435 research outputs found

    Virtual and rapid prototyping of an underactuated space end effector

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    A fast and reliable verification of an initial concept is an important need in the field of mechatronics. Usually, the steps for a successful design require multiple iterations involving a sequence of design phases-the initial one and several improvements-and the tests of the resulting prototypes, in a trial and error scheme. Now a day’s software and hardware tools allow for a faster approach, in which the iterations between design and prototyping are by far reduced, even to just one in favorable situation. This work presents the design, manufacturing and testing of a robotic end effector for space applications, realized through virtual prototyping, followed by rapid prototyping realization. The first process allows realizing a mathematical model of the robotic system that, once all the simulations confirm the effectiveness of the design, can be directly used for the rapid prototyping by means of 3D printing. The workflow and the results of the process are described in detail in this paper, showing the qualitative and quantitative evaluation of the performance of both the virtual end effector and the actual physical robotic hand

    Covariant fracton gauge theory with boundary

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    In this paper we study the consequences of the introduction of a flat boundary on a 4D covariant rank-2 gauge theory described by a linear combination of linearized gravity and covariant fracton theory. We show that this theory gives rise to a Maxwell-Chern-Simons-like theory of two rank-2 traceless symmetric tensor fields. This induced 3D theory can be physically traced back to the traceless scalar charge theory of fractons, where the Chern-Simons-like term plays the role of a matter contribution. By further imposing time reversal invariance on the boundary, the Chern-Simons-like term disappears. Importantly, on the boundary of our 4D gauge theory we find a generalized U(1) Ka\c{c}-Moody algebra and the induced 3D theory is characterized by the conservation of the dipole moment.Comment: 37 pages, to appear in Physical Review

    Does make-up make you feel smarter? The "lipstick effect" extended to academic achievement.

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    AbstractPrevious studies have shown that higher levels of self-esteem are associated with better academic performance. However, there is no evidence if make-up can indirectly influence academic achievement and cognition through self-esteem. In this study, we examined the possibility that make-up can affect academic performance by asking 186 female undergraduate students to take a simulated university examination. Participants were randomly assigned to three groups, which consisted of wearing make-up, listening to positive music, and face coloring. Results showed that female students who had put make-up on received higher grades compared to those who did not. In addition, these students outperformed students with positive mood only and students who were engaged in a control activity. These findings underline the necessity of adopting a multidimensional approach to learning and memory and attest to the importance of studying further the interaction between physical self-esteem and cosmetics in cognition

    The leaf transcriptome of fennel (Foeniculum vulgare Mill.) enables characterization of the t-anethole pathway and the discovery of microsatellites and single-nucleotide variants

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    Fennel is a plant species of both agronomic and pharmaceutical interest that is characterized by a shortage of genetic and molecular data. Taking advantage of NGS technology, we sequenced and annotated the first fennel leaf transcriptome using material from four different lines and two different bioinformatic approaches: de novo and genome-guided transcriptome assembly. A reference transcriptome for assembly was produced by combining these two approaches. Among the 79,263 transcripts obtained, 47,775 were annotated using BLASTX analysis performed against the NR protein database subset with 11,853 transcripts representing putative full-length CDS. Bioinformatic analyses revealed 1,011 transcripts encoding transcription factors, mainly from the BHLH, MYB-related, C2H2, MYB, and ERF families, and 6,411 EST-SSR regions. Single-nucleotide variants of SNPs and indels were identified among the 8 samples at a frequency of 0.5 and 0.04 variants per Kb, respectively. Finally, the assembled transcripts were screened to identify genes related to the biosynthesis of t-anethole, a compound well-known for its nutraceutical and medical properties. For each of the 11 genes encoding structural enzymes in the t-anethole biosynthetic pathway, we identified at least one transcript showing a significant match. Overall, our work represents a treasure trove of information exploitable both for marker-assisted breeding and for in-depth studies on thousands of genes, including those involved in t-anethole biosynthesis

    Sentinel-2 Data and Unmanned Aerial System Products to Support Crop and Bare Soil Monitoring: Methodology Based on a Statistical Comparison between Remote Sensing Data with Identical Spectral Bands

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    The growing need for sustainable management approaches of crops and bare soils requires measurements at a multiple scale (space and time) field system level, which have become increasingly accurate. In this context, proximal and satellite remote sensing data cooperation seems good practice for the present and future. The primary purpose of this work is the development of a sound protocol based on a statistical comparison between Copernicus Sentinel-2 MIS satellite data and a multispectral sensor mounted on an Unmanned Aerial Vehicle (UAV), featuring spectral deployment identical to Sentinel-2. The experimental dataset, based on simultaneously acquired proximal and Sentinel-2 data, concerns an agricultural field in Pisa (Tuscany), cultivated with corn. To understand how the two systems, comparable but quite different in terms of spatial resolution and atmosphere impacts, can effectively cooperate to create a value-added product, statistical tests were applied on bands and the derived Vegetation and Soil index. Overall, as expected, due to the mentioned impacts, the outcomes show a heterogeneous behavior with a difference between the coincident bands as well for the derived indices, modulated in the same manner by the phenological status (e.g., during the canopy developments) or by vegetation absence. Instead, similar behavior between two sensors occurred during the maturity phase of crop plants

    Asymmetric effects of graspable distractor disks on motor preparation of successive grasps: a behavioural and event-related potential (ERP) study

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    There is evidence that seeing a graspable object automatically elicits a preparatory motor process. However, it is unclear whether this implicit visuomotor process might influence the preparation of a successive grasp for a different object. We addressed the issue by implementing a combined behavioural and electrophysiological paradigm. Participants performed pantomimed grasps directed to small or large disks with either a two (pincer) or a five-finger (pentapod) grip, after the presentation of congruent (same size) or incongruent (different size) distractor disks. Preview reaction times (PRTs) and response-locked lateralized readi-ness potentials (R-LRPs) were recorded as online indices of motor preparation. Results re-vealed asymmetric effects of the distractors on PRTs and R-LRPs. For pincer grip disks, in-congruent distractors were associated with longer PRTs and a delayed R-LRP peak. For pentapod grip disks, conversely, incongruent distractors were associated with shorter PRTs and a delayed R-LRP onset. Supporting an interpretation of these effects as tapping into motor preparation, we did not observe modulations of stimulus-locked LRP’s (sensitive to sensory processing), or of the P300 component (related to reallocating attentional resources). These results challenge models (i.e., the “dorsal amnesia” hypothesis) which assume that visuomotor information presented before a grasp will not affect how we later perform that grasp

    Temperature profile of ex-vivo organs during radio frequency thermal ablation by fiber Bragg gratings.

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    We report on the integration of fiber optic sensors with commercial medical instrumentation for temperature monitoring during radio frequency ablation for tumor treatment. A suitable configuration with five fiber Bragg grating sensors bonded to a bipolar radio frequency (RF) probe has been developed to monitor the area under treatment. A series of experiments were conducted on ex-vivo animal kidney and liver and the results confirm that we were able to make a multipoint measurement and to develop a real-time temperature profile of the area, with a temperature resolution of 0.1°C and a spatial resolution of 5 mm during a series of different and consecutive RF discharges

    Psychological Factors and Consumer Behavior During the COVID-19 Pandemic

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    The COVID-19 pandemic is far more than a health crisis: it has unpredictably changed our whole way of life. As suggested by the analysis of economic data on sales, this dramatic scenario has also heavily impacted individuals’ spending levels. To better understand these changes, the present study focused on consumer behavior and its psychological antecedents. Previous studies found that crises differently affect people’s willingness to buy necessities products (i.e., utilitarian shopping) and non-necessities products (i.e., hedonic shopping). Therefore, in examining whether changes in spending levels were associated with changes in consumer behavior, we adopted a fine-grained approach disentangling between necessities and non-necessities. We administered an online survey to 3833 participants (age range 18–64) during the first peak period of the contagion in Italy. Consumer behavior toward necessities was predicted by anxiety and COVID-related fear, whereas consumer behavior toward non-necessities was predicted by depression. Furthermore, consumer behavior toward necessities and non-necessities was predicted by personality traits, perceived economic stability, and self-justifications for purchasing. The present study extended our understanding of consumer behavior changes during the COVID-19 pandemic. Results could be helpful to develop marketing strategies that consider psychological factors to meet actual consumers’ needs and feelings

    Detecting User’s Behavior Shift with Sensorized Shoes and Stigmergic Perceptrons

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    As populations become increasingly aged, health monitoring has gained increasing importance. Recent advances in engineering of sensing, processing and artificial learning, make the development of non-invasive systems able to observe changes over time possible. In this context, the Ki-Foot project aims at developing a sensorized shoe and a machine learning architecture based on computational stigmergy to detect small variations in subjects gait and to learn and detect users behaviour shift. This paper outlines the challenges in the field and summarizes the proposed approach. The machine learning architecture has been developed and publicly released after early experimentation, in order to foster its application on real environments

    Open Surgery for Sportsman's Hernia a Retrospective Study

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    Sportsman's hernia is a painful syndrome in the inguinal area occurring in patients who play sports at an amatorial or professional level. Pain arises during sport, and sometimes persists after activity, representing an obstacle to sport resumption. A laparoscopic/endoscopic approach is proposed by many authors for treatment of the inguinal wall defect. Aim of this study is to assess the open technique in terms of safety and effectiveness, in order to obtain the benefit of an open treatment in an outpatient management. From October 2017 to July 2019, 34 patients underwent surgery for groin pain syndrome. All cases exhibited a bulging of the inguinal posterior wall. 14 patients were treated with Lichtenstein technique with transversalis fascia plication and placement of a polypropylene mesh fixed with fibrin glue. In 20 cases, a polypropylene mesh was placed in the preperitoneal space. The procedure was performed in day surgery facilities. Early or late postoperative complications did not occur in both groups. All patients returned to sport, in 32 cases with complete pain relief, whereas 2 patients experienced mild residual pain. The average value of return to sport was 34.11 ± 8.44 days. The average value of return to play was 53.82 ± 11.69 days. With regard to postoperative pain, no substantial differences between the two techniques were detected, and good results in terms of the resumption of sport were ensured in both groups. Surgical treatment for sportsman's hernia should be considered only after the failure of conservative treatment. The open technique is safe and allows a rapid postoperative recovery
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