Galaxy candidates in the Zone of Avoidance     

Ofer Lahav  Noah Brosch  Evgeny Goldberg  George K. T. Hau  Renée C. Kraan-Korteweg  & Andy J. Loan 《Monthly notices of the Royal Astronomical Society》1998,299(1):24-30

Motivated by recent discoveries of nearby galaxies in the Zone of Avoidance (ZOA), we conducted a pilot study of galaxy candidates at low galactic latitude, near galactic longitude l  ∼ 135°, where the Supergalactic plane is crossed by the Galactic plane. We observed with the 1-m Wise Observatory in the l band 17 of the 'promising' candidates identified by visual examination of Palomar red plates by Hau et al. A few candidates were also observed in R or B bands, or had spectroscopic observations performed at the Isaac Newton Telescope and at the Wise Observatory. Our study suggests that there are probably 10 galaxies in this sample. We also identify a probable planetary nebula. The final confirmation of the nature of these sources must await the availability of full spectroscopic information. The success rate of ∼ 50 per cent in identifying galaxies at galactic latitude | b | < 5° indicates that the ZOA is a promising region to discover new galaxies.  相似文献   

Geophysical evidence for gas geohazards off Iskenderun Bay, SE Turkey     

Ana García-García  Daniel L. Orange  Norman M. Maher  Adam S. Heffernan  Gary S. Fortier  Andy Malone 《Marine and Petroleum Geology》2004,21(10):1255-1264

High-resolution seafloor and sub-surface data were acquired as part of a site survey in Iskenderun Bay, SE Turkey to characterize the geohazards at the location of the proposed drilling site. A 3 km×3 km geophysical study reveals a pockmark field which trends NE and NNE, similar to the trend of major fault systems in the area. The pockmarks, with an average diameter of 35 m, reach their highest density in the northern part of the detailed survey area, with 13 features/km². Acoustic anomalies in the seismic records (acoustic turbidity, blanking, enhanced reflectors) below the proposed drilling site indicated potential shallow gas beneath it. The local seismic anomalies (amplitude and frequency) parallel to stratigraphy were assigned a low gas risk. As a result of the active neotectonics in the area, the pockmark field presented a potential hazard for drilling at the original location. The geohazard study resulted in moving the proposed drilling site eastward to an area of fewer pockmarks, less sub-surface seismic anomalies, and thus a location interpreted as a lower geohazard environment.  相似文献   

Depositional history of peatland pines (Pinus sylvestris L.) in NW Enontekiö, Finnish Lapland: implications for Middle Holocene drought and temperature fluctuations     

Samuli Helama  Hannu Herva  Joonas Uusitalo  Andy Moir  Kari Mielikäinen  Pekka Nöjd  Markku Oinonen  Raimo Sutinen 《Boreas: An International Journal of Quaternary Research》2023,52(3):427-439

High altitude and latitude findings of subfossil peatland pine trees were unearthed from the region of NW Finnish Lapland and dated by ¹⁴C and tree-ring methods. The depositional history of the trees illustrated two distinct peatland pine phases dated to Middle Holocene intervals 4900–4400 and 4100–3400 cal. a BC. It seems evident that both thermal and hydroclimatic fluctuations have played roles of varying importance in the establishment of this pine population and its demise. The presence of these pines, from a site ~60 km north of the coniferous timberline and conditions ~1 °C and 100 degree-days colder than those at the present-day timberline, concurs with previous studies demonstrating the association between the high-latitude summer-temperature cooling and circumpolar timberline retreat since the Middle Holocene due to Milankovitch forcing. On the other hand, the peatland pine recruitment was made possible by drier than present surface conditions during the previously reconstructed Middle Holocene drought anomaly (Hyvärinen-Alhonen event). Our data suggest this event was not continuous but reached its two-phase climax during the peatland pine phases, with an interruption of several centuries with moister surface conditions between 4400 and 4100 cal. a BC. The findings highlight the sensitivity of well-dated peatland tree assemblages in terms of recording past climatic evolution and events and the need for new collections from north and south Fennoscandia and the Baltic region, for more detailed analyses over extended time intervals and regions.  相似文献   

Dissolved and total organic and inorganic carbon in some British rivers   总被引：2，自引：0，他引：2  

Andy Baker  Sue Cumberland  Naomi Hudson 《Area》2008,40(1):117-127

Rivers transport both organic and inorganic carbon from their sources to the sea. Results of ~800 organic and inorganic analyses from various British rivers of contrasting size and land use are presented here: (1) the headwater River Tern, a rural river of 852 km² catchment; (2) the Ouseburn, a small urban 55 km² catchment; (3) the River Tyne, a larger river system of ~3000 km² catchment; (4) a spatial survey from 205 sample sites on ~60 rivers from SW England. We found that, with the exception of peat-rich headwaters, DIC concentration is always greater than DOC. DIC is primarily in the form HCO₃ ⁻ , with DIC concentrations highest in highly urbanised catchments, typically greater than those observed in catchments with carbonate bedrock, demonstrating a significant and previously unrecognised anthropogenic inorganic carbon input to urban rivers.  相似文献   

Seismic evidence for a sharp lithospheric base persisting to the lowermost mantle beneath the Caribbean     

Tadashi Kito  Christine Thomas  reas Rietbrock  Edward J. Garnero  Stuart E. J. Nippress  Andy E. Heath 《Geophysical Journal International》2008,174(3):1019-1028

Broad-band data from South American earthquakes recorded by Californian seismic networks are analysed using a newly developed seismic wave migration method—the slowness backazimuth weighted migration (SBWM). Using the SBWM, out-of-plane seismic P -wave reflections have been observed. The reflection locations extend throughout the Earth's lower mantle, down to the core–mantle boundary (CMB) and coincide with the edges of tomographically mapped high seismic velocities. Modelling using synthetic seismograms suggests that a narrow (10–15 km) low- or high-velocity lamella with about 2 per cent velocity contrast can reproduce the observed reflected waveforms, but other explanations may exist. Considering the reflection locations and synthetic modelling, the observed out-of-plane energy is well explained by underside reflections off a sharp reflector at the base of the subducted lithosphere. We also detect weaker reflections corresponding to the tomographically mapped top of the slab, which may arise from the boundary between the Nazca plate and the overlying former basaltic oceanic crust. The joint interpretation of the waveform modelling and geodynamic considerations indicate mass flux of the former oceanic lithosphere and basaltic crust across the 660 km discontinuity, linking processes and structure at the top and bottom of the Earth's mantle, supporting the idea of whole mantle convection.  相似文献   

The fifteenth Mallet–Milne lecture     

Andy Campbell 《Bulletin of Earthquake Engineering》2016,14(5):1333-1336

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Keeping privatization on track: the active state, the unwilling investor and the case of rail freight in the UK     

Andy Cumbers  John Farrington 《Area》2000,32(2):157-167

Summary This paper presents a case study of rail freight privatization in the UK within the context of wider debates about globalization, the neo-liberal privatization programme and the role of the state. The case study reveals the interventionist role played by the state in both legitimizing the process of privatization and selling the idea to a reluctant private sector at home and abroad. In doing so, it points to a number of contradictions and problems in the model of privatization chosen that raises larger questions about the process of economic liberalization and market deregulation.  相似文献   

Value of Geologically Derived Features in Machine Learning Facies Classification     

Halotel  Julie  Demyanov  Vasily  Gardiner  Andy 《Mathematical Geosciences》2020,52(1):5-29

Mathematical Geosciences - The aim of this work is to demonstrate how geologically interpretative features can improve machine learning facies classification with uncertainty assessment. Manual...  相似文献   

The impact of ditch blocking on the hydrological functioning of blanket peatlands   总被引：1，自引：0，他引：1       下载免费PDF全文

Joseph Holden  Sophie M. Green  Andy J. Baird  Richard P. Grayson  Gemma P. Dooling  Pippa J. Chapman  Christopher D. Evans  Mike Peacock  Graeme Swindles 《水文研究》2017,31(3):525-539

Ditch blocking in blanket peatlands is common as part of peatland restoration. The effects of ditch blocking on flow regimes and nearby water tables were examined in a field trial. After an initial 6‐month monitoring period, eight ditches had peat dams installed 10 m apart along their entire length (dammed), four of these ditches were also partially infilled through bank reprofiling (reprofiled). Four ditches were left open with no dams or reprofiling (open). These 12 ditches and the surrounding peat were monitored for 4 more years. An initial five‐fold reduction in discharge occurred in the dammed and the reprofiled ditches with the displaced water being diverted to overland flow and pathways away from the ditches. However, there was a gradual change over time in ditch flow regime in subsequent years, with the overall volume of water leaving the dammed and the reprofiled ditches increasing per unit of rainfall to around twice that which occurred in the first year after blocking. Hence, monitoring for greater than one year is important for understanding hydrological impacts of peatland restoration. Overland flow and flow in the upper ~4 cm of peat was common and occurred in the inter‐ditch areas for over half of the time after ditch blocking. There was strong evidence that topographic boundaries of small ditch catchments, despite being defined using a high‐resolution Light Detection And Ranging‐based terrain model, were not always equivalent to actual catchment areas. Hence, caution is needed when upscaling area‐based fluxes, such as aquatic carbon fluxes, from smaller scale studies including those using ditches and small streams. The effect of ditch blocking on local water tables was spatially highly variable but small overall (time‐weighted mean effect <2 cm). Practitioners seeking to raise water tables through peatland restoration should first be informed either by prior measurement of water tables or by spatial modelling to show whether the peatland already has shallow water tables or whether there are locations that could potentially undergo large water‐table recoveries.  相似文献   

Comparison of the luminescence properties of waters depositing flowstone and stalagmites at Lower Cave,Bristol     

Andy Baker  William L. Barnes 《水文研究》1998,12(9):1447-1459

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