Modern cave pollen in an arid environment and its application to describe palaeorecords

This paper presents pollen-analytical results of surface sediments from two caves in southeastern Spain, a region of particular interest because of its relatively arid climate and entomophilous-dominated flora. The positive role of aridity on pollen preservation in cave sediments is confirmed, and is reflected by samples with high pollen concentration and number of taxa, and low percentages of indeterminable palynomorphs. Pollen spectra from cave sediments, while strongly influenced by biotic transport, may represent the surrounding vegetation acceptably well, even better than the external pollen rain in which is biased by very abundant production and dispersal of wind-pollinated taxa.Análisis de polen moderno en cuevas con un clima árido y su aplicación para describir los paleoregistros. Se presentan los resultados del análisis polínico de sedimentos superficiales de dos cavidades del SE ibérico, región caracterizada por un clima relativamente árido y una vegetación principalmente entomófila. Queda confirmado el valor de la aridez para la preservación polínica en los sedimentos de cavidades kársticas, encontrándose valores elevados de concentración polínica y del número de taxones, así como bajos porcentajes de pólenes indeterminables. Los espectros polínicos de sedimentos de cuevas, aún estando fuertemente influenciados por el transporte biótico, pueden constituir un buen indicador de la vegetación que crece en los alrededores de la cavidad, incluso mejor que la propia lluvia polínica externa

Tetranuclear coordination assemblies based on half-sandwich ruthenium(II) complexes. Non covalent binding to DNA and cytotoxicity.

The reaction of [(cymene)RuCl2]2 with K2Hoxonate (H3oxonic = 4,6-dihydroxy-2-carboxy-1,3,5-triazine acid) in methanol leads to the formation of the dinuclear half-sandwich ruthenium(II) complex [(cymene)2Ru2(\u3bc-Hoxonato)Cl2] (1a). Removal of the chloride ligands of 1a by treatment with AgCF3SO3 yields [(cymene)2Ru2(\u3bc-Hoxonato)(CF3SO3)2] (1b), which, upon posterior reaction with N,N'-linkers (L = 4,4'-bipyridine (4,4'-bpy), 4,7-phenantroline (4,7-phen)), gives rise to the formation of the tetranuclear open boxes [(cymene)4Ru4(\u3bc-Hoxonato)2(\u3bc-N,N'-L)2](CF3SO3)4 (2a, L = 4,4'-bpy; 2b, L = 4,7-phen). These systems have been characterized by 1HNMR, UV-vis, and ESI-MS. The single-crystal structures of the dinuclear precursor 1a and of the clathrate 2b 824,7-phen have been determined. The interaction of these systems with cysteine, mononucleotides, and calf-thymus DNA has been studied by means of 1HNMR, UV-vis, circular dicroism, competitive binding assays, and atomic force microscopy imaging. The results show that the robust tetracationic ruthenium(II) cyclic systems 2a and 2b do not give ligand exchange reactions toward biorelevant ligands. Nevertheless, these systems are able to noncovalently bind to DNA, probably at the surface of the major groove, inducing significant conformational changes in this biomolecule. It is also interesting to note that compounds 2a and 2b, in spite of only giving supramolecular interactions with biomolecules, exhibit antitumor activity, particularly toward the human ovarian cancer cell line A2780cisR, showing acquired resistance to cisplatin, with respective 4.6 and 8.3 microM IC50 values

Blockchain for economically sustainable wireless mesh networks

This is the peer reviewed version of the following article: Kabbinale, AR, Dimogerontakis, E, Selimi, M, et al. Blockchain for economically sustainable wireless mesh networks. Concurrency Computat Pract Exper. 2020; 32:e5349, which has been published in final form at https://doi.org/10.1002/cpe.5349. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Decentralization, in the form of mesh networking and blockchain, two promising technologies, is coming to the telecommunications industry. Mesh networking allows wider low-cost Internet access with infrastructures built from routers contributed by diverse owners, whereas blockchain enables transparency and accountability for investments, revenue, or other forms of economic compensations from sharing of network traffic, content, and services. Crowdsourcing network coverage, combined with crowdfunding costs, can create economically sustainable yet decentralized Internet access. This means that every participant can invest in resources and pay or be paid for usage to recover the costs of network devices and maintenance. While mesh networks and mesh routing protocols enable self-organized networks that expand organically, cryptocurrencies and smart contracts enable the economic coordination among network providers and consumers. We explore and evaluate two existing blockchain software stacks, Hyperledger Fabric (HLF) and Ethereum geth with Proof of Authority (PoA) intended as a local lightweight distributed ledger, deployed in a real city-wide production mesh network and in laboratory network. We quantify the performance and bottlenecks and identify the current limitations and opportunities for improvement to serve locally the needs of wireless mesh networks, without the privacy and economic cost of relying on public blockchains.This paper has been supported by the AmmbrTech Group, the Spanish Government TIN2016‐77836‐C2‐2‐R and the European Community H2020 Programme netCommons (H2020‐688768). The authors would like to thank the people from the Guifi.net (Guifi‐Sants) community network for hosting the servers and supporting the experiments.Peer ReviewedPostprint (author's final draft

Magnetic fields and Sunyaev-Zel'dovich effect in galaxy clusters

In this work we study the contribution of magnetic fields to the Sunyaev Zeldovich (SZ) effect in the intracluster medium. In particular we calculate the SZ angular power spectrum and the central temperature decrement. The effect of magnetic fields is included in the hydrostatic equilibrium equation by splitting the Lorentz force into two terms one being the force due to magnetic pressure which acts outwards and the other being magnetic tension which acts inwards. A perturbative approach is adopted to solve for the gas density profile for weak magnetic fields (< 4 micro G}). This leads to an enhancement of the gas density in the central regions for nearly radial magnetic field configurations. Previous works had considered the force due to magnetic pressure alone which is the case only for a special set of field configurations. However, we see that there exists possible sets of configurations of ICM magnetic fields where the force due to magnetic tension will dominate. Subsequently, this effect is extrapolated for typical field strengths (~ 10 micro G) and scaling arguments are used to estimate the angular power due to secondary anisotropies at cluster scales. In particular we find that it is possible to explain the excess power reported by CMB experiments like CBI, BIMA, ACBAR at l > 2000 with sigma_8 ~ 0.8 (WMAP 5 year data) for typical cluster magnetic fields. In addition we also see that the magnetic field effect on the SZ temperature decrement is more pronounced for low mass clusters ( ~ 2 keV). Future SZ detections of low mass clusters at few arc second resolution will be able to probe this effect more precisely. Thus, it will be instructive to explore the implications of this model in greater detail in future works.Comment: 20 pages, 8 figure

Crystalline fibres of a covalent organic framework through bottom-up microfluidic synthesis

A microfluidic chip has been used to prepare fibres of a porous polymer with high structural order, setting a precedent for the generation of a wide variety of materials using this reagent mixing approach that provides unique materials not accessible easily through bulk processes. The reaction between 1,3,5-tris(4-aminophenyl)benzene and 1,3,5-benzenetricarbaldehyde in acetic acid under continuous microfluidic flow conditions leads to the formation of a highly crystalline and porous covalent organic framework (hereafter denoted as MF-COF-1), consisting of fibrillar micro-structures, which have mechanical stability that allows for direct drawing of objects on a surfaceFinancial support from Spanish Government (Projects MAT2013-46753-C2-1-P and CTQ2014-53486-R) and FEDER are acknowledged. A. A. and J. P. L. would like to thank the financial support from the Swiss National Science Foundation (SNSF) through the project no. 200021_16017

Photon, Neutrino and Charged Particle Spectra from R-violating Gravitino Decays

We study photonic, neutrino and charged particle signatures from slow decays of gravitino dark matter in supersymmetric theories where R-parity is explicitly broken by trilinear operators. Photons and (anti-)fermions from loop and tree-level processes give rise to spectra with distinct features, which, if observed, can give crucial input on the possible mass of the gravitino and the magnitude and flavour structure of R-violating operators. Within this framework, we make detailed comparisons of the theoretical predictions to the recent experimental data from PAMELA, ATIC and Fermi LAT.Comment: Version published in Phys. Lett.

Comprometimentos cognitivos em pacientes com gliomas de baixo grau e gliomas de alto grau

OBJECTIVE: The relationship between brain tumors and cognitive deficits is well established in the literature. However, studies investigating the cognitive status in low and high-grade gliomas patients are scarce, particularly in patients with average or lower educational level. This study aimed at investigating the cognitive functioning in a sample of patients with low and high-grade gliomas before surgical intervention. METHOD: The low-grade (G1, n=19) and high-grade glioma (G2, n=8) patients underwent a detailed neuropsychological assessment of memory, executive functions, visuo-perceptive and visuo-spatial abilities, intellectual level and language. RESULTS: There was a significant impairment on verbal and visual episodic memory, executive functions including mental flexibility, nominal and categorical verbal fluency and speed of information processing in G2. G1 showed only specific deficits on verbal and visual memory recall, mental flexibility and processing speed. CONCLUSION: These findings demonstrated different levels of impairments in the executive and memory domains in patients with low and high grade gliomas.OBJETIVO: A associação entre tumores cerebrais e déficits cognitivos é bem estabelecida na literatura. No entanto, estudos sobre a cognição de pacientes com gliomas de baixo e alto grau são escassos, especialmente, em sujeitos com baixa escolaridade. Este estudo investigou o funcionamento cognitivo de uma amostra de pacientes com gliomas de baixo e alto grau antes da intervenção cirúrgica. MÉTODO: Os pacientes com glioma de baixo grau (G1, n=19) e alto grau (G2, n=8) foram avaliados quanto à memória, funções executivas, habilidades visuo-perceptivas e visuo-espaciais, nível intelectual e linguagem. RESULTADOS: Houve prejuízo significativo em G2 na memória episódica verbal e visual, funções executivas incluindo flexibilidade mental, fluência verbal nominal e categórica e velocidade de processamento de informações. G1 demonstrou apenas déficits específicos de evocação verbal e visual, flexibilidade mental e velocidade de processamento. CONCLUSÃO: Estes achados demonstraram níveis diferenciados de comprometimento nos domínios executivos e mnésticos de pacientes com gliomas de baixo e alto grau

Enhanced Joule Heating in Umbral Dots

We present a study of magnetic profiles of umbral dots (UDs) and its consequences on the Joule heating mechanisms. Hamedivafa (2003) studied Joule heating using vertical component of magnetic field. In this paper UDs magnetic profile has been investigated including the new azimuthal component of magnetic field which might explain the relatively larger enhancement of Joule heating causing more brightness near circumference of UD.Comment: 8 pages, 1 figure, accepted in Solar Physic

Inflation, quantum fields, and CMB anisotropies

Inflationary cosmology has proved to be the most successful at predicting the properties of the anisotropies observed in the cosmic microwave background (CMB). In this essay we show that quantum field renormalization significantly influences the generation of primordial perturbations and hence the expected measurable imprint of cosmological inflation on the CMB. However, the new predictions remain in agreement with observation, and in fact favor the simplest forms of inflation. In the near future, observations of the influence of gravitational waves from the early universe on the CMB will test our new predictions.Comment: 11 pages, 1 figure, Awarded with the fourth prize in the Gravity Research Foundation 2009 Essay Competitio

Microscopic study of the He2-SF6 trimers

The He2-SF6 trimers, in their different He isotopic combinations, are studied both in the framework of the correlated Jastrow approach and of the Correlated Hyperspherical Harmonics expansion method. The energetics and structure of the He-SF6 dimers are analyzed, and the existence of a characteristic rotational band in the excitation spectrum is discussed, as well as the isotopic differences. The binding energies and the spatial properties of the trimers, in their ground and lowest lying excited states, obtained by the Jastrow ansatz are in excellent agreement with the results of the converged CHH expansion. The introduction of the He-He correlation makes all trimers bound by largely suppressing the short range He-He repulsion. The structural properties of the trimers are qualitatively explained in terms of the shape of the interactions, Pauli principle and masses of the constituents.Comment: 17 pages, 5 figures. Submitted to PR