University of St Andrews

About: University of St Andrews is a education organization based out in St Andrews, Fife, United Kingdom. It is known for research contribution in the topics: Population & Laser. The organization has 16260 authors who have published 43364 publications receiving 1636072 citations. The organization is also known as: St Andrews University & University of St. Andrews.

Self-employment Wealth and Job Creation: The Roles of Gender, Non-pecuniary Motivation and Entrepreneurial Ability

Abstract: This paper uses National Child Development Study data for a large cohort of British individuals, to explore the influence of education, inheritance and other background characteristics on the propensity to become self-employed; and also on subsequent success, as measured by job and wealth creation. For the first time, we study the effects of our regressor variables on our success measures via disaggregation of our sample by gender – and, in this way, reveal striking differences between the determinants of male and female entrepreneurial performance.

Transient fluvial incision in the headwaters of the Yellow River, northeastern Tibet, China

Abstract: [1] We utilize topographic analysis of channel profiles combined with field measurements of erosion rates to explore the distribution of channel incision in the Anyemaqen Shan, a broad mountainous region in the northeastern Tibetan plateau. Tributary channels to the Yellow River display systematic downstream increases in channel gradient associated with convex upward longitudinal profiles. Steep lower reaches of channels are associated with rapid (>1 m/ka) incision rates along the Yellow River, while upstream reaches are associated with relatively slow (0.05–0.1 m/ka) erosion of soil-mantled uplands. Covariance between erosion rates and channel steepness indices suggest that channels are adjusted to match long-wavelength differential rock uplift across the range. Geologic constraints indicate that rapid incision downstream of the range is associated with excavation of basin fill driven by changes in relative base level farther downstream. The upstream limit of this wave of transient incision is marked by a series of knickpoints that are found at nearly the same elevation throughout the watershed, consistent with knickpoint migration as a kinematic, rather than diffusional, wave. Tributary channel gradients downstream of knickpoints, however, display a progressive adjustment to increased incision rates that may reflect the influence of increased sediment flux. Comparison of observed channel profiles to a stream power model of fluvial behavior reveals that the rate of knickpoint propagation can only be explained if the erosional efficiency coefficient (K) increases during incision. Our results thus highlight the utility of channel profile analysis to reconstruct the fluvial response to both active tectonism and external changes in base level.

Why flower visitation is a poor proxy for pollination: measuring single-visit pollen deposition, with implications for pollination networks and conservation

Abstract: Summary The relative importance of specialized and generalized plant-pollinator relationships is contentious, yet analyses usually avoid direct measures of pollinator quality (effectiveness), citing difficulties in collecting such data in the field and so relying on visitation data alone. We demonstrate that single-visit deposition (SVD) of pollen on virgin stigmas is a practical measure of pollinator effectiveness, using 13 temperate and tropical plant species. For each flower the most effective pollinator measured from SVD was as predicted from its pollination syndrome based on traditional advertisement and reward traits. Overall, c.n40% of visitors were not effective pollinators (range 0n78% for different flowers); thus, flowernpollinator relationships are substantially more specialized than visitation alone can reveal. Analyses at species level are crucial, as significant variation in SVD occurred within both higher-level taxonomic groups (genus, family) and within functional groups. Other measures sometimes used to distinguish visitors from pollinators (visit duration, frequency, or feeding behaviour in flowers) did not prove to be suitable proxies. Distinguishing between lpollinatorsr and lvisitorsr is therefore crucial, and true lpollination networksr should include SVD to reveal pollinator effectiveness (PE). Generating such networks, now underway, could avoid potential misinterpretations of the conservation values of flower visitors, and of possible extinction threats as modelled in existing networks.

Modern radiation therapy for extranodal lymphomas: field and dose guidelines from the International Lymphoma Radiation Oncology Group.

Abstract: Extranodal lymphomas (ENLs) comprise about a third of all non-Hodgkin lymphomas (NHL). Radiation therapy (RT) is frequently used as either primary therapy (particularly for indolent ENL), consolidation after systemic therapy, salvage treatment, or palliation. The wide range of presentations of ENL, involving any organ in the body and the spectrum of histological sub-types, poses a challenge both for routine clinical care and for the conduct of prospective and retrospective studies. This has led to uncertainty and lack of consistency in RT approaches between centers and clinicians. Thus far there is a lack of guidelines for the use of RT in the management of ENL. This report presents an effort by the International Lymphoma Radiation Oncology Group (ILROG) to harmonize and standardize the principles of treatment of ENL, and to address the technical challenges of simulation, volume definition and treatment planning for the most frequently involved organs. Specifically, detailed recommendations for RT volumes are provided. We have applied the same modern principles of involved site radiation therapy as previously developed and published as guidelines for Hodgkin lymphoma and nodal NHL. We have adopted RT volume definitions based on the International Commission on Radiation Units and Measurements (ICRU), as has been widely adopted by the field of radiation oncology for solid tumors. Organ-specific recommendations take into account histological subtype, anatomy, the treatment intent, and other treatment modalities that may be have been used before RT.