bluuebunny/crossref_metadata_2025 huggingface dataset:
An Energy-efficient Rate Adaptive Media Access Protocol (RA-MAC) for Long-lived Sensor Networks
Authors: Hu Wen , Chen Quanjun , Corke Peter , O’Rourke Damien
Published: June 2010

We introduce an energy-efficient Rate Adaptive Media Access Control (RA-MAC) algorithm for long-lived Wireless Sensor Networks (WSNs). Previous research shows that the dynamic and lossy nature of wireless communications is one of the major challenges to reliable data delivery in WSNs. RA-MAC achieves high link reliability in such situations by dynamically trading off data rate for channel gain. The extra gain that can be achieved reduces the packet loss rate which contributes to reduced energy expenditure through a reduced numbers of retransmissions. We achieve this at the expense of raw bit rate which generally far exceeds the application’s link requirement. To minimize communication energy consumption, RA-MAC selects the optimal data rate based on the estimated link quality at each data rate and an analytical model of the energy consumption. Our model shows how the selected data rate depends on different channel conditions in order to minimize energy consumption. We have implemented RA-MAC in TinyOS for an off-the-shelf sensor platform (the TinyNode) on top of a state-of-the-art WSN Media Access Control Protocol, SCP-MAC, and evaluated its performance by comparing our implementation with the original SCP-MAC using both simulation and experiment.
Non-Revenue Water: Financial Model for Optimal Management in Developing Countries
Authors: Wyatt Alan
Published: June 2010

Non-revenue water (NRW) includes physical losses (pipe leaks) and commercial losses (illegal connections, unmetered public use, meter error, unbilled metered water, and water for which payment is not collected). NRW levels are high in many developing countries, and they can be expensive to reduce. Members of the International Water Association (IWA) Water Loss Task Force developed the Economic Level of Leakage (ELL), which outlines the optimal level of physical losses based on engineering inputs. However, the ELL approach is less useful in developing countries than in developed countries, as it ignores commercial losses, the annualized cost of water supply capacity expansion, and situations in which production capacity does not meet demand. This report presents a financial model that addresses the limitations noted above and provides acceptably accurate values of optimal, steady-state NRW without the need for large data collection efforts. The model uses an NRW framework adapted from the IWA Water Balance and the Burst and Background Estimates (BABE) and Econoleak methodologies. The report presents specific results for 59 utilities in 27 countries in Asia, Africa, and Eastern Europe; these include optimal NRW, optimal physical losses, optimal commercial losses, optimal meter replacement frequencies, optimal leak detection survey frequencies, actual losses, and impacts on utility revenue and water supply coverage. This model allows utility managers and regulators to establish NRW targets and to optimally allocate resources to NRW management. Ultimately, use of the model will help save water, increase utility revenues, expand coverage, and reduce health and economic impacts.
Relationship Between Rheumatoid Factor Isotypes and IgG Anti-Cyclic Citrullinated Peptide Antibodies
Authors: JASKOWSKI TROY D. , HILL HARRY R. , RUSSO KATHERINE L. , LAKOS GABRIELLA , SZEKANECZ ZOLTAN , TEODORESCU MARIUS
Published: June 2010

Objective.

To validate in a general patient population (GPP) the clinical value of measuring rheumatoid factor (RF) isotypes in relationship to IgG anti-cyclic citrullinated peptide (CCP) antibodies (CCP2 and CCP3).

Methods.

Serum samples were obtained as follows: 1021 GPP, for whom RF was ordered for diagnosis, 137 with rheumatoid arthritis (RA), 100 healthy blood donors (HBD), and 50 with systemic lupus erythematosus. Turbidimetry and ELISA were utilized for RF screening, and individual RF isotypes and IgG anti-CCP antibodies were measured by ELISA; RF IgG was measured after pepsin digestion.

Results.

We validated the generally accepted 90%–98% positive predictive value (PPV) and about 68% sensitivity of the anti-CCP2 test on our diagnosed cohorts as 96% (95% CI 89–99) and 65% (95% CI 56–73), respectively. The 282 RF IgM+ specimens identified in the GPP were subdivided into 3 subsets: (1) 83 as RF IgM+ IgG+ IgA+ with 63% (95% CI 51–73) anti-CCP2+ (i.e., sensitivity similar to the RA cohort); (2) 50 as RF IgM+ IgG− IgA+ with significantly fewer anti-CCP2+ (22%; 95% CI 12–36); and (3) about half as IgM+ IgG− IgA− with just 3% (95% CI 1–8) anti-CCP2+, i.e., not significantly different from the 1% (95% CI 0–5) in HBD. Thus, the chance for a specimen in the GPP to be anti-CCP2+ (i.e., to come from an RA patient) was increased by 7- and 21-fold, respectively, by identifying RF IgA and IgG in addition to IgM. About one-third of anti-CCP− RA patients in our cohort were RF IgM+ IgG+ IgA+, reflected as 3.4% in the anti-CCP2− GPP. The agreement between anti-CCP2 and anti-CCP3 was significantly higher for RF+ RA and GPP patients, 86% (95% CI 78–93) and 83% (95% CI 73–91), respectively, than for the RF− RA (27%; 95% CI 6–61), RF− GPP (4%; 95% CI 0–19), and non-RA controls. Anti-CCP2 but not anti-CCP3 significantly distinguished the HBD from the GPP (95% CI).

Conclusion.

Measurement of the 3 isotypes of RF may increase by 7- to 21-fold the chance of making the serologic diagnosis of RA; a testing algorithm is proposed. The anti-CCP antibody response appears significantly less peptide-specific in the presence of IgM RF than in its absence.
L'affaire Philippe Sauveur : Proust en dialogue avec un roman manuscrit de Ramon Fernandez
Authors: Fraisse Luc
Published: June 2010

Les quelques lettres qui nous sont conservées, échangées entre Proust et Ramon Fernandez (1894-1944), mentionnaient un roman de Fernandez en cours de rédaction, intitulé Philippe Sauveur et demeuré inédit. Une grande partie des manuscrits en ont été retrouvés par Dominique Fernandez : l’œuvre se présente en trois versions, qui sont prises en compte ici, Proust ayant eu entre les mains les deux premières. Il s’agit d’un roman sur l’inversion. En 1917-1918, alors que le romancier de la Recherche met la dernière main aux Jeunes filles en fleurs et poursuit l’élaboration de Sodome et Gomorrhe et de l’épisode d’Albertine, divers parallèles invitent à penser que Proust s’inspire de scènes lues chez Fernandez, à son tour influencé par Du côté de chez Swann dans les premières versions, puis par la parution de Sodome et Gomorrhe dans la dernière, que Proust n’a pas connue. Car après la mort de Proust, Fernandez entretiendra pendant vingt ans encore une discussion avec le roman de la Recherche  ; la consultation des versions manuscrites de son propre roman permet d’apercevoir que se règle, dans ces riches débats sur les techniques de mise en scène du personnage inverti, l’abandon de Philippe Sauveur . L’auteur de Sodome et Gomorrhe se trouve, à la faveur de cette confrontation de manuscrit à manuscrit, soumis à une critique philosophique et structurale dont il faut noter la modernité.
Le langage de la phénoménologie : analogie ou citation ?
Authors: Grondin Vincent
Published: June 2010

S ’ il faut en croire plusieurs wittgensteiniens, l ’œ uvre de Wittgenstein représenterait de facto une réfutation de l ’ idéalisme. Selon cette grille de lecture, le retour au langage ordinaire impliquerait un rejet implicite de l ’ idéalisme. Puisque Husserl prétend lui-même que la phénoménologie est une forme d ’ idéalisme transcendantal, on pourrait être tenté d ’ insister sur le gouffre philosophique qui sépare ces deux auteurs, auteurs qui s ’ inscrivent par ailleurs dans deux traditions très différentes. En revenant sur le désaccord entre Fink et Husserl relativement à la question du langage ordinaire, je voudrais déconstruire cette opposition en mettant en relief le fait que l ’ idéalisme husserlien ne s ’ oppose pas frontalement à la grammaire du langage ordinaire.
Du côté de chez Saint-Simon: question raciale, question sociale et question religieuse
Authors: Régnier Philippe
Published: June 2010

Résumé L’examen des théories de la race développées par Saint-Simon et par ses divers héritiers idéologiques (en particulier Michel Chevalier, Gustave d’Eichthal, Victor Courtet et Pierre Leroux) montre leur conviction précoce et commune que la prise en compte des différences à l’intérieur de l’humanité constitue un enjeu décisif du changement vers l’égalité et l’association universelles. Tout en explorant, pour certains, l’hypothèse naturaliste, les saint-simoniens s’accordent à mettre l’accent sur les dimensions sociale et religieuse de l’identité ethnique. Le préjugé de la supériorité de la « race européenne» ne les retient pas, au contraire, de conclure à une politique de métissage.
Le Paris de Tardi : un xixe siècle éternel ?
Authors: Bernard Jean-Pierre A.
Published: June 2010

Résumé Les quatre volumes du Cri du peuple de Tardi mettent en scène le Paris de la Commune, avec un certain nombre d’épisodes historiques, de la Proclamation du 18 mars à la mort pendant la Semaine sanglante, fin mai. Moments d’une histoire violente inscrits dans un décor de pierre, fidèle jusqu’à l’obsession photographique au Paris réel. Aussi, roman populaire, mélodrame même, qui viennent battre sur la trame tragique des événements. C’est un album sur la Commune, un album sur Paris – Paris daté mais aussi Paris éternel, cette éternité du xix e  siècle qui paraît si cher à Tardi.
De Goya à Hemingway : visions tauromachiques
Authors: Bottois Ozvan
Published: June 2010

Résumé Le peintre espagnol Francisco de Goya y Lucientes et l’écrivain américain Ernest Hemingway comptent sans doute parmi les plus célèbres aficionados . Le premier a marqué l’histoire de la représentation artistique de la tauromachie, notamment avec sa série de gravures intitulée Tauromaquia , éditée en 1816. Le second est l’auteur d’un ouvrage paru en 1932, Mort dans l’après-midi , indispensable à quiconque s’intéresse aux courses de taureaux. Cette courte étude souhaite montrer comment, malgré une différence d’époque et de support, les deux hommes tendent à proposer une approche analogue de la corrida, tant sur le plan esthétique qu’éthique. Elle vise également à appréhender la façon dont près d’un siècle plus tard, Ernest Hemingway a pu se retrouver et puiser dans l’héritage laissé par Goya, faisant ainsi écho au peintre dans sa conception et sa représentation de la tauromachie.
Cultivating the Value of Networked Individuals
Authors: Richter Wolf R. , Bray David A. , Dutton William H.
Published: June 2010

The Internet and related digital networking platforms facilitate searches for information and the sharing of information and expertise among individuals. In recent years, these behaviours evolved from focusing on information retrieval and sharing to include facilitation and coordination of collaborative problem-solving efforts and distributed co-creation of services and products. Such collaborations, supported by digital networks, often extend beyond the traditional boundaries of organizations and institutions, the social networks of small groups, the subjects of specific disciplines, and the geographic borders of nations. Consequently, they raise concerns over how to best manage networked individuals and realize the potential utility of their activities. This chapter builds on the findings of a series of case studies designed to explore such questions. From the results of these case studies the authors propose a framework for categorizing ‘Collaborative Network Organizations’ (CNOs); one that suggests that value emerges as a result of cultivating particular kinds of relationships and activities within these networks. The authors employ the term ‘cultivation’, instead of management, as the case studies indicated that such efforts often fail if managed too precisely or too restrictively in a “top-down” fashion. Instead, the provision of greater latitude and “bottom-up” autonomy to the individuals involved characterized the more successful CNOs we studied. In addition, the success of CNOs depended on how such efforts reconfigured information and communication flows in ways that supported distributed sharing, generation, or co-creation of content within a wide variety of collaborative contexts, ranging from the conduct of scientific research to problem-solving in business and everyday life. Directly attempting to manage or control CNOs can undermine these networks, whereas indirectly influencing and cultivating desired behaviours and activities can encourage the expansion of productive networking. The authors offer this theoretical framework as a means for better capturing the mechanisms governing collaborative behaviour.
It Was Only Natural
Authors: Hendrickson Elizabeth Meyers
Published: June 2010

This chapter describes the cross-disciplinary conceptual frameworks used to examine a popular American entertainment website that employs a virtual newsroom utilizing instant messaging as its primary means of communication. This computer-mediated communication reconfigures the standard place-based newsroom arrangements and significantly influences the group’s organizational dynamics and culture. Because of the distinctive content and unconventional organizational structure of this site, no single theoretical perspective can be applied to its organizational context and content. Therefore a combination of organization theory (Schein, 2004), and newsroom sociology theoretical frameworks articulates an emerging dynamic represented by such a medium’s evolution from hierarchical to networked organization. This chapter exemplifies the potential for new media researchers to adopt a cross-disciplinary approach to their analysis. As old models for understanding media cease to support the complex structures of new organizations we must look to other frameworks for additional guidance.
Informing Traces
Authors: McKenzie Pamela J.
Published: June 2010

The concept of “traces” is useful for understanding the collaborative practices of informing. Readers of documents leave traces of their use, and institutional talk embeds traces of collaborative work, including work done and elsewhere and at other times. This chapter employs a multifaceted qualitative strategy of analytic bracketing to analyze traces in midwives’ and clients’ discussions of clinical results. Results are used to identify and evaluate trends in relation to the current case or to universal norms. Conflicting forms of evidence may need to be negotiated. Barriers may arise when results or sources are inadequate or unavailable. Midwives and women manage these barriers by flexibly assigning the role of information provider in official and unofficial ways. The analysis of traces provides insight into the hows and whats of collaborative work and reveals it to be a complex set of practices that go well beyond the immediately visible contributions of others.
Collaboration as Co-Constructed Discourse
Authors: Foster Jonathan
Published: June 2010

This chapter presents a coding guide for the analysis of peer talk during educational information seeking. The guide is an outcome of a structuring content analysis of learners’ dialogues as they seek, evaluate, and use information on a collaborative basis. The analysis is informed by a language-based theory of learning and the sequential organization of spoken discourse. The generic steps of a structuring content analysis are described first; before each step, sequence, exchange, and move type identified in the dialogues are described. Illustrative examples of each unit and type of talk are provided, so as to aid in the precise and reliable assignment of the categories and codes in further studies. The chapter concludes with implications of the coding guide, and the broader study of which it is a part, for research in educational information seeking.
Well-posedness of a parabolic moving-boundary problem in the setting of Wasserstein gradient ﬂows
Authors: Portegies Jacobus W. , Peletier Mark A.
Published: June 2010

We develop a gradient-ﬂow framework based on the Wasserstein metric for a parabolic moving boundary problem that models crystal dissolution and precipitation. In doing so we derive a new weak formulation for this moving-boundary problem and we show that this formulation is well posed. In addition, we develop a new uniqueness technique based on the framework of gradient ﬂows with respect to the Wasserstein metric. With this uniqueness technique, the Wasserstein framework becomes a complete well-posedness setting for this parabolic moving-boundary problem.
Automorphic realization of residual Galois representations
Authors: Guralnick Robert M. , Harris Michael , Katz Nicholas M.
Published: June 2010

We show that it is possible in rather general situations to obtain a ﬁnite-dimensional modular representation
ρ
of the Galois group of a number ﬁeld
F
as a constituent of one of the modular Galois representations attached to automorphic representations of a general linear group over
F
, provided one works “potentially.” The proof is based on a close study of the monodromy of the Dwork family of Calabi–Yau hypersurfaces; this in turn makes use of properties of rigid local systems and the classiﬁcation of irreducible subgroups of ﬁnite classical groups with certain sorts of generators.
The Ore conjecture
Authors: Liebeck Martin W. , O'Brien Eamonn A. , Shalev Aner , Tiep Pham Huu
Published: June 2010

The Ore conjecture, posed in 1951, states that every element of every finite non-abelian simple group is a commutator. Despite considerable effort, it remained open for various infinite families of simple groups. In this paper we develop new strategies, combining character-theoretic methods with other ingredients, and use them to establish the conjecture.
Household-Based Sero-Epidemiologic Survey after a Yellow Fever Epidemic, Sudan, 2005
Authors: Farnon Eileen C. , Hannah Gould L. , Griffith Kevin S. , Osman Magdi S. , Kholy Amgad El , Brair Maria-Emanuela , Panella Amanda J. , Kosoy Olga , Laven Janeen J. , Godsey Marvin S. , Perea William , Hayes Edward B.
Published: June 2010

From September through early December 2005, an outbreak of yellow fever (YF) occurred in South Kordofan, Sudan, resulting in a mass YF vaccination campaign. In late December 2005, we conducted a serosurvey to assess YF vaccine coverage and to better define the epidemiology of the outbreak in an index village. Of 552 persons enrolled, 95% reported recent YF vaccination, and 25% reported febrile illness during the outbreak period: 13% reported YF-like illness, 4% reported severe YF-like illness, and 12% reported chikungunya-like illness. Of 87 persons who provided blood samples, all had positive YF serologic results, including three who had never been vaccinated. There was also serologic evidence of recent or prior chikungunya virus, dengue virus, West Nile virus, and Sindbis virus infections. These results indicate that YF virus and chikungunya virus contributed to the outbreak. The high prevalence of YF antibody among vaccinees indicates that vaccination was effectively implemented in this remotely located population.
Temporal Connections between Culex tarsalis Abundance and Transmission of Western Equine Encephalomyelitis Virus in California
Authors: Barker Christopher M. , Johnson Wesley O. , Eldridge Bruce F. , Park Bborie K. , Melton Forrest , Reisen William K.
Published: June 2010

Definition of targets for vector control requires an understanding of the relationship between vector abundance and the intensity of arbovirus transmission. Using an extensive surveillance dataset with observations from sentinel chicken flocks and mosquito traps paired in time and space, hierarchical autoregressive logistic regression models were developed to predict the probability of seroconversion in chickens for western equine encephalomyelitis virus (WEEV) based on the relative abundance of the principal vector, Culex tarsalis. After adjustments for confounders, the abundance of Cx. tarsalis 29–42 d before the date of chicken sampling was credibly associated with the risk of WEEV transmission in both the Central and Coachella Valleys, and a doubling of relative Cx. tarsalis abundance was associated with a 58% increase in the odds of seroconversion. The critical time windows identified in our study highlight the need for surveillance of vector populations and forecasting models to guide proactive vector control measures before the detection of transmission to sentinel chickens.
High Frequency of Diarrheagenic Escherichia coli in Human Immunodeficiency Virus (HIV) Patients with and without Diarrhea in Lima, Perú
Authors: Garcia Coralith , Chincha Omayra , Leon Mey , Iglesias David , Barletta Francesca , Mercado Erik , Ochoa Theresa
Published: June 2010

Diarrhea is still a prevalent health issue in HIV patients. Our objective was to characterize the different diarrheagenic E. coli (DEC) groups in stools from adult HIV patients. Cross sectional study: We enrolled HIV-positive and -negative patients with and without diarrhea from a tertiary-care center of Lima, Peru. Clinical data was recorded and a stool sample per patient was cultured. Multiplex PCR was used to detect different DECs. One hundred eighty-four participants were enrolled. The frequency of having at least one DEC was more common in HIV-positive than HIV-negative patients with diarrhea (42% versus 20%, P < 0.05). The enterotoxigenic E. coli (ETEC) was the most common DEC in patients with diarrhea, 13% in HIV patients. The diffusely adherent E. coli (DAEC) was only present in HIV positive patients with diarrhea (10.1%). Different types of DEC are frequent in stools from HIV-positive patients.
Adherence to 7-Day Primaquine Treatment for the Radical Cure of P. vivax in the Peruvian Amazon
Authors: Grietens Koen Peeters , Soto Veronica , Erhart Annette , Ribera Joan Muela , Toomer Elizabeth , Tenorio Alex , Montalvo Tanilu Grande , Rodriguez Hugo , Cuentas Alejandro Llanos , D'Alessandro Umberto , Gamboa Dionicia
Published: June 2010

Despite being free of charge, treatment adherence to 7-day primaquine for the radical cure of Plasmodium vivax was estimated at 62.2% among patients along the Iquitos-Nauta road in the Peruvian Amazon. The principal reason for non-adherence was the perceived adverse effects related to local humoral illness conceptions that hold that malaria produces a hot state of body, which is further aggravated by the characteristically hot medical treatment. Notably, patients were willing to adhere to the first 3 days of treatment during which symptoms are most apparent and include the characteristic chills. Nevertheless, as symptoms abate, the perceived aggravating characteristics of the medication outweigh the perceived advantages of treatment adherence. Improving community awareness about the role of primaquine to prevent further malaria transmission and fostering a realistic system of direct observed treatment intake, organized at community level, can be expected to improve adherence to the radical cure of P. vivax in this area.
Elimination of Malaria Risk through Integrated Combination Strategies in a Tropical Military Training Island
Authors: Lee Vernon J. , Ow Samuel , Heah Harold , Tan Meng Yaw , Lam Patrick , Ng Lee-Ching , Lam-Phua Sai Gek , Imran Abdul Qadir , Seet Benjamin
Published: June 2010

On the military training facility of Tekong Island, Singapore, a comprehensive vector-borne disease control program was started in end-2006 to reduce mosquito populations and negate the need for anti-malaria chemoprophylaxis. The program was based on 1) preventing importation of malaria through screening of visitors, 2) preventing human-to-mosquito transmission through early case detection and mosquito control, 3) preventing mosquito-to-human transmission through personal protection, and 4) contingency plans. Systematic environmental works were performed to reduce breeding sites, and insecticide use targeted both adult mosquitoes and larvae. Mosquito populations declined from 103 mosquitoes per sampling site in January 2007 to 6 per site by March 2007 (P < 0.001). The proportion of positive ovitraps declined from 93% in January 2007–2% in March 2007 (P < 0.001). There were no malaria cases on the island despite chemoprophylaxis termination, showing that comprehensive combination vector-control strategies were effective in reducing the risk of malaria.
Reibergram of Intrathecal Synthesis of C4 in Patients with Eosinophilic Meningitis Caused by Angiostrongylus cantonensis
Authors: Padilla-Docal Bárbara , Dorta-Contreras Alberto Juan , Bu-Coifiu-Fanego Raisa , Rodríguez-Rey Alexis , Gutiérrez-Hernández Juan Carlos , de Paula-Almeida Susana Olga
Published: June 2010

Angiostrongylus cantonensis produces eosinophilic meningitis in humans and is endemic in Thailand, Taiwan, China, and the Caribbean region. During infection with this parasite, it is important to know if the complement system may be activated by the classical or lectin pathway. Cerebrospinal fluid and serum samples from 20 patients with meningitic angiostrongyliasis were used to quantify C4 levels and albumin. Results were plotted on a C4 CSF/serum quotient diagram or Reibergram. Twelve patients showed intrathecal synthesis of C4. Antibody-dependent complement cytotoxicity should be considered as a possible mechanism that destroys third-stage larvae of this helminth in cerebrospinal fluid of affected patients.
Direct Genotypic Characterization of Toxoplasma gondii Strains Associated with Congenital Toxoplasmosis in Tunisia (North Africa)
Authors: Boughattas Sonia , Ben-Abdallah Rym , Siala Emna , Souissi Olfa , Aoun Karim , Bouratbine Aïda
Published: June 2010

Here, we determined the Toxoplasma gondii genotype in amniotic fluid, placenta, and cerebrospinal fluid samples from 14 congenital toxoplasmosis cases in Tunisia, North Africa. Direct genotypic characterization of T. gondii strains was performed by polymerase chain reaction (PCR) amplification of six genetic markers (3'SAG2, 5' SAG2, SAG3, BTUB, GRA6, and APICO) and thereafter, was analyzed by restriction fragment-length polymorphism (RFLP). Samples were sequenced to resolve strain type whenever there were unclear enzyme digestion results. Multilocus analysis revealed that only one specimen harbored the type I allele in all studied loci, whereas the 13 others gave mixed genotype results with different alleles at different markers. Seven specimens produced RFLP profile of the recombinant strains I/III, and three produced a profile of I/II recombinant strains. The last three specimens produced complex digestion patterns. In these cases, sequence analysis revealed double peaks at known polymorphic sites, indicating the presence of multiple alleles.
Optimal Survey Designs for Targeting Chemotherapy Against Soil-Transmitted Helminths: Effect of Spatial Heterogeneity and Cost-Efficiency of Sampling
Authors: Sturrock Hugh J. W. , Gething Peter W. , Clements Archie C. A. , Brooker Simon
Published: June 2010

Implementation of helminth control programs requires information on the distribution and prevalence of infection to target mass treatment to areas of greatest need. In the absence of data, the question of how many schools/communities should be surveyed depends on the spatial heterogeneity of infection and the cost efficiency of surveys. We used geostatistical techniques to quantify the spatial heterogeneity of soil-transmitted helminths in multiple settings in eastern Africa, and using the example of Kenya, conducted conditional simulation to explore the implications of alternative sampling strategies in identifying districts requiring mass treatment. Cost analysis is included in the simulations using data from actual field surveys and control programs. The analysis suggests that sampling four or five schools in each district provides a cost-efficient strategy in identifying districts requiring mass treatment, and that efficiency of sampling was relatively insensitive to the number of children sampled per school.
Identification of Bartonella Infections in Febrile Human Patients from Thailand and Their Potential Animal Reservoirs
Authors: Kosoy Michael , Bai Ying , Sheff Kelly , Morway Christina , Baggett Henry , Maloney Susan A. , Boonmar Sumalee , Bhengsri Saithip , Dowell Scott F. , Sitdhirasdr Anussorn , Lerdthusnee Kriangkrai , Richardson Jason , Peruski Leonard F.
Published: June 2010

To determine the role of Bartonella species as causes of acute febrile illness in humans from Thailand, we used a novel strategy of co-cultivation of blood with eukaryotic cells and subsequent phylogenetic analysis of Bartonella-specific DNA products. Bartonella species were identified in 14 blood clots from febrile patients. Sequence analysis showed that more than one-half of the genotypes identified in human patients were similar or identical to homologous sequences identified in rodents from Asia and were closely related to B. elizabethae, B. rattimassiliensis, and B. tribocorum. The remaining genotypes belonged to B. henselae, B. vinsonii, and B. tamiae. Among the positive febrile patients, animal exposure was common: 36% reported owning either dogs or cats and 71% reported rat exposure during the 2 weeks before illness onset. The findings suggest that rodents are likely reservoirs for a substantial portion of cases of human Bartonella infections in Thailand.
Larval fish feeding and turbulence: A case for the downside
Authors: MacKenzie Brian R. , KiØrboe Thomas
Published: June 2010

Theory states that small‐scale turbulence decreases pursuit success of planktonic predators by advecting the encountered prey from the reactive zone of the predator during the pursuit event. We tested the quantitative predictions of a previously published model describing this phenomenon in larval cod by videorecording particle motion and feeding behavior of larval cod (8.7–12.3 mm) preying on copepods in a laboratory tank. Fluid motion shared characteristics with that in the ocean, i.e., intermittent, logarithmically distributed, average particle‐particle velocity difference proportional to separation distance1/3. Estimated bulk dissipation rates were 0–2 × 10−8 m2 s−3 and similar to those commonly experienced by larval cod in nature (e.g., located at 30 m during winds of ca.7 m s‐1 ). Owing to the intermittent nature of turbulence, we related individual predation events to local, instantaneous relative velocities instead of bulk averages. Pursuit success decreased significantly with relative velocity and the observations approximated the predicted effect of turbulence on pursuit success. Nonlinear and counteracting effects of turbulence on pursuit success and encounter may partly explain the contradictory observations of how turbulence affects larval fish feeding, growth, and survival in the sea.
Latitudinal patterns in the size distribution and seasonal dynamics of new world, freshwater cladocerans
Authors: Gillooly James F. , Dodson Stanley I.
Published: June 2010

Analysis of zooplankton communities in over 1,100 water bodies spanning the Western Hemisphere (77°S, 81°N latitude) revealed latitudinal patterns in cladoceran body size and Daphnia seasonal dynamics. The mean body length of cladoceran species occurring at different latitudinal intervals was greatest in north temperate regions, declining in size toward the poles and equator. Thus, mean cladoceran size was greatest in regions where the mean annual surface temperatures of lakes ranged from 6 to 8°C in both the Northern and Southern Hemispheres. The date of maximum Daphnia abundance and the period of minimum Daphnia abundance in lakes of North America was positively, linearly related to the latitudinal position of the lakes. The date of maximum abundance increased with latitude such that Daphnia peaked during nearly all months of the year depending on latitude, but usually within the same, narrow temperature range (15–20°C). The period of minimum Daphnia abundance decreased linearly with latitude such that abundance generally was minimal when water temperatures exceeded 20°C.
Ammonium excretion by Antarctic krill Euphausia superba at South Georgia
Authors: Atkinson Angus , Whitehouse Michael J.
Published: June 2010

Excretion by Antarctic krill Euphausia superba (hereafter “krill”) is measured typically in small containers of filtered seawater for 12–24 h, which may cause a reduction of swimming, feeding, and metabolism. If the maximum published excretion rates are realistic, krill would be a major source of regenerated nitrogen in the South Georgia area because of their high biomass there. Because literature values are variable, depending on season, feeding history and the experimental set‐up, our aim was to measure both a mean and an upper value of krill excretion rate at South Georgia. Experiments were on juvenile krill during October–November 1997 and January 1998. Freshly caught animals excreted 1.6–2.8 nmol ammonium mg−1 dry mass h−1; within the fivefold range of summer literature values for equivalent‐sized krill. Maximum rates were determined on acclimated krill in large containers during alternating 1‐d periods with and without food. During the feeding periods in saturating food concentrations, the mean daily ration was ~32% of body carbon d−1 and excretion was 210% (October–November) and 280% (January) of the values for freshly caught krill. This equates to a maximum loss of ~2% of body nitrogen d−1. Excretion rates decreased during the 1‐d periods without food, and rates during the feeding periods were ~30% higher than in those without food. This suggests that the lack of feeding in traditional experiments leads to roughly 30% underestimates of excretion rate. These results help to set some limits on ammonium production rates of South Georgia krill over regional scales. Our calculations suggest that the role of krill in this varies between habitats to the west of the island (insignificant) and those in the east (significant).
Herbivory and irradiance shape periphytic architecture in a Swiss alpine stream
Authors: Wellnitz Todd A. , Ward J.V.
Published: June 2010

The effects of herbivory and light on epilithic periphyton from Minor Creek (2,200 m above sea level), a Swiss alpine stream, were examined by manipulating light intensity and the densities of two abundant grazers in stream‐side channels. We hypothesized that the high light intensities in Minor Creek (exceeding 2,000 μmol m−2 s−1 on the stream bed) would cause photoinhibiton and thus regulate algal composition and biomass accrual. After 18 d, full sunlight had negative effects on all measures of periphytic abundance in streamside channels. A five‐level light gradient experiment in Minor Creek corroborated these findings: full sunlight suppressed periphytic accumulation.

To test the interactive effects of grazing and light, we used two herbivorous insects with distinctly different feeding structures. Ecdyonurus sp. (Heptageniidae) possesses brushing mouthparts; Drusus lateralis (Limnephilidae) has scraping mandibles. In accordance with a conceptual model that predicts algal physiognomy and herbivore feeding mode regulate algal susceptibility to grazing, we hypothesized that Ecdyonurus would primarily reduce physiognomies composing the periphytic overstory (e.g., stalked and filamentous algae), whereas Drusus would have greater access to understory physiognomies (e.g., prostrate forms). In addition, we hypothesized that tall physiognomies would be less abundant under full sunlight due to the exposure of the periphytic mat to photoinhibiting irradiance. Thus, we expected Ecdyonurus to have a smaller effect on periphyton at high light intensities.

Light in channels did not directly modify grazing effects; however, the data suggest light intensity altered periphytic susceptibility to grazing. Channels receiving full sunlight had less periphyton, yet grazer weights did not differ between light treatments despite the fact that weight gain for each grazer was negatively correlated with conspecific biomass, implicating competition for limited periphytic food. Algal responses were most pronounced under grazing by Ecdyonurus, which was associated with decreases in the abundance of six of the seven algal physiognomies. Contrary to model predictions, Ecdyonurus reduced low‐lying as well as overstory physiognomies. Drusus, by contrast, was associated with reductions in only four physiognomies. Results from this study suggest that understanding periphytic community responses to grazing will require more sophisticated models of periphytic structure.
Light absorption and utilization by colonies of the congeneric hermatypic corals Montastraea faveolata and Montastraea cavernosa
Authors: Lesser Michael P.Lesser , Mazel Charles , Phinney David , Yentsch Charles S.
Published: June 2010

The congeneric species Montastraea faveolata and Montastraea cavernosa are important hermatypic corals on reefs throughout the Bahamas, Caribbean, and the Florida reef tract that have overlapping bathymetric distributions. However, these congeners differ in their respective abundance at similar depths. The underlying mechanism for these patterns may partly be because of their relative dependence on photoautotrophy versus heterotrophy. The dependence of these two corals on photoautotrophy was examined quantifying the optical properties and productivity of these two species of corals at two different depths in the Dry Tortugas. Maximum surface irradiances in the Dry Tortugas during this study varied from 1,900 to 2,100 μmol quanta m‐2 s‐1. Spectral attenuation coefficients calculated from the 1995 and 1996 irradiance data differed by as little as 10% within the visible wavelengths (photosynthetically active radiation [PAR], 400–700 nm), suggesting year‐to‐year similarities in the optical prop‐erties of the overlying water column. Underwater irradiances of PAR were ∼400 μmol quanta m−2 s−1 and 25 μmol quanta m‐2 s‐1 at 10 m and 18 m, respectively. Significantly lower rates of maximum photosynthesis were observed for samples of M. cavernosa compared with M. faveolata at 10 m and 18 m. For samples of M. faveolata from both depths, the mean chlorophyll‐specific absorption (a*) across all PAR wavelengths was greater than that of M. cavernosa. When spectrally corrected for the underwater light field and used to calculate the minimum quantum requirements (1/_m) of these corals at each depth, we observed that M. faveolata always had higher 1/_m than M. cavernosa (50 versus 18 quanta O2−1 and 39 versus 15 quanta O2‐1 at 10 m and 18 m, respectively.) M. cavernosa, with its greater pigment concentrations and lower a*, exhibits a significant package effect that results in a smaller functional optical cross section and lower maximum photosynthetic capacities, whereas M. faveolata at the same depths, despite the greater minimum quantum requirements, has a larger functional optical cross section and enhanced absorption of available visible radiation, resulting in a greater maximum photosynthetic capacity. Based on polyp size, corallite structure, and surface area considerations, M. faveolata appears to depend on pho‐toautotrophy versus heterotrophy to a greater extent than its congener, M. cavernosa. Recent data suggest, however, that polyp size alone may not be a good indicator for differences in trophic strategies and that coordinated studies on feeding and productivity in corals are needed to better understand their ecological distributions.
Abundance and diversity of prymnesiophytes in the picoplankton coμmunity from the equatorial Pacific Ocean inferred from 18S rDNA sequences
Authors: Moon‐van der Staay Seung Yeo , van der Staay Georg W. M. , Guillou Laure , Vaulot Daniel , Claustre Herveé , Medlin Linda K.
Published: June 2010

Picoplankton, i.e., cells smaller than 2–3 μm, dominate in most open oceanic regions, such as in the Pacific Ocean. In these areas, the dominant carotenoid of photosynthetic eukaryotes is 199‐hexanoyloxyfucoxanthin (19HF), considered to be a diagnostic marker for prymnesiophytes. This suggests that this class could be a major component of eukaryotic picoplankton, despite the fact that virtually no prymnesiophyte has been described to date from this size class. To address this question, we assessed prymnesiophyte diversity and abundance in natural picoplankton coμmunities, using a molecular approach. Total genomic DNA was isolated from 3‐μm‐filtered samples collected in the Pacific Ocean. Small subunit (18S) ribosomal RNA genes (rDNA) were amplified by the polymerase chain reaction (PCR) using universal eukaryotic primers. The relative abundance of 18S rDNA from prymnesiophytes was quantified using group‐specific and eukaryotic 18S rDNA probes. The percentage of the prymnesiophyte versus total 18S rDNA was much lower than the percentage of prymnesiophytes calculated on the basis of pigment analyses for the same samples. 18S rDNA libraries from five samples were screened using a prymnesiophyte‐specific oli‐gonucleotide probe, and 14 nearly complete 18S rDNA sequences were retrieved. Phylogenetic analysis of these sequences established the presence of several prymnesiophyte lineages with no equivalent among cultivated species.
Long‐term phytoplankton‐nutrient interactions in a shallow coastal sea: Algalcommunity structure, nutrient budgets, and denitrification potential
Authors: Philippart Catharina J. M. , Cadée, Gerhard C. , van Raaphorst Wim , Riegman Roel
Published: June 2010

In the eutrophic Marsdiep, the westernmost tidal inlet of the Wadden Sea, phytoplankton biomass, and production almost doubled at the end of the 1970s and remained high ever since. Principal component analysis of 21‐yr (1974–1994) high‐resolution time series of the 32 most numerous marine algal species revealed that the phytoplankton community changed drastically both between 1976 and 1978 and again between 1987 and 1988, and that it was relatively stable in‐between (1974–1976, 1978–1987) and thereafter (1988–1994). These major changes in phytoplankton biomass and species composition coincided with changes in absolute and relative (TN:TP) nutrient concentrations. During the summer of 1977, the Marsdiep shifted from a rich, but phosphorus‐controlled system to an even more eutrophic but nitrogen‐controlled environment. The system reshifted towards P‐control between 1987 and 1988. The coincidence of the shifts in relative nutrient concentrations and phytoplankton species composition implies a strong causal relationship between TN:TP ratios and phytoplankton community structure. Among diatoms, the observed increase in phytoplankton biomass under eutrophic N‐controlled conditions was particularly due to an increase of the abundance of larger algae. Our results indicate that the N budget of the area is correlated with the community structure, suggesting enhanced loss of nitrogen to the sediment through increased deposition of larger algal cells.
Gypsum dissolution is not a universal integrator of ‘water motion’
Authors: Porter Elka T. , Sanford Lawrence P. , Suttles Steven E.
Published: June 2010

The dissolution of gypsum or plaster of Paris has been widely used as an inexpensive integral measure of ‘water motion’ in the field and in laboratory tanks for studies of physical‐biological interactions. Commonly, gypsum‐dissolution rates have been calibrated to steady flow speed or velocity in the laboratory and the calibrations have been applied to dissolution (i.e., mass‐transfer) rates in the field or in tanks. We evaluated the gypsum‐dissolution technique in a steady‐flow, a fluctuating‐flow, and a mixed‐flow environment by comparing dissolution rate to direct flow measurements with an acoustic Doppler velocimeter. We found that dissolution rates were related to steady flow and to fluctuation intensity in the exclusively steady‐flow and fluctuating‐flow environments, respectively. The relationships were weak in the mixed‐flow environment. Finally, dissolution and thus mass‐transfer relationships were different in each flow environment, and the effects of steady flow and fluctuation intensity were not additive. Providing that it is rigorously checked and appropriately calibrated, the dissolution technique can be used to measure steady flow speed or fluctuation intensity in a steady‐flow or fluctuating‐flow environment, respectively. However, comparisons of dissolution rates between steady‐flow, fluctuating‐flow, and mixed‐flow environments or within environments that change over time to determine water motion will be misleading. The gypsum‐dissolution tech‐nique can be used as a good direct indicator of mass‐transfer rates. However, mass‐transfer rates are different in different flow environments. The gypsum‐dissolution technique is not a universal integrator of ‘water motion.’
Planktonic production and respiration in oligotrophic Shield lakes
Authors: Carignan Richard , Planas Dolors , Vis Chantal
Published: June 2010

A precise oxygen method was used to measure primary production, community respiration and to determine the importance of exogenous organic carbon as an energy source to planktonic communities in the epilimnion of 12 oligotrophic to mesotrophic Shield lakes. Median photosynthetic parameters observed with the oxygen method were up to twice as high as those measured with 14C in other oligotrophic Shield lakes. Gross photosynthesis was almost always larger than community respiration, with a median P:R ratio of 1.7. We observed strong relationships between respiration and gross photosynthesis, but could not detect any significant trend between respiration or the P:R ratio and the concentration of dissolved organic carbon (DOC). DOC appeared to depress both photosynthesis and respiration. These results argue against the importance of exogenous organic carbon supply as a significant energy source to freshwater planktonic communities. Previously low P:R ratios reported for oligotrophic fresh waters may be due to the uncertain meaning of 14C production data.
Distribution and sources of cyclic pheophorbides in the marine environment
Authors: Goericke Ralf , Strom Suzanne L. , Bell Marnie A.
Published: June 2010

The labile chlorophyll a (Chl a1 ) degradation product, 132, 173‐cyclopheophorbide a enol (CPP516), was only recently found in marine sediments, where it can contribute a significant fraction to solvent‐extractable sedimentary chlorins. We developed a new chromatographic method for the analysis of CPP516 to study its distribution and sources in the marine environment. We found high concentrations of CPP516 in surficial sediments and particulate matter collected in sediment traps. It contributed 40 to 70% to the sum of all Chl a1 degradation products in fecal material from herbivorous microzooplankton and macrozooplankton. We did not find CPP516 in exponentially growing or stationary phase algal cultures. These data suggest that a major source of CPP516 is herbivores feeding on phytoplankton. We also found a series of compounds similar to CPP516 in sediments and sediment‐trap samples. Mass‐spectrometric and ultraviolet(UV)/visible‐spectrometric analyses suggest that these are CPP516 analogs of divinyl‐Chl a and Chl bs and Chl cs, conclusions that have to be confirmed by synthesis. CPP516, dissolved in organic solvents, easily degrades to 132 ‐oxopyropheophorbide a and chlorophyllone a under oxic conditions. When associated with particles, CPP516 is stable in oxic aquatic environments on a timescale of days, possibly stabilized by the chelation of metal cations. The chromophore of CPP516 differs substantially from that of other Chl a1 degradation products; it has absorption maxima at 360, 426, and 688 nm. CPP516 does not fluoresce as other Chl a1 degradation products. As a consequence, it is invisible to fluorescence‐based analyses of “pheopigments.” Thus, rates of grazing and growth derived from such measurements, as used in conjunction with the gut fluorescence and the Chl‐budget method, will be underestimates of true rates when CPP516 contributes significantly to total chlorins.