bluuebunny/crossref_metadata_2025 huggingface dataset:
A review of Hand Surgery Provision in England.
Authors: HOBBY J. L. , DIAS J. J.
Published: December 2005

This study reviews hand surgical activity and the resources available for provision of hand surgery in England in 2001. Operation rates for three common procedures, viz. carpal tunnel release, Dupuytren’s surgery and ganglion surgery, were considered. The local population and the number of hand surgeons in each NHS Hospital Trust were compared. We identified 275 consultant surgeons with an interest in hand surgery working in the NHS in England. Approximately two-thirds were orthopaedic surgeons, almost one-third were plastic surgeons and a small number were accident and emergency surgeons. Half of all hand surgeons worked in large units, with three or more hand surgeons, but almost 20% of hand surgery was delivered in hospitals in which there was no surgeon with a declared interest in hand surgery. Surgery rates for Dupuytren’s contracture varied from 0.04 to 0.36 cases per 1,000 population per annum and for carpal tunnel syndrome varied from 0.25 to 1.31 cases per 1,000 per annum. We found a correlation between rates of surgery and the number of hand surgeons, locally. A recent audit ( Burke, Dias, Heras-Pelou, Bradley, & Wildin, 2004 . Providing care for hand disorders, a reappraisal of need. Journal of Hand Surgery, 29B: 575–579.) has suggested that one hand surgeon is required to meet the needs of a population of 125,000, with a national requirement for 393 hand surgeons. We conclude that there are insufficient hand surgeons in England and believe that the wide local variations in hand surgery rates are indicative of a significant unmet demand for hand surgery in the English population.
Schwannomatosis: Multiple Schwannomas of the Upper Limb
Authors: HASHAM S. , MATTEUCCI P. , STANLEY P. R. W.
Published: December 2005

Schwannomas (also known as neurilemmomas) are neoplasms of the peripheral nerve sheaths. They are the most common benign tumour of peripheral nerves, yet they account for only 5% of all soft tissue tumours. Their incidence in the upper limb is variable, as is their clinical presentation.

We present an unusual case of multiple schwannomas in the upper limb so that other surgeons can share our experience and suggest the correct diagnosis when confronted with a similar case.
Sonographically Assisted Percutaneous Release of the A1 Pulley: A New Surgical Technique for Treating Trigger Digit
Authors: JOU I. M. , CHERN T. C.
Published: December 2005

This study introduces a sonographically assisted percutaneous technique for releasing trigger digits which provides direct visualization of the release and avoids the risks of incomplete release and injury to adjacent neurovascular structures associated with other percutaneous release techniques. The “safe zone” and an estimate of the size of the A1 pulley were determined in a separate cadaver study. We then used these landmarks in a prospective clinical study of 107 digits in 83 consecutive patients treated by this technique. During the follow-ups of between 9 and 15 months, we evaluated 104 digits in 80 patients. Pain was absent in 101 digits (97%) and considerably improved in the other three (3%). All mechanical problems had been resolved and none recurred during follow-up. This technique allows the surgeon to see and monitor, precisely, the percutaneous division of the A1 pulley without open surgery and, therefore, to avoid the inherent risks of percutaneous and open surgical release.
Bipolarity in reactions to operational ‘constraints’: OM bugs under an OB lens
Authors: Bendoly Elliot , Hur Daesik
Published: December 2005

In the 1980 inaugural issue of the Journal of Operations Management, Powell and Johnson stressed the need to introduce behavioral factors into research models of operational processes and performance. While some progress has been made since then, contemporary authors argue that limited dialogue between operations management and behavioral researchers continues to restrict the interpretability of such studies. Drawing on expertise from both operations and behavioral research, and motivated by a case example, we intend to further this dialogue. In doing so, we outline interdisciplinary commonalities and several methodological pitfalls that those studying the links between resource constraints and operational performance should take into account when developing new research. These issues range from appropriate model conceptualization to operationalization for empirical studies. Recommendations for appropriately confronting methodological concerns related to these issues are provided.
Supplier integration—Finding an optimal configuration
Authors: Das Ajay , Narasimhan Ram , Talluri Srinivas
Published: December 2005

There has been increased interest in supplier integration in recent years, much of it supporting such initiatives in organizations. We operationalize supplier integration as a bundle of practices that include a set of “internal” and “external” practices. We hypothesize that such practices in specific configurations can be as important a source of performance differentials as the adoption of individual practices themselves. We theorize the existence of a level of integration that results in optimal performance. The paper uses data from a cross‐section of more than 300 US manufacturing companies to test the notion of an optimal level of supplier integration, and examine the conditions surrounding its development. The results provide empirical support for the concept of an optimal set of supplier integration practices. We show that deviations from the optimal profile are associated with performance deterioration, and that indiscriminate and continued investments in integration may not yield commensurate improvements in performance.
Exploring the efficacy of healthcare quality practices, employee commitment, and employee control
Authors: Gowen Charles R. , Mcfadden Kathleen L. , Hoobler Jenny M. , Tallon William J.
Published: December 2005

This exploratory study examines healthcare quality program practices, employee commitment and control initiatives, and perceived results by surveying the directors of hospital quality programs. U.S. hospitals are renowned to be among the highest in quality, but recent studies assert that the majority of error‐related deaths per year are preventable. In response, healthcare organizations have adopted quality management programs. Employee commitment and control theories propose that employee initiatives are critical to patient safety. However, little research has focused on the efficacy of employee commitment and control initiatives for quality programs at healthcare organizations. This study examines the responses from Quality and Risk Directors of 372 U.S. hospitals. The results of structural equation modeling (SEM) demonstrate that perceived quantitative and qualitative quality program results are more highly related to employee commitment and control initiatives than they are related to quality practices.
Medical Student Selection of Otolaryngology‐Head and Neck Surgery as a Specialty: Influences and Attitudes
Authors: McCaffrey Judith Czaja
Published: December 2005

OBJECTIVES

1) To determine factors students perceive as influential in decision to pursue otolaryngology; 2) to determine perception of importance of factors used for resident selection and individual student commitment to the match; and 3) to identify exposure to various subspecialties within otolaryngology.

DESIGN

Population survey.

METHODS

A survey was administered to students applying for otolaryngology between 2000 and 2003 at a single institution.

RESULTS

Ninety‐six students were interviewed. Seventy‐eight percent believed that the main factor influencing their decision to pursue otolaryngology was their exposure to the residents. Board scores and one‐on‐one interviews were important factors in selection of interviewees and ranking process. Interestingly, over 20% of students believed that the match should not be early because they wanted more time to commit to ENT.

CONCLUSIONS

These data underscore the importance that residents have in directing future students to our specialty. Results of the match survey may indicate an attrition rate within residency programs that may be avoided if ENT were part of the “regular” match.

EBM RATING

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Endogamy and Social Class in History: An Overview
Authors: van Leeuwen Marco H.D. , Maas Ineke
Published: December 2005

The social identities of marriage partners [...] are among the most sensitive and acute indicators of community or class feelings. Who marries whom, without courting alienation or rejection from a social set, is an acid test of the horizons and boundaries of what each particular social set regards as tolerable and acceptable, and a sure indication of where that set draws the line of membership.
Deciding Whom to Marry in a Rural Two-Class Society: Social Homogamy and Constraints in the Marriage Market in Rendalen, Norway, 1750–1900
Authors: Bull Hans Henrik
Published: December 2005

This article presents the findings of a long-term study of social homogamy in the rural community of Rendalen, Norway, in the eighteenth and nineteenth centuries. Prior to 1870, the occupation of parents was not normally recorded in the Norwegian parish registers. It is therefore difficult to carry out historical studies of social homogamy in Norway over any length of time. The Rendalen database, however, provides this information from several other sources. Structural changes over time, which led to an increase in the number of farm workers, reduced the degree of homogamy among farmers as well as creating a larger marriage market for the farm workers, thereby increasing homogamy among these farm workers. Controlling for these structural changes, it is clear that social boundaries between farmers and farm workers prevailed at least until the end of the nineteenth century. Using a multivariate analysis, we are able to identify different family characteristics that led young men and woman to marry homogamously. The farmers, especially, exerted influence on their eldest sons to marry farmers' daughters, but the role of the father in the mating process also secured more economically viable partners for the other children too.
“We Have No Proletariat”: Social Stratification and Occupational Homogamy in Industrial Switzerland, Winterthur 1909/10–1928
Authors: Schumacher Reto , Lorenzetti Luigi
Published: December 2005

The aim of this study is to examine, by analysing marital origin-related homogamy and mobility, the fluidity of a system of social stratification marked by a heterogeneous working class and likely to lead to increasing social-group solidarity during the phase of a more active labour movement in the early twentieth century. Data from Winterthur, a Swiss town characterized by the expansion of an important engineering industry, reveal that occupational homogamy was most pronounced at the top, among higher managers and professionals, and at the bottom of the social hierarchy, among unskilled factory workers. There is no empirical evidence of increased homogamous behaviour after the nationwide general strike of 1918, which is said to have had a long-term impact on workers' class-consciousness. Our analyses show, however, that the association between the social background of spouses depended on their geographical origin. This result may point to a regionally determined class-consciousness.
Pyrenean Marriage Strategies in the Nineteenth Century: The French Basque Case
Authors: Arrizabalaga Marie-Pierre
Published: December 2005

Marriage strategies in the rural Basque country of the nineteenth century differed according to social background and gender. Propertied families had more diversified strategies than landless families as a result of persistent single inheritance practices, population growth, urbanization, and industrialization which generated massive emigration. Propertied families helped some of their children to settle in local rural villages and others to emigrate to cities (women) or to America (men). Landless families, by contrast, continued to settle most of their children in local rural villages, others emigrating to America only later in the century, avoiding the cities at all cost. Men, no matter their social background, benefited the most from new economic opportunities because most of them married into families of equal or higher status. Women, by contrast, did not have equal opportunities because few married upward and outside their professional group. When women did not marry within their socio-professional group or remain single, they married into families of lower status (more often than men).
Migration, Occupational Identity, and Societal Openness in Nineteenth-Century Belgium
Authors: Van de Putte Bart , Oris Michel , Neven Muriel , Matthijs Koen
Published: December 2005

This article examines social heterogamy as an indicator of “societal openness”, by which is meant the extent to which social origin, as defined by the social position of one's parents, is used as the main criterion for selection of a marriage partner. We focus on two topics. The role first of migration and then of occupational identity in this selection of a partner according to social origin. And in order to evaluate the true social and economic context in which spouses lived, we do not use a nationwide sample but rather choose to examine marriage certificates from eleven cities and villages in Belgium, both Flemish and Walloon, during the nineteenth century. By observing different patterns of homogamy according to social origin we show in this article that partner selection was affected by the relationship between migration, occupational identity and class structure. It seems difficult to interpret all these divergent patterns in terms of modernization. In our opinion the historical context creates a complicated set of conditions reflected in differences in the type and strength of migration and in the sectoral composition and evolution of the local economy. The whole exerts an influence over partner selection.
Migration and Endogamy According to Social Class: France, 1803–1986
Authors: Pélissier Jean-Pierre , Rébaudo Danielè , van Leeuwen Marco H.D. , Maas Ineke
Published: December 2005

Does intra-national migration matter for partner choice? A number of conflicting hypotheses on the effects of migration on the likelihood of endogamy according to social class of origin are formulated and tested on the French historical record over the past two centuries. We conclude that migrants were less likely to marry endogamously, especially if they migrated from rural villages to cities; this is explained mainly by the fact that they thereby escaped the social pressure of their parents and peers and met more people from different social backgrounds. Contrary to what we expected, the relationships between migration characteristics and endogamy changed hardly at all over the two centuries. We also investigated whether temporal differences in endogamy could be explained partly by changes in migration patterns. We found that they could. The increase in the number of men and women living in or moving to cities was one particularly important cause of the decreasing likelihood of endogamy. Finally, we were interested in the possible bias in regional studies on endogamy. Our results show that this bias is especially large if these regions include only rural areas or cities. This is because the likelihood of endogamy differs between rural areas and cities, and is also especially low for people who move between these two types of region.
“They Live in Indifference Together”: Marriage Mobility in Zeeland, The Netherlands, 1796–1922
Authors: Bras Hilde , Kok Jan
Published: December 2005

This article investigates developments in and antecedents of socially mixed marriage in the rural Dutch province of Zeeland during the long nineteenth century, taking individual and family histories, community contexts, and temporal influences into account. A government report of the 1850s said of Zeeland that farmers and workers lived “in indifference together”. However, our analysis of about 163,000 marriage certificates reveals that 30 to 40 per cent of these rural inhabitants continued to marry outside their original social class. Multivariate logistic regressions show that heterogamous marriages can be explained first and foremost by the life-course experiences of grooms and brides prior to marriage. Previous transitions in their occupational careers (especially to non-rural occupations for grooms, and to service for brides), in their migration trajectories (particularly moves to urban areas), and changes in the sphere of personal relationships (entering widowhood, ageing) are crucial in understanding marriage mobility.
Total and Relative Endogamy by Social Origin: A First International Comparison of Changes in Marriage Choices during the Nineteenth Century
Authors: Maas Ineke , van Leeuwen Marco H.D.
Published: December 2005

The introductory chapter to this volume presented a number of theories and hypotheses on the determinants of endogamy; the following chapters described endogamy in different historical settings and tested some of those hypotheses. The tests looked especially at the effects of individual characteristics of spouses, and sometimes of their parents. Results relating to changes in macro characteristics over time and their effect on the likelihood of endogamy were presented. Because all these chapters refer to only one country or region, regional comparisons are seldom made (there are some exceptions: Bras and Kok on differences between parts of the province of Zeeland; Pélissier et al. on differences between rural and urban areas, and Van de Putte et al. on differences between several Belgian cities and villages).
The contribution of interspecific variation in maximum tree height to tropical and temperate diversity
Authors: King David A. , Wright S. Joseph , Connell Joseph H.
Published: December 2005

Maximum height was assessed for tree species from seven temperate deciduous forests, one subtropical forest and one tropical forest and combined with published tree heights for three other tropical forests. The temperate deciduous forests showed a strong concentration of canopy species and a dearth of subcanopy species. In contrast, the four tropical forests showed more uniform distributions of maximum heights, while the subtropical forest had an intermediate distribution. The tropical and subtropical sites had greater densities of small trees than did the temperate sites and most of these small trees were members of small-to medium-sized species. Sapling recruitment per unit stem basal area increased with declining maximum height in Panama, which is consistent with the criterion for coexistence of species of differing stature derived from Kohyama's forest architecture hypothesis. Greater penetration of light into gaps and favourable conditions for growth over most of the year may allow more smaller-statured species to coexist with canopy trees in tropical vs. temperate forests.
Cognitive Behaviour Therapy for People with Asperger Syndrome
Authors: Anderson Stephen , Morris Jane
Published: December 2005

People with Asperger syndrome (AS) appear to have higher than expected rates of co-morbid psychiatric disorder. The main co-morbid diagnoses are anxiety disorders and depression, but eating disorders, obsessive compulsive disorder, substance abuse and bipolar affective disorder have all been reported. Cognitive Behaviour Therapy (CBT) is used effectively to treat these conditions, so could it be used in people who also have Asperger syndrome? This paper reviews important components and characteristics of cognitive behaviour therapy in relation to its use with people who have Asperger syndrome with reference to the relevant literature and to feedback from people with AS. The use of CBT in people with Asperger syndrome appears promising, but further work is needed to evaluate its effectiveness and to examine which particular aspects of therapy are helpful.
A Longitudinal Investigation of Beliefs about Voices
Authors: Csipke Emese , Kinderman Peter
Published: December 2005

Beliefs about auditory hallucinations have been found to influence voice hearers' behavioural and emotional reactions to the hallucinations. It is currently unknown however, how these beliefs change over time in the absence of psychological intervention or if they remain stable, and how such changes may be related to changes in other symptoms. This study aimed to expand on previous research by exploring the beliefs of voice hearers concerning the malevolence or benevolence of voices in a longitudinal design. Forty-six individuals diagnosed with schizophrenia were assessed with the PANSS, the HAD, and an interview exploring hallucinatory experiences and beliefs about hallucinations over a period of 6 months. General psychopathology and the severity and frequency of hallucinations were found to improve. Voice hearers' beliefs about their voices, however, remained stable. Beliefs do not appear to change without a specific intervention aimed at them and may indeed serve as vulnerability factors. These findings can be interpreted to imply that psychological interventions aimed at modifying such beliefs, such as CBT, might be a necessary component of the treatment of auditory hallucinations.
An efficient approach for the analysis of irregularly contoured planar phased arrays with tapered excitation in complex environments
Authors: Martini E. , Maci S. , Toccafondi A. , Tiberio R.
Published: December 2005

An efficient uniform high‐frequency representation of the radiation from a large irregularly contoured planar tapered phased array, which is accurate throughout the near, intermediate, and far field zones, is presented. The planar array is regarded as the superposition of a sequence of parallel line arrays, and each one of them is represented in terms of equivalent continuous tapered lines via the Poisson summation formula. The amplitude tapering along the line is asymptotically approximated by a physically based, observation‐dependent linear combination of a small number (seven at most) of equiamplitude linearly phased excitations, which allows the reconstruction of the dominant contributions. After superimposing the asymptotic contributions of each line array, the total radiated field from the planar array is described in terms of rays emerging from the actual endpoints on the array rim and from a discrete sequence of points in linear loci on the surface of the array. As a consequence, high‐frequency techniques may effectively be used to describe the interaction of these rays with the surrounding environment.
Tracking changes in bioavailable Fe within high‐nitrate low‐chlorophyll oceanic waters: A first estimate using a heterotrophic bacterial bioreporter
Authors: Mioni Cécile E. , Handy Sara M. , Ellwood Michael J. , Twiss Michael R. , McKay R. Michael L. , Boyd Philip W. , Wilhelm Steven W.
Published: December 2005

It is conventional knowledge that heterotrophic bacteria play a key role in the biogeochemical cycling of oceanic carbon. However, only recently has their role in marine iron (Fe) biogeochemical cycles been examined. Research during this past decade has demonstrated an inextricable link between Fe chemistry and the biota, as >99% of Fe in marine systems is complexed to organic chelates of unknown but obviously biotic origin. Here we present a novel approach to assess and compare Fe bioavailability in low Fe HNLC waters using a bioluminescent bacterial reporter that quantitatively responds to the concentration of bioavailable Fe by producing light. Originally tested in freshwater environments, this study presents the first characterization of this halotolerant reporter organism in a defined seawater medium and then subsequently in marine surface waters. Laboratory characterizations demonstrate that this reporter displays a dose‐dependent response to Fe availability in our defined marine medium. Field tests were performed during the 10‐day mesoscale FeCycle experiment (February 2003) in the Pacific sub‐Antarctic high‐nitrate low‐chlorophyll region. Data from both biogeochemical measures and bioreporter assays are provided which describe how the bioreporter detected changes in Fe bioavailability that occurred during a natural shift in ambient dissolved Fe concentrations (∼40 pM). Our data explore the use of heterotrophic bioluminescent reporters as a comparable tool for marine ecosystems and demonstrate the potential utility of this tool in elucidating the relationship between Fe bioavailability and Fe chemistry in complex marine systems.
Geophysical and hydrological evaluation of two bog complexes in a northern peatland: Implications for the distribution of biogenic gases at the basin scale
Authors: Comas Xavier , Slater Lee , Reeve Andrew
Published: December 2005

Ground penetrating radar (GPR) was used to determine peat basin geometry and the spatial distribution of free‐phase biogenic gasses in two separate units of a northern peatland (Central and Southern Unit of Caribou Bog, Maine). The Central Unit is characterized by a deep basin structure (15 m maximum depth) and a raised (eccentric) bog topographic profile (up to 2 m topographic variation). Here numerous regions of electromagnetic (EM) wave scattering are considered diagnostic of the presence of extensive free‐phase biogenic gas. In contrast, the Southern Unit is shallower (8 m maximum depth) and has a slightly convex upwards bog profile (less than 1 m topographic variation), and areas of EM wave scattering are notably absent. The biogenic gas zones interpreted from GPR in the Central Unit are associated with: (1) wooded heath vegetation at the surface, (2) open pools at the surface, (3) high water table elevations near the center of the basin, and (4) a region of overpressure (at approximately 5 m depth) immediately below the zone of free‐phase gas accumulation. The latter suggests (1) a transient pressure head associated with low hydraulic conductivity resulting from the biogenic gasses themselves or confining layers in the peat that restrict both gas release and groundwater flow and/or (2) overpressure in the peat column as a result of the gas buildup itself. In contrast, the Southern Unit, where zones of EM scattering are absent, is characterized by: (1) predominantly shrub vegetation, (2) a lack of open pools, (3) only minor variations (less than 1 m) in water table elevation throughout the entire unit; and (4) generally upward groundwater flow throughout the basin. The results illustrate the nonuniformity of free‐phase biogenic gas distribution at the peat basin scale and provide insights into the processes and controls associated with CH4 and CO2 accumulation in peatlands.
Spatio‐temporal source characteristics of the 26 December 2004 Sumatra earthquake as imaged by teleseismic broadband arrays
Authors: Krüger F. , Ohrnberger M.
Published: December 2005

We test the capability of broadband arrays at teleseismic distances to image the spatio‐temporal characteristics of the seismic energy release during the Dec 26, 2004 Sumatra earthquake at early observation times. Using a non‐plane‐wave array location technique previously reported values for rupture length (about 1150 km), duration (about 480 s), and average rupture velocity (2.4–2.7 km/s) are confirmed. Three dominant energy releases are identified: one near the hypocenter, a second at 6°N 94°E about 130 s later and a third one after 300 s at 9°N 92–93°E. The spatio‐temporal distribution of the radiated seismic energy in the source region is calculated from the stacked broadband recordings of two arrays in Germany and Japan and results in rough estimates of the total seismic energy of 0.55 · 1018 Nm (GRSN) and 1.53 · 1018 Nm (FNET) respectively. Changes in the relative ratio of energy as function of spatio‐temporal location indicate a rotation of the focal mechanism during the rupture process.
Submarine volcanic activity, ocean‐acoustic waves and internal ocean tides
Authors: Sugioka Hiroko , Fukao Yoshio , Hibiya Toshiyuki
Published: December 2005

Submarine volcanic event often generates acoustic waves (T‐waves) traveling over long distances through the low velocity channel (SOFAR) of the ocean. By a method of coherent stacking of T‐waves from a submarine volcanic activity in northern Mariana, we found a significant semidiurnal variation of T‐wave travel times. The amplitude of variation is an order of larger than those reported in the previous ocean sound transmission experiments. Ray‐theoretical consideration for the numerically simulated ocean tides indicates that such large T‐phase travel time variation is a consequence of large up‐and‐down movement of seawater around the axis of the SOFAR channel due to the M2 internal tide effectively converted from external tidal forcing. T‐phases, a ubiquitous feature of the ocean acoustic noise field, can be used to infer internal tidal motion and the associated ocean mixing.
Electron tomography of nanoparticle clusters: Implications for atmospheric lifetimes and radiative forcing of soot
Authors: van Poppel Laura H. , Friedrich Heiner , Spinsby Jacob , Chung Serena H. , Seinfeld John H. , Buseck Peter R.
Published: December 2005

Nanoparticles are ubiquitous in nature. Their large surface areas and consequent chemical reactivity typically result in their aggregation into clusters. Their chemical and physical properties depend on cluster shapes, which are commonly complex and unknown. This is the first application of electron tomography with a transmission electron microscope to quantitatively determine the three‐dimensional (3D) shapes, volumes, and surface areas of nanoparticle clusters. We use soot (black carbon, BC) nanoparticles as an example because it is a major contributor to environmental degradation and global climate change. To the extent that our samples are representative, we find that quantitative measurements of soot surface areas and volumes derived from electron tomograms differ from geometrically derived values by, respectively, almost one and two orders of magnitude. Global sensitivity studies suggest that the global burden and direct radiative forcing of fractal BC are only about 60% of the value if it is assumed that BC has a spherical shape.
Trends in the draft and extent of seasonal pack ice, Canadian Beaufort Sea
Authors: Melling Humfrey , Riedel David A. , Gedalof Ze'ev
Published: December 2005

Continuous observations by sub‐sea sonar form a 12‐year draft record for seasonal pack ice in the Beaufort Sea. There has been a small trend (0.07 m/decade) to thinner ice, but this has low statistical significance; net change is comparable to the uncertainty of measurement. Although ice concentration at the monitoring site has increased by 0.14 since 1991, there is little evidence for trend in ice‐covered area over the continental shelf in the longer (36‐year) ice‐chart record. However, local air temperature has increased by 1.6 ± 0.6°C during the last three decades. Clearly longer time series are needed to detect and understand change. Changing snow cover, ice circulation and ice deformation may obscure the direct effects of warming climate on seasonal pack ice.
Satellite measurements of daily variations in soil NOx emissions
Authors: Bertram Timothy H. , Heckel Andreas , Richter Andreas , Burrows John P. , Cohen Ronald C.
Published: December 2005

Soil NOx emission from agricultural regions in the western United States has been investigated using satellite observations of NO2 from the SCIAMACHY instrument. We show that the SCIAMACHY observations over a 2 million hectare agricultural region in Montana capture the short intense NOx pulses following fertilizer application and subsequent precipitation and we demonstrate that these variations can be reproduced by tuning the mechanistic parameters in an existing model of soil NOx emissions.
Climatic variability and vegetation vulnerability in Amazônia
Authors: Hutyra L. R. , Munger J. W. , Nobre C. A. , Saleska S. R. , Vieira S. A. , Wofsy S. C.
Published: December 2005

Models of climate change predict close coupling between increases in aridity and conversion of Amazonian forests to savanna. Here we assess the vulnerability and resilience of Amazonian vegetation to climate change by analyzing observed climate‐vegetation relationships using climate data, observed vegetation distributions, and evapotranspiration rates inferred from eddy flux data. We found that drought frequency is an excellent predictor of the forest‐savanna boundary, indicating the key role of extreme climatic events for inducing vegetation change, and highlighting particularly vulnerable regions of Amazônia.
Solar 3He‐rich events and abnormal enhancements of heavy‐ion isotopes accelerated in two stages
Authors: Zhang T. X. , Wang J. X. , Tan A.
Published: December 2005

Heating and acceleration of neon (20Ne), magnesium (24Mg), and their rare isotopes (22Ne and 26Mg) in solar 3He‐rich events are investigated according to the two‐stage acceleration mechanism. It is shown that 20Ne+8, 22Ne+9, 24Mg+10, and 26Mg+11 can be preferentially heated by H‐cyclotron waves with a frequency close to twice the 3He‐cyclotron frequency that also heat 3He, through the third harmonic cyclotron resonance. If the initial electron temperature is in the range of ∼2–10 MK, the abundance ratios 22Ne/20Ne and 26Mg/24Mg in high‐energy particles due to the second‐stage acceleration can be enhanced by a factor of ∼2–6 relative to the solar corona, which are consistent with the measurements of the University of Maryland particle instrument on the Solar Anomalous and Magnetospheric Particle Explorer and the Ultra Lower Energy Isotope Spectrometer particle instrument on the Advanced Composition Explorer.
MF radar observations of meteors and meteor‐derived winds at Syowa (69°S, 39°E), Antarctica: A comparison with simultaneous spaced antenna winds
Authors: Tsutsumi M. , Aso T.
Published: December 2005

The first results of long‐term meteor observations made with Syowa MF radar (69°S, 39°E), Antarctica, are presented. In winter, meteor wind measurements can be conducted throughout the day without being severely affected by group retardation or total reflection, while in summer the observations are confined within several hours around 0000 local time (LT). Daily meteor echo rates (roughly 300–1000) are clearly anticorrelated with local K indices, indicating that the observations mostly represent geomagnetically quiet conditions. Echoes are distributed from around 80 km to 120 km, with the peak altitude at around 100 km. The maximum height is set by the relatively slow sampling frequency employed (5 Hz) and is expected to be extended by using a higher frequency. Meteor and full correlation analysis (FCA) winds in winter months are compared. They agree well at around 90 km, while the FCA winds tend to underestimate the meteor winds at upper altitudes. A notable finding is that the directions of wind velocities can also be different. The FCA winds show less height variations above about 90 km and it appears as though the FCA heights are overestimated. A case study of angles of arrival estimated from MF echoes suggests a possibility that meteor echoes contaminate ionospheric echoes down to as low as 80 km. However, quantitative evaluation of meteor contamination effects, if any, on FCA wind velocities has not been done yet and remains a future topic to be studied. Other sources which cause the differences should also be sought. The remarkably wide height coverage of the present MF radar observations (from around 60 to nearly 120 km) using both FCA and meteor techniques simultaneously will greatly contribute to polar mesosphere and lower thermosphere study.
Net radiative forcing due to changes in regional emissions of tropospheric ozone precursors
Authors: Naik Vaishali , Mauzerall Denise , Horowitz Larry , Schwarzkopf M. Daniel , Ramaswamy V. , Oppenheimer Michael
Published: December 2005

The global distribution of tropospheric ozone (O3) depends on the emission of precursors, chemistry, and transport. For small perturbations to emissions, the global radiative forcing resulting from changes in O3 can be expressed as a sum of forcings from emission changes in different regions. Tropospheric O3 is considered in present climate policies only through the inclusion of indirect effect of CH4 on radiative forcing through its impact on O3 concentrations. The short‐lived O3 precursors (NOx, CO, and NMHCs) are not directly included in the Kyoto Protocol or any similar climate mitigation agreement. In this study, we quantify the global radiative forcing resulting from a marginal reduction (10%) in anthropogenic emissions of NOx alone from nine geographic regions and a combined marginal reduction in NOx, CO, and NMHCs emissions from three regions. We simulate, using the global chemistry transport model MOZART‐2, the change in the distribution of global O3 resulting from these emission reductions. In addition to the short‐term reduction in O3, these emission reductions also increase CH4 concentrations (by decreasing OH); this increase in CH4 in turn counteracts part of the initial reduction in O3 concentrations. We calculate the global radiative forcing resulting from the regional emission reductions, accounting for changes in both O3 and CH4. Our results show that changes in O3 production and resulting distribution depend strongly on the geographical location of the reduction in precursor emissions. We find that the global O3 distribution and radiative forcing are most sensitive to changes in precursor emissions from tropical regions and least sensitive to changes from midlatitude and high‐latitude regions. Changes in CH4 and O3 concentrations resulting from NOx emission reductions alone produce offsetting changes in radiative forcing, leaving a small positive residual forcing (warming) for all regions. In contrast, for combined reductions of anthropogenic emissions of NOx, CO, and NMHCs, changes in O3 and CH4 concentrations result in a net negative radiative forcing (cooling). Thus we conclude that simultaneous reductions of CO, NMHCs, and NOx lead to a net reduction in radiative forcing due to resulting changes in tropospheric O3 and CH4 while reductions in NOx emissions alone do not.
An examination of the differences between surface and free‐air temperature trend at high‐elevation sites: Relationships with cloud cover, snow cover, and wind
Authors: Pepin N. C. , Norris J. R.
Published: December 2005

Contrasts in high‐elevation surface and free‐tropospheric temperatures between 1971 and 1996 are examined by comparing surface temperatures from a subset of 72 stations in the GHCN (Global Historical Climate Network) and CRU (Climatic Research Unit) homogeneity adjusted surface data sets with free‐air temperatures interpolated to the same locations from NCEP/NCAR Reanalysis R1. The selected stations are above the mean elevation of the surrounding topography, often located on mountain summits. Surface temperatures, free‐air temperatures, and their difference (ΔT) are found to be related to independent surface cloud observations from the NDP‐026C archive, local wind speed, satellite records of snow cover (NSIDC), and reanalysis wind components. Significant correlations are observed at most stations, and correlation spatial patterns are consistent for different subperiods of the record (e.g., presatellite era versus satellite era). Stepwise regression models built to predict surface temperatures, free‐air temperatures, and ΔT from the above meteorological parameters typically explain 20–40% of the temperature variability on an annual basis and more for individual seasons. The stationarity of relationships between temperature and snow/cloud/wind is examined by comparing the temporal trends in the original temperatures with predicted trends from the best fit regression model and trends in model residuals. This provides an assessment of how much of any ΔT trends can be accounted for by changes in meteorology. Significant daytime ΔT residual trends occur primarily in Turkey and eastern China, but significant nighttime ΔT residual trends are more geographically widespread. While daytime residual trends may be the result of surface radiative cooling by increasing anthropogenic aerosol, attribution of nighttime residual trends is uncertain.
Regional climate model simulation of U.S. soil temperature and moisture during 1982–2002
Authors: Zhu Jinhong , Liang Xin‐Zhong
Published: December 2005

The fifth‐generation PSU‐NCAR Mesoscale Model (MM5)‐based regional climate model (CMM5) capability in simulating the U.S. soil temperature and soil moisture annual cycle and interannual variability is evaluated by comparing the 1982–2002 continuous integration driven by the NCEP‐DOE AMIP II reanalysis (R‐2) with observations, the R‐2 derivatives and North American Land Data Assimilation System (NLDAS) products. For the annual cycle, the CMM5 produces more realistic regional details and overall smaller biases than the driving R‐2 and NLDAS outputs. The CMM5 also faithfully simulates interannual variations of soil temperature over the central United States and soil moisture in Illinois and Iowa, where observational data are available. The existing CMM5 differences from observations in soil temperature (moisture) cannot be fully explained by model biases in surface air temperature (precipitation). Inconsistencies between measurements taken under short grass versus model representations beneath other land cover types may play an important role. In particular, such measurements overestimate soil temperature in summer and fall while generating a 1‐month phase lead in the soil moisture annual cycle with respect to croplands in the model. The result emphasizes the need for more comprehensive study on model evaluation and bias understanding of soil temperature and soil moisture.
Styles and timing of volatile‐driven activity in the eastern Hellas region of Mars
Authors: Crown David A. , Bleamaster Leslie F. , Mest Scott C.
Published: December 2005

Recent analyses of Mars Global Surveyor and Mars Odyssey data sets provide new insights into the geologic evolution of the eastern Hellas region of Mars, in particular, the role of volatiles. Here, we present results of our recent work and integrate these with previous studies by various investigators to provide a synthesis of the history of volatile‐driven activity of the region. We utilize high‐resolution images from the Mars Orbiter Camera and Thermal Emission Imaging System combined with Mars Orbiter Laser Altimeter digital elevation models and profiles to examine fluvial systems that dissect the circum‐Hellas highlands, to characterize stages in the development of the Dao, Niger, Harmakhis, and Reull Valles canyon systems, and to evaluate evidence for ancient lakes in Hellas Planitia. The occurrence of valley networks, dissected highland crater rims, and crater interior deposits such as layered plateaus suggests widespread ancient degradation of the circum‐Hellas highlands. Canyon development, which represents subsequent more localized activity, may have included an early fluvial phase followed by the collapse and sapping dominated stages that, along with recent wall erosion and floor resurfacing, produced the currently observed morphologies. The prominent role of collapse and sapping along the east rim of Hellas, along with the presence of numerous channels extending toward the basin and sequences of finely layered deposits along the basin rim, suggests a volatile‐rich substrate across a broad depositional shelf. The east rim of the basin was an accumulation zone for atmospheric volatiles and/or the edge of volatile‐rich deposits associated with the basin floor. This evidence combined with topographic data and cratered terrain preservation around the basin is consistent with a lacustrine period or periods in early Martian history. The style, magnitude, and spatial extent of volatile‐driven activity in eastern Hellas have varied considerably with time, and these variations may represent a transition from a water‐ to an ice‐dominated surface environment.
Empirical models of the low‐energy plasma in the inner magnetosphere
Authors: Roeder J. L. , Chen M. W. , Fennell J. F. , Friedel R.
Published: December 2005

Particle flux measurements by the Charge and Mass Magnetospheric Ion Composition Experiment/Magnetospheric Ion Composition Spectrometer (CAMMICE/MICS) and Hydra instruments on the NASA Polar satellite have been used to build empirical models of the plasma environment at low energies in the Earth's inner magnetosphere. These models may be used to develop design and to test specifications for spacecraft surface materials, which are susceptible to damage by the ions. The combination of the CAMMICE/MICS and Hydra models provides the ion flux at energies in the range 20 eV to 200 keV as a function of position in the magnetosphere. For the 1–200 keV energy range, the H+ and O+ ion flux is estimated separately using the CAMMICE/MICS data. Average environments have been calculated for several sample orbital trajectories: a geosynchronous orbit and the orbits of several satellites in the Global Positioning System (GPS) constellation. At high energies (∼100 keV), the flux estimates agree with corresponding estimates from the NASA AP‐8 model, but the fluxes at low energies are larger than those extrapolated simply from AP‐8. The CAMMICE/MICS model shows that H+ dominates the >2 keV ion populations, but the O+ flux becomes comparable to the H+ flux at ∼1 keV. The standard deviation of both the ion and electron flux was found to be 100–200% of the average value over the entire considered energy range. The average 1–200 keV O+ flux estimates for GEO appear similar to the averages for GPS orbit, so material damage due to O+ in this energy range should be similar for the two orbits.
Incipient sediment motion at high slopes in uniform flow condition
Authors: Armanini Aronne , Gregoretti Carlo
Published: December 2005

This paper reviews the problem of the incipient motion of cohesionless particles in a high sloping water stream. A theoretical analysis of the equilibrium of a gravel particle is developed by a deterministic approach with the introduction of the relative degree of exposure of the particle itself to the stream flow. The parameter, relative degree of exposure, relates the positioning of a particle with the upstream one. The problem of velocity distribution and the definition of drag coefficient is also revised to better account for low submergence. The results of the theory are compared with a series of ad hoc experiments performed by C. Gregoretti.
Flood damage and influencing factors: New insights from the August 2002 flood in Germany
Authors: Thieken Annegret H. , Müller Meike , Kreibich Heidi , Merz Bruno
Published: December 2005

In the aftermath of a severe flood event in August 2002 in Germany, 1697 computer‐aided telephone interviews were undertaken in flood‐affected private households. Besides the damage to buildings and contents a variety of factors that might influence flood damage were queried. It is analyzed here how variables describing flood impact, precaution, and preparedness as well as characteristics of the affected buildings and households vary between the lower and upper damage quartiles of all affected households. The analysis is supplemented by principal component analyses. The investigation reveals that flood impact variables, particularly water level, flood duration, and contamination are the most influential factors for building and for content damage. This group of variables is followed by items quantifying the size and the value of the affected building/flat. In comparison to these factors, temporal and permanent resistance influences damage only to a small fraction, although in individual cases, precaution can significantly reduce flood damage.