39 research outputs found

    Perceptions of trekking tourism and social and environmental change in Nepal's Himalayas

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    The Himalayas are among the world’s youngest mountain ranges. In addition to the geologic processes of mountain building and erosion, they are also highly vulnerable to human influenced change, occurring at local, national, regional, and international scales. A photo-elicitation methodology is employed to show how residents perceive those changes from historical perspectives, as well as their current conditions and impacts on their daily lives. Nepal’s Khumbu region has undergone major social and environmental transformations since the 1960s when international trekking first began to influence the area's economy. The current perceptions of Khumbu residents of these changes is assessed through photo-elicitation interviews. Their responses are placed in the historical context of: (i) institutional and political changes, much of which have been driven by national government policies; (ii) social and economic changes, for which the tourism economy has been central; and (iii) environmental changes, reflecting the impacts of resource management and climate change. The mostly positive perceptions of Khumbu residents toward how their region has changed reflects general improvements in the physical and cultural landscapes of the Khumbu over time, as well as its continuing geographic isolation, which has helped to slow the rate of globalization, while also keeping the region a dynamic and popular tourist destination

    The SPTPoL extended cluster survey

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    We describe the observations and resultant galaxy cluster catalog from the 2770 deg2 SPTpol Extended Cluster Survey (SPT-ECS). Clusters are identified via the Sunyaev-Zel'dovich (SZ) effect and confirmed with a combination of archival and targeted follow-up data, making particular use of data from the Dark Energy Survey (DES). With incomplete follow-up we have confirmed as clusters 244 of 266 candidates at a detection significance ξ ≥ 5 and an additional 204 systems at 4 4 threshold, and 10% of their measured SZ flux. We associate SZ-selected clusters, from both SPT-ECS and the SPT-SZ survey, with clusters from the DES redMaPPer sample, and we find an offset distribution between the SZ center and central galaxy in general agreement with previous work, though with a larger fraction of clusters with significant offsets. Adopting a fixed Planck-like cosmology, we measure the optical richness-SZ mass (l - M) relation and find it to be 28% shallower than that from a weak-lensing analysis of the DES data-a difference significant at the 4σ level-with the relations intersecting at λ = 60. The SPT-ECS cluster sample will be particularly useful for studying the evolution of massive clusters and, in combination with DES lensing observations and the SPT-SZ cluster sample, will be an important component of future cosmological analyses

    Detection of CMB-cluster lensing using polarization data from SPTpol

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    We report the first detection of gravitational lensing due to galaxy clusters using only the polarization of the cosmic microwave background (CMB). The lensing signal is obtained using a new estimator that extracts the lensing dipole signature from stacked images formed by rotating the cluster-centered Stokes Q U map cutouts along the direction of the locally measured background CMB polarization gradient. Using data from the SPTpol 500     deg 2 survey at the locations of roughly 18 000 clusters with richness λ ≥ 10 from the Dark Energy Survey (DES) Year-3 full galaxy cluster catalog, we detect lensing at 4.8 σ . The mean stacked mass of the selected sample is found to be ( 1.43 ± 0.40 ) × 10 14 M ⊙ which is in good agreement with optical weak lensing based estimates using DES data and CMB-lensing based estimates using SPTpol temperature data. This measurement is a key first step for cluster cosmology with future low-noise CMB surveys, like CMB-S4, for which CMB polarization will be the primary channel for cluster lensing measurements

    Atividade radicular da soja: definição de um método Soybean root activity: methodology definition

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    As técnicas de estudo radicular são trabalhosas e, dentre os métodos mais utilizados no Brasil, destacam-se a trincheira ou parede do perfil, blocos ou monólito, placa com pregos e trado. Essas técnicas utilizam amostragem destrutiva e direta das raízes. Com o objetivo de adaptar um método de avaliação da atividade radicular da cultura da soja utilizando nitrato de rubídio (RbNO3), realizou-se um experimento em Botucatu - SP. O experimento constituiu-se de duas etapas, sendo uma em campo e outra em casa de vegetação. Plantas de soja foram cultivadas em vasos de 15 dm³ de amostras de Nitossolo Vermelho em casa de vegetação. Aos 25 DAE, aplicaram-se 3 mL de solução de RbNO3 nas doses de 0,0; 0,5; 1,0; e 2,0 mg dm-3 de Rb, à 0,05 m de profundidade no centro de cada vaso. A parte aérea das plantas foi coletada e separada em caule + pecíolo e limbo foliar aos dois, quatro e seis dias depois da aplicação de RbNO3. Em campo, aplicaram-se 3 mL de RbNO3 (1,0 mg dm-3 de Rb) em diferentes distâncias da planta (0,075, 0,15 e 0,225 m) e nas profundidades de 0,05; 0,10; 0,20; 0,40; e 0,60 m. A parte aérea das plantas foi coletada quatro dias depois da aplicação de RbNO3. A soja não apresentou fitotoxicidade ao RbNO3, o que foi eficiente na determinação da atividade radicular da cultura.<br>Root study techniques are labor intensive. Among the most frequently used methods are the trench or profile wall, block or monolith, needle board and hand auger. These techniques use destructive and direct root sampling. With the objective of adapting an evaluation methodology of soybean root activity based on Rubidium Nitrate, an experiment was carried out in Botucatu, SP, Brazil, in two phases; one in the field and the other in a greenhouse. Soybean plants were grown in 15 L pots. 25 DAE, 3 mL of Rubidium Nitrate solution was applied at 0; 0.5; 1.0 and 2.0 mg dm-3, at a depth of 0.05 m in the middle of each pot. The plants shoot was collected and divided in stalk + petiole and leaf after 2, 4 and 6 days of RbNO3 application. In the field, portions of 3.0 mL RbNO3 were applied at depths of 0.05; 0.10; 0.20; 0.40 and 0.60 m. The plant shoot was collected 4 days after RbNO3 applications. No phytotoxicity of RbNO3 to soybean plants was observed. RbNO3 was efficient to determine root activity

    High-resolution measurements of the DT neutron spectrum using new CD foils in the Magnetic Recoil neutron Spectrometer (MRS) on the National Ignition Facility

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    The Magnetic Recoil neutron Spectrometer (MRS) on the National Ignition Facility (NIF) measures the DT neutron spectrum from cryogenically layered Inertial Confinement Fusion (ICF) implosions. Yield, areal density, apparent ion temperature and directional fluid flow are inferred from the MRS data. This paper describes recent advances in MRS measurements of the primary peak using new, thinner, reduced-area deuterated plastic (CD) conversion foils. The new foils allow operation of MRS at yields 2 orders of magnitude higher than previously possible, at a resolution down to ~200 keV FWHM
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