bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal and spatial variation in water availability drive habitat associations in a tropical forest
Authors: Comita Liza S. , Engelbrecht Bettina M. J.
Published: September 2009

Associations with topographic units or soil types that vary in water availability are widespread in plant communities and are one of the main structuring aspects for local species distribution patterns, yet the underlying mechanisms are poorly understood. We hypothesized that differential seedling performance across habitats, particularly during the dry season, leads to habitat associations in seasonal tropical forests. We expected this pattern to be most pronounced in particularly dry years, such as those associated with El Niño Southern Oscillation (ENSO) events. We assessed performance of 36 native tree and shrub species in a moist forest in central Panama across the dry and wet seasons in two topographic habitat types during a year in which dry‐season precipitation was reduced due to an ENSO event. At the community level, we found lower growth and higher mortality in the dry season relative to the wet season and higher mortality in the drier plateau habitat relative to the wetter slope habitat. There was large variation in species' responses to season and habitat. Species' mortality and growth rates were significantly correlated with experimentally assessed drought sensitivity, but only during the dry season in the plateau habitat. Slope specialists had significantly higher survival, but not growth, in the slope vs. plateau habitat during the dry season. In contrast, plateau specialists showed no performance differences between habitats. The data suggest that associations with plateau habitats result from a numerical advantage of drought‐tolerant species in dry habitats in which seedlings of drought‐sensitive species are unable to persist. Overall, our results support the idea that seasonal and spatial variation in water availability, particularly in dry years, drive seedling dynamics, which in turn shape local species distributions. Predicted shifts in rainfall patterns caused by global and regional climate change are therefore expected to alter the dynamics, composition, and diversity of seasonal tropical forests.
Flux of aquatic insect productivity to land: comparison of lentic and lotic ecosystems
Authors: Gratton Claudio , Zanden M. Jake Vander
Published: September 2009

Recently, food web studies have started exploring how resources from one habitat or ecosystem influence trophic interactions in a recipient ecosystem. Benthic production in lakes and streams can be exported to terrestrial habitats via emerging aquatic insects and can therefore link aquatic and terrestrial ecosystems. In this study, we develop a general conceptual model that highlights zoobenthic production, insect emergence, and ecosystem geometry (driven principally by area‐to‐edge ratio) as important factors modulating the flux of aquatic production across the ecosystem boundary. Emerging insect flux, defined as total insect production emerging per meter of shoreline (g C·m−1·yr−1) is then distributed inland using decay functions and is used to estimate insect deposition rate to terrestrial habitats (g C·m−2·yr−1).

Using empirical data from the literature, we simulate insect fluxes across the water–land ecosystem boundary to estimate the distribution of fluxes and insect deposition inland for lakes and streams. In general, zoobenthos in streams are more productive than in lakes (6.67 vs. 1.46 g C·m−2·yr−1) but have lower insect emergence to aquatic production ratios (0.19 vs. 0.30). However, as stream width is on average smaller than lake radius, this results in flux (F) estimates 2½ times greater for lakes than for streams. Ultimately, insect deposition onto land (within 100 m of shore) adjacent to average‐sized lakes (10‐ha lakes, 0.021 g C·m−2·yr−1) is greater than for average‐sized streams (4 m width, 0.002 g C·m−2·yr−1) used in our comparisons. For the average lake (both in size and productivity), insect deposition rate approaches estimates of terrestrial secondary production in low‐productivity ecosystems (e.g., deserts and tundra, ≈0.07 g C·m−2·yr−1). However, larger lakes (1300 ha) and streams (16 m) can have average insect deposition rates (≈0.01–2.4 g C·m−2·yr−1) comparable to estimates of secondary production of more productive ecosystems such as grasslands. Because of the potentially large inputs of emerging aquatic insects into terrestrial habitats, ecosystem processes and terrestrial consumers can be influenced by insect inputs. The relative contribution of lakes and streams to this flux will vary among landscapes depending on the number and size of these ecosystems types on the landscape.
For ant‐protected plants, the best defense is a hungry offense
Authors: Ness J. H. , Morris W. F. , Bronstein Judith L.
Published: September 2009

Animal foraging has been characterized as an attempt to maximize the intake of carbon and nitrogen at appropriate ratios. Plant species in over 90 families produce carbohydrate‐rich extrafloral nectar (EFN), a resource attractive to ants and other omnivorous insects. This attraction can benefit the plant if those arthropods subsequently attack herbivores. This protective response has been attributed to the increased visitation and “ownership” of plants that provide a predictable source of fuel. Here, we propose and test an alternative (but non‐mutually exclusive) hypothesis, that access to C‐rich carbohydrates increases the ants' desire for N‐rich protein and hence the likelihood that they will attack herbivorous insects on the host plant. This “deficit hypothesis” would be rejected if (1) EFN were itself a sufficiently balanced food source in terms of C and N, (2) ant dietary preferences were similar in the presence vs. absence of EFN, (3) protein‐hungry ants were not more predaceous, or (4) ants provided access to protein were more aggressive toward potential prey items than were ants provided access to carbohydrates. We test these predictions in a protective mutualism between a guild of desert ants and the barrel cactusFerocactus wislizeni. C:N ratios of EFN exceeded that of ants or potential prey items by an order of magnitude (i.e., EFN is an N‐poor food for ants). Baiting studies demonstrated that plant‐tending ant species recruited more workers to N‐rich protein baits than to C‐rich sugar baits; this difference was more pronounced when the ants had access toF. wislizeniEFN. From these data, we infer that protein is a valuable resource and that its relative value increases when carbohydrates are readily available. Moreover, ant colonies provided access to supplemental carbohydrates responded more aggressively to surrogate herbivores than did control colonies (to which no additional resources were provided) or colonies provided protein. These results support the predictions of the “deficit” hypothesis, wherein plant protection is elicited by plant‐mediated dietary imbalances.
Modeling survival at multi‐population scales using mark–recapture data
Authors: Grosbois V. , Harris M. P. , Anker-Nilssen T. , McCleery R. H. , Shaw D. N. , Morgan B. J. T. , Gimenez O.
Published: September 2009

The demography of vertebrate populations is governed in part by processes operating at large spatial scales that have synchronizing effects on demographic parameters over large geographic areas, and in part, by local processes that generate fluctuations that are independent across populations. We describe a statistical model for the analysis of individual monitoring data at the multi‐population scale that allows us to (1) split up temporal variation in survival into two components that account for these two types of processes and (2) evaluate the role of environmental factors in generating these two components. We derive from this model an index of synchrony among populations in the pattern of temporal variation in survival, and we evaluate the extent to which environmental factors contribute to synchronize or desynchronize survival variation among populations.

When applied to individual monitoring data from four colonies of the Atlantic Puffin (Fratercula arctica), 67% of between‐year variance in adult survival was accounted for by a global spatial‐scale component, indicating substantial synchrony among colonies. Local sea surface temperature (SST) accounted for 40% of the global spatial‐scale component but also for an equally large fraction of the local‐scale component. SST thus acted at the same time as both a synchronizing and a desynchronizing agent. Between‐year variation in adult survival not explained by the effect of local SST was as synchronized as total between‐year variation, suggesting that other unknown environmental factors acted as synchronizing agents.

Our approach, which focuses on demographic mechanisms at the multi‐population scale, ideally should be combined with investigations of population size time series in order to characterize thoroughly the processes that underlie patterns of multi‐population dynamics and, ultimately, range dynamics.
Does hunting regulate cougar populations? A test of the compensatory mortality hypothesis
Authors: Cooley Hilary S. , Wielgus Robert B. , Koehler Gary M. , Robinson Hugh S. , Maletzke Benjamin T.
Published: September 2009

Many wildlife species are managed based on the compensatory mortality hypothesis, which predicts that harvest mortality (especially adult male mortality) will trigger density‐dependent responses in reproduction, survival, and population growth caused via reduced competition for resources. We tested the compensatory mortality hypothesis on two cougar (Puma concolor) populations in Washington, USA (one heavily hunted and one lightly hunted). We estimated population growth, density, survival, and reproduction to determine the effects of hunting on cougar population demography based on data collected from 2002 to 2007. In the heavily hunted population, the total hunting mortality rate (mean ± SD) was 0.24 ± 0.05 (0.35 ± 0.08 for males, 0.16 ± 0.05 for females). In the lightly hunted population, the total hunting mortality rate was 0.11 ± 0.04 (0.16 ± 0.06 for males, 0.07 ± 0.05 for females). The compensatory mortality hypothesis predicts that higher mortality will result in higher maternity, kitten survival, reproductive success, and lower natural mortality. We found no differences in rates of maternity or natural mortality between study areas, and kitten survival was lower in the heavily hunted population. We rejected the compensatory mortality hypothesis because vital rates did not compensate for hunting mortality. Heavy harvest corresponded with increased immigration, reduced kitten survival, reduced female population growth, and a younger overall age structure. Light harvest corresponded with increased emigration, higher kitten survival, increased female population growth, and an older overall age structure. Managers should not assume the existence of compensatory mortality when developing harvest prescriptions for cougars.
Local immigration, competition from dominant guilds, and the ecological assembly of high‐diversity pine savannas
Authors: Myers Jonathan A. , Harms Kyle E.
Published: September 2009

In high‐diversity communities, rare species encounter one another infrequently and therefore may compete more intensely with common species or guilds for limiting space and resources. In addition, rare species may be strongly recruitment limited because of their low abundances. Under these conditions, stochastic dispersal and immigration history can have an important influence on community structure. We tested the hypothesis that local immigration and competition from common, large‐stature guilds interact to structure local biodiversity in high‐diversity longleaf pine savanna groundcover assemblages (>30 species/m2). In two factorial field experiments, we increased local immigration by adding seeds of 38 mostly rare, small‐stature forbs and sedges to plots physically dominated by either a common, large‐stature bunchgrass or shrub species and to plots in which competition from these dominant guilds was reduced. We measured species richness and abundance at two spatial scales (0.01 and 0.25 m2) over two years. Immigration increased total species richness and richness of focal seed addition species regardless of levels of competition with bunchgrasses and shrubs, indicating that many rare, small‐stature species can recruit in the face of potential competition from dominant guilds. Removal of dominant guilds increased total and focal species richness in shrub‐dominated but not bunchgrass‐dominated plots. In addition, competition from both dominant guilds had no clear effect on rank–abundance distributions of focal species. Our results suggest a key role for dispersal assembly in structuring local biodiversity in this high‐diversity plant community, but the importance of this mechanism depends on the strength of local niche assembly involving competition from some, but not all, dominant guilds.
Detecting reactivity
Authors: Neubert Michael G. , Caswell Hal , Solow Andrew R.
Published: September 2009

By definition, ecological systems at a stable equilibrium eventually return to the equilibrium point following a small perturbation. In the short term, however, perturbations can grow. Equilibria that exhibit transient growth following perturbation are said to be reactive. In this report, we present a statistical method for detecting reactivity from multivariate time series. The test is simple and computationally tractable, and it can be applied to short time series. Its main limitation is that it is based on a model of population dynamics that is linear on a logarithmic scale. Our results suggest that the test is robust when the dynamics are nonlinear on the log scale but that it may incorrectly classify an equilibrium as reactive when the reactivity is close to zero.
Predator–spreaders: Predation can enhance parasite success in a planktonic host–parasite system
Authors: Cáceres Carla E. , Knight Christine J. , Hall Spencer R.
Published: September 2009

The “healthy herds” hypothesis suggests that selective predators, by acting as parasite sinks, may inhibit the start of epidemics and reduce prevalence of infection. Here, we describe a counter‐example using field patterns, experiments, and a model. The predator Chaoborus releases infective spores of a fungal parasite and, in doing so, may facilitate epidemics in Daphnia populations. In the field, epidemics occur in lakes with higher Chaoborus densities. Experiments revealed that nonselective Chaoborus release many of the spores contained in their prey. Since these released spores remain infective, this predator can catalyze epidemics when a lake's physical environment might otherwise impede them. Without Chaoborus, Daphnia dying of infection may sink to the lake bottom before releasing spores. A model tracking hosts and spores in the water column (where hosts contact spores) and in bottom sediments (where they cannot) illustrates this mechanism. Thus, by dispersing spores while feeding, this predator spreads disease. Many invertebrates are parasitized by obligately killing parasites, offering a variety of systems for additional tests of this “predator–spreader” hypothesis. In the meantime, this planktonic disease system prompts a very important, general warning: before we use predators to keep the herds healthy, we need to carefully think about the interface between predator feeding biology and the underlying epidemiology of wildlife disease.
Increased plant biomass in a High Arctic heath community from 1981 to 2008
Authors: Hudson J. M. G. , Henry G. H. R.
Published: September 2009

The Canadian High Arctic has been warming for several decades. Over this period, tundra plant communities have been influenced by regional climate change, as well as other disturbances. At a site on Ellesmere Island, Nunavut, Canada, we measured biomass and composition changes in a heath community over 13 years using a point‐intercept method in permanent plots (1995–2007) and over 27 years using a biomass harvest comparison (1981–2008). Results from both methods indicate that the community became more productive over time, suggesting that this ecosystem is currently in transition. Bryophyte and evergreen shrub abundances increased, while deciduous shrub, forb, graminoid, and lichen cover did not change. Species diversity also remained unchanged. Because of the greater evergreen shrub cover, canopy height increased. From 1995 to 2007, mean annual temperature and growing season length increased at the site. Maximum thaw depth increased, while soil water content did not change. We attribute the increased productivity of this community to regional warming over the past 30–50 years. This study provides the first plot‐based evidence for the recent pan‐Arctic increase in tundra productivity detected by satellite‐based remote‐sensing and repeat‐photography studies. These types of ground‐level observations are critical tools for detecting and projecting long‐term community‐level responses to warming.
Individual- and population-level effects of the synthetic musk, hhcb, on the deposit-feeding polychaete,Capitellasp. I
Authors: Ramskov Tina , Selck Henriette , Salvitod Daniel , Forbes Valery E.
Published: September 2009

A life table response experiment lasting 120 d was used to investigate the effects of the synthetic polycyclic musk HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8-hexamethylcyclopenta-γ-2-benzopyrane; 0, 1.5, 26, 123, and 168 mg/kg dry wt sediment) on the life history of the infaunal polychaete Capitella species I. The HHCB exposure showed no detectable effects on adult survival, age at first reproduction, length of the reproductive period, number of broods, individual worm body volumes, or body size-specific egestion rates. In contrast, HHCB significantly affected juvenile survival (≥123 mg/kg), maturation time (168 mg/kg), total number of eggs produced (≥26 mg/kg), and brood size (≥123 mg/kg) and marginally increased time between breeding attempts (≥26 mg/kg). A declining trend was observed for population growth rate with increasing HHCB concentrations, but differences between the control and exposed groups were not significant. Thus, despite detectable effects of HHCB on individual life-history traits, the results suggest that environmentally realistic concentrations of HHCB are not likely to reduce the growth rate of Capitella sp. I populations.
Emission of biocides from hospitals: Comparing current survey results with European Union default values
Authors: Tluczkiewicz Inga , Bitsch Annette , Hahn Stefan , Hahn Torsten
Published: September 2009

Under the European Union (EU) Biocidal Products Directive 98/8/EC, comprehensive evaluations on substances of the Third Priority List were conducted until 31 July 2007. This list includes, among other categories, disinfectants for human hygiene (e.g., skin and surface disinfection). For environmental exposure assessment of biocides, the EU emission scenarios apply. Currently available default values for disinfectants are based on consumption data from not more than 8 hospitals and were originally assembled for other purposes. To revalidate these default values, a survey on annual consumption data was performed in 27 German hospitals. These data were analyzed to provide consumption data per bed and day and per nurse and day for particular categories of active ingredients and were compared with default values from the EU emission scenario documents. Although several deviations were detected, an overall acceptable correspondence between Emission Scenario Documents default values and the current survey data was found. Integr Environ Assess Manag 2010;6:273–280. © 2009 SETAC
AGGRESSION AS POSITIVE REINFORCEMENT IN MICE UNDER VARIOUS RATIO‐ AND TIME‐BASED REINFORCEMENT SCHEDULES
Authors: May Michael E. , Kennedy Craig H.
Published: October 2009

There is evidence suggesting aggression may be a positive reinforcer in many species. However, only a few studies have examined the characteristics of aggression as a positive reinforcer in mice. Four types of reinforcement schedules were examined in the current experiment using male Swiss CFW albino mice in a resident—intruder model of aggression as a positive reinforcer. A nose poke response on an operant conditioning panel was reinforced under fixed‐ratio (FR 8), fixed‐interval (FI 5‐min), progressive ratio (PR 2), or differential reinforcement of low rate behavior reinforcement schedules (DRL 40‐s and DRL 80‐s). In the FR conditions, nose pokes were maintained by aggression and extinguished when the aggression contingency was removed. There were long postreinforcement pauses followed by bursts of responses with short interresponse times (IRTs). In the FI conditions, nose pokes were maintained by aggression, occurred more frequently as the interval elapsed, and extinguished when the contingency was removed. In the PR conditions, nose pokes were maintained by aggression, postreinforcement pauses increased as the ratio requirement increased, and responding was extinguished when the aggression contingency was removed. In the DRL conditions, the nose poke rate decreased, while the proportional distributions of IRTs and postreinforcement pauses shifted toward longer durations as the DRL interval increased. However, most responses occurred before the minimum IRT interval elapsed, suggesting weak temporal control of behavior. Overall, the findings suggest aggression can be a positive reinforcer for nose poke responses in mice on ratio‐ and time‐based reinforcement schedules.
Genuine Worker Participation—An Indispensable Key to Effective Global OHS
Authors: Brown Garrett
Published: September 2009

Working conditions, including workplace safety, in global supply chains of products sold by transnational corporations have only marginally improved over the last 15 years despite the development of hundreds of corporate “codes of conduct,” code monitoring systems, and an elaborate new “corporate social responsibility” industry. The two underlying reasons for the lack of significant change are: 1) a schizophrenic business model which fatally undermines “socially responsible” sourcing programs with unyielding dictates for the lowest possible production costs; and 2) the lack of any meaningful participation by shop-floor workers in plant safety programs. Only when trained, empowered, and active workers are an integral part of workplace safety programs will conditions improve over the long term.
Monitoring Gains and Decentralization
Authors: Theilen Bernd
Published: September 2009

This paper analyzes the delegation of contracting capacity in a moral hazard environment with sequential production in a project which involves a principal and two agents. The agent in charge of the final production can obtain soft information about the other agent's effort choice by investing in monitoring. I investigate the circumstances under which it is optimal for the principal to use a centralized organization in which she designs the contracts with both agents or to use a decentralized organization in which she contracts with only one agent, and delegates the power to contract with the other agent. It is shown that in this setting a decentralized organization can be superior to a centralized organization. This is because the principal is better off under monitoring and the incentives for an agent to invest in monitoring can be higher in a decentralized organization. The circumstances under which this is true are related to monitoring costs and the importance of each agent for production. The results explain the recent application of the design-build method in public procurement.
SOX 404 Reported Internal Control Weaknesses: A Test of COSO Framework Components and Information Technology
Authors: Klamm Bonnie K. , Watson Marcia Weidenmier
Published: September 2009

ABSTRACT: This paper examines internal controls, from both an information technology (IT) and non-IT perspective, in relation to the five components of the Committee of Sponsoring Organization's Internal Control-Integrated Framework (COSO 1992), as well as the achievement of one of COSO's three objectives-reporting reliability. Our sample consists of 490 firms with material weaknesses reported under Sarbanes-Oxley Section 404 during the first year of compliance. We classify the weaknesses by COSO component and as IT-related or non-IT-related. Our results support the interrelationships of the COSO Framework. The results also show that the number of misstated accounts is positively related to the number of weak COSO components (i.e., scope) and certain weak COSO components (i.e., existence). Firms with IT-related weak components report more material weaknesses and misstatements than firms without IT-related weak components, providing evidence on the pervasive negative impact of weak IT controls, especially in control environment, risk assessment, and monitoring.
Bronchial abnormalities found in a consecutive series of 40 brachycephalic dogs
Authors: De Lorenzi Davide , Bertoncello Diana , Drigo Michele
Published: October 2009

Objective—To detect abnormalities of the lower respiratory tract (trachea, principal bronchi, and lobar bronchi) in brachycephalic dogs by use of endoscopy, evaluate the correlation between laryngeal collapse and bronchial abnormalities, and determine whether dogs with bronchial abnormalities have a less favorable postsurgical long-term outcome following correction of brachycephalic syndrome.

Design—Prospective case series study.

Animals—40 client-owned brachycephalic dogs with stertorous breathing and clinical signs of respiratory distress.

Procedures—Brachycephalic dogs anesthetized for pharyngoscopy and laryngoscopy between January 2007 and June 2008 underwent flexible bronchoscopy for systematic evaluation of the principal and lobar bronchi. For dogs that underwent surgical correction of any component of brachycephalic syndrome, owners rated surgical outcome during a follow-up telephone survey. Correlation between laryngeal collapse and bronchial abnormalities and association between bronchial abnormalities and long-term outcome were assessed.

Results—Pugs (n = 20), English Bulldogs (13), and French Bulldogs (7) were affected. A fixed bronchial collapse was recognized in 35 of 40 dogs with a total of 94 bronchial stenoses. Abnormalities were irregularly distributed between hemithoraces; 15 of 94 bronchial abnormalities were detected in the right bronchial system, and 79 of 94 were detected in the left. The left cranial bronchus was the most commonly affected structure, and Pugs were the most severely affected breed. Laryngeal collapse was significantly correlated with severe bronchial collapse; no significant correlation was found between severity of bronchial abnormalities and postsurgical outcome.

Conclusions and Clinical Relevance—Bronchial collapse was a common finding in brachycephalic dogs, and long-term postsurgical outcome was not affected by bronchial stenosis.
Verified Methods for Computing Pareto Sets: General Algorithmic Analysis
Authors: G.-Tóth Boglárka , Kreinovich Vladik
Published: September 2009

Verified Methods for Computing Pareto Sets: General Algorithmic Analysis

In many engineering problems, we face multi-objective optimization, with several objective functionsf1, …,fn. We want to provide the user with the Pareto set—a set of all possible solutionsxwhich cannot be improved in all categories (i.e., for whichfj(x') ≥fj(x) for alljandfj(x') >fj(x) for somejis impossible). The user should be able to select an appropriate trade-off between, say, cost and durability. We extend the general results about (verified) algorithmic computability of maxima locations to show that Pareto sets can also be computed.
Verification Techniques for Sensitivity Analysis and Design of Controllers for Nonlinear Dynamic Systems with Uncertainties
Authors: Rauh Andreas , Minisini Johanna , Hofer Eberhard
Published: September 2009

Verification Techniques for Sensitivity Analysis and Design of Controllers for Nonlinear Dynamic Systems with Uncertainties

Control strategies for nonlinear dynamical systems often make use of special system properties, which are, for example, differential flatness or exact input-output as well as input-to-state linearizability. However, approaches using these properties are unavoidably limited to specific classes of mathematical models. To generalize design procedures and to account for parameter uncertainties as well as modeling errors, an interval arithmetic approach for verified simulation of continuoustime dynamical system models is extended. These extensions are the synthesis, sensitivity analysis, and optimization of open-loop and closed-loop controllers. In addition to the calculation of guaranteed enclosures of the sets of all reachable states, interval arithmetic routines have been developed which verify the controllability and observability of the states of uncertain dynamic systems. Furthermore, they assure asymptotic stability of controlled systems for all possible operating conditions. Based on these results, techniques for trajectory planning can be developed which determine reference signals for linear and nonlinear controllers. For that purpose, limitations of the control variables are taken into account as further constraints. Due to the use of interval techniques, issues of the functionality, robustness, and safety of dynamic systems can be treated in a unified design approach. The presented algorithms are demonstrated for a nonlinear uncertain model of biological wastewater treatment plants.
Uses of New Sensitivity and Dae Solving Methods in SmartMobile for Verified Analysis of Mechanical Systems
Authors: Auer Ekaterina , Luther Wolfram
Published: September 2009

Uses of New Sensitivity and Dae Solving Methods in SmartMobile for Verified Analysis of Mechanical Systems

Software for modeling and simulation (MSS) of mechanical systems helps to reduce production costs for industry. Usually, such software relies on (possibly erroneous) finite precision arithmetic and does not take into account uncertainty in the input data. The program SmartMobile enhances the existing MSS Mobile with verified techniques to provide a guarantee that the obtained results are correct and measure the influence of data uncertainty. In this paper, we outline the main features and functionalities of SmartMobile. In particular, we focus on its use of newly developed methods for sensitivity analysis and DAE solving for several practically relevant mechanical systems.
An Object-Oriented Approach to Simulating Human Gait Motion Based on Motion Tracking
Authors: Tändl Martin , Stark Tobias , Erol Nihat , Löer Franz , Kecskeméthy Andrés
Published: September 2009

An Object-Oriented Approach to Simulating Human Gait Motion Based on Motion Tracking

Accurate bone motion reconstruction from marker tracking is still an open and challenging issue in biomechanics. Presented in this paper is a novel approach to gait motion reconstruction based on kinematical loops and functional skeleton features extracted from segmented Magnetic Resonance Imaging (MRI) data. The method uses an alternative path for concatenating relative motion starting at the feet and closing at the hip joints. From the evaluation of discrepancies between predicted and geometrically identified functional data, such as hip joint centers, a cost function is generated with which the prediction model can be optimized. The method is based on the object-oriented multibody library MOBILE, which has already been successfully applied to the development of industrial virtual design environments. The approach has been implemented in a general gait visualization environment termedMobile Body.
Sir Ernst Gombrich and the Barber from Tuscany
Authors: Lang Karen
Published: September 2009

Sir Ernst Gombrich and the Barber from Tuscany

In the spirit of Sir Ernst Gombrich, this essay uses an anecdote—a chat between Gombrich and a barber from Tuscany—to illustrate a deeper point, namely, how cultural memory, tradition, and a canon give rise to an implied language of culture and cultural value. Gombrich staunchly defended tradition against relativism. By relativism, he meant something like "radical subjectivism." To his mind, subjectivism (in the cultural and social sense of the term) is not only impossible, since meaning is conferred through culture and society, but it is also dangerous (in the cultural and ethical sense of the term), since it denies the existence of shared values. Against consensus on the one hand and radical subjectivism on the other, Gombrich advocated a middle way: criticism and self-criticism to ensure latitude; the search for "truth" to ensure a limited plurality of interpretations.
Cold-War Twins: Mikhail Alpatov's a Universal History of Arts and Ernst Gombrich's the Story of Art
Authors: Azatyan Vardan
Published: September 2009

Cold-War Twins: Mikhail Alpatov's a Universal History of Arts and Ernst Gombrich's the Story of Art

This article deals with the "afterlife" of a methodological disagreement in the Vienna School of Art History between the positions of Alois Riegl and Julius von Schlosser in Mikhail Alpatov's and Ernst Gombrich's art history survey texts published during the Cold War on different sides of the Iron Curtain. Though these surveys are methodological antipodes, the difference itself, I argue, is possible only within the framework of the larger art historical discourse they share. In addition, I will draw on the radical ideological critique of Alpatov's survey inside the Soviet Union and the case of the Stalinist survey meant to replace it, in order to address the ideological commonality between Alpatov's and Gombrich's surveys.
E. H. Gombrich in 1968: Methodological Individualism and the Contradictions of Conservatism
Authors: Hemingway Andrew
Published: September 2009

E. H. Gombrich in 1968: Methodological Individualism and the Contradictions of Conservatism

The commonalities Gombrich affirmed between his own positions on science, politics, and art and those of his friend Karl Popper are key to understanding both his work on the history of style and the conservative fulminations on method he published from the early 1950s onwards. United with Popper by their shared experience of exile from fascism, Gombrich failed to register the amateurish character of Popper's political theory and that his aversion to notions of social determination disabled the historian. Popper's skepticism regarding the ontological status of social collectivities and rejection of the concept of totality reinforced Gombrich's suspicions of holistic analysis and led him to fall back on naturalistic descriptions of individuals acting in a social world glued together by such commonsensical categories as "traditions" and "institutions". In this regard he is representative of the common aversion to sociology of the British intellectual establishment in the early Cold War.
Ten Reasons Why E. H. Gombrich is not Connected to Art History
Authors: Elkins James
Published: September 2009

Ten Reasons Why E. H. Gombrich is not Connected to Art History

This is a speculative essay on the place of E. H. Gombrich in art history. Gombrich is universally known, and still often studied at the undergraduate and graduate levels. He is indispensable for the historiography of the discipline. But at the same time, he is not often cited, and his work is not usually part of the ongoing conversations of the current state of art history or visual studies. This brief essay questions that condition.
Privatization and the Social Value of Water in Africa
Authors: Olutayo Akinpelu , Omobowale Ayokunle , Amzat Jimoh
Published: September 2009

Privatization and the Social Value of Water in Africa

The paper assesses the current clamor and actual privatization of water in Africa. Though this is said to be done in view of wastage and declining access of people to water, this paper submits that the transformation of the social value of water to economic, is rather a continuation of capitalist quest for profit making, which eventually is at the expense of the poor majority.
John Dewey's Ethics: Democracy as Experience
Authors: Madzia Roman
Published: September 2009

John Dewey's Ethics: Democracy as Experience
Histone deacetylase inhibitors valproate and trichostatin A are toxic to neuroblastoma cells and modulate cytochrome P450 1A1, 1B1 and 3A4 expression in these cells
Authors: Hřebačková Jana , Poljaková Jitka , Eckschlager Tomáš , Hraběta Jan , Procházka Pavel , Smutný Svatopluk , Stiborová Marie
Published: September 2009

Histone deacetylase inhibitors valproate and trichostatin A are toxic to neuroblastoma cells and modulate cytochrome P450 1A1, 1B1 and 3A4 expression in these cells

Histone deacetylase inhibitors such as valproic acid (VPA) and trichostatin A (TSA) were shown to exert antitumor activity. Here, the toxicity of both drugs to human neuroblastoma cell lines was investigated using MTT test, and IC50 values for both compounds were determined. Another target of this work was to evaluate the effects of both drugs on expression of cytochrome P450 (CYP) 1A1, 1B1 and 3A4 enzymes, which are known to be expressed in neuroblastoma cells. A malignant subset of neuroblastoma cells, so-called N-type cells (UKF-NB-3 cells) and the more benign S-type neuroblastoma cells (UKF-NB-4 and SK-N-AS cell lines) were studied from both two points of view. VPA and TSA inhibited the growth of neuroblastoma cells in a dose-dependent manner. The IC50values ranging from 1.0 to 2.8 mM and from 69.8 to 129.4 nM were found for VPA and TSA, respectively. Of the neuroblastoma tested here, the N-type UKF-NB-3 cell line was the most sensitive to both drugs. The different effects of VPA and TSA were found on expression of CYP1A1, 1B1 and 3A4 enzymes in individual neuroblastoma cells tested in the study. Protein expression of all these CYP enzymes in the S-type SK-N-AS cell line was not influenced by either of studied drugs. On the contrary, in another S-type cell line, UKF-NB-4, VPA and TSA induced expression of CYP1A1, depressed levels of CYP1B1 and had no effect on expression levels of CYP3A4 enzyme. In the N-type UKF-NB-3 cell line, the expression of CYP1A1 was strongly induced, while that of CYP1B1 depressed by VPA and TSA. VPA also induced the expression of CYP3A4 in this neuroblastoma cell line.
Distal revision of ventriculoperitoneal shunts using a peel-away sheath
Authors: Tubbs R. Shane , Maher Cormac O. , Young Ronald L. , Cohen-Gadol Aaron A.
Published: October 2009

The authors describe a new technique for revision of an occluded distal ventriculoperitoneal shunt catheter that obviates the need for laparotomy or trocar insertion into the peritoneal cavity. The authors review their early experience with 34 patients suffering from a distal ventriculoperitoneal shunt failure and treated with this technique. There were no incidents of intraabdominal injury or wound complications. In 2 patients conversion to a minilaparotomy was required for safe placement of the shunt. Proper peritoneal placement was confirmed with abdominal radiographs in all cases. This technique has been safe and effective and may be considered an alternative to traditional laparotomy or laparoscopic methods.
Specialist Community Nurses: A Critical Analysis of Their Role in the Management of Long-Term Conditions
Authors: McHugh Gretl A. , Horne Maria , Chalmers Karen I. , Luker Karen A.
Published: September 2009

The aim of this narrative review is to identify strategies in use by specialist community and public health nurses in the prevention, care and management of individuals with long-term conditions, specifically chronic obstructive pulmonary disease (COPD) and musculoskeletal disorders. These conditions have been selected as they are highly prevalent; a burden on health services globally and a major public health issue. From a UK policy perspective, specialist community nurses have been placed at the forefront of taking a lead role in the coordination and delivery of more responsive services for individuals with long-term conditions; whether this has been an effective use of skills and resource is questionable. We systematically searched relevant databases between 1999–2009 to identify interventions used by specialist community nurses and critically appraised the studies. This review reports on impact and value of interventions used by specialist community nurses in the prevention and management of COPD and musculoskeletal conditions, and makes recommendations for improving services.
Evaluation of Depigmenting Activity by 8-Hydroxydaidzein in Mouse B16 Melanoma Cells and Human Volunteers
Authors: Tai Sorgan Shou-Ku , Lin Ching-Gong , Wu Mon-Han , Chang Te-Sheng
Published: September 2009

In our previous study, 8-hydroxydaidzein (8-OHDe) was demonstrated to be a potent and unique suicide substrate of mushroom tyrosinase. In this study, the compound was evaluated for in vitro cellular tyrosinase and melanogenesis inhibitory activities in mouse B16 melanoma cells and for in vivo skin-whitening activity in human volunteers. Tyrosinase activity and melanogenesis in the cell culture incubated with 10 µM of 8-OHDe were decreased to 20.1% and 51.8% of control, respectively, while no obvious cytotoxicity was observed in this concentration. In contrast, a standard tyrosinase inhibitor, kojic acid, showed 69.9% and 71.3% of control in cellular tyrosinase and melanogenesis activity, respectively, at a concentration as high as 100 µM. Hence, 8-OHDe exhibited more than an inhibitory effects on melanin production in B16 cells 10-fold stronger than kojic acid. In addition, when a cream containing 4% 8-OHDe was applied to human skin in an in vivo study, significant increases in the dL*-values were observed after three weeks. Moreover, the increase in the dL*-values after 8-week treatment with 4% 8-OHDe (from -0.57 to 1.94) is stronger than those of 2% 8-OHDe treatment (from 0.26 to 0.94) and 2% ascorbic acid-2-glucoside treatment (from 0.07 to 1.54). From the results of the study, it was concluded that 8-OHDe, the potent suicide substrate of mushroom tyrosinase, has depigmenting activities in both mouse melanoma cells and in human volunteers. Thus, the compound has significant potential for use in cosmetics as a skin-whitening ingredient.
Design of Antimicrobially Active Small Amphiphilic Peptide Dendrimers
Authors: Polcyn Piotr , Jurczak Margarita , Rajnisz Aleksandra , Solecka Jolanta , Urbanczyk-Lipkowska Zofia
Published: September 2009

Novel polyfunctional small amphiphilic peptide dendrimers characterized by incorporation of a new core compounds – tris-amino acids or tetrakis-amino alcohols that originated from a series of basic amino acids – were efficiently synthesized. These new core elements yielded molecules with multiple branching and (+5)/(+6) charge at the 1-st dendrimer generation. Dendrimers exhibited significant antimicrobial potency against Gram(+) and Gram(-) strains involving also multiresistant reference strains (S. aureus ATCC 43300 and E. coli ATCC BAA-198). In addition, high activity against fungi from the Candida genus was detected. More charged and more hydrophobic peptide dendrimers expressed hemolytic properties.
Defect Detection in Arc-Welding Processes by Means of the Line-to-Continuum Method and Feature Selection
Authors: Garcia-Allende P. Beatriz , Mirapeix Jesus , Conde Olga  M. , Cobo Adolfo , Lopez-Higuera Jose  M.
Published: September 2009

Plasma optical spectroscopy is widely employed in on-line welding diagnostics. The determination of the plasma electron temperature, which is typically selected as the output monitoring parameter, implies the identification of the atomic emission lines. As a consequence, additional processing stages are required with a direct impact on the real time performance of the technique. The line-to-continuum method is a feasible alternative spectroscopic approach and it is particularly interesting in terms of its computational efficiency. However, the monitoring signal highly depends on the chosen emission line. In this paper, a feature selection methodology is proposed to solve the uncertainty regarding the selection of the optimum spectral band, which allows the employment of the line-to-continuum method for on-line welding diagnostics. Field test results have been conducted to demonstrate the feasibility of the solution.
Systematics of the Carex aquatilis and C. lenticularis lineages: Geographically and ecologically divergent sister clades of Carex section Phacocystis (Cyperaceae)
Authors: Dragon Julie A. , Barrington David S.
Published: September 2009

Carex aquatilis is a highly diverse and geographically widespread member of one of the largest genera of flowering plants, Carex, and is ideally suited for the study of the role of hybridization and niche partitioning in ecological speciation. Phylogenetic analyses of nuclear ITS and ETS 1f and chloroplast psbA‐trnH DNA sequences support the monophyly of a broadly defined Carex aquatilis‐Carex lenticularis lineage, which includes C. aquatilis and C. lenticularis and their allies within section Phacocystis. However, neither taxon is monophyletic as currently circumscribed. The C. aquatilis lineage includes C. aquatilis and four morphologically and molecularly distinct salt‐tolerant maritime taxa with which C. aquatilis s.s. is reported to form stabilized homoploid hybrids. The C. lenticularis lineage includes a paraphyletic C. lenticularis and seven allied species from both the New and Old World. The data provided here allow recognition of four species within the North American endemic C. lenticularis and suggest a neotropical origin for the C. lenticularis lineage with subsequent radiation and divergence through northwestern North America to Asia and via northeastern North America to Europe and southern South America. Evolutionary rate analyses indicate an origin for the C. aquatilis‐C. lenticularis group around 1.89 million years ago during the early Pleistocene.
Genetic variation in the allotetraploid Dryopteris corleyi (Dryopteridaceae) and its diploid parental species in the Iberian Peninsula
Authors: Jiménez Ares , Quintanilla Luis G. , Pajarón Santiago , Pangua Emilia
Published: September 2009

Studies on genetic diversity help us to unveil the evolutionary processes of species and populations and can explain several traits of diploid–polyploid complexes such as their distributions, their breeding systems, and the origin of polyploids. We examined the allozyme variation of Dryopteris aemula and D. oreades, diploid ferns with highly fragmented habitats, and the allotetraploid D. corleyi to (1) analyze the putative relationship between both diploids and the tetraploid, (2) compare the levels of genetic variation among species and determine their causes, and (3) assess the breeding system of these taxa. The allozymic pattern of D. corleyi confirms that it derived from D. aemula and D. oreades. The lack of genetic diversity in D. aemula, a species of lowland habitats, may be due to genetic drift associated with the contraction of populations in the last glaciation. By contrast, the alpine D. oreades had moderate intrapopulation genetic variation, which may derive from the expansion of populations during the last glaciation. In the latter species, low interpopulational variation suggested effective gene flow (spore exchange), and genotype frequencies in Hardy–Weinberg equilibrium indicated cross‐fertilization of gametophytes. Evolutionary history appears to be an essential element in the interpretation of genetic variation of highly fragmented populations.