bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of four tobacco‐specific nitrosamines in mainstream cigarette smoke by gas chromatography/ion trap mass spectrometry
Authors: Zhou Jun , Bai Ruoshi , Zhu Yongfa
Published: November 2007

A specific and sensitive method was developed and validated to quantitatively analyze four tobacco‐specific nitrosamines (TSNAs) in the particulate phase of mainstream cigarette smoke. Cigarette smoke particulate matter was collected according to ISO 4387. The particulate matter was extracted with acetic ether, cleaned up with a Supelclean ENVI‐Carb silod‐phase extraction (SPE) cartridge, concentrated under the protection of nitrogen and analyzed by gas chromatography (GC)/ion trap mass spectrometry (MS) with a very‐low‐flow‐loss column (VF‐17 MS) in MSn mode using N‐nitrosopentyl‐3‐picolylamine (NNPA) as an internal standard. TSNAs were identified by chromatographic retention time, matching the spectra of the standards and the samples and the consistency of the ratio of the abundance of the ions detected in the standards and the samples. Limits of detection of each TSNA varied from 0.01 to 0.06 ng/cig. A linear calibration range for this method is large enough to measure TSNA levels in cigarette smoke. The recovery of each TSNA was from 91.5 to 102.7%. The method achieved excellent reproducibility (RSD: 1.8–4.8% for intra‐assay, 3.4–7.1% for inter‐assay). It also shows no evidence of artifact formation. This method is very suitable for the routine detection of TSNAs in mainstream cigarette smoke. Copyright © 2007 John Wiley & Sons, Ltd.
Magnetic resonance imaging‐compatible, three‐degrees‐of‐freedom joystick for surgical robot
Authors: Harja Juha , Tikkanen Jussi , Sorvoja Hannu , Myllylä Risto
Published: November 2007

Background

This paper presents a magnetic resonance (MR) compatible joystick for controlling a surgical robot arm. The surgical robot can be used to assist the surgeon in high precision neurosurgery tasks. Conventional joysticks cannot be used in magnetic resonance imaging (MRI) environments, because they generally contain ferromagnetic materials such as iron, which create distortions in MR images. Moreover, dangerous situations may arise, when an object containing ferromagnetic materials passes through the strong magnetic field of an imaging device. Currents generated by device electronics produce magnetic fields that distort MR images.

Methods

Operation of the joystick described here is based on measuring light intensity. Optical fibres are used for target illumination and for transmitting the reflected light. Their use enables the joystick electronics to be kept at a safe distance from the imaging machine.

Results

Experimental results prove that the joystick can be constructed on the presented operating principle using the designed mechanical structure. When the joystick was placed 15 cm away from the phantom object, it didn't cause any distortion to the MR image.

Conclusions

The developed joystick can be used in an MRI environment. However, further development need to be done in order to avoid losses caused by bending optical fibres. Copyright © 2007 John Wiley & Sons, Ltd.
Extracting physically nonexistent contours
Authors: Yasuda Hiroyuki , Ando Kazuhisa , Ohnishi Noboru , Sugie Noboru
Published: November 2007

A model of the human vision system is proposed which seems to be related to highly reliable extraction of contours from an original image. In other words, an algorithm is proposed for automatically generating physically nonexistent subjective contours. This algorithm consists of the following five steps: extracting physical contours, determining candidate points through which subjective contours pass, determining a direction of subjective contours at each candidate point, determining pairs of candidate points to be connected by subjective contours, and generating curves connecting each pair of candidate points. This algorithm was applied to various figures containing line segments, and it was found that the same contours as the subjective contours perceived by human beings could be generated automatically. Further, this algorithm was applied to a figure of lines consisting only of external contours at which several convex polygons overlap each other. Then, internal contours could be extracted in the overlapping parts of objects and separate constituent polygons.
Estimation of 3‐D shape from shading by using a constraint at zero‐crossing
Authors: Sangaworasil Manas , Kojima Kouichi , Atsuta Kiyoaki , Kondo Shozo
Published: November 2007

This paper describes estimations of the shape of a three‐dimensional (3‐D) object from a gray‐level 2‐D image, i.e., “shape from shading.” The fact that the Ikeuchi‐Horn iterative method produces an error when this is applied to the estimation of an object having a concave surface is shown. A new method using a constraint on a zero‐crossing is proposed which can be applied to such an object. Examples of application of the proposed method are shown to confirm its effectiveness, from a case where several interpretations are possible from a single gray‐level 2‐D image, the proposed method can estimate all of them. Examples of such cases also are shown.
Identification for complicated shape objects by using stochastic fractal variables—categorizing dust particles on LSI wafer surface
Authors: Kamijo Masayoshi , Aihara Shin‐Ichi
Published: November 2007

Improving the yield and stability of LSI wafer production requires that the number of dust particles during every process of the production be decreased. To do this, we must develop a method of identifying dust particles. However, the current method of inspecting LSI wafers depends on human judgment; this makes it difficult to develop an algorithm to identify dust particles with complex shapes because mathematical models of dust particles have not been created. With this study, we propose the so‐called “stochastic fractal variable” to make the mathematical model and identify the dust particles by using the maximum‐likelihood method. Furthermore, we confirm the effectiveness of the identification method we propose by categorizing actual data.
Semiparametric Bayesian analysis of structural equation models with fixed covariates
Authors: Lee Sik‐Yum , Lu Bin , Song Xin‐Yuan
Published: November 2007

Latent variables play the most important role in structural equation modeling. In almost all existing structural equation models (SEMs), it is assumed that the distribution of the latent variables is normal. As this assumption is likely to be violated in many biomedical researches, a semiparametric Bayesian approach for relaxing it is developed in this paper. In the context of SEMs with covariates, we provide a general Bayesian framework in which a semiparametric hierarchical modeling with an approximate truncation Dirichlet process prior distribution is specified for the latent variables. The stick‐breaking prior and the blocked Gibbs sampler are used for efficient simulation in the posterior analysis. The developed methodology is applied to a study of kidney disease in diabetes patients. A simulation study is conducted to reveal the empirical performance of the proposed approach. Supplementary electronic material for this paper is available in Wiley InterScience at http://www.mrw.interscience.wiley.com/suppmat/1097‐0258/suppmat/. Copyright © 2007 John Wiley & Sons, Ltd.
Fast Mass Transport Through Carbon Nanotube Membranes
Authors: Verweij Henk , Schillo Melissa C. , Li Ju
Published: November 2007

The May 19, 2006 issue of Science included a paper by Holt et al.1 on “Fast Mass Transport Through Sub‐2‐Nanometer Carbon Nanotubes”. The paper was also featured on the cover, showing methane molecules translating inside a carbon nanotube (CNT). The authors explained how they prepared 2–6‐μm thin membranes consisting of double‐walled carbon nanotubes (DWNTs) all aligned perpendicular to the apparent membrane surface. These tubes are open at both ends and the space between the tubes is filled with dense Si3N4. Pure gas and water fluxes were measured at room temperature with the application of a small pressure difference. Interpretation of the results led to the conclusion that the membranes showed much higher fluxes than what was estimated from Knudsen gas diffusion and Poiseuille viscous flow models. The membranes have a straight‐channel morphology with a narrow pore‐size distribution and exceptionally smooth pore walls. The unusual geometry and surface properties make it difficult to compare the membrane’s properties with common membranes but there is no question that the mass transport in the aligned DWNTs is fast indeed. To appreciate how fast, we will consider their transport properties starting from the perspective of “conventional” porous membrane technology. Recent molecular dynamics simulations suggest that none of the classic models for gas (Knudsen) and water (Poiseuille) permeation work in a meaningful way for these nanotube membranes, and new models are needed.
Model checking action system refinements
Authors: Smith Graeme , Winter Kirsten
Published: November 2007

Action systems provide a formal approach to modelling parallel and reactive systems. They have a well established theory of refinement supported by simulation-based proof rules. This paper introduces an automatic approach for verifying action system refinements utilising standard CTL model checking. To do this, we encode each of the simulation conditions as a
simulation machine
, a Kripke structure on which the proof obligation can be discharged by checking that an associated CTL property holds. This procedure transforms each simulation condition into a model checking problem. Each simulation condition can then be model checked in isolation, or, if desired, together with the other simulation conditions by combining the simulation machines and the CTL properties.
Taxicab Correspondence Analysis of Contingency Tables with One Heavyweight Column
Authors: Choulakian V.
Published: November 2007

The aim of this paper is to study the analysis of contingency tables with one heavyweight column or one heavyweight entry by taxicab correspondence analysis (TCA). Given that the mathematics of TCA is simpler than the mathematics of correspondence analysis (CA), the influence of one heavyweight column on the outputs of TCA is studied explicitly without recourse to asymptotics as done by Benzécri (Les Cahiers de L’Analyse des Données 4:413–16, 1979). A reweighting of the heavyweight column is proposed, which can also be applied to CA. A real data set is analyzed.
In Vitro Structural and Functional Evaluation of Gold Nanoparticles Conjugated Antibiotics
Authors: Saha Biswarup , Bhattacharya Jaydeep , Mukherjee Ananda , Ghosh AnupKumar , Santra ChittaRanjan , Dasgupta Anjan K , Karmakar Parimal
Published: November 2007

Bactericidal efficacy of gold nanoparticles conjugated with ampicillin, streptomycin and kanamycin were evaluated. Gold nanoparticles (Gnps) were conjugated with the antibiotics during the synthesis of nanoparticles utilizing the combined reducing property of antibiotics and sodium borohydride. The conjugation of nanoparticles was confirmed by dynamic light scattering (DLS) and electron microscopic (EM) studies. Such Gnps conjugated antibiotics showed greater bactericidal activity in standard agar well diffusion assay. The minimal inhibitory concentration (MIC) values of all the three antibiotics along with their Gnps conjugated forms were determined in three bacterial strains,Escherichia coli DH5α,Micrococcus luteusandStaphylococcus aureus. Among them, streptomycin and kanamycin showed significant reduction in MIC values in their Gnps conjugated form whereas; Gnps conjugated ampicillin showed slight decrement in the MIC value compared to its free form. On the other hand, all of them showed more heat stability in their Gnps conjugated forms. Thus, our findings indicated that Gnps conjugated antibiotics are more efficient and might have significant therapeutic implications.
Industrial Home Laundry Closed Loop Cleaning Process
Authors: Scamehorn John F. , Tucker Edwin E. , Gecol Hatice , Komesvarakul Napaporn , Serventi Lorena K. , Raney Kirk H. , Capps Stephen F.
Published: November 2007

This study presents a method to develop an efficient and economical system for cleaning home laundry on a commercial scale with both water and chemical (detergent) reuse. The experiments were done using an industrial‐type horizontal‐axis machine, two leading consumer heavy‐duty liquid laundry detergents, one I&I detergent formulation, and chlorine bleach. The technical feasibility of reusing laundry water at high levels without significant deterioration in detergency was established in this study. Warm water (40 °C) was used in the wash cycle, and cold water (29 °C) was used for three rinse cycles. In the integrated process, waters from wash and rinse steps were treated using tubular microfiltration units with 0.1 μm pore size to remove particles and emulsion droplets. These recovered waters were recycled to be reused. In addition, water recycled from the wash step contains surfactants that can be reused. In order to simulate a large‐scale industrial laundry operation at steady‐state, the batch process used here was operated six times in sequence; wash and rinse waters were filtered after each cycle and reused in the next wash cycle. The surfactant recovery is over 40%. Soiled test strips were used to measure the percentage of soil removal after the wash/filtration sequence for stains and various liquid or particulate soils. The soil removal remained practically constant under simulated steady‐state conditions even with water recoveries of nearly 90%. Softness of towels remained unchanged when recycled water was used in this process. Chlorine carry‐over from white laundry to the wash process was shown to be minimal. This is important to avoid color fading in mixed loads upon reuse since water is not segregated for colored laundry versus white laundry. Hardness ions can precipitate fatty acids which reduce flux during filtration and decrease surfactant recovery. Preliminary analysis of the different formulations used indicates that an all‐nonionic formulation may be best suited to this recycling process.
Genistein and daidzein induced apoA-1 transactivation in hepG2 cells expressing oestrogen receptor-α
Authors: Yuen Yee M. , Leung Lai K.
Published: November 2007

Studies have shown that soya consumption has been associated with low incidence of CVD. Because the chemical structures of soya isoflavones are similar to oestrogen, the beneficial outcome may be attributed to the oestrogenicity of these compounds. In this study, effect of the soya isoflavone genistein on the mRNA expression of apoA-1 in the human hepatoma HepG2 cell was investigated. Without oestrogen receptor (ER) α transfection, soya isoflavones in the physiological range had no effect on the apoA-1 transcription. Once ERα was ectopically expressed in these cells, soya isoflavone dramatically increased the apoA-1 mRNA abundance quantified by real-time PCR.ApoA-1-reporter assays with plasmid constructed from the 5′-flanking segment upstream to the coding region revealed that the transactivation of theapoA-1promoter was induced by the soya isoflavone in HepG2 cells expressing ERα. This induction was reduced by the anti-oestrogen ICI 182780, but not the inhibitors of protein kinase (PK) C, PKA, or mitogen-activated PK. Based on the previously identified response elements on the promoter, a series of truncated promoter reporter plasmids were then constructed. An induction profile of genistein was built and insulin response core element at − 411 to − 404 appeared to be a potential site of interaction. This study illustrated that soya isoflavones at physiological concentrations could up regulate apoA-1 mRNA expression in ERα-transfected HepG2 cells.
Green tea catechin enhances cholesterol 7α-hydroxylase gene expression in HepG2 cells
Authors: Lee Mak-Soon , Park Ju-Yeon , Freake Hedley , Kwun In-Sook , Kim Yangha
Published: November 2007

Green tea catechins are known to have hypocholesterolaemic effects in animals and human subjects. In the present study, we investigated the effects of green tea catechins on the mRNA level and promoter activity of hepatic cholesterol 7α-hydroxylase (CYP7A1), the rate-limiting enzyme in the conversion of cholesterol to bile acids, in human hepatoma cells. Real-time PCR assays showed that different catechins, ( − )-epicatechin gallate (ECG), ( − )-epigallocatechin-3-gallate (EGCG), ( − )-epigallocatechin (EGC) and ( − )-epicatechin (EC), up regulated the CYP7A1 mRNA level by 5·5-, 4·2-, 2·9- and 1·9-fold, respectively, compared with the control. The − 1312/+358 bp of the CYP7A1 promoter was subcloned into the pGL3 basic vector that includes luciferase as a reporter gene. ECG or EGCG significantly increased CYP7A1 promoter activity by 6·0- or 4·0-fold, respectively, compared with the control. Also, EGCG stimulated CYP7A1 at both mRNA level and promoter activity in a dose-dependent manner. These results suggest that the expression of the CYP7A1 gene may be directly regulated by green tea catechins at the transcriptional level.
Temperature-related fitness costs of resistance to spinosad in the diamondback moth, Plutella xylostella (Lepidoptera: Plutelidae)
Authors: Li Z.M. , Liu S.S. , Liu Y.Q. , Ye G.Y.
Published: November 2007

Fitness costs associated with resistance genes expressed in the absence of insecticides affect the evolution of insecticide resistance and the outcome of resistance management programmes. However, measurements of fitness costs may not be straightforward as they vary with environmental conditions. The diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), has developed resistance to spinosad, the first insecticide of the Naturalyte class, after only a few years of field application of this product. In this study, we compared the performance of two homogenous strains of P. xylostella, one susceptible (SS) and the other resistant (RR) to spinosad at an unfavourable, low natural temperature regime, a favourable median-fluctuating temperature regime and an unfavourable high-fluctuating temperature regime. The RR strain showed only marginal fitness cost at the median temperature regime. At the low temperature regime, the RR strain failed to produce any viable offspring, while the SS strain achieved positive population growth. At the high temperature regime, the RR strain showed a 33% decrease in intrinsic rate of increase compared to the SS strain. The results demonstrate that fitness costs of resistance to spinosad are temperature-dependent, increasing in scale at unfavourably low and high temperatures; costs were particularly high at low temperatures. Suggestions for designing effective management programmes are made to delay or avoid development of resistance to spinosad by P. xylostella under different temperature conditions.
Randomized trial on the effectiveness of long-and short-term psychodynamic psychotherapy and solution-focused therapy on psychiatric symptoms during a 3-year follow-up
Authors: Knekt P. , Lindfors O. , Härkänen T. , Välikoski M. , Virtala E. , Laaksonen M. A. , Marttunen M. , Kaipainen M. , Renlund C. ,   the Helsinki Psychotherapy Study Group
Published: November 2007

Background

Insufficient evidence exists for a viable choice between long- and short-term psychotherapies in the treatment of psychiatric disorders. The present trial compares the effectiveness of one long-term therapy and two short-term therapies in the treatment of mood and anxiety disorders.

Method

In the Helsinki Psychotherapy Study, 326 out-patients with mood (84.7%) or anxiety disorder (43.6%) were randomly assigned to three treatment groups (long-term psychodynamic psychotherapy, short-term psychodynamic psychotherapy, and solution-focused therapy) and were followed up for 3 years from start of treatment. Primary outcome measures were depressive symptoms measured by self-report Beck Depression Inventory (BDI) and observer-rated Hamilton Depression Rating Scale (HAMD), and anxiety symptoms measured by self-report Symptom Check List Anxiety Scale (SCL-90-Anx) and observer-rated Hamilton Anxiety Rating Scale (HAMA).

Results

A statistically significant reduction of symptoms was noted for BDI (51%), HAMD (36%), SCL-90-Anx (41%) and HAMA (38%) during the 3-year follow-up. Short-term psychodynamic psychotherapy was more effective than long-term psychodynamic psychotherapy during the first year, showing 15–27% lower scores for the four outcome measures. During the second year of follow-up no significant differences were found between the short-term and long-term therapies, and after 3 years of follow-up long-term psychodynamic psychotherapy was more effective with 14–37% lower scores for the outcome variables. No statistically significant differences were found in the effectiveness of the short-term therapies.

Conclusions

Short-term therapies produce benefits more quickly than long-term psychodynamic psychotherapy but in the long run long-term psychodynamic psychotherapy is superior to short-term therapies. However, more research is needed to determine which patients should be given long-term psychotherapy for the treatment of mood or anxiety disorders.
A transdiagnostic investigation of ‘theory of mind’ and ‘jumping to conclusions’ in patients with persecutory delusions
Authors: Corcoran R. , Rowse G. , Moore R. , Blackwood N. , Kinderman P. , Howard R. , Cummins S. , Bentall R. P.
Published: November 2007

Background

A tendency to make hasty decisions on probabilistic reasoning tasks and a difficulty attributing mental states to others are key cognitive features of persecutory delusions (PDs) in the context of schizophrenia. This study examines whether these same psychological anomalies characterize PDs when they present in the context of psychotic depression.

Method

Performance on measures of probabilistic reasoning and theory of mind (ToM) was examined in five subgroups differing in diagnostic category and current illness status.

Results

The tendency to draw hasty decisions in probabilistic settings and poor ToM tested using story format feature in PDs irrespective of diagnosis. Furthermore, performance on the ToM story task correlated with the degree of distress caused by and preoccupation with the current PDs in the currently deluded groups. By contrast, performance on the non-verbal ToM task appears to be more sensitive to diagnosis, as patients with schizophrenia spectrum disorders perform worse on this task than those with depression irrespective of the presence of PDs.

Conclusions

The psychological anomalies associated with PDs examined here are transdiagnostic but different measures of ToM may be more or less sensitive to indices of severity of the PDs, diagnosis and trait- or state-related cognitive effects.
Source monitoring for actions in adolescents with 22q11.2 deletion syndrome (22q11DS)
Authors: Debbané M. , Van der Linden M. , Glaser B. , Eliez S.
Published: November 2007

Background

Source monitoring consists in identifying the origin of mental events. Recent research suggests that confusions over internally generated mental events may represent a cognitive marker for increased proneness to psychotic symptoms and disorders. We have examined source monitoring for actions in adolescents with the 22q11.2 deletion syndrome (22q11DS), a neurogenetic disease associated with high rates of schizophrenia during adulthood, and expected to observe source monitoring deficits in comparison to IQ-matched and typically developing controls.

Method

Eighteen adolescents with 22q11DS, 17 adolescents matched for age and IQ, and also 17 adolescents matched for age participated in this study. Our adapted action monitoring paradigm asked subjects to visualize a series of actions in three different conditions: (1) visualize themselves performing the action; (2) visualize the experimenter performing the action; or (3) simply repeat the action statements without visualization of the action performer.

Results

The adolescents with 22q11DS performed adequately in terms of recognition (hits), but in comparison to both control groups, they committed more source confusions on correctly recognized items. Further examination revealed that the adolescents were more likely to demonstrate confusions between exterior sources in which the self was not involved.

Conclusions

Source monitoring deficits can be observed in adolescents with 22q11DS, a syndrome putting them at high risk for developing schizophrenia. These deficits are discussed in terms of early cognitive processes associated with genetic risk for schizophrenia.
Isolation and spectral characterization of cadmium binding metallothionein
Authors: Park Hyun , Ahn In-Young , Choi Heeseon J. , Ji Jung Youn
Published: November 2007

A cadmium (Cd)-binding protein was isolated and characterized from the Antarctic clamLaternula ellipticaafter experimental exposure to a high concentration of Cd. Cd-binding metallothioneins (MTs) in the cytosol were purified using a procedure based on gel permeation and ion-exchange chromatography. The purified MTs were recognized by MT antibodies in a Western blotting assay. MALDI-TOF MS analyses showed that the molecular mass of the purified MTs was 7.27 kDa, which is typical of MTs found in marine invertebrates. The Cd binding to MT, reflected by the redistribution of Cd ions, was monitored by spectrophotometry. The absorption spectra profiles indicated the presence of Cd-MT complexes, and a 4 nm red shift of the unresolved lowest energy-absorption band occurred when five equivalents of Cd (II) were incorporated.
A NOTE ON THE POLICY IMPLICATIONS OF USING DIVISIA CONSUMPTION AND MONETARY AGGREGATES
Authors: DRAKE LEIGH , FLEISSIG ADRIAN R.
Published: November 2007

Using U.K. data that are consistent with utility maximizing behavior by consumers, we construct aggregates for both consumption goods (nondurables and services) and monetary assets that are consistent with economic aggregation theory. Using these aggregates and the stock of durable goods, we estimate the elasticities of substitution between various consumption goods and monetary assets. These estimates are compared to the corresponding results from conventional monetary and consumption aggregates. The results give important information for monetary policy and the monetary transmission mechanism. In particular, these substitution estimates provide insight into the recent changes in expenditure on durable goods. We also show that the use of conventional U.K. consumption and monetary aggregates often give incorrect estimates of substitution and can provide misleading policy insights.
Pension investments in employer stock
Authors: EVEN WILLIAM E. , MACPHERSON DAVID A.
Published: November 2007

This study examines the consequences of a pension fund investing in the stock of the sponsoring firm. Using a merger of data on pension asset holdings from IRS Form 5500 filings and financial data on the company's stock from CRSP, two broad questions are addressed: first, what factors influence the extent of a pension fund's investments in the employer's stock? Second, when a pension invests in the employer's stock, how much is lost as a result of poor diversification? The empirical results suggest that investments in employer stock are responsive to non-diversification costs, tax consequences, and the employee's ability to absorb risk. There is also evidence that employers and employees weight these factors differentially in their decision of how much employer stock to include in the pension. Using actual return data on pension plans, we also find that concentrated investments in employer stock substantially reduce risk-adjusted return performance. However, modest holdings of employer stock have negligible effects on pension performance.
Pension reductions: can welfare be preserved by delaying retirement?
Authors: LACHANCE MARIE-EVE
Published: November 2007

Economic and demographic pressures may lead Social Security systems and employers to reduce their pensions in the future. Can delaying retirement help preserve welfare in that context? We examine this question with a life-cycle framework which includes the utility from leisure. One unique feature of our model is that it lets the retirement date be endogenously determined, unless an external constraint or shock applies first. By solving this model we find that, in reasonable scenarios, working longer does little to mitigate the negative impact of pension reductions on welfare. Building on our model, we suggest strategies to enhance the effectiveness of policies designed to induce and enable longer working lives.
T Tauri stars: from mystery to magnetospheric accretion
Authors: Basri Gibor
Published: November 2007

This is a selective historical overview of the progess in understanding T Tauri spectra. Originally they were understood to be very young, but the physical conditions (or even geometry) of the material on the star and in its surroundings were mysterious. The origin and meaning of the emission lines was largely unknown. Today we have a detailed consensus of what is happening near and on these newly forming stars. They are very magnetically active, and the stellar field is strong and extensive enough to control both the final accretion onto the star and the launching of outflows which solve the angular momentum problem during formation. Much of this consensus has emerged from spectral information, but much remains to be learned. I highlight some of the seminal breakthroughs that have led to the current picture. There are very complex and time-variable components to the entire physical system that constitutes a T Tauri star, and spectral information at various wavelengths and resolutions is crucial to making further progress.
Magnetism, rotation and accretion in Herbig Ae-Be stars
Authors: Alecian E. , Wade G.A. , Catala C. , Folsom C. , Grunhut J. , Donati J.-F. , Petit P. , Bagnulo S. , Boehm T. , Bouret J.-C. , Landstreet J.D.
Published: November 2007

Studies of stellar magnetism at the pre-main sequence phase can provide important new insights into the detailed physics of the late stages of star formation, and into the observed properties of main sequence stars. This is especially true at intermediate stellar masses, where magnetic fields are strong and globally organised, and therefore most amenable to direct study. This talk reviews recent high-precision ESPaDOnS observations of pre-main sequence Herbig Ae-Be stars, which are yielding qualitatively new information about intermediate-mass stars: the origin and evolution of their magnetic fields, the role of magnetic fields in generating their spectroscopic activity and in mediating accretion in their late formative stages, and the factors influencing their rotational angular momentum.
The inner gaseous accretion disk around a Herbig Be star revealed by near- and mid-infrared spectro-interferometry
Authors: Kraus S. , Preibisch Th. , Ohnaka K.
Published: November 2007

Herbig Ae/Be stars are pre-main-sequence stars of intermediate mass, which are still accreting material from their environment, probably via a disk composed of gas and dust. Here we present a recent study of the geometry of the inner (AU-scale) circumstellar region around the Herbig Be star MWC 147 using long-baseline interferometry. By combining for the first time near- and mid-infrared spectro-interferometry on a Herbig star, our VLTI/AMBER and VLTI/MIDI data constrain not only the geometry of the brightness distribution, but also the radial temperature distribution in the disk. The emission from MWC 147 is clearly resolved and has a characteristic physical size of ∼1.3 AU and ∼9 AU at 2.2 μm and 11 μm respectively. This increase in apparent size towards longer wavelengths is much steeper than predicted by analytic disk models assuming power-law radial temperature distributions. For a detailed modeling of the interferometric data and the spectral energy distribution of MWC 147, we employ 2-D frequency-dependent radiation transfer simulations. This analysis shows that passive irradiated Keplerian dust disks can easily fit the SED, but predict much lower visibilities than observed, so these models can clearly be ruled out. Models of a Keplerian disk with emission from an optically thick inner gaseous accretion disk (inside the dust sublimation zone), however, yield a good fit of the SED and simultaneously reproduce the observed near- and mid-infrared visibilities. We conclude that the near-infrared continuum emission from MWC 147 is dominated by accretion luminosity emerging from an optically thick inner gaseous disk, while the mid-infrared emission also contains strong contributions from the passive irradiated dust disk.
An e-mail from Global Bukowina
Authors: Nelken David
Published: November 2007

This paper uses Teubner’s reinterpretation of Ehrlich’s idea of ‘living law’ in his paper on ‘Global Bukowina’ as a test case of what is involved in making a classical author speak to current issues. It argues that interpretation is a form of appropriation and that the process of re-contextualising ideas involves an unstable compromise between establishing what an author meant and what an author means.
Littoral blasts: Pumice‐water heat transfer and the conditions for steam explosions when pyroclastic flows enter the ocean
Authors: Dufek J. , Manga M. , Staedter M.
Published: November 2007

Steam explosions, or littoral blasts, generated when pyroclastic flows interact with seawater may be a common, although rarely documented, phenomena. The development of steam explosions rather than passive steam production is related to the rate of thermal energy transfer from hot pyroclasts to water. We conduct a series of laboratory experiments to quantify the heat transfer and steam production rates when hot pyroclasts encounter water. Hot pumice (>200°C) rapidly ingests water while remaining at the surface, producing measurable amounts of steam during the process. Approximately 10% of the thermal energy of the pumice particles is partitioned into the production of steam, and smaller particles have greater steam production rates. The laboratory experiments are used to develop a subgrid model for steam production that can be incorporated into a multiphase numerical framework. We use this model to study the critical steam production rates required to initiate explosive events. For conditions typical of many pyroclastic flows, particles smaller than ∼1–5 mm are required to initiate a littoral blast. A second set of two‐dimensional numerical simulations is conducted to simulate the 12–13 July Soufrière Hills dome collapse event that reached the sea. The simulations predict that the focus of the blast is likely generated several hundred meters offshore and although the landward directed base surge is primarily dry (<15% water vapor), the area immediately above the blast is steam‐rich and may be a likely site for the production of accretionary lapilli.
Mantle structure under Gibraltar constrained by dispersion of body waves
Authors: Bokelmann Götz , Maufroy Emeline
Published: November 2007

We study the Africa‐Iberia plate boundary in the vicinity of Gibraltar. Numerous models have been proposed for that region throughout the last decades, proposing mechanisms that range widely from continental delamination, convective removal, to subduction of oceanic lithosphere. To better constrain upper‐mantle structure under the region, we study waveforms of P‐waves that traverse the Alboran Sea region between Spain and Morocco. These show dispersive behavior, which, together with early arrival times, confirms the presence of an anomalous upper mantle structure under the Alboran Sea. The dispersion is consistent with that expected from subducted lithosphere. Waveforms of body waves therefore provide a way to better constrain the elusive mantle structure and dynamics of the Alboran Sea region.
Seven thousand year duration for a geomagnetic excursion constrained by 230Thxs
Authors: Knudsen Mads Faurschou , Henderson Gideon M. , Mac Niocaill Conall , West A. Joshua
Published: November 2007

The duration of geomagnetic excursions may provide important information about the geodynamo. It has proven difficult, however, to assess the exact duration of both excursions and reversals. We combine high‐resolution paleomagnetic records from marine sediments with measurements of the 230Thxs flux to the seafloor in order to better constrain the duration of the Iceland Basin Excursion (IBE). We find the duration of the IBE to be ∼7–8 kyr, implying that it is considerably longer than previous estimates for the Laschamp Excursion (∼2 kyr), and more similar in duration to that of full polarity reversals. There may not be, therefore, a characteristic timescale for transitional field configurations that distinguishes excursions from reversals.
Onset of Indian summer monsoon over Gadanki (13.5°N, 79.2°E): Study using lower atmospheric wind profiler
Authors: Jagannadha Rao V. V. M. , Roja Raman M. , Venkat Ratnam M. , Narayana Rao D. , Bhaskara Rao S. Vijaya
Published: November 2007

The onset of Indian summer monsoon (ISM) over Gadanki (13.5°N; 79.2°E) is identified using variations in signal‐to‐noise ratio (SNR), wind speed, wind direction and vertical velocity at 1.5 km (∼850 hPa) using lower atmospheric wind profiler (LAWP). Strengthening of the low level wind speed attaining 8 ms−1 with directional change from south‐easterlies to south‐westerlies defines the beginning of the monsoon. Enhancement in SNR few days before with noticeable magnitude of 5–10 dB at the time of onset combined with clear‐air vertical velocity reversal from downward to upward few days before onset and persisting during monsoon activity supplements the wind speed criteria in identifying onset. Hydrometeor velocity shows large downward values exceeding more than 1 ms−1 indicating occurrence of rainfall. It is proposed that UHF radar at a location can be used to identify the onset of ISM based on wind speed without considering rainfall separately.
Sea level anomalies control phytoplankton biomass in the Costa Rica Dome area
Authors: Kahru M. , Fiedler P. C. , Gille S. T. , Manzano M. , Mitchell B. G.
Published: November 2007

Satellite data show that chlorophyll‐a concentration (Chl‐a) in the northeastern tropical Pacific is well correlated with sea level anomaly (SLA). This correlation spans a wide spectrum of scales from large‐scale phenomena like ENSO to mesoscale cyclonic and anticyclonic eddies. Negative SLA (e.g. during La Niña events and in cyclonic eddies) is associated with the lifting of isopycnals in the nutricline and increased Chl‐a due to enhanced phytoplankton growth, while positive SLA (e.g. during El Niño events and in anticyclonic eddies) is associated with a deeper nutricline and reduced Chl‐a due to decreased phytoplankton growth. The coupling between SLA and Chl‐a anomaly in the Costa Rica Dome (CRD) area is tighter than has previously been recorded anywhere in the world ocean. 70% of the interannual variations in Chl‐a anomaly in the CRD area is explained by a combination of the positive and negative effects of SLA.
Failure patterns caused by localized rise in pore‐fluid overpressure and effective strength of rocks
Authors: Rozhko A. Y. , Podladchikov Y. Y. , Renard F.
Published: November 2007

In order to better understand the interaction between pore‐fluid overpressure and failure patterns in rocks we consider a porous elasto‐plastic medium in which a laterally localized overpressure line source is imposed at depth below the free surface. We solve numerically the fluid filtration equation coupled to the gravitational force balance and poro‐elasto‐plastic rheology equations. Systematic numerical simulations, varying initial stress, intrinsic material properties and geometry, show the existence of five distinct failure patterns caused by either shear banding or tensile fracturing. The value of the critical pore‐fluid overpressure pc at the onset of failure is derived from an analytical solution that is in excellent agreement with numerical simulations. Finally, we construct a phase‐diagram that predicts the domains of the different failure patterns and pc at the onset of failure.
Methods in the study of discrete upper hybrid waves
Authors: Yoon P. H. , Ye S. , LaBelle J. , Weatherwax A. T. , Menietti J. D.
Published: November 2007

Naturally occurring plasma waves characterized by fine frequency structure or discrete spectrum, detected by satellite, rocket‐borne instruments, or ground‐based receivers, can be interpreted as eigenmodes excited and trapped in field‐aligned density structures. This paper overviews various theoretical methods to study such phenomena for a one‐dimensional (1‐D) density structure. Among the various methods are parabolic approximation, eikonal matching, eigenfunction matching, and full numerical solution based upon shooting method. Various approaches are compared against the full numerical solution. Among the analytic methods it is found that the eigenfunction matching technique best approximates the actual numerical solution. The analysis is further extended to 2‐D geometry. A detailed comparative analysis between the eigenfunction matching and fully numerical methods is carried out for the 2‐D case. Although in general the two methods compare favorably, significant differences are also found such that for application to actual observations it is prudent to employ the fully numerical method. Application of the methods developed in the present paper to actual geophysical problems will be given in a companion paper.
Internal wave detection using the Moderate Resolution Imaging Spectroradiometer (MODIS)
Authors: Jackson Christopher
Published: November 2007

The Moderate Resolution Imaging Spectroradiometer (MODIS), with its combined attributes of fine spatial resolution, large swath area, and near‐daily global coverage, has for the first time allowed sunglint (the near‐specular reflectance pattern of sunlight off the ocean surface) to be used to analyze and survey high‐frequency nonlinear internal solitary wave occurrences on a near‐global scale. The sunglint area within the MODIS swath is large enough to cover an entire basin, and it's spatial resolution is fine enough to identify internal wave signatures whose wavelength is greater than a few hundred meters. This paper describes the use of MODIS for high‐frequency nonlinear internal wave detection, presents the results of a survey that detected 3581 internal wave occurrences in MODIS imagery over the period between August 2002 through May 2004, and discusses ways MODIS imagery can be used to improve the study of internal waves.
Signatures of large‐scale soil moisture dynamics on streamflow statistics across U.S. climate regimes
Authors: Botter G. , Peratoner F. , Porporato A. , Rodriguez‐Iturbe I. , Rinaldo A.
Published: November 2007

In this paper we address an observational validation of recent theoretical results on the structure of the probability density function (pdf) of daily streamflows through the analysis of data pertaining to several catchments covering various sizes, climatic regimes, and topographic features across the United States. Seasonal streamflow pdfs obtained from recorded time series are directly compared with the theoretical distribution derived by Botter et al. (2007a) by coupling a suitable transport model with a stochastic description of runoff production through soil moisture dynamics. The ecohydrological and morphological parameters defining the theoretical streamflow pdf are inferred for each watershed on the basis of easily gathered land use information and incorporate directly measured hydrologic and climatic data. An excellent agreement is shown with the corresponding observed distribution in variably sized and widely heterogeneous catchments across different climate regimes. In particular, our data confirm that the shape of the daily streamflow pdf shows different regimes well described by a Gamma distribution. Such regimes, roughly termed wet and dry, are controlled by the ratio between the runoff frequency and the inverse of the mean residence time of subsurface flow, which in turn controls the behavior of the basins for low‐stage streamflows.
Good news for CB1 receptors: endogenous agonists are in the right place
Authors: Maccarrone M
Published: November 2007

Endocannabinoids are endogenous ligands of brain‐type (CB1) and spleen‐type (CB2) cannabinoid receptors. N‐Arachidonoylethanolamine (anandamide, AEA) and 2‐arachidonoylglycerol (2‐AG) are prototype members of the fatty acid amides and the monoacylglycerols, two groups of endocannabinoids. Unlike CB1, CB2 receptors do not reside within ‘caveolae’, specialized membrane microdomains that are well‐known modulators of the activity of a number of G protein‐coupled receptors. In this issue of the British Journal of Pharmacology, Rimmerman and coworkers demonstrate that 2‐AG is entirely localized in the caveolae of dorsal root ganglion cells, where also part of AEA (∼30%) can be detected. However, most of AEA (∼70%) was detected in non‐caveolae fractions, that is where CB2 receptors are localized. The different interaction of AEA and 2‐AG with membrane microdomains might have significant implications for endocannabinoid‐dependent autocrine and/or retrograde‐paracrine signalling pathways. It also raises an important question about the structural determinants responsible for a different localization of two apparently similar endocannabinoids within lipid bilayers.

British Journal of Pharmacology (2008) 153, 179–181; doi:10.1038/sj.bjp.0707566; published online 12 November 2007
CB2 cannabinoid receptor agonists attenuate TNF‐α‐induced human vascular smooth muscle cell proliferation and migration
Authors: Rajesh M , Mukhopadhyay P , Haskó G , Huffman J W , Mackie K , Pacher P
Published: November 2007

Background and purpose:

Vascular smooth muscle proliferation and migration triggered by inflammatory stimuli are involved in the development and progression of atherosclerosis and restenosis. Cannabinoids may modulate cell proliferation in various cell types through cannabinoid 2 (CB2) receptors. Here, we investigated the effects of CB2 receptor agonists on TNF‐α‐induced proliferation, migration and signal transduction in human coronary artery smooth muscle cells (HCASMCs).

Experimental approach:

HCASMCs were stimulated with TNF‐α. Smooth muscle proliferation was determined by the extent of BrdU incorporation and the migration was assayed by modified Boyden chamber. CB2 and/or CB1 receptor expressions were determined by immunofluorescence staining, western blotting, RT‐PCR, real‐time PCR and flow cytometry.

Key results:

Low levels of CB2 and CB1 receptors were detectable in HCASMCs compared to the high levels of CB2 receptors expressed in THP‐1 monocytes. TNF‐α triggered up to ∼80% increase (depending on the method used) in CB2 receptor mRNA and/or protein expression in HCASMCs, and induced Ras, p38 MAPK, ERK 1/2, SAPK/JNK and Akt activation, while increasing proliferation and migration. The CB2 agonists, JWH‐133 and HU‐308, dose‐dependently attenuated these effects of TNF‐α.

Conclusions and implications:

Since the above‐mentioned TNF‐α‐induced phenotypic changes are critical in the initiation and progression of atherosclerosis and restenosis, our findings suggest that CB2 agonists may offer a novel approach in the treatment of these pathologies by decreasing vascular smooth muscle proliferation and migration.

British Journal of Pharmacology (2008) 153, 347–357; doi:10.1038/sj.bjp.0707569; published online 12 November 2007