We examine whether the likelihood of entrepreneurial activity is related to the prior career experiences of an individual's coworkers, using a unique matched employer-employee panel data set. We ...argue that coworkers can increase the likelihood that an individual will perceive entrepreneurial opportunities as well as increase his or her motivation to pursue those opportunities. We find that an individual is more likely to become an entrepreneur if his or her coworkers have been entrepreneurs before. Peer influences also appear to be substitutes for other sources of entrepreneurial influence: we find that peer influences are strongest for those who have less exposure to entrepreneurship in other aspects of their lives.
Using a study of the relationship between bureaucratic work environments and individual rates of entrepreneurship, I revisit a fundamental premise of sociological approaches to entrepreneurship, ...namely, that the social context shapes the likelihood of entrepreneurial activity, above and beyond any effects of individual characteristics. Establishing such contextual effects empirically is complicated by the possibility that unobserved individual traits influence both the contexts in which people are observed and their likelihood of becoming entrepreneurs. This paper presents the first systematic study of the effects of bureaucracy on entrepreneurship that accounts for such unobserved sorting processes. Analyses of data on labor market attachments and transitions to entrepreneurship in Denmark between 1990 and 1997 show that people who work for large and old firms are less likely to become entrepreneurs, net of a host of observable individual characteristics. Moreover, there is strong evidence to suggest that this negative effect of bureaucracy does not spuriously reflect self-selection by nascent entrepreneurs into different types of firms. An important implication of this finding is that the structure of organizational populations affects the supply of nascent entrepreneurs, as well as the availability of entrepreneurial opportunities.
Why do humans form groups? Why would a brain, preoccupied with predicting the world, make the formation of cultures possible? And how does our socio-historical context shape the way we think?In a ...world faced with numerous global challenges and burdened by conflicts defined along cultural boundaries, now more than ever we need a comprehensive theory of the role of culture in human cooperation. Cultures persist: not only because they enable coordination and cooperation between otherwise selfinterested individuals, but because they cultivate our minds to make us grasp and sense the world in a particular manner, creating enduring structures of mutual solidarity based on a shared experience of reality.But cultures are not static: they evolve. As we endeavor to predict and classify the spheres of interaction in which we participate, culture falls into place and can be seen to function much like an immune system. If we are to understand the resilience of cultural groups and the evolution of the human mind, we need only look inside ourselves, to our predictive brain and to the immune system regulating the interaction across borders of both cells and cultures. Alongside our natural immune system, humans are endowed with cultural immune systems that bestow individuals and groups alike with resilience and adaptability.This book is a call for the formation of a genuine cultural immunology.In this erudite and compelling work Sørensen tackles the problem of why and how humans congregate in groups of various sizes, small and very large, apparently held together only by highly abstract concepts such as ideologies or religious beliefs. The simple answer would be “culture provides the glue". Sørensen does not settle for simplicity. He proposes with powerful arguments that we look to how the immune system works and then employ this knowledge analogically to the problem at hand. The analysis is nothing short of brilliant! You will find out how the predictive capacity of humans plays a fundamental explanatory role. Read this book and be edified!E. Thomas Lawson, Editor of Journal of Cognition and CultureJesper Sørensen is Associate Professor of Comparative Religion and co-founder of the Religion, Culture and Cognition research group at Aarhus University. He has published widely on magic, divination, ritual, cognitive historiography, and theory of culture and religion.
Normalization of target gene expression, measured by real-time quantitative PCR (qPCR), is a requirement for reducing experimental bias and thereby improving data quality. The currently used ...normalization approach is based on using one or more reference genes. Yet, this approach extends the experimental work load and suffers from assumptions that may be difficult to meet and to validate.
We developed a data driven normalization algorithm (NORMA-Gene). An analysis of the performance of NORMA-Gene compared to reference gene normalization on artificially generated data-sets showed that the NORMA-Gene normalization yielded more precise results under a large range of parameters tested. Furthermore, when tested on three very different real qPCR data-sets NORMA-Gene was shown to be best at reducing variance due to experimental bias in all three data-sets compared to normalization based on the use of reference gene(s).
Here we present the NORMA-Gene algorithm that is applicable to all biological and biomedical qPCR studies, especially those that are based on a limited number of assayed genes. The method is based on a data-driven normalization and is useful for as little as five target genes comprising the data-set. NORMA-Gene does not require the identification and validation of reference genes allowing researchers to focus their efforts on studying target genes of biological relevance.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Entrepreneurship as a Mobility Process Sørensen, Jesper B.; Sharkey, Amanda J.
American sociological review,
04/2014, Letnik:
79, Številka:
2
Journal Article
Recenzirano
We advance a theory of how organizational characteristics, in particular the structure of opportunity within organizations, shape the decision to become an entrepreneur. Established organizations ...play an important yet understudied role in the entrepreneurial process, because they shape the environment within which individuals may choose to enter self-employment. Yet, despite the fact that sociologists have long recognized that inequality within organizations plays an important role in career attainment and mobility, we lack an understanding of how it shapes the pursuit of entrepreneurial opportunities. We develop a formal model in which entrepreneurial choice is driven by differences in the arrival rate of various types of advancement opportunities. Entrepreneurship then arises as a result of matching processes between workers and employers, as well as the features of opportunity structures in paid employment. Analyses using Danish census data provide support for empirical implications derived from the model.
The interplay between theory and method Van Maanen, John; Sørensen, Jesper B.; Mitchell, Terence R.
The Academy of Management review,
10/2007, Letnik:
32, Številka:
4
Journal Article
Recenzirano
This Special Topic Forum on The Interplay Between Theory and Method contains six papers that collectively address a variety of quite practical and little addressed research process questions - from ...design to data collection to analysis to presentation. Individually, the papers explore how theory and method inevitably interact in particular organization and management studies and are best thought of as highly intertwined rather than conceptually independent. In this introduction, we offer an overview of how theory and method have been treated to date by organization researchers and suggest that respecting both the primacy of theory and the primacy of evidence is no easy task but a necessary balancing practice that characterizes high quality research. What constitutes good or useful theory (or methods) in the field remains up in the air and will differ by readers from distinct research communities and cannot be resolved through empirical validation (or theoretical advances) alone. PUBLICATION ABSTRACT
Organizations as Fonts of Entrepreneurship Sørensen, Jesper B.; Fassiotto, Magali A.
Organization science (Providence, R.I.),
09/2011, Letnik:
22, Številka:
5
Journal Article
Recenzirano
Most entrepreneurs emanate from established organizations, yet systematic theorizing about the ways in which organizations shape the entrepreneurial process has only recently begun to emerge. We ...provide a framework for organizing this emerging literature. We focus on four different metaphors in the literature for how organizations matter in the entrepreneurial process and suggest promising avenues for future research.
The widespread agricultural and industrial emissions of copper-based chemicals have increased copper levels in soils worldwide. Copper contamination can cause a range of toxic effects on soil animals ...and influence thermal tolerance. However, toxic effects are commonly investigated using simple endpoints (e.g., mortality) and acute tests. Thus, how organisms respond to ecological realistic sub-lethal and chronic exposures across the entire thermal scope of an organism is not known. In this study, we investigated the effects of copper exposure on the thermal performance of a springtail (Folsomia candida), regarding its survival, individual growth, population growth, and the composition of membrane phospholipid fatty acids. Folsomia candida (Collembola) is a typical representative of soil arthropods and a model organism that has been widely used for ecotoxicological studies. In a full-factorial soil microcosm experiment, springtails were exposed to three levels of copper (ca. 17 (control), 436, and 1629 mg/kg dry soil) and ten temperatures from 0 to 30 °C. Results showed that three-week copper exposure at temperatures below 15 °C and above 26 °C negatively influenced the springtail survival. The body growth was significantly lower for the springtails in high-dose copper soils at temperatures above 24 °C. A high copper level reduced the number of juveniles by 50 %, thereby impairing population growth. Both temperature and copper exposure significantly impacted membrane properties. Our results indicated that high-dose copper exposure compromised the tolerance to suboptimal temperatures and decreased maximal performance, whereas medium copper exposure partially reduced the performance at suboptimal temperatures. Overall, copper contamination reduced the thermal tolerance of springtails at suboptimal temperatures, probably by interfering with membrane homeoviscous adaptation. Our results show that soil organisms living in copper-contaminated areas might be more sensitive to thermally stressful periods.
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•Extensive use of copper-based products in agriculture and industry calls for in-depth risk assessment.•Global warming will exacerbate toxicity of heavy metals on soil invertebrates.•Cu pollution shifted the thermal performance curve and reduced thermal tolerance of springtails by damaging cell membranes.
Analysis of macromolecular/small-molecule binding pockets can provide important insights into molecular recognition and receptor dynamics. Since its release in 2011, the POVME (POcket Volume ...MEasurer) algorithm has been widely adopted as a simple-to-use tool for measuring and characterizing pocket volumes and shapes. We here present POVME 2.0, which is an order of magnitude faster, has improved accuracy, includes a graphical user interface, and can produce volumetric density maps for improved pocket analysis. To demonstrate the utility of the algorithm, we use it to analyze the binding pocket of RNA editing ligase 1 from the unicellular parasite Trypanosoma brucei, the etiological agent of African sleeping sickness. The POVME analysis characterizes the full dynamics of a potentially druggable transient binding pocket and so may guide future antitrypanosomal drug-discovery efforts. We are hopeful that this new version will be a useful tool for the computational- and medicinal-chemist community.
The thermal biology of ectotherms is often used to infer species' responses to changes in temperature. It is often proposed that temperate species are more cold-tolerant, less heat-tolerant, more ...plastic, have broader thermal performance curves (TPCs) and lower optimal temperatures when compared to tropical species. However, relatively little empirical work has provided support for this using large interspecific studies. In the present study, we measure thermal tolerance limits and thermal performance in 22 species of Drosophila that developed under common conditions. Specifically, we measure thermal tolerance (CT
and CT
) as well as the fitness components viability, developmental speed and fecundity at seven temperatures to construct TPCs for each of these species. For 10 of the species, we also measure thermal tolerance and thermal performance following developmental acclimation to three additional temperatures. Using these data, we test several fundamental hypotheses about the evolution and plasticity of heat and cold resistance and thermal performance. We find that cold tolerance (CT
) varied between the species according to the environmental temperature in the habitat from which they originated. These data support the idea that the evolution of cold tolerance has allowed species to persist in colder environments. However, contrary to expectation, we find that optimal temperature ( T
) and the breadth of thermal performance ( T
) are similar in temperate, widespread and tropical species and we also find that the plasticity of TPCs was constrained. We suggest that the temperature range for optimal thermal performance is either fixed or under selection by the more similar temperatures that prevail during growing seasons. As a consequence, we find that T
and T
are of limited value for predicting past, present and future distributions of species. This article is part of the theme issue 'Physiological diversity, biodiversity patterns and global climate change: testing key hypotheses involving temperature and oxygen'.
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