bluuebunny/crossref_metadata_2025_split huggingface dataset:
Disclosure of HIV‐Positive Status to Latino Gay Men's Social Networks
Authors: Zea María Cecilia , Reisen Carol A. , Poppen Paul J. , Echeverry John J. , Bianchi Fernanda T. 
Published: February 2004

AbstractThis study explored disclosure of serostatus in a sample of 155 HIV‐positive Latino gay men from New York City and Washington, DC. We examined rates of disclosure to different members of the social network: mothers, fathers, close friends, and primary sexual partners. There were high rates of disclosure of HIV‐positive serostatus to main partners and closest friends and lower rates to fathers and mothers. We examined the role of 3 contextual target‐dependent factors (emotional closeness to target, anticipated reactions from target, and target's knowledge of sexual orientation), as well as acculturation and time since diagnosis. Three separate logistic regression models were performed to predict disclosure of HIV‐positive status to 3 targets: mothers, fathers, and closest friends. We found that disclosure was not a generalized tendency, but rather different factors were influential depending on the target. Whether the target was aware of participant's sexual orientation was associated with disclosure in all 3 models. Greater emotional closeness also predicted disclosure to mother and father; greater U.S. acculturation was associated with disclosure to father and marginally to mother. A longer time since diagnosis was associated with disclosure to the closest friend. These findings highlight the importance of taking into account roles and relationships, and their effect on disclosure.
Solar ultraviolet radiation and total ozone, as derived from satellite and ground‐based instrumentation
Authors: Varotsos C. 
Published: February 2004

Daily broad‐band measurements of solar ultraviolet radiation reaching the ground at Athens, Greece (38°N, 24°E) during 1989–1991 in conjunction with daily total ozone measurements deduced from satellite and ground‐based instrumentation were used to investigate their association. Furthermore, employing a parametric model, the spectral and broad‐band solar ultraviolet radiation for the period 1979–1991 were calculated considering the total ozone values, derived from the satellite Nimbus‐7.Total ozone reductions of 2.5% during summertime and 7% during wintertime per decade, cause an increase in erythemally active UV‐B irradiance of 5% and 14% respectively.
A 27‐month periodicity in the low latitude geomagnetic field and its connection to the stratospheric QBO
Authors: Olsen Nils 
Published: February 2004

Geomagnetic daily variations are produced at a height of about 100 to 130 km due to dynamo action of thermospheric winds in combination with the ionospheric conductivity. They are influenced by longterm variability of thermospheric dynamics and are used as tool for investigating a QBO in thermospheric winds.Power spectrum analysis has been applied to monthly means of the daily range of the geomagnetic field. In addition to an annual modulation (and subharmonics) there is clear evidence for a sharp peak at about 27 months in the H‐component at low‐latitude observatories (ΔH ≈ 0.5 nT). At single observatories, statistical significance is at the 99% confidence level, squared coherency between distant observatories is highly significant, too. However, there is no global modulation of the Sq current system because (1) the D‐component contain no 27‐month periodicity, and (2) the oscillation is not present at mid‐latitude observatories.In order to explain the observations, a 27‐month oscillation in the low‐latitude prevailing zonal winds with an amplitude of few m/s at a height of about 100‐130 km is postulated. Squared Coherency between geomagnetic variations and prevailing winds in the equatorial stratosphere is significant at the 95%‐level.
Line strength measurements of trans‐HONO near 1255 cm−1 by tunable diode laser spectrometry
Authors: Becker K. H. , Kleffmann J. , Kurtenbach R. , Wiesen P. , Febo A. , Gherardi M. , Sparapani R. 
Published: February 2004

Infrared absorption spectra and line strengths in the ν3 H‐O‐N bending mode of trans‐HONO near 1255 cm−1 have been measured with a tunable diode laser spectrometer. High purity HONO (>98%) was produced by a reaction of gaseous HCl with solid NaNO2. Absolute HONO concentrations were determined either by ion chromatography or by a NOx chemiluminescence analyser.Line strengths of the strongest lines observed were found to be in the range of (7–12) × 10−21 cm under near Doppler‐limited conditions and differ significantly from literature data. In addition, the dependence of the line width on the total air pressure was investigated in the range 0.–25 Torr, and also the possibility of measuring HONO atmospheric mixing ratios with a tunable diode laser was assessed.
Stochastic variability at the air‐sea interface on decadal timescales
Authors: Power Scott B. , Tseitkin F. , Dix M. , Kleeman R. , Colman R. , Holland D. 
Published: February 2004

Multiple integrations of an atmospheric general circulation model (AGCM) exhibit differences in the decadal mean of the surface heat flux, Q. The differences (typically 2–3 Wm−2) can be as large as 10 Wm−2 in places, which are shown to produce sea‐surface temperature (SST) changes up to approximately 0.5°C in a hybrid coupled atmosphere/ocean/sea‐ice model or HCM. This underscores a significant mechanism by which long‐lived SST anomalies can arise, independent of any internal ocean variability, for which there is very little predictive capability. Consequently, AGCM integrations using prescribed SSTs provide upper bounds on the predictability of atmospheric variability. The HCM is used to estimate the magnitude of the drift in the climatology of coupled models if flux adjustments are based on AGCM integrations of decadal duration.The random interannual fluctuations in Q averaged over the ocean are most closely associated with fluctuations in surface latent heating and long wave radiation to space. The same fluctuations are not associated with land surface variability.The impact of variability in other fluxes on SST in the HCM was also analysed. Changes due to wind‐stress were approximately half those due to heating, while changes due to freshwater forcing were relatively unimportant except at polar latitudes.
210Po and 210Pb disequilibrium in the hydrothermal vent fluids and chimney deposits from Juan de Fuca Ridge
Authors: Hussain N. , Church T. M. , Luther G. W. , Moore W. S. 
Published: February 2004

Significantly deficient 210Po/210Pb activity ratios (0.14±0.14) are measured in the hydrothermal vent fluids collected from Juan de Fuca Ridge. Chimney deposits generally showed <5 dpm of excess 210Po. However, one sample from the outermost layer of a sealed spire yielded >1200 dpm g−1 of excess 210Po.If the observed 210Po‐210Pb disequilibrium in vent fluids is a result of 210Po removal by the precipitates, residence time of polonium with respect to its irreversible removal from hot fluids is estimated to be of the order of a few minutes. Alternatively, if the disequilibrium is a result of an insufficient growth of 210Po from in‐situ210Pb following heating, the residence time of hot fluids within the hydrothermal system can be shown to be less than 30 days, which is considerably lower than previously reported values.
Dicing with earthquakes
Authors: Burton Paul W. 
Published: February 2004

The VAN group have been publicizing claims to be predicting earthquakes since 1981. Their predictions of two basic parameters of earthquakes, magnitude and location, are very loosely constrained. Most VAN magnitude predictions are below 5.7 Ms, with a tolerance of ±0.7 Ms. The uncertainty range spanned by a predicted magnitude is so enveloping that such forecasts cannot be viewed as plainly successful In terms of VAN's claims to spatial resolution, these, if successful, might constrain the linear dimension of the source region of a magnitude 8.0 Ms earthquake but do not adequately constrain a magnitude as large as 7.5 Ms.Not only do VAN need to refine the tolerances in their magnitude and location predictions before careful judgements can be made, but it is also necessary to provide an unambiguous statement of the prediction hypothesis used in relation to a pre‐published and communally archived dataset of complete seismic electric signal occurrences similar to Seismological Station Bulletins.
Simulated annealing two‐point ray tracing
Authors: Velis Danilo R. , Ulrych Tadeusz J. 
Published: February 2004

We present a new method for solving the two‐point seismic ray tracing problem based on Fermat's principle. The algorithm overcomes some well known difficulties that arise in standard ray shooting and bending methods. Problems related to: (1) the selection of new take‐off angles, and (2) local minima in multipathing cases, are overcome by using an efficient simulated annealing (SA) algorithm. At each iteration, the ray is propagated from the source by solving a standard initial value problem. The last portion of the raypath is then forced to pass through the receiver. Using SA, the total traveltime is then globally minimized by obtaining the initial conditions that produce the absolute minimum path.The procedure is suitable for tracing rays through 2D complex structures, although it can be extended to deal with 3D velocity media. Not only direct waves, but also reflected and head‐waves can be incorporated in the scheme. One important advantage is its simplicity, in as much as any available or user‐preferred initial value solver system can be used. A number of clarifying examples of multipathing in 2D media are examined.
Glacial to interglacial surface nutrient variations of Bering Deep Basins recorded by δ13C and δ15N of sedimentary organic matter
Authors: Nakatsuka Takeshi , Watanabe Kazuki , Handa Nobuhiko , Matsumoto Eiji , Wada Eitaro 
Published: February 2004

Stable carbon and nitrogen isotopic ratios (δ13C and δ15N) of organic matter were measured in three sediment cores from deep basins of the Bering Sea to investigate past changes in surface nutrient conditions. For surface water reconstructions, hemipelagic layers in the cores were distinguished from turbidite layers (on the basis of their sedimentary structures and 14C ages) and analyzed for isotopic studies. Although δ13C profiles may have been affected by diagenesis, both δ15N and δ13C values showed common positive anomalies during the last deglaciation. We explain these anomalies as reflecting suppressed vertical mixing and low nutrient concentrations in surface waters caused by injection of meltwater from alpine glaciers around the Bering Sea.Appendix tables are available with entire article on microfiche. Order from American Geophysical Union, 2000 Florida Avenue, N.W., Washington , DC 20009. Document P95‐003; $2.50. Payment must accompany order.
Reply to “The VAN earthquake predictions,” by D. A. Rhoades and F. F. Evison
Authors: Varotsos P. , Lazaridou M. 
Published: February 2004

Rhoades and Evison [1996] indicated a technical flaw in the procedure of Mulargia and Gasperini [1992] and also made many useful remarks and fundamental suggestions on the correct way for performing a statistical evaluation of an earthquake prediction method. We think that these suggestions should be carefully followed by statisticians in the future.However, we do not agree with Rhoades and Evison's [1996] opinion that objective tests of the performance of the VAN‐method, using independent data, cannot begin until the method and the null hypothesis have been fully formulated. In our opinion the main question in the present debate is whether our predictions can be ascribed to chance. Such a test has already been carried out in this issue by Aceves et al. [1996], although they make it clear that they have tested the significance of our predictions and not the overall success of our method.
Diffraction of long period Rayleigh waves by a slab: effects of mode coupling
Authors: Lognonné Philippe , Clévédé Eric 
Published: February 2004

We compute seismograms of the fundamental Rayleigh waves propagating through a slab structure, with either a lateral variation in seismic velocities, or in attenuation. At periods of 100 sec, we show that the phase delay is strongly reduced by the surface waves Fresnel zone, and that coupling must be considered far along the dispersion branch, up to at least ℓ±25. Limiting the coupling to fewer modes produces a signal associated to a ghost structure at the antipode of the slab. We also show that the amplitude perturbations produced by the diffraction and the attenuation of the slab are comparable in size.Future waveform studies, especially those associated to global waveform inversions, must then carefully consider these effects.
Multiple receiver wind profiling techniques for the boundary layer in the presence of hydro‐meteors
Authors: Van Baelen Joel , Hirsch Lutz , Prada Claire 
Published: February 2004

A UHF boundary layer wind profiler has been operated in a multiple receiver mode. The data sets collected are used to estimate the horizontal wind using different multiple receiver analysis techniques performed in the time and frequency domains. Those results are also compared with simultaneous Doppler beam swinging measurements.The particularity of the data sets used for this inter‐comparison is that they were recorded while hydro‐meteors were present in the boundary layer. The large mean fall speed and the broad fall velocity distribution of rain drops causes a much more rapid decay of diffraction patterns than in the case of scattering by snow flakes or micro turbulence. Therefore, analysis methods which do not account for the effect of the decay of the diffraction patterns show an over‐estimation of the wind velocity, and do so in a different way whether snow or rain is present. To the contrary, algorithms that account for the effect of diffraction pattern decay appear to reasonably estimate the actual horizontal wind and compare well with the Doppler measurements.
Ground‐based measurements of tropospheric and stratospheric BrO at Arrival Heights, Antarctica
Authors: Kreher K. , Johnston P. V. , Wood S. W. , Nardi B. , Platt U. 
Published: February 2004

Ground‐based measurements of BrO slant column densities (SCDs) were performed using zenith sky DOAS (Differential Optical Absorption Spectroscopy) during autumn (February to May) and spring (August to October) of 1995 at Arrival Heights (77.8°S, 166.7°E).In both August and September, single episodes of sudden large BrO column enhancement (of magnitude 3.5 and 3.2 × 1014 molec. cm−2 respectively) were observed. The episode in August did not coincide with changes of other stratospheric parameters (OClO, NO2 and temperature). Furthermore, the diurnal variation in the SCD during these events was indicative of a tropospheric rather than a stratospheric absorber. The tropospheric BrO mixing ratios deduced from the data are similar to those observed by ground‐based measurements in the Arctic boundary layer (∼30 ppt).Simultaneous balloon soundings, one during each of the two events, showed statistically significant (2 σ) tropospheric ozone depletion between 0.5 and 2 km in August and 1.5 and 2.8 km in September. Our results strongly suggest that halogen catalysed boundary layer ozone depletion not only occurs in the Arctic but also in Antarctica. This has the implication that Arctic Haze and anthropogenic influence is unlikely as a cause for this phenomenon.
Lateral asthenospheric viscosity variations and postglacial rebound: A case study for the Barents Sea
Authors: Kaufmann Georg , Wu Patrick 
Published: February 2004

The effect of lateral asthenospheric viscosity variations on observable signatures related to postglacial rebound in the Barents Sea is studied. Using a finite‐element approach to discretize the problem, a comparison between a laterally homogeneous reference earth model and a laterally heterogeneous earth model is performed.The results indicate that a change in asthenospheric viscosity of about three orders of magnitude influences predictions of land uplift up to 10–20 m, present‐day velocities up to 0.5–1.5 mm/a, and present‐day gravity anomalies up to 0.4–0.8 mGal in the northwestern part of the Barents Sea region.
Recurrent erysipelas: risk factors
Authors: Pavlotsky Felix , Amrani Shalom , Trau Henry 
Published: February 2004

Summary Background: Several systemic and regional risk factors have been described for erysipelas. However, those predisposing for recurrent episodes are not well defined. Materials and methods: We performed a retrospective analysis of 574 patients hospitalized in our institution during a 3 year period. The analysis included demographic, epidemiologic, and medical chart review data with special attention to background disorders. The patients with single and recurrent episodes of erysipelas were compared. Results: The recurrent cases occurred mainly in the lower limb with several risk factors that were statistically more common than in the single episode group including overweight, venous insufficiency, lymphedema, tinea pedis, and previous regional surgical intervention or trauma. Conclusions: Patients with erysipelas, especially when it involves the lower limb, should be instructed to reduce weight, control venous insufficiency and/or lymphedema and to emphasize prevention and treatment of tinea pedis. The role of prophylactic antibiotics requires further study.
Major determinants of optic nerve head topographic characteristics in a normal Turkish population
Authors: Akar Yusuf , Orhan Mehmet , İrkeç Murat , Karaag˘aoglu Ergun 
Published: February 2004

Abstract Aim: To determine the factors affecting the topographic characteristics of the optic nerve head in a normal Turkish population. Methods: A cross‐sectional study was performed on the optic nerve head of the right eyes of 613 healthy subjects of both sexes aged 11−77 years using a confocal scanning laser ophthalmoscope. The study population was divided into three groups (<20 years, 20−50 years, and>50 years) to evaluate age‐related changes in the optic nerve head topography. A total of 15 variables were determined. Statistical analysis was performed using Student's t‐test, anova, Tukey HSD test, linear regression analysis and Pearson's correlation coefficient. Results: Four eyes were excluded from the study due to poor image quality. There were 307 female subjects and 302 male subjects. The mean age of the subjects was 42.1 ± 15.1 years. The mean optic disc areas were 1.99 ± 0.45 mm2 and 1.97 ± 0.41 mm2 for male and female subjects, respectively. The disc area of the subjects ranged between 1.01 and 4.19 mm2. Disc area was found to be associated with all of the optic nerve head variables studied, and was also found to be significantly increased with advancing age (P < 0.05). The only variable that showed a sex‐related difference was neuroretinal rim volume, which was found to be higher in female subjects in all cases. Conclusion: Optic disc area was found to be the main determinant of the optic nerve head topography in a normal population. Optic disc area was found to be significantly increased with ageing in a normal population. These acquired changes to the optic disc could suggest stretching of the scleral ring, which may highlight the role of advancing age on the pathogenesis of glaucomatous optic neuropathy.
Outcome of consecutive trabeculectomy
Authors: Zalish Miriam , Oron Yoram , Geyer Orna 
Published: February 2004

Abstract Purpose: To establish a criterion for success of primary phakic trabeculectomy in the second eye of the same patient, using the first operated eye as a predictor for the surgical outcome. Methods: The outcome of primary phakic trabeculectomy was retrospectively compared in both eyes of 23 patients. Sixteen patients were treated with antimetabolites and seven were not. Postoperative intraocular pressure and number of glaucoma medications in paired eyes of the same patients were compared. Surgical success was defined as postoperative IOP of <20 mmHg without medication. Bleb morphology and the number of glaucoma medications were also compared in both eyes. Results: There was a positive correlation between the two eyes of a patient in the IOP values at each postoperative time point in both groups (with and without antimeta­bolites) (P > 0.05). At the last follow‐up visit after trabeculectomy, the number of glaucoma medications used in paired eyes were not significantly different (P > 0.83). Surgical failure occurred more often in paired eyes than in single eyes. Bilateral failure occurred in 60% (3/5) of the failed trabeculectomies with antimetabolites and in 100% (3/3) of the failed trabeculectomies without antimetabolites. Conclusion: Trabeculectomy outcome in paired eyes of patients was similar in both antimetabolites treated and untreated eyes. Thus, trabeculectomy outcome in the first operated eye can predict the surgical result in the second eye of the same patient.
Late reactivation of thyroid orbitopathy
Authors: Selva Dinesh , Chen Celia , King Georgina 
Published: February 2004

Abstract Background: Thyroid orbitopathy is characterized by spontaneous remissions and exacerbations. Although data on the natural history are scarce, the active phase is usually self‐limited, encompassing an average period of 18−36 months. Late reactivation, defined as active orbitopathy occurring after more than 5 years of quiescent disease, appears to be an uncommon and poorly documented event. The aim of the present study was to assess the incidence and characteristics of late reactivation of thyroid orbitopathy within a tertiary referral orbital clinic. Methods: A retrospective case review was conducted of patients with thyroid orbitopathy seen at the Royal Adelaide Hospital Orbital Clinic between 1996 and 2001. Results: From 193 cases of thyroid orbitopathy, eight cases (5%) of late reactivation were identified. The mean age of patients was 51 years (range 32−76 years) with a female to male ratio of 3:1. All cases presented with proptosis and seven demonstrated increased diplopia and gaze restriction. Signs of soft tissue inflammation were seen in three cases. All were euthyroid at presentation with a past history of thyroid orbitopathy and hyperthyroidism. One patient had an association of smoking with reactivation but the remainder had no discernible precipitants. The average interval between the initial orbitopathy and reactivation was 12 years (range 6−30 years). Computed tomography revealed enlarged extraocular muscles in seven cases and two showed partial response to treatment with low dose radiotherapy and steroids. The average length of disease activity was 14 months (range 9−18 months). Conclusion: Late reactivation of thyroid orbitopathy appears to be an uncommon phenomenon. It may occur under euthyroid conditions with no obvious precipitants and often presents as a reactivation of myopathy.
Arthur Thomas Paterson: the life and times of a New Zealand ophthalmologist
Authors: Hart Richard H , McGhee Charles NJ 
Published: February 2004

AbstractArthur Thomas Paterson was a pre‐eminent New Zealand ophthalmologist who settled in the United Kingdom after the First World War and became a leading figure in the development of ophthalmic services in the north‐east of England. This vignette explores his contributions to clinical education and the establishment of comprehensive ophthalmic services in Newcastle upon Tyne. It also highlights the Arthur Thomas Paterson scholarship bequest to enable New Zealand ophthal­mologists to acquire additional specialist training in inter­national centres of excellence.