1,566 research outputs found
Single-atom single-photon coupling facilitated by atomic-ensemble dark-state mechanisms
We propose to couple single atomic qubits to photons incident on a cavity
containing an atomic ensemble of a different species that mediates the coupling
via Rydberg interactions. Subject to a classical field and the cavity field,
the ensemble forms a collective dark state which is resonant with the input
photon, while excitation of a qubit atom leads to a secondary "dark" state that
splits the cavity resonance. The two different dark state mechanisms yield zero
and reflection phase shifts and can be used to implement quantum gates
between atomic and optical qubits.Comment: Revised and published version, incorporating an appendix on the
calculation of photon reflection amplitude
SFADI: the Speckle-Free Angular Differential Imaging method
We present a new processing technique aimed at significantly improving the
angular differential imaging method (ADI) in the context of high-contrast
imaging of faint objects nearby bright stars in observations obtained with
extreme adaptive optics (EXAO) systems. This technique, named "SFADI" for
"Speckle-Free ADI", allows to improve the achievable contrast by means of
speckles identification and suppression. This is possible in very high cadence
data, which freeze the atmospheric evolution. Here we present simulations in
which synthetic planets are injected into a real millisecond frame rate
sequence, acquired at the LBT telescope at visible wavelength, and show that
this technique can deliver low and uniform background, allowing unambiguous
detection of contrast planets, from to mas separations,
under poor and highly variable seeing conditions ( to arcsec FWHM)
and in only min of acquisition. A comparison with a standard ADI approach
shows that the contrast limit is improved by a factor of . We extensively
discuss the SFADI dependence on the various parameters like speckle
identification threshold, frame integration time, and number of frames, as well
as its ability to provide high-contrast imaging for extended sources, and also
to work with fast acquisitions.Comment: Accepted for publication in Ap
Proline affects the size of the root meristematic zone in Arabidopsis
We reported previously that root elongation in Arabidopsis is promoted by exogenous proline, raising the possibility that this amino acid may modulate root growth. To evaluate this hypothesis we used a combination of genetic, pharmacological and molecular analyses, and showed that proline specifically affects root growth by modulating the size of the root meristem. The effects of proline on meristem size are parallel to, and independent from, hormonal pathways, and do not involve the expression of genes controlling cell differentiation at the transition zone. On the contrary, proline appears to control cell division in early stages of postembryonic root development, as shown by the expression of the G2/M-specific CYCLINB1;1 (CYCB1;1) gene. The overall data suggest that proline can modulate the size of root meristematic zone in Arabidopsis likely controlling cell division and, in turn, the ratio between cell division and cell differentiation
Proline synthesis in developing microspores is required for pollen development and fertility
Background: In many plants, the amino acid proline is strongly accumulated in pollen and disruption of proline synthesis caused abortion of microspore development in Arabidopsis. So far, it was unclear whether local biosynthesis or transport of proline determines the success of fertile pollen development.
Results: We analyzed the expression pattern of the proline biosynthetic genes PYRROLINE-5-CARBOXYLATE SYNTHETASE 1 & 2 (P5CS1 & 2) in Arabidopsis anthers and both isoforms were strongly expressed in developing microspores and pollen grains but only inconsistently in surrounding sporophytic tissues. We introduced in a p5cs1/p5cs1 p5cs2/P5CS2 mutant background an additional copy of P5CS2 under the control of the Cauliflower Mosaic Virus (CaMV) 35S promoter, the tapetum-specific LIPID TRANSFER PROTEIN 12 (Ltp12) promoter or the pollen-specific At5g17340 promoter to determine in which site proline biosynthesis can restore the fertility of proline-deficient microspores. The specificity of these promoters was confirmed by β-glucuronidase (GUS) analysis, and by direct proline measurement in pollen grains and stage-9/10 anthers. Expression of P5CS2 under control of the At5g17340 promoter fully rescued proline content and normal morphology and fertility of mutant pollen. In contrast, expression of P5CS2 driven by either the Ltp12 or CaMV35S promoter caused only partial restoration of pollen development with little effect on pollen fertility.
Conclusions: Overall, our results indicate that proline transport is not able to fulfill the demand of the cells of the male germ line. Pollen development and fertility depend on local proline biosynthesis during late stages of microspore development and in mature pollen grains
Endothelial Function in Pre-diabetes, Diabetes and Diabetic Cardiomyopathy: A Review
Diabetes mellitus worsens cardiovascular risk profile of affected individuals. Its worldwide increasing prevalence and its negative influences on vascular walls morphology and function are able to induce the expression of several morbidities which worsen the clinical conditions of the patients getting them running towards a reduced survival curve.
Although overt diabetes increases the mortality rate of individuals due to its pathogenesis, poor information are in literature about the role of pre-diabetes and family history of diabetes mellitus in the outcome of general population.
This emphasizes the importance of early detection of vascular impairment in subjects at risk of developing
diabetes. The identification of early stages of atherosclerotic diseases in diabetic persons is a fundamental step in the risk stratification protocols followed-up by physicians in order to have a complete overview about the clinical status of such individuals. Common carotid intima-media thickness, flow-mediated vasodilatation, pulse wave velocity are instrumental tools able to detect the early impairment in cardiovascular system and stratify cardiovascular risk of individuals.
The aim of this review is to get a general perspective on the complex relationship between cardiovascular
diseases onset, pre-diabetes and family history of diabetes. Furthermore, it points out the influence of diabetes on heart function till the expression of the so-called diabetic cardiomyopathy
Large-scale monitoring of coppice forest clearcuts by multitemporal very high resolution satellite imagery. A case study from central Italy
Reliable assessment of forest resource stock, productivity and harvesting is a commonly agreed objective of
environmental monitoring programs. Distinctively, the assessment of wood harvesting has become even more
relevant to evaluate the sustainability of forest management and to quantify forest carbon budget. This paper
presents the development and testing of procedures for assessing forest harvesting in coppice forests by very high
resolution (VHR) satellite imagery. The study area is located in central Italy over approximately 34,000 km2. A set
of SPOT5 HRG multispectral images was acquired for the study years (2002–2007). Official administrative
statistics of coppice clearcutswere also acquired.More than 9500 clearcuts weremapped and dated by on-screen
interpretation of the SPOT5 images. In a subset of the study area various methods for semi-automatic clearcut
mapping were tested by pixel- and object-oriented approaches. The following results are presented: (i) clearcut
map developed by visual interpretation of the SPOT5 images resulted in high thematic (overall accuracy of 0.99)
and geometric (rootmean square error of clearcut boundary delineation of 5.3 m) reliability; (ii) object-oriented
approach achieved significantly better accuracy than pixel-based methods for semi-automatic classification of
the coppice clearcuts; (iii) comparison between mapped clearcut area and official forest harvesting statistics
proved a significant underestimation by the latter (65% of the total mapped clearcut area). A sample-based
procedure exploiting VHR satellite imagery is finally proposed to correct the official statistics of coppice clearcuts.L'articolo è disponibile sul sito dell'editore www.sciencedirect.co
First Occurrence of Willhendersonite in the Lessini Mounts, Northern Italy
none2noWillhendersonite is a rare zeolite, with very few occurrences reported globally (Terni Province, Italy; the Eifel Region, Germany; Styria, Austria). Moreover, the data available from these sites are very limited and do not allow a detailed picture of this zeolite’s mineralogical and chemical characteristics. In this work, a new willhendersonite occurrence is reported from the Tertiary volcanic rocks of the Lessini Mounts, northern Italy. Morphology, mineralogy and chemical composition of selected crystals were studied by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-ray Diffraction (XRD), and electron probe microanalyser (EPMA). Willhendersonite occurs within basanitic rocks as isolated, colorless, transparent crystals with prismatic to flattened morphologies. Individual crystals often grow together to form small elongated clusters and trellis-like aggregates. The diffraction pattern exhibits 33 well-resolved diffraction peaks, all of which can be indexed to a triclinic cell with unit cell parameters a = 9.239(2) Å; b = 9.221(2) Å; and c = 9.496(2) Å, α = 92.324(2)◦, β = 92.677(2)◦, γ = 89.992◦ (Space Group P1). The chemical data point to significant variability from Ca-rich willhendersonite (K0.23Na0.03 )Σ=0,26Ca1.24 (Si3.06Al3,00Fe3+0.01)Σ=6,07 O12·5H2O) to Ca-K terms (K0.94Na0.01)Σ=0,95Ca0.99 (Si3.07Al2.93Fe3+0.00)Σ=6,00O12·5H2O). Willhendersonite from the Lessini Mounts highlights the existence of an isomorphous series between the Ca-pure crystals and Ca-K compositions, possibly extended up to a potassic end-member.openMattioli, Michele; Cenni, MarcoMattioli, Michele; Cenni, Marc
The still under-investigated role of cognitive deficits in PML diagnosis
Background: Despite cognitive deficits frequently represent the first clinical manifestations of Progressive Multifocal Leukoencephalopathy (PML) in Natalizumab-treated MS patients, the importance of cognitive deficits in PML diagnosis is still under-investigated. The aim of the current study is to investigate the cognitive deficits at PML diagnosis in a group of Italian patients with PML. Methods: Thirty-four PML patients were included in the study. The demographic and clinical data, the lesion load and localization, and the longitudinal clinical course was compared between patients with (n = 13) and without (n = 15) cognitive deficit upon PML suspicion (the remaining six patients were asymptomatic). Clinical presentation of cognitive symptoms was described in detail. Result: After symptoms detection, the time to diagnosis resulted to be shorter for patients presenting with cognitive than for patients with non cognitive onset (p = 0.03). Within patients with cognitive onset, six patients were presenting with language and/or reading difficulties (46.15%); five patients with memory difficulties (38.4%); three patients with apraxia (23.1%); two patients with disorientation (15.3%); two patients with neglect (15.3%); one patients with object agnosia (7.7%), one patient with perseveration (7.7%) and one patient with dementia (7.7%). Frontal lesions were less frequent (p = 0.03), whereas temporal lesions were slightly more frequent (p = 0.06) in patients with cognitive deficits. The longitudinal PML course seemed to be more severe in cognitive than in non cognitive patients (F = 2.73, p = 0.03), but differences disappeared (F = 1.24, p = 0.29) when balancing for the incidence of immune reconstitution syndrome and for other treatments for PML (steroids, plasma exchange (PLEX) and other therapies (Mefloquine, Mirtazapine, Maraviroc). Conclusion: Cognitive deficits at PML onset manifest with symptoms which are absolutely rare in MS. Their appearance in MS patients should strongly suggest PML. Clinicians should be sensitive to the importance of formal neuropsychological evaluation, with particular focus on executive function, which are not easily detected without a formal assessment
Patients with paediatric-onset multiple sclerosis are at higher risk of cognitive impairment in adulthood: an Italian collaborative study
Background: Patients with paediatric-onset multiple sclerosis (POMS) could be at an increased risk for cognitive impairment (CI), given the potential harmful effects of disease activity in neurodevelopment. However, there is scarce information on their long-term cognitive outcomes.
Objective: To compare the prevalence and profile of CI between adults with a history of POMS and those with classic, adult-onset multiple sclerosis (AOMS).
Methods: Cognitive performance was assessed through the Brief Repeatable Battery (BRB) and the Stroop Test in consecutive patients referred to six Italian MS centres. CI was defined as impairment in ⩾2 cognitive domains.
Results: In all, 119 patients with POMS and 712 with AOMS were included in this analysis. The prevalence of CI was 48.0% in AOMS, 44.5% in POMS; with similar neuropsychological profile between the two groups. However, when adjusting for current age, we found a significantly increased risk for CI (odds ratio (OR) = 1.71; p = 0.02) and for impairment in information processing speed (OR = 1.86; p < 0.01) in patients with POMS. A higher Expanded Disability Status Scale (EDSS) was also identified in POMS (p = 0.03) compared with AOMS patients.The author(s) disclosed receipt of the following financial support for the research, authorship and/or publication of this article: This study was in part financed through an FISM (Italian Federation of Multiple Sclerosis) research grant
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