Raman phonons as a probe of disorder, fluctuations and local structure in doped and undoped orthorhombic and rhombohedral manganites

We present a rationalization of the Raman spectra of orthorhombic and rhombohedral, stoichiometric and doped, manganese perovskites. In particular we study RMnO3 (R= La, Pr, Nd, Tb, Ho, Er, Y and Ca) and the different phases of Ca or Sr doped RMnO3 compounds as well as cation deficient RMnO3. The spectra of manganites can be understood as combinations of two kinds of spectra corresponding to two structural configurations of MnO6 octahedra and independently of the average structure obtained by diffraction techniques. The main peaks of compounds with regular MnO6 octahedra, as CaMnO3, highly Ca doped LaMnO3 or the metallic phases of Ca or Sr doped LaMnO3, are bending and tilt MnO6 octahedra modes which correlate to R-O(1) bonds and Mn-O-Mn angles respectively. In low and optimally doped manganites, the intensity and width of the broad bands are related to the amplitude of the dynamic fluctuations produced by polaron hopping in the paramagnetic insulating regime. The activation energy, which is proportional to the polaron binding energy, is the measure of this amplitude. This study permits to detect and confirm the coexistence, in several compounds, of a paramagnetic matrix with lattice polaron together with regions without dynamic or static octahedron distortions, identical to the ferromagnetic metallic phase. We show that Raman spectroscopy is an excellent tool to obtain information on the local structure of the different micro or macro-phases present simultaneously in many manganites.Comment: Submitted to PR

Abundant bacteria in the proximal and distal intestine of healthy Siberian sturgeons (Acipenser baerii)

The gut microbiota plays a key role in animal health, including immune and metabolic homeostasis. Despite the economic relevance of the sturgeon, studies addressing the gut microbiome of this species are scarce and have focused only on the hindgut. The objective of this work was to use Illumina metabarcoding technology to compare the bacterial microbiomes of two different intestinal locations, the proximal intestine (small intestine) and the distal intestine (hindgut containing the spiral valve), of healthy Siberian sturgeons (Acipenser baerii) reared on two different farms in Spain. Although a high degree of interindividual variability was observed, certain differences between the anatomical parts and between the geographical locations were clear. The results show that the sequences corresponding to the most abundant taxa were the basis for clustering according to anatomical region (proximal and distal intestine), whereas the less abundant taxa were the basis for clustering according to the geographical location of the fish farms. Finally, the results also indicate the existence of certain bacteria that are present in the intestinal tracts of all the fish analyzed in this study; this information may be useful in future studies aiming to establish differences based upon fish health or disease

Tuna regional fisheries management organizations and the conservation of sea turtles: a reply to Godley et al

En prens

Estudio paleopatológico de la necrópolis mudéjar de la calle Colón, 3 (Novelda, Alicante)

X Congreso Nacional de Paleopatología. Univesidad Autónoma de Madrid, septiembre de 200

SEOM clinical guidelines in early stage breast cancer (2018)

Breast cancer is the most common cancer in women in our country and it is usually diagnosed in the early and potentially curable stages. Nevertheless, around 20–30% of patients will relapse despite appropriate locoregional and systemic therapies. A better knowledge of this disease is improving our ability to select the most appropriate therapy for each patient with a recent diagnosis of an early stage breast cancer, minimizing unnecessary toxicities and improving long-term efficacy

Disorder induced phase segregation in La2/3Ca1/3MnO3 manganites

Neutron powder diffraction experiments on La2/3Ca1/3MnO3 over a broad temperature range above and below the metal-insulator transition have been analyzed beyond the Rietveld average approach by use of Reverse Monte Carlo modelling. This approach allows the calculation of atomic pair distribution functions and spin correlation functions constrained to describe the observed Bragg and diffuse nuclear and magnetic scattering. The results evidence phase separation within a paramagnetic matrix into ferro and antiferromagnetic domains correlated to anistropic lattice distortions in the vicinity of the metal-insulator transition.Comment: 3 pages, 4 figures. Submitted to Phys. Rev. Lett. Figure 1 replace

On-Surface Driven Formal Michael Addition Produces m-Polyaniline Oligomers on Pt(111)

On-surface synthesis is emerging as a highly rational bottom-up methodology for the synthesis of molecular structures that are unattainable or complex to obtain by wet chemistry. Here, oligomers of meta-polyaniline, a known ferromagnetic polymer, were synthesized from para-aminophenol building-blocks via an unexpected and highly specific on-surface formal 1, 4 Michael-type addition at the meta position, driven by the reduction of the aminophenol molecule. We rationalize this dehydrogenation and coupling reaction mechanism with a combination of in situ scanning tunneling and non-contact atomic force microscopies, high-resolution synchrotron-based X-ray photoemission spectroscopy and first-principles calculations. This study demonstrates the capability of surfaces to selectively modify local molecular conditions to redirect well-established synthetic routes, such as Michael coupling, towards the rational synthesis of new covalent nanostructures

First modern human settlement recorded in the Iberian hinterland occurred during Heinrich Stadial 2 within harsh environmental conditions

As the south-westernmost region of Europe, the Iberian Peninsula stands as a key area for understanding the process of modern human dispersal into Eurasia. However, the precise timing, ecological setting and cultural context of this process remains controversial concerning its spatiotemporal distribution within the different regions of the peninsula. While traditional models assumed that the whole Iberian hinterland was avoided by modern humans due to ecological factors until the retreat of the Last Glacial Maximum, recent research has demonstrated that hunter-gatherers entered the Iberian interior at least during Solutrean times. We provide a multi-proxy geoarchaeological, chronometric and paleoecological study on human–environment interactions based on the key site of Peña Capón (Guadalajara, Spain). Results show (1) that this site hosts the oldest modern human presence recorded to date in central Iberia, associated to pre-Solutrean cultural traditions around 26, 000 years ago, and (2) that this presence occurred during Heinrich Stadial 2 within harsh environmental conditions. These findings demonstrate that this area of the Iberian hinterland was recurrently occupied regardless of climate and environmental variability, thus challenging the widely accepted hypothesis that ecological risk hampered the human settlement of the Iberian interior highlands since the first arrival of modern humans to Southwest Europe. © 2021, The Author(s)

Revista de Vertebrados de la Estación Biológica de Doñana

Descripción de un nuevo género y de una nueva especie Iberocypris palaciosi N.GEN.N.SO (Pisces, cyprinidae).Resultados de los censos d e aves acuáticas en Andalucía Occidental durante el invierno1978-79Interacciones en la alimentación de las larvas de dos especies de tritones. (Triturus marmoratus y Triturus boscai).Utilización del espacio en una comunidad de lacertidos del matorral mediterráneo en la Reserva Biológica de DoñanaMorfología dentaria de las liebres europeas (Lagomorpha, leporidae).El conejo, Oryctolagus cuniculus en Andalucía Occidental: Parámetros corporales y curva de crecimientoObservaciones de foca monje (Monachus monachus Herm.) en las costas del sureste de la Península Ibérica.Presencia de pejerrey Atherina (Hepsetia) boyeri, Risso 1810; Pisces ( Atherinidae) en la laguna de Zoñar (Córdoba, SO de España).Nuevas citas de la "loina" Chondrostoma (Machaerochilus) toxostoma arrigonis Stein. (pisces, cyprinidae) en EspañaRelativa subalimentación de Falco naumanni durante el periodo no reproductor en el valle del GuadalquivirComadrejas alimentandose de carroña.Agrupamientos de Alytes cisternasii bajo el mismo refugioDescripción de un nuevo género de quiróptero neotropical de la familia MolossidaeAlgunas notas sobre Platalea leucorodia en GaliciaInicidencia del murciélago hematófago Desmodus rotundus sobre los indígenas Yanomani de VenezuelaRitmo de actividad de algunos ratones de los llanos de Apure (Venezuela)Presencia del topillo campesino ibérico, Microtus arvalis asturianus Miller, 1908 en la meseta del DueroFalco columbarius EsmerejónCiconia ciconia CigüeñaNycticorax nycticorax MartinetePeer reviewe