822 research outputs found
More on gapped Goldstones at finite density: More gapped Goldstones
It was recently argued that certain relativistic theories at finite density
can exhibit an unconventional spectrum of Goldstone excitations, with gapped
Goldstones whose gap is exactly calculable in terms of the symmetry algebra. We
confirm this result as well as previous ones concerning gapless Goldstones for
non-relativistic systems via a coset construction of the low-energy effective
field theory. Moreover, our analysis unveils additional gapped Goldstones,
naturally as light as the others, but this time with a model-dependent gap.
Their exact number cannot be inferred solely from the symmetry breaking pattern
either, but rather depends on the details of the symmetry breaking mechanism--a
statement that we explicitly verify with a number of examples. Along the way we
provide what we believe to be a particularly transparent interpretation of the
so-called inverse-Higgs constraints for spontaneously broken spacetime
symmetries.Comment: 50 pages. v2: Fixed several typos in equations. Minor modifications
to the counting rule. Acknowledgements and references added. Matches JHEP
versio
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Cataract and optic disk drusen in a patient with glycogenosis and di George syndrome: clinical and molecular report
Background
We report the ophthalmic findings of a patient with type Ia glycogen storage disease (GSD Ia), DiGeorge syndrome (DGS), cataract and optic nerve head drusen (ONHD).
Case presentation
A 26-year-old white woman, born at term by natural delivery presented with a post-natal diagnosis of GSD Ia. Genetic testing by array-comparative genomic hybridization (CGH) for DGS was required because of her low levels of serum calcium. The patient has been followed from birth, attending the day-hospital every six months at the San Paolo Hospital, Milan, outpatient clinic for metabolic diseases and previously at another eye center. During the last day-hospital visit, a complete eye examination showed ONHD and cataract in both eyes. Next Generation Sequencing (NGS) was subsequently done to check for any association between the eye problems and metabolic aspects.
Conclusions
This is the first description of ocular changes in a patient with GSD Ia and DGS. Mutations explaining GSD Ia and DGS were found but no specific causative mutation for cataract and ONHD. The metabolic etiology of her lens changes is known, whereas the pathogenesis of ONHD is not clear. Although the presence of cataract and ONHD could be a coincidence; the case reported could suggest that hypocalcemia due to DGS could be the common biochemical pathway
Static response and Love numbers of Schwarzschild black holes
We derive the quadratic action for the physical degrees of freedom of massless spin-0, spin-1, and spin-2 perturbations on a Schwarzschild-(A)dS background in arbitrary dimensions. We then use these results to compute the static response of asymptotically flat Schwarzschild black holes to external fields. Our analysis reproduces known facts about black hole Love numbers-in particular that they vanish for all types of perturbation in four spacetime dimensions-but also leads to new results. For instance, we find that neutral Schwarzschild black holes polarize in the presence of an electromagnetic background in any number of spacetime dimensions except four. Moreover, we calculate for the first time black hole Love numbers for vector-type gravitational perturbations in higher dimensions and find that they generically do not vanish. Along the way, we shed some light on an apparent discrepancy between previous results in the literature, and clarify some aspects of the matching between perturbative calculations of static response on a Schwarzschild background and the point-particle effective theory.</p
Usefulness of echocardiography in the prognostic evaluation of non-Q-wave myocardial infarction.
Patients with non-Q-wave myocardial infarction (MI) are a heterogeneous population with a wide range of coronary disease severity and extent of myocardial necrosis, showing, therefore, different electrocardiographic findings and different outcomes. To evaluate the role of echocardiography in the management of non-Q-wave MI patients, 192 consecutive patients without previous MI were studied (78 with ST segment elevation, 56 with ST depression and 58 without ST modifications). All patients underwent 2-dimensional echocardiography (16-segment model) within 24 hours of admission to the coronary care unit. Wall-motion abnormalities, wall-motion score index, ejection fraction, and end-diastolic and end-systolic volumes were evaluated. In 35 patients, death, reinfarction, recurrent angina, or severe heart failure occurred during the in-hospital phase, whereas the remaining 157 patients had a good outcome. Patients with a poor prognosis were older (68 +/- 6 vs 59 +/- 5 years, p 3 segments 0.28 and 0.86; wall-motion score index > 1.33 = 0.28 and 0.87; end-diastolic volume > 46 mL/m2 = 0.49 and 0.91; ST segment depression and wall-motion abnormalities in > 3 segments 0.60 and 0.88. These results underline the usefulness of echocardiography in the early risk stratification of non-Q-wave MI patients, together with electrocardiographic data. Patients with ST segment depression and more extensive wall-motion abnormalities are at higher risk and their management needs a more aggressive approach
Genetic pre-participation screening in selected athletes: a new tool for the prevention of sudden cardiac death?
Sudden cardiac death (SCD) of athletes is a
topical issue. “Borderline cardiac abnormalities”, which occur in
~2% of elite male athletes, may result in SCD, which may have
a genetic base. Genetic analysis may help identify pathological
cardiac abnormalities. We performed phenotype-guided
genetic analysis in athletes who, pre-participation, showed
ECG and/or echo “borderline” abnormalities, to discriminate
subjects at a greater risk of SCD.
Methods: We studied 24 elite athletes referred by the National
Federation of Olympic sports; and 25 subjects seeking eligibility
to practice agonistic sport referred by the Osservatorio
Epidemiologico della Medicina dello Sport della Regione
Campania. Inclusion criteria: a) ECG repolarization borderline
abnormalities; b) benign ventricular arrhythmias; c) left
ventricular wall thickness in the grey zone of physiology versus
pathology (max wall thickness 12-15 mm in females; 13-16 mm
in males). Based on the suspected phenotype, we screened
subjects for the LMNA gene, for 8 sarcomeric genes, 5
desmosomal genes, and cardiac calcium, sodium and
potassium channel disease genes.
Results: Genetic analysis was completed in 37/49 athletes, 22
competitive and 27 non-competitive athletes, showing
“borderline” clinical markers suggestive of hypertrophic
cardiomyopathy (HCM,n. 24), dilated cardiomyopathy (n. 4),
arrhythmogenic right ventricular dysplasia/cathecholaminergic
polymorphic ventricular tachycardia (ARVD/CPVT, n. 11), long
QT syndrome (LQTS, n. 4), sick sinus syndrome (SSS, n. 5),
Brugada syndrome (BrS, n. 1). We identifyed 11 mutations in
9 athletes (an ARVD athlete was compound heterozygote for
the PKP2 gene and an HCM athlete was double heterozygote
for the MYBPC3 and TNNT2 genes): 3 known mutations
related to LQTS, HCM and ARVD, respectively, and 8 novel
mutations, located in the SCN5A, RyR2, PKP2, MYBPC3 and
ACTC1 genes. The new mutations were absent in ~800 normal
chromosomes and were predicted “probably damaging” by in
silico analysis. Patch clamp analysis in channelopathies
indicated for some mutation abnormal biophysical behavior of
the corresponding mutant protein.
Conclusion: Genetic analysis may help distinguish between
physiology and pathology in athletes with clinically suspected
heart disease
Full-length TDP-43 and its C-terminal domain form filamentsin vitrohaving non-amyloid properties
Accumulation of ubiquitin-positive, tau- and α-synuclein-negative intracellular inclusions of TDP-43 in the central nervous system represents the major hallmark correlated to amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U). Such inclusions have variably been described as amorphous aggregates or more structured deposits having amyloid properties. Here we have purified full-length TDP-43 (FL TDP-43) and its C-terminal domain (Ct TDP-43) to investigate the morphological, structural and tinctorial features of aggregates formed in vitro by them at pH 7.4 and 37 °C. AFM images indicate that both protein variants show a tendency to form filaments. Moreover, we show that both FL TDP-43 and Ct TDP-43 filaments possess a largely disordered secondary structure, as ascertained by far-UV circular dichroism and Fourier transform infra-red spectroscopy, do not bind Congo red and induce a very weak increase of thioflavin T fluorescence, indicating the absence of a clear amyloid-like signature
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Beam energy spread in FERMI@elettra gun and linac induced by intrabeam scattering
Intrabeam scattering (IBS) of electrons in the pre-cathode area in the electron guns know in the literature as Boersh effect is responsible for a growth of the electron beam energy spread there. Albeit most visible within the electron gun where the electron beam density is large and the energy spread is small, the IBS acts all along the entire electron beam pass through the Linac. In this report we calculate the energy spread induced by IBS in the FERMI@elettra electron gun
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