bluuebunny/crossref_metadata_2025 huggingface dataset:
Collaborative care for depression in UK primary care: a randomized controlled trial
Authors: Richards D. A. , Lovell K. , Gilbody S. , Gask L. , Torgerson D. , Barkham M. , Bland M. , Bower P. , Lankshear A. J. , Simpson A. , Fletcher J. , Escott D. , Hennessy S. , Richardson R.
Published: September 2007

Background

Collaborative care is an effective intervention for depression which includes both organizational and patient-level intervention components. The effect in the UK is unknown, as is whether cluster- or patient-randomization would be the most appropriate design for a Phase III clinical trial.

Method

We undertook a Phase II patient-level randomized controlled trial in primary care, nested within a cluster-randomized trial. Depressed participants were randomized to ‘collaborative care’ – case manager-coordinated medication support and brief psychological treatment, enhanced specialist and GP communication – or a usual care control. The primary outcome was symptoms of depression (PHQ-9).

Results

We recruited 114 participants, 41 to the intervention group, 38 to the patient randomized control group and 35 to the cluster-randomized control group. For the intervention compared to the cluster control the PHQ-9 effect size was 0.63 (95% CI 0.18–1.07). There was evidence of substantial contamination between intervention and patient-randomized control participants with less difference between the intervention group and patient-randomized control group (−2.99, 95% CI −7.56 to 1.58, p=0.186) than between the intervention and cluster-randomized control group (−4.64, 95% CI −7.93 to −1.35, p=0.008). The intra-class correlation coefficient for our primary outcome was 0.06 (95% CI 0.00–0.32).

Conclusions

Collaborative care is a potentially powerful organizational intervention for improving depression treatment in UK primary care, the effect of which is probably partly mediated through the organizational aspects of the intervention. A large Phase III cluster-randomized trial is required to provide the most methodologically accurate test of these initial encouraging findings.
Co-morbidity and disorder-related distress and impairment in purging disorder
Authors: Keel P. K. , Wolfe B. E. , Gravener J. A. , Jimerson D. C.
Published: September 2007

Background

Recent studies suggest that purging disorder (PD) may be a common eating disorder that is associated with clinically significant levels of distress and high levels of psychiatric co-morbidity. However, no study has established evidence of disorder-related impairment or whether distress is specifically related to PD rather than to co-morbid disorders.

Method

Three groups of normal-weight women [non-eating disorder controls (n=38), with PD (n=24), and with bulimia nervosa (BN)-purging subtype (n=57)] completed structured clinical interviews and self-report assessments.

Results

Both PD and BN were associated with significant co-morbidity and elevations on indicators of distress and impairment compared to controls. Compared to BN, PD was associated with lower rates of current and lifetime mood disorders but higher rates of current anxiety disorders. Elevated distress and impairment were maintained in PD and BN after controlling for Axis I and Axis II disorders.

Conclusions

PD is associated with elevated distress and impairment and should be considered for inclusion as a provisional disorder in nosological schemes such as the Diagnostic and Statistical Manual to facilitate much-needed research on this clinically significant syndrome.
Effects of psychotherapy on regional cerebral blood flow during trauma imagery in patients with post-traumatic stress disorder: a randomized clinical trial
Authors: Lindauer R. J. L. , Booij J. , Habraken J. B. A. , van Meijel E. P. M. , Uylings H. B. M. , Olff M. , Carlier I. V. E. , den Heeten G. J. , van Eck-Smit B. L. F. , Gersons B. P. R.
Published: September 2007

Background

Functional brain-imaging studies in post-traumatic stress disorder (PTSD) have suggested functional alterations in temporal and prefrontal cortical regions. Effects of psychotherapy on these brain regions have not yet been examined.

Method

Twenty civilian PTSD out-patients and 15 traumatized control subjects were assessed at baseline using psychometric ratings. Cerebral blood flow was measured using trauma script-driven imagery during99mtechnetium hexamethyl-propylene-amine-oxime single-photon emission computed tomography scanning. All 20 out-patients were randomly assigned to treatment or wait-list conditions. Treatment was brief eclectic psychotherapy (BEP) in 16 weekly individual sessions.

Results

At baseline, greater activation was found in the right insula and right superior/middle frontal gyrus in the PTSD group than in the control group. PTSD patients treated with BEP significantly improved on all PTSD symptom clusters compared to those on the waiting list. After effective psychotherapy, lower activation was measured in the right middle frontal gyrus, compared to the PTSD patients on the waiting list. Treatment effects on PTSD symptoms correlated positively with activation in the left superior temporal gyrus, and superior/middle frontal gyrus.

Conclusions

BEP induced clinical recovery in PTSD patients, and appeared to modulate the functioning of specific PTSD-related sites in the prefrontal cortical regions.
MRI-based morphometry in children with multiple complex developmental disorder, a phenotypically defined subtype of pervasive developmental disorder not otherwise specified
Authors: Lahuis B. E. , Durston S. , Nederveen H. , Zeegers M. , Palmen S. J. M. C. , Van Engeland H.
Published: September 2007

Background

The DSM-IV-R classification Pervasive Developmental Disorder – Not otherwise Specified (PDD-NOS) is based on the symptoms for autism and includes a wide variety of phenotypes that do not meet full criteria for autism. As such, PDD-NOS is a broad and poorly defined residual category of the autism spectrum disorders. In order to address the heterogeneity in this residual category it may be helpful to define clinical and neurobiological subtypes. Multiple complex developmental disorder (MCDD) may constitute such a subtype. In order to study the neurobiological specificity of MCDD in comparison with other autism spectrum disorders, we investigated brain morphology in children (age 7–15 years) with MCDD compared to children with autism and typically developing controls.

Method

Structural MRI measures were compared between 22 high-functioning subjects with MCDD and 21 high-functioning subjects with autism, and 21 matched controls.

Results

Subjects with MCDD showed an enlarged cerebellum and a trend towards larger grey-matter volume compared to control subjects. Compared to subjects with autism, subjects with MCDD had smaller intracranial volume.

Conclusions

We report a pattern of volumetric changes in the brains of subjects with MCDD, similar to that seen in autism. However, no enlargement in head size was found. This suggests that although some of the neurobiological changes associated with MCDD overlap with those in autism, others do not. These neurobiological changes may reflect differences in the developmental trajectories associated with these two subtypes of autism spectrum disorders.
On the ergodicity of Weyl sum cocycles
Authors: GRESCHONIG GERNOT , NERURKAR MAHESH , VOLNÝ DALIBOR
Published: September 2007

We present the quadratic Weyl sums$\sum _{k=0}^{n-1} e^{2\pi i(k^2\theta +2kx)}$withθ,x∈[0,1) as cocycles over a measure-preserving transformation on the two-dimensional torus. We show then that these cocycles are not coboundaries for every irrationalθ∈[0,1), and that for a denseGδset ofθ∈[0,1) the corresponding skew product is ergodic. For each of thoseθ, there exists a denseGδset of full measure ofx∈[0,1) for which the sequence$\sum _{k=0}^{n-1} e^{2\pi i(k^2\theta +2kx)}$,n=1,2,… , is dense in$\mathbb {C}$.
KMS states and branched points
Authors: IZUMI MASAKI , KAJIWARA TSUYOSHI , WATATANI YASUO
Published: September 2007

We completely classify the Kubo–Martin–Schwinger (KMS) states for the gauge action on aC*-algebra associated with a rational functionRintroduced in our previous work. The gauge action has a phase transition atβ=log degR. We can recover the degree ofR, the number of branched points, the number of exceptional points and the orbits of exceptional points from the structure of the KMS states. We also classify the KMS states forC*-algebras associated with some self-similar sets, including the full tent map and the Sierpinski gasket by a similar method.
An example of how the Ricci flow can increase topological entropy
Authors: JANE DAN
Published: September 2007

We give a surface for which the Ricci flow applied to the metric will increase the topological entropy of the geodesic flow. Specifically, we first adapt the Melnikov method to apply to a Ricci flow perturbation and then we construct a surface which is closely related to a surface of revolution, but does not quite have rotational symmetry. This is done by adapting the Liouville metric representation of a surface of revolution. The final steps of the Melnikov method require numerical integration.
Measure rigidity for algebraic bipermutative cellular automata
Authors: SABLIK MATHIEU
Published: September 2007

Let $({\mathcal {A}^{\mathbb {Z}}} ,F)$ be a bipermutative algebraic cellular automaton. We present conditions that force a probability measure, which is invariant for the $ {\mathbb {N}} \times {\mathbb {Z}} $-action of F and the shift map σ, to be the Haar measure on Σ, a closed shift-invariant subgroup of the abelian compact group $ {\mathcal {A}^{\mathbb {Z}}} $. This generalizes simultaneously results of Host et al (B. Host, A. Maass and S. Martínez. Uniform Bernoulli measure in dynamics of permutative cellular automata with algebraic local rules. Discrete Contin. Dyn. Syst. 9(6) (2003), 1423–1446) and Pivato (M. Pivato. Invariant measures for bipermutative cellular automata. Discrete Contin. Dyn. Syst. 12(4) (2005), 723–736). This result is applied to give conditions which also force an (F,σ)-invariant probability measure to be the uniform Bernoulli measure when F is a particular invertible affine expansive cellular automaton on $ {\mathcal {A}^{\mathbb {N}}} $.
Algebraic methods in mechanism analysis and synthesis
Authors: Husty Manfred L. , Pfurner Martin , Schröcker Hans-Peter , Brunnthaler Katrin
Published: September 2007

Algebraic methods in connection with classical multidimensional geometry have proven to be very efficient in the computation of direct and inverse kinematics of mechanisms as well as the explanation of strange, pathological behavior. In this paper, we give an overview of the results achieved within the last few years using the algebraic geometric method, geometric preprocessing, and numerical analysis. We provide the mathematical and geometrical background, like Study's parametrization of the Euclidean motion group, the ideals belonging to mechanism constraints, and methods to solve polynomial equations. The methods are explained with different examples from mechanism analysis and synthesis.
Singular curves in the joint space and cusp points of 3-R

P

R parallel manipulators
Authors: Zein Mazen , Wenger Philippe , Chablat Damien
Published: September 2007

This paper investigates the singular curves in the joint space of a family of planar parallel manipulators. It focuses on special points, referred to as cusp points, which may appear on these curves. Cusp points play an important role in the kinematic behavior of parallel manipulators since they make possible a nonsingular change of assembly mode. The purpose of this study is twofold. First, it exposes a method to compute joint space singular curves of 3-RPR planar parallel manipulators. Second, it presents an algorithm for detecting and computing all cusp points in the joint space of these same manipulators.
A tribute to Joe Bilotta
Authors: DEMARCO PAUL , LEMERISE ELIZABETH
Published: September 2007

Dr. Joseph Bilotta, an eminent scientist in the field of fish visual
neurophysiology and psychophysics, died suddenly and unexpectedly on
January 2, 2006. A native of Niagara Falls, NY, Joe was born October 21,
1955. His passion for learning took him on a journey from an Associate
Degree in Mathematics in 1975 from Niagara County Community College to a
Ph.D. in Experimental Psychology conferred by the City University of New
York in 1987 under the mentorship of Dr. Israel Abramov. Joe continued his
training at Vanderbilt University, working as a post-doctoral fellow in
the laboratory of Dr. Maureen Powers. In 1991, Joe joined the faculty of
Western Kentucky University as an assistant professor of Psychology, and
quickly moved through the ranks, becoming full professor in 2001.
Variability in the firing of retinal ganglion cells of goldfish: A review
Authors: LEVINE MICHAEL W.
Published: September 2007

The isolated retina of the goldfish has proven a valuable resource for studying the variability of firing of retinal ganglion cells. Three major areas of study are considered here: the variability of maintained discharges, the correlated firing of neighboring ganglion cells, and the variability of responses to light. The sources of variability, its relationship to retinal processing, and its possible functional role in perception are examined through these three aspects of variability. The results are related to similar studies in mammals (mainly cats). This retrospective is biased toward my studies over 30 years.
Explaining the effect of a 1-year intervention promoting physical activity in middle schools: a mediation analysis
Authors: Haerens L , Cerin E , Maes L , Cardon G , Deforche B , De Bourdeaudhuij I
Published: September 2007

Objective

The aim of the present study was to examine the mediation effects of changes in psychosocial determinants of physical activity (attitude, social support, self-efficacy, perceived benefits and barriers) on changes in physical activity.

Design

One-year intervention study with baseline and 1-year post measures of physical activity habits and psychosocial correlates.

Setting

Fifteen middle schools.

Subjects

Boys and girls (n = 2840) aged 11–15 years completed the validated questionnaires during class hours.

Results

The product-of-coefficients test was used to asses the mediating effects. Self-efficacy for physical activity at school was found to be the only significant mediator of physical activity change. Specifically, self-efficacy for physical activity at school partly mediated the effect of the intervention on total and school-related physical activity change in the intervention group with parental support (P < 0.05). None of the other potential mediators, attitudes, social support, perceived benefits and perceived barriers, seemed to have had a positive effect. Even a suppressor effect was found for attitudes. Given that the effects of self-efficacy and attitudes were of opposite direction, the total mediated/suppressed effects of the intervention were not statistically significant.

Conclusions

Positive changes in total and school-related physical activity in adolescents could be partly explained by increases in self-efficacy for physical activity at school through a physical activity intervention in middle schools with parental support. However, the suppressor effect of attitudes decreased this effect. As this is one of the first true mediation analyses in this age group, further research is needed to replicate the importance of these mediators.
Voices silenced, voices rediscovered: victims of violence and the reclamation of language in transitional societies
Authors: Simpson Kirk
Published: September 2007

In this article, I argue that the reclamation of language and the rediscovery of victims’ voices in post-conflict contexts are vital to the realisation of full human rights for all citizens, and necessary preludes to processes of truth recovery. Allowing and encouraging victims to engage in dialogue and public storytelling constitutes a crucial part of the transitional legal and political process. However, as a consequence of campaigns of political murder, torture and detention by oppressive regimes many victims of violence have been returned to a ‘pre-language’ state, in which the articulation of coherent individual and group histories has become increasingly difficult. I contend that enabling victims to reclaim language and narrate their stories is a crucial aspect of the legal, social and political ‘rebalancing project’ necessary in transitional societies to right the wrongs of the past.
Source apportionment of PM2.5 organic aerosol over Europe: Primary/secondary, natural/anthropogenic, and fossil/biogenic origin
Authors: Gelencsér András , May Barbara , Simpson David , Sánchez‐Ochoa Asunción , Kasper‐Giebl Anne , Puxbaum Hans , Caseiro Alexandre , Pio Casimiro , Legrand Michel
Published: September 2007

On the basis of a 2‐year comprehensive data set obtained within the CARBOSOL project, seasonal source apportionment of PM2.5 aerosol is attempted for five rural/remote sites in Europe. The approach developed combines radiocarbon measurements with bulk measurements of organic carbon (OC), elemental carbon (EC), and two organic tracers (levoglucosan and cellulose). Source types are lumped into primary emissions from fossil fuel combustion and biomass burning, bioaerosol, and secondary organic aerosol from precursors emitted by fossil and nonfossil sources. Bulk concentration ratios reported for these source types in the literature are used to estimate the source contributions which are constrained by measured radiocarbon concentrations. It has been found that while fossil‐related sources predominate EC throughout the year at all sites, the sources of OC are primarily biogenic and markedly different between summer and winter. In winter biomass burning primary emission is the main source, with sizable additional contribution from fossil fuel combustion. In contrast, in summer secondary organic aerosol (SOA) from nonfossil sources becomes predominant (63–76% of TC), with some contribution of SOA from fossil fuel combustion. The results agree well with recent findings of other authors who established the predominance of biogenic SOA for rural sites in summer in Europe. An uncertainty analysis has been conducted, which shows that the main conclusions from this study are robust.
A cloud‐resolving modeling study of a torrential rainfall event over China
Authors: Xu Xiaofeng , Xu Fengwen , Li Bai
Published: September 2007

A torrential rainfall event that occurred in Hunan, China in June 2004 is investigated using a two‐dimensional cloud‐resolving simulation. The model is integrated for 6 days with imposed zonally uniform vertical velocity, zonal wind, horizontal temperature, and vapor advection from National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis data. The comparison in surface rain rate and reflectivity between the simulations and observations shows good agreement. The simulation data during the torrential rainfall event (a 37‐hour period) are further analyzed to explore the physical causes in the surface rainfall processes. The time‐ and domain‐mean analysis shows that although their rates in the onset and mature stages are similar, vapor convergence mainly supports local vapor gain in the onset stage and surface rainfall in the mature stage. As a result, the surface rain rate is significantly smaller in the onset stage than in the mature stage. The weakening of vapor convergence finally suppresses the surface rainfall during the decay stage.
Numerical modeling and field evidence of coastal overwash in southern New England from Hurricane Bob and implications for paleotempestology
Authors: Cheung Kwok Fai , Tang Liujuan , Donnelly Jeffrey P. , Scileppi Elyse M. , Liu Kam‐Biu , Mao Xian‐Zhong , Houston Samuel H. , Murnane Richard J.
Published: September 2007

In this paper, we examine the use of coastal overwash modeling in conjunction with geological proxy techniques to provide a more comprehensive tool for paleotempestology. Southern New England, which lies in the path of north tracking hurricanes, has been a prime location for paleotempestological studies. Hurricane Bob of 1991 is the most recent landfall in this region and has the most comprehensive data for model assessment and validation. Using the hurricane track, central pressure, and radius of maximum wind as input, a collection of four interoperable model components simulates the meteorological conditions, astronomical tides and storm surge, ocean and coastal waves, and the surf zone processes and runup onto dry land. The computed surface pressure, winds, waves, and water levels give very good agreement with data from weather stations, moored buoys, and tide gauges near the track and in the zone of maximum wind. The validated wave conditions and storm water levels define the boundary conditions for coastal overwash modeling, and the results show strong correlation with aerial photographs and sedimentary records at five sites near the landfall. The results provide modern analogs for the interpretation of early hurricane landfalls in southern New England that lack an instrumental record. Reconstruction of paleohurricanes will require geological proxy data at multiple locations for the multivariate inverse analysis with uncertain paleotopography and storm characteristics.
Subcritical water extraction of amino acids from Atacama Desert soils
Authors: Amashukeli Xenia , Pelletier Christine C. , Kirby James P. , Grunthaner Frank J.
Published: September 2007

Amino acids are considered organic molecular indicators in the search for extant and extinct life in the Solar System. Extraction of these molecules from a particulate solid matrix, such as Martian regolith, will be critical to their in situ detection and analysis. The goals of this study were to optimize a laboratory amino acid extraction protocol by quantitatively measuring the yields of extracted amino acids as a function of liquid water temperature and sample extraction time and to compare the results to the standard HCl vapor‐phase hydrolysis yields for the same soil samples. Soil samples from the Yungay region of the Atacama Desert (Martian regolith analog) were collected during a field study in the summer of 2005. The amino acids (alanine, aspartic acid, glutamic acid, glycine, serine, and valine) chosen for analysis were present in the samples at concentrations of 1–70 parts‐per‐billion. Subcritical water extraction efficiency was examined over the temperature range of 30–325 °C, at pressures of 17.2 or 20.0 MPa, and for water‐sample contact equilibration times of 0–30 min. None of the amino acids were extracted in detectable amounts at 30 °C (at 17.2 MPa), suggesting that amino acids are too strongly bound by the soil matrix to be extracted at such a low temperature. Between 150 °C and 250 °C (at 17.2 MPa), the extraction efficiencies of glycine, alanine, and valine were observed to increase with increasing water temperature, consistent with higher solubility at higher temperatures, perhaps due to the decreasing dielectric constant of water. Amino acids were not detected in extracts collected at 325 °C (at 20.0 MPa), probably due to amino acid decomposition at this temperature. The optimal subcritical water extraction conditions for these amino acids from Atacama Desert soils were achieved at 200 °C, 17.2 MPa, and a water‐sample contact equilibration time of 10 min.
Area and width functions of river networks: New results on multifractal properties
Authors: Lashermes Bruno , Foufoula‐Georgiou Efi
Published: September 2007

This paper investigates the multiscale statistical structure of the area and width functions of simulated and real river networks via state‐of‐the‐art wavelet‐based multifractal (MF) formalisms. First, several intricacies in performing MF analysis of these signals are discussed, and a robust framework for accurate estimation of the MF spectrum is presented. Second, it considers the following three questions: (1) Does the topology of river networks leave a unique signature on the MF spectrum of area and width functions? (2) How different are the MF properties of commonly used simulated trees and those of real river networks? and (3) Are there differences between the MF properties of width and area functions, and what can these tell us about the topology of hillslope versus channelized drainage patterns in a river basin? The results indicate discrepancies between the statistical scaling of the area functions of real networks (found to be multifractal with a considerable spread of local singularities and the most prevailing singularity ranging from 0.4 to 0.8) and that of several commonly used stochastic self‐similar networks (found to be monofractal with a single singularity exponent H in the range of 0.5–0.65). Moreover, differences are found between the MF properties of width and area functions of the same basin. These differences may be the result of distinctly different branching topologies in the hillslope versus channelized drainage paths and need to be further investigated.
Breakthrough curve tailing in a dipole flow field
Authors: Luo Jian , Dentz Marco , Cirpka Olaf A. , Kitanidis Peter K.
Published: September 2007

Studying the tailing behavior of breakthrough curves (BTCs) is useful in the characterization of anomalous transport, matrix diffusion, and kinetic sorption. We analyze how BTCs of nonreactive and sorbing tracers behave at late time in well‐to‐well flow fields in homogeneous media. In the absence of regional flow, an asymptotic solution is derived for the traveltime distribution which follows a power law with exponent −4/3 at late times. With regional flow, the traveltime distribution exhibits a power law with exponent −4/3 over a certain period of time, followed by exponential decay. Dispersion influences the early time behavior but has little effect on the late‐time tailing. We also consider the BTC tailing of tracers undergoing kinetic sorption and diffusive mass transfer into immobile regions. If the memory function characterizing sorption kinetics is exponential, the late‐time behavior of the BTC is controlled by the traveltime distribution and thus follows a power law with exponent −4/3. In case of a matrix diffusion model, the memory function exhibits a power law with exponent −1/2, and the BTC in the dipole flow field follows a power law with exponent −7/6 in an intermediate time range, which differs from the exponent of −3/2 observed in uniform flow. Our analysis demonstrates that the flow configuration has to be considered when the tailing behavior of BTCs is used to characterize mass transfer kinetics. In particular, truncating a well‐to‐well tracer test at times where the traveltime distribution still follows the power law behavior may lead to the erroneous interpretation that the power law tailing of the BTC is caused by matrix diffusion.
Long‐term water chemistry database, Little River Experimental Watershed, southeast Coastal Plain, United States
Authors: Feyereisen G. W. , Lowrance R. , Strickland T. C. , Sheridan J. M. , Hubbard R. K. , Bosch D. D.
Published: September 2007

A water quality sampling program was initiated in 1974 by the U.S. Department of Agriculture Agricultural Research Service on the 334 km2 Little River Experimental Watershed (LREW) near Tifton in south Georgia to monitor the effects of changing land use and agricultural practices over time and to support development of simulation models capable of predicting future impacts of agricultural land use and management changes. Stream samples were taken on a weekly or more frequent basis and were analyzed for chloride, ammonium nitrogen, nitrate plus nitrite nitrogen, total kjeldahl nitrogen, total phosphorus, and dissolved molybdate reactive phosphorus. Monitoring began in 1974 on the entire watershed and four nested subwatersheds, ranging in size from 16.7 to 114.9 km2, and continues until present. Partial records of 7, 10, and 19 years exist for three additional subwatersheds. Suspended solids data are available for all eight subwatersheds for 1974–1978 and 1979–1981, three subwatersheds for 1982–1986, and all eight subwatersheds again beginning in the year 2000. The concentration and associated load data are being published on the LREW database anonymous ftp site (ftp://www.tiftonars.org/).
A bound on heat flow below a double crossing of the perovskite‐postperovskite phase transition
Authors: Buffett Bruce A.
Published: September 2007

A double crossing of the perovskite‐postperovskite phase transition in (Mg,Fe)SiO3 has been proposed to explain seismic reflections from structures near the base of the mantle. Estimates of temperature inferred from the phase transitions can be extrapolated to the core‐mantle boundary (CMB) using a simple model for the thermal boundary layer. However, a complication arises when flow is driven by the (negative) buoyancy of the postperovskite phase. Latent heat release and advective transport increase the temperature gradient and heat flow below the region of postperovskite. A minimum bound on the temperature gradient at the CMB is obtained by noting that the temperature gradient at the base of the postperovskite region must be at least as steep as the transition temperature with depth. Both the temperature and heat flow at the CMB depend on the vertical velocity at the phase transition. A representative velocity of 1 mm/yr gives a local heat flux of 160 m W m−2. Increasing the velocity by a factor of two yields a substantially higher heat flow and an unreasonably hot temperature at the top of the core.
Whole mantle discontinuity structure beneath Hawaii
Authors: Courtier Anna M. , Bagley Brian , Revenaugh Justin
Published: September 2007

We examined mantle structure beneath the southeast Hawaiian Islands using multiple ScS reverberations from four earthquakes from the island of Hawaii and recorded at station KIP on the island of Oahu. We find an unusually deep 410‐km discontinuity and a transition zone thickness of 227 km, corresponding to a temperature increase of 87 K above the global average. Other reflectors include a lid‐low‐velocity zone boundary, a weak 520‐km discontinuity, and smaller discontinuities at 224 km, 288 km, and 1000 km. Whole mantle travel time is near the global average, which we attribute to an inclined or branching plume, lowermost mantle anisotropy, and estimate bias due to a possible ultra‐low velocity zone atop the core.
Design of a light‐oil piezomanometer for measurement of hydraulic head differences and collection of groundwater samples
Authors: Kennedy Casey D. , Genereux David P. , Corbett D. Reide , Mitasova Helena
Published: September 2007

This paper describes a device (“piezomanometer”) that combines three components (an oil‐water manometer, a pushable screened PVC probe, and a system for groundwater sample collection) into a single inexpensive ($130), easily built, reliable tool for rapid collection of shallow groundwater from a streambed or lake bed and accurate measurement of even very small head differences between this groundwater and overlying surface water. The piezomanometer has been tested with excellent results both in the lab and in a stream shallow enough for wading; in principle, it could be adapted for use in deeper water where work is done from a dock, boat, or other platform. The problem of gas bubbles collecting in the groundwater line (a common drawback of field manometers) was nearly eliminated by use of a three‐way valve at a local elevation maximum in the groundwater line (gas bubbles in the groundwater line can be purged through this valve). Field application is illustrated here with data from a 2‐day study using four piezomanometers in a North Carolina stream.
Effects of ciprofloxacin on salt marsh sediment microbial communities
Authors: Córdova-Kreylos Ana Lucía , Scow Kate M
Published: September 2007

Fluoroquinolones, a widely used class of antibiotics, are frequently detected in sediments and surface waters. Given their antimicrobial properties, the presence of these compounds may alter the composition of microbial communities and promote antibiotic resistance in the environment. The purpose of this study was to measure sorption, and effects of ciprofloxacin on microbial community composition, in sediment samples from three California salt marshes. Sediments were exposed to a ciprofloxacin concentration gradient (0–200 μg ml−1 ciprofloxacin) and microbial community composition characterized using phospholipid fatty acid (PLFA) analysis. Sorption coefficients, expressed as log Kd, were calculated from fits using the Freundlich isotherm model. Ciprofloxacin strongly sorbed to all sediments and had log Kd values, ranging from 2.9 to 4.3. Clay content was positively (r2=0.98) and pH negatively (r2=0.99) correlated to Kd values. Biomass, PLFA richness, sulfate reducer and Gram-negative bacteria markers increased with ciprofloxacin concentrations, while the 17 cy/precursor and saturated/unsaturated biomarker ratios, indicators of starvation stress, decreased. The magnitude of the effect of ciprofloxacin on microbial communities was inversely correlated to the degree of sorption to the sediments. Despite the fact that ciprofloxacin is a wide-spectrum antibiotic, its impact on sediment microbial communities was selective and appeared to favor sulfate-reducing bacteria and Gram-negative bacteria.
Supraspinal modulation of pain by cannabinoids: the role of GABA and glutamate
Authors: Rea K , Roche M , Finn D P
Published: September 2007

Recent physiological, pharmacological and anatomical studies provide evidence that one of the main roles of the endocannabinoid system in the brain is the regulation of γ‐aminobutyric acid (GABA) and glutamate release. This article aims to review this evidence in the context of its implications for pain. We first provide a brief overview of supraspinal regulation of nociception, followed by a review of the evidence that the brain's endocannabinoid system modulates nociception. We look in detail at regulation of supraspinal GABAergic and glutamatergic neurons by the endocannabinoid system and by exogenously administered cannabinoids. Finally, we review the evidence that cannabinoid‐mediated modulation of pain involves modulation of GABAergic and glutamatergic neurotransmission in key brain regions.

British Journal of Pharmacology(2007)152, 633–648; doi:10.1038/sj.bjp.0707440; published online 10 September 2007
Alzheimer's disease; taking the edge off with cannabinoids?
Authors: Campbell V A , Gowran A
Published: September 2007

Alzheimer's disease is an age‐related neurodegenerative condition associated with cognitive decline. The pathological hallmarks of the disease are the deposition of β‐amyloid protein and hyperphosphorylation of tau, which evoke neuronal cell death and impair inter‐neuronal communication. The disease is also associated with neuroinflammation, excitotoxicity and oxidative stress. In recent years the proclivity of cannabinoids to exert a neuroprotective influence has received substantial interest as a means to mitigate the symptoms of neurodegenerative conditions. In brains obtained from Alzheimer's patients alterations in components of the cannabinoid system have been reported, suggesting that the cannabinoid system either contributes to, or is altered by, the pathophysiology of the disease. Certain cannabinoids can protect neurons from the deleterious effects of β‐amyloid and are capable of reducing tau phosphorylation. The propensity of cannabinoids to reduce β‐amyloid‐evoked oxidative stress and neurodegeneration, whilst stimulating neurotrophin expression neurogenesis, are interesting properties that may be beneficial in the treatment of Alzheimer's disease. Δ9‐tetrahydrocannabinol can also inhibit acetylcholinesterase activity and limit amyloidogenesis which may improve cholinergic transmission and delay disease progression. Targeting cannabinoid receptors on microglia may reduce the neuroinflammation that is a feature of Alzheimer's disease, without causing psychoactive effects. Thus, cannabinoids offer a multi‐faceted approach for the treatment of Alzheimer's disease by providing neuroprotection and reducing neuroinflammation, whilst simultaneously supporting the brain's intrinsic repair mechanisms by augmenting neurotrophin expression and enhancing neurogenesis. The evidence supporting a potential role for the cannabinoid system as a therapeutic target for the treatment of Alzheimer's disease will be reviewed herewith.

British Journal of Pharmacology (2007) 152, 655–662; doi:10.1038/sj.bjp.0707446; published online 10 September 2007
Δ9‐Tetrahydrocannabinol inhibits electrically‐evoked CGRP release and capsaicin‐sensitive sensory neurogenic vasodilatation in the rat mesenteric arterial bed
Authors: Wilkinson J D , Kendall D A , Ralevic V
Published: September 2007

Background and purpose:

Calcitonin gene‐related peptide (CGRP) is a sensory neurotransmitter in the rat mesenteric arterial bed. Certain cannabinoids can inhibit, via CB1 receptors, vasorelaxant responses to electrical field stimulation (EFS) of sensory nerves in the rat mesentery, but the mechanism of the inhibitory effect of the cannabinoid Δ9‐tetrahydrocannabinol (THC) is unclear. This study assessed directly the effect of THC on EFS‐induced release of CGRP from sensory nerves in the rat mesenteric bed and investigated the possible involvement of cannabinoid receptors and transient receptor potential (TRP) ion channels.

Experimental approach:

Rat mesenteric beds were perfused with physiological salt solution. Sensory nerves were stimulated electrically and perfusate levels of CGRP measured by immunoassay. The effects of THC on EFS‐induced CGRP release and vasorelaxant responses to sensory nerve stimulation were investigated in the absence and presence of cannabinoid antagonists and TRP channel blockers.

Key results:

EFS evoked a release of CGRP and vasodilatation of the mesenteric beds. THC inhibited the electrically‐evoked release of CGRP and sensory neurogenic vasorelaxation. The effect of THC was unaffected by the CB1 antagonist AM251, the CB2 antagonist AM630 or the TRPV1 receptor antagonist capsazepine, but was blocked by the TRP channel blocker ruthenium red.

Conclusions and implications:

THC inhibits the EFS‐induced release of CGRP (and subsequent vasorelaxation), from capsaicin‐sensitive sensory nerves in the rat perfused mesentery. The effect of THC was not mediated by CB1, CB2 or TRPV1 receptors, but was sensitive to ruthenium red, suggesting a possible involvement of TRP ion channels.

British Journal of Pharmacology (2007) 152, 709–716; doi:10.1038/sj.bjp.0707448; published online 10 September 2007
Reduced inhibition of cortical glutamate and GABA release by halothane in mice lacking the K+ channel, TREK‐1
Authors: Westphalen R I , Krivitski M , Amarosa A , Guy N , Hemmings H C
Published: September 2007

Background and purpose:

Deletion of TREK‐1, a two‐pore domain K+ channel (K2P) activated by volatile anaesthetics, reduces volatile anaesthetic potency in mice, consistent with a role for TREK‐1 as an anaesthetic target. We used TREK‐1 knockout mice to examine the presynaptic function of TREK‐1 in transmitter release and its role in the selective inhibition of glutamate vs GABA release by volatile anaesthetics.

Experimental approach:

The effects of halothane on 4‐aminopyridine‐evoked and basal [3H]glutamate and [14C]GABA release from cerebrocortical nerve terminals isolated from TREK‐1 knockout (KO) and littermate wild‐type (WT) mice were compared. TREK‐1 was quantified by immunoblotting of nerve terminal preparations.

Key results:

Deletion of TREK‐1 significantly reduced the potency of halothane inhibition of 4‐aminopyridine‐evoked release of both glutamate and GABA without affecting control evoked release or the selective inhibition of glutamate vs GABA release. TREK‐1 deletion also reduced halothane inhibition of basal glutamate release, but did not affect basal GABA release.

Conclusions and implications:

The reduced sensitivity of glutamate and GABA release to inhibition by halothane in TREK‐1 KO nerve terminals correlates with the reduced anaesthetic potency of halothane in TREK‐1 KO mice observed in vivo. A presynaptic role for TREK‐1 was supported by the enrichment of TREK‐1 in isolated nerve terminals determined by immunoblotting. This study represents the first evidence for a link between an anaesthetic‐sensitive 2‐pore domain K+ channel and presynaptic function, and provides further support for presynaptic mechanisms in determining volatile anaesthetic action.

British Journal of Pharmacology (2007) 152, 939–945; doi:10.1038/sj.bjp.0707450; published online 10 September 2007
Effect of matrix on IR frequencies of acetylene and acetylene-methanol complex: Infrared matrix isolation and ab initio study
Authors: Jovan Jose K. V. , Gadre Shridhar R. , Sundararajan K. , Viswanathan K. S.
Published: September 2007

Effect of nitrogen and argon matrices on the C–H asymmetric stretching and bending infrared frequencies of the acetylene molecule, C2H2, has been studied by matrix isolation experiments as well as by calculations at MP2 level of theory. The complexes of C2H2 in nitrogen and argon matrices, viz., C2H2(N2)m (with m=2–8) and C2H2(Ar)n (with n=2–10) are theoretically explored. The computed acetylenic C–H asymmetric stretch in C2H2-nitrogen complexes shows a redshift of 3.0 to 11.9 cm−1 compared with the frequencies of the free acetylene molecule, and a corresponding blueshift of 7.4 to 26.2 cm−1 when C2H2 is complexed with argon atoms. The trends in the computed shifts are in good agreement with the experiments. The molecular electrostatic potential minimum of C2H2 becomes more negative when complexed with nitrogen than on complexation with argon. This observation implies a greater basic character for C2H2 in the nitrogen matrix, favoring the formation of H–π(C2H2–MeOH) complex as compared to that in the Ar matrix. Experimentally the preferential formation of H–π(C2H2-MeOH) complex in the N2 matrix has indeed been observed.
Response to “Comment on ‘Power loss in open cavity diodes and a modified Child-Langmuir law' ” [Phys. Plasmas 14, 094701 (2007)]
Authors: Biswas Debabrata , Kumar Raghwendra , Puri R. R.
Published: September 2007

It is shown in this response that the radiated power from an intense beam of accelerating electrons can be a sizable fraction of the total injected power. Further, it is argued that the association of an effective electrostatic potential with the real voltage drop across an open diode can either lead to the unphysical consequence that accelerated electrons do not radiate or to the unreal situation in which the diode must be considered closed. Rather, it is shown that in the real scenario, the entire energy (or applied potential) is fed to the diode region, one part of which results in energy gain of the electrons and another that leaks out as radiated energy from the opening in the diode region.
Two classes of quasi-steady-state model reductions for stochastic kinetics
Authors: Mastny Ethan A. , Haseltine Eric L. , Rawlings James B.
Published: September 2007

The quasi-steady-state approximation (QSSA) is a model reduction technique used to remove highly reactive species from deterministic models of reaction mechanisms. In many reaction networks the highly reactive intermediates (QSSA species) have populations small enough to require a stochastic representation. In this work we apply singular perturbation analysis to remove the QSSA species from the chemical master equation for two classes of problems. The first class occurs in reaction networks where all the species have small populations and the QSSA species sample zero the majority of the time. The perturbation analysis provides a reduced master equation in which the highly reactive species can sample only zero, and are effectively removed from the model. The reduced master equation can be sampled with the Gillespie algorithm. This first stochastic QSSA reduction is applied to several example reaction mechanisms (including Michaelis-Menten kinetics) [Biochem. Z. 49, 333 (1913)]. A general framework for applying the first QSSA reduction technique to new reaction mechanisms is derived. The second class of QSSA model reductions is derived for reaction networks where non-QSSA species have large populations and QSSA species numbers are small and stochastic. We derive this second QSSA reduction from a combination of singular perturbation analysis and the Ω expansion. In some cases the reduced mechanisms and reaction rates from these two stochastic QSSA models and the classical deterministic QSSA reduction are equivalent; however, this is not usually the case.
Molecular dynamics simulation of premelting and melting phase transitions in stoichiometric uranium dioxide
Authors: Yakub Eugene , Ronchi Claudio , Staicu Dragos
Published: September 2007

Results of molecular dynamics (MD) simulation of UO2 in a wide temperature range are presented and discussed. A new approach to the calibration of a partly ionic Busing-Ida-type model is proposed. A potential parameter set is obtained reproducing the experimental density of solid UO2 in a wide range of temperatures. A conventional simulation of the high-temperature stoichiometric UO2 on large MD cells, based on a novel fast method of computation of Coulomb forces, reveals characteristic features of a premelting λ transition at a temperature near to that experimentally observed (Tλ=2670K). A strong deviation from the Arrhenius behavior of the oxygen self-diffusion coefficient was found in the vicinity of the transition point. Predictions for liquid UO2, based on the same potential parameter set, are in good agreement with existing experimental data and theoretical calculations.
Ab initio calculations on low-lying electronic states of SbO2− and Franck-Condon simulation of its photodetachment spectrum
Authors: Lee Edmond P. F. , Dyke John M. , Mok Daniel K. W. , Chau Foo-tim , Chow Wan-ki
Published: September 2007

Geometry optimization and harmonic vibrational frequency calculations have been carried out on the low-lying singlet and triplet electronic states of the antimony dioxide anion (SbO2−) employing a variety of ab initio methods. Both large-core and small-core relativistic effective core potentials were used for Sb in these calculations, together with valence basis sets of up to augmented correlation-consistent polarized-valence quintuple-zeta (aug-cc-pV5Z) quality. The ground electronic state of SbO2− is determined to be the X̃A11 state, with the ãB13 state, calculated to be ∼48kcalmole−1 (2.1eV) higher in energy. Further calculations were performed on the X̃A12, ÃB22, and B̃A22 states of SbO2 with the aim to simulating the photodetachment spectrum of SbO2−. Potential energy functions (PEFs) of the X̃A11 state of SbO2− and the X̃A12, ÃB22, and B̃A22 states of SbO2 were computed at the complete-active-space self-consistent-field multireference internally contracted configuration interaction level with basis sets of augmented correlation-consistent polarized valence quadruple-zeta quality. Anharmonic vibrational wave functions obtained from these PEFs were used to compute Franck-Condon factors between the X̃A11 state of SbO2− and the X̃A12, ÃB22, and B̃A22 states of SbO2, which were then used to simulate the photodetachment spectrum of SbO2−, which is yet to be recorded experimentally.