Myrmekite and strain weakening in granitoid mylonites

At mid-crustal conditions, deformation of feldspar is mainly accommodated by a combination of fracturing, dissolution\u2013precipitation, and reaction-weakening mechanisms. In particular, K-feldspar is reaction-weakened by the formation of strain-induced myrmekite \u2013 a \ufb01ne-grained symplectite of plagioclase and quartz. Here we use electron backscattered diffraction to (i) investigate the microstructure of a granodiorite mylonite, developed at 3c 450 \ub0C during cooling of the Rieserferner pluton (Eastern Alps); and (ii) assess the microstructural processes and the weakening associated with myrmekite development. Our analysis shows that the crystallographic orientation of plagioclase in pristine myrmekite was controlled by that of the replaced K- feldspar. Myrmekite nucleation resulted in both grain-size reduction and anti-clustered phase mixing by heterogeneous nucleation of quartz and plagioclase. The \ufb01ne grain size of sheared myrmekite promoted grain-size-sensitive creep mechanisms including \ufb02uid-assisted grain boundary sliding in plagioclase, coupled with heterogeneous nucleation of quartz within creep cavitation pores. Flow laws, calculated for monomineralic quartz, feldspar, and quartz + plagioclase aggregates (sheared myrmekite) during deformation at 450 \ub0C, show that grain-size-sensitive creep in sheared myrmekite accommodated strain rates several orders of magnitude higher than monomineralic quartz layers deforming by dislocation creep. Therefore, diffusion creep and grain size-sensitive processes contributed signi\ufb01cantly to bulk rock weakening during mylonitization. Our results have implications for modelling the rheology of the felsic middle crust

Empirical assessment of the effort needed to attack programs protected with client/server code splitting

Context. Code hardening is meant to fight malicious tampering with sensitive code executed on client hosts. Code splitting is a hardening technique that moves selected chunks of code from client to server. Although widely adopted, the effective benefits of code splitting are not fully understood and thoroughly assessed. Objective. The objective of this work is to compare non protected code vs. code splitting protected code, considering two levels of the chunk size parameter, in order to assess the effectiveness of the protection - in terms of both attack time and success rate - and to understand the attack strategy and process used to overcome the protection. Method. We conducted an experiment with master students performing attack tasks on a small application hardened with different levels of protection. Students carried out their task working at the source code level. Results. We observed a statistically significant effect of code splitting on the attack success rate that, on the average, was reduced from 89% with unprotected clear code to 52% with the most effective protection. The protection variant that moved some small-sized code chunks turned out to be more effective than the alternative moving fewer but larger chunks. Different strategies were identified yielding different success rates. Moreover, we discovered that successful attacks exhibited different process w.r.t. failed ones.Conclusions We found empirical evidence of the effect of code splitting, assessed the relative magnitude, and evaluated the influence of the chunk size parameter. Moreover, we extracted the process used to overcome such obfuscation technique

Factors affecting the Faradaic efficiency of Fe(0) electrocoagulation

Electrocoagulation (EC) using Fe(0) electrodes is a low cost water treatment technology that relies on efficient production of Fe(II) from the electrolytic dissolution of Fe(0) electrodes (i.e. a high Faradaic efficiency). However, the (electro)chemical factors that favor Fe(0) oxidation rather than O2 evolution during Fe(0) EC have not been identified. In this study, we combined electrochemical methods, electron microscopy and Fe measurements to systematically examine the interdependent effects of current density (i), anodic interface potential (EA) and solution chemistry on the Faradaic efficiency. We found that Fe(0) oxidation was favored (Faradaic efficiency >0.85) in chloride and bromide solutions at all i, whereas carbonate, phosphate, citrate, and nitrate solutions lead to Faradaic efficiencies <0.1. The anodic reaction (i.e. Fe(0) oxidation or O2 evolution) only depended on i in the sulfate and formate solutions. Experiments in binary-anion solutions revealed that molar ratios of [HCO3−]/[Cl−] near 100 and [NO3−]/[Cl−] near 20 separated the electrochemical domains of Fe(0) oxidation and O2 evolution in the EC system. These molar ratios were supported by experiments in synthetic groundwater solutions. We also found that the EA vs i curves for solutions with poor Faradaic efficiency overlapped but were situated 2–4 V vs Ag/AgCl higher than those of solutions with high Faradaic efficiency. Therefore, the position of the EA vs i curve, rather than the EA alone, can be used to determine unambiguously the reaction occurring on the Fe(0) anode during EC treatment

Does EO NDVI seasonal metrics capture variations in species composition and biomass due to grazing in semi-arid grassland savannas?

Most regional scale studies of vegetation in the Sahel have been based on Earth observation (EO) imagery due to the limited number of sites providing continuous and long term in situ meteorological and vegetation measurements. From a long time series of coarse resolution normalized difference vegetation index (NDVI) data a greening of the Sahel since the 1980s has been identified. However, it is poorly understood how commonly applied remote sensing techniques reflect the influence of extensive grazing (and changes in grazing pressure) on natural rangeland vegetation. This paper analyses the time series of Moderate Resolution Imaging Spectroradiometer (MODIS) NDVI metrics by comparing it with data from the Widou Thiengoly test site in northern Senegal. Field data include grazing intensity, end of season standing biomass (ESSB) and species composition from sizeable areas suitable for comparison with moderate – coarse resolution satellite imagery. It is shown that sampling plots excluded from grazing have a different species composition characterized by a longer growth cycle as compared to plots under controlled grazing or communal grazing. Also substantially higher ESSB is observed for grazing exclosures as compared to grazed areas, substantially exceeding the amount of biomass expected to be ingested by livestock for this area. The seasonal integrated NDVI (NDVI small integral; capturing only the signal inherent to the growing season recurrent vegetation), derived using absolute thresholds to estimate start and end of growing seasons, is identified as the metric most strongly related to ESSB for all grazing regimes. However plot-pixel comparisons demonstrate how the NDVI/ESSB relationship changes due to grazing-induced variation in annual plant species composition and the NDVI values for grazed plots are only slightly lower than the values observed for the ungrazed plots. Hence, average ESSB in ungrazed plots since 2000 was 0.93 t ha−1, compared to 0.51 t ha−1 for plots subjected to controlled grazing and 0.49 t ha−1 for communally grazed plots, but the average integrated NDVI values for the same period were 1.56, 1.49, and 1.45 for ungrazed, controlled and communal, respectively, i.e. a much smaller difference. This indicates that a grazing-induced development towards less ESSB and shorter-cycled annual plants with reduced ability to turn additional water in wet years into biomass is not adequately captured by seasonal NDVI metrics

Complications and mortality of Cushing’s disease: report on data collected over a 20-year period at a referral centre

Context: Cushing’s disease (CD) is rare condition burdened by several systemic complications correlated to higher mortality rates. The primary goal of clinicians is to achieve remission, but it is unclear if treatment can also increase life expectancy. Aim: To assess the prevalence of cortisol-related complications and mortality in a large cohort of CD patients attending a single referral centre. Materials and methods: The clinical charts of CD patients attending a referral hospital between 2001 and 2021 were reviewed. Results: 126 CD patients (median age at diagnosis 39 years) were included. At the last examination, 78/126 (61.9%) of the patients were in remission regardless of previous treatment strategies. Patients in remission showed a significant improvement in all the cardiovascular (CV) comorbidities (p < 0.05). The CV events were more frequent in older patients (p = 0.003), smokers and persistent CD groups (p < 0.05). Most of the thromboembolic (TE) and infective events occurred during active stages of the disease. The CV events were the most frequent cause of death. The standardized mortality ratio (SMR) resulted increased in persistent cases at the last follow-up (SMR 4.99, 95%CI [2.15; 9.83], p < 0.001) whilst it was not higher in those in remission (SMR 1.66, 95%CI [0.34; 4.85], p = 0.543) regardless of the timing or number of treatments carried out. A younger age at diagnosis (p = 0.005), a microadenoma (p = 0.002), and remission status at the last follow-up (p = 0.027) all increased survival. Furthermore, an elevated number of comorbidities, in particular arterial hypertension, increased mortality rates. Conclusions: Patients with active CD presented a poor survival outcome. Remission restored the patients’ life expectancy regardless of the timing or the types of treatments used to achieve it. Persistent CD-related comorbidities remained major risk factors

Crystallographic control and texture inheritance during mylonitization of coarse grained quartz veins

Quartz veins within Rieserferner pluton underwent deformation during post-magmatic cooling at temperature around 450 \ub0C. Different crystallographic orientations of cm-sized quartz vein crystals conditioned the evolution of microstructures and crystallographic preferred orientations (CPO) during vein-parallel simple shear up to high shear strains (\u3b3 48 10). For \u3b3 b 2, crystals stretched to ribbons of variable aspect ratios. The highest aspect ratios resulted from {m}baN glide in ribbons with c-axis sub-parallel to the shear zone vorticity Y-axis. Ribbons with c-axis orthogonal to Y (XZ-type ribbons) were stronger and hardened more quickly: they show lower aspect ratios and \ufb01ne (grain size ~10\u201320 \u3bcm) recrystallization along sets of microshear zones (\u3bcSZs) exploiting crystallographic planes. Distortion of XZ-type ribbons and recrystallization preferentially exploited the slip systems with misorientation axis close to Y. New grains of \u3bcSZs initiated by subgrain rotation recrystallization (SGR) and thereupon achieved high angle misorientations by a concurrent process of heterogeneous rigid grain rotation around Y associated with the con\ufb01ned shear within the \u3bcSZ. Dauphin\ue9 twinning occurred pervasively, but did not play a dominant role on \u3bcSZ nucleation. Recrystallization became widespread at \u3b3 N 2 and pervasive at \u3b3 48 10. Ultramylonitic quartz veins are \ufb01ne grained (~10 \u3bcm, similar to new grains of \u3bcSZ) and show a CPO banding resulting in a bulk c-axis CPO with a Y-maximum, as part of a single girdle about orthogonal to the foliation, and orientations at the pole \ufb01gure periphery at moderate to high angle to the foliation. This bulk CPO derives from steady-state SGR associated with preferential activity, in the different CPO bands, of slip systems generating subgrain boundaries with misorientation axes close to Y. The CPO of individual recrystallized bands is largely inherited from the original crystallographic orientation of the ribbons (and therefore vein crystals) from which they derived. High strain and pervasive recrystallization were not enough to reset the initial crystallographic heterogeneity and this CPO memory is explained by the dominance of SGR. This contrast with experimental observation of a rapid erasure of a pristine CPO by cannibalism from grains with the most favourably oriented slip system under dominant grain boundary migration recrystallization

The [Tc(N)(PNP)]2+ metal fragment labeled cholecystokinin-8 (CCK8) peptide for CCK-2 receptors imaging: in vitroand in vivo studies

The radiolabeling of the natural octapeptide CCK8, derivatized with a cysteine residue (Cys-Gly-CCK8), by using the metal fragment [99mTc(N)(PNP3)]2+ (PNP3 = N,N-bis(dimethoxypropylphosphinoethyl)methoxyethylamine) is reported. The [99mTc(N)(NS-Cys-Gly-CCK8)(PNP3)]+ complex was obtained according to two methods (one-step or two-step procedure) that gave the desired compound in high yield. The complex is stable in aqueous solution and in phosphate buffer. In vitro challenge experiments with an excess of cysteine and glutathione indicate that no transchelation reactions occur, confirming the high thermodynamic stability and kinetic inertness of this compound. Stability studies carried out in human and mouse serum, as well as in mouse liver homogenates, show that the radiolabeled compound remains intact for prolonged incubation at 37 degrees C. Binding properties give Kd (19.0 +/- 4.6 nmol/l) and Bmax (approximately 10(6) sites/cell) values in A431 cells overexpressing the CCK2-R. In vivo evaluation of the compound shows rapid and specific targeting to CCK2-R, a fourfold higher accumulation compared to nonreceptor expressing tumors

Local critical behaviour at aperiodic surface extended perturbation in the Ising quantum chain

The surface critical behaviour of the semi--infinite one--dimensional quantum Ising model in a transverse field is studied in the presence of an aperiodic surface extended modulation. The perturbed couplings are distributed according to a generalized Fredholm sequence, leading to a marginal perturbation and varying surface exponents. The surface magnetic exponents are calculated exactly whereas the expression of the surface energy density exponent is conjectured from a finite--size scaling study. The system displays surface order at the bulk critical point, above a critical value of the modulation amplitude. It may be considered as a discrete realization of the Hilhorst--van Leeuwen model.Comment: 13 pages, TeX file + 6 figures, epsf neede