236 research outputs found
Assessing the effectiveness of business support services in England: evidence from a theory based evaluation
In England, publicly supported advisory services for small firms are organised primarily through the Business Link (BL) network. Based on the programme theory underlying this business support services we develop four propositions and test these empirically using data from a new survey of over 3,000 English small firms. Our empirical results provide a broad validation of the programme theory underlying BL assistance for small firms in England during 2003, and more limited support for its effectiveness. More specifically, we find strong support for the value of BL operators maintaining a high profile as a way of boosting take-up. We also find some support for the approach to market segmentation adopted by BL allowing more intensive assistance to be targeted on younger firms and those with limited liability status. In terms of the outcomes of BL support, and allowing for issues of sample selection, we find no significant effects on growth from ‘other’ assistance but do find positive and significant employment growth effects from intensive assistance. This provides partial support for the programme theory assertion that BL support will lead to improvements in business growth performance and stronger support for the proposition that there would be differential outcomes from intensive and other assistance. The positive employment growth outcomes identified here from intensive assistance, even allowing for sample selection, suggest something of an improvement in the effectiveness of the BL network since the late 1990s
The while of participation: A systematic review of participatory research involving people with sensory impairments and/or intellectual impairments.
This paper reports on the first systematic review of literature associated with participatory research involving people identified with sensory impairments and/or intel- lectual impairments. It was initiated as part of ARCHES, an European Union-funded heritage project. The review sought to examine processes and activities used for organising participatory research involving people identified with sensory and/or intellectual impairments. 54 papers were included, involving studies from 14 countries and varying numbers of participants across different time scales. Insights were gained into use of advisory groups, organisation and support, collecting and analysing data, sharing findings and activity types. Emergent themes enabled an identification of the while of participation. The while represents the tensions, outcomes and component parts which are evident within the multiple moments that span an experience of participatory research. Participation is not about types of activity but how any activity is undertaken
Optimal static pricing for a tree network
We study the static pricing problem for a network service provider in a loss system with a tree structure. In the network, multiple classes share a common inbound link and then have dedicated outbound links. The motivation is from a company that sells phone cards and needs to price calls to different destinations. We characterize the optimal static prices in order to maximize the steady-state revenue. We report new structural findings as well as alternative proofs for some known results. We compare the optimal static prices versus prices that are asymptotically optimal, and through a set of illustrative numerical examples we show that in certain cases the loss in revenue can be significant. Finally, we show that static prices obtained using the reduced load approximation of the blocking probabilities can be easily obtained and have near-optimal performance, which makes them more attractive for applications.Massachusetts Institute of Technology. Center for Digital BusinessUnited States. Office of Naval Research (Contract N00014-95-1-0232)United States. Office of Naval Research (Contract N00014-01-1-0146)National Science Foundation (U.S.) (Contract DMI-9732795)National Science Foundation (U.S.) (Contract DMI-0085683)National Science Foundation (U.S.) (Contract DMI-0245352
Employment and SMEs during crises
The persistent increasing duration of unemployment has become an issue during economic crises. Although lay-offs at large firms normally make headlines during crises, we still know little about the potential impact of firm size on adjustment behavior in a crisis. We studied effects of firm size on employment growth during economic slowdowns using a rich microeconomic database for the 1988-2007 period in Portuguese manufacturing industry. The results show that economic downturns affect firm growth negatively. This negative effect is found to be higher for larger firms, both during and immediately following crisis periods. Small and medium-sized enterprises (SMEs) emerge as potential stabilizers in downturn periods. However, larger firms seem to be able to quickly recover from downturn periods. Our results contribute to the scarce literature and to the understanding of the Portuguese case, where many SMEs secure most jobs. These first results may be useful, because SMEs play a determinant role in other European Union economies
Expanding HIV Testing Efforts in Concentrated Epidemic Settings: A Population-Based Survey from Rural Vietnam
All in-text references underlined in blue are linked to publications on ResearchGate, letting you access and read them immediately
Binarized Support Vector Machines
The widely used support vector machine (SVM) method has shown to yield very good results in supervised classification problems. Other methods such as classification trees have become more popular among practitioners than SVM thanks to their interpretability, which is an important issue in data mining. In this work, we propose an SVM-based method that automatically detects the most important predictor variables and the role they play in the classifier. In particular, the proposed method is able to detect those values and intervals that are critical for the classification. The method involves the optimization of a linear programming problem in the spirit of the Lasso method with a large number of decision variables. The numerical experience reported shows that a rather direct use of the standard column generation strategy leads to a classification method that, in terms of classification ability, is competitive against the standard linear SVM and classification trees. Moreover, the proposed method is robust; i.e., it is stable in the presence of outliers and invariant to change of scale or measurement units of the predictor variables. When the complexity of the classifier is an important issue, a wrapper feature selection method is applied, yielding simpler but still competitive classifiers
Ligand Mobility Modulates Immunological Synapse Formation and T Cell Activation
T cell receptor (TCR) engagement induces clustering and recruitment to the plasma membrane of many signaling molecules, including the protein tyrosine kinase zeta-chain associated protein of 70 kDa (ZAP70) and the adaptor SH2 domain-containing leukocyte protein of 76 kDa (SLP76). This molecular rearrangement results in formation of the immunological synapse (IS), a dynamic protein array that modulates T cell activation. The current study investigates the effects of apparent long-range ligand mobility on T cell signaling activity and IS formation. We formed stimulatory lipid bilayers on glass surfaces from binary lipid mixtures with varied composition, and characterized these surfaces with respect to diffusion coefficient and fluid connectivity. Stimulatory ligands coupled to these surfaces with similar density and orientation showed differences in their ability to activate T cells. On less mobile membranes, central supramolecular activation cluster (cSMAC) formation was delayed and the overall accumulation of CD3ζ at the IS was reduced. Analysis of signaling microcluster (MC) dynamics showed that ZAP70 MCs exhibited faster track velocity and longer trajectories as a function of increased ligand mobility, whereas movement of SLP76 MCs was relatively insensitive to this parameter. Actin retrograde flow was observed on all surfaces, but cell spreading and subsequent cytoskeletal contraction were more pronounced on mobile membranes. Finally, increased tyrosine phosphorylation and persistent elevation of intracellular Ca2+ were observed in cells stimulated on fluid membranes. These results point to ligand mobility as an important parameter in modulating T cell responses
Diminution of Voltage Threshold Plays a Key Role in Determining Recruitment of Oculomotor Nucleus Motoneurons during Postnatal Development
The size principle dictates the orderly recruitment of motoneurons (Mns). This principle assumes that Mns of different sizes have a similar voltage threshold, cell size being the crucial property in determining neuronal recruitment. Thus, smaller neurons have higher membrane resistance and require a lower depolarizing current to reach spike threshold. However, the cell size contribution to recruitment in Mns during postnatal development remains unknown. To investigate this subject, rat oculomotor nucleus Mns were intracellularly labeled and their electrophysiological properties recorded in a brain slice preparation. Mns were divided into 2 age groups: neonatal (1–7 postnatal days, n = 14) and adult (20–30 postnatal days, n = 10). The increase in size of Mns led to a decrease in input resistance with a strong linear relationship in both age groups. A well-fitted inverse correlation was also found between input resistance and rheobase in both age groups. However, input resistance versus rheobase did not correlate when data from neonatal and adult Mns were combined in a single group. This lack of correlation is due to the fact that decrease in input resistance of developing Mns did not lead to an increase in rheobase. Indeed, a diminution in rheobase was found, and it was accompanied by an unexpected decrease in voltage threshold. Additionally, the decrease in rheobase co-varied with decrease in voltage threshold in developing Mns. These data support that the size principle governs the recruitment order in neonatal Mns and is maintained in adult Mns of the oculomotor nucleus; but during postnatal development the crucial property in determining recruitment order in these Mns was not the modifications of cell size-input resistance but of voltage threshold
- …