ALART: A novel lidar system for vegetation height retrieval from space

We propose a multi-kHz Single-Photon Counting (SPC) space LIDAR, exploiting low energy pulses with high repetition frequency (PRF). The high PRF allows one to overcome the low signal limitations, as many return shots can be collected from nearly the same scattering area. The ALART space instrument exhibits a multi-beam design, providing height retrieval over a wide area and terrain slope measurements. This novel technique, working with low SNRs, allows multiple beam generation with a single laser, limiting mass and power consumption. As the receiver has a certain probability to detect multiple photons from different levels of canopy, a histogram is constructed and used to retrieve the properties of the target tree, by means of a modal decomposition of the reconstructed waveform. A field demonstrator of the ALART space instrument is currently being developed by a European consortium led by cosine | measurement systems and funded by ESA under the TRP program. The demonstrator requirements have been derived to be representative of the target instrument and it will be tested in an equipped tower in woodland areas in the Netherlands. The employed detectors are state-of-the-art CMOS Single-Photon Avalanche Diode (SPAD) matrices with 1024 pixels. Each pixel is independently equipped with an integrated Time-to-Digital Converter (TDC), achieving a timing accuracy that is much lower than the SPAD dead time, resulting in a distance resolution in the centimeter range. The instrument emits nanosecond laser pulses with energy on the order of several J, at a PRF of ~ 10 kHz, and projects on ground a three-beams pattern. An extensive field measurement campaign will validate the employed technologies and algorithms for vegetation height retrieval

Photon-efficient imaging with a single-photon camera

Reconstructing a scene's 3D structure and reflectivity accurately with an active imaging system operating in low-light-level conditions has wide-ranging applications, spanning biological imaging to remote sensing. Here we propose and experimentally demonstrate a depth and reflectivity imaging system with a single-photon camera that generates high-quality images from ∼1 detected signal photon per pixel. Previous achievements of similar photon efficiency have been with conventional raster-scanning data collection using single-pixel photon counters capable of ∼10-ps time tagging. In contrast, our camera's detector array requires highly parallelized time-to-digital conversions with photon time-tagging accuracy limited to ∼ns. Thus, we develop an array-specific algorithm that converts coarsely time-binned photon detections to highly accurate scene depth and reflectivity by exploiting both the transverse smoothness and longitudinal sparsity of natural scenes. By overcoming the coarse time resolution of the array, our framework uniquely achieves high photon efficiency in a relatively short acquisition time

Breakaway oxidation su acciai inossidabili

In questo lavoro sono stati eseguiti trattamenti di ossidazione ad alta temperatura su un acciaio AISI 304L in condizioni controllate per studiare il fenomeno della breakaway oxidation. Esso consiste nella rottura localizzata dello strato di ossido dovuta a shock termici o meccanici, con conseguente esposizione di metallo non ossidato all’atmosfera ossidante. Data la sua natura, si tratta di un fenomeno difficile da prevedere e da monitorare. Sono stati messi a punto metodi per la sua identificazione attraverso tecniche di analisi termica e di microscopia elettronica. E’ stata valutata l’influenza di temperatura, atmosfera ossidante e umidità sulla occorrenza del fenomeno, con riferimento al processo produttivo degli acciai. La possibilità di prevedere nel dettaglio i tempi di trattamento termico ai quali si osserva il fenomeno di breakaway oxidation si conferma limitata

Sviluppo di microstrutture in campioni di argento sottoposti a deformazione plastica severa

Il lavoro presenta i risultati di indagini svolte su campioni di Ag commercialmente puro sottoposti adeformazione plastica severa mediante tecnica ECAP e attraverso laminazione asimmetrica a freddo. È statastudiata l’evoluzione della microstruttura e delle proprietà meccaniche al variare della deformazione impartita,rispettivamente mediante tecniche SEM / TEM e attraverso misure di durezza e prove di trazione. L’argentoè stato scelto come materiale rappresentativo dei metalli a struttura FCC con bassa energia dei difetti diimpilamento e quindi elevata possibilità di deformazione assistita da geminati. In letteratura esistono limitateinformazioni sull’evoluzione della struttura ultrafine di questi metalli nel regime di deformazione plasticasevera. I dati vengono discussi considerando l’evoluzione della struttura derivante dalle specifiche tecniche dideformazione e le proprietà raggiunte

Exposure to the Chinese Famine in Early Life and the Risk of Metabolic Syndrome in Adulthood

Objective: To examine whether exposure to the Chinese famine during fetal life and early childhood is associated with the risks of metabolic syndrome and whether this association is modified by later life environment. Research Design and Methods: We used data of 7,874 adults born between 1954 and 1964 from the 2002 China National Nutrition and Health Survey. Famine exposure groups were defined as nonexposed; fetal exposed; and early childhood, midchildhood, or late childhood exposed. Excess death rate was used to determine the severity of the famine. The ATP III criteria were used for the definition of metabolic syndrome (three or more of the following variables: elevated fasting triglyceride levels, lower HDL cholesterol levels, elevated fasting glucose levels, higher waist circumference, high blood pressure). Results: In severely affected famine areas, adults who were exposed to the famine during fetal life had a higher risk of metabolic syndrome, as compared with nonexposed subjects (odds ratio 3.13 [95% CI 1.24–7.89, P = 0.016]). Similar associations were observed among adults who were exposed to the famine during early childhood, but not for adults exposed to the famine during mid- or late childhood. Participants who were born in severely affected famine areas and had Western dietary habits in adulthood or were overweight in adulthood had a particularly high risk of metabolic syndrome in later life. Conclusions: Exposure to the Chinese famine during fetal life or infancy is associated with an increased risk of metabolic syndrome in adulthood. These associations are stronger among subjects with a Western dietary pattern or who were overweight in adulthood

Achieving a Molecular Remission before Allogeneic Stem Cell Transplantation in Adult Patients with Philadelphia Chromosome Positive Acute Lymphoblastic Leukemia: Impact on Relapse and Long Term Outcome

Allogeneic stem cell transplantation (alloHSCT) in first complete remission (CR1) remains the consolidation therapy of choice in Philadelphia-positive (Ph+) acute lymphoblastic leukemia (ALL). The prognostic value of measurable levels of minimal residual disease (MRD) at time of conditioning is a matter of debate. We analyzed the predictive relevance of MRD levels before transplantation on the clinical outcome of Ph+ ALL patients treated with chemotherapy and imatinib in 2 consecutive prospective clinical trials. MRD evaluation before transplantation was available for 65 of the 73 patients who underwent an alloHSCT in CR1. A complete or major molecular response at time of conditioning was achieved in 24 patients (37%), whereas 41 (63%) remained carriers of any other positive MRD level in the bone marrow. MRD negativity at time of conditioning was associated with a significant benefit in terms of risk of relapse at 5 years, with a relapse incidence of 8% compared with 39% for patients with MRD positivity (P\u2009=\u2009.007). However, thanks to the post-transplantation use of tyrosine kinase inhibitors (TKIs), disease-free survival was 58% versus 41% (P\u2009=\u2009.17) and overall survival was 58% versus 49% (P\u2009=\u2009.55) in MRD-negative compared with MRD-positive patients, respectively. The cumulative incidence of nonrelapse mortality was similar in the 2 groups. Achieving a complete molecular remission before transplantation reduces the risk of leukemia relapse even though TKIs may still rescue some patients relapsing after transplantation

D-dimer testing, with gender-specific cutoff levels, is of value to assess the individual risk of venous thromboembolic recurrence in non-elderly patients of both genders: a post hoc analysis of the DULCIS study

Male patients, especially the young, are at a higher risk of recurrent venous thromboembolism (RVTE) than females. Recent scientific reports show the use of D-dimer does not help predict RVTE risk in males. In the present report, we reviewed the data obtained in the DULCIS study (main report published in Blood 2014), focusing on D-dimer results recorded in non-elderly patients of both genders included in the study, and their relationship with RVTE events occurring during follow-up. Using specifically designed cutoff values for positive/negative interpretation, serial D-dimer measurements (performed during warfarin treatment and up to 3 months after discontinuation of anticoagulation) in 475 patients (males 57.3%) aged 64 65 years were obtained. D-dimer resulted positive in 46.3% and 30.5% of males and females, respectively (p = 0.001). Following management procedure, anticoagulation was stopped in 53.7% of males and 69.5% of females, who had persistently negative D-dimer results. The rate of subsequent recurrent events was 1.7% (95% CI 0.5\u20134.5%) and 0.4% (95% CI 0\u20132.5%) patient-years in males and females, respectively, with upper limits of confidence intervals always below the level of risk considered acceptable by international scientific societies for stopping anticoagulation (< 5%). In conclusion, using sensitive quantitative assays with specifically designed cutoff values and serial measurements during and after discontinuation of anticoagulation, D-dimer testing is useful to predict the risk of RVTE and is of help in deciding the duration of anticoagulation in both male and female adult patients aged up to 65 years