bluuebunny/crossref_metadata_2025 huggingface dataset:
Mining temporal rules for software maintenance
Authors: Lo David , Khoo Siau‐Cheng , Liu Chao
Published: July 2008

Software evolution incurs difficulties in program comprehension and software verification, and hence it increases the cost of software maintenance. In this study, we propose a novel technique to mine from program execution traces a sound and complete set of statistically significant temporal rules of arbitrary lengths. The extracted temporal rules reveal invariants that the program observes, and will consequently guide developers to understand the program behaviors, and facilitate all downstream applications such as verification and debugging. Different from previous studies that were restricted to mining two‐event rules (e.g., 〈lock〉→〈unlock〉), our algorithm discovers rules of arbitrary lengths. In order to facilitate downstream applications, we represent the mined rules as temporal logic expressions, so that existing model checkers or other formal analysis toolkit can readily consume our mining results. Performance studies on benchmark data sets and a case study on an industrial system have been performed to show the scalability and utility of our approach. We performed case studies on JBoss application server and a buggy concurrent versions system application, and the result clearly demonstrates the usefulness of our technique in recovering underlying program designs and detecting bugs. Copyright © 2008 John Wiley & Sons, Ltd.
Random variate generator
Authors: Laracy Joseph R.
Published: July 2008

As the use of computer simulation grows in a variety of science and engineering fields, the quality of random variate generators becomes increasingly important. Unfortunately, a number of standard implementations are grossly inadequate and exhibit poor statistical properties. This paper presents a software pattern for efficiently implementing an extensible, high‐quality random variate generator. Copyright © 2008 John Wiley & Sons, Ltd.
Automotive–adept: A lightweight assessment method for the automotive software industry
Authors: Mc Caffery Fergal , Richardson Ita , Moller Peter a
Published: July 2008

In this article we describe how a lightweight assessment method was developed to educate Irish software small‐ to medium‐sized enterprises (SMEs)1in relation to becoming automotive software suppliers. The main goal of this assessment method is to provide software SMEs with a software process improvement (SPI) path to becoming automotive software suppliers. Copyright © 2008 John Wiley & Sons, Ltd.
Effect of roasting time and storage time on sensory attributes and consumer acceptability of peanut butters in southern Africa
Authors: Tomlins Keith , Rukuni Tunga , Mutungamiri Angeline , Mandeya Sheila , Swetman Anthony
Published: July 2008

This study explored how sensory attributes and consumer acceptability of peanut butters varied with differing roasting times (40 to 55 min) and storage times (up to 48 weeks) for shelf‐life testing. Quantitative descriptive analysis generated sensory terms that were appropriate to the local situation. Increased roasting time was associated with the sensory attributes brown colour, roasted taste and burnt taste. Consumer acceptance varied among consumers with two preferred roasting times of either 40 min (67% of consumers) or 50 min (23% of consumers). This was related to distinct peanut flavour profiles. During the storage study of five selected butters consumer acceptability did not alter with storage period. Sensory testing, however, was more sensitive to product changes: sensory attributes that varied with storage were sticky texture, stale odour and sweetness. Copyright © 2008 John Wiley & Sons, Ltd
Array‐based reader anti‐collision scheme for highly efficient RFID network applications
Authors: Chen Nong‐Kun , Chen Jiann‐Liang , Lee Cheng‐Chun
Published: July 2008

Radio frequency identification (RFID) is a technology for identifying objects by radio signal. The reader collision problem is caused by the interrogation zones overlap of multiple readers, and leading to incorrect and unreliable data. This study proposes an array‐based reader anti‐collision scheme (ARCS) for solving the reader‐to‐tag interference problem. This mechanism uses array and grouping techniques to schedule the active readers to reduce the read cycle (RC) time. The ‘RC’ and ‘collision ratio (CR)’ measures serve as performance indexes in the proposed scheme. From ‘RC’ comparison, the ARCS mechanism has the maximum improvement of 55 per cent as compared with the existing mechanisms. Furthermore, take ‘CR’ index, ARCS has the maximum improvement of 42 per cent as compared to the others. Copyright © 2008 John Wiley & Sons, Ltd.
Controlled flooding in disconnected sparse mobile networks
Authors: Harras Khaled A. , Almeroth Kevin C.
Published: July 2008

The incredible growth in the capabilities and functionality of mobile devices has enabled new applications and network architectures to emerge. Due to the potential for node mobility, along with significant node heterogeneity, characteristics such as very large delays, intermittent links, and high link error rates pose a new set of network challenges. Along with these challenges, end‐to‐end paths are assumed not to exist and message relay approaches are often adopted. While message flooding is a simple and robust solution for such cases, its cost in terms of network resource consumption is unaffordable. In this paper, we focus on the evaluation of different controlled message flooding schemes over disconnected sparse mobile networks. We study the effect of these schemes on message delay, network resource consumption, and neighbor discovery overhead. Our simulations show that our schemes can save substantial network resources while incurring a negligible increase in the message delivery delay. Copyright © 2008 John Wiley & Sons, Ltd.
Dominant marker vectors for selecting yeast mating products
Authors: Sadowski Ivan , Lourenco Pedro , Parent Jennifer
Published: July 2008

We have developed plasmid vectors to enable selection of diploids from mating reactions between haploid strains that lack compatible recessive genetic markers. The plasmids bear one of five different dominant selectable markers, kanMX4, hphMX4, natMX4, patMX3 or ZEO, a yeast origin of replication, and the URA3 gene. Diploids can be selected from mating reactions between haploids transformed with plasmids expressing different dominant markers, by using a combination of drugs that select for both markers. Following non‐selective growth, diploids that subsequently become cured of the plasmids can be directly selected on 5‐FOA, for ura3 auxotrophs, or identified by replica‐plating onto appropriate selective media. Copyright © 2008 John Wiley & Sons, Ltd.
Low‐copy episomal vector pFY20 and high‐saturation coverage genomic libraries for the fission yeast Schizosaccharomyces pombe
Authors: Wahls Wayne P. , Davidson Mari K.
Published: July 2008

In fission yeast, as in many organisms, episomally replicating plasmid DNA molecules can be used for a wide variety of applications. However, replicating plasmids described previously are each propagated at a high copy number per cell. Plasmid fission yeast twenty (pFY20) contains the ura4+ gene for positive and negative selection, an origin of replication (ars1) and a stability element (stb). Although this plasmid does not have a centromere, it is propagated with a copy number of about two plasmids per haploid genome equivalent and it is transmitted with relatively high fidelity in mitosis and meiosis. This low‐copy vector is useful for screens and mutational studies where overexpression (e.g. from high copy plasmids) is undesirable. We therefore constructed multiple partial‐digest, size‐fractionated, fission yeast genomic DNA libraries in pFY20 and in the cloning vector pBluescript KS+. These libraries have sufficient complexity (average of 2100 genome equivalents each) for saturation screening by complementation, plasmid shuffle or hybridization. Copyright © 2008 John Wiley & Sons, Ltd.
A survey of the management and development of captive African elephant (Loxodonta africana) calves: birth to three months of age
Authors: Kowalski Nicole L. , Dale Robert H. I. , Mazur Christa L. H.
Published: July 2008

We used four surveys to collect information about the birth, physical growth, and behavioral development of 12 African elephant calves born in captivity. The management of the birth process and neonatal care involved a variety of standard procedures. All of the calves were born at night, between 7PM and 7AM. The calves showed a systematic progression in behavioral and physical development, attaining developmental milestones at least a quickly as calves in situ. This study emphasized birth‐related events, changes in the ways that calves used their trunks, first instances of behaviors, and interactions of the calves with other, usually adult, elephants. Several behaviors, such as the dam covering her calf with hay and the calf sucking its own trunk, were common in the captive situation and have been observed in situ. Overall, the behaviors of the calves resembled those observed for African elephant calves in situ. These data should help in the management of African elephants under human care by providing systematic reference values for the birth and development of elephant calves. Zoo Biol 29:104–119, 2010. © 2008 Wiley‐Liss, Inc.
Pregnancy diagnosis in wild canids using a commercially available relaxin assay
Authors: Bauman Joan E. , Clifford Deana L. , Asa Cheryl S.
Published: July 2008

Accurate detection of pregnancy is a useful tool in zoo management and husbandry, conservation breeding programs and research settings. Our study evaluated the ability of a commercial relaxin hormone assay used in domestic dogs (ReproCHEKTM) to accurately detect pregnancy through plasma analysis in two wolf and two fox species. The relaxin assay detected all of the pregnancies greater than 25 days gestation for island foxes, fennec foxes, gray wolves, and Mexican gray wolves. For island foxes, three negative relaxin results were attributed to using the test earlier postconception than manufacturer recommendation (before day 20). Five other negative results were found for females estimated at 15–25 days gestation, spanning the early and intermediate period (21–30 days gestation) when relaxin may be detected but less reliably. There were no false‐positive results in nonmated negative control animals. Relaxin assay results were highly correlated with ultrasound results and the intra‐assay replicate agreement was 100%. Our results show that the ReproCHEKTM commercial relaxin assay is a minimally invasive and reliable method for pregnancy detection in these wild species when used after 25 days gestation and might be applied to other canids as well. Furthermore, this assay is easy to run and requires no specialized equipment, making it extremely useful for zoo and field research applications. Zoo Biol 27:406–413, 2008. © 2008 Wiley‐Liss, Inc.
Phenology of body mass changes during reproduction in a nomadic, tropical waterbird, the Scarlet Ibis (Eudocimus ruber)
Authors: Babbitt Gregory A. , Frederick Peter C.
Published: July 2008

In birds, the prereproductive buildup of endogenous energy reserves (e.g. body fat) is highly variable and is often thought to be a strategy evolving in response to either seasonal and/or unpredictable changes in breeding conditions. Nomadic behavior is also thought to be an adaptation to unpredictable resource distribution in both space and time. Because of the difficultly in obtaining a longitudinal time series of body masses for free‐living individuals of highly nomadic species, the relationship between nomadism and endogenous energy storage has not been explored. In this study, we investigated prereproductive energy storage in a large free‐flighted captive colony of highly nomadic waterbird, the Scarlet Ibis, Eudocimus ruber. We used size‐corrected body mass as an index of body condition both earlier to and during breeding. We compared both breeders and nonbreeders body condition earlier to nesting. We also prevented a subsample of the birds from gaining mass earlier to nesting and compared their nesting success with a control group that was allowed to feed freely. Although significant differences were found in prereproductive body conditions of breeders and nonbreeders, we were unable to control breeding by manipulating prereproductive condition, most likely because of the ability of some birds to rapidly change body condition within several days or weeks earlier to nesting. We conclude that prereproductive energy storage is important for nesting success in both sexes of this highly nomadic species, however energy stores are highly labile and can be rapidly obtained through prenesting hyperphagia. Zoo Biol 27:360–370, 2008. © 2008 Wiley‐Liss, Inc.
Neurocognitive testing in late‐onset Tay–Sachs disease: A pilot study
Authors: Elstein D. , Doniger G. M. , Simon E. , Korn‐Lubetzki I. , Navon R. , Zimran A.
Published: July 2008

Objectives

To test neurocognitive function in patients with late‐onset Tay–Sachs disease (LOTS) using a computerized system to assess whether cognition is a clinically relevant outcome measure of possible therapeutic intervention in LOTS.

Methods

Ten adults with Tay–Sachs disease were administered at least one battery of the Mindstreams Neurotrax system for evaluation of cognitive function. Six sub‐scores and a Global Cognitive Score (GCS) were tabulated. A disease specific severity score was also devised with six domains.

Results

Despite identical genotypes, all patients but the two oldest had ≥3/6 sub‐scores one standard deviation below normal mean (100); verbal and executive functions were most affected. The severity score measured other functions.

Conclusions

Because of provocative findings on re‐testing in patients exposed to miglustat, and despite the very small cohort, cognitive function may be an appropriate and clinically relevant outcome measure for future therapeutic interventions in LOTS.
Physico‐Chemical Characterisation of Lipids from Mytilus galloprovincialis (L.) and Rapana venosa and their Healing Properties on Skin Burns
Authors: Badiu Diana L. , Balu Alina M. , Barbes Lucica , Luque Rafael , Nita Roxana , Radu Marius , Tanase Ecaterina , Rosoiu Natalia
Published: July 2008

Black Sea molluscs and gastropods are the most studied organisms from the Romanian littoral zone. In particular, those from the Mytilidae species are of great interest because biochemical investigations have shown that they can be sources of biological active substances which can have different applications (e.g. food additives). We report here the extraction of lipids from two different species of molluscs (Mytilus galloprovincialis L., Mediterranean mussel) and gastropods (Rapana venosa, hard‐shell clam). The extracts were evaluated in terms of antioxidant and composition properties and their healing properties were tested on skin burns in Wistar rats. Our studies proved that the two lipid extracts contained a relatively complex distribution of compounds, in terms of characteristic indices, polyunsaturated fatty acids (PUFA) and vitamins E and D. The presence of such compounds rendered the extracts very efficient in healing induced skin burns in Wistar rats. The histological analysis showed a reduction in the time of healing (12–13 and 13–15 days for the Mytilus galloprovincialis (L.) Rapana venosa extracts, respectively) compared to 20–22 for untreated animals, based on results from tissues and blood samples. Our investigations have been proved to be promising in terms of future potential applications of the extracts as skin‐care products, cosmetics and/or pharmaceutical preparations owing to their dermorestitutive properties.
On reduction maps for the étale and Quillen K-theory of curves and applications
Authors: Barańczuk Stefan , Górnisiewicz Krzysztof
Published: July 2008

In this paper we consider reduction of nontorsion elements in the étale and Quillen K-theory of a curve X over a number field. As an application we solve two problems: detecting linear dependence and the support problem.
Differential evolution tuned fuzzy supervisor adapted extended Kalman filtering for SLAM problems in mobile robots
Authors: Chatterjee Amitava
Published: July 2008

The present paper proposes a successful application of differential evolution (DE) optimized fuzzy logic supervisors (FLS) to improve the quality of solutions that extended Kalman filters (EKFs) can offer to solve simultaneous localization and mapping (SLAM) problems for mobile robots and autonomous vehicles. The utility of the proposed system can be readily appreciated in those situations where an incorrect knowledge of Q and R matrices of EKF can significantly degrade the SLAM performance. A fuzzy supervisor has been implemented to adapt the R matrix of the EKF online, in order to improve its performance. The free parameters of the fuzzy supervisor are suitably optimized by employing the DE algorithm, a comparatively recent method, popularly employed now-a-days for high-dimensional parallel direct search problems. The utility of the proposed system is aptly demonstrated by solving the SLAM problem for a mobile robot with several landmarks and with wrong knowledge of sensor statistics. The system could successfully demonstrate enhanced performance in comparison with usual EKF-based solutions for identical environment situations.
GENERALIZED AUTOREGRESSIVE CONDITIONAL CORRELATION
Authors: McAleer Michael , Chan Felix , Hoti Suhejla , Lieberman Offer
Published: July 2008

This paper develops a generalized autoregressive conditional correlation (GARCC) model when the standardized residuals follow a random coefficient vector autoregressive process. As a multivariate generalization of the Tsay (1987, Journal of the American Statistical Association 82, 590–604) random coefficient autoregressive (RCA) model, the GARCC model provides a motivation for the conditional correlations to be time varying. GARCC is also more general than the Engle (2002, Journal of Business & Economic Statistics 20, 339–350) dynamic conditional correlation (DCC) and the Tse and Tsui (2002, Journal of Business & Economic Statistics 20, 351–362) varying conditional correlation (VCC) models and does not impose unduly restrictive conditions on the parameters of the DCC model. The structural properties of the GARCC model, specifically, the analytical forms of the regularity conditions, are derived, and the asymptotic theory is established. The Baba, Engle, Kraft, and Kroner (BEKK) model of Engle and Kroner (1995, Econometric Theory 11, 122–150) is demonstrated to be a special case of a multivariate RCA process. A likelihood ratio test is proposed for several special cases of GARCC. The empirical usefulness of GARCC and the practicality of the likelihood ratio test are demonstrated for the daily returns of the Standard and Poor's 500, Nikkei, and Hang Seng indexes.
ASYMPTOTIC PROPERTIES OF NONPARAMETRIC FRONTIER ESTIMATORS
Authors: Horváth Lajos , Horváth Zsuzsanna , Zhou Wang
Published: July 2008

Aragon, Daouia, and Thomas-Agnan (2005, Econometric Theory 21, 358–389) introduced a new nonparametric frontier estimation. We prove the weak convergence of the empirical conditional quantile function. The distribution of the limit depends on the unknown conditional quantile density function. We provide a method to construct uniform confidence bands without estimating the conditional quantile density.
NOTES AND PROBLEMS A GENERAL BOUND FOR THE LIMITING DISTRIBUTION OF BREITUNG'S STATISTIC
Authors: Davidson James , Magnus Jan R. , Wiegerinck Jan
Published: July 2008

We consider the Breitung (2002, Journal of Econometrics 108, 343–363) statistic ξn, which provides a nonparametric test of the I(1) hypothesis. If ξ denotes the limit in distribution of ξn as n → ∞, we prove (Theorem 1) that 0 ≤ ξ ≤ 1/π2, a result that holds under any assumption on the underlying random variables. The result is a special case of a more general result (Theorem 3), which we prove using the so-called cotangent method associated with Cauchy's residue theorem.
REDUNDANCY OF MOMENT CONDITIONS AND THE EFFICIENCY OF OLS IN SUR MODELS
Authors: Qian Hailong
Published: July 2008

In this note, based on the generalized method of moments (GMM) interpretation of the usual ordinary least squares (OLS) and feasible generalized least squares (FGLS) estimators of seemingly unrelated regressions (SUR) models, we show that the OLS estimator is asymptotically as efficient as the FGLS estimator if and only if the cross-equation orthogonality condition is redundant given the within-equation orthogonality condition. Using the condition for redundancy of moment conditions of Breusch, Qian, Schmidt, and Wyhowski (1999, Journal of Econometrics 99, 89–111), we then derive the necessary and sufficient condition for the equal asymptotic efficiency of the OLS and FGLS estimators of SUR models. We also provide several useful sufficient conditions for the equal asymptotic efficiency of OLS and FGLS estimators that can be interpreted as various mixings of the two famous sufficient conditions of Zellner (1962, Journal of the American Statistical Association 57, 348–368).
THE A.R. BERGSTROM PRIZE IN ECONOMETRICS: 2007
Authors: Hall V.B. , Phillips P.C.B.
Published: July 2008

We are pleased to announce award of the A.R. Bergstrom Prize in Econometrics for 2007 to Melanie Morten, Ph.D. student, Yale University, for her paper, “Healthy and Wealthy? Examining the Causality between Income and Life Expectancy.”
Surface exposure ages imply multiple low-amplitude Pleistocene variations in East Antarctic Ice Sheet, Ricker Hills, Victoria Land
Authors: Strasky Stefan , Di Nicola Luigia , Baroni Carlo , Salvatore Maria Cristina , Baur Heinrich , Kubik Peter W. , Schlüchter Christian , Wieler Rainer
Published: July 2008

One of the major issues in (palaeo-) climatology is the response of Antarctic ice sheets to global climate changes. Antarctic ice volume has varied in the past but the extent and timing of these fluctuations are not well known. In this study, we address the question of amplitude and timing of past Antarctic ice level changes by surface exposure dating using in situ produced cosmogenic nuclides (10Be and 21Ne). The study area lies in the Ricker Hills, a nunatak at the boundary of the East Antarctic Ice Sheet in southern Victoria Land. By determining exposure ages of erratic boulders from glacial drifts we directly date East Antarctic Ice Sheet variations. Erosion-corrected neon and beryllium exposure ages indicate that a major ice advance reaching elevations of about 500 m above present ice levels occurred between 1.125 and 1.375 million years before present. Subsequent ice fluctuations were of lesser extent but timing is difficult as all erratic boulders from related deposits show complex exposure histories. Sample-specific erosion rates were on the order of 20–45 cm Ma-1 for a quartzite and 10–65 cm Ma-1 for a sandstone boulder and imply that the modern cold, arid climate has persisted since at least the early Pleistocene.
Detecting Comorbid Axis-II Status Among Inpatients Using the MMPI-2 Restructured Clinical Scales
Authors: Kamphuis Jan H. , Arbisi Paul A. , Ben-Porath Yossef S. , McNulty John L.
Published: July 2008

This study examined the differential diagnostic utility of the MMPI-2 Restructured Clinical Scales (RCS) and Clinical Scales (CS) in detecting a complex multivariate clinical phenomenon: that is, comorbid Axis-II status in two matched samples of inpatients. Psychiatric inpatients diagnosed with either substance use disorder (n = 43) or major depression (n = 49) were matched on age, sex, and clinical setting, and compared with patients with the same Axis-I disorder and a comorbid personality disorder. Presence or absence of a comorbid personality disorder was chosen to provide a potent test of the differential diagnostic utility of the RCS versus CS when using a highly complex, multivariate criterion variable. Using hierarchical logistic regression analyses, the RCS consistently demonstrated higher diagnostic utility. Moreover, the RCS profiles were significantly more focused and more readily interpretable, relative to the CS profiles that were remarkably similar across disorders. These findings provide further support for the diagnostic and clinical utility of the RCS.
Measuring Self-Serving Cognitive Distortions with the “How I Think” Questionnaire
Authors: Nas Coralijn N. , Brugman Daniel , Koops Willem
Published: July 2008

The aim of this study was to investigate the reliability and validity of the How I Think Questionnaire (HIT-Q), a paper-and-pencil instrument that measures self-serving, cognitive distortions. Our main hypothesis was that delinquent adolescents incarcerated in high-security juvenile correctional facilities in the Netherlands would show a higher level of cognitive distortion than their nondelinquent peers. A total of 311 delinquent and 142 nondelinquent male adolescents participated in the study. The Dutch version of the HIT-Q showed acceptable reliability and validity. Delinquent adolescents exhibited more cognitive distortions than nondelinquent adolescents. However, in contrast to the original North American version of the HIT-Q, the relationship with moral judgment was inconclusive and a correlation with intelligence was found. Both delinquent and nondelinquent young people with lower levels of education scored in the borderline-clinical range on several types of cognitive distortions. These results seem to imply that cognitive distortions are much more prevalent in nondelinquent pupils with lower levels of education than expected. Further research into cognitive distortions in nondelinquent adolescents is proposed.
A mid‐Pleistocene deformation transition in the Hula basin, northern Israel: Implications for the tectonic evolution of the Dead Sea Fault
Authors: Schattner U. , Weinberger R.
Published: July 2008

The Dead Sea fault (DSF) plate boundary has accommodated relative sinistral motion between the Sinai and Arabian plates since the Neogene. Geologically based models point to a long‐term (5–0 ma) ∼N‐trending relative motion roughly parallel to the central sector of the DSF. GPS‐based calculations of present‐day relative motion between the Sinai and Arabian plates indicate a northward increasing convergent component across the DSF, suggesting a kinematic change over the Plio‐Pleistocene period. We study the evolving deformation of the Hula rhomb‐shaped graben situated along the central sector of the DSF in order to examine the possible kinematic change. The Hula graben is widely accepted as a pull‐apart basin, part of a series of basins extending southward. We use a 3‐D approach, combining mapped surface structures with subsurface seismic reflection profiles (∼173 km) and borehole data (38 boreholes), gathered here into a single geographic information systems database. Results indicate that during the mid‐Pleistocene a major tectonic transition modified the structure of the basin fill. A subvertical NNW‐trending left‐lateral throughgoing strike‐slip fault developed diagonally across the basin. Consequently, the basin entered a new geodynamic phase where subsidence was controlled by both the basin bordering faults and the diagonal fault, while the vertical displacement across the transverse faults is minor. Synchronous structural changes recorded in additional localities along the DSF attests to a mid‐Pleistocene (∼1 ma) regional tectonic transition that was associated with a northward increasing convergent component across the central and northern sectors of the DSF.
Equivalent ionospheric currents for the 5 December 2006 solar flare effect determined from spherical cap harmonic analysis
Authors: Gaya‐Piqué L. R. , Curto J. J. , Torta J. M. , Chulliat Arnaud
Published: July 2008

In this paper we analyze the prompt solar flare effect (SFE) associated to a strong X‐ray flare that occurred on 5 December 2006 by using spherical cap harmonic analysis applied to the variations recorded in the European magnetic observatories network. The regional model allows the simultaneous modeling in space and time of the ionospheric equivalent current system responsible for the SFE, as well as for the regular diurnal variation SR on that day. It is found that the SFE equivalent current system does not form as an enhancement of the SR system. Its focus is distinct from that of the SR, and it is located between 3 and 10° higher in latitude and circa 40 min later in local time.
A slow mode transition region adjoining the front boundary of a magnetic cloud as a relic of a convected solar wind feature: Observations and MHD simulation
Authors: Farrugia Charles J. , Erkaev Nikolai V. , Taubenschuss Ulrich , Shaidurov Vladimir A. , Smith Charles W. , Biernat Helfried K.
Published: July 2008

We identify a planar, pressure‐balanced structure bounded by sharp changes in the dynamic pressure plastered against the front boundary of the magnetic cloud which passed Earth on 20 November 2003. The front boundary of the magnetic cloud (MC) is particularly well‐defined in this case, being located where the He++/H+ number density ratio jumps from 4 to 10% for the first time and the proton plasma beta decreases sharply from ∼1 to ∼0.001. The feature, estimated to have a length scale ∼50 RE in the Sun‐Earth direction, bears close resemblance to a slow mode transition region in that the magnetic pressure decreases, the plasma pressure increases, and their temporal variations are anticorrelated. Using a 2‐D MHD simulation, we hypothesize that a pressure‐balanced structure was encountered by the MC en route to Earth. Our calculations reproduce qualitatively the major features of the observations. Using a simplified geometry suggested by the observations, we find that the lateral deflection speed of the plasma is less than the lateral expansion speed of the MC. We infer that the structure traversed the MC sheath in ∼20 h, consistent with its crossing of the MC's shock at 0.6–0.7 AU. The finding is consistent with the recent paradigm according to which solar wind plasma and magnetic field tend to pile up in front of interplanetary ejecta because the expansion of the ejecta hinders the shocked solar wind plasma from deflecting effectively around the object. Also, the inferred “age” of the layer contiguous to the surface of the MC, the earliest relic of its passage through the inner heliosphere, is in agreement with general estimates.
A model for episodic degassing of an andesitic magma intrusion
Authors: Boichu Marie , Villemant Benoît , Boudon Georges
Published: July 2008

Episodic magmatic degassing has been observed at numerous volcanoes, especially those of intermediate composition. It can span timescales from years to decades. Here we propose a physical model for the degassing of a shallow magma intrusion to explain this phenomenon. The magma cools by convection, which leads to melt crystallization, volatile exsolution, and magma overpressure. When the pressure reaches a critical value, wall rocks fracture and the exsolved gas escapes. The intrusion then returns to the initial lithostatic pressure and a new cooling‐crystallization‐degassing cycle occurs. A series of such cycles leads to episodic degassing. The trend and timescale of the degassing process are mainly governed by magma cooling. Two degassing regimes are exhibited: an early phase with a high frequency of gas pulses and a later phase with a lower gas pulse frequency. The transition between these two regimes is caused by the viscosity increase when the magma crystallinity exceeds the crystal percolation threshold. We find that the time to this transition is dependent on magma volume, to a first approximation. Where observations are available from sustained geochemical surveillance, the model provides constraints on key aspects of the subsurface magmatic system, with estimation of the volume of an intrusion and tensile strength of the surrounding rocks. It therefore represents a relevant tool for volcanic surveillance and hazard assessment.
Increasing hurricane wave power along the U.S. Atlantic and Gulf coasts
Authors: Bromirski Peter D. , Kossin James P.
Published: July 2008

Although no clear trend in tropical cyclone (TC) generated wave height is observed, a TC wave power index (WPI) increases significantly in the Atlantic during the mid‐1990s, resulting largely from an increase in the frequency of middle‐to‐late season TCs. The WPI is related to TC strength, size, duration, and frequency and is highly correlated with the TC power dissipation index (PDI). Differences between the Atlantic and Gulf of Mexico WPIs reflect systematic changes in TC genesis regions and subsequent tracks, characterized by their relationship with the regional circulation patterns described by the Atlantic Meridional Mode. The annual wave power at near‐coastal locations is closely associated with open ocean WPI. The close association of the WPI to hurricane activity implies that under rising sea level, significant coastal impacts will increase as the PDI increases, regardless of TC landfall frequency.
Cloud field segmentation via multiscale convexity analysis
Authors: Lim Sin Liang , Daya Sagar B. S.
Published: July 2008

Cloud fields retrieved from remotely sensed satellite data resemble functions depicting spectral values at each spatial position (x,y). Segmenting such cloud fields through a simple thresholding technique may not provide any structurally significant information about each segmented category. An approach based on the use of multiscale convexity analysis to derive structurally significant regions from cloud fields is addressed in this paper. This analysis requires (1) the generation of cloud fields at coarser resolutions and (2) the construction of convex hulls of cloud fields, at corresponding resolutions by employing multiscale morphologic opening transformation and half‐plane closings with certain logical operations. The three basic parameters required from these generated multiscale phenomena in order to accomplish the structure‐based segmentation include (1) the areas of multiscale cloud fields, (2) the areas of corresponding convex hulls, and (3) the estimation of convexity measures at corresponding resolutions by employing the areas of cloud fields and areas of corresponding convex hulls. These convexity measures computed for multiscale cloud fields are plotted as a function of the resolution imposed owing to multiscale opening to derive a causal relationship. The scaling exponents derived from these graphical plots are taken as the basis for (1) determining the transition zones between the regimes and (2) segmenting the cloud fields into morphologically significant regions. We demonstrated this approach on two different cloud fields retrieved from Moderate Resolution Imaging Spectroradiometer (MODIS) data. The segmented regions from these cloud fields possess different degrees of spatial complexities. As many macroscale and microscale atmospheric fields are classified according to spatial variability indexes, the framework proposed here would supplement those existing atmospheric field classification methodologies.
Serial profiles of electrostatic potential in five New Mexico thunderstorms
Authors: Stolzenburg Maribeth , Marshall Thomas C.
Published: July 2008

Profiles of electric potential (V) integrated from balloon‐borne electric field (E) measurements are used to investigate the electrical evolution of thunderstorms over the mountains in central New Mexico. With sequential soundings through multiple storms, the time skew associated with obtaining V from a noninstantaneous sounding is also studied. The data show that a basic V profile, with a maximum above a minimum, forms in the early stage of the storm and is maintained throughout its mature stage. Series of soundings from individual storms show only a gradual evolution in the V profile from the early through the mature stage, as the extrema descend in altitude and become shallower and vertically closer together. More evolution occurs in the late stage, when the shape of the V profile reverses to have a minimum above a maximum. The 17 V(z) profiles from the mature stage of five different storms are also very similar in overall shape, suggesting that the basic shape is not significantly affected by differences in lightning flash rate among these storms. The findings indicate that the potential profile during a typical sounding in the mature stage is relatively stable, and the overall shape of the mature stage V profile does not change markedly on the time scale of a particular balloon sounding (10–30 min) through New Mexico mountain storms. Thus time‐skew problems in the V profiles are minor during a storm's mature stage.
Recent permafrost warming on the Qinghai‐Tibetan Plateau
Authors: Wu Qingbai , Zhang Tingjun
Published: July 2008

Permafrost temperature monitoring through 10 boreholes up to 10.7 m depth has been conducted half‐monthly from 1996 through 2006 along the Qinghai‐Tibetan Highway. The primary results show that the long‐term mean annual permafrost temperatures at 6.0 m depth vary from −0.19°C at the Touerjiu Mountains (TM1) site to −3.43°C at Fenghuo Mountain (FH1) site, with an average of about −1.55°C from all 10 sites over the period of their records, indicating permafrost is relatively warm on the Plateau. Mean annual permafrost temperatures at 6.0 m depth have increased 0.12°C to 0.67°C with an average increase of about 0.43°C during the past decade. Over the same period, mean annual air temperatures from four National Weather Service Stations show an increase of about 0.6°C to 1.6°C, generally sufficient to account for the permafrost warming although other factors, such as changes in snow cover and soil moisture conditions, may also play important roles in permafrost warming. Increase in summer rainfall and decrease in winter snowfall may be cooling factors to the underlying soils, offsetting less degree of permafrost warming compared with the magnitude of air temperature increase. Permafrost temperatures at 6.0 m depth increased year‐around with most of the increase happened in spring and summer. Winter air temperature has increased 2.9°C to 4.2°C from 1995 through 2005, which may account for significant spring and summer permafrost warming at 6.0 m depth due to three to six month time lag. However, there were no significant trends of air temperature change in other seasons. Further investigation, especially comprehensive monitoring, is needed to better comprehend the physical processes governing the thermal regime of the active layer and permafrost on the Qinghai‐Tibetan Plateau.
Mid‐Holocene ENSO: Issues in quantitative model‐proxy data comparisons
Authors: Brown J. , Tudhope A. W. , Collins M. , McGregor H. V.
Published: July 2008

Evaluation of climate model simulations using observed data contributes to the assessment of confidence in model predictions of future climate change. The mid‐Holocene represents an opportunity to evaluate model simulations of El Niño–Southern Oscillation (ENSO) in comparison with coral proxy evidence of reduced ENSO amplitude. Quantitative comparisons between coral records and model output have been limited by (1) the use of different measures of ENSO amplitude, (2) possible sampling of natural variability in short records, and (3) uncertainty about the stationarity of the relationship between central Pacific sea surface temperature (SST) variability and ENSO signals at the coral site. We examine these issues using modern and fossil coral records from the western Pacific and model simulations of preindustrial and mid‐Holocene climate. As a measure of ENSO amplitude, the standard deviation is found to be preferable to event frequency or size as event‐based measures are highly dependent on the choice of threshold and may be unreliable for a small number of events. Model ENSO amplitude is found to be strongly dependent on the choice of averaging period, with calendar year averages smoothing the seasonal ENSO signal. A relatively robust relationship between SST variability in the NINO3.4 region and the ENSO SST and precipitation anomalies archived in corals is demonstrated for the instrumental period and for a set of model simulations. Remaining uncertainty about changes in ENSO teleconnections under paleoclimate conditions implies the need for additional proxy records from ENSO‐sensitive regions before quantitative reconstructions of ENSO amplitude can be used to evaluate model sensitivity.
Riverine Flow and Lake Level Variability in Southern South America
Authors: Depetris P. J. , Pasquini A. I.
Published: July 2008

Considerable attention was directed during the 1920s to the remote connection that appeared to exist between the Southern Oscillation (SO) and anomalous rainfall over southern Brazil, Paraguay, and northern Argentina [Mossman, 1924]. It was Gilbert Thomas Walker's group, then in India seeking the prediction of monsoonal dynamics, that made the observation—seen with skepticism—that high volumes of flow along the Paraná River, as measured at the downstream Rosario (Argentina) gauging station, tended to occur during the negative phase of the SO, when surface level pressure (SLP) was anomalously high around Australia [Bliss, 1928]. Such high surface level pressures, when associated with unusual low pressure along South America's coast, tended to cause droughts in regions bordering the equatorial Pacific Ocean and heavy rainfall in other parts of the Americas and the world.
Cold Regions Hydrology and Water Management: Bridging the Gap: Prediction of Water Resources in Mountain and Northern Canada: What is Needed, What Can be Done—An IP3 Users/Stakeholders Community Workshop; Canmore, Alberta, Canada, 18–19 March 2008
Authors: Fridell Julie , Pomeroy John
Published: July 2008

Improved Processes and Parameterisation for Prediction in Cold Regions (IP3) is a research network funded by the Canadian Foundation for Climate and Atmospheric Sciences (http://www.usask.ca/ip3). With more than 80 members across Canada, the United States, and Europe, IP3 is devoted to the study and prediction of surface water, weather, and climate systems in cold regions, particularly Canada's Rocky Mountains and western Arctic. IP3 contributes to better understanding of ungauged basin streamflow, snow and water supplies, Arctic Ocean freshwater inputs, and sustainable management of mountain and northern water resources. These issues are important to agriculture, recreation, industrial development, regional planning, policy making, streamflow forecasting, and environmental conservation in the Canadian Rockies, prairies, and north.
The Demise of Print
Authors: Albarède Francis , Constable Cathy , Duffy Chris , Fuselier Stephen , Penner Joyce , Preller Ruth , Strobel Darrell , Suyehiro Kiyoshi , Verstraete Michel
Published: July 2008

No print subscriptions to AGU journals will be available after 2010. Since 2002, when the electronic journal was made the version of record, it was clear that the day would come when the print version would be unsustainable.

First, the printed version would increasingly differ from the electronic one. One of AGU's goals for the conversion to electronic delivery was to take the journal beyond the printed page. More authors are taking advantage of the ability to use animations, video, and even interactive material—none of which can be part of the printed journal. Also, more authors are choosing to have color only in the electronic journal.
Munro Receives 2008 David Perlman Award for Excellence in Science Journalism‐News
Authors: Honeyman Teresa , Munro Margaret
Published: July 2008

Margaret Munro received the David Perlman Award at the 2008 Joint Assembly Honors Ceremony, which was held on 29 May 2008 in Fort Lauderdale, Fla. Munro was honored for “Ice Shelf Collapse Sends Chill,” which chronicles the breakup in under an hour in August 2005 of a huge Arctic ice shelf, aptly portraying the monumental scale of the event, the suspicion that climate change was the cause, and the implications for the future.
Three‐hundred‐year hydrological changes in a subtropical estuary, Rookery Bay (Florida): Human impact versus natural variability
Authors: Donders Timme H. , Gorissen P. Martijn , Sangiorgi Francesca , Cremer Holger , Wagner‐Cremer Friederike , McGee Vicky
Published: July 2008

The coastal wetland ecosystems in Florida are highly sensitive to changes in freshwater budget, which is driven by regional sea surface temperature, tropical storm activity, and the El Niño–Southern Oscillation (ENSO). Although studying Florida wetlands is pivotal to the understanding of these interacting climate systems, wetland dynamics have been severely altered by recent land use and drainage activities. To gather insights into the natural variability of the coastal ecosystems in Florida versus the effects of anthropogenic impact in the area, we present a 300‐year record of changes in the hydrological cycle from a shallow subtropical estuary (Rookery Bay) on the western shelf of Florida, Gulf of Mexico. Palynological (pollen and organic‐walled dinoflagellate cysts), diatom, and sedimentological analyses of a sediment core reveal significant changes in past runoff and wetland development. The onset and development of human impact in Florida are evident from high influx of Ambrosia pollen at about A.D. 1900, indicative of land clearance and disturbed conditions. To date, this is the southernmost record of Ambrosia increase related to human impact in the United States. Wetland drainage and deforestation since A.D. 1900 are evident from the reduced freshwater wetland and pine vegetation, and lower abundances of phytoplankton species indicative of lagoonal and brackish conditions. High runoff after A.D. 1900 relates to increased erosion and may correspondingly reflect higher impact from hurricane landfalls in SW Florida. Several phases with high siliciclastic input and greater wetland pollen abundance occur that predate the human impact period. These phases are interpreted as periods with higher runoff and are likely related to regional longer‐term climate variability.
Direct measurements of impact devolatilization of calcite using a laser gun
Authors: Ohno Sohsuke , Kadono Toshihiko , Ishibashi Ko , Kawaragi Ko , Sugita Seiji , Nakamura Eizo , Matsui Takafumi
Published: July 2008

Devolatilization of volatile‐bearing minerals caused by hypervelocity impacts is believed to have played important roles in atmosphere formation and the evolution of surface environments of terrestrial planets. The threshold shock pressure required for devolatilization is one of the most important parameters. In this study, we show a new experimental method to directly measure impact Devolatilization of volatile‐bearing minerals using a laser gun, which can avoid the problems of previous studies. We applied this method to the devolatilization of calcite. The results show that the shock pressure required for incipient devolatilization of calcite is lower than 24.9 ± 2.6 GPa which is significantly lower than previous experimental studies.
Variable winds on Venus mapped in three dimensions
Authors: Sánchez‐Lavega A. , Hueso R. , Piccioni G. , Drossart P. , Peralta J. , Pérez‐Hoyos S. , Wilson C. F. , Taylor F. W. , Baines K. H. , Luz D. , Erard S. , Lebonnois S.
Published: July 2008

We present zonal and meridional wind measurements at three altitude levels within the cloud layers of Venus from cloud tracking using images taken with the VIRTIS instrument on board Venus Express. At low latitudes, zonal winds in the Southern hemisphere are nearly constant with latitude with westward velocities of 105 ms−1 at cloud‐tops (altitude ∼ 66 km) and 60–70 ms−1 at the cloud‐base (altitude ∼ 47 km). At high latitudes, zonal wind speeds decrease linearly with latitude with no detectable vertical wind shear (values lower than 15 ms−1), indicating the possibility of a vertically coherent vortex structure. Meridional winds at the cloud‐tops are poleward with peak speed of 10 ms−1 at 55° S but below the cloud tops and averaged over the South hemisphere are found to be smaller than 5 ms−1. We also report the detection at subpolar latitudes of wind variability due to the solar tide.