bluuebunny/crossref_metadata_2025_split huggingface dataset:
Season Does Not Influence Embryo Recovery Rate and Conceptus Size Until Day 14 After Ovulation in the Horse
Authors: Aurich C , Budik S 
Published: January 2015

ContentsAlthough the horse is a seasonal breeding species, a considerable number of mares continue to cycle throughout autumn and winter. Slower equine embryo growth during the non‐breeding season has been hypothesized, and because smaller embryo size is beneficial for cryopreservation, embryo collection outside the breeding season could be an interesting approach for the production of frozen horse embryos. In the present retrospective study, we have therefore analysed embryo recovery rates and conceptus size in mares (n = 30) throughout the year. Conceptus diameter was either size determined after collection with a microscopic scale (day 7–10 after ovulation) or determined by transrectal ultrasound immediately before collection (day 11–14 after ovulation). In 19 of the 30 mares (63%), ovulatory cycles were detected throughout the year. A total of 352 embryo collections with a mean recovery rate of 64.2% were performed and not affected by season. The size was analysed in a total of 165 conceptuses. Conceptus diameter significantly increased (p < 0.001) with day of pregnancy (e.g. day 7: 0.3 ± 0.04, day 10: 4.1 ± 0.2, day 12: 10.1 ± 0.5, day 14: 17.4 ± 0.9 mm), but was not influenced by season. In conclusion, successful embryo collection is possible throughout the year in spontaneously cyclic mares. Under these conditions, neither collection rates nor embryo growth appeared to be affected by season.
Farmers, Middlemen and Exporters: A Model of Market Power, Pricing and Welfare in a Vertical Supply Chain
Authors: Bjorvatn Kjetil , Milford Anna B. , Sørgard Lars 
Published: January 2015

AbstractMarkets for cash‐crops in developing countries are typically characterized by a concentration of buyer power at different levels of the supply chain. For instance, small‐scale coffee farmers sell their produce to a middleman, who in turn sells the coffee onward to an exporter, often a foreign multinational, with monopsony power in the hands of the purchasers at both levels. We analyze pricing behavior and welfare with different assumptions regarding market power. In particular, we show that a more powerful exporter is likely to benefit the producers and may even lead to higher welfare for the producer country as a whole.
Decomposition of Productivity Considering Multi‐environmental Pollutants in Chinese Industrial Sector
Authors: Fujii Hidemichi , Cao Jing , Managi Shunsuke 
Published: January 2015

AbstractThe objective of this study is to calculate and decompose productivity incorporating multi‐environmental pollutants in Chinese industrial sectors from 1992 to 2008. We apply a weighted Russell directional distance model to calculate productivity from both the economic and environmental performance. The main findings are: (1) Chinese industrial sectors increased productivity, with the main contributing factors being labor saving prior to 2000; (2) The main contributing factors for productivity growth in coastal areas include both economic and environmental performance improvement. While central and western regions improved productivity owing to economic development, they have a trade‐off relationship between economic and environmental performance.
Evidence for Financial Contagion in Endogenous Volatile Periods
Authors: Kilic Erdem , Ulusoy Veysel 
Published: January 2015

AbstractThe objective of this study is to analyze cross‐border contagious dynamics in both foreign exchange markets and stock exchange markets. Propagation is analyzed with respect to the transmission of excessive volatility that is endogenously determined. The contagion process is discussed in the context of financial systems, foreign direct investments and trade. Implementing a vector autoregressive‐multivariate generalized autoregressive conditional heteroskedasticity (VAR‐MGARCH) model, we show that country‐specific turbulence in financial markets is able to create unanticipated financial contagion across countries. Diversified trade and financial relations decrease the risk of exposure to contagion from external markets. The world's largest economies, however, play a price‐setter role, and diversification is of secondary importance. Asymmetric transmission of the empirically predicted contagion prevails in the latter case.
PRC Outward Investment in the USA and Europe: A Model of R&D Acquisition
Authors: Pelzman Joseph 
Published: January 2015

AbstractIn this paper, I present a theoretical framework designed to explain People's Republic of China (PRC) outward foeign direct investment in the USA and Europe, in search of research and development (R&D) acquisition modeled as positive “spillover effects” in a two‐country model with firms distinguished by their ability to innovate. The motivation for this paper is the growing PRC merger and acquisition activity in Europe and the USA. The fact that the PRC, despite its many successful internal reforms, cannot induce innovation activity designed to alter its external sector from one that is based on cheap labor to one that is based on innovation‐rich products, has forced it to use its extensive reserve holdings to acquire the necessary R&D via merger and acquisition. These acquisitions will allow the PRC to alter their domestic and export product mix and thus avoid the middle‐income trap.
FDI, Foreign Aid, Remittance and Economic Growth in Developing Countries
Authors: Nwaogu Uwaoma G. , Ryan Michael J. 
Published: January 2015

AbstractUsing a dynamic spatial framework, this paper investigates how foreign direct investment (FDI), foreign aid and remittances impact the economic growth of 53 African and 34 Latin American and Caribbean countries. Previous growth studies examine how one factor or two of these factors impacts economic growth, which results in biased estimation because of the omitted variable(s). Separate estimation shows foreign aid and FDI affects economic growth in Africa, but when we control for all three factors, only FDI affects African economic growth. For Latin America and the Caribbean, foreign aid and remittances affect growth when estimated separately, while remittances affect growth when they are estimated simultaneously. Finally, both regions' results confirm spatial interdependence is important in explaining economic growth, as growth in one country depends on the growth of its neighboring countries.
Adjusting for Selection Bias in Assessing the Relationship Between Sibship Size and Cognitive Performance
Authors: Ghilagaber Gebrenegus , Wänström Linda 
Published: January 2015

SummaryConsistent negative correlations between sibship size and cognitive performance (as measured by intelligence quotient and other mental aptitude tests) have been observed in past empirical studies. However, parental decisions on family size may correlate with variables affecting child cognitive performance. The aim of this study is to demonstrate how selection bias in studies of sibship size effects can be adjusted for. We extend existing knowledge in two aspects: as factors affecting decisions to increase family size may vary across the number and composition of current family size, we propose a sequential probit model (as opposed to binary or ordered models) for the propensity to increase family size; to disentangle selection and causality we propose multilevel multiprocess modelling where a continuous model for performance is estimated jointly with a sequential probit model for family size decisions. This allows us to estimate and adjust for the correlation between unmeasured heterogeneity affecting both family size decisions and child cognitive performance. The issues are illustrated through analyses of scores on Peabody individual achievement tests among children of the US National Longitudinal Survey of Youth 1979. We find substantial between-family heterogeneity in the propensity to increase family size. Ignoring such selection led to overestimation of the negative effects of sibship size on cognitive performance for families with 1–3 children, when known sources of selection were accounted for. However, the multiprocess modelling proposed could efficiently identify and control for such bias due to adverse selection.
Urine incontinence in women aged sixty to sixty‐five: negotiating meaning and responsibility
Authors: Róin Ása , Nord Catharina 
Published: January 2015

BackgroundUrine incontinence (UI) has been the focus of a considerable number of research projects; yet, there is no evidence that the research has had an impact on the prevalence of UI. Despite great impact on daily living, women seem to be reluctant to seek help from professionals or talk about the problem. Apart from this, scholars have noted that healthcare practitioners rarely ask older women about this health aspect and seem to minimise the problem when confronted with it.AimThe purpose of the study was to explore how meaning of UI was discursively constructed and negotiated by women bothered with long‐term UI in the context of research interviews.MethodSeven women aged 60–65 living in the Faroe Islands were interviewed to elaborate on daily living with long‐term UI. The interview texts were analysed by means of discourse analysis.ResultsThree main themes emerged from the interviews. All the women related the disorder to their age and positioned themselves within the category ‘old women’ for whom UI was considered a normal condition. At the same time, they opposed to the idea that the condition was inevitable and accused their general practitioners of negligence by failing to take their complaints seriously. They felt ashamed of being incontinent and seemed to subject themselves to moral and aesthetic views about people who were not able to control their bladder function.ConclusionAll the women used different cultural discourses to make meaning of UI and continuously negotiated these meanings. Avoiding public exposure of their leaking problem restricted their daily living, and the embarrassment of not being able to control their bladder function seemed to overrule any wish of actively dealing with their present condition.
Estimating Particle Shape and Orientation Using Volume Tensors
Authors: Ziegel Johanna F. , Nyengaard Jens R. , Vedel Jensen Eva B. 
Published: January 2015

AbstractWe develop statistical procedures for estimating shape and orientation of arbitrary three‐dimensional particles. We focus on the case where particles cannot be observed directly, but only via sections. Volume tensors are used for describing particle shape and orientation, and we derive stereological estimators of the tensors. These estimators are combined to provide consistent estimators of the moments of the so‐called particle cover density. The covariance structure associated with the particle cover density depends on the orientation and shape of the particles. For instance, if the distribution of the typical particle is invariant under rotations, then the covariance matrix is proportional to the identity matrix. We develop a non‐parametric test for such isotropy. A flexible Lévy‐based particle model is proposed, which may be analysed using a generalized method of moments in which the volume tensors enter. The developed methods are used to study the cell organization in the human brain cortex.
The Grammars of Conjunction Agreement in Slovenian
Authors: Marušič Franc , Nevins Andrew Ira , Badecker William 
Published: January 2015

AbstractIn this paper we report on the results of five experiments documenting the existence of three distinct grammars of conjunct agreement in Slovenian, found both within and across individuals: agreement with the highest conjunct, agreement with the closest conjunct, or agreement with the Boolean Phrase itself. We show that this variation is constrained and that some of these mechanisms can be blocked and/or forced depending on the properties of the conjuncts. Finally, we offer the suggestion that the presence of intraindividual variation arises because of ambiguous properties of the primary linguistic data.
Do Developing‐country WTO Members Receive More Aid for Trade (AfT)?
Authors: Lee Hyun‐Hoon , Park Donghyun , Shin Meehwa 
Published: January 2015

AbstractSince the World Trade Organization (WTO) Doha Development Agenda (DDA) negotiations started in 2001, the importance of aid for trade (AfT) has been well recognised as a useful tool for facilitating trade, economic growth and social development in developing countries. At the WTO Hong Kong Ministerial Conference in December 2005, the ‘AfT initiative’ was launched and many high‐income member countries pledged to increase their AfT contributions, particularly for the least developed member countries (LDC). This paper aims to assess whether and to what extent the WTO's developing member countries have received more AfT. For this purpose, a system generalised method of moments is applied to a sample of 118 recipient countries for the period 2001–10. We find evidence that while LDC WTO members on average receive relatively more AfT than other developing countries, the difference has not increased since launch of the AfT initiative. Among the three categories of AfT, the positive WTO membership effect for LDC members increased for building productive capacity and for trade policy and regulation, but declined for infrastructure.
The Coal-Fired PFBC Machine: Operating Experience and Further Development
Authors: Jansson Sven A. , Veenhuizen Dirk , Pillai Krishna K. , Björklund Jan 
Published: January 2015

The key components of Pressurized Fluidized Bed Combined Cycle (PFBC) plants are the specially designed gas turbine, which we refer to as the PFBC machine, and the pressurized fluidized bed boiler used to generate and superheat steam for expansion in a steam turbine, in ABB’s P200 and P800 modules, ABB Stal’s 17 MWe GT35P and 70 MWe GT140P machines, respectively, are used. Particulate cleanup before expansion in the turbine sections is with cyclones.
So far, over 70,000 hours of operation has been accumulated on P200 modules in the world’s first PFBC plants, demonstrating that PFBC meets the expectations. The GT35P machines have been found to perform as expected, although some teething problems have also been experienced. The next P200 plant will be built in Germany for operation on brown coal. The first GT140P machine has been manufactured. After shop testing in Finspong, it will be shipped to Japan for installation in the first P800 plant, which is under construction.
Future development of the PFBC machines are foreseen to include raising the turbine inlet temperature through combustion of a topping fuel in order to reach thermal efficiencies which ultimately may be in the range of 50 to 53% (LHV).
Heavy-Duty Gas Turbine Plant Aerothermodynamic Simulation Using Simulink
Authors: Crosa G. , Pittaluga F. , Trucco Martinengo A. , Beltrami F. , Torelli A. , Traverso F. 
Published: January 2015

This paper presents a physical simulator for predicting the off-design and dynamic behaviour of a single shaft heavy-duty gas turbine plant, suitable for gas-steam combined cycles.
The mathematical model, which is non linear and based on the lumped parameter approach, is described by a set of first-order differential and algebraic equations. The plant components are described adding to their steady state characteristics the dynamic equations of mass, momentum and energy balances. The state variables are mass flow rates, static pressures, static temperatures of the fluid, wall temperatures and shaft rotational speed.
The analysis has been applied to a 65 MW heavy-duty gas turbine plant with two off-board silo-type combustion chambers. To model the compressor, equipped with variable inlet guide vanes, a subdivision into five partial compressors is adopted, in serial arrangement, separated by dynamic blocks. The turbine is described using a one dimensional row by row mathematical model, that takes into account both the air bleed cooling effect and the mass storage among the stages. The simulation model considers also the air bleed transformations from the compressor down to the turbine.
Both combustion chambers have been modelled utilising a sequence of several sub-volumes, to simulate primary and secondary zones in presence of three hybrid burners.
A code has been created in Simulink environment. Some dynamic responses of the simulated plant, equipped with a proportional-integral speed regulator, are presented.
Combustion System Development for Dry Low-NOx Emission and High Turbine Inlet Temperatures
Authors: Becker Bernard , Schulten Wilhelm , Schetter Bernhard 
Published: January 2015

The last 10 years of combustor development are characterised by the introduction of lean premixed burners for dry low-NOx emissions. This was easy to achieve as long as sufficient excess air was available. The modern gas turbine with its high turbine inlet temperature and increased need for component cooling sees a competition for air between combustion and requirements in other areas.
The paper describes how these problems have been solved by changing the design of burners and combustion chambers. The goal of minimising the hot surface area for a given combustor volume is achieved with the annular combustors. The number of burners has been selected in order to achieve good cross ignition, uniform temperature distribution and reasonably short residence times with the minimum of components. Test results and experience with operation and maintenance are also reported.
Experimental and Numerical 3-D Investigations of the Flow Field Behind the Trailing Edge of a Cooled Turbine Guide Vane
Authors: Bohn Dieter E. , Becker Volker J. , Behnke Klaus D. 
Published: January 2015

Experimental investigations have been carried out to analyze the hot gas flow and cooling gas flow in the direct vicinity of the trailing edge of a modern gas turbine vane, with cooling gas ejection through the trailing edge. The investigations were performed in one of the institute’s test turbines. The experimental set-up is designed to establish variable blowing ratios between cooling gas mass flow and hot gas mass flow. An alternative density ratio between hot gas and cooling gas was established by the use of CO2 instead of air as the cooling gas for cold test runs. The experimental investigations have been carried out for different radial positions. The measurement plane was located 0.2mm to 0.5mm downstream of the trailing edge (trailing edge width 1.6mm).
Local regions of high anisotropic turbulence were detected in the mixing zone. For low blowing ratios, the trailing edge pressure side in the tip vicinity was found to be subjected to direct hot gas contact. The trailing edge ejection has an influence of at least one chordlength in axial direction.
The experimental investigations were accompanied by 3-D Navier-Stokes computational simulations. The calculated velocity distributions were found to be quite consistent with the experimental results. The calculated flow angles differed locally from the measurements. This may be due to the turbulence model employed.
Crack Detection, Localization and Estimation of the Intensity in a Turbo Rotor
Authors: Park R.-W. 
Published: January 2015

The goal of this paper is to describe an advanced method of a crack detection, a new way to localize the crack position and to estimate the intensity of the depth with reference to a rotating shaft. As a first step, the shaft is physically modelled with a finite element method as usual and the dynamic mathematical model is derived from it using the Hamilton-principle and in this way the system is modelled by various subsystems. The equations of motion with crack is established by adaption of the local stiffness change through breathing and gaping from the crack to the equation of motion with undamaged shaft. This is supposed to be regarded as reference for the given system.
Based on the fictitious model of the time behaviour induced from vibration phenomena measured at the bearings, a nonlinear State Observer is designed in order to detect the crack on the shaft. This is elementary NL-observer (EOB). Using the elementary observer, an Estimator (Observer) Bank is established and arranged at the certain position on the shaft. In case a crack is found and its position is known, the procedure for the estimation of the depth is going to begin.
Laser Drilling Effusion Cooling Holes in Low NOx Turbine Engine Components
Authors: VanderWert Terry L. , Litzer Scott A. , Meng Loh Wai 
Published: January 2015

The move to turbine engine designs featuring low NOx emissions and greater fuel efficiency has resulted in a major change in design and manufacture of certain engine parts such as combustion chambers. For example, effusion cooling combustor designs use thousands of 0.5 mm diameter, shallow angle (less than 30 degrees from the surface) holes to provide a film of cooling air over the surface of the combustor. A variety of thermal barrier coatings are also used to protect the surface during operation.
Laser drilling is playing a key role in the production of effusion cooling holes. Laser drilling, which uses the focused output of a high power industrial pulsed Nd:YAG laser to trepan the holes, has become the process of choice for producing these because of:
- low heat input
- rapid drilling rates
- ability to drill ceramic coated metals
- a minimum number of process variables contributes to reliable, repeatable processes
This paper reviews the laser drilling process for producing effusion cooling holes, characteristics of the holes, and developments aimed at increasing the throughput and, therefore, reducing the cost for laser drilling. The paper also summarizes the key aspects of the laser system required to produce combustors that meet airflow and other quality (metallurgical) specifications.
Part Load Conditions of Complex Cycle Power Plants With Intercooled Gas Turbine
Authors: Peretto A. 
Published: January 2015

The present paper evaluates the behavior, in design and part load working conditions, of a complex gas turbine cycle with multiple intercooled compression, and the optional preheating of the air at the high pressure compressor outlet by means of the gas turbine outlet hot gas.
The results are then compared with those obtained by a Brayton cycle gas turbine, with or without preheating of the air at the high pressure compressor outlet.
Subsequently, the performance of complex combined cycles, with intercooled gas turbine as topper and one, two or three pressure level steam cycle as bottomer, in design and part load working conditions is also evaluated.
The performance of these complex combined plants is then compared with that obtained by a Brayton cycle gas turbine as topper and one, two or three pressure level steam cycle as bottomer.
Part load working conditions are realized by varying either the inlet guide vane angle of the first compressor nozzles or the maximum temperature at the combustor outlet.
The study shows that in part load working conditions obtained by varying IGV, the complex cycles, in the examined gas turbine or in the combined cycle power plants, give conversion efficiencies decidedly greater than those obtainable by varying combustor exit temperature.
Furthermore it is found that these complex power plant efficiencies, in part load working conditions, are far greater than those obtained by the Brayton cycle gas turbine, or by combined cycle with Brayton cycle gas turbine as topper, if IGV adjustment is adopted.
If power variation is obtained with combustor outlet temperature adjustment, the efficiencies of the combined power plants with complex or Brayton cycle gas turbines, are substantially the same, for the same relative power variation.