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| Registros recuperados: 428 | |
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| Guanjun Shen; Xing Gao; Bin Gao; Darryl Granger. |
| The chronological position of Peking Man, or Homo erectus pekinensis, has long been pursued, but has remained problematic due to lack of a suitable dating method^1-7^. Here we report cosmogenic ^26^Al/ ^10^Be burial dating of quartz sediments and artifacts from the lower strata of Zhoukoudian Locality 1 where the remains of early members of the Peking Man family were discovered. This study marks the first radioisotopic dating of any early hominin site in China beyond the range of mass spectrometric U-series dating. The weighted mean of six meaningful measurements, 0.75 +/-; 0.09 (0.11) Ma (million years), provides the best age estimate for lower cultural Layers ^7-10^. Together with previously reported U-series^3^ and paleomagnetic^4^ data, as well as... |
| Tipo: Manuscript |
Palavras-chave: Earth & Environment. |
| Ano: 2008 |
URL: http://precedings.nature.com/documents/2275/version/1 |
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| Andrey V. Zhuravlev; Yadviga A. Vevel. |
| Three-dimension modeling of fossils is one of the branches of computer using in palaeontology. The branch has wide perspectives but it is hardly developed, especially in micropalaeontology. Proposed method of 3D modelling of microfossils demands no unique and expansive equipment and can be realized practically in any palaeontological laboratory. Lower accuracy of the models developed is not critical for most the fields of their utilization: for teaching purposes, construction of illustrated databases and virtual atlases, and for the display of microfossils to a general audience. |
| Tipo: Manuscript |
Palavras-chave: Earth & Environment. |
| Ano: 2008 |
URL: http://precedings.nature.com/documents/1632/version/1 |
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| Michael E. Baker; David J. Chang; Charlie Chandsawangbhuwana. |
| Lamprey, a basal vertebrate, contains orthologs of the estrogen receptor (ER), progesterone receptor and corticoid receptor. A perplexing property of lamprey is that 15[alpha]-hydroxy-steroids are active steroids. For example, 15[alpha]-hydroxy-estradiol [15[alpha]-OH-E2] is the estrogen, instead of estradiol (E2). To investigate how 15[alpha]-OH-E2 binds lamprey ER, we constructed a 3D model of the lamprey ER with E2 and 15[alpha]-OH-E2. Our 3D model shows that S[delta] on Met-409 can form a hydrogen bond with the 15[alpha]-hydroxyl on 15[alpha]-OH-E2. In human ER[alpha], the corresponding residue Ile-424 has a van der Waals contact with 15[alpha]-OH-E2. BLAST analysis of GenBank indicates that among vertebrate ERs, only lamprey ER contains a... |
| Tipo: Manuscript |
Palavras-chave: Developmental Biology; Ecology; Earth & Environment. |
| Ano: 2009 |
URL: http://precedings.nature.com/documents/2768/version/1 |
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| Fucheng Zhang; Zhonghe Zhou; Xing Xu; Xiaolin Wang; Corwin Sullivan. |
| Recent coelurosaurian discoveries have greatly enriched our knowledge of the dinosaur-bird transition, but all reported taxa close to this transition are from relatively well-known coelurosaurian groups^1-3^. Here we report a new basal avialan, Epidexipteryx hui gen. et sp. nov., from the Middle-Late Jurassic of Inner Mongolia, China. This new species is characterized by an unexpected combination of characters seen in several different theropod groups, particularly the Oviraptorosauria. Phylogenetic analysis shows it to be the sister taxon to Epidendrosaurus^4,5^, forming a new clade at the base of Avialae^6^. Epidexipteryx also possesses two pairs of elongate ribbon-like tail feathers (ETFs), and its limbs lack contour feathers for flight. This finding... |
| Tipo: Manuscript |
Palavras-chave: Developmental Biology; Ecology; Earth & Environment. |
| Ano: 2008 |
URL: http://precedings.nature.com/documents/2326/version/1 |
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| Nicholas J. Gales; Phillip J. Clapham; C. Scott Baker. |
| During the austral summer of 2007/08, hunting of Southern Hemisphere (SH) humpback whales will recommence after almost half a century of protection. The stated rationale for this hunt, by the Government of Japan (GoJ), is to gather important scientific information for use in management. If the scientific need were defensible, and the proponents had accommodated reasonable conservation concerns, then criticisms of the hunt would be limited to philosophical issues. This is not the case. The program’s research objectives are unlikely to be achieved by lethal methods and do not address the principal research needs for SH humpback whales identified by the International Whaling Commission (IWC). |
| Tipo: Manuscript |
Palavras-chave: Earth & Environment. |
| Ano: 2007 |
URL: http://precedings.nature.com/documents/1313/version/1 |
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| Sierra Rayne; Kaya Forest. |
| New experimental data is available in the literature regarding the octanol-water distribution behavior of representative straight chain perfluoroalkyl carboxylate (PFCA) and sulfonate (PFSA) congeners. The current study provides the first investigation into the predictive ability of various software programs for estimating the corresponding octanol-water partitioning (log P) and distribution (log D) constants of PFCAs and PFSAs. Wide predictive variation was found within and between the various methods. Several programs were able to accurately estimate the log P/D fragmental contributions of a -CF~2~- group for PFCAs, as well as the associated Gibbs free energies for partitioning into octanol from water due to the hydrophobic character of the... |
| Tipo: Manuscript |
Palavras-chave: Chemistry; Earth & Environment. |
| Ano: 2009 |
URL: http://precedings.nature.com/documents/3282/version/1 |
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| Sierra Rayne; Kaya Forest. |
| New experimental data is available in the literature regarding the octanol-water distribution behavior of representative straight chain perfluoroalkyl carboxylate (PFCA) and sulfonate (PFSA) congeners. The current study provides the first investigation into the predictive ability of various software programs for estimating the corresponding octanol-water partitioning (log P) and distribution (log D) constants of PFCAs and PFSAs. Wide predictive variation was found within and between the various methods. Several programs were able to accurately estimate the log P/D fragmental contributions of a -CF~2~- group for PFCAs, as well as the associated Gibbs free energies for partitioning into octanol from water due to the hydrophobic character of the... |
| Tipo: Manuscript |
Palavras-chave: Chemistry; Earth & Environment. |
| Ano: 2009 |
URL: http://precedings.nature.com/documents/3282/version/2 |
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| John C. Rodda; Max A. Little; Harvey J. E. Rodda; Patrick E. McSharry. |
| During the 1960s, a study was made of the magnitude, frequency and distribution of intense rainfall over the UK, employing data from more than 120 daily-read rain gauges covering the period 1911 to 1960. Using the same methodology, that study was recently updated utilizing data for the period 1961 to 2006 for the same gauges, or from those nearby. This paper describes the techniques applied to ensure consistency of data and statistical modelling. It presents a comparison of patterns of extreme rainfalls for the two periods and discusses the changes that have taken place. Most noticeably, increases up to 20% have occurred in the north west of the country and in parts of East Anglia. There have also been changes in other areas, including decreases of the... |
| Tipo: Manuscript |
Palavras-chave: Earth & Environment. |
| Ano: 2009 |
URL: http://precedings.nature.com/documents/3847/version/1 |
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| Mark Conyers. |
| Standard texts dutifully list 16 essential elements for plant growth, yet the literature indicates that the boundary between essential and nonessential nutrients for plants is not always clear. When animals and 'lower' organisms are considered, the team of 16 is considerably expanded and the notion of essentiality is blurred. Why are some elements more important than others to plants and to organisms in general? Here I propose three criteria by which elements might have been selected in the development of organisms: low atomic weight, at least modest abundance, and ease of assembly into complex structures. Assembly of the structural elements C, N, S, P, and O is based on valency and ionic potential. The selection of monovalent elements... |
| Tipo: Manuscript |
Palavras-chave: Earth & Environment; Evolutionary Biology. |
| Ano: 2009 |
URL: http://precedings.nature.com/documents/3223/version/1 |
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| Aaron W. Baum; Tadeusz Patzek; Martin Bender; Steve Renich; Wes Jackson. |
| An understanding of agriculture's energy, material, and labor requirements is essential for achieving economic and ecological sustainability, and for assessing the effectiveness of relevant policy decisions (biofuel subsidies, regulations, labeling, etc.). Previous studies of energy, materials, and labor use in farming have been based on either unverified voluntary reporting or test plots, rather than on the high-resolution measurements of mass and energy flows. Here we present a recursive analysis of 1.25 million data points describing in unprecedented detail the resource transactions on a 60 ha farm functioning for over 6 years. This analysis highlights the importance of accounting for all types of materials, as well as capital equipment,... |
| Tipo: Manuscript |
Palavras-chave: Ecology; Earth & Environment. |
| Ano: 2010 |
URL: http://precedings.nature.com/documents/4291/version/1 |
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| David Goldberg; Angela L. Slagle. |
| In recent years, the debate over the most effective means to stabilize greenhouse gas concentrations in the atmosphere has endorsed multiple approaches and a variety of technologies. Assuring secure storage of anthropogenic carbon dioxide is one of our most pressing global scientific challenges that may contribute to achieving a stable solution over the next several decades. Geological sequestration by injection into deep-sea basalt formations provides unique and significant advantages over other potential storage options, including: (a) vast reservoir capacities with high porosity and permeability, sufficient to accommodate centuries-long U.S. production of fossil fuel CO~2~ at locations within a few hundreds of kilometers of populated areas; (b) chemical... |
| Tipo: Poster |
Palavras-chave: Earth & Environment. |
| Ano: 2008 |
URL: http://precedings.nature.com/documents/2640/version/1 |
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| Sierra Rayne; Kaya Forest. |
| A hydrometric analysis over the available historical record (1973-2010) was conducted for the Moose Jaw River station near Burdick in south-central Saskatchewan, Canada. Frequency analyses on mean monthly, average annual, monthly minimum/maximum, and annual minimum flows generally yielded poor fits, and problems with negative flow predictions for mid- to long-term return periods regardless of distribution type. The annual maximum streamflow time series is reasonably well-described by linear and log Pearson Type III distributions, although both distribution types underestimate extreme maximum flows. Mann-Kendall linear time series analysis on mean monthly and annual streamflows reveals no trend in annual water yields, nor in mean monthly flows between March... |
| Tipo: Poster |
Palavras-chave: Earth & Environment. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/6697/version/1 |
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| Sierra Rayne; Kaya Forest. |
| A long-term analysis of temporal trends and frequency analyses for temperatures (1913-2010), precipitation (1909-2010), and wind speed (1954-1996) was conducted on the Moose Jaw climate station in south-central Saskatchewan, Canada. Average annual and springtime temperatures are increasing over time, as are daily mean temperatures during March. Mean daily maximum temperatures are increasing on an annual basis and during the spring period, whereas mean daily minimum temperatures are increasing during February, March, August, and September, as well as on an annual basis and during spring and summer. There are significant positive time trends for growing degree days base 8C (GDD~8~) and 10C (GDD~10~). Rainfall has been increasing during March as well as... |
| Tipo: Poster |
Palavras-chave: Earth & Environment. |
| Ano: 2011 |
URL: http://precedings.nature.com/documents/6703/version/1 |
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| Saheeb Ahmed Kayani. |
| In this research report, X-ray diffraction (XRD) and X-ray fluorescence (XRF) spectrometry have been used to determine the mineralogical and elemental composition of a stone sample recovered from a location near village Lehri in district Jhelum, Pakistan. The test data is compared with previous findings (as reported in literature and included in references) to identify this sample stone as part of a prehistoric meteorite ablation debris.
Further to this, carbon content of a specimen of the meteorite debris has been determined through combustion analysis. This carbon abundance has been compared with carbon wt% value of a certain type of meteorites to establish the origin and nature of the parent body of this particular meteorite debris. |
| Tipo: Manuscript |
Palavras-chave: Chemistry; Earth & Environment. |
| Ano: 2010 |
URL: http://precedings.nature.com/documents/5450/version/1 |
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| Xiaoqing Su. |
| Mosquito causes problems in both disease transmission and disturbance to people's daily life. The controlling methods used now are mainly application of chemical pesticides which result in serious harm to environment. Biological control of the pest is one of the ideal ways. But, lack of suitable agent makes it difficult to extend this technique in wider scope. _Pythium guiyangense_ Su is a newly found fungal pathogen of mosquitoes and is promising for practical use. Here we summarize a list of mosquitoes that can be infected by the fungus so far, which shows the potential significance of the application of the fungus in the future. |
| Tipo: Manuscript |
Palavras-chave: Microbiology; Earth & Environment. |
| Ano: 2008 |
URL: http://precedings.nature.com/documents/1875/version/1 |
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| Registros recuperados: 428 | |
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