bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quasi‐TEM Rectangular Waveguides with Frequency Selective Surface Walls: Part II—Physical Mechanism
Authors: Li Duochuan , Khaddaj Mallat Nazih , Wu Ke 
Published: December 2013

ABSTRACTThe physical mechanism of quasi‐TEM (transverse electromagnetic) waveguides with frequency selective surface (FSS) walls is established on the basis of an equivalent magnetic current technique in this paper. The equivalent magnetic current distributions in the slots of dielectric surfaces with dipole‐FSS walls and dielectric surface of bare‐slab, as well as hexagonal crystal FSS walls, are presented and discussed. This study shows that the electromagnetic fields in waveguide are mainly radiated from the concurrent magnetic current bands in longitudinal slots. The relationship between the uniformity of electromagnetic fields and the phase variation of longitudinal magnetic currents is discussed. The electrical properties and mechanism of quasi‐TEM rectangular waveguides with slotlines are also investigated to confirm the proposed mechanism. Three categories of periodic structure, which are potentially useful as artificial magnetic conductor, are investigated, and the required conditions to realize quasi‐TEM mode in rectangular waveguide are proposed. Copyright © 2013 John Wiley & Sons, Ltd.
Demography of Mexican spotted owls in the Sacramento Mountains, New Mexico
Authors: Ganey Joseph L. , White Gary C. , Ward James P. , Kyle Sean C. , Apprill Darrell L. , Rawlinson Todd A. , Jonnes Ryan S. 
Published: December 2013

ABSTRACTInformation on population dynamics is key to gauging the status of threatened or endangered species. We monitored demography of a population of threatened Mexican spotted owls (Strix occidentalis lucida) in the Sacramento Mountains, New Mexico from 2003 to 2011. We estimated reproductive output for territorial pairs of owls; used mark‐recapture methodology and Pradel's reparameterized Jolly‐Seber models to estimate annual apparent survival rates, recapture rates, recruitment rates, and annual rate of population change (λRJS) for 2005–2009; and used estimates of λRJS to assess short‐term population viability. Reproductive output was highly variable for 2004–2011, whereas annual apparent survival and recapture rates were less variable among years. Annual rates of population change exceeded 1.0 for both sexes from 2005 to 2009, and empirical observations of numbers of territorial owls supported the model‐based trend estimate. Abundance of territorial owls was strongly related to reproduction within the study area, suggesting that population change was driven largely by internal processes. Population viability analyses suggested that population growth was likely to continue in the short term if current conditions persist. The positive growth rates observed in our study populations are encouraging, and may indicate that current recommendations for recovering this owl are succeeding. However, our estimates of λRJS covered a very short time period, given both the potential lifespan of Mexican spotted owls and the extent of temporal variability in weather typical of the southwestern United States. Longer studies of owl demography than we present will be required to understand long‐term population trends, and such studies should extend across the range of the subspecies. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.
Optical frequency comb technology for ultra‐broadband radio‐frequency photonics
Authors: Torres‐Company Victor , Weiner Andrew M. 
Published: December 2013

AbstractThe outstanding phase‐noise performance of optical frequency combs has led to a revolution in optical synthesis and metrology, covering a myriad of applications, from molecular spectroscopy to laser ranging and optical communications. However, the ideal characteristics of an optical frequency comb are application dependent. In this review, the different techniques for the generation and processing of high‐repetition‐rate (>10 GHz) optical frequency combs with technologies compatible with optical communication equipment are covered. Particular emphasis is put on the benefits and prospects of this technology in the general field of radio‐frequency photonics, including applications in high‐performance microwave photonic filtering, ultra‐broadband coherent communications, and radio‐frequency arbitrary waveform generation.
Nanostructured Polymeric Functional Micelles for Drug Delivery Applications
Authors: Tripodo G. , Mandracchia D. , Dorati R. , Latrofa A. , Genta I. , Conti B. 
Published: December 2013

SummaryInulin (INU) is a polyfructose which have the unique features to not bind plasmatic proteins and to be totally filtered by the kidneys where it is neither secreted nor reabsorbed. These behaviors make it an ideal candidate to target and delivery drugs into the kidneys for the therapy of urinary tract affections. On the other side, Vitamin E (VITE) is a hydrophobic molecule with important antioxidant activities. Therefore, the chemical conjugation of INU and VITE, led to amphiphilic INVITE polymers able to self‐assemble in nanostructured micelle.The obtained micelle have been drug loaded with the model hydrophobic drug curcumin (solubility ≈ 11 ng/ml), the drug release and micelles stability studies have been performed in‐vitro in simulated physiological fluids. Furthermore, biological studies on suitable cell lines have been carried out to assess the cytotoxicity of INVITE conjugates.
Proliferation and Differentiation of Adipose Stem Cells Towards Smooth Muscle Cells on Poly(trimethylene carbonate) Membranes
Authors: German Salvador Jimenez , Behbahani Mehdi , Miettinen Susanna , Grijpma Dirk W. , Haimi Suvi P. 
Published: December 2013

SummaryMultipotent human adipose stem cells (hASCs) are an abundant and potential source of cells for vascular tissue engineering when combined with a suitable biomaterial scaffold. Poly(trimethylene carbonate) (PTMC) has been shown to be a useful biodegradable material for tissue engineered vascular grafts due to its flexibility, excellent biocompatibility and enzymatic degradation by surface erosion in vivo. The purpose of the current study was to evaluate the proliferation and differentiation of hASCs towards smooth muscle cells (SMCs) on gamma‐crosslinked and photo‐crosslinked PTMC membranes.PTMC macromers were functionalized with methacrylate end groups and crosslinked by UV initiated radical polymerization. High molecular weight linear PTMC was crosslinked by gamma irradiation. Cell viability, cell numbers and SMC differentiation of hASCs were evaluated on the differently crosslinked PTMC films at 7 and 14 days (d).On the photo‐crosslinked membranes, homogenous monolayers of hASC were detected by live/dead assay. Consistently, cells on the photo‐crosslinked membranes had significantly higher cell numbers compared to cells on the gamma‐crosslinked membranes after 14 d of culture. SMC specific genes were expressed on both membranes at 14 d. Photo‐crosslinked membranes showed higher expression of SMC specific proteins at 14 d compared to gamma‐crosslinked membranes.These results suggest that especially the photo‐crosslinked PTMC membranes are suitable for vascular tissue engineering applications when combined with hASCs.
Histological Evaluation of Degradable Guided Bone Regeneration Membranes Prepared from Poly(trimethylene carbonate) and Biphasic Calcium Phosphate Composites
Authors: Zeng Ni , van Leeuwen Anne , Bos Ruud R.M. , Grijpma Dirk W. , Kuijer Roel 
Published: December 2013

SummaryIn oral and maxillofacial surgery, guided bone regeneration using barrier membranes is an important strategy to treat bone defects. The currently used barrier membranes have important disadvantages. Barrier membranes prepared from resorbable poly(trimethylene carbonate) (PTMC) performed as well as collagen barrier membranes. We hypothesized that composite membranes prepared from surface‐eroding PTMC and osteoinductive biphasic calcium phosphate (BCP) would enhance bone formation even further. Bicortical critical size defects in the mandibular angle of rats were covered on both sides with the membranes. After 2, 4, and 12 weeks the extent of bone formation in the defects and the soft tissue reaction towards the membranes was examined histologically. At 2 and 4 weeks, the formation of new bone was observed in defects covered with PTMC, PTMC‐BCP and Biogide collagen membranes. At 12 weeks, bone defects that were covered with PTMC membranes and control Biogide collagen membranes were fully filled with new formed bone. However, at this time point, defects covered with PTMC‐BCP composite membranes had not led to new bone in the defects. Instead a significant tissue reaction, likely to remaining BCP particles, was observed.
Influence of Drying Procedures on Network Formation and Properties of Hydrogels from Functionalized Gelatin
Authors: Racheva Miroslava , Julich‐Gruner Konstanze K. , Nöchel Ulrich , Neffe Axel T. , Wischke Christian , Lendlein Andreas 
Published: December 2013

SummarySide chain functionalization of gelatin with tyrosine‐derived moieties, desaminotyrosine (DAT) or desaminotyrosyl tyrosine (DATT), has been reported to lead to physical networks stabilized by aromatic interactions and hydrogen bonds, while the inherent ability of gelatin chains to organize in helices is suppressed. Here, the treatment of DAT and DATT gelatin films at defined temperatures (drying at 5 °C, freeze‐drying, and freeze‐thawing) were explored for the potential to additionally stabilize the hydrogels by increasing the content of helical domains as additional physical netpoints. The influence of the drying procedures on the hydrogel properties such as network morphology and mechanical properties were analyzed by WAXS, swelling, and rheological measurements. The triple helix content had a stabilizing effect on gelatin‐based hydrogels at temperatures below the helix‐to‐coil transition. However, this effect was less pronounced at physiological conditions above the transition temperature, resulting in rapid dissolution of the physical gelatin networks.
Viscoelastic and thermal properties of polysulfide modified epoxy resin: The effect of modifier molecular weight
Authors: Farajpour T. , Bayat Y. , Keshavarz M. , Zanjirian E. 
Published: December 2013

AbstractIn this research two grades of polysulfide resin with low and high molecular weight (respectively G4 and G112) as reactive modifier was used to toughen epoxy resin. The effect of modifier molecular weight on impact resistance, thermal expansion coefficient, storage and loss modulus, decomposition temperature and adhesion properties of toughened epoxy was investigated. The impact strength and the thermal expansion coefficient (CTE) of epoxy resin was increased with increasing polysulfide but the G112 modified epoxy samples showed higher CTE values and impact resistance than those of modified with G4. Comparing of the same weight percent inclusion of G4 and G112 effect on decomposition temperature show that G4 modified epoxy resin has lower decomposition temperature than the G112 modified epoxy resin. Also addition of G112 up to 10 weight percent leads to higher bond strength with aluminum sheets. According to the DMTA graphs, glass transition temperature (Tg) of the modified epoxy was decreased with increasing polysulfide weight percent in composition. At the same time G4 modified epoxies have lower Tg and storage modulus than that of modified with G112.
Early retirement and non‐employment after breast cancer
Authors: Lindbohm M.‐L. , Kuosma E. , Taskila T. , Hietanen P. , Carlsen K. , Gudbergsson S. , Gunnarsdottir H. 
Published: December 2013

AbstractObjectiveThis study examined whether workplace support, sociodemographic factors and co‐morbidity are associated with early retirement or non‐employment due to other reasons among breast cancer survivors. We also compared quality of life and chronic symptoms (pain, fatigue, anxiety and depression) among employed, retired and other non‐employed breast cancer survivors.MethodsWe identified breast cancer survivors diagnosed between 1997 and 2002 from either a hospital or a cancer registry in Denmark, Finland, Iceland and Norway (NOCWO study). All patients had been treated with curative intent. Information on employment, co‐morbidity and support was collected via a questionnaire. The sample included 1111 working‐aged cancer‐free survivors who had been employed at the time of diagnosis. We used multinomial logistic regression models to analyse the association of various determinants with early retirement and other non‐employment (due to unemployment, subsidized employment or being a homemaker).ResultsLow education, low physical quality of life, co‐morbidity and pain were associated with both early retirement and other non‐employment after cancer. Other non‐employed survivors also rated their mental quality of life as lower and experienced anxiety and fatigue more often than all the other survivors. Moreover, they reported a lower level of supervisor support after their diagnosis than the employed survivors. Retired survivors more often reported weak support from colleagues.ConclusionsDifferences in ill health and functional status between various groups of non‐employed cancer survivors need to be considered when planning policy measures for improving the labour market participation of this population and preventing their early withdrawal from working life. Copyright © 2013 John Wiley & Sons, Ltd.
Winter climate change, plant traits and nutrient and carbon cycling in cold biomes
Authors: Cornelissen Johannes H. C. , Makoto Kobayashi 
Published: December 2013

AbstractIt is essential that scientists be able to predict how strong climate warming, including profound changes to winter climate, will affect the ecosystem services of alpine, arctic and boreal areas, and how these services are driven by vegetation–soil feedbacks. One fruitful avenue for studying such changing feedbacks is through plant functional traits, as an understanding of these traits may help us to understand and synthesise (1) responses of vegetation (through ‘response traits’ and ‘specific response functions’ of each species) to winter climate and (2) the effects of changing vegetation composition (through ‘effect traits’ and ‘specific effect functions’ of each species) on soil functions. It is the relative correspondence of variation in response and effect traits that will provide useful data on the impacts of winter climate change on carbon and nutrient cycling processes. Here we discuss several examples of how the trait‐based, response–effect framework can help scientists to better understand the effects of winter warming on key ecosystem functions in cold biomes. These examples support the view that measuring species for their response and effect traits, and how these traits are linked across species through correspondence of variation in specific response and effects functions, may be a useful approach for teasing out the contribution of changing vegetation composition to winter warming effects on ecosystem functions. This approach will be particularly useful when linked with ecosystem‐level measurements of vegetation and process responses to winter warming along natural gradients, over medium time scales in given sites or in response to experimental climate manipulations.
Rasch Trees: A New Method for Detecting Differential Item Functioning in the Rasch Model
Authors: Strobl Carolin , Kopf Julia , Zeileis Achim 
Published: December 2013

A variety of statistical methods have been suggested for detecting differential item functioning (DIF) in the Rasch model. Most of these methods are designed for the comparison of pre-specified focal and reference groups, such as males and females. Latent class approaches, on the other hand, allow the detection of previously unknown groups exhibiting DIF. However, this approach provides no straightforward interpretation of the groups with respect to person characteristics. Here, we propose a new method for DIF detection based on model-based recursive partitioning that can be considered as a compromise between those two extremes. With this approach it is possible to detect groups of subjects exhibiting DIF, which are not pre-specified, but result from combinations of observed covariates. These groups are directly interpretable and can thus help generate hypotheses about the psychological sources of DIF. The statistical background and construction of the new method are introduced by means of an instructive example, and extensive simulation studies are presented to support and illustrate the statistical properties of the method, which is then applied to empirical data from a general knowledge quiz. A software implementation of the method is freely available in the R system for statistical computing.
Reactive-infiltration instabilities in rocks. Part 2. Dissolution of a porous matrix
Authors: Szymczak Piotr , Ladd Anthony J. C. 
Published: December 2013

AbstractA reactive fluid dissolving a uniform porous material triggers an instability in the dissolution front, leading to spontaneous formation of pronounced well-spaced channels in the surrounding rock matrix. The concentration field within the dissolving region contains two different length scales, upstream (no reaction) and downstream of the front position. Previous investigations of the reactive-infiltration instability have considered one or other of the scales to be dominant, leading to rather different conclusions. Here we describe a more general linear stability analysis which includes both length scales simultaneously. We show how previous work corresponds to special cases of our more general analysis and obtain closed-form solutions for small permeability gradients.
Experimental study of a model valve with flexible leaflets in a pulsatile flow
Authors: Ledesma-Alonso R. , Guzmán J. E. V. , Zenit R. 
Published: December 2013

AbstractAn experimental investigation was conducted to study the dynamical behaviour of a model valve in a pulsatile flow. The valve is modelled as a pair of curved, rectangular, flexible leaflets that open and close under a time-periodic flow. Using image analysis, the range of flow parameters for which a valve (of a particular geometry and material properties of the leaflets) works correctly were identified. A correct performance was considered to be when the valve opened in one direction but blocked the flow in the reversed direction. A model is proposed to predict the performance of the valves. Furthermore, an analysis of fluid strains is conducted for valves that operate correctly to identify the influence of the valve’s design on fluid stresses. The main purpose of this investigation is to gain insight for the design of future prosthetic heart valves.
Ownership, resources, and business-group effects on affiliate performance: Evidence from Taiwan
Authors: Wang Chuan-Hung , Chu Wenyi , Chen Chien-Nan 
Published: December 2013

AbstractBusiness groups not only help affiliates circumvent market imperfections, but they also have great influence on the economic development of emerging markets. This study applies three ways to clarify the influence of business-group effects on affiliate performance. First, this study finds that the business group can explain a respectable portion of the variations in affiliate performance. Second, this study examines the impact of family ownership, resource abundance, and resource dispersion on affiliate performance and finds that group size and financial resources positively affect affiliate performance, while family ownership and group diversification do not have a significant effect on affiliate performance. Finally, the magnitude of business-group effects is subject to the ownership and resources of each business group. Family groups, large groups, and highly diversified groups have smaller business-group effects, while groups with high financial resources have greater business-group effects, indicating that business-group effects are heterogeneous and dependent on different group features. This study provides support to the resource-based and the institution-based views of business groups.
Customer participation and new product development outcomes: The moderating role of product innovativeness
Authors: Lin Ming-Ji James , Tu Yu-Cheng , Chen Der-Chao , Huang Chin-Hua 
Published: December 2013

AbstractInvestigation of customer participation in new product development (NPD) performance has yielded conflicting results. This study explores the idea that intensive customer participation is not always better. Instead, the usefulness of customer participation in NPD is determined by the fit between product innovativeness and customer participation as information providers and as co-developers. An empirical study of 196 NPD projects of Taiwanese high-tech firms is analyzed by structural equation modeling. The findings show that product innovativeness negatively moderates the impact of customer participation as information providers on NPD outcome. Thus, the greater the involvement of customer participation as information providers in radical innovation projects, the lower the NPD outcome. Moreover, our results also indicate that product innovativeness positively affects the relationship between customer participation as a co-developer and NPD outcome, which suggest that the more customer participation as a co-developer in a radical innovation project, the better the NPD outcome.
Introduction: Corporate Reputation in Historical Perspective
Authors: Olegario Rowena , McKenna Christopher 
Published: December 2013

“Corporate reputation” is a term that on the face of it hardly needs explanation. Historians have long used it in an unproblematic fashion to refer to the way a firm is perceived by others. Yet as with many such terms, corporate reputation can be theorized or at least formally defined. Scholars in the fields of marketing and organization increasingly are doing both; since the 1980s they have attempted to distinguish reputation from the related constructs of image, identity, status, legitimacy, celebrity, and brand equity. The project is ongoing, and a strong consensus has not yet been reached on how to define corporate reputation. Charles Fombrun, whose definitions have been perhaps the most widely used, suggests the following: “a collective assessment of a company's attractiveness to a specific group of stakeholders relative to a reference group of companies with which the company competes for resources.” Fombrun's definition contains three core ideas: firms have multiple reputations, depending on which stakeholders are being considered; corporate reputation is a comparative construct, because a firm is always judged in relation to something else—in this case, the firm's competitors; and firms' reputations are a source of competitive advantage or disadvantage.Historians, who for valid intellectual reasons rarely attempt the formal definition of terms, have not participated in the theorizing of corporate reputation. Yet the peculiar skills of historians are much needed; for if the study of corporate reputation has underemphasized the role of institutional phenomena such as rules, norms, processes, and structures, it has all but ignored historical context and historical processes.