bluuebunny/crossref_metadata_2025 huggingface dataset:
Randomly coloring sparse random graphs with fewer colors than the maximum degree
Authors: Dyer Martin , Flaxman Abraham D. , Frieze Alan M. , Vigoda Eric
Published: September 2006

We analyze Markov chains for generating a randomk‐coloring of a random graphGn,d/n. When the average degreedis constant, a random graph has maximum degreeΘ(logn/log logn), with high probability. We show that, with high probability, an efficient procedure can generate an almost uniformly randomk‐coloring whenk=Θ(log logn/log log logn), i.e., with many fewer colors than the maximum degree. Previous results hold for a more general class of graphs, but always require more colors than the maximum degree. © 2006 Wiley Periodicals, Inc. Random Struct. Alg., 2006
Concentration for self‐bounding functions and an inequality of Talagrand
Authors: McDiarmid Colin , Reed Bruce
Published: September 2006

We see that the entropy method yields strong concentration results for general self‐bounding functions of independent random variables. These give an improvement of a concentration result of Talagrand much used in discrete mathematics. © 2006 Wiley Periodicals, Inc. Random Struct. Alg., 2006
Using Biological Inspiration to Engineer Functional Nanostructured Materials
Authors: Wendell David W. , Patti Jordan , Montemagno Carlo D.
Published: September 2006

Humans have always looked to nature for design inspiration, and material design on the molecular level is no different. Here we explore how this idea applies to nanoscale biomimicry, specifically examining both recent advances and our own work on engineering lipid and polymer membrane systems with cellular processes.
System dynamics and organizational interventions
Authors: Rouwette Etiënne A. J. A. , Vennix Jac A. M.
Published: September 2006

System dynamics models of organizational problems have been constructed since the 1950s. In the second half of the 1970s publications began appearing on explicit procedures to involve clients in the process of model construction. After about 30 years of applying and researching participative modelling approaches, it is useful to consider the extent to which these procedures have matured into a full‐blown methodology. Does client involvement in system dynamics modelling yield repeatable results? Is the procedure adequately codified, or does its success depend on the experience and skills of the practitioner? Participative modelling is often associated with beneficial process results, such as consensus and participants' commitment to results. What evidence do we have that these ‘soft’ results actually materialize? Which conditions (types of interventions and client or problem characteristics) are especially favourable to these outcomes? The paper discusses these questions and closes with a set of topics relevant for further development of participative modelling and alternative strategies to study these topics. Copyright © 2006 John Wiley & Sons, Ltd.
Second‐order intervention: enhancing organizational competence and performance
Authors: Schwaninger Markus , Janovjak Matej , Ambroz Kristjan
Published: September 2006

While most managerial interventions into organizational and business processes have the character of a direct interference, the interventions of consultants are rather indirect. They are meant to improve the organization and its performance, via a dialogue with the management. To clarify the specific role of consultants we shall introduce the concept of second‐order intervention, therewith sharpening or, in a certain sense, redefining that role. We shall revert to a case study, which refers to a System Dynamics (SD) modelling and simulation project, to illustrate how a series of second‐order interventions has opened new paths towards superior organizational competence and performance. This was an exploratory study, in the tradition of Action Research, not a hypothesis‐testing venture. Copyright © 2006 John Wiley & Sons, Ltd.
The social dimension of system dynamics‐based modelling
Authors: Vriens Dirk , Achterbergh Jan
Published: September 2006

In this paper, the social dimension of system dynamics (SD)‐based modelling is explored. Three manifestations of this dimension are identified: SD‐models are made of social systems, they are built in social systems, and SD‐models are built for social systems. The paper (1) explains the nature of these three manifestations of the social dimension, (2) discusses problems emerging from them and (3) gives an overview of knowledge, required to deal with these problems. Copyright © 2006 John Wiley & Sons, Ltd.
Clinical Significance of Lymph Node Metastasis of Thyroid Papillary Carcinoma Located in One Lobe
Authors: Ito Yasuhiro , Jikuzono Tomoo , Higashiyama Takuya , Asahi Shuji , Tomoda Chisato , Takamura Yuuki , Miya Akihiro , Kobayashi Kaoru , Matsuzuka Fumio , Kuma Kanji , Miyauchi Akira
Published: September 2006

Background

Previous studies have shown that lymph node metastasis can be of prognostic value. In this study, we investigated the clinical significance of node metastasis focusing on metastasis in the central compartment for patients with papillary carcinoma located in one lobe.

Patients and Methods

We investigated the frequency of lymph node metastasis in 759 patients with papillary carcinoma to determine whether and how such metastasis affects disease‐free survival (DFS).

Results

Central node metastasis was observed in 63% of patients, and the frequency was increased in relation to tumor size. The frequency of lateral node metastasis was 62.0%, which was also directly related to tumor size. On multivariate analysis of cases showing tumor larger than 1 cm, central node metastasis was recognized as an independent prognostic factor of DFS. The frequency of metastasis to the paratracheal nodes contralateral to the tumor was drastically elevated for tumors larger than 1 cm, but metastasis to this region did not independently predict worse DFS.

Conclusion

Central node metastasis independently predicts a worse DFS for patients with papillary carcinoma larger than 1 cm.
STD and TRNOESY NMR studies for the epitope mapping of the phosphorylation motif of the oncogenic protein β‐catenin recognized by a selective monoclonal antibody
Authors: Megy Simon , Bertho Gildas , Gharbi-Benarous Josyane , Baleux Françoise , Benarous Richard , Girault Jean-Pierre
Published: September 2006

The interaction of the P‐β‐Cat19–44 peptide, a 26 amino acid peptide (K19AAVSHWQQQSYLDpSGIHpSGATTTAP44) that mimics the phosphorylated β‐Catenin antigen, has been studied with its monoclonal antibody BC‐22, by transferred nuclear Overhauser effect NMR spectroscopy (TRNOESY) and saturation transfer difference NMR (STD NMR) spectroscopy. This antibody is specific to diphosphorylated β‐Catenin and does not react with the non‐phosphorylated protein. Phosphorylation of β‐Catenin at sites Ser33 and Ser37 on the DSGXXS motif is required for the interaction of β‐Catenin with the ubiquitin ligase SCFβ‐TrCP. β‐TrCP is involved in the ubiquitination and proteasome targeting of the oncogenic protein β‐Catenin, the accumulation of which has been implicated in various human cancers. The three‐dimensional structure of the P‐β‐Cat19–44 in the bound conformation was determined by TRNOESY NMR experiments; the peptide adopts a compact structure in the presence of mAb with formation of turns around Trp25 and Gln26, with a tight bend created by the DpS
33GIHpS
37 motif; the peptide residues (D32‐pS37) forming this bend are recognized by the antibody as demonstrated by STD NMR experiments. STD NMR studies provide evidence for the existence of a conformational epitope containing tandem repeats of phosphoserine motifs. The peptide's epitope is predominantly located in the large bend and in the N‐terminal segment, implicating bidentate association. These findings are in excellent agreement with a recently published NMR structure required for the interaction of β‐Catenin with the SCFβ‐TrCP protein.
Short-lived mafic magmatism at 560–570 Ma in the northern Norwegian Caledonides: U–Pb zircon ages from the Seiland Igneous Province
Authors: ROBERTS R. J. , CORFU F. , TORSVIK T. H. , ASHWAL L. D. , RAMSAY D. M.
Published: September 2006

The Seiland Igneous Province (SIP) of northern Norway comprises a suite of mainly gabbroic plutons, with subordinate ultramafic, syenitic and felsic intrusions. Several intrusions from the Seiland Igneous Province have been dated by ID-TIMS U–Pb zircon and monazite analyses. The Hasvik Gabbro on the island of Sørøy, previously assigned an age of 700±33 Ma by Sm–Nd, yields a U–Pb zircon age of 562±6 Ma, within error of the Storelv Gabbro (569±5 Ma) and a diorite associated with the Breivikbotn Gabbro (571±4 Ma). Various intrusions on the Øksfjord peninsula give nearly identical ages of 565±9 Ma (gabbro), 566±4 Ma (monzonite), 565±5 Ma (monzodiorite), 570±9 Ma (norite), and 566±1 Ma (orthopyroxenite). These ages overlap with those from Sørøy, and define a single and short-lived period of gabbroic (to felsic) magmatism for the region between 570 and 560 Ma, pre-dating a subordinate episode of alkalic magmatism at 530–520 Ma. The U–Pb ages contradict the previous geochronological interpretation for the Finnmark area, which implied a period of 250 m.y. for the emplacement of the SIP intrusions. The new age data also clearly distinguish the Seiland intrusions, emplaced into the Sørøy Group metasediments of the Kalak Nappe Complex, from several older granitic intrusions (c. 850 to 600 Ma) that cut the Sørøy Group farther east and south. The coincident ages of the different Seiland intrusive bodies also contradict the previous structural model for the area, which posits that the different gabbro bodies were emplaced at intervals, with compressional deformation affecting the gabbros between periods of intrusion. The short time span between the main plutonic phases strongly suggests that the mechanism for the emplacement of mafic magma operated in a single, probably extensional, tectonic regime. The mafic intrusions were later deformed and metamorphosed to at least amphibolite facies, most likely by the Scandian (420 Ma) phase of the Caledonian Orogeny.
A physiological analysis of oilseed rape yields: Past and future
Authors: BERRY P. M. , SPINK J. H.
Published: September 2006

Oilseed rape yields on farms have not increased in several countries, including the UK, since the mid 1980s. This may be because the yield potential for the environment in these countries has been reached, or due to a lack of genetic improvement, or due to changes in the environment of the growing crop caused by crop management practices. The present paper investigates which of these factors may be causing the yield of farm crops in the UK to remain at 3 t/ha. The yield potential for the UK that would be possible by combining the best characteristics that have been observed with the best crop management is estimated to be significantly greater than average farm yields at 6·5 t/ha (90 g/kg moisture content). In order to achieve 6·5 t/ha, a crop would have a flower cover of less than 0·4 to facilitate the production of 130000 seeds/m2. Seed filling must last 46 days and have a solar radiation use efficiency of 0·75 g of seed/MJ. A tenth of the yield must come from stem reserves and the seed weight must be 5·0 mg. All of these characteristics have been achieved; therefore the challenge lies in combining these traits within the same crop. The ultimate yield potential for water retentive soils in the UK is estimated at 9·2 t/ha. This would require new characteristics to be bred into the crop and represents a long-term target. In the UK, new oilseed rape varieties are introduced each year and the yield of these varieties under optimum growing conditions is estimated to have increased by 62 kg/ha/year between 1978 and 2005. Lack of genetic improvement is therefore unlikely to explain the halt in farm yields. There have been trends for farm crops to be grown in shorter rotations, established using minimal cultivations rather than ploughing and to receive less nitrogen fertilizer. Sulphur applications have increased, but probably have not kept pace with the reduction in deposition from the atmosphere. Fungicide applications to farm crops are less than applied to the variety testing system and are unlikely to offer complete disease control. It is concluded that a combination of these crop management factors has caused the halt in yield improvement on UK farms.
GETTING READY FOR THE MARRIAGE MARKET? THE ASSOCIATION BETWEEN
DIVORCE RISKS AND INVESTMENTS IN ATTRACTIVE BODY MASS AMONG MARRIED EUROPEANS
Authors: LUNDBORG PETTER , NYSTEDT PAUL , LINDGREN BJÖRN
Published: September 2006

This article explores to what extent married middle-aged individuals in Europe
are governed by the risk of experiencing divorce, when shaping their physical
appearance. The main result is that divorce risks, proxied by national divorce
rates, are negatively connected to body mass index (BMI) among married
individuals but unrelated to BMI among singles. Hence, it seems that married
people in societies where divorce risks are high are more inclined to invest in
their outer appearance. One interpretation is that high divorce rates make
married people prepare for a potential divorce and future return to the marriage
market.
Growth and colour development of some surface ripening bacteria with Debaryomyces hansenii on aseptic cheese curd
Authors: Mounier Jérôme , Irlinger Françoise , Leclercq-Perlat Marie-Noëlle , Sarthou Anne-Sophie , Spinnler Henry-Eric , Fitzgerald Gerald F , Cogan Timothy M
Published: September 2006

The growth of five bacteria isolated from red-smear cheeses, Brevibacterium aurantiacum, Corynebacterium casei, Corynebacterium variabile, Microbacterium gubbeenense and Staphylococcus saprophyticus in mixed cultures with Debaryomyces hansenii on aseptic model cheese curd at 10 and 14 °C was investigated. At both temperatures, C. casei and Micro. gubbeenense had a longer lag phase than C. variabile, Brevi. aurantiacum and Staph. saprophyticus. In all cultures, lactose was utilised first and was consumed more rapidly at 14 °C than at 10 °C, i.e., 6 d at 14 °C and 10 d at 10 °C. This utilisation coincided with the exponential growth of Deb. hansenii on the cheese surface. Lactate was also used as a carbon source and was totally consumed after 21 d at 14 °C and ~90% was consumed after 21 d at 10 °C regardless of the ripening culture. Small differences (<0·5 pH unit) in the surface-pH during ripening were noticeable between ripening cultures. Differences in the colour development of the mixed cultures with the yeast control were only noticeable after 15 d for Brevi. aurantiacum and after 21 d for the other bacteria. Regardless of the organisms tested, colour development and colour intensity were also greater at 14 °C than at 10 °C. This study has provided useful information on the growth and contribution to colour development of these bacteria on cheese.
Effects of ventilation rate and of dietary protein level in an intensive dairy sheep system on the features of Canestrato Pugliese cheese
Authors: Albenzio Marzia , Santillo Antonella , Caroprese Mariangela , Marino Rosaria , Annicchiarico Giovanni , Sevi Agostino
Published: September 2006

Effects of ventilation rate and of dietary protein level in an intensive dairy sheep system on the features of Canestrato Pugliese cheese were studied. Cheeses were manufactured from the bulk milk obtained from ewes subjected to four different experimental treatments: (1) low dietary crude protein (CP) of 13% in dry matter (DM) at a low ventilation rate (23·5 m3/h per ewe) (LPLV); (2) low dietary CP at a moderate ventilation rate (47 m3/h per ewe) (LPMV), (3) moderate dietary CP of 16% DM at a low ventilation rate (MPLV); and (4) moderate dietary CP dietary at a moderate ventilation rate (MPMV). Bulk milk and cheeses (at 1, 15, 45 and 90 d of ripening) were analysed for chemical composition, N fractions and plasmin-plasminogen activities. The pH 4·6-soluble and insoluble N fractions were analysed by urea-PAGE. Bulk milk from ewes receiving the low CP diet displayed higher casein and lower urea contents. Ewes subjected to the low ventilation rate displayed a higher plasminogen activity in milk, whereas no differences emerged among treatments in the conversion of zymogen to plasmin. During ripening the plasmin-plasminogen system in cheese did not display significant changes across treatments. At 90 d of ripening, the cheese produced with milk from ewes receiving the low CP diet and exposed to the low ventilation rate displayed more markedly stained bands in the area of γ-caseins in pH 4·6-insoluble N fraction. As from 15 d of ripening, the pH 4·6-soluble fraction showed a greater number of bands in the LPMV and MPMV than in the LPLV and MPLV cheeses. The results showed that Canestrato Pugliese cheese manufactured with milk from ewes fed the low CP diet and exposed to the moderate ventilation rate was characterized by higher protein and casein content in the fresh cheese and by a greater proteolysis after 90 d of ripening.
Use and relevance of a bovine mammary gland explant model to study infection responses in bovine mammary tissue
Authors: Rabot Aline , Wellnitz Olga , Meyer Heinrich H D , Bruckmaier Rupert M
Published: September 2006

Our aim was to develop an explant model to define more precisely the early response of bovine mammary epithelial cells to infection. Therefore we investigated the mRNA expression encoding for some soluble immunological factors in lipopolysaccharide (LPS)-treated bovine mammary gland explants. Explants were taken out from the mammary gland of eight lactating cows after slaughter then incubated with LPS (10 μg/ml) for 6 h. The mRNA expression of α-lactalbumin (α-la), various cytokines, tumour necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-8, and two immunoglobulin receptors, the neonatal Fc receptor (FcRn) and polymeric immunoglobulin receptor (pIGR), were assessed with qPCR before and after 3 h and 6 h of LPS challenge. Both immunoglobulin receptors and α-la increased at 3 h then recovered their initial level at 6 h whereas IL-1β, IL-6 and IL-8 increased only after 6 h (P<0·05). Surprisingly, TNF-α transcripts did not show any regulation in response to the LPS treatment. We nevertheless concluded that our model was valid to examine the short-term response of mammary epithelial cell challenged with LPS.
Identification of a single nucleotide polymorphism at intron 16 of the caprine Acyl-Coenzyme A: diacylglycerol acyltransferase 1 (DGAT1) gene
Authors: Angiolillo Antonella , Amills Marcel , Urrutia Baltasar , Doménech Anna , Sastre Yolanda , Badaoui Bouabid , Jordana Jordi
Published: September 2006

The DGAT1 gene encodes a microsomal enzyme that catalyses the only committed step in triacylglycerol synthesis by joining diacylglycerol and fatty acyl coenzyme A. In cattle, a K232A substitution in the DGAT1 molecule has a significant effect on enzyme activity and milk fat content. The prominent role of this gene in lipid metabolism led us to undertake the structural characterization of DGAT1 in goats. In this way, we have sequenced a 1552 bp fragment of the goat DGAT1 cDNA, which encompasses most of the coding sequence (from exon 1 to 17), and a genomic fragment covering exons 12 to 17. Multiple alignment of the goat DGAT1 sequences revealed the existence of a single nucleotide polymorphism (SNP) involving a T to C substitution at intron 16. We optimized a primer extension based genotyping method that allowed us to determine that the C variant is a minority allele with frequencies ranging from 0·062 (Murciano-Granadina) to 0·109 (Malagueña). This SNP, although not expected to have any functional effect, might be useful as a genetic marker in association studies to detect additional DGAT1 polymorphisms which might influence fat milk content and other traits of economic interest.
Laryngeal cancer after topical mitomycin C application
Authors: Agrawal N , Morrison G A
Published: September 2006

Mitomycin C is part of the mitomycin group of antibiotics and has found use in medicine in the treatment of various cancers, including those of the head and neck. In recent years, it has gained popularity as a topical treatment to prevent scar formation in the larynx and choanae in paediatric and adult inflammatory processes. Also, this alkylating agent is potentially a potent carcinogen. We report the first case in the world literature of laryngeal carcinoma in a non-smoking adult, which may have been induced by topical mitomycin C application to a glottic web. We discuss the mechanism of action of this drug, and we advise caution on its use for benign laryngeal pathologies.
Capitalising on Catastrophe: Reinvigorating the Japanese State with Moral Values through Education following the 1923 Great Kantô Earthquake
Authors: BORLAND JANET
Published: September 2006

Sudden onset natural disasters such as earthquakes are absolute physical and psychological levellers which spare no one from the event itself or the aftermath. The resulting physical devastation of a city and the psychological weakening of a population, however, also present opportunities. The opportunity to reorder society is unparalleled by any other historical event except perhaps war and with increasing regularity throughout much of the twentieth century, nation states have used disasters as a pretext to secure long held political goals. In September 1923, the devastation of Tokyo as a result of the Great Kantô Earthquake presented a significant opportunity to reorder Japanese society both on a physical and psychological level. In the post-disaster reconstruction period, the government was quick to capitalise on this catastrophe.
The Meiji Earthquake: Nature, Nation, and the Ambiguities of Catastrophe
Authors: CLANCEY GREGORY
Published: September 2006

On October 28, 1891, one of the most powerful earthquakes in modern Japanese history rocked the main island of Honshu from Tokyo to Osaka. Centered on the populous Nōbi Plain north of Nagoya, this was the first daishinsai (‘great earthquake disaster’) of the Meiji era, and the strongest to visit central Japan in 37 years. The Great Nōbi Earthquake killed only 7–8,000 people (compared to the over 100,000 destined to die in the Great Kantō Earthquake of 1923), mostly inhabitants of towns and villages in Nagoya's hinterland. But its breadth and power were unprecedented in the memories of most Japanese, and the event became the subject of many dozens of books, newspaper and journal articles, paintings and woodblock prints, and even images on fans, plates, and lampshades. This was Japan's first truly national natural catastrophe. It was national in the sense that it was deemed by many of its narrators to have affected the new nation-state directly, and a nationalizing discourse of alarm, regret, recrimination, sympathy, and even patriotism was generated around it by a newly-consolidating modern print media.
Indonesian Corporations, Cronyism, and Corruption
Authors: BROWN RAJESWARY AMPALAVANAR
Published: September 2006

This paper is concerned with cronyism and corruption in the Indonesian corporate economy. It employs detailed corporate evidence, verifying the inter-penetration of diverse political, bureaucratic and economic institutions. Although the emphasis is on the 1990s, the historical developments since 1950 within the institutions of the presidency, the military, private Chinese and pribumi corporations, as well as state-owned enterprises, are analysed in detail to identify the sources of this corruption. Equally important are the failures of the bureaucracy, the legal infrastructure, in curtailing corruption and introducing effective corporate governance. The relationship of this spiralling corruption to the 1997 financial crisis is clear. The final section is concerned with the reforms introduced after the crisis. This section also appraises the differences in corporate structures and networks between Western companies and the Indonesian conglomerates, identifying the need for institutional change.
Strong and weak media? On the Representation of ‘Terorisme’ in Contemporary Indonesia
Authors: FOX RICHARD
Published: September 2006

It is as if bombings have become a trend in Indonesian society.

Tempo Interaktif, 25 December 2000.

To put it crudely: because the languages of Third World societies – including, of course, the societies that social anthropologists have traditionally studied – are ‘weaker’ in relation to Western languages (and today, especially to English), they are more likely to submit to forcible transformation in the translation process than the other way around.

Talal Asad (1986: 157–8)
Epidemiology of parasitic protozoan infections in Soay sheep (Ovis ariesL.) on St Kilda
Authors: CRAIG B. H. , PILKINGTON J. G. , KRUUK L. E. B. , PEMBERTON J. M.
Published: September 2006

The feral Soay sheep (Ovis ariesL.) population on Hirta, St Kilda, is host to a diverse component parasite community, but previous parasitological studies of the population have only focussed on the metazoan species. This paper reports the first epidemiological study of the protozoan species comprisingCryptosporidium parvum,Giardia duodenalisand 11 species ofEimeriain Soay sheep across 3 years of varying host population density. Prevalence and intensity of almost all species of protozoa significantly decreased with host age, with the exception ofE. granulosa, which increased in prevalence with host age. The prevalence ofC. parvumappeared to vary positively with host population density but that ofG. duodenalisdid not vary significantly with density. Most species ofEimeriashowed a distinct lag in infection level following the host population crash of 2002, taking up to 2 years to decrease. MixedEimeriaspecies intensity and diversity were highest in 2002, a year of low host density. Parasite diversity decreased with host age and was higher in males. There were 5 positive pair-wise associations between protozoa species in terms of prevalence. The results of this study highlight the potential for protozoal infection to shape the evolution of parasite resistance in wild host populations harbouring diverse parasite species.
Looking towards the detection of exoearths with SuperWASP
Authors: Street R.A. , Christian D.J. , Clarkson W.I. , Cameron A.C. , Enoch B. , Evans A. , Fitzsimmons A. , Haswell C.A. , Hellier C. , Hodgkin S.T. , Horne Keith , Irwin J. , Keenan F.P. , Kane S.R. , Lister T.A. , Norton A.J. , Osborne J. , Pollacco D. , Ryans R. , Skillen I. , West R.G. , Wheatley P.J. , Wilson D.
Published: September 2006

The WASP consortium is conducting an ultra-wide field survey of stars between 8–15 mag from both hemispheres. Our primary science goal is to detect extra-solar ‘hot-Jupiter’-type planets that eclipse (or transit) bright host stars and for which further detailed investigation will be possible. We summarize the design of the SuperWASP instruments and describe the first results from our northern station SW-N, sited in La Palma, Canary Islands. Our second station, which began operations this year, is located at the South African Astronomical Observatory. Between April and September, 2004, SW-N continuously observed ~6.7 million stars. The consortium's custom-written, fully automated data reduction pipeline has been used to process these data, and the information is now stored in the project archive, held by the Leicester database and archive service (LEDAS). We have applied a sophisticated, automated algorithm to identify the low-amplitude (~0.01 mag), brief (~few hours) signatures of transiting exoplanets. In addition, we have assessed each candidate in the light of all available catalogue information in order to reject data artefacts and astrophysical false positive detections. The highest priority candidates are currently being subjected to further observations in order to select the true planets. Once the exoplanets are confirmed, a host of exciting opportunities are open to us. In this paper, we describe two techniques that exploit the transits in order to detect other objects within the same system. The first involves determining precise epochs for a sequence of transit events in order to detect the small timing variations caused by the gravitational pull of other planets in the same system. The second method employs ultra-high precision photometry of the transits to detect the deviations caused by the presence of exoplanetary moons. Both of these techniques are capable of detecting objects the size of terrestrial planets.
Characterization of exceptionally strong mesospheric wave events using all‐sky and zenith airglow observations
Authors: Smith Steven M. , Scheer Jürgen , Reisin Esteban R. , Baumgardner Jeffrey , Mendillo Michael
Published: September 2006

Two unusually clear mesospheric gravity wave events were observed by the Boston University all‐sky imager and the Argentine airglow spectrometer on two consecutive nights at the El Leoncito Observatory, Argentina (31.8°S, 69.3°W), during August 2001. Both events exhibited brightness amplitudes an order of magnitude above typical values. The first event had the appearance of a large‐amplitude (>60% in OH(6‐2), 22% in O2, and 37% in O(1S) emissions (peak to peak), compared to 1–5% typically), upward propagating gravity wave with pronounced nonlinear behavior. The waves also showed noticeably curved wavefronts, indicating that they had originated from a relatively small source region within ∼180 km of El Leoncito. Estimates of the vertical flux of horizontal energy and momentum for the wave event in the OH and O2 emissions were very large compared to typical values, and they also indicated a high degree of flux divergence over the nominal 8 km altitude between the two layers. The second event occurred on the following night and exhibited a frontal morphology and behavior consistent with an internal ducted gravity wave showing nonlinear behavior akin to a mesospheric bore. The disturbance also had several interesting characteristics; in particular, the propagation speed decreased during its passage across the sky. In addition, a strong vertical temperature gradient due to the semidiurnal tide appeared to influence the occurrence of the bore event.
Magnetosphere preconditioning under northward IMF: Evidence from the study of coronal mass ejection and corotating interaction region geoeffectiveness
Authors: Lavraud B. , Thomsen M. F. , Borovsky J. E. , Denton M. H. , Pulkkinen T. I.
Published: September 2006

Motivated by recent observations and simulations of the formation of a cold and dense plasma sheet in the tail of the magnetosphere under northward interplanetary magnetic field (IMF) and of the direct influence of the plasma sheet density on the ring current strength, this paper aims at (1) highlighting how the coupling of these effects may lead to a preconditioning of the magnetosphere under northward IMF and (2) performing first tests of the validity of this hypothesis. We have analyzed superposed epoch time series of various parameters to investigate the response of the magnetosphere (as indicated by the Dst index) to the passage of coronal mass ejections (CMEs) and corotating interaction regions (CIRs). We first focused on the difference between the measured Dst signature and that predicted by a semiempirical Dst model. For both CME‐ and CIR‐driven storms the superposed epoch results show that the model Dst predictions tend to underestimate the actual storm strength (by up to 10–30%) for events that are preceded by a substantial interval of northward IMF, as opposed to those with no such preceding northward IMF. We also analyzed Los Alamos geosynchronous spacecraft data for these events. The average density and temperature measured at storm onset are substantially higher and slightly lower, respectively, for the cases with preceding northward IMF intervals. These results suggest that solar wind structures may be more geoeffective if preceded by a northward IMF interval and they are consistent with the hypothesis of a preconditioning by a cold, dense plasma sheet. A colder and denser plasma sheet may lead to a stronger ring current when that plasma is convected inward during the main phase of an ensuing storm.
Compaction of quartz sands by pressure solution using a Cole‐Cole distribution of relaxation times
Authors: Revil A. , Leroy P. , Ghorbani A. , Florsch N. , Niemeijer A. R.
Published: September 2006

Stressed water‐infiltrated silica rocks may deform by pervasive pressure solution transfer (PPST), which involves dissolution of the grain‐to‐grain contacts, transport by diffusion of the solute, and precipitation on the free surfaces of the grains. A fundamental question regarding this process is how to model rheological behavior at stresses and temperatures typical of the crust of the Earth. A Voigt‐type poroviscoplastic model is modified by using a Cole‐Cole distribution of relaxation times rather than a Dirac distribution used previously. The motivation of this choice is to account for the distribution of the grain size in the compaction of the porous aggregate assuming that this distribution obeys approximately a log normal distribution. This grain size distribution depends upon the initial grain size distribution and cataclasis in the early stage of compaction. We compared this modified viscoplastic model with the full set of experimental data obtained in various conditions of mean grain size, effective stress, and temperature by Niemeijer et al. (2002). These data provide tests of all aspects of the model, which can be considered to have no free parameters. We show the experiments of Niemeijer et al. (2002) on PPST are primarily diffusion‐limited. The grain size distributions observed for three samples imply that the distribution of the relaxation time covers 5 orders of magnitude in grain size.
The St. Lawrence polynya and the Bering shelf circulation: New observations and a model comparison
Authors: Danielson S. , Aagaard K. , Weingartner T. , Martin S. , Winsor P. , Gawarkiewicz G. , Quadfasel D.
Published: September 2006

Using 14 yearlong instrumented moorings deployed south of St. Lawrence Island, along with oceanographic drifters, we investigate the circulation over the central Bering shelf and the role of polynyas in forming and disseminating saline waters over the shelf. We focus also on evaluating the Gawarkiewicz and Chapman (1995) model of eddy production within coastal polynyas. Principal results include the following. (1) The northern central shelf near‐surface waters exhibit westward flow, carrying low‐salinity waters from the Alaskan coast in fall and early winter, with consequences for water mass formation and biological production. (2) Within the St. Lawrence polynya the freshening effect of winter advection is about half as large as the salting effect of surface brine flux resulting from freezing. (3) Brine production over the Bering shelf occurs primarily offshore, rather than within coastal polynyas, even though ice production per unit area is much larger within the polynyas. (4) We find little evidence for the geostrophic flow adjustment predicted by recent polynya models. (5) In contrast to the theoretical prediction that dense water from the polynya is carried offshore by eddies, we find negligible cross‐shelf eddy density fluxes within and surrounding the polynya and very low levels of eddy energy that decreased from fall to winter, even though dense water accumulated within the polynya and large cross‐shore density gradients developed. (6) It is possible that dense polynya water was advected downstream of our array before appreciable eddy fluxes materialized.
Alkenone producers inferred from well‐preserved 18S rDNA in Greenland lake sediments
Authors: D'Andrea William J. , Lage Melissa , Martiny Jennifer B. H. , Laatsch Abby D. , Amaral‐Zettler Linda A. , Sogin Mitchell L. , Huang Yongsong
Published: September 2006

The 18S ribosomal DNA (rDNA) sequences of haptophyte algae were successfully amplified using the polymerase chain reaction (PCR) from water filtrate, surface sediments, and a late‐Holocene sediment sample (∼1000 years old) from a group of lakes in the Søndre Strømfjord region of west Greenland. The DNA of the algal primary producer is extremely well preserved in the laminated lake sediments which have been deposited in cold (1°–2°C), anoxic, and sulphidic bottom water. Phylogenetic analyses of the Greenland haptophyte rDNA sequences suggest that alkenones in the Greenland lake sediments are produced by haptophyte algae of the class Prymnesiophyceae. The 18S rDNA sequences from the Greenland samples cluster within a distinct phylotype, differing from both marine haptophytes and from those reported previously from Ace Lake, Antarctica. The similarity of haptophyte rDNA sequences among all samples in this study suggests a single alkenone‐based temperature calibration may be applied to these lakes for at least the past 1000 years. These sedimentary archives hold great promise for high‐resolution, alkenone‐based paleotemperature reconstruction of southern west Greenland, a region sensitive to atmospheric‐oceanic climate phenomena such as the North Atlantic Oscillation (NAO).
Price elasticity reconsidered: Panel estimation of an agricultural water demand function
Authors: Schoengold Karina , Sunding David L. , Moreno Georgina
Published: September 2006

Using panel data from a period of water rate reform, this paper estimates the price elasticity of irrigation water demand. Price elasticity is decomposed into the direct effect of water management and the indirect effect of water price on choice of output and irrigation technology. The model is estimated using an instrumental variables strategy to account for the endogeneity of technology and output choices in the water demand equation. Estimation results indicate that the price elasticity of agricultural water demand is −0.79, which is greater than that found in previous studies.
Stochastic uncertainty analysis for unconfined flow systems
Authors: Liu Gaisheng , Zhang Dongxiao , Lu Zhiming
Published: September 2006

A new stochastic approach proposed by Zhang and Lu (2004), called the Karhunen‐Loeve decomposition‐based moment equation (KLME), has been extended to solving nonlinear, unconfined flow problems in randomly heterogeneous aquifers. This approach is on the basis of an innovative combination of Karhunen‐Loeve decomposition, polynomial expansion, and perturbation methods. The random log‐transformed hydraulic conductivity field (lnKS) is first expanded into a series in terms of orthogonal Gaussian standard random variables with their coefficients obtained as the eigenvalues and eigenfunctions of the covariance function of lnKS. Next, head h is decomposed as a perturbation expansion series Σh(m), where h(m) represents the mth‐order head term with respect to the standard deviation of lnKS. Then h(m) is further expanded into a polynomial series of m products of orthogonal Gaussian standard random variables whose coefficients are deterministic and solved sequentially from low to high expansion orders using MODFLOW‐2000. Finally, the statistics of head and flux are computed using simple algebraic operations on A series of numerical test results in 2‐D and 3‐D unconfined flow systems indicated that the KLME approach is effective in estimating the mean and (co)variance of both heads and fluxes and requires much less computational effort as compared to the traditional Monte Carlo simulation technique.
Solar control of pre‐termination shock energetic particle variations observed at Voyager 1
Authors: Mosley C. J. , Armstrong T. P.
Published: September 2006

We report an analysis of time variations of several Voyager 1 Low Energy Charged Particle (LECP) rate channels for 2004 mostly in the pre‐termination shock (TS) region and for 2005 in the heliosheath. Protons and oxygen ions coming from the TS during 2004 show autocorrelation peaks at approximately and full solar rotation period. We explain the apparent solar control of particle acceleration at the TS by invoking shock drift acceleration (SDA) which depends strongly on the angle ΘBn that the interplanetary magnetic field (IMF) makes with the shock surface. Preferred regions of acceleration occur where ΘBn is near 90°. IMF connection of Voyager 1 to preferred regions on the TS can enhance the access of accelerated particles. This geometrical situation is only available during 2004. Analyses of the data from 2003 and 2005 do not show peaks at or full solar rotation period.
Calibration of reflected GPS for tropical storm wind speed retrievals
Authors: Katzberg Stephen J. , Torres Omar , Ganoe George
Published: September 2006

Since 1996 when GPS reflected signals were purposefully acquired, an effort to assess the utility of these signals has been under way. It was early determined that the reflected GPS signal can be related to ocean surface wind dependent slope probability densities. Quantifying that relationship has resulted in considerable data taken at wind speeds below those associated with tropical storms. During the 2005 hurricane season, data were taken in high wind speed conditions that have been used to compare with the U.S. Navy's COAMPS model. The gridded data were used to develop a calibration for high wind speeds which also represents a measurement of apparent ocean surface slopes at L‐Band. This paper presents the results of this GPS surface reflection calibration for winds up to 35 meters per second. In addition a simple function is developed that models the mean square slope variation with surface wind speed and includes winds above 35 meters per second. This model is applied to data from Hurricanes Dennis and Isabel to demonstrate the ability of surface reflected GPS signals to yield good retrieval performance for winds at and above tropical storm strength.
Physical versus biological spring transition: 2005
Authors: Kosro P. Michael , Peterson William T. , Hickey Barbara M. , Shearman R. Kipp , Pierce Stephen D.
Published: September 2006

In 2005, the onset of spring conditions in the physics of the coastal ocean (lowered sea level, spin‐up of vertically‐sheared equatorward coastal jet) came about 50 days later than average off Newport Oregon, on May 24. There was a further delay of 50 days before the subsurface upwelled water penetrated into the anomalously stratified surface layer, becoming most available for biological activity. The warm anomaly in sea surface temperature which provided the surface cap was observed at mid‐shelf locations from Washington to central California, but it ended sooner south of Oregon. Biological impacts of these delays to several trophic levels have been reported.
A global model of mantle conductivity derived from 5 years of CHAMP, Ørsted, and SAC‐C magnetic data
Authors: Kuvshinov Alexei , Olsen Nils
Published: September 2006

We present a global 1‐D conductivity model which is obtained by analysis of five years (2001–2005) of simultaneous magnetic data from the three satellites Ørsted, CHAMP and SAC‐C. After removal of core and crustal fields as predicted by a recent field model we used non‐polar scalar and vector observations from the night‐side sector, and interpret the field residuals in terms of a large‐scale contribution from the magnetospheric ring current and its induced counterpart. We then derive transfer functions between internal (induced) and external expansion coefficients of the magnetic potential and provide globally‐averaged C‐responses in the period range between 14 hours and 4 months. Since the satellite responses are probably influenced by induction in the oceans for periods shorter than a few days, we correct the data for this effect. Interpreting the corrected responses yields a 1‐D conductivity model which is rather similar to models derived from ground‐based data.
Terrestrial gamma ray flashes and lightning discharges
Authors: Inan U. S. , Cohen M. B. , Said R. K. , Smith D. M. , Lopez L. I.
Published: September 2006

Analysis of ELF/VLF broadband data from Palmer Station, Antarctica indicates that 76% Terrestrial Gamma‐ray Flashes (TGFs) detected on the RHESSI spacecraft occur in association with lightning‐generated radio atmospherics arriving from near the footprint of RHESSI and within a few ms of the TGF. The remaining TGFs are not associated with any radio atmospheric, thus by implication CG lightning. The peak currents of TGF‐associated lightning discharges are often among the most intense from a given storm, with the degree of this association apparently varying between oceanic and land regions. The time‐integrated ELF energy of the associated sferics (and thus the lightning charge moment) exhibit much less tendency to be large. Statistical analysis of the spread in arrival time suggests a ∼2 ms variance due to factors other than geometry and measurement error.
Microbial growth and biofilm formation in geologic media is detected with complex conductivity measurements
Authors: Davis Caroline A. , Atekwana Estella , Atekwana Eliot , Slater Lee D. , Rossbach Silvia , Mormile Melanie R.
Published: September 2006

Complex conductivity measurements (0.1–1000 Hz) were obtained from biostimulated sand‐packed columns to investigate the effect of microbial growth and biofilm formation on the electrical properties of porous media. Microbial growth was verified by direct microbial counts, pH measurements, and environmental scanning electron microscope imaging. Peaks in imaginary (interfacial) conductivity in the biostimulated columns were coincident with peaks in the microbial cell concentrations extracted from sands. However, the real conductivity component showed no discernible relationship to microbial cell concentration. We suggest that the observed dynamic changes in the imaginary conductivity (σ″) arise from the growth and attachment of microbial cells and biofilms to sand surfaces. We conclude that complex conductivity techniques, specifically imaginary conductivity measurements are a proxy indicator for microbial growth and biofilm formation in porous media. Our results have implications for microbial enhanced oil recovery, CO2 sequestration, bioremediation, and astrobiology studies.
An analytical model to relate the vertical root distribution to climate and soil properties
Authors: Laio Francesco , D'Odorico Paolo , Ridolfi Luca
Published: September 2006

We propose an analytical model to relate the vertical distribution of plant roots in water controlled ecosystems to the local climatic and pedologic conditions. We find that the shape of the root profile is determined by the distribution of the incoming rainfall pulses, and that the rooting systems are deeper where the soils are coarse‐textured and the evaporative demand slightly exceeds precipitation.
Multiple drugbinding sites on the R482G isoform of the ABCG2 transporter
Authors: Clark R , Kerr I D , Callaghan R
Published: September 2006

Background & Purpose:

Drug‐resistant cancer cells frequently display efflux pumps such as P‐glycoprotein (P‐gp), the multidrug resistance associated protein (MRP1) or the transporter ABCG2. These transporters are each capable of mediating the active efflux of numerous anticancer drugs and display relatively distinct substrate preferences. The last, most recently discovered member, ABCG2, plays a major role in resistance in several types of cancer and the precise pharmacology of this multidrug transporter remain unresolved as does the nature of substrate binding.

Experimental Approach:

Plasma membranes from insect cells expressing ABCG2 were used to characterise binding of [3H]daunomycin to the multidrug transporter. The kinetics of association and dissociation for this substrate and several other compounds were also determined in this experimental system.

Key Results:

The dissociation constant for [3H]daunomycin binding was 564±57 nM and a Hill slope of 1.4 suggested cooperative binding. Doxorubicin, prazosin and daunomycin completely displaced the binding of radioligand, while mitoxantrone and Hoechst 33342 produced only a partial displacement. Analysis of the dissociation rates revealed that [3H]daunomycin and doxorubicin bind to multiple sites on the transporter.

Conclusions:

Both kinetic and equilibrium data support the presence of at least two symmetric drug binding sites on ABCG2, which is distinct from the asymmetry observed for P‐gp. The data provide the first molecular details underlying the mechanism by which this transporter is capable of interacting with multiple substrates.

British Journal of Pharmacology (2006) 149, 506–515. doi:10.1038/sj.bjp.0706904