Two-phase densification of cohesive granular aggregates

When poured into a container, cohesive granular materials form low-density, open granular aggregates. If pressed upon with a ram, these aggregates densify by particle rearrangement. Here we introduce experimental evidence to the effect that particle rearrangement is a spatially heterogeneous phenomenon, which occurs in the form of a phase transformation between two configurational phases of the granular aggregate. We then show that the energy landscape associated with particle rearrangement is consistent with our interpretation of the experimental results. Besides affording insight into the physics of the granular state, our conclusions are relevant to many engineering processes and natural phenomena.Comment: 7 pages, 3 figure

AVENA FORRAJERA "INIA COLUMBA": un cultivar para siembras tempranas y uso en oble propósito (pastoreo y reservas)

INIA Columba1 (LE Px133) es un cultivar de avena forrajero producto del cruzamiento de una planta de Estan- zuela 1095a (seleccionada por su lento enroyamiento) e INIA Polaris, desarrollada en el marco del programa de mejoramiento genético de avena forrajera en INIA La Estanzuela. Ha sido seleccionada por su buena adaptación a siem- bras tempranas, una fenología adecuada al pastoreo, resistencia parcial a roya de la hoja y alta producción de grano, todos elementos importantes para mejorar la producción de los verdeos de invierno

Progressive Compromise of Nouns and Action Verbs in Posterior Cortical Atrophy

Processing of nouns and action verbs can be differentially compromised following lesions to posterior and anterior/motor brain regions, respectively. However, little is known about how these deficits progress in the course of neurodegeneration. To address this issue, we assessed productive lexical skills in a patient with posterior cortical atrophy (PCA) at two different stages of his pathology. On both occasions, he underwent a structural brain imaging protocol and completed semantic fluency tasks requiring retrieval of animals (nouns) and actions (verbs). Imaging results were compared with those of controls via voxel-based morphometry (VBM), whereas fluency performance was compared to age-matched norms through Crawford’s t-tests. In the first assessment, the patient exhibited atrophy of more posterior regions supporting multimodal semantics (medial temporal and lingual gyri), together with a selective deficit in noun fluency. Then, by the second assessment, the patient’s atrophy had progressed mainly toward fronto-motor regions (rolandic operculum, inferior and superior frontal gyri) and subcortical motor hubs (cerebellum, thalamus), and his fluency impairments had extended to action verbs. These results offer unprecedented evidence of the specificity of the pathways related to noun and action-verb impairments in the course of neurodegeneration, highlighting the latter’s critical dependence on damage to regions supporting motor functions, as opposed to multimodal semantic processes

Folding energetics in thin-film diaphragms

We perform experiments to elucidate how the folding patterns of thin-film diaphragms subject to in-plane isotropic and anisotropic compressive strains depend on the shape, thickness and size of the diaphragms. We then use a constrained von K\ue1rm\ue1n model to relate the experimental results to the energetics of folding. We show that the differences between the isotropic and the anisotropic cases can be traced back to the structure of the membraneous energy density function. In the isotropic case, we find foldings which satisfy the boundary conditions and minimize the membraneous energy. In the anisotropie case, no such foldings exist, but we are able to construct sequences of increasingly fine foldings which satisfy the boundary conditions and whose membraneous energies converge to the infimum. In both cases, we obtain solutions by allowing bending to select a preferred folding. The solutions compare well with the experimental observations

Patagonian Aridification at the Onset of the Mid‐Miocene Climatic Optimum

Fossil‐rich sediments of the Santa Cruz Formation, Patagonia, Argentina, span the initiation of the Miocene Climatic Optimum (MCO), the most recent period of warm and wet conditions in the Cenozoic. These conditions drove the expansion of tropical and subtropical ecosystems to much higher latitudes, with the fossiliferous Santa Cruz Formation recording one of the southernmost examples. We collected new carbon and oxygen isotope compositions of herbivore tooth enamel from fossils ~17.4 to 16.4 Ma in age to investigate ecological and climatic changes across the initiation of the MCO. Enamel δ13C values are consistent with a C3‐dominated ecosystem with moderate precipitation and a mix of wooded and more open areas. Serially sampled teeth reveal little zoning in δ13C and δ18O values, suggesting little seasonal variation in water and plant isotope compositions or seasonal changes in diet. Carbon isotope‐based estimates of mean annual precipitation (MAP) are consistent with aridification, with MAP decreasing from ~1,000 ± 235 mm/yr at 17.4 Ma to ~525 ± 105 mm/yr at the start of the climatic optimum (~16.9 Ma). This decrease corresponds to increasing global temperatures, as indicated by marine proxy records, and was followed by a rebound to ~840 ± 270 mm/yr by ~16.4 Ma. In comparison to a modern mean annual temperature (MAT) in the region of ~8°C, oxygen isotopes indicate high MAT (at least 20°C) at the onset of the MCO at 16.9 Ma and a significant increase in MAT to ~25°C by 16.4 Ma

Pubertal exposure to dietary advanced glycation end products disrupts ductal morphogenesis and induces atypical hyperplasia in the mammary gland

Abstract Background Advanced glycation end products (AGEs) are reactive metabolites intrinsically linked with modern dietary patterns. Processed foods, and those high in sugar, protein and fat, often contain high levels of AGEs. Increased AGE levels are associated with increased breast cancer risk, however their significance has been largely overlooked due to a lack of direct cause-and-effect relationship. Methods To address this knowledge gap, FVB/n mice were fed regular, low AGE, and high AGE diets from 3 weeks of age and mammary glands harvested during puberty (7 weeks) or adulthood (12 weeks and 7 months) to determine the effects upon mammary gland development. At endpoint mammary glands were harvested and assessed histologically (n ≥ 4). Immunohistochemistry and immunofluorescence were used to assess cellular proliferation and stromal fibroblast and macrophage recruitment. The Kruskal–Wallis test were used to compare continuous outcomes among groups. Mammary epithelial cell migration and invasion in response to AGE-mediated fibroblast activation was determined in two-compartment co-culture models. In vitro experiments were performed in triplicate. The nonparametric Wilcoxon rank sum test was used to compare differences between groups. Results Histological analysis revealed the high AGE diet delayed ductal elongation, increased primary branching, as well as increased terminal end bud number and size. The high AGE diet also led to increased recruitment and proliferation of stromal cells to abnormal structures that persisted into adulthood. Atypical hyperplasia was observed in the high AGE fed mice. Ex vivo fibroblasts from mice fed dietary-AGEs retain an activated phenotype and promoted epithelial migration and invasion of non-transformed immortalized and tumor-derived mammary epithelial cells. Mechanistically, we found that the receptor for AGE (RAGE) is required for AGE-mediated increases in epithelial cell migration and invasion. Conclusions We observed a disruption in mammary gland development when mice were fed a diet high in AGEs. Further, both epithelial and stromal cell populations were impacted by the high AGE diet in the mammary gland. Educational, interventional, and pharmacological strategies to reduce AGEs associated with diet may be viewed as novel disease preventive and/or therapeutic initiatives during puberty

Stromal PDGFR-α Activation Enhances Matrix Stiffness, Impedes Mammary Ductal Development, and Accelerates Tumor Growth

The extracellular matrix (ECM) is critical for mammary ductal development and differentiation, but how mammary fibroblasts regulate ECM remodeling remains to be elucidated. Herein, we used a mouse genetic model to activate platelet derived growth factor receptor-alpha (PDGFRα) specifically in the stroma. Hyperactivation of PDGFRα in the mammary stroma severely hindered pubertal mammary ductal morphogenesis, but did not interrupt the lobuloalveolar differentiation program. Increased stromal PDGFRα signaling induced mammary fat pad fibrosis with a corresponding increase in interstitial hyaluronic acid (HA) and collagen deposition. Mammary fibroblasts with PDGFRα hyperactivation also decreased hydraulic permeability of a collagen substrate in an in vitro microfluidic device assay, which was mitigated by inhibition of either PDGFRα or HA. Fibrosis seen in this model significantly increased the overall stiffness of the mammary gland as measured by atomic force microscopy. Further, mammary tumor cells injected orthotopically in the fat pads of mice with stromal activation of PDGFRα grew larger tumors compared to controls. Taken together, our data establish that aberrant stromal PDGFRα signaling disrupts ECM homeostasis during mammary gland development, resulting in increased mammary stiffness and increased potential for tumor growth

The late Oligocene-early Miocene marine transgression of Patagonia

The most important Cenozoic marine transgression in Patagonia occurred during the late Oligocene–early Miocene when marine waters of Pacific and Atlantic origin flooded most of southern South America including the present Patagonian Andes between ~41° and 47° S. The age, correlation, and tectonic setting of the different marine formations deposited during this period are debated. However, recent studies based principally on U–Pb geochronology and Sr isotope stratigraphy, indicate that all of these units had accumulated during the late Oligocene–early Miocene. The marine transgression flooded a vast part of southern South America and, according to paleontological data, probably allowed for the first time in the history of this area a transient connection between the Pacific and Atlantic oceans. Marine deposition started in the late Oligocene–earliest Miocene (~26–23 Ma) and was probably caused by a regional event of extension related to major plate reorganization in the Southeast Pacific. Progressive extension and crustal thinning allowed a generalized marine flooding of Patagonia that reached its maximum extension at ~20 Ma. It was followed by a phase of compressive tectonics that started around 19–16 Ma and led to the growth of the Patagonian Andes. The youngest (~19–15 Ma) marine deposits that accumulated in the eastern Andean Cordillera and the extra-Andean regions are coeval with fluvial synorogenic deposits and probably had accumulated under a compressive regime.Fil: Encinas, Alfonso. Universidad de Concepción; ChileFil: Folguera Telichevsky, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Bechis, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Diversidad Cultural y Procesos de Cambio. Universidad Nacional de Río Negro. Instituto de Investigaciones en Diversidad Cultural y Procesos de Cambio; ArgentinaFil: Finger, Kennet. University of California; Estados UnidosFil: Zambrano, Patricio. Universidad Andrés Bello; ChileFil: Pérez, Andrés Felipe. Universidad de Concepción; ChileFil: Bernabé, Pablo. Universidad de Concepción; ChileFil: Tapia, Francisca. Universidad de Concepción; ChileFil: Riffo, Ricardo. Universidad de Concepción; ChileFil: Buatois, Luis Alberto. University of Saskatchewan; CanadáFil: Orts, Darío Leandro. Universidad Nacional de Río Negro. Sede Alto Valle. Instituto de Investigaciones en Paleobiología y Geología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nielsen, Sven Nikolaus. Universidad Austral de Chile. Instituto de Ciencias de la Tierra; ChileFil: Valencia, Víctor V.. Washington State University; Estados UnidosFil: Cuitiño, José Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; ArgentinaFil: Oliveros, Verónica. Universidad de Concepción; ChileFil: De Girolamo Del Mauro, Lizet. Universidad de Concepción; ChileFil: Ramos, Victor Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentin