic errors, and statistical bias due to non-linearity of models. Mathematical tools to account for these effects are developed and applied to a number of real planetary systems. In particular, it is shown that two outer planets of HD37124 are likely trapped in the 2/1 resonance. The dwarf star GJ876 may host an extra, Neptune-mass, planet which is in resonance with two giant planets in this system.
Selection effects in Doppler velocity planet searches
Authors: O'Toole Simon , Tinney Chris , Jones Hugh
Published: May 2008

The majority of extra-solar planets have been discovered by measuring the Doppler velocities of the host star. Like all exoplanet detection methods, the Doppler method is rife with observational biases. Before any robust comparison of mass, orbital period and eccentricity distributions can be made with theory, a detailed understanding of these selection effects is required, something which up to now is lacking. We present here a progress report on our analysis of the selection effects present in Anglo-Australian Planet Search data, including the methodology used and some preliminary results.
On uncertainty of Jupiter's core mass due to observational errors
Authors: Hori Yasunori , Sano Takayoshi , Ikoma Masahiro , Ida Shigeru
Published: May 2008

The origins of extrasolar gas giant planets have been discussed, based on our understanding of the gas giant planets in the solar system, Jupiter and Saturn. However, how Jupiter and Saturn formed is still uncertain because of the uncertainty in their interiors, especially the core mass (Mc). The uncertainty in Mc is partly due to those in observational data such as gravitational moments (J2n), equatorial radius (Req) and 1-bar temperatures (T1bar). New frontiers mission to Jupiter by NASA (JUNO) launched in 2011 is expected to reduce the observational errors. However, it is not necessarily clear yet which observational uncertainty dominates and how accurate observation is needed to constrain Mc enough to know the origin of Jupiter. Thus, modeling the interior of Jupiter, we evaluate each effect on Mc and required precision. We have found that the observational error of 5% in T1bar yields an error of several M⊕ in Mc. We have also found that the values of J6 of our successful models are confined in a narrow range compared to its observational error. This implies that comparison between the values of J6 of our successful models and the J6 value obtained from JUNO mission helps us to know whether the present theoretical model is valid.
Tidal evolution of close-in extra-solar planets
Authors: Jackson Brian , Greenberg Richard , Barnes Rory
Published: May 2008

The distribution of eccentricities e of extra-solar planets with semi-major axes a > 0.2 AU is very uniform, and values for e are generally large. For a < 0.2 AU, eccentricities are much smaller (most e < 0.2), a characteristic widely attributed to damping by tides after the planets formed and the protoplanetary gas disk dissipated. We have integrated the classical coupled tidal evolution equations for e and a backward in time over the estimated age of each planet, and confirmed that the distribution of initial e values of close-in planets matches that of the general population for reasonable tidal dissipation values Q, with the best fits for stellar and planetary Q being ∼ 105.5 and ∼ 106.5, respectively. The current small values of a were only reached gradually due to tides over the lifetimes of the planets, i.e., the earlier gas disk migration did not bring all planets to their current orbits. As the orbits tidally evolved, there was substantial tidal heating within the planets. The past tidal heating of each planet may have contributed significantly to the thermal budget that governed the planet's physical properties, including its radius, which in many cases may be measured by observing transit events. Here we also compute the plausible heating histories for a few planets with anomalously large measured radii, including HD 209458 b. We show that they may have undergone substantial tidal heating during the past billion years, perhaps enough to explain their large radii. Theoretical models of exoplanet interiors and the corresponding radii should include the role of large and time-variable tidal heating. Our results may have important implications for planet formation models, physical models of “hot Jupiters”, and the success of transit surveys.
SPH simulations of star/planet formation triggered by cloud-cloud collisions
Authors: Kitsionas Spyridon , Whitworth Anthony P. , Klessen Ralf S.
Published: May 2008

We present results of hydrodynamic simulations of star formation triggered by cloud-cloud collisions. During the early stages of star formation, low-mass objects form by gravitational instabilities in protostellar discs. A number of these low-mass objects are in the sub-stellar mass range, including a few objects of planetary mass. The disc instabilities that lead to the formation of low-mass objects in our simulations are the product of disc-disc interactions and/or interactions between the discs and their surrounding gas.
Planet formation around intermediate mass stars
Authors: Kretke Katherine A. , Lin D. N. C. , Turner Neal J.
Published: May 2008

We present a mechanism by which gas giants form efficiently around intermediate mass stars. MRI-driven turbulence effectively drives angular momentum transport in regions of the disk with sufficiently high ionization fraction. In the inner regions of the disk, where the midplane temperature is above ∼1000K, thermal ionization effectively couples the disk to the magnetic field, providing a relatively large viscosity. A pressure maximum will develop outside of this region as the gaseous disk approaches a steady-state surface density profile, trapping migrating solid material. This rocky material will coagulate into planetesimals which grow rapidly until they reach isolation mass. Around intermediate mass stars, viscous heating will push the critical radius for thermal ionization of the midplane out to around 1 AU. This will increase the isolation mass for solid cores. Planets formed here may migrate inwards due to type II migration, but they will induce the formation of subsequent giant planets at the outer edge of the gap they have opened. In this manner, gas giants can form around intermediate mass stars at a few AU.
Retention of protoplanetary cores near the snowline
Authors: Zhang Xiaojia , Kretke Katherine , Lin D. N. C.
Published: May 2008

Suppression of type I migration is essential for the retention of protoplanetary cores which are sufficiently massive to accrete gas in their nascent disks and evolve into gas giant planets. We explore here the possibility that special disk properties at the snow line may be the dominant process which stalled the type I migration. We simply use a 1-D model to calculate the torque with linear formula and find that, if the surface density jump near snowline is great enough, the migration can be efficiently slowed down or even halted. This mechanism offers an explanation to the observed peak, at 2–3 AU, in the extra solar planets' semi major axis distribution.