Carbon-rich Mira variables: radial velocities and distances     

John W. Menzies  Michael W. Feast  Patricia A. Whitelock 《Monthly notices of the Royal Astronomical Society》2006,369(2):783-790

Optical radial velocities have been measured for 38 C-type Mira variables (C-Miras). These data together with others in the literature are used to study the differences between optical and CO millimetre (mm) observations for C-Miras and the necessary corrections to the optical velocities are derived in order to obtain the true radial velocities of the variables. The difference between absorption and emission-line velocities is also examined. A particularly large difference  (+30 km s ⁻¹)  is found in the case of the Hα line. A catalogue is given of 177 C-Miras with estimated distances and radial velocities. The distances are based on bolometric magnitudes derived in Paper I using South African Astronomical Observatory (SAAO) observations or (for 60 of the stars) using non-SAAO photometry. In the latter case, the necessary transformations to the SAAO system are derived. These data will be used in Paper III to study the kinematics of the C-Miras.  相似文献   

Effects of galaxy interactions in different environments     

M. Sol Alonso  Diego G. Lambas  Patricia Tissera  Georgina Coldwell 《Monthly notices of the Royal Astronomical Society》2006,367(3):1029-1038

We analyse star formation rates (SFRs) derived from photometric and spectroscopic data of galaxies in pairs in different environments using the 2-degree field galaxy redshift survey (2dFGRS) and the Sloan digital sky survey (SDSS). The two samples comprise several thousand pairs, suitable to explore into detail the dependence of star formation activity in pairs on orbital parameters and global environment. We use the projected galaxy density derived from the fifth brightest neighbour of each galaxy, with a convenient luminosity threshold to characterize environment in both surveys in a consistent way. Star formation activity is derived through the η parameter in 2dFGRS and through the SFR normalized to the total mass in stars,  SFR/ M *  , given by Brinchmann et al. in the SDSS-second data release (SDSS-DR2). For both galaxy pair catalogs, the star formation birth rate parameter is a strong function of the global environment and orbital parameters. Our analysis on SDSS pairs confirms previous results found with the 2dFGRS where suitable thresholds for the star formation activity induced by interactions are estimated at a projected distance   r _p= 100  h ⁻¹ kpc  and a relative velocity  Δ V = 350 km s⁻¹  . We observe that galaxy interactions are more effective at triggering important star formation activity in low- and moderate-density environments with respect to the control sample of galaxies without a close companion. Although close pairs have a larger fraction of actively star-forming galaxies, they also exhibit a greater fraction of red galaxies with respect to those systems without a close companion, an effect that may indicate that dust stirred up during encounters could affect colours and, partially, obscure tidally induced star formation.  相似文献   

34th meeting of the international whaling commission: Brighton,UK, 19–24 July 1982     

Patricia Birnie 《Marine Policy》1983,7(1):64-68

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International marine organizations essays on structure and activities: Kamil A. Bekiashev and Vitali V. Serebriakov (translated from the Russian by Vitali V. Serebriakov) Martinus Nijhoff,The Hague, 1981, 578 pp,US$130     

Patricia Birnie 《Marine Policy》1983,7(3):224-226

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Neotectonics and seismicity in southern Patagonia     

Laura Perucca  Patricia Alvarado  Mauro Saez 《Geological Journal》2016,51(4):545-559

Research for evaluation of geologic hazards involving earthquakes and volcanic eruptions in southern Argentina seems to have historically received little attention. Nevertheless, the relatively small work done indicates a Neogene tectonic architecture in the area with capability of generating potential hazardous earthquakes in a growing population region. Seismicity and some morphotectonic evidences of Quaternary activity of the Magallanes–Fagnano left‐lateral fault system in the transform boundary between South America and Scotia plates, are analysed in this paper. This fault system is considered to be an important seismogenic source, responsible for large earthquakes that have occurred in southern Argentina. Some examples from the South and Austral Andean Volcanic Zones are also examined in order to show recent volcanic activity which also generated crustal seismicity. Preliminary hazard estimation clearly shows the presence of both potentially active volcanic centres in southern Patagonia that may also trigger seismicity and the high probability for large crustal earthquake generation. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

Rock-magnetic properties of topsoils and urban dust from Morelia (>800,000 inhabitants), Mexico: Implications for anthropogenic pollution monitoring in Mexico’s medium size cities     

Bertha Aguilar Reyes  Francisco Bautista  Avto Goguitchaichvili  Juan Julio Morales Contreras  Julie Battu  Patricia Quintana Owen  Claire Carvallo 《Geofísica Internacional》2013,52(2):121-133

In this work, we investigate the correlation between some magnetic parameters and the level of contamination by heavy metals in urban soils from Morelia city, western Mexico. The magnetic study was carried out on 98 urban soils samples belonging to distinct land uses. Most of analyzed samples contain ferrimagnetic minerals as the responsible for magnetization, most probably corresponding to the titanomagnetites/ titanomaghemites solid solutions. This is inferred from the susceptibility vs. temperature measurements and the isothermal remanent magnetization (IRM) experiments. These measurements also indicate that most of samples are almost completely saturated before 300 mT. Additionally, the S_-200 values (S_-200 = IRM_-200/ SIRM, where IRM_-200= Back-field of 200 mT after magnetic saturation) are between 0.7 and 1.0, characteristic of low coercivity magnetic minerals. The averaged saturation isothermal remanent magnetization (SIRM) curves can be used as an indicator of pollution level, as these curves show different saturation values according to the level of contamination by heavy metals: Cu, Ni, Cr and Sr. These associations of (titano)magnetite with heavy metals were observed by Scanning Electron Microscope revealing some complex aggregates rather than commonly detected spherules.  相似文献   

Thermal Drying and Alkaline Treatment of Biosolids: Effects on Nitrogen Mineralization     

Jorge Silva‐Leal  Patricia Torres‐Lozada  Yasmin J. Cardoza 《洁净——土壤、空气、水》2013,41(3):298-303

Biosolids from the Cañeveralejo WWTP were dehydrated by filter press and then applied two processes to reduce pathogens (PRP): thermally dried biosolid (TDB) and alkalinized biosolid (AB). Untreated, dehydrated biosolid (DB) was used as a control. We evaluated the impact of thermal drying and alkaline treatments on nitrogen mineralization in these substrates. Moreover, agronomic rates for biosolid applications to sugarcane were estimated for each of the treatments leading to application rates of 35.8, 36.4, and 54.5 t/ha for DB, TDB, and AB, respectively, to meet the nitrogen requirement (200 kg N/ha) for sugarcane cultivation (Saccharum officinarum). The results showed that the biosolid rates used increased the mineral nitrogen content of soils by an average of 93.8 and 439.8 mg/kg for all biosolids and the PRP (thermal drying and alkaline treatment) in biosolids had significant effects on mineralization rate, showing better results for the TDBs.  相似文献   

A comparison of geometric approaches to assessing spatial similarity for GIR     

Patricia Frontiera  John Radke 《International journal of geographical information science》2013,27(3):337-360

This research compares the geographic information retrieval (GIR) performance of a set of logistic regression models with those of five non‐probabilistic methods that compute a spatial similarity score for a query–document pair. All methods are applied to a test collection of queries and documents indexed spatially by two convex conservative geometric approximations: the minimum bounding box (MBB) and the convex hull. In the comparison, the tested logistic regression models outperform, in terms of standard information retrieval recall and precision measures, all of the non‐probabilistic methods. The retrieval performance achieved by the logistic regression models on MBB approximations is similar to that achieved by the use of the non‐probabilistic methods on convex hulls. Although these results are valid only for the test collection used in this study, they suggest that a logistic regression approach to GIR provides an alternative to the use of higher‐quality geometric representations that are more difficult to obtain, implement, and process. Additionally, this research demonstrates the ability of a probabilistic approach to effectively incorporate information about geographic context in the spatial ranking process.  相似文献   

Factors Influencing Water Consumption in Multifamily Housing in Tempe,Arizona     

Elizabeth A. Wentz  Angela J. Wills  Won Kyung Kim  Soe W. Myint  Patricia Gober  Robert C. Balling Jr. 《The Professional geographer》2013,65(3):501-510

Central to the Smart Growth movement is that compact development reduces vehicle miles traveled, carbon emissions, and water use. Empirical efforts to evaluate compact development have examined residential densities but have not distinguished decreasing lot sizes from multifamily apartments as mechanisms for compact development. Efforts to link design features to water use have emphasized single-family at the expense of multifamily housing. This study isolates the determinants of water use in large (more than fifty units) apartment complexes in the city of Tempe, Arizona. In July 2007, per bedroom water use increased with pool area, dishwashers, and in-unit laundry facilities. We are able to explain nearly 50 percent of the variation in water demand with these variables. These results inform public policy for reducing water use in multifamily housing structures, suggesting strategies to construct and market “green” apartment units.  相似文献   

Nitrogen Sources and Rates of Phytoplankton Uptake in Different Regions of Hong Kong Waters in Summer     

Jie Xu  Patricia M. Glibert  Hongbin Liu  Kedong Yin  Xiangcheng Yuan  Mianrun Chen  Paul J. Harrison 《Estuaries and Coasts》2012,35(2):559-571

Phytoplankton uptake rates of ammonium (NH₄ ⁺), nitrate (NO₃ ⁻), and urea were measured at various depths (light levels) in Hong Kong waters during the summer of 2008 using ¹⁵N tracer techniques in order to determine which form of nitrogen (N) supported algal growth. Four regions were sampled, two differentially impacted by Pearl River discharge, one impacted by Hong Kong sewage discharge, and a site beyond these influences. Spatial differences in nutrient concentrations, ratios, and phytoplankton biomass were large. Dissolved nutrient ratios suggested phosphorus (P) limitation throughout the region, largely driven by high N loading from the Pearl River in summer. NH₄ ⁺ and urea made up generally ≥50% of the total N taken up and the f ratio averaged 0.26. Even at the river-impacted site where concentrations of NO₃ ⁻ were >20 μM N, NH₄ ⁺ comprised >60% of the total N uptake. Inhibition experiments demonstrated that NO₃ ⁻ uptake rates were reduced by 40% when NH₄ ⁺ was >5 μM N. The relationship between the total specific uptake rates of N (sum of all measured substrates, V, per hour) and the chlorophyll a-specific rates (micromolars of N per microgram of Chl a per hour) varied spatially with phytoplankton biomass. Highest uptake rates and biomass were observed in southern waters, suggesting that P limitation and other factors (i.e., flushing rate) controlled production inshore and that the unincorporated N (mainly NO₃ ⁻) was transported offshore. These results suggest that, at the beginning of summer, inshore algal blooms are fueled primarily by NH₄ ⁺ and urea, rather than NO₃ ⁻, from the Pearl River discharge. When NH₄ ⁺ and urea are depleted, then NO₃ ⁻ is taken up and can increase the magnitude of the bloom.  相似文献