Static Pairwise Annihilation in Complex Networks

We study static annihilation on complex networks, in which pairs of connected particles annihilate at a constant rate during time. Through a mean-field formalism, we compute the temporal evolution of the distribution of surviving sites with an arbitrary number of connections. This general formalism, which is exact for disordered networks, is applied to Kronecker, Erd\"os-R\'enyi (i.e. Poisson) and scale-free networks. We compare our theoretical results with extensive numerical simulations obtaining excellent agreement. Although the mean-field approach applies in an exact way neither to ordered lattices nor to small-world networks, it qualitatively describes the annihilation dynamics in such structures. Our results indicate that the higher the connectivity of a given network element, the faster it annihilates. This fact has dramatic consequences in scale-free networks, for which, once the ``hubs'' have been annihilated, the network disintegrates and only isolated sites are left.Comment: 7 Figures, 10 page

Luminescent gold-thallium derivatives with a pyridine-containing 12-membered aza-thioether macrocycle

The coordination modes of the ligand 2, 5, 8-trithia[9](2, 6)pyridinophane (L) to thallium(i), gold(iii) and gold(i) have been studied. Thallium(i) is coordinated by the macrocyclic ligand in [Tl(L)](PF6) (1) through all the sulfur and nitrogen atoms, in a distorted square-pyramidal geometry with the thallium(i) ion in the apical position and with the presence of an inert lone pair. Gold(iii) is bonded by the ligand only through the nitrogen of the pyridine group in [AuCl3(L)] (2), whereas two AuI-C6F5fragments coordinate the sulfur atoms next to the pyridine moiety of the ligand in [{Au(C6F5)}2(µ-L)] (3), which form a linear polymer through intermolecular aurophilic contacts. The heterometallic TlI/AuIcomplex {[Au(C6F5)2Tl]2(L)}n(4) features a polymeric structural nature with a metallic pseudo-rhombic Au2Tl2core, which repeats itself forming a zig-zag polymer. In each Au2Tl2unit only one thallium atom is bonded by the NS3donor set of the macrocyclic ligand and also forms two unsupported Au-Tl bonds with two [Au(C6F5)2]-units in an overall pseudo-octahedral geometry. The other thallium atom similarly bridges the same [Au(C6F5)2]-units and links a neighbouring Au2Tl2moiety, thus exhibiting a distorted trigonal planar geometry being bonded only to three gold atoms with unsupported Au-Tl interactions. This complex displays an interesting thermochromic behaviour showing emissions mainly resulting from MM'CT transitions at room temperature. At 77 K a dual emission appears, probably arising from the two different thallium environments. DFT calculations have been carried out in the attempt to investigate the origin of the emissions of complex4. © The Royal Society of Chemistry 2021

Continuous multi-criteria methods for crop and soil conservation planning on La Colacha (Río Cuarto, Province of Cordoba, Argentina)

Agro-areas of Arroyos Menores (La Colacha) west and south of Rand south of R?o Cuarto (Prov. of Cordoba, Argentina) basins are very fertile but have high soil loses. Extreme rain events, inundations and other severe erosions forming gullies demand urgently actions in this area to avoid soil degradation and erosion supporting good levels of agro production. The authors first improved hydrologic data on La Colacha, evaluated the systems of soil uses and actions that could be recommended considering the relevant aspects of the study area and applied decision support systems (DSS) with mathematic tools for planning of defences and uses of soils in these areas. These were conducted here using multi-criteria models, in multi-criteria decision making (MCDM); first of discrete MCDM to chose among global types of use of soils, and then of continuous MCDM to evaluate and optimize combined actions, including repartition of soil use and the necessary levels of works for soil conservation and for hydraulic management to conserve against erosion these basins. Relatively global solutions for La Colacha area have been defined and were optimised by Linear Programming in Goal Programming forms that are presented as Weighted or Lexicographic Goal Programming and as Compromise Programming. The decision methods used are described, indicating algorithms used, and examples for some representative scenarios on La Colacha area are given

Colorimetric response to anions by a "robust" copper(II) complex of a [9]aneN3 pendant arm derivative: CN- and I- selective sensing

The 1 : 1 complex [Cu(L)](BF4)2MeCN (1) of the tetradentate ligand 1-(2-quinolinylmethyl)-1,4,7-triazacyclononane (L) selectively changes its colour in the presence of CN in H2O and MeCN (without undergoing decomplexation from the macrocyclic ligand). The same complex in MeCN assumes different colours in the presence of CN or I

Gravitational perturbations of Schwarzschild spacetime at null infinity and the hyperboloidal initial value problem

We study gravitational perturbations of Schwarzschild spacetime by solving a hyperboloidal initial value problem for the Bardeen-Press equation. Compactification along hyperboloidal surfaces in a scri-fixing gauge allows us to have access to the gravitational waveform at null infinity in a general setup. We argue that this hyperboloidal approach leads to a more accurate and efficient calculation of the radiation signal than the common approach where a timelike outer boundary is introduced. The method can be generalized to study perturbations of Kerr spacetime using the Teukolsky equation.Comment: 14 pages, 9 figure

Slow 4He^{4}He Quenches Produce Fuzzy, Transient Vortices

We examine the Zurek scenario for the production of vortices in quenches of liquid $^{4}He$ in the light of recent experiments. Extending our previous results to later times, we argue that short wavelength thermal fluctuations make vortices poorly defined until after the transition has occurred. Further, if and when vortices appear, it is plausible that that they will decay faster than anticipated from turbulence experiments, irrespective of quench rates.Comment: 4 pages, Revtex file, no figures Apart from a more appropriate title, this paper differs from its predecessor by including temperature, as well as pressure, quenche

Influência do genótipo sobre a produção e a composição do leite de cabras mestiças.

Resumo: O experimento foi conduzido na EMBRAPA Caprinos e objetivou determinar o potencial de produção e a composição do leite de cabras mestiças. Foram utilizadas 35 cabras, sendo doze ½ Alpina + ½ Moxotó (½ A-M), onze ¾ Alpina + ¼ Moxotó (¾ A-M) e doze "tricross" (½ Anglo-nubiana + ¼ Alpina + ½ Moxotó). O período de lactação foi de 147 dias. As cabras eram ordenhadas duas vezes ao dia e o controle leiteiro realizado semanalmente. Os animais receberam dieta para produção de 2,5 kg de leite/dia. A produção de leite, como coletada, não foi influenciada (P>0,05) pelo genótipo. No entanto, quando esta foi corrigida para 4% de gordura, o genótipo ½ A-M foi superior (P0,05). However, when milk production was adjusted for 4% of fat, the genotype ½ Alpina + ½ Moxotó was superior to the others (P<0,05). There was no difference among genotypes for milk fat, milk protein content and total milk solids

Mechanical Properties of PMMA-Sepiolite Nanocellular Materials with a Bimodal Cellular Structure

Bimodal cellular poly(methyl methacrylate) with micron and nano sized (300 to 500 nm) cells with up to 5 weight percent of sepiolite nanoparticles and porosity from 50 weight percent to 75 weight percent are produced by solid state foaming. Uniaxial compression tests are performed to measure the effect of sepiolite concentration on the elastic modulus and the yield strength of the solid and cellular nanocomposites. Single edge notch bend tests are conducted to relate the fracture toughness of the solid and cellular nanocomposites to sepiolite concentration. The relative modulus is independent of sepiolite content to within material scatter when considering the complete porosity range. In contrast, a mild enhancement of the relative modulus is observed by the addition of sepiolite particles for the foamed nanocomposites with a porosity close to 50 percent. The relative compressive strength of the cellular nanocomposites mildly decreases as a function of sepiolite concentration. A strong enhancement of the relative fracture toughness by the addition of sepiolites is observed. The enhancement of the relative fracture toughness and the relative modulus (at 50 percent porosity) can be attributed to an improved dispersion of the particles due to foaming and the migration of micron sized aggregates from the solid phase to the microcellular pores during foaming