2,310 research outputs found
Ideal observer analysis for continuous tracking experiments
Continuous tracking is a newly developed technique that allows fast and efficient data acquisition by asking participants to “track” a stimulus varying in some property (usually position in space). Tracking is a promising paradigm for the investigation of dynamic features of perception and could be particularly well suited for testing ecologically relevant situations difficult to study with classical psychophysical paradigms. The high rate of data collection may be useful in studies on clinical populations and children, who are unable to undergo long testing sessions. In this study, we designed tracking experiments with two novel stimulus features, numerosity and size, proving the feasibility of the technique outside standard object tracking. We went on to develop an ideal observer model that characterizes the results in terms of efficiency of conversion of stimulus strength into responses, and identification of early and late noise sources. Our ideal observer closely modeled results from human participants, providing a generalized framework for the interpretation of tracking data. The proposed model allows to use the tracking paradigm in various perceptual domains, and to study the divergence of human participants from ideal behavior
SiPM and front-end electronics development for Cherenkov light detection
The Italian Institute of Nuclear Physics (INFN) is involved in the
development of a demonstrator for a SiPM-based camera for the Cherenkov
Telescope Array (CTA) experiment, with a pixel size of 66 mm. The
camera houses about two thousands electronics channels and is both light and
compact. In this framework, a R&D program for the development of SiPMs suitable
for Cherenkov light detection (so called NUV SiPMs) is ongoing. Different
photosensors have been produced at Fondazione Bruno Kessler (FBK), with
different micro-cell dimensions and fill factors, in different geometrical
arrangements. At the same time, INFN is developing front-end electronics based
on the waveform sampling technique optimized for the new NUV SiPM. Measurements
on 11 mm, 33 mm, and 66 mm NUV SiPMs
coupled to the front-end electronics are presentedComment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherlands. All CTA contributions at
arXiv:1508.0589
Modeling brain connectivity dynamics in functional Magnetic Resonance Imaging via Particle Filtering
Interest in the studying of functional connections in the brain has grown considerably in the last decades, as many studies have pointed out that alterations in the interaction among brain areas can play a role as markers of neurological diseases. Most studies in this field treat the brain network as a system of connections stationary in time, but dynamic features of brain connectivity can provide useful information, both on physiology and pathological conditions of the brain. In this paper, we propose the application of a computational methodology, named Particle Filter (PF), to study non-stationarities in brain connectivity in functional Magnetic Resonance Imaging (fMRI). The PF algorithm estimates time-varying hidden parameters of a first-order linear time-varying Vector Autoregressive model (VAR) through a Sequential Monte Carlo strategy. On simulated time series, the PF approach effectively detected and enabled to follow time-varying hidden parameters and it captured causal relationships among signals. The method was also applied to real fMRI data, acquired in presence of periodic tactile or visual stimulations, in different sessions. On these data, the PF estimates were consistent with current knowledge on brain functioning. Most importantly, the approach enabled to detect statistically significant modulations in the cause-effect relationship between brain areas, which correlated with the underlying visual stimulation pattern presented during the acquisition
Cutaneous Melanomas: A Single Center Experience on the Usage of Immunohistochemistry Applied for the Diagnosis
Cutaneous melanoma (cM) is the deadliest of all primary skin cancers. Its prognosis is strongly influenced by the stage at diagnosis, with early stages having a good prognosis and being potentially treatable with surgery alone; advanced stages display a much worse prognosis, with a high rate of recurrence and metastasis. For this reason, the accurate and early diagnosis of cM is crucial—misdiagnosis may have extremely dangerous consequences for the patient and drastically reduce their chances of survival. Although the histological exam remains the “gold standard” for the diagnosis of cM, a continuously increasing number of immunohistochemical markers that could help in diagnosis, prognostic characterization, and appropriate therapeutical choices are identified every day, with some of them becoming part of routine practice. This review aims to discuss and summarize all the data related to the immunohistochemical analyses that are potentially useful for the diagnosis of cM, thus rendering it easier to appropriately applicate to routine practice. We will discuss these topics, as well as the role of these molecules in the biology of cM and potential impact on diagnosis and treatment, integrating the literature data with the experience of our surgical pathology department
Energy based vessel sealing devices in thyroid surgery: A systematic review to clarify the relationship with recurrent laryngeal nerve injuries
Background and objectives: The principal complications associated with thyroid surgery consist in postoperative recurrent laryngeal nerve (RLN) palsy, hypoparathyroidism, intra-operative and post-operative hemorrhage. In this paper, structured as a literature review, we describe the current knowledge and the technical improvements currently employed in the field of thyroid surgery, focusing on the contribution of energy based devices in relation with the reduction of the operating time and the odds of possible complication. Materials and methods: a relevant systematic literature search on Pubmed was carried out including works from 2004 through 2019, selecting studies providing information on the energy based devices employed in surgeries and statistic data concerning RNL (transient and permanent) injury and operative time. Results: Nineteen studies were reviewed, dealing with 4468 patients in total. The operative variables considered in this study are: employed device, number of patients, pathological conditions affecting the patients, surgical treatment, RNL injury percentage and the operating time, offering an insight on different patient conditions and their relative operative outcomes. A total of 1843 patients, accounting to the 41.2% of the total pool, underwent the traditional technique operation, while 2605 patients (58.3%) were treated employing the energy based devices techniques. Thyroidectomy performed by approaches different from traditional (for example robotic, MIVAT (Mini Invasive Video Assisted thyroidectomy)) were excluded from this study. Conclusions: The energy-based vessel sealing devices in study, represent a safe and efficient alternative to the traditional clamp-and-tie hand technique in the thyroidal surgery scenario, granting a reduction in operating time while not increasing RNL injury rates. According to this information, a preference for energy based devices techniques might be expressed, furthermore, a progressively higher usage rate for these devices is expected in the near future
Penetrating particle ANalyzer (PAN)
PAN is a scientific instrument suitable for deep space and interplanetary
missions. It can precisely measure and monitor the flux, composition, and
direction of highly penetrating particles (100 MeV/nucleon) in deep
space, over at least one full solar cycle (~11 years). The science program of
PAN is multi- and cross-disciplinary, covering cosmic ray physics, solar
physics, space weather and space travel. PAN will fill an observation gap of
galactic cosmic rays in the GeV region, and provide precise information of the
spectrum, composition and emission time of energetic particle originated from
the Sun. The precise measurement and monitoring of the energetic particles is
also a unique contribution to space weather studies. PAN will map the flux and
composition of penetrating particles, which cannot be shielded effectively,
precisely and continuously, providing valuable input for the assessment of the
related health risk, and for the development of an adequate mitigation
strategy. PAN has the potential to become a standard on-board instrument for
deep space human travel.
PAN is based on the proven detection principle of a magnetic spectrometer,
but with novel layout and detection concept. It will adopt advanced particle
detection technologies and industrial processes optimized for deep space
application. The device will require limited mass (~20 kg) and power (~20 W)
budget. Dipole magnet sectors built from high field permanent magnet Halbach
arrays, instrumented in a modular fashion with high resolution silicon strip
detectors, allow to reach an energy resolution better than 10\% for nuclei from
H to Fe at 1 GeV/n
Polynuclear Complexes: Two Amino-Phenol Macrocycles Spaced by Several Linear Polyamines; Synthesis, Binding Properties, and Crystal Structure
The synthesis and characterization of the new polytopic ligands 1,14-bis(3,6,9-triaza-15-hydroxybicyclo[9.3.1]pentadeca-11,13,115-trien-6-yl)-3,6,9,12-tetraazatetradecane L1, 1,15-bis(3,6,9-triaza-15-hydroxybicyclo[9.3.1]pentadeca-11,13,115-trien-6-yl)-3,6,10,13-tetraazapentadecane L2, and 1,16-bis(3,6,9-triaza-15-hydroxybicyclo[9.3.1]pentadeca-11,13,115-trien-6-yl)-3,7,10,14-tetraazahexadecane L3, containing two equal amino-phenol macrocycles spaced by several linear tetraamines, are reported. The basicity and coordination behavior toward the Cu(II) ion were potentiometrically determined in aqueous solution at 298.1 K. All the ligands show similar acid-base properties behaving as octaprotic bases in the examined pH range (pH = 2-12). The acid protons of L1-L3 cannot be removed under the experimental conditions used; thus, the main deprotonated species obtainable in aqueous solution are the neutral ligands, having amphionic character as demonstrated by UV-vis experiments. These species are able to form mono-, di-, and trinuclear Cu(II) complexes having stoichiometry [CuL]2+, [Cu2L]4+, and [Cu3L]6+, respectively, that can lose one or two protons giving rise to [CuH-1L]+, [Cu2H-2L]2+, and [Cu3H-2L]4+. Depending on the used ligand to metal molar ratio, the mono-, di-, or trinuclear species prevail over the others in solution. Both di- and trinuclear complexes are able to add secondary ligands (such as OH-), and in some cases two Cu(II) can cooperate to stabilize themby coordinating the guest in a bridged conformation. The structure of the [Cu2L3]4+ cation was resolved by X-ray analysis of the {[Cu2L3](ClO4)4 3 3H2O}2 3 H2O crystalline complex. It shows that each Cu(II) is penta-coordinated by one phenolate oxygen, two amine functions, belonging to one macrocyclic unit, and two amine functions of the spacer; in this species the distance between the two Cu(II) is about 5.3 Å
How emergency surgery has changed during the COVID-19 pandemic: A cohort study
Introduction: Various surgical societies constantly update their recommendations in order to adapt surgical activity on current Pandemic conditions. The aim of this study is to analyze how hospitalizations and emergency operations have changed in our Department of Medical and Surgical Sciences in the Hospital of Foggia during covid-19 pandemic. Methods: Our cohort-study was conducted by analyzing two groups of patients admitted to the Department of Medical and Surgical Sciences of the Hospital of Foggia: those admitted during the no-covid period from March 09th, 2019 to May 09th, 2019 and those during the covid period from March 09th, 2020 to May 09th, 2020. Results: A total of 750 patients admitted during the no-covid period of 2019 and 171 during the covid period of 2020, of these 222 were emergency admission during 2019 and 97 during 2020, 528 were elective admission during 2019 and 74 during 2020. Of the emergency admissions (222 during 2019 and 97 during 2020), 91 were operated during the no covid period in 2019 and 52 during the covid period in 2020. The mean Mannheim Peritonitis Index Score, that is a scoring system used in peritonitis which is simple and cost-effective, were 15.6 during the no covid period of 2019 and 22.2 during the covid period of 2020. We observed 29 post-operative complications during 2019 and 26 during 2020. Conclusions: Contraction of admissions for urgent and emergent conditions in the first period of lockdown has been followed from some positive effects as well as aggravating consequences
Multiphase modelling of tumour growth and extracellular matrix interaction: mathematical tools and applications
Resorting to a multiphase modelling framework, tumours are described here as a mixture of tumour and host cells within a porous structure constituted by a remodelling extracellular matrix (ECM), which is wet by a physiological extracellular fluid. The model presented in this article focuses mainly on the description of mechanical interactions of the growing tumour with the host tissue, their influence on tumour growth, and the attachment/detachment mechanisms between cells and ECM. Starting from some recent experimental evidences, we propose to describe the interaction forces involving the extracellular matrix via some concepts coming from viscoplasticity. We then apply the model to the description of the growth of tumour cords and the formation of fibrosis
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