bluuebunny/crossref_metadata_2025 huggingface dataset:
New amphoteric surfactant containing a 2‐hydroxyalkyl group: III. Performance of binary systems of amphoteric/anionic surfactants
Authors: Takai M. , Hidaka H. , Ishikawa S. , Takada M. , Moriya M.
Published: August 2007

The performance of new amphoteric surfactants, N‐(2‐hydroxyethyl)‐N‐(2‐hydroxyalkyl)‐β‐alanines (HAA), and their oxyethylated derivatives (HAA‐nEO) was studied in blends with conventional anionic surfactants. Viscosity, ultraviolet (UV) spectroscopy, surface tension, foaming power, dye solubilization and detergency were measured for the blends of various compositions. The interaction between HAA and sodium linear alkylbenzene sulfonate (LAS) was discussed with respect to the deviation of molar extinction coefficient in the UV spectra. A complex formation was assumed. A notable change in viscosity of 1.0% aqueous solutions was observed at pH 8.0 for the compositions of HAA/LAS (3:1) and HAA/sodium lauryl sulfate (4:1). The binary systems exhibited excellent detergency and other surface active properties, and indicated synergistic effects at a certain weight ratio. Human and rabbit skin irritation also was evaluated.
Trends in Neonatal Intestinal Obstruction in a Developing Country, 1996–2005
Authors: Ekenze S. O. , Ibeziako S. N. , Ezomike U. O.
Published: August 2007

Background

Despite the advances in neonatal surgery, the outcome of neonatal intestinal obstruction (NIO) in many developing countries has been reported to be poor. This study describes the trends in NIO, including the contributory factors in southeast Nigeria.

Methods

We performed a comparative analysis of 128 consecutive NIO managed from January 1996 to December 2005 at the University of Nigeria Teaching Hospital, Enugu, in southeast Nigeria.

Results

Fifty‐five (43.0%) neonates were managed in the first 5 years (group A) and 73 (57.0%) in the last 5 years (group B). Etiology of obstruction did not vary significantly in the two groups. Average duration of symptoms before presentation fell from 5.9 days (group A) to 4.7 days (group B). With exception of Hirschsprung’s disease (HD), all other cases required operative treatment. In HD, colostomy rate declined from 44.4% (group A) to 26.7% (group B). More neonates in group B were managed with general anesthesia and perioperative third‐generation cephalosporin antibiotics (p < 0.01). While complication rate did not vary significantly in the two groups (group A, 42%; group B, 40.3%), survival improved (group A, 61.8%; group B, 72.6%). Earlier presentation, improved manpower, and use of potent antibiotics may have contributed to the improved outcome. Challenges in the form of lack of neonatal intensive care facilities and dearth of qualified personnel persist.

Conclusion

There is a trend toward earlier presentation and increased survival of babies with NIO in our setting. Improving the existing facilities and trained manpower, and establishing collaboration with centers that have excellent results may further encourage the trend.
Oxidation of Sodium Dodecylbenzenesulfonate with Chrysotile: On‐line Monitoring by Membrane Introduction Mass Spectrometry
Authors: Fachini Adriano , Mendes Maria A. , Joekes Inés , Eberlin Marcos N.
Published: August 2007

Chrysotile was tested for anionic surfactant (SDBS) removal from aqueous solutions. Results showed that the reduction was due to a catalytic process onto the chrysotile surface, which is formed of hydroxyl groups. Trap and release membrane introduction mass spectrometry using a modified direct insertion membrane probe (DIMP‐T&R‐MIMS) was used to monitor on‐line SDBS oxidation by air in an aqueous alkaline media containing chrysotile. It was possible to estimate the amount of CO2 formed in SDBS catalyzed reaction through quantification of CO2 formed by the hydrolysis of MgCO3. A mass balance for the SDBS reaction is proposed. DIMP‐T&R‐MIMS monitoring identified no VOCs or SVOCs as degradation intermediates, but CO2 was detected to account for SDBS degradation. Hence, simple chrysotile adsorption is excluded as a main process of SDBS consumption, and a “SDBS in‐CO2 out” mechanism on the chrysotile surface accounts for the experimental observations.
Post‐translational modification of barley LTP1b: The lipid adduct lies in the hydrophobic cavity and alters the protein dynamics
Authors: Wijesinha-Bettoni Ramani , Gao Chunli , Jenkins John A. , Mackie Alan R. , Wilde Peter J. , Mills E.N. Clare , Smith Lorna J.
Published: August 2007

NMR techniques have been used to characterise the effects of a lipid‐like post‐translational modification on barley lipid transfer protein (LTP1b). NMR chemical shift data indicate that the lipid‐like molecule lies in the hydrophobic cavity of LTP1b, with Tyr 79 being displaced to accommodate the ligand in the cavity. The modified protein has a reduced level of backbone amide hydrogen exchange protection, presumably reflecting increased dynamics in the protein. This may result from a loosening of the protein structure and may explain the enhanced surface properties observed for LTP1b.
One‐stage repair for combined fistulas: Myth or reality?
Authors: Ojengbede O.A. , Morhason‐Bello I.O. , Shittu O.
Published: August 2007

Objective

The repair of combined vesico‐vaginal fistulas (VVFs) and recto‐vaginal fistulas (RVFs) is challenging to both surgeon and patient. The multistage approach involves at least 3 surgical sessions, all associated with morbidity and sometimes with a colostomy procedure as well. The outcomes of the 1‐stage approach were examined.

Methods

Twenty patients aged between 16 and 38 years were recruited for a multicenter study conducted from March 2005 to August 2006. Prolonged obstructed labor was the cause of all fistulas. The VVFs were mainly midvaginal (60%), juxtaurethral (25%), and juxtacervical (15%). The RVFs measured between 1 and 3 cm, they were low in 70% of cases, and 1 was associated with fourth‐degree perineal tear. Bowel preparation was performed in all patients prior to surgery. No patient underwent temporary colostomy.

Results

Both VVFs and VVFs were successfully closed in all patients, as evidenced by the continence dye test.

Conclusion

The combined repair relieves economic constraints and emotional challenges, and it accelerates restoration to health and social reintegration for women affected with both VVFs and RVFs.
Building Up Modernity?: The Changing Spatial Representations of State Power in a Chinese Socialist “Model Community”
Authors: HO WING CHUNG
Published: August 2007

This essay looked into how a group of residents in a Chinese community negotiated with the ideological tropes inscribed in the spatial, which aimed to build up state–people trust on the future course of national development. Under investigation was a slum-turned-socialist-model community called “Cucumber Lane” in two historical junctures in which its spatial settings were radically reorganized. It was argued that the two spatial reorganizations exemplified two major state-led projects of modernity, each of which entailed a specific representation of space that ideologically adumbrated a specific course of national development. It was found that while the residents welcomed the project of modernity launched in the 1960s with enthusiasm, they received the other in the 1990s largely with apathy, and even with mistrust and disbelief.
Effect on Richtmyer-Meshkov instability of deviation from sinusoidality of the corrugated interface between two fluids
Authors: Gupta M.R. , Roy S. , Sarkar S. , Khan M. , Pant H.C. , Srivastava M.K.
Published: August 2007

The effect of arbitrary shapes of the two fluid interface on Richtmyer-Meshkov (RM) instability is investigated. It is seen that deviation from sinusoidality in the geometrical shapes has interesting influence on the overall growth rate. In the linear theoretic domain the RM instability may be actually reduced for suitable geometrical shape of the interface. The figures given demonstrate this aspect. This result is important in designing ICF target and also gives an idea to tailor laser pulse for optimum stability of RM modes.
Stabilization and equilibrium control of a new pneumatic cart-seesaw system
Authors: Lin J. , Zhan J. H. , Chang Julian
Published: August 2007

This investigation describes the mechanical configuration and control environment for a novel cart-seesaw system. This mechanism is called a super articulated mechanical system (SAMS). The system comprises a cart that slides on the pneumatic rodless cylinder. The rodless cylinder is double-acting with the carrier bracket, on which a cart is a pinion mechanism for the tracks. The cart-seesaw system brings the cart from any initial position to a desired position on the seesaw by applying an appropriate force to the cart and thus adjusting the angle of the seesaw. The position of a cart denotes the first degree of freedom, which is activated by a pneumatic proportional valve, and the angle of the seesaw indicates the second degree of freedom that is not actuated. Consequently, the proposed new pneumatic cart-seesaw system is straightforward to construct and direct to operate in different scenarios of performance. A state feedback controller is applied for stabilization of the equilibrium point of the system. Moreover, this study adds a supervisory controller that takes control action in extreme situations. Test results reveal excellent properties in control performance. The proposed product can be extensively applied in SAMS and pneumatic control for robotics control laboratory.
Human Rights Violations before International Tribunals: Reflections onResponsibility of International Organizations
Authors: ACQUAVIVA GUIDO
Published: August 2007

The UN Security Council, as ‘parent body’ of the two ad hoc Tribunals, never introduced explicit rules on how to compensate accused persons for violations of their rights imputable to the Tribunals' organs. Notwithstanding the absence of such rules, a series of decisions by ICTYand ICTR chambers show the willingness of these institutions to address such violations when they occur. In doing so, the Tribunals appear to have followed some of the same principles on responsibility of international organizations as are being elaborated by the International Law Commission (ILC). By analysing these parallel processes, the author suggests that the elaboration of rules by the ad hoc Tribunals in the field of human rights violations and the codification by the ILC of rules on international responsibility, although distinct in aim and scope, might mutually benefit each other andshed some light on the difficulties of applying such principles in practice.
Democratic Governance and Post-conflict Reconstruction
Authors: COGEN MARC , DE BRABANDERE ERIC
Published: August 2007

The concept of democracy has long fuelled controversy among international legal scholars, especially concerning its definition. This article is an attempt to single out three constitutive elements of democracy that have been subject to extensive scrutiny in the practice of electoral assistance and the more comprehensive peace-building and state-building missions that the UN has taken up or supported since the end of the twentieth century: freeand fair elections, freedom of association – with emphasis on the freedom to establish political parties – and freedom of expression. In doing so, this paper examines the role and the importance of each of these three constitutive elements in the practice pertaining to post-conflict reconstruction of Kosovo, East Timor, Afghanistan, and Iraq.
Communitarianism and Suicide Prevention: Proposals for the Year 2000
Authors: Lester David
Published: August 2007

A review of anthropological, sociological, and psychological theories of suicidal behavior indicates that a disruption in social relationships and a breakdown in community networks increase the risk of suicide. Current suicide prevention tactics fail to address these problems, and suggestions are made for tactics that would focus on the underlying causes of suicide, tactics consistent with a communitarian philosophy and tactics that could guide us into the 21st century.
Suicide in Greek Prisons: 1977 to 1996
Authors: Spinellis Calliope D , Themeli Olga
Published: August 2007

Data obtained from the records of the Greek Ministry of Justice revealed that there were 457 deaths in the Greek prison system (which includes prisons, mental hospitals and other general hospitals) over the past 20 years. Of these deaths, 93 were recorded as suicides — an average of 4.65 suicides per year or 112 per 100,000 inmates classified as convicted, on remand or hospitalized. The suicide rates fluctuated widely, from a low rate of 32.3 in 1982 to the incredibly high rate of 390.8 in 1979 (11 total suicides, 10 of which occurred in prison hospitals). The present study, the first of its kind in Greece, was based solely on unpublished prison data, which revealed defects in recording (e. g., 11% of the deaths recorded by the correctional administration remained without specification of cause in the years 1977 through 1996; social and penal demographic data of the inmates who committed suicide were kept unsystematically; detailed information on the circumstances of suicide was not always available, etc.). Despite a noticeable decrease in the suicide rate in the years 1995 and 1996, the limited data suggest that the suicide rate in the Greek prison system has basically remained stable over the past 20 years.
Prevention of Suicides in Penal Institutions in The Netherlands
Authors: Blaauw Eric , Carrière Raphaela M. , Schilder Frans , van de Lande Stef
Published: August 2007

As in other countries, suicides are a matter of great concern in The Netherlands. This article addresses suicide-prevention measures in prisons in The Netherlands. It focuses primarily on screening, monitoring, incapacitation, psychological support, and transferal to specialized institutions. In addition, it asks which practices are common, which can be improved, and the limitations of certain strategies. Relatively speaking, The Netherlands does not appear to be doing too badly in terms of preventive measures, although there is room for improvement.
A Solution to the Problem of Jail Suicide
Authors: Cox Judith F , Morschauser Pamela C
Published: August 2007

Suicide in local jail facilities can be reduced through interagency cooperation and the implementation of core services. In 1985, the State of New York implemented a comprehensive suicide prevention program within its upstate local jail facilities. The program utilized key coordination strategies and risk-management service components. It addressed not only the immediate needs of inmates with high-risk profiles, but also focused on the impact of the stressful jail experience on this already vulnerable population. Despite a nearly 100% increase in the jail population, there has been more than a 150% decrease in jail suicides since program implementation.
Evolution of freshwater plumes and salinity fronts in the northern Bay of Bengal
Authors: Wu Lingjuan , Wang Fan , Yuan Dongliang , Cui Maochang
Published: August 2007

The evolution of freshwater plumes and the associated salinity fronts in the northern Bay of Bengal (henceforth the bay) is studied using rotated empirical orthogonal function (REOF) analysis and extended associate pattern analysis (EAPA). The results show that sea surface salinity distribution is featured by eastern‐bay and western‐bay plumes in the northern bay during different seasons. The western‐bay plume begins in early July, peaks in late August, and then turns into a bay‐shaped plume with the two plumes in either side of the bay, which peaks in late October. The southward extension of the western‐bay plume can be explained by the southwestward geostrophic flow associated with the cyclonic gyre in the northern bay, which counters the northeastward Ekman drift driven by wind stress. The offshore expansion of the western‐bay plume is induced by the offshore Ekman drift which also produces a salinity front near the east coast of India. The bay‐shaped plume appears when the cyclonic gyre shifts westward and a weak anticyclonic gyre occupies the northeastern bay. As the season advances, the western part of the bay‐shaped plume decays while the eastern part persists until the following June, which is believed to be associated with the anticyclonic gyre in the northern bay. The evolution of the plumes except the eastern part of the bay‐shaped plume in fall can be partly explained by the seasonal variation of mass transport associated with the Sverdrup balance. The fact that the western‐bay (eastern‐bay) plume appears when surface freshwater flux in the northeastern bay increases (decreases) dramatically suggests that the plumes are not produced directly by surface freshwater flux. River discharge seems to be the freshwater source for the plumes and has little to do with the evolution of the plumes.
Forcing a three‐dimensional, hydrostatic, primitive‐equation model for application in the surf zone: 1. Formulation
Authors: Newberger P. A. , Allen J. S.
Published: August 2007

An Eulerian analysis for wave forcing of three‐dimensional (3D) wave‐averaged mean circulation in the surf zone is presented. The objective is to develop a dynamically consistent formulation for applications in a 3D primitive equation model. The analysis is carried out for the case of shallow‐water linear waves interacting with wave‐averaged depth‐independent horizontal currents that vary on larger space scales and timescales. Variations in wave properties are governed by a wave action equation that includes wave‐current interactions and dissipation representative of wave breaking. Wave forcing of the mean currents consists of a surface stress and a body force. The surface stress is proportional to the wave energy dissipation. The body force includes one term that is related to gradients of part of the radiation stress tensor and a second term that is related to the vortex force and is proportional to a product of the mean wave momentum and the vertical component of the mean vorticity vector. In addition, there is a nonzero normal velocity at the mean surface that arises from the divergence of the mean Eulerian wave mass flux. This velocity results in an additional momentum flux forcing of the mean flow. Applications of this formulation to the DUCK94 field experiment are presented in part 2.
Forcing a three‐dimensional, hydrostatic, primitive‐equation model for application in the surf zone: 2. Application to DUCK94
Authors: Newberger P. A. , Allen J. S.
Published: August 2007

A three‐dimensional primitive‐equation model for application to the nearshore surf zone has been developed. This model, an extension of the Princeton Ocean Model (POM), predicts the wave‐averaged circulation forced by breaking waves. All of the features of the original POM are retained in the extended model so that applications can be made to regions where breaking waves, stratification, rotation, and wind stress make significant contributions to the flow behavior. In this study we examine the effects of breaking waves and wind stress. The nearshore POM circulation model is embedded within the NearCom community model and is coupled with a wave model. This combined modeling system is applied to the nearshore surf zone off Duck, North Carolina, during the DUCK94 field experiment of October 1994. Model results are compared to observations from this experiment, and the effects of parameter choices are examined. A process study examining the effects of tidal depth variation on depth‐dependent wave‐averaged currents is carried out. With identical offshore wave conditions and model parameters, the strength and spatial structure of the undertow and of the alongshore current vary systematically with water depth. Some three‐dimensional solutions show the development of shear instabilities of the alongshore current. Inclusion of wave‐current interactions makes an appreciable difference in the characteristics of the instability.
Space weather monitoring by GPS measurements on board CHAMP
Authors: Jakowski N. , Wilken V. , Mayer C.
Published: August 2007

The availability of L‐band radio signals permanently transmitted by satellites of the Global Positioning System (GPS) has opened a new dimension for ionosphere sounding. Whereas ground‐based GPS measurement techniques have been developed already over many years, the space‐based GPS measurements on board Low Earth Orbiting (LEO) satellites are rather new. GPS measurements onboard the German georesearch satellite CHAMP were used to monitor the ionosphere on global scale since April 2001. Addressed here are the capabilities of the ionospheric radio occultation (IRO) technique for routinely monitoring the global ionosphere with the purpose of deriving value‐added data products and studying ionospheric perturbations. Also discussed is the use of zenith viewing GPS navigation data for reconstructing the three‐dimensional electron density distribution of the topside ionosphere/plasmasphere in the vicinity of the CHAMP orbit plane. Whereas the ground‐based measurements show strong horizontal redistribution of plasma during ionospheric storms, the space‐borne measurements indicate a severe vertical redistribution of the ionospheric plasma during the selected events. In this paper we review the capabilities of the space‐based GPS measurements performed on board CHAMP and discuss ionospheric/plasmaspheric perturbation processes caused by the strong space weather event on 20 November 2003. Space‐based GPS measurements have a high potential for routinely monitoring the ionosphere/plasmasphere systems, thus effectively contributing to global space weather monitoring activities.
Modeling the effects of throughfall reduction on soil water content in a Brazilian Oxisol under a moist tropical forest
Authors: Belk Elizabeth L. , Markewitz Daniel , Rasmussen Todd C. , Carvalho Eduardo J. Maklouf , Nepstad Daniel C. , Davidson Eric A.
Published: August 2007

Access to water reserves in deep soil during drought periods determines whether or not the tropical moist forests of Amazonia will be buffered from the deleterious effects of water deficits. Changing climatic conditions are predicted to increase periods of drought in Amazonian forests and may lead to increased tree mortality, changes in forest composition, or greater susceptibility to fire. A throughfall reduction experiment has been established in the Tapajós National Forest of east‐central Amazonia (Brazil) to test the potential effects of severe water stress during prolonged droughts. Using time domain reflectometry observations of water contents from this experiment, we have developed a dynamic, one‐dimensional, vertical flow model to enhance our understanding of hydrologic processes within these tall‐stature forests on well‐drained, upland, deep Oxisols and to simulate changes in the distribution of soil water. Simulations using 960 days of data accurately captured mild soil water depletion near the surface after the first treatment year and decreasing soil moisture at depth during the second treatment year. The model is sensitive to the water retention and unsaturated flow equation parameters, specifically the van Genuchten parameters θs, θr, and n, but less sensitive to Ks and α. The low root‐mean‐square error between observed and predicted volumetric soil water content suggests that this vertical flow model captures the most important hydrologic processes in the upper landscape position of this study site. The model indicates that present rates of evapotranspiration within the exclusion plot have been sustained at the expense of soil water storage.
Infrasonic tremor in the diffraction zone
Authors: Fee David , Garcés Milton
Published: August 2007

Volcanic tremor signals recorded by an infrasound array ∼12.5 km from the active vent of Kīlauea Volcano show clear diurnal amplitude variations and originate from a well defined direction pointing to the active Pu`u `Ō`ō crater complex. Spectral amplitudes between 0.02–0.3 Hz, a proxy for wind speed, increase when the wind speeds increase during the daytime. Spectral amplitudes between 0.5–3 Hz, where infrasonic tremor is concentrated, increase when the wind speeds decrease at night. Power spectrum analysis shows that when ambient noise levels drop, infrasonic tremor amplitudes rise. Array processing confirms this relationship and reveals tremor detections and amplitudes decrease during the day. These changes in infrasonic tremor spectral amplitude and coherence are most likely due to diurnal variations in atmospheric boundary layers affecting infrasonic propagation within the diffraction zone. Recognition of these regional atmospheric patterns is necessary to permit robust infrasonic remote sensing of volcanic processes.
Melting of floating ice and sea level rise
Authors: Jenkins Adrian , Holland David
Published: August 2007

Contrary to popular belief, the melting of floating ice (in the form of ice shelves, icebergs and sea ice) may have a non‐zero impact on sea level. This is because the melting process cools and dilutes the oceans on average, and unless these opposing effects exactly balance each other there will be a net change in the ocean density. We discuss how these subtle effects can be quantified and put bounds on the potential sea level rise associated with melting of the ice masses that are currently afloat in the world's oceans.
Slot region electron loss timescales due to plasmaspheric hiss and lightning‐generated whistlers
Authors: Meredith Nigel P. , Horne Richard B. , Glauert Sarah A. , Anderson Roger R.
Published: August 2007

Energetic electrons (E > 100 keV) in the Earth's radiation belts undergo Doppler‐shifted cyclotron resonant interactions with a variety of whistler mode waves leading to pitch angle scattering and subsequent loss to the atmosphere. In this study we assess the relative importance of plasmaspheric hiss and lightning‐generated whistlers in the slot region and beyond. Electron loss timescales are determined using the Pitch Angle and energy Diffusion of Ions and Electrons (PADIE) code with global models of the spectral distributions of the wave power based on CRRES observations. Our results show that plasmaspheric hiss propagating at small and intermediate wave normal angles is a significant scattering agent in the slot region and beyond. In contrast, plasmaspheric hiss propagating at large wave normal angles and lightning‐generated whistlers do not contribute significantly to radiation belt loss. The loss timescale of 2 MeV electrons due to plasmaspheric hiss propagating at small and intermediate wave normal angles in the center of the slot region (L = 2.5) lies in the range 1–10 days, consistent with recent Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX) observations. Wave turbulence in space, which is responsible for the generation plasmaspheric hiss, thus leads to the formation of the slot region. During active periods, losses due to plasmaspheric hiss may occur on a timescale of 1 day or less for a wide range of energies, 200 keV < E < 1 MeV, in the region 3.5 < L < 4.0. Plasmaspheric hiss may thus also be a significant loss process in the inner region of the outer radiation belt during magnetically disturbed periods.
Dust plumes over the Pacific, Indian, and Atlantic oceans: Climatology and radiative impact
Authors: Zhu Aihua , Ramanathan V. , Li Fang , Kim Dohyeong
Published: August 2007

Multiple satellite data sets in conjunction with the Monte Carlo Aerosol‐Cloud‐Radiation (MACR) model are employed to determine climatological distributions and radiative impacts of dust plumes over the Pacific, Indian, and Atlantic oceans. Three target regions, namely the Yellow Sea (YS), Arabian Sea (AS), and Saharan Coast (SC), are examined for quantitative comparisons of dust properties and their impacts on climate. Twenty year averaged Advanced Very High Resolution Radiometer (AVHRR) aerosol optical depth (AOD) data clearly show the peak dust season for the three target regions, March–April–May for YS and June–July–August for AS and SC. Georgia Institute of Technology–Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) modeled dust AOD fraction and Moderate Imaging Spectroradiometer (MODIS) large‐mode AOD ratio are adopted to evaluate the dust fraction estimate. Stratospheric Aerosol and Gas Experiment (SAGE) II aerosol extinction coefficient data are used to define the vertical distribution of dust. The elevated dust plumes are detected by subtracting the non‐dust‐season values from dust season values of SAGE II data, showing extinction peak around ∼4 km over AS and SC. Over YS, dust plumes are found presenting multilayered structure. The shortwave (SW) forcing of dust, although moderated by the longwave (LW) effect, dominates the net effects (SW + LW) of dust plumes. Under clear‐sky (i.e., cloudless) conditions, dust plumes reduce about 5.9 W m−2, 17.8 W m−2, and 14.2 W m−2 regional and seasonal mean radiative flux reaching the surface over YS, AS, and SC, respectively. Of the three regions, dust plumes over AS have the largest effect on atmospheric heating owing to a lower single‐scattering albedo and the relatively large dust loading. The maximum SW heating occurs over AS with the value around +0.5 K/day inside the dust layer at ∼4 km. The LW effect results in strong cooling throughout the dust layer and moderate heating below the dust layer, and dust plumes over SC exert the maximum LW effect on heating rates, with up to −0.5 K/day LW cooling in the free troposphere and about +0.3 K/day warming in the boundary layer. As the sum of the SW and the LW heating rates, net heating rate shows a more complex pattern. Over SC, large LW cooling inside the dust layer offsets up to 80% SW heating and results in about −0.1 K/day net heating rate change at the height ∼5 km over SC. Over AS the net heating rate change is dominated by SW heating because the maximum LW cooling is less than 60% of the SW heating, which leads to +0.3 K/day net heating inside the dust layer and moderate heating below the dust base. The net heating rate change over YS is the smallest among the three regions, with magnitude within 0.1 K/day.
A proposed working standard for the measurement of diffuse horizontal shortwave irradiance
Authors: Michalsky J. J. , Gueymard C. , Kiedron P. , McArthur L. J. B. , Philipona R. , Stoffel T.
Published: August 2007

Atmospheric radiative transfer model estimates of diffuse horizontal broadband shortwave (solar) irradiance have historically been larger than measurements from a shaded pyranometer. A reference standard for the diffuse horizontal shortwave irradiance does not exist. There are no current efforts to develop an absolute standard that are known to the authors. This paper presents the case for a working standard for this measurement. Four well‐behaved pyranometers from two previous intensive observation periods (IOP) were chosen for this study. The instruments were characterized for spectral and angular response before the IOP and calibrated during the IOP using a shade/unshade technique with reference direct irradiance from an absolute cavity radiometer. The results of the comparison and detailed analyses to explain the differences suggest selecting three of the four for the working standard. The 95% confidence uncertainty in this standard is estimated at 2.2% of reading + 0.2 W/m2. In lieu of a comparison to this trio, a procedure for obtaining low‐uncertainty diffuse horizontal shortwave irradiance is suggested.
Mineralogical structure of the subsurface of Syrtis Major from OMEGA observations of lobate ejecta blankets
Authors: Baratoux D. , Pinet P. , Gendrin A. , Kanner L. , Mustard J. , Daydou Y. , Vaucher J. , Bibring J.‐P.
Published: August 2007

This paper focuses on the spectral characteristics of lobate ejecta across Syrtis Major volcano, a dark region of Mars presenting a mafic composition as revealed from the Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité (OMEGA) instrument. Two spectrally distinct crater types are identified. Type I is enriched in high‐calcium pyroxene (HCP) relative to the volcanic rocks. Type II is similar to the lava flow mineralogy driven by HCP, compared to the Noachian crust dominated by low‐calcium pyroxene (LCP). Type I craters are systematically younger than type II. The type II mineralogy has been likely affected by a long‐term weathering in a cold environment for the last 2 Ga. The axisymmetric spectral signatures of type I ejecta appear dominated by rock‐forming minerals rather than by soils and reflect the composition of excavated materials offering a window for exploring the subsurface. A progressive change in the slope of the spectra around 1.5–2 μm is observed across the ejecta layers, pointing at a change in the HCP/LCP ratio. The deconvolution of the spectra by the Modified Gaussian Model unravels a maximum of HCP/LCP band strength ratio located between 1.2 and 3 crater radii for all type I craters. Using Z‐modeling, this observation translates into a maximum in the HCP/LCP abundances at a few hundreds of meters depth and suggests a homogeneous subsurface structure of the volcanic edifice. Below this horizon the HCP/LCP decrease may reveal a more ancient lava composition or the signature of the underlying Noachian crust.
Enhanced transmission through quasirandom nanostructured dielectric interfaces via supercritical angle scattering
Authors: Riyopoulos S. , Moustakas T. D. , Cabalu J. S.
Published: August 2007

Greatly enhanced radiation extraction has been observed through randomly textured interfaces with feature sizes comparable to the wavelength. Ray tracing fails in this regime and a different analytic treatment is presented based on supercritical scattering. A quasiperiodic interface destroys the k∥ invariance, introducing wave numbers shifted by structure period harmonics, and allows transmission for supercritical incidence. Converting the interface boundary conditions into effective current source terms yield simple integral formulas for the transmitted fraction including quasiperiodic, subwavelength surface features with random variation of the feature size and period. Supercritical transmission occurs for single monochromatic wave incidence, regardless of the angle, causing enhanced radiation extraction. Further enhancement follows from multiple bounces between opposed surfaces. The role of phase diffusion during multiple reflections is also addressed.
Electronic and quantum dynamical insight into the ultrafast proton transfer of 1-hydroxy-2-acetonaphthone
Authors: Ortiz-Sánchez Juan Manuel , Gelabert Ricard , Moreno Miquel , Lluch José M.
Published: August 2007

The ultrafast proton-transfer dynamics of 1-hydroxy-2-acetonaphthone has been theoretically analyzed in the ground and first singlet excited electronic states by density functional theory calculations and quantum dynamics. The potential energies obtained in the ground electronic state reveal that the proton-transfer process does not lead to a stable keto tautomer unless the transfer of the hydrogen from the enol form is accompanied by an internal rotation of the newly formed O–H bond. Calculations in the first singlet excited electronic state point to a very low barrier for the formation of the keto tautomer. The analysis of the calculated frequencies of the two tautomers in the excited state unveils a coupling of the skeletal motions (low frequency modes) with the proton-transfer process, as it has been stated from time-resolved experiments. The electronic energies obtained by the time-dependent density functional theory formalism have been fitted to a monodimensional potential energy surface in order to perform an exact quantum dynamics study of the process. Our results show that the proton-transfer process is completed within 25.5fs, in remarkable good agreement with experiments.
Solid phase thermodynamic perturbation theory: Test and application to multiple solid phases
Authors: Zhou Shiqi
Published: August 2007

A simple procedure for the determination of hard sphere (HS) solid phase radial distribution function (rdf) is proposed, which, thanks to its physical foundation, allows for extension to other crystal structures besides the fcc structure. The validity of the procedure is confirmed by comparing (1) the predicted HS solid phase rdf’s with corresponding simulation data and (2) the predicted non-HS solid phase Helmholtz free energy by the present solid phase first-order thermodynamic perturbation theory (TPT) whose numerical implementation depends on the HS solid phase rdf’s as input, with the corresponding predictions also by the first-order TPT but the required HS solid phase rdf is given by an “exact” empirical simulation-fitted formula. The present solid phase first-order TPT predicts isostructural fcc-fcc transition of a hard core attractive Yukawa fluid, in very satisfactory agreement with the corresponding simulation data and is far more accurate than a recent thermodynamically consistent density functional perturbation theory. The present solid phase first-order TPT is employed to investigate multiple solid phases. It is found that a short-ranged potential, even if it is continuous and differentiable or is superimposed over a long-ranged potential, is sufficient to induce the multiple solid phases. When the potential range is short enough, not only isostructural fcc-fcc transition but also isostructural bcc-bcc transition, simple cubic (sc)-sc transition, or even fcc-bcc, fcc-sc, and bcc-sc transitions can be induced. Even triple point involving three solid phases becomes possible. The multiple solid phases can be stable or metastable depending on the potential parameters.
Spectroscopy of ultrathin epitaxial rutile TiO2(110) films grown on W(100)
Authors: Bennett R. A. , Mulley J. S. , Newton M. A. , Surman M.
Published: August 2007

Epitaxial ultrathin titanium dioxide films of 0.3to∼7nm thickness on a metal single crystal substrate have been investigated by high resolution vibrational and electron spectroscopies. The data complement previous morphological data provided by scanned probe microscopy and low energy electron diffraction to provide very complete characterization of this system. The thicker films display electronic structure consistent with a stoichiometric TiO2 phase. The thinner films appear nonstoichiometric due to band bending and charge transfer from the metal substrate, while work function measurements also show a marked thickness dependence. The vibrational spectroscopy shows three clear phonon bands at 368, 438, and 829cm−1 (at 273K), which confirms a rutile structure. The phonon band intensity scales linearly with film thickness and shift slightly to lower frequencies with increasing temperature, in accord with results for single crystals.
A Langevin dynamics simulation study of the tribology of polymer loop brushes
Authors: Yin Fang , Bedrov Dmitry , Smith Grant D. , Kilbey S. Michael
Published: August 2007

The tribology of surfaces modified with doubly bound polymer chains (loops) has been investigated in good solvent conditions using Langevin dynamics simulations. The density profiles, brush interpenetration, chain inclination, normal forces, and shear forces for two flat substrates modified by doubly bound bead-necklace polymers and equivalent singly bound polymers (twice as many polymer chains of 12 the molecular weight of the loop chains) were determined and compared as a function of surface separation, grafting density, and shear velocity. The doubly bound polymer layers showed less interpenetration with decreasing separation than the equivalent singly bound layers. Surprisingly, this difference in interpenetration between doubly bound polymer and singly bound polymer did not result in decreased friction at high shear velocity possibly due to the decreased ability of the doubly bound chains to deform in response to the applied shear. However, at lower shear velocity, where deformation of the chains in the flow direction is less pronounced and the difference in interpenetration is greater between the doubly bound and singly bound chains, some reduction in friction was observed.
Modeling RedOx-based magnetohydrodynamics in three-dimensional microfluidic channels
Authors: Kabbani Hussameddine , Wang Aihua , Luo Xiaobing , Qian Shizhi
Published: August 2007

RedOx-based magnetohydrodynamic (MHD) flows in three-dimensional microfluidic channels are investigated theoretically with a coupled mathematical model consisting of the Nernst-Planck equations for the concentrations of ionic species, the local electroneutrality condition for the electric potential, and the Navier-Stokes equations for the flow field. A potential difference is externally applied across two planar electrodes positioned along the opposing walls of a microchannel that is filled with a dilute RedOx electrolyte solution, and a Faradaic current transmitted through the solution results. The entire device is positioned under a magnetic field which can be provided by either a permanent magnet or an electromagnet. The interaction between the current density and the magnetic field induces Lorentz forces, which can be used to pump and/or stir fluids for microfluidic applications. The induced currents and flow rates in three-dimensional (3D) planar channels obtained from the full 3D model are compared with the experimental data obtained from the literature and those obtained from our previous two-dimensional mathematical model. A closed form approximation for the average velocity (flow rate) in 3D planar microchannels is derived and validated by comparing its predictions with the results obtained from the full 3D model and the experimental data obtained from the literature. The closed form approximation can be used to optimize the dimensions of the channel and to determine the magnitudes and polarities of the prescribed currents in MHD networks so as to achieve the desired flow patterns and flow rates.
Reversible self-assembly of patchy particles into monodisperse icosahedral clusters
Authors: Wilber Alex W. , Doye Jonathan P. K. , Louis Ard A. , Noya Eva G. , Miller Mark A. , Wong Pauline
Published: August 2007

We systematically study the design of simple patchy sphere models that reversibly self-assemble into monodisperse icosahedral clusters. We find that the optimal patch width is a compromise between structural specificity (the patches must be narrow enough to energetically select the desired clusters) and kinetic accessibility (they must be sufficiently wide to avoid kinetic traps). Similarly, for good yields the temperature must be low enough for the clusters to be thermodynamically stable, but the clusters must also have enough thermal energy to allow incorrectly formed bonds to be broken. Ordered clusters can form through a number of different dynamic pathways, including direct nucleation and indirect pathways involving large disordered intermediates. The latter pathway is related to a reentrant liquid-to-gas transition that occurs for intermediate patch widths upon lowering the temperature. We also find that the assembly process is robust to inaccurate patch placement up to a certain threshold and that it is possible to replace the five discrete patches with a single ring patch with no significant loss in yield.
Theoretical and infrared spectroscopic investigation of the O2−∙benzene and O4−∙benzene complexes
Authors: Schneider Holger , Weber J. Mathias , Myshakin Evgeniy M. , Jordan Kenneth D. , Bopp Joseph , Herden Tobias , Johnson Mark A.
Published: August 2007

The infrared spectra of the O2−∙benzene and O4−∙benzene complexes are determined by means of Ar predissociation spectroscopy. Several transitions due to CH stretch fundamentals and various combination bands are observed in the 2700–3100cm−1 region. The experimental results are interpreted with the aid of electronic structure calculations. A comparison of the calculated and experimental spectra reveals that the spectrum of O2−∙benzene most likely arises from an isomer where the superoxide molecule binds preferentially to one CH group of benzene. In contrast, the spectrum of O4−∙benzene yields a CH pattern remarkably similar to that displayed by the C2ν X−∙benzene (X=halogen) complexes, consistent with a structure with two CH groups equally involved in the bonding. The lower energy vibrational fundamental transitions of the O4− anion are recovered with a slight redshift in the O4−∙benzene spectrum, establishing that this charge-delocalized dimer ion retains its identity upon complexation.
Semiclassical description of electronically nonadiabatic dynamics via the initial value representation
Authors: Ananth Nandini , Venkataraman Charulatha , Miller William H.
Published: August 2007

The initial value representation (IVR) of semiclassical (SC) theory is used in conjunction with the Meyer-Miller/Stock-Thoss description of electronic degrees of freedom in order to treat electronically nonadiabatic processes. It is emphasized that the classical equations of motion for the nuclear and electronic degrees of freedom that emerge in this description are precisely the Ehrenfest equations of motion (the force on the nuclei is the force averaged over the electronic wave function) but that the trajectories given by these equations of motion do not have the usual shortcomings of the traditional Ehrenfest model when they are used within the SC-IVR framework. For example, in the traditional Ehrenfest model (a mixed quantum-classical approach) the nuclear motion emerges from a nonadiabatic encounter on an average potential energy surface (a weighted average according to the population in the various electronic states), while the SC-IVR describes the correct correlation between electronic and nuclear dynamics, i.e., the nuclear motion is on one potential energy surface or the other depending on the electronic state. Calculations using forward-backward versions of SC-IVR theory are presented to illustrate this behavior. An even more approximate version of the SC-IVR, the linearized approximation (LSC-IVR), is slightly better than the traditional Ehrenfest model, but since it cannot describe quantum coherence effects, the LSC-IVR is also not able to describe the correct correlation between nuclear and electronic dynamics.
Infrared surface plasmon resonances due to Er-V semimetallic nanoparticles in III-V semiconductor matrices
Authors: Hanson M. P. , Gossard A. C. , Brown E. R.
Published: August 2007

Absorption resonances attributed to surface plasmons are observed in various Er-V nanoparticle/III-V semiconductor superlattices grown by molecular beam epitaxy. ErAs particles in GaAs and GaAs0.5Sb0.5 as well as ErSb particles in GaSb and GaAs0.5Sb0.5 are investigated. Transmission measurements indicate resonant absorption peaks from 1.2to2.4μm depending on growth conditions for ErAs particles in GaAs. In the case of ErSb particles in GaSb these features are observed from about 2.4to4.5μm. For the ErAs or ErSb particles grown in GaAs0.5Sb0.5 the resonances were found to straddle the band gap of the semiconductor matrix around 1.5μm. Growth conditions are used to engineer the nanoparticles’ shape and density in order to tune the wavelength and intensity of the resonance. The asymmetry of the ErSb particles, which preferentially elongate along the [01¯1] direction, leads to a dependence of the resonance on polarization of the incident light. The absorption peak for light polarized parallel to the long axis of the particles is found to occur at longer wavelengths than those for that for light polarized perpendicular to the long axis of the particles.
Co doping effect on the magnetic properties of CeO2 films on Si(111) substrates
Authors: Song Y. Q. , Zhang H. W. , Wen Q. Y. , Zhu Hao , Xiao John Q.
Published: August 2007

Ce 1 − x Co x O 2 − δ films with the stoichiometry of x=0,0.03,0.06,0.1,0.125 were fabricated on Si(111) substrates using O2 assisted pulse laser deposition method. While pure CeO2 film is weak paramagnetism, integration of low Co content of 3at.% introduces ferromagnetim with a giant saturation moment (Ms) of 5μB∕Co at room temperature. Based on the first principle calculation, we attribute the giant magnetic moments to the combined contributions of spin polarized Co, Ce, and O atom with the enhancement of O vacancies. Higher Co content will depress the ferromagnetism, i.e., inverse correlation between Ms and Co contents, which is qualitatively validated by the calculated magnetic moments of Ce1−xCoxO2−δ with different Co content.