A Hybrid Approach for Trajectory Control Design

This work presents a methodology to design trajectory tracking feedback control laws, which embed non-parametric statistical models, such as Gaussian Processes (GPs). The aim is to minimize unmodeled dynamics such as undesired slippages. The proposed approach has the benefit of avoiding complex terramechanics analysis to directly estimate from data the robot dynamics on a wide class of trajectories. Experiments in both real and simulated environments prove that the proposed methodology is promising.Comment: 9 pages, 11 figure

Learning the dynamics of articulated tracked vehicles

In this work, we present a Bayesian non-parametric approach to model the motion control of ATVs. The motion control model is based on a Dirichlet Process-Gaussian Process (DP-GP) mixture model. The DP-GP mixture model provides a flexible representation of patterns of control manoeuvres along trajectories of different lengths and discretizations. The model also estimates the number of patterns, sufficient for modeling the dynamics of the ATV

Efficient Parallel Carrier Recovery for Ultrahigh Speed Coherent QAM Receivers with Application to Optical Channels

This work presents a new efficient parallel carrier recovery architecture suitable for ultrahigh speed intradyne coherent optical receivers (e.g., ≥100 Gb/s) with quadrature amplitude modulation (QAM). The proposed scheme combines a novel low-latency parallel digital phase locked loop (DPLL) with a feedforward carrier phase recovery (CPR) algorithm. The new low-latency parallel DPLL is designed to compensate not only carrier frequency offset but also frequency fluctuations such as those induced by mechanical vibrations or power supply noise. Such carrier frequency fluctuations must be compensated since they lead to higher phase error variance in traditional feedforward CPR techniques, significantly degrading the receiver performance. In order to enable a parallel-processing implementation in multigigabit per second receivers, a new approximation to the DPLL computation is introduced. The proposed technique reduces the latency within the feedback loop of the DPLL introduced by parallel processing, while at the same time it provides a bandwidth and capture range close to those achieved by a serial DPLL. Simulation results demonstrate that the effects caused by frequency deviations can be eliminated with the proposed low latency parallel carrier recovery architecture.Fil: Gianni, Pablo. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Electrónica. Laboratorio de Comunicaciones Digitales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ferster, Laura. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Electrónica. Laboratorio de Comunicaciones Digitales; ArgentinaFil: Corral Briones, Graciela. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Electrónica. Laboratorio de Comunicaciones Digitales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Hueda, Mario Rafael. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Departamento de Electrónica. Laboratorio de Comunicaciones Digitales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

A PROPOSAL FOR A VIRTUAL REALITY METHOD IN LANGUAGE LEARNING

The paper presents a new method for the use of extended reality (XR) technologies in education, particularly in language learning. The authors realized a prototype of XR environment for distance learning of French language, via the software Unreal Engine 4. It deploys two types of VR activities, with the aim to improve understanding of grammatical concepts and memorization of new words, respectively. The dimension of depth is embedded into the learning process, by exploiting the kinesthetic aspects of the immersive environment. Thus, the learner moves in space and manipulates specific virtual objects involved in the learning activity to complete the task. A qualitative assessment has been conducted with a limited number of target students and now is currently under a wider experimental validation. However, the article introduces also the theoretical aspects of the new method, paving the way for further development

Transfer of aflatoxin from feed to milk and curd in Sarda ewes with different milk production level

Aflatoxin B1 (AFB1) is a toxin produced by some strains of Aspergillus growing in feedstuffs. Dairy animals fed with diet containing AFB1 excrete aflatoxin M1 (AFM1) into the milk. The carry over ratio (AFM1 excreted in milk/ AFB1 ingested) has been found lower in sheep (Battacone et al., 2002a) than in cattle (Veldman et al., 1992). Being AFM1 linked to milk proteins, its concentration in curd is higher than in milk. The AFM1 concentration in milk resulted not influenced by milk production level in cattle, therefore the total amount of AFM1 excreted in milk and, consequently, the carry-over ratio increased with milk yield (Munksgaard et al., 1987; Veldman et al., 1992). A previous study carried out on isoproductive dairy ewes showed an increase of the AFM1 concentration both in milk and in curd as the amount of AFB1 ingested increased (Battacone et al., 2002b). Aim of the present work is to study the influence of AFB1 dose and milk production level on the transfer of AFB1 from feeds to milk and curd as AFM1 in dairy ewes

Comparison of conjugated linoleic acid (CLA) content in milk of ewes and goats with the same dietary regimen

Milk fat is an important source of potential anticarcinogens named conjugated linoleic acid (CLA). The c9, t11-CLA is the major isomer and it is produced by ruminal hydrogenation of linoleic acid that leads first to vaccenic (11t-18:1) and finally to stearic acid (18:0). An alternative CLA pathway is related to the action of the mammary Δ9-desaturase enzyme on 11t-18:1. Diet is considered the main factor that influence the CLA concentration in milk fat. Differences in CLA content of sheep (Antongiovanni et al., 2002) and goats milk (Nudda et al., 2002) have been hypothesized, but results are difficult to compare due to different experimental condition in which the trials are carried out. The aim of this work is to compare the composition of milk fatty acids and CLA content in goats and sheep maintained in the same environmental condition and dietary regimen

The significance of early warning in chronic myeloid leukemia

We have read with great interest the manuscript by Eskazan and colleagues entitled \u201cCritical appraisal of European LeukemiaNet (ELN) 2013 recommendations for the management of chronic myeloid leukemia: is it early for a warning?\u201d. After a revision of the relatively limited literature, the Authors conclude that there are still no solid data to suggest a switch of therapy in patients with warning signs and that long-term survival remains a highly significant endpoint in CML patients. While we generally agree with these thoughts, we would like to stress a couple of additional points on the issue of ELN 2013 \u2013 defined \u201cwarning\u201d. The ELN recommendations defines warning as less than partial cytogenetic response (PCyR) and/or BCR-ABL1 >10% (according to the International Scale \u2013 IS) at 3 months, less than complete cytogenetic response (CCyR) and/or BCR-ABL1 >1%IS at 6 months, and BCR-ABL1 >0.1% IS, i.e. no major molecular response (MMR) at 12 months. So, at the first two time-points, conventionally considered as \u201cearly\u201d, both cytogenetic and molecular status define response, while at 12 months only BCR-ABL1 level >0.1 to 1%IS identifies warning patients, as anything less than CCyR is regarded as a failure. Our group analyzed the outcome of 216 CML patients treated with front-line standard dose (400 mg/day) imatinib with discordant cytogenetic and molecular responses at 3 and 6 months. Patients with even a single warning sign at 3 months (i.e. no PCyR or BCR-ABL1 >10%IS) had a significantly lower chance to obtain a subsequent CCyR (37% compared to 85% in patients with concordant optimal cytogenetic and molecular responses) and worse failure-free survival (FFS) (39% vs 81% at 48 months). Similarly, a warning sign at 6 months identified patients less prone to attain a MMR at 12 months (17% vs 82% in concordantly optimal patients) and with worse FFS (62% vs 88%). In our experience, most discordant patients had a \u201cmolecular warning\u201d, as 15/17 discordant at 3 months were in PCyR or better but with BCR-ABL1 transcript >10%IS and at 6 months 20/25 discordant were in CCyR with BCR-ABL1 >1%IS. This finding is an indirect confirmation of the importance of a BCR-ABL1 transcript level <10%IS at 3 months (now defined \u201cearly molecular response\u201d, EMR) as a positive predictor of long-term outcome, as reported by different studies. Despite EMR is gaining ground as a factor for an early switch of therapy, as suggested by NCCN guidelines, some reports indicate, in line with ELN recommendations, to consider also the 6-month cytogenetic or molecular status to assess a two-point evaluation of response to TKI therapy. The MDACC group analyzed the outcome of 453 CML patients treated with different TKIs, finding that 19 out of 44 patients (43%) not achieving major (i.e. optimal) cytogenetic response (MCyR) at 3 months obtained this response at 6 months and had an outcome comparable to patients achieving an earlier MCyR [8]. A Canadian study reviewed 320 patients receiving imatinib therapy with 3 and 6 month BCR-ABL1 transcript levels available, reporting that patients not achieving an EMR at 3 months but with BCR-ABL1 transcript <1% at 6 months (n=18) had similar FFS, progression-free survival (PFS) and overall survival (OS) compared to patients in EMR (n=184). Taken together, these data suggest that cytogenetic and molecular response at 6 months can identify a subgroup with favorable outcome among patients \u201cwarning\u201d at 3 months. However, considering patients with cytogenetic and/or molecular warning at 3 months in our series (n=41), only 2 had a subsequent optimal cytogenetic and molecular response at 6 months (unpublished). Moreover, we found that the rates of warning responses at 3 and 6 months were higher in cases with b2a2 BCR-ABL1 transcript type compared to those with b3a2 variant (32% vs 24% at 3 months and 31% vs 12% at 6 months, respectively). If there is still debate on the practical significance of a warning at 3 or 6 months, even less consensus and significantly less data are about the meaning of a late (i.e. at 12 months) warning. Starting from their database of 483 patients treated with four different TKI strategies, colleagues at MDACC found no benefit, in term of survival, in patients achieving MMR while in CCyR, even if their landmark analysis was performed at 18 and 24 months, and not at the 12-months timepoint. A landmark analysis of PFS and OS on the bases of molecular response at 12 months of imatinib performed in 128 patients from our database did not find any difference between patients in MMR or not (personal data, unpublished). Concordantly, a Spanish group showed that, in 198 patients treated with standard-dose imatinib and in CCyR without MMR at 12 months, a switch to a second-generation TKI was associated with a higher probability of subsequently major and deep molecular response, but no advantage in terms of PFS and OS and higher rates of discontinuation for adverse events, compared to patients continuing imatinib. Hopefully, more information on the therapeutic approach to \u201cwarning\u201d patients will come from an upcoming study of the GIMEMA Working Party on CML study aimed to evaluate efficacy of nilotinib frontline versus imatinib followed by switch to nilotinib in the case of absence of ELN-defined optimal response at 3, 6 or 12 months

Impact of different drug classes on clinical severity of falls in an elderly population: Epidemiological survey in a trauma center

AbstractPurposeCertain classes of drugs have been associated with the risk of falls in elderly individuals. The aim of this study was to evaluate the impact of several classes of drugs on fall-related injuries in individuals aged 65 years or older.MethodsData on all the emergency department (ED) visits for trivial falls during the year 2013 were retrieved from the database of the Academic Hospital of Parma. The individual reports of the visits were analyzed to evaluate where and how the patient fell, the drugs currently taken, the type, and severity of injury.ResultsA total of 2533 visits for trivial falls in patients aged 65 years or older were analyzed. We found a significant positive correlation between age and total number of drugs (r = 0.063; p < 0.03), but no correlation between the number of ED visits for trivial falls and the number of drugs (r = 0.001; p < 0.984). Anticoagulants [odds ratio (OR), 1.59; 95% confidence interval (CI), 1.22–2.07], antiplatelets (OR, 1.41; 95% CI, 1.12–1.79), and narcotic analgesics (OR, 2.38; 95% CI, 1.23–4.62) were predictors of hospital admission. Antiplatelets (OR, 2.02; 95% CI, 1.56–2.62), anticoagulants (OR, 1.89; 95% CI, 1.141–2.55), antihypertensive (OR, 1.44; 95% CI, 1.08–1.93), and psychotropic drugs (OR, 1.93; 95% CI, 1.09–3.44) were predictors of traumatic brain injury. Other classes of drugs were not related to any of the considered outcomes.ConclusionsTo reduce the risk of falling in elderly patients, a major focus should be placed on optimization of antihypertensives, narcotic analgesics, and psychotropic drugs administration. The risk-to-benefit ratio of anticoagulants and antiplatelet drugs should be individually tailored, to minimize the risk of adverse outcome of falls

A multicenter study on reliability and validity of a new triage system: the Triage Emergency Method version 2

In Italy there are many triage guidelines and methods based on consensus. But, to our knowledge, there are few data on the reliability and predictive validity of triage systems adopted by Italian emergency departments. The Triage Emergency Method version 2 (TEM v2) is a new four-level in-hospital triage system. This paper presentes a before-and-after observational study performed using triage scenarios from June 2008 to September 2009 in 6 Italian emergency departments. Twelve nurses who received a 5-h training on TEM and a panel of experts on TEM assigned priority code to 66 scenarios. To test the inter-rater reliability among participants and the panel of experts (before and after the course), we used the weighted K statistic. We assessed the validity of TEM by calculating sensitivity, specificity and accuracy for predicting the reference standard's triage score. The TEM v2 showed good and very-good agreement among all 6 groups of nurses with a K range=0.61-1. Also, sensitivity, specificity and accuracy of nurses' triage rating for predicting the reference standard's triage code was good (accuracy range=78-90%). In this multicenter study, TEM v2 has a good inter-rater reliability for rating triage acuity among all groups of participating nurses, with a K value similar to the reference standard reliability (K=0.75). Thus, the Triage Emergency Method version 2 seems to be valid and accurate in predicting a reference standard rating

Continuous dependence on the constitutive functions for a class of problems describing fluid flow in porous media

Abstract. — In this paper we consider the PDE describing the fluid flow in a porous medium, focusing on the solution’s dependence upon the choice of the saturation curve and the hydraulic conductivity. Basically, we consider two different saturation curves (say y1 and y2) and two different hydraulic conductivities (K1 and K2) which are both ‘‘close’’ in the L2 loc-norm. Then we find estimates to prove a constitutive stability for the solutions of the corresponding problems with the same boundary and initial conditions