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Impact of dietary fat on the development of non-alcoholic fatty liver disease in Ldlr−/− mice
No full textThe prevalence of non-alcoholic fatty liver disease (NAFLD) has increased in parallel with central obesity and is now the most common chronic liver disease in developed countries. NAFLD is defined as excessive accumulation of lipid in the liver, i.e., hepatosteatosis. The severity of NAFLD ranges from simple fatty liver (steatosis) to non-alcoholic steatohepatitis (NASH). Simple steatosis is relatively benign until it progresses to NASH, which is characterized by hepatic injury, inflammation, oxidative stress and fibrosis. Hepatic fibrosis is a risk factor for cirrhosis and primary hepatocellular carcinoma (HCC). Our studies have focused on the impact of diet on the onset and progression of NASH. We developed a mouse model of NASH by feeding Ldlr-/- mice a “western diet” (WD); a diet moderately high in saturated and trans-fat, sucrose and cholesterol. The WD induced a NASH phenotype in Ldlr-/- mice that recapitulates many of the clinical features of human NASH. We also assessed the capacity of the dietary ω3-polyunsaturated fatty acids (ω3-PUFA), i.e., eicosapentaenoic acid (EPA, 20:5,ω3) and docosahexaenoic acid (DHA, 22:6,ω3), to prevent WD-induced NASH in Ldlr-/- mice. Histologic, transcriptomic, lipidomic and metabolomic analyses established that DHA was equal or superior to EPA at attenuating WD-induced dyslipidemia and hepatic injury, inflammation, oxidative stress and fibrosis. Dietary ω3-PUFA, however, had no significant effect on WD-induced changes in body weight, body fat or blood glucose. These studies provide a molecular and metabolic basis for understanding the strengths and weaknesses of using dietary ω3 PUFA to prevent NASH in humans.This is an author's peer-reviewed final manuscript, as accepted by the publisher. The article is copyrighted by the Authors and published by Cambridge University Press. It can be found at: http://journals.cambridge.org/action/displayJournal?jid=PNSKeywords: Non-alcoholic steatohepatitis, ω3-PUFA, Oxidative stress, Fibrosis, Inflammation, n-3 PUF
The effect of climate variation on agro-pastoral production in Africa
Get PDFUsing national crop and livestock production records from 1961–2003 and satellite-derived data on pasture greenness from 1982–2003 we show that the productivity of crops, livestock, and pastures in Africa is predictably associated with the El Niño Southern Oscillation and the North Atlantic Oscillation. The causal relations of these results are partly understandable through the associations between the atmospheric fluctuations and African rainfall. The range of the explained among-year variation in crop production in Africa as a whole corresponds to the nutritional requirements for ≈20 million people. Results suggest reduced African food production if the global climate changes toward more El Niño-like conditions, as most climate models predict. Maize production in southern Africa is most strongly affected by El Niño events. Management measures include annual changes in crop selection and storage strategies in response to El Niño Southern Oscillation-based and North Atlantic Oscillation-based predictions for the next growing season.Keywords: nonlinear statistical modelling, food production, North Atlantic Oscillation, Normalized Difference Vegetation Index, El Nino Southern Oscillatio
Strain distribution and load transfer in the polymer-wood particle bond in wood plastic composites
Get PDFThe load transfer between wood particles and the matrix was analyzed by observation of the strain patterns in thin films of high density polyethylene (HDPE) with embedded wood particles subjected to tensile loading. Optical measurement techniques based on the digital image correlation (DIC) principle were employed for quantitative measurement of strain distributions on the surfaces of the specimens. Interpretation of these measurements in terms of load transfer between the particle and the matrix below the surface proved challenging and required a structured approach. In this paper, quantitative descriptors were selected as synthesized metrics to support the quantitative interpretation of the measured strains. X-ray computed tomography (XCT) scans were used to assess the effect of the position of the particles in the film specimens on the strains patterns observed on the surface.This is the publisher’s final pdf. The published article is copyrighted by Walter de Gruyter GmbH and can be found at: http://www.degruyter.com/view/j/hfsg.Keywords: optical measurement, wood plastic composites, micromechanics, digital image correlation, short fiber composites theory, load transfe
An approach to designing a national climate service
Get PDFClimate variability and change are considerably important for a wide range of human activities and natural ecosystems. Climate science has made major advances during the last two decades, yet climate information is neither routinely useful for nor used in planning. What is needed is a mechanism, a national climate service (NCS), to connect climate science to decision-relevant questions and support building capacity to anticipate, plan for, and adapt to climate fluctuations. This article contributes to the national debate for an NCS by describing the rationale for building an NCS, the functions and services it would provide, and how it should be designed and evaluated. The NCS is most effectively achieved as a federal interagency partnership with critically important participation by regional climate centers, state climatologists, the emerging National Integrated Drought Information System, and the National Oceanic and Atmospheric Administration (NOAA) Regional Integrated Sciences Assessment (RISA) teams in a sustained relationship with a wide variety of stakeholders. Because the NCS is a service, and because evidence indicates that the regional spatial scale is most important for delivering climate services, given subnational geographical/geophysical complexity, attention is focused on lessons learned from the University of Washington Climate Impacts Group's 10 years of experience, the first of the NOAA RISA teams.Keywords: Pacific Northwest climate, regional integrated sciences and assessment
Evaluation of Network Expansion Decisions for Resilient Interdependent Critical Infrastructures with Different Topologies
Get PDFResilient interdependent critical infrastructures (CIs) can better withstand cascading failures in disruptive events. This study proposes network expansion as a resilience improvement strategy for interdependent CIs and evaluates the influence of topology in interdependent network design for resilience optimization under disruption uncertainty. A resilience score consisting of network complexity and unmet demand metrics is introduced to quantify the resilience of expanded networks. Five synthetic interdependent network instances with random and hub-and-spoke (i.e., cluster) topologies are generated to represent CIs with heterogeneous node functions. Different network expansion opportunities are considered and critical node disruption scenarios are used to evaluate the impact of uncertain disruptions. We apply a two-stage stochastic multi-objective resilience optimization model to determine strategic investment decisions using the expected total cost and expected resilience score as competing objectives. Compromise solutions of expanded network designs are identified from Pareto optimal solutions and they are characterized according to their graph properties. The results show that expanded networks have improved resilience and the extent of improvement is affected by the network topology and type of disruption. Under critical node disruptions, a random network is more resilient than a hub-and-spoke structure due to its better connectivity. Characteristics of highly connected interdependent networks are high average node degree, high clustering coefficient, and low average shortest path length. Resilience improvement is more limited in expanded networks with a hub-and-spoke structure due to the negative impact of hub failures
Persona concept : system architecture and prototypes
Get PDFThis project explores a security framework, called the Persona Concept, aimed at giving the user greater control over their private data in cyberspace, in particular, their electronic credentials. The background for the Persona Concept, along with the requirements identified can be found in three (3) technical publications produced by Kal Toth and myself in 2003 (see list of references [1], [2] and [3]).
The Persona Concept uses a Persona Server as the secure storehouse for persona data such as credit card and bank account identifiers as well electronic credentials such as X.509 certificates. The data is secured using public key encryption. The server component interacts with the user via a Persona Client which obtains X-509 Certificates on behalf of the user from a Certification Authority (CA) service. Interaction among the various components (Persona Server, Persona Client and Certification Authority) is enabled by the use of Web Services.
This project focused on managing the user data across these components including the creation, secure storage and retrieval of Persona data to and from the Persona Server using Simple Object Application Protocol (SOAP) and under the control of public key encryption schemes. SOAP is an open XML-based application-level Internet protocol for implementing distributed access to object-oriented services deployed on the Web. SOAP is designed to allow applications running on a range of platforms to access remote objects and applications on servers across a TCP/IP network. In addition to this, the project built upon the work by Ike Chen (OSU M.S. graduate project in 2004) [4] by enabling X-509 Certificate file transfer between the client and Certification Authority using SOAP (improvements were made to the mechanisms for transferring files, particularly in support of X.509 certificates). A Java-based prototype client called the Persona Client (PC) was created and used in conjunction with a small local password-based security scheme to protect the private key data on the user device.
My project first implemented the upgrade to the Certification Authority services and detailed the various policies surrounding storage of data. I then implemented the Persona Client which enabled me to test the persona services in place. I then implemented the encryption schemes and the server components enabling the secure storage and transfer of Persona Data. Components to create, edit and delete data were packaged and published as services to be used by the Persona Client.
Future extensions of this project could include exploring custom credential generation based on Security Assertion Markup Language (SAML) and Extensible Access Control Markup Language (XACML) which together can be used to specify XML-based credentials and access control policies for an enterprise. Other extensions include the implementation of discretionary and mandatory security policies using XACML to allow users to conduct transactions across various domains
Social segregation of humpback whales in contrasted coastal and oceanic breeding habitats
No full textArticle available for download at publisher's website: https://doi.org/10.1093/jmammal/gyx185Maternal habitat preferences of humpback whales (Megaptera novaeangliae) are well documented from decades of coastal research but oceanic areas have received less attention. Whales breeding in New Caledonia occupy both ecosystems: a coastal reef complex (South Lagoon) and oceanic seamounts (Southern Seamounts). Generalized additive models were applied to 20 years of boat-based whale observations (n = 1,526) to describe habitat preferences and permissive home range estimations were used to explicitly model spatial segregation in relation to social context. Groups with calves (n = 206) preferred shallow coastal waters throughout the season in the South Lagoon, whereas no habitat segregation was observed between groups with (n = 74) and without calves (n = 140) in the Southern Seamounts. As a result, spatial overlap between groups with and without calves was more common in the Southern Seamounts than the South Lagoon. Despite a lack of social segregation around seamounts, mother-calf pairs were proportionally more frequent in the Southern Seamounts (27%) than in the South Lagoon (16%). Photographs of the calves’ dorsal flanks were analyzed to compare age and ecological markers across sites. Calves appeared older in the Southern Seamounts than in the South Lagoon but no difference in scarring or shark bites was found across sites, suggesting that calves experienced similar lifestyles and may move between offshore and coastal waters during the breeding season. This study highlights the flexible habitat use patterns of breeding humpback whales and raises new questions about the environmental and social drivers of their presence in offshore breeding grounds.Key words: breeding ground, habitat use, humpback whales, Pacific Ocean, seamounts, social interaction
Benthic marine algae on Japanese tsunami marine debris – a morphological documentation of the species. Part 2 – The brown algae
Get PDFTo determine the invasion threat to the NE Pacific of marine algae arriving on Japanese debris from the 2011 Great Tōhoku Earthquake and Tsunami, my colleagues and I identified the algal species on 42 of the most heavily fouled debris items that landed on the shores of Oregon and Washington between June 2012 and July 2016. Using both morphological and molecular methods, we identified 84 marine algal and cyanobacterial species and species complexes on debris from these items and sequenced 51. Since many of these species are not well-described in the literature, a morphological account of the actual specimens has been prepared to assist in the detection of future invasions by these species in the NE Pacific. The series is divided into 3 parts: Part 1 – The tsunami event, the project overview, and the red algae, Part 2 – The brown algae, and Part 3 – The green algae and cyanobacteria. In Part 2 that follows, we provide pictures and descriptions of 30 brown algal species and 3 unknowns that we have found on debris. We also include descriptions of many of the morphological and/or genetic variants that we discovered in the following 7 species: Ectocarpus arctus, Feldmannia irregularis, Feldmannia mitchelliae, Kucuckia spinosa, Petalonia fascia, Punctaria latifolia, and Scytosiphon lomentaria. Some of these variants should be synonymized, but others appear to require re-establishment or description as new species. For additional information on all of the debris algal species, please see our related papers on the project cited on p. 2 of the text.Keywords: marine algae, North Pacific Ocean, introduced marine species, brown algae, Northeast Pacific Ocean, tsunami debri
Ocean circulation and properties in Petermann Fjord, Greenland
Get PDFThe floating ice shelf of Petermann glacier interacts directly with the ocean and is thought to lose at least 80% of its mass through basal melting. Based on three opportunistic ocean surveys in Petermann Fjord we describe the basic oceanography: the circulation at the fjord mouth, the hydrographic structure beneath the ice shelf, the oceanic heat delivered to the under‐ice cavity, and the fate of the resulting melt water. The 1100 m deep fjord is separated from neighboring Hall Basin by a sill between 350 and 450 m deep. Fjord bottom waters are renewed by episodic spillover at the sill of Atlantic water from the Arctic. Glacial melt water appears on the northeast side of the fjord at depths between 200 m and that of the glacier’s grounding line (about 500 m). The fjord circulation is fundamentally three‐dimensional; satellite imagery and geostrophic calculations suggest a cyclonic gyre within the fjord mouth, with outflow on the northeast side. Tidal flows are similar in magnitude to the geostrophic flow. The oceanic heat flux into the fjord appears more than sufficient to account for the observed rate of basal melting. Cold, low‐salinity water originating in the surface layer of Nares Strait in winter intrudes far under the ice. This may limit basal melting to the inland half of the shelf. The melt rate and long‐term stability of Petermann ice shelf may depend on regional sea ice cover and fjord geometry, in addition to the supply of oceanic heat entering the fjord.Keywords: Petermann Fjord\, Greenland, Ocean circulation propertie
Occurrence and sources of natural and anthropogenic lipid tracers in surface soils from arid urban areas of Saudi Arabia
Get PDFSoil particles contain a variety of natural and anthropogenic organic components, and in urban areas can be considered as local collectors of pollutants. Surface soil samples were taken from ten urban areas in Riyadh during early winter of 2007. They were extracted with dichloromethane-methanol mixture and the extracts were analyzed by gas chromatography-mass spectrometry. The major compounds were unresolved complex mixture (UCM), plasticizers, n-alkanes, carbohydrates, n-alkanoic acids, hopanes, n-alkanols, and sterols. Vegetation detritus was the major natural source of organic compounds (24.0 ± 15.7%) in samples from areas with less human activities and included n-alkanes, n-alkanoic acids, n-alkanols, sterols and carbohydrates. Vehicular emission products and discarded plastics were the major anthropogenic sources in the soil particles (53.3 ± 21.3% and 22.7 ± 10.7%, respectively). The anthropogenic tracers were UCM, plasticizers, n-alkanes, hopanes and traces of steranes. Vegetation and human activities control the occurrence and distribution of natural and anthropogenic extractable organic matter in this arid urban area.Keywords: Petroleum residues, Biomarkers, Soils, Lipids, Plasticizer