bluuebunny/crossref_metadata_2025 huggingface dataset:
Vestibulosympathetic reflex during the early follicular and midluteal phases of the menstrual cycle
Authors: Lawrence Johnathan E. , Ray Chester A. , Carter Jason R.
Published: April 2008

Evidence suggests that both the arterial baroreflex and vestibulosympathetic reflex contribute to blood pressure regulation, and both autonomic reflexes integrate centrally in the medulla cardiovascular center. A previous report indicated increased sympathetic baroreflex sensitivity during the midluteal (ML) phase of the menstrual cycle compared with the early follicular (EF) phase. On the basis of this finding, we hypothesize an augmented vestibulosympathetic reflex during the ML phase of the menstrual cycle. Muscle sympathetic nerve activity (MSNA), mean arterial pressure (MAP), and heart rate responses to head-down rotation (HDR) were measured in 10 healthy females during the EF and ML phases of the menstrual cycle. Plasma estradiol (Δ72 ± 13 pg/ml, P < 0.01) and progesterone (Δ8 ± 2 ng/ml, P < 0.01) were significantly greater during the ML phase compared with the EF phase. The menstrual cycle did not alter resting MSNA, MAP, and heart rate (EF: 13 ± 3 bursts/min, 80 ± 2 mmHg, 65 ± 2 beats/min vs. ML: 14 ± 3 bursts/min, 81 ± 3 mmHg, 64 ± 3 beats/min). During the EF phase, HDR increased MSNA (Δ3 ± 1 bursts/min, P < 0.02) but did not change MAP or heart rate (Δ0 ± 1 mmHg and Δ1 ± 1 beats/min). During the ML phase, HDR increased both MSNA and MAP (Δ4 ± 1 bursts/min and Δ3 ± 1 mmHg, P < 0.04) with no change in heart rate (Δ0 ± 1 beats/min). MSNA and heart rate responses to HDR were not different between the EF and ML phases, but MAP responses to HDR were augmented during the ML phase ( P < 0.03). Our results demonstrate that the menstrual cycle does not influence the vestibulosympathetic reflex but appears to alter MAP responses to HDR during the ML phase.
Shift in metabolic fuel in acylation-stimulating protein-deficient mice following a high-fat diet
Authors: Roy Christian , Paglialunga Sabina , Fisette Alexandre , Schrauwen Patrick , Moonen-Kornips Esther , St-Onge Josée , Hesselink Matthjis K. , Richard Denis , Joanisse Denis R. , Cianflone Katherine
Published: April 2008

ASP-deficient mice (C3 KO) have delayed postprandial TG clearance, are hyperphagic, and display increased energy expenditure. Markers of carbohydrate and fatty acid metabolism in the skeletal muscle and heart were examined to evaluate the mechanism. On a high-fat diet, compared with wild-type mice, C3 KO mice have increased energy expenditure, decreased RQ, lower ex vivo glucose oxidation (−39%, P = 0.018), and higher ex vivo fatty acid oxidation (+68%, P = 0.019). They have lower muscle glycogen content (−25%, P < 0.05) and lower activities for the glycolytic enzymes glycogen phosphorylase (−31%, P = 0.005), hexokinase (−43%, P = 0.007), phosphofructokinase (−51%, P < 0.0001), and GAPDH (−15%, P = 0.04). Analysis of mitochondrial enzyme activities revealed that hydroxyacyl-coenzyme A dehydrogenase was higher (+25%, P = 0.004) in C3 KO mice. Furthermore, Western blot analysis of muscle revealed significantly higher fatty acid transporter CD36 (+40%, P = 0.006) and cytochrome c (a marker of mitochondrial content; +69%, P = 0.034) levels in C3 KO mice, whereas the activity of AMP kinase was lower (−48%, P = 0.003). Overall, these results demonstrate a shift in the metabolic potential of skeletal muscle toward increased fatty acid utilization. Whether this is 1) a consequence of decreased adipose tissue storage with repartitioning toward muscle or 2) a direct result of the absence of ASP interaction with the receptor C5L2 in muscle remains to be determined. However, these in vivo data suggest that ASP inhibition could be a potentially viable approach in correcting muscle metabolic dysfunction in obesity.
Regulation of the fructose transporter GLUT5 in health and disease
Authors: Douard Veronique , Ferraris Ronaldo P.
Published: April 2008

Fructose is now such an important component of human diets that increasing attention is being focused on the fructose transporter GLUT5. In this review, we describe the regulation of GLUT5 not only in the intestine and testis, where it was first discovered, but also in the kidney, skeletal muscle, fat tissue, and brain where increasing numbers of cell types have been found to have GLUT5. GLUT5 expression levels and fructose uptake rates are also significantly affected by diabetes, hypertension, obesity, and inflammation and seem to be induced during carcinogenesis, particularly in the mammary glands. We end by highlighting research areas that should yield information needed to better understand the role of GLUT5 during normal development, metabolic disturbances, and cancer.
Dopamine Increases the Gain of the Input-Output Response of Rat Prefrontal Pyramidal Neurons
Authors: Thurley Kay , Senn Walter , Lüscher Hans-Rudolf
Published: April 2008

Dopaminergic modulation of prefrontal cortical activity is known to affect cognitive functions like working memory. Little consensus on the role of dopamine modulation has been achieved, however, in part because quantities directly relating to the neuronal substrate of working memory are difficult to measure. Here we show that dopamine increases the gain of the frequency-current relationship of layer 5 pyramidal neurons in vitro in response to noisy input currents. The gain increase could be attributed to a reduction of the slow afterhyperpolarization by dopamine. Dopamine also increases neuronal excitability by shifting the input-output functions to lower inputs. The modulation of these response properties is mainly mediated by D1 receptors. Integrate-and-fire neurons were fitted to the experimentally recorded input-output functions and recurrently connected in a model network. The gain increase induced by dopamine application facilitated and stabilized persistent activity in this network. The results support the hypothesis that catecholamines increase the neuronal gain and suggest that dopamine improves working memory via gain modulation.
Reference Frame Conversions for Repeated Arm Movements
Authors: Sorrento Gianluca U. , Henriques Denise Y. P.
Published: April 2008

The aim of this study was to further understand how the brain represents spatial information for shaping aiming movements to targets. Both behavioral and neurophysiological studies have shown that the brain represents spatial memory for reaching targets in an eye-fixed frame. To date, these studies have only shown how the brain stores and updates target locations for generating a single arm movement. But once a target's location has been computed relative to the hand to program a pointing movement, is that information reused for subsequent movements to the same location? Or is the remembered target location reconverted from eye to motor coordinates each time a pointing movement is made? To test between these two possibilities, we had subjects point twice to the remembered location of a previously foveated target after shifting their gaze to the opposite side of the target site before each pointing movement. When we compared the direction of pointing errors for the second movement to those of the first, we found that errors for each movement varied as a function of current gaze so that pointing endpoints fell on opposite sides of the remembered target site in the same trial. Our results suggest that when shaping multiple pointing movements to the same location the brain does not use information from the previous arm movement such as an arm-fixed representation of the target but instead mainly uses the updated eye-fixed representation of the target to recalculate its location into the appropriate motor frame.
A meta-analysis of QTL for diabetes-related traits in rodents
Authors: Schmidt Christian , Gonzaludo Nina P. , Strunk Sarah , Dahm Stefan , Schuchhardt Johannes , Kleinjung Frank , Wuschke Stefan , Joost Hans-Georg , Al-Hasani Hadi
Published: April 2008

Crossbreeding studies in rodents have identified numerous quantitative trait loci (QTL) that are linked to diabetes-related component traits. To identify genetic consensus regions implicated in insulin action and glucose homeostasis, we have performed a meta-analysis of genomewide linkage scans for diabetes-related traits. From a total of 43 published genomewide scans we assembled a nonredundant collection of 153 QTL for glucose levels, insulin levels, and glucose tolerance. Collectively, these studies include data from 48 different parental strains and >11,000 individual animals. The results of the studies were analyzed by the truncated product method (TPM). The analysis revealed significant evidence for linkage of glucose levels, insulin levels, and glucose tolerance to 27 different segments of the mouse genome. The most prominent consensus regions [localized to chromosomes 2, 4, 7, 9, 11, 13, and 19; logarithm of odds (LOD) scores 10.5–17.4] cover ∼11% of the mouse genome and collectively contain the peak markers for 47 QTL. Approximately half of these genomic segments also show significant linkage to body weight and adiposity, indicating the presence of multiple obesity-dependent and -independent consensus regions for diabetes-related traits. At least 84 human genetic markers from genomewide scans and >80 candidate genes from human and rodent studies map into the mouse consensus regions for diabetes-related traits, indicating a substantial overlap between the species. Our results provide guidance for the identification of novel candidate genes and demonstrate the presence of numerous distinct consensus QTL regions with highly significant LOD scores that control glucose homeostasis. An interactive physical map of the QTL is available online at http://www.diabesitygenes.org .
Endoscopic Optic Nerve Decompression for the Treatment of Traumatic Optic Nerve Neuropathy
Authors: Wang De-hui , Zheng Chun-quan , Qian Jiang , Barr Jennifer J. , Anderson, Jr. Ashley G.
Published: April 2008

Objective: We aimed to investigate the efficacy of endoscopic optic nerve decompression in patients with traumatic optic neuropathy. Methods: We performed a retrospective analysis of 46 patients with traumatic optic neuropathy in the Shanghai Eye, Ear, Nose and Throat Hospital between March 2002 and September 2005. All patients were first treated with methylprednisolone for 6 days. Forty-four patients (46 eyes) that did not improve with methylprednisolone treatment were offered endoscopic optic nerve decompression. Results: In 38 eyes with no light perception vision preoperatively, 21 eyes (45.6%) had improvement in visual acuity. These patients had postoperative light perception in 17 eyes, hand movement in 3 eyes and 60/200 in 1 eye. Four of 5 eyes with light perception preoperatively had postoperative vision for hand movement in 2 eyes, finger counting in 1 eye and 20/200 in 1 eye. For 3 eyes with preoperative visual acuity of hand movement, the postoperative visual acuities were 60/200, 60/200 and 120/200. Neither worsening of vision nor major complications was encountered in our series. Conclusions: We conclude that endoscopic optic nerve decompression in experienced surgeons’ hands can improve visual acuity in traumatic optic nerve neuropathy with minimal morbidity. Our results also demonstrate that even patients initially without light perception may benefit from optic nerve decompression.
Effect of Shear on Phase-Separation in Polystyrene/Poly(vinyl methyl ether)/Organoclay Nanocomposites
Authors: El-Mabrouk Khalil , Vaudreuil Sébastien , Zeghloul Abderrahim , Bousmina Mosto
Published: April 2008

Blends of polystyrene (PS)/poly(vinyl methyl ether) (PVME) modified with two types of organoclay were prepared by solution casting from toluene. The effect of clay addition on the phase separating morphology of PS/PVME blend with critical composition (25/75) was examined both under
quiescent conditions and under shear flow. The variation in critical temperature of phase separation was assessed by rheology, small angle laser light scattering (SALLS) and by on-line laser light transmission during shearing at fixed shear rate during heating. Transmission electron microscopy
and X-ray diffraction analyses were used to examine the state of delamination and distribution of clay nanoparticles with the blend matrix.
Facile Synthesis and Characterization of Potassium-Doped MnO2 Nanowires
Authors: Mukherji Aniruddh , Wang Lianzhou , Zou Jin , Auchterlonie Graeme J. , Lu Max G. Q.
Published: April 2008

A new type of potassium doped manganese oxide nanowires were synthesized using a simple hydrothermal route. The reduction of MnO–4 in the presence of acetate species led to the formation of the Multi-filamentous nanowire structure. Detailed TEM and chemical
characterizations indicated that potassium ions were homogeneously distributed in the nanowires. XPS results show a clear binding energy shift (1 eV) for K2p peak in nanowires compared with its starting material of KMnO4. Detailed synthetic condition investigation indicated
that the presence of acetate ions played an important role in the formation of such a type of nanowires other than layered structures.
Investigation of Parameters Controlling the Dielectrophoretic Assembly of Carbon Nanotubes on Microelectrodes
Authors: Dimaki Maria , Bøggild Peter
Published: April 2008

Networks of single-walled carbon nanotubes were assembled onto microelectrodes by dielectrophoresis. The dependence of the obtained networks on several assembly parameters such as bias voltage, field application time, frequency, electrode geometry and the nanotube solvent were investigated
both structurally and electrically. Reproducible differences in morphological and electrical properties were observed for the parameters investigated. Application of a bias voltage above 10 V for more than 30 seconds with nanotubes in an SDS solution, resulted in dense networks with a relatively
low resistance in the 10 kΩ regime. On the other hand, individual nanotubes and bundles were assembled with lower voltages applied for less than 10 seconds and with other nanotubes solutions. The experimental results were combined with theoretical calculations in order to find a geometry
and voltage independent threshold field for the successful assembly of nanotubes between electrodes using dielectrophoresis.
Nano-Sized Ceramic Inks for Drop-on-Demand Ink-Jet Printing in Quadrichromy
Authors: Gardini Davide , Dondi Michele , Luisa Costa Anna , Matteucci Francesco , Blosi Magda , Galassi Carmen , Baldi Giovanni , Cinotti Elenia
Published: April 2008

Nano-sized ceramic inks suitable for ink-jet printing have been developed for the four-colours CMYK (cyan, magenta, yellow, black) process. Nano-inks of different pigment composition (Co1–xO, Au0, Ti1–x–ySbxCryO2,
CoFe2O4) have been prepared with various solid loadings and their chemico-physical properties (particle size, viscosity, surface tension, ζ-potential) were tailored for the ink-jet application. The pigment particle size is in the 20–80 nm range. All
these nano-suspensions are stable for long time (i.e., several months) due to either electrostatic (high ζ-potential values) or steric stabilization mechanisms. Both nanometric size and high stability avoid problems of nozzle clogging from particles agglomeration and settling.
Nano-inks have a Newtonian behaviour with relatively low viscosities at room temperature. More concentrated inks fulfil the viscosity requirement of ink-jet applications (i.e., <35 mPa˙s) for printing temperatures in between 30 and 70 °C. Surface tension constraints for ink-jet
printing are fulfilled by nano-inks, being in the 35–45 mN˙m–1 range. The nano-sized inks investigated behave satisfactorily in preliminary printing tests on several unfired industrial ceramic tiles, developing saturated colours in a wide range of firing temperatures
(1000–1200 °C).
CdS:Mn Nanorods: Solvothermal Synthesis and Properties
Authors: Datta Anuja , Kar Soumitra , Chaudhuri Subhadra
Published: April 2008

Manganese (0.05–9 mol.%) doped CdS nanorods were synthesized via solvothermal route using ethylenediamine (En) and a mixture of En and water as the solvents. The diameters and the lengths of the doped CdS nanorods varied from 40–100 nm and 600–2500 nm, respectively,
with change in the composition of the solvents. The broad photoluminescence (PL) emission from the undoped CdS nanorods centered at ∼535 nm is found to be blue shifted to 516 nm with the incorporation of Mn in the CdS crystal structure. Also increase in the intensity of the PL was noticed
in the Mn doped CdS nanorods for both the solvent systems. Maximum PL intensity was observed for 1 mol.% Mn in case of En system and for 0.5 mol.% Mn in case of En/water system, above which quenching occurred as a result of Mn–Mn clustering. EPR study revealed six-line hyperfine splitting
for low Mn concentration in both solvent systems. Increase in the Mn concentration caused EPR signal broadening due to Mn–Mn clustering.
Structural Characterization of Nanostructured Fe-8P Powder Mixture
Authors: Tebib W. , Alleg S. , Bensalem R. , Bensebaa N. , Bentayeb F. Z. , Suñol J. J. , Grenèche J. M.
Published: April 2008

Nanostructured Fe-8P (wt%) powder mixture was prepared by high energy ball milling in a planetary ball mill (Fritsch P7) under argon atmosphere. The morphology of the particles, the phase identification and the alloying evolution process as a function of milling time are studied by
scanning electron microscopy (SEM), X-ray diffraction (XRD) and 57Fe Mössbauer spectrometry (MS), respectively. Refinement based on Rietveld method of the XRD patterns and the Mössbauer spectra analysis show that the FexP (1 < x < 2) and
Fe2P phosphide phases are the main product after 3 h of milling (∼10%). From the XRD Rietveld refinement, it is observed that the Fe2P phase disappears completely after 12 h of milling, while the Fe3P nanophase appears after 9 h and remains for larger milling
duration. The lattice structure distortion is evidenced by the lattice parameter changes ofthe milled products. A two structure state of the α-Fe(P) solid solution: α-Fe1 and α-Fe2 is confirmed by both the XRD and MS measurements.
After milling for 21 h, a mixture of a disordered two phase α-Fe(P) solid solution, Fe3P nanophase and a small amount of a paramagnetic FeP phosphide phase (∼2%) is obtained.
Preparation of Gold Nanoparticles in an Aqueous Medium Using 2-Mercaptosuccinic Acid as Both Reduction and Capping Agent
Authors: Vasilev K. , Zhu T. , Glasser G. , Knoll W. , Kreiter M.
Published: April 2008

Monolayer protected gold nanoparticles with diameters above 10 nm were prepared by a simple, one step reaction in water. 2-mercaptosuccinic acid (MSA) was used both as reduction agent for hydrogen tetrachloroaurate (HAuCl4) and as stabilizing agent for the gold nanoparticles.
Size distribution and surface chemistry were investigated by UV-Vis spectroscopy, scanning electron microscopy and Fourier Transform Infrared Spectroscopy. Particle size can be controlled by adjusting the molar portions of the reactants. The resulting particles are efficiently stabilized against
aggregation when MSA is used in a concentration of 40% and above. Below a minimum MSA concentration a long-term particle growth is observed.
Ultralong Aligned Multi-Walled Carbon Nanotube for Electrochemical Sensing
Authors: Punbusayakul Niramol , Ci Lijie , Talapatra Saikat , Surareungchai Werasak , Ajayan Pulickel M.
Published: April 2008

We have investigated electrochemical sensing properties of electrodes fabricated with ultralong aligned multi-walled carbon nanotube (MWNT) bundles synthesized using water-assisted chemical vapor deposition on aluminum (Al) and iron (Fe) coated silicon wafer with ethylene and argon/hydrogen
gas as carbon source and buffer gas respectively. Cyclic voltammograms performed on these electrodes show diffusion-controlled-reversible reaction. The dominance of radial diffusion mass transport at these electrodes was also indicated by sigmoidal-shaped voltammograms obtained at various
scan rates. These electrodes were able to sense very low concentration of ascorbic acid (∼0.7 μM) and dopamine (∼1.87 μM), two model species often used in electro-analysis. The excellent electrochemical properties along with good single species detection ability
suggest that these MWNTs are promising electrode materials for developing very sensitive chemical and/or biological sensors.
Improved In Vitro Anti-Tumoral Activity, Intracellular Uptake and Apoptotic Induction of Gemcitabine-Loaded Pegylated Unilamellar Liposomes
Authors: Celia Christian , Grazia Calvagno Maria , Paolino Donatella , Bulotta Stefania , Anna Ventura Cinzia , Russo Diego , Fresta Massimo
Published: April 2008

Anaplastic thyroid carcinoma is one of the most aggressive and lethal solid carcinomas affecting humans. A major limit of the chemotherapeutic agents is represented by their low therapeutic index. In this work, we investigated the possibility of improving the anti-tumoral activity of
gemcitabine by using pegylated unilamellar liposomes. Liposomes were made up of 1,2-dipalmitoyl-sn-glycero-3-phospocholine monohydrate/cholesterol/N-(carbonyl-methoxypolyethylene glycol-2000)-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (6:3:1 molar ratio) and they were prepared with a
pH gradient to improve the gemcitabine loading capacity. The anti-tumoral efficacy of the liposomal formulation was tested in vitro on human anaplastic thyroid carcinoma cells (ARO) in culture, comparing the effects with those of the free drug. Gemcitabine-loaded unilamellar liposomes
had a mean size ∼200 nm with a zeta potential ∼–2mV. The liposomal carrier noticeably improved the anti-tumoral activity of gemcitabine against ARO cells in terms of both dose-dependent cytotoxic effect and of drug exposition effect. Namely, gemcitabine-loaded liposomes showed
a cytotoxic effect (58.2% increase of cell mortality at 1 μM with respect to free drug) after 12 h incubation, while the free drug showed a significant activity only after 72 h incubation. Moreover, a significant effect on the cell mortality appeared at 0.1 μM and 100%
mortality was detected at a concentration of 1 μM of gemcitabine-loaded liposomes, while the free drug elicited the same effect at a concentration of 100 μM. The improved anti-tumoral activity of gemcitabine determined by the liposomal carrier was due to a greater intracellular
uptake. The intracellular gemcitabine levels as a function of time showed a sinusoidal profile with peaks after 2 h, 6 h and 11 h, related to the cellular cycle of ARO. PARP cleavage and DNA fragmentation analysis provided clear evidence of the apoptosis induction in ARO cells by treatment
with liposomally entrapped gemcitabine after 72 h incubation. Thus, gemcitabine-loaded liposomes may have a potential therapeutic relevance for the treatment of anaplastic thyroid carcinoma.
Large-Scale Synthesis and Characterization of Hexagonal Prism-Shaped SiC Nanowires
Authors: Chen Jianjun , Yang Guangyi , Wu Renbing , Pan Yi , Lin Jing , Zhai Rui , Wu Lingling
Published: April 2008

Abundant hexagonal prism-shaped SiC nanowires were synthesized on graphite substrate via heating silicon in a graphite crucible. The products were characterized using X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), Raman spectroscopy, scanning electron microscopy
(SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). The characterization first showed that the product was nanowires of β-SiC with almost a perfect hexagonal cross section. The growth was determined along [111] direction. The six side surfaces
look smooth under low magnification microscopy, but faceted at high magnification. Based on the characterization results, a formation mechanism combining vapor–solid (VS) growth mechanism and the lowest surface energy principle is proposed.
Thermogravimetric Analysis of the Interaction of Ferromagnetic Metal Atom and Multiwalled Carbon Nanotubes
Authors: Rawat Naveen , Gudyaka Russel , Kumar Mohit , Joshi Bharat , Santhanam Kalathur S. V.
Published: April 2008

This paper describes the thermal oxidative behavior of atomized iron or atomized cobalt in the presence of multiwalled carbon nanotubes (MWCNT). The thermogravimetric analysis shows the atomized iron thermal oxidation starts at about 500 °C that is absent when the atomized iron
is sintered with multiwalled carbon naonotubes. The thermal oxidation of iron in the sintered samples requires the collapse of the multiwalled carbon nanotubes. A similar behavior is observed with atomized cobalt when its oxidation requires the collapse of the nanotubes. This thermal oxidative
shift is interpreted as due to the atomized iron or atomized cobalt atom experiencing extensive overlap and confinement effect with multiwalled carbon nanotubes causing a spin transfer. This confinement effect is suggested to produce a transformation of iron from the outermost electronic distribution
of 3d64s2 to an effective configuration of 3d84s0 and for cobalt 3d74s2 to 3d94s0 producing spintronics effect.
Conducting Nanocomposites of Poly(N-vinylcarbazole) with Single-Walled Carbon Nanotubes
Authors: Maity Arjun , Sinha Ray Suprakas
Published: April 2008

The in situ solid-state polymerization of N-vinylcarbazole (NVC) at an elevated temperature in the presence of single-walled carbon nanotubes (SWCNTs) leads to the formation of new types of composite materials, the morphology and properties of which were characterized
by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and electrical property measurements. FTIR spectroscopy and XPS studies
confirmed the ability of SWCNTs to initiate the in situ polymerization of NVC monomers. FE-SEM and TEM results showed the coating of the outer surfaces of SWCNTs by the PNVC hompolymer with separation of individual SWCNTs from the bundles. Thermogravimetric analysis revealed a moderate
improvement in the thermal stability of the nanocomposites at a higher temperature region relative to the base polymer. The electrical conductivity of neat polymer dramatically improved in the presence of SWCNTs. For example, dc electrical conductivity increased from 10–16–10–12
S˙cm–1 for neat PNVC to ∼10–6 S˙cm–1 for nanocomposite containing 9 wt% SWCNTs.
Some Influences of Background Flow Conditions on the Generation of Turbulence due to Gravity Wave Breaking above Deep Convection
Authors: Lane Todd P. , Sharman Robert D.
Published: April 2008

Deep moist convection generates turbulence in the clear air above and around developing clouds, penetrating convective updrafts and mature thunderstorms. This turbulence can be due to shearing instabilities caused by strong flow deformations near the cloud top, and also to breaking gravity waves generated by cloud–environment interactions. Turbulence above and around deep convection is an important safety issue for aviation, and improved understanding of the conditions that lead to out-of-cloud turbulence formation may result in better turbulence avoidance guidelines or forecasting capabilities. In this study, a series of high-resolution two- and three-dimensional model simulations of a severe thunderstorm are conducted to examine the sensitivity of above-cloud turbulence to a variety of background flow conditions—in particular, the above-cloud wind shear and static stability. Shortly after the initial convective overshoot, the above-cloud turbulence and mixing are caused by local instabilities in the vicinity of the cloud interfacial boundary. At later times, when the convection is more mature, gravity wave breaking farther aloft dominates the turbulence generation. This wave breaking is caused by critical-level interactions, where the height of the critical level is controlled by the above-cloud wind shear. The strength of the above-cloud wind shear has a strong influence on the occurrence and intensity of above-cloud turbulence, with intermediate shears generating more extensive regions of turbulence, and strong shear conditions producing the most intense turbulence. Also, more stable above-cloud environments are less prone to turbulence than less stable situations. Among other things, these results highlight deficiencies in current turbulence avoidance guidelines in use by the aviation industry.
A Moist Benchmark Calculation for Atmospheric General Circulation Models
Authors: Lee Myong-In , Suarez Max J. , Kang In-Sik , Held Isaac M. , Kim Daehyun
Published: April 2008

A benchmark calculation is designed to compare the climate and climate sensitivity of atmospheric general circulation models (AGCMs). The experimental setup basically follows that of the aquaplanet experiment (APE) proposed by Neale and Hoskins, but a simple mixed layer ocean is embedded to enable air–sea coupling and the prediction of surface temperature. In calculations with several AGCMs, this idealization produces very strong zonal-mean flow and exaggerated ITCZ strength, but the model simulations remain sufficiently realistic to justify the use of this framework in isolating key differences between models. Because surface temperatures are free to respond to model differences, the simulation of the cloud distribution, especially in the subtropics, affects many other aspects of the simulations. The analysis of the simulated tropical transients highlights the importance of convection inhibition and air–sea coupling as affected by the depth of the mixed layer. These preliminary comparisons demonstrate that this idealized benchmark provides a discriminating framework for understanding the implications of differing physics parameterization in AGCMs.
Analysis of Atmospheric Energy Transport in ERA-40 and Implications for Simple Models of the Mean Tropical Circulation
Authors: Peters Matthew E. , Kuang Zhiming , Walker Christopher C.
Published: April 2008

An analysis of atmospheric energy transport in 22 years (1980–2001) of the 40-yr ECMWF Re-Analysis (ERA-40) is presented. In the analyzed budgets, there is a large cancellation between divergences of dry static and latent energy such that the total energy divergence is positive over all tropical oceanic regions except for the east Pacific cold tongue, consistent with previous studies. The west Pacific and Indian Oceans are characterized by a balance between diabatic sources and mean advective energy export, with a small eddy contribution. However, in the central and eastern Pacific convergence zone, total energy convergence by the mean circulation is balanced by submonthly eddies, with a small diabatic source. Decomposing the mean advective tendency into terms due to horizontal and vertical advection shows that the spatial variation in the mean advection is due largely to variations in vertical advection; these variations are further attributed to variations in the vertical profile of the vertical velocity. The eddy energy export, due almost exclusively to eddy moisture export, does not exhibit any significant seasonal variation.

The relationship between the eddies and the mean circulation is examined. Large-scale moisture diffusion is correlated with eddy moisture export on (500 km)2 spatial scales, implying that eddy activity preferentially dries narrow convergence zones over wide ones. Eddy moisture export is further linked to the depth of mean convection in large-scale convergence zones with larger eddy export associated with shallower circulations. This suggests a mechanism that could contribute to the observed variation in mean divergence profiles across the northern tropical Pacific whereby sea surface temperature gradients set the width of convergence zones and eddy activity modulates the tropospheric relative humidity and divergence profile. The importance of variations in the vertical profile of the vertical velocity and eddies in closing the energy budget implies that simple models of the mean tropical circulation should include these effects.
Recent Changes in Surface Humidity: Development of the HadCRUH Dataset
Authors: Willett Katharine M. , Jones Philip D. , Gillett Nathan P. , Thorne Peter W.
Published: April 2008

Water vapor constitutes the most significant greenhouse gas, is a key driver of many atmospheric processes, and hence, is fundamental to understanding the climate system. It is a major factor in human “heat stress,” whereby increasing humidity reduces the ability to stay cool. Until now no truly global homogenized surface humidity dataset has existed with which to assess recent changes. The Met Office Hadley Centre and Climatic Research Unit Global Surface Humidity dataset (HadCRUH), described herein, provides a homogenized quality controlled near-global 5° by 5° gridded monthly mean anomaly dataset in surface specific and relative humidity from 1973 to 2003. It consists of land and marine data, and is geographically quasi-complete over the region 60°N–40°S.

Between 1973 and 2003 surface specific humidity has increased significantly over the globe, tropics, and Northern Hemisphere. Global trends are 0.11 and 0.07 g kg−1 (10 yr)−1 for land and marine components, respectively. Trends are consistently larger in the tropics and in the Northern Hemisphere during summer, as expected: warmer regions exhibit larger increases in specific humidity for a given temperature change under conditions of constant relative humidity, based on the Clausius–Clapeyron equation. Relative humidity trends are not significant when averaged over the landmass of the globe, tropics, and Northern Hemisphere, although some seasonal changes are significant.

A strong positive bias is apparent in marine humidity data prior to 1982, likely owing to a known change in reporting practice for dewpoint temperature at this time. Consequently, trends in both specific and relative humidity are likely underestimated over the oceans.
Comparison of FASST and SNTHERM in Three Snow Accumulation Regimes
Authors: Frankenstein Susan , Sawyer Anne , Koeberle Julie
Published: April 2008

Numerical experiments of snow accumulation and depletion were carried out as well as surface energy fluxes over four Cold Land Processes Experiment (CLPX) sites in Colorado using the Snow Thermal model (SNTHERM) and the Fast All-Season Soil Strength model (FASST). SNTHERM is a multilayer snow model developed to describe changes in snow properties as a function of depth and time, using a one-dimensional mass and energy balance. The model is intended for seasonal snow covers and addresses conditions found throughout the winter, from initial ground freezing in the fall to snow ablation in the spring. It has been used by many researchers over a variety of terrains. FASST is a newly developed one-dimensional dynamic state-of-the-ground model. It calculates the ground’s moisture content, ice content, temperature, and freeze–thaw profiles as well as soil strength and surface ice and snow accumulation/depletion. Because FASST is newer and not as well known, the authors wanted to determine its use as a snow model by comparing it with SNTHERM, one of the most established snow models available. It is demonstrated that even though FASST is only a single-layer snow model, the RMSE snow depth compared very favorably against SNTHERM, often performing better during the accumulation phase. The surface energy fluxes calculated by the two models were also compared and were found to be similar.
Comparing Simulated and Measured Sensible and Latent Heat Fluxes over Snow under a Pine Canopy to Improve an Energy Balance Snowmelt Model
Authors: Marks D. , Winstral A. , Flerchinger G. , Reba M. , Pomeroy J. , Link T. , Elder K.
Published: April 2008

During the second year of the NASA Cold Land Processes Experiment (CLPX), an eddy covariance (EC) system was deployed at the Local Scale Observation Site (LSOS) from mid-February to June 2003. The EC system was located beneath a uniform pine canopy, where the trees are regularly spaced and are of similar age and height. In an effort to evaluate the turbulent flux calculations of an energy balance snowmelt model (SNOBAL), modeled and EC-measured sensible and latent heat fluxes between the snow cover and the atmosphere during this period are presented and compared. Turbulent fluxes comprise a large component of the snow cover energy balance in the premelt and ripening period (March–early May) and therefore control the internal energy content of the snow cover as melt accelerates in late spring. Simulated snow cover depth closely matched measured values (RMS difference 8.3 cm; Nash–Sutcliff model efficiency 0.90), whereas simulated snow cover mass closely matched the few measured values taken during the season. Over the 927-h comparison period using the default model configuration, simulated sensible heat H was within 1 W m−2, latent heat LυE within 4 W m−2, and cumulative sublimation within 3 mm of that measured by the EC system. Differences between EC-measured and simulated fluxes occurred primarily at night. The reduction of the surface layer specification in the model from 25 to 10 cm reduced flux differences between EC-measured and modeled fluxes to 0 W m−2 for H, 2 W m−2 for LυE, and 1 mm for sublimation. When only daytime fluxes were compared, differences were further reduced to 1 W m−2 for LυE and <1 mm for sublimation. This experiment shows that in addition to traditional mass balance methods, EC-measured fluxes can be used to diagnose the performance of a snow cover energy balance model. It also demonstrates the use of eddy covariance methods for measuring heat and mass fluxes from snow covers at a low-wind, below-canopy site.
The Potential Impact of Using Persistence as a Reference Forecast on Perceived Forecast Skill
Authors: Mittermaier Marion P.
Published: April 2008

Skill is defined as actual forecast performance relative to the performance of a reference forecast. It is shown that the choice of reference (e.g., random or persistence) can affect the perceived performance of the forecast system. Two scores, the equitable threat score (ETS) and the odds ratio benefit skill score (ORBSS), were chosen to show the impact of using a persistence forecast, first using some simple hypothetical scenarios and second for actual forecasts from the Met Office Unified Model (UM) of precipitation, total cloud cover, and visibility during 2006. Overall persistence offers a sterner test of true forecast added value and accuracy, but using a more realistic reference may come at a cost. Using persistence introduces an additional degree of freedom to the skill assessment, which may be rather variable for “weather parameters.” Ultimately, the aim of any forecasting system should be to achieve a substantive separation between the inherent skill of the reference (which represents basic predictability) and the actual forecast.
Defiance Theory and Life Course Explanations of Persistent Offending
Authors: Bouffard Leana Allen , Piquero Nicole Leeper
Published: April 2008

Criminologists have long grappled with the varying effect of sanctions. In an effort to clarify these divergent effects, Sherman (1993) delineated a general theory of sanction effects, termed defiance theory. Defiance theory anticipates that there are four necessary conditions for defiance to occur: (a) the sanction must be perceived as unfair; (b) the offender must be poorly bonded; (c) the sanction must be perceived as stigmatizing; and (d) the offender denies the shame produced by the sanction. This study provides one of the first empirical assessments of defiance theory. In addition, defiance theory is examined within the life-course perspective, and analyses address trajectories of offending. Using data from the 1945 Philadelphia Birth Cohort, the results yield promising support for the theory.
Form of Urban Local Government in India
Authors: Aijaz Rumi
Published: April 2008

The role of urban local governments in India has become extremely challenging. To ensure that demands of the urban population are addressed properly, the Indian government has initiated various policy reforms to strengthen local governments. This article describes the form of urban local government in India in the context of recent municipal reforms. Evolution of municipalities, their typology and constitution, legislation, duties, composition, management and finance practices are some aspects covered. It is concluded that municipalities in India are being empowered in various ways with the intention that they would emerge as viable units of governance at the local level.
Gender and Employment in Rural Afghanistan, 2003—5
Authors: Maletta Hector
Published: April 2008

This article explores female employment in rural Afghanistan, based on the 2003 and 2005 Nationwide Risk and Vulnerability Assessments (NRVA) covering thousands of households. Rural female employment involves about a quarter of rural women and a quarter of rural households. Female employment rates are much lower across the conservative southern belt. A majority of rural working women are in wage jobs, paid much less than men. Few employed women have control over their earnings. Better-educated rural women have higher participation and lower unemployment, especially in medium and better-off households. Female unemployment rates are double men's rates. The article highlights priorities for research and policy implications.
Sustainable Village Organizations, the Successful Route to Sustainable Livelihoods? A Case Study in the North-West Frontier Province of Pakistan
Authors: Ur-rehman Mujib
Published: April 2008

The study is based on the impact of development interventions on the rural households in the Abbottabad district of Pakistan. Methodological approaches used include a qualitative analysis of natural resource management and NGOs' impact on development activities and quantitative analysis of households' livelihood status and strategies. The key findings are that the role of social capital can ensure sustainable natural resource management and sustainable livelihood improvement activities. Formation of community-based organizations can lead to the formation of social capital that is much needed for other management and livelihood support activities. Also, natural resource management and livelihood improvement activities need to be interrelated with each other to involve the poor as they need incentives.
Student Politics and Activism in Zimbabwe
Authors: Zeilig Leo
Published: April 2008

Student activism has made an important contribution to the struggle for democracy in Zimbabwe. In the first years of independence students were among the most fearsome defenders of the regime. Three broad periods of student activism can be identified. The first pro-government period was followed by a violent break with the regime in 1988, the second period saw students declare that they were `the voice of the voiceless'. With the onset of structural adjustment programmes in the early 1990s, the privileged status of students in higher education was rapidly eroded. The third period emerged after 1995 as student activism converged with the urban revolt that was beginning to shake Zimbabwe. This article assesses the role of student activism in Zimbabwe.
Developmental Links of Very Early Phonological and Language Skills to Second Grade Reading Outcomes
Authors: Puolakanaho Anne , Ahonen Timo , Aro Mikko , Eklund Kenneth , Leppänen Paavo H. T. , Poikkeus Anna-Maija , Tolvanen Asko , Torppa Minna , Lyytinen Heikki
Published: April 2008

The authors examined second grade reading accuracy and fluency and their associations via letter knowledge to phonological and language predictors assessed at 3.5, 4.5, and 5.5 years in children in the Jyväskylä Longitudinal Study of Dyslexia. Structural equation modeling showed that a developmentally highly stable factor (early phonological and language processing [EPLP]) behind key dyslexia predictors (i.e., phonological awareness, short-term memory, rapid naming, vocabulary, and pseudoword repetition) could already be identified at 3.5 years. EPLP was significantly associated with reading and spelling accuracy and by age with letter knowledge. However, EPLP had only a minor link with reading fluency, which was additionally explained by early letter knowledge. The results show that reading accuracy is well predicted by early phonological and language skills. Variation in fluent reading skills is not well explained by early skills, suggesting factors other than phonological core skills. Future research is suggested to explore the factors behind the development of fast and accurate decoding skills.
Religion, Pragmatic Fundamentalism and the Transformation of the Northern Ireland Conflict
Authors: Ganiel Gladys , Dixon Paul
Published: April 2008

Since 11 September 2001, the religious dimension of conflict has been the focus of increasing attention. In The Clash of Civilizations, Huntington has identified the West in religious—cultural terms, as Christian with a dominant democratic culture emphasizing tolerance, moderation and consensus. The persistence of conflict in Northern Ireland among `White' Protestant and Catholic Christians undermines this simplistic argument and demands a more subtle understanding of the role of religion and fundamentalism in contemporary conflict. Modernization theory — which is echoed among some theorists of globalization — had predicted the declining importance of religion as the world became industrialized and increasingly interconnected. This is echoed by those who argue that the Northern Ireland conflict is `ethno-national' and dismiss the role of religion. On the other hand, others have claimed that the conflict is religious and stress the role of Protestant fundamentalism. This article draws on new evidence from Northern Ireland of the complex and subtle ways in which religion impacts on the conflict there, incorporating insights about the pragmatism of fundamentalist Protestants and how religious actors are contributing to conflict transformation. This analysis leads to three broader conclusions about understanding conflicts with religious dimensions. First, the complexity of religion must be understood, and this includes a willingness to recognize the adaptability of fundamentalisms to particular contexts. Second, engaging with fundamentalists and taking their grievances seriously opens up possibilities for conflict transformation. Third, governments and religious actors within civil society can play complementary roles in constructing alternative (religious) ideologies and structures as part of a process of transformation. In a world in which the impact of religion is persistent, engaging with the religious dimension is a vital part of a broader-based strategy for dealing with conflict.
A Critical Examination of ELT in Thailand
Authors: Baker Will
Published: April 2008

With the increasingly significant role that English language teaching (ELT) is playing in Asian contexts, it is important to gain a better understanding of the use of English as a medium of intercultural communication in Asia. In doing so, ELT practices may be better able to adapt themselves to the intercultural communicative needs of local contexts. This paper argues that an essential element in fostering successful intercultural communication is developing cultural awareness as part of ELT pedagogy. To illustrate this, a case study of Thailand is presented examining English use, English teaching policy and practice, and local cultural attitudes towards ELT. This then leads to suggestions on how locally relevant intercultural communicative practices can form part of ELT classroom pedagogy in Thailand with the aim of developing learners' cultural awareness. It is argued that similar analyses may be applied to other Asian contexts, which may share features with the Thai context. This can lead to the development of teaching practices, which through engaging learners in intercultural reflection will result in English language users who are better able to manage intercultural communication through English.