Regional Drought Modes in Iran Using the SPI: The Effect of Time Scale and Spatial Resolution

In the present paper, regional drought modes in Iran are identified applying the Principal Component Analysis (PCA) and Varimax rotation to the Standardized Precipitation Index (SPI) computed on different time scales. Data used include gridded monthly precipitation covering the period 1951–2007 retrieved from the Global Precipitation Climatology Centre (GPCC) archive with different spatial resolutions (2.5, 1 and 0.5° resolution). The objective of the study is twofold: (i) Investigate the stability of drought spatial modes as a function of the SPI time scales used for monitoring the different kinds of drought, (ii) Evaluate the impact of the spatial resolution of gridded data on drought regionalization. For the coarse spatial resolution of 2.5°, results show four drought modes of distinct variability, which remain quite stable when the SPI time scale is varied from 1- to 24-month. Differently, for higher spatial resolutions drought modes appear more sensitive to the index time scale and become less spatially homogeneous as the time scale is increased. Moreover, the number of identified modes (sub-regions) may reduce to three or two, but in all cases the most well defined sub-region appears to be the southern one. This suggests that both the spatial resolution of precipitation data and the time scale may affect drought regionalization, i.e. the number of drought modes and their spatial homogeneity.     

The Ketogenic Diet Reduces the Harmful Effects of Stress on Gut Mitochondrial Biogenesis in a Rat Model of Irritable Bowel Syndrome

Functional alterations in irritable bowel syndrome have been associated with defects in bioenergetics and the mitochondrial network. Effects of high fat, adequate-protein, low carbohydrate ketogenic diet (KD) involve oxidative stress, inflammation, mitochondrial function, and biogenesis. The aim was to evaluate the KD efficacy in reducing the effects of stress on gut mitochondria. Newborn Wistar rats were exposed to maternal deprivation to induce IBS in adulthood. Intestinal inflammation (COX-2 and TRL-4); cellular redox status (SOD 1, SOD 2, PrxIII, mtDNA oxidatively modified purines); mitochondrial biogenesis (PPAR-γ, PGC-1α, COX-4, mtDNA content); and autophagy (Beclin-1, LC3 II) were evaluated in the colon of exposed rats fed with KD (IBD-KD) or standard diet (IBS-Std), and in unexposed controls (Ctrl). IBS-Std rats showed dysfunctional mitochondrial biogenesis (PPAR-γ, PGC-1α, COX-4, and mtDNA contents lower than in Ctrl) associated with inflammation and increased oxidative stress (higher levels of COX-2 and TLR-4, SOD 1, SOD 2, PrxIII, and oxidatively modified purines than in Ctrl). Loss of autophagy efficacy appeared from reduced levels of Beclin-1 and LC3 II. Feeding of animals with KD elicited compensatory mechanisms able to reduce inflammation, oxidative stress, restore mitochondrial function, and baseline autophagy, possibly via the upregulation of the PPAR-γ/PGC-1α axis.     

High temperature melt viscosity and fragile to strong transition in Zr–Cu–Ni–Al–Nb(Ti) and Cu47Ti34Zr11Ni8 bulk metallic glasses

The molten viscous behavior of Vitreloy 106, 106a, 105 and 101 bulk metallic glass-forming alloys was investigated at temperatures above T_liq. Couette concentric cylinder viscometry was used to determine the isothermal and continuous cooling melt viscosities. Isothermal three point beam bending measurements of the viscosity in the vicinity of T_g revealed a kinetically stronger liquid at low temperatures than at high temperatures, near T_liq. This behavior is revealed to be the result of a fragile to strong transition in the undercooled liquid, possibly due to polyamorphism.     

Recycling of Screen Glass Into New Traditional Ceramic Materials

The cleaned cathode ray tube (CRT) glass comes from the dismantling plant of TV and PC color kinescopes and has been used to completely replace both feldspathic and inert components of a traditional ceramic body. Panel glass has been added (up to 20 wt%) to a mixture of two commercial ball clays in order to obtain laboratory tiles sintered at 1210°C. Densification has been studied according to ISO rules, while sinterability has been estimated by optical dilatometry. The samples obtained showed main properties similar to commercial ceramic floor and/or wall tiles.     

Graphene sublattice symmetry and isospin determined by circular dichroism in angle-resolved photoemission spectroscopy

The Dirac-like electronic structure of graphene originates from the equivalence of the two basis atoms in the honeycomb lattice. We show that the characteristic parameters of the initial state wave function (sublattice symmetry and isospin) can be determined using angle-resolved photoemission spectroscopy (ARPES) with circularly polarized synchrotron radiation. At a photon energy of hν = 52 eV, transition matrix element effects can be neglected allowing us to determine sublattice symmetry and isospin with high accuracy using a simple theoretical model.     

Reaction Pathways in the Reduction of NO x Species by CO over Pt–Ba/Al2O3: Lean NO x Trap Catalytic Systems

The reduction by CO of NO _x species stored over Pt–Ba/Al₂O₃ Lean NO _x Trap systems is analysed in this work. The reaction mechanisms and pathways leading to N₂ formation both under dry and wet conditions are investigated by complementary transient dynamic experiments and FTIR analyses.     

NH3–NO/NO2 SCR for Diesel Exhausts Aftertreatment: Reactivity, Mechanism and Kinetic Modelling of Commercial Fe- and Cu-Promoted Zeolite Catalysts

The activity and the mechanism of the main reactions in the NO/NO₂–NH₃ SCR reacting system were comparatively investigated over a Fe- and a Cu-promoted commercial zeolite catalyst for the aftertreatment of Diesel exhausts. A dynamic micro-kinetic model in close agreement with all the details of the SCR catalytic chemistry was also developed.     

Effects of orlistat therapy on plasma concentrations of oxygenated and hydrocarbon carotenoids

Orlistat is a lipase inhibitor that is applied for treating obesity. Lipases are required for digestion and absorption of dietary lipids and fat-soluble vitamins and carotenoids. The aim of this study was to compare the effects of orlistat therapy on plasma concentrations of oxygenated (β-cryptoxanthin, lutein/zeaxanthin) and hydrocarbon (α-, β-carotene, lycopene) carotenoids. Six patients with a body mass index (BMI)≥30 kg/m² received 360 mg/d orlistat over 4.5 mon. Plasma carotenoid concentrations were determined at baseline (T ₀) and after 3 (T ₃) and 4.5 mon (T _4.5) along with anthropometric, dietary, and biochemical indices, including plasma lipids, retinol, α- and γ-tocopherols, and FA. Baseline BMI was 32.7±1.97 kg/m². Five of six patients lost weight; the average weight loss was 3.6±2.4% (P=0.47). There were no significant changes in dietary carotenoid intakes. In contrast, plasma α-and β-carotene concentrations decreased significantly from T ₀ to T _4.5 by 45% (P=0.006) and 32% (P=0.013), respectively. Plasma lycopene decreased from T ₀ to T ₃ but increased again from T ₃ to T _4.5, while β-cryptoxanthin and lutein/zeaxanthin concentrations did not change. There were no significant alterations in tocopherol, retinol, and FA concentrations. In conclusion, even though weight loss was not significant, orlistat therapy was associated with significant decreases in plasma concentrations of the highly lipophilic hydrocarbon carotenoids, α- and β-carotene.