Mock galaxy redshift catalogues from simulations: implications for Pan-STARRS1     

Yan-Chuan Cai  Raul E. Angulo  Carlton M. Baugh  Shaun Cole  Carlos S. Frenk  Adrian Jenkins 《Monthly notices of the Royal Astronomical Society》2009,395(3):1185-1203

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Deep sea immunity: unveiling immune constituents from the hydrothermal vent mussel Bathymodiolus azoricus     

Bettencourt R  Roch P  Stefanni S  Rosa D  Colaço A  Santos RS 《Marine environmental research》2007,64(2):108-127

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Rainfall spatial organization and areal reduction factors in the metropolitan area of Barcelona (Spain)     

Raul Rodríguez  Xavier Navarro  M. Carmen Casas  Angel Redaño 《Theoretical and Applied Climatology》2013,114(1-2):1-8

The rainfall spatial organization in the metropolitan area of Barcelona (Spain) has been studied from records of an urban rain gauge network in the period 1994–2009. Using statistical and regional analysis techniques, correlation between data recorded by the different rain gauges has been calculated, and the effective number of independent stations (n _eq) equivalent to the used network has been determined. It has been found out that for durations longer than 20 min, the areal rainfall return period observed for a storm registered by the network approximately decreases by a factor of 1/n _eq in relation to the current point rainfall intensity–duration–frequency relationships for the metropolitan area of Barcelona. Using objective analysis techniques, continuous precipitation fields have been generated on a regular grid with a spatial resolution of 300?×?300 m for the storms registered by the rain gauges from 1994 to 2009, for durations from 10 min to 24 h. The precipitation fields obtained have been useful to estimate the characteristic areal reduction factors in the metropolitan area of Barcelona. A direct relationship has been found between the areal reduction factor for all the area corresponding to the urban rainfall network of Barcelona and the effective number of n _eq for every duration considered.  相似文献   

Ionospheric error contribution to GNSS single-frequency navigation at the 2014 solar maximum     

Raul Orus Perez 《Journal of Geodesy》2017,91(4):397-407

For single-frequency users of the global satellite navigation system (GNSS), one of the main error contributors is the ionospheric delay, which impacts the received signals. As is well-known, GPS and Galileo transmit global models to correct the ionospheric delay, while the international GNSS service (IGS) computes precise post-process global ionospheric maps (GIM) that are considered reference ionospheres. Moreover, accurate ionospheric maps have been recently introduced, which allow for the fast convergence of the real-time precise point position (PPP) globally. Therefore, testing of the ionospheric models is a key issue for code-based single-frequency users, which constitute the main user segment. Therefore, the testing proposed in this paper is straightforward and uses the PPP modeling applied to single- and dual-frequency code observations worldwide for 2014. The usage of PPP modeling allows us to quantify—for dual-frequency users—the degradation of the navigation solutions caused by noise and multipath with respect to the different ionospheric modeling solutions, and allows us, in turn, to obtain an independent assessment of the ionospheric models. Compared to the dual-frequency solutions, the GPS and Galileo ionospheric models present worse global performance, with horizontal root mean square (RMS) differences of 1.04 and 0.49 m and vertical RMS differences of 0.83 and 0.40 m, respectively. While very precise global ionospheric models can improve the dual-frequency solution globally, resulting in a horizontal RMS difference of 0.60 m and a vertical RMS difference of 0.74 m, they exhibit a strong dependence on the geographical location and ionospheric activity.  相似文献   

Using geographically weighted regression kriging for crop yield mapping in West Africa     

Muhammad Imran  Alfred Stein  Raul Zurita-Milla 《International journal of geographical information science》2013,27(2):234-257

Geographical information systems support the application of statistical techniques to map spatially referenced crop data. To do this in the optimal way, errors and uncertainties have to be minimized that are often associated with operations on the data. This paper applies a spatial statistical approach to upscale crop yields from the field level toward the scale of Burkina Faso. Observed yields were related to the Normalized Difference Vegetation Index derived from SPOT-VEGETATION. The objective was to quantify the uncertainties at the subsequent steps. First, we applied a point pattern analysis to examine uncertainties due to the sampling network of field surveys in the country. Second, geographically weighted regression kriging (GWRK) was applied to upscale the yield observations and to quantify the corresponding uncertainty. The proposed method was demonstrated with the mapping of sorghum yields in Burkina Faso and results were compared with those from regression kriging (RK) and kriging with external drift using a local kriging neighborhood (KEDLN). The proposed method was validated with independent yield observations obtained from field surveys. We observed that the lower uncertainty range value increased by 39%, and the upper uncertainty range value decreased by 51%, when comparing GWRK with RK and KEDLN. Moreover, GWRK reduced the prediction error variance as compared to RK (20 vs. 31) and to KEDLN (20 vs. 39). We found that climate and topography had a major impact on the country’s sorghum yields. Further, the financial ability of farmers influenced the crop management and, thus, the sorghum crop yields. We concluded that GWRK effectively utilized information present in the covariate datasets and improved the accuracies of both the regional-scale mapping of sorghum yields and was able to quantify the associated uncertainty.  相似文献   

Galactosynthesis predictions at high redshift     

Ari Buchalter  Raul Jimenez  Marc Kamionkowski 《Monthly notices of the Royal Astronomical Society》2001,328(2):520-526

We predict the Tully–Fisher (TF) and surface-brightness–magnitude relations for disc galaxies at     and discuss the origin of these scaling relations and their scatter. We find that both halo dynamics and the star formation history play important roles, and we show that the variation of the TF relation with redshift can be a potentially powerful discriminator of galaxy-formation models. In particular, the TF relation at high redshift might be used to break parameter degeneracies among galactosynthesis models at     , as well as to constrain the redshift distribution of collapsing dark-matter haloes, the star formation history and baryon fraction in the disc and the distribution of halo spins.  相似文献   

The globular cluster kinematics and galaxy dark matter content of NGC 4649 (M60)     

Terry Bridges  Karl Gebhardt  Ray Sharples  Favio Raul Faifer  Juan C. Forte  Michael A. Beasley  Stephen E. Zepf  Duncan A. Forbes  David A. Hanes  Michael Pierce 《Monthly notices of the Royal Astronomical Society》2006,373(1):157-166

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The mass function of the stellar component of galaxies in the Sloan Digital Sky Survey     

Benjamin Panter  Alan F. Heavens  Raul Jimenez 《Monthly notices of the Royal Astronomical Society》2004,355(3):764-768

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Baryonic conversion tree: the global assembly of stars and dark matter in galaxies from the Sloan Digital Sky Survey     

Raul Jimenez  Benjamin Panter  Alan F. Heavens  Licia Verde 《Monthly notices of the Royal Astronomical Society》2005,356(2):495-501

Using the spectroscopic sample of the Sloan Digital Sky Survey Data Release 1 (SDSS DR1), we measure how gas was transformed into stars as a function of time and stellar mass: the baryonic conversion tree (BCT). There is a clear correlation between early star formation activity and present-day stellar mass: the more massive galaxies have formed approximately 80 per cent of their stars at   z > 1  , while for the less massive ones the value is only approximately 20 per cent. By comparing the BCT with the dark matter merger tree, we find indications that star formation efficiency at   z > 1  had to be approximately a factor of two higher than today (∼10 per cent) in galaxies with present-day stellar mass larger than  2 × 10¹¹ M_⊙  , if this early star formation occurred in the main progenitor. Therefore, the λ cold dark matter (LCDM) paradigm can accommodate a large number of red objects. On the other hand, in galaxies with present-day stellar mass less than  10¹¹ M_⊙  , efficient star formation seems to have been triggered at   z ∼ 0.2  . We show that there is a characteristic mass  ( M _*∼ 10¹⁰ M_⊙)  for feedback efficiency (or lack of star formation). For galaxies with masses lower than this, feedback (or star formation suppression) is very efficient while for higher masses it is not. The BCT, determined here for the first time, should be an important observable with which to confront theoretical models of galaxy formation.  相似文献   

Resilience through interlinkage: the green climate fund and climate finance governance     

Megan Bowman  Stephen Minas 《Climate Policy》2019,19(3):342-353

The Green Climate Fund (GCF) is a significant and potentially innovative addition to UNFCCC frameworks for mobilizing increased finance for climate change mitigation and adaptation. Yet the GCF faces challenges of operationalization not only as a relatively new international fund but also as a result of US President Trump’s announcement that the United States would withdraw from the Paris Agreement. Consequently the GCF faces a major reduction in actual funding contributions and also governance challenges at the levels of its Board and the UNFCCC Conference of the Parties (COP), to which it is ultimately accountable. This article analyzes these challenges with reference to the GCF’s internal regulations and its agreements with third parties to demonstrate how exploiting design features of the GCF could strengthen its resilience in the face of such challenges. These features include linkages with UNFCCC constituted bodies, particularly the Technology Mechanism, and enhanced engagement with non-Party stakeholders, especially through its Private Sector Facility. The article posits that deepening GCF interlinkages would increase both the coherence of climate finance governance and the GCF’s ability to contribute to ambitious climate action in uncertain times.

Key policy insights

• The Trump Administration’s purported withdrawal from the Paris Agreement creates challenges for the GCF operating model in three key domains: capitalization, governance and guidance.

• Two emerging innovations could prove crucial in GCF resilience to fulfil its role in Paris Agreement implementation: (1) interlinkages with other UNFCCC bodies, especially the Technology Mechanism; and (2) engagement with non-Party stakeholders, especially private sector actors such as large US investors and financiers.

• There is also an emerging soft role for the GCF as interlocutor between policy-makers and non-Party actors to help bridge the communication divide that often plagues cross-sectoral interactions.

• This role could develop through: (a) the GCF tripartite interface between the Private Sector Facility, Accredited Entities and National Designated Authorities; and (b) strengthened collaborations between the UNFCCC Technical and Financial Mechanisms.

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