116 research outputs found
On the quantum probability flux through surfaces
We remark that the often ignored quantum probability current is fundamental
for a genuine understanding of scattering phenomena and, in particular, for the
statistics of the time and position of the first exit of a quantum particle
from a given region, which may be simply expressed in terms of the current.
This simple formula for these statistics does not appear as such in the
literature. It is proposed that the formula, which is very different from the
usual quantum mechanical measurement formulas, be verified experimentally. A
full understanding of the quantum current and the associated formula is
provided by Bohmian mechanics.Comment: 15 pages, 3 figures, revised and more detailed version, to be
published in Journal of Statistical Physics, August 9
Synchrotron x-ray μ-tomography to model the thermal radiative properties of an opaque ceramic coating at T: 1000 K
Synchrotron x-ray μ-tomography has been used to reconstruct the three-dimensional view of a rough surface extracted from a heterogeneous ceramic coating composed of Pr2NiO4+δ. Radiographs with a resolution of 0.7 μm have been recorded at T = 300, 600, and 900 K. The analysis of surface geometry makes use of the geometrical optic approximation up to T = 900 K possible. Subsequently, a large number of rays (105) are impinged onto the numerical surface, as revealed by x-ray tomography, to reproduce the normal emissivity of the coating. This normal emissivity was obtained beforehand by infrared emittance spectroscopy at T = 1000 K. Comparison of the two approaches suggests that the optical contribution of the coating micropores can be integrated into the ray tracing code. The effective medium approximation is used for this purpose. Finally, the applicability of this hybrid approach is discusse
Borderline personality in patients with poly-diagnoses treated for a Bipolar Disorder
Some patients with dysphoria, explosive behaviour, or suicidal ideation, may receive a diagnosis of, and treatment for Bipolar Disorder (BD) and, not infrequently. The coexistence of these two diagnoses has been explained in different ways. Some authors include the BPD in the bipolar spectrum; others are sceptical about the existence of real comorbidity, suggesting a misdiagnosis. This study aimed to assess the personality of this group of poly-diagnosed patients (PolyD) and hypothesised they had a pathological borderline organisation. Via the administration of the Schedler Westen Assessment Procedure (SWAP-200), we compared PolyD patients with those suffering from BPD or BD only. We performed two different MANCOVAs to test PolyD, BPD and BD patients' differences in PD-factors, Q-traits and age. The sample comprised 45 patients (Mean age=43.3, SD=15.7; Females 57.7%, N=26). BD patients (N=15) did not present any personality disorder, they had a higher functioning and Obsessive Q-traits, and a lower Histrionic PD-factor than both PolyD (N=20) and BPD (N=10) patients. Compared to PolyD patients, BD had inferior PD-Borderline, PD-Antisocial factor and Dependent-Masochistic Q-traits, but there were no other differences with BPD patients. PolyD did not differ from BPD patients in any of the PD-factors and Q-traits. Our results suggest that PolyD patients are different from BD patients and propose to consider the pathological borderline personality as a central core of their disease
Acute Colonic Diverticulitis: CT Findings, Classifications, and a Proposal of a Structured Reporting Template
Acute colonic diverticulitis (ACD) is the most common complication of diverticular disease and represents an abdominal emergency. It includes a variety of conditions, extending from localized diverticular inflammation to fecal peritonitis, hence the importance of an accurate diagnosis. Contrast-enhanced computed tomography (CE-CT) plays a pivotal role in the diagnosis due to its high sensitivity, specificity, accuracy, and interobserver agreement. In fact, CE-CT allows alternative diagnoses to be excluded, the inflamed diverticulum to be localized, and complications to be identified. Imaging findings have been reviewed, dividing them into bowel and extra-intestinal wall findings. Moreover, CE-CT allows staging of the disease; the most used classifications of ACD severity are Hinchey’s modified and WSES classifications. Differential diagnoses include colon carcinoma, epiploic appendagitis, ischemic colitis, appendicitis, infectious enterocolitis, and inflammatory bowel disease. We propose a structured reporting template to standardize the terminology and improve communication between specialists involved in patient care
Spontaneous Abdominal Wall Hematoma Treated with Percutaneous Transarterial Embolization: Diagnostic Findings, Procedural Outcome, and Efficacy—A Multicenter Study
Endovascular management of abdominal wall hematomas (AWHs) is now the primary treatment option in hemodynamically stable patients, and it is often preferred to surgical interventions. The purpose of this multicentric study was to assess the safety, technical, and clinical success of percutaneous transarterial embolization (PTAE) of spontaneous AWHs to evaluate the efficacy of blind or empiric embolization compared to targeted embolization and to compare the outcome of the endovascular treatment approach in patients affected by COVID-19 and non-COVID-19 patients. We retrospectively enrolled 112 patients with spontaneous AWHs who underwent PTAE, focusing on signs of bleeding at pre-procedural CTA and DSA. Patients were separated into two groups depending on whether a blind or targeted embolization approach was used. We also divided patients into COVID-19 and non-COVID-19 groups. The mean age of the study population was 68.6 ± 15.8 years. CTA and DSA revealed signs of active bleeding in 99 and 88 patients, respectively. In 21 patients, blind embolization was performed. The overall technical success rate was 99%. Clinical success was obtained in 96 patients (86%), while 16 (14%) re-bled within 96 h. One patient reported a major peri-procedural complication. The comparison between blind and targeted embolization approaches showed no statistically significant differences in the characteristics of groups and technical and clinical success rates. No significant differences were found in the procedural outcome between COVID-19 and non-COVID-19 groups. Our study confirmed that PTAE is effective for treating spontaneous AWHs, even in COVID-19 patients. It suggests that the efficacy and safety of blind embolization are comparable to targeted embolization
Can sleep and resting behaviours be used as indicators of welfare in shelter dogs (Canis lupusfamiliaris)?
Previous research on humans and animals suggests that the analysis of sleep patterns
may reliably inform us about welfare status, but little research of this kind has been carried
out for non-human animals in an applied context. This study explored the use of sleep and
resting behaviour as indicators of welfare by describing the activity patterns of dogs (Canis
lupus familiaris) housed in rescue shelters, and comparing their sleep patterns to other
behavioural and cognitive measures of welfare. Sleep and activity patterns were observed
over five non-consecutive days in a population of 15 dogs. Subsequently, the characteristics
of sleep and resting behaviour were described and the impact of activity on patterns of
sleep and resting behaviour analysed. Shelter dogs slept for 2.8% of the day, 14.3% less
than previously reported and experienced less sleep fragmentation at night (32 sleep
bouts). There were no statistically significant relationships between behaviours exhibited
during the day and sleep behaviour. A higher proportion of daytime resting behaviour was
significantly associated with a positive judgement bias, less repetitive behaviour and
increased time spent coded as ‘relaxed’ across days by shelter staff. These results suggest
that, in the context of a busy shelter environment, the ability to rest more during the day
could be a sign of improved welfare. Considering the non-linear relationship between sleep
and welfare in humans, the relationship between sleep and behavioural indicators of welfare,
including judgement bias, in shelter dogs may be more complex than this study could
detect
Internet of Things for Sustainability: Perspectives in Privacy, Cybersecurity, and Future Trends
In the sustainability IoT, the cybersecurity risks to things, sensors, and monitoring systems are distinct from the conventional networking systems in many aspects. The interaction of sustainability IoT with the physical world phenomena (e.g., weather, climate, water, and oceans) is mostly not found in the modern information technology systems. Accordingly, actuation, the ability of these devices to make changes in real world based on sensing and monitoring, requires special consideration in terms of privacy and security. Moreover, the energy efficiency, safety, power, performance requirements of these device distinguish them from conventional computers systems. In this chapter, the cybersecurity approaches towards sustainability IoT are discussed in detail. The sustainability IoT risk categorization, risk mitigation goals, and implementation aspects are analyzed. The openness paradox and data dichotomy between privacy and sharing is analyzed. Accordingly, the IoT technology and security standard developments activities are highlighted. The perspectives on opportunities and challenges in IoT for sustainability are given. Finally, the chapter concludes with a discussion of sustainability IoT cybersecurity case studies
Growth of nanostructures by cluster deposition : a review
This paper presents a comprehensive analysis of simple models useful to
analyze the growth of nanostructures obtained by cluster deposition. After
detailing the potential interest of nanostructures, I extensively study the
first stages of growth (the submonolayer regime) by kinetic Monte-Carlo
simulations. These simulations are performed in a wide variety of experimental
situations : complete condensation, growth with reevaporation, nucleation on
defects, total or null cluster-cluster coalescence... The main scope of the
paper is to help experimentalists analyzing their data to deduce which of those
processes are important and to quantify them. A software including all these
simulation programs is available at no cost on request to the author. I
carefully discuss experiments of growth from cluster beams and show how the
mobility of the clusters on the surface can be measured : surprisingly high
values are found. An important issue for future technological applications of
cluster deposition is the relation between the size of the incident clusters
and the size of the islands obtained on the substrate. An approximate formula
which gives the ratio of the two sizes as a function of the melting temperature
of the material deposited is given. Finally, I study the atomic mechanisms
which can explain the diffusion of the clusters on a substrate and the result
of their mutual interaction (simple juxtaposition, partial or total
coalescence...)Comment: To be published Rev Mod Phys, Oct 99, RevTeX, 37 figure
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