5,511 research outputs found
Persistent Homology analysis of Phase Transitions
Persistent homology analysis, a recently developed computational method in
algebraic topology, is applied to the study of the phase transitions undergone
by the so-called XY-mean field model and by the phi^4 lattice model,
respectively. For both models the relationship between phase transitions and
the topological properties of certain submanifolds of configuration space are
exactly known. It turns out that these a-priori known facts are clearly
retrieved by persistent homology analysis of dynamically sampled submanifolds
of configuration space.Comment: 10 pages; 10 figure
Quantum effects in muon spin spectroscopy within the stochastic self-consistent harmonic approximation
In muon spin rotation experiments the positive implanted muon vibrates with
large zero point amplitude by virtue of its light mass. Quantum mechanical
calculations of the host material usually treat the muon as a point impurity,
ignoring this large vibrational amplitude. As a first order correction, the
muon zero point motion is usually described within the harmonic approximation,
despite the large anharmonicity of the crystal potential. Here we apply the
stochastic self-consistent harmonic approximation, a quantum variational method
devised to include strong anharmonic effects in total energy and vibrational
frequency calculations, in order to overcome these limitations and provide an
accurate ab initio description of the quantum nature of the muon. We applied
this full quantum treatment to the calculation of the muon contact hyperfine
field in textbook-case metallic systems, such as Fe, Ni, Co including MnSi and
MnGe, significantly improving agreement with experiments. Our results show that
muon vibrational frequencies are strongly renormalized by anharmonicity.
Finally, in contrast to the harmonic approximation, we show that including
quantum anharmonic fluctuations, the muon stabilizes at the octahedral site in
bcc Fe.Comment: 10 page
Unlocking the trust: the trasformative impact of blockchain technology on buyer seller relationship in business networks
Neostigmine-Induced Reversal of Faecal Impaction and Severe Constipation in a Young Patient with Systemic Sclerosis
No abstract availabl
Constraining Modified Gravity with Euclid
Future proposed satellite missions as Euclid can offer the opportunity to
test general relativity on cosmic scales through mapping of the galaxy weak
lensing signal. In this paper we forecast the ability of these experiments to
constrain modified gravity scenarios as those predicted by scalar-tensor and
theories. We found that Euclid will improve constraints expected from
the PLANCK satellite on these modified gravity models by two orders of
magnitude. We discuss parameter degeneracies and the possible biases introduced
by modified gravity
Beware the wrong way! A report on gastrografin inhalation
An 83-year-old man was admitted to the Emergency Department of St. Anna University Hospital, Cona, Italy, after he had inhaled diatrizoate (gastrografin), a well-known hyperosmolar contrast agent, during an X-ray of the upper gastrointestinal tract. The family physician recommended the patient to take the test in order to demonstrate a possible hiatal hernia. While swallowing gastrografin he had an esophageal spasm (detected at fluoroscopy), which led to the inhalation
of the contrast agent. After the episode, he was completely asymptomatic, eupnoeic, and with a good peripheral oxygen saturation. The physical examination was unremarkable. A chest X-ray of the lungs showed accumulation of the contrast agent in the distal bronchial tree (arrows in Figure 1A and B), with the right part being more involved because of the straight orientation of the right bronchus
Clinical characteristics and outcome of patients with autoimmune hemolytic anemia (AIHA) uniformly defined as primary by a diagnostic work-up
Primary autoimmune hemolytic anemia (P-AIHA) is a relatively uncommon and hetereogeneous disease characterized by the destruction of red blood cells due to anti-erythrocyte autoantibodies (AeAbs) in the absence of an associated disease [1–3].
Secondary AHIA is frequently associated with lymphoproliferative diseases (LD) in particular, chronic lymphocytic leukemia, aggressive or indolent lymphomas, autoimmune disorders, malignancies other than lymphoid, and infections [1,2,4].
On the hypothetical assumption that in a significant proportion of cases defined as P-AIHA the clinical heterogeneity could be due to an ignored associated disease, we retrospectively analyzed the clinical characteristics and outcome of patients with a diagnosis of P-AIHA based on a diagnostic work-up aimed at excluding or identifying an associated disease. ..
Buckling capacity model for timber screws loaded in compression: Experimental, analytical and FE investigations
This paper investigates the buckling of screws loaded in compression inserted into timber members. Screws are often used as a reinforcement in timber structures. However, under compression forces, they are prone to axial buckling. The current model for the screw buckling, enclosed in the EC5 proposal, is based on the general framework of EC3 for the instability of compressed steel members. The main shortcomings of the current formulation for the buckling of screws are the following. (1) The analytical expression for calculating the theoretical buckling load does not follow the observed modes. (2) Due to the need for dedicated studies, the value of the imperfection coefficient is arbitrarily chosen. This paper fills the above gaps. Firstly, a simple analytical expression for predicting the buckling of screws is proposed and validated against experimental and finite element (FE) findings. Furthermore, the formulation adopts a more accurate expression for lateral deformation based on experimental observation. Secondly, a FE model calibrated on experimental tests is used to estimate the defect coefficients of the instability curves as a function of the amplitude of the geometric defects of the screw, expressed as a fraction of its length. Finally, a Markov chain Monte Carlo analysis is carried out to simulate the capacity of screws with different sizes, assuming the uncertainty of all input parameters sampled from suitable probability distributions. The results are used to validate the proposed deterministic capacity model and estimate the uncertainty factors of the design equation
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