A Semantic Hierarchy for Erasure Policies

We consider the problem of logical data erasure, contrasting with physical erasure in the same way that end-to-end information flow control contrasts with access control. We present a semantic hierarchy for erasure policies, using a possibilistic knowledge-based semantics to define policy satisfaction such that there is an intuitively clear upper bound on what information an erasure policy permits to be retained. Our hierarchy allows a rich class of erasure policies to be expressed, taking account of the power of the attacker, how much information may be retained, and under what conditions it may be retained. While our main aim is to specify erasure policies, the semantic framework allows quite general information-flow policies to be formulated for a variety of semantic notions of secrecy.Comment: 18 pages, ICISS 201

Modification of Amorphous Mesoporous Zirconia Nanoparticles with Bisphosphonic Acids: A Straightforward Approach for Tailoring the Surface Properties of the Nanoparticles

The use of readily prepared bisphosphonic acids obtained in few steps through a thio-Michael addition of commercially available thiols on tetraethyl vinylidenebisphosphonate enables the straightforward surface modification of amorphous mesoporous zirconia nanoparticles. Simple stirring of the zirconia nanoparticles in a buffered aqueous solution of the proper bisphosphonic acid leads to the surface functionalization of the nanoparticles with different kinds of functional groups, charge and hydrophobic properties. Formation of both chemisorbed and physisorbed layers of the bisphosphonic acid take place, observing after extensive washing a grafting density of 1.1 molecules/nm2 with negligible release in neutral or acidic pH conditions, demonstrating stronger loading compared to monophosphonate derivatives. The modified nanoparticles were characterized by IR, XPS, ζ-potential analysis to investigate the loading of the bisphosphonic acid, FE-SEM to investigate the size and morphologies of the nanoparticles and 31P and 1H MAS NMR to investigate the coordination motif of the phosphonate units on the surface. All these analytical techniques demonstrated the strong affinity of the bisphosphonic moiety for the Zr(IV) metal centers. The functionalization with bisphosphonic acids represents a straightforward covalent approach for tailoring the superficial properties of zirconia nanoparticles, much straightforward compared the classic use of trisalkoxysilane or trichlorosilane reagents typically employed for the functionalization of silica and metal oxide nanoparticles. Extension of the use of bisphosphonates to other metal oxide nanoparticles is advisable

NEOWISE Observations of Near-Earth Objects: Preliminary Results

With the NEOWISE portion of the \emph{Wide-field Infrared Survey Explorer} (WISE) project, we have carried out a highly uniform survey of the near-Earth object (NEO) population at thermal infrared wavelengths ranging from 3 to 22 $\mu$m, allowing us to refine estimates of their numbers, sizes, and albedos. The NEOWISE survey detected NEOs the same way whether they were previously known or not, subject to the availability of ground-based follow-up observations, resulting in the discovery of more than 130 new NEOs. The survey's uniformity in sensitivity, observing cadence, and image quality have permitted extrapolation of the 428 near-Earth asteroids (NEAs) detected by NEOWISE during the fully cryogenic portion of the WISE mission to the larger population. We find that there are 981$\pm$19 NEAs larger than 1 km and 20,500$\pm$3000 NEAs larger than 100 m. We show that the Spaceguard goal of detecting 90% of all 1 km NEAs has been met, and that the cumulative size distribution is best represented by a broken power law with a slope of 1.32$\pm$0.14 below 1.5 km. This power law slope produces $\sim13,200\pm$1,900 NEAs with $D>$140 m. Although previous studies predict another break in the cumulative size distribution below $D\sim$50-100 m, resulting in an increase in the number of NEOs in this size range and smaller, we did not detect enough objects to comment on this increase. The overall number for the NEA population between 100-1000 m are lower than previous estimates. The numbers of near-Earth comets will be the subject of future work.Comment: Accepted to Ap

Chemical properties and protective effect of Rosmarinus officinalis: mitigation of lipid peroxidation and DNA-damage from arsenic exposure

Recent studies have implicated dietary factors in the cause and prevention of important diseases, with strong evidence that plant’s compounds can protect against these diseases. Moreover, food security and environmental contamination are topics in focus at the moment. In this view, contamination by arsenic (As) has received much attention as well as some spices with medicinal properties. Among these plants, the use of Rosmarinus officinalis L. has demonstrated antioxidant properties besides being used for circulatory disorders. Therefore, we measured the mitotic index of Allium cepa L. and characterized the antioxidant effects to determine the capacity of R. officinalis to ameliorate arsenic-induced DNA damage. R. officinalis extract showed no mutagenic effects and exhibited antimutagenic potential, reducing the DNA damage, anaphase-telophase briges and micronuclei chromosome aberrations that result from treatment with the arsenic. Additionally, reduction in arsenic- induced lipid peroxidation was also observed

A regulated deficit irrigation strategy for hedgerow olive orchards with high plant density

Background & Aims There is not a consensus on the best irrigation approach for super-high density (SHD) olive orchards. Our aim was to design and test a regulated deficit irrigation (RDI) strategy for a sustainable balance between water saving, tree vigour and oil production. Methods We tested our RDI strategy for 3 years in an ‘Arbequina’ orchard with 1,667 trees ha−1. Two levels of irrigation reduction were applied, 60RDI and 30RDI, scaled to replacing 60 % and 30 %, respectively, of the of irrigation needs (IN). We also had a full irrigation (FI) treatment as control, with IN totalling 4,701 m3 ha−1 Results The 30RDI treatment showed the best balance between water saving, tree vigour and oil production. With a yearly irrigation amount (IA) of 1,366 m3 ha−1, which meant 72 % water saving as compared to FI, the reduction in oil yield was 26 % only. Conclusions Our results, together with recent knowledge on the effect of water stress on fruit development, allowed us to suggest a potentially improved RDI strategy for which a total IA of ca. 2,100 m3 ha−1 was calculated. Both some management details and the benefits of this suggested RDI strategy are still to be tested

The Arabidopsis thaliana F-Box Protein FBL17 Is Essential for Progression through the Second Mitosis during Pollen Development

In fungi and metazoans, the SCF-type Ubiquitin protein ligases (E3s) play a critical role in cell cycle regulation by degrading negative regulators, such as cell cycle-dependent kinase inhibitors (CKIs) at the G1-to-S-phase checkpoint. Here we report that FBL17, an Arabidopsis thaliana F-box protein, is involved in cell cycle regulation during male gametogenesis. FBL17 expression is strongly enhanced in plants co-expressing E2Fa and DPa, transcription factors that promote S-phase entry. FBL17 loss-of-function mutants fail to undergo pollen mitosis II, which generates the two sperm cells in mature A. thaliana pollen. Nonetheless, the single sperm cell-like cell in fbl17 mutants is functional but will exclusively fertilize the egg cell of the female gametophyte, giving rise to an embryo that will later abort, most likely due to the lack of functional endosperm. Seed abortion can, however, be overcome by mutations in FIE, a component of the Polycomb group complex, overall resembling loss-of-function mutations in the A. thaliana cyclin-dependent kinase CDKA;1. Finally we identified ASK11, as an SKP1-like partner protein of FBL17 and discuss a possible mechanism how SCFFBL17 may regulate cell division during male gametogenesis

ANCA-associated vasculitis.

The anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAVs) are a group of disorders involving severe, systemic, small-vessel vasculitis and are characterized by the development of autoantibodies to the neutrophil proteins leukocyte proteinase 3 (PR3-ANCA) or myeloperoxidase (MPO-ANCA). The three AAV subgroups, namely granulomatosis with polyangiitis (GPA), microscopic polyangiitis and eosinophilic GPA (EGPA), are defined according to clinical features. However, genetic and other clinical findings suggest that these clinical syndromes may be better classified as PR3-positive AAV (PR3-AAV), MPO-positive AAV (MPO-AAV) and, for EGPA, by the presence or absence of ANCA (ANCA+ or ANCA-, respectively). Although any tissue can be involved in AAV, the upper and lower respiratory tract and kidneys are most commonly and severely affected. AAVs have a complex and unique pathogenesis, with evidence for a loss of tolerance to neutrophil proteins, which leads to ANCA-mediated neutrophil activation, recruitment and injury, with effector T cells also involved. Without therapy, prognosis is poor but treatments, typically immunosuppressants, have improved survival, albeit with considerable morbidity from glucocorticoids and other immunosuppressive medications. Current challenges include improving the measures of disease activity and risk of relapse, uncertainty about optimal therapy duration and a need for targeted therapies with fewer adverse effects. Meeting these challenges requires a more detailed knowledge of the fundamental biology of AAV as well as cooperative international research and clinical trials with meaningful input from patients

Viaggi e paesaggi di Guido Piovene

ISSN: 1828-866