bluuebunny/crossref_metadata_2025 huggingface dataset:
Unexpected warming‐induced growth decline in Thuja occidentalis at its northern limits in North America
Authors: Housset Johann M. , Girardin Martin P. , Baconnet Mathieu , Carcaillet Christopher , Bergeron Yves
Published: April 2015

Aim

Towards the cold margins of the Northern Hemisphere boreal zone, continuing warming should theoretically provide a longer vegetative season, favouring growth and a northward shift in tree species distribution. The northern distribution of Thuja occidentalis L. (eastern white cedar) is marked by the presence of isolated marginal populations distant from the continuous distribution. If those populations proved to be well adapted to their future local climatic conditions, their expansion could accelerate cedar poleward migration. We tested the hypotheses that (1) there will be a growth increase in cedar northern marginal populations as a result of global warming, and (2) the edaphic conditions and regional precipitation regimes will modulate their response to warming.

Location

Canadian boreal forest, western Québec (47–50° N, 74–80° W).

Methods

We investigated radial growth using tree‐ring measurements from dominant and co‐dominant eastern white cedar trees (n = 723) distributed along a latitudinal gradient from the species' northern margin to the centre of its natural range. First, low‐frequency growth variations were analysed on whole chronologies (ad 1720–2010). Second, inter‐annual growth variations were tested against ad 1953–2010 monthly temperature and precipitation time series with a bootstrapped correlation function. Finally, the impact of environmental variables on the growth–climate relationships was assessed.

Results

Unexpectedly, a growth decline was observed starting in 1980 in marginal sites. Dendroclimatic analyses revealed that radial growth was not only limited by short growing seasons but also by summer droughts in the marginal zone. This response was exacerbated in sites that received less summer precipitation. Counterintuitively, autumn and spring precipitation negatively impacted on growth, especially in wet soil stands.

Main conclusions

Northern marginal populations of cedar may have already reached their optimum temperature threshold for radial growth. Our results suggest that they will probably be facing increasing hydric stress selection pressure under the assumptions of climate change. Their responses to future warming will be highly dependent on the seasonality and magnitude of variation in precipitation regimes.
Cardiac and hepatic role of r‐AtHSP70: basal effects and protection against ischemic and sepsis conditions
Authors: Pasqua Teresa , Filice Elisabetta , Mazza Rosa , Quintieri Anna Maria , Carmela Cerra Maria , Iannacone Rina , Melfi Donato , Indiveri Cesare , Gattuso Alfonsina , Angelone Tommaso
Published: April 2015

Heat shock proteins (HSPs), highly conserved in all organisms, act as molecular chaperones activated by several stresses. The HSP70 class of stress‐induced proteins is the most studied subtype in cardiovascular and inflammatory disease. Because of the high similarity between plant and mammalian HSP70, the aim of this work was to evaluate whether recombinant HSP70 of plant origin (r‐AtHSP70) was able to protect rat cardiac and hepatic function under ischemic and sepsis conditions. We demonstrated for the first time that, in ex vivo isolated and perfused rat heart, exogenous r‐AtHSP70 exerted direct negative inotropic and lusitropic effects via Akt/endothelial nitric oxide synthase pathway, induced post‐conditioning cardioprotection via Reperfusion Injury Salvage Kinase and Survivor Activating Factor Enhancement pathways, and did not cause hepatic damage. In vivo administration of r‐AtHSP70 protected both heart and liver against lipopolysaccharide‐dependent sepsis, as revealed by the reduced plasma levels of interleukin‐1β, tumour necrosis factor alpha, aspartate aminotransferase and alanine aminotransferase. These results suggest exogenous r‐AtHSP70 as a molecular modulator able to protect myocardial function and to prevent cardiac and liver dysfunctions during inflammatory conditions.
Mating scars reveal mate size in immature female blue shark Prionace glauca
Authors: Calich H. J. , Campana S. E.
Published: April 2015

The objective of this study was to determine the size and maturity status of the male blue sharks Prionace glauca attempting to mate with small, immature females in the north‐west Atlantic Ocean. The relationship between male curved fork length (LFC) and jaw gape was used in conjunction with the diameter of the mating scar to estimate the LFC and infer the maturity status of the male shark that produced the mating scar. The results indicate that mature males with a mean ± s.d. LFC of 218 cm ± 23 cm were attempting to mate with sexually immature females.
Risks and advantages of using surface laser photogrammetry on free‐ranging marine organisms: a case study on white sharks Carcharodon carcharias
Authors: Leurs G. , O'Connell C. P. , Andreotti S. , Rutzen M. , Vonk Noordegraaf H.
Published: April 2015

This study employed a non‐lethal measurement tool, which combined an existing photo‐identification technique with a surface, parallel laser photogrammetry technique, to accurately estimate the size of free‐ranging white sharks Carcharodon carcharias. Findings confirmed the hypothesis that surface laser photogrammetry is more accurate than crew‐based estimations that utilized a shark cage of known size as a reference tool. Furthermore, field implementation also revealed that the photographer's angle of reference and the shark's body curvature could greatly influence technique accuracy, exposing two limitations. The findings showed minor inconsistencies with previous studies that examined pre‐caudal to total length ratios of dead specimens. This study suggests that surface laser photogrammetry can successfully increase length estimation accuracy and illustrates the potential utility of this technique for growth and stock assessments on free‐ranging marine organisms, which will lead to an improvement of the adaptive management of the species.
Using an Industrial Waste Account to Facilitate National Level Industrial Symbioses by Uncovering the Waste Exchange Potential
Authors: Chen Pi‐Cheng , Ma Hwong‐wen
Published: April 2015

The identification of potential by‐product exchanges is important for fostering industrial symbiosis. To discover these potential exchanges, this article extends the analysis of local industrial symbiosis to a national scale. A waste input‐output table, which is a material flow accounting tool, was compiled and used as a database to examine the existing exchanges of by‐products. The supplies and demands of industrial wastes or by‐products were compared to highlight their potential use for promoting higher exchange flows. The analysis of the linkages indicated that the majority of each of the by‐products were reused by the few industries that had the technology and operational capacity for reuse. This finding is useful for determining which industries are good candidates for promoting further industrial symbiosis (IS). Based on a nation‐wide analysis that considered the industrial characteristics of Taiwan comprehensively, 23 types of major by‐products with greater reuse flows and 216 potential exchange patterns were identified between the industries. In addition, three types of eco‐industrial networks were characterized as follows according to their dominant types: (1) fossil fuel, metal, and mineral‐dominated; (2) agricultural and synthetic material‐dominated; and (3) information and communications technology (ICT) and chemical industry‐dominated eco‐industrial networks. This analysis highlights the resource exchange potentials and provides information to new firms for networking with existing businesses.
Hyperthermia‐induced seizures alter adenosine A1 and A2A receptors and 5′‐nucleotidase activity in rat cerebral cortex
Authors: León‐Navarro David Agustín , Albasanz José L. , Martín Mairena
Published: April 2015

Febrile seizure is one of the most common convulsive disorders in children. The neuromodulator adenosine exerts anticonvulsant actions through binding adenosine receptors. Here, the impact of hyperthermia‐induced seizures on adenosine A1 and A2A receptors and 5′‐nucleotidase activity has been studied at different periods in the cerebral cortical area by using radioligand binding, real‐time PCR, and 5′‐nucleotidase activity assays. Hyperthermic seizures were induced in 13‐day‐old rats using a warmed air stream from a hair dryer. Neonates exhibited rearing and falling over associated with hindlimb clonus seizures (stage 5 on Racine scale criteria) after hyperthermic induction. A significant increase in A1 receptor density was observed using [3H]DPCPX as radioligand, and mRNA coding A1 was observed 48 h after hyperthermia‐induced seizures. In contrast, a significant decrease in A2A receptor density was detected, using [3H]ZM241385 as radioligand, 48 h after hyperthermia‐evoked convulsions. These short‐term changes in A1 and A2A receptors were also accompanied by a loss of 5′‐nucleotidase activity. No significant variations either in A1 or A2A receptor density or 5′‐nucleotidase were observed 5 and 20 days after hyperthermic seizures. Taken together, both regulation of A1 and A2A receptors and loss of 5′‐nucleotidase in the cerebral cortex suggest the existence of a neuroprotective mechanism against seizures.

image

Febrile seizure is one of the most common convulsive disorders in children. The consequences of hyperthermia‐induced seizures (animal model of febrile seizures) on adenosine A1 and A2A receptors and 5'‐nucleotidase activity have been studied at different periods in cerebral cortical area. A significant increase in A1 receptor density and mRNA coding A1 was observed 48 h after hyperthermia‐induced seizures. In contrast, a significant decrease in A2A receptor density and 5'‐nucleotidase activity was detected 48 h after convulsions evoked by hyperthermia. These changes suggest the possible existence of a neuroprotective mechanism against seizures.
Co-application of lidocaine and QX-572 induces divergent pain behaviours in mice
Authors: Shao Cui-Jie , Gao Yong , Zhao Li , Jin Dan , Wang Dan , Wang De-Qiang
Published: April 2015

Objectives

We investigated the analgesic effects of lidocaine (LDC) and lidocane derivative, QX-572, co-application on the evoked pain behaviour (complete Freund's Adjuvant (CFA)-induced) and spontaneous pain behaviour (formalin-induced) in mice.

Methods

The experiments were performed using adult male Kunming mice. Formalin-induced acute pain model and CFA-induced chronic pain model was established by injecting formalin and CFA, respectively. Separate injections of LDC and QX-572, or co-injection of LDC and QX-572, were performed to observe the differences in neurobehavioural responses, paw withdrawal latency (PWL) and mechanical withdrawal threshold (MWT).

Key findings

QX-572 injection alone did not influence PWL and MWT, but injection of LDC alone led to a substantial, but short-lived, elevation in PWL and MWT (45 min). Co-injection of LDC and QX-572, however, resulted in a significant increase in PWL and MWT (120 min) compared with the LDC group. Injection of LDC and QX-572 combination in the adjacent sciatic nerve also produced a long-lasting sensory-specific nerve block. Additionally, intraplantar co-injection of LDC and QX-572 combination inhibited spontaneous pain in formalin-treated mice, but did not detectably attenuated hyperalgesia and allodynia in CFA-treated mice.

Conclusions

Our results provide evidence that QX-572 induced sensory-selective blockade and co-injection of QX-572 and LDC enhance pain blockade, as evident from formalin-treated mice.
Understanding the mechanisms of antitropical divergence in the seabirdWhite‐facedStorm‐petrel (Procellariiformes:Pelagodroma marina) using a multilocus approach
Authors: Silva Mónica C. , Matias Rafael , Wanless Ross M. , Ryan Peter G. , Stephenson Brent M. , Bolton Mark , Ferrand Nuno , Coelho M. Manuela
Published: April 2015

Analytical methods that apply coalescent theory to multilocus data have improved inferences of demographic parameters that are critical to understanding population divergence and speciation. In particular, at the early stages of speciation, it is important to implement models that accommodate conflicting gene trees, and benefit from the presence of shared polymorphisms. Here, we employ eleven nuclear loci and the mitochondrial control region to investigate the phylogeography and historical demography of the pelagic seabirdWhite‐facedStorm‐petrel (Pelagodroma marina) by sampling subspecies across its antitropical distribution. Groups are all highly differentiated: global mitochondrial ΦST = 0.89 (P < 0.01) and global nuclear ΦSTvaries between 0.22 and 0.83 (allP < 0.01). The complete lineage sorting of the mitochondrial locus between hemispheres is corroborated by approximately half of the nuclear genealogies, suggesting a long‐term antitropical divergence in isolation. Coalescent‐based estimates of demographic parameters suggest that hemispheric divergence ofP. marinaoccurred approximately 840 000 ya (95%HPD582 000–1 170 000), in the absence of gene flow, and divergence within the Southern Hemisphere occurred 190 000 ya (95%HPD96 000–600 000), both probably associated with the profound palaeo‐oceanographic changes of thePleistocene. A fledgling sampled inStHelena (tropicalSouthAtlantic) suggests recent colonization from theNorthernHemisphere. Despite the great potential for long‐distance dispersal,P. marinaantitropical groups have been evolving as independent, allopatric lineages, and divergence is probably maintained by philopatry coupled with asynchronous reproductive phenology and local adaptation.
Hyperleptinaemia, insulin resistance and survival in peritoneal dialysis patients
Authors: Cao Liou , Mou Shan , Fang Wei , Gu Leyi , Huang Jiaying , Gu Aiping , Qian Jiaqi , Ni Zhaohui
Published: April 2015

Aim

The aim of this study was to clarify the relationship between insulin resistance (IR) and glucose and lipid metabolism in peritoneal dialysis (PD) patients. The study also investigated the prognostic factors for survival in long‐term peritoneal dialysis patients.

Methods

Participants were recruited from July 1 to August 1, 2011, based on selection criteria. Patients were divided into two groups, high (H) and low (L) group according to the median value of homeostasis model assessment of IR (HOMA‐IR). Type 2 diabetes mellitus (DM) patients were chosen as positive controls. Clinical, plasma biochemical and metabolic parameters were observed and recorded at the outset and follow‐up of this study. Mortality related factors were also detected, and statistical analyses were performed.

Results

A total of 157 cases with an average age of 55 ± 15 years were included. There were 26, 66 and 65 cases in the DM, H and L groups, respectively. Younger age, lower body mass index, high sensitive C‐reactive protein (hsCRP) level, higher normalized protein catabolic rate (nPCR) were found in the L group compared with the other two groups. HOMA‐IR positively correlated with age, leptin and triglyceride levels, and it negatively correlated with BMI. L group had better survival rate than H and DM groups. Dialysis duration, serum leptin level, nPCR and hsCRP were statistically associated with mortality.

Conclusion

Insulin resistance may play an important role in the pathophysiology of glucose and lipid metabolism. Dialysis duration, leptin, nPCR and hsCRP may be risk factors for mortality in PD patients.
Abnormal neuronal response to rectal and anal stimuli in patients with idiopathic fecal incontinence
Authors: Haas S. , Brock C. , Krogh K. , Gram M. , Lundby L. , Drewes A. M. , Laurberg S.
Published: April 2015

Background

The pathophysiology behind idiopathic fecal incontinence (IFI) is poorly understood. We hypothesized abnormal sensory pathways along the brain‐gut axis as a key player in this disease, reflected in cortical evoked potentials (CEP) from mechanical stimuli of the rectum and the anal canal.

Methods

CEPs were recorded during repeated rapid balloon distensions of the rectum and anal canal in 19 women with IFI (mean age: 60 ± 14, mean Wexner score: 14.7 ± 2.9) and in 19 healthy women (mean age: 56 ± 11, mean Wexner score: 1.1 ± 1.3). Latencies, amplitudes and topography of CEPs elicited by rectal distension were compared between the groups. CEPs from both rectal and anal distensions were examined using spectral band analysis of single sweeps determining the relative amplitude of five spectral bands as a proxy of neuronal processing.

Key Results

Compared to controls IFI patients had prolonged latency of CEPs from rectal distension by up to 27% (p < 0.001) while amplitudes and topography were similar (all p > 0.7 and all p > 0.23). Spectral analysis of CEPs from rectal distensions showed no difference (all p > 0.1) between groups. However, analysis of CEPs following distension of the anal canal resulted in abnormally low activity in beta (8–12 Hz; p < 0.001) band and high activity in the gamma (32–70 Hz; p = 0.04) band in patients.

Conclusions & Inferences

IFI seems to be associated with impaired ano‐rectal sensory functions in both the afferent fibers to the brain and the cortical processing of anal sensory pathways. This may play a central role for the pathogenesis of IFI.
MODELING AND FORECASTING MONTHLY AVERAGE WATER LEVELS BASED ON THE ELLIPTIC ORBIT MODEL
Authors: YANG ZONG‐CHANG
Published: April 2015

Evaluation and forecasting of water‐level fluctuation for one river is of increasing importance since it is intimately associated with human welfare and socioeconomic sustainability development. In this study, it is found that time series of monthly water‐level fluctuation exhibits annual cyclical variation. Then with annual periodic extension for monthly water‐level fluctuation, the so‐called “elliptic orbit model” is proposed for describing monthly water‐level fluctuation by mapping its time series into the polar coordinates. Experiments and result analysis indicate potentiality of the proposed method that it yields satisfying results in evaluating and forecasting monthly water‐level fluctuation at the monitoring stations in the Yangtze River of China. It is shown that the monthly water‐level fluctuation is well described by the proposed elliptic orbit model, which offers a vivid approach for modeling and forecasting monthly water‐level fluctuation in a concise and intuitive way.
Increased unilateral tendon stiffness and its effect on gait 2–6 years after Achilles tendon rupture
Authors: Agres A. N. , Duda G. N. , Gehlen T. J. , Arampatzis A. , Taylor W. R. , Manegold S.
Published: April 2015

Achilles tendon rupture (ATR) alters tissue composition, which may affect long‐term tendon mechanics and ankle function during movement. However, a relationship between Achilles tendon (AT) properties and ankle joint function during gait remains unclear. The primary hypotheses were that (a) post‐ATR tendon stiffness and length differ from the noninjured contralateral side and that (b) intra‐patient asymmetries in AT properties correlate to ankle function asymmetries during gait, determined by ankle angles and moments. Ultrasonography and dynamometry were used to assess AT tendon stiffness, strain, elongation, and rest length in both limbs of 20 ATR patients 2–6 years after repair. Three‐dimensional ankle angles and moments were determined using gait analysis. Injured tendons exhibited increased stiffness, rest length, and altered kinematics, with higher dorsiflexion and eversion, and lower plantarflexion and inversion. Intra‐patient tendon stiffness and tendon length ratios were negatively correlated to intra‐patient ratios of the maximum plantarflexion moment and maximum dorsiflexion angle, respectively. These results suggest that after surgical ATR repair, higher AT stiffness, but not a longer AT, may contribute to deficits in plantarflexion moment generation. These data further support the claim that post‐ATR tendon regeneration results in the production of a tissue that is functionally different than noninjured tendon.
The Maze and the Mirror: Voting Correctly in Direct Democracy
Authors: Nai Alessandro
Published: April 2015

Objectives

This article assesses the conditions under which voters are more likely to vote “correctly” in direct democratic ballots. We look for determinants of correct voting simultaneously at the individual and contextual levels through a multilevel approach. At the individual level we provide special attention to the level of sophistication and the use of cognitive heuristics. At the contextual level we will investigate how the nature and content of political campaigns—more specifically, their intensity and negativity—enhance correct voting. We test our empirical models in the “hard‐case” scenario of Swiss direct democracy. We propose an alternative approach for the measure of correct voting, one that makes a full use of survey data but that tries to replicate the original idea of comparison between uninformed and informed voters to establish the “correctness” of a decision.

Methods

We use two different data sets that cover all direct democratic votes held in Switzerland, at the federal level, between 1999 and 2005; this period covers 23 ballots, during which 75 different projects were voted. To measure correct voting and all individual variables we rely on the VOX survey data, collected on a representative sample of about 1,000 individuals after each direct democratic vote in Switzerland. To measure campaign intensity and negativity we rely on an original data set that codes the content of every campaign ad published in the six major Swiss newspapers during the month prior to each ballot.

Results

We show that political sophistication and the use of referential heuristics strongly enhance correct voting. Furthermore, at the contextual level, we show that campaigns with high intensity decrease correct voting, especially when combined with high negativity, even though the direct effect of negativity on correct voting is positive.

Conclusion

We contribute to the existing literature in a threefold way. First, our results provide an additional confirmation that correct voting exists under both individual and contextual influences. Second, we assess the presence and determinants of correct voting in direct democracy, a “hard‐case” scenario, and find that the share of citizens who vote correctly is in line with the levels found for American citizens during elections, and that the main determinants seem to hold for both elections and direct democracy. Third, our alternative approach to measure correct voting highlights that the original idea of comparison between uninformed and informed voters, usually dealt with through experimental protocols, can be replicated with survey data.
A multi‐system geochronology in the Ad‐3 borehole, Pannonian Basin (Hungary) with implications for dating volcanic rocks by low‐temperature thermochronology and for interpretation of (U–Th)/He data
Authors: Danišík Martin , Fodor László , Dunkl István , Gerdes Axel , Csizmeg János , Hámor‐Vidó Mária , Evans Noreen J.
Published: April 2015

Independent geochronological and thermal modelling approaches are applied to a biostratigraphically exceptionally well‐controlled borehole, Alcsútdoboz‐3 (Ad‐3), in order to constrain the age of Cenozoic geodynamic events in the western Pannonian Basin and to test the efficacy of the methods for dating volcanic rocks. Apatite fission track and zircon U–Pb data show two volcanic phases of Middle Eocene (43.4–39.0 Ma) and Early Oligocene (32.72 ± 0.15 Ma) age respectively. Apatite (U–Th)/He ages (23.8–14.8 Ma) and independent thermal and subsidence history models reveal a brief period of heating to 55–70 °C at ~17 Ma caused by an increased heat‐flow related to crustal thinning and mantle upwelling. Our results demonstrate that, contrary to common perception, the apatite (U–Th)/He method is likely to record ‘apparent’ or ‘mixed’ ages resulting from subsequent thermal events rather than ‘cooling’ or ‘eruption’ ages directly related to distinct geological events. It follows that a direct conversion of ‘apparent’ or ‘mixed’ (U‐Th)/He ages into cooling, exhumation or erosion rates is incorrect.
Implementation of a clinical decision support system improves compliance with restrictive transfusion policies in hematology patients
Authors: Butler Caroline E. , Noel Simon , Hibbs Stephen P. , Miles David , Staves Julie , Mohaghegh Payam , Altmann Paul , Curnow Elinor , Murphy Michael F.
Published: April 2015

BACKGROUND

There is increasing evidence for restrictive red blood cell (RBC) transfusion but compliance with recommended transfusion triggers is variable. A clinical decision support system (CDSS) has been found to reduce unnecessary transfusion in some clinical settings when physicians are advised they are noncompliant with the current guidelines. The objective was to assess the impact of a CDSS for blood product ordering in patients with hematologic disease.

STUDY DESIGN AND METHODS

All platelet (PLT) and RBC transfusions were identified in hematology patients in three periods: before (baseline), immediately after (CDSS1), and 7 months after implementation of CDSS for blood ordering (CDSS2). Compliance with the recommended transfusion triggers was monitored for all orders made by CDSS or non‐CDSS methods during each period.

RESULTS

Ninety‐seven patients with a variety of hematologic diagnoses received 502 RBC and 572 PLT transfusions during the three periods with no significant difference in 1) the mean number of transfusions per patient, 2) the proportion of patients transfused, 3) posttransfusion hemoglobin (Hb), and 4) pre‐ and posttransfusion PLT count, although mean pretransfusion Hb decreased. The proportion of noncompliant RBC and PLT transfusion requests improved from baseline to CDSS2 (69.0% to 43.4% p ≤ 0.005 for RBCs; and 41.9% to 31.2%, p = 0.16 for PLT) when all orders were compared, although this improvement was not significant at the 5% level for PLTs.

CONCLUSIONS

The introduction of CDSS for blood product ordering supported by education and physician feedback in the hematology setting had an immediate impact on improving compliance with guidelines for restrictive transfusion practice.
20 Years Experience Burning Heavy Fuels in Heavy Duty Gas Turbines
Authors: White A. O.
Published: April 2015

This paper covers the early experience of the author’s company in burning residual oils in their gas turbines and the problems that occurred. The laboratory invesgations and field tests that resulted in a fuel processing system that permitted satisfactory operation on a wide range of liquid fuels are described. The operating experiences, where residual fuels were successfully burned in a large number of units, are described. The most recent operating experience with residual and crude oils and heavy distillates is also covered. A list of the various installations with dates and hours of operation is included and it is concluded that heavy duty gas turbines burning heavy fuels will be established as the up-to-date source of economical power in many applications.
Newkirk Effect: Thermally Induced Dynamic Instability of High-Speed Rotors
Authors: Dimarogonas A. D.
Published: April 2015

The Newkirk Effect is the vibration change due to thermal distortion of a rotor caused by rubbing on stationary components. B. Newkirk first noticed this phenomenon in 1924 and gave a qualitative explanation for it. The effect is not yet well enough understood. This and the importance of it in designing high-speed turbine rotors demand further work in this area. In this work an analytic study was undertaken. The static bow due to an arbitrary heat input can be found from a convolution integral of a source bow function and a heat function. Utilizing the dynamic response of the system, the resulting dynamic bow was computed. This dynamic bow controls the generated heat and the associated heat function. The resulting model can be described by a complex integral equation which can be transformed into two nonlinear differential equations. The stability and the modes of these equations have been studied. The equations themselves were solved with numerical methods. Three modes of the Newkirk Effect were discovered: spiralling, oscillating, and constant modes. It was found that critical speeds only indirectly influence the modes. The important factor is still the dynamic characteristics of the system in the form of a phase angle. It is believed that this analysis can be used for the design of rotors free of rubbing at wide ranges of speeds.
Acoustic Behavior of Exhaust Heat Recovery Systems for Gas Turbines
Authors: Weiss Marv
Published: April 2015

Gas turbine exhaust heat recovery systems have demonstrated the ability to attenuate acoustic energy without the benefit of sound absorbing materials. This paper describes the mechanisms utilized by heat recovery steam generators (HRSG) and by regenerators to reduce exhaust noise. Included is a semi-empirical method by which the attenuation of an HRSG can be predicted. Attenuations exhibited by the heat recovery equipment are in excess of 10 dB.
A Procedure for Conducting and Evaluating Noise Surveys at Gas Turbine Installations
Authors: Waxham T. J.
Published: April 2015

Once a gas turbine station is put into operation, a noise survey is recommended to determine the sound levels created by the station as a whole and to pinpoint the individual levels of each major piece of equipment. The results of the survey can be used to evaluate the silencing equipment and to point out those places where additional sound treatment would be most beneficial. This paper presents a discussion of the three phases of a typical survey: Planning, Conducting, and Evaluating.
Gas Turbine Intake Systems in Unusual Environments
Authors: Hill D. G. T.
Published: April 2015

Properly conditioned intake air is vital for top operating performance of a turbine. Equipment selection is dependent upon many factors — dust concentration in the area — climatic conditions — space limitations. Seven basic environmental locations are discussed with regard to the dust concentration, particle sizes, temperature and weather conditions which frequently make them unusual environments. In far too many instances the basic decision to use some form of air intake filter is taken without a proper understanding of the prevailing environmental conditions at the proposed gas turbine location and equally important without a proper understanding of what a given generic type of filter can do for the turbine in terms of preventing corosion erosion, and fouling.
Installation and Operation of Two 240-Megawatt Peaking Plants Using the Largest Heavy-Duty Gas Turbines in the U.S.A.
Authors: Bruce Don
Published: April 2015

This paper describes two large gas turbine powered peaking stations, their installation and operation, and solutions to significant problems encountered. The design concept of modular power plant construction and how it can facilitate onsite setup time in a compact, remote controlled installation that is independent of external water supplies is also demonstrated. Electric power demand in a densely populated urban civilization is characterized by peaks and valleys during a 24-hr daily cycle. Of particular concern are the peaks of demand.
A Pressure Transducer for an Electronic Fuel Control
Authors: Maybach J. M.
Published: April 2015

A capacitive pressure transducer is described which was designed to measure compressor discharge pressure as an input to an electronic fuel control system for gas turbine engines in the power range of 400 to 1000 hp. Critical design requirements were size, cost, accuracy and stability. The transducer developed embodies new technology in the areas of sensing capsule design, overall package size, and transducer signal conditioning.
Lift and Measurements in an Aerofoil in Unsteady Flow
Authors: Holmes D. W.
Published: April 2015

A wind tunnel is described which is capable of producing both “transverse” and “streamwise” gusts. An account is given of the lift and pressure fluctuations measured on an isolated aerofoil tested in the tunnel. The response to a transverse gust compares well with Kemp’s (1) theory although the pressure distribution is not as predicted. The results suggest that the wake behavior and in particular the existence of a separation region can in practice seriously affect the validity of applying the now classical unsteady vortex theory.
An Electronic Dual Fuel System for Industrial and Marine Gas Turbines
Authors: Moss R. H. , Barnes B. B. , Harrison E.
Published: April 2015

The application of electronic fuel control systems to Industrial and Marine gas turbines is not a new concept. The last decade has seen considerable progress culminating with the appearance of a number of viable systems. This paper describes one such system which is now in quantity production. Its versatility, and novel features are described. Probably the most significant feature of the system is the electronic fuel transfer capability for dual fuel applications. This facility is given special mention because of its unique design. Photographs, and diagrams are included to illustrate relevant points. The author’s views on future systems are also discussed.
Remanufacture of Jet Engine Compressor Components
Authors: Weinstein Martin
Published: April 2015

A description of the various mechanical operations employed in the remanufacture of gas turbine engine compressor components such as blading, rotor disks and spacer, vane shroud assemblies and air seals are given. The operations described include tungsten inert gas, plasma needle arc and electron beam welding, furnace and torch brazing, glass bead and shot peening, magnetic particle and ultrasonic inspection, plasma spray and diffusion coating. Emphasis is given to the effect of these operations on the mechanical integrity of the engine component. For example, the effect of welding, brazing, peening and diffusion coating on the high cycle fatigue strength of compressor stator and rotor components is discussed. The effect of repair operations on jet engine compressor performance is also considered.
Silicon Nitride Materials for Gas Turbine Components
Authors: Caws R. B. , Graham R. P. , Stoddart D. E.
Published: April 2015

This paper deals with the use of silicon nitride for gas turbine components. Brief descriptions are given of the various process routes used and which components in a gas turbine could be made by such processes. Serious consideration is given to the question of design using a brittle material. The lack of a standardized test procedure for mechanical properties results in difficulty in presenting data in an absolute manner. Properties of interest are discussed and presented in such a way as to enable a designer to have a better initial understanding of the material and its potential in gas turbines.
Transonic Flow Through a Turbine Stator Treated as an Axisymmetric Problem
Authors: Schröder H. J. , Schuster P.
Published: April 2015

Some particularities of transonic flow through a turbine stator near choking limit become apparent by calculating the axisymmetric flow field. At the exit of a stator whose hug-to-tip ratio is reasonably low the flow is clearly subsonic at the outer casing, highly supersonic at the hub. The stream-tubes near the hub exhibit each a Laval throat further upstream. In the transonic zone remarkable values of the radial velocity are brought to light by a relaxation method. After-expansion may begin at subsonic or supersonic velocities. It is characterized by an expansion to overspeed and a formation of wakes the convection of which into the active stream is a cause of losses.
Hot Isostatic Pressing of Titanium Alloys for Turbine Engine Components
Authors: Harth G. H.
Published: April 2015

This paper presents the state-of-the-art knowledge concerning the application of powder metallurgy to the fabrication of titanium alloy turbine engine components. The effect of powder type, powder processing, and method of powder consolidation on the mechanical properties and microstructures of P/M parts it discussed. The advantages of using hot isostatic pressing (HIP) in producing engine components is outlined.
Hybrid Simulation of a Single-Shaft Gas Turbine Water Pump Drive
Authors: Schatborn I. W.
Published: April 2015

This paper describes the hybrid simulation of a single-shaft W 191 M gas turbine water pump drive, carried out to carefully adapt the control system to starting and stopping under load within plant operating limitations. For this simulation work, the hybrid computer favorably combines analog computer flexibility in the solving control problems with digital computer memory for storage of steady-state characteristics. The latter are generated using a new hybrid function generation technique for two independent variables.
Performance of Jet V/STOL Tactical Aircraft Nozzles
Authors: Miller E. H.
Published: April 2015

V/STOL aircraft impose stringent requirements on exhaust nozzles. In many cases, this type nozzle must provide a high level of thrust for liftoff and maintain it while vectoring. Grumman ran a test program to optimize V/STOL nozzle designs and obtain a basic understanding of the complicated exhaust nozzle flow process. The program made use of fiberglass models which were 1/6.5 scale of representative fighter designs. Tests were run statically with cold air. The configurations examined were cut-off plug, single bearing swivel-tee plenum, single bearing swivel-scroll plenum, and flap nozzle. The effects of number of vanes, Mach number, and distortion were examined. The performance of the nozzles was broken down into plenum and nozzle, where applicable.
The Sea Trials of the DDH 280 Class Destroyers
Authors: Healey E. J.
Published: April 2015

The first of a class of all-gas-turbine-powered warships was delivered to the Canadian Armed Forces in July of 1972. These ships are unique in that they represent the first warships built with this type of propulsion in the western world. This paper reviews the major design features of the plant and discusses in detail the dockside and sea trials of the 4400-ton vessels. The problems and successes of the trials in HMCS Iroquois are presented as this vessel was the first of the class.
A Practical Approach to Gas Turbine Maintenance
Authors: Donahoe P. G.
Published: April 2015

This paper details the necessary research required to define the problems associated with operation and maintenance of gas turbines at high availability and efficiency rates. After these have been categorized, the program developed to eliminate these problems is set forth. This includes the type of operator training aids, the frequency and depth of “running inspections,” the data trending and recording, to enable a good turbine operating history to be accumulated. This history is applied then during major and/or minor inspections as regards parts life. Inspection procedures are outlined and the paper is summarized by pointing the program to the problem areas that detract from availability and efficiency.
High Impact Shock Test of a General Electric LM2500 Propulsion Gas Turbine Module
Authors: Bobo W. R.
Published: April 2015

This paper discusses the high impact shock testing of a General Electric Propulsion Gas Turbine Module to the requirements of Military Specification MIL-S-901C. This shock qualification is just one of a comprehensive program of tests to be, performed to fully qualify the LM2500 Gas Turbine and the DD-963 Propulsion System components specifically for the Spruance (DD-963) Class Destroyers. The description of the gas turbine and the preparation for, and the conduct of the shock test, and a review of the shock test results are presented.
Nondestructive Inspection Method for Jet Engine Turbine Blades
Authors: Kraska I. R. , Berndt W. L.
Published: April 2015

Nondestructive inspection of jet engine turbine blades during field and depot maintenance is accomplished normally with fluorescent penetrant and/or visual techniques. In spite of the widespread use of the penetrant process, it has many disadvantages as a maintenance inspection method. The reliability of penetrant inspection depends upon the preparation of the blades prior to actual penetrant processing and the inspector’s skill in detecting and evaluating defect indications. The process can miss cracks if they are filled with material that blocks the penetrant from entering the defect. An eddy current technique which can detect leading and trailing edge cracks in turbine blades and an instrument based upon this technique were developed under Air Force sponsorship. The instrument has been tested in a rework facility and field maintenance. Results of the evaluation and photomicrographs of typical cracks detected in turbine blades are presented. Results are compared, in some instances, to results obtained with the fluorescent penetrant and/or visual examinations. A field penetrant inspection of leading trailing edges detect cracks at an inspection rate of one stage in 1 hr and 50 min.
The Unsteady Response of a Blade Row From Measurements of the Time-Mean Total Pressure
Authors: Henderson R. E.
Published: April 2015

An experimental procedure is described which permits the unsteady response of a rotating blade row to spatial variations in its inlet flow to be determined from measurements of the time-mean total pressure. This procedure has been employed to determine the unsteady circulation of a non-lifting rotor as a function of reduced frequency for two values of space-chord ratio. Comparisons of these experimental data are made with a recent theoretical analysis of the indirect or design problem of unsteady lift in a moving two-dimensional cascade. Both the experimental and theoretical data are shown to exhibit the same trends with variations in space-chord ratio and reduced frequency. These results demonstrate that the unsteady blade interference effects are significant, and that the representation of the unsteady response of a turbomachine blade row as an isolated airfoil is not valid for reduced frequencies less than 1.2.
Mechanical force releases nascent chain–mediated ribosome arrest in vitro and in vivo
Authors: Goldman Daniel H. , Kaiser Christian M. , Milin Anthony , Righini Maurizio , Tinoco Ignacio , Bustamante Carlos
Published: April 2015

Force to unblock a clogged ribosome

The synthesis of proteins from mRNA by the ribosome is highly regulated. But newly synthesized protein chains can still block the ribosome exit tunnel and slow protein synthesis. Goldman
et al.
use optical tweezers to show that by pulling on the stuck protein chain, they can unblock a clogged exit tunnel (see the Perspective by Puglisi). In vivo, the folding of a nascent protein chain just outside the tunnel also generates enough force to unclog a block, indicating that ribosome-peptide interactions fine-tune protein synthesis.

Science
, this issue p. 457; see also p. 399
House science chief unveils contentious vision for science
Authors: Mervis Jeffrey , Cho Adrian
Published: April 2015

Authorization bill would cut climate and energy research and reshape science agency policies.
NIH's peer review stands up to scrutiny
Authors: Mervis Jeffrey
Published: April 2015

Analyses show better scored proposals produce more papers and citations.
After Hubble
Authors: Clery Daniel
Published: April 2015

The Webb telescope's troubled history poses challenges for other contenders to replace the world's most popular space telescope.
Ecosystem services lost to oil and gas in North America
Authors: Allred Brady W. , Smith W. Kolby , Twidwell Dirac , Haggerty Julia H. , Running Steven W. , Naugle David E. , Fuhlendorf Samuel D.
Published: April 2015

Net primary production reduced in crop and rangelands
Evolving new organisms via symbiosis
Authors: Kiers E. Toby , West Stuart A.
Published: April 2015

When and how do symbiotic partnerships become new, integrated organisms?
Supramolecular lattices from tetrahedral nanobuilding blocks
Authors: Yang Shu
Published: April 2015

The location of hydrophilic and hydrophobic regions on tetrahedral nanoparticles determines how they pack together into a variety of structures

[Also see Report by

Huang
et al.

]
Biogeochemical tales told by isotope clumps
Authors: Passey Benjamin H.
Published: April 2015

Molecules with two or more heavy isotopes provide insights into diverse biological and geological phenomena

[Also see Reports by

Wang
et al.

and

Yeung
et al.

]
The delicate dance of translation and folding
Authors: Puglisi Joseph D.
Published: April 2015

RNA translation and protein folding affect each other during protein synthesis

[Also see Reports by

Kim
et al.

and

Goldman
et al.

]
Calcilytics for asthma relief
Authors: Penn Raymond B.
Published: April 2015

A promiscuous calcium receptor holds promise as a therapeutic target for asthma
Complete Genome Sequence of Kluyveromyces marxianus NBRC1777, a Nonconventional Thermotolerant Yeast
Authors: Inokuma Kentaro , Ishii Jun , Hara Kiyotaka Y. , Mochizuki Masao , Hasunuma Tomohisa , Kondo Akihiko
Published: April 2015

We determined the genome sequence of the thermotolerant yeast
Kluyveromyces marxianus
strain NBRC1777. The genome of strain NBRC1777 is composed of 4,912 open reading frames (ORFs) on 8 chromosomes, with a total size of 10,895,581 bp, including mitochondrial DNA.
Development of Conventional and Real-Time Quantitative PCR Assays for Diagnosis and Monitoring of Scabies
Authors: Wong Samson S. Y. , Poon Rosana W. S. , Chau Sandy , Wong Sally C. Y. , To Kelvin K. W. , Cheng Vincent C. C. , Fung Kitty S. C. , Yuen K. Y.
Published: April 2015

Scabies remains the most prevalent, endemic, and neglected ectoparasitic infestation globally and can cause institutional outbreaks. The sensitivity of routine microscopy for demonstration of
Sarcoptes scabiei
mites or eggs in skin scrapings is only about 50%. Except for three studies using conventional or two-tube nested PCR on a small number of cases, no systematic study has been performed to improve the laboratory diagnosis of this important infection. We developed a conventional and a real-time quantitative PCR (qPCR) assay based on the mitochondrial cytochrome
c
oxidase subunit 1 (
cox1
) gene of
S. scabiei
. The
cox1
gene is relatively well conserved, with its sequence having no high levels of similarity to the sequences of other human skin mites, pathogenic zoonotic mites, or common house dust mite species. This mitochondrial gene is also present in large quantities in arthropod cells, potentially improving the sensitivity of a PCR-based assay. In our study, both assays were specific and were more sensitive than microscopy in diagnosing scabies, with positive and negative predictive values of 100%. The
S. scabiei
DNA copy number in the microscopy-positive specimens was significantly higher than that in the microscopy-negative specimens (median
S. scabiei
DNA copy number, 3.604 versus 2.457 log
10
copies per reaction;
P
= 0.0213). In the patient with crusted scabies, the qPCR assay performed on lesional skin swabs instead of scrapings revealed that the parasite DNA load took about 2 weeks to become negative after treatment. The utility of using lesional skin swabs as an alternative sample for diagnosis of scabies by PCR should be further evaluated.