Assessing the Usability of a Visual Tool for the definition of E-learning Processes

In this paper, we present a usability study aiming at assessing a visual language-based tool for developing adaptive e-learning processes. The tool implements the adaptive self-consistent learning object SET (ASCLO-S) visual language, a special case of flow diagrams, to be used by instructional designers to define classes of learners through stereotypes and to specify the more suited adaptive learning process for each class of learners. The usability study is based on the combined use of two techniques: a questionnaire-based survey and an empirical analysis. The survey has been used to achieve feedbacks from the subjects' point of view. In particular, it has been useful to capture the perceived usability of the subjects. The outcomes show that both the proposed visual notation and the system prototype are suitable for instructional designers with or without experience on the computer usage and on tools for defining e-learning processes. This result is further confirmed by the empirical analysis we carried out by analysing the correlation between the effort to develop adaptive e-learning processes and some measures suitable defined for those processes. Indeed, the empirical analysis revealed that the effort required to model e-learning processes is not influenced by the experience of the instructional designer with the use of e-learning tools, but it only depends on the size of the developed process

Primary Absence of Type II Endoleak is A Positive Prognostic Factor against the Risk of Late Conversion of EVAR for AAA

Introduction: The aim of this study is to analyze 12 late conversion to open surgery after Endovascular Repair of Abdominal Aortic Aneurysms (EVAR) while comparing the follow up of these cases to that of the definitely successful procedures (absence of surgical conversion, type I or III endoleaks, or presence of type II endoleaks without any aneurysmal sac enlargement) . Methods: From a series of over 300 EVAR procedures performed at our department we have selected 215 cases with a follow up ≥ 6 month and primary technical success (successful deployment of the devices and discharge of patients without neither type I nor III endoleaks). Based on the final data recorded at the end of the follow up (mean+ IQR: 38.16 months + 41), these cases were divided into three groups: group 1, with 12 cases (5.6%) which needed surgical conversion in a later stage (5 to 55 months from EVAR); group 2, with 39 cases (18.1%) with type II endoleaks without aneurysmal sac enlargement; group 3, with 164 cases (76.5%) without endoleaks. The groups were compared in relation to the following parameters: a) personal data and common atherogenic risk factor, b) diameter of the aneurysm, c) kind of the proximal fixation of the endograft (suprarenal or infrarenal), d) presence of endoleaks at the first postoperative check. We have compared the data from the three groups and we have analyzed them with chi-square test (Χ2). Results: Personal data and common atherogenic risk factor have proved no significant difference among the three groups. The incidence of the other three parameters of group 1 was compared with the incidence of these in groups 2 and 3: the mean pre-operative diameter of the aneurysm results 51 mm in group 1, 54 mm in group 2 and 55 mm in group 3 (not significant); suprarenal fixation of the prosthesis accounts for 50% in group 1, 51% in group 2 and 60% in group 3 (not significant); presence of type II endoleak at the first post-operative check was 41.6% in group 1, 56.4% in group 2 (not significant) and 9.7% in group 3 (p<0.001, compared to groups 1 and 2). Conclusion: In the EVAR procedures with primary technical success, the absence of type II endoleak at the first post-operative check represents a favorable prognostic factor against the risk of late conversion to open repair. Personal data, common atherogenic risk factor, diameter of the aneurysm and fixing type of the prosthesis don’t seem to influence the onset of this complication

Life Satisfaction in Retirees Who are still Working 1

Retirement does not always represent the final exit from the labor market. Work is one of the most important aspects in people’s lives, and a relationship seems to exist between continuity of work during retirement and life satisfaction. This study evaluated the perception of life satisfaction among 230 retirees who were still working. Participants completed a questionnaire containing scales for Life Satisfaction, Job Perception and Reasons for Returning to Work. Correlations and multiple linear regression indicated that perception of the work, satisfaction with income and intrinsic reasons (such as the feeling of productivity) influenced life satisfaction of retirees who returned to work. Our results reinforce the adoption of public and organizational policies to maintain retirees who wish to continue working.Nem sempre a aposentadoria significa a saída definitiva do mercado de trabalho. O trabalho é um dos aspectos mais relevantes na vida das pessoas adultas e parece haver uma relação entre a continuidade do trabalho durante a aposentadoria e a satisfação com a vida. Este estudo avaliou a percepção de 230 aposentados que ainda estavam trabalhando e a satisfação com suas vidas. Os participantes responderam a um questionário contendo escalas de Satisfação com a Vida, Percepção do Trabalho e Motivos para o Retorno ao Trabalho. As correlações e a regressão linear múltipla apontaram que a percepção do trabalho, a satisfação com a renda e os motivos intrínsecos, como o sentimento de produtividade, influenciaram a satisfação com a vida desses aposentados que retornaram ao trabalho. Tais resultados apontam para a necessidade de políticas públicas e organizacionais visando a retenção de aposentados que desejam permanecer trabalhando.La jubilación no siempre representa la salida definitiva del mercado laboral. El trabajo es uno de los aspectos más importantes en la vida de las personas adultas y parece haber una relación entre la continuidad del trabajo durante la jubilación y la satisfacción con la vida. Este estudio evaluó la percepción de 230 jubilados que aun trabajan y su satisfacción con la vida. Los participantes respondieron a un cuestionario que contiene las escalas de Satisfacción con la Vida, Percepción del Trabajo y Razones para el Regreso al Trabajo. Las correlaciones y la regresión linear múltiple, demostraron que la percepción del trabajo, la satisfacción con la renta y las razones intrínsecas - como la sensación de la productividad - influyeron en la satisfacción con la vida de estos jubilados. Estos resultados refuerzan la necesidad de políticas públicas y organizacionales que permitan la permanencia de jubilados que deseen seguir trabajando

An In-Silico Pipeline for Rapid Screening of DNA Aptamers against Mycotoxins: The Case-Study of Fumonisin B1, Aflatoxin B1 and Ochratoxin A

Aptamers are single-stranded oligonucleotides selected by SELEX (Systematic Evolution of Ligands by EXponential Enrichment) able to discriminate target molecules with high affinity and specificity, even in the case of very closely related structures. Aptamers have been produced for several targets including small molecules like mycotoxins; however, the high affinity for their respective target molecules is a critical requirement. In the last decade, the screening through computational methods of aptamers for their affinity against specific targets has greatly increased and is becoming a commonly used procedure due to its convenience and low costs. This paper describes an in-silico approach for rapid screening of ten ssDNA aptamer sequences against fumonisin B1 (FB1, n = 3), aflatoxin B1 (AFB1, n = 2) and ochratoxin A (OTA, n = 5). Theoretical results were compared with those obtained by testing the same aptamers by fluorescent microscale thermophoresis and by magnetic beads assay for their binding affinity (KD) revealing a good agreement

Detection of water at z = 0.685 towards B0218+357

We report the detection of the H_2O molecule in absorption at a redshift z = 0.68466 in front of the gravitationally lensed quasar B0218+357. We detect the fundamental transition of ortho-water at 556.93 GHz (redshifted to 330.59 GHz). The line is highly optically thick and relatively wide (15 km/s FWHM), with a profile that is similar to that of the previously detected CO(2--1) and HCO^+(2--1) optically thick absorption lines toward this quasar. From the measured level of the continuum at 330.59 GHz, which corresponds to the level expected from the power-law spectrum $S(\nu) \propto \nu^{-0.25}$ already observed at lower frequencies, we deduce that the filling factor of the H_2O absorption is large. It was already known from the high optical thickness of the CO, ^{13}CO and C^{18}O lines that the molecular clouds entirely cover one of the two lensed images of the quasar (all its continuum is absorbed); our present results indicate that the H_2O clouds are covering a comparable surface. The H_2O molecules are therefore not confined to small cores with a tiny filling factor, but are extended over parsec scales. The H_2O line has a very large optical depth, and only isotopic lines could give us the water abundance. We have also searched for the 183 GHz line in absorption, obtaining only an upper limit; this yields constraints on the excitation temperature.Comment: 4 pages, 3 figures, accepted in ApJ Letter

Study of the time and space distribution of beta+ emitters from 80 MeV/u carbon ion beam irradiation on PMMA

Proton and carbon ion therapy is an emerging technique used for the treatment of solid cancers. The monitoring of the dose delivered during such treatments and the on-line knowledge of the Bragg peak position is still a matter of research. A possible technique exploits the collinear 511\ \kilo\electronvolt photons produced by positrons annihilation from $\beta^+$ emitters created by the beam. This paper reports rate measurements of the 511\ \kilo\electronvolt photons emitted after the interactions of a 80\ \mega\electronvolt / u fully stripped carbon ion beam at the Laboratori Nazionali del Sud (LNS) of INFN, with a Poly-methyl methacrylate target. The time evolution of the $\beta^+$ rate was parametrized and the dominance of $^{11}C$ emitters over the other species ($^{13}N$, $^{15}O$, $^{14}O$) was observed, measuring the fraction of carbon ions activating $\beta^+$ emitters $A_0=(10.3\pm0.7)\cdot10^{-3}$. The average depth in the PMMA of the positron annihilation from $\beta^+$ emitters was also measured, D_{\beta^+}=5.3\pm1.1\ \milli\meter, to be compared to the expected Bragg peak depth D_{Bragg}=11.0\pm 0.5\ \milli\meter obtained from simulations

Precision Measurement of KS Meson Lifetime with the KLOE detector

Using a large sample of pure, slow, short lived K0 mesons collected with KLOE detector at DaFne, we have measured the KS lifetime. From a fit to the proper time distribution we find tau = (89.562 +- 0.029_stat +- 0.043_syst) ps. This is the most precise measurement today in good agreement with the world average derived from previous measurements. We observe no dependence of the lifetime on the direction of the Ks.Comment: 5 pages, 7 figure