Local Knowledge Spillovers and Development: An Exploration of the Software Cluster in Uruguay

The paper contributes to the understanding of the nature of local knowledge spillovers and their importance for innovation in clusters in developing countries. Using detailed primary data about a cluster of software firms in Montevideo, Uruguay, the paper finds plenty of evidence of the existence of pure unintentional knowledge spillovers. In addition, it supports previous theoretical studies that have contended that there are also many knowledge flows that are to some degree produced purposively by local parties—these flows can be placed somewhere in between pure spillovers and pure market transactions. While the respondents themselves place most value on knowledge flows that are more or less purposively co-produced with customer transactions, a more objective statistical analysis shows that good product/service-innovation performance is associated with intensive use of flows with more pronounced spillover characteristics. The respondents possibly underrate the latter because of their invisibility and spontaneous nature. Heavy use of knowledge flows lying close to the market-transaction side of the spectrum is found to be associated with relatively advanced organizational capability, but not with product innovation. Overall, the findings point towards the relevance of cluster-based policies to promote innovation in a less developed country context. Various policy measures to stimulate the local circulation of knowledge are suggested.     

Size‐Dependent Cytotoxicity of Monodisperse Silica Nanoparticles in Human Endothelial Cells

The effect that monodisperse amorphous spherical silica particles of different sizes have on the viability of endothelial cells (EAHY926 cell line) is investigated. The results indicate that exposure to silica nanoparticles causes cytotoxic damage (as indicated by lactate dehydrogenase (LDH) release) and a decrease in cell survival (as determined by the tetrazolium reduction, MTT, assay) in the EAHY926 cell line in a dose‐related manner. Concentrations leading to a 50% reduction in cell viability (TC₅₀) for the smallest particles tested (14‐, 15‐, and 16‐nm diameter) ranging from 33 to 47 µg cm^?2 of cell culture differ significantly from values assessed for the bigger nanoparticles: 89 and 254 µg cm^?2 (diameter of 19 and 60 nm, respectively). Two fine silica particles with diameters of 104 and 335 nm show very low cytotoxic response compared to nanometer‐sized particles with TC₅₀ values of 1095 and 1087 µg cm^?2, respectively. The smaller particles also appear to affect the exposed cells faster with cell death (by necrosis) being observed within just a few hours. The surface area of the tested particles is an important parameter in determining the toxicity of monodisperse amorphous silica nanoparticles.     

Recent advances and future challenges in the use of nanoparticles for the dispersal of infectious biofilms

Increasing occurrence of intrinsically antimicrobial-resistant,human pathogens and the protective biofilm-mode in which they grow,dictates a need for the alternative control of infectious biofilms.Biofilm bacteria utilize dispersal mechanisms to detach parts of a biofilm as part of the biofilm life-cycle during times of nutrient scarcity or overpopulation.We here identify recent advances and future challenges in the development of dispersants as a new infection-control strategy.Deoxyribonuclease(DNase)and other extracellular enzymes can disrupt the extracellular matrix of a biofilm to cause dispersal.Also,a variety of small molecules,reactive oxygen species,nitric oxide releasing compounds,peptides and molecules regulating signaling pathways in biofilms have been described as dispersants.On their own,dispersants do not inhibit bacterial growth or kill bacterial pathogens.Both natural,as well as artificial dispersants,are unstable and hydrophobic which necessitate their encapsulation in smart nanocarriers,like pH-responsive micelles,liposomes or hydrogels.Depending on their composition,nanoparticles can also possess intrinsic dispersant properties.Bacteria dispersed from an infectious biofilm end up in the blood circulation where they are cleared by host immune cells.However,this sudden increase in bacte-rial concentration can also cause sepsis.Simultaneous antibiotic loading of nanoparticles with dispersant properties or combined administration of dispersants and antibiotics can counter this threat.Importantly,biofilm remaining after dispersant administration appears more susceptible to existing antibiotics.Being part of the natural biofilm life-cycle,no signs of"dispersant-resistance"have been observed.Dispersants are therewith promising for the control of infectious biofilms.     

The impact of including images in a conjoint measurement task: evidence from two small-scale studies

In the Netherlands, a large ongoing study seeks to provide insight into the process behind preferences and choices with regard to moving and housing. As part of the development of the survey instrument that was used in this study, we examined whether visual images (such as photographs) should be included, since they may clarify particular attributes (e.g., architectural style) and make the choice task more realistic for the respondents. However, images may disturb the results as respondents may evaluate accidental details on the photographs such as the color of the window frames. This paper presents the results of two subsequent pilot studies on the impact of including images in a web-based questionnaire. In the first study, eight dwelling profiles were presented in three different ways (“text only”, “text and color photo” and “text and black-and-white impression”) to 28 respondents. In the second study two different instruments were used: one with written information and directly shown photo-collages; the other with written information and photo-collages on request only. Both studies showed that the inclusion of images led to a number of differences between the results obtained with the various presentation methods. These differences may be explained by accidental details on the images. Furthermore, dwelling characteristics appear to be more important to the respondents’ overall evaluation of a dwelling when shown with photos than when presented in written format. However, since including images also has a substantial number of benefits, it may not be advisable to leave out images completely from the measurement task. Should images be included in a survey instrument, it is of utmost importance to make sure that all potentially disturbing details are cleared away. Furthermore, it may be better to show a collage of pictures than only one in order to decrease the specific impact of accidental details.     

Postmortem proteome degradation profiles of longissimus muscle in Yorkshire and Duroc pigs and their relationship with pork quality traits

Conversion of muscle to meat is regulated by complex interactions of biochemical processes that take place during postmortem storage of the carcass. Enzymatic proteolysis, among other postmortem biochemical phenomena; e.g. glycolysis; changes tough intact muscle tissue into more tender meat. Knowledge on proteome-wide proteolysis of muscle tissue in relation to meat quality is limited and potential breed-specific differences have received little attention. Therefore, we investigated meat quality traits and proteolysis profiles of the longissimus proteome of five Yorkshire and five Duroc pigs at slaughter and after 1, 2, 3, 7, and 10 days of ageing. Drip loss increased with ageing while cooking loss was unchanged in both breeds. Shear force varied between animals and decreased with ageing. Analysis of the proteomes showed four types of temporal expression profiles. Association analysis suggested several potential protein biomarkers for drip loss and shear force in both breeds, but none for cooking loss.     

Clearance of ESKAPE Pathogens from Blood Using Bacterially Activated Macrophage Membrane-Coated Silicon Nanowires

Extracorporeal devices to cleanse blood from infecting bacteria are based upon bacterial capture to surfaces, but the current generation of capture devices has variable and inconclusive therapeutic efficacy. Here, a microfluidic device equipped with a Si capture surface with a highly periodic nanowired structure is designed. Nanowired Si surfaces are coated with macrophage membranes to benefit from the natural blood compatibility and ligand–receptor binding of macrophages. When macrophages are activated by uptake of Staphylococcus aureus or Escherichia coli, zeta potentials of activated macrophage membrane coatings become less negative than those of nonactivated ones, stimulating nonspecific bacterial capture. In addition, Toll-like receptors in bacterially activated membrane coatings on nanowired surfaces that are absent in nonactivated membrane coatings contribute to specific bacterial capture. These two factors, together with the maintenance of fluidity in activated membrane coatings, cause broad spectrum, high capture efficiencies of all six ESKAPE member pathogens, considered most threatening to human health. Surfaces with such broad-spectrum capture efficiencies have not been previously described, but are clinically most relevant because blood cleansing should start as soon as possible after a septic patient becomes symptomatic, when the causative bacterial strain is still unknown.     

Self-centering probes with parallel kinematics to verify machine-tools

In this paper, a new type of self-centering probe is presented to verify the performance of machine-tools in an efficient and rapid way using ball artifacts. A self-centering probe is placed in the spindle of the machine-tool and a ball artifact on the work table. The probe is moved to the calibrated center positions of the balls of the reference artifact. The probe touches these balls and, in a single measurement, it provides the X, Y, Z offset of the actual machine position from the desired (programmed) position. A non-conventional probe design has been chosen: three independently movable probe styli form a miniature coordinate measuring machine with parallel kinematics. The development process of two variants of such a self-centering probe is presented in this paper. The results obtained in laboratory tests show a repeatability of less than 0.5 μm and an error range of less than 2 μm throughout the large measurement range (2 mm × 2 mm × 2 mm) of the probe.     

Perceived health and pregnancy: study of several behavioral and environmental determinants among a population of pregnant women

The nurturing of the adolescent patient's emerging sexuality can form the foundation for a lifelong ability to form intimate and trusting relationships. Teen pregnancy and sexually transmitted infections, the consequences of teen sexuality in crisis, impact the adolescent and our society. Psychosocial developmentally-appropriate counseling in the primary care physician's office must be part of each visit. A nonjudgmental, empathic approach is instrumental in the prevention of adolescent morbidity and mortality.     

Same-sex attraction, social relationships, psychosocial functioning, and school performance in early adolescence.

The authors examined whether 13- to 15-year-old adolescents who experience feelings of same-sex attraction (SSA) differ from those without such feelings in the quality of relationships with parents, peers, and class mentors and in psychosocial functioning (health status and school performance). The authors also assessed whether differences in psychosocial functioning resulted from differences in the quality of social relationships. Data were collected from 866 Dutch high school students (mean age 13.61 years) by means of a computer-based questionnaire. Of the participants, 74 (8.5%) reported having feelings of SSA. The participants with SSA rated the quality of their relationships with their fathers and their peers lower than did those without SSA. Participants with SSA also had poorer mental health (higher levels of depression and lower levels of self-esteem) and lower school performance. A mediation analysis revealed that differences in psychosocial functioning resulted from differences in the quality of the same-sex attracted youths' social relationships, especially with fathers and peers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)