218 research outputs found

    COTTONWOOD RIPARIAN SITE SELECTION ON THE CHEYENNE RIVER SIOUX RESERVATION

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    The construction of the Oahe Dam on the Missouri River eliminated thousands of acres ofriparian and floodplain lands on the Cheyenne River Sioux Reservation in South Dakota. Restoration is needed to replace wildlife habitat. This study focused on site selection for native cottonwood (Populus deltoides Bartr. Ex Marsh. ssp. Monilifers (Ait.) Eckenwalde) restoration to help mitigate this loss. Geographic information systems technologies were used to develop a suitability model for cottonwood restoration. Tribal lands were extracted from a digital dataset oflandownership. Those touched by or included in a 46 m border of the Moreau River were candidate sites. Of the 182 candidates, 50 sites were randomly selected for model development. Slope, aspect, stream length and number, soil properties, and land cover criteria were given a numeric score and these were summed; the lowest total score possible was -7 and the highest score possible was 33. The sample sites were evaluated and ranked as high (21 to 33, 7 sites), medium (7 to 20, 35 sites), or low (-7 to 6, 8 sites) for growth and maintenance of riparian cottonwood forests. Five sites were selected for cottonwood restoration using the model developed. Bare root trees were planted mechanically and by hand. Drought conditions limited survival and 50% ofthe area was replanted. Further data collection may increase the use of geographic information system (GIS) technology and facilitate site selection for cottonwood restoration in the northern Great Plains

    COTTONWOOD RIPARIAN SITE SELECTION ON THE CHEYENNE RIVER SIOUX RESERVATION

    Get PDF
    The construction of the Oahe Dam on the Missouri River eliminated thousands of acres ofriparian and floodplain lands on the Cheyenne River Sioux Reservation in South Dakota. Restoration is needed to replace wildlife habitat. This study focused on site selection for native cottonwood (Populus deltoides Bartr. Ex Marsh. ssp. Monilifers (Ait.) Eckenwalde) restoration to help mitigate this loss. Geographic information systems technologies were used to develop a suitability model for cottonwood restoration. Tribal lands were extracted from a digital dataset oflandownership. Those touched by or included in a 46 m border of the Moreau River were candidate sites. Of the 182 candidates, 50 sites were randomly selected for model development. Slope, aspect, stream length and number, soil properties, and land cover criteria were given a numeric score and these were summed; the lowest total score possible was -7 and the highest score possible was 33. The sample sites were evaluated and ranked as high (21 to 33, 7 sites), medium (7 to 20, 35 sites), or low (-7 to 6, 8 sites) for growth and maintenance of riparian cottonwood forests. Five sites were selected for cottonwood restoration using the model developed. Bare root trees were planted mechanically and by hand. Drought conditions limited survival and 50% ofthe area was replanted. Further data collection may increase the use of geographic information system (GIS) technology and facilitate site selection for cottonwood restoration in the northern Great Plains

    Altruism in medical education: assessing attitudes of hospital in-patients towards face-to-face contact with medical students during the COVID-19 pandemic

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    Abstract Background Limited research indicated patients were largely amenable to seeing medical students pre-pandemic. However, the COVID-19 pandemic has highlighted the potential risk of nosocomial transmission and harm to patients from students. Patient opinions regarding these risks remain unexplored, which impacts elicitation of informed consent. We aim to identify these, and explore whether reflection on the risks and benefits of direct student interaction influenced patients’ attitudes. For guidance, we further explored measures to reduce perceived infection risk. Method We designed an original questionnaire for a cross-sectional study, completed by 200 inpatients from 25 wards between 18/02 and 16/03/2022 at Derriford Hospital, Plymouth. Patients in intensive care, with active COVID-19 infection or unable to comprehend the study information were excluded. The responses of a guardian were recorded for inpatients under 16. 17 questions were included - the initial question, reporting willingness to talk with and be examined by students, was repeated following nine questions exploring risks and benefits of student interaction. A further four questions addressed reducing the perceived infection risk. Data is summarised using frequencies and percentages, and with Wilcoxon signed-rank and rank-sum tests of association. Results 85.4% (169/198) of participants gave an initial positive response to seeing medical students, and despite a third of participants changing their response 87.9% (174/197) remained willing after the survey resulting in no significant change. Furthermore, 87.2% (41/47) of those who perceived themselves at severe risk of harm from COVID-19 remained happy to see students. Participants reported reassurance knowing students were: fully vaccinated (76.0%); wearing masks (71.5%); lateral flow test negative within the last week (68.0%) and wearing gloves and gown (63.5%). Conclusion This study demonstrated the willingness of patients to engage in medical education despite recognised risks. Patient reflection on the risks and benefits of student interaction did not significantly reduce numbers willing to see students. Even those perceiving a risk of serious harm remained happy to have direct student contact – a demonstration of altruism in medical education. This suggests informed consent should include discussion of infection control measures, risks and benefits to patients and students, and offer alternatives to direct inpatient contact. </jats:sec

    Synthesis and characterization of metal (M=Al or Ga) 2-phosphino (phenolate/benzenethiolate) complexes and their electrochemical behavior in the presence of CO2

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    A series of Group 13 complexes MLX2 (M = Al or Ga, L = SC6H4-2-PtBu2 or OC6H4-2-PtBu2, X = Me or C6F5) have been synthesized and characterized by multinuclear NMR spectroscopy and single crystal X-ray diffraction. Reactions of Me3Al or Me3Ga with an equivalent of either 2-tBu2P(C6H4)OH (1) or 2-tBu2P(C6H4)SH (5) resulted in the formation of four new (2,3,6, and 7), 4-coordinate dimethyl chelate (S,P or O,P) complexes via methane elimination. The dimethyl gallium complexes (3 and 7) underwent a further reaction with excess B(C6F5)3, and through ligand exchange (methyl/pentafluorophenyl), resulted in the disubstituted bis(pentafluorophenyl) analogs (4 and 8). Cyclic voltammetry (CV) experiments for all compounds in the presence of and the absence of (1–8) CO2 were performed. For compounds showing cathodic reduction waves under CO2 (2,3,4, and 6), bulk electrolysis experiments were performed. Electrochemical studies indicate that, for several compounds, a transient CO2 adduct is formed which undergoes a one-electron, irreversible (or partially irreversible) reduction to form an unstable radical anion

    Cymantrene–Triazole "Click" Products: Structural Characterization and Electrochemical Properties

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    We report the first known examples of triazole-derivatized cymantrene complexes (η5-[4-substituted triazol-1-yl]cyclopentadienyl)tricarbonylmanganese(I), obtained via a “click” chemical synthesis, bearing a phenyl, 3-aminophenyl, or 4-aminophenyl moiety at the 4-position of the triazole ring. Structural characterization data using multinuclear NMR, UV–vis, ATR-IR, and mass spectrometric methods are provided, as well as crystallographic data for (η5-[4-phenyltriazol-1-yl]cyclopentadienyl)tricarbonylmanganese(I) and (η5-[4-(3-aminophenyl)triazol-1-yl]cyclopentadienyl)tricarbonylmanganese(I). Cyclic voltammetric characterization of the redox behavior of each of the three cymantrene–triazole complexes is presented together with digital simulations, in situ infrared spectroelectrochemistry, and DFT calculations to extract the associated kinetic and thermodynamic parameters. The trypanocidal activity of each cymantrene–triazole complex is also examined, and these complexes are found to be more active than cymantrene alone

    Tetrabenzoporphyrin and -mono-, - Cis -di- and tetrabenzotriazaporphyrin derivatives: Electrochemical and spectroscopic implications of meso CH Group replacement with nitrogen

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    Nonperipherally hexyl-substituted metal-free tetrabenzoporphyrin (2H-TBP, 1a) tetrabenzomonoazaporphyrin (2H-TBMAP, 2a), tetrabenzo-cis-diazaporphyrin (2H-TBDAP, 3a), tetrabenzotriazaporphyrin (2H-TBTAP, 4a), and phthalocyanine (2H-Pc, 5a), as well as their copper complexes (1b-5b), were synthesized. As the number of meso nitrogen atoms increases from zero to four, Îmax of the Q-band absorption peak becomes red-shifted by almost 100 nm, and extinction coefficients increased at least threefold. Simultaneously the blue-shifted Soret (UV) band substantially decreased in intensity. These changes were related to the relative electron-density of each macrocycle expressed as the group electronegativity sum of all meso N and CH atom groups, âχR. X-ray photoelectron spectroscopy differentiated between the three different types of macrocyclic nitrogen atoms (the Ninner, (NH)inner, and Nmeso) in the metal-free complexes. Binding energies of the Nmeso and Ninner,Cu atoms in copper chelates could not be resolved. Copper insertion lowered especially the cathodic redox potentials, while all four observed redox processes occurred at larger potentials as the number of meso nitrogens increased. Computational chemical methods using density functional theory confirmed 1b to exhibit a Cu(II) reduction prior to ring-based reductions, while for 2b, Cu(II) reduction is the first reductive step only if the nonperipheral substituents are hydrogen. When they are methyl groups, it is the second reduction process; when they are ethyl, propyl, or hexyl, it becomes the third reductive process. Spectro-electrochemical measurements showed redox processes were associated with a substantial change in intensity of at least two main absorbances (the Q and Soret bands) in the UV spectra of these compounds

    Landslide susceptibility mapping at VAZ watershed (Iran) using an artificial neural network model: a comparison between multilayer perceptron (MLP) and radial basic function (RBF) algorithms

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    Landslide susceptibility and hazard assessments are the most important steps in landslide risk mapping. The main objective of this study was to investigate and compare the results of two artificial neural network (ANN) algorithms, i.e., multilayer perceptron (MLP) and radial basic function (RBF) for spatial prediction of landslide susceptibility in Vaz Watershed, Iran. At first, landslide locations were identified by aerial photographs and field surveys, and a total of 136 landside locations were constructed from various sources. Then the landslide inventory map was randomly split into a training dataset 70 % (95 landslide locations) for training the ANN model and the remaining 30 % (41 landslides locations) was used for validation purpose. Nine landslide conditioning factors such as slope, slope aspect, altitude, land use, lithology, distance from rivers, distance from roads, distance from faults, and rainfall were constructed in geographical information system. In this study, both MLP and RBF algorithms were used in artificial neural network model. The results showed that MLP with Broyden–Fletcher–Goldfarb–Shanno learning algorithm is more efficient than RBF in landslide susceptibility mapping for the study area. Finally the landslide susceptibility maps were validated using the validation data (i.e., 30 % landslide location data that was not used during the model construction) using area under the curve (AUC) method. The success rate curve showed that the area under the curve for RBF and MLP was 0.9085 (90.85 %) and 0.9193 (91.93 %) accuracy, respectively. Similarly, the validation result showed that the area under the curve for MLP and RBF models were 0.881 (88.1 %) and 0.8724 (87.24 %), respectively. The results of this study showed that landslide susceptibility mapping in the Vaz Watershed of Iran using the ANN approach is viable and can be used for land use planning

    Rate-Dependent Nucleation and Growth of NaO2 in Na-O2 Batteries

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    Understanding the oxygen reduction reaction kinetics in the presence of Na ions and the formation mechanism of discharge product(s) is key to enhancing Na–O2 battery performance. Here we show NaO2 as the only discharge product from Na–O2 cells with carbon nanotubes in 1,2-dimethoxyethane from X-ray diffraction and Raman spectroscopy. Sodium peroxide dihydrate was not detected in the discharged electrode with up to 6000 ppm of H2O added to the electrolyte, but it was detected with ambient air exposure. In addition, we show that the sizes and distributions of NaO2 can be highly dependent on the discharge rate, and we discuss the formation mechanisms responsible for this rate dependence. Micron-sized (∼500 nm) and nanometer-scale (∼50 nm) cubes were found on the top and bottom of a carbon nanotube (CNT) carpet electrode and along CNT sidewalls at 10 mA/g, while only micron-scale cubes (∼2 μm) were found on the top and bottom of the CNT carpet at 1000 mA/g, respectively.Seventh Framework Programme (European Commission) (Marie Curie International Outgoing Fellowship, 2007-2013))National Science Foundation (U.S.) (MRSEC Program, award number DMR-0819762)Robert Bosch GmbH (Bosch Energy Research Network (BERN) Grant)China Clean Energy Research Center-Clean Vehicles Consortium (CERC-CVC) (award number DE-PI0000012)Skolkovo Institute of Science and Technology (Skoltech-MIT Center for Electochemical Energy Storage

    Landslide susceptibility mapping using support vector machine and GIS at the Golestan province, Iran

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    The main goal of this study is to produce landslide susceptibility map using GIS-based support vector machine (SVM) at Kalaleh Township area of the Golestan province, Iran. In this paper, six different types of kernel classifiers such as linear, polynomial degree of 2, polynomial degree of 3, polynomial degree of 4, radial basis function (RBF) and sigmoid were used for landslide susceptibility mapping. At the first stage of the study, landslide locations were identified by aerial photographs and field surveys, and a total of 82 landslide locations were extracted from various sources. Of this, 75% of the landslides (61 landslide locations) are used as training dataset and the rest was used as (21 landslide locations) the validation dataset. Fourteen input data layers were employed as landslide conditioning factors in the landslide susceptibility modelling. These factors are slope degree, slope aspect, altitude, plan curvature, profile curvature, tangential curvature, surface area ratio (SAR), lithology, land use, distance from faults, distance from rivers, distance from roads, topographic wetness index (TWI) and stream power index (SPI). Using these conditioning factors, landslide susceptibility indices were calculated using support vector machine by employing six types of kernel function classifiers. Subsequently, the results were plotted in ArcGIS and six landslide susceptibility maps were produced. Then, using the success rate and the prediction rate methods, the validation process was performed by comparing the existing landslide data with the six landslide susceptibility maps. The validation results showed that success rates for six types of kernel models varied from 79% to 87%. Similarly, results of prediction rates showed that RBF (85%) and polynomial degree of 3 (83%) models performed slightly better than other types of kernel (polynomial degree of 2 = 78%, sigmoid = 78%, polynomial degree of 4 = 78%, and linear = 77%) models. Based on our results, the differences in the rates (success and prediction) of the six models are not really significant. So, the produced susceptibility maps will be useful for general land-use planning
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