640 research outputs found
Erosion Control in Chaco Canyon, New Mexico for the Preservation of Archaeological Sites
No accurate maps have been made of the whole region covered by this report. A very excellent aerial survey has been made of the Navajo Reservation, but this does not extend more than eight miles east of Wijiji, and does not show quite all of the Chaco canyon. No profile or cross-section of Chaco Canyon exists, except for the maps made by the National Parks Service. As these cover only about three-quarters of a mile, they are not of great assistance in matters concerned with the grade of the stream bed. They are a valuable start, however, and they have been drawn on freely for any information which they contain
Letter from W[illia]m M. Chauvenet to John Muir, 1909 Dec 28.
REGIS CHAUTENET. W. M. CHAUVENET.REGIS CHAUVENET & BROTHER.MINING ENGINEERSANALYTICAL CHEMISTS AND ASSAYERS.937 EQUITABLE BUILDING,DENVER.LABORATORIES:620 CHESTNUT STREET.St. Louis, Dec. 28-1909,John Muir,President of Society for the preservation of National Parks. 302 Mills Building, San Francisco. Dear Professor Muir,The information conveyed in your Statement of the Hetch-Hetchy case to date shocks me so deeply that I feel equal, could I get the chance, to eloquence enough and rage enough to stay any congress or to sway any convention.Your work, on mountain and on glacier I have delighted in from my college days, and my work in the mining school. With you and your dog Stickeen, I, too, have followed to the fountains of the Fairweather mountains- such a dog and such a man are worth following to the death- and so in many other adventures when the earth was shaking and the loose stones rolling from their ledges, have I run in with you to [dep ?] gorges, to see them rock and fall. In brief, my dear Sir, you have often made me glad in spirit and more brave in courage by your beautiful descriptions of things I love the best and to any cause,that is your cause, I would bring what help I can.The writing of letters to, officials in Washington has proved quite useless in the past, and yet again have I set some of my friends on the trail of this outrage which is sought by certain unnatural men in the West and whatever influence our Missouri Senators may exercise, I think I can command in some measure.The purpose of the men who would destroy the Hetch-Hetchy valley being the enrichment of themselves I do not think you need fear that the people will stand behind, any legislation which will allow such a crime. I send you Five dollars, only asking that you personally indorse the check and that you will command me in the service of this work when ever I may help here in Missouri. Would that it were more, and that I might in person talk with you about the matter in which I am so deeply interested.With great respect,[Illegible]0466
Modelling the Dynamics of Translocated Populations
Climate change is widely accepted as one of the worst threat to the worldâs biodiversity. A
recently proposed solution to help species survive climate change is âassisted colonisationâ,
i.e. translocations of species to more suitable sites. Although assisted colonisation could be
a powerful conservation tool, translocations are known to have a low success rate despite
being commonly-used. Before promoting assisted colonisation as a solution, we need to
make two major advances: first, understand how translocated species will respond to a
changing climate and if their population viability will be compromised and, second, develop
a quantitative framework to improve the success rates of conservation translocation under
global environmental change. Those were the two aims of my thesis. The hihi (stitchbird;
Notiomystis cincta ) was used as a study species. It has been the subject of several
translocations in the past few decades and every translocated population is intensely
monitored, yielding long-term demographic datasets.
Climate was found to be a key factor in the dynamics of translocated population, and thus
viability. However, it may also interact with other intrinsic factors like density and age to
influence speciesâ long-term persistence. A stochastic population model built to quantify the
potential impacts of future climate change on translocated populationsâ long-term
persistence showed the importance of taking into account the impact of longer and more
frequent extreme weather on translocated populationâs viability. Moreover, MaxEnt was
found to be a good habitat suitability model for translocated populations and used to
identify future translocation sites for the hihi under climate change. Finally, quantitative
guidelines for the planning and implementation of assisted colonisations were developed.
They address the known issues impeding translocation success, and, if used, will maximise
the success of assisted colonisations
Simulation of the RPL Routing Protocol for IPv6 Sensor Networks: two cases studies
International audienceThe routing protocol for low power and lossy networks (RPL) was recently designed in the ROLL working group at IETF. Few simulation tools exist that enable its evaluation in order to prepare for its real deployment. In this paper, we provide a new evaluation of this protocol with two approaches using two different simulators adapted to our needs. We first evaluated the value of mobile sinks in wireless sensor networks to extend the network lifetime using a sensor network simulator, WSNet, augmented by our own RPL module. We then focus on the performance comparison of simulated sensor networks and real powerline communication networks (PLC) using the RPL capable COOJA simulator augmented by our own PLC module. In each case, we justify the simulator choice, describe the tools implemented and present the obtained results. Our studies give two new RPL evaluations and show the interest of choosing a simulation tool adapted to the targeted study with the associated software developments. As a conclusion, we demonstrated how these two case studies can be combined in a heterogeneous network architecture to extend its global lifetime
Targeted management buffers negative impacts of climate change on the hihi, a threatened New Zealand passerine
In order to buffer the risks climate change poses to biodiversity, managers need to develop new strategies to cope with an increasingly dynamic environment. Supplementary Feeding (SF) is a commonly-used form of conservation management that may help buffer the impacts of climate change. However, the role of SF as an adaptation tool is yet to be fully understood. Here we used the program MARK to quantify the relationship between weather (average temperature and total precipitation) and vital rates (survival and recruitment) of an island bird population, the hihi Notiomystis cincta, for which long term demographic data are available under periods of little and ad libitum SF. We then used predictive population modelling to project this populationâs dynamics under each management strategy and several climate change scenarios in accordance with the Intergovernmental Panel on Climate Change predictions. Our stochastic population projections revealed that ad libitum SF likely buffer the population against heavier rainfall and more stochastic precipitation patterns; no buffering effect on temperature was detected. While the current SF approach is unlikely to prevent local extinction of the population under increasing temperatures, SF still presents itself as a valuable climate change adaptation tool by delaying extinction. To the best of our knowledge, this is the first study to quantify the interaction between climate and SF intensity of a threatened population. We call for on-going critical evaluation of management measures, and suggest that novel adaptation solutions that combine current approaches are required for conserving species with limited opportunity for dispersal
The Role of Retailers in the Selection of Healthful, Low-Cost Products among WIC Recipients
Background: Currently, there is a gap in the literature examining attitudes, challenges, and opportunities around the promotion of healthy and low-cost options to WIC recipients from a retailer perspective. Methods: Five interviews were conducted with retailers to explore these construct as part of the formative research phase of the Duke-UNC USDA Center For Behavioral Economics And Healthy Food Choice Research (BECR). Interviewees were senior employees in national or regional grocery store chains with experience in WIC sales and administration. Results: Most interviewees were enthusiastic about the potential of promotions of healthy, low-cost food items to WIC recipients. The potential for increased revenue is a motivator for retailers to increase marketing efforts to WIC customers. The transition to EBT is also relevant to the promotion of healthy and low-cost food items because it frees up the costs and time of the store associated with administering WIC benefits. The possibility of increased revenue from fresh fruit and vegetable sales presents an area of potential collaboration between public health officials and retailers. The main barriers to increased promotion were the risk of stigmatization and restrictions around promotion of store items directly to WIC customers. Conclusions: This research indicates a need for public health practitioners to work with retailers to identify mechanisms to promote healthier options to WIC customers without creating additional stigma.Master of Science in Public Healt
Protocoles de support IPv6 pour réseaux de capteurs sur courant porteur en ligne
This thesis demonstrate the relevance of Powerline Communication (PLC) usage for sensor networks applications. We focus in particular on the low power and low data rate PLC technol- ogy "Watt Pulse Communication" (WPC) developed by the Watteco company and justify its usage for sensor network applications. We situate the WPC technology in the PLC landscape and define compatible protocols. We then describe the WPC module and the PLC media im- plementation in the COOJA network simulator. This allows us to propose a network solution over this technology, leveraging on the adaptation of the 802.15.4 standard over the WPC tech- nology. We then demonstrate the benefit of media convergence at the network layer level, with the use of the IPv6 standard that we adapted over our PLC solution thanks to the 6LoWPAN protocol. We justify the usage of standards protocols over our PLC solution and show that a routing solutions must be developed over WPC. We show through experiments that our PLC solution match low power and lossy network (LLNs) criterions for which the RPL standard pro- tocol has been designed. We justify the usage of this routing protocol over our PLC solution, and validate its implementation through 2 experiments conducted in tertiary types buildings. Respectively composed of 7 and 26 PLC nodes, results show that the routing topology created by RPL enable the coverage an entire floor of a tertiary building with a tree based topology and 3 hops maximum path length. We also show that the WPC technology exhibits a high connectivity between nodes and that the link quality is highly dynamic. Though, we observed that the routing topology was able to handle these variations. We point out the limitations of our PLC solution, which presents high delays and low throughput, creating high constraints on applications. Our sensor network solution over PLC relies on the IP standard, enabling packets exchanges with other technologies using the same protocol. In particular, we study the possi- bility to create heterogeneous networks mixing the WPC technology with 802.15.4 radio. We show that our protocol stack used over PLC enable to create this type of network, in order to benefit from the best of these 2 worlds. We purpose an architecture of a hybrid Radio / PLC node enabling to transfer packets between these 2 media. Then, we show that the combined usage of these 2 media increase the number of available paths and facilitate the routing, while diminishing the number of hops and possible unreachability of nodes. We then demonstrate that the addition of PLC and Radio/PLC nodes in a RF based battery powered sensor network enable to relieve their routing charge in order to expand their lifetime. We then continue the energy study with a power consumption optimization of a wireless sensor network platform from the hardware and software standpoint. We first determine the operating frequency, the wake up frequency and the mode of operation of the micro controller offering the lowest power consump- tion. We then conduct an energy study of 4 different radio transceivers using the 2.4 GHz and 868 MHz frequency band, in order to determine the most efficient architecture. We determine the protocols parameters and the software optimization to reach the lower power consumption of this architecture. Finally, we realize the energy study of several probes than can be embedded on the node, according to their nature and functioning mode. Our final architecture exhibits a total power consumption that is lower than 17 ÎŒW, with an applicative reporting each 10 minutes and the maintenance of the reachability with the network. We also mention in annex parts our implication in standards developments organizations such as the IETF a the IPSO alliance, that allow us to validate the implementation of our solution through interoperability events.Cette theÌse deÌmontre la pertinence de lâutilisation du Courant Porteur en Ligne (CPL) pour des applications de reÌseaux de capteurs. Nous nous focalisons sur la technologie basse consomma- tion et bas deÌbit "WPC" deÌveloppeÌe par la socieÌteÌ Watteco et nous montrons que son utilisation est justifieÌe pour des applications de reÌseaux de capteurs. Nous situons la solution WPC dans le paysage du CPL et deÌterminons les protocoles compatibles. Nous deÌcrivons ensuite lâimpleÌ- mentation du module WPC et du meÌdia CPL dans le simulateur de reÌseau COOJA afin de proposer une solution reÌseau reposant sur lâadaptation du standard 802.15.4 sur la technologie WPC. Nous deÌmontrons ensuite lâinteÌreÌt de la convergence des meÌdias au niveau reÌseau par lâutilisation du standard IPv6, que nous adaptons sur notre solution CPL graÌce au protocole 6LoWPAN. Nous justifions lâutilisation des protocoles standards de lâIETF sur notre solution CPL et nous montrons quâune solution de routage sur CPL doit eÌtre deÌveloppeÌe. Nous montrons par des expeÌrimentations que notre solution CPL correspond aux criteÌres des reÌseaux basse puis- sance et supportant les pertes de transmissions (LLNs) pour lesquels le protocole standard RPL a eÌteÌ conçu. Nous justifions lâutilisation de ce protocole sur CPL, et validons son impleÌmenta- tion dans le cadre de 2 expeÌrimentations. FormeÌes respectivement de 7 puis 26 noeuds CPL, les reÌsultats montrent que le routage creÌeÌ par RPL permet de couvrir un eÌtage dâun baÌtiment avec une topologie de type arbre et une profondeur de 3 sauts maximum. Nous montrons eÌgalement que la technologie WPC permet une connectiviteÌ importante entre les noeuds du reÌseau et que la qualiteÌ des liens est fortement dynamique, mais que le routage permet de sâadapter aÌ ces variations. Nous pointons eÌgalement les limites de notre solution CPL qui preÌsente des deÌlais importants et des deÌbits faibles, geÌneÌrant de contraintes fortes sur les applications. Notre solu- tion de reÌseau de capteur sur CPL repose sur le standard IP, permettant des eÌchanges de paquets avec dâautres technologies. Nous eÌtudions ainsi la possibiliteÌ de creÌer des reÌseaux heÌteÌrogeÌnes meÌlangeant la technologie WPC et radio 802.15.4. Nous montrons que notre pile protocolaire permet la creÌation de ce type de reÌseau, afin de profiter du meilleur des 2 mondes. Nous deÌcri- vons ainsi lâarchitecture dâun noeud hybride Radio FreÌquence (RF) / CPL permettant de faire transiter les paquets entre ces 2 meÌdias. Nous montrons ensuite que lâutilisation combineÌe de ces 2 meÌdias augmente le nombre de chemins disponibles et permet de faciliter le routage, en diminuant le nombre de sauts et le risque que certains noeuds du reÌseau soient inaccessibles. Nous deÌmontrons ensuite que lâinjection de noeuds CPL et RF/CPL dans un reÌseau formeÌ de noeuds RF sur batterie permet de les deÌlester de leur charge de routage afin de prolonger leur dureÌe de vie. Nous preÌsentons ensuite une optimisation eÌnergeÌtique mateÌrielle et logicielle dâun noeud radio. Nous deÌterminons les parameÌtres des protocoles et les optimisations logicielles per- mettant de tirer au mieux partie de cette architecture et nous reÌalisons lâeÌtude eÌnergeÌtique de la sonde embarqueÌe sur le noeud. Au final, notre architecture preÌsente une consommation totale infeÌrieure aÌ 17 ÎŒW. Nous indiquons dans les annexes nos implications dans les organismes de standardisation qui ont permis de valider lâimpleÌmentation
Utilization and Benefits of the Farm to School Program in the United States
Approximately 60% and 90% of children in the United States age 2-18 do not meet recommendations for fruit and vegetable consumption, respectively. School meals influence dietary quality, as these programs provide up to 75% of childrenâs daily caloric intake. These programs are particularly important for children eligible for free or reduced price (FRP) meals, as they rely more on school meals compared to children from higher income households. F2S is an optional program for school districts that facilitates getting local food procurement and has been shown to improve school meal quality. This dissertation uses the 2015 F2S Census, a survey sent to all school districts in the United States in 2015 about their level of engagement with F2S. In the first aim, we explored demographic predictors of any F2S participation, and number of activities among participating districts. Compared to urban school districts, suburban and rural school districts were less likely to participate in F2S (aOR 0.53, 95% CI 0.39-0.72; aOR 0.42, CI 0.30-0.57, respectively). A greater percent of FRP eligibility was associated with reduced odds of F2S participation (Z-score OR 0.74, 95% CI 0.64-0.85). State legislation significantly moderated the relationship between free and reduced price (FRP) eligibility and F2S participation. Few district demographic characteristics were significant when exploring level of F2S among participating districts. In the second aim, we examined the association between frequency of serving local fruits and vegetables (FV) in the cafeteria and self-reported benefits (e.g. reduced food waste) of F2S among participating districts. At least one benefit of F2S participation was reported by 75% of participating F2S districts. Compared to those that did not serve local FV, districts serving local fruit have 1.77 times the odds (95% CI 1.20, 2.60) and local vegetables 3.05 times the odds (95% CI 2.05, 4.53) of reporting a benefit of F2S participation. Each benefit was analyzed individually but generally followed this trend of increased local FV service associated with greater odds of reporting benefits. The results of this dissertation can inform outreach and technical assistance efforts, which are critical to expanding F2S and promoting equity in access to F2S programs.Doctor of Public Healt
Poster Abstract: Interconnecting Low-Power Wireless and Power-Line Communications using IPv6
Wireless sensor networks for building automation and energy management has made great progress in recent years, but the inherent indoor radio range limitations can make communication unpredictable and system deployments difficult. Low-power radio can be combined with low-power Power-Line Communication (PLC) to extend the range and predictability of indoor communication for building management and automation systems. We take the first steps towards exploring the system implications for integration of low-power wireless and PLC in the same network. We leverage IPv6, which allow networks to exist over multiple physical communication media as well as the RPL routing protocol for low-power lossy networks
Heterogeneous PLC-RF networking for LLNs
Session Posters & DemosInternational audienceDans le contexte de l' Ă©volution de l'automatisation des maisons, des bĂątiments et des villes, notre vision des futures infrastructures de communication place le rĂ©seau CPL comme le point central. GrĂące Ă la convergence des couches rĂ©seau autour d'IPv6, nous montrons que l'intĂ©gration du CPL avec les rĂ©seaux de capteurs sans fil est possible mĂȘme dans des dispositifs trĂšs contraints pour offrir une augmentation significative de leur durĂ©e de vie, de leur fiabilitĂ© et de leurs capacitĂ©s de routage
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