bluuebunny/crossref_metadata_2025 huggingface dataset:
The consequences of non-starch polysaccharide solubility and inclusion level on the health and performance of weaned pigs challenged with enterotoxigenic Escherichia coli
Authors: Wellock I. J. , Fortomaris P. D. , Houdijk J. G. M. , Wiseman J. , Kyriazakis I.
Published: August 2007

The inclusion of insoluble NSP (iNSP) in weaner pig diets has been reported to decrease post-weaning colibacillosis (PWC). Conversely, soluble NSP (sNSP) have been shown to exacerbate PWC. The present study investigated the effect of NSP solubility and inclusion level on the health and performance of newly weaned pigs challenged with enterotoxigenic Escherichia coli (ETEC), using NSP sources known not to affect digesta viscosity, in a 2 ×  2 ×  2 factorial combination of NSP solubility (iNSP v. sNSP), inclusion level (low (L; 50 g/kg) v. high (H; 150 g/kg)) and ETEC challenge (infected v. sham). Infection had no effect on pig health, but reduced performance to a larger extent in pigs on the L diets compared with those on the H diets. The inclusion of sNSP significantly decreased the occurrence of diarrhoea (P < 0·001) and improved gut health, as indicated by a lower caecal digesta pH (P = 0·008) and increased (P = 0·002) Lactobacillus:coliform ratio, when compared with the iNSP diet on day 14 post-weaning. There was no effect of NSP solubility on ETEC shedding, digesta viscosity or pig performance. Pigs on the H diets had fewer cases of diarrhoea and shed fewer ETEC than those on the L diets. Increasing NSP inclusion significantly increased colonic Lactobacillus:coliform ratio, volatile fatty acid concentration and caecal digesta viscosity, but decreased performance. These results suggest that sNSP per se are not detrimental to pig health and that increasing the concentration of NSP in weaner diets that do not increase digesta viscosity may have a beneficial effect on gut health and protect against PWC.
RESISTING CONTROL OF NEGLECTED TROPICAL DISEASES: DILEMMAS IN THE MASS TREATMENT OF SCHISTOSOMIASIS AND SOIL-TRANSMITTED HELMINTHS IN NORTH-WEST UGANDA
Authors: PARKER MELISSA , ALLEN TIM , HASTINGS JULIE
Published: August 2007

A strong case has recently been made by academics and policymakers to develop national programmes for the integrated control of Africa’s ‘neglected tropical diseases’. Uganda was the first country to develop a programme for the integrated control of two of these diseases: schistosomiasis and soil-transmitted helminths. This paper discusses social responses to the programme in Panyimur, north-west Uganda. It shows that adults are increasingly rejecting free treatment. Resistance is attributed to a subjective fear of side-effects; divergence between biomedical and local understandings of schistosomiasis/bilharzia; as well as inappropriate and inadequate health education. In addition, the current procedures for distributing drugs at a district level are problematic. Additional research was carried out in neighbouring areas to explore the generalizability of findings. Comparable problems have arisen. It is concluded that the national programme will not fulfil its stated objectives of establishing a local demand for mass treatment unless it can establish more effective delivery strategies and promote behavioural change in socially appropriate ways. To do so will require new approaches to social, economic and political aspects of distribution. There are reasons why populations infected with the ‘neglected tropical diseases’ are themselves neglected. Those reasons cannot just be wished away.
MENARCHE AND FATHER ABSENCE IN A NATIONAL PROBABILITY SAMPLE
Authors: BOGAERT ANTHONY F.
Published: August 2007

The relation between women’s timing of menarche and father absence was examined in a national probability sample of Great Britain (NATSAL 2000; N>5000). Current body mass index (as a proxy for childhood weight) was examined as a potential mediator of this relationship, along with the potential moderating role that siblings (e.g. number of older brothers) had on this relationship. As in a number of previous studies, an absent father (but not an absent mother) during childhood predicted an earlier age of puberty (i.e. an early menarche). There was no evidence that weight mediated this relationship or that siblings moderated it. Both a lower body mass index and more siblings (e.g. more younger sisters and brothers) were independent predictors of a later timing of puberty. The results confirm that certain psychosocial factors (i.e. father absence; presence of siblings) may affect the timing of sexual maturation in adolescent girls.
PREVENTION AND TREATMENT PRACTICES AND IMPLICATIONS FOR MALARIA CONTROL IN MUKONO DISTRICT UGANDA
Authors: MBONYE A. K. , BYGBJERG I. C. , MAGNUSSEN P.
Published: August 2007

Available data in Uganda indicate a resurgence of malaria morbidity and mortality countrywide. This study assessed the burden of malaria, treatment and prevention practices in order initiate a policy debate on the scaling-up of current interventions. A triangulation of methods using a cross-sectional survey and key informant interviews was used to assess self-reported malaria at a household level in Mukono District, Uganda. A total of 5583 households were surveyed, and a high proportion (2897, 51·9%) reported a person with malaria two weeks prior to the survey. Only 546 households (9·8%) owned and used insecticide-treated nets (ITNs) for malaria prevention. Similarly, only a few households (86, 1·5%) used indoor residual spraying. Self-treatment with home-stocked drugs was high, yet there was low awareness of the effectiveness of expired drugs on malaria treatment. Self-reported malaria was associated with socioeconomic, behavioural and environmental factors, but more especially with household ownership of ITNs. These results will contribute to the current debate on identifying new approaches for scaling-up prevention interventions and effective case management, as well as selection of priority interventions for malaria control in Uganda.
Dynamics of droplet–film collision
Authors: PAN K. L. , LAW C. K.
Published: August 2007

The head-on collision of a droplet onto a liquid layer of the same material, backed bya solid surface, was experimentally and computationally investigated, with emphasis on the transition from bouncing of the droplet to its absorption by the film for given dropletWeber number, We, and the film thickness scaled by the droplet radius, Hf. Experimental results show that while absorption is favoured with increasing We, there exists a range around Hf ≈, 1 over which this tendency is moderated. This local moderation in turn corresponds to a regime, 11 ≲ We ≲ 14, over which increasing Hf from a small value leads to a triple reversalbehaviour of absorption, bouncing, absorption again, and bouncing again. The collision dynamics including evolution of the surface contours of the droplet and film, as well as the energy budgets, were then simulated by using a front-tracking technique. For collisionsleading to absorption and partial absorption, for which part of the absorbed droplet is subsequently ejected from the film, rupture and hence merging of the interfaces were manually imposed at an instant that leads to agreement between the subsequent calculated and experimental images. The simulation satisfactorily identified the different factors influencing the observed non-monotonic response of the collision event.
The intermediate Rossby number range and two-dimensional–three-dimensional transfers in rotating decaying homogeneous turbulence
Authors: BOUROUIBA LYDIA , BARTELLO PETER
Published: August 2007

Rotating homogeneous turbulence in a finite domain is studied using numerical simulations, with a particular emphasis on the interactions between the wave and zero-frequency modes. Numerical simulations of decaying homogeneous turbulence subject to a wide range ofbackground rotation rates are presented. The effect of rotation is examined in two finiteperiodic domains in order to test the effect of the size of the computational domain on the results obtained, thereby testing the accurate sampling of near-resonant interactions.We observe a non-monotonic tendency when Rossby number Ro is varied from large values to the small-Ro limit, which is robust to the change of domain size. Three rotation regimes are identified and discussed: the large-, the intermediate-, and the small-Ro regimes. The intermediate-Ro regime is characterized by a positive transfer of energy from wave modes to vortices. The three-dimensional to two-dimensional transfer reaches an initial maximum for Ro ≈ 0.2 and it is associated with a maximum skewness of vertical vorticity in favour of positive vortices. This maximum is also reached at Ro ≈ 0.2. In the intermediate range an overall reduction of vertical energy transfer is observed. Additional characteristic horizontal and vertical scales of this particular rotation regime are presented and discussed.
Instability of the buoyancy layer on an evenly heated vertical wall
Authors: McBAIN G. D. , ARMFIELD S. W. , DESRAYAUD GILLES
Published: August 2007

The stability of the buoyancy layer on a uniformly heated vertical wall in a stratified fluid is investigated using both semi-analytical and direct numerical methods. As in the related problem in which the excess temperature of the wall is specified, the basic laminar flow is steady and one-dimensional. Here flows varying in time and with height are considered, the behaviour being determined by the fluid's Prandtl number and a Reynolds number proportional to the ratio of two temperature gradients: the horizontal one imposed at the wall and the vertical one existing in the far field. For low Reynolds numbers, the flow is stable with variation only in the wall-normal direction. For Reynolds numbers greater than a critical value, depending on the Prandtl number, the flow is unstableand supports two-dimensional travelling waves. The critical Reynolds number and other properties have been obtained via linearized stability analysis and are shown to accuratelypredict the behaviour of the full nonlinear solution obtained numerically for Prandtl number 7. The stability analysis employs a novel Laguerre collocation scheme while the direct numerical simulations use a second-order finite volume method.
Direct numerical simulation of turbulent Taylor–Couette flow
Authors: DONG S.
Published: August 2007

We investigate the dynamical and statistical features of turbulent Taylor–Couette flow (for a radius ratio 0.5) through three-dimensional direct numerical simulations (DNS) at Reynolds numbers ranging from 1000 to 8000. We show that in three-dimensional space the Görtler vortices are randomly distributed in banded regions on the wall, concentrating at the outflow boundaries of Taylor vortex cells, which spread over the entirecylinder surface with increasing Reynolds number. Görtler vortices cause streaky structures that form herringbone-like patterns near the wall. For the Reynolds numbers studied here, the average axial spacing of the streaks is approximately 100 viscous wall units, and the average tilting angle ranges from 16° to 20°. Simulationresults have been compared to the experimental data in the literature, and the flow dynamics and statistics are discussed in detail.
Direct numerical simulations of transitional pulsatile flow through a constriction
Authors: BERATLIS N. , BALARAS E. , KIGER K.
Published: August 2007

A combined experimental and numerical study of transitional pulsatile flow through a planar constriction is presented. The parametric space that we adopt is similar to the one reported in a variety of past experiments relevant to the flow through stenosed arteries. In general, the flow just downstream of the constriction is dominated by the dynamic of the accelerating/decelerating jet that forms during each pulsatile cycle. We found a switch in the shedding frequency and roll-up dynamics, just after the flow rate approaches its maximum value in the cycle. The flow in the reattached area further downstream is also affected by the jet dynamics. A ‘synthetic’ turbulent-like wall-layer develops, an is constantly supported by streamwise vortices that originate from the spanwise instabilities of the large coherent structures generated by the jet. The relation of these structures to the phase-averaged turbulent statistics and the turbulent kinetic energy budgets is discussed.
Transient growth in vortices with axial flow
Authors: HEATON C. J. , PEAKE N.
Published: August 2007

We investigate transient growth in high-Reynolds-number vortices with axial flow. Manycases of vortex instability are not fully explained by strong exponential instability modes, and transient growth could offer an alternative route to breakdown in such cases. Strong transient growth is found, in agreement with previous studies. We first discuss the problem by reference to ducted vortices which model aeroengine flow. The transient growth is inviscid in character, and in this paper we specifically interpret it as an effect of the inviscid continuous spectrum. The relevant inviscid theory explains new scalings which we find for the transient growth, which are generalizations of the quadratic scaling seen previously in two-dimensional flows and non-swirling pipe flows. We then turn to a second case, of interest for vortex breakdown, the Batchelor vortex, and present calculations of the transient growth. Large growth is possible, especially for the helical modes (with azimuthal wavenumber |m| = 1). The general trends are complicated by a number ofissues, including a long-wavelength effect and a resonance effect, both of which were recently discovered for a vortex without axial flow and are found here to be present in the Batchelor vortex also. Overall, the results suggest that strong transient effects are present in the moderate- to high-swirl regime of practical interest (swirl number q ≳ 2). Foraxisymmetric (m = 0) and higher (|m| > 1) modes, however, transient effects are not found to be significant.
The formation and maintenance of a leading-edge vortex during the forward motion of an animal wing
Authors: MAXWORTHY T.
Published: August 2007

A simple model is presented to explain the observed generation of a quasi-steady vortex at the leading edge of an animal wing that rotates in a horizontal plane about a body-centred axis. Vorticity formed by separation at the leading edge is transported outwards by a spanwise velocity field generated by two sources of spanwise pressure gradient, one induced centrifugally and the other by variations in the vortex size and circulation. The vorticity is then deposited into a trailing vortex system that takes the form of a downward propagating vortex ring. This mechanism appears to apply generally to flying animals but is modelled here for those in hovering flight.
Receptive (aural) vocabulary development in children with permanent bilateral sensorineural hearing impairment
Authors: Kiese-Himmel C
Published: August 2007

Objective:

The receptive (aural) vocabulary development of children with binaural-aided residual hearing was investigated in a prospective longitudinal analysis (repeated measures).

Patient and methods:

Thirty-three children with sensorineural hearing loss, without major co-morbidities (mean age at the first testing point, 56.2 months, standard deviation 19.0 months) were recruited from the 1994 German Goettinger Hearing Language Register. Their receptive vocabulary was measured using standardised tests (with reference to normal hearing child performance) on three separate test points (mean follow up, 18.7 months, standard deviation 5.0 months).

Results:

On average, the study group scored below the normal range at the first and second tests and made a significant improvement at the last test. The degree of hearing loss was found to be significantly correlated to vocabulary performance at all time points, with increasing correlation coefficients. At the third test, significant predictive variables for successful receptive vocabulary outcome were found to be: degree of hearing loss (t = 5.43;p < 0.0001); age at diagnosis (t = 2.29;p = 0.03); and nonverbal intelligence (t = 2.82;p = 0.009).

Conclusion:

If permanent childhood hearing impairment is mild and/or is detected early, and if the child grows up in a monolingual environment, the development of receptive vocabulary within the normal range is possible.
Two Worlds of Necessity in ICSID Arbitration: CMS and LG&E
Authors: WAIBEL MICHAEL
Published: August 2007

Two recent ICSID cases, CMS v. Argentina and LG&E v. Argentina, diverge on the application of necessity under customary international law. The LG&E tribunal affirmed that Argentina's financial crisis amounted to a state of necessity. On virtually identical facts, CMS had reached the opposite conclusion 18 months earlier. This unhealthy split of opinion highlights the fact that necessity is ill-suited to financial crises. The state of necessity is at best a crude defence, appropriate as long as international law in this area remains underdeveloped. Lack of payment capacity will strike a better balance between host country and investor interests in future sovereign debt crises. This defence is also more amenable to adjudication by national courts and international tribunals.
‘No Topic Has Been the Subject of More Confusion’: Two Books on the Relationship between International Politics and Law
Authors: ROTHMAN MAARTEN
Published: August 2007

Jack L. Goldsmith and Eric A. Posner, The Limits of International Law, Oxford, Oxford University Press, 2005, ISBN-13: 9780195314175, ISBN-10: 0195314174, 272 pp., £11.99 (pb).

Thomas J. Schoenbaum, International Relations: The Path Not Taken. Using International Law to Promote World Peace and Security, Cambridge, Cambridge University Press,2006, ISBN-13: 9780521681506, ISBN-10: 0521681502, 320 pp., £16.99 (pb).
Suicide in Three Ethnic Groups in Huhhot, Inner Mongolia
Authors: Wang Ding , Wang Yu Ting , Wang Xue Ya
Published: August 2007

Suicide was examined in three ethnic groups in Huhhot, Inner Mongolia, for the period 1986-1991. The influence of the different cultures on suicide was studied. The Han have the most tolerant views toward suicide and were found also to have the highest suicide rate. The Hui follow Islam, which condemns suicide, and were found to have the lowest suicide rate. The Meng expect to suffer in life and are thus not prone to suicide, though as they move to the cities and become more educated, they tend to adopt Han cultural values so that their suicide rate is now moderately high.
Suicide and Meteorological Factors in Huhhot, Inner Mongolia
Authors: Wang Yu Ting , Wang Ding , Wang Xue Ya
Published: August 2007

The authors investigated the relationship between the incidence of suicide and meteorological factors in Huhhot, Inner Mongolia, for the period 1986-1991. Suicide rates were higher during the days of each month with extreme temperature and atmospheric pressure.
Review of Suicide Studies in Turkey
Authors: Sayil Isik
Published: August 2007

Official statistics in Turkey show that 3.33 per 100,000 population aged 15 years or over commit suicide every year. Suicides are more frequent in the cities and in the western part of the country. Although suicide rates are much lower than in Western Europe, suicide attempt rates reached comparable levels, around 145 per 100,000, in Ankara in 1995. Studies on the attitudes among the public and among psychiatrists reveal reluctance to face this growing problem.
Inmate Suicides in the Correctional Service of Canada
Authors: Laishes Jane
Published: August 2007

This article presents descriptive statistics on the 66 suicides occurring in federal institutions in Canada over a 4-year period. Criminological and institutional factors of those who committed suicide included lengthy involvement in the criminal justice system, a greater likelihood of being incarcerated for robbery or murder, and involvement in institutional incidents of a serious nature. In addition, 62% of the inmates who committed suicide had been transferred from other institutions within 6 months prior to suicide, though 59% evidenced no indicators of suicidal intent and 44% were not considered to be depressed at the time of suicide. Family problems (29%) were the most commonly hypothesized motivating factor in the suicides, followed by denial of a request for appeal, parole, or transfer (26%), fear of other inmates (24%), and substance abuse problems (21%). Current and planned suicide prevention and intervention strategies of the Correctional Service of Canada are discussed in the context of these findings.
Structural and isotopic constraints on fluid flow regimes and fluid pathways during upper crustal deformation: An example from the Taemas area of the Lachlan Orogen, SE Australia
Authors: Cox Stephen F.
Published: August 2007

Structural and stable isotope studies of calcite veins and host rocks in a 1000 m thick, Devonian limestone sequence in the Taemas area of the Lachlan Orogen in SE Australia indicate that externally derived fluids migrated through the sequence over a protracted interval during folding and associated reverse faulting at temperatures of ∼200°C. The evolution of fluid pathways was governed by growth of fold‐related and fault‐related fracture networks at transiently supralithostatic fluid pressures. The internal structures of veins indicate growth during repeated cycles of permeability enhancement and sealing. Systematic increase inδ18O of vein calcite upward through the limestone sequence, and the presence of an O isotope alteration front in the vein system, is related to buffering of fluid compositions by fluid‐rock reaction during upward migration of overpressured, lowδ18O fluids. Repeated switching of fractures between high‐permeability and low‐permeability states promoted episodic flow and changes in flow paths during progressive deformation. A lack of significant migration of the isotopic front during the flow history is consistent with fluid‐rock interaction being associated with numerous, separate pulses of fluid ascending through the percolation network. Irregular variations in fluidδ18O with time during vein growth are interpreted to be driven by repeated changes in reactive path lengths, reaction rates, and flow rates in a discontinuous flow regime. Systematic upward changes in veinδ18O over an area of 20 km2requires that on a time‐averaged basis, most of the vein system was hydraulically well connected to the external fluid reservoir and that growth of the fracture network occurred by fluid‐driven, invasion percolation processes. Repeated failure and sealing events in the fracture system are interpreted to have been driven by episodic migration of fluid pressure waves up through the fracture network, possibly in response to deeper level fault rupture events repeatedly breaching an overpressured fluid reservoir.
Transport above the Asian summer monsoon anticyclone inferred from Aura Microwave Limb Sounder tracers
Authors: Park Mijeong , Randel William J. , Gettelman Andrew , Massie Steven T. , Jiang Jonathan H.
Published: August 2007

Tracer variability above the Asian summer monsoon anticyclone is investigated using Aura Microwave Limb Sounder (MLS) measurements of carbon monoxide, ozone, water vapor, and temperature during Northern Hemisphere summer (June to August) of 2005. Observations show persistent maxima in carbon monoxide and minima in ozone within the anticyclone in the upper troposphere–lower stratosphere (UTLS) throughout summer, and variations in these tracers are closely related to the intensity of underlying deep convection. Temperatures in the UTLS are also closely coupled to deep convection (cold anomalies are linked with enhanced convection), and the three‐dimensional temperature patterns are consistent with a dynamical response to near‐ equatorial convection. Upper tropospheric water vapor in the monsoon region is strongly coherent with deep convection, both spatially and temporally. However, at the altitude of the tropopause, maximum water vapor is centered within the anticyclone, distant from the deepest convection, and is also less temporally correlated with convective intensity. Because the main outflow of deep convection occurs near ∼12 km, well below the tropopause level (∼16 km), we investigate the large‐scale vertical transport within the anticyclone. The mean vertical circulation obtained from the ERA40 reanalysis data set and a free‐running general circulation model is upward across the tropopause on the eastern end of the anticyclone, as part of the balanced three‐dimensional monsoon circulation. In addition to deep transport from the most intense convection, this large‐scale circulation may help explain the transport of constituents to tropopause level.
Morphology and mechanics of submarine spreading: A case study from the Storegga Slide
Authors: Micallef Aaron , Masson Douglas G. , Berndt Christian , Stow Dorrik A. V.
Published: August 2007

Spreading is a common type of ground failure in subaerial environments. However, this type of mass movement has hardly been documented in submarine settings. In this paper we show that spreading covers at least 25% of the Storegga Slide scar area, a giant submarine slide located offshore mid‐Norway. The morphological signature of spreading is a repetitive pattern of ridges and troughs oriented perpendicular to the direction of movement. Two modes of failure can be identified: retrogressive failure of the headwall and slab failure and extension, both involving the breakup of a sediment unit into coherent blocks. These blocks are displaced downslope along planar slip surfaces. Limit equilibrium modeling indicates that loss of support and seismic loading are the main potential triggering mechanisms. The extent of displacement of the spreading sediment is controlled by gravitationally induced stress, angle of internal friction of the sediment, pore pressure escape, and friction. The resulting block movement pattern entails an exponential increase of displacement and thinning of the failing sediment with distance downslope. Sediment properties explain the remaining spatial variation of ridge and trough morphologies associated with spreading.
Little River Experimental Watershed, Tifton, Georgia, United States: A geographic database
Authors: Sullivan D. G. , Batten H. L. , Bosch D. , Sheridan J. , Strickland T.
Published: August 2007

The Little River Experimental Watershed is located in the headwaters of the Upper Suwannee River basin and is one of twelve national benchmark watersheds participating in the U.S. Department of Agriculture Conservation Effects Assessment Project–Watershed Assessment Studies. A geographic database has been established to include topography, land use, hydrology, soil distribution, watershed boundaries, and site locations for all weirs, rain gauges, soil moisture sites, and climate stations. These data provide the foundation for integrating point‐based measurements with landscape attributes. Each spatial layer can be accessed individually for use within a geographic information system. The watershed boundary layer will serve as the base map, projected into universal transverse Mercator coordinates (zone 17), using NAD83 as the datum and GRS80 as the ellipsoid. Data may be accessed via ftp://www.tiftonars.org/.
Meteorological bias in satellite estimates of aerosol‐cloud relationships
Authors: Mauger Guillaume S. , Norris Joel R.
Published: August 2007

Several recent studies have reported a substantial correlation between satellite retrievals of aerosol optical depth (AOD) and cloud fraction, which is ascribed to an aerosol microphysical mechanism. Another possible explanation, however, is that the history of meteorological forcing controls both AOD and cloud fraction. The present study examines the latter hypothesis by comparing meteorological conditions along parcel back‐trajectories for cases of large and small AOD and cloud fraction. Cloud and aerosol observations are obtained from the MODIS instrument aboard Terra, and meteorological information is obtained from ECMWF analyses. For continuity with previous investigations, the analysis focuses on the stratocumulus cloud region of the Northeast Atlantic during June through August 2002, the season of maximum cloud cover. Results show that scenes with large AOD and large cloud fraction had origins closer to Europe and experienced greater lower tropospheric static stability (LTS) during the past 2–3 days than did scenes with small AOD and small cloud fraction. Controlling for variations in LTS reduces the dependence of cloud fraction on AOD by at least 54%. We conclude that meteorological forcing must be accounted for in assessing aerosol impacts on cloud forcing, and that doing so requires a Lagrangian analysis of parcel histories.
Variations in the low‐ and middle‐latitude topside ion concentration observed by DMSP during superstorm events
Authors: Heelis R. A. , Coley W. R.
Published: August 2007

Observations of the topside ion number density by the DMSP satellites on the dayside near 0930 LT and near dusk describe a characteristic evolution during the course of three superstorm events in November 2001, November 2003, and November 2004. Density enhancements at middle latitudes and at the equator may be identified as separate features that may appear together but can evolve independently. These characteristics are consistent with the action of both upward (outward) E × B drifts and equatorward neutral winds and it is suggested that both F region drivers are required to reproduce the observed behavior on these occasions. Upward excursions of the E × B drift at the equator may be short‐lived compared to the satellite orbit period of about 100 min but may also exist for longer periods under the influence of penetration fields and modified dynamo fields. Upward drifts at middle latitudes may be induced by meridional winds and by the high‐latitude convection pattern as it expands to latitudes as low as 40 degrees magnetic.
Cluster observations in the inner magnetosphere during the 18 April 2002 sawtooth event: Dipolarization and injection at r = 4.6 RE
Authors: Ohtani S. , Korth H. , Brandt P. C. , Blomberg L. G. , Singer H. J. , Henderson M. G. , Lucek E. A. , Frey H. U. , Zong Q. , Weygand J. M. , Zheng Y. , Lui A. T. Y.
Published: August 2007

The present study examines a sawtooth injection event that took place around 0800 UT on 18 April 2002 when the Cluster spacecraft were located in the inner magnetosphere in the premidnight sector. In association with this injection, Cluster, at a radial distance of 4.6 RE, observed that the local magnetic field became more dipolar and that both ion and electron fluxes increased without notable energy dispersion. These features were accompanied by intensifications of the equatorward component of a double‐oval structure and also by an enhancement of the ring‐current oxygen ENA flux. The event was also accompanied by large magnetic field (a few tens of nT) and electric field (a few tens of mV/m) fluctuations with characteristic timescales of a few tens of seconds. These observations strongly suggest that this sawtooth injection extended not only widely in local time but also deeply into the inner magnetosphere. Interestingly, Cluster repeatedly observed dipolarization‐like signatures afterward, which, however, were not associated with enhancements of local energetic ion flux or with geosynchronous dipolarization or injection signatures. Instead, these magnetic signatures were accompanied by oscillatory plasma motion in the radial direction with a characteristic timescale of about 10 min, which appears to be related to the westward propagation of a spatially periodic auroral structure. The associated azimuthal electric field component was well correlated with the time derivative of the north‐south magnetic field component, suggesting that the observed electric field is inductive. These findings suggest that electromagnetic processes far inside geosynchronous orbit play an important role in energization of energetic ions and auroral dynamics during magnetospheric storms.
Ozone differences between near‐coastal and offshore sites in New England: Role of meteorology
Authors: Darby Lisa S. , McKeen Stuart A. , Senff Christoph J. , White Allen B. , Banta Robert M. , Post Madison J. , Brewer W. Alan , Marchbanks Richard , Alvarez Raul J. , Peckham Steven E. , Mao Huiting , Talbot Robert
Published: August 2007

Time series from two ozone monitoring stations are evaluated, one on an island several km off the New England coast, the other several km inland in New Hampshire. In the summer of 2002, during the New England Air Quality Study 2002 (NEAQS‐2002), ozone measurements at the island station, Appledore Island (ADI), were consistently higher than at the inland station, Thompson Farm (TF). We hypothesized that the differences in ozone concentrations were due to transport differences driven by mesoscale meteorology, since neither site was in a source region. We found that the Appalachian Trough, coastal cold fronts and coastal stationary fronts at times caused TF to have westerly component flow while ADI had southerly component flow. In these situations, the southwesterly flow along the New England coast brought ozone and precursors to ADI from metropolitan areas to the southwest (e.g., Boston). Conversely, the air transported to TF from the west was contaminated by fewer upstream sources, and therefore the ozone was lower at TF. The sea breeze was also a factor, which tended to have the contrasting effect of nearly equalizing the ozone concentrations at the two sites by transporting ozone‐rich air already impacting ADI inland to TF. Enhanced measurements from the NEAQS‐2002 study were used in the analysis, including radar wind profilers, Doppler and ozone profiling lidars, and radiosondes launched from a ship. We also assessed model performance for two models, WRF/Chem and MM5/Chem, for four key days.
Global synchronization in lattices of coupled chaotic systems
Authors: Juang Jonq , Li Chin-Lung , Liang Yu-Hao
Published: August 2007

Based on the concept of matrix measures, we study global stability of synchronization in networks. Our results apply to quite general connectivity topology. In addition, a rigorous lower bound on the coupling strength for global synchronization of all oscillators is also obtained. Moreover, by merely checking the structure of the vector field of the single oscillator, we shall be able to determine if the system is globally synchronized.
Optical characterization of Nd3+- and Er3+-doped lead-indium-phosphate glasses
Authors: Brito Taísa B. , Vermelho M. V. D. , Gouveia E. A. , de Araujo M. T. , Guedes I. , Loong C.-K. , Boatner L. A.
Published: August 2007

In this work, Judd–Ofelt analysis is applied to rare-earth-doped lead-indium-phosphate glasses (RE-PbInPO4, where RE=Er3+ and Nd3+) in order to evaluate their potential as both glass laser systems and amplifier materials. The phenomenological Judd–Ofelt parameters Ω(2), Ω(4), and Ω(6) are determined for both rare-earth ions together with their quality factors and compared with the equivalent parameters for several other host glasses. The spontaneous emission probabilities and the lifetimes of the Nd3+ F43/2 laser transitions are determined and analyzed as a function of the optical quality factor. For Nd3+-PbInPO4, glass fluorescence emission (890, 1058, and 1330 nm) lines are observed. Highly efficient infrared-to-visible frequency up-conversion at 530, 550, and 670 nm as well as an intense infrared fluorescence emission (∼1540 nm) is observed in Er3+-doped PbIn(PO4) glasses pumped using 800 nm radiation excitation.
Dynamics of interacting Brownian particles: A diagrammatic formulation
Authors: Szamel Grzegorz
Published: August 2007

We present a diagrammatic formulation of a theory for the time dependence of density fluctuations in equilibrium systems of interacting Brownian particles. To facilitate derivation of the diagrammatic expansion, we introduce a basis that consists of orthogonalized many-particle density fluctuations. We obtain an exact hierarchy of equations of motion for time-dependent correlations of orthogonalized density fluctuations. To simplify this hierarchy we neglect contributions to the vertices from higher-order cluster expansion terms. An iterative solution of the resulting equations can be represented by diagrams with three- and four-leg vertices. We analyze the structure of the diagrammatic series for the time-dependent density correlation function and obtain a diagrammatic interpretation of reducible and irreducible memory functions. The one-loop self-consistent approximation for the latter function coincides with mode-coupling approximation for Brownian systems that was derived previously using a projection operator approach.
Molecular simulation studies of nanoscale friction between phosphorylcholine self-assembled monolayer surfaces: Correlation between surface hydration and friction
Authors: He Yi , Chen Shengfu , Hower Jason C. , Bernards Matthew T. , Jiang Shaoyi
Published: August 2007

We performed all-atom molecular dynamics simulations to study the friction between surfaces covered with two phosphorylcholine self-assembled monolayers (PC-SAM) under shear. PC-SAM surfaces with a √7×√7R19° lattice structure and a parallel arrangement of the head groups were used as model zwitterionic surfaces. They provide a full representation of the zwitterionic nature of phospholipid surfaces, which are believed to play an important role in the lubrication of biological joints such as knees and hips. The surfaces were immersed in aqueous solutions and kept in contact with two regions of bulk water. Sodium chloride and potassium chloride solutions at various concentrations were employed to study the effects of the presence of ions on friction. The results show a strong relationship between surface hydration and friction. Higher ionic concentrations or ions with shorter Debye lengths cause a larger disruption to the hydration around the zwitterionic surfaces, leading to larger friction forces. In addition, the results show that under nanoscale confinement, the friction coefficients of PC-SAM surfaces in pure water are directly proportional to both shear velocity and surface separation distance. These results are comparable to previously published experimental studies.
Structural and optical properties of cubic-InN quantum dots prepared by ion implantation in Si (100) substrate
Authors: Huang Yi-Kai , Liu Chuan-Pu , Lai Yen-Lin , Wang Cheng-Yu , Lai Yi-Feng , Chung Hung-Chin
Published: August 2007

The authors have synthesized InN quantum dots by ion implantation into a Si (100) substrate followed by a postannealing process. X-ray photoemission spectroscopy data verified the formation of In–N bonding in both as-implanted and postannealed samples. Diffraction patterns from transmission electron microscopy (TEM) confirm that the dots are of cubic crystal (zinc-blende phase) with no presence of wurtzite InN. The silicon matrix provides a constraint for the formation of the InN cubic metastable phase. However, dislocations were revealed by high resolution TEM at the interfaces between the dots and the silicon. In addition, the authors found that as the annealing temperature or time increases, dot size increases and dot density decreases. Furthermore, they demonstrate that the main emission energy of zinc-blende InN dots is about 0.736eV.
Molecular simulations of Hugoniots of detonation product mixtures at chemical equilibrium: Microscopic calculation of the Chapman-Jouguet state
Authors: Bourasseau Emeric , Dubois Vincent , Desbiens Nicolas , Maillet Jean-Bernard
Published: August 2007

In this work, we used simultaneously the reaction ensemble Monte Carlo (ReMC) method and the adaptive Erpenbeck equation of state (AE-EOS) method to directly calculate the thermodynamic and chemical equilibria of mixtures of detonation products on the Hugoniot curve. The ReMC method [W. R. Smith and B. Triska, J. Chem. Phys. 100, 3019 (1994)] allows us to reach the chemical equilibrium of a reacting mixture, and the AE-EOS method [J. J. Erpenbeck, Phys. Rev. A 46, 6406 (1992)] constrains the system to satisfy the Hugoniot relation. Once the Hugoniot curve of the detonation product mixture is established, the Chapman-Jouguet (CJ) state of the explosive can be determined. A NPT simulation at PCJ and TCJ is then performed in order to calculate direct thermodynamic properties and the following derivative properties of the system using a fluctuation method: calorific capacities, sound velocity, and Grüneisen coefficient. As the chemical composition fluctuates, and the number of particles is not necessarily constant in this ensemble, a fluctuation formula has been developed to take into account the fluctuations of mole number and composition. This type of calculation has been applied to several usual energetic materials: nitromethane, tetranitromethane, hexanitroethane, PETN, and RDX.
Experimental determination of the ionization potentials of the first five members of the nanodiamond series
Authors: Lenzke K. , Landt L. , Hoener M. , Thomas H. , Dahl J. E. , Liu S. G. , Carlson R. M. K. , Möller T. , Bostedt C.
Published: August 2007

The ionization potentials of size- and isomer-selected diamondoids (nanodiamond containing one to five crystal cages) have been measured by means of total-ion-yield spectroscopy. We find a monotonic decrease of the ionization potential with increasing diamondoid size. This experimental result is compared to recent theoretical predictions and comparable investigations on related carbon clusters, the fullerenes, which show isomer effects to be stronger than size dependence.
A laser probe measurement of cavitation bubble dynamics improved by shock wave detection and compared to shadow photography
Authors: Petkovšek Rok , Gregorčič Peter
Published: August 2007

High-intensity light from a laser pulse can produce optical breakdown in a liquid, followed by a shock wave and the growth of a cavitation bubble. When the bubble reaches its maximum radius the liquid pressure causes it to collapse, which in turn initiates the growth of another bubble. The oscillations can repeat themselves several times, and a shock wave is emitted after every collapse. In our study the breakdown was induced in distilled water by a Nd:YAG pulsed laser, which was designed for ocular photodisruption. The main focus of our experiments was measurement of the cavitation bubble and the shock waves using an optical probe based on deflections of a laser beam. The applied experimental setup made it possible to carry out one- or two-dimensional scanning of the cavitation bubble based on automatic control of the experiment. Since the beam-deflection probe (BDP) allowed simultaneous measurements of the cavitation bubble and the shock waves, we developed a method for reducing the measurement noise of the BDP scanning. This improvement includes an analysis of the secondary shock waves and leads to a significant reduction in the noise of the measurement. Simultaneous measurements based on shadow photography were used as a comparative method during the experiment.
Effects of an underlayer on the sensitivity of top spin valves
Authors: Tang Xiao-Li , Zhang Huai-Wu , Su Hua , Zhong Zhi-Yong , Jing Yu-Lan
Published: August 2007

Top spin valves of NiFe/Cu/NiFe/FeMn/Ta with a Ta or Cu underlayer were investigated. Measurements showed a substantial magnetoresistance ratio for samples with either type of underlayer. The sensitivity of spin valves, defined as the slope of the magnetoresistance curve between 10% and 90% of the giant magnetoresistance ratio, was much greater for the Ta than for the Cu underlayer. This difference in sensitivity is attributed to magnetization reversal of the free layer (NiFe) directly deposited on the underlayer. Investigation of the surface microstructure and composition of Ta and Cu/NiFe bilayers indicated that Cu atoms, which possess lower surface free energy than the other elements in the bilayers, float out to the surface of NiFe free layer and are responsible for the lower sensitivity of the spin valve. Therefore, by choosing underlayer material with suitable surface free energy, top spin valves with high sensitivity can be realized.
Intrinsic electrophilic properties of nucleosides: Photoelectron spectroscopy of their parent anions
Authors: Stokes Sarah T. , Li Xiang , Grubisic Andrej , Ko Yeon Jae , Bowen Kit H.
Published: August 2007

The nucleoside parent anions 2′-deoxythymidine−, 2′-deoxycytidine−, 2′-deoxyadenosine−, uridine−, cytidine−, adenosine−, and guanosine− were generated in a novel source, employing a combination of infrared desorption, electron photoemission, and a gas jet expansion. Once mass selected, the anion photoelectron spectrum of each of these was recorded. In the three cases in which comparisons were possible, the vertical detachment energies and likely adiabatic electron affinities extracted from these spectra agreed well with the values calculated both by Richardson et al. [J. Am. Chem. Soc. 126, 4404 (2004)] and by Li et al. [Radiat. Res. 165, 721 (2006)]. Through the combination of our experimental results and their theoretical calculations, several implications emerge. (1) With the possible exception of dG−, the parent anions of nucleosides exist, and they are stable. (2) These nucleoside anions are valence anions, and in most cases the negative charge is closely associated with the nucleobase moiety. (3) The nucleoside parent anions we have generated and studied are the negative ions of canonical, neutral nucleosides, similar to those found in DNA.
Study of magnetic properties and relaxation in amorphous Fe73.9Nb3.1Cu0.9Si13.2B8.9 thin films produced by ion beam sputtering
Authors: Celegato F. , Coïsson M. , Magni A. , Tiberto P. , Vinai F. , Kane S. N. , Modak S. S. , Gupta A. , Sharma P.
Published: August 2007

Amorphous Fe73.9Nb3.1Cu0.9Si13.2B8.9 thin films have been produced by ion beam sputtering with two different beam energies (500 and 1000eV). Magnetic measurements indicate that the samples display a uniaxial magnetic anisotropy, especially for samples prepared with the lower beam energy. Magnetization relaxation has been measured on both films with an alternating gradient force magnetometer and magneto-optical Kerr effect. Magnetization relaxation occurs on time scales of tens of seconds and can be described with a single stretched exponential function. Relaxation intensity turns out to be higher when measured along the easy magnetization axis.
Two laterally arranged quantum dot systems with strong capacitive interdot coupling
Authors: Hübel A. , Weis J. , Dietsche W. , Klitzing K. v.
Published: August 2007

A method has been developed to form two quantum dot systems in lateral arrangement in a two-dimensional electron system of a GaAs–AlGaAs heterostructure with strong capacitive interdot coupling. In the authors’ design, the interdot capacitance can reach more than one-third of the single-dot capacitance while tunneling between the dots is excluded. This has been achieved by a floating metallic electrode covering both quantum dots, a method already used in split-gate designs before. Here, however, they have reduced the capacitive coupling of this floating gate to other electrodes in the surroundings by an etching technique to obtain a large interdot coupling.
Local buckling of carbon nanotubes under bending
Authors: Wang Q. , Liew K. M. , He X. Q. , Xiang Y.
Published: August 2007

The discovery of a local buckling instability of a single-walled carbon nanotube (CNT) that is subjected to point loading in its flexural direction through molecular mechanics simulations via the MATERIALS STUDIO software package is reported in the letter. The sudden decrease of the stiffness of the CNT at the onset of the local instability is found from reliable observations of the second derivation of the strain energy of the CNT under bending. A mechanics model is developed to predict the onset of the local instability, and the effectiveness of the model is verified by molecular mechanics simulations.