112 research outputs found
Visions of Global Electronic Mastery
Este texto es una de las últimas aportaciones del pionero de la Economía Política de la Comunicación Herbert I. Schiller. El él mantiene una de sus líneas de investigación fundamentales: la extensión de la doctrina del libre flujo de la información como parte de la política exterior estadounidense. Sólo que en este caso se aplica al comercio electrónico y la era digital. En este sentido uno de lo documentos analizados en profundidad por el autor, The Framework for Global Electronic Comerce, representa la actualización de la doctrina. De esta manera el mantenimiento de la hegemonía de Estados Unidos y su supremacía electrónica global serán posibles a lo largo del siglo XXI.This text is one of the last contributions of pioneer of Political Economy of Communication Herbert I. Schiller. The author keeps up with one of his fundamental thesis, that is, the extension of the free flow of information doctrine as part of the US foreign policy. In this case it is applied to electronic commerce and the digital era. In this sense one of the documents analysed in depth by the author, The Framework for Electronic Commerce, represents the actualization of this doctrine. Thus the preservation of US hegemony and its global electronic mastery will be a fact along the 21st century
Augurios de supremacía electrónica global
Este texto es una de las últimas aportaciones del pionero de la Economía Política de la Comunicación Herbert I. Schiller. El él mantiene una de sus líneas de investigación fundamentales: la extensión de la doctrina del libre flujo de la información como parte de la política exterior estadounidense. Sólo que en este caso se aplica al comercio electrónico y la era digital. En este sentido uno de lo documentos analizados en profundidad por el autor, The Framework for Global Electronic Comerce, representa la actualización de la doctrina. De esta manera el mantenimiento de la hegemonía de Estados Unidos y su supremacía electrónica global serán posibles a lo largo del siglo XXI
Highly resolved observations of trace gases in the lowermost stratosphere and upper troposphere from the Spurt project: an overview
During SPURT (Spurenstofftransport in der Tropopausenregion, trace gas transport in the tropopause region) we performed measurements of a wide range of trace gases with different lifetimes and sink/source characteristics in the northern hemispheric upper troposphere (UT) and lowermost stratosphere (LMS). A large number of in-situ instruments were deployed on board a Learjet 35A, flying at altitudes up to 13.7 km, at times reaching to nearly 380 K potential temperature. Eight measurement campaigns (consisting of a total of 36 flights), distributed over all seasons and typically covering latitudes between 35° N and 75° N in the European longitude sector (10° W–20° E), were performed. Here we present an overview of the project, describing the instrumentation, the encountered meteorological situations during the campaigns and the data set available from SPURT. Measurements were obtained for N2O, CH4, CO, CO2, CFC12, H2, SF6, NO, NOy, O3 and H2O. We illustrate the strength of this new data set by showing mean distributions of the mixing ratios of selected trace gases, using a potential temperature – equivalent latitude coordinate system. The observations reveal that the LMS is most stratospheric in character during spring, with the highest mixing ratios of O3 and NOy and the lowest mixing ratios of N2O and SF6. The lowest mixing ratios of NOy and O3 are observed during autumn, together with the highest mixing ratios of N2O and SF6 indicating a strong tropospheric influence. For H2O, however, the maximum concentrations in the LMS are found during summer, suggesting unique (temperature- and convection-controlled) conditions for this molecule during transport across the tropopause. The SPURT data set is presently the most accurate and complete data set for many trace species in the LMS, and its main value is the simultaneous measurement of a suite of trace gases having different lifetimes and physical-chemical histories. It is thus very well suited for studies of atmospheric transport, for model validation, and for investigations of seasonal changes in the UT/LMS, as demonstrated in accompanying and elsewhere published studies
On the Possibility of Measuring the Gravitomagnetic Clock Effect in an Earth Space-Based Experiment
In this paper the effect of the post-Newtonian gravitomagnetic force on the
mean longitudes of a pair of counter-rotating Earth artificial satellites
following almost identical circular equatorial orbits is investigated. The
possibility of measuring it is examined. The observable is the difference of
the times required to in passing from 0 to 2 for both senses of
motion. Such gravitomagnetic time shift, which is independent of the orbital
parameters of the satellites, amounts to 5 s for Earth; it is
cumulative and should be measured after a sufficiently high number of
revolutions. The major limiting factors are the unavoidable imperfect
cancellation of the Keplerian periods, which yields a constraint of 10
cm in knowing the difference between the semimajor axes of the satellites,
and the difference of the inclinations of the orbital planes which, for
, should be less than . A pair of spacecrafts
endowed with a sophisticated intersatellite tracking apparatus and drag-free
control down to 10 cm s Hz level might allow to meet
the stringent requirements posed by such a mission.Comment: LaTex2e, 22 pages, no tables, 1 figure, 38 references. Final version
accepted for publication in Classical and Quantum Gravit
Nonlinear adiabatic response of interacting quantum dots
We develop a generic method in Liouville space to describe the dissipative
dynamics of coherent interacting quantum dots with adiabatic time dependence
beyond linear response. We show how the adiabatic response can be related to
effective quantities known from real-time renormalization group methods for
stationary quantities. We propose the study of a generalized -time as a
characteristic time scale. We apply the method to the interacting resonant
level model and calculate the nonlinear adiabatic charge response to
time-dependent gate voltages, tunneling barriers and Coulomb interaction. The
generalized -time is found to acquire a unique form in all cases, in
contrast to the capacitance and the charge relaxation resistance. We discuss
the observability of the effects in molecular systems and cold atom setups.Comment: 6 page
Single-cell RNA sequencing reveals ex vivo signatures of SARS-CoV-2-reactive T cells through ‘reverse phenotyping’
Abstract
The in vivo phenotypic profile of T cells reactive to severe acute respiratory syndrome (SARS)-CoV-2 antigens remains poorly understood. Conventional methods to detect antigen-reactive T cells require in vitro antigenic re-stimulation or highly individualized peptide-human leukocyte antigen (pHLA) multimers. Here, we use single-cell RNA sequencing to identify and profile SARS-CoV-2-reactive T cells from Coronavirus Disease 2019 (COVID-19) patients. To do so, we induce transcriptional shifts by antigenic stimulation in vitro and take advantage of natural T cell receptor (TCR) sequences of clonally expanded T cells as barcodes for ‘reverse phenotyping’. This allows identification of SARS-CoV-2-reactive TCRs and reveals phenotypic effects introduced by antigen-specific stimulation. We characterize transcriptional signatures of currently and previously activated SARS-CoV-2-reactive T cells, and show correspondence with phenotypes of T cells from the respiratory tract of patients with severe disease in the presence or absence of virus in independent cohorts. Reverse phenotyping is a powerful tool to provide an integrated insight into cellular states of SARS-CoV-2-reactive T cells across tissues and activation states
An integrated cell atlas of the lung in health and disease
Single-cell technologies have transformed our understanding of human tissues. Yet, studies typically capture only a limited number of donors and disagree on cell type definitions. Integrating many single-cell datasets can address these limitations of individual studies and capture the variability present in the population. Here we present the integrated Human Lung Cell Atlas (HLCA), combining 49 datasets of the human respiratory system into a single atlas spanning over 2.4 million cells from 486 individuals. The HLCA presents a consensus cell type re-annotation with matching marker genes, including annotations of rare and previously undescribed cell types. Leveraging the number and diversity of individuals in the HLCA, we identify gene modules that are associated with demographic covariates such as age, sex and body mass index, as well as gene modules changing expression along the proximal-to-distal axis of the bronchial tree. Mapping new data to the HLCA enables rapid data annotation and interpretation. Using the HLCA as a reference for the study of disease, we identify shared cell states across multiple lung diseases, including SPP
An integrated cell atlas of the lung in health and disease
Single-cell technologies have transformed our understanding of human tissues. Yet, studies typically capture only a limited number of donors and disagree on cell type definitions. Integrating many single-cell datasets can address these limitations of individual studies and capture the variability present in the population. Here we present the integrated Human Lung Cell Atlas (HLCA), combining 49 datasets of the human respiratory system into a single atlas spanning over 2.4 million cells from 486 individuals. The HLCA presents a consensus cell type re-annotation with matching marker genes, including annotations of rare and previously undescribed cell types. Leveraging the number and diversity of individuals in the HLCA, we identify gene modules that are associated with demographic covariates such as age, sex and body mass index, as well as gene modules changing expression along the proximal-to-distal axis of the bronchial tree. Mapping new data to the HLCA enables rapid data annotation and interpretation. Using the HLCA as a reference for the study of disease, we identify shared cell states across multiple lung diseases, including SPP1+ profibrotic monocyte-derived macrophages in COVID-19, pulmonary fibrosis and lung carcinoma. Overall, the HLCA serves as an example for the development and use of large-scale, cross-dataset organ atlases within the Human Cell Atlas
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