Application of a virtual scientific experiment model in different educational contexts

E-learning practice is continuously using experimentation in order to enhance the basic information transfer model where knowledge is passed from the system/ tutors to the students. Boosting student productivity through on-line experimentation is not simple since many organizational, educational and technological issues need to be dealt with. This work describes the application of a Learning Model for Virtual Scientific Experiments (VSEs) in two different scenarios: Information and Communication Technologies and Physics. As part of the first, a VSE for Wireless Sensor Networks was specified and deployed while the second involved the specification and design of a collaborative VSE for physics experiments. Preliminary implementation and deployment results are also discussed

Stock Selection System: Building Long/Short Portfolios Using Intraday Patterns

AbstractWe present the architecture of a complete intraday trading management system using a stock selection algorithm for building long/short portfolios. Our approach for stock selection is based on knowledge discovery in large databases technologies; more specifically, we build techniques that allow one to discover hidden price patterns which are capable of predicting the direction of stock prices. The base of the whole system is a novel pattern mining algorithm from time-series data, which involves highly compute-intensive aggregation calculations as complex but efficient distributed SQL queries on the relational databases that store the time-series. This algorithm follows similar path to Association Rule Mining algorithms (such as the Apriori and FP-Growth algorithms) but with major differences. First, it has one step more at initialization which uses a rule-based generator algorithm that transforms relations and data structures in a binary string format. These patterns contain mixed information of small price patterns (3, 4 or 5 candlesticks) and trading signals/filters produced by technical indicators. As output, instead of generating association rules, it produces probabilities (varies between 60% and 95%) about the future stock price direction such as “within next 5 periods, price will increase (or decrease) more than 2%”. Then, the stock selection system exploits all this information and uses it to find those stocks that appear to form patterns which have the highest accuracy in predicting prices. Each time period (finest interval length being 10minutes), the stock selector system, having the support of trading systems, examines and decides which stocks should be replaced in current portfolio by other more profitable stocks. The system testing, which produced interested results, is made of portfolio of 10 stocks having open long position and 5 stocks having open short positions

DEVELOPING HUMAN RESOURCES’ SKILLS AND KNOWLEDGE IN TOURISM AND HOSPITALITY INDUSTRY THROUGH THE DETERMINATION OF QUALITY OF TRAINING PROGRAMS

Research into tourism and hospitality training field has been focused on the subjects of training need assessments, training evaluation models, training within organizational frameworks and useful training techniques. Despite the significance of the above aspects, less afford has been made in the field of training quality and particularly in defining those factors that the quality of a training program consists of. Taking into account that training is a service which the organization, the producer, delivers to its employee, the consumer, this research is going one step further and not only exams SERVQUAL in the training field, but tries to examine inductively at distinctive training quality dimensions from the perspective of trainees point of view that are not subject of other service industry. The definition of training quality dimensions can lead those who develop a new training program to use those dimensions as a framework for greater training outcomes. Moreover, this research tests how the GAP model is compared with the measurement of perceptions merely and the measurement of expectations lone of training quality, as defined by the trainees

Electroretinogram changes before and after silicone oil removal in eyes with macula-off rhegmatogenous retinal detachment

Background: Pars plana vitrectomy (PPV) with silicone oil (SO) injection for rhegmatogenous retinal detachment (RRD) repair may adversely affect electroretinographic responses. This study was aimed at assessing retinal function using electrodiagnostic testing after successful PPV with SO tamponade in the eyes with macula-off RRD. Methods: In this interventional comparative study, eligible participants were recruited prospectively over 1 year. We included the eyes that underwent a single successful three-port PPV with SO tamponade for the primary repair of macula-off RRD. Full-field electroretinogram (ffERG) and multifocal electroretinogram (mfERG) were recorded 1 day before and 3 days after SO removal. The amplitude and implicit time of the a- and b-waves for ffERG and P1 and N1 waves for mfERG were evaluated. The unaffected fellow eyes of the patients were selected as controls. Results: We included the ten eyes of ten patients (seven men and three women) with a mean (standard deviation) age of 58.8 (6.2) years. The mean (SD) interval between the diagnoses of macula-off RRD and PPV was 11.7 (3.6) days. The mean (SD) duration of SO tamponade was 147.8 (34.9) days. Using ffERG, significantly lower a- and b-wave amplitudes were found in the eyes before and after SO removal or compared to the unaffected fellow eyes (all P < 0.05). Using the mfERG, treated eyes had significantly lower P1 amplitudes in the central R1+R2+R3 rings and in the R4 and-R5 peripheral rings of the macular area in the eyes before and after SO removal or compared to the unaffected fellow eyes (all P < 0.05). The wave implicit time in ffERG and mfERG did not differ significantly in the eyes before and after SO removal or compared to the unaffected fellow eyes (all P > 0.05). Conclusions: The electrical retinal response density in ERG waveforms increased following SO removal, indicating amelioration of the electrical activity of the retina and macula. These results indicate that the adverse effects of SO tamponade on electroretinography responses may be reversible with removal. In addition, ffERG and mfERG can be used to monitor retinal function in the eyes with macula-off RRD and SO tamponade. Further clinical trials are required to verify the preliminary findings of this study

Living with satisfactory vision and no comorbidity 28 years after bilateral retinoblastoma: a case report and mini literature review

Background: Retinoblastoma is the most common primary intraocular malignancy in children, although it is a rare neural retinal tumor. Improving the quality of life is the next goal after the primary medical goal of life preservation. The genotype-phenotype correlation may vary with the progression of retinoblastoma. Expressivity is determined by different RB1 gene mutations among individuals. Herein, we share our experience on the evaluation of the long-term progression of retinoblastoma, its treatment consequences, its impact on the quality of life, and how the underlying genotypes are related to the phenotypes. We provide a review of the relevant literature and present a case of a sporadic heritable bilateral retinoblastoma. Case Presentation: We report the outcomes of a 28-year follow-up of a female diagnosed with an infantile disease. The patient’s best eye, according to the tumor classification and genetic results, was treated conservatively whereas the worst eye was enucleated. On re-examinations, she had complications of the treatment she received. Therefore, another intervention was administered for several years. The patient’s pathogenic variant and RB1 gene mutational inactivation were predispositions to the recurrence of the tumor and non-ocular primary malignancy. Nevertheless, the disease had no progression. The patient is stable despite her type of retinoblastoma, which is the sporadic heritable bilateral form. Conclusions: Each phenotype of bilateral retinoblastoma varies in progression. The nature of the genetic mutation may determine its expressivity. It is of great significance to individualize every decision. In each case, the sequelae of the disease and treatment-induced complications may have an impact on the quality of the patient’s life

Effects of a hops (Humulus lupulus L.) dry extract supplement on self-reported depression, anxiety and stress levels in apparently healthy young adults:a randomized, placebo-controlled, double-blind, crossover pilot study

OBJECTIVE: The Humulus lupulus L. plant (hops) is used as a herbal medicinal product for anxiety/mood disorders. Our aim was to study the effects of a hops dry extract on self-reported depression, anxiety and stress levels in young adults. DESIGN: Apparently healthy young adults from our university completed the Depression Anxiety Stress Scale-21 (DASS-21) and those reporting at least mild depression, anxiety and stress were invited to complete the study intervention. This followed a randomized (1:1), placebo-controlled, double-blind, crossover design with two 4-week intervention periods (hops or placebo; two 0.2 gr capsules once daily) separated by a 2-week wash-out. Anthropometric measurements, DASS-21 assessments and measurements of morning cortisol plasma levels were performed at the beginning and the end of the 4-week treatment periods. RESULTS: 36 participants (Females/Males: 31/5; age: 24.7±0.5 years) completed the study intervention (attrition: 6/42). No significant changes in body weight and composition or morning circulating cortisol were noted with the hops or placebo. Significantly decreased DASS-21 anxiety, depression and stress scores were documented with hops (9.2±7.3 vs. 5.1±5.9, 11.9±7.9 vs. 9.2±7.4, and 19.1±8.1 vs. 11.6±8.1; all p values <0.05), which were significantly greater compared to those caused by the placebo (all p values <0.05). CONCLUSION: In otherwise healthy young adults reporting at least mild depression, anxiety and stress symptoms, daily supplementation with a hops dry extract can significantly improve all these symptoms over a 4-week period. These beneficial effects agree with the indication of hops for anxiety/mood disorders and restlessness, as approved by the German Commission E

Microscopic Theory for the Markovian Decay of Magnetization Fluctuations in Nanomagnets

We present a microscopic theory for the phonon-driven decay of the magnetization fluctuations in a wide class of nanomagnets where the dominant energy is set by isotropic exchange and/or uniaxial anisotropy. Based on the Zwanzig-Mori projection formalism, the theory reveals that the magnetization fluctuations are governed by a single decay rate $\omega_c$, which we further identify with the zero-frequency portion of the associated self-energy. This dynamical decoupling from the remaining slow degrees of freedom is attributed to a conservation law and the discreteness of the energy spectrum, and explains the omnipresent mono-exponential decay of the magnetization over several decades in time, as observed experimentally. A physically transparent analytical expression for $\omega_c$ is derived which highlights the three specific mechanisms of the slowing down effect which are known so far in nanomagnets.Comment: 7 page