bluuebunny/crossref_metadata_2025 huggingface dataset:
Developmental differences and a test for reciprocity in the tolerance of Chaoborus punctipennis larvae to ultraviolet radiation
Authors: Persaud A D , Yan N D
Published: April 2005

We estimated the ultraviolet radiation (UVR) tolerance of Chaoborus punctipennis in five 2- to 4-day in situ experiments conducted with third and fourth instar larvae at 0.25, 1.25, 3.0, and 5.0 m in Ruth Roy Lake, a lake with low dissolved organic carbon levels (0.2 mg·L1). UVR tolerance increased with larval age. Third and late fourth instar LD50 (median lethal dose) ranged from 52.3 to 62.2 J·cm2 and from 82.4 to 119.6 J·cm2, respectively, among the four depths. Reciprocity held for UVR exposure down to 5.0 m, i.e., toxicity was independent of dose rate. At any given depth, the LT50 (median lethal time) increased with larval stage, but even at 5.0 m, third and late fourth instars died in less than 10 and 20 h, respectively, under sunny skies. These results suggest that Chaoborus abundance and distribution might be affected by UVR, especially in clear lakes. If UVR levels continue to increase in some lakes because of stratospheric ozone loss and climate change, we predict that UVR damage to Chaoborus will increase in the future, thereby affecting trophic interactions in temperate freshwater food webs.
Marine nitrogen in central Idaho riparian forests: evidence from stable isotopes
Authors: Koyama Akihiro , Kavanagh Kathleen , Robinson Andrew
Published: April 2005

Terrestrial and marine ecosystems are linked by the annual migration of salmonids. We examined the contribution of anadromous fish to foliar nitrogen (N) in central Idaho riparian forests where anadromous fish have been in sharp decline for approximately 30 years. To determine if the amount of N from anadromous fish carcasses can be assessed from conifer foliage, we fertilized seedlings with varying proportions of N from marine sources and analyzed their foliar 15N/14N ratio (δ15N). Also, to evaluate whether N obtained from marine sources was evident in riparian forests, we analyzed the δ15N of conifer foliage, above and below waterfalls, along historically salmon-bearing and non-salmon-bearing streams and rivers in central Idaho. In the seedling study, the amount of marine N was positively correlated with foliar δ15N. Furthermore, we determined that foliar δ15N values in riparian forests were explained by the historical occurrence of salmon. Foliar δ15N declined significantly from bankside to upslope trees in transects along salmon-bearing streams and rivers, whereas there was no significant gradient along transects perpendicular to non-salmon-bearing reaches. We therefore conclude that marine nutrient sources have historically contributed to the N pool in riparian conifer forests and marine N persisted following 30 years of severe populations declines.
Metal bioaccumulation and oxidative stress in yellow perch (Perca flavescens) collected from eight lakes along a metal contamination gradient (Cd, Cu, Zn, Ni)
Authors: Giguère Anik , Campbell Peter GC , Hare Landis , Cossu-Leguille Carole
Published: April 2005

Links among metal exposure, metal accumulation, and metal-induced effects were explored in indigenous yellow perch (Perca flavescens) collected from eight lakes located along a metal concentration gradient in two mining regions. Fish exposure to Cd, Cu, Ni, and Zn was estimated on the basis of calculated free metal ion concentrations in lake waters. Hepatic metal concentrations were determined and various markers of oxidative stress were measured to assess metal effects in liver cells. Accumulated metals were not consistently related to ambient free metal ion concentrations, possibly because of unaccounted for fluctuations in lake water metal concentrations. Accumulated metals were associated with limited oxidative stress in perch livers, as evidenced by reductions in glutathione concentrations and glutathione reductase activities. However, this stress appeared to be minor, since increasing hepatic Cu concentrations were associated with reduced lipid peroxidation, a response opposite to that predicted from basic principles. Our results suggest that oxidative stress will not have direct repercussions on the health of the perch at the individual level. We speculate that the observed increase in metallothionein concentrations with increasing accumulated metals might afford protection against reactive oxygen species.
Using geostatistics to quantify seasonal distribution and aggregation patterns of fishes: an example of Atlantic cod (Gadus morhua)
Authors: Mello L GS , Rose G A
Published: April 2005

Geostatistical methods were used to (i) quantify fish aggregation patterns over a range of scales (100 m to 67 km) using both simulated and acoustic density data of Atlantic cod (Gadus morhua) and (ii) examine how changes in aggregation patterns influenced the precision of geostatistical density indices. Variogram parameters (range, sill, and nugget) reflected changes in distribution patterns. Variograms of dispersed and low-density aggregations had large range and small sill and nugget values. In contrast, when fish were aggregated in a small portion of the study area, the range was low and the sill and nugget large. The precision of density indices (coefficient of variation) was below 20% in all cases but at a maximum during summer when cod were broadly distributed in small, moderate to dense aggregations. Geostatistical modeling allowed us to describe and quantify distribution patterns of fish density over different scales of observation, comparisons of spatiotemporal changes in density distribution, and estimations of the precision of density indices while accounting for the effects of heterogeneous distributions, outliers and the typically large number of zero and low-density observations. Geostatistical methods have particular applicability to fishes exhibiting gregarious behaviour and seasonally variable distributions, which include many temperate and high-latitude fish species.
Summer and fall habitat of North Atlantic right whales (Eubalaena glacialis) inferred from satellite telemetry
Authors: Baumgartner Mark F , Mate Bruce R
Published: April 2005

Satellite-monitored radio tags were attached to North Atlantic right whales (Eubalaena glacialis) in Grand Manan Basin of the lower Bay of Fundy during the summer and early fall seasons of 19891991 and 2000. Monte Carlo tests were used to examine the distribution of the tagged whales in space and time and with respect to a variety of environmental variables to characterize right whale habitat on their northern feeding grounds. These environmental variables included depth, depth gradient, climatological surface and bottom hydrographic properties, and remotely sensed surface temperature, chlorophyll concentration, and their respective horizontal gradients. Site fidelity in the Bay of Fundy was very low during 19891991 and high during 2000. When the tagged animals left the Bay, they did not frequently visit the deep basins of the Gulf of Maine and Scotian Shelf, where abundances of their primary copepod prey, Calanus finmarchicus, are thought to be high. Instead, right whales visited areas characterized by low bottom water temperatures, high surface salinity, and high surface stratification. No evidence was found that the tagged right whales associated with oceanic fronts or regions with high standing stocks of phytoplankton.
Spatial and temporal gradients in artisanal fisheries of a large Neotropical reservoir, the Itaipu Reservoir, Brazil
Authors: Okada Edson Kiyoshi , Agostinho Angelo Antonio , Gomes Luiz Carlos
Published: April 2005

Physical, chemical, and biological gradients along reservoirs are clear and exhibit marked spatial and temporal variations. These variations are rarely quantified and may produce spatial gradients in fisheries. We analyzed trends in total yield and gradients and relationships between catch-per-unit-effort (CPUE) and some characteristics of the fishery in the large Neotropical Itaipu Reservoir in Brazil. Data on the artisanal fisheries were collected over an 11-year period (414 213 daily trips). Annual yield (especially after 1993) and CPUE (annual total and for each species) decreased over the studied period. A clear longitudinal pattern in the CPUE values for the main species was recognized, and this pattern presented a significant relationship with the type of gear and characteristics of the vessels used in the fisheries. The decline in yield and CPUE is apparently due to changes in trophic state, as well as to the construction of reservoirs upstream from the region and to overfishing. It is clear that the spatial zonation influenced fish species distribution along the reservoir and, therefore, the fishery. We conclude that for this large Neotropical reservoir, spatial gradient cannot be ignored in management plans, and this appears to be true for any reservoir that exhibits zonation.
Inhibitory effect of sodium fluoride and chlorhexidine on the growth of oral lactobacilli
Authors: del Carmen Ahumada Ostengo María , Wiese Birgitt , Nader-Macias María Elena
Published: April 2005

The accumulation of microorganisms in dental plaque is related to the etiology of caries and periodontal disease, with a high prevalence worldwide. The prophylactic measures include the use of chemical agents as NaF and chlorhexidine. Lactic acid bacteria are members of the normal microbiota of the oral cavity being discussed with regard to their beneficial or detrimental effect in this environment. The present study was performed to determine the growth of some species of Lactobacillus at different concentrations of NaF and chlorhexidine. The strains were isolated from both caries-free and caries patients. Their growth parameters were evaluated by the application of the Gompertz model to the experimental data of optical density as a measurement of growth. The degree of inhibition of the growth of all of the lactobacilli studied was different, depending on each particular strain. NaF at 1 mmol·L–1 inhibited between 5% and 46%, at 5 mmol·L–1 between 13% and 65%, and at 20 mmol·L–1 between 57% and 84%. CHX at higher concentrations (197 and 98 mmol·L–1) showed a complete inhibition of some of the strains. The significance of the results was evaluated by the application of a multivariate analysis and also compared with the inhibition of pathogenic Streptococcus mutans and with lactobacilli strains from collection cultures.Key words: oral lactobacilli, sodium fluoride, chlorhexidine, growth inhibition, growth parameters, Gompertz model.
Ecology and natural history of the protochordates
Authors: Lambert Gretchen
Published: April 2005

The last comprehensive reviews of ecology and natural history of ascidians were included in the excellent 1971 publication by Millar on the biology of ascidians and the 1991 treatise on New Caledonia ascidians by Monniot, Monniot, and Laboute. Several hundred papers have been published since that time, greatly expanding our knowledge of environmental tolerances and responses to increasing levels of anthropogenically derived toxins in marine waters, energetics and feeding strategies, predator–prey relationships, competition both intra- and inter-specific that include many studies of self–nonself recognition in colonial species, modes and environmental regulation of reproduction and development, symbionts, natural-product chemistry as antifouling and antipredator defenses, and dispersal mechanisms. The relatively new field of molecular genetics is revealing the presence of cryptic species and is helping to determine the origin of anthropogenically transported individuals, an important and growing problem that affects natural ecological relationships in marine communities worldwide. We are learning more about the difficult-to-study abyssal and Antarctic species. There have been great advances in our understanding of the importance in open-ocean food webs of the planktonic Appendicularia and Thaliacea. Also included in this review is a brief discussion of recent work on the Cephalochordata and Hemichordata.
Eutely, cell lineage, and fate within the ascidian larval nervous system: determinacy or to be determined?
Authors: Meinertzhagen Ian A
Published: April 2005

The larval central nervous system (CNS) of the ascidian Ciona intestinalis (L., 1767) arises from an embryonic neural plate and contains sufficiently few cells, about 330, to enable definitive counts. On the basis of such counts, there is evidence both for cell constancy (eutely) in the larval CNS and for small variations in the overall numbers of cells and among defined cell types within this total. However, evidence for the range of such deviations and the existence of a true phenotypic wild type are lacking. The record of cell lineage, i.e., the mitotic ancestry of each cell, and the fates of some of these cells have recently received increased documentation in both the genus Ciona and Halocynthia roretzi (von Drasche, 1884). Relatively few generations of cells, between 10 and 14, form the entire CNS in C. intestinalis, and cell death does not occur prior to larval hatching. The tiny complement of larval CNS cells can therefore be seen as the product of a small fixed number of determinate cleavages, and variations in cell number as the product of minor deviations in this mitotic ancestry. Within these lineage records, some cell fates have already been identified, but knowledge of most is lacking because the cells lack markers or other identifying features. Nevertheless, this tiny nervous system offers the prospect that all its cells can one day be identified, and their developmental histories and larval functions analyzed, cell by cell.
Historical introduction, overview, and reproductive biology of the protochordates
Authors: Lambert Charles C
Published: April 2005

This issue of the Canadian Journal of Zoology exhaustively reviews most major aspects of protochordate biology by specialists in their fields. Protochordates are members of two deuterostome phyla that are exclusively marine. The Hemichordata, with solitary enteropneusts and colonial pterobranchs, share a ciliated larva with echinoderms and appear to be closely related, but they also have many chordate-like features. The invertebrate chordates are composed of the exclusively solitary cephalochordates and the tunicates with both solitary and colonial forms. The cephalochordates are all free-swimming, but the tunicates include both sessile and free-swimming forms. Here I explore the history of research on protochordates, show how views on their relationships have changed with time, and review some of their reproductive and structural traits not included in other contributions to this special issue.
The nervous system in adult tunicates: current research directions
Authors: Mackie G O , Burighel P
Published: April 2005

This review covers 25 years of progress on structural, functional, and developmental neurobiology of adult tunicates. The focus is on ascidians rather than pelagic species. The ascidian brain and peripheral nervous system are considered from the point of view of ultrastructure, neurotransmitters, regulatory peptides, and electrical activity. Sensory reception and effector control are stressed. Discussion of the dorsal strand plexus centres on its relationship with photoreceptors, the presence in it of gonadotropin-releasing hormone and its role in reproductive control. In addition to hydrodynamic sense organs based on primary sensory neurons (cupular organs), ascidians are now known to have coronal sense organs based on axonless hair cells resembling those of the vertebrate acustico-lateralis system. The peripheral nervous system is remarkable in that the motor neuron terminals are apparently interconnected synaptically, providing the equivalent of a nerve net. Development of the neural complex in ascidians is reviewed, highlighting recent embryological and molecular evidence for stomodeal, neurohypophyseal, and atrial placodes. The nervous system forms similarly during embryogenesis in the oozooid and blastogenesis in colonial forms. The regeneration of the brain in Ciona intestinalis (L., 1767) is discussed in relation to normal neurogenesis. Finally, the viviparous development of salps is considered, where recent work traces the early development of the brain, outgrowth of nerve roots, and the targetting of motor nerves to the appropriate muscles.
PREDICTION OF SEVERE THUNDERSTORMS WITH MINIMALA PRIORIINFORMATION
Authors: CHAUDHURI SUTAPA , CHATTOPADHYAY SURAJIT
Published: April 2005

A genetic algorithm (GA) is introduced to fix ranges of parameters, in a quantitative manner, pertaining to forecasting the genesis of severe thunderstorms in the pre-monsoon season over Calcutta (22°32′, 88°20′) in the northeastern part of India (20°–24°N latitude, 85°–93°E longitude). The results depict that definite quantitative ranges of parameters can be made available before as well as after the occurrence of severe thunderstorms using a GA. Thus, a suitable combination of these ranges of parameters before the onset can represent a possible predictor of thunderstorm genesis.
Acute hypoosmolality attenuates the suppression of cutaneous vasodilation with increased exercise intensity
Authors: Mitono Hiroyuki , Endoh Hiroshi , Okazaki Kazunobu , Ichinose Takashi , Masuki Shizue , Takamata Akira , Nose Hiroshi
Published: April 2005

We examined the hypothesis that elevation of the body core temperature threshold for forearm skin vasodilation (THFVC) with increased exercise intensity is partially caused by concomitantly increased plasma osmolality (Posmol). Eight young male subjects, wearing a body suit perfused with warm water to maintain the mean skin temperature at 34 ± 1°C (ranges), performed 20-min cycle-ergometer exercise at 30% peak aerobic power (V̇o2 peak) under isoosmotic conditions (C), and at 65% V̇o2 peak under isoosmotic (HEXIOS) and hypoosmotic (HEXLOS) conditions. In HEXLOS, hypoosmolality was attained by hypotonic saline infusion with DDAVP, a V2 agonist, before exercise. Posmol (mosmol/kgH2O) increased after the start of exercise in both HEX trials ( P < 0.01) but not in C. The average Posmol at 5 and 10 min in HEXIOS was higher than in C ( P < 0.01), whereas that in HEXLOS was lower than in HEXIOS ( P < 0.01). The change in THFVC was proportional to that in Posmol in every subject for three trials. The change in THFVC per unit change in Posmol (ΔTHFVC/ΔPosmol, °C·mosmol−1·kgH2O−1) was 0.064 ± 0.012 when exercise intensity increased from C to HEXIOS, similar to 0.086 ± 0.020 when Posmol decreased from HEXIOS to HEXLOS ( P > 0.1). Moreover, there were no significant differences in plasma volume, heart rate, mean arterial pressure, and plasma lactate concentration around THFVC between HEXIOS and HEXLOS ( P > 0.1). Thus the increase in THFVC due to increased exercise intensity was at least partially explained by the concomitantly increased Posmol.
Determinants of Spatial and Temporal Coding by Semicircular Canal Afferents
Authors: Highstein Stephen M. , Rabbitt Richard D. , Holstein Gay R. , Boyle Richard D.
Published: April 2005

The vestibular semicircular canals are internal sensors that signal the magnitude, direction, and temporal properties of angular head motion. Fluid mechanics within the 3-canal labyrinth code the direction of movement and integrate angular acceleration stimuli over time. Directional coding is accomplished by decomposition of complex angular accelerations into 3 biomechanical components—one component exciting each of the 3 ampullary organs and associated afferent nerve bundles separately. For low-frequency angular motion stimuli, fluid displacement within each canal is proportional to angular acceleration. At higher frequencies, above the lower corner frequency, real-time integration is accomplished by viscous forces arising from the movement of fluid within the slender lumen of each canal. This results in angular velocity sensitive fluid displacements. Reflecting this, a subset of afferent fibers indeed report angular acceleration to the brain for low frequencies of head movement and report angular velocity for higher frequencies. However, a substantial number of afferent fibers also report angular acceleration, or a signal between acceleration and velocity, even at frequencies where the endolymph displacement is known to follow angular head velocity. These non-velocity-sensitive afferent signals cannot be attributed to canal biomechanics alone. The responses of non-velocity-sensitive cells include a mathematical differentiation (first-order or fractional) imparted by hair-cell and/or afferent complexes. This mathematical differentiation from velocity to acceleration cannot be attributed to hair cell ionic currents, but occurs as a result of the dynamics of synaptic transmission between hair cells and their primary afferent fibers. The evidence for this conclusion is reviewed below.
Temporal Representation of the Delay of Iterated Rippled Noise in the Dorsal Cochlear Nucleus
Authors: Neuert Veronika , Verhey Jesko L. , Winter Ian M.
Published: April 2005

It has been suggested that the dorsal cochlear nucleus (DCN) is involved in the temporal representation of both envelope periodicity and pitch. This hypothesis is tested using iterated rippled noise (IRN), which is generated by a cascade of delay and add [IRN(+)] or delay and subtract [IRN(−)] operations. The autocorrelation functions (ACFs) of the waveform and the envelope of IRN(+) have a first peak at the delay, which corresponds to the perceived pitch of the IRN. With the same delay, the pitch of IRN(−) is generally an octave lower than for IRN(+). This is reflected in a first peak at twice the delay in the ACF of the waveform for IRN(−). In contrast, for identical delays, the ACF of the envelope for both IRN(−) and IRN(+) is the same. Thus the use of IRN allows the distinction between envelope - or fine-structure sensitivity. Recordings were made from 135 single units (BFs <5 kHz) in the DCN of the anesthetized guinea pig using IRN with delays ranging from 1 to 32 ms. In our sample 42% were sensitive to the periodicity of IRN(+) and were tuned to a particular delay in their first-order interspike interval histograms (ISIHs). This tuning was highly correlated with their response to white noise. Most units with best frequencies (BFs) <500 Hz show a different all-order ISIH for IRN(+) and IRN(−), which corresponds to the perceived pitch difference, whereas units with higher BFs show a similar response to IRN(+) and IRN(−). The results indicate that low-frequency units (BF <500 Hz) in the DCN may be involved in the representation of the waveform fine structure, although units with BFs >500 Hz are able to encode only the envelope periodicity of broadband IRN in their temporal discharge characteristics.
Directional Asymmetry During Combined Saccade–Vergence Movements
Authors: Kumar Arun N. , Han Yanning , Dell'osso Louis F. , Durand Dominique M. , Leigh R. John
Published: April 2005

We investigated relationships between saccadic and vergence components of gaze shifts as 10 human subjects switched visual fixation between targets aligned in the midsagittal plane that lay in different vertical directions and at different distances. When fixation was shifted between a higher distant target and a lower near target, peak convergence velocity followed peak vertical saccadic velocity by a median interval of 12 ms. However, when fixation was shifted between a lower distant target and a higher near target, peak convergence velocity followed peak vertical saccadic velocity by a median interval of 76 ms. For the 2 stimulus arrangements, the median intervals by which peak divergence velocity followed the peak vertical saccadic velocity were 4 and 20 ms, respectively. The dissociation interval between the peak velocities of convergence and upward saccades increased with vertical saccade size, required convergence angle, and elevation of the endpoint of the movement. Velocity waveforms of vergence responses were more skewed when peak velocity was closely associated with saccadic peak velocity than when the vergence responses were delayed. Convergence peak velocities did not vary in any consistent pattern, but divergence peak velocities were generally smaller with responses that were delayed. Vergence movements were accompanied by small, high-frequency conjugate oscillations, suggesting that omnipause neurons were inhibited for both types of responses. In conclusion, the present findings indicate that the dynamic properties of horizontal vergence movements depend on the direction and timing of vertical saccades; these findings suggest experimental tests for current models of saccade–vergence interaction.
In Vivo Calcium Imaging of Circuit Activity in Cerebellar Cortex
Authors: Sullivan Megan R. , Nimmerjahn Axel , Sarkisov Dmitry V. , Helmchen Fritjof , Wang Samuel S.-H.
Published: April 2005

In vivo two-photon calcium imaging provides the opportunity to monitor activity in multiple components of neural circuitry at once. Here we report the use of bulk-loading of fluorescent calcium indicators to record from axons, dendrites, and neuronal cell bodies in cerebellar cortex in vivo. In cerebellar folium crus IIa of anesthetized rats, we imaged the labeled molecular layer and identified all major cellular structures: Purkinje cells, interneurons, parallel fibers, and Bergmann glia. Using extracellular stimuli we evoked calcium transients corresponding to parallel fiber beam activity. This beam activity triggered prolonged calcium transients in interneurons, consistent with in vitro evidence for synaptic activation of N-methyl-d-aspartate receptors via glutamate spillover. We also observed spontaneous calcium transients in Purkinje cell dendrites that were identified as climbing-fiber-evoked calcium spikes by their size, time course, and sensitivity to AMPA receptor antagonist. Two-photon calcium imaging of bulk-loaded cerebellar cortex is thus well suited to optically monitor synaptic processing in the intact cerebellum.
Microsecond Precision of Phase Delay in the Auditory System of the Barn Owl
Authors: Wagner Hermann , Brill Sandra , Kempter Richard , Carr Catherine E.
Published: April 2005

The auditory system encodes time with sub-millisecond accuracy. To shed new light on the basic mechanism underlying this precise temporal neuronal coding, we analyzed the neurophonic potential, a characteristic multiunit response, in the barn owl's nucleus laminaris. We report here that the relative time measure of phase delay is robust against changes in sound level, with a precision sharper than 20 μs. Absolute measures of delay, such as group delay or signal-front delay, had much greater temporal jitter, for example due to their strong dependence on sound level. Our findings support the hypothesis that phase delay underlies the sub-millisecond precision of the representation of interaural time difference needed for sound localization.
Detection of large deletions in the LDL receptor gene with quantitative PCR methods
Authors: Damgaard Dorte , Nissen Peter H , Jensen Lillian G , Nielsen Gitte G , Stenderup Anette , Larsen Mogens L , Faergeman Ole
Published: April 2005

Background

Familial Hypercholesterolemia (FH) is a common genetic disease and at the molecular level most often due to mutations in the LDL receptor gene. In genetically heterogeneous populations, major structural rearrangements account for about 5% of patients with LDL receptor gene mutations.

Methods

In this study we tested the ability of two different quantitative PCR methods, i.e. Real-Time PCR and Multiplex Ligation-Dependent Probe Amplification (MLPA), to detect deletions in the LDL receptor gene. We also reassessed the contribution of major structural rearrangements to the mutational spectrum of the LDL receptor gene in Denmark.

Results

With both methods it was possible to discriminate between one and two copies of the LDL receptor gene exon 5, but the MLPA method was cheaper, and it was far more accurate and precise than Real-Time PCR. In five of 318 patients with an FH phenotype, MLPA analysis revealed five different deletions in the LDL receptor gene.

Conclusion

The MLPA method was accurate, precise and at the same time effective in screening a large number of FH patients for large deletions in the LDL receptor gene.
Development and preliminary evaluation of the VPS ReplaySuite: a virtual double-headed microscope for pathology
Authors: Johnston Dan J , Costello Sean P , Dervan Peter A , O'Shea Daniel G
Published: April 2005

Background

Advances in computing and telecommunications have resulted in the availability of a range of online tools for use in pathology training and quality assurance. The majority focus on either enabling pathologists to examine and diagnose cases, or providing image archives that serve as reference material. Limited emphasis has been placed on analysing the diagnostic process used by pathologists to reach a diagnosis and using this as a resource for improving diagnostic performance.

Methods

The ReplaySuite is an online pathology software tool that presents archived virtual slide examinations to pathologists in an accessible video-like format, similar to observing examinations with a double-headed microscope. Delivered through a customised web browser, it utilises PHP (Hypertext PreProcessor) to interact with a remote database and retrieve data describing virtual slide examinations, performed using the Virtual Pathology Slide (VPS).

To demonstrate the technology and conduct a preliminary evaluation of pathologists opinions on its potential application in pathology training and quality assurance, 70 pathologists were invited to use the application to review their own and other pathologists examinations of 10 needle-core breast biopsies and complete an electronic survey. 9 pathologists participated, and all subsequently completed an exit survey.

Results

Of those who replayed an examination by another pathologist, 83.3% (5/6) agreed that replays provided an insight into the examining pathologists diagnosis and 33.3% (2/6) reconsidered their own diagnosis for at least one case. Of those who reconsidered their original diagnosis, all re-classified either concordant with group consensus or original glass slide diagnosis. 77.7% (7/9) of all participants, and all 3 participants who replayed more than 10 examinations stated the ReplaySuite to be of some or great benefit in pathology training and quality assurance.

Conclusion

Participants conclude the ReplaySuite to be of some or of great potential benefit to pathology training and quality assurance and consider the ReplaySuite to be beneficial in evaluating the diagnostic trace of an examination. The ReplaySuite removes temporal and spatial issues that surround the use of double-headed microscopes by allowing examinations to be reviewed at different times and in different locations to the original examination. While the evaluation set was limited and potentially subject to bias, the response of participants was favourable. Further work is planned to determine whether use of the ReplaySuite can result in improved diagnostic ability.
Stereophysicochemical variability plots highlight conserved antigenic areas in Flaviviruses
Authors: Schein Catherine H , Zhou Bin , Braun Werner
Published: April 2005

Background

Flaviviruses, which include Dengue (DV) and West Nile (WN), mutate in response to immune system pressure. Identifying escape mutants, variant progeny that replicate in the presence of neutralizing antibodies, is a common way to identify functionally important residues of viral proteins. However, the mutations typically occur at variable positions on the viral surface that are not essential for viral replication. Methods are needed to determine the true targets of the neutralizing antibodies.

Results

Stereophysicochemical variability plots (SVPs), 3-D images of protein structures colored according to variability, as determined by our PCPMer program, were used to visualize residues conserved in theirphysicalchemicalproperties (PCPs) near escape mutant positions. The analysis showed 1) that escape mutations in the flavivirus envelope protein are variable residues by our criteria and 2) two escape mutants found at the same position in many flaviviruses sit above clusters of conserved residues from different regions of the linear sequence. Conservation patterns in T-cell epitopes in the NS3- protease suggest a similar mechanism of immune system evasion.

Conclusion

The SVPs add another dimension to structurally defining the binding sites of neutralizing antibodies. They provide a useful aid for determining antigenically important regions and designing vaccines.
Prevention of mobile phone induced skin tissue changes by melatonin in rat: an experimental study
Authors: Ozguner Fehmi , Aydin Gulsen , Mollaoglu Hakan , Gökalp Osman , Koyu Ahmet , Cesur Gokhan
Published: April 2005

Most of the mobile phones in Turkey emit 900 MHz radiation which is mainly absorbed by the skin and, to a lesser extent, muscle. The aim of this study was to investigate the effects the 900 MHz electromagnetic irradiation emitted by these devices on the induction of histopathologic changes in skin and the effect of melatonin (Mel) on any of these changes. Thirty male Wistar-Albino rats were used in the study. The experimental groups were composed of: a nontreated control group, an irradiated group (IR) without Mel and an irradiated with Mel treatment group (IR + Mel). 900 MHz radiation was applied to IR group for 10 days (30 min/day). The IR + Mel group received 10 mg/kg per day melatonin in tap water for 10 days before irradiation. At the end of the tenth day, the skin graft was excized from the thoraco-abdominal area. Histopathologic changes in skin were analyzed. In the IR group, increased thickness of stratum corneum, atrophy of epidermis, papillamatosis, basal cell proliferation, increased granular cell layer (hypergranulosis) in epidermis and capillary proliferation, impairment in collagen tissue distribution and separation of collagen bundles in dermis were all observed compared to the control group. Most of these changes, except hypergranulosis, were prevented with melatonin treatment. In conclusion, exposure to 900 MHz radiation emitted by mobile phones caused mild skin changes. Furthermore, melatonin treatment can reduce these changes and may have a beneficial effect to prevent 900 MHz mobile phone-induced rat skin changes.
Sirenomelia inBmp7andTsgcompound mutant mice:requirement for Bmp signaling in the development of ventral posterior mesoderm
Authors: Zakin Lise , Reversade Bruno , Kuroda Hiroki , Lyons Karen M. , De Robertis Eddy M.
Published: April 2005

Sirenomelia or mermaid-like phenotype is one of the principal human congenital malformations that can be traced back to the stage of gastrulation. Sirenomelia is characterized by the fusion of the two hindlimbs into a single one. In the mouse, sirens have been observed in crosses between specific strains and as the consequence of mutations that increase retinoic acid levels. We report that the loss of bone morphogenetic protein 7 (Bmp7) in combination with a half dose or complete loss of twisted gastrulation (Tsg)causes sirenomelia in the mouse. Tsg is a Bmp- and chordin-binding protein that has multiple effects on Bmp metabolism in the extracellular space; Bmp7 is one of many Bmps and is shown here to bind to Tsg. In Xenopus,co-injection of Tsg and Bmp7 morpholino oligonucleotides (MO) has a synergistic effect, greatly inhibiting formation of ventral mesoderm and ventral fin tissue. In the mouse, molecular marker studies indicate that the sirenomelia phenotype is associated with a defect in the formation of ventroposterior mesoderm. These experiments demonstrate that dorsoventral patterning of the mouse posterior mesoderm is regulated by Bmp signaling, as is the case in other vertebrates. Sirens result from a fusion of the hindlimb buds caused by a defect in the formation of ventral mesoderm.
crossveinless-cis a RhoGAP required for actin reorganisation during morphogenesis
Authors: Denholm Barry , Brown Stephen , Ray Robert P. , Ruiz-Gómez Mar , Skaer Helen , Hombría James Castelli-Gair
Published: April 2005

Members of the Rho family of small GTPases are required for many of the morphogenetic processes required to shape the animal body. The activity of this family is regulated in part by a class of proteins known as RhoGTPase Activating Proteins (RhoGAPs) that catalyse the conversion of RhoGTPases to their inactive state. In our search for genes that regulate Drosophila morphogenesis, we have isolated several lethal alleles of crossveinless-c (cv-c). Molecular characterisation reveals that cv-c encodes the RhoGAP protein RhoGAP88C. During embryonic development, cv-c is expressed in tissues undergoing morphogenetic movements; phenotypic analysis of the mutants reveals defects in the morphogenesis of these tissues. Genetic interactions between cv-c and RhoGTPase mutants indicate that Rho1, Rac1 and Rac2 are substrates for Cv-c,and suggest that the substrate specificity might be regulated in a tissue-dependent manner. In the absence of cv-c activity,tubulogenesis in the renal or Malpighian tubules fails and they collapse into a cyst-like sack. Further analysis of the role of cv-c in the Malpighian tubules demonstrates that its activity is required to regulate the reorganisation of the actin cytoskeleton during the process of convergent extension. In addition, overexpression of cv-c in the developing tubules gives rise to actin-associated membrane extensions. Thus, Cv-c function is required in tissues actively undergoing morphogenesis, and we propose that its role is to regulate RhoGTPase activity to promote the coordinated organisation of the actin cytoskeleton, possibly by stabilising plasma membrane/actin cytoskeleton interactions.
Evaluation of the Serodia Treponema pallidum particle agglutination, the Murex Syphilis ICE and the Enzywell TP tests for serodiagnosis of syphilis
Authors: Aktas G , Young H , Moyes A , Badur S
Published: April 2005

We evaluated the Treponema pallidum haemagglutination assay (TPHA), a treponemal test, with three other treponemal tests, the Serodia T. pallidum particle agglutination assay, the Murex Syphilis ICE IgG + IgM enzyme immunoassay (EIA) and the Enzywell TP IgG + M EIA (a new rapid EIA) for use in conjunction with the rapid plasma reagin test (RPR), a non-treponemal test, for serodiagnosis of syphilis. In all, 124 serum samples were found reactive with RPR and/or TPHA after testing by the routine laboratory protocol. Twenty-three (18.5%) of them were positive only by RPR test and were evaluated as biologically false-positive, 16 were positive only by the TPHA and 84 by both the RPR and TPHA tests; one sample was non-specific (heterophile reaction) in the TPHA.

Agreements of the TPHA with the Serodia TPPA, the Murex Syphilis ICE and the Enzywell TP tests were 96.7%, 100% and 99.1%, respectively.

We conclude that each one of the tests, the Serodia TPPA, the Murex Syphilis ICE and the Enzywell TP, is an appropriate substitute for screening for serodiagnosis of syphilis.
Using chlamydia positivity to estimate prevalence: evidence from the Chlamydia Screening Pilot in England
Authors: LaMontagne D S , Fenton K A , Pimenta J M , Catchpole M , Rogers P A , Randall S , Hewitt W G , Mallinson H , Underhill G S , McLean L , Gleave T , Harindra V , Ghosh A K , Tobin J M
Published: April 2005

Studies have suggested that positivity can be used to estimate the prevalence of Chlamydia trachomatis in large-scale chlamydia screening programmes. A recent pilot of opportunistic screening in England estimated that the prevalence among 16–24-year-old women in Portsmouth and Wirral was 9.8% and 11.2%, respectively. This study assessed the continued validity of positivity as an approximate for prevalence. We re-analysed data from the Chlamydia Screening Pilot to estimate positivity, calculated as total positive tests divided by total tests, and compared these estimates with the previously reported prevalence, measured as the number of women testing positive divided by the total number of women screened. Overall positivity was 9.4% in Portsmouth and 11.0% in the Wirral; these estimates were not statistically different from prevalence, regardless of health-care setting, age group or symptoms. We conclude that positivity can be used as a proxy for prevalence.
Developing and Assembling the Law School Admission Test
Authors: Armstrong Ronald , Belov Dmitry , Weissman Alexander
Published: April 2005

Standardized tests are useful for assessing an individual’s potential to succeed in various endeavors. In addition, institutions use them to measure student achievement and to measure the efficacy of pedagogical approaches. Operations research tools can help those developing rigorous standardized tests. Our mixed-integer program (MIP) provides a model for assembling forms for the Law School Admission Test (LSAT). Since 2002, our LSAT assembler—software we developed using a Monte Carlo approach—has produced test forms meeting all specifications. This software has saved thousands of hours of personnel time.
Book Reviews
Authors: Lev Benjamin
Published: April 2005

The range of books reviewed is wide, covering theory and applications in operations research, statistics, management science, econometrics, mathematics, computers, and information systems (no software is reviewed). In addition, we include books in other fields that emphasize technical applications. Publishers who wish to have their books reviewed should send them to Professor Benjamin Lev. We list the books received; not all books received can be reviewed because space is limited. Those who would like to review books are urged to send me their names, addresses, and specific areas of expertise. We commission all reviews and do not accept unsolicited book reviews. Readers are encouraged to suggest books that might be reviewed or to ask publishers to send me copies of such books.

The authors or editors of the books reviewed in this issue are Benjamin F. Hobbs, Michael H. Rothkopf, Richard P. O’Neill, Hung-Po Chao, David R. Laube, Raymond F. Zammuto, Douglas Long, Charles A. Micchelli, Gianni Di Pillo, and Almerico Murli.
A Florida County Locates Disaster Recovery Centers
Authors: Dekle Jamie , Lavieri Mariel S. , Martin Erica , Emir-Farinas Hülya , Francis Richard L.
Published: April 2005

In 2001, the Federal Emergency Management Agency (FEMA) required every Florida county to identify potential locations of disaster recovery centers (DRCs). The DRCs are to be opened and staffed by FEMA personnel, subsequent to any declared disaster. The Emergency Management Division of the Alachua County Department of Fire/Rescue Services sponsored a project to identify potential DRC sites. The project team used a mathematical analysis tool called the covering location model in a two-stage approach to find, recommend, and have accepted DRC locations. The “stage 1” approach gave three idealized DRC locations requiring each residence in the county to be within 20 miles of the closest DRC. Next, the team relaxed the 20-mile requirement and identified locations close to the “stage 1” locations that also satisfied evaluation criteria not included in stage 1. The “stage 2” results provided significant improvements to the original FEMA location criteria, while maintaining acceptable travel distances to the nearest DRC.
Competition Among Sellers in Online Exchanges
Authors: Bandyopadhyay Subhajyoti , Barron John M. , Chaturvedi Alok R.
Published: April 2005

With the advent of the Internet, and the minimal information technology requirements of a trading partner to join an exchange, the number of sellers who can qualify and participate in online exchanges is greatly increased. We model the competition between two sellers with different unit costs and production capacities responding to a buyer demand. The resulting mixed-strategy equilibrium shows that one of the sellers has a normal high price with random sales, while the other seller continuously randomizes its prices. It also brings out the inherent advantages that sellers with lower marginal costs or higher capacities have in joining these exchanges, and provides a theoretical basis for understanding the relative advantages of various types of sellers in such exchanges.
A Distributed Decision-Making Structure for Dynamic Resource Allocation Using Nonlinear Functional Approximations
Authors: Topaloglu Huseyin , Powell Warren B.
Published: April 2005

This paper proposes a distributed solution approach to a certain class of dynamic resource allocation problems and develops a dynamic programming-based multiagent decision-making, learning, and communication mechanism. In the class of dynamic resource allocation problems we consider, a set of reusable resources of different types has to be assigned to tasks that arrive randomly over time. The assignment of a resource to a task removes the task from the system, modifies the state of the resource, and generates a contribution. We build a decision-making scheme where the decisions regarding the resources in different sets of states are made by different agents. We explain how to coordinate the actions of different agents using nonlinear functional approximations, and show that in a distributed setting, nonlinear approximations produce sequences of min-cost network flow problems that naturally yield integer solutions. We also experimentally compare the performances of the centralized and distributed solution strategies.
Pricing and Design of Differentiated Services: Approximate Analysis and Structural Insights
Authors: Maglaras Constantinos , Zeevi Assaf
Published: April 2005

We consider a model of a service system that delivers two nonsubstitutable services to a market of heterogenous users. The first service is delivered subject to a “guaranteed” (G) processing rate, and the second is a “best-effort” (BE) type service in which residual capacity not allocated to the guaranteed class is shared among BE users. Users, in turn, are sensitive to both price and congestion-related effects. The service provider’s objective is to optimally design the system so as to extract maximum revenues. The design variables in this problem consist of a pair of static prices for the two services, a policy that controls admission of G users into the system, and the mechanism by which users are informed of the state of congestion in the system. Because these objectives are difficult to address using exact analysis, we pursue approximations that are tractable and lead to structural insights. Specifically, we first solve a deterministic relaxation of the original objective to obtain a “fluid-optimal” solution that is subsequently evaluated and refined to account for stochastic fluctuations. Using diffusion limits, we derive approximations that yield the following structural results: (1) pricing rules derived from the deterministic analysis are “almost” optimal, (2) the optimal operational regime for the system is close to heavy traffic, and (3) real-time congestion notification results in increased revenues. Numerical results illustrate the accuracy of the proposed approximations and validate the aforementioned structural insights.
Hypomethylation in the promoter region of POMC gene correlates with ectopic overexpression in thymic carcinoids
Authors: Ye Lei , Li Xiaoying , Kong Xiangyin , Wang Weiqing , Bi Yufang , Hu Landian , Cui Bin , Li Xi , Ning Guang
Published: April 2005

The ectopic ACTH syndrome is caused by abnormal expression of the POMC gene product arising from non-pituitary tumors in response to the ectopic activation of the pituitary-specific promoter of this gene. It has been proved that methylation of the CpG island in the promoter region is associated with silencing of some genes. Using bisulphite sequencing, we identified hypermethylation in the 5′ promoter region of the POMC gene in three normal thymuses and one large cell lung cancer, and hypomethylation in five thymic carcinoid tumors resected from patients with ectopic ACTH syndrome. The region undergoing hypermethylation was narrowed to coordinates −417 to −260 of the POMC promoter. Furthermore, we observed that the levels of POMC expression correlated with the methylation density at −417 to −260 bp across the E2 transcription factor binding region of the POMC promoter. It is concluded that hypomethylation of the POMC promoter in thymic carcinoids correlates with POMC overexpression and the ectopic ACTH syndrome.