North American Network Research Articles

How different regional approaches to the network design result in key differences in burst event severity and failure vulnerability

Abstract The pipe burst response of an innovative Dutch water distribution network is compared to a traditional looped North American network. Dutch networks focus on water quality and use smaller diameter pipes in branches. The branched network discharges much less water after a burst, which may reduce local flooding, traffic disruption, and product loss. In addition, high velocities and transient pressures are shown to be much localized in the branched Dutch network after a burst, reducing the risks associated with the intrusion of contaminants. However, despite improved water quality, less water loss, and more localized transients, the branched network cannot meet water demands downstream of the burst until the pipe is repaired, unlike a traditional looped network. For modern buildings that meet current design guidelines, the Dutch are content with much lower fire-flow requirements that provide the flexibility to improve water quality and reduce the consequences of pipe bursts, especially water loss.

Dendroclimatology of Yellow-Cedar (Callitropsis nootkatensis) and Temperature Variability on the Western Slopes of the North Cascades in Washington State, USA, from 1333 to 2015 CE

Long-term paleoclimate reconstructions of temperature provide context for the magnitude of recent anthropogenic warming, help quantify the climate response to radiative forcing, and better characterize the range of natural variability. In North America, temperature-sensitive tree-ring proxy data remain sparse, which limits the spatial and temporal extent of these reconstructions. Here we present an analysis of yellow-cedar (Callitropsis nootkatensis) growth in Washington State (USA) and its relationship to climate. Combining empirical statistical analysis with a process model of xylogenesis, we show that tree-ring chronologies from three high-elevation sites in the North Cascades are primarily controlled by temperature. We then use these chronologies to reconstruct summer temperatures over the period 1333 to 2015 CE, adding a new proxy to the North American network of temperature-sensitive trees. Comparison with an existing large-scale spatial gridded reconstruction suggests this species offers important local and regional information on past temperatures.

Evaluating national electric grid reliability by 2030 using the Barabási-Albert network model

This study focuses on the development of a new probabilistic approach for reliability study it consists of studying the reliability of one of the North Africa electric grid, in order to propose an adequate production plan for 2030. A production plan where renewable energies take a large place in the production park, our objective is the planning and optimization of the energy system with a strong integration of renewable energy sources by guaranteeing the reliability of the electricity system in order to succeed in the energy transition. The reliability of a power system is a measure of its ability to supply the required electricity to its various points of use within acceptable standards. Indeed, the primary function of an electrical network is to provide reliable and economical power to its customers. However, the integration of renewables into the electricity grid leads to a change in the behavior of the electricity grid with respect to the satisfaction of electricity demand. Thus, in this article, we have evaluated the reliability of the electricity network in the presence of renewables energies based on probabilistic approaches more precisely the model of the Barabási-Albert network using Scale-free network. The model of Barabási Albert was applied for the first time on the electrical networks the case of the North American network and it gave good results if we compare it with the other usual methods that we decided to apply it on the Moroccan grid we compare the results.

Changing the Lab Experience: Using Technology to Deliver Science Instruction in Rural Communities

AbstractThis case study of an online science laboratory network, the North American Network of Science Labs Online (NANSLO), demonstrates that successful initiatives must fit well within institutions’ existing structural and programmatic elements as well as align with institutional goals, course‐level programming, and have adequate buy‐in at the faculty level.

Performance analysis of novel routing and spectrum allocation algorithm in elastic optical networks

With the rapid development of services such as mobile Internet, high-definition video, and cloud computing, users' bandwidth requirements are increasing, and the demand for bandwidth granularity is becoming more diverse. In order to solve this problem, the researchers proposed the concept of elastic optical networks. The Elastic optical network adopts the flexible grid transmission mode, which can flexibly allocate spectrum resources while meeting high bandwidth and diversity requirements. Considering the modulation, routing and spectrum allocation (RMSA) of modulation mode selection on different paths is an extremely important problem in elastic optical networks. This paper presents a RMSA algorithm for Elastic Optical Networks with a Tradeoff between consumed resources and interval with boundary (Tradeoff-RnI). For a connection, the amount of resources consumed (R) and the interval between the spectrum blocks and the boundary (I) are indicators that need to be minimized. For these two indicators, the RMSA problem is first modeled as a multi-objective optimization model, and then a linear combination αR+ (1-α) I of R and I is designed. The target RMSA algorithm takes a compromise between R and I. Simulation and comparative analysis of the Tradeoff-RnI algorithm in 24-node US network (UNB24) and a 14-node North American network (NSF-Net).The results show that at low traffic density, the smaller the value of α, the lower the blocking rate. As the density of services increases, the value of α also to increase, the lower the blocking rate can be guaranteed. Finally, compared with the existing better methods, the algorithm proposed in this paper has a lower blocking rate. The simulation results show that the Tradeoff-RnI algorithm has a much lower connection request blocking rate than the First-Last Fit algorithm and the Block-Assignment algorithm.

La programación de series internacionales en la televisión generalista española (1990 - 2010)

Esta investigación presenta un análisis cuantitativo de la programación de series internacionales en las cadenas generalistas españolas entre 1990 y 2010. Describe la nacionalidad, cadena de emisión original, formatos y series con mayor número de episodios emitidos y de mayor audiencia. También se determinan las tendencias de programación según formatos, temáticas y series en las distintas franjas horarias. En estos años, los formatos más emitidos y de mayor audiencia fueron las sitcoms y las series procedimentales de las networks estadounidenses. Las series internacionales tuvieron un papel esencial en el inicio de emisiones de las cadenas privadas (que las emplearon como producto de relleno) y fueron un valor seguro en el prime time. Las series estadounidenses permitieron a las cadenas generalistas diferenciar su oferta en un ecosistema televisivo de elevada competitividad.

Endometrial Cancer Stem Cells: Role, Characterization and Therapeutic Implications.

Endometrial cancer (EC) is the most frequent gynecological cancer. In patients with relapsed and advanced disease, prognosis is still dismal and development of resistance is common. In this context, endometrial Cancer Stem Cells (eCSC), stem-like cells capable to self-renewal and differentiation in mature cancer cells, represent a potential field of expansion for drug development. The aim of this review is to characterize the role of eCSC in EC, their features and how they could be targeted. CSC are involved in progression, invasiveness and metastasis (though epithelial to mesenchimal transition, EMT), as well as chemoresistance in EC. Nevertheless, isolation of eCSC is still controversial. Indeed, CD133, Aldheyde dehydrogenase (ALDH), CD117, CD55 and CD44 are enriched in CSCs but there is no universal marker nowadays. The most frequently activated pathways in eCSC are Wingless-INT (Wnt)/β-catenin, Notch1, and Hedghog, with a high expression of self-renewal transcription factors like Octamer binding transcription factor 4 (OCT), B Lymphoma Mo-MLV Insertion Region 1 Homolog (BMI1), North American Network Operations Group Homebox protein (NANOG), and SRY-Box 2 (SOX2). These pathways have been targeted with selective drugs alone or in combination with chemotherapy and immunotherapy. Unfortunately, although preclinical results are encouraging, few clinical data are available.

Multidecadal Modulation of the ENSO Teleconnection to Precipitation and Tree Growth Over Subtropical North America

AbstractThe teleconnection of the El Niño/Southern Oscillation (ENSO) to instrumental precipitation and temperature during the cool season over North America is strongest and most temporally stable in the TexMex sector of northern Mexico and the borderlands of southwestern United States. The ENSO impact on North American hydroclimate expands and contracts out of this region on multidecadal timescales, possibly associated with the positive and negative phases of the Atlantic Multidecadal Oscillation. A subset of tree‐ring chronologies from the TexMex sector also has the strongest and most stable ENSO signal detected in the North American network, similar to the strong ENSO signal measured in instrumental climate data from the same region. This subset of chronologies is used to reconstruct the multivariate ENSO index (MEI) as a measure of ENSO impact on North American hydroclimate during the instrumental and preinstrumental eras. The reconstruction exhibits improved fidelity in the frequency domain and better registration of spatial changes in ENSO signal over North America when compared to an MEI reconstruction based on all ENSO‐correlated tree‐ring chronologies irrespective of temporal stability of correlation. When correlated with gridded instrumental and tree‐ring reconstructed Palmer drought indices across North America, the stable MEI estimate reproduces the changes in spatial impact of ENSO signal measured with instrumental data, and it reveals similar multidecadal changes in prehistory, potentially linked to the Atlantic Multidecadal Oscillation. The Great Plains drought of the 1850s and 1860s may have been an example of this Pacific‐Atlantic configuration.

Mental illness media and the paradox of ‘productivity’ in Elementary and Limitless

Abstract This article examines representations of mental illness in North American network television. It is particularly drawn to the CBS police procedurals Elementary (2012–present) and Limitless (2015) as distinct but overlapping stories of mental illness, addiction and intellectual labour. Though depression, drug addiction and anxiety disorders are treated differently in each series, Elementary and Limitless offer complementary narratives of occupational therapy that equate work with mental well-being. While they seem to present a positive image of mentally ill characters with meaningful jobs, Elementary and Limitless measure mental fitness by one’s capacity to work in the same industries often linked to mental illnesses in the first place, resulting in a paradox of productivity. Here the television programmes, much like occupational therapy, tend to overlook critical questions about the socio-economic underpinnings of psychological disorders and encourage viewers to understand the links between mental illness and work in rather myopic ways.

Evaluation of the impact on track of different locomotive running gear architectures

The paper compares two different locomotive architectures in order to evaluate their performances in terms of impact on the track. The reference locomotive is the three-axle bogie locomotive GT46ACe, used in the Australian and North American network, while the second one is a new concept locomotive with BoBoBo wheel arrangement and derived by an existing Italian locomotive, namely E.646. In order to make the comparison possible, the existing Italian locomotive has an increased axle-load and adapted suspensions in order to make its traction performances comparable with the ones of the reference locomotive. The two vehicles have been tested on different tracks and considering different traction levels. The preliminary results show that the BoBoBo wheel arrangement could introduce several benefits with respect to the CoCo one in terms of track load reduction, wear and rolling contact fatigue.

Effects of Policy on Competition in Telecom Equipment Markets: Insights from a Multi-Level Multi-Method Study

Telecom network equipment markets continue to play a significant role in shaping the global information and communications system. At one level, network equipment influences network performance attributes and has direct bearings on the dynamics of innovation at higher layers of the Internet ecosystem. More strategically, participating in network equipment markets is of vital importance for nations in the present era when the openness of the Internet is challenged by actions of many stakeholders. During the past decade, momentum in global equipment markets has shifted from established players such as Ericsson, Nokia Siemens, Alcatel-Lucent and Cisco to emerging firms such as Huawei. Consolidation and takeovers have strongly affected the number of North American network equipment suppliers and raised the question of whether and how public policy could contribute to preventing further decline.Determining how policy choices affect firm-level competitive advantage in the oligopolistic telecom equipment markets is a complex task. Three major challenges need to be overcome that no single method of analysis can handle well. First, the telecom equipment sector is inherently dynamic with ever-changing technology and market dynamics. Second, data documenting the industry and its main players are heterogeneous, of non-uniform quality, and need to be dealt with at different levels of aggregation (firms, nations) simultaneously. Third, due to endogenous and independent decisions at multiple levels (firms, nations), the determination of future scenarios is enormously difficult. Thus, there is a lack of understanding and of strong inference about whether and how public policies, – including measures affecting research and development (RD 2G, 3G, LTE; and optical networks. Data for these analyses were collected from several sources, including Infonetics, Ovum, and public sector databases. We used several econometric techniques including machine-learning approaches to overcome the challenges of heterogeneous data. We then took the findings of these models to build dynamic simulation models of competition that allow us to relax the constraints of the empirical analysis based on historical data, and study the effects of various policy decisions on outcomes such as market shares and revenues. Our analysis illuminates four sets of lessons: First, we demonstrate the limitations of the available data and its implications for what we can and cannot learn about telecom market even after comprehensive modeling efforts. Second, we discuss how competition has changed in the telecom equipment markets over time and how, despite it being an oligopolistic and overall a fairly stable market, certain firms have exploited competitive advantage by sustained commitment to RD Europe, Middle East, and Africa; Central and Latin America, and Asia Pacific.

Editor's Note

Editor's Note

Thinking Differently About Aging: Changing Attitudes Through the Humanities.

Ageism has many cumulative negative health effects, so reducing ageism in college-age youths can have a significant, long-term impact on public health. Reduced ageism decreases the prevalence and severity of many negative health events, such as myocardial infarctions, and can add an average of 7.5 years to the life span. One of the few proven methods for reducing ageist ideation is through participation in a video screening and a pair of follow-up conversations. This intervention is similar to the regular activities of many faculty members in the humanities. Gerontologists' expertise with quantitative studies, qualitative studies, and data analysis is needed to determine what factors can improve the efficacy of the intervention and to demonstrate the long-term health impact of specific interventions. Humanities research also will benefit from expanded understandings of aging and old age. Organizations such as the Gerontological Society of America, the European Network in Aging Studies, and the North American Network in Aging Studies can facilitate interdisciplinary collaboration.

In‐situ CO2 monitoring network evaluation and design: A criterion based on atmospheric CO2 variability

Estimates of surface fluxes of carbon dioxide (CO2) can be derived from atmospheric CO2 concentration measurements through the solution of an inverse problem, but the sparseness of the existing CO2 monitoring network is often cited as a main limiting factor in constraining fluxes. Existing methods for assessing or designing monitoring networks either primarily rely on expert knowledge, or are sensitive to the large number of modeling choices and assumptions inherent to the solution of inverse problems. This study proposes a monitoring network evaluation and design approach based on the quantification of the spatial variability in modeled atmospheric CO2. The approach is used to evaluate the 2004–2008 North American network expansion and to create two hypothetical further expansions. The less stringent expansion guarantees a monitoring tower within one correlation length (CL) of each location (1 CL), requiring an additional eight towers relative to 2008. The more stringent network includes a tower within one half of a CL (½ CL) and requires 35 towers beyond the 1 CL network. The two proposed networks are evaluated against the network in 2008, which temporarily had the most continuous monitoring sites in North America thanks to the Mid‐Continent Intensive project. Evaluation using a synthetic data inversion shows a marked improvement in the ability to constrain both continental‐ and biome‐scale fluxes, especially in areas that are currently under‐sampled. The proposed approach is flexible, computationally inexpensive, and provides a quantitative design tool that can be used in concert with existing tools to inform atmospheric monitoring needs.

Applied Materials Uses Operations Research to Design Its Service and Parts Network

Applied Materials Inc. is the global leader in nanomanufacturing technology solutions. It has a broad portfolio of innovative equipment, service, and software products and supports its customers worldwide with an extensive service and parts network with more than 100 locations. At the end of 2006, Applied Materials decided to evaluate and rationalize the design of its North American network. It set up a detailed optimization model (including 50,000 parts) to develop a network and distribution strategy. To our knowledge, this is the first large-scale multiechelon network-design model that incorporates safety stock inventory costs while considering the effects of lead time and risk pooling. The company used the model's recommendations to reduce costs while maintaining or improving its service to customers. The recommendations included simplifying the distribution network by consolidating depot locations for specific customers and skipping an echelon for others, thus leading to a projected inventory reduction of $10 million. The company is currently implementing these recommendations and has already eliminated five depots. Applied Materials estimates that during the first year of implementation, inventory reductions of $5.24 million and total savings of $1.1 million can be attributed to these network changes.

A Satellite Approach to Estimate Land–Atmosphere $\hbox{CO}_{2}$ Exchange for Boreal and Arctic Biomes Using MODIS and AMSR-E

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Northern ecosystems are a major sink for atmospheric <formula formulatype="inline"><tex Notation="TeX">$\hbox{CO}_{2}$</tex> </formula> and contain much of the world's soil organic carbon (SOC) that is potentially reactive to near-term climate change. We introduce a simple terrestrial carbon flux (TCF) model driven by satellite remote sensing inputs from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Advanced Microwave Scanning Radiometer for EOS (AMSR-E) to estimate surface (<formula formulatype="inline"><tex Notation="TeX">$≪ 10$</tex></formula>-cm depth) SOC stocks, daily respiration, and net ecosystem carbon exchange (NEE). Soil temperature and moisture information from AMSR-E provide environmental constraints to soil heterotrophic respiration <formula formulatype="inline"><tex Notation="TeX">$(R_{h})$ </tex></formula>, while gross primary production (GPP) information from MODIS provides estimates of the total photosynthesis and autotrophic respiration. The model results were evaluated across a North American network of boreal forest, grassland, and tundra monitoring sites using alternative carbon measures derived from tower <formula formulatype="inline"><tex Notation="TeX">$\hbox{CO}_{2}$</tex></formula> flux measurements and BIOME-BGC model simulations. Root-mean-square-error (rmse) differences between TCF model estimates and tower observations were 1.2, 0.7, and 1.2 <formula formulatype="inline"><tex Notation="TeX">$\hbox{g} \cdot \hbox{C} \cdot \hbox{m}^{-2} \cdot \hbox{day}^{-1}$ </tex></formula> for GPP, ecosystem respiration <formula formulatype="inline"><tex Notation="TeX">$({\rm R}_{\rm tot})$</tex> </formula> and NEE, while mean residual differences were 43% of the rmse. Similar accuracies were observed for both TCF and BIOME-BGC model simulations relative to tower results. TCF-model-derived SOC was in general agreement with soil inventory data and indicates that the dominant SOC source for <formula formulatype="inline"><tex Notation="TeX">$R_{h}$</tex> </formula> has a mean residence time of less than five years, while <formula formulatype="inline"><tex Notation="TeX">$R_{h}$</tex> </formula> is approximately 43% and 55% of <formula formulatype="inline"><tex Notation="TeX">$R_{\rm tot}$</tex></formula> for respective summer and annual fluxes. An error sensitivity analysis determined that meaningful flux estimates could be derived under prevailing climatic conditions at the study locations, given documented error levels in the remote sensing inputs. </para>

Accounts of violence from Arabs and Israelis on Nightline

The North American network, ABC-Television, broadcast the news-panel program, Nightline, from Jerusalem during the beginning days of the Second Intifada. One of the main themes of this discussion was the violence, pain and trauma – the civilians killed or wounded, the military's actions, and how it all started. Even the horrible facts of violence must be told or narrated and discussed for their morality, causes, consequences, responsibility and political ramifications. In this sense, violence is discursive. How violence gets told, how versions get constructed or contested, is our focus. Participants used the communicative practices of invoking membership categories and activity terms and formulating events in support of their evaluative viewpoint. These membership categories were often presented by the use of conflicting positionings in referencing persons or events. The ‘conflict’ between descriptive terms draws attention to something problematic. Talk of violence also makes relevant reports of affect/feeling. In reporting violence, affect/feeling is reconstructed by participants as both a consequence and a cause of action, to intensify a condition, to raise moral issues, as an obstacle to be overcome, as a shorthand condition to ascribe of another to invite a telling of the events, or to ascribe as an opponent's political strategy. Such discursive uses of affect/feeling help to make concrete the human costs of violence. In addition, the panelists' answers were designed not only for the interviewer or fellow panelists, but to multiple audiences, including millions of TV viewers in the USA.

An invitation to participate in a North American sediment‐monitoring network

An informal collaboration has been established to encourage the development of a North American network for the collection, analysis, and interpretation of fluvial‐sediment data. The principal objective of the network is to define continental‐scale gradients of mean yield, variability of loads, particle‐size distributions, and natural regimes for suspended and bed sediment released during unstressed to minimally stressed conditions of land use. Extending that goal, a second objective is to identify stream reaches where fluxes of sediment and associated contaminants now are elevated to levels at which water quality and ecological integrity are compromised.

Postmarketing surveillance for human teratogenicity: a model approach.

Most congenital defects associated with prenatal exposures are notable for a pattern of major and minor malformations, rather than for a single major malformation. Thus, traditional epidemiological methods are not universally effective in identifying new teratogens. The purpose of this report is to outline a complementary approach that can be used in addition to other more established methods to provide the most comprehensive evaluation of prenatal exposures with respect to teratogenicity. We describe a multicenter prospective cohort study design involving dysmorphological assessment of liveborn infants. This design uses the Organization of Teratology Information Services, a North American network of information providers who also collaborate for research purposes. Procedures for subject selection, methods for data collection, standard criteria for outcome classification, and the approach to analysis are detailed. The focused cohort study design allows for evaluation of a spectrum of adverse pregnancy outcomes ranging from spontaneous abortion to functional deficit. While sample sizes are typically inadequate to identify increased risks for single major malformations, the use of dysmorphological examinations to classify structural anomalies provides the unique advantage of screening for a pattern of malformation among exposed infants. As the known human teratogens are generally associated with patterns of structural defects, it is only when studies of this type are used in combination with more traditional methods that we can achieve an acceptable level of confidence regarding the risk or safety of specific exposures during pregnancy.

The relative utility of current observation systems to global-scale NWP forecasts

We study 20 cases in which 60-hour Numerical Weather Prediction (NWP) of specific synoptic events have been markedly improved by observations made during the final 15 hours prior to the forecast initial time. For each case, the observing systems which played major rǒles in improving the accuracy of the forecast mean-sea-level pressure (m.s.1.p.) field are identified using a series of Observation System Experiments. The relative utility of each observation type is then assessed according to the frequency, over all cases, with which it delivers a major beneficial impact. The method of multiple case-study employed has the advantage that observation value is assessed according to the benefit delivered to forecasts of events (e.g. cyclogenesis) which are of prime importance to operational meteorology. The method, therefore, provides a useful complement to the conventional Statistical approach which typically yields an ‘average’ benefit, calculated for all regimes (both active and ‘quiet’) occurring over a given period within a specific geographical region. The cases arc selected from the most significant data-impact events detected in routine operational forecasts of m.s.1.p., for Europe and North America, during the period September 1993 to December 1995. Results indicate that, for weather systems developing over North America, radiosonde and aircraft reports contribute major forecast benefits most often, confirming their key rǒle in the North American network. These two observing systems contribute with similar frequency, suggesting that the effectiveness of the less abundant radiosonde reports is boosted significantly by their profile formal. Surface data and cloud-track winds are the next most frequent contributors. For weather systems developing over the North Pacific and North Atlantic, aircraft winds contribute forecast benefits most frequently, and by a wide margin. Conventional surface data also play a key rǒle. Comparison of the utility of wind and temperature data suggests that, on average, the benefit of wind profiles is somewhat greater than that of temperature profiles, and that, in levels above ∼400 hPa, wind data are considerably more valuable than temperature data. The results give insights which can be used to guide the rationalization of existing networks within the northern hemisphere mid latitudes, and the following recommendations are made with a view to improving NWP over the European area. •Acquire more aircraft data over North Atlantic routes and over Europe (including reports during climb and descent). However, caution must be exercised if aircraft data are used to replace profile information from radiosondes. •Deploy more surface observations (e.g. drifting buoys) and shipborne radiosonde ascents over the North Atlantic. •Make more use of pattern-tracking techniques for deriving ‘clear-air’ wind data from satellite water-vapour imagery. •Continue investigation of the effectiveness of observations ‘targeted’ on objectively defined regions where model errors are predicted to grow most rapidly.