bluuebunny/crossref_metadata_2025 huggingface dataset:
The structural and functional contribution of N‐terminal region and His‐47 on Taiwan cobra phospholipase A2
Authors: Kao Pei‐Hsiu , Chen Ku‐Chung , Lin Shinne‐Ren , Chang Long‐Sen
Published: November 2007

Modification of His‐47 and removal of the N‐terminal octapeptide caused a different effect on the structure of Naja naja atra (Taiwan cobra) phospholipase A2 (PLA2). Unlike native enzyme, Ca2+ induced an alteration in the structural flexibility of His‐modified PLA2. Moreover, the spatial positions of Trp residues in His‐modified PLA2 were not properly rearranged toward lipid–water interface in the presence of Ca2+. CD spectra and fluorescence measurement showed that the dynamic properties of Trp residues and the gross conformation of N‐terminally truncated PLA2 were totally different from native enzyme. Although a precipitous drop in the enzymatic activity was observed with modified PLA2, His‐modified PLA2 and N‐terminally truncated PLA2 retained cytotoxicity on inducing necrotic death of human neuroblastoma SK‐N‐SH cells. Our data suggest that structural perturbations elicited by the chemical modification cause a dissociation of enzymatic activity and cytotoxicity of PLA2. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Crossbar assembly of antibody‐functionalized peptide nanotubes via biomimetic molecular recognition
Authors: Yang Linglu , Nuraje Nurxat , Bai Hanying , Matsui Hiroshi
Published: November 2007

Previously, a large scale assembly of nanowires in a parallel array configuration has been demonstrated, and one type of nanowire could interconnect two electrodes in the high‐wire density. However, to assemble nanowires into practical logic‐gate configurations in integrated circuits, we need more than the parallel assembly of nanowires. For example, when the assembling nanowires are monopolar semiconductors, logic gates such as AND, OR and NOR are to be assembled necessarily from two types of semiconducting nanowires, n‐type and p‐type, and some of these nanowires must cross perpendicularly to form a crossbar geometry for the logical operation. In this paper, the crossbar assembly of antibody‐functionalized peptide nanotubes was demonstrated by a new biomimetic bottom‐up technique. Molecular recognition between antigens and antibodies enabled two types of the antibody‐functionalized bionanotubes to place them onto targeted locations on substrates, where their complementary antigens were patterned. When two rectangular pads of antigens, human IgG and mouse IgG, were patterned perpendicularly on an Au substrate by nanolithography and then the antihuman IgG nanotubes and the antimouse IgG nanotubes were incubated on this substrate in solution, these bionanotubes were attached onto corresponding locations to form the crossbar configuration. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Simultaneous analysis of urinary 4,4′‐methylenebis(2‐chloroaniline) and N‐acetyl 4,4′‐methylenebis(2‐chloroaniline) using solid‐phase extraction and liquid chromatography/tandem mass spectrometry
Authors: Shih Wei‐Chung , Chen Ming‐Feng , Huang Chih‐Chun Jean , Uang Shi‐Nian , Shih Tung‐Shen , Liou Saou‐Hsing , Wu Kuen‐Yuh
Published: November 2007

Analysis of 4,4′‐methylenebis(2‐cholroaniline) (MOCA) or its metabolites in urine has been considered as the appropriate method to assess MOCA exposures through inhalation and skin absorption. MOCA and its metabolite, N‐acetyl 4,4′‐methylenebis(2‐chloroaniline) (acetyl‐MOCA), are analyzed using methods either limited by sensitivity or sample preparation. Therefore, a solid‐phase extraction (SPE) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed to simultaneously analyze MOCA and acetyl‐MOCA in urine to serve as biomarkers for MOCA exposure. Protein was precipitated by using acetonitrile, and SPE were applied to clean up samples to eliminate the matrix effect and to improve the recovery. The limit of quantitation of this method was at 1.0 ng/mL for MOCA and 0.03 ng/mL for acetyl‐MOCA (signal‐to‐noise (S/N) ratio = 10). Urinary MOCA and acetyl‐MOCA levels in MOCA‐exposed workers were analyzed and quantitated to be 191.9 ± 373.2 (mean ± standard deviation (SD)) and 11.79 ± 23.8 ng/mL (N = 54) with the median values 38.6 and 1.8 ng/mL, respectively. MOCA concentrations are significantly correlated with their corresponding acetyl‐MOCA levels in urine (Spearman correlation coefficient r = 0.916, p < 0.001). These results show that this method has been successfully developed and provides high‐throughput potential to analyze MOCA and acetyl‐MOCA to serve as exposure biomarkers for future study of the potential health effects associated with MOCA exposures. Copyright © 2007 John Wiley & Sons, Ltd.
Absolute and relative quantification of sheep brain prion protein (PrP) allelic variants by matrix‐assisted laser desorption/ionisation time‐of‐flight mass spectrometry
Authors: Morel Nathalie , Andréoletti Olivier , Grassi Jacques , Clément Gilles
Published: November 2007

Transmissible spongiform encephalopathies (TSEs) are characterised by the accumulation in the tissues of affected individuals of an abnormal form (PrPSc) of a protein naturally produced by the host, the cellular prion protein (PrPC). In sheep, susceptibility to TSEs is tightly controlled by polymorphism at positions 136 (A or V), 154 (R or H) and 171 (R or Q) of the Prnp gene encoding the prion protein (PrP). Quantification of PrP variants at positions 136, 154 and 171 can be achieved by matrix‐assisted laser desorption/ionisation time‐of‐flight (MALDI‐TOF) mass spectrometric analysis of the respective peptides 114–139, 152–159 and 160–171 obtained after tryptic digestion of the PrP protein. In this study we quantified the tryptic peptide 114–139 containing the first polymorphic site. Quantification was either relative, between variants of this peptide, or absolute with respect to the C‐terminally 18O‐labelled peptide obtained by hydrolysing known amounts of recombinant protein with trypsin in HO. After purification of PrPC and PrPSc from the brain of two heterozygous sheep carrying either the ARQ/VRQ or ARR/VRQ genotypes, the proportion of each variant was measured. In the ARQ/VRQ animal, while both variants were equally represented in the normal isoform, the VRQ variant was predominantly found in the abnormal PrP protein, suggesting dissimilar behaviour of the two variants in the pathological process. The situation was even more contrasted in the ARR/VRQ animal where PrPSc was solely composed of the VRQ variant. These two examples clearly illustrate the value of MALDI‐TOF analysis, combined with appropriate immunopurification techniques, in seeking a precise understanding of the influence of PrP polymorphisms on TSE pathogenesis. Copyright © 2007 John Wiley & Sons, Ltd.
Invariance in Measurement and Prediction Revisited
Authors: Millsap Roger E.
Published: November 2007

Borsboom (Psychometrika, 71:425–440, 2006) noted that recent work on measurement invariance (MI) and predictive invariance (PI) has had little impact on the practice of measurement in psychology. To understand this contention, the definitions of MI and PI are reviewed, followed by results on the consistency between the two forms of invariance in the general case. The special parametric cases of factor analysis (strict factorial invariance) and linear regression analyses (strong regression invariance) are then described, along with findings on the inconsistency between the two forms of invariance in this context. Two numerical examples of inconsistency are reviewed in detail. The impact of violations of MI on accuracy of selection is illustrated. Finally, reasons for the slow dissemination of work on invariance are discussed, and the prospects for altering this situation are weighed.
Phaseolin type and heat treatment influence the biochemistry of protein digestion in the rat intestine
Authors: Montoya Carlos A. , Leterme Pascal , Beebe Stephen , Souffrant Wolfgang B. , Mollé Daniel , Lallès Jean-Paul
Published: November 2007

The study aimed to investigate thein vivodigestion ofPhaseolus vulgarisphaseolin types differing in their subunit pattern composition. Diets contained either casein as the sole source of protein or a mixture (1:1) of casein and pure Sanilac (S), Tendergreen (T) or Inca (I) phaseolin either unheated or heated. Rats were fed for 11 d with the experimental diets. Their ileal content and mucosa were collected and prepared for electrophoresis, Western blotting, densitometry and MS. Differences in digestion among native phaseolin types were observed for intact phaseolin at molecular weights (MW) of 47–50·5 kDa and for an undigested fragment at MW of 19–21·5 kDa in ileal digesta. In both cases, the concentration of these protein bands was lower for I phaseolin than for S or T phaseolin (P < 0·05). In the mucosa, the concentration of a protein band at MW of 20·5–21·5 kDa was lower for S phaseolin as compared to T or I phaseolin (P < 0·001). The presence of phaseolin subunits and their fragments was confirmed by Western blotting. MS analysis revealed the presence of undigested α and β subunit fragments from phaseolin and endogenous proteins (anionic trypsin I and pancreatic α-amylase) in ileal digesta. Thermal treatment improved digestion (P < 0·01), acting on both dietary and endogenous protein components. In conclusion, this study provides evidence for differences in intestinal digestion among phaseolin types, S phaseolin being more resistant and I phaseolin more susceptible. These differences were affected by the origin of the phaseolin subunit precursor. Heat treatment enhanced phaseolin digestion.
Nutrient utilisation and intestinal fermentation are differentially affected by the consumption of resistant starch varieties and conventional fibres in pigs
Authors: Rideout Todd C. , Liu Qiang , Wood Peter , Fan Ming Z.
Published: November 2007

This study examined the influence of different resistant starch (RS) varieties and conventional fibres on the efficiency of nutrient utilisation and intestinal fermentation in pigs. Thirty-six pigs (30 kg) were fed poultry meal-based diets supplemented with 10 % granular resistant corn starch (GCS), granular resistant potato starch (GPS), retrograded resistant corn starch (RCS), guar gum (GG) or cellulose for 36 d according to a completely randomised block design. Distal ileal and total tract recoveries were similar (P>0·05) among the RS varieties. Distal ileal starch recovery was higher (P < 0·05) in pigs consuming the RS diets (27–42 %) as compared with the control group (0·64 %). Consumption of GCS reduced (P < 0·05) apparent total tract digestibility and whole-body retention of crude protein in comparison with the control group. Consumption of GPS reduced (P < 0·05) total tract Ca digestibility and whole-body retention of Ca and P compared with the control group. However, consumption of RCS increased (P < 0·05) total tract Ca digestibility compared with the control group. Caecal butyrate concentration was increased (P < 0·05) following consumption of RCS and GG in comparison with the control group. Consumption of all the RS varieties reduced (P < 0·05) caecal indole concentrations compared with the control. Caecal butyrate concentrations were positively correlated (P < 0·05;r0·63–0·83) with thermal properties among the RS varieties. We conclude that nutrient utilisation and intestinal fermentation are differentially affected by the consumption of different RS varieties and types of fibres. Thermal properties associated with different RS varieties may be useful markers for developing RS varieties with specific functionality.
Pyrite framboids interpreted as microbial colonies within the PermianZoophycosspreiten from southeastern Australia
Authors: GONG YI-MING , SHI GUANG R. , WELDON ELIZABETH A. , DU YUAN-SHENG , XU RAN
Published: November 2007

Two types of pyrite framboids (PF, probably sulphate-reducing bacteria) have been found within theZoophycosspreiten, hosted in the Guadalupian (Middle Permian) glaciomarine greywacke of the Westley Park Sandstone Member within the Broughton Formation from the southern Sydney Basin of southeastern Australia. They are composed of non-sheathed (PF1) and sheathed (PF2) sub-micron balls, respectively. Chemically, the sub-micron balls consist of iron, sulphur, carbon and oxygen. Both PF1 and PF2 occur in rhythmic alternation within the thick, light-grey and thin, dark-grey minor lamellae ofZoophycosspreiten. The framboids from the minor lamellae are highly abundant and occur in an orderly arrangement of equal density and in a good state of preservation. WithinZoophycosspreiten no homogeneous filling, fecal pellets, or any sign of re-exploitation of the minor lamellae have been recognized. No similar framboids have been observed outsideZoophycosspreiten. Therefore, the framboids are interpreted as the pyritized remains of microbial colonies withinZoophycosspreiten. The traceZoophycoswould be a multifunctional garden that may have been carefully constructed by theZoophycosmaker, where different microbial colonies were orderly and carefully planted and cultured within different minor lamellae. Further, it is proposed that theZoophycosmaker had a symbiotic relationship with microbial colonies on the mutual basis of food supply and redox conditions. The fact that the overlying spreiten cut the underlying ones indicates that theZoophycosfrom the study area is of an upward construction. The rhythmic alternation of both the thick, light-grey and thin, dark-grey minor lamellae withinZoophycosspreiten may be suggestive of a gardening manner of theZoophycosmaker responding to the warm and cold changes, food supply in pulses and variations of sedimentation rate for planting and culturing microbial colonies under the conditions of a glaciomarine environment at the high latitudes.
Effect of metabolizable protein intake on rates of plasma leucine turnover and protein synthesis in heifers
Authors: SANO H. , KAJITA M. , ITO M. , FUJITA T. , TAKAHASHI A.
Published: November 2007

An isotope dilution method using [1-13C]leucine (Leu) infusion together with open-circuit calorimetry was applied to determine the effect of metabolizable protein (MP) intake on rates of plasma Leu turnover and whole body protein synthesis (WBPS) in six heifers. WBPS rate was estimated from rate of plasma Leu turnover and Leu oxidation to carbon dioxide. The experiment consisted of three levels of MP intake and was conducted in a two 3×3 Latin square designs of three 21-day periods. The experimental diet consisted of mixed hay, maize and soybean meal. Dietary MP intake of each dietary treatment was 4·3, 4·5 and 4·9 g/kg BW0·75/day by changing maize and soybean meal weights. Metabolizable energy (ME) intake was similar for all dietary treatments. When plasma α-[1-13C]keto-isocaproic acid enrichments were used as markers indicating intracellular Leu enrichments, plasma Leu turnover rate (LeuTR) increased (P=0·012) and WBPS tended to increase (P=0·091) as MP intake increased. In contrast, plasma LeuTR and WBPS were not influenced if plasma [1-13C]Leu was taken to indicate intracellular Leu enrichments. Total and plasma Leu oxidation rates did not change but intracellular Leu oxidation increased (P=0·044) with increasing MP intake. In heifers, it is suggested that rates of plasma Leu turnover and WBPS are influenced by dietary MP intake, independent of ME intake, although the change in MP intake was relatively small.
Survival of Trichinella papuae muscle larvae in a pig carcass maintained under simulated natural conditions in Papua New Guinea
Authors: Owen Ifor L. , Reid Simon A.
Published: November 2007

In Papua New Guinea, Trichinella papuae, a non-encapsulated species, is circulating among wild and domestic pigs and saltwater crocodiles. Since an important phase of the life cycle of nematodes of the genus Trichinella is the time of survival of infective larvae in decaying muscle tissues of the hosts, the carcass of a pig, experimentally infected with larvae of T. papuae, was exposed to the environmental conditions of Papua New Guinea to establish how long these larvae would survive and remain infective to a new host. Larvae retained their infectivity in the pig carcass up to 9 days after slaughtering, during which time the temperature within the carcass reached 35.0°C on 2 days; the average relative humidity was 79.0%. A low number of larvae survived up to day 14 after the pig was killed, when the carcass temperature reached 38.0°C, but they lost their infectivity to laboratory mice. This result suggests that the larvae of T. papuae can survive in a tropical environment for a time, favouring their transmission to a new host in spite of the lack of a collagen capsule.
Efficacy of the nematode-trapping fungusDuddingtonia flagransagainst infections byHaemonchusandTrichostrongylusspecies in lambs at pasture
Authors: Rocha R.A. , Araújo J.V. , Amarante A.F.T.
Published: November 2007

The efficacy of the nematode-trapping fungusDuddingtonia flagransagainst infections by trichostrongyle nematodes in sheep was assessed throughout 6 months. Twenty Ile de France lambs were divided into two groups (control and treated groups), which were kept in separate pastures. Animals of the treated group were fed withD. flagranstwice a week (Tuesdays and Fridays). Pellets were prepared with the fungus mycelia in liquid culture medium and contained approximately 20% fungus. They were mixed with the animals' diet at a concentration of 1 g pellet per 10 kg live weight. Faecal egg counts (FEC), packed cell volume (PCV), total serum protein and the animals' body weight were determined fortnightly from 7 October 2005 to 24 March 2006. Comparison of such parameters between groups showed no significant differences (P> 0.05), except on 10 February 2006, when the control group presented a higher mean FEC than the treated group (P<  0.05). Feeding sheep with pellets containingD. flagranshad no benefit to the prophylaxis of nematode infections under the experimental conditions used in the present study.
Endoscopic sinus surgery for the anterior maxillary sinus, using a 135° reflective CO2 laser
Authors: Sato K
Published: November 2007

Objectives:

Endoscopic sinus surgery has been widely performed to treat nose and paranasal diseases. However, it is difficult to manipulate anterior wall lesions of the maxillary sinus using conventional surgical instruments. This paper presents a method of performing endoscopic surgery for anterior wall lesions of the maxillary sinus, using a 135° reflective CO2 laser.

Method:

A CO2 laser with a 135° reflective tip on the pipe-guide handpiece and a CO2 laser angulated to the same degree were used. The pipe-guide handpiece with reflective tip was inserted into the nasal cavity and the base of the maxillary sinus anterior wall lesion was vaporised and removed via an enlarged natural ostium. During the procedure, the maxillary antrum was visualised with a 70° endoscope. Ten cases of maxillary sinus anterior wall lesion underwent this surgical procedure.

Results:

In all cases, the base of the maxillary sinus anterior wall lesion was removed completely and recurrence avoided.

Conclusion:

This method is a reliable procedure enabling endoscopic sinus surgery for anterior wall lesions of the maxillary sinus.
Modified Korteweg–de Vries–Zakharov–Kuznetsov solitons in symmetric two-temperature electron–positron plasmas
Authors: LAZARUS I. J. , BHARUTHRAM R. , HELLBERG M. A.
Published: November 2007

Solitary waves are investigated in a magnetized electron–positron plasma consisting of equal hot and cool components of each species. The hot components have a Boltzmann distribution and the cool components are described by the fluid equations. A modified Korteweg–de Vries–Zakharov–Kuznetsov equation governing the oblique propagation of nonlinear electrostatic modes is derived using the reductive-perturbation technique. Soliton amplitudes are studied as a function of plasma parameters such as the particle number densities and the temperatures. Such results may be of relevance to the magnetosphere of pulsars.
ALeishmania(L.)amazonensisATP diphosphohydrolase isoform and potato apyrase share epitopes: antigenicity and correlation with disease progression
Authors: COIMBRA E. S. , GONÇALVES-DA-COSTA S. C. , COSTA B. L. S. , GIAROLA N. L. L. , REZENDE-SOARES F. A. , FESSEL M. R. , FERREIRA A. P. , SOUZA C. S. F. , ABREU-SILVA A. L. , VASCONCELOS E. G.
Published: November 2007

ALeishmania(Leishmania)amazonensisATP diphosphohydrolase isoform was partially purified from plasma membrane of promastigotes by preparative non-denaturing polyacrylamide gel electrophoresis. SDS-PAGE followed by Western blots developed with polyclonal anti-potato apyrase antibodies identified diffuse bands of about 58–63 kDa, possibly glycosylated forms of this protein. By ELISA technique, a significantly higher total IgG antibody level against potato apyrase was found in serum from promastigote-infected mice, as compared to the uninfected mice, confirming both the existence of shared epitopes between the parasite and vegetable proteins, and the parasite ATP diphosphohydrolase antigenicity. By Western blotting, serum from amastigote-infected BALB/c mice recognizes both potato apyrase and this antigenic ATP diphosphohydrolase isoform isolated from promastigotes, suggesting that it is also expressed in the amastigote stage. The infection monitored along a 90-day period in amastigote-infected mice showed reactivity of IgG2a antibody in early steps of infection, while the disappearance of the IgG2a response and elevation of IgG1 antibody serum levels against that shared epitopes were associated with the progression of experimental leishmaniasis. This is the first observation of the antigenicity of aL. (L.)amazonensisATP diphosphohydrolase isoform, and of the ability of cross-immunoreactivity with potato apyrase to differentiate serologically stages of leishmaniasis in infected mice.
Parasite variation and the evolution of virulence in a Daphnia-microparasite system
Authors: LITTLE T. J. , CHADWICK W. , WATT K.
Published: November 2007

Understanding genetic relationships amongst the life-history traits of parasites is crucial for testing hypotheses on the evolution of virulence. This study therefore examined variation between parasite isolates (the bacterium Pasteuria ramosa) from the crustacean Daphnia magna. From a single wild-caught infected host we obtained 2 P. ramosa isolates that differed substantially in the mortality they caused. Surprisingly, the isolate causing higher early mortality was, on average, less successful at establishing infections and had a slower growth rate within hosts. The observation that within-host replication rate was negatively correlated with mortality could violate a central assumption of the trade-off hypothesis for the evolution of virulence, but we discuss a number of caveats which caution against premature rejection of the trade-off hypothesis. We sought to test if the characteristics of these parasite isolates were constant across host genotypes in a second experiment that included 2 Daphnia host clones. The relative growth rates of the two parasite isolates did indeed depend on the host genotype (although the rank order did not change). We suggest that testing evolutionary hypotheses for virulence may require substantial sampling of both host and parasite genetic variation, and discuss how selection for virulence may change with the epidemiological state of natural populations and how this can promote genetic variation for virulence.
Experimental evidence for a motivational origin of cognitive impairment in major depression
Authors: Scheurich A. , Fellgiebel A. , Schermuly I. , Bauer S. , Wölfges R. , Müller M. J.
Published: November 2007

Background

Diagnostic criteria and empirical evidence support the existence of cognitive deficits in depression. However, depressed mood, loss of interest and low self-efficacy might influence cognitive performance.

Method

Goal-setting instructions were used to promote motivation in depressed patients and control subjects during neuropsychological assessment. The resulting performance was compared with performance using standard instructions. Sixty in-patients with non-psychotic unipolar depression and 60 age- and education-matched healthy control subjects were assessed with standard neuropsychological tests [the Auditory Verbal Learning Test (AVLT), the Digit Symbol Test (DST), the Regensburg Word Fluency Test (RWT), and the Number Combination Test (Zahlen-Verbindungs-Test, ZVT)] using either goal-setting or standard test instructions.

Results

Depressed patients showed lower baseline performance and lower generalized self-efficacy (p<0.0005) than controls. However, goal-setting instructions significantly improved patients' memory performance by 10% [AVLT:F(5, 54)=3.611,p=0.007] and psychomotor performance by 13% [ZVT:F(3, 56)=3.667,p=0.017]. Consequently, patients and control subjects demonstrated similar results when goal-setting instructions were applied. Goal-setting instructions showed a statistical trend, increasing patients' performance in the DST by 12% [F(1, 58)=2.990,p=0.089], although their verbal fluency measured by the RWT did not increase. No significant correlations of increased performance with generalized self-efficacy were found.

Conclusions

Cognitive deficits in depressed patients are influenced by motivational shortcomings. Because generalized self-efficacy failed to correlate to increased test performance, future research needs to disentangle the effective components of goal-setting instructions. Task-specific self-efficacy as well as enhancement of task-focused attention might underlie the significant goal-setting effect in depressed patients.
Kinematic enveloping grasp planning method for robotic dexterous hands and three-dimensional objects
Authors: Salimi Shahram , Bone Gary M.
Published: November 2007

Three-dimensional (3D) enveloping grasps for dexterous robotic hands possess several advantages over other types of grasps. This paper describes a new method for kinematic 3D enveloping grasp planning. A new idea for grading the 3D grasp search domain for a given object is proposed. The grading method analyzes the curvature pattern and effective diameter of the object, and grades object regions according to their suitability for grasping. A new approach is also proposed for modeling the fingers of the dexterous hand. The grasp planning method is demonstrated for a three-fingered, six degrees-of-freedom, dexterous hand and several 3D objects containing both convex and concave surface patches. Human-like high-quality grasps are generated in less than 20 s per object.
Outbreak of group A streptococcal throat infection: don't forget to ask about food
Authors: FALKENHORST G. , BAGDONAITE J. , LISBY M. , MADSEN S. B. , LAMBERTSEN L. , OLSEN K. E. P. , MØLBAK K.
Published: November 2007

We report a large foodborne outbreak due to group A streptococci (GAS), which caused acute tonsillo-pharyngitis in 200–250 patrons of a company canteen in Copenhagen, Denmark, in June 2006. A retrospective cohort study of canteen users showed that consumption of cold pasta was associated with an increased risk of illness (attack rate 68%, risk ratio 4·1,P<0·0001). Indistinguishable GAS strains (emm89, T-type 3/13/B3264) were cultured from three cases and a cook, who had prepared the pasta. To our knowledge, pasta has previously only twice been incriminated as the source of a GAS outbreak. Only six foodborne GAS outbreaks have been reported in Europe since 1970, four of them in Sweden or Denmark. This geographical clustering suggests that foodborne GAS outbreaks are probably under-recognized elsewhere.
Short Note: A method for sexing the chicks of Antarctic shags
Authors: Casaux R. , Ramón A. , Baroni A.
Published: November 2007

Several studies have been carried out during the last fifteen years on reproduction, population dynamics and diet of the Antarctic shag, Phalacrocorax bransfieldensis Murphy, at different localities in the South Shetland Islands (reviewed in Casaux & Barrera-Oro 2006). In both the colonies studied and in other colonies counted we observed that the number of breeding pairs was steadily decreasing (Casaux & Barrera-Oro 2006). Casaux & Baroni (2002) had earlier suggested that such a decreasing trend might be related, at least partially, to a marked decrease in the inshore populations of two fish prey species, the marbled notothen Notothenia rossii Richardson and the humphead notothen Gobionotothen gibberifrons Lönnberg (Barrera-Oro et al. 2000), which had been studied over a period of 19 years in coastal waters of the South Shetland Islands. Exactly how a reduction in prey availability affects the shag populations (e.g. migration of breeders to other colonies in the area or to new breeding areas, a decrease in the rate of recruitment, an increase in adult mortality, variation in the age at first breeding, etc) is not clear. To investigate this, we started a banding programme at Nelson Island, South Shetland Islands. We postulated that the processes might operate with different intensities on individuals of different sexes, so all individuals in each population studied needed to be sexed. This posed problems for chicks which have monomorphic plumage and no differences in vocalisations (Casaux & Baroni 2000), so that the normal methods for sexing in the field would not work. As most of the external morphological characters in the chicks of Antarctic shags have stabilized by 45–50 days old (Casaux 1998), Casaux & Baroni (2000) had suggested that the use of discriminant functions originally developed for adults could be an appropriate method to sex chicks more than 50 days old.
Two-Parameter Poisson–Dirichlet Measures and Reversible Exchangeable Fragmentation–Coalescence Processes
Authors: BERTOIN JEAN
Published: November 2007

We show that for 0<α<1 and θ>−α, the Poisson–Dirichlet distribution with parameter (α, θ) is the unique reversible distribution of a rather natural fragmentation–coalescence process. This completes earlier results in the literature for certain split-and-merge transformations and the parameter α = 0.
Dismantling Sparse Random Graphs
Authors: JANSON SVANTE , THOMASON ANDREW
Published: November 2007

We consider the number of vertices that must be removed from a graphGin order that the remaining subgraph have no component with more thankvertices. Our principal observation is that, ifGis a sparse random graph or a random regular graph onnvertices withn→ ∞, then the number in question is essentially the same for all values ofkthat satisfy bothk→ ∞ andk=o(n).
Phase Transformation and Segregation to Lattice Defects in Ni-Base Superalloys
Authors: Blavette Didier , Cadel Emmanuel , Pareige Cristelle , Deconihout Bernard , Caron Pierre
Published: November 2007

Nanostructural features of nickel-base superalloys as revealed by atom probe field ion microscopy (APFIM) and atom probe tomography (APT) are reviewed. The more salient information provided by these techniques is discussed through an almost exhaustive analysis of literature over the last 30 years. Atom probe techniques are shown to be able to measure the composition of tiny γ′ precipitates, a few nanometers in size, and to reveal chemical order within these precipitates. Phase separation kinetics in model NiCrAl alloys was investigated with both 3DAP and Monte-Carlo simulation. Results are shown to be in good agreement. Plane by plane analysis of {001} planes of Ni3Al-type γ′ phase makes it possible to estimate the degree of order as well as the preferential sites of various addition elements (Ti, Cr, Co, W, Ta, Re, Ru, etc.) included in superalloys. Clustering effects of Re in the γ solid solution were also exhibited. Due to its ultrahigh depth resolution, the microchemistry of interfaces and grain boundaries can be characterized on an atomic scale. Grain boundaries in Astroloy or N18 superalloys were found to be enriched in B, Mo, and Cr and Al depleted.
Atom Probe Analysis of III–V and Si-Based Semiconductor Photovoltaic Structures
Authors: Gorman Brian P. , Norman Andrew G. , Yan Yanfa
Published: November 2007

The applicability of atom probe to the characterization of photovoltaic devices is presented with special emphasis on high efficiency III–V and low cost ITO/a-Si:H heterojunction cells. Laser pulsed atom probe is shown to enable subnanometer chemical and structural depth profiling of interfaces in III–V heterojunction cells. Hydrogen, oxygen, and phosphorus chemical profiling in 5-nm-thick a-Si heterojunction cells is also illustrated, along with compositional analysis of the ITO/a-Si interface. Detection limits of atom probe tomography useful to semiconductor devices are also discussed. Gaining information about interfacial abruptness, roughness, and dopant profiles will allow for the determination of semiconductor conductivity, junction depletion widths, and ultimately photocurrent collection efficiencies and fill factors.
Discrete choice model in a market with product differentiation: the Argentine pension fund system
Authors: APELLA IGNACIO
Published: November 2007

The objective of the paper is to identify the determinants of the market share of each AFJP and the matrix of direct and cross price elasticities, by using a discrete choice model of product differentiation, based on the random utility theory. The results obtained from the estimation of a simple logit model using a panel of quarterly data between December of 1995 and June of 2006 shows the existence of two competitive mechanisms used by firms: prices and a vector of variables explaining horizontal differentiation, such as quantity of branches and salesman. The estimation of the nested-logit model supports the hypothesis of sequential election, where firms are chosen by their price setting strategies, defining two groups of competitors. Finally, the regulatory change that eliminates fixed commissions provides additional importance to prices signals in consumers' utility.
Investment patterns in Singapore's Central Provident Fund System
Authors: KOH BENEDICT S. K. , MITCHELL OLIVIA S. , TANUWIDJAJA TOTO , FONG JOELLE
Published: November 2007

Rising elderly life expectancies imply the need to accumulate sufficient savings for retirement. This paper investigates the role of recent changes in the investment menu of the Singaporean Central Provident Fund (CPF) system. Our research explores the investment patterns of CPF participants and articulates their implications for policymakers. We find that most investors use their money for housing purchase and default the remainder to the CPF investment pool. The bulk of non-housing saving sits in bank accounts paying a low return. A fraction of workers does elect outside investment products, with high-income earners and males taking more risk than low-income earners and females. Since workers who default their money to the CPF fund receive a guaranteed 2.5% return on the Ordinary Account and 4% on the Special Account, hurdle rates for money market and equity funds are substantial. These high hurdle rates help explain why few CPF account holders invest outside the default government investment pool, though inertia probably explains why many employees let their funds sit in bank accounts earning low interest rates. More attention could be devoted to lowering fund expenses and commissions, including the myriad of fees, expenses, loads, and wrap charges; it might also be beneficial to streamline and rationalize the investment menu offered to participants.
Mesoscale‐resolving simulations of summer and winter bora events in the Adriatic Sea
Authors: Cushman‐Roisin Benoit , Korotenko Konstantin A.
Published: November 2007

This paper presents simulations of the Adriatic Sea response to two distinct bora wind events, one in summer (11–20 August 2001), when the water is stratified, and the other in winter (11–20 February 2003), when it is vertically homogeneous. The simulations employ the DieCAST model on a 1.2‐min grid (about 2‐km resolution) and resolve the mesoscale variability because the grid size falls below the first baroclinic deformation radius (about 5–10 km) and the model has very low horizontal dissipation. The model is initialized with seasonally averaged temperature and salinity data and spun up with climatological winds. The summer of August 2001 event leads to the generation of a coastal current directed paradoxically to the left of the wind and identified with the summertime Istrian Coastal Countercurrent. Analysis of the physics simulated by the model leads to the conclusion that this current is caused by baroclinic geostrophic adjustment of the Istrian coastal waters following a rapid but strong wind impulse. According to both satellite observations and model simulations, the current persists for more than a week after the bora event. The winter event of February 2003 generates a slightly less complicated situation because the shallow northern Adriatic is then vertically homogeneous, but in situ observations at the time of this particular event permit a comparison of model results with observations and thus an evaluation of the model performance. In particular, the model simulates correctly a series of currents, bifurcations, and confluences of the wind‐driven currents across the northern Adriatic basin. A lesson learned is that a bora event, though generally strong, especially in winter, leaves a legacy that does not obliterate completely what existed prior to the event. In other words, the state of the northern Adriatic basin is fashioned by sequential events, and one bora event may not be viewed in isolation but must be considered as one episode in an unfolding succession of events.
Summary of the CARBOSOL project: Present and retrospective state of organic versus inorganic aerosol over Europe
Authors: Legrand M. , Puxbaum H.
Published: November 2007

Aerosol is an important source of uncertainty concerning the role of the atmosphere in climate forcing. In particular, major gaps exist with respect to its carbonaceous fraction in terms of composition, source apportionment (natural versus anthropogenic), change over the past, and radiative impact. The CARBOSOL project contributes to reduce these uncertainties. CARBOSOL combines a 2‐year study of present‐day carbonaceous aerosol in air and precipitation in western/central Europe with the trends of climatically relevant species in Alpine ice cores. Comparisons between observed atmospheric distributions (present and proxy of past) and transport/chemistry model simulations allow to test the accuracy of present and past anthropogenic emission inventories and enable for the first time a comparison of the model results for individual components (primary, secondary, fossil fuel, and biogenic) against data derived from measurements. The net radiative effect of the aerosol load and composition (inorganic/organic) in Europe is evaluated using radiative/chemistry/transport models. This summary paper gives an overview of the CARBOSOL goals, and reports on the key findings as a guide to the results detailed in the papers that follow.
Weak thermal convection within tilted plume conduits
Authors: Sleep Norman H.
Published: November 2007

Shear from flow in the mantle tilts the conduits of mantle plumes. The density stratification at the top of the plume conduit is then unstable in cross section with cold material over hot. This stratification drives cross‐stream convection. Such convection including the Stokes' law rise of the plume conduit through the ambient mantle readily mixes isoviscous thermal plumes with their surroundings. Laboratory experiments by Kerr and Mériaux (2004) indicate that cross‐stream convection is weak within plumes with strongly temperature‐dependent viscosity and significant ∼56 viscosity contrasts. Analogy with stagnant‐lid convection provides scaling relationships with a Rayleigh number for cross‐stream convection within tilted plume conduits. Only material within a factor of a few e of the central viscosity of the plume convects significantly. The scaling analysis shows that the laboratory experiments by Kerr and Mériaux (2004) had the proper parameter range for the Hawaiian plume. The petrological conclusion that the plume conduit has been only mildly stirred by cross‐stream convection is reasonable. Cross‐stream convection is less likely for low‐flux plumes, like Galapagos, than high‐flux plumes and plumes in the deep mantle compared with those in the upper mantle.
On the optimum radar beam angle to minimize statistical estimation error of momentum flux using conjugate beam technique
Authors: Dutta G. , Vinay Kumar P. , Rao P. V. , Ajay Kumar M. C. , Mukarram K. S. , Harshavardhan V. , Rao P. B.
Published: November 2007

Multi beam experiments were conducted using MST radar at Gadanki (13.5°N, 79.2°E) to examine the dependence of statistical estimation error of momentum flux of wind fluctuations on radar beam angle. We find that an optimum angle between 9°–12° with sufficient integration minimizes the error at a value nearly equal to the irreducible error in the troposphere. The balance between the angle dependence of horizontal velocity measurement precision and spatial stationarity seems to decide the optimal beam separation. We also show that the radial velocities obtained by Doppler beam‐swinging method must be appropriately corrected for anisotropy of VHF radio wave scatterers, particularly for lower beam angles, which are found to get affected substantially. Momentum flux of wind fluctuations estimated using low radar beam angles need a longer time of integration to reduce statistical error to its minimum value.
Magnetohydrodynamic simulation of the interaction between two interplanetary magnetic clouds and its consequent geoeffectiveness
Authors: Xiong Ming , Zheng Huinan , Wu S. T. , Wang Yuming , Wang Shui
Published: November 2007

Numerical studies of the interplanetary “multiple magnetic clouds (Multi‐MC)” are performed by a 2.5‐dimensional ideal magnetohydrodynamic (MHD) model in the heliospheric meridional plane. Both slow MC1 and fast MC2 are initially emerged along the heliospheric equator, one after another with different time intervals. The coupling of two MCs could be considered as the comprehensive interaction between two systems, each comprising of an MC body and its driven shock. The MC2‐driven shock and MC2 body are successively involved into interaction with MC1 body. The momentum is transferred from MC2 to MC1. After the passage of MC2‐driven shock front, magnetic field lines in MC1 medium previously compressed by MC2‐driven shock are prevented from being restored by the MC2 body pushing. MC1 body undergoes the most violent compression from the ambient solar wind ahead, continuous penetration of MC2‐driven shock through MC1 body, and persistent pushing of MC2 body at MC1 tail boundary. As the evolution proceeds, the MC1 body suffers from larger and larger compression, and its original vulnerable magnetic elasticity becomes stiffer and stiffer. So there exists a maximum compressibility of Multi‐MC when the accumulated elasticity can balance the external compression. This cutoff limit of compressibility mainly decides the maximally available geoeffectiveness of Multi‐MC because the geoeffectiveness enhancement of MCs interacting is ascribed to the compression. Particularly, the greatest geoeffectiveness is excited among all combinations of each MC helicity, if magnetic field lines in the interacting region of Multi‐MC are all southward. Multi‐MC completes its final evolutionary stage when the MC2‐driven shock is merged with MC1‐driven shock into a stronger compound shock. With respect to Multi‐MC geoeffectiveness, the evolution stage is a dominant factor, whereas the collision intensity is a subordinate one. The magnetic elasticity, magnetic helicity of each MC, and compression between each other are the key physical factors for the formation, propagation, evolution, and resulting geoeffectiveness of interplanetary Multi‐MC.
Longitudinal and seasonal variations in plasmaspheric electron density: Implications for electron precipitation
Authors: Clilverd M. A. , Meredith N. P. , Horne R. B. , Glauert S. A. , Anderson R. R. , Thomson N. R. , Menk F. W. , Sandel B. R.
Published: November 2007

The tilt and offset of the Earth's magnetic field can significantly affect the longitudinal and seasonal distribution of electron density in the plasmasphere. Here we show that for the solar maximum conditions of 1990–1991, the largest annual variation determined from CRRES measurements of plasmaspheric equatorial electron density in the range L = 2.5–5.0 occurs at American longitudes (−60°E), while no annual variation occurs at Asian longitudes (+100°E). Plasmaspheric electron density is larger in December than in June at most longitudes, from −180°E eastward to +20°E. At all other longitudes the density ratio from December to June is very close to 1.0. The largest December/June density ratio is at L = 3.0 at American longitudes (−60°E). At L = 4.5 and above, the annual variation disappears. The lowest electron density values for a given L‐shell occur at American longitudes, in June. Ion densities also show significant annual variations, with similar longitudinal and seasonal characteristics in the case of IMAGE EUV He+ measurements. Atomic mass density measurements calculated using the magnetometer cross‐phase technique show significant seasonal variations but also imply composition changes with longitude. Using the quasilinear PADIE code we calculate the bounce‐averaged diffusion rate of electrons by plasmaspheric hiss with a fixed wave intensity. December to June variations in plasmaspheric density, particularly at American longitudes, drive changes in the wave‐particle interactions, increasing diffusion into the loss cone by a factor of ∼3 at 1 MeV at L = 3.0, thus hardening the electron precipitation spectrum during the southern hemisphere winter (in June).
Remote sensing of ionospheric disturbances associated with energetic particle precipitation using the South Pole VLF beacon
Authors: Chevalier M. W. , Peter W. B. , Inan U. S. , Bell T. F. , Spasojevic Maria
Published: November 2007

The Stanford University VLF beacon transmitter located at South Pole operates at 19.4 kHz, transmitting for 1 min intervals every 15 min throughout the day. The beacon serves as a tool to measure changes in the D region ionospheric conductivity owing to energetic particle precipitation and is capable of providing coverage that spans the Antarctic continent. We present VLF beacon signal amplitude and phase data measured at Palmer Station, Antarctica. Diurnal and seasonal variations are discussed first, followed by analysis of data from two periods of high geomagnetic activity, in July 2004 and in May 2005, with a phase advance and an amplitude depression of the beacon signal (as recorded at Palmer) observed for both cases. Data from the MEPED instrument aboard the NOAA‐16 and 17 POES satellites show an increase in energetic electron (>100 keV) and proton (>16 MeV) precipitation fluxes coincident with the VLF beacon signal perturbations. The fluxes measured on POES are used as an aide to generate profiles of secondary ionization along the great circle path from South Pole to Palmer. These profiles are then applied to a quantitative model of subionospheric VLF signal propagation to estimate the phase and amplitude variations expected. Results indicate that the observed VLF amplitude and phase data are in reasonable agreement with theoretical calculations in both cases, indicating that the model captures the ionospheric disturbance in effect during both of the disturbed periods.