bluuebunny/crossref_metadata_2025 huggingface dataset:
Sydney Principles’ for reducing the commercial promotion of foods and beverages to children
Authors: Swinburn Boyd , Sacks Gary , Lobstein Tim , Rigby Neville , Baur Louise A , Brownell Kelly D , Gill Tim , Seidell Jaap , Kumanyika Shiriki
Published: May 2008

A set of seven principles (the ‘Sydney Principles’) was developed by an International Obesity Taskforce (IOTF) Working Group to guide action on changing food and beverage marketing practices that target children. The aim of the present communication is to present the Sydney Principles and report on feedback received from a global consultation (November 2006 to April 2007) on the Principles.

The Principles state that actions to reduce marketing to children should: (i) support the rights of children; (ii) afford substantial protection to children; (iii) be statutory in nature; (iv) take a wide definition of commercial promotions; (v) guarantee commercial-free childhood settings; (vi) include cross-border media; and (vii) be evaluated, monitored and enforced.

The draft principles were widely disseminated and 220 responses were received from professional and scientific associations, consumer bodies, industry bodies, health professionals and others. There was virtually universal agreement on the need to have a set of principles to guide action in this contentious area of marketing to children. Apart from industry opposition to the third principle calling for a statutory approach and several comments about the implementation challenges, there was strong support for each of the Sydney Principles. Feedback on two specific issues of contention related to the age range to which restrictions should apply (most nominating age 16 or 18 years) and the types of products to be included (31 % nominating all products, 24 % all food and beverages, and 45 % energy-dense, nutrient-poor foods and beverages).

The Sydney Principles, which took a children’s rights-based approach, should be used to benchmark action to reduce marketing to children. The age definition for a child and the types of products which should have marketing restrictions may better suit a risk-based approach at this stage. The Sydney Principles should guide the formation of an International Code on Food and Beverage Marketing to Children.
THE COMPLEX INVERSION FORMULA REVISITED
Authors: HAASE MARKUS
Published: May 2008

We give a simplified proof of the complex inversion formula for semigroups and, more generally, solution families for scalar-type Volterra equations, including the stronger versions on unconditional martingale differences (UMD) spaces. Our approach is based on (elementary) Fourier analysis.
A NOTE ON THE CLOSURE OF CONVOLUTION POWER MIXTURES (RANDOM SUMS) OF EXPONENTIAL DISTRIBUTIONS
Authors: ALBIN J. M. P.
Published: May 2008

We make a correction to an important result by Cline [D. B. H. Cline, ‘Convolutions of distributions with exponential tails’, J. Austral. Math. Soc. (Series A)43 (1987), 347–365; D. B. H. Cline, ‘Convolutions of distributions with exponential tails: corrigendum’, J. Austral. Math. Soc. (Series A)48 (1990), 152–153] on the closure of the exponential class $\mathcal {L}(\alpha )$ under convolution power mixtures (random summation).
DIFFERENCES OF COMPOSITION OPERATORS BETWEEN WEIGHTED BANACH SPACES OF HOLOMORPHIC FUNCTIONS
Authors: BONET JOSÉ , LINDSTRÖM MIKAEL , WOLF ELKE
Published: May 2008

We consider differences of composition operators between given weighted Banach spaces$H_v^{\infty }$orHv0of analytic functions with weighted sup-norms and give estimates for the distance of these differences to the space of compact operators. We also study boundedness and compactness of the operators. Some examples illustrate our results.
ORBIFOLDS ARE NOT COMMUTATIVE GEOMETRIES
Authors: RENNIE ADAM , VÁRILLY JOSEPH C.
Published: May 2008

In this note we show that the crucial orientation condition for commutative geometries fails for the natural commutative spectral triple of an orbifold M/G.
Soil nutrient and plant responses to solarization in an agroecosystem utilizing an organic nutrient source
Authors: Seman-Varner R. , McSorley R. , Gallaher R.N.
Published: May 2008

Soil solarization is used to manage nematodes, pathogens and weeds, but relatively few studies have examined solarization effects on soil mineral nutrients, soil properties and plant tissue nutrients. This study was designed to optimize the duration of solarization treatment for the management of soil and plant nutrients and crop biomass in an agroecosystem utilizing an organic nutrient source. The experiment was a split-plot with treatment duration as the main effect and solarization as the sub-effect. Solarization treatments of 2-, 4- and 6-week durations began on sequential dates and concluded in mid-August. Immediately post-treatment, okra (Hibiscus esculentus L.) seedlings were transplanted into subplots for tissue nutrient analysis. Freshly chopped cowpea [Vigna unguiculata (L.) Walp.] hay was applied to the soil surface directly around the okra seedlings as an organic nutrient source. Immediately following solarization treatment, concentrations of soil K and Mn were higher, while Cu and Zn concentrations were lower in solarized soils than in non-solarized soils. Soil pH was slightly lower in solarized plots. Concentrations of K, N, Mg and Mn in okra leaf tissue were higher in solarized plots than in non-solarized plots, but concentrations of P and Zn were lower in plants grown in solarized soil. Okra biomass was three and four times higher in the 4- and 6-week solarization treatments than in non-solarized treatments. Based on data from this experiment, 4- and 6-week durations of solarization were optimal for increasing crop biomass. The data indicate that solarization has significant effects on soil and plant nutrients. Results of the nutrient analyses suggest that the availability of nutrients from an organic source was not limited by solarization.
Effects of soil fungi on weed communities in a corn–soybean rotation
Authors: Jordan N. , Huerd S.
Published: May 2008

In a variety of ecosystems, interactions between soil microbiota and weedy plants can strongly affect population and community dynamics of these plants. However, weed–soil microbe interactions are not well characterized in field-crop agroecosystems. In Minnesota (USA), we repeatedly applied a fungicide (benomyl) to field plots in a corn–soybean crop rotation in each of 3 years, and sowed experimental weed communities containing host species for arbuscular-mycorrhizal fungi (AMF) and non-host species. Benomyl typically suppresses formation of mycorrhizal symbiosis in AMF-host plant species, and may also affect other soil fungi. We assessed weed density and biomass production, and monitored AMF colonization rates in each of 3 years. We found that weed density, biomass, community composition and the relative performance of AMF-host and non-host weed species were all significantly responsive to fungicide applications, although for all attributes responsiveness was variable. Fungicide application increased total weed density and biomass production in nearly all cases; most effects were modest but reached a maximum of 49%. Fungicide application also increased the relative performance of non-host species in most cases, although most effects were again modest. Our findings are the first assessment of responses by field-crop weeds to direct manipulation of soil microbial communities in a field setting, and suggest that the population and community ecology of these weeds can be strongly affected by the fungal component of soil microbiota.
Structure, Empowerment and the Liberalization of Cross-National Abortion Rights
Authors: Asal Victor , Brown Mitchell , Figueroa Renee Gibson
Published: May 2008

Economic, cultural, and political opportunity structures have been separately shown to facilitate and constrain abortion rights. We examine two central and related questions: First, which factors explain liberalization of different types of abortion laws? Second, which factor or set of factors is the most important in explaining abortion laws? The cross-national literature suggests a three-pronged explanation for the existence of abortion rights, including politics, economics, and culture. We parse these out into the structural and empowerment components of each, and posit a theory of rights in which empowerment factors are at least as important, if not more important, for explaining change than structural factors. To test this, we examine the impact of these components on the liberalization of abortion rights globally utilizing a distributed lag model. We find that an empowerment approach explains the liberalization of abortion laws better than a structural approach in terms of politics, but that a structural approach is a better predictor in terms of culture, and that both empowerment and structural factors are important predictors when economic factors are taken into account. We conclude with a discussion of the implications of these findings for understanding policy change and human rights on a global scale.
A Gendered Pipeline? The Advancement of State Legislators to Congress in Five States
Authors: Mariani Mack D.
Published: May 2008

The pipeline theory predicts that women serving in lower levels of political office will leverage political resources and experience gained at those levels to advance to higher office. On the basis of this theory, several prominent scholars have predicted that the election of increasing numbers of women to state legislatures will result in proportionate increases in women's representation in Congress. This study analyzes patterns of congressional advancement among state legislators in five states and finds that female state legislators are less likely to advance to Congress than their male colleagues. There are gender-related differences in the occupational backgrounds and family situations that hinder the advancement of female state legislators to Congress. In addition, female legislators are older and less likely to have a background in the “springboard” professions of business or law. Given these findings, the pipeline theory should be refined to better account for the impact of gender-based differences on congressional advancement.
Difference and Social Structure: Iris Young's Legacy of a Critical Social Theory of Gender
Authors: Weldon S. Laurel
Published: May 2008

Iris Young was a wide-ranging political and social theorist whose works transformed the study of democratic theory, theories of justice, multiculturalism, nationalism, and group rights, among others—all of this in addition to her enormous contribution to feminist theory. Young left not only specific substantive legacies but also her method as a critical social theorist: She sought to undertake projects that helped make sense of the claims and analyses made by progressive social movements, including feminist movements, by providing a philosophical grounding for those claims and analyses. She trained her critical eye on political and social institutions, aiming to expose relations of domination and other injustices.
Suicide attacks and Islamic law
Authors: Munir Muhammad
Published: May 2008

Suicide attacks are a recurrent feature of many conflicts. Whereas warfare heroism and martyrdom are allowed in certain circumstances in times of war, a suicide bomber might be committing at least five crimes according to Islamic law, namely killing civilians, mutilating their bodies, violating the trust of enemy soldiers and civilians, committing suicide and destroying civilian objects or properties. The author examines such attacks from an Islamic jus in bello perspective.
Human rights in Iraq's transition: the search for inclusiveness
Authors: Pace John P.
Published: May 2008

The aftermath of the invasion of Iraq set unprecedented challenges to the United Nations in the political and in the human rights spheres. Since the first involvement of the United Nations under Security Council Resolution 1483 (2003), the United Nations, through its assistance mission (UNAMI), has provided support to the process of transition from a military occupation resulting from an unlawful invasion to a fully sovereign and independent state, an objective yet to be fully achieved. The article looks at this trajectory from the angle of the involvement of the Security Council, the legal context, the protection of human rights and the striving for reconciliation, sovereignty and inclusiveness.
The ethos–practice gap: perceptions of humanitarianism in Iraq
Authors: Hansen Greg
Published: May 2008

This article summarizes a country study on Iraq conducted by the Humanitarian Agenda: 2015 project of the Feinstein International Center, Tufts University, between October 2006 and May 2007.* Based on a sample survey of perceptions of humanitarian action among Iraqis at the community level and among humanitarian agencies in the region, the study focuses on what Iraqis and aid workers believe to be true about the way in which the humanitarian apparatus has functioned or malfunctioned in Iraq, and why. Its findings confirm both the strength of the humanitarian ethos in Iraq and the operational value of principled humanitarianism, but call attention to significant gaps at ground level between ethos and practice.
Ethnicity, federalism and the idea of sectarian citizenship in Iraq: a critique
Authors: Visser Reidar
Published: May 2008

The article discusses the “ethnic paradigm” that currently prevails in analyses of Iraqi history and politics. While acknowledging the strong forces associated with ethnic and sectarian loyalties in the country, the article points to three important indicators of the surviving Iraqi nationalist sentiment that cut across these ethno-sectarian categories. It highlights the misfit between Western approaches to Iraqi politics and indigenous Iraqi political thinking on ethnicity and sectarianism, and pays special attention to the implications for the debates about federalism and the partitioning – “soft” or “hard” – of Iraq.
Crossing the desert – the ICRC in Iraq: analysis of a humanitarian operation
Authors: Palmieri Daniel
Published: May 2008

For almost 60 years, the International Committee of the Red Cross (ICRC) has been doing its best to provide humanitarian assistance to those groups in Iraq that need it most. This article describes the humanitarian operations of the ICRC in Iraq from 1950 to the present day, in particular the support it has given to different minorities in the country and its humanitarian responses to the various armed conflicts. It shows that the legal framework that provides the basis for the ICRC's humanitarian activities also limits its ability to take action in situations beyond the scope of its mandate. In armed conflicts the ICRC faces the risk of being used by governments for their own ends. The challenge for the ICRC is to strike a balance between meeting its treaty-based obligations and exercising its right of humanitarian initiative, and to avoid selecting the recipients of its aid on the sole basis of opportunities made available by governments.
The crisis of professional responsibility in Iraqi journalism: avoiding incitement to violence and armed conflict
Authors: Abdel Majid Ahmad
Published: May 2008

This article proposes that the current journalistic challenges in Iraq necessitate, inter alia, a commitment by journalists to their professional responsibility, since this will guarantee the avoidance of the danger of sliding into the implications that usually result from armed sectarian conflicts. This responsibility should be exercised to assist the victims and promote a spirit of tolerance and reconciliation through the principles of professional ethics based on balance, equity, accuracy and objectivity. It might not be possible to achieve this without a code, agreed upon by all, which persons working in the journalistic profession would apply in a manner consistent with the fundamental principles of professional journalism, which require emotional detachment when formulating the content of news reports. The author proposes a preliminary theory or vision that could be modified or discussed in order to achieve this purpose in a country that is suffering, and will continue to suffer, from merciless bloodshed.
Wartime estimates of Iraqi civilian casualties
Authors: Daponte Beth Osborne
Published: May 2008

Challenges exist when making reliable and valid estimates of civilian mortality due to war. This article first discusses a framework used to examine war's impact on civilians and then considers challenges common to each statistical approach taken to estimate civilian casualties. It examines the different approaches that have been used to estimate civilian casualties associated with the recent fighting in Iraq to date and compares the results of different approaches. The author concludes by proposing that after fighting has ceased, other approaches to estimating Iraqi civilian mortality, such as post-war retrospective surveys and demographic analysis, should be employed.
A neutral, impartial and independent approach: key to ICRC's acceptance in Iraq
Authors: Mattli Karl , Gasser Jörg
Published: May 2008

The article describes the context of the ICRC's operations in Iraq, where the Iran–Iraq War in the 1980s, the Gulf War in 1990–1 and the effects of sanctions preceded the 2003 conflict and the spread of sectarian violence. The many serious attacks, including the bombing of the ICRC delegation in Baghdad in 2003 and continuing threats to the ICRC delegates, led to a low-visibility presence and required a new modus operandi in which a real presence on the ground was backed up by remote-control mechanisms for assistance activities in the most insecure areas. Projects to cover essential needs by ensuring water supplies and sewage disposal and supporting health facilities exemplify this new ICRC operational framework. Whereas remote control and support operations enabled programmes of increasing scope and size to be implemented, they could not replace a direct physical presence on the ground, and acceptance-building had to be reinforced through networking and communicational aspects. The authors argue, however, that there is still room for independent, neutral and impartial humanitarian action in Iraq – despite inherent security risks.
Stratification of lakes
Authors: Boehrer Bertram , Schultze Martin
Published: May 2008

Many lakes show vertical stratification of their water masses, at least for some extended time periods. Density differences in water bodies facilitate an evolution of chemical differences with many consequences for living organisms in lakes. Temperature and dissolved substances contribute to density differences in water. The atmosphere imposes a temperature signal on the lake surface. As a result, thermal stratification can be established during the warm season if a lake is sufficiently deep. On the contrary, during the cold period, surface cooling forces vertical circulation of water masses and removal of gradients of water properties. However, gradients of dissolved substances may be sustained for periods much longer than one annual cycle. Such lakes do not experience full overturns. Gradients may be a consequence of external inflows or groundwater seepage. In addition, photosynthesis at the lake surface and subsequent decomposition of organic material in the deeper layers of a lake can sustain a gradient of dissolved substances. Three more geochemical cycles, namely, calcite precipitation, iron cycle, and manganese cycle, are known for sustaining meromixis. A limited number of lakes do not experience a complete overturn because of pressure dependence of temperature of maximum density. Such lakes must be sufficiently deep and lie in the appropriate climate zone. Although these lakes are permanently stratified, deep waters are well ventilated, and chemical differences are small. Turbulent mixing and convective deep water renewal must be very effective. As a consequence, these lakes usually are not termed meromictic. Permanent stratification may also be created by episodic partial recharging of the deep water layer. This mechanism resembles the cycling of the ocean: horizontal gradients result from gradients at the surface, such as differential cooling or enhanced evaporation in adjacent shallow side bays. Dense water parcels can be formed which intrude the deep water layer. In the final section, stratification relevant physical properties, such as sound speed, hydrostatic pressure, electrical conductivity, and density, are discussed. The assumptions behind salinity, electrical conductance, potential density, and potential temperature are introduced. Finally, empirical and theoretical approaches for quantitative evaluation from easy to measure properties conclude this contribution.
The structure of the base of the outer core inferred from seismic waves diffracted around the inner core
Authors: Zou Zuihong , Koper Keith D. , Cormier Vernon F.
Published: May 2008

We systematically searched for seismograms of waves diffracted around the inner core (PKPCdiff) from all the temporary seismic arrays with data currently available at the IRIS DMC, as well as some permanent regional seismic arrays including F‐NET in Japan and GRF in Germany, to assemble the largest high‐quality PKPCdiff database ever created. PKPCdiff waves preferentially sample the base of the outer core and so contain important clues about Earth structure in this region. We measured PKPDF–PKPCdiff differential traveltimes and PKPCdiff/PKPDF amplitude ratios in the distance range of 154°–160° and modeled the observations using grid searches and full wave theory synthetic seismograms. The optimum model found by fitting the differential traveltimes has relatively low velocity at the base of the outer core as in AK135, which is consistent with many previous traveltime studies. However, the optimum model found by fitting the amplitude ratios (PKPCdiff/PKPDF) does not exhibit this feature, and instead is closer to PREM. The discrepancy may be explained by two likely causes. One is that small‐scale topography or roughness on the ICB tends to scatter energy away from PKPCdiff waves by generating trailing coda waves. The other is that there exists a thin layer with relatively low Q at the base of the outer core. This might be expected if there are suspended solid particles at the base of the outer core, as proposed decades ago. Both mechanisms could generate smaller PKPCdiff amplitudes without significantly affecting PKPCdiff traveltimes.
Ozonesonde observations at Christmas Island (2°N, 157°W) in the equatorial central Pacific
Authors: Takashima H. , Shiotani M. , Fujiwara M. , Nishi N. , Hasebe F.
Published: May 2008

Ozone and water vapor observations have been conducted at Christmas/Kiritimati Island (2°N, 157°W) in the equatorial central Pacific as a part of the Soundings of Ozone and Water in the Equatorial Region (SOWER)/Pacific mission. We launched 33 ozonesondes and 33 chilled‐mirror hygrometers in nine observation campaigns from 1999 to 2003 for various seasons. We found that ozone concentrations at Christmas Island are low in the whole troposphere (∼10–35 ppbv), particularly in the marine boundary layer (MBL). Ozone variation is small throughout the year compared with other tropical stations, though annual and interannual variations of meteorological fields are large over the equatorial central Pacific. Just below the tropopause, during the August 2002 campaign, we observed substantially reduced ozone concentrations (<10 ppbv) similar to those found in the MBL, which are maintained at least for the observation period. From meteorological conditions, we found that air mass was advected from the Inter‐Tropical Convergence Zone (ITCZ), located to the north of Christmas Island, in accordance with the northeasterly wind that is only observed during northern summer in the upper troposphere. The origin of air mass is supposed to be from the MBL in the ITCZ.
Benthic foraminiferal faunal and isotopic changes as recorded in Holocene sediments of the northwest Indian Ocean
Authors: Gupta Anil K. , Das Moumita , Clemens Steven C. , Mukherjee Baidehi
Published: May 2008

Historically, the Holocene has been considered an interval of relatively stable climate. However, recent studies from the northern Arabian Sea (Netherlands Indian Ocean Program 905) suggested high‐amplitude climate shifts in the early and middle Holocene based on faunal and benthic isotopic proxy records. We examined benthic foraminiferal faunal and stable isotopic data from Ocean Drilling Program (ODP) Site 723 and total organic carbon data from ODP Site 724, Oman Margin (808 and 593 m water depths, respectively). At Site 723 the mid‐Holocene shift in δ18O values of infaunal benthic species Uvigerina peregrina (1.4‰) is 3 times larger than that of epifaunal benthic species Cibicides kullenbergi recorded at Site NIOP 905 off Somalia. However, none of the five other benthic species we measured at Hole 723A exhibits such a shift in δ18O. We speculate that the late Holocene δ18O decrease in U. peregrina represents species‐specific changes in ecological habitat or food preference in response to changes in surface and deep ocean circulation. While the stable isotopic data do not appear to indicate a middle Holocene climatic shift, our total organic carbon and benthic faunal assemblage data do indicate that the early Holocene deep Arabian Sea was influenced by increased ventilation perhaps by North Atlantic Deep Water and/or Circumpolar Deep Water incursions into the Indian Ocean, leading to remineralization of organic matter and a relatively weak early Holocene oxygen minimum zone in the northwest Arabian Sea in spite of strong summer monsoon circulation.
Signal power distribution in time delay in Tokyo City experimental sites
Authors: Hayakawa M. , Katz D. , Blaunstein N.
Published: May 2008

This paper presents experiments carried out in the city of Tokyo in two types of built‐up environments. One environment is characterized by a straight‐crossing street plan with buildings randomly lining the streets and the terminal antennas located at the line of sight (LOS) and quasi‐LOS conditions along the streets. The second built‐up area is characterized by straight‐crossing streets with non‐LOS (NLOS) conditions caused by the railway station and administrative buildings surrounding the terminal antennas. The time delay signal strength distributions obtained experimentally are presented for both multipath urban channels These test experiments are used to study whether any propagation modeling can predict the time delay distribution of signal power. Our theoretical framework is based on the corresponding crossing‐street waveguide model taking into account the Poisson statistics for buildings randomly lining each street. The proposed analytical formulas are analyzed for different parameters of the built‐up terrain, such as the street width, the average height of buildings, the terminal antenna heights with respect to the rooftops of buildings lining a street, and the gaps (slits) between the buildings. Then a comparison between the proposed theoretical model and experimental data is presented, which indicates a satisfactory agreement between the theoretical and experimental prediction of signal power distribution in the time delay domain. So, our modeling can be used as a promising predictor for the time delay distribution in the microcellular propagation environment.
Modeling the arrival at Earth of the interplanetary shock following the 12 May 1997 solar event using HAFv2 and 3‐D MHD HHMS models
Authors: Smith Z. K. , Detman T. R. , Sun W. , Dryer M. , Deehr C. S. , Fry C. D.
Published: May 2008

The 12 May 1997 solar event is used to demonstrate the improvements that have been made in recent years in the accuracy of predicting, in the operational environment, the time of arrival at Earth of solar‐caused interplanetary shocks. This event provides a simple test case because it was both well isolated in time from other events and well documented, with the observation of a large flare (in optical and X‐ray), a large halo CME, metric type‐II radio burst and near‐Earth solar wind and interplanetary magnetic field data. The Hakamada‐Akasofu‐Fry model (version 2: HAFv2) near‐real‐time prediction gave an error of 31 h. Because the accuracy of predicted Sun‐to‐Earth transit times of such shocks depends both on the model and our ability to determine the proper inputs from available observations, we reexamined the predictions made for the 12 May event using inputs that could have been available in near‐real‐time, both with HAFv2 and a second, ensemble‐partnered solar wind prediction model, the 3‐D MHD Hybrid Heliospheric Model System (HHMS). We use updated methods of estimating the initial shock velocity (from Smith et al., 2005b) and examine the influence of the background solar wind. This reexamination reduced the error from the original 31 h to less than 4 h. Achieving near‐real‐time accuracies to this level would greatly enhance operations of technologies such as electrical power grids, satellite systems, and polar flight communications.
Taking the Temperature of Ecological Systems With Fiber Optics: Fiber Optic Distributed Temperature Sensing for Ecological Characterization; Blue River, Oregon, 10–15 September 2007
Authors: Selker John S.
Published: May 2008

Fiber‐optic distributed temperature sensing (DTS) is emerging as a powerful tool for hydrological and ecological observation over wide spatial and temporal scales. DTS instillations allow for the precise observation of temperature at each meter of fiber‐optic cables, with a precision of up to 0.01°C. The temperature is computed from the light backscattered following an intense laser pulse, and the location of each reading is determined by the arrival time of the pulse back to the central recording station. Because cables can exceed 10,000 meters in length, DTS holds the potential for transformative observation of diverse Earth processes.
Coe Receives 2007 Gilbert Award
Authors: Bogue Scott W. , Coe Robert S.
Published: May 2008

Robert S. Coe received the 2007 William Gilbert Award at the 2007 AGU Fall Meeting in San Francisco, Calif. The award recognizes outstanding and unselfish work in magnetism of Earth materials and of the Earth and planets.
How Much Will Precipitation Increase With Global Warming?
Authors: Lambert F. Hugo , Stine Alexander R. , Krakauer Nir Y. , Chiang John C. H.
Published: May 2008

The advent of meteorological satellites during the 1970s made possible the observation of the seasonally shifting patterns of global precipitation. It was not until recently, however, that the record could be considered long enough to investigate longer‐term trends and the relationship between global precipitation and global warming. Using data from the Special Sensor Microwave Imager (SSM/I) instrument, Wentz et al. [2007] reported that global mean precipitation increased at a rate of 7.4±2.6% per °C between 1987 and 2006.

Meanwhile, general circulation models (GCMs) used to predict climate change simulate twentieth‐ and 21st‐century mean precipitation increases of about 13% per °C [Held and Soden, 2006]. This difference seems surprising because some GCMs can adequately reproduce the much longer twentieth‐ century surface‐based land‐mean precipitation record [Lambert et al., 2005]. Global precipitation changes are tied to the surface energy budget through evaporation and to the tropospheric energy budget through condensation. Thus, if GCMs do underestimate global precipitation changes, the simulation of other climate variables will be affected.
Online Database for Atmospheric Observational Research
Authors: Sawyer Karyn , Serafin Robert
Published: May 2008

A new Internet‐accessible database of U.S. atmospheric science observing facilities and instrumentation, called the Facilities Assessment Database (FADB), is now available to the research community. The database contains pertinent information about all facilities and instrumentation available to researchers, including their locations, technical specifications, means for gaining access for research, lists of contact people, and, if applicable, the facilities' and instruments' stage of development relative to deployment‐ready condition.
Did unusually sunny skies help drive the record sea ice minimum of 2007?
Authors: Schweiger A. J. , Zhang J. , Lindsay R. W. , Steele M.
Published: May 2008

We conduct experiments with an ice‐ocean model to answer the question whether and to what degree unusually clear skies during the summer of 2007 contributed to the record sea ice extent minimum in the Arctic Ocean during September of 2007. Anomalously high pressure over the Beaufort Sea during summer 2007 appears associated with a strong negative cloud anomaly. This anomaly is two standard deviations below the 1980–2007 average established from a combination of two different satellite‐based records. Cloud anomalies from the MODIS sensor are compared with anomalies from the NCEP/NCAR reanalysis and are found in good agreement in spatial patterns and magnitude. However, these experiments establish that the negative cloud anomaly and increased downwelling shortwave flux from June through August did not contribute substantially to the record sea ice extent minimum. This finding eliminates one aspect of the unusual weather that may have contributed to the record minimum.
Nonlocal magnetorotational instability
Authors: Mikhailovskii A. B. , Lominadze J. G. , Galvão R. M. O. , Churikov A. P. , Kharshiladze O. A. , Erokhin N. N. , Amador C. H. S.
Published: May 2008

An analytical theory of the nonlocal magnetorotational instability (MRI) is developed for the simplest astrophysical plasma model. It is assumed that the rotation frequency profile has a steplike character, so that there are two regions in which it has constant different values, separated by a narrow transition layer. The surface wave approach is employed to investigate the MRI in this configuration. It is shown that the main regularities of the nonlocal MRI are similar to those of the local instability and that driving the nonaxisymmetric MRI is less effective than the axisymmetric one, also for the case of the nonlocal instability. The existence of nonlocal instabilities in nonmagnetized plasma is predicted.
Nonlinear waves in collisional dusty plasma
Authors: Pandey B. P. , Vladimirov S. V. , Samarian A.
Published: May 2008

The nonlinear wave propagation in collisional dusty plasma is investigated in the present work. When the electrons and ions are highly magnetized, i.e., when the Lorentz force acting on the plasma particles dominates its collision with the dust and charged dust remains weakly magnetized, the drift between the plasma and dust particles may significantly modify the wave characteristics of the medium. It is shown that when electrons and ions move approximately with the same bulk velocity, the large amplitude waves can be easily excited in such a collisional dusty medium and they can be described by derivative nonlinear Schrödinger equation. It is quite possible that the soliton solutions of the nonlinear equation may be useful in explaining the parsec scale structures in the astrophysical plasmas.
Onset of buoyancy-driven convection in a liquid-saturated cylindrical porous layer supported by a gas layer
Authors: Kim Min Chan , Song Kwang Ho , Choi Chang Kyun , Yeo Jong-Kee
Published: May 2008

A theoretical analysis of convective instability driven by buoyancy forces under the transient concentration fields is conducted in an initially quiescent, liquid-saturated, cylindrical porous layer with gas diffusion from below. Darcy’s law and Boussinesq approximation are used to explain the characteristics of fluid motion, and linear stability theory is employed to predict the onset of buoyancy-driven motion. Under the principle of exchange of stabilities, the stability equations are derived on the basis of the propagation theory and the dominant mode method, which have been developed in a self-similar boundary layer coordinate system. The present predictions suggest the critical Darcy–Rayleigh number RD, which is quite different from the previous ones. The onset time becomes smaller with increasing RD and follows the asymptotic relation derived in the infinite horizontal porous layer.
Femtosecond time-resolved photoelectron-photoion coincidence imaging of multiphoton multichannel photodynamics in NO2
Authors: Vredenborg Arno , Roeterdink Willem G. , Janssen Maurice H. M.
Published: May 2008

The multiphoton multichannel photodynamics of NO2 has been studied using femtosecond time-resolved coincidence imaging. A novel photoelectron-photoion coincidence imaging machine was developed at the laboratory in Amsterdam employing velocity map imaging and “slow” charged particle extraction using additional electron and ion optics. The NO2 photodynamics was studied using a two color pump-probe scheme with femtosecond pulses at 400 and 266nm. The multiphoton excitation produces both NO2+ parent ions and NO+ fragment ions. Here we mainly present the time dependent photoelectron images in coincidence with NO2+ or NO+ and the (NO+,e) photoelectron versus fragment ion kinetic energy correlations. The coincidence photoelectron spectra and the correlated energy distributions make it possible to assign the different dissociation pathways involved. Nonadiabatic dynamics between the ground state and the AB22 state after absorption of a 400nm photon is reflected in the transient photoelectron spectrum of the NO2+ parent ion. Furthermore, Rydberg states are believed to be used as “stepping” states responsible for the rather narrow and well-separated photoelectron spectra in the NO2+ parent ion. Slow statistical and fast direct fragmentation of NO2+ after prompt photoelectron ejection is observed leading to formation of NO++O. Fragmentation from both the ground state and the electronically excited aB23 and bA23 states of NO2+ is observed. At short pump probe delay times, the dominant multiphoton pathway for NO+ formation is a 3×400nm+1×266nm excitation. At long delay times (>500fs) two multiphoton pathways are observed. The dominant pathway is a 1×400nm+2×266nm photon excitation giving rise to very slow electrons and ions. A second pathway is a 3×400nm photon absorption to NO2 Rydberg states followed by dissociation toward neutral electronically and vibrationally excited NO(AΣ2,v=1) fragments, ionized by one 266nm photon absorption. As is shown in the present study, even though the pump-probe transients are rather featureless the photoelectron-photoion coincidence images show a complex time varying dynamics in NO2. We present the potential of our novel coincidence imaging machine to unravel in unprecedented detail the various competing pathways in femtosecond time-resolved multichannel multiphoton dynamics of molecules.
Morphology and electronic properties of metal organic molecular beam epitaxy grown ZnO on hydrogen passivated 6H-SiC(0001)
Authors: Andres Stefan , Pettenkofer Christian , Speck Florian , Seyller Thomas
Published: May 2008

Thin ZnO films were grown on hydrogen passivated 6H-SiC(0001) substrates by metal organic molecular beam epitaxy. The initial growth as well as the electronic properties of the growing interface were monitored by low electron diffraction and photoelectron spectroscopy (PES). From the PES intensities of the substrate and ZnO film a layered Frank-van-der-Merwe-like growth mode could be observed within the first 10nm. The ZnO films grow preferentially in (0001) direction and show a pronounced facetting in the {101¯2} direction. The experimentally determined band alignment reveals band offsets of ΔEVBM≈1.6eV and ΔECBM≈1.2eV between the valence and conduction bands, respectively. With growing ZnO thickness a band bending of about −0.51eV is observed in the SiC substrate.
Minimization of thermal jitter in a balanced comparator single flux quantum cell
Authors: Gordeeva Anna V. , Pankratov Andrey L.
Published: May 2008

The process of reproduction of single flux quantum pulses in a Josephson junction chain composed of a pulse generator, a balanced comparator, and a single Josephson junction is investigated. It is shown that the reproduction of single flux quantum pulses in such a chain is more stable and the mean and the standard deviation of switching time are minimal for the McCumber-Stewart parameter value from 0.5 to 1 and for a normalized clock generator current around 1.5. The influence of input and output inductances on the characteristics of a balanced comparator is investigated. The recommended value of the output inductance leading to smooth pulses and relatively small jitter is around unity.
Leakage mechanisms and potential performance of molecular-beam epitaxially grown GaInAsSb 2.4 μm photodiode detectors
Authors: Prineas J. P. , Yager J. , Seyedmohamadi S. , Olesberg J. T.
Published: May 2008

We report on the growth, processing, and characterization of uncoated, unpassivated GaInAsSb detector mesa photodiodes with a cutoff wavelength of 2.4 μm. We find peak room temperature specific detectivity value of 6×1010 cm Hz1/2/W and maximum zero-bias resistivity of 25 Ω cm2. The zero-bias resistivities of mesas with areas ranging from 502 μm2 to 1 mm2 were found to be limited by generation-recombination currents at mesa sidewalls. At low temperatures, devices were limited by Ohmic leakage, which is likely due to the formation of oxides on the sidewalls. After 6 months of aging, Ohmic leakage becomes the limiting factor at room temperature as well. Based on experimentally obtained material parameters in this and other studies, an upper limit D∗ and R0A were estimated for GaInAsSb materials and compared to those HgCdTe and InGaAs.
Evidence of nonparabolicity and size of wave function confined in In0.53Ga0.47As/In0.52Al0.48As multi quantum wells
Authors: Kotera Nobuo , Tanaka Koichi , Nakamura Hitoshi , Washima Mineo
Published: May 2008

Nonparabolicity of the conduction band in In0.53Ga0.47As was analyzed using nanoscale InGaAs/InAlAs multi quantum well structures. The nonparabolic effective mass was determined from a set of eigen-energies using a single finite-square-well model. Conduction-band eigen-energies were obtained by analyzing the interband optical transition spectra of photocurrent and photoreflectance. Regarding the conduction band effective mass, Kane’s theory was applicable over the wide range from 0 to 0.5 eV. Based on the theory, the size of the electron wave function was determined with the resolution of 0.1 nm. This method provides a direct means to determine the quantum well thickness.
Complete sets of elastic, dielectric, and piezoelectric properties of [001]-poled Pb(Zn1∕3Nb2∕3)O3–(6–7)%PbTiO3 single crystals of [110]-length cut
Authors: Shukla Rahul , Rajan Kalidindi Kotam , Gandhi Prasanna , Lim Leong-Chew
Published: May 2008

[001]-poled relaxor based ferroelectric Pb(Zn1∕3Nb2∕3)O3–(6–7)%PbTiO3 single crystals of [110]-length cut exhibit k31≈0.85 and very high d31∕s11E value. They are promising materials for sensors and actuators comprising an elastic substrate such as a metal shim or support, especially under dynamic loading conditions. In this work, the full sets of elastic, dielectric, and piezoelectric properties of [110]L×[001]T(P) single crystal are determined by means of the resonant technique. The obtained property matrix can be readily used for device design and simulation purposes.
Magnetism without magnetic impurities in ZrO2 oxide
Authors: Máca František , Kudrnovský Josef , Drchal Václav , Bouzerar Georges
Published: May 2008

We present an ab initio study of the magnetism induced in ZrO2 dioxide by substitution of the cation by an impurity from the groups 1A or 2A of the Periodic Table (K and Ca). It is demonstrated that the K impurity leads to a robust induced magnetic moment on the surrounding O atoms in the cubic ZrO2 host whilst Ca impurity leads to a nonmagnetic groundstate. The estimated Curie temperature is above room temperature.
Effect of Sn grain orientation on electromigration degradation mechanism in high Sn-based Pb-free solders
Authors: Lu Minhua , Shih Da-Yuan , Lauro Paul , Goldsmith Charles , Henderson Donald W.
Published: May 2008

Electromigration induced damage strongly depends on Sn-grain orientation in Pb-free solders. Rapid depletion of intermetallic compounds and under bump metallurgy led to significant damages caused by the fast diffusion of Cu and Ni along the c axis of Sn crystals. When the c axis of Sn grain is not aligned with the current direction, electromigration (EM) damage is dominated by Sn self-diffusion, which takes longer to occur. This is a direct proof of the highly anisotropic diffusion behavior in Sn. Due to the presence of twin structures and stable Ag3Sn network, SnAg(Cu) solders are less susceptible to grain orientation effects and showed better EM performance than SnCu solders.
Tungsten black absorber for solar light with wide angular operation range
Authors: Rephaeli Eden , Fan Shanhui
Published: May 2008

Using three-dimensional finite-difference time-domain simulations, we designed a structured tungsten slab with subwavelength periodicity that displays near-complete absorptivity throughout the entire solar spectrum over a wide angular range. The structure consists of a square lattice array of pyramids. The parameters of the pyramids are chosen to provide the optimal impedance matching between free space and tungsten, while the period is chosen to be subwavelength in order to generate absorption over an ultrabroad band of wavelengths.
Intersubband resonant enhancement of the nonlinear optical properties in compositionally asymmetric and interdiffused quantum wells
Authors: Karabulut İbrahim , Şafak Haluk , Tomak Mehmet
Published: May 2008

We report the resonant enhancement of the second- and third-order optical nonlinearities in compositionally asymmetric quantum wells with finite confining potential and interdiffused quantum wells. The energy levels and the envelope wave functions in quantum wells are obtained by solving numerically the Schrödinger equation. The optical rectification, second and third harmonic generation coefficients are calculated within the framework of the density matrix formalism. The effect of the structure parameters such as the well width and the barrier height on the nonlinear optical properties is investigated in detail. The resulting nonlinear susceptibilities obtained in both quantum wells are considerably larger than those of bulk GaAs.
A semiempirical model for two-level system noise in superconducting microresonators
Authors: Gao Jiansong , Daal Miguel , Martinis John M. , Vayonakis Anastasios , Zmuidzinas Jonas , Sadoulet Bernard , Mazin Benjamin A. , Day Peter K. , Leduc Henry G.
Published: May 2008

We present measurements of the low-temperature excess frequency noise of four niobium superconducting coplanar waveguide microresonators, with center strip widths sr ranging from 3to20μm. For a fixed internal power, we find that the frequency noise decreases rapidly with increasing center strip width, scaling as 1∕sr1.6. We show that this geometrical scaling is readily explained by a simple semiempirical model which assumes a surface distribution of independent two-level system fluctuators. These results allow the resonator geometry to be optimized for minimum noise.