bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of atrial fibrillation on cardiac brain natriuretic peptide release during haemodynamic stress in heart failure
Authors: Gould P.A. , D'Agostino J. , Schneider H.G. , Kaye D.M.
Published: November 2005

Background:

The determinants of release of brain natriuretic peptide (BNP) in heart failure (HF) are incompletely understood, particularly, the effect of heart rhythm and haemodynamic stress.

Aims:

To investigate the effect of haemodynamic stress on cardiac BNP release in HF and differentiate this response for atrial fibrillation (AF) and sinus rhythm (SR).

Methods:

In 18 HF patients (ejection fraction<40%, 9 in AF and 9 in SR) haemodynamics and BNP levels were measured from arterial and coronary sinus samples at baseline, after 10 min of 20° passive head up tilt (HUT) and after 10 min of isometric handgrip (IHG) exercise. From these data, we calculated a transcardiac BNP gradient and compared results between the AF and SR cohort.

Results:

During haemodynamic stress in both groups, there were no significance differences in left sided filling pressures. At baseline, there were no differences in BNP measurements between the SR and AF group. The transcardiac BNP gradient increased significantly in the SR (p=0.02) but not the AF cohort, after HUT. During IHG exercise, there was a significant decrease in cardiac BNP release in the AF cohort (p=0.03) but not the SR cohort.

Conclusion:

These data imply in HF, cardiac rhythm influences cardiac BNP release in response to haemodynamic stress.
Vasoactive intestinal peptide—release from the heart and response in heart failure due to left ventricular pressure overload
Authors: Kupari Markku , Mikkola Tomi S. , Turto Heikki , Lommi Jyri , Ylikorkala Olavi
Published: November 2005

Background:

Vasoactive intestinal peptide (VIP) is a peptidergic neurotransmitter and a vasodilator with positive inotropic and chronotropic properties. Whether and how VIP contributes to the neuroendocrine response in heart failure (HF) is disputed, and there are no data on VIP in pressure overload‐induced HF.

Methods:

We studied 129 adults with isolated aortic valve stenosis (AS). Blood was sampled from the aortic root and, in a subset of 48 patients, also from the coronary sinus for determination of VIP by radioimmunoassay. HF was diagnosed according to the European Society of Cardiology criteria.

Results:

Plasma VIP (mean±S.E.M.) was slightly higher in patients with HF (22.6±0.9 pmol/l, n=41) than in patients free of HF (21.1±0.5 pmol/l, n=88) or in 11 control patients without structural heart disease (20.0±1.3 pmol/l, n=11) (p=0.030 across the groups). VIP did not correlate with any measurement of cardiac structure or function in AS. The change in plasma VIP from aortic root to coronary sinus averaged +1.2±0.4 pmol/l in the 11 control patients (p=0.021), +1.2±0.2 pmol/l in 33 AS patients free of HF (p<0.001) and +0.8±0.3 pmol/l in 15 AS patients with HF (p=0.037).

Conclusions:

Both structurally normal and diseased hearts release VIP into the coronary sinus. Although marginally elevated in the systemic circulation, VIP is unlikely to contribute significantly to the neuroendocrine activation in HF due to pressure overload.
Climatic and sea level controls on Late Quaternary eolian activity on the Agulhas Plain, South Africa
Authors: Carr Andrew S. , Thomas David S.G. , Bateman Mark D.
Published: November 2005

Located at the interface between the temperate westerly and sub-tropical climate systems, South Africa's winter rainfall zone (WRZ) is a key location in understanding Late Quaternary atmospheric circulation dynamics. Inactive eolian deposits in the WRZ, comprising pan-fringing lunette and coastal dunes, were investigated to establish their depositional ages and utility as paleoenvironmental indicators. The resulting optical luminescence chronology reveals episodic lunette accretion at 60,000–45,000 yr, 12,000–13,000 yr, 2800–2600 yr, 1200 yr, and <1000 yr, with coastal dune ages clustering at 4100–4700 yr.

Episodes of lunette and coastal dune accretion on the Agulhas Plain are temporally distinct, reflecting differing fundamental controls on their activity. Comparisons to previously published data also reveal that the lunettes differ in age from more ancient coastal eolianites. Lunette deposition is asynchronous between locations, reflecting the topographic and hydrological setting of the individual pans. In near-coastal settings, with limited surface recharge, lunette accretion appears to be at least partially controlled by sea level induced changes in groundwater levels. Those pans with more significant surface recharge (particularly from fluvial systems) may produce less ambiguous paleoenvironmental records, with pan status more strongly reflecting regional hydrological conditions. Lunette orientation is indicative of strong westerly winds during both the Pleistocene and Holocene. Lunette accretion would have been promoted by reduced on-shore moisture transport during the summer months, enhancing rainfall seasonality. Such conditions would have been promoted by increased continentality as the Agulhas Bank was exposed during low sea level stands.
On the Frontier of The Empire of Chance: Statistics, Accidents, and Risk in Industrializing America
Authors: Mohun Arwen
Published: November 2005

In The Empire of Chance, historians of science Gigerenzer et al. argue that statistical thinking has been “second to no other area of scientific endeavor” in its influence on “modern life and thought” (Gigerenzer et al. 1989, xiv-xv). This article describes how quantitative descriptions of risk associated with industrialization and technological change became part of the mentality of ordinary Americans. It explains why Americans began counting accidents, tells what kinds of accidents they counted and how they counted them, and shows how statistical representations of risk were used to justify prescriptions for public policy and individual behavior. On this frontier of the empire of chance, safety experts and self-styled “practical statisticians” were the principal colonizers. Distant from the centers of academic statistical science, they compromised rigorous scientific standards of methodology and accurate prediction in order to make convincing arguments outside their circles of expertise. To convey their point of view to audiences who were not literate in the field of statistics, they created a public language that conveyed statistical ideas through metaphors, graphic representations, and other rhetorical devices. They also engaged non-experts in collecting and analyzing data and, by the 1920s, even used quantitative self-measurement as a device to convince members of the public to alter their own risk-taking behaviors.
Poor Taste as a Bright Character Trait: Emmy Noether and the Independent Social Democratic Party
Authors: McLarty Colin
Published: November 2005

The creation of algebraic topology required “all the energy and the temperament of Emmy Noether” according to topologists Paul Alexandroff and Heinz Hopf. Alexandroff stressed Noether's radical pro-Russian politics, which her colleagues found in “poor taste”; yet he found “a bright trait of character.” She joined the Independent Social Democrats (USPD) in 1919. They were tiny in Göttingen until that year when their vote soared as they called for a dictatorship of the proletariat. The Minister of the Army and many Göttingen students called them Bolshevist terrorists. Noether's colleague Richard Courant criticized USPD radicalism. Her colleague Hermann Weyl downplayed her radicalism and that view remains influential but the evidence favors Alexandroff. Weyl was ambivalent in parallel ways about her mathematics and her politics. He deeply admired her yet he found her abstractness and her politics excessive and even dangerous.
An Astronomical Road to General Relativity: The Continuity between Classical and Relativistic Cosmology in the Work of Karl Schwarzschild
Authors: Schemmel Matthias
Published: November 2005

In this article it is argued that a continuity exists between Karl Schwarzschild's work on foundational problems on the borderline of physics and astronomy and his later occupation with general relativity. Based on an analysis of Schwarzschild's published works as well as formerly neglected unpublished notes it is shown that, long before the rise of general relativity, Schwarzschild was concerned with problems that later became associated with that theory. In particular he considered non-Euclidean cosmologies, linked the phenomena of gravitation and inertia to the problem of the precession of Mercury's perihelion, and entertained the possibility of inertial frames rotating with respect to one another. It is argued that these earlier considerations, which reflect his interdisciplinary outlook on the foundations of the exact sciences, enabled Schwarzschild to recognize the significance of general relativity for astronomy, astrophysics, and cosmology earlier than most of his collegues and shaped his contributions to this theory.
The Science of Complexity: Epistemological Problems and Perspectives
Authors: Israel Giorgio
Published: November 2005

For several decades now a set of researches from a wide range of different sectors has been developed which goes by the name of “science of complexity” and is opposed point by point to the paradigm of classical science. It challenges the idea that world is “simple.” To the reductionist idea that each process is the sum of the actions of its components it opposes a holistic view (the whole is more than the sum of the parts). The aim of the present article is to analyze the epistemological status attributed in the science of complexity to several fundamental ideas, such as those of scientific law, objectivity, and prediction. The aim is to show that the hope of superseding reductionism by means of concepts such as that of “emergence” is fallacious and that the science of complexity proposes forms of reductionism that are even more restrictive than the classical ones, particularly when it claims to unify in a single treatment problems that vary widely in nature such as physical, biological, and social problems.
Introduction
Authors: Vangsnes Øystein Alexander , Rice Curt
Published: November 2005

Investigations of linguistic variation are interesting and important both from the point of view of theoretical linguistics and from that of social and cultural studies. This special issue of the Nordic Journal of Linguistics focuses on linguistic diversity from a theoretical perspective and presents five selected papers that combine the study of dialect data with linguistic theorizing.
What's the better move? On verb placement in Standard and Northern Norwegian
Authors: Bentzen Kristine
Published: November 2005

Northern Norwegian (NN) allows verbs to precede adverbs in non-V2 contexts, whereas in Standard Norwegian (StN) verbs have to follow adverbs. These facts are discussed with respect to three different approaches to clausal structure. NN is problematic for a head movement account (cf. Cinque 1999) because multiple verbs may precede a given adverb, leading to violations of the Head Movement Constraint. A multiple positions account (cf. Ernst 2002, Svenonius 2002) would assume that any adverb in StN and NN can be adjoined to high positions, which may be problematic with respect to scope relations. A remnant movement approach (cf. Nilsen 2003) can account for both StN and much of the NN data by means of one generalisation, but a separate generalisation is needed for finite verbs in NN. Thus, all three approaches are faced with challenges with respect to the Norwegian data. However, it is argued that the remnant movement approach seems the most promising of the three approaches.
Coda Maximisation in Northwest Saamic
Authors: Bye Patrik
Published: November 2005

The languages of the Northwest Saamic group evince a pattern of syllabification that maximises the complexity of the coda in a bimoraic stressed syllable (cf. Kiparsky 2004 on Fenno-Swedish). The coda maximisation requirement interacts with four other syllabic well-formedness constraints in a fixed ranking that regulates the sonority profile, quantity and structural complexity of the rhyme. Varying the point at which the coda maximisation requirement interleaves with the constraints in this fixed ranking generates a restrictive microtypology of coda maximisation in Northwest Saamic. The last part of the paper proposes to eliminate the stipulative fixed ordering by ranking the four syllabic well-formedness constraints in a proper inclusion (stringency) hierarchy (de Lacy 2004). It is argued that syllable rhymes may be characterised as falling on a scale of degree of perceptual integrity (dpi) and that complex codas are more dispreferred when the syllable has low dpi.
Variation in subject case marking in Insular Scandinavian
Authors: Jónsson Jóhannes Gísli , Eythórsson Thórhallur
Published: November 2005

The Insular Scandinavian (IS) languages, Icelandic and Faroese, exhibit variation in subject case marking, primarily pertaining to an older idiosyncratic case and an innovative case that instantiates a regular pattern. This variation occurs to a considerable degree at the level of the individual speaker. We argue that this intra-speaker variation in IS involves optionality within one grammar and not competition between two different grammars or dialects in the sense of Kroch (1989, 1994). Mainly on the basis of data from the so-called Dative Substitution (DS) in Icelandic, we show that this variation does not involve any kind of parameter, and that it is not the result of dialect contact, as the grammar competition analysis would entail.
Risk factors for Salmonella Enteritidis and Typhimurium (DT104 and non-DT104) infections in The Netherlands: predominant roles for raw eggs in Enteritidis and sandboxes in Typhimurium infections
Authors: DOORDUYN Y. , VAN DEN BRANDHOF W. E. , VAN DUYNHOVEN Y. T. H. P. , WANNET W. J. B. , VAN PELT W.
Published: November 2005

Since 1996 Salmonella Typhimurium DT104 salmonellosis has increased in The Netherlands. This prompted a case-control study of risk factors for salmonellosis to inform transmission routes for this phage type. Cases were laboratory-confirmed patients with a Salmonella infection and controls were selected from population registries by frequency matching for age, sex, degree of urbanization and season. Cases and controls received a questionnaire on risk factors. Of the 1171 cases, 573 (49%) responded: 245 S. Enteritidis and 232 S. Typhimurium cases (both DT104 and non-DT104), of which 58 were DT104. Of the 10250 controls, 3409 (33%) responded. Use of H2 antagonists [odds ratio (OR) 4·4, 95% CI 1·6–12·2] and proton pump inhibitors (OR 4·2, 95% CI 2·2–7·9), consumption of raw eggs (OR 3·1, 95% CI 1·3–7·4) and products containing raw eggs (OR 1·8, 95% CI 1·1–3·0) were associated with endemic S. Enteritidis infection. Risk factors for endemic S. Typhimurium infection were use of proton pump inhibitors (OR 8·3, 95% CI 4·3–15·9), occupational exposure to raw meat (OR 3·0, 95% CI 1·1–7·9), playing in a sandbox (for children aged 4–12 years) (OR 2·4, 95% CI 1·6–3·7), consumption of undercooked meat (OR 2·2, 95% CI 1·1–4·1) and use of antibiotics (OR 1·9, 95% CI 1·0–3·4). Use of proton pump inhibitors (OR 11·2, 95% CI 3·9–31·9) and playing in a sandbox (OR 4·4, 95% CI 1·8–10·7) were the only risk factors for S. Typhimurium DT104 salmonellosis. This study confirms known risk factors for salmonellosis. However, playing in a sandbox was a predominant new risk factor for S. Typhimurium salmonellosis in children [population attributable risk (PAR) 14%], and especially for S. Typhimurium DT104 (PAR 32%).
Repeated influenza vaccination of healthy children and adults: borrow now, pay later?
Authors: CARRAT F. , LAVENU A. , CAUCHEMEZ S. , DELEGER S.
Published: November 2005

A growing number of publications are recommending annual influenza vaccination of healthy children and adults. However, the long-term consequences of repeated influenza vaccination are unknown. We used a simple model of recurrent influenza infection to assess the likely impact of various repeated influenza vaccination scenarios. The model was based on a Markovian framework and was fitted on annual incidence rates of influenza infection by age. We found that natural influenza infection reduced the risk of being re-infected by 15·4% (95% confidence interval 7·1–23·0). Various scenarios of repeated influenza vaccination were then simulated and compared with a reference scenario where vaccination is given from age 65 years onwards. We show that repeated vaccination at a young age substantially increases the risk of influenza in older age, by a factor ranging between 1·2 (vaccination after 50 years) to 2·4 (vaccination from birth). These findings have important implications for influenza vaccination policies.
Risk factors for hospitalization due to respiratory syncytial virus infection among infants in the Basque Country, Spain
Authors: CILLA G. , SARASUA A. , MONTES M. , AROSTEGUI N. , VICENTE D. , PÉREZ-YARZA E. , PÉREZ-TRALLERO E.
Published: November 2005

This study analysed the role of several risk factors for hospitalization due to community-acquired, respiratory syncytial virus (RSV) infection. The risk factors detected in infants hospitalized for RSV infection in the first 24 months of life were compared with those in the general infant population in our region. There were 361 episodes of hospitalization in 357 infants. Eighty per cent of the infants did not present underlying conditions for severe RSV infection and only 10 (3%) were candidates for palivizumab prophylaxis. In multivariate analysis, birthweight of <2500 g was independently associated with hospitalization for RSV infection and was the most commonly detected medical risk factor. Other risk factors were maternal age at delivery <25 years, birth in the second half of the year, prematurity, suburban residence and congenital heart disease. In conclusion, together with well-known risk factors, we found that low birthweight was an independent factor for severe RSV infection.
Changing epidemiology of bacterial meningitis among adults in England and Wales 1991–2002
Authors: GJINI A. B. , STUART J. M. , LAWLOR D. A. , CARTWRIGHT K. A. V. , CHRISTENSEN H. , RAMSAY M. , HEYDERMAN R. S.
Published: November 2005

We examined the epidemiology of community-acquired bacterial meningitis among adults in England and Wales between 1991 and 2002. Among 3169 cases, meningococcal infection was predominant among young adults and pneumococcal meningitis among older adults. Whilst infection due to most causes decreased, the incidence of tuberculous (TB) meningitis doubled over the 12 years. The mortality rate among meningococcal and pneumococcal infections fell from 0·45/105 to 0·31/105 (P=0·0001). This study demonstrates important changes in the epidemiology of bacterial meningitis among UK adults. Improvements in clinical management, childhood vaccination programmes and the re-emergence of tuberculosis are likely to be drivers of these changes.
Protecting China's children: valuing the health impacts of reduced air pollution in Chinese cities
Authors: MEAD ROBERT W. , BRAJER VICTOR
Published: November 2005

As China advances its overall program of economic development, many Chinese cities consistently suffer from unhealthy levels of air pollution. One of the groups most affected is children. This paper provides some quantification regarding the extent of various morbidity costs upon children in portions of urban China. Using China-based health-effects and valuation studies, the authors project, and value in dollar figures, the number of averted cases of childhood colds, bronchitis, asthma, and respiratory-related hospital visits resulting from a lowering of air pollution levels. The results indicate that these child morbidity benefits may be substantial, with a mid-range value of nearly $3.5 billion over the period 2002–2011.
Efficiency and equity in groundwater markets: the case of Madhya Pradesh, India
Authors: KAJISA KEI , SAKURAI TAKESHI
Published: November 2005

This paper examines efficiency and equity in groundwater markets with special attention to output sharing contracts and to the bargaining relationships between sellers and buyers, using household level data from Madhya Pradesh, India. Regression results find no significant inefficiency on farms managed by output sharing buyers, presumably because optimal input intensities are achieved through effective monitoring and contract adherence mechanisms embedded in long-term and intensive personal relationships between sellers and buyers. As for equity, the finding is that, while output sharing buyers pay higher water prices, the rate of premiums is merely 5 percentage points higher than the informal interest rate that they would have had to carry under other types of groundwater contracts. The results also show that buyers who have access to alternative water sellers pay lower water prices. These findings indicate that if the imperfection of credit and contingent markets in rural areas are taken into account, informal groundwater markets work fairly well in agrarian communities if monitoring and contract adherence mechanisms are embedded and a sufficient number of potential sellers are available.
Willingness to pay for water and location bias in hedonic price analysis: evidence from the Indonesian housing market
Authors: YUSUF ARIEF ANSHORY , KOUNDOURI PHOEBE
Published: November 2005

Hedonic valuation of quality attributes can be misleading when the assumption that these attributes are exogenous to sample selection is violated. This paper considers the simultaneity between hedonic valuation and sample selection in the context of a model of consumer behavior over packaged goods and investigates empirically how the decision on house location (urban/rural) affects the household's valuation of water-related characteristics of the house in question. The empirical analysis uses data from the Indonesian housing market and suggests that households value access to safe and improved domestic water sources. However, failing to correct for sample selection results in a biased valuation of willingness to pay for house characteristics. This might misguide policy recommendations for improved provision of domestic water, based on cost–benefit analysis.
Productive efficiency, property rights, and sustainable renewable resource development in the mini-purse seine fishery of the Java Sea
Authors: SUSILOWATI INDAH , BARTOO NORMAN , OMAR ISHAK HAJI , JEON YONGIL , KUPERAN K. , SQUIRES DALE , VESTERGAARD NIELS
Published: November 2005

The relationship between productive efficiency and sustainable development of fishing industries in developing countries has received little attention. Ill-structured property rights in common-pool resources lead to a contradiction between private and social technical efficiency, with private and social costs dependent on the level of technical efficiency. Development policies that increase private efficiency can increase the social cost with ill-structured property rights and common-pool resources, and thereby increase social inefficiency. This paper examines this relationship through a case study of the mini purse seine fishery of the Java Sea, and finds that private technical efficiency does not depend on any measurable attributes of human capital, diverges substantially between the peak and off seasons, and differs between vessels more within the off season.
Insight into the Neogene tectonic history of the northern Bolivian Orocline from new paleomagnetic and geochronologic data
Authors: Rousse Sonia , Gilder Stuart , Fornari Michel , Sempere Thierry
Published: November 2005

A paleomagnetic study of 36 sites (315 samples) of Neogene strata from the Peruvian Altiplano and adjacent sub‐Andean belt (Pilcopata area), combined with 40Ar/39Ar dating of 13 lava flows, provide new constraints on the Cenozoic deformation history of the northern Bolivian Orocline. In the Peruvian Altiplano, 40Ar/39Ar dating brackets the age of the strata sampled for paleomagnetism between 26.5 and 12.1 Ma for the Huaccochullo basin, 18.6 and 12.1 Ma for the Descanso‐Yauri basin, and 16.8 and 15.5 Ma for the Ayaviri basin. Sub‐Andean sediments are paleontologically constrained as Miocene, yet pre‐9 Ma. Prefolding magnetizations isolated in the Huaccochullo, Descanso‐Yauri, and Pilcopata localities indicate significant counterclockwise vertical axis block rotations of 11.3° ± 5.4°, 31.0° ± 10.2° and 7.8° ± 4.8°, respectively. The pattern of rotations together with mapped structures suggest that deformation of the northern Altiplano was partitioned into large regions experiencing relatively minor rotation versus smaller, isolated basins exhibiting high‐amplitude counterclockwise rotations that lie in a major left‐lateral shear zone. Our new results imply significant transpressional deformation occurred throughout the Peruvian Altiplano since circa 12 Ma and are integrated in a model detailing the tectonic evolution of the northern Bolivian Orocline since 25 Ma.
North Sea storm surge statistics based on projections in a warmer climate: How important are the driving GCM and the chosen emission scenario?
Authors: Woth Katja
Published: November 2005

Climate models, simulating the effect of plausible future emission concentrations (scenarios), describe for the future an increase of high wind speeds over Northwest Europe during winter. With the help of a hydrodynamic model of the North Sea, these atmospheric future conditions are used to project storm surge heights for the Northwest European Shelf Sea. Four different projections are presented, all generated with the same Regional Climate Model, which itself is driven with two different Global Climate Model scenarios both exposed to two different emission scenarios. The analyses are carried out for a 30‐year time‐slice at the end of the 21st century. All four ensemble members point to a significant increase of storm surge elevations for the continental North Sea coast of between 15 and almost 25 cm. However, the different storm surge projections are not statistically distinguishable from each other but can provide a range of possible evolutions of surge extremes in a warmer climate.
Viscosity of high crystal content melts: Dependence on solid fraction
Authors: Costa Antonio
Published: November 2005

The rheological properties of suspensions containing high solid fractions are investigated. Attention is focused on viscosity of silicate and magmatic melt systems. A general empirical equation which describes the relative viscosity of suspensions as a function of suspended solid fraction is proposed. In the limit of very dilute solid concentrations it reduces to the Einstein equation. The proposed relationship is satisfactorily applied to reproduce available experimental data relative to silicate melts. Moreover, the extrapolation of the model to very high concentrations is compared with experimental observations on partially‐melted granite.
Understanding different precipitation seasonality regimes from water vapor and temperature fields: Case studies
Authors: Lu Er , Zeng Xubin
Published: November 2005

Different precipitation seasonality regimes, although produced by different surface and atmospheric conditions, can be understood from the basic atmospheric fields. By comparing the change of water vapor from winter to summer with the change of temperature using the NARR reanalysis, three seasonality cases over the United States and Mexico are analyzed. In the western coast of the U.S., the change of temperature from winter to summer is much greater than the change of water vapor. So, relative to summer, the coldness of the winter air is much more significant than the dryness, which makes the winter have a large saturation extent and thus precipitation. In contrast, over South Mexico, the much more significant moistness of the summer air than its warmness is important to the summer monsoon precipitation. In the southeastern U.S. where precipitation occurs throughout the year, the changes of water vapor and temperature are roughly equivalent.
Comment on “Are there internal Kelvin waves in Lake Tanganyika?” by Jaya Naithani and Eric Deleersnijder
Authors: Antenucci Jason P.
Published: November 2005

Recent numerical modelling efforts have demonstrated the presence of Kelvin waves in Lake Tanganyika (Naithani and Deleersnijder, 2004), however it is claimed that these waves should not appear according to classical scaling arguments. Based on existing classical scaling arguments, supported by laboratory and field investigations, I will show why they can, and apparently do, appear in Lake Tanganyika.
Rapid retreat and acceleration of Helheim Glacier, east Greenland
Authors: Howat I. M. , Joughin I. , Tulaczyk S. , Gogineni S.
Published: November 2005

A significant amount of the measured coastal thinning of the Greenland ice sheet may be due to recent acceleration of outlet glaciers. Using remote sensing, we measured two major periods of speedup on Helheim Glacier between 2000 and 2005 that increased peak speeds from approximately 8 to 11 km/yr. These speedups coincided with rapid retreats of the calving front, totaling over 7.5 km. The glacier also thinned by over 40 m from 2001 to 2003. Retreat of the ice front appears to decrease resistance to flow and concentrates the gravitational driving force over a smaller area. Farther up‐glacier, acceleration may be a delayed response to surface draw‐down and steepening of the glacier's main trunk. If the 2005 speedup also produces strong thinning, then much of the glacier's main trunk may un‐ground, leading to further retreat.
Reconstruction of the reconnection rate from Cluster measurements: First results
Authors: Semenov V. S. , Penz T. , Ivanova V. V. , Sergeev V. A. , Biernat H. K. , Nakamura R. , Heyn M. F. , Kubyshkin I. V. , Ivanov I. B.
Published: November 2005

A model of transient time‐dependent magnetic reconnection is used to describe the behavior of nightside flux transfers (NFTEs) in the Earth's magnetotail. On the basis of the analytical approach to reconnection developed by Heyn and Semenov (1996) and Semenov et al. (2004a) we calculate the magnetic field and plasma bulk velocity time series observed by a satellite. The solution for the plasma parameters is given in the form of a convolution integral. The calculation of the reconnection electric field is an ill‐posed inverse problem, which we treat in the frame of the theory of regularization. This method is applied to Cluster measurements from 8 September 2002, where a series of earthward propagating 1‐min scale magnetic field and plasma flow variations are observed outside of the plasma sheet, which are consistent with the theoretical picture of NFTEs. We analyzed three NFTEs and reconstructed the reconnection electric field. Additionally, the position of the satellite with respect to the reconnection site as well as the Alfvén velocity are estimated because they are necessary input parameters for the model. The reconnection electric field is found to be about 1–2 mV/m, while the reconnection site is located about 29–31 RE in the magnetotail.
Nucleation process with dilatant hardening on a fluid‐infiltrated strike‐slip fault model using a rate‐ and state‐dependent friction law
Authors: Shibazaki Bunichiro
Published: November 2005

Dilatancy and fluid movements in a fault zone significantly affect the mode of the nucleation process and are one of the key factors for understanding the physical mechanisms of some short‐term precursory phenomena. We investigated a model of the earthquake nucleation processes on a vertical fluid‐infiltrated strike‐slip fault in a three‐dimensional elastic half‐space using a Dieterich/Ruina rate‐ and state‐dependent friction law and an evolution equation for plastic porosity. Because of dilatancy, porosity is thought to increase with slip velocity. We assume that plastic porosity depends logarithmically on the state variable in the friction law. The results of numerical simulations show that porosity in the fault zone increases with increasing slip velocity in the nucleation zone. Then pore fluid pressure in the fault zone drops significantly, resulting in dilatant hardening. With increasing dilatancy coefficient ɛ or with decreasing pore compressibility βφ, larger pore fluid pressure drop is observed during the nucleation process, which in turn increases the size of the nucleation zone. We observe that when a dilatancy coefficient ɛ is large, a quasi‐static nucleation zone extends widely with a low stress drop. Finally, slip velocity is accelerated in a localized area in the quasi‐static nucleation zone, which is a place where a dynamic rupture originates. The size of the accelerated slip zone is significantly smaller than that of the quasi‐static nucleation zone. Numerical results using a larger dilatancy coefficient can explain the extension of foreshock activity, which is occasionally observed in large earthquakes.
A modeling study of the response of tropical deep convection to the increase of cloud condensation nuclei concentration: 2. Radiation and tropospheric chemistry
Authors: Wang Chien
Published: November 2005

Following the discussion in a previous companion paper on the responses of cloud dynamics and microphysics to the changes in initial concentration of aerosols suitable of serving as cloud condensation nuclei (CCN0), the consequent impacts of these responses on cloud radiative effect and tropospheric chemistry are studied using a three‐dimensional cloud‐resolving model. The radiative forcings of modeled cloud are found to generally increase with CCN0. This increase with CCN0 is more closely correlated to the changes in cloud coverage rather than other cloud properties. The enhanced convective strength of the modeled cloud with CCN0 affects the redistributions of chemical species including aerosols and water vapor. These impacts include an enhanced moistening of cloudy air while drying outside, an increase in the abundance of slowly soluble gases such as CO in the upper troposphere, and a simultaneous low availability of soluble gases attributed to the enhanced scavenging by cloud droplets. Additionally, the heterogeneous uptake of chemical species by ice particles is found to largely relate to the origins of these species and this uptake is also influenced by the changes in CCN0. Although the impacts of cloud on photochemistry are significant, these impacts appear to be not very sensitive to the changes in CCN0, caused primarily by the thick cloud layer in the modeled case.
A three‐dimensional model study of the effect of new temperature‐dependent quantum yields for acetone photolysis
Authors: Arnold S. R. , Chipperfield M. P. , Blitz M. A.
Published: November 2005

We have used the TOMCAT three‐dimensional chemical transport model (CTM) to investigate the impact of recent laboratory measurements of the temperature dependence of the acetone photolysis quantum yield on global tropospheric chemistry. The new acetone quantum yields cause a significant decrease in the calculated acetone loss rate in troposphere. The annual global mean photolysis loss of acetone is reduced by a factor of ∼2, making OH oxidation the dominant acetone sink. Photolysis rates decrease by between ∼80 and 90% in the cold upper troposphere (UT). The atmospheric lifetime of acetone increases from 22 to 35 days, with an increase in the global burden from 2.6 to 4.1 Tg. This is maintained through a global source strength of 42.5 Tg/yr, which is approximately half of that inferred by some previous model studies. Comparisons of modeled and observed acetone profiles from the remote tropical Pacific demonstrate much improved agreement with the new quantum yields, with a reduction in the model bias relative to aircraft observations from −50 to −17%. With the new quantum yields, modeled peroxyacetylnitrate (PAN) decreases in the UT and throughout the Northern Hemisphere. PAN increases are modeled in Southern Hemisphere, as the increases in acetone outweigh the slower rate of peroxyacetyl production. The new quantum yields reduce the model HOx(=OH + HO2) throughout the troposphere. The locations of largest changes to HOx and the OH:HO2 ratio, caused by changes in NOx, mean the impact on model global OH is small (−0.5%). The net effect of using the new quantum yields on tropospheric ozone is also small; the model predicts a maximum 1% decrease in the Northern Hemisphere lower troposphere.
Scenarios for the evolution of life on Mars
Authors: Schulze‐Makuch Dirk , Irwin Louis N. , Lipps Jere H. , LeMone David , Dohm James M. , Fairén Alberto G.
Published: November 2005

As the environmental histories of Earth and Mars have diverged drastically after the first few hundred million years, so would the history of any life on them. While Earth has had liquid water on its surface for billions of years, Mars most likely had long dry and cold environments interspersed with warmer and wetter periods. Life thrived on Earth but may have been severely restricted on Mars. There it could be present today in liquid water in or beneath ice sheets or glaciers, in subterranean aqueous reservoirs, especially in regions of elevated heat flow, or in protected habitats such as lava tubes, caves, or cracks and fissures. The potential for life is enhanced in regions where elevated heat flow may occur, such as in parts of the Tharsis and Elysium volcanic provinces. Possible organisms would be chemoautotrophic psychrophiles adapted to a nutrient‐poor environment or photoautotrophic life in selected near‐surface habitats. Alternatively, life may have evolved alternating cycles between active and dormant forms, in which case microbes could be present in dormant forms close to the surface and in active forms in protected environments. Periodic liquid water on Mars could have provided opportunities for biologic activity, as well as evolutionary progress, at the surface during the short‐lived climatic perturbations. Ancient organisms from any of these environments may also have left a detectable fossil record.
Ultraviolet to near‐infrared absorption spectrum of carbon dioxide ice from 0.174 to 1.8 μm
Authors: Hansen Gary B.
Published: November 2005

A laboratory experiment was devised to measure transmission at fine spectral resolution through thick, high‐quality samples of CO2 ice over an extended wavelength range. The absorption coefficient throughout the ultraviolet and near‐infrared spectral ranges 0.174–1.8 μm (5555–57,470 cm−1 in wave number) is presented here. CO2 ice samples were grown at a temperature of 150 K, typical of the Martian polar caps. The path length of the samples varied from 1.6 to 107.5 mm, allowing the measurement of absorption from <0.1 to 4000 m−1. The experiment used both a grating monochromator (with spectral resolution 0.1–0.3 nm) and a Fourier transform spectrometer (with an effective resolution of <1.0 cm−1). The transmission data for five thicknesses are used to estimate both the scattering losses for each sample and the absorption coefficient at each wavelength. The uncertainty in the most transparent wavelength regions (<10 m−1) is due to scattering extinction. Measurement noise and data scatter produce significant uncertainty only where absorption coefficients exceed 1000 m−1. Between 1.0 and 1.8 μm there are several weak to moderate absorption lines. Only an upper limit to the absorption can be determined in many places; e.g., the absorption from ∼0.25 to 1.0 μm is below the detection limit. The estimated visible absorption, ∼10–2 m−1, is a factor of 1000 smaller than the values reported by Egan and Spagnolo, which have been used previously to compute albedos of CO2 snow. The new results should be useful for studies of the seasonal polar caps of Mars.
Estimation of field‐scale soil hydraulic and dielectric parameters through joint inversion of GPR and hydrological data
Authors: Kowalsky M. B. , Finsterle S. , Peterson J. , Hubbard S. , Rubin Y. , Majer E. , Ward A. , Gee G.
Published: November 2005

A method is described for the joint use of time‐lapse ground‐penetrating radar (GPR) travel times and hydrological data to estimate field‐scale soil hydraulic parameters. We build upon previous work to take advantage of a wide range of cross‐borehole GPR data acquisition configurations and to accommodate uncertainty in the petrophysical function, which relates soil porosity and water saturation to the effective dielectric constant. We first test the inversion methodology using synthetic examples of water injection in the vadose zone. Realistic errors in the petrophysical function result in substantial errors in soil hydraulic parameter estimates, but such errors are minimized through simultaneous estimation of petrophysical parameters. In some cases the use of a simplified GPR simulator causes systematic errors in calculated travel times; simultaneous estimation of a single correction parameter sufficiently reduces the impact of these errors. We also apply the method to the U.S. Department of Energy (DOE) Hanford site in Washington, where time‐lapse GPR and neutron probe (NP) data sets were collected during an infiltration experiment. We find that inclusion of GPR data in the inversion procedure allows for improved predictions of water content, compared to predictions made using NP data alone. These examples demonstrate that the complimentary information contained in geophysical and hydrological data can be successfully extracted in a joint inversion approach. Moreover, since the generation of tomograms is not required, the amount of GPR data required for analyses is relatively low, and difficulties inherent to tomography methods are alleviated. Finally, the approach provides a means to capture the properties and system state of heterogeneous soil, both of which are crucial for assessing and predicting subsurface flow and contaminant transport.
[32P]2‐iodo‐N6‐methyl‐(N)‐methanocarba‐2′‐deoxyadenosine‐3′,5′‐bisphosphate ([32P]MRS2500), a novel radioligand for quantification of native P2Y1 receptors
Authors: Houston Dayle , Ohno Michihiro , Nicholas Robert A , Jacobson Kenneth A , Harden T Kendall
Published: November 2005

Analysis of the P2Y family of nucleotide‐activated G‐protein‐coupled receptors has been compromised by the lack of selective high‐affinity, high‐specific‐radioactivity radioligands. We have pursued quantification of the P2Y1 receptor through the development of a series of selective P2Y1 receptor antagonists.

Recently, we synthesized 2‐iodo‐N6‐methyl‐(N)‐methanocarba‐2′‐deoxyadenosine 3′,5′‐bisphosphate (MRS2500), a selective, competitive antagonist that exhibits a Ki of 0.8 nM in competition‐binding assays with [3H]MRS2279. A 3′‐monophosphate precursor molecule, MRS2608, was radiolabeled at the 5′ position with 32P using polynucleotide kinase and [γ32P]ATP to yield [32P]MRS2500.

[32P]MRS2500 bound selectively to Sf9 insect cell membranes expressing the human P2Y1 receptor (Sf9‐P2Y1), but did not detectably bind membranes expressing other P2Y receptors. P2Y1 receptor binding to [32P]MRS2500 was saturable with a KD of 1.2 nM. Agonists and antagonists of the P2Y1 receptor inhibited [32P]MRS2500 binding in Sf9‐P2Y1 membranes with values in agreement with those observed in functional assays of the P2Y1 receptor.

A high‐affinity binding site for [32P]MRS2500 (KD=0.33 nM) was identified in rat brain, which exhibited the pharmacological selectivity of the P2Y1 receptor. Distribution of this binding site varied among rat tissues, with the highest amount of binding appearing in lung, liver, and brain. Among brain regions, distribution of the [32P]MRS2500 binding site varied by six‐fold, with the highest and lowest amounts of sites detected in cerebellum and cortex, respectively.

Taken together, these data illustrate the synthesis and characterization of a novel P2Y1 receptor radioligand and its utility for examining P2Y1 receptor expression in native mammalian tissues.

British Journal of Pharmacology (2006) 147, 459–467. doi:10.1038/sj.bjp.0706453
Signaling mechanism of thrombin‐induced gingival fibroblast‐populated collagen gel contraction
Authors: Jeng Jiiang‐Huei , Lan Wan‐Hong , Wang Juo‐Song , Chan Chiu‐Po , Ho Yuan‐Soon , Lee Po‐Hsuen , Wang Ying‐Jen , Wang Tong‐Mei , Chen Yi‐Jane , Chang Mei‐Chi
Published: November 2005

Thrombin is activated during gingival tissue injury and inflammation. Thrombin (platelet)‐rich plasma has been used for periodontal regeneration with success. Thrombin and other bacterial proteases also affect the functions of adjacent periodontal cells via stimulation of protease‐activated receptors (PARs).

We noted that thrombin (0.1–2 U ml−1), human, and frog PAR‐1 agonist peptide (20–240 μM) induced the gingival fibroblast (GF)‐populated collagen gel contraction within 2 h of exposure. However, PAR‐2, PAR‐3, and PAR‐4 agonist peptide (20–240 μM) showed little effect on collagen gel contraction. U73122 (phospholipase C inhibitor) and 2‐APB (IP3 antagonist) were effective in inhibition of GF contraction.

Thrombin‐induced GF contraction was inhibited by 5 mM EGTA (an extracellular calcium chelator) and verapamil (an L‐type calcium channel blocker). In addition, W7 (10 and 25 μM, a calcium/calmodulin (CaM) inhibitor), ML‐7 (50 μM, myosin light chain kinase (MLCK) inhibitor), and HA1077 (100 μM, Rho kinase inhibitor) completely inhibited the thrombin‐induced collagen gel contraction. Thrombin also induced the phosphorylation of ERK1/ERK2 and elevated the Rho‐GTP levels in GF.

However, U0126 only partially inhibited the thrombin‐induced GF contraction. Similarly, wortmannin (100 nM), LY294002 (20 μM) (two PI3K inhibitor) and genistein also showed partial inhibition. Moreover, NAC was not able to suppress the GF contraction, as supported by the slight decrease in reactive oxygen species production in GF by thrombin.

Thrombin also stimulated metalloproteinase‐2 (MMP‐2) and MMP‐3 production in GF. But addition of GM6001 or 1,10‐phenanthroline, two MMP inhibitors, could not inhibit the thrombin‐induced GF contraction.

These results indicate that thrombin is crucial in the periodontal inflammation and wound healing by promoting GF contraction. This event is mainly mediated via PAR‐1 activation, PLC activation, extracellular calcium influx via L‐type calcium channel, and the calcium/CaM–MLCK and Rho kinase activation pathway.

British Journal of Pharmacology (2006) 147, 188–198. doi:10.1038/sj.bjp.0706462
Bv8, the amphibian homologue of the mammalian prokineticins, induces a proinflammatory phenotype of mouse macrophages
Authors: Martucci Cataldo , Franchi Silvia , Giannini Elisa , Tian Hui , Melchiorri Pietro , Negri Lucia , Sacerdote Paola
Published: November 2005

The small protein Bv8, isolated from the amphibian skin, belongs to a novel family of secreted proteins linked to several biological effects. We describe the expression of Bv8/prokineticins and their receptors in mouse macrophages, and characterize their proinflammatory activities.

The rodent analogue of Bv8, prokineticin‐2, is expressed by macrophages, as well as its G‐protein‐coupled receptor prokineticin receptor (PKR‐1 and PKR‐2). PKR‐1 is expressed more abundantly.

Bv8 induces potent chemotaxis of macrophages at concentrations as low as 10−12 M.

It stimulates lipopolysaccharide‐induced production of the proinflammatory cytokines IL‐1 and IL‐12, reducing that of the anti‐inflammatory cytokine IL‐10. The effects are observed starting at the very low concentration of 10−11 M.

Effects on chemotaxis and cytokine are not pertussis‐toxin sensitive, but are completely prevented by addition of the phospholipase inhibitor U73122, suggesting a Gq protein is involved in the Bv8‐induced effects.

Studies in PKR‐1 knockout mice indicate that all the activities exerted by Bv8 on macrophages are mediated by the PKR‐1 receptor.

In conclusion, Bv8 appears to be able to induce the macrophage to migrate and to acquire a proinflammatory phenotype.

British Journal of Pharmacology (2006) 147, 225–234. doi:10.1038/sj.bjp.0706467