5,626 research outputs found
Análisis de las zonas de recarga de acuíferos mediante la percepción remota: aplicación a la cuenca de Almoloya del Río
Se plantea en este trabajo la conveniencia de disponer de herramientas que permitan la obtención de datos espaciales de los fenómenos relacionados con la hidrología superficial y subterránea. EL objeto de disponer de datos espaciales es el describir de una manera completa el objeto de disponer de datos espaciales es el describir de una manera completa el objeto de estudio y sobre todo tener herramientas más efectivas para aprovechar el empleo de modelos en computador digital. Se describen las disciplinas de Cartografía, Fotogrametría y Percepción Remota y su aplicación a los estudios geohidrológicos. La metodología se aplica en la zona de Almoloya del río en la cuenca alta del río Lerma. Básicamente se emplea cartografía INEGI a varias escalas, fotografías aéreas, ortofotos y dos imágenes LANDSAT digitales tomadas por el sensor MSS en la zona de estudio. Estas últimas fueron procesadas en microcomputadora mediante los sistemas SPIPRII e IDRISI. La metodología abarca el empleo de todos los recursos de la percepción remota. Mediante fotografías aéreas se ha determinado la evolución, desde los años 70 hasta 1995, de la zona lagunar comprendida en la zona y mediante clasificación supervisada de datos espectrales se han obtenido las distribuciones de tres clases principales de terrenos en lo referente a recarga. Este análisis ha permitido constatar, una reducción progresiva no lineal debido a los fenómenos naturales y a las obras emprendidas por los diferentes organismos y el área de estudio. Estas distribuciones están correlacionadas con datos geológicos y de taxonomía de suelos. Se plantean propuestas para la zona de Almoloya del río y en general una metodología para aplicar en futuros estudios que requieran datos espaciales para ser integrados en sistemas de información geográfica o en modelos
Single-molecule electrical contacts on silicon electrodes under ambient conditions
The ultimate goal in molecular electronics is to use individual molecules as the active electronic component of a real-world sturdy device. For this concept to become reality, it will require the field of single-molecule electronics to shift towards the semiconducting platform of the current microelectronics industry. Here, we report silicon-based single-molecule contacts that are mechanically and electrically stable under ambient conditions. The single-molecule contacts are prepared on silicon electrodes using the scanning tunnelling microscopy break-junction approach using a top metallic probe. The molecular wires show remarkable current–voltage reproducibility, as compared to an open silicon/nano-gap/metal junction, with current rectification ratios exceeding 4,000 when a low-doped silicon is used. The extension of the single-molecule junction approach to a silicon substrate contributes to the next level of miniaturization of electronic components and it is anticipated it will pave the way to a new class of robust single-molecule circuits
Electron Tunneling in Ferritin and Associated Biosystems
Ferritin is a 12 nanometer (nm) diameter iron storage protein complex that is found in most plants and animals. A substantial body of evidence has established that electrons can tunnel through and between ferritin protein nanoparticles and that it exhibits Coulomb blockade behavior, which is also seen in quantum dots and nanoparticles. This evidence can be used to understand the behavior of these particles for use in nanoelectronic devices, for biomedical applications and for investigation of quantum biological phenomena. Ferritin also has magnetic properties that make it useful for applications such as memristors and as a contrast agent for magnetic resonance imaging. This article provides a short overview of this evidence, as well as evidence of ferritin structures in vivo and of tunneling in those structures, with an emphasis on ferritin structures in substantia nigra pars compacta (SNc) neurons. Potential biomedical applications that could utilize these ferritin protein nanoparticles are also discussed.</p
Numerical investigations of temperature distribution in an AMTEC test cell and comparison with experimental data
The origin of the Acheulean: the 1.7 million-year-old site of FLK West, Olduvai Gorge (Tanzania)
The appearance of the Acheulean is one of the hallmarks of human evolution. It represents the
emergence of a complex behavior, expressed in the recurrent manufacture of large-sized tools, with
standardized forms, implying more advance forethought and planning by hominins than those required
by the precedent Oldowan technology. The earliest known evidence of this technology dates back to
c. 1.7 Ma. and is limited to two sites (Kokiselei [Kenya] and Konso [Ethiopia]), both of which lack fauna.
The functionality of these earliest Acheulean assemblages remains unknown. Here we present the
discovery of another early Acheulean site also dating to c. 1.7 Ma from Olduvai Gorge. This site provides
evidence of the earliest steps in developing the Acheulean technology and is the oldest Acheulean site in
which stone tools occur spatially and functionally associated with the exploitation of fauna. Simple and
elaborate large-cutting tools (LCT) and handaxes co-exist at FLK West, showing that complex cognition
was present from the earliest stages of the Acheulean. Here we provide a detailed technological study
and evidence of the use of these tools on the butchery and consumption of fauna, probably by early
Homo erectus sensu lato
Aircraft vertical profiles during summertime regional and Saharan dust scenarios over the north-western Mediterranean basin: aerosol optical and physical properties
We acknowledge support of the publication fee by the CSIC
Open Access Publication Support Initiative through its Unit of
Information Resources for Research (URICI).This research has been supported by the Generalitat de Catalunya, Agencia de Gestio d'Ajuts Universitaris i de Recerca (grant nos. AGAUR 2014 SGR33 and AGAUR 2017 SGR41); the Ministerio de Economia, Industria y Competitividad, Gobierno de Espana (HOUSE; grant no. CGL2016-78594-R); and the European Commission's Horizon 2020 Framework Programme (ACTRIS-2; grant no. 654109).Accurate measurements of the horizontal and vertical distribution of atmospheric aerosol particle optical properties are key for a better understanding of their impact on the climate. Here we present the results of a measurement campaign based on instrumented flights over north-eastern Spain. We measured vertical profiles of size-segregated atmospheric particulate matter (PM) mass concentrations and multi-wavelength scattering and absorption coefficients in the western Mediterranean basin (WMB). The campaign took place during typical summer conditions, characterized by the development of a vertical multi-layer structure, under both summer regional pollution episodes (REGs) and Saharan dust events (SDEs). REG patterns in the region form under high insolation and scarce precipitation in summer, favouring layering of highly aged fine-PM strata in the lower few kma.s.l.
The REG scenario prevailed during the entire measurement campaign. Additionally, African dust outbreaks and plumes from northern African wildfires influenced the study area. The vertical profiles of climate-relevant intensive optical parameters such as single-scattering albedo (SSA); the asymmetry parameter (g); scattering, absorption and SSA Ångström exponents (SAE, AAE and SSAAE); and PM mass scattering and absorption cross sections (MSC and MAC) were derived from the measurements. Moreover, we compared the aircraft measurements with those performed at two GAW–ACTRIS (Global Atmosphere Watch–Aerosol, Clouds and Trace Gases) surface measurement stations located in north-eastern Spain, namely Montseny (MSY; regional background) and Montsec d'Ares (MSA; remote site).
Airborne in situ measurements and ceilometer ground-based remote measurements identified aerosol air masses at altitudes up to more than 3.5 kma.s.l.
The vertical profiles of the optical properties markedly changed according to the prevailing atmospheric scenarios. During SDE the SAE was low along the profiles, reaching values 2.0, and the asymmetry parameter g was rather low (0.5–0.6) due to the prevalence of fine PM, which was characterized by an AAE close to 1.0, suggesting a fossil fuel combustion origin. During REG, some of the layers featured larger AAE (> 1.5), relatively low SSA at 525 nm ( 9 m2 g−1) and were associated with the influence of PM from wildfires. Overall, the SSA and MSC near the ground ranged around 0.85 and 3 m2 g−1, respectively, and increased at higher altitudes, reaching values above 0.95 and up to 9 m2 g−1. The PM, MSC and MAC were on average larger during REG compared to SDE due to the larger scattering and absorption efficiency of fine PM compared with dust. The SSA and MSC had quite similar vertical profiles and often both increased with height indicating the progressive shift toward PM with a larger scattering efficiency with altitude.
This study contributes to our understanding of regional-aerosol vertical distribution and optical properties in the WMB, and the results will be useful for improving future climate projections and remote sensing or satellite retrieval algorithms.Generalitat de Catalunya, Agencia de Gestio d'Ajuts Universitaris i de Recerca
AGAUR 2014 SGR33
AGAUR 2017 SGR41Ministerio de Economia, Industria y Competitividad, Gobierno de Espana (HOUSE)
CGL2016-78594-REuropean Commission's Horizon 2020 Framework Programme (ACTRIS-2)
65410
P-Glycoprotein and Breast Cancer Resistance Protein in Canine Inflammatory and Noninflammatory Grade III Mammary Carcinomas
P-glycoprotein (P-gp/ABCB1) and breast cancer resistance protein (BCRP/ABCG2) expression are frequently related to multidrug resistance (MDR) in neoplastic cells. Canine inflammatory and grade III noninflammatory mammary carcinomas (IMC and non-IMC) are aggressive tumors that could benefit from chemotherapy. This study describes the immunohistochemical detection of P-gp and BCRP in 20 IMCs and 18 non-IMCs from dogs that had not received chemotherapy. Our aim was to determine if P-gp and BCRP expression was related to the \u201cinflammatory\u201d phenotype, to establish a basis for future studies analyzing the response to chemotherapy in dogs with highly malignant mammary cancer. Immunolabeling was primarily membranous for P-gp with a more intense labeling in emboli, and immunolabeling was membranous and cytoplasmic for BCRP. P-gp was expressed in 17 of 20 (85%) IMCs compared to 7 of 18 (39%) non-IMCs (P = 0.006). BCRP was expressed within emboli in 15 of 19 (79%) emboli in IMC, 12 of 15 (80%) primary IMCs, and 12 of 18 (67%) non-IMCs, without statistically significant differences (P >.05). All IMCs and 67% of non-IMCs expressed at least 1 of the 2 transporters, and 63% (12/19) of IMCs and 39% (7/18) of non-IMCs expressed both P-gp and BCRP. P-gp and BCRP evaluation might help select patients for chemotherapy. P-gp, expressed in a significantly higher percentage of IMCs vs non-IMCs, might play a specific role in the chemoresistance of IMC
Towards a formal description of the collapse approach to the inflationary origin of the seeds of cosmic structure
Inflation plays a central role in our current understanding of the universe.
According to the standard viewpoint, the homogeneous and isotropic mode of the
inflaton field drove an early phase of nearly exponential expansion of the
universe, while the quantum fluctuations (uncertainties) of the other modes
gave rise to the seeds of cosmic structure. However, if we accept that the
accelerated expansion led the universe into an essentially homogeneous and
isotropic space-time, with the state of all the matter fields in their vacuum
(except for the zero mode of the inflaton field), we can not escape the
conclusion that the state of the universe as a whole would remain always
homogeneous and isotropic. It was recently proposed in [A. Perez, H. Sahlmann
and D. Sudarsky, "On the quantum origin of the seeds of cosmic structure,"
Class. Quant. Grav. 23, 2317-2354 (2006)] that a collapse (representing physics
beyond the established paradigm, and presumably associated with a
quantum-gravity effect a la Penrose) of the state function of the inflaton
field might be the missing element, and thus would be responsible for the
emergence of the primordial inhomogeneities. Here we will discuss a formalism
that relies strongly on quantum field theory on curved space-times, and within
which we can implement a detailed description of such a process. The picture
that emerges clarifies many aspects of the problem, and is conceptually quite
transparent. Nonetheless, we will find that the results lead us to argue that
the resulting picture is not fully compatible with a purely geometric
description of space-time.Comment: 53 pages, no figures. Revision to match the published versio
Evangelical Visitor- October 2, 1911. Vol. XXV. No. 20.
Evangelical Visitor published in Harrisburg, Pa., for the exposition of true, practical piety and devoted to the spread of evangelical truths and the unity of the church. Published in the interest of the church of the Brethren in Christ on October 2, 1911. Vol. XXV. No. 20
Family History in the Iberian Peninsula during Chalcolithic and Bronze Age: An Interpretation through the Genetic Analysis of Plural Burials
Throughout history, it has been observed that human populations have buried the deceased members of their communities following different patterns. During the Copper Age and the Bronze Age-periods on which this study focuses-in the northern sub-plateau of the Iberian Peninsula, we identified different patterns of multiple or collective burial. This work analyzes a total of 58 individuals buried in different multiple or collective graves, to investigate whether the practice of these burials implies a family or biological link between individuals buried together. With this aim, STR markers of nuclear DNA were analyzed, as well as the hypervariable regions I and II of mitochondrial DNA, establishing both close kinship relationships and relationships through maternal lineage. We observed different burial patterns, detecting certain maternal lines preserved in some common burials maintained over time. Close family relationships were observed to a lesser extent, with some occasional exceptions. The results of the analysis formed the basis for a discussion on the concepts of family and community
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