A Relation-Based Page Rank Algorithm for Semantic Web Search Engines

With the tremendous growth of information available to end users through the Web, search engines come to play ever a more critical role. Nevertheless, because of their general-purpose approach, it is always less uncommon that obtained result sets provide a burden of useless pages. The next-generation Web architecture, represented by the Semantic Web, provides the layered architecture possibly allowing overcoming this limitation. Several search engines have been proposed, which allow increasing information retrieval accuracy by exploiting a key content of Semantic Web resources, that is, relations. However, in order to rank results, most of the existing solutions need to work on the whole annotated knowledge base. In this paper, we propose a relation-based page rank algorithm to be used in conjunction with Semantic Web search engines that simply relies on information that could be extracted from user queries and on annotated resources. Relevance is measured as the probability that a retrieved resource actually contains those relations whose existence was assumed by the user at the time of query definitio

Variational analysis in one and two dimensions of a frustrated spin system: chirality transitions and magnetic anisotropic transitions

We study the energy of a ferromagnetic/antiferromagnetic frustrated spin system with values on two disjoint circumferences of the 3-dimensional unit sphere in a one-dimensional and two-dimensional domain. It consists on the sum of a term that depends on the nearest and next-to-nearest interactions and a penalizing term that counts the spin's magnetic anisotropy transitions. We analyze the asymptotic behaviour of the energy, that is when the system is close to the helimagnet/ferromagnet transition point as the number of particles diverges. In the one-dimensional setting we compute the $\Gamma$-limit of renormalizations of the energy at first and second order. As a result, it is shown how much energy the system spends for any magnetic anistropy transition and chirality transition. In the two-dimensional setting, by computing the $\Gamma$-limit of the renormalization of the energy at second order, we we prove the emergence and study the geometric rigidity of chirality transitions

Crystallization of TiO2 nanotubes by in situ heating TEM

The thermally-induced crystallization of anodically grown TiO2 amorphous nanotubes has been studied so far under ambient pressure conditions by techniques such as differential scanning calorimetry and in situ X-ray diffraction, then looking at the overall response of several thousands of nanotubes in a carpet arrangement. Here we report a study of this phenomenon based on an in situ transmission electron microscopy approach that uses a twofold strategy. First, a group of some tens of TiO2 amorphous nanotubes was heated looking at their electron diffraction pattern change versus temperature, in order to determine both the initial temperature of crystallization and the corresponding crystalline phases. Second, the experiment was repeated on groups of few nanotubes, imaging their structural evolution in the direct space by spherical aberration-corrected high resolution transmission electron microscopy. These studies showed that, differently from what happens under ambient pressure conditions, under the microscope’s high vacuum (p < 10−5 Pa) the crystallization of TiO2 amorphous nanotubes starts from local small seeds of rutile and brookite, which then grow up with the increasing temperature. Besides, the crystallization started at different temperatures, namely 450 and 380 °C, when the in situ heating was performed irradiating the sample with electron beam energy of 120 or 300 keV, respectively. This difference is due to atomic knock-on effects induced by the electron beam with diverse energy

Mixed marker-based/marker-less visual odometry system for mobile robots

When moving in generic indoor environments, robotic platforms generally rely solely on information provided by onboard sensors to determine their position and orientation. However, the lack of absolute references often leads to the introduction of severe drifts in estimates computed, making autonomous operations really hard to accomplish. This paper proposes a solution to alleviate the impact of the above issues by combining two vision‐based pose estimation techniques working on relative and absolute coordinate systems, respectively. In particular, the unknown ground features in the images that are captured by the vertical camera of a mobile platform are processed by a vision‐based odometry algorithm, which is capable of estimating the relative frame‐to‐frame movements. Then, errors accumulated in the above step are corrected using artificial markers displaced at known positions in the environment. The markers are framed from time to time, which allows the robot to maintain the drifts bounded by additionally providing it with the navigation commands needed for autonomous flight. Accuracy and robustness of the designed technique are demonstrated using an off‐the‐shelf quadrotor via extensive experimental test

Current and emerging treatments for amyotrophic lateral sclerosis

Stefano Zoccolella1, Andrea Santamato2, Paolo Lamberti31Azienda Ospedaliero-UniversitariaOspedali Riuniti, Department of Medical and Neurological Sciences, Clinic of Nervous System Diseases, University of Foggia, Italy; 2Department of Physical Medicine and Rehabilitation, University of Foggia, OORR, Italy; 3Department of Neurology and Psychiatry, University of Bari, ItalyBackground: Amyotrophic lateral sclerosis (ALS) is a relatively rare neurodegenerative disorder of both upper and lower motoneurons. Currently, the management of ALS is essentially symptoms-based, and riluzole, an antiglutamatergic agent, is the only drug for the treatment of ALS approved by the food and drug administration.Objective: We reviewed current literature concerning emerging treatments for amyotrophic lateral sclerosis.Methods: A Medline literature search was performed to identify all studies on ALS treatment published from January 1st, 1986 through August 31st, 2009. We selected papers concerning only disease-modifying therapy.Results: Forty-eight compounds were identified and reviewed in this study.Conclusions: Riluzole is the only compound that demonstrated a beneficial effect on ALS patients, but with only modest increase in survival. Although several drugs showed effective results in the animal models for ALS, none of them significantly prolonged survival or improved quality of life of ALS patients. Several factors have been implicated in explaining the predominantly negative results of numerous randomized clinical trials in ALS, including methodological problems in the use of animal-drug screening, the lack of assessment of pharmacokinetic profile of the drugs, and methodological pitfalls of clinical trials in ALS patients.Keywords: amyotrophic lateral sclerosis, therapy, drug, surviva

Training Medical Communication Skills with Virtual Patients: Literature Review and Directions for Future Research

Effective communication is a crucial skill for healthcare providers since it leads to better patient health, satisfaction and avoids malpractice claims. In standard medical education, students’ communication skills are trained with role-playing and Standardized Patients (SPs), i.e., actors. However, SPs are difficult to standardize, and are very resource consuming. Virtual Patients (VPs) are interactive computer-based systems that represent a valuable alternative to SPs. VPs are capable of portraying patients in realistic clinical scenarios and engage learners in realistic conversations. Approaching medical communication skill training with VPs has been an active research area in the last ten years. As a result, the number of works in this field has grown significantly. The objective of this work is to survey the recent literature, assessing the state of the art of this technology with a specific focus on the instructional and technical design of VP simulations. After having classified and analysed the VPs selected for our research, we identified several areas that require further investigation, and we drafted practical recommendations for VP developers on design aspects that, based on our findings, are pivotal to create novel and effective VP simulations or improve existing ones

Single view vs. multiple views scatterplots

Among all the available visualization tools, the scatterplot has been deeply analyzed through the years and many researchers investigated how to improve this tool to face new challenges. The scatterplot visualization diagram is considered one of the most functional among the variety of data visual representations, due to its relative simplicity compared to other multivariable visualization techniques. Even so, one of the most significant and unsolved challenge in data visualization consists in effectively displaying datasets with many attributes or dimensions, such as multidimensional or multivariate ones. The focus of this research is to compare the single view and the multiple views visualization paradigms for displaying multivariable dataset using scatterplots. A multivariable scatterplot has been developed as a web application to provide the single view tool, whereas for the multiple views visualization, the ScatterDice web app has been slightly modified and adopted as a traditional, yet interactive, scatterplot matrix. Finally, a taxonomy of tasks for visualization tools has been chosen to define the use case and the tests to compare the two paradigms

Computer-assisted analysis of painting brushstrokes: digital image processing for unsupervised extraction of visible features from van Gogh's works

The automatic extraction of objective features from paintings, like brushstroke distribution, orientation, and shape, could be particularly useful for different artwork analyses and management tasks. In fact, these features contribute to provide a unique signature of the artists' style and can be effectively used for artist identification and classification, artwork examination and retrieval, etc. In this paper, an automatic technique for unsupervised extraction of individual brushstrokes from digital reproductions of van Gogh's paintings is presented. Through the iterative application of segmentation, characterization, and validation steps, valid brushstrokes complying with specific area and shape constraints are identified. On the extracted brushstrokes, several representative features can then be calculated, like orientation, length, and width. The accuracy of the devised method is evaluated by comparing numerical results obtained on a dataset of digital reproductions of van Gogh's oil-on-canvas works with observations made by human subjects and with another recent approach for automatic brushstroke analysis. Experimental tests showed that the devised methodology produces results that are rather close to those obtained by human subjects and, for some of the metrics considered, can provide improved performances with respect to alternative techniques

Hyperhomocysteinemia in L-dopa treated patients with Parkinson's disease: potential implications in cognitive dysfunction and dementia?

Abstract: Background: Hyperhomocysteinemia has been associated with cognitive dysfunction and dementia. The incidence of dementia in Parkinson’s Disease (PD) patients is higher than in the general population and plasma Homocysteine concentrations are increased in L-dopa treated PD patients. Objective: We evaluated the possible correlations between L-Dopa related hyperhomocysteinemia and cognitive dysfunction in PD. Methods: A Medline literature search was performed to identify all published studies on Homocysteine and cognitive dysfunction and dementia during the course of PD from 1966 to 31/03/2010. Results: Sixteen studies were found for review; ten studies focused on homocysteine and cognitive dysfunction in PD patients, five on homocysteine and PD dementia and two on homocysteine and markers of neurodegeneration in PD. The design of the study was retrospective in 14 studies, while 2 had a prospective design, with a variable follow-up period (from 24-weeks to 2 years). In most of the studies plasma homocysteine levels significantly correlated with cognitive functions, dementia and markers of neurodegeneration in PD patients. However, some studies did not confirm these findings. Several factors may concur to explain these partially conflicting results, including the retrospective design of the studies, their small sample size, their high percentage of excluded patients, and the use of a wide range of neuropsychological tasks in assessment of cognitive dysfunctions across the available studies. Conclusions: Available data seem to indicate a potential role of L-dopa related hyperhomocysteinemia on cognitive impairment and dementia during the course of PD