1,540 research outputs found
Tunable plasmons in regular planar arrays of graphene nanoribbons with armchair and zigzag-shaped edges
Recent experimental evidence for and the theoretical confirmation of tunable edge plasmons and surface plasmons in graphene nanoribbons have opened up new opportunities to scrutinize the main geometric and conformation factors, which can be used to modulate these collective modes in the infrared-to-terahertz frequency band. Here, we show how the extrinsic plasmon structure of regular planar arrays of graphene nanoribbons, with perfectly symmetric edges, is influenced by the width, chirality and unit-cell length of each ribbon, as well as the in-plane vacuum distance between two contiguous ribbons. Our predictions, based on time-dependent density functional theory, in the random phase approximation, are expected to be of immediate help for measurements of plasmonic features in nanoscale architectures of nanoribbon devicesC.V.G. acknowledges the financial support of the “Secretaria Nacional de EducaciĂłn Superior, Ciencia, TecnologĂa e InnovaciĂłn” (SENESCYT-ECUADOR
Assessing the sensitivity of inflation to economic activity
A number of academic studies suggest that from the mid-1990s onwards there were changes in the link between inflation and economic activity. However, it remains unclear the extent to which this phenomenon can be ascribed to a change in the structural relationship between inflation and output, as opposed to a change in the size and nature of the shocks hitting the economy. This paper uses a suite of models, such as time-varying VAR techniques, traditional macro models, as well as DSGE models, to investigate, for various European countries as well as for the euro area, the evolution of the link between inflation and resource utilization and its dependence on the nature and size of the shocks. Our analysis suggests that the relationship between inflation and activity has indeed been changing over time, while remaining positive, with the correlation peaking during recessions. Quantitatively, the link between output and inflation is found to be highly dependent on which type of shocks hit the economy: while, in general, all demand shocks to output imply a reaction of inflation of the same sign, the latter will be less pronounced when output fluctuations are driven by supply shocks. In addition, a sharp deceleration of activity, as opposed to a subdued but protracted slowdown, results in a swifter decline in inflation. Inflation exhibits a rather strong persistence, with a negative impact still visible three years after the initial shock. JEL Classification: E31, E32, E37demand shock, inflation response, Macro model, output growth, Phillips curve
Microstructured Optical Fibers Filled with Carbon Nanotubes: Photonic Bandgap Modification and Sensing Applications
Evaluation of efficacy and safety of new high-density dyes for chromovitrectomy
The purpose of this study is to evaluate the safety and efficacy of two novel heavy dyes for macular surgery: DoubledyneTM and TwinTM. One eye from each of 144 patients undergoing surgery for macular hole or macular pucker was included in the study. The eyes were randomly divided into two groups according to the dye used during surgery. Best correct visual acuity (BCVA), intraocular pressure (IOP) and retinal morphology assessed by ocular coherence tomography (OCT) were evaluated before and 1, 3, 6 and 12 months after surgery. Only one surgeon performed each operation and provided a score ranging from 1 (poor) to 10 (excellent) for quality of staining and comfort in surgery. Statistical analysis was carried out with SPSS to compare parameters before and after surgery and between the two groups. No statistical differences were recorded in quality of staining (p = 0.11), in surgery comfort (p = 0.17) and total time of surgery (p = 0.44) between the two groups. BCVA statistically improved and central macular thickness (CMT) statistically decreased after surgery in both groups (p < 0.05). No toxic dye-related complications or long-term ones affecting the retina were observed in either group. According to this data, although confirmation in further studies with larger populations and longer follow up is required, DoubledyneTM and TwinTM proved to be safe and effective dyes for macular surgery
Matera, storytelling e cinema
I destini dei luoghi sono in relazione con le narrazioni, e Matera ne è un esempio. Negli anni Cinquanta, insieme al paradigma della vergogna, inizia a prendere forma un nuovo immaginario dei Sassi, la magia di un mondo contadino arcaico e sconosciuto. L’inversione del giudizio porta al riconoscimento del valore universale dei Sassi nel 1993, e al titolo di Capitale Europea della Cultura per il 2019. Molta cinematografia, fino alle più recenti esperienze immersive, ha contribuito a costruirne l’immagine e i progetti di futuro
Near field behavior of SnO 2 particle-layer deposited on standard optical fiber by electrostatic spray pyrolysis method
We report the emergent optical near field profiles from standard single mode optical fibers on the cleaved end of which were deposited particle layers of SnO(2). The layers, composed of micron and sub-micron sized particles, were deposited by means of Electrostatic Spray Pyrolysis (ESP) technique. Powerful analytical tools such as Atomic Force Microscopy (AFM) and Scanning Near-field Optical Microscopy (SNOM) were used to obtain simultaneously the SnO(2) layers topography and the related optical near field intensity distribution, when the fiber-substrate is illuminated by a light radiation in NIR range. We show that isolated microstructures, positioned in correspondence of the fiber core, reveal highly unusual capability of locally enhancing the collected optical near field. The observed phenomenon leads to new concepts of fiber optic chemical sensors and in fiber microsystems as well
Highlights of the Keystone Symposium: sirtuins in metabolism, aging and disease
From February 12–16, 2012, leading members of the sirtuin scientific community assembled in Tahoe, CA to attend the Keystone Symposium “Sirtuins in Aging, Metabolism, and Disease.” It was a vibrant and lively meeting, and in the spirit of Keystone Symposia, both established sirtuin researchers and those new to the field enjoyed a unique opportunity to interact and exchange ideas
Production and characterization of random electrode sectorization in GEM foils
In triple-GEM detectors, the segmentation of GEM foils in electrically
independent sectors allows reducing the probability of discharge damage to the
detector and improving the detector rate capability; however, a segmented foil
presents thin dead regions in the separation between two sectors and the
segmentation pattern has to be manually aligned with the GEM hole pattern
during the foil manufacturing, a procedure potentially sensitive to errors.
We describe the production and characterization of triple-GEM detectors
produced with an innovative GEM foil segmentation technique, the ``random hole
segmentation'', that allows an easier manufacturing of segmented GEM foils. The
electrical stability to high voltage and the gain uniformity of a random-hole
segmented triple-GEM prototype are measured. The results of a test beam on a
prototype assembled for the Phase-2 GEM upgrade of the CMS experiment are also
presented; a high-statistics efficiency measurement shows that the random hole
segmentation can limit the efficiency loss of the detector in the areas between
two sectors, making it a viable alternative to blank segmentation for the GEM
foil manufacturing of large-area detector systems
Undertreatment of breast cancer in the elderly
AIMS: The effect of undertreatment with adjuvant hormonal therapy, chemotherapy or radiation was studied in elderly women with breast cancer. METHODS: A prospectively maintained database was used to identify women undergoing potentially curative surgery between 1997 and 2011. The presentation, pathologic findings, treatment and outcomes of 449 women over 65 were compared to the findings in 1049 younger patients. Moreover, conventionally treated and undertreated elderly patients were identified and their characteristics and outcomes were compared. RESULTS: Both young and old patients presented most frequently with mammographic findings, but older patients presented more frequently with mammographic masses while younger patients presented more frequently with mammographic calcifications. Cancers of older patients were signicantly more favorable than cancers in younger patients with more infiltrating lobular, fewer ductal carcinoma in situ and more frequently estrogen receptor positive and fewer were poorly differentiated. Elderly patients had less axillary surgery, less adjuvant radiation therapy and more hormonal therapy. Fourty-six percent of the 449 elderly patients were undertreated by conventional criteria. Undertreated patients were more frequently in situ, better differentiated, smaller, and more often estrogen receptor positive. Forty-four percent of the undertreated patients died during follow-up without disease recurrence. CONCLUSIONS: Despite undertreatment, local and distant disease-free survival was comparable to patients who were not undertreated
Breast cancer surgery in elderly patients: postoperative complications and survival
AIMS AND BACKGROUND: Old age is associated with comorbidity and decreased functioning which influences treatment decisions in elderly breast cancer patients. The purpose of this study was to identify risk factors for complications after breast cancer surgery in elderly patients, and to assess mortality in patients with postoperative complications. METHODS: We retrospectively considered all female patients aged 65 years and older with invasive and in situ breast cancer who were diagnosed and treated between 1997 and 2012 in the Department of General and Geriatric Surgery of the University of Naples "Federico II". RESULTS AND CONCLUSION: 449 patients received surgery, of whom 18,2% (n = 82) developed one or more postoperative complications. The odds ratio of having postoperative complications show an increase with age, reaching statistical significance only for patients older than 85 [OR 5,75 (95% confidence interval 2,38-14,04); p < 0,001]. Number of concomitant diseases [OR 2,51 (95% CI 1,17 - 5,45); p = 0,01 for 3 or more concomitant diseases] and polypharmacy [OR 16,7 (95% CI 9,12 - 30,58); p < 0,0001) are associated to an increased risk of postoperative complications. Overall survival was worse in patients with postoperative complications [HR 2,06 (95% CI 1,52-2,70), p < 0,001]. This increased risk of mortality is probably due to geriatric parameters such as comorbidity or poor physical function, more than to higher complication rates
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