bluuebunny/crossref_metadata_2025 huggingface dataset:
Some Comments On the Concept of Thermal Forcing
Authors: Shutts G. J.
Published: July 2010

Arguments are given to support the notion that the thermally‐forced component of large‐scale motion is not simply that associated with pre‐specified diabatic heat sources as expressed in the classical models of thermal forcing. the concept of thermal equilibration, as an idealized response in models with a Newtonian diabatic heating process, is introduced and is argued to be relevant to real and numerically simulated atmospheric circulation. Equilibration is possible when Newtonian forcing is compatible with a nonlinear free mode flow pattern. the general question of the possible importance of equilibration and nonlinear free mode structures in the atmosphere is raised.
Tropical‐wide teleconnection and oscillation. I: Teleconnection indices and type I/type II states
Authors: Navarra A. , Ward M. N. , Miyakoda K.
Published: July 2010

The tropical oscillation of the ENSO‐monsoon (El Niño Southern Oscillation‐Asian monsoons) system is studied based on 34‐year simulations of an atmospheric general‐circulation model with specified sea surface temperature (SST), together with some observed data for the same period. In particular, two indices are studied: the first is the generalized index of Indian monsoon rainfall (IMR), and the other is an index by which the interaction/non‐interaction between the ENSO and the Indian monsoon system is assessed.

In order to examine the validity of the first index, the Indian subcontinent and the near‐equatorial western Pacific were selected as two key locations. They correspond, approximately, to the dominant regions in the first empirical orthogonal function of precipitation, for boreal summer and winter, respectively. These two regions form the western rim of a ‘horseshoe’ teleconnection pattern in their respective seasons. the time coefficients of empirical orthogonal function mode 1 in the two seasons are taken as the key indices which are referred to as the Tropical‐wide Oscillation Index (TOI).

Having defined the spatial patterns in both seasons, the lead‐lag teleconnection structure associated with the ENSO‐monsoon system is studied; the result is that the TOI for boreal summer is more useful than the TOI for boreal winter for identifying the lead‐lag nature of the ENSO‐monsoon. the new index is then related to traditional indices like the IMR and the Southern Oscillation Index, but proves to be a more comprehensive index for lead‐lag correlations with key variables, while the latter, the TOI for winter, has no precursory signal for the Indian monsoon for the following summer.

The second index is the Walker circulation Index (WAI), which represents the eastward/westward shift of the updraught region of the Walker circulation. It is proposed that the WAI can usefully distinguish between years when the ENSO‐monsoon oscillation operates (type I) and years when it does not (type II). If the SST in the key region has a climatologically close‐to‐normal condition, the state of the coupled equatorial system is in type II. On the other hand, if the deviation from climatology is large, the tropical‐wide oscillation will continue to be active; these years are type I. Elimination of the type II years from the data significantly enhances the time‐lagged correlations between the TOI and some key variables, such as SST. As a result, the biennial oscillation becomes clearer.
Analysis of the CEPEX ozone data using a 3D chemistry‐meteorology model
Authors: Lawrence Mark G. , Crutzen Paul J. , Rasch Philip J.
Published: July 2010

The ozone (O3) data collected during the Central Equatorial Pacific Experiment (CEPEX) are analysed with the aid of the 3D global photochemistry model MATCH‐MPIC (Model of Atmospheric Transport and Chemistry‐Max‐Planck‐Institute for Chemistry version). This study focuses on using MATCH‐MPIC to address three specific questions: (1) are the individual CEPEX O3 soundings, in particular the extremely low O3 levels occasionally observed in the upper troposphere (UT), reproducible by a state‐of‐the‐art global photochemical model driven with analysed meteorological data from the same time period as the measurements (March 1993): (2) are the CEPEX O3 data likely to be representative of the mean state of the regional atmosphere, or do they instead indicate the degree of variability in this region of the atmosphere; and (3) what causes the UT O3 minima? It is found that MATCH‐MPIC is not able to reproduce the soundings obtained during CEPEX on an individual basis; however, the model does reproduce some of the key features present in the observations, such as UT minima and mid‐tropospheric maxima similar to those observed during CEPEX. the UT O3 minima computed by the model are mainly due to convective pumping of low‐O3 marine boundary‐layer air, as is demonstrated by comparison with the results of a run in which convective transport of O3 is suppressed. the UT O3 minima simulated by MATCH‐MPIC (with O3 between 5 and 10 nmol mol‐1) are less intense than those observed (with O3 < 5 nmol mol‐1), even at relatively high model spatial and temporal resolution, and with a convection scheme that would be expected to readily produce UT O3 minima via intense pumping of low‐O3 marine boundary‐layer air directly into the UT convective outflow regions. This may indicate that additional photochemical loss processes are involved, either in situ in the UT or, in particular, near the surface in the convective inflow regions. where the model tends to overestimate the observed O3 levels. In addition, although a significant temporal variability for O3 in this region is computed, it is still less than indicated by the observations in the UT. This high degree of variability implies that individual O3 soundings will often differ considerably from the mean over a longer period. For instance, 20‐50% less O3 in the UT during the CEPEX period is computed with MATCH‐MPIC than the average for March. Thus, the CEPEX expedition was perhaps fortunate in encountering extreme conditions which produced extensive UT O3 minima. which have helped to demonstrate one end of the large degree of variability of O3 in the tropical troposphere.
A self‐sustaining climate mode in the tropical atlantic, 1995–97: Observations and modelling
Authors: Handoh Itsuki C. , Bigg Grant R.
Published: July 2010

An anomalous climatic event in the tropical Atlantic, starting in autumn 1995 and continuing into the autumn of 1997, is investigated. Using remotely sensed datasets and a reduced‐gravity model, it is shown that this event contained both a warm and a cold phase, each of roughly 12 months duration. The propagating signal within each phase is identified in the sea surface height and temperature signatures as both equatorial and off‐equatorial waves in the ocean, with coupling to atmospheric convection. The strength, geographical pattern and timing of the anomalous period is consistent with it being the first observed example of a coupled mode of interaction between the ocean and atmosphere found in two previous coupled ocean‐atmosphere models of the tropics. This interpretation means that the two‐phased climate event, which we will call the Equatorial Atlantic Oscillation (EAO), was associated with purely internal atmospheric and oceanographic variability within the Atlantic basin and hence was independent of the Pacific climate. It can also be inferred, from long‐term monthly sea surface temperature and sea‐level pressure datasets, that there were potentially several previous EAO events during the past century.
Review of atmospheric turbulence over cities
Authors: Roth M.
Published: July 2010

This paper provides a comprehensive, critical review of turbulence observations over cities. More than fifty studies are analysed with their experimental conditions summarized in an appendix. The main results are based on 14 high‐quality experiments which met criteria based on stringent experimental requirements. The observations are presented as non‐dimensional statistics to facilitate comparison between urban studies and work conducted over other rough, inhomogeneous surfaces. Wake production associated with bluff bodies, and the inhomogeneous distribution of sources and sinks of scalars, result in a roughness sub‐layer which for the studies reviewed extends to about 2.5 to 3 times the height of the buildings. It is shown that within this region the basis of several traditional micrometeorological approaches to describe the turbulent exchange is in doubt. There are strong similarities to flow over plant canopies, and many of the turbulence characteristics can be interpreted in the framework of a plane mixing layer. Future field observations should concentrate on the turbulent exchange near the top and within the urban canopy as well as within the urban boundary layer.
Linear instability of broad baroclinic zones
Authors: Juckes M. N.
Published: July 2010

Baroclinic energy conversions play a central role in mid‐latitude synoptic‐scale dynamics, drawing energy from the meridional temperature gradient and feeding it into the eddy dynamics. The physical mechanisms underlying these conversions can be investigated through the theory of small‐amplitude instabilities growing on a steady basic state. In a recent study the author analysed the instability associated with a boundary temperature transition concentrated in a narrow front. This paper looks at the complementary problem of a broad baroclinic zone. The solution is applicable both to the Eady model and to the Phillips two‐level quasi‐geostrophic model. The reduction in the growth rate relative to an infinitely broad, homogeneous baroclinic mne is inversely proportional to the width of the baroclinic zone, as found in previous studies. The constant of proportionality is expressed in a simplified and more general form, related to the derivative with respect to zonal wave number of the complex phase speed of the homogeneous problem. If the flow is purely baroclinic the maximum growth rate is reduced compared with that of a homogeneous, infinitely broad frontal zone by a factor 1 ‐ (2kmaxr)‐1. where kmax is the wave number of the most unstable mode of the homogeneous problem and r is the width of the baroclonic zone. The width, r, is defined in terms of the second meridional derivative of the boundary temperature gradient evaluated at the maximum of the latter. Results in the literature give consistent, though less general, expressions for the growth rate, but various predictions for the structure of the waves. The numerical solutions show that as the jet width is reduced a new type of mode appears in which critical lines at the lid (tropopause) play an important role.
Decay of a cut‐off low and contribution to stratosphere‐troposphere exchange
Authors: Gouget H. , Vaughan G. , Marenco A. , Smit H. G. J.
Published: July 2010

We present a case study of the decay of a cut‐off low over north‐west Europe in June 1996, to establish how the stratospheric air initially contained within it was transferred to the troposphere. Two mechanisms for stratosphere‐troposphere exchange are examined: direct convective erosion of the base of the low, and filamentation of the outer layers of the low along the flank of the polar jet stream. The approach taken relies on a combination of in‐situ ozone and humidity measurements by MOZAIC (Measurement of Ozone and water vapour by Airbus In‐service aircraft) aircraft and ozonesondes, and the European Centre for Medium‐Range Weather Forecasts analyses. MOZAIC ozone is used to choose two analyses eight days apart at the genesis (14 June 1996) and decay (22 June 1996) of the low which have a consistent ozone/potential‐vorticity relationship. Trajectories (both isentropic and three dimensional (3D)) between these two analyses reveal a consistent pattern; at the base of the low (310 K, 450 mb) all the trajectories attain tropospheric PV values whereas, at 320 K, those trajectories that leave the low experience a decrease in PV and those that do not leave the low retain their initial PV. We propose that air parcels leaving the low were stretched into thin filaments along the flank of the jet stream, which made them vulnerable to 3D mixing. A MOZAIC flight on 21 June 1996 provides direct evidence for this process.

Up to 22 June 1996 (by which time the low had lost its closed circulation) the satellite images showed very little convection beneath the corresponding PV anomaly. Mixing was only effective at the very base of the stratospheric air at 310 K. On 22 June the remaining remnant of high PV was advected into a region of deep convection over central and eastern Europe, mixing the remaining stratospheric air into the troposphere. Of the initial mass of 1015 kg of stratospheric air contained in the low, 6 × 1014 kg was stripped into filaments along the jet and 4 × 1014 kg remained to be mixed by convection during the period 22–23 June 1996.
The ECMWF operational implementation of four‐dimensional variational assimilation. I: Experimental results with simplified physics
Authors: Rabier F. , Järvinen H. , Klinker E. , Mahfouf J.‐F. , Simmons A.
Published: July 2010

This paper presents results of a comparison between four‐dimensional variational assimilation (4D‐Var). using a 6‐hour assimilation window and simplified physics during the minimization, and three‐dimensional variational assimilation (3D‐Var). Results have been obtained at ‘operational’ resolution T213L31/T63L31. (T defines the spectral triangular truncation and L the number of levels in the vertical, with the first parameters defining the resolution of the model trajectory, and the second the resolution of the inner‐loop.) The sensitivity of the 4D‐Var performance to different set‐ups is investigated. In particular, the performance of 4D‐Var in the Tropics revealed some sensitivity to the way the adiabatic nonlinear normal‐mode initialization of the increments was performed. Going from four outer‐loops to only one (as in 3D‐Var), together with a change to the 1997 formulation of the background constraint and an initialization of only the small scales, helped to improve the 4D‐Var performance. Tropical scores then became only marginally worse for 4D‐Var than for 3D‐Var. Twelve weeks of experimentation with the one outer‐loop 4D‐Var and the 1997 background formulation have been studied. The averaged scores show a small but consistent improvement in both hemispheres at all ranges. In the short range, each two‐ to three‐week period has been found to be slightly positive throughout the troposphere. The better short‐range performance of the 4D‐Var system is also shown by the fits of the background fields to the data. More results are presented for the Atlantic Ocean area during FASTEX (the Fronts and Atlantic Storm‐Track Experiment), during which 4D‐Var is found to perform better. In individual synoptic cases corresponding to interesting Intensive Observing Periods, 4D‐Var has a clear advantage over 3D‐Var during rapid cyclogeneses. The very short‐range forecasts used as backgrounds are much closer to the data over the Atlantic for 4D‐Var than for 3D‐Var. The 4D‐Var analyses also display more day‐to‐day variability. Some structure functions are illustrated in the 4D‐Var case for a height observation inserted at the beginning, in the middle or at the end of the assimilation window. The dynamical processes seem to be relevant, even with a short 6‐hour assimilation period, which explains the better overall performance of the 4D‐Var system.
The ecmwf operational implementation of four‐dimensional variational assimilation. III: Experimental results and diagnostics with operational configuration
Authors: Klinker E. , Rabier F. , Kelly G. , Mahfouf J.‐F.
Published: July 2010

The first two papers of this series describe the development of the operational four‐dimensional variational assimilation (4D‐Var) configuration implemented at the European Centre for Medium‐Range Weather Forecasts (ECMWF). The basic features are a 6‐hour incremental 4D‐Var set‐up with two minimization steps, using very simplified physics in the first minimization and a more complete set of linear physics in the second. This paper describes the validation of this configuration. Prior to implementation, 12 weeks of experimentation showed a consistent improvement relative to 3D‐Var. After an additional 6 weeks of encouraging parallel operation with the then current operational suite, 4D‐Var with physics was introduced in operations at ECMWF in November 1997. The difference in scores is statistically significant, and the fast‐growing components of the 4D‐Var analysis errors are shown to be smaller than their 3D‐Var counterparts. The performance of this new operational assimilation system is studied for the month of January 1998, for which the 4D‐Var analyses exhibit more realistic baroclinic waves than the 3D‐Var, especially in the Pacific area. A case‐study illustrates the improvement one can expect in forecast terms in the mid latitudes. The 4D‐Var system improved the forecast skill in the Tropics in general. Observing‐system experiments show that the current 4D‐Var operational system benefits from the assimilation both of satellite data and conventional observations.
Biosphere‐atmosphere interactions over West Africa. I: Development and validation of a coupled dynamic model
Authors: Wang Guiling , Eltahjr Elfatm A. B.
Published: July 2010

In this study we develop a zonally symmetric, synchronously coupled biosphere‐atmosphere model including ecosystem dynamics, and apply this model to study biosphere‐atmosphere interactions in the region of West Africa. The atmospheric model is zonally symmetric, and includes representation of atmospheric dynamics, a radiation scheme, a moist convection scheme, a boundary‐layer scheme, and a cloud‐parametrization scheme. The biospheric model is the Integrated BIosphere Simulator (IBIS), which includes representation of the water, energy, momentum, and carbon balance, vegetation phenology, and vegetation dynamics. We modified the representation of canopy hydrology in IBIS to account for the impact of rainfall subgrid variability. The biospheric model and atmospheric model are separately tested against observations. The synchronously coupled model is then used to simulate the biosphere‐atmosphere system of West Africa. A study on the role of biosphere‐atmosphere interactions, including ecosystem dynamics, in the climate variability over West Africa using this model will be presented in a companion paper.
An error analysis of radiance and suboptimal retrieval assimilation
Authors: Joiner J. , Dee D. P.
Published: July 2010

One of the outstanding problems in data assimilation has been, and continues to be, how best to utilize satellite data while balancing the trade‐off between accuracy and computational cost. A number of weather‐prediction centres have recently achieved remarkable success in improving their forecast skill by changing the method in which satellite data are assimilated into the forecast model from the traditional approach of assimilating retrieved products to the direct assimilation of radiances in a variational framework. Although there are. clear theoretical advantages to the direct radiance‐assimilation approach, it is not obvious at all to what extent the improvements that have been obtained so far can be attributed to the change in methodology or to various technical aspects of the implementation.

The central question we address here is: how much improvement can we expect from assimilating radiances rather than retrievals, all other things being equal? We compare the two approaches in a simplified theoretical framework. Direct radiance analysis is optimal in this idealized context, while the traditional method of assimilating retrievals is suboptimal because it ignores the cross‐covariances between background errors and retrieval errors. We show that interactive retrieval analysis (where the same background used for assimilation is also used in the retrieval step) is equivalent to direct assimilation of radiances with suboptimal analysis weights.

We illustrate and extend these theoretical arguments with several one‐dimensional analysis experiments, where we estimate vertical atmospheric profiles using simulated data from temperature sounding channels of both the High‐resolution InfraRed Sounder 2 (HIRS2) and the future Atmospheric InfraRed Sounder (AIRS). In the case of non‐interactive retrievals the results depend very much on the quality of the background information used for the retrieval step. In all cases, the impact of the choice of analysis method is dwarfed by the effect of changing some of the experimental parameters that control the simulated error characteristics of the data and the retrieval background.
The great fireball of 1934, October 11, and an instance of streak‐drift
Authors: King A. , Whipple F. J. W.
Published: July 2010

The fireball, probably brighter than the full moon, first appeared over E. Yorkshire at a height of 94 miles and ended, after a flight of 58 miles, over N. Lincolnshire at a height of 51 miles. The speed mas 21 miles per sec. and the radiant at ∞, 252°‐3, 8, +750°8. The parabolic orbit deduced from the corrected radiant gave rise to the suspicion that the object may have been connected with Comet Giacobini‐Zinner.

A streak was left along the track between the heights of 77 miles and 56 miles. The upper portion quickly vanished, and the part from 69 miles high to the and (56 miles high) drifted in B generally N.E. direction with rates as under for the respective heights :‐

Height. Speed of drift.

mls. mls. per hr.

69… … … 130

60 1/3 … … … 162

56 … … … 150
The lunar atmospheric tide in the Azores, 1894‐1932
Authors: Chapman S.
Published: July 2010

The lunar atmospheric tide is determined at two stations in the Azores, namely, Ponta Delgada (38° N., 26° W.) and Santa Cruz (39° N., 31° W.), from 39 to 26 years' bi‐hourly data (all days) for the barometric pressure. The mean results are respectively 22 sin (2t + 55 °) and 18 sin (2t + 58°) in microbars, so that high tide occurs 72 and 65 (solar) minutes after lunar transit. As at most other stations, the tide is distinctly later near the December solstice than at other times. The probable errors of these mean results are 1.6 and 2.2 microbars.

The harmonic coefficients for the first four components of the solar diurnal variation are also given.
The climate of the northern pennines: The coldest part of England
Authors: Manley Gordon
Published: July 2010

The northern Pennine moorlands comprise the most consistently elevated and chilly part of England. Very few observations are available however as regard temperature, although an interesting record, showing great extremes, was maintained near Alston from 18b1886. Rainfall is better known; other climatic features of especial note include occasional peculiarly violent thunderstorms and the well‐known “helm wind.” The writer has established a station at which temperatures have been taken in a standard screen since early in 1932; this is at a keeper's cottage on the exposed moorland of Upper Teesdale just to the south‐east of Crossfell. The altitude (1,840 ft.) makes the station the highest at which a continuous record has been kept in England. In general, although mean temperatures differ by about 5°.5F., no more than might be expected, from a group of Northern lon.land stations, the maxima are decidedly lower (7°. o) while the minima are not so much lower (3°. 3); and the mean daily range of temperature on the uplands is less than that in the valleys. This is to be expected; but exceptional extremes occur on particular occasions which appear to be due to the position of the moorland basin in which the station lies. As a whole the figures confirm the prevailing impression of bleakness associated with a windy and damp upland and correspond well with rccords at sea level in Southern Iceland.
Using Virtual Peers to Guide Visual Attention During Learning
Authors: Moreno Roxana , Reislein Martin , Ozogul Gamze
Published: July 2010

This study tested the hypothesis that animated pedagogical agents (APAs) can effectively support students’ learning by signaling visual information in multiple-representation learning environments. Novice students learned about electrical circuit analysis with an agent-based instructional program that included circuit diagrams and the corresponding Cartesian graphs. For some students, attention to relevant parts of the display was guided by an animated arrow (A group) or the deictic movements of a pedagogical agent (P group). A control (C) group learned with no visual attention-guiding method. Group P outperformed groups C and A on a posttest and gave lower difficulty ratings than group C. The findings suggest that a promising function of APAs is to support students’ cognitive processing during learning.
The Roles of Animated Pedagogical Agents’ Presence and Nonverbal Communication in Multimedia Learning Environments
Authors: Frechette Casey , Moreno Roxana
Published: July 2010

We examined how the presence and nonverbal communication of an animated pedagogical agent affects students’ perceptions and learning. College students learned about astronomy either without an agent’s image or with an agent under one of the following conditions: a static agent (S), an agent with deictic movements (D), an agent with facial expressions (E), or an agent with both deictic movements and facial expressions (DE). Group S outperformed group E on a comprehension test, but no other differences were found on students’ learning or perceptions. The results show that the presence of the studied agent – regardless of nonverbal abilities – did not produce at least a moderate effect size. Further, a static version of the agent was preferable to one with only facial expressions.
Formation of nitrogenated organic aerosols in the Titan upper atmosphere
Authors: Imanaka Hiroshi , Smith Mark A.
Published: July 2010

Many aspects of the nitrogen fixation process by photochemistry in the Titan atmosphere are not fully understood. The recent Cassini mission revealed organic aerosol formation in the upper atmosphere of Titan. It is not clear, however, how much and by what mechanism nitrogen is incorporated in Titan’s organic aerosols. Using tunable synchrotron radiation at the Advanced Light Source, we demonstrate the first evidence of nitrogenated organic aerosol production by extreme ultraviolet–vacuum ultraviolet irradiation of a N
2
/CH
4
gas mixture. The ultrahigh-mass-resolution study with laser desorption ionization-Fourier transform-ion cyclotron resonance mass spectrometry of N
2
/CH
4
photolytic solid products at 60 and 82.5 nm indicates the predominance of highly nitrogenated compounds. The distinct nitrogen incorporations at the elemental abundances of H
2
C
2
N and HCN, respectively, are suggestive of important roles of H
2
C
2
N/HCCN and HCN/CN in their formation. The efficient formation of unsaturated hydrocarbons is observed in the gas phase without abundant nitrogenated neutrals at 60 nm, and this is confirmed by separately using
13
C and
15
N isotopically labeled initial gas mixtures. These observations strongly suggest a heterogeneous incorporation mechanism via short lived nitrogenated reactive species, such as HCCN radical, for nitrogenated organic aerosol formation, and imply that substantial amounts of nitrogen is fixed as organic macromolecular aerosols in Titan’s atmosphere.
Important roles of PI3Kγ in osteoclastogenesis and bone homeostasis
Authors: Kang Heeseog , Chang Woochul , Hurley Marja , Vignery Agnès , Wu Dianqing
Published: July 2010

G protein-coupled receptor-regulated PI3Kγ is abundantly expressed in myeloid cells and has been implicated as a promising drug target to treat various inflammatory diseases. However, its role in bone homeostasis has not been investigated, despite the fact that osteoclasts are derived from myeloid lineage. We therefore carried out thorough bone phenotypic characterization of a PI3Kγ-deficient mouse line and found that PI3Kγ-deficient mice had high bone mass. Our analyses further revealed that PI3Kγ deficiency did not affect bone formation because no significant changes in osteoblast number and bone formation rate were observed. Instead, the lack of PI3Kγ was associated with decreased bone resorption, as evidenced by decreased osteoclast number in vivo and impaired osteoclast formation in vitro. The decreased osteoclast formation was accompanied by down-regulated expression of osteoclastogenic genes, compromised chemokine receptor signaling, and an increase in apoptosis during osteoclast differentiation. Together, these data suggest that PI3Kγ regulates bone homeostasis by modulating osteoclastogenesis. Our study also suggests that inhibition of PI3Kγ, which is being considered as a potential therapeutic strategy for treating chronic inflammatory disorders, may result in an increase in bone mass.
Detailed structural and assembly model of the type II secretion pilus from sparse data
Authors: Campos Manuel , Nilges Michaël , Cisneros David A. , Francetic Olivera
Published: July 2010

Many Gram-negative bacteria secrete specific proteins via the type II secretion systems (T2SS). These complex machineries share with the related archaeal flagella and type IV pilus (T4P) biogenesis systems the ability to assemble thin, flexible filaments composed of small, initially inner membrane-localized proteins called “pilins.” In the T2SS from
Klebsiella oxytoca
, periplasmic pseudopili that are essential for pullulanase (PulA) secretion extend beyond the bacterial surface and form pili when the major pilin PulG is overproduced. Here, we describe the detailed, experimentally validated structure of the PulG pilus generated from crystallographic and electron microscopy data by a molecular modeling approach. Two intermolecular salt bridges crucial for function were demonstrated using single and complementary charge inversions. Double-cysteine substitutions in the transmembrane segment of PulG led to position-specific cross-linking of protomers in assembled pili. These biochemical data provided information on residue distances in the filament that were used to derive a refined model of the T2SS pilus at pseudoatomic resolution. PulG is organized as a right-handed helix of subunits, consistent with protomer organization in gonococcal T4P. The conserved character of residues involved in key hydrophobic and electrostatic interactions within the major pseudopilin family supports the general relevance of this model for T2SS pseudopilus structure.
Finite-temperature critical point of a glass transition
Authors: Elmatad Yael S. , Jack Robert L. , Chandler David , Garrahan Juan P.
Published: July 2010

We generalize the simplest kinetically constrained model of a glass-forming liquid by softening kinetic constraints, allowing them to be violated with a small rate. We demonstrate that this model supports a first-order dynamical (space–time) phase transition between active (fluid) and inactive (glass) phases. The first-order phase boundary in this softened model ends in a finite-temperature dynamical critical point, which may be present in natural systems. In this case, the glass phase has a very large but finite relaxation time. We discuss links between the dynamical critical point and quantum phase transitions, showing that dynamical phase transitions in
d
dimensions map to quantum transitions in the same dimension, and hence to classical thermodynamic phase transitions in
d
 + 1 dimensions.
The effectiveness of workplace counselling: A systematic review
Authors: McLeod John
Published: July 2010

Background: In response to the stresses of the contemporary workplace, the challenges of maintaining satisfactory work‐life balance, and the costs to business of employee mental health problems, many organisations have contracted to make counselling services available to their staff. It is essential to evaluate the effectiveness of workplace counselling, in order to maintain standards, and to identify examples of good practice. Objectives: This paper presents a comprehensive, systematic review of the effectiveness of workplace counselling. Findings are analysed in terms of client satisfaction, psychological functioning, the meaning of work, work behaviour, and negative outcomes. Findings: Taken as a whole, the results of research suggest that counselling is generally effective in alleviating psychological problems, has a significant impact on sickness absence, and has a moderate effect on attitudes to work. Discussion: Methodological issues are discussed, and it is recommended that more high‐quality research is required in order to reinforce the evidence base for workplace counselling in relation to a number of key questions.
What difference does counselling make? – The perceptions of drug‐using clients on low incomes
Authors: Edwards Jane , Loeb Sarah
Published: July 2010

Context: This paper reports on a qualitative study looking at the perceptions of clients who use drugs and are on low income. Research suggests that counselling services can experience difficulties in reaching and retaining such clients, and outcomes of counselling can be disappointing. Aim: To learn from clients who had engaged in counselling for over six months what difference it had made to their lives. Method: Grounded theory methodology was used to analyse semi‐structured interviews with six participants. Findings: Findings included changes in the clients’ internal world, their connectedness with society, their familiarity with counselling, and their perception of the relationship with the counsellor. Factors within the counselling process which helped and hindered change were identified. The study documents how participants were able to use counselling to improve their lives.
In defense of the reference: more than linking in evolving Web environments
Authors: ANDERSON‐WILK Mark
Published: July 2010

Even in today's intensively hyperlinked environment, full bibliographic citations continue to serve the important functions of attribution, accountability, and conversation that are at the heart of scholarly publishing. However, the long‐running tradition of citation documentation is being increasingly eroded and challenged by new Web technologies and practices. This paper discusses the implications of scholarly publishing reference practices in the rapidly evolving medium of the Web. A model for greater separation of author‐documented citations and user‐centric linking is proposed.
Book Reviews
Authors: ALBITZ Becky
Published: July 2010

Content Licensing: Buying and Selling Digital Resources Michael Upshall Oxford, Chandos Publishing, 2009, 258 pp. ISBN 1 84334 333 9, ISBN‐13 978 1 84334 333 2; £47.00/US$80.00/€60.00; pbk
Book Reviews
Authors: CRAIG Iain D.
Published: July 2010

Measuring Academic Research: How to Undertake a Bibliometric Study Ana Andrés Chandos Publishing, 2009, 169 pp. ISBN 978 1 84334 528 2, £ 45.00, pbk
Effect of hatching date, vertical distribution, and interannual variation in physical forcing on northward displacement and temperature conditions of Norwegian spring-spawning herring larvae
Authors: Vikebø Frode B. , Husebø Åse , Slotte Aril , Stenevik Erling Kåre , Lien Vidar S.
Published: July 2010

Vikebø, F. B., Husebø, Å., Slotte, A., Stenevik, E. K., and Lien, V. S. 2010. Effect of hatching date, vertical distribution, and interannual variation in physical forcing on northward displacement and temperature conditions of Norwegian spring-spawning herring larvae. – ICES Journal of Marine Science, 67: 1948–1956. Early hatching has been shown to be associated with increased survival of Norwegian spring-spawning herring (Clupea harengus) larvae. We investigated whether the process behind this association is related to larval drift and ambient temperature. A three-dimensional hydrodynamic model was used to simulate the effect of hatching date on northward displacement and temperature conditions of larvae from spawning grounds off western Norway for 1989–2008. The simulations revealed that the displacement during a period of 60 d was greatest if the larvae hatched early in the season and if they were located near the surface. The relationship between drift speed and ambient temperature was significantly negative, but less so later in the season, because the coastal current became progressively warmer. Results from the simulated interannual variations in larval drift compared with the observed survival suggest that a rapid northward displacement to the main nursery area in the Barents Sea is more important for larval survival than ambient temperature. The significant effect of northward displacement on survival could be explained by reduced overlap with predators and/or higher prey densities, but the causal processes involved remain to be investigated.
Spanish otter trawl fisheries in the Cantabrian Sea
Authors: Punzón Antonio , Hernández Carmen , Abad Esther , Castro José , Pérez Nelida , Trujillo Valentín
Published: July 2010

Punzón, A., Hernández, C., Abad, E., Castro, J., Pérez, N., and Trujillo, V. 2010. Spanish otter trawl fisheries in the Cantabrian Sea. – ICES Journal of Marine Science 67: 1604–1616 A non-hierarchical classification technique (clustering large applications, CLARA) was used to identify four fishing tactics of Spanish otter trawlers in the Cantabrian Sea (ICES Division VIIIc) from 1983 to 2004: mixed fishing, blue whiting fishing, horse mackerel fishing, and mackerel fishing. There were no significant differences in the fishing tactics employed by two trawl fleets identified using a non-hierarchical classification technique (partition around medoids). There was, however, a decline in the use of the blue whiting fishing tactic from 2000 on, perhaps as a result of competition with pairtrawls, a gear whose main target species is blue whiting. There was an increase in the number of trips using the mackerel fishing tactic from 1996, a change possibly caused by improved market conditions. Between 2000 and 2004, the fleets had two distinct behaviour patterns, identified depending on the area in which they operated. The study area could therefore be subdivided into two areas based on the prevalence of the fishing tactic followed. The horse mackerel fishing tactic was more commonly used in the west, and the mixed fishing tactic in the east.
Paraperlucidibaca baekdonensis gen. nov., sp. nov., isolated from seawater
Authors: Oh Ki-Hoon , Lee Soo-Young , Lee Mi-Hwa , Oh Tae-Kwang , Yoon Jung-Hoon
Published: July 2010

A Gram-negative, non-spore-forming, rod-shaped bacterial strain, RL-2T, was isolated from seawater of the East Sea in Korea and was subjected to a polyphasic taxonomic study. Strain RL-2T grew optimally at pH 7.5–8.0, at 20 °C and in the absence of NaCl. Phylogenetic trees based on 16S rRNA gene sequence analysis showed that strain RL-2T forms a cluster with Perlucidibaca piscinae IMCC1704T and various uncultured and unidentified gammaproteobacteria. Strain RL-2T exhibited 16S rRNA gene sequence similarity values of 96.1 % to Perlucidibaca piscinae IMCC1704T and 93.7–99.7 % to the uncultured bacterial clones belonging to the cluster and an unidentified gammaproteobacterium. The fatty acid profile of strain RL-2T was similar to that of Perlucidibaca piscinae IMCC1704T, but the predominant ubiquinone type (Q-11) of strain RL-2T was different from that (Q-8) of Perlucidibaca piscinae IMCC1704T. The DNA G+C content of strain RL-2T was 61.3 mol%. On the basis of phylogenetic, chemotaxonomic and phenotypic data, strain RL-2T is considered to represent a novel species of a new genus in the family Moraxellaceae, for which the name Paraperlucidibaca baekdonensis gen. nov., sp. nov. is proposed. The type strain of Paraperlucidibaca baekdonensis is RL-2T ( = KCTC 23145T  = CCUG 59307T).
Agrococcus carbonis sp. nov., isolated from soil of a coal mine
Authors: Dhanjal Soniya , Kaur Ishwinder , Korpole Suresh , Schumann Peter , Cameotra Swaranjit Singh , Pukall Rüdiger , Klenk Hans-Peter , Mayilraj Shanmugam
Published: July 2010

An actinobacterial strain, designated G4T, isolated from a coal mine was subjected to polyphasic taxonomic characterization. Cells were Gram-stain-positive, yellow-pigmented, non-motile and non-spore-forming cocci. This organism possessed a type B peptidoglycan with diaminobutyric acid as diagnostic diamino acid. The major respiratory quinones were MK-9, MK-10 and MK-11. The major fatty acids were anteiso-C15 : 0 (41.6  %) and anteiso-C17 : 0 (32.8 %). The predominant cellular polar lipids were diphosphatidylglycerol and phosphatidylglycerol. Cell wall sugars comprised galactose, glucose, ribose and rhamnose. 16S rRNA gene sequence analysis of strain G4T showed high similarity with Agrococcus baldri (98.9 %), Agrococcus citreus (97.8 %), Agrococcus jenensis (97.3 %) and Agrococcus terreus (97.0 %). Sequence similarity with the type strains of the other species of the genus Agrococcus was less than 97.0 %. The DNA–DNA relatedness of strain G4T with the type strains of Agrococcus baldri, Agrococcus citreus, Agrococcus jenensis and Agrococcus terreus was less than 70 %. On the basis of the physiological, biochemical and chemotaxonomic characteristics, strain G4T should be classified as the type strain of a novel species of the genus Agrococcus, for which the name Agrococcus carbonis sp. nov. is proposed. The type strain is G4T ( = MTCC 10213T  = DSM 22965T).
Fragile regions and not functional constraints predominate in shaping gene organization in the genus Drosophila
Authors: von Grotthuss Marcin , Ashburner Michael , Ranz José M.
Published: July 2010

During evolution, gene repatterning across eukaryotic genomes is not uniform. Some genomic regions exhibit a gene organization conserved phylogenetically, while others are recurrently involved in chromosomal rearrangement, resulting in breakpoint reuse. Both gene order conservation and breakpoint reuse can result from the existence of functional constraints on where chromosomal breakpoints occur or from the existence of regions that are susceptible to breakage. The balance between these two mechanisms is still poorly understood. Drosophila species have very dynamic genomes and, therefore, can be very informative. We compared the gene organization of the main five chromosomal elements (Muller's elements A–E) of nine Drosophila species. Under a parsimonious evolutionary scenario, we estimate that 6116 breakpoints differentiate the gene orders of the species and that breakpoint reuse is associated with ∼80% of the orthologous landmarks. The comparison of the observed patterns of change in gene organization with those predicted under different simulated modes of evolution shows that fragile regions alone can explain the observed key patterns of Muller's element A (X chromosome) more often than for any other Muller's element. High levels of fragility plus constraints operating on ∼15% of the genome are sufficient to explain the observed patterns of change and conservation across species. The orthologous landmarks more likely to be under constraint exhibit both a remarkable internal functional heterogeneity and a lack of common functional themes with the exception of the presence of highly conserved noncoding elements. Fragile regions rather than functional constraints have been the main determinant of the evolution of the Drosophila chromosomes.
Effect of electroless process parameters for nickel‐phosphorous coatings on carbon fibres
Authors: Abdel Hamid Z. , Abdel Aal A.
Published: July 2010

Purpose

The purpose of this paper is to investigate the deposition of uniform, adherent and crack‐free Ni‐P thin films on carbon fibres using the electroless deposition technique.

Design/methodology/approach

Before applying the electroless process, the carbon fibre surfaces must be subjected to several treatment processes to remove the organic binder, etching and surface metallization. The surface morphology of the Ni‐P coatings was assessed using a scanning electron microscope (SEM). The chemical compositions of Ni‐P layers were identified by energy dispersive X‐ray analysis (EDS). The bond strength of the coated layer was determined by measuring the electrical resistance at the fibre/coating interface. The magnetic properties of the fibres were estimated using a hysteresis diagram. The tensile performance of single fibres coated by Ni‐P has been investigated with respect to coating thickness.

Findings

Pre‐treatment processes are used to improve the adhesion of Ni‐P layers and to obtain homogeneous coatings. The influence of plating parameters (temperature, pH and time) on the coating thickness of the Ni‐P layer was investigated. It was found that the coating thickness increased as the pH value, plating time and the temperature of the bath increased. The results revealed that a complete and uniform Ni‐P coating on fibre could be obtained at optimum conditions 85°C, pH 6, for 60 min, and the results indicated that the P content in the electroless deposit is approximately 3.4 wt%. The tensile strength values are improved significantly after coating and increased by 3‐5 times with increasing of coating thickness from 0.3 to 2 μm.

Originality/value

The results presented in this work are an insight into understanding of the deposition and adherence of Ni‐P thin films on carbon fibre using the electroless technique and behaviour of the coated fibre.
Corrosion of the heat‐affected zone of stainless steel weldments
Authors: Santillan S.N. , Valdez S.B. , Schorr W.M. , Martinez R.A. , Colton S.J.
Published: July 2010

Purpose

The purpose of this paper is to investigate the corrosion of the heat‐affected zone (HAZ) and weld zone of austenitic stainless steels that have been welded using two different processes. The corrosion behavior is evaluated in synthetic seawater using the electrochemical polarization technique.

Design/methodology/approach

Welded and unwelded UNS S30403 specimens were welded by flux core arc, and gas tungsten arc welding (GTAW) techniques. The test equipment consisted of an electrochemical three‐electrode cell using synthetic seawater as the corrosive medium. The scan rate was 10 mV/s and the potential range was −500‐500 mV vs saturated calomel electrode. The pH for the synthetic seawater was around seven. The electrochemical tests were performed after 1, 2, 3, and, 11 weeks. The metal surface was characterized by examination using an inverted microscope and scanning electron microscopy.

Findings

The polarization measurements of the flux core arc welding‐HAZ showed a high corrosion susceptibility, while GTAW‐HAZ presented good corrosion performance.

Practical implications

With the application and correct interpretation of this electrochemical technique, designers, welding engineers, and manufactures can access important information and take correct decisions regarding welding processes to meet corrosion resistance requirements.

Originality/value

The methodology and approach of interpreting the polarization plots used in this research can be applied to study other welding techniques and different welded metals in specific corrosive media, which will be of value to the welding industry.
Hidden parts in the history of the school library in Kuwait
Authors: Buabbas Hasan , Rezgui Yacine
Published: July 2010

Purpose

The purpose of this paper is to provide a clearer picture of the first establishment of school libraries in Kuwait. In addition, the paper explores the development of the school library between 1911 and 1962.

Design/methodology/approach

The paper adopts a qualitative research strategy. The interviews and documentation techniques have been utilized to gather data about the subject.

Findings

The findings traced the first appearance of the school library in Kuwait back to 1944. It showed that the development of the library encountered major difficulties.

Originality/value

The unique study reveals a branch of Kuwaiti education history hitherto concealed from its people, where the recognition of other disciplines in the field and the need for further study emerges.