bluuebunny/crossref_metadata_2025 huggingface dataset:
Angiotensin‐converting enzyme 2 antagonizes angiotensin II‐induced pressor response and NADPH oxidase activation in Wistar–Kyoto rats and spontaneously hypertensive rats
Authors: Lo Jennifer , Patel Vaibhav B. , Wang Zuocheng , Levasseur Jody , Kaufman Susan , Penninger Josef M. , Oudit Gavin Y.
Published: July 2012

New Findings

What is the central question of this study?

Angiotensin‐converting enzyme 2 (ACE2), an enzyme which converts angiotensin II (Ang II) into angiotensin‐(1–7) [Ang‐(1–7)] and terminates the effects of Ang II, is a negative regulator of activated renin‐angiotensin system (RAS). Cardiac overexpression of ACE2 has shown conflicting results on myocardial fibrosis in contrast to marked anti‐ hypertensive and anti‐remodelling properties.

What is the main finding and its importance?

Recombinant hACE2 administration attenuates oxidative stress, NADPH oxidase activity and ERK1/2 signalling and high blood pressure confirming its beneficial role in two rat models of hypertension.

Angiotensin‐converting enzyme 2 (ACE2), a monocarboxypeptidase capable of metabolizing angiotensin II (Ang II) into angiotensin‐(1–7) [Ang‐(1–7)], has emerged as a potential therapeutic target. We hypothesized that ACE2 is a negative regulator of Ang II‐mediated pathological effects in vivo. In Wistar–Kyoto (WKY) rats, Ang II infusion (0.1 μg min−1 kg−1) induced a pressor response, activation of NADPH oxidase and generation of superoxide in the heart, kidney and blood vessels; these effects were significantly blunted by recombinant human ACE2 (rhACE2; 2 mg kg−1), in association with a lowering of plasma Ang II and elevation of Ang‐(1–7) levels. In the spontaneously hypertensive rat (SHR) model, rhACE2 (2 mg kg−1 day−1) delivered over a 14 day period partly corrected the hypertension, the NADPH oxidase activation and the increased superoxide generation in the heart, kidney and blood vessels. Treatment with rhACE2 inhibited Ang II‐mediated phosphorylation of the myocardial extracellular signal‐regulated kinase 1/2 pathway in WKY rats, with congruent results seen in SHR hearts. Hence, rhACE2 is an important negative regulator of the Ang II‐induced pressor response and NADPH oxidase activation and suppresses pathological myocardial signalling, thereby providing a novel therapeutic agent with which to antagonize an activated renin–angiotesin system.
Nucleus of the solitary tract catecholaminergic neurons modulate the cardiovascular response to psychological stress in rats
Authors: Daubert Daisy L. , McCowan Michael , Erdos Benedek , Scheuer Deborah A.
Published: July 2012

Key points

Exaggerated cardiovascular responses to stress increase risk for hypertension and cardiovascular disease, but the mechanisms controlling the magnitude of this response are not understood.

Catecholaminergic neurons located in the hindbrain area termed the nucleus of the solitary tract (NTS) modulate the control of blood pressure and are activated by psychological stress, but their role in modulating the cardiovascular response to stress is unknown.

In this study we lesioned these NTS catecholaminergic neurons and measured the cardiovascular and hormonal responses to psychological stress in rats.

We showed that lesioning these neurons increases baseline blood pressure and causes an exaggerated blood pressure response to acute or repeated psychological stress, suggesting that physiological or pathophysiological inhibition of these neurons could lead to exaggerated stress responses and hypertension.

These results help us understand the mechanisms that contribute to enhanced cardiovascular responses to psychological stress.

Abstract  Catecholaminergic neurons within the central nervous system are an integral part of stress‐related neurocircuitry, and the nucleus of the solitary tract (NTS) plays a critical role in cardiovascular regulation. We tested the hypothesis that NTS catecholaminergic neurons attenuate psychological stress‐induced increases in blood pressure and promote neuroendocrine activation in response to psychological stress. Anti‐dopamine‐β‐hydroxylase antibody conjugated to the neurotoxin saporin (DSAP) or saline vehicle was microinjected into the NTS to lesion catecholaminergic neurons in male Sprague–Dawley rats, and 17 days later the rats were subjected to 60 min of restraint stress for five consecutive days. DSAP treatment significantly enhanced the integrated increase in mean arterial pressure during restraint on the first (800 ± 128 and 1115 ± 116 mmHg (min) for saline‐ and DSAP‐treated rats) and fifth days (655 ± 116 and 1035 ± 113 mmHg (min) for saline‐ and DSAP‐treated rats; P < 0.01 for overall effect of DSAP treatment) of restraint. In contrast, after 60 min of restraint plasma corticosterone concentration was significantly lower in DSAP‐treated compared with saline‐treated rats (25.9 ± 7 compared with 46.8 ± 7 μg dl−1 for DSAP‐ and saline‐treated rats; P < 0.05). DSAP treatment also significantly reduced baseline plasma adrenaline concentration (403 ± 69 compared with 73 ± 29 pg ml−1 for saline‐ and DSAP‐treated rats), but did not alter the magnitude of the adrenaline response to restraint. The data suggest that NTS catecholaminergic neurons normally inhibit the arterial pressure response, but help maintain the corticosterone response to restraint stress.
New Targets for Acetylation in Autophagy
Authors: Hamaï Ahmed , Codogno Patrice
Published: July 2012

Yeast and mammals use protein acetylation to promote the formation of the autophagosome.
Two for One in Iron Homeostasis
Authors: Gough Nancy R.
Published: July 2012

The
Chlamydia
protein YtgCR is cleaved to yield a metal permease and an iron-regulated transcriptional repressor.
A Linchpin for Metabolism and Immunity
Authors: Andrianantoandro Ernesto
Published: July 2012

A metabolic regulator also modulates immune cells in fatty tissue.
In Vitro
Comparison of Nitrofurazone- and Silver Alloy-Coated Foley Catheters for Contact-Dependent and Diffusible Inhibition of Urinary Tract Infection-Associated Microorganisms
Authors: Johnson James R. , Johnston Brian , Kuskowski Michael A.
Published: July 2012

Two marketed antimicrobial-coated Foley catheters were compared for
in vitro
diffusible and contact-dependent inhibition of 11 urinary tract infection-associated microorganisms in an adherence-biofilm assay. Nitrofurazone-coated catheters significantly outperformed silver alloy-coated catheters for inhibitory activity, according to both inoculum broth and catheter sonicate counts, whether compared directly or against the corresponding control catheters. Although inhibition waned with catheter preincubation in saline, some organisms were inhibited even after a 48-h catheter preincubation, especially by the nitrofurazone-coated catheter.
Fluoxetine Is a Potent Inhibitor of Coxsackievirus Replication
Authors: Zuo Jun , Quinn Kevin K. , Kye Steve , Cooper Paige , Damoiseaux Robert , Krogstad Paul
Published: July 2012

No antiviral drugs currently exist for the treatment of enterovirus infections, which are often severe and potentially life threatening. Molecular screening of small molecule libraries identified fluoxetine, a selective serotonin reuptake inhibitor, as a potent inhibitor of coxsackievirus replication. Fluoxetine did not interfere with either viral entry or translation of the viral genome. Instead, fluoxetine and its metabolite norfluoxetine markedly reduced the synthesis of viral RNA and protein. In view of its favorable pharmacokinetics and safety profile, fluoxetine warrants additional study as a potential antiviral agent for enterovirus infections.
5S Clavam Biosynthesis Is Controlled by an Atypical Two-Component Regulatory System in Streptomyces clavuligerus
Authors: Kwong Thomas , Zelyas Nathan J. , Cai Hui , Tahlan Kapil , Wong Annie , Jensen Susan E.
Published: July 2012

Streptomyces clavuligerus
produces a collection of five clavam metabolites, including the clinically important β-lactamase inhibitor clavulanic acid, as well as four structurally related metabolites called 5S clavams. The paralogue gene cluster of
S. clavuligerus
is one of three clusters of genes for the production of these clavam metabolites. A region downstream of the cluster was analyzed, and
snk
,
res1
, and
res2
, encoding elements of an atypical two-component regulatory system, were located. Mutation of any one of the three genes had no effect on clavulanic acid production, but
snk
and
res2
mutants produced no 5S clavams, whereas
res1
mutants overproduced 5S clavams. Reverse transcriptase PCR analyses showed that transcription of
cvm7p
(which encodes a transcriptional activator of 5S clavam biosynthesis) and 5S clavam biosynthetic genes was eliminated in
snk
and in
res2
mutants but that
snk
and
res2
transcription was unaffected in a
cvm7p
mutant. Both
snk
and
res2
mutants could be complemented by introduction of
cvm7p
under the control of an independently regulated promoter.
In vitro
assays showed that Snk can autophosphorylate and transfer its phosphate group to both Res1 and Res2, and Snk-H365, Res1-D52, and Res2-D52 were identified as the phosphorylation sites for the system. Dephosphorylation assays indicated that Res1 stimulates dephosphorylation of Res2∼P. These results suggest a regulatory cascade in which Snk and Res2 form a two-component system controlling
cvm7p
transcription, with Res1 serving as a checkpoint to modulate phosphorylation levels. Cvm7P then activates transcription of 5S clavam biosynthetic genes.
Correlation between Fecal Concentrations of Ciprofloxacin and Fecal Counts of Resistant Enterobacteriaceae in Piglets Treated with Ciprofloxacin: toward New Means To Control the Spread of Resistance?
Authors: Nguyen Thu Thuy , Chachaty Elisabeth , Huy Clarisse , Cambier Carole , de Gunzburg Jean , Mentré France , Andremont Antoine
Published: July 2012

We assessed in a piglet model the relationship between fecal ciprofloxacin concentrations and ciprofloxacin-resistant
Enterobacteriaceae
counts. Twenty-nine piglets were orally treated with placebo or with 1.5 or 15 mg ciprofloxacin/kg of body weight/day from day 1 (D1) to D5. Areas under the curve (AUC) of concentrations increased sharply with dose and correlated positively with AUC of resistant bacteria log counts between D1 and D9. Removing residual colonic quinolones could help to control the emergence of resistance in fecal flora.
Investigation of Metronidazole Use during Pregnancy and Adverse Birth Outcomes
Authors: Koss Catherine A. , Baras Dana C. , Lane Sandra D. , Aubry Richard , Marcus Michele , Markowitz Lauri E. , Koumans Emilia H.
Published: July 2012

To assess whether treatment with metronidazole during pregnancy is associated with preterm birth, low birth weight, or major congenital anomalies, we conducted chart reviews and an analysis of electronic data from a cohort of women delivering at an urban New York State hospital. Of 2,829 singleton/mother pairs, 922 (32.6%) mothers were treated with metronidazole for clinical indications, 348 (12.3%) during the first trimester of pregnancy and 553 (19.5%) in the second or third trimester. There were 333 (11.8%) preterm births, 262 (9.3%) infants of low birth weight, and 52 infants (1.8%) with congenital anomalies. In multivariable analysis, no association was found between metronidazole treatment and preterm birth (odds ratio [OR], 1.02 [95% confidence interval [CI], 0.80 to 1.32]), low birth weight (OR, 1.05 [95% CI, 0.77 to 1.43]), or treatment in the first trimester and congenital anomalies (OR, 0.86 [0.30 to 2.45]). We found no association between metronidazole treatment during the first or later trimesters of pregnancy and preterm birth, low birth weight, or congenital anomalies.
Tracing Putative Trafficking of the Glycolytic Enzyme Enolase via SNARE-Driven Unconventional Secretion
Authors: Miura Natsuko , Kirino Aya , Endo Satoshi , Morisaka Hironobu , Kuroda Kouichi , Takagi Masahiro , Ueda Mitsuyoshi
Published: July 2012

Glycolytic enzymes are cytosolic proteins, but they also play important extracellular roles in cell-cell communication and infection. We used
Saccharomyces cerevisiae
to analyze the secretory pathway of some of these enzymes, including enolase, phosphoglucose isomerase, triose phosphate isomerase, and fructose 1,6-bisphosphate aldolase. Enolase, phosphoglucose isomerase, and an N-terminal 28-amino-acid-long fragment of enolase were secreted in a
sec23
-independent manner. The enhanced green fluorescent protein (EGFP)-conjugated enolase fragment formed cellular foci, some of which were found at the cell periphery. Therefore, we speculated that an overview of the secretory pathway could be gained by investigating the colocalization of the enolase fragment with intracellular proteins. The DsRed-conjugated enolase fragment colocalized with membrane proteins at the
cis
-Golgi complex, nucleus, endosome, and plasma membrane, but not the mitochondria. In addition, the secretion of full-length enolase was inhibited in a knockout mutant of the intracellular SNARE protein-coding gene
TLG2
. Our results suggest that enolase is secreted via a SNARE-dependent secretory pathway in
S. cerevisiae
.
Cows-feet soup: a rare cause of recurrent trichobezoar
Authors: Kiernan Miles Finbar , Kamat Sachin , Olagbaiye Femi
Published: July 2012

A 45-year-old Afro-Caribbean woman attended the emergency department with worsening dysphagia, abdominal distension, abdominal pain, shortness of breath and generalised weakness. She enjoyed preparing and eating cows-feet stew and preferred to cook the meat with the hair and skin intact. On admission she had a severe microcytic anaemia and was malnourished. Abdominal x-ray and CT revealed a large gastric bezoar. At gastrotomy a foul-smelling 2.42 kg mass of hair, leathery skin and altered food were evacuated from the lesser curvature of the stomach. She had undergone the same procedure 8 years earlier to remove a similar trichobezoar.

Following psychiatric review it was deemed that the patient had no underlying psychiatric condition and had full insight into why her trichobezoar had re-occurred. She made a good postoperative recovery and stopped eating cows-feet stew.
Bee-sting, a non-resolving wound and a progressive mass over the right eye preceding the ultimate diagnosis of frontal bone Ewing's sarcoma
Authors: Gupta Manoj Kumar , Rastogi Madhup , Seam Rajeev Kumar , Revannasiddaiah Swaroop
Published: July 2012

A healthy young lady suffered a bee-sting over her right eyelid which was followed by pain, redness and swelling at, above and beyond the right eyelid. Although the initial swelling subsided, the patient noticed a small ‘lump’, superior to the eyelid which persisted after the rest of the swelling disappeared. This lump subsequently progressed over a span of 3 months and then caused ulceration of the overlying skin. Further testing revealed the lump to be an Ewing's sarcoma arising from the frontal bone. The patient was treated with standard chemotherapy (16 cycles of vincristine, doxorubicin, cyclophosphamide alternating with cycles of ifosfamide and etoposide) and radiotherapy and has remained disease-free 18-months after completion of treatment. This report reminds the reader about a not-so-uncommon mode of presentation of malignancies, that is, they being discovered after attention drawn by a rather common injury or trauma.
Generalised stunting of roots in an epileptic child: is long-term phenytoin therapy the cause?
Authors: Jindal Garima , Pandey Ramesh K , Kumar Dipanshu
Published: July 2012

Long-term phenytoin therapy is known to cause disturbance in calcium and bone homeostasis. Dental tissues being calcified tissues can also be affected by this derangement of mineral metabolism, especially during developmental phases. This report describes a case of an epileptic child who presented with short roots, enlarged pulp chambers, blunt apices and delayed eruption of permanent dentition, which might be attributed to long-term phenytoin therapy. The purpose of this case report is to increase awareness among the clinicians about its possible dental implications and emphasise upon the need of regular dental check-ups in epileptic children.
Paraneoplastic neurological syndrome as initial presentation of pulmonary adenocarcinoma
Authors: Shahani Lokesh
Published: July 2012

Paraneoplastic neurological syndromes are defined as remote effects of cancer that are not caused by the tumour and its metastasis, or by infection, ischaemia or metabolic disruptions. The author reports a 63-year-old Caucasian woman presenting with slowly progressing cognitive deficits. Initial workup failed to reveal any obvious cause of her cognitive deficits. Retrospective medical data review revealed a pulmonary nodule, which on further evaluation revealed pulmonary adenocarcinoma with metastatic spread to liver and spine. MRI of the brain did not reveal any metastatic lesion. Cerebrospinal fluid analysis revealed the presence of anti-Hu antibody and a diagnosis of limbic encephalitis was made. Limbic encephalitis is an inflammatory process localised to structures of the limbic system that produces cognitive impairment along with other neuropsychiatric symptoms. This case highlights the importance of considering paraneoplastic syndromes in patients presenting with cognitive deficits.
Acute carpal tunnel syndrome in a patient with haemophilia: Table 1
Authors: Mayne Alistair Ivan William , Howard Anthony , Kent Matthew , Banks Joanne
Published: July 2012

Acute carpal tunnel syndrome (CTS) is a rare surgical condition usually resulting from wrist trauma. We present the case of a young haemophilic man who developed acute CTS following trivial injury. The patient was initially managed conservatively but symptom progression resulted in carpal tunnel decompression. A literature review and management approach are presented. This is an important complication of haemophilia to be aware of as prompt conservative management can obviate the need for surgery. This case is useful in (a) highlighting the importance of considering a patient's medical history when formulating differential diagnoses and (b) outlining a management approach to this condition.
Asymptomatic spontaneous cervical and mediastinal emphysema: Figure 1
Authors: Ojima Hitoshi , Fukai Yasuyuki , Soda Makoto , Kuwano Hiroyuki
Published: July 2012

We report our experience with four patients presenting with spontaneous pneumomediastinum (SPM) within a 3-month period. The patients (three male and one female, aged 15–17 years) were hospitalised with SPM. All patients were kept under observation, successfully treated and followed up for several years, with no recurrences reported. Two patients had histories of asthma, while the other two developed SPM during sporting activities. SPM carries the possibility of being latent. For symptoms such as chest pain without evidence of pneumothorax in young people, it is necessary to always consider SPM and make the diagnosis accordingly.
Cutaneous tuberculosis caused by isoniazid-resistantMycobacterium tuberculosis
Authors: Asadi Gharabaghi Mehrnaz
Published: July 2012

Cutaneous tuberculosis constitutes an uncommon presentation of extrapulmonary tuberculosis, especially among immune-competent patients. Here, there is a report of a 38-year-old man who presented with non-pruritic skin plaques, caused by isoniazid-resistantMycobacterium tuberculosis, over his buttock, inguinal area and earlobe.
Effect of integrated palliative care on the quality of end-of-life care: retrospective analysis of 521 cancer patients
Authors: Colombet Isabelle , Montheil Vincent , Durand Jean-Philippe , Gillaizeau Florence , Niarra Ralph , Jaeger Cécile , Alexandre Jérôme , Goldwasser François , Vinant Pascale
Published: July 2012

Objective

To examine the impact of oncologist awareness of palliative care (PC), the intervention of the PC team (PCT) and multidisciplinary decision-making on three quality indicators of end-of-life (EOL) care.

Setting

Cochin Academic Hospital, Paris, 2007–2008.

Design and participants

A 521 decedent case series study nested in a cohort of 735 metastatic cancer patients previously treated with chemotherapy. Indicators were location of death, number of emergency room (ER) visits in last month of life and chemotherapy administration in last 14 days of life. Multivariable logistic regression models were used to estimate associations between indicators and oncologist's awareness of PC, PCT intervention and case discussions at weekly onco-palliative meetings (OPMs).

Results

58 (11%) patients died at home, 45 (9%) in an intensive care unit or ER, and 253 (49%) in an acute care hospital; 185 (36%) patients visited the ER in last month of life and 75 (14%) received chemotherapy in last 14 days of life. Only the OPM (n=179, 34%) independently decreases the odds of receiving chemotherapy in last 14 days of life (OR 0.5, 95% CI 0.2 to 0.9) and of dying in an acute care setting (0.3, 0.1 to 0.5). PCT intervention (n=300, 58%) did not independently improve any indicators. Among patients seen by the PCT, early PCT intervention had no impact on indicators, whereas the OPM reduced the odds of persistent chemotherapy in the last 14 days of life.

Conclusion

Multidisciplinary decision-making with oncologists and the PCT is the most critical parameter for improving EOL care.
Defining chronic cancer: patient experiences and self-management needs
Authors: Harley Clare , Pini Simon , Bartlett Yvonne Kiera , Velikova Galina
Published: July 2012

Objective

Chronic cancer is poorly defined and strategies for supporting patients during this disease phase are lacking. This research defines chronic cancer, explores patient experiences and reviews patients' support needs against those described in the 2007 Department of Health Generic Choice Model for Long-term Conditions (DoH-GCM).

Design

Semistructured interviews were audio recorded, transcribed and data explored for emergent themes. The a priori themes from DoH-GCM were applied: clinical support; self-care and self-management; supporting independence; psychological support; and social and economic factors.

Results

56 patients >12 months postdiagnosis of advanced cancer were recruited from five clinics at a Yorkshire cancer centre: breast (n=11); renal (n=11); colorectal/gastrointestinal (n=12); gynaecological (n=12); and prostate (n=10). Most patients aspired to livingnormallives. Challenges included frequent and lengthy hospital appointments, long-term symptom control and uncertainty. Only renal and prostate patients reported routine access to specialist nursing. Uptake of support services was varied and there was generally poor understanding of support pathways for non-medical problems and issues occurring when patients were not receiving active treatment. There was variation in coping strategies and ability of patients to attain a positive outlook on life.

Conclusions

For patients to do well in this cancer phase requires good self-management of symptoms plus taking an active role in accessing appropriate services as needed. Care planning at the point of transition to the chronic phase of cancer should focus on evaluating patients' needs, clarifying support pathways, increasing the profile and involvement of community services and organisations, and supporting patients and families develop effective self-management skills.
Age, period and cohort effects on the incidence of motorcyclist casualties in traffic crashes
Authors: Langley John , Samaranayaka Ari , Begg Dorothy J
Published: July 2012

Objectives

(1) Estimate age, period and cohort effects for motorcyclist traffic casualties 1979–2008 in New Zealand and (2) forecast the incidence of New Zealand motorcycle traffic casualties for the period 2019–2023 assuming future age, cohort and period effects, and compare these with an estimate based on simple linear extrapolation.

Methods

Age-period-cohort (APC) modelling was used to estimate the individual effects of age, period and cohort after adjusting for the other two factors. Forecasting was produced for three period-effect scenarios.

Results

After adjusting for cohort and period effects, 15–19-year-olds have substantially elevated risk. The period effect reduced in significance over time until the last period, 2004–2008, where the risk was higher than the preceding period. The 10-year cohorts born 1949–1958, 1954–1963, 1959–1968 and 1964–1973, had elevated risk. The forecasting, based on APC modelling, resulted in the lowest estimates of the future incidence being approximately one-third that of the highest estimate (6641).

Conclusion

Trends in motorcycle casualties have been influenced by significant independent age, period and cohort effects. These need to be considered in forecasting future casualties. The selection of the period effect has a significant impact on the estimates. Which period-effect scenario readers choose to accept depends on their views about a wide range of factors which might influence motorcycle use and crash risk over time.
Effectiveness of breed-specific legislation in decreasing the incidence of dog-bite injury hospitalisations in people in the Canadian province of Manitoba
Authors: Raghavan Malathi , Martens Patricia J , Chateau Dan , Burchill Charles
Published: July 2012

Background

The city of Winnipeg was the first among several jurisdictions in Manitoba, Canada, to introduce breed specific legislation (BSL) by banning pit-bull type dogs in 1990. The objective of the present work was to study the effectiveness of BSL in Manitoba.

Methods

Temporal differences in incidence of dog-bite injury hospitalisations (DBIH) within and across Manitoba jurisdictions with and without BSL were compared. Incidence was calculated as the number of unique cases of DBIH divided by the total person-years at risk and expressed as the number per 100 000 person-years. Year of implementation determined the pre-BSL and post-BSL period for jurisdictions with BSL; for jurisdictions without BSL to date, the entire study period (1984–2006) was considered as the preimplementation period. The annual number of DBIH, adjusted for total population at risk, was modelled in a negative binomial regression analysis with repeated measures. Year, jurisdiction and BSL implementation were independent variables. An interaction term between jurisdiction and BSL was introduced.

Results

A total of 16 urban and rural jurisdictions with pit-bull bans were identified. At the provincial level, there was a significant reduction in DBIH rates from the pre-BSL to post-BSL period (3.47 (95% CI 3.17 to 3.77) per 100 000 person-years to 2.84 (95% CI 2.53 to 3.15); p=0.005). In regression restricted to two urban jurisdictions, DBIH rate in Winnipeg relative to Brandon (a city without BSL) was significantly (p<0.001) lower after BSL (rate ratio (RR)=1.10 in people of all ages and 0.92 in those aged <20 years) than before (RR=1.29 and 1.28, respectively).

Conclusions

BSL may have resulted in a reduction of DBIH in Winnipeg, and appeared more effective in protecting those aged <20 years.
Drought-induced tree mortality: ecological consequences, causes, and modeling
Authors: Wang Weifeng , Peng Changhui , Kneeshaw Daniel D. , Larocque Guy R. , Luo Zhibin
Published: July 2012

Drought-induced tree mortality, which rapidly alters forest ecosystem composition, structure, and function, as well as the feedbacks between the biosphere and climate, has occurred worldwide over the past few decades, and is expected to increase pervasively as climate change progresses. The objectives of this review are to (1) highlight the likely ecological consequences of drought-induced tree mortality, (2) synthesize the hypotheses related to drought-induced tree mortality, (3) discuss the implications of current knowledge for modeling tree mortality processes under climate change, and (4) highlight future research needs. First, we emphasize the likely ecological consequences of tree mortality from ecosystem to biome to continental scales. We then document and criticize multiple non-exclusive tree mortality hypotheses (e.g., carbon starvation — carbon supply is less than carbon demand; and hydraulic failure — desiccation from failed water transport) from a more comprehensive ecological perspective. Next, we extend a forest decline concept model, Manion’s framework, by considering new emerging environmental conditions, for a more thorough understanding of the effects of climate change on forest decline. We find that an increase in drought frequency and (or) climate-change-type droughts may trigger increased background tree mortality rates and severe forest dieback events, accelerating species turnover and ecological regime shifts. The contribution of CO2 fertilization, rising temperature within the optimal growth range, and increased nitrogen deposition may defer or reduce this trend in tree mortality, but such contributions will vary between locations, species, and tree sizes. Multiple hypotheses proposed for drought-induced tree mortality are discussed, but coupling carbon and water cycles could help resolve the debate. The absence of a physiological understanding of tree mortality mechanisms limits the predictive ability of current models from stand-level process-based models to dynamic global vegetation models. We thus suggest that long-term observations, experiments, and models should be tightly interwoven during the research process to better forecast future climate changes and evaluate their impacts on forests.
Actual and general Manning–Rosen potentials under spin and pseudospin symmetries of the Dirac equation
Authors: Hassanabadi H. , Maghsoodi E. , Zarrinkamar S. , Rahimov H.
Published: July 2012

The so-called general and actual Manning–Rosen potentials have been investigated under spin and pseudospin symmetries of the Dirac equation in a comparative study. By approximating the centrifugal term, we have reported the analytical solutions to the problem via supersymmetry quantum mechanics. Illustrative figures and tables are included to discuss the problem in detail. The role of a Coulomb tensor interaction is investigated too. We see that the degenerate doublets are the same in both cases.
Geometric phase in quantum mechanics and calculation for spin one-half in a rotating magnetic field
Authors: Bracken Paul
Published: July 2012

A mathematical formalism for describing geometric phases is presented. A development of the geometric phase is given, which is valid for noncyclic nonadiabatic processes. The result is used to calculate exactly the geometric phase for a quantum system that is made up of a spin one-half system in a rotating magnetic field.
Change in properties of nano and bulk SrTiO3 crystals
Authors: Kulagin N.A. , Goroshkova L.A. , Hieckmann Е.
Published: July 2012

This paper describes selected properties of pure and doped strontium titanate single crystals. Data obtained using optical and cathode-luminescence, X-ray fluorescence, scanning electron microscope measurements of the crystals over plasma treatment, and crystallographic structure related oxidation state of the component and doped ions have been analyzed too. Colour centres in near stoichiometry crystals, quasi-ordered structures of nano-scale size pyramids generated by plasma flow on the surface, and ordered oxygen vacancy structures in the samples are presented in this paper.
Acoustic heating produced in resonators filled by a newtonian fluid
Authors: Perelomova Anna
Published: July 2012

Acoustic heating in resonators is studied. The governing equation of acoustic heating is derived by means of the special linear combination of conservation equations in differential form, allowing the reduction of all acoustic terms in the linear part of the final equation, but preserving terms belonging to the thermal mode responsible for heating. This equation is instantaneous and includes nonlinear acoustic terms that form a source of acoustic heating, it is valid for weakly nonlinear flows with weak attenuation. In general, dynamics of sound in a resonator is described by coupling nonlinear equations. Though the equation for heating relates to any sound field that may exist in a resonator, establishing a sound field is a problem itself. It is well known that employment of the different scales method and averaging over the sound period makes it possible to consider sound waves of opposite directions separately, without accounting for their interaction in the volume of the resonator, if they are periodic with zero mean perturbations. It also allows the adding together of contributions of oppositely propagating waves in the production of heat. Some examples of acoustic heating in resonators, relating to periodic sound branches with zero mean perturbations, are discussed.
DISPERSIONLESS BIGRADED TODA HIERARCHY AND ITS ADDITIONAL SYMMETRY
Authors: LI CHUANZHONG , HE JINGSONG
Published: July 2012

In this paper, we firstly give the definition of dispersionless bigraded Toda hierarchy (dBTH) and introduce some Sato theory on dBTH. Then we define Orlov–Schulman's [Formula: see text], [Formula: see text] operator and give the additional Block symmetry of dBTH. Meanwhile we give tau function of dBTH and some related dispersionless bilinear equations.
ANALYSIS AND DESIGN OF AN ABFT AND PARITY-CHECKING TECHNIQUE IN HIGH PERFORMANCE COMPUTING SYSTEMS
Authors: HAMIDI HODJAT , VAFAEI ABBAS , MONADJEMI SEYED AMIRHASSAN
Published: July 2012

We present a new approach to algorithm-based fault tolerance (ABFT) and parity-checking techniques in the design of high performance computing systems. The ABFT technique employs real convolution error-correcting codes to encode the input data. In order to reduce the round-off error from the output decoding process, systematic real convolution encoding is employed. This paper proposes an efficient method to detect the arithmetic errors using convolution codes at the output compared with an equivalent parity value derived from the input data. Number data processing errors are detected by comparing parity values associated with a convolution code. These comparable sets will be very close numerically, although not identical because of round-off error differences between the two parity generation processes. The effects of internal failures and round-off error are modeled by additive error sources located at the output of the processing block and input at threshold detector. This model combines the aggregate effects of errors and applies them to the respective outputs.
THE GENERATION OF POLARIZATION-ENTANGLED PHOTON PAIRS USING GRATING STRUCTURES OF Ti-DIFFUSED LITHIUM NIOBATE WAVEGUIDES IN INTEGRATED OPTICS
Authors: SALEMIAN SHAMSOLAH , MOHAMMADNEJAD SHAHRAM
Published: July 2012

Entangled photon source is an essential tool for quantum information experiments, such as tests of Bell inequalities, quantum teleportation, and entanglement swapping. We report the generation of polarization-entangled photon pairs using grating structures of nonlinear materials such as Ti -diffused Lithium Niobate. This approach is useful for quantum integrated optics because the size of this element is less than 325 micron. Polarization-entangled photon pairs are created using the nonlinear optical process of type-II spontaneous parametric down-conversion. The pump laser at 800 nm was doubled to a wavelength of 400 nm, which was used to produce SPDC in the grating structure of Lithium Niobate. The entangled photon pairs were generated at wavelengths 692 nm and 950 nm. The used grating structure consists of two sections. Grating period and length of the first section are 162 nm and 129.6 micron, respectively. Grating period of the second section is 193 nm and its length is equal to 193 micron.
ON THE ELECTRONIC DENSITY OF STATES IN INELASTIC ELECTRON TUNNELING SPECTROSCOPY
Authors: GRADO-CAFFARO M. A. , GRADO-CAFFARO M.
Published: July 2012

In agreement with experimental results relative to acetylene and deuterated-acetylene molecules on copper, a quantitative study relative to electronic density of states and tunneling current in terms of voltage is carried out within the context of inelastic electron tunneling spectroscopy. Our starting point is regarding the corresponding differential tunneling conductance as a function of the tunneling voltage. In particular, as a relevant figure of merit, the first derivative of the above conductance is determined. A numerical computation relative to this figure of merit is also carried out.
SUPPORTING IT IMPLEMENTATION DECISIONS WITH ANP — SUPPLIER SCHEDULING FOR e-INVOICING
Authors: KIVIJÄRVI HANNU , HALLIKAINEN PETRI , PENTTINEN ESKO
Published: July 2012

Companies aim to make their supply chains more efficient by using modern information technology (IT). Owing to limited resources there is a need to prioritize IT projects and those generating the highest business value should be implemented first. In this paper, we first develop the theoretical foundations for the prioritization decision and then implement the theoretical principles by applying the ANP (analytic network process) approach. A model is developed to aid a buyer company in selecting prioritized suppliers for adopting electronic invoicing. The case company is a leading Finnish textile and clothing design company. The ANP approach is considered suitable for this type of decision problem with many interconnected decision-making criteria. As the result of the analysis, the prioritized suppliers, representing different supplier types in the case company, are determined. The results can be applied to schedule e-invoicing implementation projects among the supplier companies. Based on the case study it can be concluded that the theoretical principles and the ANP approach can also be applied to other IT implementation decisions concerning supply chain efficiency.
The Support of Knowledge Process to Enhance Risk Analysis in Jordanian Telecommunication Companies
Authors: Karadsheh Louay , Alhawari Samer , Talet Amine Nehari
Published: July 2012

The purpose of this paper is to study how Jordanian companies use the knowledge process to support risk analysis and how they deal with and foster it. The present empirical study is based on a sample of the data collected from 180 respondents, drawn randomly from Jordanian Telecommunication Companies. It provides a contribution to the literature about knowledge-based risk analysis in one of the developing countries as a framework to keep organisations competitive within the global business environment.

This paper makes the following contributions. First, it demonstrates that according to project stakeholders, individual risk management activities, like for instance risk identification, are able to contribute to project success.

Second, this paper provides insight in how knowledge process to support risk analysis and how they deal with and foster risk management activities to contribute in IT project success.

And third, based on this new perspective, this paper provides new directions for further research into the mechanisms on how knowledge process support risk analysis in risk management to contribute in IT project success.

The results of the survey show that the four selected factors (knowledge-based risk rationalise, knowledge-based risk comprehension, knowledge-based risk examination, and knowledge-based risk validation) have a significant impact on risk analysis.

Due to the literature limitation about the KM model in developing countries, the current study will contribute to this field by addressing the knowledge-based risk. The findings will certainly help both researchers and practitioners in future knowledge management (KM) process, and risk analysis research. In order to get a better understanding of the knowledge processes on risk analysis, future research endeavours should focus on several other countries for comparative purposes.
A Comparative Study of Trust as a Knowledge Sharing Enabler and its Influence on Organisational Culture
Authors: Al Hawari Maen
Published: July 2012

Measuring organisational trust gives stakeholders many indicators of their organisations. These indicators are performance, leadership, employees' satisfaction, job satisfaction, and knowledge sharing culture. In addition to that, the highest levels of organisations' trust can critically reduce conflict charges and transaction costs.

This paper is the first stage of a research study that discusses the importance of trust to knowledge sharing. This paper shows to what extent culture influences organisational trust compared with the global trust index. This research adopts a model of trust with five dimensions and they are relating to knowledge sharing in an organisation; concern for employees, openness and honesty, identification, reliability, and competence. The adopted model was used to develop the global trust index. A survey of 26 different items was conducted on 135 profitable organisations in Jordan in different industries. A total of 397 questionnaires were returned in a form eligible for the analysis.

The results show that the overall organisational trust index in Jordan compared with the global index is low and the difference is significant. Furthermore, all trust dimensions in Jordan have lower values than the world's trust dimensions. Locally, the openness and honesty dimension has the highest value, and the competency dimension has the lowest value. Therefore, Jordanian culture significantly affects the trust index in the country and lowers it compared with the global trust index.
MODELING AND SIMULATION OF MICRO-SCALE WIND FARMS USING HIGH PERFORMANCE COMPUTING
Authors: HUSSEIN ASHRAF S. , EL-SHISHINY HISHAM E.
Published: July 2012

Onshore wind farms usually consist of numerous horizontal axis wind turbines closely placed in clusters, and they are often cited on complex terrain. This paper proposes a computational framework for modeling and simulation of wind flow over micro-scale (and early meso-scale) wind farms using distributed memory, massively parallel high performance computing platforms. The present framework uses the Reynolds Averaged Navier–Stokes (RANS) to model the wind flow over the wind farms, as the flow is considered to be fully turbulent, isothermal and incompressible. The wind turbines installed in the wind farm are modeled by the virtual blade model (VBM). This technique considers the presence of a wind turbine's rotor implicitly through momentum sources placed in an actuator disc, yielding indirectly a pressure jump across the disk, which varies with its radius and azimuth. The nonlinear, aerodynamic interaction between the rotor wakes with each other and with the terrain of the wind farm is simulated by coupling the VBM with the governing flow field equations. In this manner, an efficient parallel algorithm for implementing the VBM was developed and integrated with parallel computational fluid dynamics (CFD) core simulation engine. The accuracy and performance of the proposed framework were confirmed through several test cases carried out on the IBM Blue Gene ultra-scale supercomputer.
VARIATION OF PARAMETERS METHOD FOR SOLVING A CLASS OF EIGHTH-ORDER BOUNDARY-VALUE PROBLEMS
Authors: NOOR MUHAMMAD ASLAM , INAYAT NOOR KHALIDA , WAHEED ASIF , Al-SAID EISA
Published: July 2012

In this paper, we use the variation of parameters method to solve a class of eighth-order boundary-value problems. The analytical results are calculated in terms of convergent series. Error estimates are tabulated and are compared with some other well known techniques which reveal the complete reliability of the suggested scheme. Several examples are given to verify the reliability and efficiency of the proposed method.
A GENERAL TECHNIQUE FOR COUPLING TWO ARBITRARY METHODS IN STRESS ANALYSIS
Authors: HEMATIYAN MOHAMMAD RAHIM , KHOSRAVIFARD AMIR , MOHAMMADI MEHRDAD
Published: July 2012

In this paper, a general technique for coupling two arbitrary methods is presented. The problem domain is decomposed into two sub-domains. Afterwards, a sensitivity analysis at the interface of each sub-domain is carried out. Sensitivity matrices of the two sub-domains are used to find the coupling matrix equation. Unknowns at the interface are then found by solving the equations. The size of the matrix equation is very small in comparison with coefficient matrices of each sub-domain. The present method allows the black box coupling of different methods, even commercial software without having access to the matrices created by the methods.
Adaptive Persuasive Systems
Authors: Kaptein Maurits , De Ruyter Boris , Markopoulos Panos , Aarts Emile
Published: July 2012

This article describes the use of personalized short text messages (SMS) to reduce snacking. First, we describe the development and validation (
N
 = 215) of a questionnaire to measure individual susceptibility to different social influence strategies. To evaluate the external validity of this Susceptibility to Persuasion Scale (STPS) we set up a two week text-messaging intervention that used text messages implementing social influence strategies as prompts to reduce snacking behavior. In this experiment (
N
 = 73) we show that messages that are personalized (tailored) to the individual based on their scores on the STPS, lead to a higher decrease in snacking consumption than randomized messages or messages that are not tailored (contra-tailored) to the individual. We discuss the importance of this finding for the design of persuasive systems and detail how designers can use tailoring at the level of social influence strategies to increase the effects of their persuasive technologies.
Interaction with the dirty, dangerous, and dull
Authors: Heyer Clint , Husøy Kristoffer
Published: July 2012

The boundaries between 'the digital' and our everyday physical world are dissolving as we develop more physical ways of interacting with computing. This forum presents some of the topics discussed in the colorful multidisciplinary field of tangible and embodied interaction.

Eva Hornecker, Editor
Reasoning about Web Applications
Authors: Boudol Gérard , Luo Zhengqin , Rezk Tamara , Serrano Manuel
Published: July 2012

We propose a small-step operational semantics to support reasoning about Web applications written in the multitier language HOP. The semantics covers both server side and client side computations, as well as their interactions, and includes creation of Web services, distributed client-server communications, concurrent evaluation of service requests at server side, elaboration of HTML documents, DOM operations, evaluation of script nodes in HTML documents and actions from HTML pages at client side. We also model the browser same origin policy (SOP) in the semantics. We propose a safety property by which programs do not get stuck due to a violation of the SOP and a type system to enforce it.
Discovering configuration templates of virtualized tenant networks in multi-tenancy datacenters via graph-mining
Authors: Himura Yosuke , Yasuda Yoshiko
Published: July 2012

Multi-tenant datacenter networking, with which multiple customer (tenant) networks are virtualized over a single shared physical infrastructure, is cost-effective but poses significant costs on manual configuration. Such tasks would be alleviated with configuration templates, whereas a crucial difficulty stems from creating appropriate (i.e., reusable) ones. In this work, we propose a graph-based method of mining configurations of existing tenants to extract their recurrent patterns that would be used as reusable templates for upcoming tenants. The effectiveness of the proposed method is demonstrated with actual configuration files obtained from a business datacenter network.
Moving towards a socially-driven internet architectural design
Authors: Sofia Rute , Mendes Paulo , Damásio Manuel José , Henriques Sara , Giglietto Fabio , Giambitto Erica , Bogliolo Alessandro
Published: July 2012

This paper provides an interdisciplinary perspective concerning the role of prosumers on future Internet design based on the current trend of Internet user empowerment. The paper debates the prosumer role, and addresses models to develop a symmetric Internet architecture and supply-chain based on the integration of social capital aspects. It has as goal to ignite the discussion concerning a socially-driven Internet architectural design.
Observation tools for effective schedules in a RTOS
Authors: Bikienga Moustapha , Geniet Dominique , Choquet-Geniet Annie
Published: July 2012

Real-time scheduling validation usually stands on emulators: the scheduling policy is validated, not the effective scheduler. We propose a strategy to calibrate scheduling observers, that aim to validate effective implementations of schedules.