134 research outputs found
Psychological training for entrepreneurs to take action
Entrepreneurship is one of the most effective means to alleviate poverty in developing countries. Effective entrepreneurship requires psychological approaches—in particular, active (i.e., agentic) approaches. We introduce an action-regulation training approach, focusing on self-regulation and active behavior in entrepreneurship as a bottom-up solution for poverty reduction. We present two different training interventions. The first focuses on enhancing personal initiative in entrepreneurs from developing countries. The second aims at boosting startup rates in these countries by enhancing participants’ entrepreneurial skills and motivation. We describe underlying theoretical assumptions, structures, and effects of both training interventions and discuss evaluation studies with randomized pretest-posttest control-group designs showing that action-regulation training is a successful means to promote entrepreneurship in developing countries
Role of Physical Therapists in the Management of Individuals at Risk for or Diagnosed With Venous Thromboembolism: Evidence-Based Clinical Practice Guideline
The American Physical Therapy Association (APTA), in conjunction with the Cardiovascular & Pulmonary and Acute Care sections of APTA, have developed this clinical practice guideline to assist physical therapists in their decision-making process when treating patients at risk for venous thromboembolism (VTE) or diagnosed with a lower extremity deep vein thrombosis (LE DVT). No matter the practice setting, physical therapists work with patients who are at risk for or have a history of VTE. This document will guide physical therapist practice in the prevention of, screening for, and treatment of patients at risk for or diagnosed with LE DVT. Through a systematic review of published studies and a structured appraisal process, key action statements were written to guide the physical therapist. The evidence supporting each action was rated, and the strength of statement was determined. Clinical practice algorithms, based on the key action statements, were developed that can assist with clinical decision making. Physical therapists, along with other members of the health care team, should work to implement these key action statements to decrease the incidence of VTE, improve the diagnosis and acute management of LE DVT, and reduce the long-term complications of LE DVT
Strategies, Uncertainty and Performance of Small Business Startups
Personal strategies of owners/founders of small business startups are related to performance and to environmental uncertainty. This is done using a longitudinal data set of some 50 Dutch startups. The results suggest a dynamic process between strategy and performance.
A discrimination is made between four strategies (reactive, critical point, complete planning and opportunistic). The role of uncertainty is discussed. The dynamic process is embedded in the PERSUADE model
Polychromatic solar energy conversion in pigment-protein chimeras that unite the two kingdoms of (bacterio)chlorophyll-based photosynthesis
Natural photosynthesis can be divided between the chlorophyll-containing plants, algae and cyanobacteria that make up the oxygenic phototrophs and a diversity of bacteriochlorophyll-containing bacteria that make up the anoxygenic phototrophs. Photosynthetic light harvesting and reaction centre proteins from both kingdoms have been exploited for solar energy conversion, solar fuel synthesis and sensing technologies, but the energy harvesting abilities of these devices are limited by each protein’s individual palette of pigments. In this work we demonstrate a range of genetically-encoded, self-assembling photosystems in which recombinant plant light harvesting complexes are covalently locked with reaction centres from a purple photosynthetic bacterium, producing macromolecular chimeras that display mechanisms of polychromatic solar energy harvesting and conversion. Our findings illustrate the power of a synthetic biology approach in which bottom-up construction of photosystems using naturally diverse but mechanistically complementary components can be achieved in a predictable fashion through the encoding of adaptable, plug-and-play covalent interfaces
Sustaining Electron Transfer Pathways Extends Biohybrid Photoelectrode Stability to Years
The exploitation of natural photosynthetic enzymes in semi-artificial devices constitutes an attractive and potentially sustainable route for the conversion of solar energy into electricity and solar fuels. However, the stability of photosynthetic proteins after incorporation in a biohybrid architecture typically limits the operational lifetime of biophotoelectrodes to a few hours. Here, we demonstrate ways to greatly enhance the stability of a mesoporous electrode coated with the RC-LH1 photoprotein from Rhodobacter sphaeroides. By preserving electron transfer pathways, we extended operation under continuous high-light to 33 days, and operation after storage to over two years. Coupled with large photocurrents that reached peak values of 4.6 mA cm−2, the optimized biophotoelectrode produced a cumulative output of 86 C cm−2, the largest reported performance to date. Our results demonstrate that the factor limiting stability is the architecture surrounding the photoprotein, and that biohybrid sensors and photovoltaic devices with operational lifetimes of years are feasible
Demonstration of asymmetric electron conduction in pseudosymmetrical photosynthetic reaction centre proteins in an electrical circuit
Photosynthetic reaction centres show promise for biomolecular electronics as nanoscale solar-powered batteries and molecular diodes that are amenable to atomic-level re-engineering. In this work the mechanism of electron conduction across the highly tractable Rhodobacter sphaeroides reaction centre is characterized by conductive atomic force micro-scopy. We find, using engineered proteins of known structure, that only one of the two cofactor wires connecting the positive and negative termini of this reaction centre is capable of conducting unidirectional current under a suitably oriented bias, irrespective of the magnitude of the bias or the applied force at the tunnelling junction. This behaviour, strong functional asymmetry in a largely symmetrical protein–cofactor matrix, recapitulates the strong functional asymmetry characteristic of natural photochemical charge separation, but it is surprising given that the stimulus for electron flow is simply an externally applied bias. Reasons for the electrical resistance displayed by the so-called B-wire of cofactors are explored
What is Method Variance and How Can We Cope With It? A Panel Discussion
A panel of experts describes the nature of, and remedies for, method variance. In an attempt to help the reader understand the nature of method variance, the authors describe their experiences with method variance both on the giving and the receiving ends of the editorial review process, as well as their interpretation of other reviewers’ comments. They then describe methods of data analysis and research design, which have been used for detecting and eliminating the effects of method variance. Most methods have some utility, but none prevent the researcher from making faulty inferences. The authors conclude with suggestions for resolving disputes about method variance
A novel method for quantification of gemcitabine and its metabolites 2',2'-difluorodeoxyuridine and gemcitabine triphosphate in tumour tissue by LC-MS/MS: comparison with (19)F NMR spectroscopy.
PURPOSE: To develop a sensitive analytical method to quantify gemcitabine (2',2'-difluorodeoxycytidine, dFdC) and its metabolites 2',2'-difluorodeoxyuridine (dFdU) and 2',2'-difluorodeoxycytidine-5'-triphosphate (dFdCTP) simultaneously from tumour tissue. METHODS: Pancreatic ductal adenocarcinoma tumour tissue from genetically engineered mouse models of pancreatic cancer (KP ( FL/FL ) C and KP ( R172H/+) C) was collected after dosing the mice with gemcitabine. (19)F NMR spectroscopy and LC-MS/MS protocols were optimised to detect gemcitabine and its metabolites in homogenates of the tumour tissue. RESULTS: A (19)F NMR protocol was developed, which was capable of distinguishing the three analytes in tumour homogenates. However, it required at least 100Â mg of the tissue in question and a long acquisition time per sample, making it impractical for use in large PK/PD studies or clinical trials. The LC-MS/MS protocol was developed using porous graphitic carbon to separate the analytes, enabling simultaneous detection of all three analytes from as little as 10Â mg of tissue, with a sensitivity for dFdCTP of 0.2Â ng/mg tissue. Multiple pieces of tissue from single tumours were analysed, showing little intra-tumour variation in the concentrations of dFdC or dFdU (both intra- and extra-cellular). Intra-tumoural variation was observed in the concentration of dFdCTP, an intra-cellular metabolite, which may reflect regions of different cellularity within a tumour. CONCLUSION: We have developed a sensitive LC-MS/MS method capable of quantifying gemcitabine, dFdU and dFdCTP in pancreatic tumour tissue. The requirement for only 10Â mg of tissue enables this protocol to be used to analyse multiple areas from a single tumour and to spare tissue for additional pharmacodynamic assays
A Lagerstätte from Australia provides insight into the nature of Miocene mesic ecosystems
Reduced precipitation in the Miocene triggered the geographic contraction of rainforest ecosystems around the world. In Australia, this change was particularly pronounced; mesic rainforest ecosystems that once dominated the landscape transformed into the shrublands, grasslands, and deserts of today. A lack of well-preserved fossils has made it difficult to understand the nature of Australian ecosystems before the aridification. Here, we report on an exceptionally well-preserved rainforest biota from New South Wales, Australia. This Konservat-Lagerstätte hosts a rich diversity of microfossils, plants, insects, spiders, and vertebrate remains preserved in goethite. We document evidence for several species interactions including predation, parasitism, and pollination. The fossils are indicative of an oxbow lake in a mesic rainforest and suggest that rainforest distributions have shifted since the Miocene. The variety of fossils preserved, together with high fidelity of preservation, allows for unprecedented insights into the mesic ecosystems that dominated Australia during the Miocene
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MHD Modeling of Conductors at Ultra-High Current Density
In conjunction with ongoing high-current experiments on Sandia National Laboratories' Z accelerator, the authors have revisited a problem first described in detail by Heinz Knoepfel. Unlike the 1-Tesla MITLs of pulsed power accelerators used to produce intense particle beams, Z's disc transmission line (downstream of the current addition) is in a 100--1,200 Tesla regime, so its conductors cannot be modeled simply as static infinite conductivity boundaries. Using the MHD code MACH2 they have been investigating the conductor hydrodynamics, characterizing the joule heating, magnetic field diffusion, and material deformation, pressure, and velocity over a range of current densities, current rise-times, and conductor materials. Three purposes of this work are (1) to quantify power flow losses owing to ultra-high magnetic fields, (2) to model the response of VISAR diagnostic samples in various configurations on Z, and (3) to incorporate the most appropriate equation of state and conductivity models into the MHD computations. Certain features are strongly dependent on the details of the conductivity model
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