bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of culture water hardness on the sensitivity ofCeriodaphnia dubiato copper toxicity
Authors: Naddy Rami B. , Stern Gina R. , Gensemer Robert W.
Published: March 2010

We examined whether the sensitivity of Ceriodaphnia dubia to copper toxicity was influenced by the hardness of the water in which they were reared or in which they were exposed. Organisms cultured in very hard water were 1.5-fold less sensitive to copper than those in moderately hard water. However, the hardness of the exposure water had a greater (2.5-fold) effect on copper median effective concentration (EC50s).
Avian food selection with application to pesticide risk assessment: Are dead and desiccated insects a desirable food source?
Authors: Stafford Jennifer M. , Brewer Larry W. , Gessaman James A.
Published: March 2010

Past evaluations of pesticide exposure have been conducted with substantial uncertainty regarding avian consumption of contaminated food items. One question is whether birds consume invertebrates that are killed by a chemical application and that may present an increasing chemical concentration as they desiccate. We addressed the research question in two phases. First, a laboratory study was conducted in which wild-caught birds were individually offered three food choices, i.e., live, fresh-dead, and desiccated insect larvae. Second, these same food choices plus live, fresh-dead, and desiccated crickets were presented in study plots in two agricultural crops, i.e., a cornfield and an orchard. The experimental food items were monitored with videography equipment to determine their fate and to compare laboratory and field results. Laboratory results showed that birds have a strong preference for live and fresh-dead prey over desiccated prey, with live prey taken before fresh-dead prey in most trials. The field study revealed a similar preference for live prey over desiccated prey, with preference for fresh-dead prey intermediate to the two other types.
In vivo and in vitro assessment of the androgenic potential of a pulp and paper mill effluent
Authors: Ellis Rosanne J. , van den Heuvel Michael R. , Bandelj Emil , Smith Murray A. , McCarthy Lynda H. , Stuthridge Trevor R. , Dietrich Daniel R.
Published: March 2010

The androgenic potential of a New Zealand pulp and paper mill effluent was measured by applying a combination of in vitro and in vivo bioassays with mosquitofish (Gambusia affinis) and goldfish (Carassius auratus). The in vivo method assessed the rate of gonopodial development (masculinization) and alterations from normal reproductive behavior in adult female mosquitofish exposed for 21 d to untreated or secondary-treated pulp mill effluent. A second in vivo mosquitofish exposure tested the effect of glass-fiber (type C) filtration of secondary-treated effluent on rates of expression of the same endpoints. Extractable organics analyses of effluents and extracts thereof were conducted. Mosquitofish demonstrated significant masculinization on exposure to either treated or untreated effluent; the frequency of gonopodial development was reduced with effluent secondary-treatment. Male mating behavior was observed in the masculinized adult females. Glass-fiber (type F) filtration of the treated effluent eliminated the masculinizing effect, suggesting that the bioactive compounds were associated with the suspended solids. The in vitro method measured the binding of compounds within a treated thermomechanical/bleached kraft effluent extract to androgen receptors contained in goldfish testis cytosol. Exposure to extracts of either the particulate (glass-fiber filtered) or the dissolved organic fraction of the effluent produced significant binding (as indicated by the displacement of radiolabeled testosterone) to the androgen receptor in goldfish gonadal tissue. Thus, the dissolved organics extract of the treated effluent contained compounds androgenic to goldfish in vitro but not to mosquitofish in vivo. The combined in vitro and in vivo data suggest that the effluent in question could exert effects on the reproductive physiology of fishes through an androgenic mechanism. The androgenic compounds androstenedione and testosterone were not detected in the extracts used for the in vitro component of this study.
Using marine bioassays to classify the toxicity of dutch harbor sediments
Authors: Stronkhorst Joost , Schipper Cor , Brils Jos , Dubbeldam Marco , Postma Jaap , van de Hoeven Nelly
Published: March 2010

A procedure was developed to assess contaminated marine sediments from Dutch harbors for possible adverse biological effects using three laboratory bioassays: A 10-d survival test with the amphipod Corophium volutator, a 14-d survival test with the heart urchin Echinocardium cordatum (adults), and the bioluminescence inhibition test with the bacterium Vibrio fischeri (Microtoxr̀ solid phase test [SP]). Microtox results were mathematically corrected for the modifying influence of fine sediment particles. After a validation procedure on test performance and modifying factors, respectively, 81%, 99%, and 90% of the amphipod, heart urchin, and Microtox results were approved. Lower and upper threshold limits for biological effects were set at respectively 24 and 30% mortality for C. volutator, 27 and 35% mortality for E. cordatum, and 24 and 48 toxic units for the Microtox SP based on significant differences with control sediment and the performance of reference sediments. The bioassays clearly distinguished harbor sediments that give rise to acute effects and those that do not. Threshold limits for the amphipods, heart urchins, and bacteria were exceeded in, respectively, 9 to 17%, 33 to 40%, and 23 to 50% of the sediment samples. Highest effects were observed in sediments from the northerly harbors; there was significantly less response in sediments from the Delta Region and the port of Rotterdam (The Netherlands). The procedure outlined in this paper can be used for routine screening of contaminated dredged material that is proposed for open water disposal.
Joint acute toxicity of diazinon and copper toCeriodaphnia dubia
Authors: Banks Kenneth E. , Wood Sylvia H. , Matthews Cathy , Thuesen Kevin A.
Published: March 2010

Diazinon and copper are two contaminants that are widely found in urban streams and in municipal wastewater effluents. Because these contaminants may be found concurrently, the potential for their joint toxicity is of interest, particularly with regard to toxicity testing of wastewater effluents and the ecological implications of simultaneous exposures in urban streams. Although interactions between metals are well studied, relatively little is known about interactions between metals and organophosphate compounds such as diazinon. In this study, the interaction between copper and diazinon was evaluated using cladoceran (Ceriodaphnia dubia) in 48-h static tests within laboratory water. Using toxic units derived from concurrently established 48-h median lethal concentration values (LC50) of test organisms of each individual toxicant, the effects of the mixture of copper and diazinon on the survival of C. dubia were shown to be generally nonconcentration additive (LC50 significantly greater than one toxic unit). However, evaluation of the dose-response relationship across the entire range of effect levels revealed that the mortality induced by the mixture of copper and diazinon supported concentration additivity at higher effect levels.
Analysis of field and laboratory data to derive selenium toxicity thresholds for birds
Authors: Adams William J. , Brix Kevin V. , Edwards Melanie , Tear Lucinda M. , Deforest David K. , Fairbrother Anne
Published: March 2010

In this paper, we critically evaluate the statistical approaches and datasets previously used to derive chronic egg selenium thresholds for mallard ducks (laboratory data) and black-necked stilts (field data). These effect concentration thresholds of 3%, 10% (EC10), or 20% have been used by regulatory agencies to set avian protection criteria and site remediation goals, thus the need for careful assessment of the data. The present review indicates that the stilt field dataset used to establish a frequently cited chronic avian egg selenium threshold of 6 mg/kg dry weight lacks statistical robustness (r2 = 0.19-0.28 based on generalized linear models), suggesting that stilt embryo sensitivity to selenium is highly variable or that factors other than selenium are principally responsible for the increase in effects observed at the lower range of this dataset. Hockey stick regressions used with the stilt field dataset improve the statistical relationship (r2 = 0.90-0.97) but result in considerably higher egg selenium thresholds (EC10 = 21-31 mg/kg dry wt). Laboratory-derived (for mallards) and field-derived (for stilts) teratogenicity EC10 values are quite similar (16-24 mg/kg dry wt). Laboratory data regarding mallard egg inviability and duckling mortality data provide the most sensitive and statistically robust chronic threshold (EC10) with logit, probit, and hockey stick regressions fitted to laboratory data, resulting in mean egg selenium EC10 values of 12 to 15 mg/kg dry weight (r2 = 0.75-0.90).
Silver uptake by a marine diatom and its transfer to the coastal copepod Acartia spinicauda
Authors: Xu Yan , Wang Wen-Xiong
Published: March 2010

Silver(Ag) is an important metal contaminant in many coastal waters and often is accompanied by high nutrient concentrations in the effluent outfall. The biological uptake of Ag by the marine diatom Thalassiosira pseudonana at various levels of nitrate, ammonium, and phosphate was examined under different growth conditions of the cells. The biological uptake of Ag increased significantly with increasing concentrations of nitrate, ammonium, and phosphate, presumably because of the increase in algal growth rate or increasing sulfur-containing ligands available for Ag transport. The calculated Ag uptake rate constants increased by 3 to 16 times with increasing nitrate and ammonium concentration from 5.88 μM to 176 μM. The assimilation efficiency (AE) of Ag by the coastal copepod Acartia spinicauda was quantified under different ecological and chemical conditions of the diatom prey. The Ag AEs were in the range of 3 to 23%, and increased with decreasing diatom food concentrations or when the diatoms were grown at a lower nutrient level. Significant correlations were demonstrated between the AE and the distribution of Ag in the diatom's cytoplasm, the Ag concentration factor in the diatoms, Ag retention in the particles during the feeding period, and the Ag gut passage time in the copepods. Desorption within the copepod's gut appears to play a critical role in Ag assimilation and partially accounts for the variability of Ag AEs under different food and geochemical conditions. Our study highlights that several geochemical and physiological processes all significantly affect Ag trophic transfer in marine copepods. Given the dependence of Ag transfer on its concentration in ingested particles and food concentration, dietary uptake of Ag is probably variable in natural environments. The influence of eutrophication on Ag trophic transfer is dependent on the degree to which each kinetic parameter is affected by nutrient enrichments.
Erneuerung lokaler Spielräume
Authors: Buchecker Matthias , Berz Thomas
Published: March 2010

Involving the public in decision making is a common concern of policymakers and scientists. In the reality of planning praxis, however, the opposite tendency can be observed: the local residents increasingly withdraw from the local public life. Our investigations in two periurban communities show that this withdrawal is not primarily caused by the lack of suitable opportunities for the residents to participate in shaping the local public place. In order to revive public life and promote a need oriented community development, new informal instruments are needed for the residents to express their individual needs without jeopardising their social integration.
Regionalökonomische Bedeutung größerer Behinderteneinrichtungen
Authors: Becker Wolfgang , Rothenberger Dieter
Published: March 2010

Numerous studies into the impacts for regional economies emanating from infrastructure facilities — and especially from educational facilities — have demonstrated conclusively that such facilities are capable of generating both positive and stimulating effects on regional economies. Hitherto no comparable studies have been available for the field of social infrastructure, and in particular relating to facilities dedicated to helping, nursing and caring for people with disabilities. In the first empirical study of this type the focus is on the economic significance of larger-scale facilities for the disabled for the economy of the surrounding area, in this case based on the example of the Dominikus Ringeisen-Werk (DRW) in Bavaria. The key finding resulting from this study is that major facilities for the disabled of this type are indeed the source of a very considerable stimulus for the region in which they are located.
Standort- und Flächentrends bei Einzelhandelsgroßprojekten
Authors: Bleyer Burkhard
Published: March 2010

Developments in the type and size of retail operations and outlets are bringing with them changes to the spatialstructure pattern of what in Germany are known as “central places”. This article describes the spatial effects of these locational patterns on the central-place functions of city centres, along with the instruments of planning control available for state-level, regional and local development planning, and goes on to set out the areas of action open to spatial planning and to consider the increasingly important role being played by consensual processes. In the face of the challenges facing towns and cities as a result of the enormous dynamics in the retail sector, there is now a need for new, inter-authority planning instruments.
Rand, Grenze, Übergang: Landschaftsgrenzen als Ansatz räumlicher Planung im Umland
Authors: Clemens Corinna , Clemens Ariane
Published: March 2010

Even if the fate of cities is not — as is sometimes claimed- decided in the areas surrounding them, the suburban zones of cities do nonetheless have a pivotal role to play in the future development of agglomerations. If the contribution which the regional planning system wishes to make to this process is to ensure that greater weight is attached in future to the goals of ecological, social and economic sustainability, it will have to come up with strategies which meet the needs of these areas. In order to achieve this, it requires devices which it can draw on to structure the attributes of this hinterland and thus to render them communicable. This article explains how the settlement boundaries, land-use boundaries and transition zones found in the environs of cities may represent suitable approaches for spatial planning.
Beschreibung städtischer Teilräume mittels Oberflächenstrukturen
Authors: Weber Jörg , Sandtner Martin
Published: March 2010

The urban ecology of a town is shaped to a very considerable extent by the fabric of built structures and spaces (referred to here as surface structures) in the various sections of the urban territory. This paper presents a classificatory code developed for the purpose of mapping such structures and spaces and describes the cartographic procedure employed. This code can be used for the analogue/visual interpretation of large-scale aerial photographs. The authors draw on experience gathered in the course of a land survey conducted in 1988 for the territory of Munich, the Bavarian state capital, subsequently up-dated in 1996. The main focus of the forms of classification described is on issues of urban ecology relating to the mapping, analysis and evaluation of sustainable urban development.
Auf dem Wege zur Raumfinanzpolitik?
Authors: Mäding Heinrich
Published: March 2010

Policy and practice perspective
Flächennutzungsplanung in China — eine andere Welt
Authors: Zimmermann Horst
Published: March 2010

Policy and practice perspective
Die altersselektive Abwanderung aus Ostdeutschland
Authors: Mai Ralf
Published: March 2010

In this contribution the out-migration from Eastern to Western Germany from 1991 to 2004 is analysed. The focus lies on its age-selectivity, i.e. the diverse age-composition of migration by direction and intensity. After an overview on the migration flows between Eastern and Western Germany the age-selectivity is analysed regarding time, sex and space. A simulation of the age-structural effects of the Eastern German out-migration closes the analysis.
Optimierung strategischer Erfolgspotenziale in Prozessen zur Regionalentwicklung
Authors: Pollermann Kim
Published: March 2010

This article deals about successful ways of co-operative planning for regional development and about strategical success potentials which are able to give orientation in such processes. After an introduction about the problem-background and the type of investigation follows a description of the term planning-strategy. Results of evaluations of case studies are shown with a description of factors of success and obstacles. After the identification of strategical success potentials, impact factors between these potentials are discussed. Finally recommendations about the design of planning-strategies are given.
Naturschutzfachliches Flächenmanagement durch regionale Flächenpools
Authors: Jessel Beate
Published: March 2010

Grouping compensation measures from impact regulation in compensation pools has gained in importance recently not only on a local municipal but also on a regional level. The example of the “Flächenagentur Kulturlandschaft Mittlere Havel” in Brandenburg, which meanwhile is operating area-wide within this Federal State, serves to demonstrate different aspects that are relevant for a regional management of areas for purposes of nature conservation. In particular, it becomes apparent that for establishing a regional management of areas for nature conservation it is essential to choose the appropriate organisation form and that compensation pools may contribute to the implementation of concepts for nature conservation on a regional level. To assure an appropriate integration into extensive spatial relations, within the instruments of spatial planning above all landscape framework plans should stronger attend to this subject by setting respective targets and priorities.
Flächeninanspruchnahme durch Windkraftanlagen
Authors: Schmitt Maria , Dosch Fabian , Bergmann Eckhard
Published: March 2010

Policy and practice perspective
Das uneingeschränkte Abweichungsrecht nach Art. 72 Abs. 3 GG
Authors: Ritter Ernst-Hasso
Published: March 2010

Policy and practice perspective
Impact of Peritoneal Dialysis Versus Hemodialysis on Incidence of Intra‐abdominal Infection After Simultaneous Pancreas–Kidney Transplant
Authors: Padillo‐Ruiz Javier , Arjona‐Sánchez Alvaro , Muñoz‐Casares Cristobal , Ruiz‐Rabelo Juan , Navarro Maria Dolores , Regueiro Juan C.
Published: March 2010

Background

Whether peritoneal dialysis is a risk factor for the development of intra‐abdominal infection after simultaneous pancreas–kidney (SPK) transplantation is controversial.

Methods

We investigated the incidence of intra‐abdominal infection and graft survival rates in 100 patients who underwent SPK transplantation. Prior to transplantation, 25 patients received peritoneal dialysis (PD) and 75 received hemodialysis (HD); mean duration of dialysis was 25 ± 35 months and 17 ± 10 months, respectively.

Results

The two groups displayed similar gender distribution, cold ischemia time, dialysis duration, diabetes duration, and method of exocrine drainage. Intra‐abdominal infections developed in 23 patients in the HD group (30%) and in 6 (24%) patients in the PD group (P = 0.41). In the HD group, 61% of patients with intra‐abdominal infections had grades 3 and 4 complications requiring surgery, compared with only 33% in the PD group. The 1‐year pancreas graft survival rate was 88% for HD and 94% for PD (P = 0.67) (mean follow‐up = 55 ± 38 months). There were no significant intergroup differences in acute rejection episodes, kidney graft survival rates, or length of hospital stay.

Conclusions

In our experience, PD prior to SPK transplantation is not associated with increased incidence of intra‐abdominal infection compared to HD.
A Meta‐Analysis of After‐School Programs That Seek to Promote Personal and Social Skills in Children and Adolescents
Authors: Durlak Joseph A. , Weissberg Roger P. , Pachan Molly
Published: March 2010

A meta‐analysis of after‐school programs that seek to enhance the personal and social skills of children and adolescents indicated that, compared to controls, participants demonstrated significant increases in their self‐perceptions and bonding to school, positive social behaviors, school grades and levels of academic achievement, and significant reductions in problem behaviors. The presence of four recommended practices associated with previously effective skill training (SAFE: sequenced, active, focused, and explicit) moderated several program outcomes. One important implication of current findings is that ASPs should contain components to foster the personal and social skills of youth because youth can benefit in multiple ways if these components are offered. The second implication is that further research is warranted on identifying program characteristics that can help us understand why some programs are more successful than others.
More Than Attendance: The Importance of After‐School Program Quality
Authors: Hirsch Barton J. , Mekinda Megan A. , Stawicki JulieAnn
Published: March 2010

A central theme of the articles featured in this issue is the need to improve the quality of after‐school programs. In this commentary, we discuss why student engagement, program characteristics and implementation, staff training, and citywide policy are key considerations in the effort to define and achieve high quality programs for youth.
Inside the Black Box: Assessing and Improving Quality in Youth Programs
Authors: Yohalem Nicole , Wilson-Ahlstrom Alicia
Published: March 2010

Over the past decade, structured programming for children and youth during the non‐school hours has expanded exponentially. A confluence of recent research studies and program evaluations backs the publicly perceived notion that after‐school programs can positively influence important developmental and learning outcomes. The rapid expansion of the field and the potential of programs to contribute to child and youth development have made defining what high quality programs look like and learning how to improve program quality key challenges facing the field. This paper describes what is known about the relation between youth program quality and youth developmental outcomes, summarizes different quality assessment tools being used in the field, and discusses how such tools are being used to drive systemic quality improvement efforts.
What Do Genetic Counselors Learn on the Job? A Qualitative Assessment of Professional Development Outcomes
Authors: Runyon Marie , Zahm Kimberly W. , Veach Patricia McCarthy , MacFarlane Ian M. , LeRoy Bonnie S.
Published: March 2010

Professional development is an important goal for professionals in human service fields such as counseling, teaching, and nursing. However, there are relatively few published papers on this topic specific to genetic counselors, and no studies systematically examine the outcomes of their professional development. This study was designed to investigate genetic counselors’ perceptions of their post‐degree learning and to compare themes in their learning to those of psychotherapist professional development models. Two hundred ninety‐three genetic counselors completed the demographics portion of an anonymous online survey, and of these, 185 also responded to at least one of two open‐ended items: What is the most important thing you have learned about yourself in your practice as a genetic counselor? and What advice would you give to genetic counseling students just starting their career? An interpretative content‐analysis method was used to extract three major themes: Intrapersonal lessons, Interpersonal lessons, and Professional lessons. Training and practice implications and research recommendations are provided.
Influential Factors of Player's Loyalty toward Online Games for Achieving Commercial Success
Authors: Lee Cheng-Wen
Published: March 2010

A particularly interesting phenomenon that has arisen through Internet community is the virtual world style of online game. This paper presents a research framework for identifying the influential factors of player's loyalty toward online games, with emphasis on player's loyalty for achieving commercial success. The main methodologies are canonical correlation analysis and stepwise regression analysis employing 245 questionnaires collected. As an important insight, this research reveals that motives of player's participation are significantly related to business operation and game design, and further have a positive effect upon player's loyalty – addictive behavior and flow experience. Under close observation of the sub-criteria factors, role-playing and achievement play crucial roles in the influencing player's engagement process. Contrarily, storyline and public phrase are less relevant to player's loyalty. Finally, this study discusses the managerial implications regarding these findings and future research avenues.
Phospholipid scramblase: An update
Authors: Bevers Edouard M. , Williamson Patrick L.
Published: March 2010

The best understood consequence of the collapse of lipid asymmetry is exposure of phosphatidylserine (PS) in the external leaflet of the plasma membrane bilayer, where it is known to serve at least two major functions: providing a platform for development of the blood coagulation cascade and presenting the signal that induces phagocytosis of apoptotic cells. Lipid asymmetry is collapsed by activation of phospholipid scramblase(s) that catalyze bidirectional transbilayer movement of the major classes of phospholipid. The protein corresponding to this activity is not yet known. Observations on cells from patients with Scott syndrome, a rare hereditary bleeding disorder resulting from impaired lipid scrambling, have shown that there are multiple activation pathways that converge on scramblase activity.
The Siting of Metalwork Hoards in the Bronze Age of South-East England
Authors: Yates David , Bradley Richard
Published: March 2010

The paper discusses the siting of Middle and Late Bronze Age hoards in south Hampshire, Sussex and parts of Surrey and Kent. It presents the results of fieldwork at the findspots of a hundred metalwork deposits and discusses the most informative ways of studying them on the ground. On the coastal plain the hoards were not far from occupation sites, and can be associated with evidence of burnt mounds and occasionally with field systems. That was less common on the chalk. Throughout the study area these deposits were normally located along watercourses, with a special emphasis on small areas of ground beside, or overlooking springs and confluences. It seems as if the deposition of bronze metalwork was governed by certain conventions. For that reason it may be possible to predict the pattern of future discoveries.
The effect of thermal expansion on diffusion flame instabilities
Authors: MATALON M. , METZENER P.
Published: March 2010

In this paper we examine the effect of thermal expansion on the stability of a planar unstrained diffusion flame and provide a comprehensive characterization of diffusive-thermal instabilities while realistically accounting for density variations. The possible patterns that are likely to be observed as a result of differential and preferential diffusion are identified for a whole range of parameters including the distinct Lewis numbers associated with the fuel and oxidizer, the initial mixture strength and the flow conditions. Although we find that thermal expansion has a marked influence on flame instability, it does not play a crucial role as it does in premixed combustion. It primarily affects the parameter regime associated with the onset of the instabilities and the growth rate of the unstable modes. Perhaps the most surprising result is that its has a different influence on the various modes of instability – a destabilizing influence on the formation of cellular structures and a stabilizing influence on the onset of oscillations.
The sensitivity of convection from a horizontal boundary to the distribution of heating
Authors: COMAN M. A. , GRIFFITHS R. W. , HUGHES G. O.
Published: March 2010

Results of experimental and numerical studies are presented for a class of horizontal thermal convection in a long box forced at one horizontal boundary by two regions of destabilizing buoyancy flux separated by a region of stabilizing buoyancy flux. The steady-state circulation with zero net heat input is examined. The circulation generally involves two plumes, one at each end of the box, which drive overturning throughout the domain. The flow is classified into three regimes according to the pattern of interior circulation and depending on the relative heat input applied to the two destabilizing regions. Unequal heat inputs can double the interior stratification above that created by symmetric flow with two identical plumes, and when the heat inputs differ by more than 10%, the interior stratification is set by the stronger plume. The arrangement of boundary forcing broadly parallels the distribution of the zonally averaged surface cooling and heating in the Northern and Southern Hemispheres, and the results suggest that ocean overturning circulations may be sensitive to interhemispheric differences in the buoyancy inputs.
Landslide tsunamis propagating around a conical island
Authors: RENZI E. , SAMMARCO P.
Published: March 2010

An analytical forced two-horizontal-dimension model is derived to investigate landslide tsunamis propagating around a conical island lying on a flat continental platform. Separation of variables and Laplace transform are used to obtain the free-surface elevation in the whole domain and the runup at the shoreline in terms of confluent Heun functions. The main properties of these functions and their asymptotic behaviour for large parameters are investigated. Expression of the transient leading wave travelling offshore is also derived. The distinguishing physical features of landslide tsunamis propagating in a round geometry are then pointed out and compared with those of landslide tsunamis propagating along a straight coast. Analytical results satisfactorily agree with available experimental data.
Events before droplet splashing on a solid surface
Authors: MANI MADHAV , MANDRE SHREYAS , BRENNER MICHAEL P.
Published: March 2010

A high-velocity (≈1 ms−1) impact between a liquid droplet (≈1 mm) and a solid surface produces a splash. Classical observations traced the origin of this splash to a thin sheet of fluid ejected near the impact point, though the fluid mechanical mechanism leading to the sheet is not known. Mechanisms of sheet formation have heretofore relied on initial contact of the droplet and the surface. In this paper, we theoretically and numerically study the events within the time scale of about 1 μs over which the coupled dynamics between the gas and the droplet becomes important. The droplet initially tries to contact the substrate by either draining gas out of a thin layer or compressing it, with the local behaviour described by a self-similar solution of the governing equations. This similarity solution is not asymptotically consistent: forces that were initially negligible become relevant and dramatically change the behaviour. Depending on the radius and impact velocity of the droplet, we show that the solution is overtaken by initially subdominant physical effects such as the surface tension of the liquid–gas interface or viscous forces in the liquid. At low impact velocities surface tension stops the droplet from impacting the surface, whereas at higher velocities viscous forces become important before surface tension. The ultimate dynamics of the interface once droplet viscosity cannot be neglected is not yet known.
Short-term forecasts and scaling of intense events in turbulence
Authors: DONZIS D. A. , SREENIVASAN K. R.
Published: March 2010

Extreme events such as intense tornadoes and huge floods, though infrequent, are particularly important because of their disproportionate impact. Our ability to forecast them is poor at present. Large events occur also in intermittent features of turbulent flows. Some dynamical understanding of these features is possible because the governing equations are known and can be solved with good accuracy on a computer. Here, we study large-amplitude events of turbulent vorticity using results from direct numerical simulations of isotropic turbulence in conjunction with the vorticity evolution equation. We show that the advection is the dominant process by which an observer fixed to the laboratory frame perceives vorticity evolution on a short time scale and that the growth of squared vorticity during large excursions is quadratic in time when normalized appropriately. This result is not inconsistent with the multifractal description and is simpler for present purposes. Computational data show that the peak in the viscous term of the vorticity equation can act as a precursor for the upcoming peak of vorticity, forming a reasonable basis for forecasts on short time scales that can be estimated simply. This idea can be applied to other intermittent quantities and, possibly, more broadly to forecasting other extreme quantities, e.g. in seismology.
Convective instabilities during the solidification of an ideal ternary alloy in a mushy layer
Authors: ANDERSON DANIEL M. , McFADDEN GEOFFREY B. , CORIELL SAM R. , MURRAY BRUCE T.
Published: March 2010

We consider a model for the solidification of an ideal ternary alloy in a mushy layer that incorporates the effects of thermal and solutal diffusion, convection and solidification. Our results reveal that although the temperature and solute fields are constrained to the liquidus surface of the phase diagram, the system still admits double-diffusive modes of instability. Additionally, modes of instability exist even in situations in which the thermal and solute fields are each individually stable from a static point of view. We identify these instabilities for a general model in which the base-state solution and its linear stability are computed numerically. We then highlight these instabilities in a much simpler model that admits an analytical solution.
On the mechanisms of icicle evolution
Authors: NEUFELD JEROME A. , GOLDSTEIN RAYMOND E. , WORSTER M. GRAE
Published: March 2010

We present a study of a cylinder of ice melting in warm air in order to quantify the heat-transfer mechanisms controlling the evolution of its shape, which are inherent in a range of phenomena involving phase change and fluid flow. Motivated by the initial melting at the top of a flat-topped cylinder of ice, we analyse laminar, natural convection above a cooled, finite, horizontal plate (or below a heated, finite, horizontal plate) and show that, to a very good approximation, the partial-differential, boundary-layer equations can be separated with self-similar vertical profiles scaled by the boundary-layer thickness. We find that the horizontal evolution of the boundary-layer thickness is governed by equations describing a steady, viscous gravity current fed by diffusive entrainment, and therefore describe such flows asdiffusive gravity currents. We first use the predictions of our model to examine previous experimental results in two dimensions. Our experimental results relating to the melting of ice in air are then compared with predictions based on our analysis of the axisymmetric thermal boundary layer. This comparison confirms the vertical thermal structure and shows that melting is governed in roughly equal measure by heat transfer from the air, the latent heat of condensation of water vapour, and the net radiative heat transfer from the surroundings to the ice.
Effect of gravity on the stability of thermocapillary convection in a horizontal fluid layer
Authors: CHAN CHO LIK , CHEN C. F.
Published: March 2010

Smith & Davis (J. Fluid Mech., vol. 132, 1983, pp. 119–144) considered the stability of thermocapillary convection in a horizontal fluid layer with an upper free surface generated by a horizontal temperature gradient. They showed that for a return-flow velocity profile, the convection will become unstable in the hydrothermal mode with waves propagating upstream obliquely. Their findings provided a theoretical explanation for the defects often found in crystals grown by the floating-zone technique and in thin-film coating processes. Their predictions were verified experimentally by Riley & Neitzel (J. Fluid Mech., vol. 359, 1998, pp. 143–164) in an experiment with 0.75 mm thick layer of silicone oil. Their results with 1 and 1.25 mm thick layers show that as the thickness of the layer is increased, the angle of propagation, the frequency of oscillation and the phase speed of the hydrothermal wave instability decrease, while the wavelength stays nearly constant. We have extended the linear stability analysis of the problem with the effect of gravity included. It is found that when the Grashof number Gr is increased from zero, the angle of propagation first increases slightly, reaches a maximum and then decreases steadily to zero at Gr = 18. The phase speed, the frequency of oscillation and the wavelength of the instability waves all decrease with increasing Grashof number. For Gr larger than 18, there is the onset of the instability into travelling transverse waves. We have also carried out energy analysis at the time of the instability onset. It is found that the major contribution to the energy of the disturbances is from the surface-tension effect. As the gravitational effect is increased, there is a reduction in the kinetic energy supply to sustain the motion of the disturbances. We also found that it requires more kinetic energy to sustain the hydrothermal mode of instability than that required for the travelling transverse mode of instability. As a result, with increasing Grashof number, the kinetic energy available for the disturbances decreases, causing the angle of propagation to gradually decrease until finally reaching zero at Gr = 18.
Turbulent drag reduction and multistage transitions in viscoelastic minimal flow units
Authors: XI LI , GRAHAM MICHAEL D.
Published: March 2010

The observation that addition of a minute amount of flexible polymers to fluid reduces turbulent friction drag is well known. However, many aspects of this drag reduction phenomenon are not well understood; in particular, the origin of the maximum drag reduction (MDR) asymptote, a universal upper limit on drag reduction by polymers, remains an open question. This study focuses on the drag reduction phenomenon in the plane Poiseuille geometry in a parameter regime close to the laminar–turbulent transition. By minimizing the size of the periodic simulation box to the lower limit for which turbulence persists, the essential self-sustaining turbulent motions are isolated. In these ‘minimal flow unit’ (MFU) solutions, a series of qualitatively different stages consistent with previous experiments is observed, including an MDR stage where the mean flow rate is found to be invariant with respect to changing polymer-related parameters. Before the MDR stage, an additional transition exists between a relatively low degree (LDR) and a high degree (HDR) of drag reduction. This transition occurs at about 13%–15% of drag reduction and is characterized by a sudden increase in the minimal box size, as well as many qualitative changes in flow statistics. The observation of LDR–HDR transition at less than 15% drag reduction shows for the first time that it is a qualitative transition instead of a quantitative effect of the amount of drag reduction. Spatio-temporal flow structures change substantially upon this transition, suggesting that two distinct types of self-sustaining turbulent dynamics are observed. In LDR, as in Newtonian turbulence, the self-sustaining process involves one low-speed streak and its surrounding streamwise vortices; after the LDR–HDR transition, multiple streaks are present in the self-sustaining structure and complex intermittent behaviour of the streaks is observed. This multistage scenario of LDR–HDR–MDR recovers all key transitions commonly observed and studied at much higher Reynolds numbers.
A faecal analysis of helminth infections in wild and captive wolves,Canis lupusL., in Poland
Authors: Szafrańska E. , Wasielewski O. , Bereszyński A.
Published: March 2010

One hundred and three samples of faeces of reared grey wolves from four locations (Stobnica Park and Zoological Gardens in Bydgoszcz, Wrocław and Cracow) and twenty-six samples of faeces from two free-roaming packs of grey wolf (Canis lupusL.) in Piła (Forest Divisions: Borne Sulinowo, Czarnobór, Jastrowo) and Zielona Góra (Forest Divisions: Torzym, Krosno Odrzańskie) were collected between 2005 and 2007. Helminth eggs were detected in 78.6% of faecal samples of reared grey wolves and in 88.4% of those of free-roaming wolves. The trematodeAlaria alata(80.1%) and nematodesEucoleus aerophilus(23.1%) andSpirocerca lupi(11.5%) were only detected from wild packs of wolves and the nematodesAncylostoma caninum(35.9%),Trichuris vulpis(15.5%) andToxocara canis(3.9%) were only detected from reared wolves. Differences were observed in the prevalence and composition of helminth fauna between reared and wild grey wolves and our results are compared with those from studies within Poland and elsewhere in Europe.
Sympatric and allopatric experimental infections of the planorbid snailGyraulus chinensiswith miracidia ofEuparyphium albuferensis(Trematoda: Echinostomatidae)
Authors: Muñoz-Antoli C. , Marín A. , Trelis M. , Toledo R. , Esteban J.-G.
Published: March 2010

An experimental infection with echinostomatid miracidia in sympatric or ‘local’ vs. allopatric or ‘away’ snail combinations, as a model to examine parasite compatibility, was carried out. We employedEuparyphium albuferensismiracidia to infectGyraulus chinensissnails, from three different natural parks: Albufera (Valencia, Spain); the Ebro Delta (Tarragona, Spain) and Coto de Doñana (Huelva, Spain). Insignificant differences between the three snail strains were noted for the infection rate and the rhythm of daily cercarial production. However, a significantly higher total cercarial production per snail, patent period and life span were observed in local snails. The different infection characteristics in the threeG. chinensisstrains considered reveal thatE. albuferensismiracidia demonstrate local adaptation.
Northern exposure: opportunities and challenges for tourism development in Torngat Mountains National Park, Labrador, Canada
Authors: Maher Patrick T. , Lemelin R. Harvey
Published: March 2010

Torngat Mountains National Park (TMNP) is Canada's newest national park, and was established in 2005. The development of the park has mirrored a change in mandate for the agency that manages it, Parks Canada. Since 2005 Parks Canada has sought to focus on ‘proactively facilitate[ing] opportunities for meaningful and memorable visitor experiences’, complimentary to maintaining the protection of ecological integrity and providing education (Parks Canada 2005, no page numbers). Under the auspices of this new multi-faceted mandate, this research note will examine the current state of tourism in TMNP, and will also evaluate some of the opportunities and challenges for the future. Within Parks Canada's Visitor experience vision 2015 statement, understanding tourism delivery in the present and future are important components of its mission, as is engagement with external partners to assist in this process. The analysis of tourism development in TMNP for this note comes from the authors' two week research trips to the park in August 2008 and July 2009, undertaken to assist Parks Canada to evaluate their current visitor experience activities and future options.
Genetic and environmental influences on internalizing psychopathology vary as a function of economic status
Authors: South S. C. , Krueger R. F.
Published: March 2010

Background

Different theories of the link between socio-economic status (SES) and mental illness have been postulated. In particular, two theories of this association, social causation and social selection, differ in the implied causal pathway. The authors employ behavior genetic modeling to consider evidence for both social selection and social causation in the relationship between income variation and internalizing disorders.

Method

Behavior genetic modeling was used to estimate the presence of gene–environment interaction (GxE, social causation) in the presence of gene–environment correlation (rGE, social selection). Participants were members of a sample of 719 twin pairs from the Midlife in the United States study. Four internalizing (INT) syndromes were assessed: major depression (MD); generalized anxiety disorder (GAD); panic attacks (PA); neuroticism (N). SES was measured with total family household income.

Results

One factor best accounted for the variance shared between MD, GAD, PA and N. The etiology of variation in INT changed from high to low levels of income, with unique environmental factors playing a larger role in INT variation at lower levels of income. Across levels of income, rGE between income and INT was modest (low incomera=0.39 to high incomera=0.54), implying a selection process operating through genetic effects linking lower income with INT psychopathology.

Conclusions

Findings support social causation by suggesting that low income contributes significantly to environmental variation in INT. Modest support was found for social selection, but should be extended using longitudinal designs. Effective interventions for internalizing psychopathology may differ depending on income.
The pathways to mental health care of first-episode psychosis patients: a systematic review
Authors: Anderson K. K. , Fuhrer R. , Malla A. K.
Published: March 2010

Background

Although there is agreement on the association between delay in treatment of psychosis and outcome, less is known regarding the pathways to care of patients suffering from a first psychotic episode. Pathways are complex, involve a diverse range of contacts, and are likely to influence delay in treatment. We conducted a systematic review on the nature and determinants of the pathway to care of patients experiencing a first psychotic episode.

Method

We searched four databases (Medline, HealthStar, EMBASE, PsycINFO) to identify articles published between 1985 and 2009. We manually searched reference lists and relevant journals and used forward citation searching to identify additional articles. Studies were included if they used an observational design to assess the pathways to care of patients with first-episode psychosis (FEP).

Results

Included studies (n=30) explored the first contact in the pathway and/or the referral source that led to treatment. In 13 of 21 studies, the first contact for the largest proportion of patients was a physician. However, in nine of 22 studies, the referral source for the greatest proportion of patients was emergency services. We did not find consistent results across the studies that explored the sex, socio-economic, and/or ethnic determinants of the pathway, or the impact of the pathway to care on treatment delay.

Conclusions

Additional research is needed to understand the help-seeking behavior of patients experiencing a first-episode of psychosis, service response to such contacts, and the determinants of the pathways to mental health care, to inform the provision of mental health services.