Earth Hummocks in the Sunshine Area of the Rocky Mountains, Alberta and British Columbia

Earth hummocks were found on the Continental Divide of the Rocky Mountains in a non-permafrost environment. Many hummocks show involutions of organic layers within 25 cm of the surface, suggesting that the hummocks are still active. The soil material is a non-plastic, silt-textured volcanic ash. During brief periods in the spring the upper soil horizons can become super-saturated with water; the soil then becomes liquid, resulting in involutions in the surface layers. This mechanism is generally erosional and it is unlikely that it contributed to the formation of earth hummocks. The hummocks are believed to be relict features that were formed under colder conditions, when permafrost was likely present in the ground.Key words: Rocky Mountains, hummocks, permafrost, soil horizonsMots clés: Rocheuses, monticules, pergélisol, horizons du so

Properties of Channel Interference for Wi-Fi Location Fingerprinting

Localization systems for indoor areas have recently been suggested that make use of existing wireless local area network (WLAN) infrastructure and location fingerprinting approach. However, most existing research work ignores channel interference between wireless infrastructures and this could affect accurate and precise positioning. A better understanding of the properties of channel interference could assist in improving the positioning accuracy while saving significant amounts of resources in the location-aware infrastructure. This paper investigates to what extent the positioning accuracy is affected by channel interference between access points. Two sets of experiments compare how the positioning accuracy is affected in three different channel assignment schemes: ad-hoc, sequential, and orthogonal data is analyzed to understand what features of channel interference affect positioning accuracy. The results show that choosing an appropriate channel assignment scheme could make localization 10% more accurate and reduces the number of access points that are required by 15%. The experimental analysis also indicates that the channel interference usually obeys a right-skewed distribution and positioning accuracy is heavily dependent on channel interference between access points (APs)

Probing Broad Absorption Line Quasar Outflows: X-ray Insights

Energetic outflows appear to occur in conjunction with active mass accretion onto supermassive black holes. These outflows are most readily observed in the approximately 10% of quasars with broad absorption lines, where the observer's line of sight passes through the wind. Until fairly recently, the paucity of X-ray data from these objects was notable, but now sensitive hard-band missions such as Chandra and XMM-Newton are routinely detecting broad absorption line quasars. The X-ray regime offers qualitatively new information for the understanding of these objects, and these new results must be taken into account in theoretical modeling of quasar winds.Comment: Submitted to Advances in Space Research for New X-ray Results from Clusters of Galaxies and Black Holes (Oct 2002; Houston, TX), eds. C. Done, E.M. Puchnarewicz, M.J. Ward. Requires cospar.sty (6 pgs, 5 figs

Using a Cell-based WLAN Infrastructure Design for Resource-effective and Accurate Positioning

A large scale WLAN infrastructure requires the placement of many thousands of access points (APs). The current approach is to deploy these in an empirical and ad-hoc manner. However, this deployment results in poor resource utilization and inaccurate positioning due to signal overlap and black spots. In this paper, we propose three structured approaches to WLAN infrastructure deployment that would allow better positioning accuracy and optimal coverage. These three approaches make use of triangular, square, and hexagonal configurations. Our results show that all three are more effective in both 2-D and 3-D space than any of the current ad-hoc or empirical approaches to AP deployment. Overall, the hexagonal approach is the most cost effective and accurate. It allows better positioning with fewer APs than are normally used. As a further contribution, 3-D rendering of buildings and wireless signal coverage could give engineers a concrete visualization that helps them to foresee where the blind spots are in advance and how signal varied across multi-story buildings, such that engineers could estimate the optimal number of APs and where they should be placed

Changes in resource partitioning between and within organs support growth adjustment to neighbor proximity in <i>Brassicaceae</i> seedlings.

In shade-intolerant plants, the perception of proximate neighbors rapidly induces architectural changes resulting in elongated stems and reduced leaf size. Sensing and signaling steps triggering this modified growth program have been identified. However, the underlying changes in resource allocation that fuel stem growth remain poorly understood. Through &lt;sup&gt;14&lt;/sup&gt; CO &lt;sub&gt;2&lt;/sub&gt; pulse labeling of &lt;i&gt;Brassica rapa&lt;/i&gt; seedlings, we show that perception of the neighbor detection signal, low ratio of red to far-red light (R:FR), leads to increased carbon allocation from the major site of photosynthesis (cotyledons) to the elongating hypocotyl. While carbon fixation and metabolite levels remain similar in low R:FR, partitioning to all downstream carbon pools within the hypocotyl is increased. Genetic analyses using &lt;i&gt;Arabidopsis thaliana&lt;/i&gt; mutants indicate that low-R:FR-induced hypocotyl elongation requires sucrose transport from the cotyledons and is regulated by a PIF7-dependent metabolic response. Moreover, our data suggest that starch metabolism in the hypocotyl has a growth-regulatory function. The results reveal a key mechanism by which metabolic adjustments can support rapid growth adaptation to a changing environment

Pilot study on university students' opinion about STEM studies at higher education

The percentages of women enrolled in higher education in the STEM sector are significantly lower than those of men. Overall, gender representation in science, technology, engineering and mathematics degrees in Europe is not balanced. The Leaky Pipeline phenomenon, marked by gender stereotypes, makes the latent gender gap a relevant topic of study. Studies exist on academic performance, self-perception, self-efficacy, outcome expectations; however, studying gender stereotypes linked to STEM studies is also essential. It is necessary to know the social and family context in which young people have grown up, as well as their perception of such studies. To study gender stereotypes of university students about STEM studies, a questionnaire has been designed for empirical validation. For the design of the instrument, to be validated, items from other instruments have been taken and adapted to Spanish. After the design of the instrument, an online pilot study has been applied in the University of Salamanca, the University of Valencia and the Polytechnic University of Valencia. A total of 115 people answered the questionnaire. The results of the pilot study reveal that the study sample is not particularly marked by gender stereotypes about gender equality in STEM. Also, the sample is receptive to learning about science and applying it in their lives. On the other hand, the idea that women have to give up their studies and careers to look after their families and children is rejected. The idea that men are more interested in university studies than women is also rejected. At the same time, the sample is aware of the difficulties that women encounter in the STEM sector. Another optimistic point of the results is that there are no alarming data on bad experiences due to gender. In the future, the study will be replicated on a larger scale

Calotropis procera: um levantamento preliminar sobre as suas capacidades de fitoextração no Brasil

Calotropis procera (Apocynaceae) is a non-native species that has its origin in Africa and Asia, but was introduced into the northeastern region of Brazil in the beginning of last century. In some areas, the dry biomass of C. procera is used as animal feed. However, previous studies indicated that the species is capable of accumulating many chemical elements. On the other hand, it could also mean that this species may be used for phytoremediation. Hence, we used neutron activation analysis, k0-method, to test the capability of the leaves of C. procera to accumulate trace elements. The study was carried out in two distinct areas (polluted and non-polluted) in the State of Pernambuco, Brazil. Our results indicate that new elements can be added to the list of elements taken up by C. procera, thus contributing to the understanding of the biology of this plant species as an accumulator of trace elements. Some elements, such as Ba and Sr, have higher concentrations in the non-polluted areas than in polluted areas. Thus, the presence of many trace elements in C. procera indicates that its use as animal feed should be viewed with extreme caution. However low levels of these trace elements in C. procera do not indicate that this species is a hyper-accumulator plant.Key words: phytoremediation, biological invasion, invasive species, Pernambuco.Calotropis procera (Apocynaceae) é uma espécie exótica originária da África e Ásia tropical, introduzida na região nordeste do Brasil no início do século passado. Em algumas regiões do Brasil e do mundo, a biomassa seca de C. procera é utilizada como alimento forrageiro para animais. Entretanto, muitos estudos indicam que essa espécie é capaz de acumular diversos elementos químicos. Isso pode significar que a espécie também pode ser utilizada em processos de fitorremediação. Dessa forma, foi realizada uma análise de ativação neutrônica, método k0, para testar a capacidade das folhas de C. procera acumularem elementos-traço. O estudo foi realizado em duas áreas distintas (poluídas e não poluídas) no estado de Pernambuco, Brasil. Nossos resultados indicam que novos elementos podem ser adicionados à lista de elementos-traço absorvidos por C. procera, contribuindo para o entendimento da biologia dessa espécie como acumuladora de elementos-traço. Alguns destes, tais como Ba e Sr, ocorreram em maiores concentrações em áreas não-poluídas em comparação com áreas poluídas. Dessa forma, o uso de C. procera como ração animal deve ser vista com extrema cautela. Entretanto, as baixas concentrações desses elementos-traço não sugerem que C. procera seja uma hiperacumuladora.Palavras-chave: fitorremediação, invasão biológica, espécie invasora, Pernambuco

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02