1,545 research outputs found
Assessing satellite-derived land product quality for earth system science applications: results from the ceos lpv sub-group
The value of satellite derived land products for science applications and research is dependent upon the known accuracy of the data. CEOS (Committee on Earth Observation Satellites), the space arm of the Group on Earth Observations (GEO), plays a key role in coordinating the land product validation process. The Land Product Validation (LPV) sub-group of the CEOS Working Group on Calibration and Validation (WGCV) aims to address the challenges associated with the validation of global land products. This paper provides an overview of LPV sub-group focus area activities, which cover seven terrestrial Essential Climate Variables (ECVs). The contribution will enhance coordination of the scientific needs of the Earth system communities with global LPV activities
Peatlands and the carbon cycle: from local processes to global implications - a synthesis
Peatlands cover only 3% of the Earth's land surface but boreal and subarctic peatlands store about 15-30% of the world's soil carbon ( C) as peat. Despite their potential for large positive feedbacks to the climate system through sequestration and emission of greenhouse gases, peatlands are not explicitly included in global climate models and therefore in predictions of future climate change. In April 2007 a symposium was held in Wageningen, the Netherlands, to advance our understanding of peatland C cycling. This paper synthesizes the main findings of the symposium, focusing on (i) small-scale processes, (ii) C fluxes at the landscape scale, and (iii) peatlands in the context of climate change. The main drivers controlling most are related to some aspects of hydrology. Despite high spatial and annual variability in Net Ecosystem Exchange ( NEE), the differences in cumulative annual NEE are more a function of broad scale geographic location and physical setting than internal factors, suggesting the existence of strong feedbacks. In contrast, trace gas emissions seem mainly controlled by local factors. Key uncertainties remain concerning the existence of perturbation thresholds, the relative strengths of the CO2 and CH4 feedback, the links among peatland surface climate, hydrology, ecosystem structure and function, and trace gas biogeochemistry as well as the similarity of process rates across peatland types and climatic zones. Progress on these research areas can only be realized by stronger co-operation between disciplines that address different spatial and temporal scales
Measurement of the B semileptonic branching fraction into excited charm mesons
The territorial dialogue reveals to be, indeed, a process of stake in common of objectives which the group in charge of the territorial organization should share or in any cases which he should make his. Whereas a joint territorial policy can be the actual result of this reflection and opens the actors in a territorial coordination. This coordination is a process rationalizing of vision of the world which applies to the territory. This process collects the actors and transforms them into a collective actor: the practice of the territorial watch participates of this territorial policy joint and introduced in upstream. The territorial dialogue is so preliminary, possibly , in a joint territorial policy. It has for goal to come to an agreement on a territorial vision, and on an explicit gratitude(recognition) of the legitimacy of the actors having power to act on this vision. The recognition and so, the nearness, obtains by a link of the vision which hold the actors
Neural Collaborative Filtering
In recent years, deep neural networks have yielded immense success on speech
recognition, computer vision and natural language processing. However, the
exploration of deep neural networks on recommender systems has received
relatively less scrutiny. In this work, we strive to develop techniques based
on neural networks to tackle the key problem in recommendation -- collaborative
filtering -- on the basis of implicit feedback. Although some recent work has
employed deep learning for recommendation, they primarily used it to model
auxiliary information, such as textual descriptions of items and acoustic
features of musics. When it comes to model the key factor in collaborative
filtering -- the interaction between user and item features, they still
resorted to matrix factorization and applied an inner product on the latent
features of users and items. By replacing the inner product with a neural
architecture that can learn an arbitrary function from data, we present a
general framework named NCF, short for Neural network-based Collaborative
Filtering. NCF is generic and can express and generalize matrix factorization
under its framework. To supercharge NCF modelling with non-linearities, we
propose to leverage a multi-layer perceptron to learn the user-item interaction
function. Extensive experiments on two real-world datasets show significant
improvements of our proposed NCF framework over the state-of-the-art methods.
Empirical evidence shows that using deeper layers of neural networks offers
better recommendation performance.Comment: 10 pages, 7 figure
Semantic Web Data Discovery of Earth Science Data at NASA Goddard Earth Sciences Data and Information Services Center (GES DISC)
Mirador is a web interface for searching Earth Science data archived at the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC). Mirador provides keyword-based search and guided navigation for providing efficient search and access to Earth Science data. Mirador employs the power of Google's universal search technology for fast metadata keyword searches, augmented by additional capabilities such as event searches (e.g., hurricanes), searches based on location gazetteer, and data services like format converters and data sub-setters. The objective of guided data navigation is to present users with multiple guided navigation in Mirador is an ontology based on the Global Change Master directory (GCMD) Directory Interchange Format (DIF). Current implementation includes the project ontology covering various instruments and model data. Additional capabilities in the pipeline include Earth Science parameter and applications ontologies
Finding Atmospheric Composition (AC) Metadata
The Atmospheric Composition Portal (ACP) is an aggregator and curator of information related to remotely sensed atmospheric composition data and analysis. It uses existing tools and technologies and, where needed, enhances those capabilities to provide interoperable access, tools, and contextual guidance for scientists and value-adding organizations using remotely sensed atmospheric composition data. The initial focus is on Essential Climate Variables identified by the Global Climate Observing System CH4, CO, CO2, NO2, O3, SO2 and aerosols. This poster addresses our efforts in building the ACP Data Table, an interface to help discover and understand remotely sensed data that are related to atmospheric composition science and applications. We harvested GCMD, CWIC, GEOSS metadata catalogs using machine to machine technologies - OpenSearch, Web Services. We also manually investigated the plethora of CEOS data providers portals and other catalogs where that data might be aggregated. This poster is our experience of the excellence, variety, and challenges we encountered.Conclusions:1.The significant benefits that the major catalogs provide are their machine to machine tools like OpenSearch and Web Services rather than any GUI usability improvements due to the large amount of data in their catalog.2.There is a trend at the large catalogs towards simulating small data provider portals through advanced services. 3.Populating metadata catalogs using ISO19115 is too complex for users to do in a consistent way, difficult to parse visually or with XML libraries, and too complex for Java XML binders like CASTOR.4.The ability to search for Ids first and then for data (GCMD and ECHO) is better for machine to machine operations rather than the timeouts experienced when returning the entire metadata entry at once. 5.Metadata harvest and export activities between the major catalogs has led to a significant amount of duplication. (This is currently being addressed) 6.Most (if not all) Earth science atmospheric composition data providers store a reference to their data at GCMD
Cross-Cultural Counseling: Bridge Between Desegregation and Integration. A Study Relative to Group Counseling and its Impact on Students and Faculty
For the past several years; much emphasis has been placed on open enrollment plans involving bussing that enable black and white students to attend schools together. The Laboratory School of the University of Northern Iowa in Cedar Falls has been involved in such a program since 1968. As the project developed; the potential for very serious problems relating to racial tension and student frustration became evident. To approach these problems and to promote more openness and understanding between students from different communities and differing cultural backgrounds; cross-cultural group counseling sessions were developed. The groups during the past two years have consisted of combined 7th and 8th graders and combined 9th through 12th graders. Due to administrative support; student requests; and observed behavior change; a similar grouping of students will be employed during the 1972-73 academic year. Counselor observations of the program are examined; and student and faculty questionnaires and analyses of them are also included in this paper. (Author
A Study of Cross-Cultural Groups at Malcolm Price Laboratory School; University of Northern Iowa
A brief history of the integration efforts of the school and the resulting interracial conflict is presented. From this background evolved the cross-cultural groups which are the focus of this paper. Essentially; discussion was used for exploring the issues which were identified as impediments to good relationships within the school; (1) too few black faculty and students; (2) the impact of Tomism; (3) geographic location of students\u27 homes; (4) differing interests of black and white students; (5) the need for extra-school interracial contact; and (6) inhibitions; both social and parental; against interracial contact; especially dating. The results of a questionnaire; administered to 51 black and white students in the school; suggests the impact of the cross-cultural groups. While a number of negative aspects are revealed in the data; the authors focus on two positives: (1) the overwhelming enthusiasm of students to continue participating in the groups; and (2) principal and staff perceptions of an improved school environment. (TL
Shared as well as distinct roles of EHD proteins revealed by biochemical and functional comparisons in mammalian cells and C. elegans
BACKGROUND: The four highly homologous human EHD proteins (EHD1-4) form a distinct subfamily of the Eps15 homology domain-containing protein family and are thought to regulate endocytic recycling. Certain members of this family have been studied in different cellular contexts; however, a lack of concurrent analyses of all four proteins has impeded an appreciation of their redundant versus distinct functions. RESULTS: Here, we analyzed the four EHD proteins both in mammalian cells and in a cross-species complementation assay using a C. elegans mutant lacking the EHD ortholog RME-1. We show that all human EHD proteins rescue the vacuolated intestinal phenotype of C. elegans rme-1 mutant, are simultaneously expressed in a panel of mammalian cell lines and tissues tested, and variably homo- and hetero-oligomerize and colocalize with each other and Rab11, a recycling endosome marker. Small interfering RNA (siRNA) knock-down of EHD1, 2 and 4, and expression of dominant-negative EH domain deletion mutants showed that loss of EHD1 and 3 (and to a lesser extent EHD4) but not EHD2 function retarded transferrin exit from the endocytic recycling compartment. EH domain deletion mutants of EHD1 and 3 but not 2 or 4, induced a striking perinuclear clustering of co-transfected Rab11. Knock-down analyses indicated that EHD1 and 2 regulate the exit of cargo from the recycling endosome while EHD4, similar to that reported for EHD3 (Naslavsky et al. (2006) Mol. Biol. Cell 17, 163), regulates transport from the early endosome to the recycling endosome. CONCLUSION: Altogether, our studies suggest that concurrently expressed human EHD proteins perform shared as well as discrete functions in the endocytic recycling pathway and lay a foundation for future studies to identify and characterize the molecular pathways involved
Recommended from our members
Comparison of the seasonal and interannual variability of phytoplankton pigment concentrations in the Peru and California Current systems
Monthly composite images from the global coastal zone color scanner
(CZCS) data set are used to provide an initial illustration and comparison of seasonal
and interannual variability of phytoplankton pigment concentration along the western
coasts of South and North America in the Peru Current system (PCS) and California
Current system (CCS). The analysis utilizes the entire time series of available data
(November 1978 to June 1986) to form a mean annual cycle and an index of interannual
variability for a series of both latitudinal and cross-shelf regions within each current
system. Within 100 km of the coast, the strongest seasonal cycles in the CCS are in
two regions, one between 34° and 45°N and the second between 24° and 29°N, each
with maximum concentrations (>3.0 mg m⁻³) in MayJune. Weaker seasonal
variability is present north of 45°N and in the Southern California Bight region (32°N).
Within the PCS, in the same 100-km-wide coastal region, highest (>45°S) and lowest
(<20°S) latitude regions have a similar seasonal cycle with maximum concentrations
(> 1.5 mg m⁻³) during the austral spring, summer, and fall, matching that evident
throughout the CCS. Between these regions, off northern and central Chile, the
seasonal maximum occurs during JulyAugust (austral winter), contrary to the
influence of upwelling favorable winds. Within the CCS, the dominant feature of
interannual variability in the 8-year time series is a strong negative concentration
anomaly in 1983, an El Nino year. The relative value of this negative anomaly is
strongest off central California and is followed by an even stronger negative anomaly in
1984 off Baja California. In the PCS, strong negative anomalies during the 1982-1983 El
Nino period are evident only off the Peruvian coast and are evident there only in the
regions 100 km or more from the coast. Although negative anomalies associated with
the El Nino were not present at higher latitudes (more than approximately 20°S) in the
PCS, the extremely sparse sampling weakens our confidence in the results of the
interannual analysis in this region. An upper estimate of the systematic winter bias
remaining in the global CZCS data after reprocessing with the multiple scattering
algorithm is given in the appendix.Copyright 1994 by the American Geophysical Union
- …