479 research outputs found
Quantum Interference Phenomena Between Impurity States in d-wave Superconductors
We investigate the mutual influence of impurities in two-dimensional d-wave
superconductors involving self-consistent solutions of the Bogoliubov-de Gennes
equations. The local order parameter suppression, the local density of states
(LDOS) as well as the interference of impurity-induced structures are analyzed.
We employ an impurity position averaging scheme for the DOS that does not
neglect these interference effects, as the commonly used -matrix approaches
do.Comment: 4 eps figures, presented at SNS200
IDIOPATHIC PARTIAL EPILEPSY WITH AUDITORY FEATURES (IPEAF): A CLINICAL AND GENETIC STUDY OF 53 SPORADIC CASES
The purpose of our study was to describe the clinical characteristics of sporadic
(S) cases of partial epilepsy with auditory features (PEAF) and pinpoint
clinical, prognostic and genetic differences with respect to previously reported
familial (F) cases of autosomal dominant partial epilepsy with auditory features
(ADPEAF). We analysed 53 patients (24 females and 29 males) with PEAF diagnosed
according to the following criteria: partial epilepsy with auditory symptoms,
negative family history for epilepsy and absence of cerebral lesions on NMR
study. All patients underwent a full clinical, neuroradiological and
neurophysiological examination. Forty patients were screened for mutations in
LGI1/epitempin, which is involved in ADPEAF. Age at onset ranged from 6 to 39
years (average 19 years). Secondarily generalized seizures were the most common
type of seizures at onset (79%). Auditory auras occurred either in isolation
(53%) or associated with visual, psychic or aphasic symptoms. Low seizure
frequency at onset and good drug responsiveness were common, with 51% of patients
seizure-free. Seizures tended to recur after drug withdrawal. Clinically, no
major differences were found between S and F patients with respect to age at
onset, seizure frequency and response to therapy. Analysis of LGI1/epitempin
exons failed to disclose mutations. Our data support the existence of a peculiar
form of non-lesional temporal lobe epilepsy closely related to ADPEAF but without
a positive family history. This syndrome, here named IPEAF, has a benign course
in the majority of patients and could be diagnosed by the presence of auditory
aura. Although LGI1 mutations have been excluded, genetic factors may play an
aetiopathogenetic role in at least some of these S cases
Human Computation and Convergence
Humans are the most effective integrators and producers of information,
directly and through the use of information-processing inventions. As these
inventions become increasingly sophisticated, the substantive role of humans in
processing information will tend toward capabilities that derive from our most
complex cognitive processes, e.g., abstraction, creativity, and applied world
knowledge. Through the advancement of human computation - methods that leverage
the respective strengths of humans and machines in distributed
information-processing systems - formerly discrete processes will combine
synergistically into increasingly integrated and complex information processing
systems. These new, collective systems will exhibit an unprecedented degree of
predictive accuracy in modeling physical and techno-social processes, and may
ultimately coalesce into a single unified predictive organism, with the
capacity to address societies most wicked problems and achieve planetary
homeostasis.Comment: Pre-publication draft of chapter. 24 pages, 3 figures; added
references to page 1 and 3, and corrected typ
Collective Spin Fluctuation Mode and Raman Scattering in Superconducting Cuprates
Although the low frequency electronic Raman response in the superconducting
state of the cuprates can be largely understood in terms of a d-wave energy
gap, a long standing problem has been an explanation for the spectra observed
in the polarization orientations. We present calculations which
suggest that the peak position of the observed spectra is due to a
collective spin fluctuation mode.Comment: 4 pages, 5 eps figure
Whole-brain histogram and voxel-based analyses of apparent diffusion coefficient and magnetization transfer ratio in celiac disease, epilepsy, and cerebral calcifications syndrome
BACKGROUND AND PURPOSE: Diffusion and magnetization transfer (MT) techniques have been applied to the investigation with MR of epilepsy and have revealed changes in patients with or without abnormalities on MR imaging. We hypothesized that also in the coeliac disease (CD), epilepsy and cerebral calcifications (CEC) syndrome diffusion and MT techniques could reveal brain abnormalities undetected by MR imaging and tentatively correlated to epilepsy.
MATERIALS AND METHODS: Diffusion and MT weighted images were obtained in 10 patients with CEC, 8 patients with CD without epilepsy and 17 healthy volunteers. The whole brain apparent diffusion coefficient (ADC) and MT ratio (MTR) maps were analyzed with histograms and the Statistical Parametric Mapping 2 (SPM2) software. We employed the non-parametric Mann-Whitney U test to assess differences for ADC and MTR histogram metrics. Voxel by voxel comparison of the ADC and MTR maps was performed with 2 tails t-test corrected for multiple comparison.
RESULTS: A significantly higher whole brain ADC value as compared to healthy controls was observed in CEC (P = 0.006) and CD (P = 0.01) patients. SPM2 showed bilateral areas of significantly decreased MTR in the parietal and temporal subcortical white matter (WM) in the CEC patients.
CONCLUSION: Our study indicates that diffusion and MT techniques are also capable of revealing abnormalities undetected by MR imaging. In particular patients with CEC syndrome show an increase of the whole brain ADC histogram which is more pronounced than in patients with gluten intolerance. IN CEC patients, voxel-based analysis demonstrates a localized decrease of the MTR in the parieto-temporal subcortical WM
Risk of hospitalization and death for COVID-19 in persons with epilepsy over a 20-month period: The EpiLink Bologna cohort, Italy
Objective: Data on COVID-19 outcomes in persons with epilepsy (PWE) are scarce and inconclusive. We aimed to study the risk of hospitalization and death for COVID-19 in a large cohort of PWE from March 1, 2020 to October 31, 2021. Methods: The historical cohort design (EpiLink Bologna) compared adult PWE grouped into people with focal epilepsy (PFE), idiopathic generalized epilepsy (PIGE), and developmental and/or epileptic encephalopathy (PDEE), and a population cohort matched (ratio 1:10) for age, sex, residence, and comorbidity (assessed with the multisource comorbidity score), living in the local health trust of Bologna (approximately 800 000 residents). Clinical data were linked to health administrative data. Results: In both cohorts (EpiLink: n = 1575 subjects, 1128 PFE, 267 PIGE, 148 PDEE, 32 other; controls: n = 15 326 subjects), 52% were females, and the mean age was 50 years (SD = 18). Hospital admissions for COVID-19 in the whole period were 49 (3.1%) in PWE and 225 (1.5%) in controls. The adjusted hazard ratio (aHR) in PWE was 1.9 (95% confidence interval [CI] = 1.4–2.7). The subgroups at higher risk were PFE (aHR = 1.9, 95% CI = 1.3–2.8) and PDEE (aHR = 3.9, 95% CI = 1.7–8.7), whereas PIGE had a risk comparable to the controls (aHR = 1.1, 95% CI =.3–3.5). Stratified analyses of the two main epidemic waves (March–May 2020, October 2020–May 2021) disclosed a higher risk of COVID-19-related hospitalization during the first epidemic wave (March–May 2020; aHR = 3.8, 95% CI = 2.2–6.7). Polytherapy with antiseizure medications contributed to a higher risk of hospital admission. Thirty-day risk of death after hospitalization was 14% in both PWE and controls. Significance: During the first 20 months since the outbreak of COVID-19 in Bologna, PWE had a doubled risk of COVID-19 hospital admission compared to a matched control population. Conversely, epilepsy did not represent a risk factor for COVID-19-related death
Anisotropic conductivity of Nd_{1.85}Ce_{0.15}CuO_{4-\delta} films at submillimeter wavelengths
The anisotropic conductivity of thin NdCeCuO
films was measured in the frequency range 8 cm 40 cm and
for temperatures 4 K K. A tilted sample geometry allowed to extract
both, in-plane and c-axis properties. The in-plane quasiparticle scattering
rate remains unchanged as the sample becomes superconducting. The temperature
dependence of the in-plane conductivity is reasonably well described using the
Born limit for a d-wave superconductor. Below T_{{\rm C}%} the c-axis
dielectric constant changes sign at the screened c-axis plasma
frequency. The temperature dependence of the c-axis conductivity closely
follows the linear in T behavior within the plane.Comment: 4 pages, 4 figure
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