bluuebunny/crossref_metadata_2025 huggingface dataset:
Tissue microarray (TMA) applications: implications for molecular medicine
Authors: Simon Ronald , Sauter Guido
Published: October 2003

Modern expression-screening platforms such as complementary DNA (cDNA) arrays allow for high-throughput lead discovery in cancer and other diseases. For evaluation of promising candidate genes, however, in situ analysis of high numbers of clinical tissues samples – for example, by immunohistochemistry or fluorescence in situ hybridisation – is mandatory. Tissue microarray (TMA) technology greatly facilitates such analysis. Minute tissue cores (diameter 0.6 mm) are removed from up to a thousand different conventional paraffin blocks and re-assembled in a single empty paraffin block at predefined positions. Sections of the resulting TMA can be utilised for the range of research applicable to conventional tissue sections. Important advantages of the TMA technology are speed (parallel analysis of up to a thousand tissues), cost efficiency (the same amount of reagents required for a single large-section analysis is sufficient for a thousand samples), and standardisation (the same experimental conditions are applied to all samples). Because of the high numbers of samples usually included in TMAs, they are optimally suited to detect genotype–phenotype associations with high statistical power. Thus, TMA technology will markedly accelerate the transition from basic research to clinical applications.
Genetic studies of osteoporosis
Authors: Brown Matthew A. , Duncan Emma L.
Published: October 2003

Osteoporosis is a common condition of men and women, which is characterised by an increase in bone fragility due to a reduction in the amount of bone tissue. Predisposition to osteoporosis is largely genetically determined, and it is likely that several genes, each having a small effect, are involved. Bone density is determined by the peak bone mass achieved, and the rate and timing of subsequent bone loss. Twin and family studies suggest that the genetic determinants of bone density in later life influence predominantly, but not exclusively, peak bone mass. Although many genes influence bone density in both males and females, at different skeletal sites and in different age groups, it is likely that the magnitude of individual genetic effects differs in different population subsets and in different environmental settings. Thus, weak to moderate genetic effects might be identified only in specific subsets of the population. Rapid advances in the field of human genetics during the past decade have greatly improved our chances of successfully identifying genes that are involved in complex genetic conditions such as osteoporosis, and ultimately might lead to the development of new diagnostic and predictive tests as well as novel treatments for this condition. In this review, we have outlined the methods that are currently being employed to identify osteoporosis genes and also the progress that has been made to date in this field.
Clinical
relevance of the molecular mechanisms of resistance to anti-cancer drugs
Authors: Brown Robert , Links Matthew
Published: October 2003

Resistance to anti-cancer drugs (drug resistance) can be defined in the laboratory
by the amount of anti-cancer drug that is required to produce a given level
of cell death (drug response). Clinical drug resistance can be defined either
as a lack of reduction of the size of a tumour following chemotherapy or as
the occurrence of clinical relapse after an initial ‘positive’ response
to anti-tumour treatment. Many studies of tumour samples do not directly measure
drug resistance in the laboratory (because it is difficult to perform functional
assays on tumour tissue); instead, key proteins or genes that are involved in
particular mechanisms of drug resistance have been proposed as ‘markers’
of drug resistance. In this review, we have focused on the problems that can
arise when attempts are made to relate the relevance of laboratory-identified
molecular mechanisms of drug resistance to anti-cancer drug resistance that
occurs in patients.
Permanent survival of organ transplants without immunosuppression: Experimental approaches and possibilities for tolerance induction in clinical transplantation
Authors: Bushell Andrew , Wood Kathryn J.
Published: October 2003

During the past 30 years, organ transplantation has developed from a highly experimental procedure into an important part of routine clinical practice. This is reflected by the fact that graft survival times, which were once considered in terms of days or weeks, are now measured in terms of years or decades, with enormous corresponding benefits for the patient. Much of this improvement is due to the development of sophisticated immunosuppressive drugs that inhibit the rejection response mediated by the immune system of the recipient. However, almost without exception, all of the grafts that are transplanted from one genetically disparate individual to another are eventually rejected. The Holy Grail in transplantation is the development of protocols that lead to transplantation tolerance and provide stable graft function without long-term drug therapy. In this article, we have discussed the need for alternatives to current immunosuppression and reviewed the results of animal models, which suggest that long-term stable tolerance is an achievable goal.
Carbon budget in the eastern and central Arabian Sea: An Indian JGOFS synthesis
Authors: Sarma V. V. S. S. , Swathi P. S. , Kumar M. Dileep , Prasannakumar S. , Bhattathiri P. M. A. , Madhupratap M. , Ramaswamy V. , Sarin M. M. , Gauns M. , Ramaiah N. , Sardessai S. , de Sousa S. N.
Published: October 2003

The carbon budget for the eastern and central Arabian Sea was constructed using results from the Modular Ocean Model and biogeochemical data collected largely under the Indian Joint Global Ocean Flux Study programme. The study region (east of 64°E and between 11° and 21°N) was divided into two vertical boxes; a surface box of the top 100 m that largely undergoes exchanges with atmosphere and exhibits relatively strong seasonal variability and a subsurface box between 100 and 1000 m. Water transport rates in surface layers were maximal (up to 83 × 1012 m3) in the southwest monsoon season. Sinking from surface driven by convection (25 × 1012 m3) largely supports lateral outflows of water in subsurface layers in the northeast monsoon. Surface waters are renewed 10 times faster (τ = 0.8 years) than intermediate waters (τ = 8 year). A net supply of 25 Tg C yr−1 is estimated to the upper 1000‐m water column of the study area by the physical pump. Photosynthetic activity (234 Tg C yr−1) does not seem to support total carbon demands (1203 Tg C yr−1) by bacteria and microzooplankton and mesozooplankton in the surface layers. Carbon demand rate requires organic carbon nearly double that of the total living biomass production rate (644 Tg yr−1) suggesting that most of the demand might be met from internal cycling involving zooplankton grazing/excretion activities. Sinking flux (69 Tg C yr−1) from surface accounts for about 30% of the total photosynthetic production rate indicating intense remineralization of organic matter in the surface layers of the Arabian Sea. Grazing and excretion of carbon by the microzooplankton and mesozooplankton appear to easily sustain perennial supersaturation of carbon dioxide in surface waters of the Arabian Sea and emission of 32 Tg C yr−1 to the atmosphere.
The dynamics of melting beneath Theistareykir, northern Iceland
Authors: Stracke Andreas , Zindler Alan , Salters Vincent J. M. , McKenzie Dan , Grönvold Karl
Published: October 2003

U‐Th disequilibrium data on a suite of postglacial basalts (<12,000 years old) from Theistareykir, northern Iceland, show a relatively high degree of U series disequilibrium. For 21 out of 27 samples from Theistareykir, 230Th excesses are within 25 ± 5%. Four samples have 230Th excesses >30%. The two geochemically and isotopically most depleted samples (picrites) have excess 230Th of about 15%, similar to enriched basalts from locations adjacent to Theistareykir (Draugarhraun and Asbyrgi). The large range in chemical and isotopic variations of the Theistareykir samples provides an excellent opportunity to investigate the influence of source heterogeneity on the degree of U series disequilibrium. The lack of correlation between U‐Th data and radiogenic isotope or chemical parameters indicates that source heterogeneity does not play an important role in creating the excess 230Th. Therefore the Theistareykir basalts provide evidence that the Th systematics result from variations in the timing of the melting and melt extraction process only. The relatively large and constant 230Th excesses for the bulk of the Theistareykir samples (20–30%) suggest that melting and melt extraction must be relatively reproducible, with the melting starting well within the garnet‐stability field. Near fractional melting models suggest residual porosity ≤0.1%, upwelling rates ≤1cm/yr (corresponding to melting rates ≤1*10−4 kg/m3yr), and melt ascent velocities ≥3–4m/yr. The lower 230Th excesses of about 15% in both the most depleted lavas from Theistareykir and enriched lavas from locations adjacent to Theistareykir (Draugarhraun and Asbyrgi) indicate some variation in the melting and melt extraction process. The low 230Th excesses of the most depleted melts (picrites) could either be an effect of slow melt migration or be caused by incomplete melt aggregation, with melts created at the very bottom of the melting regime being underrepresented. The low 230Th excesses of the most enriched lavas are most likely due to slow melt migration for melts created at some distance from the center of the melting regime.
A comprehensive survey of auroral latitude Pc5 pulsation characteristics
Authors: Baker Gregory J. , Donovan Eric F. , Jackel Brian J.
Published: October 2003

We surveyed 10 years of CANOPUS Churchill line magnetometer data for Pc5 pulsations and catalogued over 4500 hours of pulsation activity (3334 Pc5 pulsation intervals). Many previously observed Pc5 pulsation characteristics are evident in our data including the dawn/dusk occurrence asymmetry, antisunward propagation patterns, strong correlations between Pc5 band power spectral density (PSD) and solar wind flow speed, increased Pc5 pulsation occurrence during times of high solar wind speeds, and statistical evidence for Pc5 pulsation polarization sense reversals in latitude and local time (across local noon). Our investigation also revealed some as of yet unreported results such as a good correlation between solar wind speed/Pc5 band PSD in all MLT sectors, increased Pc5 pulsation occurrence with IMF Bz northward conditions (for all MLTs), and the prevalence of Pc5 pulsations under all Pc5 band relative power values. We used a subset of 800 data intervals which contained Pc5 pulsations in at least three Churchill line stations to search for pulsations that exhibit classic FLR characteristics. Four hundred and fifty of these pulsations matched the FLR criteria and we discovered that the FLR MLT occurrence distribution is asymmetric about local noon with more pulsations occurring in the morning sector (0600–1200 MLT) than the afternoon sector (1200–1800 MLT), and an absence of FLRs at local noon. We also found that the MLT occurrence distribution for the remaining 350 “non‐FLR” pulsations is symmetric about local noon and has a (nonzero) local minimum at noon. In contradiction with the results of some previous studies, we find no evidence of stable, recurring, discrete Pc5 pulsation frequencies in our data set. Instead, our statistics show a continuous distribution of central frequencies and a general lack of frequency stability throughout the course of individual Pc5 pulsation events.
Basin‐centered asperities in great subduction zone earthquakes: A link between slip, subsidence, and subduction erosion?
Authors: Wells Ray E. , Blakely Richard J. , Sugiyama Yuichi , Scholl David W. , Dinterman Philip A.
Published: October 2003

Published areas of high coseismic slip, or asperities, for 29 of the largest Circum‐Pacific megathrust earthquakes are compared to forearc structure revealed by satellite free‐air gravity, bathymetry, and seismic profiling. On average, 71% of an earthquake's seismic moment and 79% of its asperity area occur beneath the prominent gravity low outlining the deep‐sea terrace; 57% of an earthquake's asperity area, on average, occurs beneath the forearc basins that lie within the deep‐sea terrace. In SW Japan, slip in the 1923, 1944, 1946, and 1968 earthquakes was largely centered beneath five forearc basins whose landward edge overlies the 350°C isotherm on the plate boundary, the inferred downdip limit of the locked zone. Basin‐centered coseismic slip also occurred along the Aleutian, Mexico, Peru, and Chile subduction zones but was ambiguous for the great 1964 Alaska earthquake. Beneath intrabasin structural highs, seismic slip tends to be lower, possibly due to higher temperatures and fluid pressures. Kilometers of late Cenozoic subsidence and crustal thinning above some of the source zones are indicated by seismic profiling and drilling and are thought to be caused by basal subduction erosion. The deep‐sea terraces and basins may evolve not just by growth of the outer arc high but also by interseismic subsidence not recovered during earthquakes. Basin‐centered asperities could indicate a link between subsidence, subduction erosion, and seismogenesis. Whatever the cause, forearc basins may be useful indicators of long‐term seismic moment release. The source zone for Cascadia's 1700 A.D. earthquake contains five large, basin‐centered gravity lows that may indicate potential asperities at depth. The gravity gradient marking the inferred downdip limit to large coseismic slip lies offshore, except in northwestern Washington, where the low extends landward beneath the coast. Transverse gravity highs between the basins suggest that the margin is seismically segmented and could produce a variety of large earthquakes.
Mantle layering across central South America
Authors: Liu Kelly H. , Gao Stephen S. , Silver Paul G. , Zhang Yongkai
Published: November 2003

Imaging of seismic velocity discontinuities along a 3000 km profile across central South America at 20°S suggests that the depth variations of the 410‐km (d410) and 660‐km (d660) discontinuities are closely associated with the high‐velocity Nazca slab and juxtaposed low‐velocity oceanic mantle beneath the slab. The mantle transition zone thickness ranges from 220 km in the oceanic mantle to 270 km in a 600‐km‐wide area occupied by the deflected Nazca slab. The slab deflection has also been suggested by previous studies of seismic tomography and seismicity. This 50 km difference in the thickness corresponds to a lateral temperature variation of about 370°C between the two areas. The depth of d410 shows a gradual eastward decrease of about 10 km along the profile, corresponding to a temperature that is about 75°C cooler to the east. This variation is probably related to changes in the upper mantle geotherms associated with the transition from tectonically active to stable upper mantle. A low‐velocity anomaly in the upper mantle and mantle transition zone beneath eastern Brazil, previously detected by seismic tomography and interpreted as a fossil plume, produced no detectable perturbation in transition zone thickness. It is thus unlikely to extend to the transition zone or alternatively is not thermal in origin. Finally, we have observed several possible second‐order discontinuities at the depths of 230, 500, 600, 840, and 915 km beneath the western part of the study area.
Architecture and signal processing of sky wave over‐the‐horizon radar
Authors: Guo Xin , Ni Jin‐Lin , Liu Guo‐Sui
Published: October 2003

The sky wave over‐the‐horizon radar (OTHR) is unique in the radar family that employs the ionosphere to reflect the radar high frequency signal to illuminate the target from the top down, thus significantly extending the detection range and permitting wide‐area surveillance. Besides, the OTHR also shows its special advantages on low‐flying target detection, stealth target detection, and sea‐state remote sensing. This paper presents an overall review on the development and architecture of the sky wave OTHR as well as the signal processing schemes. In particular, the techniques on interference suppression, correction of ionospheric contamination, and target detection are analyzed in detail.
Transport and cycling of iron and hydrogen peroxide in a freshwater stream: Influence of organic acids
Authors: Scott Durelle T. , Runkel Robert L. , McKnight Diane M. , Voelker Bettina M. , Kimball Briant A. , Carraway Elizabeth R.
Published: November 2003

An in‐stream injection of two dissolved organic acids (phthalic and aspartic acids) was performed in an acidic mountain stream to assess the effects of organic acids on Fe photoreduction and H2O2 cycling. Results indicate that the fate of Fe is dependent on a net balance of oxidative and reductive processes, which can vary over a distance of several meters due to changes in incident light and other factors. Solution phase photoreduction rates were high in sunlit reaches and were enhanced by the organic acid addition but were also limited by the amount of ferric iron present in the water column. Fe oxide photoreduction from the streambed and colloids within the water column resulted in an increase in the diurnal load of total filterable Fe within the experimental reach, which also responded to increases in light and organic acids. Our results also suggest that Fe(II) oxidation increased in response to the organic acids, with the result of offsetting the increase in Fe(II) from photoreductive processes. Fe(II) was rapidly oxidized to Fe(III) after sunset and during the day within a well‐shaded reach, presumably through microbial oxidation. H2O2, a product of dissolved organic matter photolysis, increased downstream to maximum concentrations of 0.25 μM midday. Kinetic calculations show that the buildup of H2O2 is controlled by reaction with Fe(II), but this has only a small effect on Fe(II) because of the small formation rates of H2O2 compared to those of Fe(II). The results demonstrate the importance of incorporating the effects of light and dissolved organic carbon into Fe reactive transport models to further our understanding of the fate of Fe in streams and lakes.
Dependence of the decay phase of solar energetic electron events on the large‐scale IMF structure: ACE observations
Authors: Sarris Emmanuel T. , Malandraki Olga E.
Published: November 2003

Using recent measurements of energetic electrons (≥38 keV) by the ACE/EPAM experiment, we examine the dependence of the characteristic decay time of two impulsive solar electron events on the large‐scale structure of the Interplanetary Magnetic Field (IMF) within which the electrons are emitted. The technique of mapping the solar wind and extrapolating the frozen‐in magnetic field is used to obtain the large‐scale IMF structure within and beyond the location of the ACE spacecraft. We find that the electron event that occurred within a converging IMF structure exhibits a remarkably longer decay phase compared to the electron event observed inside a diverging IMF configuration. The observations provide strong evidence for the location of magnetic “barriers” in space beyond 1 AU and their role in determining the decay phase of solar energetic electron events and the establishment and maintenance of particle reservoirs in the heliosphere.
Greening of arctic Alaska, 1981–2001
Authors: Jia Gensuo J. , Epstein Howard E. , Walker Donald A.
Published: October 2003

Here we analyzed a time series of 21‐yr satellite data for three bioclimate subzones in northern Alaska and confirmed a long‐term trend of increase in vegetation greenness for the Alaskan tundra that has been detected globally for the northern latitudes. There was a 16.9% (±5.6%) increase in peak vegetation greenness across the region that corresponded to simultaneous increases in temperatures. We also examined the changes for four specific vegetation types using an 11‐yr finer resolution (1‐km) satellite data and found that the temporal changes in peak and time‐integrated greenness were greatest in areas of moist nonacidic tundra. These changes in greenness between 1981 and 2001 correspond approximately to a 171 g/m2 (±81 g/m2) increases in aboveground plant biomass for Alaskan tundra. This remotely sensed interpretation is conducted in the absence of long‐term biomass records in the region.
A consolidated technique for enhancing desert dust storms with MODIS
Authors: Miller S. D.
Published: October 2003

A new satellite‐based multispectral passive radiometer technique for daytime enhancement of airborne dust over water and land has been developed. The algorithm, which combines color information from multiple visible channels with near and far infrared measurements, provides an improved ability to distinguish areas of dust from water/ice clouds and bright desert backgrounds in enhanced false‐color imagery. While generally applicable to any sensor possessing the requisite spectral information, the method is demonstrated here using high spatial and spectral resolution digital data from the Moderate Imaging Spectroradiometer (MODIS) instruments carried aboard Earth Observing System (EOS) Terra and Aqua polar orbiter platforms.
Search for the heliosheath with Voyager 1 magnetic field measurements
Authors: Burlaga L. F. , Ness N. F. , Stone E. C. , McDonald F. B. , Acuña M. H. , Lepping R. P. , Connerney J. E. P.
Published: October 2003

The magnetic field measured by Voyager 1 (V1) near 85 AU from 2002.0 to 2003.17 has the expected properties for the heliospheric magnetic field at that distance and epoch of the solar cycle. These V1 magnetic field observations do not provide evidence for exit from the solar wind, entry into a subsonic region such as the heliosheath, or transit of the termination shock near 85 AU.
Objective identification of cloud regimes in the Tropical Western Pacific
Authors: Jakob Christian , Tselioudis George
Published: November 2003

Identifying cloud regimes and their role in the climate system can serve a multitude of purposes, ranging from a better understanding of clouds to guiding field experiments to improving the representation of clouds in models. This study describes early results in identifying cloud regimes from ISCCP data using cluster analysis. A simple algorithm for cloud regime identification is introduced and applied to data in the Tropical Western Pacific region. Four major cloud regimes, namely a shallow cumulus regime, a transparent isolated cirrus regime, thick cirrus with convection and a deep and probably organized convective regime are identified and their frequency of occurrence is quantified. The use of the regime information for various applications is discussed and the use of regime classifications for representativeness studies is presented using the ARM TWP sites as an example.
Lags, hysteresis, and double peaks between cosmic rays and solar activity
Authors: Kane R. P.
Published: October 2003

The 12‐month moving averages of solar indices and CR (cosmic ray intensity) were compared. The long‐term variation had a negative correlation (already known). From the hysteresis plots for five cycles (odd cycles 19, 21, 23; even cycles 20, 22), it was seen that whereas odd and even cycles showed different patterns, the detailed evolution in similar cycles (even or odd) was not alike. The reason for complication is as follows. On medium‐term time scales, in some sunspot cycle maxima (notably cycles 22 and 23), there were two peaks in solar indices separated by about 2 years. These were reflected in CR as two distinct minima, some with a lag of a few months but others almost coincident with maxima of solar indices. The implication would be that CR modulation as observed on Earth contains two parts: (1) long‐term variation due to magnetic field structure in total heliosphere, determined by convection‐diffusion and drift mechanisms (this part has time lags of several months and is characterized by hysteresis phenomenon) and (2) short‐term and medium‐term variations caused mainly by accumulated shock waves (Forbush effects and assotiated phenomena) with time lags of a few days, which in the scale of months or a year or two, would show a time lag zero). The second component would be especially important in maximum of solar activity.
Comparison of precipitable water vapor derived from radiosonde, GPS, and Moderate‐Resolution Imaging Spectroradiometer measurements
Authors: Li Zhenhong , Muller Jan‐Peter , Cross Paul
Published: October 2003

Atmospheric water vapor is highly variable in both space and time across the Earth, and knowledge of the distribution of water vapor is essential in understanding weather and global climate. In addition, knowledge of the amount of atmospheric water vapor is required for high‐precision interferometric synthetic aperture radar (InSAR) applications due to its significant impact on microwave signals, which is the principal motivation for this study. In order to assess the performance of different instruments, i.e., radiosondes (RS), Global Positioning System (GPS), and the Moderate‐Resolution Imaging Spectroradiometer (MODIS) and for measuring precipitable water vapor (PWV), coincident observations collected at the Atmospheric Radiation Measurement Southern Great Plains site and at the Herstmonceux site over a 8–11 month period are used for time series intercomparisons. In this study, the Terra MODIS near‐infrared water vapor products (Collection 3) were examined. In addition, a first spatial comparison of MODIS PWV and GPS PWV was performed using data covering all of Germany and kindly supplied by the GeoForschungsZentrum Potsdam. Time series comparisons of PWV between radiosondes and GPS show that the scale factors of PWV from radiosondes and GPS agreed to 4% with correlation coefficients higher than 0.98 and standard deviations about 1 mm. A significant day‐night difference was found for Vaisala RS90 radiosondes in comparison with GPS PWV, with nighttime launches having a scale factor 4% larger, but agreeing overall better. It is also shown that GPS PWV and RS PWV agreed better with each other than with MODIS PWV, and the differences of MODIS PWV relative to GPS or RS were larger than those between GPS PWV and RS PWV. MODIS PWV appeared to overestimate PWV against RS, with scale factors from 1.14 to 1.20 and standard deviations from 1.6 to 2.2 mm. MODIS PWV appeared to overestimate PWV against GPS, with scale factors from 1.07 to 1.14 and standard deviations varying from 0.8 to 1.4 mm in time series. The larger differences relative to MODIS PWV are likely to be caused by uncertainties in the spectroscopic database for the MODIS retrievals, calibration uncertainties in the radiances measured by MODIS, operational differences of the three systems, and different mapping functions adopted in GPS and MODIS PWV retrievals. We derived a linear fit model to calibrate MODIS PWV, and better agreements between calibrated MODIS PWV and GPS PWV in space have been achieved. This indicates that MODIS PWV products should be updated or calibrated using a linear fit model before being applied to correct InSAR measurements. Also, the potential accuracy of standard resolution (resampled) radiosonde data from the UK Met Office and the University of Wyoming has been assessed. It is demonstrated that some caution needs to be exercised when using standard resolution data.
Highlights of OH, H2SO4, and methane sulfonic acid measurements made aboard the NASA P‐3B during Transport and Chemical Evolution over the Pacific
Authors: Mauldin R. L. , Cantrell C. A. , Zondlo M. , Kosciuch E. , Eisele F. L. , Chen G. , Davis D. , Weber R. , Crawford J. , Blake D. , Bandy A. , Thornton D.
Published: October 2003

Measurements of hydroxyl radical (OH), sulfuric acid (H2SO4), and methane sulfonic acid (MSA) were performed aboard the NASA P‐3B using the selected ion chemical ionization mass spectrometry technique during the Transport and Chemical Evolution over the Pacific (TRACE‐P) study. Photochemical box model calculations of OH concentrations yielded generally good agreement with an overall tendency to overestimate the measured OH by ∼20%. Further analysis reveals that this overestimation is present only at altitudes greater than ∼1.5 km, with the model underestimating OH measurements at lower altitudes. Boundary layer H2SO4 measurements, performed in a volcanic plume off the southern coast of Japan, revealed some of the largest marine boundary layer H2SO4 concentrations ever observed and were accompanied by new particle formation. Nighttime measurements of OH, H2SO4, and MSA in the remote pacific off Midway Island revealed significant boundary layer concentrations of H2SO4 and MSA, indicating evidence of nighttime boundary layer oxidation processes but in the absence of OH. A cursory exploration of the sources of production of the H2SO4 and MSA observed at night is presented.
A quantitative analysis of short‐term 18O variability with a Rayleigh‐type isotope circulation model
Authors: Yoshimura K. , Oki T. , Ohte N. , Kanae S.
Published: October 2003

Stable water isotopes (D and 18O) in precipitation have large spatial and temporal variability and are used widely to trace the global hydrologic cycle. The two models that have been used in the past to examine the variability of precipitation isotopes are Rayleigh‐type models and isotope‐atmospheric general circulation models. The causes of short‐term (1–10 day) variability in precipitation isotopes, however, remain unclear. This study seeks to explain isotope variability quantitatively at such scale. A new water isotope circulation model on a global scale that includes a Rayleigh equation and the use of external meteorological forcings is developed. Transport and mixing processes of water masses and isotopes that have been neglected in earlier Rayleigh models are included in the new model. A simulation of 18O for 1998 is forced with data from the Global Energy and Water Cycle Experiment (GEWEX) Asian Monsoon Experiments (GAME) reanalysis. The results are validated by Global Network of Isotopes in Precipitation (GNIP) monthly observations with correlation R = 0.76 and a significance level >99% and by daily observations at three sites in Thailand with similar correlation and significance. A quantitative analysis of the results shows that among three factors that cause isotopic variability, the contribution of moisture flux is the largest, accounting for 37% at Chiangmai, and 46% globally. This highlights the importance of transport and mixing of air masses with different isotopic concentrations. A sensitivity analysis of the temporal and spatial resolution required for each variable is also made, and the model is applied to two additional data sets. The more accurate Global Precipitation Climatology Project (GPCP) precipitation data set yields improved model results at all three observation sites in Thailand. The National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis allows the simulation to cover 2 years, reproducing reasonable interannual isotopic variability.
Cometary and Interstellar Dust Analyzer for comet Wild 2
Authors: Kissel J. , Glasmachers A. , Grün E. , Henkel H. , Höfner H. , Haerendel G. , von Hoerner H. , Hornung K. , Jessberger E. K. , Krueger F. R. , Möhlmann D. , Greenberg J. M. , Langevin Y. , Silén J. , Brownlee D. , Clark B. C. , Hanner M. S. , Hoerz F. , Sandford S. , Sekanina Z. , Tsou P. , Utterback N. G. , Zolensky M. E. , Heiss C.
Published: October 2003

The Cometary and Interstellar Dust Analyzer (CIDA) instrument analyzes the composition of individual grains in the cometary coma. As each particle impacts a silver plate, the high‐impact energy due to the relative velocity of the spacecraft as it flies through the coma causes the elements and molecular compounds in the particle to become ionized. Using a fast time‐of‐flight mass spectrometer, a complete set of ions are detected for each impact, from a mass range of 1 (atomic hydrogen) up to a few thousand atomic mass units, encompassing all elements in the periodic table and many molecules, such as organic compounds. This experimental technique has already been applied with excellent success at Halley's comet, and the CIDA derivative instrument is flying on the Stardust mission, which will encounter comet Wild 2 in January of 2004. The data returned will give clues to the elemental and chemical composition of the dust component of this comet.
A precise numerical scheme for contaminant transport in dual‐well flow
Authors: Constales D. , Kačur J. , Malengier B.
Published: October 2003

A precise numerical method is developed for the simulation of contaminant transport in dual‐well flow. Our main motivation is the determination of model parameters by means of dual‐well tests. The method presented here guarantees a very low level of numerical dispersion. We have applied a bipolar transformation to the transport equation so that the convective term is parallel to one of the axes. In the time stepping, we split the transport and diffusion parts: the transport part is semianalytically solved (thanks to the bipolar transformation) via a multiple Riemann problem, and the diffusion part is solved using a finite volume method. Examples are provided to show that the method is suitable for parameter identification.
Vulnerability to severe weather and regulation of body mass of Icelandic and British Redshank Tringa totanus
Authors: Mitchell P.I. , Scott I. , Evans P.R.
Published: November 2003

During severe weather, Redshanks suffer the heaviest mortality amongst all the shorebird species wintering around the North Sea coasts of the British Isles. An earlier study had suggested that this resulted from a failure to accumulate sufficient body fat reserves before mid‐winter. Detailed field studies in northeast England between 1993 and 1995 of seasonal changes in body mass, and in estimated lean and fat masses, of two races of Redshank, both of which winter in the same estuary, were accompanied by similar studies of small numbers held in captivity with unlimited food. After differences in body size were allowed for, there were no differences in body composition and its seasonal pattern of change in birds of the Icelandic and British races. Body mass changes in wild birds paralleled those in captives between November and March, and mid‐winter levels were not limited by food supply; indeed they were slightly higher in a winter with lower prey densities. It is concluded that Redshanks regulate body mass and, indirectly, fat reserves at levels set by a trade‐off between the risks of predation and starvation. Unlike most other shorebird species, they take very small prey in relation to their body size and hence must feed for long periods during each tidal cycle to achieve their daily energy intake needs. Thus they have little scope to extend their feeding time during severe weather, which also forces them to feed on ice‐free exposed coastal habitats where wind chill cannot be avoided. Both factors lead to more rapid depletion of fat reserves than in other species which have higher energy intake rates or lower total daily requirements.
Migration strategies of sylviid warblers: chance patterns or community dynamics?
Authors: Howlett Peter , Jüttner Ingrid , Ormerod Steve J.
Published: November 2003

The effects of community dynamics in birds on the optimisation of their migratory strategies is a neglected area. For three years, we captured migrating warblers on autumn passage at a coastal site in western Britain. We used canonical correspondence analysis (CCA) to assess spatio‐temporal patterns of occurrence, and principal components analysis (PCA) to assess morphological variation. We calculated Euclidean distance in ordination and morphological space to assess separation between species pairs, and used Monte‐Carlo simulations to assess the probability of pattern occurring by chance.  Ordination revealed five species‐groups separated by habitat type and time of passage. Reed Warbler Acrocephalus scirpaceus and Sedge
Warbler A. schoenobaenus (Group 1) occurred in wet habitats and
peaked simultaneously. In drier habitats with scrub, a first wave of
Blackcap Sylvia atricapilla (Group 2) significantly preceded
Grasshopper Warbler Locustella naevia, Willow Warbler
Phylloscopus trochilus, Whitethroat Sylvia communis and
Lesser Whitethroat Sylvia curruca (Group 3), which in all but one
case (Lesser Whitethroat) significantly preceded Garden Warbler Sylvia
borin (Group 4); peak numbers of Chiffchaffs Phylloscopus
collybita and a second wave of Blackcaps (Group 5) occurred later
still. Age effects were found only in Acrocephalus, with adults peaking before juveniles.  For seven out of eight pairings within genera, separation in time of passage increased significantly in species that were morphologically similar. The only exception was Blackcap and Lesser Whitethroat which differed substantially in both passage time and morphology. Monte‐Carlo simulations showed that chance was unlikely to be responsible for ordination patterns, nor for inter‐specific variation in passage time and its relationship with species morphology.  These data provide annually consistent evidence that migrating sylviid warblers are separated ecologically by habitat use, time of passage and morphology: we cannot refute the hypothesis that community dynamics have influenced niche use and autumn migratory strategy. We call for further tests of the ‘migrant interaction’ hypothesis in other geographical locations and taxa, particularly where migrants are allopatric and interact ecologically only on migration.
Patterns of variation in ornaments of Crested Auklets Aethia cristatella
Authors: Jones Ian L. , Hunter Fiona M. , Fraser Gail
Published: November 2003

We investigated patterns of variation of feather and bill ornaments of Crested Auklets Aethia cristatella, a monogamous seabird, based on
963 individuals measured in the years 1990 to 1998. Three prominent
ornaments were displayed: a forehead crest, composed of 11–31
curved feathers averaging about 40 mm in length, bilaterally symmetrical
white auricular plumes on the sides of the head behind the eyes,
averaging about 30 mm in length, and brightly coloured semi‐circular
rictal plates at the corners of the bill. As in other putative sexually
selected traits, auklet ornaments were more variable across individuals
than non‐ornamental traits. Crest length and auricular plume length were
positively correlated within individuals but not across years. Among the
traits measured there was evidence for slight sexual dimorphism for the
auricular plume and rictal plate ornaments and for culmen length and
tarsus (males were slightly larger than females) but not for the crest
ornament. Breeding adult females and males had greater crest and plume
ornament expression than non‐breeding adults. Paradoxically,
females’ crests and rictal plates were more variable than
males’ crests and rictal plates. Based on independent samples, the
expression of feather ornaments and rictal plate varied among years
between 1990 and 1998. Crested Auklet ornaments did not vary in concert
with the ornaments of Whiskered Aethia pygmaea and Least Auklets
Aethia pusilla during this period. Crested Auklet subadults had smaller ornaments than adults. Based on adults remeasured after an interval of one to seven years, the size of individuals’ feather ornaments increased with age. We found no relationship between auricular plume length and asymmetry. Male auricular plumes and female crests were weakly correlated with body condition.
Environmental‐ and parental condition‐related variation in sex ratio of kestrel broods
Authors: Korpimäki Erkki , May Celia A. , Parkin David T. , Wetton Jon H. , Wiehn Jürgen
Published: November 2003

Variation of brood sex ratio was studied in a Finnish population of Eurasian Kestrels Falco tinnunculus breeding in an unpredictably variable environment. From those young that survived until 2–4 weeks of age, blood was collected and their sex determined from polymorphic DNA profiles produced by hybridisation with a human minisatellite probe. The sex ratio was male‐biased during a year of food (vole) scarcity. Furthermore, in broods without mortality, contrasting seasonal trends in sex ratios emerged. In this subsample, the proportion of males increased with later laying date during years of low and moderate food supply, whereas the opposite was true in a year of relatively high food supply. These trends may indicate circumstances that favour the raising of different sex. The proportion of males in the brood was negatively correlated with body condition of both male and female parents, also reflecting an adaptive condition‐dependent sex‐ratio adjustment, or alternatively the inability of the parents to meet the requirements of the more energetically expensive female offspring. We discuss the limitations that unpredictable conditions during brood raising can impose on adaptive sex‐ratio manipulation, particularly in species with sexual size dimorphism and consequent differences in the cost of raising the two sexes.
Associations between wintering avian predators and schooling fish in the Skagerrak‐Kattegat suggest reliance on predictable aggregations of herring Clupeaharengus
Authors: Skov Henrik , Durinck Jan , Andell Per
Published: November 2003

We investigated the distributional dynamics of piscivorous seabirds in relation to the distribution of young fish outside the breeding season in the Skagerrak and Kattegat, using synoptic bottom trawl and seabird surveys. Kittiwake Rissatridactyla, Common Guillemot
Uriaaalge and Razorbill Alcatorda were
significantly correlated with herring Clupeaharengus abundance at coarse spatial scales (>20 km). The association between the three seabird species and other abundant fish species like sprat
Sprattussprattus, whiting Merlangiusmerlangus and Norway pout Trisopterusesmarki was considerably weaker. In the Skagerrak and Kattegat, the location of aggregations of immature herring during winter is relatively stable and predictable. The correlation with herring and the lack of correlation with the abundant, but less stable occurrence of sprat of similar caloric value suggest that the tendency among piscivorous seabirds to depend on predictable concentrations of prey during the breeding season is a common feature during the non‐breeding season as well. The results are discussed in relation to ecological and winter habitat characteristics of wintering piscivorous seabirds in the eastern North Atlantic, and in relation to the management and conservation of nursering herring in the Skagerrak and Kattegat.
Strict monogamy in a semi‐colonial passerine: the Jackdaw Corvus monedula
Authors: Henderson I. G. , Hart P. J. B. , Burke T.
Published: November 2003

In this study we used DNA fingerprinting to provide an accurate measure of paternity in a nest‐box colony of Jackdaws. The species is a semi‐colonial, socially monogamous passerine which establishes long‐term pair bonds. Parents raise a single annual brood in which 50% brood reduction is commonplace. However, nest sites are a limited resource, non‐breeding adults are also common around colonies and males are frequently separated from their incubating females during the fertile egg‐laying period so that opportunities arise for extra‐pair copulation. The parentage analysis, however, revealed no cases of extra‐pair fertilisation (EPF) or intra‐specific brood parasitism. Therefore fledgling output or survival is likely to be a good measure of individual reproductive success in this species. The lack of EPFs is not explained by nesting synchrony and we discuss the relative costs and benefits to females of seeking EPFs; the likelihood that paternal care and a life‐history strategy similar to many long‐lived non‐passerines may also constrain the species to monogamy.
Prey selection and foraging performance of breeding Great Tits Parus major in relation to food availability
Authors: Naef‐Daenzer Luzia , Naef‐Daenzer Beat , Nager Ruedi G.
Published: November 2003

We studied the nestling diet and the foraging performance of Great Tits in relation to prey abundance in the field. Numerous experimental studies present data on foraging decisions in captive Great Tits. Little is, however, known about prey selection in the field in relation to the food available and the consequences this has for the food delivery rate to nestlings. Since the foraging performance of the parents is one of the main determinants of fledging weight and juvenile survival, foraging behaviour is an important part of Great Tit reproduction. During the early breeding season up to 75% of the prey biomass delivered to the nestlings were spiders, which is in contrast with other studies. Only when caterpillars reached a size of 10–12 mg (approximately the average size of the spiders caught at that time) did the Great Tits change their preferences and 80–90% of the delivered prey masses were caterpillars, as reported by other authors. This ‘switching’ between prey occurred within a few days. It was not related to the changes in abundance but to size of caterpillars. The rate at which caterpillars were delivered to the nestlings (in mg/nestling/h) was strongly correlated with the caterpillar biomass available (in mg/m of branches) and nestling growth rate was significantly influenced by the mass of available caterpillars. The results provide evidence why perfect timing of breeding is so important for the Great Tit, and contribute to the understanding of the causal link between food supply, growth and breeding success.
How costly is clutch formation in the Audouin's Gull Larus audouinii?
Authors: Ruiz Xavier , Jover Lluis , Pedrocchi Vittorio , Oro Daniel , González‐Solıs Jacob
Published: November 2003

During the Audouin's Gull's breeding season at the Ebro Delta in 1993, 24 fresh eggs from eight three‐egg clutches (modal clutch‐size) were collected at the peak of the laying period. Eggs were processed to obtain formalin‐fixed yolks, which were halved and stained using the potassium dichromate method. Digitized images of the yolks were examined to assess the daily rates of yolk deposition. We used these data in combination with egg compositional analysis to build a model of energy demands during the formation of an average clutch in Audouin's Gull. To show how the different parameters of clutch formation affect the daily energy investment peak, we performed a simulation analysis in which the rapid yolk development (RYD) period, the follicle triggering interval (FTI), the laying interval (LI) and the albumen synthesis period (ASP) were allowed to vary simultaneously. In our sample, the mean RYD period was seven days with a range from six to eight days. There were no significant differences in yolk volume among eggs in a clutch, but albumen volume was significantly smaller in third eggs. According to our model the albumen synthesis of the a‐egg coincides with the energy demand peak for clutch formation. This peak represents an increase by ca. 42% in female energy requirements. Values obtained from the simulation analysis showed that only the ASP of the a‐egg and the RYD durations of the second and third follicles produced noticeable reductions in peak energy investment. We predict that in gulls, whose laying intervals seem to be kept constant, significant increases of the durations of the RYD periods of second and third eggs, or even significant reductions of yolk size of these eggs, may operate simultaneously to match the energy demands during clutch formation to the prevailing food conditions.