bluuebunny/crossref_metadata_2025 huggingface dataset:
Ontogeny of 5‐HT neurons in the brainstem of the lamprey, Petromyzon marinus
Authors: Antri Myriam , Cyr André , Auclair François , Dubuc Réjean
Published: February 2006

This study examined the spatial and temporal distribution of serotonin‐immunoreactive (5‐HT‐ir) neurons in the brainstem of Petromyzon marinus at three developmental stages, larval, postmetamorphic, and reproductive. Computer‐assisted 3‐D reconstructions were made of the three main 5‐HT‐ir neuron groups. The rostralmost brainstem group was located near the posterior commissure, the second group at the isthmus, and the third group in the bulbar area. For each of those groups, the distribution of the 5‐HT‐ir neurons was very similar in the three developmental stages examined, suggesting that the 5‐HT system is relatively mature early in larval animals. The soma of 5‐HT‐ir neurons increased in size and their dendritic fields increased in complexity with development. Furthermore, the number of 5‐HT‐ir neurons in each group increased significantly from the larval to the reproductive stage. To determine whether this was due to the genesis of 5‐HT neurons, bromodeoxyuridine (BrdU) was injected into larval, metamorphosing, and postmetamorphic lampreys. These experiments revealed a few neurons colocalizing BrdU and 5‐HT in metamorphosing animals. Taken together, the present results suggest that 5‐HT neurons increase in number during maturation and that neurogenesis could, at least partially, contribute to the appearance of new 5‐HT cells at different developmental stages. J. Comp. Neurol. 495:788–800, 2006. © 2006 Wiley‐Liss, Inc.
Expression of qBrn‐1, a new member of the POU gene family, in the early developing nervous system and embryonic kidney
Authors: Lan Lei , Liu Mingnan , Liu Yang , Liu Ying , Zhang Wei , Xue Jinxiao , Xue Zhigang , He Rongqiao
Published: February 2006

It has been shown that POU domain genes play critical roles in the development of the nervous system. We have obtained a new member of the class III POU domain genes, qBrn‐1, from the cDNA library of embryonic day 5 quail and have made an extensive expression pattern analysis of qBrn‐1 and qBrn‐2 throughout the early embryonic development by in situ hybridization. With a specific antibody we prepared, further analysis by immunohistochemistry showed that the location of qBrn‐1 protein was consistent with that of the transcripts in the early developing quail. Our results showed that both qBrn‐1 and qBrn‐2 were preferentially expressed in the developing central nervous system, and their transcripts were initially detected in the neural plate and later in the distinct regions of the neural tube with a stage‐dependent pattern. Moreover, their expression was also detected in both notochord and neural crests. However, qBrn‐1 signal, different from qBrn‐2, was more widely found in the auditory pits, branchial arches, and in the mesodermal components of the developing kidney. And the expression of qBrn‐1 in nephric region was earlier and wider than that of mouse Brn‐1, suggesting the characteristic function of qBrn‐1 in the kidney formation. The distinct dynamic expression patterns of qBrn‐1 and qBrn‐2 indicate multiple roles of the class III POU genes in quail neurogenesis and organogenesis. Developmental Dynamics 235:1107–1114, 2006. © 2006 Wiley‐Liss, Inc.
Personality disorder traits evident by early adulthood and risk for eating and weight problems during middle adulthood
Authors: Johnson Jeffrey G. , Cohen Patricia , Kasen Stephanie , Brook Judith S.
Published: February 2006

Objective:

The current article investigates the association of personality disorder (PD) with the subsequent development of eating and weight problems.

Method:

Psychiatric interviews were administered to a community‐based sample of 658 individuals at mean ages 14, 16, 22, and 33 years.

Results:

Individuals with PD by age 22 were at an elevated risk for eating disorders at mean age 33 years. PDs were associated with risk for onset of binge eating, purging, daily dietary restriction, and obesity among individuals without a history of these problems. Borderline and histrionic PD symptoms were associated with recurrent binging and purging at mean age 33 years. Antisocial and schizotypal symptoms were associated with recurrent binging and obesity at mean age 33 years. Depressive PD symptoms were associated with recurrent binging and dietary restriction at mean age 33 years.

Conclusion:

PD symptoms, evident by early adulthood, may be associated with the risk for the development of eating and weight problems by middle adulthood. © 2006 Wiley Periodicals, Inc., Int J Eat Disord, 2006
An experimental investigation of recruitment bias in eating pathology research
Authors: Moss Erin L. , von Ranson Kristin M.
Published: February 2006

Previous, uncontrolled research has suggested a bias may exist in recruiting participants for eating disorder research. Recruitment biases may affect sample representativeness and generalizability of findings.

Objective:

This experiment investigated whether revealing that a study's topic was related to eating disorders created a self‐selection bias.

Method:

Young women at a university responded to advertisements containing contrasting information about the nature of a single study. We recruited one group by advertising the study under the title “Disordered Eating in Young Women”(n = 251) and another group using the title “Consumer Preferences” (n = 259).

Results:

Results indicated similar levels of eating pathology in both groups, so the different recruitment techniques did not engender self‐selection. However, the consumer preferences group scored higher in self‐reported social desirability.

Conclusion:

The level of information conveyed in study advertising does not impact reporting of eating disturbances among nonclinical samples, although there is evidence social desirability might. © 2006 Wiley Periodicals, Inc., Int J Eat Disord, 2006
Associations among postpartum depression, eating disorders, and perfectionism in a population‐based sample of adult women
Authors: Mazzeo Suzanne E. , Slof‐Op't Landt Margarita C.T. , Jones Ian , Mitchell Karen , Kendler Kenneth S. , Neale Michael C. , Aggen Steven H. , Bulik Cynthia M.
Published: February 2006

Objective

The current study investigated associations among eating disorders, depressive symptoms during pregnancy and postpartum, and perfectionism in a population‐based sample of women.

Method

Females who reported ≥1 pregnancy (N = 1,119) completed questionnaires assessing perfectionism, eating disorder symptomatology, and depression during pregnancy and postpartum. Information regarding participants' history of major depressive disorder (MDD) was also available from structured psychiatric interviews completed during a previous wave of data collection.

Results

Depressive symptoms during pregnancy and postpartum were high among women with a history of eating disorders. Both binge eating disorder (BED) and bulimia nervosa (BN) were positively associated with symptoms of postpartum depression (PPD), even when lifetime MDD was controlled. However, logistic regression indicated that women with a history of BN and BED are at particular risk of developing PPD symptomatology. Linear regression analyses conducted with the subset of the sample who endorsed a PPD screening item suggested that the severity of PPD symptomatology may be attributable to Concern Over Mistakes, a specific aspect of perfectionism.

Conclusion

These results highlight the importance of assessing specific features of perfectionism. In addition, they suggest that women with BN, BED, or high Concern over Mistakes may be at particular risk of developing PPD symptoms, and could benefit from prenatal screening. © 2006 by Wiley Periodicals, Inc., Int J Eat Disord, 2006
Trial of a psychoeducational eating disturbance intervention for college women: A replication and extension
Authors: Stice Eric , Orjada Kendra , Tristan Jennifer
Published: February 2006

Objective

We conducted a controlled trial of a psychoeducational eating disturbance intervention to replicate the positive findings observed in the preliminary evaluation of this intervention and to determine whether the effects persist for a longer follow‐up period.

Method

College women who took the psychoeducational class and a matched control sample of students (N = 95) completed pretest, posttest, and 6‐month follow‐up surveys.

Results

Intervention participants showed significantly greater reductions in thin‐ideal internalization, body dissatisfaction, dieting, and eating disorder symptoms, as well as significantly less weight gain, relative to matched controls over the study period. Intervention effects tended to be larger at 6‐month follow‐up than at posttest.

Conclusion

These findings suggest that the intervention effects for eating disorder risk factors and eating disorder symptoms, as well as the weight gain prevention effects, are reproducible and persist over time. This intervention has both mental health and public health significance. © 2006 by Wiley Periodicals, Inc., Int J Eat Disord, 2006
Synthesis of Fused‐Ring Indenes by Ruthenium‐Catalyzed Ring‐Closing Metathesis
Authors: Silver Satu , Leino Reko
Published: February 2006

The preparation of new 1,2‐unsymmetrically substituted fused‐ring indenes from dialkenyl precursors by utilization of the ruthenium‐catalyzed ring‐closing metathesis is described. By analogous strategy, 1,3‐substituted fused‐ring indenes with medium‐ring sizes have also been synthesized. For bis(allylsilyl)indene, the formation of a 1,3‐fused ringappears to be prevented by ring strain and a 1,1‐spiro compound is obtained instead due to rearrangement of the substituents. The rearrangement is enabled by the [1,5]‐silatropic shifts operating in silyl‐substituted cyclopentadienyl compounds. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Silylformylation – Fluoride‐Assisted Aryl Migration of Acetylenic Derivatives in a Versatile Approach to the Synthesis of Polyfunctionalised Compounds
Authors: Aronica Laura Antonella , Raffa Patrizio , Valentini Giulia , Caporusso Anna Maria , Salvadori Piero
Published: February 2006

Polyfunctionalised aldehydes and dihydropyrans are prepared from easily available functionalised 1‐alkynes through a two‐step silylformylation/aryl migration sequence. The silylformylation process is performed under mild experimental conditions and affords the corresponding β‐silylalkenals in high yields. The fluoride‐promoted migration step occurs instantaneously with quantitative conversion. The chemo‐, regio‐ and stereoselectivity can be modulated according to the nature and the position of the functional group on the acetylene precursors. When a good leaving group is present in the ω position of the aliphatic chain of the alkyne a cyclisation product is obtained, while α,β‐unsaturated aldehydes are generated from propargylic tosylamides. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Studies Directed towards the Enantioselective Synthesis of Ethisolide and Isoavenaciolide
Authors: Blot Virginie , Reboul Vincent , Metzner Patrick
Published: February 2006

An asymmetric synthesis of an analog of ethisolide has been achieved by using as key steps two σ[3,3] rearrangements stereocontrolled by a sulfinyl group. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Self‐Assembling of Redox‐Active Atrazine Poly(ethylenimine) Conjugates – Interfacial Electrochemical and Spectroscopic Characterization
Authors: Chen Zhaohui , Salmain Michèle , Pradier Claire‐Marie , Fischer‐Durand Nathalie , Pailleret Alain , Bedioui Fethi , Zanna Sandrine
Published: February 2006

Thin films of polymers tethered with both atrazine haptens and ferrocenyl (Fc) probes were formed on polycrystalline gold electrodes by taking advantage of the facile formation of self‐assembled monolayers (SAMs) of thiolates. These films were characterized by polarization modulation Fourier transform infrared reflection–absorption spectrometry (PM‐IRRAS), X‐ray photoelectron spectroscopy (XPS) and cyclic voltammetry. The combination of these techniques gave a full insight into the structure and the binding mode of the polymers and provided useful quantitative information about both Fc entity and atrazine hapten surface density. This may open the way to a new type of immunosensor for atrazine monitoring.
Voltammetric Studies of Parallel Electrode Processes Under Low Ionic Strength Conditions. Influence of Convection
Authors: Nowicka Anna Maria , Donten Mikolaj , Palys Marcin , Van den Bossche Bart , Stojek Zbigniew
Published: February 2006

It is known that either a very strong enhancement or an almost complete depression of the height of one of two waves can be obtained when two analytes (one appropriately charged and one uncharged) are present in a quiet solution containing no supporting electrolyte. In this paper we examine whether these effects can be extended for solutions with forced convection. Three two‐analyte mixtures were examined voltammetrically under conditions of no added supporting electrolyte and added convection. The first mixture (1,1′‐ferrocenedimethanol and ferrocenesulfonate anion) changes its total charge from −1 to +1 after electrooxidation of both components. Under all applied conditions, the introduction of convection caused an increase of both waves without changing the wave height ratio. A similar behavior was observed for the mixture of ferrocene and 1,1′‐ferrocenedimethanol. For this system the total charge changes from 0 to +2. A substantial influence of convection on the ratio of two waves was found for the third mixture: ferrocene and ferrocenylmethyltrimethylammonium cation (total charge changes from +1 to +3). For this system the convection strongly depressed the migrational effects. The obtained experimental results were verified with simulations using software MIOTRAS. This software is capable of modeling diffusion, migration, convection and following homogenous reactions. The agreement between experiment and simulations was fairly good.
Determination of Dimethoate in Olive Oil by Adsorptive Stripping Square‐Wave Voltammetry
Authors: Díaz T. Galeano , Guiberteau A. , Soto M. D. López , Ortiz J. M.
Published: February 2006

A method for the determination of dimethoate in olive oil by adsorptive stripping square‐wave voltammetry has been developed on the base that this pesticide is hydrolyzed in basic media giving rise to an adsorptive‐reductive peak at −0.780 V. Extraction of dimethoate from olive oil with ethanol‐water and posterior clean‐up with C18 cartridges is carried out. Response Surface Methodology has been used for the optimization of the extraction procedure. A matrix effect is observed in olive oil extract; therefore the standard addition method must be used. The detection limit is 19.00 ng g−1 and recoveries for three levels of fortification are ranged from 79.9% to 104.5%.
The Electrochemistry of Tetraphenyl Porphyrin Iron(III) Within Immobilized Droplets Supported on Platinum Electrodes
Authors: Munoz Rodrigo A. A. , Banks Craig E. , Davies Trevor J. , Angnes Lucio , Compton Richard G.
Published: February 2006

For the first time, the voltammetry of an ensemble of immobilized benzonitrile microdroplets containing 5,10,15,20‐tetraphenyl‐21H,23H‐porphine iron (III) chloride, TPPFeCl immobilized at platinum electrodes immersed in various aqueous electrolytes has been explored. The reduction of TPPFeCl was observed with the voltammetric response seen to be highly dependent on the nature of ions in the surrounding aqueous phase. Unlike voltammetry in purely homogeneous solution the nature of the aqueous electrolyte can influence the voltammetry in the droplet phase. The electrochemical reduction of TPPFeCl contained within tetrabutylammonium chloride (TBACl) supported benzonitrile (PhCN) microdroplets immersed into an aqueous solution of TBACl was first studied. During TPPFeCl reduction the resulting [TPPFeCl]− species is stabilized due to the excess of chloride anions inside the oil droplet. Voltammograms of homogeneous solutions of PhCN supported with TBACl show similar chemically reversible process which is also attributed to the stable [TPPFeCl]− species. This anion stabilization was not observed when the oil droplets were supported with tetrabutylammonium perchlorate (TBAP) or when the PhCN solution bathing the microdroplet ensemble was supported with TBAP resulting in a chemically irreversible process. The voltammetry of unsupported droplets immobilized on a platinum electrode immersed in different aqueous electrolytes was also explored and the fate of the [TPPFeCl]− species formed considered during the reduction sweep. Similarities and difference to voltammetry in purely homogeneous media are noted and the use of droplet voltammetry provides complimentary information.
Effects of intermediate load on damping of synchronous generator
Authors: Aree P.
Published: February 2006

The transfer‐function block‐diagram model of a single‐machine infinite‐bus power system, originally developed by Heffron and Phillips, has been a popular analytical tool amongst power system engineers for explanation and assessment of synchronous generator dynamic behaviors. Since this model simply accounts for the generator field circuit with none of the damper circuits, it may not always give a realistic transient response. Moreover, the model considers only a grid‐system load without local and intermediate loads. Hence, effects of these loads together with the damper circuits on electromechanical damping have not yet been completely studied. In this paper, the Heffron‐Phillips's model has been advanced to incorporate an intermediate load plus one additional damper circuit in the q‐axis. The upgraded model demonstrates a great influence of the intermediate load together with the q‐axis damper circuit on the electromechanical damping and the dynamic interaction between the field and damper flux linkages. The study shows the key contributions of load to rise and fall of the damping. It appears that the electromechanical damping can be improved with regard to the unity power‐factor load through increasing in the natural damping and decreasing in the automatic voltage regulator (AVR) negative damping torques. Nevertheless, the damping is mostly declined, when the load power factor is poor. Moreover, it is markedly changed in relation to various locations of load. The damping characteristics of synchronous generator are investigated using the eigenvalue and frequency response methods. Copyright © 2006 John Wiley & Sons, Ltd.
A new method for screening the contingencies before dynamic security assessment of a multimachine power system
Authors: Salam M. A. , Ahmed S. Shahnawaz
Published: February 2006

This paper proposes a novel method for identifying the faults that would impact the transient stability of a multimachine power system. In this method each synchronous machine's swing equation is formulated in the form of a closed loop transfer function in Laplace domain (s‐plane). The duration of a fault under consideration, and the changes of maximum electrical power output of the machine during and after the fault are included in the same transfer function. Then the narrowest possible range containing the real part of the ‘dominant’ root of each machine's characteristic equation is identified on the real axis of s‐plane. This is because it is the real part that decides whether the transient response would sustain or subside. If the average of the lower limits of the real parts of dominant roots for all the machines is in the left half but very close to the imaginary axis (poorly damped) or in the right half of the s‐plane (absence of damping), the system as a whole is unstable under the considered fault. The proposed method is extremely fast. An extensive digital simulation test and comparison of the proposed method with a conventional step‐by‐step (SBS) numerical integration method has been done on a 25‐machine practical system belonging to Bangladesh Power Development Board (BPDB), and good agreements observed for an array of fault scenarios. The faults for which the aforesaid average lower limit is in the left half plane but its distance from imaginary axis is marginally above or below an established minimum value, can be further investigated by a detailed time domain simulation (TDS) transient stability analysis technique. Thus the proposed method is useful for real‐time screening of the contingencies (e.g., faults) before being subjected to a full‐scale dynamic security analysis in a power system of any size with any number of machines. Copyright © 2006 John Wiley & Sons, Ltd.
Contribution to the definition of a permanent magnet motor with reduced production cost for the electrical vehicle propulsion
Authors: Neji Rafik , Tounsi Souhir , Sellami Fayçal
Published: February 2006

This paper deals with a methodology for the design of a permanent magnet motor dedicated for traction. Several structures to reduce the permanent magnet motor production cost are explored. The most promising is an axial flux modular structure with straight slots and concentrated windings. Optimisation procedures are presented and applied to find these structures. An analytic dimensioning step is carried out simultaneously with a finite element electromagnetic modelling step so as to validate gradually the computational analysis. Then, a fine‐tuned finite element model is realised dynamically so as to validate wave forms that depend strongly on the machine geometry as well as on the electromagnetic motor torque. This study has allowed the entire validation of the analytic sizing computations. Copyright © 2006 John Wiley & Sons, Ltd.
An efficient approach for the load‐frequency control and its role under the conditions of deregulated environment
Authors: Stojkovic Branko
Published: February 2006

This paper describes an specific approach to resolving problem of load frequency (LF) control in the power system of Montenegro ( Serbia and Montenegro). The complete LF controller was developed, coded, and implemented on the single PC computer ‘from the zero’ by the Company's staff in a fast, feasible, and cost‐effective manner. Its extremely high ‘in‐field’ efficiency was achieved by: the compact design of the controller, the implementation of the algorithm for efficient filtering of Control Error, the implementation of the algorithm for minimizing of the regulating units movement, as well as the feed‐back algorithm for permanent adjustment of the tie‐lines power measurements. All details on these algorithms are given. The official field results for the 6 month exploitation have confirmed the top regulating success in the Second UCTE Synchronous Zone. The Electric Power Company of Montenegro (EPCG) was recently subjected to enacting of the new Energy Law, and to the promoting of the free electricity market. So, the additional modifications were made at the AGC controller to meet the requirements of deregulation processes. Thus, the AGC system keeps track of the momentary active power imbalance, detects it, corrects it and communicates an adequate amount of the balance energy service (BES) power, on the 15‐minute basis, to the real‐time part of the market operating system (MOS), where it will be allocated to the real time market (RTM) balancing resources. Copyright © 2006 John Wiley & Sons, Ltd.
Deciphering human prehistory through the geoarcheological study of cave sediments
Authors: Goldberg Paul , Sherwood Sarah C.
Published: February 2006

Throughout human history, caves and rockshelters have been favored habitation places. These unique environments preserve sediments derived from an assortment of geological and human processes that are typically absent or masked at open‐air sites. Cave sediments are parts of larger stratigraphic frameworks that can reflect environmental changes, shifting microenvironments, and the nature of human activity within these confined and sheltered spaces. Stone tools and faunal material compose the artifact assemblages from caves that are typically studied. Cave sediments, on the other hand, which encase the archeological finds and which have both geological and human origins, have been understudied relative to traditional artifacts, in spite of their ubiquity and importance. Thus, anthropogenic sediments, the most striking of which are organic‐rich deposits, and combustion features merit the same attention as any other artifacts that result from human activities and behaviors.

The purpose of this paper is to highlight some of the most salient aspects of prehistoric cave sediments and the processes revealed by recent studies of these accumulations. We review methods and techniques that are used to analyze cave sediments and illustrate how their careful study can be used to reconstruct local and regional cave environments, as well as the nature of the human activities that produced them. Finally, we show how such study can place important constraints on our archeological interpretations, ultimately having a profound effect on how we decipher human prehistory.
Gamma stochastic volatility models
Authors: Abraham Bovas , Balakrishna N. , Sivakumar Ranjini
Published: February 2006

This paper presents gamma stochastic volatility models and investigates its distributional and time series properties. The parameter estimators obtained by the method of moments are shown analytically to be consistent and asymptotically normal. The simulation results indicate that the estimators behave well. The in‐sample analysis shows that return models with gamma autoregressive stochastic volatility processes capture the leptokurtic nature of return distributions and the slowly decaying autocorrelation functions of squared stock index returns for the USA and UK. In comparison with GARCH and EGARCH models, the gamma autoregressive model picks up the persistence in volatility for the US and UK index returns but not the volatility persistence for the Canadian and Japanese index returns. The out‐of‐sample analysis indicates that the gamma autoregressive model has a superior volatility forecasting performance compared to GARCH and EGARCH models. Copyright © 2006 John Wiley _ Sons, Ltd.
Non‐linear, non‐parametric, non‐fundamental exchange rate forecasting
Authors: Gradojevic Nikola , Yang Jing
Published: February 2006

This paper employs a non‐parametric method to forecast high‐frequency Canadian/US dollar exchange rate. The introduction of a microstructure variable, order flow, substantially improves the predictive power of both linear and non‐linear models. The non‐linear models outperform random walk and linear models based on a number of recursive out‐of‐sample forecasts. Two main criteria that are applied to evaluate model performance are root mean squared error (RMSE) and the ability to predict the direction of exchange rate moves. The artificial neural network (ANN) model is consistently better in RMSE to random walk and linear models for the various out‐of‐sample set sizes. Moreover, ANN performs better than other models in terms of percentage of correctly predicted exchange rate changes. The empirical results suggest that optimal ANN architecture is superior to random walk and any linear competing model for high‐frequency exchange rate forecasting. Copyright © 2006 John Wiley & Sons, Ltd.
Potentiation of the NMDA receptor‐mediated responses through the activation of the glycine site by microglia secreting soluble factors
Authors: Hayashi Yoshinori , Ishibashi Hitoshi , Hashimoto Kenji , Nakanishi Hiroshi
Published: February 2006

We have previously reported that both transferred microglia and microglia‐conditioned medium (MCM) potentiated the N‐methyl‐D‐aspatate (NMDA) receptor‐mediated synaptic responses in cortical neurons. To elucidate the mechanism underlying the potentiation of NMDA receptor‐mediated responses by microglia, we examined the effects of MCM on NMDA‐induced inward currents in mechanically dissociated hippocampal CA1 neurons under whole‐cell patch recordings. MCM potentiated the amplitude of NMDA‐induced currents up to 10‐fold in a dose‐dependent manner, and this effect of MCM remained even after boiling or cutting off molecules with a molecular mass more than 3 kDa. In the presence of glycine with a concentration sufficient to saturate the NMDA receptor glycine site, MCM failed to further potentiate the NMDA‐induced currents. The glycine site antagonist 5, 7‐dichrolokynurenic acid, significantly inhibited the effects of MCM. The effect of MCM was still observed even after treatment with D‐amino acid oxidase, a D‐serine degrading enzyme. On the other hand, MCM had no significant effect on the voltage‐dependent Mg2+ blockade of NMDA receptors. Furthermore, MCM enhanced the formation of the long‐term potentiation in the Schaffer collateral pathway‐CA1 pyramidal cell synapses. Using a high performance liquid chromatography system, we found the levels of both glycine and L‐serine in MCM to be significantly higher than those in the control medium. It was also noted that an increased glycine productivity of microglia was observed in the hippocampus in the acute phase of neuronal injury. These observations strongly suggest that glycine is a major causative molecule released from microglia that potentiates the NMDA‐induced currents. © 2006 Wiley‐Liss, Inc.
Annexin III implicated in the microglial response to motor nerve injury
Authors: Konishi Hiroyuki , Namikawa Kazuhiko , Kiyama Hiroshi
Published: February 2006

To identify proteins implicated in peripheral nerve regeneration, we performed two‐dimensional polyacrylamide gel electrophoresis and subsequent mass spectrometry analysis using nerve‐injured hypoglossal nuclei of rat. We have identified annexin III (ANX III/ANX A3) as an induced protein after rat hypoglossal nerve injury. ANX III is known as a Ca2+‐dependent phospholipid‐binding protein, but its physiological function is mostly unknown. By in situ hybridization and immunohistochemistry, we demonstrated that ANX III expression was induced specifically in activated (axotomy‐stimulated) microglia after nerve injury. ANX III was the most prominent ANX expressed in microglia of the major ANX family members (ANX I‐VI). Hybridization signals for other ANX mRNAs (II, IV, V, and VI) were mainly observed in neuronal cells, and no significant hybridization signal for ANX I mRNA was detected in hypoglossal nuclei. In cultured microglia, ATP treatment induced ANX III translocation to the ruffling membrane where F‐actin was accumulated. Further in vitro studies revealed that ANX III was not secreted and had F‐actin binding activity in a Ca2+‐dependent manner. These results suggest that ANX III may be a Ca2+‐dependent mediator between phospholipids and F‐actin in microglia stimulated by peripheral nerve injury. © 2006 Wiley‐Liss, Inc.
Neuronal hyperactivity induces astrocytic expression of neurocan in the adult rat hippocampus
Authors: Schwarzacher Stephan W. , Vuksic Mario , Haas Carola A. , Burbach Guido J. , Sloviter Robert S. , Deller Thomas
Published: February 2006

Extracellular matrix molecules are involved in the cellular functions of proliferation, migration, morphological differentiation, and synaptic plasticity. One candidate molecule of the extracellular matrix is the chondroitin sulfate proteoglycan neurocan. To determine whether neurocan expression is regulated by neuronal activity in the adult rat brain, we studied changes in hippocampal neurocan mRNA and protein expression following electrical stimulation of the perforant pathway in urethane‐anesthetized rats. After 24 h of intermittent, unilateral 20 Hz stimulation, in situ hybridization revealed increased neurocan mRNA in glial fibrillary acidic protein (GFAP)‐positive astrocytes bilaterally in all hippocampal subfields. These changes were quantified in the dentate molecular layer, the termination zone of the perforant pathway, using laser microdissection in combination with quantitative reverse transcription‐polymerase chain reaction (RT‐PCR). Immediately after 24 h stimulation, a six‐fold upregulation was detected, which returned to control levels by 3 days post‐stimulation. Neurocan immunoreactivity was similarly upregulated bilaterally. Immunostaining intensity reached a maximum by 4 days and returned to control levels by 14 days. The pattern of neurocan expression in the hippocampus depended on the intensity and duration of electrical stimulation. Under conditions of less intense afferent stimulation (4–24 h of2.0 Hz paired‐pulse stimulation, interpulse interval 40 ms), increases in neurocan mRNA and immunoreactivity were restricted to the ipsilateral termination zone of the stimulated perforant pathway. This layer‐specific neurocan upregulation was not affected by intraperitoneal application of the NMDA‐receptor antagonist MK‐801. In conclusion, our data indicate that synaptic activity regulates the astrocytic expression of neurocan in a graded manner. © 2006 Wiley‐Liss, Inc.
A new method for measuring ice adhesion strength at an ice–substrate interface
Authors: Javan‐Mashmool M. , Volat C. , Farzaneh M.
Published: February 2006

This research focuses on the development of a direct technique for measuring atmospheric ice adhesion strength using embedded piezoelectric film sensors at the ice‐substrate interface. The substrate is a small aluminium beam on which PVDF piezoelectric sensors are bonded. The composite beam formed by aluminium and an ice layer is submitted to sinusoidal stress at the interface by a shaker on which one end of the beam is clamped. The piezoelectric charge coefficient is used to predict the electric charge density induced on the piezoelectric film, which enables us to develop a macroscopic and direct measurement technique for determining mechanical stresses at the atmospheric‐ice‐substrate interface. The preliminary results obtained show that adhesive failure was obtained for each test for a frequency close to the natural resonance frequency of the aluminium beam. Within the limitations of the experimental conditions, it was possible using this approach to obtain ice adhesion strengths in accordance with those obtained in the literature. This demonstrates the feasibility of this simple ice adhesion testing method. Copyright © 2006 John Wiley & Sons, Ltd.
Minor and trace elements as indicators of solute provenance and flow routing in a subglacial hydrological system
Authors: Mitchell Andrew C. , Brown Giles H. , Fuge Ron
Published: February 2006

The utility of minor and trace elements for subglacial solute‐provenance and hydrological flow‐routing studies is investigated at Haut Glacier d'Arolla (HGA), Switzerland. Principal component analysis (PCA) applied to the bulk meltwater chemistry indicates the concentration of most major ions, and some minor and trace elements (Sr, Mo, Ti) are inversely related to bulk meltwater discharge and have a clear hydrological control. Conversely, many other minor and trace elements have no clear relationship with meltwater discharge. This suggests that such solutes are affected by physico‐chemical controls such as sorption, (oxy)hydroxide formation and co‐precipitation reactions, in addition to any simple hydrological influence. PCA applied to rock digests and water‐rock interaction experiments indicates the complexity of determining the lithogenic source of minor and trace elements from subglacial chemical weathering processes. This reflects the complex aqueous mobility of many minor and trace elements and the heterogeneous geology of the HGA catchment. However, the study suggests that there is potential in minor and trace elements for solute‐provenance and flow‐routing studies in glacierized catchments underlain by a more homogeneous geology. Copyright © 2006 John Wiley & Sons, Ltd.
Accuracy assessment of MODIS daily snow albedo retrievals with in situ measurements in Karasu basin, Turkey
Authors: Tekeli Ahmet Emre , Şensoy Aynur , Şorman Arda , Akyürek Zuhal , Şorman Ünal
Published: February 2006

Over the ablation period of 2004, daily snow albedo values retrieved from the moderate‐resolution imaging spectroradiometer (MODIS) Terra were compared with ground‐based albedo measurements. Two data sets are used for this study. The first data set is from two automatic weather stations (AWS) located at fixed points in Karasu basin in eastern Turkey. This provided the temporal assessment of MODIS daily snow albedo values. The second data set, consisting of 19 observation points randomly distributed around one of the AWS sites, enables the spatial variability assessment of MODIS albedo retrievals. Both MODIS and in situ albedo observations were aggregated in a geographic information system for further analysis.

Generally, MODIS albedo values were within 10% of the in situ values. Reductions in albedo values were observed both in MODIS and field observations as snow depth decreased and snow water equivalent increased. Copyright © 2006 John Wiley & Sons, Ltd.
Instantaneous daytime conductive heat flow through snow on lake ice in Alaska
Authors: Jeffries Martin O. , Morris Kim
Published: February 2006

The instantaneous daytime conductive heat flow through the snow on lake ice was derived from snow depth, temperature and density measurements made during the course of six winters at MST Pond in central Alaska. The MST Pond data for winter 2003–04 are compared with results for the same period at six other sites (Barrow, Nome, Amos Lakes, Fairbanks, Wasilla, Seward) in Alaska. The maximum heat flow at MST Pond has varied between −19·5 and −8·8 W m−2. Each winter, the heat flow decreases as the total thickness of snow and ice increases with time. Superimposed on this trend are variations due to fluctuating air temperatures. The comparison of the MST Pond data with the other locations in Alaska reveals heat flow differences that reflect different weather conditions, particularly air temperature and wind, and the latter's effect on snow depth and density. Notwithstanding the regional differences, the heat flow values are of the same order of magnitude as those obtained for sea ice in the Arctic and Antarctica. The implications for the total winter conductive heat loss at large lakes and for regions where many small lakes cover a large proportion of the land are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Snowmelt runoff processes in a headwater lake and its catchment, subarctic Canadian Shield
Authors: Mielko Corrinne , Woo Ming‐ko
Published: February 2006

During the snowmelt season, surface runoff into northern Canadian Shield lakes is governed by the distribution of snow and its ablation, storage in catchment slopes and valleys, and flow delivery from uplands, bottomlands and from upper lakes. For the lake studied, time lags exist between the commencement of snowmelt and the arrival of runoff to the lake, with evaporation from the uplands and bottomlands consuming some of the meltwater produced. Inflow from an upper lake is delayed. With all these inputs, the lake becomes flooded, first forming a moat, followed by an expansion of the open water areas, which are subject to evaporation loss. Lake outflow begins when water level rises above the outlet threshold. For the snowmelt season, outflow constitutes 40% of total melt and rainfall. The lake itself is a major storage that continues to maintain outflow until the lake level drops below the threshold in early summer, after which flow ceases. Snowmelt is the main period when runoff is generated from the headwater catchment to replenish storage depleted in the previous summer, and to produce flow along the Shield valley that contains a chain of lakes. Copyright © 2006 John Wiley & Sons, Ltd.
Blowing snow studies in the Canadian Arctic Shelf Exchange Study, 2003–04
Authors: Savelyev S. A. , Gordon M. , Hanesiak J. , Papakyriakou T. , Taylor P. A.
Published: February 2006

Between mid January and early May 2004, during the Canadian Arctic Shelf Exchange Study 2003–04 expedition, we conducted a field project in which we deployed blowing‐snow particle counters, visibility sensors, a FlowCapt device, snow bags, an electric field meter and other instruments related to the observation of drifting and blowing snow on first‐year ice in Franklin Bay, Northwest Territories, Canada. Average snow depth was 7 cm at the beginning of the campaign and increased to 17 cm towards the end. Snow density in the first 8 cm of snow cover varied from 80 to 450 g m−3, with a median value of 240 g m−3. Basic results will be presented that relate particle counter profiles, wind speed and other data to visibility. We discuss threshold conditions for blowing snow, heat and water vapour fluxes and the electric field. Relative humidity with respect to ice was generally greater than 95% and sublimation rates are believed to have been low. Copyright © 2006 John Wiley & Sons, Ltd.
Measurement sampling and scaling for deep montane snow depth data
Authors: Fassnacht S. R. , Deems J. S.
Published: February 2006

The resolution of snow depth measurements was scaled from a nominal horizontal resolution of approximately 1·5 m to 3, 5, 10, 20, and 30 m using averaging (AVG) and resampling with a uniform random stratified sampling (RSS) scheme. The raw snow depth values were computed from airborne light detection and ranging data by differencing summer elevation measurements from winter snow surface elevations. Three montane study sites from the NASA Cold Lands Processes Experiment, each covering an 1100 m × 1100 m area, were used.

To examine scaling, log–log semi‐variograms with 50 log‐width bins were created for both of the different subsetting methods, i.e. RSS and AVG. From the raw data, a scale break, going from a structured to a nearly spatially random system, was observed in each of the log–log variograms. For each site, the scale break was still detectable at slightly greater than the resampling resolution for the RSS scheme, but at approximately twice the subsetting resolution for the AVG scheme. The resolution required to identify the scale break was still from 5 to 10 m, depending upon the location and sampling method. Copyright © 2006 John Wiley & Sons, Ltd.
Solar power for an Antarctic rover
Authors: Lever J. H. , Ray L. R. , Streeter A. , Price A.
Published: February 2006

Sensors mounted on mobile robots could serve a variety of science missions in Antarctica. Although weather conditions can be harsh, Antarctic snowfields offer unique conditions to facilitate long‐distance robot deployment: the absence of obstacles, firm snow with high albedo, and 24 h sunlight during the summer. We have developed a four‐wheel‐drive, solar‐powered rover that capitalizes on these advantages. Analyses and field measurements confirm that solar power reflected from Antarctic snow contributes 30–40% of the power available to a robot consisting of a five‐side box of solar panels. Mobility analyses indicate that the 80 kg rover can move at 0·8 m s−1 during clear sky conditions on firm snow into a 5 m s−1 headwind, twice the speed needed to achieve the design target of 500 km in 2 weeks. Local winter tests of the chassis demonstrated good grade‐climbing ability and lower than predicted rolling resistance. Tests of the completed robot occurred in Greenland in 2005. Copyright © 2006 John Wiley & Sons, Ltd.
Boundary‐layer growth over snow and soil patches: field observations
Authors: Granger Raoul J. , Essery Richard , Pomeroy John W.
Published: February 2006

Much of the snowmelt season is characterized by a patchy surface; differential heating of the snow and snow‐free surfaces results in a significant horizontal transport of energy that affects and contributes to the snowmelt. The calculation of the rate of energy advection requires some knowledge of the behaviour of the thermal boundary layer over the patches of snow and snow‐free surfaces. We present the results from a series of field observations of the rate of growth of the thermal boundary layer over snow and snow‐free patches. The results confirm that the boundary‐layer growth can be described by a power function of the distance from the leading edge of the patch. For the case of the thermal boundary layer over a snow patch within a bare field, the boundary‐layer growth is affected by the upwind surface roughness; the thermal boundary layer over a snow patch within a ‘rough’ field grows much more quickly than that in a ‘smooth’ field. Relationships are derived and presented for the parameterization of the boundary‐layer growth as a function of distance and upwind surface roughness. Copyright © 2006 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
Shrub tundra snowmelt
Authors: Pomeroy J. W. , Bewley D. S. , Essery R. L. H. , Hedstrom N. R. , Link T. , Granger R. J. , Sicart J. E. , Ellis C. R. , Janowicz J. R.
Published: February 2006

Observations of land surface and snowpack energetics and mass fluxes were made over arctic shrub tundra of varying canopy height and density using radiometers, eddy covariance flux measurements, and snow mass changes from snow surveys of depth and density. Over several years, snow accumulation in the shrubs was found to be consistently higher than in sparse tundra due to greater retention of snowfall by all shrubs and wind redistribution of snowfall to tall shrubs. Where snow accumulation was highest due to snow redistribution, shrubs often became buried by the end of winter. Three classes of shrub‐snow interactions were observed: tall shrubs that were exposed over snow, tall shrubs that were bent over and buried by snow, and short shrubs buried by snow. Tall shrubs buried by snow underwent ‘spring‐up’ during melt. Though spring‐up was episodic for a single shrub, over an area it was a progressive emergence from early to mid melt of vegetation that dramatically altered the radiative and aerodynamic properties of the surface. Short shrubs were exposed more rapidly once snow depth declined below shrub height, usually near the end of melt. Net radiation increased with increasing shrub due to the decreased reflectance of shortwave radiation overwhelming the increased longwave emission from relatively warm and dark shrubs. Net radiation to snow under shrubs was much smaller than that over shrubs, but was greater than that to snow with minimal shrub exposure, in this case the difference was due to downward longwave radiation from the canopy exceeding the effect of attenuated shortwave transmission through the canopy. Because of reduced turbulent transfer under shrub canopies and minimal water vapour contributions from the bare shrub branches, sublimation fluxes declined with increasing shrub exposure. In contrast, sensible heat fluxes to the shrub surface became more negative and those to the underlying snow surface more positive with increasing shrub exposure, because of relatively warm shrub branches, particularly on clear days. From well‐exposed tall shrubs, both a large upward sensible heat flow from shrub to atmosphere and a downward flow that contributed substantially to snowmelt were detected. As a result of radiative and turbulent transfer in shrub canopies, melt rates increased with shrub exposure. However, shrub exposure was not a simple function of shrub height or presence, and the transition to shrub‐exposed landscape depended on initial snow depth, shrub height, shrub species and cumulative melt, and this in turn controlled the melt energetics for a particular site. As a result of these complex interactions, observations over several years showed that snowmelt rates were generally, but not always, enhanced under shrub canopies in comparison with sparsely vegetated tundra. Copyright © 2006 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.