Quantity-setting competition under uncertain demand

We consider a quantity-setting duopoly model, and we study the decision to move first or second, by assuming that. the firms produce homogeneous goods and that. there is some demand uncertainty. The competitive phase consists of two periods, and in either period, the firms can make a production decision that is irreversible. As far as the firms are allowed to choose (non-cooperatively) the period they make the decision, we study the circumstances that favour sequential rather than simultaneous decisions.

Dificuldades de prendizagem na quisição da leitura: um estudo de caso

A aprendizagem da leitura e da escrita consiste num dos maiores desafios que as crianças têm de enfrentar no início da sua escolarização. Conseguir vencer esse desafio dá-lhes a oportunidade de se tornarem cidadãos livres, autónomos e informados (Silva, 2003). Contudo, o ato de ler pode tornar-se um desafio árduo de atingir, com muitas dificuldades pelo meio, podendo exigir bastante sensibilidade, conhecimento, informação e até arte por parte de quem ensina. Sabemos que a informação não chega a todos os alunos da mesma forma. Uns necessitam de mais tempo para aprender, mais oportunidades, outras estratégias. Este trabalho teve como objetivo principal encontrar um conjunto de estratégias que fossem ao encontro das necessidades educativas de uma aluna com oito anos de idade que revela grandes dificuldades na aquisição desta competência. Numa primeira fase da intervenção foram aplicadas provas diagnósticas para aferir as aquisições que a aluna já tinha feito de modo a delinear uma intervenção eficaz e motivadora que fosse ao encontro das suas necessidades. A intervenção baseou-se na aplicação de um método multissensorial que trabalhasse todos os mecanismos inerentes ao ato de ler. Esperava-se que com esta intervenção a aluna lesse e escrevesse pequenas frases, tendo adquirido a base para o desenvolvimento da leitura. Os resultados obtidos foram positivos, sendo que os fonemas trabalhados foram adquiridos, tendo chegado a aluna ao fim da intervenção a ler frases simples

Standard commercial education robotic platform: intermediate solution to teaching robotics

Teaching robotics to students at the beginning of their studies has become a huge challenge. Simulation environments can be an effective solution to that challenge where students can interact with simulated robots and have the first contact with robotic constraints. From our previous experience with simulation environments it was possible to observe that students with lower background knowledge in robotics where able to deal with a limited number of constraints, implement a simulated robotic platform and study several sensors. The question is: after this first phase what should be the best approach? Should the student start developing their own hardware? Hardware development is a very important part of an engineer's education but it can also be a difficult phase that could lead to discouragement and loss of motivation in some students. Considering the previous constraints and first year engineering students’ high abandonment rate it is important to develop teaching strategies to deal with this problem in a feasible way. The solution that we propose is the integration of a low-cost standard robotic platform WowWee Rovio as an intermediate solution between the simulation phase and the stage where the students can develop their own robots. This approach will allow the students to keep working in robotic areas such as: cooperative behaviour, perception, navigation and data fusion. The propose approach proved to be a motivation step not only for the students but also for the teachers. Students and teachers were able to reach an agreement between the level of demand imposed by the teachers and satisfaction/motivation of the students.

Stackelberg duopoly with demand uncertainty

We consider a symmetric Stackelberg model in which there is asymmetric demand information owned by first and second movers. We analyse the advantages of leadership and flexibility, and prove that when the leading firm faces demand uncertainty, but the follower does not, the first mover does not necessarily have advantage over the second mover. Moreover, we show that the advantage of one firm over the other depends upon the demand fluctuation and also upon the degree of substitutability of the products.

Is mental practice an effective adjunct therapeutic strategy for upper limb motor restoration after stroke? A systematic review and meta- analysis

Stroke is one of the most common conditions requiring rehabilitation, and its motor impairments are a major cause of permanent disability. Hemiparesis is observed by 80% of the patients after acute stroke. Neuroimaging studies showed that real and imagined movements have similarities regarding brain activation, supplying evidence that those similarities are based on the same process. Within this context, the combination of mental practice (MP) with physical and occupational therapy appears to be a natural complement based on neurorehabilitation concepts. Our study seeks to investigate if MP for stroke rehabilitation of upper limbs is an effective adjunct therapy. PubMed (Medline), ISI knowledge (Institute for Scientific Information) and SciELO (Scientific Electronic Library) were terminated on 20 February 2015. Data were collected on variables as follows: sample size, type of supervision, configuration of mental practice, setting the physical practice (intensity, number of sets and repetitions, duration of contractions, rest interval between sets, weekly and total duration), measures of sensorimotor deficits used in the main studies and significant results. Random effects models were used that take into account the variance within and between studies. Seven articles were selected. As there was no statistically significant difference between the two groups (MP vs control), showed a - 0.6 (95% CI: -1.27 to 0.04), for upper limb motor restoration after stroke. The present meta-analysis concluded that MP is not effective as adjunct therapeutic strategy for upper limb motor restoration after stroke.

From Mind to Body: Is Mental Practice Effective on Strength Gains? A Meta-Analysis

Mental practice is an internal reproduction of a motor act (whose intention is to promote learning and improving motor skills). Some studies have shown that other cognitive strategies also increase the strength and muscular resistance in healthy people by the enhancement of the performance during dynamic tasks. Mental training sessions may be primordial to improving muscle strength in different subjects. The aim of this study was to systematically review and meta-analiyze studies that assessed whether mental practice is effective in improving muscular strength. We conducted an electronic-computed search in Pub-Med/Medline and ISI Web of Knowledge, Scielo and manual searchs, searching papers written in English between 1991 and 2014. There were 44 studies in Pub-Med/Medline, 631 in ISI Web of Knowledge, 11 in Scielo and 3 in manual searchs databases. After exclusion of studies for duplicate, unrelated to the topic by title and summary, different samples and methodologies, a meta-analysis of 4 studies was carried out to identify the dose-response relationship. We did not find evidence that mental practice is effective in increasing strength in healthy individuals. There is no evidence that mental practice alone can be effective to induce strength gains or to optimize the training effects.

Flexibility and leadership advantages in a model with uncertain demand

We consider a differentiated Stackelberg model with demand uncertainty only for the first mover. We study the advantages of flexibility over leadership as the degree of the differentiation of the goods changes.

Demand Response Programs Design and Use Considering Intensive Penetration of Distributed Generation

Further improvements in demand response programs implementation are needed in order to take full advantage of this resource, namely for the participation in energy and reserve market products, requiring adequate aggregation and remuneration of small size resources. The present paper focuses on SPIDER, a demand response simulation that has been improved in order to simulate demand response, including realistic power system simulation. For illustration of the simulator’s capabilities, the present paper is proposes a methodology focusing on the aggregation of consumers and generators, providing adequate tolls for the demand response program’s adoption by evolved players. The methodology proposed in the present paper focuses on a Virtual Power Player that manages and aggregates the available demand response and distributed generation resources in order to satisfy the required electrical energy demand and reserve. The aggregation of resources is addressed by the use of clustering algorithms, and operation costs for the VPP are minimized. The presented case study is based on a set of 32 consumers and 66 distributed generation units, running on 180 distinct operation scenarios.

A multi-objective model for scheduling of short-term incentive-based demand response programs offered by electricity retailers

In this paper, we formulate the electricity retailers’ short-term decision-making problem in a liberalized retail market as a multi-objective optimization model. Retailers with light physical assets, such as generation and storage units in the distribution network, are considered. Following advances in smart grid technologies, electricity retailers are becoming able to employ incentive-based demand response (DR) programs in addition to their physical assets to effectively manage the risks of market price and load variations. In this model, the DR scheduling is performed simultaneously with the dispatch of generation and storage units. The ultimate goal is to find the optimal values of the hourly financial incentives offered to the end-users. The proposed model considers the capacity obligations imposed on retailers by the grid operator. The profit seeking retailer also has the objective to minimize the peak demand to avoid the high capacity charges in form of grid tariffs or penalties. The non-dominated sorting genetic algorithm II (NSGA-II) is used to solve the multi-objective problem. It is a fast and elitist multi-objective evolutionary algorithm. A case study is solved to illustrate the efficient performance of the proposed methodology. Simulation results show the effectiveness of the model for designing the incentive-based DR programs and indicate the efficiency of NSGA-II in solving the retailers’ multi-objective problem.

Effective swimmer’s action during the grab start technique

The external forces applied in swimming starts have been often studied, but using direct analysis and simple interpretation data processes. This study aimed to develop a tool for vertical and horizontal force assessment based on the swimmers' propulsive and structural forces (passive forces due to dead weight) applied during the block phase. Four methodological pathways were followed: the experimented fall of a rigid body, the swimmers' inertia effect, the development of a mathematical model to describe the outcome of the rigid body fall and its generalization to include the effects of the inertia, and the experimental swimmers' starting protocol analysed with the inclusion of the developed mathematical tool. The first three methodological steps resulted in the description and computation of the passive force components. At the fourth step, six well-trained swimmers performed three 15 m maximal grab start trials and three-dimensional (3D) kinetic data were obtained using a six degrees of freedom force plate. The passive force contribution to the start performance obtained from the model was subtracted from the experimental force due to the swimmers resulting in the swimmers' active forces. As expected, the swimmers' vertical and horizontal active forces accounted for the maximum variability contribution of the experimental forces. It was found that the active force profile for the vertical and horizontal components resembled one another. These findings should be considered in clarifying the active swimmers' force variability and the respective geometrical profile as indicators to redefine steering strategies.

Perinatal Bacterial Infection: Screenning of Vertical Transmitted Infections

Perinatal bacterial infection may be caused by any microorganism colonizing the vaginal tract. Neonatologists and paediatricians are especially concerned about group B Stretpococcus (GBS). However, Enterobactereacea, mainly E.coli and Proteus, are also responsible for infection. GBS screening may be accomplished in over 90% of pregnant women. In our maternity in 2007-2008, 85% of the mothers had been screened. Screening and prophylaxis were responsible for a decreasing incidence of neonatal infection - from 0.6/1000 to 0.15/1000 live births in Portugal, from 2002 to 2007. However there are some difficulties related to screening. In the second Portuguese study 16/57 NB with early-onset infection (28%) were born to “negative” mothers. Several factors illustrate how difficult is to draw national screening policies: a wide range of carrier’s state rate throughout a country - in Portugal from 12% to 30%. The success of any screening policy may also be affected by additional technical and organizational problems. In countries where home delivery is a tradition or a trend intrapartum GBS prophylaxis requires a very well organized assistance.. Moreover factors usually accepted as protective are not so effective. In the Portuguese study 24/57 infected newborns (42%) were delivery by caesarean section. Another subject deals with the workload in the postnatal ward generated by deficient compliance to the guidelines a problem not confirm by a study of our group. Decreasing the importance of GBS, highlight the importance of E. coli in perinatal infection. From the 16 340 registrations of the National Registry 1676 were newborns with mother-related infection. Applying the same reasoning to E.coli as to GBS and Listeria monocytogenes – that is considering all of them are of maternal origin - 6.7% of these infections were due to E. coli, 4.6% to SGB and 0.5% to Listeria monocytogenes. In conclusion screening and prophylaxis may be not the best way to prevent all GBS neonatal infections but by now it is the only available procedure. The other bacteria continue to demand a high suspicion level and immediate intervention.

Performance of state space and ARIMA models for consumer retail sales forecasting

Forecasting future sales is one of the most important issues that is beyond all strategic and planning decisions in effective operations of retail businesses. For profitable retail businesses, accurate demand forecasting is crucial in organizing and planning production, purchasing, transportation and labor force. Retail sales series belong to a special type of time series that typically contain trend and seasonal patterns, presenting challenges in developing effective forecasting models. This work compares the forecasting performance of state space models and ARIMA models. The forecasting performance is demonstrated through a case study of retail sales of five different categories of women footwear: Boots, Booties, Flats, Sandals and Shoes. On both methodologies the model with the minimum value of Akaike's Information Criteria for the in-sample period was selected from all admissible models for further evaluation in the out-of-sample. Both one-step and multiple-step forecasts were produced. The results show that when an automatic algorithm the overall out-of-sample forecasting performance of state space and ARIMA models evaluated via RMSE, MAE and MAPE is quite similar on both one-step and multi-step forecasts. We also conclude that state space and ARIMA produce coverage probabilities that are close to the nominal rates for both one-step and multi-step forecasts.

Thermoterapy effective and safer than miltefosine in the treatment of cutaneous leishmaniasis in Colombia

In Colombia, pentavalent antimonials and miltefosine are the drugs of choice for the treatment of cutaneous leishmaniasis; however, their toxicity, treatment duration, (treatment adherence problems), cost, and decreased parasite sensitivity make the search for alternative treatments of American cutaneous leishmaniasis necessary. Based on the results found in a controlled, open, randomized, phase III clinical trial, the efficacy and safety of miltefosine was compared to that of thermotherapy for the treatment of cutaneous leishmaniasis in Colombia. Adult patients from the Colombian army participated in the study; they received either 50 mg of miltefosine three times per day for 28 days by the oral route (n = 145) or a thermotherapy (Thermomed®) application of 50 °C for 30 seconds over the lesion and surrounding area (n = 149). Both groups were comparable with respect to their sociodemographic, clinical, and parasitological characteristics. The efficacy of miltefosine by protocol and by intention to treat was 70% (85/122 patients) and 69% (85/145 patients), respectively. The adverse effects were primarily gastrointestinal for miltefosine and pain at the lesion site after treatment for thermotherapy. No statistically significant difference was found in the efficacy analysis (intention to treat and protocol) between the two treatments. ClinicalTrials.gov: NCT00471705.

In vitro PHYTOTHERAPY OF VECTOR SNAILS BY BINARY COMBINATIONS OF LARVICIDAL ACTIVE COMPONENTS IN EFFECTIVE CONTROL OF FASCIOLIASIS

SUMMARY A food-borne trematode infection fascioliasis is one among common public health problems worldwide. It caused a great economic loss for the human race. Control of snail population below a certain threshold level is one of the important methods in the campaign to reduce the incidence of fascioliasis. The life cycle of the parasite can be interrupted by killing the snail or Fasciola larva redia and cercaria inside of the snail Lymnaea acuminata. In vitro toxicity of different binary combinations (1:1 ratio) of plant-derived larvicidal active components such as citral, ferulic acid, umbelliferone, azadirachtin and allicin against Fasciola redia and cercaria were tested. The mortality of larvae was observed at 2h, 4h, 6h and 8h of treatment. In in vitro condition azadirachtin + allicin (1:1 ratio) was highly toxic against redia and cercaria (8h LC50 0.006 and 0.005 mg/L). Toxicity of citral + ferulic acid was lowest against redia and cercaria larvae.

A Prospective Assessment of Renal Transplantation Versus Haemodialysis: Which Therapeutic Modality Is Good Value for Society?

Background: Economic evaluations help health authorities facing budget constraints. This study compares the health-related quality of life (HRQOL) and costs in patient subgroups on haemodialysis (HD) and renal transplantation (KT). Methods: In a prospective study with follow-up of 1-3 years, we performed a costutility analysis of KT vs. HD, adopting a lifetime horizon. A societal perspective was taken. Costs for organ procurement, KT eligibility, transplant surgery and follow-up of living donors were included. Key clinical events were recorded. HRQOL was assessed using the EuroQol instrument. Results: The HRQOL remained stable on HD patients. After KT, mean utility score improved at 3 months while mean EQ-VAS scores showed a sustained improvement. Mean annual cost for HD was 32,567.57€. Mean annual costs for KT in the year-1 and in subsequent years were, 60,210.09€ and 12,956.77€ respectively. Cost for initial hospitalization averaged 18,740.74€. HLA-mismatches increased costs by 75% for initial hospitalization (p < 0.001) and 41% in the year-1 (p < 0.05), and duplicate the risk of readmission in the year-1 (p < 0.05). The incremental costutility ratio was 5,534.46€/QALY, increasing 35% when costs for organ procurement were added. KT costs were 41,541.63€ more but provided additional 7.51 QALY. Conclusions: The KT is cost-effective compared with HD. Public funding should reflect the value created by the intervention and adapt to the organ demand.