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Sample records for present-day mexican-mestizos revealed

  1. The rs3857059 variant of the SNCA gene is associated with Parkinson's disease in Mexican Mestizos.

    PubMed

    García, S; Chavira-Hernández, G; Gallegos-Arreola, M P; Dávila-Maldonado, L; García Martínez, F; Montes Almanza, L A; Palma-Flores, C; Mondragón-Terán, P; Alcaraz Estrada, S L; López-Hernández, L B

    2016-06-01

    Among the candidate genes for Parkinson's disease (PD), SNCA has replicated association in different populations. Besides other known mutations in the SNCA gene, the rs3857059 variant has also been linked to various neurodegenerative disorders. Therefore, the aim of the present study was to search for association of this variant and sporadic PD in Mexican Mestizo patients. A case-control study was performed including 241 individuals, 106 patients, and 135 healthy controls. Genotyping was performed using real-time PCR. The rs3857059 variant demonstrated an association with PD in Mexican Mestizos (OR = 2.40, CI, 1.1 to 5.1, p = 0.02) under the recessive model. In addition, a gender effect was found for the GG genotype in females (OR = 1.31, CI, 1.01 to 1.7, p = 0.037). This is the first study to confirm an association of the rs3857059 variant with PD and also to show a gender effect. Our data contribute to the elucidation of the link between rs3857059 and susceptibility to PD observed in the Mexican Mestizo population. PMID:27332068

  2. Molecular study of VWF gene from Mexican Mestizo patients with von Willebrand disease, and the finding of three new mutations.

    PubMed

    Melo-Nava, Brenda M; Benítez, Herminia; Palacios, J Jorge; Nieva, Beatriz; Arenas, Diego; Jaloma-Cruz, A Rebeca; Navarrete, Carmen; Salamanca, Fabio; Peñaloza, Rosenda

    2007-01-01

    To investigate the origin of von Willebrand disease in Mexican Mestizo population, we analyzed exons 18, 19, 20, 28, 45, and 52 of the VWF gene from 34 Mexican Mestizo index cases, 28 of them affected but not related, using DNA amplification by polymerase chain reaction and direct sequencing. We found three novel mutations: E1447Q in one patient with type 1; P2781S in one patient with type 2M; and P812L in another type 1/2N patient. These mutations were not found in 100 normal alleles. Moreover, we found other mutations previously reported in the literature; one of them (G1609R) was the most frequent (6/28) in patients with VWD type 2A. This is the first molecular study in a Mexican group that has a particular mixture of Indigenous, Caucasian, and African genes. PMID:17681836

  3. Mitogenomes from The 1000 Genome Project Reveal New Near Eastern Features in Present-Day Tuscans

    PubMed Central

    Pardo-Seco, Jacobo; Amigo, Jorge; Martinón-Torres, Federico

    2015-01-01

    Background Genetic analyses have recently been carried out on present-day Tuscans (Central Italy) in order to investigate their presumable recent Near East ancestry in connection with the long-standing debate on the origins of the Etruscan civilization. We retrieved mitogenomes and genome-wide SNP data from 110 Tuscans analyzed within the context of The 1000 Genome Project. For phylogeographic and evolutionary analysis we made use of a large worldwide database of entire mitogenomes (>26,000) and partial control region sequences (>180,000). Results Different analyses reveal the presence of typical Near East haplotypes in Tuscans representing isolated members of various mtDNA phylogenetic branches. As a whole, the Near East component in Tuscan mitogenomes can be estimated at about 8%; a proportion that is comparable to previous estimates but significantly lower than admixture estimates obtained from autosomal SNP data (21%). Phylogeographic and evolutionary inter-population comparisons indicate that the main signal of Near Eastern Tuscan mitogenomes comes from Iran. Conclusions Mitogenomes of recent Near East origin in present-day Tuscans do not show local or regional variation. This points to a demographic scenario that is compatible with a recent arrival of Near Easterners to this region in Italy with no founder events or bottlenecks. PMID:25786119

  4. Admixture and genetic relationships of Mexican Mestizos regarding Latin American and Caribbean populations based on 13 CODIS-STRs.

    PubMed

    Salazar-Flores, J; Zuñiga-Chiquette, F; Rubi-Castellanos, R; Álvarez-Miranda, J L; Zetina-Hérnandez, A; Martínez-Sevilla, V M; González-Andrade, F; Corach, D; Vullo, C; Álvarez, J C; Lorente, J A; Sánchez-Diz, P; Herrera, R J; Cerda-Flores, R M; Muñoz-Valle, J F; Rangel-Villalobos, H

    2015-02-01

    Short tandem repeats (STRs) of the combined DNA index system (CODIS) are probably the most employed markers for human identification purposes. STR databases generated to interpret DNA profiles are also helpful for anthropological purposes. In this work, we report admixture, population structure, and genetic relationships of Mexican Mestizos with respect to Latin American and Caribbean populations based on 13 CODIS-STRs. In addition, new STR population data were included from Tijuana, Baja California (Northwest, Mexico), which represents an interesting case of elevated genetic flow as a bordering city with the USA. Inter-population analyses included CODIS-STR data from 11 Mexican Mestizo, 12 Latin American and four Caribbean populations, in addition to European, Amerindian, and African genetic pools as ancestral references. We report allele frequencies and statistical parameters of forensic interest (PD, PE, Het, PIC, typical PI), for 15 STRs in Tijuana, Baja California. This Mexican border city was peculiar by the increase of African ancestry, and by presenting three STRs in Hardy-Weinberg disequilibrium, probably explained by recurrent gene flow. The Amerindian ancestry in Central and Southeast of Mexico was the greatest in Latin America (50.9-68.6%), only comparable with the North of Central America and Ecuador (48.8-56.4%), whereas the European ancestry was prevalent in South America (66.7-75%). The African ancestry in Mexico was the smallest (2.2-6.3%) in Latin America (≥ 2.6%), particularly regarding Brazil (21%), Honduras (62%), and the Caribbean (43.2-65.2%). CODIS-STRs allowed detecting significant population structure in Latin America based on greater presence of European, Amerindian, and African ancestries in Central/South America, Mexican Mestizos, and the Caribbean, respectively. PMID:25435058

  5. Calpain-10 gene polymorphisms and risk of type 2 diabetes mellitus in Mexican mestizos.

    PubMed

    Picos-Cárdenas, V J; Sáinz-González, E; Miliar-García, A; Romero-Zazueta, A; Quintero-Osuna, R; Leal-Ugarte, E; Peralta-Leal, V; Meza-Espinoza, J P

    2015-01-01

    The calpain-10 gene is expressed primarily in tissues important in glucose metabolism; thus, some of its polymorphisms have been associated with type 2 diabetes. In this study, we examined the association between the calpain-10 single-nucleotide polymorphism (SNP)-43, SNP-19, and SNP-63 and type 2 diabetes in Mexican mestizos. We included 211 patients and 152 non-diabetic subjects. Polymerase chain reaction was used to identify alleles. We compared allele, genotype, haplotype, and diplotype frequencies between both groups and used the chi-square test to calculate the risk. The allele frequency of SNP-43 allele 1 was 70% in controls and 72% in patients; the GG, GA, and AA genotype frequencies were 48.7, 42.8, and 8.5% in controls and 51.2, 41.7, and 7.1% in patients, respectively. For SNP- 19, the prevalence of allele 1 (2R) was 32% in controls and 39% in patients. In controls, homozygosity (2R/2R) was 10.5%, heterozygosity was 42.8%, and 3R/3R was 46.7%; in cases, these values were 13.3, 50.7, and 36.0%, respectively. For SNP-63, the frequency of allele 1 was 87% in controls and 83% in patients; genotype frequencies in controls were 75.7% (CC), 23% (CT), and 1.3% (TT), and were 69.7, 27.5, and 2.8%, respectively for the cases. Genotype distributions were consistent with Hardy-Weinberg equilibrium. No significant intergroup differences for allele, genotype, haplotype, or diplotype frequencies were observed. We found no association between these polymorphisms and diabetes. However, our sample size was small, so the role of calpain-10 risk alleles should be further examined. PMID:25867367

  6. Ancient DNA reveals matrilineal continuity in present-day Poland over the last two millennia.

    PubMed

    Juras, Anna; Dabert, Miroslawa; Kushniarevich, Alena; Malmström, Helena; Raghavan, Maanasa; Kosicki, Jakub Z; Metspalu, Ene; Willerslev, Eske; Piontek, Janusz

    2014-01-01

    While numerous ancient human DNA datasets from across Europe have been published till date, modern-day Poland in particular, remains uninvestigated. Besides application in the reconstruction of continent-wide human history, data from this region would also contribute towards our understanding of the history of the Slavs, whose origin is hypothesized to be in East or Central Europe. Here, we present the first population-scale ancient human DNA study from the region of modern-day Poland by establishing mitochondrial DNA profiles for 23 samples dated to 200 BC - 500 AD (Roman Iron Age) and for 20 samples dated to 1000-1400 AD (Medieval Age). Our results show that mitochondrial DNA sequences from both periods belong to haplogroups that are characteristic of contemporary West Eurasia. Haplotype sharing analysis indicates that majority of the ancient haplotypes are widespread in some modern Europeans, including Poles. Notably, the Roman Iron Age samples share more rare haplotypes with Central and Northeast Europeans, whereas the Medieval Age samples share more rare haplotypes with East-Central and South-East Europeans, primarily Slavic populations. Our data demonstrates genetic continuity of certain matrilineages (H5a1 and N1a1a2) in the area of present-day Poland from at least the Roman Iron Age until present. As such, the maternal gene pool of present-day Poles, Czechs and Slovaks, categorized as Western Slavs, is likely to have descended from inhabitants of East-Central Europe during the Roman Iron Age. PMID:25337992

  7. Contribution of Common Genetic Variation to the Risk of Type 2 Diabetes in the Mexican Mestizo Population

    PubMed Central

    Gamboa-Meléndez, Marco Alberto; Huerta-Chagoya, Alicia; Moreno-Macías, Hortensia; Vázquez-Cárdenas, Paola; Ordóñez-Sánchez, María Luisa; Rodríguez-Guillén, Rosario; Riba, Laura; Rodríguez-Torres, Maribel; Guerra-García, María Teresa; Guillén-Pineda, Luz Elizabeth; Choudhry, Shweta; del Bosque-Plata, Laura; Canizales-Quinteros, Samuel; Pérez-Ortiz, Gustavo; Escobedo-Aguirre, Fernando; Parra, Adalberto; Lerman-Garber, Israel; Aguilar-Salinas, Carlos Alberto; Tusié-Luna, María Teresa

    2012-01-01

    Several studies have identified nearly 40 different type 2 diabetes susceptibility loci, mainly in European populations, but few of them have been evaluated in the Mexican population. The aim of this study was to examine the extent to which 24 common genetic variants previously associated with type 2 diabetes are associated in Mexican Mestizos. Twenty-four single nucleotide polymorphisms (SNPs) in or near genes (KCNJ11, PPARG, TCF7L2, SLC30A8, HHEX, CDKN2A/2B, CDKAL1, IGF2BP2, ARHGEF11, JAZF1, CDC123/CAMK1D, FTO, TSPAN8/LGR5, KCNQ1, THADA, ADAMTS9, NOTCH2, NXPH1, RORA, UBQLNL, and RALGPS2) were genotyped in Mexican Mestizos. A case-control association study comprising 1,027 type 2 diabetic individuals and 990 control individuals was conducted. To account for population stratification, a panel of 104 ancestry-informative markers was analyzed. Association to type 2 diabetes was found for rs13266634 (SLC30A8), rs7923837 (HHEX), rs10811661 (CDKN2A/2B), rs4402960 (IGF2BP2), rs12779790 (CDC123/CAMK1D), and rs2237892 (KCNQ1). In addition, rs7754840 (CDKAL1) was associated in the nonobese type 2 diabetic subgroup, and for rs7903146 (TCF7L2), association was observed for early-onset type 2 diabetes. Lack of association for the rest of the variants may have resulted from insufficient power to detect smaller allele effects. PMID:22923468

  8. Ancient DNA Reveals Matrilineal Continuity in Present-Day Poland over the Last Two Millennia

    PubMed Central

    Juras, Anna; Dabert, Miroslawa; Kushniarevich, Alena; Malmström, Helena; Raghavan, Maanasa; Kosicki, Jakub Z.; Metspalu, Ene; Willerslev, Eske; Piontek, Janusz

    2014-01-01

    While numerous ancient human DNA datasets from across Europe have been published till date, modern-day Poland in particular, remains uninvestigated. Besides application in the reconstruction of continent-wide human history, data from this region would also contribute towards our understanding of the history of the Slavs, whose origin is hypothesized to be in East or Central Europe. Here, we present the first population-scale ancient human DNA study from the region of modern-day Poland by establishing mitochondrial DNA profiles for 23 samples dated to 200 BC – 500 AD (Roman Iron Age) and for 20 samples dated to 1000–1400 AD (Medieval Age). Our results show that mitochondrial DNA sequences from both periods belong to haplogroups that are characteristic of contemporary West Eurasia. Haplotype sharing analysis indicates that majority of the ancient haplotypes are widespread in some modern Europeans, including Poles. Notably, the Roman Iron Age samples share more rare haplotypes with Central and Northeast Europeans, whereas the Medieval Age samples share more rare haplotypes with East-Central and South-East Europeans, primarily Slavic populations. Our data demonstrates genetic continuity of certain matrilineages (H5a1 and N1a1a2) in the area of present-day Poland from at least the Roman Iron Age until present. As such, the maternal gene pool of present-day Poles, Czechs and Slovaks, categorized as Western Slavs, is likely to have descended from inhabitants of East-Central Europe during the Roman Iron Age. PMID:25337992

  9. High resolution human leukocyte antigen (HLA) class I and class II allele typing in Mexican mestizo women with sporadic breast cancer: case-control study

    PubMed Central

    2009-01-01

    Background The development of breast cancer is multifactorial. Hormonal, environmental factors and genetic predisposition, among others, could interact in the presentation of breast carcinoma. Human leukocyte antigen (HLA) alleles play an important role in immunity (cellular immunity) and may be important genetic traits. HLAAllele-specific interaction has not been well established. Recently, several studies had been conducted in order to do so, but the results are controversial and in some instances contradictory. Methods We designed a case-control study to quantify the association of HLA class I and II genes and breast cancer. HLA typing was performed by high resolution sequence-specific oligotyping after DNA amplification (PCR-SSOP) of 100 breast cancer Mexican mestizo patients and 99 matched healthy controls. Results HLA-A frequencies that we were able to observe that there was no difference between both groups from the statistical viewpoint. HLA-B*1501 was found three times more common in the case group (OR, 3.714; p = 0.031). HLA-Cw is not a marker neither for risk, nor protection for the disease, because we did not find significant statistical differences between the two groups. DRB1*1301, which is expressed in seven cases and in only one control, observing an risk increase of up to seven times and DRB1*1602, which behaves similarly in being present solely in the cases (OR, 16.701; 95% CI, 0.947 – 294.670). DQ*0301-allele expression, which is much more common in the control group and could be protective for the presentation of the disease (OR, 0.078; 95% CI, 0.027–0.223, p = 0.00001). Conclusion Our results reveal the role of the MHC genes in the pathophysiology of breast cancer, suggesting that in the development of breast cancer exists a disorder of immune regulation. The triggering factor seems to be restricted to certain ethnic groups and certain geographical regions since the relevant MHC alleles are highly diverse. This is the first study in Mexican

  10. Genetic Variants in IL6R and ADAM19 are Associated with COPD Severity in a Mexican Mestizo Population.

    PubMed

    Pérez-Rubio, Gloria; Silva-Zolezzi, Irma; Fernández-López, Juan Carlos; Camarena, Ángel; Velázquez-Uncal, Mónica; Morales-Mandujano, Fabiola; Hernández-Zenteno, Rafael De Jesús; Flores-Trujillo, Fernando; Sánchez-Romero, Candelaria; Velázquez-Montero, Alejandra; Espinosa de Los Monteros, Carlos; Sansores, Raúl H; Ramírez-Venegas, Alejandra; Falfán-Valencia, Ramcés

    2016-10-01

    Chronic obstructive pulmonary disease (COPD) is a complex and multifactorial disease with a strong genetic component. Our objective is to identify the genetic variants associated with COPD risk and its severity in Mexican Mestizo population. We evaluated 1285 single-nucleotide polymorphisms (SNPs) of candidate genes in 299 smokers with COPD (COPD-S) and 531 smokers without COPD (SWOC) using an Illumina GoldenGate genotyping microarray. In addition, 251 ancestry informative markers were included. Allele A of rs2545771 in CYP2F2P is associated with a lower risk of COPD (p = 4.02E-10, odds ratio [OR] = 0.104, confidence interval [CI] 95% 0.05-0.18). When the COPD group was stratified by severity according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD; levels III + IV vs. I + II), 3 SNPs (rs4329505 and rs4845626 in interleukin 6 receptor [IL6R] and rs1422794 in a disintegrin and metalloproteinase domain 19 [ADAM19]) were associated with a lower risk of suffering the most severe stages of the disease. rs2819096 in the surfactant protein D (SFTPD) gene was associated with a higher risk of COPD GOLD III + IV (p = 7.79E-03, OR = 1.80, CI 95% 1.16-2.79). Finally, the haplotype in IL6R was associated with a lower risk of suffering from more severe COPD, whereas the haplotype in ADAM19 was associated with a higher risk (p = 7.40E-03, OR = 2.83, CI 95% 1.20-6.86) of suffering from the severe stages of the disease. Our data suggest that there are alleles and haplotypes in the IL6R, ADAM19, and SFTPD genes associated with different severity stages of COPD; in CYP2F2P, rs25455771 is associated with a lower risk of COPD. PMID:27078193

  11. Analysis of Polymorphisms in Interleukin-10, Interleukin-6, and Interleukin-1 Receptor Antagonist in Mexican-Mestizo Women with Pre-eclampsia

    PubMed Central

    Valencia Villalvazo, Elith Yazmin; Canto-Cetina, Thelma; Romero Arauz, Juan Fernando; Coral-Vázquez, Ramón Mauricio; Canizales-Quinteros, Samuel; Coronel, Agustín; Carlos Falcón, Juan; Hernández Rivera, Jaime; Ibarra, Roberto; Polanco Reyes, Lucila

    2012-01-01

    Due to the fact that studies seeking associations of polymorphisms in regulatory regions of cytokine genes with pre-eclampsia (PE) have not always been consistent in different population analyses, the aim of this study was to investigate the possible association between rs1800896 of interleukin-10 (IL-10), rs1800795 of interleukin-6 (IL-6), and the variable number of tandem repeats (VNTR) in intron 2 of interleukin-1 receptor antagonist (IL-1Ra), as well as gene–gene interactions between these three polymorphisms with the presence of PE in Mexican-Mestizo women and one Amerindian population from México (Maya). A case–control study was performed where 411 pre-eclamptic cases and 613 controls were genotyped. For the rs1800896 of IL-10 and rs1800795 of IL-6, we used real-time polymerase chain reaction (PCR) allelic discrimination and for the VNTR of IL-1Ra, PCR. Allele frequency differences were assessed by Chi-squared test; logistic regression was used to test for associations; a gene–gene interaction was conducted. Genotypic and allelic distribution of the polymorphisms was similar in our population. The estimated of the gene–gene interaction between the polymorphisms did not differ significantly. However, we observed important differences in the distribution of the alleles and genotypes of the three polymorphisms analyzed between Mestiza-Mexicanas and Maya-Mestizo women. In conclusion, we did not find an association between polymorphisms in IL-10, IL-6, and IL-1Ra and PE in Mexican-Mestizo and Maya-Mestizo women. To our knowledge, this is the first time that these three polymorphisms were analyzed together with gene–gene interaction in women with PE. PMID:23013217

  12. Present-day deformation of the Pyrenees revealed by GPS surveying and earthquake focal mechanisms until 2011

    NASA Astrophysics Data System (ADS)

    Rigo, A.; Vernant, P.; Feigl, K. L.; Goula, X.; Khazaradze, G.; Talaya, J.; Morel, L.; Nicolas, J.; Baize, S.; Chéry, J.; Sylvander, M.

    2015-05-01

    The Pyrenean mountain range is a slowly deforming belt with continuous and moderate seismic activity. To quantify its deformation field, we present the velocity field estimated from a GPS survey of the Pyrenees spanning 18 yr. The PotSis and ResPyr networks, including a total of 85 GPS sites, were installed and first measured in 1992 and 1995-1997, respectively, and remeasured in 2008 and 2010. We obtain a deformation field with velocities less than 1 mm yr-1 across the range. The estimated velocities for individual stations do not differ significantly from zero with 95 per cent confidence. Even so, we estimate a maximum extensional horizontal strain rate of 2.0 ± 1.7 nanostrain per year in a N-S direction in the western part of the range. We do not interpret the vertical displacements due to their large uncertainties. In order to compare the horizontal strain rates with the seismic activity, we analyse a set of 194 focal mechanisms using three methods: (i) the `r' factor relating their P and T axes, (ii) the stress tensors obtained by fault slip inversion and (iii) the strain-rate tensors. Stress and strain-rate tensors are estimated for: (i) the whole data set, (ii) the eastern and western parts of the range separately, and (iii) eight zones, which are defined based on the seismicity and the tectonic patterns of the Pyrenees. Each of these analyses reveals a lateral variation of the deformation style from compression and extension in the east to extension and strike-slip in the west of the range. Although the horizontal components of the strain-rate tensors estimated from the seismic data are slightly smaller in magnitude than those computed from the GPS velocity field, they are consistent within the 2σ uncertainties. Furthermore, the orientations of their principal axes agree with the mapped active faults.

  13. Expression of NAT2 in immune system cells and the relation of NAT2 gene polymorphisms in the anti-tuberculosis therapy in Mexican mestizo population.

    PubMed

    Salazar-González, R; Gómez, R; Romano-Moreno, S; Medellín-Garibay, S; Núñez-Ruíz, A; Magaña-Aquino, M; Milán-Segovia, R C; Portales-Pérez, D P

    2014-12-01

    Arylamine N-acetyltransferase 2 (NAT2) metabolizes isoniazid (INH) and Single Nucleotide Polymorphisms (SNP) responsible for its activity has been reported. The aim of this study in the Mexican mestizo population was to evaluate NAT2 expression at the protein level in immune cells, as well as the distribution and frequency of six NAT2 SNPs and their association with anti-TB therapy, by measuring the plasma levels of INH and Acetyl-INH (AcINH). We performed genotyping assays of NAT2 SNPs in 40 TB patients and 121 healthy volunteers by real-time PCR. A method for detecting NAT2 in immune cells using flow cytometry was developed. Plasma concentrations of INH and AcINH were obtained by HPLC in TB patients and the Metabolic Ratio (MR) was calculated. The phenotypes obtained in the healthy volunteers were as follows; 18.87 % of subjects had the rapid acetylator phenotype, 45.45 % had the intermediate phenotype and 39.66 % exhibited the slow acetylator phenotype. In the TB patient group, 35 % of patients had the rapid acetylator phenotype, 32.5 % were intermediate and 32.5 % showed the slow acetylator phenotype. A higher expression level of NAT2 in innate immune cells from TB patients compared to those from healthy volunteers was detected (P < 0.013). In TB patients the MR showed a bimodal distribution with an antimode of 0.7, which was used as a threshold value for acetylator classification. A high correspondence between the rapid and slow acetylator phenotype with MR was demonstrated. In conclusion, the 282C>T, 341T>C, 481C>T, 590G>A, 803A>G, 857G>A SNPs of NAT2 gene provides accurate for prediction of the acetylator phenotype in Mexican mestizo population. A statistical difference was found in frequency of rapid metabolizer phenotype, which was higher in TB patients. In addition, the expression of NAT2 protein in immune cells can lead to further studies related to its functional role in the innate immune response against M. tuberculosis and other xenobiotics

  14. CYP2C9, CYP2C19, ABCB1 genetic polymorphisms and phenytoin plasma concentrations in Mexican-Mestizo patients with epilepsy.

    PubMed

    Ortega-Vázquez, A; Dorado, P; Fricke-Galindo, I; Jung-Cook, H; Monroy-Jaramillo, N; Martínez-Juárez, I E; Familiar-López, I; Peñas-Lledó, E; LLerena, A; López-López, M

    2016-06-01

    We aimed to explore the possible influence of CYP2C9 (*2, *3 and IVS8-109 A>T), CYP2C19 (*2, *3 and *17) and ABCB1 (1236C>T, 2677G>A/T and 3435C>T) on phenytoin (PHT) plasma concentrations in 64 Mexican Mestizo (MM) patients with epilepsy currently treated with PHT in mono- (n=25) and polytherapy (n=39). Genotype and allele frequencies of these variants were also estimated in 300 MM healthy volunteers. Linear regression models were used to assess associations between the dependent variables (PHT plasma concentration and dose-corrected PHT concentration) with independent variables (CYP2C9, CYP2C19 and ABCB1 genotypes, ABCB1 haplotypes, age, sex, weight, and polytherapy). In multivariate models, CYP2C9 IVS8-109 T was significantly associated with higher PHT plasma concentrations (t(64)=2.27; P=0.03). Moreover, this allele was more frequent in the supratherapeutic group as compared with the subtherapeutic group (0.13 versus 0.03, respectively; P=0.05, Fisher's exact test). Results suggest that CYP2C9 IVS8-109 T allele may decrease CYP2C9 enzymatic activity on PHT. More research is needed to confirm findings. PMID:26122019

  15. The 482Ser of PPARGC1A and 12Pro of PPARG2 Alleles Are Associated with Reduction of Metabolic Risk Factors Even Obesity in a Mexican-Mestizo Population

    PubMed Central

    Vázquez-Del Mercado, Mónica; Guzmán-Ornelas, Milton-Omar; Corona Meraz, Fernanda-Isadora; Ríos-Ibarra, Clara-Patricia; Reyes-Serratos, Eduardo-Alejandro; Castro-Albarran, Jorge; Ruíz-Quezada, Sandra-Luz; Navarro-Hernández, Rosa-Elena

    2015-01-01

    The aim of this study was to investigate the relationship between functional polymorphisms Gly482Ser in PPARGC1A and Pro12Ala in PPARG2 with the presence of obesity and metabolic risk factors. We included 375 individuals characterized as Mexican-Mestizos and classified by the body mass index (BMI). Body dimensions and distribution of body fat were measured. The HOMA-IR and adiposity indexes were calculated. Adipokines and metabolic profile quantification were performed by ELISA and routine methods. Genetic polymorphisms were determined by polymerase chain reaction restriction fragment length polymorphism analysis. A difference between obese and nonobese subjects in polymorphism PPARGC1A distribution was observed. Among obese individuals, carriers of genotype 482Gly/Gly were observed to have decreased body fat, BMI, and body fat ratio versus 482Ser/Ser carriers and increased resistin and leptin levels in carriers Gly+ phenotype versus Gly− phenotype. Subjects with PPARG2 Ala− phenotype (genotype 12Pro/Pro) showed a decreased HOMA-IR index versus individuals with Ala+ phenotype (genotypes 12Pro/Ala plus 12Ala/Ala). We propose that, in obese Mexican-Mestizos, the combination of alleles 482Ser in PPARGC1A and 12Pro in PPARG2 represents a reduced metabolic risk profile, even when the adiposity indexes are increased. PMID:26185753

  16. TGFBR2 mutation and MTHFR-C677T polymorphism in a Mexican mestizo population with cervico-cerebral artery dissection.

    PubMed

    Ruiz-Franco, Angélica; Barboza, Miguel A; Jara-Prado, Aurelio; Canizales-Quinteros, Samuel; Leon-Mimila, Paola; Arguelles-Morales, Nayelli; Vargas-González, Juan-Camilo; Quiroz-Compean, Alejandro; Arauz, Antonio

    2016-06-01

    Spontaneous cervico-cerebral artery dissection (CCAD) is a common condition found among young patients with ischemic stroke. We examined the possible association between the polymorphism of methylenetetrahydrofolate reductase (MTHFR)-C677T and the gene mutation in transforming growth factor beta receptor II (TGFBR2) in a cohort of CCAD patients. One-hundred CCAD cases (65 males; mean age: 38.08 ± 10.68 years) and 100 matching controls were included. Ancestry informative markers (AIMs) were used to increase internal validity of the genetic analysis. Genotypes of the C677T polymorphism in the MTHFR gene were determined by polymerase chain reaction and restriction fragment length polymorphism; direct sequencing was used for a mutation analysis of the TGFBR2 gene. Associations were evaluated using a multivariate statistics, and Hardy-Weinberg equilibrium was analyzed. We also incorporated our data into a meta-analysis of the MTHFR-C677T. Sixty-three patients presented with vertebral and 37 with carotid artery dissection. Ancestry markers found a call rate on each over 95 %. All AIMs did not deviate from Hardy-Weinberg equilibrium (p > 0.05). The homozygous TT genotype was more frequent in cases (OR 2.04, CI 95 % 1.53-2.72, p = 0.005), whereas no significant difference was found on heterozygous CT genotype. TGFBR2 mutation was not present in our samples. In the meta-analysis of MTHFR/C677T variant, a total 613 cases and 1547 controls were analyzed; we found a moderate association for the recessive model genotype (OR 2.04, CI 95 % 1.53-2.72; p = 0.342; Z = 4.83; I (2) = 11.3). This study supports a positive association between the MTHFR-C677T polymorphism and genetically confirmed Mexican mestizo CCAD patients. PMID:27017342

  17. The Italian present-day stress map

    NASA Astrophysics Data System (ADS)

    Montone, Paola; Mariucci, Maria Teresa; Pierdominici, Simona

    2012-05-01

    In this paper, we present a significant update of the Italian present-day stress data compilation not only to improve the knowledge on the tectonic setting of the region or to constrain future geodynamic models, but also to understand the mechanics of processes linked to faulting and earthquakes. In this paper, we have analysed, revised and collected new contemporary stress data from borehole breakouts and we have assembled earthquake and fault data. In total, 206 new quality-ranked entries complete the definition of the horizontal stress orientation and tectonic regime in some areas, and bring new information mainly in Sicily and along the Apenninic belt. Now the global Italian data set consists of 715 data points, including 499 of A-C quality, representing an increase of 37 per cent compared to the previous compilation. The alignment of horizontal stresses measured in some regions, closely matches the ˜N-S first-order stress field orientation of ongoing relative crustal motions between Eurasia and Africa plates. The Apenninic belt shows a diffuse extensional stress regime indicating a ˜NE-SW direction of extension, that we interpret as related to a second-order stress field. The horizontal stress rotations observed in peculiar areas reflect a complex interaction between first-order stress field and local effects revealing the importance of the tectonic structure orientations. In particular, in Sicily the new data delineate a more complete tectonic picture evidencing adjacent areas characterized by distinct stress regime: northern offshore of Sicily and in the Hyblean plateau the alignment of horizontal stresses is consistent with the crustal motions, whereas different directions have been observed along the belt and foredeep.

  18. The landscape of Neandertal ancestry in present-day humans

    PubMed Central

    Sankararaman, Sriram; Mallick, Swapan; Dannemann, Michael; Prüfer, Kay; Kelso, Janet; Pääbo, Svante; Patterson, Nick; Reich, David

    2014-01-01

    Analyses of Neandertal genomes have revealed that Neandertals have contributed genetic variants to modern humans1–2. The antiquity of Neandertal gene flow into modern humans means that regions that derive from Neandertals in any one human today are usually less than a hundred kilobases in size. However, Neandertal haplotypes are also distinctive enough that several studies have been able to detect Neandertal ancestry at specific loci1,3–8. Here, we have systematically inferred Neandertal haplotypes in the genomes of 1,004 present-day humans12. Regions that harbor a high frequency of Neandertal alleles in modern humans are enriched for genes affecting keratin filaments suggesting that Neandertal alleles may have helped modern humans adapt to non-African environments. Neandertal alleles also continue to shape human biology, as we identify multiple Neandertal-derived alleles that confer risk for disease. We also identify regions of millions of base pairs that are nearly devoid of Neandertal ancestry and enriched in genes, implying selection to remove genetic material derived from Neandertals. Neandertal ancestry is significantly reduced in genes specifically expressed in testis, and there is an approximately 5-fold reduction of Neandertal ancestry on chromosome X, which is known to harbor a disproportionate fraction of male hybrid sterility genes20–22. These results suggest that part of the reduction in Neandertal ancestry near genes is due to Neandertal alleles that reduced fertility in males when moved to a modern human genetic background. PMID:24476815

  19. Common Characteristics of Models in Present-Day Scientific Practice

    ERIC Educational Resources Information Center

    Van Der Valk, Ton; Van Driel, Jan H.; De Vos, Wobbe

    2007-01-01

    Teaching the use of models in scientific research requires a description, in general terms, of how scientists actually use models in their research activities. This paper aims to arrive at defining common characteristics of models that are used in present-day scientific research. Initially, a list of common features of models and modelling, based…

  20. The present-day number of tectonic plates

    NASA Astrophysics Data System (ADS)

    Harrison, Christopher G. A.

    2016-03-01

    The number of tectonic plates on Earth described in the literature has expanded greatly since the start of the plate tectonic era, when only about a dozen plates were considered in global models of present-day plate motions. With new techniques of more accurate earthquake epicenter locations, modern ways of measuring ocean bathymetry using swath mapping, and the use of space based geodetic techniques, there has been a huge growth in the number of plates thought to exist. The study by Bird (2003) proposed 52 plates, many of which were delineated on the basis of earthquake locations. Because of the pattern of areas of these plates, he suggested that there should be more small plates than he could identify. In this paper, I gather together publications that have proposed a total of 107 new plates, giving 159 plates in all. The largest plate (Pacific) is about 20 % of the Earth's area or 104 Mm2, and the smallest of which (Plate number 5 from Hammond et al. 2011) is only 273 km2 in area. Sorting the plates by size allows us to investigate how size varies as a function of order. There are several changes of slope in the plots of plate number organized by size against plate size order which are discussed. The sizes of the largest seven plates is constrained by the area of the Earth. A middle set of 73 plates down to an area of 97,563 km2 (the Danakil plate at number 80, is the plate of median size) follows a fairly regular pattern of plate size as a function of plate number. For smaller plates, there is a break in the slope of the plate size/plate number plot and the next 32 plates follow a pattern of plate size proposed by the models of Koehn et al. (2008) down to an area of 11,638 km2 (West Mojave plate # 112). Smaller plates do not follow any regular pattern of area as a function of plate number, probably because we have not sampled enough of these very small plates to reveal any clear pattern.

  1. Nuclear Fusion Drives Present-Day Accelerated Cosmic Expansion

    SciTech Connect

    Ying, Leong

    2010-09-30

    The widely accepted model of our cosmos is that it began from a Big Bang event some 13.7 billion years ago from a single point source. From a twin universe perspective, the standard stellar model of nuclear fusion can account for the Dark Energy needed to explain the mechanism for our present-day accelerated expansion. The same theories can also be used to account for the rapid inflationary expansion at the earliest time of creation, and predict the future cosmic expansion rate.

  2. Overcoming Present-Day Powerplant Limitations Via Unconventional Engine Configurations

    NASA Technical Reports Server (NTRS)

    Meitner, Peter L.

    2006-01-01

    The Army Research Laboratory s Vehicle Technology Directorate is sponsoring the prototype development of three unconventional engine concepts - two intermittent combustion (IC) engines and one turbine engine (via SBIR (Small Business Innovative Research) contracts). The IC concepts are the Nutating Engine and the Bonner Engine, and the turbine concept is the POWER Engine. Each of the three engines offers unique and greatly improved capabilities (which cannot be achieved by present-day powerplants), while offering significant reductions in size and weight. This paper presents brief descriptions of the physical characteristics of the three engines, and discusses their performance potentials, as well as their development status.

  3. Present-day dynamic and residual topography in central Anatolia

    NASA Astrophysics Data System (ADS)

    Uluocak, Ebru Şengül; Pysklywec, Russell; Göğüş, Oğuz H.

    2016-06-01

    The Central Anatolian orogenic plateau is represented by young volcanism, rapid plateau uplift, and distinctive (past and active) tectonic deformation. In this study, we consider observational data in terms of regional present-day geodynamics in the region. The residual topography of Central Anatolia was derived to define the regional isostatic conditions according to Airy isostasy and infer the potential role of "dynamic topography". Two-dimensional thermo-mechanical forward models for coupled mantle-lithosphere flow/deformation were conducted along a N-S directional profile through the region (e.g. northern/Pontides, interior, and southern/Taurides). These models were based on seismic tomography data that provide estimates about the present-day mantle thermal structure beneath the Anatolian plate. We compare the modelling results with calculated residual topography and independent data sets of geological deformation, gravity, and high surface heat flow/widespread geothermal activity. Model results suggest that there is ˜1 km of mantle flow induced dynamic topography associated with the sub-lithospheric flow driven by the seismically-inferred mantle structure. The uprising mantle may have also driven the asthenospheric source of volcanism in the north (e.g. Galatia volcanic province) and the Cappadocia volcanic province in the south while elevating the surface in the last 10 Myrs. Our dynamic topography calculations emphasize the role of vertical forcing under other orogenic plateaux underlain by relatively thin crust and low-density asthenospheric mantle.

  4. Present-day Antarctic Ice Mass Changes and Crustal Motion

    NASA Technical Reports Server (NTRS)

    James, Thomas S.; Ivins, Erik R.

    1995-01-01

    The peak vertical velocities predicted by three realistic, but contrasting, present-day scenarios of Antarctic ice sheet mass balance are found to be of the order of several mm/a. One scenario predicts local uplift rates in excess of 5 mm/a. These rates are small compared to the peak Antarctic vertical velocities of the ICE-3G glacial rebound model, which are in excess of 20 mm/a. If the Holocene Antarctic deglaciation history portrayed in ICE-3G is realistic, and if regional upper mantle viscosity is not an order of magnitude below 10(exp 21) pa s, then a vast geographical region in West Antarctica is uplifting at a rate that could be detected by a future Global Positioning System (GPS) campaign. While present-day scenarios predict small vertical crustal velocities, their overall continent-ocean mass exchange is large enough to account for a substantial portion of the observed secular polar motion ((Omega)m(bar)) and time-varying zonal gravity field J(sub 1).

  5. Present-day Antarctic ice mass changes and crustal motion

    NASA Technical Reports Server (NTRS)

    James, Thomas S.; Ivins, Erik R.

    1995-01-01

    The peak vertical velocities predicted by three realistic, but contrasting, present-day scenarios of Antarctic ice sheet mass balance are found to be of the order of several mm/a. One scenario predicts local uplift rates in excess of 5 mm/a. These rates are small compared to the peak Antarctic vertical velocities of the ICE-3G glacial rebound model, which are in excess of 20 mm/a. If the Holocene Antarctic deglaciation history protrayed in ICE-3G is realistic, and if regional upper mantle viscosity is not an order of magnitude below 10(exp 21) Pa(dot)s, then a vast geographical region in West Antarctica is uplifting at a rate that could be detected by a future Global Positioning System (GPS) campaign. While present-day scenarios predict small vertical crustal velocities, their overall continent-ocean mass exchange is large enough to account for a substantial portion of the observed secular polar motion (omega m(arrow dot)) and time-varying zonal gravity field.

  6. ADAPTION OF NONSTANDARD PIPING COMPONENTS INTO PRESENT DAY SEISMIC CODES

    SciTech Connect

    D. T. Clark; M. J. Russell; R. E. Spears; S. R. Jensen

    2009-07-01

    With spiraling energy demand and flat energy supply, there is a need to extend the life of older nuclear reactors. This sometimes requires that existing systems be evaluated to present day seismic codes. Older reactors built in the 1960s and early 1970s often used fabricated piping components that were code compliant during their initial construction time period, but are outside the standard parameters of present-day piping codes. There are several approaches available to the analyst in evaluating these non-standard components to modern codes. The simplest approach is to use the flexibility factors and stress indices for similar standard components with the assumption that the non-standard component’s flexibility factors and stress indices will be very similar. This approach can require significant engineering judgment. A more rational approach available in Section III of the ASME Boiler and Pressure Vessel Code, which is the subject of this paper, involves calculation of flexibility factors using finite element analysis of the non-standard component. Such analysis allows modeling of geometric and material nonlinearities. Flexibility factors based on these analyses are sensitive to the load magnitudes used in their calculation, load magnitudes that need to be consistent with those produced by the linear system analyses where the flexibility factors are applied. This can lead to iteration, since the magnitude of the loads produced by the linear system analysis depend on the magnitude of the flexibility factors. After the loading applied to the nonstandard component finite element model has been matched to loads produced by the associated linear system model, the component finite element model can then be used to evaluate the performance of the component under the loads with the nonlinear analysis provisions of the Code, should the load levels lead to calculated stresses in excess of Allowable stresses. This paper details the application of component-level finite

  7. On the Stability of Liquid Water on Present Day Mars

    NASA Technical Reports Server (NTRS)

    Haberle, Robert M.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    The mean annual surface pressure and temperature on present day Mars do not allow for the long term stability of liquid water on the surface. However, theoretical arguments have been advanced that suggest liquid water could form in transient events even though it would not be in equilibrium with the environment. Using a Mars General Circulation Model, we calculate where and for how long the surface pressure and surface temperature meet the minimum requirements for this metastability of liquid water. These requirements are that the pressure and temperature must be above the triple point of water, but below its boiling point. We find that there are five regions on Mars where these requirements are periodically satisfied: in the near equatorial regions of Amazonis, Arabia, and Elysium, and in the Hellas and Argyre impact basins. Whether liquid water ever forms in these regions depends on the availability of ice and heat, and on the evaporation rate. The latter is poorly understood for low pressure CO2 environments, but is likely to be so high that melting occurs rarely, if at all. However, in the relatively recent past, surface pressures may have been higher than they are today perhaps by as much as a factor of 2 or 3. Under these circumstances melting would have been easier to achieve. We plan to undertake laboratory experiments to better understand the potential for melting in low pressure environments.

  8. Phosphorus Necrosis of the Jaw: A Present-day Study

    PubMed Central

    Hughes, J. P. W.; Baron, R.; Buckland, D. H.; Cooke, M. A.; Craig, J. D.; Duffield, D. P.; Grosart, A. W.; Parkes, P. W. J.; Porter, A.

    1962-01-01

    A historical note on the aetiology of phossy jaw shows that present-day knowledge is little greater than it was a century ago. The varied clinical course of the disease is described together with a report of 10 classical cases not previously reported. Six cases, not amounting to true necrosis but in which healing after dental extraction was delayed, and described, and mention is made of the noticeable differences in the oral state and appearances of tartar of healthy workmen exposed to phosphorus compared with healthy workmen not exposed. But no systematic differences of any kind were found in the incidence of general infections, fractures of bones, haematological findings, and biochemical studies of blood and urine in two groups of healthy men most exposed and least exposed to phosphorous in the same factory. An intensive study in hospital of a case of classical necrosis showed no departure from normal, except delayed healing following bone biopsy from the iliac crest, and a reversed polymorphonuclear/lymphocyte ratio. In the discussion the time of onset of necrosis after first exposure to phosphorus, clinical and radiological diagnosis, the organisms present, personal susceptibility, the appearance of the sequestra, and regeneration of bone are considered. An up-to-date note on prevention of the disease is given, although this has met with only partial success. Some persons are highly susceptible and, whilst complete protection is impossible in the light of our present knowledge, early diagnosis and modern treatment have robbed the disease of its terrible manifestations of Victorian times and turned it into a minor, although often uncomfortable complaint, with little or no resulting disability. Images PMID:14449812

  9. Present Day Activity of South Polar Gullies on Mars

    NASA Astrophysics Data System (ADS)

    Raack, J.; Reiss, D.; Ruesch, O.; Hiesinger, H.

    2012-04-01

    Here we report on clearly identified seasonal changes of gullies observed within the last two martian years (MY) on slopes of a south polar pit, which is located in a filled crater (diameter ~54 km) north of Sisyphi Cavi at ~68.5°S and ~1.5°E. Using new high-resolution imaging (High Resolution Imaging Science Experiment, HiRISE), temperature (Thermal Emission Spectrometer, TES) and spectral data (Compact Reconnaissance Imaging Spectrometer for Mars, CRISM; Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité, OMEGA), we analyzed the exact timing of changes of gullies and detect the possible medium (CO2, H2O or dry) and mechanism which initiate present day gully activity. Two locations in the study region with clear modifications of gullies were identified in MY 29 between LS 226° and LS 247° and between LS 209° and LS 247°. In MY 30 changes occur in both locations between LS 218° and LS 249°. Modifications are the formation of a new small apron and new deposits within the channel, both associated with the deposition of dark material. Erosion in gully alcoves or channels was not observed. TES data show temperatures between ~180 and ~240 K within the period of gully modifications. Maximum temperatures in the region rise up to ~285 K between LS ~270° and ~310°. Spectral data show a CO2-cover of the study region until LS 227°. CO2-ice free surface are spectrally observed for the first time at LS 249°. H2O was not spectrally detected in the study region and a mixture of CO2 and H2O as presented in [1] cannot be clearly detected. Unfortunately, there are no spectral data available between LS 227° and 249°. Modifications of gullies imply seasonal volatile activity. The activity can be narrowed down to occur between LS 226° and 247° at mean temperatures between ~180 and ~240 K. This is in the range of temperatures where CO2 sublimates back into the atmosphere. Based on the temperature range, the most likely candidate for the observed new

  10. Modelling economic losses of historic and present-day high-impact winter windstorms in Switzerland

    DOE PAGESBeta

    Welker, Christoph; Martius, Olivia; Stucki, Peter; Bresch, David; Dierer, Silke; Bronnimann, Stefan

    2016-03-30

    This study investigates the wind gusts and associated economic loss patterns of high-impact winter windstorms in Switzerland between 1871 and 2011. A novel approach for simulating windstorm-related gusts and losses at regional to local scales is applied to a sample of 84 windstorms. The approach involves the dynamical downscaling of the Twentieth Century Reanalysis (20CR) ensemble mean to 3-km horizontal grid size using the Weather Research and Forecasting (WRF) model. Economic losses are simulated at municipal level for present-day asset distribution based on the downscaled (parameterised) wind gusts at high spatiotemporal resolution using the open-source impact model climada. A comparisonmore » with insurance loss data for two recent windstorms ("Lothar'' in 1999, "Joachim'' in 2011) indicates that the loss simulation allows to realistically simulate the spatial patterns of windstorm losses. The loss amplitude is strongly underestimated for 'Lothar', while it is in reasonable agreement for 'Joachim'. Possible reasons are discussed. Uncertainties concerning the loss simulation arise from the wind gust estimation method applied; estimates can differ considerably among the different methods, in particular over high orography. Furthermore, the quality of the loss simulation is affected by the underlying simplified assumptions regarding the distribution of assets and their susceptibilities to damage. For the whole windstorm sample, composite averages of simulated wind gust speed and loss are computed. Both composites reveal high values for the densely populated Swiss Plateau and lower values for south-eastern Switzerland; metropolitan areas stand out in the loss composite. Eight of the top 10 events concerning the losses simulated for present-day asset distribution and summed over all Swiss municipalities occurred after 1950. Furthermore, it remains uncertain whether this is due to decadal-scale changes of winter windstorms in Switzerland or merely due to a possible

  11. The evolution of galaxies from primeval irregulars to present-day ellipticals.

    PubMed

    Mori, Masao; Umemura, Masayuki

    2006-03-30

    Galaxy formation is believed to proceed in a 'bottom up' manner, starting with the formation of small clumps of gas and stars that then merge hierarchically into giant systems. The baryonic gas loses thermal energy by radiative cooling and falls towards the centres of the new galaxies, while supernovae blow gas out. Any realistic model therefore requires a proper treatment of these processes, but hitherto this has been far from satisfactory. Here we report a simulation that follows evolution from the earliest stages of galaxy formation through the period of dynamical relaxation, at which point the resulting galaxy is in its final form. The bubble structures of gas revealed in our simulation (for times of less than 3 x 10(8) years) resemble closely high-redshift Lyman-alpha emitters. After 10(9) years, these bodies are dominated by stellar continuum radiation and then resemble the Lyman break galaxies, which are high-redshift star-forming galaxies. At this point, the abundance of elements heavier than helium ('metallicity') appears to be solar. After 1.3 x 10(10) years, these galaxies resemble present-day ellipticals. PMID:16572164

  12. Diversity and biogeography of present-day magnetotactic bacteria in eastern China

    NASA Astrophysics Data System (ADS)

    Lin, W.; Wang, Y.; Pan, Y.

    2012-12-01

    A number of microorganisms are able to biomineralize iron minerals. Among them, magnetotactic bacteria (MTB) mineralize intracellular membrane-enveloped magnetite and/or greigite, known as magnetosomes that help cells to swim along the Earth's magnetic field. In recent years, MTB have become an attractive model system for investigating the biogeomagnetism. The occurrence of MTB has been reported in aquatic environments from freshwater to marine ecosystems. And, fossil magnetosomes are found to be potential carriers of natural remanent magnetization and indicators of paleoenvironmental changes. However, their distribution across heterogeneous habitats remains unclear. Here we report the diversity and biogeography of MTB from more than 20 locations from freshwater to saline habitats in eastern China. Great morphological variability was observed in MTB communities through light and transmission electron microscope observation. Phylogenetic analysis based on 16S rRNA genes has revealed that identified MTB belonged to the Alphaproteobacteria, Deltaproteobacteria, Gammaproteobacteria, and the phylum Nitrospirae. The overall composition of MTB communities was compared, and we found a restricted distribution of MTB communities across a large spatial scale with pronounced endemicity. Variation partitioning analyses indicated that the biogeography of MTB is relatively more influenced by environmental factors (e.g., salinity, sulfate, total iron, Eh, and temperature) than geographic distance. More interestingly, we found, for the first time, that the strength of the Earth's magnetic field appears to influence the biogeography of MTB, implying an impact of geophysical effects on these microorganisms. Our results infer that MTB community represents a biogeographic distribution across the studied heterogeneous environments. Knowledge of the present-day MTB biogeography may be applied towards the reconstruction of paleo-environments and assessment of contribution of bacterial

  13. Present-day secular variations in the zonal harmonics of earth's geopotential

    NASA Technical Reports Server (NTRS)

    Mitrovica, J. X.; Peltier, W. R.

    1993-01-01

    The mathematical formulation required for predicting secular variation in the geopotential is developed for the case of a spherically symmetric, self-gravitating, viscoelastic earth model and an arbitrary surface load which can include a gravitational self-consistent ocean loading component. The theory is specifically applied to predict the present-day secular variation in the zonal harmonics of the geopotenial arising from the surface mass loading associated with the late Pleistocene glacial cycles. A procedure is outlined in which predictions of the present-day geopotential signal due to the late Pleistocene glacial cycles may be used to derive bounds on the net present-day mass flux from the Antarctic and Greenland ice sheets to the local oceans.

  14. Present-day Mars' water cycle: new views and blind perspectives

    NASA Astrophysics Data System (ADS)

    Montmessin, F.; Smith, M. D.; Fedorova, A.; Langevin, Y.; Mellon, M.

    2012-09-01

    Addressing recent cimate changes on Mars necessarily requires a succesful representation of present-day Mars water cycle. Decades of observations and modeling efforts have been conducted that now allow to elaborate a new, yet incomplete, picture, of the seasonal activity of water on Mars. This presentation explores the various observational and theoretical studies that have been conducted to date, and attempts to present a clear and detailed explanation of the major physical mechanisms that command the seasonal and geographical variability of present-day Mars water cycle, as inferred from the combined analysis of measurements and climate model simulations. Remaining issues and enigmae will be presented as well.

  15. Historical trauma as public narrative: A conceptual review of how history impacts present-day health

    PubMed Central

    Mohatt, Nathaniel Vincent; Thompson, Azure B.; Thai, Nghi D.; Tebes, Jacob Kraemer

    2014-01-01

    Theories of historical trauma increasingly appear in the literature on individual and community health, especially in relation to racial and ethnic minority populations and groups that experience significant health disparities. As a consequence of this rapid growth, the literature on historical trauma comprises disparate terminology and research approaches. This critical review integrates this literature in order to specify theoretical mechanisms that explain how historical trauma influences the health of individuals and communities. We argue that historical trauma functions as a public narrative for particular groups or communities that connects present-day experiences and circumstances to the trauma so as to influence health. Treating historical trauma as a public narrative shifts the research discourse away from an exclusive search for past causal variables that influence health to identifying how present-day experiences, their corresponding narratives, and their health impacts are connected to public narratives of historical trauma for a particular group or community. We discuss how the connection between historical trauma and present-day experiences, related narratives, and health impacts may function as a source of present-day distress as well as resilience. PMID:24561774

  16. Present-day Stress Pattern of Turkey from Inversion of Updated Earthquake Focal Mechanism Catalogue

    NASA Astrophysics Data System (ADS)

    Özacar, A.

    2011-12-01

    Active tectonic setting of Turkey is characterized by different stress regimes. In order to analyze present-day tectonic stresses throughout the country, all available earthquake focal mechanisms with updated locations reported by the International Seismological Center (ISC) and national catalogues are compiled between 34° - 43° latitudes and 25° - 46° longitudes. Focal mechanisms of earthquakes with multiple solutions are chosen based on their reliability and consistency with the local tectonic setting. The resultant database which includes 1391 events occurred during the period 1909 - 2010 with magnitudes ranging from 2.0 to 8.0 and depths reaching up to 165 km, constitutes the base information for better active fault characterization in seismic hazard analyses. Using this catalogue, the pressure-tension axes, maximum-minimum horizontal stress axes, and tectonic stress regime of each earthquake are determined following the World Stress Map (WSM) project guidelines and analyzed separately for crustal and intermediate depth earthquakes. During stress inversion, crustal events are grouped in 36 and intermediate depth events in 2 distinct regions on the basis of their geographical proximity, kinematic homogeneity and tectonic setting to minimize the amount of heterogeneity and map the variations in the stress field. In the following stage, results of independent stress inversions including orientations of the three principal compressive stresses (σ1 = maximum, σ2 = intermediate, and σ3 = minimum), ratio of stress magnitudes (σ2 - σ3 / σ1 - σ3), and dominant stress regimes, are analyzed along with seismicity recorded by national seismic networks and previously mapped active faults. Our results reveal widespread strike-slip faulting in the crust throughout Turkey including North Anatolian Fault Zone, North Aegean Trough, Pliny-Strabo Trenches, Paphos Transform Fault, Tuzgölü Fault, East Anatolian Fault Zone, and East Anatolian Plateau. The regions

  17. Present-day kinematics of the Rivera plate and implications for tectonics in southwestern Mexico

    NASA Technical Reports Server (NTRS)

    Demets, Charles; Stein, Seth

    1990-01-01

    A model for the present-day motion of the Rivera plate relative to the North America, Cocos, and Pacific plates is derived using new data from the Pacific-Rivera rise and Rivera transform fault, together with new estimates of Pacific-Rivera motions. The results are combined with the closure-consistent NUVEL-1 global plate motion model of DeMets et al. (1990) to examine present-day deformation in southwestern Mexico. The analysis addresses several questions raised in previous studies of the Rivera plate. Namely, do plate motion data from the northern East Pacific rise require a distinct Rivera plate? Do plate kinematic data require the subduction of the Rivera plate along the seismically quiescent Acapulco trench? If so, what does the predicted subduction rate imply about the earthquake recurrence interval in the Jalisco region of southwestern Mexico?

  18. Mantle rheology and satellite signatures from present-day glacial forcings

    NASA Technical Reports Server (NTRS)

    Sabadini, Roberto; Yuen, David A.; Gasperini, Paolo

    1988-01-01

    Changes in the long-wavelength region of the earth's gravity field resulting from both present-day glacial discharges and the possible growth of the Antarctic ice sheet are considered. Significant differences in the responses between the Maxell and Burger body rheologies are found for time spans of less than 100 years. The quantitative model for predicting the secular variations of the gravitational potential, and means for incorporating glacial forcings, are described. Results are given for the excitation of the degree two harmonics. It is suggested that detailed satellite monitoring of present-day ice movements in conjunction with geodetic satellite missions may provide a reasonable alternative for the esimation of deep mantle viscosity.

  19. Present-day kinematics of the Rivera plate and implications for tectonics in southwestern Mexico

    NASA Astrophysics Data System (ADS)

    Demets, Charles; Stein, Seth

    1990-12-01

    A model for the present-day motion of the Rivera plate relative to the North America, Cocos, and Pacific plates is derived using new data from the Pacific-Rivera rise and Rivera transform fault, together with new estimates of Pacific-Rivera motions. The results are combined with the closure-consistent NUVEL-1 global plate motion model of DeMets et al. (1990) to examine present-day deformation in southwestern Mexico. The analysis addresses several questions raised in previous studies of the Rivera plate. Namely, do plate motion data from the northern East Pacific rise require a distinct Rivera plate? Do plate kinematic data require the subduction of the Rivera plate along the seismically quiescent Acapulco trench? If so, what does the predicted subduction rate imply about the earthquake recurrence interval in the Jalisco region of southwestern Mexico?

  20. Convergence, divergence, and parallelism in marine biodiversity trends: Integrating present-day and fossil data

    NASA Astrophysics Data System (ADS)

    Huang, Shan; Roy, Kaustuv; Valentine, James W.; Jablonski, David

    2015-04-01

    Paleontological data provide essential insights into the processes shaping the spatial distribution of present-day biodiversity. Here, we combine biogeographic data with the fossil record to investigate the roles of parallelism (similar diversities reached via changes from similar starting points), convergence (similar diversities reached from different starting points), and divergence in shaping the present-day latitudinal diversity gradients of marine bivalves along the two North American coasts. Although both faunas show the expected overall poleward decline in species richness, the trends differ between the coasts, and the discrepancies are not explained simply by present-day temperature differences. Instead, the fossil record indicates that both coasts have declined in overall diversity over the past 3 My, but the western Atlantic fauna suffered more severe Pliocene-Pleistocene extinction than did the eastern Pacific. Tropical western Atlantic diversity remains lower than the eastern Pacific, but warm temperate western Atlantic diversity recovered to exceed that of the temperate eastern Pacific, either through immigration or in situ origination. At the clade level, bivalve families shared by the two coasts followed a variety of paths toward today's diversities. The drivers of these lineage-level differences remain unclear, but species with broad geographic ranges during the Pliocene were more likely than geographically restricted species to persist in the temperate zone, suggesting that past differences in geographic range sizes among clades may underlie between-coast contrasts. More detailed comparative work on regional extinction intensities and selectivities, and subsequent recoveries (by in situ speciation or immigration), is needed to better understand present-day diversity patterns and model future changes.

  1. Convergence, divergence, and parallelism in marine biodiversity trends: Integrating present-day and fossil data.

    PubMed

    Huang, Shan; Roy, Kaustuv; Valentine, James W; Jablonski, David

    2015-04-21

    Paleontological data provide essential insights into the processes shaping the spatial distribution of present-day biodiversity. Here, we combine biogeographic data with the fossil record to investigate the roles of parallelism (similar diversities reached via changes from similar starting points), convergence (similar diversities reached from different starting points), and divergence in shaping the present-day latitudinal diversity gradients of marine bivalves along the two North American coasts. Although both faunas show the expected overall poleward decline in species richness, the trends differ between the coasts, and the discrepancies are not explained simply by present-day temperature differences. Instead, the fossil record indicates that both coasts have declined in overall diversity over the past 3 My, but the western Atlantic fauna suffered more severe Pliocene-Pleistocene extinction than did the eastern Pacific. Tropical western Atlantic diversity remains lower than the eastern Pacific, but warm temperate western Atlantic diversity recovered to exceed that of the temperate eastern Pacific, either through immigration or in situ origination. At the clade level, bivalve families shared by the two coasts followed a variety of paths toward today's diversities. The drivers of these lineage-level differences remain unclear, but species with broad geographic ranges during the Pliocene were more likely than geographically restricted species to persist in the temperate zone, suggesting that past differences in geographic range sizes among clades may underlie between-coast contrasts. More detailed comparative work on regional extinction intensities and selectivities, and subsequent recoveries (by in situ speciation or immigration), is needed to better understand present-day diversity patterns and model future changes. PMID:25901312

  2. Convergence, divergence, and parallelism in marine biodiversity trends: Integrating present-day and fossil data

    PubMed Central

    Huang, Shan; Roy, Kaustuv; Valentine, James W.; Jablonski, David

    2015-01-01

    Paleontological data provide essential insights into the processes shaping the spatial distribution of present-day biodiversity. Here, we combine biogeographic data with the fossil record to investigate the roles of parallelism (similar diversities reached via changes from similar starting points), convergence (similar diversities reached from different starting points), and divergence in shaping the present-day latitudinal diversity gradients of marine bivalves along the two North American coasts. Although both faunas show the expected overall poleward decline in species richness, the trends differ between the coasts, and the discrepancies are not explained simply by present-day temperature differences. Instead, the fossil record indicates that both coasts have declined in overall diversity over the past 3 My, but the western Atlantic fauna suffered more severe Pliocene−Pleistocene extinction than did the eastern Pacific. Tropical western Atlantic diversity remains lower than the eastern Pacific, but warm temperate western Atlantic diversity recovered to exceed that of the temperate eastern Pacific, either through immigration or in situ origination. At the clade level, bivalve families shared by the two coasts followed a variety of paths toward today’s diversities. The drivers of these lineage-level differences remain unclear, but species with broad geographic ranges during the Pliocene were more likely than geographically restricted species to persist in the temperate zone, suggesting that past differences in geographic range sizes among clades may underlie between-coast contrasts. More detailed comparative work on regional extinction intensities and selectivities, and subsequent recoveries (by in situ speciation or immigration), is needed to better understand present-day diversity patterns and model future changes. PMID:25901312

  3. Multimodel intercomparison of preindustrial, present-day and future tropospheric OH and methane lifetime

    NASA Astrophysics Data System (ADS)

    Voulgarakis, A.; Naik, V.; Archibald, A. T.; Collins, B.; Dentener, F. J.; Josse, B.; Lamarque, J.; Prather, M. J.; Shindell, D. T.; Stevenson, D. S.; Sudo, K.; Szopa, S.; Takemura, T.; Wild, O.; Williams, J.; Young, P. J.; Zeng, G.

    2011-12-01

    The oxidizing capacity of the atmosphere heavily depends on the levels of the hydroxyl radical (OH) and its geographical distribution. OH removes a wide range of pollutants and non-CO2 greenhouse gases from the atmosphere. It controls the atmospheric lifetime of methane, the most important anthropogenic greenhouse gas after carbon dioxide, and is key to the formation of tropospheric ozone and aerosols. Because of its crucial role, it is important to understand how OH has changed from preindustrial to present day, and how it may change in the future in response to different emission scenarios. Here, we analyze simulations performed for the Atmospheric Chemistry and Climate Modeling Intercomparison Project (ACCMIP), in support of the IPCC AR5, to investigate the changes in global and regional OH and consequent changes in methane lifetime between 1850 and 2100. The ACCMIP project includes a variety of chemistry-climate models, which were run for the historical period (1850 to present-day) and for the future (present-day to 2100) following the different Representative Concentration Pathways (RCPs). A wide range of chemical output from these simulations is expected to contribute to our understanding of chemistry-climate interactions. We identify changes in OH and methane lifetime, and also the key drivers of these changes, including the ratio between different emissions (NOx, CO, VOCs), changes in water vapor, as well as changes in the ozone photolysis rate and factors affecting it (stratospheric ozone, aerosols and clouds).

  4. Minimal effects of latitude on present-day speciation rates in New World birds.

    PubMed

    Rabosky, Daniel L; Title, Pascal O; Huang, Huateng

    2015-06-22

    The tropics contain far greater numbers of species than temperate regions, suggesting that rates of species formation might differ systematically between tropical and non-tropical areas. We tested this hypothesis by reconstructing the history of speciation in New World (NW) land birds using BAMM, a Bayesian framework for modelling complex evolutionary dynamics on phylogenetic trees. We estimated marginal distributions of present-day speciation rates for each of 2571 species of birds. The present-day rate of speciation varies approximately 30-fold across NW birds, but there is no difference in the rate distributions for tropical and temperate taxa. Using macroevolutionary cohort analysis, we demonstrate that clades with high tropical membership do not produce species more rapidly than temperate clades. For nearly any value of present-day speciation rate, there are far more species in the tropics than the temperate zone. Any effects of latitude on speciation rate are marginal in comparison to the dramatic variation in rates among clades. PMID:26019156

  5. Simulating present-day and future air quality as climate changes: Model evaluation

    NASA Astrophysics Data System (ADS)

    Dawson, John P.; Racherla, Pavan N.; Lynn, Barry H.; Adams, Peter J.; Pandis, Spyros N.

    The global-regional climate-air pollution modeling system (GRE-CAPS) has been developed, coupling an existing general circulation model/chemical transport model (GCM/CTM), a regional meteorological model, and a regional chemical transport model. This system is intended to enable studies of the effects of changes in climate, intercontinental transport, and emissions on regional and urban air quality. The GRE-CAPS system consists of the GISS II' GCM/CTM, the MM5 regional meteorological model, and the PMCAMx regional CTM. The modeling system is evaluated for the present day, with comparisons between model-predicted, measured ozone, and speciated PM 2.5 concentrations. The ability of the model to predict present-day concentrations of ozone and PM 2.5 is compared to that of PMCAMx when used for retrospective modeling. Comparisons between model-predicted temperatures and precipitation are also made. The model was used to simulate five present-day Januaries and six present-day Julys. The biases and errors in GRE-CAPS-predicted ozone concentrations were similar to those of PMCAMx when used for standard retrospective modeling. The fractional biases in mean daily peak ozone concentration and mean daily maximum 8-h average ozone concentration are both <10%. The model-predicted distribution of peak hourly and daily maximum 8-h average values agreed rather well with the measured distribution. There is less agreement between the model and measurements in the number of hours with ozone mixing ratios >70 or 80 ppb, though this is also the case with standard PMCAMx modeling. The predictions of PM 2.5 concentrations by GRE-CAPS were also of similar quality to those of PMCAMx driven by historical meteorology. The fractional biases in the predictions of total PM 2.5, sulfate, ammonium, and nitrate were all <25% in both January and July. The model agrees well with organic PM 2.5 measurements from the IMPROVE network, though there is less agreement with measurements from the STN network

  6. Association of vWA and TPOX Polymorphisms with Venous Thrombosis in Mexican Mestizos

    PubMed Central

    Meraz-Ríos, Marco Antonio; Majluf-Cruz, Abraham; Santana, Carla; Noris, Gino; Camacho-Mejorado, Rafael; Acosta-Saavedra, Leonor C.; Calderón-Aranda, Emma S.; Hernández-Juárez, Jesús; Magaña, Jonathan J.; Gómez, Rocío

    2014-01-01

    Objective. Venous thromboembolism (VTE) is a multifactorial disorder and, worldwide, the most important cause of morbidity and mortality. Genetic factors play a critical role in its aetiology. Microsatellites are the most important source of human genetic variation having more phenotypic effect than many single nucleotide polymorphisms. Hence, we evaluate a possible relationship between VTE and the genetic variants in von Willebrand factor, human alpha fibrinogen, and human thyroid peroxidase microsatellites to identify possible diagnostic markers. Methods. Genotypes were obtained from 177 patients with VTE and 531 nonrelated individuals using validated genotyping methods. The allelic frequencies were compared; Bayesian methods were used to correct population stratification to avoid spurious associations. Results. The vWA-18, TPOX-9, and TPOX-12 alleles were significantly associated with VTE. Moreover, subjects bearing the combination vWA-18/TPOX-12 loci exhibited doubled risk for VTE (95% CI = 1.02–3.64), whereas the combination vWA-18/TPOX-9 showed an OR = 10 (95% CI = 4.93–21.49). Conclusions. The vWA and TPOX microsatellites are good candidate biomarkers in venous thromboembolism diseases and could help to elucidate their origins. Additionally, these polymorphisms could become useful markers for genetic studies of VTE in the Mexican population; however, further studies should be done owing that this data only show preliminary evidence. PMID:25250329

  7. Utilizing Present-Day Stable Water Isotopes to Improve Paleoclimate Records from the Southeast (USA)

    NASA Astrophysics Data System (ADS)

    McKay, K. K.; Lambert, W. J.

    2015-12-01

    Present-day water isotope data are used to help interpret climate (paleo-rainfall) proxies archived in the geologic record, which can then aid in the creation of General Circulation Models (GCM). The Southeast (USA) is under-represented with respect to present-day measurement of water isotopes and high-resolution paleoclimate records, thus GCMs must extrapolate data for the region. We will evaluate water isotope data (δ18O, δD) collected and analyzed at The University of Alabama (33°13'N, 87°33'W) since June 2005. The monitoring station, central to the Southeast, was established to provide long-term water isotope data needed for reconstructing paleo-rainfall records of the region. Proxy data (e.g., δ18Ocalcite) archived in speleothems have been demonstrated to provide trustworthy information about past climate conditions; however, present-day monitoring of both local rainfall and cave dripwater are crucial. The decade-long (June 2005 - May 2015) rainfall record allows for the establishment of the relationship between water isotopes (δ18O, δD) and monthly air temperature, rainfall amount, as well as the general differences between summer and winter rainfall. Dripwater from Cathedral Caverns (34°34'N, 86°13'W), located in northeastern Alabama, has been sampled at a monthly resolution since January 2015 to determine if the water chemistry in the cave represents an annual mean for the rainfall or if it is seasonally biased. The ultimate goal of this study is to better understand how atmospheric air currents (specifically the strength/position of the Polar Jet Stream, PJS), and hence rainfall in the Southeast, varied during past periods of relative warming (e.g., Dansgaard-Oeschger events) and cooling (e.g., Heinrich events) of the Northern Hemisphere atmosphere. Future GCMs will be improved if a reliable high-resolution paleo-rainfall record can be produced for the Southeast.

  8. Evaluation of a wetland methane emission parameterization for present-day and Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Basu, A.; Schultz, M. G.; Francois, L.

    2012-04-01

    Wetlands are the largest natural source of atmospheric methane and presumably contribute ~25-40% to its annual budget (~500 Tg). However, there remain considerable uncertainties in estimation of global wetlands and their methane emissivity, given the large domain of their vegetation and hydrological characteristics. In this study, we describe the development of a wetland methane emission model in conjunction with global wetland parameterization at seasonal resolution. Contrary to most of the other modeling studies, our model is based on a simple parameterization and also readily adaptable to different paleo climatic scenarios, in which the role of methane is still largely unexplored. Wetlands with a strong climatic sensitivity are perceived to be a key factor in past changes of atmospheric methane concentration, e.g. the double fold increase since the Last Glacial Maximum (LGM). The present parameterization is primarily based on CARAIB, a large scale dynamic vegetation model designed to study the role of vegetation in the global carbon cycle. Its hydrological module is adept at simulating soil water and several associated hydrological fluxes over various biome types. Our model parameterization uses three basic drivers from CARAIB: soil water, soil temperature and soil carbon content along with high resolution terrain slope data. The emission model is included in the chemistry climate model ECHAM5-MOZ for present day and also used in LGM methane simulations. The model results are evaluated in comparison with atmospheric methane observations from the NOAA-CMDL flask network and ice core records for LGM. We obtained the present day wetland methane source to be 153 Tg/year, which lies near the lower edge of model assumptions. We also discuss the uncertainties of the present day simulation and the impact of emission scaling on atmospheric concentration. The latitudinal distribution of other major methane sources, uncertainties in their budget and their potential role in

  9. Present-day Exposures of Water Ice in the Northern Mid-latitudes of Mars

    NASA Technical Reports Server (NTRS)

    Allen, Carlton C.; Kanner, Lisa C.

    2007-01-01

    Water ice is exposed in the martian north polar cap, but is rarely exposed beyond the cap boundary. Orbital gamma ray spectrometry data strongly imply the presence of water ice within meters of the surface at latitudes north of approximately 60deg. We have examined mid-latitude areas of the northern plains displaying residual ice-rich layers, and report evidence of present-day surface exposures of water ice. These exposures, if confirmed, could con-strain the latitudinal and temporal stability of surface ice on Mars.

  10. Functional Analyses of Transcription Factor Binding Sites that Differ between Present-Day and Archaic Humans.

    PubMed

    Weyer, Sven; Pääbo, Svante

    2016-02-01

    We analyze 25 previously identified transcription factor binding sites that carry DNA sequence changes that are present in all or nearly all present-day humans, yet occur in the ancestral state in Neandertals and Denisovans, the closest evolutionary relatives of humans. When the ancestral and derived forms of the transcription factor binding sites are tested using reporter constructs in 3 neuronal cell lines, the activity of 12 of the derived versions of transcription factor binding sites differ from the respective ancestral variants. This suggests that the majority of this class of evolutionary differences between modern humans and Neandertals may affect gene expression in at least some tissue or cell type. PMID:26454764

  11. Functional Analyses of Transcription Factor Binding Sites that Differ between Present-Day and Archaic Humans

    PubMed Central

    Weyer, Sven; Pääbo, Svante

    2016-01-01

    We analyze 25 previously identified transcription factor binding sites that carry DNA sequence changes that are present in all or nearly all present-day humans, yet occur in the ancestral state in Neandertals and Denisovans, the closest evolutionary relatives of humans. When the ancestral and derived forms of the transcription factor binding sites are tested using reporter constructs in 3 neuronal cell lines, the activity of 12 of the derived versions of transcription factor binding sites differ from the respective ancestral variants. This suggests that the majority of this class of evolutionary differences between modern humans and Neandertals may affect gene expression in at least some tissue or cell type. PMID:26454764

  12. EXPECTED NUMBER OF MASSIVE GALAXY RELICS IN THE PRESENT DAY UNIVERSE

    SciTech Connect

    Quilis, Vicent; Trujillo, Ignacio

    2013-08-10

    The number of present day massive galaxies that have survived untouched since their formation at high-z is an important observational constraint to the hierarchical galaxy formation models. Using three different semianalytical models based on the Millenium simulation, we quantify the expected fraction and number densities of the massive galaxies that form at z > 2 and have evolved in stellar mass less than 10% and 30%. We find that only a small fraction of the massive galaxies that already formed at z {approx} 2 have remained almost unaltered since their formation (<2% with {Delta}M{sub *}/M{sub *} < 0.1 and <8% with {Delta}M{sub *}/M{sub *} < 0.3). These fractions correspond to the following number densities of massive relics in the present day universe: {approx}1.2 Multiplication-Sign 10{sup -6} Mpc{sup -3} for {Delta}M{sub *}/M{sub *} < 0.1 and {approx}5.7 Multiplication-Sign 10{sup -6} Mpc{sup -3} for {Delta}M{sub *}/M{sub *} < 0.3. The observed number of relic candidates found in the nearby universe is rather uncertain today (with uncertainties up to a factor of {approx}100), preventing us from establishing firm conclusions about the ability of current theoretical expectations to predict such an important number.

  13. Present-day and future global bottom-up ship emission inventories including polar routes.

    PubMed

    Paxian, Andreas; Eyring, Veronika; Beer, Winfried; Sausen, Robert; Wright, Claire

    2010-02-15

    We present a global bottom-up ship emission algorithm that calculates fuel consumption, emissions, and vessel traffic densities for present-day (2006) and two future scenarios (2050) considering the opening of Arctic polar routes due to projected sea ice decline. Ship movements and actual ship engine power per individual ship from Lloyd's Marine Intelligence Unit (LMIU) ship statistics for six months in 2006 and further mean engine data from literature serve as input. The developed SeaKLIM algorithm automatically finds the most probable shipping route for each combination of start and destination port of a certain ship movement by calculating the shortest path on a predefined model grid while considering land masses, sea ice, shipping canal sizes, and climatological mean wave heights. The resulting present-day ship activity agrees well with observations. The global fuel consumption of 221 Mt in 2006 lies in the range of previously published inventories when undercounting of ship numbers in the LMIU movement database (40,055 vessels) is considered. Extrapolated to 2007 and ship numbers per ship type of the recent International Maritime Organization (IMO) estimate (100,214 vessels), a fuel consumption of 349 Mt is calculated which is in good agreement with the IMO total of 333 Mt. The future scenarios show Arctic polar routes with regional fuel consumption on the Northeast and Northwest Passage increasing by factors of up to 9 and 13 until 2050, respectively. PMID:20088494

  14. Pacific variability under present-day and Middle Miocene boundary conditions

    NASA Astrophysics Data System (ADS)

    Krapp, Mario; Jungclaus, Johann H.

    2015-05-01

    We use the coupled climate model MPI-ESM to show that for higher CO2 levels the El Niño-Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) merge into a single mode of Pacific variability, regardless of present-day or Middle Miocene (~15 Ma) topographic boundary conditions. Hence, topographic differences—determining the landscape of past climates—play a smaller role for Pacific variability than previously thought. We attribute the single variability mode to resonance between these two oscillation patterns. In order to estimate the strength of the resonance we compute the spectral power of the ENSO and PDO time series and their coherence. We find that for both Middle Miocene and present-day topographic conditions, higher CO2 forcing leads to stronger resonance between ENSO and PDO. Our results show that (1) stronger CO2 forcing enhances Pacific variability resulting in stronger "atmospheric bridge" and that (2) past climates are likely to exhibit Pacific variability corresponding either to ENSO, PDO, or our proposed single mode.

  15. Future droughts in Global Climate Models and adaptation strategies from regional present-day analogues

    NASA Astrophysics Data System (ADS)

    Orlowsky, B.; Seneviratne, S. I.

    2012-04-01

    Droughts are among the most impacting phenomena of a changing climate, affecting agricultural productivity and human health. They can furthermore interact with and amplify other climatic extreme events such as heat waves. Our analysis of the CMIP5 ensemble of GCM simulations identifies several hot spots of aggravating droughts in coming decades, such as the Mediterranean, parts of the Southern US and North East Brazil, which also compare well with increasing stress from heat waves. However, as we show by a comparison of drought indices, the exact pattern can substantially depend on the index choice. In some regions of the developing world which are particularly vulnerable to droughts, e.g. Central Africa, this uncertainty is further increased by a high disagreement between the GCMs. In a second step, we perform an analogue search which, for a given target region, identifies regions which under present-day climate show drought conditions that are similar to the projected future drought conditions of the target region. For example, the future conditions in the Mediterranean are found to be analogue to the present-day conditions in parts of the US, Central Asia or Australia. Information from web resources on climate change adaptation and agricultural practices for the identified similar regions are then assessed in the context of the target region as potential guidelines for adaptation. Thus combining the temporal and spatial dimension helps to transfer local climate adaptation knowledge to other regions, where it is expected to become relevant in the future.

  16. Present-day strain rates and dynamics of the East African Rift

    NASA Astrophysics Data System (ADS)

    Stamps, D. S.; Flesch, L. M.; Calais, E.

    2009-04-01

    The forces and physical processes at work during continental rifting remain to be fully understood and quantified. We investigate the balance of large-scale forces affecting present-day rifting in East Africa using a thin sheet approach to quantify strain rates and deviatoric stresses. We develop a strain rate model constrained by a combination of GPS-derived kinematic models and seismic moment tensors (CMT catalog) for our region of interest. We estimate a total deviatoric stress field by combining (1) stresses caused by gravitational potential energy (GPE) gradients within the crust and (2) a buoyancy signal present in the topography that we use to compute stresses. To estimate internal body forces, we assume crustal thicknesses and lateral density variations modeled in Crust 2.0 (G. Laske and G. Masters, http://mahi.ucsd.edu/Gabi/sediment.html, 2000). In our preferred model of deviatoric stresses, we estimate and remove the dynamic topography buoyancy signal by allowing the mantle lithosphere density to vary, compensating the lithosphere to a given reference depth. To test the reliability of our total deviatoric stress field, we compare tensor patterns of deviatoric stresses, with and without contributions from the mantle, to tensor patterns from kinematic deformation indicators. Our results to date suggest that horizontal buoyancy forces arising from variable crustal thicknesses and lateral density variations within the lithosphere contribute significantly to the diverging plate boundary forces of the EAR but do not account for the entire budget of force needed to produce present-day deformation.

  17. Present-day crustal deformation along the El Salvador Fault Zone from ZFESNet GPS network

    NASA Astrophysics Data System (ADS)

    Staller, Alejandra; Martínez-Díaz, José Jesús; Benito, Belén; Alonso-Henar, Jorge; Hernández, Douglas; Hernández-Rey, Román; Díaz, Manuel

    2016-02-01

    This paper presents the results and conclusions obtained from new GPS data compiled along the El Salvador Fault Zone (ESFZ). We calculated a GPS-derived horizontal velocity field representing the present-day crustal deformation rates in the ESFZ based on the analysis of 30 GPS campaign stations of the ZFESNet network, measured over a 4.5 year period from 2007 to 2012. The velocity field and subsequent strain rate analysis clearly indicate dextral strike-slip tectonics with extensional component throughout the ESFZ. Our results suggest that the boundary between the Salvadoran forearc and Caribbean blocks is a deformation zone which varies along the fault zone. We estimate that the movement between the two blocks is at least ~ 12 mm yr- 1. From west to east, this movement is variably distributed between faults or segments of the ESFZ. We propose a kinematic model with three main blocks; the Western, Central and Eastern blocks delimited by major faults. For the first time, we were able to provide a quantitative measure of the present-day horizontal geodetic slip rate of the main segments of ESFZ, ranging from ~ 2 mm yr- 1 in the east segment to ~ 8 mm yr- 1, in the west and central segments. This study contributes new kinematic and slip rate data that should be used to update and improve the seismic hazard assessments in northern Central America.

  18. A non-tectonic origin for the present day stress field in the sedimentary Paris Basin

    NASA Astrophysics Data System (ADS)

    Cornet, Francois; Magnenet, Vincent

    2016-04-01

    The large scale stress patterns observed in intraplate area is generally considered to result from far-field boundary forces that drive plate tectonics. However, no present day deformation has been detected in the Paris Basin, yet significant deviatoric stresses are measured in limestone formations observed above soft argillite layers encountered in this region at depths close to 500m. Further, the pore pressure measured in the argillite is larger than that measured in the surrounding permeable zones. These observations suggest a presently active source of stress in this sedimentary system. We propose that this stress is not related to tectonics but to pressure solution effects activated by pore pressure transients. These transients develop in the natural fracture system that affects the limestone formations. They are linked to climatic variations and involve periods that range from thousands to hundreds of thousands years. This mechanism generates time-dependent shear stresses in soft formations and explains overpressures observed in the very low permeability argillite. This mechanism may be modeled by different visco-elastic behaviors for the various formations. It outlines the influence of time dependent material properties on the present day stress field. These results imply that the viscoelastic properties of sedimentary formations raise a strong difficulty for extrapolating measured surface deformations to basement rocks in domains of very slow tectonics.

  19. Chemical interactions between the present-day Martian atmosphere and surface minerals

    NASA Technical Reports Server (NTRS)

    Prinn, Ronald; Fegley, Bruce

    1987-01-01

    Thermochemical and photochemical reactions between surface minerals and present-day atmospheric constituents are predicted to produce microscopic effects on the surfaces of mineral grains. Relevant reactions hypothesized in the literature include conversions of silicates and volcanic glasses to clay minerals, conversion of ferrous to ferric compounds, and formation of carbonates, nitrates, and sulfates. These types of surface-atmosphere interactions are important for addressing issues such as chemical weathering of minerals, biological potential of the surface environment, and atmospheric stability in both present and past Martian epochs. It is emphasized that the product of these reactions will be observable and interpretable on the microscopic surface layers of Martian surface rocks using modern techniques with obvious implications for sample return from Mars. Macroscopic products of chemical weathering reactions in past Martian epochs are also expected in Martian surface material. These products are expected not only as a result of reactions similar to those proceeding today but also due to aqueous reactions in past epochs in which liquid water was putatively present. It may prove very difficult or impossible however to determine definitively from the relic macroscopic product alone either the exact weathering process which led to its formation or the identity of its weathered parent mineral. The enormous advantages of studying Martian chemical weathering by investigating the microscopic products of present-day chemical reactions on sample surfaces are very apparent.

  20. Chemical interactions between the present-day Martian atmosphere and surface minerals: Implications for sample return

    NASA Technical Reports Server (NTRS)

    Prinn, Ronald; Fegley, Bruce

    1988-01-01

    Thermochemical and photochemical reactions between surface minerals and present-day atmospheric constituents are predicted to produce microscopic effects on the surface of mineral grains. Relevant reactions hypothesized in the literature include conversions of silicates and volcanic glasses to clay minerals, conversion of ferrous to ferric compounds, and formation of carbonates, nitrates, and sulfates. These types of surface-atmosphere weathering of minerals, biological potential of the surface environment, and atmospheric stability in both present and past Martian epochs. It is emphasized that the product of these reactions will be observable and interpretable on the microscopic surface layers of Martian surface rocks using modern techniques with obvious implications for sample return from Mars. Macroscopic products of chemical weathering reactions in past Martian epochs are also expected in Martian surface materials. These products are expected not only as a result of reactions similar to those proceeding today but also due to aqueous reactions in past epochs in which liquid water was putatively present. It may prove very difficult or impossible, however, to determine definitively from the relic macroscopic product alone either the exact weathering process which led to its formation of the identity of its weathering parent mineral. The enormous advantages of studying the Martian chemical weathering by investigating the microscopic products of present-day chemical reactions on sample surfaces are very apparent.

  1. Past- and present-day Madden-Julian Oscillation in CNRM-CM5

    NASA Astrophysics Data System (ADS)

    Song, Eun-Ji; Seo, Kyong-Hwan

    2016-04-01

    Madden-Julian Oscillation (MJO) in the past (nineteenth century) and present day (twentieth century) is examined using preindustrial and historical experiments of Centre National de Recherches Météorologiques-Coupled Models, version 5 (CNRM-CM5) in Coupled Model Intercomparison Project Phase 5 (CMIP5). The present-day MJO is stronger than the past MJO by 33% and it is ~10% more frequent. In particular, the MJO phases 4-7 signifying deep convection situated over the Maritime continent and western Pacific (WP) are considerably enhanced. These changes are due mainly to greenhouse gas forcing with little impact from nature forcing. Dynamical mechanisms for this change are investigated. A peculiar strengthening of MJO over WP comes from increased basic-state sea surface temperature (SST) over the Central Pacific (CP) and EP. The increase in precipitation over WP results from both the response to enhanced SST over CP and the inverted Walker circulation induced by the EP and CP SST increase. The latter causes a pair of anticyclonic Rossby waves straddling the equator, leading to moisture convergence over WP.

  2. Assessment of present day geomorphological dynamics to decipher landscape evolution around the Paleolithic sites of Melka Kunture, Ethiopia

    NASA Astrophysics Data System (ADS)

    Maerker, Michael; Schillaci, Calogero; Melis, Rita; Mussi, Margherita

    2014-05-01

    The area of Melka Kunture (central Ethiopia) is one of the most important clusters of Paleolithic sites in Eastern Africa. The archaeological record spans from c. 1.7 Ma onwards, with a number of stratified occurrences of Oldowan, Acheulean, Middle Stone Age and Late Stone Age industries, together with faunal remains and human fossils. However, the archaeological sites are endangered by flooding and soil erosion. The main excavation area lies close to the convergence of the Awash river with the Atabella river, one of the main tributaries of the upper Awash catchment. In the semi-arid Ethiopian highlands, gully networks develop especially in the vicinity of the active and inactive river meanders. Various erosion processes are linked to specific driving factors such as the rainfall regime, the land use/cover changes and vertic soils with a specific hydrological behaviour. It was documented in the field and by previous research that the origin of most of the man made erosion channels is due to animal pathways and car tracks. However, paleolandscape features increase the general erosion risk. Former wetland areas and deposition zones are particularly affected by soil erosion processes. Hence, the spatial distribution and characteristics of present day geomorphic processes also reveal information on the paleolandscape. In order to assess landscape evolution and present day geomorphologic dynamics, we mapped the geomorphology describing in detail the present-day slope processes at a 10.000 scale. We performed a detailed terrain analysis based on high resolution DEMs such as SRTM-X with 25m resolution and ALOS/PRISM with 10m resolution to characterize the main erosion processes and surface runoff dynamics. The latter ones are simulated using a Soil Conservation Service Curve Number method. Landuse was delineated for a larger area using ASTER 25m multispectral data. Finally, using calibrated topographic indices and a simple hydrological model we were able to detect and

  3. Present-Day Surface Changes on Mars: Implications for Recent Climate Variability and Habitability

    NASA Astrophysics Data System (ADS)

    McEwen, A. S.; Dundas, C. M.; Diniega, S.; Byrne, S.; Bridges, N. T.; Hansen, C. J.

    2012-12-01

    With the high-resolution and repeat-image capability of MRO/HiRISE, we have been documenting present-day surface activity. This activity includes seasonal defrosting (spots, fans, etc.), changes in polar deposits, new impacts, migrating sand dunes, enlargement of gullies, and a variety of slope flows. What does this tell us about possible environmental change and habitability? Perhaps the key result is that previous suggestions of recent climate change on Mars may have been somewhat exaggerated. One such suggestion is that the enlargement of pits in the south polar residual cap indicates present-day global warming. However, recent models of continuous sublimation and redeposition of the CO2 predict a suite of landforms that have been observed to exist today (Byrne, 2009, AREPS 37, 535). Another suggestion is that mid-latitude gullies formed by melting snow or shallow ice after a recent period of high obliquity, but HiRISE observations have shown rapid and widespread gully activity in the present climate (Diniega et al., 2010, Geology 38, 1047; Dundas et al., 2012, Icarus 220, 124; Dundas et al., this conference). Likewise, suggestions that Mars needed a significantly higher atmospheric density to explain the presence of well-preserved sand dunes have been countered by observations of widespread current activity (Bridges et al., 2012, Geology 40, 31; Bridges et al., 2012, Nature 485, 339). These observations do not rule out significantly different past climate conditions but do suggest that their effects were less pronounced, at least in recent times. There are features that do not appear active today; one example is the transverse aeolian ridges. Also, the mid-latitude icy lobate flows and ice-rich mantles have not shown current activity, appear to have partially sublimated, and are likely remnants of recent past climates. Ground ice excavated by new craters is observed closer to the equator than predicted for the present atmospheric water vapor content, but

  4. Three-dimensional instantaneous dynamics modeling of present-day Aegean subduction

    NASA Astrophysics Data System (ADS)

    Glerum, Anne; Thieulot, Cedric; Pranger, Casper; van Hinsbergen, Douwe; Fraters, Menno; Spakman, Wim

    2015-04-01

    The Aegean region (Eastern Mediterranean) is exemplary of the interaction between crustal tectonics, plate motion, subduction and mantle flow: African subduction underneath the region has been continuous for at least the last 100 My, leading to about 2100-2500 km of subducted lithosphere residing in the mantle (van Hinsbergen et al., 2005). During this subduction, decoupled upper continental and oceanic crust accreted into a wedge of stacked nappes. In turn, these nappes have been significantly extended, predominantly during the last 25 My, due to the retreat of the African slab relative to Eurasia (van Hinsbergen and Schmid, 2012). As a first step to better understanding the coupling of the tectonic evolution of the crust and the underlying mantle dynamics, we are developing 3-D numerical models of the instantaneous dynamics of the present-day Aegean subduction system using the finite element code ASPECT (Kronbichler et al., 2012). The instantaneous models are set up with initial slab geometries derived from tomography and realistic plate boundary configurations and incorporate the major crustal weak zones of the overriding plate. Our modeling results in predictions of flow fields and stress, strain rate and rotation rate fields for the present-day tectonic setting of the Aegean region. By comparing our various model predictions to the widely available observations, such as focal mechanisms, GPS velocities and seismic anisotropy, we aim at an improved understanding of how mantle flow, subduction morphology and possibly slab segmentation, as well as the rheological behavior of the overriding plate, control present-day tectonic deformation. We expect to show preliminary results of this comparison. Kronbichler, M., Heister, T. and Bangerth, W. (2012), High Accuracy Mantle Convection Simulation through Modern Numerical Methods, Geophysical Journal International, 191, 12-29. Van Hinsbergen, D. J. J., Hafkenscheid, E., Spakman, W., Meulenkamp, J. E. and Wortel, R. (2005

  5. Modelling economic losses of historic and present-day high-impact winter storms in Switzerland

    NASA Astrophysics Data System (ADS)

    Welker, Christoph; Martius, Olivia; Stucki, Peter; Bresch, David; Dierer, Silke; Brönnimann, Stefan

    2015-04-01

    Windstorms can cause significant financial damage and they rank among the most hazardous meteorological hazards in Switzerland. Risk associated with windstorms involves the combination of hazardous weather conditions, such as high wind gust speeds, and socio-economic factors, such as the distribution of assets as well as their susceptibilities to damage. A sophisticated risk assessment is important in a wide range of areas and has benefits for e.g. the insurance industry. However, a sophisticated risk assessment needs a large sample of storm events for which high-resolution, quantitative meteorological and/or loss data are available. Latter is typically an aggravating factor. For present-day windstorms in Switzerland, the data basis is generally sufficient to describe the meteorological development and wind forces as well as the associated impacts. In contrast, historic windstorms are usually described by graphical depictions of the event and/or by weather and loss reports. The information on historic weather events is overall sparse and the available historic weather and loss reports mostly do not provide quantitative information. It has primarily been the field of activity of environmental historians to study historic weather extremes and their impacts. Furthermore, the scarce availability of atmospheric datasets reaching back sufficiently in time has so far limited the analysis of historic weather events. The Twentieth Century Reanalysis (20CR) ensemble dataset, a global atmospheric reanalysis currently spanning 1871 to 2012, offers potentially a very valuable resource for the analysis of historic weather events. However, the 2°×2° latitude-longitude grid of the 20CR is too coarse to realistically represent the complex orography of Switzerland, which has considerable ramifications for the representation of smaller-scale features of the surface wind field influenced by the local orography. Using the 20CR as a starting point, this study illustrates a method to

  6. Larval therapy from antiquity to the present day: mechanisms of action, clinical applications and future potential

    PubMed Central

    Whitaker, Iain S; Twine, Christopher; Whitaker, Michael J; Welck, Mathew; Brown, Charles S; Shandall, Ahmed

    2007-01-01

    When modern medicine fails, it is often useful to draw ideas from ancient treatments. The therapeutic use of fly larvae to debride necrotic tissue, also known as larval therapy, maggot debridement therapy or biosurgery, dates back to the beginnings of civilisation. Despite repeatedly falling out of favour largely because of patient intolerance to the treatment, the practice of larval therapy is increasing around the world because of its efficacy, safety and simplicity. Clinical indications for larval treatment are varied, but, in particular, are wounds infected with multidrug‐resistant bacteria and the presence of significant co‐morbidities precluding surgical intervention. The flies most often used in larval therapy are the facultative calliphorids, with the greenbottle blowfly (Lucilia sericata) being the most widely used species. This review summarises the fascinating and turbulent history of larval therapy from its origin to the present day, including mechanisms of action and evidence for its clinical applications. It also explores future research directions. PMID:17551073

  7. Pole of rotating analysis of present-day Juan de Fuca plate motion

    NASA Technical Reports Server (NTRS)

    Nishimura, C.; Wilson, D. S.; Hey, R. N.

    1984-01-01

    Convergence rates between the Juan de Fuca and North American plates are calculated by means of their relative, present-day pole of rotation. A method of calculating the propagation of errors in addition to the instantaneous poles of rotation is also formulated and applied to determine the Euler pole for Pacific-Juan de Fuca. This pole is vectorially added to previously published poles for North America-Pacific and 'hot spot'-Pacific to obtain North America-Juan de Fuca and 'hot spot'-Juan de Fuca, respectively. The errors associated with these resultant poles are determined by propagating the errors of the two summed angular velocity vectors. Under the assumption that hot spots are fixed with respect to a mantle reference frame, the average absolute velocity of the Juan de Puca plate is computed at approximately 15 mm/yr, thereby making it the slowest-moving of the oceanic plates.

  8. Cloud properties in the present-day tropical climate: EC-EARTH model biases

    NASA Astrophysics Data System (ADS)

    Lacagnina, C.; Selten, F.

    2012-04-01

    Observations are compared with the observed SST forced and coupled simulation performed by the EC-EARTH climate model. We use different diagnostic tools to investigate model biases in simulating marine cloud properties at different spatial and time scales in the present-day (1985 to 2001) tropical climate. The model underestimates the thick low-cloud amount and their contribution to the reflection of the solar radiation. In general, most of the simulated cloud types are too bright. As a result, the net cloud cooling effect is often overestimated, except over the subsidence cold pools. Furthermore, our model fails to reproduce the correlations between low-cloud fraction and mid-tropospheric pressure velocity (ω500) and SST changes during El Niño. In addition, some indications lead to infer EC-EARTH does not properly reproduce the impact of the Walker circulation shifts on the CRF fluctuations in the interannual variability.

  9. Ancient human genomes suggest three ancestral populations for present-day Europeans.

    PubMed

    Lazaridis, Iosif; Patterson, Nick; Mittnik, Alissa; Renaud, Gabriel; Mallick, Swapan; Kirsanow, Karola; Sudmant, Peter H; Schraiber, Joshua G; Castellano, Sergi; Lipson, Mark; Berger, Bonnie; Economou, Christos; Bollongino, Ruth; Fu, Qiaomei; Bos, Kirsten I; Nordenfelt, Susanne; Li, Heng; de Filippo, Cesare; Prüfer, Kay; Sawyer, Susanna; Posth, Cosimo; Haak, Wolfgang; Hallgren, Fredrik; Fornander, Elin; Rohland, Nadin; Delsate, Dominique; Francken, Michael; Guinet, Jean-Michel; Wahl, Joachim; Ayodo, George; Babiker, Hamza A; Bailliet, Graciela; Balanovska, Elena; Balanovsky, Oleg; Barrantes, Ramiro; Bedoya, Gabriel; Ben-Ami, Haim; Bene, Judit; Berrada, Fouad; Bravi, Claudio M; Brisighelli, Francesca; Busby, George B J; Cali, Francesco; Churnosov, Mikhail; Cole, David E C; Corach, Daniel; Damba, Larissa; van Driem, George; Dryomov, Stanislav; Dugoujon, Jean-Michel; Fedorova, Sardana A; Gallego Romero, Irene; Gubina, Marina; Hammer, Michael; Henn, Brenna M; Hervig, Tor; Hodoglugil, Ugur; Jha, Aashish R; Karachanak-Yankova, Sena; Khusainova, Rita; Khusnutdinova, Elza; Kittles, Rick; Kivisild, Toomas; Klitz, William; Kučinskas, Vaidutis; Kushniarevich, Alena; Laredj, Leila; Litvinov, Sergey; Loukidis, Theologos; Mahley, Robert W; Melegh, Béla; Metspalu, Ene; Molina, Julio; Mountain, Joanna; Näkkäläjärvi, Klemetti; Nesheva, Desislava; Nyambo, Thomas; Osipova, Ludmila; Parik, Jüri; Platonov, Fedor; Posukh, Olga; Romano, Valentino; Rothhammer, Francisco; Rudan, Igor; Ruizbakiev, Ruslan; Sahakyan, Hovhannes; Sajantila, Antti; Salas, Antonio; Starikovskaya, Elena B; Tarekegn, Ayele; Toncheva, Draga; Turdikulova, Shahlo; Uktveryte, Ingrida; Utevska, Olga; Vasquez, René; Villena, Mercedes; Voevoda, Mikhail; Winkler, Cheryl A; Yepiskoposyan, Levon; Zalloua, Pierre; Zemunik, Tatijana; Cooper, Alan; Capelli, Cristian; Thomas, Mark G; Ruiz-Linares, Andres; Tishkoff, Sarah A; Singh, Lalji; Thangaraj, Kumarasamy; Villems, Richard; Comas, David; Sukernik, Rem; Metspalu, Mait; Meyer, Matthias; Eichler, Evan E; Burger, Joachim; Slatkin, Montgomery; Pääbo, Svante; Kelso, Janet; Reich, David; Krause, Johannes

    2014-09-18

    We sequenced the genomes of a ∼7,000-year-old farmer from Germany and eight ∼8,000-year-old hunter-gatherers from Luxembourg and Sweden. We analysed these and other ancient genomes with 2,345 contemporary humans to show that most present-day Europeans derive from at least three highly differentiated populations: west European hunter-gatherers, who contributed ancestry to all Europeans but not to Near Easterners; ancient north Eurasians related to Upper Palaeolithic Siberians, who contributed to both Europeans and Near Easterners; and early European farmers, who were mainly of Near Eastern origin but also harboured west European hunter-gatherer related ancestry. We model these populations' deep relationships and show that early European farmers had ∼44% ancestry from a 'basal Eurasian' population that split before the diversification of other non-African lineages. PMID:25230663

  10. Meteoritic parent bodies - Nature, number, size and relation to present-day asteroids

    NASA Technical Reports Server (NTRS)

    Lipschutz, Michael E.; Gaffey, Michael J.; Pellas, Paul

    1989-01-01

    The relationship between meteoritic parent bodies and the present-day asteroids is discussed. Results on oxygen isotopic signatures and chemical distinctions among meteorite classes indicate that meteorites derive from a small number of parent bodies relative to the number of asteroids. The spectral properties of the ordinary chondrites and similar inclusions in meteoritic breccias differ from those of the abundant S asteroids (with no process known that can account for these differences); the closest spectral analogs of these chondrites are the rare near-earth Q-type asteroids. These facts lead to the question of why abundant meteorites have rare asteroidal analogs, while the abundant asteroids have rare meteoritic analogs. This question constitutes a prime topic for future studies.

  11. The Combined Landscape of Denisovan and Neanderthal Ancestry in Present-Day Humans.

    PubMed

    Sankararaman, Sriram; Mallick, Swapan; Patterson, Nick; Reich, David

    2016-05-01

    Some present-day humans derive up to ∼5% [1] of their ancestry from archaic Denisovans, an even larger proportion than the ∼2% from Neanderthals [2]. We developed methods that can disambiguate the locations of segments of Denisovan and Neanderthal ancestry in present-day humans and applied them to 257 high-coverage genomes from 120 diverse populations, among which were 20 individual Oceanians with high Denisovan ancestry [3]. In Oceanians, the average size of Denisovan fragments is larger than Neanderthal fragments, implying a more recent average date of Denisovan admixture in the history of these populations (p = 0.00004). We document more Denisovan ancestry in South Asia than is expected based on existing models of history, reflecting a previously undocumented mixture related to archaic humans (p = 0.0013). Denisovan ancestry, just like Neanderthal ancestry, has been deleterious on a modern human genetic background, as reflected by its depletion near genes. Finally, the reduction of both archaic ancestries is especially pronounced on chromosome X and near genes more highly expressed in testes than other tissues (p = 1.2 × 10(-7) to 3.2 × 10(-7) for Denisovan and 2.2 × 10(-3) to 2.9 × 10(-3) for Neanderthal ancestry even after controlling for differences in level of selective constraint across gene classes). This suggests that reduced male fertility may be a general feature of mixtures of human populations diverged by >500,000 years. PMID:27032491

  12. Is Present Day Continental Deformation Nearly Plate-Like? If so, Why?

    NASA Astrophysics Data System (ADS)

    Thatcher, W.

    2001-12-01

    Some indicators of deformation (seismicity, late Cenozoic faulting, regional topographic relief) suggest broad deformation zones. However, space geodetic mappings of current movements and Holocene fault distributions often show straining focussed in very narrow zones. Conventional wisdom has it that continental deformation is spread over broad regions while straining of oceanic lithosphere occurs in narrow zones. Here I present evidence, largely from recent GPS surveys, suggesting present day continental deformation is actually occurring in a largely plate-like manner through the relative motions of a small number of micro-plates within each deforming zone, sometimes perturbed by isolated zones of deformation driven by local lithospheric density gradients. How can this be so? I speculate that this behavior is caused by the inherent lateral heterogeneity of continental lithosphere and by frictional and ductile weakening and strengthening mechanisms that promote focussed deformation that migrates with time. Qualitative indications of active deformation can sometimes be misleading. In many active regions erosion and tectonism are in balance and very low rates of slip on inclined faults can generate significant steady-state topography. However, in currently inactive regions, erosion rates are very low, much less than rates of vertical movement in even moderately active deforming zones. Therefore landscape relief provides evidence for current activity but preserves it over long periods, millions to tens of millions of years (Ma) (e.g. Alps, Rocky Mountains). Secondly, background seismicity is a qualitative measure of tectonic activity and only the largest earthquakes contribute significantly to representative long term deformation rates, so the spatial distribution of all smaller events can be misleading. Finally, many mappings of `active' faults encompass features up to several Ma old that are not necessarily representative of current activity. In contrast, late

  13. How large are present-day heat flow variations across Mars' surface?

    NASA Astrophysics Data System (ADS)

    Plesa, Ana-Catalina; Tosi, Nicola; Grott, Matthias; Breuer, Doris

    2015-04-01

    The upcoming InSight (Interior exploration using Seismic Investigations, Geodesy and Heat Transport) mission, to be launched in 2016, will carry the first in-situ Martian heat flow measurement and provide an important baseline to constrain the present-day heat budget of the planet and, in turn, the thermal and chemical evolution of its interior. Currently, the Earth and the Moon are the only bodies on which in-situ surface heat flow measurements have been performed. Here, strong spatial variations of the surface heat flow are primarily caused by plate tectonics and the heterogeneous distribution of heat producing elements over the surface (e.g., the so-called Procellarum KREEP Terrane PKT on the lunar nearside). In the absence of plate-tectonics and large-scale geochemical anomalies, on Mars, surface heat flow is expected to vary less with geological location, being mainly influenced by variations in the thickness and HPE content of the crust [1], and by mantle plumes [2]. We have tested this assumption by running thermal evolution models for Mars in 3D spherical geometry, using the mantle convection code Gaia [3]. In our calculations, we employ a crust of fixed thickness with a north-south dichotomy in crustal thickness, a low conductivity compared to the mantle and enriched in radiogenic heat producing elements. Our results show that including compressibility effects, phase transitions and different core sizes, surface heat flow variations are mainly dominated by the crust contribution, unless the mantle viscosity increases more than three orders of magnitude with depth. In the latter case, heat flow variations due to mantle upwellings are ~ 8 mW/m2 relative to surface average and remain confined to limited surface regions. Both surface heat flow variations on Mars obtained from numerical models and the heat flow measurement planned for the InSight mission will permit to address the question of a possible plume underneath Elysium and also to test the feasibility

  14. Present-day serpentinization in the Tablelands, Gros Morne National Park, Newfoundland: a Mars Analogue Site

    NASA Astrophysics Data System (ADS)

    Szponar, N.; Morrill, P. L.; Brazelton, W. J.; Schrenk, M. O.; Bower, D. M.; Steele, A.

    2010-12-01

    Serpentinization - a reaction between water and ultramafic rock (derived from the mantle) - is suspected to be a source of hydrocarbons such as methane on Mars. Through the hydration of ultramafic rock, this reaction produces hydrogen (H2) gas and reducing conditions necessary for abiogenic hydrocarbon synthesis, while also producing conditions amendable for the production of methane through microbial chemoautotrophic pathways. Mars analogue sites of present-day serpentinization can be used to determine what geochemical measurements are required for determining the reactions responsible for the methane in the Martian atmosphere. On Earth few locations that are known to exhibit active serpentinization are easily accessible. One such location is found in the Tablelands at Gros Morne National Park, Newfoundland. Peridotite rocks similar to those found on Mars dominate the Tablelands thus making the Tablelands an important analogue site for potential ecosystems on Mars. Present-day serpentinization is evidenced by fluid seeps characterized by highly alkaline (pH 11 to 12) and highly reducing (as low as -820 mV) conditions, travertine and the presence of dissolved methane. These fluids contain high concentrations of Ca2+ (~5.00x104ppb) compared to freshwater inputs (~ 1.00x103) and react at the surface with atmospheric CO2 producing travertine deposits (as CaCO3 precipitate). Dissolved H2 gas produced abiogenically through the serpentinization reaction also provides copious geofuels, which can be used for chemosynthesis. Preliminary data has shown that microbial life lives in the high pH springs of the Tablelands. Ongoing studies of targeted compounds including phospholipid fatty acids and ether-linked lipids are being used to determine the microbial community compositions and verify the occurrence of Bacteria and Archaea in these fluids. An important question is also the source of the serpentinized fluid seeps. Hydrogen (δ2H) and oxygen (δ18O) isotopes of these

  15. Improved Present Day Euler Vector for the Sierra Nevada Block Using GPS

    NASA Astrophysics Data System (ADS)

    Psencik, K. O.; Dixon, T. H.; Schmalzle, G.; McQuarrie, N.; McCaffery, R.

    2006-12-01

    We present a new surface velocity field for California and Nevada (UM-CANVAS) and use it to solve for a new angular velocity for the rigid Sierra Nevada-Great Valley block. We use all publicly available GPS data for this region, from both continuous (CGPS) and episodic campaign (EGPS) sites. All data were re-processed to create a consistent velocity field. Site velocities are referenced to both stable North America and the central Basin and Range. The Sierra Nevada block is a relatively long, narrow block, bounded on the west by the San Andreas Fault, on the east by a complex fault system comprising the Eastern California Shear Zone and the Walker Lane Belt, and on the south by the Garlock fault. The northern extent of the block is not well defined. The new data along with a strain accumulation algorithm may help to define this boundary. Published estimates for the motion of Sierra Nevada block include clockwise, counter-clockwise, and no rotation relative to stable North America; the new velocity data may also help to resolve this discrepancy. To better understand the motion of the Sierra Nevada block over time, we compare our model of present day motion to a geologic model of block motion over the last 2-3 Ma (McQuarrie and Wernicke, 2005). McQuarrie, N. and B. Wernicke, An Animated tectonic reconstruction of southwestern North America since 36 Ma. Geosphere, V.1; no.3; 147-172; 2005.

  16. Present-day deformation of northern Pakistan from Salt Ranges to Karakorum Ranges

    NASA Astrophysics Data System (ADS)

    Jouanne, F.; Awan, A.; Pêcher, A.; Kausar, A.; Mugnier, J. L.; Khan, I.; Khan, N. A.; Van Melle, J.

    2014-03-01

    Episodic GPS measurements are used to quantify the present-day velocity field in the northwestern Himalaya from the southern Pamir to the Himalayan foreland. We report large postseismic displacements following the 2005 Kashmir earthquake and several mm/yr thrusting of the central segment of the Salt Ranges and Potwar Plateau over the foreland, westward thrusting of Nanga Parbat above the Kohistan Plateau, and ~12 mm/yr SSE velocities of the Karakorum Ranges and of the Deosai and Kohistan Plateaus relative to the Indian Plate. Numerical simulations allow to determine a first approximation of slip along active faults: (1) substantial creep of ~87 mm/yr between 2006 and 2012 along the flat northeast of the Balakot-Bagh Thrust affected by the 2005 earthquake; (2) ~5 mm/yr slip of the central segment of the Salt Ranges and Potwar Plateau, whereas their western boundaries are clearly inactive over the time span covered by our measurements; (3) 13 mm/yr ductile slip along the Main Himalayan Thrust modeled by a dislocation dipping 7° northward, locked at a depth of 15 km; and (4) ~20 mm/yr slip along the shear zone forming the western boundary of Nanga Parbat, between depths of 1.6 and 6.5 km. Residuals velocities suggest the existence of left-lateral strike slip along the Jhelum Fault.

  17. Global hotspots in the present-day distribution of ancient animal and plant lineages.

    PubMed

    Procheş, Şerban; Ramdhani, Syd; Perera, Sandun J; Ali, Jason R; Gairola, Sanjay

    2015-01-01

    The current distribution of biotic lineages that emerged in the deep time has both theoretical and practical implications, in particular for understanding the processes that have forged present-day biodiversity and informing local and regional-scale conservation efforts. To date however, there has been no examination of such patterns globally across taxa and geological time. Here we map the diversity of selected extant seed plant and tetrapod vertebrate lineages that were already in existence either in the latest Triassic or latest Cretaceous. For Triassic-age lineages, we find concentrations in several regions - both tropical and temperate - parts of North America, Europe, East and South-east Asia, northern South America, and New Zealand. With Cretaceous-age lineages, high values are relatively uniformly distributed across the tropics, with peak the values along the Andes, in South-east Asia and Queensland, but also in the temperate Cape Mountains. These patterns result from a combination of factors, including land area, geographic isolation, climate stability and mass extinction survival ability. While the need to protect many of these lineages has been long recognised, a spatially-explicit approach is critical for understanding and maintaining the factors responsible for their persistence, and this will need to be taken forward across finer scales. PMID:26498226

  18. The history of time and frequency from antiquity to the present day

    NASA Astrophysics Data System (ADS)

    Levine, Judah

    2016-04-01

    I will discuss the evolution of the definitions of time, time interval, and frequency from antiquity to the present day. The earliest definitions of these parameters were based on a time interval defined by widely observed apparent astronomical phenomena, so that techniques of time distribution were not necessary. With this definition, both time, as measured by clocks, and frequency, as realized by some device, were derived quantities. On the other hand, the fundamental parameter today is a frequency based on the properties of atoms, so that the situation is reversed and time and time interval are now derived quantities. I will discuss the evolution of this transition and its consequences. In addition, the international standards of both time and frequency are currently realized by combining the data from a large number of devices located at many different laboratories, and this combination depends on (and is often limited by) measurements of the times of clocks located at widely-separated laboratories. I will discuss how these measurements are performed and how the techniques have evolved over time.

  19. Recovery of a geocentric reference frame using the present-day GPS system

    NASA Technical Reports Server (NTRS)

    Malla, Rajendra P.; Wu, Sien-Chong

    1990-01-01

    A geocentric reference frame adopts the center of mass of the earth as the origin of the coordinate axes. The center of mass of the earth is the natural and unambiguous origin of a geocentric satellite dynamical system. But in practice a kinematically obtained terrestrial reference frame may assume an origin other than the geocenter. The establishment of a geocentric reference frame, to which all relevant observations and results can be referred and in which geodynamic theories or models for the dynamic behavior of earth can be formulated, requires the ability to accurately recover a given coordinate frame origin offset from the geocenter. GPS measurements, because of their abundance and broad distribution, provide a powerful tool to obtain this origin offset in a short period of time. Two effective strategies have been devised. Data from the First Central And South America (Casa Uno) geodynamics experiment has been studied, in order to demonstrate the ability of recovering the geocenter location with present day GPS satellites and receivers.

  20. Challenges in constraining anthropogenic aerosol effects on cloud radiative forcing using present-day spatiotemporal variability

    NASA Astrophysics Data System (ADS)

    Ghan, Steven; Wang, Minghuai; Zhang, Shipeng; Ferrachat, Sylvaine; Gettelman, Andrew; Griesfeller, Jan; Kipling, Zak; Lohmann, Ulrike; Morrison, Hugh; Neubauer, David; Partridge, Daniel G.; Stier, Philip; Takemura, Toshihiko; Wang, Hailong; Zhang, Kai

    2016-05-01

    A large number of processes are involved in the chain from emissions of aerosol precursor gases and primary particles to impacts on cloud radiative forcing. Those processes are manifest in a number of relationships that can be expressed as factors dlnX/dlnY driving aerosol effects on cloud radiative forcing. These factors include the relationships between cloud condensation nuclei (CCN) concentration and emissions, droplet number and CCN concentration, cloud fraction and droplet number, cloud optical depth and droplet number, and cloud radiative forcing and cloud optical depth. The relationship between cloud optical depth and droplet number can be further decomposed into the sum of two terms involving the relationship of droplet effective radius and cloud liquid water path with droplet number. These relationships can be constrained using observations of recent spatial and temporal variability of these quantities. However, we are most interested in the radiative forcing since the preindustrial era. Because few relevant measurements are available from that era, relationships from recent variability have been assumed to be applicable to the preindustrial to present-day change. Our analysis of Aerosol Comparisons between Observations and Models (AeroCom) model simulations suggests that estimates of relationships from recent variability are poor constraints on relationships from anthropogenic change for some terms, with even the sign of some relationships differing in many regions. Proxies connecting recent spatial/temporal variability to anthropogenic change, or sustained measurements in regions where emissions have changed, are needed to constrain estimates of anthropogenic aerosol impacts on cloud radiative forcing.

  1. Present-day stress-field in the Cooper basin of Australia: implications for petroleum exploration

    NASA Astrophysics Data System (ADS)

    Backé, G.; King, R.

    2010-12-01

    The Cooper Basin is located in centre part of the Australian continent, 5000km away from the nearest plate boundary. This Late Carboniferous to Middle Triassic basin is the largest onshore sedimentary basin producing oil and gas in Australia - mostly by fraccing tight reservoirs. Thus, an extensive database is available for studying the in-situ stress field in the basin. Previous studies have shown a significant variability if the stress field across the basin. However, the development of the mostly tight prospects require a good understanding of the structure of the reservoirs, mechanical properties of the stratigraphy, fracture geometry and density, in-situ stress field and fracture stimulation strategies in order to maximise the production This study provides new in-situ stress data from borehole breakouts and drilling-induced tensile fractures, along with a description of the fractures present along the well trajectory. The geometry of the natural fault and fracture network is interpreted from 3D seismic data, and compared to the well data. Finally, we performed a series of numeric simulation to test the fault and fracture stability in the present-day stress field. These data and our interpretation are used to evaluate the geomechanical properties of the Cooper Basin. This method is reproducible to other oil-bearing basins around the world, but is also applicable to the development of engineered geothermal reservoir or evaluation of carbon dioxide storage site.

  2. Simulation of Net Infiltration for Present-Day and Potential Future Climates

    SciTech Connect

    D. Levitt

    2004-11-09

    The purpose of this model report is to document the infiltration model used to estimate upper-bound, mean, and lower-bound spatially-distributed average annual net infiltration rates for present-day and potential future climates at Yucca Mountain, Nevada. Net infiltration is the component of infiltrated precipitation, snowmelt, or surface water run-on that has percolated below the zone of evapotranspiration as defined by the depth of the effective root zone. The estimates of net infiltration are primarily used for defining the upper boundary condition for the site-scale three-dimensional unsaturated zone (UZ) model. The UZ flow model is one of several process models abstracted by the total system performance assessment (TSPA) model used to evaluate performance of the repository at Yucca Mountain, Nevada. The net-infiltration model is important for assessing repository-system performance because output from this model provides the upper boundary condition for the UZ flow model used to generate flow fields; water percolating downward from the UZ will be the principal means by which radionuclides are potentially released to the saturated zone (SZ). The SZ is the principal pathway to the biosphere where the reasonably maximally exposed individual (RMEI) is exposed to radionuclides.

  3. Global hotspots in the present-day distribution of ancient animal and plant lineages

    PubMed Central

    Procheş, Şerban; Ramdhani, Syd; Perera, Sandun J.; Ali, Jason R.; Gairola, Sanjay

    2015-01-01

    The current distribution of biotic lineages that emerged in the deep time has both theoretical and practical implications, in particular for understanding the processes that have forged present-day biodiversity and informing local and regional-scale conservation efforts. To date however, there has been no examination of such patterns globally across taxa and geological time. Here we map the diversity of selected extant seed plant and tetrapod vertebrate lineages that were already in existence either in the latest Triassic or latest Cretaceous. For Triassic-age linages, we find concentrations in several regions – both tropical and temperate – parts of North America, Europe, East and South-east Asia, northern South America, and New Zealand. With Cretaceous-age lineages, high values are relatively uniformly distributed across the tropics, with peak the values along the Andes, in South-east Asia and Queensland, but also in the temperate Cape Mountains. These patterns result from a combination of factors, including land area, geographic isolation, climate stability and mass extinction survival ability. While the need to protect many of these lineages has been long recognised, a spatially-explicit approach is critical for understanding and maintaining the factors responsible for their persistence, and this will need to be taken forward across finer scales. PMID:26498226

  4. Present-Day Genetic Structure of Atlantic Salmon (Salmo salar) in Icelandic Rivers and Ice-Cap Retreat Models

    PubMed Central

    Olafsson, Kristinn; Pampoulie, Christophe; Hjorleifsdottir, Sigridur; Gudjonsson, Sigurdur; Hreggvidsson, Gudmundur O.

    2014-01-01

    Due to an improved understanding of past climatological conditions, it has now become possible to study the potential concordance between former climatological models and present-day genetic structure. Genetic variability was assessed in 26 samples from different rivers of Atlantic salmon in Iceland (total of 2,352 individuals), using 15 microsatellite loci. F-statistics revealed significant differences between the majority of the populations that were sampled. Bayesian cluster analyses using both prior information and no prior information on sampling location revealed the presence of two distinguishable genetic pools - namely, the Northern (Group 1) and Southern (Group 2) regions of Iceland. Furthermore, the random permutation of different allele sizes among allelic states revealed a significant mutational component to the genetic differentiation at four microsatellite loci (SsaD144, Ssa171, SSsp2201 and SsaF3), and supported the proposition of a historical origin behind the observed variation. The estimated time of divergence, using two different ABC methods, suggested that the observed genetic pattern originated from between the Last Glacial Maximum to the Younger Dryas, which serves as additional evidence of the relative immaturity of Icelandic fish populations, on account of the re-colonisation of this young environment following the Last Glacial Maximum. Additional analyses suggested the presence of several genetic entities which were likely to originate from the original groups detected. PMID:24498283

  5. Effects of Present-Day Ice Melting on the Geodetic Measurements in Southeast Alaska

    NASA Astrophysics Data System (ADS)

    Sato, T.; Larsen, C. F.; Miura, S.; Ohta, Y.; Fujimoto, H.; Sun, W.; Sugano, T.; Kaufman, A. M.; Freymueller, J. T.

    2008-12-01

    It is known that the southeast Alaska (SE-AK) is undergoing a rapid land uplift, which is considered to be mainly due to the effect of melting of past ice, especially in the last two hundred years after the little ice age (LIA). The crustal deformation caused by the post-glacial rebound (PGR) has been clearly detected by GPS and tidal gauge measurements and modeled (Larsen et al., 2004 and 2005). On the other hand, it is considered also that the observed uplift rate is affected by the present-day ice melting (PDIM), which is considered to be the effect of recent global warming (Larsen et al., 2005; Sato et al., 2006). The displacement measurements provide us useful information to evaluate the ice-melting rate and to discuss the viscosity of the earth. However, usually, it is difficult to separate the uplift rate due to the long- term viscous response of the earth by only using displacement observations, because the two effects (i.e. the elastic and viscous deformations) are mixed in the observed data. Related to this problem, Wahr et al. (1995) demonstrated a method to separate the viscous contribution from the observed data by collocating position and gravity measurements. Considered this, since 2006, we, a joint team of Japanese and U.S. researchers are carrying out the absolute gravity (AG) measurements once a year adding to the temporal and continuous GPS observations in SE-AK. Combining the AG measurements and GPS measurements is useful because the attraction part of gravity measurement is sensitive to a mass change of the present-day ice melting, while the past-ices should have no effect to the attraction part of the observed gravity change. In this context of the discussion, precise numerical estimation of the PDIM effect is important (Sato et al., 2007). Based on the two kinds of DEM (Digital Elevation Model), i.e. one is from the 2000 Shuttle Radar Topography Mission (SRTM) and other is that from air photo dating data which were obtained in the period of

  6. Challenges in constraining anthropogenic aerosol effects on cloud radiative forcing using present-day spatiotemporal variability

    PubMed Central

    Ghan, Steven; Wang, Minghuai; Zhang, Shipeng; Ferrachat, Sylvaine; Gettelman, Andrew; Griesfeller, Jan; Kipling, Zak; Lohmann, Ulrike; Morrison, Hugh; Neubauer, David; Partridge, Daniel G.; Stier, Philip; Takemura, Toshihiko; Wang, Hailong; Zhang, Kai

    2016-01-01

    A large number of processes are involved in the chain from emissions of aerosol precursor gases and primary particles to impacts on cloud radiative forcing. Those processes are manifest in a number of relationships that can be expressed as factors dlnX/dlnY driving aerosol effects on cloud radiative forcing. These factors include the relationships between cloud condensation nuclei (CCN) concentration and emissions, droplet number and CCN concentration, cloud fraction and droplet number, cloud optical depth and droplet number, and cloud radiative forcing and cloud optical depth. The relationship between cloud optical depth and droplet number can be further decomposed into the sum of two terms involving the relationship of droplet effective radius and cloud liquid water path with droplet number. These relationships can be constrained using observations of recent spatial and temporal variability of these quantities. However, we are most interested in the radiative forcing since the preindustrial era. Because few relevant measurements are available from that era, relationships from recent variability have been assumed to be applicable to the preindustrial to present-day change. Our analysis of Aerosol Comparisons between Observations and Models (AeroCom) model simulations suggests that estimates of relationships from recent variability are poor constraints on relationships from anthropogenic change for some terms, with even the sign of some relationships differing in many regions. Proxies connecting recent spatial/temporal variability to anthropogenic change, or sustained measurements in regions where emissions have changed, are needed to constrain estimates of anthropogenic aerosol impacts on cloud radiative forcing. PMID:26921324

  7. Present-day antarctic climatology of the NCAR community climate model version 1

    SciTech Connect

    Tzeng, Renyow; Bromwich, D.H. ); Parish, T.R. )

    1993-02-01

    Five-year seasonal cycle output produced by the NCAR Community Climate Model Version 1 (CCM 1) with R15 resolution is used to evaluate the ability of the model to simulate the present-day climate of Antarctica. The model results are compared with observed horizontal syntheses and point data. Katabatic winds, surface temperatures over the continent, the circumpolar trough, the vertical motion field, the split jet stream over the Pacific Ocean, and the snowfall accumulation are analyzed. The results show that the CCM1 with R15 resolution can simulate to some extent the dynamics of Antarctic climate not only for the synoptic scale, but also for some mesoscale features. This is reflected in the zonal-mean pattern of vertical motion by the presence of two convergence centers. The finding suggests that the CCM I might also capture the split jet stream over New Zealand in winter, but the evidence is mixed. This is inferred to be due to inadequate simulation of the thermal forcing over high southern latitudes. The CCM I can also capture the phase and amplitude of the annual and semiannual variation of temperature, sea level pressure, and zonally averaged zonal (E-W) wind. That the CCM 1 can simulate some characteristics of the semiannual variation may be due to the improved radiation treatment compared to the earlier CCMO. The most dramatic shortcomings were associated with the model's anomalously large precipitation amounts at high latitudes. The simulations of cloudiness and the atmospheric heat balance are adversely affected. A greatly refined moisture budget scheme is needed to eliminate these problems and may allow the split jet-stream feature over the New Zealand area in winter to be accurately reproduced. A coupled mesoscale-CCM 1 model may be needed to simulate the feedback from mesoscale cyclones to synoptic-scale weather systems, and the katabatic wind circulation.

  8. Quantifying present-day and long-term shale weathering rates across a latitudinal climosequence

    NASA Astrophysics Data System (ADS)

    Dere, A. L. D.; Andrews, E.; White, T. S.

    2015-12-01

    A transect of shale sites was established across the Northern Hemisphere as part of the Susquehanna Shale Hills Critical Zone Observatory (SSHO) to investigate the role of climate in shale weathering. Mean annual temperature and precipitation vary across sites located in Wales, New York, Pennsylvania, Virginia, Tennessee, Alabama and Puerto Rico. Long-term weathering rates were quantified by comparing bulk soil geochemistry with original parent shale composition and cosmogenic 10Be inventories to estimate weathering duration. Present-day weathering rates were obtained by burying approximately 2 cm by 1 cm shale chips at multiple depths in soil pit walls. Shale chip samples were exhumed after two and five years of burial, washed and mass loss measured. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to determine surface chemistry and physical alteration of the recovered shale. Long-term weathering rates increase with increasing temperature across the transect. Similarly, after two years of burial, exhumed shale chip weathering rates increased from 2.9 ± 0.9 in Wales to 11.2 ± 3.7 m Ma-1 in Puerto Rico. Average weathering rates after two years of burial were similar in Virginia, Tennessee and Alabama (8.6 - 10.6 m Ma-1). Many shale chips in Alabama and Puerto Rico, however, retained soil particles even after washing, therefore total mass loss, and thus weathering rates, at these sites could be even greater. After five years of burial, mass loss across the Appalachian sites was greatest in Tennessee while weathering rates were overall generally similar to two year rates (3.0 to 12.6 m Ma-1). Evidence of physical and chemical changes, especially Na and Mg loss, from shale chip surfaces was greater on shale chips buried at warmer and wetter sites. Quantifying weathering rates as a function of climate at multiple scales will contribute to understanding the effects of global climate change on soil formation rates in the Critical

  9. A test of present-day plate geometries for northeast Asia and Japan

    NASA Technical Reports Server (NTRS)

    Demets, Charles

    1992-01-01

    Alternative geometries for the present-day configuration of plate boundaries in northeast Asia and Japan are tested using NUVEL-1 and 256 horizontal earthquake slip vectors from the Japan and northern Kuril trenches. Statistical analysis of the slip vectors is used to determine whether the North American, Eurasian, or Okhotsk plate overlies the trench. Along the northern Kuril trench, slip vectors are well-fit by the NUVEL-1 Pacific-North America Euler pole, but are poorly fit by the Pacific-Eurasia Euler pole. Results for the Japan trench are less conclusive, but suggest that much of Honshu and Hokkaido are also part of the North American plate. The simplest geometry consistent with the trench slip vectors is a geometry in which the North American plate extends south to 41 deg N, and possibly includes northern Honshu and southern Hokkaido. Although these results imply that the diffuse seismicity that connects the Lena River delta to Sakhalin Island and the eastern Sea of Japan records motion between Eurasia and North America, onshore geologic and seismic data define an additional belt of seismicity in Siberia that cannot be explained with this geometry. Assuming that these two seismic belts constitute evidence for an Okhotsk block, two published kinematic models for motion of the Okhotsk block are tested. The first model, which predicts motion of up to 15 mm/yr relative to North America, is rejected because Kuril and Japan trench slip vectors are fit more poorly than for the simpler geometry described above. The second model gives a good fit to the trench slip vectors, but only if Okhotsk-North America motion is slower than 5 mm/yr.

  10. Uncovering the Genetic History of the Present-Day Greenlandic Population

    PubMed Central

    Moltke, Ida; Fumagalli, Matteo; Korneliussen, Thorfinn S.; Crawford, Jacob E.; Bjerregaard, Peter; Jørgensen, Marit E.; Grarup, Niels; Gulløv, Hans Christian; Linneberg, Allan; Pedersen, Oluf; Hansen, Torben; Nielsen, Rasmus; Albrechtsen, Anders

    2015-01-01

    Because of past limitations in samples and genotyping technologies, important questions about the history of the present-day Greenlandic population remain unanswered. In an effort to answer these questions and in general investigate the genetic history of the Greenlandic population, we analyzed ∼200,000 SNPs from more than 10% of the adult Greenlandic population (n = 4,674). We found that recent gene flow from Europe has had a substantial impact on the population: more than 80% of the Greenlanders have some European ancestry (on average ∼25% of their genome). However, we also found that the amount of recent European gene flow varies across Greenland and is far smaller in the more historically isolated areas in the north and east and in the small villages in the south. Furthermore, we found that there is substantial population structure in the Inuit genetic component of the Greenlanders and that individuals from the east, west, and north can be distinguished from each other. Moreover, the genetic differences in the Inuit ancestry are consistent with a single colonization wave of the island from north to west to south to east. Although it has been speculated that there has been historical admixture between the Norse Vikings who lived in Greenland for a limited period ∼600–1,000 years ago and the Inuit, we found no evidence supporting this hypothesis. Similarly, we found no evidence supporting a previously hypothesized admixture event between the Inuit in East Greenland and the Dorset people, who lived in Greenland before the Inuit. PMID:25557782

  11. Present-day deformation of the intra-Eurasian plate regions

    NASA Astrophysics Data System (ADS)

    Garcia Sancho, Candela; Govers, Rob; Tesauro, Magdala

    2015-04-01

    , and paleomagnetic observations, which capture present-day and long-term deformation. We discuss various causes for differences.

  12. Challenges in constraining anthropogenic aerosol effects on cloud radiative forcing using present-day spatiotemporal variability.

    PubMed

    Ghan, Steven; Wang, Minghuai; Zhang, Shipeng; Ferrachat, Sylvaine; Gettelman, Andrew; Griesfeller, Jan; Kipling, Zak; Lohmann, Ulrike; Morrison, Hugh; Neubauer, David; Partridge, Daniel G; Stier, Philip; Takemura, Toshihiko; Wang, Hailong; Zhang, Kai

    2016-05-24

    A large number of processes are involved in the chain from emissions of aerosol precursor gases and primary particles to impacts on cloud radiative forcing. Those processes are manifest in a number of relationships that can be expressed as factors dlnX/dlnY driving aerosol effects on cloud radiative forcing. These factors include the relationships between cloud condensation nuclei (CCN) concentration and emissions, droplet number and CCN concentration, cloud fraction and droplet number, cloud optical depth and droplet number, and cloud radiative forcing and cloud optical depth. The relationship between cloud optical depth and droplet number can be further decomposed into the sum of two terms involving the relationship of droplet effective radius and cloud liquid water path with droplet number. These relationships can be constrained using observations of recent spatial and temporal variability of these quantities. However, we are most interested in the radiative forcing since the preindustrial era. Because few relevant measurements are available from that era, relationships from recent variability have been assumed to be applicable to the preindustrial to present-day change. Our analysis of Aerosol Comparisons between Observations and Models (AeroCom) model simulations suggests that estimates of relationships from recent variability are poor constraints on relationships from anthropogenic change for some terms, with even the sign of some relationships differing in many regions. Proxies connecting recent spatial/temporal variability to anthropogenic change, or sustained measurements in regions where emissions have changed, are needed to constrain estimates of anthropogenic aerosol impacts on cloud radiative forcing. PMID:26921324

  13. Generation of harmonic frequencies and their effects in present day ICRF systems

    NASA Astrophysics Data System (ADS)

    Durodié, F.; Vervier, M.

    1999-09-01

    The whole TEXTOR-94 ICRF system [1,2] circuit has been analyzed, partially modelled and studied at the fundamental operating frequency and, more important, at harmonic frequencies thereof. It has been found that without appropriate measures, present day systems and especially the TEXTOR ICRF system are prone to spurious generation of power at the second harmonic frequency. This leads either to erroneous activation of the reflected power safety protection or to highly increased (in some cases doubled) voltages in the transmission lines and antennas. As the voltage standing waves at the second harmonic displace the total voltage maxima in the transmission lines and antennas, this also explains why arcs are not always found at the expected voltage maxima for the fundamental frequency. The model is also able to give additional explanations why the ASDEX-Upgrade ICRF system has dramatically improved its power handling capabilities after the introduction of the ``3dB coupler reflection compensation scheme'' [3,4]. The output of one of the TEXTOR transmitters has been fitted with a quarter wave length shorted stub which has no effect on the operation at the fundamental frequency but which effectively shorts out the second harmonic. It has to be noted that eg. the Tore Supra RDL [5] antennas are fitted with such a stub in the feeding transmission line whose function is to enter cooling water into the transmission line system. Hence, this could be the explanation of the apparent higher than average power handling capabilities of the TS antenna system. Experimental results clearly indicate a much improved operational power handling capability on plasma and an increased voltage stand-off when conditioning this antenna pair on vacuum. Limits have yet to be explored but already remarkable is the fact that since the installation of the quarter wavelength stub the reflected power safety system has been activated only once and furthermore so in poorly matched conditions.

  14. Present-day climate of Antarctica : A study with a regional atmospheric climate model

    NASA Astrophysics Data System (ADS)

    van de Berg, W. J.

    2008-02-01

    The present-day climate of Antarctica is studied with a regional climate model. In this research, foci are the surface mass balance, i.e. the accumulation of snow on the ice cap, and the heat budget of the atmosphere above Antarctica. Insight in the surface mass balance of the Antarctic ice cap is gained by explanation, evaluation and subsequently calibration of model-simulated surface mass balance patterns using more than 1900 in situ observations. Furthermore, a method is developed to quantify the uncertainty in the local and spatially integrated surface mass balance estimate. In our study, a good correlation between the observations and model results is found, giving reliability to the results presented. The final surface mass balance estimate primarily deviates in the coastal zones of Antarctica from earlier estimates. Our results strongly suggest much higher accumulation rates than previously assumed, leading to a 15% higher overall accumulation. Unfortunately, the coastal zone is poorly covered by observations, which makes a final assessment difficult. Analysis of the heat budget of the Antarctic atmosphere clarifies the dynamics of the Antarctic boundary layer and shows the coupling to the global climate. Our results show how the boundary layer develops from the interior of Antarctica to the coast; from shallow and extremely stable to deeper, mixed but still stable. Furthermore, the effect of surface undulations on the local near surface temperature is explained. Domes and ridges have a weakening effect on the surface inversion of the temperature through enhanced divergence of the near-surface wind field. Oppositely, valleys strengthen the surface inversion. This coupling of topography and temperature causes the spatial variability of surface temperatures on scales of typical a few hundred kilometers.

  15. Uncovering the genetic history of the present-day Greenlandic population.

    PubMed

    Moltke, Ida; Fumagalli, Matteo; Korneliussen, Thorfinn S; Crawford, Jacob E; Bjerregaard, Peter; Jørgensen, Marit E; Grarup, Niels; Gulløv, Hans Christian; Linneberg, Allan; Pedersen, Oluf; Hansen, Torben; Nielsen, Rasmus; Albrechtsen, Anders

    2015-01-01

    Because of past limitations in samples and genotyping technologies, important questions about the history of the present-day Greenlandic population remain unanswered. In an effort to answer these questions and in general investigate the genetic history of the Greenlandic population, we analyzed ∼200,000 SNPs from more than 10% of the adult Greenlandic population (n = 4,674). We found that recent gene flow from Europe has had a substantial impact on the population: more than 80% of the Greenlanders have some European ancestry (on average ∼25% of their genome). However, we also found that the amount of recent European gene flow varies across Greenland and is far smaller in the more historically isolated areas in the north and east and in the small villages in the south. Furthermore, we found that there is substantial population structure in the Inuit genetic component of the Greenlanders and that individuals from the east, west, and north can be distinguished from each other. Moreover, the genetic differences in the Inuit ancestry are consistent with a single colonization wave of the island from north to west to south to east. Although it has been speculated that there has been historical admixture between the Norse Vikings who lived in Greenland for a limited period ∼600-1,000 years ago and the Inuit, we found no evidence supporting this hypothesis. Similarly, we found no evidence supporting a previously hypothesized admixture event between the Inuit in East Greenland and the Dorset people, who lived in Greenland before the Inuit. PMID:25557782

  16. Statistical dynamical downscaling of present day and future precipitation regimes in southern Vietnam

    NASA Astrophysics Data System (ADS)

    Schubert, David; Reyers, Mark; Pinto, Joaquim; Fink, Andreas; Massmeyer, Klaus

    2016-04-01

    Southeast Asia has been identified as one of the hot-spots of climate change. While the projected changes in annual precipitation are comparatively small, there is a clear tendency towards more rainfall in the dry season and an increase in extreme precipitation events. In this study, a statistical dynamical downscaling (SDD) approach is applied to obtain higher resolution and more robust regional climate change projections for tropical Southeast Asia with focus on Vietnam. First, a recent climate (RC) simulation with the regional climate model COSMO-CLM with a spatial resolution of ~50 km driven by ERA-Interim (1979-2008) is performed for the tropical region of Southeast Asia. For the SDD, six weather types (WTs) are selected for Vietnam during the wet season (April - October) using a k-means cluster analysis of daily zonal wind component in 850 hPa and 200 hPa from the RC run. For each calculated weather type, simulated representatives are selected from the RC run and are then further dynamically downscaled to a resolution of 0.0625° (7 km). By using historical WT frequencies, the simulated representatives are recombined to a high resolution rainfall climatology for the recent climate. It is shown that the SDD is generally able to capture the present day climatology and that the employment of the higher resolved simulated representatives enhances the performance of the SDD. However, an overestimation of rainfall at higher altitudes is found. To obtain future climate projections, an ensemble of eight CMIP5 model members are selected to study precipitation changes. For these projections, WT frequencies of future scenarios under two representative Concentration Pathways (RCP4.5 and RCP8.5) are taken into account for the mid-term scenario (2046-2065) and the long-term scenario (2081-2100). The strongest precipitation changes are found for the RCP8.5 scenario. Most of the models indicate a generally increase in precipitation amount in the wet period over Southeast

  17. Present-day loading rates of faults in the northern Mojave region, California, from GPS Geodesy

    NASA Astrophysics Data System (ADS)

    Spinler, J. C.; Bennett, R. A.; McGill, S. F.

    2013-12-01

    We analyzed GPS data from 45 continuous sites along with 9 campaign sites within the northern Mojave region for the time period 2002.0-2013.0 to model the present-day crustal velocity field for the region. In addition to the 54 sites we analyzed, we included 21 site velocities from the USGS Fort Irwin network and 66 site velocities from the SCEC Crustal Motion Map 4 velocity field. We rotated the USGS and SCEC velocities into our Stable North America Reference Frame (SNARF) through a minimization of the differences amongst sites in common between the different solutions. We used our velocities to constrain an elastic block model in order to estimate fault-loading rates of crustal faults within the northern Mojave region. Each crustal block is allowed to both translate and rotate about a vertical axis. Results include new slip rate estimates for the NW-SE oriented right-lateral strike-slip faults within the eastern California shear zone (ECSZ), including model faults representing the Lenwood-Lockhart fault zone (4.5×0.2 mm/yr), Calico-Blackwater faults (1.0×0.4 mm/yr), and Goldstone Lake fault (1.2×0.5 mm/yr), with a total slip across the ECSZ of ~8-9 mm/yr, lower than some previous geodetic estimates, but slightly higher than geologic estimates. We estimate left-lateral slip rates of 4.4×0.2 and 4.9×0.3 mm/yr for the model faults representing the west-central and central segments of the Garlock fault, respectively, with rates decreasing to 0.5×0.4 mm/yr for the easternmost segment. We estimate clockwise rotation rates of the crustal blocks in the Northeast Mojave domain in the range of 3-5×0.7 °/Myr, consistent with paleomagnetic estimates of as much as 50° since 10 Ma.

  18. Liquid Water Lakes on Mars Under Present-Day Conditions: Sustainability and Effects on the Subsurface

    NASA Astrophysics Data System (ADS)

    Goldspiel, Jules M.

    2015-11-01

    Decades of Mars exploration have produced ample evidence that aqueous environments once existed on the surface. Much evidence supports groundwater emergence as the source of liquid water on Mars [1-4]. However, cases have also been made for rainfall [5] and snow pack melts [6].Whatever the mechanism by which liquid water is emplaced on the surface of Mars, whether from groundwater seeps, atmospheric precipitation, or some combination of sources, this water would have collected in local topographic lows, and at least temporarily, would have created a local surface water system with dynamic thermal and hydrologic properties. Understanding the physical details of such aqueous systems is important for interpreting the past and present surface environments of Mars. It is also important for evaluating potential habitable zones on or near the surface.In conjunction with analysis of surface and core samples, valuable insight into likely past aqueous sites on Mars can be gained through modeling their formation and evolution. Toward that end, we built a 1D numerical model to follow the evolution of small bodies of liquid water on the surface of Mars. In the model, liquid water at different temperatures is supplied to the surface at different rates while the system is subjected to diurnally and seasonally varying environmental conditions. We recently simulated cases of cold (275 K) and warm (350 K) water collecting in a small depression on the floor of a mid southern latitude impact crater. When inflows create an initial pool > 3 m deep and infiltration can be neglected, we find that the interior of the pool can remain liquid over a full Mars year under the present cold and dry climate as an ice cover slowly thickens [7]. Here we present new results for the thermal and hydrologic evolution of surface water and the associated subsurface region for present-day conditions when infiltration of surface water into the subsurface is considered.[1] Pieri (1980) Science 210.[2] Carr

  19. Estimating hypothetical present-day insured losses for past intense hurricanes in the French Antilles

    NASA Astrophysics Data System (ADS)

    Thornton, James; Desarthe, Jérémy; Naulin, Jean-Philippe; Garnier, Emmanuel; Liu, Ye; Moncoulon, David

    2015-04-01

    On the islands of the French Antilles, the period for which systematic meteorological measurements and historic event loss data are available is short relative to the recurrence intervals of very intense, damaging hurricanes. Additionally, the value of property at risk changes through time. As such, the recent past can only provide limited insight into potential losses from extreme storms in coming years. Here we present some research that seeks to overcome, as far as is possible, the limitations of record length in assessing the possible impacts of near-future hurricanes on insured properties. First, using the archives of the French overseas departments (which included administrative and weather reports, inventories of damage to houses, crops and trees, as well as some meteorological observations after 1950) we reconstructed the spatial patterns of hazard intensity associated with three historical events. They are: i) the 1928 Hurricane (Guadeloupe), ii) Hurricane Betsy (1956, Guadeloupe) and iii) Hurricane David (1979, Martinique). These events were selected because all were damaging, and the information available on each is rich. Then, using a recently developed catastrophe model for hurricanes affecting Guadeloupe, Martinique, Saint-Barthélemy and Saint-Martin, we simulated the hypothetical losses to insured properties that the reconstructed events might cause if they were to reoccur today. The model simulated damage due to wind, rainfall-induced flooding and storm surge flooding. These 'what if' scenarios provided an initial indication of the potential present-day exposure of the insurance industry to intense hurricanes. However, we acknowledge that historical events are unlikely to repeat exactly. We therefore extended the study by producing a stochastic event catalogue containing a large number of synthetic but plausible hurricane events. Instrumental data were used as a basis for event generation, but importantly the statistical methods we applied permit

  20. Importance of Past Human and Natural Disturbance in Present-Day Net Ecosystem Productivity

    NASA Astrophysics Data System (ADS)

    Felzer, B. S.; Phelps, P.

    2014-12-01

    Gridded datasets of Net Ecosystem Exchange derived from eddy covariance and remote sensing measurements provide a means of validating Net Ecosystem Productivity (NEP, opposite of NEE) from terrestrial ecosystem models. While most forested regions in the U.S. are observed to be moderate to strong carbon sinks, models not including human or natural disturbances will tend to be more carbon neutral, which is expected of mature ecosystems. We have developed the Terrestrial Ecosystems Model Hydro version (TEM-Hydro) to include both human and natural disturbances to compare against gridded NEP datasets. Human disturbances are based on the Hurtt et al. (2006) land use transition dataset and include transient agricultural (crops and pasture) conversion and abandonment and timber harvest. We include natural disturbances of storms and fires based on stochastic return intervals. Tropical storms and hurricane return intervals are based on Zheng et al. (2009) and occur only along the U.S. Atlantic and Gulf coasts. Fire return intervals are based on LANDFIRE Rapid Assessment Vegetation Models and vegetation types from the Hurtt dataset. We are running three experiments with TEM-Hydro from 1700-2011 for the conterminous U.S.: potential vegetation (POT), human disturbance only (agriculture and timber harvest, LULC), and human plus natural disturbance (agriculture, timber harvest, storms, and fire, DISTURB). The goal is to compare our NEP values to those obtained by FLUXNET-MTE (Jung et al. 2009) from 1982-2008 and ECMOD (Xiao et al., 2008) from 2000-2006 for different plant functional types (PFTs) within the conterminous U.S. Preliminary results show that, for the entire U.S., potential vegetation yields an NEP of 10.8 gCm-2yr-1 vs 128.1 gCm-2yr-1 for LULC and 89.8 gCm-2yr-1 for DISTURB from 1982-2008. The effect of regrowth following agricultural and timber harvest disturbance therefore contributes substantially to the present-day carbon sink, while stochastic storms and fires

  1. Present-Day 3D Velocity Field of Eastern North America Based on Continuous GPS Observations

    NASA Astrophysics Data System (ADS)

    Goudarzi, Mohammad Ali; Cocard, Marc; Santerre, Rock

    2016-07-01

    The Saint Lawrence River valley in eastern Canada was studied using observations of continuously operating GPS (CGPS) stations. The area is one of the most seismically active regions in eastern North America characterized by many earthquakes, which is also subject to an ongoing glacial isostatic adjustment. We present the current three-dimensional velocity field of eastern North America obtained from more than 14 years (9 years on average) of data at 112 CGPS stations. Bernese GNSS and GITSA software were used for CGPS data processing and position time series analysis, respectively. The results show the counterclockwise rotation of the North American plate in the No-Net-Rotation model with the average of 16.8 ± 0.7 mm/year constrained to ITRF 2008. We also present an ongoing uplift model for the study region based on the present-day CGPS observations. The model shows uplift all over eastern Canada with the maximum rate of 13.7 ± 1.2 mm/year and subsidence to the south mainly over northern USA with a typical rate of -1 to -2 mm/year and the minimum value of -2.7 ± 1.4 mm/year. We compared our model with the rate of radial displacements from the ICE-5G model. Both models agree within 0.02 mm/year at the best stations; however, our model shows a systematic spatial tilt compared to ICE-5G. The misfits between two models amount to the maximum relative subsidence of -6.1 ± 1.1 mm/year to the east and maximum relative uplift of 5.9 ± 2.7 mm/year to the west. The intraplate horizontal velocities are radially outward from the centers of maximum uplift and are inward to the centers of maximum subsidence with the typical velocity of 1-1.6 ± 0.4 mm/year that is in agreement with the ICE-5G model to the first order.

  2. Present-day Tectonic Stress Regimes in Northern Iraq and Surrounding Regions from Focal Mechanism Data

    NASA Astrophysics Data System (ADS)

    Mahdi, H. H.; Abdulnaby, W.; Al-Shukri, H. J.; Numan, N.

    2013-12-01

    The collision zone between the Arabian and the Eurasian plates is one of the most seismically active regions. Northern Iraq represents the northeastern part of the Arabian plate that has a suture zone with the Turkish and Iranian plates named Bitlis-Zagros suture zone. The present-day tectonic stress regimes can be estimated from focal mechanism data. The waveform moment tensor inversion method was used to derive the focal mechanism solution of 65 earthquakes with magnitudes of ≥3.5. Green's functions for the local and regional seismograms were generated in order to perform the moment tensor inversion using complete seismograms. From focal mechanism solutions, the direction of slip and the orientations of the moment tensor axes (P, N, and T) on the fault surface during an earthquake were determined. The tectonic stress regime of each focal mechanism was estimated based on Zoback (1992). The results show that all six categories of the stress regimes, which are normal faulting (NF), normal faulting with strike-slip component (NS), strike-slip faulting (SS), thrust faulting with strike-slip component (TS), thrust faulting (TF), and unknown or oblique faulting (UF), exist. However, the most common tectonic regimes in the study area are the SS (43.94%), UF (27.27%), and TF (13.64%). In most cases, the strike-slip movement on the fault surfaces consists of left-lateral movement. The NF regime, which is located in one small area near Diyala city at the Iraq-Iran border, might be a local tensional stress regime. The directions of the compressional stress axes show that the stress regime at the Zagros suture zone has two directions. One is perpendicular to the suture near the Iraq-Iran border, and the second is parallel to the suture near the Iraq-Turkey border. In addition, the compressional stress axes at the city of Sinjar, near the Iraq-Syria border, have E-W direction. These results are compatible with the tectonic setting of the Arabain-Eurasian continental

  3. A No-Net-Rotation Model of Present-Day Surface Motions

    NASA Astrophysics Data System (ADS)

    Kreemer, C.; Holt, W. E.

    2001-12-01

    A significant portion of the Earth's surface consists of zones of diffuse deformation. The interior regions of these diffuse zones of deformation move at distinctly different velocities from that of adjacent plates, and, because of their complexities, have been ignored in previous no-net-rotation (NNR) models (e.g., NNR-NUVEL1A). We have calculated a new NNR model from a continuous velocity field that incorporates both rigid plate motion and velocity gradients within plate boundary zones. The velocity field is obtained through a bi-cubic Bessel interpolation of almost 3000 geodetic velocities and strain rates inferred from Quaternary faults. The geodetic velocities are taken from about 50 different, mainly published, studies. For each study we have not adopted the original reference frame. Instead, we have solved for a rigid body rotation for each study that rotate the vectors of each study into a model reference frame in the process of satisfying a least-squares fit between model and observed velocities and model and observed strain rates. When compared with earlier NNR models we find significantly different angular velocities for many plates in our model. Differences between the NNR model presented here and earlier NNR models can be attributed to both the effect of including velocity gradients in diffuse plate boundary zones, as well as actual differences between geodetically derived, present-day, surface motions and geologic estimates. We find that for the Indian, Arabian, Nazca, Cocos, Philippine Sea, and the Caribbean plate the differences between our model and the NNR-NUVEL1A model are mainly due to differences between geodetic and geologic plate velocities. For the Eurasian plate the discrepancy that we find between our result and NNR-NUVEL1A model can not only be ascribed to the difference between geodetic and geologic velocities, but also to the significant effect of including plate boundary zones. The significantly different NNR rotation vectors that we

  4. Present-Day 3D Velocity Field of Eastern North America Based on Continuous GPS Observations

    NASA Astrophysics Data System (ADS)

    Goudarzi, Mohammad Ali; Cocard, Marc; Santerre, Rock

    2016-03-01

    The Saint Lawrence River valley in eastern Canada was studied using observations of continuously operating GPS (CGPS) stations. The area is one of the most seismically active regions in eastern North America characterized by many earthquakes, which is also subject to an ongoing glacial isostatic adjustment. We present the current three-dimensional velocity field of eastern North America obtained from more than 14 years (9 years on average) of data at 112 CGPS stations. Bernese GNSS and GITSA software were used for CGPS data processing and position time series analysis, respectively. The results show the counterclockwise rotation of the North American plate in the No-Net-Rotation model with the average of 16.8 ± 0.7 mm/year constrained to ITRF 2008. We also present an ongoing uplift model for the study region based on the present-day CGPS observations. The model shows uplift all over eastern Canada with the maximum rate of 13.7 ± 1.2 mm/year and subsidence to the south mainly over northern USA with a typical rate of -1 to -2 mm/year and the minimum value of -2.7 ± 1.4 mm/year. We compared our model with the rate of radial displacements from the ICE-5G model. Both models agree within 0.02 mm/year at the best stations; however, our model shows a systematic spatial tilt compared to ICE-5G. The misfits between two models amount to the maximum relative subsidence of -6.1 ± 1.1 mm/year to the east and maximum relative uplift of 5.9 ± 2.7 mm/year to the west. The intraplate horizontal velocities are radially outward from the centers of maximum uplift and are inward to the centers of maximum subsidence with the typical velocity of 1-1.6 ± 0.4 mm/year that is in agreement with the ICE-5G model to the first order.

  5. Potential autotrophic metabolisms in ultra-basic reducing springs associated with present-day continental serpentinization

    NASA Astrophysics Data System (ADS)

    Morrill, P. L.; Miles, S.; Kohl, L.; Kavanagh, H.; Ziegler, S. E.; Brazelton, W. J.; Schrenk, M. O.

    2013-12-01

    Ultra-basic reducing springs at continental sites of serpentinization act as windows into the biogeochemistry of this subsurface exothermic environment rich in H2 and CH4 gases. Biogeochemical carbon transformations in these systems are of interest because serpentinization creates conditions that are amenable to abiotic and biotic reduction of carbon. However, little is known about the metabolic capabilities of the microorganisms that live in this environment. To determine the potential for autotrophic metabolisms, bicarbonate and CO substrate addition microcosm experiments were performed using water and sediment from an ultra-basic reducing spring in the Tablelands, Newfoundland, Canada, a site of present-day continental serpentinization. CO was consistently observed to be utilized in the Live but not the Killed controlled replicates amended with 10% 13C labelled CO and non-labelled (natural C isotope abundance) CO. In the Live CO microcosms with natural C isotope abundance, the residual CO became enriched in 13C (~10 ‰) consistent with a decrease in the fraction of CO remaining. In the Killed CO controlled replicates with natural C isotope abundance the CO showed little 13C enrichment (~1.3 ‰). The data from the Live CO microcosms were well described by a Rayleigh isotopic distillation model, yielding an isotopic enrichment factor for microbial CO uptake of 15.7 ×0.5 ‰ n=2. These data suggest that there was microbial CO utilization in these experiments. The sediment and water from the 13C-labelled and non-labelled, Live and Killed microcosms were extracted for phospholipid fatty acids (PLFAs) to determine changes in community composition between treatments as well as to determine the microbial uptake of CO. The difference in community composition between the Live and Killed microcosms was not readily resolvable based on PLFA distributions. Additionally, the microbial uptake of 13CO had minimal to no affect on the δ13C of the cellular biomarkers, with the

  6. Influence of ocean tide dynamics on the climate system from the Cretaceous to present day

    NASA Astrophysics Data System (ADS)

    Weber, Tobias; Thomas, Maik

    2016-04-01

    Global numerical ocean models used for paleo-climate reconstructions generally only consider the ocean's general circulation, but neglect tidal dynamics. However, it has been demonstrated that tidally induced friction at the ocean bottom alters the mean ocean circulation and energy fluxes on timescales larger than one tidal period and up to climate timescales. Thereby the mean ocean circulation and temperature advection is altered and can thus affect climate. We simultaneously modeled the ocean's general circulation and tidal dynamics for five time-slices from the Cretaceous to present day: the Albian (ca. 110 million years ago, Ma), the Cenomanian-Turonian Boundary (ca. 93 Ma, CTB), the early Eocene (ca. 55 Ma), the early Pliocene (ca. 3.5 Ma), and a pre-industrial period (ca. 1850 AD). These simulations show that the tectonic evolution of ocean basins changes the resonance conditions in the paleo-oceans over time and thus the position of amphydromic systems and the amplitudes of partial tides. Largest amplitudes of the M2 partial tide are obtained during the early Eocene when they are in the global mean by 150% larger than in the CTB, when amplitudes are smallest. The evolution of the tidal system leads to an individual interaction between tidal dynamics and the ocean general circulation for all time-slices. In the Albian a reduction of horizontal velocities of up to 50% is simulated in the deep Indo-Pacific Throughflow (IPT) below 1000m depth. This reduction is the product of tidal residual mean currents induced by tidal waves propagating from the Pacific Ocean into the Indian Ocean that oppose the prevailing eastward thermohaline currents. In all other time-slices mainly an increase in horizontal transports is simulated. In the CTB both tidal residual mean currents (less than 0.2cm/s in most of the ocean) and the general ocean circulation (less than 0.5cm/s) are small, thus leading to a tidally induced increase by 50% in horizontal velocities in almost half of

  7. Present-Day Seasonal Gully Activity in a South Polar Pit (Sisyphi Cavi) on Mars

    NASA Astrophysics Data System (ADS)

    Raack, Jan; Reiss, Dennis; Appéré, Thomas; Vincendon, Mathieu; Ruesch, Ottaviano; Hiesinger, Harald

    2014-05-01

    Seasonal activity of gullies under current climatic conditions on Mars was observed by [1-7]. Dundas et al. [2] reviewed the present-day activity of classical gullies (including the gully presented in this work), dune gullies, and other mass wasting processes in the southern hemisphere on Mars. Recent polar gullies in Sisyphi Cavi were also analyzed by [8], who estimated ages of about 20 ka to 20 Ma for the gullies. In this study we focus on a single gully in Sisyphi Cavi, located in the south polar region at 1.44° E and 68.54° S. The gully occurs on the gullied equator-facing slope of an isolated polar pit within an infilled impact crater. Multi-temporal high-resolution image data analyses show new deposits at the terminus of the gully channel and on the gully apron within spring (after solar longitudes of 236°) of martian years (MY) 29 and 31. In MY 29 deposition of material shortens the channel by about 40 m; in MY 31 a new deposit at the western flank of the gully apron with approximately 300-600 m3 of material is visible [3]. Our morphological investigations show that the identified new deposits were formed by dark flows through the entire gully deposited on top of the apron between LS ~218° and ~226°. Thermal data show a temperature increase between solar longitudes (LS) ~218° and ~226°. Near-infrared spectral data show relatively constant band strengths of CO2 ice and H2O ice in this time range. After the formation of the dark flows (after LS ~226°), temperatures increase rapidly from ~180 K to >~270 K at LS ~250°. At this time, spectral data indicate that all volatiles on the surface sublimated. However, an earlier beginning of sublimation when the dark flows were observed (between LS ~218° and ~226°) is likely, due to the fact that the instruments can only show the last phase of sublimation (decrease of volatile band strengths) [3]. Spectral modeling shows that from winter to mid-spring, the surface of the studied area is covered by CO2 slab

  8. Sedimentary Mounds on Mars: Tracing Present-day Formation Processes into the Past

    NASA Technical Reports Server (NTRS)

    Niles, P. B.; Michalski, J.; Edwards, C. S.

    2014-01-01

    High resolution photography and spectroscopy of the martian surface (MOC, HiRISE) from orbit has revolutionized our view of Mars with one and revealed spectacular views of finely layered sedimentary materials throughout the globe [1]. Some of these sedimentary deposits are 'mound' shaped and lie inside of craters (Fig 1). Crater mound deposits are found throughout the equatorial region, as well as ice-rich deposits found in craters in the north and south polar region [2-4]. Despite their wide geographical extent and varying volatile content, the 'mound' deposits have a large number of geomorphic and structural similarities that suggest they formed via equivalent processes. Thus, modern depositional processes of ice and dust can serve as an invaluable analog for interpreting the genesis of ancient sedimentary mound deposits.

  9. Present-Day Vegetation Helps Quantifying Past Land Cover in Selected Regions of the Czech Republic

    PubMed Central

    Abraham, Vojtěch; Oušková, Veronika; Kuneš, Petr

    2014-01-01

    The REVEALS model is a tool for recalculating pollen data into vegetation abundances on a regional scale. We explored the general effect of selected parameters by performing simulations and ascertained the best model setting for the Czech Republic using the shallowest samples from 120 fossil sites and data on actual regional vegetation (60 km radius). Vegetation proportions of 17 taxa were obtained by combining the CORINE Land Cover map with forest inventories, agricultural statistics and habitat mapping data. Our simulation shows that changing the site radius for all taxa substantially affects REVEALS estimates of taxa with heavy or light pollen grains. Decreasing the site radius has a similar effect as increasing the wind speed parameter. However, adjusting the site radius to 1 m for local taxa only (even taxa with light pollen) yields lower, more correct estimates despite their high pollen signal. Increasing the background radius does not affect the estimates significantly. Our comparison of estimates with actual vegetation in seven regions shows that the most accurate relative pollen productivity estimates (PPEs) come from Central Europe and Southern Sweden. The initial simulation and pollen data yielded unrealistic estimates for Abies under the default setting of the wind speed parameter (3 m/s). We therefore propose the setting of 4 m/s, which corresponds to the spring average in most regions of the Czech Republic studied. Ad hoc adjustment of PPEs with this setting improves the match 3–4-fold. We consider these values (apart from four exceptions) to be appropriate, because they are within the ranges of standard errors, so they are related to original PPEs. Setting a 1 m radius for local taxa (Alnus, Salix, Poaceae) significantly improves the match between estimates and actual vegetation. However, further adjustments to PPEs exceed the ranges of original values, so their relevance is uncertain. PMID:24936973

  10. Present-day vegetation helps quantifying past land cover in selected regions of the Czech Republic.

    PubMed

    Abraham, Vojtěch; Oušková, Veronika; Kuneš, Petr

    2014-01-01

    The REVEALS model is a tool for recalculating pollen data into vegetation abundances on a regional scale. We explored the general effect of selected parameters by performing simulations and ascertained the best model setting for the Czech Republic using the shallowest samples from 120 fossil sites and data on actual regional vegetation (60 km radius). Vegetation proportions of 17 taxa were obtained by combining the CORINE Land Cover map with forest inventories, agricultural statistics and habitat mapping data. Our simulation shows that changing the site radius for all taxa substantially affects REVEALS estimates of taxa with heavy or light pollen grains. Decreasing the site radius has a similar effect as increasing the wind speed parameter. However, adjusting the site radius to 1 m for local taxa only (even taxa with light pollen) yields lower, more correct estimates despite their high pollen signal. Increasing the background radius does not affect the estimates significantly. Our comparison of estimates with actual vegetation in seven regions shows that the most accurate relative pollen productivity estimates (PPEs) come from Central Europe and Southern Sweden. The initial simulation and pollen data yielded unrealistic estimates for Abies under the default setting of the wind speed parameter (3 m/s). We therefore propose the setting of 4 m/s, which corresponds to the spring average in most regions of the Czech Republic studied. Ad hoc adjustment of PPEs with this setting improves the match 3-4-fold. We consider these values (apart from four exceptions) to be appropriate, because they are within the ranges of standard errors, so they are related to original PPEs. Setting a 1 m radius for local taxa (Alnus, Salix, Poaceae) significantly improves the match between estimates and actual vegetation. However, further adjustments to PPEs exceed the ranges of original values, so their relevance is uncertain. PMID:24936973

  11. Late Holocene and present-day fluvial morphodynamics in small catchment areas of Central Germany

    NASA Astrophysics Data System (ADS)

    Englhard, Michael; Damm, Bodo; Frechen, Manfred; Terhorst, Birgit

    2010-05-01

    During the past decades strong runoff events repeatedly occurred in small drainage basins of the European low mountains. In numerous events runoff was connected with erosion and transport of extensive bed load. Runoff events were predominantly triggered by rainstorms, which were limited to the catchment areas. They partly caused severe economic loss. The present study focuses on fluvial morphodynamics in northern Hesse and Lower Saxony. In this area runoff and transport of bed load occurred in small tributary catchment areas of the Fulda, Werra and Oberweser rivers. In general, the small drainage basins are used by agriculture and forestry. Drainage channels are developed as gullies and are incised into solid bedrock, Quaternary hillslope sediments, alluvial fills, and anthropogenic deposits. Vertical incision into the bedrock may amount to 1 meter per event. Furthermore, in single cases sediment discharge amounted to 16.000 m³ in addition to the suspension load. On the base of historical analyses about 50 severe runoff events with a maximum frequency of 10 events during 1965 are recorded during the past 150 years in the study area. Field survey, sedimentological analyses and dating reveal intensive runoff processes since the Neolithic age in a comparable catchment area. In this context potsherds could be dated to the Linear Pottery culture, which were detected in an alluvial cone of the "Rehgraben gully", close to the city of.Kassel. Furthermore, findings of fossil wood were recovered in the same alluvial cone. Radiocarbon dating reveals calibrated ages which are for the most parts younger than AD. In younger sediments we suppose the severe runoff event of 1342. Current studies in the catchment area of the Rehgraben aim to distinguish different processes of the fluvial morphodynamics on a temporal scale and to estimate potential Holocene erosional rates. References Damm, B., 2004. Geschiebe führende und murfähige Wildbäche in Mittelgebirgsr

  12. Present-day crustal motion along the Longitudinal Valley Fault, eastern Taiwan

    NASA Astrophysics Data System (ADS)

    Yu, Shui-Beih; Kuo, Long-Chen

    2001-04-01

    The NNE-striking Longitudinal Valley Fault (LVF) in eastern Taiwan is an extremely active high-angle thrust fault. It bounds the Coastal Range and the Longitudinal Valley, which is considered a collision boundary between the Philippine Sea and the Eurasian plates. Repeated GPS data in the Longitudinal Valley area from 1992 to 1999 are utilized to study the spatial variation of crustal motion along the LVF. With respect to Penghu in the Chinese continental margin, velocities for stations on the western side of the LVF (Longitudinal Valley and eastern Central Range) are 18-35 mm/yr in directions 283-311°, whereas those on the eastern side of the LVF, the Coastal Range, are 28-68 mm/yr in directions 303-324°. A major discontinuity of about 30 mm/yr on the rate of crustal motion across the Longitudinal Valley is attributed to the aseismic slip along the LVF as revealed by trilateration data previously. To the south of Fengping, the block motions of the Coastal Range are 31-40 mm/yr in 317-330° relative to the Central Range, while the near-fault motions are 13-33 mm/yr in 309-336°. Various partitions on the left-lateral strike-slip and convergent components along the LVF are found. In the southern Longitudinal Valley crustal motion is mainly accommodated on the LVF and the Luyeh Fault. In contrast, those in the central and northern Longitudinal Valley are partly taken up on the faults to the east of the LVF or result in the elastic deformation of the Coastal Range. The crustal motion in the northern Longitudinal Valley area is likely to be distributed in the several NE-striking thrusts in a horsetail pattern and obliquely cut the northern Coastal Range, with a small portion of fault-slips along the LVF. Data from dense-deployed GPS networks across the LVF can be employed to give better estimates of near-fault motions and delineate the surface traces of the LVF. Repeated GPS and leveling data from two stations on both ends of the Yuli Bridge that are 575 m apart

  13. Lyman Alpha-emitting Galaxies at z = 2.1: Characterizing the Progenitors of Typical Present-day Galaxies

    NASA Astrophysics Data System (ADS)

    Gawiser, Eric J.; Guaita, L.; Padilla, N.; Francke, H.; Bond, N. A.; Gronwall, C.; Ciardullo, R.; Sinawa, S.; Feldmeier, J. J.; MUSYC Collaboration

    2010-01-01

    We discovered a sample of 261 Lyman alpha emitting (LAE) galaxies at z=2.1 in an ultra-deep 3727A narrow-band MUSYC image of the Extended Chandra Deep Field-South. LAEs were selected to have rest-frame equivalent widths >20A and emission line fluxes >3.7x10-17 ergs/cm2/s, corresponding to L_Lya>1.2x1042 ergs/s. 3% of the original candidates were detected in X-rays by Chandra, and 7% were detected in the rest-frame far-UV by GALEX; these objects were eliminated to minimize contamination by AGN and low-redshift galaxies. Our sample has median rest-frame EW=40A, and only a few galaxies have rest-frame EW bigger than 200A. Our results show that the luminosity function of LAEs at z=2.1 is consistent with that of LAEs at z=3.1 but with number density a factor of 1.8+-0.3 higher. We used the rest frame UV luminosity to estimate a median star formation rate of 4 Msun/yr. Clustering analysis reveals that LAEs at z=2.1 have r0=3+-0.5 Mpc, corresponding to b=1.0+-0.2, the lowest clustering bias of any high-redshift galaxy population. This implies that z=2.1 LAEs reside in dark matter halos with masses 1010 Msun, which are the lowest-mass halos yet probed at this redshift. We used the Sheth-Tormen conditional mass function to study the descendants of these LAEs and found that their typical present-day descendants are local galaxies with sub-L* and L* luminosities, like the Milky Way. We gratefully acknowledge grant support for this research from NSF, DOE, and NASA.

  14. Present-day crustal deformation along the Magallanes-Fagnano Fault System in Tierra del Fuego from repeated GPS observations

    NASA Astrophysics Data System (ADS)

    Mendoza, L.; Perdomo, R.; Hormaechea, J. L.; Del Cogliano, D.; Fritsche, M.; Richter, A.; Dietrich, R.

    2011-03-01

    The present-day deformation of the earth crust in the Argentine part of Tierra del Fuego main island (southernmost South America) is here investigated based on repeated geodetic GPS observations. The island is traversed by the active transform boundary between the South American and Scotia tectonic plates, represented by the Magallanes-Fagnano fault system. Since 1993 a regional network comprising to date 29 GPS sites has been observed almost every year. The complete set of accumulated observations was processed using the Bernese GPS software and state-of-the-art processing strategies and models. The utilization of homogeneous GPS products resulting from a reprocessing of the global IGS network warrants a stable realization of a global reference frame. For each GPS site 3-D positions and linear velocities with error estimates were obtained. A strain analysis of the horizontal velocity components revealed the zones of major deformation activity. A 30-km-wide deformation belt centred on the main trace of the fault system was identified. This belt is bordered to the north (South America) and south (Scotia) by geodynamically stable zones, which move horizontally with a relative average velocity of 4.4 ± 0.6 (east) and -0.3 ± 0.4 (north) mm a-1. Within the deformation belt a maximum strain rate in the order of 0.25 μstrain per year has been detected. A pronounced change in the deformation style from transtension (east) to transpression (west) is observed. The area of predominating shortening of the crust coincides with a local rotation minimum and relative uplift. Throughout the period covered by the GPS observations the displacements and deformations occurred to be linear with time.

  15. Mantle-circulation models with sequential data assimilation: inferring present-day mantle structure from plate-motion histories.

    PubMed

    Bunge, Hans-Peter; Richards, M A; Baumgardner, J R

    2002-11-15

    limited in age to the Cretaceous. This result implies that sequential assimilation of past plate-motion models is ineffective in studying the temporal evolution of core-mantle-boundary heterogeneity, and that a method for extrapolating present-day information backwards in time is required. For short time periods (of the order of perhaps a few tens of Myr) such a method exists in the form of crude 'backward' convection calculations. For longer time periods (of the order of a mantle overturn), a rigorous approach to extrapolating information back in time exists in the form of iterative nonlinear optimization methods that carry assimilated information into the past through the use of an adjoint mantle convection model. PMID:12460480

  16. Evolution of the stress field in the southern Scotia Arc from the late Mesozoic to the present-day

    NASA Astrophysics Data System (ADS)

    Maestro, Adolfo; López-Martínez, Jerónimo; Galindo-Zaldívar, Jesús; Bohoyo, Fernando; Mink, Sandra

    2014-12-01

    The geological evolution of the Scotia Arc, which developed between Antarctica and South America, has facilitated the connection between the Pacific and Atlantic oceans and, has important global implications. To improve the knowledge of the late Mesozoic evolution of the southern Scotia Arc, over 6000 brittle mesostructures were measured over the last 20 years at different outcrops from the northern Antarctic Peninsula and the South Shetland Islands as well as the James Ross and South Orkney archipelagos. This dataset covers a length of more than 1000 km of the arc. Fault data were analysed using the Etchecopar, y-R, Right Dihedra, Stress Inversion and Search Grid Inversion Palaeostress Determination methods. A total of 275 stress tensors were obtained. The results showed that the maximum horizontal stress was in the ENE-WSW and the NW-SE orientations and that the horizontal extension tensors were oriented NE-SW and NW-SE. In addition, seismic activity and focal mechanism solutions were analysed using the Gephart method to establish the present-day stress field and characterise the active tectonics. The results obtained suggest that there is a regional NE-SW compression and a NW-SE extension regime at the present day. The Southern Scotia Arc has a complex geological history due to the different tectonic settings (transform, convergent and divergent) that have affected this sector during its geological evolution from the late Mesozoic until the present day. Six stress fields were obtained from the brittle mesostructure population analysis in the region. The NW-SE and N-S maximum horizontal stresses were related to a combination of Mesozoic oceanic subduction of the former Phoenix Plate under the Pacific margin of the Antarctic Plate, Mesozoic-Cenozoic subduction of the northern Weddell Sea and the Oligocene to the Middle Miocene dextral strike-slip movement between the Scotia and Antarctic plates along the South Scotia Ridge. The NE-SW compression was related to

  17. Very high resolution modelling of the Surface Mass Balance of the Greenland Ice Sheet: Present day conditions and future prospects.

    NASA Astrophysics Data System (ADS)

    Mottram, Ruth; Aðalgeirsdóttir, Guðfinna; Boberg, Fredrik; Hesselbjerg Christensen, Jens; Bøssing Christensen, Ole; Langen, Peter; Rodehacke, Christian; Stendel, Martin; Yang, Shuting

    2014-05-01

    Recent experiments with the Regional Climate Model (RCM) HIRHAM5 have produced new surface mass balance (SMB) estimates at the unprecedented high horizontal resolution of 0.05 degrees (~5.5km). These simulations indicate a present day SMB of 347 ± 98 Gt/year over the whole ice sheet averaged over the period 1989 - 2012 driven by the ERA-Interim reanalysis dataset. We validate accumulation rates over the ice sheet using estimates from shallow firn cores to confirm the importance of resolution to accurate estimates of accumulation. Comparison with PROMICE and GC-Net automatic weather station observations shows the model represents present day climate and climate variability well when driven by the ERA-Interim reanalysis dataset. Comparison with a simulation at 0.25 degrees (~27km) resolution from the same model shows a significantly different calculated SMB over the whole ice sheet, largely due to changes in precipitation distribution over Greenland. The very high resolution requires a more sophisticated treatment of sub-grid scale processes in the snow pack including meltwater retention and refreezing and an enhanced albedo scheme. Our results indicate retention processes account for a significant proportion of the total surface budget based on a new parameterization scheme in the model. SMB projections, driven by the EC-Earth Global Climate Model (GCM) at the boundaries for the RCP 4.5 scenario indicate a declining surface mass balance over the 21st century with some compensation for warmer summer temperatures and enhanced melt in the form of increased precipitation. A cold bias in the driving GCM for present day conditions suggests that this simulation likely underestimates the change in SMB. However, the downscaled precipitation fields compare well with those in the reanalysis driven simulations. A soon-to-be complete simulation uses driving fields from the GCM running the RCP8.5 scenario.

  18. Past agricultural land use and present-day fire regimes can interact to determine the nature of seed predation.

    PubMed

    Stuhler, John D; Orrock, John L

    2016-06-01

    Historical agriculture and present-day fire regimes can have significant effects on contemporary ecosystems. Although past agricultural land use can lead to long-term changes in plant communities, it remains unclear whether these persistent land-use legacies alter plant-consumer interactions, such as seed predation, and whether contemporary disturbance (e.g., fire) alters the effects of historical agriculture on these interactions. We conducted a study at 27 sites distributed across 80,300 ha in post-agricultural and non-agricultural longleaf pine woodlands with different degrees of fire frequency to test the hypothesis that past and present-day disturbances that alter plant communities can subsequently alter seed predation. We quantified seed removal by arthropods and rodents for Tephrosia virginiana and Vernonia angustifolia, species of conservation interest. We found that the effects of land-use history and fire frequency on seed removal were contingent on granivore guild and microhabitat characteristics. Tephrosia virginiana removal was greater in low fire frequency sites, due to greater seed removal by rodents. Although overall removal of V. angustifolia did not differ among habitats, rodents removed more seeds than arthropods at post-agricultural sites and non-agricultural sites with low fire frequencies, but not at non-agricultural sites with high fire frequencies. Land-use history and fire frequency also affected the relationship between microhabitat characteristics and removal of V. angustifolia. Our results suggest that historical agriculture and present-day fire regimes may alter seed predation by shifting the impact of rodent and arthropod seed predators among habitats, with potential consequences for the establishment of rare plant species consumed by one or both predators. PMID:26905418

  19. The present-day strain partitioning of the Western Alps and its relationships with the crustal scale geometry

    NASA Astrophysics Data System (ADS)

    Schwartz, S.; Lardeaux, J. M.; Tricart, P.; Paul, A.; Béthoux, N.; Masson, F.

    2003-04-01

    In the orogenic belt, the combination of the geological data (tectonic, petrologic and kinematic analysis) with the geophysical imagery of the crust (regional seismicity, local earthquake tomography and gravimetry) allows to obtain crustal scale models coherent with the present-day deformation. In this way, the recent pluridisciplinary studies performed in the framework of " Geo-France 3D Alpes " show an important syn-convergence strain-partitioning at the scale of the western alpine belt. In the internal domain, this strain-partitioning, corresponds to extensional tectonics combinated with important strike-slip components while the external domain and the Po plain, located at the periphery, record an important shortening accomodated in surface by thrust and strike-slip faults. In order to understand the alpine present-day strain pattern, we propose and discuss a new crustal-scale cross-section performed along the Pelvoux-Dora Maira transect. The proeminent features of this crustal-scale geometry are : -the existence of a slice of cold and rigid mantle of Apulian origin beneath the Dora Maira massif. This rigid mantle is truncated in two distinct bodies by a system of deeply-rooted vertical faults related to the Insubric line. -these two main bodies of mantle acted as indenters driving the decoupling of the European crust and at least a part of the exhumation of the high-pressure metamorphic units. -the deep architecture is characterized by the stacking of crustal slices detached from the European lithosphere. Some of these slices represent tectonic extrusions within the overlying Piemont Schistes lustrés. -the Monviso eclogitized ophiolites are plunging up to 20 km depth below the Piemont schistes lustrés. In this geometrical model, the decoupling of the mantle identor drives the crustal-scale strain-partitioning of the western Alps. Indeed, the lower part of the rigid mantle transfers the compression onto the european foreland and is responsible for the present-day

  20. Iceland hotspot track in southeast Greenland causes huge present-day vertical viscoelastic motion of the bedrock

    NASA Astrophysics Data System (ADS)

    Khan, Shfaqat Abbas; Sasgen, Ingo; Bevis, Michael; van Dam, Tonie; Wahr, John; Bamber, Jonathan; Wouters, Bert; Helm, Veit; Willis, Michael; Csatho, Beata; Knudsen, Per; Kuipers Munneke, Peter; Kjær, Kurt

    2016-04-01

    The process of Glacial Isostatic Adjustment (GIA) represents the ongoing response of the solid Earth to past ice mass loss that occurred following the Last Glacial Maximum (LGM, ~21 ka B.P.). The magnitude of the GIA uplift depends on the temporal history of the ice load and is highly sensitive to variations in upper mantle viscosity. Greenland GIA is thought to be well contained and due to relative high viscosity, influence of more recent changes e.g. since the Little Ice Age have minor present-day effect (<2 mm/yr). Here we use data from the Greenland Global Positioning System (GPS) network to measure GIA. We identify an unexpected GIA anomaly of ~12 mm/yr in southeast Greenland, which we interpret as linked to a zone of warmer upper mantle caused by the Iceland hotspot track that would reduce the viscosity and produce greater viscoelastic uplift due to recent ice mass changes. We reconsider the evolution of the Greenland ice sheet since LGM and estimate a total ice mass loss equivalent to sea level rise of 4.9 m since LGM. Our observations suggest southeast and northwest Greenland, subject to present-day major ice loss, also contributed by significantly more mass loss on millennia scale than previously estimated.

  1. Isolation and prominent aboriginal maternal legacy in the present-day population of La Gomera (Canary Islands).

    PubMed

    Fregel, Rosa; Cabrera, Vicente M; Larruga, José M; Hernández, Juan C; Gámez, Alejandro; Pestano, Jose J; Arnay, Matilde; González, Ana M

    2015-09-01

    The present-day population structure of La Gomera is outstanding in its high aboriginal heritage, the greatest in the Canary Islands. This was earlier confirmed by both mitochondrial DNA and autosomal analyses, although genetic drift due to the fifteenth century European colonization could not be excluded as the main factor responsible. The present mtDNA study of aboriginal remains and extant samples from the six municipal districts of the island indeed demonstrates that the pre-Hispanic colonization of La Gomera by North African people involved a strong founder event, shown by the high frequency of the indigenous Canarian U6b1a lineage in the aboriginal samples (65%). This value is even greater than that observed in the extant population (44%), which in turn is the highest of all the seven Canary Islands. In contrast to previous results obtained for the aboriginal populations of Tenerife and La Palma, haplogroups related to secondary waves of migration were not detected in La Gomera aborigines, indicating that isolation also had an important role in shaping the current population. The rugged relief of La Gomera divided into several distinct valleys probably promoted subsequent aboriginal intra-insular differentiation that has continued after the European colonization, as seen in the present-day population structure observed on the island. PMID:25407001

  2. Present-day and future Antarctic ice sheet climate and surface mass balance in the Community Earth System Model

    NASA Astrophysics Data System (ADS)

    Lenaerts, Jan T. M.; Vizcaino, Miren; Fyke, Jeremy; van Kampenhout, Leo; van den Broeke, Michiel R.

    2016-02-01

    We present climate and surface mass balance (SMB) of the Antarctic ice sheet (AIS) as simulated by the global, coupled ocean-atmosphere-land Community Earth System Model (CESM) with a horizontal resolution of ˜1° in the past, present and future (1850-2100). CESM correctly simulates present-day Antarctic sea ice extent, large-scale atmospheric circulation and near-surface climate, but fails to simulate the recent expansion of Antarctic sea ice. The present-day Antarctic ice sheet SMB equals 2280 ± 131 {Gt year^{-1}} , which concurs with existing independent estimates of AIS SMB. When forced by two CMIP5 climate change scenarios (high mitigation scenario RCP2.6 and high-emission scenario RCP8.5), CESM projects an increase of Antarctic ice sheet SMB of about 70 {Gt year^{-1}} per degree warming. This increase is driven by enhanced snowfall, which is partially counteracted by more surface melt and runoff along the ice sheet's edges. This intensifying hydrological cycle is predominantly driven by atmospheric warming, which increases (1) the moisture-carrying capacity of the atmosphere, (2) oceanic source region evaporation, and (3) summer AIS cloud liquid water content.

  3. Isolation and prominent aboriginal maternal legacy in the present-day population of La Gomera (Canary Islands)

    PubMed Central

    Fregel, Rosa; Cabrera, Vicente M; Larruga, José M; Hernández, Juan C; Gámez, Alejandro; Pestano, Jose J; Arnay, Matilde; González, Ana M

    2015-01-01

    The present-day population structure of La Gomera is outstanding in its high aboriginal heritage, the greatest in the Canary Islands. This was earlier confirmed by both mitochondrial DNA and autosomal analyses, although genetic drift due to the fifteenth century European colonization could not be excluded as the main factor responsible. The present mtDNA study of aboriginal remains and extant samples from the six municipal districts of the island indeed demonstrates that the pre-Hispanic colonization of La Gomera by North African people involved a strong founder event, shown by the high frequency of the indigenous Canarian U6b1a lineage in the aboriginal samples (65%). This value is even greater than that observed in the extant population (44%), which in turn is the highest of all the seven Canary Islands. In contrast to previous results obtained for the aboriginal populations of Tenerife and La Palma, haplogroups related to secondary waves of migration were not detected in La Gomera aborigines, indicating that isolation also had an important role in shaping the current population. The rugged relief of La Gomera divided into several distinct valleys probably promoted subsequent aboriginal intra-insular differentiation that has continued after the European colonization, as seen in the present-day population structure observed on the island. PMID:25407001

  4. Unraveling the geochemistry of melts in exhumed mantle domains in present-day and fossil magma-poor rifted margins

    NASA Astrophysics Data System (ADS)

    Amann, Méderic; Ulrich, Marc; Autin, Julia; Manatschal, Gianreto; Epin, Marie-Eva; Müntener, Othmar; Boiron, Marie-Christine; Sauter, Daniel

    2016-04-01

    The role of magmatic processes occurring during the continental break-up and the onset of steady-state seafloor spreading are still a matter of debate. Beside the tectonic processes like stretching, thinning and exhumation, magmatic processes also play a key role in the evolution and breakup of magma-poor rifted margins. To unravel the impact of such processes, Ocean-Continent-Transitions (OCTs) are of particular interest. OCTs are complex areas where hyper-extended continental crust, exhumed mantle and proto-oceanic crust occur. All these domains have been identified and sampled in both present-day (Iberia/Newfoundland margins) and fossil margins (Platta/Err nappes). In this study, we present preliminary results that enable to characterize the nature of the mantle rocks and the melts found in the OCTs of these paleo- and present-day margins with the aim to investigate how the mantle evolves from initial exhumation to final lithospheric breaks. In OCTs two types of mantle rocks can be observed: (i) a « sub-continental type » free of syn-exhumation melt imprint preserving the early geochemical evolution, and (ii) a « refertilized type » characterized by melt infiltration and mantle-melt interaction. Melts from these domains have different major, trace element and isotopic compositions and can therefore be used to constrain how melt interacts with the mantle and to understand the role of magmatic processes in the break-up. We therefore summarized whole-rock, in-situ and isotopic analysis available in the literature from the Iberia/Newfoundland present-day margin system and completed the existing database with new additional data from the Iberia margin. These new data have been obtained using in-situ technics mainly on clinopyroxenites, serpentinized peridotites and gabbros of ODP drill cores. Around 200 new data have been acquired using the LA-ICPMS technic. Preliminary results show that clinopyroxenes in serpentinized peridodite breccia from ODP site 637A and

  5. Simple models for late Holocene and present-day Patagonian glacier fluctuations and predictions of a geodetically detectable isostatic response

    NASA Astrophysics Data System (ADS)

    Ivins, Erik R.; James, Thomas S.

    1999-09-01

    The late Holocene glacial moraine chronology in the southernmost South American Andes includes four ^1 ^4 C dated Neoglacial advances and retreats. These are used as proxy information to characterize mass fluctuation of the Patagonian icefields during the last 5000 years. Modelled ice loads force a phase-lagged viscoelastic gravitational deformation of the solid Earth. The ancient glacier fluctuations may, therefore, drive present-day crustal motion even in the absence of present-day ice mass imbalance. Numerical models show that such rates of present-day uplift and subsidence are larger than those driven by the viscous memory of late Pleistocene deglaciation. Both spherical and flat-earth models are employed, the latter being used to study exhaustively the effects of glacial load history on the predicted vertical crustal velocity. Recent assessment of net mass balance from 1944 to 1985 indicates that the Southern Patagonian icefield has significantly deteriorated due to snout retreat and thinning. Volume loss rates are estimated at about 3.4-9.3 km^3 yr^- ^1 . The predicted vertical isostatic response to this recession and to the modelled Holocene Neoglaciations is at a marginally detectable level (~1 mm yr^- ^1 ) if the mantle/asthenosphere beneath Patagonia has a viscosity of about 10^2 ^1 Pa s. However, for reduced mantle viscosities, the younger Holocene glacial load histories predict larger signatures. In fact, if the viscosity is about 2x10^2 ^0 Pa s, or lower, then geodetically detectable vertical motion may be driven by a regional Little Ice Age (LIA) (1400-1750 AD) glacier advance and subsequent 20th century retreat. Although this value for mantle viscosity is lower than thought typical of continental shield mantle (~10^2 ^1 Pa s), it is consistent with inversions for post-seismic relaxation time constants in island arc environments and in regions with significant Neogene continental tectonism. In the viscosity regime of 5x10^1 ^8 -2x10^1 ^9 Pa s, the

  6. Oxidation of dissolved iron under warmer, wetter conditions on Mars: Transitions to present-day arid environments

    NASA Technical Reports Server (NTRS)

    Burns, R. G.

    1993-01-01

    The copious deposits of ferric-iron assemblages littering the surface of bright regions of Mars indicate that efficient oxidative weathering reactions have taken place during the evolution of the planet. Because the kinetics of atmosphere-surface (gas-solid) reactions are considerably slower than chemical weathering reactions involving an aqueous medium, most of the oxidation products now present in the martian regolith probably formed when groundwater flowed near the surface. This paper examines how chemical weathering reactions were effected by climatic variations when warm, wet environments became arid on Mars. Analogies are drawn with hydrogeochemical and weathering environments on the Australian continent where present-day oxidation of iron is occurring in acidic ground water under arid conditions.

  7. HLA Class I and Class II Alleles and Haplotypes Confirm the Berber Origin of the Present Day Tunisian Population.

    PubMed

    Hajjej, Abdelhafidh; Almawi, Wassim Y; Hattab, Lasmar; El-Gaaied, Amel; Hmida, Slama

    2015-01-01

    In view of its distinct geographical location and relatively small area, Tunisia witnessed the presence of many civilizations and ethnic groups throughout history, thereby questioning the origin of present-day Tunisian population. We investigated HLA class I and class II gene profiles in Tunisians, and compared this profile with those of Mediterranean and Sub-Sahara African populations. A total of 376 unrelated Tunisian individuals of both genders were genotyped for HLA class I (A, B) and class II (DRB1, DQB1), using reverse dot-blot hybridization (PCR-SSO) method. Statistical analysis was performed using Arlequin software. Phylogenetic trees were constructed by DISPAN software, and correspondence analysis was carried out by VISTA software. One hundred fifty-three HLA alleles were identified in the studied sample, which comprised 41, 50, 40 and 22 alleles at HLA-A,-B,-DRB1 and -DQB1 loci, respectively. The most frequent alleles were HLA-A*02:01 (16.76%), HLA-B*44:02/03 (17.82%), HLA-DRB1*07:01 (19.02%), and HLA-DQB1*03:01 (17.95%). Four-locus haplotype analysis identified HLA-A*02:01-B*50:01-DRB1*07:01-DQB1*02:02 (2.2%) as the common haplotype in Tunisians. Compared to other nearby populations, Tunisians appear to be genetically related to Western Mediterranean population, in particular North Africans and Berbers. In conclusion, HLA genotype results indicate that Tunisians are related to present-day North Africans, Berbers and to Iberians, but not to Eastern Arabs (Palestinians, Jordanians and Lebanese). This suggests that the genetic contribution of Arab invasion of 7th-11th century A.D. had little impact of the North African gene pool. PMID:26317228

  8. Present-day oxidative subsidence of organic soils and mitigation in the Sacramento-San Joaquin Delta, California, USA

    NASA Astrophysics Data System (ADS)

    Deverel, Steven J.; Ingrum, Timothy; Leighton, David

    2016-05-01

    Subsidence of organic soils in the Sacramento-San Joaquin Delta threatens sustainability of the California (USA) water supply system and agriculture. Land-surface elevation data were collected to assess present-day subsidence rates and evaluate rice as a land use for subsidence mitigation. To depict Delta-wide present-day rates of subsidence, the previously developed SUBCALC model was refined and calibrated using recent data for CO2 emissions and land-surface elevation changes measured at extensometers. Land-surface elevation change data were evaluated relative to indirect estimates of subsidence and accretion using carbon and nitrogen flux data for rice cultivation. Extensometer and leveling data demonstrate seasonal variations in land-surface elevations associated with groundwater-level fluctuations and inelastic subsidence rates of 0.5-0.8 cm yr-1. Calibration of the SUBCALC model indicated accuracy of ±0.10 cm yr-1 where depth to groundwater, soil organic matter content and temperature are known. Regional estimates of subsidence range from <0.3 to >1.8 cm yr-1. The primary uncertainty is the distribution of soil organic matter content which results in spatial averaging in the mapping of subsidence rates. Analysis of leveling and extensometer data in rice fields resulted in an estimated accretion rate of 0.02-0.8 cm yr-1. These values generally agreed with indirect estimates based on carbon fluxes and nitrogen mineralization, thus preliminarily demonstrating that rice will stop or greatly reduce subsidence. Areas below elevations of -2 m are candidate areas for implementation of mitigation measures such as rice because there is active subsidence occurring at rates greater than 0.4 cm yr-1.

  9. A High-resolution 3D Geodynamical Model of the Present-day India-Asia Collision System

    NASA Astrophysics Data System (ADS)

    Kaus, B.; Baumann, T.

    2015-12-01

    We present a high-resolution, 3D geodynamic model of the present-day India-Asia collision system. The model is separated into multiple tectonic blocks, for which we estimate the first order rheological properties and the impact on the dynamics of the collision system. This is done by performing systematic simulations with different rheologies to minimize the misfit to observational constraints such as the GPS-velocity field. The simulations are performed with the parallel staggered grid FD code LaMEM using a numerical resolution of at least 512x512x256 cells to resolve dynamically important shear zones reasonably well. A fundamental part of this study is the reconstruction of the 3D present-day geometry of Tibet and the adjacent regions. Our interpretations of crust and mantle lithosphere geometry are jointly based on a globally available shear wave tomography (Schaeffer and Lebedev, 2013) and the Crust 1.0 model (Laske et al. http://igppweb.ucsd.edu/~gabi/crust1.html). We regionally refined and modified our interpretations based on seismicity distributions and focal mechanisms and incorporated regional receiver function studies to improve the accuracy of the Moho in particular. Results suggest that we can identify at least one "best-fit" solution in terms of rheological model properties that reproduces the observed velocity field reasonably well, including the strong rotation of the GPS velocity around the eastern syntax of the Himalaya. We also present model co-variances to illustrate the trade-offs between the rheological model parameters, their respective uncertainties, and the model fit. Schaeffer, A.J., Lebedev, S., 2013. Global shear speed structure of the upper mantle and transition zone. Geophysical Journal International 194, 417-449. doi:10.1093/gji/ggt095

  10. Similarities in the Spatial Pattern of the Surface Flux Response to Present-Day Greenhouse Gases and Aerosols

    NASA Astrophysics Data System (ADS)

    Persad, G.; Ming, Y.; Ramaswamy, V.

    2014-12-01

    Recent studies suggest that present-day greenhouse gases (GHGs) and aerosols can produce remarkably similar patterns of climate response in fully coupled general circulation model (GCM) simulations, despite having significantly different spatial patterns of top-of-atmosphere (TOA) forcing. However, there is little understanding of the mechanisms of ocean-atmosphere interaction that could lead to the response pattern formation. Surface flux perturbations are a crucial pathway by which TOA forcing is communicated to the ocean, and may be a vital link in explaining the spatial similarities in the fully coupled responses to disparate TOA forcing patterns—a phenomenon with implications for detection and attribution, as well as the climate sensitivity to different forcers. We analyze the surface energy budget response to present-day aerosols versus GHGs in single forcing, fixed SST, atmospheric GCM experiments to identify mechanisms for response pattern formation via surface flux perturbations. We find that, although the TOA forcing spatial patterns of GHGs and aerosols are largely uncorrelated, their surface radiative and heat flux patterns are significantly anti-correlated. Furthermore, this anti-correlation is largely explained by similar (but sign-reversed) spatial patterns of surface latent and sensible heat flux response to the two forcers, particularly over the winter-hemisphere extratropical oceans. These are, in turn, driven by spatially similar perturbations in surface winds from changes in mean tropical and midlatitude circulation. These results suggest that the mean atmospheric circulation, which has many anti-symmetric responses to GHG and aerosol forcings, is an efficient homogenizer of spatial patterns in the surface heat flux response to heterogeneous TOA forcings, creating an atmosphere-only pathway for similarities in the fully coupled response.

  11. Present-day oxidative subsidence of organic soils and mitigation in the Sacramento-San Joaquin Delta, California, USA

    NASA Astrophysics Data System (ADS)

    Deverel, Steven J.; Ingrum, Timothy; Leighton, David

    2016-03-01

    Subsidence of organic soils in the Sacramento-San Joaquin Delta threatens sustainability of the California (USA) water supply system and agriculture. Land-surface elevation data were collected to assess present-day subsidence rates and evaluate rice as a land use for subsidence mitigation. To depict Delta-wide present-day rates of subsidence, the previously developed SUBCALC model was refined and calibrated using recent data for CO2 emissions and land-surface elevation changes measured at extensometers. Land-surface elevation change data were evaluated relative to indirect estimates of subsidence and accretion using carbon and nitrogen flux data for rice cultivation. Extensometer and leveling data demonstrate seasonal variations in land-surface elevations associated with groundwater-level fluctuations and inelastic subsidence rates of 0.5-0.8 cm yr-1. Calibration of the SUBCALC model indicated accuracy of ±0.10 cm yr-1 where depth to groundwater, soil organic matter content and temperature are known. Regional estimates of subsidence range from <0.3 to >1.8 cm yr-1. The primary uncertainty is the distribution of soil organic matter content which results in spatial averaging in the mapping of subsidence rates. Analysis of leveling and extensometer data in rice fields resulted in an estimated accretion rate of 0.02-0.8 cm yr-1. These values generally agreed with indirect estimates based on carbon fluxes and nitrogen mineralization, thus preliminarily demonstrating that rice will stop or greatly reduce subsidence. Areas below elevations of -2 m are candidate areas for implementation of mitigation measures such as rice because there is active subsidence occurring at rates greater than 0.4 cm yr-1.

  12. HLA Class I and Class II Alleles and Haplotypes Confirm the Berber Origin of the Present Day Tunisian Population

    PubMed Central

    Hajjej, Abdelhafidh; Almawi, Wassim Y.; Hattab, Lasmar; El-Gaaied, Amel; Hmida, Slama

    2015-01-01

    In view of its distinct geographical location and relatively small area, Tunisia witnessed the presence of many civilizations and ethnic groups throughout history, thereby questioning the origin of present-day Tunisian population. We investigated HLA class I and class II gene profiles in Tunisians, and compared this profile with those of Mediterranean and Sub-Sahara African populations. A total of 376 unrelated Tunisian individuals of both genders were genotyped for HLA class I (A, B) and class II (DRB1, DQB1), using reverse dot-blot hybridization (PCR-SSO) method. Statistical analysis was performed using Arlequin software. Phylogenetic trees were constructed by DISPAN software, and correspondence analysis was carried out by VISTA software. One hundred fifty-three HLA alleles were identified in the studied sample, which comprised 41, 50, 40 and 22 alleles at HLA-A,-B,-DRB1 and -DQB1 loci, respectively. The most frequent alleles were HLA-A*02:01 (16.76%), HLA-B*44:02/03 (17.82%), HLA-DRB1*07:01 (19.02%), and HLA-DQB1*03:01 (17.95%). Four-locus haplotype analysis identified HLA-A*02:01-B*50:01-DRB1*07:01-DQB1*02:02 (2.2%) as the common haplotype in Tunisians. Compared to other nearby populations, Tunisians appear to be genetically related to Western Mediterranean population, in particular North Africans and Berbers. In conclusion, HLA genotype results indicate that Tunisians are related to present-day North Africans, Berbers and to Iberians, but not to Eastern Arabs (Palestinians, Jordanians and Lebanese). This suggests that the genetic contribution of Arab invasion of 7th-11th century A.D. had little impact of the North African gene pool. PMID:26317228

  13. Complex Bedforms and Complex Water Masses: A Case Study from the Tertiary to Present-day, Pelotas Basin, Offshore Uruguay

    NASA Astrophysics Data System (ADS)

    Thompson, P.; Badalini, G.; Wrigley, S.; Walker, R.; Argent, J.; Hernandez-Molina, J.; de Santa Ana, H.; Soto, M.; Tomasini, J.

    2015-12-01

    varied both spatially and temporally and operated at various water depths. This complexity continues Present-day and is spectacularly imaged by pseudo time-lapse seismic data from the Present-day water column. These data, which are commonly neglected, highlight the true complexity of ocean currents and show how discrete dynamic water masses mix and move over time.

  14. Estimating present day extreme water level exceedance probabilities around the coastline of Australia: tropical cyclone-induced storm surges

    NASA Astrophysics Data System (ADS)

    Haigh, Ivan D.; MacPherson, Leigh R.; Mason, Matthew S.; Wijeratne, E. M. S.; Pattiaratchi, Charitha B.; Crompton, Ryan P.; George, Steve

    2014-01-01

    The incidence of major storm surges in the last decade have dramatically emphasized the immense destructive capabilities of extreme water level events, particularly when driven by severe tropical cyclones. Given this risk, it is vitally important that the exceedance probabilities of extreme water levels are accurately evaluated to inform risk-based flood and erosion management, engineering and for future land-use planning and to ensure the risk of catastrophic structural failures due to under-design or expensive wastes due to over-design are minimised. Australia has a long history of coastal flooding from tropical cyclones. Using a novel integration of two modeling techniques, this paper provides the first estimates of present day extreme water level exceedance probabilities around the whole coastline of Australia, and the first estimates that combine the influence of astronomical tides, storm surges generated by both extra-tropical and tropical cyclones, and seasonal and inter-annual variations in mean sea level. Initially, an analysis of tide gauge records has been used to assess the characteristics of tropical cyclone-induced surges around Australia. However, given the dearth (temporal and spatial) of information around much of the coastline, and therefore the inability of these gauge records to adequately describe the regional climatology, an observationally based stochastic tropical cyclone model has been developed to synthetically extend the tropical cyclone record to 10,000 years. Wind and pressure fields derived for these synthetically generated events have then been used to drive a hydrodynamic model of the Australian continental shelf region with annual maximum water levels extracted to estimate exceedance probabilities around the coastline. To validate this methodology, selected historic storm surge events have been simulated and resultant storm surges compared with gauge records. Tropical cyclone induced exceedance probabilities have been combined with

  15. Volcanoes and the environment: Lessons for understanding Earth's past and future from studies of present-day volcanic emissions

    NASA Astrophysics Data System (ADS)

    Mather, Tamsin A.

    2015-10-01

    Volcanism has affected the environment of our planet over a broad range of spatial (local to global) and temporal (< 1 yr to 100s Myr) scales and will continue to do so. As well as examining the Earth's geological record and using computer modelling to understand these effects, much of our knowledge of these processes comes from studying volcanism on the present-day planet. Understanding the full spectrum of possible routes and mechanisms by which volcanism can affect the environment is key to developing a realistic appreciation of possible past and potential future volcanic impact scenarios. This review paper seeks to give a synoptic overview of these potential mechanisms, focussing on those that we can seek to understand over human timescales by studying current volcanic activity. These effects are wide ranging from well-documented planetary-scale impacts (e.g., cooling by stratospheric aerosol veils) to more subtle or localised processes like ash fertilisation of ocean biota and impacts on cloud properties, atmospheric oxidant levels and terrestrial ecosystems. There is still much to be gained by studying present-day volcanic emissions. This review highlights the need for further work in three example areas. Firstly, to understand regional and arc-scale volcanic emissions, especially cycling of elements through subduction zones, more volatile measurements are needed to contribute to a fundamental and systematic understanding of these processes throughout geological time. Secondly, there is still uncertainty surrounding whether stratospheric ozone depletion following volcanic eruptions results solely from activation of anthropogenic halogen species. We should be poised to study future eruptions into the stratosphere with regard to their impacts and halogen load and work to improve our models and understanding of the relevant underlying processes within the Earth and the atmosphere. Thirdly, we lack a systematic understanding of trace metal volatility from magmas

  16. Model sensitivity of ice flux over the grounding line to present-day climatic forcing and geothermal flux

    NASA Astrophysics Data System (ADS)

    Kleiner, Thomas; Humbert, Angelika

    2016-04-01

    Large uncertainties remain in the current and future contribution to sea level change from Antarctica from observations and numerical flow modelling. Within the SeaRISE project atmospheric, oceanic, and subglacial forcing scenarios were applied to different ice-sheet models to assess Antarctic ice sheet sensitivity over a 500 year timescale. The scenario results have been compared to the individual state of each model at the end of its spin-up. It has been shown, that the model results highly depend on the chosen climate forcing and spin-up strategy. Here we use the Parallel Ice Sheet Model (PISM) to perform spin-up simulations across different data sets for present-day boundary conditions for the Antarctic Ice Sheet (surface temperature, surface mass balance and geothermal flux). The utilized spin-up methods include free evolving and geometry constrained simulations. Here we present our analysis of the ice flux over the grounding line for each set-up and compare the fluxes from large drainage basin units with estimates derived from remote sensing.

  17. Atmospheric transport of persistent organic pollutants to and from the Arctic under present-day and future climate.

    PubMed

    Octaviani, Mega; Stemmler, Irene; Lammel, Gerhard; Graf, Hans F

    2015-03-17

    The long-term atmospheric cycling and fate of persistent organic pollutants under the influence of a changing climate is a concern. A GCM's realization of present-day (1970-1999) and future (2070-2099) climate, the latter under a medium scenario of greenhouse gas emissions, is used to study meridional transports and their correlations with the Arctic and North Atlantic Oscillations (AO and NAO). Regions of import and export maxima into the Arctic are identified along the Arctic Circle. It is found that, under future climate conditions, the net export of PCB153 out of the Arctic will increase. The meridional net flux pattern of this substance is expected to become independent of AO and NAO. For DDT, a trend of decreasing net Arctic import will reverse to an increasing trend 100 years after peak emission, which is partly due to more frequent AO and NAO positive phases. It is concluded that the long-term accumulation trends in the Arctic of other persistent pollutants, including so-called emerging pollutants, are subject to the substances' specific behavior and fate in the environment and need to be studied specifically. PMID:25686012

  18. Evaluation of Present-day Aerosols over China Simulated from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

    NASA Astrophysics Data System (ADS)

    Liao, H.; Chang, W.

    2014-12-01

    High concentrations of aerosols over China lead to strong radiative forcing that is important for both regional and global climate. To understand the representation of aerosols in China in current global climate models, we evaluate extensively the simulated present-day aerosol concentrations and aerosol optical depth (AOD) over China from the 12 models that participated in Atmospheric Chemistry & Climate Model Intercomparison Project (ACCMIP), by using ground-based measurements and satellite remote sensing. Ground-based measurements of aerosol concentrations used in this work include those from the China Meteorological Administration (CMA) Atmosphere Watch Network (CAWNET) and the observed fine-mode aerosol concentrations collected from the literature. The ground-based measurements of AOD in China are taken from the AErosol RObotic NETwork (AERONET), the sites with CIMEL sun photometer operated by Institute of Atmospheric Physics, Chinese Academy of Sciences, and from Chinese Sun Hazemeter Network (CSHNET). We find that the ACCMIP models generally underestimate concentrations of all major aerosol species in China. On an annual mean basis, the multi-model mean concentrations of sulfate, nitrate, ammonium, black carbon, and organic carbon are underestimated by 63%, 73%, 54%, 53%, and 59%, respectively. The multi-model mean AOD values show low biases of 20-40% at studied sites in China. The ACCMIP models can reproduce seasonal variation of nitrate but cannot capture well the seasonal variations of other aerosol species. Our analyses indicate that current global models generally underestimate the role of aerosols in China in climate simulations.

  19. Natural change and human impact in a present-day fluvial catchment: The Geul River, Southern Netherlands

    NASA Astrophysics Data System (ADS)

    Vandenberghe, J.; de Moor, J. J. W.; Spanjaard, G.

    2012-07-01

    The Geul River has a long history of channel straightening and bank protection, but also has several natural meandering parts. In addition, some formerly 'fixed' or 'protected' stretches of the river have been allowed to meander freely since 1988. Therefore, it represents an ideal case for evaluating the contribution of human interference to the intrinsic evolution of the river. In this paper, we compare the response of selected (not protected) reaches of the present-day river to different human modifications. The river banks were labelled as "stable", "unstable" or "erosive". As might be expected, stretches with a high sinuosity have a high percentage of erosive and unstable bank length, while low-sinuosity stretches experience hardly any erosion. The amount of lateral erosion and sedimentation in natural situations is compared with that in situations with different bank protection and stabilization types. Erosion rates may locally attain up to 2 m per year. Detailed grain-size analysis of point-bar sections enable distinction of successive fining-up sequences. Vertical aggradation rates within the point-bars are up to 0.15 m yr- 1. The highest rates are found in the youngest point-bars. Collectively, the results of this study show that when bank protection is removed, the freely meandering river creates its own specific ecosystems and retention capacity increases. Such a return to natural environmental and ecological conditions is in accordance with the objectives of the European Water Framework Directive.

  20. Present-Day Crustal Vertical Motion Around the Ordos Block Constrained by Precise Leveling and GPS Data

    NASA Astrophysics Data System (ADS)

    Hao, Ming; Wang, Qingliang; Cui, Duxin; Liu, Liwei; Zhou, Lin

    2016-06-01

    Precise leveling data observed in the period of 1970-2014 around the Ordos block were collected and processed to estimate present-day crustal vertical movement. Vertical rates of 6 GPS sites were employed as a priori constraints to define the reference frame. The velocity field shows that the interior of the Ordos block moves upward at a rate of 3 mm/a as a stable block. With respect to the central Ordos, the grabens and rifts around the Ordos block are undergoing subsidence, while the northeastern and southwestern Ordos uplift at the average rates of 2 and 1 mm/a, respectively. To the southeastern margin of the Ordos block, the Weihe and southern Shanxi grabens are subsiding at the rates of 4-6 mm/a. The subsidence of the Shanxi graben indicates that the graben is experiencing extensional movement on a long timescale. To the northwestern margin of the Ordos block, the Hetao and Yinchuan rifts are subsiding at the rates of 2-3 mm/a. A 2-D buried faulting model is used to infer the normal or reverse dip-slip rates. Our solution shows that most of the normal slip rates along the faults in the grabens and rifts are ~2 mm/a.

  1. Global connections between aeolian dust, climate and ocean biogeochemistry at the present day and at the last glacial maximum

    NASA Astrophysics Data System (ADS)

    Maher, B. A.; Prospero, J. M.; Mackie, D.; Gaiero, D.; Hesse, P. P.; Balkanski, Y.

    2010-04-01

    Palaeo-dust records in sediments and ice cores show that wind-borne mineral aerosol ('dust') is strongly linked with climate state. During glacial climate stages, for example, the world was much dustier, with dust fluxes two to five times greater than in interglacial stages. However, the influence of dust on climate remains a poorly quantified and actively changing element of the Earth's climate system. Dust can influence climate directly, by the scattering and absorption of solar and terrestrial radiation, and indirectly, by modifying cloud properties. Dust transported to the oceans can also affect climate via ocean fertilization in those regions of the world's oceans where macronutrients like nitrate are abundant but primary production and nitrogen fixation are limited by iron scarcity. Dust containing iron, as fine-grained iron oxides/oxyhydroxides and/or within clay minerals, and other essential micronutrients (e.g. silica) may modulate the uptake of carbon in marine ecosystems and, in turn, the atmospheric concentration of CO 2. Here, in order to critically examine past fluxes and possible climate impacts of dust in general and iron-bearing dust in particular, we consider present-day sources and properties of dust, synthesise available records of dust deposition at the last glacial maximum (LGM); evaluate the evidence for changes in ocean palaeo-productivity associated with, and possibly caused by, changes in aeolian flux to the oceans at the LGM; and consider the radiative forcing effects of increased LGM dust loadings.

  2. Present-Day Crustal Vertical Motion Around the Ordos Block Constrained by Precise Leveling and GPS Data

    NASA Astrophysics Data System (ADS)

    Hao, Ming; Wang, Qingliang; Cui, Duxin; Liu, Liwei; Zhou, Lin

    2016-09-01

    Precise leveling data observed in the period of 1970-2014 around the Ordos block were collected and processed to estimate present-day crustal vertical movement. Vertical rates of 6 GPS sites were employed as a priori constraints to define the reference frame. The velocity field shows that the interior of the Ordos block moves upward at a rate of 3 mm/a as a stable block. With respect to the central Ordos, the grabens and rifts around the Ordos block are undergoing subsidence, while the northeastern and southwestern Ordos uplift at the average rates of 2 and 1 mm/a, respectively. To the southeastern margin of the Ordos block, the Weihe and southern Shanxi grabens are subsiding at the rates of 4-6 mm/a. The subsidence of the Shanxi graben indicates that the graben is experiencing extensional movement on a long timescale. To the northwestern margin of the Ordos block, the Hetao and Yinchuan rifts are subsiding at the rates of 2-3 mm/a. A 2-D buried faulting model is used to infer the normal or reverse dip-slip rates. Our solution shows that most of the normal slip rates along the faults in the grabens and rifts are ~2 mm/a.

  3. A novel GIS-based tool for estimating present-day ocean reference depth using automatically processed gridded bathymetry data

    NASA Astrophysics Data System (ADS)

    Jurecka, Mirosława; Niedzielski, Tomasz; Migoń, Piotr

    2016-05-01

    This paper presents a new method for computing the present-day value of the reference depth (dr) which is an essential input information for assessment of past sea-level changes. The method applies a novel automatic geoprocessing tool developed using Python script and ArcGIS, and uses recent data about ocean floor depth, sediment thickness, and age of oceanic crust. The procedure is multi-step and involves creation of a bathymetric dataset corrected for sediment loading and isostasy, delineation of subduction zones, computation of perpendicular sea-floor profiles, and statistical analysis of these profiles versus crust age. The analysis of site-specific situations near the subduction zones all around the world shows a number of instances where the depth of the oceanic crust stabilizes at a certain level before reaching the subduction zone, and this occurs at depths much lower than proposed in previous approaches to the reference depth issue. An analysis of Jurassic and Cretaceous oceanic lithosphere shows that the most probable interval at which the reference depth occurs is 5300-5800 m. This interval is broadly consistent with dr estimates determined using the Global Depth-Heatflow model (GDH1), but is significantly lower than dr estimates calculated on a basis of the Parsons-Sclater Model (PSM).

  4. Transient climate simulation from the Maunder Minimum to present day using prescribed changes in GHG, total/spectral solar irradiance and ozone

    NASA Astrophysics Data System (ADS)

    Spangehl, Thomas; Cubasch, Ulrich; Schimanke, Semjon

    A fully coupled AO-GCM including representation of the middle atmosphere is used for tran-sient simulation of climate from 1630 to 2000 AD. For better representation of changes in the UV/visible part of the solar spectrum an improved short-wave radiation scheme is implemented. The model is driven by changes in GHG concentrations, solar activity and volcanic eruptions. Solar variability is introduced via changes in total/spectral solar irradiance (TSI/SSI) and pre-scribed changes in stratospheric ozone. The secular trend in TSI is in the range of 0.1 percent increase from Maunder Minimum to present-day. Volcanic eruptions are represented via abrupt reduction in TSI. With the applied forcings the model does not simulate a clear reduction of the annual Northern Hemisphere (NH) mean near surface temperature during Maunder Minimum. By contrast the Dalton Minimum is characterized by distinct cooling and there is a significant raise of NH mean near surface temperature until the end of the 20th century. Focusing on the North Atlantic/European region the winter mean near surface temperature change pat-tern from Late Maunder Minimum (1675-1715) to present-day (1960-1990) reveals maximum warming over north-eastern Europe and cooling over the western North Atlantic with maxi-mum cooling west of Greenland. These changes can partly be explained by a shift of the NAO towards a more positive phase. The simulated changes in tropospheric circulation are discussed with special emphasize on the role of the solar forcing. Besides the stratospheric solar forcing which may affect NAO variability via downward propagation of the solar signal from the strato-sphere to the troposphere the magnitude of the secular trend in TSI might play a role. For the period from Maunder Minimum to present-day the simulation shows less near surface temper-ature increase especially over arctic regions when compared to simulations performed with the same model including the standard radiation scheme but

  5. The Herschel view of the dominant mode of galaxy growth from z = 4 to the present day

    NASA Astrophysics Data System (ADS)

    Schreiber, C.; Pannella, M.; Elbaz, D.; Béthermin, M.; Inami, H.; Dickinson, M.; Magnelli, B.; Wang, T.; Aussel, H.; Daddi, E.; Juneau, S.; Shu, X.; Sargent, M. T.; Buat, V.; Faber, S. M.; Ferguson, H. C.; Giavalisco, M.; Koekemoer, A. M.; Magdis, G.; Morrison, G. E.; Papovich, C.; Santini, P.; Scott, D.

    2015-03-01

    our findings on the cosmic SFR history and on the origin of present-day stars: more than two-thirds of present-day stars must have formed in a regime dominated by the "main sequence" mode. As a consequence we conclude that, although omnipresent in the distant Universe, galaxy mergers had little impact in shaping the global star formation history over the last 12.5 billion years. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Appendices are available in electronic form at http://www.aanda.org

  6. Present-day deformation in NE Iran and the South Caspian constraint by Global Positioning System measurements

    NASA Astrophysics Data System (ADS)

    Mousavi, Z.; Walpersdorf, A.; Walker, R. T.; Tavakoli, F.; Pathier, E.; Nankali, H.; Nilfouroushan, F.; Aghamohammadi, A.; Djamour, Y.

    2012-12-01

    The continental collision between Arabia, the Eurasia and distribution of earthquake epicenters show that most of the deformation is accommodated within the political borders of Iran. In recent years, constraints from GPS, seismology and geological estimates of fault slip-rate have allowed considerable advances in understanding the rates and kinematics of faulting across many parts of Iran. However, until now, only little is known on the present-day distribution of strain across the eastern and northeastern parts of the country, such that it has been difficult to assess the rates of faulting, the related earthquake hazard, and the relationship between the active faults and the overall tectonic motions. This area is one of the most densely populated regions of Iran with almost 6.5 million habitants and a significant number of historical earthquakes like the Qumis 856 A.D earthquake with 200.000 victims. But while eastern Alborz and Kopeh Dagh are clearly regions of active faulting, a lack of instrumental earthquakes is presently observed, making this area particularly interesting for hazard assessment studies. The sparse GPS measurements in NE Iran provide only limited constraints on the applicability of different kinematic scenarios that have been proposed to explain the role of the observed faults. Here, we present a velocity field, composed from 47 GPS stations (20 campaign and 27 permanent), recording over up to 11 years, and covering the entire NE of Iran. This new GPS velocity field helps to investigate how northward directed Arabia-Eurasia shortening is accommodated at the northern boundary of the deforming zone. A regional deformation field for NE Iran has been estimated from the GPS measurements. It shows how the incoming ~7 mm/yr of NS shortening between Central Iran and Eurasia is accommodated in Alborz, Binalud and Kopeh Dagh. The shortening rate decreases toward the east and dies out at the Afghanistan border. The deformation pattern is contrasted along

  7. Modeling of Present-Day Atmosphere and Ocean Non-Tidal De-Aliasing Errors for Future Gravity Mission Simulations

    NASA Astrophysics Data System (ADS)

    Bergmann-Wolf, I.; Dobslaw, H.; Mayer-Gürr, T.

    2015-12-01

    A realistically perturbed synthetic de-aliasing model consistent with the updated Earth System Model of the European Space Agency (Dobslaw et al., 2015) is now available for the years 1995 -- 2006. The data-set contains realizations of (i) errors at large spatial scales assessed individually for periods between 10 -- 30, 3 -- 10, and 1 -- 3 days, the S1 atmospheric tide, and sub-diurnal periods; (ii) errors at small spatial scales typically not covered by global models of atmosphere and ocean variability; and (iii) errors due to physical processes not represented in currently available de-aliasing products. The error magnitudes for each of the different frequency bands are derived from a small ensemble of four atmospheric and oceanic models. In order to demonstrate the plausibility of the error magnitudes chosen, we perform a variance component estimation based on daily GRACE normal equations from the ITSG-Grace2014 global gravity field series recently published by the University of Graz. All 12 years of the error model are used to calculate empirical error variance-covariance matrices describing the systematic dependencies of the errors both in time and in space individually for five continental and four oceanic regions, and daily GRACE normal equations are subsequently employed to obtain pre-factors for each of those matrices. For the largest spatial scales up to d/o = 40 and periods longer than 24 h, errors prepared for the updated ESM are found to be largely consistent with noise of a similar stochastic character contained in present-day GRACE solutions. Differences and similarities identified for all of the nine regions considered will be discussed in detail during the presentation.Dobslaw, H., I. Bergmann-Wolf, R. Dill, E. Forootan, V. Klemann, J. Kusche, and I. Sasgen (2015), The updated ESA Earth System Model for future gravity mission simulation studies, J. Geod., doi:10.1007/s00190-014-0787-8.

  8. Spatial distribution of precipitation annual cycles over South Africa in 10 CORDEX regional climate model present-day simulations

    NASA Astrophysics Data System (ADS)

    Favre, Alice; Philippon, Nathalie; Pohl, Benjamin; Kalognomou, Evangelia-Anna; Lennard, Christopher; Hewitson, Bruce; Nikulin, Grigori; Dosio, Alessandro; Panitz, Hans-Juergen; Cerezo-Mota, Ruth

    2016-03-01

    This study presents an evaluation of the ability of 10 regional climate models (RCMs) participating in the COordinated Regional climate Downscaling Experiment-Africa to reproduce the present-day spatial distribution of annual cycles of precipitation over the South African region and its borders. As found in previous studies, annual mean precipitation is quasi-systematically overestimated by the RCMs over a large part of southern Africa south of about 20°S and more strongly over South Africa. The spatial analysis of precipitation over the studied region shows that in most models the distribution of biases appears to be linked to orography. Wet biases are quasi-systematic in regions with higher elevation with inversely neutral to dry biases particularly in the coastal fringes. This spatial pattern of biases is particularly obvious during summer and specifically at the beginning of the rainy season (November and December) when the wet biases are found to be the strongest across all models. Applying a k-means algorithm, a classification of annual cycles is performed using observed precipitation data, and is compared with those derived from modeled data. It is found that the in-homogeneity of the spatial and temporal distribution of biases tends to impact the modeled seasonality of precipitation. Generally, the pattern of rainfall seasonality in the ensemble mean of the 10 RCMs tends to be shifted to the southwest. This spatial shift is mainly linked to a strong overestimation of convective precipitation at the beginning of the rainy season over the plateau inducing an early annual peak and to an underestimation of stratiform rainfall in winter and spring over southwestern South Africa.

  9. The Secrets of the Nearest Starburst Cluster. II. The Present-Day Mass Function in NGC 3603

    NASA Astrophysics Data System (ADS)

    Stolte, Andrea; Brandner, Wolfgang; Brandl, Bernhard; Zinnecker, Hans

    2006-07-01

    Based on deep Very Large Telescope Infrared Spectrometer and Array Camera JHK photometry, we have derived the present-day mass function (MF) of the central starburst cluster NGC 3603 YC (Young Cluster) in the giant H II region NGC 3603. The effects of field contamination, individual reddening, and a possible binary contribution are investigated. The MF slopes resulting from the different methods are compared and lead to a surprisingly consistent cluster MF with a slope of Γ=-0.9+/-0.15. Analyzing different radial annuli around the cluster core, no significant change in the slope of the MF is observed. However, mass segregation in the cluster is evidenced by the increasing depletion of the high-mass tail of the stellar mass distribution with increasing radius. We discuss the indications of mass segregation with respect to the changes observed in the binned and cumulative stellar MFs and argue that the cumulative function, as well as the fraction of high- to low-mass stars, provides better indicators for mass segregation than the MF slope alone. Finally, the observed MF and starburst morphology of NGC 3603 YC are discussed in the context of massive local star-forming regions such as the Galactic center Arches cluster, R136/30 Dor in the LMC, and the Orion Trapezium cluster, all providing resolved templates for extragalactic star formation. Despite the similarity in the observed MF slopes, dynamical considerations suggest that the starburst clusters do not form gravitationally bound systems over a Hubble time. Both the environment (gravitational potential of the Milky Way) and the concentration of stars in the cluster core determine the dynamical stability of a dense star cluster, such that the long-term evolution of a starburst is not exclusively determined by the stellar evolution of its members, as frequently assumed for globular cluster systems. Based on observations obtained at the ESO Very Large Telescope on Paranal, Chile, under programs 63.I-0015 and 65.I

  10. Impact of the Yakutat indentor corner on present-day tectonics and fault activity in SE Alaska - SW Yukon

    NASA Astrophysics Data System (ADS)

    Mazzotti, S.; Marechal, A.; Ritz, J. F.; Ferry, M. A.

    2015-12-01

    We present an active tectonic model of the SE Alaska - SW Yukon region based principally on the integration of recent GPS velocity data and new fault-slip rates derived from geomorphology. In this region, the Yakutat collision results in complex tectonics with patterns of strain localization and strain partitioning that strongly vary across the various mountain ranges and active faults. We propose that deformation and fault activity in the St. Elias and Chugach Mountains are primarily controlled by the eastern syntaxis of the Yakutat collision, which produces a semi-radial tectonic pattern: Velocities, principal horizontal shortening rates, and maximum horizontal stress orientations rotate by 60 - 80 ° around the syntaxis, from roughly parallel to the relative Pacific - North America motion at the front of the collision to roughly orthogonal southeast of the syntaxis. The interaction between this strain pattern and major inherited tectonic structures inland of the collision zone (i.e., Denali and Duke River Faults) results in various reactivation modes of these structures. Specifically, the Denali Fault shows a very pronounced lateral variations of activity from ~12 mm/a of dextral slip rate in its central section to ~1 mm/a of mostly shortening slip rate along its southern section. This marked change of activity is associated with a possible relay system where the Duke River and Totschunda Faults accommodate a major part (8 - 12 mm/a) of the inland strain transfer directly in front of the syntaxis. This new tectonic model retains some questions, in particular regarding the mechanisms of deformation and strain transfer (1) from the syntaxis to the Duke River - Totschunda system and (2) at the junction between Totschunda and Denali Faults. Numerical models of present-day deformation may help address these issues and provide information about relative strength of the various crustal and inherited fault elements of this system.

  11. Historical and Present Day Mercury Contamination From Gold Mining in Three Feeding Guilds of Bats From the Peruvian Amazon

    NASA Astrophysics Data System (ADS)

    Kumar, A.; Divoll, T.

    2014-12-01

    Miners in many countries use mercury as an amalgam to separate gold from river sediments. In the last twenty years the price of gold has risen and the number of small-scale, artisanal gold mining operations in the Amazon basin have also increased. The influx of mercury into natural river systems has detrimental consequences for the surrounding ecosystem and for organisms, particularly those at higher trophic levels. Toxic mercury levels have been shown to impair reproductive, neurological and behavioral functioning of organisms. I used bats (Chiroptera) as a mammalian model system to study mercury contamination and accumulation due to gold mining from field caught and museum collection specimens in Amazonian Perú and showed that: (1) Total mercury concentrations in Amazonian bat species have increased over time since the 1920's; (2) Bat species from sites with current active mining have higher concentrations of mercury than non-mining sites, with some species having levels exceeding those considered toxic for mammals; (3) Higher trophic levels of bats (piscivores and insectivores) bioaccumulate more mercury than bats of lower trophic levels (frugivores); (4) Bats located in present day uncontaminated sites have the same mercury levels as bats collected in the 1920's from the Amazon basin. The variety of bat feeding guilds allowed for a comparison of how mercury accumulation is affected by diet within one taxonomic order. The novel use of museum specimens allowed for a look back into the historical timeline of mercury contamination in the Amazon basin. Bats represent a new and exciting study system since, like humans, they are mammals and should therefore show similar neurochemical and behavioral responses to this toxic element.

  12. Multivariate spatio-temporal modelling for assessing Antarctica's present-day contribution to sea-level rise

    PubMed Central

    Zammit-Mangion, Andrew; Rougier, Jonathan; Schön, Nana; Lindgren, Finn; Bamber, Jonathan

    2015-01-01

    Antarctica is the world's largest fresh-water reservoir, with the potential to raise sea levels by about 60 m. An ice sheet contributes to sea-level rise (SLR) when its rate of ice discharge and/or surface melting exceeds accumulation through snowfall. Constraining the contribution of the ice sheets to present-day SLR is vital both for coastal development and planning, and climate projections. Information on various ice sheet processes is available from several remote sensing data sets, as well as in situ data such as global positioning system data. These data have differing coverage, spatial support, temporal sampling and sensing characteristics, and thus, it is advantageous to combine them all in a single framework for estimation of the SLR contribution and the assessment of processes controlling mass exchange with the ocean. In this paper, we predict the rate of height change due to salient geophysical processes in Antarctica and use these to provide estimates of SLR contribution with associated uncertainties. We employ a multivariate spatio-temporal model, approximated as a Gaussian Markov random field, to take advantage of differing spatio-temporal properties of the processes to separate the causes of the observed change. The process parameters are estimated from geophysical models, while the remaining parameters are estimated using a Markov chain Monte Carlo scheme, designed to operate in a high-performance computing environment across multiple nodes. We validate our methods against a separate data set and compare the results to those from studies that invariably employ numerical model outputs directly. We conclude that it is possible, and insightful, to assess Antarctica's contribution without explicit use of numerical models. Further, the results obtained here can be used to test the geophysical numerical models for which in situ data are hard to obtain. © 2015 The Authors. Environmetrics published by John Wiley & Sons Ltd. PMID:25937792

  13. Changing black carbon transport to the Arctic from present day to the end of 21st century

    NASA Astrophysics Data System (ADS)

    Jiao, Chaoyi; Flanner, Mark G.

    2016-05-01

    Here we explore how climate warming under the Representative Concentration Pathway 8.5 (RCP8.5) impacts Arctic aerosol distributions via changes in atmospheric transport and removal processes. We modify the bulk aerosol module in the Community Atmosphere Model to track distributions and fluxes of 200 black carbon-like tracers emitted from different locations, and we conduct idealized experiments with and without active aerosol deposition. Changing wind patterns, studied in isolation, cause the Arctic burdens of tracers emitted from East Asia and West Europe during winter to increase about 20% by the end of the century while decreasing the Arctic burdens of North American emissions by about 30%. These changes are caused by an altered winter polar dome structure that results from Arctic amplification and inhomogeneous sea ice loss and surface warming, both of which are enhanced in the Chukchi Sea region. The resulting geostrophic wind favors Arctic transport of East Asian emissions while inhibiting poleward transport of North American emissions. When active deposition is also considered, however, Arctic burdens of emissions from northern midlatitudes show near-universal decline. This is a consequence of increased precipitation and wet removal, particularly within the Arctic, leading to decreased Arctic residence time. Simulations with present-day emissions of black carbon indicate a 13.6% reduction in the Arctic annual mean burden by the end of the 21st century, due to warming-induced transport and deposition changes, while simulations with changing climate and emissions under RCP8.5 show a 61.0% reduction.

  14. Life detection at a Mars analogue site of present-day serpentinization in the Tablelands Ophiolite of Newfoundland (Invited)

    NASA Astrophysics Data System (ADS)

    Morrill, P. L.; Szponar, N.; Brazelton, W. J.; Woodruff, Q.; Schrenk, M. O.; Bower, D. M.; Steele, A.

    2010-12-01

    The Tableland Ophiolite was created during the collision of Laurentia and Gondwana continents ca. 470 million years ago. Ultramafic mantle rocks, from the ancient sea bed that once separated these continents, were thrusted westward onto the old continental margin, which is now Western Newfoundland. Weathering due to recent glaciations has left large areas of ultramafic rock at the surface and created fissures for fluid flow. As a result serpentinization is occurring as fresh water penetrates the unaltered ultramafic rock. Serpentinization is of particular interest because, through hydration of ultramafic rock, this reaction produces H2 and the reducing conditions necessary for abiogenic hydrocarbon synthesis, while also producing conditions amenable for chemolithotrophic life. Therefore sites of active serpentinization can be the source of either abiogenic or biogenic organics, or both. Serpentinization is a suspected (past or present) source of (detected or putative) hydrocarbons on Mars, Titan and Europa, hence these astrobodies may be potentially habitable or once habitable environments. The Tablelands Ophiolite is an analogue site that is ideal for testing methods of life detection in an extreme environment of high pH and low microbial biomass characteristic of sites of serpentinization. Multiple ultrabasic reducing springs characteristic of present-day serpentinization have been identified and characterized based on their geochemistry and microbiology. Field-based instruments were deployed for the detection of microbial activity (ATP), microbial cell wall material, and mineralogy, in yet untested high pH and low biomass environment. In this talk I will give an overview of the in situ measurements of life detection and put these measurements in context of geochemistry, microbiology, carbon source and reaction pathways, and I will discuss what we have learned that will help us plan for future mission measurements.

  15. Modelling the economic losses of historic and present-day high-impact winter storms in Switzerland

    NASA Astrophysics Data System (ADS)

    Welker, Christoph; Stucki, Peter; Bresch, David; Dierer, Silke; Martius, Olivia; Brönnimann, Stefan

    2014-05-01

    Severe winter storms such as "Vivian" in February 1990 and "Lothar" in December 1999 are among the most destructive meteorological hazards in Switzerland. Disaster severity resulting from such windstorms is attributable, on the one hand, to hazardous weather conditions such as high wind gust speeds; and on the other hand to socio-economic factors such as population density, distribution of values at risk, and damage susceptibility. For present-day winter storms, the data basis is generally good to describe the meteorological development and wind forces as well as the associated socio-economic impacts. In contrast, the information on historic windstorms is overall sparse and the available historic weather and loss reports mostly do not provide quantitative information. This study illustrates a promising technique to simulate the economic impacts of both historic and present winter storms in Switzerland since end of the 19th century. Our approach makes use of the novel Twentieth Century Reanalysis (20CR) spanning 1871-present. The 2-degree spatial resolution of the global 20CR dataset is relatively coarse. Thus, the complex orography of Switzerland is not realistically represented, which has considerable ramifications for the representation of wind systems that are strongly influenced by the local orography, such as Föhn winds. Therefore, a dynamical downscaling of the 20CR to 3 km resolution using the Weather Research and Forecasting (WRF) model was performed, for in total 40 high-impact winter storms in Switzerland since 1871. Based on the downscaled wind gust speeds and the climada loss model, the estimated economic losses were calculated at municipality level for current economic and social conditions. With this approach, we find an answer to the question what would be the economic losses of e.g. a hazardous Föhn storm - which occurred in northern Switzerland in February 1925 - today, i.e. under current socio-economic conditions. Encouragingly, the pattern of

  16. Impact of urban emission on air-quality over central Europe: present day and future emissions perspective

    NASA Astrophysics Data System (ADS)

    Huszar, Peter; Belda, Michal; Halenka, Tomas; Karlicky, Jan

    2016-04-01

    The purpose of the study is to quantify the impact of present-day and future urban emission from central European cities on the regional air-quality (AQ), based on a modeling couple of the regional climate model RegCM4.2 and the chemistry transport model CAMx, including two-way interactions. A series of simulations was carried out for the present (2001-2010) decade and two future decades (2026-2035 and 2046-2055) either with all urban emissions included (base case) or without considering urban emissions. As we are interested on the impact of emission changes only, the impact of different driving meteorological conditions in the future (due to climate change) are not considered. The emissions used is the TNO MEGAPOLI European emission database that includes country/sector based scenarios for years 2030 and 2050, which were used for the encompassing decades. Further, the sensitivity of ozone production to urban emissions was examined by performing reduction experiments with -20% emission perturbation of NOx and/or NMVOC. The model was also validated using surface measurements of key pollutants. Selected air-quality measures were used as metrics describing the cities emission impact on regional air pollution. Due to urban emissions, significant ozone titration occurs over cities while over rural areas further from, ozone production is modeled, mainly in terms of number of exceedances and accumulated exceedances over the threshold of 40 ppbv. Urban NOx, SO2 and PM2.5 emissions also significantly contribute to concentrations in the cities themselves (up to 50-70% for NOx and SO2 , and up to 55% for PM2.5), but the contribution is large over rural areas as well (10-20%). Although air pollution over cities is largely determined by the local urban emissions, considerable (often a few tens of %) fraction of the concentration is attributable to other sources from rural areas and minor cities. The future urban emission AQ fingerprint is, in general, slightly smaller than in

  17. Dusty wind of W Hydrae. Multi-wavelength modelling of the present-day and recent mass loss

    NASA Astrophysics Data System (ADS)

    Khouri, T.; Waters, L. B. F. M.; de Koter, A.; Decin, L.; Min, M.; de Vries, B. L.; Lombaert, R.; Cox, N. L. J.

    2015-05-01

    Context. Low- and intermediate-mass stars go through a period of intense mass-loss at the end of their lives, during the asymptotic giant branch (AGB) phase. While on the AGB a significant part, or even most, of their initial mass is expelled in a stellar wind. This process controls the final stages of the evolution of these stars and contributes to the chemical evolution of galaxies. However, the wind-driving mechanism of AGB stars is not yet well understood, especially so for oxygen-rich sources. Characterizing both the present-day mass-loss rate and wind structure and the evolution of the mass-loss rate of such stars is paramount to advancing our understanding of this processes. Aims: We study the dusty wind of the oxygen-rich AGB star W Hya to understand its composition and structure and shed light on the mass-loss mechanism. Methods: We modelled the dust envelope of W Hya using an advanced radiative transfer code. We analysed our dust model in the light of a previously calculated gas-phase wind model and compared it with measurements available in the literature, such as infrared spectra, infrared images, and optical scattered light fractions. Results: We find that the dust spectrum of W Hya can partly be explained by a gravitationally bound dust shell that probably is responsible for most of the amorphous Al2O3 emission. The composition of the large (~0.3 μm) grains needed to explain the scattered light cannot be constrained, but probably is dominated by silicates. Silicate emission in the thermal infrared was found to originate from beyond 40 AU from the star. In our model, the silicates need to have substantial near-infrared opacities to be visible at such large distances. The increase in near-infrared opacity of the dust at these distances roughly coincides with a sudden increase in expansion velocity as deduced from the gas-phase CO lines. The dust envelope of W Hya probably contains an important amount of calcium but we were not able to obtain a dust

  18. Investigating the Present Day Cosmic Dust Flux at the Earth's Surface: Initial Results from the Kwajalein Micrometeorite Collection

    NASA Technical Reports Server (NTRS)

    Wozniakiewicz, P. J.; Bradley, J. P.; Price, M. C.; Zolensky, M. E.; Ishii, H. A.; Brownlee, D. E.; Russell, S. S.

    2014-01-01

    Examination of impact craters on the Long Duration Exposure Facility satellite indicate a present day micrometeoroid flux of approx. 30,000 tonnes [1 after 2]. But what portion of this material arrives at the Earth's surface as micrometeorites? Studies of available micrometeorite collections from deep sea sediments [e.g. 3], Greenland blue ice [e.g. 4] and the South Pole water well [e.g. 1] may be complicated by terrestrial weathering and, in some cases, collection bias (magnetic separation for deep sea sediments) and poorly constrained ages. We have recently set up a micrometeorite collection station on Kwajalein Island in the Republic of the Marshall Islands in the Pacific Ocean, using high volume air samplers to collect particles directly from the atmosphere. By collecting in this way, the terrestrial age of the particles is known, the weathering they experience is minimal, and we are able to constrain particle arrival times. Collecting at this location also exploits the considerably reduced anthropogenic background [5]. Method: High volume air samplers were installed on top of the two-story airport building on Kwajalein. These were fitted with polycarbonate membrane filters with 5µm diameter perforations. The flow rates were set to 0.5m3/min, and filters were changed once a week. After collection, filters were washed to remove salt and concentrate particles [see 5] in preparation for analysis by SEM. Results and Discussion: A selection of filters have been prepared and surveyed. Due to their ease of identification our initial investigations have focused on particles resembling cosmic spherules. The spheres can be divided into three main groups: 1. Silicate spherules rich in Al, Ca, K and Na (to varying degrees), 2. Silicate spherules rich in Mg and Fe and 3. Fe-rich spherules. Group 1 spherules are often vesiculated and can occur as aggregates. They are similar in appearance and composition to volcanic microspheres [e.g. 6] and are thus likely terrestrial in

  19. High natural erosion rates are the backdrop for present-day soil erosion in the agricultural Middle Hills of Nepal

    NASA Astrophysics Data System (ADS)

    West, A. J.; Arnold, M.; AumaItre, G.; Bourles, D. L.; Keddadouche, K.; Bickle, M.; Ojha, T.

    2015-07-01

    Although agriculturally accelerated soil erosion is implicated in the unsustainable environmental degradation of mountain environments, such as in the Himalaya, the effects of land use can be challenging to quantify in many mountain settings because of the high and variable natural background rates of erosion. In this study, we present new long-term denudation rates, derived from cosmogenic 10Be analysis of quartz in river sediment from the Likhu Khola, a small agricultural river basin in the Middle Hills of central Nepal. Calculated long-term denudation rates, which reflect background natural erosion processes over 1000+ years prior to agricultural intensification, are similar to present-day sediment yields and to soil loss rates from terraces that are well maintained. Similarity in short- and long-term catchment-wide erosion rates for the Likhu is consistent with data from elsewhere in the Nepal Middle Hills but contrasts with the very large increases in short-term erosion rates seen in agricultural catchments in other steep mountain settings. Our results suggest that the large sediment fluxes exported from the Likhu and other Middle Hills rivers in the Himalaya are derived in large part from natural processes, rather than from soil erosion as a result of agricultural activity. Catchment-scale erosional fluxes may be similar over short and long timescales if both are dominated by mass wasting sources such as gullies, landslides, and debris flows (e.g., as is evident in the landslide-dominated Khudi Khola of the Nepal High Himalaya, based on compiled data). As a consequence, simple comparison of catchment-scale fluxes will not necessarily pinpoint land use effects on soils where these are only a small part of the total erosion budget, unless rates of mass wasting are also considered. Estimates of the mass wasting contribution to erosion in the Likhu imply catchment-averaged soil production rates on the order of ~ 0.25-0.35 mm yr-1, though rates of mass wasting are

  20. Comparison of statistical and dynamical downscaling of extreme precipitations over France in present-day and future climate

    NASA Astrophysics Data System (ADS)

    Colin, Jeanne; Déqué, Michel; Sanchez Gomez, Emila; Somot, Samuel

    2010-05-01

    We present a comparison of two downscaling methods of extreme precipitations over France at a climatic time scale : a dynamical one performed with the Regional Climate Model ALADIN-Climate used at a resolution of 12 km, and a statistical one based on the weather regime approach and using the analog methodology to reconstruct daily fields of precipitations at a 8 km resolution. We focus on the most heavy precipitations of the area of interest, which occur in southeastern France in Autumn. Those involve small-scale processes than can be explicitly resolved only with 2-1 km resolution non-hydrostatic models. However, such models can not be used for climate simulations because of their computational cost is still too high. Yet these extreme events cause rather heavy damages, so that their possible evolution in the context of climate change is of great concern. Thus, there is strong need in assessing downscaling methods' ability to represent them. First, we downscale the low-resolution ERA40 re-analysis over the 1958-2000 time period with ALADIN-Climate, and from the year 1980 to the year 2000 with the statistical method. Then, we apply a quantile-quantile correction to the daily precipitations of the last twenty years of the ALADIN-Climate simulation. The correction rates are computed over the first part of the simulation (1958-1979) using a high-resolution gridded database : the SAFRAN analysis, which provides series of hourly fields for the 1958-2008 period over the french territory at a 8 km resolution. We assess the performances of each downscaling method in present-day climate by comparing the simulated precipitations to the SAFRAN database. The use of the ERA40 re-analysis allows to reproduce the real chronology in both downscalings, which enables to analyze the results not only from a statistical point of view but also through day-to-day diagnosis such as time correlations or spatial patterns of rain for given extreme events. Secondly, we apply these downscaling

  1. Present-day vertical displacements in the north-western Alps and southern Jura Mountains: Data from leveling comparisons

    NASA Astrophysics Data System (ADS)

    Jouanne, F.; MéNard, G.; Darmendrail, X.

    1995-06-01

    Two high-precision leveling networks were successively surveyed in France, the NGF, measured during the 1886-1907 period, and the IGN69, measured from 1965 to 1979. The accuracy of these levelings (standard deviation of 1.8mm/√km to 3.8mm/√km) allows us to compute the vertical displacements of the benchmarks between two different eras. The results indicate the occurrence of discrete zones of uplift and subsidence: (1) a regional uplift (up to 1.4 mm/yr) of the Subalpine Massifs; (2) an important uplift of the internal Jura (up to 2 mm/yr); (3) a relative subsidence of the southern part of the Jura (0.8 mm/yr); and (4) a relative subsidence of the Bresse Basin with respect to the external Jura. Comparing the spatial distribution of zones of uplift and their respective vertical displacement rates with a regional structural cross section leads to the conclusion that present-day uplift of the Belledonne and Bornes Massifs and of the internal parts of the Jura Mountains, can be explained by crustal shortening along a major basement-involving thrust fault. This fault ramps up under the Bornes Massif from a depth of 12 km to 7 km, turns into a flat under the Molasse Basin, ramps up to the top of the basement at the north-eastern margin of the internal Jura Mountains, and reaches the surface in the external Jura. The Salève ramp-anticline is carried by a bifurcation of this thrust. Horizontal displacement rates of 6 mm/yr at the Bornes ramp, 2 mm/yr at the Salève ramp, and 4 mm/yr at the internal Jura ramp have been determined by inversion of profiles of uplift rates. Whether this basement-involving thrust fault was already active during the Miocene main folding phase of the Jura Mountains or whether it was activated only during Pliocene-Pleistocene times is subject to debate.

  2. Effects of the past- and present-day ice melting on observed uplift rates in Southeast Alaska

    NASA Astrophysics Data System (ADS)

    Sato, T.; Larsen, C. F.; Miura, S.; Ohta, Y.; Fujimoto, H.; Sun, W.; Sugano, T.; Kaufman, A. M.; Motyka, R. J.; Freymueller, J. T.

    2009-12-01

    A joint Japanese-US observation project called ISEA (International geodetic project in South-Eastern Alaska) was initiated in 2005 to follow up the work of the University of Alaska Fairbanks (UAF) by adding new geodetic data sets (Miura et al., 2007). Based on 91 improved GPS velocities and the proposed ice loss models by Larsen et al. (2004, 2005, 2007) and by Tushingham and Peltier (1991), we estimated three effects: present-day ice melting (PDIM), post-little ice age (LIA) melting, and deglaciation following the last glacier maximum (LGM). We also have reevaluated the thickness of lithosphere and the viscosities of the mantle including that of asthenosphere in the region. The effects of LGM deglaciation were computed based on the ICE3G model (Tushingham and Peltier, 1991). Although the effect of LGM ice is small in SE-AK (i.e. 2 mm/yr at the maximum), we have confirmed that, by comparing with the misfits obtained by correcting for only two effects of PDIM and LIA, correcting for the LGM effect can improve the chi^2 of misfits by about 0.5 %. We estimated the effect of post-LIA ice melting based on the melting history proposed by Larsen et al. (2004, 2005). For the viscoelastic structure, we have tested two different kinds of mantle viscosity structure: a two-layer model similar to the model used by Larsen et al. (2005) and a 4-layer model. To search the best combination of the lithosphere thickness and the mantle viscosities, the combinations of the rheological parameters tested here were 161 in total number. To test the sensitivity of the estimated rheological parameters to the elastic PDIM effects, we have compared two PDIM models; one is EPSL2005 model (Larsen et al., 2005) and the other is JGR2007 model (Larsen et al., 2007). Statistical examinations of the misfits between observations and model predictions, which were based on the magnitudes of the minimum chi^2 and the mean of residuals fitting to a Gaussian function, indicate that the JGR2007 model gives

  3. PRESENT-DAY MASS FUNCTION OF SIX SMALL MAGELLANIC CLOUD INTERMEDIATE-AGE AND OLD STAR CLUSTERS

    SciTech Connect

    Glatt, Katharina; Grebel, Eva K.; Jordi, Katrin; Gallagher, John S. III; Harbeck, Daniel; Da Costa, Gary; Clementini, Gisella; Tosi, Monica; Nota, Antonella; Sabbi, Elena; Sirianni, Marco

    2011-08-15

    We determined the present-day mass functions (PDMFs) of the five intermediate-age star clusters Lindsay 1, Kron 3, NGC 339, NGC 416, and Lindsay 38 and the old star cluster NGC 121 in the Small Magellanic Cloud (SMC) based on observations with the Hubble Space Telescope Advanced Camera for Surveys. The global PDMFs are well matched by Salpeter-like power laws from their main-sequence turnoffs to {approx}0.6 M{sub sun} with a power-law exponent {alpha} ranging from 1.51 {+-} 0.11 (Lindsay 1) to 2.29 {+-} 0.15 (NGC 339). We derive total stellar masses of {approx}10{sup 5} M{sub sun}, except for Lindsay 38, whose mass is of the order of {approx}10{sup 4} M{sub sun}. Differences between the PDMFs most likely reflect the varying stages of dynamical evolution of the clusters. These SMC clusters do not follow the {alpha} versus concentration parameter c correlation as found for Galactic globular clusters of similar mass. This might be an age effect or due to their location in a galaxy where bulge and disk crossings do not play a role. No correlation is found between {alpha} and the cluster core and tidal radii (r{sub c} and r{sub t} , respectively), the half-light radii r{sub h} , age, central surface brightness, metallicity, and galactocentric radius r{sub gc}. All six clusters mass-segregated to different degrees. The two clusters Lindsay 1 and Kron 3 barely show signs for mass segregation, but have low-mass star deficient global PDMFs and might be the remnants of star clusters whose outer parts were stripped. A trend exists between the degree of mass segregation and the ratio age/relaxation time t{sub r,h}, which indicates the stage of dynamical evolution for a cluster. Our data thus suggest that the SMC clusters in the present sample had a range of initial densities and presumably different amounts of mass loss that led to different rates of dynamical evolution. The clusters' positions in the r{sub h,m}/r{sub t} versus r{sub 0}/r{sub h,m} plane imply that all of the

  4. Hazard responses in the pre-industrial era: vulnerability and resilience of traditional societies to volcanic disasters and the implications for present-day disaster planning

    NASA Astrophysics Data System (ADS)

    Sangster, Heather

    2014-05-01

    A major research frontier in the study of natural hazard research involves unravelling the ways in which societies have reacted historically to disasters, and how such responses influence current policies of disaster reduction. For societies it is common to classify responses to natural hazards into: pre-industrial (folk); industrial; and post-industrial (comprehensive) responses. Pre-industrial societies are characterised by: a pre-dominantly rural location; an agricultural economic focus; artisan handicrafts rather than industrial production, parochialism, with people rarely travelling outside their local area and being little affected by external events and a feudal or semi-feudal social structure. In the past, hazard assessment focused on the physical processes that produced extreme and potentially damaging occurrences, however from the middle of the twenty-first century research into natural hazards has been cast within a framework defined by the polarities (or opposites) of vulnerability and resilience, subject to a blend of unique environmental, social, economic and cultural forces in hazardous areas, that either increase or decrease the impact of extreme events on a given society. In the past decade research of this type has been facilitated by a 'revolution' of source materials across a range of languages and in a variety of electronic formats (e.g. official archives; major contemporary and near-contemporary publications - often available as reprints; national and international newspapers of record; newsreel-films; and, photographs) and in the introduction of more reliable translation software (e.g. Systrans) that provides far more scope to the researcher in the study of natural hazards than was the case even a few years ago. Knowledge of hazard responses in the pre-industrial era is, not only important in its own right because it reveals indigenous strategies of coping, but also informs present-day disaster planners about how people have reacted to past

  5. From past sailors' eras to the present day: scurvy as a surprising manifestation of an uncommon gastrointestinal disease.

    PubMed

    Branquinho, Diogo Ferreira; Pinto-Gouveia, Miguel; Mendes, Sofia; Sofia, Carlos

    2015-01-01

    A 45-year-old man presented with follicular exanthema in his lower limbs, alternating bowel habits and significant weight loss. His medical history included seronegative arthritis, bipolar disease and an inconclusive diagnostic laparoscopy. Diagnostic work up revealed microcytic anaemia and multivitamin deficiency. Skin biopsy of the exanthema suggested scurvy. Owing to these signs of malabsorption, upper endoscopy with duodenal biopsies was performed, exhibiting villous atrophy and extensive periodic acid-Schiff-positive material in the lamina propria, therefore diagnosing Whipple's disease (WD). After starting treatment with ceftriaxone and co-trimoxazole, an impressive recovery was noted, as the wide spectrum of malabsorption signs quickly disappeared. After a year of antibiotics, articular and cutaneous manifestations improved, allowing the patient to stop taking corticosteroids and antidepressants. This truly unusual presentation reflects the multisystemic nature of WD, often leading to misdiagnosis of other entities. Scurvy is a rare finding in developed countries, but its presence should raise suspicion for small bowel disease. PMID:26376699

  6. Present-day submarine hydrothermal activity in the Taupo-Rotorua Zone (Bay of Plenty, New Zealand)

    SciTech Connect

    Osipenko, A.B.; Egorov, Yu.O.; Fazlullin, S.M.; Gavrilenko, G.M.; Shul`kin, V.I.; Chertkova, L.V.

    1994-09-01

    We made detailed descriptions of the structure and material composition of sedimentary and water columns in the vicinity of active submarine hydrothermal activity in the southern part of the Bay of Plenty (North Island, New Zealand). Geophysical methods revealed that the hydrothermal system is confined to a tectonically distinct zone with a sedimentary cover characterized by complex structure. Chemical and mineralogical investigations confirmed that the activity of underwater vents exerts no substantial regional influence on the composition and features of ore mineralization in these formations. It is shown that essentially hydrothermal formations distinguishable within areas of otherwise monotypic sediments directly coincide with zones of hydrothermal discharge in the ocean floor. The absence of pronounced hydrothermal anomalies, together with the presence of {open_quotes}tongues{close_quotes} of anomalous concentrations of water-soluble gases suggests that the discharges are primarily hydrothermal in character.

  7. Present-day Galaxy Evolution through Baryon Flows in the Circumgalactic Medium of the Galactic-Magellanic System

    NASA Astrophysics Data System (ADS)

    Barger, Kathleen Ann

    Galaxy evolution is governed by an intricate ballet of gas flows. To sustain star formation over many billions of years, more gas must inflow than outflow. Although numerous gas clouds surround the Milky Way, their attributes, origins, destinations, and responses to their surroundings need thorough investigation on an individual basis to realize how the entire population affects Galactic evolution. This dissertation hones in on two circumgalactic gas structures near the Milky Way: Complex A and the Magellanic Bridge. Complex A is an elongated gas structure that is traversing the hot Halo of the Milky Way, plummeting towards the Galaxy's disk. The Magellanic Bridge is a bridge of gas and stars that connects the Magellanic Clouds, created by galaxy interactions. In this thesis, I present the results of the highest sensitivity and kinematically resolved Halpha emission-line survey of Complex A and Halpha, [S II], and [N II] surveys of the Magellanic Bridge using the Wisconsin Halpha Mapper to explore their properties, surroundings, origins, and fates to unravel how circumgalactic structures influence galaxy evolution. I find that the observational properties of Complex A closely match with radiative transfer model predictions of a cloud ionized by the Milky Way and extragalactic background, implying a 5% escape fraction of ionizing photons from the Galactic disk. The multiline observations and modeling place the cloud's metallicity below solar. These results combined with other studies suggests the cloud has an intergalactic medium origin. I find that the global distribution of the warm ionized gas traces the neutral gas in the Magellanic Bridge. These observations place the ionized gas mass between (0.7 -- 1.6) x 108 solar masses, implying an ionization fraction of 25 -- 33% and a 5% maximum escape fraction of ionizing photons from the Magellanic Clouds. The line ratios reveal that the physical state of the the SMC-Tail and the LMC-Bridge interface regions differ

  8. Intraseasonal Variability of the South Asian Summer Monsoon: Present-day Simulations with the Regional Atmospheric Model HIRHAM5

    NASA Astrophysics Data System (ADS)

    Hanf, F. S.; Rinke, A.; Dethloff, K.

    2014-12-01

    Since 1950, observations show a robust negative trend of the seasonal rainfall associated with the South Asian summer monsoon over India coinciding with a continuous decrease in surface solar radiation ("dimming") over South Asia due to an increase of local aerosol emissions. On the intraseasonal timescale the summer monsoon fluctuates between periods of enhanced and reduced rainfall. The frequency of occurrence of these active and breaks monsoon phases affects directly the seasonal monsoon rainfall. This study investigates the regional pattern and changes of the South Asian monsoon for the period 1979-2012 using the regional atmospheric model HIRHAM5 with a horizontal resolution of 0.25° forced at the lateral and lower boundaries with ERA-Interim reanalysis data. Despite the dry bias in the mean summer monsoon rainfall over the Indian landmass, the simulated temperature and atmospheric circulation patterns are in agreement with the ERA-Interim reanalysis indicating a realistic representation of important dynamical summer monsoon features. In addition, mechanisms which controls active and break phases within the summer monsoon season are analyzed using daily outgoing longwave radiation model data as an identification tool of monsoon breaks as proposed by Krishnan et al. (2000). Model results reveal an increasing trend of the cumulative monsoon break days of around 1.4 days per year during the last 30 years. The possible link between this increasing of cumulative monsoon break days and the observed decrease of seasonal South Asian monsoon rainfall will be the scope of further investigations.

  9. The impact of modern migrations on present-day multi-ethnic Argentina as recorded on the mitochondrial DNA genome

    PubMed Central

    2011-01-01

    Background The genetic background of Argentineans is a mosaic of different continental ancestries. From colonial to present times, the genetic contribution of Europeans and sub-Saharan Africans has superposed to or replaced the indigenous genetic 'stratum'. A sample of 384 individuals representing different Argentinean provinces was collected and genotyped for the first and the second mitochondrial DNA (mtDNA) hypervariable regions, and selectively genotyped for mtDNA SNPs. This data was analyzed together with additional 440 profiles from rural and urban populations plus 304 from Native American Argentineans, all available from the literature. A worldwide database was used for phylogeographic inferences, inter-population comparisons, and admixture analysis. Samples identified as belonging to hg (hg) H2a5 were sequenced for the entire mtDNA genome. Results Phylogenetic and admixture analyses indicate that only half of the Native American component in urban Argentineans might be attributed to the legacy of extinct ancestral Argentineans and that the Spanish genetic contribution is slightly higher than the Italian one. Entire H2a5 genomes linked these Argentinean mtDNAs to the Basque Country and improved the phylogeny of this Basque autochthonous clade. The fingerprint of African slaves in urban Argentinean mtDNAs was low and it can be phylogeographically attributed predominantly to western African. The European component is significantly more prevalent in the Buenos Aires province, the main gate of entrance for Atlantic immigration to Argentina, while the Native American component is larger in North and South Argentina. AMOVA, Principal Component Analysis and hgs/haplotype patterns in Argentina revealed an important level of genetic sub-structure in the country. Conclusions Studies aimed to compare mtDNA frequency profiles from different Argentinean geographical regions (e.g., forensic and case-control studies) should take into account the important genetic

  10. Growth changes in plaice, cod, haddock and saithe in the North Sea: a comparison of (post-)medieval and present-day growth rates based on otolith measurements

    NASA Astrophysics Data System (ADS)

    Bolle, Loes J.; Rijnsdorp, Adriaan D.; van Neer, Wim; Millner, Richard S.; van Leeuwen, Piet I.; Ervynck, Anton; Ayers, Richard; Ongenae, Ellen

    2004-05-01

    Fishing effort has strongly increased in the North Sea since the mid-19th century, causing a substantial reduction in the population size of exploited fish stocks. As fisheries research has developed simultaneously with the industrialisation of the fisheries, our knowledge of population dynamics at low levels of exploitations is limited. Otoliths retrieved from archaeological excavations offer a unique opportunity to study growth rates in the past. This study compares historical and present-day growth rates for four commercially important demersal fish species. A total of 2532 modern otoliths (AD 1984-1999) and 1286 historical otoliths (AD 1200-1925) obtained from archaeological excavations in Belgium and Scotland were analysed. Comparison of the growth patterns between eras revealed a major increase in growth rate of haddock, whereas growth changes were not observed in saithe and only in the smaller size classes of plaice and cod. Comparison of our results with literature data indicates that the observed growth rate changes in plaice and cod occurred within the 20th century. Apparently the onset of industrialised fisheries has not greatly affected the growth of plaice, cod and saithe populations in the North Sea. This result contradicts the expectation of density-dependent limitation of growth during the era of pre-industrialised fishing, but is in agreement with the concentration hypothesis of Beverton (Neth. J. Sea Res. 34 (1995) 1) stating that species which concentrate spatially into nursery grounds during their early life-history may 'saturate' the carrying capacity of the juvenile habitat even though the adult part of the population is not limited by the adult habitat.

  11. Historic, pre-European settlement, and present-day contribution of wild ruminants to enteric methane emissions in the United States.

    PubMed

    Hristov, A N

    2012-04-01

    The objectives of this analysis were to estimate historic (pre-European settlement) enteric CH(4) emissions from wild ruminants in the contiguous United States and compare these with present-day CH(4) emissions from farmed ruminants. The analysis included bison, elk (wapiti), and deer (white-tailed and mule). Wild ruminants such as moose, antelope (pronghorn), caribou, and mountain sheep and goat were not included in the analysis because their natural range is mostly outside the contiguous United States or because they have relatively small population sizes. Data for presettlement and present-day population sizes, animal BW, feed intake, and CH(4) emission factors were adopted from various sources. Present-day CH(4) emissions from livestock were from recent United States Environmental Protection Agency estimates. The most important factor determining CH(4) emissions from wild ruminants in the presettlement period was the size of the bison population. Overall, enteric CH(4) emissions from bison, elk, and deer in the presettlement period were about 86% (assuming bison population size of 50 million) of the current CH(4) emissions from farmed ruminants in the United States. Present-day CH(4) emissions from wild ruminants (bison, elk, and deer) were estimated at 0.28 Tg/yr, or 4.3% of the emissions from domestic ruminants. Due to its population size (estimated at 25 million), the white-tailed deer is the most significant present-day wild ruminant contributor to enteric CH(4) emissions in the contiguous United States. PMID:22178852

  12. Present-day plate motions

    NASA Technical Reports Server (NTRS)

    Minster, J. B.; Jordan, T. H.

    1977-01-01

    A data set comprising 110 spreading rates, 78 transform fault azimuths and 142 earthquake slip vectors was inverted to yield a new instantaneous plate motion model, designated RM2. The mean averaging interval for the relative motion data was reduced to less than 3 My. A detailed comparison of RM2 with angular velocity vectors which best fit the data along individual plate boundaries indicates that RM2 performs close to optimally in most regions, with several notable exceptions. On the other hand, a previous estimate (RM1) failed to satisfy an extensive set of new data collected in the South Atlantic Ocean. It is shown that RM1 incorrectly predicts the plate kinematics in the South Atlantic because the presently available data are inconsistent with the plate geometry assumed in deriving RM1. It is demonstrated that this inconsistency can be remedied by postulating the existence of internal deformation with the Indian plate, although alternate explanations are possible.

  13. Estimations of historical atmospheric mercury concentrations from mercury refining and present-day soil concentrations of total mercury in Huancavelica, Peru.

    PubMed

    Robins, Nicholas A; Hagan, Nicole; Halabi, Susan; Hsu-Kim, Heileen; Gonzales, Ruben Dario Espinoza; Morris, Mark; Woodall, George; Richter, Daniel deB; Heine, Paul; Zhang, Tong; Bacon, Allan; Vandenberg, John

    2012-06-01

    Detailed Spanish records of cinnabar mining and mercury production during the colonial period in Huancavelica, Peru were examined to estimate historical health risks to the community from exposure to elemental mercury (Hg) vapor resulting from cinnabar refining operations. Between 1564 and 1810, nearly 17,000 metric tons of Hg were released to the atmosphere in Huancavelica from Hg production. AERMOD was used with estimated emissions and source characteristics to approximate historic atmospheric concentrations of mercury vapor. Modeled 1-hour and long-term concentrations were compared with present-day inhalation reference values for elemental Hg. Estimated 1-hour maximum concentrations for the entire community exceeded present-day occupational inhalation reference values, while some areas closest to the smelters exceeded present-day emergency response guideline levels. Estimated long-term maximum concentrations for the entire community exceeded the EPA Reference Concentration (RfC) by a factor of 30 to 100, with areas closest to the smelters exceeding the RfC by a factor of 300 to 1000. Based on the estimated historical concentrations of Hg vapor in the community, the study also measured the extent of present-day contamination throughout the community through soil sampling and analysis. Total Hg in soils sampled from 20 locations ranged from 1.75 to 698 mg/kg and three adobe brick samples ranging from 47.4 to 284 mg/kg, consistent with other sites of mercury mining and use. The results of the soil sampling indicate that the present-day population of Huancavelica is exposed to levels of mercury from legacy contamination which is currently among the highest worldwide, consequently placing them at potential risk of adverse health outcomes. PMID:22542225

  14. Post World War II orcharding creates present day DDT-problems in The Sørfjord (Western Norway)--a case study.

    PubMed

    Ruus, Anders; Green, Norman W; Maage, Amund; Amundsen, Carl Einar; Schøyen, Merete; Skei, Jens

    2010-10-01

    The Sørfjord has a long history of agriculture and industry, and environmental monitoring has been conducted for decades, comprising analyses of contaminants in mussel, fish and sediments. DDT was used as an insecticide in orchards surrounding the fjord between World War II and 1970. Since the early 1990 s, elevated concentrations of DDT were found in mussels and fish. Unexpectedly, DDT-concentrations increased towards present day, despite the discontinuation of use. The highest concentrations in mussels (in 2006) corresponded to about two orders of magnitude higher than background. Analyses of sediment core sections also indicated increased input towards present day. Shifts in climatic parameters, as well as increased amounts of soil dissolved organic carbon following a decline in atmospheric sulphate deposition may have contributed to this phenomenon. We warrant the need for increased knowledge of the effects of alterations in variables acting regionally and globally on the disposition of contaminants in ecosystems. PMID:20719343

  15. The influence of mantle viscosity structure and past decadal to millennial-scale ice mass changes on present-day land motion in Greenland.

    NASA Astrophysics Data System (ADS)

    Simpson, Matthew; Wake, Leanne; Milne, Glenn; Huybrechts, Philippe

    2010-05-01

    We show predictions of present-day vertical land motion in Greenland using a recently developed Glacial Isostatic Adjustment (GIA) model, calibrated using both relative sea-level observations and geomorphological contraints on ice extent (Simpson et al., 2009). Predictions from our GIA model are in good agreement to the relatively small number of GPS measurements of absolute vertical motion from south and southwest Greenland. This suggests that our model of ice sheet evolution over the Holocene period is reasonably accurate. The uplift predictions are highly sensitive to variations of upper mantle viscosity; depending on the Earth model adopted different periods of ice loading change dominate the present-day response in particular regions of Greenland. We shall present a suite of results to demonstrate this sensitivity. We also consider the possible influence of more recent changes in the ice sheet by applying a second ice model; specifically, a surface mass balance (SMB) model (Wake et al., 2009), which covers the period 1866 to 2005. Predictions from this model suggest that decadal-scale SMB changes over the last c. 140 years play only a small role in determining the present-day viscous response. However, high rates of peripheral thinning from 1995 to 2005 in the SMB model produce large elastic uplift rates in west and southwest Greenland. Using the same SMB model, we extend our study period to cover the last thousand years (for which there is less accurate climate data) and constrain ice mass changes over this time using new high resolution records of relative sea-level change. Our preliminary findings suggest that century-scale ice mass variation over the last thousand years may contribute significantly to the present-day viscous response. Simpson, M.J.R, Milne, G.A., Huybrechts, P., Long, A.J., 2009. Calibrating a glaciological model of the Greenland ice sheet from the last glacial maximum to present-day using field observations of relative sea level and ice

  16. Lyα-emitting Galaxies at z = 2.1 in ECDF-S: Building Blocks of Typical Present-day Galaxies?

    NASA Astrophysics Data System (ADS)

    Guaita, Lucia; Gawiser, Eric; Padilla, Nelson; Francke, Harold; Bond, Nicholas A.; Gronwall, Caryl; Ciardullo, Robin; Feldmeier, John J.; Sinawa, Shawn; Blanc, Guillermo A.; Virani, Shanil

    2010-05-01

    ) = 11.5+0.4 -0.5, which are among the lowest mass halos yet probed at this redshift. We used the Sheth and Tormen conditional mass function to study the descendants of these LAEs and found that their typical present-day descendants are local galaxies with L* properties, like the Milky Way. Based on observations obtained at Cerro Tololo Inter-American Observatory, a division of the National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation.

  17. Preindustrial to Present-Day Changes in Tropospheric Hydroxyl Radical and Methane Lifetime from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

    NASA Technical Reports Server (NTRS)

    Naik, V.; Voulgarakis, A.; Fiore, A. M.; Horowitz, L. W.; Lamarque, J.-F.; Lin, M.; Prather, M. J.; Young, P. J.; Bergmann, D.; Cameron-Smith, P. J.; Cionni, I.; Collins, W. J.; Dalsoren, S. B.; Doherty, R.; Eyring, V.; Faluvegi, G.; Folberth, G. A.; Josse, B.; Lee, Y. H.; MacKenzie, I. A.; Nagashima, T.; vanNoije, T. P. C.; Plummer, D. A.; Righi, M.; Rumbold, S. T.; Skeie, R.; Shindell, D. T.; Stevenson, D. S.; Strode, S.; Sudo, K.; Szopa, S.; Zeng, G.

    2013-01-01

    We have analysed time-slice simulations from 17 global models, participating in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP), to explore changes in present-day (2000) hydroxyl radical (OH) concentration and methane (CH4) lifetime relative to preindustrial times (1850) and to 1980. A comparison of modeled and observation-derived methane and methyl chloroform lifetimes suggests that the present-day global multi-model mean OH concentration is overestimated by 5 to 10% but is within the range of uncertainties. The models consistently simulate higher OH concentrations in the Northern Hemisphere (NH) compared with the Southern Hemisphere (SH) for the present-day (2000; inter-hemispheric ratios of 1.13 to 1.42), in contrast to observation-based approaches which generally indicate higher OH in the SH although uncertainties are large. Evaluation of simulated carbon monoxide (CO) concentrations, the primary sink for OH, against ground-based and satellite observations suggests low biases in the NH that may contribute to the high north–south OH asymmetry in the models. The models vary widely in their regional distribution of present-day OH concentrations (up to 34%). Despite large regional changes, the multi-model global mean (mass-weighted) OH concentration changes little over the past 150 yr, due to concurrent increases in factors that enhance OH (humidity, tropospheric ozone, nitrogen oxide (NOx) emissions, and UV radiation due to decreases in stratospheric ozone), compensated by increases in OH sinks (methane abundance, carbon monoxide and non-methane volatile organic carbon (NMVOC) emissions). The large inter-model diversity in the sign and magnitude of preindustrial to present-day OH changes (ranging from a decrease of 12.7% to an increase of 14.6%) indicate that uncertainty remains in our understanding of the long-term trends in OH and methane lifetime. We show that this diversity is largely explained by the different ratio of the

  18. Estimating heat stress from climate-based indicators: present-day biases and future spreads in the CMIP5 global climate model ensemble

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Ducharne, A.; Sultan, B.; Braconnot, P.; Vautard, R.

    2015-08-01

    The increased exposure of human populations to heat stress is one of the likely consequences of global warming, and it has detrimental effects on health and labor capacity. Here, we consider the evolution of heat stress under climate change using 21 general circulation models (GCMs). Three heat stress indicators, based on both temperature and humidity conditions, are used to investigate present-day model biases and spreads in future climate projections. Present day estimates of heat stress indicators from observational data shows that humid tropical areas tend to experience more frequent heat stress than other regions do, with a total frequency of heat stress 250-300 d yr-1. The most severe heat stress is found in the Sahel and south India. Present-day GCM simulations tend to underestimate heat stress over the tropics due to dry and cold model biases. The model based estimates are in better agreement with observation in mid to high latitudes, but this is due to compensating errors in humidity and temperature. The severity of heat stress is projected to increase by the end of the century under climate change scenario RCP8.5, reaching unprecedented levels in some regions compared with observations. An analysis of the different factors contributing to the total spread of projected heat stress shows that spread is primarily driven by the choice of GCMs rather than the choice of indicators, even when the simulated indicators are bias-corrected. This supports the utility of the multi-model ensemble approach to assess the impacts of climate change on heat stress.

  19. How significant are Phaeocystis colony blooms in the present-day Southern North Sea compared to a reconstructed pristine situation: a model study

    NASA Astrophysics Data System (ADS)

    Lancelot, Christiane; Passy, Paul; Gypens, Nathalie

    2014-05-01

    We performed simulations with the existing MIRO&CO 3D ecological model to assess the present-day magnitude and geographical extent of undesirable Phaeocystis colony blooms in the Southern Bight of the North Sea (SNS) receiving nutrient inputs by large European rivers. The criterion of 4 106 Phaeocystis cells L-1 of Lancelot et al. (2009) is used to scale the presence of undesirable bloom. These simulations are compared with a reconstructed pristine SNS ecosystem making use of nutrient inputs calculated by the Seneque/Riverstrahler model of the river system when all human activities on the watershed have been erased. Interannual variability is considered by performing model runs for two contrasted meteorological years: wet (2001) and dry (2005). Results show a large excess of nitrogen (N) and phosphorus (P) delivery to the SNS of i.e. respectively 12 and 5 times the pristine situation. In contrast the total silicon (Si) delivery is decreased with respect to natural conditions although not shown for every river. Qualitatively, pristine river inputs are shown a large excess Si for pristine but excess N for both 2001 and 2005, when compared to the agreed N, P and Si requirement of coastal diatoms. Responding to the river nutrient inputs, either natural or of anthropogenic origin, phytoplankton blooms are simulated in the vicinity of the river mouths, especially in the eastern SNS receiving 78-98% of the direct river inputs and where nutrients cumulate along a SW-NE gradient, allowing the bloom to form a wide ribbon parallel to the coast. A short time-delay is simulated between the western and eastern SNS due to light limitation imposed by the large sediment inputs discharged by the Thames. A spring diatom-Phaeocystis succession is simulated for both present-day and pristine. Pristine diatoms dominate the bulk of the phytoplankton community; Phaeocystis colonies develop in the whole domain, especially in the Thames and Scheldt river plume though their biomass remains

  20. The origin of the asymmetry in the Iceland hotspot along the Mid-Atlantic Ridge from continental breakup to present-day

    NASA Astrophysics Data System (ADS)

    Howell, Samuel M.; Ito, Garrett; Breivik, Asbjørn J.; Rai, Abhishek; Mjelde, Rolf; Hanan, Barry; Sayit, Kaan; Vogt, Peter

    2014-04-01

    The Iceland hotspot has profoundly influenced the creation of oceanic crust throughout the North Atlantic basin. Enigmatically, the geographic extent of the hotspot influence along the Mid-Atlantic Ridge has been asymmetric for most of the spreading history. This asymmetry is evident in crustal thickness along the present-day ridge system and anomalously shallow seafloor of ages ∼49-25 Ma created at the Reykjanes Ridge (RR), SSW of the hotspot center, compared to deeper seafloor created by the now-extinct Aegir Ridge (AR) the same distance NE of the hotspot center. The cause of this asymmetry is explored with 3-D numerical models that simulate a mantle plume interacting with the ridge system using realistic ridge geometries and spreading rates that evolve from continental breakup to present-day. The models predict plume-influence to be symmetric at continental breakup, then to rapidly contract along the ridges, resulting in widely influenced margins next to uninfluenced oceanic crust. After this initial stage, varying degrees of asymmetry along the mature ridge segments are predicted. Models in which the lithosphere is created by the stiffening of the mantle due to the extraction of water near the base of the melting zone predict a moderate amount of asymmetry; the plume expands NE along the AR ∼70-80% as far as it expands SSW along the RR. Without dehydration stiffening, the lithosphere corresponds to the near-surface, cool, thermal boundary layer; in these cases, the plume is predicted to be even more asymmetric, expanding only 40-50% as far along the AR as it does along the RR. Estimates of asymmetry and seismically measured crustal thicknesses are best explained by model predictions of an Iceland plume volume flux of ∼100-200 m/s, and a lithosphere controlled by a rheology in which dehydration stiffens the mantle, but to a lesser degree than simulated here. The asymmetry of influence along the present-day ridge system is predicted to be a transient

  1. Structural Evolution of the India-Arabia Plate Boundary from Miocene to Present-Day (NW Indian Ocean) and Comparison with the Dead Sea Fault (Eastern Mediterranean Sea).

    NASA Astrophysics Data System (ADS)

    Rodriguez, M.; Huchon, P.; Chamot Rooke, N.; Fournier, M.; Delescluse, M.; Ben Avraham, Z.; Ten Brink, U. S.

    2014-12-01

    Arabia is bounded by the Dead Sea Transform (DST) to the west and by the Owen Fracture Zone (OFZ) to the east. These present-day major strike-slip fault systems activated during the Plio-Pleistocene, which contrasts with the age of inception of strike-slip motion, assumed to begin around 13-18 Ma for the DST and around 20 Ma at the edge of the Owen-Murray Ridge (OMR) for the India-Arabia plate boundary. This discrepancy between the age of the active strike-slip systems and the age of inception of strike-slip motion raises the question of the kinematic driver for the transition between successive generations of strike-slip faults. Using a recent mutibeam and seismic dataset crossing the OFZ and the OMR, we provide a new geodynamic framework for the Miocene to present-day structural evolution of the India-Arabia plate boundary, and highlight some similarities with the structural evolution of the DST. We first document a Late Miocene episode of uplift of the OMR uplift along the Miocene India-Arabia plate boundary. The onset of this uplift is coeval with a plate reorganization event marked by the onset of intra-plate deformation in the Central Indian Ocean. The OFZ emplaced around 3 Ma, with major pull-apart basins opening (20°N Basin, Dalrymple Trough) dated at 2.4 Ma by far-field correlation with ODP Sites. The opening of pull-apart basins is coeval with the last structural reorganization of the Makran accretionnary wedge, marked by the regional M-unconformity, and with a major intensification of the Indian monsoon. A Late Miocene episode of folding is also recognized at the Lebanon ranges prior to the onset of the present-day DST, which occurred in the Late Pliocene-Early Pleistocene. The similarities between the geological history of the India-Arabia plate boundary and the DST in the Late Miocene and the Late Pliocene-Early Pleistocene suggest that both plate boundaries recorded the same kinematic changes. Late Miocene (i.e. Tortonian) deformation is widely

  2. Evaluating CMIP5 ocean biogeochemistry and Southern Ocean carbon uptake using atmospheric potential oxygen: Present-day performance and future projection

    NASA Astrophysics Data System (ADS)

    Nevison, C. D.; Manizza, M.; Keeling, R. F.; Stephens, B. B.; Bent, J. D.; Dunne, J.; Ilyina, T.; Long, M.; Resplandy, L.; Tjiputra, J.; Yukimoto, S.

    2016-03-01

    Observed seasonal cycles in atmospheric potential oxygen (APO ~ O2 + 1.1 CO2) were used to evaluate eight ocean biogeochemistry models from the Coupled Model Intercomparison Project (CMIP5). Model APO seasonal cycles were computed from the CMIP5 air-sea O2 and CO2 fluxes and compared to observations at three Southern Hemisphere monitoring sites. Four of the models captured either the observed APO seasonal amplitude or phasing relatively well, while the other four did not. Many models had an unrealistic seasonal phasing or amplitude of the CO2 flux, which in turn influenced APO. By 2100 under RCP8.5, the models projected little change in the O2 component of APO but large changes in the seasonality of the CO2 component associated with ocean acidification. The models with poorer performance on present-day APO tended to project larger net carbon uptake in the Southern Ocean, both today and in 2100.

  3. Quantitative Study of the Present-Day Climate of the Middle Tennessee Elk Watershed Area From Global and Regional Climate Model Simulations

    NASA Astrophysics Data System (ADS)

    Kebede, G.

    2015-12-01

    As part of a wider hydro climatic modeling research, we studied the spatial and temporal variability of precipitation and temperature over the Middle Tennessee Elk watershed and its environs using regional climate model simulations over the past 30 years. Three sets of simulations with the Hadley Center's regional climate model (PRECIS) were carried out for the present day climate (1980-2010) at a resolution of 25km covering the southeastern U.S. These three sets simulations are driven by lateral boundary conditions taken from ERA-Interim reanalysis, and two global climate models (HadCM3 and ECHAM5) respectively. For validation, high resolution observed daily data sets from North American Land-Data Assimilation System (NLDAS) and Climate Research Unit, CRU data are used. Preliminary results show that the spatial distribution of the present-day seasonal mean rainfall and temperature, simulated by PRECIS, are not only consistent with NLDAS and CRU but also captured fine scale spatial structures that are missing in the global model simulations due to their coarse resolution. In addition, the annual cycle and intera-anual variability, particularly that of temperature, are reasonably well reproduced by the PRECIS. When comparing the PRECIS simulations with the driving GCMs, PRECIS is sensitive to the choice of the driving GCM, suggesting a careful selection of driving GCM based on the current climate performance for the use of future climate impact assessment. Quantitative understanding of the climate system and better estimation of the fresh water balance over the Middle Tennessee Elk watershed is a vital corner stone for a sustainable economic growth of the region over the coming decades.

  4. Seismological Structure of the 1.8Ga Trans-Hudson Orogen of North America and its affinity to present-day Tibet

    NASA Astrophysics Data System (ADS)

    Gilligan, A.; Bastow, I. D.; Darbyshire, F. A.

    2015-12-01

    How tectonic processes operated and changed through the Precambrian is debated: what was the nature and scale of orogenic events and were they different on the younger, hotter, more ductile Earth? The geology of northern Hudson Bay records the Paleoproterozoic collision between the Western Churchill and Superior plates: the 1.8Ga Trans-Hudson Orogeny (THO) and is thus an ideal study locale to address this issue. It has been suggested, primarily on the strength of traditional field geology, that the THO was comparable in scale and style to the present-day Himalayan-Karakoram-Tibet Orogen (HKTO). However, understanding of the deep crustal architecture of the THO, and how it compares to the evolving HKTO is presently lacking. Through joint inversion of teleseismic receiver functions and surface wave data, we obtain new Moho depth estimates and shear velocity models for the crust and upper mantle. Archean crust in the Rae, Hearne and Churchill domains is thin and structurally simple, with a sharp Moho; upper crustal wavespeed variations are readily attributed to post-formation events. However, the Paleoproterozoic Quebec-Baffin segment of the THO has a deeper Moho and more complex crustal structure. Our observations are strikingly similar to recent models, computed using the same methods, of the HKTO lithosphere, where deformation also extends >400km beyond the collision front. On the strength of Moho character, present-day crustal thickness, and metamorphic grade, we thus propose that southern Baffin experienced uplift of a similar magnitude and spatial extent to the Himalayas during the Paleoproterozoic Trans-Hudson Orogeny.

  5. Estimating historical atmospheric mercury concentrations from silver mining and their legacies in present-day surface soil in Potosí, Bolivia

    NASA Astrophysics Data System (ADS)

    Hagan, Nicole; Robins, Nicholas; Hsu-Kim, Heileen; Halabi, Susan; Morris, Mark; Woodall, George; Zhang, Tong; Bacon, Allan; Richter, Daniel De B.; Vandenberg, John

    2011-12-01

    Detailed Spanish records of mercury use and silver production during the colonial period in Potosí, Bolivia were evaluated to estimate atmospheric emissions of mercury from silver smelting. Mercury was used in the silver production process in Potosí and nearly 32,000 metric tons of mercury were released to the environment. AERMOD was used in combination with the estimated emissions to approximate historical air concentrations of mercury from colonial mining operations during 1715, a year of relatively low silver production. Source characteristics were selected from archival documents, colonial maps and images of silver smelters in Potosí and a base case of input parameters was selected. Input parameters were varied to understand the sensitivity of the model to each parameter. Modeled maximum 1-h concentrations were most sensitive to stack height and diameter, whereas an index of community exposure was relatively insensitive to uncertainty in input parameters. Modeled 1-h and long-term concentrations were compared to inhalation reference values for elemental mercury vapor. Estimated 1-h maximum concentrations within 500 m of the silver smelters consistently exceeded present-day occupational inhalation reference values. Additionally, the entire community was estimated to have been exposed to levels of mercury vapor that exceed present-day acute inhalation reference values for the general public. Estimated long-term maximum concentrations of mercury were predicted to substantially exceed the EPA Reference Concentration for areas within 600 m of the silver smelters. A concentration gradient predicted by AERMOD was used to select soil sampling locations along transects in Potosí. Total mercury in soils ranged from 0.105 to 155 mg kg-1, among the highest levels reported for surface soils in the scientific literature. The correlation between estimated air concentrations and measured soil concentrations will guide future research to determine the extent to which the

  6. Present-day cosmic abundances. A comprehensive study of nearby early B-type stars and implications for stellar and Galactic evolution and interstellar dust models

    NASA Astrophysics Data System (ADS)

    Nieva, M.-F.; Przybilla, N.

    2012-03-01

    Context. Early B-type stars are ideal indicators for present-day cosmic abundances since they preserve their pristine abundances and typically do not migrate far beyond their birth environments over their short lifetimes, in contrast to older stars like the Sun. They are also unaffected by depletion onto dust grains, unlike the cold/warm interstellar medium (ISM) or H ii regions. Aims: A carefully selected sample of early B-type stars in OB associations and the field within the solar neighbourhood is studied comprehensively. Quantitative spectroscopy is used to characterise their atmospheric properties in a self-consistent way. Present-day abundances for the astrophysically most interesting chemical elements are derived in order to investigate whether a present-day cosmic abundance standard can be established. Methods: High-resolution and high-S/N FOCES, FEROS and ELODIE spectra of well-studied sharp-lined early B-type stars are analysed in non-LTE. Line-profile fits based on extensive model grids and an iterative analysis methodology are used to constrain stellar parameters and elemental abundances at high accuracy and precision. Atmospheric parameters are derived from the simultaneous establishment of independent indicators, from multiple ionization equilibria and the Stark-broadened hydrogen Balmer lines, and they are confirmed by reproduction of the stars' global spectral energy distributions. Results: Effective temperatures are constrained to 1-2% and surface gravities to less than 15% uncertainty, along with accurate rotational, micro- and macroturbulence velocities. Good agreement of the resulting spectroscopic parallaxes with those from the new reduction of the Hipparcos catalogue is obtained. Absolute values for abundances of He, C, N, O, Ne, Mg, Si and Fe are determined to better than 25% uncertainty. The synthetic spectra match the observations reliably over almost the entire visual spectral range. Three sample stars, γ Ori, o Per and θ1 Ori D, are

  7. The Impact of LEP G-2548A and LEPR Gln223Arg Polymorphisms on Adiposity, Leptin, and Leptin-Receptor Serum Levels in a Mexican Mestizo Population

    PubMed Central

    Chavarria-Avila, Efraín; Gomez-Bañuelos, Eduardo; Ruiz-Quezada, Sandra-Luz; Castro-Albarran, Jorge; Sánchez-López, Lizeth; Martín-Marquez, Beatriz Teresita; Navarro-Hernández, Rosa-Elena

    2015-01-01

    The polymorphisms in leptin (LEP G-2548A) and leptin-receptor (LEPR Gln223Arg) seem to influence obesity and lipid metabolism among others. The aim of this study was to investigate the effect of these polymorphisms on adiposity, leptin (sLeptin), and leptin-receptor (sLeptin-receptor) serum concentrations as well as inflammation markers. We included 382 adults originally from Western Mexico. They were genotyped by PCR-RFLP. Obese individuals showed higher sLeptin (58.2 ± 31.35 ng/mL) but lower sLeptin-receptor (12.6 ± 3.74 ng/mL) levels than normal weight ones (17.6 ± 14.62 ng/mL, 17.4 ± 4.62 ng/mL, resp.), P < 0.001. Obese subjects carriers of Arg/Arg genotype had more (P = 0.016) sLeptin-receptor (14.7 ± 4.96 ng/mL) and less (P = 0.004) sLeptin (44.0 ± 28.12 ng/mL) levels than Gln/Gln genotype (11.0 ± 2.92 ng/mL, 80.3 ± 33.24 ng/mL, resp.). Body fat mass was lower (P from 0.003 to 0.045) for A/A (36.5% ± 6.80) or Arg/Arg (36.8% ± 6.82) genotypes with respect to G/G (41.3% ± 5.52) and G/A (41.6% ± 5.61) or Gln/Gln (43.7% ± 4.74) and Gln/Arg (41.0% ± 5.52) genotypes carriers. Our results suggest that LEP -2548A and LEPR 223Arg could be genetic markers of less body fat mass accumulation in obese subjects from Western Mexico. PMID:26064921

  8. Population data of 24 STRs in Mexican-Mestizo population from Monterrey, Nuevo Leon (Northeast, Mexico) based on Powerplex(®) Fusion and GlobalFiler(®) kits.

    PubMed

    Ramos-González, Benito; Aguilar-Velázquez, José Alonso; Chávez-Briones, María de Lourdes; Delgado-Chavarría, Juan Ramón; Alfaro-Lopez, Elizabeth; Rangel-Villalobos, Héctor

    2016-03-01

    The STR loci included into new commercial human identification kits compels geneticists estimating forensic parameters for interpretation purposes in forensic casework. Therefore, we studied for the first time in Mexico the GlobalFiler(®) and Powerplex(®) Fusion systems in 326 and 682 unrelated individuals, respectively. These individuals are resident of the Monterrey City of the Nuevo Leon state (Northeast, Mexico). Population data from 23 autosomal STRs and the Y-STR locus DYS391 are reported and compared against available STR data from American ethnic groups and the unique Mexican population studied with Powerplex(®) Fusion. PMID:26747399

  9. Differential responses of calcifying and non-calcifying epibionts of a brown macroalga to present-day and future upwelling pCO2.

    PubMed

    Saderne, Vincent; Wahl, Martin

    2013-01-01

    Seaweeds are key species of the Baltic Sea benthic ecosystems. They are the substratum of numerous fouling epibionts like bryozoans and tubeworms. Several of these epibionts bear calcified structures and could be impacted by the high pCO2 events of the late summer upwellings in the Baltic nearshores. Those events are expected to increase in strength and duration with global change and ocean acidification. If calcifying epibionts are impacted by transient acidification as driven by upwelling events, their increasing prevalence could cause a shift of the fouling communities toward fleshy species. The aim of the present study was to test the sensitivity of selected seaweed macrofoulers to transient elevation of pCO2 in their natural microenvironment, i.e. the boundary layer covering the thallus surface of brown seaweeds. Fragments of the macroalga Fucus serratus bearing an epibiotic community composed of the calcifiers Spirorbis spirorbis (Annelida) and Electra pilosa (Bryozoa) and the non-calcifier Alcyonidium hirsutum (Bryozoa) were maintained for 30 days under three pCO2 conditions: natural 460 ± 59 µatm, present-day upwelling1193 ± 166 µatm and future upwelling 3150 ± 446 µatm. Only the highest pCO2 caused a significant reduction of growth rates and settlement of S. spirorbis individuals. Additionally, S. spirorbis settled juveniles exhibited enhanced calcification of 40% during daylight hours compared to dark hours, possibly reflecting a day-night alternation of an acidification-modulating effect by algal photosynthesis as opposed to an acidification-enhancing effect of algal respiration. E. pilosa colonies showed significantly increased growth rates at intermediate pCO2 (1193 µatm) but no response to higher pCO2. No effect of acidification on A. hirsutum colonies growth rates was observed. The results suggest a remarkable resistance of the algal macro-epibionts to levels of acidification occurring at present day upwellings in the Baltic. Only extreme

  10. Human responses to eruptions of Etna (Sicily) during the late-Pre-Industrial Era and their implications for present-day disaster planning

    NASA Astrophysics Data System (ADS)

    Chester, David K.; Duncan, Angus M.; Sangster, Heather

    2012-05-01

    This paper summarises: the characteristics of eruptions that occurred between 1792/3 and 1923; the ways in which human responses evolved during the period and the lessons this history holds for the management of present-day volcanic and volcano-related disasters. People responded to eruptions at three levels: as members of a family and extended family; through the mutual support of a village or larger settlement and as citizens of the State. During the study period and with the exception of limited financial aid and preservation of law and order, the State was a minor player in responding to eruptions. Families and extended families provided shelter, accommodation and often alternative agricultural employment; whilst supportive villages communities displayed a well developed tendency to learn from experience (e.g. innovating techniques to bring land back into cultivation and avoiding the risks of phreatic activity as lava encountered water and saturated ground) and providing labour to enable household chattels and agricultural crops to be salvaged from land threatened with lava incursion. Eruptions were widely believed to be 'Acts of God', with divine punishment frequently being invoked as a primary cause of human suffering. Elaborate rituals of propitiation were performed to appease a supposed angry God, but this world-view did not produce a fatalistic attitude amongst the population preventing people from coping with disasters in a generally effective manner. Despite present day emergencies being handled by the State and its agencies, some features of nineteenth century responses remain in evidence, including salvaging all that may be easily removed from a building and/or agricultural holding, and explanations of disaster which are theistic in character. Lessons from eruptions that occurred between 1792/3 to 1923 are that the former should be encouraged, whilst the latter does not prevent people acting to preserve life and property or obeying the authorities

  11. UV-B absorbing compounds in present-day and fossil pollen, spores, cuticles, seed coats and wood: evaluation of a proxy for solar UV radiation.

    PubMed

    Rozema, J; Blokker, P; Mayoral Fuertes, M A; Broekman, R

    2009-09-01

    UV-B absorbing compounds (UACs) in present-day and fossil pollen, spores, cuticles, seed coats and wood have been evaluated as a proxy for past UV. This proxy may not only provide information on variation of stratospheric ozone and solar UV in the period preceding and during the Antarctic ozone hole (1974-present day), but also on the development and variation of the stratospheric ozone layer and solar surface UV during the evolution of life on Earth. Sporopollenin and cutin are highly resistant biopolymers, preserving well in the geological record and contain the phenolic acids p-coumaric (pCA) and ferulic acid (FA). pCA and FA represent a good perspective for a plant-based proxy for past surface UV radiation since they are induced by solar UV-B via the phenylpropanoid pathway (PPP). UV-B absorption by these monomers in the wall of pollen and spores and in cuticles may prevent damage to the cellular metabolism. Increased pCA and FA in pollen of Vicia faba exposed to enhanced UV-B was found in greenhouse experiments. Further correlative evidence comes from UV-absorbing compounds in spores from 1960-2000 comparing exposure of land plants (Lycopodium species) to solar UV before and during ozone depletion and comparing plants from Antarctica (severe ozone depletion), Arctic, and other latitudes with less or negligible ozone depletion. Wood-derived compounds guaiacyl (G), syringyl (S), and p-hydroxyphenyl (P) are produced via the PPP. The proportions of P, G, and S in the lignin differ between various plant groups (e.g. dicotyledons/monocotyledons, gymnosperms/angiosperms). It is hypothesized that this lignin composition and derived physiological and physical properties of lignin (such as tree-ring wood density) has potential as a proxy for palaeo-UV climate. However validation by exposure of trees to enhanced UV is lacking. pCA and FA also form part of cutin polymers and are found in extant and fossil Ginkgo leaf cuticles as shown by thermally-assisted hydrolysis and

  12. Present-Day Strain Transfer Across the Yakutat Collision in SW Yukon - SE Alaska: The Death of the Southern Denali Fault?

    NASA Astrophysics Data System (ADS)

    Marechal, A.; Mazzotti, S.; Ritz, J. F.; Ferry, M. A.; Freymueller, J. T.

    2014-12-01

    In SW Yukon-SE Alaska, the present-day Pacific-North America relative motion is highly oblique to the main plate boundary, resulting in strong strain-partitioning tectonics that link the Aleutian subduction to the west to Queen Charlotte transform to the south. This transition region is also the site of present-day orogeny and accretion of the Yakutat Terrane to the Northern Cordillera. Multiple datasets (GPS, geomorphology, seismicity) are integrated to characterize and quantify strain patterns, with particular emphasis on strain partitioning between strike-slip and shortening deformation. New GPS data straddling the main faults (Denali, Totschunda, Fairweather) indicate that, south of the collision corner, 95% of the Pacific-North America strike-slip motion is accommodated on the plate-boundary Fairweather Fault, leaving near-zero motion on the Denali Fault only ~100 km inboard. In contrast, the fault-perpendicular component is strongly distributed between shortening offshore, in the orogen, and inland outward motion. In the region of highest convergence obliquity, GPS data show a diffuse indentor-like deformation, with strong along-strike variations of the main fault slip rates. Preliminary results of a regional geomorphology study give further information about the Denali Fault, where previous data suggest a velocity decrease from 8 mm/yr (Matmon et al.,2006) to 4 mm/yr (Seitz et al., 2010). A high resolution DEM processed from Pleiades satellite imagery highlights a significant vertical component on the Denali Fault and very little to no strike-slip movement in its southern part. Metric-scale displacements are measured along the "inactive" part of the fault showing recent vertical deformation since the Last Glacial Maximum (~20 kyrs ago). In contrast, significant dextral offsets on post-LGM structures are measured on the southern Totschunda Fault. Ongoing datation of geomorphological markers (Be10, OSL) will give us new slip-rate estimates along the southern

  13. Pedological constraints controlling the occurrence of mire plant bioindicators from north Atlantic formerly frozen soils to present-day Mediterranean sandy wet habitats

    NASA Astrophysics Data System (ADS)

    Geraldes, Miguel; da Conceição Freitas, Maria; Cruces, Anabela; Andrade, César; Oliva, Marc; Neto, Carlos; do Rosário Carvalho, Maria

    2013-04-01

    Unlocking the palaeoenvironmental context, in which present peaty sols in former cold regions of Western Europe, may contribute to the understanding of the actual distribution of three acid-soil vascular plants. Likewise can the role played by similar soil and water conditions (due to other context) be the key to explain their expansion further South. The present work aims to compare the origins and traits of such similar ecotons and to verify how these vascular plants can be use as bioindicators for the presence of peaty soils, picking the proper variables and their geographical variation fits in the Ecological amplitude of the species. The soil and the water are the two compartmeents in which some of the variables might control the present-day distributions of the three taxa. The reactions of a certain number of soil samples carefully taken at shallow depths in the profiles of peaty soils of mires or peat-reach habitats, which cover more than fifty tiny to moderate sampled areas of western Europe (Atlantic Façade and the Iberian Península) and Northwestern Morocco, are being determined in the laboratory of the Geology Department of the University of Lisbon, where some characteristic mire-akin plant taxa have their southernmost range, somewhat in disharmony with meso-to thermomediterranean climates (Rivas Martínez, Global Bioclimatics). Two samples (A and B) were collected per site, the A corresponding to the presence of one of the three bioindicators, the B dug where the species ceases to be present. The present soil processes in the northern part of this sampling is in many cases related to a cold region, glaciated or under periglacial conditions during LGM, but the sedimentary and hydrologic analogies further south might help to explain how euro-siberian species can migrate that long and withstand present-day warmer and drier climates. The pH values of samples were plotted against the depth, and curves, correlations and other possible relationships will be

  14. Differential Responses of Calcifying and Non-Calcifying Epibionts of a Brown Macroalga to Present-Day and Future Upwelling pCO2

    PubMed Central

    Saderne, Vincent; Wahl, Martin

    2013-01-01

    Seaweeds are key species of the Baltic Sea benthic ecosystems. They are the substratum of numerous fouling epibionts like bryozoans and tubeworms. Several of these epibionts bear calcified structures and could be impacted by the high pCO2 events of the late summer upwellings in the Baltic nearshores. Those events are expected to increase in strength and duration with global change and ocean acidification. If calcifying epibionts are impacted by transient acidification as driven by upwelling events, their increasing prevalence could cause a shift of the fouling communities toward fleshy species. The aim of the present study was to test the sensitivity of selected seaweed macrofoulers to transient elevation of pCO2 in their natural microenvironment, i.e. the boundary layer covering the thallus surface of brown seaweeds. Fragments of the macroalga Fucus serratus bearing an epibiotic community composed of the calcifiers Spirorbis spirorbis (Annelida) and Electra pilosa (Bryozoa) and the non-calcifier Alcyonidium hirsutum (Bryozoa) were maintained for 30 days under three pCO2 conditions: natural 460±59 µatm, present-day upwelling1193±166 µatm and future upwelling 3150±446 µatm. Only the highest pCO2 caused a significant reduction of growth rates and settlement of S. spirorbis individuals. Additionally, S. spirorbis settled juveniles exhibited enhanced calcification of 40% during daylight hours compared to dark hours, possibly reflecting a day-night alternation of an acidification-modulating effect by algal photosynthesis as opposed to an acidification-enhancing effect of algal respiration. E. pilosa colonies showed significantly increased growth rates at intermediate pCO2 (1193 µatm) but no response to higher pCO2. No effect of acidification on A. hirsutum colonies growth rates was observed. The results suggest a remarkable resistance of the algal macro-epibionts to levels of acidification occurring at present day upwellings in the Baltic. Only extreme future

  15. Determination of the root-mean-square radius of the deuteron from present-day experimental data on neutron-proton scattering

    SciTech Connect

    Babenko, V. A.; Petrov, N. M.

    2008-10-15

    The correlation between the root-mean-square matter radius of the deuteron, r{sub m}, and its effective radius, {rho}, is investigated. A parabolic relationship between these two quantities makes it possible to determine the root-mean-square radius r{sub m} to within 0.01% if the effective radius {rho} is known. The matter (r{sub m}), structural (r{sub d}), and charge (r{sub ch}) radii of the deuteron are found with the aid of modern experimental results for phase shifts from the SAID nucleon-nucleon database, and their values are fully consistent with their counterparts deduced by using the experimental value of the effective deuteron radius due to Borbely and his coauthors. The charge-radius value of 2.124(6) fm, which was obtained with the aid of the SAID nucleon-nucleon database, and the charge-radius value of 2.126(12) fm, which was obtained with the aid of the experimental value of the effective radius {rho}, are in very good agreement with the present-day chargeradius value of 2.128(11) fm, which was deduced by Sick and Trautmann by processing world-average experimental data on elastic electron scattering by deuterons with allowance for Coulomb distortions.

  16. Anti-HIV drug development: structural features and limitations of present day drugs and future challenges in the successful HIV/AIDS treatment.

    PubMed

    Kumari, Garima; Singh, Ramendra K

    2013-01-01

    Acquired Immune Deficiency Syndrome (AIDS), an immuno-compromized condition, a sequel to untreated human immunodeficiency virus (HIV) infection, inviting several life-threatening diseases, has become one of the most fatal disorders in the recent past because of HIV strain variance due to mutations, passive latency and reservoirs helping in replenishing and reviving the HIV-1 proviral DNA. Scientific efforts have led to the discovery of several effective drugs against HIV and lowered the morbidity and mortality all over the world. However, despite availability of a good number of anti-HIV drugs, the problem, for the foreseeable reasons, stands out as the most chronic disease due to the less tolerability and low accessibility of drugs, life-long expensive treatment, and above all, the emergence of drug resistant viral strains. This review dwells upon HIV infection and its proliferation inside the host system, drug targets, different types of drugs, their structural features and mode of interaction with viral targets and drug regimens. It further focuses on topics of latest interest regarding drug development, fixed dose combinations (FDCs), the limitations of present day drugs with their structural features along with their pharmacodynamics, pharmacokinetics and pharmacogenomics and the challenges in finding a permanent cure for HIV/AIDS. PMID:23092282

  17. Sulfur Dioxide and the Production of Sulfuric Acid on Present-Day and Early Mars: Implications for the Lack of Detected Carbonates on the Surface

    NASA Technical Reports Server (NTRS)

    Levine, Joel S.; Summers, Michael E.

    2008-01-01

    In the early history of Mars, volcanic activity associated with the formation of the Tharsis ridge produced a very large amount of atmospheric SO2--on the order of a bar of atmospheric SO2. In the present-day atmosphere of Mars, the lifetime of SO2 is relatively short with a lifetime of less than a day. The short lifetime of SO2 in the present Mars atmosphere makes the production of significant levels of H2SO4 very difficult since the SO2 may be destroyed by various chemical and photochemical processes before the SO2 can be converted to H2SO4. However, photochemical calculations performed and described here, indicate that enhanced atmospheric levels of CO2 in the early atmosphere of Mars resulted in a significantly enhanced atmospheric lifetime for SO2 up to several years. With a significantly enhanced atmospheric lifetime, SO2 could readily form large amounts of H2SO4, which precipitated out of the atmosphere in the form of droplets. The precipitated H2SO4 then reacted with potential surface carbonates, destroying the carbonates and resulting in the abundant and widespread distribution of sulfates on the surface of Mars as detected by recent Mars missions.

  18. Investigations of potential microbial methanogenic and carbon monoxide utilization pathways in ultra-basic reducing springs associated with present-day continental serpentinization: the Tablelands, NL, CAN

    PubMed Central

    Morrill, Penny L.; Brazelton, William J.; Kohl, Lukas; Rietze, Amanda; Miles, Sarah M.; Kavanagh, Heidi; Schrenk, Matthew O.; Ziegler, Susan E.; Lang, Susan Q.

    2014-01-01

    Ultra-basic reducing springs at continental sites of serpentinization act as portals into the biogeochemistry of a subsurface environment with H2 and CH4 present. Very little, however, is known about the carbon substrate utilization, energy sources, and metabolic pathways of the microorganisms that live in this ultra-basic environment. The potential for microbial methanogenesis with bicarbonate, formate, acetate, and propionate precursors and carbon monoxide (CO) utilization pathways were tested in laboratory experiments by adding substrates to water and sediment from the Tablelands, NL, CAD, a site of present-day continental serpentinization. Microbial methanogenesis was not observed after bicarbonate, formate, acetate, or propionate addition. CO was consumed in the live experiments but not in the killed controls and the residual CO in the live experiments became enriched in 13C. The average isotopic enrichment factor resulting from this microbial utilization of CO was estimated to be 11.2 ± 0.2‰. Phospholipid fatty acid concentrations and δ13C values suggest limited incorporation of carbon from CO into microbial lipids. This indicates that in our experiments, CO was used primarily as an energy source, but not for biomass growth. Environmental DNA sequencing of spring fluids collected at the same time as the addition experiments yielded a large proportion of Hydrogenophaga-related sequences, which is consistent with previous metagenomic data indicating the potential for these taxa to utilize CO. PMID:25431571

  19. Human reponses to historical eruptions of Etna (Sicily) from 1600 to present and their implications for present-day disaster planning

    NASA Astrophysics Data System (ADS)

    Sangster, H.; Chester, D. K.; Duncan, A. M.

    2012-04-01

    Mount Etna in northeastern Sicily (Italy) rises to over 3000 m, covers an area of ca.1750 km2 and is the most active volcano in Europe. Observations of Etna by literate observers stretch back to the classical era and one of the earliest references to an eruption of Etna was by Pindar in his Pythian Odes, to the event of ca. 474-479 B.C. The history of its activity has been reconstructed by scholars up to the present day and records of eruptions are reasonably complete from the early fifteenth century, reliable from 1669, and document the threats and destruction to human settlements and livelihoods. Effusive and explosive activity has occurred continually throughout the historical period and eruptions of Mount Etna have presented numerous eruption styles, from persistent central crater activity, to periodic flank eruptions. From 1600 to 1669 the activity of Etna was characterised by a high volumetric output of lava with a mean eruption rate of 1.19 m3s-1, this was followed by a pause from flank eruptions and the re-establishment of significant activity from the middle of the eighteenth century. After 1750 the output of lava by flank eruptions was lower than in the previous century, with the mean eruption rate falling to 0.18 m3s-1. This paper summarises: the characteristics of the eruptions that occurred between the period of 1600 to present; the particularities of the societal responses over time and the role of the authorities; and, the important lessons this history holds for the management of present-day civil defence planning in the region. People responded to the eruptions at three levels: as members of a family and extended family; as members of a community and, as citizens of the State. The State, however, was a minor player in responding to these eruptions until the early nineteenth century as the State then became more involved in each successive eruption as the responses moved to a more industrial nature rather than pre-industrial. Today emergencies are

  20. Constraints of mapped and unfolded slabs on Oligocene to present-day Western Mediterranean plate reconstructions: potential role of north Iberia continental delamination

    NASA Astrophysics Data System (ADS)

    Lee, Yi-Te; Wu, Jonny; Wu, Yi-Min; Suppe, John; Sibuet, Jean-Claude; Chevrot, Sebastien

    2015-04-01

    Seismic tomographic images of subducted lithospheric remnants under the western Mediterranean have provided new constraints for Oligocene to present-day plate reconstructions. In this study, we mapped slabs under the western Mediterranean and Iberia from regional seismic tomography (Chevrot et al., 2014; Bezada et al., 2013) and from MITP08 global tomography (Li et al., 2008). A newly developed method was used to unfold (ie. structurally restore) the mapped slabs to a model spherical Earth surface, minimizing area and shape distortion. Slab constraints were input into plate tectonic reconstructions using Gplates software. Our mapping confirms the existence of western Mediterranean slabs including the Betic-Alboran, Algerian, and Calabrian slabs that were previously identified by Spakman and Wortel (2004). When unfolded these mapped slabs fit together in an Oligocene plate reconstruction, within tomographic resolution limits. Slab stretching was not required. Slab segmentation supports the existence of a North Balearic transform. Here we emphasize the potential importance for western Mediterranean tectonics of antoher slab under Iberia that we call the 'mid-Iberia slab'. This slab was first identified by Sibuet et al. (2004) and interpreted to be a Neotethyan suture. We have mapped this slab in detail from recent regional tomography (Chevrot et al., 2014). Our mapped slab is sub-vertical and strikes E-W under the southern margins of the Duero and Ebro basins. We newly interpret this slab to be delaminated northern Iberian continental lithosphere. We propose that continental delamination occurred during the Oligocene and produced uplifted Iberian Meseta topography, internally-drained basins, and high mean elevations that still persist today. We show how Oligocene northern Iberian continental delamination could have initiated subduction and rollback of the western Mediterranean

  1. Paleontological records indicate the occurrence of open woodlands in a dry inland climate at the present-day Arctic coast in western Beringia during the Last Interglacial

    NASA Astrophysics Data System (ADS)

    Kienast, Frank; Wetterich, Sebastian; Kuzmina, Svetlana; Schirrmeister, Lutz; Andreev, Andrei A.; Tarasov, Pavel; Nazarova, Larisa; Kossler, Annette; Frolova, Larisa; Kunitsky, Viktor V.

    2011-08-01

    Permafrost records, accessible at outcrops along the coast of Oyogos Yar at the Dmitry Laptev Strait, NE-Siberia, provide unique insights into the environmental history of Western Beringia during the Last Interglacial. The remains of terrestrial and freshwater organisms, including plants, coleopterans, chironomids, cladocerans, ostracods and molluscs, have been preserved in the frozen deposits of a shallow paleo-lake and indicate a boreal climate at the present-day arctic mainland coast during the Last Interglacial. Terrestrial beetle and plant remains suggest the former existence of open forest-tundra with larch ( Larix dahurica), tree alder ( Alnus incana), birch and alder shrubs ( Duschekia fruticosa, Betula fruticosa, Betula divaricata, Betula nana), interspersed with patches of steppe and meadows. Consequently, the tree line was shifted to at least 270 km north of its current position. Aquatic organisms, such as chironomids, cladocerans, ostracods, molluscs and hydrophytes, indicate the formation of a shallow lake as the result of thermokarst processes. Steppe plants and beetles suggest low net precipitation. Littoral pioneer plants and chironomids indicate intense lake level fluctuations due to high evaporation. Many of the organisms are thermophilous, indicating a mean air temperature of the warmest month that was greater than 13 °C, which is above the minimum requirements for tree growth. These temperatures are in contrast to the modern values of less than 4 °C in the study area. The terrestrial and freshwater organism remains were found at a coastal exposure that was only 3.5 m above sea level and in a position where they should have been under sea during the Last Interglacial when the global sea level was 6-10 m higher than the current levels. The results suggest that during the last warm stage, the site was inland, and its modern coastal situation is the result of tectonic subsidence.

  2. Estimating present day extreme water level exceedance probabilities around the coastline of Australia: tides, extra-tropical storm surges and mean sea level

    NASA Astrophysics Data System (ADS)

    Haigh, Ivan D.; Wijeratne, E. M. S.; MacPherson, Leigh R.; Pattiaratchi, Charitha B.; Mason, Matthew S.; Crompton, Ryan P.; George, Steve

    2014-01-01

    The occurrence of extreme water levels along low-lying, highly populated and/or developed coastlines can lead to considerable loss of life and billions of dollars of damage to coastal infrastructure. Therefore it is vitally important that the exceedance probabilities of extreme water levels are accurately evaluated to inform risk-based flood management, engineering and future land-use planning. This ensures the risk of catastrophic structural failures due to under-design or expensive wastes due to over-design are minimised. This paper estimates for the first time present day extreme water level exceedence probabilities around the whole coastline of Australia. A high-resolution depth averaged hydrodynamic model has been configured for the Australian continental shelf region and has been forced with tidal levels from a global tidal model and meteorological fields from a global reanalysis to generate a 61-year hindcast of water levels. Output from this model has been successfully validated against measurements from 30 tide gauge sites. At each numeric coastal grid point, extreme value distributions have been fitted to the derived time series of annual maxima and the several largest water levels each year to estimate exceedence probabilities. This provides a reliable estimate of water level probabilities around southern Australia; a region mainly impacted by extra-tropical cyclones. However, as the meteorological forcing used only weakly includes the effects of tropical cyclones, extreme water level probabilities are underestimated around the western, northern and north-eastern Australian coastline. In a companion paper we build on the work presented here and more accurately include tropical cyclone-induced surges in the estimation of extreme water level. The multi-decadal hindcast generated here has been used primarily to estimate extreme water level exceedance probabilities but could be used more widely in the future for a variety of other research and practical

  3. Analysis of the global atmospheric methane budget using ECHAM-MOZ simulations for present-day, pre-industrial time and the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Basu, A.; Schultz, M. G.; Schröder, S.; Francois, L.; Zhang, X.; Lohmann, G.; Laepple, T.

    2014-01-01

    Atmospheric methane concentrations increased considerably from pre-industrial (PI) to present times largely due to anthropogenic emissions. However, firn and ice core records also document a notable rise of methane levels between the Last Glacial Maximum (LGM) and the pre-industrial era, the exact cause of which is not entirely clear. This study investigates these changes by analyzing the methane sources and sinks at each of these climatic periods. Wetlands are the largest natural source of methane and play a key role in determining methane budget changes in particular in the absence of anthropogenic sources. Here, a simple wetland parameterization suitable for coarse-scale climate simulations over long periods is introduced, which is derived from a high-resolution map of surface slopes together with various soil hydrology parameters from the CARAIB vegetation model. This parameterization was implemented in the chemistry general circulation model ECHAM5-MOZ and multi-year time slices were run for LGM, PI and present-day (PD) climate conditions. Global wetland emissions from our parameterization are 72 Tg yr-1 (LGM), 115 Tg yr-1 (PI), and 132 Tg yr-1 (PD). These estimates are lower than most previous studies, and we find a stronger increase of methane emissions between LGM and PI. Taking into account recent findings that suggest more stable OH concentrations than assumed in previous studies, the observed methane distributions are nevertheless well reproduced under the different climates. Hence, this is one of the first studies where a consistent model approach has been successfully applied for simulating methane concentrations over a wide range of climate conditions.

  4. Evaluation of Preindustrial to Present-day Black Carbon and its Albedo Forcing from Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

    SciTech Connect

    Lee, Y. H.; Lamarque, J.-F.; Flanner, M. G.; Jiao, C.; Shindell, Drew; Berntsen, T.; Bisiauxs, M.; Cao, J.; Collins, W. J.; Curran, M.; Edwards, R.; Faluvegi, G.; Ghan, Steven J.; Horowitz, L.; McConnell, J.R.; Ming, J.; Myhre, G.; Nagashima, T.; Naik, Vaishali; Rumbold, S.; Skeie, R. B.; Sudo, K.; Takemura, T.; Thevenon, F.; Xu, B.; Yoon, Jin-Ho

    2013-03-05

    As a part of the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP), we evaluate the historical black carbon (BC) aerosols simulated by 8 ACCMIP models against the observations including 12 ice core records, a long-term surface mass concentrations and recent Arctic BC snowpack measurements. We also estimate BC albedo forcing by performing additional simulations using the NCAR Community Land and Sea-Ice model 4 with prescribed meteorology from 1996-2000, which includes the SNICAR BC-snow model. We evaluated the vertical profile of BC snow concentrations from these offline simulations to using recent BC snowpack measurements. Despite using the same BC emissions, global BC burden differs by approximately a factor of 3 among models due to the differences in aerosol removal parameterizations and simulated meteorology among models; 34 Gg to 103 Gg in 1850 and 82 Gg to 315 Gg in 2000. However,models agree well on 2.5~3 times increase in the global BC burden from preindustrial to present-day, which matches with the 2.5 times increase in BC emissions. We find a large model diversity at both NH and SH high latitude regions for BC burden and at SH high latitude regions for deposition fluxes. The ACCMIP simulations match the observed BC mass concentrations well in Europe and North America except at Jungfrauch and Ispra. However, the models fail to capture the Arctic BC seasonality due tosevere underestimations during winter and spring. Compared to recent snowpack measurements, the simulated vertically resolved BC snow concentrations are, on average, within a factor of 2-3 of observations except for Greenland and Arctic Ocean. However, model and observation differ widely due to missing interannual variations in emissions and possibly due to the choice of the prescribed meteorology period (i.e., 1996-2000).

  5. Interactive effects of ocean acidification and warming on coral reef associated epilithic algal communities under past, present-day and future ocean conditions

    NASA Astrophysics Data System (ADS)

    Vogel, N.; Cantin, N. E.; Strahl, J.; Kaniewska, P.; Bay, L.; Wild, C.; Uthicke, S.

    2016-06-01

    Epilithic algal communities play critical ecological roles on coral reefs, but their response to individual and interactive effects of ocean warming (OW) and ocean acidification (OA) is still largely unknown. We investigated growth, photosynthesis and calcification of early epilithic algal community assemblages exposed for 6 months to four temperature profiles (-1.1, ±0.0, +0.9, +1.6 °C) that were crossed with four carbon dioxide partial pressure (pCO2) levels (360, 440, 650, 940 µatm), under flow-through conditions and natural light regimes. Additionally, we compared the cover of heavily calcified crustose coralline algae (CCA) and lightly calcified red algae of the genus Peyssonnelia among treatments. Increase in cover of epilithic communities showed optima under moderately elevated temperatures and present pCO2, while cover strongly decreased under high temperatures and high-pCO2 conditions, particularly due to decreasing cover of CCA. Similarly, community calcification rates were strongly decreased at high pCO2 under both measured temperatures. While final cover of CCA decreased under high temperature and pCO2 (additive negative effects), cover of Peyssonnelia spp. increased at high compared to annual average and moderately elevated temperatures. Thus, cover of Peyssonnelia spp. increased in treatment combinations with less CCA, which was supported by a significant negative correlation between organism groups. The different susceptibility to stressors most likely derived from a different calcification intensity and/or mineral. Notably, growth of the epilithic communities and final cover of CCA were strongly decreased under reduced-pCO2 conditions compared to the present. Thus, CCA may have acclimatized from past to present-day pCO2 conditions, and changes in carbonate chemistry, regardless in which direction, negatively affect them. However, if epilithic organisms cannot further acclimatize to OW and OA, the interacting effects of both factors may change

  6. Little Ice Age versus Present Day: Comparison of Temperature, Precipitation and Seasonality in Speleothem Records from the Han-sur-Lesse Cave, Belgium.

    NASA Astrophysics Data System (ADS)

    Vansteenberge, S.; Van Opdenbosch, J.; Van Rampelbergh, M.; Verheyden, S.; Keppens, E.; Cheng, H.; Edwards, R. L.; Claeys, P. F.

    2015-12-01

    The Proserpine stalagmite is a 2 m large, tabular-shaped speleothem located in the Han-sur-Lesse cave in Belgium. The speleothem formed over the last 1000 years and is still growing. High-accuracy U/Th datings have indicated exceptionally high growth-rates of up to 2 mm per year. This, together with a well expressed annual layering, makes the Proserpine stalagmite an ideal candidate for high-resolution paleoclimate reconstructions of the last millennium. Previous work, including over 10 years of cave monitoring, has already learned us how short-term, i.e. decadal to seasonal, climate variations are incorporated within speleothem calcite from the Han-sur-Lesse cave system. It has been shown that δ18O and δ13C stable isotopes and trace element proxies of recently formed calcite reflect seasonal variations in temperature and precipitation of the near-cave environment (Verheyden et al, 2008; Van Rampelbergh et al., 2014). Now, this knowledge was used to infer local climate parameters further back in time to the period of +/- 1620-1630 CE, corresponding to one of the cold peaks within the Little Ice Age. Speleothem calcite was sampled at sub-annual resolution, with approximately 11 samples per year, for stable isotope analysis. LA-ICP-MS and µXRF analyses resulted in time series of trace elements. Preliminary results indicate a well expressed seasonal signal in δ13C and trace element composition but a multi-annual to decadal trend in δ18O. This combined proxy study eventually enables comparison of the expression of seasonality and longer term climate variations between a Little Ice Age cold peak and Present Day. References: Verheyden, S. et al., 2008, Monitoring climatological, hydrological and geochemical parameters in the Père Noël cave (Belgium): implication for the interpretation of speleothem isotopic and geochemical time-series. International Journal of Speleology, 37(3), 221-234. Van Rampelbergh, M. et al., 2014, Seasonal variations recorded in cave

  7. Aerosol Direct, Indirect, Semidirect, and Surface Albedo Effects from Sector Contributions Based on the IPCC AR5 Emissions for Preindustrial and Present-day Conditions

    NASA Technical Reports Server (NTRS)

    Bauer, Susanne E.; Menon, Surabi

    2012-01-01

    The anthropogenic increase in aerosol concentrations since preindustrial times and its net cooling effect on the atmosphere is thought to mask some of the greenhouse gas-induced warming. Although the overall effect of aerosols on solar radiation and clouds is most certainly negative, some individual forcing agents and feedbacks have positive forcing effects. Recent studies have tried to identify some of those positive forcing agents and their individual emission sectors, with the hope that mitigation policies could be developed to target those emitters. Understanding the net effect of multisource emitting sectors and the involved cloud feedbacks is very challenging, and this paper will clarify forcing and feedback effects by separating direct, indirect, semidirect and surface albedo effects due to aerosols. To this end, we apply the Goddard Institute for Space Studies climate model including detailed aerosol microphysics to examine aerosol impacts on climate by isolating single emission sector contributions as given by the Coupled Model Intercomparison Project Phase 5 (CMIP5) emission data sets developed for Intergovernmental Panel on Climate Change (IPCC) AR5. For the modeled past 150 years, using the climate model and emissions from preindustrial times to present-day, the total global annual mean aerosol radiative forcing is -0.6 W/m(exp 2), with the largest contribution from the direct effect (-0.5 W/m(exp 2)). Aerosol-induced changes on cloud cover often depends on cloud type and geographical region. The indirect (includes only the cloud albedo effect with -0.17 W/m(exp 2)) and semidirect effects (-0.10 W/m(exp 2)) can be isolated on a regional scale, and they often have opposing forcing effects, leading to overall small forcing effects on a global scale. Although the surface albedo effects from aerosols are small (0.016 W/m(exp 2)), triggered feedbacks on top of the atmosphere (TOA) radiative forcing can be 10 times larger. Our results point out that each

  8. Aerosol direct, indirect, semidirect, and surface albedo effects from sector contributions based on the IPCC AR5 emissions for preindustrial and present-day conditions

    NASA Astrophysics Data System (ADS)

    Bauer, Susanne E.; Menon, Surabi

    2012-01-01

    The anthropogenic increase in aerosol concentrations since preindustrial times and its net cooling effect on the atmosphere is thought to mask some of the greenhouse gas-induced warming. Although the overall effect of aerosols on solar radiation and clouds is most certainly negative, some individual forcing agents and feedbacks have positive forcing effects. Recent studies have tried to identify some of those positive forcing agents and their individual emission sectors, with the hope that mitigation policies could be developed to target those emitters. Understanding the net effect of multisource emitting sectors and the involved cloud feedbacks is very challenging, and this paper will clarify forcing and feedback effects by separating direct, indirect, semidirect and surface albedo effects due to aerosols. To this end, we apply the Goddard Institute for Space Studies climate model including detailed aerosol microphysics to examine aerosol impacts on climate by isolating single emission sector contributions as given by the Coupled Model Intercomparison Project Phase 5 (CMIP5) emission data sets developed for Intergovernmental Panel on Climate Change (IPCC) AR5. For the modeled past 150 years, using the climate model and emissions from preindustrial times to present-day, the total global annual mean aerosol radiative forcing is -0.6 W/m2, with the largest contribution from the direct effect (-0.5 W/m2). Aerosol-induced changes on cloud cover often depends on cloud type and geographical region. The indirect (includes only the cloud albedo effect with -0.17 W/m2) and semidirect effects (-0.10 W/m2) can be isolated on a regional scale, and they often have opposing forcing effects, leading to overall small forcing effects on a global scale. Although the surface albedo effects from aerosols are small (0.016 W/m2), triggered feedbacks on top of the atmosphere (TOA) radiative forcing can be 10 times larger. Our results point out that each emission sector has varying

  9. Grainsize Patterns and Bed Evolution of the Rhone River (France): A Present-day Snapshot Following a Century and a Half of Human Modifications

    NASA Astrophysics Data System (ADS)

    Michal, T.; Parrot, E.; Piegay, H.

    2014-12-01

    Over the past 150 years the Rhône River has been heavily altered by human infrastructures. The first wave (1860 - 1930) of modifications consisted of dikes and groynes designed to narrow the channel and promote incision in order to facilitate navigation. A second period (1948 - 1986) involved the construction of a series of canals and dams for hydroelectricity production. These works bypass multiple reaches of the original channel and drastically reduce the discharge and sediment load reaching them. A comprehensive study underway is aimed at describing the present-day morphology of the Rhone along its 512 km length from its source at Lake Geneva to its sink at the Mediterranean Sea and quantifying the role of management works in the evolution to its current state. Grainsize distributions and armour ratios were determined using a combination of Wolman counts on bars and in shallow channels and dredge samples collected from a boat in navigable reaches. Long profiles were constructed from historical bathymetric maps and bathymetric data collected between 1950 - 2010. Differential long profiles highlighting changes in bed elevation due to sediment storage and erosion were analyzed for three different periods: post-channelization, post-dam construction, and a recent period of major floods. Results show a complex discontinuous pattern in grainsize associated with hydraulic discontinuities imposed by dams. The D50 for bypass reaches is 45 mm compared to a D50 of 34 mm in the non-bypass reaches. The lower D50 as well as a finer tailed distribution in non-bypass reaches reflects fining associated with storage upstream of dams. Armour ratios are on average around 2 but are notably higher for reaches in the middle section of the Rhone. The average incision rate was 1.8 cm/yr for the period of post-channelization and 1.2 cm/yr following dam construction, suggesting the post-dam Rhone was already partially armoured due to incision associated with channelization preceding dam

  10. Evaluation of preindustrial to present-day black carbon and its albedo forcing from Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

    NASA Technical Reports Server (NTRS)

    Lee, Y. H.; Lamarque, J.-F.; Flanner, M. G.; Jiao, C.; Shindell, D. T.; Bernsten, T.; Bisiaux, M. M.; Cao, J.; Collins, W. J.; Curran, M.; Edwards, R.; Faluvegi, G.; Ghan, S.; Horowitz, L. W.; McConnell, J. R.; Ming, J.; Myhre, G.; Nagashima, T.; Naik, V.; Rumbold, S. T.; Skeie, R. B.; Sudo, K.; Takemura, T.; Thevenon, F.; Xu, B.; Yoon, J.-H.

    2013-01-01

    As part of the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP), we evaluate the historical black carbon (BC) aerosols simulated by 8 ACCMIP models against observations including 12 ice core records, long-term surface mass concentrations, and recent Arctic BC snowpack measurements. We also estimate BC albedo forcing by performing additional simulations using offline models with prescribed meteorology from 1996-2000. We evaluate the vertical profile of BC snow concentrations from these offline simulations using the recent BC snowpack measurements. Despite using the same BC emissions, the global BC burden differs by approximately a factor of 3 among models due to differences in aerosol removal parameterizations and simulated meteorology: 34 Gg to 103 Gg in 1850 and 82 Gg to 315 Gg in 2000. However, the global BC burden from preindustrial to present-day increases by 2.5-3 times with little variation among models, roughly matching the 2.5-fold increase in total BC emissions during the same period.We find a large divergence among models at both Northern Hemisphere (NH) and Southern Hemisphere (SH) high latitude regions for BC burden and at SH high latitude regions for deposition fluxes. The ACCMIP simulations match the observed BC surface mass concentrations well in Europe and North America except at Ispra. However, the models fail to predict the Arctic BC seasonality due to severe underestimations during winter and spring. The simulated vertically resolved BC snow concentrations are, on average, within a factor of 2-3 of the BC snowpack measurements except for Greenland and the Arctic Ocean. For the ice core evaluation, models tend to adequately capture both the observed temporal trends and the magnitudes at Greenland sites. However, models fail to predict the decreasing trend of BC depositions/ice core concentrations from the 1950s to the 1970s in most Tibetan Plateau ice cores. The distinct temporal trend at the Tibetan Plateau ice cores

  11. Late Miocene to present-day exhumation and uplift of the Internal Zone of the Rif chain: Insights from low temperature thermochronometry and basin analysis

    NASA Astrophysics Data System (ADS)

    Romagny, A.; Ph. Münch; Cornée, J.-J.; Corsini, M.; Azdimousa, A.; Melinte-Dobrinescu, M. C.; Drinia, H.; Bonno, M.; Arnaud, N.; Monié, P.; Quillévéré, F.; Ben Moussa, A.

    2014-07-01

    Located on the margin of the west Alboran basin, the Gibraltar Arc (Betic-Rif mountain belt) displays post-Pliocene vertical movements evidenced by uplifted marine sedimentary basins and marine terraces. Quantification of vertical movements is an important clue to understand the origin of present-day relief generation in the Betic-Rif mountain chain together with the causes of the Messinian Salinity Crisis. In this paper, we present the results of a pluridisciplinary study combining an analysis of low temperature thermochronology and Pliocene basins evolution to constrain the exhumation history and surface uplift of internals units of the Rif belt (Northern Morocco). The mean (U-Th)/He apatite ages obtained from 11 samples are comprised between 14.1 and 17.8 Ma and display a wide dispersion, which could be explained by a great variability of apatite chemistries in the analyzed samples. No correlations between altitude and age have been found along altitudinal profile suggesting a rapid exhumation during this period. Thermal modeling using our (U-Th)/He apatite ages and geochronological data previously obtained in the same area (40Ar/39Ar and K/Ar data on biotite, zircon and apatite fission track) allow us to propose a cooling history. The rocks suffered a rapid cooling at 60-100 °C/Ma between 22.5 and 19 Ma, then cooled to temperatures around 40 °C between 19 and 18 Ma. They were re-heated at around 110 °C between 18 and 15 Ma then rapidly cooled and exhumed to reach the surface temperature at around 13 Ma. The re-heating could be related to a renewal in thrusting and burying of the inner zones. Between 15 and 13 Ma the cooling resumed at a rate of 50 °C/Ma indicating an exhumation rate of 0.8 mm/y considering an average 40 °C/km geothermal gradient. This exhumation may be linked to the extension in the Alboran Sea. Otherwise biostratigraphic and sedimentological analysis of Pliocene basins of the internal Rif provided informations on the more recent events

  12. Submarine gravitative mass movements in the ``Corinth Gulf'' graben in Greece. A natural laboratory for the enhancement of present day knowledge on mass movements.

    NASA Astrophysics Data System (ADS)

    Papatheodorou, G.; Stefatos, A.; Christodoulou, D.; Ferentinos, G.

    2003-04-01

    caused by the deformation of the underlying sediments. This can be attributed to the partial loss of sediment strength due to either the remoulding or excess pore fluid pressure caused by the cyclic loading induced by the earthquake. Historical observations give evidence that: (i) coastal mass movements like those described above have also occurred in the past, (ii) mass movements have been triggered by earthquakes or heavy rain and (iii) the frequency occurrence of mass movements all over the Corinth Gulf graben may be once in every two or three years. These mass movements have caused destruction to the coastal infrastructure and also to offshore submarine cables. The review of the state of the art on the existing knowledge suggests, that in the past three decades, there have been great scientific and engineering advances in the recognition of mass movements on the seafloor and of the basic geological processes involved. There is however, a lack of scientific knowledge related to the prediction of the reactivation of existing mass movements and to the identification of slopes prone to failure. This knowledge could be acquired by the continuous monitoring of the changes in the physical and mechanical properties of the sediments. The study of the continuous changes in the sediment properties is hindered mainly by the high cost of monitoring in the unfriendly ocean environment. Taking the aforementioned into consideration, and bearing in mind that the Gulf of Corinth is a semi-enclosed embayment characterized by calm sea conditions, the Gulf would therefore, be an ideal natural laboratory for the further advancement of present day knowledge on mass movement processes and slope stability prediction.

  13. Benthic foraminifera from the deep-water Niger delta (Gulf of Guinea): Assessing present-day and past activity of hydrate pockmarks

    NASA Astrophysics Data System (ADS)

    Fontanier, C.; Koho, K. A.; Goñi-Urriza, M. S.; Deflandre, B.; Galaup, S.; Ivanovsky, A.; Gayet, N.; Dennielou, B.; Grémare, A.; Bichon, S.; Gassie, C.; Anschutz, P.; Duran, R.; Reichart, G. J.

    2014-12-01

    13C values. Dead faunas carry a complex time-averaged message, integrating taphonomic gains and losses related to the temporal variability of gas emission. They reveal major faunal differences that may be useful to detect gas hydrate seepages in different pockmark stages.

  14. [Present day Marxist sociology and psychoanalysis].

    PubMed

    Biran, S

    1979-01-01

    The main common theme in psychoanalysis and Marxist sociology is the understanding that it is not consciousness that determines being, but being (spiritual, social) that determines consciousness. The different variations of Marxist movements today are in fact distant from Marx's theory of sociology. They have become representatives of utopian socialism, using anarchistic methods to achieve that aim. This development can only be understood as a social neurosis, with the narcistic frustation of the intellectual class as its cause, and grandiose claims, intolerance, dogmatic thinking and destructive behaviour as its symptoms. The only justified criticism of psychoanalysis from the pseudo-Marxist side is based on the imperfection and error in the analytical doctrine of superego. This should be replaced by the idea of conscious, subjective, emotional morality which clearly explains the aggression contained in social structures. PMID:498762

  15. Cosmology: from Pomeranchuk to the Present Day

    NASA Astrophysics Data System (ADS)

    Dolgov, A. D.

    A short and, due to lack of time (half a century of the science progress in half an hour), rather superficial review on the development of cosmology for scientists working on particle and nuclear physics is presented. The introductory historical part is mostly dedicated to the fundamental works done in Russia (USSR), but not always well known outside the country. Next, the key papers on theory and on astronomical observations, which determined the progress in cosmology during the last half-century or posed crucial problem, are discussed. Among them there are inflation, baryogenesis, dark matter, dark energy, the vacuum energy problem, modification of gravity at large scales, and angular fluctuations of the cosmic microwave background radiation. The presentation is probably biased towards cosmology as it is seen from Russia (or from ITEP) and reflects personal prejudice of the author.

  16. Cosmology: from Pomeranchuk to the present day

    NASA Astrophysics Data System (ADS)

    Dolgov, A. D.

    2014-02-01

    A review of half a century of cosmology is presented for an intended audience of elementary particle physicists. The review is based on a half-hour seminar talk (at the Institute of Theoretical and Experimental Physics, ITEP) and is therefore brief and superficial. The introductory historical section is mostly devoted to the fundamental work done in, but not always known outside, Russia (USSR). Foundational works and astronomical observations instrumental in shaping the field are discussed, as are inflation, baryosynthesis, dark matter and dark energy, vacuum energy, large-scale gravity modifications, and microwave background angular fluctuations. The presentation is admittedly not entirely objective but rather is given from the Russian (ITEP) perspective and is influenced by the author's personal views and biases.

  17. Global three-dimensional model calculations of the budgets and present-day atmospheric lifetimes of CF2ClCFCl2 (CFC-113) and CHClF2 (CFC-22)

    NASA Technical Reports Server (NTRS)

    Golombek, Amram; Prinn, Ronald G.

    1989-01-01

    The annual percentage increases in concentrations of the chlorofluorocarbons CFC-113 (an industrial solvent) and CFC-22 (a refrigerant) are the highest among major chlorofluorocarbons in the atmosphere today. The present-day atmospheric lifetimes for these species are computed using a global three-dimensional dynamical-chemical model. The present-day lifetimes of both are long (15.5 years for CFC-22 and 136 or 195 years for CFC-113, depending on assumed O2 absorption cross sections), underscoring the need to decrease their emissions in order to minimize their future role in ozone destruction and greenhouse warming.

  18. Revealing Rembrandt

    PubMed Central

    Parker, Andrew J.

    2014-01-01

    The power and significance of artwork in shaping human cognition is self-evident. The starting point for our empirical investigations is the view that the task of neuroscience is to integrate itself with other forms of knowledge, rather than to seek to supplant them. In our recent work, we examined a particular aspect of the appreciation of artwork using present-day functional magnetic resonance imaging (fMRI). Our results emphasized the continuity between viewing artwork and other human cognitive activities. We also showed that appreciation of a particular aspect of artwork, namely authenticity, depends upon the co-ordinated activity between the brain regions involved in multiple decision making and those responsible for processing visual information. The findings about brain function probably have no specific consequences for understanding how people respond to the art of Rembrandt in comparison with their response to other artworks. However, the use of images of Rembrandt's portraits, his most intimate and personal works, clearly had a significant impact upon our viewers, even though they have been spatially confined to the interior of an MRI scanner at the time of viewing. Neuroscientific studies of humans viewing artwork have the capacity to reveal the diversity of human cognitive responses that may be induced by external advice or context as people view artwork in a variety of frameworks and settings. PMID:24795552

  19. Using present-day patterns of interseismic coupling to model the C.E. 1707 Hōei earthquake and simulate tsunami inundation of Lake Ryuuoo in the Bungo Channel, southwestern Japan

    NASA Astrophysics Data System (ADS)

    Baranes, H. E.; Woodruff, J. D.; Loveless, J. P.; Cheng, W.; Weiss, R.; Kanamaru, K.

    2015-12-01

    The C.E. 1707 Hōei event is often considered the worst-case scenario for a Nankai Trough earthquake and tsunami impacting southwestern Japan, and recent estimates of the earthquake's magnitude have exceeded MW 9. However, when paired with tsunami simulations, previously published earthquake models for the event fail to match sedimentological and historical records of 1707 tsunami height in Shikoku and Kyushu. Specifically, models do not produce a sufficiently large tsunami in the northern Bungo Channel and Seto Inland Sea without also over-predicting tsunami heights along the open Pacific coastlines of Shikoku and Kyushu. Here, we apply a newly developed rupture model that uses present-day patterns of geodetically imaged interseismic coupling to inform patterns in coseismic slip. Along the southwestern extent of the plate interface (the Hyuga-nada area), there is a region of weak coupling up-dip along the trench axis and a region of strong coupling down-dip beneath Shikoku and Kyushu. Following this pattern, the new earthquake model produces less coseismic uplift offshore and greater subsidence in an inland region that includes the Bungo Channel. This combination of regional subsidence and a tsunami wave more focused to the Bungo Channel results in inundation patterns more consistent with historical and sedimentological observations in the Hyuga-nada area. We also run the tsunami simulation on a high-resolution grid around Lake Ryuuoo, a back-barrier lake in the northern Bungo Channel that contains a marine overwash deposit from the 1707 tsunami. We apply a simple sediment transport model to demonstrate that the coupling-based rupture scenario produces flow over Lake Ryuuoo's barrier capable of transporting the maximum grain size observed in the lake's 1707 deposit. These findings suggest that spatial trends in our present-day coupling model are more consistent with inundation patterns observed for large tsunamis generated by coseismic rupture along the Nankai

  20. Seafloor morphology of the Eurasia-Nubia (Africa) plate boundary between the Tore-Madeira Rise and the Straits of Gibraltar: a case of coexistent Mesozoic through Present day features of tectonic, oceanographic and sedimentary origin

    NASA Astrophysics Data System (ADS)

    Terrinha, Pedro; Duarte, João.; Valadares, Vasco; Batista, Luis; Zitellini, Nevio; Grácia, Eulalia; Lourenço, Nuno; Rosas, Filipe; Roque, Cristina

    2010-05-01

    The joint use of more than 10.000 km multichannel seismic reflection profiles and 180.000km2 of multibeam swath bathymetry and backscatter allowed for a new vision of the seafloor tectonic and geomorphic processes of the area that encompasses the present day plate boundary between Africa and Eurasia, between the Gibraltar Straits and the Tore-Madeira Rise, in the southern sector of the North Atlantic Ocean. The interpretation of this data allowed for the detailed description of the seafloor morphology (i.e. a morphologic map) and the classification of the morphologic features in what respects the genetic process and age. It can be seen that in the same region coexist morphologic features that result from tectonic processes associated with the Triassic-Cretaceous break-up of Pangea, the Paleogene-Miocene compressive phase, the Miocene through Present subduction under the Gibraltar Arc (Gutscher et al., 2002), the Pliocene-Quaternary wrench tectonics and possible coeval plate boundary (Zitellini et al., 2009), the Present day mud volcanism and propagation of the compressive deformation along the West Continental Margin of Portugal (Terrinha et al., 2009). Interpretation of the seismic profiles together with the bathymetry allows the understanding of endogenous and exogenous processes that creates reliefs associated with active structures (related to the Miocene through Present compressive stress field). Other reliefs generated in Mesozoic times by analogous processes can be as well preserved as these active ones. In what concerns exogenous processes, the analysis of the two datasets (reflection seismics and bathymetry) allowed for the description of morphologic features associated with oceanic currents that interact with the seafloor forming these important features. As is the case of the well known active contourites but also less known features, like giant scours at 4 km water depth that have recently been described, suggesting the interaction of deep currents and

  1. Sedimentological imprints of environmental variability at the Balkan Peninsula on the sediment sequence of Lake Ohrid (Macedonia, Albania) between the Mid Pleistocene Transition and present days: The ICDP SCOPSCO project

    NASA Astrophysics Data System (ADS)

    Francke, Alexander; Wagner, Bernd; Leicher, Niklas; Raphael, Gromig; Leng, Melanie; Lacey, Jack; Vogel, Hendrik; Baumgarten, Henrike; Thomas, Wonik; Zanchetta, Giovanni; Roberto, Sulpizio; Krastel, Sebastian; Lindhorst, Katja

    2015-04-01

    The UNESCO World Heritage site of Lake Ohrid in the Balkans is thought to be the oldest, continuously existing lake in Europe. In order to unravel the geological and evolutionary history of the lake, a deep drilling campaign was conducted in spring 2013 under the umbrella of the ICDP SCOPSCO project. At the coring site "DEEP" in central parts of the lake, more than 1,500 m of sediments were recovered down to a penetration depth of 569 m blf. This sediment sequence is assumed to be more than 1.2 Ma old and likely covers the entire lacustrine deposits of the Lake Ohrid Basin. Currently, an age model for the upper 260m of the DEEP- site sequence is available. This age model is based on chronological tie points (tephrochronology), and wiggle matching of down hole logging data and (bio-)geochemistry data (XRF, TIC, TOC) from the core sequence to the global benthic stack LR04 and local insolation patterns. The data suggests that the upper 260 m of the DEEP-site sequence corresponds to the time period between the Mid Pleistocene Transition (MPT) and present days. During this period, the sedimentological properties of the sediments show a strong dependency on environmental variability in the area. Interglacial deposits appear massive or marbled, contain up to 80 % of CaCO3 (high TIC), high amounts of organic matter (high TOC) and biogenic silica (high BSi), and low contents of clastic material. Glacial deposits are predominantly marbled and calcite is generally absent. Similarly, the amounts of organic matter and biogenic silica are low, and glacial sediments predominately consist of clastic matter. Distinct layers of siderite and uniformly distributed Fe- or Mn- oxides occur in the glacial deposits, vivianite concretions occur in both the glacial and interglacial periods. High CaCO3 contents in deposits formed during warm (interglacial) periods are also known from studies on short pilot cores from Lake Ohrid and are triggered by increased productivity in the lake, such as

  2. Assessing the volcanic hazard for Rome: 40Ar/39Ar and In-SAR constraints on the most recent eruptive activity and present-day uplift at Colli Albani Volcanic District

    NASA Astrophysics Data System (ADS)

    Marra, F.; Gaeta, M.; Giaccio, B.; Jicha, B. R.; Palladino, D. M.; Polcari, M.; Sottili, G.; Taddeucci, J.; Florindo, F.; Stramondo, S.

    2016-07-01

    We present new 40Ar/39Ar data which allow us to refine the recurrence time for the most recent eruptive activity occurred at Colli Albani Volcanic District (CAVD) and constrain its geographic area. Time elapsed since the last eruption (36 kyr) overruns the recurrence time (31 kyr) in the last 100 kyr. New interferometric synthetic aperture radar data, covering the years 1993-2010, reveal ongoing inflation with maximum uplift rates (>2 mm/yr) in the area hosting the most recent (<200 ka) vents, suggesting that the observed uplift might be caused by magma injection within the youngest plumbing system. Finally, we frame the present deformation within the structural pattern of the area of Rome, characterized by 50 m of regional uplift since 200 ka and by geologic evidence for a recent (<2000 years) switch of the local stress-field, highlighting that the precursors of a new phase of volcanic activity are likely occurring at the CAVD.

  3. Genetic structure and forensic parameters of 38 Indels for human identification purposes in eight Mexican populations.

    PubMed

    Martínez-Cortés, G; Gusmão, L; Pereira, R; Salcido, V H; Favela-Mendoza, A F; Muñoz-Valle, J F; Inclán-Sánchez, A; López-Hernández, L B; Rangel-Villalobos, H

    2015-07-01

    Insertion-deletions for human identification purposes (HID-Indels) offer advantages to solve particular forensic situations and complex paternity cases. In Mexico, admixed population known as Mestizos is the largest (∼90%), plus a number of Amerindian groups (∼10%), which have not been studied with HID-Indels. For this reason, allele frequencies and forensic parameters for 38 HID-Indels were estimated in 531 unrelated individuals from one Amerindian (Purépecha) and seven Mestizo populations from different regions of the country. Genotype distribution was in agreement with Hardy-Weinberg expectations in almost all loci/populations. The linkage disequilibrium (LD) test did not reveal possible associations between loci pairs in all eight Mexican populations. The combined power of discrimination was high in all populations (PD >99.99999999998%). However, the power of exclusion of the 38 HID-Indel system (PE >99.6863%) was reduced regarding most of autosomal STR kits. The assessment of genetic structure (AMOVA) and relationships between populations (FST) demonstrated significant differences among Mexican populations, mainly of the Purépecha Amerindian group. Among Mexican-Mestizos, three population clusters consistent with geography were defined: (i) North-West region: Chihuahua, Sinaloa, and Jalisco; (ii) Central-Southern region: Mexico City, Veracruz and Yucatan; (iii) South region: Chiapas. In brief, this report validates the inclusion of the 38 HID-Indel system in forensic casework and paternity cases in seven Mexican-Mestizo populations from different regions, and in one Mexican Amerindian group. PMID:25988907

  4. QCD relics in the present-day Universe?

    SciTech Connect

    Ribeiro, J. E. F. T.; Antonov, D.; Nefediev, A. V.

    2011-05-23

    A possibility is suggested for the formation in the Universe of domains occupied by coherent-like states of strongly correlated quark-antiquark pairs. Only domains of the radius larger than 5 fm had a chance to survive over the entire history of the Universe, while the requirement of stability against the gravitational collapse restricts the maximum domain's radius to 14 km. Within the Generalised Nambu-Jona-Lasinio model, an exponential suppression with the domain's volume is found for the overlap between the macroscopic ground-state wavefunction of the quark-antiquark pairs and the QCD vacuum. This finding supports, at the microscopic level, the above arguments in favour of the stability of the domains.

  5. Active Immunization—Some Present-Day Problems

    PubMed Central

    1941-01-01

    Diphtheria.—Immunization is safe and effective. Compulsory measures are indicated, especially for the younger age-groups. The Schick test may be reserved for selected groups and to control modified methods. Proper spacing of doses of prophylactics and periodic reinoculation will ensure a high level of immunity. It is important to beware of “one-shot” methods. Indiscriminate swabbing is to be discouraged; high carrier rates are an indication for widespread diphtheria prophylaxis. Enteric fever.—Mass immunization is desirable in many areas, although there is no justification for compulsion except for people exposed to special risks. In deciding upon dosage of vaccine, more attention should be paid to physical state and body-weight. After the primary course, very small periodic doses (for example o.i.c.c) are worthy of trial. Vaccine can be given during an epidemic without increasing the chances of infection. Tetanus.—Two doses of toxoid spaced by six weeks give useful immunity. Women give significantly higher titres than men. A third dose of i.o.c.c. after a long interval—seven to nine months—often produces a dramatic rise in circulating antitoxin, and counteracts any tendency to waning immunity. Smallpox.—As vaccination has not been made compulsory in this country, infection by virulent strains from the continent may tax the resources of the public health services. Whooping-cough.—The large number of injections of vaccine usually recommended is a deterrent to mass immunization. Research into the possibility of fewer doses and wider spacing is indicated. Other diseases are considered briefly. Combined immunization.—It may be useful to combine diphtheria T.A.F. and tetanus toxoid, also tetanus toxoid and T.A.B. vaccine. T.A.F. plus T.A.B. is probably contra-indicated for adults on account of severe reactions. Diphtheria A.P.T. should not be mixed with tetanus toxoid as it may go into solution and become ineffective. Sterilization of syringes and needles.—An intensive inoculation campaign is no excuse for slip-shod methods. PMID:19992328

  6. Present-day anthelmintics and perspectives on future new targets.

    PubMed

    Taman, Amira; Azab, Manar

    2014-07-01

    In absence of vaccines for the majority of helminths, chemotherapy is still the mainstay for controlling human helminthiases. However, a limited number of drugs are available in the market to combat parasitic helminths in human. Besides, the development and spread of drug resistance have declined the use of most currently available anthelmintics. Clearly, availability of new anthelmintic agents will be essential in the next few years. More research into the mechanisms of drug actions and their targets are eminent for the discovery and development of novel anthelmintic agents. Recent drug discovery techniques mostly rely on mechanism-based screening of compounds on heterologously expressed targets in bacterial, mammalian or yeast cells. Although this is usually a successful approach, it is money- and time-consuming; meanwhile, pharmaceutical companies prefer the tested target that is chosen based on basic research. The nervous system is the site of action of several chemotherapeutics including pesticides and antinematode drugs; accordingly, the nervous system continues to be a promising target. Recent advances in exploring helminths' nervous system, neurotransmitters and receptors have paved the way for the development of potential agents targeting the nervous system and its components. PMID:24894082

  7. Present-day uplift of the western Alps

    PubMed Central

    Nocquet, J.-M.; Sue, C.; Walpersdorf, A.; Tran, T.; Lenôtre, N.; Vernant, P.; Cushing, M.; Jouanne, F.; Masson, F.; Baize, S.; Chéry, J.; van der Beek, P. A.

    2016-01-01

    Collisional mountain belts grow as a consequence of continental plate convergence and eventually disappear under the combined effects of gravitational collapse and erosion. Using a decade of GPS data, we show that the western Alps are currently characterized by zero horizontal velocity boundary conditions, offering the opportunity to investigate orogen evolution at the time of cessation of plate convergence. We find no significant horizontal motion within the belt, but GPS and levelling measurements independently show a regional pattern of uplift reaching ~2.5 mm/yr in the northwestern Alps. Unless a low viscosity crustal root under the northwestern Alps locally enhances the vertical response to surface unloading, the summed effects of isostatic responses to erosion and glaciation explain at most 60% of the observed uplift rates. Rock-uplift rates corrected from transient glacial isostatic adjustment contributions likely exceed erosion rates in the northwestern Alps. In the absence of active convergence, the observed surface uplift must result from deep-seated processes. PMID:27346228

  8. Present-day aeolian activity in Herschel Crater, Mars

    NASA Astrophysics Data System (ADS)

    Cardinale, Marco; Silvestro, Simone; Vaz, David A.; Michaels, Timothy; Bourke, Mary C.; Komatsu, Goro; Marinangeli, Lucia

    2016-02-01

    In this report, we show evidence for ripple and dune migration in Herschel Crater on Mars. We estimate an average dune migration of 0.8 m and a minimum ripple migration of 1.1 m in a time span of 3.7 Earth-years. These dunes and ripples are mainly shaped by prevailing winds coming from the north, however we also report the presence of secondary winds which elongate the barchans' horns. Such a complex wind scenario is likely caused by the influence of winds blowing off the western crater rim as suggested by the Mars Regional Atmospheric Modeling System (MRAMS), an atmospheric mesoscale model. A multi-directional wind regime at the local scale is also supported by the observed bimodal distribution of the ripple trends. For the first time, a survey integrating the assessment of dune and ripple migration is presented, showing how dune topography can influence the migration patterns of ripples and how underlying topography appears to control the rates of dune migration.

  9. [Present-day metal-cutting tools and working conditions].

    PubMed

    Kondratiuk, V P

    1990-01-01

    Polyfunctional machine-tools of a processing centre type are characterized by a set of hygienic advantages as compared to universal machine-tools. But low degree of mechanization and automation of some auxiliary processes, and constructional defects which decrease the ergonomic characteristics of the tools, involve labour intensity in multi-machine processing. The article specifies techniques of allowable noise level assessment, and proposes hygienic recommendations, some of which have been introduced into practice. PMID:2328919

  10. Likelihood of nitrogen condensation in Titan's present-day atmosphere

    NASA Astrophysics Data System (ADS)

    Tokano, Tetsuya

    2016-04-01

    The temperature in Titan's upper troposphere measured by the Huygens Probe is relatively close to the nitrogen condensation point. This poses the question as to whether seasonal nitrogen condensation might occur on Titan analogously to seasonal carbon dioxide condensation on Mars. The likelihood of nitrogen condensation in Titan's atmosphere is investigated using tropospheric temperature data obtained by Cassini radio occultations and simulation with a general circulation model (GCM). The observed tropospheric temperature generally decreases towards both poles but does not reach the nitrogen condensation point anywhere. However, Cassini may not have sounded the coldest season and area in Titan's troposphere. The GCM simulation shows that in the upper troposphere the variable solar distance associated with Saturn's orbital eccentricity has a larger impact on the seasonal polar temperature variation than the variable solar declination associated with Saturn's obliquity. In the upper troposphere relevant for nitrogen condensation the annual minimum polar temperature is predicted to occur around the northern autumnal equinox, approximately one season after aphelion. This temperature is then 1-2 K lower than in the season of the Cassini/Huygens mission. It is possible if not certain that some nitrogen condensation with cloud formation occurs in the northern and southern polar region in the upper troposphere around the northern autumnal equinox. Under the present orbital parameters of Saturn and Titan nitrogen condensation may occur more frequently near the south pole than near the north pole.

  11. [Fire worship on Soratte: form prehistory to present days].

    PubMed

    Falchetti, Mario; Ottini, Laura

    2013-01-01

    Fire has always been involved in human thoughts, believes and actions. For many psychological reasons fire has been considered as living power: red as the human blood, warm as the human body, clearly shines in the night. Fire worship is very common, especially in regions where terrestrial fire is believed to be the image of the heavenly fire. Fire worship has represented the base for symbolic systems involved in the cultural-anthropological evolution of populations settled close to mount Soratte. Fire cults in this region have originated in independent and long-time separated contexts, according to available knowledge. Hirpi Sorani, ancient inhabitants of mount Soratte territory, celebrated Sorano Apollo by a famous fire walking ceremony, with a likely cathartic and apotropaic meaning, as reported by ancient Roman writers. The victory of Christianity over paganism caused the decline of these religious practices. The beginning of the XIX century witnessed the establishment ofa new kind of devotion to the Virgin Mary at the mount Soratte. Today, this religious piety-linked identity has weakened due to changes in lifestyles,from an agricultural to one based on outside home employment, and has been largely shifted on cultural and anthropological bases. In conclusion, fire worship at mount Soratte has evolved because of external influences and local inhabitants have reacted by asserting their own identity. PMID:25807785

  12. Present-day uplift of the western Alps

    NASA Astrophysics Data System (ADS)

    Nocquet, J.-M.; Sue, C.; Walpersdorf, A.; Tran, T.; Lenôtre, N.; Vernant, P.; Cushing, M.; Jouanne, F.; Masson, F.; Baize, S.; Chéry, J.; van der Beek, P. A.

    2016-06-01

    Collisional mountain belts grow as a consequence of continental plate convergence and eventually disappear under the combined effects of gravitational collapse and erosion. Using a decade of GPS data, we show that the western Alps are currently characterized by zero horizontal velocity boundary conditions, offering the opportunity to investigate orogen evolution at the time of cessation of plate convergence. We find no significant horizontal motion within the belt, but GPS and levelling measurements independently show a regional pattern of uplift reaching ~2.5 mm/yr in the northwestern Alps. Unless a low viscosity crustal root under the northwestern Alps locally enhances the vertical response to surface unloading, the summed effects of isostatic responses to erosion and glaciation explain at most 60% of the observed uplift rates. Rock-uplift rates corrected from transient glacial isostatic adjustment contributions likely exceed erosion rates in the northwestern Alps. In the absence of active convergence, the observed surface uplift must result from deep-seated processes.

  13. [Fungus patents: from Pasteur to the present day].

    PubMed

    Bernardo-Álvarez, María Ángela

    2012-01-01

    At the end of the 19(th) century, the American Patent Office granted the patent known as "Pasteur's application", claiming the protection of a yeast strain. Since that date, the debate around biotechnology patents, especially for those that affect living organisms or part of them, has grown exponentially. In the present article, the Patent Law is reviewed, pointing out the particular problems about fungi or parts of them. Also, some of the fungus patents are discussed from the perspective of the ethical, economical, social and environmental aspects of these kind of patents. PMID:22677466

  14. Teaching with Social Media: Disrupting Present Day Public Education

    ERIC Educational Resources Information Center

    Meabon Bartow, Susan

    2014-01-01

    Because social technologies present illuminating educational, ethical, economic, and structural challenges to existing constructions of public education, they catalyze a fundamental examination of what public education should look like and be like in a democracy. Given their performances in other arenas, mobile and electronic technologies have the…

  15. The ethical debate on present day paternity testing practices.

    PubMed

    Mertens, G

    2006-01-01

    The last years, the number of paternity tests on buccal swabs sold over the internet as "test kits", has steeply increased. The commercial providers of these services facilitate controversial practices, including clandestine sampling at home, anonymous sending off for analysis, motherless testing and using "stolen" personal objects containing biological material (combs, cigarette butts). This has led to concern on the consequences on the family unit--especially the child--which may suffer emotionally, physically and financially. In reaction, legal initiatives are appearing throughout Europe. The UK Human Genetics Commission has advised that the non-consensual obtaining and analysis of personal genetic information should be a new criminal offence. The German Federal Court of Justice has ruled that paternity tests performed without the mother's knowledge are inadmissible as evidence in lawsuits. French law strictly forbids the application of DNA testing without the involvement of the court system. In Belgium, a proposal for law has been laid down where the offering to PMID:16792338

  16. Illiteracy, Sex and Occupational Status in Present-Day China.

    ERIC Educational Resources Information Center

    Lamontagne, Jacques

    This study determined the magnitude of disparity between men and women in China in relation to illiteracy and occupational status. Region and ethnicity are used as control variables. The data collected are from a 10 percent sampling of the 1982 census; the total sample size includes a population of 100,380,000 nationwide. The census questionnaire…

  17. Catalogues of variable stars from Parenago to the present day

    NASA Astrophysics Data System (ADS)

    Samus, N. N.

    2006-04-01

    After World War II, the International Astronomical Union made Soviet astronomers responsible for variable-star catalogues. This work has been continued ever since the first edition of the General Catalogue of Variable Stars compiled by the team headed by P.P. Parenago and B.V. Kukarkin and published in 1948. Currently, the catalogue work is a joint project of the Institute of Astronomy (Russian Academy of Sciences) and the Sternberg Astronomical Institute (Moscow University). This paper is a brief review of recent trends in the field of variable-star catalogues. Problems as well as new prospects related to modern large-scale automatic photometric sky surveys are discussed.

  18. Microplate model for the present-day deformation of Tibet

    USGS Publications Warehouse

    Thatcher, W.

    2007-01-01

    Site velocities from 349 Global Positioning System (GPS) stations are used to construct an 11-element quasi-rigid block model of the Tibetan Plateau and its surroundings. Rigid rotations of five major blocks are well determined, and average translation velocities of six smaller blocks can be constrained. Where data are well distributed the velocity field can be explained well by rigid block motion and fault slip across block boundaries. Residual misfits average 1.6 mm/yr compared to typical one standard deviation velocity uncertainties of 1.3 mm/yr. Any residual internal straining of the blocks is small and heterogeneous. However, residual substructure might well represent currently unresolved motions of smaller blocks. Although any smaller blocks must move at nearly the same rate as the larger blocks within which they lie, undetected relative motions between them could be significant, particularly where there are gaps in GPS coverage. Predicted relative motions between major blocks agree with the observed sense of slip and along-strike partitioning of motion across major faults. However, predicted slip rates across Tibet's major strike-slip faults are low, only 5-12 mm/yr, a factor of 2-3 smaller than most rates estimated from fault offset features dated by radiometric methods as ???2000 to ???100,000 year old. Previous work has suggested that both GPS data and low fault slip rates are incompatible with rigid block motions of Tibet. The results reported here overcome these objections.

  19. Present-day uplift of the western Alps.

    PubMed

    Nocquet, J-M; Sue, C; Walpersdorf, A; Tran, T; Lenôtre, N; Vernant, P; Cushing, M; Jouanne, F; Masson, F; Baize, S; Chéry, J; van der Beek, P A

    2016-01-01

    Collisional mountain belts grow as a consequence of continental plate convergence and eventually disappear under the combined effects of gravitational collapse and erosion. Using a decade of GPS data, we show that the western Alps are currently characterized by zero horizontal velocity boundary conditions, offering the opportunity to investigate orogen evolution at the time of cessation of plate convergence. We find no significant horizontal motion within the belt, but GPS and levelling measurements independently show a regional pattern of uplift reaching ~2.5 mm/yr in the northwestern Alps. Unless a low viscosity crustal root under the northwestern Alps locally enhances the vertical response to surface unloading, the summed effects of isostatic responses to erosion and glaciation explain at most 60% of the observed uplift rates. Rock-uplift rates corrected from transient glacial isostatic adjustment contributions likely exceed erosion rates in the northwestern Alps. In the absence of active convergence, the observed surface uplift must result from deep-seated processes. PMID:27346228

  20. A comparative study of prebiotic and present day translational models

    NASA Technical Reports Server (NTRS)

    Rein, R.; Raghunathan, G.; Mcdonald, J.; Shibata, M.; Srinivasan, S.

    1986-01-01

    It is generally recognized that the understanding of the molecular basis of primitive translation is a fundamental step in developing a theory of the origin of life. However, even in modern molecular biology, the mechanism for the decoding of messenger RNA triplet codons into an amino acid sequence of a protein on the ribosome is understood incompletely. Most of the proposed models for prebiotic translation lack, not only experimental support, but also a careful theoretical scrutiny of their compatibility with well understood stereochemical and energetic principles of nucleic acid structure, molecular recognition principles, and the chemistry of peptide bond formation. Present studies are concerned with comparative structural modelling and mechanistic simulation of the decoding apparatus ranging from those proposed for prebiotic conditions to the ones involved in modern biology. Any primitive decoding machinery based on nucleic acids and proteins, and most likely the modern day system, has to satisfy certain geometrical constraints. The charged amino acyl and the peptidyl termini of successive adaptors have to be adjacent in space in order to satisfy the stereochemical requirements for amide bond formation. Simultaneously, the same adaptors have to recognize successive codons on the messenger. This translational complex has to be realized by components that obey nucleic acid conformational principles, stabilities, and specificities. This generalized condition greatly restricts the number of acceptable adaptor structures.

  1. Satellite galaxies around present-day massive ellipticals

    NASA Astrophysics Data System (ADS)

    Ruiz, Pablo; Trujillo, Ignacio; Mármol-Queraltó, Esther

    2014-07-01

    Using the spectroscopic New York University Value-Added Galaxy Catalogue and the photometric photo-z catalogues of the Sloan Digital Sky Survey Data Release 7, we have explored the satellite distribution around ˜1000 massive (M⋆ ≳ 2 × 1011 M⊙) visually classified elliptical galaxies down to a satellite mass ratio of 1:400 (i.e. 5 × 108 ≲ Msat ≲ 2 × 1011 M⊙). Our host galaxies were selected to be representative of a mass complete sample. The satellites of these galaxies were searched within a projected radial distance of 100 kpc to their hosts. We have found that only 20-23 per cent of the massive ellipticals have at least a satellite down to a mass ratio 1:10. This number increases to 45-52 per cent if we explore satellites down to 1:100 and is >60-70 per cent if we go further down to 1:400. The average projected radial distance of the satellites to their hosts for our whole sample down to 1:400 is ˜59 kpc (which can be decreased at least down to 50 kpc if we account for incompleteness effects). The number of satellites per galaxy host only increases very mildly at decreasing the satellite mass. The fraction of mass which is contained in the satellites down to a mass ratio of 1:400 is 8 per cent of the total mass contained by the hosts. Satellites with a mass ratio from 1:2 to 1:5 (with ˜28 per cent of the total mass of the satellites) are the main contributor to the total satellite mass. If the satellites eventually infall into the host galaxies, the merger channel will be largely dominated by satellites with a mass ratio down to 1:10 (as these objects have 68 per cent of the total mass in satellites).

  2. Human Capital and Its Development in Present-Day Russia

    ERIC Educational Resources Information Center

    Nureev, R. M.

    2010-01-01

    In the broad sense of the word human capital is a specific form of capital that is embodied in people themselves. It consists of the individual's reserve of health, knowledge, skills, abilities, and motivations that enable him to increase his labor productivity and give him an income in the form of wages, salaries, and other income. The structure…

  3. Tracing galaxy evolution by their present-day luminosity function

    NASA Astrophysics Data System (ADS)

    Tempel, Elmo

    2011-04-01

    Galaxies, which are complex objects containing up to several tens of billions stars, as well as gas and dust, are remarkable objects. The Universe contains a very diverse "zoo" of galaxies: there are galaxies with a discy shape and spiral structure, elliptical galaxies, and even galaxies, which show no sign of structure. This variety of galaxies leads to the basic question: how the galaxies form and evolve and which processes shape the structure of galaxies? Due to the complexity of galaxy formation and evolution, this question is still an unresolved puzzle and it is one of the biggest challenges in modern cosmology. The present thesis is based on large galaxy surveys and concentrates on the large-scale structure: how galaxy evolution is related to the surrounding large-scale environment of superclusters and voids. To study the evolution of galaxies, we use the luminosity function, which is in this respect one of the most fundamental of all cosmological observables. One of the principal results of the present study was the conclusion that the evolution of spiral galaxies is almost independent of the global environment, especially for blue and red spirals separately, showing that the formation of spiral galaxies has to be similar in all environments. Meanwhile, the luminosity function of elliptical galaxies depends strongly on the environment. This shows that the global environmental density is an important factor (via merging history) in the formation of elliptical galaxies. The results of the present study show clearly, that besides the local/group environment, the global (supercluster-void) environment plays also an important role in the formation and evolution of galaxies. Accounting for the role of global environment can help to solve several problems in the present picture of galaxy formation and evolution.

  4. Present-day plate motions. [ocean bottom movements

    NASA Technical Reports Server (NTRS)

    Minster, J. B.; Jordan, T. H.

    1978-01-01

    An instantaneous plate-motion model, Relative Motion 2 (RM2), is obtained by inverting a data set comprising 110 spreading rates, 78 transform fault azimuths, and 142 earthquake slip vectors. RM2 is compared with angular velocity vectors which best fit the data along individual plate boundaries and, while the model performs close to optimally in most regions, attention is directed to those regions which are not suitably described by the model. Reasons for the discrepancies between RM2 and observations for the India-Antarctica plate boundary, the Pacific-India plate boundary, and the east-west trending transform fault azimuths observed in the French-American Mid-Ocean Undersea Study area are discussed.

  5. Syphilis: An Old Disease With Present-Day Implications.

    PubMed

    McNeil, Candice J; Bachmann, Laura H

    2016-01-01

    Syphilis continues to be a burden on the public health system. While men who have sex with men and HIV-infected individuals are the most affected populations, syphilis rates have also increased in reproductive-aged women, resulting in concurrent increases in congenital syphilis. Prompt diagnosis and treatment are requisite components of syphilis control. PMID:27621352

  6. Mammalian phylogeny reveals recent diversification rate shifts.

    PubMed

    Stadler, Tanja

    2011-04-12

    Phylogenetic trees of present-day species allow investigation of the rate of evolution that led to the present-day diversity. A recent analysis of the mammalian phylogeny challenged the view of explosive mammalian evolution after the Cretaceous-Tertiary (K/T) boundary (65 Mya). However, due to lack of appropriate methods, the diversification (speciation minus extinction) rates in the more recent past of mammalian evolution could not be determined. In this paper, I provide a method that reveals that the tempo of mammalian evolution did not change until ∼ 33 Mya. This constant period was followed by a peak of diversification rates between 33 and 30 Mya. Thereafter, diversification rates remained high and constant until 8.55 Mya. Diversification rates declined significantly at 8.55 and 3.35 Mya. Investigation of mammalian subgroups (marsupials, placentals, and the six largest placental subgroups) reveals that the diversification rate peak at 33-30 Mya is mainly driven by rodents, cetartiodactyla, and marsupials. The recent diversification rate decrease is significant for all analyzed subgroups but eulipotyphla, cetartiodactyla, and primates. My likelihood approach is not limited to mammalian evolution. It provides a robust framework to infer diversification rate changes and mass extinction events in phylogenies, reconstructed from, e.g., present-day species or virus data. In particular, the method is very robust toward noise and uncertainty in the phylogeny and can account for incomplete taxon sampling. PMID:21444816

  7. Revealing Mercury

    NASA Astrophysics Data System (ADS)

    Prockter, L. M.; Solomon, S. C.; Head, J. W.; Watters, T. R.; Murchie, S. L.; Robinson, M. S.; Chapman, C. R.; McNutt, R. L.

    2009-04-01

    The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, developed under NASA's Discovery Program, launched in August 2004. En route to insertion into orbit about Mercury in 2011, MESSENGER flies by Mercury three times. The first and second of these encounters were accomplished in January and October of 2008. These flybys viewed portions of Mercury's surface that were not observed by Mariner 10 during its reconnaissance of somewhat less than half of the planet in 1974-1975. All MESSENGER instruments operated during each flyby and returned a wealth of new data. Many of the new observations were focused on the planet's geology, including monochrome imaging at resolutions as high as 100 m/pixel, multispectral imaging in 11 filters at resolutions as high as 500 m/pixel, laser altimetry tracks extending over several thousands of kilometers, and high-resolution spectral measurements of several types of terrain. Here we present an overview of the first inferences on the global geology of Mercury from the MESSENGER observations. Whereas evidence for volcanism was equivocal from Mariner 10 data, the new MESSENGER images and altimetry provide compelling evidence that volcanism was widespread and protracted on Mercury. Color imaging reveals three common spectral units on the surface: a higher-reflectance, relatively red material occurring as a distinct class of smooth plains, typically with distinct embayment relationships interpreted to indicate volcanic emplacement; a lower-reflectance, relatively blue material typically excavated by impact craters and therefore inferred to be more common at depth; and a spectrally intermediate terrain that constitutes much of the uppermost crust. Three more minor spectral units are also seen: fresh crater ejecta, reddish material associated with rimless depressions interpreted to be volcanic centers, and high-reflectance deposits seen in some crater floors. Preliminary measurements of crater size

  8. How Are Preferences Revealed?

    PubMed Central

    Beshears, John; Choi, James J.; Laibson, David; Madrian, Brigitte C.

    2009-01-01

    Revealed preferences are tastes that rationalize an economic agent’s observed actions. Normative preferences represent the agent’s actual interests. It sometimes makes sense to assume that revealed preferences are identical to normative preferences. But there are many cases where this assumption is violated. We identify five factors that increase the likelihood of a disparity between revealed preferences and normative preferences: passive choice, complexity, limited personal experience, third-party marketing, and intertemporal choice. We then discuss six approaches that jointly contribute to the identification of normative preferences: structural estimation, active decisions, asymptotic choice, aggregated revealed preferences, reported preferences, and informed preferences. Each of these approaches uses consumer behavior to infer some property of normative preferences without equating revealed and normative preferences. We illustrate these issues with evidence from savings and investment outcomes. PMID:24761048

  9. Can Satellite Geodesy Disentangle Holocene Rebound and Present-Day Glacier Balance Signatures?

    NASA Technical Reports Server (NTRS)

    Irvins, E.; James, T.; Yoder, C.

    1995-01-01

    The secular drift of the precession of the ascending node of the LAGOES -1 satellite is apparently linked to the Earth s paleoclimate through the slow viscous response of the mantle to ice sheet/ocean mass transfer during the last great continental deglaciation . The secular node acceleration is particularly sensitive to the longest wavelengths of the paleo -surface loading that have been memorized by the mantle glacio -isostatic flow. Tide gauge records for the last 130 years show a post-glacial rebound-corrected sea-level rise of 2.4 n 0.9 mm yr-1.

  10. Possible changes in dust burden between present day and the end of the 21st century

    NASA Astrophysics Data System (ADS)

    Stanelle, Tanja; Bey, Isabelle

    2015-04-01

    Changes in climate and land cover significantly impact the emission and burden of dust particles. Due to the forecasted increase in greenhouse gas concentrations the climate is supposed to change. Especially changes in wind speed and precipitation have a huge effect on dust burden. Changes in climate may also impact the land cover in the coming decades. Additionally the land cover is supposed to be altered directly by humans due transformation of natural into agricultural vegetation (or agricultural into natural vegetation). These changes in land cover will change the distribution of areas where dust could be emitted. We use a version of our global climate-aerosol model ECHAM6-HAM that derives interactively potential dust sources (Stanelle et al., 2014) to give estimates about possible changes in dust burden between today and different future conditions. We based our simulation on 3 different future scenarios (rcp2.8, rcp4.5, rcp8.5) performed with the MPI-Earth system model during the CMIP5 project. References: Stanelle et al. (2014), Anthropogenically induced changes in twentieth century mineral dust burden and the associated impact on radiative forcing, J. Geophys. Res., 119, 13,526-13,546, doi:10.1002/2014JD022062.

  11. Digitization of the human body in the present-day economy

    NASA Astrophysics Data System (ADS)

    D'Apuzzo, Nicola

    2005-01-01

    In this paper we report on the historic development of human body digitization and on the actual state of commercially available technology. Complete systems for the digitization of the human body exist since more than ten years. One of the main users of this technology was the entertainment industry. Every new movie excited with attractive visual effects, but only few people knew that the most thrilling cuts were realized by using virtual persons. The faces and bodies of actors were digitized and the "virtual twin" replaced the actor in the movie. Nowadays, the state of the human body digitization is so high that it is not possible any more to distinguish the real actor from the virtual one. Indeed, for the rush technical development has to be thanked the movie industry, which was one of the strong economic motors for this technology. Today, with the possibility of a massive cost reduction given by new technologies, methods for digitization of the human body are used also in other fields of application, such as ergonomics, medical applications, computer games, biometry and anthropometrics. With the time, this technology becomes interesting also for sport, fitness, fashion and beauty. A large expansion of human body digitization is expected in the near future. To date, different technologies are used commercially for the measurement of the human body. They can be divided into three distinguished groups: laser-scanning, projection of light patterns, combination modeling and image processing. The different solutions have strengths and weaknesses that profile their suitability for specific applications. This paper gives an overview of their differences and characteristics and expresses clues for the selection of the adequate method. Practical examples of commercial exploitation of human body digitization are also presented and new interesting perspectives are introduced.

  12. Digitization of the human body in the present-day economy

    NASA Astrophysics Data System (ADS)

    D'Apuzzo, Nicola

    2004-12-01

    In this paper we report on the historic development of human body digitization and on the actual state of commercially available technology. Complete systems for the digitization of the human body exist since more than ten years. One of the main users of this technology was the entertainment industry. Every new movie excited with attractive visual effects, but only few people knew that the most thrilling cuts were realized by using virtual persons. The faces and bodies of actors were digitized and the "virtual twin" replaced the actor in the movie. Nowadays, the state of the human body digitization is so high that it is not possible any more to distinguish the real actor from the virtual one. Indeed, for the rush technical development has to be thanked the movie industry, which was one of the strong economic motors for this technology. Today, with the possibility of a massive cost reduction given by new technologies, methods for digitization of the human body are used also in other fields of application, such as ergonomics, medical applications, computer games, biometry and anthropometrics. With the time, this technology becomes interesting also for sport, fitness, fashion and beauty. A large expansion of human body digitization is expected in the near future. To date, different technologies are used commercially for the measurement of the human body. They can be divided into three distinguished groups: laser-scanning, projection of light patterns, combination modeling and image processing. The different solutions have strengths and weaknesses that profile their suitability for specific applications. This paper gives an overview of their differences and characteristics and expresses clues for the selection of the adequate method. Practical examples of commercial exploitation of human body digitization are also presented and new interesting perspectives are introduced.

  13. Competing bounds on the present-day time variation of fundamental constants

    SciTech Connect

    Dent, Thomas; Stern, Steffen; Wetterich, Christof

    2009-04-15

    We compare the sensitivity of a recent bound on time variation of the fine structure constant from optical clocks with bounds on time-varying fundamental constants from atomic clocks sensitive to the electron-to-proton mass ratio, from radioactive decay rates in meteorites, and from the Oklo natural reactor. Tests of the weak equivalence principle also lead to comparable bounds on present variations of constants. The 'winner in sensitivity' depends on what relations exist between the variations of different couplings in the standard model of particle physics, which may arise from the unification of gauge interactions. Weak equivalence principle tests are currently the most sensitive within unified scenarios. A detection of time variation in atomic clocks would favor dynamical dark energy and put strong constraints on the dynamics of a cosmological scalar field.

  14. Present-day kinematics of the Mediterranean: A comprehensive overview of GPS results

    NASA Astrophysics Data System (ADS)

    Nocquet, Jean-Mathieu

    2012-12-01

    I combine recently published GPS results to derive a geodetic horizontal velocity field consistent at the scale of the Mediterranean and the surrounding Alpine belts. The velocity field is then used to discuss the boundary conditions around each major deforming area in the Mediterranean, to describe the main patterns of motion and deformation, to critically review the existing kinematics models and to finally point out the main unresolved kinematics questions. Strain rate in Europe north of the Alpines belt is dominated by the signature of the Glacial Isostatic Adjustment and tectonic strain remains below the current accuracy of GPS results. In the western Mediterranean, deformation is restricted to the Betics, the Alboran and the Morrocan Rif, with west-to-southwestward motion with respect to Iberia, which is part of stable Europe. Shortening, consistent with the relative Nubia/Eurasia plate motion, is found throughout the Maghrebides, but the distribution of deformation in northern Africa remains largely unknown. The central Mediterranean is dominated by the counter-clockwise rotation of the Adriatic. The junction between the southern Adriatic domain and Nubia has yet to be firmly established. The deformation over a wide area, east of the Maghrebides, in Tunisia and the gulf of Sirte in Libya still remains to be quantified. In the eastern Mediterranean, the velocity field is dominated by a general anti-clockwise rotation and a general trend towards the Hellenic trench, with velocity magnitude increasing with decreasing distances from the trench. This trend is observed not only in the Aegean and Anatolia, but also in the southern Balkans. Geodetic results emphasize that the convergence of the Nubia and Arabia plates towards Eurasia directly controls the deformation across only very few segments along the plate boundary zone. Additional processes are therefore required to explain the observed velocity field and deformation pattern.

  15. Present day versus Temporal Heterogeneity of the Subridge Mantle in the Central Atlantic

    NASA Astrophysics Data System (ADS)

    Ligi, M.; Bonatti, E.; Brunelli, D.; Cipriani, A.

    2009-12-01

    Studies of MORB and of MORP (Mid Ocean Ridge Peridotite) show that the oceanic upper mantle is heterogeneous. Long and short wavelength chemical variability has been reported from the Mid Atlantic Ridge. The subridge mantle degree of melting, estimated from MORP mineral chemistry of mantle equilibrated spinel, opx and cpx, as well as from MORB glasses, decreases from the Azores swell at ~40ο N to the equator, in parallel to the decrease of crustal thickness inferred from the near zero-age Mantle Bouguer anomaly. The temporal evolution of this portion of a slow-spreading mid ocean ridge can be studied along seafloor spreading flowlines normal to ridge segments. A lithospheric section exposed between 10ο and 11ο N, south of the Vema Fracture Zone is giving us the opportunity to study how generation of lithosphere at a 80-km long ridge segment evolved since 25 Ma. Gravity data, and MORP-MORB chemistry correlations suggest a steady increase in crustal thickness and in mantle degree of melting from 20 Ma to Present, with superimposed 3-4 Ma oscillations. Variations of degree of melting, peridotite temperature of equilibration and crustal thickness are not proportional to spreading rate, suggesting variations in mantle source composition and a non-purely passive lithosphere formation at ridge axis. The combination of the zero-age axial ridge trend with the 20 Ma to Present trend could be explained by a subaxial hot/fertile mantle flow from the Azores swell toward an equatorial “cold” belt. The equatorial belt, characterized by long offset transforms, is magma starved and nearly free of basaltic crust. Small quantities of basalt, generated mostly in the garnet stability region by low degrees of partial melting, could not be expelled from the mantle, and froze to form a “constipated”, crust free lithosphere. Numerical calculations show a strong decrease of crustal production as a ridge approaches a transform, proportional to slip rate and offset length. When the amount of melt produced is small, the capability of melt to aggregate and to mix on the way to the surface is low; therefore, the chemical and isotopic signatures of preaggregated melts can be detected. Therefore, long-offset RTI's are potential areas to detect short-scale mantle heterogeneities through the study of MORB. Accordingly, basalts sampled in the equatorial Atlantic close to the Romanche transform, show an increase in trace element variability within a single dredge haul approaching the RTI, with wavelengths comparable to those observed in suites of melt inclusions. The correlation between MORB trace element and isotopic enrichement suggests that most of the chemical variability is due to source heterogeneity, rather than temperature.

  16. The Past as Prologue: Exploring the Historic Roots of Present Day Concerns in Early Childhood Education.

    ERIC Educational Resources Information Center

    Spodek, Bernard

    In contrast to a common set of roles or definitions, it is a common sense of mission that unifies practitioners in the field of early childhood education. Successful missions in time become transformed into organizational sagas that capture the allegiance and commitment of a group. Early childhood educators can increase their commitment to the…

  17. Water Isotopes in Precipitation: Data/Model Comparison for Present-Day and Past Climates

    NASA Technical Reports Server (NTRS)

    Jouzel, J.; Hoffmann, G.; Masson, V.

    1998-01-01

    Variations of HDO and H2O-18 concentrations are observed in precipitation both on a geographical and on a temporal basis. These variations, resulting from successive isotopic fractionation processes at each phase change of water during its atmospheric cycle, are well documented through the IAEA/WMO network and other sources. Isotope concentrations are, in middle and high latitudes, linearly related to the annual mean temperature at the precipitation site. Paleoclimatologists have used this relationship to infer paleotemperatures from isotope paleodata extractable from ice cores, deep groundwater and other such sources. For this application to be valid, however, the spatial relationship must also hold in time at a given location as the location undergoes a series of climatic changes. Progress in water isotope modeling aimed at examining and evaluating this assumption has been recently reviewed with a focus on polar regions and, more specifically, on Greenland. This article was largely based on the results obtained using the isotopic version of the NASA/GISS Atmospheric General Circulation Model (AGCM) fitted with isotope tracer diagnostics. We extend this review in comparing the results of two different isotopic AGCMs (NASA/GISS and ECHAM) and in examining, with a more global perspective, the validity of the above assumption, i.e. the equivalence of the spatial and temporal isotope-temperature relationship. We also examine recent progress made in modeling the relationship between the conditions prevailing in moisture source regions for precipitation and the deuterium-excess of that precipitation.

  18. [Dental insurance systems in light of present-day prevention potentials].

    PubMed

    Marthaler, T; Zollinger, E

    1979-05-01

    The situation of public dental insurance systems of several countries in Western Europe was examined in the light of the fact that caries and periodontitis may be prevented. Available epidemiological data were discussed as to their relevance. In Switzerland, dental insurance systems are of minor importance. In voluntary insurance plans for adults, prevention is scarcely included. On the other hand, the communities provide subsidies for dental care of schoolchildren, and prevention is an integral part of this system. In the German Federal Republic, dental insurance costs have quadrupled during the period 1970-1977. Preventive measures are not subsidized, and in recent years, more than half of the insurance payments were used for prosthetic dentistry. The few dental statistics available show that dental treatment of children is unsatisfactory. In Sweden, preventive measures are refunded at 75%. Since the introduction of the public insurance system in 1974 prosthetic dental work has increased at the expense of conservative treatment. In France, the social security system pays for about three quarters of conservative and simple prosthetic work. Prevention has so far not been included. Despite liberal refunding of restorative work markedly higher prevalence of tooth loss was found in lower social levels as compared to higher levels. In Great Britain, the National Health Service was introduced in 1948. As in France, tooth loss is most frequent in lower social levels. The findings are discussed with respect to cost developments and oral health prospects in Switzerland. Attention is focused upon the observation that the insurance systems were conceived at a time when realistic preventive programs were unavailable and their success had not yet been demonstrated in large groups. PMID:293044

  19. Modeling soluble salt assemblages on Mars: past aqueous history and present-day habitability

    NASA Astrophysics Data System (ADS)

    Toner, J. D.; Catling, D. C.; Light, B.

    2014-12-01

    Soluble salt assemblages formed through aqueous processes are widespread on Mars. These minerals are important for understanding the past aqueous history of Mars and indicate critical habitability parameters such as pH, temperature, water activity, and salinity. Equilibrium models have been used to determine solution chemistry and salt precipitation sequences from aqueous chemical data; however, current models are limited by a lack of experimental data for low-temperature perchlorates, and some model predictions are clearly anomalous. To address the need for accurate equilibrium models, we have developed a comprehensive model for low-temperature perchlorate-rich brines using (1) previously neglected literature data, (2) experimental solubilities determined in low-temperature perchlorate solutions, and (3) solubility and heat capacity results determined using Differential Scanning Calorimetry (DSC). Our resulting model is a significant improvement over existing models, such as FREZCHEM, particularly for perchlorate mixtures. We have applied our model to evaporation and freezing of a nominal Wet Chemistry Laboratory (WCL) solution measured at the Phoenix site. For a freezing WCL solution, our model indicates that ice, KClO4, hydromagnesite (3MgCO3·Mg(OH)2·3H2O), calcite (CaCO3), meridianiite (MgSO4·11H2O), MgCl2·12H2O, NaClO4·2H2O, and Mg(ClO4)2·6H2O form at the eutectic (209 K); whereas, KClO4, hydromagnesite, kieserite (MgSO4·H2O), anhydrite (CaSO4), halite (NaCl), NaClO4·H2O, and Mg(ClO4)2·6H2O form upon complete evaporation at 298 K. In general, evaporation yields more dehydrated mineral assemblages than salts produced by freezing. Hydrated phases that form during evaporation contain 0.3 wt. % water, which compares with 1.2 wt. % during freezing. Given independent evidence for the presence of calcite and minimum water contents in Martian soils of ~1.5 wt. %, salts at the Phoenix site, and possibly elsewhere, appear more likely to have formed during freezing. Furthermore, our model indicates that some minerals, such as halite, kieserite, epsomite, and mirabilite (Na2SO4·10H2O) form only under limited temperature and water activity conditions, and could be used to constrain the past aqueous history of Mars.

  20. Dental Stigmata of Congenital Syphilis: A Historic Review With Present Day Relevance.

    PubMed

    Nissanka-Jayasuriya, Eranga H; Odell, Edward W; Phillips, Carina

    2016-09-01

    Syphilis was the first sexually transmitted disease to be diagnosed in childhood. Most developed countries controlled syphilis effectively after the 1950s and congenital syphilis became rare. Since the late 1990s there has been a resurgence of syphilis in developed and developing countries and the WHO estimates that at least half a million infants die of congenital syphilis every year. The earliest reference to the dental manifestations of congenital syphilis was by Sir Jonathan Hutchinson, Assistant Surgeon at The London Hospital in 1861. Three main dental defects are described in congenital syphilis; Hutchinson's incisors, Moon's molars or bud molars, and Fournier's molars or mulberry molars. Although many physicians, dentists, and pathologists in developed countries will be aware of the dental features of syphilis, most will never have seen a case or made the diagnosis. The purpose of this article is to review some of the history of congenital syphilis, remind healthcare professionals of the features, and bring to their attention that the changes are still prevalent and that milder cases can be mistaken for other causes of hypoplasia. PMID:26897633

  1. Microbial Diversity Analysis of the Bacterial and Archaeal Population in Present Day Stromatolites

    NASA Technical Reports Server (NTRS)

    Ortega, Maya C.

    2011-01-01

    Stromatolites are layered sedimentary structures resulting from microbial mat communities that remove carbon dioxide from their environment and biomineralize it as calcium carbonate. Although prevalent in the fossil record, stromatolites are rare in the modem world and are only found in a few locations including Highbome Cay in the Bahamas. The stromatolites found at this shallow marine site are analogs to ancient microbial mat ecosystems abundant in the Precambrian period on ancient Earth. To understand how stromatolites form and develop, it is important to identify what microorganisms are present in these mats, and how these microbes contribute to geological structure. These results will provide insight into the molecular and geochemical processes of microbial communities that prevailed on ancient Earth. Since stromatolites are formed by lithifying microbial mats that are able to mineralize calcium carbonate, understanding the biological mechanisms involved may lead to the development of carbon sequestration technologies that will be applicable in human spaceflight, as well as improve our understanding of global climate and its sustainability. The objective of my project was to analyze the archaeal and bacterial dIversity in stromatolites from Highborn Cay in the Bahamas. The first step in studying the molecular processes that the microorganisms carry out is to ascertain the microbial complexity within the mats, which includes identifying and estimating the numbers of different microbes that comprise these mats.

  2. Acceptance or refusal of convenience food in present-day prison.

    PubMed

    Vanhouche, An-Sofie

    2015-11-01

    Food in prison is an insufficiently researched topic. However, prisoners often highlight problems with and criticism of their prison meals. This article aims to further develop this topic by giving closer insight into the use and attitudes toward ready-made meals in the Tilburg prison. In this prison, prisoners receive ready-made meals. This is in contrast to Belgian prisons, from which they were transferred, where meals were made from scratch. This change in the food system led to commotion and complaints. To understand the situation, interviews with prisoners and staff were conducted and observations in the Tilburg prison were made. The results showed that a food system can have considerable influence on prison experiences. In addition, and contrary to what earlier reports have mentioned, the ready-made meals also have some advantages, especially for the organization of daily prison life. However, most prisoners had negative attitudes toward these meals. PMID:25891041

  3. Computational approach for investigation of thrust and acoustic performances of present-day nozzles

    NASA Astrophysics Data System (ADS)

    Vlasenko, V.; Bosniakov, S.; Mikhailov, S.; Morozov, A.; Troshin, A.

    2010-05-01

    A computational viewpoint on the problems of design and numerical simulation for the nozzles of modern aircraft turbofan engines is presented. Modern concepts of noise-suppressing nozzles for civil aircraft are reviewed. Examples of application of CFD (computational fluid dynamics) methods to the analysis of nozzle flow structure and assessment of nozzle thrust characteristics are given. Errors of turbulence models in simulation of jets are analyzed. The authors’ experience in simulation of noise-suppressing nozzles for supersonic civil aircrafts is demonstrated. Insufficient accuracy of acoustic analogies for this class of tasks is shown, but a possible area of acoustic analogies application is noted. The essential elements of computational aeroacoustics (CAA) approach and numerical methods characteristic of CAA are reviewed. Numerical methodology for the simulation of nozzle acoustic performance is described in detail, including methods for simulation of near and far field of a nozzle, for generation of input perturbations and for the processing the far-field noise. Results of verification and methodical analysis of this acoustic methodology are presented.

  4. Present-day formation and seasonal evolution of linear dune gullies on Mars

    NASA Astrophysics Data System (ADS)

    Pasquon, Kelly; Gargani, Julien; Massé, Marion; Conway, Susan J.

    2016-08-01

    Linear dune gullies are a sub-type of martian gullies. As their name suggests they only occur on sandy substrates and comprise very long (compared to their width) straight or sinuous channels, with relatively small source areas and almost non-existent visible deposits. Linear dune gullies have never been observed on terrestrial dunes and their formation process on Mars is unclear. Here, we present the results of the first systematic survey of these features in Mars' southern hemisphere and an in-depth study of six dunefields where repeat-imaging allows us to monitor the changes in these gullies over time. This study was undertaken with HiRISE images at 25-30 cm/pix and 1 m/pix elevation data derived from HiRISE stereo images. We find the latitudinal distribution and orientation of linear dune gullies broadly consistent with the general population of martian gullies. They occur predominantly between 36.3°S and 54.3°S, and occasionally between 64.6°S and 70.4°S. They are generally oriented toward SSW (at bearings between 150° and 260°). We find that these gullies are extremely active over the most recent 5 Martian years of images. Activity comprises: (1) appearance of new channels, (2) lengthening of existing channels, (3) complete or partial reactivation, and (4) disappearance of gullies. We find that gully channels lengthen by ∼100 m per year. The intense activity and the progressive disappearance of linear dune gullies argues against the hypothesis that these are remnant morphologies left over from previous periods of high obliquity millions of years ago. The activity of linear dune gullies reoccurs every year between the end of winter and the beginning of spring (Ls 167.4°-216.6°), and coincides with the final stages of the sublimation of annual CO" ice deposit. This activity often coincides spatially and temporally with the appearance of recurrent diffusing flows (RDFs)-digitate-shaped, dark patches with low relative albedo (up to 48% lower than the adjacent dune) that encompass the active site. South- and SSW-facing dune slopes are those which preferentially host CO2 frost deposits, however, it is only those with angles of ∼20° just below the crest which possess linear dune gullies, suggesting a slope-limited formation process. These observations provide a wealth of temporal and morphometric data that can be used to undertake numerical modeling, to direct future image monitoring and guide laboratory experiments that can be used to better constrain the formation process of these features.

  5. Methodological Problems of the Present-Day Sociology of Education: A Roundtable

    ERIC Educational Resources Information Center

    Russian Education and Society, 2011

    2011-01-01

    An all-Russian conference on "Education and Society" was held on 22 October 2009 at the Academy of Labor and Social Relations, in the course of which roundtables were conducted with leading representatives of Russian sociological science. The conference was timed to coincide with the twentieth anniversary of the founding of the Russian Society of…

  6. Discovery of Five Candidates for Present Day η Carinae Analogs in Nearby Galaxies

    NASA Astrophysics Data System (ADS)

    Khan, Rubab M.

    2016-01-01

    Late-stage evolution of the most massive stars such as η Carinae is controlled by the effects of mass loss, possibly dominated by poorly understood episodic mass ejections. Through a systematic search utilizing archival Spitzer and HST data, we have discovered five objects in the nearby (<10 Mpc) massive star-forming galaxies M51, M83, M101 and NGC6946 that have optical through mid-infrared photometric properties consistent with their being analogs of the hitherto unique η Car as it is presently observed. Prior to this discovery there were no known analogs of η Car either in our or other galaxies. These objects are very luminous, with Lbol=3-6×106 L⊙. Their Spitzer mid-infrared spectral energy distributions rise steeply in the 3.6-8 μm bands, then turn over between 8 and 24 μm indicating the presence of warm (~400-600 K) circumstellar dust. Their optical counterparts, identified in deep HST images, are 1.5-2 dex fainter relative to mid-IR peaks and require the presence of ~5-10 M⊙ obscuring material. We present the properties of these five sources and discuss the implications of our discovery for understanding massive star evolution.

  7. Historical Epidemiology of the Second Cholera Pandemic: Relevance to Present Day Disease Dynamics

    PubMed Central

    Chan, Christina H.; Tuite, Ashleigh R.; Fisman, David N.

    2013-01-01

    Despite nearly two centuries of study, the fundamental transmission dynamic properties of cholera remain incompletely characterized. We used historical time-series data on the spread of cholera in twelve European and North American cities during the second cholera pandemic, as reported in Amariah Brigham’s 1832 A Treatise on Epidemic Cholera, to parameterize simple mathematical models of cholera transmission. Richards growth models were used to derive estimates of the basic reproductive number (R0) (median: 16.0, range: 1.9 to 550.9) and the proportion of unrecognized cases (mean: 96.3%, SD: 0.04%). Heterogeneity in model-generated R0 estimates was consistent with variability in cholera dynamics described by contemporary investigators and may represent differences in the nature of cholera spread. While subject to limitations associated with measurement and the absence of microbiological diagnosis, historical epidemic data are a potentially rich source for understanding pathogen dynamics in the absence of control measures, particularly when used in conjunction with simple and readily interpretable mathematical models. PMID:23991117

  8. Charting the Y-chromosome ancestry of present-day Argentinean Mennonites.

    PubMed

    Toscanini, Ulises; Brisighelli, Francesca; Llull, Cintia; Berardi, Gabriela; Gómez, Andrea; Andreatta, Fernando; Pardo-Seco, Jacobo; Gómez-Carballa, Alberto; Martinón-Torres, Federico; Álvarez-Iglesias, Vanesa; Salas, Antonio

    2016-06-01

    Old Order Mennonite communities initially arose in Northern Europe (centered in the Netherlands) and derived from the Anabaptist movement of the 16th century. Mennonites migrated to the New World in the early 18th century, first to North America, and more recently to Mesoamerica and South America. We analyzed Y-chromosome short tandem repeats (STRs) and single nucleotide polymorphisms in males from a community of Mennonites, 'La Nueva Esperanza', which arrived to Argentina in 1985 from colonies in Bolivia and Mexico. Molecular diversity indices coupled with demographic simulations show that Mennonites have a reduced variability when compared with local Argentinean populations and 69 European population samples. Mennonite Y-STR haplotypes were mainly observed in Central Europe. In agreement, multidimensional scaling analyses based on RST genetic distances indicate that Mennonite Y-chromosomes are closely related to Central/Northern Europeans (the Netherlands, Switzerland and Denmark). In addition, statistical inferences made on the most likely geographic origin of Y-chromosome haplotypes point more specifically to the Netherlands as the populations that best represent the majority of the Mennonite Y-chromosomes. Overall, Y-chromosome variation of Mennonites shows the signatures of moderate reduction of variability when compared with source populations, which is in good agreement with their lifestyle in small endogamous demes. These genetic singularities could also help to understand disease conditions that are more prevalent among Mennonites. PMID:26841831

  9. Climatology and temporal evolution of the atmospheric semidiurnal tide in present-day reanalyses

    NASA Astrophysics Data System (ADS)

    Díaz-Argandoña, J.; Ezcurra, A.; Sáenz, J.; Ibarra-Berastegi, G.; Errasti, I.

    2016-05-01

    The solar semidiurnal atmospheric tide (S2) was extracted from seven reanalysis data sets, including current data sets, such as CFSR (Climate Forecast System Reanalysis), MERRA (Modern-Era Retrospective Analysis for Research and Applications), ERA-Interim (ECMWF Reanalysis), and 20CR (Twentieth Century Reanalysis), and older frozen products, such as NCEP/NCAR (National Center for Environmental Prediction/National Center for Atmospheric Research), ERA-40 (ECMWF Reanalysis), and JRA-25 (Japanese 25 year Reanalysis). In this calculation, we emphasized the temporal variation of the tide. We also calculated the tidal error, which was sizable at high latitudes and over short averaging periods and large for 20CR at all latitudes. Because of the four standard daily samples, the interpolation scheme of van den Dool et al. (1997) was used when necessary. We found this method to be accurate for zonally averaged tides only. Comparing the climatology from the MERRA and CFSR S2 with a recent empirical tide model showed that MERRA better represented the geographical structure of the tide, especially its phase. We found a bias in the phase in all of the reanalysis data sets except for MERRA. The temporal evolution of the tide was inconsistent between the different data sets, although similar seasonal variations were observed. The seasonal cycle was also better depicted in MERRA. The S2 calculated from MERRA and satellite precipitation measurements from TRMM (Tropical Rainfall Measuring Mission) presented results that were inconsistent with the hypothesis in which rainfall latent heat release represents S2 forcing and functions as a source of S2 seasonal variability.

  10. They're Alive! Present-Day Evolution of Martian Dunes

    NASA Technical Reports Server (NTRS)

    Diniega, S.; Bridges, N.; Hansen, C.

    2011-01-01

    The sharp brinks and margins, smooth and steep lee slopes, and lack of superimposed landforms (such as small impact craters) on many Martian sand dunes suggests that these features are geologically young clean brinks and smooth/steep lee slopes (HiRISE image PSP_010413_1920; 20 deg N,79 deg E; image widthis about 500m).Within the last decade, and often primarily through the detailed inspection of high-resolution (HiRISE) images, we have finally found clear evidence that many dunes of Mars are active -- through both aeolian and seasonal (frost) processes. However, it is yet unclear if active dune formation does occur or if we are observing surficial modification of dunes which formed under different climate conditions.

  11. Present-day Halimeda carbonate sediments in temperate mediterranean embayments: Fornells, Balearic Islands

    NASA Astrophysics Data System (ADS)

    Fornos, J. J.; Forteza, V.; Jaume, C.; Martinez-Taberner, A.

    1992-01-01

    Fornells Bay is an enclosed embayment located in the north of the Balearic Platform in the Western Mediterranean. It displays bioelastic sedimentation with strong terrigenous influences. The plant communities responsible for the carbonate sediment input are the seagrasses Posidonia oceanica and Cymodocea nodosa, and red and green algae, the most important of which is Halimeda tuna. The distribution of the latter is clearly related to bathymetry and it forms the principal bioclastic component ( > 40%) in shallow sediments (0-25 m). Red algae are found below 30 m with a characteristic branching coralline algae sea floor. Organic matter in the finest-grained facies attains 6.59%. The bay exhibits a hydrodynamic gradient from low in the interior where there is a terrigenous influence to high in the outer open marine sectors. The presence of Halimeda-rich carbonates and fine-grained terrigenous sediments within Balearic embayments provides an example of Chloralgal facies in a region where Foramol would have been expected. The system described provides new data for the interpretation of fossil temperate-water carbonates.

  12. Present-day stress field in subduction zones: Insights from 3D viscoelastic models and data

    NASA Astrophysics Data System (ADS)

    Petricca, Patrizio; Carminati, Eugenio

    2016-01-01

    3D viscoelastic FE models were performed to investigate the impact of geometry and kinematics on the lithospheric stress in convergent margins. Generic geometries were designed in order to resemble natural subduction. Our model predictions mirror the results of previous 2D models concerning the effects of lithosphere-mantle relative flow on stress regimes, and allow a better understanding of the lateral variability of the stress field. In particular, in both upper and lower plates, stress axes orientations depend on the adopted geometry and axes rotations occur following the trench shape. Generally stress axes are oriented perpendicular or parallel to the trench, with the exception of the slab lateral tips where rotations occur. Overall compression results in the upper plate when convergence rate is faster than mantle flow rate, suggesting a major role for convergence. In the slab, along-strike tension occurs at intermediate and deeper depths (> 100 km) in case of mantle flow sustaining the sinking lithosphere and slab convex geometry facing mantle flow or in case of opposing mantle flow and slab concave geometry facing mantle flow. Along-strike compression is predicted in case of sustaining mantle flow and concave slabs or in case of opposing mantle flow and convex slabs. The slab stress field is thus controlled by the direction of impact of mantle flow onto the slab and by slab longitudinal curvature. Slab pull produces not only tension in the bending region of subducted plate but also compression where upper and lower plates are coupled. A qualitative comparison between results and data in selected subductions indicates good match for South America, Mariana and Tonga-Kermadec subductions. Discrepancies, as for Sumatra-Java, emerge due to missing geometric (e.g., occurrence of fault systems and local changes in the orientation of plate boundaries) and rheological (e.g., plasticity associated with slab bending, anisotropy) complexities in the models.

  13. Independent Review of Simulation of Net Infiltration for Present-Day and Potential Future Climates

    SciTech Connect

    Review Panel: Soroosh Sorooshian, Ph.D., Panel Chairperson, University of California, Irvine; Jan M. H. Hendrickx, Ph.D., New Mexico Institute of Mining and Technology; Binayak P. Mohanty, Ph.D., Texas A&M University; Scott W. Tyler, Ph.D., University of Nevada, Reno; Tian-Chyi Jim Yeh, Ph.D., University of Arizona -- ORISE Review Facilitators: Robert S. Turner, Ph.D., Technical Review Group Manager, Oak Ridge Institute for Science and Education; Brian R. Herndon, Project Manager, Oak Ridge Institute for Science and Education; Russ Manning, Technical Writer /Editor, Haselwood Enterprises, Inc.

    2008-08-30

    The DOE Office of Civilian Radioactive Waste Management (OCRWM) tasked Oak Ridge Institute for Science and Education (ORISE) with providing an independent expert review of the documented model and prediction results for net infiltration of water into the unsaturated zone at Yucca Mountain. The specific purpose of the model, as documented in the report MDL-NBS-HS-000023, Rev. 01, is “to provide a spatial representation, including epistemic and aleatory uncertainty, of the predicted mean annual net infiltration at the Yucca Mountain site ...” (p. 1-1) The expert review panel assembled by ORISE concluded that the model report does not provide a technically credible spatial representation of net infiltration at Yucca Mountain. Specifically, the ORISE Review Panel found that: • A critical lack of site-specific meteorological, surface, and subsurface information prevents verification of (i) the net infiltration estimates, (ii) the uncertainty estimates of parameters caused by their spatial variability, and (iii) the assumptions used by the modelers (ranges and distributions) for the characterization of parameters. The paucity of site-specific data used by the modeling team for model implementation and validation is a major deficiency in this effort. • The model does not incorporate at least one potentially important hydrologic process. Subsurface lateral flow is not accounted for by the model, and the assumption that the effect of subsurface lateral flow is negligible is not adequately justified. This issue is especially critical for the wetter climate periods. This omission may be one reason the model results appear to underestimate net infiltration beneath wash environments and therefore imprecisely represent the spatial variability of net infiltration. • While the model uses assumptions consistently, such as uniform soil depths and a constant vegetation rooting depth, such assumptions may not be appropriate for this net infiltration simulation because they oversimplify a complex landscape and associated hydrologic processes, especially since the model assumptions have not been adequately corroborated by field and laboratory observations at Yucca Mountain.

  14. [Present-day hygienic aspects of dealing with industrial and consumption waste].

    PubMed

    Gil'denskiol'd, R S; Kur'ianova, I S

    2005-01-01

    The article covers scientific hygienic positions in forming and solving the acute scientific and technical problem of dealing with waste. The given problem is topical due to growing amount and diversity of waste and relatively small knowledge of ecological, medical and biological aspects of the problem. The paper covers the entire "life cycle" of waste, chiefly industrial and communal, as the most diverse and potentially dangerous to the environment. Special attention is paid to neutralization and recycling of waste for its application as secondary material in various branches of national economy. Having critically analized the results of complex studies, the authors conclude the article with outlining the prospective tasks of research for scientific and practical institutions of sanitary surveillance of Russian Federation Ministry of Health. PMID:15852717

  15. Inception of cadaver dissection and its relevance in present day scenario of medical education.

    PubMed

    Rath, Gayatri; Garg, Krishna

    2006-06-01

    The concept of dissection for acquiring knowledge about the structure of human body was started in 15th century and barber--surgeons used to demonstrate various structures at the professors command. Andreas Vesalius (1514-1564) was the first medical student to dissect the cadaver and also continued with it even as a professor. Slowly and steadily its importance was realised. Once autopsy was accepted as a ideal parameter to establish the causes of death, the importance of dissection got enhanced. Cadavers were obtained earlier from the grave robbings and mortuaries, which was followed by, an Anatomy Act of 1832, by which unclaimed bodies were provided to the anatomy department. For last two decades, many persons started donating their bodies to the department of anatomy. In India, mostly unclaimed bodies are handed over to anatomy department for teaching and research purpose. Cadavers teach students during 1st professional course, autopsy teaches again in IInd and IIIrd professional courses and even later on throughout the career. Dissection helps in developing a spatial and tactile appreciation for the fabric of the human body that cannot be achieved by prosection or computerised learning aids alone. PMID:17058553

  16. Scandinavian postglacial faults and their physical connection to present day seismicity

    NASA Astrophysics Data System (ADS)

    Arvidsson, R.

    2015-12-01

    In Scandinavia large earthquakes up to M~8.2 occurred 9500 yBP due to rapid deglaciation leaving fault scarps with lengths up to 160km and vertical offsets of at least 10 m. Today a lion share of local earthquakes are located to the vicinity of the faults. I show here from Coulomb failure stress modeling a physical connection between clustering of recent earthquakes and high Coulomb failure stresses around the faults. This can be interpreted In such a fashion that the location of the current earthquakes resembles locations of aftershock sequences. The explanation is that when these faults where formed it was due to state of stress in the crust at time of deglaciation, different from today's conditions. The crust was heavily depressed at deglaciation about 250 m in the region and due of the receding icesheet the crust was subjected to high stresses resulting in fault motion. This fault motion occurred in order to minimize state of stress at deglaciation. However, this state of stress has since changed with the regional postglacial uplift and thus today these faults remain as perturbations in the crust with concentrations of high stresses. I elaborate on this mechanism. I also advocate that this correlation between high stressed fault areas and locations of earthquakes indicates that seismicity within stable continental regions like Scandinavia might be caused by previous crustal disturbances that show local perturbations of the stress field. Therefore if faults are favorably oriented in the present stress field they can be released by brittle earthquake faulting . Thus past transient tectonic events can explain part of the stable continental region's seismicity. This may be of large importance to assessment of seismic hazard within stable continental regions particularly for critical structures like e.g., nuclear waste deposits and hydroelectric dams.

  17. Simulation of present-day precipitation over India using a regional climate model

    NASA Astrophysics Data System (ADS)

    Maurya, Rajesh Kumar Singh; Singh, G. P.

    2016-04-01

    The objective of the present paper is to examine the capability of the regional climate model version 3 (RegCM3) to simulate the annual as well as seasonal precipitation variability over the Indian subcontinent. RegCM3 has been run at 40 km horizontal resolution for the period of 1982-2006 continuously and model results were compared to the observed precipitation datasets of India Meteorological Department (IMD) and CPC Merged Analysis of Precipitation (CMAP). Model evaluation has been done using different statistical methods like mean bias error (MBE), root mean square error, mean percentage error (MPE) and studied the spatial pattern of annual and seasonal variability and trend. Daily precipitation data at 1° × 1° grids of IMD have been used to study observed climatological means (both annual and seasonal), regression trends, interannual and intraseasonal variability over India from 1951 to 2007. The spatial distribution of annual precipitation shows a decreasing trend over west coast of India, central India, hilly region of India and an increasing trend is found over the northwest India, peninsular India and northeast India. The temporal distribution of daily precipitation shows highest rainfall of 18 mm/day in mid July (in composite flood cases only) and 12 mm/day during August (in composite drought cases only). The RegCM3 simulated annual and seasonal precipitation variability is close to the observed IMD and CMAP over all India (AI). During winter and pre-monsoon season, the model has overestimated the mean precipitation while underestimated in summer and post-monsoon season. Overall, annual precipitation showed the deficiency of -22.44 % compared to IMD and -1.41 % compared to CMAP over India. To understand the possible cause of annual and seasonal precipitation biases over India and its six homogeneous regions, the vertical difference (model mines National Centre for Environmental Prediction; NCEP) fields of water vapor mixing ratio (WVMR) and air temperature from surface to top level (1 σ-18 σ level) have been studied in detail. The model produced more moisture at the lower level during winter (JF) and pre-monsoon (MAM) season and reduced WVMR at the same levels during summer (JJAS) and post (OND) monsoon over India. High moisture content at the lower level simulated in the model can explain the increased precipitation during JF and MAM season and vice versa during JJAS and OND. Similar results were found over the homogeneous regions of India. This analysis indicates that the RegCM3 has more transport of vertical WVMR from surface to mid layer of the troposphere compared to NCEP.

  18. Kinematic interpretation of present-day crustal deformation in central Greece from continuous GPS measurements

    NASA Astrophysics Data System (ADS)

    Chousianitis, Konstantinos; Ganas, Athanassios; Gianniou, Michail

    2013-11-01

    We processed 30-s GPS data from continuous GPS stations in central Greece using the Kalman filtering approach and accounting for time-correlated noise content obtaining a velocity field in the ITRF2008 and the Eurasian-fixed reference frame. The station distribution allowed us to compute 1D strain through rates of baseline length changes as well as to construct the image of the 2D strain and rotation rate fields. The obtained baselines range in length from 11 to 132 km and show rates from -1.95 mm/yr up to 14.14 mm/yr (estimated uncertainties from 0.3 to 0.8 mm/yr), while the calculated 1D strain rate ranges from -27 ns/yr up to 226 ns/yr (average uncertainty ˜15 ns/yr). Largest extension (192-226 ns/yr) is observed in the western and central part of the Corinth rift while similar extension rates (80-120 ns/yr) are obtained for the eastern part of the Corinth rift and its continuation in the south Viotia-south of Evia region and across the Sperchios-Kammena Vourla rift. The coherent picture of the velocity pattern for Attica and north-eastern Peloponnese (Corinth) stations indicates that these areas belong to the same crustal block, separating by the Viotia region by a nearly E-W crustal discontinuity along the Kaparelli-Asopos valley faults. However, some internal strain is present within Attica's crust as well as across the Saronic Gulf resulting in extension rates of the order of 25 ns/yr. We also find extension (54-71 ns/yr) across "rigid" Peloponnese taken by normal faults in the greater Kalavryta region.

  19. How Many Hotspots are on Present-day Earth, and are all Plumes hot?

    NASA Astrophysics Data System (ADS)

    Herzberg, C.

    2004-12-01

    The petrological characteristics of primary magmas that exit the melting regime are sensitive indicators of mantle potential temperature. However, most primary magmas partially crystallize some olivine during transit to the surface, and erupted lavas are typically hybrid mixtures of olivine and solidified liquid. Primitive glass on the surface can have an MgO content that is lower than a parental magma from which it was derived, and a parental magma can differ from its primary magma by partial crystallization of olivine in a crustal magma chamber. However, the parental magma composition can be restored using a simple petrological procedure when olivine is the sole phenocryst phase. On Kilauea the most primitive magnesian glass has been reported to contain 15% MgO, and the most magnesian olivines contain Fo 90-91. The exchange coefficients (Kd) for FeO and MgO between these olivine and glass compositions are 0.25-0.28, much lower than 0.33-0.34 for olivine equilibrated with liquid in melting experiments. The only way to obtain the correct Kd is by computing the effects of dissolving olivine into a 15% MgO liquid composition. This procedure results in a crustal parental magma with 17-19% MgO and a mantle primary magma with 18-20% MgO. The potential crystallization temperature for Kilauea is 1400C, an estimate that includes the effects of 0.34% H2O. Hawaii is therefore a hotspot. This is the most fundamental geological constraint that all models are required to satisfy. It is independent of ongoing questions concerning the role of subducted crust and pyroxenite in the melting regime. A primary magma with 18-20% MgO is successfully reproduced by decompression melting in a hot plume with potential temperatures in excess of 1550C. Hawaii is the only hotspot Earth at the present time. The mantle below Iceland is comparatively cooler, warmer than oceanic ridges, but it was hotter during the early Tertiary. A preliminary analysis of volcanics in and around the African and South Pacific superplumes indicates low extents of wet melting and potential temperatures that may be comparable to oceanic ridges (~1300-1400C). More work is needed for a quantitative petrological evaluation, but it is clear that these volcanoes cannot be hotspots even though they are associated with broad and narrow regions of slow seismic velocities that extend deep into the mantle. The implication is that most plumes or superplumes are buoyant for compositional reasons at or close to ambient mantle temperatures, and they are distinct from the Hawaiian hotspot.

  20. The chlorine budget of the present-day atmosphere - A modeling study

    NASA Technical Reports Server (NTRS)

    Weisenstein, Debra K.; Ko, Malcolm K. W.; Sze, Nien-Dak

    1992-01-01

    The contribution of source gases to the total amount of inorganic chlorine (ClY) is examined analytically with a time-dependent model employing 11 source gases. The source-gas emission data are described, and the modeling methodology is set forth with attention given to the data interpretation. The abundances and distributions are obtained for all 11 source gases with corresponding ClY production rates and mixing ratios. It is shown that the ClY production rate and the ClY mixing ratio for each source gas are spatially dependent, and the change in the relative contributions from 1950 to 1990 is given. Ozone changes in the past decade are characterized by losses in the polar and midlatitude lower stratosphere. The values for CFC-11, CCl4, and CH3CCl3 suggest that they are more evident in the lower stratosphere than is suggested by steady-state estimates based on surface concentrations.

  1. Effects of present-day deglaciation in Iceland on mantle melt production rates

    NASA Astrophysics Data System (ADS)

    Schmidt, P.; Lund, B.; Hieronymus, C.; Maclennan, J.; Árnadóttir, T.; Pagli, C.

    2013-07-01

    Ongoing deglaciation in Iceland not only causes uplift at the surface but also increases magma production at depth due to decompression of the mantle. Here we study glacially induced decompression melting using 3-D models of glacial isostatic adjustment in Iceland since 1890. We find that the mean glacially induced pressure rate of change in the mantle increases melt production rates by 100-135%, or an additional 0.21-0.23 km3 of magma per year beneath Iceland. Approximately 50% of this melt is produced underneath central Iceland. The greatest volumetric increase is found directly beneath Iceland's largest ice cap, Vatnajökull, colocated with the most productive volcanoes. Our models of the effect of deglaciation on mantle melting predict a significantly larger volumetric response than previous models which only considered the effect of deglaciation of Vatnajökull, and only mantle melting directly below Vatnajökull. Although the ongoing deglaciation significantly increases the melt production rate, the increase in melt supply rate at the base of the lithosphere is delayed and depends on the melt ascent velocity through the mantle. Assuming that 25% of the melt reaches the surface, the upper limit on our deglaciation-induced melt estimates for central Iceland would be equivalent to an eruption the size of the 2010 Eyjafjallajökull summit eruption every seventh year.

  2. Present-Day Deformation in Northeastern California, Northwest Nevada and Southern Oregon

    NASA Astrophysics Data System (ADS)

    Thatcher, W. R.; Svarc, J. L.; Lisowski, M.

    2014-12-01

    We use a newly expanded Global Positioning System (GPS) network in NE California, NW Nevada, and southern Oregon to estimate block rotation rates, slip rates on faults and internal block strain rates. The horizontal velocity field comprises 105 USGS campaign GPS sites surveyed during 1999-2014 and have velocity uncertainties less than 1 mm/yr, augmented by 21 continuous Plate Boundary Observatory sites operated since 2005. Sites near Mt. Shasta and Lassen volcanoes are excluded from the analysis to eliminate possible episodic magmatic deformation but stations near Medicine Lake Caldera are corrected for the known source of steady-state subsidence and local contraction. Most of the observed velocity field can be explained by counter-clockwise block rotation of ~0.3 deg/Ma about a pole located in northern Idaho and internal strain rates of < 20 ns/a. Slip rates on the known major extension faults (Surprise Valley, Klamath Graben, Goose Lake, and Hat Creek) are low, less than ~ 1 mm/yr. An earlier estimate of ~ 3 mm/yr of horizontal extension across the Hat Creek fault (Thatcher and Svarc, 2010 AGU) is not supported by the more accurate and spatially dense velocity field examined here.

  3. Shot noise: from Schottky's vacuum tube to present-day quantum devices

    NASA Astrophysics Data System (ADS)

    Schonenberger, Christian; Oberholzer, Stefan

    2004-05-01

    Shot-noise in the electrical current through a 'device' is caused by random processes that determine the electron transport from source to drain. Two sources can be distinguished: on the hand, electrons may randomly emanate from the contacts (source and drain), because the relevant states in the reservoirs fluctuate. On the other hand, the transmission through the device is non-deterministic (non-classical). As we demonstrate in this article the former dominates noise in the vacuum tube, whereas the latter applies to coherent mesoscopic devices, which have been studied in great detail during the last decade.

  4. Specific allogeneic unresponsiveness in the adult host: present-day experimental models

    SciTech Connect

    Rapaport, F.T.; Bachvaroff, R.J.; Cronkite, E.; Chanana, A.; Sato, T.; Asari, H.; Waltzer, W.C.

    1982-01-01

    As part of a long-term intensive effort to apply the induction of adult allogensic unresponsiveness to the transplantation problem, two techniques to control the variability in the persistence of immunologically competent postthymic cells iin the treated host and/or the inoculum of autologous marrow returned to the host after irradiation are described. The first consisted of exposing the peripheral blood of prospective recipients to a 5-week course of extra-corporeal irradiation (ECIB), the other of exposing the stored autologous marrow scheduled to repopulate a given recipient to methyl-prednisolone (MPd) and DNase prior to renifusion into the recipient. Serial analysis of bone marrow cell samples at various intervals before and after treatment was undertaken. The significance of the disappearance of a particular population of nonnuclear cells from the samples, and the association of such disappearance with increased success in the induction of allogeneic unresponsiveness is discussed. (ACR)

  5. Sedimentological processes and environmental variability at Lake Ohrid (Macedonia, Albania) between 640 ka and present day

    NASA Astrophysics Data System (ADS)

    Francke, A.; Wagner, B.; Just, J.; Leicher, N.; Gromig, R.; Baumgarten, H.; Vogel, H.; Lacey, J. H.; Sadori, L.; Wonik, T.; Leng, M. J.; Zanchetta, G.; Sulpizio, R.; Giaccio, B.

    2015-09-01

    Lake Ohrid (FYROM, Albania) is thought to be more than 1.2 million years old and hosts more than 200 endemic species. As a target of the International Continental Scientific Drilling Program (ICDP), a successful deep drilling campaign was carried out within the scope of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) project in 2013. Here, we present lithological, sedimentological, and (bio-)geochemical data from the upper 247.8 m of the overall 569 m long DEEP site sediment succession from the central part of the lake. According to an age model, which is based on nine tephra layers (1st order tie points), and on tuning of biogeochemical proxy data to orbital parameters (2nd order tie points) and to the global benthic isotope stack LR04 (3rd order tie points), respectively, the analyzed sediment sequence covers the last 640 ka. The DEEP site sediment succession consists of hemipelagic sediments, which are interspersed by several tephra layers and infrequent, thin (< 5 cm) mass wasting deposits. The hemipelagic sediments can be classified into three different lithotypes. Lithotype 1 and 2 deposits comprise calcareous and slightly calcareous silty clay and are predominantly attributed to interglacial periods with high primary productivity in the lake during summer and reduced mixing during winter. The data suggest that high ion and nutrient concentrations in the lake water promoted calcite precipitation and diatom growth in the epilmnion in during MIS15, 13, and 5. Following a strong primary productivity, highest interglacial temperatures can be reported for MIS11 and 5, whereas MIS15, 13, 9, and 7 were comparable cooler. Lithotype 3 deposits consist of clastic, silty clayey material and predominantly represent glacial periods with low primary productivity during summer and longer and intensified mixing during winter. The data imply that most severe glacial conditions at Lake Ohrid persisted during MIS16, 12, 10, and 6 whereas somewhat warmer temperatures can be inferred for MIS14, 8, 4, and 3. Interglacial-like conditions occurred during parts of MIS14, and 8.

  6. Disposable sensor system: a present-day truly low cost unattended ground sensor system

    NASA Astrophysics Data System (ADS)

    Calcutt, Wade; Jones, Barry; McQuiddy, John

    2005-05-01

    This paper will review the work being performed at McQ on the development of a family of truly low cost unattended ground sensor systems using conventional technology and manufacturing techniques. The goal of this work is to produce tactically useable sensors that can be manufactured in large quantities (1-10M units/year) for $10 each. Secondary goals are small size (10-50 cm^3), lightweight (15-60gm), moderate lifetimes (48-72hrs) and moderate communications ranges (10-1000m). Our research indicates that sensors meeting these performance metrics can be manufactured today using conventional manufacturing techniques. The paper will review the basic system architecture proposed, projected sensor performance and projected manufacturing costs.

  7. Conventional extracapsular cataract extraction and its importance in the present day ophthalmic practice

    PubMed Central

    Mohanty, Preeti; Prasan, Vishnu Vahan; Vivekanand, U.

    2015-01-01

    Purpose: A retrospective study aimed to evaluate high risk cases where conventional Extracapsular cataract extraction (ECCE) was performed, their intra-operative and post-operative outcomes. Setting: Sri Srinivasa Sankara Nethralaya (Tirupati) Tirumala Tirupati Devastanams Central Hospital, Tirupati, India. Subjects and Methods: Retrospective study of 207 patients who underwent ECCE at the hospital between august 2010 to June 2012. Operative data included details like grade of risk, intra and postoperative complications and visual outcome. Results: Out of 207 cases, 188 were in group 3 (moderate risk, 3-5 points) and 19 in group 4 (high risk, 6 points or more). The intra operative complications in group 3 were 8 (0.042%) and none in group 4. Final best corrected visual acuity (BCVA) of 6/12 and more were 184 (88.88%). Final refraction of less than 2.0 astigmatism was seen in 80.19% (n=166). Conclusion: Segregation of cases depending on the risk factors can lead to lower intra operative complications and therefore good postoperative outcome. We believe that phacoemulsification, manual small incision cataract surgery (MSICS) and ECCE each has its own importance and should be used as per the cataract with risk factors. PMID:26903724

  8. Present-day plate motions: Retrieval from the TOPEX/Poseidon orbitography network (DORIS system)

    NASA Technical Reports Server (NTRS)

    Souriau, Annie; Cazenave, Anny; Biancale, R.; Balmino, G.; Dominh, K.; Mazzega, P.; Lemoine, J.-M.; Boucher, Claude; Willis, P.; Kasser, M.

    1991-01-01

    The goal of the proposal is to determine the present motion of the main tectonic plates from the Doppler data of the Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) orbitography system, which includes in its final configuration about 50 tracking stations with a world-wide distribution.

  9. Present-day stress directions in California determined through borehole breakout analysis

    SciTech Connect

    Mount, V.S.; Suppe, J.

    1988-03-01

    Borehole elongations or breakouts, observed on unprocessed four-arm dipmeter logs, have been used to map in-situ stress directions throughout onshore California. Approximately 130 wells were analyzed for borehole breakouts in California, with 107 giving useful results. The wells are subvertical (most inclinations > 80/sup 0/) and range in depth from 920 to 5760 m, with 90% of the wells being deeper than 1500 m. Breakouts were observed from depths of 100-5600 m. The number of broken out intervals per well range from 3 to 38 with an average of 12. A regionally consistent stress pattern is observed with maximum horizontal compression generally oriented northeast-southwest. Breakout-determined stress directions are consistent with other stress indicators, including stress directions determined from focal mechanisms for earthquakes occurring at depths of 5-15 km. The direction of maximum compression consistently intersects the San Andreas fault at a high angle (80/sup 0/-90/sup 0/) and is approximately perpendicular to axes of young thrust-related anticlines. Heat-flow and seismic observations limit the shear stress on the San Andreas fault to 10-20 MPa, or less. The observed orientation of maximum horizontal compression (nearly perpendicular) to the San Andreas) allows generation of large regional deviatoric stresses of rock-breaking magnitudes (on the order of 100 MPa). Transpressive plate motion is decoupled into a low-stress strike-slip component and a high-stress compressive component. These observations suggest that standard concepts of transpressive wrench tectonics - which envisage drag on a high-friction fault - are wrong. The thrust structures are largely decoupled from the strike-slip fault.

  10. Present-day crustal movements and the mechanics of cyclic deformation

    SciTech Connect

    Thatcher, W.

    1990-01-01

    Contemporary crustal movements in California are concentrated within a plate-boundary deformation zone that is typically 50 to 200 km wide, centered approximately on the San Andreas fault. Observations of coseismic, postseismic, and interseismic movements define the earthquake deformation cycle and constrain models of strain accumulation and release for strike-slip plate boundaries. This chapter describes shear strain on the San Andreas fault system; aseismic slip, integrated displacement rates, and Pacific-North American plate motion; detailed displacement-rate patterns; and thick- and thin-lithosphere models and stress-slip-constitutive-law fault models of deformation.

  11. Thus Spoke Galileo - The great scientist's ideas and their relevance to the present day

    NASA Astrophysics Data System (ADS)

    Frova, Andrea; Marenzana, Mariapiera

    2006-04-01

    Any reasonably educated person knows what is said about Galileo, but not what Galileo himself actually said. This has allowed a variety of different interpretations to be put upon his stands as a scientist and as a man, in particular from within the Catholic world, where a sense of guilt for his dramatic destiny has never been completely erased. Let him speak, then so that he can bring to everybody's attention, in particular the young, his message of reason, of intellectual honesty, of free thinking. A message that more than ever, is of great relevance in the rampant irrationality of the new millennium. The selection of writings offered here is preferred by a blunt self-portrait, which is of course a "forgery" - however, one that is based entirely on extracts from Galileo's writings and private letters, though he would never have dared, nor been allowed to write it himself. The anthology touches upon the themes dearest to Galileo and a lively commentary, from both the scientific and the literary-historical viewpoints, should help make the extracts accessible. The reader will be able to appreciate the work and the writing-style of a very great scientist and author and will probably also be surprised to find with the aid of a test with answers provided, just how many of the misconceptions about the "workings of the world" that were rife prior to Galileo, still survive today among the common beliefs of even well-educated, non scientific people.

  12. [The demographic dynamics of the neighborhoods of Lubumbashi from its foundation to the present day].

    PubMed

    Bruneau, J; Lootens-de Muynck, M

    1985-01-01

    The authors examine the spatial growth of the city of Lubumbashi, Zaire, since its foundation some 75 years ago. Current trends in urban spatial distribution are analyzed using data from a survey and aerial photography. The contrast in population density between the more prosperous neighborhoods and the poorer districts is noted. (SUMMARY IN ENG) PMID:12269192

  13. Present Day Biology seen in the Looking Glass of Physics of Complexity

    NASA Astrophysics Data System (ADS)

    Schuster, P.

    Darwin's theory of variation and selection in its simplest form is directly applicable to RNA evolution in vitro as well as to virus evolution, and it allows for quantitative predictions. Understanding evolution at the molecular level is ultimately related to the central paradigm of structural biology: sequence⇒ structure ⇒ function. We elaborate on the state of the art in modeling and understanding evolution of RNA driven by reproduction and mutation. The focus will be laid on the landscape concept—originally introduced by Sewall Wright—and its application to problems in biology. The relation between genotypes and phenotypes is the result of two consecutive mappings from a space of genotypes called sequence space onto a space of phenotypes or structures, and fitness is the result of a mapping from phenotype space into non-negative real numbers. Realistic landscapes as derived from folding of RNA sequences into structures are characterized by two properties: (i) they are rugged in the sense that sequences lying nearby in sequence space may have very different fitness values and (ii) they are characterized by an appreciable degree of neutrality implying that a certain fraction of genotypes and/or phenotypes cannot be distinguished in the selection process. Evolutionary dynamics on realistic landscapes will be studied as a function of the mutation rate, and the role of neutrality in the selection process will be discussed.

  14. MCTP Summer Research Internship Program. Research Presentation Day: Experience Mathematics and Science in the Real World

    NASA Technical Reports Server (NTRS)

    1996-01-01

    This paper presents the summaries of the MCTP Summer Research Internship Program. Technological areas discussed include: Mathematical curriculum development for real world problems; Rain effects on air-water gas exchange; multi-ring impact basins on mars; developing an interactive multimedia educational cd-rom on remote sensing; a pilot of an activity for for the globe program; fossils in maryland; developing children's programming for the american horticultural society at river farm; children's learning, educational programs of the national park service; a study of climate and student satisfaction in two summer programs for disadvantaged students interested in careers in mathematics and science; the maryland governor's academy, integrating technology into the classroom; stream sampling with the maryland biological stream survey (MBSS); the imaging system inspection software technology, the preparation and detection of nominal and faulted steel ingots; event-based science, the development of real-world science units; correlation between anxiety and past experiences; environmental education through summer nature camp; enhancing learning opportunities at the Salisbury zoo; plant growth experiment, a module for the middle school classroom; the effects of proxisome proliferators in Japanese medaka embryos; development of a chapter on birth control and contraceptive methodologies as part of an interactive computer-based education module on hiv and aids; excretion of gentamicin in toadfish and goldfish; the renaissance summer program; and Are field trips important to the regional math science center?

  15. Present-day formation and seasonal evolution of linear dune gullies on Mars

    NASA Astrophysics Data System (ADS)

    Pasquon, Kelly; Gargani, Julien; Massé, Marion; Conway, Susan

    2016-04-01

    Linear dune gullies are an enigmatic sub-type of martian gullies. As their name suggests they only occur on sandy substrates and comprise very long (compared to their width) straight or sinuous channels, with relatively small source areas and almost inexistent deposits. This specific morphology has never been observed on terrestrial dunes and its formation process on Mars is still unclear [e.g. 1, 2, 3]. Here, we present the results of the first systematic survey for these features in Mars' southern hemisphere and an in-depth study of six dune fields where repeat-imaging allows us to monitor the changes over time of these linear gullies. This study was performed with HiRISE images at 25-30 cm/pix and 1 m/pix elevation data derived from HiRISE stereo images. We find the latitudinal distribution and orientation of linear gullies is broadly consistent with the general population of martian gullies. They occur predominantly between 36.3°S and 54.3°S, and occasionally between 64.6°S and 70.4°S. They are oriented towards SSW (between 150°N and 260°N). In contrast with the general gully population, however, we find that these gullies are extremely active over the 5 Mars years of images. Activity comprises: (i) appearance of new channels, (ii) elongation of existing channels, (iii) complete or partial reactivation, and (iv) disappearance of gullies. Gully channels can elongate by an average ~100 m per year. Their intense activity and the progressive disappearance of linear gullies argues against the hypothesis that these are remnant morphologies left over from previous periods of high obliquity millions of years ago. The activity of linear dune gullies reoccurs every year between the end of winter and the beginning of spring (Ls 167.4° - 216.6°), coinciding with the final stages of the sublimation of annual CO₂ frosts. This activity often coincides spatially and temporally with the appearance of Recurrent Diffusing Flows (RDF) - dark patches which surround the active site. South and SSW-facing dune slopes are those which preferentially host CO2 frost deposits, however, only those dune slopes with angles ~13° possess linear dune gullies, suggesting a slope-limited formation process. These observations provide a wealth of temporal and morphometric constraints that can be used to perform numerical modelling, to direct future image monitoring and guiding laboratory experiments which can be used to better constrain the formation process of these enigmatic features. [1] Mangold et al., 2003. J. Geophys. Res., 108 (E4), 5027. [2] Reiss et al., 2010. Geophys. Res. Lett. 37, L06203. [3] Diniega et al., 2013. Icarus 225, 526-537.

  16. Present-day formation and seasonal evolution of linear dune gullies on Mars

    NASA Astrophysics Data System (ADS)

    Pasquon, Kelly; Gargani, Julien; Massé, Marion; Conway, Susan J.

    2016-08-01

    Linear dune gullies are a sub-type of martian gullies. As their name suggests they only occur on sandy substrates and comprise very long (compared to their width) straight or sinuous channels, with relatively small source areas and almost non-existent visible deposits. Linear dune gullies have never been observed on terrestrial dunes and their formation process on Mars is unclear. Here, we present the results of the first systematic survey of these features in Mars' southern hemisphere and an in-depth study of six dunefields where repeat-imaging allows us to monitor the changes in these gullies over time. This study was undertaken with HiRISE images at 25-30 cm/pix and 1 m/pix elevation data derived from HiRISE stereo images. We find the latitudinal distribution and orientation of linear dune gullies broadly consistent with the general population of martian gullies. They occur predominantly between 36.3°S and 54.3°S, and occasionally between 64.6°S and 70.4°S. They are generally oriented toward SSW (at bearings between 150° and 260°). We find that these gullies are extremely active over the most recent 5 Martian years of images. Activity comprises: (1) appearance of new channels, (2) lengthening of existing channels, (3) complete or partial reactivation, and (4) disappearance of gullies. We find that gully channels lengthen by ∼100 m per year. The intense activity and the progressive disappearance of linear dune gullies argues against the hypothesis that these are remnant morphologies left over from previous periods of high obliquity millions of years ago. The activity of linear dune gullies reoccurs every year between the end of winter and the beginning of spring (Ls 167.4°-216.6°), and coincides with the final stages of the sublimation of annual CO₂ ice deposit. This activity often coincides spatially and temporally with the appearance of recurrent diffusing flows (RDFs)-digitate-shaped, dark patches with low relative albedo (up to 48% lower than the adjacent dune) that encompass the active site. South- and SSW-facing dune slopes are those which preferentially host CO2 frost deposits, however, it is only those with angles of ∼20° just below the crest which possess linear dune gullies, suggesting a slope-limited formation process. These observations provide a wealth of temporal and morphometric data that can be used to undertake numerical modeling, to direct future image monitoring and guide laboratory experiments that can be used to better constrain the formation process of these features.

  17. A summary of present-day gully formation and activity on Mars

    NASA Astrophysics Data System (ADS)

    Diniega, Serina; Hansen, Candice; McEwen, Alfred; Dundas, Colin; Byrne, Shane

    2016-07-01

    Over the past decade, gully activity has been carefully monitored on a range of slopes, including dune slopes [1-3] and crater walls [2-4]. Within the southern mid-latitudes, substantial changes in gully morphology have been observed. On dune slopes, observed activity includes major incision (forming a new channel or expanding an existing channel), changes in channel sinuosity, expansion of alcoves, and deposition of an extensive new apron. On rockier slopes, observed activity has cut new channel segments and small terraces, abandoned other channels, and deposited boulder-rich lobate features. Many of these morphologies have been treated as indicative of fluvial processes. However, long-term monitoring campaigns with High Resolution Imaging Science Experiment (HiRISE) data [2-5] of almost 500 gully locations, have shown that the timing of this current activity is generally correlated with the presence of seasonal frost [1-5]. Moreover, the distribution of seasonal frost on slopes is similar to the orientation distribution of gullies [3,6]. Most seasonal frost is CO2, and this is likely the main cause of current activity. Recent modeling has shown that CO2 sublimation from within the regolith pores would be sufficient to create the types of geomorphology seen within martian gullies [7]. Water frost may be involved in some small-scale activity [5]. Liquid water is unlikely to be relevant, because the abundance of water frost is generally low [8] and melting is difficult. An additional current focus is on the north polar sand sea, where "gullies" (generally lacking a channel) have been observed to form on dune slopes over seasonal and annual timescales. There, we aim to differentiate between either a general aeolian [8] or seasonal frost driver [9,10] for the formation process. For these features, formation timing estimates are often less constrained because HiRISE images are not acquired during fall and winter, due to the polar hood and darkness. Thus, analysis of trends and variations in gully size, morphology, orientation, and location are additionally examined as indications of a seasonal (or other) control, as well as variations with latitude, dune type/size/orientation, or Mars year. This presentation will summarize the results of our monitoring campaigns, and will compare the data that are available about gullies of different morphologies and locations. Our aim is to identify possible similarities (and differences) in gully activity processes across Mars, and to estimate the rates of gully formation and modification processes (as has been done for gullies in the southern mid-latitudes [3]). Such estimates would aid interpretation of the likely ages of observed gullies, which have implications for whether records of past (and potential aqueous) gully formation processes are still observable. [1] Diniega et al. (2010) Geology, 38, 1047-1050. [2] Dundas et al. (2012) Icarus, 220, 124-143. [3] Dundas et al. (2015) Icarus, 251, 244-263. [4] Dundas et al. (2010) GRL, 37, L07202. [5] Vincendon (2015) JGR, 120, 1859-1879. [6] Harrison et al. (2015) Icarus, 252, 236-254. [7] Pilorget & Forget (2016) Nature Geosci. 9, 65-69. [8] Vincendon et al. (2010) JGR, 115, E10001. [9] Horgan & Bell (2012) Geophys. Res. Lett. 39, L09201. [10] Hansen et al., (2011) Science 331, 575-578. [11] Hansen et al. (2015) Icarus 251, 264-267.

  18. Present-day radio-astronomical systems of aperture synthesis (Review)

    NASA Astrophysics Data System (ADS)

    Tseitlin, N. M.

    The characteristics of a number of synthetic-aperture radio telescopes are presented. Particular consideration is given to cruciform and T-shaped radio telescopes consisting of 'linear' antennas (Mills crosses); multielement radio telescopes with immobile antennas; multielement radio telescopes with immobile and moving elements; and millimeter-wave interferometers.

  19. An approach to modeling present-day deformation in southern California

    NASA Technical Reports Server (NTRS)

    Rundle, J. B.

    1986-01-01

    This paper presents an approach to modeling the complete, time-dependent deformation in southern California. A variety of techniques are used to include the far-field plate motion, stress relaxation in the asthenosphere, aseismic fault slip within the elastic lithosphere, and the complex, three-dimensional nature of the faults within the southern California region. Among the conclusions of the work here are the following: (1) the data exibit a marginal preference for a relatively thin lithosphere in southern California: (2) the most sensitive determinant for lithospheric thickness and viscosity of the asthenosphere is the rotation rate of the motion vectors toward or away from major faults; (3) the major faults in southern California are slipping at depth, at or near their average Holocene rates; (4) a shallow, active decollement beneath the Transverse Ranges is apparently needed to realistically model the strain changes observed there; and (5) this modeling technique offers the best approach for understanding the complex deformation field in southern California.

  20. Present-Day Influence of English on Swedish as Found in Swedish Job Advertisements.

    ERIC Educational Resources Information Center

    Larson, Ben E.

    1990-01-01

    A brief analysis of job advertisements in Swedish newspapers notes the increasing trend toward the use of English rather than Swedish words for certain terms, attributing such use to the wish to show an international labor perspective. (five references) (CB)

  1. An approach to modeling present-day deformation in southern California

    SciTech Connect

    Rundle, J.B.

    1986-02-10

    This paper presents an approach to modeling the complete, time-dependent deformation in southern California. We make use of a variety of techniques to include the far-field plate motion, stress relaxation in the asthenosphere, aseismic fault slip within the elastic lithosphere, and the complex, three-dimensional nature of the faults within the southern California region. Among the conclusions of the work here are the following: (1) the data exhibit a marginal preference for a relatively thin lithosphere in southern California, (2) the most sensitive determinant for lithospheric thickness and viscosity of the asthenosphere is the rotation rate of the motion vectors toward or away from major faults, (3) major faults in southern California are slipping at depth, at or near their average Holocene rates, (4) a shallow, active decollement beneath the Transverse Ranges is apparently needed to realistically model the strain changes observed there, and (5) this modeling technique offers the best approach for understanding the complex deformation field in southern California.

  2. A Present-day Educational View of the Thought of Democritus.

    ERIC Educational Resources Information Center

    Cosmopoulos, Alexander

    1980-01-01

    The Democritean pedagogic credo says that: (1) man can be changed and shaped through education; (2) education should function in correspondence with the theoretical and practical needs of man; (3) education has a strong ethical and ascetic character; and (4) difficulty must be accepted as a unique means of education. (RM)

  3. Geochemistry and geobiology of a present-day serpentinization site in California: The Cedars

    NASA Astrophysics Data System (ADS)

    Morrill, Penny L.; Kuenen, J. Gijs; Johnson, Orion J.; Suzuki, Shino; Rietze, Amanda; Sessions, Alex L.; Fogel, Marilyn L.; Nealson, Kenneth H.

    2013-05-01

    Ultra-basic (pH 11-12) reducing (-656 to -585 mV) groundwater springs discharging from serpentinized peridotite of The Cedars, CA, were investigated for their geochemistry and geobiology. The spring waters investigated were of meteoric origin; however, geochemical modeling suggests that there were two sources of groundwater, a shallow source with sufficient contact with The Cedars' peridotite body to be altered geochemically by serpentinization, and a deeper groundwater source that not only flows through the peridotite body but was also in contact with the marine sediments of the Franciscan Subduction Complex (FSC) below the peridotite body. We propose that the groundwater discharging from lower elevations (GPS1 and CS1) reflect the geochemistry of the deeper groundwater in contact with FSC, while groundwaters discharging from springs at higher elevations (NS1 and BSC) were a mixture of the shallow peridotite-only groundwater and the deeper groundwater that has been in contact with the FSC. Cell densities of suspended microbes within these waters were extremely low. In the NS1 and BSC spring fluids, cell densities ranged from 102 to 103 cells/ml, while suspended cells at GPS were lower than 10 cells/mL. However, glass slides incubated in the BSC and GPS1 springs for 2-3 weeks were colonized by cells with densities ranging from 106 to 107 cells/cm2 attached to their surfaces. All of the springs were very low (⩽1 μM) in several essential elements and electron acceptors (e.g. nitrate/ammonium, sulfate, and phosphate) required for (microbial) growth, which is not uncommon at sites of continental serpentinization. Gases rich in N2, H2, and CH4 were exsolving from the springs. The stable carbon isotope value (δ13CCH4 = -68 ± 0.6‰) and the CH4/C2+ (>103) of methane and other gaseous hydrocarbons exsolving from NS1 were typical of microbially sourced methane, whereas the isotope values and the CH4/C2+ of BSC and CS1 springs were more enriched in 13C and had CH4/C2+ < 103, suggesting a mixture of microbial and non-microbial methane. The concentrations of aromatic compounds, and ethane, propane, iso- and n-butane were well described by simple physical mixing between the aromatic- and alkane-poor, shallow groundwater and the relatively aromatic, and alkane-rich groundwater that flows through both the peridotite and the FSC suggesting that these aromatic and alkane compounds originated in the deeper FSC groundwater and are not produced in the shallow peridotite-only groundwater. The aromatic compounds most probably originated from the diagenesis/degradation of organic matter in the marine sediments below the peridotite body, while the gaseous alkanes may have multiple sources including thermal degradation of the organic matter in the marine sediments below the peridotite body and possibly by abiogenic reactions occurring within the peridotite body. This geochemical study demonstrates the complexity of The Cedars, and the possible sources of hydrocarbons at continental sites of serpentinization.

  4. Multiple prismatic calcium phosphate layers in the jaws of present-day sharks (Chondrichthyes; Selachii).

    PubMed

    Dingerkus, G; Séret, B; Guilbert, E

    1991-01-15

    Jaws of large individuals, over 2 m in total length, of the shark species Carcharodon carcharias (great white shark) and Isurus oxyrinchus (mako shark) of the family Lamnidae, and Galeocerdo cuvieri (tiger shark) and Carcharhinus leucas (bull shark) of the family Carcharhinidae were found to have multiple, up to five, layers of prismatic calcium phosphate surrounding the cartilages. Smaller individuals of these species and other known species of living chondrichthyans have only one layer of prismatic calcium phosphate surrounding the cartilages, as also do most species of fossil chondrichthyans. Two exceptions are the fossil shark genera Xenacanthus and Tamiobatis. Where it is found in living forms, this multiple layered calcification does not appear to be phylogenetic, as it appears to be lacking in other lamnid and carcharhinid genera and species. Rather it appears to be functional, only appearing in larger individuals and species of these two groups, and hence may be necessary to strengthen the jaw cartilages of such individuals for biting. PMID:1999241

  5. Present-day shortening in Southern Haiti from GPS measurements and implications for seismic hazard

    NASA Astrophysics Data System (ADS)

    Symithe, Steeve; Calais, Eric

    2016-06-01

    The ~ 3 M inhabitant capital region of Haiti, severely affected by the devastating January 12, 2010, M7.0 earthquake, continues to expand at a fast rate. Accurate characterization of regional earthquake sources is key to inform urban development and construction practices through improved regional seismic hazard estimates. Here we use a recently updated Global Positioning System (GPS) data set to show that seismogenic strain accumulation in southern Haiti involves an overlooked component of shortening on a south-dipping reverse fault along the southern edge of the Cul-de-Sac basin, in addition to the well-known component of left-lateral strike-slip motion. This tectonic model implies that ground shaking may be twice that expected if the major fault was purely strike-slip, as assumed in the current seismic hazard map for the region.

  6. Present-day biogeochemical activities of anaerobic bacteria and their relevance to future exobiological investigations

    USGS Publications Warehouse

    Oremland, R.S.

    1989-01-01

    If the primordial atmosphere was reducing, then the first microbial ecosystem was probably composed of anaerobic bacteria. However, despite the presence of an oxygen-rich atmosphere, anaerobic habitats are important, commonplace components of the Earth's present biosphere. The geochemical activities displayed by these anaerobes impact the global cycling of certain elements (e.g., C, N, S, Fe, Mn, etc.). Methane provides an obvious example of how human-enhanced activities on a global scale can influence the content of a "radiative" (i.e., infrared absorbing) trace gas in the atmosphere. Methane can be oxidized by anaerobic bacteria, but this does not appear to support their growth. Acetylene, however, does support such growth. This may form the basis for future exobiological investigations of the atmospheres of anoxic, hydrocarbon-rich planets like Jupiter and Saturn, as well as the latter's satellite Titan. ?? 1989.

  7. Present-day CGPS-derived Crustal Strain Rate Field of the Saint Lawrence River Valley

    NASA Astrophysics Data System (ADS)

    Goudarzi, M. A.; Cocard, M.; Santerre, R.

    2015-12-01

    The Saint Lawrence River valley (SLRV) is one of the most seismically active areas in eastern Canada. Along the SLRV and the Ottawa valley, earthquakes are concentrated on three distinct zones of western Quebec along the Ottawa River, Charlevoix, and Lower Saint Lawrence. The entire area is also subject to the glacial isostatic adjustment (GIA). We studied the earth's surface deformation of the area using the velocity field of 51 continuous GPS (CGPS) stations and the least-squares collocation method. While the intraplate horizontal velocities showed a coherent horizontal motion towards southeast with the typical magnitude of ~1.3 mm/yr for stations along the SLRV, the interpolated vertical velocities demonstrated a coherent uplift with the average rate of 3.1 mm/yr. We estimated strain rate tensors including the effect of vertical velocity. A NNW-SSE shortening with a typical rate of ~3.6-8.1 nstrain/yr was observed over Lower Saint Lawrence. In Charlevoix, an extension with a typical rate of ~3.0-7.1 nstrain/yr was oriented in ENE-WSW parallel to the SLRV. In western Quebec, the deformation has a shear straining mechanism with a typical shortening rate of ~1.0-5.1 nstrain/yr and extension rate of ~1.6-4.1 nstrain/yr. The extension over the northern model is consistent with the prediction of the GIA models. The range of the estimated strain rates of the area (~1.0-8.1 nstrain/yr) is between typical values of rigid blocks (< 0.1 nstrain/yr) and active tectonic regions (> 100 μstrain/yr). A strong correlation was observed between epicenters of earthquakes and areas with the highest rate of shear strain. We found a good agreement between the orientations of the principal axes of strain rate tensors and the maximum horizontal compressional stress σH from World Stress Map 2008 for both strike-slip and thrust faulting regimes especially those derived from focal mechanisms. This shows our CGPS intraplate velocities are representative of the current crustal deformation associated with the GIA and that they constrain the crustal strain rates in magnitude, direction and origin.

  8. Present-day groundwater recharge estimation in parts of the Indian Sub-Continent

    NASA Astrophysics Data System (ADS)

    Bhanja, S. N.; Mukherjee, A.; Wada, Y.; Scanlon, B. R.; Taylor, R. G.; Rodell, M.; Malakar, P.

    2015-12-01

    Large part of global population has been dependent on groundwater as a source of fresh water. The demand would further increase with increasing population and stress associated with climate change. We tried to provide regional-scale groundwater recharge estimates in a large part of Indian Sub-Continent. A combination of ground-based, satellite-based and numerical model simulated recharge estimates were presented in the densely populated region. Three different methods: an intense network of observational wells (n>13,000 wells), a satellite (TRMM) and global land-surface model (CLM) outputs, and a global-scale hydrological model (PCR GLOBWB) were employed to calculate recharge estimates. Groundwater recharge values exhibit large spatial variations over the entire region on the basis of aquifer hydrogeology, precipitation and groundwater withdrawal patterns. Groundwater recharge estimates from all three estimation techniques were found to be higher (>300 mm/year) in fertile planes of Indus-Ganges-Brahmaputra (IGB) river basins. A combination of favorable hydrogeologic conditions (porosity, permeability etc.), comparatively higher rates of precipitation, and return flow from rapidly withdrawn irrigation water might influence occurrence of high recharge rates. However, central and southern study area experiences lower recharge rates (<200 mm/year), might be associated with unfavorable hydrogeologic conditions associated with cratonic provinces. Statistical analysis of inter-comparison between the three different recharge estimates show good matches in some of the areas. Recharge estimates indicate dynamic nature of groundwater recharge as a function of precipitation, land use pattern, and hydrogeologic parameters. On a first hand basis, the estimates will help policy makers to understand groundwater recharge process over the densely populated region and finally would facilitate to implement sustainable policy for securing water security.

  9. Modeling Greenland ice sheet present-day and near-future runoff contribution.

    NASA Astrophysics Data System (ADS)

    Peano, Daniele; Colleoni, Florence; Masina, Simona

    2014-05-01

    The last IPCC report [AR5, IPCC] has shown an increasing contribution from Greenland melting to global sea-level over the last decade, increasing from 0.09 mm/year (period 1992-2001) to 0.59 mm/year (period 2002-2011). Given its strategic location, i.e. close to the main North Atlantic ocean convection sites, it is therefore of importance to better assess ice sheet melting and its impact on regional ocean processes. So far, runoff estimate from ice sheet has been poorly constrained (e.g. [Hanna et al., 2005], [Hanna et al., 2008]) and most of the time the few estimates comes from regional atmospheric models or general circulation models (e.g. [Edwards et al., 2013], [Fettweis et al., 2013]). Here, we present the results from the implementation of a routing scheme into the thermo-mechanical ice sheet-ice shelves model GRISLI [Ritz et al, 2001], applied to the Greenland ice sheet mass evolution over the 20th and 21st centuries. The routing scheme is based on the "multiple flow direction" developed by [Quinn et al., 1991]. We further improved this scheme by considering topographic depressions as possible "lakes" to be filled by meltwater. In this way, when a depression is filled, only the extra water is routed towards the Greenland coasts. This allow us to obtain an estimate of the total amount of freshwater reaching the ocean at each time step of the model integration, as well as a time-varying spatial distribution of the runoff along the coasts of Greenland. This routing scheme is applied in routing both surface and basal meltwater. Surface meltwater is computed by means of a PDD method [Fausto et al., 2007] on which only a fraction is considered for routing while the basal melting rate is part of the heat balance at the ice-bed interface. Runoff is simulated on a 5km x 5km horizontal grid and validation is performed over the 20th century using mean annual total precipitation and air temperature at 2 meters from Era-Interim reanalysis [Dee et al., 2011]. Near future projections are then computed using the climate forcing from CMCC 21st century CMIP5 simulations (RCP 8.5 and RCP 4.5). Since the results could be dependent on the ice dynamics and on the surface mass balance method, the runoff scheme is also implemented in the land-based model SICOPOLIS [Greve, 1995] and results are compared to those obtained with GRISLI.

  10. Kuiper's Double Planet: Mantle Convection In The Present-day Earth

    NASA Astrophysics Data System (ADS)

    Bostrom, R. C.

    To what extent does the gravity field of the Moon, rotating relative to the geocentric field of the Earth [1], affect convection in the mantle? This enquiry follows a formula- tion developed by Chandrasekhar, evaluating convection in a body subject additionally to an external field. The tides have been examined as measure of the Earth-Moon interaction. Dissipation estimates based respectively on an oceanic data set of unprecedented precision [2] and a continental gravimetric set [3] are compatible when observations are referred to the M2 wave, in contrast to a fictitious geostationary bulge. The external contribution required to produce asymmetry in convection internally powered is theoretically infinitesimal, but in practice unknown. Reduced in cog- nizance of the M2 wave, the tidal data indicate that dissipation in the mantle represents a fraction of up to 50 Under Earth's supercritical Rayleigh number, not less than 10(6), internally powered mantle convection must exist but necessarily is a function of the TOTAL field. It seems possible that basically the 'two-body' Rayleigh number determines the phase- lag, hence also the despin rate, in respect to the tidal Earth. The model best-fitting current observations expects a flow bias, sharply peaked in low latitudes. Its sense is to foster the development of the west limb of convection structures. The theoretical surface displacement resembles a continuation of the Cenozoic plate motion found by Gordon and Jurdy (1986). With a view to understanding unexplained aspects of 'plate tectonics', it would be valuable to test the currently best-fitting 2-body model using GPS to overcome the 'absolute-motion' difficulty, by observing latitude-dependence (or otherwise) of rela- tive motion between cratonic stations. [1] RCB 2000: Tectonic Consequences of Earth's Rotation. Oxford UP: sect. 4.3. [2] Ray,R.D. et al. 2001. Geophys. J.Intern. 144: 471-480. [3] Melchior, Bn. P., 1994. Phys. Ea. Plan. Ints. 82: 125-156.

  11. The contribution of natural selection to present-day susceptibility to chronic inflammatory and autoimmune disease

    PubMed Central

    Brinkworth, Jessica F; Barreiro, Luis B

    2015-01-01

    Chronic inflammatory and autoimmune diseases have been the focus of many genome-wide association studies (GWAS) because they represent a significant cause of illness and morbidity, and many are heritable. Almost a decade of GWAS studies suggests that the pathological inflammation associated with these diseases is controlled by a limited number of networked immune system genes. Chronic inflammatory and autoimmune diseases are enigmatic from an evolutionary perspective because they exert a negative affect on reproductive fitness. The persistence of these conditions may be partially explained by the important roles the implicated immune genes play in pathogen defense and other functions thought to be under strong natural selection in humans. The evolutionary reasons for chronic inflammatory and autoimmune disease persistence and uneven distribution across populations are the focus of this review. PMID:25458997

  12. Ancient human genomes suggest three ancestral populations for present-day Europeans

    PubMed Central

    Lazaridis, Iosif; Patterson, Nick; Mittnik, Alissa; Renaud, Gabriel; Mallick, Swapan; Kirsanow, Karola; Sudmant, Peter H.; Schraiber, Joshua G.; Castellano, Sergi; Lipson, Mark; Berger, Bonnie; Economou, Christos; Bollongino, Ruth; Fu, Qiaomei; Bos, Kirsten I.; Nordenfelt, Susanne; Li, Heng; de Filippo, Cesare; Prüfer, Kay; Sawyer, Susanna; Posth, Cosimo; Haak, Wolfgang; Hallgren, Fredrik; Fornander, Elin; Rohland, Nadin; Delsate, Dominique; Francken, Michael; Guinet, Jean-Michel; Wahl, Joachim; Ayodo, George; Babiker, Hamza A.; Bailliet, Graciela; Balanovska, Elena; Balanovsky, Oleg; Barrantes, Ramiro; Bedoya, Gabriel; Ben-Ami, Haim; Bene, Judit; Berrada, Fouad; Bravi, Claudio M.; Brisighelli, Francesca; Busby, George B. J.; Cali, Francesco; Churnosov, Mikhail; Cole, David E. C.; Corach, Daniel; Damba, Larissa; van Driem, George; Dryomov, Stanislav; Dugoujon, Jean-Michel; Fedorova, Sardana A.; Romero, Irene Gallego; Gubina, Marina; Hammer, Michael; Henn, Brenna M.; Hervig, Tor; Hodoglugil, Ugur; Jha, Aashish R.; Karachanak-Yankova, Sena; Khusainova, Rita; Khusnutdinova, Elza; Kittles, Rick; Kivisild, Toomas; Klitz, William; Kučinskas, Vaidutis; Kushniarevich, Alena; Laredj, Leila; Litvinov, Sergey; Loukidis, Theologos; Mahley, Robert W.; Melegh, Béla; Metspalu, Ene; Molina, Julio; Mountain, Joanna; Näkkäläjärvi, Klemetti; Nesheva, Desislava; Nyambo, Thomas; Osipova, Ludmila; Parik, Jüri; Platonov, Fedor; Posukh, Olga; Romano, Valentino; Rothhammer, Francisco; Rudan, Igor; Ruizbakiev, Ruslan; Sahakyan, Hovhannes; Sajantila, Antti; Salas, Antonio; Starikovskaya, Elena B.; Tarekegn, Ayele; Toncheva, Draga; Turdikulova, Shahlo; Uktveryte, Ingrida; Utevska, Olga; Vasquez, René; Villena, Mercedes; Voevoda, Mikhail; Winkler, Cheryl; Yepiskoposyan, Levon; Zalloua, Pierre; Zemunik, Tatijana; Cooper, Alan; Capelli, Cristian; Thomas, Mark G.; Ruiz-Linares, Andres; Tishkoff, Sarah A.; Singh, Lalji; Thangaraj, Kumarasamy; Villems, Richard; Comas, David; Sukernik, Rem; Metspalu, Mait; Meyer, Matthias; Eichler, Evan E.; Burger, Joachim; Slatkin, Montgomery; Pääbo, Svante; Kelso, Janet; Reich, David; Krause, Johannes

    2014-01-01

    We sequenced the genomes of a ~7,000 year old farmer from Germany and eight ~8,000 year old hunter-gatherers from Luxembourg and Sweden. We analyzed these and other ancient genomes1–4 with 2,345 contemporary humans to show that most present Europeans derive from at least three highly differentiated populations: West European Hunter-Gatherers (WHG), who contributed ancestry to all Europeans but not to Near Easterners; Ancient North Eurasians (ANE) related to Upper Paleolithic Siberians3, who contributed to both Europeans and Near Easterners; and Early European Farmers (EEF), who were mainly of Near Eastern origin but also harbored WHG-related ancestry. We model these populations’ deep relationships and show that EEF had ~44% ancestry from a “Basal Eurasian” population that split prior to the diversification of other non-African lineages. PMID:25230663

  13. Present-day fluxes of coccolithophores and diatoms in the pelagic Ionian Sea

    NASA Astrophysics Data System (ADS)

    Malinverno, Elisa; Maffioli, Paola; Corselli, Cesare; De Lange, Gert J.

    2014-04-01

    Biogenic fluxes from two sediment traps in the Ionian sea (35°13‧N, 21°30‧E) at 500 and 2800 m water depth are discussed in relation with the main oceanographic and external forcing and compared with previous data from a nearby location. This study is part of a multi-year sediment trap deployment, aimed at assessing seasonality and interannual variability of biogenic and abiogenic fluxes. Here, we focus on fluxes related to two main phytoplankton groups: coccolithophores and diatoms. At our mooring site, high-coccolithophore and low-diatom fluxes confirm the oligotrophic character of the pelagic eastern Mediterranean year-round. Coccolithophore assemblages are dominated by the cosmopolitan species Emiliania huxleyi, followed by the deep-dwelling Florisphaera profunda and by several minor species. Diatom assemblages are dominated by Thalassionema bacillare and Nitzschia interruptestriata, with ~ 100 common and minor species. Overall, the combined flux pattern of coccolithophores and diatoms shows a clear seasonality throughout the study period, which can be related to changing oceanographic conditions and a different depth of production within the photic zone. Worth to note is the extremely high abundance, with respect to previous pelagic records, of species indicative of an intense deep chlorophyll maximum (DCM), which could indicate a shoaling of the nutricline. This feature can be related to the variability that affects surface hydrography and the deep water masses. Additionally, the occurrence of neritic, benthic and brackish to fresh-water diatom species, mainly in the deeper trap, could be linked to either lateral transport within the water column or the atmospheric input of Saharan dust, which is known to be common over the eastern Mediterranean especially during spring time. Finally, correlation of the flux pattern at different depths allowed sinking speeds for total and biogenic particles to be calculated, which ranged from 70 to > 200 m day- 1. Three possible mechanisms can explain such high sinking rates and the coincidence of biogenic and total particle fluxes in the traps: a) the ballast effect of coccoliths; b) the packaging effect of fecal pellets related to the grazing activity of zooplankton; and c) the ballast effect of dust particles.

  14. The Cosmic Stories: Beginning, Evolution, and Present Days of the Universe

    NASA Astrophysics Data System (ADS)

    Tseliakhovich, Dmitriy

    The first part of this work is focused on the epoch of inflation. In this work we study the effect of primordial non-Gaussianity on the cosmic microwave background (CMB) and on large-scale structure in a two-field inflationary model in which both the inflaton and curvaton fields contribute to the primordial density fluctuations. We show that in addition to the previously described enhancement of the galaxy bias on large scales, this setup results in large-scale stochasticity. We provide joint constraints on the local non-Gaussianity parameter f˜NL and the ratio xi of the amplitude of primordial perturbations due to the inflaton and curvaton using WMAP and Sloan Digital Sky Survey (SDSS) data. The second and largest part of this study is focused on the formation of the first cosmic structures and the effect of relative velocity between dark matter and baryonic fluids. In that part we discuss a very important and previously unnoticed effect which significantly changes the process of structure formation in the early universe. At the time of recombination, baryons and photons decoupled and the sound speed in the baryonic fluid dropped from relativistic, ˜ c/ 3 , to the thermal velocity of the hydrogen atoms ˜ 2 x 10 -5c. This is less than the relative velocity of baryons and dark matter computed via linear perturbation theory, so we infer that there are supersonic coherent flows of the baryons relative to the underlying potential wells created by the dark matter. As a result, the advection of small-scale perturbations (near the baryonic Jeans scale) by large-scale velocity flows is important for the formation of the first structures. This effect involves a quadratic term in the cosmological perturbation theory equations and hence has not been included in studies based on linear perturbation theory. We show that the relative motion suppresses the abundance of the first bound objects, even if one only investigates dark matter halos, and leads to qualitative changes in their spatial distribution, such as introducing scale-dependent bias and stochasticity. We further discuss possible observable implications of this effect for high-redshift galaxy clustering and reionization. Specifically we discuss in detail the effect of the relative velocity on the gas content in the early galaxies, minihaloes and the first stars. This part of the thesis also includes a concise overview of the recent studies that investigated various aspects of the relative velocity effect and showed its importance for topics ranging from star formation to precision cosmology. The third and final part of the thesis covers interaction between expanding shocks of the supernovae explosions with the interstellar medium. The shocks of supernovae remnants represent a unique cosmic environment which allows detailed studies of plasma physics and high-energy astrophysics phenomena in conditions unreachable in the Earth-based laboratories. Specifically, shocks of supernovae remnants are associated with production of cosmic rays---the most energetic particles that we can observe. In our study we are specifically focused on the science of Balmer-dominated shocks (BDS)---a subset of collisionless, fast shocks dominated by hydrogen line emission with both broad and narrow components. The unique feature of BDS is that they are directly observable and their observations provide an opportunity for direct testing of the phase space structure and ion velocity distribution inside of shocks. In this work we provide a detailed description of our computational algorithm for calculating cross sections in high-nl proton-hydrogen collisions and show results for n ≤ 4. We describe the code we developed, show the results of consistency tests and describe possible extensions. Finally, we show how our results are applied to the studies of Balmer-dominated shocks and specifically how the precise cross sections for n ≤ 4 can be used in computing Balmer decrement---the ratio of Halpha and Hbeta line intensities. (Abstract shortened by UMI.)

  15. [From Leonardo Da Vinci to present days; from the history of antiplague costume].

    PubMed

    Kalmykov, A A; Aminev, R M; Korneev, A G; Polyakov, V S; Artebyakin, S V

    2016-01-01

    As a prototype of the antiplague costume can be considered a special clothing, which physicians in medieval Europe wear for protection in plague nidus. Inventor of the first antiplague costume is considered to be a French doctor Charles de Lorme (1619). Much later, in 1878, a Russian professor Pashutin V V offered to use a costume, which looked like a hermetically sealed "bag" with a special breathing device aimed at protection of medical staff. Later, professor O.I. Dogel's respirator became well-known (1889). At the beginning of 20th century as part of the antiplague costume was used a charcoal filter mask, invented by Zelinsky N.D. Requirements to order the use of modern means of individual protection when working in nidus of especially dangerous infections identified sanitary-epidemiological rules, which reflect issues of laboratory workers working and protective clothing, respiratory protection, and view, especially operation, the procedure of putting on, removing and disinfecting antiplague costumes, pneumocostumes, pneumohelmets, isolation suits, gas-protection boxes, etc. PMID:27120957

  16. Present-day Block Motions and Strain Accumulation on Active Faults in the Caribbean

    NASA Astrophysics Data System (ADS)

    Symithe, S. J.; Calais, E.; Freed, A. M.

    2014-12-01

    The quasi-frontal subduction of the north and south American plates under the Lesser Antilles and the left and right lateral strike-slip along the northern and southern margins of the Caribbean plate offer the opportunity to study the transition from subduction to strike-slip between major plates. In addition, the segmentation and degree of interplate coupling at the Lesser Antilles subduction is key to our understanding of the earthquake potential of a subduction whose length is similar to the rupture area of the Mw9.0, 2011, Tohoku earthquake in Japan. We used the block modeling approach described in Meade and Loveless (2009) to test the optimal block geometry for the northern, eastern and southern boundaries of the Caribbean plate. We solved for angular velocities for each block/plate and strain accumulation rates for all major faults in the region. Then we calculated the variations in interplate coupling along the subduction plate boundaries using the accumulated strain rates. We tested 11 different block geometries; they are all based on geological evidences unless they are suggested by discrepancies within the GPS and seismological data or by previously published results. We confirm the existence of the micro Gonave plate. The boundary between the Micro-Gonave plate and the Hispaniola crustal block is better suited along the Haitian-Thrust-Belt instead of the Neiba-Matheux fault. The interseismic GPS velocities do not show evidence for a distinct North Lesser Antilles block. We found a totally uncoupled section of the subduction starting from the Puerto-Rico trench to the end of the Lesser Antilles section. All the relative motion of the Caribbean block is lost aseismically along the boundary of that portion of the subduction. While we found strong coupling along the northern Hispaniola section, most of the deformation on this region is being accumulated along intrablock faults with very low strain (~2mm/yr) along the intraplate subduction interface. We also performed several tests resolutions to assess the ability of the existing GPS data and the associated uncertainties to adequately resolved different aspects of the strain accumulation along the subduction. We found reasonable lateral resolution and very poor vertical resolution.

  17. US weapons secrets revealed

    SciTech Connect

    Norris, R.S.; Arkin, W.M.

    1993-03-01

    Extraordinary details have only recently been revealed about the struggle over the control of early U.S. nuclear weapons and their initial deployments abroad. The information comes from a newly declassified top secret report, part of a larger study, The History of the Strategic Arms Competition, 1945-1972, commissioned by Defense Secretary James R. Schlisinger in summer 1974.

  18. Killer-cell immunoglobulin-like receptors and cytomegalovirus reactivation during late pregnancy.

    PubMed

    Alvarado-Hernández, D L; Benítez-Sánchez, A; Rodríguez-Cuevas, J S; Rosales-Saavedra, T; Guerra-Palomares, S E; Comas-García, A; Noyola, D E; García-Sepúlveda, C A

    2016-08-01

    Human cytomegalovirus (CMV) represents an important public health concern as it is associated with severe morbidity and mortality in transplant recipients, HIV-infected individuals and pregnant women given the risk of congenital infection. Congenital CMV is a leading cause of neurological sequelae, developmental delay and birth defects worldwide. Cytomegalovirus can be transmitted to the foetus following maternal infection or reactivation. NK cells expressing killer-cell immunoglobulin-like receptors (KIR) are part of the innate immune system and the first line of defence against viral incursions. Previous reports have shown that KIR genes are associated with CMV infections in the post-transplant setting. In this study, we set out to determine whether a protective effect of KIR genes over CMV infection is seen in Mexican pregnant women. Cytomegalovirus infection was assessed through nucleic acid testing in 200 pregnant women and 600 healthy blood donors comprising the Mexican mestizo reference population. Killer-cell immunoglobulin-like receptors and HLA-C genotypes were obtained from 200 pregnant women and 300 reference samples using a comprehensive PCR-SSP approach. We observed statistically lower carrier frequencies of cB03|tA01 gene-content haplotype, of cB03 haplotype motif, of the KIR2DL5 + 2DS3/2DS5 gene pair and of KIR2DL5 amongst CMV-positive pregnant women in comparison with those CMV negative. None of these were associated with CMV status in the reference population. Logistic regression analysis revealed that the most important factor determining CMV status during third-trimester pregnancies was the KIR2DL5 + 2DS3/2DS5 gene pair (OR 0.376 (95%CI 0.174, 0.811, P = 0.013). Our results indicate that CMV-protective KIR gene associations described in Caucasoid populations are also present in the genetically distinct Mexican mestizo population. Our results suggest that certain KIR gene combinations provide protection against CMV infections occurring

  19. Revealing power in truth

    PubMed Central

    Lee, Kelley

    2015-01-01

    Jeremy Shiffman’s editorial appropriately calls on making all forms of power more apparent and accountable, notably productive power derived from expertise and claims to moral authority. This commentary argues that relationships based on productive power can be especially difficult to reveal in global health policy because of embedded notions about the nature of power and politics. Yet, it is essential to recognize that global health is shot through with power relationships, that they can take many forms, and that their explicit acknowledgement should be part of, rather than factored out of, any reform of global health governance. PMID:25844390

  20. The Universe Revealed

    NASA Astrophysics Data System (ADS)

    Spence, Pam

    1998-10-01

    The Universe is a bewildering place to the uninitiated. The concepts and theories that govern space seem complex and often contradictory. The Universe Revealed provides the keys to unlocking the wonders of the cosmos. Elegantly written and lavishly illustrated, it begins with the Sun and stretches through our solar system into deepest space. Lucid prose, written by many of the people who have shaped our current thinking on space, and spectacular photographs make the physics of the Universe accessible and provide a solid background for understanding the most recent astronomical discoveries. Covering the most intriguing features of the cosmos, the topics discussed range from the Earth and global warming to cosmic collisions and the size of the Universe. Major sections examine the Solar System, stars, galaxies, cosmology, and the observational techniques used by astronomers, both amateur and professional. The Universe Revealed represents the collaboration of internationally renowned experts in astronomy and cosmology, with contributions from authors including David Malin, F. Duccio Macchetto, Iain Nicholson, Neil Bone, Ian Ridpath, Seth Shostak, Mike Lancaster, Steve Miller, Ken Croswell, Geoff McNamara, and Steven Young. This extraordinary blend of astronomy, astrophysics, and cosmology, will appeal to amateur and armchair astronomers alike.

  1. Gusev's Rim Revealed

    NASA Technical Reports Server (NTRS)

    2004-01-01

    NASA's Mars Exploration Rover Spirit took this panoramic camera image on sol 91 (April 5, 2004). Spirit is looking to the southeast, and through the martian haze has captured the rim of Gusev Crater approximately 80 kilometers (49.7 miles) away on the horizon.

    The right side of this image reveals the portion of the crater edge that descends into the mouth of Ma'adim Vallis, a channel that opens into Gusev Crater. Spirit is currently traveling toward the informally named 'Columbia Hills,' which lie to the left of the region pictured here.

    This image is similar to a panoramic camera image taken on sol 68, but Gusev's ridge is more visible here because the atmospheric dust caused by winter dust storms has settled. Scientists expect to get even clearer images than this one in upcoming sols.

    This image has been modified to make the crater rim more visible.

  2. Titan Casts Revealing Shadow

    NASA Astrophysics Data System (ADS)

    2004-05-01

    A rare celestial event was captured by NASA's Chandra X-ray Observatory as Titan -- Saturn's largest moon and the only moon in the Solar System with a thick atmosphere -- crossed in front of the X-ray bright Crab Nebula. The X-ray shadow cast by Titan allowed astronomers to make the first X-ray measurement of the extent of its atmosphere. On January 5, 2003, Titan transited the Crab Nebula, the remnant of a supernova explosion that was observed to occur in the year 1054. Although Saturn and Titan pass within a few degrees of the Crab Nebula every 30 years, they rarely pass directly in front of it. "This may have been the first transit of the Crab Nebula by Titan since the birth of the Crab Nebula," said Koji Mori of Pennsylvania State University in University Park, and lead author on an Astrophysical Journal paper describing these results. "The next similar conjunction will take place in the year 2267, so this was truly a once in a lifetime event." Animation of Titan's Shadow on Crab Nebula Animation of Titan's Shadow on Crab Nebula Chandra's observation revealed that the diameter of the X-ray shadow cast by Titan was larger than the diameter of its solid surface. The difference in diameters gives a measurement of about 550 miles (880 kilometers) for the height of the X-ray absorbing region of Titan's atmosphere. The extent of the upper atmosphere is consistent with, or slightly (10-15%) larger, than that implied by Voyager I observations made at radio, infrared, and ultraviolet wavelengths in 1980. "Saturn was about 5% closer to the Sun in 2003, so increased solar heating of Titan may account for some of this atmospheric expansion," said Hiroshi Tsunemi of Osaka University in Japan, one of the coauthors on the paper. The X-ray brightness and extent of the Crab Nebula made it possible to study the tiny X-ray shadow cast by Titan during its transit. By using Chandra to precisely track Titan's position, astronomers were able to measure a shadow one arcsecond in

  3. Revealing the Beast Within

    NASA Astrophysics Data System (ADS)

    2003-07-01

    Deeply Embedded Massive Stellar Clusters Discovered in Milky Way Powerhouse Summary Peering into a giant molecular cloud in the Milky Way galaxy - known as W49 - astronomers from the European Southern Observatory (ESO) have discovered a whole new population of very massive newborn stars . This research is being presented today at the International Astronomical Union's 25th General Assembly held in Sydney, Australia, by ESO-scientist João Alves. With the help of infrared images obtained during a period of excellent observing conditions with the ESO 3.5-m New Technology Telescope (NTT) at the La Silla Observatory (Chile), the astronomers looked deep into this molecular cloud and discovered four massive stellar clusters, with hot and energetic stars as massive as 120 solar masses. The exceedingly strong radiation from the stars in the largest of these clusters is "powering" a 20 light-year diameter region of mostly ionized hydrogen gas (a "giant HII region"). W49 is one of the most energetic regions of star formation in the Milky Way. With the present discovery, the true sources of the enormous energy have now been revealed for the first time, finally bringing to an end some decades of astronomical speculations and hypotheses. PR Photo 21a/03 : Colour Composite of W49A (NTT+SOFI). PR Photo 21b/03 : Radio and Near-Infrared Composite of W49A Giant molecular clouds Stars form predominantly inside Giant Molecular Clouds which populate our Galaxy, the Milky Way. One of the most prominent of these is W49 , which has a mass of a million solar masses. It is located some 37,000 light-years away and is the most luminous star-forming region known in our home galaxy: its luminosity is several million times the luminosity of our Sun. A smaller region within this cloud is denoted W49A - this is one of the strongest radio-emitting areas known in the Galaxy . Massive stars are excessive in all ways. Compared to their smaller and ligther brethren, they form at an Olympic speed and

  4. rs3918242 MMP9 gene polymorphism is associated with myocardial infarction in Mexican patients.

    PubMed

    Rodríguez-Pérez, J M; Vargas-Alarcón, G; Posadas-Sánchez, R; Zagal-Jiménez, T X; Ortíz-Alarcón, R; Valente-Acosta, B; Tovilla-Zárate, C; Nostroza-Hernández, C; Pérez-Méndez, O; Pérez-Hernández, N

    2016-01-01

    Several studies have demonstrated that matrix metalloproteinases (MMPs) play a major role in atherosclerotic plaque disruption and lead to myocardial infarction (MI). We investigated the association between the MMP1 -1607 1G/2G (rs1799750), MMP3 -1612 5A/6A (rs3025058), and MMP9 -1562 C/T (rs3918242) polymorphisms and the risk of developing MI in a Mexican mestizo cohort. The genotype analysis was performed using the restriction fragment length polymorphism-polymerase chain reaction technique in a group of 236 patients with a history of MI and 285 healthy controls. Similar distributions of rs1799750 and rs3025058 were observed in both groups; however, the MMP9 rs3918242 T allele and the CT genotype were associated with the risk of developing MI (OR = 2.32, pC = 0.02 and OR = 2.40, pC = 0.02, respectively). Multiple logistic analysis was performed between MI patients and controls to estimate the risk, and after adjusting for identified risk factors, the CT + TT genotypes of MMP9 rs3918242 were found to be significantly associated with increased risk of developing MI than those with the CC genotype (OR = 2.88, P < 0.01). In summary, our results reveal that the rs3918242 polymorphism of the MMP9 gene plays a major role in the risk of developing MI. PMID:26985929

  5. Phylogenetic diversity as a window into the evolutionary and biogeographic histories of present-day richness gradients for mammals

    PubMed Central

    Davies, T. Jonathan; Buckley, Lauren B.

    2011-01-01

    Phylogenetic diversity (PD) captures the shared ancestry of species, and is increasingly being recognized as a valuable conservation currency. Regionally, PD frequently covaries closely with species richness; however, variation in speciation and extinction rates and/or the biogeographic history of lineages can result in significant deviation. Locally, these differences may be pronounced. Rapid recent speciation or high temporal turnover of lineages can result in low PD but high richness. In contrast, rare dispersal events, for example, between biomes, can elevate PD but have only small impact on richness. To date, environmental predictors of species richness have been well studied but global models explaining variation in PD are lacking. Here, we contrast the global distribution of PD versus species richness for terrestrial mammals. We show that an environmental model of lineage diversification can predict well the discrepancy in the distribution of these two variables in some places, for example, South America and Africa but not others, such as Southeast Asia. When we have information on multiple diversity indices, conservation efforts directed towards maximizing one currency or another (e.g. species richness versus PD) should also consider the underlying processes that have shaped their distributions. PMID:21768156

  6. Adult medulloblastoma, from spongioblastoma cerebelli to the present day: a review of treatment and the integration of molecular markers.

    PubMed

    Shonka, Nicole; Brandes, Alba; De Groot, John F

    2012-11-01

    Although they represent the most common malignant brain tumor in the pediatric population, medulloblastomas are rare in adults, with an incidence of 0.5 per million. With only one exception, all of the prospective clinical trials in this disease have been done in the pediatric population, and therefore therapy for adult medulloblastoma has been either extrapolated from the pediatric literature or based on retrospective reviews. A growing body of literature underscores the genetic similarities between adult and pediatric disease, which may allow tailored therapy directed towards specific molecular pathways and may have an impact on clinical outcomes. Here we present the history, staging system, and treatment of medulloblastoma, reviewing the prognostic value and clinical application of molecular subtyping while highlighting the differences between adult and pediatric disease. PMID:23330353

  7. Present-day velocity and stress fields of the Amurian plate from thin-shell finite element modelling

    NASA Astrophysics Data System (ADS)

    Petit, C.; Fournier, M.

    2003-04-01

    Space geodetic data have shown that east of longitude 100°E, the southeastern and eastern Asia including Sundaland, South China, North China, and the Amurian plate move eastward at a mean rate of 1 cm/yr relative to Siberia. The relative motions between the main continental blocks of eastern Asia are low, of the order of 1-2 mm/yr. Thus, a wide region extending from the Baikal Rift to the Japan Sea and to SE Asia and Indonesia is slowly extruded eastward at a rate of ~1 cm/yr. It is generally admitted that eastward extrusion of such continental blocks accounts for 1/4 to 1/3 of deformation in Asia, while the remaining 2/3 to 3/4 are accommodated by crustal and/or lithospheric thickening. As a consequence, any dynamic model of deformation in Asia should take into account body forces due to plate thickening as well as boundary forces coming from the India-Asia collision and Pacific subductions. We present spherical thin-plate models of the Amurian continental plate using the finite element code SHELLS developed by Peter Bird (1999). This 2D modelling code simulates short-term deformation of a 2-layered lithosphere with lateral variations of crustal and lithospheric thicknesses, and heat flow. We first analyze the Amurian plate kinematics and deformation through GPS and seismotectonic data. Then we use the finite element model to define the boundary conditions that best match the observed velocity and stress fields. The best-fitting model involves a transition from NW-SE compression to eastward extrusion along the southern plate boundary, favoring the opening of the Baikal rift east of 105°E. NE-SW to EW compression along the eastern plate limit is satisfyingly reproduced by the relative motions of the Okhotsk, Pacific and Philippine Sea plates. Finally, we show that body forces due to sharp changes in crustal and lithospheric thicknesses can explain the rapid transition from NE-SW extension in the north Baikal rift to ~NS compression in the Stanovoy range.

  8. Landau ghost pole problem in quantum field theory: From 50th of last century to the present day

    NASA Astrophysics Data System (ADS)

    Jafarov, Rauf G.; Mutallimov, Mutallim M.

    2016-03-01

    In this paper we present our results of the investigation of asymptotical behavior of amplitude at short distances in four-dimensional scalar field theory with ϕ4 interaction. To formulate of our calculating model - two-particle approximation of the mean-field expansion we have used an Rochev's iteration scheme of solution of the Schwinger-Dyson equations with the fermion bilocal source. We have considered the nonlinear integral equations in deep-inelastic region of momenta. As result we have a non-trivial behavior of amplitude at large momenta.

  9. Do MAGSAT anomalies contain a record of past and present-day mantle convection under South America?

    NASA Technical Reports Server (NTRS)

    Hastings, D. A.

    1985-01-01

    Global anomaly maps from the National Aeronautics and Space Administration's Magnetic Field Satellite (MAGSAT) have been spatially filtered to reduce the prominence of long-wavelength east-west bands and to improve the discrimination of anomalies within structural provinces. Previous research suggested a correlation between total-field MAGSAT anomaly lows in equatorial regions with crustal bodies of relatively high average magnetic susceptibility (such as Archaean shields), and of anomaly highs with bodies of low susceptibility (such as deep parts of basins). These correlations reverse at higher latitudes.

  10. Paleobotanical Evidence for Near Present-Day Levels of Atmospheric CO2 During Part of the Tertiary

    NASA Astrophysics Data System (ADS)

    Royer, Dana L.; Wing, Scott L.; Beerling, David J.; Jolley, David W.; Koch, Paul L.; Hickey, Leo J.; Berner, Robert A.

    2001-06-01

    Understanding the link between the greenhouse gas carbon dioxide (CO2) and Earth's temperature underpins much of paleoclimatology and our predictions of future global warming. Here, we use the inverse relationship between leaf stomatal indices and the partial pressure of CO2 in modern Ginkgo biloba and Metasequoia glyptostroboides to develop a CO2 reconstruction based on fossil Ginkgo and Metasequoia cuticles for the middle Paleocene to early Eocene and middle Miocene. Our reconstruction indicates that CO2 remained between 300 and 450 parts per million by volume for these intervals with the exception of a single high estimate near the Paleocene/Eocene boundary. These results suggest that factors in addition to CO2 are required to explain these past intervals of global warmth.

  11. Present-Day Rates of Deformation Across the Southern Walker Lane From a Densified Regional GPS Network

    NASA Astrophysics Data System (ADS)

    Lifton, Z. M.; Frankel, K. L.; Newman, A. V.; Foy, T. A.; Feng, L.; Johnson, C.; Dixon, T. H.

    2010-12-01

    The Walker Lane is a diffuse region of right-lateral shear in western Nevada and eastern California that accommodates ~25% (9.3 ± 0.2 mm/yr) of the relative motion between the Pacific and North American plates. The region is characterized by discontinuous NNW-trending right-lateral strike-slip faults, and NE-trending, down-to-the-NW normal faults. The late Quaternary cumulative slip across the southern Walker Lane is only 1/3 the observed regional geodetic rate of right-lateral shear. We address this discrepancy between geologic and modern geodetic rates by installing and surveying a denser network of GPS monuments than previously existed. The higher spatial resolution will allow us to better define deformation rates in this complex tectonic setting. Our GPS data will be combined with accompanying fault kinematic and geochronologic data to determine deformation rates across multiple time scales, from late Quaternary to the present. We conducted a campaign GPS survey covering approximately 10,000 square kilometers encompassing the White Mountains, Fish Lake Valley, Clayton Valley, and the Silver Peak Range. We occupied 23 sites, including 10 newly installed monuments, which are spaced approximately 15-20 km apart. The existing sites used in this survey include the UNR-NEARNET sites, as well as a number of other campaign networks archived at UNAVCO. Stations with the longest history (including sites first surveyed as early as 1992) are expected to yield the most accurate results, while newer sites will help identify spatial patterns of strain partitioning. Monuments will be reoccupied annually and combined with past campaign survey data to determine modern crustal velocities. Initial results from this survey will be presented, which have important implications for understanding strain distribution along this important segment of the Pacific-North America boundary.

  12. Present day and geologic deformation rates in the Ardenne and the lower Rhine embayment (North-western Europe)

    NASA Astrophysics Data System (ADS)

    van Camp, M.; Camelbeeck, T.; Vanneste, K.; Warnant, R.

    2003-04-01

    In the Roer Graben and the Belgian Ardenne, there is a difference of an order of magnitude in the inferred vertical crustal movements deduced on one side from geological information (0.1 mm/yr) and on the other side from repeated levellings since the end of the 19th century (~1 mm/yr). We present a new analysis of the repeated levellings: generally, they are not significant enough to infer actual vertical ground displacements. We also reconsider the interpretation of the significant measurements with crustal movements: observed vertical movements in areas with a thick cover of unconsolidated sediments, which is generally the case in the Roer Valley Graben, can be related to the local geological conditions rather than to true crustal movements. An example is the man-made subsidence induced by water pumping to prevent large open-cast mines in Germany from being flooded, observed by repeated levellings, GPS, INSAR and gravity measurements. To measure the present crustal deformations for the interpretation of the slip rates along the active-faults in the Lower-Rhine Embayment, we have performed two very-long-term experiments. First, continuous measurements of the movements across the Feldbiss fault have been recorded by two GPS permanent stations (Bree &Meeuwen) on either side of the fault since 1997. No observable relative vertical (horizontal resp.) movement larger than 0.5 mm/yr (0.3 mm/yr resp.) has been observed for the last 5 years. These values are already less than the results deduced from repeated levellings. Secondly, since 1999, we undertook a series of biannual campaigns of absolute gravity measurements (AG) along an 8-station profile running over 140 km across the Ardenne and the Roer valley rift system. We present the first results and they show that, in all the stations but Jülich, there is no detectable gravity rate of change larger than 2 µGal/yr. This is equivalent to an uplift of 10 mm/yr, using a deformational gradient of -0.2 µGal/mm. Jülich lies in the Roer valley and suffers from man-induced subsidence, where a gravity rate of change of 3.1+/-1.9 µGal/yr is observed. To ensure that the absolute gravimeter is giving accurate results it has been compared regularly with the superconducting gravimeter installed at the Membach reference station, which belongs to the profile. There, a low trend in gravity of -0.44+/-0.10 µGal/year is observed among 80 AG measurements since 1996. In particular, we show a good correlation between the gravity measurements and the continuous GPS measurements performed since 1997 at 3 km from the station. We compare these measurements with those recorded at the two other stations at Bree and Meeuwen, and discuss the results. The observed crustal deformations, which must be confirmed, could be linked to active faults in the Ardenne and/or bordering the Roer Valley Graben, or perhaps also to the post-glacial rebound or to the Eifel plume.

  13. Neopositivism and the DSM psychiatric classification. An epistemological history. Part 2: Historical pathways, epistemological developments and present-day needs.

    PubMed

    Aragona, Massimiliano

    2013-12-01

    Little is known about the concrete historical sources for the use of neopositivist operational criteria by the DSM-III. This paper suggests that distinct sources operated implicitly. The current usefulness of the operational approach is questioned. It is shown that: (a) in epistemology, neopositivism has been replaced by more adequate accounts; (b) psychologists rejected operational definitions because these were unable to define the majority of mental phenomena; (c) mental symptoms cannot be directly described as such, because they already make part of the psychiatric diagnosis to which they belong. In conclusion, diagnosing is based on the hermeneutical co-construction of mental symptoms. The failure of the neopositivist programme suggests that it is time to reconcile scientific formalization and semiotic activity. PMID:24573752

  14. Present-day challenges and future solutions in postoperative pain management: results from PainForum 2014

    PubMed Central

    Kuusniemi, Kristiina; Pöyhiä, Reino

    2016-01-01

    This paper is a summary of presentations on postoperative pain control by the authors at the 2014 PainForum meeting in People’s Republic of China. Postoperative pain is often untreated or undertreated and may lead to subsequent chronic pain syndromes. As more procedures migrate to the outpatient setting, postoperative pain control will become increasingly more challenging. Evidence-based guidelines for postoperative pain control recommend pain assessment using validated tools on a consistent basis. In this regard, consistency may be more important than the specific tool selected. Many hospitals have introduced a multidisciplinary acute pain service (APS), which has been associated with improved patient satisfaction and fewer adverse events. Patient education is an important component of postoperative pain control, which may be most effective when clinicians chose a multimodal approach, such as paracetamol (acetaminophen) and opioids. Opioids are a mainstay of postoperative pain control but require careful monitoring and management of side effects, such as nausea, vomiting, dizziness, and somnolence. Opioids may be administered using patient-controlled analgesia systems. Protocols for postoperative pain control can be very helpful to establish benchmarks for pain management and assure that clinicians adhere to evidence-based standards. The future of postoperative pain control around the world will likely involve more and better established APSs and greater communication between patients and clinicians about postoperative pain. The changes necessary to implement and move forward with APSs is not a single step but rather one of continuous improvement and ongoing change. PMID:26893579

  15. On the flow of a compressible fluid by the hodograph method I : unification and extension of present-day results

    NASA Technical Reports Server (NTRS)

    Garrick, I E; Kaplan, Carl

    1944-01-01

    Elementary basic solutions of the equations of motion of a compressible fluid in the hodograph variables are developed and used to provide a basis for comparison, in the form of velocity correction formulas, of corresponding compressible and incompressible flows. The known approximate results of Chaplygin, Von Karman and Tsien, Temple and Yarwood, and Prandtl and Glauert are unified by means of the analysis of the present paper. Two new types of approximations, obtained from the basic solutions, are introduced; they possess certain desirable features of the other approximations and appear preferable as a basis for extrapolation into the range of high stream Mach numbers and large disturbances to the main stream. Tables and figures giving velocity and pressure-coefficient correction factors are included in order to facilitate the practical application of the results.

  16. FY 2011 Second Quarter: Demonstration of New Aerosol Measurement Verification Testbed for Present-Day Global Aerosol Simulations

    SciTech Connect

    Koch, D

    2011-03-20

    The regional-scale Weather Research and Forecasting (WRF) model is being used by a DOE Earth System Modeling (ESM) project titled “Improving the Characterization of Clouds, Aerosols and the Cryosphere in Climate Models” to evaluate the performance of atmospheric process modules that treat aerosols and aerosol radiative forcing in the Arctic. We are using a regional-scale modeling framework for three reasons: (1) It is easier to produce a useful comparison to observations with a high resolution model; (2) We can compare the behavior of the CAM parameterization suite with some of the more complex and computationally expensive parameterizations used in WRF; (3) we can explore the behavior of this parameterization suite at high resolution. Climate models like the Community Atmosphere Model version 5 (CAM5) being used within the Community Earth System Model (CESM) will not likely be run at mesoscale spatial resolutions (10–20 km) until 5–10 years from now. The performance of the current suite of physics modules in CAM5 at such resolutions is not known, and current computing resources do not permit high-resolution global simulations to be performed routinely. We are taking advantage of two tools recently developed under PNNL Laboratory Directed Research and Development (LDRD) projects for this activity. The first is the Aerosol Modeling Testbed (Fast et al., 2011b), a new computational framework designed to streamline the process of testing and evaluating aerosol process modules over a range of spatial and temporal scales. The second is the CAM5 suite of physics parameterizations that have been ported into WRF so that their performance and scale dependency can be quantified at mesoscale spatial resolutions (Gustafson et al., 2010; with more publications in preparation).

  17. Reversing Present Day Northern Plains Ecosystem Water Supply Stressors Resulting from the Near Extinction of Three Keystone Species

    NASA Astrophysics Data System (ADS)

    Collins, M. R.

    2006-05-01

    Near-extinction of three keystone species (the beaver, the bison, and the prairie dog) had a measurable negative influence on the local and regional climate, and water availability in the Northern Great Plains ecosystem compared to pre-contact conditions. Restoration of these three keystone species may have a significant positive influence by increasing the recharge rate to the aquifers and raising soil moisture due to the sharp hooves and wallows of the bison, prairie dog burrows, and beaver dams providing avenues of ingress. Predictions 1) The recharge of the aquifer will be greater where these three keystone species are present because of the prairie dog burrows, buffalo hooves and wallows, and beaver dams in comparison to the control area; 2) The entire ecosystem will be rejuvenated where the three species are permitted to return; 3) The microclimate changes caused by this reintroduction will stimulate an observable, measurable improvement in water supply when allowed to proceed to near pre-contact conditions. Next Steps 1) Inventory research area containing bison, prairie dog, and beaver versus control plot. (keystone species absent). 2) Measure the soil moisture, water table, water influx rates. 3) Monitor changes over time. 4) Later phase manipulation: Beaver re-introduction into severely damaged riparian area. 5) Link to Northern Plains NEON Initiative. Current Activity 1. Candidate study locations on Standing Rock reservation have been selected and evaluated for suitability, both as study site with beaver activity and a control site with beaver absent. 2. Research mentor identified and selected. Dr. Carol Johnston of South Dakota State University, Director of the Center for Biocomplexity Studies has graciously agreed to oversee my research project 3. Review of previous work is nearing completion. 4. Tribal Agency personnel currently involved with research related to the three keystone species have been interviewed and information obtained from them regarding prairie dog behavior and burrow morphology.

  18. Soil mapping and modelling for evaluation of the effects of historical and present-day soil erosion

    NASA Astrophysics Data System (ADS)

    Smetanova, Anna; Szwarczewski, Piotr

    2016-04-01

    The loess hilly lands in Danube Lowland are characterized by patchy soil-scape. The soil erosion processes uncover the subsurface, bright loess horizon, while non-eroded and colluvial soils are of the dark colour, in the chernozem area. With the modernisation of agriculture since the 1950's and in the process of collectivization, when small fields were merged into bigger, the soil degradation progressed. However, the analysis of historical sources and sediment archives showed the proofs of historical soil erosion. The objective of this study is to map the soil erosion patterns in connection of both pre- and post-collectivization landscape and to understand the accordingly developed soil erosion patterns. The combined methods of soil mapping and soil erosion modelling were applied in the part of the Trnavska pahorkatina Hilly Land in Danube Lowland. The detailed soil mapping in a zero-order catchment (0.28 km²) uncovered the removal of surface soil horizon of 0.6m or more, while the colluvial soils were about 1.1m deep. The soil properties and dating helped to describe the original soil profile in the valley bottom, and reconstruct the history of soil erosion in the catchment. The soil erosion model was applied using the reconstructed land use patterns in order to understand the effect of recent and historical soil erosion in the lowland landscape. This work was supported by the Slovak Research and Development Agency under the contract ESF-EC-0006-07 and APVV-0625-11; Anna Smetanová has received the support of the AgreenSkills fellowship (under grant agreement n°267196).

  19. Modeling of present-day atmosphere and ocean non-tidal de-aliasing errors for future gravity mission simulations

    NASA Astrophysics Data System (ADS)

    Dobslaw, Henryk; Bergmann-Wolf, Inga; Forootan, Ehsan; Dahle, Christoph; Mayer-Gürr, Torsten; Kusche, Jürgen; Flechtner, Frank

    2016-05-01

    A realistically perturbed synthetic de-aliasing model consistent with the updated Earth System Model of the European Space Agency is now available over the period 1995-2006. The dataset contains realizations of (1) errors at large spatial scales assessed individually for periods 10-30, 3-10, and 1-3 days, the S1 atmospheric tide, and sub-diurnal periods; (2) errors at small spatial scales typically not covered by global models of atmosphere and ocean variability; and (3) errors due to physical processes not represented in currently available de-aliasing products. The model is provided in two separate sets of Stokes coefficients to allow for a flexible re-scaling of the overall error level to account for potential future improvements in atmosphere and ocean mass variability models. Error magnitudes for the different frequency bands are derived from a small ensemble of four atmospheric and oceanic models. For the largest spatial scales up to d/o = 40 and periods longer than 24 h, those error estimates are approximately confirmed from a variance component estimation based on GRACE daily normal equations. Future mission performance simulations based on the updated Earth System Model and the realistically perturbed de-aliasing model indicate that for GRACE-type missions only moderate reductions of de-aliasing errors can be expected from a second satellite pair in a shifted polar orbit. Substantially more accurate global gravity fields are obtained when a second pair of satellites in an moderately inclined orbit is added, which largely stabilizes the global gravity field solutions due to its rotated sampling sensitivity.

  20. Relationships between pore pressure, stresses, and present-day geodynamics in the Scotian Shelf, offshore eastern Canada

    SciTech Connect

    Yassir, N.A.; Bell, J.S.

    1994-12-01

    A geomechanical study of the Mesozoic and Tertiary sediments beneath the Scotian Shelf shows that two major weak layers exist at depth: the over-pressured unit at 4000 m and the basal Argo salt, which is ductile and diapiric. A consistent relationships is observed between the overpressures and the stress state in the basin. First, the smaller horizontal principal stress increases dramatically just above the onset of overpressuring, and secondly, borehole breakouts, indicators of stress anisotropy-decrease in abundance within the overpressure zone. Neither tectonic shear nor rapid burial can explain these observations; however, overpressuring by fluid generation will result in horizontal stress increase and eventually lead to an isotropic stress state. Compelling evidence is found for hydrocarbon generation being a key cause of overpressuring in the Scotian Shelf.

  1. Impact of preindustrial to present-day changes in short-lived pollutant emissions on atmospheric composition and climate forcing

    NASA Astrophysics Data System (ADS)

    Naik, Vaishali; Horowitz, Larry W.; Fiore, Arlene M.; Ginoux, Paul; Mao, Jingqiu; Aghedo, Adetutu M.; Levy, Hiram

    2013-07-01

    We describe and evaluate atmospheric chemistry in the newly developed Geophysical Fluid Dynamics Laboratory chemistry-climate model (GFDL AM3) and apply it to investigate the net impact of preindustrial (PI) to present (PD) changes in short-lived pollutant emissions (ozone precursors, sulfur dioxide, and carbonaceous aerosols) and methane concentration on atmospheric composition and climate forcing. The inclusion of online troposphere-stratosphere interactions, gas-aerosol chemistry, and aerosol-cloud interactions (including direct and indirect aerosol radiative effects) in AM3 enables a more complete representation of interactions among short-lived species, and thus their net climate impact, than was considered in previous climate assessments. The base AM3 simulation, driven with observed sea surface temperature (SST) and sea ice cover (SIC) over the period 1981-2007, generally reproduces the observed mean magnitude, spatial distribution, and seasonal cycle of tropospheric ozone and carbon monoxide. The global mean aerosol optical depth in our base simulation is within 5% of satellite measurements over the 1982-2006 time period. We conduct a pair of simulations in which only the short-lived pollutant emissions and methane concentrations are changed from PI (1860) to PD (2000) levels (i.e., SST, SIC, greenhouse gases, and ozone-depleting substances are held at PD levels). From the PI to PD, we find that changes in short-lived pollutant emissions and methane have caused the tropospheric ozone burden to increase by 39% and the global burdens of sulfate, black carbon, and organic carbon to increase by factors of 3, 2.4, and 1.4, respectively. Tropospheric hydroxyl concentration decreases by 7%, showing that increases in OH sinks (methane, carbon monoxide, nonmethane volatile organic compounds, and sulfur dioxide) dominate over sources (ozone and nitrogen oxides) in the model. Combined changes in tropospheric ozone and aerosols cause a net negative top-of-the-atmosphere radiative forcing perturbation (-1.05 W m-2) indicating that the negative forcing (direct plus indirect) from aerosol changes dominates over the positive forcing due to ozone increases, thus masking nearly half of the PI to PD positive forcing from long-lived greenhouse gases globally, consistent with other current generation chemistry-climate models.

  2. Cervical cancer narratives: invoking 'God's will' to re-appropriate reproductive rights in present-day Romania.

    PubMed

    Pop, Cristina A

    2015-01-01

    Drawing from ethnographic fieldwork in contemporary Southern Romania, this paper scrutinises local moralities governing some women's refusal to enrol in free reproductive healthcare initiatives targeting cervical cancer through primary and secondary prevention (human papillomavirus [HPV] vaccination and Papanicolaou [Pap] testing, respectively). Women backed up their rejection of participation in official reproductive care programmes by mentioning 'God's will' as the ultimate trigger of cervical cancer. They withheld their own and their daughters' bodies from biomedical intervention and used discursive references to divine logic to imbue their refusal with moral legitimacy. However, 'God's will' is not a mere rhetorical device, since it has a correlate in many of these women's embodied reproductive experiences. As this paper argues, religious narratives, far from stripping ordinary citizens of their reproductive choices, constitute the medium through which they display individual agency. In fact, invoking 'God's will' empowers Romanian women to challenge state control and it enables them to re-appropriate their bodies by making a counter-intuitive, yet bold, choice. PMID:25175839

  3. Stable lead isotope compositions in selected coals from around the world and implications for present day aerosol source tracing

    SciTech Connect

    M. Diaz-Somoano; M.E. Kylander; M.A. Lopez-Anton; I. Suarez-Ruiz; M.R. Martinez-Tarazona; M. Ferrat; B. Kober; D.J. Weiss

    2009-02-15

    The phasing out of leaded gasoline in many countries around the world at the end of the last millennium has resulted in a complex mixture of lead sources in the atmosphere. Recent studies suggest that coal combustion has become an important source of Pb in aerosols in urban and remote areas. Lead concentration and isotopic composition is reported for 59 coal samples representing major coal deposits worldwide in an attempt to characterize this potential source. The average concentration in these coals is 35 {mu}g Pb g{sup -1}, with the highest values in coals from Spain and Peru and the lowest in coals from Australia and North America. The {sup 206}Pb/{sup 207}Pb isotope ratios range between 1.15 and 1.24, with less radiogenic Pb in coals from Europe and Asia compared to South and North America. Comparing the Pb isotopic signatures of coals from this and previous studies with those published for Northern and Southern Hemisphere aerosols, we hypothesize that coal combustion might now be an important Pb source in China, the eastern U.S., and to some extent, in Europe but not as yet in other regions including South Africa, South America, and western U.S. This supports the notion that 'old Pb pollution' from leaded gasoline reemitted into the atmosphere or long-range transport (i.e., from China to the western U.S.) is important. Comparing the isotope ratios of the coals, the age of the deposits, and Pb isotope evolution models for the major geochemical reservoirs suggests that the lead isotope ratios (PbIC) in coals is strongly influenced by the depositional coal forming environment. 47 refs., 3 figs., 1 tab.

  4. Water vapor changes under global warming and the linkage to present-day interannual variabilities in CMIP5 models

    NASA Astrophysics Data System (ADS)

    Takahashi, Hanii; Su, Hui; Jiang, Jonathan H.

    2016-03-01

    The fractional water vapor changes under global warming across 14 Coupled Model Intercomparison Project Phase 5 simulations are analyzed. We show that the mean fractional water vapor changes under global warming in the tropical upper troposphere between 300 and 100 hPa range from 12.4 to 28.0 %/K across all models while the fractional water vapor changes are about 5-8 %/K in other regions and at lower altitudes. The "upper-tropospheric amplification" of the water vapor change is primarily driven by a larger temperature increase in the upper troposphere than in the lower troposphere per degree of surface warming. The relative contributions of atmospheric temperature and relative humidity changes to the water vapor change in each model vary between 71.5 to 131.8 % and 24.8 to -20.1 %, respectively. The inter-model differences in the water vapor change is primarily caused by differences in temperature change, except over the inter-tropical convergence zone within 10°S-10°N where the model differences due to the relative humidity change are significant. Furthermore, we find that there is generally a positive correlation between the rates of water vapor change for long-tem surface warming and those on the interannual time scales. However, the rates of water vapor change under long-term warming have a systematic offset from those on the inter-annual time scales and the dominant contributor to the differences also differs for the two time scales, suggesting caution needs to be taken when inferring long-term water vapor changes from the observed interannual variations.

  5. Reconstruction of Oomycete Genome Evolution Identifies Differences in Evolutionary Trajectories Leading to Present-Day Large Gene Families

    PubMed Central

    Seidl, Michael F.; Van den Ackerveken, Guido; Govers, Francine; Snel, Berend

    2012-01-01

    The taxonomic class of oomycetes contains numerous pathogens of plants and animals but is related to nonpathogenic diatoms and brown algae. Oomycetes have flexible genomes comprising large gene families that play roles in pathogenicity. The evolutionary processes that shaped the gene content have not yet been studied by applying systematic tree reconciliation of the phylome of these species. We analyzed evolutionary dynamics of ten Stramenopiles. Gene gains, duplications, and losses were inferred by tree reconciliation of 18,459 gene trees constituting the phylome with a highly supported species phylogeny. We reconstructed a strikingly large last common ancestor of the Stramenopiles that contained ∼10,000 genes. Throughout evolution, the genomes of pathogenic oomycetes have constantly gained and lost genes, though gene gains through duplications outnumber the losses. The branch leading to the plant pathogenic Phytophthora genus was identified as a major transition point characterized by increased frequency of duplication events that has likely driven the speciation within this genus. Large gene families encoding different classes of enzymes associated with pathogenicity such as glycoside hydrolases are formed by complex and distinct patterns of duplications and losses leading to their expansion in extant oomycetes. This study unveils the large-scale evolutionary dynamics that shaped the genomes of pathogenic oomycetes. By the application of phylogenetic based analyses methods, it provides additional insights that shed light on the complex history of oomycete genome evolution and the emergence of large gene families characteristic for this important class of pathogens. PMID:22230142

  6. Effect of carbonic anhydrase on silicate weathering and carbonate formation at present day CO2 concentrations compared to primordial values

    PubMed Central

    Xiao, Leilei; Lian, Bin; Hao, Jianchao; Liu, Congqiang; Wang, Shijie

    2015-01-01

    It is widely recognized that carbonic anhydrase (CA) participates in silicate weathering and carbonate formation. Nevertheless, it is still not known if the magnitude of the effect produced by CA on surface rock evolution changes or not. In this work, CA gene expression from Bacillus mucilaginosus and the effects of recombination protein on wollastonite dissolution and carbonate formation under different conditions are explored. Real-time fluorescent quantitative PCR was used to explore the correlation between CA gene expression and sufficiency or deficiency in calcium and CO2 concentration. The results show that the expression of CA genes is negatively correlated with both CO2 concentration and ease of obtaining soluble calcium. A pure form of the protein of interest (CA) is obtained by cloning, heterologous expression, and purification. The results from tests of the recombination protein on wollastonite dissolution and carbonate formation at different levels of CO2 concentration show that the magnitudes of the effects of CA and CO2 concentration are negatively correlated. These results suggest that the effects of microbial CA in relation to silicate weathering and carbonate formation may have increased importance at the modern atmospheric CO2 concentration compared to 3 billion years ago. PMID:25583135

  7. Bridging onshore and offshore present-day kinematics of central and eastern Mediterranean: Implications for crustal dynamics and mantle flow

    NASA Astrophysics Data System (ADS)

    PéRouse, EugéNie; Chamot-Rooke, Nicolas; Rabaute, Alain; Briole, Pierre; Jouanne, FrançOis; Georgiev, Ivan; Dimitrov, Dimitar

    2012-09-01

    We present a new kinematic and strain model of an area encompassing the Calabrian and Hellenic subduction zones, western Anatolia and the Balkans. Using Haines and Holt's (1993) method, we derive continuous velocity and strain rate fields by interpolating geodetic velocities, including recent GPS data in the Balkans. Relative motion between stable Eurasia and the western Aegean Sea is gradually accommodated by distributed N-S extension from Southern Balkans to the Eastern Corinth Gulf, so that the westward propagation of the North Anatolian Fault (NAF) throughout continental Greece or Peloponnesus is not required. We thus propose that the NAF terminates in north Aegean and that N-S extension localized in the Corinth Gulf and distributed in Southern Balkans is due to the retreat of the Hellenic slab. The motion of the Hyblean plateau, Apulia Peninsula, south Adriatic Sea, Ionian Basin and Sirte plain can be minimized by a single rigid rotation around a pole located in the Sirte plain, compatible with the opening the Pelagian rifts (2-2.5 mm/yr) and seismotectonics in Libya. We interpret the trenchward ultraslow motion of the Calabrian arc (2-2.5 mm/yr) as pure collapse, the Calabrian subduction being now inactive. In the absolute plate motion reference frame, our modeled velocity field depicts two toroïdal crustal patterns located at both ends of the Hellenic subduction zone, clockwise in NW Greece and counter-clockwise in western Anatolia. We suggest the NW Greece toroïdal pattern is the surface expression of a slab tear and consequent toroïdal asthenospheric flow.

  8. Effect of carbonic anhydrase on silicate weathering and carbonate formation at present day CO2 concentrations compared to primordial values

    NASA Astrophysics Data System (ADS)

    Xiao, Leilei; Lian, Bin; Hao, Jianchao; Liu, Congqiang; Wang, Shijie

    2015-01-01

    It is widely recognized that carbonic anhydrase (CA) participates in silicate weathering and carbonate formation. Nevertheless, it is still not known if the magnitude of the effect produced by CA on surface rock evolution changes or not. In this work, CA gene expression from Bacillus mucilaginosus and the effects of recombination protein on wollastonite dissolution and carbonate formation under different conditions are explored. Real-time fluorescent quantitative PCR was used to explore the correlation between CA gene expression and sufficiency or deficiency in calcium and CO2 concentration. The results show that the expression of CA genes is negatively correlated with both CO2 concentration and ease of obtaining soluble calcium. A pure form of the protein of interest (CA) is obtained by cloning, heterologous expression, and purification. The results from tests of the recombination protein on wollastonite dissolution and carbonate formation at different levels of CO2 concentration show that the magnitudes of the effects of CA and CO2 concentration are negatively correlated. These results suggest that the effects of microbial CA in relation to silicate weathering and carbonate formation may have increased importance at the modern atmospheric CO2 concentration compared to 3 billion years ago.

  9. Salt geometry influence on present-day stress orientations in the Nile Delta: Insights from numerical modeling

    NASA Astrophysics Data System (ADS)

    Eckert, Andreas; Zhang, Weicheng

    2016-02-01

    The offshore Nile Delta displays sharply contrasting orientations of the maximum horizontal stress, SH, in regions above Messinian evaporites (suprasalt) and regions below Messinian evaporites (subsalt). Published stress orientation data predominantly show margin-normal suprasalt SH orientations but a margin-parallel subsalt SH orientation. While these data sets provide the first major evidence that evaporite sequences can act as mechanical detachment horizons, the cause for the stress orientation contrast remains unclear. In this study, 3D finite element analysis is used to investigate the causes for stress re-orientation based on two different hypotheses. The modeling study evaluates the influence of different likely salt geometries and whether stress reorientations are the result of basal drag forces induced by gravitational gliding or whether they represent localized variations due to mechanical property contrasts. The modeling results show that when salt is present as a continuous layer, gravitational gliding occurs and basal drag forces induced in the suprasalt layers result in the margin-normal principal stress becoming the maximum horizontal stress. With the margin-normal stress increase being confined to the suprasalt layers, the salt acts as a mechanical detachment horizon, resulting in different SH orientations in the suprasalt compared to the subsalt layers. When salt is present as isolated bodies localized stress variations occur due to the mechanical property contrasts imposed by the salt, also resulting in different SH orientations in the suprasalt compared to the subsalt layers. The modeling results provide additional quantitative evidence to confirm the role of evaporite sequences as mechanical detachment horizons.

  10. Lessons Learned and Present Day Challenges of Addressing 20th Century Radiation Legacies of Russia and the United States

    SciTech Connect

    KRISTOFZSKI, J.G.

    2000-10-26

    The decommissioning of nuclear submarines, disposal of highly-enriched uranium and weapons-grade plutonium, and processing of high-level radioactive wastes represent the most challenging issues facing the cleanup of 20th century radiation legacy wastes and facilities. The US and Russia are the two primary countries dealing with these challenges, because most of the world's fissile inventory is being processed and stored at multiple industrial sites and nuclear weapons production facilities in these countries.

  11. Present-day challenges and future solutions in postoperative pain management: results from PainForum 2014.

    PubMed

    Kuusniemi, Kristiina; Pöyhiä, Reino

    2016-01-01

    This paper is a summary of presentations on postoperative pain control by the authors at the 2014 PainForum meeting in People's Republic of China. Postoperative pain is often untreated or undertreated and may lead to subsequent chronic pain syndromes. As more procedures migrate to the outpatient setting, postoperative pain control will become increasingly more challenging. Evidence-based guidelines for postoperative pain control recommend pain assessment using validated tools on a consistent basis. In this regard, consistency may be more important than the specific tool selected. Many hospitals have introduced a multidisciplinary acute pain service (APS), which has been associated with improved patient satisfaction and fewer adverse events. Patient education is an important component of postoperative pain control, which may be most effective when clinicians chose a multimodal approach, such as paracetamol (acetaminophen) and opioids. Opioids are a mainstay of postoperative pain control but require careful monitoring and management of side effects, such as nausea, vomiting, dizziness, and somnolence. Opioids may be administered using patient-controlled analgesia systems. Protocols for postoperative pain control can be very helpful to establish benchmarks for pain management and assure that clinicians adhere to evidence-based standards. The future of postoperative pain control around the world will likely involve more and better established APSs and greater communication between patients and clinicians about postoperative pain. The changes necessary to implement and move forward with APSs is not a single step but rather one of continuous improvement and ongoing change. PMID:26893579

  12. Present-day kinematics of the eastern Tibetan Plateau and Sichuan Basin: Implications for lower crustal rheology

    NASA Astrophysics Data System (ADS)

    Rui, X.; Stamps, D. S.

    2016-05-01

    The Sichuan Province comprises the cratonic Sichuan Basin and the eastern Tibetan Plateau separated by the recently activated Longmen Shan fault zone, thus providing a natural laboratory to study interseismic and postseismic processes. In this work we compute a new regional geodetic velocity solution from most of the continuous Global Navigation Satellite Systems (GNSS)/GPS data available in the Sichuan Province that we assess for transient postseismic deformation. For 11 continuous sites in close proximity to the Wenchuan 2008 event epicenter that were operational during the Wenchuan event we find an average short-term relaxation time of 11 days with maximum amplitude of 6.6 mm for the postseismic transient and no resolvable long-term transient. Using tests for block rigidity guided by previous kinematic studies we elucidate a longer-term transient in GNSS/GPS observations collected after the Wenchuan event that spans an extensive region of the eastern Tibetan Plateau. We correct for transients, produce an updated secular velocity field, and revise the kinematics of the region using elastic block modeling. Our results indicate that predicted slip rates are in good agreement with both geological and GNSS/GPS velocity profile-derived results, and we resolve two independent blocks with the expanded GNSS/GPS data set. Our constraints on the spatial extent of long-term postseismic deformation support models of ductile lower crust in the eastern margin of the Tibetan Plateau.

  13. The anthropogenic nature of present-day low energy rivers in western France and implications for current restoration projects

    NASA Astrophysics Data System (ADS)

    Lespez, L.; Viel, V.; Rollet, A. J.; Delahaye, D.

    2015-12-01

    As in other European countries, western France has seen an increase in river restoration projects. In this paper, we examine the restoration goals, methods and objectives with respect to the long-term trajectory and understanding of the contemporary dynamics of the small low energy rivers typical of the lowlands of Western Europe. The exhaustive geomorphological, paleoenvironmental and historical research conducted in the Seulles river basin (Normandy) provides very accurate documentation of the nature and place of the different legacies in the fluvial systems we have inherited. The sedimentation rate in the Seulles valley bottom has multiplied by a factor of 20 since the end of the Bronze Age and has generated dramatic changes in fluvial forms. Hydraulic control of the rivers and valley bottoms drainage throughout the last millennium has channelized rivers within these deposits. The single meandering channel which characterizes this river today is the legacy of the delayed and complex effects of long term exploitation of the river basin and the fluvial system. Bring to light that the "naturalness" of the restored rivers might be questioned. Our research emphasizes the gap between the poor knowledge of the functioning of these rivers and the concrete objectives of the restoration works undertaken, including dam and weir removal. Account of the long-term history of fluvial systems is required, not only to produce a pedagogic history of the "river degradation" but more fundamentally (i) to situate the current functioning of the fluvial system in a trajectory to try to identify thresholds and anticipate the potential turning points in a context of climate and land use change, (ii) to understand the role of morphosedimentary legacies on the current dynamics, (iii) to open the discussion on reference functioning or expected states and (iv) to open discussion on the sustainability of ecological restoration. To conclude, we point out the necessity to take into account the hybrid nature of low energy rivers in rural environments and to develop specific evaluation protocols which would include both biophysical processes and usual human activities which could be a way to share the evaluation and overcome conflicts between socioeconomic needs and environmental issues.

  14. Evidence and ideology as a rationale for light-therapy in Russia: from the Soviet Union to the present day

    PubMed Central

    Kühlbrandt, Charlotte; McKee, Martin

    2013-01-01

    Light therapy is still used to treat a number of common diseases in Russia. The practice is firmly anchored in history: Soviet clinical practice was divorced from the emerging field of evidence-based medicine. Medical researchers were cut off from international medical research and scientific literature, with much Soviet scientific activity based on a particular socialist ideology. In this study, the use of light therapy serves as a case study to explore tensions between international evidence-based medicine and practices developed in isolation under the Soviet Union, the legacy of which is to the detriment of many patients today. We used four different search methods to uncover scientific and grey literature, both historical and contemporary. We assessed the changing frequency of publications over time and contrasted the volume of literature on light therapy with more orthodox treatments such as statins and painkillers. Our search found an increasing number and comparatively large body of scientific publications on light therapy in the Russian language, and many publications emanating from prestigious Russian institutions. Combined with our analysis of the historical literature and our appraisal of 22 full text articles, this leads us to suggest that light therapy entered mainstream Soviet medical practice before the Stalinist period and still occupies an important position in contemporary Russian clinical practice. We propose that this outdated treatment survives in Russia in part due to the political, economic and social forces that helped to popularize it during Soviet times, and by the seeming justification offered by poorly executed studies. PMID:24040492

  15. Cerebrovascular diseases at the C. Mondino National Institute of Neurology: from Ottorino Rossi to the present day

    PubMed Central

    Micieli, Giuseppe; Martignoni, Emilia; Sandrini, Giorgio; Bono, Giorgio; Nappi, Giuseppe

    Summary This paper traces the development of research and healthcare models in the field of cerebrovascular disorders at the C. Mondino National Institute of Neurology in Pavia, Italy. It starts with a description of the original experiences of Ottorino Rossi and his thesis on atherosclerosis which date back to the beginning of the last century; it then illustrates the connections between his seminal essay and the future directions followed by research in this institute, through to the development of one of the first stroke units in Italy. In this context, we examine a large range of scientific approaches, many related to cerebrovascular diseases (such as headaches) and autonomic disorders, and some of their biological and physiological markers. The originality of an approach also based on tools of advanced technology, including information technology, is emphasised, as is the importance of passion and perseverance in the pursuit of extraordinary results in what is an extremely complex and difficult field. PMID:21729590

  16. Ductile deformation, boudinage and low angle normal faults. An overview of the structural variability at present-day rifted margins

    NASA Astrophysics Data System (ADS)

    Clerc, Camille; Jolivet, Laurent; Ringenbach, Jean-Claude; Ballard, Jean-François

    2016-04-01

    High quality industrial seismic profiles acquired along most of the world's passive margins present stunningly increased resolution that leads to unravel an unexpected variety of structures. An important benefit of the increased resolution of recent seismic profiles is that they provide an unprecedented access to the processes occurring in the middle and lower continental crust. We present a series of so far unreleased profiles that allow the identification of various rift-related geological processes such as crustal boudinage, ductile shear and low angle detachment faulting. The lower crust in passive margins appears much more intensely deformed than usually represented. At the foot of both magma-rich and magma-poor margins, we observe clear indications of ductile deformation of the deep continental crust along large-scale shallow dipping shear zones. These shear zones generally show a top-to-the-continent sense of shear consistent with the activity of overlying continentward dipping normal faults observed in the upper crust. This pattern is responsible for a migration of the deformation and associated sedimentation and/or volcanic activity toward the ocean. In some cases, low angle shear zones define an anastomosed pattern that delineates boudin-like structures. The interboudins areas seem to localize the maximum of deformation. The lower crust is intensely boudinaged and the geometry of those boudins seems to control the position and dip of upper crustal normal faults. We present some of the most striking examples (Uruguay, West Africa, Barents sea…) and discuss their implications for the time-temperature-subsidence history of the margins.

  17. Phylogenetic diversity as a window into the evolutionary and biogeographic histories of present-day richness gradients for mammals.

    PubMed

    Davies, T Jonathan; Buckley, Lauren B

    2011-08-27

    Phylogenetic diversity (PD) captures the shared ancestry of species, and is increasingly being recognized as a valuable conservation currency. Regionally, PD frequently covaries closely with species richness; however, variation in speciation and extinction rates and/or the biogeographic history of lineages can result in significant deviation. Locally, these differences may be pronounced. Rapid recent speciation or high temporal turnover of lineages can result in low PD but high richness. In contrast, rare dispersal events, for example, between biomes, can elevate PD but have only small impact on richness. To date, environmental predictors of species richness have been well studied but global models explaining variation in PD are lacking. Here, we contrast the global distribution of PD versus species richness for terrestrial mammals. We show that an environmental model of lineage diversification can predict well the discrepancy in the distribution of these two variables in some places, for example, South America and Africa but not others, such as Southeast Asia. When we have information on multiple diversity indices, conservation efforts directed towards maximizing one currency or another (e.g. species richness versus PD) should also consider the underlying processes that have shaped their distributions. PMID:21768156

  18. A Lagrangian analysis of the present-day sources of moisture for major ice-core sites

    NASA Astrophysics Data System (ADS)

    Drumond, Anita; Taboada, Erica; Nieto, Raquel; Gimeno, Luis; Vicente-Serrano, Sergio M.; López-Moreno, Juan Ignacio

    2016-07-01

    A Lagrangian approach was used to identify the moisture sources for 14 ice-core sites located worldwide for the period of 1980-2012. The sites were classified into three domains: Arctic, Central (Andes, Alps, and Kilimanjaro), and Antarctic. The approach was used to compute budgets of evaporation minus precipitation by calculating changes in the specific humidity along 10-day backward trajectories. The results indicate that the oceanic regions around the subtropical high-pressure centres provide most of moisture, and their contribution varies throughout the year following the annual cycles of the centres. For the Arctic Domain, the sources lie in the subtropical North Atlantic and Pacific. The subtropical South Atlantic, Indian, and Pacific oceans provide moisture for the Antarctic Domain. The sources for South America are the Atlantic and South Pacific, for Europe the sources are in the Mediterranean and the North Atlantic, and for Asia the sources are the Indian Ocean and the Arabian Sea.

  19. Utilizing DNA analysis to combat the world wide plague of present day slavery – trafficking in persons

    PubMed Central

    Palmbach, Timothy; Blom, Jeffrey; Hoynes, Emily; Primorac, Dragan; Gaboury, Mario

    2014-01-01

    A study was conducted to determine if modern forensic DNA typing methods can be properly employed throughout the world with a final goal of increasing arrests, prosecutions, and convictions of perpetrators of modern day trafficking in persons while concurrently reducing the burden of victim testimony in legal proceedings. Without interruption of investigations, collection of samples containing DNA was conducted in a variety of settings. Evidentiary samples were analyzed on the ANDE Rapid DNA system. Many of the collected swabs yielded informative short tandem repeat profiles with Rapid DNA technology. PMID:24577820

  20. The present-day flux of large meteoroids on the lunar surface—A synthesis of models and observational techniques

    NASA Astrophysics Data System (ADS)

    Oberst, J.; Christou, A.; Suggs, R.; Moser, D.; Daubar, I. J.; McEwen, A. S.; Burchell, M.; Kawamura, T.; Hiesinger, H.; Wünnemann, K.; Wagner, R.; Robinson, M. S.

    2012-12-01

    Monitoring the lunar surface for impacts is a highly rewarding approach to study small asteroids and large meteoroids encountering the Earth-Moon System. The various effects of meteoroids impacting the Moon are described and results from different detection and study techniques are compared. While the traditional statistics of impact craters allow us to determine the cumulative meteoroid flux on the lunar surface, the recent successful identification of fresh craters in orbital imagery has the potential to directly measure the cratering rate of today. Time-resolved recordings, e.g., seismic data of impacts and impact flash detections clearly demonstrate variations of the impact flux during the lunar day. From the temporal/spatial distribution of impact events, constraints can be obtained on the meteoroid approach trajectories and velocities. The current monitoring allows us to identify temporal clustering of impacts and to study the different meteoroid showers encountering the Earth-Moon system. Though observational biases and deficiencies in our knowledge of the scaling laws are severe, there appears to be an order-of-magnitude agreement in the observed flux within the error limits. Selenographic asymmetries in the impact flux (e.g., for equatorial vs. polar areas) have been predicted. An excess of impacts on the lunar leading hemisphere can be demonstrated in current data. We expect that future missions will allow simultaneous detections of seismic events and impact flashes. The known locations and times of the flashes will allow us to constrain the seismic solutions. While the numbers of flash detections are still limited, coordinated world-wide observations hold great potential for exploiting this observation technique. The potential for identification of fresh craters in high-resolution orbital image data has just barely been tapped, but should improve significantly with the LRO extended mission.

  1. Present-Day Hospital Readmissions after Left Ventricular Assist Device Implantation: A Large Single-Center Study

    PubMed Central

    Hernandez, Ruben E.; Singh, Steve K.; Hoang, Dale T.; Ali, Syed W.; Elayda, MacArthur A.; Mallidi, Hari R.; Frazier, O.H.

    2015-01-01

    Left ventricular assist device (LVAD) therapy improves survival, hemodynamic status, and end-organ perfusion in patients with refractory advanced heart failure. Hospital readmission is an important measure of the intensity of LVAD support care. We analyzed readmissions of 148 patients (mean age, 53.6 ± 12.7 yr; 83% male) who received a HeartMate II LVAD from April 2008 through June 2012. The patients had severe heart failure; 60.1% were in Interagency Registry for Mechanically Assisted Circulatory Support class 1 or 2. All patients were observed for at least 12 months, and readmissions were classified as planned or unplanned. Descriptive and multivariate regression analyses were used to identify predictors of unplanned readmission. Twenty-seven patients (18.2%) had no readmissions or 69 planned readmissions, and 121 patients (81.8%) had 460 unplanned readmissions. The LVAD-related readmissions were for bleeding, thrombosis, and anticoagulation (n=103; 49.1%), pump-related infections (n=60; 28.6%), and neurologic events (n=28; 13.3%). The readmission rate was 2.1 per patient-year. Unplanned readmissions were for comorbidities and underlying cardiac disease (54.3%) or LVAD-related causes (45.7%). In the unplanned-readmission rate, there was no significant difference between bridge-to-transplantation and destination-therapy patients. Unplanned readmissions were associated with diabetes mellitus (odds ratio [OR]=3.3; P=0.04) and with shorter mileage from residence to hospital (OR=0.998; P=0.046). Unplanned admissions for LVAD-related sequelae and ongoing comorbidities were common. Diabetes mellitus and shorter distance from residence to hospital were significant predictors of readmission. We project that improved management of comorbidities and of anticoagulation therapy will reduce unplanned readmissions of LVAD patients in the future. PMID:26504434

  2. [The model of state health policy and the system of medical assistance adopted in present-day Brazil].

    PubMed

    Queiroz, M de S; Vianna, A L

    1992-04-01

    A contribution to the analysis of the health reform presently occurring in Brazil is presented. The need to consolidate the theoretical background which supports the advances already achieved in order to understand recent events in the area is stressed. In this regard, the health reform is understood as a question transcending the mere administrative and managerial aspect of the health system, since it necessarily involves a redefinition of the concepts of health, disease and the medical practice adopted by the dominant mechanistic paradigm of medicine. The recent events which delineate the health system in Brazil are analysed and criticised in the light of this concern. PMID:1307428

  3. Present-day Galactic Evolution: Low-metallicity, Warm, Ionized Gas Inflow Associated with High-velocity Cloud Complex A

    NASA Astrophysics Data System (ADS)

    Barger, K. A.; Haffner, L. M.; Wakker, B. P.; Hill, Alex. S.; Madsen, G. J.; Duncan, A. K.

    2012-12-01

    The high-velocity cloud Complex A is a probe of the physical conditions in the Galactic halo. The kinematics, morphology, distance, and metallicity of Complex A indicate that it represents new material that is accreting onto the Galaxy. We present Wisconsin Hα Mapper kinematically resolved observations of Complex A over the velocity range of -250 to -50 km s-1 in the local standard of rest reference frame. These observations include the first full Hα intensity map of Complex A across (\\mathit {l, b}) = (124{^\\circ }, 18{^\\circ }) to (171°, 53°) and deep targeted observations in Hα, [S II] λ6716, [N II] λ6584, and [O I] λ6300 toward regions with high H I column densities, background quasars, and stars. The Hα data imply that the masses of neutral and ionized material in the cloud are similar, both being greater than 106 M ⊙. We find that the Bland-Hawthorn & Maloney model for the intensity of the ionizing radiation near the Milky Way is consistent with the known distance of the high-latitude part of Complex A and an assumed cloud geometry that puts the lower-latitude parts of the cloud at a distance of 7-8 kpc. This compatibility implies a 5% ionizing photon escape fraction from the Galactic disk. We also provide the nitrogen and sulfur upper abundance solutions for a series of temperatures, metallicities, and cloud configurations for purely photoionized gas; these solutions are consistent with the sub-solar abundances found by previous studies, especially for temperatures above 104 K or for gas with a high fraction of singly ionized nitrogen and sulfur.

  4. Geometry of structures within crystalline bedrock constrained in 3D and their relevance for present day water infiltration.

    NASA Astrophysics Data System (ADS)

    Schneeberger, Raphael; de la Varga, Miguel; Florian Wellmann, J.; Kober, Florian; Berger, Alfons; Herwegh, Marco

    2016-04-01

    Fluid circulation in crystalline rocks is of key importance when exploring crystalline basement in light of, for example, deep-seated geothermal energy projects or selection of sites for nuclear waste repositories. Due to their enhanced permeability, fluid circulation within crystalline bedrock is mainly controlled by fault zones, which may originate from ductile mylonites but show a strong brittle overprint. In order to better constrain 3D flow paths, a well-founded knowledge on the 3D nature of the fault zone pattern is indispensable. We attempt to constrain the geometry of a complex 3D fault zone pattern in a case study of the Grimsel Test Site (GTS, central Switzerland). The constraints are based on mapping of both the surface as well as the GTS underground tunnel system, offering a unique opportunity to test the 3D model and associated uncertainties. We investigate the effect of increasing geoinformation on the quality and accuracy of the 3D model by using: (i) remote sensing surface data only, (ii) field surface mapping in combination with (i), and (iii) underground data combined with (i) and (ii). This approach allows for defining different steps in 3D geological modelling of a specific area, including a measure of the remaining uncertainty after each step. We obtain a best-estimate model by fitting results between surface and underground data by using a combination of field data and orientation obtained by Delaunay triangulation. We incorporate novel approaches to uncertainty analysis of fault orientations and investigate different fault planes showing the possible variation range of the structures investigated.

  5. Present-Day Kinematics of the Dead Sea Transform and Internal Deformation within the Sinai and Arabian Plates

    NASA Astrophysics Data System (ADS)

    Gomez, F. G.; Yassminh, R.; Cochran, W. J.; Reilinger, R. E.; Barazangi, M.

    2015-12-01

    An updated GPS velocity field along the Dead Sea Fault (DSF) provides a basis for assessing off-transform strain within the Sinai and Arabian plates along entire length of this left-lateral, continental transform. As one of the main tectonic elements in the eastern Mediterranean region, an improved kinematic view of the DSF elucidates the broader understanding of the regional tectonic framework, as well as contributes to refining the earthquake hazard assessment. Reconciling short-term (geodetic) measurements of crustal strain with neotectonic data on fault movements can yield insight into the mechanical and rheological properties of crustal deformation associated with transform tectonics. In addition to regional continuous GPS stations, this study assembles results from campaign GPS networks in Syria, Lebanon, and Jordan spanning more than a decade. 1-sigma uncertainties on velocities range from less than 0.4 mm/yr (continuous stations and older GPS survey sites) to about 1.0 mm/yr (newer survey sites). Analyses using elastic block models suggest slip rates of 4.0 - 5.0 mm/yr along the southern and central DSF and slip rates of 2.0 - 3.0 mm/yr along the northern DSF, and fault locking depths also vary along strike of the transform. Furthermore, the spatial distribution of GPS observations permits analyzing residual strains within the adjacent plates, after plate boundary strain is removed. A key observation is horizontal stretching within the Sinai plate, which may be related to pull by the subducted slab of the Sinai plate. Within the Arabian plate, areas of horizontal stretching generally correlate with locations of Quaternary volcanism.

  6. PRESENT-DAY DESCENDANTS OF z = 3 Ly{alpha}-EMITTING GALAXIES IN THE MILLENNIUM-II HALO MERGER TREES

    SciTech Connect

    Walker-Soler, Jean P.; Gawiser, Eric; Bond, Nicholas A.; Padilla, Nelson; Francke, Harold

    2012-06-20

    Using the Millennium-II Simulation dark matter sub-halo merger histories, we created mock catalogs of Ly{alpha}-emitting (LAE) galaxies at z = 3.1 to study the properties of their descendants. Several models were created by selecting the sub-halos to match the number density and typical dark matter mass determined from observations of these galaxies. We used mass-based and age-based selection criteria to study their effects on descendant populations at z {approx_equal} 2, 1, and 0. For the models that best represent LAEs at z = 3.1, the z = 0 descendants have a median dark matter halo mass of 10{sup 12.7} M{sub Sun }, with a wide scatter in masses (50% between 10{sup 11.8} and 10{sup 13.7} M{sub Sun }). Our study differentiated between central and satellite sub-halos and found that {approx}55% of z = 0 descendants are central sub-halos with M{sub Median} {approx} 10{sup 12}. This confirms that central z = 0 descendants of z = 3.1 LAEs have halo masses typical of L*-type galaxies. The satellite sub-halos reside in group/cluster environments with dark matter masses around 10{sup 14} M{sub Sun }. The median descendant mass is robust to various methods of age determination, but it could vary by a factor of five due to current observational uncertainties in the clustering of LAEs used to determine their typical z = 3.1 dark matter mass.

  7. Studies of volatiles and organic materials in early terrestrial and present-day outer solar system environments

    NASA Technical Reports Server (NTRS)

    Sagan, Carl; Thompson, W. Reid; Chyba, Christopher F.; Khare, B. N.

    1991-01-01

    A review and partial summary of projects within several areas of research generally involving the origin, distribution, chemistry, and spectral/dielectric properties of volatiles and organic materials in the outer solar system and early terrestrial environments are presented. The major topics covered include: (1) impact delivery of volatiles and organic compounds to the early terrestrial planets; (2) optical constants measurements; (3) spectral classification, chemical processes, and distribution of materials; and (4) radar properties of ice, hydrocarbons, and organic heteropolymers.

  8. How fast is Arctic climate really changing? An insight from recent past, present day and near future coupled model simulations

    NASA Astrophysics Data System (ADS)

    Koenigk, Torben; Brodeau, Laurent

    2016-04-01

    Three quasi-equilibrium simulations using constant greenhouse gas forcing corresponding to years 2000, 2015 and 2030 have been performed with the global coupled model EC-Earth in order to analyze recent past and possible near future changes in the Arctic climate. The model simulations indicate an accelerated warming and ice extent reduction in the Arctic in near future conditions compared to the recent past. Both Arctic warming and sea ice reduction are closely linked to the increase of ocean heat transport into the Arctic, particularly through the Barents Sea Opening. Decadal variations of Arctic sea ice extent and ice volume are of the same order of magnitude as the observed ice extent reductions in the last 30 years and are dominated by the variability of the ocean heat transports through the Barents Sea Opening and the Bering Strait. Despite a general warming of mid and high northern latitudes, a substantial cooling is found in the subpolar gyre of the North Atlantic in the near future simulation. This cooling is related to a strong reduction in the AMOC, which is mainly caused by reduced deep water formation in the Labrador Sea. The observed trend towards a more negative phase of the North Atlantic Oscillation (NAO) and the observed linkage between autumn Arctic ice variations and NAO are reproduced in our model simulations for selected 30-year periods but are not robust over longer time periods. This indicates that the observed linkages between ice and NAO might not be robust in reality either, and that the observational time period is still too short to reliably separate the trend from the natural variability.

  9. ABSORPTION-LINE PROBES OF THE PREVALENCE AND PROPERTIES OF OUTFLOWS IN PRESENT-DAY STAR-FORMING GALAXIES

    SciTech Connect

    Chen Yanmei; Kauffmann, Guinevere; Wang Jing; Tremonti, Christy A.; Heckman, Timothy M.; Weiner, Benjamin J.; Brinchmann, Jarle

    2010-08-15

    We analyze star-forming galaxies drawn from SDSS DR7 to show how the interstellar medium (ISM) Na I {lambda}{lambda}5890, 5896 (Na D) absorption lines depend on galaxy physical properties, and to look for evidence of galactic winds. We combine the spectra of galaxies with similar geometry/physical parameters to create composite spectra with signal-to-noise {approx}300. The stellar continuum is modeled using stellar population synthesis models, and the continuum-normalized spectrum is fit with two Na I absorption components. We find that (1) ISM Na D absorption lines with equivalent widths EW > 0.8 A are only prevalent in disk galaxies with specific properties-large extinction (A{sub V} ), high star formation rates (SFR), high SFR per unit area ({Sigma}{sub SFR}), or high stellar mass (M{sub *}); (2) the ISM Na D absorption lines can be separated into two components: a quiescent disk-like component at the galaxy systemic velocity and an outflow component; (3) the disk-like component is much stronger in the edge-on systems, and the outflow component covers a wide angle but is stronger within 60{sup 0} of the disk rotation axis; (4) the EW and covering factor of the disk component correlate strongly with dust attenuation, highlighting the importance that dust shielding may play in the survival of Na I; (5) the EW of the outflow component depends primarily on {Sigma}{sub SFR} and secondarily on A{sub V} ; and (6) the outflow velocity varies from {approx}120 to 160 km s{sup -1} but shows little hint of a correlation with galaxy physical properties over the modest dynamic range that our sample probes (1.2 dex in log {Sigma}{sub SFR} and 1 dex in log M{sub *}).

  10. Electrocardiograph abnormalities revealed during laparoscopy

    PubMed Central

    Nijjer, Sukhjinder; Dubrey, Simon William

    2010-01-01

    This brief case presents a well patient in whom an electrocardiograph abnormality consistent with an accessory pathway was found during a routine procedure. We present the electrocardiographs, explain the underlying condition, and consider why the abnormality was revealed in this manner. PMID:22419949

  11. Ischemic Colitis Revealing Polyarteritis Nodosa

    PubMed Central

    Hamzaoui, Amira; Litaiem, Noureddine; Smiti Khanfir, M.; Ayadi, Sofiene; Nfoussi, Haifa; Houman, M. H.

    2013-01-01

    Ischemic colitis is one of the most common intestinal ischemic injuries. It results from impaired perfusion of blood to the bowel and is rarely caused by vasculitis. We report a case of ischemic colitis revealing polyarteritis nodosa (PAN) in a 55-year-old man. Histological examination of the resected colon led to the diagnosis of PAN. PMID:24382967

  12. Urticarial vasculitis reveals unsuspected thyroiditis.

    PubMed

    Ferreira, Olga; Mota, Alberto; Baudrier, Teresa; Azevedo, Filomena

    2012-01-01

    A 38-year-old woman presented with erythematous, violaceous plaques with a serpiginous and unusual appearance located on the left shoulder, left thigh, and right buttock, evolving for 5 days, which eventually became generalized. A skin biopsy revealed leukocytoclastic vasculitis and a diagnosis of urticarial vasculitis was made. The complete blood count, biochemistry, complement levels, and other immunological test results were unremarkable. However, antithyroid antibody titers were increased. Despite having normal thyroid function tests and an absence of specific symptoms, the patient underwent a thyroid ultrasound, which revealed features of thyroiditis, and was subsequently referred to an endocrinologist. Several diseases can be associated with urticarial vasculitis, namely infections and autoimmune connective-tissue disorders such as systemic lupus erythematosus and Sjögren syndrome. Thyroiditis is an uncommon association. PMID:23000939

  13. Plan competitions reveal entrepreneurial talent

    SciTech Connect

    Madison, Alison L.

    2011-05-15

    Monthly economic diversity column for Tri-City Herald business section. Excerpt below: There’s something to be said for gaining valuable real-world experience in a structured, nurturing environment. Take for instance learning to scuba dive in the comfort of my resort pool rather than immediately hanging out with sharks while I figure out little things like oxygen tanks and avoiding underwater panic attacks. Likewise, graduate students are getting some excellent, supportive real-world training through university business plan competitions. These competitions are places where smart minds, new technologies, months of preparation and coaching, and some healthy pre-presentation jitters collide to reveal not only solid new business ideas, but also some promising entrepreneurial talent. In fact, professionals from around our region descend upon college campuses every spring to judge these events, which help to bridge the gap between academics and the real technology and business-driven economy.

  14. Revealing ontological commitments by magic.

    PubMed

    Griffiths, Thomas L

    2015-03-01

    Considering the appeal of different magical transformations exposes some systematic asymmetries. For example, it is more interesting to transform a vase into a rose than a rose into a vase. An experiment in which people judged how interesting they found different magic tricks showed that these asymmetries reflect the direction a transformation moves in an ontological hierarchy: transformations in the direction of animacy and intelligence are favored over the opposite. A second and third experiment demonstrated that judgments of the plausibility of machines that perform the same transformations do not show the same asymmetries, but judgments of the interestingness of such machines do. A formal argument relates this sense of interestingness to evidence for an alternative to our current physical theory, with magic tricks being a particularly pure source of such evidence. These results suggest that people's intuitions about magic tricks can reveal the ontological commitments that underlie human cognition. PMID:25490128

  15. CMB source apportionment during REVEAL

    SciTech Connect

    Lowenthal, D.H.; Gertler, A.W.; Wittorff, D.; Sakiyama, S.

    1997-01-01

    Source contributions to PM{sub 2.5} aerosol measured at Chilliwack and Pitt Meadows in the Lower Fraser Valley, B.C., Canada, during the REVEAL study, were estimated using chemical mass balance (CMB) receptor modeling. ON average, motor vehicles accounted for 34 and 43% of PM{sub 2.5} at Chilliwack and Pitt Meadows, respectively. Secondary sulfate and secondary nitrate were the next most significant PM{sub 2.5} components, accounting for 25 and 27%, respectively, at Chilliwack, and 27 and 12%, respectively, at Pitt Meadows. Geological material accounted for 3 and 5% of PM{sub 2.5} at Chilliwack and Pitt Meadows, respectively. A significant contribution of wood smoke was estimated for both sites: 8% at Chilliwack and 9% at Pitt Meadows.

  16. Archimedes: Accelerator Reveals Ancient Text

    SciTech Connect

    Bergmann, Uwe

    2004-02-24

    Archimedes (287-212 BC), who is famous for shouting 'Eureka' (I found it) is considered one of the most brilliant thinkers of all times. The 10th-century parchment document known as the 'Archimedes Palimpsest' is the unique source for two of the great Greek's treatises. Some of the writings, hidden under gold forgeries, have recently been revealed at the Stanford Synchrotron Radiation Laboratory at SLAC. An intense x-ray beam produced in a particle accelerator causes the iron in original ink, which has been partly erased and covered, to send out a fluorescence glow. A detector records the signal and a digital image showing the ancient writings is produced. Please join us in this fascinating journey of a 1,000-year-old parchment from its origin in the Mediterranean city of Constantinople to a particle accelerator in Menlo Park.

  17. Erosion and what it Reveals

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 20 November 2003

    This image is located near the boundary between Syrtis Major and Isidis Planitia. The top of the image shows rough material that has eroded away from the lower portion of the image, revealing an underlying surface that has many small craters. It also reveals an ancient flow lobe that is barely discernable, crossing the southern part of the image (this flow lobe is much easier to see as a smooth region in the context image).

    Image information: VIS instrument. Latitude 16.4, Longitude 77.9 East (282.1 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  18. Dunes reveal Titan's recent history

    NASA Astrophysics Data System (ADS)

    Savage, Christopher J.; Radebaugh, Jani

    2010-04-01

    Large fields of linear dunes are abundant on Titan, covering nearly 20% of the surface. They are among the youngest features and represent interactions between near-surface winds and sediment. This interaction may vary from area to area creating unique populations of eolian features identified by dune field parameters such as crest-to-crest spacing, dune width and orientation. These parameters respond to changes in near-surface conditions over periods of time ranging from minutes to many thousands of years depending on dune size and the duration of the changes. While pattern analysis of dune field parameters on Earth and, in this study, Titan reveals much about current climatic conditions, such as wind regimes and wetter vs. drier areas, many inferences about past conditions can also be made. Initial pattern analysis of linear dunes on Titan reveals a single population of linear dunes representing a large percentage of all observed dunes. This single population is the result of two leading possibilities: Either there has been only one long period of dune building, leading to very old cores that have been built upon over long periods of time, perhaps punctuated with few or many intervals of non-deposition; or the current conditions of dune building have persisted long enough to completely erase any evidence of previous conditions. We have not yet worked through all the input parameters to adjust Earth's time scales to Titan's, and thus it is not yet possible to give a precise age for Titan's dunes. However, if these large linear dunes are similar to Earth's large linear dunes, they may represent at least several thousand years of dune building.

  19. APEX reveals glowing stellar nurseries

    NASA Astrophysics Data System (ADS)

    2008-11-01

    Illustrating the power of submillimetre-wavelength astronomy, an APEX image reveals how an expanding bubble of ionised gas about ten light-years across is causing the surrounding material to collapse into dense clumps that are the birthplaces of new stars. Submillimetre light is the key to revealing some of the coldest material in the Universe, such as these cold, dense clouds. Glowing Stellar Nurseries ESO PR Photo 40/08 Glowing Stellar Nurseries The region, called RCW120, is about 4200 light years from Earth, towards the constellation of Scorpius. A hot, massive star in its centre is emitting huge amounts of ultraviolet radiation, which ionises the surrounding gas, stripping the electrons from hydrogen atoms and producing the characteristic red glow of so-called H-alpha emission. As this ionised region expands into space, the associated shock wave sweeps up a layer of the surrounding cold interstellar gas and cosmic dust. This layer becomes unstable and collapses under its own gravity into dense clumps, forming cold, dense clouds of hydrogen where new stars are born. However, as the clouds are still very cold, with temperatures of around -250˚ Celsius, their faint heat glow can only be seen at submillimetre wavelengths. Submillimetre light is therefore vital in studying the earliest stages of the birth and life of stars. The submillimetre-wavelength data were taken with the LABOCA camera on the 12-m Atacama Pathfinder Experiment (APEX) telescope, located on the 5000 m high plateau of Chajnantor in the Chilean Atacama desert. Thanks to LABOCA's high sensitivity, astronomers were able to detect clumps of cold gas four times fainter than previously possible. Since the brightness of the clumps is a measure of their mass, this also means that astronomers can now study the formation of less massive stars than they could before. The plateau of Chajnantor is also where ESO, together with international partners, is building a next generation submillimetre telescope, ALMA

  20. Hubble Images Reveal Jupiter's Auroras

    NASA Technical Reports Server (NTRS)

    1996-01-01

    These images, taken by the Hubble Space Telescope, reveal changes in Jupiter's auroral emissions and how small auroral spots just outside the emission rings are linked to the planet's volcanic moon, Io. The images represent the most sensitive and sharply-detailed views ever taken of Jovian auroras.

    The top panel pinpoints the effects of emissions from Io, which is about the size of Earth's moon. The black-and-white image on the left, taken in visible light, shows how Io and Jupiter are linked by an invisible electrical current of charged particles called a 'flux tube.' The particles - ejected from Io (the bright spot on Jupiter's right) by volcanic eruptions - flow along Jupiter's magnetic field lines, which thread through Io, to the planet's north and south magnetic poles. This image also shows the belts of clouds surrounding Jupiter as well as the Great Red Spot.

    The black-and-white image on the right, taken in ultraviolet light about 15 minutes later, shows Jupiter's auroral emissions at the north and south poles. Just outside these emissions are the auroral spots. Called 'footprints,' the spots are created when the particles in Io's 'flux tube' reach Jupiter's upper atmosphere and interact with hydrogen gas, making it fluoresce. In this image, Io is not observable because it is faint in the ultraviolet.

    The two ultraviolet images at the bottom of the picture show how the auroral emissions change in brightness and structure as Jupiter rotates. These false-color images also reveal how the magnetic field is offset from Jupiter's spin axis by 10 to 15 degrees. In the right image, the north auroral emission is rising over the left limb; the south auroral oval is beginning to set. The image on the left, obtained on a different date, shows a full view of the north aurora, with a strong emission inside the main auroral oval.

    The images were taken by the telescope's Wide Field and Planetary Camera 2 between May 1994 and September 1995.

    This image and

  1. Plant transcriptomes reveal hidden guests.

    PubMed

    Zhu, Jiao; Wang, Guirong; Pelosi, Paolo

    2016-06-01

    With the wide adoption of transcriptome sequencing an ever increasing amount of information is becoming available, together with spurious data originating from contamination. We show that sometimes errors and inaccuracy can turn beneficial, revealing insect and arthropod pests when analysing plant transcriptomes. We have found a large number of soluble olfactory proteins, odorant-binding proteins (OBPs) and chemosensory proteins (CSPs), in plant databases, likely due to contamination by guest insects. In fact, both classes of proteins are only expressed in insects, with few CSPs also present in other arthropods. In addition, we found many sequences of the Niemann-Pick (Npc2) family, proteins dedicated to cholesterol transport in vertebrates and hypothesised to be involved in chemical communication in insects, but absent in plants. In several cases we were able to trace down members of the three classes of proteins to the insect or arthopod species responsible for contamination. Our work suggests that genes found in plants and recognised as contaminants can be turned into useful information to investigate plant-insect relationships or to identify new sequences from insects species not yet investigated. PMID:27130825

  2. Revealing ionic motion molecular solids

    NASA Astrophysics Data System (ADS)

    Thurzo, I.; Zahn, D. R. T.

    2006-01-01

    Thin films of mixed valence semiconductor copper-tetracyano-quinodimethane (Cu-TCNQ) and small molecule tris(8-hydroxyquinolinato)aluminum (Alq3) were investigated by current-voltage (I-V) and admittance (C-V,G-V) techniques in single-layer configuration with different combinations of electrodes. The predicted hysteresis of I-V curves and nearly constant loss (NCL) could be observed for both materials. When cycling devices between negative and positive biases, slowly decaying ionic transient currents interfere with steady-state currents and point to unidirectional motions of the ionic species with subsequent redox reaction at one of the electrodes. Plotting the frequency f dependence of the equivalent parallel capacitance at zero bias as log10 C(0) versus log10(f), the dielectric behavior of Cu-TCNQ and Alq3 complies with the effective-medium model for NCL in ionic conductors [J. R. Macdonald J. Appl. Phys. 94, 558 (2003)]. It also holds for a similar plot of the equivalent parallel zero-bias conductance G(0). The nature of the revealed mobile ions is discussed with emphasis on their sources.

  3. Reveal for Salmonella test system.

    PubMed

    Bird, C B; Miller, R L; Miller, B M

    1999-01-01

    The Reveal for Salmonella (RSS) test system is a presumptive qualitative test that detects the presence of Salmonella organisms in foods within 21 h total testing time, allowing the user to release negative products 24 h earlier than when using other rapid test kits. Foods are enriched with a proprietary resuscitation medium called Revive and then selectively enriched with either Selenite Cystine or Rappaport-Vassiliadis selective media. The enriched culture is used to inoculate the RSS detection device, which initiates a lateral flow through a reagent zone containing anti-Salmonella antibodies conjugated to colloidal gold particles that capture antigens present in the culture. The antigen-antibody complex migrates farther and is captured by an additional anti-Salmonella antibody, causing the colloidal gold to precipitate and form a visual line, indicating a positive result. A procedural control line also will form regardless of the presence of Salmonella organisms to indicate the test is working properly. Existing AOAC Official Methods for Salmonella organisms require a 48 h enrichment before testing. Hence, a food product has to be held before release, adding extra cost to the company and the consumer. The RSS test system was evaluated by quantitative spiking studies. Although AOAC encourages inclusion of naturally contaminated foods, almost all microbiological AOAC validation studies have been performed with artificially contaminated foods for absolute control over the study. The RSS test system is designed to test many food types for Salmonella organisms and has a limit of detection of 5-10 colony-forming units (cfu)/25 g with a false-negative rate of < 1% and a false-positive rate of < 5.0%. It showed an 81% overall agreement with the traditional procedure of the U.S. Department of Agriculture's Food Safety Inspection Service. PMID:10367381

  4. Focus groups reveal consumer ambivalence.

    PubMed

    1983-01-01

    According to qualitative research, Salvadoreans are ambivalent about the use of contraceptives. Since complete responsibility for management of the CSM project was accepted by the Association Demografica Salvadorena (ADS), the agency which operates the contraceptive social marketing project in El Salvador, in November 1980, the need for decisions in such areas as product price increases, introduction of new condom brands, promotion of the vaginal foaming tablet, and assessment of product sales performance had arisen. The ICSMP funded market research, completed during 1983, was intended to provide the data on which such decisions by ADS could be based. The qualitative research involved 8 focus groups, comprised of men and women, aged 18-45, contraceptive users and nonusers, from the middle and lower socioeconomic strata of the city of San Salvador and other suburban areas. In each group a moderator led discussion of family planning and probed respondents for specific attitudes, knowledge, and behavior regarding the use of contraceptives. To assess attitudes at a more emotional level, moderators asked respondents to "draw" their ideas on certain issues. A marked discrepancy was revealed between respondents' intellectual responses to the issues raised in group discussion, as opposed to their feelings expressed in the drawings. Intellectually, participants responded very positively to family planning practice, but when they were asked to draw their perceptions, ambivalent feelings emerged. Drawings of both the user and the nonuser convey primarily negative aspects for either choice. The user is tense and moody toward her children; the nonuser loses her attractiveness and "dies." Figures also show drawings of some of the attitudes of single and married male participants. 1 drawing shows an incomplete and a complete circle, symbolizing a sterilized man (incomplete) and a nonsterilized man (complete). Another picture depicts a chained man who has lost his freedom

  5. SCN4B-Encoded Sodium Channel β4 Subunit in Congenital Long-QT Syndrome

    PubMed Central

    Medeiros-Domingo, Argelia; Kaku, Toshihiko; Tester, David J.; Iturralde-Torres, Pedro; Itty, Ajit; Ye, Bin; Valdivia, Carmen; Ueda, Kazuo; Canizales-Quinteros, Samuel; Tusié-Luna, Maria Teresa; Makielski, Jonathan C.; Ackerman, Michael J.

    2012-01-01

    Background Congenital long-QT syndrome (LQTS) is potentially lethal secondary to malignant ventricular arrhythmias and is caused predominantly by mutations in genes that encode cardiac ion channels. Nearly 25% of patients remain without a genetic diagnosis, and genes that encode cardiac channel regulatory proteins represent attractive candidates. Voltage-gated sodium channels have a pore-forming α-subunit associated with 1 or more auxiliary β-subunits. Four different β-subunits have been described. All are detectable in cardiac tissue, but none have yet been linked to any heritable arrhythmia syndrome. Methods and Results We present a case of a 21-month-old Mexican-mestizo female with intermittent 2:1 atrioventricular block and a corrected QT interval of 712 ms. Comprehensive open reading frame/splice mutational analysis of the 9 established LQTS-susceptibility genes proved negative, and complete mutational analysis of the 4 Navβ-subunits revealed a L179F (C535T) missense mutation in SCN4B that cosegregated properly throughout a 3-generation pedigree and was absent in 800 reference alleles. After this discovery, SCN4B was analyzed in 262 genotype-negative LQTS patients (96% white), but no further mutations were found. L179F was engineered by site-directed mutagenesis and heterologously expressed in HEK293 cells that contained the stably expressed SCN5A-encoded sodium channel α-subunit (hNaV1.5). Compared with the wild-type, L179F-β4 caused an 8-fold (compared with SCN5A alone) and 3-fold (compared with SCN5A + WT-β4) increase in late sodium current consistent with the molecular/electrophysiological phenotype previously shown for LQTS-associated mutations. Conclusions We provide the seminal report of SCN4B-encoded Navβ4 as a novel LQT3-susceptibility gene. PMID:17592081

  6. High-precision Velocimetry Reveals δ Cephei's Secret Companion

    NASA Astrophysics Data System (ADS)

    Anderson, Richard I.; Sahlmann, Johannes; Holl, Berry; Eyer, Laurent

    2015-08-01

    The search for extra-solar planets has driven tremendous improvements in the precision of radial velocities measured with high-resolution echelle spectrographs. However, relatively few studies have as of yet exploited the present-day extreme (m/s) instrumental precision to study Cepheid variable stars.We have been observing the prototype of classical Cepheids, δ Cephei, since September 2011 using the HERMES spectrograph mounted to the Mercator telescope located at the Roque de los Muchachos Observatory on the island of La Palma. Being one of the most-studied variable stars, we originally chose δ Cephei as a maximum-precision reference for other Cepheids in our sample. To our great surprise however, we discovered a clear orbital signature in the homogeneous HERMES data. Adding in radial velocity data from the literature, we then determined δ Cephei's orbit (cf. Anderson et al. 2015, arXiv:1503.04116). The high orbital eccentricity (e=0.647) leads to close pericenter passages (rmin ~ 9.5 RδCep) which suggest an intriguing past that requires further study, since Cepheids are well-known magnifying glasses for stellar evolution (Kippenhahn & Weigert 1994). We furthermore determined a new parallax to δ Cephei (using Hipparcos data) that is in tension with previous estimates and shows that the orbit will have to be accounted for when measuring δ Cephei's parallax with Gaia.While some of our HERMES data are as precise as 9 m/s, we found correlated excess residuals when removing the reference pulsation model and orbital motion from the HERMES radial velocity data, leaving an RMS of 47 m/s. These higher-than-expected residuals are reminiscent of the "period-jitter" or "flickering" observed in high-precision photometry of Cepheids obtained with the Kepler and MOST satellites. This reveals a fortuitous synergy between variable stars studies and the field of exoplanet research and opens the window for a better understanding of Cepheid pulsations via high

  7. North Atlantic tropical cyclone track migration since 1550 A.D. revealed using a Belizean stalagmite

    NASA Astrophysics Data System (ADS)

    Baldini, Lisa; Baldini, James; Frappier, Amy; Ridley, Harriet; Asmerom, Yemane; Prufer, Keith; Breitenbach, Sebastian; Aquino, Valorie; Polyak, Victor; Awe, Jaime

    2015-04-01

    A gradual shift in the geographic distribution of hurricanes and tropical storms from the western Caribbean to the US Atlantic Coast between 1550 and 1983 A.D. is revealed by an annually-resolved, 456-year record of tropical cyclone (TC) activity reconstructed using sub-annually resolved carbon and oxygen isotope ratios in stalagmite YOK-G from Yok Balum Cave, southern Belize. Annual geochemical cycles combined with 230Th dating provide excellent chronological control, and the hurricane season signal intensity is reconstructed using seasonally-specific isotope ratios. The stalagmite hurricane season signal correlates very well with HURDAT2 western Caribbean TC count over the calibration period (1945-1983) as well as over the 25-year verification period. Our record suggests very few TCs affected the western Caribbean in the mid-1500s, but that this was followed by gradually rising western Caribbean TC activity that peaked during the Little Ice Age (LIA). Western Caribbean TC activity then decreases gradually from the mid-1600s to present day, with abrupt shifts at 1790 A.D. and 1870 A.D. Comparison with basin-wide TC reconstructions reveals a northward shift in the geographic distribution of TC impacts over the past few hundred years, from dominantly western Caribbean during the LIA to substantially more along the North American Atlantic margin during the 20th Century. Our reconstruction suggests that NAO variability played a major role in driving these shifts in dominant storm tracks through time.

  8. REVEAL: Software Documentation and Platform Migration

    NASA Technical Reports Server (NTRS)

    Wilson, Michael A.; Veibell, Victoir T.; Freudinger, Lawrence C.

    2008-01-01

    The Research Environment for Vehicle Embedded Analysis on Linux (REVEAL) is reconfigurable data acquisition software designed for network-distributed test and measurement applications. In development since 2001, it has been successfully demonstrated in support of a number of actual missions within NASA s Suborbital Science Program. Improvements to software configuration control were needed to properly support both an ongoing transition to operational status and continued evolution of REVEAL capabilities. For this reason the project described in this report targets REVEAL software source documentation and deployment of the software on a small set of hardware platforms different from what is currently used in the baseline system implementation. This report specifically describes the actions taken over a ten week period by two undergraduate student interns and serves as a final report for that internship. The topics discussed include: the documentation of REVEAL source code; the migration of REVEAL to other platforms; and an end-to-end field test that successfully validates the efforts.

  9. Revealing advantage in a quantum network

    NASA Astrophysics Data System (ADS)

    Mukherjee, Kaushiki; Paul, Biswajit; Sarkar, Debasis

    2016-07-01

    The assumption of source independence was used to reveal nonlocal (apart from standard Bell-CHSH scenario) nature of correlations generated in entanglement swapping experiments. In this work, we have discussed the various utilities of this assumption to reveal nonlocality (via generation of nonbilocal correlations) and thereby exploiting quantumness under lesser requirements compared to some standard means of doing the same. We have also provided with a set of sufficient criteria, imposed on the states (produced by the sources) under which source independence can reveal nonbilocal nature of correlations in a quantum network.

  10. The Geology of Pluto and Charon as Revealed by New Horizons

    NASA Astrophysics Data System (ADS)

    Moore, Jeffrey M.; Spencer, John R.; McKinnon, William B.; Stern, S. Alan; Young, Leslie A.; Weaver, Harold A.; Olkin, Cathy B.; Ennico, Kim; New Horizons GGI Team

    2016-04-01

    NASA's New Horizons spacecraft has revealed that Pluto and Charon exhibit strikingly different surface appearances, despite their similar densities and presumed bulk compositions. Much of Pluto's surface can be attributed to surface-atmosphere interactions and the mobilization of volatile ices by insolation. Many valley systems appear to be the consequence of glaciation involving nitrogen ice. Other geological activity requires or required internal heating. The convection and advection of volatile ices in Sputnik Planum can be powered by present-day radiogenic heat loss. On the other hand, the prominent mountains at the western margin of Sputnik Planum, and the strange, multi-km-high mound features to the south, probably composed of H2O, are young geologically as inferred by light cratering and superposition relationships. Their origin, and what drove their formation so late in Solar System history, is under investigation. The dynamic remolding of landscapes by volatile transport seen on Pluto is not unambiguously evident on Charon. Charon does, however, display a large resurfaced plain and globally engirdling extensional tectonic network attesting to its early endogenic vigor.

  11. Stability of active mantle upwelling revealed by net characteristics of plate tectonics.

    PubMed

    Conrad, Clinton P; Steinberger, Bernhard; Torsvik, Trond H

    2013-06-27

    Viscous convection within the mantle is linked to tectonic plate motions and deforms Earth's surface across wide areas. Such close links between surface geology and deep mantle dynamics presumably operated throughout Earth's history, but are difficult to investigate for past times because the history of mantle flow is poorly known. Here we show that the time dependence of global-scale mantle flow can be deduced from the net behaviour of surface plate motions. In particular, we tracked the geographic locations of net convergence and divergence for harmonic degrees 1 and 2 by computing the dipole and quadrupole moments of plate motions from tectonic reconstructions extended back to the early Mesozoic era. For present-day plate motions, we find dipole convergence in eastern Asia and quadrupole divergence in both central Africa and the central Pacific. These orientations are nearly identical to the dipole and quadrupole orientations of underlying mantle flow, which indicates that these 'net characteristics' of plate motions reveal deeper flow patterns. The positions of quadrupole divergence have not moved significantly during the past 250 million years, which suggests long-term stability of mantle upwelling beneath Africa and the Pacific Ocean. These upwelling locations are positioned above two compositionally and seismologically distinct regions of the lowermost mantle, which may organize global mantle flow as they remain stationary over geologic time. PMID:23803848

  12. The Chlamydial Type III Secretion Mechanism: Revealing Cracks in a Tough Nut

    PubMed Central

    Betts-Hampikian, Helen Jennifer; Fields, Kenneth A.

    2010-01-01

    Present-day members of the Chlamydiaceae contain parasitic bacteria that have been co-evolving with their eukaryotic hosts over hundreds of millions of years. Likewise, a type III secretion system encoded within all genomes has been refined to complement the unique obligate intracellular niche colonized so successfully by Chlamydia spp. All this adaptation has occurred in the apparent absence of the horizontal gene transfer responsible for creating the wide range of diversity in other Gram-negative, type III-expressing bacteria. The result is a system that is, in many ways, uniquely chlamydial. A critical mass of information has been amassed that sheds significant light on how the chlamydial secretion system functions and contributes to an obligate intracellular lifestyle. Although the overall mechanism is certainly similar to homologous systems, an image has emerged where the chlamydial secretion system is essential for both survival and virulence. Numerous apparent differences, some subtle and some profound, differentiate chlamydial type III secretion from others. Herein, we provide a comprehensive review of the current state of knowledge regarding the Chlamydia type III secretion mechanism. We focus on the aspects that are distinctly chlamydial and comment on how this important system influences chlamydial pathogenesis. Gaining a grasp on this fascinating system has been challenging in the absence of a tractable genetic system. However, the surface of this tough nut has been scored and the future promises to be fruitful and revealing. PMID:21738522

  13. Microevolution of nematode miRNAs reveals diverse modes of selection.

    PubMed

    Jovelin, Richard; Cutter, Asher D

    2014-01-01

    Micro-RNA (miRNA) genes encode abundant small regulatory RNAs that play key roles during development and in homeostasis by fine tuning and buffering gene expression. This layer of regulatory control over transcriptional networks is preserved by selection across deep evolutionary time, yet selection pressures on individual miRNA genes in contemporary populations remain poorly characterized in any organism. Here, we quantify nucleotide variability for 129 miRNAs in the genome of the nematode Caenorhabditis remanei to understand the microevolution of this important class of regulatory genes. Our analysis of three population samples and C. remanei's sister species revealed ongoing natural selection that constrains evolution of all sequence domains within miRNA hairpins. We also show that new miRNAs evolve faster than older miRNAs but that selection nevertheless favors their persistence. Despite the ongoing importance of purging of new mutations, we discover a trove of >400 natural miRNA sequence variants that include single nucleotide polymorphisms in seed motifs, indels that ablate miRNA functional domains, and origination of new miRNAs by duplication. Moreover, we demonstrate substantial nucleotide divergence of pre-miRNA hairpin alleles between populations and sister species. These findings from the first global survey of miRNA microevolution in Caenorhabditis support the idea that changes in gene expression, mediated through divergence in miRNA regulation, can contribute to phenotypic novelty and adaptation to specific environments in the present day as well as the distant past. PMID:25355809

  14. Lead isotopes reveal bilateral asymmetry and vertical continuity in the Hawaiian mantle plume.

    PubMed

    Abouchami, W; Hofmann, A W; Galer, S J G; Frey, F A; Eisele, J; Feigenson, M

    2005-04-14

    The two parallel chains of Hawaiian volcanoes ('Loa' and 'Kea') are known to have statistically different but overlapping radiogenic isotope characteristics. This has been explained by a model of a concentrically zoned mantle plume, where the Kea chain preferentially samples a more peripheral portion of the plume. Using high-precision lead isotope data for both centrally and peripherally located volcanoes, we show here that the two trends have very little compositional overlap and instead reveal bilateral, non-concentric plume zones, probably derived from the plume source in the mantle. On a smaller scale, along the Kea chain, there are isotopic differences between the youngest lavas from the Mauna Kea and Kilauea volcanoes, but the 550-thousand-year-old Mauna Kea lavas are isotopically identical to Kilauea lavas, consistent with Mauna Kea's position relative to the plume, which was then similar to that of present-day Kilauea. We therefore conclude that narrow (less than 50 kilometres wide) compositional streaks, as well as the larger-scale bilateral zonation, are vertically continuous over tens to hundreds of kilometres within the plume. PMID:15829954

  15. Ethiopian Genetic Diversity Reveals Linguistic Stratification and Complex Influences on the Ethiopian Gene Pool

    PubMed Central

    Pagani, Luca; Kivisild, Toomas; Tarekegn, Ayele; Ekong, Rosemary; Plaster, Chris; Gallego Romero, Irene; Ayub, Qasim; Mehdi, S. Qasim; Thomas, Mark G.; Luiselli, Donata; Bekele, Endashaw; Bradman, Neil; Balding, David J.; Tyler-Smith, Chris

    2012-01-01

    Humans and their ancestors have traversed the Ethiopian landscape for millions of years, and present-day Ethiopians show great cultural, linguistic, and historical diversity, which makes them essential for understanding African variability and human origins. We genotyped 235 individuals from ten Ethiopian and two neighboring (South Sudanese and Somali) populations on an Illumina Omni 1M chip. Genotypes were compared with published data from several African and non-African populations. Principal-component and STRUCTURE-like analyses confirmed substantial genetic diversity both within and between populations, and revealed a match between genetic data and linguistic affiliation. Using comparisons with African and non-African reference samples in 40-SNP genomic windows, we identified “African” and “non-African” haplotypic components for each Ethiopian individual. The non-African component, which includes the SLC24A5 allele associated with light skin pigmentation in Europeans, may represent gene flow into Africa, which we estimate to have occurred ∼3 thousand years ago (kya). The non-African component was found to be more similar to populations inhabiting the Levant rather than the Arabian Peninsula, but the principal route for the expansion out of Africa ∼60 kya remains unresolved. Linkage-disequilibrium decay with genomic distance was less rapid in both the whole genome and the African component than in southern African samples, suggesting a less ancient history for Ethiopian populations. PMID:22726845

  16. Hiding personal information reveals the worst

    PubMed Central

    John, Leslie K.; Barasz, Kate; Norton, Michael I.

    2016-01-01

    Seven experiments explore people’s decisions to share or withhold personal information, and the wisdom of such decisions. When people choose not to reveal information—to be “hiders”—they are judged negatively by others (experiment 1). These negative judgments emerge when hiding is volitional (experiments 2A and 2B) and are driven by decreases in trustworthiness engendered by decisions to hide (experiments 3A and 3B). Moreover, hiders do not intuit these negative consequences: given the choice to withhold or reveal unsavory information, people often choose to withhold, but observers rate those who reveal even questionable behavior more positively (experiments 4A and 4B). The negative impact of hiding holds whether opting not to disclose unflattering (drug use, poor grades, and sexually transmitted diseases) or flattering (blood donations) information, and across decisions ranging from whom to date to whom to hire. When faced with decisions about disclosure, decision-makers should be aware not just of the risk of revealing, but of what hiding reveals. PMID:26755591

  17. Genetic analysis of 17 Y-STRs in a Mestizo population from the Central Valley of Mexico.

    PubMed

    Santana, Carla; Noris, Gino; Meraz-Ríos, Marco Antonio; Magaña, Jonathan J; Calderon-Aranda, Emma S; Muñoz, Maria de Lourdes; Gómez, Rocío

    2014-01-01

    This study aims to portray the complex diversity of the Mexican Mestizo population, which represents 98.8% of the entire population of Mexico. We compiled extended haplotype data of the Y chromosome from populations in the Central Valley of Mexico (CVM), which we compared with other Mestizo and parental (Amerindian, European, and African) populations. A complex ancestral relationship was found in the CVM population, suggesting cosmopolitan origins. Nevertheless, the most preeminent lineages point toward a European ancestry, where the R1b lineage was most frequent. In addition, important frequencies of Amerindian lineages were also found in the Mestizo sample studied. Interestingly, the Amerindian ancestry showed a remarkable substructure, which was represented by the two main founding lineages: QL54 (× M3) and M3. However, even within each lineage a high diversity was found despite the small number of sample bearers of these lineages. Further, we detected important genetic differences between the CVM populations and the Mexican Mestizo populations from the north and south. This result points to the fact that Mestizo populations present different ancestral proportions, which are related to the demographic events that gave origin to each population. Finally, we provide additional forensic statistical parameters that are useful in the interpretation of genetic analysis where autosomal loci are limited. Our findings illustrate the complex genetic background of the Mexican Mestizo population and reinforce the need to encompass more geographic regions to generate more robust data for forensic applications. PMID:25959695

  18. Delta-sarcoglycan gene polymorphism frequency in Amerindian and Mestizo populations of Mexico.

    PubMed

    Ordoñez-Razo, Rosa María; Canizales-Quinteros, Samuel; Rodríguez-Cruz, Maricela; Peñaloza, Rosenda; Minauro-Sanmiguel, Fernando; Canto-Cetina, Thelma; Canto, Patricia; Coral-Vázquez, Ramón; Salamanca-Gómez, Fabio

    2010-04-01

    Mutations on the delta-sarcoglycan gene have been associated with the development of both hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy. Recently, the polymorphism c.-94C>G was associated with HCM in Japanese patients. The aim of our study was to evaluate the frequency of c.-94C>G polymorphism in Mexican-Amerindian and Mexican-Mestizo populations. We analyzed the frequency of this polymorphism in 165 Mexican-Amerindian individuals (23 Triquis, 25 Zapotecos, 24 Mayas, 41 Nahuas, and 52 Mixtecos) and 100 unrelated Mexican-Mestizos. Allele frequencies were similar in all Amerindian groups (0.33 Triquis, 0.54 Zapotecos, 0.54 Mayas, 0.46 Nahuas, and 0.49 Mixtecos). When compared with Mexican-Mestizos, only Triquis were different (p = 0.00742). However, when comparing the total sample of the Amerindian population with the Mestizos, the difference was not significant (p = 0.12225). Allele frequencies of Mexican populations were higher than in Asians and less than African and European populations (p < 0.05). These data show that the distribution of the C allele is higher in Mexican populations studied and consequently it is necessary to define if this may be associated with genetic susceptibility for HCM in the Mexican patients. PMID:20384457

  19. REVEAL: Software Documentation and Platform Migration

    NASA Technical Reports Server (NTRS)

    Wilson, Michael A.; Veibell, Victoir T.

    2011-01-01

    The Research Environment for Vehicle Embedded Analysis on Linux (REVEAL) is reconfigurable data acquisition software designed for network-distributed test and measurement applications. In development since 2001, it has been successfully demonstrated in support of a number of actual missions within NASA's Suborbital Science Program. Improvements to software configuration control were needed to properly support both an ongoing transition to operational status and continued evolution of REVEAL capabilities. For this reason the project described in this report targets REVEAL software source documentation and deployment of the software on a small set of hardware platforms different from what is currently used in the baseline system implementation. This presentation specifically describes the actions taken over a ten week period by two undergraduate student interns and serves as an overview of the content of the final report for that internship.

  20. Multidisciplinary investigation (ERT, CO2, SP and T) reveals fluid circulation at Somma-Vesuvius

    NASA Astrophysics Data System (ADS)

    Poret, Matthieu; Ricci, Tullio; Finizola, Anthony; Delcher, Eric; Peltier, Aline

    2016-04-01

    Somma-Vesuvius volcano, located near the city of Naples, threatens about 800,000 peoples producing one of the highest volcanic risk in the world. In the framework of the EC FP7 project "MEDiterranean SUpersite Volcanoes" a multidisciplinary investigation was performed in March 2014. This survey aimed (1) at locating the present-day hydrothermal system of Somma-Vesuvius and (2) at identifying the preferential paths and fluid flows inside the volcano.
 The prospecting methods used were Electrical Resistivity Tomography (ABEM SAS 4000) with 64 electrodes at 40 m spacing (in Wenner alpha configuration), self-potential (SP), temperature (30 cm depth) and CO2 concentration in the soil at 20 m spacing. All the measurements were performed along a 7 km long profile completed with roll-along (North- West to South-East). The depth of investigation for ERT reached about 500 m. This method revealed an electrical conductive body (20-100 ohm.m) centered beneath the summit of the Vesuvius cone. This conductive body was interpreted as the present-day hydrothermal system of the volcanic complex. Regarding the shape of this structure we noticed a deeply different shape respect to the one observed on both Stromboli and Vulcano volcanoes. Indeed, the Vesuvius hydrothermal system appears to act as a body which is constrained up to 200-250 m below the surface and, moreover, also emphasized by the W-like shape of the SP signal. From ERT and SP results a diameter of around 1.7 km at the maximum depth of investigation is estimated for the hydrothermal system of Somma-Vesuvius.
 In addition, four weak thermal anomalies (6-13°C) are identified on the summit area. They can be explained as preferential paths of up-flowing fluids. It follows that the largest structure seen on both temperature signal and ERT tomography is related to the crater rim of the 1906 eruption. Furthermore, on both lower sides of Vesuvius cone a conductive body (300-600 ohm.m) is identified within a resistive

  1. Omics strategies for revealing Yersinia pestis virulence

    PubMed Central

    Yang, Ruifu; Du, Zongmin; Han, Yanping; Zhou, Lei; Song, Yajun; Zhou, Dongsheng; Cui, Yujun

    2012-01-01

    Omics has remarkably changed the way we investigate and understand life. Omics differs from traditional hypothesis-driven research because it is a discovery-driven approach. Mass datasets produced from omics-based studies require experts from different fields to reveal the salient features behind these data. In this review, we summarize omics-driven studies to reveal the virulence features of Yersinia pestis through genomics, trascriptomics, proteomics, interactomics, etc. These studies serve as foundations for further hypothesis-driven research and help us gain insight into Y. pestis pathogenesis. PMID:23248778

  2. Record of Subducting Topography revealed in 3D Seismic Imaging of Pleistocene unconformities, offshore Southern Costa Rica

    NASA Astrophysics Data System (ADS)

    Edwards, J. H.; Kluesner, J. W.; Silver, E. A.

    2015-12-01

    3D seismic reflection data (CRISP) collected across the southern Costa Rica forearc reveals broad, survey-wide erosional events in the upper ~1 km of slope sediments in the mid-slope to outer shelf. The upper 0-280 m of continuous, weakly deformed sediments, designated by IODP Expedition 344 as structural domain I, is bounded by a major erosional event, (CRISP-U1, dated near 1 Ma), suggesting wave-plain erosion from the present shelf break out to 25 km seaward, to a present-day water depth of 900-1300 m. The eastern toe of its surface is characterized by a large drainage system, likely including submarine channels that eroded to depths >1500 m below present-day water depth. CRISP-U1 is variably uplifted by a series of fault propagation folds and cut by an intersecting array of normal faults. Another, major erosional event, (CRISP-M1, approximately 2 Ma) extended from the outer shelf to the mid slope and removed 500-1000 m of material. Overlying CRISP-M1 is up to 1 km of sediments that are more deformed by fault propagation folds, back thrusts, and intersecting arrays of normal faults. Unconformities with smaller areal extent are variably found in these overlying sediments across the mid-slope to outer shelf, at present-day water depths >220 m. Below CRISP-M1, sediments are more densely deformed and also contain major unconformities that extend survey-wide. Both unconformities, CRISP-U1 and CRISP-M1, are encountered in well U1413 and are demarcated by major benthic foraminifera assemblage changes at 149 mbsf and ~504 mbsf (Harris et al., 2013, Proceeding of the IODP, Volume 344).CRISP-M1 is likely correlative to the major sediment facies and benthic foraminifera assemblage change found in U1379 at ~880 mbsf (Vannuchi et al., 2013). The unconformities and intersecting array of normal faults may demarcate the passing of topography on the downgoing Cocos plate, episodically lifting and then subsiding the Costa Rica margin, with amplitudes up to about 1 km.

  3. The evolution of paediatrics from archaeological times to the mid-nineteenth century and the historical influence on present day practice.

    PubMed

    Rangroo, Vinita

    2008-05-01

    The history of childcare dates back to the beginning of time. This article critically analyses the history of paediatrics from its roots to mid-nineteenth century with the view to examine its evolution and influence on today's practice. Paediatrics as a sub-speciality of medicine only began in the fifteenth century when the Four Incunabula were published in the West. This was the first attempt at producing a comprehensive and accessible reference paediatric text. However, long before the Incunabula, early traces of childcare are found in different cultures like Egyptian, Indian and Chinese. Modern paediatrics is a highly advanced field of medicine that relies on many recent technological innovations. In spite of these, this paper concludes that paediatrics today is very much based on concepts, such as observation and clinical skills, introduced many centuries ago. The basic approach used in everyday clinical practice owes more to century-old ideas of scientists. PMID:18394119

  4. "Rule of Thumb Methods No Longer Suffice": Development of British Coal Industry Education and Training 1900-circa 1970 and Lessons for Present-Day Education Policy-Makers

    ERIC Educational Resources Information Center

    Walker, Martyn A.

    2015-01-01

    This paper traces the origins and development of coal mining education and training in Britain from 1900 to the 1970s, by which time the coal industry had substantially declined. It looks at the progress from working-class self-help to national policy in support of education and training. The research makes use of college prospectuses and…

  5. Higher Education as a Means of Upward Social Mobility: The Expectations of Graduates and the Realities of Present-Day Society

    ERIC Educational Resources Information Center

    Burlutskaia, M. G.

    2014-01-01

    Research data show that higher education in Russia is less of a vehicle of upward mobility than it was in earlier times, not least because it is becoming less of an advantage as the percentage of people with degrees increases. This raises questions about what the goals of higher education should be, and of how to prepare young people for the job…

  6. Radiation of the Australian flora: what can comparisons of molecular phylogenies across multiple taxa tell us about the evolution of diversity in present-day communities?

    PubMed Central

    Crisp, Mike; Cook, Lyn; Steane, Dorothy

    2004-01-01

    The Australian fossil record shows that from ca. 25 Myr ago, the aseasonal-wet biome (rainforest and wet heath) gave way to the unique Australian sclerophyll biomes dominated by eucalypts, acacias and casuarinas. This transition coincided with tectonic isolation of Australia, leading to cooler, drier, more seasonal climates. From 3 Myr ago, aridification caused rapid opening of the central Australian arid zone. Molecular phylogenies with dated nodes have provided new perspectives on how these events could have affected the evolution of the Australian flora. During the Mid-Cenozoic (25-10 Myr ago) period of climatic change, there were rapid radiations in sclerophyll taxa, such as Banksia, eucalypts, pea-flowered legumes and Allocasuarina. At the same time, taxa restricted to the aseasonal-wet biome (Nothofagus, Podocarpaceae and Araucariaceae) did not radiate or were depleted by extinction. During the Pliocene aridification, two Eremean biome taxa (Lepidium and Chenopodiaceae) radiated rapidly after dispersing into Australia from overseas. It is clear that the biomes have different histories. Lineages in the aseasonal-wet biome are species poor, with sister taxa that are species rich, either outside Australia or in the sclerophyll biomes. In conjunction with the fossil record, this indicates depletion of the Australian aseasonal-wet biome from the Mid-Cenozoic. In the sclerophyll biomes, there have been multiple exchanges between the southwest and southeast, rather than single large endemic radiations after a vicariance event. There is need for rigorous molecular phylogenetic studies so that additional questions can be addressed, such as how interactions between biomes may have driven the speciation process during radiations. New studies should include the hitherto neglected monsoonal tropics. PMID:15519972

  7. A new chemistry-climate tropospheric and stratospheric model MOCAGE-Climat: evaluation of the present-day climatology and sensitivity to surface processes

    NASA Astrophysics Data System (ADS)

    Teyssèdre, H.; Michou, M.; Clark, H. L.; Josse, B.; Karcher, F.; Olivié, D.; Peuch, V.-H.; Saint-Martin, D.; Cariolle, D.; Attié, J.-L.; Ricaud, P.; van der A, R. J.; Chéroux, F.

    2007-08-01

    We present the chemistry-climate configuration of the Météo-France Chemistry and Transport Model, MOCAGE-Climat. MOCAGE-Climat is a state-of-the-art model that simulates the global distribution of ozone and its precursors (82 chemical species) both in the troposphere and the stratosphere, up to the mid-mesosphere (~70 km). Surface processes (emissions, dry deposition), convection, and scavenging are explicitly described in the model that has been driven by the ECMWF operational analyses of the period 2000-2005, on T21 and T42 horizontal grids and 60 hybrid vertical levels, with and without a procedure that reduces calculations in the boundary layer, and with on-line or climatological deposition velocities. Model outputs have been compared to available observations, both from satellites (TOMS, HALOE, SMR, SCIAMACHY, MOPITT) and in-situ instrument measurements (ozone sondes, MOZAIC and aircraft campaigns) at climatological timescales. The distribution of long-lived species is in fair agreement with observations in the stratosphere putting apart shortcomings linked to the large-scale circulation. The variability of the ozone column, both spatially and temporarily, is satisfactory. However, the too fast Brewer-Dobson circulation accumulates too much ozone in the lower to mid-stratosphere at the end of winter. Ozone in the UTLS region does not show any systematic bias. In the troposphere better agreement with ozone sonde measurements is obtained at mid and high latitudes than in the tropics and differences with observations are the lowest in summer. Simulations using a simplified boundary layer lead to ozone differences between the model and the observations up to the mid-troposphere. NOx in the lowest troposphere is in general overestimated, especially in the winter months over the northern hemisphere, which might result from a positive bias in OH. Dry deposition fluxes of O3 and nitrogen species are within the range of values reported by recent inter-comparison model exercises. The use of climatological deposition velocities versus deposition velocities calculated on-line had greatest impact on HNO3 and NO2 in the troposphere.

  8. The Danger of Not Facing History: Exploring the Link between Education about the Past and Present-Day Anti-Semitism and Racism in Hungary

    ERIC Educational Resources Information Center

    van Iterson, Swaan; Nenadovic, Maja

    2013-01-01

    Until a few years ago the international media devoted scant attention to Hungary. Recently, however, multiple news reports and analyses have expressed concern about rising racism and extremism in this country, as well as a sense that the country's democracy is unraveling. It has often been argued that economic hardship is an important contributor…

  9. Observations and modeling of northern mid-latitude recurring slope lineae (RSL) suggest recharge by a present-day martian briny aquifer

    NASA Astrophysics Data System (ADS)

    Stillman, David E.; Michaels, Timothy I.; Grimm, Robert E.; Hanley, Jennifer

    2016-02-01

    Recurring slope lineae (RSL) are narrow (0.5-5 m) dark features on Mars that incrementally lengthen down steep slopes, fade in colder seasons, and recur annually. These features have been identified from the northern to southern mid-latitudes. Here, we describe how observations of northern mid-latitude RSL in northern Chryse Planitia and southwestern Acidalia Planitia (CAP) suggest that brines start flowing before northern spring equinox and continue for more than half a Mars-year (490 ± 40 sols, spanning solar longitude 337° ± 11°-224° ± 20°). All CAP RSL are found on the steep slopes of craters and their source zones are at or below the elevation of the surrounding plains. Spacecraft-derived surface temperature observations cannot resolve individual RSL, so thermal modeling was used to determine that CAP RSL have a freezing temperature of 238-252 K, freeze and melt diurnally, and flow only occurs within the top ∼8 cm of the regolith. Furthermore, we calculate that a typical CAP RSL has a water budget of 1.5-5.6 m3/m of headwall. Therefore, such a large water budget makes annual recharge via atmospheric or subsurface diffusion sources unlikely. Alternatively, we hypothesize that the most plausible RSL source is a briny aquifer with a freezing temperature less than or equal to the mean annual CAP surface temperature (220-225 K). The annual cycle is as follows: in late autumn, the shallowest part of the brine feeding the source zone freezes, forming an ice dam. As spring approaches, temperatures rise and the dam is breached. Brine is discharged and the RSL initially lengthens rapidly (>1.86 m/sol), the lengthening rate then slows considerably, to ∼0.25 m/sol. Eventually, the losses equal the discharge rate and the RSL reaches its equilibrium phase. As brine flows in the RSL some of the water is lost to the atmosphere, therefore the freezing temperature of the brine within the RSL is higher (238-252 K) as the brine transitions to a super-eutectic salt concentration. In the late autumn, falling temperatures restore the ice dam and the H2O in the RSL slowly sublimates away. Overall, CAP RSL possess a significantly different seasonality and much longer duration than typical southern mid-latitude RSL, suggesting that RSL at different latitude bands have different source types. Lastly, CAP RSL are the best evidence that shallow groundwater may still exist on Mars.

  10. Control of hyper-extended passive margin architecture on subduction initiation with application to the Alps and present-day North Atlantic ocean

    NASA Astrophysics Data System (ADS)

    Candioti, Lorenzo; Bauville, Arthur; Picazo, Suzanne; Mohn, Geoffroy; Kaus, Boris

    2016-04-01

    Hyper-extended magma-poor margins are characterized by extremely thinned crust and partially serpentinized mantle exhumation. As this can act as a zone of weakness during a subsequent compression event, a hyper-extended margin can thus potentially facilitate subduction initiation. Hyper-extended margins are also found today as passive margins fringing the Atlantic and North Atlantic ocean, e.g. Iberia and New Foundland margins [1] and Porcupine, Rockwall and Hatton basins. It has been proposed in the literature that hyper-extension in the Alpine Tethys does not exceed ~600 km in width [2]. The geodynamical evolution of the Alpine and Atlantic passive margins are distinct: no subduction is yet initiated in the North Atlantic, whereas the Alpine Tethys basin has undergone subduction. Here, we investigate the control of the presence of a hyper-extended margin on subduction initiation. We perform high resolution 2D simulations considering realistic rheologies and temperature profiles for these locations. We systematically vary the length and thickness of the hyper-extended crust and serpentinized mantle, to better understand the conditions for subduction initiation. References: [1] G. Manatschal. New models for evolution of magma-poor rifted margins based on a review of data and concepts from West Iberia and the Alps. Int J Earth Sci (Geol Rundsch) (2004); 432-466. [2] G. Mohn, G. Manatschal, M. Beltrando, I. Haupert. The role of rift-inherited hyper-extension in alpine-type orogens. Terra Nova (2014); 347-353.

  11. Echinometra sea urchins acclimatized to elevated pCO2 at volcanic vents outperform those under present-day pCO2 conditions.

    PubMed

    Uthicke, Sven; Ebert, Thomas; Liddy, Michelle; Johansson, Charlotte; Fabricius, Katharina E; Lamare, Miles

    2016-07-01

    Rising atmospheric CO2 concentrations will significantly reduce ocean pH during the 21st century (ocean acidification, OA). This may hamper calcification in marine organisms such as corals and echinoderms, as shown in many laboratory-based experiments. Sea urchins are considered highly vulnerable to OA. We studied an Echinometra species on natural volcanic CO2 vents in Papua New Guinea, where they are CO2 -acclimatized and also subjected to secondary ecological changes from elevated CO2 . Near the vent site, the urchins experienced large daily variations in pH (>1 unit) and pCO2 (>2000 ppm) and average pH values (pHT 7.73) much below those expected under the most pessimistic future emission scenarios. Growth was measured over a 17-month period using tetracycline tagging of the calcareous feeding lanterns. Average-sized urchins grew more than twice as fast at the vent compared with those at an adjacent control site and assumed larger sizes at the vent compared to the control site and two other sites at another reef near-by. A small reduction in gonad weight was detected at the vents, but no differences in mortality, respiration, or degree of test calcification were detected between urchins from vent and control populations. Thus, urchins did not only persist but actually 'thrived' under extreme CO2 conditions. We suggest an ecological basis for this response: Increased algal productivity under increased pCO2 provided more food at the vent, resulting in higher growth rates. The wider implication of our observation is that laboratory studies on non-acclimatized specimens, which typically do not consider ecological changes, can lead to erroneous conclusions on responses to global change. PMID:26762613

  12. The Hippest History: The Detritus of Your Library's Past Can Help with Your Present-Day Marketing, Fundraising, and Professional Pride

    ERIC Educational Resources Information Center

    Lear, Bernadette A.

    2005-01-01

    The author of this article studies the history of libraries. Few libraries capitalize on their own organizational history, however, even though it can be, at minimum, a resource of images and factoids for everything from answering administrative questions to crafting fundraising and marketing pieces. It can also be a reservoir of professional…

  13. A meta-analysis of coordinate systems and bibliography of their use on Pluto from Charon's discovery to the present day

    NASA Astrophysics Data System (ADS)

    Zangari, Amanda

    2015-01-01

    This paper aims to alleviate the confusion between many different ways of defining latitude and longitude on Pluto, as well as to help prevent future Pluto papers from drawing false conclusion due to problems with coordinates. In its 2009 meeting report, the International Astronomical Union Working Group on Cartographic Coordinates and Rotational Elements redefined Pluto coordinates to follow a right-handed system (Archinal, B.A., et al. [2011a]. Celest. Mech. Dynam. Astron. 109, 101-135; Archinal, B.A., et al. [2011b]. Celest. Mech. Dynam. Astron. 110, 401-403). However, before this system was redefined, both the previous system (defining the north pole to be north of the invariable plane), and the "new" system (the right-hand rule system) were commonly used. A summary of major papers on Pluto and the system each paper used is given. Several inconsistencies have been found in the literature. The vast majority of papers and most maps use the right-hand rule, which is now the IAU system and the system recommended here for future papers.

  14. Present-day to 21st century projections of secondary organic aerosol (SOA) from a global climate-aerosol model with an explicit SOA formation scheme

    NASA Astrophysics Data System (ADS)

    Lin, G.; Penner, J. E.; Zhou, C.

    2014-12-01

    Secondary organic aerosol (SOA) has been shown to be an important component of non-refractory submicron aerosol in the atmosphere. The presence of SOA can influence the earth's radiative balance by contributing to the absorption and scattering of radiation and by altering the properties of clouds. Globally, a large fraction of SOA originates from biogenic volatile organic compounds (BVOCs), emissions of which depend on vegetation cover and climate. Temperature, CO2 concentration, and land use and land cover change have been shown to be major drivers of global isoprene emission changes in future climates. Additionally, the SOA concentration in the atmosphere not only depends on BVOC emissions, but is also controlled by anthropogenic emissions, temperature, precipitation and the oxidative capacity of the atmosphere. To project the change in SOA concentrations in the future requires a model that fully couples a BVOC emission model that represents these BVOC emission drivers, together with a sophisticated atmospheric model of SOA formation and properties. Recent studies have suggested that traditional parameterized SOA formation mechanisms that are tuned to fit smog chamber data do not fully account for the complexity and dynamics of real SOA system, calling into the question of the validity and completeness of previous SOA projections. In this study, we investigate the response of SOA mass to future physical climate change, to land cover and land use change, to changes in BVOCs emissions, and to changes in anthropogenic aerosol and gas species emissions for the year 2100, utilizing a global climate-aerosol model (CAM5-IMPACT): the NCAR Community Atmospheric Model (CAM5) coupled with a global aerosol model (IMPACT). The IMPACT model has sophisticated detailed process-based mechanisms describing aerosol microphysics and SOA formation through both gas phase and multiphase reactions. We perform sensitivity tests to isolate the relative roles of individual global change drivers. The anthropogenic and biomass burning emissions are adopted from representative concentration pathways (RCP) scenarios for future (year 2100) simulations. Biogenic VOC species are predicted from MEGAN 2.1 (Model of Emissions of Gases and Aerosols from Nature, version 2.1) embedded in NCAR Community Land Model (CLM4.5).

  15. Mass balance of Graham Land at present-day and over the past 150 years using GRACE and GNSS station data

    NASA Astrophysics Data System (ADS)

    Ivins, E. R.; Wiese, D. N.; Watkins, M. M.; Landerer, F. W.; Simms, A.; Yuan, D. N.; Boening, C.; Domack, E. W.

    2014-12-01

    The Antarctic Peninsula has been warming at an anomalously high rate with respect to other parts of the globe for the past 115 years. The increased atmospheric and ocean warmth has caused both increased precipitation and loss of buttressing near the trunks of the numerous outlet glaciers that drain into the ocean. The measurements by space gravimetry (Gravity Recovery and Climate Experiment or 'GRACE') have been crucial to identifying the dominant role of losses in butressing in a decadal-scale total ice mass budget for the Peninsula north of about 69 °S. One of the major losses of butressing came at a time when the Larsen B Ice Shelf catastrophically disintegrated into the northernmost Weddell Sea in March of 2002, the same month that GRACE was launched into orbit. The solid Earth rebounded in phase with the speed-up of the unbutressed outlet glaciers as evidenced by GNSS station data. The process has been repeating itself throughout the northern Peninsula since the late 1980's. Larsen A Ice Shelf breakup (LAISb) occurred, for example, in the Austral summer of 1993. Rott et al. (2011) have estimated a velocity acceleration at the trunks of 11 LBISb outlet glaciers for which flux-gate mass transport can be measured. Butress loss caused an increase in discharge of 4.3 ± 1.6 Gt/a in 2008, relative to measurements that span 1995-1999 for 11 Larsen B feeding glaciers. GRACE analysis centers have now released 12 years of monthly solutions (RL05) for global mass change. Solutions for the region of the Peninsula north of 69 ° S (Graham Land) using both constrained and unconstrained mascon methods show 2003-2011 net ice loss to the oceans with a trend of greater than 32 Gt/yr (Ivins et al., 2011; Luthcke et al., 2013). A new set of mascon solutions developed by JPL (Wiese et al., 2014) provide a high-resolution look at the evolution of mass in the Antarctic Peninsula from 2003-2014. We employ a time-series from these solutions and discuss the evolution of mass changes over the past 12-150 years, the GNSS uplift rates and the GIA correction that can be retrieved from modeling. The solutions for Graham Land yield a trend of -29.8 ± 4.8 Gt/yr using a GIA correction of 6.9 ± 1.0 Gt/yr. We infer that much of this mass loss began at least 50 years ago, and we attempt to quantify this ice mass history as it drives a substantial viscoelastic flow in the mantle.

  16. Impact of present-day and future (1850-2200) ice sheet melting on regional climate in the fully coupled CESM

    NASA Astrophysics Data System (ADS)

    Lenaerts, Jan; van Kampenhout, Leo; Vizcaino, Miren; Le Bars, Dewi; van den Broeke, Michiel

    2015-04-01

    Earth's ice sheets are currently losing volume at an accelerating pace, thereby not only contributing to sea level rise, but also altering the global ocean freshwater budget. The latter potentially impacts ocean circulations, which in turn affects polar and global climate. However, state-of-the-art climate models (e.g. from CMIP5) do not include changing meltwater fluxes from ice sheets, since both ice dynamics and snow hydrology are poorly represented. Here we forced the fully coupled, ~1° resolution Community Earth System Model (CESM) with a best estimate of past (from 1850 onwards), present and future ice sheet freshwater forcing according to two climate change scenarios, RCP2.6 and RCP8.5, both until the year 2200. This dataset was constructed from observations and regional climate model output and contains high spatial (drainage basin) and temporal (daily) detail. We compare results of these CESM simulations to observations and benchmark CESM simulations, without ice sheet melting, and focus particularly on the North Atlantic region. We find that ice sheet melting leads to additional weakening in the meridional overturning circulation strength in the North Atlantic beyond the year 2100, with important consequences for the climate in northwestern Europe and Greenland itself.

  17. Partitioning of oblique convergence in the Northern Andes subduction zone: Migration history and the present-day boundary of the North Andean Sliver in Ecuador

    NASA Astrophysics Data System (ADS)

    Alvarado, A.; Audin, L.; Nocquet, J. M.; Jaillard, E.; Mothes, P.; Jarrín, P.; Segovia, M.; Rolandone, F.; Cisneros, D.

    2016-05-01

    Along the Ecuadorian margin, oblique subduction induces deformation of the overriding continental plate. For the last 15 Ma, both exhumation and tectonic history of Ecuador suggest that the northeastward motion of the North Andean Sliver (NAS) was accompanied by an eastward migration of its eastern boundary and successive progressively narrowing restraining bends. Here we present geologic data, earthquake epicenters, focal mechanisms, GPS results, and a revised active fault map consistent with this new kinematic model. All data sets concur to demonstrate that active continental deformation is presently localized along a single major fault system, connecting fault segments from the Gulf of Guayaquil to the eastern Andean Cordillera. Although secondary faults are recognized within the Cordillera, they accommodate a negligible fraction of relative motion compared to the main fault system. The eastern limit is then concentrated rather than distributed as first proposed, marking a sharp boundary between the NAS, the Inca sliver, and the Subandean domain overthrusting the South American craton. The NAS limit follows a northeast striking right-lateral transpressional strike-slip system from the Gulf of Guayaquil (Isla Puná) to the Andean Cordillera and with the north-south striking transpressive faults along the eastern Andes. Eastward migration of the restraining belt since the Pliocene, abandonment of the sutures and reactivation of north-south striking ancient fault zones lead to the final development of a major tectonic boundary south and east of the NAS, favoring its extrusion as a continental sliver, accommodating the oblique convergence of the Nazca oceanic plate toward South America.

  18. Climate SPHINX: High-resolution present-day and future climate simulations with an improved representation of small-scale variability

    NASA Astrophysics Data System (ADS)

    Davini, Paolo; von Hardenberg, Jost; Corti, Susanna; Subramanian, Aneesh; Weisheimer, Antje; Christensen, Hannah; Juricke, Stephan; Palmer, Tim

    2016-04-01

    The PRACE Climate SPHINX project investigates the sensitivity of climate simulations to model resolution and stochastic parameterization. The EC-Earth Earth-System Model is used to explore the impact of stochastic physics in 30-years climate integrations as a function of model resolution (from 80km up to 16km for the atmosphere). The experiments include more than 70 simulations in both a historical scenario (1979-2008) and a climate change projection (2039-2068), using RCP8.5 CMIP5 forcing. A total amount of 20 million core hours will be used at end of the project (March 2016) and about 150 TBytes of post-processed data will be available to the climate community. Preliminary results show a clear improvement in the representation of climate variability over the Euro-Atlantic following resolution increase. More specifically, the well-known atmospheric blocking negative bias over Europe is definitely resolved. High resolution runs also show improved fidelity in representation of tropical variability - such as the MJO and its propagation - over the low resolution simulations. It is shown that including stochastic parameterization in the low resolution runs help to improve some of the aspects of the MJO propagation further. These findings show the importance of representing the impact of small scale processes on the large scale climate variability either explicitly (with high resolution simulations) or stochastically (in low resolution simulations).

  19. Simulations of the HDO and H2O-18 atmospheric cycles using the NASA GISS general circulation model - Sensitivity experiments for present-day conditions

    NASA Technical Reports Server (NTRS)

    Jouzel, Jean; Koster, R. D.; Suozzo, R. J.; Russell, G. L.; White, J. W. C.

    1991-01-01

    Incorporating the full geochemical cycles of stable water isotopes (HDO and H2O-18) into an atmospheric general circulation model (GCM) allows an improved understanding of global delta-D and delta-O-18 distributions and might even allow an analysis of the GCM's hydrological cycle. A detailed sensitivity analysis using the NASA/Goddard Institute for Space Studies (GISS) model II GCM is presented that examines the nature of isotope modeling. The tests indicate that delta-D and delta-O-18 values in nonpolar regions are not strongly sensitive to details in the model precipitation parameterizations. This result, while implying that isotope modeling has limited potential use in the calibration of GCM convection schemes, also suggests that certain necessarily arbitrary aspects of these schemes are adequate for many isotope studies. Deuterium excess, a second-order variable, does show some sensitivity to precipitation parameterization and thus may be more useful for GCM calibration.

  20. The Nationalities Question-from Versailles to the Present Day. European Teachers' Seminar (Esneux, Belgium, April 18-19, 1991). Report.

    ERIC Educational Resources Information Center

    Delrot, Jacqueline

    This document is the report of a seminar convened for European teachers on the subject of the nationalities question. The conference was held in the wake of drastic changes that came with the collapse of Communism in Eastern Europe. Participants focused on the nationality and border issues that arose from the treaties that ended World War I. The…

  1. Present-day subglacial erosion efficiency inferred from sources and transport of glacial clasts in the North face of Mont Blanc

    NASA Astrophysics Data System (ADS)

    Mugnier, J. L.; Godon, C.; Buoncristiani, J. F.; Paquette, J. L.; Trouvé, E.

    2012-04-01

    The efficiency of erosional processes is classically considered from detrital composition at the outlet of a shed that reflects the rocks eroded within the shed. We adapt fluvial detrital thermochronology (DeCelles et al., 2004) and lithology (Attal and Lavé, 2006) methods to the subglacial streams of the north face of the Mont Blanc. The lithology of this area is composed by a ~303 Ma old granite intruded within an older poly metamorphic complex (orthogneisses). In this study,we use macroscopic criteria (~10 000 clasts) and Ur/Pb dating of zircons (~500 datings of sand grains) to determine the provenance of the sediment transported by the glacier and by the sub-glacial streams. Samples come from sediments collected around the glacier (above, below or laterally), from different bedrocks sources according to the surface flow lines and glacier characteristics (above or below the ELA; temperate or cold), and from different subglacial streams. A comparison between the proportion of granite and orthogneisses in these samples indicates that: 1) the supra load follows the flow lines of the glacier deduced from SAR images correlation and the displacement pattern excludes supra load mixing of the different sources; 2) the transport by the glacier does not mix the clasts issued from the sub-glacial erosion with the clasts issued from supraglacial deposition, except in the lower tongue where supraglacial streams and moulins move the supraglacial load from top to bottom; 3) the erosion rate beneath the glacier is very small: null beneath the cold ice but also very weak beneath the greatest part of the temperate glacier; the erosion increases significantly beneath the tongue, where supraglacial load incorporated at the base favors abrasion; 4) the glacial erosion rate beneath the tongue remains at least five time smaller than the erosion rate coming from non-glacial area. According to our results, we demonstrate that the glaciers of the Mont-Blanc north face protect the top of Europe from erosion. DeCelles et al., 2004, Earth and Planetary Science Letters, v. 227, p. 313-330. Attal and Lavé, 2006, Geol. Soc. Am. Spec. Publ. (S.D. Willett, N. Hovius, M.T. Brandon and D. Fisher, eds.), 398, p. 143-171.

  2. Distribution and mechanism of Neogene to present-day vertical axis rotations, Pacific-Australian Plate Boundary Zone, South Island, New Zealand

    NASA Astrophysics Data System (ADS)

    Little, Timothy A.; Roberts, Andrew P.

    1997-01-01

    Remarkably little knowledge exists about mechanisms of vertical axis rotation in continental crust. Steeply dipping basement rocks in South Island, New Zealand, provide an opportunity to map the distribution of rotations across the Pacific-Australian plate boundary zone, and to delineate boundaries of rotated blocks in unusual detail. We synthesize new structural data with new and existing paleomagnetic data, with geodetic data, and with patterns of Neogene-Quaternary faulting in the strike-slip Marlborough fault system. For the past 20 m.y., vertical axis rotations have been hinged about two crustal-scale boundaries near the east coast. The NE hinge accommodated ˜50° of early-middle Miocene clockwise rotation, which caused deformation of the eastern ends of the Alpine-Wairau and Clarence strike-slip faults. The SW hinge has accommodated a further 30°-50° of finite clockwise rotation since ˜4 Ma and deflects active fault traces. The locus of rotation has shifted southwestward astride a subduction margin that is lengthening in that direction. Rotating rocks are pinned to the south against a locked collision zone where the continental Chatham Rise impinges against the margin. Slip on inland strike-slip faults is transformed seaward across a zone of fault termination into rigid body rotation of a large continental block that has been thrust eastward over the downgoing subducted slab of the Pacific plate. The rotation mechanism is a "migrating hinge," which resembles a flexed telephone book. Strike-slip faults are translated through a brecciated hinge region that does not coincide with a fixed material line in the rock.

  3. A historical to present-day account of efforts to answer the question, “What puts the brakes on mammalian hair cell regeneration?”

    PubMed Central

    Burns, Joseph C.; Corwin, Jeffrey T.

    2013-01-01

    Hearing and balance deficits often affect humans and other mammals permanently, because their ears stop producing hair cells within a few days after birth. But production occurs throughout life in the ears of sharks, bony fish, amphibians, reptiles, and birds allowing them to replace lost hair cells and quickly recover after temporarily experiencing the kinds of sensory deficits that are irreversible for mammals. Since the mid 1970's, researchers have been asking what puts the brakes on hair cell regeneration in mammals? Here we evaluate the headway that has been made and assess current evidence for various alternative mechanistic hypotheses that have been proposed to account for the limits to hair cell regeneration in mammals. PMID:23333259

  4. Factors controlling present-day tufa dynamics in the Monasterio de Piedra Natural Park (Iberian Range, Spain): depositional environmental settings, sedimentation rates and hydrochemistry

    NASA Astrophysics Data System (ADS)

    Vázquez-Urbez, M.; Arenas, C.; Sancho, C.; Osácar, C.; Auqué, L.; Pardo, G.

    2010-07-01

    The tufa record and hydrochemical characteristics of the River Piedra in the Monasterio de Piedra Natural Park (NE Spain) were studied for 6 years. The mean discharge of this river was 1.22 m3/s. The water was supersaturated with calcium carbonate. The HCO3 -, Ca2+ and TDIC concentrations decreased along the 0.5-km-long studied stretch, whereas the calcite SI showed no systematic downstream or seasonal variation over the same stretch. Several sedimentary subenvironments exist in which four broad types of tufa facies form: (1) Dense laminated tufa (stromatolites), (2) Dense to porous, massive tufa, (3) Porous, coarsely laminated tufa with bryophytes and algae, and (4) Dense, hard, laminated deposits in caves. The half-yearly period thickness and weight of sediment accumulated on 14 tablets installed in several subenvironments showed that the deposition rate was greater in fast flowing river areas and in stepped waterfalls, and lower in slow flowing or standing river areas and in spray and splash areas. Mechanical CO2 outgassing is the main factor controlling calcite precipitation on the river bed and in waterfalls, but this process does not explain the seasonal changes in depositional rates. The deposition rates showed a half-yearly period pattern recorded in all fluvial subenvironments persistent over time (5.26 mm, 0.86 g/cm2 in warm periods; 2.26 mm, 0.13 g/cm2 in cool periods). Mass balance calculations showed higher calcite mass values in warm (21.58 mg/L) than in cool (13.68 mg/L) periods. This biannual variation is mainly attributed to the seasonal differences in temperature that caused changes in inorganic calcite precipitation rate and in biomass and the correlative photosynthetic activity. Tufa sedimentation was therefore controlled by both physicochemical and biological processes. The results of this study may help test depositional rates and their environmental controls and thus assess the climatic and hydrological significance of ancient tufas in semi-arid conditions, in particular in the Quaternary.

  5. Spatial variation of present-day stress field and tectonic regime in Tunisia and surroundings from formal inversion of focal mechanisms: Geodynamic implications for central Mediterranean

    NASA Astrophysics Data System (ADS)

    Soumaya, A.; Ben Ayed, N.; Delvaux, D.; Ghanmi, M.; Zargouni, F.; Khayati Ammar, H.; Kadri, A.

    2015-12-01

    We compiled 123 focal mechanisms from various sources for Tunisia and adjacent regions up toSicily, to image the current stress field in the Maghrebides chain (from Tunisia to Sicily) and its foreland. Stressinversion of all the available data provides a first-order stress field with a N150°E horizontal compression(SHmax) and a transpressional tectonic regime, but the obtained stress tensor poorly fit to the data set.Weseparated them into regional subsets (boxes) in function of their geographical proximity, kinematicregime, homogeneity of kinematic orientations, and tectonic setting. Their respective inversion evidencessecond- and third-order spatial variations in tectonic regime and horizontal stress directions. The stressfield gradually changes from compression in the Maghrebides thrust belt to transpression and strike slipin the Atlassic and Pelagian foreland, respectively, where preexisting NW-SE to E-W deep faults systemare reactivated. This spatial variation of the sismotectonic stress field and tectonic regime is consistentwith the neotectonic stress field determined by others from fault slip data. The major Slab Transfer EdgePropagator faults (i.e., North-South Axis-Hammamet relay and Malte Escarpment), which laterally delimitthe subducting slabs, play an active role in second- and third-order lateral variations of the tectonicregime and stress field orientations over the Tunisian/Sicilian domain. The past and current tectonicdeformations and kinematics of the central Mediterranean are subordinately guided by the plateconvergence (i.e., Africa-Eurasia), controlled or influenced by lateral slab migration/segmentation andby deep dynamics such as lithosphere-mantle interaction.

  6. Discovery of Seafloor Massive Sulfides in an Andesite-Dacite Knoll Caldera off Present-Day Volcanic Front, Izu-Ogasawara Island Arc, Japan

    NASA Astrophysics Data System (ADS)

    Iizasa, K.; Asada, A.; Lee, S.; Mizuno, K.; Katase, F.; Kojima, M.; Kurozawa, T.

    2015-12-01

    We report the discovery of sulfide mounds with 20 to 30 m high sulfide chimneys in the Higashi-Aogashima hydrothermal field of a Quaternary andesite-dacite knoll caldera at the frontal arc side off Quaternary volcanic front, Izu-Ogasawara island arc, Japan. The discovery was carried out based on the systematic survey method of geological technique and a developed acoustic device using AUV. The knoll caldera 12 km east of Aogashima volcanic island is the size 10 km to 9 km of its rim and 820 m deep at its deepest caldera floor. According to the results of heavy mineral analysis for caldera sediments by a gravity corer, at least two areas were inferred to sites of potential hydrothermal activity associated with seafloor massive sulfides. After the precise acoustic survey using AUV there are many mound-like structures in the both inferred areas on the floor. Two major hydrothermal fields among them so far, which are a conical sulfide mound on the southeast flank of the central cone and a ridge-like mound on the inferred caldera boundary fault in the southeast, were confirmed based on sulfide samples recovered by a gravity corer during the next survey stage. One of them occurs at the water depth of 760 m to 770 m. It has active sulfide chimneys (ca. 20 m high) on the conical sulfide mound of about 40 m in diameter with 20 m high. Samples from the mound are composed of major sphalerite with moderate galena and barite, and minor chalcopyrite and pyrite. Another mound associated with chimneys at the water depth ranging from 740m to 770m on the southeast caldera boundary fault forms a small, east-west trend ridge-like shape. The ridge sizes more than 100 m long with 10 m wide. Chimneys are more than 30 m high. It is inferred that the mound is composed of major sphalerite and moderate barite based on samples cored at the margin of the mound. These results indicate that more than several sulfide mounds would be confirmed in the caldera floor by ROV surveys this September.

  7. High Lakes Project -- Impact of Climate Variability and High UV Flux on Lake Habitat: Implications for Early Mars and Present-Day Earth

    NASA Astrophysics Data System (ADS)

    Cabrol, N. A.; Grin, E. A.; Bebout, L.; Chong, G.; Demergasso, C.; Fleming, E.; Gaete, V.; Gibson, J.; Häder, D. P.; Mack, J.; Minkley, E.; Pinto, E.; Rose, K.; Ukstins Peate, I.; Tambley, C.; Williamson, C.; Wynne, J. J.

    2009-03-01

    HLP studies lakes between 4,200-6,000 m elevation in the Central Andes. Its primary objective is to understand the impact of increased environmental stress on lake habitats and their evolution during rapid climate change as an analogy to early Mars.

  8. Seismic and oceanographic evidence of present-day bottom-water dynamics in the Lousy Bank—Hatton Bank area, NE Atlantic

    NASA Astrophysics Data System (ADS)

    Due, L.; van Aken, H. M.; Boldreel, L. O.; Kuijpers, A.

    2006-11-01

    High-resolution multi-channel seismic records from the eastern margin of the Iceland Basin, Northeast Atlantic, are used to infer regional patterns of bottom water dynamics from seafloor morphology and distribution of the most recent geological units deposited along the margin. This information is combined with results from oceanographic and hydrodynamic measurements made in the area. The study area is located between Lousy Bank and Hatton Bank, where deep-water currents are forced around structural highs, leaving a complex pattern of topographically controlled sediment transport pathways. At the top and upper flank of Lousy Bank, George Bligh Bank and Hatton Bank topographic forcing leads to considerable acceleration of the northward flowing North Atlantic Current. At greater water depth, seismic facies indicative of bottom current action are found to be widespread. In addition, seafloor morphology displays moat features extending over large distances. The occurrence of these moats is confined to specific water depths in the range from 700-1400 m and from 1800 to 2200 m depth range. These depth ranges correspond to the basal depth stratum of the North Atlantic Current and the depth range of the Deep Northern Boundary Current, respectively. Geological evidence suggests maximum near-bottom current speed of about 0.5 m/s for these moat areas. Using oceanographic data we suggest that formation of the moats is not likely to be associated with the presence of a persistent high-speed contour current core, but probably originates from the occurrence of solibores and thus may be related to the internal wave field of the Iceland Basin possible linked to atmospheric pressure variation.

  9. The Lao Experience in Deploying Influenza A(H1N1)pdm09 Vaccine: Lessons Made Relevant in Preparing for Present Day Pandemic Threats.

    PubMed

    Xeuatvongsa, Anonh; Mirza, Sara; Winter, Christian; Feldon, Keith; Vongphrachanh, Phengta; Phonekeo, Darouny; Denny, Justin; Khanthamaly, Viengphone; Kounnavong, Bounheuang; Lylianou, Doualy; Phousavath, Sisouphane; Norasingh, Sisouveth; Boutta, Nao; Olsen, Sonja; Bresee, Joseph; Moen, Ann; Corwin, Andrew

    2015-01-01

    The Lao PDR, as did most countries of the Mekong Region, embarked on a pandemic vaccine initiative to counter the threat posed by influenza A(H1N1)pdm09. Overall, estimated vaccine coverage of the Lao population was 14%, with uptake in targeted health care workers and pregnant women 99% and 41%, respectively. Adverse Events Following Immunization accounted for only 6% of survey driven, reported vaccination experiences, with no severe consequences or deaths. Public acceptability of the vaccine campaign was high (98%). Challenges to vaccine deployment included: 1) no previous experience in fielding a seasonal influenza vaccine, 2) safety and efficacy concerns, and 3) late arrival of vaccine 10 months into the pandemic. The Lao success in surmounting these hurdles was in large measure attributed to the oversight assigned the National Immunization Program, and national sensitivities in responding to the avian influenza A(H5N1) crisis in the years leading up to the pandemic. The Lao "lessons learned" from pandemic vaccine deployment are made even more relevant four years on, given the many avian influenza strains circulating in the region, all with pandemic potential. PMID:25923779

  10. Dendritic Spines and Development: Towards a Unifying Model of Spinogenesis—A Present Day Review of Cajal's Histological Slides and Drawings

    PubMed Central

    García-López, Pablo; García-Marín, Virginia; Freire, Miguel

    2010-01-01

    Dendritic spines receive the majority of excitatory connections in the central nervous system, and, thus, they are key structures in the regulation of neural activity. Hence, the cellular and molecular mechanisms underlying their generation and plasticity, both during development and in adulthood, are a matter of fundamental and practical interest. Indeed, a better understanding of these mechanisms should provide clues to the development of novel clinical therapies. Here, we present original results obtained from high-quality images of Cajal's histological preparations, stored at the Cajal Museum (Instituto Cajal, CSIC), obtained using extended focus imaging, three-dimensional reconstruction, and rendering. Based on the data available in the literature regarding the formation of dendritic spines during development and our results, we propose a unifying model for dendritic spine development. PMID:21584262

  11. More than a century of bathymetric observations and present-day shallow sediment characterization in Belfast Bay, Maine, USA: implications for pockmark field longevity

    USGS Publications Warehouse

    Brothers, Laura L.; Kelley, Joseph T.; Belknap, Daniel F.; Barnhardt, Walter A.; Andrews, Brian D.; Maynard, Melissa Landon

    2011-01-01

    Mechanisms and timescales responsible for pockmark formation and maintenance remain uncertain, especially in areas lacking extensive thermogenic fluid deposits (e.g., previously glaciated estuaries). This study characterizes seafloor activity in the Belfast Bay, Maine nearshore pockmark field using (1) three swath bathymetry datasets collected between 1999 and 2008, complemented by analyses of shallow box-core samples for radionuclide activity and undrained shear strength, and (2) historical bathymetric data (report and smooth sheets from 1872, 1947, 1948). In addition, because repeat swath bathymetry surveys are an emerging data source, we present a selected literature review of recent studies using such datasets for seafloor change analysis. This study is the first to apply the method to a pockmark field, and characterizes macro-scale (>5 m) evolution of tens of square kilometers of highly irregular seafloor. Presence/absence analysis yielded no change in pockmark frequency or distribution over a 9-year period (1999–2008). In that time pockmarks did not detectably enlarge, truncate, elongate, or combine. Historical data indicate that pockmark chains already existed in the 19th century. Despite the lack of macroscopic changes in the field, near-bed undrained shear-strength values of less than 7 kPa and scattered downcore 137Cs signatures indicate a highly disturbed setting. Integrating these findings with independent geophysical and geochemical observations made in the pockmark field, it can be concluded that (1) large-scale sediment resuspension and dispersion related to pockmark formation and failure do not occur frequently within this field, and (2) pockmarks can persevere in a dynamic estuarine setting that exhibits minimal modern fluid venting. Although pockmarks are conventionally thought to be long-lived features maintained by a combination of fluid venting and minimal sediment accumulation, this suggests that other mechanisms may be equally active in maintaining such irregular seafloor morphology. One such mechanism could be upwelling within pockmarks induced by near-bed currents.

  12. More than a century of bathymetric observations and present-day shallow sediment characterization in Belfast Bay, Maine, USA: Implications for pockmark field longevity

    USGS Publications Warehouse

    Brothers, L.L.; Kelley, J.T.; Belknap, D.F.; Barnhardt, W.A.; Andrews, B.D.; Maynard, M.L.

    2011-01-01

    Mechanisms and timescales responsible for pockmark formation and maintenance remain uncertain, especially in areas lacking extensive thermogenic fluid deposits (e.g., previously glaciated estuaries). This study characterizes seafloor activity in the Belfast Bay, Maine nearshore pockmark field using (1) three swath bathymetry datasets collected between 1999 and 2008, complemented by analyses of shallow box-core samples for radionuclide activity and undrained shear strength, and (2) historical bathymetric data (report and smooth sheets from 1872, 1947, 1948). In addition, because repeat swath bathymetry surveys are an emerging data source, we present a selected literature review of recent studies using such datasets for seafloor change analysis. This study is the first to apply the method to a pockmark field, and characterizes macro-scale (>5 m) evolution of tens of square kilometers of highly irregular seafloor. Presence/absence analysis yielded no change in pockmark frequency or distribution over a 9-year period (1999-2008). In that time pockmarks did not detectably enlarge, truncate, elongate, or combine. Historical data indicate that pockmark chains already existed in the 19th century. Despite the lack of macroscopic changes in the field, near-bed undrained shear-strength values of less than 7 kPa and scattered downcore 137Cs signatures indicate a highly disturbed setting. Integrating these findings with independent geophysical and geochemical observations made in the pockmark field, it can be concluded that (1) large-scale sediment resuspension and dispersion related to pockmark formation and failure do not occur frequently within this field, and (2) pockmarks can persevere in a dynamic estuarine setting that exhibits minimal modern fluid venting. Although pockmarks are conventionally thought to be long-lived features maintained by a combination of fluid venting and minimal sediment accumulation, this suggests that other mechanisms may be equally active in maintaining such irregular seafloor morphology. One such mechanism could be upwelling within pockmarks induced by near-bed currents. ?? 2011 Springer-Verlag (outside the USA).

  13. Strong earthquake evolution and present-day earthquake hazard risk around the eastern boundary faults of Sichuan-Yunnan Rhombic Block

    NASA Astrophysics Data System (ADS)

    Cheng, J.; Xu, X.

    2011-12-01

    Based on the specific date of fault segmentation, characteristic earthquakes, and their empirical relationships, we calculated the parameters of the fault segments, such as length, width, magnitudes of characteristic earthquakes. Constrained by GPS velocity field, the slip rates of these fault segments in depth were inversed using the 3-D half-space dislocation model. As not all of the recurrence periods and co-seismic displacements of characteristic earthquakes were known, we selected the fault segments with these two parameters known and calculated the accumulation rate of average co-seismic displacement, which shows the faults' slip rate in seismogenic layer. Then, the slip rate in depth was compared with that in seismogenic layer, the relationship between them was obtained, and this relationship was used to get the recurrence periods and co-seismic displacements of all fault segments. After the studies above, we calculated post-seismic Coulomb stress changes of each fault segment produced by the earthquakes on these segments from AD 1700. Then, we used the relationship between the stress drop and the slip rate of the fault segments to show how many years of strain accumulation changed by the earthquakes. Adding the changed value of strain accumulation into the elapsed time of the characteristic earthquakes, we obtained the earthquake hazard degree of all the segments from the ratios between elapsed time and recurrence periods. At last, the BPT model was used to show the probability of earthquake hazard risks on the segments in the next 10 years and 30 years. Key words The eastern boundary faults of Sichuan-Yunnan rhombic block, characteristic earthquake, recurrence period, coulomb stress Earthquake hazard, BPT.

  14. Revealing a Child's Pathology: Physicians' Experiences

    ERIC Educational Resources Information Center

    Scelles, Regine; Aubert-Godard, Anne; Gargiulo, Marcela; Avant, Monique; Gortais, Jean

    2010-01-01

    In this study, 12 physicians and 12 care-givers were interviewed using semi-structured interviews. We explored physicians' experiences when they revealed a diagnosis. We also tried to understand which family members the physician was thinking of, with whom they identified themselves, and their first choice of the person to whom they prefer to…

  15. [Factor VII deficiency revealed by intracranial hemorrhage].

    PubMed

    Sfaihi Ben Mansour, L; Thabet, A; Aloulou, H; Turki, H; Chabchoub, I; Mhiri, F; Mnif, Z; Ben Ali, H; Kammoun, T; Hachicha, M

    2009-07-01

    Constitutional factor VII deficiency is a hereditary disease with recessive autosomic transmission. Its incidence is estimated to be 1/1,000,000 in the general population. We report a case of severe factor VII deficiency in infancy revealed by an intracranial hemorrhage in a 2-month-old infant. We describe the clinical, biological and therapeutic characteristics of this disease. PMID:19409767

  16. Eye Movements Reveal Dynamics of Task Control

    ERIC Educational Resources Information Center

    Mayr, Ulrich; Kuhns, David; Rieter, Miranda

    2013-01-01

    With the goal to determine the cognitive architecture that underlies flexible changes of control settings, we assessed within-trial and across-trial dynamics of attentional selection by tracking of eye movements in the context of a cued task-switching paradigm. Within-trial dynamics revealed a switch-induced, discrete delay in onset of…

  17. PULMONARY ARTERY ACCELERATED FLOW REVEALING HODGKIN'S LYMPHOMA.

    PubMed

    Ibrahim, Tony; Chehab, Ghassan; Saliba, Zakhia; Smayra, Tarek; Baz, Maria; Abdo, Lynn; Haddad, Fady; Abdel-Massih, Tony

    2016-01-01

    We present a case in which transthoracic echocardiography was the first diagnostic tool to suspect mediastinal Hodgkin's lymphoma by revealing a change in the hemodynamic of left pulmonary artery flow, and it was used as a follow-up method for monitoring treatment efficacy by demonstrating a normalization of pulmonary artery hemodynamics. PMID:27169170

  18. The cattle genome reveals its secrets

    PubMed Central

    Burt, David W

    2009-01-01

    The domesticated cow is the latest farm animal to have its genome sequenced and deciphered. The members of the Bovine Genome Consortium have published a series of papers on the assembly and what the sequence reveals so far about the biology of this ruminant and the consequences of its domestication. PMID:19439025

  19. [Skin metastases revealing a bronchial adenocarcinoma].

    PubMed

    Zemmez, Youssef; Zegmout, Adil; Hamama, Jalal; Bouhamidi, Ahmed; El Amraoui, Mohammed; El Azhari, Jaouad; Boui, Mohamed

    2016-01-01

    We report the case of bronchial carcinoma revealed by metastatic skin nodules on the scalp. This fairly common mode of discovery is often associated with poor prognosis. This study aims to underline the importance of directing the search for a primary lung cancer in cases of secondary skin involvement. PMID:27583066

  20. Septic sacroiliitis revealing an infectious endocarditis

    PubMed Central

    Mahfoudhi, Madiha; Hariz, Anis; Turki, Sami; Kheder, Adel

    2014-01-01

    We report the case of a 43-year-old man admitted for right hip ache and fever. Physical examination revealed a fever, an ache at the manipulation of the sacroiliac joint and a limitation of abduction and external rotation of the right hip. There was no murmur in cardiac auscultation. No anomaly was found at the conventional radiographs of the sacroiliac joint, while the pelvic MRI confirmed a right sacroiliitis. A sacroiliac puncture with a study of synovial fluid demonstrated the presence of Streptococcus viridans. The blood culture revealed the same germ. Transthoracic and transoesophageal echocardiography confirmed infectious endocarditis with vegetation in the mitral valve. He received penicillin G and gentamicin relayed by pristinamycin because of an allergy to penicillin G with a total duration of treatment of 40 days. His symptoms and the laboratory and radiological tests abnormalities resolved totally with no recurrence. PMID:25123569

  1. Orbital tumor revealing a systemic sarcoidosis.

    PubMed

    Hannanachi Sassi, Samia; Dhouib, Rim; Kanchal, Fatma; Doghri, Raoudha; Boujelbene, Nadia; Bouguila, Hedi; Mrad, Karima

    2015-01-01

    Ocular involvement is seen in approximately 25% of patients with sarcoidosis. Uveitis is the most common ocular manifestation, but sarcoidosis may involve any part of the eye. Orbital manifestations of sarcoidosis are uncommon with few series in the literature. A 65-year-old woman presented with redness of the right eye and painless, unilateral eyelid swelling. Orbital scanning revealed mass infiltrating the soft tissue of the inferior right orbital quadrant. Biopsy results showed nodular, noncaseating granulomas consistent with sarcoidosis. The complete systemic workup revealed systemic manifestations of sarcoidosis at the time of examination with hilar and mediastinal lymphadenopathies noted on CT scan. The orbital surgical treatment was followed by systemic prednisone therapy with good response. Although rare, orbital sarcoidosis must be considered in the evaluation of orbital tumors in elderly patients. A search for systemic findings should be undertaken and appropriate therapy should be instituted. PMID:25796029

  2. Mediastinal Mature Teratoma Revealed by Empyema.

    PubMed

    Raoufi, Mohammed; Herrak, Laila; Benali, Anas; Achaachi, Leila; El Ftouh, Mustapha; Bellarbi, Salma; Tilfine, Charaf; Taouarsa, Firdaous

    2016-01-01

    Teratomas are germ cell tumors, manifested with a great variety of clinical features; the most common extragonadal site is the anterior mediastinum. In this case, we report the patient with a large mature mediastinal teratoma with several components of ectodermal and endothermal epithelium. A 24-year-old female patient presented with history of persistent chest pain and progressively aggravating dyspnea for the previous 3 months. A chest X-ray showed a large opacity of the entire left hemithorax. Transcutaneous needle aspiration revealed a purulent fluid. The tube thoracostomy was introduced and the effusion was evacuated. Some weeks later, patient was seen in emergency for persistent cough and lateral chest pain. CT scan revealed a mass of the left hemithorax. The mass showed heterogeneous density, without compressing mediastinum great vessels and left hilar structures. Lipase value was elevated in needle aspiration. The patient underwent a total resection of the mediastinum mass via a left posterolateral thoracotomy. Microscopy revealed a mature teratoma with cystic structures. The patient subsequently made a full recovery. This case provide benign mediastinal teratoma with total atelectasis of left lung and elevated lipase value in needle transcutaneous aspiration; this event is explained by pancreatic component in the cystic tumor. Total removal of the tumor is adequate treatment for this type of teratoma and the prognosis is excellent. PMID:27144046

  3. Mediastinal Mature Teratoma Revealed by Empyema

    PubMed Central

    Raoufi, Mohammed; Herrak, Laila; Benali, Anas; Achaachi, Leila; El Ftouh, Mustapha; Bellarbi, Salma; Tilfine, Charaf; Taouarsa, Firdaous

    2016-01-01

    Teratomas are germ cell tumors, manifested with a great variety of clinical features; the most common extragonadal site is the anterior mediastinum. In this case, we report the patient with a large mature mediastinal teratoma with several components of ectodermal and endothermal epithelium. A 24-year-old female patient presented with history of persistent chest pain and progressively aggravating dyspnea for the previous 3 months. A chest X-ray showed a large opacity of the entire left hemithorax. Transcutaneous needle aspiration revealed a purulent fluid. The tube thoracostomy was introduced and the effusion was evacuated. Some weeks later, patient was seen in emergency for persistent cough and lateral chest pain. CT scan revealed a mass of the left hemithorax. The mass showed heterogeneous density, without compressing mediastinum great vessels and left hilar structures. Lipase value was elevated in needle aspiration. The patient underwent a total resection of the mediastinum mass via a left posterolateral thoracotomy. Microscopy revealed a mature teratoma with cystic structures. The patient subsequently made a full recovery. This case provide benign mediastinal teratoma with total atelectasis of left lung and elevated lipase value in needle transcutaneous aspiration; this event is explained by pancreatic component in the cystic tumor. Total removal of the tumor is adequate treatment for this type of teratoma and the prognosis is excellent. PMID:27144046

  4. Contribution of Common Genetic Variants to Obesity and Obesity-Related Traits in Mexican Children and Adults

    PubMed Central

    Villalobos-Comparán, Marisela; Villarreal-Molina, Teresa; Romero-Hidalgo, Sandra; López-Contreras, Blanca; Gutiérrez-Vidal, Roxana; Vega-Badillo, Joel; Jacobo-Albavera, Leonor; Posadas-Romeros, Carlos; Canizalez-Román, Adrián; Río-Navarro, Blanca Del; Campos-Pérez, Francisco; Acuña-Alonzo, Victor; Aguilar-Salinas, Carlos; Canizales-Quinteros, Samuel

    2013-01-01

    Background Several studies have identified multiple obesity-associated loci mainly in European populations. However, their contribution to obesity in other ethnicities such as Mexicans is largely unknown. The aim of this study was to examine 26 obesity-associated single-nucleotide polymorphisms (SNP) in a sample of Mexican mestizos. Methods 9 SNPs in biological candidate genes showing replications (PPARG, ADRB3, ADRB2, LEPR, GNB3, UCP3, ADIPOQ, UCP2, and NR3C1), and 17 SNPs in or near genes associated with obesity in first, second and third wave GWAS (INSIG2, FTO, MC4R, TMEM18, FAIM2/BCDIN3, BDNF, SH2B1, GNPDA2, NEGR1, KCTD15, SEC16B/RASAL2, NPC1, SFRF10/ETV5, MAF, PRL, MTCH2, and PTER) were genotyped in 1,156 unrelated Mexican-Mestizos including 683 cases (441 obese class I/II and 242 obese class III) and 473 normal-weight controls. In a second stage we selected 12 of the SNPs showing nominal associations with obesity, to seek associations with quantitative obesity-related traits in 3 cohorts including 1,218 Mexican Mestizo children, 945 Mexican Mestizo adults, and 543 Indigenous Mexican adults. Results After adjusting for age, sex and admixture, significant associations with obesity were found for 6 genes in the case-control study (ADIPOQ, FTO, TMEM18, INSIG2, FAIM2/BCDIN3 and BDNF). In addition, SH2B1 was associated only with class I/II obesity and MC4R only with class III obesity. SNPs located at or near FAIM2/BCDIN3, TMEM18, INSIG2, GNPDA2 and SEC16B/RASAL2 were significantly associated with BMI and/or WC in the combined analysis of Mexican-mestizo children and adults, and FTO locus was significantly associated with increased BMI in Indigenous Mexican populations. Conclusions Our findings replicate the association of 8 obesity-related SNPs with obesity risk in Mexican adults, and confirm the role of some of these SNPs in BMI in Mexican adults and children. PMID:23950976

  5. Middle atmosphere composition revealed by satellite observations

    NASA Technical Reports Server (NTRS)

    Russell, J. M., III; Solomon, S.; Mccormick, M. P.; Miller, A. J.; Barnett, J. J.; Jones, R. L.; Rusch, D. W.

    1986-01-01

    A series of plots that describe the state of the stratosphere and to some degree, the mesosphere as revealed by satellite observations are shown. The pertinent instrument features, spatial and temporal coverage, and details of accuracy and precision for the experiments providing the data were described. The main features of zonal mean cross sections and polar stereographic projections were noted and intercomparisons were discussed where a parameter was measured by more than one experiment. The main purpose was to collect the available data in one place and provide enough inforamation on limitations or cautions about the data so that they could be used in model comparisons and science studies.

  6. Trench Reveals Two Faces of Soils

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This approximate true-color image mosaic from the panoramic camera on the Mars Exploration Rover Opportunity shows a trench dug by the rover in the vicinity of the 'Anatolia' region. Two imprints from the rover's Mossbauer spectrometer instrument were left in the exposed soils. Detailed comparisons between soils exposed at the surface and those found at depth reveal that surface soils have higher levels of hematite while subsurface soils show fine particles derived from basalt. The trench is approximately 11 centimeters deep. This image was taken on sol 81 with the panoramic camera's 430-, 530- and 750-nanometer filters.

  7. Reveal quantum correlation in complementary bases

    PubMed Central

    Wu, Shengjun; Ma, Zhihao; Chen, Zhihua; Yu, Sixia

    2014-01-01

    An essential feature of genuine quantum correlation is the simultaneous existence of correlation in complementary bases. We reveal this feature of quantum correlation by defining measures based on invariance under a basis change. For a bipartite quantum state, the classical correlation is the maximal correlation present in a certain optimum basis, while the quantum correlation is characterized as a series of residual correlations in the mutually unbiased bases. Compared with other approaches to quantify quantum correlation, our approach gives information-theoretical measures that directly reflect the essential feature of quantum correlation. PMID:24503595

  8. Cerebral venous thrombosis revealing an ulcerative colitis

    PubMed Central

    Taous, Abdellah; Berri, Maha Aït; Lamsiah, Taoufik; Zainoun, Brahim; Ziadi, Tarik; Rouimi, Abdelhadi

    2016-01-01

    Cerebral venous thrombosis (CVT) has been reported as an uncommon and devastating complication of ulcerative colitis (UC), with an annual incidence varying between 0,5 to 6,7%. It is suspected to be a consequence of the hypercoagulable state occurring during disease relapse. We report a case of 22-year-old female patient presenting with CVT revealing an UC. Our case raises the awareness among health professionals about the inflammatory bowel diseases (IBD) as a rare etiology of CVT, and signifies the importance of considering antithrombotic prophylaxis in all hospitalised IBD patients, especially those with active disease. PMID:27279947

  9. Infections Revealing Complement Deficiency in Adults

    PubMed Central

    Audemard-Verger, A.; Descloux, E.; Ponard, D.; Deroux, A.; Fantin, B.; Fieschi, C.; John, M.; Bouldouyre, A.; Karkowsi, L.; Moulis, G.; Auvinet, H.; Valla, F.; Lechiche, C.; Davido, B.; Martinot, M.; Biron, C.; Lucht, F.; Asseray, N.; Froissart, A.; Buzelé, R.; Perlat, A.; Boutboul, D.; Fremeaux-Bacchi, V.; Isnard, S.; Bienvenu, B.

    2016-01-01

    Abstract Complement system is a part of innate immunity, its main function is to protect human from bacterial infection. As genetic disorders, complement deficiencies are often diagnosed in pediatric population. However, complement deficiencies can also be revealed in adults but have been poorly investigated. Herein, we describe a case series of infections revealing complement deficiency in adults to study clinical spectrum and management of complement deficiencies. A nationwide retrospective study was conducted in French university and general hospitals in departments of internal medicine, infectious diseases enrolling patients older than 15 years old who had presented at least one infection leading to a complement deficiency diagnosis. Forty-one patients included between 2002 and 2015 in 19 different departments were enrolled in this study. The male-to-female ratio was 1.3 and the mean age at diagnosis was 28 ± 14 (15–67) years. The main clinical feature was Neisseria meningitidis meningitis 75% (n = 31/41) often involving rare serotype: Y (n = 9) and W 135 (n = 7). The main complement deficiency observed was the common final pathway deficiency 83% (n = 34/41). Half of the cohort displayed severe sepsis or septic shock at diagnosis (n = 22/41) but no patient died. No patient had family history of complement deficiency. The mean follow-up was 1.15 ± 1.95 (0.1–10) years. Half of the patients had already suffered from at least one infection before diagnosis of complement deficiency: meningitis (n = 13), pneumonia (n = 4), fulminans purpura (n = 1), or recurrent otitis (n = 1). Near one-third (n = 10/39) had received prophylactic antibiotics (cotrimoxazole or penicillin) after diagnosis of complement deficiency. The vaccination coverage rate, at the end of the follow-up, for N meningitidis, Streptococcus pneumonia, and Haemophilius influenzae were, respectively, 90% (n = 33/37), 47% (n = 17/36), and 35

  10. What Eye Movements Reveal about Deaf Readers

    PubMed Central

    Bélanger, Nathalie N.; Rayner, Keith

    2014-01-01

    Levels of illiteracy in the deaf populations around the world have been extremely high for decades and much higher than the illiteracy levels found in the general population. Research has mostly focused on deaf readers’ difficulties rather than on their strengths, which can then inform reading education. Deaf readers are a unique population. They process language and the world surrounding them mostly via the visual channel and this greatly affects how they read or might learn to read. The study of eye movements in reading provides highly sophisticated information about how words and sentences are processed and our research with deaf readers reveals the importance of their uniqueness. PMID:26594098

  11. Apocalypto: revealing lost text with XMT

    NASA Astrophysics Data System (ADS)

    Mills, David; Davis, Graham R.; Lai, Yu-kun; Rosin, Paul

    2014-09-01

    "Can brute-force high-contrast tomography techniques and image processing techniques retrieve textual content from damaged heritage materials?" The Dental Institute at Queen Mary University of London (QMUL) is the leading centre for very high contrast X-Ray Microtomography imaging. The Apocalypto Project is our collaboration with the heritage community and experts in Computer Vision systems in the Computer Science Department at Cardiff University. This collaboration has developed techniques and a workflow that allows us to reveal textual content from moisture-damaged parchment rolls. This article will also present some initial results from burned and heat shrunken parchment rolls, an insect damaged Mamluk cap and a birch bark roll.

  12. Saturn's secrets revealed - A special report

    NASA Astrophysics Data System (ADS)

    Sutton, C.

    1980-11-01

    Scientific results of the encounter of Voyager 1 with Saturn are reported. Instruments on the Voyager spacecraft, which was launched on September 5, 1977 and flew within 124,200 km of the Saturn cloud tops on November 12, 1980, revealed the presence of several hundred rings within the six visible from earth, as well as eccentric rings, braiding and clumps within the narrow F ring, and spoke-like structures in the B ring. During its flight beneath the ring plane, Voyager 1 also discovered that the rings extend toward the visible surface of the cloud tops, and are composed of ice chunks or silicate with an icy coating about a meter in diameter. Observations of Titan revealed the satellite to have a dense atmosphere, composed primarily of molecular nitrogen, with as many as three layers of haze above the cloud tops. Three additional moons of Saturn were discovered apparently focusing ring particles, and the moon Janus, discovered from earth in 1966, was shown to be actually two moons. Close approaches to other Saturn satellites show Mimas, Tethys, Dione and Rhea to be heavily cratered, icy bodies, some with features indicating they had been struck by objects almost large enough to shatter them. Surface features on Saturn, which is covered by a deep layer of haze, and the details of the Saturn magnetosphere have also been observed.

  13. Exertional rhabdomyolysis and exercise intolerance revealing dystrophinopathies.

    PubMed

    Figarella-Branger, D; Baeta Machado, A M; Putzu, G A; Malzac, P; Voelckel, M A; Pellissier, J F

    1997-07-01

    Exercise intolerance associated with myalgias, muscle cramps or myoglobinuria may be associated with a dystrophinopathy. A search for abnormal dystrophin expression (using immunohistochemistry, immunoblot and DNA analysis) was carried out in a series of 15 patients. They were selected because they presented exercise intolerance, negative biochemical tests (lipid, glycogen and mitochondrial metabolism) and abnormal immunohistochemistry with at least one anti-dystrophin antibody (anti-Dys 1, rod domain; anti-Dys 2, C terminus; anti-Dys 3, N terminus). Lack of anti-Dys 1 immunoreactivity was seen in three patients and abnormal immunoreactivity with all three anti-dystrophin antibodies in two. Immunoblot confirmed the dystrophinopathy in these five patients only, and multiplex polymerase chain reaction DNA analysis revealed a deletion in the dystrophin gene in two of these patients, affecting the proximal part of the rod domain in one and the distal part of this domain in the other. The clinical, biological and histopathological features of the five patients reported here, together with the previous cases reported in the literature, are described and reveal that exercise intolerance associated with dystrophinopathy displays characteristic clinical, biological and immunohistochemical features and defines a new dystrophinopathy phenotype. The absence of staining in the rod domain provides a secure diagnosis of this syndrome. Dystrophinopathy is one etiology of idiopathic myoglobinuria, requiring genetic counseling. PMID:9224530

  14. Interior Evolution of Ceres Revealed by Dawn

    NASA Astrophysics Data System (ADS)

    Raymond, Carol A.; Park, Ryan S.; Konopliv, Alex S.; Bland, Michael T.; Marchi, Simone; Castillo-Rogez, Julie C.; McCord, Thomas B.; Jaumann, Ralf; Russell, Christopher T.; Prettyman, Thomas H.

    2015-11-01

    Dawn's exploration of Ceres has revealed its geophysical characteristics, informing the processes that have shaped it. Dawn has determined the average diameter of Ceres to be 940 km, smaller than the previously estimated 975 km [1]. This implies a density of 2160 kg/m3, indicating that Ceres is less differentiated than predicted [2]. The low-degree gravity field is consistent with the body being in hydrostatic equilibrium and the magnitude of J2 implies some central condensation. Ceres' entire surface is cratered, implying the lack of a thick (10's of km) water ice layer at the surface. Variability in Ceres' crater morphology indicates that the near-surface layer has variable strength and rheology, likely due to heterogeneity in the near-surface mixture of rock, ice and salt. The lack of a number of expected large impact basins on Ceres can be interpreted to be the result of viscous relaxation, resurfacing or a combination of both. These data provide insights into Ceres' thermal evolution and mechanical properties, which appear to be unique to this warm, icy body.[1] Thomas, P. C., et al., Differentiation of the asteroid Ceres as revealed by its shape, Nature, 437, 224-226, 2005; [2] McCord et al., Ceres: Its Origin, Evolution and Structure and Dawn's Potential Contribution, Space Sci Rev DOI 10.1007/s11214-010-9729-9, 2011.

  15. Asymmetrical magnetic fabrics in the Egersund doleritic dike swarm (SW Norway) reveal sinistral oblique rifting before the opening of the Iapetus

    NASA Astrophysics Data System (ADS)

    Montalbano, Salvatrice; Diot, Hervé; Bolle, Olivier

    2016-04-01

    The 616 ± 3 Ma (Ediacaran) Egersund doleritic dike swarm cuts across the Rogaland anorthosite province and its granulitic country rocks, in SW Norway. The structure of eight out of eleven main dikes of the swarm was investigated using the anisotropy of magnetic susceptibility (AMS) technique. Thermomagnetic data and values of the bulk magnetic susceptibility reveal a magnetic mineralogy dominated by Ti-poor titanomagnetite. Magnetic fabric and global petrofabric are coaxial, except in sites strongly affected by hydrothermal alteration, as demonstrated through image analysis. Asymmetrical dispositions of the magnetic foliation and lineation support the existence of a syn-emplacement, sinistral strike-slip shearing resolved on dike walls. Such asymmetrical fabrics are attributed to a transtension tectonic regime, in a context of oblique extension during the continental rifting phase which preceded the opening of the Iapetus Ocean along the SW margin (present-day orientation) of Baltica.

  16. Semantic priming revealed by mouse movement trajectories.

    PubMed

    Xiao, Kunchen; Yamauchi, Takashi

    2014-07-01

    Congruency effects are taken as evidence that semantic information can be processed automatically. However, these effects are often weak, and the straightforward association between primes and targets can exaggerate congruency effects. To address these problems, a mouse movement method is applied to scrutinize congruency effects. In one experiment, participants judged whether two numbers were the same ("3\\3") or different ("3\\5"), preceded by briefly presented pictures with either positive or negative connotations. Participants indicated their responses by clicking a "Same" or "Different" button on the computer screen, while their cursor trajectories were recorded for each trial. The trajectory data revealed greater deviation to unselected buttons in incongruent trials (e.g., "3\\5" preceded by a green traffic light picture). This effect was influenced by the type of responses but not by prime durations. We suggest that the mouse movement method can complement the reaction time to study masked semantic priming. PMID:24797040

  17. Neutron Imaging Reveals Internal Plant Hydraulic Dynamics

    SciTech Connect

    Warren, Jeffrey; Bilheux, Hassina Z; Kang, Misun; Voisin, Sophie; Cheng, Chu-Lin; Horita, Jusuke; Perfect, Edmund

    2013-01-01

    Many terrestrial ecosystem processes are constrained by water availability and transport within the soil. Knowledge of plant water fluxes is thus critical for assessing mechanistic processes linked to biogeochemical cycles, yet resolution of root structure and xylem water transport dynamics has been a particularly daunting task for the ecologist. Through neutron imaging, we demonstrate the ability to non-invasively monitor individual root functionality and water fluxes within Zea mays L. (maize) and Panicum virgatum L. (switchgrass) seedlings growing in a sandy medium. Root structure and growth were readily imaged by neutron radiography and neutron computed tomography. Seedlings were irrigated with water or deuterium oxide and imaged through time as a growth lamp was cycled on to alter leaf demand for water. Sub-millimeter scale resolution reveals timing and magnitudes of root water uptake, redistribution within the roots, and root-shoot hydraulic linkages, relationships not well characterized by other techniques.

  18. Open chromatin reveals the functional maize genome

    PubMed Central

    Rodgers-Melnick, Eli; Vera, Daniel L.; Bass, Hank W.

    2016-01-01

    Cellular processes mediated through nuclear DNA must contend with chromatin. Chromatin structural assays can efficiently integrate information across diverse regulatory elements, revealing the functional noncoding genome. In this study, we use a differential nuclease sensitivity assay based on micrococcal nuclease (MNase) digestion to discover open chromatin regions in the maize genome. We find that maize MNase-hypersensitive (MNase HS) regions localize around active genes and within recombination hotspots, focusing biased gene conversion at their flanks. Although MNase HS regions map to less than 1% of the genome, they consistently explain a remarkably large amount (∼40%) of heritable phenotypic variance in diverse complex traits. MNase HS regions are therefore on par with coding sequences as annotations that demarcate the functional parts of the maize genome. These results imply that less than 3% of the maize genome (coding and MNase HS regions) may give rise to the overwhelming majority of phenotypic variation, greatly narrowing the scope of the functional genome. PMID:27185945

  19. Social patterns revealed through random matrix theory

    NASA Astrophysics Data System (ADS)

    Sarkar, Camellia; Jalan, Sarika

    2014-11-01

    Despite the tremendous advancements in the field of network theory, very few studies have taken weights in the interactions into consideration that emerge naturally in all real-world systems. Using random matrix analysis of a weighted social network, we demonstrate the profound impact of weights in interactions on emerging structural properties. The analysis reveals that randomness existing in particular time frame affects the decisions of individuals rendering them more freedom of choice in situations of financial security. While the structural organization of networks remains the same throughout all datasets, random matrix theory provides insight into the interaction pattern of individuals of the society in situations of crisis. It has also been contemplated that individual accountability in terms of weighted interactions remains as a key to success unless segregation of tasks comes into play.

  20. Open chromatin reveals the functional maize genome.

    PubMed

    Rodgers-Melnick, Eli; Vera, Daniel L; Bass, Hank W; Buckler, Edward S

    2016-05-31

    Cellular processes mediated through nuclear DNA must contend with chromatin. Chromatin structural assays can efficiently integrate information across diverse regulatory elements, revealing the functional noncoding genome. In this study, we use a differential nuclease sensitivity assay based on micrococcal nuclease (MNase) digestion to discover open chromatin regions in the maize genome. We find that maize MNase-hypersensitive (MNase HS) regions localize around active genes and within recombination hotspots, focusing biased gene conversion at their flanks. Although MNase HS regions map to less than 1% of the genome, they consistently explain a remarkably large amount (∼40%) of heritable phenotypic variance in diverse complex traits. MNase HS regions are therefore on par with coding sequences as annotations that demarcate the functional parts of the maize genome. These results imply that less than 3% of the maize genome (coding and MNase HS regions) may give rise to the overwhelming majority of phenotypic variation, greatly narrowing the scope of the functional genome. PMID:27185945

  1. Revealing effective classifiers through network comparison

    NASA Astrophysics Data System (ADS)

    Gallos, Lazaros K.; Fefferman, Nina H.

    2014-11-01

    The ability to compare complex systems can provide new insight into the fundamental nature of the processes captured, in ways that are otherwise inaccessible to observation. Here, we introduce the n-tangle method to directly compare two networks for structural similarity, based on the distribution of edge density in network subgraphs. We demonstrate that this method can efficiently introduce comparative analysis into network science and opens the road for many new applications. For example, we show how the construction of a “phylogenetic tree” across animal taxa according to their social structure can reveal commonalities in the behavioral ecology of the populations, or how students create similar networks according to the University size. Our method can be expanded to study many additional properties, such as network classification, changes during time evolution, convergence of growth models, and detection of structural changes during damage.

  2. Metabolomics reveals metabolic biomarkers of Crohn's disease

    SciTech Connect

    Jansson, J.K.; Willing, B.; Lucio, M.; Fekete, A.; Dicksved, J.; Halfvarson, J.; Tysk, C.; Schmitt-Kopplin, P.

    2009-06-01

    The causes and etiology of Crohn's disease (CD) are currently unknown although both host genetics and environmental factors play a role. Here we used non-targeted metabolic profiling to determine the contribution of metabolites produced by the gut microbiota towards disease status of the host. Ion Cyclotron Resonance Fourier Transform Mass Spectrometry (ICR-FT/MS) was used to discern the masses of thousands of metabolites in fecal samples collected from 17 identical twin pairs, including healthy individuals and those with CD. Pathways with differentiating metabolites included those involved in the metabolism and or synthesis of amino acids, fatty acids, bile acids and arachidonic acid. Several metabolites were positively or negatively correlated to the disease phenotype and to specific microbes previously characterized in the same samples. Our data reveal novel differentiating metabolites for CD that may provide diagnostic biomarkers and/or monitoring tools as well as insight into potential targets for disease therapy and prevention.

  3. Chain networking revealed by molecular dynamics simulation

    NASA Astrophysics Data System (ADS)

    Zheng, Yexin; Tsige, Mesfin; Wang, Shi-Qing

    Based on Kremer-Grest model for entangled polymer melts, we demonstrate how the response of a polymer glass depends critically on the chain length. After quenching two melts of very different chain lengths (350 beads per chain and 30 beads per chain) into deeply glassy states, we subject them to uniaxial extension. Our MD simulations show that the glass of long chains undergoes stable necking after yielding whereas the system of short chains is unable to neck and breaks up after strain localization. During ductile extension of the polymer glass made of long chain significant chain tension builds up in the load-bearing strands (LBSs). Further analysis is expected to reveal evidence of activation of the primary structure during post-yield extension. These results lend support to the recent molecular model 1 and are the simulations to demonstrate the role of chain networking. This work is supported, in part, by a NSF Grant (DMR-EAGER-1444859)

  4. Licking Microstructure Reveals Rapid Attenuation of Neophobia

    PubMed Central

    Monk, Kevin J.; Rubin, Benjamin D.

    2014-01-01

    Many animals hesitate when initially consuming a novel food and increase their consumption of that food between the first and second sessions of access—a process termed attenuation of neophobia (AN). AN has received attention as a model of learning and memory; it has been suggested that plasticity resulting from an association of the novel tastant with “safe outcome” results in a change in the neural response to the tastant during the second session, such that consumption increases. Most studies have reported that AN emerges only an hour or more after the end of the first exposure to the tastant, consistent with what is known of learning-related plasticity. But these studies have typically measured consumption, rather than real-time behavior, and thus the possibility exists that a more rapidly developing AN remains to be discovered. Here, we tested this possibility, examining both consumption and individual lick times in a novel variant of a brief-access task (BAT). When quantified in terms of consumption, data from the BAT accorded well with the results of a classic one-bottle task—both revealed neophobia/AN specific to higher concentrations (for instance, 28mM) of saccharin. An analysis of licking microstructure, however, additionally revealed a real-time correlate of neophobia—an explicit tendency, similarly specific for 28-mM saccharin, to cut short the initial bout of licks in a single trial (compared with water). This relative hesitancy (i.e., the shortness of the first lick bout to 28-mM saccharin compared with water) that constitutes neophobia not only disappeared between sessions but also gradually declined in magnitude across session 1. These data demonstrate that the BAT accurately measures AN, and that aspects of AN—and the processes underlying familiarization—begin within minutes of the very first taste. PMID:24363269

  5. Ceres Revealed in a Grain of Salt

    NASA Technical Reports Server (NTRS)

    Zolensky, M. E.; Bodnar, R. J.; Fries, M.; Chan, Q. H.-S.; Kebukawa, Y.; Mikouchi, T.; Hagiya, K.; Komatsu, M.; Ohsumi, K.; Steele, A.

    2016-01-01

    Introduction: Zag and Monahans (1998) are H chondrite regolith breccias containing 4.5 giga-year-old halite crystals which contain abundant inclusions of aqueous fluids, solids and organics. These all originated on a cryo-volcanically-active C class asteroid, probably 1 Ceres; the halite was transported to the regolith of the H chondrite parent asteroid, potentially 6 Hebe. Detailed analysis of these solids will thus potentially reveal the mineralogy of Ceres. Mineralogy of solids in the Monahans Halite Solid grains are present in the halites, which were entrained within the mother brines during eruption, including material from the interior and surface of the erupting body. The solids include abundant, widely variable organics that could not have been significantly heated (which would have resulted in the loss of fluids from the halite). Our analyses by Raman microprobe, SEM/EDX, synchrotron X-ray diffraction, UPLC-FD/QToF-MS, C-XANES and TEM reveal that these trapped grains include macromolecular carbon (MMC) similar in structure to CV3 chondrite matrix carbon, aliphatic carbon compounds, olivine (Fo99-59), high- and low-Ca pyroxene, feldspars, phyllosilicates, magnetite, sulfides, metal, lepidocrocite, carbonates, diamond, apatite and zeolites. Conclusions: The halite in Monahans and Zag derive from a water and carbon-rich object that was cryo-volcanically active in the early solar system, probably Ceres. The Dawn spacecraft found that Ceres includes C chondrite materials. Our samples include both protolith and aqueously-altered samples of the body, permitting understanding of alteration conditions. Whatever the halite parent body, it was rich in a wide variety of organics and warm, liquid water at the solar system's dawn.

  6. Active fault creep variations at Chihshang, Taiwan, revealed by creep meter monitoring, 1998-2001

    NASA Astrophysics Data System (ADS)

    Lee, Jian-Cheng; Angelier, Jacques; Chu, Hao-Tsu; Hu, Jyr-Ching; Jeng, Fu-Shu; Rau, Ruey-Juin

    2003-11-01

    The daily creep meter data recorded at Chihshang in 1998-2001 are presented. The Chihshang creep meter experiment was set up across the Chihshang thrust fault, the most active segment of the Longitudinal Valley Fault, which is the present-day plate suture between the Eurasian and the Philippine Sea plates in eastern Taiwan. Near-continuous data recording at two sites revealed different surface fault motions yet similar annual shortening rates: 16.2 mm at the Tapo site (comprising two connected creep meters) and 15.0 mm at the Chinyuan site (three creep meters straddling parallel fault branches). Four of the five creep meters showed a seasonal variation, with the fault moving steadily during the rainy season from April to October, and remaining quiescent during the rest of the year. The only exception was recorded by the creep meter located on a mélange-composed hillslope, where local gravitational landsliding played an additional role other than tectonic faulting. Through comparison with daily precipitation data, we inferred that moderate rainfall suffices to trigger or facilitate slippage on the surface fault, during the transition period of the dry/wet season. During the observation period from 1998 to 2001, the subsurface seismicity exhibited clusters of microearthquakes on the Chihshang Fault at depths of 10-25 km. Recurrent earthquakes occurred regardless of whether the season was wet or dry, indicating that the stress relaxation associated with