bluuebunny/crossref_metadata_2025 huggingface dataset:
Promoting recovery: service user and staff perceptions of resilience provided by a new Early Intervention in Psychosis service
Authors: Morton Adrian , Fairhurst Alicia , Ryan Rebecca
Published: January 2010

Aim: The principles and practice of recovery are guiding many changes in mental health service provision. As a new Early Intervention in Psychosis (EIP) service, we were interested in finding out if both staff and users perceive the service as promoting resilience and in turn, recovery.

Methods: A naturalistic sample of service users and staff completed the Organizational Climate questionnaire to assess the degree to which the service promotes resilience in overcoming a first episode psychosis.

Results: The results indicated that both staff and service users similarly perceive the service as positively supporting resilience. The one exception was the staff rated the ‘available resources to meet people's needs’ as less than service users.

Conclusions: The positive rating of resilience indicated that the service is working in a manner consistent with a recovery orientation. The results will act as a benchmark to compare with both other EIP services and future performance.
Paliperidone extended‐release tablets in patients with recently diagnosed schizophrenia
Authors: Canuso Carla M. , Bossie Cynthia A. , Amatniek Joan , Turkoz Ibrahim , Pandina Gahan , Cornblatt Barbara
Published: January 2010

Aim: Effective early and persistent antipsychotic treatment in recently diagnosed schizophrenia may positively impact long‐term outcomes. Paliperidone extended‐release (ER) was assessed in this population.

Methods: Post hoc analysis of pooled data from three 6‐week, double‐blind (DB), placebo‐controlled, and three 1‐year open‐label (OL) studies of paliperidone ER in schizophrenia patients. Data stratified by time since diagnosis (≤3 vs. >3 years).

Results: At DB (n = 1193) and OL baselines (n = 744), 259 (21.9%) and 188 (25.3%) patients were diagnosed ≤3 years. At DB end point, both populations improved with paliperidone ER versus placebo on Positive and Negative Syndrome Scale (PANSS) total, Clinical Global Impressions–Severity and Personal and Social Performance (PSP) scale scores (all P < 0.05). At OL end point, there were significant improvements from DB baseline in both populations on these scales (P < 0.0001), with greater improvement in the ≤3‐year population on PANSS total (P < 0.001) and PSP (P < 0.001) scores. During DB treatment, only the ≤3‐year population reported adverse events (AEs) in ≥5% (placebo‐adjusted rate) of subjects receiving paliperidone ER: akathisia, extrapyramidal disorder not otherwise specified and somnolence. During OL treatment, akathisia and somnolence occurred more frequently (≥5%) in the ≤3‐ versus >3‐year population. OL study completion rates were 51.1% in ≤3‐year, and 48.2% in >3‐year subjects.

Conclusions: Paliperidone ER significantly improved symptoms and functioning in schizophrenia patients, regardless of time since diagnosis. Recently diagnosed patients who continued treatment exhibited greater symptom reduction and functional benefit over the long term. Results also suggest that these patients may be more susceptible to certain AEs.
Water‐Quality Performance of a Constructed Stormwater Wetland for All Flow Conditions1
Authors: Wadzuk Bridget M. , Rea Matthew , Woodruff Gregg , Flynn Kelly , Traver Robert G.
Published: January 2010

Wadzuk, Bridget M., Matthew Rea, Gregg Woodruff, Kelly Flynn, and Robert G. Traver, 2010. Water‐Quality Performance of a Constructed Stormwater Wetland for All Flow Conditions. Journal of the American Water Resources Association (JAWRA) 46(2):385‐394. DOI: 10.1111/j.1752‐1688.2009.00408.x

Abstract:  Results from a multiyear study demonstrate that a constructed stormwater wetland (CSW) improves urban stormwater runoff quality mitigating downstream impacts. Best management practices, such as CSWs, can comprehensively treat the various scales of stormwater runoff issues. Discrete sample analysis was used to investigate the CSW effect for storm events and base‐flow periods on water‐quality parameters [i.e., total suspended solids, total dissolved solids, total nitrogen, phosphorous (total and reactive), chloride, heavy metals (zinc, lead, and copper), and Escherichia coli]. The primary finding was that stormwater sediment load was removed through the CSW for all flow conditions during all seasons. The mechanisms responsible for the removal of suspended solids, including slower flow velocity, longer retention times, and vegetative contact, also reduced the mass of nutrients discharged downstream throughout the year. Exceedance probabilities were used to evaluate the expected pollutant reductions of nutrients and to incorporate the effect of natural flow variation on quality. Other findings included the observation that there was no significant difference in the performance of the CSW over two‐year‐long periods four years apart, indicating that a CSW is effective for an extended period.
Stream Condition in Piedmont Streams with Restored Riparian Buffers in the Chesapeake Bay Watershed1
Authors: Orzetti Leslie L. , Jones R. Christian , Murphy Robert F.
Published: January 2010

Orzetti, Leslie L., R. Christian Jones, and Robert F. Murphy, 2010. Stream Condition in Piedmont Streams with Restored Riparian Buffers in the Chesapeake Bay Watershed. Journal of the American Water Resources Association (JAWRA) 46(3):473‐485. DOI: 10.1111/j.1752‐1688.2009.00414.x

Abstract:  This study tested the efficacy of restored forest riparian buffers along streams in the Chesapeake Bay watershed by examining habitat, selected water quality variables, and benthic macroinvertebrate community metrics in 30 streams with buffers ranging from zero to greater than 50 years of age. To assess water quality we measured in situ parameters (temperature, dissolved oxygen, and conductivity) and laboratory‐analyzed grab samples (soluble reactive phosphorus, total phosphorus, nitrate, ammonium, and total suspended solids). Habitat conditions were scored using the Environmental Protection Agency Rapid Bioassessment Protocols for high gradient streams. Benthic macroinvertebrates were quantified using pooled riffle/run kick samples. Results showed that habitat, water quality, and benthic macroinvertebrate metrics generally improved with age of restored buffer. Habitat scores appeared to stabilize between 10 and 15 years of age and were driven mostly by epifaunal substrate availability, sinuosity, embeddedness, and velocity depth regime. Benthic invertebrate taxa richness, percent Ephemeroptera, Plecoptera, Trichoptera minus hydropsychids (%EPT minus H), % Ephemeroptera, and the Family Biotic Index were among the metrics which improved with age of buffer zone. Results are consistent with the hypothesis that forest riparian buffers enhance instream habitat, water quality, and resulting benthic macroinvertebrate communities with noticeable improvements occurring within 5‐10 years postrestoration, leading to conditions approaching those of long established buffers within 10‐15 years of restoration.
Correlative and mechanistic models of species distribution provide congruent forecasts under climate change
Authors: Kearney Michael R. , Wintle Brendan A. , Porter Warren P.
Published: January 2010

Good forecasts of climate change impacts on extinction risks are critical for effective conservation management responses. Species distribution models (SDMs) are central to extinction risk analyses. The reliability of predictions of SDMs has been questioned because models often lack a mechanistic underpinning and rely on assumptions that are untenable under climate change. We show how integrating predictions from fundamentally different modeling strategies produces robust forecasts of climate change impacts on habitat and population parameters. We illustrate the principle by applying mechanistic (Niche Mapper) and correlative (Maxent, Bioclim) SDMs to predict current and future distributions and fertility of an Australian gliding possum. The two approaches make congruent, accurate predictions of current distribution and similar, dire predictions about the impact of a warming scenario, supporting previous correlative‐only predictions for similar species. We argue that convergent lines of independent evidence provide a robust basis for predicting and managing extinctions risks under climate change.
Making Markets for Merit Goods: The Political Economy of Antiretrovirals
Authors: Kapstein Ethan B. , Busby Joshua W.
Published: January 2010

Why were AIDS activists successful in putting universal access to treatment on the international agenda when so many other global campaigns have either failed or struggled to have much impact? We focus on: (1) permissive material conditions; (2) convergence on a policy prescription; (3) attributes of the activists; and (4) the broad political support for their cause. In our view, the market for antiretroviral (ARV) drugs was politically constructed; activists had to bring the demand and supply sides of the market together through a variety of tactics and strategies. The idea that motivated the activists was that ARVs should ideally be ‘merit goods’, goods that are available to everyone regardless of income. But, when ARVs first came on the market, poor people in the developing world lacked the resources to buy them. Activists successfully lobbied donor nations to use foreign aid to buy ARVs, and they pressured pharmaceutical companies to lower their prices, while encouraging generic firms to enter the market. However, even where a policy enjoys favorable material conditions – i.e. low costs, large benefits, demonstrated feasibility – this may not be enough. A clear prescription, credible messengers and resonant arguments may be necessary for an issue to receive adequate political support.

Policy Implications

Global activists are playing an increasingly important role in world politics, but global activism influences policy outcomes only under certain conditions.

Global activists can only succeed when they couple compelling moral arguments with permissive material conditions.

Global activists need to build broad coalitions in order to be politically successful.

Despite the success of the access to treatment regime, questions remain about its sustainability in light of the great recession that began in 2008, donor fatigue regarding AIDS and the emergence of other policy priorities in the foreign aid community.
Global Governance after the Financial Crisis: A New Multilateralism or the Last Gasp of the Great Powers?
Authors: Woods Ngaire
Published: January 2010

In the wake of the global financial crisis, three G20 Summits have reinvigorated global cooperation, thrusting the International Monetary Fund centre stage with approximately $1 trillion of resources. With China, Brazil, India, Russia and other powerful emerging economies now at the table, is a new more multilateral era of governance emerging? This article examines the evidence. It details the governance reforms and new financing of the IMF but finds only very limited shifts in the engagement of major emerging economies – insufficient to position the IMF to address the global imbalances, to set new multilateral rules, to operate as an alternative to self‐insurance or indeed to provide a more multilateral response to the development emergency. The IMF is shifting between: borrower dependence (relying on fee‐paying borrowers for income); independence (with its own investment income); and lender dependence (relying on wealthy members to extend credit lines to it). The result is an ambiguous set of forces restraining the IMF to stay as it is, and only weakly driving reform. A new order may emerge in which multilateral institutions – such as the IMF – end up with only a limited role to play alongside emerging national and regional strategies, unless a more radical transformation begins.

Policy Implications

 IMF governance (decision‐making majority, location, management and staffing) needs to transform fast if it is to address the tasks assigned to it by the G20.

 The IMF’s dependence on loans from its wealthiest members (for its new $600 billion) restrains the institution from serious reform, only weakly offering a driver for further change.

 There has been a failure to mandate and resource the IMF (and its sister institution the World Bank) so as to ensure a multilateral response to the ‘development emergency’ that has resulted from the financial crisis.
Thermohydrodynamic Analysis of Bump Type Gas Foil Bearings: A Model Anchored to Test Data
Authors: San Andrés Luis , Kim Tae Ho
Published: January 2010

The paper introduces a thermohydrodynamic (THD) model for prediction of gas foil bearing (GFB) performance. The model includes thermal energy transport in the gas film region and with cooling gas streams, inner or outer, as in typical rotor-GFBs systems. The analysis also accounts for material property changes and the bearing components’ expansion due to temperature increases and shaft centrifugal growth due to rotational speed. Gas inlet feed characteristics are thoroughly discussed in bearings whose top foil must detach, i.e., not allowing for subambient pressure. Thermal growths determine the actual bearing clearance needed for accurate prediction of GFB forced performance, static and dynamic. Model predictions are benchmarked against published measurements of (metal) temperatures in a GFB operating without a forced cooling gas flow. The tested foil bearing is proprietary; hence, its geometry and material properties are largely unknown. Predictions are obtained for an assumed bearing configuration, with bump-foil geometry and materials taken from prior art and best known practices. The predicted film peak temperature occurs just downstream of the maximum gas pressure. The film temperature is higher at the bearing middle plane than at the foil edges, as the test results also show. The journal speed, rather than the applied static load, influences more the increase in film temperature and with a larger thermal gradient toward the bearing sides. In addition, as in the tests conducted at a constant rotor speed and even for the lowest static load, the gas film temperature increases rapidly due to the absence of a forced cooling air that could carry away the recirculation gas flow and thermal energy drawn by the spinning rotor; predictions are in good agreement with the test data. A comparison of predicted static load parameters to those obtained from an isothermal condition shows the THD model producing a smaller journal eccentricity (larger minimum film thickness) and larger drag torque. An increase in gas temperature is tantamount to an increase in gas viscosity, hence, the noted effect in the foil bearing forced performance.
Experimental Analysis of a Waveguide Pressure Measuring System
Authors: White Matthew A. , Dhingra Manuj , Prasad J. V. R.
Published: January 2010

An infinite-line probe is commonly used to measure unsteady pressure in high-temperature environments while protecting the pressure transducer. In this study, an existing theoretical model is used to derive the response of a waveguide pressure measuring system. An ambient temperature centrifugal compressor rig acts as an experimental source of fluctuating pressure. The compressor is operated at different discrete rotational speeds, and the blade-passing frequencies are used to obtain frequency response data. In the experiments, pressure waves attenuated at a rate faster than that predicted by the theoretical model for a 0.322 m (12 in.) sensor offset. Furthermore, the decay in the magnitude of the pressure oscillations accelerated at blade-passing frequencies above 9 kHz. A unique contribution of this study is to show that whereas the experimentally observed overall attenuation is broadly consistent with the theoretical predictions, pressure oscillations corresponding to individual blade passages may be disproportionally attenuated.
Investigation of Nozzle Flow and Cavitation Characteristics in a Diesel Injector
Authors: Som S. , Aggarwal S. K. , El-Hannouny E. M. , Longman D. E.
Published: January 2010

Cavitation and turbulence inside a diesel injector play a critical role in primary spray breakup and development processes. The study of cavitation in realistic injectors is challenging, both theoretically and experimentally, since the associated two-phase flow field is turbulent and highly complex, characterized by large pressure gradients and small orifice geometries. We report herein a computational investigation of the internal nozzle flow and cavitation characteristics in a diesel injector. A mixture based model in FLUENT V6.2 software is employed for simulations. In addition, a new criterion for cavitation inception based on the total stress is implemented, and its effectiveness in predicting cavitation is evaluated. Results indicate that under realistic diesel engine conditions, cavitation patterns inside the orifice are influenced by the new cavitation criterion. Simulations are validated using the available two-phase nozzle flow data and the rate of injection measurements at various injection pressures (800–1600 bar) from the present study. The computational model is then used to characterize the effects of important injector parameters on the internal nozzle flow and cavitation behavior, as well as on flow properties at the nozzle exit. The parameters include injection pressure, needle lift position, and fuel type. The propensity of cavitation for different on-fleet diesel fuels is compared with that for n-dodecane, a diesel fuel surrogate. Results indicate that the cavitation characteristics of n-dodecane are significantly different from those of the other three fuels investigated. The effect of needle movement on cavitation is investigated by performing simulations at different needle lift positions. Cavitation patterns are seen to shift dramatically as the needle lift position is changed during an injection event. The region of significant cavitation shifts from top of the orifice to bottom of the orifice as the needle position is changed from fully open (0.275 mm) to nearly closed (0.1 mm), and this behavior can be attributed to the effect of needle position on flow patterns upstream of the orifice. The results demonstrate the capability of the cavitation model to predict cavitating nozzle flows in realistic diesel injectors and provide boundary conditions, in terms of vapor fraction, velocity, and turbulence parameters at the nozzle exit, which can be coupled with the primary breakup simulation.
Engine Emission Modeling Using a Mixed Physics and Regression Approach
Authors: Benz Michael , Onder Christopher H. , Guzzella Lino
Published: January 2010

This paper presents a novel control-oriented model of the raw emissions of diesel engines. An extended quasistationary approach is developed where some engine process variables, such as combustion or cylinder charge characteristics, are used as inputs. These inputs are chosen by a selection algorithm that is based on genetic-programming techniques. Based on the selected inputs, a hybrid symbolic regression algorithm generates the adequate nonlinear structure of the emission model. With this approach, the model identification efforts can be reduced significantly. Although this symbolic regression model requires fewer than eight parameters to be identified, it provides results comparable to those obtained with artificial neural networks. The symbolic regression model is capable of predicting the behavior of the engine in operating points not used for the model parametrization, and it can be adapted easily to other engine classes. Results from experiments under steady-state and transient operating conditions are used to show the accuracy of the presented model. Possible applications of this model are the optimization of the engine system operation strategy and the derivation of virtual sensor designs.
Characterization of Forced Flame Response of Swirl-Stabilized Turbulent Lean-Premixed Flames in a Gas Turbine Combustor
Authors: Kim Kyu Tae , Lee Jong Guen , Lee Hyung Ju , Quay Bryan D. , Santavicca Domenic A.
Published: January 2010

Flame transfer function measurements of turbulent premixed flames are made in a model lean-premixed, swirl-stabilized, gas turbine combustor. OH∗, CH∗, and CO2∗ chemiluminescence emissions are measured to determine heat release oscillation from a whole flame, and the two-microphone technique is used to measure inlet velocity fluctuation. 2D CH∗ chemiluminescence imaging is used to characterize the flame shape: the flame length (LCH∗ max) and flame angle (α). Using H2-natural gas composite fuels, XH2=0.00–0.60, a very short flame is obtained and hydrogen enrichment of natural gas is found to have a significant impact on the flame structure and flame attachment points. For a pure natural gas flame, the flames exhibit a “V” structure, whereas H2-enriched natural gas flames have an “M” structure. Results show that the gain of M flames is much smaller than that of V flames. Similar to results of analytic and experimental investigations on the flame transfer function of laminar premixed flames, it shows that the dynamics of a turbulent premixed flame is governed by three relevant parameters: the Strouhal number (St=LCH∗ max/Lconv), the flame length (LCH∗ max), and the flame angle (α). Two flames with the same flame shape exhibit very similar forced responses, regardless of their inlet flow conditions. This is significant because the forced flame response of a highly turbulent, practical gas turbine combustor can be quantitatively generalized using the nondimensional parameters, which collapse all relevant input conditions into the flame shape and the Strouhal number.
Testing and Calibration Procedures for Mistuning Identification and Traveling Wave Excitation of Blisks
Authors: Holland Darren E. , Castanier Matthew P. , Ceccio Steven L. , Epureanu Bogdan I. , Filippi Sergio
Published: January 2010

In this work, an integrated testing and calibration procedure is presented for performing mistuning identification (ID) and traveling wave excitation (TWE) of one-piece bladed disks (blisks). The procedure yields accurate results while also being highly efficient and is comprised of three basic phases. First, selected modes from a tuned blisk finite element model are used to determine a minimal set of measurement degrees of freedom (and locations) that will work well for mistuning ID. Second, a testing procedure is presented that allows the mistuning to be identified from relatively few vibration response measurements. A numerical validation is used to investigate the convergence of the mistuning ID results to a prescribed mistuning pattern using the proposed approach and alternative testing strategies. Third, a method is derived to iteratively calibrate the excitation applied to each blade so that differences among the blade excitation magnitudes can be minimized for a single blade excitation, and also the excitation phases can be accurately set to achieve the desired traveling wave excitation. The calibration algorithm uses the principle of reciprocity and involves solving a least-squares problem to reduce the effects of measurement noise and uncertainty. Because the TWE calibration procedure re-uses the data collected during the mistuning ID, the overall procedure is integrated and efficient.
Combustion Characteristics of HCCI in Motorcycle Engine
Authors: Wu Yuh-Yih , Jang Ching-Tzan , Chen Bo-Liang
Published: January 2010

Homogeneous charge compression ignition (HCCI) is recognized as an advanced combustion system for internal combustion engines that reduces fuel consumption and exhaust emissions. This work studied a 150 cc air-cooled, four-stroke motorcycle engine employing HCCI combustion. The compression ratio was increased from 10.5 to 12.4 by modifying the cylinder head. Kerosene fuel was used without intake air heating and operated at various excess air ratios (λ), engine speeds, and exhaust gas recirculation (EGR) rates. Combustion characteristics and emissions on the target engine were measured. It was found that keeping the cylinder head temperature at around 120–130°C is important for conducting a stable experiment. Two-stage ignition was observed from the heat release rate curve, which was calculated from cylinder pressure. Higher λ or EGR causes lower peak pressure, lower maximum rate of pressure rise (MRPR), and higher emission of CO. However, EGR is better than λ for decreasing the peak pressure and MRPR without deteriorating the engine output. Advancing the timing of peak pressure causes high peak pressure, and hence increases MRPR. The timing of peak pressure around 10–15 degree of crank angle after top dead center indicates a good appearance for low MRPR.
Tribological and mechanical properties of nanocrystalline-TiC/a-C nanocomposite thin films
Authors: Musil J. , Novák P. , Čerstvý R. , Soukup Z.
Published: January 2010

This article reports on interrelationships between x-ray structure, mechanical properties, coefficient of friction μ, and wear coefficient k of ∼3000 m thick nc-TiC/a-C nanocomposite films sputtered using unbalanced magnetron from a composed C/Ti target (∅=100 mm); here nc and a denotes the nanocrystalline and amorphous phase, respectively. It is shown that (1) μ and k of the nc-TiC/a-C nanocomposite film strongly depend not only on its hardness H but also on its effective Young’s modulus E∗=E/(1−ν2); here ν is the Poisson s ratio, (2) the nc-TiC/a-C nanocomposite films with C/Ti>1.5 and the ratio H3/E∗2 (characterizing the resistance of film to plastic deformation) ranging from ∼0.2 to ∼0.3 exhibit the lowest values of μ and k, and (3) μ increases with increasing load L of the testing ball. The main result of this investigation is the finding that the achievement of the lowest value E∗ at a given value of H is of key importance in the formation of films with the lowest values of coefficient of friction μ and wear coefficient k.
Transforming Medicine via Digital Innovation
Authors: Topol Eric J.
Published: January 2010

The newfound ability to monitor physiological
metrics digitally via non-invasive wireless sensors, along with genome-wide
scanning and whole-genome sequencing, should lead to an extraordinary
accrual of physiological and biological data about individuals.
The fermentable fibre inulin increases postprandial serum short-chain fatty acids and reduces free-fatty acids and ghrelin in healthy subjects
Authors: Tarini Joshua , Wolever Thomas M.S.
Published: January 2010

It is thought that diets high in dietary fibre are associated with reduced risk for type 2 diabetes, at least in part because the short-chain fatty acids (SCFAs) produced during the colonic fermentation of fibre beneficially influence circulating concentrations of free-fatty acids (FFAs) and gut hormones involved in the regulation of blood glucose and body mass. However, there is a paucity of data showing this sequence of events in humans. Thus, our objective was to determine the effect of the fermentable fibre inulin on postprandial glucose, insulin, SCFA, FFA, and gut hormone responses in healthy subjects. Overnight fasted healthy subjects (n = 12) were studied for 6 h after consuming 400 mL drinks, containing 80 g high-fructose corn syrup (80HFCS), 56 g HFCS (56HFCS), or 56 g HFCS plus 24 g inulin (Inulin), using a randomized, single-blind, crossover design. A standard lunch was served 4 h after the test drink. Glucose and insulin responses after Inulin did not differ significantly from those after 80HFCS or 56HFCS. Serum acetate, propionate, and butyrate were significantly higher after Inulin than after HFCS drinks from 4–6 h. FFAs fell at a similar rate after all 3 test drinks, but were lower after Inulin than after 56HFCS at 4 h (0.40 ± 0.06 vs. 0.51 ± 0.06 mmol·L–1; p < 0.05). Compared with 56HFCS, Inulin significantly increased plasma glucagon-like peptide-1 concentrations at 30 min, and reduced ghrelin at 4.5 h and 6 h. The results are consistent with the hypothesis that dietary fibre increases the production of colonic SCFAs, which may reduce type 2 diabetes risk by reducing postprandial FFAs and favorably affecting gut hormones, which regulate food intake.
An investigation into the possible physiological mechanisms associated with changes in performance related to acute responses to different preactivity stretch modalities
Authors: Fletcher Iain M. , Monte-Colombo Mathew M.
Published: January 2010

The aim of this study was to explore the potential mechanisms underlying performance changes linked to different warm-up stretch modalities. Twenty-one male collegiate–semiprofessional soccer players (age, 20.8 ±2.3 years) performed under 3 different warm-up conditions: a no-stretch warm-up (WU), a warm-up including static passive stretches (SPS), and a warm-up incorporating static dynamic stretches (SDS). Countermovement jump, drop jump, peak torque, heart rate, core temperature, movement kinematics, and electromyography (EMG) were recorded for each intervention. Significant increases (p < 0.001) in performance were recorded for the countermovement, drop jump, and peak torque measures when the SDS was compared with the WU and SPS trials. When mechanism data were analysed, heart rate was significantly higher (p < 0.001) in the SDS condition compared with the SPS and WU conditions (a pattern also shown with core temperature), whereas the WU condition heart rate was also significantly higher than the SPS condition heart rate. When EMG data were examined for the rectus femoris muscle, significantly greater (p < 0.01) muscle activity was observed in the SDS condition compared with the SPS condition. It seems the most likely mechanisms to explain the increase in performance in the SDS condition compared with the SPS condition are increased heart rate, greater muscle activity, and increased peak torque.
Utilization of positional isotope exchange experiments to evaluate reversibility of ATP hydrolysis catalyzed byEscherichia coliLon proteaseThis paper is one of a selection of papers published in this special issue entitled 8th International Conference on AAA Proteins and has undergone the Journal's usual peer review process.
Authors: Thomas Jennifer , Fishovitz Jennifer , Lee Irene
Published: January 2010

Lon protease, also known as protease La, is an ATP-dependent serine protease. Despite the presence of a proteolytic Ser–Lys dyad, the enzyme only catalyzes protein degradation in the presence of ATP. Lon possesses an intrinsic ATPase activity that is stimulated by protein and certain peptide substrates. Through sequence alignment and analysis, it is concluded that Lon belongs to the AAA+ protein family. Previous kinetic characterization of the ATPase domain of Escherichia coli Lon protease implicates a half-site reactivity model in which only 50% of the ATP bound to Lon are hydrolyzed to yield ADP; the remaining ATPase sites remain bound with ATP and are considered non-catalytic. In this model, it is implied that ATP hydrolysis is irreversible. To further evaluate the proposed half-site reactivity model, the reversibility of the ATPase activity of E. coli Lon was evaluated by positional isotope exchange experiments. The ATPase reactions were conducted in the18O-enriched buffer such that the extent of18O incorporation into inorganic phosphate generated from ATP hydrolysis could be used to evaluate the extent of reversibility in ATP hydrolysis. Collectively, our experimental data reveal that the ATPase reaction catalyzed by E. coli Lon in the presence and absence of peptide substrate that stimulated the enzyme’s ATPase activity is irreversible. Therefore, the half-site ATPase reactivity of E. coli Lon is validated, and can be used to account for the kinetic mechanism of the ATP-dependent peptidase activity of the enzyme.
Towards a unifying mechanism for ClpB/Hsp104-mediated protein disaggregation and prion propagationThis paper is one of a selection of papers published in this special issue entitled 8th International Conference on AAA Proteins and has undergone the Journal's usual peer review process.
Authors: Haslberger Tobias , Bukau Bernd , Mogk Axel
Published: January 2010

The oligomeric AAA+ chaperones ClpB/Hsp104 mediate the reactivation of aggregated proteins, an activity that is crucial for the survival of cells during severe stress. Hsp104 is also essential for the propagation of yeast prions by severing prion fibres. Protein disaggregation depends on the cooperation of ClpB/Hsp104 with a cognate Hsp70 chaperone system. While Hsp70 chaperones are also involved in prion propagation, their precise role is much less well defined compared with its function in aggregate solubilization. Therefore, it remained unclear whether both ClpB/Hsp104 activities are based on common or different mechanisms. Novel data show that ClpB/Hsp104 uses a motor threading activity to remodel both protein aggregates and prion fibrils. Moreover, transfer of both types of substrates to the ClpB/Hsp104 processing pore site requires initial substrate interaction of Hsp70. Together these data emphasize the similarity of thermotolerance and prion propagation pathways and point to a shared mechanistic principle of Hsp70–ClpB/Hsp104-mediated solubilization of amorphous and ordered aggregates.
Silica-bondedS-sulfonic acid as a recyclable catalyst for the silylation of hydroxyl groups with hexamethyldisilazane (HMDS)
Authors: Niknam Khodabakhsh , Saberi Dariush , Molaee Hajar , Zolfigol Mohammad Ali
Published: January 2010

Silica-bonded S-sulfonic acid (SBSSA) was prepared by the reaction of 3-mercaptopropylsilica (MPS) and chlorosulfonic acid in tert-butylmethyl ether, and used as a catalyst for the silylation of hydroxyl groups. A good range of primary, secondary alcohols and phenolic hydroxyl groups were effectively converted into their corresponding trimethylsilyl ethers with hexamethyldisilazane (HMDS) in the presence of catalytic amounts of SBSSA under mild conditions at room temperature with short reaction times and in good-to-excellent yields. An excellent chemoselective silylation of hydroxyl groups in the presence of other functional groups was also observed. The heterogeneous catalyst was recycled for 30 runs upon the reaction of benzyl alcohol with HMDS without lossing its catalytic activity.
Mixed-species effect on tree aboveground carbon pools in the east-central boreal forests
Authors: Cavard Xavier , Bergeron Yves , Chen Han Y.H. , Paré David
Published: January 2010

This study investigates the potential of mixed forest stands as better aboveground carbon sinks than pure stands. According to the facilitation and niche complementarity hypotheses, we predict higher carbon sequestration in mature boreal mixedwoods. Aboveground carbon contents of black spruce ( Picea mariana (Mill.) Britton, Sterns, Poggenb.) and trembling aspen ( Populus tremuloides Michx.) mixtures were investigated in the eastern boreal forest, whereas jack pine ( Pinus banksiana Lamb.) and trembling aspen were used in the central boreal forest. No carbon gain was found in species mixtures; nearly pure trembling aspen stands contained the greatest amount of aboveground carbon, black spruce stands had the least, and mixtures were intermediate with amounts that could generally be predicted by linear interpolation with stem proportions. These results suggest that for aspen, the potentially detrimental effect of spruce on soils observed in other studies may be offset by greater light availability in mixtures. On the other hand, for black spruce, the potentially beneficial effects of aspen on soils could be offset by greater competition by aspen for nutrients and light. The mixture of jack pine and trembling aspen did not benefit any of these species while inducing a loss in trembling aspen carbon at the stand level.
Long-term patterns in the decay, collapse, and abundance of trees with hollows in the mountain ash (Eucalyptus regnans) forests of Victoria, southeastern Australia
Authors: Lindenmayer David B. , Wood Jeff T.
Published: January 2010

Large trees with hollows are an important component of stand structural complexity worldwide. Understanding their population dynamics is needed to manage cavity-dependent biota. We quantified long-term rates of collapse of 302 measured trees with hollows in 1939-aged regrowth mountain ash ( Eucalyptus regnans F. Muell.) forest in southeastern Australia. We identified time-dependent dynamics in which the collapse rates of trees slowed from ∼4% annually between 1983 and 1993 to ∼2.2% between 1993 and 2007. Transitions of trees between different decay states (forms) also slowed over time. Nevertheless, during the 24-year period of our study, over half of our marked and measured trees had fallen, but there was no recruitment of new trees with hollows. Under current projections, few trees with hollows will occur on our field sites by ∼2050, although more had been forecast in earlier investigations. Such a paucity of trees with hollows in extensive areas of regrowth mountain ash forests will lead to a shortage of nesting and sheltering sites for cavity-dependent biota. We suggest a short–medium (10- to 100-year) focus on the conservation of old growth and multi-aged stands will be needed to maintain populations of those species strongly associated with trees with hollows in mountain ash forests.
Linear trend and climate response of five-needle pines in the western United States related to treeline proximity
Authors: Kipfmueller Kurt F. , Salzer Matthew W.
Published: January 2010

Five-needle pines provide some of the world’s longest chronologies of paleoclimate interest. We examined 66 five-needle pine growth chronologies from 1896 to their end years using linear trend, correlation, and cluster analyses. Chronologies were categorized based on the sites’ proximity to upper treeline. A significant positive trend in ring width over the post-1896 interval was most common in upper treeline chronologies, but positive linear trend was found in all elevational proximity classes and all species. Cluster analysis of climate response patterns identified four groups exhibiting strong associations with (i) positive response to previous autumn, winter, and spring precipitation, (ii) positive response to spring and (or) summer precipitation coupled with an inverse relationship with summer temperature, (iii) positive response to winter and (or) spring precipitation coupled with an inverse relationship with spring temperature, and (iv) positive associations with temperature in all seasons except spring and no appreciative precipitation response. Most chronologies positively associated with temperatures were from sites located near upper treeline and also contain significant positive linear trend. Our results suggest that some five-needle pine treeline chronologies may be reliable predictors of past temperatures, but careful site selection is required.
Antidigoxin antiserum prevents endogenous digitalis-like compound-mediated reperfusion injury via modulating sodium pump isoform gene expression
Authors: Wang He-Gui , Chu Yue-Feng , Zou Jian-Gang , Ke Yong-Sheng
Published: January 2010

Endogenous digitalis-like compound (EDLC) is an endogenous ligand of the digitalis receptor and can remarkably inhibit Na+/K+-ATPase activity. Antidigoxin antiserum (ADA), a selective EDLC antagonist, may lessen myocardial reperfusion injury; however, the molecular mechanisms underlying the effect remain unclear. Therefore, this study investigated whether ADA may prevent myocardial reperfusion injury and modulate gene expression of sodium pump α isoforms. Cardiac function was examined in isolated rat hearts subjected to ischemia and reperfusion (I/R). The infarct size, EDLC level, Na+/K+-ATPase activity, and the levels of mRNA for sodium pump α isoforms were measured in vivo I/R rat hearts in the presence or absence of ADA. It was found that ADA significantly improved the recovery of cardiac function, decreased infarct size, decreased EDLC level, and recovered Na+/K+-ATPase activity in I/R hearts. Further studies showed that sodium pump α1, α2, and α3 isoform mRNA levels were significantly reduced in I/R hearts, and pretreatment with ADA induced a large increase in the mRNA levels. These results indicate that EDLC may participate in depressing Na+/K+-ATPase activity and sodium pump α isoform gene expression in I/R heart. It is suggested that treatment with ADA may prevent EDLC-mediated reperfusion injury via modulating sodium pump isoform gene expression.
PATH INTEGRAL QUANTIZATION OF SUPERSTRING
Authors: ELEGLA H. A. , FARAHAT N. I.
Published: January 2010

Motivated by the Hamilton–Jacobi approach of constrained systems, we analyze the classical structure of a four-dimensional superstring. The equations of motion for a singular system are obtained as total differential equations in many variables. The path integral quantization based on Hamilton–Jacobi approach is applied to quantize the system, and the integration is taken over the canonical phase space coordinates.
MOMENTUM MAPS, INDEPENDENT FIRST INTEGRALS AND INTEGRABILITY FOR CENTRAL POTENTIALS
Authors: FIORANI EMANUELE
Published: January 2010

It is shown that all the motions of a natural Hamiltonian H(q, p) = ½‖p‖2+V(q) lie on planes through 0 ∈ Rn if and only if V is a central potential, i.e. H admits SO(n) symmetry. Then, using the momentum maps associated to their natural symmetry groups, we study in detail the functional independence of first integrals of a general central potential, of the isotropic harmonic potential and of the Kepler potential. We show that all the smooth first integral of the isotropic harmonic oscillator are dependent of the angular momentum tensor L and of the Fradkin tensor H, and that all the smooth first integrals of the Kepler system on the region of negative energy are dependent of the angular momentum tensor L and of the Laplace–Runge–Lenz vector B.
AN ELEMENTAL OVERVIEW OF THE NONHOLONOMIC NOETHER THEOREM
Authors: FASSÒ FRANCESCO , SANSONETTO NICOLA
Published: January 2010

Noether theorem plays a central role in linking symmetries and first integrals in Lagrangian mechanics. The situation is different in the nonholonomic context, but in the last decades there have been several extensions of Noether theorem to the nonholonomic setting. We provide an overview of this subject which is as elementary as possible.
DIFFERENTIAL GALOIS THEORY AND INTEGRABILITY
Authors: MACIEJEWSKI ANDRZEJ J. , PRZYBYLSKA MARIA
Published: January 2010

This paper is an overview of our works that are related to investigations of the integrability of natural Hamiltonian systems with homogeneous potentials and Newton's equations with homogeneous velocity independent forces. The two types of integrability obstructions for these systems are presented. The first, local ones, are related to the analysis of the differential Galois group of variational equations along a non-equilibrium particular solution. The second, global ones, are obtained from the simultaneous analysis of variational equations related to all particular solutions belonging to a certain class. The marriage of these two types of the integrability obstructions enables to realize the classification programme of all integrable homogeneous systems. The main steps of the integrability analysis for systems with two and more degrees of freedom as well as new integrable systems are shown.
CIRCULAR INSTANTANEOUS FREQUENCY
Authors: PAI P. FRANK
Published: January 2010

This work defines the unique instantaneous frequency (IF) of an arbitrary time signal to be the circular instantaneous frequency (cIF) of the curvature radius of the signal's trajectory on the phase plane, where the signal's conjugate part is obtained from Hilbert transform (HT). Because a general signal of a dynamical system of multiple degrees of freedom contains multiple modal vibrations, its cIF varies dramatically and is not useful for system identification and other applications. If the signal is decomposed into modal vibration components without moving average, each component has no local extrema within each fundamental period and no local loops on the phase plane, each component's referred instantaneous frequency (rIF) with respect to the origin on the phase plane may be non-circular but is always non-negative, and the time-varying rIF and referred instantaneous amplitude (rIA) are convenient for combining the use of perturbation analysis for system identification. The empirical mode decomposition (EMD) of Hilbert–Huang transform (HHT) is valuable for decomposing a general nonlinear nonstationary signal into zero-mean intrinsic mode functions (IMFs), and HT enables accurate calculation of rIF and rIA of each IMF. Although the concept of circular frequency cannot be used for signal decomposition, it enables the development of time-domain-only techniques for online frequency tracking. A 5-point frequency tracking method is developed to eliminate the incapability of the original 4-point Teager–Kaiser algorithm (TKA) for frequency tracking of signals with moving averages. Moreover, a 3-point conjugate-pair decomposition (CPD) method is derived based on circle-fitting using a pair of conjugate harmonic functions. It is shown that both CPD and TKA are based on the concept of circle fitting, but TKA uses finite difference and CPD uses curve fitting in numerical implementation. However, the accuracy of TKA is easily destroyed by noise because of the use of finite difference. On the other hand, because CPD is based on curve fitting, noise filtering is an implicit capability and its accuracy increases with the number of processed data points. The rIF from HHT and the cIF from CPD and TKA are different by definition. Moreover, because the instantaneous frequency and amplitude are assumed to be constant in CPD and TKA, the cIF from CPD and TKA also deviates from the exact cIF.
THE BRIDGES WITH UNSEATING PREVENTION DEVICES ANALYZED THROUGH NONLINEAR TIME HISTORY ANALYSIS AND HILBERT–HUANG TRANSFORM
Authors: LI YEOU-FONG , HSU TSENG-HSING , LEN K. H.
Published: January 2010

In this paper, the mechanical behaviors of bridges with unseating prevention devices in the superstructure were investigated. These devices can prevent bridge from unseating and divert most of the seismic forces from transferring to the bridge columns. The models of the rubber bearing, restrainer, and shear key were proposed and implemented into the SAP 2000 to obtain the seismic response of the bridge. The nonlinear time history analysis was used to determine the time history response of the superstructure of the bridge. In the meantime, the Hilbert–Huang Transform (HHT) was used to transfer the displacement–time responses of the superstructure of the bridge into the time–frequency domain, while the spectra are a function of both frequency and time. The spectra of the HHT can be used to determine the operation sequences of the unseating prevention devices.