285 research outputs found
Entrepreneurship and social networks in IT sectors: the case of the software industry
DINĂ‚MIA, Dezembro de 2008Empirical research has repeatedly confirmed that social networks are important for the
creation, survival and growth of new companies. In this article, the leading research questions
are: 1) how do networks contribute to the creation of software firms and further development of
a competitive IT sector; 2) what is the structure and features of those networks; 3) how have
they evolved from the companies’ founding stage to the current period; 4) what resources
(scientific and technological knowledge, skills, and others) do entrepreneurs mobilize through
their networks. Based on a survey of 13 companies, those research questions have been tested,
using a methodology that combines applied statistical techniques and social network analysis.
Our results seem to support our research questions. They also show that some companies and
research units play a relevant role as brokers in the access of many companies to technological, informational and other resources.L’évidence empirique a montré à plusieurs reprises l’importance des réseaux personnels
des entrepreneurs pour la création et la réussite des entreprises. Dans cet article, les questions de recherche fondamentales sont: 1) quel est le rôle des réseaux sociaux dans la création des entreprises du secteur du logiciel pour les télécommunications; 2) quelles sont la structure et les
caractéristiques de ces réseaux; 3) quelle a été l’évolution de ces réseaux depuis leur création jusqu’à présent; 4) quelles sont les ressources (connaissances scientifique et technologique, qualifications, etc.) et les sources mobilisées par les entrepreneurs à travers les réseaux. Nous avons procédé au test de nos hypothèses sur un groupe de 13 entreprises du secteur, ayant
recours à une méthodologie qui combine les techniques statistiques et l’analyse des réseaux sociaux. Les résultats semblent confirmer nos questions de recherche. Par ailleurs, ils révèlent l’existence de quelques entreprises et organisations de recherche qui assurent un rôle d’intermédiaires, permettant l’accès à nombre d’entreprises aux ressources technologiques et informationnelles fondamentales.FC
Bacterial Meningitis in Newborn Babies
Objectivo — Conhecer a epidemiologia da meningite bacteriana em recém-nascidos admitidos na Unidade de Cuidados
Intensivos Neonatais do Hospital de Dona Estefânia.
Doentes e métodos — Foi feita a revisão dos processos de recém-nascidos admitidos na Unidade de Cuidados Intensivos
Neonatais do Hospital de Dona Estefânia de Janeiro de 1985 a Dezembro de 1996 — 12 anos, provenientes da maternidade do
Hospital ou do exterior. Foram excluĂdas as infecções congĂ©nitas e as crianças com idade superior a 28 dias. Definiu-se como
precoce a infecção com inĂcio nas primeiras 72 horas de vida.
Resultados — Houve 36 casos de meningite bacteriana correspondendo a 1,1% das admissões. A incidência de meningite
bacteriana precoce na Maternidade do Hospital foi 0,13 por mil nados-vivos. Vinte e quatro crianças eram do sexo masculino (66,7%), 7 eram pré-termo, 4 de baixo peso e 1 de muito baixo peso. Dez recém-nascidos tiveram meningite precoce (27,8%) e 26 (72,2%) meningite tardia. Houve isolamento do agente bacteriano
no lĂquido cefalorraquidiano em 27 crianças (77,1%): E. coli (n=7); Streptococcus do grupo B(SGB) (n=6); Klebsiella pneumoniae (n=3); Proteus mirabilis (n=2), Listeria monocytogenes
(n=1), Streptococcus bovis (n=1), Staphylococcus aureus (n=1), Neisseria meningitidis (n=2) e Salmonella tiphy (n=1). Houve ainda o isolamento de 3 Gram negativos nĂŁo identificados. A hemocultura foi positiva em 19 de 32 colheitas (59,4%). Na ausĂŞncia de terapĂŞutica antibiĂłtica, em 6 casos a cultura do
lĂquor foi positiva e a hemocultura negativa e noutros 2 ambas as culturas foram negativas. Durante o internamento faleceram 9 recĂ©m-nascidos — mortalidade de 25% e em 11 foram detectadas sequelas.
ConclusĂŁo — Houve um predomĂnio de casos de meningite tardia, em recĂ©m-nascidos de termo e do sexo masculino. Os agentes mais frequentemente encontrados foram a E. coli e a Streptococcus do grupo B
Melhor Suporte Nutricional — «Melhor» Composição Corporal? Uma Análise em Recém-Nascidos de Baixo Peso
Objectivo: Avaliar o impacto de diferentes estratégias de suporte nutricional na composição corporal de recém-nascidos de baixo peso (RNBP), por intermédio não só do peso, mas também das áreas muscular braquial (AMB) e adiposa braquial (AAB).
IndivĂduos e mĂ©todos: Comparou-se a mĂ©dia do dia de recuperação do peso, da AMB e da AAB entre dois grupos de RNBP assistidos em perĂodos distintos, com suportes nutricionais diferentes — grupo I (n=10): 1991 versus grupo II (n=24): 1995/96. Os
recém-nascidos foram incluidos de modo consecutivo e avaliados prospectivamente sob o ponto de vista antropométrico.
Resultados: NĂŁo houve diferenças significativas da mĂ©dia das idades gestacionais e dos pesos de nascimento entre os dois grupos. Os recĂ©m-nascidos do grupo II, comparativamente com os do grupo I, receberam provisões mais precoces de energia, lĂpidos e proteĂnas atravĂ©s da alimentação parentĂ©rica. NĂŁo se observaram diferenças significativas no dia de recuperação do peso e da AMB entre
os grupos. No entanto, os RN do grupo II recuperaram mais precocemente a AAB (dia 6,9 ± 2,5 vs dia 12,6 ± 5,1) (p<0,01), apĂłs um perĂodo inicial de declĂnio dos respectivos valores.
Conclusões: O atraso na adequada provisĂŁo de energia e proteĂnas pode ter um impacto negativo na reserva lipĂdica, nĂŁo detectada pela observação isolada da evolução ponderai. A medição das áreas braquiais representa um mĂ©todo simples e nĂŁo invasivo de avaliação indirecta da composição corporal dos RNBP
Repercussão das Colheitas de Sangue sobre os Valores de Hemoglobina em Recém-Nascidos de Muito Baixo Peso (RNMBP) Submetidos a Terapia Intensiva
A perda iatrogĂ©nica de sangue constitui um problema comum nas unidades de cuidados intensivos neonatais. O objectivo deste trabalho foi quantificaras espoliações de sangue para estudos analĂticos em 22 RNMBP durante as primeiras trĂŞs semanas de hospitalização. O nĂşmero mĂ©dio de colheitas por criança e por dia foi IA e o nĂşmero mĂ©dio de colheitas por criança no perĂodo estudado foi 29.7. O valor cumulativo mĂ©dio de sangue espoliado pelo 21." dia foi 18,7 ml/kg. Os valores mĂ©dios de hemoglobina nas primeiras 12 horas de tida e no 21." dia foram respectivamente 16.4 e 12.9 gr/d1. Verificou-se
uma relação estreita entre o volume de sangue extraĂdo e o volume de sangue transfundido. sugerindo este facto que. em geral. as transfusões sĂŁo efectuadas
por necessidade de compensar as perdas sanguĂneas relacionadas com as colheitas de sangue.
Conclui-se que as espoliações repetidas de sangue para análises laboratoriais se repercutem significativamente nos valores de hemoglobina dos recém-nascidos
pretermo e de MBP sendo portanto desejável que tais espoliações sejam rigorosamente quantificadas e reduzidas ao mĂnimo tendo em conta os riscos das transfusões de sangue
Changes in the biophysical properties of the cell membrane are involved in the response of neurospora crassa to staurosporine
Neurospora crassa is a non-pathogenic filamentous fungus widely used as a multicellular eukaryotic model. Recently, the biophysical properties of the plasma membrane of N. crassa conidia were thoroughly characterized. They evolve during conidial germination at a speed that depends on culture conditions, suggesting an important association between membrane remodeling and the intense membrane biogenesis that takes place during the germinative process. Staurosporine (STS) is a drug used to induce programmed cell death in various organisms. In N. crassa, STS up-regulates the expression of the ABC transporter ABC-3, which localizes at the plasma membrane and pumps STS out. To understand the role of plasma membrane biophysical properties in the fungal drug response, N. crassa was subjected to STS treatment during early and late conidial development stages. Following 1 h treatment with STS, there is an increase in the abundance of the more ordered, sphingolipid-enriched, domains in the plasmamembrane of conidia. This leads to higher fluidity in othermembrane regions. The global order of the membrane remains thus practically unchanged. Significant changes in sphingolipid-enriched domains were also observed after 15min challenge with STS, but they were essentially opposite to those verified for the 1 h treatment, suggesting different types of drug responses. STS effects on membrane properties that are more dependent on ergosterol levels also depend on the developmental stage. There were no alterations on 2 h-grown cells, clearly contrasting to what happens at longer growth times. In this case, the differences were more marked for longer STS treatment, and rationalized considering that the drug prevents the increase in the ergosterol/glycerophospholipid ratio that normally takes place at the late conidial stage/transition to the mycelial stage. This could be perceived as a drug-induced development arrest after 5 h growth, involving ergosterol, and pointing to a role of lipid rafts possibly related with an up-regulated expression of the ABC-3 transporter. Overall, our results suggest the involvement of
membrane ordered domains in the response mechanisms to STS in N. crassa.
Neurospora crassa is a non-pathogenic filamentous fungus widely used as a multicellular eukaryotic model. Recently, the biophysical properties of the plasma membrane of N. crassa conidia were thoroughly characterized. They evolve during conidial germination at a speed that depends on culture conditions, suggesting an important association between membrane remodeling and the intense membrane biogenesis that takes place during the germinative process. Staurosporine (STS) is a drug used to induce programmed cell death in various organisms. In N. crassa, STS up-regulates the expression of the ABC transporter ABC-3, which localizes at the plasma membrane and pumps STS out. To understand the role of plasma membrane biophysical properties in the fungal drug response, N. crassa was subjected to STS treatment during early and late conidial development stages. Following 1 h treatment with STS, there is an increase in the abundance of the more ordered, sphingolipid-enriched, domains in the plasmamembrane of conidia. This leads to higher fluidity in othermembrane regions. The global order of the membrane remains thus practically unchanged. Significant changes in sphingolipid-enriched domains were also observed after 15min challenge with STS, but they were essentially opposite to those verified for the 1 h treatment, suggesting different types of drug responses. STS effects on membrane properties that are more dependent on ergosterol levels also depend on the developmental stage. There were no alterations on 2 h-grown cells, clearly contrasting to what happens at longer growth times. In this case, the differences were more marked for longer STS treatment, and rationalized considering that the drug prevents the increase in the ergosterol/glycerophospholipid ratio that normally takes place at the late conidial stage/transition to the mycelial stage. This could be perceived as a drug-induced development arrest after 5 h growth, involving ergosterol, and pointing to a role of lipid rafts possibly related with an up-regulated expression of the ABC-3 transporter. Overall, our results suggest the involvement of membrane ordered domains in the response mechanisms to STS in N. crassa.Fundação para a Ciência e a Tecnologia (FCT), Portugal, is acknowledged for grants PTDC/BBB-BQB/6071/2014, UID/Multi/00612/2013, IF/00317/2012, and PT2020 referring to research unit 4293. FS acknowledges Ph.D. scholarship SFRH/BD/108031/2015, also from FCT
Upper Arm Anthropometry Is Not a Valid Predictor of Regional Body Composition in Preterm Infants
Background: Upper arm anthropometry has been used in the nutritional assessment of small infants, but it has not yet been validated as a predictor of regional body composition
in this population. Objective: Validation of measured and derived upper arm anthropometry as a predictor of arm fat and fat-free compartments in preterm infants. Methods: Upper arm anthropometry, including the upper arm cross-sectional areas, was compared individually or in combination with other
anthropometric measurements, with the cross-sectional arm areas measured by magnetic resonance imaging, in a cohort of consecutive preterm appropriate-for-gestationalage neonates, just before discharge. Results: Thirty infants
born with (mean 8 SD) a gestational age of 30.7 8 1.9 weeks and birth weight of 1,380 8 325 g, were assessed at 35.4 8 1.1 weeks of corrected gestational age, weighing 1,785 8
93 g. None of the anthropometric measurements are reliable predictors (r 2 ! 0.56) of the measurements obtained by magnetic resonance imaging, individually or in combination with other anthropometric measurements. Conclusion: Both
measured anthropometry and derived upper arm anthropometry are inaccurate predictors of regional body composition in preterm appropriate-for-gestational-age infants
Clinical Evidence of Vascular Abnormalities at Birth in Adams-Oliver Syndrome: Report of Two Further Cases
Bacterial activity in heavy metals polluted soils: Metal efflux systems in native rhizobial strains
The negative effect of high levels of heavy metals on the activity
of soil microorganisms is well-known. However, some microorganisms
survive even in high levels of heavy metals, and the microbial
activity can therefore, help to recover these polluted soils.
Microbial metal uptake in contaminated soils has to be tightly
regulated to avoid toxic effects for the cells. These mechanisms
of metal resistance are frequently associated to transport-related
membrane proteins that mediate bacterium’s direct metabolic interactions
with the complex soil and aquatic harsh environments.
This study reports the identification of gene clusters in rhizobial
strains that are regulated by heavy metals, particularly chromium.
A DNA fragment was amplified from R. leguminosarum, and
in silico analysis of the sequence obtained revealed a putative
protein homologue to a cation/multidrug efflux pump component
(GenBank DQ398937). Another amplified DNA fragment,
with 960 bp, has strong homology with anion ABC transporters
(GenBank ZP 002212691) and a peptide ABC transporter (Gen-
Bank NP 766950), was identified in Mesorhizobium loti (GenBank
DQ398941) and Sinorhizobium meliloti. Using ChromosomeWalking
technique, a single product from Sinorhizobium meliloti was
cloned and sequenced. This new fragment enlarged more 302 bp
to the initial sequence corresponding to the ABC transporter, confirming
homology with an ATPase from PP superfamily (GenBank
ZP 00197146.1)
Assessment of genetic biodiversity of indigenous Rhizobium species using ERIC-PCR and REP-PCR techniques
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