bluuebunny/crossref_metadata_2025 huggingface dataset:
The economics of dentistry: a neglected concern
Authors: Shariati Batoul , MacEntee Michael I. , Yazdizadeh Maryam
Published: March 2013

Background

Demand for economic evaluations in health care is growing with expectations that they will help to develop regional and national policies on health and social programmes. We present here the scope, quality and content of systematic reviews and meta‐analyses relating to the economics of dentistry published over the last 15 years.

Objectives

To review the quality and outcome of systematic reviews and meta‐analyses relating to the economics of dental treatments, preventions and services.

Methods

A systematic search was conducted in 14 electronic databases for systematic reviews and meta‐analyses published betweenJanuary 1997 andJuly 2011 on the economics of oral disorders and oral health care. Review papers were extracted by two independent investigators to identify the characteristics, results and quality of the reviews and to highlight gaps in knowledge about the economics of dentistry.

Results

From 3150 unique references, we found 73 systematic reviews or meta‐analyses of dental economics as primary or secondary outcomes. The focus of 12 of them was on the cost or cost‐effectiveness of dental prevention, 54 on treatment, five on prevention and treatment and two on delivery of dental services. However, only 12 of the systematic reviews drew conclusions from economic data, and four of them constructed an economic model from synthesized data. Overall, the quality was good in the 12 systematic reviews but poor in the original studies.

Conclusions

There is very little helpful data published on the economics of dentistry.
Total thyroidectomy vs bilateral subtotal thyroidectomy in patients with Graves’ diseases: a meta‐analysis of randomized clinical trials
Authors: Guo Zhenying , Yu Peng , Liu Zhenjie , Si Yi , Jin Mingjuan
Published: March 2013

Background

Conducting total thyroidectomy (TT) or subtotal thyroidectomy (ST) in patients with Graves' disease remains controversial. We performed a meta‐analysis based on the published randomized controlled trials to evaluate the complications of TT vs ST.

Methods

We searched multiple electronic databases for prospective, randomized, controlled trials related to safety and effectiveness of TT vs ST. Relative risk (RR) was estimated with 95% confidence interval (CI) based on an intention‐to‐treat analysis. We considered the following outcomes: recurrent hyperthyroidism, ophthalmopathy progression, temporary and permanent hypoparathyroidism, temporary and permanent recurrent laryngeal nerve palsy (RLNP) and post‐operative bleeding.

Results

Four trials with 674 patients (342 with TT, 332 with ST) were analysed. Although the overall rates of ophthalmopathy progression were similar between TT and ST (RR 0·92, 95% CI = 0·50–1·71; P = 0·80), TT was associated with a significant reduction in recurrent hyperthyroidism (RR 0·14, 95% CI = 0·05–0·41; P < 0·01). The pooled RR of post‐operative bleeding for TT was similar to that for ST (RR 0·32, 95% CI = 0·05–1·96; P = 0·22). However, comparing with ST, the RR of temporary hypoparathyroidism was significantly higher for TT (RR 2·66, 95% CI = 1·89–3·73; P < 0·01). There was no significant difference in permanent hypoparathyroidism (RR 2·30, 95% CI = 0·78–6·76; P = 0·13), temporary (RR 1·08, 95% CI = 0·47–2·48; P = 0·85) and permanent RLNP (RR 1·54, 95% CI = 0·41–5·73; P = 0·52) between the two groups.

Conclusions

With regard to ophthalmopathy progression, post‐operative bleeding, permanent hypoparathyroidism, temporary and permanent RLNP, TT is consistent with ST in patients with Graves' disease. However, TT is associated with a reduced incidence of recurrent hyperthyroidism and results in an increase in temporary hypoparathyroidism. Therefore, TT should be proposed for the treatment of Graves' disease.
A family with fragile X syndrome, Duchenne muscular dystrophy and ichthyosis transmitted by an asymptomatic carrier
Authors: Todorova A. , Litvinenko I. , Todorov T. , Tincheva R. , Avdjieva D. , Tincheva S. , Mitev V.
Published: March 2013

The human X chromosome carries regions prone to genomic instability: deletions in the Xp22.31 region, involving the steroid sulfatase gene (STS) cause X‐linked ichthyosis; rearrangements in the Xp21.2 region are associated with Duchenne or Becker muscular dystrophies (DMD or BMD); and the Xq27.3 unstable region, containing the (CGG)n repeat expansion in the FMR1 gene is associated with fragile X syndrome. We report on a family with two affected boys, the elder diagnosed with fragile X syndrome, the younger with DMD, and both suffering from severe ichthyosis. The family was analyzed by polymerase chain reaction, multiplex ligation‐dependent probe amplification and haplotype analysis. The mother proved to be an asymptomatic carrier of all three non‐contiguous mutation events, involving the STS gene, the DMD gene and a FMR1 expansion. To the best of our knowledge, this is the first description of an asymptomatic carrier of three different X‐linked disorders, involving severe genetic rearrangements on both long and short arms of the X chromosomes. The boy with fragile X syndrome has inherited a triple recombinant maternal X chromosome, this way inheriting the FMR1 expansion and ichthyosis, originating most probably from different maternal Xes and excluding the DMD gene deletion. The transmission of these extremely defective maternal chromosomes to the next generation involved several recombinations.
Using Population Viability Criteria to Assess Strategies to Minimize Disease Threats for an Endangered Carnivore
Authors: DOAK DANIEL F. , BAKKER VICTORIA J. , VICKERS WINSTON
Published: March 2013

Outbreaks of infectious disease represent serious threats to the viability of many vertebrate populations, but few studies have included quantitative evaluations of alternative approaches to the management of disease. The most prevalent management approach is monitoring for and rapid response to an epizootic. An alternative is vaccination of a subset of the free‐living population (i.e., a “vaccinated core”) such that some individuals are partially or fully immune in the event of an epizootic. We developed a simulation model describing epizootic dynamics, which we then embedded in a demographic simulation to assess these alternative approaches to managing rabies epizootics in the island fox (Urocyon littoralis), a species composed of only 6 small populations on the California Channel Islands. Although the monitor and respond approach was superior to the vaccinated‐core approach for some transmission models and parameter values, this type of reactive management did not protect the population from rabies under many disease‐transmission assumptions. In contrast, a logistically feasible program of prophylactic vaccination for part of the wild population yielded low extinction probabilities across all likely disease‐transmission scenarios, even with recurrent disease introductions. Our use of a single metric of successful management—probability of extreme endangerment (i.e., quasi extinction)—to compare very different management approaches allowed an objective assessment of alternative strategies for controlling the threats posed by infectious disease outbreaks.

Utilización de Criterios de Viabilidad Poblacional para Evaluar Estrategias para Minimizar Amenazas de Enfermedades para un Carnívoro en Peligro
Assessing the Risk of Ships Striking Large Whales in Marine Spatial Planning
Authors: REDFERN J. V. , MCKENNA M. F. , MOORE T. J. , CALAMBOKIDIS J. , DEANGELIS M. L. , BECKER E. A. , BARLOW J. , FORNEY K. A. , FIEDLER P. C. , CHIVERS S. J.
Published: March 2013

Marine spatial planning provides a comprehensive framework for managing multiple uses of the marine environment and has the potential to minimize environmental impacts and reduce conflicts among users. Spatially explicit assessments of the risks to key marine species from human activities are a requirement of marine spatial planning. We assessed the risk of ships striking humpback (Megaptera novaeangliae), blue (Balaenoptera musculus), and fin (Balaenoptera physalus) whales in alternative shipping routes derived from patterns of shipping traffic off Southern California (U.S.A.). Specifically, we developed whale‐habitat models and assumed ship‐strike risk for the alternative shipping routes was proportional to the number of whales predicted by the models to occur within each route. This definition of risk assumes all ships travel within a single route. We also calculated risk assuming ships travel via multiple routes. We estimated the potential for conflict between shipping and other uses (military training and fishing) due to overlap with the routes. We also estimated the overlap between shipping routes and protected areas. The route with the lowest risk for humpback whales had the highest risk for fin whales and vice versa. Risk to both species may be ameliorated by creating a new route south of the northern Channel Islands and spreading traffic between this new route and the existing route in the Santa Barbara Channel. Creating a longer route may reduce the overlap between shipping and other uses by concentrating shipping traffic. Blue whales are distributed more evenly across our study area than humpback and fin whales; thus, risk could not be ameliorated by concentrating shipping traffic in any of the routes we considered. Reducing ship‐strike risk for blue whales may be necessary because our estimate of the potential number of strikes suggests that they are likely to exceed allowable levels of anthropogenic impacts established under U.S. laws.

Evaluación del Riesgo de Colisiones de Barcos y Ballenas en la Planificación Marina Espacial
Understanding Characteristics that Define the Feasibility of Conservation Actions in a Common Pool Marine Resource Governance System
Authors: Mills Morena , Pressey Robert L. , Ban Natalie C. , Foale Simon , Aswani Shankar , Knight Andrew T.
Published: March 2013

Effective conservation requires people to make choices about how they interact with the environment. Social characteristics influence the likelihood of establishing conservation actions with strong compliance (hereafter “feasibility”), but are rarely considered in conservation planning. Our study makes two contributions to understand feasibility. First, we explicitly test the associations between social characteristics and the presence and form of resource management. Second, we compare the ability of different types of data to elucidate feasibility. We use Ostrom's (2007) thinking on social–ecological systems and literature on resource management in Melanesia to create a context‐specific framework to identify social characteristics that influence feasibility for conservation management. We then apply this framework and test for associations between the presence and form of management on one hand and social characteristics on the other, using data collected at different resolutions. We found that conservation feasibility was associated with characteristics of the governance system, users, and the social, economic, and political setting. Villages with different forms of management were more similar to each other socially than to villages without management. Social data collected at the resolution of households accounted for over double the variation in the form and presence of management compared to data at the resolution of villages. Our methods can be adapted to conservation planning initiatives in other socioeconomic settings.
The evaluation of procedures for dyeing silk with buckthorn and walloon oak on the basis of colour changes and fastness characteristics
Authors: Deveoglu Ozan , Erkan Gokhan , Torgan Emine , Karadag Recep
Published: March 2013

In this study, silk fabric samples were dyed according to various procedures with buckthorn (Rhamnus petiolaris Boiss) and walloon oak (Quercus ithaburensis Decaisne) extracts. Reversed‐phase high‐performance liquid chromatography with diode‐array detection was utilised for the identification of dyes present in the dyed silk fabrics and the plant extracts. The extraction of dyes was carried out with a hydrochloric acid/methanol/water (2:1:1; v/v/v) mixture. The colour coordinates of the silk fabrics were measured, and the rubbing, wash and light fastness properties of the dyed silk materials were determined and are discussed.
The importance of water‐retaining features for biodiversity on artificial intertidal coastal defence structures
Authors: Firth Louise B. , Thompson Richard C. , White Freya J. , Schofield Meredith , Skov Martin W. , Hoggart Simon P. G. , Jackson Juliette , Knights Antony M. , Hawkins Stephen J.
Published: March 2013

Aim

Artificial coastal defence structures are proliferating in response to rising and stormier seas. These structures provide habitat for many species but generally support lower biodiversity than natural habitats. This is primarily due to the absence of environmental heterogeneity and water‐retaining features on artificial structures. We compared the epibiotic communities associated with artificial coastal defence structures and natural habitats to ask the following questions: (1) is species richness on emergent substrata greater in natural than artificial habitats and is the magnitude of this difference greater at mid than upper tidal levels; (2) is species richness greater in rock pools than emergent substrata and is the magnitude of this difference greater in artificial than natural habitats; and (3) in artificial habitats, is species richness in rock pools greater at mid than upper tidal levels?

Location

British Isles.

Methods

Standard non‐destructive random sampling compared the effect of habitat type and tidal height on epibiota on natural rocky shores and artificial coastal defence structures.

Results

Natural emergent substrata supported greater species richness than artificial substrata. Species richness was greater at mid than upper tidal levels, particularly in artificial habitats. Rock pools supported greater species richness than emergent substrata, and this difference was more pronounced in artificial than natural habitats. Rock pools in artificial habitats supported greater species richness at mid than upper tidal levels.

Main conclusions

Artificial structures support lower biodiversity than natural habitats. This is primarily due to the lack of habitat heterogeneity in artificial habitats. Artificial structures can be modified to provide rock pools that promote biodiversity. The effect of rock pool creation will be more pronounced at mid than upper tidal levels. The challenge now is to establish at what tidal height the effect of pools becomes negligible and to determine the rock pool dimensions for optimum habitat enhancement.
Working with Community Health Workers as ‘Volunteers’ in a Vaccine Trial: Practical and Ethical Experiences and Implications
Authors: Angwenyi Vibian , Kamuya Dorcas , Mwachiro Dorothy , Marsh Vicki , Njuguna Patricia , Molyneux Sassy
Published: March 2013

Community engagement is increasingly emphasized in biomedical research, as a right in itself, and to strengthen ethical practice. We draw on interviews and observations to consider the practical and ethical implications of involving Community Health Workers (CHWs) as part of a community engagement strategy for a vaccine trial on the Kenyan Coast. CHWs were initially engaged as an important network to be informed about the trial. However over time, and in response to community advice, they became involved in trial information sharing and identifying potential participants; thereby taking on roles that overlapped with those of employed fieldworkers (FWs). While CHWs involvement was generally perceived as positive and appreciated, there were challenges in their relations with FWs and other community members, partly related to levels and forms of remuneration. Specifically, payment of CHWs was not as high as for FWs and was based on ‘performance’. This extrinsic motivation had the potential to crowd out CHWs intrinsic motivation to perform their pre‐existing community roles. CHWs remuneration potentially also contributed to CHWs distorting trial information to encourage community members to participate; and to researchers encouraging CHWs to utilize their social connections and status to increase the numbers of people who attended information giving sessions. Individual consent processes were protected in this trial through final information sharing and consent being conducted by trained clinical staff who were not embedded in study communities. However, our experiences suggest that roles and remuneration of all front line staff and volunteers involved in trials need careful consideration from the outset, and monitoring and discussion over time.
Do thiazolidinediones still have a role in treatment of type 2 diabetes mellitus?
Authors: Consoli A. , Formoso G.
Published: March 2013

Thiazolidinediones have been introduced in the treatment of type 2 diabetes mellitus (T2DM) since the late 1990s. Although troglitazone was withdrawn from the market a few years later due to liver toxicity, both rosiglitazone and pioglitazone gained widespread use for T2DM treatment. In 2010, however, due to increased risk of cardiovascular events associated with its use, the European Medicines Agency recommended suspension of rosiglitazone use and the Food and Drug Administration severely restricted its use. Thus pioglitazone is the only thiazolidinedione still significantly employed for treating T2DM and it is the only molecule of this class still listed in the American Diabetes Association‐European Association for the Study of Diabetes 2012 Position Statement. However, as for the other thiazolidinediones, use of pioglitazone is itself limited by several side effects, some of them potentially dangerous. This, together with the development of novel therapeutic strategies approved in the last couple of years, has made it questionable whether or not thiazolidinediones (namely pioglitazone) should still be used in the treatment of T2DM. This article will attempt to formulate an answer to this question by critically reviewing the available data on the numerous advantages and the potentially worrying shortcomings of pioglitazone treatment in T2DM.
Winter host exploitation influences fitness traits in a parasitoid
Authors: Andrade Thiago Oliveira , Hervé Maxime , Outreman Yannick , Krespi Liliane , van Baaren Joan
Published: March 2013

Organisms can either evade winter's unfavourable conditions by migrating or diapausing, or endure them and maintain their activities. When it comes to foraging during winter, a period of scarce resources, there is strong selective pressure on resource exploitation strategy. Generalist parasitoids are particularly affected by this environmental constraint, as their fitness is deeply linked to the profitability of the available hosts. In this study, we considered a cereal aphid–parasitoid system and investigated (1) the host–parasitoid community structure, host availability, and parasitism rate in winter, (2) the influence of host quality in terms of species and instars on the fitness of the aphid parasitoid Aphidius rhopalosiphi De Stefani‐Perez (Hymenoptera: Braconidae: Aphidiinae), and (3) whether there is a detectable impact of host fidelity on parasitism success of this parasitoid species. Host density was low during winter and the aphid community consisted of the species Rhopalosiphum padi L. and Sitobion avenae Fabricius (both Hemiptera: Aphididae), both parasitized by A. rhopalosiphi at non‐negligible rates. Aphidius rhopalosiphi produced more offspring when parasitizing R. padi compared with S. avenae, whereas bigger offspring were produced when parasitizing S. avenae. Although aphid adults and old larvae were significantly larger hosts than young larvae, the latter resulted in higher emergence rates and larger parasitoids. No impact of host fidelity on emergence rates or offspring size was detected. This study provides some evidence that winter A. rhopalosiphi populations are able to take advantage of an array of host types that vary in profitability, indicating that host selectivity may drop under winter's unfavourable conditions.
Effects of polyacrylamide, biopolymer and biochar on the decomposition of 14C‐labelled maize residues and on their stabilization in soil aggregates
Authors: Awad Y. M. , Blagodatskaya E. , Ok Y. S. , Kuzyakov Y.
Published: March 2013

The efficacy of applying plant residues to agricultural soils as a carbon (C) source for microorganisms and C sequestration is dependent on soil physiochemical properties, which can be improved by aggregation using soil conditioners. However, no attempt has been made to assess the effects of soil conditioners such as biochar (BC), biopolymer (BP) or polyacrylamide (PAM) on plant residue decomposition. We assessed the effects of BC, synthesized BP and anionic PAM on the decomposition of 14C‐labelled maize residues and on their stabilization in aggregate fractions in sandy and sandy loam soils. Polyacrylamide and BP were applied at 400 kg ha−1 and BC was applied at 5000 kg ha−1, and the soils were incubated for 80 days at 22°C. The conditioners improved the physical and biological properties of both soils, as shown by a 24% increase in the 1–2 mm aggregates. Biochar and BP accelerated the decomposition of plant residues as indicated by 14CO2 efflux, and resulted in reduced stabilization of residues in both soils relative to that observed in the control and PAM treatments. The reduction in 14C incorporation and C stabilization in the BC‐ and BP‐treated soils was observed mainly in the < 0.25‐mm aggregates. This was confirmed by reduction of activity of hydrolytic enzymes (β‐cellobiosidase and β‐glucosidase). Decomposition of plant residues in sandy soil was more sensitive to BP and PAM application than that in sandy loam soil. Improved soil structure after applying BC and BP increased aeration and decreased the contact between plant residues and mineral soil particles and consequently accelerated plant residue decomposition and reduced C sequestration.
Simple pedotransfer functions to initialize reactive carbon pools of the RothC model
Authors: Weihermüller L. , Graf A. , Herbst M. , Vereecken H.
Published: March 2013

Modelling of carbon turnover is a widely used tool to estimate soil carbon stock changes as a response to climate and land‐use change. Carbon turnover models are increasingly used not only at the point scale but also at regional and continental scales, and the Rothamsted carbon model (RothC) is a widely used model because of its simplicity and easy implementation. For the initialization of the RothC model, knowledge about the carbon pool sizes is essential. Pool size characterization can be either obtained from physical fractionation or equilibrium model runs, but both approaches are time consuming and tedious, especially for larger scale simulations. In our study, a pedotransfer function (PTF) for the estimation of all active carbon pools of the RothC model is presented. As independent variables, only total organic carbon (TOC) and clay content, which are easily available at most scales, are necessary. For validation of PTFs the resistant plant material (RPM) stock estimated from physical fractionation of soil of a wide range of types was predicted with a R2 of 0.70. In a second step, associated errors induced by the use of PTFs were analysed by using simulation runs for a 100‐year time period. Thereafter, the model was either initialized by the carbon pools extracted from physical fractionation or the PTF. Maximum relative deviations in TOC content were small (<9%) and declined to <4% after 100 years. Further, absolute errors were within the range of measurement error for soil organic carbon. Therefore, we propose that PTFs can be used to initialize the RothC model whenever physical fractionation is not feasible or equilibrium runs are considered too tedious.
Chlorhexidine release from orthodontic adhesives after topical chlorhexidine treatment
Authors: Lim Bum‐Soon , Cheng Yanping , Lee Seung‐Pyo , Ahn Sug‐Joon
Published: March 2013

This study was designed to investigate the ability of orthodontic adhesives to adsorb and release chlorhexidine (CHX) after periodic treatment with 1% CHX solution. Composite and resin‐modified glass‐ionomer cement (RM‐GIC) adhesive disks were incubated with whole saliva or distilled water for 2 h. Release of CHX was measured using high‐performance liquid chromatography after 1, 2, and 5 d of incubation, 1 min after exposure to 1% CHX solution. The CHX measurements were performed in a 5‐d cycle, which was repeated four consecutive times (n = 7). The amount of CHX adsorbed and the cumulative amounts of CHX released, with respect to type of adhesive and saliva‐coating, were analyzed using repeated‐measures anova. Chlorhexidine‐adsorbed orthodontic adhesives demonstrated a short‐term release of CHX, which rapidly returned to near‐baseline levels within 3 d. Saliva‐coating did not significantly influence CHX release from RM‐GIC, but increased the amount of CHX released from the composite. The amount of CHX released from the composite was 20‐fold higher than that released from the RM‐GIC after saliva‐coating. The composite adhesive showed a greater adsorption capacity for CHX than did the RM‐GIC, which was more evident after saliva‐coating. This study suggests that composite adhesives may be a significantly more effective CHX reservoir than RM‐GICs in the oral cavity filled with saliva.
The Effects of Perceived Control on Venture Capitalist Investment Decisions: A Configurational Perspective
Authors: Drover Will , Wood Matthew S. , Payne G. Tyge
Published: March 2013

Drawing on agency and configurations theories, this study examines how perceived level of control over the entrepreneur influences venture capitalist (VC) decision making. We model the direct effects of perceived control and the interactive effects of control with entrepreneurial prestige and opportunity attractiveness to determine how various combinations of factors influence VCs’ willingness to invest. We test our conceptualizations using conjoint analyses of 552 VC investment decisions. The results show that perceived control is directly related to investment likelihood, but different configurations of control, entrepreneur prestige, and opportunity attractiveness result in different outcomes. Our findings support a configurational perspective of VC decision making.
On the Theory of Entrepreneurial Incentives and Alertness
Authors: McCaffrey Matthew
Published: March 2013

This paper analyzes the theory of “entrepreneurial incentives” in the work of Israel Kirzner. It argues that there is a logical problem with the notion of profit opportunities as exogenous causal agents: Without additional assumptions, the existence of opportunities alone does not sufficiently explain the alertness of entrepreneurs. The paper considers both stronger and weaker versions of this problem. It also questions the relation between entrepreneurial incentives and the tendency toward entrepreneurial success. Finally, it provides some commentary on the relevance of entrepreneurial incentives for an overall theory of the entrepreneur, and identifies several potential solutions to the problems discussed.
Boundaries of Social Capital in Entrepreneurship
Authors: Light Ivan , Dana Léo–Paul
Published: March 2013

Our research begins with a theoretical critique of the social capital literature, and then focuses on Old Harbor, Alaska. In this remote outpost, mainly populated by Alutiiq people, all entrepreneurs self–identified as Euro–Americans or multi–ethnic, not Alutiiq. Although Alutiiq people have abundant social capital, which they employed for economic purposes, they did not employ their social capital for commercial entrepreneurship. Our findings suggest that social capital promotes entrepreneurship only when supportive cultural capital is in place.
National Rates of Opportunity Entrepreneurship Activity: Insights from Institutional Anomie Theory
Authors: Cullen John B. , Johnson Jean L. , Parboteeah K. Praveen
Published: March 2013

We advance and test an institutional anomie theory of opportunity entrepreneurship for understanding the combinative effects of selected cultural values and social institutions to explain national differences in rates of opportunity entrepreneurship. We theorize opportunity entrepreneurship as a creatively deviant response to anomic conditions in societies, i.e., when social institutions block traditional means of achievement. Using 10 years of data for a pooled time series cross–sectional analysis, we examined a unique mixture of cultural and institutional variables and their interactions as predictors of nation–level opportunity entrepreneurship rates. We found support for most hypotheses showing that specific institutional contexts mitigate or enhance the effects of cultural drivers of opportunity entrepreneurship.
Wham–O's Offer to Buy Sprig Toys: Selling in or Selling Out?
Authors: Sarason Yolanda , DeTienne Dawn R. , Bentley Catherine
Published: March 2013

Sprig Toy's mission was to deliver eco–friendly, battery–free, paint–free, kid–powered toys. The company had seen a meteoric rise since its beginning in 2007. Now, however, the founders were at a crossroads. They needed an immediate influx of capital, and on the table was a purchase offer from Wham–O®. As social entrepreneurs, their decision was not purely financial. They had wanted to start a company that would change both the market (how kids played) and the industry (how toys were manufactured)—but now, they had to make a decision regarding the offer to buy their company, and they worried whether they were “selling out.”
Entrepreneurial Behavior of Academic Scientists: Network and Cognitive Determinants of Commitment to Grant Submissions and Award Outcomes
Authors: Haller Megan K. , Welch Eric W.
Published: March 2013

We employ the individual–opportunity nexus perspective to conceptualize entrepreneurial commitment of academic scientists as the pursuit and attainment of external grant funding. We develop and test a model of network characteristics and cognitive biases that predict the likelihood that scientists will commit to a grant opportunity and the likelihood of receiving an award. Using data from our national survey of faculty, we find that the illusion of control and overconfidence reduce grant submissions but increase awards. Collaboration network size increases submissions and awards. Strong ties are positively related to submissions and smaller networks of strong, highly capable collaborators receive more awards.
A Signaling Perspective on Partner Selection in Venture Capital Syndicates
Authors: Hopp Christian , Lukas Christian
Published: March 2013

This paper analyzes the factors impacting partnering decisions in venture capital syndicates using a unique data set of 2,373 venture capitalist (VC) transactions in Germany. We employ a signaling perspective to partner–selection strategies within VC syndicates. By including time–varying information about industry experience and cooperation patterns, we explicitly take into account not only the changing social context for partner selection, but also the dynamic nature of signals sent and received. Our analysis documents that the informativeness of investment experience as a signal depends on the existence and frequency of previous joint deals with the lead VC. Experience becomes a much stronger signal if previous invitations to syndicates are bilateral rather than unilateral. The willingness to invite others to deals signals the ability to reciprocate through one's own deal flow. Moreover, we show how the value of signals erodes over time, that is, information from the previous year carries more informational value than signals from more distant years. In sum, the data reveal that different signals carry weight for lead VCs, and that the frequency of signals sent and the stage of development of the portfolio firm positively moderate the value and relevance of signaling behavior. While early stage investments are mainly characterized by need to diversify and to spread risks, value–added advice is necessary in later rounds, and hence, the strength of the signals sent and received gain in relevance and in value.
The Knowledge Spillover Theory of Entrepreneurship in Alliances
Authors: Shu Chengli , Liu Cuijuan , Gao Shanxing , Shanley Mark
Published: March 2013

We develop and examine a framework for the knowledge spillover theory of entrepreneurship in alliances. Our framework regards entrepreneurial opportunity as endogenous, and entrepreneurial firms as heterogeneous. The empirical findings show that partners’ knowledge protection, which is regarded as a knowledge filter, can increase knowledge spillovers in an alliance. Moreover, this relationship is contingent on the strength of a focal firm's entrepreneurial orientation and on alliance type (equity joint venture versus nonequity joint venture). Results also reveal that knowledge spillovers in an alliance enhance alliance performance more significantly than they enhance firm performance.
International Entrepreneurial Orientation: Conceptual Considerations, Research Themes, Measurement Issues, and Future Research Directions
Authors: Covin Jeffrey G. , Miller Danny
Published: March 2013

The amount of research conducted on the topic of international entrepreneurial orientation (IEO) has grown exponentially in recent years, thus inviting an analysis of the scholarly conversations taking place. This paper is a review and commentary on how the construct of entrepreneurial orientation (EO) has been leveraged within the international entrepreneurship literature. The possible distinctiveness of the EO and IEO constructs are considered, and the major themes of IEO research are summarized. Several measurement–related issues particularly pertinent to the assessment of EO as a generalizable/universalistic phenomenon are considered. The paper concludes with the identification of research foci whose pursuit promises to advance IEO knowledge along productive paths.
Bureaucratic Systems’ Facilitating and Hindering Influence on Social Capital
Authors: Saparito Patrick A. , Coombs Joseph E.
Published: March 2013

This study demonstrates how banks’ bureaucratic systems (i.e., formalization, management continuity, customer orientation) are associated with social capital's relational and cognitive dimensions. We collected survey data from a matched sample of 884 small– and medium–sized enterprises (SME) executives and 217 bank managers across 22 banks to test hypothesized relationships. Our results showed that formalization is negatively associated with both dimensions of social capital, while management continuity and customer orientation are positively associated with them. These results are a first step in answering calls in the literature to study bureaucratic systems’ influence on social capital. Theoretical and future research implications are discussed.
Potential role ofFoxO1 and mTORC1 in the pathogenesis ofWestern diet‐induced acne
Authors: Melnik Bodo C. , Zouboulis Christos C.
Published: March 2013

Acne in adolescents of developed countries is an epidemic skin disease and has currently been linked to theWestern diet (WD). It is the intention of this viewpoint to discuss the possible impact ofWD‐mediated nutrient signalling in the pathogenesis of acne. High glycaemic load and dairy protein consumption both increase insulin/insulin‐like growth factor‐1 (IGF‐1) signalling (IIS) that is superimposed on elevatedIGF‐1 signalling of puberty. The cell's nutritional status is primarily sensed by the forkhead box transcription factorO1 (FoxO1) and the serine/threonine kinase mammalian target of rapamycin complex 1 (mTORC1). IncreasedIISextrudesFoxO1 into the cytoplasm, whereas nuclearFoxO1 suppresses hepaticIGF‐1 synthesis and thus impairs somatic growth.FoxO1 attenuates androgen signalling, interacts with regulatory proteins important for sebaceous lipogenesis, regulates the activity of innate and adaptive immunity, antagonizes oxidative stress and most importantly functions as a rheostat of mTORC1, the master regulator of cell growth, proliferation and metabolic homoeostasis. Thus,FoxO1 links nutrient availability to mTORC1‐driven processes: increased protein and lipid synthesis, cell proliferation, cell differentiation including hyperproliferation of acroinfundibular keratinocytes, sebaceous gland hyperplasia, increased sebaceous lipogenesis, insulin resistance and increased body mass index. Enhanced androgen,TNF‐α andIGF‐1 signalling due to genetic polymorphisms promoting the risk of acne all converge in mTORC1 activation, which is further enhanced by nutrient signalling ofWD. Deeper insights into the molecular interplay ofFoxO1/mTORC1‐mediated nutrient signalling are thus of critical importance to understand the impact ofWDon the promotion of epidemic acne and more serious mTORC1‐driven diseases of civilization.
Ambient assisted living system with capacitive occupancy sensor
Authors: Fernandez‐Luque Francisco J. , Martínez Félix L. , Domènech Ginés , Zapata Juan , Ruiz Ramón
Published: March 2013

Alert intelligent device is an ambient assisted living (AAL) system that allows the evaluation of potentially dangerous situations for elderly people living alone at home. This evaluation is obtained by an ad hoc network of sensor nodes, working in conjunction with an ambient intelligence layer embedded in a personal computer that learns from user behaviour patterns and warns when a detected pattern differs significantly from previously acquired normal patterns. Each new datum read from sensors is processed in the ambient intelligence layer through three processing levels: shallow, intermediate and deep. The shallow processing level focuses on physical data and sensory features. The intermediate level covers information interpretation and its translation into the form required by the third level: the reasoning processing or deep level.

In alert intelligent device, energy is a critical issue, so that sensor devices need to be properly designed and managed to achieve significant energy saving. The use of bed/chair occupancy sensors is mandatory for this kind of ubiquitous computing system. A first way to approach this problem relied on the use of pressure mats, but several environmental drawbacks showed them inappropriate as an efficient and reliable solution for large volume deployments. Moreover, solutions based on force‐to‐resistor transducers entail power consumption budgets that keep them from being integrated on wireless sensor nodes. In this paper, a force‐capacitive transducer based sensor has been proposed, implemented and tested. This sensor is based on electromechanical film (EMFi) transducers, which are able to detect force variations in a quasi‐passive way. This kind of transducer behaves as capacitors with variable capacitance depending on the force exerted on its surface. We have developed a new technique to carry out the characterization of these transducers, where the detection of a force change is used to trigger an active mechanism that allows us to measure the weight by means of a novel modelling approach. A low‐power wireless sensor node prototype that includes this new transducer has been assembled and tested on a wide range of weights. Occupancy detection achieved by this technology has proven to be successful, increasing the total power consumption of the node by less than 15%, which makes it suitable for implementation.
Biotic and abiotic controls on body size during critical life history stages of a pelagic fish, Pacific herring (Clupea pallasii)
Authors: Reum Jonathan C. P. , Essington Timothy E. , Greene Correigh M. , Rice Casimir A. , Polte Patrick , Fresh Kurt L.
Published: March 2013

Variation in growth and body size during critical life history stages can have important implications for life history schedules and survivorship. For Pacific herring (Clupea pallasii), there is still debate as to whether juvenile body size is governed by density‐dependent or ‐independent processes and few have evaluated whether the relative importance of either process shifts over the course of early ontogeny. We used a unique data set consisting of seasonal measurements of abundance, body size, and spatial distribution within a semi‐enclosed basin of Puget Sound (Washington State, U.S.A.) to measure the relative importance of temperature and cohort abundance on body size at distinct time periods, and evaluated whether density‐dependent habitat shifts might be responsible for density‐dependent growth. Over the 9 years of sampling (2001–2010) midsummer body size was positively related to temperatures experienced during the egg/yolk sac and larval stages and unrelated to cohort abundance. However, fall body size was negatively correlated with abundance and uncorrelated with both midsummer body size and temperature, indicating a shift from density‐independent to density‐dependent control over the course of the growing season. Thus, density‐dependent effects may supplant density‐independent effects exhibited early in herring life history. Our data on spatial distributions of herring and their zooplankton prey indicate that density‐dependent reductions in growth may be explained by density‐dependent habitat shifts that lead to reduce overlap of herring with zooplankton. Evidence of density‐dependent growth in marine fish populations is often attributed to exploitative competition, but our results suggest that these patterns may partly be mediated by density‐dependent distribution expansions in to prey‐poor habitat.
Does dissolved organic carbon regulate biological methane oxidation in semiarid soils?
Authors: Sullivan Benjamin W. , Selmants Paul C. , Hart Stephen C.
Published: March 2013

In humid ecosystems, the rate of methane (CH4) oxidation by soil‐dwelling methane‐oxidizing bacteria (MOB) is controlled by soil texture and soil water holding capacity, both of which limit the diffusion of atmospheric CH4 into the soil. However, it remains unclear whether these same mechanisms control CH4 oxidation in more arid soils. This study was designed to measure the proximate controls of potential CH4 oxidation in semiarid soils during different seasons. Using a unique and well‐constrained 3‐million‐year‐old semiarid substrate age gradient, we were able to hold state factors constant while exploring the relationship between seasonal potential CH4 oxidation rates and soil texture, soil water holding capacity, and dissolved organic carbon (DOC). We measured unexpectedly higher rates of potential CH4 oxidation in the wet season than the dry season. Although other studies have attributed low CH4 oxidation rates in dry soils to desiccation of MOB, we present several lines of evidence that this may be inaccurate. We found that soil DOC concentration explained CH4 oxidation rates better than soil physical factors that regulate the diffusion of CH4 from the atmosphere into the soil. We show evidence that MOB facultatively incorporated isotopically labeled glucose into their cells, and MOB utilized glucose in a pattern among our study sites that was similar to wet‐season CH4 oxidation rates. This evidence suggests that DOC, which is utilized by MOB in other environments with varying effects on CH4 oxidation rates, may be an important regulator of CH4 oxidation rates in semiarid soils. Our collective understanding of the facultative use of DOC by MOB is still in its infancy, but our results suggest it may be an important factor controlling CH4 oxidation in soils from dry ecosystems.
Persistent versus transient tree encroachment of temperate peat bogs: effects of climate warming and drought events
Authors: Heijmans Monique M. P. D. , van der Knaap Yasmijn A. M. , Holmgren Milena , Limpens Juul
Published: March 2013

Peatlands store approximately 30% of global soil carbon, most in moss‐dominated bogs. Future climatic changes, such as changes in precipitation patterns and warming, are expected to affect peat bog vegetation composition and thereby its long‐term carbon sequestration capacity. Theoretical work suggests that an episode of rapid environmental change is more likely to trigger transitions to alternative ecosystem states than a gradual, but equally large, change in conditions. We used a dynamic vegetation model to explore the impacts of drought events and increased temperature on vegetation composition of temperate peat bogs. We analyzed the consequences of six patterns of summer drought events combined with five temperature scenarios to test whether an open peat bog dominated by moss (Sphagnum) could shift to a tree‐dominated state. Unexpectedly, neither a gradual decrease in the amount of summer precipitation nor the occurrence of a number of extremely dry summers in a row could shift the moss‐dominated peat bog permanently into a tree‐dominated peat bog. The increase in tree biomass during drought events was unable to trigger positive feedbacks that keep the ecosystem in a tree‐dominated state after a return to previous ‘normal’ rainfall conditions. In contrast, temperature increases from 1 °C onward already shifted peat bogs into tree‐dominated ecosystems. In our simulations, drought events facilitated tree establishment, but temperature determined how much tree biomass could develop. Our results suggest that under current climatic conditions, peat bog vegetation is rather resilient to drought events, but very sensitive to temperature increases, indicating that future warming is likely to trigger persistent vegetation shifts.
Evolutionary refugia and ecological refuges: key concepts for conserving Australian arid zone freshwater biodiversity under climate change
Authors: Davis Jenny , Pavlova Alexandra , Thompson Ross , Sunnucks Paul
Published: March 2013

Refugia have been suggested as priority sites for conservation under climate change because of their ability to facilitate survival of biota under adverse conditions. Here, we review the likely role of refugial habitats in conserving freshwater biota in arid Australian aquatic systems where the major long‐term climatic influence has been aridification. We introduce a conceptual model that characterizes evolutionary refugia and ecological refuges based on our review of the attributes of aquatic habitats and freshwater taxa (fishes and aquatic invertebrates) in arid Australia. We also identify methods of recognizing likely future refugia and approaches to assessing the vulnerability of arid‐adapted freshwater biota to a warming and drying climate. Evolutionary refugia in arid areas are characterized as permanent, groundwater‐dependent habitats (subterranean aquifers and springs) supporting vicariant relicts and short‐range endemics. Ecological refuges can vary across space and time, depending on the dispersal abilities of aquatic taxa and the geographical proximity and hydrological connectivity of aquatic habitats. The most important are the perennial waterbodies (both groundwater and surface water fed) that support obligate aquatic organisms. These species will persist where suitable habitats are available and dispersal pathways are maintained. For very mobile species (invertebrates with an aerial dispersal phase) evolutionary refugia may also act as ecological refuges. Evolutionary refugia are likely future refugia because their water source (groundwater) is decoupled from local precipitation. However, their biota is extremely vulnerable to changes in local conditions because population extinction risks cannot be abated by the dispersal of individuals from other sites. Conservation planning must incorporate a high level of protection for aquifers that support refugial sites. Ecological refuges are vulnerable to changes in regional climate because they have little thermal or hydrological buffering. Accordingly, conservation planning must focus on maintaining meta‐population processes, especially through dynamic connectivity between aquatic habitats at a landscape scale.