bluuebunny/crossref_metadata_2025 huggingface dataset:
Interactive instabilities of thin‐walled laminated composite pultrusion box columns
Authors: Kabir Mohammed Zaman , Shafei Erfan
Published: December 2010

The problem of interactive buckling and post‐buckling of intermediate length thin‐walled columns built of laminated plate elements subjected to compressive load has been proposed and solved analytically. Pultrusion columns have wide‐range applications in high‐rise building due to their low weight and high load carrying capacity. Classic stability theory and laminate theory were implemented to prove the existence of mixed‐mode buckling in thin‐walled pultrusion columns. Interactive stability modes can result in lower loading capacity of most compressive members and affects their post‐buckling behaviour in major proportions. Interactive buckling load analysis has been performed by means of a simplified theoretical model and verified by means of numerical analysis. The calculations were carried out for commonly used square section thin‐walled composite columns dimensions. The post‐buckling performance of selected sections has been investigated and an optimum layup configuration criterion for each section has been extracted according to pre‐ and post‐critical behaviour. Copyright © 2010 John Wiley & Sons, Ltd.
Adolescents' Declining Motivation to Learn Science: Inevitable or Not?
Authors: Vedder‐Weiss Dana , Fortus David
Published: December 2010

There is a growing awareness that science education should center not just on knowledge acquisition but developing the foundation for lifelong learning. However, for intentional learning of science to occur in school, out of school, and after school, there needs to be a motivation to learn science. Prior research had shown that students' motivation to learn science tends to decrease during adolescence [Anderman and Young [1994] Journal of Research in Science Teaching 31: 811–831; Lee and Anderson [1993] American Educational Research Journal 30: 585–610; Simpson and Oliver [1990] Science Education 74: 1–18]. This study compared 5th through 8th grade students' self‐reported goal orientations, engagement in science class, continuing motivation for science learning, and perceptions of their schools' and parents' goals emphases, in Israeli traditional and democratic schools. The results show that the aforementioned decline in adolescents' motivation for science learning in school and out of school is not an inevitable developmental trend, since it is apparent only in traditional schools but not in democratic ones. The results suggest that the non‐declining motivation of adolescents in democratic schools is not a result of home influence but rather is related to the school culture. © 2010 Wiley Periodicals, Inc., J Res Sci Teach 48: 199–216, 2011
Examining the effect of teachers' adaptations of a middle school science inquiry‐oriented curriculum unit on student learning
Authors: Fogleman Jay , McNeill Katherine L. , Krajcik Joseph
Published: December 2010

Reform based curriculum offer a promising avenue to support greater student achievement in science. Yet teachers frequently adapt innovative curriculum when they use them in their own classrooms. In this study, we examine how 19 teachers adapted an inquiry‐oriented middle school science curriculum. Specifically, we investigate how teachers' curricular adaptations (amount of time, level of completion, and activity structures), teacher self‐efficacy (teacher comfort and student understanding), and teacher experience enacting the unit influenced student learning. Data sources included curriculum surveys, videotape observations of focal teachers, and pre‐ and post‐tests from 1,234 students. Our analyses using hierarchical linear modeling found that 38% of the variance in student gain scores occurred between teachers. Two variables significantly predicted student learning: teacher experience and activity structure. Teachers who had previously taught the inquiry‐oriented curriculum had greater student gains. For activity structure, students who completed investigations themselves had greater learning gains compared to students in classrooms who observed their teacher completing the investigations as demonstrations. These findings suggest that it can take time for teachers to effectively use innovative science curriculum. Furthermore, this study provides evidence for the importance of having students actively engaging in inquiry investigations to develop understandings of key science concepts. © 2010 Wiley Periodicals, Inc., J Res Sci Teach 48: 149–169, 2011
NICE and general practice: an important partnership in an increasingly complex world
Authors: Littlejohns Peter , Choudhury Moni , Sharma Tarang
Published: December 2010

Recent developments mean that NICE will be increasingly relevant for GPs in the future and bring opportunities to participate in the development of NICE guidance. Copyright © 2010 Wiley Interface Ltd
The case of the boiled bladder – or, how to avoid medical errors
Authors: Kirby Roger , Dasgupta Prokar , Beacock Christopher
Published: December 2010

Not too long ago, a disturbing case occurred in which a thermal injury was sustained by a patient as a result of the use of overheated irrigating fluid during a bladder tumour resection. Sadly, there was not a happy ending. The bladder never recovered from the trauma, but became shrunken and contracted, producing debilitating symptoms. A cystectomy and urinary diversion became necessary, but further complications set in, and eventually these were fatal. To the surprise of all concerned, litigation was not initiated by the family, although the hospital involved did offer a profound apology. So what lessons are there to be learned from so tragic an episode? Copyright © 2010 Wiley Interface Ltd
NLOOK: a computational attention model for robot vision
Authors: Heinen Milton Roberto , Engel Paulo Martins
Published: December 2010

The computational models of visual attention, originally proposed as cognitive models of human attention, nowadays are being used as front-ends to some robotic vision systems, like automatic object recognition and landmark detection. However, these kinds of applications have different requirements from those originally proposed. More specifically, a robotic vision system must be relatively insensitive to 2D similarity transforms of the image, as in-plane translations, rotations, reflections and scales, and it should also select fixation points in scale as well as position. In this paper a new visual attention model, called NLOOK, is proposed. This model is validated through several experiments, which show that it is less sensitive to 2D similarity transforms than other two well known and publicly available visual attention models: NVT and SAFE. Besides, NLOOK can select more accurate fixations than other attention models, and it can select the scales of fixations, too. Thus, the proposed model is a good tool to be used in robot vision systems.
Influences of the genetic neighborhood on ramet reproductive success in a clonal desert cactus
Authors: Carrillo‐Angeles Israel G. , Mandujano María C. , Golubov Jordan
Published: December 2010

Clonal structure in clonal plants can affect sexual reproduction. Individual ramets can decrease reproduction if their neighbors are ramets of the same genet due to inbreeding depression or self‐incompatibility. We assessed ramet reproductive success in the partial self‐incompatible Ferocactus robustus (Cactaceae) as a function of floral display size in focal ramets and floral display size and clonal structure of their reproductive neighborhoods. Ramets were labeled, sized in number of stems, mapped and genetically identified through RAPD markers in one population. A pollen dispersal area of 15‐m radius was established for each ramet to determine the clonal diversity in the neighborhoods. Flower production and fruit set were counted on a monthly basis during one reproductive season as a surrogate of ramet fitness. We expected a decrease in individual ramet reproductive success as a function of the number of reproductive ramets of the same genet in the neighborhood. A total of 272 sampled ramets revealed 116 multilocus genotypes, showing high clonal diversity in the population (G/N = 0.43, D = 0.98). Clonal diversity of neighborhoods ranged from 0.06 to 1 and fruit set varied from 0 to 76.9%. Individual ramet reproductive success was influenced by (1) mate availability, (2) floral display size of a genet within the reproductive neighborhood, and (3) the proportion of distinguishable genotypes. Floral display size of genets and ramets coupled with the genetic diversity within the reproductive neighborhood determines the low sexual reproduction in F. robustus.
Comments on “Black Americans in the 21st Century: Should We be Optimistic or Concerned?”
Authors: Andrews Rodney J.
Published: December 2010

In “Black Americans in the 21st Century: Should we be Optimistic or Concerned?”, Dr. Angel Harris discusses a number of facts about the myriad gaps in performance between black Americans and white Americans. In what follows, I present evidence that suggests that a combination of race-conscious policies and early-childhood investments should be included in any policy that seeks to reduce the gaps in performance between black Americans and white Americans.
Intraoperative Patient Skin Prep Agents: Is There a Difference?
Authors: Zinn Jennifer , Jenkins Jeanne B. , Swofford Vangela , Harrelson Beverly , McCarter Sharon
Published: December 2010

For health care institutions, intraoperative prep agents are a critical link in combating surgical site infections and the associated economic burden. The question remains, is there an intraoperative prep agent that is truly superior to the others? We conducted a literature review to examine available empirical evidence related to intraoperative prep agents used in our health system for open abdominal, general surgery procedures: povidone‐iodine, chlorhexidine gluconate, parachoroxylenol, and iodine povacrylex in 74% isopropyl alcohol. Intraoperative surgical skin prep studies were limited in providing empirical evidence to support one superior prep agent. Each prep agent has a specific mechanism of action along with specific advantages and disadvantages. We concluded that no one perioperative skin prep agent is superior in all clinical situations. Factors to consider when choosing an appropriate intraoperative skin prep agent include contraindications, environmental risks, the patient's allergies and skin condition, the surgical site, the manufacturer recommendations for the prep agent, and surgeon preference.
When the center can hold: The primacy of politics in shaping Russian democracy
Authors: Anderson Richard D.
Published: December 2010

Violations of rights, a weak Duma, political parties dominated by bureaucrats, and corrupt privatization are ordinarily taken as signs or even causes of the failure of democracy in Russia or at best as normal traits of electoral politics in a middle-income state. Yet all of these are natural consequences of introducing democracy in a country with the Russian electorate’s distinctive recent experience of a loss of a third of the state’s territory and half its population. In such a democracy only a centrist, not a liberal, strategy can block a return to authoritarianism, and such a strategy in Russia will subordinate rights to the task of privatization that a Duma weakened by ideological, demographic and geographic impediments to party development cannot conduct. Consequently what are taken as signs or causes of democratic failure in Russia are instead necessary effects of introducing democracy in Russia’s special circumstances.
Particle motion driven by solute gradients with application to autonomous motion: continuum and colloidal perspectives
Authors: BRADY JOHN F.
Published: December 2010

Diffusiophoresis, the motion of a particle in response to an externally imposed concentration gradient of a solute species, is analysed from both the traditional coarse-grained macroscopic (i.e. continuum) perspective and from a fine-grained micromechanical level in which the particle and the solute are treated on the same footing as Brownian particles dispersed in a solvent. It is shown that although the two approaches agree when the solute is much smaller in size than the phoretic particle and is present at very dilute concentrations, the micromechanical colloidal perspective relaxes these restrictions and applies to any size ratio and any concentration of solute. The different descriptions also provide different mechanical analyses of phoretic motion. At the continuum level the macroscopic hydrodynamic stress and interactive force with the solute sum to give zero total force, a condition for phoretic motion. At the colloidal level, the particle's motion is shown to have two contributions: (i) a ‘back-flow’ contribution composed of the motion of the particle due to the solute chemical potential gradient force acting on it and a compensating fluid motion driven by the long-range hydrodynamic velocity disturbance caused by the chemical potential gradient force acting on all the solute particles and (ii) an indirect contribution arising from the mutual interparticle and Brownian forces on the solute and phoretic particle, that contribution being non-zero because the distribution of solute about the phoretic particle is driven out of equilibrium by the chemical potential gradient of the solute. At the colloidal level the forces acting on the phoretic particle – both the statistical or ‘thermodynamic’ chemical potential gradient and Brownian forces and the interparticle force – are balanced by the Stokes drag of the solvent to give the net phoretic velocity.

For a particle undergoing self-phoresis or autonomous motion, as can result from chemical reactions occurring asymmetrically on a particle surface, e.g. catalytic nanomotors, there is no imposed chemical potential gradient and the back-flow contribution is absent. Only the indirect Brownian and interparticle forces contribution is responsible for the motion. The velocity of the particle resulting from this contribution can be written in terms of a mobility times the integral of the local ‘solute pressure’ – the solute concentration times the thermal energy – over the surface of contact between the particle and the solute. This was the approach taken by Córdova-Figueroa & Brady (Phys. Rev. Lett., vol. 100, 2008, 158303) in their analysis of self-propulsion. It is shown that full hydrodynamic interactions can be incorporated into their analysis by a simple scale factor.
Pavel Rozhkov and Slava. ‘The first Soviet whalers in the Antarctic’
Authors: Bulkeley Rip
Published: December 2010

Pavel Sergeyevich Rozhkov was captain of the whale catcher Slava 3 on the first Soviet whaling cruise in the Antarctic, which took place in 1946–1947. He wrote an exceptionally frank and detailed account of the cruise, for those times, which was published in a Lithuanian newspaper and is now presented here for the first time in English translation.
A lost translation of Bellingshausen?
Authors: Bulkeley Rip
Published: December 2010

Frank Debenham believed, on naval authority, that the first English translation of Bellingshausen's account of his 1819–1821 voyage was made during World War I (Debenham 1945: vii). He may have been misinformed.
Abuse is in the eyes of the beholder: using multiple perspectives to evaluate elder mistreatment under round-the-clock foreign home carers in Israel
Authors: AYALON LIAT
Published: December 2010

The overall goal of the study reported in this paper was to examine differences in the perceived occurrence of abuse and neglect as between older care recipients, their family carers, and foreign home-care workers in Israel. Overall, 148 matched family members and foreign home-care workers and 75 care recipients completed a survey of abuse and neglect. Significant discrepancies in their reports of neglect were found, with the foreign home-care workers more likely to identify neglect (66%) than the older adults (27.7%) or their family members (29.5%). Although the rates of reported abuse ranged between 16.4 and 20.7 per cent and the differences were not statistically significant, the different parties assigned the responsibility for the abuse to different perpetrators. The independent variables that significantly associated with abuse and neglect also varied by the three groups of participants. The findings suggest that even with round-the-clock home care, the basic needs of many older adults are not met, and that many experience substantial abuse. The study emphasises the subjective nature of abuse and neglect, and suggests that more education about what constitutes elder abuse and neglect may lead to more accurate and consistent reports across reporting sources. Incorporating data from the various stakeholders may enhance the early identification of elder abuse and neglect.
Cognitive development of bilingual children
Authors: Barac Raluca , Bialystok Ellen
Published: December 2010

There has always been a common-sense view that the number of languages that children learn, whether through natural exposure or educational intervention, has consequences for their development. The assumption was that these consequences were potentially damaging. Even now, after approximately 50 years of research on the topic, parents remain concerned about their children's development when it includes a bilingual experience. It is now clear that although parents were correct that speaking more than one language has consequences, the assumption about the nature of these consequences is not: the outcome of the experience is in fact the opposite of what many early researchers claimed and what many contemporary parents intuitively believe. In contrast to early warnings about negative consequences, bilingualism turns out to be an experience that benefits many aspects of children's development. Although there are documented delays in acquiring some formal aspects of each language, such as vocabulary (Bialystok 2010), bilingualism has either no effect (intelligence) or positive effects (metalinguistic awareness, cognitive development) on development.
Second Language Research Forum Colloquia 2009
Authors: Loewen Shawn
Published: December 2010

Presented at the Second Language Research Forum, Michigan State University, USA; 31 October 2009

Focus on form, i.e. brief attention to language items within a larger meaning-focused context (Long 1991; Ellis 2001), occurs in a variety of L2 instructional contexts. Meta-analyses of the effectiveness of focus on form have found overall positive effects; however, these meta-analyses have commented on the small number of studies available for synthetic analyses, particularly when considering the effects of specific characteristics of focus on form (e.g. Norris & Ortega 2001; Russell & Spada 2006; Mackey & Goo 2007). Consequently, this colloquium continued the investigation of specific focus on form variables to further our understanding of why ‘sometimes focus on form works, and sometimes it does not’ (Williams 2005: 685).
Identifying appropriate sampling and modelling approaches for analysing distributional patterns of Antarctic terrestrial arthropods along the Victoria Land latitudinal gradient
Authors: Caruso Tancredi , Hogg Ian D. , Bargagli Roberto
Published: December 2010

Biotic communities in Antarctic terrestrial ecosystems are relatively simple and often lack higher trophic levels (e.g. predators); thus, it is often assumed that species’ distributions are mainly affected by abiotic factors such as climatic conditions, which change with increasing latitude, altitude and/or distance from the coast. However, it is becoming increasingly apparent that factors other than geographical gradients affect the distribution of organisms with low dispersal capability such as the terrestrial arthropods. In Victoria Land (East Antarctica) the distribution of springtail (Collembola) and mite (Acari) species vary at scales that range from a few square centimetres to regional and continental. Different species show different scales of variation that relate to factors such as local geological and glaciological history, and biotic interactions, but only weakly with latitudinal/altitudinal gradients. Here, we review the relevant literature and outline more appropriate sampling designs as well as suitable modelling techniques (e.g. linear mixed models and eigenvector mapping), that will more adequately address and identify the range of factors responsible for the distribution of terrestrial arthropods in Antarctica.
The biogeochemistry of meltwater habitats in the Darwin Glacier region (80°S), Victoria Land, Antarctica
Authors: Webster-Brown J. , Gall M. , Gibson J. , Wood S. , Hawes I.
Published: December 2010

Meltwater habitats in the Darwin Glacier region, Victoria Land (80°S), were sampled in December 2007 and January 2009 to characterize their microbial and metazoan ecology, nutrient status and geochemistry. Targeted areas included terrestrial ponds of the Grant Valley, Lake Wellman, Tentacle Ridge and Diamond Hill, and supraglacial ponds and cryoconite holes of the lower Darwin Glacier. Geochemistry ranged from Na-Cl dominated terrestrial ponds to Na-HCO3dominated, dilute supraglacial ponds and cryoconites. All showed the nitrate enrichment typical of inland ponds of Victoria Land (up to 13 g.l-1NO3-N), with some precipitating nitratine (NaNO3) salt. Elevated pH indicated ongoing photosynthetic processes. Benthic microbial mats were thin and poorly developed, dominated by oscillatoriacean cyanobacteria. Nitrogen-fixing genera were generally absent and diatoms were rare. A large (20 μm long)Cyanothecespecies was the most abundant cyanobacterium in the water and in sediments of the cryoconites. DNA finger-printing identified distinct differences in cyanobacterial and bacterial community structure between the cryoconites, terrestrial ponds and ponds on glacial margins. Eleven metazoan species were identified, with rotifers being the most abundant. Pond substrate (terrestrial rock, ice-cored moraine or supraglacial ice) proved to be a more significant influence on biogeochemistry than other aspects of geography or climatic conditions.
Large-time rescaling behaviours of Stokes and Hele-Shaw flows driven by injection
Authors: LIN Y. L.
Published: December 2010

In this paper, we give a precise description of the rescaling behaviours of global strong polynomial solutions to the reformulation of zero surface tension Hele-Shaw problem driven by injection, the Polubarinova-Galin equation, in terms of Richardson complex moments. From past results, we know that this set of solutions is large. This method can also be applied to zero surface tension Stokes flow driven by injection and a rescaling behaviour is given in terms of many conserved quantities as well.
Working memory influences on cross-language activation during bilingual lexical disambiguation
Authors: ARÊAS DA LUZ FONTES ANA B. , SCHWARTZ ANA I.
Published: December 2010

This study investigated the role of verbal working memory on bilingual lexical disambiguation. Spanish–English bilinguals read sentences that ended in either a cognate or noncognate homonym or a control word. Participants decided whether follow-up target words were related in meaning to the sentences. On critical trials, sentences biased the subordinate meaning of a homonym and were followed by targets related to the dominant meaning. Bilinguals with high span were faster at rejecting unrelated targets when the sentences ended in a homonym, whereas bilinguals with low span were slower. Furthermore, error rates for bilinguals with low span showed cognate inhibition, while bilinguals with high span showed no effects of cross-language activation. Results demonstrated that bilinguals with high span benefit from shared lexical codes whether these converge on to a single semantic representation (cognates) or not (homonyms). Conversely, bilinguals with low span showed inhibition from the competing lexical codes, even when they converge onto a single semantic representation.
Real-Time Scanning Charged-Particle Microscope Image Composition with Correction of Drift
Authors: Cizmar Petr , Vladár András E. , Postek Michael T.
Published: December 2010

In this article, a new scanning electron microscopy (SEM) image composition technique is described, which can significantly reduce drift related image corruptions. Drift distortion commonly causes blur and distortions in the SEM images. Such corruption ordinarily appears when conventional image-acquisition methods, i.e., “slow scan” and “fast scan,” are applied. The damage is often very significant; it may render images unusable for metrology applications, especially where subnanometer accuracy is required. The described correction technique works with a large number of quickly taken frames, which are properly aligned and then composed into a single image. Such image contains much less noise than the individual frames, while the blur and deformation is minimized. This technique also provides useful information about changes of the sample position in time, which may be applied to investigate the drift properties of the instrument without a need of additional equipment.
Die Bedeutung der Phonemdiskrimination für eine Lese-Rechtschreibstörung in den Klassenstufen eins bis sechs
Authors: Brunner Monika , Bäumer Claudia , Rosenauer Karin , Scheller Holger , Plinkert Peter
Published: December 2010

Fragestellung: Die Forschung zur Phonemdiskriminationsschwäche im Ursachengefüge der Legasthenie wird in der Literatur überwiegend auf die Variable des Lesens bezogen. Ziel der vorliegenden Studie ist es, den Zusammenhang von Lautdiskrimination und Rechtschreibleistung in Abhängigkeit von der Klassenstufe zu erfassen. Methodik: Die Befunde im Heidelberger Lautdifferenzierungstest (HLAD) und die Rechtschreibleistung von 253 Kindern, die zur Abklärung von LRS und/oder auditiver Wahrnehmungsstörung die Phoniatrie/Pädaudiologie aufsuchten, wurden retrospektiv analysiert. Ergebnisse: Die Phonemdiskrimination, die über den HLAD als auditive Vergleichsleistung, als Nachsprech- und als Benennleistung erfasst wurde, zeigte einen hochsignifikanten Zusammenhang zur Rechtschreibleistung in den ersten Klassenstufen. Auch in den höheren Klassenstufen ist die Schwäche in der Phonemdiskrimination noch nachweisbar. Hier ist die Korrelation zur Rechtschreibleistung jedoch geringer, wenngleich noch signifikant. Anhand der Phonemdiskrimination lässt sich die Rechtschreibleistung signifikant unterscheiden. Schlussfolgerungen: Schwächen der Phonemdiskrimination sind ein Indikator für eine mangelnde Sprachverarbeitung. Sie treten bis in höhere Klassenstufen hinein auf, der Einfluss auf die Rechtschreibung ist jedoch in den ersten Klassen am höchsten. Ein logopädisches Training der Phonemdiskriminationsschwäche sollte überwiegend in den ersten Klassenstufen im Mittelpunkt der Therapie stehen. In den höheren Klassenstufen sind sprachanalytische und metasprachliche Kognitionen in den Vordergrund zu rücken.
Das neue Entgeltsystem
Authors: Kölch Michael , Fegert Jörg M. , Bleich Sabrina , Schepker Renate
Published: December 2010

Das Krankenhausfinanzierungsgesetz sieht in § 17d die Einführung eines pauschalierenden Entgeltsystems für die psychiatrischen und psychosomatischen Kliniken bis 2013 vor. In verschiedenen Stufen sollen Kennwerte erhoben, Leistungen dokumentiert und das bisherige System tagesgleicher Entgelte abgelöst werden. Der Beitrag soll eine Übersicht über die gesetzlichen Rahmenbedingungen, die wichtigen Veränderungen durch das neue System geben und die möglichen Chancen, aber auch die Risiken dieses Systems aufzeigen. Insgesamt ist heute schon abzusehen, dass zwar ein großer Aufwand an Dokumentation und Transparenz der psychiatrischen Arbeit durch das System entstehen wird, eine unmittelbare Verbesserung aber für die Arbeit am Patienten und die Patienten sich vermutlich kaum ergeben wird, wenn nicht der Schritt zur Einführung von moderneren Behandlungskonzepten gegangen wird, der im Gesetz ebenfalls angelegt ist.
Improving Risk Assessment with Suicidal Patients
Authors: Nelson Charles , Johnston Megan , Shrivastava Amresh
Published: December 2010

Background: Although a number of suicide-risk assessment tools are available to clinicians, the high levels of suicide still evident in society suggest a clear need for new strategies in order to facilitate the prevention of suicidal behaviors. Aims: The present study examined the utilization of a new structured clinical interview called the Scale for Impact of Suicidality Management, Assessment, and Planning of Care (SIS-MAP). Methods: SIS-MAP ratings were obtained from a group of incoming psychiatric patients over a 6-month period at Regional Mental Health Care, St. Thomas, Canada. Results: A canonical discriminant function analysis resulted in a total 74.0% of original grouped cases correctly classified based on admission status (admitted or not; Wilks λ = .749, p < .001). The specificity of the scale was 78.1%, while the sensitivity of the scale was 66.7%. Additionally, mean total scores on the scale were used to establish clinical cutoffs to facilitate future level of care decisions. Conclusions: Preliminary analysis suggests the SIS-MAP is a valid and reliable tool for determining the level of psychiatric care needed for adults with suicidal ideation.
Temperature variability in a shallow, tidally isolated coral reef lagoon
Authors: McCabe R. M. , Estrade P. , Middleton J. H. , Melville W. K. , Roughan M. , Lenain L.
Published: December 2010

Temperature data collected in the shallow, tidally isolated reef flat/lagoon of Lady Elliot Island off Queensland, Australia, show marked variability under solar and tidal forcing. Sea level drops below the height of the protective lagoon rim for a few hours during low tide, effectively isolating the remaining water. Because the lagoon is shallow, its temperature change (from diurnal solar forcing and cooling) is amplified. We develop a simple analytical model to predict the time evolution of mean lagoon temperature, beginning with a well‐mixed control volume. This approach highlights the asymmetric flood/ebb physics of tidally isolated lagoons. After discussing the response of this model, we compare it with results from two idealized numerical simulations that illustrate differing aspects of lagoon temperature variability under “potential flow” and “prevailing current” situations. The conceptual model captures the essence of lagoon temperature variability and underscores the importance of solar‐lunar phasing. However, because of the well‐mixed assumption, it cannot reproduce sudden temperature transitions associated with new incoming water masses. Observations show that a slowly progressing thermal wave inundates the lagoon on rising tides. This wave is similar to our “potential flow” simulation in that it is approximately radially symmetric. On the other hand, it appears to advectively replace resident lagoon water, similar to our “prevailing current” simulations. We attempt to account for this behavior with a simple “frontal” modification to our conceptual model. Results show that this frontal model is able to capture the sudden temperature transitions present in the data and offers improved predictive capabilities over the well‐mixed model.
Overnight atmospheric transport and chemical processing of photochemically aged Houston urban and petrochemical industrial plume
Authors: Zaveri Rahul A. , Voss Paul B. , Berkowitz Carl M. , Fortner Edward , Zheng Jun , Zhang Renyi , Valente Ralph J. , Tanner Roger L. , Holcomb Daniel , Hartley Thomas P. , Baran Leslie
Published: December 2010

Overnight atmospheric transport and chemical evolution of photochemically aged Houston urban and petrochemical industrial plume were investigated in July 2005. We report here on the 26 July episode in which the aged plume was tagged 1.5 h before sunset with a pair of free‐floating controlled meteorological balloons, which guided quasi‐Lagrangian aircraft sampling in the plume as it was advected 300 km to the north over 8 h. The aged plume around sunset was well mixed within a 1600 m residual layer, and was characterized by enhanced levels of aerosol, O3, CO, olefins, acetaldehyde, total odd nitrogen compounds (NOy), and relatively small amounts (<1 ppbv) of NOx. The plume experienced appreciable shearing overnight due to the development of a low‐altitude nocturnal jet between 300 and 500 m above mean sea level (MSL). However, the plume above 600 m MSL remained largely undiluted even after 8 h of transport due to lack of turbulent mixing above the jet. About 40–60% of the NOx present in the aged plume around sunset was found to be depleted over this 8 h period. A constrained plume modeling analysis of the quasi‐Lagrangian aircraft observations suggested that by dawn this NOx was converted to nitric acid, organic nitrates, and peroxy acyl nitrates via reactions of NO3 radicals with enhanced levels of olefins and aldehydes in the plume. Sensitivity of NOx depletion to heterogeneous hydrolysis of N2O5 on aerosols was examined. These results have significant implications for the impacts of urban and industrial pollution on far downwind regions.
Phosphorus export from a restored wetland ecosystem in response to natural and experimental hydrologic fluctuations
Authors: Ardón Marcelo , Montanari Shaena , Morse Jennifer L. , Doyle Martin W. , Bernhardt Emily S.
Published: December 2010

Wetland restoration is a commonly used approach to reduce nutrient loading to freshwater and coastal ecosystems, with many wetland restoration efforts occurring in former agricultural fields. Restored wetlands are expected to be effective at retaining or removing both nitrogen and phosphorus (P), yet restoring wetland hydrology to former agricultural fields can lead to the release of legacy fertilizer P. Here, we examined P cycling and export following rewetting of the Timberlake Restoration Project, a 440 ha restored riverine wetland complex in the coastal plain of North Carolina. We also compared P cycling within the restored wetland to two minimally disturbed nearby wetlands and an adjacent active agricultural field. In the restored wetland we observed increased soluble reactive phosphorus (SRP) concentrations following initial flooding, consistent with our expectations that P bound to iron would be released under reducing conditions. SRP concentrations in spring were 2.5 times higher leaving the restored wetland than a forested wetland and an agricultural field. During two large‐scale drawdown and rewetting experiments we decreased the water depth by 1 m in ∼10 ha of inundated wetland for 2 weeks, followed by reflooding. Rewetting following experimental drainage had no effect on SRP concentrations in winter, but SRP concentrations did increase when the experiment was repeated during summer. Our best estimates suggest that this restored wetland could release legacy fertilizer P for up to a decade following hydrologic restoration. The time lag between restoration and biogeochemical recovery should be incorporated into management strategies of restored wetlands.
Valuing water resources in developing countries: A semiparametric approach to valuation models
Authors: Belluzzo Walter
Published: December 2010

Valuation of projects for the preservation of water resources provides important information to policy makers and funding institutions. Standard contingent valuation models rely on distributional assumptions to provide welfare measures. Deviations from assumed and actual distribution of benefits are important when designing policies in developing countries, where inequality is a concern. This article applies semiparametric methods to obtain estimates of the benefit from a project for the preservation of an important Brazilian river basin. These estimates lead to significant differences from those obtained using the standard parametric approach.
On the heating of the outer radiation belt to produce high fluxes of relativistic electrons: Measured heating rates at geosynchronous orbit for high‐speed stream‐driven storms
Authors: Borovsky Joseph E. , Denton Michael H.
Published: December 2010

The heating rate of the outer electron radiation belt at geosynchronous orbit is determined for the interval from 36 to 72 h after the onset of high‐speed stream‐driven storms. Multisatellite measurements of the radiation belt temperature are used for 93 high‐speed stream‐driven storms. During the storms, the outer electron radiation belt temperature changes from ∼120 keV to ∼190 keV. The average heating rate of 32 keV d−1is obtained. The heating rate during the storms is found to be positively correlated with the solar wind velocity and with the Kp index of geomagnetic activity and to be negatively correlated with the solar wind number density. When the solar wind velocity is held fixed, the correlation of the heating rate with Kp vanishes. Expressions for the change in the heating rate as function of the solar wind speed, the solar wind density, and the Kp index are fit to the data. The heating rate is uncorrelated with the amplitude of magnetic field fluctuations in the magnetosphere. Correlations between the heating rate and the level of velocity, density, and magnetic field fluctuations in the magnetosphere and in the solar wind are weaker than the correlations of the heating rate with the solar wind velocity and density. The heating rates correspond to a kinetic energy density change of 3.6 × 10−11erg cm−3d−1at geosynchronous orbit, to a specific entropy change of 4.1 × 106eV cm2d−1at geosynchronous orbit, and to a total heating rate of the geosynchronous orbit region of 5.3 × 106Watts.
Excitation of electron cyclotron harmonic waves in the inner Saturn magnetosphere within local plasma injections
Authors: Tao X. , Thorne R. M. , Horne R. B. , Grimald S. , Arridge C. S. , Hospodarsky G. B. , Gurnett D. A. , Coates A. J. , Crary F. J.
Published: December 2010

Strong electron cyclotron harmonic (ECH) waves have been observed by Cassini associated with local plasma injection regions in the Saturnian magnetosphere. Using measured electron distributions from the Cassini plasma spectrometer, we calculated local growth rates and path‐integrated wave gain of ECH waves inside an injection event using the HOTRAY code. We showed that electrons with energy near a few eV have a collision frequency comparable to their bounce frequency; thus, they cannot have an empty loss cone. We then demonstrated that the growth of ECH waves inside the injection event can be driven by electron phase space density gradients associated with the loss cone distribution of injected electrons at energies between a few hundred eV and a few keV. This conclusion is contrary to previous results that the source of free energy for growth of ECH waves is provided by electrons near a few eV. Results in this work are helpful for understanding the generation of ECH waves and their roles in electron dynamics in the Saturnian magnetosphere.
Modeling the contributions of ring, tail, and magnetopause currents to the corrected Dst index
Authors: Asikainen T. , Maliniemi V. , Mursula K.
Published: December 2010

We present a new semiempirical model describing the contributions of the ring, tail, and magnetopause currents to the Dcx index. We use the isotropic boundary (IB) location of energetic particles measured by the NOAA/POES satellites, as a proxy for the tail current strength. Using local linear regression, we derive the model parameters and their functional dependencies on solar wind and interplanetary magnetic field parameters and on IB latitude. The model gives the ring, tail, and magnetopause current contributions for the whole time interval 1999–2007, performing roughly equally well during all activity levels. We find that the coefficient of proportionality between the square root of solar wind pressure and the magnetopause current contribution is larger than in earlier estimates. Ring current decay time is found to decrease with increasing solar wind electric field and dynamic pressure. We estimate the average quiet time level of the combined ring and tail (magnetopause) current contributions to Dcx to be roughly −7 nT (+13 nT). The average tail current contribution is found to be about 34% of the Dcx index, which is somewhat larger than previous estimates based on smaller‐intensity storms. For individual storms the tail current contribution can reach up to −160 nT (about 40%–60% of the pressure corrected Dcx). The present model agrees well with earlier results for individual storms based on detailed dynamical models of the magnetosphere. Our work demonstrates that the different current contributions to Dcx during both active and quiet time intervals can be reliably estimated using solar wind observations and isotropic boundary location.
New methods for estimating the spatial distribution of locked asperities and stress‐driven interseismic creep on faults with application to the San Francisco Bay Area, California
Authors: Johnson Kaj M. , Fukuda Jun'ichi
Published: December 2010

We introduce new forward and inverse methods for inferring long‐term fault slip rates, interseismic fault creep rates, and distribution of locked and creeping patches on faults using geodetic and geologic data. The forward model consists of fault‐bounded blocks in an elastic crust overlying a Maxwell viscoelastic mantle. Interseismic elastic distortion of the blocks is modeled due to periodic locking and unlocking of faults throughout the earthquake cycle. Patches on the fault are assumed to be either locked during the interseismic period or creeping at constant shear stress. We utilize a Bayesian, probabilistic inversion method to infer the posterior probability distribution of long‐term interseismic fault slip rates, distribution of locked and creeping patches, and relative weighting of multiple data sets. We illustrate the method with an inversion of a synthetic data set. We apply the method to estimate fault slip rates and the distribution of interseismic creep on faults in the San Francisco Bay Area, CA, using GPS‐derived velocities and geologic measurements of fault slip rates. We show that the inferred fault slip rates and areas of the locked regions of faults are sensitive to the assumed viscosity of the upper mantle and the timing of past earthquakes and can be significantly different from values inferred from elastic models that do not include viscous flow. Considering models with different viscosities, inferred fault slip rates on major Bay Area faults can differ by factors of 1.5–4.0 and the inferred moment accumulation rate can differ by factors of 2–13.
General circulation of Lake Superior: Mean, variability, and trends from 1979 to 2006
Authors: Bennington Val , McKinley Galen A. , Kimura Nobuaki , Wu Chin H.
Published: December 2010

Previous observations and modeling studies of Lake Superior have only partly elucidated its large‐scale circulation, in terms of both the climatological state and interannual variability. We use an eddy resolving, three‐dimensional hydrodynamic model to bridge this gap. We simulate Lake Superior circulation and thermal structure from 1979 to 2006 and consider the mechanisms responsible for the flow. Model results are compared to available direct observations of temperature and currents. Circulation in the lake is primarily cyclonic during all seasons, and a two‐gyre structure is sometimes present. Surface circulation patterns in winter mimic wind directions but become organized in summer by the presence of thermal gradients. On the annual mean, nearshore currents are controlled by thermal gradients, while offshore flow is primarily determined by the wind. From a uniform bathymetry simulation, we determine that topographic variations cause small‐scale structures in the open lake flow and are critical to the development of nearshore‐offshore temperature gradients. The lake exhibits significant variability in current speed and direction on synoptic time scales, but coherent patterns of interannual variability are not found. Long‐term trends due to changing meteorological forcing are found. Model results suggest the increase in lake surface temperature (0.37°C/decade) is significantly correlated to increases in wind speed above the lake (0.18 m/s/decade), increased current speeds (0.37 cm/s/decade), and declining ice coverage (−886 km2/yr).
Coupling of the microphysical and optical properties of an Arctic nimbostratus cloud during the ASTAR 2004 experiment: Implications for light‐scattering modeling
Authors: Jourdan Olivier , Mioche Guillaume , Garrett Timothy J. , Schwarzenböck Alfons , Vidot Jérôme , Xie Yu , Shcherbakov Valery , Yang Ping , Gayet Jean‐François
Published: December 2010

Airborne measurements in an Arctic mixed‐phase nimbostratus cloud were conducted in Spitsbergen on 21 May 2004 during the international Arctic Study of Tropospheric Aerosol, Clouds and Radiation (ASTAR) campaign. The in situ instrument suite aboard the Alfred Wegener Institute Polar 2 aircraft included a polar nephelometer (PN), a cloud particle imager (CPI), a Nevzorov probe, and a standard PMS 2DC probe to measure the cloud particle single‐scattering properties (at a wavelength of 0.8 μm), and the particle morphology and size, as well as the in‐cloud partitioning of ice/water content. The main objective of this work is to present a technique based on principal component analysis and light‐scattering modeling to link the microphysical properties of cloud particles to their optical characteristics. The technique is applied to the data collected during the 21 May case study where a wide variety of ice crystal shapes and liquid water fractions were observed at temperatures ranging from −1°C to −12°C. CPI measurements highlight the presence of large supercooled water droplets with diameters close to 500 μm. Although the majority of ice particles were found to have irregular shapes, columns and needles were the prevailing regular habits between −3°C and −6°C while stellars and plates were observed at temperatures below −8°C. The implementation of the principal component analysis of the PN scattering phase function measurements revealed representative optical patterns that were consistent with the particle habit classification derived from the CPI. This indicates that the synergy between the CPI and the PN can be exploited to link the microphysical and shape properties of cloud particles to their single‐scattering characteristics. Using light‐scattering modeling, we have established equivalent microphysical models based on a limited set of free parameters (roughness, mixture of idealized particle habits, and aspect ratio of ice crystals) that reproduce the main optical features assessed for cloud regions with different particle geometries and liquid water fractions. However, the retrieved bulk microphysical parameters can substantially differ from the measurements (by several times for the effective size and up to 3 orders of magnitude for the number concentration). Several possible explanations for these discrepancies are discussed. The retrievals show that the optical contribution of small particles with sizes lower than 50 μm (droplets and ice crystals) is significant, always exceeding 50% of the total scattering signal, and thus needs to be more accurately quantified. The shattering of large ice crystals on the shrouded inlet of the PN could also strongly affect the retrieved microphysical parameters.