bluuebunny/crossref_metadata_2025 huggingface dataset:
The weaker language in early child bilingualism: Acquiring a first language as a second language?
Authors: MEISEL JÜRGEN M.
Published: June 2007

Past research demonstrates that first language (L1)-like competence in each language can be attained in simultaneous acquisition of bilingualism by mere exposure to the target languages. The question is whether this is also true for the “weaker” language (WL). The WL hypothesis claims that the WL differs fundamentally from monolingual L1 and balanced bilingual L1 and resembles second language (L2) acquisition. In this article, these claims are put to a test by analyzing “unusual” constructions in WLs, possibly indicating acquisition failure, and by reporting on analyses of the use of French by bilinguals whose dominant language is German. The available evidence does not justify the claim that WLs resemble L2. Instead, it shows that WL development can be delayed, but does not suggest acquisition failure. Finally, reduced input is unlikely to cause acquisition failure. The fundamental issue at stake is to explore the limits of the human language making capacity.
The future of Inuktitut in the face of majority languages: Bilingualism or language shift?
Authors: ALLEN SHANLEY
Published: June 2007

Inuktitut, the Eskimo language spoken in Eastern Canada, is one of the few Canadian indigenous languages with a strong chance of long-term survival because over 90% of Inuit children still learn Inuktitut from birth. In this paper I review existing literature on bilingual Inuit children to explore the prospects for the survival of Inuktitut given the increase in the use of English in these regions. Studies on code mixing and subject realization among simultaneous bilingual children ages 2–4 years show a strong foundation in Inuktitut, regardless of extensive exposure to English in the home. However, three studies of older Inuit children exposed to English through school reveal some stagnation in children's Inuktitut and increasing use of English with age, even in nonschool contexts. I conclude that current choices about language use at the personal, school, and societal levels will determine whether Inuit are able to reach and maintain stable bilingualism, or whether Inuktitut will decline significantly in favor of majority languages.
Political ecology of the degradation of forest commons in the Chittagong Hill Tracts of Bangladesh
Authors: RASUL GOLAM
Published: June 2007

Indigenous people have widely been blamed for degrading South Asia's montane forest resources through the practice of shifting cultivation, yet some studies have revealed that indigenous people used forests in a sustainable way for centuries until external intervention. The history of external intervention in the forests of South Asia is more than two centuries old. The process of degradation of forest resources requires understanding of the political and social processes that condition access, control and management of the land and resources involved. The Chittagong Hill Tracts (CHT) of Bangladesh, a part of the Himalayan region, underwent essentially the same socio-political and historical processes as many other countries in the region and had very similar experiences in forest management. By examination of policies and associated effects on CHT forest over the past two centuries, this paper reveals that the process of forest degradation in the CHT started during the British colonial period with the nationalization of forests, establishment of reserve forests (RFs), management of forests by government agencies and weakening of traditional institutions. The process of degradation was accelerated by: privatization of forest land for the promotion of sedentary agriculture, horticulture and rubber plantation; the construction of a hydraulic dam on the Karnafuli River; the settlement of lowland people; and the constant conflict between indigenous people and the Forest Department. The degradation of CHT forests is not only the result of traditional agricultural practices, but also of many other factors including inappropriate policies and programmes.
Environmental science, environmentalism and governance
Authors: SISSENWINE MICHAEL
Published: June 2007

Most environmental scientists care about the state of nature. They are concerned about loss of biodiversity, degradation of ecosystems services and threats to sustainability. Do such concerns and the values they reflect make an environmental scientist an environmentalist? Should they be environmentalists?
Use of sentinel chickens to study the transmission dynamics of West Nile virus in a sahelian ecosystem
Authors: CHEVALIER V. , LANCELOT R. , DIAÏTE A. , MONDET B. , De LAMBALLERIE X.
Published: June 2007

During the 2003 rainy season, a follow-up survey in sentinel chickens was undertaken to assess the seasonal transmission of West Nile virus (WNV) in a sahelian ecosystem: the Ferlo (Senegal). The estimated incidence rate in chickens was 14% (95% CI 7–29), with a very low level of transmission between July and September, and a transmission peak occurring between September and October. Comparing these results with the estimate obtained from a previous transversal serological study performed on horses the same year in the same area, the relevance of sentinel chickens in estimating the WNV transmission rate is highlighted. Conventionally adult mosquito populations disappear during the dry season but WN disease was shown to be endemic in the study area. The mechanisms of virus maintenance are discussed.
Hepatic necrosis following repair of totally anomalous pulmonary venous connection
Authors: Fischer Abigail , Long Fredrick , Feltes Timothy F.
Published: June 2007

We report a case of an infant with asplenia syndrome, isomerism of the right atrial appendages, and totally anomalous pulmonary venous connection who experienced hepatic failure following surgical correction of the anomalous pulmonary venous connection. We describe associated anomalies of the portal venous system.
Directed exospermia: I. Biological modes of resistance to UV light are implied through absorption spectroscopy of DNA and potential UV screens
Authors: Zalar Andreja , Tepfer David , Hoffmann Søren V. , Kenney John M. , Leach Sydney
Published: June 2007

Panspermia, the dissemination of life through space, would require resistance to the conditions found in space, including UV light. All known life forms depend on DNA to store information. In an effort to understand the liabilities of DNA to UV light and modes of DNA protection in terrestrial life forms, we established UV–VUV (125–340 nm) absorption spectra for dry DNA and its polymerized components and mononucleotides, as well as for a selection of potential UV screens ubiquitous in all organisms, including proteins, selected amino acids and amines (polyamines and tyramine). Montmorillonite clay was included as a potential abiotic UV screen. Among the potential screens tested, adenosine triphosphate (ATP) appeared to be particularly attractive, because its UV absorption spectrum was similar to that of DNA. We suggest that the use of ATP in UV protection could have pre-dated its current role in energy transfer. Spectroscopy also showed that UV absorption varied according to nucleotide content, suggesting that base pair usage could be a factor in adaptation to given UV environments and the availability of UV screens.
Processes controlling along‐arc isotopic variation of the southern Izu‐Bonin arc
Authors: Ishizuka Osamu , Taylor Rex N. , Yuasa Makoto , Milton J. Andy , Nesbitt Robert W. , Uto Kozo , Sakamoto Izumi
Published: June 2007

The southern Izu‐Bonin arc is the volcanic representation of Pacific Ocean lithosphere subduction beneath the oceanic crust of the Philippine Sea plate. We present new geochemical data including high‐precision Pb isotopic measurements from the 700 km length of this intraoceanic arc. An aim of this study is to link the along‐arc characteristics with variations in the subducting Pacific crust. Chemical variations have been previously recognized along the northern section of the arc as a southward decrease in 87Sr/86Sr and increase in 206Pb/204Pb. This trend continues into the southern arc as far as 27.5°N. An overall correlation between 87Sr/86Sr and fluid‐mobile element enrichment between 35 and 27.5°N implies a contribution of a slab‐derived fluid, mainly from altered oceanic crust and pelagic sediment. However, the observation that volcanoes plot systematically closer to the Northern Hemisphere Reference Line (NHRL) with increasing 206Pb/204Pb indicates that a component other than pelagic sediment and ocean crust plays a key role toward the south. South of 27.5°N, the along‐arc isotopic trend changes dramatically, with 87Sr/86Sr increasing southward from 27.5°N and the 206Pb/204Pb becoming highly radiogenic (∼19.6). This isotopic signature requires involvement of a component with high 206Pb/204Pb and low Δ8/4. Volcaniclastic sediments originating from HIMU oceanic islands on the subducting Pacific Plate are possible candidates to introduce such a component into the mantle wedge. This is consistent with the sedimentary section of ODP Site 801, located outboard of the Mariana arc which has >40% mass of HIMU volcaniclastics. An aqueous fluid, not melt, has played a major role in the source magma compositions in the 27.5–25°N segment. South of 25°N the isotopic characteristics again change significantly. 143Nd/144Nd decreases down to 0.51280, but the high 206Pb/204Pb and low Δ8/4 signatures are retained. The remarkable Th enrichment associated with low 143Nd/144Nd, Δ8/4, and Δ7/4 suggests that melting a mixture of HIMU volcaniclastics and pelagic sediment is responsible for the geochemical characteristics of this most southerly section.
MHD flow visualization of magnetopause boundary region vortices observed during high‐speed streams
Authors: Collado‐Vega Y. M. , Kessel R. L. , Shao X. , Boller R. A.
Published: June 2007

We present statistics for a total of 304 vortices found near the ecliptic plane on the magnetopause flanks, using simulated magnetohydrodynamics (MHD) data driven by real solar wind conditions. The study concentrates on 9 hours, from 29 March, 2000 UT to 30 March, 0500 UT, during the onset of a high‐speed stream that existed from 29 March to 5 April 2002. Magnetopause crossings seen by the Geotail spacecraft for the 9‐hour time interval were also analyzed and compared with the MHD simulation to validate our results. Vortices were classified by solar wind input provided by the Wind satellite located 60–80 RE upstream from Earth. Two hundred seventy‐three of the vortices were generated under northward Interplanetary Magnetic Field (IMF), and 31 were generated under southward IMF. The vortices generated under northward IMF were more prevalent on the dawnside than on the duskside and were substantially less ordered on the dawnside than on the duskside. Most of the vortices were large in scale, up to 10 RE, and with a rotation axis closely aligned with the ZSM direction. They rotated preferentially clockwise on the dawnside, and counterclockwise on the duskside. Those generated under southward IMF were less ordered, fewer in number, and also smaller in diameter. Significant vortex activity occurred on the nightside region of the magnetosphere for these southward cases in contrast to the northward IMF cases on which most of the activity was on the magnetopause flanks. The IMF is primarily northward for our time interval, and the development of these vortices with their rotation preference depending on their local time position suggest that a Kelvin‐Helmholtz (KH) instability is likely present.
Monte Carlo sensitivity analysis of land surface parameters using the Variable Infiltration Capacity model
Authors: Demaria Eleonora M. , Nijssen Bart , Wagener Thorsten
Published: June 2007

Current land surface models use increasingly complex descriptions of the processes that they represent. Increase in complexity is accompanied by an increase in the number of model parameters, many of which cannot be measured directly at large spatial scales. A Monte Carlo framework was used to evaluate the sensitivity and identifiability of ten parameters controlling surface and subsurface runoff generation in the Variable Infiltration Capacity model (VIC). Using the Monte Carlo Analysis Toolbox (MCAT), parameter sensitivities were studied for four U.S. watersheds along a hydroclimatic gradient, based on a 20‐year data set developed for the Model Parameter Estimation Experiment (MOPEX). Results showed that simulated streamflows are sensitive to three parameters when evaluated with different objective functions. Sensitivity of the infiltration parameter (b) and the drainage parameter (exp) were strongly related to the hydroclimatic gradient. The placement of vegetation roots played an important role in the sensitivity of model simulations to the thickness of the second soil layer (thick2). Overparameterization was found in the base flow formulation indicating that a simplified version could be implemented. Parameter sensitivity was more strongly dictated by climatic gradients than by changes in soil properties. Results showed how a complex model can be reduced to a more parsimonious form, leading to a more identifiable model with an increased chance of successful regionalization to ungauged basins. Although parameter sensitivities are strictly valid for VIC, this model is representative of a wider class of macroscale hydrological models. Consequently, the results and methodology will have applicability to other hydrological models.
Properties of light stratiform rain derived from 10‐ and 94‐GHz airborne Doppler radars measurements
Authors: Tian Lin , Heymsfield Gerald M. , Li Lihua , Srivastava Ramesh C.
Published: June 2007

This paper presents an initial investigation of using airborne Doppler radar operating at 10 and 94 GHz to measure the light stratiform rain (≤5 mm hr−1). It has been shown that the combination of 10 and 94 GHz is more sensitive to resolve the raindrop size distribution (RSD) in light rain than that of 14 and 35 GHz. A case of light stratiform rain over southern Florida is examined in detail in this study. Techniques for retrieving the profiles of a Gamma raindrop size distribution (RSD), vertical air velocity, and attenuation by precipitation and water vapor are presented. This approach uses the difference of the Doppler velocity at two frequencies and yields both RSD and the vertical air motion. The approach is primarily applicable to rain rates less than 5 mm hr−1. The magnitudes of the retrieved RSD are similar to those found in ground‐based observations of light stratiform rain. The retrieved vertical winds with downdrafts below about 3 km and weak updraft above are similar to what has been observed in widespread stratiform rain with melting band. The sensitivities of the retrieval to Gamma shape parameter are discussed.
Forecasting the impact of an 1859‐caliber superstorm on geosynchronous Earth‐orbiting satellites: Transponder resources
Authors: Odenwald Sten F. , Green James L.
Published: June 2007

We calculate the economic impact on the existing geosynchronous Earth‐orbiting satellite population of an 1859‐caliber superstorm event were it to occur between 2008 and 2018 during the next solar activity cycle. From a detailed model for transponder capacity and leasing, we have investigated the total revenue loss over the entire solar cycle, as a function of superstorm onset year and intensity. Our Monte Carlo simulations of 1000 possible superstorms, of varying intensity and onset year, suggest that the minimum revenue loss could be of the order of $30 billion. The losses would be larger than this if more that 20 satellites are disabled, if future launch rates do not keep up with the expected rate of retirements, or if the number of spare transponders falls below ∼30%. Consequently, revenue losses can be significantly reduced below $30 billion if the current satellite population undergoes net growth beyond 300 units during Solar Cycle 24 and a larger margin of unused transponders is maintained.
Factors influencing the residence time of catchment waters: A virtual experiment approach
Authors: Dunn Sarah M. , McDonnell Jeffrey J. , Vaché Kellie B.
Published: June 2007

Estimates of mean residence time (MRT) are increasingly used as simple summary descriptors of the hydrological processes involving storage and mixing of water within catchment systems. Current understanding of the physical controls on MRT remains limited, and various hypotheses have been proposed to explain its variability between catchments. We present a series of virtual experiments to investigate different hypotheses regarding the significance of different hydrological processes and geographical controls in determining the MRT of catchment waters. The experiments were undertaken using a semidistributed conceptual hydrological model, applied to the Maimai experimental catchment in New Zealand. Our results show that in this small steep catchment, with largely impermeable bedrock, the primary control on the stream water mean residence time is storage within the unsaturated zone. The physical location on the hillslope had only a small influence on soil water residence time. Stream water mean residence time was very sensitive to small additional amounts of deep groundwater in the model. Overall, our results suggest that stream water MRT is additive. The component residence times of stream water MRT appear relatable to characteristic properties of the catchment. Through this mechanism there is future potential for extrapolating MRT data from experimental catchments to other areas.
Biologically‐controlled multiple equilibria of tidal landforms and the fate of the Venice lagoon
Authors: Marani Marco , D'Alpaos Andrea , Lanzoni Stefano , Carniello Luca , Rinaldo Andrea
Published: June 2007

Looking across a tidal landscape, can one foresee the signs of impending shifts among different geomorphological structures? This is a question of paramount importance considering the ecological, cultural and socio‐economic relevance of tidal environments and their worldwide decline. In this Letter we argue affirmatively by introducing a model of the coupled tidal physical and biological processes. Multiple equilibria, and transitions among them, appear in the evolutionary dynamics of tidal landforms. Vegetation type, disturbances of the benthic biofilm, sediment availability and marine transgressions or regressions drive the bio‐geomorphic evolution of the system. Our approach provides general quantitative routes to model the fate of tidal landforms, which we illustrate in the case of the Venice lagoon (Italy), for which a large body of empirical observations exists spanning at least five centuries. Such observations are reproduced by the model, which also predicts that salt marshes in the Venice lagoon may not survive climatic changes in the next century if IPCC's scenarios of high relative sea level rise occur.
A 17β‐derivative of allopregnanolone is a neurosteroid antagonist at a cerebellar subpopulation of GABAAreceptors with nanomolar affinity
Authors: Maksay G , Fodor L , Bíró T , Avlonitis N , Calogeropoulou T
Published: June 2007

Background and purpose:

High‐affinity, subtype‐selective antagonists of the neurosteroid binding sites of GABAAreceptors are not available. We have characterized an allopregnanolone derivative as an antagonist of cerebellar GABAAreceptors with nanomolar affinity.

Experimental approach:

Receptor binding and electrophysiological methods were used for the allosteric modulation of cerebellar GABAAreceptors by an allopregnanolone derivative, (20R)‐17β‐(1‐hydroxy‐2,3‐butadienyl)‐5α‐androstane‐3α‐ol (HBAO). GABAAreceptors of rat cerebellar membranes were labelled with the chloride channel blocker [3H]ethynylbicycloorthobenzoate (EBOB). The ionophore function of GABAAreceptors was studied by whole‐cell patch clamp electrophysiology in cultured rat cerebellar granule and cortical cells.

Key results:

Partial displacement of cerebellar [3H]EBOB binding by nanomolar HBAO was attenuated by 0.1 mM furosemide, an antagonist of α6and β2‐3subunit‐containing GABAAreceptors. Displacement curves of HBAO were reshaped by 30 nM GABA and shifted to the right. However, the micromolar potency of full displacement by allopregnanolone was not affected by 0.1 mM furosemide or 30 nM GABA. The nanomolar, but not the micromolar phase of displacement of [3H]EBOB binding by GABA was attenuated by 100 nM HBAO. Submicromolar HBAO did not affect [3H]EBOB binding to cortical and hippocampal GABAAreceptors. HBAO up to 1 μM did not affect chloride currents elicited by 0.3‐10 μM GABA, while it abolished potentiation by 1 μM allopregnanolone with nanomolar potency in cerebellar but not in cortical cells. Furosemide attenuated cerebellar inhibition by 100 nM HBAO.

Conclusions and implications:

HBAO is a selective antagonist of allopregnanolone, a major endogenous positive modulator via neurosteroid sites of cerebellar (probably α6β2–3δ) GABAAreceptors.

British Journal of Pharmacology(2007)151, 1078–1086; doi:10.1038/sj.bjp.0707316
Stapedial Reflex and Ears With High Static Acoustic Admittance
Authors: DiGiovanni Jeffrey J. , Ries Dennis T.
Published: June 2007

Purpose

To evaluate modified acoustic reflex diagnostic protocols for a group of individuals (
n
= 9) with high peak compensated static acoustic admittance (Y
tm
) tympanograms.

Method

A modified procedure designed to improve acoustic stapedius reflex threshold (ASRT) measurements in individuals with high-admittance tympanograms was employed in both an experimental and a control group. ASRTs were measured at 0.5, 1.0, and 2.0 kHz, ipsilateral and contralateral. Measurements were obtained within each condition for 7 ear canal pressures that were set to 0, ±50, ±100, and ±150 daPa (relative to tympanometric peak pressure [TPP]).

Results

Though measuring ASRTs at −50 daPa (relative to TPP) in the high-admittance and normal groups did not result in significantly better thresholds than at TPP, the absent reflex rate was reduced when the ear canal pressure was changed by −50 daPa during ASRT measurements.

Conclusions

Based on this sample, it is suggested that a patient presenting with high peak compensated static acoustic admittance (peak Y
tm
≥ 2.1 mmho) undergo ASRT evaluation with the ear canal pressure set to −50 daPa (relative to TPP).
Central field design methods for hybrid insertion devices
Authors: Gottschalk S.C. , Quimby D.C. , Robinson K. E. , Moog E.R. , Apparao R.T.
Published: June 2007

The design of the insertion devices built and tested by STI Optronics for the Advanced Photon Source (APS) have used initial Halbach scoping followed by 2D and 3D finite element analysis (FEA). We review our design methods, which ensure the fabricated devices achieve the requested on-axis field strength, minimize pole saturation and demagnetizing fields, and reduce harmonic content, transverse roll-off, and flux leakages to desired levels. Recent enhancements include additional assessment of the effects of excessively strong magnets, magnet inhomogeneity, transverse pole saturations, part placement sensitivity, and refinements in the material databases used by the FEA.
Performance of cryogenically cooled, high-heat-load silicon crystal monochromators with porous media augmentation
Authors: Rogers C. S. , Mills D. M. , Assoufid L. , Graber T.
Published: June 2007

The performance of two Si crystal x-ray monochromators internally cooled with liquid nitrogen was tested on the F2-wiggler beamline at the Cornell High Energy Synchrotron Source (CHESS). Both crystals were (111)-oriented blocks of rectangular cross section having identical dimensions. Seven 6.4-mm-diameter coolant channels were drilled through the crystals along the beam direction. In one of the crystals, porous Cu mesh inserts were bonded into the channels to enhance the heat transfer. The channels of the second crystal were left as drilled. Symmetric, double-crystal rocking curves were recorded simultaneously for both the first and third order reflections at 8 and 24 keV. The power load on the cooled crystal was adjusted by varying the horizontal beam size using slits. The measured Si(333) rocking curve of the unenhanced crystal at 24 keV at low power was 1.9 arcsec FWHM. The theoretical width is 0.63 arcsec. The difference is due to residual fabrication and mounting strain. For a maximum incident power of 601 W and an average power density of about 10 W/mm2, the rocking curve was 2.7 arcsec. The rocking curve width for the enhanced crystal at low power was 2.4 arcsec. At a maximum incident power of 1803 W and an average power density of about 19 W/mm2, the rocking curve width was 2.2 arcsec FWHM. The use of porous mesh augmentation is a simple, but very effective, means to improve the performance of cryogenically cooled Si monochromators exposed to high power x-ray beams.
On the discrimination of dipole background from four blade photon BPMs for insertion devices (abstract)
Authors: Holldack Karsten , Peatman W. B. , Scheer M. , Klein R. , Neuber M.
Published: June 2007

The position response of blade monitors is mainly determined by their spectral sensitivity for low energy photoelectrons. For insertion devices with high energy first harmonics, the signals are contaminated by the light from the upstream and downstream bending magnets. A blade monitor design using energy selective detection of the photoelectrons from the blades will be presented. This way the background signals from the dipoles can be supressed and only position information from the insertion device beam can be obtained. A simulation code and experimental results at BESSY I will be presented.
Further properties of steady-state solutions to the Navier-Stokes problem past a three-dimensional obstacle
Authors: Galdi Giovanni P.
Published: June 2007

We show that the weak formulation of the steady-state Navier-Stokes problem in the exterior of a three-dimensional compact set (closure of a bounded domain), corresponding to a nonzero velocity at infinity and subjected to a given body force, is equivalent to a nonlinear equation in appropriate Banach spaces. We thus show that the relevant nonlinear operator enjoys a number of fundamental properties that allow us to derive many significant results for the original problem. In particular, we prove that the manifold constituted by the pairs (u,λ), with λ the nondimensional speed at infinity (Reynolds number) and u weak solution corresponding to λ and to a given body force f, is, for “generic” f, a C∞ one-dimensional manifold, and that, for almost any λ, the number of solutions is finite. We also show that, for any given f in the appropriate function space and any given λ>0, the corresponding solutions can be “controlled” by their specification only in a suitable neighborhood, I, of the boundary. The “size” of I depends only on λ and f. Furthermore, we analyze the steady bifurcation properties of branches of these solutions and prove that, in some important cases, the sufficient conditions for bifurcation formally coincide with the analogous ones for flow in a bounded domain. Finally, the stability of these solutions is analyzed. The paper ends with a section on relevant open questions.
CTLA-4: From conflict to clinic
Authors: Bashyam Hema
Published: June 2007

CTLA-4 was first identified in 1991 as a second receptor for the T cell costimulation ligand B7. Uncertainties about its biological function plagued the early years after its discovery until 1995, when it was confirmed to be an inhibitor of T cell responses. CTLA-4 has since scored in the clinic as a target for antitumor therapy and as a soluble inhibitor of autoimmunity.
Methicillin Resistance and Risk Factors for Embolism inStaphylococcus aureusInfective Endocarditis
Authors: Hsu Ron-Bin , Lin Fang-Yue
Published: June 2007

Objective.

Infective endocarditis caused byStaphylococcus aureusis an ominous prognosis associated with a high prevalence of embolic episodes and neurological involvement. Whether methicillin resistance decreases the risk of embolism in infective endocarditis is unclear. We sought to assess the association between methicillin resistance and risk factors for embolism in S.aureusinfective endocarditis.

Design.

Retrospective chart review. Data from patients with infective endocarditis due to methicillin-resistantS. aureus werecompared with data from patients with endocarditis due to methicillin-susceptibleS. aureus.Logistic regression was used to identify independent risk factors for embolism.

Setting.

A 2,000-bed, university-affiliated tertiary care hospital.

Patients.

Between 1995 and 2005, 123 patients withS. aureusinfective endocarditis were included in the study. There were 74 male patients and 49 female patients, with a median age of 54 years (range, 0-89 years).

Results.

Of 123 infections, 30 (24%) were nosocomial infections, and 14 (11%) were prosthetic valve infections. Of 123S. aureusisolates, 48 (39%) were methicillin resistant. In total, embolism occurred in 45 (37%) of these patients: pulmonary embolism in 22 (18%), cerebral embolism in 21 (17%), and peripheral embolism in 6 (5%). The independent risk factors for an embolism were injection drug use, presence of a cardiac vegetation with a size of 10 mm or greater, and absence of nosocomial infection. For 83 patients with aortic or mitral infective endocarditis, independent risk factors for an embolism were the presence of a cardiac vegetation with a size of 10 mm or greater and endocarditis due to methicillin-susceptibleS. aureus.Overall, in-hospital death occurred for 32 (26%) of 123 Patients. Methicillin-resistant infection was not an independent risk factor for death.

Conclusions.

Methicillin-resistant S.aureusinfection was associated with decreased risk of embolism in left-side endocarditis, but was not associated with in-hospital death.
Costs of Management of Occupational Exposures to Blood and Body Fluids
Authors: O'Malley Emily M. , Scott R. Douglas , Gayle Julie , Dekutoski John , Foltzer Michael , Lundstrom Tammy S. , Welbel Sharon , Chiarello Linda A. , Panlilio Adelisa L.
Published: June 2007

Objective.

To determine the cost of management of occupational exposures to blood and body fluids.

Design.

A convenience sample of 4 healthcare facilities provided information on the cost of management of occupational exposures that varied in type, severity, and exposure source infection status. Detailed information was collected on time spent reporting, managing, and following up the exposures; salaries (including benefits) for representative staff who sustained and who managed exposures; and costs (not charges) for laboratory testing of exposure sources and exposed healthcare personnel, as well as any postexposure prophylaxis taken by the exposed personnel. Resources used were stratified by the phase of exposure management: exposure reporting, initial management, and follow-up. Data for 31 exposure scenarios were analyzed. Costs were given in 2003 US dollars.

Setting.

The 4 facilities providing data were a 600-bed public hospital, a 244-bed Veterans Affairs medical center, a 437-bed rural tertiary care hospital, and a 3,500-bed healthcare system.

Results.

The overall range of costs to manage reported exposures was $71-$4,838. Mean total costs varied greatly by the infection status of the source patient. The overall mean cost for exposures to human immunodeficiency virus (HIV)-infected source patients (n = 19, including those coinfected with hepatitis B or C virus) was $2,456 (range, $907-$4,838), whereas the overall mean cost for exposures to source patients with unknown or negative infection status (n = 8) was $376 (range, $71-$860). Lastly, the overall mean cost of management of reported exposures for source patients infected with hepatitis C virus (n = 4) was $650 (range, $186-$856).

Conclusions.

Management of occupational exposures to blood and body fluids is costly, the best way to avoid these costs is by prevention of exposures.
Controlling for Severity of Illness in Assessment of the Association Between Antimicrobial-Resistant Infection and Mortality: Impact of Calculation of Acute Physiology and Chronic Health Evaluation (APACHE) II Scores at Different Time Points
Authors: Hamilton Keith W. , Bilker Warren B. , Lautenbach Ebbing
Published: June 2007

Background.

In studies of the association between antibiotic-resistant infection and mortality, the importance of controlling for the underlying severity of illness is well recognized. However, it is unclear when the severity of illness should be assessed. Controlling for severity of illness on the day the culture specimen is obtained may underestimate the true association between resistance and mortality.

Objective.

TO assess the impact of calculating the Acute Physiology and Chronic Health Evaluation (APACHE) II score at different time points on the association between antimicrobial resistance and mortality.

Methods.

We used an existing data set from a study that investigated the association between fluoroquinolone resistance and mortality. The APACHE II score was calculated at 3 time points: the day the culture specimen was obtained, 1 day before the culture specimen was obtained, and 2 days before the culture specimen was obtained. Separate multivariable models were constructed using the 3 different APACHE II scores. These models were compared qualitatively.

Results.

Of 91 total subjects, 51 were infected with a fluoroquinolone-resistant strain and 40 with a fluoroquinolone-susceptible strain. The median APACHE II score for all subjects was 13 (95% confidence interval [CI], 11-15) when calculated on the day the culture specimen was obtained, 12 (95% CI, 11-13) when calculated 1 day before, and 11 (95% CI, 10-13) when calculated 2 days before the culture specimen was obtained. Of 91 subjects, 12 (13.2%) died. The 3 multivariable models (each with the APACHE II score calculated on a different day) were not substantively different; the adjusted odds ratio for the association between fluoroquinolone-resistant infection and mortality varied only from 1.38 to 1.65 in the 3 models.

Conclusions.

APACHE II scores calculated at different time points relative to obtainment of the culture specimen did not differ substantively. Furthermore, when the adjusted association between fluoroquinolone resistance and mortality was assessed, there were no substantive differences across multivariable models that incorporated APACHE II scores calculated at different time points.
Role of Dipstick Testing in the Evaluation of Urinary Tract Infection in Nursing Home Residents
Authors: Juthani-Mehta Manisha , Tinetti Mary , Perrelli Eleanor , Towle Virginia , Quagliarello Vincent
Published: June 2007

Among 101 nursing home residents with suspected urinary tract infection (UTI), we determined the negative predictive value of dipstick testing for leukocyte esterase and nitrite to be 100% (95% confidence interval, 74%-100%), compared with laboratory evidence of UTI (greater than 10 white blood cells/mm3on urinalysis and greater than 100,000 colony forming units/mL on urine culture). Nursing home dipstick testing effectively excluded the possibility of UTI.
Impact of Freezing on the Future Utility of Archived Surveillance Culture Specimens
Authors: Green Heather P. , Johnson Judith A. , Furuno Jon P. , Strauss Sandra M. , Perencevich Eli N. , Lautenbach Ebbing , Lee Dong , Harris Anthony D.
Published: June 2007

The ability to recover bacteria from frozen culture specimens has important implications. The purpose of this study was to validate the utility of frozen specimens for recovery of several gram-positive and gram-negative bacterial species by culture. Results demonstrate that 98% of 250 bacterial isolates identified on initial culture were subsequently recovered by culture of frozen specimens after a median storage period of 564 days.
Reduction in Hospitalwide Incidence of Infection or Colonization with Methicillin-ResistantStaphylococcus aureusWith Use of Antimicrobial Hand-Hygiene Gel and Statistical Process Control Charts
Authors: Harrington Glenys , Watson Kerrie , Bailey Michael , Land Gillian , Borrell Susan , Houston Leanne , Kehoe Rosaleen , Bass Pauline , Cockroft Emma , Marshall Caroline , Mijch Anne , Spelman Denis
Published: June 2007

Objective.

To evaluate the impact of serial interventions on the incidence of methicillin-resistantStaphylococcus aureus(MRSA).

Design.

Longitudinal observational study before and after interventions.

Setting.

The Alfred Hospital is a 350-bed tertiary referral hospital with a 35-bed intensive care unit (ICU).

Interventions.

A series of interventions including the introduction of an antimicrobial hand-hygiene gel to the intensive care unit and a hospitalwide MRSA surveillance feedback program that used statistical process control charts but not active surveillance cultures.

Methods.

Serial interventions were introduced between January 2003 and May 2006. The incidence and rates of new patients colonized or infected with MRSA and episodes of MRSA bacteremia in the intensive care unit and hospitalwide were compared between the preintervention and intervention periods. Segmented regression analysis was used to calculate the percentage reduction in new patients with MRSA and in episodes of MRSA bacteremia hospitalwide in the intervention period.

Results.

The rate of new patients with MRSA in the ICU was 6.7 cases per 100 patient admissions in the intervention period, compared with 9.3 cases per 100 patient admissions in the preintervention period (P= .047). The hospitalwide rate of new patients with MRSA was 1.7 cases per 100 patient admissions in the intervention period, compared with 3.0 cases per 100 patient admissions in the preintervention period (P< .001). By use of segmented regression analysis, the maximum and conservative estimates for percentage reduction in the rate of new patients with MRSA were 79.5% and 42.0%, respectively, and the maximum and conservative estimates for percentage reduction in the rate of episodes of MRSA bacteremia were 87.4% and 39.0%, respectively.

Conclusion.

A sustained reduction in the number of new patients with MRSA colonization or infection has been demonstrated using minimal resources and a limited number of interventions.
Mutations inArabidopsis Multidrug Resistance-LikeABC Transporters Separate the Roles of Acropetal and Basipetal Auxin Transport in Lateral Root Development
Authors: Wu Guosheng , Lewis Daniel R. , Spalding Edgar P.
Published: June 2007

Auxin affects the shape of root systems by influencing elongation and branching. Because multidrug resistance (MDR)-like ABC transporters participate in auxin transport, they may be expected to contribute to root system development. This reverse genetic study of Arabidopsis thaliana roots shows that MDR4-mediated basipetal auxin transport did not affect root elongation or branching. However, impaired acropetal auxin transport due to mutation of the MDR1 gene caused 21% of nascent lateral roots to arrest their growth and the remainder to elongate 50% more slowly than the wild type. Reporter gene analyses indicated a severe auxin deficit in the apex of mdr1 but not mdr4 lateral roots. The mdr1 deficit was explained by 40% less acropetal auxin transport within the mdr1 lateral roots. The slow elongation of mdr1 lateral roots was rescued by auxin and phenocopied in the wild type by an inhibitor of polar auxin transport. Confocal microscopy analysis of a functional green fluorescent protein–MDR1 translational fusion showed the protein to be auxin inducible and present in the tissues responsible for acropetal transport in the primary root. The protein also accumulated in lateral root primordia and later in the tissues responsible for acropetal transport within the lateral root, fully supporting the conclusion that auxin levels established by MDR1-dependent acropetal transport control lateral root growth rate to influence root system architecture.
Cell cycle dependency of caspase activation in Fas‐induced apoptosis in leukemia cells
Authors: Li Yufeng , Dida Francis , Iwao Atsushi , Deguchi Takao , Azuma Eiichi , Komada Yoshihiro
Published: June 2007

The relationship between apoptosis and the cell cycle remains unclear. In the present study we have investigated the relationship between cell cycle progression and the activation of caspases (caspase‐3 and caspase‐8) in Fas (CD95)‐mediated apoptosis in asynchronously growing leukemia cells. We found that cells expressing the active form of caspase‐3 were cyclin A/B1 and Ki‐67 negative but cyclin E positive, whereas expression of the active form of caspase‐8 was detected in cyclin A/B1/E‐negative and Ki‐67‐negative cells. In addition, both the activation of caspases and Fas‐mediated apoptosis were completely abolished when leukemia cells were arrested in early G1 phase. Using post‐sorting western blot analysis, we demonstrated that caspase‐3 and caspase‐8 were activated in p27‐negative cells. These results suggest that caspase‐3 would be activated in cells entering into late G1 or early S phase, and caspase‐8 would be activated in middle or late G1 phase. The speed of cell cycle progression from G1 to S phase might be influential in the speed of caspase activation and induction of Fas‐mediated apoptosis. (Cancer Sci 2007; 98: 1174–1183)
Neuromuscular complications of thyrotoxicosis
Authors: Kung Annie W. C.
Published: June 2007

Thyroid hormones exert multiple effects on the neuromuscular system and the brain, with the most important being their role in stimulating the development and differentiation of the neuromuscular system and brain in foetal and neonatal life. In the presence of hyperthyroidism, muscular and neurological symptoms may be the presenting clinical features of the disease. The frequency and severity of neuromuscular complications vary considerably and are probably related to the degree of hyperthyroidism, although in some patients the neuromuscular dysfunction is caused by associated disorders rather than by hyperthyroidism per se. This update focuses on the most common neurological and muscular disorders that occur in patients with thyrotoxicosis. It is beyond the scope of this paper to discuss thyroid eye disease and cardiac complications, in themselves separate complications of specific myocytes.
Preoperative undetectable serum thyroglobulin in differentiated thyroid carcinoma: incidence, causes and management strategy
Authors: Giovanella Luca , Ceriani Luca , Ghelfo Antonella , Maffioli Marco , Keller Franco
Published: June 2007

Background  In recent years serum thyroglobulin (Tg) measurement during thyroxine (T4) treatment and/or after stimulation by endogenous TSH or recombinant human TSH (rhTSH) has eclipsed other diagnostic procedures in managing patients with differentiated thyroid cancer (DTC). However, preoperative undetectable Tg was reported in up to 12% of patients affected by DTC and recurrences of DTC with no increase in serum Tg have also been described. Clearly, a negative Tg measurement may falsely reassure both the patient and the clinician in these cases.

Aim  We retrospectively evaluated the incidence of undetectable or reduced preoperative serum Tg in a group of 436 patients affected by DTC. Additionally, we evaluated the role of Tg retesting by two different immunoassays in patients with low Tg at first measurement.

Methods  We retrospectively selected 17 patients with undetectable (i.e. less than functional sensitivity of assay method) or reduced Tg (i.e. between functional sensitivity and minimum normal value) among 436 patients with histologically proved DTC. The remaining 419 patients were used as control cases. Frozen sera from all patients were retested by two different Tg immunoassays.

Results  Globally, 17 out of 436 (3·8%) patients showed undetectable (n = 5, 1·1%) or reduced (n = 12, 2·7%) preoperative Tg. The Tg level was above the minimum normal value in 3 and 4 out of 5, and 8 and 9 out of 12 of these patients, respectively, when two different immunoassays were employed. On the other hand, undetectable or reduced Tg levels were found in 3·0%–5·1% of control cases when different immunoassays were used.

Conclusions  Regardless of the method employed, 3·0–5·1% of patients with DTC showed undetectable or reduced preoperative Tg. This fact must be recognized, as Tg cannot be used as a benchmark for DTC follow‐up in these cases. However, Tg retesting with different immunoassays seems to be useful in ruling out these pitfalls in a large majority of patients, and also indicates the most effective assay to be employed in these cases.
Enhanced exoenzyme activities in sediments in the presence of deposit‐feeding Chironomus riparius larvae
Authors: STIEF PETER
Published: June 2007

1. The combined effects of deposit‐feeding, bioturbation and bioirrigation by benthic macrofauna on the enzymatic hydrolysis of organic matter were studied in microcosms. Chironomus riparius larvae (Insecta, Diptera) served as model macrofauna and stinging nettle leaves (Urtica dioica) were used as a detrital food source.

2. In the upper 10 mm of the sediment (the habitat of C. riparius larvae), the activities of several exoenzymes, the contents of several fractions of particulate organic matter (POM), and the concentrations of dissolved oxidants (O2, NO) were measured on a small scale. Fluorescent particles (luminophores) were used to quantify the vertical redistribution of particles within the same layer.

3. In control sediment, the addition of detrital food enhanced exoenzyme activities in the 0–2 mm layer only. In the presence of C. riparius larvae, exoenzyme activities increased to 10 mm depth. Further, the content of POM in the 0–2 mm layer was lower in the presence than in the absence of larvae, suggesting ingestion and subduction of the added detritus. After prolonged incubation without further food addition, exoenzyme activities returned close to background values in both treatments, whereas the vertical distribution of POM remained unchanged.

4. The overall penetration depth of O2 and NO into the sediment was greater in the presence than the absence of C. riparius, the differences being more pronounced after prolonged incubation. Locally high O2 and NO concentrations due to bioirrigation by C. riparius were measured deep in the sediment. Net downward transport of particles was observed only in the presence of C. riparius larvae and only at the beginning of the incubation.

5. I conclude that deposit‐feeding and bioturbation by macrofauna can quickly remove freshly deposited POM from the sediment surface and transfer it to less oxygenated sites (i.e. animal guts and deep sediment layers). Bioirrigation also increases the availability of oxidants deep in the sediment. The oscillation of oxidant supply to POM particles by ingestion–egestion, burial and re‐burial, and the intermittent bioirrigation of subsurface sediment, is probably the cause of the increased rate of organic matter hydrolysis, the rate‐limiting step in mineralization.