52 research outputs found
Very improved KINematic gravimetry: a new approach to aerogravimetry
The regional gravity field modeling by means of classical remove-compute-restore procedures is nowadays widely used in different contexts: from geodetic applications for the regional gravimetric geoid determination to exploration geophysics applications to extrapolate gridded or sparse points values of gravity anomalies (Bouguer, free-air, isostatic, etc.), useful to understand and map geological structures in a specific region. However, the accuracies and resolutions required for such exploration activity, do not consent the exploitation of satellite only gravity field data but need the integration with observation acquired at lower altitude.
Thanks to the development, in the late eighties and early nineties, of Global Navigation Satellite Systems (GNSS) and the consequent availability of accurate navigational data, techniques such as airborne gravimetry, that can provide this complementary information, started to spread worldwide. This technique represents nowadays one of the most efficient techniques ideal to collect gravity observations close to the Earth’s surface, in a fast and cost-effective way. Airborne gravimetry is capable of providing gravity measurements also in challenging environments which can be difficult to access otherwise, such as mountainous areas, rain forests and polar regions.
However due to the relatively high acquisition velocity, the presence of atmospheric turbulence, aircraft vibration, instrumental drift, etc. airborne data are usually contaminated by a very high observation error. For this reason a proper procedure to filter the raw observations both in the low and high frequency should be applied to recover valuable information.
In this work a new methodology to process airborne gravity measurements, named Very Improved KINematic Gravimetry (VIKING) is presented.
The proposed procedure allows to pre-process the raw observations coming from both the GNSS receiver and the gravimeter, with the aim to optimally combine the derived accelerations to compute gravity disturbances. Furthermore it consents to process by means of a filtering and gridding procedure these latter raw gravity disturbances to predict the signal on other points (grids or sparse points).
In details, the pre-processing deals with the manipulation of data acquired from the on board gravimeter and GNSS receiver to correct biases and derive gravity accelerations; while the processing regards the procedure to filter and grid the gravity accelerations data to obtain gravity anomalies/disturbances maps.
The developed algorithms used to pre-process raw GNSS acquired data are basically obtained by manipulating the classical GNSS observation equation to derive a new expression sensitive to the receiver acceleration (which corresponds to the vehicle acceleration) but almost insensitive to its actual position, by means of the implementation of the variometric approach. Regarding the pre-processing of the gravimeter data, the two principal aims of the method are the computation of all the corrections to properly combine gravimeter observations with GNSS observations and the optimal sampling of the gravimeter data, characterized by a very high observation rate, in such a way to not have loss of valuable information in terms of gravity accelerations.
The proposed solution to filter and grid raw airborne observations is a remove-compute-restore like procedure, and consists in a combination of an along track Wiener filter and a classical Least Squares Collocation technique. Basically the proposed procedure is an adaptation to airborne gravimetry of the Space-Wise approach, developed by Politecnico di Milano, to process data coming from the ESA satellite mission GOCE. Among the main differences with respect to the satellite application of this approach there is the fact that, while in processing GOCE data the stochastic characteristics of the observation error can be considered a-priori well known, in airborne gravimetry, due to the complex environment in which the observations are acquired, these characteristics are unknown and should be retrieved from the dataset itself.
The presented VIKING methodology is suited for airborne data analysis in order to be able to quickly filter and grid gravity observations in an easy fast and accurate way. Some innovative theoretical aspects focusing in particular on the theoretical covariance modeling are presented too.
An important part of the whole research project regarded the implementation of a suitable software for airborne gravity data processing. It has been developed in parallel C language and is organized in a set of toolboxes, which can be run independently from all the other ones, or in sequence to perform the whole processing. In order to evaluate the goodness of the whole procedure and its performances, various numerical tests have been performed on a real aerogravimetric dataset. The different tests were mainly focused on the analysis of the optimal choice of some parameters involved in the computation and on the performances in terms of accuracy and computational times of the various modules. The final result of the whole VIKING procedure, once calibrated the different parameters accordingly to the numerical tests performed, shows a predicted signal with ac- curacies of about 1.3 mGal. The obtained result in term of accuracy is in line with the expectations derived from the specific survey characteristics
Lithospheric modeling in Iran and the Arabian Peninsula from gravity data including seismic tomographic data: first results.
In this presentation we want show our lithosphere density model of a Middle East area encompassing Iran and the Arabian Peninsula, realized through a Bayesian inversion applied to an optimized density model. The starting model used for the inversion was obtained converting seismic velocities interpolated from local and global tomographies and converted in densities using a simplified version of the Brocher’s relation for velocity-to-density conversion, recalculating new coefficients for the relation. This optimization was realized following a Least Squares method, inverting global gravity field data. The model was divided into five parts: water, sediment, crust, mantle, and a separate crustal layer was defined in the Red Sea zone. Specifically, the Moho depth was obtained using the vertical velocity gradient method as presented in Tadiello and Braitenberg (2021), except for the southeastern zone along the Red Sea suture, which had strong velocity anomalies at the surface, and we relied on those to model a faster intrusive body within the crust, while estimation of the density distribution in the mantle was obtained using Perple_X software. We present the final density model, resulting from the inversion, and discuss it in terms of intra-crustal densification and relation to surface magmatic outcrops, finding that correlations can be identified. These demonstrate the presence of deep-seated crustal density variations which relate to geological provinces identified from surface investigations. A further point to discuss is the rheological properties obtainable from the joint velocity and density model and the relation to the inhomogeneous distribution of seismicity
GTE. A new software for gravitational terrain effect computation: theory and performances
The computation of the vertical attraction due to the topographic masses, the so-called Terrain Correction, is a fundamental step in geodetic and geophysical applications: it is required in high-precision geoid estimation by means of the remove–restore technique and it is used to isolate the gravitational effect of anomalous masses in geophysical exploration. The increasing resolution of recently developed digital terrain models, the increasing number of observation points due to extensive use of airborne gravimetry in geophysical exploration and the increasing accuracy of gravity data represents nowadays major issues for the terrain correction computation. Classical methods such as prism or point masses approximations are indeed too slow while Fourier based techniques are usually too approximate for the required accuracy. In this work a new software, called Gravity Terrain Effects (GTE), developed to guarantee high accuracy and fast computation of terrain corrections is presented. GTE has been thought expressly for geophysical applications allowing the computation not only of the effect of topographic and bathymetric masses but also those due to sedimentary layers or to the Earth crust-mantle discontinuity (the so-called Moho). In the present contribution, after recalling the main classical algorithms for the computation of the terrain correction we summarize the basic theory of the software and its practical implementation. Some tests to prove its performances are also described showing GTE capability to compute high accurate terrain corrections in a very short time: results obtained for a real airborne survey with GTE ranges between few hours and few minutes, according to the GTE profile used, with differences with respect to both planar and spherical computations (performed by prism and tesseroid respectively) of the order of 0.02 mGal even when using fastest profiles
Peripheral nervous system involvement in SARS-CoV-2 infection: a review of the current pediatric literature
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified as the pathogen responsible for the pandemic health emergency declared by the World Health Organization in March 2020. During the first part of the pandemic, adults showed mild to severe respiratory symptoms. Children seemed initially exempt, both from acute and subsequent complications. Hyposmia or anosmia were promptly identified as the main symptoms of acute infection, so neurotropism of SARS-CoV-2 was immediately suspected. (1, 2). As the emergency progressed, post infectious neurological complications were described also in pediatric population (3). Cases of cranial neuropathy in connection with acute SARS-CoV-2 infection have been reported in pediatric patients, as an isolate post infectious complication or in the context of the multisystem inflammatory syndrome in children (MIS-C) (4–6). Neuroinflammation is thought to be caused by several mechanisms, among which immune/autoimmune reactions (7), but so far, no specific autoantibody has been identified. SARS-CoV-2 can enter the central nervous system (CNS) directly and/or infect it retrogradely, through the peripheral nervous system (PNS), after replicating peripherally; several factors regulate invasion and subsequent neuroinflammation. Indeed, direct/secondary entry and replication can activate CNS-resident immune cells that, together with peripheral leukocytes, induce an immune response and promote neuroinflammation. In addition, as we will discuss in the following review, many cases of peripheral neuropathy (cranial and non-cranial) have been reported during or after SARS-CoV-2 infection. However, some authors have pointed out that the increase of cranial roots and ganglia in neurological imaging is not always observed in children with cranial neuropathy. (8). Even if a variety of case reports were published, opinions about an increased incidence of such neurologic diseases, linked to SARS-CoV-2 infection, are still controversial (9–11). Facial nerve palsy, ocular movements abnormalities and vestibular alterations are among the most reported issues in pediatric population (3–5). Moreover, an increased screen exposure imposed by social distancing led to acute oculomotion’s disturbance in children, not primarily caused by neuritis (12, 13). The aim of this review is to suggest food for thought on the role of SARS-CoV-2 in neurological conditions, affecting the peripheral nervous system to optimize the management and care of pediatric patients
Kiwifruit’s allergy in children: what do we know?
Abstract: Kiwifruit allergy is an emerging pathological condition in both general and pediatric
populations with a wide range of symptoms linked to variable molecular patterns, justifying systemic
and cross-reactions with other allergens (i.e., latex, pollen, and fruit). Skin prick test (SPT), specific
serum IgE (Act d 1, Act d 2, Act d 5, Act d 8, and Act d 10) directed against five out of thirteen
molecular allergens described in the literature, and oral test challenge with kiwifruit are available
for defining diagnosis. The management is similar to that of other food allergies, mostly based on
an elimination diet. Although kiwi allergy has been on the rise in recent years, few studies have
evaluated the clinical characteristics and methods of investigating this form of allergy. Data collected
so far show severe allergic reaction to be more frequent in children compared to adults. Therefore,
the aim of this review is to collect the reported clinical features and the available association with
specific molecular patterns of recognition to better understand how to manage these patients and
improve daily clinical practice
Low grade endotoxemia and oxidative stress in offspring of patients with early myocardial infarction
Background and aims: Offspring of patients with early myocardial infarction are at higher cardiovascular risk, but the underlying physio-pathological mechanism is unclear. NADPH oxidase-type 2 (NOX-2) plays a pivotal role as mediator of oxidative stress and could be involved in activating platelets in these patients. Furthermore, altered intestinal permeability and serum lipopolysaccharide (LPS) could be a trigger to promote NOX-2 activation and platelet aggregation. This study aims to evaluate the behavior of low grade endotoxemia, oxidative stress and platelet activation in offspring of patients with early myocardial infarction. Methods: We enrolled, in a cross-sectional study, 46 offspring of patients with early myocardial infarction and 86 healthy subjects (HS). LPS levels and gut permeability (assessed by zonulin), oxidative stress (assessed by serum NOX-2-derived peptide (sNOX2-dp) release, hydrogen peroxide (H2O2) production and isoprostanes), serum nitric oxide (NO) bioavailability and platelet activation (by serum thromboxane B2 (TXB2) and soluble P-Selectin (sP-Selectin)) were analyzed. Results: Compared to HS, offspring of patients with early myocardial infarction had higher values of LPS, zonulin, serum isoprostanes, sNOX2-dp H2O2, TXB2, p-selectin and lower NO bioavailability. Logistic regression analysis showed that the variables associated with offspring of patients with early myocardial infarction were LPS, TXB2 and isoprostanes. The multiple linear regression analysis confirmed that serum NOX-2, isoprostanes, p-selectin and H2O2 levels were significantly associated to LPS. Furthermore, serum LPS, isoprostanes and TXB2 levels were significantly associated with sNOX-2-dp. Conclusions: Offspring of patients with early myocardial infarction have a low grade endotoxemia that could generate oxidative stress and platelet activation increasing their cardiovascular risk. Future studies are needed to understand the role of dysbiosis in this population
The bnt162b2 vaccine induces humoral and cellular immune memory to sars-cov-2 Wuhan strain and the Omicron variant in children 5 to 11 years of age
SARS-CoV-2 mRNA vaccines prevent severe COVID-19 by generating immune memory, comprising specific antibodies and memory B and T cells. Although children are at low risk of severe COVID-19, the spreading of highly transmissible variants has led to increasing in COVID-19 cases and hospitalizations also in the youngest, but vaccine coverage remains low. Immunogenicity to mRNA vaccines has not been extensively studied in children 5 to 11 years old. In particular, cellular immunity to the wild-type strain (Wuhan) and the cross-reactive response to the Omicron variant of concern has not been investigated. We assessed the humoral and cellular immune response to the SARS-CoV-2 BNT162b2 vaccine in 27 healthy children. We demonstrated that vaccination induced a potent humoral and cellular immune response in all vaccinees. By using spike-specific memory B cells as a measurable imprint of a previous infection, we found that 50% of the children had signs of a past, undiagnosed infection before vaccination. Children with pre-existent immune memory generated significantly increased levels of specific antibodies, and memory T and B cells, directed against not only the wild type virus but also the omicron variant
Impact of immunochemotherapy with R-bendamustine or R-CHOP for treatment naïve advanced-stage follicular lymphoma: A subset analysis of the FOLL12 trial by Fondazione Italiana Linfomi
: We conducted a post hoc analysis of the FOLL12 trial to determine the impact of different initial immunochemotherapy (ICT) regimens on patient outcomes. Patients were selected from the FOLL12 trial, which included adults with stage II-IV follicular lymphoma (FL) grade 1-3a and high tumor burden. Patients were randomized 1:1 to receive either standard ICT followed by rituximab maintenance (RM) or the same ICT followed by a response-adapted approach. ICT consisted of rituximab-bendamustine (RB) or rituximab, cyclophosphamide, doxorubicin, and prednisone (R-CHOP), per physician's decision. A total of 786 patients were included in this analysis, 341 of whom received RB and 445 R-CHOP. RB was more frequently prescribed to older subjects, females, patients without bulky disease, and those with grade 1-2 FL. After a median of 56 months of follow-up, R-CHOP and RB had similar progression-free survival (PFS) (Hazard Ratio for RB 1.11, 95% CI 0.87-1.42, p = 0.392). Standard RM was associated with improved PFS compared to response-adapted management both after R-CHOP and RB. Grade 3-4 hematologic adverse events were more frequent with R-CHOP during induction treatment and more frequent with RB during RM. Grade 3-4 infections were more frequent with RB. RB was also associated with a higher incidence of transformed FL. R-CHOP and RB showed similar activity and efficacy, but with different safety profiles and long-term events, suggesting that the treating physician should carefully select the most appropriate chemotherapy regimen for each patient based on patient's individual characteristics, choices, and risk profile
Case Report: Interindividual variability and possible role of heterozygous variants in a family with deficiency of adenosine deaminase 2: are all heterozygous born equals?
Deficiency of adenosine deaminase 2 (DADA2) is a rare systemic autoinflammatory disease, typically with autosomal recessive inheritance, usually caused by biallelic loss of function mutations in the ADA2 gene. The phenotypic spectrum is broad, generally including fever, early-onset vasculitis, stroke, and hematologic dysfunction. Heterozygous carriers may show related signs and symptoms, usually milder and at an older age. Here we describe the case of two relatives, the proband and his mother, bearing an ADA2 homozygous pathogenic variant, and a heterozygous son. The proband was a 17-year-old boy with intermittent fever, lymphadenopathies, and mild hypogammaglobulinemia. He also had sporadic episodes of aphthosis, livedo reticularis and abdominal pain. Hypogammaglobulinemia was documented when he was 10 years old, and symptoms appeared in his late adolescence. The mother demonstrated mild hypogammaglobulinemia, chronic pericarditis since she was 30 years old and two transient episodes of diplopia without lacunar lesions on MRI. ADA2 (NM_001282225.2) sequencing identified both mother and son as homozygous for the c.1358A>G, p.(Tyr453Cys) variant. ADA2 activity in the proband and the mother was 80-fold lower than in the controls. Clinical features in both patients improved on anti-tumor necrosis factor therapy. An older son was found to be heterozygous for the same mutation post-mortem. He died at the age of 12 years due to a clinical picture of fever, lymphadenitis, skin rash and hypogammaglobulinemia evolving toward fatal multiorgan failure. Biopsies of skin, lymph nodes, and bone marrow excluded lymphomas and vasculitis. Despite being suspected of symptomatic carrier, the contribution of an additional variant in compound heterozygosity, or further genetic could not be ruled out, due to poor quality of DNA samples available. In conclusion, this familiar case demonstrated the wide range of phenotypic variability in DADA2. The search for ADA2 mutations and the assessment of ADA2 activity should be considered also in patients with the association of hypogammaglobulinemia and inflammatory conditions, also with late presentation and in absence of vasculitis. Furthermore, the clinical picture of the deceased carrier suggests a possible contribution of heterozygous pathogenic variants to inflammation
Genetic bases of C7 deficiency: systematic review and report of a novel deletion determining functional hemizygosity
Primary complement system (C) deficiencies are rare but notably associated with an increased risk of infections, autoimmunity, or immune disorders. Patients with terminal pathway C-deficiency have a 1,000- to 10,000-fold-higher risk of Neisseria meningitidis infections and should be therefore promptly identified to minimize the likelihood of further infections and to favor vaccination. In this paper, we performed a systematic review about clinical and genetic patterns of C7 deficiency starting from the case of a ten-year old boy infected by Neisseria meningitidis B and with clinical presentation suggestive of reduced C activity. Functional assay via Wieslab ELISA Kit confirmed a reduction in total C activity of the classical (0.6% activity), lectin (0.2% activity) and alternative (0.1% activity) pathways. Western blot analysis revealed the absence of C7 in patient serum. Sanger sequencing of genomic DNA extracted from peripheral blood of the patient allowed the identification of two pathogenetic variants in the C7 gene: the already well-characterized missense mutation G379R and a novel heterozygous deletion of three nucleotides located at the 3’UTR (c.*99_*101delTCT). This mutation resulted in an instability of the mRNA; thus, only the allele containing the missense mutation was expressed, making the proband a functional hemizygote for the expression of the mutated C7 allele
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