How does a bicycle work? A new instrument to assess mechanical reasoning in school aged children

This study demonstrated that a brief interview can reveal the mechanical reasoning that could not be assessed via the Bicycle Drawing Test. This study, conducted on 190 children (6 to 11 years old), shows that mechanical reasoning improves with age. It shows correlations with spatial reasoning and motor control, and with visual reasonin

First data on batch fecundity and relative fecundity of Sardina pilchardus (Walbaum, 1792) (Clupeidae) in the south-western Adriatic Sea

Se ha determinado por primera vez la fecundidad parcial y relativa de Sardina pilchardus (Walbaum, 1792) en las aguas del bajo Adriático con el método de los ovocitos hidratados. Las muestras han sido recogidas de la propia flota comercial y de embarcaciones alquiladas y equipadas con red de arrastre pelágico a la pareja, red de arrastre semipelágico a la pareja o red de cerco con jareta durante el periodo de reproducción. Se han estudiado diferentes modelos de regresión entre la fecundidad parcial y el peso de las hembras sin ovarios. El mejor ajuste corresponde a una regresión lineal. Se ha calculado también la fecundidad relativa (número de ovocitos por gramo de hembra sin ovarios) y se ha confrontado con la de otros clupeiformes.The batch fecundity and relative fecundity of Sardina pilchardus (Walbaum, 1792) have been determined for the first time in the waters of the Lower Adriatic Sea using the hydrated oocyte method. The samples were collected from the commercial fleet and chartered boats equipped with midwater pair trawls, midwater otter trawls and purse seine during the reproductive period. Various regression models were studied, to express the relationship between the batch fecundity and the weight of ovary-free females. The linear model proved to be the best one, because of its simplicity. Relative batch fecundity (number of hydrated oocytes per gram from ovary-free females) was also studied, and compared with that of other clupeiforms.Instituto Español de Oceanografí

Autologous fat grafting after sarcoma surgery : evaluation of oncological safety

Background: The regenerative effectiveness of lipoaspirate procedures relies on the presence of mesenchymal stem cells, but the stromal microenvironment and hormonal secretions of the adipose tissue may be involved in cancer growth. Only few oncological outcome studies of fat grafting at the surgical site of malignant neoplasms of mesenchymal origin are available; none of these studies examined a series of sarcoma cases. Objectives: We analyzed outcome in terms of local or distant spread and overall survival to investigate the oncological safety of fat grafting in patients with sarcoma. Patients and methods: Sixty consecutive patients who had undergone 143 fat grafting procedures after surgical resection of bone and soft tissue sarcomas of the head, trunk, and limbs with clear resection margins were enrolled from 2004 to 2015 in our tertiary care center. A multidisciplinary sarcoma team administered adjuvant therapies. Patients were recurrence free at fat grafting. Results: The overall median follow-up was 7.5 years. At follow-up after fat grafting (2.4 years), one patient had distant metastasis and two had local relapse. Kaplan\u2013Meier analysis showed disease-free survival rate of 95.4% (CI: 89.1\u2013100.0) at 24 months. The risk of local recurrence (LR) within 24 months was 4.6% (CI: 0.0\u201320.9). The probability of not having LR after fat grafting was 65 89.1%. Conclusion: We found no evidence of an increased cancer risk after fat grafting procedures in patients with sarcoma, but a stimulatory role of fat cannot be excluded for bone sarcomas based on the cases reported here, and further studies are therefore needed

Autologous fat grafting after sarcoma surgery : evaluation of oncological safety

Background: The regenerative effectiveness of lipoaspirate procedures relies on the presence of mesenchymal stem cells, but the stromal microenvironment and hormonal secretions of the adipose tissue may be involved in cancer growth. Only few oncological outcome studies of fat grafting at the surgical site of malignant neoplasms of mesenchymal origin are available; none of these studies examined a series of sarcoma cases. Objectives: We analyzed outcome in terms of local or distant spread and overall survival to investigate the oncological safety of fat grafting in patients with sarcoma. Patients and methods: Sixty consecutive patients who had undergone 143 fat grafting procedures after surgical resection of bone and soft tissue sarcomas of the head, trunk, and limbs with clear resection margins were enrolled from 2004 to 2015 in our tertiary care center. A multidisciplinary sarcoma team administered adjuvant therapies. Patients were recurrence free at fat grafting. Results: The overall median follow-up was 7.5 years. At follow-up after fat grafting (2.4 years), one patient had distant metastasis and two had local relapse. Kaplan–Meier analysis showed disease-free survival rate of 95.4% (CI: 89.1–100.0) at 24 months. The risk of local recurrence (LR) within 24 months was 4.6% (CI: 0.0–20.9). The probability of not having LR after fat grafting was ≥ 89.1%. Conclusion: We found no evidence of an increased cancer risk after fat grafting procedures in patients with sarcoma, but a stimulatory role of fat cannot be excluded for bone sarcomas based on the cases reported here, and further studies are therefore needed

Local safety of immediate reconstruction during primary treatment of breast cancer : direct-to-implant versus expander-based surgery

Introduction: After mastectomy, immediate breast reconstruction is paramount. With the growing number of nipple-sparing mastectomies, the chances of successful one-stage reconstruction with implants are also increasing. Local safety is one of the main issues. This study investigated the factors that could lead to major or minor complications after expander-based versus direct-to-implant (DTI) reconstruction. Methods: The studied factors were age, body mass index (BMI), hypertension, smoking, diabetes, type of mastectomy (nipple-sparing/total), implant size, neoadjuvant/adjuvant chemotherapy, and radiotherapy. The study sample included 294 immediate reconstructions over 3 years. The primary outcome was the incidence of complications, major or minor depending on the necessity of revision surgery. For the DTI pocket, we applied a variant of the conventional submuscular technique. Results: In DTI reconstructions (median follow-up 26 months), the complication rate was 17.2% (4.3% major and 12.8% minor) with no significant association with clinical variables. In expander-based reconstructions (median follow-up 19 months), the complication rate was 18.3% (12.5% major and 5.8% minor). Univariate analysis showed a significant association between overall complications and radiotherapy (P = 0.01) as well as between major complications and expander size (P < 0.005), BMI (P < 0.005), and radiotherapy (P < 0.01); radiotherapy and BMI retained significance in multivariate analysis. Neoadjuvant/adjuvant chemotherapy did not affect the complication rate. Conclusions: There was evidence of an association between major complications and clinical variables in the expander-based cohort. Larger expander size was a predictor of failure, especially combined with radiation. Direct-to-implant reconstruction proved to be safe. We describe a reliable method of reconstruction and a safe range of implant sizes even beyond 500 g

Shell-supported footbridges

Architects and engineers have been always attracted by concrete shell structures due to their high efficiency and plastic shapes. In this paper the possibility to use concrete shells to support footbridges is explored. Starting from Musmeci's fundamental research andwork in shell bridge design, the use of numerical formfinding methods is analysed. The form-finding of a shellsupported footbridge shaped following Musmeci's work is first introduced. Coupling Musmeci's and Nervi's experiences, an easy construction method using a stay-inplace ferrocement formwork is proposed. Moreover, the advantage of inserting holes in the shell through topology optimization to remove less exploited concrete has been considered. Curved shell-supported footbridges have been also studied, and the possibility of supporting the deck with the shell top edge, that is along a single curve only, has been investigated. The form-finding of curved shell-supported footbridges has been performed using a Particle-Spring System and Thrust Network Analysis. Finally, the form-finding of curved shell-supported footbridges subjected to both vertical and horizontal forces (i.e. earthquake action) has been implemented

Curved footbridges supported by a shell obtained through thrust network analysis

After Maillart's concrete curved arch bridges were built before the Second World War, in the second half of the past century and this century, many curved bridges have been built with both steel and concrete. Conversely, since the construction of Musmeci's shell supported bridge in Potenza, few shell bridges have been constructed. This paper explains how to design a curved footbridge supported by an anticlastic shell by shaping the shell via a thrust network analysis (TNA). By taking advantage of the peculiar properties of anticlastic membranes, the unconventional method of shaping a shell by a TNA is illustrated. The shell top edge that supports the deck has an assigned layout, which is provided by the road curved layout. The form of the bottom edge is obtained by the form-finding procedure as a thrust line, by applying the thrust network analysis (TNA) in a non-standard manner, shaping the shell by applying the boundary conditions and allowing relaxation. The influence of the boundary conditions on the bridge shape obtained as an envelope of thrust lines is investigated. A finite element analysis was performed. The results indicate that the obtained shell form is effective in transferring deck loads to foundations via compressive stresses and taking advantage of concrete mechanical properties

energetic and economic analysis of a new concept of solar concentrator for residential application

Abstract Renewable energy penetration is increasing in last years, covering a more and more important role in both electrical and thermal supply. Nowadays, the photovoltaic conversion is a consolidated technology and can be efficiently combined with solar concentration. In this study, a new concept of photovoltaic solar concentrator based on non-conventional mirrors coupled with high efficiency triple-junctions cells is described and discussed. More in details, as for the optical design, deformations are applied to classical spherical mirrors to control solar aberrations and boost efficiency of a receiver consisting in a dense array of cells. The efficiency enhance is obtained by high matching between the collected solar irradiance and the receiver electrical features. The concentrator is able to produce both electrical and thermal energy: the system requires in fact an active cooling circuit to maintain the cells performance. This behavior makes the system suitable for combined heat and power applications with particular reference to high direct irradiance environments. An analytical study, considering a residential utility has been performed in order to understand the energetic and economic performance of the system. In particular, a simulation has been carried out by the use of an in-house-developed calculation code considering a whole year of operation