829 research outputs found

    An automated method for characterization of evoked single-trial local field potentials recorded from rat barrel cortex under mechanical whisker stimulation

    Get PDF
    Rodents explore their surroundings through whisking by localizing objects and detecting textures very precisely. During such tactile exploration, whisker deflection is first mechanically transduced by receptors and then information encoded throughout the somatosensory pathway ending in the somatosensory ‘barrel’ cortex. In the barrel cortex, tactile information from a single whisker is segregated and processed in a cortical column corresponding to the deflected whisker. Local Field Potentials (LFPs) generated by whisker deflection in the barrel cortex present typical signatures in terms of shape and amplitude that are related to the activation of the local neuronal populations. Therefore, rigorous analysis of such responses may reveal important features about the function of underlying neuronal microcircuits. In this context, software methods for characterizing single-trial LFPs are needed that are also suitable for online extraction of LFP features and for brain–machine interfacing applications. In this work, we present an automated and efficient method to analyze evoked LFP responses in the rat barrel cortex through automatic removal of stimulation artifacts, detection of single events and characterization of their relevant parameters. Evoked single-trial LFPs recorded under two different anesthetics are examined to demonstrate the feasibility, accuracy and applicability of the method

    The development of stochastic based transport models to predict the advection and diffusion of bed-load sediment

    Get PDF
    Many morphological and environmental problems in rivers are associated with the transport of sediment, in particular with the movement of material along the stream bed. The complex nature of turbulent flow and the variability inherent within granular beds, along with the mutual influence one plays on the other, can only be described using the concepts of probability. It follows that the intermittent motion of bed-load particles can be termed by random variables. The stochasticity of key variables has been recently identified as a source of diffusion, i.e. suggesting that a plume of bed-load grains tends to spread while moving in the main flow direction. In this study the application of a Lagrangian analysis to existing high-frequency measurements of moving natural gravel particles contained in a tracking database helped to identify and scale the diffusive regimes related to different stages of grains' motion. Lagrangian tracking data allowed for an in-depth, study of the stochasticity of the particle step length, i.e. the single longitudinal distance computed by a grain from the entrainment to the deposition. The information on the distributed step lengths is then incorporated into a modified version of the Exner mass balance equation which has been developed to model the experimental advective and diffusive transport observed in long duration flume experiments with graded bed deposits comprised of natural sand and crashed marble gravel that have been previously reported. The modelling results indicate that the relative size of bed roughness, together with the thickness of the mixing surficial layer of the bed, play a major role in dictating the pattern of behaviour of particle motion. As the time-dependent burial depth of grains influences the vertical mixing and therefore the downstream diffusion of particles, concentrating the research only on the surficial motion of particles appears restrictive. In order to attain an insight view of the bed and to overcome the previous experimental limitations in terms of the description of the particle step distribution, a non-intrusive technique has been implemented in an annular flume to track the time history of tracing grains subject to intermittent motion in a bed made of transparent glass beads. In the light of the new information on particle transport, a more general Exner-based model incorporates the idea that tracer particles arriving at position x at time t started their random hops r at many different times. Its application to the latest sediment tracer concentration data has proven to be promising in that convincing detailed descriptions of the observed advective and diffusive behaviour of bed-load transport were obtained

    Benthic ecosystem functioning of the western Clarion-Clipperton Zone, Pacific Ocean, and the West Antarctic Peninsula : a study to assess the effectiveness of Areas of Particular Environmental Interest (APEIs) in the context of deep-sea mining and the effects of climate change

    Get PDF
    The deep sea encompasses the largest ecosystem on Earth and remains largely unexplored. With plans for deep-sea mining and the increasing impacts of climate change on our oceans, there is a growing necessity to understand and safeguard deep-sea biodiversity and ecosystem functioning. The cycling of carbon (C) by deep-sea benthic communities is a key ecosystem function and pulse-chase experiments are aimed to measure this process I conducted pulse-chase experiments in situ at abyssal depths (4800-5300 m) in three no-mining areas, called Areas of Particular Environmental Interest (APEIs), in the Clarion-Clipperton Zone (CCZ) and in ex situ experiments using sediments collected from a bathyal (500-600 m) fjord, Andvord Bay, and the continental shelf of the West Antarctic Peninsula (WAP). My results underline the importance of organic C in driving ecosystem dynamics at the abyssal seafloor and support the notion that Antarctic fjords are hotspots of benthic biomass and ecosystem functions. The microbial community was shown to be a key player in the short term (1.5 d) cycling of C on the abyssal plain of the western equatorial Pacific Ocean, which is consistent with other published studies, while the macrofaunal community (>300 µm) dominated the initial (~1 d) degradation of phytodetritus in Andvord Bay. My study provides important information on benthic ecosystem functioning in the western CCZ, an area targeted for commercial-scale deep-sea mining, and the WAP, a region that is becoming increasingly impacted by climate change

    Benthic ecosystem functioning of the western Clarion-Clipperton Zone, Pacific Ocean, and the West Antarctic Peninsula : a study to assess the effectiveness of Areas of Particular Environmental Interest (APEIs) in the context of deep-sea mining and the effects of climate change

    Get PDF
    The deep sea encompasses the largest ecosystem on Earth and remains largely unexplored. With plans for deep-sea mining and the increasing impacts of climate change on our oceans, there is a growing necessity to understand and safeguard deep-sea biodiversity and ecosystem functioning. The cycling of carbon (C) by deep-sea benthic communities is a key ecosystem function and pulse-chase experiments are aimed to measure this process I conducted pulse-chase experiments in situ at abyssal depths (4800-5300 m) in three no-mining areas, called Areas of Particular Environmental Interest (APEIs), in the Clarion-Clipperton Zone (CCZ) and in ex situ experiments using sediments collected from a bathyal (500-600 m) fjord, Andvord Bay, and the continental shelf of the West Antarctic Peninsula (WAP). My results underline the importance of organic C in driving ecosystem dynamics at the abyssal seafloor and support the notion that Antarctic fjords are hotspots of benthic biomass and ecosystem functions. The microbial community was shown to be a key player in the short term (1.5 d) cycling of C on the abyssal plain of the western equatorial Pacific Ocean, which is consistent with other published studies, while the macrofaunal community (>300 µm) dominated the initial (~1 d) degradation of phytodetritus in Andvord Bay. My study provides important information on benthic ecosystem functioning in the western CCZ, an area targeted for commercial-scale deep-sea mining, and the WAP, a region that is becoming increasingly impacted by climate change

    Is old stuff back? A fatal case of ethyl chloride sniffing

    Get PDF
    Background: Ethyl chloride (EC) or chloroethane is a colourless halogenated hydrocarbon gas regularly employed as a topical anaesthetic spray for pain-related injuries and muscle spasm in athletes. However, EC became also popular as a street drug in the 1980s. Brief inhalations of EC vapour can result in dizziness, euphoria, confusion, incoordination, hallucinosis, impairment of short-term memory and narcosis. Inhalation of higher doses, usually employed to \u201cget high\u201d, may be related to severe depression of the central nervous system. Indeed, toxicity and deaths have been reported so far. Case presentation: A 40-year-old man was found unresponsive after EC inhalation. EC determination was performed by dynamic headspace gas chromatography coupled to mass spectrometry. EC was detected in the peripheral blood (0.156 g/L), central blood concentration (0.203 g/L) and the lung and brain (19 and 25 mg/kg). EC in the vitreous humour showed a sensitively lower respect to blood (0.018 vs 0.203 g/L). Conclusions: Considering the results of toxicological analyses of investigations on the death scene besides the absence of any signs of trauma, death was attributed to inhalation of ethyl chloride

    The Influence of Personality, Resilience, and Alexithymia on Mental Health During COVID-19 Pandemic.

    Get PDF
    Following the COVID-19 pandemic, many countries worldwide have put lockdowns in place to prevent the virus from spreading. Evidence shows that lockdown measures can affect mental health; it is, therefore, important to identify the psychological characteristics making individuals more vulnerable. The present study aimed, first, to identify, through a cluster analysis, the psychological attributes that characterize individuals with similar psychological responses to the COVID-19 home confinement; second, to investigate whether different psychological characteristics, such as personality traits, alexithymia, and resilience, specifically influence anxiety, stress, and depression, depending on the scope of the confinement. We analyzed data from 393 participants who completed an online survey on their experiences during two different phases of the Italian lockdown, characterized by more or less strict measures of confinement. Two clusters were identified which included participants reporting a better (+ER) and worse (-ER) emotional response to the lockdown, respectively. Individuals in the -ER group showed lower emotional stability, resilience, and higher alexithymia. Moreover, even if lifting part of the restrictions decreased psychological distress among all participants, a reduction in perceived stress was observed only among individuals with high resilience. Finally, personality traits, alexithymia, and resilience differently affected depression, anxiety, and stress. Our results suggest that different psychological interventions should be planned depending on the context: mental health professionals should focus on enhancing the individuals' coping strategies to alleviate stress in emergencies, while long-term intervention aiming at alleviating anxiety and depressive symptoms should focus on alexithymic tendencies and personality constructs

    Increased emotional eating during COVID-19 associated with lockdown, psychological and social distress

    Get PDF
    Due to the spread of COVID 2019, the Italian government imposed a lockdown on the national territory. Initially, citizens were required to stay at home and not to mix with others outside of their household (Phase 1); eventually, some of these restrictions were lifted (Phase 2). To investigate the impact of lockdown on emotional and binge eating, an online survey was conducted to compare measures of self-reported physical (BMI), psychological (Alexithymia), affective (anxiety, stress, and depression) and social (income, workload) state during Phase 1 and Phase 2. Data from 365 Italian residents showed that increased emotional eating was predicted by higher depression, anxiety, quality of personal relationships, and quality of life, while the increase of bingeing was predicted by higher stress. Moreover, we showed that higher alexithymia scores were associated by increased emotional eating and higher BMI scores were associated with both increased emotional eating and binge eating. Finally, we found that from Phase 1 to Phase 2 binge and emotional eating decreased. These data provide evidence of the negative effects of isolation and lockdown on emotional wellbeing, and, relatedly, on eating behaviour

    Is old stuff back? A fatal case of ethyl chloride sniffing

    Get PDF

    SURGERY IN PATIENTS WITH TESTICULAR MALIGNANT GERM CELL TUMORS: COMPLIANCE TO SURGICAL GUIDELINES AND RESULTS IN THE ITALIAN COOPERATIVE STUDY

    Get PDF
    Purpose: Surgery represents a main and often the only treatment in patients with testicular Malignant Germ Cell Tumors (MGCT). We analyzed the compliance to surgical guidelines and the results in a series of patients with testicular MGCT -/+ retroperitoneal node involvement, without distant metastases. Method: 42 patients, observed in 15 Centers were enrolled in the Italian Cooperative Study on MGCT (January2004–December2010). 14/42 were younger than 2 y. of age, 28/42 between 13–18 y. Treatment was delivered according to COG-Staging-System: St.I patients (complete excision with inguinal orchifunicolectomy+decrease of markers, +hemiscrotectomy if scrotal involvement) did not receive further treatment; St.II patients (scrotal involvement after hemiscrotectomy and/or retroperitoneal node (RPN) enlargement:2 cm) had RPN Dissection if residuals were suspected after PEBx3or4. Results: St.I: 26 patients. 3/26 had a scrotal approach due to suspected testicular torsion: 1/3 underwent hemiscrotectomy, 2 did not receive further therapy after decrease of alphaFP, due to patient’s or physician’s decision respectively. 3/26 were successfully treated for RPN relapse, occurred at 3,6,9 months after adequate surgery (2 adolescents, 1 infant). St.II: in 4 patients CTwas delivered due to slight enlargement of RPN (+persistent alphaFP in 1). St.III: 12 patients received CT and RPND (bilateral in 1). Histology was negative in 11/12. All patients are alive without disease, 39 in 1stCR, 3 in 2ndCR (f.u 9–86 m.:med.48). 1 St.1 patient suffered from postoperative scrotal hematoma. Among patients younger than 2 y, 10/14 had a pure YST, 12/14 had St.I disease; among those between 13–18 y, 27/28 had a mixed histology, 14/28 were St.II or St.III. In 3 adolescents a testicular prosthesis was positioned during primary operation. Conclusion: Outcome was excellent. Regional relapses, observed only in St.I patients, were cured. Surgical guidelines were followed in 40/42 cases. Scrotal approach did not worsen the outcome of patients who did not receive further treatment
    corecore