bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulation of matrix metalloproteinase activity in health and disease
Authors: Hadler‐Olsen Elin , Fadnes Bodil , Sylte Ingebrigt , Uhlin‐Hansen Lars , Winberg Jan‐Olof
Published: October 2010

The activity of matrix metalloproteinases (MMPs) is regulated at several levels, including enzyme activation, inhibition, complex formation and compartmentalization. Regulation at the transcriptional level is also important, although this is not a subject of the present minireview. Most MMPs are secreted and have their function in the extracellular environment. This is also the case for the membrane‐type MMPs (MT‐MMPs). MMPs are also found inside cells, both in the nucleus, cytosol and organelles. The role of intracellular located MMPs is still poorly understood, although recent studies have unraveled some of their functions. The localization, activation and activity of MMPs are regulated by their interactions with other proteins, proteoglycan core proteins and/or their glycosaminoglycan chains, as well as other molecules. Complexes formed between MMPs and various molecules may also include interactions with noncatalytic sites. Such exosites are regions involved in substrate processing, localized outside the active site, and are potential binding sites of specific MMP inhibitors. Knowledge about regulation of MMP activity is essential for understanding various physiological processes and pathogenesis of diseases, as well as for the development of new MMP targeting drugs.
GRAIL: a unique mediator of CD4 T‐lymphocyte unresponsiveness
Authors: Whiting Chan C. , Su Leon L. , Lin Jack T. , Garrison Fathman C.
Published: October 2010

GRAIL (gene related to anergy in lymphocytes, also known as RNF128), an ubiquitin–protein ligase (E3), utilizes a unique single transmembrane protein with a split‐function motif, and is an important gatekeeper of T‐cell unresponsiveness. Although it may play a role in other CD4 T‐cell functions including activation, survival and differentiation, GRAIL is most well characterized as a negative regulator of T‐cell receptor responsiveness and cytokine production. Here, we review the recent literature on this remarkable E3 in the regulation of human and mouse CD4 T‐cell unresponsiveness.
Trafficking and proteolytic processing of RNF13, a model PA‐TM‐RING family endosomal membrane ubiquitin ligase
Authors: Bocock Jeffrey P. , Carmicle Stephanie , Sircar Mayukh , Erickson Ann H.
Published: October 2010

RING finger protein 13 (RNF13) is a ubiquitously expressed, highly regulated ubiquitin ligase anchored in endosome membranes. A RING domain located in the cytoplasmic half of this type 1 membrane protein mediates ubiquitination in vitro but physiological substrates have not yet been identified. The protein localized in endosomal membranes undergoes extensive proteolysis in a proteasome‐dependent manner, but the mRNA level can be increased and the encoded protein stabilized under specific physiological conditions. The cytoplasmic half of RNF13 is released from the membrane by regulatory proteases and therefore has the potential to mediate ubiquitination at distant sites independent of the full‐length protein. In response to protein kinase C activation, the full‐length protein is stabilized and moves to recycling endosomes and to the inner nuclear membrane, which exposes the RING domain to the nucleoplasm. Thus RNF13 is a ubiquitin ligase that can potentially mediate ubiquitination in endosomes, on the plasma membrane, in the cytoplasm, in the nucleoplasm or on the inner nuclear membrane, with the site(s) regulated by signaling events that modulate protein targeting and proteolysis.
Factors associated with the intention to leave among newly graduated nurses in advanced‐treatment hospitals in Japan
Authors: TOMINAGA Maki T. , MIKI Akiko
Published: October 2010

Aim:  The early resignation of newly graduated nurses (NGNs) will become a concern in Japan as the need for nurses increases. The aim of this study was to conduct an investigation using the Effort–Reward Imbalance (ERI) questionnaire to examine the effect of stressful experiences in the work environment and over‐commitment on NGNs' intention to leave and to identify the factors that were associated with their intention to leave, clarifying the appropriate times at which to conduct interventions to prevent NGNs from leaving advanced‐treatment hospitals.

Methods:  Anonymous self‐administered questionnaires were distributed to all the NGNs (n = 1364) in 14 advanced‐treatment university hospitals. Questionnaires with no missing data were returned by 737 NGNs (54%). For the development of the questionnaire, we designed a framework that consisted of the factors that occur during three stages of the NGNs' transition into the workplace. The questions addressed items for individual attributes, employment and organizational characteristics, the Role Model Scale, the ERI questionnaire, two scale items for health status, and the intention to leave. In order to determine the factors that related to the dependent variables, hierarchical multiple linear regression analyses were carried out.

Results:  We revealed that effort, subjective health status, role models, and effort were important factors that related to the NGNs' intention to leave, as well as their age and city size. Over‐commitment and reward were not significant factors. We also found that three subscales of the Job Readiness Scale independently related to the NGNs' intention to leave.

Conclusion:  These findings can help employers, supervisors, and senior staff of advanced‐treatment university hospitals in Japan to improve their work environment in order to benefit NGNs and aid in their retention.
Effects of mental workload on nurses' visual behaviors during infusion pump operation
Authors: KATAOKA Jun , SASAKI Minako , KANDA Katsuya
Published: October 2010

Aim:  According to a national report on incident analysis, the mental workload that exists during the i.v. medication administration process might affect nurses' visual behavior and, thus, influence the accuracy of the process. This study examined changes in the visual behavior of nurses who operated an infusion pump under the influence of time pressure and dual tasking.

Methods:  Ten nursing students, 13 experienced nurses, and nine inexperienced nurses, equipped with an eye tracker and instruments that measure the heart rate and breathing frequency, carried out an infusion pump operation in a simulated patient room under three mental workload conditions: without a mental workload, under time pressure, and while dual tasking.

Results:  Under the time pressure condition, the total visual fixation duration of the procedures was shortened. The experienced and inexperienced nurse groups could shorten the tasks in order of priority but the student group could reduce the tasks only inconsistently. Dual tasking had no influence on the total fixation duration of the procedures. However, the fixation location was influenced by the dual‐tasking condition. This condition caused dispersed attention in the student and inexperienced‐nurse groups, but not in the experienced‐nurse group.

Conclusion:  Time pressure appears to cause nurses to shorten the duration of infusion pump operation and to reduce the quantity of checking. Dual tasking appears to have no influence on the total visual fixation duration but causes dispersed attention, reducing the quality of checking.
Self‐management program for obesity control among middle‐aged women in Korea: A pilot study
Authors: LEE Chung Yul , LEE Hyeonkyeong , JEON Kyoung Mi , HONG Yoon Mi , PARK So Hyun
Published: October 2010

Aim:  The aim of this study was to determine the effectiveness of a 12 week self‐management intervention program, as compared to a structured exercise intervention, for obesity control among middle‐aged women in Korea.

Methods:  A quasi‐experimental study was conducted with 27 women in a self‐management group and 24 in a structured exercise group for 12 weeks. The self‐management group received interventions that included walking at a convenient time and place, keeping healthy dietary habits, group workshops, phone counseling, and mobile phone short message services. The structured exercise group received a structured exercise intervention, which involved three 1 h walking classes per week at the health center. Both groups received baseline assessments before starting the interventions and at 12 weeks. The data were analyzed by using two sample t‐tests, a paired t‐test, and the χ2‐test.

Results:  After 12 weeks, there were significant changes in the health behavior, amount of body fat, and blood pressure of the participants in both intervention groups, but there was no significant difference in their body composition, blood profile, or blood pressure.

Conclusion:  Both the self‐management and the structured exercise programs were effective in controlling obesity in middle‐aged obese women in Korea. However, considering the chronic nature of obesity, the self‐management program would be more beneficial, compared to the structured exercise program, as it allows people to exercise at a convenient time and place and to learn how to cope with their lifestyle barriers.
Role of internal marketing, organizational commitment, and job stress in discerning the turnover intention of Korean nurses
Authors: LEE Haejung , KIM Myoung‐Soo , YOON Jung‐A
Published: October 2010

Aim:  The purpose of this study was to examine the discriminating factors of Korean nurses' turnover intention (TI) among internal marketing (IM), organizational commitment (OC), and job stress (JS).

Methods:  Nurses (n = 185) who had worked for 1–10 years were surveyed from six general hospitals in South Korea. The data were collected by using questionnaires and were analyzed with descriptive statistics and discriminant analysis.

Results:  The participants were grouped into three groups, depending on the level of their TI: “low TI group” (n = 58), “moderate TI group” (n = 96), and “high TI group” (n = 31). One function significantly discriminated between the high TI and low TI groups. The function correctly classified 84.3% of the participants into the two groups and 75.3% were correctly classified in the cross‐validation. Organizational commitment was the most important factor. Job stress and the IM components of staffing–promotion, reward, management philosophy, working environment, and segmentation were significant discriminant factors of TI.

Conclusion:  Based on the findings of this study, we could conclude that OC, JS, and IM play important roles in the TI of nurses. Implying a career development system as an OC management strategy, an innovative promotion policy to change conservative organizational climates and a balance of effort–reward can be considered as managerial interventions to reduce nurses' TI.
Effect of plasticity in hatching on duration as a precompetent swimming larva in the nudibranch Phestilla sibogae
Authors: Strathmann Richard R. , Strathmann Megumi F. , Ruiz‐Jones Guadalupe , Hadfield Michael G.
Published: October 2010

Abstract. Plasticity in hatching can balance risks of benthic and pelagic development and thereby affect the extent of larval dispersal. Veligers of the nudibranch Phestilla sibogae hatched from their individual capsules if the encapsulated embryos were scattered from a torn gelatinous egg ribbon. Hatching occurred as early as day 4 at 23°–25°C. The early hatchlings lacked a propodium, swam, and were not yet competent to settle and metamorphose. Hatching may be induced by predation: crabs consumed egg ribbons, and a portunid crab, caught in the act of tearing an egg ribbon, scattered encapsulated embryos. Undisturbed egg masses hatched as late as 9–11 d at 23°–25°C, or as early as 8 d in a trial at 26°C. Late hatchlings had a well‐developed propodium, and 20–100% metamorphosed within a day of exposure to the inducer from the nudibranch's coral prey. A few metamorphosed nudibranchs were found within hatching egg masses. Thus, the veligers can hatch so late that many are competent to metamorphose or so early that the obligate planktonic period can last 4 or more days. An attack by a predator means the benthic habitat is dangerous for the embryos, and swimming is presumably the safer option. In the absence of disturbance, the veligers hatch when ready or nearly ready to settle.
Bond‐Based 2D Quadratic Fingerprints in QSAR Studies: Virtual and In vitro Tyrosinase Inhibitory Activity Elucidation
Authors: Casañola‐Martin Gerardo M. , Marrero‐Ponce Yovani , Khan Mahmud T. H. , Khan Sher B. , Torrens Francisco , Pérez‐Jiménez Facundo , Rescigno Antonio , Abad Concepción
Published: October 2010

In this report, we show the results of quantitative structure–activity relationship (QSAR) studies of tyrosinase inhibitory activity, by using the bond‐based quadratic indices as molecular descriptors (MDs) and linear discriminant analysis (LDA), to generate discriminant functions to predict the anti‐tyrosinase activity. The best two models [Eqs (6) and (12)] out of the total 12 QSAR models developed here show accuracies of 93.51% and 91.21%, as well as high Matthews correlation coefficients (C) of 0.86 and 0.82, respectively, in the training set. The validation external series depicts values of 90.00% and 89.44% for these best two equations (6) and (12), respectively. Afterwards, a second external prediction data are used to perform a virtual screening of compounds reported in the literature as active (tyrosinase inhibitors). In a final step, a series of lignans is analysed using the in silico‐developed models, and in vitro corroboration of the activity is carried out. An issue of great importance to remark here is that all compounds present greater inhibition values than Kojic Acid (standard tyrosinase inhibitor: IC50 = 16.67 μm). The current obtained results could be used as a framework to increase the speed, in the biosilico discovery of leads for the treatment of skin disorders.
Angiostrongylus vasoruminfection in dogs: continuing spread and developments in diagnosis and treatment
Authors: Morgan E. , Shaw S.
Published: October 2010

Disease caused byAngiostrongylus vasorumis increasingly diagnosed in dogs, as the geographic range of the parasite increases along with awareness among clinicians. Diagnosis, treatment and prevention are not always straightforward, although recent developments offer hope for improved options in future. Understanding of the epidemiology and pathogenesis remains poor. This paper provides an overview of the current state of knowledge of this parasitic disease, focussing on the most recent developments and advances.
Global Osteitis Scoring Scale and chronic rhinosinusitis: a marker of revision surgery
Authors: Georgalas C. , Videler W. , Freling N. , Fokkens W.
Published: October 2010

Clin. Otolaryngol. 2010, 35, 455–461

Objectives:  Determine the incidence and severity of osteitis in patients with chronic rhinosinusitis using a new Global Osteitis Scoring Scale.

Design:  Validation and prospective case–control study.

Setting:  Academic Tertiary Otolaryngology Department (Academic Medical Centre, Amsterdam).

Participants:  A prospective series of 102 patients undergoing a computed tomography (CT) sinuses as part of their evaluation for chronic rhinosinusitis between January and May 2008 (study group) and an age‐ and gender‐matched control group of 68 non‐rhinosinusitis patients. Seventy‐eight of the chronic rhinosinusitis patients completed the nasal subset of the RhinoSinusitis Outcome Measure (RSOM‐31) and visual analogue scales. Their CT scans were assessed for osteitis using a newly developed Global Osteitis Scoring Scale. A subsample of 35 scans were additionally scored by a second otolaryngologist and a radiologist.

Main outcome measures:  Global Osteitis Scoring Scale.

Results:  The interrater variability of Global Osteitis Scoring Scale was low (average intraclass correlation coefficient: 0.94). Forty per cent of the chronic rhinosinusitis group and none of the control group had evidence of clinically significant osteitis. In the chronic rhinosinusitis group (102 patients), the severity of osteitis was correlated with Lund–Mackay (L–M) score (P < 0.001), duration of symptoms (P < 0.01) and previous surgery (P < 0.001), rising in incidence with increasing number of previous operations. There was no association between osteitis and age, gender, smoking, co‐existing asthma, allergy or Sumpter’s triad. Additionally, there was no correlation between osteitis and symptom burden including headache, facial pain and nasal subset score of the RhinoSinusitis Outcome Measure.

Conclusion:  In patients with recalcitrant chronic rhinosinusitis who have undergone multiple surgeries in the past, the incidence of osteitis can be as high as 64%. It does not seem to be associated with more troublesome symptoms; however, it is strongly associated with previous sinus surgery, which may be a manifestation of a shared endpoint (underlying recalcitrant disease).
Noninvasive Prediction of Left Ventricular Systolic Dysfunction in Patients With Clinically Suspected Heart Failure Using Acoustic Cardiography
Authors: Kosmicki Douglas L. , Collins Sean P. , Kontos Michael C. , Zuber Michel , Kipfer Peter , Attenhofer Jost Christine , Michaels Andrew D.
Published: October 2010

The signs and symptoms of systolic heart failure are frequently insensitive and nonspecific, making an accurate bedside diagnosis of left ventricular systolic dysfunction (LVSD) challenging. B‐type natriuretic peptide (BNP) is often used, but is not diagnostically useful when in the indeterminate range. The authors investigated the diagnostic test characteristics of acoustic cardiographic parameters to identify patients with LVSD. Four hundred thirty‐three patients with contemporaneous measurements of computerized acoustic cardiography, BNP, and echocardiography were included. The acoustic cardiographic model outperformed BNP alone at detecting reduced left ventricular ejection fraction (C statistic, 0.88 vs 0.67; P<.0001). The acoustic model with BNP did not perform better than the acoustic model alone (P=.14). Within the indeterminate BNP range, the acoustic model outperformed BNP (C statistic, 0.89 vs 0.64; P<.0001). Noninvasive computerized acoustic cardiography predicted LVSD in a diverse population. This acoustic cardiographic model outperformed BNP alone for predicting LVSD. Congest Heart Fail. 2010;16:249–253. © 2010 Wiley Periodicals, Inc.
Differentiating Pulmonary Arterial and Pulmonary Venous Hypertension and the Implications for Therapy
Authors: Dadfarmay Sina , Berkowitz Robert , Kim Bernard , Manchikalapudi Rama Bindu
Published: October 2010

Pulmonary arterial and pulmonary venous hypertension develop from distinctly different etiologies. Pulmonary arterial hypertension (PAH), or Group 1 pulmonary hypertension (PH), is a precapillary PH that arises idiopathically or as the result of a divergent array of causes, including connective tissue disease. Pulmonary venous hypertension (PVH), or Group 2 PH, primarily manifests as a postcapillary PH in the setting of left heart failure or valvular disease. A subset of PVH patients, however, develop a reactive precapillary component of PH that mimics PAH. These patients can be misdiagnosed as having Group 1 PH by 2‐dimensional echocardiography and are sometimes treated as such, which leads to exacerbation of heart failure. Therefore, 2‐dimensional or Doppler echocardiography alone cannot be used to differentiate between these two classifications of PH. This highlights the need for right heart catheterization in the clinical assessment and diagnostic work‐up of PH. The combination of imaging and invasive hemodynamic assessment by right heart catheterization provides the best diagnostic approach to ensure proper delineation of pulmonary arterial and pulmonary venous hypertension, and in turn leads to appropriate treatment. Congest Heart Fail. 2010;16:287–291. © 2010 Wiley Periodicals, Inc.
Monitoring of pathogenic and non‐pathogenic Fusarium oxysporum strains during tomato plant infection
Authors: Validov Shamil Z. , Kamilova Faina D. , Lugtenberg Ben J. J.
Published: October 2010

Monitoring of pathogenic strains of Fusarium oxysporum (Fox), which cause wilt and rots on agricultural and ornamental plants, is important for predicting disease outbreaks. Since both pathogenic and non‐pathogenic strains of Fox are ubiquitous and are able to colonize plant roots, detection of Fox DNA in plant material is not the ultimate proof of an ongoing infection which would cause damage to the plant. We followed the colonization of tomato plants by strains Fox f. sp. radicis‐lycopersici ZUM2407 (a tomato foot and root rot pathogen), Fox f. sp. radicis‐cucumerinum V03‐2g (a cucumber root rot pathogen) and Fox Fo47 (a well‐known non‐pathogenic biocontrol strain). We determined fungal DNA concentrations in tomato plantlets by quantitative PCR (qPCR) with primers complementary to the intergenic spacer region (IGS) of these three Fox strains. Two weeks after inoculation of tomato seedlings with these Fox strains, the DNA concentration of Forl ZUM2407 was five times higher than that of the non‐compatible pathogen Forc V03‐2g and 10 times higher than that of Fo47. In 3‐week‐old plantlets the concentration of Forl ZUM2407 DNA was at least 10 times higher than those of the other strains. The fungal DNA concentration, as determined by qPCR, appeared to be in good agreement with data of the score of visible symptoms of tomato foot and root rot obtained 3 weeks after inoculation of tomato with Forl ZUM2407. Our results show that targeting of the multicopy ribosomal operon results in a highly sensitive qPCR reaction for the detection of Fox DNA. Since formae speciales of Fox cannot be distinguished by comparison of ribosomal operons, detection of Fox DNA is not evidence of plant infection by a compatible pathogen. Nevertheless, the observed difference in levels of plant colonization between pathogenic and non‐pathogenic strains strongly suggests that a concentration of Fox DNA in plant material above the threshold level of 0.005% is due to proliferation of pathogenic Fox.
Comparative genomics of Lactobacillus
Authors: Kant Ravi , Blom Jochen , Palva Airi , Siezen Roland J. , de Vos Willem M.
Published: October 2010

The genus Lactobacillus includes a diverse group of bacteria consisting of many species that are associated with fermentations of plants, meat or milk. In addition, various lactobacilli are natural inhabitants of the intestinal tract of humans and other animals. Finally, several Lactobacillus strains are marketed as probiotics as their consumption can confer a health benefit to host. Presently, 154 Lactobacillus species are known and a growing fraction of these are subject to draft genome sequencing. However, complete genome sequences are needed to provide a platform for detailed genomic comparisons. Therefore, we selected a total of 20 genomes of various Lactobacillus strains for which complete genomic sequences have been reported. These genomes had sizes varying from 1.8 to 3.3 Mb and other characteristic features, such as G+C content that ranged from 33% to 51%. The Lactobacillus pan genome was found to consist of approximately 14 000 protein‐encoding genes while all 20 genomes shared a total of 383 sets of orthologous genes that defined the Lactobacillus core genome (LCG). Based on advanced phylogeny of the proteins encoded by this LCG, we grouped the 20 strains into three main groups and defined core group genes present in all genomes of a single group, signature group genes shared in all genomes of one group but absent in all other Lactobacillus genomes, and Group‐specific ORFans present in core group genes of one group and absent in all other complete genomes. The latter are of specific value in defining the different groups of genomes. The study provides a platform for present individual comparisons as well as future analysis of new Lactobacillus genomes.
Packaging Protest: Media Coverage of Indigenous People's Collective Action
Authors: WILKES RIMA , CORRIGALL‐BROWN CATHERINE , MYERS DANIEL J.
Published: October 2010

Les personnes autochtones au Canada se sont lancées dans des centaines d'actions collectives. Utilisant la littérature sur les nouvelles et sur les événements collectifs, nous examinons d'une façon systématique les facteurs associés avec le nombre d'articles, leur placement sur la premiére page, et l'inclusion de photos. Nous trouvons que l'augmentation de la taille ou de la longueur d'un événement n'améliore pas sa couverture. Quand il s'agit de celle‐ci, c'est uniquement la forme de l'événement qui compte. Certes, l'escalade de tactique accroít la quantité de couverture, mais c'est seulement les tactiques perturbatrices qui augmentent la couverture premiére page. Par contraste, ce sont principalement les routines de nouvelles du média et pas par les tactiques de la part des activistes qui déterminent l'inclusion d'une photo.
Socioeconomic Status and Body Mass Index in Canada: Exploring Measures and Mechanisms
Authors: GODLEY JENNY , McLAREN LINDSAY
Published: October 2010

Nous examinons la relation entre le statut socio‐économique (SES), les caractéristiques socio‐économiques (SES), le style de vie (consommation de fruits et légumes, exercice physique, usage du tabac, et consommation d'alcool) et l'indice de masse corporelle (IMC) sur la base des données de l'Enquête sur la santé dans les collectivités canadiennes 2.1. Nous explorons deux différentes mesures socio‐économiques, éducation et revenu, afin d'élucider les explications matérielles et culturelles de la relation SES‐IMC. Les résultats varient de manière significative entre les genres, dégageant la complexité de la relation entre SES, les facteurs socio‐démographiques et de style de vie, et l'IMC. Nous suggérons que la masse corporelle demeure un symbole de statut qui diffère entre les genres, et que les facteurs culturaux et psycho‐sociaux sont peut‐être plus importants que les facteurs matériaux en perpétuant cette inégalité dans le domaine de la santé.
The Promise of a Sociology Degree in Canadian Higher Education
Authors: PUDDEPHATT ANTONY , NELSEN RANDLE W.
Published: October 2010

Des descriptions de programmes universitaires de cinquante‐quatre départements de sociologie anglophones ont été examinées afin de découvrir les thèmes publicitaires dirigés aux étudiants éventuels. En comparant les départements des universités comprenant des programmes de doctorat aux universités offrant principalement des programmes de baccalauréat, on a trouvé des variations dans leurs messages et leurs promesses aux étudiants. On a remarqué des formules habituelles dans les promesses de leur programme (l'étude des arts libéraux, le choix de carrière, ou l'amélioration des conditions sociales), l'acquisition des habilités (les pensées critiques ou déterminées par le marché) et les expériences d'apprentissage prévues (l'éducation élitiste, l'environnement d'apprentissage accessible, ou la stimulation intellectuelle). Après avoir composé un rapport portant sur ces modèles, nous prenons en considération leurs conséquences dans le contexte des questions plus générales de l'éducation universitaire.
A simple method for in situ‐labelling with 15N and 13C of grassland plant species by foliar brushing
Authors: Putz Birgit , Drapela Thomas , Wanek Wolfgang , Schmidt Olaf , Frank Thomas , Zaller Johann G.
Published: October 2010

1. Labelling plants with 15N and 13C stable isotopes usually require cultivation of plants in isotopically enriched soil and gas‐tight labelling chambers ‐ both approaches are not suitable if one aims to investigate in situ species interactions in real plant communities.

2. In this greenhouse experiment, we tested a labelling method in which dual‐labelled (15N, 13C) urea solution is brushed directly onto leaves of twelve temperate grassland species representing grasses, non‐leguminous forbs and legumes.

3. Across all plant species, shoots (15N: 0·145; 13C: 0·090 atom percent excess, APE) and roots (15N: 0·051; 13C: 0·023 APE) were significantly enriched after five daily labelling events. Generally, isotopic enrichments were significantly higher in shoots than in roots. No clear pattern of absolute isotopic enrichment was observed between plant functional groups; however, grasses showed a more even allocation between shoots and roots than forbs and legumes. Isotopic enrichment levels after 4 weeks were lower, higher or unchanged compared to those of week one and varied between species or plant parts.

4. Considering the consistent enrichment levels and simplicity of this method, we conclude that it can be applied widely in ecological studies of above‐belowground plant–plant or plant–animal interactions even in real plant communities.
Theta Method Dynamics
Authors: Barclay Graeme J. , Griffiths David F. , Higham Desmond J.
Published: October 2010

Long-term solutions of the theta method applied to scalar nonlinear differential equations are studied in this paper. In the case where the equation has a stable steady state, lower bounds on the basin of non-oscillatory, monotonic attraction for the theta method are derived. Spurious period two solutions are then analysed. Under mild assumptions, precise results are obtained concerning the generic nature and stability of these solutions for small timesteps. Particular problem classes are studied, and direct connections are made between the existence and stability of period two solutions and the dynamics of the theta method. The analysis is extended to a wide class of semi-discretized partial differential equations. Numerical examples are given.
Counting Unlabelled Subtrees of a Tree is #P-complete
Authors: Goldberg Leslie Ann , Jerrum Mark
Published: October 2010

The problem of counting unlabelled subtrees of a tree (that is, sub-trees that are distinct up to isomorphism) is #P-complete, and hence equivalent in computational difficulty to evaluating the permanent of a 0,1-matrix.
Primes in Sequences Associated to Polynomials (After Lehmer)
Authors: Einsiedler Manfred , Everest Graham , Ward Thomas
Published: October 2010

In a paper of 1933, D. H. Lehmer continued Pierce's study of integral sequences associated to polynomials generalizing the Mersenne sequence. He developed divisibility criteria, and suggested that prime apparition in these sequences — or in closely related sequences — would be denser if the polynomials were close to cyclotomic, using a natural measure of closeness.

We review briefly some of the main developments since Lehmer's paper, and report on further computational work on these sequences. In particular, we use Mossinghoff's collection of polynomials with smallest known measure to assemble evidence for the distribution of primes in these sequences predicted by standard heuristic arguments.

The calculations lend weight to standard conjectures about Mersenne primes, and the use of polynomials with small measure permits much larger numbers of primes to be generated than in the Mersenne case.
A Constructive Analysis of a Proof that the Numerical Range is Convex
Authors: Bridges Douglas , Havea Robin
Published: October 2010

It is shown where the classical proof of the convexity of the numerical range of an operator on a Hilbert space breaks down by using principles that are not valid in intuitionistic logic. Those breakdowns are then repaired, as far as possible, to provide constructive versions of the convexity theorem. Finally, it is shown that our results are the best possible in a constructive setting.
Computational Aspects of Classifying Singularities
Authors: Kirk N. P.
Published: October 2010

A Maple package which performs the symbolic algebra central to problems in local singularity theory is described. This is a generalisation of previous projects, which dealt only with problems in elementary catastrophe theory. Applications to specific problems are described, and a survey given of the powerful techniques from singularity theory that are used by the package. A description of the underlying algorithm is given, and some of the more important computational aspects discussed. The package, user manual and installation instructions are available in the appendices to this article.
Explicit Bounds for Hermite Polynomials in the Oscillatory Region
Authors: Foster William H. , Krasikov Ilia
Published: October 2010

We apply a method of positive quadratic forms based on polynomial inequalities to establish sharp explicit bounds on the envelope of Hermite polynomials in the oscillatory region |x| < (2k – 3/2)1/2.
Rotational and Quasiviscous Cold Flow Models for Axisymmetric Hybrid Propellant Chambers
Authors: Majdalani Joseph , Akiki Michel
Published: October 2010

In this work, we present two simple mean flow solutions that mimic the bulk gas motion inside a full-length, cylindrical hybrid rocket engine. Two distinct methods are used. The first is based on steady, axisymmetric, rotational, and incompressible flow conditions. It leads to an Eulerian solution that observes the normal sidewall mass injection condition while assuming a sinusoidal injection profile at the head end wall. The second approach constitutes a slight improvement over the first in its inclusion of viscous effects. At the outset, a first order viscous approximation is constructed using regular perturbations in the reciprocal of the wall injection Reynolds number. The asymptotic approximation is derived from a general similarity reduced Navier–Stokes equation for a viscous tube with regressing porous walls. It is then compared and shown to agree remarkably well with two existing solutions. The resulting formulations enable us to model the streamtubes observed in conventional hybrid engines in which the parallel motion of gaseous oxidizer is coupled with the cross-streamwise (i.e., sidewall) addition of solid fuel. Furthermore, estimates for pressure, velocity, and vorticity distributions in the simulated engine are provided in closed form. Our idealized hybrid engine is modeled as a porous circular-port chamber with head end injection. The mathematical treatment is based on a standard similarity approach that is tailored to permit sinusoidal injection at the head end.
Numerical Prediction of Impact Force in Cavitating Flows
Authors: Wang Hong , Zhu Baoshan
Published: October 2010

A numerical method including a macroscopic cavitation model based on the homogeneous flow theory and a microscopic cavitation model based on the bubble dynamics is proposed for the prediction of the impact force caused by cavitation bubble collapse in cavitating flows. A large eddy simulation solver, which is incorporated with a macroscopic cavitation model, is applied to simulate the unsteady cavitating flows. Based on the simulated flow field, the evolution of the cavitation bubbles is determined by a microscopic cavitation model from the resolution of a Rayleigh–Plesset equation including the effects of the surface tension, the viscosity and compressibility of fluid, the thermal conduction and radiation, the phase transition of water vapor at the interface, and the chemical reactions. The cavitation flow around a hydrofoil is simulated to validate the macroscopic cavitation model. A good quantitative agreement is obtained between the prediction and the experiment. The proposed numerical method is applied to predict the impact force at cavitation bubble collapse on a KT section in cavitating flows. It is found that the shock pressure caused by cavitation bubble collapse is very high. The impact force is predicted qualitatively compared with the experimental data.
Unsteady Peristaltic Pumping in a Finite Length Tube With Permeable Wall
Authors: Ravi Kumar Y. V. K. , Krishna Kumari.P S. V. H. N. , Ramana Murthy M. V. , Sreenadh S.
Published: October 2010

Peristaltic transport due to a sinusoidal wave traveling on the boundary of a tube filled with an incompressible fluid is presented. Solution is obtained under infinite wavelength and zero Reynolds number in a finite length tube which extends the study of Li and Brasseur (1993, “Non-Steady Peristaltic Transport in Finite-Length Tubes,” J. Fluid Mech., 248, pp. 129–151). Boundary conditions are changed to include wall permeability. Analysis of pressure profile is described.
Viscous Disk Air Flow Displacement Device (VDAFDD): Development and Performance
Authors: Hilton Jonathan M. , Ligrani Phillip M.
Published: October 2010

The development and performance of a unique viscous disk air flow displacement device (or VDAFDD) for inducing airflow in confined spaces is described. The development is motivated by electronic cooling, where limitations on space are especially severe and the need exists to circulate air over or through the key components using a compact and efficient device. To induce air motion, array of disks are employed with their axis of rotation perpendicular to the air stream. Results from the most successful prototype, which was developed and tested, prototype 2, are presented for Reynolds numbers up to 671 to illustrate nominal behavior, as well as behavior as a number of different parameters are altered, including the magnitude of exit flow restriction, the air gap above the disks, and the number of disks employed to induce air motion. Also discussed are the effects of disk rotational speed, comparisons with theoretical predictions, and one earlier prototype whose performance is significantly less than that of prototype 2.
Integral Force/Moment Waterjet Model for CFD Simulations
Authors: Kandasamy Manivannan , Ooi Seng Keat , Carrica Pablo , Stern Frederick
Published: October 2010

An integral force/moment waterjet model for computational fluid dynamics (CFD) is derived for ship local flow/powering predictions, including sinkage and trim. The waterjet induced reaction forces and moment and waterjet/hull interaction stern force replicate the effects of the waterjet without requiring detailed simulations of the waterjet system. The model extends the International Towing Tank Conference (ITTC) waterjet model for sinkage and trim by using an alternative control volume also appropriate for CFD and by including vertical forces and pitching moment in the waterjet/hull force/moment balance. The same grid is used for both without and with waterjet simulations. The CFD waterjet model requires limited waterjet geometry (inlet and outlet areas and locations, and weight of working fluid) and several waterjet flow (mass flow rate, inlet pressure force, inlet and outlet momentum correction factors and flow angles, and stern force and location) input variables. The CFD waterjet model can be used for local flow predictions by using waterjet flow input variables provided by ITTC waterjet model test data, including additional data for waterjet induced inlet pressure and stern forces. It can also be used for powering predictions once waterjet flow input variable correlations are available based on CFD for the waterjet system and/or experimental data. The CFD waterjet model is demonstrated for local flow predictions for the DTMB 5594 high-speed sealift ship model for which ITTC waterjet model test data, including additional data for waterjet induced stern forces, are available. Correlations for the waterjet flow input variables are shown to be feasible using a combination of CFD and experimental data for the waterjet system for three different hulls.
Numerical and Experimental Study on Jet Trajectories and Mixing Behavior of Venturi-Jet Mixer
Authors: Sundararaj S. , Selladurai V.
Published: October 2010

An investigation of the jet trajectories and mixing behavior of venturi-jet mixers, in which turbulent jet injects fluid at an arbitrary angle to mix incompressible fluids, is described in this paper. Numerical results of an incompressible cross flow-jet mixing in venturi-jet mixers are presented and validated against experimental results. Jet trajectories, concentration decay of tracer jet, spatial unmixedness, and mixing length are computed for a range of injection angles (45 deg≤θo≤135 deg). Twenty-five cases are studied with five different initial injection angles, each with five different jet momentum ratios. As an example of practical insights that can be gained from such detailed analysis, the resulting flow field is used to obtain an equation for trajectory and tracer concentration in the mixer. The penetration of jet scales with the third root of the jet-to-mainstream momentum ratio and that of with square root of downstream distance. The decay of mean concentration scales with the inverse of axial distance and with the negative root of injection angle. The results show a consistency in the experimental data and simulation has provided a good insight into the flow details and has paved the way in optimization of the geometry based on jet injection angle to get a good mixing efficiency.
Stokes Flow Through a Periodically Grooved Tube
Authors: Ng Chiu-On , Wang C. Y.
Published: October 2010

This is an analytical study on Stokes flow through a tube of which the wall is patterned with periodic transverse grooves filled with an inviscid gas. In one period of the pattern, the fluid flows through an annular groove and an annular rib subject to no-shear and no-slip boundary conditions, respectively. The fluid may penetrate the groove to a certain depth, so there is an abrupt change in the cross section of flow through the two regions. The problem is solved by the method of domain decomposition and eigenfunction expansions, where the coefficients of the expansion series are determined by matching velocities, stress, and pressure on the domain interface. The effective slip length and pressure distributions are examined as functions of the geometrical parameters (tube radius, depth of fluid penetration into grooves, and no-shear area fraction of the wall). Particular attention is paid to the limiting case of flow through annular fins on a no-shear wall. Results are generated for the streamlines, resistance, and pressure drop due to the fins. It is found that the wall condition, whether no-shear or no-slip, will be immaterial when the fin interval is smaller than a certain threshold depending on the orifice ratio.
LRO-LAMP Observations of the LCROSS Impact Plume
Authors: Gladstone G. Randall , Hurley Dana M. , Retherford Kurt D. , Feldman Paul D. , Pryor Wayne R. , Chaufray Jean-Yves , Versteeg Maarten , Greathouse Thomas K. , Steffl Andrew J. , Throop Henry , Parker Joel Wm. , Kaufmann David E. , Egan Anthony F. , Davis Michael W. , Slater David C. , Mukherjee Joey , Miles Paul F. , Hendrix Amanda R. , Colaprete Anthony , Stern S. Alan
Published: October 2010

Watering the Moon

About a year ago, a spent upper stage of an Atlas rocket was deliberately crashed into a crater at the south pole of the Moon, ejecting a plume of debris, dust, and vapor. The goal of this event, the Lunar Crater Observation and Sensing Satellite (LCROSS) experiment, was to search for water and other volatiles in the soil of one of the coldest places on the Moon: the permanently shadowed region within the Cabeus crater. Using ultraviolet, visible, and near-infrared spectroscopy data from accompanying craft,

Colaprete
et al.

(p.
463
; see the news story by

Kerr

; see the cover) found evidence for the presence of water and other volatiles within the ejecta cloud.

Schultz
et al.

(p.
468
) monitored the different stages of the impact and the resulting plume.

Gladstone
et al.

(p.
472
), using an ultraviolet spectrograph onboard the Lunar Reconnaissance Orbiter (LRO), detected H
2
, CO, Ca, Hg, and Mg in the impact plume, and

Hayne
et al.

(p.
477
) measured the thermal signature of the impact and discovered that it had heated a 30 to 200 square-meter region from ∼40 kelvin to at least 950 kelvin.

Paige
et al.

(p. 479) mapped cryogenic zones predictive of volatile entrapment, and

Mitrofanov
et al.

(p.
483
) used LRO instruments to confirm that surface temperatures in the south polar region persist even in sunlight. In all, about 155 kilograms of water vapor was emitted during the impact; meanwhile, the LRO continues to orbit the Moon, sending back a stream of data to help us understand the evolution of its complex surface structures.
Diviner Lunar Radiometer Observations of Cold Traps in the Moon’s South Polar Region
Authors: Paige David A. , Siegler Matthew A. , Zhang Jo Ann , Hayne Paul O. , Foote Emily J. , Bennett Kristen A. , Vasavada Ashwin R. , Greenhagen Benjamin T. , Schofield John T. , McCleese Daniel J. , Foote Marc C. , DeJong Eric , Bills Bruce G. , Hartford Wayne , Murray Bruce C. , Allen Carlton C. , Snook Kelly , Soderblom Laurence A. , Calcutt Simon , Taylor Fredric W. , Bowles Neil E. , Bandfield Joshua L. , Elphic Richard , Ghent Rebecca , Glotch Timothy D. , Wyatt Michael B. , Lucey Paul G.
Published: October 2010

Watering the Moon

About a year ago, a spent upper stage of an Atlas rocket was deliberately crashed into a crater at the south pole of the Moon, ejecting a plume of debris, dust, and vapor. The goal of this event, the Lunar Crater Observation and Sensing Satellite (LCROSS) experiment, was to search for water and other volatiles in the soil of one of the coldest places on the Moon: the permanently shadowed region within the Cabeus crater. Using ultraviolet, visible, and near-infrared spectroscopy data from accompanying craft,

Colaprete
et al.

(p.
463
; see the news story by

Kerr

; see the cover) found evidence for the presence of water and other volatiles within the ejecta cloud.

Schultz
et al.

(p.
468
) monitored the different stages of the impact and the resulting plume.

Gladstone
et al.

(p.
472
), using an ultraviolet spectrograph onboard the Lunar Reconnaissance Orbiter (LRO), detected H
2
, CO, Ca, Hg, and Mg in the impact plume, and

Hayne
et al.

(p.
477
) measured the thermal signature of the impact and discovered that it had heated a 30 to 200 square-meter region from ∼40 kelvin to at least 950 kelvin.

Paige
et al.

(p. 479) mapped cryogenic zones predictive of volatile entrapment, and

Mitrofanov
et al.

(p.
483
) used LRO instruments to confirm that surface temperatures in the south polar region persist even in sunlight. In all, about 155 kilograms of water vapor was emitted during the impact; meanwhile, the LRO continues to orbit the Moon, sending back a stream of data to help us understand the evolution of its complex surface structures.
Mechanisms of Proton Conduction and Gating in Influenza M2 Proton Channels from Solid-State NMR
Authors: Hu Fanghao , Luo Wenbin , Hong Mei
Published: October 2010

M2 Out of the Envelope

The M2 protein from influenza A virus forms an acid-activated tetrameric proton channel in the viral envelope and is essential for viral replication. Two manuscripts shed light on the functional mechanism of this channel.

Sharma
et al.

(p.
509
; see the Perspective by

Fiorin
et al.

) determined the structure of the conductance domain in a lipid bilayer and propose that a histidine and tryptophan from each monomer form a cluster that guides protons through the channel in a mechanism that involves forming and breaking hydrogen bonds between adjacent pairs of histidines.

Hu
et al.

(p.
505
; see the Perspective by

Fiorin
et al.

) focused on the structure and dynamics of the proton-selective histidine at high and low pH, proposing that proton conduction involves histidine deprotonation and reprotonation.
Insight into the Mechanism of the Influenza A Proton Channel from a Structure in a Lipid Bilayer
Authors: Sharma Mukesh , Yi Myunggi , Dong Hao , Qin Huajun , Peterson Emily , Busath David D. , Zhou Huan-Xiang , Cross Timothy A.
Published: October 2010

M2 Out of the Envelope

The M2 protein from influenza A virus forms an acid-activated tetrameric proton channel in the viral envelope and is essential for viral replication. Two manuscripts shed light on the functional mechanism of this channel.

Sharma
et al.

(p.
509
; see the Perspective by

Fiorin
et al.

) determined the structure of the conductance domain in a lipid bilayer and propose that a histidine and tryptophan from each monomer form a cluster that guides protons through the channel in a mechanism that involves forming and breaking hydrogen bonds between adjacent pairs of histidines.

Hu
et al.

(p.
505
; see the Perspective by

Fiorin
et al.

) focused on the structure and dynamics of the proton-selective histidine at high and low pH, proposing that proton conduction involves histidine deprotonation and reprotonation.