Correlating densities of centrality and activities in cities : the cases of Bologna (IT) and Barcelona (ES)

This paper examines the relationship between street centrality and densities of commercial and service activities in cities. The aim is to verify whether a correlation exists and whether some 'secondary' activities, i.e. those scarcely specialized oriented to the general public and ordinary daily life, are more linked to street centrality than others. The metropolitan area of Barcelona (Spain) is investigated, and results are compared with those found in a previous work on the city of Bologna (Italy). Street centrality is calibrated in a multiple centrality assessment (MCA) model composed of multiple measures such as closeness, betweenness and straightness. Kernel density estimation (KDE) is used to transform data sets of centrality and activities to one scale unit for correlation analysis between them. Results indicate that retail and service activities in both Bologna and Barcelona tend to concentrate in areas with better centralities, and that secondary activities exhibit a higher correlation

Epidemics in partially overlapped multiplex networks

Many real networks exhibit a layered structure in which links in each layer reflect the function of nodes on different environments. These multiple types of links are usually represented by a multiplex network in which each layer has a different topology. In real-world networks, however, not all nodes are present on every layer. To generate a more realistic scenario, we use a generalized multiplex network and assume that only a fraction $q$ of the nodes are shared by the layers. We develop a theoretical framework for a branching process to describe the spread of an epidemic on these partially overlapped multiplex networks. This allows us to obtain the fraction of infected individuals as a function of the effective probability that the disease will be transmitted $T$. We also theoretically determine the dependence of the epidemic threshold on the fraction $q > 0$ of shared nodes in a system composed of two layers. We find that in the limit of $q \to 0$ the threshold is dominated by the layer with the smaller isolated threshold. Although a system of two completely isolated networks is nearly indistinguishable from a system of two networks that share just a few nodes, we find that the presence of these few shared nodes causes the epidemic threshold of the isolated network with the lower propagating capacity to change discontinuously and to acquire the threshold of the other network.Comment: 13 pages, 4 figure

Half versus full vacuum suction drainage after modified radical mastectomy for breast cancer- a prospective randomized clinical trial[ISRCTN24484328]

BACKGROUND: Suction drains are routinely used after modified radical mastectomy and are an important factor contributing to increased hospital stay as the patients are often discharged only after their removal. Amongst various factors that influence the amount of postoperative drainage, the negative suction pressure applied to the drain has been reported to be of great significance. While a high negative suction pressure is expected to drain the collection and reduce the dead space promptly, it may also prevent the leaking lymphatics from closing and lead to increased drainage from the wound. Against this background a prospective randomized clinical study was conducted to compare the amount and duration of drainage between a half negative suction and full vacuum suction drainage in patients following modified radical mastectomy. The associated postoperative morbidity was also compared between the two groups. METHODS: 85 FNAC (fine needle aspiration cytology) proven cases of locally advanced breast cancer were randomized. (Using randomly ordered sealed envelops, which were opened immediately before the closure of the wound) in to 50 patients with full vacuum suction (pressure = 700 g/m2) and 35 cases in to half vacuum suction drainage (pressure = 350 g/m2) groups. The two groups were comparable in respect of age, weight, and technique of operation and extent of axillary dissection. Surgery was performed by the same surgical team comprising of five surgeons (two senior and three resident surgeons) using a standardized technique with electrocautery. External compression dressing was provided over the axilla for first 48 hrs and following that patients were encouraged to do active and passive shoulder exercises. The outcomes measured were postoperative morbidity and the length of hospital stay. Statistical methods used: Descriptive studies were performed with SPSS version 10 and group characteristics were compared using student t-test. RESULTS: Half vacuum suction drains were removed earlier than the full suction vacuum suction drains. There was no significant difference in the incidence of seroma formation in the two groups and there was a significant reduction in the total hospital stay in patients with half vacuum suction drainage systems as compared to the full suction drainage group (p < 0.001) without any added morbidity. CONCLUSIONS: Half negative suction drains provide an effective compromise between no suction and full or high suction drainage after modified radical mastectomy by reducing the hospital stay and the post operative morbidity including post operative seromas

La importancia de las variables morfológicas, métricas y de microdesgaste para evaluar las diferencias en diseños de puntas de proyectil bifaciales pedunculadas: Un ejemplo del sur de Patagonia continental

The purpose of this paper is to evaluate the existence of variations in the design of stemmed bifacial projectile points recovered between the Santa Cruz basin and the Magellan Strait. Morphometric, metric and microwear analisys were applied on the stem of the proyectil points. While there are similar forms in the whole area, there are metrical and microwear differences between the samples coming for the north and south of the Santa Cruz basin. The causes of these results are evaluated in relation to environmental characteristics -lithic, prey and vegetation availability- and the possibility of the existente of different human populations.En este trabajo nos proponemos evaluar la existencia de variaciones en el diseño de puntas de proyectil bifaciales pedunculadas entre la cuenca del río Santa Cruz y el estrecho de Magallanes. Con este objetivo se aplicaron análisis morfométricos, métricos y de microdesgaste en los pedúnculos de estos instrumentos. Los mismos señalaron, por un lado, la existencia de semejanzas en su forma y por el otro, variaciones métricas y en el microdesgaste entre los conjuntos procedentes del norte y el sur del río Santa Cruz. Se discute si las causas de estas variaciones pueden relacionarse con características ambientales -como la disponibilidad de recursos líticos, faunísticos y vegetales- o con la existencia de diferentes poblaciones humanas.Facultad de Ciencias Naturales y Muse

La importancia de las variables morfológicas, métricas y de microdesgaste para evaluar las diferencias en diseños de puntas de proyectil bifaciales pedunculadas: Un ejemplo del sur de Patagonia continental

The purpose of this paper is to evaluate the existence of variations in the design of stemmed bifacial projectile points recovered between the Santa Cruz basin and the Magellan Strait. Morphometric, metric and microwear analisys were applied on the stem of the proyectil points. While there are similar forms in the whole area, there are metrical and microwear differences between the samples coming for the north and south of the Santa Cruz basin. The causes of these results are evaluated in relation to environmental characteristics -lithic, prey and vegetation availability- and the possibility of the existente of different human populations.En este trabajo nos proponemos evaluar la existencia de variaciones en el diseño de puntas de proyectil bifaciales pedunculadas entre la cuenca del río Santa Cruz y el estrecho de Magallanes. Con este objetivo se aplicaron análisis morfométricos, métricos y de microdesgaste en los pedúnculos de estos instrumentos. Los mismos señalaron, por un lado, la existencia de semejanzas en su forma y por el otro, variaciones métricas y en el microdesgaste entre los conjuntos procedentes del norte y el sur del río Santa Cruz. Se discute si las causas de estas variaciones pueden relacionarse con características ambientales -como la disponibilidad de recursos líticos, faunísticos y vegetales- o con la existencia de diferentes poblaciones humanas.Facultad de Ciencias Naturales y Muse