460 research outputs found
Angular momenta, helicity, and other properties of dielectric-fiber and metallic-wire modes
Spin and orbital angular momenta (AM) of light are well studied for
free-space electromagnetic fields, even nonparaxial. One of the important
applications of these concepts is the information transfer using AM modes,
often via optical fibers and other guiding systems. However, the
self-consistent description of the spin and orbital AM of light in optical
media (including dispersive and metallic cases) was provided only recently
[K.Y. Bliokh et al., Phys. Rev. Lett. 119, 073901 (2017)]. Here we present the
first accurate calculations, both analytical and numerical, of the spin and
orbital AM, as well as the helicity and other properties, for the full-vector
eigenmodes of cylindrical dielectric and metallic (nanowire) waveguides. We
find remarkable fundamental relations, such as the quantization of the
canonical total AM of cylindrical guided modes in the general nonparaxial case.
This quantization, as well as the noninteger values of the spin and orbital AM,
are determined by the generalized geometric and dynamical phases in the mode
fields. Moreover, we show that the spin AM of metallic-wire modes is
determined, in the geometrical-optics approximation, by the transverse spin of
surface plasmon-polaritons propagating along helical trajectories on the wire
surface. Our work provides a solid platform for future studies and applications
of the AM and helicity properties of guided optical and plasmonic waves.Comment: 12 pages, 4 figures, to appear in Optic
Weighted mixed weak-type inequalities for multilinear operators
In this paper we present a theorem that generalizes Sawyer's classic result about mixed weighted inequalities to the multilinear context. Let and , the main result of the paper sentences that under different conditions on the weights we can obtain
where is a multilinear Calder\'on-Zygmund operator. To obtain this result we first prove it for the -fold product of the Hardy-Littlewood maximal operator , and also for : the multi(sub)linear maximal function introduced in [LOPTT].
As an application we also prove a vector-valued extension to the mixed weighted weak-type inequalities of multilinear Calder\'on-Zygmund operators.Juan de la Cierva-Formaci\'on 2015 FJCI-2015-2454
Refusing to Endorse. A must Explanation for Pejoratives.
In her analysis of pejoratives, Eva Picardi rejects a too sharp separation between descriptive and expressive content. I reconstruct some of her arguments, endorsing Eva’s criticism of Williamson’s analysis of Dummett and developing a suggestion by Manuel Garcia Carpintero on a speech act analysis of pejoratives. Eva’s main concern is accounting for our instinctive refusal to endorse an assertion containing pejoratives because it suggests a picture of reality we do not share. Her stance might be further developed claiming that uses of pejoratives not only suggest, but also promote a wrong picture of reality. Our refusal to endorse implies rejecting not only a wrong picture of reality but also a call for participation to what that
picture promotes
The psychological burden of skin diseases: a cross-sectional multicenter study among dermatological out-patients in 13 European countries.
The contribution of psychological disorders to the burden of skin disease has been poorly explored, and this is a large-scale study to ascertain the association between depression, anxiety, and suicidal ideation with various dermatological diagnoses. This international multicenter observational cross-sectional study was conducted in 13 European countries. In each dermatology clinic, 250 consecutive adult out-patients were recruited to complete a questionnaire, reporting socio-demographic information, negative life events, and suicidal ideation; depression and anxiety were assessed with the Hospital Anxiety and Depression Scale. A clinical examination was performed. A control group was recruited among hospital employees. There were 4,994 participants--3,635 patients and 1,359 controls. Clinical depression was present in 10.1% patients (controls 4.3%, odds ratio (OR) 2.40 (1.67-3.47)). Clinical anxiety was present in 17.2% (controls 11.1%, OR 2.18 (1.68-2.82)). Suicidal ideation was reported by 12.7% of all patients (controls 8.3%, OR 1.94 (1.33-2.82)). For individual diagnoses, only patients with psoriasis had significant association with suicidal ideation. The association with depression and anxiety was highest for patients with psoriasis, atopic dermatitis, hand eczema, and leg ulcers. These results identify a major additional burden of skin disease and have important clinical implications.Peer reviewedFinal Published versio
RNA editing signature during myeloid leukemia cell differentiation
Adenosine deaminases acting on RNA (ADARs) are key proteins for hematopoietic stem cell self-renewal and for survival of differentiating progenitor cells. However, their specific role in myeloid cell maturation has been poorly investigated. Here we show that ADAR1 is present at basal level in the primary myeloid leukemia cells obtained from patients at diagnosis as well as in myeloid U-937 and THP1 cell lines and its expression correlates with the editing levels. Upon phorbol-myristate acetate or Vitamin D3/granulocyte macrophage colony-stimulating factor (GM-CSF)-driven differentiation, both ADAR1 and ADAR2 enzymes are upregulated, with a concomitant global increase of A-to-I RNA editing. ADAR1 silencing caused an editing decrease at specific ADAR1 target genes, without, however, interfering with cell differentiation or with ADAR2 activity. Remarkably, ADAR2 is absent in the undifferentiated cell stage, due to its elimination through the ubiquitin–proteasome pathway, being strongly upregulated at the end of the differentiation process. Of note, peripheral blood monocytes display editing events at the selected targets similar to those found in differentiated cell lines. Taken together, the data indicate that ADAR enzymes play important and distinct roles in myeloid cells
Is plant mitochondrial RNA editing a source of phylogenetic incongruence? An answer from in silico and in vivo data sets
<p>Abstract</p> <p>Background</p> <p>In plant mitochondria, the post-transcriptional RNA editing process converts C to U at a number of specific sites of the mRNA sequence and usually restores phylogenetically conserved codons and the encoded amino acid residues. Sites undergoing RNA editing evolve at a higher rate than sites not modified by the process. As a result, editing sites strongly affect the evolution of plant mitochondrial genomes, representing an important source of sequence variability and potentially informative characters.</p> <p>To date no clear and convincing evidence has established whether or not editing sites really affect the topology of reconstructed phylogenetic trees. For this reason, we investigated here the effect of RNA editing on the tree building process of twenty different plant mitochondrial gene sequences and by means of computer simulations.</p> <p>Results</p> <p>Based on our simulation study we suggest that the editing ‘noise’ in tree topology inference is mainly manifested at the cDNA level. In particular, editing sites tend to confuse tree topologies when artificial genomic and cDNA sequences are generated shorter than 500 bp and with an editing percentage higher than 5.0%. Similar results have been also obtained with genuine plant mitochondrial genes. In this latter instance, indeed, the topology incongruence increases when the editing percentage goes up from about 3.0 to 14.0%. However, when the average gene length is higher than 1,000 bp (<it>rps3</it>, <it>matR</it> and <it>atp1</it>) no differences in the comparison between inferred genomic and cDNA topologies could be detected.</p> <p>Conclusions</p> <p>Our findings by the here reported <it>in silico</it> and <it>in vivo</it> computer simulation system seem to strongly suggest that editing sites contribute in the generation of misleading phylogenetic trees if the analyzed mitochondrial gene sequence is highly edited (higher than 3.0%) and reduced in length (shorter than 500 bp).</p> <p>In the current lack of direct experimental evidence the results presented here encourage, thus, the use of genomic mitochondrial rather than cDNA sequences for reconstructing phylogenetic events in land plants.</p
Novel STAT1 Alleles in Otherwise Healthy Patients with Mycobacterial Disease
The transcription factor signal transducer and activator of transcription-1 (STAT1) plays a key role in immunity against mycobacterial and viral infections. Here, we characterize three human STAT1 germline alleles from otherwise healthy patients with mycobacterial disease. The previously reported L706S, like the novel Q463H and E320Q alleles, are intrinsically deleterious for both interferon gamma (IFNG)–induced gamma-activating factor–mediated immunity and interferon alpha (IFNA)–induced interferon-stimulated genes factor 3–mediated immunity, as shown in STAT1-deficient cells transfected with the corresponding alleles. Their phenotypic effects are however mediated by different molecular mechanisms, L706S affecting STAT1 phosphorylation and Q463H and E320Q affecting STAT1 DNA-binding activity. Heterozygous patients display specifically impaired IFNG-induced gamma-activating factor–mediated immunity, resulting in susceptibility to mycobacteria. Indeed, IFNA-induced interferon-stimulated genes factor 3–mediated immunity is not affected, and these patients are not particularly susceptible to viral disease, unlike patients homozygous for other, equally deleterious STAT1 mutations recessive for both phenotypes. The three STAT1 alleles are therefore dominant for IFNG-mediated antimycobacterial immunity but recessive for IFNA-mediated antiviral immunity at the cellular and clinical levels. These STAT1 alleles define two forms of dominant STAT1 deficiency, depending on whether the mutations impair STAT1 phosphorylation or DNA binding
Are skin disorders related to work strain in hospital workers? A cross-sectional study
To evaluate whether occupational stress factors (high demands, low control, low social support, strain, and iso-strain) are associated with skin disorders in hospital workers and whether psychological problems, such as anxiety and depression, act as potential mechanisms through which occupational stress factors are associated with skin disorders
The Main Belt Comets and ice in the Solar System
We review the evidence for buried ice in the asteroid belt; specifically the questions around the so-called Main Belt Comets (MBCs). We summarise the evidence for water throughout the Solar System, and describe the various methods for detecting it, including remote sensing from ultraviolet to radio wavelengths. We review progress in the first decade of study of MBCs, including observations, modelling of ice survival, and discussion on their origins. We then look at which methods will likely be most effective for further progress, including the key challenge of direct detection of (escaping) water in these bodies
Radiation Tolerance of SiGe BiCMOS Monolithic Silicon Pixel Detectors without Internal Gain Layer
A monolithic silicon pixel prototype produced for the MONOLITH ERC Advanced
project was irradiated with 70 MeV protons up to a fluence of 1 x 10^16 1 MeV
n_eq/cm^2. The ASIC contains a matrix of hexagonal pixels with 100 {\mu}m
pitch, readout by low-noise and very fast SiGe HBT frontend electronics. Wafers
with 50 {\mu}m thick epilayer with a resistivity of 350 {\Omega}cm were used to
produce a fully depleted sensor. Laboratory tests conducted with a 90Sr source
show that the detector works satisfactorily after irradiation. The
signal-to-noise ratio is not seen to change up to fluence of 6 x 10^14 n_eq
/cm^2 . The signal time jitter was estimated as the ratio between the voltage
noise and the signal slope at threshold. At -35 {^\circ}C, sensor bias voltage
of 200 V and frontend power consumption of 0.9 W/cm^2, the time jitter of the
most-probable signal amplitude was estimated to be 21 ps for proton fluence up
to 6 x 10 n_eq/cm^2 and 57 ps at 1 x 10^16 n_eq/cm^2 . Increasing the sensor
bias to 250 V and the analog voltage of the preamplifier from 1.8 to 2.0 V
provides a time jitter of 40 ps at 1 x 10^16 n_eq/cm^2.Comment: Submitted to JINS
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