bluuebunny/crossref_metadata_2025 huggingface dataset:
A meta‐analysis comparing laparoscopic partial versus Nissen fundoplication
Authors: Ma Shijie , Qian Bingbing , Shang Li , Shi Ruihua , Zhang Guoxin
Published: January 2011

Background:  For proven gastro‐oesophageal reflux disease, partial fundoplication is considered as effective as Nissen, but with fewer side effects. The aim of this meta‐analysis was to compare the effect of laparoscopic partial fundoplication (LPF) with laparoscopic Nissen fundoplication (LNF).

Methods:  Extensive medical literature searches of the PubMed, Medline and Embase databases were performed up to April 2010 for all randomized clinical trials that compared LPF versus LNF. The effect variables analysed were the incidence of post‐operative dysphagia, heartburn, inability to belch, outcome or satisfaction and Visick score. Meta‐analyses were carried out using odds ratios (ORs) with 95% confidence interval.

Results:  Thirteen randomized trials were considered suitable for the meta‐analysis. A total of 1374 patients underwent LPF or LNF. There was a significant reduction of the incidence of post‐operative dysphagia (OR = 0.44, P < 0.0001) and inability to belch (OR = 0.41, P < 0.005) for the LPF compared to that of the LNF group. Compared with LPF, LNF resulted in a significant reduction of the incidence of post‐operative heartburn (OR = 1.94, P < 0.01). The outcome or satisfaction of patients and Visick I and II scores were comparable between the two groups.

Conclusion:  Both LPF and LNF are effective for the treatment of proven gastro‐oesophageal reflux disease. LPF enables a decreased post‐operative dysphagia and gas‐related side effects, while LNF is more successful in controlling reflux symptoms, particularly heartburn, than LPF. A balance should be found between anti‐reflux and side effects.
Experiences of working with induced abortion: focus group discussions with gynaecologists and midwives/nurses
Authors: Lindström Meta , Wulff Marianne , Dahlgren Lars , Lalos Ann
Published: January 2011

Scand J Caring Sci; 2011; 25; 542–548
 
Experiences of working with induced abortion: focus group discussions with gynaecologists and midwives/nurses

Background:  While there exists an extensive amount of research regarding the medical aspects of abortion, there is a great lack of studies investigating staff’s views and experiences of working in abortion services.

Aims:  To elucidate gynaecologists’ and midwives’/nurses’ experiences, perceptions and interactions working in abortion services, their experiences of medical abortions and abortions performed at the woman’s home. An additional aim was to illustrate gynaecologists’, midwives’ and nurses’ visions of their future professional roles within the abortion services.

Method:  Three focus group discussions within each profession were carried out in 1‐hour sessions with a total of 25 gynaecologists and 15 midwives/nurses from three different hospitals.

Results:  The content analysis reflected that gynaecologists and midwives/nurses had no doubts about participating in abortions despite the fact that they had experienced complex and difficult situations, such as repeat and late‐term abortions. They experienced their work as paradoxical and frustrating but also as challenging and rewarding. However, they were rarely offered ongoing guidance and continuously professional development education. For gynaecologists, as well as midwives/nurses, their experiences and perceptions were strongly linked to the concurrent development of abortion methods. The interaction between the professions was found to be based on great trust in each other’s skills.

Conclusions:  In order to promote women’s health, gynaecologists’ and midwives’/nurses’ need for a forum for reflection and ongoing guidance should be acted on. With a higher number of abortions done medically and a higher proportion of home abortions, midwives/nurses will get increased, responsibilities in the abortion services in the future.
G protein‐coupled oestrogen receptor 1 (GPER1)/GPR30: a new player in cardiovascular and metabolic oestrogenic signalling
Authors: Nilsson Bengt‐Olof , Olde Björn , Leeb‐Lundberg LM Fredrik
Published: January 2011

Oestrogens are important sex hormones central to health and disease in both genders that have protective effects on the cardiovascular and metabolic systems. These hormones act in complex ways via both genomic and non‐genomic mechanisms. The genomic mechanisms are relatively well characterized, whereas the non‐genomic ones are only beginning to be explored. Two oestrogen receptors (ER), ERα and ERβ, have been described that act as nuclear transcription factors but can also associate with the plasma membrane and influence cytosolic signalling. ERα has been shown to mediate both anti‐atherogenic effects and pro‐survival effects in pancreatic β‐cells. In recent years, a third membrane‐bound ER has emerged, G protein‐coupled receptor 30 or G protein‐coupled oestrogen receptor 1 (GPER1), which mediates oestrogenic responses in cardiovascular and metabolic regulation. Both GPER1 knock‐out models and pharmacological agents are now available to study GPER1 function. These tools have revealed that GPER1 activation may have several beneficial effects in the cardiovascular system including vasorelaxation, inhibition of smooth muscle cell proliferation, and protection of the myocardium against ischaemia/reperfusion injury, and in the metabolic system including stimulation of insulin release and protection against pancreatic β‐cell apoptosis. Thus, GPER1 is emerging as a candidate therapeutic target in both cardiovascular and metabolic disease.

LINKED ARTICLES This article is one of a set of reviews submitted to BJP in connection with talks given at the September 2010 meeting of the International Society of Hypertension in Vancouver, Canada. To view the other articles in this collection visit http://dx.doi.org/10.1111/j.1476‐5381.2010.01167.x, http://dx.doi.org/10.1111/j.1476‐5381.2011.01260.x and http://dx.doi.org/10.1111/j.1476‐5381.2011.01366.x
R2D2for C4Eo: an ‘alliance’ of PGD2receptors is required for LTC4production by human eosinophils
Authors: Mackay Graham A , Stewart Alastair G
Published: January 2011

Eosinophils play important roles in limiting parasitic infection and in allergic inflammation in the asthmatic airways. Activation of eosinophils by diverse stimuli, including prostaglandin D2(PD2), leads to leukotriene C4(LTC4) synthesis that contributes to the expulsion of parasites and to epithelial injury in allergic inflammation. Mesquita‐Santoset al. in this issue of the journal describe a collaboration between the two PGD2receptors, DP1and DP2[also known as CRTH2 (chemoattractant receptor‐homologous molecule expressed on Th2 lymphocytes)] that is required to trigger LTC4synthesis. DP1receptors coupled to Gαsincrease adenylate cyclase activity and cAMP/ protein kinase A–dependent formation of lipid bodies, and DP2receptors coupled to Gαiincrease calcium. Each of these signals is required for LTC4production. These observations lead to consideration of the effects of other stimuli for eosinophil cAMP, such as the β2‐adrenoceptor agonists, which inhibit rather than enhance LTC4production.

LINKED ARTICLEThis article is a commentary on Mesquita‐Santoset al., pp. 1674–1685 of this issue. To view this paper visithttp://dx.doi.org/10.1111/j.1476‐5381.2010.01086.x
Comparison of two questionnaires to assess gastrointestinal toxicity in dogs and cats treated with chemotherapy*
Authors: Malone E. K. , Rassnick K. M. , Bailey D. B. , Kiselow M. A. , Erb H. N.
Published: January 2011

Questionnaires completed by pet owners are widely used instruments to monitor adverse gastrointestinal (GI) effects in the owners' animals undergoing chemotherapy and for reporting toxicoses in clinical trials; however, no questionnaires have been formally evaluated. This study compares two questionnaire‐based evaluations of adverse GI events: a basic, open‐ended questionnaire and a detailed questionnaire modelled after the grading in the Veterinary Co‐operative Oncology Group‐Common Terminology Criteria for Adverse Events (VCOG‐CTCAE). Owners completed both questionnaires after their dog or cat received moderately emetogenic chemotherapy. Results were used to derive toxicity grades for anorexia, vomiting and diarrhoea. We evaluated 123 pairs of questionnaires. Disagreement in grade of anorexia, vomiting and diarrhoea was found in 24, 7 and 13% of paired questionnaires, respectively (κ = 0.63, 0.83 and 0.71, respectively). Although ‘good’ to ‘very good’ agreement was found, the potential for only ‘fair’ agreement between questionnaire methods is of concern and suggests a need to adopt a standardized form.
Adipokines and psoriasis
Authors: Gerdes Sascha , Rostami‐Yazdi Martin , Mrowietz Ulrich
Published: January 2011

Abstract:  Adipose tissue is an active endocrine organ contributing to the regulation of multiple metabolic pathways via self‐produced bioactive products called adipokines. These adipokines are key players in the pathogenesis of metabolic syndrome and cardiovascular diseases. Co‐occurrence of obesity and psoriasis could lead to interactions of both diseases in which adipokines, at least in part, are involved and may contribute to associated comorbidities of psoriasis. Until today numerous adipokines have been identified of which the most important ones are discussed in the following within the context of obesity, chronic inflammation and their possible role in the pathogenesis of psoriasis. Adipokines could serve as a missing link in the causal relationship between psoriasis and comorbidities and may provide a biomarker for disease severity, risk of comorbidities and treatment success.
Distribution of melatonin receptors in murine pancreatic islets
Authors: Nagorny Cecilia L. F. , Sathanoori Ramasri , Voss Ulrikke , Mulder Hindrik , Wierup Nils
Published: January 2011

Abstract:  Melatonin has multiple receptor‐dependent and receptor‐independent functions. At the cell membrane, melatonin interacts with its receptors MT1 and MT2, which are expressed in numerous tissues. Genome‐wide association studies have recently shown that the MTNR1B/MT2 receptor may be involved in the pathogenesis of type 2 diabetes mellitus. In line with these findings, expression of melatonin receptors has been shown in mouse, rat, and human pancreatic islets. MT1 and MT2 are G‐protein‐coupled receptors and are proposed to exert inhibitory effects on insulin secretion. Here, we show by immunocytochemistry that these membrane melatonin receptors have distinct locations in the mouse islet. MT1 is expressed in α‐cells while MT2 is located to the β‐cells. These findings help to unravel the complex machinery underlying melatonin’s role in the regulation of islet function.
Research in practice: IL‐22 and IL‐20: significance for epithelial homeostasis and psoriasis pathogenesis
Authors: Sabat Robert , Wolk Kerstin
Published: January 2011

Psoriasis vulgaris is a frequent, chronically relapsing, immune‐mediated, systemic disease with characteristic skin changes. Despite the importance of this disease there are currently limited therapeutic options indicating a need for effective, long‐lasting treatment strategies with few side effects. The most recent discoveries regarding psoriasis pathogenesis, particularly our results regarding two cytokines – IL‐22 and IL‐20 – could prove to be the foundation for such therapies. Whereas IL‐22 is mainly produced by activated T‐cell sub‐populations (Th22, Th1, Th17), monocytes, dendritic cells and keratinocytes produce IL‐20. Blood and lesional skin samples from psoriasis patients demonstrate high levels of IL‐22 and IL‐20. Interestingly, both cytokines act principally on keratinocytes and do not impact the immune system. Similar to the changes in the psoriasis epidermis these cytokines inhibit the terminal differentiation of keratinocytes although they simultaneously increase their innate defense, mobility, and the production of some chemokines. Some IL‐22 effects are amplified by TNF‐α, IL‐17, and IFN‐α. IL‐22/IL‐20 lends the reconstructed epidermis a psoriasis‐like appearance with acanthosis, hypogranularity, and hyperkeratosis. In addition, mice that constitutively express high levels of IL‐22 or IL‐20 demonstrate a psoriasis‐like appearance. A therapy counteracting IL‐22 and IL‐20 would be an innovative treatment with the potential for few side effects that would act on the final phase of psoriasis pathogenesis.
Genome‐wide analysis of fungal manganese transporters, with an emphasis on Phanerochaete chrysosporium
Authors: Diss Loic , Blaudez Damien , Gelhaye Eric , Chalot Michel
Published: January 2011

Genome‐wide analysis of fungal manganese transporters was undertaken, making use of whole genome sequences available in fungal databases. A repertoire of 281 putative manganese transporters was found in total across 26 fungal species representing 20 fungal orders. The process of gene duplication was apparently accompanied by gene loss events, and this resulted in a great variety of manganese transporters that can be observed in the genome of modern fungi. Eleven transporters belonging to gene families in which manganese transporters have been found were identified in the Phanerochaete chrysosporium genome. This whole set of transporters may cover the need of P. chrysosporium cells for manganese loading in and unloading out of the cytosol, thereby insuring manganese homeostasis. The tight control of intracellular Mn2+ ion concentration is for instance of crucial importance for the control of lignin‐degradative systems by saprotrophic fungi, and thereof the carbon cycle in forest ecosystems.
Using Multicell Kelvin Structure for Pressure Vessel
Authors: Zhang P. , Du R.
Published: January 2011

Pressure vessel is widely used in many engineering areas. How to achieve a perfect combination of excellent performance and low cost in the design and manufacturing of a pressure vessel is, therefore, very important. Instead of a single cylinder, a multicell pressure vessel with a Kelvin structure is proposed in this paper. It is found that such structure offers not only improved safety but also extra storage capacity. This may lead to a type of pressure vessel suitable for stringent applications, even without employing costly materials.
Failure of Ductile Materials Subject to Varying Strain Rates
Authors: Kwon Y. W. , Tan K. S.
Published: January 2011

Strain rate affects the mechanical properties of ductile materials in terms of their stiffness and strength. In particular, yield and failure strengths and strains depend on the strain rate applied to the materials. When a metallic material is subjected to a typical dynamic loading, the material usually undergoes various strain-rate loading conditions. One of the main questions is whether the material is going to fail or not. To the authors’ best knowledge, there has been no failure criterion proposed for a varying strain-rate loading condition. This paper presents a failure criterion under nonuniform strain-rate loading conditions. Experiments were conducted to support the proposed failure criterion using aluminum alloy AA3003-H14. This study also investigated the that failure envelops in terms of strain rates and the normalized failure strengths. Furthermore, the effects of strain rates on strength and stiffness properties were also examined.
Collective buckling of line arrays created by soft lithography
Authors: Chen Ziguang , Yang Jiashi , Tan Li
Published: January 2011

The authors analyze the collective buckling of an array of elastic lines with their lower edges built into an elastic substrate of the same material. These lines can interact among themselves through the deformation of the substrate. From the theory of elasticity and elastic structures, an eigenvalue problem is formulated and solved. Calculations show that the lines can buckle collectively into certain ordered patterns, where some of which have been confirmed by experiments. The results are useful for the understanding, design, and application of the nanostructures produced by soft lithography and other embossing techniques.
Annealing temperature dependence of Ohmic contact resistance and morphology on InAlN/GaN high electron mobility transistor structures
Authors: Lo C.-F. , Liu L. , Chang C. Y. , Ren F. , Craciun V. , Pearton S. J. , Heo Y. W. , Laboutin O. , Johnson J. W.
Published: January 2011

Ti/Al/Ni/Au Ohmic contact metallization on InAlN/GaN heterostructures both with and without a thin GaN cap layer was annealed at different temperatures. The minimum transfer resistance for the contacts of 0.65 Ω  mm (specific contact resistivity of 2×10−5 Ω cm2) was achieved after 800 °C annealing for structures without the GaN cap, while those with the cap exhibited their lowest resistance at higher temperatures. The contact morphology showed considerable roughening by 750 °C but the carrier mobility was stable until annealing temperatures of 850 °C. Diffuse scattering experiments showed that the morphological roughness of the InAlN/GaN interface increased as a result of annealing at these temperatures and the data were consistent with outdiffusion of Ga into the InAlN. Unpassivated high electron mobility transistors with a gate dimension of 0.7×180 μm2 were fabricated using these contacts and showed a maximum drain current of 1.3 A/mm and an extrinsic transconductance of 366 mS/mm. The presence of the GaN cap increased the effective barrier height of Ni/Au Schottky contacts from 0.91 to 1.01 eV on the heterostructure.
Synthesis and Measurement of Ultrafast Waveforms from Five Discrete Optical Harmonics
Authors: Chan Han-Sung , Hsieh Zhi-Ming , Liang Wei-Hong , Kung A. H. , Lee Chao-Kuei , Lai Chien-Jen , Pan Ru-Pin , Peng Lung-Han
Published: January 2011

Optical fields have been manipulated like radio frequencies into sawtooth and square-wave patterns.
Colorectal cancer detection: time to abandon barium enema?
Authors: Shariff M K , Sheikh K , Carroll N R , Whitley S , Greenberg D , Parkes M , Cameron E A B
Published: January 2011

Objectives

To assess the sensitivity of double contrast barium enema (DCBE) for diagnosing colorectal cancer (CRC).

Design

Retrospective evaluation of DCBE performed in the 2 years prior to diagnosis of CRC.

Setting

Teaching hospital in Cambridge, UK.

Patients

1310 consecutive cases of CRC identified from cancer registry data.

Interventions

DCBE and colonoscopy.

Main outcome measures

Sensitivity of DCBE for diagnosing CRC.

Results

215 patients had undergone a DCBE within the 2 years prior to diagnosis with CRC. After excluding those reported as inadequate, 37 of these were reported as normal, giving a sensitivity of 83% (81–85%).

Conclusions

The performance of DCBE is inadequate for the exclusion of CRC. Expansion of colonoscopy and CT colonography capacity is urgently required nationally so that DCBE can finally be abandoned as a firstline test in patients at risk of CRC.
A defence of a new perspective on euthanasia
Authors: Shaw David
Published: January 2011

In two recent papers, Hugh McLachlan, Jacob Busch and Raffaele Rodogno have criticised my new perspective on euthanasia. Each paper analyses my argument and suggests two flaws. McLachlan identifies what he sees as important points regarding the justification of legal distinctions in the absence of corresponding moral differences and the professional role of the doctor. Busch and Rodogno target my criterion of brain life, arguing that it is a necessary but not sufficient condition and that it is not generalisable. In this paper I indicate flaws in all of these criticisms, and again suggest that my perspective does add something new to the debate.
Comment on “Wetland drying and succession across the Kenai Peninsula Lowlands, south-central Alaska”Appears in Can. J. For. Res. 35: 1931-1941 (2005).
Authors: Gracz Michael B.
Published: January 2011

Klein et al. (2005, Can. J. For. Res. 35: 1931–1941) compare aerial photographs and report dramatically lower lake levels on the northern Kenai Peninsula, Alaska. They hypothesize that the lower lake levels may be caused by a decline in moisture surplus driven by climate change. However, the reported decline in surplus appears to be insufficient to explain the lower lake levels. Here I develop a simple sensitivity analysis to test their hypothesis and also show how tectonic processes such as the Great Alaskan earthquake could dramatically lower lake levels by fracturing an underlying aquitard. Tectonic processes, therefore, could potentially alter forest succession and wetland ecosystems by inducing hydrologic changes that mimic changes in climate.
Influence of Global Navigation Satellite System errors in positioning inventory plots for tree-height distribution studiesThis article is one of a selection of papers from Extending Forest Inventory and Monitoring over Space and Time.
Authors: Mauro F. , Valbuena R. , Manzanera J. A. , García-Abril A.
Published: January 2011

Validation of predictive models in remote sensing requires a good coregistration of field and sensor data sets. However, previous research has demonstrated that Global Navigation Satellite System survey techniques often produce large positioning errors when applied to areas under forest canopies. In this article, we present a repeatable methodology for analyzing the effect of such errors when validating models that predict tree-height distributions from LiDAR data sets. The method is based on conditional probability theory applied to error positioning and includes an error assessment of the surveying technique. A technical criterion for selecting the plot radius that avoids significant effects of positioning errors was proposed. We demonstrated that for a plot radius greater than 10 m, the effects of positioning errors introduced by a phase-differential device were insignificant when studying forest tree-height distributions.
Effects of climate on growth of lodgepole pine and white spruce following site preparation and its implications in a changing climate
Authors: Cortini Francesco , Comeau Philip G. , Boateng Jacob O. , Bedford Lorne , McClarnon John , Powelson Allan
Published: January 2011

Site preparation and vegetation control can be used to mitigate climate change effects on early plantation growth in boreal forests. In this study, we explored growth of lodgepole pine ( Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) and white spruce ( Picea glauca (Moench) Voss) in relation to climate and site preparation using 20 years of data collected from studies in British Columbia. Results indicate that up to 45% of the variation in spruce growth and up to 37% of the variation in pine growth over this 20-year period can be explained by selected climatic variables. Monthly climate variables showed a stronger relationship to conifer growth than seasonal and annual variables. Climate variables related to the preceding year accounted for more than half of the variables in the final equations, indicating a lagged response in conifer growth. Future projections indicated that height growth of young lodgepole pine plantations in the sub-boreal zone could benefit (in the short term) from longer growing seasons by up to 12% on untreated stands. Untreated young white spruce plantations in the boreal zone may suffer height growth decreases of up to 10% due to increased drought stress. Vegetation control and mechanical site preparation treatments appear to mitigate effects of climate change to some extent.
Effects of climate warming on canopy water dynamics of a boreal black spruce plantation
Authors: Van Herk Ingrid G. , Gower Stith T. , Bronson Dustin R. , Tanner Myron S.
Published: January 2011

The purpose of this study was to quantify the effects of climate change (in the form of elevated air and soil temperatures) on transpiration and sap flux rates of black spruce ( Picea mariana (Mill.) BSP). Five treatments were established in northern Manitoba, Canada, with the experimental design consisting of heated and control blocks. Air and soil temperatures were maintained approximately 5 °C above control temperatures using greenhouse chambers. Two of the chambers also included controls to maintain ambient vapor pressure difference (VPD). Sap flux (JS), was not significantly different among treatments in the May or July time periods. However, JS was significantly greater for heated VPD controlled trees than for trees in all other treatments when averaged over the entire study period. JS was positively correlated to photosynthetic photon flux density for all trees. Lower photosynthetic photon flux density in chamber treatments resulted in the creation of models used to estimate JS and canopy transpiration (EC) values that were used in the analysis. Average daily and cumulative growing season EC values were significantly greater for the heated VPD controlled treatments than for other treatments. The results from this study suggest that EC of boreal black spruce will increase if VPD remains unchanged while air temperatures increase.
Assessment of weather-associated causes of red spruce winter injury and consequences to aboveground carbon sequestration
Authors: Schaberg Paul G. , Lazarus Brynne E. , Hawley Gary J. , Halman Joshua M. , Borer Catherine H. , Hansen Christopher F.
Published: January 2011

Despite considerable study, it remains uncertain what environmental factors contribute to red spruce ( Picea rubens Sarg.) foliar winter injury and how much this injury influences tree C stores. We used a long-term record of winter injury in a plantation in New Hampshire and conducted stepwise linear regression analyses with local weather and regional pollution data to determine which parameters helped account for observed injury. Two types of weather phenomena were consistently associated with elevated injury: (i) measures of low-temperature stress that incite injury and (ii) factors that reduced the length of the growing season and predisposed trees to injury. At this plantation, there was a significant linear relationship between winter injury and growth reductions for 2 years after a severe winter injury event. Analysis using data from three New England states indicated that plantation data reflected a regional response. Using regional data, we estimated a reduction of 394 000 metric tons of C sequestered in living red spruce stems ≥20 cm in diameter growing in New York and northern New England during the 2 years following a severe winter injury event. This is a conservative estimate of reduced C sequestration because injury-induced mortality and other factors were not evaluated.
Genetic mapping of linkage group XIX and identification of sex-linked SSR markers in a Populus tremula × Populus tremuloides cross
Authors: Pakull Birte , Groppe Katrin , Mecucci Federica , Gaudet Muriel , Sabatti Maurizio , Fladung Matthias
Published: January 2011

A progeny of 130 F1individuals of an interspecific cross between Populus tremula L. and Populus tremuloides Michx. was used for genetic mapping of linkage group XIX with SSR markers based on the Populus trichocarpa Torr. & A. Gray genome sequence. Several fully sex-linked SSR markers were identified and mapped to a central position on the male P. tremuloides map of linkage group XIX. For the SSR markers tested here, the position on the assembled P. trichocarpa genome sequence is known, allowing sex-linked markers to be assigned to the central region of scaffold/chromosome 19 of P. trichocarpa. The sex linkage of the SSR markers was validated in other P. tremula × P. tremuloides crosses and also tested in Populus alba L. and Populus nigra L.
Oregon design professionals views on structural building products in green buildings: implications for wood
Authors: Knowles Chris , Theodoropoulos Christine , Griffin Corey , Allen Jennifer
Published: January 2011

Buildings have been shown to have impacts on the environment. Consequently, green building rating systems have become a tool to help reduce these impacts. The objectives of this study were to identify gaps in information and access to green building materials as viewed by Oregon design professionals. The scope was limited to the major structural materials: concrete, steel, and wood. This article focuses on the results unique to wood products. Information was collected through group interviews. Each group was composed of professionals representing different aspects of material selection and construction of different scales. The results showed that structural material selection is driven by building code, cost, and building performance requirements. The environmental performance of the material was not considered. However, once the material was selected, designers tried to maximize environmental performance. The results showed that green building rating systems do not influence structural material selection, and interviewees noted that there is room for improvement in this area. Respondents had a positive view of wood and a strong desire to use more wood, particularly Forest Stewardship Council certified wood. Wood was viewed as the most sustainable structural material available. However, there were some concerns about wood products, with formaldehyde emissions being the most significant.
Dynamic properties of open-grown deciduous trees
Authors: Kane Brian , James Kenneth R.
Published: January 2011

Natural frequency (f) and damping ratio (ζ) are important dynamic parameters that affect the likelihood of tree failure. Much work has investigated these parameters on conifers, but few data exist for open-grown deciduous trees. Considering the risk to people and property from tree failures in residential areas, a better understanding of f and ζ for open-grown deciduous trees is warranted. We measured free vibrations of Bradford pear (Pyrus calleryana Decne. ‘Bradford’) and chestnut oak (Quercus prinus L.) to calculate f and ζ. Subsequently, we remeasured trees after pruning and leaf-drop to investigate the effect of each treatment on f and ζ. While testing one species, an ice storm provided a serendipitous opportunity to investigate the effect of ice accretion on f and ζ. For both species, f did not differ with respect to the cycle for which it was measured or the direction in which the tree swayed. Different types of pruning variably affected f and ζ, but the effect of leaves superseded the effect of pruning, as well as ice accretion. Pruning trees to reduce the likelihood of wind-induced failure may thus be of limited value if significant wind events typically occur when trees are leafless.
Forest management strategies for dealing with fire-related uncertainty when managing two forest seral stages
Authors: Savage David W. , Martell David L. , Wotton B. Mike
Published: January 2011

Ecological values are an important aspect of sustainable forest management, but little attention has been paid to maintaining these values when using traditional linear programming (LP) forest management planning models in uncertain planning environments. We embedded an LP planning model that specifies when and how much to harvest in a simulation model of a “managed” flammable forest landscape. The simulation model was used to evaluate two strategies for dealing with fire-related uncertainty when managing mature and old forest areas. The two seral stage areas were constrained in the LP planning model to a minimum of 10% of the total forest area and the strategies were evaluated under four representative fire regimes. We also developed a risk analysis tool that can be used by forest managers that wish to incorporate fire-related uncertainty in their decision-making. We found that use of the LP model would reduce the areas of the mature and old forest to their lower bound and fire would further reduce the seral areas below those levels, particularly when the mean annual burn fraction exceeds 0.45% per annum. Increasing the minimum area required (i.e., the right-hand side of the constraint) would increase the likelihood of satisfying the minimum area requirements.
Regeneration of Mediterranean Pinus sylvestris under two alternative shelterwood systems within a multiscale framework
Authors: Barbeito Ignacio , LeMay Valerie , Calama Rafael , Cañellas Isabel
Published: January 2011

The inability to obtain sufficient numbers of naturally regenerated trees following partial harvests of some Mediterranean Basin managed forests has prompted the need to critically assess common silvicultural practices. In this study, we examined Scots pine ( Pinus sylvestris L.) regeneration patterns under two shelterwood systems using a multiscale framework. The uniform shelterwood (US) system includes heavier and less frequent timber extractions than the group shelterwood (GS) system. Removal of competing vegetation to expose mineral soil (soil preparation) is sometimes used for US but is not commonly needed in GS. A generalized linear model was used to predict regeneration density for each shelterwood system using environmental variables at microsite- and forest-level scales, medium-scale overstory tree characteristics, and spatial metrics that represent a range of spatial scales. Although US had a higher mean regeneration density, GS had a wider range of regeneration ages. The results derived from this study suggest that ground-level disturbance to break up the herb or organic layer may be required for regeneration establishment. This may occur during repeated partial harvests; otherwise, soil preparation may be required. Overall, this multiscale framework approach resulted in improved predictions and a better understanding of regeneration processes.
MODELING DIFFUSION IN A SIGNAL TRANSDUCTION PATHWAY: THE USE OF VIRTUAL VOLUMES IN P SYSTEMS
Authors: BESOZZI DANIELA , CAZZANIGA PAOLO , COCOLO STEFANIA , MAURI GIANCARLO , PESCINI DARIO
Published: January 2011

In living cells, the diffusion of molecules is fundamental for the proper functioning of many intracellular processes and for their correct response to external or internal signaling. In this paper, we consider the diffusion of a pivotal protein involved in bacterial chemotaxis, and show how to model and simulate the formation of concentration gradients of this protein along the bacterial cell. For this purpose, we exploit the framework of P systems to represent the partition of the bacterial volume into separate but communicating virtual volumes, and make use of communication rules to mimic the diffusive events. We simulate this system by means of the multivolume stochastic simulation algorithm τ-DPP, and present the effects of different diffusion coefficients and of a varying number of virtual volumes over the response of the chemotactic pathway.
A SIMULATION ALGORITHM FOR MULTIENVIRONMENT PROBABILISTIC P SYSTEMS: A FORMAL VERIFICATION
Authors: MARTÍNEZ-DEL-AMOR M. A. , PÉREZ-HURTADO I. , PÉREZ-JIMÉNEZ M. J. , RISCOS-NÚÑEZ A. , SANCHO-CAPARRINI F.
Published: January 2011

Multienvironment probabilistic P systems provide a framework of specification for modeling population biology. It has been used to model real ecosystems in a comprehensible, modular and probabilistic way. However, simulators are needed for virtual experimentation. Hence, the development of correct simulation algorithms becomes a critical point. In this paper we present a formal verification of a new algorithm of simulation designed for this kind of probabilistic P systems.
PC GRAMMAR SYSTEMS WITH CLUSTERS OF COMPONENTS
Authors: CSUHAJ-VARJÚ ERZSÉBET , OSWALD MARION , VASZIL GYÖRGY
Published: January 2011

We introduce PC grammar systems where the components form clusters and the query symbols refer to clusters not individual grammars, i.e., the addressee of the query is not precisely identified. We prove that if the same component replies to all queries issued to a cluster in a rewriting step, then non-returning PC grammar systems with 3 clusters and 7 context-free components are able to generate any recursively enumerable language. We also provide open problems and directions for future research.
ON THE NUMBER OF ACTIVE SYMBOLS IN LINDENMAYER SYSTEMS
Authors: DASSOW JÜRGEN , VASZIL GYÖRGY
Published: January 2011

A symbol a is called active in an L system G if there is a rule a → υ with a ≠ υ in some table of G. By AcX(L) we denote the number of active symbols necessary to generate L by L systems of type X. For two types X and Y of L systems such that the corresponding languages families [Formula: see text] and [Formula: see text] satisfy [Formula: see text], we say that Y is more efficient than X, if there is a sequence of languages [Formula: see text], n ≥ 1, such that AcX(Ln) ≥ n and AcY(Ln) ≤ k for some constant k. In this paper we shall show that the inclusion [Formula: see text] implies that Y is more efficient than X. Analogous results are presented for some modifications of the measure of active symbols.
MORPHIC CHARACTERIZATIONS OF LANGUAGE FAMILIES IN TERMS OF INSERTION SYSTEMS AND STAR LANGUAGES
Authors: OKUBO FUMIYA , YOKOMORI TAKASHI
Published: January 2011

Insertion systems have a unique feature in that only string insertions are allowed, which is in marked contrast to a variety of the conventional computing devices based on string rewriting. This paper will mainly focus on those systems whose insertion operations are performed in a context-free fashion, called context-free insertion systems, and obtain several characterizations of language families with the help of other primitive languages (like star languages) as well as simple operations (like projections, weak-codings). For each k ≥ 1, a language L is a k-star language if L = F+ for some finite set F with the length of each string in F is no more than k. The results of this kind have already been presented in [10] by Păun et al., while the purpose of this paper is to prove enhanced versions of them.

Specifically, we show that each context-free language L can be represented in the form L = h(L(γ)∩F+), where γ is an insertion system of weight (3, 0) (at most three symbols are inserted in a context-free manner), h is a projection, and F+ is a 2-star language. A similar characterization can be obtained for recursively enumerable languages, where insertion systems of weight (3, 3) and 2-star languages are involved.
Single Source Heterojunction Metal–Oxide–Semiconductor Transistors for Quasi-Ballistic Devices: Optimization of Source Heterostructures and Electron Velocity Characteristics at Low Temperature
Authors: Mizuno Tomohisa , Moriyama Yoshihiko , Tezuka Tsutomu , Sugiyama Naoharu , Takagi Shin-ichi
Published: January 2011

We have experimentally studied the electron velocity behavior of single source heterojunction metal–oxide–semiconductor field-effect transistor (SHOTs) without a drain energy spike fabricated by optimizing the source heterostructures. The electron velocity v
E of SHOTs with source conduction band offset ΔE
C strongly depends on the source heterojunction position, and the enhancement of v
E for SHOTs relative to that for single drain-heterojunction transistors (DHOTs) and strained-Si-on-insulator devices (SSOIs) slightly increases with decreasing lattice temperature T. We have also found that v
E for SHOTs, DHOTs, and SSOIs has a power law dependence on low-field electron mobility µEFF, that is, the mean free path of electrons λ at various T. Thus, the electron kinetic energy ΔE
K converted by the source band offset in SHOTs increases with increasing mean free path of electrons at lower T. Using v
E∝λα (α: constant), we can also estimate v
E for both SHOTs and DHOTs at the ballistic transport limit.
Physical Origin of Drive Current Enhancement in Ultrathin Ge-on-Insulator n-Channel Metal–Oxide–Semiconductor Field-Effect Transistors under Full Ballistic Transport
Authors: Takagi Shinichi , Takenaka Mitsuru
Published: January 2011

Drive current (I
sat) of ultrathin germanium-on-insulator (GOI) n-channel metal–oxide–semiconductor field-effect transistors (n-MOSFETs) under full ballistic transport is theoretically investigated for (100)-, (110)-, and (111)-oriented Ge surfaces. The physical origin of the current drive enhancement associated with thinning GOI films for each surface orientation is clarified from the viewpoints of injection velocity (v
inj) and inversion-layer capacitance (C
inv). It is found that v
inj on (111) is significantly enhanced with decreasing the GOI thickness (T
GOI), while no enhancement is observed for (100). This increase in v
inj on (111) originates in the increase in the electron occupancy of the lowest subband due to the size effect of ultrathin GOI films. On the other hand, C
inv on (111) slightly decreases with a decrease in T
GOI, because of the stronger influence of C
inv due to the density-of-states. In contrast, C
inv on (100) significantly increases with a decrease in T
GOI, because of the increase in C
inv due to the inversion-layer thickness, determined by the GOI physical thickness. The (110) GOI surface is found to have intermediate characters between (100) and (111). When I
sat is compared under a given gate voltage, the optimum surface orientation is dependent on T
GOI and gate oxide thickness (T
ox), because of the trade-off relationship in the effective mass between v
inj and C
inv. In bulk Ge and GOI with T
GOI thicker than around 5 nm, (111) and (110) surfaces can provide the identical and maximum I
sat independent of T
ox, which is attributed to the higher v
inj. In GOI with T
GOI thinner than around 5 nm, I
sat is higher in the order of (111), (110), and (100) for T
ox thicker than around 1 nm, while in the order of (110), (100), and (111) in T
GOI thinner than around 1 nm, because of the lowest C
inv on (111). Here, the transition T
ox is dependent on T
GOI. As a consequence, we can conclude that, in a realistic choice of T
GOI and T
ox, (111) and (110) surfaces can yield higher I
sat in GOI n-MOSFETs.
Conduction Mechanism and Low Frequency Noise Analysis in Al/Pr0.7Ca0.3MnO3 for Bipolar Resistive Switching
Authors: Lee Myoung-Sun , Lee Jung-Kyu , Hwang Hyun-Sang , Shin Hyung-Cheol , Park Byung-Gook , Park Young-June , Lee Jong-Ho
Published: January 2011

The low-frequency noise (LFN) Characteristics of bipolar switching devices consisting of Pt (top)/Al/Pr0.7Ca0.3MnO3 (PCMO)/Pt (bottom) were investigated. The noise spectral density in a low frequency range showed a classical 1/f dependence in both high-resistance state (HRS) and low-resistance state (LRS). The random telegraph noise (RTN) were observed in both HRS and LRS which is due to the AlO
x
layer acting as traps at the interface between Al and PCMO or traps in PCMO bulk layer. The voltage dependence of the normalized low-frequency spectral density of current fluctuations (S
i/I
2) presents that the noise properties can be useful indicators to explain the switching mechanism of Al/PCMO device but new noise models should be suggested for the clear approach to analysis of the conduction characteristics in the devices.
Degradation of Poly(3-hexylthiophene):Methano-Fullerene [6,6]-Phenyl-C71 Butyric Acid Methyl Ester Bulk Heterojunction Solar Cells and Annealing Effect on the Degraded Devices
Authors: Lee Yeon-Il , Youn Jun-Ho , Ryu Mi-Sun , Kim Jungho , Jang Jin , Moon Hie-Tae
Published: January 2011

We have studied the degradation of poly(3-hexylthiophene):methano-fullerene [6,6]-phenyl-C71 butyric acid methyl ester (P3HT:PC71BM) bulk heterojunction BHJ solar cells and the annealing effect on the degraded devices. Firstly, the modification of electrical properties of the BHJ solar cells was monitored as a function of illumination time. The degradation of BHJ solar cell is dominated by the filling factor reduction and an irradiation to the solar cell accelerates the gradual degradation. Secondly, we found that inserting LiF between Al cathode and active layer, alleviating degradation, improves the device properties of the solar cell as well as its stability. Moreover, annealing on the degraded device helps partially recover the properties of the solar cell and the diode function. We speculated that this partial recovery caused by annealing is attributed to the rearrangement of P3HT as well as the aggregation of PC71BM.
Effects of Annealing and Atomic Hydrogen Treatment on Aluminum Oxide Passivation Layers for Crystalline Silicon Solar Cells
Authors: Irikawa Junpei , Miyajima Shinsuke , Kida Shuhei , Watahiki Tatsuro , Konagai Makoto
Published: January 2011

The effects of annealing and atomic hydrogen treatment (AHT) on the interface between hydrogenated aluminum oxide (a-Al1-xOx:H) and crystalline silicon (c-Si) were investigated. The annealing increased the negative interface fixed charge density (Qf) from -4.0×1011to -3.0×1012cm-2, whereas AHT reducedQffrom -3.0×1012to 8.3×1011cm-2. Chemical composition analyses revealed the existence of a hydrogenated silicon oxide (a-Si1-xOx:H) interfacial layer. It was also found that annealing and AHT strongly affected the chemical compositions near the interfacial layer. The change inQfis probably caused by the reaction at the interface between the a-Al1-xOx:H and a-Si1-xOx:H.
Influence of γ-Radiation Dose Growth and Dose Rates on Luminescence Properties of Pure Silica Core Fibers with High-OH Group Content
Authors: Ashurov Mukhsin , Baydjanov Maksudbek , Gasanov Eldar , Nuritdinov Izzatillo , Shikama Tatsuo , Salikhbayev Umar
Published: January 2011

Luminescence properties of pure silica core optical fibers (OFs) with a high-OH group content are studied in the visible region at different doses and dose rates of 60Co γ-radiation. It is shown that the γ-induced light emission (GLE) spectra consist of Cherenkov emission along the luminescence bands. Different increase rates of the luminescence bands at 450 and 650 nm and the absorption band at 610 nm with increasing γ-radiation dose are observed. The 450 nm luminescence band is caused by the recombination of holes with the trapped electrons of E'-centers. The dose dependence of the 650 nm luminescence band, caused by the nonbridging oxygen hole center (NBOHC), does not coincide with that of the 610 nm absorption band related to this center. It is shown that a considerable part of NBOHC participates in nonradiative relaxation. Also, there is an absorption band caused by color centers different from NBOHC, that contributes to the formation of the 610 nm absorption band. A linear dependence of GLE intensity (at wavelengths of 450 and 650 nm) on the dose rate increase is observed. Such a dependence is caused by a substantial increase in the Cherenkov emission intensity and comparatively small increases in luminescence band intensities at 450 and 650 nm.
Formation of Columnar-Shaped Structure of Fe in Fe–Cr–Sn Thin Films and Its Shape-Magnetic Anisotropy
Authors: Ichitsubo Tetsu , Uchihara Takeshi , Matsubara Eiichiro , Tsukimoto Susumu , Tamada Yoshinori , Ono Teruo
Published: January 2011

In this work studied has been the fabrication method of columnar-structured Fe thin film for manifestation of a shape anisotropy in Fe–Cr alloy system, in which the phase separation occurs naturally by the thermal treatment. In order to obtain such a columnar structure, we have utilized the phase separation on a Sn-nanoparticle-dispersed Si substrate, by exploiting an excellent metallurgical affinity of Fe and Sn, and moreover we have employed applying an external magnetic field. Resultingly, we have found that the columnar-structured Fe thin films are likely to be formed after annealing. Thus obtained Fe–Cr–Sn thin film was found to exhibit a high shape-magnetic anisotropy, where the out-of-plane coercivity H
c⊥ was about 750 Oe, being five times larger than the in-plane coercivity H
c||
of about 150 Oe.