Intersatellite Link (ISL) application to commercial communications satellites. Volume 1: Executive summary

Science.gov (United States)

Young, S. Lee

1987-01-01

Based on a comprehensive evaluation of the fundamental Intersatellite Link (ISL) systems characteristics, potential applications of ISLs to domestic, regional, and global commercial satellite communications were identified, and their cost-effectiveness and other systems benefits quantified wherever possible. Implementation scenarios for the cost-effective communications satellite systems employing ISLs were developed for the first launch in 1993 to 1994 and widespread use of ISLs in the early 2000's. Critical technology requirements for both the microwave (60 GHz) and optical (0.85 micron) ISL implementations were identified, and their technology development programs, including schedule and cost estimates, were derived.

A positive feedback regulation of ISL-1 in DLBCL but not in pancreatic β-cells

Energy Technology Data Exchange (ETDEWEB)

Zhang, Qiao, E-mail: zhangqiao200824@126.com [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Sciences (Ministry of Education), Peking University, 38 Xueyuan Road, 100191 Beijing (China); Yang, Zhe, E-mail: zheyang@bjmu.edu.cn [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Sciences (Ministry of Education), Peking University, 38 Xueyuan Road, 100191 Beijing (China); Wang, Weiping, E-mail: wwp@bjmu.edu.cn [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Sciences (Ministry of Education), Peking University, 38 Xueyuan Road, 100191 Beijing (China); Guo, Ting, E-mail: luckyguoting@bjmu.edu.cn [Department of Gastrointestinal Translation Research, Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Peking University Cancer Hospital, 52 Fucheng Road, 100142 Beijing (China); Jia, Zhuqing, E-mail: zhuqingjia@126.com [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Sciences (Ministry of Education), Peking University, 38 Xueyuan Road, 100191 Beijing (China); Ma, Kangtao, E-mail: makangtao11@126.com [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Sciences (Ministry of Education), Peking University, 38 Xueyuan Road, 100191 Beijing (China); Zhou, Chunyan, E-mail: chunyanzhou@bjmu.edu.cn [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Key Laboratory of Molecular Cardiovascular Sciences (Ministry of Education), Peking University, 38 Xueyuan Road, 100191 Beijing (China)

2014-07-04

Highlights: • ISL-1 is highly expressed in human pancreatic β-cells and DLBCL. • ISL-1 accelerates the tumorigenesis of DLBCL in vivo. • c-Myc positively regulates ISL-1 expression in DLBCL but not in pancreatic β-cells. • ISL-1 and c-Myc forms an ISL-1/c-Myc transcriptional complex only in DLBCL. • Positive feedback regulation of ISL-1 does not exist in normal pancreatic β-cell. - Abstract: Insulin enhancer binding protein-1 (ISL-1), a LIM-homeodomain transcription factor, has been reported to play essential roles in promoting adult pancreatic β-cells proliferation. Recent studies indicate that ISL-1 may also involve in the occurrence of a variety of tumors. However, whether ISL-1 has any functional effect on tumorigenesis, and what are the differences on ISL-1 function in distinct conditions, are completely unknown. In this study, we found that ISL-1 was highly expressed in human pancreatic β-cells, as well as in diffuse large B cell lymphoma (DLBCL), but to a much less extent in other normal tissues or tumor specimens. Further study revealed that ISL-1 promoted the proliferation of pancreatic β-cells and DLBCL cells, and also accelerated the tumorigenesis of DLBCL in vivo. We also found that ISL-1 could activate c-Myc transcription not only in pancreatic β-cells but also in DLBCL cells. However, a cell-specific feedback regulation was detectable only in DLBCL cells. This auto-regulatory loop was established by the interaction of ISL-1 and c-Myc to form an ISL-1/c-Myc transcriptional complex, and synergistically to promote ISL-1 transcription through binding on the ISL-1 promoter. Taken together, our results demonstrate a positive feedback regulation of ISL-1 in DLBCL but not in pancreatic β-cells, which might result in the functional diversities of ISL-1 in different physiological and pathological processes.

A positive feedback regulation of ISL-1 in DLBCL but not in pancreatic β-cells

International Nuclear Information System (INIS)

Zhang, Qiao; Yang, Zhe; Wang, Weiping; Guo, Ting; Jia, Zhuqing; Ma, Kangtao; Zhou, Chunyan

2014-01-01

Highlights: • ISL-1 is highly expressed in human pancreatic β-cells and DLBCL. • ISL-1 accelerates the tumorigenesis of DLBCL in vivo. • c-Myc positively regulates ISL-1 expression in DLBCL but not in pancreatic β-cells. • ISL-1 and c-Myc forms an ISL-1/c-Myc transcriptional complex only in DLBCL. • Positive feedback regulation of ISL-1 does not exist in normal pancreatic β-cell. - Abstract: Insulin enhancer binding protein-1 (ISL-1), a LIM-homeodomain transcription factor, has been reported to play essential roles in promoting adult pancreatic β-cells proliferation. Recent studies indicate that ISL-1 may also involve in the occurrence of a variety of tumors. However, whether ISL-1 has any functional effect on tumorigenesis, and what are the differences on ISL-1 function in distinct conditions, are completely unknown. In this study, we found that ISL-1 was highly expressed in human pancreatic β-cells, as well as in diffuse large B cell lymphoma (DLBCL), but to a much less extent in other normal tissues or tumor specimens. Further study revealed that ISL-1 promoted the proliferation of pancreatic β-cells and DLBCL cells, and also accelerated the tumorigenesis of DLBCL in vivo. We also found that ISL-1 could activate c-Myc transcription not only in pancreatic β-cells but also in DLBCL cells. However, a cell-specific feedback regulation was detectable only in DLBCL cells. This auto-regulatory loop was established by the interaction of ISL-1 and c-Myc to form an ISL-1/c-Myc transcriptional complex, and synergistically to promote ISL-1 transcription through binding on the ISL-1 promoter. Taken together, our results demonstrate a positive feedback regulation of ISL-1 in DLBCL but not in pancreatic β-cells, which might result in the functional diversities of ISL-1 in different physiological and pathological processes

Intersatellite Link (ISL) application to commercial communications satellites. Volume 2: Technical final report

Science.gov (United States)

Young, S. Lee

1987-01-01

Intersatellite Link (ISL) applications can improve and expand communication satellite services in a number of ways. As the demand for orbital slots within prime regions of the geostationary arc increases, attention is being focused on ISLs as a method to utilize this resource more efficiently and circumvent saturation. Various GEO-to-GEO applications were determined that provide potential benefits over existing communication systems. A set of criteria was developed to assess the potential applications. Intersatellite link models, network system architectures, and payload configurations were developed. For each of the chosen ISL applications, ISL versus non-ISL satellite systems architectures were derived. Both microwave and optical ISL implementation approaches were evaluated for payload sizing and cost analysis. The technological availability for ISL implementations was assessed. Critical subsystems technology areas were identified, and an estamate of the schedule and cost to advance the technology to the requiered state of readiness was made.

Network analysis reveals multiscale controls on streamwater chemistry

Science.gov (United States)

McGuire, Kevin J.; Torgersen, Christian E.; Likens, Gene E.; Buso, Donald C.; Lowe, Winsor H.; Bailey, Scott W.

2014-01-01

By coupling synoptic data from a basin-wide assessment of streamwater chemistry with network-based geostatistical analysis, we show that spatial processes differentially affect biogeochemical condition and pattern across a headwater stream network. We analyzed a high-resolution dataset consisting of 664 water samples collected every 100 m throughout 32 tributaries in an entire fifth-order stream network. These samples were analyzed for an exhaustive suite of chemical constituents. The fine grain and broad extent of this study design allowed us to quantify spatial patterns over a range of scales by using empirical semivariograms that explicitly incorporated network topology. Here, we show that spatial structure, as determined by the characteristic shape of the semivariograms, differed both among chemical constituents and by spatial relationship (flow-connected, flow-unconnected, or Euclidean). Spatial structure was apparent at either a single scale or at multiple nested scales, suggesting separate processes operating simultaneously within the stream network and surrounding terrestrial landscape. Expected patterns of spatial dependence for flow-connected relationships (e.g., increasing homogeneity with downstream distance) occurred for some chemical constituents (e.g., dissolved organic carbon, sulfate, and aluminum) but not for others (e.g., nitrate, sodium). By comparing semivariograms for the different chemical constituents and spatial relationships, we were able to separate effects on streamwater chemistry of (i) fine-scale versus broad-scale processes and (ii) in-stream processes versus landscape controls. These findings provide insight on the hierarchical scaling of local, longitudinal, and landscape processes that drive biogeochemical patterns in stream networks.

Network analysis reveals multiscale controls on streamwater chemistry.

Science.gov (United States)

McGuire, Kevin J; Torgersen, Christian E; Likens, Gene E; Buso, Donald C; Lowe, Winsor H; Bailey, Scott W

2014-05-13

By coupling synoptic data from a basin-wide assessment of streamwater chemistry with network-based geostatistical analysis, we show that spatial processes differentially affect biogeochemical condition and pattern across a headwater stream network. We analyzed a high-resolution dataset consisting of 664 water samples collected every 100 m throughout 32 tributaries in an entire fifth-order stream network. These samples were analyzed for an exhaustive suite of chemical constituents. The fine grain and broad extent of this study design allowed us to quantify spatial patterns over a range of scales by using empirical semivariograms that explicitly incorporated network topology. Here, we show that spatial structure, as determined by the characteristic shape of the semivariograms, differed both among chemical constituents and by spatial relationship (flow-connected, flow-unconnected, or Euclidean). Spatial structure was apparent at either a single scale or at multiple nested scales, suggesting separate processes operating simultaneously within the stream network and surrounding terrestrial landscape. Expected patterns of spatial dependence for flow-connected relationships (e.g., increasing homogeneity with downstream distance) occurred for some chemical constituents (e.g., dissolved organic carbon, sulfate, and aluminum) but not for others (e.g., nitrate, sodium). By comparing semivariograms for the different chemical constituents and spatial relationships, we were able to separate effects on streamwater chemistry of (i) fine-scale versus broad-scale processes and (ii) in-stream processes versus landscape controls. These findings provide insight on the hierarchical scaling of local, longitudinal, and landscape processes that drive biogeochemical patterns in stream networks.

Prediction of pollution into ore bearing aquifer from ISL-site

International Nuclear Information System (INIS)

Dolgopolov, V.; Kayukov, P.; Vyatchennikova, L.; Shishkov, I.

2002-01-01

Outcomes of present mineralogical investigations explain some phenomena observed in previous sorption experiences. First of all they elucidate cutback of filtration coefficients of sediments exposed under pollution process as granulometric fractions of these permeable sediments decreased in its weight ratio in according to impermeable ones. Then sorption graphics are explained by chemical and mineralogical changes in experienced substance. Explores made diagnoses and estimation about 45 authigenous and technogenous minerals playing the essential role in the process of mass transfer of uranium and polluted components in ISL-sites. They are considered in all basic fractions of studied sediments. Bright peculiarities are noticed for gravel and coarse sands, which went to pieces as a result of dilution or decomposition of its cement. Mineral composition of clayey fraction also significantly changed after pollution process. Steep lost of weight of fraction 0.005-0.001mm consisted with partial decomposition of clayey minerals basically of montmorillonite. These investigations show also that ones of the main minerals playing such the essential role are sorptive such as silica, silica gel, common opal, opal-CT, noble opal, allophane, montmorillonite and zeolite minerals. In conclusion the given work shows some filtration properties of aquifer in an ISL-site and predicts the spread of a possible pollution for ISL-site to environment. The extension of pollution could be more one-two dimension of affected by ISL-process. The prediction would be exact if the previous investigation included the desorptive characteristics and sorptive data depending on temperature and pressure. Current investigations continued pervious ones after which some inexplicable matters of migration of contaminated halo from an ISL-polygon are as follows: Identification and specification of all minerals outside ISL-polygon; Calculation of mineral balance for contaminated sites; Specification of flow

Do future commercial broadband communication satellites really need laser-communication intersatellite links (ISLs)?

Science.gov (United States)

Freidell, James E.

1997-04-01

Large commercial satellite programs requiring ISLs are growing in number and maturing. An important segment of the commercial satellite market, and its ISL needs, is discussed in the paper. ISL value will increase as long-haul terrestrial backbones become increasingly congested. Providing interregional and intercontinental connectivity via ISL presents far lower cost and fewer problems than relying on terrestrial fiber-optic networks. To demonstrate this, a new metric is proposed which allows 'apples-to- apples' cost/performance comparisons between laser communications in GEO, LEO, and terrestrial fiber-optics. ISL requirements in to the next decade are predicted >= 50-100 Gb/s full duplex. Many attitudinal changes must be embraced among those who choose to focus on this new commercial business. Foremost among these is a preponderance to delivering fully acceptable hardware fast and at low cost, as opposed to merely designing such. Considerable attention must be given business considerations foreign to professionals who have spent time in the government or government contracting sectors. Successful ISL customers will come to recognize that ISLs are not commodity products. Failure to embrace these attitudes will nonetheless constitute decision to which the commercial market, and particularly the financial market, will appropriately respond.

Common variation in ISL1 confers genetic susceptibility for human congenital heart disease.

Directory of Open Access Journals (Sweden)

Kristen N Stevens

Full Text Available Congenital heart disease (CHD is the most common birth abnormality and the etiology is unknown in the overwhelming majority of cases. ISLET1 (ISL1 is a transcription factor that marks cardiac progenitor cells and generates diverse multipotent cardiovascular cell lineages. The fundamental role of ISL1 in cardiac morphogenesis makes this an exceptional candidate gene to consider as a cause of complex congenital heart disease. We evaluated whether genetic variation in ISL1 fits the common variant-common disease hypothesis. A 2-stage case-control study examined 27 polymorphisms mapping to the ISL1 locus in 300 patients with complex congenital heart disease and 2,201 healthy pediatric controls. Eight genic and flanking ISL1 SNPs were significantly associated with complex congenital heart disease. A replication study analyzed these candidate SNPs in 1,044 new cases and 3,934 independent controls and confirmed that genetic variation in ISL1 is associated with risk of non-syndromic congenital heart disease. Our results demonstrate that two different ISL1 haplotypes contribute to risk of CHD in white and black/African American populations.

Groundwater restoration of uranium ISL mines in the United States

International Nuclear Information System (INIS)

Catchpole, G.; Kuchelka, R.

1993-01-01

Although the in-situ leach (ISL) mining of uranium in the US started in the 1960's, the real expansion of this form of mining, which is also called solution mining, took place in the early to mid 1970's in Texas. Some of the early test work used an acid lixiviant but it was soon recognized that, because of environmental considerations, the use of alkaline lixiviants would be preferable to the regulatory agencies and the public. In the past, the two types of alkaline based lixiviants used at US ISL mines were ammonia bicarbonate and sodium bicarbonate. A few ISL mines get by with just adding carbon dioxide to the well field solution. Ammonia bicarbonate is no longer being used today in the US because of the difficulties and expense of restoring the water quality to acceptable standards following mining. This paper briefly describes ISL mining principles and then details procedures and techniques used at USA ISL uranium mines to restore water quality in the mined aquifer. The basic elements are fairly constant but there can be considerable variation in type of water treatment equipment, methods of waste water disposal and use of chemical reducing agents. Three case histories are also presented

S.I. 1987 No.688, The Nuclear Installations (Isle of Man) (Variation) Order 1987

International Nuclear Information System (INIS)

1987-01-01

This Order, which amends the Nuclear Installations (Isle of Man) Order 1977, came into force on 7 May 1987. The Nuclear Installations (Isle of Man) Order 1977 extends certain provisions of the Nuclear Installations Act 1965 as appropriate, to the Isle of Man. This Order extends amendments made to that Act by the Energy Act 1983 and the Congenital Disabilities (Civil Liability) Act 1976, as appropriate, to the Isle of Man. (NEA) [fr

Environmental protection at ISL uranium mining sites in Uzbekistan

International Nuclear Information System (INIS)

Grutsynov, V.A.

2002-01-01

The ecological aspects of uranium mining with particular focus on in situ leaching (ISL) are addressed in the paper. As compared to conventional mining methods, from the ecological point of view, ISL has proved to be advantageous. Innovations developed and introduced in the Navoi Mining and Metallurgical Combinat (NMMC) with the purpose of reducing the impact of the uranium production cycle on the environment are described. (author)

33 CFR 110.179 - Skidaway River, Isle of Hope, Ga.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Skidaway River, Isle of Hope, Ga. 110.179 Section 110.179 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY ANCHORAGES ANCHORAGE REGULATIONS Anchorage Grounds § 110.179 Skidaway River, Isle of Hope, Ga. (a) The...

Functional cardiomyocytes derived from Isl1 cardiac progenitors via Bmp4 stimulation.

Directory of Open Access Journals (Sweden)

Esra Cagavi

Full Text Available As heart failure due to myocardial infarction remains a leading cause of morbidity worldwide, cell-based cardiac regenerative therapy using cardiac progenitor cells (CPCs could provide a potential treatment for the repair of injured myocardium. As adult CPCs may have limitations regarding tissue accessibility and proliferative ability, CPCs derived from embryonic stem cells (ESCs could serve as an unlimited source of cells with high proliferative ability. As one of the CPCs that can be derived from embryonic stem cells, Isl1 expressing cardiac progenitor cells (Isl1-CPCs may serve as a valuable source of cells for cardiac repair due to their high cardiac differentiation potential and authentic cardiac origin. In order to generate an unlimited number of Isl1-CPCs, we used a previously established an ESC line that allows for isolation of Isl1-CPCs by green fluorescent protein (GFP expression that is directed by the mef2c gene, specifically expressed in the Isl1 domain of the anterior heart field. To improve the efficiency of cardiac differentiation of Isl1-CPCs, we studied the role of Bmp4 in cardiogenesis of Isl1-CPCs. We show an inductive role of Bmp directly on cardiac progenitors and its enhancement on early cardiac differentiation of CPCs. Upon induction of Bmp4 to Isl1-CPCs during differentiation, the cTnT+ cardiomyocyte population was enhanced 2.8±0.4 fold for Bmp4 treated CPC cultures compared to that detected for vehicle treated cultures. Both Bmp4 treated and untreated cardiomyocytes exhibit proper electrophysiological and calcium signaling properties. In addition, we observed a significant increase in Tbx5 and Tbx20 expression in differentiation cultures treated with Bmp4 compared to the untreated control, suggesting a link between Bmp4 and Tbx genes which may contribute to the enhanced cardiac differentiation in Bmp4 treated cultures. Collectively these findings suggest a cardiomyogenic role for Bmp4 directly on a pure population of

Streamwater chemistry and nutrient budgets for forested watersheds in New England: variability and management implications

Science.gov (United States)

J.W. Hornbeck; S.W. Bailey; D.C. Buso; J.B. Shanley

1997-01-01

Chemistry of precipitation and streamwater and resulting input-output budgets for nutrient ions were determined concurrently for three years on three upland, forested watersheds located within an 80 km radius in central New England. Chemistry of precipitation and inputs of nutrients via wet deposition were similar among the three watersheds and were generally typical...

Analysis of the Accuracy of Beidou Combined Orbit Determination Enhanced by LEO and ISL

Directory of Open Access Journals (Sweden)

FENG Laiping

2017-05-01

Full Text Available In order to improve the precision of BeiDou orbit determination under the conditions of regional ground monitoring station and make good use of increasingly rich on-board data and upcoming ISL technology, a method of BeiDou precision orbit determination is proposed which combines the use of ground monitoring stations data, low earth orbit satellite(LEOs data and Inter-Satellite Link(ISL data. The effects of assisting data of LEOs and ISL on the precision orbit determination of navigation satellite are discussed. Simulation analysis is carried out mainly from the number of LEOs, orbit slot configuration and ISL. The results show that the orbit precision of BeiDou will greatly improve about 73% with a small number of LEOs, while improvement of clock bias is not remarkable; the uniform orbit slot configuration of the same number of LEOs has a modest effect on the accuracy of combined orbit determination; compared with LEOs, the increase of ISL will significantly improve the accuracy of orbit determination with a higher efficiency.

75 FR 51379 - Safety Zone; Celebrate Erie, Presque Isle Bay, Erie, PA

Science.gov (United States)

2010-08-20

... display. DATES: This rule is effective from 9:30 p.m. until 10:30 p.m. on August 22, 2010. ADDRESSES...: Temporary final rule. SUMMARY: The Coast Guard is establishing a temporary safety zone on Presque Isle Bay... Presque Isle Bay in Erie, PA during the Celebrate Erie fireworks display, August 22, 2010. This temporary...

Trends in precipitation and streamwater chemistry in East Creek watershed in southwestern British Columbia, 1971–2008

Directory of Open Access Journals (Sweden)

Michael C. FELLER

2010-08-01

Full Text Available Bulk precipitation and streamwater in a small, undisturbed, forested watershed in southwestern British Columbia were sampled regularly and analyzed for dissolved chemical constituents from 1971 to 2008. Concentrations and fluxes of most chemicals in precipitation and streamwater have exhibited considerable yearly variation. Temporal trends, when they have occurred, have rarely been consistent for the entire 1972–2008 time period. Precipitation has exhibited a decline in electrical conductivity, a decline in NH4, inorganic-N, and total-N concentrations and fluxes since the 1980s, an increase in pH, a decline in acid H fluxes since ~1990, and a decrease in SO4 concentrations and fluxes from 1980 until the late 1990s. Streamwater has exhibited an increase in NO3 concentrations and fluxes until the late 1990s, an increase in pH and decrease in acid H fluxes since the early 1990s, a decrease in SO4 concentrations and fluxes from ~1980 until ~2000, and increases in Na and Cl concentrations and fluxes until ~2000. Critical precipitation SO4 and inorganic-N loads have probably been exceeded for most years. East Ck. watershed has continuously experienced net inflows of all forms of N and acid H, and net outflows of dissolved Si, Na, Mg, and Ca. Net inflows of inorganic forms of N and total-N have decreased since the early 1980s. Net acid H inflows have decreased since the early 1990s, while net Na and Cl outflows increased until ~2000. The contribution of nutrient cycling processes within the watershed to the changes is currently unknown.

Home radon levels and seasonal correction factors for the Isle of Man

International Nuclear Information System (INIS)

Grainger, P.; Preece, A.W.; Goodfellow, S.A.

2000-01-01

Ionizing radiation dose levels due to home radon can rise to levels that would be illegal for workers in the nuclear industry. It is well known that radon levels within homes and from home to home, and also from month to month, vary considerably. To define an Isle of Man radon seasonal correction factor, readings were taken in eight homes over a 12 month period. An average island indoor exposure of 48 Bq m -3 (range 4-518 Bq m -3 ) was determined from 285 homes selected from a cohort of 1300 families participating in the European Longitudinal Study of Pregnancy and Childhood (ELSPAC) in the Isle of Man. This compares with a UK home average of 20 Bq m -3 and a European Union average (excluding UK) of 68 Bq m -3 . Ten homes of those measured were found to have radon levels above the National Radiological Protection Board 200 Bq m -3 action level. There are 29 377 homes on the Isle of Man, suggesting that there could be some 900 or more homes above the action level. No statistical difference was found between the NRPB and Isle of Man seasonal correction factors. (author)

VT Built Up Lands in Grand Isle County - 1986

Data.gov (United States)

Vermont Center for Geographic Information — (Link to Metadata) NRCS mapped historical and current-day built-up lands for Grand Isle County, VT using several vintages of aerial photography: 1941, 1962, 1974,...

VT Built Up Lands in Grand Isle County - 1941

Data.gov (United States)

Vermont Center for Geographic Information — (Link to Metadata) NRCS mapped historical and current-day built-up lands for Grand Isle County, VT using several vintages of aerial photography: 1941, 1962, 1974,...

Development of Uranium Mining by ISL in Kazakhstan

International Nuclear Information System (INIS)

Demekhov, Yuriy; Gorbatenko, Olga

2014-01-01

In the second half of the 60s, feasibility of Uranium production from low-grade ores by in-situ leaching (ISL) was proved. This radically changed the situation in the raw material base in Kazakhstan. Rapid development of uranium mining by ISL in Kazakhstan caused by factor of availability of large sandstone type uranium deposits. Kazakhstan continuously carries out exploration and prospecting to expand the resource base of uranium. In 2011 and 2012 uranium resources increased by more than 110 thousand tU and 40690 tU was mined. Resource growth is 2.5 times higher than the depleting. Since 2012 Kazatomprom is prospecting for new uranium sandstone deposits in southern Kazakhstan by efforts of Volkovgeologia and at their own expense. The program lasts until 2030. Prior to 2015, allocated more than 20 mils. U.S. dollars in prospecting works. In near future the discovery of new deposits is expected.

Multipotent embryonic isl1+ progenitor cells lead to cardiac, smooth muscle, and endothelial cell diversification.

Science.gov (United States)

Moretti, Alessandra; Caron, Leslie; Nakano, Atsushi; Lam, Jason T; Bernshausen, Alexandra; Chen, Yinhong; Qyang, Yibing; Bu, Lei; Sasaki, Mika; Martin-Puig, Silvia; Sun, Yunfu; Evans, Sylvia M; Laugwitz, Karl-Ludwig; Chien, Kenneth R

2006-12-15

Cardiogenesis requires the generation of endothelial, cardiac, and smooth muscle cells, thought to arise from distinct embryonic precursors. We use genetic fate-mapping studies to document that isl1(+) precursors from the second heart field can generate each of these diverse cardiovascular cell types in vivo. Utilizing embryonic stem (ES) cells, we clonally amplified a cellular hierarchy of isl1(+) cardiovascular progenitors, which resemble the developmental precursors in the embryonic heart. The transcriptional signature of isl1(+)/Nkx2.5(+)/flk1(+) defines a multipotent cardiovascular progenitor, which can give rise to cells of all three lineages. These studies document a developmental paradigm for cardiogenesis, where muscle and endothelial lineage diversification arises from a single cell-level decision of a multipotent isl1(+) cardiovascular progenitor cell (MICP). The discovery of ES cell-derived MICPs suggests a strategy for cardiovascular tissue regeneration via their isolation, renewal, and directed differentiation into specific mature cardiac, pacemaker, smooth muscle, and endothelial cell types.

The Outlook on Potential Uranium ISL Mining at Nyota Deposit (Tanzania)

International Nuclear Information System (INIS)

Boytsov, A.; Stander, S.; Martynenko, V.

2014-01-01

Conclusion: • The Nyota deposit is a world class deposit, which holds over 50Mlb which is potentially amenable to ISR. • Significant resources upside potential. • Initial ISL testing has yielded encouraging results, which should be followed up. • The ISR project is currently at the R&D stage, and the next steps have been identified and planned. • Technical, commercial and SHEQ challenges remains that must be overcome. • Uranium One will continue to investigate the ISR potential via a responsible, toll gated approach. • Successful testing could unlock a new ISL production region.

Pensar o Islão: Questões coloniais, interrogações pós-coloniais

Directory of Open Access Journals (Sweden)

AbdoolKarim Vakil

2012-10-01

Full Text Available O “terrorista islâmico” e os imigrantes e minorias muçulmanas culturalmente “inassimiláveis” representam as duas faces da visão do Islão como “o problema do século XXI” que domina o debate público contemporâneo e a formulação das políticas de Estado nacionais e internacionais nas sociedades ocidentais. A natureza das representações, mais ou menos essencialistas, que informam e deformam estes debates varia consoante os contextos em virtude da relação histórica, em regra colonial, de cada nação com o Islão, das instituições e saberes vocacionados para o seu estudo, e da composição, perfil e peso das comunidades muçulmanas em cada sociedade. Mas a lógica identitária e securitária que configura o discurso do Islão como problema reproduz, redefinidos agora como problemas do multiculturalismo, da governação, da tolerância e da segurança, as mesmas preocupações identitárias e securitárias geradas no contexto colonial. Este artigo apela a uma abordagem desconstrutiva do Islão através da leitura crítica do discurso português.

El fundamentalismo islámico: el caso de Chechenia

OpenAIRE

Botta, Jorge Paulo

2004-01-01

Hablar de Fundamentalismo Islámico se ha convertido en un lugar común en muchos análisis de Seguridad Internacional, sobre todo relacionándolo con el terrorismo internacional y las llamadas nuevas amenazas a la seguridad.

Climatology, storm morphologies, and environments of tornadoes in the British Isles: 1980–2012

OpenAIRE

Mulder, Kelsey J.; Schultz, David M.

2015-01-01

A climatology is developed for tornadoes during 1980–2012 in the British Isles, defined in this article as England, Scotland, Wales, Northern Ireland, Republic of Ireland, Channel Islands, and the Isle of Man. The climatology includes parent storm type, interannual variability, annual and diurnal cycles, intensities, oc- currence of outbreaks (defined as three or more tornadoes in the same day), geographic distribution, and environmental conditions derived from proximity soundings of tornadoe...

Implementing a sustainable clinical supervision model for Isles nurses in Orkney.

Science.gov (United States)

Hall, Ian

2018-03-02

The Isles Network of Care (INOC) community nurses work at the extreme of the remote and rural continuum, working mostly as lone practitioners. Following the development of sustainable clinical supervision model for Isles nurses in Orkney, clinical supervision was found to improve both peer support and governance for this group of isolated staff. A literature overview identified the transition of clinical supervision in general nursing over 24 years from 'carrot' to 'stick'. The study included a questionnaire survey that was sent to the 2017 Queen's Nursing Institute Scotland cohort to elicit information about the nurses' experience of clinical supervision. The survey found that 55% provide supervision and 40% receive it. Health board encouragement of its use was found to be disappointingly low at 40%. The INOC nurses were surveyed about the new peer-support (restorative) model, which relies on video-conference contact to allow face to face interaction between isolated isles nurses. Feedback prompted a review of clinical supervision pairings, and the frequency and methods of meeting. The need for supervisor training led to agreement with the Remote and Rural Health Education Alliance to provide relevant support. The perceived benefits of supervision included increased support and reflection, and improved relationships with isolated colleagues.

El Estado Islámico: Catalizador del irredentismo kurdo.

Directory of Open Access Journals (Sweden)

David Ernesto Garzón García

2017-01-01

Full Text Available Con su aparición, el Estado Islámico se consolida como una amenaza de carácter internacional y se convierte en el elemento pivote de la reestructuración de las relaciones internacionales, la configuración de nuevas alianzas y ciertamente en el impulsor de escenarios anteriormente poco presumibles con relación al Medio Oriente, entre ellos se establece como uno de los componentes catalizadores del irredentismo kurdo y su proyecto estatal e independentista. La reaparición de los kurdos en la esfera internacional potenciada por el estado Islámico, al ser en un principio el único grupo con capacidad de enfrentarlos, genera tensiones en la región pues la consolidación del Kurdistán alteraría la estructura territorial de cuatro Estados particularmente y sus relaciones políticas y comerciales, impactando directamente en la relativa estabilidad que ha imperado en el siglo XXI.

British Isles Field Experience: An Initiative in International Education.

Science.gov (United States)

Martin, William J.

The British Isles Field Experience (BIFE) program was initiated at Williamsport Area Community College (WACC) to provide a group of WACC faculty and staff members with individual and group activities of a personal, professional, and cultural nature in order to promote an international perspective that can be infused into student, collegiate, and…

Rayleigh wave tomography of the British Isles from ambient seismic noise

Science.gov (United States)

Nicolson, Heather; Curtis, Andrew; Baptie, Brian

2014-08-01

We present the first Rayleigh wave group speed maps of the British Isles constructed from ambient seismic noise. The maps also constitute the first surface wave tomography study of the crust under the British Isles at a relatively high resolution. We computed interferometric, interstation Rayleigh waves from vertical component records of ambient seismic noise recorded on 63 broad-band and short-period stations across the UK and Ireland. Group velocity measurements were made from the resulting surface wave dispersion curves between 5 and 25 s using a multiple phase-matched filter method. Uncertainties in the group velocities were computed by calculating the standard deviation of four dispersion curves constructed by stacking a random selection of daily cross-correlations. Where an uncertainty could not be obtained for a ray path using this method, we estimated it as a function of the interreceiver distance. Group velocity maps were computed for 5-25-s period using the Fast Marching forward solution of the eikonal equation and iterative, linearized inversion. At short and intermediate periods, the maps show remarkable agreement with the major geological features of the British Isles including: terrane boundaries in Scotland; regions of late Palaeozoic basement uplift; areas of exposed late Proterozoic/early Palaeozoic rocks in southwest Scotland, northern England and northwest Wales and, sedimentary basins formed during the Mesozoic such as the Irish Sea Basin, the Chester Basin, the Worcester Graben and the Wessex Basin. The maps also show a consistent low-velocity anomaly in the region of the Midlands Platform, a Proterozoic crustal block in the English Midlands. At longer periods, which are sensitive velocities in the lower crustal/upper mantle, the maps suggest that the depth of Moho beneath the British Isles decreases towards the north and west. Areas of fast velocity in the lower crust also coincide with areas thought to be associated with underplating of the

The geologic story of Isle Royale National Park

Science.gov (United States)

Huber, N. King

1975-01-01

Isle Royale is an outstanding example of relatively undisturbed northwoods lake wilderness. But more than simple preservation of such an environment is involved in its inclusion in our National Park System. Its isolation from the mainland provides an almost untouched laboratory for research in the natural sciences, especially those studies whose very nature depends upon such isolation. One excellent example of such research is the intensive study of the predator-prey relationship of the timber wolf and moose, long sponsored by the National Park Service and Purdue University. In probably no other place in North America are the necessary ecological conditions for such a study so admirably fulfilled as on Isle Royale. The development of a natural laboratory with such conditions is ultimately dependent upon geologic processes and events that although not unique in themselves, produced in their interplay a unique result, the island archipelago as we know it today, with its hills and valleys, swamps and bogs the ecological framework of the plant and animal world. Even the most casual visitor can hardly fail to be struck by the fiordlike nature of many of the bays, the chains of fringing islands, the ridge-and-valley topography, and the linear nature of all these features. The distinctive topography of the archipelago is, of course, only the latest manifestation of geologic processes in operation since time immemorial. Fragments of geologic history going back over a billion years can be read from the rocks of the island, and with additional data from other parts of the Lake Superior region, we can fill in some of the story of Isle Royale. After more than a hundred years of study by man, the story is still incomplete. But then, geologic stories are seldom complete, and what we do know allows a deeper appreciation of one of our most naturally preserved parks and whets our curiosity about the missing fragments.

Digitization of uranium deposit information in basin. A new strategy of ISL sandstone-type uranium deposits exploration

International Nuclear Information System (INIS)

Tan Chenglong

2006-01-01

The discovered ISL sandstone-type uranium deposits in the entire world are mostly blind deposits, many of them occur in bleak desert, gobi desert, and semi-hilly land area. Exploration methods for these deposits mainly depend on great and systematic drilling. There are many large-medium size Meso-Cenozoic sedimentary basins in northern China, and over twenty of them are thick overburden basins which are mostly the virgin land for ISL sandstone-type uranium deposit. Due to the comprehensive national power, geological background, uranium exploration ability, great and systematic drilling is not favorable for prospecting ISL sandstone-type uranium deposit in China. According to the exploration and prospecting experiences for mineral ore bodies at home and abroad, uranium information mapping based on geochemical survey of the basins is a new strategy for ISL sandstone-type uranium deposits. It is an economic, practical, fast and effective method, and has been manifested by the performing information digitization for oil and gas resources, gold mineral resources in China and the mapping of uranium information for whole Europe continent. (authors)

Phylogenetic analysis and antifouling potentials of culturable fungi in mangrove sediments from Techeng Isle, China.

Science.gov (United States)

Zhang, Xiao-Yong; Fu, Wen; Chen, Xiao; Yan, Mu-Ting; Huang, Xian-De; Bao, Jie

2018-06-09

To search for more microbial resources for screening environment-friendly antifoulants, we investigated the phylogenetic diversity and antifouling potentials of culturable fungi in mangrove sediments from Techeng Isle, China. A total of 176 isolates belonging to 57 fungal taxa were recovered and identified. The high levels of diversity and abundance of mangrove fungi from Techeng Isle were in accordance with previous studies on fungi from other mangrove ecosystems. Fifteen of the 176 isolates demonstrated high divergence (87-93%) from the known fungal taxa in GenBank. Moreover, 26 isolates recorded in mangrove ecosystems for the first time. These results suggested that mangrove sediments from Techeng Isle harbored some new fungal communities compared with other mangrove ecosystems. The antifouling activity of 57 representative isolates (belonging to 57 different fungal taxa) was tested against three marine bacteria (Loktanella hongkongensis, Micrococcus luteus and Pseudoalteromonas piscida) and two marine macrofoulers (bryozoan Bugula neritina and barnacle Balanus amphitrite). Approximately 40% of the tested isolates displayed distinct antifouling activity. Furthermore, 17 fungal isolates were found to display strong or a wide spectrum of antifouling activity in this study, suggesting that these isolates deserve further study as potential sources of novel antifouling metabolites. To our knowledge, this is the first report on the investigation of the phylogenetic diversity and antifouling potential of culturable fungi in mangrove sediments from Techeng Isle, China. These results contribute to our knowledge of mangrove fungi and further increases the pool of fungi available for natural bioactive product screening.

Some aspects of linacs as applied to the ISL benchmark facility

International Nuclear Information System (INIS)

Shepard, K.W.

1992-01-01

This paper considers several aspects of using linacs in a radioactive beam facility in terms of the Isospin Laboratory (ISL) Benchmark Facility (BMF) plan, described in the 1991 white paper for a possible radioactive-beam laboratory. The intention is not to review comprehensively the application of linacs to an ISL facility, but to compare in outline form several linac options for such a facility. Particular emphasis is given to the use of superconducting rf technology for the secondary beam accelerator. In what follows, first a possible normally-conducting light-ion linac for a primary beam accelerator is briefly outlined. Then the performance and cost of two options for a secondary beam accelerator are compared: a recent design for a normal-conducting cw linac, and an ATLAS-type superconducting linac. Finally, some of the problems which may be encountered at the entrance of a secondary beam linac are discussed

Contemporary Irish identity on the Emerald Isle of the Caribbean

DEFF Research Database (Denmark)

McAtackney, Laura; Ryzewski, Krysta; Cherry, John F

2014-01-01

In recent decades, the island of Montserrat has been noticeably repositioning itself within the Caribbean as a place with a unique Irish heritage. Using the tag-line ‘the Emerald Isle of the Caribbean’, there has been an explicit attempt to evoke images of a verdant, green island with a long Irish...

3D visualisation of a Jurassic oolitic system with GPR data, Isle of Portland (UK)

DEFF Research Database (Denmark)

Moreau, Julien; Hansen, Trine Lykke; Nielsen, Lars

architecture to be the result of mixed hydrodynamic conditions associated with wave activity and tidal currents. The Isle shows a island barrier complex which migrates basinwards but also expands laterally, filling up the available space and cannibalising itself. More proximal facies are effectively observed...... in the north of the Isle towards the former continent or lagoon. However, the survey clearly shows that the shore zone progrades broadly towards the SW, partially away from the Channel, with an obtuse angle compared to former reconstructions. This result suggests that the oolitic shore zone system forms...

Nichols Ranch ISL Uranium Mine - A case history

International Nuclear Information System (INIS)

Catchpole, G.; Thomas, G.

2014-01-01

The Nichols Ranch ISL Uranium Mine is located in the Powder River Basin of Wyoming, U.S.A. The mine is owned and operated by Uranerz Energy Corporation (Uranerz), a U.S. corporation headquartered in Casper, Wyoming. Nichols Ranch started operations in February 2014 and is the newest uranium mine to go into production in the USA. The uranium being extracted is hosted in a sandstone, roll-front deposit at a depth ranging from 400 to 800 feet [~120 to ~240 m). The In-Situ Recovery (ISL) mining method is employed at the Nichols Ranch mine which is the method currently being utilized at most uranium mines in the USA. Environmental permit applications for the Nichols Ranch mine were submitted to the appropriate regulatory agencies in late 2007. It required more than three and a half years to obtain all the necessary permits and licenses to construct and operate the mine. Construction of the mining facilities and the first wellfield started in late 2011 and was completed in late 2013. Mining results to date have been better than anticipated and Uranerz expects to reach its 2014 production target. The most challenging part of getting a new uranium mine in production in the United States of America was the three plus years it took to get through the environmental permitting process. Uranerz was one of three companies in 2011 that applied for permits to construct and operate uranium mines in Wyoming at essentially the same time. The Nichols Ranch mine is licensed to produce up to two million pounds per year of uranium (as U_3O_8) [~770 tU] ready for shipment to the converter. At this time only the ion exchange portion of the central processing plant has been installed at Nichols Ranch with uranium loaded resin being shipped to Cameco’s nearby Smith Ranch – Highland ISL uranium mine for elution, precipitation, drying and packaging under a toll processing agreement. Cameco provides Uranerz with dried and drummed yellowcake that Uranerz owns which is shipped to the

Gaelic language erosion and revitalization on the Isle of Skye, Scotland.

NARCIS (Netherlands)

Smakman, D.; Smith-Christmas, C.; Graaf, de T.; Ostler, N.; Salverda, R.

2008-01-01

This paper analyzes the language loss of three generations of a Gaelic-speaking family located on the Isle of Skye, Scotland. Participants' linguistic skills were assessed via language ability tests. We focused on plurals, passives, and tense, and we examined synthetic forms. The results confirmed

Evaluation of high-frequency mean streamwater transit-time estimates using groundwater age and dissolved silica concentrations in a small forested watershed

Science.gov (United States)

Peters, Norman E.; Burns, Douglas A.; Aulenbach, Brent T.

2014-01-01

Many previous investigations of mean streamwater transit times (MTT) have been limited by an inability to quantify the MTT dynamics. Here, we draw on (1) a linear relation (r 2 = 0.97) between groundwater 3H/3He ages and dissolved silica (Si) concentrations, combined with (2) predicted streamwater Si concentrations from a multiple-regression relation (R 2 = 0.87) to estimate MTT at 5-min intervals for a 23-year time series of streamflow [water year (WY) 1986 through 2008] at the Panola Mountain Research Watershed, Georgia. The time-based average MTT derived from the 5-min data was ~8.4 ± 2.9 years and the volume-weighted (VW) MTT was ~4.7 years for the study period, reflecting the importance of younger runoff water during high flow. The 5-min MTTs are normally distributed and ranged from 0 to 15 years. Monthly VW MTTs averaged 7.0 ± 3.3 years and ranged from 4 to 6 years during winter and 8–10 years during summer. The annual VW MTTs averaged 5.6 ± 2.0 years and ranged from ~5 years during wet years (2003 and 2005) to >10 years during dry years (2002 and 2008). Stormflows are composed of much younger water than baseflows, and although stormflow only occurs ~17 % of the time, this runoff fraction contributed 39 % of the runoff during the 23-year study period. Combining the 23-year VW MTT (including stormflow) with the annual average baseflow for the period (~212 mm) indicates that active groundwater storage is ~1,000 mm. However, the groundwater storage ranged from 1,040 to 1,950 mm using WY baseflow and WY VW MTT. The approach described herein may be applicable to other watersheds underlain by granitoid bedrock, where weathering is the dominant control on Si concentrations in soils, groundwater, and streamwater.

Isl1 expression at the venous pole identifies a novel role for the second heart field in cardiac development.

Science.gov (United States)

Snarr, Brian S; O'Neal, Jessica L; Chintalapudi, Mastan R; Wirrig, Elaine E; Phelps, Aimee L; Kubalak, Steven W; Wessels, Andy

2007-11-09

The right ventricle and outflow tract of the developing heart are derived from mesodermal progenitor cells from the second heart field (SHF). SHF cells have been characterized by expression of the transcription factor Islet-1 (Isl1). Although Isl1 expression has also been reported in the venous pole, the specific contribution of the SHF to this part of the heart is unknown. Here we show that Isl1 is strongly expressed in the dorsal mesenchymal protrusion (DMP), a non-endocardially-derived mesenchymal structure involved in atrioventricular septation. We further demonstrate that abnormal development of the SHF-derived DMP is associated with the pathogenesis of atrioventricular septal defects. These results identify a novel role for the SHF.

Sequence variation at the phenylalanine hydroxylase gene in the British Isles

Energy Technology Data Exchange (ETDEWEB)

Tyfield, L.A. [Southmead Hospital, Bristol (United Kingdom)]|[Univ. of Bristol (United Kingdom); Stephenson, A. [Southmead Hospital, Bristol (United Kingdom); Cockburn, F. [Royal Hospital for Sick Children, Glasgow (United Kingdom)] [and others

1997-02-01

Using mutation and haplotype analysis, we have examined the phenylalanine hydroxylase gene in the phenylketonuria populations of four geographical areas of the British Isles: the west of Scotland, southern Wales, and southwestern and southeastern England. The enormous genetic diversity of this locus within the British Isles is demonstrated in the large number of different mutations characterized and in the variety of genetic backgrounds on which individual mutations are found. Allele frequencies of the more common mutations exhibited significant nonrandom distribution in a north/south differentiation. Differences between the west of Scotland and southwestern England may be related to different events in the recent and past histories of their respective populations. Similarities between southern Wales and southeastern England are likely to reflect the heterogeneity that is seen in and around two large capital cities. Finally, comparison with more recently colonized areas of the world corroborates the genealogical origin by range expansion of several mutations. 38 refs., 2 tabs.

Kontekstualisasi Makna Ukhuwwah Islâmîyah perspektif Jemaah Tarekat Shatarîyah di Nganjuk Jawa Timur

Directory of Open Access Journals (Sweden)

Warsito Warsito

2015-10-01

Full Text Available This article discusses the symbols, process, and meaning of ukhuwwah islâmîyah (Islamic brotherhood within perspective of the followers of the Tarekat Shatârîyah in Tanjunganom Nganjuk East Java. The result of the research indicates that the making process of ukhuwwah islâmîyah has been initiated through bayʻah towards murshid (Guru Wasîtah. To the followers of the Tarekat Shatarîyah, murshid is a person who becomes the main symbol that unites them. Intensity of interaction and meetings have also played significant role in the creation process of ukhuwwah islâmîyah among the adherents the Tarekat. When they gather, they perform a number of rituals such as performing qiyâm al-layl and dhikr and reciting what so-called muji wali kutub. They also discuss various problems of religious and social issues. The making process of ukhuwwah islâmîyah is also convoyed with the use and carrying out of certain symbol and ritual such as wearing the Malakîyah ring and reciting Asmâ’ 9. To the followers of this Tarekat, ukhuwwah islâmîyah means a brotherhood which is founded merely on the spirit of pure intention without any inclination to gain worldly benefits. To them it is a relation which is established on the basis of obedience upon Guru Wasîtah in order to create an eternal brotherhood for the sake of God regardless of their social status.

Preliminary clinical results with the ISL laser

Science.gov (United States)

Hoppeler, Thomas; Gloor, Balder

1992-08-01

The ISL laser (Intelligent Surgical Lasers, Inc.), a Nd:YLF picosecond pulse laser, is currently being used under investigational device exemption to perform microsurgery of the anterior segment of the eye. At different study sites procedures for cataract fragmentation and iridotomy, as well as for posterior capsulotomy after cataract surgery, are under evaluation. Other potential applications include: sclerostomy ab interno, the cutting of membranes in the anterior and posterior segment of the eye; corneal incisions; and corneal intrastromal effects. We discuss various clinically relevant aspects of the use of this picosecond laser. An overview of different computer controlled laser patterns is given.

Uma Reflexão do Islã na Mídia Brasileira: Televisão e Mundo Muçulmano, 2001-2002

OpenAIRE

Cesar Henrique de Queiroz Porto

2012-01-01

Esta tese consiste em um estudo das representações do islã, de árabes e muçulmanos veiculadas pela telenovela O Clone. Seu objetivo principal é verificar como a novela levou a cultura islâmica para a televisão na conjuntura do imediato pós 11 de setembro de 2001. Utilizando como fonte principal o discurso presente na telenovela, concluímos que O Clone funcionou como um instrumento didático para as audiências, oferecendo informações da cultura e religião islâmica em um momento em que essa trad...

Telenovela e Islã: dos estereótipos à visibilidade

Directory of Open Access Journals (Sweden)

Francirosy Campos Barbosa Ferreira

2015-07-01

Full Text Available O objetivo deste artigo é apresentar reflexões sobre o núcleo muçulmano da telenovela O Clone, que foi exibido entre outubro de 2001 e junho de 2002, na Rede Globo de Televisão, tendo sua reprise iniciada em janeiro de 2011. Telenovela escrita por Gloria Perez autora conhecida pelos temas “étnicos” e de cunho social, tais como, ciganos, muçulmanos, indianos, transplante de órgãos, alcoolismo, imigração ilegal, clonagem humana. O argumento que sustento é que a novela “salvou” a comunidade islâmica brasileira da “invisibilidade” e trouxe para dentro das casas brasileiras um pouco da cultura árabe-islâmica, que embora estereotipados, contribuíram significativamente para revelar à nossa sociedade quem são os muçulmanos e em que eles acreditam. Ao escrever o artigo me deparei com outro tipo de “invisibilidade”, os quase inexistentes trabalhos em antropologia visual que contemplam análise de imagens de telenovelas. Neste sentido, este texto busca contribuir com outros modos de ver a televisão, em particular, a telenovela.

Jung, mandala e arquitetura Islâmica

Directory of Open Access Journals (Sweden)

Rafael Raffaelli

2009-03-01

Full Text Available Este artigo se propõe a refletir sobre as origens do conceito junguiano de mandala. Utiliza-se o relato autobiográfico de Jung, Memórias, Sonhos e Reflexões, e sua obra Psicologia e Alquimia para traçar essa origem. Segundo Barbara Hannah, biógrafa de Jung, uma mesquita no Cairo (Egito foi de importância capital para a formulação desse conceito. Provavelmente esse templo é a Mesquita Ahmad Ibn Tulun. É analisada a relação entre a simbologia arquitetônica islâmica inspirada pelo sufismo e as concepções psicológicas de Jung.

O terror e a mídia: o neoconservadorismo norte-americano e o islã radical

OpenAIRE

Ortunes, Leandro

2013-01-01

Esta dissertação tem como objeto de estudo a construção da imagem do neoconservadorismo norte-americano e do Islã radical na mídia. Através de uma fundamentação teórica sobre os choques culturais e os confrontos armados entre Ocidente e Oriente, mais precisamente entre Estados Unidos e países com grande atuação islâmica na forma de governo; apresentaremos os pontos de divergência e possíveis similaridades destes dois grupos. Com esta fundamentação, observaremos as divergências e as superficia...

An oasis of fertility on a barren island: earthworms at Papadil, Isle of Rum

Science.gov (United States)

K.R. Butt; C.N.  Lowe; Mac Callaham; V.  Nuutinen

2016-01-01

The Isle of Rum, Inner Hebrides, has an impoverished earthworm fauna as the soils are generally acidic and nutrient-poor. Species associated with human habitation are found around deserted crofting settlements subjected to

O poder das palavras e das idéias: o caso do fundamentalismo islâmico

OpenAIRE

Wainberg - PUCRS, Jacques

2008-01-01

Este é um estudo sobre o debate teórico que se estabeleceu em torno da tese do choque civilizacional. Explora o argumento de que a cultura tem sido uma variável desconsiderada e desprezada no exame dos temas sociais e políticos contemporâneos. Explora também a temática do fundamentalismo islâmico desde a perspectiva cognitiva. Mostra as correntes teológicas e a crise interna ao Islã em torno da interpretação de suas fontes sagradas. Por fim, contempla a relevância política do papel que as idé...

Aportaciones del feminismo islámico como feminismo poscolonial para la emancipación de las mujeres musulmanas. Revisión bibliográfica de fuentes

OpenAIRE

Salas Rodríguez, Ana

2012-01-01

Se intentar contrastar las contribuciones del feminismo clásico occidental con el feminismo islámico, haciendo mención a otros movimientos feministas, como el poscolonial, por lo que éste nos puede aportar a la hora de entender mejor aquellos feminismo que, como el islámico, no se encuentran en la órbita del feminismo occidental, sino que incluso tienen planteamientos encontrados. De hecho, el propio feminismo islámico es un feminismo poscolonial.

Highly discrepant proportions of female and male Scandinavian and British Isles ancestry within the isolated population of the Faroe Islands

DEFF Research Database (Denmark)

Als, Thomas D; Jorgensen, Tove H; Børglum, Anders D

2006-01-01

Isles ancestry. In the present study we used 122 new and 19 previously published hypervariable region I sequences of the mitochondrial control region to analyse the genetic diversity of the Faroese population and compare it with other populations in the North Atlantic region. The analyses suggested...... that the Faroese mtDNA pool has been affected by genetic drift, and is among the most homogenous and isolated in the North Atlantic region. This will have implications for attempts to locate genes for complex disorders. To obtain estimates of Scandinavian vs British Isles ancestry proportions, we applied...... a frequency-based admixture approach taking private haplotypes into account by the use of phylogenetic information. While previous studies have suggested an excess of Scandinavian ancestry among the male settlers of the Faroe Islands, the current study indicates an excess of British Isles ancestry among...

El fundamentalismo islámico en la Estrategia de Seguridad Nacional 2013

Directory of Open Access Journals (Sweden)

Patricia Rodríguez

2014-05-01

Full Text Available Pasados ocho años de los atentados del 11 de marzo, la nueva Estrategia Nacional Española no incluye el fundamentalismo islámico de forma explícita como un factor clave que puede afectar a la seguridad y bienestar de España y los españoles. Tampoco la anterior Estrategia de Seguridad Nacional de 2011 lo incluía. La nueva Estrategia admite que España es un objetivo del terrorismo yihadista e incluso reconoce que existen algunos elementos que contribuyen a hacer de España un objetivo del terrorismo internacional, como por ejemplo la consideración de España como parte del mundo islámico. Pero no existe otra referencia a la versión más extrema del Islam, como fuente de riesgos y amenazas, tratándose de un país que ha sufrido los perores ataques en Europa, con 191 muertos, y donde la policía ha logrado desarticular 30 células yihadistas en la última década.

Public islam and the common good O islão público e o bem comum

Directory of Open Access Journals (Sweden)

Dale F. Eickelman

2006-05-01

Full Text Available The article discusses the historical and contemporary emergence of a sense of an Islamic public in a variety of Muslim majority societies and elsewhere. These manifestations of public Islam facilitate discussions concerning how to define the common good, equitable solutions to collective problems, shifting boundaries of inclusion and exclusion, and practices that encourage the emergence of a public Islam. Compared to notions of public sphere developed within Western social theory, the article shows that the public sphere is no prerogative of Western modern societies nor of democratic political systems. The study demonstrates that also semi-formal and informal articulations of Muslim identities can facilitate the emergence of public, and therefore accountable, forms of Islam.Este artigo discute a emergência histórica de um sentido de público islâmico em várias sociedades de maioria muçulmana e outras. Estas manifestações de Islão público facilitam as discussões sobre a definição do bem comum, as soluções equitativas para problemas colectivos, a fluidez das fronteiras de inclusão e exclusão e ainda as práticas que encorajam o aparecimento de um Islão público. Comparando com as noções de espaço público desenvolvidas na teoria social ocidental, este artigo mostra que a esfera pública não é exclusiva das sociedades ocidentais modernas nem de sistemas políticos democráticos. O estudo mostra também como articulações formais e semiformais de identidade muçulmana podem facilitar a emergência de formas públicas e portanto socialmente responsabilizáveis de Islão.

Field Philosophy: Environmental Learning and Moral Development in Isle Royale National Park

Science.gov (United States)

Goralnik, Lissy; Nelson, Michael Paul

2017-01-01

We conducted a qualitative analysis of 5 years of student writing data to understand learning and moral development on a field philosophy course in Isle Royale National Park. We were interested in the connection between physical experiences in the natural world and the way students care about or value nonhuman beings, natural systems, and place.…

Processes controlling the retreat of the Isles Dernieres, a Louisiana barrier-island chain

Science.gov (United States)

Dingler, John R.; Reiss, Thomas E.

1991-01-01

The Isles Dernieres is a low-lying, transgressive barrier-island chain situated about 150 km west of the modern Mississippi delta. Much of the Isles Dernieres consists of highly dissected salt-marsh muds that lie at or slightly above sea level and are covered by a veneer of sand along the shoreline facing the Gulf of Mexico. Maximum berm elevations are generally less than 1.5 m above mean sea level. Since the mid-1800s, the initial island has been fragmented into four islands, and the beach face has retreated landward at a rate of more than 10 m/yr. The dominant processes controlling degradation of the chain are cold fronts that pass through the area several times each year and occasional hurricanes. Beach surveys over a 2-year period on the Isles Dernieres document irreversible beach-face retreat in conjunction with multiple cold fronts and one major hurricane (Gilbert). Although both the hurricane and the cold fronts caused the island to erode, the erosional patterns of the two storm types differed from each other. During the two years, over 60 cold fronts collectively caused about 37 m of beach-face retreat, whereas Gilbert itself produced more than 40 m of retreat. A major difference between the two storm types was in the percentage of washover sand produced by each. Commonly, the cold fronts did not create enough of a storm surge to overtop the berm, so most of the material removed from the beach face must have moved offshore or alongshore. Gilbert, in contrast, inundated the study site, and essentially all the sand removed from the beach face moved to the backshore.

Age, growth, and maturity of round whitefish of the Apostle Islands and Isle Royale Regions, Lake Superior

Science.gov (United States)

Bailey, Merryll M.

1963-01-01

The round whitefish has been of some commercial importance in the upper Great Lakes but production in Lake Superior has generally been small; the United States average was 26,600 pounds for 1929-59. This study is based on 1,173 fish collected in the Apostle Islands in 1958-60 and 103 collected at Isle Royale in 1958 and 1960. The average age of 6.0 years at Isle Royale was concluded to be significantly higher than the mean of 4.2 years in the Apostle Islands. The body-scale relation is a straight line with an intercept of 1.1 inches on the length axis. Weight of Apostle Islands round whitefish captured in several months increased as the 3.22 power of the length. Growth in length was relatively slow; nearly or fully 7 years were required to reach an acceptable commercial length of 14 inches in both the Apostle Islands and at Isle Royale. The calculated weights at the end of the seventh year were 12.6 ounces in the Apostle Islands and 13.8 ounces at Isle Royale. Minimum length at maturity of male round whitefish (7.0-7.4 inches) was less than that of females (8.5-8.9 inches). At age-group II, 11.1 percent of male round whitefish, but only 1.5 percent of the females were mature. All males were mature as age-group V and all females as age-group VI. Males dominated the younger age groups but females were more numerous in the older ones. Estimates of the number of eggs in 37 round whitefish ovaries yielded an average of 5,330 eggs for fish 10.5-17.4 inches long.

Nekton usage in a Caminda Bay Saltmarsh at Grand Isle LA July and October 1998

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — During July and October 1988, a total of 42 samples were collected in salt marsh habitats of the Caminada Bay system near Grand Isle, Louisiana to evaluate the use...

Comparing the Influence of Wildfire and Prescribed Burns on Watershed Nitrogen Biogeochemistry Using 15N Natural Abundance in Terrestrial and Aquatic Ecosystem Components

Science.gov (United States)

Stephan, Kirsten; Kavanagh, Kathleen L.; Koyama, Akihiro

2015-01-01

We evaluated differences in the effects of three low-severity spring prescribed burns and four wildfires on nitrogen (N) biogeochemistry in Rocky Mountain headwater watersheds. We compared paired (burned/unburned) watersheds of four wildfires and three spring prescribed burns for three growing seasons post-fire. To better understand fire effects on the entire watershed ecosystem, we measured N concentrations and δ15N in both the terrestrial and aquatic ecosystems components, i.e., soil, understory plants in upland and riparian areas, streamwater, and in-stream moss. In addition, we measured nitrate reductase activity in foliage of Spiraea betulifolia, a dominant understory species. We found increases of δ15N and N concentrations in both terrestrial and aquatic ecosystem N pools after wildfire, but responses were limited to terrestrial N pools after prescribed burns indicating that N transfer from terrestrial to aquatic ecosystem components did not occur in low-severity prescribed burns. Foliar δ15N differed between wildfire and prescribed burn sites; the δ15N of foliage of upland plants was enriched by 2.9 ‰ (difference between burned and unburned watersheds) in the first two years after wildfire, but only 1.3 ‰ after prescribed burns. In-stream moss δ15N in wildfire-burned watersheds was enriched by 1.3 ‰, but there was no response by moss in prescription-burned watersheds, mirroring patterns of streamwater nitrate concentrations. S. betulifolia showed significantly higher nitrate reductase activity two years after wildfires relative to corresponding unburned watersheds, but no such difference was found after prescribed burns. These responses are consistent with less altered N biogeochemistry after prescribed burns relative to wildfire. We concluded that δ15N values in terrestrial and aquatic plants and streamwater nitrate concentrations after fire can be useful indicators of the magnitude and duration of fire effects and the fate of post

Recovery of soil water, groundwater, and streamwater from acidification at the Swedish integrated monitoring catchments.

Science.gov (United States)

Löfgren, Stefan; Aastrup, Mats; Bringmark, Lage; Hultberg, Hans; Lewin-Pihlblad, Lotta; Lundin, Lars; Karlsson, Gunilla Pihl; Thunholm, Bo

2011-12-01

Recovery from anthropogenic acidification in streams and lakes is well documented across the northern hemisphere. In this study, we use 1996-2009 data from the four Swedish Integrated Monitoring catchments to evaluate how the declining sulfur deposition has affected sulfate, pH, acid neutralizing capacity, ionic strength, aluminum, and dissolved organic carbon in soil water, groundwater and runoff. Differences in recovery rates between catchments, between recharge and discharge areas and between soil water and groundwater are assessed. At the IM sites, atmospheric deposition is the main human impact. The chemical trends were weakly correlated to the sulfur deposition decline. Other factors, such as marine influence and catchment features, seem to be as important. Except for pH and DOC, soil water and groundwater showed similar trends. Discharge areas acted as buffers, dampening the trends in streamwater. Further monitoring and modeling of these hydraulically active sites should be encouraged.

O fundamentalismo islâmico em mutação

OpenAIRE

Goulão, José

2001-01-01

Estará o fundamentalismo islâmico a perder capacidade de intervenção? As suas expressões mais conhecidas, a nível de regimes políticos e de grupos, acusam desgaste; alguns dos seus importantes apoios, que tentaram tirar proveito do fenómeno por razões oportunistas e pontuais, parecem ter identificado parcialmente os riscos de tal política; as respostas graduais de alguns sistemas de poder, inicialmente surpreendidos com a amplitude e a profundidade destes movimentos atípicos, contribuíram par...

Imaging a fossil oolitic system with GPR, insights into the exposures of the Isle of Portland (UK)

Science.gov (United States)

Moreau, Julien; Hansen, Trine L.; Nielsen, Lars

2015-04-01

The Isle of Portland shows exposure of uppermost Jurassic oolitic carbonate all along its coast. The stone of Portland properties are famous as standards for concrete composition, as building material but also for sculpture. As a consequence, the Isle has been quarried intensively for hundreds of years. The regional exposure quality is very high with a potential 3D control. The site has seen generations of geologist trainees coming for field work. The Wessex Basin where the Isle is sitting contains an active petroleum system and the geologists visiting/training there use the carbonates of Portland as an analogue to equivalent Middle-East oil and gas reservoir. Surprisingly, although the site has a tremendous potential to understand the 3D architecture and the sedimentary dynamic of an oolitic system, only punctual observations of logs (1D), sometimes correlated have been published. Several studies place a shore line between the Isle and the continent striking NEE-SWW and facing towards the Channel. Facies changes are attributed to rapid sea-level variations and Walter's Law. We have collected an extensive GPR survey of the same stratigraphic interval (The Portland Freestone). With a total of 99 GPR profiles, we have produced grids on top of most of the coastal cliffs and quarry faces. We have encountered 3 main architectures: 2-m-high bars with steep clinoforms, 10s of metres-wide channels plugged with a variety of organisms and stacked aggrading bundles of multidirectional dunesets. Our dataset does not illustrate any major unconformity which could be attributed to a sharp sea-level drop. We have interpreted our sedimentary architecture to be the result of various hydrodynamic conditions associated with a mix of wave and tide influences. The Isle shows an island barrier complex which progrades into the basin but also expands laterally filling up the available space and cannibalising itself. More proximal facies are effectively observed in the north of the island

The O and H stable isotope composition of freshwaters in the British Isles. 2. Surface waters and groundwater

Directory of Open Access Journals (Sweden)

W. G. Darling

2003-01-01

Full Text Available The utility of stable isotopes as tracers of the water molecule has a long pedigree. The study reported here is part of an attempt to establish a comprehensive isotopic 'baseline' for the British Isles as background data for a range of applications. Part 1 of this study (Darling and Talbot, 2003 considered the isotopic composition of rainfall in Britain and Ireland. The present paper is concerned with the composition of surface waters and groundwater. In isotopic terms, surface waters (other than some upland streams are poorly characterised in the British Isles; their potential variability has yet to be widely used as an aid in hydrological research. In what may be the first study of a major British river, a monthly isotopic record of the upper River Thames during 1998 was obtained. This shows high damping of the isotopic variation compared to that in rainfall over most of the year, though significant fluctuations were seen for the autumn months. Smaller rivers such as the Stour and Darent show a more subdued response to the balance between runoff and baseflow. The relationship between the isotopic composition of rainfall and groundwater is also considered. From a limited database, it appears that whereas Chalk groundwater is a representative mixture of weighted average annual rainfall, for Triassic sandstone groundwater there is a seasonal selection of rainfall biased towards isotopically-depleted winter recharge. This may be primarily the result of physical differences between the infiltration characteristics of rock types, though other factors (vegetation, glacial history could be involved. In the main, however, groundwaters appear to be representative of bulk rainfall within an error band of 0.5‰ δ18O. Contour maps of the δ18O and δ2H content of recent groundwaters in the British Isles show a fundamental SW-NE depletion effect modified by topography. The range of measured values, while much smaller than those for rainfall, still covers

Characterization of prehistoric pottery from the Tremiti Isles by trace elements determination

International Nuclear Information System (INIS)

Brandone, A.; Fumo, P.; Giacco, M.; Oddone, M.; Riganti, V.; Baldi, M

1993-01-01

The potteries found on the Tremiti Isles (Italy, Adriatic Sea) have been characterized through their trace elements content. The goal of the work was to find out the number of ore deposits that supplied the clay used to manufacture the pottery. Neutron activation analysis has been employed for trace elements content determinations; the results have been statistically evaluated, clusterized and discussed. (author) 13 refs.; 1 fig.; 3 tabs

75 FR 76688 - Drawbridge Operation Regulation; Isle of Wight (Sinepuxent) Bay, Ocean City, MD

Science.gov (United States)

2010-12-09

..., mile 0.5, at Ocean City, with a vertical clearance of 13 feet above mean high tide in the closed...-AA09 Drawbridge Operation Regulation; Isle of Wight (Sinepuxent) Bay, Ocean City, MD AGENCY: Coast... Ocean City, MD. This proposed rule will require any mariner requesting an opening in the evening hours...

A smart city application: a fully controlled street lighting isle based on Raspberry-Pi card, a ZigBee sensor network and WiMAX.

Science.gov (United States)

Leccese, Fabio; Cagnetti, Marco; Trinca, Daniele

2014-12-18

A smart city application has been realized and tested. It is a fully remote controlled isle of lamp posts based on new technologies. It has been designed and organized in different hierarchical layers, which perform local activities to physically control the lamp posts and transmit information with another for remote control. Locally, each lamp post uses an electronic card for management and a ZigBee tlc network transmits data to a central control unit, which manages the whole isle. The central unit is realized with a Raspberry-Pi control card due to its good computing performance at very low price. Finally, a WiMAX connection was tested and used to remotely control the smart grid, thus overcoming the distance limitations of commercial Wi-Fi networks. The isle has been realized and tested for some months in the field.

A Smart City Application: A Fully Controlled Street Lighting Isle Based on Raspberry-Pi Card, a ZigBee Sensor Network and WiMAX

Directory of Open Access Journals (Sweden)

Fabio Leccese

2014-12-01

Full Text Available A smart city application has been realized and tested. It is a fully remote controlled isle of lamp posts based on new technologies. It has been designed and organized in different hierarchical layers, which perform local activities to physically control the lamp posts and transmit information with another for remote control. Locally, each lamp post uses an electronic card for management and a ZigBee tlc network transmits data to a central control unit, which manages the whole isle. The central unit is realized with a Raspberry-Pi control card due to its good computing performance at very low price. Finally, a WiMAX connection was tested and used to remotely control the smart grid, thus overcoming the distance limitations of commercial Wi-Fi networks. The isle has been realized and tested for some months in the field.

Rising air and stream-water temperatures in Chesapeake Bay region, USA

Science.gov (United States)

Rice, Karen C.; Jastram, John D.

2015-01-01

Monthly mean air temperature (AT) at 85 sites and instantaneous stream-water temperature (WT) at 129 sites for 1960–2010 are examined for the mid-Atlantic region, USA. Temperature anomalies for two periods, 1961–1985 and 1985–2010, relative to the climate normal period of 1971–2000, indicate that the latter period was statistically significantly warmer than the former for both mean AT and WT. Statistically significant temporal trends across the region of 0.023 °C per year for AT and 0.028 °C per year for WT are detected using simple linear regression. Sensitivity analyses show that the irregularly sampled WT data are appropriate for trend analyses, resulting in conservative estimates of trend magnitude. Relations between 190 landscape factors and significant trends in AT-WT relations are examined using principal components analysis. Measures of major dams and deciduous forest are correlated with WT increasing slower than AT, whereas agriculture in the absence of major dams is correlated with WT increasing faster than AT. Increasing WT trends are detected despite increasing trends in streamflow in the northern part of the study area. Continued warming of contributing streams to Chesapeake Bay likely will result in shifts in distributions of aquatic biota and contribute to worsened eutrophic conditions in the bay and its estuaries.

4th Isle of Thorns Conference

CERN Document Server

Hirschfeld, J; Jungnickel, D; Thas, J

2001-01-01

When? These are the proceedings of Finite Geometries, the Fourth Isle of Thorns Conference, which took place from Sunday 16 to Friday 21 July, 2000. It was organised by the editors of this volume. The Third Conference in 1990 was published as Advances in Finite Geometries and Designs by Oxford University Press and the Second Conference in 1980 was published as Finite Geometries and Designs by Cambridge University Press. The main speakers were A. R. Calderbank, P. J. Cameron, C. E. Praeger, B. Schmidt, H. Van Maldeghem. There were 64 participants and 42 contributions, all listed at the end of the volume. Conference web site http://www. maths. susx. ac. uk/Staff/JWPH/ Why? This collection of 21 articles describes the latest research and current state of the art in the following inter-linked areas: • combinatorial structures in finite projective and affine spaces, also known as Galois geometries, in which combinatorial objects such as blocking sets, spreads and partial spreads, ovoids, arcs and caps, as well a...

Prototype Si microstrip sensors for the CDF-II ISL detector

CERN Document Server

Hara, K; Kanao, K; Kim, S; Ogasawara, M; Ohsugi, T; Shimojima, M; Takikawa, K

1999-01-01

Prototype Si microstrip sensors for the CDF-II ISL were fabricated by Hamamatsu Photonics and SEIKO Instruments using 4'' technology. The sensor is AC coupled and double-sided forming a stereo angle of 1.207 degree sign . The strip pitch is 112 mu m on both sides. The main differences between the two manufacturers lie on the technologies of passivation and the structure of coupling capacitors. We describe the design of the sensor and evaluation results of the performance. The evaluations include the total and individual strip currents and interstrip capacitance measured before and after sup 6 sup 0 Co gamma irradiation. (author)

78 FR 34575 - Safety Zone; Bay Swim VI, Presque Isle Bay, Erie, PA

Science.gov (United States)

2013-06-10

... June 22, 2013, a large scale swimming event will be held on Presque Isle Bay near the Erie Yacht Club...'48.82'' W and extend in a straight line 1,000 feet wide to the Erie Yacht Club at position 42[deg]07... wide to the Erie Yacht Club at position 42[deg]07'21.74'' N, 80[deg]07'58.30'' W. (NAD 83) (b...

Acid-rain induced changes in streamwater quality during storms on Catoctin Mountain, Maryland

Science.gov (United States)

Rice, Karen C.; Bricker, O.P.

1992-01-01

Catoctin Mountain receives some of the most acidic (lowest pH) rain in the United States. In 1990, the U.S. Geological Survey (USGS), in cooperation with the Maryland Department of the Environment (MDE) and the Maryland Department of Natural Resources (DNR), began a study of the effects of acid rain on the quality of streamwater on the part of Catoctin Mountain within Cunningham Falls State Park, Maryland (fig. 1). Samples of precipitation collected on the mountain by the USGS since 1982 have been analyzed for acidity and concentration of chemical constituents. During 1982-91, the volume-weighted average pH of precipitation was 4.2. (Volume weighting corrects for the effect of acids being washed out of the atmosphere at the beginning of rainfall). The pH value is measured on a logarithmic scale, which means that for each whole number change, the acidity changes by a factor of 10. Thus rain with a pH of 4.2 is more than 10 times as acidic as uncontaminated rain, which has a pH of about 5.6. The acidity of rain during several rainstorms on Catoctin Mountain was more than 100 times more acidic than uncontaminated rain.

O Sufismo como dimensão mística do Islã

Directory of Open Access Journals (Sweden)

Carlos Frederico Barboza de Souza

2009-05-01

Full Text Available Diante da realidade islâmica contemporânea e buscando estar atento às diversas vozes presentes no “outro”, este artigo tem em vista apresentar de forma sucinta o que é o Sufismo, pensando-o como uma possibilidade – entre muitas – de concretização das crenças islâmicas. Para tal, iniciar-se-á procurando compreender como a notícia acerca de sua existência chega ao Ocidente, ou seja, como os ocidentais o “descobrem”. A seguir, centrar-se-á na busca de compreender o Sufismo a partir de sua relação com o islamismo por meio de suas fontes primordiais: o Corão e o Profeta Muhammad. Por fim, este artigo apresentará brevemente alguns elementos que compõem e caracterizam o repertório de crenças e práticas de várias escolas Sufis tais como a busca da Unicidade Divina, a prática meditativa da recitação dos Nomes Divinos e a submissão à orientação de um “šayh”.Palavras-chave: Sufismo; Mística islâmica; Orientalismo ABSTRACTIn the face of the contemporary Islamic reality and seeking to be attentive to the diversity of voices that we can find in the “other”, this article aims to show briefly what Sufism is, thinking it as a possibility – amongst many – of the realization of the Islamic faith. To articulate this, the article will begin looking at understanding of how the news about its existence arrives in the West, that is, how westerners “discover” it. Then, the article will focus on the search to understand Sufism from its relationship with Islam through its primordial origins: the Koran and the Prophet Muhammad. Finally, this article will look briefly at some elements that make up and characterize the repertory of beliefs and practices of several Sufi schools, such as the search for the Divine Unicity, the meditative practice of the recitation of the Divine Names and the submission to a Šayh orientation.Key words: Sufism; Mystical Islamism; Orientalism.

Dating of streamwater using tritium in a post nuclear bomb pulse world: continuous variation of mean transit time with streamflow

Directory of Open Access Journals (Sweden)

U. Morgenstern

2010-11-01

Full Text Available Tritium measurements of streamwater draining the Toenepi catchment, a small dairy farming area in Waikato, New Zealand, have shown that the mean transit time of the water varies with the flow rate of the stream. Mean transit times through the catchment are 2–5 years during high baseflow conditions in winter, increasing to 30–40 years as baseflow decreases in summer, and then dramatically older water during drought conditions with mean transit time of more than 100 years. Older water is gained in the lower reaches of the stream, compared to younger water in the headwater catchment. The groundwater store supplying baseflow was estimated from the mean transit time and average baseflow to be 15.4 × 10⁶ m³ of water, about 1 m water equivalent over the catchment and 2.3 times total annual streamflow. Nitrate is relatively high at higher flow rates in winter, but is low at times of low flow with old water. This reflects both lower nitrate loading in the catchment several decades ago as compared to current intensive dairy farming, and denitrification processes occurring in the older groundwater. Silica, leached from the aquifer material and accumulating in the water in proportion to contact time, is high at times of low streamflow with old water. There was a good correlation between silica concentration and streamwater age, which potentially allows silica concentrations to be used as a proxy for age when calibrated by tritium measurements. This study shows that tritium dating of stream water is possible with single tritium measurements now that bomb-test tritium has effectively disappeared from hydrological systems in New Zealand, without the need for time-series data.

Production and Electrical Characterization Tests of the ISL Detector and a Trigger Design for Higgs Boson Searches at CDF

Energy Technology Data Exchange (ETDEWEB)

Munar Ara, Antoni [Valencia U.

2002-01-01

This thesis is structured as follows: Chapter 1. gives a brief review of the Higgs mechanism in the Standard Model and the electroweak symmetry breaking. The Standard Model Higgs boson phenomenology at Tevatron energies is reviewed. Chapter 2. describes the upgraded Fermilab laboratory accelerator complex, and the upgraded CDF detector. Chapter 3. gives a brief overview of the more relevant aspects of the silicon detectors, and the ISL is described in detail. Chapter 4. describes the construction of the ISL ladders, the full custom testing setup (functionality tests, laser test, burn-in test and $\\beta$-source measurements), and the problems encountered during the ISL ladders construction. The procedures for ladder grading are also discussed. Chapter 5. describes the multilevel trigger system of the CDF detector, and the trigger primitives available at each level. The most relevant offine event observables are briefly discussed. In Chapter 6 the procedures to estimate the trigger rate and trigger effciency calculation are described. The particularities of triggering in $p\\bar{p}$ collisions at high luminosities are discussed. Chapter 7. and Chapter 8. are dedicated to study an effcient trigger strategy for the $H + W/Z \\to b\\bar{b}jj$ channel and the $H + Z \\to b\\bar{b} \

Creation and (Representation of Historical Discourse in Isle of Passion by Laura Restrepo

Directory of Open Access Journals (Sweden)

Daniela Melis

2011-06-01

Full Text Available Published in Colombia in 1989, but neglected until the author’s later distinction, Laura Restrepo’s first novel, Isle of Passion , focuses on historical facts, as well as on the issues that arise when the impact of events is articulated in official discourse. This study—drawing from Walter Mignolo’s idea of decolonial theory—explores how Restrepo’s attempt to rewrite history following “an-other logic, an-other language, an-other thinking” contributes to the decolonization of knowledge, being, community interests, and cultural heritage. The novel’s plot centers on a minor event in international history: the territorial dispute over the island of Clipperton, which was encountered by an English pirate escaping the Spaniards in the 1700’s, claimed by the Mexicans for its geographical proximity, owned (since 1930 by the French, and occasionally disputed by the English and US governments. Writing while personally experiencing the trauma of exile, Restrepo narrates the forgotten story of the Mexican soldiers—deployed with their families to defend the island—as a metaphor of marginalization. Clipperton, therefore, represents not only a geographical, but also a historical entity. This reading of Isle of Passion describes how its creative dis-order recovers a chapter of national history, finally retold by its silenced protagonists.

Piloting a local dental network across Hampshire and Isle of Wight Primary Care Trusts.

Science.gov (United States)

John, J H; Easterby-Smith, V; Percival, K R

2014-09-01

To pilot a local dental network (LDN) within the Hampshire and Isle of Wight region. An LDN Coordinating Group was set up, which was chaired by the local consultant in dental public health and included representatives from dental commissioning and performance management teams, dental practice advisory team, finance, Oxford and Wessex Dental Deanery and the Hampshire and Isle of Wight Local Dental Committee. The LDN successfully led the organisation of a leadership training course for local dentists, and produced recommendations for local oral surgery and orthodontics care pathways. Key to the success was the collaboration achieved between the commissioners, local postgraduate dental deanery and local dental committee. There were challenges associated with involving non-salaried dental practitioners without a source of funding, and with communicating with the wider dental community. The new Wessex LDN needs to be adequately resourced and integrated into the local commissioning structure, as well as the wider health system, to function effectively. Most importantly, the LDN needs local dental professionals to embrace the opportunities for leadership and use their skills to inform and influence local dental commissioning for the benefit of the local population.

Manx Gaelic: The Manx Gaelic Language in Education in the Isle of Man. Regional Dossiers Series

Science.gov (United States)

McArdle, Fiona, Comp.; Teare, Robert, Comp.

2016-01-01

This regional dossier aims at providing a concise description of and basic statistics on minority language education in a specific region of Europe--the Isle of Man. Aspects that are addressed include features of the education system, recent educational policies, main actors, legal arrangements, and support structures, as well as quantitative…

Characterization of herring populations west of the British Isles: an investigation of mixing based on otolith microchemistry

NARCIS (Netherlands)

Geffen, A.J.; Nash, R.D.M.; Dickey-Collas, M.

2011-01-01

Herring along the west coast of the British Isles are managed and assessed as a series of discrete stocks. The relationship between the spawning components, mixed (feeding) aggregations, and juveniles in nursery areas for these stocks was modelled by discriminant analysis and integrated stock

77 FR 35619 - Safety Zone; Old Fashion 4th July Fireworks, Presque Isle Bay, Erie, PA

Science.gov (United States)

2012-06-14

...-AA00 Safety Zone; Old Fashion 4th July Fireworks, Presque Isle Bay, Erie, PA AGENCY: Coast Guard, DHS... during the Old Fashion 4th July Fireworks display. This temporary safety zone is necessary to protect... ensure the safety of spectators and vessels during the Old Fashion 4th July Fireworks. [[Page 35620...

Spatio-temporal variability of streamwater chemistry within a Peri-urban Mediterranean catchment

Science.gov (United States)

Ferreira, Carla S. S.; Walsh, Rory P. D.; Ferreira, António J. D.; Coelho, Celeste O. A.

2015-04-01

The complex landscape of peri-urban areas, characterized by a mosaic of land-uses and urban fabric, provides different sources of runoff and pollutants which affect stream ecosystems. This study investigates the impact of land-uses and their location within catchments on streamwater quality in a peri-urban Mediterranean catchment, including temporal variations driven by antecedent weather and rainstorm characteristics. The study is based in Ribeira dos Covões, a small (6 km2) catchment in the city of Coimbra, central Portugal. Land-use is dominated by woodland (56%) and urban cover (40%), with a small agriculture area (4%). Streamwater was monitored at the catchment outlet (ESAC) and three upstream locations: Espírito Santo and Porto Bordalo, with similar urban cover (42% and 49%) but different imperviousness (27% and 15%) and lithologies (sandstone versus limestone), and Quinta with lower urban extent (25%) but including a construction site covering 10% of the area. Samples collected throughout ten rainfall events between October 2011 and March 2013 were analysed for natural water chemistry and major pollutants (notably ammonium, nitrates, total phosphorus, COD and metals). In the paper, temporal variations in water quality are explored via hysteresis loop and correlation analysis. Hydrological regime exerted a major influence on water quality. Major nutrients declined within and after the dry summer than in winter events, because of limited dilution by the low stream baseflow. Through the wet season, increasing baseflow led to increased concentrations of major cations (Na, Mg and Ca) because of reduced dilution by solute-poor stormflow. Espírito Santo, the most urbanized sub-catchment, displayed higher concentrations of COD and NO3 (tended to peak with stormflow), but the latter was thought to result from agricultural fields located adjacent the tributary. At the catchment outlet (ESAC), the high Nk and NH4 concentrations exceeded water quality standards (2 mg

Hydrochemical processes in lowland rivers: insights from in situ, high-resolution monitoring

Directory of Open Access Journals (Sweden)

A. J. Wade

2012-11-01

Full Text Available This paper introduces new insights into the hydrochemical functioning of lowland river systems using field-based spectrophotometric and electrode technologies. The streamwater concentrations of nitrogen species and phosphorus fractions were measured at hourly intervals on a continuous basis at two contrasting sites on tributaries of the River Thames – one draining a rural catchment, the River Enborne, and one draining a more urban system, The Cut. The measurements complement those from an existing network of multi-parameter water quality sondes maintained across the Thames catchment and weekly monitoring based on grab samples. The results of the sub-daily monitoring show that streamwater phosphorus concentrations display highly complex dynamics under storm conditions dependent on the antecedent catchment wetness, and that diurnal phosphorus and nitrogen cycles occur under low flow conditions. The diurnal patterns highlight the dominance of sewage inputs in controlling the streamwater phosphorus and nitrogen concentrations at low flows, even at a distance of 7 km from the nearest sewage treatment works in the rural River Enborne. The time of sample collection is important when judging water quality against ecological thresholds or standards. An exhaustion of the supply of phosphorus from diffuse and multiple septic tank sources during storm events was evident and load estimation was not improved by sub-daily monitoring beyond that achieved by daily sampling because of the eventual reduction in the phosphorus mass entering the stream during events. The results highlight the utility of sub-daily water quality measurements and the discussion considers the practicalities and challenges of in situ, sub-daily monitoring.

La revista Zanan, de la iraní Shahla Sherkat, y su contribución al feminismo islámico

Directory of Open Access Journals (Sweden)

Rocío Velasco de Castro

2012-06-01

Full Text Available En cualquier sociedad, el feminismo conforma una parte importante de la lucha por los derechos humanos. En las sociedades islámicas, además, muchas de las militantes feministas lideran los movimientos ciudadanos y sus demandas de libertad. En este proceso, la palabra como medio de expresión y de denuncia, constituye un eficaz y peligroso instrumento para informar y concienciar a la población. Al igual que otras periodistas y escritoras perseguidas, el testimonio de Sherkat y de su revista, Zanan, están considerados como uno de los principales portavoces no sólo del feminismo islámico en el país, sino también de la libertad de expresión cercenada por un régimen político dictatorial.

Long-term sodium chloride retention in a rural watershed: legacy effects of road salt on streamwater concentration.

Science.gov (United States)

Kelly, Victoria R; Lovett, Gary M; Weathers, Kathleen C; Findlay, Stuart E G; Strayer, David L; Burns, David I; Likens, Gene E

2008-01-15

Sodium and chloride concentrations and export increased from 1986 to 2005 in a rural stream in southeastern New York. Concentrations increased 1.5 mg/L per year (chloride) and 0.9 mg/L per year (sodium), and export increased 33,000 kg/year (chloride) and 20,000 kg/year (sodium) during this period. We estimate that salt used for deicing accounted for 91% of the sodium chloride input to the watershed, while sewage and water softeners accounted for less than 10% of the input. Road salt use in the watershed did not increase during the study, but sodium and chloride from sewage and water softeners is likely to have increased slightly due to a small increase in population. Increased input from sewage and water softeners cannot account for the increase in concentration and export from the watershed. Model results suggest that the increase in streamwater concentration and export was likely due to a lag effect of long-term road salt use and subsurface buildup.

Imaging a fossil oolitic system with GPR, insights into the exposures of the Isle of Portland (UK)

DEFF Research Database (Denmark)

Moreau, Julien; Hansen, Trine Lykke; Nielsen, Lars

of years. The regional exposure quality is very high with a potential 3D control. The site has seen generations of geologist trainees coming for field work. The Wessex Basin where the Isle is sitting contains an active petroleum system and the geologists visiting/training there use the carbonates...

Ground water for public water supply at Windigo, Isle Royale National Park, Michigan

Science.gov (United States)

Grannemann, N.G.; Twenter, F.R.

1982-01-01

Three test holes drilled at Windigo in Isle Royale National Park in 1981 indicate that the ophitic basaltic lava flows underlying the area contain little water and cannot be considered a source for public water supply. The holes were 135, 175, and 71 feet deep. One hole yielded about 1 gallon of water perminute; the other two yielded less. Glacial deposits seem to offer the best opportunity for developing a ground-water supply of 5 to 10 gallons per minute.

A condição das mulheres no Islã: a questão da igualdade Islamic women's status: the question of equality

Directory of Open Access Journals (Sweden)

Aïcha El Hajjami

2008-06-01

Full Text Available No ocidente, o tema da condição das mulheres no Islã está ligado à representação que geralmente se faz do Islã e dos muçulmanos. É uma representação constituída por estereótipos, esquematizações reducionistas e por confusões conceituais. A realidade do Islã e das sociedades muçulmanas possui muito mais nuances e freqüentemente não corresponde às idéias estabelecidas. A condição de inferioridade e precariedade a que está confinada a maior parte das mulheres muçulmanas, revela principalmente a hegemonia de uma mentalidade e de um sistema patriarcal que instrumentaliza sua leitura da religião para legitimar as situações de dominação, de violência e de exclusão em relação às mulheres. Partindo desta constatação, a autora propõe uma outra leitura do Islã e uma reflexão sobre a noção de igualdade no Alcorão e Sunna, na sua relação com o contexto da revelação, as finalidades da Chari'a e as perspectivas de evolução que podem revelar o referencial islâmico. Este trabalho de base é passível de reduzir as distâncias entre os princípios de igualdade entre os sexos inscritos nas convenções internacionais e seu equivalente no Islã.The Western idea relative to Islamic women's status is linked to the representations generally held on Islam and Muslim people. These representantions are riddled by esterotypes, reductionist schemas and conceptual confusions. Islam and Muslim societies' reality is much more nuanced and common held ideas do not correspond to it. The inferior status and poverty in which most of Muslim women are confined show the hegemony of a mentality and a patriarchal system that uses its readings of religion in order to legitimate the domination, violence and exclusion of women. Beginning with this idea, the author proposes another reading of Islam and a reflection about the equality notions in the Coran and in the Sunna in the context of revelation, Chari'a objectives and the

Las plantas que llegaron de Levante. Acerca del legado alimentario islámico en la Cataluña Medieval

Directory of Open Access Journals (Sweden)

Riera Melis, Antoni

2001-12-01

Full Text Available During the High Middle Ages, the Islam encouraged a deep agricultural renewal in the lands between India and Península Ibérica. The new musulman agriculture introduced in the Western Mediterranean countries some unknown vegetable products, such as sugar-cane, rice, citrics, egg-plant and spinach. Between the 10th and 13th centuries, these five products played an important role in the andalusian cookery. In the Late Middle Ages, the Catalan adopted some islamic cultural elements. High Christian cookery introduced these new products to their own style and created new recepies quite different from their islamic models.

Durante la Alta Edad Media, la expansión islámica estimuló una profunda renovación agraria en la franja de territorios comprendidos entre la India y la Península Ibérica. La nueva agricultura musulmana introdujo en el Mediterráneo Occidental especies vegetales desconocidas, como la caña de azúcar, el arroz, los cítricos, la berenjena y la espinaca. Estos cinco alimentos desempeñaron, entre los siglos X y XIII, un papel muy importante en la cocina andalusí. Los catalanes, en la Baja Edad Media, adoptaron bastantes elementos culturales islámicos. La alta cocina cristiana integró estos productos a su propio estilo, creando recetas bastante diferentes a los modelos islámicos.

Detonation Product EOS Studies: Using ISLS to Refine Cheetah

Science.gov (United States)

Zaug, J. M.; Howard, W. M.; Fried, L. E.; Hansen, D. W.

2002-07-01

Knowledge of an effective interatomic potential function underlies any effort to predict or rationalize the properties of solids and liquids. The experiments we undertake are directed towards determination of equilibrium and dynamic properties of simple fluids at densities sufficiently high that traditional computational methods and semi-empirical forms successful at ambient conditions may require reconsideration. In this paper we present high-pressure and temperature experimental sound speed data on a simple fluid, methanol. Impulsive Stimulated Light Scattering (ISLS) conducted on diamond-anvil cell (DAC) encapsulated samples offers an experimental approach to determine cross-pair potential interactions through equation of state determinations. In addition the kinetics of structural relaxation in fluids can be studied. We compare our experimental results with our thermochemical computational model Cheetah. Experimentally grounded computational models provide a good basis to confidently understand the chemical nature of reactions at extreme conditions.

Atomic Energy and Radioactive Substances. The Nuclear Installations (Isle of Man) Order 1977

International Nuclear Information System (INIS)

1977-01-01

This Order extends to the Isle of Man, with the exceptions, adaptations and modifications specified in the Schedule, those provisions of the Nuclear Installations Act 1965, as amended, which relate to the duty in respect of the carriage of nuclear matter, to the right to compensation for breach of that duty and to the bringing and satisfaction of claims. Under the Nuclear Installations Act, the duty of the operator is to secure that no nuclear occurrence taking place within the realm of the Act causes injury to persons or damage to property. (NEA) [fr

Summary of : piloting a local dental network across Hampshire and Isle of Wight Primary Care Trusts.

Science.gov (United States)

McGrady, Dr Michael

2014-09-01

To pilot a local dental network (LDN) within the Hampshire and Isle of Wight region. An LDN Coordinating Group was set up, which was chaired by the local consultant in dental public health and included representatives from dental commissioning and performance management teams, dental practice advisory team, finance, Oxford and Wessex Dental Deanery and the Hampshire and Isle of Wight Local Dental Committee. The LDN successfully led the organisation of a leadership training course for local dentists, and produced recommendations for local oral surgery and orthodontics care pathways. Key to the success was the collaboration achieved between the commissioners, local postgraduate dental deanery and local dental committee. There were challenges associated with involving non-salaried dental practitioners without a source of funding, and with communicating with the wider dental community. The new Wessex LDN needs to be adequately resourced and integrated into the local commissioning structure, as well as the wider health system, to function effectively. Most importantly, the LDN needs local dental professionals to embrace the opportunities for leadership and use their skills to inform and influence local dental commissioning for the benefit of the local population.

Temporal genetic variation of the red fox, Vulpes vulpes, across western Europe and the British Isles

Science.gov (United States)

Edwards, Ceiridwen J.; Soulsbury, Carl D.; Statham, Mark J.; Ho, Simon Y. W.; Wall, Dave; Dolf, Gaudenz; Iossa, Graziella; Baker, Phillip J.; Harris, Stephen; Sacks, Benjamin N.; Bradley, Daniel G.

2012-12-01

Quaternary climatic fluctuations have had profound effects on the phylogeographic structure of many species. Classically, species were thought to have become isolated in peninsular refugia, but there is limited evidence that large, non-polar species survived outside traditional refugial areas. We examined the phylogeographic structure of the red fox (Vulpes vulpes), a species that shows high ecological adaptability in the western Palaearctic region. We compared mitochondrial DNA sequences (cytochrome b and control region) from 399 modern and 31 ancient individuals from across Europe. Our objective was to test whether red foxes colonised the British Isles from mainland Europe in the late Pleistocene, or whether there is evidence that they persisted in the region through the Last Glacial Maximum. We found red foxes to show a high degree of phylogeographic structuring across Europe and, consistent with palaeontological and ancient DNA evidence, confirmed via phylogenetic indicators that red foxes were persistent in areas outside peninsular refugia during the last ice age. Bayesian analyses and tests of neutrality indicated population expansion. We conclude that there is evidence that red foxes from the British Isles derived from central European populations that became isolated after the closure of the landbridge with Europe.

Improving niche projections of plant species under climate change: Silene acaulis on the British Isles as a case study

Science.gov (United States)

Ferrarini, Alessandro; Alsafran, Mohammed H. S. A.; Dai, Junhu; Alatalo, Juha M.

2018-04-01

Empirical works to assist in choosing climatically relevant variables in the attempt to predict climate change impacts on plant species are limited. Further uncertainties arise in choice of an appropriate niche model. In this study we devised and tested a sharp methodological framework, based on stringent variable ranking and filtering and flexible model selection, to minimize uncertainty in both niche modelling and successive projection of plant species distributions. We used our approach to develop an accurate, parsimonious model of Silene acaulis (L.) presence/absence on the British Isles and to project its presence/absence under climate change. The approach suggests the importance of (a) defining a reduced set of climate variables, actually relevant to species presence/absence, from an extensive list of climate predictors, and (b) considering climate extremes instead of, or together with, climate averages in projections of plant species presence/absence under future climate scenarios. Our methodological approach reduced the number of relevant climate predictors by 95.23% (from 84 to only 4), while simultaneously achieving high cross-validated accuracy (97.84%) confirming enhanced model performance. Projections produced under different climate scenarios suggest that S. acaulis will likely face climate-driven fast decline in suitable areas on the British Isles, and that upward and northward shifts to occupy new climatically suitable areas are improbable in the future. Our results also imply that conservation measures for S. acaulis based upon assisted colonization are unlikely to succeed on the British Isles due to the absence of climatically suitable habitat, so different conservation actions (seed banks and/or botanical gardens) are needed.

Creation and (Re)presentation of Historical Discourse in Isle of Passion by Laura Restrepo

OpenAIRE

Daniela Melis

2011-01-01

Published in Colombia in 1989, but neglected until the author’s later distinction, Laura Restrepo’s first novel, Isle of Passion , focuses on historical facts, as well as on the issues that arise when the impact of events is articulated in official discourse. This study—drawing from Walter Mignolo’s idea of decolonial theory—explores how Restrepo’s attempt to rewrite history following “an-other logic, an-other language, an-other thinking” contributes to the decolonization of knowledge, being...

ISL1 protein transduction promotes cardiomyocyte differentiation from human embryonic stem cells.

Directory of Open Access Journals (Sweden)

Hananeh Fonoudi

Full Text Available BACKGROUND: Human embryonic stem cells (hESCs have the potential to provide an unlimited source of cardiomyocytes, which are invaluable resources for drug or toxicology screening, medical research, and cell therapy. Currently a number of obstacles exist such as the insufficient efficiency of differentiation protocols, which should be overcome before hESC-derived cardiomyocytes can be used for clinical applications. Although the differentiation efficiency can be improved by the genetic manipulation of hESCs to over-express cardiac-specific transcription factors, these differentiated cells are not safe enough to be applied in cell therapy. Protein transduction has been demonstrated as an alternative approach for increasing the efficiency of hESCs differentiation toward cardiomyocytes. METHODS: We present an efficient protocol for the differentiation of hESCs in suspension by direct introduction of a LIM homeodomain transcription factor, Islet1 (ISL1 recombinant protein into the cells. RESULTS: We found that the highest beating clusters were derived by continuous treatment of hESCs with 40 µg/ml recombinant ISL1 protein during days 1-8 after the initiation of differentiation. The treatment resulted in up to a 3-fold increase in the number of beating areas. In addition, the number of cells that expressed cardiac specific markers (cTnT, CONNEXIN 43, ACTININ, and GATA4 doubled. This protocol was also reproducible for another hESC line. CONCLUSIONS: This study has presented a new, efficient, and reproducible procedure for cardiomyocytes differentiation. Our results will pave the way for scaled up and controlled differentiation of hESCs to be used for biomedical applications in a bioreactor culture system.

Soil properties associated with net nitrification following watershed conversion with Appalachian hardwoods to Norway spruce

Science.gov (United States)

Charlene N. Kelly; Stephen H. Schoenholtz; Mary Beth Adams

2011-01-01

Nitrate (NO3-N) in soil solution and streamwater can be an important vector of nitrogen (N) loss from forested watersheds, and nitrification is associated with negative consequences of soil acidification and eutrophication of aquatic ecosystems. The purpose of this study was to identify vegetation-mediated soil properties that may control...

Inshore craft traditional working vessels of the british isles

CERN Document Server

Greenhill, Basil

2013-01-01

This comprehensive reference work describes and illustrates some 200 types of inshore craft that once fished and traded, under oar and sail, around the coasts of the British Isles. The types are arranged by coastal area and each is described in terms of its shape and design, fitness for location and purpose, build, evolution and geographical distribution. Details of dimensions, rig, building materials, seamanship and the survival of examples are given where known, while hundreds of line drawings and photographs show the vessels in their original forms.A team of twelve experts describe all these boat types and, in addition, there are introductions to the main geographic areas outlining the physical environments, fisheries and other uses of the sea that have influenced boat design; maps of all the areas show ports and physical features.At the beginning of the last century sail and oar dominated fisheries and local trade: one hundred years later those craft have all but vanished. This book brings alive for marit...

Matrimonio poligámico, inmigración islámica y libertad de conciencia en España

Directory of Open Access Journals (Sweden)

Margarita Lema Tomé

2003-01-01

Full Text Available En este artículo se analiza el derecho a contraer nupcias en situaciones de inmigración, mostrando las diferencias ideológicas que pueden ocurrir en los Estados de origen y destino en la forma de concebir el matrimonio. El artículo se centra en la experiencia de los inmigrantes islámicos en España. Un tema especialmente difícil es el matrimonio poligámico, institución arraigada en los países islámicos que ha planteado varios problemas, especialmente desde la perspectiva jurídica. La solución a la que se ha llegado en España procede de la vía jurisprudencial y tiene como punto de referencia dos casos: el de Diop, un inmigrante senegalés que fallece dejando dos viudas, y el de un trabajador marroquí, que había estado casado con dos mujeres a la vez durante un periodo, quien muere tras haberse divorciado de una de ellas

Decline of heterozygosity in a large but isolated population: a 45-year examination of moose genetic diversity on Isle Royale

Directory of Open Access Journals (Sweden)

Renae L. Sattler

2017-07-01

Full Text Available Wildlife conservation and management approaches typically focus on demographic measurements to assess population viability over both short and long periods. However, genetic diversity is an important predictor of long term population vitality. We investigated the pattern of change in genetic diversity in a large and likely isolated moose (Alces alces population on Isle Royale (Lake Superior from 1960–2005. We characterized samples, partitioned into five different 5-year periods, using nine microsatellite loci and a portion of the mtDNA control region. We also simulated the moose population to generate a theoretical backdrop of genetic diversity change. In the empirical data, we found that the number of alleles was consistently low and that observed heterozygosity notably declined from 1960 to 2005 (p = 0.08, R2 = 0.70. Furthermore, inbreeding coefficients approximately doubled from 0.08 in 1960–65 to 0.16 in 2000–05. Finally, we found that the empirical rate of observed heterozygosity decline was faster than the rate of observed heterozygosity loss in our simulations. Combined, these data suggest that genetic drift and inbreeding occurred in the Isle Royale moose populations over the study period, leading to significant losses in heterozygosity. Although inbreeding can be mitigated by migration, we found no evidence to support the occurrence of recent migrants into the population using analysis of our mtDNA haplotypes nor microsatellite data. Therefore, the Isle Royale moose population illustrates that even large populations are subjected to inbreeding in the absence of migration.

Simulating the long-term chemistry of an upland UK catchment: Major solutes and acidification

Energy Technology Data Exchange (ETDEWEB)

Tipping, E. [Centre for Ecology and Hydrology (Lancaster), Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom)]. E-mail: et@ceh.ac.uk; Lawlor, A.J. [Centre for Ecology and Hydrology (Lancaster), Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom); Lofts, S. [Centre for Ecology and Hydrology (Lancaster), Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom)

2006-05-15

CHUM-AM was used to investigate changes in soil and water chemical variables in four moorland sub-catchments in Cumbria UK, to which non-marine S deposition has declined by 65% since the 1970s. The principal processes represented in the model comprise N and S uptake and release, water movements, the binding of cations by soil organic matter, chemical interactions in solution, and chemical weathering. CHUM-AM reproduced reasonably well the current soil pH and pools of N and S, and changes in streamwater chemistry over the period 1970-2000, notably decreases in the concentrations of alkaline earth cations and sulphate, and increases in pH. The model also predicts streamwater pH-Al relationships in agreement with observations. Predictive calculations suggest that constant atmospheric deposition of N at present rates will lead to N saturation and re-acidification, whereas a 50% reduction in N would stabilise soil and streamwater pH at about the present levels. - CHUM-AM accounts for recovery from acidification due to sulphur deposition, but predicts re-acidification if nitrogen deposition is not reduced.

The Straz block ISL project - Case history

International Nuclear Information System (INIS)

Benes, V.; Slezak, J.

1997-01-01

The ISL project on the Straz deposit, located about 90 km north of Prague, the capital of the Czech Republic, is the only commercial in situe leaching plant, that has been operated in the Czech Republic. The facility began its first industrial production at the end of 1969, some 5 years after the discovery of the sandstone-hosted uranium deposits in the northern part of the Bohemian Cretaceous basin. The orebodies lie 180 to 280 m below the surface, depending on its configuration. The orebodies are situated in the lower part of the Cenomanian sediments - in brackish sediments, and especially in marine sandstones. At present, the leaching fields have the area of about 650 ha (6.5 km 2 ). Some of these fields were closed, wells decommissioned and surface is being reclaimed. Because of the technological properties of uranium ores and host rocks, the leaching is very slow. Therefore some leaching fields have been in production for more than 25 years and they still produce industrial amounts of uranium. The plants were constructed for the capacity of 30 to 40 m 3 /minute (400 to 650 litres per second). The highest annual production was more than 800 tonnes. The total amount of produced uranium was 15,000 tonnes between 1968 and 1994. (author)

'ISL pattern reserve requirements for today's spot price,' or 'how many in-place pounds are needed for a mining pattern to be profitable in today's market'

International Nuclear Information System (INIS)

Anthony, H.L.

2000-01-01

Recent uranium spot market values place additional burdens on the geologist and project manager to identify mineralized ore that will yield a profitable return on investment to the mining venture and its investors. The author reviews the various cost components that comprise the total work effort required to produce uranium via ISL methods to arrive at a suitable ore grade that will guarantee profitably. Amortization of costs based on recent expenditures for typical ISL operations are used in conjunction with wellfield development, operating and restoration costs to determine the ore value required to show a positive return on investment. (author)

O Papa, o Islã e o politicamente correto The Pope, Islam and political correctedness

Directory of Open Access Journals (Sweden)

José Augusto Lindgren Alves

2007-01-01

Full Text Available Ao fazer citação considerada ofensiva ao Islã em conferência que proferiu na Alemanha em 2006, o Papa Bento XVI não visava somente aos muçulmanos, mas, também, aos ocidentais cristãos e ateus. Seu objetivo não era ofender o Islã gratuitamente, mas forçar os islamitas e ocidentais que abandonaram o racionalismo a assimilarem, num caso, e a reassimilarem, no outro, a razão universalista como elemento essencial ao próprio diálogo entre as religiões. A fala do Papa tem tido repercussões que transcendem o âmbito religioso, atingindo noções e práticas multiculturalistas que pareciam intocáveis.When making a quotation that was considered offensive to Islam, in 2006, in a conference in Germany, Pope Benedict XVI targeted not only the Muslims, but also Christian and Atheist Westerners. His aim was not to offend Islam without a motive, but to force both the Muslims and Westerners that had forsaken rationalism to reach back to Reason as an essential element for the very dialogue between the two religions. The Pope’s speech has had repercussion far beyond the religious sphere, attaining notions and practices of multiculturalism that seemed untouchable.

Modelling Future Coronary Heart Disease Mortality to 2030 in the British Isles.

Directory of Open Access Journals (Sweden)

John Hughes

Full Text Available Despite rapid declines over the last two decades, coronary heart disease (CHD mortality rates in the British Isles are still amongst the highest in Europe. This study uses a modelling approach to compare the potential impact of future risk factor scenarios relating to smoking and physical activity levels, dietary salt and saturated fat intakes on future CHD mortality in three countries: Northern Ireland (NI, Republic of Ireland (RoI and Scotland.CHD mortality models previously developed and validated in each country were extended to predict potential reductions in CHD mortality from 2010 (baseline year to 2030. Risk factor trends data from recent surveys at baseline were used to model alternative future risk factor scenarios: Absolute decreases in (i smoking prevalence and (ii physical inactivity rates of up to 15% by 2030; relative decreases in (iii dietary salt intake of up to 30% by 2030 and (iv dietary saturated fat of up to 6% by 2030. Probabilistic sensitivity analyses were then conducted.Projected populations in 2030 were 1.3, 3.4 and 3.9 million in NI, RoI and Scotland respectively (adults aged 25-84. In 2030: assuming recent declining mortality trends continue: 15% absolute reductions in smoking could decrease CHD deaths by 5.8-7.2%. 15% absolute reductions in physical inactivity levels could decrease CHD deaths by 3.1-3.6%. Relative reductions in salt intake of 30% could decrease CHD deaths by 5.2-5.6% and a 6% reduction in saturated fat intake might decrease CHD deaths by some 7.8-9.0%. These projections remained stable under a wide range of sensitivity analyses.Feasible reductions in four cardiovascular risk factors (already achieved elsewhere could substantially reduce future coronary deaths. More aggressive polices are therefore needed in the British Isles to control tobacco, promote healthy food and increase physical activity.

33 CFR 334.40 - Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target...

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Atlantic Ocean in vicinity of Duck Island, Maine, Isles of Shoals; naval aircraft bombing target area. 334.40 Section 334.40... Shoals; naval aircraft bombing target area. (a) The danger zone. A circular area with a radius of 500...

Parasitic nematodes of the genus Syphacia Seurat, 1916 infecting Muridae in the British Isles, and the peculiar case of Syphacia frederici.

NARCIS (Netherlands)

Stewart, Alex; Lowe, Ann; Smales, Lesley; Bajer, Anna; Bradley, Jan; Dwużnik, Dorota; Franssen, Frits; Griffith, Jack; Stuart, Peter; Turner, Cyan; Zaleśny, Grzegorz; Behnke, Jerzy M

2017-01-01

Syphacia stroma (von Linstow, 1884) Morgan, 1932 and Syphacia frederici Roman, 1945 are oxyurid nematodes that parasitize two murid rodents, Apodemus sylvaticus and Apodemus flavicollis, on the European mainland. Only S. stroma has been recorded previously in Apodemus spp. from the British Isles.

Studies of environmental radioactivity in Cumbria. Part 4 Caesium-137 and plutonium in soils of Cumbria and the Isle of Man

International Nuclear Information System (INIS)

Cawse, P.A.

1980-08-01

A network of soil sampling sites covering an area of some 2500 km 2 in Cumbria and the whole of the Isle of Man was selected and sampled in 1978. Soils from permanent grassland, coniferous woodland and deciduous woodland were examined, to a depth of 30 cm. The spatial distribution of sampling points is based on a grid of 10 km side. The objective of the study is to provide information on the integrated deposition of Cs-137, Pu-239+240 and Pu-238 from the atmosphere, and to determine the distribution of possible emissions from the nuclear establishment at Windscale in the presence of radioactivity deposited from nuclear weapons fallout, that is superimposed upon the natural background of radioactivity in soil. Results from soil samples collected in 1978 in Cumbria and the Isle of Man are compared with the average integrated deposition for UK soils from nuclear fallout. In the Isle of Man no radioactivity is observed in excess of nuclear weapons fallout, but in Cumbria excess levels of plutonium are detected in coastal lowland areas under permanent grassland probably due to the transport of radioactive material from sea to land. At three sampling sites on grassland and woodland within 2.3 km of the Windscale stacks, the excess plutonium and Cs-137 in soil could be attributed mainly to atmospheric discharges from Windscale. The observed deposition of radioactivity has little radiological significance, based on assessment of risk by inhalation of soil dust that contains plutonium. (author)

Assessing the conservation status of marine habitats: thoughts from a sandflat on the Isles of Scilly.

OpenAIRE

Warwick, RM; Somerfield, PJ

2015-01-01

Abstract Statutory monitoring of the fauna of the ‘mudflats and sandflats not covered by seawater at low tide’ biotope complex on St Martin's Flats, a part of the Isles of Scilly Complex Special Area of Conservation, was undertaken in 2000, 2004 and 2009. The targets set by Natural England for “characteristic biotopes” were that “composite species, abundance and diversity should not deviate significantly from an established baseline, subject to natural change”. The three specified biotope...

La bioética jurídica islámica como fenómeno jurídico-cultural regional: Tensiones internas y externas en la actualidad producidas en su inserción como derechos humanos

Directory of Open Access Journals (Sweden)

Mikunda Franco, Emilio

2010-10-01

Full Text Available This paper is the third Part of a Trilogy around the socalled Islamic World. It presents us the “Islamic bioethics” as a legal regional phenomenon instead of an international one, as believed in the West World. It contains a glossary sui generis with specifically Islamic connotations. It means, with similarities and differences far away from the usefully ones in the West World and Spain, so that a big amount of mistakes of interpretation can be avoided, because the aimed words are written in similar way but with very different signification. The paper analyzes the tensions produced in and outside of the Islamic World by associating bioethics and human rights. Such a situation reproduces –in the meaning of the author– another old problem up-to-day not resolved, the so-called “Universal human rights versus regional Islamic human rights”. A selected bibliography in the end contains specifically themes of human rights, Islamic bioethics and constitutionalism, and finally the own contributions of the author.

El presente trabajo corona la tercera parte de una trilogía en torno al Mundo islámico, tratando la “bioética jurídica islámica” como fenómeno jurídico regional frente a la occidental, autodenominada universal. (Anteriores partes fueron “Derechos humanos”, y “constitucionalismo” islámicos. Aporta un glosario terminológico islámico sui generis con connotaciones específicas, similitudes y diferencias frente a la occidental al uso en España, en evitación de posibles confusiones o lapsos debidos al uso de términos de idéntico significante y homólogo significado. Analiza tensiones de todo tipo producidas al asociar “bioética y derechos humanos en el mundo islámico”. Condensa en diez tesis finales la polémica y problemática resultante, que reproduce –según su autor– análoga situación de otrora entre “Derechos humanos universales versus Derechos humanos islámicos regionales”. La

O monoteísmo islâmico

Directory of Open Access Journals (Sweden)

Antonio Ozaí da Silva

2010-12-01

Full Text Available A proposta deste artigo é analisar a as origens e fundamentos da fé monoteísta islâmica, sua singularidade e o significado do Profeta Maomé enquanto modelo religioso, moral e político para a conduta dos muçulmanos. O objetivo é contribuir para a reflexão crítica sobre o Islamismo, para além dos preconceitos lingüísticos, políticos e culturais alimentados por setores da mídia ocidental, a qual tende a restringir o islamismo à vertente fundamentalista. As religiões monoteístas têm os seus fundamentalismos e suas “guerras justas”. E, no que diz respeito ao monoteísmo, as religiões não diferem em sua essência, já que se fundamentam na crença no Deus Único. Objetiva-se, ainda, instigar a análise sobre as relações entre religião e política, um tema polêmico em todas as crenças monoteístas.

Stream Nitrogen Inputs Reflect Groundwater Across a Snowmelt-Dominated Montane to Urban Watershed.

Science.gov (United States)

Hall, Steven J; Weintraub, Samantha R; Eiriksson, David; Brooks, Paul D; Baker, Michelle A; Bowen, Gabriel J; Bowling, David R

2016-02-02

Snowmelt dominates the hydrograph of many temperate montane streams, yet little work has characterized how streamwater sources and nitrogen (N) dynamics vary across wildland to urban land use gradients in these watersheds. Across a third-order catchment in Salt Lake City, Utah, we asked where and when groundwater vs shallow surface water inputs controlled stream discharge and N dynamics. Stream water isotopes (δ(2)H and δ(18)O) reflected a consistent snowmelt water source during baseflow. Near-chemostatic relationships between conservative ions and discharge implied that groundwater dominated discharge year-round across the montane and urban sites, challenging the conceptual emphasis on direct stormwater inputs to urban streams. Stream and groundwater NO3(-) concentrations remained consistently low during snowmelt and baseflow in most montane and urban stream reaches, indicating effective subsurface N retention or denitrification and minimal impact of fertilizer or deposition N sources. Rather, NO3(-) concentrations increased 50-fold following urban groundwater inputs, showing that subsurface flow paths potentially impact nutrient loading more than surficial land use. Isotopic composition of H2O and NO3(-) suggested that snowmelt-derived urban groundwater intercepted NO3(-) from leaking sewers. Sewer maintenance could potentially mitigate hotspots of stream N inputs at mountain/valley transitions, which have been largely overlooked in semiarid urban ecosystems.

Testing seasonal and long-term controls of streamwater DOC using empirical and process-based models.

Science.gov (United States)

Futter, Martyn N; de Wit, Heleen A

2008-12-15

Concentrations of dissolved organic carbon (DOC) in surface waters are increasing across Europe and parts of North America. Several mechanisms have been proposed to explain these increases including reductions in acid deposition, change in frequency of winter storms and changes in temperature and precipitation patterns. We used two modelling approaches to identify the mechanisms responsible for changing surface water DOC concentrations. Empirical regression analysis and INCA-C, a process-based model of stream-water DOC, were used to simulate long-term (1986--2003) patterns in stream water DOC concentrations in a small boreal stream. Both modelling approaches successfully simulated seasonal and inter-annual patterns in DOC concentration. In both models, seasonal patterns of DOC concentration were controlled by hydrology and inter-annual patterns were explained by climatic variation. There was a non-linear relationship between warmer summer temperatures and INCA-C predicted DOC. Only the empirical model was able to satisfactorily simulate the observed long-term increase in DOC. The observed long-term trends in DOC are likely to be driven by in-soil processes controlled by SO4(2-) and Cl(-) deposition, and to a lesser extent by temperature-controlled processes. Given the projected changes in climate and deposition, future modelling and experimental research should focus on the possible effects of soil temperature and moisture on organic carbon production, sorption and desorption rates, and chemical controls on organic matter solubility.

77 FR 4897 - Safety Zone; M/V Del Monte Live-Fire Gun Exercise, James River, Isle of Wight, VA

Science.gov (United States)

2012-02-01

...-AA00 Safety Zone; M/V Del Monte Live-Fire Gun Exercise, James River, Isle of Wight, VA AGENCY: Coast... provide for the safety of life on navigable waters during the live-fire gun exercises on the M/V Del Monte... associated with the live-fire gun exercise. DATES: This rule is effective in the CFR on February 1, 2012...

76 FR 31848 - Safety Zone; M/V Del Monte Live-Fire Gun Exercise, James River, Isle of Wight, Virginia

Science.gov (United States)

2011-06-02

...-AA00 Safety Zone; M/V Del Monte Live-Fire Gun Exercise, James River, Isle of Wight, Virginia AGENCY... provide for the safety of life on navigable waters during the live-fire gun exercises on the M/V Del Monte... associated with the live-fire gun exercise. DATES: This rule will be effective from 11 a.m. June 6, 2011...

Deposition and cycling of sulfur controls mercury accumulation in Isle Royale fish

Energy Technology Data Exchange (ETDEWEB)

Paul E. Drevnick; Donald E. Canfield; Patrick R. Gorski (and others) [Miami University, Oxford, OH (United States). Department of Zoology

2007-11-01

Mercury contamination of fish is a global problem. Consumption of contaminated fish is the primary route of methylmercury exposure in humans and is detrimental to health. Newly mandated reductions in anthropogenic mercury emissions aim to reduce atmospheric mercury deposition and thus mercury concentrations in fish. However, factors other than mercury deposition are important for mercury bioaccumulation in fish. In the lakes of Isle Royale, U.S.A., reduced rates of sulfate deposition since the Clean Air Act of 1970 have caused mercury concentrations in fish to decline to levels that are safe for human consumption, even without a discernible decrease in mercury deposition. Therefore, reductions in anthropogenic sulfur emissions may provide a synergistic solution to the mercury problem in sulfate-limited freshwaters. 71 refs., 3 figs., 1 tab.

O viés ideológico das traduções de livros no Brasil: o caso do terrorismo e do fundamentalismo islâmico

Directory of Open Access Journals (Sweden)

Jacques A. Wainberg

2009-09-01

Full Text Available Resumo O estudo avalia empiricamente o viés ideológico das traduções de livros para o português e editados no Brasil que tratam de temas relacionados ao terrorismo islâmico e correlatos. O levantamento do acervo de oito bibliotecas universitárias e quatro livrarias comerciais mostrou que, de setembro de 2001 a junho de 2008, foram publicadas 95 obras sobre o tema. O viés ideológico ocidentalista superou o seu concorrente, o viés orientalista. Mas a maioria das obras traduzidas e publicadas em português por editoras brasileiras apresentou um viés balanceado. Palavras-chave: Tradução; livros; ocidentalismo; orientalismo; fundamentalismo islâmico. Resumen El estudio evalúa empíricamente la tendencia ideológica de las traducciones de libros al portugués y editados en Brasil que tratan de la temática relacionada con el terrorismo islámico y con temas correlativos. El levantamiento del acervo de ocho bibliotecas universitarias y cuatro librerías comerciales mostró que, de septiembre de 2001 a junio de 2008, fueron publicadas 95 obras sobre este tema. La tendencia ideológica occidentalista superó su concurrente, la tendencia orientalista. Pero la mayoría de las obras traducidas y publicadas en portugués por editoras brasileñas presentó una tendencia balanceada. Palabras-clave: Traducción; libros; occidentalismo; orientalismo; fundamentalismo islámico. Abstract The subject of this study is the ideological bias of book translation into Portuguese on themes such as Islamic fundamentalism and terrorism. According to data collected in eight academic libraries and four bookstores, 95 books on these topics were published in Brazil. Written by foreign authors, these books were translated between September 2001 and June 2008. We observed stronger Eastern bias than Western one, but most of these books were included in the “Balanced” category. Keywords: Translation; books; Westernism; Easternism; Islamic fundamentalism.

The Lord's prerogative and an act of trust: portable antiquities in the Isle of Man

Directory of Open Access Journals (Sweden)

Allison Fox

2013-03-01

Full Text Available The Isle of Man is a self-governing British Crown dependency. As such, legislation for many areas of life differs from the neighbouring jurisdictions, including that which governs portable antiquities. The Island has a rich and varied heritage, with physical evidence from the Mesolithic to the Iron Age, through the early Christian period to Vikings and beyond. Both the Manx Treasure Trove legislation and the Act under which Manx National Heritage operates are currently under parliamentary review. These are intriguing times for Manx portable antiquities and this article seeks to explain why change is due and what options are possible.

Water-resources reconnaissance of Isle de la Gonave, Haiti

Science.gov (United States)

Troester, J.W.; Turvey, M.D.

2004-01-01

Isle de la Gonave is a 750-km2 island off the coast of Haiti. The depth to the water table ranges from less than 30 m in the Eocene and Upper Miocene limestones to over 60 m in the 300-m-thick Quaternary limestone. Annual precipitation ranges from 800-1,400 mm. Most precipitation is lost through evapotranspiration and there is virtually no surface water. Roughly estimated from chloride mass balance, about 4% of the precipitation recharges the karst aquifer. Cave pools and springs are a common source for water. Hand-dug wells provide water in coastal areas. Few productive wells have been drilled deeper than 60 m. Reconnaissance field analyses indicate that groundwater in the interior is a calcium-bicarbonate type, whereas water at the coast is a sodium-chloride type that exceeds World Health Organization recommended values for sodium and chloride. Tests for the presence of hydrogen sulfide-producing bacteria were negative in most drilled wells, but positive in cave pools, hand-dug wells, and most springs, indicating bacterial contamination of most water sources. Because of the difficulties in obtaining freshwater, the 110,000 inhabitants use an average of only 7 L per person per day.

Pararchive and Island Stories: collaborative co-design and community digital heritage on the Isle of Bute

Directory of Open Access Journals (Sweden)

Paul R.J. Duffy

2017-12-01

Full Text Available This article draws on work undertaken during two recent research projects that focused on the practices and experiences of a group of heritage volunteers working on rural settlement archaeology on the Isle of Bute, Scotland. In it we outline the process of co-creation of the YARN digital storytelling platform, explore the methodological approach employed for successful co-design, and reflect on how our initial experiences have led to a longer term, hyperlocal focus around issues of empowerment, upskilling and digital engagement in a Scottish island community.

Water chemistry and its effects on the physiology and survival of Atlantic salmon Salmo salar smolts

Science.gov (United States)

Liebich, T.; McCormick, S.D.; Kircheis, D.; Johnson, K.; Regal, R.; Hrabik, T.

2011-01-01

The physiological effects of episodic pH fluctuations on Atlantic salmon Salmo salar smolts in eastern Maine, U.S.A., were investigated. During this study, S. salar smolts were exposed to ambient stream-water chemistry conditions at nine sites in four catchments for 3 and 6 day intervals during the spring S. salar smolt migration period. Plasma chloride, plasma glucose, gill aluminium and gill Na+- and K+-ATPase levels in S. salar smolts were assessed in relation to ambient stream-water chemistry during this migration period. Changes in both plasma chloride and plasma glucose levels of S. salar smolts were strongly correlated with stream pH, and S. salar smolt mortality occurred in one study site with ambient stream pH between 5??6 and 5??8 during the study period. The findings from this study suggest that physiological effects on S. salar smolts are strongly correlated with stream pH and that in rivers and streams with low dissolved organic carbon (DOC) concentrations the threshold for physiological effects and mortality probably occurs at a higher pH and shorter exposure period than in rivers with higher DOC. Additionally, whenever an acidification event in which pH drops below 5??9 coincides with S. salar smolt migration in eastern Maine rivers, there is potential for a significant reduction in plasma ions of S. salar smolts. ?? 2011 The Fisheries Society of the British Isles.

Labirintos de Luxbûna : Alfama e a influência da arquitectura islâmica

OpenAIRE

Marreiros, Alexandre Leong Pedrosa dos Santos, 1984-

2017-01-01

Dissertação de mestrado integrado em Arquitectura, Universidade Lusíada de Lisboa, 2012 Exame público realizado em 19 de Junho de 2013 A presente dissertação propõe a leitura de um lugar, o estudo e análise, de um bairro tradicional da cidade de Lisboa – Alfama –, e a sua íntima relação com o modelo urbano e arquitectura da medina islâmica do Norte de África. A abordagem deste trabalho é desenvolvida a partir da origem do desenho da planta de Lisboa, assim como, das características g...

Element budgets of two contrasting catchments in the Black Forest (Federal Republic of Germany)

Science.gov (United States)

Feger, K. H.; Brahmer, G.; Zöttl, H. W.

1990-08-01

Rainfall and throughfall inputs of all major cations and anions, via open-field bulk precipitation and canopy throughfall, are compared with streamwater outputs in two forested catchments at higher altitudes of the Black Forest. The sites differ considerably in terms of bedrock geology, soil type, soilwater characteristics, topography, and forest management history. Deposition at both sites is almost equal and, in contrast to other forest areas in Central Europe, of a low-to-moderate level. Dry deposition does not seem to play an important role. Distinct differences in the elemental output emerge owing to the differing site conditions. At Villingen, deposited nitrogen is almost totally retained, whereas at Schluchsee, nitrogen output and input are of the same order of magnitude. This is consistent with the different nitrogen nutrition level of the stands, microbial turnover in the soil, and former management practices (change of tree species, excessive nutrient export). Sulphur is not retained in either of the catchments. At Schluchsee, sulphur export exceeds input from canopy throughfall by a factor of 2.5. The higher output rates, both of nitrogen and sulphur at Schluchsee, are due to the much higher microbial mineralization of organic matter as shown by previous incubation tests. Differences in cation and proton export are mainly caused by a different drainage pattern. In contrast to the Schluchsee catchment, where vertical water pathways prevail, the streamwater solute output at Villingen is dominated by a shallow subsurface runoff. Atmospheric deposition is a contributing, but not the dominant, factor in the biogeochemical cycling at these sites. Hence, a generally applicable quantitative definition of 'critical loads', especially for nitrogen, is illusory and the use of such numbers will be misleading.

Narrativa audiovisual, ontología y terrorismo: paradojas comunicativas en los videos del Estado Islámico

Directory of Open Access Journals (Sweden)

Aarón Rodríguez-Serrano

2017-01-01

Full Text Available El presente artículo analiza los procesos de significación e impacto global del material audiovisual generado por el autoproclamado Estado Islámico. Se trata, sin duda, de un objeto de estudio contemporáneo y de primer or-den, en cuanto gran parte de la crisis geopolítica en Oriente Próximo, así como los flujos migratorios hacia Europa, penden en este momento de las acciones bélicas de las fuerzas terroristas que emergieron de las llamadas primaveras árabes. Nuestra hipótesis de partida es que la técnica comunica-tiva de Estado Islámico no solo es una evolución salvaje de los propios pro-cesos comunicativos en las sociedades posmodernas, sino que, además, es profundamente paradójico e inconsistente en lo que a sus procesos de sig-nificación se refieren. Para analizar este material, se utilizará una metodolo-gía híbrida compuesta, en primer lugar, por una ontología política, en la que se rastrean las relaciones entre espectáculo, atrocidad, terrorismo y control político, incluyendo referencias a la existencia de la ley obscena como fundamento ideológico generador de mensajes. En segundo lugar, se repasarán someramente algunos de los recursos narrativos audiovisuales que generan significación en dichas piezas.

Luis A. García Moreno et María Jesús Viguera Molins (éd.), Del Nilo al Ebro, t. I : Estudios sobre las fuentes de la conquista islámica

OpenAIRE

Nef, Annliese

2012-01-01

Cet ouvrage est le premier volume d’un projet quadriennal en cours financé par la Communauté Autonome de Madrid et intitulé « La expansión del Imperio árabe-islámico en el Norte de África y Occidente (siglos vii-viii) según las fuentes no islámicas ». Ce projet collectif prévoyait trois étapes comme le rappelle l’introduction : d’abord, la récolte et l’analyse de sources littéraires manuscrites non islamiques (entendre non musulmanes, nous y reviendrons) sur les conquêtes arabo-musulmanes dep...

One Year of Monthly N and O Isotope Measurements in Nitrate from 18 Streamwater Monitoring Stations Within the Predominantly Pastoral Upper Manawatu Catchment, New Zealand

Science.gov (United States)

Baisden, W. T.; Douence, C.

2010-12-01

New Zealand's intensive pastoral agricultural systems have a significant impact on water quality due to nitrogen loading in rivers. A research programme has been designed to develop indicators of the sources and denitrification losses of nitrate in streamwater. This work describes the results of one year of monthly measurements at ~18 monitoring locations in the 1260 square km upper Manawatu River catchment. The catchment was chosen for study because it is among the most pastoral catchments in New Zealand, with little non-pastoral agriculture and limited forest area outside of the Tararua mountain range on the west side of the catchment. The use of N and O isotope ratios in nitrate has considerable potential to elucidate the sources and fate of nitrate with greater precision than in most other nations due to the lack of nitrate in atmospheric deposition and the lack of nitrates used as fertilizer. We measured N and O isotope ratios in nitrate plus nitrite using cadmium and azide chemical denitrification method, and refer to the results as nitrate for brevity due to low nitrite concentrations. When examined as annual averages at each monitoring site, we found the lowest N and O isotope ratios in our only site draining native forest. All agricultural monitoring sites sit approximately on a 1:1 line, enriched in N-15 and O-18 by 2-6 per mil relative to the native forest subcatchment. The three main effluent point sources in the catchment demonstrated unexpected variability in isotope ratios. Two modern sewage treatment ponds had N and O isotope ratios close to those found in agricultural catchments, while a closed meat freezing factory effluent pond had isotope ratios strongly enriched in N-15 and O-18. The lack of summer low flows during monitoring period, combined with the variability in isotope ratios from point source, appeared to be responsible for our inability to clearly detect the effect of point sources in the isotope data from stations upstream and

A semi-analytic mathematical model for dissolved radionuclides dispersion in the Channel Isles region

Energy Technology Data Exchange (ETDEWEB)

Salomon, J.C.; Breton, M. [IFREMER, 29 - Plouzane (France). Laboratoire d`Hydrodynamique et Sedimentologie; Fraizier, A.; Bailly Du Bois, P.; Guegueniat, P. [CEA Centre de La Hague, 50 - Cherbourg-Octeville (France). Laboratoire de Radioecologie Marine

1997-12-31

A simple mathematical model for transport and mixing of dissolved substances in the Channel Isles region is based on the well known residual circulation pattern in the area. The model is relevant for time scales greater than one month. Applied to a nearly conservative element such as {sup 125}Sb, it gives an interpretation of the observed time lag between nuclear material discharges at sea and their impact on coastal waters. An evaluation is done of the efficiency of the discharge scenario by the nuclear reprocessing plant of La Hague. Given its very fast running and the possibility of being applied to any chemical or biological element present in sea water, the model seems particularly suited for ecological modelling purposes. (author) 4 refs.

A semi-analytic mathematical model for dissolved radionuclides dispersion in the Channel Isles region

International Nuclear Information System (INIS)

Salomon, J.C.; Breton, M.; Fraizier, A.; Bailly Du Bois, P.; Guegueniat, P.

1997-01-01

A simple mathematical model for transport and mixing of dissolved substances in the Channel Isles region is based on the well known residual circulation pattern in the area. The model is relevant for time scales greater than one month. Applied to a nearly conservative element such as 125 Sb, it gives an interpretation of the observed time lag between nuclear material discharges at sea and their impact on coastal waters. An evaluation is done of the efficiency of the discharge scenario by the nuclear reprocessing plant of La Hague. Given its very fast running and the possibility of being applied to any chemical or biological element present in sea water, the model seems particularly suited for ecological modelling purposes. (author)

review of the archaeological evidence for food plants from the British Isles: an example of the use of the Archaeobotanical Computer Database (ABCD

Directory of Open Access Journals (Sweden)

Philippa Tomlinson

1996-09-01

Full Text Available The Archaeobotanical Computer Database is an electronic compilation of information about remains of plants from archaeological deposits throughout the British Isles. For the first time, this wealth of published data, much of it post-dating Godwin's (1975 History of the British Flora has been brought together in a form in which the user can explore the history of a particular species or group of plants, or investigate the flora and vegetation of a particular archaeological period or part of the British Isles. The database contains information about the sites, deposits and samples from which the remains in question have been recovered, together with details of the plant parts identified and their mode of preservation. It also provides some interpretative guidance concerning the integrity of contexts and the reliability of dating as an aid to judging the quality of the data available. In this paper the compilers of the ABCD make use of the database in order to review the archaeological evidence for food plants in the British Isles. The paper begins with a definition of its scope, examining the concept of a "food plant" and the taphonomy of plant remains on British archaeological sites. It then summarises the principal changes in food plants from the prehistoric period to post-medieval times. The body of the paper is a detailed discussion of the evidence for the use of berries, other fruits, vegetables, pulses, herbs and flavourings, oil plants, cereals and nuts. Finally, the paper compares the archaeological evidence with that known from documentary sources. Readers will be able to view the archaeological evidence as distribution maps and will be able to explore aspects of the database online, enabling queries by taxa, site or worker. Instructions on obtaining electronic copies of the database tables and registering as an ABCD user are also included.

Effects of mountain tea plantations on nutrient cycling at upstream watersheds

Science.gov (United States)

Lin, T.-C.; Shaner, P.-J. L.; Wang, L.-J.; Shih, Y.-T.; Wang, C.-P.; Huang, G.-H.; Huang, J.-C.

2015-11-01

The expansion of agriculture to rugged mountains can exacerbate negative impacts of agricultural activities on ecosystem function. In this study, we monitored streamwater and rainfall chemistry of mountain watersheds at the Feitsui Reservoir Watershed in northern Taiwan to examine the effects of agriculture on watershed nutrient cycling. We found that the greater the proportion of tea plantation cover, the higher the concentrations of fertilizer-associated ions (NO3-, K+) in streamwater of the four mountain watersheds examined; on the other hand, the concentrations of the ions that are rich in soils (SO42-, Ca2+, Mg2+) did not increase with the proportion of tea plantation cover, suggesting that agriculture enriched fertilizer-associated nutrients in streamwater. Of the two watersheds for which rainfall chemistry was available, the one with higher proportion of tea plantation cover had higher concentrations of ions in rainfall and retained less nitrogen in proportion to input compared to the more pristine watershed, suggesting that agriculture can influence atmospheric deposition of nutrients and a system's ability to retain nutrients. As expected, we found that a forested watershed downstream of agricultural activities can dilute the concentrations of NO3- in streamwater by more than 70 %, indicating that such a landscape configuration helps mitigate nutrient enrichment in aquatic systems even for watersheds with steep topography. We estimated that tea plantation at our study site contributed approximately 450 kg ha-1 yr-1 of NO3-N via streamwater, an order of magnitude greater than previously reported for agricultural lands around the globe, which can only be matched by areas under intense fertilizer use. Furthermore, we constructed watershed N fluxes to show that excessive leaching of N, and additional loss to the atmosphere via volatilization and denitrification can occur under intense fertilizer use. In summary, this study demonstrated the pervasive impacts of

LA SAFE and Isle de Jean Charles: Regional Adaptation and Community Resettlement Planning

Science.gov (United States)

Sanders, M.

2017-12-01

LA SAFE, or Louisiana's Strategic Adaptations for Future Environments, is a strategic framework for community development utilizing future projections of coastal land loss and flood risk as a determining factor in regional growth management and local planning initiatives along a 10, 25, and 50 year timeline. LA SAFE utilizes the input of passionate local citizen leaders and organizations committed to enabling community members to take proactive steps towards mitigating risk and increasing resilience against coastal issues. The project aims to acknowledge that adaptation and restoration must go hand-in-hand with addressing community growth and contraction, as well as realizing Louisiana's most vulnerable coastal communities will need to contemplate resettlement over the next 50 years. The project's outlook is to become a global leader for adaptation and cultural design and restoration. Connecting a global interest with the project and offering extensive ways for people to learn about the issues and get involved will provide an immense amount of support necessary for future coastal environments around the world. This presentation will focus on the output of a year-long planning effort across a six-parish target area encompassing several vulnerable coastal Louisiana locales. The Resettlement of Isle de Jean Charles is a federally-funded and first-of-its kind initiative marking Louisiana's first attempt to relocate a vulnerable coastal community at-scale and as a group. Due to a myriad of environmental factors, the Island has experienced 98 percent land loss since 1955, leading to many of the Island's historical inhabitants to retreat to higher, drier landscapes. In moving the community at-scale, the project seeks to inject new life into the community and its residents in relocating the community to higher, safer ground, while also developing the new community in such a way that it maximizes economic development, job training, and educational opportunities and can be a

Allah in Deutschland?”: representações da comunidade islâmica na revista Der Spiegel

Directory of Open Access Journals (Sweden)

Teresa Maria Leal de Assunção Martinho Toldy

2009-09-01

Full Text Available Pretende-se apontar alguns elementos para a análise da forma como a comunidade islâmica na Alemanha é representada na revista Der Spiegel. O objetivo último é analisar como os meios de comunicação social espelham as potencialidades e os limites de alguns conceitos que têm sido fundamentais na modernidade e que parecem estar sendo questionados na pós-modernidade, nomeadamente, o próprio conceito de modernidade, mas também os de secularização e dos direitos humanos. Palavras-chave: Modernidade; colonialidade; secularização; gênero e direitos humanos. Resumen Se pretende señalar algunos elementos necesarios para analizar la manera en que la comunidad islámica en Alemania está representada en la revista Der Spiegel. El objetivo último es analizar cómo los medios de comunicación social reflejan las potencialidades y los límites de algunos conceptos que han sido fundamentales en la modernidad y que parecen estar cuestionados en la postmodernidad, principalmente el propio concepto de modernidad, pero también los conceptos de secularización y de los derechos humanos. Palabras-clave: Modernidad; colonialidad; secularización; género y derechos humanos. Abstract The text aims to identify some useful elements for the analysis of the representations of the Islamic community in Germany present in the magazine Der Spiegel. The final aim is to analyse how media reflect the potentialities and limits of some of the basic concepts of modernity which are under fire in postmodern times, such as “modernity” itself, but also “secularization” and “human rights”. Keywords: Modernity; coloniality; secularization; gender and human rights.

Environmental Assessment for Toxecon Retrofit for Mercury and Multi-Pollutant Control, Presque Isle Power Plant, Marquette, Michigan

Energy Technology Data Exchange (ETDEWEB)

N/A

2003-09-25

This Environmental Assessment (EA) evaluates environmental issues associated with constructing and operating an integrated emissions control system proposed by We Energies and its project partners with cost-shared funding support by DOE. The proposed project would be demonstrated at the existing 90-MW Units 7, 8, and 9 of We Energies' coal-fired Presque Isle Power Plant in Marquette, Michigan. The commercial-scale demonstrate would allow utilities to make decisions regarding the integrated emissions control system as a viable commercial option. DOE's share of the funding for the 5-year demonstration project would be about $25 million, while $25 million would also be provided by We Energies and its project partners. This project was selected by DOE under the Clean Coal Power Initiative (CCPI) for negotiation of a cooperative agreement to demonstrate the integration of technologies to reduce emissions of mercury (Hg) and particulate matter, as well as potentially control sulfur dioxide (SO{sub 2}), oxides of nitrogen (NO{sub x}) and hydrochloric acid (HCl) emissions. DOE's decision is whether or not to fund the project. The EA evaluates the principal environmental issues, including air quality, waste management, and traffic, that could result from construction and operation of the proposed project. The EA also considers two reasonably foreseeable scenarios that could result from the no-action alternative in which DOE would not provide cost-shared funding for the proposed project. Key findings include that potential air quality impacts resulting from the proposed project would generally be beneficial because plantwide air emissions would decrease or continue at the same level. The decrease in stack exit temperature would decrease the plume rise, which could result in increased downwind ground-level concentrations of those air pollutants experience little or no decrease in stack emissions. However, results of air dispersion modeling indicated that no

From existing in situ, high-resolution measurement technologies to lab-on-a-chip - the future of water quality monitoring?

Science.gov (United States)

Wade, A. J.; Palmer-Felgate, E. J.; Halliday, S. J.; Skeffington, R. A.; Loewenthal, M.; Jarvie, H. P.; Bowes, M. J.; Greenway, G. M.; Haswell, S. J.; Bell, I. M.; Joly, E.; Fallatah, A.; Neal, C.; Williams, R. J.; Gozzard, E.; Newman, J. R.

2012-05-01

This paper introduces new insights into the hydrochemical functioning of lowland river-systems using field-based spectrophotometric and electrode technologies. The streamwater concentrations of nitrogen species and phosphorus fractions were measured at hourly intervals on a continuous basis at two contrasting sites on tributaries of the River Thames, one draining a rural catchment, the River Enborne, and one draining a more urban system, The Cut. The measurements complement those from an existing network of multi-parameter water quality sondes maintained across the Thames catchment and weekly monitoring based on grab samples. The results of the sub-daily monitoring show that streamwater phosphorus concentrations display highly complex, seemingly chaotic, dynamics under storm conditions dependent on the antecedent catchment wetness, and that diurnal phosphorus and nitrogen cycles occur under low flow conditions. The diurnal patterns highlight the dominance of sewage inputs in controlling the streamwater phosphorus and nitrogen concentrations at low flows, even at a distance of 7 km from the nearest sewage works in the rural, River Enborne, and that the time of sample collection is important when judging water quality against ecological thresholds or standards. An exhaustion of the supply of phosphorus from diffuse and septic tank sources during storm events was evident and load estimation was not improved by sub-daily monitoring beyond that achieved by daily sampling because of the eventual reduction in the phosphorus mass entering the stream during events. The dominance of respiration over photosynthesis in The Cut indicated a prevalence of heterotrophic algae, and the seasonal patterns in respiration and photosynthesis corresponded with those of temperature and light in this nutrient over-enriched stream. These results highlight the utility of sub-daily water quality measurements but the deployment of modified wet-chemistry technologies into the field was limited

Cold-front driven storm erosion and overwash in the central part of the Isles Dernieres, a Louisiana barrier-island arc

Science.gov (United States)

Dingler, J.R.; Reiss, T.E.

1990-01-01

Tropical and extratropical storms produce significant erosion on the barrier islands of Louisiana. Over the past 100 years, such storms have produced at least 2 km of northward beach-face retreat and the loss of 63% of the surface area of the Isles Dernieres, a low-lying barrier-island arc along the central Louisiana coast. Elevations on the islands within the arc are typically less than 2 m above mean sea level. The islands typically have a washover-flat topography with occasional, poorly developed, dune-terrace topography consisting of low-lying and broken dunes. The central part of the arc consists of salt-marsh deposits overlain by washover sands along the Gulf of Mexico shoreline. Sand thicknesses range from zero behind the beach, to less than 2 m under the berm crest, and back to zero in the first nearshore trough. The sand veneer is sufficiently thin that storms can strip all the sand from the beach face, exposing the underlying marsh deposits. The geomorphic changes produced by cold fronts, a type of extratropical storm that commonly affect the Isles Dernieres between late fall and early spring are described. Between August 1986 and September 1987, repeated surveys along eleven shore-normal transects that covered 400 m of shoreline revealed the timing and extent of cold-front-produced beach change along a typical section of the central Isles Dernieres. During the study period, the beach face retreated approximately 20 m during the cold-front season but did not rebuild during the subsequent summer. Because the volume of sand deposited on the backshore (5600 m3) was less than the volume of material lost from the beach face (19,200 m3), approximately 13,600 m3 of material disappeared. Assuming that underlying marsh deposits decrease in volume in direct proportion to the amount of beach-face retreat, an estimate of the mud loss during the study period is 14,000 m3. Thus, the decrease in volume along the profiles can be accounted for without removing any sand

Iter Britannicum: Noble Visitors from the Bohemian Lands and Their Perception of the British Isles in the Second Half of 16th and Early 17th Century

Czech Academy of Sciences Publication Activity Database

Holý, Martin

2017-01-01

Roč. 4, č. 1 (2017), s. 121-133 ISSN 2333-4142 Institutional support: RVO:67985963 Keywords : Nobility * Travelling * British Isles * Early Modern Period Subject RIV: AB - History OBOR OECD: History (history of science and technology to be 6.3, history of specific sciences to be under the respective headings)

Highly discrepant proportions of female and male Scandinavian and British Isles ancestry within the isolated population of the Faroe Islands

DEFF Research Database (Denmark)

Als, Thomas Damm; TH, Jørgensen; Børglum, Anders

2006-01-01

The Faroe Islands in the North Atlantic Ocean are inhabited by a small population, whose origin is thought to date back to the Viking Age. Historical, archaeological and linguistic evidence indicates that the present population of the Faroe Islands may have a mixture of Scandinavian and British...... a frequency-based admixture approach taking private haplotypes into account by the use of phylogenetic information. While previous studies have suggested an excess of Scandinavian ancestry among the male settlers of the Faroe Islands, the current study indicates an excess of British Isles ancestry among...

21 CFR 862.1515 - Nitrogen (amino-nitrogen) test system.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nitrogen (amino-nitrogen) test system. 862.1515... Systems § 862.1515 Nitrogen (amino-nitrogen) test system. (a) Identification. A nitrogen (amino-nitrogen) test system is a device intended to measure amino acid nitrogen levels in serum, plasma, and urine...

Uptake of fertilizer nitrogen and soil nitrogen by rice using 15N-labelled nitrogen fertilizer

International Nuclear Information System (INIS)

Reddy, K.R.; Patrick, W.H. Jr.

1980-01-01

Data from five field experiments using labelled nitrogen fertilizer were used to determine the relative effects of soil nitrogen and fertilizer nitrogen on rice yield. Yield of grain was closely correlated with total aboveground nitrogen uptake (soil + fertilizer), less closely correlated with soil nitrogen uptake and not significantly correlated with fertilizer nitrogen uptake. When yield increase rather than yield was correlated with fertilizer nitrogen uptake, the correlation coefficient was statistically significant. (orig.)

Molecular nitrogen fixation and nitrogen cycle in nature

Energy Technology Data Exchange (ETDEWEB)

Virtanen, A I

1952-01-01

The origin of nitrogen oxides in the atmosphere is discussed. Evidently only a small proportion of the nitrate-and nitrite-nitrogen found in the precipitation is formed through electric discharges from molecular nitrogen, photochemical nitrogen fixation being probably of greater importance. Formation of nitrate nitrogen through atmospheric oxidation of nitrous oxide (N/sub 2/O) evaporating from the soil is also considered likely. Determination of nitrogen compounds at different altitudes is indispensable for gaining information of the N/sub 2/-fixation in the atmosphere and, in general, of the origin of nitrogen oxides and their decomposition. International cooperation is needed for this as well as for the quantitative determination of the nitrogen compounds removed from the soil by leaching and brought by waters into the seas.

The Eroticism of Artificial Flesh in Villiers de L'Isle Adam's L'Eve Future

Directory of Open Access Journals (Sweden)

Patricia Pulham

2008-10-01

Full Text Available Villiers de L'Isle Adam's 'L'Eve Future' published in 1886 features a fictional version of the inventor Thomas Edison who constructs a complex, custom-made android for Englishman Lord Ewald as a substitute for his unsatisfactory lover. Hadaly, the android, has a number of literary and cultural precursors and successors. Her most commonly accepted ancestor is Olympia in E. T. A. Hoffmann's 'The Sandman' (1816 and among her fascinating descendants are Oskar Kokoschka's 'Silent Woman'; Model Borghild, a sex doll designed by German technicians during World War II;‘Caracas' in Tommaso Landolfi's short story ‘Gogol's Wife' (1954; a variety of gynoids and golems from the realms of science fiction, including Ira Levin's 'Stepford Wives' (1972; and, most recently, that silicon masterpiece - the Real Doll. All, arguably, have their genesis in the classical myth of Pygmalion. This essay considers the tension between animation and stasis in relation to this myth, and explores the necrophiliac aesthetic implicit in Villiers's novel.

Changing politics, economics and relations on the small remote island of Fair Isle

Directory of Open Access Journals (Sweden)

Richard W. Butler

2016-11-01

Full Text Available The paper interprets changes which have taken place on Fair Isle, a small remote Scottish island, over the last half century, with a focus on how the interplay of external forces and local adjustments have produced a positive working relationship between local residents, visitors and those in authority over the island. The paper discusses the changes in the island’s governance and economy that the island residents have experienced and how life on the island has adjusted to major change over a fifty year period. The information and responses from resident surveys discussed were collected using identical household surveys conducted fifty years apart to provide a unique comparison on a longitudinal basis of changes in the economy and way of life on the island, including the emergence of tourism as the major driver of the economy This has taken place without the common antagonism or problems between residents and visitors in tourist destinations, reflecting the appropriate handling of mutual interests and concerns through political arrangements which have been supportive and sympathetic to residents and visitors.

A cross-site comparison of factors controlling streamwater carbon flux in western North American catchments (Invited)

Science.gov (United States)

Brooks, P. D.; Biederman, J. A.; Condon, K.; Chorover, J.; McIntosh, J. C.; Meixner, T.; Perdrial, J. N.

2013-12-01

Increasing variability in climate is expected to alter the amount and form of terrestrial carbon in stream water both directly, through changes in the magnitude and timing of discharge, and indirectly through changes in land cover following disturbance (e.g. drought, fire, or insect driven mortality). Predicting how these changes will impact individual stream-catchment ecosystems however, is hampered by a lack of concurrent observations on both dissolved and particulate carbon flux across a range of spatial, temporal, and discharge scales. Because carbon is strongly coupled to most biogeochemical reactions within both aquatic and terrestrial ecosystems, this represents a critical unknown in predicting the response of catchment-ecosystems to concurrent changes in climate and land cover. This presentation will address this issue using a meta-analysis of dissolved organic, dissolved inorganic, and particulate organic carbon fluxes from multiple locations, including undisturbed sites along a climate gradient from desert rivers to seasonally snow-covered, forested mountain catchments, and sites disturbed by both fire and extensive, insect driven mortality. Initial analyses suggest that dissolved (organic and inorganic) and particulate fluxes respond differently to various types of disturbance and depend on interactions between changes in size of mobile carbon pools and changes in hydrologic routing of carbon to streamwater. Anomalously large fluxes of both dissolved and particulate organic matter are associated with episodic changes in hydrologic routing (e.g. storm floods; snowmelt) that connect normally hydrologically isolated carbon pools (e.g. surficial hillslope soils) with surface water. These events are often of short duration as the supply of mobile carbon is exhausted in short term flushing response. In contrast, disturbances that increase the size of the mobile carbon pool (e.g. widespread vegetation mortality) result smaller proportional increases in

Nitrogen

Science.gov (United States)

Apodaca, Lori E.

2013-01-01

The article presents an overview of the nitrogen chemical market as of July 2013, including the production of ammonia compounds. Industrial uses for ammonia include fertilizers, explosives, and plastics. Other topics include industrial capacity of U.S. ammonia producers CF Industries Holdings Inc., Koch Nitrogen Co., PCS Nitrogen, Inc., and Agrium Inc., the impact of natural gas prices on the nitrogen industry, and demand for corn crops for ethanol production.

Sca-1+ cardiosphere-derived cells are enriched for Isl1-expressing cardiac precursors and improve cardiac function after myocardial injury.

Directory of Open Access Journals (Sweden)

Jianqin Ye

Full Text Available BACKGROUND: Endogenous cardiac progenitor cells are a promising option for cell-therapy for myocardial infarction (MI. However, obtaining adequate numbers of cardiac progenitors after MI remains a challenge. Cardiospheres (CSs have been proposed to have cardiac regenerative properties; however, their cellular composition and how they may be influenced by the tissue milieu remains unclear. METHODOLOGY/PRINCIPAL FINDING: Using "middle aged" mice as CSs donors, we found that acute MI induced a dramatic increase in the number of CSs in a mouse model of MI, and this increase was attenuated back to baseline over time. We also observed that CSs from post-MI hearts engrafted in ischemic myocardium induced angiogenesis and restored cardiac function. To determine the role of Sca-1(+CD45(- cells within CSs, we cloned these from single cell isolates. Expression of Islet-1 (Isl1 in Sca-1(+CD45(- cells from CSs was 3-fold higher than in whole CSs. Cloned Sca-1(+CD45(- cells had the ability to differentiate into cardiomyocytes, endothelial cells and smooth muscle cells in vitro. We also observed that cloned cells engrafted in ischemic myocardium induced angiogenesis, differentiated into endothelial and smooth muscle cells and improved cardiac function in post-MI hearts. CONCLUSIONS/SIGNIFICANCE: These studies demonstrate that cloned Sca-1(+CD45(- cells derived from CSs from infarcted "middle aged" hearts are enriched for second heart field (i.e., Isl-1(+ precursors that give rise to both myocardial and vascular tissues, and may be an appropriate source of progenitor cells for autologous cell-therapy post-MI.

Análisis de los efectos de la Revolución Islámica en la formulación de la política exterior de Irán hacia Estados Unidos, durante el periodo postrevolucionario (1979-1989)

OpenAIRE

Peña Borgogno, Laura Juanita

2013-01-01

La Revolución Islámica es considerada como un acontecimiento determinante para la política exterior iraní. Una de sus consecuencias directas fue el cambio radical en su formulación respecto a las potencias y a los países de su región; a partir de 1979, con la instauración del nuevo régimen islámico, se desarrolló una política que respondió a las causas revolucionarias, y se caracterizó por estar orientada a la independencia y el no alineamiento. Este documento presenta el análisis del cambio ...

Air blasts generated by rockfall impacts: Analysis of the 1996 Happy Isles event in Yosemite National Park

Science.gov (United States)

Morrissey, M. M.; Savage, W. Z.; Wieczorek, G. F.

1999-10-01

The July 10, 1996, Happy Isles rockfall in Yosemite National Park, California, released 23,000 to 38,000 m3 of granite in four separate events. The impacts of the first two events which involved a 550-m free fall, generated seismic waves and atmospheric pressure waves (air blasts). We focus on the dynamic behavior of the second air blast that downed over 1000 trees, destroyed a bridge, demolished a snack bar, and caused one fatality and several injuries. Calculated velocities for the air blast from a two-phase, finite difference model are compared to velocities estimated from tree damage. From tornadic studies of tree damage, the air blast is estimated to have traveled <108-120 m/s within 50 m from the impact and decreased to <10-20 m/s within 500 m from the impact. The numerical model simulates the two-dimensional propagation of an air blast through a dusty atmosphere with initial conditions defined by the impact velocity and pressure. The impact velocity (105-107 m/s) is estimated from the Colorado Rockfall Simulation Program that simulates rockfall trajectories. The impact pressure (0.5 MPa) is constrained by the kinetic energy of the impact (1010-1012 J) estimated from the seismic energy generated by the impact. Results from the air blast simulations indicate that the second Happy Isles air blast (weak shock wave) traveled with an initial velocity above the local sound speed. The size and location of the first impact are thought to have injected <50 wt% dust into the atmosphere. This amount of dust lowered the local atmospheric sound speed to ˜220 m/s. The discrepancy between calculated velocity data and field estimated velocity data (˜220 m/s versus ˜110 m/s) is attributed to energy dissipated by the downing of trees and additional entrainment of debris into the atmosphere not included in the calculations.

Geologic-tectonic evolutional characteristics and prospecting potential for ISL-amenable sandstone-type uranium deposits; in Sichuan basin

International Nuclear Information System (INIS)

Liu Jianhua; Zhu Xiyang; Wang Sili; Wei Jisheng

2005-01-01

Through the analysis on geologic-tectonic evolution of Sichuan basin, authors of this paper suggest: because of the heterogeneity of the basin basement and cover structures resulting from the lateral dividing, those segments in the basin that experienced only weak tectonic activation, and those that were uplifted and eroded earlier have not been intensely deformed, and have not experienced long-period burying. Rocks in those segments are poorly consolidated and there exist conditions for the formation of large-area artesian slope at the transitional sites between uplifted and subsided areas, possessing favourable hydrogeologic conditions for long-term infiltration of groundwater. These areas must be the targets for prospecting for ISL-amenable sandstone-type uranium deposits. Correspondingly, the Triassic and Jurassic where loose sand bodies are hosted are prospecting target horizons for uranium. (authors)

Forest fuel reduces the nitrogen load - calculations of nitrogen flows

International Nuclear Information System (INIS)

Burstroem, F.; Johansson, Jan.

1995-12-01

Nitrogen deposition in Sweden has increased strongly during recent decades, particularly in southern Sweden. Nitrogen appears to be largely accumulated in biomass and in the soil. It is therefore desirable to check the accumulation of nitrogen in the forest. The most suitable way of doing this is to remove more nitrogen-rich biomass from the forest, i.e., increase the removal of felling residues from final fellings and cleanings. An ecological condition for intensive removal of fuel is that the ashes are returned. The critical load for nitrogen, CL(N), indicates the level of nitrogen deposition that the forest can withstand without leading to ecological changes. Today, nitrogen deposition is higher than the CL(N) in almost all of Sweden. CL(N) is calculated in such a manner that nitrogen deposition should largely be balanced by nitrogen losses through harvesting during a forest rotation. The value of CL(N) thus largely depends on how much nitrogen is removed with the harvested biomass. When both stems and felling residues are harvested, the CL(N) is about three times higher than in conventional forestry. The increase is directly related to the amount of nitrogen in the removed biofuel. Use of biofuel also causes a certain amount of nitrogen emissions. From the environmental viewpoint there is no difference between the sources of the nitrogen compounds. An analysis of the entire fuel chain shows that, compared with the amount of nitrogen removed from the forest with the fuel, about 5 % will be emitted as nitrogen oxides or ammonia during combustion, and a further ca 5 % during handling and transports. A net amount of about 90 % of biomass nitrogen is removed from the system and becomes inert nitrogen (N 2 ). 60 refs, 3 figs, 4 tabs, 11 appendices

Delfina Serrano Ruano (éd.), Crueldad y compasíon en la literatura árabe e islámica

OpenAIRE

Clément, François

2013-01-01

Cet ouvrage constitue les actes du séminaire « Narrar y suscitar : violencia, compasíon y crueldad en la literatura árabe e islámica », qui s’est tenu en octobre 2008 à l’Institut des langues et cultures de la Méditerranée et du Proche-Orient (CCHS-CSIC, Madrid). Il s’inscrit dans le champ des recherches sur l’histoire des émotions, un domaine de plus en plus exploré (voir les travaux de C. Lutz et L. Abu-Lughod, B. H. Rosenwein, ou D. Boquet et P. Nagy), mais encore largement en friche en ce...

The response of soil and stream chemistry to decreases in acid deposition in the Catskill Mountains, New York, USA.

Science.gov (United States)

McHale, Michael R; Burns, Douglas A; Siemion, Jason; Antidormi, Michael R

2017-10-01

The Catskill Mountains have been adversely impacted by decades of acid deposition, however, since the early 1990s, levels have decreased sharply as a result of decreases in emissions of sulfur dioxide and nitrogen oxides. This study examines trends in acid deposition, stream-water chemistry, and soil chemistry in the southeastern Catskill Mountains. We measured significant reductions in acid deposition and improvement in stream-water quality in 5 streams included in this study from 1992 to 2014. The largest, most significant trends were for sulfate (SO 4 2- ) concentrations (mean trend of -2.5 μeq L -1 yr -1 ); hydrogen ion (H + ) and inorganic monomeric aluminum (Al im ) also decreased significantly (mean trends of -0.3 μeq L -1 yr -1 for H + and -0.1 μeq L -1 yr -1 for Al im for the 3 most acidic sites). Acid neutralizing capacity (ANC) increased by a mean of 0.65 μeq L -1 yr -1 for all 5 sites, which was 4 fold less than the decrease in SO 4 2- concentrations. These upward trends in ANC were limited by coincident decreases in base cations (-1.3 μeq L -1 yr -1 for calcium + magnesium). No significant trends were detected in stream-water nitrate (NO 3 - ) concentrations despite significant decreasing trends in NO 3 - wet deposition. We measured no recovery in soil chemistry which we attributed to an initially low soil buffering capacity that has been further depleted by decades of acid deposition. Tightly coupled decreasing trends in stream-water silicon (Si) (-0.2 μeq L -1 yr -1 ) and base cations suggest a decrease in the soil mineral weathering rate. We hypothesize that a decrease in the ionic strength of soil water and shallow groundwater may be the principal driver of this apparent decrease in the weathering rate. A decreasing weathering rate would help to explain the slow recovery of stream pH and ANC as well as that of soil base cations. Published by Elsevier Ltd.

Nitrogen availability for nitrogen fixing cyanobacteria upon growth ...

African Journals Online (AJOL)

The filamentous cyanobacterium Nostoc PCC 7120 is able to convert dinitrogen to ammonia in the absence of combined nitrogen. The expression of 20% of coding sequences from all major metabolic categories was examined in nitrogen fixing and non-nitrogen fixing growth conditions. The expression data were correlated ...

Experimental identification of nitrogen-vacancy complexes in nitrogen implanted silicon

Science.gov (United States)

Adam, Lahir Shaik; Law, Mark E.; Szpala, Stanislaw; Simpson, P. J.; Lawther, Derek; Dokumaci, Omer; Hegde, Suri

2001-07-01

Nitrogen implantation is commonly used in multigate oxide thickness processing for mixed signal complementary metal-oxide-semiconductor and System on a Chip technologies. Current experiments and diffusion models indicate that upon annealing, implanted nitrogen diffuses towards the surface. The mechanism proposed for nitrogen diffusion is the formation of nitrogen-vacancy complexes in silicon, as indicated by ab initio studies by J. S. Nelson, P. A. Schultz, and A. F. Wright [Appl. Phys. Lett. 73, 247 (1998)]. However, to date, there does not exist any experimental evidence of nitrogen-vacancy formation in silicon. This letter provides experimental evidence through positron annihilation spectroscopy that nitrogen-vacancy complexes indeed form in nitrogen implanted silicon, and compares the experimental results to the ab initio studies, providing qualitative support for the same.

Nitrogen nutrition effects on development, growth and nitrogen accumulation of vegetables

NARCIS (Netherlands)

Biemond, H.

1995-01-01

In order to be able to match nitrogen supply and nitrogen requirement of vegetable crops, insight is necessary in the responses to nitrogen of important processes of growth and development. This study focused on effects of amount of nitrogen applied and fractionation of nitrogen supply on

The Effect of Percentage of Nitrogen in Plasma Gas on Nitrogen ...

African Journals Online (AJOL)

Increase in nitrogen percent in the plasma gas results in increased content of dissociated nitrogen and molecular nitrogen possessing excess vibrational energy and therefore the increased solution of nitrogen in the liquid iron. It would appear that above 35% nitrogen in the plasma gas, frequency of collisions of species in ...

Archaeology. Sedimentary DNA from a submerged site reveals wheat in the British Isles 8000 years ago.

Science.gov (United States)

Smith, Oliver; Momber, Garry; Bates, Richard; Garwood, Paul; Fitch, Simon; Pallen, Mark; Gaffney, Vincent; Allaby, Robin G

2015-02-27

The Mesolithic-to-Neolithic transition marked the time when a hunter-gatherer economy gave way to agriculture, coinciding with rising sea levels. Bouldnor Cliff, is a submarine archaeological site off the Isle of Wight in the United Kingdom that has a well-preserved Mesolithic paleosol dated to 8000 years before the present. We analyzed a core obtained from sealed sediments, combining evidence from microgeomorphology and microfossils with sedimentary ancient DNA (sedaDNA) analyses to reconstruct floral and faunal changes during the occupation of this site, before it was submerged. In agreement with palynological analyses, the sedaDNA sequences suggest a mixed habitat of oak forest and herbaceous plants. However, they also provide evidence of wheat 2000 years earlier than mainland Britain and 400 years earlier than proximate European sites. These results suggest that sophisticated social networks linked the Neolithic front in southern Europe to the Mesolithic peoples of northern Europe. Copyright © 2015, American Association for the Advancement of Science.

Convertidos ao Islã: brasileiros e portugueses (Converted to Islam: Brazilians and Portuguese - DOI: 10.5752/P.2175-5841.2010v8n17p125

Directory of Open Access Journals (Sweden)

Vera Lúcia Maia Marques

2010-09-01

Full Text Available Desde o 11 de setembro de 2001, debates sobre o Islã foram intensificados, em busca de explicações plausíveis sobre os ataques terroristas ao World Trade Center. Foram colocadas em pauta, sobretudo nas mídias, nacional e internacional, hoje, uma das mais importantes fontes de informação e de construção dos nossos mundos cognitivos, questões sobre o que são os muçulmanos e o Islã. Motivada por esse cenário e pelo crescimento do número de muçulmanos no mundo, praticamente um quarto da população mundial, no qual os muçulmanos por conversão também são parte, decidi observar e comparar os dois campos, Brasil e em Portugal, tomando nota das ricas relações entre religião e cultura, entre tradição e modernidade. Dois campos com diferentes procedências, vertentes religiosas, escolas de pensamento, movimentos religiosos, que resultaram não somente em diversidade, mas igualmente em semelhança, em conflito e em dilema. De onde se observa que também a diferença une todos os muçulmanos do mundo. Palavras-chave: Islã; Muçulmanos; Convertidos.  Abstract Since September 11th 2001, debates over Islam have been intensified in search for plausible explanations for the terrorist attacks to the World Trade Center. Questions on what Muslims and Islam are have been at stake, above all, in the national and international media nowadays, one of the most important information sources as well as for building our cognitive worlds. Inspired by the scenario as well as by the growing number of Muslims in the world, almost a quarter of the population, included converted Muslims, I decided to observe and compare two fields, Brazil and Portugal, taking note about the richly relations between religion and culture, tradition and modernity. They are two fields with different origins, religious tendencies, schools of thought, religious movements, which have resulted not only in diversity, but also in similarity, conflict and dilemma. In observing

Revision of the Xenacanthida (Chondrichthyes : Elasmobranchii) from the Carboniferous of the British Isles

Energy Technology Data Exchange (ETDEWEB)

Hampe, O. [Humboldt University, Berlin (Germany)

2003-07-01

Xenacanthids were a very successful group of elasmobranchs that ranged from the Lower Carboniferous to the Upper Triassic. The history of discovery of the xenacanthids, which is closely connected with the history of coal prospecting in England, began with the finding of the type specimen of Xenacanthus laevissimus in the Westphalian B of the West Midlands. In this first review of British Carboniferous xenacanthids, the number of taxa, mainly erected during Victorian times, is reduced to 14 species distributed among six genera. Determinable remains are recorded from at least 96 localities in the British Isles. Unique characteristics of the Dinantian Diplodoselache suggest that the lineage to which this taxon belongs marks a dead end in xenacanthid evolution. This investigation also shows that the Pendleian Dicentrodus, formerly described as Cladodus, belongs to the xenacanthids. The occurrence of Orthacanthus cf. kounoviensis in the Pennines, also known from the German Saar-Nahe basin, the Saale depression and from Bohemia, indicates a faunal exchange between these intramontainous basins during the Carboniferous. The genus Triodus is identified from British deposits for the first time. A cladistic analysis of the xenacanthids suggests that they evolved from phoebodontid elasmobranchs. This analysis also confirms separation of the Middle Devonian Antarctilamna from a relationship with xenacanthid sharks.

[Effects of reduced nitrogen application and soybean intercropping on nitrogen balance of sugarcane field].

Science.gov (United States)

Liu, Yu; Zhang, Ying; Yang, Wen-ting; Li, Zhi-xian; Guan, Ao-mei

2015-03-01

A four-year (2010-2013) field experiment was carried out to explore the effects of three planting patterns (sugarcane, soybean monoculture and sugarcane-soybean 1:2 intercropping) with two nitrogen input levels (300 and 525 kg . hm-2) on soybean nitrogen fixation, sugarcane and soybean nitrogen accumulation, and ammonia volatilization and nitrogen leaching in sugarcane field. The results showed that the soybean nitrogen fixation efficiency (NFE) of sugarcane-soybean inter-cropping was lower than that of soybean monoculture. There was no significant difference in NFE among the treatments with the two nitrogen application rates. The nitrogen application rate and inter-cropping did not remarkably affect nitrogen accumulation of sugarcane and soybean. The ammonia volatilization of the reduced nitrogen input treatment was significantly lower than that of the conventional nitrogen input treatment. Furthermore, there was no significant difference in nitrogen leaching at different nitrogen input levels and among different planting patterns. The sugarcane field nitrogen balance analysis indicated that the nitrogen application rate dominated the nitrogen budget of sugarcane field. During the four-year experiment, all treatments leaved a nitrogen surplus (from 73.10 to 400.03 kg . hm-2) , except a nitrogen deficit of 66.22 kg . hm-2 in 2011 in the treatment of sugarcane monoculture with the reduced nitrogen application. The excessive nitrogen surplus might increase the risk of nitrogen pollution in the field. In conclusion, sugarcane-soybean intercropping with reduced nitrogen application is feasible to practice in consideration of enriching the soil fertility, reducing nitrogen pollution and saving production cost in sugarcane field.

Descriptions and revised key to the eggcases of the skates (Rajiformes: Rajidae) and catsharks (Carcharhiniformes: Scyliorhinidae) of the British Isles.

Science.gov (United States)

Gordon, Cat A; Hood, Ali R; Ellis, Jim R

2016-08-12

Updated descriptions and measurements for the eggcases of 10 rajiform and three scyliorhinid species occurring in the shelf seas around the British Isles are given, based on museum material, specimens collected during the 'Great Eggcase Hunt' (a Shark Trust recording project), and specimens obtained from fishery surveys. Quantitative data are given for Amblyraja radiata (n = 94), Dipturus batis (n = 24), D. cf. intermedia (n = 33), Leucoraja naevus (n = 94), Raja brachyura (n = 53), R. clavata (n = 52), R. microocellata (n = 57), R. montagui (n = 52), R. undulata (n = 52), Rostroraja alba (n = 5), Galeus melastomus (n = 7), Scyliorhinus canicula (n = 52) and S. stellaris (n = 58). An updated key for the identification of elasmobranch eggcases is provided, incorporating recent changes in skate taxonomy.

Long-term effects of changing atmospheric pollution on throughfall, bulk deposition and streamwaters in a Mediterranean forest.

Science.gov (United States)

Aguillaume, Laura; Rodrigo, Anselm; Avila, Anna

2016-02-15

The abatement programs implanted in Europe to reduce SO2, NO2 and NH3 emissions are here evaluated by analyzing the relationships between emissions in Spain and neighboring countries and atmospheric deposition in a Mediterranean forest in the Montseny mountains (NE Spain) for the last 3decades. A canopy budget model was applied to throughfall data measured during a period of high emissions (1995-1996) and a period of lower emissions (2011-2013) to estimate the changes in dry deposition over this time span. Emissions of SO2 in Spain strongly decreased (77%) and that was reflected in reductions for nssSO4(2-) in precipitation (65% for concentrations and 62% for SO4(2)-S deposition). A lower decline was found for dry deposition (29%). Spanish NO2 emissions increased from 1980 to 1991, remained constant until 2005, and decreased thereafter, a pattern that was paralleled by NO3(-) concentrations in bulk precipitation at Montseny. This pattern seems to be related to a higher share of renewable energies in electricity generation in Spain in recent years. However, dry deposition increased markedly between 1995 and 2012, from 1.3 to 6.7 kg ha(-1) year(-)(1). Differences in meteorology between periods may have had a role, since the recent period was drier thus probably favoring dry deposition. Spanish NH3 emissions increased by 13% between 1980 and 2012 in Spain but NH4(+) concentrations in precipitation and NH4(+)-N deposition showed a decreasing trend (15% reduction) at Montseny, probably linked to the reduction ammonium sulfate and nitrate aerosols to be scavenged by rainfall. NH4(+)-N dry deposition was similar between the compared periods. The N load at Montseny (15-17 kg ha(-1)y ear(-1)) was within the critical load range proposed for Mediterranean sclerophyllous forests (15-17.5 kg ha(-1) year(-1)). The onset of N saturation is suggested by the observed increasing N export in streamwaters. Copyright © 2015 Elsevier B.V. All rights reserved.

Foliage nitrogen turnover: differences among nitrogen absorbed at different times by Quercus serrata saplings

Science.gov (United States)

Ueda, Miki U.; Mizumachi, Eri; Tokuchi, Naoko

2011-01-01

Background and Aims Nitrogen turnover within plants has been intensively studied to better understand nitrogen use strategies. However, differences among the nitrogen absorbed at different times are not completely understood and the fate of nitrogen absorbed during winter is largely uncharacterized. In the present study, nitrogen absorbed at different times of the year (growing season, winter and previous growing season) was traced, and the within-leaf nitrogen turnover of a temperate deciduous oak Quercus serrata was investigated. Methods The contributions of nitrogen absorbed at the three different times to leaf construction, translocation during the growing season, and the leaf-level resorption efficiency during leaf senescence were compared using 15N. Key Results Winter- and previous growing season-absorbed nitrogen significantly contributed to leaf construction, although the contribution was smaller than that of growing season-absorbed nitrogen. On the other hand, the leaf-level resorption efficiency of winter- and previous growing season-absorbed nitrogen was higher than that of growing season-absorbed nitrogen, suggesting that older nitrogen is better retained in leaves than recently absorbed nitrogen. Conclusions The results demonstrate that nitrogen turnover in leaves varies with nitrogen absorption times. These findings are important for understanding plant nitrogen use strategies and nitrogen cycles in forest ecosystems. PMID:21515608

Marine nitrogen cycle

Digital Repository Service at National Institute of Oceanography (India)

Naqvi, S.W.A.

) such as the Marine nitrogen cycle The marine nitrogen cycle. ‘X’ and ‘Y’ are intra-cellular intermediates that do not accumulate in water column. (Source: Codispoti et al., 2001) Page 1 of 3Marine nitrogen cycle - Encyclopedia of Earth 11/20/2006http://www... and nitrous oxide budgets: Moving targets as we enter the anthropocene?, Sci. Mar., 65, 85-105, 2001. Page 2 of 3Marine nitrogen cycle - Encyclopedia of Earth 11/20/2006http://www.eoearth.org/article/Marine_nitrogen_cycle square6 Gruber, N.: The dynamics...

Nitrogen excess in North American ecosystems: Predisposing factors, ecosystem responses, and management strategies

Science.gov (United States)

Fenn, M.E.; Poth, M.A.; Aber, J.D.; Baron, Jill S.; Bormann, B.T.; Johnson, D.W.; Lemly, A.D.; McNulty, S.G.; Ryan, D.F.; Stottlemyer, R.

1998-01-01

Most forests in North America remain nitrogen limited, although recent studies have identified forested areas that exhibit symptoms of N excess, analogous to overfertilization of arable land. Nitrogen excess in watersheds is detrimental because of disruptions in plant/soil nutrient relations, increased soil acidification and aluminum mobility, increased emissions of nitrogenous greenhouse gases from soil, reduced methane consumption in soil, decreased water quality, toxic effects on freshwater biota, and eutrophication of coastal marine waters. Elevated nitrate (NO3/-) loss to groundwater or surface waters is the primary symptom of N excess. Additional symptoms include increasing N concentrations and higher N:nutrient ratios in foliage (i.e., N:Mg, N:P), foliar accumulation of amino acids or NO3/-, and low soil C:N ratios. Recent nitrogen-fertilization studies in New England and Europe provide preliminary evidence that some forests receiving chronic N inputs may decline in productivity and experience greater mortality. Long-term fertilization at Mount Ascutney, Vermont, suggests that declining and slow N-cycling coniferous stands may be replaced by fast-growing and fast N-cycling deciduous forests. Symptoms of N saturation are particularly severe in high-elevation, nonaggrading spruce-fir ecosystems in the Appalachian Mountains and in eastern hardwood watersheds at the Fernow Experimental Forest near Parsons, West Virginia. In the Los Angeles Air Basin, mixed conifer forests and chaparral watersheds with high smog exposure are N saturated and exhibit the highest streamwater NO3/- concentrations for wildlands in North America. High-elevation alpine watersheds in the Colorado Front Range and a deciduous forest in Ontario, Canada, are N saturated, although N deposition is moderate (~8 kg??ha-1??yr-1). In contrast, the Harvard Forest hardwood stand in Massachusetts has absorbed >900 kg N/ha during 8 yr of N amendment studies without significant NO3/- leaching

Effects of nitrogen applocation on yield and nitrogen accumulation in soybean

International Nuclear Information System (INIS)

Di Wei; Jin Xijun; Ma Chunmei; Dong Shoukun; Gong Zhenping; Zhang Lei

2010-01-01

Methods of sand cultre and 15 N tracing were used to study the effects of nitrogen application on yield and nitrogen accumulation in soybean variety SN 14 . The results showed as follows: accumulated nitrogen in the whole plant, petiole, pod shell and seed increased at the beginning and then decreased with the increase of nitrogen levels; Nitrogen accumulation in leaf and stem increased in 3 and 5 times for N 150 than that of N 0 , which indicated that high nitrogen levels promoted the nitrogen accumulation in leaf and stem, however compared with N 0 , nitrogen accumulation in root, Nodulation-N accumulated in the whole plant and seed of N 150 decreased by 60.3%, 74. 9% and 85.7% respectively, and Fertilizer-N harvest index of N 150 decreased, which was 19.8% lower than that of N 50 , as well as Nodulation-N harvest index 25.5% lower than that of N 50 . The nitrogen levels of soybean yield also firstly increased and then decreased; Compared with N 0 , plant height, pod height and lowest pod nodes of soybean treated with N 150 increased by 55.2%, 199.7% and 142.9% respectively, while no effects were found on node number. (authors)

Nitrogen and Oxygen Isotopic Studies of the Marine Nitrogen Cycle.

Science.gov (United States)

Casciotti, Karen L

2016-01-01

The marine nitrogen cycle is a complex web of microbially mediated reactions that control the inventory, distribution, and speciation of nitrogen in the marine environment. Because nitrogen is a major nutrient that is required by all life, its availability can control biological productivity and ecosystem structure in both surface and deep-ocean communities. Stable isotopes of nitrogen and oxygen in nitrate and nitrite have provided new insights into the rates and distributions of marine nitrogen cycle processes, especially when analyzed in combination with numerical simulations of ocean circulation and biogeochemistry. This review highlights the insights gained from dual-isotope studies applied at regional to global scales and their incorporation into oceanic biogeochemical models. These studies represent significant new advances in the use of isotopic measurements to understand the modern nitrogen cycle, with implications for the study of past ocean productivity, oxygenation, and nutrient status.

Tightening the nitrogen cycle

OpenAIRE

Christensen, B.T.

2004-01-01

The availability of nitrogen to crop plants is a universally important aspect of soil quality, and often nitrogen represents the immediate limitation to crop productivity in modern agriculture. Nitrogen is decisive for the nutritive value of plant products and plays a key role in the environmental impact of agricultural production. The fundamental doctrine of nitrogen management is to optimise the nitrogen use efficiency of both introduced and native soil nitrogen by increasing the temporal a...

Formation mechanism of self-potential at ISL-amenable interlayer oxidation zone sandstone-type uranium deposit and the simulation and application of self-potential anomalies

International Nuclear Information System (INIS)

Tang Hongzhi; Liu Qingcheng; Su Zhaofeng; Gong Yuling

2006-01-01

Based on the analysis of geochemical characteristics and metallogenic physico-chemical conditions of ISL-amenable sandstone-type uranium deposits, the formation mechanism of self-potential field is discussed, a mathematic calculation model has been set up, and the simulation calculation has been performed for self-potential anomalies above uranium ore bodies of ordinary form, features of survey curve are analysed and methods for correcting topography at self-potential anomalies are discussed, and a simulation curve of self-potential in the area of slope topography has been presented. Finally, the availability of the method is demonstrated by an example. (authors)

Biome-scale nitrogen fixation strategies selected by climatic constraints on nitrogen cycle.

Science.gov (United States)

Sheffer, Efrat; Batterman, Sarah A; Levin, Simon A; Hedin, Lars O

2015-11-23

Dinitrogen fixation by plants (in symbiosis with root bacteria) is a major source of new nitrogen for land ecosystems(1). A long-standing puzzle(2) is that trees capable of nitrogen fixation are abundant in nitrogen-rich tropical forests, but absent or restricted to early successional stages in nitrogen-poor extra-tropical forests. This biome-scale pattern presents an evolutionary paradox(3), given that the physiological cost(4) of nitrogen fixation predicts the opposite pattern: fixers should be out-competed by non-fixers in nitrogen-rich conditions, but competitively superior in nitrogen-poor soils. Here we evaluate whether this paradox can be explained by the existence of different fixation strategies in tropical versus extra-tropical trees: facultative fixers (capable of downregulating fixation(5,6) by sanctioning mutualistic bacteria(7)) are common in the tropics, whereas obligate fixers (less able to downregulate fixation) dominate at higher latitudes. Using a game-theoretic approach, we assess the ecological and evolutionary conditions under which these fixation strategies emerge, and examine their dependence on climate-driven differences in the nitrogen cycle. We show that in the tropics, transient soil nitrogen deficits following disturbance and rapid tree growth favour a facultative strategy and the coexistence of fixers and non-fixers. In contrast, sustained nitrogen deficits following disturbance in extra-tropical forests favour an obligate fixation strategy, and cause fixers to be excluded in late successional stages. We conclude that biome-scale differences in the abundance of nitrogen fixers can be explained by the interaction between individual plant strategies and climatic constraints on the nitrogen cycle over evolutionary time.

Nitrogen supply of crops by biological nitrogen fixation. 2

International Nuclear Information System (INIS)

Jensen, E.S.; Andersen, A.J.; Soerensen, H.; Thomsen, J.D.

1985-02-01

In the present work the contributions from combined N-sources and symbiotic nitrogen fixation to the nitrogen supply of field-grown peas and field beans were evaluated by means of 15 N fertilizer dilution. The effect of N-fertilizer, supplied at sowing and at different stages of plant development, on nitrogen fixation, yield and protein production in peas, was studied in pot experiments. (author)

Impact of CO2 emissions on the geoecological state of landscapes of the British Isles: carbon footprint versus the assimilation potential

Science.gov (United States)

Romanova, Emma; Bulokhov, Anton; Arshinova, Marina

2017-04-01

The geoecological state of landscapes is determined by the type and intensity of anthropogenic impacts, the ability of geosystems to sustain them and the number of population living within a particular landscape unit. The main sources of CO2 emissions are thermal power plants, industrial facilities, transport and waste utilization. In Great Britain 163 enterprises produce 254.7 MMT CO2Eq. and 20 enterprises in Ireland - 17.8 MMT CO2Eq. Total transport emissions are 122 MMT CO2Eq. Utilization of solid wastes collected on the British Isles produces about 4.2 MMT CO2Eq. The spatial pattern of CO2 sources within the landscapes is particularly mosaic. Among the indicators which characterize the capacity of landscapes to neutralize wastes the assimilation potential (AP) is particularly important. The neutralization is based on the process of sequestration of gaseous substances, i.e. their accumulation in leaves, branches and stocks during respiration and growth of trees and in water bodies by aquatic organisms. Thus the AP is calculated basing on the area of forests and wetlands which perform the regulating services in landscapes. Total absorbing capacity of forests of the British Isles is 6.805 MMT CO2Eq. Inland waters cover 0.01% of the territory and their assimilating role is minor. The evaluation procedure includes several analytical steps: 1) inventory of the volumes of CO2 emissions by all anthropogenic sources within the borders of natural geosystems; 2) calculation of the area of CO2 assimilation in landscapes and the maximum possible volumes of CO2 sequestration; 3) comparison of the volumes of emissions and the assimilation potential of each landscape, classification of landscapes into debtors (with the deficit of AP) and creditors (with surplus AP); 4) calculation of population in each landscape; 5) risk assessment for the inhabitants living within landscapes-debtors; 6) classification and mapping of landscapes according to their geoecological state. The

Exogenous trehalose improves growth under limiting nitrogen through upregulation of nitrogen metabolism.

Science.gov (United States)

Lin, Yingchao; Zhang, Jie; Gao, Weichang; Chen, Yi; Li, Hongxun; Lawlor, David W; Paul, Matthew J; Pan, Wenjie

2017-12-19

The trehalose (Tre) pathway has strong effects on growth and development in plants through regulation of carbon metabolism. Altering either Tre or trehalose 6-phosphate (T6P) can improve growth and productivity of plants as observed under different water availability. As yet, there are no reports of the effects of modification of Tre orT6P on plant performance under limiting nutrition. Here we report that nitrogen (N) metabolism is positively affected by exogenous application of Tre in nitrogen-deficient growing conditions. Spraying foliage of tobacco (Nicotiana tabacum) with trehalose partially alleviated symptoms of nitrogen deficiency through upregulation of nitrate and ammonia assimilation and increasing activities of nitrate reductase (NR), glycolate oxidase (GO), glutamine synthetase (GS) and glutamine oxoglutarate aminotransferase (GOGAT) with concomitant changes in ammonium (NH 4 + ) and nitrate (NO 3 - ) concentrations, glutamine and amino acids. Chlorophyll and total nitrogen content of leaves and rates of photosynthesis were increased compared to nitrogen-deficient plants without applied Tre. Total plant biomass accumulation was also higher in Tre -fed nitrogen-deficient plants, with a smaller proportion of dry weight partitioned to roots, compared to nitrogen-deficient plants without applied Tre. Consistent with higher nitrogen assimilation and growth, Tre application reduced foliar starch. Minimal effects of Tre feeding were observed on nitrogen-sufficient plants. The data show, for the first time, significant stimulatory effects of exogenous Tre on nitrogen metabolism and growth in plants growing under deficient nitrogen. Under such adverse conditions metabolism is regulated for survival rather than productivity. Application of Tre can alter this regulation towards maintenance of productive functions under low nitrogen. This has implications for considering approaches to modifying the Tre pathway for to improve crop nitrogen-use efficiency and

Population Structure and Abundance of Arsenite-Oxidizing Bacteria along an Arsenic Pollution Gradient in Waters of the Upper Isle River Basin, France▿ †

Science.gov (United States)

Quéméneur, Marianne; Cébron, Aurélie; Billard, Patrick; Battaglia-Brunet, Fabienne; Garrido, Francis; Leyval, Corinne; Joulian, Catherine

2010-01-01

Denaturing gradient gel electrophoresis (DGGE) and quantitative real-time PCR (qPCR) were successfully developed to monitor functional aoxB genes as markers of aerobic arsenite oxidizers. DGGE profiles showed a shift in the structure of the aoxB-carrying bacterial population, composed of members of the Alpha-, Beta- and Gammaproteobacteria, depending on arsenic (As) and Eh levels in Upper Isle River Basin waters. The highest aoxB gene densities were found in the most As-polluted oxic surface waters but without any significant correlation with environmental factors. Arsenite oxidizers seem to play a key role in As mobility in As-impacted waters. PMID:20453153

The nitrogen cycle.

Science.gov (United States)

Stein, Lisa Y; Klotz, Martin G

2016-02-08

Nitrogen is the fourth most abundant element in cellular biomass, and it comprises the majority of Earth's atmosphere. The interchange between inert dinitrogen gas (N2) in the extant atmosphere and 'reactive nitrogen' (those nitrogen compounds that support, or are products of, cellular metabolism and growth) is entirely controlled by microbial activities. This was not the case, however, in the primordial atmosphere, when abiotic reactions likely played a significant role in the inter-transformation of nitrogen oxides. Although such abiotic reactions are still important, the extant nitrogen cycle is driven by reductive fixation of dinitrogen and an enzyme inventory that facilitates dinitrogen-producing reactions. Prior to the advent of the Haber-Bosch process (the industrial fixation of N2 into ammonia, NH3) in 1909, nearly all of the reactive nitrogen in the biosphere was generated and recycled by microorganisms. Although the Haber-Bosch process more than quadrupled the productivity of agricultural crops, chemical fertilizers and other anthropogenic sources of fixed nitrogen now far exceed natural contributions, leading to unprecedented environmental degradation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nitrogen uptake and fertilizer nitrogen use efficiency of wheat under different soil water conditions

International Nuclear Information System (INIS)

Wang Baiqun; Zhang Wei; Yu Cunzu

1999-01-01

The pot experiment was conducted to study the effects of soil water regime and fertilizer nitrogen rate on the yields, nitrogen uptake and fertilizer nitrogen utilization of wheat by using 15 N tracer method. The results showed that the aboveground biomass, stem yield and grain yield increased with the increase of soil moisture in the fertilizer nitrogen treatments. All the yield increased with the increase of the fertilizer nitrogen rate in the soil water treatments. It was found that both soil water regime and fertilizer nitrogen rate significantly influenced the amount of nitrogen uptake by wheat according to the variance analysis. The amount of nitrogen uptake increased with the rise of the soil moisture in fertilizer nitrogen treatments and the amount also increased with the increase of the urea nitrogen rate in the soil water regime. Soil water regimes not only had an impact on nitrogen uptake but also had a close relationship with soil nitrogen supply and fertilizer nitrogen use efficiency. The soil A values decreased in urea treatment and increased with the rise of the soil moisture in the combination treatment of urea with pig manure. The fertilizer nitrogen use efficiency rose with the rise of the soil moisture in the same fertilizer nitrogen treatment. The fertilizer nitrogen use efficiency of the urea treatment was 13.3%, 27.9% and 32.3% in the soils with 50%, 70% and 90% of the field water capacity, respectively. The fertilizer nitrogen use efficiency in the combination treatment of urea with pig manure was 20.0%, 29.9% and 34.4% in the soils of above three levels, respectively. It was concluded that the low soil moisture restricted urea nitrogen use efficiency (UNUE) and the UNUE could be raised by combination treatment of urea with manure in the soil of enough moisture

Nitrogen utilization efficiency and nitrogen nutrition of rice crops at MADA using the microplot nitrogen balance method

International Nuclear Information System (INIS)

Ahmad Nazrul Abd Wahid; Abdul Razak Ruslan; Latiffah Norddin; Hazlina Abdullah; Khairuddin Abdul Rahim

2004-01-01

Nitrogen (N) is a very important nutrient for rice crops and is a main component of protein. Nitrogen is essential in the production of plant chlorophyll and involves in vegetative and fruit growth and development processes. Nitrogen is a critical input and exert high cost in rice crop production. Nitrogen fertilizer is not fully utilised by the rice crop; some is lost due the processes of vaporization, hydrolysis, erosion, leaching and used by other plants and microorganisms. Several agronomic practices have been studied and adopted in this country with the purpose of increasing the efficiency nitrogen fertilizer utilization and thus, reducing the output cost for rice crops. The microplot nitrogen balance method is one of the methods used to determine uptake efficiency of nitrogen fertilizers by rice crops. In this research, the microplot of 1 m x 1 m squares in paddy plot were used, to ensure that sequential sampling was done at predetermined areas. Scheduled monthly sampling of soil and rice crops was conducted until the mature stage, harvest and post-harvest period. This MINT-MADA cooperative project contains the elements of information sharing on fertilizer efficiency measurement methods by using the N-15 isotopic tracer technique and the N-balance technique in soil, besides the cooperation on use of infrastructure and facilities, expertise and labour. (Author)

Nitrogen concentrations in mosses indicate the spatial distribution of atmospheric nitrogen deposition in Europe

International Nuclear Information System (INIS)

Harmens, H.; Norris, D.A.; Cooper, D.M.; Mills, G.; Steinnes, E.; Kubin, E.; Thoeni, L.; Aboal, J.R.; Alber, R.; Carballeira, A.; Coskun, M.; De Temmerman, L.; Frolova, M.; Gonzalez-Miqueo, L.

2011-01-01

In 2005/6, nearly 3000 moss samples from (semi-)natural location across 16 European countries were collected for nitrogen analysis. The lowest total nitrogen concentrations in mosses ( 2 = 0.91) linear relationship was found between the total nitrogen concentration in mosses and measured site-specific bulk nitrogen deposition rates. The total nitrogen concentrations in mosses complement deposition measurements, helping to identify areas in Europe at risk from high nitrogen deposition at a high spatial resolution. - Highlights: → Nitrogen concentrations in mosses were determined at ca. 3000 sites across Europe. → Moss concentrations were compared with EMEP modelled nitrogen deposition. → The asymptotic relationship for Europe showed saturation at ca. 15 kg N ha -1 y -1 . → Linear relationships were found with measured nitrogen deposition in some countries. → Moss concentrations complement deposition measurements at high spatial resolution. - Mosses as biomonitors of atmospheric nitrogen deposition in Europe.

Dissolved organic nitrogen recalcitrance and bioavailable nitrogen quantification for effluents from advanced nitrogen removal wastewater treatment facilities

International Nuclear Information System (INIS)

Fan, Lu; Brett, Michael T.; Jiang, Wenju; Li, Bo

2017-01-01

The objective of this study was to determine the composition of nitrogen (N) in the effluents of advanced N removal (ANR) wastewater treatment plants (WWTPs). This study also tested two different experimental protocols for determining dissolved N recalcitrance. An analysis of 15 effluent samples from five WWTPs, showed effluent concentrations and especially effluent composition varied greatly from one system to the other, with total nitrogen (TN) ranging between 1.05 and 8.10 mg L −1 . Nitrate (NO 3 − ) accounted for between 38 ± 32% of TN, and ammonium accounted for a further 29 ± 28%. All of these samples were dominated by dissolved inorganic nitrogen (DIN; NO 3 −  + NH 4 + ), and uptake experiments indicated the DIN fraction was as expected highly bioavailable. Dissolved organic N (DON) accounted for 20 ± 11% for the total dissolved N in these effluents, and uptake experiments indicated the bioavailability of this fraction varied between 27 ± 26% depending on the WWTP assessed. These results indicate near complete DIN removal should be the primary goal of ANR treatment systems. The comparison of bioavailable nitrogen (BAN) quantification protocols showed that the dissolved nitrogen uptake bioassay approach was clearly a more reliable way to determine BAN concentrations compared to the conventional cell yield protocol. Moreover, because the nitrogen uptake experiment was much more sensitive, this protocol made it easier to detect extrinsic factors (such as biological contamination or toxicity) that could affect the accuracy of these bioassays. Based on these results, we recommend the nitrogen uptake bioassay using filtered and autoclaved samples to quantify BAN concentrations. However, for effluent samples indicating toxicity, algal bioassays will not accurately quantify BAN. - Highlights: • DIN was the dominated N pool for most of the tested effluent samples. • DON bioavailability considerably varied depending on the WWTP assessed. �

[Effects of nitrogen and irrigation water application on yield, water and nitrogen utilization and soil nitrate nitrogen accumulation in summer cotton].

Science.gov (United States)

Si, Zhuan Yun; Gao, Yang; Shen, Xiao Jun; Liu, Hao; Gong, Xue Wen; Duan, Ai Wang

2017-12-01

A field experiment was carried out to study the effects of nitrogen and irrigation water application on growth, yield, and water and nitrogen use efficiency of summer cotton, and to develop the optimal water and nitrogen management model for suitable yield and less nitrogen loss in summer cotton field in the Huang-Huai region. Two experimental factors were arranged in a split plot design. The main plots were used for arranging nitrogen factor which consisted of five nitrogen fertilizer le-vels(0, 60, 120, 180, 240 kg·hm -2 , referred as N 0 , N 1 , N 2 , N 3 , N 4 ), and the subplots for irrigation factor which consisted of three irrigation quota levels (30, 22.5, 15 mm, referred as I 1 , I 2 , I 3 ). There were 15 treatments with three replications. Water was applied with drip irrigation system. Experimental results showed that both irrigation and nitrogen fertilization promoted cotton growth and yield obviously, but nitrogen fertilizer showed more important effects than irrigation and was the main factor of regulating growth and yield of summer cotton in the experimental region. With the increase of nitrogen fertilization rate and irrigation amount, the dry mater accumulation of reproductive organs, the above-ground biomass at the flowering-bolling stage and seed cotton yield increased gradually, reached peak values at nitrogen fertilization rate of 180 kg·hm -2 and decreased slowly with the nitrogen fertilization rate further increased. The maximum yield of 4016 kg·hm -2 was observed in the treatment of N 3 I 1 . Increasing nitrogen fertilizer amount would improve significantly total N absorption of shoots and N content of stem and leaf, but decrease nitrogen partial factor productivity. The maximum irrigation-water use efficiency of 5.40 kg·m -3 and field water use efficiency of 1.24 kg·m -3 were found in the treatments of N 3 I 3 and N 3 I 1 , respectively. With increasing nitrogen fertilization amount, soil NO 3 - -N content increased and the main soil

[Characteristics of dry matter production and nitrogen accumulation in barley genotypes with high nitrogen utilization efficiency].

Science.gov (United States)

Huang, Yi; Li, Ting-Xuan; Zhang, Xi-Zhou; Ji, Lin

2014-07-01

A pot experiment was conducted under low (125 mg x kg-1) and normal (250 mg x kg(-1)) nitrogen treatments. The nitrogen uptake and utilization efficiency of 22 barley cultivars were investigated, and the characteristics of dry matter production and nitrogen accumulation in barley were analyzed. The results showed that nitrogen uptake and utilization efficiency were different for barley under two nitrogen levels. The maximal values of grain yield, nitrogen utilization efficiency for grain and nitrogen harvest index were 2.87, 2.91 and 2.47 times as those of the lowest under the low nitrogen treatment. Grain yield and nitrogen utilization efficiency for grain and nitrogen harvest index of barley genotype with high nitrogen utilization efficiency were significantly greater than low nitrogen utilization efficiency, and the parameters of high nitrogen utilization efficiency genotype were 82.1%, 61.5% and 50.5% higher than low nitrogen utilization efficiency genotype under the low nitrogen treatment. Dry matter mass and nitrogen utilization of high nitrogen utilization efficiency was significantly higher than those of low nitrogen utilization efficiency. A peak of dry matter mass of high nitrogen utilization efficiency occurred during jointing to heading stage, while that of nitrogen accumulation appeared before jointing. Under the low nitrogen treatment, dry matter mass of DH61 and DH121+ was 34.4% and 38.3%, and nitrogen accumulation was 54. 8% and 58.0% higher than DH80, respectively. Dry matter mass and nitrogen accumulation seriously affected yield before jointing stage, and the contribution rates were 47.9% and 54.7% respectively under the low nitrogen treatment. The effect of dry matter and nitrogen accumulation on nitrogen utilization efficiency for grain was the largest during heading to mature stages, followed by sowing to jointing stages, with the contribution rate being 29.5% and 48.7%, 29.0% and 15.8%, respectively. In conclusion, barley genotype with high

The response of soil and stream chemistry to decreases in acid deposition in the Catskill Mountains, New York, USA

Science.gov (United States)

McHale, Michael; Burns, Douglas A.; Siemion, Jason; Antidormi, Michael

2017-01-01

The Catskill Mountains have been adversely impacted by decades of acid deposition, however, since the early 1990s, levels have decreased sharply as a result of decreases in emissions of sulfur dioxide and nitrogen oxides. This study examines trends in acid deposition, stream-water chemistry, and soil chemistry in the southeastern Catskill Mountains. We measured significant reductions in acid deposition and improvement in stream-water quality in 5 streams included in this study from 1992 to 2014. The largest, most significant trends were for sulfate (SO42−) concentrations (mean trend of −2.5 μeq L−1 yr−1); hydrogen ion (H+) and inorganic monomeric aluminum (Alim) also decreased significantly (mean trends of −0.3 μeq L−1 yr−1 for H+ and −0.1 μeq L−1 yr−1 for Alim for the 3 most acidic sites). Acid neutralizing capacity (ANC) increased by a mean of 0.65 μeq L−1 yr−1 for all 5 sites, which was 4 fold less than the decrease in SO42−concentrations. These upward trends in ANC were limited by coincident decreases in base cations (−1.3 μeq L−1 yr−1 for calcium + magnesium). No significant trends were detected in stream-water nitrate (NO3−) concentrations despite significant decreasing trends in NO3− wet deposition. We measured no recovery in soil chemistry which we attributed to an initially low soil buffering capacity that has been further depleted by decades of acid deposition. Tightly coupled decreasing trends in stream-water silicon (Si) (−0.2 μeq L−1 yr−1) and base cations suggest a decrease in the soil mineral weathering rate. We hypothesize that a decrease in the ionic strength of soil water and shallow groundwater may be the principal driver of this apparent decrease in the weathering rate. A decreasing weathering rate would help to explain the slow recovery of stream pH and ANC as well as that of soil base cations.

A study of geographical variations in the concentrations of plutonium and radiostrontium in human teeth throughout the British Isles

International Nuclear Information System (INIS)

O'Donnell, Rauiri

1993-05-01

Concern has been expressed about the impact on humans of plutonium and radiostrontium releases from nuclear installations in the United Kingdom, with public interest focusing on reported leukaemia clusters in the vicinity of some of these installations. In particular, it is not clear whether such discharges result in and increase in the body burden of plutonium and radiostrontium (present as a consequence of global fallout) in the local population. In this collaborative study the comparative exposures to 239,240Pu and 90Sr of different geographically located child populations in the British Isles have been examined using teeth removed from children for orthodontic purposes. Minute traces on 239,240Pu were found to be present in children's teeth. The overall mean concentration was 5+4 mBq/kg (ash), which is three orders of magnitude lower than reported total activities. Approximately 75% of the samples analysed showed concentrations below the mean value. Although there is considerable scatter in the data, there is some evidence of a marginal enhancement in the 239,240Pu concentration measured in the general vicinity of Cumbria, where the BNF plc. nuclear fuel reprocessing complex is located. Concentrations of 90Sr in teeth exceeded those of plutonium by three orders of magnitude, the overall mean being 8+5Bq/kg (ash). However, there was no evidence of any enhancement in the levels throughout Cumbria. No correlation was observed between 239,240Pu or 90Sr concentrations and mean annual rainfall, not was there any correlation between the levels of these radionuclides in the same samples. The plutonium and radiostrontium concentrations measured in teeth are similar to those reported for human bone in the British Isles and suggests that teeth can be used as an indicator of skeletal burden. On the basis of the above mentioned data, estimates have been made of the approximate risks of leukaemia and non-Hodgkins lymphoma assuming chronic intakes of these radionuclides. The

Replenishment and mobilization of intracellular nitrogen pools decouples wine yeast nitrogen uptake from growth

OpenAIRE

SANCHO FORNER, MARTA; Alicia Gutiérrez; BELTRAN CASELLAS, GEMMA; José Manuel Guillamon; Jonas Warringer

2016-01-01

Wine yeast capacity to take up nitrogen from the environment and catabolize it to support population growth, fermentation, and aroma production is critical to wine production. Under nitrogen restriction, yeast nitrogen uptake is believed to be intimately coupled to reproduction with nitrogen catabolite repression (NCR) suggested mediating this link. We provide a time- and strain-resolved view of nitrogen uptake, population growth, and NCR activity in wine yeasts. Nitrogen uptake was found to ...

Effectiveness of Ammonium-Nitrogen and Nitrate-Nitrogen in Irrigation Water in Paddy Rice without Topdressed Nitrogen at the Panicle Formation Stage

OpenAIRE

池田, 元輝; 渡辺, 孝賢; Ikeda, Motoki; Watanabe, Takayasu

2002-01-01

A pot experiment was conducted to evaluate the efficiency of ammonium- and nitrate- nitrogen contained in irrigation water during the reproductive growth period of paddy rice （Oryza sativa L. cv. Hinohikari） that did not receive topdressed nitrogen at the panicle formation stage. lrrigation of water containing a low level of nitrogen （7mgNL^-1） did not increase yields so much compared to topdressed nitrogen. lrrigation of water containing a high level of nitrogen （14mgNL^-1） caused substantia...

Tsunami Evacuation Exercises: the Case of Heraklion, Crete Isl., Greece

Science.gov (United States)

Triantafyllou, I.; Charalampakis, M.; Bocchini, G. M.; Novikova, T.; Papadopoulos, G. A.

2016-12-01

Effective tsunami evacuation requires appropriate awareness as regards good shelters selection. Field exercises may improve public awareness. A field exercise was organized in Heraklion, Crete Isl., in 2016. The area is part of the Hellenic Arc which is the most active structure in the Mediterranean. Large earthquakes triggered tsunamis that hit Heraklion in the past, such in AD 1303. After selecting various fault models, simulation of the 1303 tsunami showed important inundation zone in Heraklion. For the exercise needs a team of 30 volunteers was divided in 3 groups of 10 people each. Everyone was equipped with a mobile phone and a GPS device. The 3 groups were gathered in 3 coastal spots Heraklion situated 400 m apart each other. The scenario was that immediately after receiving in their mobile a tsunami warning message they will set on their personal GPS device and start evacuating inland on the best way they believed to do so. In each group, only 5 out of 10 volunteers were notified beforehand that the Eleftherias Square, located inland at distance satisfying evacuation needs in case of repeat of the 1303 tsunami, would be a good shelter to go. Using the Road Graph Plugin of QGIS, we calculated the shortest path distances which found equal to 800, 700 and 680 m. Adopting average velocity of 3 km/h we found that these distances can be covered within 18, 16 and 15 min, respectively. The routes towards the settlement spots as well as the times needed to arrive there by each one of the 30 volunteers were recorded by their personal GPS devices. The processing of the GPS tracks and their comparison with the theoretical routes and times showed good evacuation performance which is encouraging for the next phases of the Heraklion tsunami hazard mitigation program. This is contribution to the EU-FP7 projects ZIP (Zooming In between Plates, grant no: 604713, 2013) and ASTARTE (Assessment, Strategy And Risk Reduction for Tsunamis in Europe), grant no: 603839, 2013.

Nitrogen concentrations in mosses indicate the spatial distribution of atmospheric nitrogen deposition in Europe

Energy Technology Data Exchange (ETDEWEB)

Harmens, H., E-mail: hh@ceh.ac.uk [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Norris, D.A., E-mail: danor@ceh.ac.uk [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Cooper, D.M., E-mail: cooper@ceh.ac.uk [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Mills, G., E-mail: gmi@ceh.ac.uk [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Steinnes, E., E-mail: Eiliv.Steinnes@chem.ntnu.no [Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim (Norway); Kubin, E., E-mail: Eero.Kubin@metla.fi [Finnish Forest Research Institute, Kirkkosaarentie 7, 91500 Muhos (Finland); Thoeni, L., E-mail: lotti.thoeni@fub-ag.ch [FUB-Research Group for Environmental Monitoring, Alte Jonastrasse 83, 8640 Rapperswil (Switzerland); Aboal, J.R., E-mail: jesusramon.aboal@usc.es [University of Santiago de Compostela, Faculty of Biology, Department of Ecology, 15782 Santiago de Compostela (Spain); Alber, R., E-mail: Renate.Alber@provinz.bz.it [Environmental Agency of Bolzano, 39055 Laives (Italy); Carballeira, A., E-mail: alejo.carballeira@usc.es [University of Santiago de Compostela, Faculty of Biology, Department of Ecology, 15782 Santiago de Compostela (Spain); Coskun, M., E-mail: coskunafm@yahoo.com [Canakkale Onsekiz Mart University, Faculty of Medicine, Department of Medical Biology, 17100 Canakkale (Turkey); De Temmerman, L., E-mail: ludet@var.fgov.be [Veterinary and Agrochemical Research Centre, Tervuren (Belgium); Frolova, M., E-mail: marina.frolova@lvgma.gov.lv [Latvian Environment, Geology and Meteorology Agency, Riga (Latvia); Gonzalez-Miqueo, L., E-mail: lgonzale2@alumni.unav.es [Univ. of Navarra, Irunlarrea No 1, 31008 Pamplona (Spain)

2011-10-15

In 2005/6, nearly 3000 moss samples from (semi-)natural location across 16 European countries were collected for nitrogen analysis. The lowest total nitrogen concentrations in mosses (<0.8%) were observed in northern Finland and northern UK. The highest concentrations ({>=}1.6%) were found in parts of Belgium, France, Germany, Slovakia, Slovenia and Bulgaria. The asymptotic relationship between the nitrogen concentrations in mosses and EMEP modelled nitrogen deposition (averaged per 50 km x 50 km grid) across Europe showed less scatter when there were at least five moss sampling sites per grid. Factors potentially contributing to the scatter are discussed. In Switzerland, a strong (r{sup 2} = 0.91) linear relationship was found between the total nitrogen concentration in mosses and measured site-specific bulk nitrogen deposition rates. The total nitrogen concentrations in mosses complement deposition measurements, helping to identify areas in Europe at risk from high nitrogen deposition at a high spatial resolution. - Highlights: > Nitrogen concentrations in mosses were determined at ca. 3000 sites across Europe. > Moss concentrations were compared with EMEP modelled nitrogen deposition. > The asymptotic relationship for Europe showed saturation at ca. 15 kg N ha{sup -1} y{sup -1}. > Linear relationships were found with measured nitrogen deposition in some countries. > Moss concentrations complement deposition measurements at high spatial resolution. - Mosses as biomonitors of atmospheric nitrogen deposition in Europe.

Nitrogen solubility in the deep mantle and the origin of Earth's primordial nitrogen budget

Science.gov (United States)

Yoshioka, Takahiro; Wiedenbeck, Michael; Shcheka, Svyatoslav; Keppler, Hans

2018-04-01

The solubility of nitrogen in the major minerals of the Earth's transition zone and lower mantle (wadsleyite, ringwoodite, bridgmanite, and Ca-silicate perovskite) coexisting with a reduced, nitrogen-rich fluid phase was measured. Experiments were carried out in multi-anvil presses at 14 to 24 GPa and 1100 to 1800 °C close to the Fe-FeO buffer. Starting materials were enriched in 15N and the nitrogen concentrations in run products were measured by secondary ion mass spectrometry. Observed nitrogen (15N) solubilities in wadsleyite and ringwoodite typically range from 10 to 250 μg/g and strongly increase with temperature. Nitrogen solubility in bridgmanite is about 20 μg/g, while Ca-silicate perovskite incorporates about 30 μg/g under comparable conditions. Partition coefficients of nitrogen derived from coexisting phases are DNwadsleyite/olivine = 5.1 ± 2.1, DNringwoodite/wadsleyite = 0.49 ± 0.29, and DNbridgmanite/ringwoodite = 0.24 (+ 0.30 / - 0.19). Nitrogen solubility in the solid, iron-rich metal phase coexisting with the silicates was also measured and reached a maximum of nearly 1 wt.% 15N at 23 GPa and 1400 °C. These data yield a partition coefficient of nitrogen between iron metal and bridgmanite of DNmetal/bridgmanite ∼ 98, implying that in a lower mantle containing about 1% of iron metal, about half of the nitrogen still resides in the silicates. The high nitrogen solubility in wadsleyite and ringwoodite may be responsible for the low nitrogen concentrations often observed in ultradeep diamonds from the transition zone. Overall, the solubility data suggest that the transition zone and the lower mantle have the capacity to store at least 33 times the mass of nitrogen presently residing in the atmosphere. By combining the nitrogen solubility data in minerals with data on nitrogen solubility in silicate melts, mineral/melt partition coefficients of nitrogen can be estimated, from which the behavior of nitrogen during magma ocean crystallization can

Effect of residual nitrogen and fertilizer nitrogen on sugar beet production in Finland

Directory of Open Access Journals (Sweden)

Veikko Brummer

1974-09-01

Full Text Available Preliminary determinations for NO3- and NH4-N in topsoil from nitrogen field experiments are discussed. The amounts of residual nitrogen as well as the dates and depth for sampling are considerd in order to investigate the need of fertilizer-N for continuous sugar beet. Tops ploughed down as manure increased the available soil nitrogen by about 50 kg/ha. In practice nitrogen from fertilizer and farmyard manure given to previous beet crops seems to accumulate in the beet soils of Finland. The concentrations of nitrate and ammonium nitrogen in topsoil were low in the spring of 1972 and 1973. NO3-N increased in topsoil during the early summer, and the highest concentrations were found at the beginning of July. Starting from the middle of July the amount of NH4-N began to increase both in topsoil and in subsoil. With increasing amounts of nitrogen in the topsoil the sugar content decreases continuously. Also the α-amio N content of beets correlates with the soil nitrogen. There is experimental evidence that 150 180 kg/ha nitrate nitrogen in topsoil (residual + fertilizer N in early July gives the best economic result. The effects of fertilizer and accumulated soil nitrogen on the sugar beet quality together with som other experimental data have been statistically analysed. Regression coefficients indicated that both forms of nitrogen affected the suger content, the α-amino N concentration and clear juice purity, in a similar way.

Is nitrogen the next carbon?

Science.gov (United States)

Battye, William; Aneja, Viney P.; Schlesinger, William H.

2017-09-01

Just as carbon fueled the Industrial Revolution, nitrogen has fueled an Agricultural Revolution. The use of synthetic nitrogen fertilizers and the cultivation of nitrogen-fixing crops both expanded exponentially during the last century, with most of the increase occurring after 1960. As a result, the current flux of reactive, or fixed, nitrogen compounds to the biosphere due to human activities is roughly equivalent to the total flux of fixed nitrogen from all natural sources, both on land masses and in the world's oceans. Natural fluxes of fixed nitrogen are subject to very large uncertainties, but anthropogenic production of reactive nitrogen has increased almost fivefold in the last 60 years, and this rapid increase in anthropogenic fixed nitrogen has removed any uncertainty on the relative importance of anthropogenic fluxes to the natural budget. The increased use of nitrogen has been critical for increased crop yields and protein production needed to keep pace with the growing world population. However, similar to carbon, the release of fixed nitrogen into the natural environment is linked to adverse consequences at local, regional, and global scales. Anthropogenic contributions of fixed nitrogen continue to grow relative to the natural budget, with uncertain consequences.

Nitrogen accumulation and residual effects of nitrogen catch crops

DEFF Research Database (Denmark)

Jensen, E.S.

1991-01-01

The nitrogen accumulation in Italian ryegrass (Lolium multiflorum Lam.), perennial ryegrass (Lolium perenne L.), white mustard (Sinapis alba L.) and tansy phacelia (Phacelia tanacetifolia L.), under- or aftersown as nitrogen catch crops to spring barley (Hordeum vulgare L.) and field pea (Pisum s...

Relationship of Nitrogen Use Efficiency with the Activities of Enzymes Involved in Nitrogen Uptake and Assimilation of Finger Millet Genotypes Grown under Different Nitrogen Inputs

Directory of Open Access Journals (Sweden)

Nidhi Gupta

2012-01-01

Full Text Available Nitrogen responsiveness of three-finger millet genotypes (differing in their seed coat colour PRM-1 (brown, PRM-701 (golden, and PRM-801 (white grown under different nitrogen doses was determined by analyzing the growth, yield parameters and activities of nitrate reductase (NR, glutamine synthetase (GS, glutamate synthase; GOGAT, and glutamate dehydrogenase (GDH at different developmental stages. High nitrogen use efficiency and nitrogen utilization efficiency were observed in PRM-1 genotype, whereas high nitrogen uptake efficiency was observed in PRM-801 genotype. At grain filling nitrogen uptake efficiency in PRM-1 negatively correlated with NR, GS, GOGAT activities whereas it was positively correlated in PRM-701 and PRM-801, however, GDH showed a negative correlation. Growth and yield parameters indicated that PRM-1 responds well at high nitrogen conditions while PRM-701 and PRM-801 respond well at normal and low nitrogen conditions respectively. The study indicates that PRM-1 is high nitrogen responsive and has high nitrogen use efficiency, whereas golden PRM-701 and white PRM-801 are low nitrogen responsive genotypes and have low nitrogen use efficiency. However, the crude grain protein content was higher in PRM-801 genotype followed by PRM-701 and PRM-1, indicating negative correlation of nitrogen use efficiency with source to sink relationship in terms of seed protein content.

Glutamine nitrogen and ammonium nitrogen supplied as a nitrogen source is not converted into nitrate nitrogen of plant tissues of hydroponically grown pak-choi (Brassica chinensis L.).

Science.gov (United States)

Wang, H-J; Wu, L-H; Tao, Q-N; Miller, D D; Welch, R M

2009-03-01

Many vegetables, especially leafy vegetables, accumulate NO(-) (3)-N in their edible portions. High nitrate levels in vegetables constitute a health hazard, such as cancers and blue baby syndrome. The aim of this study was to determine if (1) ammonium nitrogen (NH(+) (4)-N) and glutamine-nitrogen (Gln-N) absorbed by plant roots is converted into nitrate-nitrogen of pak-choi (Brassica chinensis L.) tissues, and (2) if nitrate-nitrogen (NO(-) (3)-N) accumulation and concentration of pak-choi tissues linearly increase with increasing NO(-) (3)-N supply when grown in nutrient solution. In experiment 1, 4 different nitrogen treatments (no nitrogen, NH(+) (4)-N, Gln-N, and NO(-) (3)-N) with equal total N concentrations in treatments with added N were applied under sterile nutrient medium culture conditions. In experiment 2, 5 concentrations of N (from 0 to 48 mM), supplied as NO(-) (3)-N in the nutrient solution, were tested. The results showed that Gln-N and NH(+) (4)-N added to the nutrient media were not converted into nitrate-nitrogen of plant tissues. Also, NO(-) (3)-N accumulation in the pak-choi tissues was the highest when plants were supplied 24 mM NO(-) (3)-N in the media. The NO(-) (3)-N concentration in plant tissues was quadratically correlated to the NO(-) (3)-N concentration supplied in the nutrient solution.

The nitrogen cycle: Atmosphere interactions

Science.gov (United States)

Levine, J. S.

1984-01-01

Atmospheric interactions involving the nitrogen species are varied and complex. These interactions include photochemical reactions, initiated by the absorption of solar photons and chemical kinetic reactions, which involve both homogeneous (gas-to-gas reactions) and heterogeneous (gas-to-particle) reactions. Another important atmospheric interaction is the production of nitrogen oxides by atmospheric lightning. The nitrogen cycle strongly couples the biosphere and atmosphere. Many nitrogen species are produced by biogenic processes. Once in the atmosphere nitrogen oxides are photochemically and chemically transformed to nitrates, which are returned to the biosphere via precipitation, dry deposition and aerosols to close the biosphere-atmosphere nitrogen cycle. The sources, sinks and photochemistry/chemistry of the nitrogen species; atmospheric nitrogen species; souces and sinks of nitrous oxide; sources; sinks and photochemistry/chemistry of ammonia; seasonal variation of the vertical distribution of ammonia in the troposphere; surface and atmospheric sources of the nitrogen species, and seasonal variation of ground level ammonia are summarized.

[Effects of water deficit and nitrogen fertilization on winter wheat growth and nitrogen uptake].

Science.gov (United States)

Qi, You-Ling; Zhang, Fu-Cang; Li, Kai-Feng

2009-10-01

Winter wheat plants were cultured in vitro tubes to study their growth and nitrogen uptake under effects of water deficit at different growth stages and nitrogen fertilization. Water deficit at any growth stages could obviously affect the plant height, leaf area, dry matter accumulation, and nitrogen uptake. Jointing stage was the most sensitive stage of winter wheat growth to water deficit, followed by flowering stage, grain-filling stage, and seedling stages. Rewatering after the water deficit at seedling stage had a significant compensation effect on winter wheat growth, and definite compensation effect was observed on the biomass accumulation and nitrogen absorption when rewatering was made after the water deficit at flowering stage. Under the same nitrogen fertilization levels, the nitrogen accumulation in root with water deficit at seedling, jointing, flowering, and grain-filling stages was reduced by 25.82%, 55.68%, 46.14%, and 16.34%, and the nitrogen accumulation in aboveground part was reduced by 33.37%, 51.71%, 27.01%, and 2.60%, respectively, compared with no water deficit. Under the same water deficit stages, the nitrogen content and accumulation of winter wheat decreased with decreasing nitrogen fertilization level, i. e., 0.3 g N x kg(-1) FM > 0.2 g N x kg(-1) FM > 0.1 g N x kg(-1) FM. Nitrogen fertilization had obvious regulation effect on winter wheat plant growth, dry matter accumulation, and nitrogen uptake under water stress.

Modelling nutrient cycling in forest ecosystems; Modellering av naeringssyklus i skogoekosystemer

Energy Technology Data Exchange (ETDEWEB)

Kvindesland, Sheila H.S.B.

1997-12-31

Acid deposition`s threat to fresh water and forest environments became an issue in the late 1960s. Acid deposition and forest nutrient cycling then began to be researched in greater co-operation. This thesis studies nutrient cycling processes in Norway spruce forests, emphasizing the effects on soil chemical properties, soil solution chemistry and streamwater chemistry. It investigates the effects of different aged stands on nutrient cycling and sets up nutrient budgets of the base cations and nitrogen at two sites in Norway. It also selects, documents, calibrates, tests and improves nutrient cycling models for use in Norwegian forests. 84 refs., 44 figs., 46 tabs.

Dissolved organic nitrogen recalcitrance and bioavailable nitrogen quantification for effluents from advanced nitrogen removal wastewater treatment facilities.

Science.gov (United States)

Fan, Lu; Brett, Michael T; Jiang, Wenju; Li, Bo

2017-10-01

The objective of this study was to determine the composition of nitrogen (N) in the effluents of advanced N removal (ANR) wastewater treatment plants (WWTPs). This study also tested two different experimental protocols for determining dissolved N recalcitrance. An analysis of 15 effluent samples from five WWTPs, showed effluent concentrations and especially effluent composition varied greatly from one system to the other, with total nitrogen (TN) ranging between 1.05 and 8.10 mg L -1 . Nitrate (NO 3 - ) accounted for between 38 ± 32% of TN, and ammonium accounted for a further 29 ± 28%. All of these samples were dominated by dissolved inorganic nitrogen (DIN; NO 3 -  + NH 4 + ), and uptake experiments indicated the DIN fraction was as expected highly bioavailable. Dissolved organic N (DON) accounted for 20 ± 11% for the total dissolved N in these effluents, and uptake experiments indicated the bioavailability of this fraction varied between 27 ± 26% depending on the WWTP assessed. These results indicate near complete DIN removal should be the primary goal of ANR treatment systems. The comparison of bioavailable nitrogen (BAN) quantification protocols showed that the dissolved nitrogen uptake bioassay approach was clearly a more reliable way to determine BAN concentrations compared to the conventional cell yield protocol. Moreover, because the nitrogen uptake experiment was much more sensitive, this protocol made it easier to detect extrinsic factors (such as biological contamination or toxicity) that could affect the accuracy of these bioassays. Based on these results, we recommend the nitrogen uptake bioassay using filtered and autoclaved samples to quantify BAN concentrations. However, for effluent samples indicating toxicity, algal bioassays will not accurately quantify BAN. Copyright © 2017 Elsevier Ltd. All rights reserved.

Determination of nitrogen absorption and endogenous nitrogen secretion in the digestive tract of pigs fed with nitrogen-15-labelled dried whey

International Nuclear Information System (INIS)

Gebhardt, G.; Souffrant, W.; Koehler, R.; Zebrowska, T.

1977-01-01

Two fistulated pigs weighing between 15kg and 54kg were given experimental diets containing 15 N-labelled dried whey. The labelled experimental diets were given once only. Samples of the digesta were taken from the duodenum and terminal ileum at various intervals of time up to 48h after feeding the labelled protein feed. The digesta were separated into the four following fractions: Residue on centrifugation, proteins, peptides and free amino acids. The secretion of endogenous nitrogen in the duodenum was 12.5g/24h in pigs having a live weight of 50kg. The endogenous nitrogen was found to be relatively uniformly distributed among the four fractions. The rate of secretion of endogenous nitrogen showed a continuous decrease during 24h. The secretion of endogenous nitrogen in the terminal ileum was 54 to 60mg of nitrogen per kilogram live weight. After passage through the small intestine the greater part of the free amino acids in digesta was of exogenous origin. In the protein fraction most came from endogenous proteins. A true absorption of 17% of nitrogen was determined in the duodenum. The amount of nitrogen absorbed in the terminal part of the small intestine was, on average, 90% relative to the nitrogen intake. The true digestibility calculated with the amount of 15 N in food and faeces was 98%. (author)

Effects of Controlled-Release Urea on Grain Yield of Spring Maize, Nitrogen Use Efficiency and Nitrogen Balance

Directory of Open Access Journals (Sweden)

JI Jing-hong

2017-03-01

Full Text Available The effects of mixing controlled-released urea (CRU (release period of resin coated urea is 90 days and urea (U on maize yield, nitrogen use efficiency and nitrogen balance were studied by 4 plot experiments (site:Shuangcheng, Binxian, Harbin and Zhaoyuan in two years (from year 2011 to 2012 to clarify the effect of controlled release urea on spring maize and soil nitrogen balance. Results were as follow:Spring maize yield and nitrogen absorption were increased with the increasing nitrogen fertilizer. Compared with applying urea treatment, applying CRU could increase yield, nitrogen absorption, nitrogen use efficiency, agriculture efficiency of nitrogen and nitrogen contribution rate. Under the same amount of nitrogen (100%, 75%, 50%, compared with 100% U as basic fertilizer treatment, maize yield of 100% CRU treatment increased 391, 427, 291 kg·hm-2, nitrogen use efficiency increased by 5.9%,4.9% and 5.1%, agriculture efficiency of nitrogen increased 2.0, 2.6, 2.6 kg·kg-1, and nitrogen contribution rate increased 2.7%, 3.1% and 2.4%, respectively. The value of maize yield, nitrogen absorption, nitrogen use efficiency and agriculture efficiency of nitrogen between the treatment four (40% urea as basic fertilizer+60% urea as topdressing and treatment five (40% urea plus 60% controlled release urea as basic fertilizer were similar. Apparent profit and loss of nitrogen decreased with the increase of nitrogen nitrogen fertilizer. Nitrogen apparent loss by applying 100% controlled release urea was reduced of 15.0 kg·hm-2 than applying 100% U treatment;Nitrogen apparent loss amount was decreased of 23.9 kg·hm-2 under treatment five. The method of mixing 40% urea and 60% controlled release urea should be applied in maize production in Heilongjiang Province.

Effect of organic manure on nitrogen mineralization, nitrogen accumulation, nitrogen use efficiency and apparent nitrogen recovery of cauliflower (Braccica oleracea L., var. Botrytis)

NARCIS (Netherlands)

Beah, A.A.; Norman, P.E.; Scholberg, J.M.S.; Lantinga, E.A.; Conteh, A.R.

2015-01-01

Aims: The main aim of the study was to assess the effects of organic manure on nitrogen mineralization, uptake, use and recovery of cauliflower.
Methodology: Nitrogen is one of the major yield limiting nutrients in cauliflower production. However, organic manure is applied to supplement soil

Lap time simulation and design optimisation of a brushed DC electric motorcycle for the Isle of Man TT Zero Challenge

Science.gov (United States)

Dal Bianco, N.; Lot, R.; Matthys, K.

2018-01-01

This works regards the design of an electric motorcycle for the annual Isle of Man TT Zero Challenge. Optimal control theory was used to perform lap time simulation and design optimisation. A bespoked model was developed, featuring 3D road topology, vehicle dynamics and electric power train, composed of a lithium battery pack, brushed DC motors and motor controller. The model runs simulations over the entire ? or ? of the Snaefell Mountain Course. The work is validated using experimental data from the BX chassis of the Brunel Racing team, which ran during the 2009 to 2015 TT Zero races. Optimal control is used to improve drive train and power train configurations. Findings demonstrate computational efficiency, good lap time prediction and design optimisation potential, achieving a 2 minutes reduction of the reference lap time through changes in final drive gear ratio, battery pack size and motor configuration.

Exhaustive Conversion of Inorganic Nitrogen to Nitrogen Gas Based on a Photoelectro-Chlorine Cycle Reaction and a Highly Selective Nitrogen Gas Generation Cathode.

Science.gov (United States)

Zhang, Yan; Li, Jinhua; Bai, Jing; Shen, Zhaoxi; Li, Linsen; Xia, Ligang; Chen, Shuai; Zhou, Baoxue

2018-02-06

A novel method for the exhaustive conversion of inorganic nitrogen to nitrogen gas is proposed in this paper. The key properties of the system design included an exhaustive photoelectrochemical cycle reaction in the presence of Cl - , in which Cl· generated from oxidation of Cl - by photoholes selectively converted NH 4 + to nitrogen gas and some NO 3 - or NO 2 - . The NO 3 - or NO 2 - was finally reduced to nitrogen gas on a highly selective Pd-Cu-modified Ni foam (Pd-Cu/NF) cathode to achieve exhaustive conversion of inorganic nitrogen to nitrogen gas. The results indicated total nitrogen removal efficiencies of 30 mg L -1 inorganic nitrogen (NO 3 - , NH 4 + , NO 3 - /NH 4 + = 1:1 and NO 2 - /NO 3 - /NH 4 + = 1:1:1) in 90 min were 98.2%, 97.4%, 93.1%, and 98.4%, respectively, and the remaining nitrogen was completely removed by prolonging the reaction time. The rapid reduction of nitrate was ascribed to the capacitor characteristics of Pd-Cu/NF that promoted nitrate adsorption in the presence of an electric double layer, eliminating repulsion between the cathode and the anion. Nitrate was effectively removed with a rate constant of 0.050 min -1 , which was 33 times larger than that of Pt cathode. This system shows great potential for inorganic nitrogen treatment due to the high rate, low cost, and clean energy source.

Nitrogen Dynamics in European Forest Ecosystems: Considerations regarding Anthropogenic Nitrogen Depositions

OpenAIRE

Agren, G.I.; Kauppi, P.

1983-01-01

This study deals with the nutrient cycle of forest ecosystems over large geographic regions in Europe as affected by nitrogen deposition. The view is taken that the nitrogen cycle of a forest ecosystem has a maximum capacity for circulating nitrogen. Two different cases are defined: case (1) in which the nutrient cycle functions below its maximum capacity, and case (2) in which the circulation operates at the maximum level.

Nitrogen in Chinese coals

Science.gov (United States)

Wu, D.; Lei, J.; Zheng, B.; Tang, X.; Wang, M.; Hu, Jiawen; Li, S.; Wang, B.; Finkelman, R.B.

2011-01-01

Three hundred and six coal samples were taken from main coal mines of twenty-six provinces, autonomous regions, and municipalities in China, according to the resource distribution and coal-forming periods as well as the coal ranks and coal yields. Nitrogen was determined by using the Kjeldahl method at U. S. Geological Survey (USGS), which exhibit a normal frequency distribution. The nitrogen contents of over 90% Chinese coal vary from 0.52% to 1.41% and the average nitrogen content is recommended to be 0.98%. Nitrogen in coal exists primarily in organic form. There is a slight positive relationship between nitrogen content and coal ranking. ?? 2011 Science Press, Institute of Geochemistry, CAS and Springer Berlin Heidelberg.

How exogenous nitric oxide regulates nitrogen assimilation in wheat seedlings under different nitrogen sources and levels.

Science.gov (United States)

Balotf, Sadegh; Islam, Shahidul; Kavoosi, Gholamreza; Kholdebarin, Bahman; Juhasz, Angela; Ma, Wujun

2018-01-01

Nitrogen (N) is one of the most important nutrients for plants and nitric oxide (NO) as a signaling plant growth regulator involved in nitrogen assimilation. Understanding the influence of exogenous NO on nitrogen metabolism at the gene expression and enzyme activity levels under different sources of nitrogen is vitally important for increasing nitrogen use efficiency (NUE). This study investigated the expression of key genes and enzymes in relation to nitrogen assimilation in two Australian wheat cultivars, a popular high NUE cv. Spitfire and a normal NUE cv. Westonia, under different combinations of nitrogen and sodium nitroprusside (SNP) as the NO donor. Application of NO increased the gene expressions and activities of nitrogen assimilation pathway enzymes in both cultivars at low levels of nitrogen. At high nitrogen supplies, the expressions and activities of N assimilation genes increased in response to exogenous NO only in cv. Spitfire but not in cv. Westonia. Exogenous NO caused an increase in leaf NO content at low N supplies in both cultivars, while under high nitrogen treatments, cv. Spitfire showed an increase under ammonium nitrate (NH4NO3) treatment but cv. Westonia was not affected. N assimilation gene expression and enzyme activity showed a clear relationship between exogenous NO, N concentration and N forms in primary plant nitrogen assimilation. Results reveal the possible role of NO and different nitrogen sources on nitrogen assimilation in Triticum aestivum plants.

Late Pleistocene Stratigraphy and Palaeobotany of the Isles of Scilly

Science.gov (United States)

Scourse, J. D.

1991-12-01

A re-evaluation of the Pleistocene stratigraphy of the Isles of Scilly has enabled the formal definition of eight lithostratigraphic units of member status grouped into two formations. A chronology of events has been provided by radiocarbon (14C) determinations, optical and thermoluminescene (TL) dates. Intersite correlations have been strengthened by palynology, which has aided palaeoenvironmental reconstruction. The defined units have been incorporated into two lithostratigraphic models, one for the `northern' (glacial) Scillies and one for the `southern' (extra-glacial) Scillies. Raised beach sediments of the Watermill Sands and Gravel in the southern Scillies are overlain by the Porthloo Breccia, a unit of soliflucted material derived exclusively from the weathering of local granite. Organic sequences at Carn Morval, Watermill Cove, Porth Askin, Porth Seal and Bread and Cheese Cove occur within the Porthloo Breccia, and are interpreted as the infillings of ponds associated with active solifluction. Radiocarbon determinations from these organic sediments are critical because they pre-date units associated with a glacial event. The 14C determinations indicate deposition of the organic material between 34500-800+885 (Q-2410) and 21500-800+890 (Q-2358) years BP and provide a maximum age for the glacial event and the first radiometric dates for the coastal `head' sediments of southwest England. The pollen assemblages from these organic sites all record open grassland vegetation, and represent the earliest vegetational record for the Scillies. High Pinus values are interpreted as evidence of climatic deterioration. In the southern Scillies, the Porthloo Breccia is overlain by the Old Man Sandloess, a coarse aeolian silt with subdominant fine sand, TL-dated to 18600-3700+3700 years (QTL-ld and lf; Wintle 1981) and optically dated to 20000-7000+7000 and 26000-9000+10000 years (two samples; 738al and 741al; Smith et al. 1990). This material occurs in a variety of facies

[Nitrogen Fraction Distributions and Impacts on Soil Nitrogen Mineralization in Different Vegetation Restorations of Karst Rocky Desertification].

Science.gov (United States)

Hu, Ning; Ma, Zhi-min; Lan, Jia-cheng; Wu, Yu-chun; Chen, Gao-qi; Fu, Wa-li; Wen, Zhi-lin; Wang, Wen-jing

2015-09-01

In order to illuminate the impact on soil nitrogen accumulation and supply in karst rocky desertification area, the distribution characteristics of soil nitrogen pool for each class of soil aggregates and the relationship between aggregates nitrogen pool and soil nitrogen mineralization were analyzed in this study. The results showed that the content of total nitrogen, light fraction nitrogen, available nitrogen and mineral nitrogen in soil aggregates had an increasing tendency along with the descending of aggregate-size, and the highest content was occurred in 5mm and 2-5 mm classes, and the others were the smallest. With the positive vegetation succession, the weight percentage of > 5 mm aggregate-size classes was improved and the nitrogen storage of macro-aggregates also was increased. Accordingly, the capacity of soil supply mineral nitrogen and storage organic nitrogen were intensified.

The nitrogen footprint tool network: a multi-institution program to reduce nitrogen pollution

Science.gov (United States)

Anthropogenic sources of reactive nitrogen have local and global impacts on air and water quality and detrimental effects on human and ecosystem health. This paper uses the nitrogen footprint tool (NFT) to determine the amount of nitrogen (N) released as a result of institutional...

Determination of nitrogen in boron carbide with the Leco UO-14 Nitrogen Determinator

International Nuclear Information System (INIS)

Gardner, R.D.; Ashley, W.H.; Henicksman, A.L.

1977-11-01

Use of various metals as fluxes for releasing nitrogen from boron carbide in the Leco Nitrogen Determinator was investigated. Metals such as iron, chromium, and molybdenum that wet the graphite crucible all promoted nitrogen release. Tin, copper, aluminum, and platinum did not wet the graphite and were of no value as fluxes. A procedure for sample handling and the resulting performance of the method are described. The precision at 0.06 to 0.6 percent nitrogen averaged 4 percent relative standard deviation

Transformation of fertilizer nitrogen in soil

International Nuclear Information System (INIS)

Soechting, H.

1980-01-01

Pot experiments are described in which the transformations between nitrogen added as fertilizer urea, plant-assimilated nitrogen, and different chemical fractions of soil or added straw nitrogen were studied with 15 N as a tracer. The data indicated that: (a) The transformation of added fertilizer nitrogen to immobilized amide nitrogen is decreased with added decomposable organic carbon. The transformation to immobilized α-amino N is increased, on the other hand, by the addition of decomposable organic carbon. (b) The freshly immobilized amide nitrogen is more readily remineralized than the α-amino form. The immobilization of added nitrogen continues in the presence of growing plants. (c) Mineralization of nitrogen added as 15 N-labelled straw is also increased with increasing fertilizer-nitrogen additions. (author)

Changes in the content of total nitrogen and mineral nitrogen in the basil herb depending on the cultivar and nitrogen nutrition

Directory of Open Access Journals (Sweden)

Katarzyna Dzida

2013-04-01

Full Text Available Among fundamental nutrients, nitrogen fertilization is considered one of the most effective factors affecting both the yield and the quality of plant material. Nitrogen form used for fertilizing is also of great importance. The aim of this study was to investigate the impact of nitrogen nutrition (calcium nitrate, ammonium nitrate, and urea as well as (green, purple, and‘Fino Verde’ on the chemical composition and yielding of basil (Ocimum basilicumL.. After drying the plant material at a temperature of 60°C and milling, total nitrogen was determined by means of Kjeldahl method, while mineral nitrogen content (N-NH 4, N-NO 3 was analyzed in 2% acetic acid extract. Yield of fresh basil matter depended significantly on the variety grown. The highest yields were obtained from a cultivar of ‘Fino Verde’ fertilized with ammonium nitrate. The purple variety plants fertilized with urea were characterized by a largest amount of total nitrogen. The‘Fino Verde’cultivar fertilized with urea accumulated the least quantities of nitrates in the basil herb.

Role of chemistry in uranium leaching from sand stone ore bodies by ISL technique (abstract)

International Nuclear Information System (INIS)

Sheikh, A.K.; Hanif, M.

2011-01-01

The importance of uranium for nuclear power generation is increasing day by day in the current energy requirement scenario. The energy sector is reverting to nuclear power generation in many countries. Keeping in view the limited availability of fossil fuels and the problems associated with its exploration. In situ leach mining of uranium is currently employed in many countries for extraction of uranium in soft rocks from subsurface where deposits are lying deeper and the cost of underground mining (UGM) are high. In situ leaching of uranium revolves around injection of leachant (usually bicarbonate) and oxidant into the host rock without disturbing the strata thereby solubilizing the uranium in solution form. The resultant leach is then pumped out and sent to processing plant for production of yellow cake. The Chemistry Division NMC-I, D. G. Khan plays a vital role in ISL Mining of uranium, starting from initial exploration of ore body, analysis of leach liquor and other liquid samples up to the final step of yellow cake formation. During all these analysis to ensure Quality control, Chemistry Division utilizes modern / updated analytical techniques e.g. Atomic Absorption Spectroscopy, Spectrophotometry, Fluorimetry and Potentiometry. R and D studies are also being carried out to optimize and economize the operational parameters accordingly. This presentation basically encompasses the role of Chemistry at various levels and stages at Mining Projects to achieve this goal. (author)

Eighth international congress on nitrogen fixation

Energy Technology Data Exchange (ETDEWEB)

1990-01-01

This volume contains the proceedings of the Eighth International Congress on Nitrogen Fixation held May 20--26, 1990 in Knoxville, Tennessee. The volume contains abstracts of individual presentations. Sessions were entitled Recent Advances in the Chemistry of Nitrogen Fixation, Plant-microbe Interactions, Limiting Factors of Nitrogen Fixation, Nitrogen Fixation and the Environment, Bacterial Systems, Nitrogen Fixation in Agriculture and Industry, Plant Function, and Nitrogen Fixation and Evolution.

Mineral commodity profiles: nitrogen

Science.gov (United States)

Kramer, Deborah A.

2004-01-01

Overview -- Nitrogen (N) is an essential element of life and a part of all animal and plant proteins. As a part of the DNA and RNA molecules, nitrogen is an essential constituent of each individual's genetic blueprint. As an essential element in the chlorophyll molecule, nitrogen is vital to a plant's ability to photosynthesize. Some crop plants, such as alfalfa, peas, peanuts, and soybeans, can convert atmospheric nitrogen into a usable form by a process referred to as 'fixation.' Most of the nitrogen that is available for crop production, however, comes from decomposing animal and plant waste or from commercially produced fertilizers. Commercial fertilizers contain nitrogen in the form of ammonium and/or nitrate or in a form that is quickly converted to the ammonium or nitrate form once the fertilizer is applied to the soil. Ammonia is generally the source of nitrogen in fertilizers. Anhydrous ammonia is commercially produced by reacting nitrogen with hydrogen under high temperatures and pressures. The source of nitrogen is the atmosphere, which is almost 80 percent nitrogen. Hydrogen is derived from a variety of raw materials, which include water, and crude oil, coal, and natural gas hydrocarbons. Nitrogen-based fertilizers are produced from ammonia feedstocks through a variety of chemical processes. Small quantities of nitrates are produced from mineral resources principally in Chile. In 2002, anhydrous ammonia and other nitrogen materials were produced in more than 70 countries. Global ammonia production was 108 million metric tons (Mt) of contained nitrogen. With 28 percent of this total, China was the largest producer of ammonia. Asia contributed 46 percent of total world ammonia production, and countries of the former U.S.S.R. represented 13 percent. North America also produced 13 percent of the total; Western Europe, 9 percent; the Middle East, 7 percent; Central America and South America, 5 percent; Eastern Europe, 3 percent; and Africa and Oceania

Bacterial nitrogen fixation in sand bioreactors treating winery wastewater with a high carbon to nitrogen ratio.

Science.gov (United States)

Welz, Pamela J; Ramond, Jean-Baptiste; Braun, Lorenz; Vikram, Surendra; Le Roes-Hill, Marilize

2018-02-01

Heterotrophic bacteria proliferate in organic-rich environments and systems containing sufficient essential nutrients. Nitrogen, phosphorus and potassium are the nutrients required in the highest concentrations. The ratio of carbon to nitrogen is an important consideration for wastewater bioremediation because insufficient nitrogen may result in decreased treatment efficiency. It has been shown that during the treatment of effluent from the pulp and paper industry, bacterial nitrogen fixation can supplement the nitrogen requirements of suspended growth systems. This study was conducted using physicochemical analyses and culture-dependent and -independent techniques to ascertain whether nitrogen-fixing bacteria were selected in biological sand filters used to treat synthetic winery wastewater with a high carbon to nitrogen ratio (193:1). The systems performed well, with the influent COD of 1351 mg/L being reduced by 84-89%. It was shown that the nitrogen fixing bacterial population was influenced by the presence of synthetic winery effluent in the surface layers of the biological sand filters, but not in the deeper layers. It was hypothesised that this was due to the greater availability of atmospheric nitrogen at the surface. The numbers of culture-able nitrogen-fixing bacteria, including presumptive Azotobacter spp. exhibited 1-2 log increases at the surface. The results of this study confirm that nitrogen fixation is an important mechanism to be considered during treatment of high carbon to nitrogen wastewater. If biological treatment systems can be operated to stimulate this phenomenon, it may obviate the need for nitrogen addition. Copyright © 2017 Elsevier Ltd. All rights reserved.

Efficiency of nitrogen fertilizers for rice

OpenAIRE

Roger, Pierre-Armand; Grant, I.F.; Reddy, P.M.; Watanabe, I.

1987-01-01

The photosynthetic biomass that develops in the floodwater of wetland rice fields affects nitrogen dynamics in the ecosystem. This review summarizes available data on the nature, productivity, and composition of the photosynthetic aquatic biomass, and its major activities regarding the nitrogen cycle, i.e., nitrogen fixation by free living blue-green algae and #Azolla$, nitrogen trapping, nitrogen accumulation at the soil surface, its effect on nitrogen losses by ammonia volatilization, nitro...

Effect of different nitrogen application types on nitrogen utilization efficiency and fate of fertilizer for sugacane

International Nuclear Information System (INIS)

Wei Jianfeng; Wei Dongping; Liu Huanyu; Chen Chaojun; Lan Libin; Liang He

2013-01-01

A pot experiment in greenhouse was conducted with "1"5N-labeled urea 5 g/pot (equal to 450 kg · hm"-"2) total nitrogen by three kinds of treatments of disposable bottom application nitrogen before sowing (T1), 50% nitrogen before sowing and 50% nitrogrn during tillering stage (T2), and 30% nitrogen before sowing, 30% nitrogen during tillering stage and 40% nitrogen applied during elongation stage (T3) to investigate the use efficiency and fate of fertilizer nitrogen using the sugarcane cultivar ROC22. Results showed that almost 18% ∼ 29% of total N uptake by sugarcane was supplied by fertilizer, and 71% ∼ 82% N derived from soil and seed-stem. Nitrogen use efficiency ranged from 21.0% to 34.52%, with "1"5N-fertilizer residue of 37.61% ∼ 44.13%, and "1"5N-fertilizer loss of 21.35% ∼ 41.39% among three treatments. Under the three levels of nitrogen application, residual was "1"5N-fertilizer was mainly distributed in 0 ∼ 20 cm top soil. The uptake of nitrogen and the proportion of total N from fertilizer in sugarcane plant, the yield of stalk and sugar after the nitrogen applied, and the use efficiency and residue ratio of "1"5N-fertilizer increased significantly over time, while loss rate of "1"5N-fertilizer decreased significantly with a slight decline trend of nitrogen distribution and sucrose accumulation in stalk. The results also indicated that after the nitrogen applied the amounts "1"5N-fertilizer residue in 0 ∼ 20 cm top soil showed a rising trend, but dropped in 20 ∼ 40 cm soil profile. From the viewpoints of economic benefit and ecological benefit, the nitrogen fertilizer applied of T3 could be optimal treatment. (authors)

Nitrogen-doped carbon monolith for alkaline supercapacitors and understanding nitrogen-induced redox transitions.

Science.gov (United States)

Wang, Da-Wei; Li, Feng; Yin, Li-Chang; Lu, Xu; Chen, Zhi-Gang; Gentle, Ian R; Lu, Gao Qing; Cheng, Hui-Ming

2012-04-23

A nitrogen-doped porous carbon monolith was synthesized as a pseudo-capacitive electrode for use in alkaline supercapacitors. Ammonia-assisted carbonization was used to dope the surface with nitrogen heteroatoms in a way that replaced carbon atoms but kept the oxygen content constant. Ammonia treatment expanded the micropore size-distributions and increased the specific surface area from 383 m(2) g(-1) to 679 m(2) g(-1). The nitrogen-containing porous carbon material showed a higher capacitance (246 F g(-1)) in comparison with the nitrogen-free one (186 F g(-1)). Ex situ electrochemical spectroscopy was used to investigate the evolution of the nitrogen-containing functional groups on the surface of the N-doped carbon electrodes in a three-electrode cell. In addition, first-principles calculations were explored regarding the electronic structures of different nitrogen groups to determine their relative redox potentials. We proposed possible redox reaction pathways based on the calculated redox affinity of different groups and surface analysis, which involved the reversible attachment/detachment of hydroxy groups between pyridone and pyridine. The oxidation of nitrogen atoms in pyridine was also suggested as a possible reaction pathway. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Deposition of reactive nitrogen during the Rocky Mountain Airborne Nitrogen and Sulfur (RoMANS) study

International Nuclear Information System (INIS)

Beem, Katherine B.; Raja, Suresh; Schwandner, Florian M.; Taylor, Courtney; Lee, Taehyoung; Sullivan, Amy P.; Carrico, Christian M.; McMeeking, Gavin R.; Day, Derek; Levin, Ezra; Hand, Jenny; Kreidenweis, Sonia M.; Schichtel, Bret; Malm, William C.; Collett, Jeffrey L.

2010-01-01

Increases in reactive nitrogen deposition are a growing concern in the U.S. Rocky Mountain west. The Rocky Mountain Airborne Nitrogen and Sulfur (RoMANS) study was designed to improve understanding of the species and pathways that contribute to nitrogen deposition in Rocky Mountain National Park (RMNP). During two 5-week field campaigns in spring and summer of 2006, the largest contributor to reactive nitrogen deposition in RMNP was found to be wet deposition of ammonium (34% spring and summer), followed by wet deposition of nitrate (24% spring, 28% summer). The third and fourth most important reactive nitrogen deposition pathways were found to be wet deposition of organic nitrogen (17%, 12%) and dry deposition of ammonia (14%, 16%), neither of which is routinely measured by air quality/deposition networks operating in the region. Total reactive nitrogen deposition during the spring campaign was determined to be 0.45 kg ha -1 and more than doubled to 0.95 kg ha -1 during the summer campaign. - The reactive nitrogen deposition budget for Rocky Mountain National Park.

Terrestrial nitrogen cycles: Some unanswered questions

Science.gov (United States)

Vitousek, P.

1984-01-01

Nitrogen is generally considered to be the element which most often limits the growth of plants in both natural and agricultural ecosystems. It regulates plant growth because photosynthetic rates are strongly dependent on the concentration of nitrogen in leaves, and because relatively large mounts of protein are required for cell division and growth. Yet nitrogen is abundant in the biosphere - the well-mixed pool in the atmosphere is considered inexhaustible compared to biotic demand, and the amount of already fixed organic nitrogen in soils far exceeds annual plant uptake in terrestrial ecosystems. In regions where natural vegetation is not nitrogen limited, continuous cultivation induces nitrogen deficiency. Nitrogen loss from cultivated lands is more rapid than that of other elements, and nitrogen fertilization is generally required to maintain crop yield under any continuous system. The pervasiveness of nitrogen deficiency in many natural and most managed sites is discussed.

Competition and facilitation between unicellular nitrogen-fixing cyanobacteria and non-nitrogen-fixing phytoplankton species

NARCIS (Netherlands)

Agawin, N.S.; Rabouille, S.; Veldhuis, M.; Servatius, L.; Hol, S.; van Overzee, H.M.J.; Huisman, J.

2007-01-01

Abstract: Recent discoveries show that small unicellular nitrogen-fixing cyanobacteria are more widespread than previously thought and can make major contributions to the nitrogen budget of the oceans. We combined theory and experiments to investigate competition for nitrogen and light between these

Identification of genotypic variation for nitrogen response in potato (Solanum tuberosum) under low nitrogen input circumstances

NARCIS (Netherlands)

Tiemens-Hulscher, M.; Lammerts Van Bueren, E.; Struik, P.C.

2009-01-01

Nitrogen is an essential nutrient for crop growth. The demand for nitrogen in the potato crop is relatively high. However, in organic farming nitrogen input is rather limited, compared with conventional farming. In this research nine potato varieties were tested at three nitrogen levels. Genotypic

Emiliania Huxleyi (Prymnesiophyceae): Nitrogen-metabolism genes and their expression in response to external nitrogen souces

DEFF Research Database (Denmark)

Bruhn, Annette; LaRoche, Julie; Richardson, Katherine

2010-01-01

The availability and composition of dissolved nitrogen in ocean waters are factors that influence species composition in natural phytoplankton communities. The same factors affect the ratio of organic to inorganic carbon incorporation in calcifying species, such as the coccolithophore Emiliania...... huxleyi (Lohman) W. W. Hay et H. Mohler. E. huxleyi has been shown to thrive on various nitrogen sources, including dissolved organic nitrogen. Nevertheless, assimilation of dissolved nitrogen under nitrogen-replete and -limited conditions is not well understood in this ecologically important species....... In this study, the complete amino acid sequences for three functional genes involved in nitrogen metabolism in E. huxleyi were identified: a putative formamidase, a glutamine synthetase (GSII family), and assimilatory nitrate reductase. Expression patterns of the three enzymes in cells grown on inorganic...

Identification of genotypic variation for nitrogen response in potato (Solanum tuberosum) under low nitrogen input circumstances

OpenAIRE

Tiemens-Hulscher, M.; Lammerts Van Bueren, E.; Struik, P.C.

2009-01-01

Nitrogen is an essential nutrient for crop growth. The demand for nitrogen in the potato crop is relatively high. However, in organic farming nitrogen input is rather limited, compared with conventional farming. In this research nine potato varieties were tested at three nitrogen levels. Genotypic variation for yield, leaf area index, period of maximum soil cover, sensitivity for N-shortage and nitrogen efficiency under low input circumstances was found. However, in these experiments varietie...

Forest fuel reduces the nitrogen load

International Nuclear Information System (INIS)

Lundborg, A.

1993-03-01

A study of the literature was made on the basis of the following hypothesis: ''If nitrogen-rich felling residues are removed from the forest, the nitrogen load on the forest ecosystem is decreased and the risk of nitrogen saturation also decreases''. The study was designed to provide information on how the nitrogen situation is influenced if felling residues are removed from nitrogen-loaded forests and used as fuel. Felling residues release very little nitrogen during the first years after felling. They can immobilize nitrogen from the surroundings, make up a considerable addition to the nitrogen store in the soil, but also release nitrogen in later stages of degradation. The slash has an influence on the soil climate and thus on soil processes. Often there is an increase in the mineralization of litter and humus below the felling residues. At the same time, nitrification is favoured, particularly if the slash is left in heaps. Felling residues contain easily soluble nutrients that stimulate the metabolization of organic matter that otherwise is rather resistant to degradation. The slash also inhibits the clear-cut vegetation and its uptake of nitrogen. These effects result in increased leaching of nitrogen and minerals if the felling residues are left on the site. (99 refs.)

Demonstrating Paramagnetism Using Liquid Nitrogen.

Science.gov (United States)

Simmonds, Ray; And Others

1994-01-01

Describes how liquid nitrogen is attracted to the poles of neodymium magnets. Nitrogen is not paramagnetic, so the attraction suggests that the liquid nitrogen contains a small amount of oxygen, which causes the paramagnetism. (MVL)

Brucella, nitrogen and virulence.

Science.gov (United States)

Ronneau, Severin; Moussa, Simon; Barbier, Thibault; Conde-Álvarez, Raquel; Zuniga-Ripa, Amaia; Moriyon, Ignacio; Letesson, Jean-Jacques

2016-08-01

The brucellae are α-Proteobacteria causing brucellosis, an important zoonosis. Although multiplying in endoplasmic reticulum-derived vacuoles, they cause no cell death, suggesting subtle but efficient use of host resources. Brucellae are amino-acid prototrophs able to grow with ammonium or use glutamate as the sole carbon-nitrogen source in vitro. They contain more than twice amino acid/peptide/polyamine uptake genes than the amino-acid auxotroph Legionella pneumophila, which multiplies in a similar vacuole, suggesting a different nutritional strategy. During these two last decades, many mutants of key actors in nitrogen metabolism (transporters, enzymes, regulators, etc.) have been described to be essential for full virulence of brucellae. Here, we review the genomic and experimental data on Brucella nitrogen metabolism and its connection with virulence. An analysis of various aspects of this metabolism (transport, assimilation, biosynthesis, catabolism, respiration and regulation) has highlighted differences and similarities in nitrogen metabolism with other α-Proteobacteria. Together, these data suggest that, during their intracellular life cycle, the brucellae use various nitrogen sources for biosynthesis, catabolism and respiration following a strategy that requires prototrophy and a tight regulation of nitrogen use.

Enhancing biological nitrogen fixation

Energy Technology Data Exchange (ETDEWEB)

Danso, S.K.A.; Eskew, D.L. (Joint FAO/IAEA Div. of Isotope and Radiation Applications of Atomic Energy for Food and Agricultural Development, Vienna (Austria))

1984-06-01

Several co-ordinated research programmes (CRPs) conducted by the Soil Fertility, Irrigation and Crop Production Section of the Joint FAO/IAEA Division have concentrated on finding the most efficient way of applying nitrogen fertilizers to various crops, using nitrogen-15 (/sup 15/N) as a tracer. The findings of these studies have been adopted in many countries around the world, resulting in savings of nitrogen fertilizers worth many millions of dollars every year. More recently, the Section's CRPs have focused on enhancing the natural process of biological di-nitrogen fixation. The /sup 15/N isotope technique has proven to be very valuable in studies of the legume-Rhizobium symbiosis, allowing many more experiments than before to be done and yielding much new practical information. The Soils Section is now working to extend the use of the technique to other nitrogen-fixing symbioses.

Sensitivity of nitrogen dioxide concentrations to oxides of nitrogen controls in the United Kingdom

International Nuclear Information System (INIS)

Dixon, J.

2001-01-01

There is a possibility of further controls on emissions to the atmosphere of nitrogen dioxides to meet air quality objectives in the UK. Data in the National Air Quality Archive were used to calculate the likely sensitivity of hourly concentrations of nitrogen dioxide in ambient urban air to changes in the total oxides of nitrogen. Since the role of atmospheric chemical reactions is to make the responses non-linearly dependent on the emissions control, we seek to establish the magnitude and sign of the effects that this non-linearity might cause. We develop a quantitative approach to analysing the non-linearity in the data. Polynomial fits have been developed for the empirical ratio NO 2 :NO x (the 'yield'). They describe nitrogen dioxide concentrations using total oxides of nitrogen. The new functions have the important feature of increased yield in winter episodes. Simpler functions tend to omit this feature of the yields at the highest hourly concentrations. Based on this study, the hourly nitrogen dioxide objective in the UK may require emissions control of no more than about 50% on total oxides of nitrogen at the most polluted sites: other sites require less or even no control. (Author)

Nitrogen in rock: Occurrences and biogeochemical implications

Science.gov (United States)

Holloway, J.M.; Dahlgren, R.A.

2002-01-01

There is a growing interest in the role of bedrock in global nitrogen cycling and potential for increased ecosystem sensitivity to human impacts in terrains with elevated background nitrogen concentrations. Nitrogen-bearing rocks are globally distributed and comprise a potentially large pool of nitrogen in nutrient cycling that is frequently neglected because of a lack of routine analytical methods for quantification. Nitrogen in rock originates as organically bound nitrogen associated with sediment, or in thermal waters representing a mixture of sedimentary, mantle, and meteoric sources of nitrogen. Rock nitrogen concentrations range from trace levels (>200 mg N kg -1) in granites to ecologically significant concentrations exceeding 1000 mg N kg -1 in some sedimentary and metasedimentary rocks. Nitrate deposits accumulated in arid and semi-arid regions are also a large potential pool. Nitrogen in rock has a potentially significant impact on localized nitrogen cycles. Elevated nitrogen concentrations in water and soil have been attributed to weathering of bedrock nitrogen. In some environments, nitrogen released from bedrock may contribute to nitrogen saturation of terrestrial ecosystems (more nitrogen available than required by biota). Nitrogen saturation results in leaching of nitrate to surface and groundwaters, and, where soils are formed from ammonium-rich bedrock, the oxidation of ammonium to nitrate may result in soil acidification, inhibiting revegetation in certain ecosystems. Collectively, studies presented in this article reveal that geologic nitrogen may be a large and reactive pool with potential for amplification of human impacts on nitrogen cycling in terrestrial and aquatic ecosystems.

The effect of percentage of nitrogen in plasma gas on nitrogen

African Journals Online (AJOL)

user

1985-09-01

Sep 1, 1985 ... an arc plasma into liquid iron has been investigated by melting iron in an atmosphere of nitrogen and argon using an arc plasma. Results show that both the rate of ..... "Solubility of Nitrogen in arc melted and Levitation-melted.

Nitrogen

Science.gov (United States)

Apodaca, L.E.

2010-01-01

Ammonia was produced by 13 companies at 23 plants in 16 states during 2009. Sixty percent of all U.S. ammonia production capacity was centered in Louisiana. Oklahoma and Texas because of those states' large reserves of natural gas, the dominant domestic feedstock. In 2009, U.S. producers operated at about 83 percent of their rated capacity (excluding plants that were idle for the entire year). Five companies — Koch Nitrogen Co.; Terra Industries Inc.; CF Industries Inc.; PCS Nitrogen Inc. and Agrium Inc., in descending order — accounted for 80 percent of the total U.S. ammonia production capacity. U.S. production was estimated to be 7.7 Mt (8.5 million st) of nitrogen (N) content in 2009 compared with 7.85 Mt (8.65 million st) of N content in 2008. Apparent consumption was estimated to have decreased to 12.1 Mt (13.3 million st) of N, a 10-percent decrease from 2008. The United States was the world's fourth-ranked ammonia producer and consumer following China, India and Russia. Urea, ammonium nitrate, ammonium phosphates, nitric acid and ammonium sulfate were the major derivatives of ammonia in the United States, in descending order of importance.

Nitrogen Cycling in the Mycorrhizosphere: Multipartite Interactions and Plant Nitrogen Uptake Vary with Fertilization Legacy

Science.gov (United States)

Hestrin, R.; Lehmann, J.

2017-12-01

Soil microbes play an important role in rhizosphere nutrient cycling and plant productivity. In this study, the contributions of soil microbes to organic matter mineralization and plant nitrogen uptake were investigated using incubation and microcosm experiments. Microbial inocula included arbuscular mycorrhizal fungi and microbial communities sampled across a long-term gradient of nitrogen fertilization. Stable isotopes, nanoSIMS imaging, and phospholipid fatty acid analysis were used to track carbon and nitrogen movement from organic matter into microbes, mycorrhizal fungi, and plants. Results show that multipartite relationships between plants and microbes increased plant growth and access to nitrogen from organic matter, and that nitrogen fertilization history had a lasting effect on microbial contributions to fungal and plant nitrogen uptake. This research links rhizosphere ecology and land management with terrestrial biogeochemistry.

[Effects of elevated atmospheric CO2 and nitrogen application on cotton biomass, nitrogen utilization and soil urease activity].

Science.gov (United States)

Lyu, Ning; Yin, Fei-hu; Chen, Yun; Gao, Zhi-jian; Liu, Yu; Shi, Lei

2015-11-01

In this study, a semi-open-top artificial climate chamber was used to study the effect of CO2 enrichment (360 and 540 µmol · mol(-1)) and nitrogen addition (0, 150, 300 and 450 kg · hm(-2)) on cotton dry matter accumulation and distribution, nitrogen absorption and soil urease activity. The results showed that the dry matter accumulation of bud, stem, leaf and the whole plant increased significantly in the higher CO2 concentration treatment irrespective of nitrogen level. The dry matter of all the detected parts of plant with 300 kg · hm(-2) nitrogen addition was significantly higher than those with the other nitrogen levels irrespective of CO2 concentration, indicating reasonable nitrogen fertilization could significantly improve cotton dry matter accumulation. Elevated CO2 concentration had significant impact on the nitrogen absorption contents of cotton bud and stem. Compared to those under CO2 concentration of 360 µmol · mol(-1), the nitrogen contents of bud and stem both increased significantly under CO2 concentration of 540 µmol · mol(-1). The nitrogen content of cotton bud in the treatment of 300 kg · hm(-2) nitrogen was the highest among the four nitrogen fertilizer treatments. While the nitrogen contents of cotton stem in the treatments of 150 kg · hm(-2) and 300 kg · hm(-2) nitrogen levels were higher than those in the treatment of 0 kg · hm(-2) and 450 kg · hm(-2) nitrogen levels. The nitrogen content of cotton leaf was significantly influenced by the in- teraction of CO2 elevation and N addition as the nitrogen content of leaf increased in the treatments of 0, 150 and 300 kg · hm(-2) nitrogen levels under the CO2 concentration of 540 µmol · mol(-1). The nitrogen content in cotton root was significantly increased with the increase of nitrogen fertilizer level under elevated CO2 (540 µmol · mol(-1)) treatment. Overall, the cotton nitrogen absorption content under the elevated CO2 (540 µmol · mol(-1)) treatment was higher than that

Evaluation of the Impact of Alveolar Nitrogen Excretion on Indices Derived from Multiple Breath Nitrogen Washout

Science.gov (United States)

Nielsen, Niklas; Nielsen, Jorgen G.; Horsley, Alex R.

2013-01-01

Background A large body of evidence has now accumulated describing the advantages of multiple breath washout tests over conventional spirometry in cystic fibrosis (CF). Although the majority of studies have used exogenous sulphur hexafluoride (SF6) as the tracer gas this has also led to an increased interest in nitrogen washout tests, despite the differences between these methods. The impact of body nitrogen excreted across the alveoli has previously been ignored. Methods A two-compartment lung model was developed that included ventilation heterogeneity and dead space (DS) effects, but also incorporated experimental data on nitrogen excretion. The model was used to assess the impact of nitrogen excretion on washout progress and accuracy of functional residual capacity (FRC) and lung clearance index (LCI) measurements. Results Excreted nitrogen had a small effect on accuracy of FRC (1.8%) in the healthy adult model. The error in LCI calculated with true FRC was greater (6.3%), and excreted nitrogen contributed 21% of the total nitrogen concentration at the end of the washout. Increasing DS and ventilation heterogeneity both caused further increase in measurement error. LCI was increased by 6–13% in a CF child model, and excreted nitrogen increased the end of washout nitrogen concentration by 24–49%. Conclusions Excreted nitrogen appears to have complex but clinically significant effects on washout progress, particularly in the presence of abnormal gas mixing. This may explain much of the previously described differences in washout outcomes between SF6 and nitrogen. PMID:24039916

Modelling the ecosystem effects of nitrogen deposition: Model of Ecosystem Retention and Loss of Inorganic Nitrogen (MERLIN

Directory of Open Access Journals (Sweden)

B. J. Cosby

1997-01-01

Full Text Available A catchment-scale mass-balance model of linked carbon and nitrogen cycling in ecosystems has been developed for simulating leaching losses of inorganic nitrogen. The model (MERLIN considers linked biotic and abiotic processes affecting the cycling and storage of nitrogen. The model is aggregated in space and time and contains compartments intended to be observable and/or interpretable at the plot or catchment scale. The structure of the model includes the inorganic soil, a plant compartment and two soil organic compartments. Fluxes in and out of the ecosystem and between compartments are regulated by atmospheric deposition, hydrological discharge, plant uptake, litter production, wood production, microbial immobilization, mineralization, nitrification, and denitrification. Nitrogen fluxes are controlled by carbon productivity, the C:N ratios of organic compartments and inorganic nitrogen in soil solution. Inputs required are: 1 temporal sequences of carbon fluxes and pools- 2 time series of hydrological discharge through the soils, 3 historical and current external sources of inorganic nitrogen; 4 current amounts of nitrogen in the plant and soil organic compartments; 5 constants specifying the nitrogen uptake and immobilization characteristics of the plant and soil organic compartments; and 6 soil characteristics such as depth, porosity, bulk density, and anion/cation exchange constants. Outputs include: 1 concentrations and fluxes of NO3 and NH4 in soil solution and runoff; 2 total nitrogen contents of the organic and inorganic compartments; 3 C:N ratios of the aggregated plant and soil organic compartments; and 4 rates of nitrogen uptake and immobilization and nitrogen mineralization. The behaviour of the model is assessed for a combination of land-use change and nitrogen deposition scenarios in a series of speculative simulations. The results of the simulations are in broad agreement with observed and hypothesized behaviour of nitrogen

[Interactions of straw, nitrogen fertilizer and bacterivorous nematodes on soil labile carbon and nitrogen and greenhouse gas emissions].

Science.gov (United States)

Zhang, Teng-Hao; Wang, Nan; Liu, Man-Qiang; Li, Fang-Hui; Zhu, Kang-Li; Li, Hui-Xin; Hu, Feng

2014-11-01

A 3 x 2 factorial design of microcosm experiment was conducted to investigate the interactive effects of straw, nitrogen fertilizer and bacterivorous nematodes on soil microbial biomass carbon (C(mic)) and nitrogen (N(mic)), dissolved organic carbon (DOC) and nitrogen (DON), mineral nitrogen (NH(4+)-N and NO(3-)-N), and greenhouse gas (CO2, N2O and CH4) emissions. Results showed that straw amendment remarkably increased the numbers of bacterivorous nematodes and the contents of Cmic and Nmic, but Cmic and Nmic decreased with the increasing dose of nitrogen fertilization. The effects of bacterivorous nematodes strongly depended on either straw or nitrogen fertilization. The interactions of straw, nitrogen fertilization and bacterivorous nematodes on soil DOC, DON and mineral nitrogen were strong. Straw and nitrogen fertilization increased DOC and mineral nitrogen contents, but their influences on DON depended on the bacterivorous nematodes. The DOC and mineral nitrogen were negatively and positively influenced by the bacterivorous nematodes, re- spectively. Straw significantly promoted CO2 and N2O emissions but inhibited CH4 emission, while interactions between nematodes and nitrogen fertilization on emissions of greenhouse gases were obvious. In the presence of straw, nematodes increased cumulative CO2 emissions with low nitrogen fertilization, but decreased CO2 and N2O emissions with high nitrogen fertilization on the 56th day after incubation. In summary, mechanical understanding the soil ecological process would inevitably needs to consider the roles of soil microfauna.

Gas phase adsorption technology for nitrogen isotope separation and its feasibility for highly enriched nitrogen gas production

International Nuclear Information System (INIS)

Inoue, Masaki; Asaga, Takeo

2000-04-01

Highly enriched nitrogen-15 gas is favorable to reduce radioactive carbon-14 production in reactor. The cost of highly enriched nitrogen-15 gas in mass production is one of the most important subject in nitride fuel option in 'Feasibility Study for FBR and Related Fuel Cycle'. In this work gas phase adsorption technology was verified to be applicable for nitrogen isotope separation and feasible to produce highly enriched nitrogen-15 gas in commercial. Nitrogen isotopes were separated while ammonia gas flows through sodium-A type zeolite column using pressure swing adsorption process. The isotopic ratio of eight samples were measured by high resolution mass spectrometry and Fourier transform microwave spectroscopy. Gas phase adsorption technology was verified to be applicable for nitrogen isotope separation, since the isotopic ratio of nitrogen-15 and nitrogen-14 in samples were more than six times as high as in natural. The cost of highly enriched nitrogen-15 gas in mass production were estimated by the factor method. It revealed that highly enriched nitrogen-15 gas could be supplied in a few hundred yen per gram in mass production. (author)

Developments in nitrogen generators

International Nuclear Information System (INIS)

Ayres, C.L.; Abrardo, J.M.; Himmelberger, L.M.

1984-01-01

Three process cycles for the production of nitrogen by the cryogenic separation of air are described in detail. These cycles are: (1) a waste expander cycle; (2) an air expander cycle; and (3) a cycle for producing large quantities of gaseous nitrogen. Each cycle has distinct advantages for various production ranges and delivery pressures. A dicussion of key parameters that must be considered when selecting a cycle to meet specific product requirements is presented. The importance of high plant reliability and a dependable liquid nitrogen back up system is also presented. Lastly, a discussion of plant safety dealing with the hazards of nitrogen, enriched oxygen, and hydrocarbons present in the air is reviewed

Nitrogen from mountain to fjord - Annual report 1993; Nitrogen fra fjell til fjord. Aarsrapport 1993

Energy Technology Data Exchange (ETDEWEB)

Kaste, Oe; Bechmann, M; Toerset, K

1994-07-01

``Nitrogen from mountain to fjord`` is an interdisciplinary research programme which studies the nitrogen cycle from deposition to discharge into the sea. The project includes investigation of the nitrogen budgets for two catchments and selected areas of mountain, heath, forest, crop land and fresh water. The main purpose of the project is to increase the knowledge of uptake and runoff of nitrogen and thus to improve the prediction of future effects on soil, forest, fresh water and fjords. The activities are concentrated about two water courses in Norway: Bjerkreimsvassdraget and Aulivassdraget. In Bjerkreimsvassdraget the nitrate concentration changed only little from 1992 to 1993. Relatively large variations in the nitrate concentrations were found in the forest and heath areas of the system. In Aulivassdraget the nitrogen concentration has changed considerably in 1992 and 1993. The maximum concentration measured in the main river was 13.2 mg N/l. In autumn 1992 and spring 1993 much nitrogen remained in the soil after the poor harvest of 1992 and at that time much nitrogen was carried away by the runoff. 16 refs., 19 figs., 16 tabs.

Ephemeroptera, Plecoptera, and Trichoptera on Isle Royale National Park, USA, compared to mainland species pool and size distribution.

Science.gov (United States)

DeWalt, R Edward; South, Eric J

2015-01-01

Extensive sampling for aquatic insects was conducted in the orders Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies) (EPT) of Isle Royale National Park (ISRO), Michigan, United States of America, during summer 2013. The island was ice covered until 8,000 to 10,000 years ago and is isolated by 22-70 km distance from the mainland. Two hypotheses were examined: that ISRO EPT richness would be much reduced from the mainland, and that the species colonizing ISRO would be of smaller size than mainland, adults presumably using updrafts to bridge the distance from mainland sources. Data sets were developed for known mainland EPT species and size for those species. The first hypothesis was confirmed with the mainland species pool consisting of 417 EPT, while ISRO is known to support 73 species. Richness of EPT is directly related to the number of specimens examined. Small streams supported five EPT species, while 15-25 species were found in larger streams. Lakeshores had intermediate diversity. The second hypothesis was substantiated for stoneflies, but not for mayflies or caddisflies. Stoneflies apparently are poorer fliers than either of the other two orders.

Nitrogen trading tool

Science.gov (United States)

The nitrogen cycle is impacted by human activities, including those that increase the use of nitrogen in agricultural systems, and this impact can be seen in effects such as increased nitrate (NO3) levels in groundwater or surface water resources, increased concentration of nitrous oxide (N2O) in th...

Death on a strange isle: the mortality of the stone workers of Purbeck in the nineteenth century.

Science.gov (United States)

Hinde, Andrew; Edgar, Michael

2010-01-01

This paper analyses the mortality of a group of rural workers in an extractive industry, the stone quarriers of the Isle of Purbeck in the southern English county of Dorset. The analysis uses a database created by nominal record linkage of the census enumerators' books and the Church of England baptism and burial registers to estimate age-specific death rates at all ages for males and females, and hence statistics such as the expectation of life at birth. The results are compared with mortality statistics published by the Registrar General of England and Wales (on the basis of the civil registers of deaths) for the registration district of Wareham, in which Purbeck is situated. The stone quarriers had heavier mortality levels than the rest of the population of Purbeck. Closer inspection, however, reveals that their high mortality was confined to males, and was almost entirely due to especially high mortality among boys aged less than five years. In contrast to the experience of coal and metal ore miners, adult male mortality among stone workers was no higher than that among the general population. The final section of the paper considers possible explanations for these results, and suggests that excess mortality among boys in Purbeck from lung diseases might have been responsible.

Use of stable nitrogen isotope 15N in investigating nitrogen uptake by plants from allylisothiocyanate decomposition products

International Nuclear Information System (INIS)

Dolejskova, J.; Kovar, J.

1976-01-01

The assimilability of nitrogen from allylisothiocyanate or from its nitrogenous decomposition products by plants was investigated using 15 N-labelled allylisothiocyanate. The results show that plant nitrogen assimilation from allylisothiocyanate is the higher, the lower the total nitrogen content of the nutritive medium. (author)

Nitrogen balance during growth of cauliflower

NARCIS (Netherlands)

Everaarts, A.P.

2000-01-01

The potential for loss of nitrogen to the environment during growth of cauliflower was investigated. A comparison was made between cauliflower growth and nitrogen uptake without, and with, nitrogen application of the recommended amount (=225 kg ha-1 minus mineral nitrogen in the soil layer 0–60 cm,

Nitrogen Control in VIM Melts

Science.gov (United States)

Jablonski, P. D.; Hawk, J. A.

NETL has developed a design and control philosophy for the addition of nitrogen to austenitic and ferritic steels. The design approach uses CALPHAD as the centerpiece to predict the level to which nitrogen is soluble in both the melt and the solid. Applications of this technique have revealed regions of "exclusion" in which the alloy, while within specification limits of prescribed, cannot be made by conventional melt processing. Furthermore, other investigations have found that substantial retrograde solubility of nitrogen exists, which can become problematic during subsequent melt processing and/or other finishing operations such as welding. Additionally, the CALPHAD method has been used to adjust primary melt conditions. To that end, nitrogen additions have been made using chrome nitride, silicon nitride, high-nitrogen ferrochrome as well as nitrogen gas. The advantages and disadvantages of each approach will be discussed and NETL experience in this area will be summarized with respect to steel structure.

Nitrogen abundance in Comet Halley

International Nuclear Information System (INIS)

Wyckoff, S.; Tegler, S.C.; Engel, L.

1991-01-01

Data on the nitrogen-containing compounds that observed spectroscopically in the coma of Comet Halley are summarized, and the elemental abundance of nitrogen in the Comet Halley nucleus is derived. It is found that 90 percent of elemental nitrogen is in the dust fraction of the coma, while in the gas fraction, most of the nitrogen is contained in NH3 and CN. The elemental nitrogen abundance in the ice component of the nucleus was found to be deficient by a factor of about 75, relative to the solar photosphere, indicating that the chemical partitioning of N2 into NH3 and other nitrogen compounds during the evolution of the solar nebula cannot account completely for the low abundance ratio N2/NH3 = 0.1, observed in the comet. It is suggested that the low N2/NH3 ratio in Comet Halley may be explained simply by physical fractionation and/or thermal diffusion. 88 refs

Effect of nitrogen supply on leaf growth, leaf nitrogen economy and photosynthetic capacity in potato

NARCIS (Netherlands)

Vos, J.; Putten, van der P.E.L.

1998-01-01

Literature reports show little effect of nitrogen supply on radiation use efficiency in potato and in other dicotyledonous C3 species. This paper tests the hypothesis that potato reduces leaf size rather than leaf nitrogen concentration and photosynthetic capacity when nitrogen is in short supply.

Insects as a Nitrogen Source for Plants

Directory of Open Access Journals (Sweden)

Michael J. Bidochka

2013-07-01

Full Text Available Many plants have evolved adaptations in order to survive in low nitrogen environments. One of the best-known adaptations is that of plant symbiosis with nitrogen-fixing bacteria; this is the major route by which nitrogen is incorporated into plant biomass. A portion of this plant-associated nitrogen is then lost to insects through herbivory, and insects represent a nitrogen reservoir that is generally overlooked in nitrogen cycles. In this review we show three specialized plant adaptations that allow for the recovery of insect nitrogen; that is, plants gaining nitrogen from insects. First, we show specialized adaptations by carnivorous plants in low nitrogen habitats. Insect carnivorous plants such as pitcher plants and sundews (Nepenthaceae/Sarraceniaceae and Drosera respectively are able to obtain substantial amounts of nitrogen from the insects that they capture. Secondly, numerous plants form associations with mycorrhizal fungi that can provide soluble nitrogen from the soil, some of which may be insect-derived nitrogen, obtained from decaying insects or insect frass. Finally, a specialized group of endophytic, insect-pathogenic fungi (EIPF provide host plants with insect-derived nitrogen. These soil-inhabiting fungi form a remarkable symbiosis with certain plant species. They can infect a wide range of insect hosts and also form endophytic associations in which they transfer insect-derived nitrogen to the plant. Root colonizing fungi are found in disparate fungal phylogenetic lineages, indicating possible convergent evolutionary strategies between taxa, evolution potentially driven by access to carbon-containing root exudates.

Nitrogen and energy metabolism of sows during several reproductive cycles in relation to nitrogen intake

NARCIS (Netherlands)

Everts, H.

1994-01-01

By feeding the same diet during pregnancy and lactation sows are fed above the nitrogen requirement during pregnancy due to the relatively high nitrogen requirement during lactation. For feeding closer to the requirements at least two diets are needed: one diet with a low nitrogen content

21 CFR 582.1540 - Nitrogen.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Nitrogen. 582.1540 Section 582.1540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS... Nitrogen. (a) Product. Nitrogen. (b) Conditions of use. This substance is generally recognized as safe when...

Mean age distribution of inorganic soil-nitrogen

Science.gov (United States)

Woo, Dong K.; Kumar, Praveen

2016-07-01

Excess reactive nitrogen in soils of intensively managed landscapes causes adverse environmental impact, and continues to remain a global concern. Many novel strategies have been developed to provide better management practices and, yet, the problem remains unresolved. The objective of this study is to develop a model to characterize the "age" of inorganic soil-nitrogen (nitrate, and ammonia/ammonium). We use the general theory of age, which provides an assessment of the time elapsed since inorganic nitrogen has been introduced into the soil system. We analyze a corn-corn-soybean rotation, common in the Midwest United States, as an example application. We observe two counter-intuitive results: (1) the mean nitrogen age in the topsoil layer is relatively high; and (2) mean nitrogen age is lower under soybean cultivation compared to corn although no fertilizer is applied for soybean cultivation. The first result can be explained by cation-exchange of ammonium that retards the leaching of nitrogen, resulting in an increase in the mean nitrogen age near the soil surface. The second result arises because the soybean utilizes the nitrogen fertilizer left from the previous year, thereby removing the older nitrogen and reducing mean nitrogen age. Estimating the mean nitrogen age can thus serve as an important tool to disentangle complex nitrogen dynamics by providing a nuanced characterization of the time scales of soil-nitrogen transformation and transport processes.

Effects of Watering and Nitrogen Fertilization on Yield and Water and Nitrogen Use Efficiency of Cropping Oil Sunflower

Directory of Open Access Journals (Sweden)

TAN Jian-xin

2015-10-01

Full Text Available The field experiment with split-plot design was conducted to study the effects of the interaction of water and nitrogen fertilization on the growth and yield of oil sunflower, water and nitrogen use efficiency of cropping oil sunflower. This experiment set three irrigation rate treatments, including high irrigation treatment (5 250 m3·hm-2, middle irrigation treatment (3 750 m3·hm-2, low irrigation treatment (2 250 m3·hm-2, and four nitrogen application rate treatments, covering no nitrogen fertilization treatment (0 kg·hm-2, low nitrogen application treatment (120 kg·hm-2, middle nitrogen application treatment (240 kg·hm-2 and high nitrogen application treatment (360 kg·hm-2. The results showed that the nitrogen absorption and nitrogen use efficiency of cropping oil sunflower increased as the irrigation rate increased. With the nitrogen application rate increased, the yield of cropping oil sunflower was increased when the nitrogen application rate was 0~240 kg·hm-2, but beyond the 240 kg·hm-2, there was no significant increase. With the irrigation rate increased, the water consumption amount of cropping oil sunflower increased all the time, but the water use efficiency increased first, and hen decreased. Besides there was no significant difference between 240 kg·hm-2 and 360 kg·hm-2 treatment. Under our experiment condition, during the cropping oil sunflower growth period, when the irrigation rate was 5 250 m3·hm-2 (high irrigation rate and the nitrogen ertilization was 360 m3·hm-2 (high nitrogen application rate, the yield of cropping oil sunflower was 3 598 kg·hm-2. When the irrigation rate was 3 750 m3·hm-2 (middle irrigation rate and the nitrogen fertilization was 240 m3·hm-2 (middle nitrogen application rate, the yield was 3 518 kg·hm-2, with the yield components similar with the high irrigation rate and high nitrogen application rate treatment. Considering various factors, middle irrigation rate and middle nitrogen

46 CFR 154.1755 - Nitrogen.

Science.gov (United States)

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Nitrogen. 154.1755 Section 154.1755 Shipping COAST GUARD... Nitrogen. Except for deck tanks and their piping systems, cargo containment systems and piping systems carrying nitrogen must be specially approved by the Commandant (CG-522). [CGD 74-289, 44 FR 26009, May 3...

[Influence of water deficit and supplemental irrigation on nitrogen uptake by winter wheat and nitrogen residual in soil].

Science.gov (United States)

Wang, Zhaohui; Wang, Bing; Li, Shengxiu

2004-08-01

Pot experiment in greenhouse showed that water deficit at all growth stages and supplemental irrigation at tillering stage significantly decreased the nitrogen uptake by winter wheat and increased the mineral N residual (79.8-113.7 mg x kg(-1)) in soil. Supplemental irrigation at over-wintering, jointing or filling stage significantly increased the nitrogen uptake by plant and decreased the nitrogen residual (47.2-60.3 mg x kg(-1)) in soil. But, the increase of nitrogen uptake caused by supplemental irrigation did not always mean a high magnitude of efficient use of nitrogen by plants. Supplemental irrigation at over-wintering stage didn't induce any significant change in nitrogen content of grain, irrigation at filling stage increased the nitrogen content by 20.9%, and doing this at jointing stage decreased the nitrogen content by 19.6%, as compared to the control.

Extremismo y radicalismo islámico en la Estrategia de Seguridad Nacional 2013: Una visión fragmentada e incompleta

Directory of Open Access Journals (Sweden)

Beatriz Tomé

2014-05-01

Full Text Available A pesar de que el extremismo islámico es una de las cuestiones más relevantes de la agenda internacional de los últimos años, no adquiere una entidad específica en la Estrategia de Seguridad Nacional (ESN. Aparece como un potenciador, que se integra en una concepción compleja y multidimensional de la seguridad y que está relacionado con (a la amenaza terrorista, (b el riesgo de vulnerabilidad energética, y (c el riesgo que supone una posible ausencia de cohesión social. Al descenso en el nivel analítico se añade la confusión conceptual en torno a los términos radicalismo, fundamentalismo y extremismo. Esta falta de precisión, que homogeniza un conjunto de procesos multiformes, imposibilita el diseño de unas líneas de acción precisas y eficaces que señalen los actores específicos con los que colaborar y las áreas concretas sobre las que incidir.

Nitrogen system for the SSC

International Nuclear Information System (INIS)

McAshan, M.; Thirumaleshwar, M.; Abramovich, S.; Ganni, V.

1992-10-01

The Superconducting Super Collider consists of two parallel magnet rings, each 87,120 m in circumference, constructed in a tunnel 25 m to 74 m below ground level. They are operated at a controlled low helium temperature in order to maintain the magnet windings in the superconducting state. To obtain this condition, the magnet cryostat is designed with a high-quality insulation obtained by a high vacuum chamber, multilayer insulation, and thermal shields at nominal temperatures of 84 K and 20 K. Thermal radiation and the conduction heat load through the supports are intercepted and absorbed by the 84-K shield. Liquid nitrogen provides the refrigeration for these loads. The 84-K shield is anchored to two 63.5-mm stainless-steel tubes. One of the tubes, the ''liquid line,'' serves as a conduit in the distribution system of liquid nitrogen. The other tube, the ''vapor line,'' is used to collect the nitrogen vapor generated in the cooling process and to supply this vapor to,the helium refrigerators for precooling. The vapor line may also be used as a continuous cooler by injecting controlled amounts of liquid nitrogen. The nitrogen system consists of nitrogen supplies; ten nitrogen dewars for the collider and two for the High Energy Booster located on the ground at the main shaft entrances; liquid and vapor transfer lines through the shaft to connect the surface and the tunnel systems; and transfer lines to bypass warm equipment sections of the collider. The nitrogen system is expected to operate at steady state condition except for cooldown, warmup, and system repair, for which transients are expected. During normal operation and standby modes of the collider, temperature, pressure, and mass flow are expected to be constant in all circuits of the nitrogen system. The conceptual design requirements for various flow schemes and the engineering considerations are presented in this report

21 CFR 184.1540 - Nitrogen.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Nitrogen. 184.1540 Section 184.1540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1540 Nitrogen. (a) Nitrogen (empirical formula N2, CAS Reg. No. 7727-37-9...

A nitrogen mass balance for California

Science.gov (United States)

Liptzin, D.; Dahlgren, R. A.

2010-12-01

Human activities have greatly altered the global nitrogen cycle and these changes are apparent in water quality, air quality, ecosystem and human health. However, the relative magnitude of the sources of new reactive nitrogen and the fate of this nitrogen is not well established. Further, the biogeochemical aspects of the nitrogen cycle are often studied in isolation from the economic and social implications of all the transformations of nitrogen. The California Nitrogen Assessment is an interdisciplinary project whose aim is evaluating the current state of nitrogen science, practice, and policy in the state of California. Because of the close proximity of large population centers, highly productive and diverse agricultural lands and significant acreage of undeveloped land, California is a particularly interesting place for this analysis. One component of this assessment is developing a mass balance of nitrogen as well as identifying gaps in knowledge and quantifying uncertainty. The main inputs of new reactive nitrogen to the state are 1) synthetic nitrogen fertilizer, 2) biological nitrogen fixation, and 3) atmospheric nitrogen deposition. Permanent losses of nitrogen include 1) gaseous losses (N2, N2O, NHx, NOy), 2) riverine discharge, 3) wastewater discharge to the ocean, and 4) net groundwater recharge. A final term is the balance of food, feed, and fiber to support the human and animal populations. The largest input of new reactive nitrogen to California is nitrogen fertilizer, but both nitrogen fixation and atmospheric deposition contribute significantly. Non-fertilizer uses, such as the production of nylon and polyurethane, constitutes about 5% of the synthetic N synthesized production. The total nitrogen fixation in California is roughly equivalent on the 400,000 ha of alfalfa and the approximately 40 million ha of natural lands. In addition, even with highly productive agricultural lands, the large population of livestock, in particular dairy cows

Odd nitrogen production by meteoroids

Science.gov (United States)

Park, C.; Menees, G. P.

1978-01-01

The process by which odd nitrogen species (atomic nitrogen and nitric oxide) are formed during atmospheric entry of meteoroids is analyzed theoretically. An ablating meteoroid is assumed to be a point source of mass with a continuum regime evolving in its wake. The amounts of odd nitrogen species, produced by high-temperature reactions of air in the continuum wake, are calculated by numerical integration of chemical rate equations. Flow properties are assumed to be uniform across the wake, and 29 reactions involving five neutral species and five singly ionized species are considered, as well as vibrational and electron temperature nonequilibrium phenomena. The results, when they are summed over the observed mass, velocity, and entry-angle distribution of meteoroids, provide odd-nitrogen-species annual global production rates as functions of altitude. The peak production of nitric oxide is found to occur at an altitude of about 85 km; atomic nitrogen production peaks at about 95 km. The total annual rate for nitric oxide is 40 million kg; for atomic nitrogen it is 170 million kg.

Effect of water and nitrogen additions on free-living nitrogen fixer populations in desert grass root zones.

Science.gov (United States)

Herman, R P; Provencio, K R; Torrez, R J; Seager, G M

1993-01-01

In this study we measured changes in population levels of free-living N2-fixing bacteria in the root zones of potted Bouteloua eriopoda and Sporobolus flexuosus plants as well as the photosynthetic indices of the plants in response to added nitrogen, added water, and added water plus nitrogen treatments. In addition, N2 fixer population changes in response to added carbon source and nitrogen were measured in plant-free soil columns. There were significant increases in the numbers of N2 fixers associated with both plant species in the water and the water plus nitrogen treatments. Both treatments increased the photosynthetic index, suggesting that plant exudates were driving N2 fixer population changes. Population increases were greatest in the water plus nitrogen treatments, indicating that added nitrogen was synergistic with added water and suggesting that nitrogen addition spared bacteria the metabolic cost of N2 fixation, allowing greater reproduction. Plant-free column studies demonstrated a synergistic carbon-nitrogen effect when carbon levels were limiting (low malate addition) but not when carbon was abundant (high malate), further supporting this hypothesis. The results of this study indicate the presence of N2 fixer populations which interact with plants and which may play a role in the nitrogen balance of desert grasslands. PMID:8215373

Effects of nonpoint and selected point contaminant sources on stream-water quality and relation to land use in Johnson County, northeastern Kansas, October 2002 through June 2004

Science.gov (United States)

Lee, Casey J.; Mau, D.P.; Rasmussen, T.J.

2005-01-01

Water and sediment samples were collected by the U.S. Geological Survey in 12 watersheds in Johnson County, northeastern Kansas, to determine the effects of nonpoint and selected point contaminant sources on stream-water quality and their relation to varying land use. The streams studied were located in urban areas of the county (Brush, Dykes Branch, Indian, Tomahawk, and Turkey Creeks), developing areas of the county (Blue River and Mill Creek), and in more rural areas of the county (Big Bull, Captain, Cedar, Kill, and Little Bull Creeks). Two base-flow synoptic surveys (73 total samples) were conducted in 11 watersheds, a minimum of three stormflow samples were collected in each of six watersheds, and 15 streambed-sediment sites were sampled in nine watersheds from October 2002 through June 2004. Discharge from seven wastewater treatment facilities (WWTFs) were sampled during base-flow synoptic surveys. Discharge from these facilities comprised greater than 50 percent of streamflow at the farthest downstream sampling site in six of the seven watersheds during base-flow conditions. Nutrients, organic wastewater-indicator compounds, and prescription and nonprescription pharmaceutical compounds generally were found in the largest concentrations during base-flow conditions at sites at, or immediately downstream from, point-source discharges from WWTFs. Downstream from WWTF discharges streamflow conditions were generally stable, whereas nutrient and wastewater-indicator compound concentrations decreased in samples from sites farther downstream. During base-flow conditions, sites upstream from WWTF discharges had significantly larger fecal coliform and Escherichia coli densities than downstream sites. Stormflow samples had the largest suspended-sediment concentrations and indicator bacteria densities. Other than in samples from sites in proximity to WWTF discharges, stormflow samples generally had the largest nutrient concentrations in Johnson County streams. Discharge

The nitrogen cycle on Mars

Science.gov (United States)

Mancinelli, Rocco L.

1989-01-01

Nirtogen is an essential element for the evolution of life, because it is found in a variety of biologically important molecules. Therefore, N is an important element to study from a exobiological perspective. In particular, fixed nitrogen is the biologically useful form of nitrogen. Fixed nitrogen is generally defines as NH3, NH4(+), NO(x), or N that is chemically bound to either inorganic or organic molecules, and releasable by hydrolysis to NH3 or NH4(+). On Earth, the vast majority of nitrogen exists as N2 in the atmosphere, and not in the fixes form. On early Mars the same situations probably existed. The partial pressure of N2 on early Mars was thought to be 18 mb, significantly less than that of Earth. Dinitrogen can be fixed abiotically by several mechanisms. These mechanisms include thernal shock from meteoritic infall and lightning, as well as the interaction of light and sand containing TiO2 which produces NH3 that would be rapidly destroyed by photolysis and reaction with OH radicals. These mechanisms could have been operative on primitive Mars.The chemical processes effecting these compounds and possible ways of fixing or burying N in the Martian environment are described. Data gathered in this laboratory suggest that the low abundance of nitrogen along (compared to primitive Earth) may not significantly deter the origin and early evolution of a nitrogen utilizing organisms. However, the conditions on current Mars with respect to nitrogen are quite different, and organisms may not be able to utilize all of the available nitrogen.

Kinetics of irreversible thermal decomposition of dissociating nitrogen dioxide with nitrogen oxide or oxygen additions

International Nuclear Information System (INIS)

Gvozdev, A.A.

1987-01-01

The effect of NO or O 2 admixtures on kinetics of the irreversible thermal decomposition of nitrogen dioxide at temperatures 460-520 deg C and pressures 4-7 MPa has been studied. It follows from experimental data that the rate of N 2 O 4 formation reduces with the increase of partial pressure of oxygen or decrease of partial pressure of nitrogen oxide. The same regularity is seen for the rate of nitrogen formation. The rate constants of N 2 O formation in dissociating nitrogen tetroxide with oxygen or nitrogen oxide additions agree satisfactorily with previously published results, obtained in stoichiometric mixtures. The appreciable discrepancy at 520 deg C is bind with considerable degree of nitrogen oxide transformation which constitutes approximately 14%. It is determined that the kinetics of formation of the products of irreversible N 2 O and N 2 decomposition in stoichiometric and non-stoichiometric 2NO 2 ↔ 2NO+O 2 mixtures is described by identical 3NO → N 2 O+NO 2 and N 2 O+NO → N 2 +NO 2 reactions

Nitrogen fixation in denitrified marine waters.

Directory of Open Access Journals (Sweden)

Camila Fernandez

Full Text Available Nitrogen fixation is an essential process that biologically transforms atmospheric dinitrogen gas to ammonia, therefore compensating for nitrogen losses occurring via denitrification and anammox. Currently, inputs and losses of nitrogen to the ocean resulting from these processes are thought to be spatially separated: nitrogen fixation takes place primarily in open ocean environments (mainly through diazotrophic cyanobacteria, whereas nitrogen losses occur in oxygen-depleted intermediate waters and sediments (mostly via denitrifying and anammox bacteria. Here we report on rates of nitrogen fixation obtained during two oceanographic cruises in 2005 and 2007 in the eastern tropical South Pacific (ETSP, a region characterized by the presence of coastal upwelling and a major permanent oxygen minimum zone (OMZ. Our results show significant rates of nitrogen fixation in the water column; however, integrated rates from the surface down to 120 m varied by ∼30 fold between cruises (7.5±4.6 versus 190±82.3 µmol m(-2 d(-1. Moreover, rates were measured down to 400 m depth in 2007, indicating that the contribution to the integrated rates of the subsurface oxygen-deficient layer was ∼5 times higher (574±294 µmol m(-2 d(-1 than the oxic euphotic layer (48±68 µmol m(-2 d(-1. Concurrent molecular measurements detected the dinitrogenase reductase gene nifH in surface and subsurface waters. Phylogenetic analysis of the nifH sequences showed the presence of a diverse diazotrophic community at the time of the highest measured nitrogen fixation rates. Our results thus demonstrate the occurrence of nitrogen fixation in nutrient-rich coastal upwelling systems and, importantly, within the underlying OMZ. They also suggest that nitrogen fixation is a widespread process that can sporadically provide a supplementary source of fixed nitrogen in these regions.

Nitrogen Fixation in Denitrified Marine Waters

Science.gov (United States)

Fernandez, Camila; Farías, Laura; Ulloa, Osvaldo

2011-01-01

Nitrogen fixation is an essential process that biologically transforms atmospheric dinitrogen gas to ammonia, therefore compensating for nitrogen losses occurring via denitrification and anammox. Currently, inputs and losses of nitrogen to the ocean resulting from these processes are thought to be spatially separated: nitrogen fixation takes place primarily in open ocean environments (mainly through diazotrophic cyanobacteria), whereas nitrogen losses occur in oxygen-depleted intermediate waters and sediments (mostly via denitrifying and anammox bacteria). Here we report on rates of nitrogen fixation obtained during two oceanographic cruises in 2005 and 2007 in the eastern tropical South Pacific (ETSP), a region characterized by the presence of coastal upwelling and a major permanent oxygen minimum zone (OMZ). Our results show significant rates of nitrogen fixation in the water column; however, integrated rates from the surface down to 120 m varied by ∼30 fold between cruises (7.5±4.6 versus 190±82.3 µmol m−2 d−1). Moreover, rates were measured down to 400 m depth in 2007, indicating that the contribution to the integrated rates of the subsurface oxygen-deficient layer was ∼5 times higher (574±294 µmol m−2 d−1) than the oxic euphotic layer (48±68 µmol m−2 d−1). Concurrent molecular measurements detected the dinitrogenase reductase gene nifH in surface and subsurface waters. Phylogenetic analysis of the nifH sequences showed the presence of a diverse diazotrophic community at the time of the highest measured nitrogen fixation rates. Our results thus demonstrate the occurrence of nitrogen fixation in nutrient-rich coastal upwelling systems and, importantly, within the underlying OMZ. They also suggest that nitrogen fixation is a widespread process that can sporadically provide a supplementary source of fixed nitrogen in these regions. PMID:21687726

Influence of nitrogen loading and plant nitrogen assimilation on nitrogen leaching and N₂O emission in forage rice paddy fields fertilized with liquid cattle waste.

Science.gov (United States)

Riya, Shohei; Zhou, Sheng; Kobara, Yuso; Sagehashi, Masaki; Terada, Akihiko; Hosomi, Masaaki

2015-04-01

Livestock wastewater disposal onto rice paddy fields is a cost- and labor-effective way to treat wastewater and cultivate rice crops. We evaluated the influence of nitrogen loading rates on nitrogen assimilation by rice plants and on nitrogen losses (leaching and N2O emission) in forage rice fields receiving liquid cattle waste (LCW). Four forage rice fields were subjected to nitrogen loads of 107, 258, 522, and 786 kg N ha(-1) (N100, N250, N500, and N750, respectively) using basal fertilizer (chemical fertilizer) (50 kg N ha(-1)) and three LCW topdressings (each 57-284 kg N ha(-1)). Nitrogen assimilated by rice plants increased over time. However, after the third topdressing, the nitrogen content of the biomass did not increase in any treatment. Harvested aboveground biomass contained 93, 60, 33, and 31 % of applied nitrogen in N100, N250, N500, and N750, respectively. The NH4 (+) concentration in the pore water at a depth of 20 cm was less than 1 mg N L(-1) in N100, N250, and N500 throughout the cultivation period, while the NH4 (+) concentration in N750 increased to 3 mg N L(-1) after the third topdressing. Cumulative N2O emissions ranged from -0.042 to 2.39 kg N ha(-1); the highest value was observed in N750, followed by N500. In N750, N2O emitted during the final drainage accounted for 80 % of cumulative N2O emissions. This study suggested that 100-258 kg N ha(-1) is a recommended nitrogen loading rate for nitrogen recovery by rice plants without negative environmental impacts such as groundwater pollution and N2O emission.

Nitrogen-Doped Graphene:Effects of nitrogen species on the properties of the vanadium redox flow battery

International Nuclear Information System (INIS)

Shi, Lang; Liu, Suqin; He, Zhen; Shen, Junxi

2014-01-01

Nitrogen-doped graphene nanosheets (NGS), prepared by a simple hydrothermal reaction of graphene oxide (GO) with urea as nitrogen source were studied as positive electrodes in vanadium redox flow battery (VRFB). The synthesized NGS with the nitrogen level as high as 10.12 atom% is proven to be a promising material for VRFB. The structures and electrochemical properties of the materials are investigated by scanning electron microscopy, X-ray photoelectron spectroscopy, cyclic voltammetry and electrochemical impendence spectroscopy. The results demonstrate that not only the nitrogen doping level but the nitrogen type in the NGS are significant for its catalytic activity towards the [VO] 2+ /[VO 2 ] + redox couple reaction. In more detail, among four types of nitrogen species (pyridinic-N, pyrrolic-N, quaternary-N, oxidic-N) doped into the graphene lattice, quaternary-N play mainly roles for improving the catalytic activity toward the [VO] 2+ /[VO 2 ] + couple reaction

Nitrogen metabolism and microbial production of dairy cows fed sugarcane and nitrogen compounds

OpenAIRE

Gonçalves,Geógenes da Silva; Pedreira,Marcio dos Santos; Pereira,Mara Lúcia Albuquerque; Santos,Dimas Oliveira; Souza,Dicastro Dias de; Porto Junior,Antonio Ferraz

2014-01-01

The aim of this study was to evaluate the effect of dairy cow diets containing two different sources of urea on nitrogen metabolism and microbial synthesis. Eight crossbred cows were confined and distributed in two 4x4 Latin: FS - soybean meal (control), conventional urea (UC) 100%; ULL 44 UC = 56% / 44% ULL, ULL 88 UC = 12% / 88% ULL. Diets were offered to animals during 21 days with 14 days of adaptation. The N intake, retained nitrogen balance, nitrogen excretion in milk, urine, feces and ...

Marine litter abundance and distribution on beaches on the Isle of Rügen considering the influence of exposition, morphology and recreational activities.

Science.gov (United States)

Hengstmann, Elena; Gräwe, Dennis; Tamminga, Matthias; Fischer, Elke Kerstin

2017-02-15

The abundance, weight and composition of marine debris were determined at the northwest coast of the Isle of Rügen in 2015. A total number of 1115 macrolitter items were registered, resulting in an abundance of 304±88.96 items per 100m of beach length and therefore being greater than the abundances found for other beaches at the Baltic Sea. Macrolitter items were predominantly composed of plastic, on average 83%. The four beaches under investigation have different exposition as well as touristic levels. The differing influence of wind and water currents as well as recreational activities on the macrolitter at these beaches was detectable. The distribution of items within a beach segment was analyzed by implementing D-GPS and drone aerial photography. The results of this analysis suggested that the identity of the substrate as well as the presence of vegetation are both major influencing factors in the macrolitter distribution. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nitrogen-containing steels and thermomechanical treatment

International Nuclear Information System (INIS)

Kaputkina, L.; Prokoshkina, V.G.; Svyazhin, G.

2004-01-01

The strengthening of nitrogen-containing corrosion-resistant steels resulting from alloying and thermomechanical treatment have been investigated using X-ray diffraction analysis, light microscopy, hardness measurements and tensile testing. Combined data have been obtained for nitrogen interaction with alloying elements , peculiarities of deformed structure and short-range of nitrogen-containing steels of various structural classes. The higher nitrogen and total alloying element contents, the higher deformation strengthening. Prospects of use the steels with not high nitrogen content and methods of their thermomechanical strengthening are shown. High temperature thermomechanical treatment (HTMT) is very effective for obtaining high and thermally stable constructional strength of nitrogen-containing steels of all classes. The HTMT is most effective if used in a combination with dispersion hardening for aging steels or in the case of mechanically unstable austenitic steels. (author)

Transformation of nitrogen and distribution of nitrogen-related bacteria in a polluted urban stream.

Science.gov (United States)

Jiao, Y; Jin, W B; Zhao, Q L; Zhang, G D; Yan, Y; Wan, J

2009-01-01

Most researchers focused on either nitrogen species or microbial community for polluted urban stream while ignoring the interaction between them and its effect on nitrogen transformation, which restricted the rational selection of an effective and feasible remediation technology. Taking Buji stream in Shenzhen (China) as target stream, the distribution of nitrogen-related bacteria was investigated by most probable number (MPN) besides analysis of nitrogen species etc. The nitrogen-related bacteria in sediment were 10(2) times richer than those in water. Owing to their faster growth, the MPN of ammonifying bacteria and denitrifying bacteria were 10(5) and 10(2) times higher than those of nitrifying bacteria, respectively. The ammonifying bacteria numbers were significantly related to BOD5 in water, while nitrifying bacteria in sediment correlated well with nitrate in water. Thus, nitrification occurred mainly in sediment surface and was limited by low proportion of nitrifying bacteria. The denitrifying bacteria in sediment had good relationship with BOD5 and nitrite and nitrate in water. Low DO and rich organic compounds were beneficial to denitrification but unfavourable to nitrification. Denitrification was restricted by low nitrite and nitrate concentration. These results could be served as a reference for implementing the remediation scheme of nitrogen polluted urban stream.

Fluxes of oxidised and reduced nitrogen above a mixed coniferous forest exposed to various nitrogen emission sources

International Nuclear Information System (INIS)

Neirynck, J.; Kowalski, A.S.; Carrara, A.; Genouw, G.; Berghmans, P.; Ceulemans, R.

2007-01-01

Concentrations of nitrogen gases (NH 3 , NO 2 , NO, HONO and HNO 3 ) and particles (pNH 4 and pNO 3 ) were measured over a mixed coniferous forest impacted by high nitrogen loads. Nitrogen dioxide (NO 2 ) represented the main nitrogen form, followed by nitric oxide (NO) and ammonia (NH 3 ). A combination of gradient method (NH 3 and NO x ) and resistance modelling techniques (HNO 3 , HONO, pNH 4 and pNO 3 ) was used to calculate dry deposition of nitrogen compounds. Net flux of NH 3 amounted to -64 ng N m -2 s -1 over the measuring period. Net fluxes of NO x were upward (8.5 ng N m -2 s -1 ) with highest emission in the morning. Fluxes of other gases or aerosols substantially contributed to dry deposition. Total nitrogen deposition was estimated at -48 kg N ha -1 yr -1 and consisted for almost 80% of NH x . Comparison of throughfall nitrogen with total deposition suggested substantial uptake of reduced N (±15 kg N ha -1 yr -1 ) within the canopy. - Reduced nitrogen was found to be the main contributor to total deposition which was predominantly governed by dry deposition

Virtual Nitrogen Losses from Organic Food Production

Science.gov (United States)

Cattell Noll, L.; Galloway, J. N.; Leach, A. M.; Seufert, V.; Atwell, B.; Shade, J.

2015-12-01

Reactive nitrogen (Nr) is necessary for crop and animal production, but when it is lost to the environment, it creates a cascade of detrimental environmental impacts. The nitrogen challenge is to maximize the food production benefits of Nr, while minimizing losses to the environment. The first nitrogen footprint tool was created in 2012 to help consumers learn about the Nr losses to the environment that result from an individual's lifestyle choices. The nitrogen lost during food production was estimated with virtual nitrogen factors (VNFs) that quantify the amount of nitrogen lost to the environment per unit nitrogen consumed. Alternative agricultural systems, such as USDA certified organic farms, utilize practices that diverge from conventional production. In order to evaluate the potential sustainability of these alternative agricultural systems, our team calculated VNFs that reflect organic production. Initial data indicate that VNFs for organic grains and organic starchy roots are comparable to, but slightly higher than conventional (+10% and +20% respectively). In contrast, the VNF for organic vegetables is significantly higher (+90%) and the VNF for organic legumes is significantly lower (-90%). Initial data on organic meat production shows that organic poultry and organic pigmeat are comparable to conventional production (both <5% difference), but that the organic beef VNF is significantly higher (+30%). These data show that in some cases organic and conventional production are comparable in terms of nitrogen efficiency. However, since conventional production relies heavily on the creation of new reactive nitrogen (Haber-Bosch, biological nitrogen fixation) and organic production primarily utilizes already existing reactive nitrogen (manure, crop residue, compost), the data also show that organic production contributes less new reactive nitrogen to the environment than conventional production (approximately 70% less). Therefore, we conclude that on a local

Modeling nitrogen fluxes in Germany - where does the nitrogen go?

Science.gov (United States)

Klement, Laura; Bach, Martin; Breuer, Lutz

2016-04-01

According to the latest inventory of the EU Water Framework Directive, 26.3% of German groundwater bodies are in a poor chemical state regarding nitrate. Additionally, the EU initiated infringement proceedings against Germany for not meeting the quality standards of the EU Nitrate Directive. Agriculture has been determined as the main source of nitrate pollution due to over-fertilization and regionally high density of livestock farming. The nitrogen balance surplus is commonly used as an indicator characterizing the potential of nitrate leaching into groundwater bodies and thus also serves as a foundation to introduce legislative restrictions or to monitor the success of mitigation measures. Currently, there is an ongoing discussion which measures are suitable for reducing the risk of nitrate leaching and also to what extent. However, there is still uncertainty about just how much the nitrogen surplus has to be reduced to meet the groundwater quality standards nationwide. Therefore, the aims of our study were firstly to determine the level of the nitrogen surplus that would be acceptable at the utmost and secondly whether the currently discussed target value of 30 kg N per hectare agricultural land for the soil surface nitrogen balance would be sufficient. The models MONERIS (Modeling Nutrient Emissions in River System) and MoRE (Modelling of Regionalized Emissions), the latter based on the first, are commonly used for estimating nitrogen loads into the river system in Germany at the mesoscale, as well as the effect of mitigation measures in the context of the EU directive 2008/105/EC (Environmental quality standards applicable to surface water). We used MoRE to calculate nitrate concentration for 2759 analytical units in Germany. Main factors are the surplus of the soil surface nitrogen balance, the percolation rate and an exponent representing the denitrification in the vadose zone. The modeled groundwater nitrate concentrations did not correspond to the regional

Effects of nitrogen and nitrogen getters in lithium on the corrosion of type 316 stainless steel

International Nuclear Information System (INIS)

Tortorelli, P.F.; DeVan, J.H.; Selle, J.E.

1979-01-01

This paper presents preliminary results on the corrosion of type 316 stainless steel in nitrogen-contaminated lithium. Nitrogen is a principal interstitial impurity in lithium and has a significant detrimental effect on compatibility, while O, H, and C in lithium do not enhance corrosion of type 316 stainless steel. Because of this, there is a need to understand the corrosion mechanisms and kinetics associated with nitrogen-induced attack in lithium. Results from experiments with getters in nitrogen-contaminated lithium are also reported

Effects of split nitrogen fertilization on post-anthesis photoassimilates, nitrogen use efficiency and grain yield in malting barley

DEFF Research Database (Denmark)

Cai, Jian; Jiang, Dong; Liu, Fulai

2011-01-01

photosynthesis after anthesis, dry matter accumulation and assimilates remobilization, nitrogen use efficiency and grain yield to fraction of topdressed nitrogen treatments were investigated in malting barley. Net photosynthetic rate of the penultimate leaf, leaf area index and light extinction coefficient...... assimilation rate and nitrogen use efficiency resulting in higher grain yields and proper grain protein content in malting barley.......Split nitrogen applications are widely adopted to improve grain yield and enhance nitrogen use effective in crops. In a twoyear field experiment at two eco-sites, five fractions of topdressed nitrogen of 0%, 20%, 30%, 40% and 50% were implemented. Responses of radiation interception and leaf...

Carbon and nitrogen isotopic signatures and nitrogen profile to identify adulteration in organic fertilizers.

Science.gov (United States)

Verenitch, Sergei; Mazumder, Asit

2012-08-29

Recently it has been shown that stable isotopes of nitrogen can be used to discriminate between organic and synthetic fertilizers, but the robustness of the approach is questionable. This work developed a comprehensive method that is far more robust in identifying an adulteration of organic nitrogen fertilizers. Organic fertilizers of various types (manures, composts, blood meal, bone meal, fish meal, products of poultry and plant productions, molasses and seaweed based, and others) available on the North American market were analyzed to reveal the most sensitive criteria as well as their quantitative ranges, which can be used in their authentication. Organic nitrogen fertilizers of known origins with a wide δ(15)N range between -0.55 and 28.85‰ (n = 1258) were characterized for C and N content, δ(13)C, δ(15)N, viscosity, pH, and nitrogen profile (urea, ammonia, organic N, water insoluble N, and NO3). A statistically significant data set of characterized unique organic nitrogen fertilizers (n = 335) of various known origins has been assembled. Deliberately adulterated samples of different types of organic fertilizers mixed with synthetic fertilizers at a wide range of proportions have been used to develop the quantitative critical characteristics of organic fertilizers as the key indicators of their adulteration. Statistical analysis based on the discriminant functions of the quantitative critical characteristics of organic nitrogen fertilizers from 14 different source materials revealed a very high average rate of correct classification. The developed methodology has been successfully used as a source identification tool for numerous commercial nitrogen fertilizers available on the North American market.

Experimental study of nitrogen oxide absorption by a liquid nitrogen tetroxide flow

International Nuclear Information System (INIS)

Verzhinskaya, A.B.; Saskovets, V.V.; Borovik, T.F.

1984-01-01

The system of N 2 O 4 based coolant regeneration needs productive and efficient absorbers, providing effective production of nitrogen oxide, decreasing upon NPP operation at the expense of radiation-thermal decomposition. The experimental istallation flowsheet for studying the nitrogen oxide absorbtion by liquid nitrogen tetroxide is given. The experiments have been carried out in removable test sections, looked like helical tubes with internal steam-and-liquid mixture flow and external water cooling. Six test sections with variable geometry factors have been manufactured. The plotted results of the experiments are given as dependences of extraction level and mass transfer volumetric coefficients on the geometry factor, pressure and Froude number

Experimental study of nitrogen oxide absorption by a liquid nitrogen tetroxide flow

Energy Technology Data Exchange (ETDEWEB)

Verzhinskaya, A B; Saskovets, V V; Borovik, T F

1984-01-01

The system of N/sub 2/O/sub 4/ based coolant regeneration needs productive and efficient absorbers, providing effective production of nitrogen oxide, decreasing upon NPP operation at the expense of radiation-thermal decomposition. The experimental istallation flowsheet for studying the nitrogen oxide absorbtion by liquid nitrogen tetroxide is given. The experiments have been carried out in removable test sections, looked like helical tubes with internal steam-and-liquid mixture flow and external water cooling. Six test sections with variable geometry factors have been manufactured. The plotted results of the experiments are given as dependences of extraction level and mass transfer volumetric coefficients on the geometry factor, pressure and Froude number.

Effect of combined N applied at low level on the nitrogen fixation by grasses and contribution to nitrogen fertility in soil

International Nuclear Information System (INIS)

Yao Yunyin; Chen Ming; Ma Changlin

1990-01-01

This paper reports the study on the effect of combined N applied at low level on teh nitrogen fixation by alfalfa in monoculture and mixed culture with meadow fescue, and the effect on the absorption and utilization of indigenous soil nitrogen and nitrogen fertilizer. Amount of nitrogen fixed by alfalfa could be raised and duration of high peak of symbiotic nitrogen fixation activity could be extended when nitrogen fertilizer was applied reasonably. It was especially important for the early pastures or pastures with low supporting nitrogen capacity. Transfer of nitrogen fixed by alfalfa to meadow fescue occured in mixed culture. Nitrogen fixed from alfalfa was uptaken more easily than indigenous nitrogen in soil. Planting alfalfa could raise soil fertility significantly. Meadow fescue may be able to fix nitrogen from the air in some way. When combined N was appropriately applied to soil, on which alfalfa and meadow fescue had been planted, it could promote increasing nitrogen fertility in soil

BOOK REVIEWS BOEKRESE ISlES

African Journals Online (AJOL)

colour-picture ever must be that of Lactrodactu mactans (black widow spider); incidentally the button pider is mi ing. Altogether this book must be considered one of the best general text-books of medicine. It is of particular use to student, and for the most part the articles can be recommended as being highly authoritative. P.l..

“El florecimiento del terrorismo islámico en el Sahel, un reto para la seguridad de Europa Occidental. Estudio de caso: Malí y España (2011- 2013)”

OpenAIRE

Rodríguez Uribe, Mónica Alejandra

2015-01-01

El objetivo central de este Estudio de Caso, consiste en investigar en qué sentido la proximidad geográfica y el hecho de que la región del Sahel constituya una zona de tránsito, influyen a que el crecimiento del terrorismo islámico en Malí comprenda una amenaza tanto para la seguridad nacional, como para la estabilidad de España. Se avanzará posteriormente con la descripción de herramientas específicas, tanto judiciales como de cooperación que el gobierno español ha buscado apoyar a nivel ...

Cascading costs: an economic nitrogen cycle.

Science.gov (United States)

Moomaw, William R; Birch, Melissa B L

2005-09-01

The chemical nitrogen cycle is becoming better characterized in terms of fluxes and reservoirs on a variety of scales. Galloway has demonstrated that reactive nitrogen can cascade through multiple ecosystems causing environmental damage at each stage before being denitrified to N(2). We propose to construct a parallel economic nitrogen cascade (ENC) in which economic impacts of nitrogen fluxes can be estimated by the costs associated with each stage of the chemical cascade. Using economic data for the benefits of damage avoided and costs of mitigation in the Chesapeake Bay basin, we have constructed an economic nitrogen cascade for the region. Since a single ton of nitrogen can cascade through the system, the costs also cascade. Therefore evaluating the benefits of mitigating a ton of reactive nitrogen released needs to consider the damage avoided in all of the ecosystems through which that ton would cascade. The analysis reveals that it is most cost effective to remove a ton of nitrogen coming from combustion since it has the greatest impact on human health and creates cascading damage through the atmospheric, terrestrial, aquatic and coastal ecosystems. We will discuss the implications of this analysis for determining the most cost effective policy option for achieving environmental quality goals.

Gene Deletions Resulting in Increased Nitrogen Release by Azotobacter vinelandii: Application of a Novel Nitrogen Biosensor

Science.gov (United States)

Eberhart, Lauren J.; Ohlert, Janet M.; Knutson, Carolann M.; Plunkett, Mary H.

2015-01-01

Azotobacter vinelandii is a widely studied model diazotrophic (nitrogen-fixing) bacterium and also an obligate aerobe, differentiating it from many other diazotrophs that require environments low in oxygen for the function of the nitrogenase. As a free-living bacterium, A. vinelandii has evolved enzymes and transporters to minimize the loss of fixed nitrogen to the surrounding environment. In this study, we pursued efforts to target specific enzymes and further developed screens to identify individual colonies of A. vinelandii producing elevated levels of extracellular nitrogen. Targeted deletions were done to convert urea into a terminal product by disrupting the urease genes that influence the ability of A. vinelandii to recycle the urea nitrogen within the cell. Construction of a nitrogen biosensor strain was done to rapidly screen several thousand colonies disrupted by transposon insertional mutagenesis to identify strains with increased extracellular nitrogen production. Several disruptions were identified in the ammonium transporter gene amtB that resulted in the production of sufficient levels of extracellular nitrogen to support the growth of the biosensor strain. Further studies substituting the biosensor strain with the green alga Chlorella sorokiniana confirmed that levels of nitrogen produced were sufficient to support the growth of this organism when the medium was supplemented with sufficient sucrose to support the growth of the A. vinelandii in coculture. The nature and quantities of nitrogen released by urease and amtB disruptions were further compared to strains reported in previous efforts that altered the nifLA regulatory system to produce elevated levels of ammonium. These results reveal alternative approaches that can be used in various combinations to yield new strains that might have further application in biofertilizer schemes. PMID:25888177

Nitrogen fixation, denitrification, and ecosystem nitrogen pools in relation to vegetation development in the Subarctic

DEFF Research Database (Denmark)

Sørensen, Pernille Lærkedal; Jonasson, Sven Evert; Michelsen, Anders

2006-01-01

Nitrogen (N) fixation, denitrification, and ecosystem pools of nitrogen were measured in three subarctic ecosystem types differing in soil frost-heaving activity and vegetation cover. N2-fixation was measured by the acetylene reduction assay and converted to absolute N ecosystem input by estimates...... of conversion factors between acetylene reduction and 15N incorporation. One aim was to relate nitrogen fluxes and nitrogen pools to the mosaic of ecosystem types of different stability common in areas of soil frost movements. A second aim was to identify abiotic controls on N2-fixation by simultaneous...... measurements of temperature, light, and soil moisture. Nitrogen fixation rate was high with seasonal input estimated at 1.1 g N m2 on frostheaved sorted circles, which was higher than the total plant N content and exceeded estimated annual plant N uptake several-fold but was lower than the microbial N content...

Cyclic variations in nitrogen uptake rate of soybean plants: ammonium as a nitrogen source

Science.gov (United States)

Henry, L. T.; Raper, C. D. Jr

1989-01-01

When NO3- is the sole nitrogen source in flowing solution culture, the net rate of nitrogen uptake by nonnodulated soybean (Glycine max L. Merr. cv Ransom) plants cycles between maxima and minima with a periodicity of oscillation that corresponds with the interval of leaf emergence. Since soybean plants accumulate similar quantities of nitrogen when either NH4+ or NO3- is the sole source in solution culture controlled at pH 6.0, an experiment was conducted to determine if the oscillations in net rate of nitrogen uptake also occur when NH4+ is the nitrogen source. During a 21-day period of vegetative development, net uptake of NH4+ was measured daily by ion chromatography as depletion of NH4+ from a replenished nutrient solution containing 1.0 millimolar NH4+. The net rate of NH4+ uptake oscillated with a periodicity that was similar to the interval of leaf emergence. Instances of negative net rates of uptake indicate that the transition between maxima and minima involved changes in influx and efflux components of net NH4+ uptake.

An Enhancer Near ISL1 and an Ultraconserved Exon of PCBP2 areDerived from a Retroposon

Energy Technology Data Exchange (ETDEWEB)

Bejerano, Gill; Lowe, Craig; Ahituv, Nadav; King, Bryan; Siepel,Adam; Salama, Sofie; Rubin, Edward M.; Kent, W. James; Haussler, David

2005-11-27

Hundreds of highly conserved distal cis-regulatory elementshave been characterized to date in vertebrate genomes1. Many thousandsmore are predicted based on comparative genomics2,3. Yet, in starkcontrast to the genes they regulate, virtually none of these regions canbe traced using sequence similarity in invertebrates, leaving theirevolutionary origin obscure. Here we show that a class of conserved,primarily non-coding regions in tetrapods originated from a novel shortinterspersed repetitive element (SINE) retroposon family that was activein Sarcopterygii (lobe-finned fishes and terrestrial vertebrates) in theSilurian at least 410 Mya4, and, remarkably, appears to be recentlyactive in the "living fossil" Indonesian coelacanth, Latimeriamenadoensis. We show that one copy is a distal enhancer, located 500kbfrom the neuro-developmental gene ISL1. Several others represent new,possibly regulatory, alternatively spliced exons in the middle ofpre-existing Sarcopterygian genes. One of these is the>200bpultraconserved region5, 100 percent identical in mammals, and 80 percentidentical to the coelacanth SINE, that contains a 31aa alternativelyspliced exon of the mRNA processing gene PCBP26. These add to a growinglist of examples7 in which relics of transposable elements have acquireda function that serves their host, a process termed "exaptation"8, andprovide an origin for at least some of the highly-conservedvertebrate-specific genomic sequences recently discovered usingcomparative genomics.

Preparation and use of nitrogen (2) oxide of special purity for production of oxygen and nitrogen isotopes

International Nuclear Information System (INIS)

Polevoj, A.S.

1989-01-01

Problems related with production of oxygen and nitrogen isotopes by means of low-temperature rectification of nitrogen (2) oxide are analyzed. Special attention, in particular, is payed to the techniques of synthesis and high purification of initial NO, utilization of waste flows formed during isotope separation. Ways to affect the initial isotope composition of nitrogen oxide and the rate of its homogeneous-isotope exchange, which provide for possibility of simultaneous production of oxygen and nitrogen isotopes by means of NO rectification, are considered. Description of a new technique for high purification of nitrogen oxide, prepared at decomposition of nitric acid by sulfurous anhydride, suggested by the author is presented

Next Generation Carbon-Nitrogen Dynamics Model

Science.gov (United States)

Xu, C.; Fisher, R. A.; Vrugt, J. A.; Wullschleger, S. D.; McDowell, N. G.

2012-12-01

Nitrogen is a key regulator of vegetation dynamics, soil carbon release, and terrestrial carbon cycles. Thus, to assess energy impacts on the global carbon cycle and future climates, it is critical that we have a mechanism-based and data-calibrated nitrogen model that simulates nitrogen limitation upon both above and belowground carbon dynamics. In this study, we developed a next generation nitrogen-carbon dynamic model within the NCAR Community Earth System Model (CESM). This next generation nitrogen-carbon dynamic model utilized 1) a mechanistic model of nitrogen limitation on photosynthesis with nitrogen trade-offs among light absorption, electron transport, carboxylation, respiration and storage; 2) an optimal leaf nitrogen model that links soil nitrogen availability and leaf nitrogen content; and 3) an ecosystem demography (ED) model that simulates the growth and light competition of tree cohorts and is currently coupled to CLM. Our three test cases with changes in CO2 concentration, growing temperature and radiation demonstrate the model's ability to predict the impact of altered environmental conditions on nitrogen allocations. Currently, we are testing the model against different datasets including soil fertilization and Free Air CO2 enrichment (FACE) experiments across different forest types. We expect that our calibrated model will considerably improve our understanding and predictability of vegetation-climate interactions.itrogen allocation model evaluations. The figure shows the scatter plots of predicted and measured Vc,max and Jmax scaled to 25 oC (i.e.,Vc,max25 and Jmax25) at elevated CO2 (570 ppm, test case one), reduced radiation in canopy (0.1-0.9 of the radiation at the top of canopy, test case two) and reduced growing temperature (15oC, test case three). The model is first calibrated using control data under ambient CO2 (370 ppm), radiation at the top of the canopy (621 μmol photon/m2/s), the normal growing temperature (30oC). The fitted model

Enhanced nitrogen deposition over China

Energy Technology Data Exchange (ETDEWEB)

Liu, Xuejun; Zhang, Ying; Han, Wenxuan; Tang, Aohan; Shen, Jianlin; Cui, Zhenling; Christie, Peter; Zhang, Fusuo [College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China); Vitousek, Peter [Department of Biology, Stanford University, Stanford, California 94305 (United States); Erisman, Jan Willem [VU University Amsterdam, 1081 HV Amsterdam (Netherlands); Goulding, Keith [The Sustainable Soils and Grassland Systems Department, Rothamsted Research, Harpenden AL5 2JQ (United Kingdom); Fangmeier, Andreas [Institute of Landscape and Plant Ecology, University of Hohenheim, 70593 Stuttgart (Germany)

2013-02-28

China is experiencing intense air pollution caused in large part by anthropogenic emissions of reactive nitrogen. These emissions result in the deposition of atmospheric nitrogen (N) in terrestrial and aquatic ecosystems, with implications for human and ecosystem health, greenhouse gas balances and biological diversity. However, information on the magnitude and environmental impact of N deposition in China is limited. Here we use nationwide data sets on bulk N deposition, plant foliar N and crop N uptake (from long-term unfertilized soils) to evaluate N deposition dynamics and their effect on ecosystems across China between 1980 and 2010. We find that the average annual bulk deposition of N increased by approximately 8 kilograms of nitrogen per hectare (P < 0.001) between the 1980s (13.2 kilograms of nitrogen per hectare) and the 2000s (21.1 kilograms of nitrogen per hectare). Nitrogen deposition rates in the industrialized and agriculturally intensified regions of China are as high as the peak levels of deposition in northwestern Europe in the 1980s, before the introduction of mitigation measures. Nitrogen from ammonium (NH4+) is the dominant form of N in bulk deposition, but the rate of increase is largest for deposition of N from nitrate (NO3-), in agreement with decreased ratios of NH3 to NOx emissions since 1980. We also find that the impact of N deposition on Chinese ecosystems includes significantly increased plant foliar N concentrations in natural and semi-natural (that is, non-agricultural) ecosystems and increased crop N uptake from long-term-unfertilized croplands. China and other economies are facing a continuing challenge to reduce emissions of reactive nitrogen, N deposition and their negative effects on human health and the environment.

Recent studies of the ocean nitrogen cycle

Science.gov (United States)

Eppley, R. W.

1984-01-01

The nitrogen cycle in the ocean is dominated by the activities of organisms. External nitrogen inputs from land and from the atmosphere are small compared with rates of consumption and production by organisms and with rates of internal rearrangements of nitrogen pools within the ocean. The chief reservoirs of nitrogen are, in decreasing order of size: nitrogen in sediments, dissolved N2, nitrate, dissolved organic nitrogen (DON), particulate organic nitrogen (PON) (mostly organisms and their by-products). The biogenic fluxes of nitrogen were reviewed. The rate of PON decomposition in the surface layer must be comparable to the rate of ammonium consumption; and at the same time the nitrate consumption rate will be similar to the rates of: (1) sinking of PON out of the surface layer and its decompositon at depth, (2) the rate of nitrification at depth, and (3) the rate of nitrate return to the surface layer by upwelling.

Development of commercial nitrogen-rich stainless steels

International Nuclear Information System (INIS)

Liljas, M.

1999-01-01

This paper reviews the development of nitrogen alloyed stainless steels. Nitrogen alloying of austenitic stainless steels started at an early stage and was to a large extent caused by nickel shortage. However, direct technical advantages such as increased strength of the nitrogen alloyed steels made them attractive alternatives to the current steels. It was not until the advent of the AOD (argon oxygen decarburisation) process in the late 1960s that nitrogen alloying could be controlled to such accuracy that it became successful commercially on a broader scale. The paper describes production aspects and how nitrogen addition influences microstructure and the resulting properties of austenitic and duplex stainless steels. For austenitic steels there are several reasons for nitrogen alloying. Apart from increasing strength nitrogen also improves structural stability, work hardening and corrosion resistance. For duplex steels nitrogen also has a decisive effect in controlling the microstructure during thermal cycles such as welding. (orig.)

Structural behaviour of nitrogen in oxide ceramics

International Nuclear Information System (INIS)

Ghauri, K.M.

1997-01-01

The solubility of nitrogen in molten oxides has significant consideration for two quite different types of engineering materials. The implication of a knowledge of the role of nitrogen in these oxides for refining high nitrogen steels in obvious but similar nitrogen-bearing oxide melts are of critical importance in the densification of silicon nitride ceramics. Present paper discusses structural behaviour and phase equilibria qualitatively in the light of knowledge available on slag structure through infrared and x-ray diffraction. Nitrogen solubility in glasses and related sialon based ceramics may be of paramount importance to understand the role of nitrogen in these materials as these oxides are similar in composition, structure and characteristics to sintering glasses in nitrogen ceramics. It is quite logical to infer that the same oxide model can be applied in order to massively produce nitrogen alloyed steels which are actively competing to be the materials of the next century. (author)

Protein Losses and Urea Nitrogen Underestimate Total Nitrogen Losses in Peritoneal Dialysis and Hemodialysis Patients.

Science.gov (United States)

Salame, Clara; Eaton, Simon; Grimble, George; Davenport, Andrew

2018-04-28

Muscle wasting is associated with increased mortality and is commonly reported in dialysis patients. Hemodialysis (HD) and peritoneal dialysis (PD) treatments lead to protein losses in effluent dialysate. We wished to determine whether changes in current dialysis practice had increased therapy-associated nitrogen losses. Cross-sectional cohort study. Measurement of total protein, urea and total nitrogen in effluent dialysate from 24-hour collections from PD patients, and during haemodiafiltration (HDF) and haemodialysis (HD) sessions. One hundred eight adult dialysis patients. Peritoneal dialysis, high-flux haemodialysis and haemodiafiltration. Total nitrogen and protein losses. Dialysate protein losses were measured in 68 PD and 40 HD patients. Sessional losses of urea (13.9 [9.2-21.1] vs. 4.8 [2.8-7.8] g); protein (8.6 [7.2-11.1] vs. 6.7 [3.9-11.1] g); and nitrogen (11.5 [8.7-17.7] vs. 4.9 [2.6-9.5] g) were all greater for HD than PD, P losses were lower with HD 25.9 (21.5-33.4) versus 46.6 (27-77.6) g/week, but nitrogen losses were similar. We found no difference between high-flux HD and HDF: urea (13.5 [8.8-20.6] vs. 15.3 [10.5-25.5] g); protein (8.8 [7.3-12.2] vs. 7.6 [5.8-9.0] g); and total nitrogen (11.6 [8.3-17.3] vs. 10.8 [8.9-22.5] g). Urea nitrogen (UN) only accounted for 45.1 (38.3-51.0)% PD and 63.0 (55.3-62.4)% HD of total nitrogen losses. Although sessional losses of protein and UN were greater with HD, weekly losses were similar between modalities. We found no differences between HD and HDF. However, total nitrogen losses were much greater than the combination of protein and UN, suggesting greater nutritional losses with dialysis than previously reported. Copyright © 2018 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Nitrogen use efficiency (NUE)

NARCIS (Netherlands)

Oenema, O.

2015-01-01

There is a need for communications about resource use efficiency and for measures to increase the use efficiency of nutrients in relation to food production. This holds especially for nitrogen. Nitrogen (N) is essential for life and a main nutrient element. It is needed in relatively large

Ammonia Nitrogen Added to Diets Deficient in Dispensable Amino Acid Nitrogen Is Poorly Utilized for Urea Production in Growing Pigs.

Science.gov (United States)

Mansilla, Wilfredo D; Silva, Kayla E; Zhu, Cuilan L; Nyachoti, Charles M; Htoo, John K; Cant, John P; de Lange, Cornelis Fm

2017-12-01

Background: Including ammonia in low-crude protein (CP) diets deficient in dispensable amino acid (DAAs) increases nitrogen retention in growing pigs. Objective: We investigated the absorption and metabolism of dietary ammonia nitrogen in the portal-drained viscera (PDV) and liver of pigs fed a diet deficient in DAA nitrogen. Methods: Eight pigs with an initial mean ± SD body weight (BW) of 26.5 ± 1.4 kg were surgically fitted with 4 catheters each (portal, hepatic and mesenteric veins, and carotid artery). The pigs were fed (2.8 × 191 kcal/kg BW 0.60 ), for 7 d and every 8 h, a diet deficient in DAA nitrogen supplemented with increasing amounts of ammonia nitrogen (CP: 7.76%, 9.27%, and 10.77%; indispensable amino acid nitrogen:total nitrogen ratio: 0.71, 0.59, and 0.50 for control and low- and high-ammonia diets, respectively). The treatment sequence was based on a Latin square design with 3 consecutive periods. On the last day of each period, blood flows in the portal and hepatic veins were determined with a continuous infusion of ρ-amino hippuric acid into the mesenteric vein. Serial blood samples were taken to determine ammonia and urea nitrogen concentration. Net balances of ammonia and urea nitrogen were calculated for the PDV and liver. Results: Cumulative (8 h) ammonia nitrogen appearance in the portal vein increased ( P ≤ 0.05) with ammonia intake (433, 958, and 1629 ± 60 mg ammonia nitrogen/meal for control and low- and high-ammonia diets, respectively). The cumulative hepatic uptake of ammonia nitrogen increased ( P ≤ 0.05) with ammonia nitrogen supply. The cumulative urea nitrogen appearance in the hepatic vein tended to increase ( P ≤ 0.10) only in high-ammonia treatment (-92.5, -59.4, and 209.7 ± 92 mg urea nitrogen/meal for control and low- and high-ammonia diets, respectively) and, relative to the control diet, represented -6.0% and 11% of ammonia nitrogen intake. Conclusion: Dietary ammonia nitrogen is poorly utilized for urea

Nitrogen control of photosynthetic protein synthesis

Energy Technology Data Exchange (ETDEWEB)

Schmidt, G.W.

1986-09-01

Plant growth is severely affected by impaired photosynthesis resulting from nitrogen deficiency. The molecular aspects of this effect are being studied in the green alga Chlamydomonas grown in continuous culture systems. Photosynthetic membranes of nitrogen-limited cells are dramatically depleted in chlorophylls, xanthophylls and proteins of the light-harvesting complexes. In contrast, enzymes of the reductive pentose phosphate cycle and electron transport chain complexes are reduced only 40 to 65% on a per cell basis comparison with nitrogen-sufficient cultures. From analyses of mRNA levels by in vitro translation and hybridization analyses with cloned DNA sequences for photosynthetic proteins, we have found there are rather minor effects of nitrogen deficiency on nuclear or chloroplast gene transcription. Maturation of a transcript of the nuclear-encoded small subunit of ribulose 1,5-bisphosphate carboxylase is inhibited in nitrogen-deficient cells and causes accumulation of large amounts of mRNA precursors. Most of the effects of nitrogen deficiency on photosynthetic proteins appear to result from posttranscriptional regulatory processes: light-harvesting protein synthesis may be sustained but their import into chloroplasts or translocation to photosynthetic membranes is impaired. Nitrogen-deficient cells lack violaxanthin, a pigment that is essential for the structure, function and biogenesis of the major antenna complexes. The absence of this pigment may be a causative factor for the deficiency of light harvesting complexes. Finally, the accumulation of massive amounts of starch and triglycerides in nitrogen-limited cells indicate there are some genes whose maximal expression is dependent upon nitrogen-limiting conditions. 10 refs.

Method for optical 15N analysis of small amounts of nitrogen gas released from an automatic nitrogen analyzer

International Nuclear Information System (INIS)

Arima, Yasuhiro

1981-01-01

A method of optical 15 N analysis is proposed for application to small amounts of nitrogen gas released from an automatic nitrogen analyzer (model ANA-1300, Carlo Erba, Milano) subjected to certain set modifications. The ANA-1300 was combined with a vacuum line attached by a molecular sieve 13X column. The nitrogen gas released from the ANA-1300 was introduced with a carrier gas of helium into the molecular sieve column which was pre-evacuated at 10 -4 Torr and cooled with outer liquid nitrogen. After removal of the helium by evacuation, the nitrogen gas fixed on the molecular sieve was released by warming the column, and then, it was sealed into pre-evacuated pyrex glass tubes at 4.5 - 5.0 Torr. In the preparation of discharge tubes, contamination of unlabelled nitrogen occurred from the carrier gas of standard grade helium, and the relative lowering of the 15 N value by it was estimated to be less than 1% when over 700 μg nitrogen was charged on the ANA-1300; when 200 μg nitrogen was charged, it was about 3.5%. However, the effect of the contamination could be corrected for by knowing the amount of contaminant nitrogen. In the analysis of plant materials by the proposed method, the coefficient of variation was less than 2%, and no significant difference was observed between results given by the present method and by the ordinary method in which samples were directly pyrolyzed in the discharge tubes by the Dumas method. The present method revealed about 1.5 μg of cross-contaminated nitrogen and was applicable to more than 200 μg of sample nitrogen. (author)

Nitrogen uptake and assimilation by corn roots

International Nuclear Information System (INIS)

Yoneyama, Tadakatsu; Akiyama, Yoko; Kumazawa, Kikuo

1977-01-01

The site of nitrogen uptake in the apical root zone of corn was experimentally investigated. Two experiments were performed. The one is to see the assimilation of nitrate and ammonium and the effects of low temperature on it. The 4-day-old roots were treated with 15 N-labelled inorganic nitrogen of 20 ppm N in 5 x 10 -4 M CaSO 4 solution at 30 deg. C and 0 deg. C. The other is to see the nitrogen uptake at apical root zone and the utilization of newly absorbed nitrogen at the root top. The 4-day-old roots were transferred into 5 x 10 -4 M CaSO 4 solution containing 15 N-labelled ammonium nitrate of 40 ppm N. As a result, the effect of low temperature on the nitrogen uptake appeared to be more drastic in the case of nitrate than ammonium. The 15 N content of amino acids indicates that ammonium is assimilated into amino acids even at 0 deg. C, but nitrate is not. The ammonium nitrogen seemed to be absorbed at both cell dividing and elongating zones. On the other hand, nitrate nitrogen seemed to be strongly absorbed at cell elongating zone. The nitrogen in the apical part may be supplied not only by direct absorption but also by translocation from the basal part. The clear difference was found in the utilization of nitrate and ammonium nitrogen at the root top when the root was elongating. This may be due to the difference of assimilation products of inorganic nitrogen. Newly absorbed ammonium nitrogen is more utilizable for the growth of root top than nitrate nitrogen. (Iwakiri, K.)

Eighth international congress on nitrogen fixation. Final program

Energy Technology Data Exchange (ETDEWEB)

1990-12-31

This volume contains the proceedings of the Eighth International Congress on Nitrogen Fixation held May 20--26, 1990 in Knoxville, Tennessee. The volume contains abstracts of individual presentations. Sessions were entitled Recent Advances in the Chemistry of Nitrogen Fixation, Plant-microbe Interactions, Limiting Factors of Nitrogen Fixation, Nitrogen Fixation and the Environment, Bacterial Systems, Nitrogen Fixation in Agriculture and Industry, Plant Function, and Nitrogen Fixation and Evolution.

Anaerobic Nitrogen Fixers on Mars

Science.gov (United States)

Lewis, B. G.

2000-07-01

The conversion of atmospheric nitrogen gas to the protein of living systems is an amazing process of nature. The first step in the process is biological nitrogen fixation, the transformation of N2 to NH3. The phenomenon is crucial for feeding the billions of our species on Earth. On Mars, the same process may allow us to discover how life can adapt to a hostile environment, and render it habitable. Hostile environments also exist on Earth. For example, nothing grows in coal refuse piles due to the oxidation of pyrite and marcasite to sulfuric acid. Yet, when the acidity is neutralized, alfalfa and soybean plants develop root nodules typical of symbiotic nitrogen fixation with Rhizobium species possibly living in the pyritic material. When split open, these nodules exhibited the pinkish color of leghemoglobin, a protein in the nodule protecting the active nitrogen-fixing enzyme nitrogenase against the toxic effects of oxygen. Although we have not yet obtained direct evidence of nitrogenase activity in these nodules (reduction of acetylene to ethylene, for example), these findings suggested the possibility that nitrogen fixation was taking place in this hostile, non-soil material. This immediately raises the possibility that freeliving anaerobic bacteria which fix atmospheric nitrogen on Earth, could do the same on Mars.

Quantitative determination of heavy nitrogen by spectroscopy

International Nuclear Information System (INIS)

Kumazawa, Kikuo

1974-01-01

Explanation is made on the merits of the determination with heavy nitrogen, the principle and apparatus used for the determination, the method of production of discharge tubes, and the application of the method to several special cases. The spectra belonging to the 2nd positive system are used for the analysis of heavy nitrogen by emission spectroscopy. The spectra near 2980 A are used most often. The bandheads utilizable for the determination are 2976.8 for 14 N 2 , 2982.9 for 14 N 15 N, and 2988.6 A for 15 N 2 , respectively. The sample must be sealed in a discharge tube as nitrogen gas, at first. Mixing of impurities lowers the sensitivity of the determination. The gas pressure is adjusted 10 1-6 Torr. The preparation of gaseous nitrogen is made by either the Rittenberg or the Dumas method. When the amount of a given sample is more than 50 mg, and nitrogen is present as ammonium salt, NH 3 is converted to nitrogen by the reaction with sodium hypobromite. When nitrogen is not present as ammonium salt, Dumas' method is adopted. The amount of heavy nitrogen in the aminoacid separated by thin layer chromatography with silica gel was successfully determined by this method. Simultaneous determination of heavy nitrogen and total nitrogen was also possible by this method. (Fukutomi, T.)

Temperature sensitivity of nitrogen productivity

OpenAIRE

Ladanai, Svetlana; Ågren, Göran

2002-01-01

Environmental conditions control physiological processes in plants and thus their growth. The predicted global warming is expected to accelerate tree growth. However, the growth response is a complex function of several processes. To circumvent this problem we have used the nitrogen productivity (dry matter production per unit of nitrogen in the plant), which is an aggregate parameter. Data on needle dry matter, production, and nitrogen content in needles of Scots pine (Pinus sylvestris) from...

Effect of Nitrogen Foliar Application on Canola Yield (Brassica napus L. and Nitrogen Efficiency across Different Sowing Dates

Directory of Open Access Journals (Sweden)

S Doori

2016-12-01

Full Text Available Introduction Between oil seeds, from the quality, quantity and nutrition index point of view, canola has the top level . Because of the solubility of N fertilizers, the time of urea application, is very important and one of the main reasons of the reduction in N application efficiency is utilization of urea in an inappropriate time. By precisely foliar application of nitrogen, the efficiency of nitrogen transformation to the grain will be very high because in this method the leaf is considered the main organ of nitrogen uptake and a low amount of absorbed nitrogen was transferred to the root and entered the soil. The more division of N application in growth stages and in accordance with plant need and foliar application result in increasing nitrogen use efficiency. The delay in sowing will result in the reduction of yield and this is due to low LAI, and thus low radiation absorb in vegetable phase and shorter reproductive phase with high temperature in flowering and subsequent stages that result in low prolific silique and make disorder in transferring stored material to grain. In this experiment using N foliar application to decrease the adverse effect of delay in sowing is objective. Materials and Methods The experiment was conducted in 2013-2014 in Ramin Agriculture and Natural Resource University of Khuzestan. Experiment was conducted as split plots in a randomized complete blocks design with three replications. In this experiment sowing date]optimum sowing (27 November, 17 December and late sowing (30 December [were assigned to main plots and several time of N-foliar application with 5 percent density from urea (20 liter per ha, ]TO (control, T1 (foliar N application in rosette stage, T2 (foliar N application in budding stage, T3 (foliar N application in flowering stage[ were placed in sub-plots in randomized way. Fertilizing was based on the results of soil examination. Therefore, 162 kg ha-1 of pure nitrogen (from resource urea in the way

Climate variability and nitrogen rate interactions affecting corn nitrogen use efficiency in Alabama

Science.gov (United States)

Nitrogen (N) fertilization is an important practice to increase yield; however, plant–soil interactions to in-season changes in climatic conditions result on site-specific responses of corn to nitrogen rates. The objective of this study was to evaluate the effect of different climatic conditions and...

Fate of fertilizer nitrogen in flooded rice soil - I. Leaching losses of nitrogen

International Nuclear Information System (INIS)

Daftardar, S.Y.; Deb, D.L.; Datta, N.P.

1979-01-01

A greenhouse experiment on rice (Oryza sativa L. cv IR 22) was conducted under flooded conditions using CO( 15 NH 2 ) 2 , 15 NH 4 NO 3 and NH 4 ( 15 NO 3 ) to study the leaching loss of added fertilizer nitrogen in two typical rice soils. The loss of nitrogen was in the order: NO 3 -N (4 to 25.6 percent) > amide-N (1.2 to 16.2 percent) > NH 4 -N (0.07 to 0.3 percent). The basal applied urea was lost by percolation in the first month while the basal applied NO 3 -N was lost in the first 8 days. Leaching loss did not occur after split application of fertilizer nitrogen at primordial initiation stage. The loss of nitrogen in kaolinitic Dapoli clay loam soil was about 2.5 to 4.5 times more than that in montmorillonitic Karjat sandy loam soil. Cropping reduced the percolation loss of N by 40 to 60 percent. (auth.)

[Assimilation of biological nitrogen by European beaver].

Science.gov (United States)

Vecherskiĭ, M V; Naumova, E I; Kostina, N V; Umarov, M M

2009-01-01

Nitrogenase activity, the abundance of diazotrophic bacteria, the structure and functional characteristics of the complex of microorganisms, and the content of nitrogen and carbon were determined in the contents of the gastrointestinal tract of the European beaver. A high nitrogen-fixing activity in the large intestine correlated with an increase in nitrogen content in the chyme upon its transfer over the gastrointestinal tract. It is assumed that microbial nitrogen fixation plays a major role in nitrogen nutrition of the European beaver.

Fluxes of oxidised and reduced nitrogen above a mixed coniferous forest exposed to various nitrogen emission sources

Energy Technology Data Exchange (ETDEWEB)

Neirynck, J. [Research Institute for Nature and Forest, Gaverstraat 4, B-9500 Geraardsbergen (Belgium)]. E-mail: johan.neirynck@inbo.be; Kowalski, A.S. [Departamento de Fisica Aplicida, Facultad de Ciencias, Universidad de Granada, Calle Fuentenueva, SP-18071 Granada (Spain); Carrara, A. [Fundacion CEAM, Parque Technologico, Calle Charles H. Darwin 14, SP-46980 Paterna (Valencia) (Spain); Genouw, G. [Research Institute for Nature and Forest, Gaverstraat 4, B-9500 Geraardsbergen (Belgium); Berghmans, P. [Flemish Institute for Technological Research, Boeretang 200, B-2400 Mol (Belgium); Ceulemans, R. [Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk (Antwerp) (Belgium)

2007-09-15

Concentrations of nitrogen gases (NH{sub 3}, NO{sub 2}, NO, HONO and HNO{sub 3}) and particles (pNH{sub 4} and pNO{sub 3}) were measured over a mixed coniferous forest impacted by high nitrogen loads. Nitrogen dioxide (NO{sub 2}) represented the main nitrogen form, followed by nitric oxide (NO) and ammonia (NH{sub 3}). A combination of gradient method (NH{sub 3} and NO {sub x} ) and resistance modelling techniques (HNO{sub 3}, HONO, pNH{sub 4} and pNO{sub 3}) was used to calculate dry deposition of nitrogen compounds. Net flux of NH{sub 3} amounted to -64 ng N m{sup -2} s{sup -1} over the measuring period. Net fluxes of NO {sub x} were upward (8.5 ng N m{sup -2} s{sup -1}) with highest emission in the morning. Fluxes of other gases or aerosols substantially contributed to dry deposition. Total nitrogen deposition was estimated at -48 kg N ha{sup -1} yr{sup -1} and consisted for almost 80% of NH {sub x} . Comparison of throughfall nitrogen with total deposition suggested substantial uptake of reduced N ({+-}15 kg N ha{sup -1} yr{sup -1}) within the canopy. - Reduced nitrogen was found to be the main contributor to total deposition which was predominantly governed by dry deposition.

Geochemical isotope compartment model of the nitrogen cycle

International Nuclear Information System (INIS)

Weise, G.; Wetzel, K.; Stiehl, G.

1981-01-01

A model of the global cycle of nitrogen and its isotopes is described. It takes into account geochemical reservoirs (nitrogen in magmatic metamorphic, and sedimentary rocks and in the atmosphere) and the nitrogen exchange between magmatic rocks and the outer mantle, the transition of nitrogen exchange between sedimentary rocks and the atmosphere. With the aid of the mathematical formalisms of the compartment theory and on the basis of all available delta 11 N values assumptions regarding the isotope effects in forming these nitrogen fluxes data have been obtained on the degree of the nitrogen exchange between the earth crust and the outer mantle and on other nitrogen fluxes characterizing the global nitrogen cycle. (author)

Studies on nitrogen metabolism of soybean plants, (4)

International Nuclear Information System (INIS)

Kato, Yasumasa; Kitada, Subaru

1979-01-01

Nitrogen that came from cotyledons and nitrogen ( 15 N) pulse-fed at 5 different times during the growth of young soybean plants were studied for 33-days after germination. Cotyledons furnished nitrogen to primary leaves, stems, and roots for the first 8 days, but thereafter principally to 1 st and 2 nd trifoliate leaves. Redistribution of the cotyledon-derived nitrogen from primary leaves commenced from the 14 th day after germination when their total nitrogen was still increasing. At the end of the experiment, the cotyledon-derived nitrogen was distributed approximately uniformly among 6 expanded leaves, and very small amount was found in 3 immature leaves. It was shown that soybean leaves took up 15 N (via roots) throughout the entire period of their life, and from their near-mature stage onwards, uptake and redistribution of nitrogen were observed simultaneously. Thus, the nitrogen in mature leaves was partially being renewed constantly. Considering this fact, the nitrogen supplying capacity of soybean leaves was estimated to be about two times as large as that estimated conventionally from the net loss of nitrogen during their senescence. The turnover of leaf nitrogen was closely related to the turnover of leaf protein. Influx of nitrogen was invariably accompanied by the simultaneous synthesis of leaf protein, and conversely, efflux by the simultaneous breakdown of leaf protein. Sink removal (topping treatment) prevented the breakdown of leaf protein (as measured from the rate of release of label after the pulse feeding) as well as the export of nitrogen from the leaves. The nitrogen supplying function of soybean leaves was discussed in relation to the nitrogen and protein turnover of leaves. (Kaihara, S.)

The Bevatron liquid nitrogen circulation system

International Nuclear Information System (INIS)

Hunt, D.; Stover, G.

1987-03-01

A nitrogen liquefier and computer controlled valving system have been added to the Bevatron cryoliner vacuum system to cut operating costs by reducing liquid nitrogen consumption. The computer and interface electronic systems, which control the temperatures of twenty-eight liquid nitrogen circuits, have been chosen and designed to operate in the Bevatron's pulsating magnetic field. The nitrogen exhaust is routed back to a liquefier, of about five kilowatt capacity, liquefied, and rerouted through the cooling circuits. A description of the system and operating results are presented

Comparative effects of climate on ecosystem nitrogen and soil biogeochemistry in U.S. national parks. FY 2001 Annual Report (Res. Rept. No. 94)

Science.gov (United States)

Stottlemyer, R.; Edmonds, R.; Scherbarth, L.; Urbanczyk, K.; Van Miegroet, H.; Zak, J.

2002-01-01

In 1998, the USGS Global Change program funded research for a network of Long-Term Reference Ecosystems initially established in national parks and funded by the National Park Service. The network included Noland Divide, Great Smoky Mountains National Park, Tennessee; Pine Canyon, Big Ben National park, Texas; West Twin Creek, Olympic National Park, Washingtona?? Wallace Lake, Isle Royale National Park, Michigan; and the Asik watershed, Noatak National Preserve, Alaska. The watershed ecosystem model was used since this approach permits additional statistical power in detection of trends among variables, and the watershed in increasingly a land unit used in resource management and planning. The ecosystems represent a major fraction of lands administered by the National Park Service, and were chosen generally for the contrasts among sites. For example, tow of the site, Noland and West Twin, are characterized by high precipitation amounts, but Noland receives some of the highest atmospheric nitrogen (N) inputs in North America. In contrast, Pine Canyon and Asik are warm and cold desert sites respectively. The Asik watershed receives treeline) of the boreal biome in the North America while Wallace is at the southern ecotone between boreal and northern hardwoods. The research goal for these sites is to gain a basic understanding of ecosystem structure and function, and the response to global change especially atmospheric inputs and climate.

The Global Nitrogen Cycle

Science.gov (United States)

Galloway, J. N.

2003-12-01

Once upon a time nitrogen did not exist. Today it does. In the intervening time the universe was formed, nitrogen was created, the Earth came into existence, and its atmosphere and oceans were formed! In this analysis of the Earth's nitrogen cycle, I start with an overview of these important events relative to nitrogen and then move on to the more traditional analysis of the nitrogen cycle itself and the role of humans in its alteration.The universe is ˜15 Gyr old. Even after its formation, there was still a period when nitrogen did not exist. It took ˜300 thousand years after the big bang for the Universe to cool enough to create atoms; hydrogen and helium formed first. Nitrogen was formed in the stars through the process of nucleosynthesis. When a star's helium mass becomes great enough to reach the necessary pressure and temperature, helium begins to fuse into still heavier elements, including nitrogen.Approximately 10 Gyr elapsed before Earth was formed (˜4.5 Ga (billion years ago)) by the accumulation of pre-assembled materials in a multistage process. Assuming that N2 was the predominate nitrogen species in these materials and given that the temperature of space is -270 °C, N2 was probably a solid when the Earth was formed since its boiling point (b.p.) and melting point (m.p.) are -196 °C and -210 °C, respectively. Towards the end of the accumulation period, temperatures were probably high enough for significant melting of some of the accumulated material. The volcanic gases emitted by the resulting volcanism strongly influenced the surface environment. Nitrogen was converted from a solid to a gas and emitted as N2. Carbon and sulfur were probably emitted as CO and H2S (Holland, 1984). N2 is still the most common nitrogen volcanic gas emitted today at a rate of ˜2 TgN yr-1 (Jaffee, 1992).Once emitted, the gases either remained in the atmosphere or were deposited to the Earth's surface, thus continuing the process of biogeochemical cycling. The rate of

Nitrogen recycling from fuel-extracted algal biomass: residuals as the sole nitrogen source for culturing Scenedesmus acutus.

Science.gov (United States)

Gu, Huiya; Nagle, Nick; Pienkos, Philip T; Posewitz, Matthew C

2015-05-01

In this study, the reuse of nitrogen from fuel-extracted algal residues was investigated. The alga Scenedesmus acutus was found to be able to assimilate nitrogen contained in amino acids, yeast extracts, and proteinaceous alga residuals. Moreover, these alternative nitrogen resources could replace nitrate in culturing media. The ability of S. acutus to utilize the nitrogen remaining in processed algal biomass was unique among the promising biofuel strains tested. This alga was leveraged in a recycling approach where nitrogen is recovered from algal biomass residuals that remain after lipids are extracted and carbohydrates are fermented to ethanol. The protein-rich residuals not only provided an effective nitrogen resource, but also contributed to a carbon "heterotrophic boost" in subsequent culturing, improving overall biomass and lipid yields relative to the control medium with only nitrate. Prior treatment of the algal residues with Diaion HP20 resin was required to remove compounds inhibitory to algal growth. Copyright © 2014 Elsevier Ltd. All rights reserved.

21 CFR 862.1770 - Urea nitrogen test system.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Urea nitrogen test system. 862.1770 Section 862....1770 Urea nitrogen test system. (a) Identification. A urea nitrogen test system is a device intended to measure urea nitrogen (an end-product of nitrogen metabolism) in whole blood, serum, plasma, and urine...

Biexciton emission from single isoelectronic traps formed by nitrogen-nitrogen pairs in GaAs

Energy Technology Data Exchange (ETDEWEB)

Takamiya, Kengo; Fukushima, Toshiyuki; Yagi, Shuhei; Hijikata, Yasuto; Yaguchi, Hiroyuki [Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku , Saitama 338-8570 (Japan); Mochizuki, Toshimitsu; Yoshita, Masahiro; Akiyama, Hidefumi [Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Kuboya, Shigeyuki; Onabe, Kentaro [Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Katayama, Ryuji [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

2013-12-04

We have studied photoluminescence (PL) from individual isoelectronic traps formed by nitrogen-nitrogen (NN) pairs in GaAs. Sharp emission lines due to exciton and biexciton were observed from individual isoelectronic traps in nitrogen atomic-layer doped (ALD) GaAs. The binding energy of biexciton bound to individual isoelectronic traps was approximately 8 meV. Both the exciton and biexciton luminescence lines show completely random polarization and no fine-structure splitting. These results are desirable to the application to the quantum cryptography used in the field of quantum information technology.

Availability of residual nitrogen from fertilizers in soil

International Nuclear Information System (INIS)

Jakovljevic, M.; Filipovic, R.; Petrovic, M.

1983-01-01

The plant availability of residual fertilizer nitrogen for the next crop was studied in chernozem and pseudogley soils. Release of nitrogen was examined after incubation at 3 and 30 0 C. It was found that the use of increased doses of nitrogen fertilizer (ammonium nitrate) led to an increased release of residual fertilizer nitrogen into plant available forms. The release of this nitrogen fraction was 5-10 times faster in comparison with the remaining soil nitrogen. (author)

Availability of residual nitrogen from fertilizers in soil

Energy Technology Data Exchange (ETDEWEB)

Jakovljevic, M.; Filipovic, R.; Petrovic, M. (Institut za Primeni Nuklearne Energije u Poljoprivedri, Veterinarstvu i Sumarstvu, Zemun (Yugoslavia))

1983-05-01

The plant availability of residual fertilizer nitrogen for the next crop was studied in chernozem and pseudogley soils. Release of nitrogen was examined after incubation at 3 and 30/sup 0/C. It was found that the use of increased doses of nitrogen fertilizer (ammonium nitrate) led to an increased release of residual fertilizer nitrogen into plant available forms. The release of this nitrogen fraction was 5-10 times faster in comparison with the remaining soil nitrogen.

Energy transfer in Anabaena variabilis filaments adapted to nitrogen-depleted and nitrogen-enriched conditions studied by time-resolved fluorescence.

Science.gov (United States)

Onishi, Aya; Aikawa, Shimpei; Kondo, Akihiko; Akimoto, Seiji

2017-09-01

Nitrogen is among the most important nutritious elements for photosynthetic organisms such as plants, algae, and cyanobacteria. Therefore, nitrogen depletion severely compromises the growth, development, and photosynthesis of these organisms. To preserve their integrity under nitrogen-depleted conditions, filamentous nitrogen-fixing cyanobacteria reduce atmospheric nitrogen to ammonia, and self-adapt by regulating their light-harvesting and excitation energy-transfer processes. To investigate the changes in the primary processes of photosynthesis, we measured the steady-state absorption and fluorescence spectra and time-resolved fluorescence spectra (TRFS) of whole filaments of the nitrogen-fixing cyanobacterium Anabaena variabilis at 77 K. The filaments were grown in standard and nitrogen-free media for 6 months. The TRFS were measured with a picosecond time-correlated single photon counting system. Despite the phycobilisome degradation, the energy-transfer paths within phycobilisome and from phycobilisome to both photosystems were maintained. However, the energy transfer from photosystem II to photosystem I was suppressed and a specific red chlorophyll band appeared under the nitrogen-depleted condition.

Nitrogen gas supply device in nuclear power plant

International Nuclear Information System (INIS)

Nishino, Masami

1991-01-01

The present invention concerns a nitrogen gas supply device in a nuclear power plant for supplying nitrogen gases to a reactor container and equipments working with the nitrogen gas as the load. A liquid nitrogen storage pool is disposed to a concrete nuclear buildings and has a two-vessel structure of inner and outer vessels, in which heat insulators are disposed between the inner and the outer vessels. Further, the nitrogen gas supply mechanism is disposed in an evaporation chamber disposed in adjacent with the liquid nitrogen storage pool in the reator building. Accordingly, since liquid nitrogen is stored in the liquid nitrogen storage pool having a structure surrounded by concrete walls, direct sunlight is completely interrupted, thereby enabling to prevent the heat caused by the direct sunlight from conducting to the liquid nitrogen. Further, since the outer vessel is not exposed to the surrounding atmosphere, heat conduction rate relative to the external air is small. This can reduce the amount of liquid nitrogen released to the atmospheric air due to natural evaporation. (I.N.)

Hybrid process for nitrogen oxides reduction

Energy Technology Data Exchange (ETDEWEB)

Epperly, W.R.; Sprague, B.N.

1991-09-10

This patent describes a process for reducing the nitrogen oxide concentration in the effluent from the combustion of a carbonaceous fuel. It comprises introducing into the effluent a first treatment agent comprising a nitrogenous composition selected from the group consisting of urea, ammonia, hexamethylenetetramine, ammonium salts of organic acids, 5- or 6-membered heterocyclic hydrocarbons having at least one cyclic nitrogen, hydroxy amino hydrocarbons, NH{sub 4}-lignosulfonate, fur-furylamine, tetrahydrofurylamine, hexamethylenediamine, barbituric acid, guanidine, guanidine carbonate, biguanidine, guanylurea sulfate, melamine, dicyandiamide, biuret, 1.1{prime}-azobisformamide, methylol urea, methylol urea-urea condensation product, dimethylol urea, methyl urea, dimethyl urea, calcium cyanamide, and mixtures thereof under conditions effective to reduce the nitrogen oxides concentration and ensure the presence of ammonia in the effluent; introducing into the effluent a second treatment agent comprising an oxygenated hydrocarbon at an effluent temperature of about 500{degrees} F. to about 1600{degrees} F. under conditions effective to oxidize nitric oxide in the effluent to nitrogen dioxide and ensure the presence of ammonia at a weight ratio of ammonia to nitrogen dioxide of about 1:5 to about 5:1; and contacting the effluent with an aqueous scrubbing solution having a pH of 12 or lower under conditions effective to cause nitrogen dioxide to be absorbed therein.

Influence of the compound effect between nitrogen and zinc on the resource of nitrogen of herbage in mixed and pure culture

International Nuclear Information System (INIS)

He Zhongjun; Hua Luo

2002-01-01

Under pot culture, the influence of compound effect between nitrogen and zinc on the resource of nitrogen of ryegrass in mono-culture and ryegrass/clover in mixture were studied on yellow brown earth which collected from sub-tropic mountain sward of southern China. The result showed as follows: (1) The percentage of nitrogen derived from atmosphere (% Ndfa) was decreased by nitrogen application in early growth stage and suitable amount of nitrogen application increased it in later growth stage. The % Ndfa of white clover in mixture was the highest with 6 mg/kg zinc application in all nitrogen levels. The transfer of fixed nitrogen by white clover to ryegrass was decreased by nitrogen application and increased by low amount of zinc application. (2) The percentage of nitrogen derived from fertilizer (% Ndff) was significantly increased by nitrogen application, of which the treatments with 6-20 mg/kg zinc application was higher than other zinc application treatments on ryegrass in monoculture, and the treatments with 6-20 mg/kg zinc application on white clover/ryegrass in mixture was lower than other zinc treatments at the range from 30 to 90 mg/kg nitrogen application. (3) The percentage of nitrogen derived from soil (% Ndfs) of ryegrass both in pure and in mixture was significantly decreased as the increasing of the levels of nitrogen application, of which ryegrass in mono-culture was not obviously influenced by zinc application, and ryegrass/clover in mixture was decreased by 6-20 mg/kg zinc application under all nitrogen levels

Options for including nitrogen management in climate policy

International Nuclear Information System (INIS)

Erisman, J.W.

2010-12-01

The outline of the presentation is as follows: Climate change and nitrogen; Nitrogen and climate interlinkages; Options for nitrogen management; Report, workshop and IPCC; and Conclusions. The concluding remarks are: Fertilizing the biosphere with reactive nitrogen compounds lead to ecosystem, health, water and climate impacts; Nitrogen deposition can lead to additional carbon sequestration and to impacts on biodiversity and ecosystem services; Nitrogen addition to the biosphere might have a net cooling effect of 1 W/m 2 ; Life Cycle Analysis is needed to show the full impact; and Nitrogen management is essential for the environment and can have a positive effect on the net GHG exchange.

Transferencias matrimoniales en el Occidente islámico medieval: las joyas como regalo de boda

Directory of Open Access Journals (Sweden)

Zomeño Rodríguez, Amalia

1996-12-01

Full Text Available The paper analyzes several legal cases concerning donations and loans of jewels in the context of the Islamic marriage in the Middle Ages. The bride receives gifts of jewels from her would-be husband that form part of her property thereafter. The father also offers a substantial contribution of jewels to her daughter, yet often this is given with the expectation of their being returned subsequent to the marriage ceremony. Two of the gifts studied here consist of a strand of pearls, gold earrings, and silver anklets. They are jewels described already in ethnographic studies as part of the adornment that the bride traditionally wears at weddings in the contemporary Maghreb.Este trabajo analiza varios casos en los que se reflejan problemas legales surgidos en torno a una donación o préstamo de joyas, dentro del contexto matrimonial islámico medieval. La novia, de hecho, recibe varios regalos que contienen joyas de manos de su marido, que formarán parte de sus propiedades después de su boda. Por otro lado, el padre entrega también un conjunto importante de joyas a su hija, pero es frecuente que le sean prestadas con la intención de que se le devuelvan posteriormente. Dos de los regalos que aquí se estudian contienen un sartal de aljófar, unos zarcillos de oro y unas ajorcas de plata. Todas ellas son joyas que han sido ya descritas en los trabajos de etnografía como parte de los adornos que la novia lleva tradicionalmente en su boda en el Magreb actual.

Nitrogen recycling through the gut and the nitrogen economy of ruminants: An asynchronous symbiosis

DEFF Research Database (Denmark)

Reynolds, C K; Kristensen, Niels Bastian

2007-01-01

The extensive development of the ruminant forestomach sets apart their nitrogen (N) economy from that of nonruminants in a number of respects. Extensive pre-gastric fermentation alters the profile of protein reaching the small intestine, largely through the transformation of nitrogenous compounds...

Impacts of tropical cyclones on hydrochemistry of a subtropical forest

Directory of Open Access Journals (Sweden)

C. T. Chang

2013-10-01

Full Text Available Tropical cyclones (typhoons/hurricanes have major impacts on the biogeochemistry of forest ecosystems, but the stochastic nature and the long intervals between storms means that there are limited data on their effects. We characterised the impacts of 14 typhoons over six years on hydrochemistry of a subtropical forest plantation in Taiwan, a region experiencing frequent typhoons. Typhoons contributed 1/3 of the annual rainfall on average, but ranged from 4 to 55%. The stochastic nature of annual typhoon related precipitation poses a challenge with respect to managing the impacts of these extreme events. This challenge is exacerbated by the fact that typhoon-related rainfall is not significantly correlated with wind velocity, the current focus of weather forecasts. Thus, little advance warning is provided for the hydrological impacts of these storms. The typhoons we studied contributed approximately one third of the annual input and output of most nutrients (except nitrogen during an average 9.5 day yr−1 period, resulting in nutrient input/output rates an order of magnitude greater than during non-typhoon months. Nitrate output balanced input during the non-typhoon period, but during the typhoon period an average of 10 kg ha−1 yr−1 nitrate was lost. Streamwater chemistry exhibited similarly high variability during typhoon and non-typhoon periods and returned to pre-typhoon levels one to three weeks following each typhoon. The streamwater chemistry appears to be very resilient in response to typhoons, resulting in minimal loss of nutrients.

Substantial nitrogen pollution embedded in international trade

Science.gov (United States)

Oita, Azusa; Malik, Arunima; Kanemoto, Keiichiro; Geschke, Arne; Nishijima, Shota; Lenzen, Manfred

2016-02-01

Anthropogenic emissions of reactive nitrogen to the atmosphere and water bodies can damage human health and ecosystems. As a measure of a nation’s contribution to this potential damage, a country’s nitrogen footprint has been defined as the quantity of reactive nitrogen emitted during the production, consumption and transportation of commodities consumed within that country, whether those commodities are produced domestically or internationally. Here we use global emissions databases, a global nitrogen cycle model, and a global input-output database of domestic and international trade to calculate the nitrogen footprints for 188 countries as the sum of emissions of ammonia, nitrogen oxides and nitrous oxide to the atmosphere, and of nitrogen potentially exportable to water bodies. Per-capita footprints range from under 7 kg N yr-1 in some developing countries to over 100 kg N yr-1 in some wealthy nations. Consumption in China, India, the United States and Brazil is responsible for 46% of global emissions. Roughly a quarter of the global nitrogen footprint is from commodities that were traded across country borders. The main net exporters have significant agricultural, food and textile exports, and are often developing countries, whereas important net importers are almost exclusively developed economies. We conclude that substantial local nitrogen pollution is driven by demand from consumers in other countries.

Nitrogen-doped graphene: effect of graphite oxide precursors and nitrogen content on the electrochemical sensing properties.

Science.gov (United States)

Megawati, Monica; Chua, Chun Kiang; Sofer, Zdenek; Klímová, Kateřina; Pumera, Martin

2017-06-21

Graphene, produced via chemical methods, has been widely applied for electrochemical sensing due to its structural and electrochemical properties as well as its ease of production in large quantity. While nitrogen-doped graphenes are widely studied materials, the literature showing an effect of graphene oxide preparation methods on nitrogen quantity and chemical states as well as on defects and, in turn, on electrochemical sensing is non-existent. In this study, the properties of nitrogen-doped graphene materials, prepared via hydrothermal synthesis using graphite oxide produced by various classical methods using permanganate or chlorate oxidants Staudenmaier, Hummers, Hofmann and Brodie oxidation methods, were studied; the resulting nitrogen-doped graphene oxides were labeled as ST-GO, HU-GO, HO-GO and BR-GO, respectively. The electrochemical oxidation of biomolecules, such as ascorbic acid, uric acid, dopamine, nicotinamide adenine nucleotide and DNA free bases, was carried out using cyclic voltammetry and differential pulse voltammetry techniques. The nitrogen content in doped graphene oxides increased in the order ST-GO graphene followed this trend, as shown in the cyclic voltammograms. This is a very important finding that provides insight into the electrocatalytic effect of N-doped graphene. The nitrogen-doped graphene materials exhibited improved sensitivity over bare glassy carbon for ascorbic acid, uric acid and dopamine detection. These studies will enhance our understanding of the effects of graphite oxide precursors on the electrochemical sensing properties of nitrogen-doped graphene materials.

Chitin: 'Forgotten' Source of Nitrogen: From Modern Chitin to Thermally Mature Kerogen: Lessons from Nitrogen Isotope Ratios

Science.gov (United States)

Schimmelmann, A.; Wintsch, R.P.; Lewan, M.D.; DeNiro, M.J.

1998-01-01

Chitinous biomass represents a major pool of organic nitrogen in living biota and is likely to have contributed some of the fossil organic nitrogen in kerogen. We review the nitrogen isotope biogeochemistry of chitin and present preliminary results suggesting interaction between kerogen and ammonium during thermal maturation. Modern arthropod chitin may shift its nitrogen isotope ratio by a few per mil depending on the chemical method of chitin preparation, mostly because N-containing non-amino-sugar components in chemically complex chitin cannot be removed quantitatively. Acid hydrolysis of chemically complex chitin and subsequent ion-chromatographic purification of the "deacetylated chitin-monomer" D-glucosamine (in hydrochloride form) provides a chemically well-defined, pure amino-sugar substrate for reproducible, high-precision determination of ??15N values in chitin. ??15N values of chitin exhibited a variability of about one per mil within an individual's exoskeleton. The nitrogen isotope ratio differed between old and new exoskeletons by up to 4 per mil. A strong dietary influence on the ??15N value of chitin is indicated by the observation of increasing ??15N values of chitin from marine crustaceans with increasing trophic level. Partial biodegradation of exoskeletons does not significantly influence ??15N values of remaining, chemically preserved amino sugar in chitin. Diagenesis and increasing thermal maturity of sedimentary organic matter, including chitin-derived nitrogen-rich moieties, result in humic compounds much different from chitin and may significantly change bulk ??15N values. Hydrous pyrolysis of immature source rocks at 330??C in contact with 15N-enriched NH4Cl, under conditions of artificial oil generation, demonstrates the abiogenic incorporation of inorganic nitrogen into carbon-bound nitrogen in kerogen. Not all organic nitrogen in natural, thermally mature kerogen is therefore necessarily derived from original organic matter, but may

Toward a mechanistic modeling of nitrogen limitation for photosynthesis

Science.gov (United States)

Xu, C.; Fisher, R. A.; Travis, B. J.; Wilson, C. J.; McDowell, N. G.

2011-12-01

The nitrogen limitation is an important regulator for vegetation growth and global carbon cycle. Most current ecosystem process models simulate nitrogen effects on photosynthesis based on a prescribed relationship between leaf nitrogen and photosynthesis; however, there is a large amount of variability in this relationship with different light, temperature, nitrogen availability and CO2 conditions, which can affect the reliability of photosynthesis prediction under future climate conditions. To account for the variability in nitrogen-photosynthesis relationship under different environmental conditions, in this study, we developed a mechanistic model of nitrogen limitation for photosynthesis based on nitrogen trade-offs among light absorption, electron transport, carboxylization and carbon sink. Our model shows that strategies of nitrogen storage allocation as determined by tradeoff among growth and persistence is a key factor contributing to the variability in relationship between leaf nitrogen and photosynthesis. Nitrogen fertilization substantially increases the proportion of nitrogen in storage for coniferous trees but much less for deciduous trees, suggesting that coniferous trees allocate more nitrogen toward persistence compared to deciduous trees. The CO2 fertilization will cause lower nitrogen allocation for carboxylization but higher nitrogen allocation for storage, which leads to a weaker relationship between leaf nitrogen and maximum photosynthesis rate. Lower radiation will cause higher nitrogen allocation for light absorption and electron transport but less nitrogen allocation for carboxylyzation and storage, which also leads to weaker relationship between leaf nitrogen and maximum photosynthesis rate. At the same time, lower growing temperature will cause higher nitrogen allocation for carboxylyzation but lower allocation for light absorption, electron transport and storage, which leads to a stronger relationship between leaf nitrogen and maximum

Experimental nitrogen dioxide poisoning in cattle

Energy Technology Data Exchange (ETDEWEB)

Cutlip, R C

1966-01-01

Experimental nitrogen dioxide inhalation has been reported to produce signs and lesions typical of field cases of bovine pulmonary adenomatosis (BPA) as described by Monlux et al, and Seaton. Similar lesions have been produced in mice and guinea pigs. These studies were conducted because of the similarities between silo-filler's disease of man, caused by nitrogen dioxide, and BPA. Since previous studies involved inadequate numbers of cattle, a more critical evaluation of the effects of nitrogen dioxide was needed. This project was designed to study the clinical and pathologic alterations induced in cattle by repeated exposure to nitrogen dioxide gas.

The nitrogen abatement cost in wetlands

International Nuclear Information System (INIS)

Bystroem, Olof

1998-01-01

The costs of abating agricultural nitrogen pollution in wetlands are estimated. By linking costs for construction of wetlands to the denitrification capacity of wetlands, an abatement cost function can be formed. A construction-cost function and a denitrification function for wetlands is estimated empirically. This paper establishes a link between abatement costs and the nitrogen load on wetlands. Since abatement costs fluctuate with nitrogen load, ignoring this link results in incorrect estimates of abatement costs. The results demonstrate that wetlands have the capacity to provide low cost abatement of nitrogen compounds in runoff. For the Kattegatt region in Sweden, marginal abatement costs for wetlands are shown to be lower than costs of land use changing measures, such as extended land under fallow or cultivation of fuel woods, but higher than the marginal costs of reducing nitrogen fertilizer

Is There Synchronicity in Nitrogen Input and Output Fluxes at the Noland Divide Watershed, a Small N-Saturated Forested Catchment in the Great Smoky Mountains National Park?

Directory of Open Access Journals (Sweden)

H. Van Miegroet

2001-01-01

Full Text Available High-elevation red spruce [Picea rubens Sarg.]-Fraser fir [Abies fraseri (Pursh. Poir] forests in the Southern Appalachians currently receive large nitrogen (N inputs via atmospheric deposition (30 kg N ha�1 year�1 but have limited N retention capacity due to a combination of stand age, heavy fir mortality caused by exotic insect infestations, and numerous gaps caused by windfalls and ice storms. This study examined the magnitude and timing of the N fluxes into, through, and out of a small, first-order catchment in the Great Smoky Mountains National Park. It also examined the role of climatic conditions in causing interannual variations in the N output signal. About half of the atmospheric N input was exported annually in the streamwater, primarily as nitrate (NO3-N. While most incoming ammonium (NH4-N was retained in the canopy and the forest floor, the NO3-N fluxes were very dynamic in space as well as in time. There was a clear decoupling between NO3-N input and output fluxes. Atmospheric N input was greatest in the growing season while largest NO3-N losses typically occurred in the dormant season. Also, as water passed through the various catchment compartments, the NO3-N flux declined below the canopy, increased in the upper soil due to internal N mineralization and nitrification, and declined again deeper in the mineral soil due to plant uptake and microbial processing. Temperature control on N production and hydrologic control on NO3-N leaching during the growing season likely caused the observed inter-annual variation in fall peak NO3-N concentrations and N discharge rates in the stream.

Assessment of free-living nitrogen fixing microorganisms for commercial nitrogen fixation. [economic analysis of ammonia production

Science.gov (United States)

Stokes, B. O.; Wallace, C. J.

1978-01-01

Ammonia production by Klebsiella pneumoniae is not economical with present strains and improving nitrogen fixation to its theoretical limits in this organism is not sufficient to achieve economic viability. Because the value of both the hydrogen produced by this organism and the methane value of the carbon source required greatly exceed the value of the ammonia formed, ammonia (fixed nitrogen) should be considered the by-product. The production of hydrogen by KLEBSIELLA or other anaerobic nitrogen fixers should receive additional study, because the activity of nitrogenase offers a significant improvement in hydrogen production. The production of fixed nitrogen in the form of cell mass by Azotobacter is also uneconomical and the methane value of the carbon substrate exceeds the value of the nitrogen fixed. Parametric studies indicate that as efficiencies approach the theoretical limits the economics may become competitive. The use of nif-derepressed microorganisms, particularly blue-green algae, may have significant potential for in situ fertilization in the environment.

Monitoring plant tissue nitrogen isotopes to assess nearshore inputs of nitrogen to Lake Crescent, Olympic National Park, Washington

Science.gov (United States)

Cox, Stephen E.; Moran, Patrick W.; Huffman, Raegan L.; Fradkin, Steven C.

2016-05-31

Mats of filamentous-periphytic algae present in some nearshore areas of Lake Crescent, Olympic National Park, Washington, may indicate early stages of eutrophication from nutrient enrichment of an otherwise highly oligotrophic lake. Natural abundance ratios of stable isotopes of nitrogen (δ15N) measured in plant tissue growing in nearshore areas of the lake indicate that the major source of nitrogen used by these primary producing plants is derived mainly from atmospherically fixed nitrogen in an undeveloped forested ecosystem. Exceptions to this pattern occurred in the Barnes Point area where elevated δ15N ratios indicate that effluent from septic systems also contribute nitrogen to filamentous-periphytic algae growing in the littoral zone of that area. Near the Lyre River outlet of Lake Crescent, the δ15N of filamentous-periphytic algae growing in close proximity to the spawning areas of a unique species of trout show little evidence of elevated δ15N indicating that nitrogen from on-site septic systems is not a substantial source of nitrogen for these plants. The δ15N data corroborate estimates that nitrogen input to Lake Crescent from septic sources is comparatively small relative to input from motor vehicle exhaust and vegetative sources in undeveloped forests, including litterfall, pollen, and symbiotic nitrogen fixation. The seasonal timing of blooms of filamentous-periphytic algal near the lake shoreline is also consistent with nitrogen exported from stands of red alder trees (Alnus rubra). Isotope biomonitoring of filamentous-periphytic algae may be an effective approach to monitoring the littoral zone for nutrient input to Lake Crescent from septic sources.

A facile approach towards increasing the nitrogen-content in nitrogen-doped carbon nanotubes via halogenated catalysts

International Nuclear Information System (INIS)

Ombaka, L.M.; Ndungu, P.G.; Omondi, B.; McGettrick, J.D.; Davies, M.L.; Nyamori, V.O.

2016-01-01

Nitrogen-doped carbon nanotubes (N-CNTs) have been synthesized at 850 °C via a CVD deposition technique by use of three ferrocenyl derivative catalysts, i.e. para-CN, -CF_3 and -Cl substituted-phenyl rings. The synthesized catalysts have been characterized by NMR, IR, HR-MS and XRD. The XRD analysis of the para-CF_3 catalyst indicates that steric factors influence the X-ray structure of 1,1′-ferrocenylphenyldiacrylonitriles. Acetonitrile or pyridine was used as carbon and nitrogen sources to yield mixtures of N-CNTs and carbon spheres (CS). The N-CNTs obtained from the para-CF_3 catalysts, in pyridine, have the highest nitrogen-doping level, show a helical morphology and are less thermally stable compared with those synthesized by use of the para-CN and -Cl as catalyst. This suggests that fluorine heteroatoms enhance nitrogen-doping in N-CNTs and formation of helical-N-CNTs (H-N-CNTs). The para-CF_3 and para-Cl catalysts in acetonitrile yielded iron-filled N-CNTs, indicating that halogens promote encapsulation of iron into the cavity of N-CNT. The use of acetonitrile, as carbon and nitrogen source, with the para-CN and -Cl as catalysts also yielded a mixture of N-CNTs and carbon nanofibres (CNFs), with less abundance of CNFs in the products obtained using para-Cl catalysts. However, para-CF_3 catalyst in acetonitrile gave N-CNTs as the only shaped carbon nanomaterials. - Graphical abstract: Graphical abstract showing the synthesis of N-CNTs using halogenated-ferrocenyl derivatives as catalyst with pyridine or acetonitrile as nitrogen and carbon sources via the chemical vapour deposition technique. - Highlights: • N-CNTs were synthesized from halogenated ferrocenyl catalysts. • Halogenated catalysts promote nitrogen-doping and pyridinic nitrogen in N-CNTs. • Halogenated catalysts facilitate iron filling of N-CNTs.

Genotypic variation of nitrogen use efficiency in Indian mustard

International Nuclear Information System (INIS)

Ahmad, Altaf; Khan, Ishrat; Abrol, Yash P.; Iqbal, Muhammad

2008-01-01

This experiment was conducted to investigate the variation of nitrogen efficiency (NE), nitrogen uptake efficiency (UE), physiological nitrogen use efficiency (PUE) among Indian mustard genotypes, grown under N-insufficient and N-sufficient conditions. Nitrogen efficiency varied from 52.7 to 92.8. Seed yield varied from 1.14 t ha -1 to 3.21 t ha -1 under N-insufficient condition, while 2.14 t ha -1 -3.33 t ha -1 under N-sufficient condition. Physiological basis of this difference was explained in terms of nitrogen uptake efficiency and physiological nitrogen use efficiency, and their relationship with the growth and yield characteristics. While nitrogen uptake efficiency was positively correlated with plant biomass (0.793**), leaf area index (0.664*), and leaf nitrogen content (0.783**), physiological nitrogen use efficiency is positively correlated with photosynthetic rate (0.689**) and yield (0.814**). This study suggests that genotype having high nitrogen uptake efficiency and high physiological nitrogen use efficiency might help in reducing the nitrogen load on soil without any penalty on the yield. - Nitrogen efficient crop plants may help in reducing environmental contamination of nitrate without any penalty on seed yield

Distribution of nitrogen in nature and its separation

International Nuclear Information System (INIS)

Nitzsche, H.M.; Haendel, D.; Muehle, K.

1981-01-01

Proceeding from a survey on nitrogen in the atmosphere, biosphere, hydrosphere, and lithosphere and nitrogen determination methods, a detailed review is given of procedures that allow to transform any nitrogen-containing starting material into molecular nitrogen for mass spectroscopic isotope analysis

Assessing the conservation status of marine habitats: thoughts from a sandflat on the Isles of Scilly

Science.gov (United States)

Warwick, R. M.; Somerfield, P. J.

2015-04-01

Statutory monitoring of the fauna of the 'mudflats and sandflats not covered by seawater at low tide' biotope complex on St Martin's Flats, a part of the Isles of Scilly Complex Special Area of Conservation, was undertaken in 2000, 2004 and 2009. The targets set by Natural England for "characteristic biotopes" were that "composite species, abundance and diversity should not deviate significantly from an established baseline, subject to natural change". The three specified biotopes could not be distinguished, and instead three assemblages were subjectively defined based on sediment surface features. There were statistically significant natural changes in diversity and species composition between years, especially in the association initially characterised by the razor-clam Ensis, and possible reasons for this are discussed. It is suggested that setting fixed local limits on natural variability is almost always impractical. Two possible approaches to distinguishing between natural and anthropogenic changes are suggested; a change in ecological condition as indicated by AMBI scores, and a significant change in average taxonomic distinctness (Δ+) compared with expectation. The determination of species biomasses as well as abundances might also open more possibilities for assessment. The practice of setting objectives for a marine Special Area of Conservation (SAC) feature that include the range and number of biotopes cannot be supported, in view of the difficulty in ascribing assemblages to recognised biotopes. A more realistic definition of species assemblages might best be gained from examination of the species that consistently make a substantial contribution to the Bray-Curtis similarity among samples collected from specific sites.

Nitrogen Compounds in Radiation Chemistry

International Nuclear Information System (INIS)

Sims, H.E.; Dey, G.R.; Vaudey, C.E.; Peaucelle, C.; Boucher, J.L.; Toulhoat, N.; Bererd, N.; Koppenol, W.H.; Janata, E.; Dauvois, V.; Durand, D.; Legand, S.; Roujou, J.L.; Doizi, D.; Dannoux, A.; Lamouroux, C.

2009-01-01

Water radiolysis in presence of N 2 is probably the topic the most controversy in the field of water radiolysis. It still exists a strong discrepancy between the different reports of ammonia formation by water radiolysis in presence of N 2 and moreover in absence of oxygen there is no agreement on the formation or not of nitrogen oxide like NO 2 - and NO 3 -. These discrepancies come from multiple sources: - the complexity of the reaction mechanisms where nitrogen is involved - the experimental difficulties - and, the irradiation conditions. The aim of the workshop is to capitalize the knowledge needed to go further in simulations and understanding the problems caused (or not) by the presence of nitrogen / water in the environment of radioactive materials. Implications are evident in terms of corrosion, understanding of biological systems and atmospheric chemistry under radiation. Topics covered include experimental and theoretical approaches, application and fundamental researches: - Nitrate and Ammonia in radiation chemistry in nuclear cycle; - NOx in biological systems and atmospheric chemistry; - Formation of Nitrogen compounds in Nuclear installations; - Nitrogen in future power plant projects (Gen4, ITER...) and large particle accelerators. This document gathers the transparencies available for 7 of the presentations given at this workshop. These are: - H.E SIMS: 'Radiation Chemistry of Nitrogen Compounds in Nuclear Power Plant'; - G.R. DEY: 'Nitrogen Compounds Formation in the Radiolysis of Aqueous Solutions'; - C.E. VAUDEY et al.: 'Radiolytic corrosion of nuclear graphite studied with the dedicated gas irradiation cell of IPNL'; - J.L. BOUCHER: 'Roles and biosynthesis of NO in eukaryotes and prokaryotes'; - W.H. KOPPENOL: 'Chemistry of NOx'; - E. JANATA: 'Yield of OH in N 2 O saturated aqueous solution'; - V. DAUVOIS: 'Analytical strategy for the study of radiolysis gases'

The problems of high-nitrogen steels production

International Nuclear Information System (INIS)

Svyazhin, A.G.; Kaputkina, L.M.; Efimenko, S.P.

1999-01-01

Analysis of existing technologies of high-nitrogen steel production shows that rational nitrogen content in mass production corresponds to moderate high values. Such steels can be smelted under normal or slightly elevated pressure in steelmaking units, using processes of mass- and special metallurgy. High-nitrogen steels with ''overequilibrium'' nitrogen content are promising, but technology and equipment for production of them are complicated, and production of such steels is therefore limited. (orig.)

A comparison of lead pollution record in Sphagnum peat with known historical Pb emission rates in the British Isles and the Czech Republic

Science.gov (United States)

Novak, Martin; Erel, Yigal; Zemanova, Leona; Bottrell, Simon H.; Adamova, Marie

Vertical Pb concentration gradients and isotope ratios ( 206Pb/ 207Pb, 208Pb/ 207Pb) are reported for five 210Pb-dated Sphagnum peat profiles. The studied peat bogs are in the British Isles (Thorne Moors, England; Mull, Scotland; and Connemara, Eire) and central Europe (Ocean, northern Czech Republic; Rybarenska slat, southern Czech Republic). Both the U.K. and the Czech Republic experienced maximum Pb emissions from Ag-Pb smelting around 1880. Pb emissions from coal burning peaked in 1955 in the U.K. and in the 1980s in the Czech Republic. In both countries, use of alkyl-lead additives to gasoline resulted in large Pb emissions between 1950 and 2000. We hypothesized that peaks in Pb emissions from smelting, coal burning and gasoline burning, respectively, should be mirrored in the peat profiles. However, a more complicated pattern emerged. Maximum annual Pb accumulation rates occurred in 1870 at Ocean, 1940 at Thorne Moors, 1988 at Rybarenska slat, and 1990 at Mull and Connemara. Atmospheric Pb inputs decreased in the order Thorne Moors ≥ Ocean > Rybarenska slat > Mull > Connemara. The Ocean bog was unique in the central European region in that its maximum Pb pollution dated back to the 19th century and coincided with maximum Pb smelting at Freiberg and Pribram. In contrast, numerous previously studied sites showed no Pb accumulation maximum in the 19th century, but increasing pollution until the 1980s. It remains unclear why Ocean did not record the regional peak in Pb emissions caused by high coal and gasoline burning around 1980, while an array of nearby bogs studied previously did record the 1980 coal/gasoline peak, but no 1880 smelting peak. Mean 206Pb/ 207Pb ratios of potential pollution sources were 1.07 and 1.11 for gasoline, 1.17 and 1.17 for local ores, and 1.18 and 1.19 for coal in the U.K. and the Czech Republic, respectively. The calculated percentages of gasoline-derived Pb in peat (≤55% for the British Isles and ≤63% for the Czech Republic

Respiration and nitrogen assimilation: targeting mitochondria-associated metabolism as a means to enhance nitrogen use efficiency.

Science.gov (United States)

Foyer, Christine H; Noctor, Graham; Hodges, Michael

2011-02-01

Considerable advances in our understanding of the control of mitochondrial metabolism and its interactions with nitrogen metabolism and associated carbon/nitrogen interactions have occurred in recent years, particularly highlighting important roles in cellular redox homeostasis. The tricarboxylic acid (TCA) cycle is a central metabolic hub for the interacting pathways of respiration, nitrogen assimilation, and photorespiration, with components that show considerable flexibility in relation to adaptations to the different functions of mitochondria in photosynthetic and non-photosynthetic cells. By comparison, the operation of the oxidative pentose phosphate pathway appears to represent a significant limitation to nitrogen assimilation in non-photosynthetic tissues. Valuable new insights have been gained concerning the roles of the different enzymes involved in the production of 2-oxoglutarate (2-OG) for ammonia assimilation, yielding an improved understanding of the crucial role of cellular energy balance as a broker of co-ordinate regulation. Taken together with new information on the mechanisms that co-ordinate the expression of genes involved in organellar functions, including energy metabolism, and the potential for exploiting the existing flexibility for NAD(P)H utilization in the respiratory electron transport chain to drive nitrogen assimilation, the evidence that mitochondrial metabolism and machinery are potential novel targets for the enhancement of nitrogen use efficiency (NUE) is explored.

On nitrogen solubility in water

International Nuclear Information System (INIS)

Kalajda, Yu.A.; Katkov, Yu.D.; Kuznetsov, V.A.; Lastovtsev, A.Yu.; Lastochkin, A.P.; Susoev, V.S.

1980-01-01

Presented are the results of experimental investigations on nitrogen solubility in water under 0-15 MPa pressure, at the temperature of 100-340 deg C and nitrogen concentration of 0-5000 n.ml. N 2 /kg H 2 O. Empiric equations are derived and a diagram of nitrogen solubility in water is developed on the basis of the experimental data, as well as critically evaluated published data. The investigation results can be used in analyzing water-gas regime of a primary heat carrier in stream-generating plants with water-water reactors

The discharge characteristics in nitrogen helicon plasma

Science.gov (United States)

Zhao, Gao; Wang, Huihui; Si, Xinlu; Ouyang, Jiting; Chen, Qiang; Tan, Chang

2017-12-01

Discharge characteristics of helicon plasma in nitrogen and argon-nitrogen mixtures were investigated experimentally by using a Langmuir probe, a B-dot probe, and an optical emission spectrum. Helicon wave discharge is confirmed by the changes of electron density and electromagnetic signal amplitude with the increasing RF power, which shows three discharge stages in nitrogen, corresponding to E-mode, H-mode, and W-mode discharges in helicon plasma, respectively. Discharge images in the radial cross section at different discharge modes through an intensified charge coupled device (ICCD) show a rapid increase in luminous intensity along with the RF power. When the nitrogen discharge is in the W-mode, the images show that the strongest luminance locates near the plasma boundary and no blue core appears in the axial center of tube, which is always observed in argon W-mode discharge. The "big blue" or blue core is a special character in helicon plasma, but it has not been observed in nitrogen helicon plasma. In nitrogen-argon mixtures, a weak blue core is observed in ICCD images since the nitrogen content is increased. The electric field turns to the periphery in the distribution of the radial field and the electron temperature decreases with the increasing nitrogen content, especially when the blue core disappears. The different behaviors of the electron impact and the energy consumption in nitrogen helicon plasma are suggested to be responsible for the decrease in electron energy and the change in the electric field distribution.

Nitrogen evolution during rapid hydropyrolysis of coal

Energy Technology Data Exchange (ETDEWEB)

Xu, W.-C.; Kumagai, M. [Institute of Research and Innovation, Kashiwa (Japan)

2002-12-01

The behavior of nitrogen evolution during rapid hydropyrolysis of coal has been investigated at temperatures ranging from 923 to 1123 K and hydrogen pressure up to 5 MPa using a continuous free fall pyrolyzer. Three coals have been tested in this study. The dominant nitrogen gaseous species is ammonia, together with a little amount of HCN because most of HCN is converted to NH{sub 3} through secondary reactions. The results show that the evolution of nitrogen in coal is caused mainly by devolatilization at temperatures below 973 K, while the evolution of volatile nitrogen in char is accelerated with increasing temperature and hydrogen pressure. The mineral matter in coal act as catalysts to promote the evolution of volatile nitrogen in char to N{sub 2} apparently at high temperatures of 1123 K, as found during pyrolysis of coal by Ohtsuka et al. A pseudo-first-order kinetic model was applied to the evolution of nitrogen in coal during rapid hydropyrolysis. The model shows the activation energy for the nitrogen evolution from coal is 36.6 58.6 kJ/mol while the rate of the nitrogen evolution depends on hydrogen pressure in the order of 0.16 0.24. 41 refs., 11 figs., 3 tabs.

Physical-chemical processes of astrophysical interest: nitrogen chemistry

International Nuclear Information System (INIS)

Loison, Jean-Christophe; Hickson, Kevin; Hily-Blant, Pierre; Faure, Alexandre; Vuitton, Veronique; Bacmann, A.; Maret, Sebastien; Legal, Romane; Rist, Claire; Roncero, Octavio; Larregaray, Pascal; Hochlaf, Majdi; Senent, M. L.; Capron, Michael; Biennier, Ludovic; Carles, Sophie; Bourgalais, Jeremy; Le Picard, Sebastien; Cordier, Daniel; Guillemin, Jean-Claude; Trolez, Yann; Bertin, M.; Poderoso, H.A.M.; Michaut, X.; Jeseck, P.; Philippe, L.; Fillion, J.H.; Fayolle, E.C.; Linnartz, H.; Romanzin, C.; Oeberg, K.I.; Roueff, Evelyne; Pagani, Laurent; Padovani, Marco; Wakelam, Veronique; Honvault, Beatrice; Zvereva-Loete, Natalia; Ouk, Chanda-Malis; Scribano, Yohann; Hartmann, J.M.; Pineau des Forets, Guillaume; Hernandez, Mario; Lique, Francois; Kalugina, Yulia N.; Stoecklin, T.; Hochlaf, M.; Crespos, C.; Larregaray, P.; Martin-Gondre, L.; Petuya, R.; Quintas Sanchez, E.L.; Zanchet, Alexandre; Rodriguez-Lazcano, Yamilet; Mate, Belen

2013-06-01

This document contains the programme and abstracts of contributions to a workshop on nitrogen chemistry within an astrophysical perspective. These contributions have been presented in sessions: Introduction (opening lecture, experimental approaches to molecular astrophysics, theoretical approaches to astrophysics, observations in molecular astrophysics), Physical-chemical theory of the gas phase (time-dependent approach in elementary activity, statistic approach in elementary activity in the case of the N+H_2 reaction, potential energy surfaces for inelastic and reactive collisions, collision rate for N_2H"+, ortho/para selection rules in the chemistry of nitrogen hydrides, cyanides/iso-cyanides excitation in the ISM, CN excitation, radiative association with N_2H as new interstellar anion, ro-vibratory excitation of HCN) Laboratory astrophysics (measurement of reaction products in the CRESUSOL project, reactivity of the CN- anion, N_2 photo-desorption in ices, CRESU study of nitrogen chemistry, chemistry of nitrogen complex molecules), Observations and chemistry of astrophysical media (the problem of interstellar nitrogen fractioning, abundance of N_2 in proto-stellar cores, HNC in Titan atmosphere and nitrogen-related mechanisms in hot Jupiters, HCN and HNC in dark clouds or how theoretical modelling helps in interpreting observations, nitrogen chemistry in cold clouds, deuteration of nitrogen hydrides, nitrogen in interstellar ices, biochemical molecules on Titan, coupling between excitation and chemistry, radiative transfer of nitrogen hydrides, ortho/para chemistry of nitrogen hydrides), Physical-chemical theory of gas-grain interactions (nitrogen reactivity on surfaces, IR spectra of ices of NH_3 and NH_3/N_2 mixtures)

Nitrogen fate and Transport in Diverse Agricultural Watersheds

Science.gov (United States)

Essaid, H.; McCarthy, K. A.; Baker, N. T.

2010-12-01

Nitrogen mass budgets have been estimated for ten agricultural watersheds located in a range of hydrologic settings in order to understand the factors controlling the fate of nitrogen applied at the surface. The watersheds, study areas of the Agricultural Chemical Sources, Transport and Fate study of the U.S. Geological Survey National Water Quality Assessment Program, are located in Indiana (IN), Iowa (IA), Maryland (MD), Nebraska (NE), Mississippi (MS) and Washington (WA). They range in size from 7 to 1254 km2, with four of the watersheds nested within larger watersheds. Surface water outflow (normalized to watershed area) ranged from 4 to 83 cm/yr. Crops planted include corn, soybean, small grains, rice, cotton, orchards and vegetables. “Surplus nitrogen” was determined for each watershed by subtracting estimates of crop uptake and volatilization from estimates of nitrogen input from atmospheric deposition, plant fixation, and fertilizer and manure applications for the period from 1987 to 2004. This surplus nitrogen is transported though the watershed via surface and subsurface flow paths, while simultaneously undergoing transformations (such as denitrification and in-stream processing) that result in less export of nitrogen from the watershed. Surface-water discharge and concentration data were used to estimate the export of nitrogen from the watersheds (groundwater outflow from the watersheds was minimal). Subtracting nitrogen export from surplus nitrogen provides an estimate of the net amount of nitrogen removal occurring during internal watershed transport. Watershed average nitrogen surplus ranged from 6 to 49 kg-N/ha. The more permeable and/or greater water flux watersheds (MD, NE, and WA) tended to have larger surplus nitrogen, possibly due to less crop uptake caused by greater leaching and runoff of nitrogen. Almost all of the surplus nitrogen in the low permeability (MS) and tile drained watersheds (IA, IN) was exported from the watershed with

Nitrogen fixation in Red Sea seagrass meadows

KAUST Repository

Abdallah, Malak

2017-05-01

Seagrasses are key coastal ecosystems, providing many ecosystem services. Seagrasses increase biodiversity as they provide habitat for a large set of organisms. In addition, their structure provides hiding places to avoid predation. Seagrasses can grow in shallow marine coastal areas, but several factors regulate their growth and distribution. Seagrasses can uptake different kinds of organic and inorganic nutrients through their leaves and roots. Nitrogen and phosphorous are the most important nutrients for seagrass growth. Biological nitrogen fixation is the conversion of atmospheric nitrogen into ammonia by diazotrophic bacteria. This process provides a significant source of nitrogen for seagrass growth. The nitrogen fixation is controlled by the nif genes which are found in diazotrophs. The main goal of the project is to measure nitrogen fixation rates on seagrass sediments, in order to compare among various seagrass species from the Red Sea. Moreover, we will compare the fixing rates of the Vegetated areas with the bare sediments. This project will help to ascertain the role of nitrogen fixing bacteria in the development of seagrass meadows.

Apple wine processing with different nitrogen contents

Directory of Open Access Journals (Sweden)

Aline Alberti

2011-06-01

Full Text Available The aim of this work was to evaluate the nitrogen content in different varieties of apple musts and to study the effect of different nitrogen concentrations in apple wine fermentation. The average total nitrogen content in 51 different apples juices was 155.81 mg/L, with 86.28 % of the values above 100 mg/L. The apple must with 59.0, 122.0 and 163.0 mg/L of total nitrogen content showed the maximum population of 2.05x 10(7; 4.42 x 10(7 and 8.66 x 10(7 cell/mL, respectively. Therefore, the maximum fermentation rates were dependent on the initial nitrogen level, corresponding to 1.4, 5.1 and 9.2 g/L.day, respectively. The nitrogen content in the apple musts was an important factor of growth and fermentation velocity.

Enzymology and ecology of the nitrogen cycle.

Science.gov (United States)

Martínez-Espinosa, Rosa María; Cole, Jeffrey A; Richardson, David J; Watmough, Nicholas J

2011-01-01

The nitrogen cycle describes the processes through which nitrogen is converted between its various chemical forms. These transformations involve both biological and abiotic redox processes. The principal processes involved in the nitrogen cycle are nitrogen fixation, nitrification, nitrate assimilation, respiratory reduction of nitrate to ammonia, anaerobic ammonia oxidation (anammox) and denitrification. All of these are carried out by micro-organisms, including bacteria, archaea and some specialized fungi. In the present article, we provide a brief introduction to both the biochemical and ecological aspects of these processes and consider how human activity over the last 100 years has changed the historic balance of the global nitrogen cycle.

Understanding Nitrogen Fixation

Energy Technology Data Exchange (ETDEWEB)

Paul J. Chirik

2012-05-25

The purpose of our program is to explore fundamental chemistry relevant to the discovery of energy efficient methods for the conversion of atmospheric nitrogen (N{sub 2}) into more value-added nitrogen-containing organic molecules. Such transformations are key for domestic energy security and the reduction of fossil fuel dependencies. With DOE support, we have synthesized families of zirconium and hafnium dinitrogen complexes with elongated and activated N-N bonds that exhibit rich N{sub 2} functionalization chemistry. Having elucidated new methods for N-H bond formation from dihydrogen, C-H bonds and Broensted acids, we have since turned our attention to N-C bond construction. These reactions are particularly important for the synthesis of amines, heterocycles and hydrazines with a range of applications in the fine and commodity chemicals industries and as fuels. One recent highlight was the discovery of a new N{sub 2} cleavage reaction upon addition of carbon monoxide which resulted in the synthesis of an important fertilizer, oxamide, from the diatomics with the two strongest bonds in chemistry. Nitrogen-carbon bonds form the backbone of many important organic molecules, especially those used in the fertilizer and pharamaceutical industries. During the past year, we have continued our work in the synthesis of hydrazines of various substitution patterns, many of which are important precursors for heterocycles. In most instances, the direct functionalization of N{sub 2} offers a more efficient synthetic route than traditional organic methods. In addition, we have also discovered a unique CO-induced N{sub 2} bond cleavage reaction that simultaneously cleaves the N-N bond of the metal dinitrogen compound and assembles new C-C bond and two new N-C bonds. Treatment of the CO-functionalized core with weak Broensted acids liberated oxamide, H{sub 2}NC(O)C(O)NH{sub 2}, an important slow release fertilizer that is of interest to replace urea in many applications. The

Nitrogen on Mars: Insights from Curiosity

Science.gov (United States)

Stern, J. C.; Sutter, B.; Jackson, W. A.; Navarro-Gonzalez, Rafael; McKay, Chrisopher P.; Ming, W.; Archer, P. Douglas; Glavin, D. P.; Fairen, A. G.; Mahaffy, Paul R.

2017-01-01

Recent detection of nitrate on Mars indicates that nitrogen fixation processes occurred in early martian history. Data collected by the Sample Analysis at Mars (SAM) instrument on the Curiosity Rover can be integrated with Mars analog work in order to better understand the fixation and mobility of nitrogen on Mars, and thus its availability to putative biology. In particular, the relationship between nitrate and other soluble salts may help reveal the timing of nitrogen fixation and post-depositional behavior of nitrate on Mars. In addition, in situ measurements of nitrogen abundance and isotopic composition may be used to model atmospheric conditions on early Mars.

Diskurzivní analýza Národních listů: národ vs. islám a Laclauův populistický matrix

Directory of Open Access Journals (Sweden)

Ondřej Stulík

2016-08-01

Full Text Available This article deals with the phenomenon of populism and the form it takes in the context of the Úsvit – národní koalice party and the Blok proti islámu coalition. The methodology of the analysis is based on Laclau’s account of populism and includes a discursive analysis of the populist mentality as a tool to form a vague argument against “bad” Islam culture. These assumptions are tested by a summative content analysis and are contextualized by a metaphor analysis. The results confirm all assumptions: Úsvit and Blok create a specific populist mentality based on a negative perception of Islam, a positive (but empty national identity, and a simplified critique of the current establishment framed as tool for spreading bad culture which is based on the ideology of Muslims and Islam.

Influence of the form and rate of 15N-labelled nitrogen fertilizers on nitrogen uptake by maize grown on two different soils

International Nuclear Information System (INIS)

Balabanova-Georgieva, R.; Ikonomova, E.

1996-01-01

The influence of 15 N-labelled urea and ammonium sulfate on the yield and uptake of fertilizer nitrogen and soil nitrogen by maize was studied under the conditions of pot experiments on calcareous black earth and leached black earth. The nitrogen fertilizers were applied in rates: N 1 =250 mg, N 2 =500 mg, N 3 =750 mg and N 4 =1000 mg/1 kg of soil, on phosphorus(P)-potassium(K) background (P=200 and K=600 mg/kg soil). When treating with N 3 and N 4 , the application of the whole nitrogen rate was compared with its split application. It was found that the form of the nitrogen fertilizer played no important role for the formation of the yield of biomass and the uptake of nitrogen with the yield when it is applied in low nitrogen rates and maize was grown on calcareous black earth. The yield of biomass and the uptake of nitrogen with the yield of maize reach their maximum under the conditions of calcareous black earth and high nitrogen rates applied as urea depressed the plants which proves the statement that in case of calcareous black earth application of ammonium sulfate should be preferred rather that urea, fertilization with which should be avoided. No depression of plants was observed under the conditions of leached black earth and application of high urea rates. The amount of nitrogen taken up is growing with the increasing of the nitrogen rate (excluding the N-treatment). The split application of high nitrogen rates increased notably the yield of maize-vegetation mass which proved the great ability of this crop for effective utilization of the nitrogen fertilizers when applied in portions and at suitable phases of plant vegetation. The role of the fertilizer nitrogen on the formation of the plant mass yield is much greater compared to that of the soil nitrogen; in the split application of urea the soil nitrogen plays a much bigger role than in its single application. The additional mobilization of the soil nitrogen under the influence of the applied nitrogen

Engineering Pseudomonas protegens Pf-5 for Nitrogen Fixation and its Application to Improve Plant Growth under Nitrogen-Deficient Conditions

Science.gov (United States)

Setten, Lorena; Soto, Gabriela; Mozzicafreddo, Matteo; Fox, Ana Romina; Lisi, Christian; Cuccioloni, Massimiliano; Angeletti, Mauro; Pagano, Elba; Díaz-Paleo, Antonio; Ayub, Nicolás Daniel

2013-01-01

Nitrogen is the second most critical factor for crop production after water. In this study, the beneficial rhizobacterium Pseudomonas protegens Pf-5 was genetically modified to fix nitrogen using the genes encoding the nitrogenase of Pseudomonas stutzeri A1501 via the X940 cosmid. Pf-5 X940 was able to grow in L medium without nitrogen, displayed high nitrogenase activity and released significant quantities of ammonium to the medium. Pf-5 X940 also showed constitutive expression and enzymatic activity of nitrogenase in ammonium medium or in nitrogen-free medium, suggesting a constitutive nitrogen fixation. Similar to Pseudomonas protegens Pf-5, Pseudomonas putida, Pseudomonas veronii and Pseudomonas taetrolens but not Pseudomonas balearica and Pseudomonas stutzeri transformed with cosmid X940 showed constitutive nitrogenase activity and high ammonium production, suggesting that this phenotype depends on the genome context and that this technology to obtain nitrogen-fixing bacteria is not restricted to Pf-5. Interestingly, inoculation of Arabidopsis, alfalfa, tall fescue and maize with Pf-5 X940 increased the ammonium concentration in soil and plant productivity under nitrogen-deficient conditions. In conclusion, these results open the way to the production of effective recombinant inoculants for nitrogen fixation on a wide range of crops. PMID:23675499

Nitrogen narcosis induced by repetitive hyperbaric nitrogen oxygen mixture exposure impairs long-term cognitive function in newborn mice.

Directory of Open Access Journals (Sweden)

Bin Peng

Full Text Available Human beings are exposed to compressed air or a nitrogen-oxygen mixture, they will produce signs and symptoms of nitrogen narcosis such as amnesia or even loss of memory, which may be disappeared once back to the normobaric environment. This study was designed to investigate the effect of nitrogen narcosis induced by repetitive hyperbaric nitrogen-oxygen mixture exposure on long-term cognitive function in newborn mice and the underlying mechanisms. The electroencephalogram frequency was decreased while the amplitude was increased in a pressure-dependent manner during 0.6, 1.2, 1.8 MPa (million pascal nitrogen-oxygen mixture exposures in adult mice. Nitrogen narcosis in postnatal days 7-9 mice but not in adult mice induced by repetitive hyperbaric exposure prolonged the latency to find the platform and decreased the number of platform-site crossovers during Morris water maze tests, and reduced the time in the center during the open field tests. An increase in the expression of cleaved caspase-3 in the hippocampus and cortex were observed immediately on the first day after hyperbaric exposure, and this lasted for seven days. Additionally, nitrogen narcosis induced loss of the dendritic spines but not of the neurons, which may mainly account for the cognitive dysfunction. Nitrogen narcosis induced long-term cognitive and emotional dysfunction in the postnatal mice but not in the adult mice, which may result from neuronal apoptosis and especially reduction of dendritic spines of neurons.

Cosmological evolution of the nitrogen abundance

Science.gov (United States)

Vangioni, Elisabeth; Dvorkin, Irina; Olive, Keith A.; Dubois, Yohan; Molaro, Paolo; Petitjean, Patrick; Silk, Joe; Kimm, Taysun

2018-06-01

The abundance of nitrogen in the interstellar medium is a powerful probe of star formation processes over cosmological time-scales. Since nitrogen can be produced both in massive and intermediate-mass stars with metallicity-dependent yields, its evolution is challenging to model, as evidenced by the differences between theoretical predictions and observations. In this work, we attempt to identify the sources of these discrepancies using a cosmic evolution model. To further complicate matters, there is considerable dispersion in the abundances from observations of damped Lyα absorbers (DLAs) at z ˜ 2-3. We study the evolution of nitrogen with a detailed cosmic chemical evolution model and find good agreement with these observations, including the relative abundances of (N/O) and (N/Si). We find that the principal contribution of nitrogen comes from intermediate-mass stars, with the exception of systems with the lowest N/H, where nitrogen production might possibly be dominated by massive stars. This last result could be strengthened if stellar rotation which is important at low metallicity can produce significant amounts of nitrogen. Moreover, these systems likely reside in host galaxies with stellar masses below 108.5 M⊙. We also study the origin of the observed dispersion in nitrogen abundances using the cosmological hydrodynamical simulations Horizon-AGN. We conclude that this dispersion can originate from two effects: difference in the masses of the DLA host galaxies, and difference in their position inside the galaxy.

Mineralization of nitrogen by protozoan activity in soil

NARCIS (Netherlands)

Kuikman, P.

1990-01-01

In general, more than 95% of the nitrogen in soils is present in organic forms. This nitrogen is not directly available to plants unless microbial decomposition takes place with the release of mineral nitrogen. In modern agriculture, nitrogen is often applied to arable soils as a fertilizer

Nitrogen Soil Testing for Corn in Virginia

OpenAIRE

Evanylo, Gregory K.; Alley, Marcus M., 1947-

2009-01-01

An adequate supply of plant-available nitrogen (N) is crucial for efficient corn production, and corn N requirements are greater than any other nutrient. This publication reviews the link between nitrogen and corn production, nitrogen behavior, soil testing, test procedures and recommendations.

Utilization of urea-nitrogen-15 in ruminants

International Nuclear Information System (INIS)

Boda, K.; Varady, J.; Havassy, I.

1976-01-01

In Merino sheep a series of experiments were carried out investigating exogenous and endogenous urea utilization. On the experimental sheep with isolated jejunum, rumen and intestine fistula, re-entral intestine cannulae, and after intra-ruminal or intra-intestinal 15 N-urea administration it was found that urea- 15 N takes part in the nitrogen recycling, and is utilized in the nitrogen pool. In experiments with synthetic protein-free diet, low protein diet and high nitrogen diet, after the intravenous administration of 15 N-urea the following findings were made: The results of experiments with synthetic diet, where the only nitrogen source was perorally (for 3-6 months) and then intravenously (for 3 months) administered urea, indicated the ability of ruminants to replace fully the nitrogen in the feed under certain conditions by increased endogenous urea recirculation. The results of the experiments with various nitrogen intakes showed that considerable amounts of urea- 15 N (44-96% from the given dose) were retained. Nitrogen compounds synthetized from blood urea- 15 N were recycled through the alimentary tract. Its secretion predominated in the forestomachs, abomasum and duodenum, and its reabsorption took place in the intestinal tract. From the 15 N incorporated into the nitrogenous substances which passed through the duodenum, 73-84% was reabsorbed. The retained 15 N was incorporated into the microbial and plasma proteins and its amide-N. On the basis of these results it is concluded that in addition to the rumeno-hepatal circulation, the entero-hepatal circulation of nitrogenous substances, including endogenous nitrogen, also plays an important role quantitatively and perhaps qualitatively in the process of re-utilizing the blood urea N for proteosynthesis and synthesis of other N-metabolites in ruminants. The hydrolysis of endogenous urea in the gastro-intestinal tract of ruminants and its utilization is a natural process indispensable for the maintenance of

Toward a nitrogen footprint calculator for Tanzania

Science.gov (United States)

Hutton, Mary Olivia; Leach, Allison M.; Leip, Adrian; Galloway, James N.; Bekunda, Mateete; Sullivan, Clare; Lesschen, Jan Peter

2017-03-01

We present the first nitrogen footprint model for a developing country: Tanzania. Nitrogen (N) is a crucial element for agriculture and human nutrition, but in excess it can cause serious environmental damage. The Sub-Saharan African nation of Tanzania faces a two-sided nitrogen problem: while there is not enough soil nitrogen to produce adequate food, excess nitrogen that escapes into the environment causes a cascade of ecological and human health problems. To identify, quantify, and contribute to solving these problems, this paper presents a nitrogen footprint tool for Tanzania. This nitrogen footprint tool is a concept originally designed for the United States of America (USA) and other developed countries. It uses personal resource consumption data to calculate a per-capita nitrogen footprint. The Tanzania N footprint tool is a version adapted to reflect the low-input, integrated agricultural system of Tanzania. This is reflected by calculating two sets of virtual N factors to describe N losses during food production: one for fertilized farms and one for unfertilized farms. Soil mining factors are also calculated for the first time to address the amount of N removed from the soil to produce food. The average per-capita nitrogen footprint of Tanzania is 10 kg N yr-1. 88% of this footprint is due to food consumption and production, while only 12% of the footprint is due to energy use. Although 91% of farms in Tanzania are unfertilized, the large contribution of fertilized farms to N losses causes unfertilized farms to make up just 83% of the food production N footprint. In a developing country like Tanzania, the main audiences for the N footprint tool are community leaders, planners, and developers who can impact decision-making and use the calculator to plan positive changes for nitrogen sustainability in the developing world.

Nitrogen in Agricultural Systems: Implications for Conservation Policy

OpenAIRE

Ribaudo, Marc; Delgado, Jorge; Hansen, LeRoy T.; Livingston, Michael J.; Mosheim, Roberto; Williamson, James M.

2011-01-01

Nitrogen is an important agricultural input that is critical for crop production. However, the introduction of large amounts of nitrogen into the environment has a number of undesirable impacts on water, terrestrial, and atmospheric resources. This report explores the use of nitrogen in U.S. agriculture and assesses changes in nutrient management by farmers that may improve nitrogen use effi ciency. It also reviews a number of policy approaches for improving nitrogen management and identifi e...

Efficient assimilation of cyanobacterial nitrogen by water hyacinth.

Science.gov (United States)

Qin, Hongjie; Zhang, Zhiyong; Liu, Minhui; Wang, Yan; Wen, Xuezheng; Yan, Shaohua; Zhang, Yingying; Liu, Haiqin

2017-10-01

A 15 N labeling technique was used to study nitrogen transfer from cyanobacterium Microcystis aeruginosa to water hyacinth. 15 N atom abundance in M. aeruginosa peaked (15.52%) after cultivation in 15 N-labeled medium for 3weeks. Over 87% of algal nitrogen was transferred into water hyacinth after the 4-week co-cultivation period. The nitrogen quickly super-accumulated in the water hyacinth roots, and the labeled nitrogen was re-distributed to different organs (i.e., roots, stalks, and leaves). This study provides a new strategy for further research on cyanobacterial bloom control, nitrogen migration, and nitrogen cycle in eutrophic waters. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nitrogenous air pollutants: Chemical and biological implications

International Nuclear Information System (INIS)

Grosjean, D.

1979-01-01

Theoretical and experimental studies on the health effects and chemistry of gaseous and particulate nitrogenous air pollutants are presented. Specific topics include Fourier transform infrared studies of nitrogenous compounds, the mechanism of peroxynitric acid formation, N-nitroso compounds in the air, the chemical transformations of nitrogen oxides during the sampling of combustion products, the atmospheric chemistry of peroxy nitrates, and the effects of nitrogen dioxide on lung metabolism. Attention is also given to the interaction of nitrogen oxides and aromatic hydrocarbons under simulated atmospheric conditions, the characterization of particulate amines, the role of ammonia in atmospheric aerosol chemistry, the relationship between sulfates and nitrates and tropospheric measurements of nitric acid vapor and particulate nitrates

Deposition of nitrogen into the North Sea

DEFF Research Database (Denmark)

Leeuw, G. de; Skjøth, C.A.; Hertel, O.

2003-01-01

The flux of nitrogen species from the atmosphere into the ocean, with emphasis on coastal waters, was addressed during the ANICE project (Atmospheric Nitrogen Inputs into the Coastal Ecosystem). ANICE focused on quantifying the deposition of atmospheric inputs of inorganic nitrogen compounds (HNO3...... and Harwich/Newcastle. These measurements provided data for sensitivity studies of a variety of problems associated with the coastal region that are not easily evaluated with larger scale models, to constrain models and to test model results. Concentrations of nitrogen compounds over the North Sea...... on experimental results and small-scale model studies. In particular, effects of the aerosol size distribution on the nitrogen deposition are discussed. (C) 2003 Elsevier Ltd. All rights reserved....

Leaf nitrogen assimilation and partitioning differ among subtropical forest plants in response to canopy addition of nitrogen treatments

Science.gov (United States)

Nan Liu; Shuhua Wu; Qinfeng Guo; Jiaxin Wang; Ce Cao; Jun Wang

2018-01-01

Global increases in nitrogen deposition may alter forest structure and function by interferingwith plant nitrogen metabolism (e.g., assimilation and partitioning) and subsequent carbon assimilation, but it is unclear how these responses to nitrogen deposition differ among species. In this study, we conducted a 2-year experiment to investigate the effects of canopy...

Nitrogen concentration estimation with hyperspectral LiDAR

Directory of Open Access Journals (Sweden)

O. Nevalainen

2013-10-01

Full Text Available Agricultural lands have strong impact on global carbon dynamics and nitrogen availability. Monitoring changes in agricultural lands require more efficient and accurate methods. The first prototype of a full waveform hyperspectral Light Detection and Ranging (LiDAR instrument has been developed at the Finnish Geodetic Institute (FGI. The instrument efficiently combines the benefits of passive and active remote sensing sensors. It is able to produce 3D point clouds with spectral information included for every point which offers great potential in the field of remote sensing of environment. This study investigates the performance of the hyperspectral LiDAR instrument in nitrogen estimation. The investigation was conducted by finding vegetation indices sensitive to nitrogen concentration using hyperspectral LiDAR data and validating their performance in nitrogen estimation. The nitrogen estimation was performed by calculating 28 published vegetation indices to ten oat samples grown in different fertilization conditions. Reference data was acquired by laboratory nitrogen concentration analysis. The performance of the indices in nitrogen estimation was determined by linear regression and leave-one-out cross-validation. The results indicate that the hyperspectral LiDAR instrument holds a good capability to estimate plant biochemical parameters such as nitrogen concentration. The instrument holds much potential in various environmental applications and provides a significant improvement to the remote sensing of environment.

Nitrogen compounds behavior under irradiation environment

International Nuclear Information System (INIS)

Ichikawa, Nagayoshi; Takagi, Junichi; Yotsuyanagi, Tadasu

1991-01-01

Laboratory experiments were performed to evaluate nitrogen compounds behavior in liquid phase under irradiation environments. Nitrogen compounds take a chemical form of ammonium ion under reducing condition by gamma irradiation, whereas ammonium ions are rather stable even under oxidizing conditions. Key reactions were pointed out and their reaction rate constants and activation energies were estimated through computer code simulation. A reaction scheme for nitrogen compounds including protonate reaction was proposed. (author)

Food, Feed and Fuel: a Story About Nitrogen

Science.gov (United States)

Galloway, J. N.; Burke, M. B.; Mooney, H. A.; Steinfeld, H.

2008-12-01

Humans obtain metabolic energy by eating food. Nitrogen is required to grow food, but natural supplies of N for human purposes have been inadequate since the beginning of the twentieth century. The Haber-Bosch process now provides a virtually inexhaustible supply of nitrogen, limited primarily by the cost of energy. However, most nitrogen used in food production is lost to the environment, where it cascades through environmental reservoirs contributing to many of the major environmental issues of the day. Furthermore, growing international trade in nitrogen-containing commodities is increasingly replacing wind and water as an important international transporter of nitrogen around the globe. Finally, the rapid growth in crop-based biofuels, and its attendant effects on the global production and trade of all agricultural commodities, could greatly affect global patterns of N use and loss. In the light of the findings above, this paper examines the role of nitrogen in food, feed and fuel production. It describes the beneficial consequences for food production and the negative consequences associated with the commodity nitrogen cascade and the environmental nitrogen cascade. The paper reviews estimates of future projections of nitrogen demands for food and fuel, including the impact of changing diets in the developing world. The paper concludes by presenting the potential interactions among global change, agricultural production and the nitrogen and carbon cycles.

Automatic liquid nitrogen feeding device

International Nuclear Information System (INIS)

Gillardeau, J.; Bona, F.; Dejachy, G.

1963-01-01

An automatic liquid nitrogen feeding device has been developed (and used) in the framework of corrosion tests realized with constantly renewed uranium hexafluoride. The issue was to feed liquid nitrogen to a large capacity metallic trap in order to condensate uranium hexafluoride at the exit of the corrosion chambers. After having studied various available devices, a feeding device has been specifically designed to be robust, secure and autonomous, as well as ensuring a high liquid nitrogen flowrate and a highly elevated feeding frequency. The device, made of standard material, has been used during 4000 hours without any problem [fr

Spatial pattern of nitrogen deposition flux over Czech forests: a novel approach accounting for unmeasured nitrogen species

Science.gov (United States)

Hůnová, Iva; Stoklasová, Petra; Kurfürst, Pavel; Vlček, Ondřej; Schovánková, Jana; Stráník, Vojtěch

2015-04-01

Nitrogen plays an important role in the biogeochemistry of forests as an essential plant nutrient and indispensable substance for many reactions in living cell. Most temperate forests are N-limited (Townsend, 1999), and increased nitrogen deposition results in many negative environmental effects, such as eutrofication, acidification, and loss of biodiversity (Bobbink et al., 2010). The nitrogen biogeochemical cycle is still poorly understood (Fowler et al., 2014). In studies addressing the association between atmospheric deposition and its impacts on ecosystems, a reliable estimation of N deposition is a key factor of successful approach of this issue. The quantification of real deposition of nitrogen is a complicated task, however, due to several reasons: only some constituents are regularly measured, and throughfall is not a relevant proxy for estimation of the total deposition due to complicated interchange of nitrogen between forest canopy, understory, and atmosphere. There are studies estimating the total nitrogen deposition at one particular site, on the other hand, there are studies estimating the total nitrogen deposition over a larger domain, such as e.g. Europe. The studies for a middle scale, like one country, are practically lacking with few exceptions (Fowler et al., 2005). The advantage of such a country-scale approach is that measured constituents might be mapped in detail, which enhances also spatial accuracy and reliability. The ambient air quality monitoring in the Czech Republic is paid an appreciable attention (Hůnová, 2001) due to the fact, that in the recent past its territory belonged to the most polluted parts of Europe. The time trends and spatial patterns of atmospheric deposition were published (Hůnová et al. 2014). It is obvious, however, that nitrogen deposition is substantially underestimated, particularly due not fully accounted for dry and occult deposition. We present an advanced approach for estimation of spatial pattern of

Voluntary intake, nitrogen metabolism and rumen fermentation ...

African Journals Online (AJOL)

Voluntary intake, nitrogen metabolism and rumen fermentation patterns in sheep given cowpea, silverleaf desmodium and fine-stem stylo legume hays as ... utilisation, the negative nitrogen retentions might indicate the inadequacy of the specific legume hays used as nitrogen supplementary feeds to sheep fed a basal diet

84 K nitrogen system for the SSC

International Nuclear Information System (INIS)

McAshan, M.; Thirumaleshwar, M.; Abramovich, S.; Ganni, V.; Scheidemantle, A.

1992-01-01

The nitrogen system for the Superconducting Super Collider (SSC) is designed to provide the 84 K (nominal) shield refrigeration for the collider rings. Liquid nitrogen is supplied to the collider tunnel from one, two, or more locations on the surface through the service shafts and is distributed along, the 87 km of both rings by the 84 K shield lines. Additional design requirements for the nitrogen distribution system include precooling, fluid supply to the helium plants, supplying makeup liquid nitrogen to the reservoirs located at the entrance of the main shafts, and providing an efficient cooldown means for the cold mass from 300 K to 90 K. The operational modes and possible emergency and maintenance conditions of the collider are taken into account for the nitrogen system design. The status of our work, including design considerations that address thermal aspects (heat load, recooling scheme, etc.) and hydraulic aspects (pressures, elevations, distances, etc.) of the nitrogen system will be discussed

Isotope studies on the comparative efficiency of nitrogenous sources

Energy Technology Data Exchange (ETDEWEB)

Dev, G; Rennie, D A [Saskatchewan Univ., Saskatoon (Canada). Dept. of Soil Science

1979-03-01

In a growth chamber experiment with /sup 15/N-labelled potassium nitrate, ammonium sulphate and urea at 75 and 150kg nitrogen/ha and ammonium nitrate at 150kg nitrogen/ha, nitrogen application produced significant responses of dry matter yield and total nitrogen uptake by shoot and root of barley in chernozemic dark brown Elstow silt loam and deep black Hoey clay soil. Total nitrogen removal per pot and isotope-derived criteria, viz. percentage nitrogen derived from fertilizer, 'A' value and percentage fertilizer nitrogen utilization, indicated that potassium nitrate was the most efficient and urea the least.

Export of nitrogen from catchments: A worldwide analysis

International Nuclear Information System (INIS)

Alvarez-Cobelas, M.; Angeler, D.G.; Sanchez-Carrillo, S.

2008-01-01

This study reviews nitrogen export rates from 946 rivers of the world to determine the influence of quantitative (runoff, rainfall, inhabitant density, catchment area, percentage of land use cover, airborne deposition, fertilizer input) and qualitative (dominant type of forest, occurrence of stagnant waterbodies, dominant land use, occurrence of point sources, runoff type) environmental factors on nitrogen fluxes. All fractions (total, nitrate, ammonia, dissolved organic and particulate organic) of nitrogen export showed a left-skewed distribution, which suggests a relatively pristine condition for most systems. Total nitrogen export showed the highest variability whereas total organic nitrogen export comprised the dominant fraction of export. Nitrogen export rates were only weakly explained by our qualitative and quantitative environmental variables. Our study suggests that the consideration of spatial and temporal scales is important for predicting nitrogen export rates using simple and easy-to-get environmental variables. Regionally based modelling approaches prove more useful than global-scale analyses. - Spatial and temporal scales are important determinants for nitrogen export from catchments and emphasis should be put on regional approaches

Change in gene abundance in the nitrogen biogeochemical cycle with temperature and nitrogen addition in Antarctic soils.

Science.gov (United States)

Jung, Jaejoon; Yeom, Jinki; Kim, Jisun; Han, Jiwon; Lim, Hyoun Soo; Park, Hyun; Hyun, Seunghun; Park, Woojun

2011-12-01

The microbial community (bacterial, archaeal, and fungi) and eight genes involved in the nitrogen biogeochemical cycle (nifH, nitrogen fixation; bacterial and archaeal amoA, ammonia oxidation; narG, nitrate reduction; nirS, nirK, nitrite reduction; norB, nitric oxide reduction; and nosZ, nitrous oxide reduction) were quantitatively assessed in this study, via real-time PCR with DNA extracted from three Antarctic soils. Interestingly, AOB amoA was found to be more abundant than AOA amoA in Antarctic soils. The results of microcosm studies revealed that the fungal and archaeal communities were diminished in response to warming temperatures (10 °C) and that the archaeal community was less sensitive to nitrogen addition, which suggests that those two communities are well-adapted to colder temperatures. AOA amoA and norB genes were reduced with warming temperatures. The abundance of only the nifH and nirK genes increased with both warming and the addition of nitrogen. NirS-type denitrifying bacteria outnumbered NirK-type denitrifiers regardless of the treatment used. Interestingly, dramatic increases in both NirS and NirK-types denitrifiers were observed with nitrogen addition. NirK types increase with warming, but NirS-type denitrifiers tend to be less sensitive to warming. Our findings indicated that the Antarctic microbial nitrogen cycle could be dramatically altered by temperature and nitrogen, and that warming may be detrimental to the ammonia-oxidizing archaeal community. To the best of our knowledge, this is the first report to investigate genes associated with each process of the nitrogen biogeochemical cycle in an Antarctic terrestrial soil environment. Copyright © 2011 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Nitrogen-fixing bacteria in Mediterranean seagrass (Posidonia oceanica) roots

KAUST Repository

Garcias Bonet, Neus

2016-03-09

Biological nitrogen fixation by diazotrophic bacteria in seagrass rhizosphere and leaf epiphytic community is an important source of nitrogen required for plant growth. However, the presence of endophytic diazotrophs remains unclear in seagrass tissues. Here, we assess the presence, diversity and taxonomy of nitrogen-fixing bacteria within surface-sterilized roots of Posidonia oceanica. Moreover, we analyze the nitrogen isotopic signature of seagrass tissues in order to notice atmospheric nitrogen fixation. We detected nitrogen-fixing bacteria by nifH gene amplification in 13 out of the 78 roots sampled, corresponding to 9 locations out of 26 meadows. We detected two different types of bacterial nifH sequences associated with P. oceanica roots, which were closely related to sequences previously isolated from the rhizosphere of a salt marsh cord grass and a putative anaerobe. Nitrogen content of seagrass tissues showed low isotopic signatures in all the sampled meadows, pointing out the atmospheric origin of the assimilated nitrogen by seagrasses. However, this was not related with the presence of endophytic nitrogen fixers, suggesting the nitrogen fixation occurring in rhizosphere and in the epiphytic community could be an important source of nitrogen for P. oceanica. The low diversity of nitrogen-fixing bacteria reported here suggests species-specific relationships between diazotrophs and P. oceanica, revealing possible symbiotic interactions that could play a major role in nitrogen acquisition by seagrasses in oligotrophic environments where they form lush meadows.

The Crownpoint and Churchrock uranium deposits, San Juan Basin, New Mexico: An ISL mining perspective

International Nuclear Information System (INIS)

McCarn, D.W.

2001-01-01

The Crownpoint and Churchrock uranium deposits, San Juan Basin, New Mexico are currently being developed by Uranium Resources, Inc. (URI) and its subsidiary Hydro Resources, Inc. (HRI) with an anticipated start-up in 1998. Both deposits will be developed using advanced in situ leach (ISL) mining techniques. URI/HRI currently has about 14,583 t U (37.834 million pounds U 3 O 8 ) of estimated recoverable reserves at Crownpoint and Churchrock. at a cost less than $39/kg U ($15/lb U 3 O 8 ). The uranium endowment of the San Juan Basin is the largest of any province in the USA. In March, 1997, a Final Environmental Impact Statement (FEIS) for the Crownpoint and Churchrock sites was completed by the Nuclear Regulatory Commission which recommends the issuance of an operating license. The FEIS is the culmination of a 9 year effort to license and develop the deposits. The Westwater Canyon Member of the Jurassic Morrison Formation is an arkosic, fine to coarse grained sandstone bounded by near basinwide confining clays deposited in a wet alluvial fan environment within the San Juan Basin. The primary, trend-ore deposits are hosted by the Westwater Canyon Member as humate-rich, syngenetic tabular deposits which were subsequently remobilized into roll fronts. Since deposition in the Jurassic, two phases of remobilization have occurred in the basin causing the formation of in situ leach amenable monometallic uranium rolls free of organic debris. Following in situ mining, ground water restoration of the Crownpoint and Churchrock mines is required to provide a water quality consistent with pre-mining baseline conditions. The development of in situ mining offers an environmentally sound and cost-effective method for uranium extraction. URI/HRI anticipates a production of 385-1,156 Tonnes U/year (1-3 million pounds U 3 O 8 ) from the New Mexico properties. (author)

Isotope investigation of nitrogen in the hydrosphere

International Nuclear Information System (INIS)

Heaton, T.H.E.

1985-01-01

Compounds of nitrogen are essential, often limiting nutrients, and the nitrogen cycle is therefore one of the most important of the earth's major elements cycles. Of all the cycles, however, the nitrogen cycle is also probably the one most influenced by human activity. This activity has resulted in the increase in reactive nitrogen compounds to such an extent that they now present major forms of pollution. Any strategies aimed at counteracting these disturbances require a better understanding of the sources and reaction processes for nitrogen compounds, and studies of natural variations in 15 N/ 14 N ratio are now being used for this purpose in all parts of the hydrosphere. This paper reviews the isotopic method for tracing sources of nitrate in ground and surface waters

Acidification and Nitrogen Eutrophication of Austrian Forest Soils

Directory of Open Access Journals (Sweden)

Robert Jandl

2012-01-01

Full Text Available We evaluated the effect of acidic deposition and nitrogen on Austrian forests soils. Until thirty years ago air pollution had led to soil acidification, and concerns on the future productivity of forests were raised. Elevated rates of nitrogen deposition were believed to cause nitrate leaching and imbalanced forest nutrition. We used data from a soil monitoring network to evaluate the trends and current status of the pH and the C : N ratio of Austrian forest soils. Deposition measurements and nitrogen contents of Norway spruce needles and mosses were used to assess the nitrogen supply. The pH values of soils have increased because of decreasing proton depositions caused by reduction of emissions. The C : N ratio of Austrian forest soils is widening. Despite high nitrogen deposition rates the increase in forest stand density and productivity has increased the nitrogen demand. The Austrian Bioindicator Grid shows that forest ecosystems are still deficient in nitrogen. Soils retain nitrogen efficiently, and nitrate leaching into the groundwater is presently not a large-scale problem. The decline of soil acidity and the deposition of nitrogen together with climate change effects will further increase the productivity of the forests until a limiting factor such as water scarcity becomes effective.

Replaceable liquid nitrogen piping

International Nuclear Information System (INIS)

Yasujima, Yasuo; Sato, Kiyoshi; Sato, Masataka; Hongo, Toshio

1982-01-01

This liquid nitrogen piping with total length of about 50 m was made and installed to supply the liquid nitrogen for heat insulating shield to three superconducting magnets for deflection and large super-conducting magnet for detection in the π-meson beam line used for high energy physics experiment in the National Laboratory for High Energy Physics. The points considered in the design and manufacture stages are reported. In order to minimize the consumption of liquid nitrogen during transport, vacuum heat insulation method was adopted. The construction period and cost were reduced by the standardization of the components, the improvement of welding works and the elimination of ineffective works. For simplifying the maintenance, spare parts are always prepared. The construction and the procedure of assembling of the liquid nitrogen piping are described. The piping is of double-walled construction, and its low temperature part was made of SUS 316L. The super-insulation by aluminum vacuum evaporation and active carbon were attached on the external surface of the internal pipe. The final leak test and the heating degassing were performed. The tests on evacuation, transport capacity and heat entry are reported. By making the internal pipe into smaller size, the piping may be more efficient. (Kako, I.)

Effects of water and nitrogen availability on nitrogen contribution by the legume, Lupinus argenteus Pursh

Science.gov (United States)

Erin Goergen; Jeanne C. Chambers; Robert Blank

2009-01-01

Nitrogen-fixing species contribute to ecosystem nitrogen budgets, but background resource levels influence nodulation, fixation, and plant growth. We conducted a greenhouse experiment to examine the separate and interacting effects of water and N availability on biomass production, tissue N concentration, nodulation, nodule activity, and rhizodeposition of ...

Nitrogen-doped carbon aerogels for electrical energy storage

Science.gov (United States)

Campbell, Patrick; Montalvo, Elizabeth; Baumann, Theodore F.; Biener, Juergen; Merrill, Matthew; Reed, Eric W.; Worsley, Marcus A.

2017-10-03

Disclosed here is a method for making a nitrogen-doped carbon aerogel, comprising: preparing a reaction mixture comprising formaldehyde, at least one nitrogen-containing resorcinol analog, at least one catalyst, and at least one solvent; curing the reaction mixture to produce a wet gel; drying the wet gel to produce a dry gel; and thermally annealing the dry gel to produce the nitrogen-doped carbon aerogel. Also disclosed is a nitrogen-doped carbon aerogel obtained according to the method and a supercapacitor comprising the nitrogen-doped carbon aerogel.

Inorganic nitrogen in precipitation and atmospheric sediments

Energy Technology Data Exchange (ETDEWEB)

Matheson, D H

1951-01-01

In an investigation covering 18 months, daily determinations were made of the inorganic nitrogen contained in precipitation and atmospheric sediments collected at Hamilton, Ont. The nitrogen fall for the whole period averaged 5.8 lb. N per acre per year. Sixty-one per cent of the total nitrogen was collected on 25% of the days when precipitation occurred. The balance, occurring on days without precipitation, is attributable solely to the sedimentation of dust. Ammonia nitrogen averaged 56% of the total, but the proportion for individual days varied widely.

Estimating Nitrogen Load Resulting from Biofuel Mandates

Science.gov (United States)

Alshawaf, Mohammad; Douglas, Ellen; Ricciardi, Karen

2016-01-01

The Energy Policy Act of 2005 and the Energy Independence and Security Act (EISA) of 2007 were enacted to reduce the U.S. dependency on foreign oil by increasing the use of biofuels. The increased demand for biofuels from corn and soybeans could result in an increase of nitrogen flux if not managed properly. The objectives of this study are to estimate nitrogen flux from energy crop production and to identify the catchment areas with high nitrogen flux. The results show that biofuel production can result in an increase of nitrogen flux to the northern Gulf of Mexico from 270 to 1742 thousand metric tons. Using all cellulosic (hay) ethanol or biodiesel to meet the 2022 mandate is expected to reduce nitrogen flux; however, it requires approximately 25% more land when compared to other scenarios. Producing ethanol from switchgrass rather than hay results in three-times more nitrogen flux, but requires 43% less land. Using corn ethanol for 2022 mandates is expected to have double the nitrogen flux when compared to the EISA-specified 2022 scenario; however, it will require less land area. Shifting the U.S. energy supply from foreign oil to the Midwest cannot occur without economic and environmental impacts, which could potentially lead to more eutrophication and hypoxia. PMID:27171101

Nitrogen determination on tomato ( Lycopersicon esculentum Mill ...

African Journals Online (AJOL)

In order to investigate the effectiveness of a new method based on color image analysis and the Minolta SPAD-502 chlorophyll meter for the diagnosis of nitrogen deficiencies of tomato seedlings, a field experiment was conducted. In this study, five levels of nitrogen fertilization were established so as to induce nitrogen ...

Applications of nitrogen-alloyed stainless steels

Energy Technology Data Exchange (ETDEWEB)

Sundvall, J.; Olsson, J. [Avesta Sheffield AB (Sweden); Holmberg, B. [Avesta Welding AB (Sweden)

1999-07-01

A selected number of applications for different types of nitrogen-alloyed stainless steels are described. The applications and grades are based on how nitrogen improves different properties. Conventional austenitic grades of type 304 and 316 can be alloyed with nitrogen to increase the strength and to maintain the austenite stability after cold deformation when exposed to cryogenic temperatures. Such examples are presented. The addition of nitrogen to duplex grades of stainless steel such as 2205 improves the pitting resistance, among other things, and also enables faster reformation of the austenite in the heat affected zone. This means that heavy plate can be welded without pre-heating or post-weld heating. Such applications are covered. Modern highly alloyed austenitic stainless steels almost always contain nitrogen and all reasons for this are covered, i.e. to stabilise the austenite, to increase the strength, and to improve the pitting resistance. The increased strength is the characteristic exemplified the least, since the higher strength of duplex grades is well known, but examples on austenite stability and improved pitting resistance are presented. (orig.)

Manipulating vineyard nitrogen on a saline site: 1. Effect of nitrogen on growth, grape yield and nutrients of Vitis vinifera L. cv Shiraz.

Science.gov (United States)

Bell, Sally-Jean; Francis, I Leigh

2013-08-15

With increased prevalence of saline irrigation water applied to vines worldwide, the issue of appropriate nitrogen management is of concern. Different rates of nitrogen per vine as urea were applied to Shiraz vines on own roots over four seasons in a low-rainfall, saline growing environment. Application of nitrogen in the vineyard early in the season not only altered the vine nitrogen status but also increased some other elements in the petioles, notably chloride and sodium but also manganese and magnesium. In contrast, nitrogen application decreased petiole phosphorus. In comparison with the majority of nitrogen studies on non-saline sites, nitrogen-induced growth responses were restricted under the saline conditions in this study. While some changes in canopy density in response to nitrogen were observed, this did not affect light interception in the fruit zone. Yield responses were varied and could be related to the nutritional conditions under which bud development and flowering took place. This study demonstrated that current best practice guidelines, in terms of rate of nitrogen applied, for correcting a nitrogen deficiency on a non-saline site may not be appropriate for saline sites and that application of nitrogen can increase the potential for salt toxicity in vines. © 2013 Society of Chemical Industry.

Total Protein Content Determination of Microalgal Biomass by Elemental Nitrogen Analysis and a Dedicated Nitrogen-to-Protein Conversion Factor

Energy Technology Data Exchange (ETDEWEB)

Laurens, Lieve M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Olstad-Thompson, Jessica L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Templeton, David W [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2018-04-02

Accurately determining protein content is important in the valorization of algal biomass in food, feed, and fuel markets, where these values are used for component balance calculations. Conversion of elemental nitrogen to protein is a well-accepted and widely practiced method, but depends on developing an applicable nitrogen-to-protein conversion factor. The methodology reported here covers the quantitative assessment of the total nitrogen content of algal biomass and a description of the methodology that underpins the accurate de novo calculation of a dedicated nitrogen-to-protein conversion factor.

Leaf nitrogen remobilisation for plant development and grain filling.

Science.gov (United States)

Masclaux-Daubresse, C; Reisdorf-Cren, M; Orsel, M

2008-09-01

A major challenge of modern agriculture is to reduce the excessive input of fertilisers and, at the same time, to improve grain quality without affecting yield. One way to achieve this goal is to improve plant nitrogen economy through manipulating nitrogen recycling, and especially nitrogen remobilisation, from senescing plant organs. In this review, the contribution of nitrogen remobilisation efficiency (NRE) to global nitrogen use efficiency (NUE), and tools dedicated to the determination of NRE are described. An overall examination of the physiological, metabolic and genetic aspects of nitrogen remobilisation is presented.

21 May 2013 - Slovakian State Secretary, Ministry of Health V. Čislák signing the Guest Book with CERN Director-General R. Heuer; in the LHC tunnel at Point 2 with V. Senaj (Technology Department); in the ALICE experimental cavern with P. Chochula (Physics Department). M. Cirilli (Knowledge Transfer Group) present.

CERN Multimedia

Jean-Claude Gadmer

2013-01-01

21 May 2013 - Slovakian State Secretary, Ministry of Health V. Čislák signing the Guest Book with CERN Director-General R. Heuer; in the LHC tunnel at Point 2 with V. Senaj (Technology Department); in the ALICE experimental cavern with P. Chochula (Physics Department). M. Cirilli (Knowledge Transfer Group) present.

Numerical Simulation and Analysis on Liquid Nitrogen Spray Heat Exchanger

OpenAIRE

Wenjing Ding; Weiwei Shan; Zijuan; Wang; Chao He

2017-01-01

Liquid spray heat exchanger is the critical equipment of temperature regulating system by gaseous nitrogen which realizes the environment temperature in the range of -180 ℃~+180 ℃. Liquid nitrogen is atomized into smaller liquid drops through liquid nitrogen sprayer and then contacts with gaseous nitrogen to be cooled. By adjusting the pressure of liquid nitrogen and gaseous nitrogen, the flowrate of liquid nitrogen is changed to realize the required outlet temperature of heat exchanger. The ...

A tradeoff frontier for global nitrogen use and cereal production

International Nuclear Information System (INIS)

Mueller, Nathaniel D; West, Paul C; Gerber, James S; MacDonald, Graham K; Foley, Jonathan A; Polasky, Stephen

2014-01-01

Nitrogen fertilizer use across the world’s croplands enables high-yielding agricultural production, but does so at considerable environmental cost. Imbalances between nitrogen applied and nitrogen used by crops contributes to excess nitrogen in the environment, with negative consequences for water quality, air quality, and climate change. Here we utilize crop input-yield models to investigate how to minimize nitrogen application while achieving crop production targets. We construct a tradeoff frontier that estimates the minimum nitrogen fertilizer needed to produce a range of maize, wheat, and rice production levels. Additionally, we explore potential environmental consequences by calculating excess nitrogen along the frontier using a soil surface nitrogen balance model. We find considerable opportunity to achieve greater production and decrease both nitrogen application and post-harvest excess nitrogen. Our results suggest that current (circa 2000) levels of cereal production could be achieved with ∼50% less nitrogen application and ∼60% less excess nitrogen. If current global nitrogen application were held constant but spatially redistributed, production could increase ∼30%. If current excess nitrogen were held constant, production could increase ∼40%. Efficient spatial patterns of nitrogen use on the frontier involve substantial reductions in many high-use areas and moderate increases in many low-use areas. Such changes may be difficult to achieve in practice due to infrastructure, economic, or political constraints. Increases in agronomic efficiency would expand the frontier to allow greater production and environmental gains

Ubiquity of insect-derived nitrogen transfer to plants by endophytic insect-pathogenic fungi: an additional branch of the soil nitrogen cycle.

Science.gov (United States)

Behie, Scott W; Bidochka, Michael J

2014-03-01

The study of symbiotic nitrogen transfer in soil has largely focused on nitrogen-fixing bacteria. Vascular plants can lose a substantial amount of their nitrogen through insect herbivory. Previously, we showed that plants were able to reacquire nitrogen from insects through a partnership with the endophytic, insect-pathogenic fungus Metarhizium robertsii. That is, the endophytic capability and insect pathogenicity of M. robertsii are coupled so that the fungus acts as a conduit to provide insect-derived nitrogen to plant hosts. Here, we assess the ubiquity of this nitrogen transfer in five Metarhizium species representing those with broad (M. robertsii, M. brunneum, and M. guizhouense) and narrower insect host ranges (M. acridum and M. flavoviride), as well as the insect-pathogenic fungi Beauveria bassiana and Lecanicillium lecanii. Insects were injected with (15)N-labeled nitrogen, and we tracked the incorporation of (15)N into two dicots, haricot bean (Phaseolus vulgaris) and soybean (Glycine max), and two monocots, switchgrass (Panicum virgatum) and wheat (Triticum aestivum), in the presence of these fungi in soil microcosms. All Metarhizium species and B. bassiana but not L. lecanii showed the capacity to transfer nitrogen to plants, although to various degrees. Endophytic association by these fungi increased overall plant productivity. We also showed that in the field, where microbial competition is potentially high, M. robertsii was able to transfer insect-derived nitrogen to plants. Metarhizium spp. and B. bassiana have a worldwide distribution with high soil abundance and may play an important role in the ecological cycling of insect nitrogen back to plant communities.

Nitrogen deposition and traffic. State-of-the-art

International Nuclear Information System (INIS)

Teeuwisse, S.

2010-01-01

Nitrogen deposition is caused, among other things, by road traffic. This article addresses the relation between traffic and nitrogen deposition and the manner in which the contribution of traffic to nitrogen deposition can be quantified. [nl

Nitrogen-doped graphene by microwave plasma chemical vapor deposition

International Nuclear Information System (INIS)

Kumar, A.; Voevodin, A.A.; Paul, R.; Altfeder, I.; Zemlyanov, D.; Zakharov, D.N.; Fisher, T.S.

2013-01-01

Rapid synthesis of nitrogen-doped, few-layer graphene films on Cu foil is achieved by microwave plasma chemical vapor deposition. The films are doped during synthesis by introduction of nitrogen gas in the reactor. Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and scanning tunneling microscopy reveal crystal structure and chemical characteristics. Nitrogen concentrations up to 2 at.% are observed, and the limit is linked to the rigidity of graphene films on copper surfaces that impedes further nitrogen substitutions of carbon atoms. The entire growth process requires only a few minutes without supplemental substrate heating and offers a promising path toward large-scale synthesis of nitrogen-doped graphene films. - Highlights: ► Rapid synthesis of nitrogen doped few layer graphene on Cu foil. ► Defect density increment on 2% nitrogen doping. ► Nitrogen doped graphene is a good protection to the copper metallic surface

Nitrogen-doped graphene by microwave plasma chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Kumar, A., E-mail: kumar50@purdue.edu [Birck Nanotechnolgy Center, Purdue University, West Lafayette, IN 47907 (United States); Voevodin, A.A. [Birck Nanotechnolgy Center, Purdue University, West Lafayette, IN 47907 (United States); Materials and Manufacturing Directorate, Air Force Research Laboratory, WPAFB, OH 45433 (United States); Paul, R. [Birck Nanotechnolgy Center, Purdue University, West Lafayette, IN 47907 (United States); Altfeder, I. [Materials and Manufacturing Directorate, Air Force Research Laboratory, WPAFB, OH 45433 (United States); Zemlyanov, D.; Zakharov, D.N. [Birck Nanotechnolgy Center, Purdue University, West Lafayette, IN 47907 (United States); Fisher, T.S., E-mail: tsfisher@purdue.edu [Birck Nanotechnolgy Center, Purdue University, West Lafayette, IN 47907 (United States); Materials and Manufacturing Directorate, Air Force Research Laboratory, WPAFB, OH 45433 (United States)

2013-01-01

Rapid synthesis of nitrogen-doped, few-layer graphene films on Cu foil is achieved by microwave plasma chemical vapor deposition. The films are doped during synthesis by introduction of nitrogen gas in the reactor. Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and scanning tunneling microscopy reveal crystal structure and chemical characteristics. Nitrogen concentrations up to 2 at.% are observed, and the limit is linked to the rigidity of graphene films on copper surfaces that impedes further nitrogen substitutions of carbon atoms. The entire growth process requires only a few minutes without supplemental substrate heating and offers a promising path toward large-scale synthesis of nitrogen-doped graphene films. - Highlights: ► Rapid synthesis of nitrogen doped few layer graphene on Cu foil. ► Defect density increment on 2% nitrogen doping. ► Nitrogen doped graphene is a good protection to the copper metallic surface.

[Coupling effects of periodic rewatering after drought stress and nitrogen fertilizer on growth and water and nitrogen productivity of Coffea arabica].

Science.gov (United States)

Hao, Kun; Liu, Xiao Gang; Zhang, Yan; Han, Zhi Hui; Yu, Ning; Yang, Qi Liang; Liu, Yan Wei

2017-12-01

The effects of periodic rewatering after drought stress and nitrogen fertilizer on growth, yield, photosynthetic characteristics of leaves and water and nitrogen productivity of Coffea arabica (Katim P7963) were studied under different nitrogen application levels in 2.5 consecutive years. Irrigation (periodic rewatering after drought stress) and nitrogen were designed as two factors, with four modes of irrigation, namely, full irrigation (I F-F : 100%ET 0 +100%ET 0 , ET 0 was reference crop evapotranspiration), rewatering after light drought stress (I L-F : 80%ET 0 +100%ET 0 ), rewatering after moderate drought stress (I M-F : 60%ET 0 +100%ET 0 ) and rewatering after severe drought stress (I S-F : 40%ET 0 +100%ET 0 ), and three levels of nitrogen, namely, high nitrogen (N H : 750 kg N·hm -2 each time), middle nitrogen (N M : 500 kg N·hm -2 each time), low nitrogen (N L : 250 kg N·hm -2 each time), and nitrogen was equally applied for 4 times. The results showed that irrigation and nitrogen had significant effect on plant height, stem diameter, yield and water and nitrogen productivity of C. arabica, and plant height and stem diameter showed S-curve with the day ordinal number, and leaf photosynthesis decreased significantly under drought stress but most photosynthesis index recovered somewhat after rewatering. Compared with I F-F , I L-F increased dry bean yield by 6.9%, while I M-F and I S-F decreased dry bean yield by 15.2% and 38.5%, respectively; I L-F and I M-F increased water use efficiency by 18.8% and 6.0%, respectively, while I S-F decreased water use efficiency by 12.1%; I L-F increased nitrogen partial productivity by 6.1%, while I M-F and I S-F decreased nitrogen partial productivity by 14.0% and 36.0%, respectively. Compared with N H , N M increased dry bean yield and water use efficiency by 20.9% and 19.3%, while N L decreased dry bean yield and water use efficiency by 42.4% and 41.9%, respectively; N M and N L increased nitrogen partial

The nitrogen cascade from agricultural soils to the sea: modelling nitrogen transfers at regional watershed and global scales

OpenAIRE

Billen, Gilles; Garnier, Josette; Lassaletta, Luis

2013-01-01

The nitrogen cycle of pre-industrial ecosystems has long been remarkably closed, in spite of the high mobility of this element in the atmosphere and hydrosphere. Inter-regional and international commercial exchanges of agricultural goods, which considerably increased after the generalization of the use of synthetic nitrogen fertilizers, introduced an additional type of nitrogen mobility, which nowadays rivals the atmospheric and hydrological fluxes in intensity, and causes their enhancement a...

Swivel Joint For Liquid Nitrogen

Science.gov (United States)

Milner, James F.

1988-01-01

Swivel joint allows liquid-nitrogen pipe to rotate through angle of 100 degree with respect to mating pipe. Functions without cracking hard foam insulation on lines. Pipe joint rotates on disks so mechanical stress not transmitted to thick insulation on pipes. Inner disks ride on fixed outer disks. Disks help to seal pressurized liquid nitrogen flowing through joint.

The impact of agricultural land use on stream chemistry in the Middle Hills of the Himalayas, Nepal

Science.gov (United States)

Collins, Robert; Jenkins, Alan

1996-11-01

neutral throughout the storm event. The impacts of agricultural land use on streamwater chemistry are unlikely to lead to potentially damaging consequences for the aquatic biota at present or in the short-term future. The potential for acidity generation as a result of the high loads of nitrogenous fertilisers applied is apparently buffered by the land tillage practices, which promote higher weathering and so higher concentrations of base cations.

Variation in foliar nitrogen and albedo in response to nitrogen fertilization and elevated CO2

Science.gov (United States)

Haley F. Wicklein; Scott V. Ollinger; Mary E. Martin; David Y. Hollinger; Lucie C. Lepine; Michelle C. Day; Megan K. Bartlett; Andrew D. Richardson; Richard J. Norby

2012-01-01

Foliar nitrogen has been shown to be positively correlated with midsummer canopy albedo and canopy near infrared (NIR) reflectance over a broad range of plant functional types (e.g., forests, grasslands, and agricultural lands). To date, the mechanism(s) driving the nitrogen-albedo relationship have not been established, and it is unknown whether factors affecting...

Use of nitrogen stable isotope analysis to understand char nitrogen evolution during the fluidized-bed co-combustion of coal and sewage sludge

Energy Technology Data Exchange (ETDEWEB)

Ana Arenillas; Roberto Garcia; Chenggong Sun; Colin E. Snape; Angel H. Moreno; Fernando Rubiera; Jose J. Pis [University of Nottingham, Nottingham (United Kingdom). Nottingham Fuel and Energy Centre, School of Chemical, Environmental and Mining Engineering

2005-04-01

NOx emissions from sewage sludge combustion are a concern, because of the usually high nitrogen content of this fuel. The interactions during co-combustion in a fluidized-bed reactor of sewage sludge and a bituminous coal were evaluated, in relation to the nitrogen evolution during the combustion process. The nitrogen stable isotope measurements provide novel results regarding the tracing of nitrogen during combustion. Our preliminary results show that the co-combustion chars retain more nitrogen than expected, with the additional nitrogen being mainly derived from the sludge. Additional measurements are planned on the resultant co-combustion gases, to aid source apportionment of the NOx arising from coal/sewage interactions. 14 refs., 3 figs., 2 tabs.

Improvements to the Characterization of Organic Nitrogen Chemistry

Science.gov (United States)

Excess atmospheric nitrogen deposition can cause significant harmful effects to ecosystems. Organic nitrogen deposition can be an important contributor to the total nitrogen budget, contributing 10-30%, however there are large uncertainties in the chemistry and deposition of thes...

Carbon-nitrogen interactions and biomass partitioning of Carex rostrata grown at three levels of nitrogen supply

Energy Technology Data Exchange (ETDEWEB)

Saarinen, T [Helsinki Univ. (Finland). Dept. of Ecology and Systematics

1997-12-31

Biomass and production of vascular plants constitutes a major source of carbon input in peatlands. As rates of decomposition vary considerably with depth, the vertical distribution of biomass may substantially affect accumulation of carbon in peatlands. Therefore, allocation patterns between shoot and roots are particularly important when considering carbon balance of peatland ecosystems. The stimulatory effect of increasing atmospheric concentration of CO{sub 2} or photosynthesis may increase availability of carbon to most C3 plants. Availability of nitrogen may also alter both due to increased atmospheric deposition and changer in mineralisation rates associated with climate change. Most root-shoot partitioning models predict that allocation of biomass is dependent of the availability and uptake of carbon and nitrogen. A decrease in supply of carbon would favour allocation to shoots and a decrease in supply of nitrogen would increase allocation to roots. At a cellular level, non structural carbohydrates and free amino acids are thought to represent the biochemically available fraction of carbon and nitrogen, respectively. The aim of this work is study the long-term growth responses of Carex rostrata to changes in the availability of nitrogen. Special attention is paid to soluble sugars ant free amino acids, which may control partitioning of biomass. (10 refs.)

Carbon-nitrogen interactions and biomass partitioning of Carex rostrata grown at three levels of nitrogen supply

Energy Technology Data Exchange (ETDEWEB)

Saarinen, T. [Helsinki Univ. (Finland). Dept. of Ecology and Systematics

1996-12-31

Biomass and production of vascular plants constitutes a major source of carbon input in peatlands. As rates of decomposition vary considerably with depth, the vertical distribution of biomass may substantially affect accumulation of carbon in peatlands. Therefore, allocation patterns between shoot and roots are particularly important when considering carbon balance of peatland ecosystems. The stimulatory effect of increasing atmospheric concentration of CO{sub 2} or photosynthesis may increase availability of carbon to most C3 plants. Availability of nitrogen may also alter both due to increased atmospheric deposition and changer in mineralisation rates associated with climate change. Most root-shoot partitioning models predict that allocation of biomass is dependent of the availability and uptake of carbon and nitrogen. A decrease in supply of carbon would favour allocation to shoots and a decrease in supply of nitrogen would increase allocation to roots. At a cellular level, non structural carbohydrates and free amino acids are thought to represent the biochemically available fraction of carbon and nitrogen, respectively. The aim of this work is study the long-term growth responses of Carex rostrata to changes in the availability of nitrogen. Special attention is paid to soluble sugars ant free amino acids, which may control partitioning of biomass. (10 refs.)

Carbon and nitrogen isotope variations in tree-rings as records of perturbations in regional carbon and nitrogen cycles.

Science.gov (United States)

Bukata, Andrew R; Kyser, T Kurtis

2007-02-15

Increasing anthropogenic pollution from urban centers and fossil fuel combustion can impact the carbon and nitrogen cycles in forests. To assess the impact of twentieth century anthropogenic pollution on forested system carbon and nitrogen cycles, variations in the carbon and nitrogen isotopic compositions of tree-rings were measured. Individual annual growth rings in trees from six sites across Ontario and one in New Brunswick, Canada were used to develop site chronologies of tree-ring delta 15N and delta 13C values. Tree-ring 615N values were approximately 0.5% per hundred higher and correlated with contemporaneous foliar samples from the same tree, but not with delta 15N values of soil samples. Temporal trends in carbon and nitrogen isotopic compositions of these tree-rings are consistent with increasing anthropogenic influence on both the carbon and nitrogen cycles since 1945. Tree-ring delta 13C values and delta 15N values are correlated at both remote and urban-proximal sites, with delta 15N values decreasing since 1945 and converging on 1% per hundred at urban-proximal sites and decreasing but not converging on a single delta 15N value in remote sites. These results indicate that temporal trends in tree-ring nitrogen and carbon isotopic compositions record the regional extent of pollution.

Characterization of nitrogen-ion-implanted aluminium

International Nuclear Information System (INIS)

Rauschenbach, B.; Breuer, K.; Leonhardt, G.

1990-01-01

Aluminium has been implanted with nitrogen ions at different temperatures. The implanted samples have been characterized by Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and electron energy-loss spectroscopy (EELS). Deconvolution procedures are needed to separate the influence of the ion sputter profiling by AES and XPS from the nitrogen-ion-beam-induced effects. The chemical state of Al, N, O and C was identified by deconvolution of the measured spectra. In general, there were double-peak structures observed for N 1s and O 1s, identified as contributions from nitrides and weakly bound nitrogen, and oxides and weakly bound oxygen, respectively. Auger analysis confirms the influence of the nitrogen ion fluence on the shape of the concentration distribution. The influence of temperature on the chemical state of implanted aluminium and on the concentration distribution is discussed. (orig.)

Symbiosome-like intracellular colonization of cereals and other crop plants by nitrogen-fixing bacteria for reduced inputs of synthetic nitrogen fertilizers.

Science.gov (United States)

Cocking, Edward C; Stone, Philip J; Davey, Michael R

2005-09-01

It has been forecast that the challenge of meeting increased food demand and protecting environmental quality will be won or lost in maize, rice and wheat cropping systems, and that the problem of environmental nitrogen enrichment is most likely to be solved by substituting synthetic nitrogen fertilizers by the creation of cereal crops that are able to fix nitrogen symbiotically as legumes do. In legumes, rhizobia present intracellularly in membrane-bound vesicular compartments in the cytoplasm of nodule cells fix nitrogen endosymbiotically. Within these symbiosomes, membrane-bound vesicular compartments, rhizobia are supplied with energy derived from plant photosynthates and in return supply the plant with biologically fixed nitrogen, usually as ammonia. This minimizes or eliminates the need for inputs of synthetic nitrogen fertilizers. Recently we have demonstrated, using novel inoculation conditions with very low numbers of bacteria, that cells of root meristems of maize, rice, wheat and other major non-legume crops, such as oilseed rape and tomato, can be intracellularly colonized by the non-rhizobial, non-nodulating, nitrogen fixing bacterium,Gluconacetobacter diazotrophicus that naturally occurs in sugarcane.G. diazotrophicus expressing nitrogen fixing (nifH) genes is present in symbiosome-like compartments in the cytoplasm of cells of the root meristems of the target cereals and non-legume crop species, somewhat similar to the intracellular symbiosome colonization of legume nodule cells by rhizobia. To obtain an indication of the likelihood of adequate growth and yield, of maize for example, with reduced inputs of synthetic nitrogen fertilizers, we are currently determining the extent to which nitrogen fixation, as assessed using various methods, is correlated with the extent of systemic intracellular colonization byG. diazotrophicus, with minimal or zero inputs.

Biological nitrogen fixation in non-legume plants.

Science.gov (United States)

Santi, Carole; Bogusz, Didier; Franche, Claudine

2013-05-01

Nitrogen is an essential nutrient in plant growth. The ability of a plant to supply all or part of its requirements from biological nitrogen fixation (BNF) thanks to interactions with endosymbiotic, associative and endophytic symbionts, confers a great competitive advantage over non-nitrogen-fixing plants. Because BNF in legumes is well documented, this review focuses on BNF in non-legume plants. Despite the phylogenic and ecological diversity among diazotrophic bacteria and their hosts, tightly regulated communication is always necessary between the microorganisms and the host plant to achieve a successful interaction. Ongoing research efforts to improve knowledge of the molecular mechanisms underlying these original relationships and some common strategies leading to a successful relationship between the nitrogen-fixing microorganisms and their hosts are presented. Understanding the molecular mechanism of BNF outside the legume-rhizobium symbiosis could have important agronomic implications and enable the use of N-fertilizers to be reduced or even avoided. Indeed, in the short term, improved understanding could lead to more sustainable exploitation of the biodiversity of nitrogen-fixing organisms and, in the longer term, to the transfer of endosymbiotic nitrogen-fixation capacities to major non-legume crops.

Controlling nitrogen migration through micro-nano networks.

Science.gov (United States)

Cai, Dongqing; Wu, Zhengyan; Jiang, Jiang; Wu, Yuejin; Feng, Huiyun; Brown, Ian G; Chu, Paul K; Yu, Zengliang

2014-01-14

Nitrogen fertilizer unabsorbed by crops eventually discharges into the environment through runoff, leaching and volatilization, resulting in three-dimensional (3D) pollution spanning from underground into space. Here we describe an approach for controlling nitrogen loss, developed using loss control fertilizer (LCF) prepared by adding modified natural nanoclay (attapulgite) to traditional fertilizer. In the aqueous phase, LCF self-assembles to form 3D micro/nano networks via hydrogen bonds and other weak interactions, obtaining a higher nitrogen spatial scale so that it is retained by a soil filtering layer. Thus nitrogen loss is reduced and sufficient nutrition for crops is supplied, while the pollution risk of the fertilizer is substantially lowered. As such, self-fabrication of nano-material was used to manipulate the nitrogen spatial scale, which provides a novel and promising approach for the research and control of the migration of other micro-scaled pollutants in environmental medium.

Nitrogen vertical distribution by canopy reflectance spectrum in winter wheat

International Nuclear Information System (INIS)

Huang, W J; Yang, Q Y; Peng, D L; Huang, L S; Zhang, D Y; Yang, G J

2014-01-01

Nitrogen is a key factor for plant photosynthesis, ecosystem productivity and leaf respiration. Under the condition of nitrogen deficiency, the crop shows the nitrogen deficiency symptoms in the bottom leaves, while excessive nitrogen will affect the upper layer leaves first. Thus, timely measurement of vertical distribution of foliage nitrogen content is critical for growth diagnosis, crop management and reducing environmental impact. This study presents a method using bi-directional reflectance difference function (BRDF) data to invert foliage nitrogen vertical distribution. We developed upper-layer nitrogen inversion index (ULNI), middle-layer nitrogen inversion index (MLNI) and bottom-layer nitrogen inversion index (BLNI) to reflect foliage nitrogen inversion at upper layer, middle layer and bottom layer, respectively. Both ULNI and MLNI were made by the value of the ratio of Modified Chlorophyll Absorption Ration Index to the second Modified Triangular Vegetation Index (MCARI/MTVI2) referred to as canopy nitrogen inversion index (CNII) in this study at ±40° and ±50°, and at ±30° and ±40° view angles, respectively. The BLNI was composed by the value of nitrogen reflectance index (NRI) at ±20° and ±30° view angles. These results suggest that it is feasible to measure foliage nitrogen vertical-layer distribution in a large scale by remote sensing

Thermal and chemical durability of nitrogen-doped carbon nanotubes

International Nuclear Information System (INIS)

Liu Hao; Zhang Yong; Li Ruying; Sun Xueliang; Abou-Rachid, Hakima

2012-01-01

Nitrogen-doped carbon nanotubes (CN x tubes) with nitrogen content of 7.6 at.% are synthesized on carbon papers. Thermal and chemical stability of the nanotubes are investigated by thermogravimetric analysis, differential scanning calorimetry and X-ray photoelectron spectroscopy techniques. The results indicate that the nitrogen can be firmly kept in the nanotubes after annealing at 300 °C in air. Under an argon atmosphere, the nitrogen would not release until 670 °C, and half of the nitrogen incorporated is released after annealing at 700 °C for 30 min. Chemical stability investigation indicates that the nitrogen incorporated in the nanotubes is very stable under the thermal and acid environment comparable to working condition of proton exchange membrane (PEM) fuel cells. Profile of the nitrogen species inside the nanotubes reveals that graphite-like nitrogen releases slower than any other kind of nitrogen in the nanotubes during the chemical stability measurement. These CN x tubes synthesized by this simple chemical vapor deposition method are expected to be suitable for many applications, such as PEM fuel cells that work under both thermal and corrosive conditions and some other mild thermal environments.

Dissecting hormonal pathways in nitrogen-fixing rhizobium symbioses

NARCIS (Netherlands)

Zeijl, van Arjan

2017-01-01

Nitrogen is a key element for plant growth. To meet nitrogen demands, some plants establish an endosymbiotic relationship with nitrogen-fixing rhizobium or Frankia bacteria. This involves formation of specialized root lateral organs, named nodules. These nodules are colonized

Nitrogen oxides from combustion of nitrogen-containing polymers in waste-derived fuels

International Nuclear Information System (INIS)

Zevenhoven, R.; Kilpinen, P.; Hupa, M.; Elomaa, M.

2000-01-01

Usually, waste-derived fuels present nitrogen-containing fractions, which produce nitrogen oxides (NO) during combustion. This study was mainly concerned with poly amides (PA) (nylon), poly urethanes (PU), urea formaldehyde (UF) glue, sewage sludge and refuse-derived fuels (RDF). For control purposes, the authors chose a Polish sub-bituminous coal and a Finnish pine wood sample. An almost inverse trend between fuel nitrogen content and NO emissions was revealed through analysis of NO emissions at 850 Celsius, 1 bar, 7 per cent O 2 in N 2 . It was not possible to derive a clear correlation to the amount of ash generated by the samples. PU foam decomposed through a two-step process, as suggested by thermochromatography, and PA6-containing samples yielded epsilon-caprolactam as a major decomposition product. Important decomposition products from PU, PA6, PA6/PE, sewage sludge and UF glue samples were greenhouse gases as demonstrated by pyrolysis-gas chromatography/mass spectroscopy. The work was carried out at Abo Akademi University and University of Helsinki, Finland. 5 refs., 2 tabs., 3 figs

Variation in nitrogen use efficiencies on Dutch dairy farms

NARCIS (Netherlands)

Daatselaar, Co Hg; Reijs, Joan R.; Oenema, Jouke; Doornewaard, Gerben J.; Aarts, Frans

2015-01-01

BACKGROUND: On dairy farms, the input of nutrients including nitrogen is higher than the output in products such as milk and meat. This causes losses of nitrogen to the environment. One of the indicators for the losses of nitrogen is the nitrogen use efficiency. In the Dutch Minerals Policy

Nitrogen diffusion in zirconium nitride

International Nuclear Information System (INIS)

Desmaison, J.G.; Smeltzer, W.W.

1977-01-01

Nitrogen diffusion in polycrystalline ZrN/sub 0.71-0.79/ spheres, 60 and 90 μm diameter, was studied by the gas-solid exchange technique using 15 N as a tracer at a nitrogen pressure of 220 torr and 1000 to 1200 0 C. These specimens were characterized by chemical analyses, density, lattice parameter, and structural measurements. The tracer diffusion coefficient can be expressed as D* (cm 2 /S) = 3.0 x 10 -10 exp (-23,000/RT). This result, when compared to a previous determination obtained in the same conditions with 254 μm thick plates, confirms that nitrogen transport in this polycrystalline solid at temperatures less than 1200 0 C is associated with a short-circuit diffusion mechanism

Investigation on the Assimilation of Nitrogen by Maize Roots and the Transport of Some Major Nitrogen Compounds by Xylem Sap

DEFF Research Database (Denmark)

Ivanko, S.; Ingversen, J.

1971-01-01

The uptake and assimilation of nitrate and ammonia have been studied in Zea mays. Nitrogen-starved maize roots are capable of accumulating a potential capacity for nitrogen uptake and assimilation. Reestablishment of nitrogen supply leads to intense uptake, reaching 154 % of the reference variant...... level after 24 hours when nitrate is supplied, and 121 % when ammonia is supplied. After 24 hours the insoluble nitrogen fraction accounts for 80, 54 and 55 % of the total taken up in the PK + NO3-, PK + NH4+ and NPK variants respectively....

Human Decisions: Nitrogen Footprints and Environmental Effects

Science.gov (United States)

Leach, A. M.; Bleeker, A.; Galloway, J. N.; Erisman, J.

2012-12-01

Human consumption choices are responsible for growing losses of reactive nitrogen (Nr) to the environment. Once in the environment, Nr can cause a cascade of negative impacts such as smog, acid rain, coastal eutrophication, climate change, and biodiversity loss. Although all humans must consume nitrogen as protein, the food production process releases substantial Nr to the environment. This dilemma presents a challenge: how do we feed a growing population while reducing Nr? Although top-down strategies to reduce Nr losses (e.g., emissions controls) are necessary, the bottom-up strategies focusing on personal consumption patterns will be imperative to solve the nitrogen challenge. Understanding the effects of different personal choices on Nr losses and the environment is an important first step for this strategy. This paper will utilize information and results from the N-Calculator, a per capita nitrogen footprint model (www.N-Print.org), to analyze the impact of different food consumption patterns on a personal food nitrogen footprint and the environment. Scenarios will analyze the impact of the following dietary patterns on the average United States (28 kg Nr/cap/yr) food nitrogen footprint: 1) Consuming only the recommended protein as defined by the WHO and the USDA; 2) Reducing food waste by 50%; 3) Consuming a vegetarian diet; 4) Consuming a vegan diet; 5) Consuming a demitarian diet (replacing half of animal protein consumption with vegetable protein); 6) Substituting chicken (a more efficient animal protein) with beef (a less efficient animal protein); 7) Consuming sustainably-produced food; and 8) Using advanced wastewater treatment. Preliminary results suggest that widespread advanced wastewater treatment with nutrient removal technology and halving food waste would each reduce the US personal food nitrogen footprint by 13%. In addition, reducing protein consumption to the recommended levels would reduce the footprint by about 42%. Combining these measures

Nitrogen balance in grasses of the genus Brachiaria

International Nuclear Information System (INIS)

Loureiro, M. de F.

1985-01-01

A 15 N aided nitrogen balance experiment was performed in posts in the greenhouse to quantify the contribution of biological nitrogen fixation to four species of Brachiaria grow in two soils. The effects of adding molybdenum to the pots was also investigated. Among various methods for the analysis of total nitrogen in plant material and soil, a technique utilizing a pre-digestion with Devarda's alloy was found to be most efficient. In the nitrogen analyses the sample size and particle size were found to be factors limiting the precision of the analyses. In an analysis of the sources of error, the sampling of the soil was found to be the greatest source of variation on the nitrogen balance. (author)

Use of nitrogen-15 in soil-plant studies

International Nuclear Information System (INIS)

Sachdev, M.S.; Sachdev, P.; Subbiah, B.V.

1996-01-01

In this paper an overview of the selected work carried out in the country and elsewhere on the fertilizer nitrogen use efficiency, fate and balance-sheet, soil and fertilizer nitrogen transformations and biological nitrogen fixation using 15 N is given. 129 refs., 4 tabs

Nitrogen kinetics in aquatic plants in arctic Alaska

International Nuclear Information System (INIS)

McRoy, C.P.; Alexander, V.

1975-01-01

The kinetics of nitrogen in terms of ammonia uptake was measured for Carex aquatilis in arctic tundra ponds using 15 N tracer techniques. Nitrogen content of the leaves and primary productivity were measured throughout a growing season. The maximum uptake velocity for ammonia was 2.75 x 10 -2 % N/g dry weight per h with a Ksub(t) of 8.4-12.5 μgatoms/l. A second estimate of nitrogen uptake was made from the increase in nitrogen content throughout the season and from this a rate of 1.85 x 10 -2 % N/g dry weight per day was obtained for Carex aquatilis and 3.6 x 10 -2 % N/g dry weight per day for Arctophylla fulva. The total nitrogen concentration in the leaves was closely related to productivity, possible providing a new approach to productivity measurements for emergent vascular plants. Emergent vascular plants absorb ammonia across and translocate it to all portions of the plant. The ecological significance of this is considerable, since in many waters inorganic nitrogen content of sediment is much higher than that of the water surrounding the leaves and stems, and can provide a source of nitrogen

Root distribution pattern and nitrogen uptake of some wheat and triticale germplasms in relation to rates and methods of nitrogen application

International Nuclear Information System (INIS)

Meena, N.L.; Seth, Jagdish

1975-01-01

A field experiment was conducted under irrigated conditions with four germplasms viz. Triticale(70-2), and wheat varieties HD 4502(durum), Kalyan Sona and Moti (aestivums) at the Indian Agricultural Research Institute Farm, New Delhi, during rabi season of 1972-73. The treatments comprised of three rates of nitrogen viz. 0,60 and 120 kg/ha and two methods of nitrogen application viz. (1) soil + foliar and (2) soil. The root distribution of the four germplasms, studied by 32 P injection technique was increased both vertically and horizontally with the addition of nitrogen. Root distribution of triticale was observed to be deep and spreading in habit, while durum proved to be shallow rooted and compact in nature. The total uptake of nitrogen was significantly increased with higher rates of nitrogen in all the germplasms. The maximum uptake of nitrogen was observed in the durum wheat. (author)

Studies on nitrogen retention in growing pigs

DEFF Research Database (Denmark)

Thorbek, G; Henckel, S; Chwalibog, André

1987-01-01

Nitrogen retention (RN) was measured in 60 barrows of Danish Landrace and a total of 470 balance periods was carried out during the growth period from 20 to 85 kg live weight. In the first serie (Expt A) six different feed compounds of high biological value (HBV) were fed to 48 barrows, while...... in the second serie (Expt B) 12 barrows were measured on feed compounds of HBV or low biological value (LBV). Three different levels of gross energy were used in Expt B. Individual differences of 10-20% in the pigs capability for nitrogen retention were observed. Nitrogen retention increased from 12 to 21 g N....../d on the HBV-compounds and was not influenced by increasing nitrogen or energy intake. Nitrogen retention was curvilinear in relation to metabolic live weight (kg0.75) in both series. A parabolic function on kg0.75 gave the best fit to the data with the following regression equations: Expt A + B: RN, g/d = 1...

Nitrogen dioxide exposures inside ice skating rinks.

Science.gov (United States)

Brauer, M; Spengler, J D

1994-01-01

OBJECTIVES. The common operation of fuel-powered resurfacing equipment in enclosed ice skating rinks has the potential for producing high concentrations of carbon monoxide and nitrogen dioxide. Exposures to these gaseous combustion products may adversely affect the health of those inside the rink. Little information is available on pollutant concentrations under normal operating conditions. METHODS. One-week average nitrogen dioxide concentrations in 70 northeastern US rinks were measured with passive samplers during normal winter season conditions. RESULTS. The median nitrogen dioxide level inside rinks was 180 ppb, more than 10 times higher than the median outdoor concentration. One-week average nitrogen dioxide concentrations above 1000 ppb were measured in 10% of the rinks. CONCLUSIONS. Considering that short-term peak concentrations were likely to have reached two to five times the measured 1-week averages, our results suggest that nitrogen dioxide levels were well above short-term air quality guidelines and constitute a public health concern of considerable magnitude. PMID:8129060

Utilization of nitrogen fixing trees

Energy Technology Data Exchange (ETDEWEB)

Brewbaker, J.L.; Beldt, R. van den; MacDicken, K.; Budowski, G.; Kass, D.C.L.; Russo, R.O.; Escalante, G.; Herrera, R.; Aranguren, J.; Arkcoll, D.B.; Doebereinger, J. (cord.)

1983-01-01

Six papers from the symposium are noted. Brewbaker, J.L., Beldt, R. van den, MacDicken, K. Fuelwood uses and properties of nitrogen-fixing trees, pp 193-204, (Refs. 15). Includes a list of 35 nitrogen-fixing trees of high fuelwood value. Budowski, G.; Kass, D.C.L.; Russo, R.O. Leguminous trees for shade, pp 205-222, (Refs. 68). Escalante, G., Herrera, R., Aranguren, J.; Nitrogen fixation in shade trees (Erythrina poeppigiana) in cocoa plantations in northern Venezuela, pp 223-230, (Refs. 13). Arkcoll, D.B.; Some leguminous trees providing useful fruits in the North of Brazil, pp 235-239, (Refs. 13). This paper deals with Parkia platycephala, Pentaclethra macroloba, Swartzia sp., Cassia leiandra, Hymenaea courbaril, dipteryz odorata, Inga edulis, I. macrophylla, and I. cinnamonea. Baggio, A.J.; Possibilities of the use of Gliricidia sepium in agroforestry systems in Brazil, pp 241-243; (Refs. 15). Seiffert, N.F.; Biological nitrogen and protein production of Leucaena cultivars grown to supplement the nutrition of ruminants, pp 245-249, (Refs. 14). Leucaena leucocephala cv. Peru, L. campina grande (L. leucocephala), and L. cunningham (L. leucocephalae) were promising for use as browse by beef cattle in central Brazil.

Toward a mechanistic modeling of nitrogen limitation on vegetation dynamics.

Science.gov (United States)

Xu, Chonggang; Fisher, Rosie; Wullschleger, Stan D; Wilson, Cathy J; Cai, Michael; McDowell, Nate G

2012-01-01

Nitrogen is a dominant regulator of vegetation dynamics, net primary production, and terrestrial carbon cycles; however, most ecosystem models use a rather simplistic relationship between leaf nitrogen content and photosynthetic capacity. Such an approach does not consider how patterns of nitrogen allocation may change with differences in light intensity, growing-season temperature and CO(2) concentration. To account for this known variability in nitrogen-photosynthesis relationships, we develop a mechanistic nitrogen allocation model based on a trade-off of nitrogen allocated between growth and storage, and an optimization of nitrogen allocated among light capture, electron transport, carboxylation, and respiration. The developed model is able to predict the acclimation of photosynthetic capacity to changes in CO(2) concentration, temperature, and radiation when evaluated against published data of V(c,max) (maximum carboxylation rate) and J(max) (maximum electron transport rate). A sensitivity analysis of the model for herbaceous plants, deciduous and evergreen trees implies that elevated CO(2) concentrations lead to lower allocation of nitrogen to carboxylation but higher allocation to storage. Higher growing-season temperatures cause lower allocation of nitrogen to carboxylation, due to higher nitrogen requirements for light capture pigments and for storage. Lower levels of radiation have a much stronger effect on allocation of nitrogen to carboxylation for herbaceous plants than for trees, resulting from higher nitrogen requirements for light capture for herbaceous plants. As far as we know, this is the first model of complete nitrogen allocation that simultaneously considers nitrogen allocation to light capture, electron transport, carboxylation, respiration and storage, and the responses of each to altered environmental conditions. We expect this model could potentially improve our confidence in simulations of carbon-nitrogen interactions and the vegetation

Toward a Mechanistic Modeling of Nitrogen Limitation on Vegetation Dynamics

Science.gov (United States)

Xu, Chonggang; Fisher, Rosie; Wullschleger, Stan D.; Wilson, Cathy J.; Cai, Michael; McDowell, Nate G.

2012-01-01

Nitrogen is a dominant regulator of vegetation dynamics, net primary production, and terrestrial carbon cycles; however, most ecosystem models use a rather simplistic relationship between leaf nitrogen content and photosynthetic capacity. Such an approach does not consider how patterns of nitrogen allocation may change with differences in light intensity, growing-season temperature and CO2 concentration. To account for this known variability in nitrogen-photosynthesis relationships, we develop a mechanistic nitrogen allocation model based on a trade-off of nitrogen allocated between growth and storage, and an optimization of nitrogen allocated among light capture, electron transport, carboxylation, and respiration. The developed model is able to predict the acclimation of photosynthetic capacity to changes in CO2 concentration, temperature, and radiation when evaluated against published data of Vc,max (maximum carboxylation rate) and Jmax (maximum electron transport rate). A sensitivity analysis of the model for herbaceous plants, deciduous and evergreen trees implies that elevated CO2 concentrations lead to lower allocation of nitrogen to carboxylation but higher allocation to storage. Higher growing-season temperatures cause lower allocation of nitrogen to carboxylation, due to higher nitrogen requirements for light capture pigments and for storage. Lower levels of radiation have a much stronger effect on allocation of nitrogen to carboxylation for herbaceous plants than for trees, resulting from higher nitrogen requirements for light capture for herbaceous plants. As far as we know, this is the first model of complete nitrogen allocation that simultaneously considers nitrogen allocation to light capture, electron transport, carboxylation, respiration and storage, and the responses of each to altered environmental conditions. We expect this model could potentially improve our confidence in simulations of carbon-nitrogen interactions and the vegetation feedbacks

Toward a mechanistic modeling of nitrogen limitation on vegetation dynamics.

Directory of Open Access Journals (Sweden)

Chonggang Xu

Full Text Available Nitrogen is a dominant regulator of vegetation dynamics, net primary production, and terrestrial carbon cycles; however, most ecosystem models use a rather simplistic relationship between leaf nitrogen content and photosynthetic capacity. Such an approach does not consider how patterns of nitrogen allocation may change with differences in light intensity, growing-season temperature and CO(2 concentration. To account for this known variability in nitrogen-photosynthesis relationships, we develop a mechanistic nitrogen allocation model based on a trade-off of nitrogen allocated between growth and storage, and an optimization of nitrogen allocated among light capture, electron transport, carboxylation, and respiration. The developed model is able to predict the acclimation of photosynthetic capacity to changes in CO(2 concentration, temperature, and radiation when evaluated against published data of V(c,max (maximum carboxylation rate and J(max (maximum electron transport rate. A sensitivity analysis of the model for herbaceous plants, deciduous and evergreen trees implies that elevated CO(2 concentrations lead to lower allocation of nitrogen to carboxylation but higher allocation to storage. Higher growing-season temperatures cause lower allocation of nitrogen to carboxylation, due to higher nitrogen requirements for light capture pigments and for storage. Lower levels of radiation have a much stronger effect on allocation of nitrogen to carboxylation for herbaceous plants than for trees, resulting from higher nitrogen requirements for light capture for herbaceous plants. As far as we know, this is the first model of complete nitrogen allocation that simultaneously considers nitrogen allocation to light capture, electron transport, carboxylation, respiration and storage, and the responses of each to altered environmental conditions. We expect this model could potentially improve our confidence in simulations of carbon-nitrogen interactions and the

Do lichens have "memory" of their native nitrogen environment?

Science.gov (United States)

Munzi, Silvana; Loppi, Stefano; Cruz, Cristina; Branquinho, Cristina

2011-02-01

This study aimed to deepen the knowledge about intraspecific mechanisms regulating nitrogen tolerance in lichens to wet nitrogen deposition. Thalli of the nitrophilous lichen Xanthoria parietina were collected from environments with different nitrogen availabilities and immersed in 80 mL of ammonium sulphate (NH₄)₂SO₄ solutions with distinct concentrations (0, 0.025, 0.05 and 0.25 M) for 5 h per day during 3 days in a week. After each soaking event, lichens were air dried. After each treatment, maximal PSII efficiency, localization of ammonium ions, concentrations of K+ and Mg²+ and thalli buffer capacity were determined. Our results show that lichens are marked by their native nitrogen environment, since there were important differences between the physiological responses of X. parietina thalli previously grown in an area with high nitrogen deposition (nitrogen emissions of ca. 13,000 t/year) and those previously grown in an unpolluted area (nitrogen emissions of ca. 500 t/year). Greater N availability seems to enable X. parietina to cope better with the effects of nitrogen pollution.

Whole-ecosystem nitrogen effects research in Europe

International Nuclear Information System (INIS)

Sullivan, T.J.

1993-01-01

There has been an enormous increase during the past few years in the amount of research being conducted in Europe on the effects of atmospheric deposition of nitrogen on aquatic, and especially terrestrial, ecosystems. Nitrogen deposition increases the emissions of N 2 O from forest soils and may decrease CH 4 uptake. Both increased N 2 O production and decreased CH 4 consumption would increase the concentration of greenhouse gases in the atmosphere. Thus there are important linkages between nitrogen deposition (and consequent ecosystem effects) and the release of greenhouse gases that have been implicated in potential global climate change. This paper summarises some of the European research that has been carried out in recent years. The experimental approach has shifted heavily into whole-ecosystem experimental manipulations, which are being conducted across gradients of atmospheric deposition and other environmental factors. Manipulations are focused primarily on coniferous forest ecosystems and involve increasing ambient deposition of sulfur and nitrogen; excluding ambient deposition via the construction of roofs over entire forested plots or catchments; and manipulating climatic factors, especially water availability. Experiments are designed to continue for long periods (i.e., 5-10 years) and are augmented by detailed, process-level studies at the manipulation sites. Results of the broad-scale and detailed studies are being used to build, test, and validate mathematical models that simulate nitrogen processing, nutrient cycling, and water regulation in coniferous forest ecosystems under varying depositional and climatic regimes. Ultimately, these models will be used to predict nitrogen saturation, estimate the critical loads of nitrogen for European forests, and specify emission controls needed to protect European forests and surface waters from the detrimental effects of excess nitrogen deposition. 19 refs., 1 fig., 2 photos

Assimilation of 15N-labelled urea nitrogen and ammonium nitrate nitrogen by plants in case of root and non-root fertilization

International Nuclear Information System (INIS)

Muravin, Eh.A.; Kozhemyachko, V.A.; Vernichenko, I.V.

1974-01-01

Assimilation of 15 N labeled urea and ammonium nitrate in root and foliar application by spring wheat and barley has been studied during 1970-1973 period in a series of vegetative experiments at the Department of Agrochemistry, Timiryazev Agricultural Academy, and at D.N. Pryanishnikov Experimental Agrochemical Station. Additional fertilizer nitrogen applied at later ontogenesis stages (flowering and milky ripeness) is utilized mostly for protein synthesis in developing grains, thus leading to a significant increase in the relative grain protein content. A transfer of a part of nitrogen from the main ortion of fertilizer at later stages of nitrition results, at the same time, in a lower yield. Nitrogen utilization degree of urea and ammonium nitrate, when introduced before sowing or at the flowering stage is similar but in the latter case, however, additional assimilation of soil nitrogen is lower. The assimilation rate of nitrogen in root application is the lower the later the fertilizer is applied. When ammonium nitrate is additionally applied as nutrition to barley at the milky ripeness stage, ammonia and nitrate nitrogen are assimilated at the same rate and to the same extent but ammonia nitrogen is more rapidly used for protein synthesis and the rate of its transfer to the developing grains is higher. The rate of nitrogen assimilation at plant is much higher in foliar than in root application. Wheat utilizes more urea nitrogen at the flowering stage when root application is used but at the milky ripeness stage foliar application is more effective

Endogenous Losses of Nitrogen and Protein Requirement for ...

African Journals Online (AJOL)

Four fistulated and four intact West African dwarf wether sheep, maintained on hay and concentrate supplements were used for a study of metabolic faecal nitrogen (MEN) and endogenous urinary nitrogen (EUN). The composition of the faecal losses was examined. The values obtained enabled calculation of nitrogen ...

40 CFR 52.1876 - Control strategy: Nitrogen dioxide.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Nitrogen dioxide. 52.1876 Section 52.1876 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...: Nitrogen dioxide. (a) The condition to EPA's approval of the oxides of nitrogen State Implementation Plan...

Remarkable activity of nitrogen-doped hollow carbon spheres encapsulated Cu on synthesis of dimethyl carbonate: Role of effective nitrogen

Science.gov (United States)

Li, Haixia; Zhao, Jinxian; Shi, Ruina; Hao, Panpan; Liu, Shusen; Li, Zhong; Ren, Jun

2018-04-01

A critical aspect in the improvement of the catalytic performance of Cu-based catalysts for the synthesis of dimethyl carbonate (DMC) is the development of an appropriate support. In this work, nitrogen-doped hollow carbon spheres (NHCSs), with 240 nm average diameter, 17 nm shell thickness, uniform mesoporous structure and a specific surface area of 611 m2 g-1, were prepared via a two-step Stӧber method. By varying the quantity of nitrogen-containing phenols used in the preparation it has been possible to control the nitrogen content and, consequently, the sphericity of the NHCSs. It was found that perfect spheres were obtained for nitrogen contents below 5.4 wt.%. The catalysts (Cu@NHCSs) were prepared by the hydrothermal impregnation method. The catalytic activity towards DMC synthesis was notably enhanced due to the immobilization effect on Cu particles and the enhanced electron transfer effect exercised by the effective nitrogen species, including pyridinic-N and graphitic-N. When the average size of the copper nanoparticles was 7.4 nm and the nitrogen content was 4.0 wt.%, the values of space-time yield of DMC and of turnover frequency (TOF) reached 1528 mg/(g h) and 11.0 h-1, respectively. The TOF value of Cu@NHCSs was 6 times higher than non-doped Cu@Carbon (2.1 h-1). The present work introduces the potential application of nitrogen-doped carbon materials and presents a novel procedure for the preparation of catalysts for DMC synthesis.