A comparative study of the estimators for the demand of engineering courses in Portugal

For the purpose of modeling the demand of Engineering Courses in Portugal we analyzed the possible regression models for panel count data models by establishing a comparison between the estimators obtained and then finding the most appropriate ones for our dataset. A precise quantification of the demand for each academic program is facilitated by the rules of access to higher education, in National Contest for Access and Admission to Higher Education, where candidates must list up to six preferences of institution and program. The data used in this paper covers the results of the national contest from 1997 to 2015 provided by the Portuguese Ministry of Education and Science. Multivariate methodologies were performed in order to allow a better understanding of the students’ allocation behavior. The results seem to indicate that the negative binomial estimates fit better the dataset analyzed.A. Manuela Gonc¸alves and Raquel Oliveira were supported by the Research Centre of Mathematics of the University of Minho with the Portuguese Funds from the ”FCT Fundac¸ao para a Ci ˜ encia e a Tecnologia”, through the Project PEstOE/MAT/UI0013/2014. Rosa ˆ M. Vasconcelos was supported by the Foundation through ”FCT - Fundac¸ao para a Ci ˜ encia e Tec- ˆ nologia”, within the Project UID/MAT/00013/2013, by FEDER funds through the Competitivity Factors Operational Programme - COMPET and by national funds through FCT within the scope of the project POCI-01-0145-FEDER-007136

The process of EDC-NHS Cross-linking of reconstituted collagen fibres increases collagen fibrillar order and alignment.

We describe the production of collagen fibre bundles through a multi-strand, semi-continuous extrusion process. Cross-linking using an EDC (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide), NHS (N-hydroxysuccinimide) combination was considered. Atomic Force Microscopy (AFM) and Raman spectroscopy focused on how cross-linking affected the collagen fibrillar structure. In the cross-linked fibres, a clear fibrillar structure comparable to native collagen was observed which was not observed in the non-cross-linked fibre. The amide III doublet in the Raman spectra provided additional evidence of alignment in the cross-linked fibres. Raman spectroscopy also indicated no residual polyethylene glycol (from the fibre forming buffer) or water in any of the fibres.The authors would like to acknowledge the support of the Engineering and Physical Sciences Research Council (EPSRC), UK through a Knowledge Transfer Secondment (KTS) (to JHS), The National Institute for Health Research (NIHR) through their i4i grant to Tigenix Ltd and the TSB grant TP/8/BIO/6/I/Q0052.This is the accepted manuscript. The final version is available from AIP at http://scitation.aip.org/content/aip/journal/aplmater/3/1/10.1063/1.4900887

Optimization of a therapeutic electromagnetic field (EMF) to retard breast cancer tumor growth and vascularity

BACKGROUND: This study provided additional data on the effects of a therapeutic electromagnetic field (EMF) device on growth and vascularization of murine 16/C mammary adenocarcinoma cells implanted in C3H/HeJ mice. METHODS: The therapeutic EMF device generated a defined 120 Hz semi sine wave pulse signal of variable intensity. Murine 16/C mammary adenocarcinoma tumor fragments were implanted subcutaneously between the scapulae of syngeneic C3H mice. Once the tumor grew to 100 mm(3), daily EMF treatments were started by placing the cage of mice within the EMF field. Treatment ranged from 10 to 20 milli-Tesla (mT) and was given for 3 to 80 minutes either once or twice a day for 12 days. Tumors were measured and volumes calculated each 3–4 days. RESULTS: Therapeutic EMF treatment significantly suppressed tumor growth in all 7 EMF treated groups. Exposure to 20mT for 10 minutes twice a day was the most effective tumor growth suppressor. The effect of EMF treatment on extent of tumor vascularization, necrosis and viable area was determined after euthanasia. The EMF reduced the vascular (CD31 immunohistochemically positive) volume fraction and increased the necrotic volume of the tumor. Treatment with 15 mT for 10 min/d gave the maximum anti-angiogenic effect. Lack of a significant correlation between tumor CD 31 positive area and tumor growth rate indicates a mechanism for suppression of tumor growth in addition to suppression of tumor vascularization. CONCLUSION: It is proposed that EMF therapy aimed at suppression of tumor growth and vascularization may prove a safe alternative for patients whether they are or are not candidates for conventional cancer therapy

New type of microengine using internal combustion of hydrogen and oxygen

Microsystems become part of everyday life but their application is restricted by lack of strong and fast motors (actuators) converting energy into motion. For example, widespread internal combustion engines cannot be scaled down because combustion reactions are quenched in a small space. Here we present an actuator with the dimensions 100x100x5 um^3 that is using internal combustion of hydrogen and oxygen as part of its working cycle. Water electrolysis driven by short voltage pulses creates an extra pressure of 0.5-4 bar for a time of 100-400 us in a chamber closed by a flexible membrane. When the pulses are switched off this pressure is released even faster allowing production of mechanical work in short cycles. We provide arguments that this unexpectedly fast pressure decrease is due to spontaneous combustion of the gases in the chamber. This actuator is the first step to truly microscopic combustion engines.Comment: Paper and Supplementary Information (to appear in Scientific Reports

Fuzzy modelling of acid mine drainage environments using geochemical, ecological and mineralogical indicators

Fuzzy logic was applied to model acid mine drainage (AMD) and to obtain a classification index of the environmental impact in a contaminated riverine system. The data set used to develop this fuzzy model (a fuzzy classifier) concerns an abandoned mine in Northern Portugal— Valdarcas mining site. Here, distinctive drainage environments (spatial patterns) can be observed based on the AMD formed in the sulphide-rich waste-dumps. Such environments were established, as the effluent flows through the mining area, using several kinds of indicators. These are physical–chemical, ecological and mineralogical parameters, being expressed in a quantitative or qualitative basis. The fuzzy classifier proposed in this paper is a min– max fuzzy inference system, representing the spatial behaviour of those indicators, using the AMD environments as patterns. As they represent different levels (classes) of contamination, the fuzzy classifier can be used as a tool, allowing a more reasonable approach, compared with classical models, to characterize the environmental impact caused by AMD. In a general way it can be applied to other sites where sulphide-rich waste-dumps are promoting the pollution of superficial water through the generation of AMD

Protocol for a novel sodium and blood pressure reduction intervention targeting online grocery shoppers with hypertension – the SaltSwitch Online Grocery Shopping randomized trial

Background: High dietary sodium intake is a leading cause of hypertension. A major source of dietary sodium is salt added to processed food products available in retail food environments. The fast-growing online grocery shopping setting provides new opportunities for salt reduction interventions that support consumers in choosing healthier options. Methods: The SaltSwitch Online Grocery Shopping randomized controlled trial is investigating the feasibility, acceptability, and effectiveness of a novel intervention for lowering salt consumption and blood pressure amongst people with hypertension who shop for groceries online. The intervention is based on a bespoke web browser extension that interfaces with a major retailer's online store to highlight and interpret product sodium content and suggest similar but lower-sodium alternatives. The primary outcome of interest is change in mean systolic blood pressure between individuals randomized (1:1) to the intervention and control (usual online shopping) arms at 12 weeks. Secondary outcomes are diastolic blood pressure, spot urinary sodium and sodium:potassium ratio, sodium purchases, and dietary intake. Intervention implementation and lessons for future uptake will be assessed using a mixed methods process evaluation. Participants with hypertension who shop online for groceries and exhibit high sodium purchasing behavior are being recruited across Australia. A target sample size of 1,966 provides 80% power (2-sided alpha = 0.05) to detect a 2 mm Hg difference in systolic blood pressure between groups, assuming a 15 mm Hg standard deviation, after allowing for a 10% dropout rate. Discussion: This trial will provide evidence on an innovative intervention to potentially reduce salt intake and blood pressure in people with hypertension. The intervention caters to individual preferences by encouraging sustainable switches to similar but lower-salt products. If effective, the intervention will be readily scalable at low cost by interfacing with existing online retail environments