Asymptotic stability at infinity for differentiable vector fields of the plane

Let X:R2\Dr->R2 be a differentiable (but not necessarily C1) vector field, where r>0 and Dr={z\in R2:|z|\le r}. If for some e>0 and for all p\in R2\Dr, no eigenvalue of D_p X belongs to (-e,0]\cup {z\in\C:\mathcal{R}(z)\ge 0}, then (a)For all p\in R2\Dr, there is a unique positive semi--trajectory of X starting at p; (b)\mathcal{I}(X), the index of X at infinity, is a well defined number of the extended real line [-\infty,\infty); (c) There exists a constant vector v\in R2 such that if \mathcal{I}(X) is less than zero (resp. greater or equal to zero), then the point at infinity \infty of the Riemann sphere R2\cup\set{\infty} is a repellor (resp. an attractor) of the vector field X+v.Comment: 16 pages, 7 figure

Taphonomy as a methodological framework for understanding surface funerary deposits: the human burial at the cave of El Espinoso (Ribadedeva, Asturias)

RESUMEN: Durante la Edad del Bronce en el norte de la Península Ibérica algunos grupos humanos inhumaban a sus congéneres sobre la superficie del suelo de cuevas de difícil acceso. Esta tradición cultural, muy arraigada en el País Vasco y en Cantabria, se extiende hasta la región oriental de Asturias. Este trabajo se centra en el estudio tafonómico de los restos humanos encontrados en 1993 en la cueva de El Espinoso (Ribadedeva, Asturias). La cueva fue utilizada como lugar de inhumación de un número mínimo de veinte individuos, de ambos sexos y diferentes edades. Este yacimiento constituye el único enterramiento múltiple en cueva de la Edad del Bronce documentado hasta ahora en Asturias, sumándose así a otros yacimientos de la Prehistoria Reciente de esta región, como son El Toral III, La Llana y Fuentenegroso y consolidando esta tradición funeraria a lo largo de dos mil años en el Oriente de Asturias. La tafonomía ha ofrecido un marco teórico y metodológico preciso para estudiar este tipo de yacimientos en superficie, afectados por complejos procesos post-deposicionales.ABSTRACT: During the Bronze Age the human groups of Cantabria buried their dead on the surface of narrow caves. This cultural tradition, common to the Basque Country and Cantabria, extends to eastern Asturias. This work focuses on the taphonomical study of the human remains found in 1993 in the cave of El Espinoso, located in Ribadedeva (Asturias). The cavity was used as a burial place for a minimum of twenty individuals of both sexes and different ages. This site constitutes the only collective burial cave currently known from the Bronze Age in Asturias (other later prehistoric burial caves in the region ?El Toral III, La Llana, Fuentenegroso, etc.? have single burials). A funerary tradition of cave burial lasted over two thousand years in eastern Asturias. The taphonomical analysis provides a theoritical and methodological framework adequate to the study this type of superficial deposits, affected by complex post-depositional processes.Este estudio se ha realizado a partir del Trabajo Fin de Máster del primero de los autores. La investigación ha sido apoyada por el Instituto Internacional de Investigaciones Prehistóricas de Cantabria y financiada por el Proyecto “Tracing Climatic Abrupt Change Events and Their Social Impact during the Late Pleistocene and Early Holocene (15–7 ky calBP) (HAR2013-46802-P)” financiado por el Ministerio de Economía y Competitividad de España

In-situ electrochemical synthesis of inorganic compounds for materials conservation: Assessment of their effects on the porous structure

This study refers to the application of in-situ electrochemical synthesis as an alternative method to improve the properties of porous materials against harmful external agents that deteriorate them. It is oriented to an understanding of the effects of crystallisation on the pore structure of different compounds commonly used in the restoration and conservation of porous materials (historical ceramics, building walls, sculptures, or biomedical applications). It analyses the microstructural, chemical details, and stability of the neo-formed phases that modify the pore network. The electrochemical synthesis was carried out at ambient temperature (20 °C), over high porous sandstone for crystallising Ca carbonate, Mg carbonate, Ca phosphate, and Ca oxalate compounds. Based on the neo-formed minerals, a comparison was made depending on their specific properties defining how they affected the pore structure. The characterisation included polarised light optical microscopy, environmental and field-emission scanning electron microscopy, digital image analysis, cathodoluminescence (CL-ESEM),energy-dispersive X-ray spectroscopy, and X-ray microdiffraction. Aragonite, hydromagnesite, hydroxyapatite, and whewellite were identified as the majority phases depending on the treatment. Phase transformation, dehydration, and dissolution-re-precipitation processes suggested different degrees of stability, including aragonite/calcite (CaCO3 treatment) and hydromagnesite/magnesite (MgCO3 treatment) transformations and simultaneous crystallisation of brushite/hydroxyapatite ((Ca3(PO4)2 treatment). Electrocrystallisation induced changes in inter-granular porosity, the development of secondary porosity inherent to the minerals, and differences in pore cementation depending on its mineralogy. Among the treatments, Mg carbonate reduced porosity most effectively, followed in descending order by calcium carbonate and calcium phosphate, being the calcium oxalate the less effective.This work was funded by the following projects: TOP-HERITAGE- (Technologies in Heritage Sciences (S2018/NMT_4372, Community of Madrid); MULTIMAT CHALLENGE: Multifunctional Materials for Society Challenges (S2013/MIT-2862, Community of Madrid); Additive Manufacturing: from material to application, ADITIMAT-CM (S2018/ NMT-4411, Community of Madrid); MAT2016-80875-C3-3-R, (Spanish Ministry of Science, Innovation and Universities); Author J.F.‘s participation was supported by a Spanish Ministry of Sciences, Innovation and Universities Juan de la Cierva grant

Palaeogenomics of Upper Palaeolithic to Neolithic European hunter-gatherers

Modern humans have populated Europe for more than 45,000 years1,2. Our knowledge of the genetic relatedness and structure of ancient hunter-gatherers is however limited, owing to the scarceness and poor molecular preservation of human remains from that period3. Here we analyse 356 ancient hunter-gatherer genomes, including new genomic data for 116 individuals from 14 countries in western and central Eurasia, spanning between 35,000 and 5,000 years ago. We identify a genetic ancestry profile in individuals associated with Upper Palaeolithic Gravettian assemblages from western Europe that is distinct from contemporaneous groups related to this archaeological culture in central and southern Europe4, but resembles that of preceding individuals associated with the Aurignacian culture. This ancestry profile survived during the Last Glacial Maximum (25,000 to 19,000 years ago) in human populations from southwestern Europe associated with the Solutrean culture, and with the following Magdalenian culture that re-expanded northeastward after the Last Glacial Maximum. Conversely, we reveal a genetic turnover in southern Europe suggesting a local replacement of human groups around the time of the Last Glacial Maximum, accompanied by a north-to-south dispersal of populations associated with the Epigravettian culture. From at least 14,000 years ago, an ancestry related to this culture spread from the south across the rest of Europe, largely replacing the Magdalenian-associated gene pool. After a period of limited admixture that spanned the beginning of the Mesolithic, we find genetic interactions between western and eastern European hunter-gatherers, who were also characterized by marked differences in phenotypically relevant variants.This project has received funding by the European Research Council under the European Union’s Horizon 2020 research and innovation programme under grant agreements no. 803147-RESOLUTION (to S.T.), no. 771234-PALEoRIDER (to W.H.), no. 864358 (to K.M.), no. 724703 and no. 101019659 (to K.H.). K.H. is also supported by the Deutsche Forschungsgemeinschaft (DFG FOR 2237). E.A. has received funding from the Van de Kamp fonds. PACEA co-authors of this research benefited from the scientific framework of the University of Bordeaux’s IdEx Investments for the Future programme/GPR Human Past. A.G.-O. is supported by a Ramón y Cajal fellowship (RYC-2017-22558). L. Sineo, M.L. and D.C. have received funding from the Italian Ministry of University and Research (MUR) PRIN 2017 grants 20177PJ9XF and 20174BTC4R_002. H. Rougier received support from the College of Social and Behavioral Sciences of CSUN and the CSUN Competition for RSCA Awards. C.L.S. and T. Saupe received support from the European Union through the European Regional Development Fund (project no. 2014-2020.4.01.16-0030) and C.L.S. received support from the Estonian Research Council grant PUT (PRG243). S. Shnaider received support from the Russian Science Foundation (no. 19-78 10053)

Distribution and occurrence of milkfish Chanos chanos (Forskal)

The geographic distribution of Chanos chanos; Family - Chanidae: Order Isospondyli, is discussed from available literature sources as well as actual surveys made by the writer. The existence of the species in natural waters as well as its culture in specific areas are noted. The seasonal occurrence and distribution of milkfish fry which is the basis of aquaculture for this species is enumerated. An attempt is also made to describe the nature of distribution of the species in the countries where surveys have been made or where data is available

The arrival of millets to the Atlantic coast of northern Iberia

Despite being one of the most important crops in the recent prehistory of Eurasia, the arrival and exploitation of millets in the westernmost part of Europe are still largely underexplored. Here and for the first time, we report multipronged biomolecular evidence of millet consumption along the Atlantic façade of northern Iberia through a combination of radiocarbon dating, stable isotopes, and dental calculus analyses on the human individuals found in the burial site of El Espinoso cave (Asturias, Spain). The high-resolution chronological framework established for individuals placed the burials between 1235 and 1099 cal. BC. The discovery of high ?13C values on their bone collagen and the identification of polyhedral starch grains within their dental plaque underline the relevance of C4 plants in their diet and highlights the timing of the systematic consumption of millets in the Late Bronze Age. Our data support previous regional archaeobotanical evidence and establish a more precise chronology of the dispersal of millets into northern Iberia during the Bronze Age, becoming an essential crop until the arrival of maize from America after AD 1492. This study emphasizes the importance of multidisciplinary methods to ascertain the origin and development of agricultural practices during recent prehistory.This study is part of B.G.R.’s Doctoral dissertation, supervised by A.B.M.A. and M.R.G.M. This research is funded by the research projects of the Spanish Economy, Industry and Competitiveness Ministry HAR2016-75605-R to M.R.G.M. and HAR2017- 84997-P to A.B.M.A. Part of this research, including the stable isotope analyses, was funded by the ERC Consolidator Grant (SUBSILIENCE ref. 818299), awarded to A.B.M.A. Analysis of dental calculus was carried out in the framework of the ERC Starting Grant (HIDDEN FOODS ref. 639286), awarded to E.C. The authors would like to thank C. García de Castro and B. López for giving information and allowing the sampling of Los Cinchos cave. We are grateful to L. Agudo Perez for her invaluable help during the collagen extraction protocols. The authors wish to acknowledge Dr Lawrence G. Straus (University of New Mexico) for editing the English version of this manuscript. Finally, we also thanks to two anonymous reviewers for their constructive comments that improved the manuscript

Synthesis and morpho-structural characterization of nanostructured magnesium hydroxide obtained by a hydrothermal method

Controlled magnesium hydroxide particles were successfully synthesized via a simple hydrothermal method. The influence of temperature and reaction time on the hydrothermal synthesis of Mg(OH)(2) was studied. The results provide new parameters to control the morphologies, particle sizes, agglomeration level and crystallographic structures of the brucite nanosized. The physic chemical properties of synthesized Mg(OH)(2) nanoparticles have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) combined with selected area electron diffraction (SAED), high resolution transmission electron microscopy (HR-TEM) and thermogravimetry/differential scanning calorimetry (TG/DSC). It has been shown that the prolongation of reaction time improves the crystalline degree of magnesium hydroxide particles. It was also possible to detect a relevant increase in the degree of crystallinity and a faster crystal growth with defined hexagonal morphologies in the samples obtained at higher temperature. Our results show that this simple hydrothermal route is highly interesting for the large scale production of these nanomaterials. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.This study has been supported by the Geomaterials Programme (S2009/MAT-1629) and the ESTRUMAT Programme (S2009/MAT-1585) and it has been carried out in the Department of Materials Science and Engineering and Chemical Engineering of the University Carlos III of Madrid, Spain. The authors are grateful to the National Center for Electron Microscopy (CNME) for its support with TEM

Osteomielitis y tumor de Ewing: aspectos clínicos y radiográficos comunes

La osteomielitis aguda y el tumor de Ewing, dos entidades de naturaleza bien distinta, pueden mostrar semejanzas clínicas y radiográficas. Presentamos un caso de tumor de Ewing clásico y dos de osteomielitis que plantearon sendas dudas diagnósticas. Concluimos insistiendo en la importancia de un diagnóstico diferencial definitivo precoz mediante biopsia y cultivo en estas circunstancias.Acute osteomyelitis and Ewing's sarcoma are diseases of quite different natur e which may show similar clinical and radiographic characteristics. The author s present a case of classic Ewing's sarcoma ant two case s of osteomyelitis that suposed diagnosti c doubts in each case . They conclude emphasizing on the importanc e of an early, definitive differential diagnosis in thes e circunstance s by means of a biopsy and bacteriologic culture

Application of magnesium hydroxide nanocoatings on cellulose fibers with different refining degrees

Paper aging and protection are of crucial interest for improving the preservations of library collections and archives. Highly aging-resistant cellulose fiber sheets were obtained by treatment with magnesium hydroxide nanoparticles (Mg(OH)(2)). The procedure was tested on the sheets made of bleached (B) and refined unbleached (UB) pine cellulose fibers as well as their 50%/50% mixture (M). The mor and structural properties of the obtained sheets were studied by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) methods. Stress-strain, smoothness and pH measurements were employed to determine the changes in physical-chemical characteristics of the sheets after mixing two types of the fibers and subsequent treatment with Mg(OH)(2). It has been shown that the sheets made of the fiber mixture show a higher tensile index and smoothness. The modification with Mg(OH)(2) nanoparticles induces an increase in the pH of the sheets to slightly basic values (around pH 8), facilitates the inter-fiber bonding and additionally enhances the smoothness of the sheets. Finally, by exposing the sheets to thermo-hygrometric accelerated artificial ageing, it was found that the physical properties of the treated sheets were not significantly dependent on the environmental factors.This study was supported by the Geomaterials 2 Programme (S2013/MIT_2914),the Innovation and Education Ministry (ref. MAT2013-47460-C5-5-P) and the Autonomous Region Program of Madrid, MULTIMAT CHALLENGE (ref.S2013/MIT-2862