bluuebunny/crossref_metadata_2025 huggingface dataset:
Our brains: transparency within bounds
Authors: WOLF GERALD
Published: March 2004

We already have considerable insight into the working of the brain, that part of our body which generates the mind, which makes us hope and wish and feel, and finally allows us to comprehend ourselves as ‘Self’. However, the big questions about what thinking, consciousness and emotions really consist of cannot be answered yet. Continued research on the brain persists, tackling one of the greatest challenges for the human mind, namely: to discover its own preconditions, to unravel its own prerequisites. May we hope (or fear) that, in the future, brain research we will be able to give the final answer to that everlasting question of philosophy ‘What makes us human?’ Or is there an epistemological barrier when we look at the human brain and the subjectivity generated by it? There are fundamental cognitive problems regarding the extreme complexity of the brain's system and the brain–mind question. On the other hand, the findings of brain research are already so compelling that their interpretations should be guidelines for the humanities and the social sciences.
Human nature without a soul?
Authors: JEEVES MALCOLM
Published: March 2004

Rapid developments in neuroscience over the past four decades continue to receive wide media attention. Each new reported advance points to ever tightening links between mind and brain. For many centuries, what is today called ‘mind-talk’ was familiar as ‘soul-talk’. Since, for some, the possession of a soul is what makes us human, the challenges of cognitive neuroscience directly address this. This paper affords the non-specialist a brief overview of some of the scientific evidence pointing to the ever tightening of the mind-brain links and explores its wider implications for our understanding of human nature. In particular it brings together the findings from so-called bottom-up research, in which we observe changes in behaviour and cognition resulting from experimental interventions in neural processes, with top-down research where we track changes in neural substrates accompanying habitual modes of cognition or behaviour. Further reflection alerts one to how the dualist views widely held by New Agers, some humanists and many religious people, contrast with the views of academic philosophers, theologians and biblical scholars, who agree in emphasizing the unity of the person.
Civil society from a historical perspective
Authors: KOCKA JU¨RGEN
Published: March 2004

In many languages, the concept of ‘Civil society’ has had an astonishing career over the last 10 to 15 years, in disciplines such as history and sociology as well as with the public at large. This article presents a short history of the concept, offers a definition and explores the reasons for its popularity by identifying its conceptual ‘opponents’, which have changed over time. It discusses the changing relations between civil society, the market economy, government and the private sphere. It deals with the affinity between civil society and the middle classes in some areas and periods. It finally explores the trends and limits of the emergence of a transnational civil society in Europe. It is an overview that deals with the present problems from a historical perspective.
Striking the balance: economics and the environment
Authors: SANDMO AGNAR
Published: March 2004

The environment has many of the properties that economists associate with the concept of a public good. It has long been realized that, if left to itself, the market economy is likely to lead to an undersupply of public goods and, in the environmental area, to an insufficient use of resources to preserve environmental quality. Economics research in this area has concentrated on three central issues. First, exactly why is it that a market economy fails to allocate resources efficiently in the presence of environmental public goods or externalities? Second, how can one assess the economic value of environmental goods? Third, what kinds of policy are best suited for the protection of the environment, e.g. should one rely on tax and price incentives or on quantitative regulations? This article discusses these questions and also describes the evolution of the economic perspective on the environment, from a concern with local problems to focus on international and global issues of environmental pollution.
The case of the stolen rooms
Authors: VAN DELFT DIRK
Published: March 2004

Heike Kamerlingh Onnes (1853–1926) was famous for the Cryogenic Laboratory he built up at Leiden University. Hendrik Antoon Lorentz (1853–1928), Professor of theoretical physics at the same university and Onnes' closest colleague, left Leiden in 1912. According to Lorentz's daughter, this move had been initiated by a ‘trick’ Onnes had played on her father a few years earlier. Lorentz had been given two small laboratories for his personal use, but within a short time, according to Lorentz' daughter, Onnes just pinched those rooms and added them to his big laboratory. How did Kamerlingh Onnes and Lorentz get along together, and what really happened in the ‘case of the stolen rooms’?
Nonlinear multivariate and time series analysis by neural network methods
Authors: Hsieh William W.
Published: March 2004

Methods in multivariate statistical analysis are essential for working with large amounts of geophysical data, data from observational arrays, from satellites, or from numerical model output. In classical multivariate statistical analysis, there is a hierarchy of methods, starting with linear regression at the base, followed by principal component analysis (PCA) and finally canonical correlation analysis (CCA). A multivariate time series method, the singular spectrum analysis (SSA), has been a fruitful extension of the PCA technique. The common drawback of these classical methods is that only linear structures can be correctly extracted from the data. Since the late 1980s, neural network methods have become popular for performing nonlinear regression and classification. More recently, neural network methods have been extended to perform nonlinear PCA (NLPCA), nonlinear CCA (NLCCA), and nonlinear SSA (NLSSA). This paper presents a unified view of the NLPCA, NLCCA, and NLSSA techniques and their applications to various data sets of the atmosphere and the ocean (especially for the El Niño‐Southern Oscillation and the stratospheric quasi‐biennial oscillation). These data sets reveal that the linear methods are often too simplistic to describe real‐world systems, with a tendency to scatter a single oscillatory phenomenon into numerous unphysical modes or higher harmonics, which can be largely alleviated in the new nonlinear paradigm.
Two examples of magnetic clouds with double rotations observed by the Ulysses spacecraft
Authors: Rees A. , Forsyth R. J.
Published: March 2004

A survey of Ulysses magnetometer data has been carried out between Oct 1990 (launch) and Apr 2003 (just after the second northern polar pass) cataloguing magnetic cloud (MC) signatures, i.e., a smooth magnetic field rotation and enhanced magnetic field magnitude. After confirming that each of these events was a true MC by checking for a low proton temperature signature, it was possible to fit a constant α, force‐free flux rope model to each event. This allows parameters describing the global magnetic field configuration of the event in the region of the intersection with the spacecraft's trajectory to be determined. The survey has shown that associated with many MC field rotations there is a second, less well‐defined, rotation. Usually this rotation is so poorly defined that it is impossible to fit the flux rope model to it. However, in two specific cases, presented here, it has been possible to produce good model fits to both rotations. This gives insights into the chirality and relative orientations of the two flux ropes, assuming that is what they are. The results suggest that the two rotations are part of the same, deformed, rope through which the spacecraft has passed at two different points.
Enhancement of primary productivity in the western North Pacific caused by the eruption of the Miyake‐jima Volcano
Authors: Uematsu Mitsuo , Toratani Mitsuhiro , Kajino Mizuo , Narita Yasushi , Senga Yasuhiro , Kimoto Takashi
Published: March 2004

The eruption of the Miyake‐jima Volcano (34.08°N, 139.53°E) in the Izu Islands, Japan, 180 km SSW of Tokyo, began on 8 July 2000. A substantial amount of NH3 gas was found to be emitted from the Miyake‐jima Volcano together with SO2 gas and that geochemically significant quantities of aerosol particles composed of ammonium sulfate form in the plume. Through the use of satellite images, the additional atmospheric deposition of ammonium sulfate caused an increase of phyto‐plankton in the nutrient‐deficient region south of the Kuroshio. The emission of volcanic gases from the Miyake‐jima has likely been modifying the marine air quality as well as the open ocean ecosystem over parts of the western North Pacific for the past several years.
Relationship of surface O3 to large‐scale circulation patterns during two recent winters
Authors: Mao Huiting , Talbot Robert
Published: March 2004

We demonstrate a direct connection between large‐scale circulation patterns and surface O3 using atmospheric observations obtained during winters 2002 and 2003. Measurements at two rural sites in the northeastern U.S. revealed that median mixing ratios of O3 in winter 2003 were increased by up to 80% compared to 2002, and greatly exceeded previous spring annual maximums. To explain this we propose that strong meridional flows in winter 2003 frequently transported O3‐rich mid‐tropospheric air masses from high latitudes to the northeastern U.S. while cooling regional climate 4.4°C below normal. Our measurements also show that an exceptionally elevated spring O3 maximum occurred in 2003. The impact from this winter enhancement on the levels of O3 and other species during the following months will be largely driven by actual climatic conditions.
Aerosol partitioning in natural mixed‐phase clouds
Authors: Henning S. , Bojinski S. , Diehl K. , Ghan S. , Nyeki S. , Weingartner E. , Wurzler S. , Baltensperger U.
Published: March 2004

In situ aerosol and cloud drop microphysical measurements at a high‐alpine site are used to investigate aerosol partitioning between cloud and interstitial phases in natural, mid‐latitude, mixed‐phase clouds. Measurements indicate a decrease in the activated aerosol fraction (FN) for particle diameters dP > 100 nm with cloud temperature from FN ∼ 0.54 in summer liquid‐phase clouds to FN ∼ 0.08 in winter mixed‐phase clouds. The latter may be attributed to the Bergeron‐Findeisen mechanism whereby ice crystals grow at the expense of liquid water drops, releasing formerly activated aerosols back into the interstitial phase. This provides a means to distinguish the indirect effects of aerosols on drops and ice crystals.
Remote sensing evidence for baroclinic tide origin of internal solitary waves in the northeastern South China Sea
Authors: Zhao Zhongxiang , Klemas Victor , Zheng Quanan , Yan Xiao‐Hai
Published: March 2004

Evidence for baroclinic tide origin of internal solitary waves (ISWs) in the northeastern South China Sea is presented, based on 116 internal wave packets observed in satellite images from 1995 to 2001. These wave packets can be divided into two types, a single‐wave ISW packet containing only one ISW with/without an oscillating tail, and a multiple‐wave ISW packet composed of a group of rank‐ordered ISWs. All of the 22 single‐wave ISW packets occur in the deep water zone. It is suggested that the ISWs, instead of being generated by the lee‐wave mechanism, are developed by nonlinear steepening of the baroclinic tides, which are produced by the strong tidal currents flowing over a ridge in Luzon Strait. This suggestion is verified by an ERS‐2 SAR image, which records such an evolution process from a baroclinic tide to a single ISW in its spatial domain.
Large‐scale treeline changes recorded in Siberia
Authors: Esper Jan , Schweingruber Fritz H.
Published: March 2004

Analysis of a multi‐species network of western Siberian ecotone sites revealed pulses of tree invasion into genuine treeless tundra environments in the 1940s and 1950s and after the early 1970s. In addition, increases in radial stem growth synchronous to the late 20th century treeline change are observed. Both treeline changes and growth increases correspond with decadal‐scale periods of temperature that are warmer than in any other period since observations started, suggesting ‐ even if indirect ‐ the sensitivity of large‐scale treeline changes to this climatic forcing. The mid 20th century recruitment period reported here for the western Siberian network is compared with local findings from Europe and North America suggesting a circumpolar trend perhaps related to climate warming patterns. For western Siberia, the presence of relict stumps, nevertheless, indicates that this present colonization is reoccupying sites that had tree cover earlier in the last millennium.
Analysis of diurnal and seasonal cycles and trends in climatic records with arbitrary observation times
Authors: Vinnikov Konstantin Y. , Robock Alan , Grody Norman C. , Basist Alan
Published: March 2004

Many long‐term records of climate variables have missing data or have had changes in their times of observation. Here we present a technique to analyze such inhomogeneous records. We assume that the underlying climatic processes are nonstationary, where the observations contain a long‐term trend superimposed on periodic shorter time seasonal and diurnal cycles. The seasonal and diurnal variations are approximated using a limited number of Fourier harmonics, while the trend is represented by a monotonic function of time whose amplitude can also vary seasonally and diurnally. A least squares method is used to estimate the unknown Fourier coefficients. As an example of the technique, we present an analysis of multi‐decadal hourly observations of surface air temperature obtained from several meteorological stations within the United States.
Impact of aerosols and atmospheric thermodynamics on cloud properties within the climate system
Authors: Matsui Toshihisa , Masunaga Hirohiko , Pielke Roger A. , Tao Wei‐Kuo
Published: March 2004

A combination of cloud‐top and columnar droplet sizes derived from the multi Tropical Rainfall Measurement Mission (TRMM) sensors reveals the sensitivity of the aerosols effect on cloud‐precipitation processes due to environmental vertical thermodynamic structure. First, the magnitude of aerosol indirect effect could be larger with the analysis of columnar droplet sizes than that derived from the cloud‐top droplet sizes since column‐droplet size can account for the broader droplet spectra in the cloud layers. Second, a combination of cloud‐top and columnar droplet sizes reveals that the warm rain process is prevented regardless of the aerosols concentration under high static stability such as when a strong temperature inversion exists, while a high aerosol concentration suppresses the warm rain formulation under low static stability.
Thermospheric up‐welling in the cusp region: Evidence from CHAMP observations
Authors: Lühr H. , Rother M. , Köhler W. , Ritter P. , Grunwaldt L.
Published: March 2004

The satellite CHAMP with its sensitive accelerometer on board provides the opportunity to investigate the thermospheric dynamics in great detail. In this study we concentrate on density structures in the cusp. During 25 Sep. 2000, the day we take as an example, air density enhancements of almost a factor of two are observed whenever the satellite passes the cusp region. For the interpretation of these events we consider also the concurrent ionospheric Hall and field‐aligned currents (FACs). As expected, sizable currents are found in the regions of dense air. Small‐scale FAC filaments (1‐km size) seem to play an important role in the heating. Whenever these very intense FACs with amplitudes of several hundreds of μA/m2 show up, density enhancements occur.
Analysis of the diurnal and semiannual variations of Dst index at different activity levels
Authors: Chen Hong‐Fei
Published: March 2004

The diurnal and semiannual variations of the geomagnetic disturbances for different activity levels exhibit distinct characteristics. In this paper, the variations are analyzed for different activity levels on the basis of the Dst index. For the activity level Dst ≈ 0 nT, the disturbance variations may be the manifestation of the residual Sq‐field and the Chapman‐Ferraro current field. The disturbances on this level may be ascribed to the uneven distribution of the Dst stations. For the higher activity levels, the disturbances and their diurnal variations are mainly contributed by magnetic storms. The analysis shows that the diurnal variation of the disturbances for the level around −100 nT in J‐months (May to August) is in reversed phase in comparison with that in D‐months (January, February, November, and December). For high activity levels, the diurnal variations of disturbances may be associated with the tilt angle of the geomagnetic axis in the GSM coordinates. The effect of the disturbance fields of asymmetrical current systems may exist as a part in the diurnal variation of the Dst index. This effect is relating to the activity level concerned.
Parametric interaction of kinetic Alfvén waves with convective cells
Authors: Pokhotelov O. A. , Onishchenko O. G. , Sagdeev R. Z. , Balikhin M. A. , Stenflo L.
Published: March 2004

The theory of parametric interaction of kinetic Alfvén waves (KAWs) with convective cells in finite β plasmas is reconsidered. We use nonlinear equations that account for nonzero electron temperature effects. With the help of a standard multiscale expansion, we then derive a general equation for the electrostatic and magnetostatic convective cells. It is found that the electrostatic convective cells represent vortex plasma motions (VPM) with very large impedance ratio. They are associated with the large‐scale part of the dispersion relation. On the other hand, the short‐scale convective cells correspond to filamentary field‐aligned current (FAC) structures or magnetostatic modes. A close inspection of our new dispersion relation shows that the electrostatic convective cells as well as the magnetostatic modes do not grow when the Alfvén waves are in the kinetic regime, i.e., in finite β plasmas. The relevance of our theory to satellite observations is stressed.
Generation of convective cells by kinetic Alfvén waves in the upper ionosphere
Authors: Onishchenko O. G. , Pokhotelov O. A. , Sagdeev R. Z. , Stenflo L. , Treumann R. A. , Balikhin M. A.
Published: March 2004

We consider the nonlinear interaction of finite amplitude kinetic Alfvén waves (KAW) with parametrically excited convective motions in the Earth's upper ionosphere, accounting for nonzero ion‐Larmor radius effects. The generation of the convective cells is due to the Reynolds stresses of the Alfvén waves. These stresses are nonzero only when the perpendicular wavelengths of the kinetic Alfvén waves are of the order of the ion‐Larmor radius. It is found that the wave vector of the fastest growing convective mode is perpendicular to that of the pump KAW. The instability growth rate is compared with those of other channels for the parametric decay of KAWs. Applications to satellite observations of KAWs in the auroral ionosphere are proposed, suggesting that convective cells produced by the parametric instability of KAWs can contribute to the turbulence in the plasma of the upper ionosphere.
Timing of the Martian core dynamo
Authors: Arkani‐Hamed Jafar
Published: March 2004

Using the radial component magnetic data acquired by Mars Global Surveyor during its mapping phase, a reliable magnetic anomaly map of Mars is derived. Many weak but reliable magnetic anomalies are now detected in the northern lowlands. Their source bodies have likely been partially demagnetized by the lowlands formation processes, and there has been no core field in the later times to remagnetize the bodies. No consistent anomalies are observed in the Hellas basin, implying that the core dynamo has been inactive at least since the impact event. The topography, the positive Bouguer anomaly at the center, and the strong negative Bouguer anomalies over the outskirts of Thaumasia plateau suggest that the plateau was the site of a large impact basin prior to the formation of the plateau. The lack of magnetic anomalies in the central part and the strong magnetic anomalies over the outskirts of the plateau resemble the magnetic signature of Hellas basin, implying a preexisting giant impact basin beneath the plateau and the absence of the core field since the impact time. The lack of magnetic edge effects of Valles Marineris, the absence of thermal demagnetization of Tharsis plain by the shield volcanoes, and the substantial distance between the paleomagnetic poles and the present rotation axis imply that a major part of Tharsis bulge was formed in the absence of the core field.
Thermal infrared analysis of weathered granitic rock compositions in the Sacaton Mountains, Arizona: Implications for petrologic classifications from thermal infrared remote‐sensing data
Authors: Michalski Joseph R. , Reynolds Stephen J. , Sharp Thomas G. , Christensen Philip R.
Published: March 2004

Critical to spectral interpretations of geologic surfaces on the Earth and Mars is an understanding of the relationship between the composition of weathered rock surfaces and whole‐rock mineralogy. In this study, thermal infrared spectroscopic and remote‐sensing analyses were used to determine the composition of weathered granitoid rock surfaces in the Sacaton Mountains, Arizona. A linear spectral deconvolution approach was employed to determine the mineralogies of naturally exposed, weathered surfaces and artificially exposed, fresh rock surfaces. Deconvolution results from fresh rock surfaces yield similar bulk mineralogy to results from point counting of rock slabs and thin sections. Deconvolution of weathered rock spectra indicate that compared to fresh samples, weathered surfaces are deficient in plagioclase feldspar and are enriched in clay minerals. The differential weathering of feldspar minerals impacts the interpretation of whole‐rock mineralogy and the spectral classification of bedrock geology, which, for plutonic rocks, is dependent on the relative proportions of different feldspars. Deconvolutions of multispectral remote‐sensing or laboratory data show a deficiency of total feldspar in the weathered rock units but lack sufficient spectral resolution for the discrimination between different feldspars. These results demonstrate that the differential breakdown and removal of primary minerals in rock surfaces due to weathering can affect the interpreted rock petrology from remote‐sensing studies. The relationships observed in our granitic samples could be applied to any rock type and may be important to consider for remote sensing of Mars.
Water mass stability reconstructions from greenhouse (Eocene) to icehouse (Oligocene) for the northern Gulf Coast continental shelf (USA)
Authors: Kobashi Takuro , Grossman Ethan L. , Dockery David T. , Ivany Linda C.
Published: March 2004

Shallow water mass characteristics such as temperature and density profile play a critical role in the climate system. We have developed a new method by which to reconstruct the ancient shallow water mass stability on the continental shelf using oxygen isotope variation within mollusc shells and fish otoliths and applied the method to an important interval in Earth history, the most recent transition from Greenhouse (Eocene) to Icehouse (Oligocene) climate modes. We define the slope of summer temperature (density) versus the seasonal range in temperature (density) as an indicator of water mass stability. In addition, extrapolation of the regression to zero seasonality is a proxy for temperature at the bottom of the seasonal thermocline (TBST). During the greenhouse world (the early Eocene and middle Eocene) the water mass plot shows an unstable water mass, agreeing with previous planktonic foraminiferal studies showing that temperature gradients at this time were much smaller than at present. During the middle to late Eocene transition, a substantial increase in water mass stability occurred. Significant cooling (∼5°C) of the TBST at this transition indicates that the greater cooling of deeper water relative to surface water caused the increase in water mass stability. The changes in water column structure at this transition were the most likely cause of a major extinction of planktonic foraminifera from warm to cold water taxa. The late Eocene T‐ΔT profile is very similar to modern profiles, suggesting that shallow water mass structure became similar to that of the modern Gulf Coastal shelf by the late Eocene. At the Eocene/Oligocene (E/O) boundary, no major change in water mass structure is identified. This agrees with the observation that no major extinction of planktonic foraminifera is found at the E/O boundary.
Heinrich events: Massive late Pleistocene detritus layers of the North Atlantic and their global climate imprint
Authors: Hemming Sidney R.
Published: March 2004

Millennial climate oscillations of the glacial interval are interrupted by extreme events, the so‐called Heinrich events of the North Atlantic. Their near‐global footprint is a testament to coherent interactions among Earth's atmosphere, oceans, and cryosphere on millennial timescales. Heinrich detritus appears to have been derived from the region around Hudson Strait. It was deposited over approximately 500 ± 250 years. Several mechanisms have been proposed for the origin of the layers: binge‐purge cycle of the Laurentide ice sheet, jökulhlaup activity from a Hudson Bay lake, and an ice shelf buildup/collapse fed by Hudson Strait. To determine the origin of the Heinrich events, I recommend (1) further studies of the timing and duration of the events, (2) further sedimentology study near the Hudson Strait, and (3) greater spatial and temporal resolution studies of the layers as well as their precursory intervals. Studies of previous glacial intervals may also provide important constraints.
An assessment on the performance of a dual‐wavelength (13.6/35.0 GHz) radar to observe rain and snow from space
Authors: Adhikari Nanda Bikram , Nakamura Kenji
Published: March 2004

An assessment on the performance of a dual‐wavelength (13.6/35.0 GHz) precipitation radar to observe snow and rain from space is drawn based on a simplified model, so‐called noncoalescence and nonbreakup model, for falling hydrometeors. The simulation, first, generates vertical profiles of dual‐wavelength radar integral parameters using raindrop size distribution (DSD) data measured at ground. The simulation results are then compared with some typical observations. Despite many uncertainties and assumptions, the simulated reflectivity profiles have shown some degrees of consistency with observations. The results based on statistical analysis of the simulated effective reflectivity factors (Zes) at 13.6 (Ze14) and 35 (Ze35) GHz radar frequencies indicate that: (1) rain and dry snow signatures are separable, if Ze14 is above ∼10 dBZ, (2) separation of rain and wet snow signatures is feasible, only if Ze14 is between ∼25 and ∼45 dBZ, while above ∼45 dBZ (Ze14) rain and wet snow signatures are poorly separable, and (3) separation of Ze signatures for dry and wet snow is rarely feasible. Moreover, from the analysis of the maximum allowable fluctuation in the standard deviations in Zes for rain and snow (dry and wet), this study proposes “rain/snow discrimination thresholds”. The rain/snow separation aspect is also studied with different distributions of snow density. Also, this study proposes conventional type Ze14‐R relationships for snowfall rate retrieval for dry and wet snow regions.
Wavelet analysis of variability in annual Canadian streamflows
Authors: Coulibaly Paulin , Burn Donald H.
Published: March 2004

Wavelet analysis is used to identify and describe variability in annual Canadian streamflows and to gain insights into the dynamical link between the streamflows and the dominant modes of climate variability in the Northern Hemisphere. Results from applying continuous wavelet transform to mean annual streamflows from 79 rivers selected from the Canadian Reference Hydrometric Basin Network (RHBN) reveal striking climate‐related features before the 1950s and after the 1970s. The span of available observations, 1911–1999, allows for depicting variance for periods up to 12 years. Scale‐averaged wavelet power spectra are used to simultaneously assess the interannual and spatial variability in 79 annual streamflow time series. The most striking feature, in the 2–3 year band and in the 3–6 year band (the 6–12 year band is dominated by white noise (since 1950) and is not considered further) is a net distinction between the timing and intensity of the interannual variability in western, central, and eastern streamflows, which is shown to be linked to the regional climatology. It is found that for the 2–3 year band, the Canadian streamflows are depicted mainly by the Pacific North America (PNA) during 1950–1999, and the Northern Hemisphere Annular Mode (NAM) only prior to 1950, and the North Atlantic Oscillation (NAO) after 1970. Similarly, in the 3–6 year band, the streamflows are depicted mostly by the NAO, the sea surface temperature anomalies over the Niño‐3 region (ENSO3) and the PNA during the period 1950–1999, and the NAM prior to 1950. Furthermore, strong local correlations between teleconnection patterns and western, central, and eastern streamflows are also revealed in both the 2–3 and 3–6 year bands with striking changes around 1950 and 1970. The correlation analysis in the 2–3 year and 3–6 year bands revealed the presence of two change points in the west and east streamflows occurring around 1950 and 1970.
Modeling decadal bed material sediment flux based on stochastic hydrology
Authors: Singer Michael Bliss , Dunne Thomas
Published: March 2004

Estimates of decadal bed material sediment flux and net storage are derived by driving sediment transport calculations with a stochastic hydrology model. The resulting estimates represent the whole distribution of sediment flux based on natural variability in channel characteristics (gradient, width, and bed grain size) and the magnitude, duration, and interarrival time of flood events. A procedure for calibrating a fractional sediment transport equation of a commonly used form to bed material grain size distributions (BMGSDs) at cross sections is presented. The procedure was applied to the Sacramento River channel network to compute estimates of annual total and annual peak bed material discharges into and through the main stem over a 30‐year period. Main stem bed material budgets were evaluated to identify reaches in states of net accumulation or scour. Simulations highlight large imbalances in sand and gravel storage throughout the Sacramento River, which can be explained by a combination of local hydraulics and BMGSDs and for which there is at least some empirical support.
Solute transport through the integrated groundwater‐stream system of a catchment
Authors: Lindgren G. A. , Destouni G. , Miller A. V.
Published: March 2004

We present a coupled groundwater‐stream model of catchment‐scale solute transport, using a Lagrangian stochastic advective‐sorptive travel time approach. We consider distributed solute input over an entire catchment and investigate the resulting stream solute breakthrough, subject to the possible solute spreading mechanisms: (1) variable groundwater advection and solute mass transfer between mobile and immobile groundwater zones and (2) in‐stream advection, mixing, and solute mass transfer between stream water and hyporheic zone. Among these mechanisms we show that fractal solute spreading over a wide timescale range is, for realistic parameter values, obtained in the stream only for the condition combination of both variable solute advection and solute mass transfer in the groundwater, with mean groundwater advection to mass transfer rate ratio that falls within a certain value range and with only a small fraction of solute input mass following fast overland and/or storm soil water flow to the stream.
Moving beyond the IGY: The Electronic Geophysical Year (eGY) concept
Authors: Baker D. N. , Barton C. , Rodger A. S. , Fraser B. , Thompson B. , Fapitashvili V.
Published: March 2004

The International Geophysical Year (1957–1958) was inspired by the realization that much better and more complete information was needed about the Earth and geospace to understand and manage the complete terrestrial environment on which we depend. So it was that the IGY member countries worked together to deploy a large number of geophysical observatories around the world. These nations were pursuing the major IGY objectives to collect geophysical data as widely as possible, and to provide free access to these data for all scientists around the globe. About 50 permanent stations were set up in the Arctic and Antarctic, and the World Data Center System was established to ensure that the data collected were properly archived and made available without restrictions for scientific research and practical applications.
NASA Rover finds evidence of a once wet and habitable Mars
Authors: Showstack Randy
Published: March 2004

NASA's Opportunity rover has found strong evidence that a rock outcrop in Mars' Meridiani Planum region once was a wet and habitable environment, rover science team members announced at a 2 March news briefing at NASA headquarters in Washington, D.C.

“We have concluded that the rocks here were once soaked in liquid water”said Steven Squyres, Mars Exploration Rover principal investigator and astronomy professor at Cornell University. He said it was not yet possible to indicate how long ago or for how long the rocks were wet.
University of Connecticut Geology Department faces dissolution
Authors: Showstack Randy
Published: March 2004

The University of Connecticut's board of trustees is expected to vote in favor of dissolving the school's department of geology and geophysics at its 23 March meeting.

The board has been prompted to act for several reasons, including a perceived lack of cohesion and direction within the department. An Internet petition drive to save the geology department had garnered nearly 3,800 signatures by 6 March. However, some individuals, including department chair Raymond Joesten, view dissolution as a potentially positive measure that would allow geology and geophysics studies in the university to move forward.
Back to the future
Authors: Witton Leah Christen
Published: March 2004

Past Global Changes (PAGES) is a worldwide program that seeks to facilitate international and interdisciplinary collaborations aimed at understanding the Earth's past environment to make sound predictions for the future. PAGES' scope of interest includes the physical climate system, biogeochemical cycles, ecosystem processes, biodiversity and human dimensions.

PAGES is a core project of the International Geosphere‐Biosphere Programme (IGBP) and is funded by the U.S. National Science Foundation, the National Oceanic and Atmospheric Administration, and the Swiss National Science Foundation; and is overseen by a Scientific Steering Committee comprised of members chosen to provide a range of scientific expertise and a balance of nationalities. It is run by a small International Project Office that serves as a critical interface between scientists and science initiatives. The Office manages projects; organizes and supports meetings and courses; aids in synthesizing research results in collaboration with scientists at large; publishes a free, international science newsletter; and provides and maintains a Web site that offers a variety of additional services. PAGES has over 3000 member scientists in more than 100 countries around the world. Membership is free and open to anyone. The PAGES Web site, www.pages‐igbp.org, receives over 1500 hits a day.
Handman and Senson receive 2003 Walter Sullivan Award For Excellence in Science Journalism—Features
Authors: McDonald Bob , Handman Jim
Published: March 2004

Patric Senson and James Handman received the Sullivan Award at AGU Fall Meeting Honors Ceremony, which was held on 10 December 2003, in San Francisco, California. The award honors “a single article or radio/television report that makes geophysical material accessible and interesting to the general public”
Navigation Principles of Positioning and Guidance
Authors: Luzum Brian
Published: March 2004

Navigation is the science of determining our position and our course of motion. Because it involves such fundamental quantities, navigation has played an essential role in human existence for millennia. This role has hardly diminished, even though we now have the capability to determine where we are with global radio navigation systems such as the Global Positioning System (GPS). If anything, the opposite is true. We are finding new ways of using navigation information to make our travels safer, faster, less costly, and generally more convenient.
Lightning Physics and Effects
Authors: Orville Richard E.
Published: March 2004

Lightning Physics and Effects is not a lightning book; it is a lightning encyclopedia. Rarely in the history of science has one contribution covered a subject with such depth and thoroughness as to set the enduring standard for years, perhaps even decades, to come. This contribution covers all aspects of lightning, including lightning physics, lightning protection, and the interaction of lightning with a variety of objects and systems as well as the environment. The style of writing is well within the ability of the technical non‐expert and anyone interested in lightning and its effects. Potential readers will include physicists; engineers working in the power industry, communications, computer, and aviation industries; atmospheric scientists; geophysicists; meteorologists; atmospheric chemists; foresters; ecologists; physicians working in the area of electrical trauma; and, lastly, architects.
General anesthetic octanol and related compounds activate wild‐type and delF508 cystic fibrosis chloride channels
Authors: Marcet Brice , Becq Frédéric , Norez Caroline , Delmas Patrick , Verrier Bernard
Published: March 2004

Cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channel is defective during cystic fibrosis (CF). Activators of the CFTR Cl− channel may be useful for therapy of CF. Here, we demonstrate that a range of general anesthetics like normal‐alkanols (n‐alkanols) and related compounds can stimulate the Cl− channel activity of wild‐type CFTR and delF508‐CFTR mutant.

The effects of n‐alkanols like octanol on CFTR activity were measured by iodide (125I) efflux and patch‐clamp techniques on three distinct cellular models: (1) CFTR‐expressing Chinese hamster ovary cells, (2) human airway Calu‐3 epithelial cells and (3) human airway JME/CF15 epithelial cells which express the delF508‐CFTR mutant.

Our data show for the first time that n‐alkanols activate both wild‐type CFTR and delF508‐CFTR mutant. Octanol stimulated 125I efflux in a dose‐dependent manner in CFTR‐expressing cells (wild‐type and delF508) but not in cell lines lacking CFTR. 125I efflux and Cl− currents induced by octanol were blocked by glibenclamide but insensitive to 4,4′‐diisothiocyanatostilbene‐2,2′‐disulfonic acid, as expected for a CFTR Cl− current.

CFTR activation by octanol was neither due to cell‐to‐cell uncoupling properties of octanol nor to an intracellular cAMP increase. CFTR activation by octanol requires phosphorylation by protein kinase‐A (PKA) since it was prevented by H‐89, a PKA inhibitor.

n‐Alkanols chain length was an important determinant for channel activation, with rank order of potencies: 1‐heptanol<1‐octanol<2‐octanol<1‐decanol. Our findings may be of valuable interest for developing novel therapeutic strategies for CF.

British Journal of Pharmacology (2004) 141, 905–914. doi:10.1038/sj.bjp.0705684
α1‐Adrenoceptor subtypes involved in vasoconstrictor responses to exogenous and neurally released noradrenaline in rat femoral resistance arteries
Authors: Zacharia Joseph , Hillier Chris , MacDonald Allan
Published: March 2004

The α1‐adrenoceptor subtypes involved in responses to exogenous and neurally released noradrenaline in rat femoral resistance arteries were characterised using a small vessel myograph, with antagonists prazosin (nonsubtype selective), 5‐methyl‐urapidil (α1A‐selective), BMY 7378 (α1D‐selective) and the alkylating agent chloroethylclonidine (preferential for α1B‐).

Prazosin and 5‐methyl‐urapidil produced rightward shifts of the exogenous noradrenaline concentration – response curve (CRC) with pA2 values of 9.2 and 9.1 respectively, in agreement with the presence of α1A‐adrenoceptors. BMY 7378 (1 μM) shifted the noradrenaline CRC with an apparent pKB of 6.7, in agreement with the presence of α1A‐, but not α1D‐, adrenoceptors. Chloroethylclonidine at 1 μM had no effect and at 10 μM produced only a small reduction (c. 20%) in the maximum response to noradrenaline, indicating little, if any, contribution from α1B‐adrenoceptors.

Responses of the rat femoral resistance arteries to electrical field stimulation (EFS) at 5–30 Hz for 10 s and 0.05 ms pulse width were principally due to α1‐adrenoceptor stimulation. Prazosin and 5‐methyl‐urapidil inhibited EFS‐mediated responses with pIC50s of 9.3 and 8.2, respectively, consistent with the α1A‐adrenoceptor being the predominant subtype. Responses to EFS at 10–30 Hz were relatively insensitive to BMY 7378 (pIC50, 6.5–6.7), while responses to 5 Hz were inhibited with a significantly higher pIC50 of 8.02, suggesting the contribution of α1D‐adrenoceptors. Chloroethylclonidine had no effect on responses to EFS, ruling out the contribution of an α1B‐subtype.

In the presence of cocaine, the predominant subtype involved in responses to EFS was the α1A‐adrenoceptor, with a contribution from α1D‐adrenoceptors at low frequency, as seen in the absence of cocaine. However, there was also a significant increase in the sensitivity to BMY 7378 at higher frequencies, suggesting that a further small α1D‐adrenoceptor component may be uncovered in the presence of cocaine.

The present study has shown a predominant role of the α1A‐adrenoceptor in contractions due to exogenous noradrenaline and to neurally released noradrenaline in rat femoral resistance arteries. α1D‐Adrenoceptors are not involved in responses to exogenous noradrenaline but appear to be activated by neurally released noradrenaline at a low frequency of stimulation and at higher frequencies in the presence of neuronal‐uptake blockade.

British Journal of Pharmacology (2004) 141, 915–924. doi:10.1038/sj.bjp.0705690
Differential regulation by AT1 and AT2 receptors of angiotensin II‐stimulated cyclic GMP production in rat uterine artery and aorta
Authors: Hannan Ruth E , Gaspari Tracey A , Davis Elizabeth A , Widdop Robert E
Published: March 2004

In the present study we determined whether angiotensin II (Ang II) could increase cyclic GMP levels in two blood vessels that exhibit markedly different angiotensin II receptor subtype expression: rat uterine artery (UA; AT2 receptor‐predominant) and aorta (AT1 receptor‐predominant), and investigated the receptor subtype(s) and intracellular pathways involved.

UA and aorta were treated with Ang II in the absence and presence of losartan (AT1 antagonist; 0.1 μM), PD 123319 (AT2 antagonist; 1 μM), NOLA (NOS inhibitor; 30 μM), and HOE 140 (B2 antagonist; 0.1 μM), or in combination.

Ang II (10 nM) induced a 60% increase in UA cyclic GMP content; an effect that was augmented with PD 123319 and HOE 140 pretreatment, and abolished by cotreatment with losartan, as well as by NOLA.

In aorta, Ang II produced concentration‐dependent increases in cyclic GMP levels. Unlike effects in UA, these responses were abolished by PD 123319 and by NOLA, whereas losartan and HOE 140 caused partial inhibition.

Thus, in rat UA, Ang II stimulates cyclic GMP production through AT1 and, to a less extent, AT2 receptors. In rat aorta, the Ang II‐mediated increase in cyclic GMP production is predominantly AT2 receptor‐mediated. In both preparations, NO plays a critical role in mediating the effect of Ang II, whereas bradykinin has differential roles in the two vessels. In UA, B2 receptor blockade may result in a compensatory increase in cyclic GMP production, whilst in aorta, bradykinin accounts for approximately half of the cyclic GMP produced in response to Ang II.

British Journal of Pharmacology (2004) 141, 1024–1031. doi:10.1038/sj.bjp.0705694
Agonist‐dependence of recovery from desensitization of P2X3 receptors provides a novel and sensitive approach for their rapid up or downregulation
Authors: Sokolova Elena , Skorinkin Andrei , Fabbretti Elsa , Masten Lara , Nistri Andrea , Giniatullin Rashid
Published: March 2004

Fast‐desensitizing P2X3 receptors of nociceptive dorsol root ganglion (DRG) neurons are thought to mediate pain sensation. Since P2X3 receptor efficiency is powerfully modulated by desensitization, its underlying properties were studied with patch‐clamp recording.

On rat cultured DRG neurons, 2 s application of ATP (EC50=1.52 μM), ADP (EC50=1.1 μM) or α,β‐meATP (EC50=1.78 μM) produced similar inward currents that fully desensitized, at the same rate, back to baseline. Recovery from desensitization was much slower after ATP and ADP than after α,β‐meATP and, in all cases, it had sigmoidal time course.

By alternating the application of ATP and α,β‐meATP, we observed complete cross‐desensitization indicating that these agonists activated the same receptors. This notion was confirmed by the similar antagonism induced by 2′, 3′‐O‐(2,4,6,trinitrophenyl)‐adenosine triphosphate (TNP‐ATP).

Recovery from desensitization elicited by ATP was unexpectedly shaped by transient application of α,β‐methylene‐adenosine triphosphate (α,β‐meATP), and vice versa. Thus, short‐lasting, full desensitization produced by α,β‐meATP protected receptors from long‐lasting desensitization induced by subsequent ATP applications. ATP and ADP had similar properties of recovery from desensitization.

Low nM concentrations of α,β‐meATP (unable to evoke membrane currents) could speed up recovery from ATP‐induced desensitization, while low nM concentrations of ATP enhanced it. Ambient ATP levels were found to be in the pM range (52±3 pM).

The phenomenon of cross‐desensitization and protection was reproduced by rP2X3 receptors expressed by rat osteoblastic cell 17/2.8 or human embryonic kidney cell 293 cells, indicating P2X3 receptor specificity.

It is suggested that transient application of an agonist that generates rapid recovery from desensitization, is a novel, powerful tool to modulate P2X3 receptor responsiveness to the natural agonist ATP.

British Journal of Pharmacology (2004) 141, 1048–1058. doi:10.1038/sj.bjp.0705701