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Sample records for noncalcifying haptophytes explains

  1. Extreme diversity in noncalcifying haptophytes explains a major pigment paradox in open oceans

    Science.gov (United States)

    Liu, Hui; Probert, Ian; Uitz, Julia; Claustre, Hervé; Aris-Brosou, Stéphane; Frada, Miguel; Not, Fabrice; de Vargas, Colomban

    2009-01-01

    The current paradigm holds that cyanobacteria, which evolved oxygenic photosynthesis more than 2 billion years ago, are still the major light harvesters driving primary productivity in open oceans. Here we show that tiny unicellular eukaryotes belonging to the photosynthetic lineage of the Haptophyta are dramatically diverse and ecologically dominant in the planktonic photic realm. The use of Haptophyta-specific primers and PCR conditions adapted for GC-rich genomes circumvented biases inherent in classical genetic approaches to exploring environmental eukaryotic biodiversity and led to the discovery of hundreds of unique haptophyte taxa in 5 clone libraries from subpolar and subtropical oceanic waters. Phylogenetic analyses suggest that this diversity emerged in Paleozoic oceans, thrived and diversified in the permanently oxygenated Mesozoic Panthalassa, and currently comprises thousands of ribotypic species, belonging primarily to low-abundance and ancient lineages of the “rare biosphere.” This extreme biodiversity coincides with the pervasive presence in the photic zone of the world ocean of 19′-hexanoyloxyfucoxanthin (19-Hex), an accessory photosynthetic pigment found exclusively in chloroplasts of haptophyte origin. Our new estimates of depth-integrated relative abundance of 19-Hex indicate that haptophytes dominate the chlorophyll a-normalized phytoplankton standing stock in modern oceans. Their ecologic and evolutionary success, arguably based on mixotrophy, may have significantly impacted the oceanic carbon pump. These results add to the growing evidence that the evolution of complex microbial eukaryotic cells is a critical force in the functioning of the biosphere. PMID:19622724

  2. Phylogenomic analysis of Emiliania huxleyi provides evidence for haptophyte-stramenopile association and a chimeric haptophyte nuclear genome.

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    Miller, John J; Delwiche, Charles F

    2015-06-01

    Emiliania huxleyi is a haptophyte alga of uncertain phylogenetic affinity containing a secondarily derived, chlorophyll c containing plastid. We sought to characterize its relationships with other taxa by quantifying the bipartitions in which it was included from a group of single protein phylogenetic trees in a way that allowed for variation in taxonomic content and accounted for paralogous sequences. The largest number of sequences supported a phylogenetic relationship of E. huxleyi with the stramenopiles, in particular Aureococcus anophagefferens. Far fewer nuclear sequences gave strong support to the placement of this coccolithophorid with the cryptophyte, Guillardia theta. The majority of the sequences that did support this relationship did not have plastid related functions. These results suggest that the haptophytes may be more closely allied with the heterokonts than with the cryptophytes. Another small set of genes associated E. huxleyi with the Viridiplantae with high support. While these genes could have been acquired with a plastid, the lack of plastid related functions among the proteins for which they code and the lack of other organisms with chlorophyll c containing plastids within these bipartitions suggests other explanations may be possible. This study also identified several genes that may have been transferred from the haptophyte lineage to the dinoflagellates Karenia brevis and Karlodinium veneficum as a result of their haptophyte derived plastid, including some with non-photosynthetic functions. Published by Elsevier B.V.

  3. Transformation techniques for metabolic engineering of diatoms and haptophytes: current state and prospects.

    Science.gov (United States)

    Velmurugan, Natarajan; Deka, Deepi

    2018-05-01

    Diatoms and haptophytes represent a key segment of the dominant phytoplankton communities that frequently form massive blooms in the photic zone of the ocean and are considered indicators of global climate changes. Diatoms and haptophytes also play a vital role in the biological carbon fixation in the carbon cycles. Carbon partitioning within diatoms and haptophytes possesses a wide range of chemical compounds and storage materials, such as lipids, carbohydrates, and chlorophyll. Among the marine microorganisms, diatoms and haptophytes have been recognized as promising sources of long- and very long-chain polyunsaturated fatty acids (PUFA). So far, a variety of approaches have been employed for genetic modification in the nuclei of diatoms and haptophytes. Studies on transformation and metabolic engineering in various intracellular genomes, such as chloroplast and mitochondria, are scarce. Particle bombardment, Agrobacterium and PEG-mediated gene transfer, and electroporation have been reported for foreign gene transformation into the diatoms and haptophytes. Antibiotics (G418 and chloramphenicol) and herbicides (zeocin, hygromycin, and norflurazon) have been successfully demonstrated as the best selection markers. Despite the availability of a wide range of molecular tools for foreign gene expression in microalgae, very few promoters (lhcf1, nr, h4, ef2, fcp, and pds) have been reported for diatoms and haptophytes. Therefore, in this review, we first summarize the significant progress that has been achieved in transgene expression in diatoms and haptophytes and highlight the importance and availability of recently developed novel tools that are suitable for transgenic expression in diatoms and haptophytes.

  4. Seasonal Dynamics of Haptophytes and dsDNA Algal Viruses Suggest Complex Virus-Host Relationship.

    Science.gov (United States)

    Johannessen, Torill Vik; Larsen, Aud; Bratbak, Gunnar; Pagarete, António; Edvardsen, Bente; Egge, Elianne D; Sandaa, Ruth-Anne

    2017-04-20

    Viruses influence the ecology and diversity of phytoplankton in the ocean. Most studies of phytoplankton host-virus interactions have focused on bloom-forming species like Emiliania huxleyi or Phaeocystis spp. The role of viruses infecting phytoplankton that do not form conspicuous blooms have received less attention. Here we explore the dynamics of phytoplankton and algal viruses over several sequential seasons, with a focus on the ubiquitous and diverse phytoplankton division Haptophyta, and their double-stranded DNA viruses, potentially with the capacity to infect the haptophytes. Viral and phytoplankton abundance and diversity showed recurrent seasonal changes, mainly explained by hydrographic conditions. By 454 tag-sequencing we revealed 93 unique haptophyte operational taxonomic units (OTUs), with seasonal changes in abundance. Sixty-one unique viral OTUs, representing Megaviridae and Phycodnaviridae , showed only distant relationship with currently isolated algal viruses. Haptophyte and virus community composition and diversity varied substantially throughout the year, but in an uncoordinated manner. A minority of the viral OTUs were highly abundant at specific time-points, indicating a boom-bust relationship with their host. Most of the viral OTUs were very persistent, which may represent viruses that coexist with their hosts, or able to exploit several host species.

  5. Salinity dependent hydrogen isotope fractionation in alkenones produced by coastal and open ocean haptophyte algae

    NARCIS (Netherlands)

    M'boule, D.; Chivall, D.; Sinke-Schoen, D.; Sinninghe Damsté, J.S.; Schouten, S.; van der Meer, M.T.J.

    2014-01-01

    The hydrogen isotope fractionation in alkenones produced by haptophyte algae is a promising new proxy for paleosalinity reconstructions. To constrain and further develop this proxy the coastal haptophyte Isochrysis galbana and the open ocean haptophyte alga Emiliania huxleyi were cultured at

  6. Genetic Diversity of Globally Dispersed Lacustrine Group I Haptophytes: Implications for Quantitative Temperature Reconstructions

    Science.gov (United States)

    Richter, N.; Longo, W. M.; Amaral-Zettler, L. A.; Huang, Y.

    2017-12-01

    There are significant uncertainties surrounding the forcings that drive terrestrial temperature changes on local and regional scales. Quantitative temperature reconstructions from terrestrial sites, such as lakes, help to unravel the fundamental processes that drive changes in temperature on different temporal and spatial scales. Recent studies at Brown University show that distinct alkenones, long chain ketones produced by haptophytes, are found in many freshwater, alkaline lakes in the Northern Hemisphere, highlighting these systems as targets for quantitative continental temperature reconstructions. These freshwater alkenones are produced by the Group I haptophyte phylotype and are characterized by a distinct signature: the presence of isomeric tri-unsaturated ketones and absence of alkenoates. There are currently no cultured representatives of the "Group I" haptophytes, hence they are only known based on their rRNA gene signatures. Here we present robust evidence that Northern Hemispheric freshwater, alkaline lakes with the characteristic "Group I" alkenone signature all host the same clade of Isochrysidales haptophytes. We employed next generation DNA amplicon sequencing to target haptophyte specific hypervariable regions of the large and small-subunit ribosomal RNA gene from 13 different lakes from three continents (i.e., North America, Europe, and Asia). Combined with previously published sequences, our genetic data show that the Group I haptophyte is genetically diverse on a regional and global scale, and even within the same lake. We present two case studies from a suite of five lakes in Alaska and three in Iceland to assess the impact of various environmental factors affecting Group I diversity and alkenone production. Despite the genetic diversity in this group, the overall ketone signature is conserved. Based on global surface sediment samples and in situ Alaskan lake calibrations, alkenones produced by different operational taxonomic units of the Group

  7. Atypical adult non-calcified pilomatricoma

    International Nuclear Information System (INIS)

    Masih, S.; Gentili, A.; Sorenson, S.M.; Seeger, L.L.

    2000-01-01

    We present a rare case of a non-calcified pilomatricoma in a 67-year-old man. This tumor was extremely large in size, and its location, in the lower extremity, was very unusual. The clinical, radiographic, and histopathological features are described in detail. The role of magnetic resonance imaging (MRI) in the diagnosis of this entity is discussed. Definite internal reticulations and septations were observed. A possible explanation for this observation is that the high signal intensity reticulations may represent edematous stroma surrounding basaloid cells. (orig.)

  8. Making the invisible visible: improving conspicuity of noncalcified gallstones using dual-energy CT.

    Science.gov (United States)

    Uyeda, Jennifer W; Richardson, Ian J; Sodickson, Aaron D

    2017-12-01

    To determine whether virtual monochromatic imaging (VMI) increases detectability of noncalcified gallstones on dual-energy CT (DECT) compared with conventional CT imaging. This retrospective IRB-approved, HIPAA-compliant study included consecutive patients who underwent DECT of the abdomen in the Emergency Department during a 30-month period (July 1, 2013-December 31, 2015), with a comparison US or MR within 1-year. 51 patients (36F, 15M; mean age 52 years) fulfilled the inclusion criteria. All DECT were acquired on a dual-source 128 × 2 slice scanner using either 80/Sn140 or 100/Sn140 kVp pairs. Source images at high and low kVp were used for DE post-processing with VMI. Within 3 mm reconstructed images, regions of interest of 0.5 cm 2 were placed on noncalcified gallstones and bile to record hounsfield units (HU) at VMI energy levels ranging between 40 and 190 keV. Noncalcified gallstones uniformly demonstrated lowest HU at 40 keV and increase at higher keV; the HU of bile varied at higher keV. Few of the noncalcified stones are visible at 70 keV (simulating a conventional 120 kVp scan), with measured contrast (bile-stone HU difference) 20 HU in 2%. Contrast was maximal at 40 keV, where 100% demonstrated >20 HU difference from surrounding bile, 75% >44 HU difference, and 50% >60 HU difference. A paired t test demonstrated a significant difference (p < 0.0001) between this stone-bile contrast at 40 vs. 70 keV and 70 vs. 190 keV. Low keV virtual monochromatic imaging increased conspicuity of noncalcified gallstones, improving their detectability.

  9. Prevalence of noncalcified coronary plaque in patients with calcium score of 0: the silent enemy.

    Science.gov (United States)

    Koulaouzidis, George; Charisopoulou, Dafni; Jenkins, Paul J; Koulaouzidis, Anastasios; McArthur, Tony

    2013-04-01

    Noncalcified coronary artery plaques (NCAPs) are susceptible to rupture, resulting in coronary artery thrombosis. Using computer tomography coronary angiography (CTCA), we evaluated the prevalence and degree of stenosis caused by NCAP in patients without coronary artery calcification (CAC). A retrospective analysis of 447 symptomatic patients with 0 CAC score revealed negative CTCA in 400 (89.5%). Noncalcified coronary artery plaques were demonstrated in 47 (10.5%), with 4 presenting stenosis >50%. Patients with positive CTCA, compared to those with normal CTCA, had significantly higher mean age (56.2 years vs 50.6 years, P < .004) and higher pretest coronary artery disease (CAD) probability (26% vs 34%, P < .0001). Noncalcified coronary artery plaque was predominantly developed in the proximal segment of the left anterior descending artery. Noncalcified coronary artery plaque is present in up to 10% of patients with a CAC score of 0. Computer tomography coronary angiography could be of diagnostic value in symptomatic patients with multiple risk factors for CAD, even in the absence of CAC.

  10. Losses, Expansions, and Novel Subunit Discovery of Adaptor Protein Complexes in Haptophyte Algae.

    Science.gov (United States)

    Lee, Laura J Y; Klute, Mary J; Herman, Emily K; Read, Betsy; Dacks, Joel B

    2015-11-01

    The phylum Haptophyta (Diaphoratickes) contains marine algae that perform biomineralization, extruding large, distinctive calcium carbonate scales (coccoliths) that completely cover the cell. Coccolith production is an important part of global carbon cycling; however, the membrane trafficking pathway by which they are secreted has not yet been elucidated. In most eukaryotes, post-Golgi membrane trafficking involves five heterotetrameric adaptor protein (AP) complexes, which impart cargo selection specificity. To better understand coccolith secretion, we performed comparative genomic, phylogenetic, and transcriptomic analyses of the AP complexes in Emiliania huxleyi strains 92A, Van556, EH2, and CCMP1516, and related haptophytes Gephyrocapsa oceanica and Isochrysis galbana; the latter has lost the ability to biomineralize. We show that haptophytes have a modified membrane trafficking system (MTS), as we found both AP subunit losses and duplications. Additionally, we identified a single conserved subunit of the AP-related TSET complex, whose expression suggests a functional role in membrane trafficking. Finally, we detected novel alpha adaptin ear and gamma adaptin ear proteins, the first of their kind to be described outside of opisthokonts. These novel ear proteins and the sculpting of the MTS may support the capacity for biomineralization in haptophytes, enhancing their ability to perform this highly specialized form of secretion. Copyright © 2015 Elsevier GmbH. All rights reserved.

  11. Comparison of Digital Tomosynthesis and Chest Radiography for the Detection of Noncalcified Pulmonary and Hilar Lesions.

    Science.gov (United States)

    Galea, Angela; Adlan, Tarig; Gay, David; Roobottom, Carl; Dubbins, Paul; Riordan, Richard

    2015-09-01

    The aim of this study was to compare the sensitivity and specificity of chest digital tomosynthesis (DTS) with chest radiography (CXR) for the detection of noncalcified pulmonary nodules and hilar lesions using computed tomography (CT) as the reference standard. A total of 78 patients with suspected noncalcified pulmonary lesions on CXR were included in the study. Two radiologists, blinded to the history and CT, analyzed the CXR and the DTS images (separately), whereas a third radiologist analyzed the CXR and DTS images together. Noncalcified intrapulmonary nodules and hilar lesions were recorded for analysis. The interobserver agreement for CXR and DTS was assessed, and the time taken to report the images was recorded. A total of 202 lesions were recorded in 78 patients. There were 111 true lesions confirmed on CT in 53 patients; in 25 patients subsequent CT excluded a lesion. The overall sensitivity was 32% for CXR and 49% for DTS. This improved to 54% when the posteroanterior CXR and DTS were reviewed together (CXR-DTS). The overall specificities for CXR, DTS, and CXR-DTS were 49%, 96%, and 98%, respectively. There were 56 suspected hilar lesions with subgroup sensitivities of 76% for CXR, 65% for DTS, and 76% for CXR-DTS. The specificity for hilar lesions was 59%, 92%, and 97% for CXR, DTS, and CXR-DTS, respectively. DTS significantly improves the detectability of noncalcified nodules when compared with and when used in combination with CXR. The specificity and interobserver agreement of DTS in the diagnosis of suspected noncalcified pulmonary nodules and hilar lesions are significantly better than those of CXR and approaches those of CT.

  12. Rapid detection and quantification of haptophyte alkenones by Fourier transform infrared spectroscopy (FTIR)

    Czech Academy of Sciences Publication Activity Database

    Pelusi, A.; Hanawa, Y.; Araie, H.; Suzuki, I.; Giordano, Mario; Shiraiwa, I.

    2016-01-01

    Roč. 19, NOVEMBER 2016 (2016), s. 48-56 ISSN 2211-9264 Institutional support: RVO:61388971 Keywords : Rapid detection * haptophyte alkenones * Fourier spectroscopy Subject RIV: EE - Microbiology, Virology Impact factor: 3.994, year: 2016

  13. Seasonal diversity and dynamics of haptophytes in the Skagerrak, Norway, explored by high-throughput sequencing

    Science.gov (United States)

    Egge, Elianne Sirnæs; Johannessen, Torill Vik; Andersen, Tom; Eikrem, Wenche; Bittner, Lucie; Larsen, Aud; Sandaa, Ruth-Anne; Edvardsen, Bente

    2015-01-01

    Microalgae in the division Haptophyta play key roles in the marine ecosystem and in global biogeochemical processes. Despite their ecological importance, knowledge on seasonal dynamics, community composition and abundance at the species level is limited due to their small cell size and few morphological features visible under the light microscope. Here, we present unique data on haptophyte seasonal diversity and dynamics from two annual cycles, with the taxonomic resolution and sampling depth obtained with high-throughput sequencing. From outer Oslofjorden, S Norway, nano- and picoplanktonic samples were collected monthly for 2 years, and the haptophytes targeted by amplification of RNA/cDNA with Haptophyta-specific 18S rDNA V4 primers. We obtained 156 operational taxonomic units (OTUs), from c. 400.000 454 pyrosequencing reads, after rigorous bioinformatic filtering and clustering at 99.5%. Most OTUs represented uncultured and/or not yet 18S rDNA-sequenced species. Haptophyte OTU richness and community composition exhibited high temporal variation and significant yearly periodicity. Richness was highest in September–October (autumn) and lowest in April–May (spring). Some taxa were detected all year, such as Chrysochromulina simplex, Emiliania huxleyi and Phaeocystis cordata, whereas most calcifying coccolithophores only appeared from summer to early winter. We also revealed the seasonal dynamics of OTUs representing putative novel classes (clades HAP-3–5) or orders (clades D, E, F). Season, light and temperature accounted for 29% of the variation in OTU composition. Residual variation may be related to biotic factors, such as competition and viral infection. This study provides new, in-depth knowledge on seasonal diversity and dynamics of haptophytes in North Atlantic coastal waters. PMID:25893259

  14. Seasonal diversity and dynamics of haptophytes in the Skagerrak, Norway, explored by high-throughput sequencing.

    Science.gov (United States)

    Egge, Elianne Sirnaes; Johannessen, Torill Vik; Andersen, Tom; Eikrem, Wenche; Bittner, Lucie; Larsen, Aud; Sandaa, Ruth-Anne; Edvardsen, Bente

    2015-06-01

    Microalgae in the division Haptophyta play key roles in the marine ecosystem and in global biogeochemical processes. Despite their ecological importance, knowledge on seasonal dynamics, community composition and abundance at the species level is limited due to their small cell size and few morphological features visible under the light microscope. Here, we present unique data on haptophyte seasonal diversity and dynamics from two annual cycles, with the taxonomic resolution and sampling depth obtained with high-throughput sequencing. From outer Oslofjorden, S Norway, nano- and picoplanktonic samples were collected monthly for 2 years, and the haptophytes targeted by amplification of RNA/cDNA with Haptophyta-specific 18S rDNA V4 primers. We obtained 156 operational taxonomic units (OTUs), from c. 400.000 454 pyrosequencing reads, after rigorous bioinformatic filtering and clustering at 99.5%. Most OTUs represented uncultured and/or not yet 18S rDNA-sequenced species. Haptophyte OTU richness and community composition exhibited high temporal variation and significant yearly periodicity. Richness was highest in September-October (autumn) and lowest in April-May (spring). Some taxa were detected all year, such as Chrysochromulina simplex, Emiliania huxleyi and Phaeocystis cordata, whereas most calcifying coccolithophores only appeared from summer to early winter. We also revealed the seasonal dynamics of OTUs representing putative novel classes (clades HAP-3-5) or orders (clades D, E, F). Season, light and temperature accounted for 29% of the variation in OTU composition. Residual variation may be related to biotic factors, such as competition and viral infection. This study provides new, in-depth knowledge on seasonal diversity and dynamics of haptophytes in North Atlantic coastal waters. © 2015 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

  15. Non-calcifying and Langerhans cell-rich variant of calcifying epithelial odontogenic tumor

    Directory of Open Access Journals (Sweden)

    Hung-Pin Lin

    2016-06-01

    Full Text Available This study reported the clinicopathological features, treatment and prognosis of nine cases of noncalcifying and Langerhans cell (LC-rich calcifying epithelial odontogenic tumor (CEOT collected from the English literature. Of the nine cases, seven were intraosseous and two were extraosseous. All nine tumors were found in Asian patients. The age of the nine patients ranged from 20 years to 58 years with a mean age of 41 years. There were five female and four male patients. The seven intraosseous cases included six in the anterior and premolar region of the maxilla and one in the posterior region and ascending ramus of the mandible. The two extraosseous cases were located at the upper lateral incisor and premolar gingivae, respectively. Of the seven intraosseous cases, five showed unilocular and two multilocular radiolucency without foci of calcification. Six of the seven intraosseous cases showed resorption of the tooth roots in the tumor-involved region. Histologically, noncalcifying and LC-rich CEOTs were composed of small nests and thin strands of tumor epithelial cells with a relatively high number of LCs among them. This was the reason why we classed these nine cases as noncalcifying and LC-rich CEOTs. Two extraosseous cases received total excision of the gingival mass. For the seven intraosseous cases, four accepted partial maxillectomy or mandibulectomy, two received total excision or enucleation, and one underwent curettage. The six cases with the follow-up information available showed no tumor recurrence after a follow-up period of 6 months to 10 years.

  16. Advances in Alkenone Paleotemperature Proxies: Analytical Methods, Novel Structures and Haptophyte Species, Biosynthesis, New indices and Ecological Aspects

    Science.gov (United States)

    Huang, Y.; Longo, W. M.; Zheng, Y.; Richter, N.; Dillon, J. T.; Theroux, S.; D'Andrea, W. J.; Toney, J. L.; Wang, L.; Amaral-Zettler, L. A.

    2017-12-01

    Alkenones are mature, well-established paleo-sea surface temperature proxies that have been widely applied for more than three decades. However, recent advances across a broad range of alkenone-related topics at Brown University are inviting new paleoclimate and paleo-environmental applications for these classic biomarkers. In this presentation, I will summarize our progress in the following areas: (1) Discovery of a freshwater alkenone-producing haptophyte species and structural elucidation of novel alkenone structures unique to the species, performing in-situ temperature calibrations, and classifying alkenone-producing haptophytes into three groups based on molecular ecological approaches (with the new species belonging to Group I Isochrysidales); (2) A global survey of Group I haptophyte distributions and environmental conditions favoring the presence of this alga, as well as examples of using Group I alkenones for paleotemperature reconstructions; (3) New gas chromatographic columns that allow unprecedented resolution of alkenones and alkenoates and associated structural isomers, and development of a new suite of paleotemperature and paleoenvironmental proxies; (4) A new liquid chromatographic separation technique that allows efficient cleanup of alkenones and alkenoates (without the need for saponification) for subsequent coelution-free gas chromatographic analysis; (5) Novel structural features revealed by new analytical methods that now allow a comprehensive re-assessment of taxonomic features of various haptophyte species, with principal component analysis capable of fully resolving species biomarker distributions; (6) Development of UK37 double prime (UK37'') for Group II haptophytes (e.g., those occurring in saline lakes and estuaries), that differs from the traditional unsaturation indices used for SST reconstructions; (7) New assessment of how mixed inputs from different alkenone groups may affect SST reconstructions in marginal ocean environments and

  17. n-Nonacosadienes from the marine haptophytes Emiliania huxleyi and Gephyrocapsa oceanica.

    Science.gov (United States)

    Nakamura, Hideto; Sawada, Ken; Araie, Hiroya; Suzuki, Iwane; Shiraiwa, Yoshihiro

    2015-03-01

    The hydrocarbons in cultures of marine haptophytes Emiliania huxleyi NIES837 and Gephyrocapsa oceanica NIES1315 were analyzed, and nonacosadienes and hentriacontadienes were detected as the major compounds in both strains. C29 and C31 monoenes and di-, tri- and tetra-unsaturated C33 alkenes were also detected as minor compounds but not C37 and C38 alkenes. The positions of the double bonds in the C29 and C31 alkenes were determined by mass spectrometry of their dimethyl disulfide (DMDS) adducts. Among the four C29 alkenes identified, the most abundant isomer was 2,20-nonacosadiene, and the other three compounds were 1,20-nonacosadiene, 3,20-nonacosadiene and 9-nonacosene, respectively. Hitherto, 2,20-nonacosadiene and 3,20-nonacosadiene were unknown to be natural products. The double bond at the n-9 (ω9) position in these C29 alkenes is hypothesized to be derived from precursors of unsaturated fatty acids possessing an n-9 double bond, such as (9Z)-9-octadecenoic acid. Nonacosadienes have the potential for being used as distinct haptophyte biomarkers. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Isolation and Characterization of a Double Stranded DNA Megavirus Infecting the Toxin-Producing Haptophyte Prymnesium parvum

    Directory of Open Access Journals (Sweden)

    Ben A. Wagstaff

    2017-03-01

    Full Text Available Prymnesium parvum is a toxin-producing haptophyte that causes harmful algal blooms globally, leading to large-scale fish kills that have severe ecological and economic implications. For the model haptophyte, Emiliania huxleyi, it has been shown that large dsDNA viruses play an important role in regulating blooms and therefore biogeochemical cycling, but much less work has been done looking at viruses that infect P. parvum, or the role that these viruses may play in regulating harmful algal blooms. In this study, we report the isolation and characterization of a lytic nucleo-cytoplasmic large DNA virus (NCLDV collected from the site of a harmful P. parvum bloom. In subsequent experiments, this virus was shown to infect cultures of Prymnesium sp. and showed phylogenetic similarity to the extended Megaviridae family of algal viruses.

  19. Symbiodinium mitigate the combined effects of hypoxia and acidification on a noncalcifying cnidarian

    KAUST Repository

    Klein, Shannon G.

    2017-04-08

    Anthropogenic nutrient inputs enhance microbial respiration within many coastal ecosystems, driving concurrent hypoxia and acidification. During photosynthesis, Symbiodinium spp., the microalgal endosymbionts of cnidarians and other marine phyla, produce O and assimilate CO and thus potentially mitigate the exposure of the host to these stresses. However, such a role for Symbiodinium remains untested for noncalcifying cnidarians. We therefore contrasted the fitness of symbiotic and aposymbiotic polyps of a model host jellyfish (Cassiopea sp.) under reduced O (~2.09 mg/L) and pH (~ 7.63) scenarios in a full-factorial experiment. Host fitness was characterized as asexual reproduction and their ability to regulate internal pH and Symbiodinium performance characterized by maximum photochemical efficiency, chla content and cell density. Acidification alone resulted in 58% more asexual reproduction of symbiotic polyps than aposymbiotic polyps (and enhanced Symbiodinium cell density) suggesting Cassiopea sp. fitness was enhanced by CO-stimulated Symbiodinium photosynthetic activity. Indeed, greater CO drawdown (elevated pH) was observed within host tissues of symbiotic polyps under acidification regardless of O conditions. Hypoxia alone produced 22% fewer polyps than ambient conditions regardless of acidification and symbiont status, suggesting Symbiodinium photosynthetic activity did not mitigate its effects. Combined hypoxia and acidification, however, produced similar numbers of symbiotic polyps compared with aposymbiotic kept under ambient conditions, demonstrating that the presence of Symbiodinium was key for mitigating the combined effects of hypoxia and acidification on asexual reproduction. We hypothesize that this mitigation occurred because of reduced photorespiration under elevated CO conditions where increased net O production ameliorates oxygen debt. We show that Symbiodinium play an important role in facilitating enhanced fitness of Cassiopea sp. polyps, and

  20. Ancient DNA derived from alkenone-biosynthesizing haptophytes and other algae in Holocene sediments from the Black Sea

    NARCIS (Netherlands)

    Coolen, M.J.L.; Boere, A.; Abbas, M.; Wakeham, S.G.; Sinninghe Damsté, J.S.

    2006-01-01

    Holocene sea surface temperatures (SST) of the Black Sea have been reconstructed using sedimentary C37 unsaturated alkenones assumed to be derived from the coccolithophorid haptophyte Emiliania huxleyi, whose fossil coccoliths are an important constituent of the unit I sediments. However,

  1. Upper Devonian (Frasnian) non-calcified, algae, Alberta: Geological relevance to Leduc platforms and petroleum source rocks

    Energy Technology Data Exchange (ETDEWEB)

    Dix, G.R. (Univ. of British Columbia, Vancouver, BC (Canada))

    1990-12-01

    Several types of non-calcified fossil algae comparable to extant brown and green benithic macrophytes occur abundantly on two bedding planes in drill core from argillaceous slope carbonates of the Ireton Formation in northern Alberta. Fossiliferous strata abruptly overlie part of a stepped-back margin of the Sturgeon Lake carbonate platform (Leduc Formation), southeast of the Peace River Arch. Fossils are flattened organic fragments, some representing nearly complete specimens. Tentative comparisons are made with some Paleozoic algae; some of the Sturgeon Lake flora may be new species or genera. Preliminary examination of selected cores from the Ireton Formation and organic-rich Duvernay Formation in central Alberta indicates a widespread distribution of algal-derived organic matter within Upper Devonian basinal strata. The geological relevance of non-calcified algae to Devonian carbonate platforms and basins is postulated in three cases. Their presence in slope sediments may indicate that algal lawns flourished in muddy, upper slope environments. Fossils accumulated either in situ, or were ripped up and quickly buried within downshope resedimented deposits. All or some algal fragments may have been swept from the adjacent carbonate platform during storms. Prolific shallow water algal growth may have occurred simultaneously with oceanic crises when shallow water carbonate production either decreased or was shut down. The present position of fossil algae, therefore, would mark a bedding surface that is stratigraphically equivalent to an intraplatform disconformity. Regardless of the original environment, a sufficient accumulation of non-calcified algae in slope strata represents a viable petroleum source proximal to carbonate platforms. 46 refs., 9 figs.

  2. 454 pyrosequencing to describe microbial eukaryotic community composition, diversity and relative abundance: a test for marine haptophytes.

    Directory of Open Access Journals (Sweden)

    Elianne Egge

    Full Text Available Next generation sequencing of ribosomal DNA is increasingly used to assess the diversity and structure of microbial communities. Here we test the ability of 454 pyrosequencing to detect the number of species present, and assess the relative abundance in terms of cell numbers and biomass of protists in the phylum Haptophyta. We used a mock community consisting of equal number of cells of 11 haptophyte species and compared targeting DNA and RNA/cDNA, and two different V4 SSU rDNA haptophyte-biased primer pairs. Further, we tested four different bioinformatic filtering methods to reduce errors in the resulting sequence dataset. With sequencing depth of 11000-20000 reads and targeting cDNA with Haptophyta specific primers Hap454 we detected all 11 species. A rarefaction analysis of expected number of species recovered as a function of sampling depth suggested that minimum 1400 reads were required here to recover all species in the mock community. Relative read abundance did not correlate to relative cell numbers. Although the species represented with the largest biomass was also proportionally most abundant among the reads, there was generally a weak correlation between proportional read abundance and proportional biomass of the different species, both with DNA and cDNA as template. The 454 sequencing generated considerable spurious diversity, and more with cDNA than DNA as template. With initial filtering based only on match with barcode and primer we observed 100-fold more operational taxonomic units (OTUs at 99% similarity than the number of species present in the mock community. Filtering based on quality scores, or denoising with PyroNoise resulted in ten times more OTU99% than the number of species. Denoising with AmpliconNoise reduced the number of OTU99% to match the number of species present in the mock community. Based on our analyses, we propose a strategy to more accurately depict haptophyte diversity using 454 pyrosequencing.

  3. Growth phase dependent hydrogen isotopic fractionation in alkenone-producing haptophytes

    Directory of Open Access Journals (Sweden)

    M. D. Wolhowe

    2009-08-01

    Full Text Available Recent works have investigated use of the hydrogen isotopic composition of C37 alkenones (δDK37s, lipid biomarkers of certain haptophyte microalgae, as an independent paleosalinity proxy. We discuss herein the factors impeding the success of such an application and identify the potential alternative use of δDK37s measurements as a proxy for non-thermal, physiological stress impacts on the U37K' paleotemperature index. Batch-culture experiments with the haptophyte Emiliania huxleyi (CCMP 1742 were conducted to determine the magnitude and variability of the isotopic contrasts between individual C37 alkenones. Further experiments were conducted with Emiliania huxleyi (CCMP 1742 andGephyrocapsa oceanica (PZ3-1 to determine whether, and to what extent, δDK37s varies between the physiological extremes of nutrient-replete exponential growth and nutrient-depleted senescence. Emiliania huxleyi was observed to exhibit an isotopic contrast between di- and tri-unsaturated C37 alkenones (αK37:3-K37:2≈0.97 that is nearly identical to that reported recently by others for environmental samples. Furthermore, this contrast appears to be constant with growth stage. The consistency of the offset across different growth stages suggests that a single, well-defined value for αK37:3-K37:2 may exist and that its use in an isotope mass-balance will allow accurate determination of δD values for individual alkenones without having to rely on time- and labor-intensive chemical separations. The isotopic fractionation between growth medium and C37 alkenones was observed to increase dramatically upon the onset of nutrient-depletion-induced senescence, suggesting that δDK37s may serve as an objective tool for recognizing and potentially correcting, at least semi-quantitatively, for the effects

  4. Widespread occurrence of distinct alkenones from Group I haptophytes in freshwater lakes: Implications for paleotemperature and paleoenvironmental reconstructions

    Science.gov (United States)

    Longo, William M.; Huang, Yongsong; Yao, Yuan; Zhao, Jiaju; Giblin, Anne E.; Wang, Xian; Zech, Roland; Haberzettl, Torsten; Jardillier, Ludwig; Toney, Jaime; Liu, Zhonghui; Krivonogov, Sergey; Kolpakova, Marina; Chu, Guoqiang; D'Andrea, William J.; Harada, Naomi; Nagashima, Kana; Sato, Miyako; Yonenobu, Hitoshi; Yamada, Kazuyoshi; Gotanda, Katsuya; Shinozuka, Yoshitsugu

    2018-06-01

    Alkenones are C35-C42 polyunsaturated ketone lipids that are commonly employed to reconstruct changes in sea surface temperature. However, their use in coastal seas and saline lakes can be hindered by species-mixing effects. We recently hypothesized that freshwater lakes are immune to species-mixing effects because they appear to exclusively host Group I haptophyte algae, which produce a distinct distribution of alkenones with a relatively consistent response of alkenone unsaturation to temperature. To evaluate this hypothesis and explore the geographic extent of Group I haptophytes, we analyzed alkenones in sediment and suspended particulate matter samples from lakes distributed throughout the mid- and high latitudes of the Northern Hemisphere (n = 30). Our results indicate that Group I-type alkenone distributions are widespread in freshwater lakes from a range of different climates (mean annual air temperature range: -17.3-10.9 °C; mean annual precipitation range: 125-1657 mm yr-1; latitude range: 40-81°N), and are commonly found in neutral to basic lakes (pH > 7.0), including volcanic lakes and lakes with mafic bedrock. We show that these freshwater lakes do not feature alkenone distributions characteristic of Group II lacustrine haptophytes, providing support for the hypothesis that freshwater lakes are immune to species-mixing effects. In lakes that underwent temporal shifts in salinity, we observed mixed Group I/II alkenone distributions and the alkenone contributions from each group could be quantified with the RIK37 index. Additionally, we observed significant correlations of alkenone unsaturation (U37K) with seasonal and mean annual air temperature with this expanded freshwater lakes dataset, with the strongest correlation occurring during the spring transitional season (U37K = 0.029 * T - 0.49; r2 = 0.60; p < 0.0001). We present new sediment trap data from two lakes in northern Alaska (Toolik Lake, 68.632°N, 149.602°W; Lake E5, 68.643°N, 149.458

  5. Effect of salinity on the fatty acid and triacylglycerol composition of five haptophyte algae from the genera Coccolithophora, Isochrysis and Prymnesium determined by LC-MS/APCI

    Czech Academy of Sciences Publication Activity Database

    Nedbalová, L.; Střížek, A.; Sigler, Karel; Řezanka, Tomáš

    2016-01-01

    Roč. 130, October (2016), s. 64-76 ISSN 0031-9422 R&D Projects: GA ČR GA14-00227S Institutional support: RVO:61388971 Keywords : Haptophyte algae * Coccolithophyceae * Liquid chromatography-mass spectrometry Subject RIV: EE - Microbiology, Virology Impact factor: 3.205, year: 2016

  6. Framework for detection and localization of coronary non-calcified plaques in cardiac CTA using mean radial profiles.

    Science.gov (United States)

    Jawaid, Muhammad Moazzam; Riaz, Atif; Rajani, Ronak; Reyes-Aldasoro, Constantino Carlos; Slabaugh, Greg

    2017-10-01

    The high mortality rate associated with coronary heart disease (CHD) has driven intensive research in cardiac imaging and image analysis. The advent of computed tomography angiography (CTA) has turned non-invasive diagnosis of cardiovascular anomalies into reality as calcified coronary plaques can be easily identified due to their high intensity values. However, the detection of non-calcified plaques in CTA is still a challenging problem because of lower intensity values, which are often similar to the nearby blood and muscle tissues. In this work, we propose the use of mean radial profiles for the detection of non-calcified plaques in CTA imagery. Accordingly, we computed radial profiles by averaging the image intensity in concentric rings around the vessel centreline in a first stage. In the subsequent stage, an SVM classifier is applied to identify the abnormal coronary segments. For occluded segments, we further propose a derivative-based method to localize the position and length of the plaque inside the segment. A total of 32 CTA volumes were analysed and a detection accuracy of 88.4% with respect to the manual expert was achieved. The plaque localization accuracy was computed using the Dice similarity coefficient and a mean of 83.2% was achieved. The consistent performance for multi-vendor, multi-institution data demonstrates the reproducibility of our method across different CTA datasets with a good agreement with manual expert annotations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Diagnostic Performance of Breast Magnetic Resonance Imaging in Non-Calcified Equivocal Breast Findings: Results from a Systematic Review and Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Barbara Bennani-Baiti

    Full Text Available To evaluate the performance of MRI for diagnosis of breast cancer in non-calcified equivocal breast findings.We performed a systematic review and meta-analysis of peer-reviewed studies in PubMed from 01/01/1986 until 06/15/2015. Eligible were studies applying dynamic contrast-enhanced breast MRI as an adjunct to conventional imaging (mammography, ultrasound to clarify equivocal findings without microcalcifications. Reference standard for MRI findings had to be established by histopathological sampling or imaging follow-up of at least 12 months. Number of true or false positives and negatives and other characteristics were extracted, and possible bias was determined using the QUADAS-2 applet. Statistical analyses included data pooling and heterogeneity testing.Fourteen out of 514 studies comprising 2,316 lesions met our inclusion criteria. Pooled diagnostic parameters were: sensitivity (99%, 95%-CI: 93-100%, specificity (89%, 95%-CI: 85-92%, PPV (56%, 95%-CI: 42-70% and NPV (100%, 95%-CI: 99-100%. These estimates displayed significant heterogeneity (P<0.001.Breast MRI demonstrates an excellent diagnostic performance in case of non-calcified equivocal breast findings detected in conventional imaging. However, considering the substantial heterogeneity with regard to prevalence of malignancy, problem solving criteria need to be better defined.

  8. DECT evaluation of noncalcified coronary artery plaque

    Energy Technology Data Exchange (ETDEWEB)

    Ravanfar Haghighi, Rezvan [Medical Imaging Research Center and Colorectal Research Center, Shiraz University of Medical Science, Shiraz 719 363 5899 (Iran, Islamic Republic of); Chatterjee, S. [BGVS Chemical Engineering Building (Old), Indian Institute of Science, Bangalore 560012 (India); Tabin, Milo; Singh, Rishi P.; Sharma, Munish; Krishna, Karthik [Department of Forensic Medicine, All India Institute of Medical Sciences, New Delhi 110029 (India); Sharma, Sanjiv; Jagia, Priya [Department of Cardiac-Radiology, All India Institute of Medical Sciences, New Delhi 110029 (India); Ray, Ruma; Arava, Sudhir [Department of Pathology, All India Institute of Medical Sciences, New Delhi 110029 (India); Yadav, Rakesh [Department of Cardiology, All India Institute of Medical Sciences, New Delhi 110029 (India); Vani, V. C. [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore 560012 (India); Lakshmi, R.; Kumar, Pratik, E-mail: drpratikkumar@gmail.com [Department of Cardiac-Biochemistry, All India Institute of Medical Sciences, New Delhi 110029 (India); Mandal, Susama R. [Department of Medical Physics Unit IRCH, All India Institute of Medical Sciences, New Delhi 110029 (India)

    2015-10-15

    are practically nonexistent, and microcalcification, as observed in histopathology, has to be taken into account to explain the nature of the observed (ρ{sub e}, Z{sub eff}) data. This also enables us to judge the composition of the plaque in terms of basic model which considers the plaque to be composed of fibres, lipids, and microcalcification. Conclusions: This simple and reliable method has the potential as an effective modality to investigate the composition of noncalcified coronary artery plaques and thus help in their characterization. In this inversion method, (ρ{sub e}, Z{sub eff}) of the scanned sample can be found by eliminating the effects of the CT machine and also by ensuring that the determination of the two unknowns (ρ{sub e}, Z{sub eff}) does not interfere with each other and the nature of the plaque can be identified in terms of a three component model.

  9. Enzymological evidence for the function of a plastid-located pyruvate carboxylase in the Haptophyte alga Emiliania huxleyi: a novel pathway for the production of C4 compounds.

    Science.gov (United States)

    Tsuji, Yoshinori; Suzuki, Iwane; Shiraiwa, Yoshihiro

    2012-06-01

    Pyruvate carboxylase (PYC) catalyzes the β-carboxylation of pyruvate to yield oxaloacetate (OAA). We previously isolated a cDNA encoding a putative PYC (EhPYC1) from the haptophyte alga Emiliania huxleyi and then proposed that EhPYC1 contributes to active anaplerotic β-carboxylation during photosynthesis although PYC activity was not detected in the cell extracts. Involvement of PYC in photosynthetic carbon metabolism is unique, since PYC generally functions in non-photosynthetic organisms. In the present study, we demonstrate that EhPYC1 is highly sensitive to endogenous proteases and therefore is easily degraded in cell extracts. By avoiding proteolytic degradation, PYC activity can be detected in the cell extracts of E. huxleyi. The activity of a recombinant His-tagged EhPYC1 expressed in Streptomyces lividans was inhibited by l-malate in a mixed non-competitive manner. Immunofluorescence labeling showed that EhPYC1 is located in the plastid. This result agrees with the prediction that a bipartite plastid-targeting signal is present that functions to deliver proteins into the four-membrane plastid of haptophyte algae. This is the first finding of a plastid-located PYC. These results indicate that E. huxleyi possesses a unique pathway to produce OAA catalyzed by PYC, and the pathway may provide carbon skeletons for amino acid biosynthesis in the plastid. A database search indicates that PYC genes are widespread in green algae, diatoms and brown algae, suggesting the crucial role of PYC in various aquatic phototrophs.

  10. Non-calcified coronary plaque volume inversely related to CD4 count in HIV infection

    Science.gov (United States)

    Duarte, Horacio; Matta, Jatin R.; Muldoon, Nancy; Masur, Henry; Hadigan, Colleen; Gharib, Ahmed M.

    2013-01-01

    Background Non-calcified coronary artery plaque (NCAP) may be an important predictor of cardiovascular events, however, few studies have directly measured NCAP in HIV-infected individuals. Methods We completed a prospective cross-sectional evaluation of NCAP and coronary calcium scores using CT angiography in HIV-infected subjects (n=26) without known coronary artery disease (CAD), but who had one or more CAD risk factor and compared them to controls matched on age, race, sex, body mass index and Framingham risk score (n=26). Results There was no difference in coronary calcium scores (114 ± 218 vs. 124 ± 298 p=0.89) or NCAP volume (65 ± 86 mm3 vs. 63 ± 82 mm3, p=0.38) between HIV-infected subjects and controls, respectively. Among HIV-infected subjects, lower CD4 count was associated with increased NCAP volume (r=-0.52, p=0.006). CD4 count remained a significant predictor of NCAP in a multivariate analysis that adjusted for age and duration of antiretroviral therapy. Conclusion Plaque burden is similar between HIV-infected and uninfected individuals when matched on traditional CAD risk factors, however immune function may mediate the development of atherosclerosis in HIV infection. PMID:22293714

  11. Non-calcified coronary plaque volume inversely related to CD4(+) T-cell count in HIV infection.

    Science.gov (United States)

    Duarte, Horacio; Matta, Jatin R; Muldoon, Nancy; Masur, Henry; Hadigan, Colleen; Gharib, Ahmed M

    2012-01-01

    Non-calcified coronary artery plaque (NCAP) might be an important predictor of cardiovascular events; however, few studies have directly measured NCAP in HIV-infected individuals. We completed a prospective cross-sectional evaluation of NCAP and coronary calcium scores using computed tomography angiography in HIV-infected patients (n=26) without known coronary artery disease (CAD), but who had one or more CAD risk factor(s), and compared them with controls matched on age, race, sex, body mass index and Framingham Risk Score (n=26). There was no difference in coronary calcium scores (114 ± 218 versus 124 ± 298; P=0.89) or NCAP volume (65 ± 86 mm(3) versus 63 ± 82 mm(3); P=0.38) between HIV-infected patients and controls, respectively. Among HIV-infected patients, lower CD4(+) T-cell count was associated with increased NCAP volume (r=-0.52, P=0.006). The CD4(+) T-cell count remained a significant predictor of NCAP in a multivariate analysis that adjusted for age and duration of antiretroviral therapy. Plaque burden is similar between HIV-infected and uninfected individuals when matched on traditional CAD risk factors; however, immune function might mediate the development of atherosclerosis in HIV infection.

  12. An exceptional horizontal gene transfer in plastids: gene replacement by a distant bacterial paralog and evidence that haptophyte and cryptophyte plastids are sisters

    Directory of Open Access Journals (Sweden)

    Palmer Jeffrey D

    2006-09-01

    Full Text Available Abstract Background Horizontal gene transfer (HGT to the plant mitochondrial genome has recently been shown to occur at a surprisingly high rate; however, little evidence has been found for HGT to the plastid genome, despite extensive sequencing. In this study, we analyzed all genes from sequenced plastid genomes to unearth any neglected cases of HGT and to obtain a measure of the overall extent of HGT to the plastid. Results Although several genes gave strongly supported conflicting trees under certain conditions, we are confident of HGT in only a single case beyond the rubisco HGT already reported. Most of the conflicts involved near neighbors connected by long branches (e.g. red algae and their secondary hosts, where phylogenetic methods are prone to mislead. However, three genes – clpP, ycf2, and rpl36 – provided strong support for taxa moving far from their organismal position. Further taxon sampling of clpP and ycf2 resulted in rejection of HGT due to long-branch attraction and a serious error in the published plastid genome sequence of Oenothera elata, respectively. A single new case, a bacterial rpl36 gene transferred into the ancestor of the cryptophyte and haptophyte plastids, appears to be a true HGT event. Interestingly, this rpl36 gene is a distantly related paralog of the rpl36 type found in other plastids and most eubacteria. Moreover, the transferred gene has physically replaced the native rpl36 gene, yet flanking genes and intergenic regions show no sign of HGT. This suggests that gene replacement somehow occurred by recombination at the very ends of rpl36, without the level and length of similarity normally expected to support recombination. Conclusion The rpl36 HGT discovered in this study is of considerable interest in terms of both molecular mechanism and phylogeny. The plastid acquisition of a bacterial rpl36 gene via HGT provides the first strong evidence for a sister-group relationship between haptophyte and

  13. An exceptional horizontal gene transfer in plastids: gene replacement by a distant bacterial paralog and evidence that haptophyte and cryptophyte plastids are sisters

    Science.gov (United States)

    Rice, Danny W; Palmer, Jeffrey D

    2006-01-01

    Background Horizontal gene transfer (HGT) to the plant mitochondrial genome has recently been shown to occur at a surprisingly high rate; however, little evidence has been found for HGT to the plastid genome, despite extensive sequencing. In this study, we analyzed all genes from sequenced plastid genomes to unearth any neglected cases of HGT and to obtain a measure of the overall extent of HGT to the plastid. Results Although several genes gave strongly supported conflicting trees under certain conditions, we are confident of HGT in only a single case beyond the rubisco HGT already reported. Most of the conflicts involved near neighbors connected by long branches (e.g. red algae and their secondary hosts), where phylogenetic methods are prone to mislead. However, three genes – clpP, ycf2, and rpl36 – provided strong support for taxa moving far from their organismal position. Further taxon sampling of clpP and ycf2 resulted in rejection of HGT due to long-branch attraction and a serious error in the published plastid genome sequence of Oenothera elata, respectively. A single new case, a bacterial rpl36 gene transferred into the ancestor of the cryptophyte and haptophyte plastids, appears to be a true HGT event. Interestingly, this rpl36 gene is a distantly related paralog of the rpl36 type found in other plastids and most eubacteria. Moreover, the transferred gene has physically replaced the native rpl36 gene, yet flanking genes and intergenic regions show no sign of HGT. This suggests that gene replacement somehow occurred by recombination at the very ends of rpl36, without the level and length of similarity normally expected to support recombination. Conclusion The rpl36 HGT discovered in this study is of considerable interest in terms of both molecular mechanism and phylogeny. The plastid acquisition of a bacterial rpl36 gene via HGT provides the first strong evidence for a sister-group relationship between haptophyte and cryptophyte plastids to the

  14. Contrasting Photo-physiological Responses of the Haptophyte Phaeocystis Antarctica and the Diatom Pseudonitzschia sp. in the Ross Sea (Antarctica

    Directory of Open Access Journals (Sweden)

    Sasha Tozzi

    2017-05-01

    Full Text Available The Antarctic is a unique environment in which substantial variations in irradiance occur over a number of time scales, and as a result phytoplankton need to acclimate and adapt to these changes. We conducted field and laboratory manipulations in the Ross Sea, Antarctica to examine photophysiological differences between Phaeocystis antarctica and Pseudonitzschia sp. a diatom that commonly occurrs in the Ross Sea, since these are the two functional groups that dominate abundance and productivity. Both exhibited reduced quantum yields due to high irradiances. P. antarctica, a haptophyte, displays a distinct photophysiological response to irradiance when compared to diatoms. P. antarctica showed a rapid recovery from high light exposure, as indicated by the rapid return to initial, high quantum yields, in contrast to diatoms, which responded more slowly. Absorption cross sections were high in both forms, but those in P. antarctica were significantly higher. Both organisms recovered within 24 h to initial quantum yields, suggesting that high irradiance exposure does not have a permanent effect on these organisms. Among all micronutrient additions (iron, cobalt, zinc and vitamin B12, only iron additions resulted in rapid impacts on quantum yields. Iron limitation also can result in reduced photosynthetic efficiency. Understanding these photophysiologial responses and the impact of oceanographic conditions provides constraints on modeling efforts of photosynthesis and primary productivity in the Antarctic.

  15. Digital Breast Tomosynthesis versus Supplemental Diagnostic Mammographic Views for Evaluation of Noncalcified Breast Lesions

    Science.gov (United States)

    Bandos, Andriy I.; Ganott, Marie A.; Sumkin, Jules H.; Kelly, Amy E.; Catullo, Victor J.; Rathfon, Grace Y.; Lu, Amy H.; Gur, David

    2013-01-01

    of 576]; P = .017) without a decrease in specificity. Conclusion: Tomosynthesis significantly improved diagnostic accuracy for noncalcified lesions compared with supplemental mammographic views. © RSNA, 2012 PMID:23143023

  16. Quantitative analysis of arterial flow properties for detection of non-calcified plaques in ECG-gated coronary CT angiography

    Science.gov (United States)

    Wei, Jun; Zhou, Chuan; Chan, Heang-Ping; Chughtai, Aamer; Agarwal, Prachi; Kuriakose, Jean; Hadjiiski, Lubomir; Patel, Smita; Kazerooni, Ella

    2015-03-01

    We are developing a computer-aided detection system to assist radiologists in detection of non-calcified plaques (NCPs) in coronary CT angiograms (cCTA). In this study, we performed quantitative analysis of arterial flow properties in each vessel branch and extracted flow information to differentiate the presence and absence of stenosis in a vessel segment. Under rest conditions, blood flow in a single vessel branch was assumed to follow Poiseuille's law. For a uniform pressure distribution, two quantitative flow features, the normalized arterial compliance per unit length (Cu) and the normalized volumetric flow (Q) along the vessel centerline, were calculated based on the parabolic Poiseuille solution. The flow features were evaluated for a two-class classification task to differentiate NCP candidates obtained by prescreening as true NCPs and false positives (FPs) in cCTA. For evaluation, a data set of 83 cCTA scans was retrospectively collected from 83 patient files with IRB approval. A total of 118 NCPs were identified by experienced cardiothoracic radiologists. The correlation between the two flow features was 0.32. The discriminatory ability of the flow features evaluated as the area under the ROC curve (AUC) was 0.65 for Cu and 0.63 for Q in comparison with AUCs of 0.56-0.69 from our previous luminal features. With stepwise LDA feature selection, volumetric flow (Q) was selected in addition to three other luminal features. With FROC analysis, the test results indicated a reduction of the FP rates to 3.14, 1.98, and 1.32 FPs/scan at sensitivities of 90%, 80%, and 70%, respectively. The study indicated that quantitative blood flow analysis has the potential to provide useful features for the detection of NCPs in cCTA.

  17. Lipid and DNA biomarker analyses of Narragansett Bay Sediments: Evaluating the UK'37 proxy in an Estuarine Environment

    Science.gov (United States)

    George, S. E.; Herbert, T.; Amaral-Zettler, L. A.; Richter, N.

    2017-12-01

    Long chain polyunsaturated alkenone (LCA) lipid biomarkers produced by haptophyte phytoplankton species within the Order Isochrysidales (Phylum Haptophyta) have proven exceptionally useful in paleotemperature studies by means of the Uk'37 and Uk37 indices. Two closely-related Group III haptophytes, Emiliania huxleyi and Gephyrocapsa oceanica are the primary alkenone synthesizers in the modern ocean, while freshwater systems host the distinct Group I phylotype, sometimes called the Greenland phylotype, in reference to the location of its original discovery. Group I haptophytes produce large quantities of the distinct C37:4 ketone, which acts as a chemical `fingerprint' in sediments. The utility of alkenones as a paleotemperature proxy in estuarine environments has remained largely untested, representing an under-utilized opportunity to construct high-resolution paleotemperature records from environments at the intersection of fluvial and marine systems. This uncertainty is due, in part, to the presence of multiple haptophyte groups in estuaries, resulting in a mixed alkenone signature. To determine the community composition of alkenone-producing haptophytes within Narragansett Bay, four geographically separated cores from within the Bay were analyzed for alkenones as well as haptophyte rRNA biomarker gene presence. Haptophyte rRNA genes (small and large subunit) were recovered from surface and near-subsurface samples, and in conjunction with alkenone profiles, reveal recent haptophyte community structure and alkenone production regimes throughout the Bay. A surprising result is the recovery of rRNA biomarker genes with a 100% match to the open-ocean alkenone producer E. huxleyi in locations away from large fresh water inputs to the Bay. Results of these analyses elucidate the effect of salinity and nutrient dynamics on alkenone-producing haptophyte communities and enhance applicability of long chain polyunsaturated alkenones as lipid biomarkers in estuarine

  18. Interacting effects of ocean acidification and warming on growth and DMS-production in the haptophyte coccolithophore Emiliania huxleyi.

    Science.gov (United States)

    Arnold, Hayley E; Kerrison, Philip; Steinke, Michael

    2013-04-01

    The production of the marine trace gas dimethyl sulfide (DMS) provides 90% of the marine biogenic sulfur in the atmosphere where it affects cloud formation and climate. The effects of increasing anthropogenic CO2 and the resulting warming and ocean acidification on trace gas production in the oceans are poorly understood. Here we report the first measurements of DMS-production and data on growth, DMSP and DMS concentrations in pH-stated cultures of the phytoplankton haptophyte Emiliania huxleyi. Four different environmental conditions were tested: ambient, elevated CO2 (+CO2 ), elevated temperature (+T) and elevated temperature and CO2 (+TCO2 ). In comparison to the ambient treatment, average DMS production was about 50% lower in the +CO2 treatment. Importantly, temperature had a strong effect on DMS production and the impacts outweighed the effects of a decrease in pH. As a result, the +T and +TCO2 treatments showed significantly higher DMS production of 36.2 ± 2.58 and 31.5 ± 4.66 μmol L(-1) cell volume (CV) h(-1) in comparison with the +CO2 treatment (14.9 ± 4.20 μmol L(-1) CV h(-1) ). As the cultures were aerated with an air/CO2 mixture, DMS was effectively removed from the incubation bottles so that concentration remained relatively low (3.6-6.1 mmol L(-1) CV). Intracellular DMSP has been shown to increase in E. huxleyi as a result of elevated temperature and/or elevated CO2 and our results are in agreement with this finding: the ambient and +CO2 treatments showed 125 ± 20.4 and 162 ± 27.7 mmol L(-1) CV, whereas +T and +TCO2 showed significantly increased intracellular DMSP concentrations of 195 ± 15.8 and 211 ± 28.2 mmol L(-1) CV respectively. Growth was unaffected by the treatments, but cell diameter decreased significantly under elevated temperature. These results indicate that DMS production is sensitive to CO2 and temperature in E. huxleyi. Hence, global environmental change that manifests in ocean acidification and warming may not result in

  19. Phytoplankton composition and biomass across the southern Indian Ocean

    DEFF Research Database (Denmark)

    Schlüter, Louise; Henriksen, Peter; Nielsen, Torkel Gissel

    2011-01-01

    prochlorophytes dominated at these two stations, but also pelagophytes, haptophytes and cyanobacteria were abundant. Haptophytes Type 6 (sensu Zapata et al., 2004), most likely Emiliania huxleyi, and pelagophytes were the dominating eucaryotes in the southern Indian Ocean. Prochlorophytes dominated...

  20. Serial changes of coronary atherosclerotic plaque: Assessment with 64-slice multi-detector computed tomography

    International Nuclear Information System (INIS)

    Kim, Eun Young; Kang, Doo Kyoung; Sun, Joo Sung; Choi, So Yeon

    2013-01-01

    Evaluate the progression of coronary atherosclerotic plaque during follow-up, and its association with cardiovascular risk factors. Fifty-six atherosclerotic patients with plaque were enrolled in this retrospective study. Patient's plaque was detected on repeat 64-slice multidetector CT scans with a mean interval of 25 ± 10 months changes in calcified and non-calcified plaque volumes and cardiovascular risk factors were assessed over time. Absolute and relative changes in plaque volume were compared, and the association between rapid progression and cardiovascular risk factors was determined. Diameter of the stenosis, length, calcified and non-calcified lesion plaque volumes increased significantly on follow-up CT. Absolute and relative annual changes in plaque volumes were significantly greater in non-calcified plaque (median, 22.7 mm 3 , 90.4%) than in calcified plaque (median, 0.7 mm 3 , 0%). Obesity, smoking, hypertension, hypercholesterolemia, and low high-density lipoprotein were significant predictors of progression of non-calcified plaque. Progression of calcified plaque was not associated with any cardiovascular risk factors. Coronary plaque volume increased significantly on follow-up CT. The rate of progression is related to non-calcified plaque than to calcified plaque. Cardiovascular risk factors are independently associated with the rapid progression of non-calcified plaque volume, but not associated with the progression of calcified plaque.

  1. Influence of statin treatment on coronary atherosclerosis visualised using multidetector computed tomography

    International Nuclear Information System (INIS)

    Hoffmann, Hans; Frieler, Katja; Schlattmann, Peter; Hamm, Bernd; Dewey, Marc

    2010-01-01

    Coronary angiography using multidetector computed tomography (MDCT) allows non-invasive assessment of non-calcified, calcified and mixed plaques. Progression of coronary plaques may be influenced by statins. Sixty-three consecutive patients underwent MDCT as a follow-up to their original CT angiography in a retrospective longitudinal study. MDCT was performed by using a voxel size of 0.5 x 0.35 x 0.35 mm 3 at two time points 25 ± 3 months apart. Non-calcified, calcified and mixed coronary plaque components were analysed by using volumetric measurement. The influence of statin, low-density lipoprotein (LDL) and risk factors was assessed by using a linear random intercept model for plaque growth. The volumes of non-calcified, calcified and mixed coronary plaques significantly (P 3 ) to follow-up (29/17-44, 13/6-29 and 41/20-75 mm 3 ). Statins significantly slowed the growth of non-calcified plaques (statin coefficient β = -0.0036, P = 0.01) but did not significantly affect the growth rate of mixed or calcified plaques. The effect of statin treatment on non-calcified plaques remained significant after adjusting for LDL levels and cardiac risk factors. Quantification using MDCT shows that progression of non-calcified coronary plaques may be slowed by statins. (orig.)

  2. In situ survey of life cycle phases of the coccolithophore Emiliania huxleyi (Haptophyta).

    Science.gov (United States)

    Frada, Miguel J; Bidle, Kay D; Probert, Ian; de Vargas, Colomban

    2012-06-01

    The cosmopolitan coccolithophore Emiliania huxleyi is characterized by a strongly differentiated haplodiplontic life cycle consisting of a diploid phase, generally bearing coccoliths (calcified) but that can be also non-calcified, and a non-calcified biflagellated haploid phase. Given most studies have focused on the bloom-producing calcified phase, there is little-to-no information about non-calcified cells in nature. Using field mesocoms as experimental platforms, we quantitatively surveyed calcified and non-calcified cells using the combined calcareous detection fluorescent in situ hybridization (COD-FISH) method and qualitatively screened for haploid specific transcripts using reverse transcription-PCR during E. huxleyi bloom successions. Diploid, calcified cells formed dense blooms that were followed by the massive proliferation of E. huxleyi viruses (EhVs), which caused bloom demise. Non-calcified cells were also detected throughout the experiment, accounting for a minor fraction of the population but becoming progressively more abundant during mid-late bloom periods concomitant with EhV burst. Non-calcified cell growth also paralleled a distinct window of haploid-specific transcripts and the appearance of autotrophic flagellates morphologically similar to haploid cells, both of which are suggestive of meiosis and sexual life cycling during natural blooms of this prominent marine phytoplankton species. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  3. Genome Sequence and Transcriptome Analyses of Chrysochromulina tobin: Metabolic Tools for Enhanced Algal Fitness in the Prominent Order Prymnesiales (Haptophyceae.

    Directory of Open Access Journals (Sweden)

    Blake T Hovde

    Full Text Available Haptophytes are recognized as seminal players in aquatic ecosystem function. These algae are important in global carbon sequestration, form destructive harmful blooms, and given their rich fatty acid content, serve as a highly nutritive food source to a broad range of eco-cohorts. Haptophyte dominance in both fresh and marine waters is supported by the mixotrophic nature of many taxa. Despite their importance the nuclear genome sequence of only one haptophyte, Emiliania huxleyi (Isochrysidales, is available. Here we report the draft genome sequence of Chrysochromulina tobin (Prymnesiales, and transcriptome data collected at seven time points over a 24-hour light/dark cycle. The nuclear genome of C. tobin is small (59 Mb, compact (∼ 40% of the genome is protein coding and encodes approximately 16,777 genes. Genes important to fatty acid synthesis, modification, and catabolism show distinct patterns of expression when monitored over the circadian photoperiod. The C. tobin genome harbors the first hybrid polyketide synthase/non-ribosomal peptide synthase gene complex reported for an algal species, and encodes potential anti-microbial peptides and proteins involved in multidrug and toxic compound extrusion. A new haptophyte xanthorhodopsin was also identified, together with two "red" RuBisCO activases that are shared across many algal lineages. The Chrysochromulina tobin genome sequence provides new information on the evolutionary history, ecology and economic importance of haptophytes.

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

    Directory of Open Access Journals (Sweden)

    Vincent Saderne

    Full Text Available 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

  5. Influence of statin treatment on coronary atherosclerosis visualised using multidetector computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, Hans [Charite, Medical School, Freie Universitaet Berlin and Humboldt-Universitaet zu Berlin, Department of Radiology, Berlin (Germany); Klinikum Brandenburg, Department of Cardiology, Angiology, and Pulmonology, Brandenburg an der Havel (Germany); Frieler, Katja [Charite, Medical School, Freie Universitaet Berlin and Humboldt-Universitaet zu Berlin, Department of Medical Statistics, Berlin (Germany); Potsdam Institut fuer Klimaforschung, Potsdam (Germany); Schlattmann, Peter [Charite, Medical School, Freie Universitaet Berlin and Humboldt-Universitaet zu Berlin, Department of Medical Statistics, Berlin (Germany); Hamm, Bernd [Charite, Medical School, Freie Universitaet Berlin and Humboldt-Universitaet zu Berlin, Department of Radiology, Berlin (Germany); Dewey, Marc [Charite, Medical School, Freie Universitaet Berlin and Humboldt-Universitaet zu Berlin, Department of Radiology, Berlin (Germany); Charite - Universitaetsmedizin Berlin, Freie Universitaet Berlin and Humboldt-Universitaet zu Berlin, Department of Radiology (Germany)

    2010-12-15

    Coronary angiography using multidetector computed tomography (MDCT) allows non-invasive assessment of non-calcified, calcified and mixed plaques. Progression of coronary plaques may be influenced by statins. Sixty-three consecutive patients underwent MDCT as a follow-up to their original CT angiography in a retrospective longitudinal study. MDCT was performed by using a voxel size of 0.5 x 0.35 x 0.35 mm{sup 3} at two time points 25 {+-} 3 months apart. Non-calcified, calcified and mixed coronary plaque components were analysed by using volumetric measurement. The influence of statin, low-density lipoprotein (LDL) and risk factors was assessed by using a linear random intercept model for plaque growth. The volumes of non-calcified, calcified and mixed coronary plaques significantly (P < 0.001) increased from baseline (medians/interquartile ranges = 21/15-39, 7/3-20 and 36/16-69 mm{sup 3}) to follow-up (29/17-44, 13/6-29 and 41/20-75 mm{sup 3}). Statins significantly slowed the growth of non-calcified plaques (statin coefficient {beta} = -0.0036, P = 0.01) but did not significantly affect the growth rate of mixed or calcified plaques. The effect of statin treatment on non-calcified plaques remained significant after adjusting for LDL levels and cardiac risk factors. Quantification using MDCT shows that progression of non-calcified coronary plaques may be slowed by statins. (orig.)

  6. Serial changes of coronary atherosclerotic plaque: Assessment with 64-slice multi-detector computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun Young; Kang, Doo Kyoung; Sun, Joo Sung; Choi, So Yeon [Ajou University School of Medicine, Suwon (Korea, Republic of)

    2013-12-15

    Evaluate the progression of coronary atherosclerotic plaque during follow-up, and its association with cardiovascular risk factors. Fifty-six atherosclerotic patients with plaque were enrolled in this retrospective study. Patient's plaque was detected on repeat 64-slice multidetector CT scans with a mean interval of 25 ± 10 months changes in calcified and non-calcified plaque volumes and cardiovascular risk factors were assessed over time. Absolute and relative changes in plaque volume were compared, and the association between rapid progression and cardiovascular risk factors was determined. Diameter of the stenosis, length, calcified and non-calcified lesion plaque volumes increased significantly on follow-up CT. Absolute and relative annual changes in plaque volumes were significantly greater in non-calcified plaque (median, 22.7 mm{sup 3}, 90.4%) than in calcified plaque (median, 0.7 mm{sup 3}, 0%). Obesity, smoking, hypertension, hypercholesterolemia, and low high-density lipoprotein were significant predictors of progression of non-calcified plaque. Progression of calcified plaque was not associated with any cardiovascular risk factors. Coronary plaque volume increased significantly on follow-up CT. The rate of progression is related to non-calcified plaque than to calcified plaque. Cardiovascular risk factors are independently associated with the rapid progression of non-calcified plaque volume, but not associated with the progression of calcified plaque.

  7. Explaining Away Intuitions

    Directory of Open Access Journals (Sweden)

    Jonathan Ichikawa

    2009-12-01

    Full Text Available What is it to explain away an intuition? Philosophers regularly attempt to explain intuitions away, but it is often unclear what the success conditions for their project consist in. I attempt to articulate some of these conditions, taking philosophical case studies as guides, and arguing that many attempts to explain away intuitions underestimate the challenge the project of explaining away involves. I will conclude, therefore, that explaining away intuitions is a more difficult task than has sometimes been appreciated; I also suggest, however, that the importance of explaining away intuitions has often been exaggerated.

  8. Explaining Physics – What Skills does a good Explainer Need?

    CERN Multimedia

    CERN. Geneva; Bartels, Hauke

    2018-01-01

    Explaining physics in a way that it is both scientifically correct and comprehensible is a highly demanding practice. But are explanations an effective way to teach physics? Under which circumstances should a physics teacher explain – and is there such a thing as a guideline for effective instructional explanations? Of course, explaining is more than just presenting content knowledge in clear language – but what more? In our talk, we want to discuss empirical studies on instructional explanations from science education and psychology to address these questions. Among other things, we will refer to results from a large study aiming to research whether teacher education contributes to the development of explaining skills. Besides, we will give insights into a project that seeks to measure explaining skills with an interactive online test instrument.

  9. Impact of elevated CO2 concentrations on the growth and ultrastructure of non-calcifying marine diatom (Chaetoceros gracilis F.Schütt

    Directory of Open Access Journals (Sweden)

    Hanan M. Khairy

    2014-01-01

    Full Text Available The impacts of different CO2 concentrations on the growth, physiology and ultrastructure of noncalcifying microalga Chaetoceros gracilis F.Schütt (Diatom were studied. We incubated Ch. gracilis under different CO2 concentrations, preindustrial and current ambient atmospheric concentrations (285 and 385 μatm, respectively or predicted year-2100 CO2 levels (550, 750 and 1050 μatm in continuous culture conditions. The growth of Ch. gracilis measured as cell number was decreased by increasing the pCO2 concentration from nowadays concentration (385 μatm to 1050 μatm. The lowest percentage changes of oxidizable organic matter, nitrite, nitrate, phosphate and silicate were recorded at a higher pCO2 (1050 μatm, and this is in consistence with the lowest recorded cell number indicating unsuitable conditions for the growth of Ch. gracilis. The minimum cell numbers obtained at higher levels of CO2 clearly demonstrate that, low improvement occurred when the carbon level was raised. This was confirmed by a highly negative correlation between cell number and carbon dioxide partial pressure (r = −0.742, p ⩽ 0.05. On the other hand, highest growth rate at pCO2 = 385 μatm was also confirmed by the maximum uptake of nutrient salts (NO3 = 68.96 μmol.l−1, PO4 = 29.75 μmol.l−1, Si2O3 = 36.99 μmol.l−1. Total protein, carbohydrate and lipid composition showed significant differences (p ⩽ 0.05 at different carbon dioxide concentrations during the exponential growth phase (day 8. Transmission Electron Microscopy of Ch. gracilis showed enlargement of the cell, chloroplast damage, disorganization and disintegration of thylakoid membranes; cell lysis occurs at a higher CO2 concentration (1050 μatm. It is concluded from this regression equation and from the results that the growth of Ch. gracilis is expected to decrease by increasing pCO2 and increasing ocean acidification.

  10. Prognostic implications of nonobstructive coronary plaques in patients with non-ST-segment elevation myocardial infarction: a multidetector computed tomography study

    DEFF Research Database (Denmark)

    Kristensen, Thomas S; Kofoed, Klaus F; Kühl, Jørgen T

    2011-01-01

    We sought to determine whether the amount of noncalcified plaque (NCP) in nonobstructive coronary lesions as detected by multidetector computed tomography (MDCT) was a predictor of future coronary events.......We sought to determine whether the amount of noncalcified plaque (NCP) in nonobstructive coronary lesions as detected by multidetector computed tomography (MDCT) was a predictor of future coronary events....

  11. Computerized detection of noncalcified plaques in coronary CT angiography: Evaluation of topological soft gradient prescreening method and luminal analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Jun, E-mail: jvwei@umich.edu; Zhou, Chuan; Chan, Heang-Ping; Chughtai, Aamer; Agarwal, Prachi; Kuriakose, Jean; Hadjiiski, Lubomir; Patel, Smita; Kazerooni, Ella [Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2014-08-15

    Purpose: The buildup of noncalcified plaques (NCPs) that are vulnerable to rupture in coronary arteries is a risk for myocardial infarction. Interpretation of coronary CT angiography (cCTA) to search for NCP is a challenging task for radiologists due to the low CT number of NCP, the large number of coronary arteries, and multiple phase CT acquisition. The authors conducted a preliminary study to develop machine learning method for automated detection of NCPs in cCTA. Methods: With IRB approval, a data set of 83 ECG-gated contrast enhanced cCTA scans with 120 NCPs was collected retrospectively from patient files. A multiscale coronary artery response and rolling balloon region growing (MSCAR-RBG) method was applied to each cCTA volume to extract the coronary arterial trees. Each extracted vessel was reformatted to a straightened volume composed of cCTA slices perpendicular to the vessel centerline. A topological soft-gradient (TSG) detection method was developed to prescreen for NCP candidates by analyzing the 2D topological features of the radial gradient field surface along the vessel wall. The NCP candidates were then characterized by a luminal analysis that used 3D geometric features to quantify the shape information and gray-level features to evaluate the density of the NCP candidates. With machine learning techniques, useful features were identified and combined into an NCP score to differentiate true NCPs from false positives (FPs). To evaluate the effectiveness of the image analysis methods, the authors performed tenfold cross-validation with the available data set. Receiver operating characteristic (ROC) analysis was used to assess the classification performance of individual features and the NCP score. The overall detection performance was estimated by free response ROC (FROC) analysis. Results: With our TSG prescreening method, a prescreening sensitivity of 92.5% (111/120) was achieved with a total of 1181 FPs (14.2 FPs/scan). On average, six features

  12. Computerized detection of noncalcified plaques in coronary CT angiography: Evaluation of topological soft gradient prescreening method and luminal analysis

    International Nuclear Information System (INIS)

    Wei, Jun; Zhou, Chuan; Chan, Heang-Ping; Chughtai, Aamer; Agarwal, Prachi; Kuriakose, Jean; Hadjiiski, Lubomir; Patel, Smita; Kazerooni, Ella

    2014-01-01

    Purpose: The buildup of noncalcified plaques (NCPs) that are vulnerable to rupture in coronary arteries is a risk for myocardial infarction. Interpretation of coronary CT angiography (cCTA) to search for NCP is a challenging task for radiologists due to the low CT number of NCP, the large number of coronary arteries, and multiple phase CT acquisition. The authors conducted a preliminary study to develop machine learning method for automated detection of NCPs in cCTA. Methods: With IRB approval, a data set of 83 ECG-gated contrast enhanced cCTA scans with 120 NCPs was collected retrospectively from patient files. A multiscale coronary artery response and rolling balloon region growing (MSCAR-RBG) method was applied to each cCTA volume to extract the coronary arterial trees. Each extracted vessel was reformatted to a straightened volume composed of cCTA slices perpendicular to the vessel centerline. A topological soft-gradient (TSG) detection method was developed to prescreen for NCP candidates by analyzing the 2D topological features of the radial gradient field surface along the vessel wall. The NCP candidates were then characterized by a luminal analysis that used 3D geometric features to quantify the shape information and gray-level features to evaluate the density of the NCP candidates. With machine learning techniques, useful features were identified and combined into an NCP score to differentiate true NCPs from false positives (FPs). To evaluate the effectiveness of the image analysis methods, the authors performed tenfold cross-validation with the available data set. Receiver operating characteristic (ROC) analysis was used to assess the classification performance of individual features and the NCP score. The overall detection performance was estimated by free response ROC (FROC) analysis. Results: With our TSG prescreening method, a prescreening sensitivity of 92.5% (111/120) was achieved with a total of 1181 FPs (14.2 FPs/scan). On average, six features

  13. The stereochemistry of chlorophyll-c₃ from the haptophyte Emiliania huxleyi: the (13²R)-enantiomers of chlorophylls-c are exclusively selected as the photosynthetically active pigments in chromophyte algae.

    Science.gov (United States)

    Mizoguchi, Tadashi; Kimura, Yuki; Yoshitomi, Taichi; Tamiaki, Hitoshi

    2011-11-01

    Chlorophyll(Chl)-c pigments in algae, diatoms and some prokaryotes are characterized by the fully conjugated porphyrin π-system as well as the acrylate residue at the 17-position. The precise structural characterization of Chl-c(3) from the haptophyte Emiliania huxleyi was performed. The conformations of the π-conjugated peripheral substituents, the 3-/8-vinyl, 7-methoxycarbonyl and 17-acrylate moieties were evaluated, in a solution, using nuclear Overhauser enhancement correlations and molecular modeling calculations. The rotation of the 17-acrylate residue was considerably restricted, whereas the other three substituents readily rotated at ambient temperature. Moreover, the stereochemistry at the 13²-position was determined by combination of chiral high-performance liquid chromatography (HPLC) with circular dichroism (CD) spectroscopy. Compared with the CD spectra of the structurally related, synthetic (13²R)- and (13²S)-protochlorophyllide(PChlide)-a, naturally occurring Chl-c₃ had exclusively the (13²R)-configuration. To elucidate this natural selection of a single enantiomer, we analyzed the three major Chl-c pigments (Chl-c₁, c₂ and c₃) in four phylogenetically distinct classes of Chl-c containing algae, i.e., heterokontophyta, dinophyta, cryptophyta and haptophyta using chiral HPLC. All the photosynthetic organisms contained only the (13²R)-enantiomerically pure Chls-c, and lacked the corresponding enantiomeric (13²S)-forms. Additionally, Chl-c₂ was found in all the organisms as the common Chl-c. These results throw a light on the biosynthesis as well as photosynthetic function of Chl-c pigments: Chl-c₂ is derived from 8-vinyl-PChlide-a by dehydrogenation of the 17-propionate to acrylate residues as generally proposed, and the (13²R)-enantiomers of Chls-c function as photosynthetically active, light-harvesting pigments together with the principal Chl-a and carotenoids. 2011 Elsevier B.V. All rights reserved.

  14. Shock-wave lithotripsy of gallstones

    International Nuclear Information System (INIS)

    Torres, W.E.; Baumgartner, B.R.; Nelson, R.C.; Morris, S.J.

    1990-01-01

    This paper evaluates the American Dornier MPL-9000 gallstone study on the effectiveness and safety of biliary extracorporeal shock wave lithotripsy (ESWL) and, in a prospective double blind manner, the need for ursodeoxycholic acid (UDCA). At our institution, 174 symptomatic patients with gallstones (149 with noncalcified stones and 25 with calcified stones) were randomized to receive UDCA or placebo for 6 months. The gallstones were fragmented in 171/174 patients (98%). Evaluation by ultrasound was done at 6 weeks following ESWL; retreatment was done on 42/174 patients for fragments larger than 5 mm. Cholecystectomy was done in 6/174 patients. The 6- and 12- month stone-free rates were noncalcified stones + UDCA, 31% and 41%; noncalcified stones + placebo, 24% and 15%; calcified gallstones, 8% and 8%

  15. Large effect of irradiance on hydrogen isotope fractionation of alkenones in Emiliania huxleyi

    Science.gov (United States)

    van der Meer, Marcel T. J.; Benthien, Albert; French, Katherine L.; Epping, Eric; Zondervan, Ingrid; Reichart, Gert-Jan; Bijma, Jelle; Sinninghe Damsté, Jaap S.; Schouten, Stefan

    2015-07-01

    The hydrogen isotopic (δD) composition of long-chain alkenones produced by certain haptophyte algae has been suggested as a potential proxy for reconstructing paleo sea surface salinity. However, environmental parameters other than salinity may also affect the δD of alkenones. We investigated the impact of the level of irradiance on hydrogen isotopic fractionation of alkenones versus growth water by cultivating two strains of the cosmopolitan haptophyte Emiliania huxleyi at different light intensities. The hydrogen isotope fractionation decreased by approximately 40‰ when irradiance was increased from 15 to 200 μmol photons m-2 s-1 above which it was relatively constant. The response is likely a direct effect of photosystem I and II activity as the relationship of the fractionation factor α versus light intensity can be described by an Eilers-Peeters photosynthesis model. This irradiance effect is in agreement with published δD data of alkenones derived from suspended particulate matter collected from different depths in the photic zone of the Gulf of California and the eastern tropical North Pacific. However, haptophyte algae tend to bloom at relatively high light intensities (>500 μmol photons m-2 s-1) occurring at the sea surface, at which hydrogen isotope fractionation is relatively constant and not affected by changes in light intensity. Alkenones accumulating in the sediment are likely mostly derived from these surface water haptophyte blooms, when the largest amount of biomass is produced. Therefore, the observed irradiance effect is unlikely to affect the applicability of the hydrogen isotopic composition of sedimentary long chain alkenones as a proxy for paleosalinity.

  16. Plagiarism explainer for students

    OpenAIRE

    Barba, Lorena A.

    2016-01-01

    A slide deck to serve as an explainer of plagiarism in academic settings, with a personal viewpoint. For my students.Also on SpeakerDeck:https://speakerdeck.com/labarba/plagiarism-explainer-for-students(The slide viewer on SpeakerDeck is much nicer.)

  17. Synoptic relationships between surface Chlorophyll-a and diagnostic pigments specific to phytoplankton functional types

    Directory of Open Access Journals (Sweden)

    M. Noguchi-Aita

    2011-02-01

    Full Text Available Error-quantified, synoptic-scale relationships between chlorophyll-a (Chl-a and phytoplankton pigment groups at the sea surface are presented. A total of ten pigment groups were considered to represent three Phytoplankton Size Classes (PSCs, micro-, nano- and picoplankton and seven Phytoplankton Functional Types (PFTs, i.e. diatoms, dinoflagellates, green algae, prymnesiophytes (haptophytes, pico-eukaryotes, prokaryotes and Prochlorococcus sp.. The observed relationships between Chl-a and PSCs/PFTs were well-defined at the global scale to show that a community shift of phytoplankton at the basin and global scales is reflected by a change in Chl-a of the total community. Thus, Chl-a of the total community can be used as an index of not only phytoplankton biomass but also of their community structure. Within these relationships, we also found non-monotonic variations with Chl-a for certain pico-sized phytoplankton (pico-eukaryotes, Prokaryotes and Prochlorococcus sp. and nano-sized phytoplankton (Green algae, prymnesiophytes. The relationships were quantified with a least-square fitting approach in order to enable an estimation of the PFTs from Chl-a where PFTs are expressed as a percentage of the total Chl-a. The estimated uncertainty of the relationships depends on both PFT and Chl-a concentration. Maximum uncertainty of 31.8% was found for diatoms at Chl-a = 0.49 mg m−3. However, the mean uncertainty of the relationships over all PFTs was 5.9% over the entire Chl-a range observed in situ (0.02 < Chl-a < 4.26 mg m−3. The relationships were applied to SeaWiFS satellite Chl-a data from 1998 to 2009 to show the global climatological fields of the surface distribution of PFTs. Results show that microplankton are present in the mid and high latitudes, constituting only ~10.9% of the entire phytoplankton community in the mean field for 1998–2009, in which diatoms explain ~7.5%. Nanoplankton are ubiquitous throughout the global surface oceans

  18. Complexity explained

    CERN Document Server

    Erdi, Peter

    2008-01-01

    This book explains why complex systems research is important in understanding the structure, function and dynamics of complex natural and social phenomena. Readers will learn the basic concepts and methods of complex system research.

  19. The wireless internet explained

    CERN Document Server

    Rhoton, John

    2001-01-01

    The Wireless Internet Explained covers the full spectrum of wireless technologies from a wide range of vendors, including initiatives by Microsoft and Compaq. The Wireless Internet Explained takes a practical look at wireless technology. Rhoton explains the concepts behind the physics, and provides an overview that clarifies the convoluted set of standards heaped together under the umbrella of wireless. It then expands on these technical foundations to give a panorama of the increasingly crowded landscape of wireless product offerings. When it comes to actual implementation the book gives abundant down-to-earth advice on topics ranging from the selection and deployment of mobile devices to the extremely sensitive subject of security.Written by an expert on Internet messaging, the author of Digital Press''s successful Programmer''s Guide to Internet Mail and X.400 and SMTP: Battle of the E-mail Protocols, The Wireless Internet Explained describes and evaluates the current state of the fast-growing and crucial...

  20. Computer jargon explained

    CERN Document Server

    Enticknap, Nicholas

    2014-01-01

    Computer Jargon Explained is a feature in Computer Weekly publications that discusses 68 of the most commonly used technical computing terms. The book explains what the terms mean and why the terms are important to computer professionals. The text also discusses how the terms relate to the trends and developments that are driving the information technology industry. Computer jargon irritates non-computer people and in turn causes problems for computer people. The technology and the industry are changing so rapidly; it is very hard even for professionals to keep updated. Computer people do not

  1. Comparative study of coronary plaque and stenosis: CT versus MR angiography

    International Nuclear Information System (INIS)

    Liu Xin; Zhao Xihai; Cheng Liuquan; Zhao Shaohong; Cai Zulong; Cai Youquan; Yang Li

    2006-01-01

    Objective: To investigate the effect of coronary plaque composition on the extent of stenosis and compare the accuracies of coronary CTA and MRA in detecting significant stenosis (≥50%) caused by different composition plaques. Methods: Thirty patients with coronary heart disease were examined with coronary CTA, MRA and conventional coronary, angiography (CAG) within two weeks. CTA and MRA were performed with a 16-slice CT scanner and hreathhold 3D FIESTA sequence respectively. The coronary plaques were grouped as non-calcified and calcified plaque on CTA images. The accuracies and agreement of CTA and MRA in detecting significant stenosis were evaluated by two experienced radiologists independently using CAG as reference. Results: Fifty-three plaques were detected on CTA. Twenty-eight were non-calcified and the other 25 were calcified. Twenty-one of 28 non-calcified plaques caused significant stenosis on CAG. The sensitivity and specificity of CTA and MRA in detecting significant stenosis were 85.7%, 85.7% and 47.6%, 71.4%, respectively, CTA showed good agreement with CAG (K=0.65). Six of 25 calcified plaques caused significant stenosis on CAG. The sensitivity and specificity of CTA and MRA in detecting significant stenosis were 83.3%, 31.6% and 83.3%, 73.7%, respectively, MRA showed moderate agreement with CAG (K=0.46). Conclusion: CTA was accurate for detecting non-calcified plaque and stenosis, while MRA had advantage to evaluate lumen with severe calcified plaque. (authors)

  2. New perspectives on the functioning and evolution of photosymbiosis in plankton: Mutualism or parasitism?

    Science.gov (United States)

    Decelle, Johan

    2013-07-01

    Photosymbiosis is common and widely distributed in plankton and is considered to be beneficial for both partners (mutualism). Such intimate associations involving heterotrophic hosts and microalgal symbionts have been extensively studied in coral reefs, but in the planktonic realm, the ecology and evolution of photosymbioses remain poorly understood. Acantharia (Radiolaria) are ubiquitous and abundant heterotrophic marine protists, many of which host endosymbiotic microalgae. Two types of photosymbiosis involving acantharians have recently been described using molecular techniques: one found in a single acantharian species involving multiple microalgal partners (dinoflagellates and haptophytes), and the other observed in more than 25 acantharian species exclusively living with the haptophyte Phaeocystis. Contrary to most benthic and terrestrial mutualistic symbioses, these symbiotic associations share the common feature of involving symbionts that are abundant in their free-living stage. We propose a hypothetical framework that may explain this original mode of symbiosis, and discuss the ecological and evolutionary implications. We suggest that photosymbiosis in Acantharia, and probably in other planktonic hosts, may not be a mutualistic relationship but rather an "inverted parasitism," from which only hosts seem to benefit by sequestrating and exploiting microalgal cells. The relatively small population size of microalgae in hospite would prevent reciprocal evolution that can select uncooperative symbionts, therefore making this horizontally-transmitted association stable over evolutionary time. The more we learn about the diversity of life and the structure of genomes, the more it appears that much of the evolution of biodiversity is about the manipulation of other species-to gain resources and, in turn, to avoid being manipulated (John Thompson, 1999).

  3. Self-explaining roads

    NARCIS (Netherlands)

    Horst, A.R.A. van der; Kaptein, N.

    1999-01-01

    As a means to a sustainable safe traffic environment the concept of Self-Explaining Roads (SER) has been developed. The SER concept advocates a traffic environment that elicits safe driving behaviour simply by its design. In order to support safe driving behaviour and appropriate speed choice,

  4. New perspectives on the functioning and evolution of photosymbiosis in plankton

    Science.gov (United States)

    Decelle, Johan

    2013-01-01

    Photosymbiosis is common and widely distributed in plankton and is considered to be beneficial for both partners (mutualism). Such intimate associations involving heterotrophic hosts and microalgal symbionts have been extensively studied in coral reefs, but in the planktonic realm, the ecology and evolution of photosymbioses remain poorly understood. Acantharia (Radiolaria) are ubiquitous and abundant heterotrophic marine protists, many of which host endosymbiotic microalgae. Two types of photosymbiosis involving acantharians have recently been described using molecular techniques: one found in a single acantharian species involving multiple microalgal partners (dinoflagellates and haptophytes), and the other observed in more than 25 acantharian species exclusively living with the haptophyte Phaeocystis. Contrary to most benthic and terrestrial mutualistic symbioses, these symbiotic associations share the common feature of involving symbionts that are abundant in their free-living stage. We propose a hypothetical framework that may explain this original mode of symbiosis, and discuss the ecological and evolutionary implications. We suggest that photosymbiosis in Acantharia, and probably in other planktonic hosts, may not be a mutualistic relationship but rather an “inverted parasitism,” from which only hosts seem to benefit by sequestrating and exploiting microalgal cells. The relatively small population size of microalgae in hospite would prevent reciprocal evolution that can select uncooperative symbionts, therefore making this horizontally-transmitted association stable over evolutionary time. The more we learn about the diversity of life and the structure of genomes, the more it appears that much of the evolution of biodiversity is about the manipulation of other species—to gain resources and, in turn, to avoid being manipulated (John Thompson, 1999). PMID:23986805

  5. Receiver operating characteristic analysis of chest radiographs with computed radiography and conventional analog films

    International Nuclear Information System (INIS)

    Morioka, C.; Brown, K.; Dalter, S.; Milos, M.J.; Huang, H.K.; Kangarloo, H.; Boechat, I.M.; Batra, P.

    1988-01-01

    Receiver operating characteristic is used to compare the image quality of films obtained digitally using computed radiography (CR) and conventionally using analog film following fluoroscopic examination. Twenty-four cases, some with a solitary noncalcified nodule and/or pneumothorax, were collected. Ten radiologists have been tested viewing analog and CR digital films separately. Preliminary results indicate that there is no significant difference in the ability to detect either a pneumothorax or a solitary noncalcified nodule when comparing CR digital film with conventional analog film. A comparison of the CR digital image displayed on a 2,048-line monitor against analog and CR digital film is in progress

  6. Gaining from explaining: Learning improves from explaining to fictitious others on video, not from writing to them

    NARCIS (Netherlands)

    Hoogerheide, Vincent; Deijkers, Lian; Loyens, Sofie M M; Heijltjes, Anita; van Gog, Tamara

    2016-01-01

    Two experiments investigated whether studying a text with an "explanation intention" and then actually explaining it to (fictitious) other students in writing, would yield the same benefits as previously found for explaining on video. Experiment 1 had participants first studying a text either with

  7. Explaining the Gender Wealth Gap

    Science.gov (United States)

    Ruel, Erin; Hauser, Robert M.

    2013-01-01

    To assess and explain the United States’ gender wealth gap, we use the Wisconsin Longitudinal Study to examine wealth accumulated by a single cohort over 50 years by gender, by marital status, and limited to the respondents who are their family’s best financial reporters. We find large gender wealth gaps between currently married men and women, and never-married men and women. The never-married accumulate less wealth than the currently married, and there is a marital disruption cost to wealth accumulation. The status-attainment model shows the most power in explaining gender wealth gaps between these groups explaining about one-third to one-half of the gap, followed by the human-capital explanation. In other words, a lifetime of lower earnings for women translates into greatly reduced wealth accumulation. A gender wealth gap remains between married men and women after controlling for the full model that we speculate may be related to gender differences in investment strategies and selection effects. PMID:23264038

  8. SPSS explained

    CERN Document Server

    Hinton, Perry R; Brownlow, Charlotte

    2014-01-01

    SPSS Explained provides the student with all that they need to undertake statistical analysis using SPSS. It combines a step-by-step approach to each procedure with easy to follow screenshots at each stage of the process. A number of other helpful features are provided: regular advice boxes with tips specific to each test explanations divided into 'essential' and 'advanced' sections to suit readers at different levels frequently asked questions at the end of each chapter. The first edition of this popular book has been fully updated for IBM SPSS version 21 and also includes: chapters that expl

  9. [Qualitative and quantitative diagnostic performance of 320-slice computed tomography for detecting coronary artery disease with respect to atherosclerotic plaque characteristics].

    Science.gov (United States)

    Li, Suhua; Liu, Jinlai; Peng, Long; Dong, Ruimin; Wu, Huilan; Wang, Chenlin; Ni, Qiongqiong; Luo, Yanting; Zhu, Jieming; Chen, Lin

    2014-10-28

    To investigate qualitatively and quantitatively the diagnostic performance of 320-slice CT for detection of coronary artery disease with respect to different atherosclerotic plaque characteristics. A retrospective search was performed for inpatients underwent both coronary CT and further coronary angiography (CAG) from December 1, 2008 to December 31, 2012. The diagnostic performance of 320-slice CTA for detecting significant stenosis ( ≥ 50% diameter) with respect to atherosclerotic plaque characteristics were analyzed by calculating sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, kappa index (κ), and area under the receiver operating characteristic curve (AUC). Chi-square test was used to evaluate whether there were significant differences of the true-case frequency (true positive + true negative) and false-case frequency (false positive + false negative) among groups. Bland-Altman analysis was used to determine limits of agreement between CTA and CAG. A total of 454 patients and 6 779 segments were analyzed. Diagnostic accuracy was higher in non-calcified segments; whereas they decreased in the presence of both mild-moderately and heavily calcified plaques. Excellent agreement (κ = 0.810) between CT and CAG was observed for non-calcified segments, while good agreement was observed for both mild-moderately (κ = 0.701) and heavily calcified segments (κ = 0.750). Both mild-moderate (P = 0.000) and heavy (P = 0.000) calcification decreased the true-case frequency and increased the false-case frequency when compared to non-calcification. There were no significant underestimation or overestimation for non-calcified (P = 0.087) and mild-moderately calcified (P = 0.704) segments, while there was significant overestimation for heavily calcified segments (P = 0.001). Great qualitative and quantitative diagnostic performances of 320-slice CT were observed in non-calcified coronary segments. However, qualitative

  10. Observations on the morphological diversity and distribution of two siliceous nannoplankton genera, Hyalolithus and Petasaria

    DEFF Research Database (Denmark)

    Jordan, Richard W.; Abe, Kent; Cruz, Jarret

    2016-01-01

    Scale-bearing siliceous nannoplankton are occasionally encountered in surface seawater samples, but are rarely identified or illustrated. In this study, the morphological diversity of the haptophyte Hyalolithus neolepis and the enigmatic Petasaria heterolepis are investigated in scanning...

  11. Marine and terrigenous lipids in southeast atlantic sediments (leg 175) as paleoenvironmental indicators: initial results

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Schefuss, E.; Versteegh, G.J.M.; Jansen, J.H.F.

    2001-01-01

    Lipid compositions of sediments recovered during Ocean Drilling Program Leg 175 in the eastern South Atlantic reflect a variety of oceanographic and climatological environments. Most of the identified lipids can be ascribed to marine sources, notably haptophytes,

  12. It’s good to be big--- Phaeocystis antarctica colony size under the influence of zooplankton grazers

    Science.gov (United States)

    The haptophyte Phaeocystis antarctica forms extremely dense accumulations in the Ross Sea, Antarctica, and accounts for over 60% of the seasonal primary production. Similar to the Phaeocystis species in the northern hemisphere, P. antarctica exists as solitary cells and mucilagin...

  13. IT’S GOOD TO BE BIG—PHAEOCYSTIS ANTARCTICA COLONY SIZE UNDER THE INFLUENCE OF ZOOPLANKTON GRAZERS

    Science.gov (United States)

    The haptophyte Phaeocystis antarctica forms extremely dense accumulations in the Ross Sea, Antarctica, and accounts for over 60% of the seasonal primary production. Similar to the Phaeocystis species in the northern hemisphere, P. antarctica exists as solitary cells and mucilagin...

  14. Survival and Recovery of Phaeocystis Antarctica (Prymnesiophyceae) from Prolonged Darkness and Freezing

    Science.gov (United States)

    The colony-forming haptophyte Phaeocystis antarctica is an important primary producer in the Ross Sea, and must survive long periods of darkness and freezing in this extreme environment. We conducted experiments on the responses of P. antarctica-dominated phytoplankton assemblage...

  15. MAGMADIM: Young Explainers Program

    International Nuclear Information System (INIS)

    Paltiel, Z.

    2005-01-01

    Full Text:Physics teachers and educators constantly face the problem of inspiring their students to major in physics. On the other hand, science museums are designed to provide a pleasant environment which will stimulate and encourage a science associated experience to the general public. Typically, there is no intention to teach science as such in science museums. One may, however, use the science museum to teach and inspire certain groups of students in a much deeper sense. In fact they may actually enthusiastically learn much of the school physics curriculum at the museum. This report discusses the Magmadim program through which 10th graders are trained to be young explainers at the Weizmann Institutes Clore Garden of Science. To this end they study the physics underlying its exhibits in an after-school course. The ultimate goal is for the 'magmadim' to become the best possible explainers and be able to face all sorts of museum visitors. Along with learning how to instruct visitors, they must learn the physics behind the exhibits to give a full explanation of the exhibit and be able to answer any question that may arise. Our 5 year experience with the program shows that its self-selected participants not only study a lot of science, but also like it and learn how to explain the content to other people. This program, along with similar programs at the Bloomfield Science Museum and the Madatzim (young physics tutors) program of Ort, help in promoting the interest in science in general and physics in particular among school students. Various ways to expand the programs will also be discussed

  16. Do you get it? User-evaluated explainable BDI agents

    NARCIS (Netherlands)

    Broekens, J.; Harbers, M.; Hindriks, K.; Bosch, K. van den; Jonker, C.; Meyer, J.J.C.

    2010-01-01

    In this paper we focus on explaining to humans the behavior of autonomous agents, i.e., explainable agents. Explainable agents are useful for many reasons including scenario-based training (e.g. disaster training), tutor and pedagogical systems, agent development and debugging, gaming, and

  17. Thermally-assisted Magma Emplacement Explains Restless Calderas.

    Science.gov (United States)

    Amoruso, Antonella; Crescentini, Luca; D'Antonio, Massimo; Acocella, Valerio

    2017-08-11

    Many calderas show repeated unrest over centuries. Though probably induced by magma, this unique behaviour is not understood and its dynamics remains elusive. To better understand these restless calderas, we interpret deformation data and build thermal models of Campi Flegrei caldera, Italy. Campi Flegrei experienced at least 4 major unrest episodes in the last decades. Our results indicate that the inflation and deflation of magmatic sources at the same location explain most deformation, at least since the build-up of the last 1538 AD eruption. However, such a repeated magma emplacement requires a persistently hot crust. Our thermal models show that this repeated emplacement was assisted by the thermal anomaly created by magma that was intruded at shallow depth ~3 ka before the last eruption. This may explain the persistence of the magmatic sources promoting the restless behaviour of the Campi Flegrei caldera; moreover, it explains the crystallization, re-melting and mixing among compositionally distinct magmas recorded in young volcanic rocks. Our model of thermally-assisted unrest may have a wider applicability, possibly explaining also the dynamics of other restless calderas.

  18. Colony Size of Phaeocystis Antarctica (Prymnesiophyceae) as Influenced by Zooplankton Grazers

    Science.gov (United States)

    The haptophyte Phaeocystis antarctica is a dominant phytoplankton species in the Ross Sea, Antarctica, and exists as solitary cells and mucilaginous colonies that differ by several orders of magnitude in size. Recent studies with P. globosa suggested that colony formation and enl...

  19. Can inflation explain the second law of thermodynamics

    International Nuclear Information System (INIS)

    Page, D.N.; Pennsylvania State Univ., University Park

    1984-01-01

    The inflationary model of the universe can explain several of the cosmological conundra that are mysteries in the standard hot big bang model. Paul Davies has suggested that inflation can also explain the second law of thermodynamics, which describes the time asymmetry of the universe. Here several difficulties with this suggestion are noted showing how the present inflationary models must assume the arrow of time rather than explaining it. If the second law is formulated as a consequence of the hypothesis that there were no long-range spatial correlations in the initial state of the universe, it is shown how some of the cosmological conundra might be explained even without inflation. But if the ultimate explanation is to include inflation, three essential elements remain to be demonstrated which are listed. (author)

  20. A case study for effects of operational taxonomic units from intracellular endoparasites and ciliates on the eukaryotic phylogeny: phylogenetic position of the haptophyta in analyses of multiple slowly evolving genes.

    Directory of Open Access Journals (Sweden)

    Hisayoshi Nozaki

    Full Text Available Recent multigene phylogenetic analyses have contributed much to our understanding of eukaryotic phylogeny. However, the phylogenetic positions of various lineages within the eukaryotes have remained unresolved or in conflict between different phylogenetic studies. These phylogenetic ambiguities might have resulted from mixtures or integration from various factors including limited taxon sampling, missing data in the alignment, saturations of rapidly evolving genes, mixed analyses of short- and long-branched operational taxonomic units (OTUs, intracellular endoparasite and ciliate OTUs with unusual substitution etc. In order to evaluate the effects from intracellular endoparasite and ciliate OTUs co-analyzed on the eukaryotic phylogeny and simplify the results, we here used two different sets of data matrices of multiple slowly evolving genes with small amounts of missing data and examined the phylogenetic position of the secondary photosynthetic chromalveolates Haptophyta, one of the most abundant groups of oceanic phytoplankton and significant primary producers. In both sets, a robust sister relationship between Haptophyta and SAR (stramenopiles, alveolates, rhizarians, or SA [stramenopiles and alveolates] was resolved when intracellular endoparasite/ciliate OTUs were excluded, but not in their presence. Based on comparisons of character optimizations on a fixed tree (with a clade composed of haptophytes and SAR or SA, disruption of the monophyly between haptophytes and SAR (or SA in the presence of intracellular endoparasite/ciliate OTUs can be considered to be a result of multiple evolutionary reversals of character positions that supported the synapomorphy of the haptophyte and SAR (or SA clade in the absence of intracellular endoparasite/ciliate OTUs.

  1. Your Radiologist Explains Nuclear Medicine

    Medline Plus

    Full Text Available ... Disorders Video: The Basketball Game: An MRI Story Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Nuclear Medicine Transcript Welcome to Radiology Info dot org Hello! I’m Dr. Ramji ...

  2. Global marine plankton functional type biomass distributions : Phaeocystis spp

    NARCIS (Netherlands)

    Vogt, M.; O'Brien, C.; Peloquin, J.; Schoemann, V.; Breton, E.; Estrada, M.; Gibson, J.; Karentz, D.; van Leeuwe, M. A.; Stefels, J.; Widdicombe, C.; Peperzak, L.

    2012-01-01

    The planktonic haptophyte Phaeocystis has been suggested to play a fundamental role in the global biogeochemical cycling of carbon and sulphur, but little is known about its global biomass distribution. We have collected global microscopy data of the genus Phaeocystis and converted abundance data to

  3. Long-chain alkenones in Baltic Sea surface sediments: New insights

    NARCIS (Netherlands)

    Kaiser, J.; van der Meer, M.T.J.; Arz, H.W.

    2017-01-01

    C37 alkenones produced by certain haptophytes of the Isochrysidales are valuable sedimentary biomarkers used to estimate sea surface temperature (SST) in the open ocean. However, in coastal seas the role of salinity gradients on alkenone producing species and SST estimates is poorly known. Alkenones

  4. Your Radiologist Explains Nuclear Medicine

    Medline Plus

    Full Text Available ... by Image/Video Gallery Your Radiologist Explains Nuclear Medicine Transcript Welcome to Radiology Info dot org Hello! ... d like to talk to you about nuclear medicine. Nuclear medicine offers the potential to identify disease ...

  5. Your Radiologist Explains Nuclear Medicine

    Medline Plus

    Full Text Available ... An MRI Story Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Nuclear Medicine Transcript ... by a special camera and computer to create images of the inside of your body. If you’ ...

  6. Your Radiologist Explains Nuclear Medicine

    Medline Plus

    Full Text Available ... Sponsored by Image/Video Gallery Your Radiologist Explains Nuclear Medicine Transcript Welcome to Radiology Info dot org ... I’d like to talk to you about nuclear medicine. Nuclear medicine offers the potential to identify ...

  7. Explaining variation in nascent entrepreneurship

    NARCIS (Netherlands)

    A.J. van Stel (André); A.R.M. Wennekers (Sander); P. Reynolds (Paul); A.R. Thurik (Roy)

    2004-01-01

    textabstractThis paper aims at explaining cross-country variation in nascent entrepreneurship. Regression analysis is applied using various explanatory variables derived from three different approaches. We make use of the Global Entrepreneurship Monitor database, including nascent entrepreneurship

  8. Explaining nascent entrepreneurship across countries

    NARCIS (Netherlands)

    A.R. Thurik (Roy); A.J. van Stel (André); A.R.M. Wennekers (Sander); P. Reynolds (Paul)

    2003-01-01

    textabstractThis paper aims at explaining cross-country variation in nascent entrepreneurship. Regression analysis is applied using various explanatory variables derived from three different approaches. We make use of the Global Entrepreneurship Monitor database, including nascent entrepreneurship

  9. Association Between Osteogenesis and Inflammation During the Progression of Calcified Plaque Evaluated by 18F-Fluoride and 18F-FDG.

    Science.gov (United States)

    Li, Xiang; Heber, Daniel; Cal-Gonzalez, Jacobo; Karanikas, Georgios; Mayerhoefer, Marius E; Rasul, Sazan; Beitzke, Dietrich; Zhang, Xiaoli; Agis, Hermine; Mitterhauser, Markus; Wadsak, Wolfgang; Beyer, Thomas; Loewe, Christian; Hacker, Marcus

    2017-06-01

    18 F-FDG is the most widely validated PET tracer for the evaluation of atherosclerotic inflammation. Recently, 18 F-NaF has also been considered a potential novel biomarker of osteogenesis in atherosclerosis. We aimed to analyze the association between inflammation and osteogenesis at different stages of atherosclerosis, as well as the interrelationship between these 2 processes during disease progression. Methods: Thirty-four myeloma patients underwent 18 F-NaF and 18 F-FDG PET/CT examinations. Lesions were divided into 3 groups (noncalcified, mildly calcified, and severely calcified lesions) on the basis of calcium density as measured in Hounsfield units by CT. Tissue-to-background ratios were determined from PET for both tracers. The association between inflammation and osteogenesis during atherosclerosis progression was evaluated in 19 patients who had at least 2 examinations with both tracers. Results: There were significant correlations between the maximum tissue-to-background ratios of the 2 tracers (Spearman r = 0.5 [ P < 0.01]; Pearson r = 0.4 [ P < 0.01]) in the 221 lesions at baseline. The highest uptake of both tracers was observed in noncalcified lesions, but without any correlation between the tracers (Pearson r = 0.06; P = 0.76). Compared with noncalcified plaques, mildly calcified plaques showed concordant significantly lower accumulation, with good correlation between the tracers (Pearson r = 0.7; P < 0.01). In addition, enhanced osteogenesis-derived 18 F-NaF uptake and regressive inflammation-derived 18 F-FDG uptake were observed in severely calcified lesions (Pearson r = 0.4; P < 0.01). During follow-up, increased calcium density and increased mean 18 F-NaF uptake were observed, whereas mean 18 F-FDG uptake decreased. Most noncalcified (86%) and mildly calcified (81%) lesions and 47% of severely calcified lesions had concordant development of both vascular inflammation and osteogenesis. Conclusion: The combination of 18 F-NaF PET imaging and 18 F

  10. Data on analysis of coronary atherosclerosis on computed tomography and 18F-sodium fluoride positron emission tomography

    Directory of Open Access Journals (Sweden)

    Toshiro Kitagawa

    2017-08-01

    Full Text Available This article contains the data showing illustrative examples of plaque classification on coronary computed tomography angiography (CCTA and measurement of 18F-sodium fluoride (18F-NaF uptake in coronary atherosclerotic lesions on positron emission tomography (PET. We divided the lesions into one of three plaque types on CCTA (calcified plaque, non-calcified plaque, partially calcified plaque. Focal 18F-NaF uptake of each lesion was quantified using maximum tissue-to-background ratio. This article also provides a representative case with a non-calcified coronary plaque detected on CCTA and identified on 18F-NaF PET/non-contrast computed tomography based on a location of a vessel branch as a landmark. These complement the data reported by Kitagawa et al. (2017 [1].

  11. Astronomy Explained

    Science.gov (United States)

    North, Gerald

    Every year large numbers of people take up the study of astronomy, mostly at amateur level. There are plenty of elementary books on the market, full of colourful photographs, but lacking in proper explanations of how and why things are as they are. Many people eventually wish to go beyond the 'coffee-table book' stage and study this fascinating subject in greater depth. This book is written for them. In addition, many people sit for public examinations in this subject each year and this book is also intended to be of use to them. All the topics from the GCSE syllabus are covered here, with sample questions at the end of each chapter. Astronomy Explained provides a comprehensive treatment of the subject in more depth than is usually found in elementary works, and will be of interest to both amateur astronomers and students of astronomy.

  12. Journalism and Explaining News Content

    NARCIS (Netherlands)

    Albæk, E.; Skovsgaard, M.; de Vreese, C.H.; Nussbaum, J.F.

    Three models are presented to explain variation in news content. In the first model the explanation is based on the individual journalist, in the second model on the professional journalist, and in the third model on the organized journalist. The individual journalist model focuses on how the

  13. Explaining Infinite Series--An Exploration of Students' Images

    Science.gov (United States)

    Champney, Danielle Dawn

    2013-01-01

    This study uses self-generated representations (SGR)--images produced in the act of explaining--as a means of uncovering what university calculus students understand about infinite series convergence. It makes use of student teaching episodes, in which students were asked to explain to a peer what that student might have missed had they been…

  14. Can human error theory explain non-adherence?

    Science.gov (United States)

    Barber, Nick; Safdar, A; Franklin, Bryoney D

    2005-08-01

    To apply human error theory to explain non-adherence and examine how well it fits. Patients who were taking chronic medication were telephoned and asked whether they had been adhering to their medicine, and if not the reasons were explored and analysed according to a human error theory. Of 105 patients, 87 were contacted by telephone and they took part in the study. Forty-two recalled being non-adherent, 17 of them in the last 7 days; 11 of the 42 were intentionally non-adherent. The errors could be described by human error theory, and it explained unintentional non-adherence well, however, the application of 'rules' was difficult when considering mistakes. The consideration of error producing conditions and latent failures also revealed useful contributing factors. Human error theory offers a new and valuable way of understanding non-adherence, and could inform interventions. However, the theory needs further development to explain intentional non-adherence.

  15. Teachers mathematical communication profile in explaining subject matter

    Science.gov (United States)

    Umami, Rohmatul; Budayasa, I. Ketut; Suwarsono, St.

    2017-12-01

    This study aimed to see a teachers mathematical communication profile in explaining a subject matter. It is a qualitative research. A high-school junior teacher (i.e., a teacher with 1- to 5-year experience) teaching mathematics at X-Social Class was selected as the subject of this study. The data was collected by observing the teachers mathematical communication in explaining a given material (i.e., the rule of sine) in class and an in-depth interview would be organized respectively. The result showed that the junior teacher explained the subject matter in systematic, complete, fluent, and centered manner. In this case, she began with reminding students on the previous material related to the current material to be learned, informing the current learning objectives, and finally delivering the subject matter. To support her explanation, the teacher also provided some related information, led the students attention into the given material by asking them particular related questions, and did not use any confusing terms. However, the study found that some of high-school teachers still used less appropriate language in explaining materials.

  16. Can Marxism Explain America's Racism?

    Science.gov (United States)

    Willhelm, Sidney M.

    1980-01-01

    The Marxist interpretation of the Black experience in America has always had difficulty explaining various noneconomic aspects of racism. A perspective is needed that can blend racism as a variable in relationship with economic variables. To reach this perspective, the labor process within capitalism must be more fully understood. (Author/GC)

  17. Does market competition explain fairness?

    Science.gov (United States)

    Descioli, Peter

    2013-02-01

    The target article by Baumard et al. uses their previous model of bargaining with outside options to explain fairness and other features of human sociality. This theory implies that fairness judgments are determined by supply and demand but humans often perceive prices (divisions of surplus) in competitive markets to be unfair.

  18. Association of aortic valve calcification to the presence, extent, and composition of coronary artery plaque burden: from the Rule Out Myocardial Infarction using Computer Assisted Tomography (ROMICAT) trial.

    Science.gov (United States)

    Mahabadi, Amir A; Bamberg, Fabian; Toepker, Michael; Schlett, Christopher L; Rogers, Ian S; Nagurney, John T; Brady, Thomas J; Hoffmann, Udo; Truong, Quynh A

    2009-10-01

    Aortic valve calcification (AVC) is associated with cardiovascular risk factors and coronary artery calcification. We sought to determine whether AVC is associated with the presence and extent of overall plaque burden, as well as to plaque composition (calcified, mixed, and noncalcified). We examined 357 subjects (mean age 53 +/- 12 years, 61% male) who underwent contrast-enhanced electrocardiogram-gated 64-slice multidetector computed tomography from the ROMICAT trial for the assessment of presence and extent of coronary plaque burden according to the 17-coronary segment model and presence of AVC. Patients with AVC (n = 37, 10%) were more likely than those without AVC (n = 320, 90%) to have coexisting presence of any coronary plaque (89% vs 46%, P AVC had >3-fold increase odds of having any plaque (adjusted odds ratio [OR] 3.6, P = .047) and an increase of 2.5 segments of plaque (P AVC. When stratified by plaque composition, AVC was associated most with calcified plaque (OR 5.2, P = .004), then mixed plaque (OR 3.2, P = .02), but not with noncalcified plaque (P = .96). Aortic valve calcification is associated with the presence and greater extent of coronary artery plaque burden and may be part of the later stages of the atherosclerosis process, as its relation is strongest with calcified plaque, less with mixed plaque, and nonsignificant with noncalcified plaque. If AVC is present, consideration for aggressive medical therapy may be warranted.

  19. A model for diagnosing and explaining multiple disorders.

    Science.gov (United States)

    Jamieson, P W

    1991-08-01

    The ability to diagnose multiple interacting disorders and explain them in a coherent causal framework has only partially been achieved in medical expert systems. This paper proposes a causal model for diagnosing and explaining multiple disorders whose key elements are: physician-directed hypotheses generation, object-oriented knowledge representation, and novel explanation heuristics. The heuristics modify and link the explanations to make the physician aware of diagnostic complexities. A computer program incorporating the model currently is in use for diagnosing peripheral nerve and muscle disorders. The program successfully diagnoses and explains interactions between diseases in terms of underlying pathophysiologic concepts. The model offers a new architecture for medical domains where reasoning from first principles is difficult but explanation of disease interactions is crucial for the system's operation.

  20. Phytoplankton chemotaxonomy in the Atlantic sector of the Southern Ocean during late summer 2009

    CSIR Research Space (South Africa)

    Gibberd, M-J

    2013-08-01

    Full Text Available chlorophyll-a (chl-a) was 41.5 mg l(sup-1) and diatoms comprised 480% of biomass. Pigment signatures representative of haptophytes-8, indicative of Phaeocystis antarctica, were dominant near the ice shelf. Chl-a concentrations were 0.2–0.6 mg l(sup-1) between...

  1. Development and Assessment of Self-explaining Skills in College Chemistry Instruction

    Science.gov (United States)

    Villalta-Cerdas, Adrian

    The prevalent trend in chemistry instruction relies on what has been described as the classroom game. In this model, students take a passive role and the instructor does all the explaining (thinking), and learning is trivialized to knowing the correct answers (memorizing) and being able to produce them when prompted (regurgitating). The generation of explanations is central to scientific and technological development. In the process of figuring out explanations, the generation of inferences relies on the application of skills associated with scientific behaviors (e.g., analytical reasoning and critical thinking). The process of explanation generation causes a deeper analysis and revision of the scientific models, thus impacting the conceptual understanding of such models. Although the process of generating authentic explanations is closer to the experience of doing science, this process is seldom replicated in science instruction. Self-explaining refers to the generation of inferences about causal connections between objects and events. In science, this may be summarized as making sense of how and why actual or hypothetical phenomena take place. Research findings in educational psychology show that implementing activities that elicit self-explaining improves learning in general and specifically enhances authentic learning in the sciences. Research also suggests that self-explaining influences many aspects of cognition, including acquisition of problem-solving skills and conceptual understanding. Although the evidence that links self-explaining and learning is substantial, most of the research has been conducted in experimental settings. The purpose of this work was to advance knowledge in this area by investigating the effect of different self-explaining tasks on self-explaining behavior and the effect of engaging in different levels of self-explaining on learning chemistry concepts. Unlike most of the research in the field, this work did not focus on advancing

  2. Linear Algebra Thoroughly Explained

    CERN Document Server

    Vujičić, Milan

    2008-01-01

    Linear Algebra Thoroughly Explained provides a comprehensive introduction to the subject suitable for adoption as a self-contained text for courses at undergraduate and postgraduate level. The clear and comprehensive presentation of the basic theory is illustrated throughout with an abundance of worked examples. The book is written for teachers and students of linear algebra at all levels and across mathematics and the applied sciences, particularly physics and engineering. It will also be an invaluable addition to research libraries as a comprehensive resource book for the subject.

  3. Explaining Interaction Effects within and across Levels of Analysis

    DEFF Research Database (Denmark)

    Andersson, Ulf; Cuervo-Cazurra, Alvaro; Nielsen, Bo Bernhard

    2014-01-01

    Many manuscripts submitted to the Journal of International Business Studies propose an interaction effect in their models in an effort to explain the complexity and contingency of relationships across borders. In this article, we provide guidance on how best to explain the interaction effects...

  4. Bioimmuring late Cretaceous and Recent oysters : 'A view from within'

    NARCIS (Netherlands)

    Jagt, John W M; Neumann, Christian; Schulp, Anne S.

    2007-01-01

    Being obligate cementers, oysters (Ostreoidea), both fossil and Recent, often yield valuable information on their substrates, whether biotic/ abiotic, perishable or inert. By a process called bioimmuration, oyster shells may preserve lightly or non-calcified sessile organisms already present on the

  5. Students Explaining Science—Assessment of Science Communication Competence

    Science.gov (United States)

    Kulgemeyer, Christoph; Schecker, Horst

    2013-12-01

    Science communication competence (SCC) is an important educational goal in the school science curricula of several countries. However, there is a lack of research about the structure and the assessment of SCC. This paper specifies the theoretical framework of SCC by a competence model. We developed a qualitative assessment method for SCC that is based on an expert-novice dialog: an older student (explainer, expert) explains a physics phenomenon to a younger peer (addressee, novice) in a controlled test setting. The explanations are video-recorded and analysed by qualitative content analysis. The method was applied in a study with 46 secondary school students as explainers. Our aims were (a) to evaluate whether our model covers the relevant features of SCC, (b) to validate the assessment method and (c) to find characteristics of addressee-adequate explanations. A performance index was calculated to quantify the explainers' levels of competence on an ordinal scale. We present qualitative and quantitative evidence that the index is adequate for assessment purposes. It correlates with results from a written SCC test and a perspective taking test (convergent validity). Addressee-adequate explanations can be characterized by use of graphical representations and deliberate switches between scientific and everyday language.

  6. Tuned Normalization Explains the Size of Attention Modulations

    OpenAIRE

    Ni, Amy M.; Ray, Supratim; Maunsell, John H.R.

    2012-01-01

    The effect of attention on firing rates varies considerably within a single cortical area. The firing rate of some neurons is greatly modulated by attention while others are hardly affected. The reason for this variability across neurons is unknown. We found that the variability in attention modulation across neurons in area MT of macaques can be well explained by variability in the strength of tuned normalization across neurons. The presence of tuned normalization also explains a striking as...

  7. Explaining Support Vector Machines: A Color Based Nomogram.

    Directory of Open Access Journals (Sweden)

    Vanya Van Belle

    Full Text Available Support vector machines (SVMs are very popular tools for classification, regression and other problems. Due to the large choice of kernels they can be applied with, a large variety of data can be analysed using these tools. Machine learning thanks its popularity to the good performance of the resulting models. However, interpreting the models is far from obvious, especially when non-linear kernels are used. Hence, the methods are used as black boxes. As a consequence, the use of SVMs is less supported in areas where interpretability is important and where people are held responsible for the decisions made by models.In this work, we investigate whether SVMs using linear, polynomial and RBF kernels can be explained such that interpretations for model-based decisions can be provided. We further indicate when SVMs can be explained and in which situations interpretation of SVMs is (hitherto not possible. Here, explainability is defined as the ability to produce the final decision based on a sum of contributions which depend on one single or at most two input variables.Our experiments on simulated and real-life data show that explainability of an SVM depends on the chosen parameter values (degree of polynomial kernel, width of RBF kernel and regularization constant. When several combinations of parameter values yield the same cross-validation performance, combinations with a lower polynomial degree or a larger kernel width have a higher chance of being explainable.This work summarizes SVM classifiers obtained with linear, polynomial and RBF kernels in a single plot. Linear and polynomial kernels up to the second degree are represented exactly. For other kernels an indication of the reliability of the approximation is presented. The complete methodology is available as an R package and two apps and a movie are provided to illustrate the possibilities offered by the method.

  8. Measuring and explaining house price developments

    NARCIS (Netherlands)

    De Vries, P.

    2010-01-01

    This study discusses ways of measuring and explaining the development of house prices. The goal of the research underpinning this dissertation was to develop a methodological framework for studying these developments. This framework relates, first, to correcting for changes in the composition of

  9. Explaining social class differences in depression and well-being.

    Science.gov (United States)

    Stansfeld, S A; Head, J; Marmot, M G

    1998-01-01

    Work characteristics, including skill discretion and decision authority, explain most of the socioeconomic status gradient in well-being and depression in middle-aged British civil servants from the Whitehall II Study, London. Social support explained about one-third of the gradient, life events and material difficulties less than one-third. Socioeconomic status was measured by employment grade. Work characteristics were based on the Karasek model, social support was measured by the Close Persons Questionnaire, depression by the General Health Questionnaire and well-being by the Affect Balance Scale. Despite a small contribution from social selective factors measured by upward mobility, the psychosocial work environment explained most of the cross-sectional socioeconomic status gradient in well-being and depression.

  10. Do changes in connectivity explain desertification?

    Science.gov (United States)

    Desertification, broad-scale land degradation in drylands, is a major environmental hazard facing inhabitants of the world’s deserts as well as an important component of global change. There is no unifying framework that simply and effectively explains different forms of desertification. Here we arg...

  11. Explaining Disparities in Unemployment Dynamics

    OpenAIRE

    Karanassou, Marika; Snower, Dennis J.

    1993-01-01

    This paper attempts to explain disparities among the unemployment experiences of different OECD countries in terms of the `fragility' of the short-run unemployment equilibrium (the impact of labour market shocks on the short-run unemployment rate) and the lag structure of the employment determination, wage setting, and labour force participation decisions. The effects of this lag structure on unemployment dynamics are captured through two general measures of `unemployment persistence' (occurr...

  12. Assessment of carotid plaque composition using fast-kV switching dual-energy CT with gemstone detector: comparison with extracorporeal and virtual histology-intravascular ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Shinohara, Yuki; Kuya, Keita; Ohta, Yasutoshi; Fujii, Shinya; Ogawa, Toshihide [Tottori University, Division of Radiology, Department of Pathophysiological and Therapeutic Science, Faculty of Medicine, Yonago (Japan); Sakamoto, Makoto; Watanabe, Takashi [Tottori University, Division of Neurosurgery, Department of Neurological Sciences, Faculty of Medicine, Yonago (Japan); Kishimoto, Junichi; Iwata, Naoki [Tottori University Hospital, Division of Clinical Radiology, Yonago (Japan)

    2015-09-15

    The present study compares the applicability of CT carotid plaque imaging using effective Z maps using gemstone spectral imaging (GSI) with that of conventional extracorporeal carotid ultrasound (US) and virtual histology-intravascular ultrasound (VH-IVUS). We assessed stenosis in 31 carotid arteries of 30 patients. All patients underwent carotid CTA using GSI (Discovery CT750 HD, GE Healthcare). US and IVUS were examined with 25 and 8 vessels, respectively. We compared the effective Z values at noncalcified carotid plaque with the plaque components identified by US. We defined the plaque with low or low to iso intensity on US as vulnerable plaque and the plaque with iso, iso to high, and high intensity on US as stable plaque. We also performed visual assessment of color-coded effective Z maps in comparison with VH-IVUS and compared effective Z values with plaque components generated by VH-IVUS. The effective Z values at noncalcified carotid plaque were significantly lower for a group with vulnerable plaque, than with stable plaque on US (p < 0.05). Receiver operating curve analysis showed that AUC of effective Z values was 0.882 concerning the differentiation of these two groups on US. The interpretation of color-coded effective Z maps was essentially compatible with that of VH-IVUS for carotid plaque in all vessels. Effective Z values at noncalcified plaque showed significant negative correlation with the areas of fibro-fatty components generated by VH-IVUS (ρ = -0.874, p < 0.05). Effective Z maps generated by GSI can detect vulnerable carotid plaque materials. (orig.)

  13. Explaining convergence of oecd welfare states

    DEFF Research Database (Denmark)

    Schmitt, C.; Starke, Peter

    2011-01-01

    of conditional convergence helps to both better describe and explain the phenomenon. By applying error correction models, we examine conditional convergence of various types of social expenditure in 21 OECD countries between 1980 and 2005. Our empirical findings go beyond the existing literature in two respects...

  14. Explaining money creation by commercial banks

    DEFF Research Database (Denmark)

    Ravn, Ib

    2015-01-01

    Educators and economists concerned with monetary reform face the extraordinary challenge of explaining to the public and its elected representatives not only what a reformed system would look like, but also how the current system works. Centrally, the point that in a modern economy money is largely...... created by commercial banks, as explained by the Bank of England recently (McLeay, Radia & Thomas, 2014b), is often met with incredulity: “What do you mean, created?” This paper introduces five easy-to-grasp analogies that educators and reformers may use to convey key money-creation concepts to a lay...... audience. The analogies offered include (1) money as patches in an expandable patchwork quilt that covers a nation’s real assets, (2) the money supply as water in a bathtub with a faucet and a drain, (3) money understood as debt in a model economy run by schoolchildren, (4) the misleading concept of a bank...

  15. Phenotypic variance explained by local ancestry in admixed African Americans.

    Science.gov (United States)

    Shriner, Daniel; Bentley, Amy R; Doumatey, Ayo P; Chen, Guanjie; Zhou, Jie; Adeyemo, Adebowale; Rotimi, Charles N

    2015-01-01

    We surveyed 26 quantitative traits and disease outcomes to understand the proportion of phenotypic variance explained by local ancestry in admixed African Americans. After inferring local ancestry as the number of African-ancestry chromosomes at hundreds of thousands of genotyped loci across all autosomes, we used a linear mixed effects model to estimate the variance explained by local ancestry in two large independent samples of unrelated African Americans. We found that local ancestry at major and polygenic effect genes can explain up to 20 and 8% of phenotypic variance, respectively. These findings provide evidence that most but not all additive genetic variance is explained by genetic markers undifferentiated by ancestry. These results also inform the proportion of health disparities due to genetic risk factors and the magnitude of error in association studies not controlling for local ancestry.

  16. A model to explain human voice production

    Science.gov (United States)

    Vilas Bôas, C. S. N.; Gobara, S. T.

    2018-05-01

    This article presents a device constructed with low-cost material to demonstrate and explain voice production. It also provides a contextualized, interdisciplinary approach to introduce the study of sound waves.

  17. Explaining Teachers' Use of Textbooks

    Science.gov (United States)

    Reichenberg, Monica

    2016-01-01

    In educational systems without comprehensive systems for regulating textbooks, teachers can exert considerable influence on the use of textbooks. However, existing research has not yet identified the mechanisms of this use. Accordingly, the aim of this article is to examine and explain teachers' strategic use of textbooks. I administered a…

  18. Computed tomography of limy bile

    International Nuclear Information System (INIS)

    Yamamoto, Shinichiro; Kimoto, Masatoshi; Gunge, Nobuharu; Sano, Kaizo; Yamashita, Sachiko; Hirano, Yutaka

    1983-01-01

    The computed tomographic appearance of three cases of limy bile was reported. The CT findings consist of uniform high density within gallbladder, niveau formation between limy bile and noncalcified bile. Sagittal reconstruction of CT images was especially useful in the differentiation of limy bile and gallstones. (author)

  19. Intravascular ultrasound for iliac artery imaging. Clinical review

    DEFF Research Database (Denmark)

    Vogt, K G; Schroeder, T V

    2001-01-01

    IVUS is able to produce trans-sectional images of the iliac arteries at a high resolution. The three layered appearance of the arterial wall can be visualized. In the atherosclerotic diseased artery calcified plaques can be discerned from non-calcified plaques, and the distribution of the plaque...

  20. Machine learning and deep analytics for biocomputing: call for better explainability.

    Science.gov (United States)

    Petkovic, Dragutin; Kobzik, Lester; Re, Christopher

    2018-01-01

    The goals of this workshop are to discuss challenges in explainability of current Machine Leaning and Deep Analytics (MLDA) used in biocomputing and to start the discussion on ways to improve it. We define explainability in MLDA as easy to use information explaining why and how the MLDA approach made its decisions. We believe that much greater effort is needed to address the issue of MLDA explainability because of: 1) the ever increasing use and dependence on MLDA in biocomputing including the need for increased adoption by non-MLD experts; 2) the diversity, complexity and scale of biocomputing data and MLDA algorithms; 3) the emerging importance of MLDA-based decisions in patient care, in daily research, as well as in the development of new costly medical procedures and drugs. This workshop aims to: a) analyze and challenge the current level of explainability of MLDA methods and practices in biocomputing; b) explore benefits of improvements in this area; and c) provide useful and practical guidance to the biocomputing community on how to address these challenges and how to develop improvements. The workshop format is designed to encourage a lively discussion with panelists to first motivate and understand the problem and then to define next steps and solutions needed to improve MLDA explainability.

  1. Explaining focal points: Cognitive hierarchy theory versus team reasoning

    OpenAIRE

    Bardsley, Nicholas; Mehta, Judith; Starmer, Chris; Sugden, Robert

    2008-01-01

    This paper reports experimental tests of two alternative explanations of how players use focal points to select equilibria in one-shot coordination games. Cognitive hierarchy theory explains coordination as the result of common beliefs about players’ pre-reflective inclinations towards the relevant strategies; the theory of team reasoning explains it as the result of the players’ using a non-standard form of reasoning. We report two experiments. One finds strong support for team reasoning; th...

  2. Students' Development and Use of Models to Explain Electrostatic Interactions

    Science.gov (United States)

    Mayer, Kristin Elizabeth

    The National Research Council (2012) recently published A Framework for K-12 Science Education that describes a vision for science classrooms where students engage in three dimensions--scientific and engineering practices, crosscutting concepts, and disciplinary core ideas--to explain phenomena or observations they can make about the universe around them. This vision of science instruction is a significant shift from current classroom instruction. This dissertation provides detailed examples of how students developed and used models to build causal explanations of phenomena. I co-taught classes that focused on having students develop and revise models of electric fields and atomic structure using a curriculum that was designed to align with the three-dimensional vision of learning. I developed case studies of eleven students from these classes. I analyzed the students' responses and interviewed the students throughout the school year. By comparing and contrasting the analysis across the analysis of students' interviews, I identified four themes: 1) students could apply their ideas to explain novel and abstract phenomena; 2) students struggled to connect changes in their atomic models to evidence, but ended up with dynamic models of atomic structure that they could apply to explain phenomena; 3) students developed models of atomic structure that they applied to explain phenomena, but they did not use models of electric fields in this way; and 4) too much focus on details interfered with students' ability to apply their models to explain new phenomena. This dissertation highlights the importance of focusing on phenomena in classrooms that aim at aligning with three-dimensional learning. Students struggled to focus on specific content and apply their ideas to explain phenomena at the same time. In order to apply ideas to new context, students had to shift their focus from recalling ideas to applying the ideas they do have. A focus on phenomena allowed students to show

  3. Critical Factors Explaining the Leadership Performance of High-Performing Principals

    Science.gov (United States)

    Hutton, Disraeli M.

    2018-01-01

    The study explored critical factors that explain leadership performance of high-performing principals and examined the relationship between these factors based on the ratings of school constituents in the public school system. The principal component analysis with the use of Varimax Rotation revealed that four components explain 51.1% of the…

  4. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... Disorders Video: The Basketball Game: An MRI Story Radiology and You Sponsored by Image/Video Gallery Your ... Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot org Hello, I’m Dr. Elliot ...

  5. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... An MRI Story Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography ( ... posted: How to Obtain and Share Your Medical Images Movement Disorders Video: The Basketball Game: An MRI ...

  6. Using Expectancy Theory to Explain Performance Appraisal ...

    African Journals Online (AJOL)

    pc

    2018-03-05

    Mar 5, 2018 ... appraisal conducting style, the relation between the performance appraisal system and task ... the article first explains the theory model which is based expectancy theory. II. ... which in return lead to rewards. According to [12],.

  7. Explorers Presentation: Explaining the Tides to Children

    OpenAIRE

    Institute, Marine

    2015-01-01

    Explaining the tides to children Presentation includes information about: Orbits of the Earth, Moon and Sun; Moon phases and the lunar cycle; Gravity; Gravity and the tide; Types of tides; The tides and me!; Tide tables; Extra insight

  8. Explaining the Allocation of Regional Structural Funds

    DEFF Research Database (Denmark)

    Charron, Nicholas

    2016-01-01

    What regional factors can explain the heterogeneity in Structural Funds distribution to European Union regions? Past studies have shown that aside from the level of economic development and rates of unemployment, other political, and economic factors systematically explain why certain European...... Union regions receive greater funding than others, in particular where there is room for bargaining. In this article, a novel theory is posited which argues that the determination of Structural Funds is based on an interaction between a region’s formal institutions (the level of a regional autonomy......) and informal institutions (its level of quality of government). In cases of low regional autonomy, member states and European Union level actors prefer to allocate greater levels of Funds to regions with lower quality of government in order to increase cohesion. Yet in cases of high regional autonomy, risks...

  9. The role of social factors in explaining crime

    Directory of Open Access Journals (Sweden)

    Siti Nur Zahara HAMZAH

    2013-06-01

    Full Text Available Utilizing Malaysia data from 1973 to 2008, the study reveals that crime can be influenced by population, fertility, unemployment, and GDP in either the long-run or short-run period. This study also further analysed beyond sample estimations of the variables involved and found that although violent crime can be explained in the short-run only from the VECM analysis, it is found to be explained by other explanatory variables in the long-run of beyond sample for at least 50 years ahead. It is important for policy makers to focus in both social structure and economic conditions to help prevent crime in the long-run.

  10. Topology Explains Why Automobile Sunshades Fold Oddly

    Science.gov (United States)

    Feist, Curtis; Naimi, Ramin

    2009-01-01

    Automobile sunshades always fold into an "odd" number of loops. The explanation why involves elementary topology (braid theory and linking number, both explained in detail here with definitions and examples), and an elementary fact from algebra about symmetric group.

  11. Does Asset Allocation Policy Explain 40, 90, 100 Percent of Performance?

    OpenAIRE

    Roger G. Ibbotson; Paul D. Kaplan

    2001-01-01

    Does asset allocation policy explain 40 percent, 90 percent, or 100 percent of performance? According to some well-known studies, more than 90 percent of the variability of a typical plan sponsor's performance over time is attributable to asset allocation. However, few people want to explain variability over time. Instead, an analyst might want to know how important it is in explaining the differences in return from one fund to another, or what percentage of the level of a typical fund's retu...

  12. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot ... I’d like to talk with you about magnetic resonance angiography, or as it’s commonly known, MRA. MRA ...

  13. Explaining the Evolution of Poverty

    DEFF Research Database (Denmark)

    Arndt, Channing; Hussain, Azhar; Jones, Edward Samuel

    2012-01-01

    We provide a comprehensive approach for analyzing the evolution of poverty using Mozambique as a case study. Bringing together data from disparate sources, we develop a novel “back-casting” framework that links a dynamic computable general equilibrium model to a micro-simulation poverty module....... This framework provides a new approach to explaining and decomposing the evolution of poverty, as well as to examining rigorously the coherence between poverty, economic growth, and inequality outcomes. Finally, various simple but useful and rarely-applied approaches to considering regional changes in poverty...

  14. Explaining subsidiaries' knowledge-diffusion behaviours within MNEs

    NARCIS (Netherlands)

    Ho, H.C.

    2007-01-01

    This study explores how subsidiaries can contribute their advantages for the whole MNE in knowledge diffusion processes. The research model includes both organisational factors and local resources in a host country to explain subsidiaries' diffusion behaviours. We carried out an online survey for

  15. How brain and neuronal networks explain human reality

    Directory of Open Access Journals (Sweden)

    Javier Monserrat

    2017-02-01

    Full Text Available How is human reality presented to us in phenomenological experience? It is the one we see daily in our personal and social life. We are made of matter, we are part of the evolutionary universe. In addition, a psychic life is formed in us: sensation, a system of perceptions, an integrated consciousness, a condition of psychological subject; We produce knowledge, emotions, motivations; But, above all, we have a mind that rationally moves and installs us into a world of human emotions; This emotional reason lies at the base of the search for the truth of the universe, the meaning of life and the moral responsibility, in personal and social life. Our human reality is, therefore, a personal reality. We are persons. Now, how does science, neurology, explain today the fact that our human reality possesses these properties that give us the personal condition? This should be able to be explained (this is the initial assumption from the physical-biological world. Now, in particular, how does science make it possible to explain that evolution has produced us in our condition of ratio-emotional persons? That is, what is the physical support that makes intelligible the psycho-bio-physical ontology that evolutionarily produces our personal phenomenological experience? This is, ultimately, still the fundamental question of human sciences. What science, namely neurology, must explain (that is, know the causes that have produced it is obvious: the fact of our sensibility-consciousness, our condition of psychic subjects, knowledge and emotional reason that have emerged in the universe; In such a way that, once the emotional reason emerges, it leads by itself to constitute the rational activity and the emotions of the human person aimed at building the meaning of his life. These are the issues we address in this article.

  16. Association between diabetes and different components of coronary atherosclerotic plaque burden as measured by coronary multidetector computed tomography.

    Science.gov (United States)

    Yun, Chun-Ho; Schlett, Christopher L; Rogers, Ian S; Truong, Quynh A; Toepker, Michael; Donnelly, Patrick; Brady, Thomas J; Hoffmann, Udo; Bamberg, Fabian

    2009-08-01

    The aim of the study was to assess differences in the presence, extent, and composition of coronary atherosclerotic plaque burden as detected by coronary multidetector computed tomography (MDCT) between patients with and without diabetes mellitus. We compared coronary atherosclerotic plaques (any plaque, calcified [CAP], non-calcified [NCAP, and mixed plaque [MCAP

  17. Quantifying explainable discrimination and removing illegal discrimination in automated decision making

    KAUST Repository

    Kamiran, Faisal; Žliobaite, Indre; Calders, Toon

    2012-01-01

    discrimination and do not take into account that part of the discrimination may be explainable by other attributes. For example, in a job application, the education level of a job candidate could be such an explainable attribute. If the data contain many highly

  18. Children's Theories and the Drive to Explain

    Science.gov (United States)

    Schwitzgebel, Eric

    Debate has been growing in developmental psychology over how much the cognitive development of children is like theory change in science. Useful debate on this topic requires a clear understanding of what it would be for a child to have a theory. I argue that existing accounts of theories within philosophy of science and developmental psychology either are less precise than is ideal for the task or cannot capture everyday theorizing of the sort that children, if they theorize, must do. I then propose an account of theories that ties theories and explanation very closely together, treating theories primarily as products of a drive to explain. I clarify some of the positions people have taken regarding the theory theory of development, and I conclude by proposing that psychologists interested in the ''theory theory'' look for patterns of affect and arousal in development that would accompany the existence of a drive to explain.

  19. HIV As Trojan Exosome: Immunological Paradox Explained?

    Science.gov (United States)

    Hildreth, James E K

    2017-01-01

    The HIV pandemic is still a major global challenge, despite the widespread availability of antiretroviral drugs. An effective vaccine would be the ideal approach to bringing the pandemic to an end. However, developing an effective HIV vaccine has proven to be an elusive goal. Three major human HIV vaccine trials revealed a strong trend toward greater risk of infection among vaccine recipients versus controls. A similar observation was made in a macaque SIV vaccine study. The mechanism explaining this phenomenon is not known. Here, a model is presented that may explain the troubling results of vaccine studies and an immunological paradox of HIV pathogenesis: preferential infection of HIV-specific T cells. The central hypothesis of this perspective is that as "Trojan exosomes" HIV particles can directly activate HIV-specific T cells enhancing their susceptibility to infection. Understanding the biology of HIV as an exosome may provide insights that enable novel approaches to vaccine development.

  20. Explaining the VET Applied Research Developmental Framework

    Science.gov (United States)

    Simon, Linda; Beddie, Francesca M.

    2017-01-01

    This document explains the VET Applied Research Developmental Framework, created as part of a project that explored how the vocational education and training (VET) sector could broaden its engagement in Australia's research and development (R&D) and innovation systems. Achieving this engagement will rely significantly on building the…

  1. Quantifying explainable discrimination and removing illegal discrimination in automated decision making

    KAUST Repository

    Kamiran, Faisal

    2012-11-18

    Recently, the following discrimination-aware classification problem was introduced. Historical data used for supervised learning may contain discrimination, for instance, with respect to gender. The question addressed by discrimination-aware techniques is, given sensitive attribute, how to train discrimination-free classifiers on such historical data that are discriminative, with respect to the given sensitive attribute. Existing techniques that deal with this problem aim at removing all discrimination and do not take into account that part of the discrimination may be explainable by other attributes. For example, in a job application, the education level of a job candidate could be such an explainable attribute. If the data contain many highly educated male candidates and only few highly educated women, a difference in acceptance rates between woman and man does not necessarily reflect gender discrimination, as it could be explained by the different levels of education. Even though selecting on education level would result in more males being accepted, a difference with respect to such a criterion would not be considered to be undesirable, nor illegal. Current state-of-the-art techniques, however, do not take such gender-neutral explanations into account and tend to overreact and actually start reverse discriminating, as we will show in this paper. Therefore, we introduce and analyze the refined notion of conditional non-discrimination in classifier design. We show that some of the differences in decisions across the sensitive groups can be explainable and are hence tolerable. Therefore, we develop methodology for quantifying the explainable discrimination and algorithmic techniques for removing the illegal discrimination when one or more attributes are considered as explanatory. Experimental evaluation on synthetic and real-world classification datasets demonstrates that the new techniques are superior to the old ones in this new context, as they succeed in

  2. Towards explaining the speed of k-means

    NARCIS (Netherlands)

    Manthey, Bodo; van de Pol, Jan Cornelis; Raamsdonk, F.; Stoelinga, Mariëlle Ida Antoinette

    2011-01-01

    The $k$-means method is a popular algorithm for clustering, known for its speed in practice. This stands in contrast to its exponential worst-case running-time. To explain the speed of the $k$-means method, a smoothed analysis has been conducted. We sketch this smoothed analysis and a generalization

  3. Firm Performance and Comply or Explain Disclosure in Corporate Governance

    DEFF Research Database (Denmark)

    Rose, Caspar

    2016-01-01

    This study investigates the degree of Danish firm adherence to the Danish Code of Corporate Governance and analyzes if a higher degree of comply or explain disclosure is related to firm performance. This article formulates a methodology for quantifying the degree of comply or explain disclosure...... there is no impact on performance when increasing compliance with the recommendations on risk management and internal controls. This article demonstrates that these three areas are the ones where Danish firms show the lowest degree of comply or explain disclosure, although the overall adherence to the Danish code...... that soft law may be an efficient way of increasing the quality of corporate governance among listed firms. However, in order to strengthen investor confidence, national code authorities/committees should be more active in penalizing poor explanations as well as cases where firms wrongfully state...

  4. Adaptive hatching hypotheses do not explain asynchronous ...

    African Journals Online (AJOL)

    At the core of the suite of adaptive hatching hypotheses advanced to explain asynchronous hatching in birds is the assumption that if food is not limited then all the hatchlings will develop normally to adulthood. In this study Brown-headed Parrot Poicephalus cryptoxanthus chicks were hand fed and weighed on a daily basis.

  5. Spatially tuned normalization explains attention modulation variance within neurons.

    Science.gov (United States)

    Ni, Amy M; Maunsell, John H R

    2017-09-01

    Spatial attention improves perception of attended parts of a scene, a behavioral enhancement accompanied by modulations of neuronal firing rates. These modulations vary in size across neurons in the same brain area. Models of normalization explain much of this variance in attention modulation with differences in tuned normalization across neurons (Lee J, Maunsell JHR. PLoS One 4: e4651, 2009; Ni AM, Ray S, Maunsell JHR. Neuron 73: 803-813, 2012). However, recent studies suggest that normalization tuning varies with spatial location both across and within neurons (Ruff DA, Alberts JJ, Cohen MR. J Neurophysiol 116: 1375-1386, 2016; Verhoef BE, Maunsell JHR. eLife 5: e17256, 2016). Here we show directly that attention modulation and normalization tuning do in fact covary within individual neurons, in addition to across neurons as previously demonstrated. We recorded the activity of isolated neurons in the middle temporal area of two rhesus monkeys as they performed a change-detection task that controlled the focus of spatial attention. Using the same two drifting Gabor stimuli and the same two receptive field locations for each neuron, we found that switching which stimulus was presented at which location affected both attention modulation and normalization in a correlated way within neurons. We present an equal-maximum-suppression spatially tuned normalization model that explains this covariance both across and within neurons: each stimulus generates equally strong suppression of its own excitatory drive, but its suppression of distant stimuli is typically less. This new model specifies how the tuned normalization associated with each stimulus location varies across space both within and across neurons, changing our understanding of the normalization mechanism and how attention modulations depend on this mechanism. NEW & NOTEWORTHY Tuned normalization studies have demonstrated that the variance in attention modulation size seen across neurons from the same cortical

  6. Cascading effects of ocean acidification in a rocky subtidal community.

    Directory of Open Access Journals (Sweden)

    Valentina Asnaghi

    Full Text Available Temperate marine rocky habitats may be alternatively characterized by well vegetated macroalgal assemblages or barren grounds, as a consequence of direct and indirect human impacts (e.g. overfishing and grazing pressure by herbivorous organisms. In future scenarios of ocean acidification, calcifying organisms are expected to be less competitive: among these two key elements of the rocky subtidal food web, coralline algae and sea urchins. In order to highlight how the effects of increased pCO2 on individual calcifying species will be exacerbated by interactions with other trophic levels, we performed an experiment simultaneously testing ocean acidification effects on primary producers (calcifying and non-calcifying algae and their grazers (sea urchins. Artificial communities, composed by juveniles of the sea urchin Paracentrotus lividus and calcifying (Corallina elongata and non-calcifying (Cystoseira amentacea var stricta, Dictyota dichotoma macroalgae, were subjected to pCO2 levels of 390, 550, 750 and 1000 µatm in the laboratory. Our study highlighted a direct pCO2 effect on coralline algae and on sea urchin defense from predation (test robustness. There was no direct effect on the non-calcifying macroalgae. More interestingly, we highlighted diet-mediated effects on test robustness and on the Aristotle's lantern size. In a future scenario of ocean acidification a decrease of sea urchins' density is expected, due to lower defense from predation, as a direct consequence of pH decrease, and to a reduced availability of calcifying macroalgae, important component of urchins' diet. The effects of ocean acidification may therefore be contrasting on well vegetated macroalgal assemblages and barren grounds: in the absence of other human impacts, a decrease of biodiversity can be predicted in vegetated macroalgal assemblages, whereas a lower density of sea urchin could help the recovery of shallow subtidal rocky areas affected by overfishing from

  7. Cascading effects of ocean acidification in a rocky subtidal community.

    Science.gov (United States)

    Asnaghi, Valentina; Chiantore, Mariachiara; Mangialajo, Luisa; Gazeau, Frédéric; Francour, Patrice; Alliouane, Samir; Gattuso, Jean-Pierre

    2013-01-01

    Temperate marine rocky habitats may be alternatively characterized by well vegetated macroalgal assemblages or barren grounds, as a consequence of direct and indirect human impacts (e.g. overfishing) and grazing pressure by herbivorous organisms. In future scenarios of ocean acidification, calcifying organisms are expected to be less competitive: among these two key elements of the rocky subtidal food web, coralline algae and sea urchins. In order to highlight how the effects of increased pCO2 on individual calcifying species will be exacerbated by interactions with other trophic levels, we performed an experiment simultaneously testing ocean acidification effects on primary producers (calcifying and non-calcifying algae) and their grazers (sea urchins). Artificial communities, composed by juveniles of the sea urchin Paracentrotus lividus and calcifying (Corallina elongata) and non-calcifying (Cystoseira amentacea var stricta, Dictyota dichotoma) macroalgae, were subjected to pCO2 levels of 390, 550, 750 and 1000 µatm in the laboratory. Our study highlighted a direct pCO2 effect on coralline algae and on sea urchin defense from predation (test robustness). There was no direct effect on the non-calcifying macroalgae. More interestingly, we highlighted diet-mediated effects on test robustness and on the Aristotle's lantern size. In a future scenario of ocean acidification a decrease of sea urchins' density is expected, due to lower defense from predation, as a direct consequence of pH decrease, and to a reduced availability of calcifying macroalgae, important component of urchins' diet. The effects of ocean acidification may therefore be contrasting on well vegetated macroalgal assemblages and barren grounds: in the absence of other human impacts, a decrease of biodiversity can be predicted in vegetated macroalgal assemblages, whereas a lower density of sea urchin could help the recovery of shallow subtidal rocky areas affected by overfishing from barren grounds to

  8. Coronary heart disease risk assessment and characterization of coronary artery disease using coronary CT angiography: comparison of asymptomatic and symptomatic groups

    International Nuclear Information System (INIS)

    Hwang, Y.; Kim, Y.; Chung, I.-M.; Ryu, J.; Park, H.

    2010-01-01

    Aim: To evaluate the prevalence of coronary artery disease (CAD) in relation to risk of coronary heart disease (CHD) and assess plaque characteristics from coronary computed tomography (CT) angiography in asymptomatic and symptomatic patients. Materials and methods: Three hundred and ninety consecutive patients [asymptomatic group, n = 138; symptomatic group (atypical or non-anginal chest pain), n = 252] were retrospectively enrolled. They were subsequently classified into three CHD risk categories, based on the National Cholesterol Education Program guidelines, and 10 year risks of coronary events were calculated using Framingham risk score. CT was evaluated for stenosis, plaque composition, and coronary calcium scores. Results: CAD was observed in 42% of the asymptomatic group and 62% of the symptomatic group. In the former, the prevalence of CAD in low-, moderate- and high-risk subgroups was 21.4, 47.4 and 65%, respectively, and was 33.3, 74.4, and 72.4% in the symptomatic group. Framingham 10-year risks of coronary events were significantly higher in patients with CAD than in normal participants, and receiver operating characteristics curves showed that discriminatory power was poor in the asymptomatic group and symptomatic men, and good in symptomatic women. Of the participants in the asymptomatic group, 12% exhibited only non-calcified plaques and of the symptomatic group, 7% exhibited only non-calcified plaques. The coronary calcium score was significantly higher for significant stenosis than for non-significant stenosis in both groups. Conclusions: The prevalence of CAD was not negligible even in subgroups with low-to-moderate CHD risk. Additionally, the Framingham risk score was effective for predicting CAD only in symptomatic women. Coronary calcium scores correlated with significant stenosis; however, a sizeable percentage of both groups had only non-calcified plaques.

  9. Influence of convolution filtering on coronary plaque attenuation values: observations in an ex vivo model of multislice computed tomography coronary angiography

    International Nuclear Information System (INIS)

    Cademartiri, Filippo; Palumbo, Alessandro; La Grutta, Ludovico; Runza, Giuseppe; Maffei, Erica; Mollet, Nico R.; Hamers, Ronald; Bruining, Nico; Bartolotta, Tommaso V.; Midiri, Massimo; Somers, Pamela; Knaapen, Michiel; Verheye, Stefan

    2007-01-01

    Attenuation variability (measured in Hounsfield Units, HU) of human coronary plaques using multislice computed tomography (MSCT) was evaluated in an ex vivo model with increasing convolution kernels. MSCT was performed in seven ex vivo left coronary arteries sunk into oil followingthe instillation of saline (1/∞) and a 1/50 solution of contrast material (400 mgI/ml iomeprol). Scan parameters were: slices/collimation, 16/0.75 mm; rotation time, 375 ms. Four convolution kernels were used: b30f-smooth, b36f-medium smooth, b46f-medium and b60f-sharp. An experienced radiologist scored for the presence of plaques and measured the attenuation in lumen, calcified and noncalcified plaques and the surrounding oil. The results were compared by the ANOVA test and correlated with Pearson's test. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. The mean attenuation values were significantly different between the four filters (p < 0.0001) in each structure with both solutions. After clustering for the filter, all of the noncalcified plaque values (20.8 ± 39.1, 14.2 ± 35.8, 14.0 ± 32.0, 3.2 ± 32.4 HU with saline; 74.7 ± 66.6, 68.2 ± 63.3, 66.3 ± 66.5, 48.5 ± 60.0 HU in contrast solution) were significantly different, with the exception of the pair b36f-b46f, for which a moderate-high correlation was generally found. Improved SNRs and CNRs were achieved by b30f and b46f. The use of different convolution filters significantly modified the attenuation values, while sharper filtering increased the calcified plaque attenuation and reduced the noncalcified plaque attenuation. (orig.)

  10. Do sector-specific shocks explain aggregate fluctuations?

    DEFF Research Database (Denmark)

    Busato, Francesco; Girardi, Alessandro; Argentiero, Amedeo

    -sector productivity fluctuations.(ii) Cross-sector technology shocks have very little explanatory power on productivity andemployment, while cross-sector non-technology shocks explain more than 60 percent of employmentthat is reallocated across sector; this suggests that the shocks’ transmission mechanism....... Thenon-durable sector may follow a standard RBC model, while the durable sector should incorporateconsumption habit formation....

  11. Explaining probalistic risk assessment in common language

    International Nuclear Information System (INIS)

    Wong, J.W.

    1994-01-01

    Probabilistic human health risk assessment is explained in ordinary language using a hypothetical example and the ingestion equation from EPA's Risk Assessment Guidance for Superfund. A section on understanding probabilities and probability distributions used in a Monte Carlo simulation is included as well as an appendix showing the computer run and the technical assumptions behind it

  12. Can the inherence heuristic explain vitalistic reasoning?

    Science.gov (United States)

    Bastian, Brock

    2014-10-01

    Inherence is an important component of psychological essentialism. By drawing on vitalism as a way in which to explain this link, however, the authors appear to conflate causal explanations based on fixed features with those based on general causal forces. The disjuncture between these two types of explanatory principles highlights potential new avenues for the inherence heuristic.

  13. Explaining Violence in Sierra Leone's Civil War

    African Journals Online (AJOL)

    Explaining the violence of civil war is never a simple task for the scholar. In the case of the Sierra Leone, paradoxically, the task has in some ways been rendered more difficult by the sheer variety of compelling scholarship on the question. This paper seeks to identify the most useful of the explanations offered thus far, and ...

  14. The future of the northeast Atlantic benthic flora in a high CO2 world.

    Science.gov (United States)

    Brodie, Juliet; Williamson, Christopher J; Smale, Dan A; Kamenos, Nicholas A; Mieszkowska, Nova; Santos, Rui; Cunliffe, Michael; Steinke, Michael; Yesson, Christopher; Anderson, Kathryn M; Asnaghi, Valentina; Brownlee, Colin; Burdett, Heidi L; Burrows, Michael T; Collins, Sinead; Donohue, Penelope J C; Harvey, Ben; Foggo, Andrew; Noisette, Fanny; Nunes, Joana; Ragazzola, Federica; Raven, John A; Schmidt, Daniela N; Suggett, David; Teichberg, Mirta; Hall-Spencer, Jason M

    2014-07-01

    Seaweed and seagrass communities in the northeast Atlantic have been profoundly impacted by humans, and the rate of change is accelerating rapidly due to runaway CO2 emissions and mounting pressures on coastlines associated with human population growth and increased consumption of finite resources. Here, we predict how rapid warming and acidification are likely to affect benthic flora and coastal ecosystems of the northeast Atlantic in this century, based on global evidence from the literature as interpreted by the collective knowledge of the authorship. We predict that warming will kill off kelp forests in the south and that ocean acidification will remove maerl habitat in the north. Seagrasses will proliferate, and associated epiphytes switch from calcified algae to diatoms and filamentous species. Invasive species will thrive in niches liberated by loss of native species and spread via exponential development of artificial marine structures. Combined impacts of seawater warming, ocean acidification, and increased storminess may replace structurally diverse seaweed canopies, with associated calcified and noncalcified flora, with simple habitats dominated by noncalcified, turf-forming seaweeds.

  15. Crystalline Ultrastructures, Inflammatory Elements, and Neoangiogenesis Are Present in Inconspicuous Aortic Valve Tissue

    Directory of Open Access Journals (Sweden)

    P. Dorfmüller

    2010-01-01

    Full Text Available Morbidity from calcific aortic valve disease (CAVD is increasing. Recent studies suggest early reversible changes involving inflammation and neoangiogenesis. We hypothesized that microcalcifications, chemokines, and growth factors are present in unaffected regions of calcific aortic valves. We studied aortic valves from 4 patients with CAVD and from 1 control, using immunohistochemistry, scanning electron microscopy, and infrared spectrography. We revealed clusters of capillary neovessels in calcified (ECC, to a lesser extent in noncalcified (ECN areas. Endothelial cells proved constant expression of SDF-1 in ECC, ECN, and endothelial cells from valvular surface (ECS. Its receptor CXCR4 was expressed in ECC. IL-6 expression correlated with CXCR4 staining and presence of lymphocytes. VEGF was expressed by ECS, its receptor by ECC and ECN. Crystalline ultrastructures were found on the surface of histologically noncalcified areas (HNCAs, spectrography revealed calcium hydroxylapatite. Our results demonstrate that crystalline ultrastructures are present in HNCAs, undergoing neoangiogenesis in an inflammatory context. These alterations could be an early witness of disease and an opening to therapy.

  16. WAP explained

    International Nuclear Information System (INIS)

    Kaiser, M.J.; Pulsipher, A.G.

    2004-01-01

    The Weatherization Assistance Program (WAP) is a federal block grant program administered by all 50 states and the District of Columbia through community action agencies, state energy offices, local government, and other nonprofit organizations to provide weatherization services to eligible households. The WAP was established in 1976 to increase the energy efficiency, reduce the energy expenditures, and improve the health and safety of low-income households, especially those households that are particularly vulnerable such as families with children, persons with disabilities, and the elderly. The manner in which WAP funds have been allocated to states, however, has been a contentious issue since the inception of the program. Southern states have argued that too much of the federal funding goes to cold-climate and rural states. Northern states disagree. In 1990, Congress amended the Energy Conservation and Production Act and required the Department of Energy to develop a new funding formula. The Department of Energy currently uses a three-factor formula developed in 1995 in conjunction with a two-factor formula developed in 1977 and a hold-harmless provision to allocate WAP funding. The purpose of this paper is to explain the WAP allocation mechanism and the assumptions associated with the 1977 and the 1995 funding formula. The factors that compose each funding formula are critically assessed and various implementation issues are reviewed, including the selection of the trigger point and program capacity levels. It is not possible to define the need for weatherization assistance objectively and in a unique manner, and this ambiguity is the main reason why the WAP allocation mechanism is expected to remain a lively topic of debate and contention

  17. IEE wiring regulations explained and illustrated

    CERN Document Server

    Scaddan, Brian

    2013-01-01

    The IEE Wiring Regulations Explained and Illustrated, Second Edition discusses the recommendations of the IEE Regulations for the Electrical Equipment of Buildings for the safe selection or erection of wiring installations. The book emphasizes earthing, bonding, protection, and circuit design of electrical wirings. The text reviews the fundamental requirements for safety, earthing systems, the earth fault loop impedance, and supplementary bonding. The book also describes the different types of protection, such as protection against mechanical damage, overcurrent, under voltage (which prevents

  18. k-essence explains a Lorentz violation experiment

    International Nuclear Information System (INIS)

    Li Miao; Pang Yi; Wang Yi

    2009-01-01

    Recently, a state of the art experiment shows evidence for Lorentz violation in the gravitational sector. To explain this experiment, we investigate a spontaneous Lorentz violation scenario with a generalized scalar field. We find that when the scalar field is nonminimally coupled to gravity, the Lorentz violation induces a deformation in the Newtonian potential along the direction of Lorentz violation.

  19. The natural selection of metabolism explains curvature in allometric scaling

    OpenAIRE

    Witting, Lars

    2016-01-01

    I simulate the evolution of metabolism and mass to explain the curvature in the metabolic allometry for placental and marsupial mammals. I assume that the release of inter-specific competition by the extinction of dinosaurs 65 million years ago made it possible for each clade to diversity into a multitude of species across a wide range of niches. The natural selection of metabolism and mass was then fitted to explain the maximum observed body masses over time, as well as the current inter-spe...

  20. Explaining the judicial independence of international courts: a comparative analysis

    DEFF Research Database (Denmark)

    Beach, Derek

    What factors allow some international courts (ICs) to rule against the express preferences of powerful member states, whereas others routinely defer to governments? While judicial independence is not the only factor explaining the strength of a given international institution, it is a necessary...... condition. The paper first develops three sets of competing explanatory variables that potentially can explain variations in the judicial independence of ICs. The causal effects of these explanatory variables upon variance in judicial independence are investigated in a comparative analysis of the ACJ, ECJ...

  1. Explaining  the choice of accounting standards in municipal corporations

    OpenAIRE

    Collin, Sven-Olof; Tagesson, Torbjörn; Andersson, Anette; Cato, Josefine; Hansson, Karin

    2004-01-01

    Positive  accounting  theory  (PAT)  tries  to  explain  corporations’  choices  of accounting standards. Empirical research in this field has been focused on the choices  made by large, listed corporations. We challenge this grounding through extending the empirical domain by testing PAT on Swedish municipal corporations. In  order to be able to explain the choice of accounting standards in municipal corporations, PAT has to be complemented by institutional factors that can consider the   fo...

  2. Cultural values: can they explain self-reported health?

    NARCIS (Netherlands)

    Roudijk, B.; Donders, R.; Stalmeier, P.F.

    2017-01-01

    PURPOSE: Self-reported health (SRH) is a measure widely used in health research and population studies. Differences in SRH have been observed between countries and cultural values have been hypothesized to partly explain such differences. Cultural values can be operationalized by two cultural

  3. From laggard to leader: Explaining offshore wind developments in the UK

    International Nuclear Information System (INIS)

    Kern, Florian; Smith, Adrian; Shaw, Chris; Raven, Rob; Verhees, Bram

    2014-01-01

    Offshore wind technology has recently undergone rapid deployment in the UK. And yet, up until recently, the UK was considered a laggard in terms of deploying renewable energy. How can this burst of offshore wind activity be explained? An economic analysis would seek signs for newfound competitiveness for offshore wind in energy markets. A policy analysis would highlight renewable energy policy developments and assess their contribution to economic prospects of offshore wind. However, neither perspective sheds sufficient light on the advocacy of the actors involved in the development and deployment of the technology. Without an account of technology politics it is hard to explain continuing policy support despite rising costs. By analysing the actor networks and narratives underpinning policy support for offshore wind, we explain how a fairly effective protective space was constructed through the enroling of key political and economic interests. - Highlights: • UK is world leader in offshore wind deployment. • Article explains boom in deployment by looking at the politics of renewable energy policy. • Offshore wind is supported by a variety of actors with aligned political and economic interests. • Analysis highlights the importance of a system builder

  4. Matlab for engineers explained

    CERN Document Server

    Gustafsson, Fredrik

    2003-01-01

    This book is written for students at bachelor and master programs and has four different purposes, which split the book into four parts: 1. To teach first or early year undergraduate engineering students basic knowledge in technical computations and programming using MATLAB. The first part starts from first principles and is therefore well suited both for readers with prior exposure to MATLAB but lacking a solid foundational knowledge of the capabilities of the system and readers not having any previous experience with MATLAB. The foundational knowledge gained from these interactive guided tours of the system will hopefully be sufficient for an effective utilization of MATLAB in the engineering profession, in education and in research. 2. To explain the foundations of more advanced use of MATLAB using the facilities added the last couple of years, such as extended data structures, object orientation and advanced graphics. 3. To give an introduction to the use of MATLAB in typical undergraduate courses in elec...

  5. Explaining labor wedge trends: An equilibrium search approach

    Directory of Open Access Journals (Sweden)

    Coralia A. Quintero Rojas

    2016-06-01

    Full Text Available In this paper, we present a search and matching model of the labor market and use this as a device to explain the long-run variation in the aggregate hours worked in several OECD countries over the period 1980-2013. The model distinguishes between hours worked per employee (intensive margin and the employment rate (extensive margin and includes a tax/benefit system. This allows us to assess the impact of the observed time-varying heterogeneity of taxes, unemployment benefits, and workers’ bargaining power on the two margins. Our method is based on an accounting procedure. Once it has been calibrated, we find that, for the ten countries of the sample, our search economy is able to explain the patterns of the two margins of aggregate hours worked over the 1980-2013 period, when it includes the cross-country heterogeneity of the labor market institutions.

  6. Defense styles explain psychiatric symptoms: an empirical study.

    Science.gov (United States)

    Holi, M M; Sammallahti, P R; Aalberg, V A

    1999-11-01

    To examine the relation between psychiatric symptoms and defense mechanisms, we administered two questionnaires, the Symptom Check-list 90 (SCL-90) and the Defense Style Questionnaire (DSQ) to 122 psychiatric out-patients and to a community sample of 337 subjects. Using regression analysis, we found that 51.8% of the variation in subject's Global Severity Index value could be explained by his defense style. Of the three defense styles, the immature style explained most of the variation in the symptoms. We found little overall evidence for specific connections between particular defenses and symptoms. Projection and dissociation were central in most of the symptom dimensions. We compared patients and controls with the same level of general symptom severity and found that patients used significantly more devaluation and splitting, and controls used significantly more altruism and idealization. Whether defenses predispose to certain symptomatology or are one of its aspects is discussed.

  7. Fundamental volatility and stock returns : does fundamental volatility explain stock returns?

    OpenAIRE

    Selboe, Guner K.; Virdee, Jaspal Singh

    2017-01-01

    In this thesis, we investigate whether the fundamental uncertainty can explain the crosssection of stock returns. To measure the fundamental uncertainty, we estimate rolling standard deviations and accounting betas of four different fundamentals: revenues, gross profit, earnings and cash flows. The standard deviation and the beta of revenues significantly explain returns in the Fama-Macbeth procedure, but only appears significant among smaller stocks in the portfolio formation ...

  8. EXPLAINING THE ASSOCIATION BETWEEN INCARCERATION AND DIVORCE*

    Science.gov (United States)

    Siennick, Sonja E.; Stewart, Eric A.; Staff, Jeremy

    2014-01-01

    Recent studies have suggested that incarceration dramatically increases the odds of divorce, but we know little about the mechanisms that explain the association. This study uses prospective longitudinal data from a subset of married young adults in the National Longitudinal Study of Adolescent Health (N = 1,919) to examine whether incarceration is associated with divorce indirectly via low marital love, economic strain, relationship violence, and extramarital sex. The findings confirmed that incarcerations occurring during, but not before, a marriage were associated with an increased hazard of divorce. Incarcerations occurring during marriage also were associated with less marital love, more relationship violence, more economic strain, and greater odds of extramarital sex. Above-average levels of economic strain were visible among respondents observed preincarceration, but only respondents observed postincarceration showed less marital love, more relationship violence, and higher odds of extramarital sex than did respondents who were not incarcerated during marriage. These relationship problems explained approximately 40 percent of the association between incarceration and marital dissolution. These findings are consistent with theoretical predictions that a spouse’s incarceration alters the rewards and costs of the marriage and the relative attractiveness of alternative partners. PMID:25598544

  9. Explaining the Origins and Expansion of Mass Education.

    Science.gov (United States)

    Boli, John; And Others

    1985-01-01

    Theories of mass education that emphasize processes of differentiation or the reproduction of inequalities ignore the universal and institutional character of mass education. A theoretical framework emphasizing individualism and the rationalization of individual and collective authority better explains the relationship of mass education to…

  10. Thermally-assisted Magma Emplacement Explains Restless Calderas

    Science.gov (United States)

    Amoruso, A.; Crescentini, L.; D'Antonio, M.; Acocella, V.

    2017-12-01

    Many calderas show repeated unrest over centuries. Though probably induced by magma, this unique behaviour is not understood and its dynamics remains elusive. To better understand these restless calderas, we interpret deformation data and build thermal models of Campi Flegrei, Italy, which is the best-known, yet most dangerous calderas, lying to the west of Naples and restless since the 1950s at least.Our elaboration of the geodetic data indicates that the inflation and deflation of magmatic sources at the same location explain most deformation, at least since the build-up of the last 1538 AD eruption. However, such a repeated magma emplacement requires a persistently hot crust.Our thermal models show that the repeated emplacement was assisted by the thermal anomaly created by magma that was intruded at shallow depth 3 ka before the last eruption and, in turn, contributed to maintain the thermal anomaly itself. This may explain the persistence of the magmatic sources promoting the restless behaviour of the Campi Flegrei caldera; moreover, it explains the crystallization, re-melting and mixing among compositionally distinct magmas recorded in young volcanic rocks.Available information at other calderas highlights similarities to Campi Flegrei, in the pattern and cause of unrest. All monitored restless calderas have either geodetically (Yellowstone, Aira Iwo-Jima, Askja, Fernandina and, partly, Long Valley) or geophysically (Rabaul, Okmok) detected sill-like intrusions inducing repeated unrest. Some calderas (Yellowstone, Long Valley) also show stable deformation pattern, where inflation insists on and mimics the resurgence uplift. The common existence of sill-like sources, also responsible for stable deformation patterns, in restless calderas suggests close similarities to Campi Flegrei. This suggests a wider applicability of our model of thermally-assisted sill emplacement, to be tested by future studies to better understand not only the dynamics of restless

  11. The Role of Secondary Education in Explaining Competitiveness

    Science.gov (United States)

    Baumann, Chris; Winzar, Hume

    2016-01-01

    The literature establishes that education drives economic performance, but the extent that education is associated with a country's competitiveness is empirically untested. Our study analyses Programme for International Student Assessment (PISA) data from 63 countries to ascertain education's role in explaining the competitiveness of a country.…

  12. The Effect of Self-Explaining on Robust Learning

    Science.gov (United States)

    Hausmann, Robert G. M.; VanLehn, Kurt

    2010-01-01

    Self-explaining is a domain-independent learning strategy that generally leads to a robust understanding of the domain material. However, there are two potential explanations for its effectiveness. First, self-explanation generates additional "content" that does not exist in the instructional materials. Second, when compared to…

  13. Juvenile Delinquency Explained? A Test of Containment Theory.

    Science.gov (United States)

    Thompson, William E.; Dodder, Richard A.

    1983-01-01

    Examines the extent to which variation in self-reported delinquency is explained by the seven containment variables (favorable self-concept, goal orientation, frustration tolerance, retention of norms, internalization of rules, availability of meaningful roles, and group reinforcement), and focuses on racial and sex differences in self-reported…

  14. Functional traits explain ecosystem function through opposing mechanisms.

    Science.gov (United States)

    Cadotte, Marc W

    2017-08-01

    The ability to explain why multispecies assemblages produce greater biomass compared to monocultures, has been a central goal in the quest to understand biodiversity effects on ecosystem function. Species contributions to ecosystem function can be driven by two processes: niche complementarity and a selection effect that is influenced by fitness (competitive) differences, and both can be approximated with measures of species' traits. It has been hypothesised that fitness differences are associated with few, singular traits while complementarity requires multidimensional trait measures. Here, using experimental data from plant assemblages, I show that the selection effect was strongest when trait dissimilarity was low, while complementarity was greatest with high trait dissimilarity. Selection effects were best explained by a single trait, plant height. Complementarity was correlated with dissimilarity across multiple traits, representing above and below ground processes. By identifying the relevant traits linked to ecosystem function, we obtain the ability to predict combinations of species that will maximise ecosystem function. © 2017 John Wiley & Sons Ltd/CNRS.

  15. Tuned Normalization Explains the Size of Attention Modulations

    Science.gov (United States)

    Ni, Amy M.; Ray, Supratim; Maunsell, John H. R.

    2012-01-01

    SUMMARY The effect of attention on firing rates varies considerably within a single cortical area. The firing rate of some neurons is greatly modulated by attention while others are hardly affected. The reason for this variability across neurons is unknown. We found that the variability in attention modulation across neurons in area MT of macaques can be well explained by variability in the strength of tuned normalization across neurons. The presence of tuned normalization also explains a striking asymmetry in attention effects within neurons: when two stimuli are in a neuron’s receptive field, directing attention to the preferred stimulus modulates firing rates more than directing attention to the non-preferred stimulus. These findings show that much of the neuron-to-neuron variability in modulation of responses by attention depends on variability in the way the neurons process multiple stimuli, rather than differences in the influence of top-down signals related to attention. PMID:22365552

  16. [Pay for performance explained by transaction costs theory].

    Science.gov (United States)

    Gorbaneff, Yuri; Cortes, Ariel; Torres, Sergio; Yepes, Francisco

    2011-01-01

    To evaluate the ability of transaction costs theory to explain incentives in the health care chain. We performed a case study of CPS, a health insurance company in Bogota (Colombia), which preferred not to publish its name. CPS moves in the environment of high transaction costs and uses the hybrid form of governance at the outpatient level. Incentive intensity, administrative control and the contract all agree with the theory. At the hospital level, the market is used, despite greater uncertainty. Because of the discrete form (1.0) of the incentives and the absence of administrative control, it is difficult for CPS to relate payment to hospital performance. Transaction costs theory explains the configuration of incentives. Another contribution made by this theory to the literature is the criterion to differentiate between the market and the hybrid. We propose that the market uses discrete-type (1.0) incentives, while the hybrid uses continuous, commission-like incentives. Copyright © 2011 SESPAS. Published by Elsevier Espana. All rights reserved.

  17. Tuned normalization explains the size of attention modulations.

    Science.gov (United States)

    Ni, Amy M; Ray, Supratim; Maunsell, John H R

    2012-02-23

    The effect of attention on firing rates varies considerably within a single cortical area. The firing rate of some neurons is greatly modulated by attention while others are hardly affected. The reason for this variability across neurons is unknown. We found that the variability in attention modulation across neurons in area MT of macaques can be well explained by variability in the strength of tuned normalization across neurons. The presence of tuned normalization also explains a striking asymmetry in attention effects within neurons: when two stimuli are in a neuron's receptive field, directing attention to the preferred stimulus modulates firing rates more than directing attention to the nonpreferred stimulus. These findings show that much of the neuron-to-neuron variability in modulation of responses by attention depends on variability in the way the neurons process multiple stimuli, rather than differences in the influence of top-down signals related to attention. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Development of Phaeocystis globosa blooms in the upwelling waters of the South Central coast of Viet Nam

    Science.gov (United States)

    Hai, Doan-Nhu; Lam, Nguyen-Ngoc; Dippner, Joachim W.

    2010-11-01

    Blooms of haptophyte algae in the south central coastal waters of Viet Nam often occur in association with upwelling phenomenon during the southwest (SW) monsoon. Depending on the magnitude of the blooms, damage to aquaculture farms may occur. Based on two years of data on biology, oceanography, and marine chemistry, the present study suggests a conceptual model of the growth of the haptophyte Phaeocystis globosa. At the beginning of the bloom, low temperature and abundant nutrient supply, especially nitrate from rain and upwelling, favour bloom development. Diatoms utilize available nitrate and phosphate; subsequently, higher ammonium concentration allows P. globosa to grow faster than the diatoms. At the end of the Phaeocystis bloom, free cells may become available as food for a heterotrophic dinoflagellate species, Noctiluca scintillans. During and after the phytoplankton bloom, remineralization by bacteria reduces dissolved oxygen to a very low concentration at depth, and favors growth of nitrate-reducing bacteria.A Lagrangian Harmful Algal Bloom (HAB) model, driven by a circulation model of the area, realistically simulates the transport of microalgae in surface waters during strong and weak SW monsoon periods, suggesting that it may be a good tool for early warning of HABs in Vietnamese coastal waters.

  19. Content-Free Computer Supports for Self-Explaining: Modifiable Typing Interface and Prompting

    Science.gov (United States)

    Chou, Chih-Yueh; Liang, Hung-Ta

    2009-01-01

    Self-explaining, which asks students to generate explanations while reading a text, is a self-constructive activity and is helpful for students' learning. Studies have revealed that prompts by a human tutor promote students' self-explanations. However, most studies on self-explaining focus on spoken self-explanations. This study investigates the…

  20. On the explaining-away phenomenon in multivariate latent variable models.

    Science.gov (United States)

    van Rijn, Peter; Rijmen, Frank

    2015-02-01

    Many probabilistic models for psychological and educational measurements contain latent variables. Well-known examples are factor analysis, item response theory, and latent class model families. We discuss what is referred to as the 'explaining-away' phenomenon in the context of such latent variable models. This phenomenon can occur when multiple latent variables are related to the same observed variable, and can elicit seemingly counterintuitive conditional dependencies between latent variables given observed variables. We illustrate the implications of explaining away for a number of well-known latent variable models by using both theoretical and real data examples. © 2014 The British Psychological Society.

  1. Explaining formation of Astronomical Jets using Dynamic Universe Model

    Science.gov (United States)

    Naga Parameswara Gupta, Satyavarapu

    2016-07-01

    Astronomical jets are observed from the centres of many Galaxies including our own Milkyway. The formation of such jet is explained using SITA simulations of Dynamic Universe Model. For this purpose the path traced by a test neutron is calculated and depicted using a set up of one densemass of the mass equivalent to mass of Galaxy center, 90 stars with similar masses of stars near Galaxy center, mass equivalents of 23 Globular Cluster groups, 16 Milkyway parts, Andromeda and Triangulum Galaxies at appropriate distances. Five different kinds of theoretical simulations gave positive results The path travelled by this test neutron was found to be an astronomical jet emerging from Galaxy center. This is another result from Dynamic Universe Model. It solves new problems like a. Variable Mass Rocket Trajectory Problem b. Explaining Very long baseline interferometry (VLBI) observations c. Astronomical jets observed from Milkyway Center d. Prediction of Blue shifted Galaxies e. Explaining Pioneer Anomaly f. Prediction of New Horizons satellite trajectory etc. Dynamic Universe Model never reduces to General relativity on any condition. It uses a different type of mathematics based on Newtonian physics. This mathematics used here is simple and straightforward. As there are no differential equations present in Dynamic Universe Model, the set of equations give single solution in x y z Cartesian coordinates for every point mass for every time step

  2. Use of environmental parameters to explain the variability in ...

    African Journals Online (AJOL)

    Abstract. This study attempts to explain the variability in recruitment of sardine in the northern Benguela and to develop potential models by including environmental information to predict recruitment. ... AJOL African Journals Online. HOW TO ...

  3. Persistent villi hypoperfusion explains intramucosal acidosis in sheep endotoxemia

    NARCIS (Netherlands)

    Dubin, Arnaldo; Edul, Vanina Siham Kanoore; Pozo, Mario Omar; Murias, Gastón; Canullán, Carlos Manuel; Martins, Enrique Francisco; Ferrara, Gonzalo; Canales, Héctor Saul; Laporte, Mercedes; Estenssoro, Elisa; Ince, Can

    2008-01-01

    OBJECTIVE: To test the hypothesis that persistent villi hypoperfusion explains intramucosal acidosis after endotoxemic shock resuscitation. DESIGN: Controlled experimental study. SETTING: University-based research laboratory. SUBJECTS: A total of 14 anesthetized, mechanically ventilated sheep.

  4. Plate-wide stress relaxation explains European Palaeocene basin inversions

    DEFF Research Database (Denmark)

    Nielsen, S.B.; Thomsen, Erik; Hansen, D.L.

    2005-01-01

    of the in-plane tectonic stress. The onset of relaxation inversions was plate-wide and simultaneous, and may have been triggered by stress changes caused by elevation of the North Atlantic lithosphere by the Iceland plume or the drop in NS convergence rate between Africa and Europe.......During Late Cretaceous and Cenozoic times many Paleozoic and Mesozoic rifts and basin structures in the interior of the European continent underwent several phases of inversion. The main phases occurred during the Late Cretaceous and Middle Paleocene, and have been explained by pulses...... Paleocene phase was characterized by domal uplift of a wider area with only mild fault movements, and formation of more distal and shallow marginal troughs. A simple flexural model explains how domal, secondary inversion follows inevitably from primary, convergence related inversion upon relaxation...

  5. Explaining the harmonic sequence paradox.

    Science.gov (United States)

    Schmidt, Ulrich; Zimper, Alexander

    2012-05-01

    According to the harmonic sequence paradox, an expected utility decision maker's willingness to pay for a gamble whose expected payoffs evolve according to the harmonic series is finite if and only if his marginal utility of additional income becomes zero for rather low payoff levels. Since the assumption of zero marginal utility is implausible for finite payoff levels, expected utility theory - as well as its standard generalizations such as cumulative prospect theory - are apparently unable to explain a finite willingness to pay. This paper presents first an experimental study of the harmonic sequence paradox. Additionally, it demonstrates that the theoretical argument of the harmonic sequence paradox only applies to time-patient decision makers, whereas the paradox is easily avoided if time-impatience is introduced. ©2011 The British Psychological Society.

  6. Deep supervised, but not unsupervised, models may explain IT cortical representation.

    Directory of Open Access Journals (Sweden)

    Seyed-Mahdi Khaligh-Razavi

    2014-11-01

    Full Text Available Inferior temporal (IT cortex in human and nonhuman primates serves visual object recognition. Computational object-vision models, although continually improving, do not yet reach human performance. It is unclear to what extent the internal representations of computational models can explain the IT representation. Here we investigate a wide range of computational model representations (37 in total, testing their categorization performance and their ability to account for the IT representational geometry. The models include well-known neuroscientific object-recognition models (e.g. HMAX, VisNet along with several models from computer vision (e.g. SIFT, GIST, self-similarity features, and a deep convolutional neural network. We compared the representational dissimilarity matrices (RDMs of the model representations with the RDMs obtained from human IT (measured with fMRI and monkey IT (measured with cell recording for the same set of stimuli (not used in training the models. Better performing models were more similar to IT in that they showed greater clustering of representational patterns by category. In addition, better performing models also more strongly resembled IT in terms of their within-category representational dissimilarities. Representational geometries were significantly correlated between IT and many of the models. However, the categorical clustering observed in IT was largely unexplained by the unsupervised models. The deep convolutional network, which was trained by supervision with over a million category-labeled images, reached the highest categorization performance and also best explained IT, although it did not fully explain the IT data. Combining the features of this model with appropriate weights and adding linear combinations that maximize the margin between animate and inanimate objects and between faces and other objects yielded a representation that fully explained our IT data. Overall, our results suggest that explaining

  7. Explainers' development of science-learner identities through participation in a community of practice

    Science.gov (United States)

    Richardson, Anne E.

    The urgent environmental issues of today require science-literate adults to engage in business and political decisions to create solutions. Despite the need, few adults have the knowledge and skills of science literacy. This doctoral dissertation is an analytical case study examining the science-learner identity development of Exploratorium Field Trip Explainers. Located in San Francisco, CA, the Exploratorium is a museum of science, art, and human perception dedicated to nurturing curiosity and exploration. Data collected included semi-structured interviews with sixteen former Field Trip Explainers, participant observation of the current Field Trip Explainer Program, and review of relevant documentation. Data analysis employed constant comparative analysis, guided by the communities of practice theoretical framework (Wenger, 1998) and the National Research Council's (2009) Six Strands of Science Learning. Findings of this research indicate that Exploratorium Field Trip Explainers participate in a community of practice made up of a diverse group of people that values curiosity and openness to multiple ways of learning. Many participants entered the Field Trip Explainer Program with an understanding of science learning as a rigid process reserved for a select group of people; through participation in the Field Trip Explainer community of practice, participants developed an understanding of science learning as accessible and a part of everyday life. The findings of this case study have implications for research, theory, and practice in informal adult science learning, access of non-dominant groups to science learning, and adult workplace learning in communities of practice.

  8. "Explaining the Gender Wage Gap in Georgia"

    OpenAIRE

    Tamar Khitarishvili

    2009-01-01

    This paper evaluates gender wage differentials in Georgia between 2000 and 2004. Using ordinary least squares, we find that the gender wage gap in Georgia is substantially higher than in other transition countries. Correcting for sample selection bias using the Heckman approach further increases the gender wage gap. The Blinder Oaxaca decomposition results suggest that most of the wage gap remains unexplained. The explained portion of the gap is almost entirely attributed to industrial variab...

  9. Review of yield gap explaining factors and opportunities for alternative data collection approaches

    NARCIS (Netherlands)

    Beza, E.A.; Vasco Silva, João; Kooistra, Lammert; Reidsma, Pytrik

    2017-01-01

    Yield gap analysis is gaining increased scientific attention, as estimating and explaining yield gaps shows the potential for sustainable intensification of agricultural systems. Explaining yield gaps requires detailed information about the biophysical environment, crop management as well as

  10. Pre-service primary school teachers’ abilities in explaining water and air pollution scientifically

    Science.gov (United States)

    Lukmannudin; Sopandi, W.; Sujana, A.; Sukardi, R.

    2018-05-01

    The purpose of this study is to determine the ability of pre-service primary school teachers (PSPST) in explaining the phenomenon of water and air pollution scientifically. The research method used descriptive method of analysis with qualitative approach. The respondents were PSPTP at 4th semester. This study used a four-tier instrument diagnostic test. The number of subjects was 84 PSPTP at Universitas Pendidikan Indonesia, Kampus Daerah Sumedang. The results demonstrate the ability of PSPST in explaining water and air pollution scientifically. The results show that only 6% of PSPST who are able to explain the phenomenon of water pollution and only 4% of PSPST who are able to explain the phenomenon of air pollution. The fact should be attention for PSPST because these understanding are crucial in the process of learning activities in the classroom.

  11. Light-Dependent Transcriptional Regulation of Genes of Biogeochemical Interest in the Diploid and Haploid Life Cycle Stages of Emiliania huxleyi▿ †

    Science.gov (United States)

    Richier, Sophie; Kerros, Marie-Emmanuelle; de Vargas, Colomban; Haramaty, Liti; Falkowski, Paul G.; Gattuso, Jean-Pierre

    2009-01-01

    The expression of genes of biogeochemical interest in calcifying and noncalcifying life stages of the coccolithophore Emiliania huxleyi was investigated. Transcripts potentially involved in calcification were tested through a light-dark cycle. These transcripts were more abundant in calcifying cells and were upregulated in the light. Their application as potential candidates for in situ biogeochemical proxies is also suggested. PMID:19304825

  12. Why Compositional Convection Cannot Explain Substellar Objects’ Sharp Spectral-type Transitions

    Science.gov (United States)

    Leconte, Jérémy

    2018-02-01

    As brown dwarfs and young giant planets cool down, they are known to experience various chemical transitions—for example, from {CO} rich L-dwarfs to methane rich T-dwarfs. Those chemical transitions are accompanied by spectral transitions with sharpness that cannot be explained by chemistry alone. In a series of articles, Tremblin et al. proposed that some of the yet-unexplained features associated with these transitions could be explained by a reduction of the thermal gradient near the photosphere. To explain, in turn, this more isothermal profile, they invoke the presence of an instability analogous to fingering convection—compositional convection—triggered by the change in mean molecular weight of the gas due to the chemical transitions mentioned above. In this Letter, we use existing arguments to demonstrate that any turbulent transport, if present, would in fact increase the thermal gradient. This misinterpretation comes from the fact that turbulence mixes/homogenizes entropy (potential temperature) instead of temperature. So, while increasing transport, turbulence in an initially stratified atmosphere actually carries energy downward, whether it is due to fingering or any other type of compositional convection. These processes therefore cannot explain the features observed along the aforementioned transitions by reducing the thermal gradient in the atmosphere of substellar objects. Understanding the microphysical and dynamical properties of clouds at these transitions thus probably remains our best way forward.

  13. EXPLAINING THE MOTHERHOOD WAGE PENALTY DURING THE EARLY OCCUPATIONAL CAREER

    Science.gov (United States)

    STAFF, JEREMY; MORTIMER, JEYLAN T.

    2011-01-01

    Prior research shows that mothers earn lower hourly wages than women without children, and that this maternal wage penalty cannot be fully explained by differences between mothers and other women in work experience and job characteristics. This research examines whether the residual motherhood wage penalty results from differences between mothers and other women in the accumulation of work interruptions and breaks in schooling. Using longitudinal data for 486 women followed from ages 19 to 31 in the Youth Development Study, we find that accumulated months not in the labor force and not enrolled in school explain the residual pay gap between mothers and other women. PMID:22037996

  14. Explaining Tevatron leptons photons missing- T events with ...

    Indian Academy of Sciences (India)

    Abstract. The CDF experiment reported a lepton photon missing transverse energy. (/ET) signal 3σ in excess of the standard model prediction in Tevatron Run I data. The excess can be explained by the resonant production of a smuon, which subsequently decays to a muon, a photon and a gravitino. Here, we perform ...

  15. A More Practical Method for Explaining Equilibrium

    OpenAIRE

    Yi-Jang Yu

    2014-01-01

    The aim of this study is to suggest a more practical method for explaining market equilibrium in a two-dimensional risk-return world. Its main difference from textbook contents is to define, in both qualitative and quantitative ways, the environment or the system factor and treat it as an endogenous variable. Once the two-dimensional framework that is capable of managing uncertainty and environmental relationship can be reasonably established, a greater number of economic issues can be effect...

  16. Explaining seeing? Disentangling qualia from perceptual organization.

    Science.gov (United States)

    Ibáñez, Agustin; Bekinschtein, Tristan

    2010-09-01

    Abstract Visual perception and integration seem to play an essential role in our conscious phenomenology. Relatively local neural processing of reentrant nature may explain several visual integration processes (feature binding or figure-ground segregation, object recognition, inference, competition), even without attention or cognitive control. Based on the above statements, should the neural signatures of visual integration (via reentrant process) be non-reportable phenomenological qualia? We argue that qualia are not required to understand this perceptual organization.

  17. How Much of Language Acquisition Does Operant Conditioning Explain?

    Science.gov (United States)

    Sturdy, Christopher B; Nicoladis, Elena

    2017-01-01

    Since the 1950s, when Chomsky argued that Skinner's arguments could not explain syntactic acquisition, psychologists have generally avoided explicitly invoking operant or instrumental conditioning as a learning mechanism for language among human children. In this article, we argue that this is a mistake. We focus on research that has been done on language learning in human infants and toddlers in order to illustrate our points. Researchers have ended up inventing learning mechanisms that, in actual practice, not only resemble but also in fact are examples of operant conditioning (OC) by any other name they select. We argue that language acquisition researchers should proceed by first ruling out OC before invoking alternative learning mechanisms. While it is possible that OC cannot explain all of the language acquisition, simple learning mechanisms that work across species may have some explanatory power in children's language learning.

  18. Asset pricing puzzles explained by incomplete Brownian equilibria

    DEFF Research Database (Denmark)

    Christensen, Peter Ove; Larsen, Kasper

    We examine a class of Brownian based models which produce tractable incomplete equilibria. The models are based on finitely many investors with heterogeneous exponential utilities over intermediate consumption who receive partially unspanned income. The investors can trade continuously on a finit...... markets. Consequently, our model can simultaneously help explaining the risk-free rate and equity premium puzzles....

  19. Weaker dental enamel explains dental decay.

    Science.gov (United States)

    Vieira, Alexandre R; Gibson, Carolyn W; Deeley, Kathleen; Xue, Hui; Li, Yong

    2015-01-01

    Dental caries continues to be the most prevalent bacteria-mediated non-contagious disease of humankind. Dental professionals assert the disease can be explained by poor oral hygiene and a diet rich in sugars but this does not account for caries free individuals exposed to the same risk factors. In order to test the hypothesis that amount of amelogenin during enamel development can influence caries susceptibility, we generated multiple strains of mice with varying levels of available amelogenin during dental development. Mechanical tests showed that dental enamel developed with less amelogenin is "weaker" while the dental enamel of animals over-expressing amelogenin appears to be more resistant to acid dissolution.

  20. SOME THEORETICAL MODELS EXPLAINING ADVERTISING EFFECTS

    Directory of Open Access Journals (Sweden)

    Vasilica Magdalena SOMEŞFĂLEAN

    2014-06-01

    Full Text Available Persuade clients is still the main focus of the companies, using a set of methods and techniques designed to influence their behavior, in order to obtain better results (profits over a longer period of time. Since the late nineteenth - early twentieth century, the american E.St.Elmo Lewis, considered a pioneer in advertising and sales, developed the first theory, AIDA model, later used by marketers and advertisers to develop a marketing communications strategy. Later studies have developed other models that are the main subject of this research, which explains how and why persuasive communication works, to understand why some approaches are effective and others are not.

  1. Explaining socio-demographic differences in disengagement from sports in adolescence.

    Science.gov (United States)

    Prins, Richard G; Kamphuis, Carlijn B M; van Empelen, Pepijn; Beenackers, Mariëlle A; Brug, Johannes; Mackenbach, Johan P; Oenema, Anke

    2013-10-01

    The purpose of this longitudinal study is to identify risk groups for disengagement from sports during adolescence. In addition, it will be explored whether cognitive and environmental factors can explain socio-demographic differences in disengagement from sports. Data were obtained from the Environmental Determinants of Obesity in Rotterdam Schoolchildren study, and 357 adolescents were eligible for analysis. Socio-demographics (gender, ethnicity, education), individual cognitions and neighbourhood perceptions were assessed at baseline (2005/2006), and sports participation at baseline and at follow-up (2007/2008). Two dichotomous outcome variables were constructed: (i) disengagement from sports (yes/no) and (ii) ceased compliance with the fitnorm (i.e. cease engaging in sports ≥3 times/wk) (yes/no). In logistic regression and mediation analyses, we identified socio-demographic differences in the two outcomes. Subsequently, we applied mediation analyses to identify the contribution of cognitive and environmental explanatory factors of the socio-demographic differences. Girls [odds ratio (OR): 2.5, 95% confidence interval (CI): 1.5-4.5] were more likely than boys to disengage from sports. Girls (OR: 2.5, 95% CI: 1.4-4.2), adolescents of non-Western background (OR: 1.8, 95% CI: 1.0-3.0) and those in lower educational levels (OR: 1.7, 95% CI: 1.0-2.9) were more likely to cease compliance with the fitnorm. Perceived neighbourhood safety partly explained gender differences in disengagement from sports (8%). Intention partly explained ethnical (32%) and educational differences (37%) in ceasing compliance with the fitnorm. Girls, lower-educated adolescents and those with a non-Western background showed more pronounced reductions in sports participation and compliance with the fitnorm. Intention and perceived neighbourhood safety could partially explain these differences.

  2. Explaining mastitis incidence in Dutch dairy farming: the influence of farmers' attitudes and behaviour.

    Science.gov (United States)

    Jansen, J; van den Borne, B H P; Renes, R J; van Schaik, G; Lam, T J G M; Leeuwis, C

    2009-11-15

    When mastitis incidence increases, either infection pressure has increased or cows' resistance has decreased. This usually indicates that farm management is not optimal. Numerous quantitative studies have demonstrated the effect of management practices on mastitis. In most of these studies, the identified risk factors could explain only part of the variance in mastitis incidence on farms. Several studies suggest that the unexplained variance is caused by farmers' attitudes towards different aspects of mastitis treatment and preventive behaviour. This study aims to determine, to quantify and to specify the extent to which farmers' attitudes, over and above farmers' behaviour, are factors that explain the variation in mastitis incidence, measured in terms of the quantifiable effect of management factors. An extensive survey on self-reported attitudes, behaviour and mastitis incidence was conducted on 336 Dutch dairy farms. Results of multiple linear regression analyses show that farmers' self-reported behaviour and attitudes together explain 48%, 31% and 23% of the variation within, respectively, the average farm bulk milk somatic cell count (BMSCC), the clinical mastitis incidence and the combined clinical and subclinical mastitis incidence. Both behaviour and attitudes explain part of the variance. However, most of the variance in all three dependant measures is explained solely by the attitude variables. The variation in BMSCC value is best explained by (1) farmers' normative frame of reference about mastitis, (2) farmers' perceptions about the control of mastitis and (3) the perceived effect of a BMSCC penalty level. The variation in clinical mastitis is best explained by farmers' perceptions about mastitis control. The variation in the combined clinical and subclinical mastitis incidence rate is best explained by the perceived effect of a BMSCC penalty level and the frequency of contact with others. The results of this study show that farmers' attitudes are a

  3. Plastid genomes of two brown algae, Ectocarpus siliculosus and Fucus vesiculosus: further insights on the evolution of red-algal derived plastids

    Directory of Open Access Journals (Sweden)

    Corre Erwan

    2009-10-01

    Full Text Available Abstract Background Heterokont algae, together with cryptophytes, haptophytes and some alveolates, possess red-algal derived plastids. The chromalveolate hypothesis proposes that the red-algal derived plastids of all four groups have a monophyletic origin resulting from a single secondary endosymbiotic event. However, due to incongruence between nuclear and plastid phylogenies, this controversial hypothesis remains under debate. Large-scale genomic analyses have shown to be a powerful tool for phylogenetic reconstruction but insufficient sequence data have been available for red-algal derived plastid genomes. Results The chloroplast genomes of two brown algae, Ectocarpus siliculosus and Fucus vesiculosus, have been fully sequenced. These species represent two distinct orders of the Phaeophyceae, which is a major group within the heterokont lineage. The sizes of the circular plastid genomes are 139,954 and 124,986 base pairs, respectively, the size difference being due principally to the presence of longer inverted repeat and intergenic regions in E. siliculosus. Gene contents of the two plastids are similar with 139-148 protein-coding genes, 28-31 tRNA genes, and 3 ribosomal RNA genes. The two genomes also exhibit very similar rearrangements compared to other sequenced plastid genomes. The tRNA-Leu gene of E. siliculosus lacks an intron, in contrast to the F. vesiculosus and other heterokont plastid homologues, suggesting its recent loss in the Ectocarpales. Most of the brown algal plastid genes are shared with other red-algal derived plastid genomes, but a few are absent from raphidophyte or diatom plastid genomes. One of these regions is most similar to an apicomplexan nuclear sequence. The phylogenetic relationship between heterokonts, cryptophytes and haptophytes (collectively referred to as chromists plastids was investigated using several datasets of concatenated proteins from two cyanobacterial genomes and 18 plastid genomes, including

  4. Distribution of lipid biomarkers and carbon isotope fractionation in contrasting trophic environments of the South East Pacific

    Directory of Open Access Journals (Sweden)

    I. Tolosa

    2008-06-01

    Full Text Available The distribution of lipid biomarkers and their stable carbon isotope composition was investigated on suspended particles from different contrasting trophic environments at six sites in the South East Pacific. High algal biomass with diatom-related lipids (24-methylcholesta-5,24(28-dien-3β-ol, C25 HBI alkenes, C16:4 FA, C20:5 FA was characteristic in the upwelling zone, whereas haptophyte lipids (long-chain (C37-C39 unsaturated ketones were proportionally most abundant in the nutrient-poor settings of the centre of the South Pacific Gyre and on its easter edge. The dinoflagellate–sterol, 4α-23,24-trimethylcholest-22(E-en-3β-ol, was a minor contributor in all of the studied area and the cyanobacteria-hydrocarbon, C17n-alkane, was at maximum in the high nutrient low chlorophyll regime of the subequatorial waters near the Marquesas archipelago.

    The taxonomic and spatial variability of the relationships between carbon photosynthetic fractionation and environmental conditions for four specific algal taxa (diatoms, haptophytes, dinoflagellates and cyanobacteria was also investigated. The carbon isotope fractionation factor (εp of the 24-methylcholesta-5,24(28-dien-3β-ol diatom marker, varied over a range of 16% along the different trophic systems. In contrast, εp of dinoflagellate, cyanobacteria and alkenone markers varied only by 7–10‰. The low fractionation factors and small variations between the different phytoplankton markers measured in the upwelling area likely reveals uniformly high specific growth rates within the four phytoplankton taxa, and/or that transport of inorganic carbon into phytoplankton cells may not only occur by diffusion but also by other carbon concentrating mechanisms (CCM. In contrast, in the oligotrophic zone, i.e. gyre and eastgyre, relatively high εp values, especially for the diatom marker

  5. Explaining the Pattern of CSDP-Operations: Towards a Theoretical Synthesis

    Directory of Open Access Journals (Sweden)

    Tim Haesebrouck

    2015-06-01

    Full Text Available The EU’s Common Security and Defence Policy (CSDP has mainly been used to deploy small-scale operations, which generally did not provide the member states with clear security benefits. This article combines insights from different theories of international relations to explain this disappointing track record. It argues that liberal theories adequately identify the domestic pressures the member states’ governments need to accommodate in the area of crisis management. Constructivism, on its part, properly emphasises the diverging strategic cultures of the member states. Both theories however fail to explain why domestic pressures and diverging strategic cultures lead to small-scale operations. Rational-choice institutionalism does provide a convincing explanation for the latter by drawing attention to the CSDP’s ineffective institutional design. Realism, in turn, is best positioned to explain why the CSDP was not designed more effectively, by emphasising the reluctance of states to transfer sovereignty to international organisations. The article concludes by discussing two measures that could alleviate the impact of the identified impediments on the CSDP’s track record: devising a CSDP-strategy and adapting the consensus rule. However, since the latter is very unlikely in the near future, the CSDP is not expected to develop into a more effective framework for crisis management.

  6. Explaining ecological clusters of maternal depression in South Western Sydney

    Science.gov (United States)

    2014-01-01

    Background The aim of the qualitative study reported here was to: 1) explain the observed clustering of postnatal depressive symptoms in South Western Sydney; and 2) identify group-level mechanisms that would add to our understanding of the social determinants of maternal depression. Methods Critical realism provided the methodological underpinning for the study. The setting was four local government areas in South Western Sydney, Australia. Child and Family practitioners and mothers in naturally occurring mothers groups were interviewed. Results Using an open coding approach to maximise emergence of patterns and relationships we have identified seven theoretical concepts that might explain the observed spatial clustering of maternal depression. The theoretical concepts identified were: Community-level social networks; Social Capital and Social Cohesion; "Depressed community"; Access to services at the group level; Ethnic segregation and diversity; Supportive social policy; and Big business. Conclusions We postulate that these regional structural, economic, social and cultural mechanisms partially explain the pattern of maternal depression observed in families and communities within South Western Sydney. We further observe that powerful global economic and political forces are having an impact on the local situation. The challenge for policy and practice is to support mothers and their families within this adverse regional and global-economic context. PMID:24460690

  7. Genetic pleiotropy explains associations between musical auditory discrimination and intelligence.

    Science.gov (United States)

    Mosing, Miriam A; Pedersen, Nancy L; Madison, Guy; Ullén, Fredrik

    2014-01-01

    Musical aptitude is commonly measured using tasks that involve discrimination of different types of musical auditory stimuli. Performance on such different discrimination tasks correlates positively with each other and with intelligence. However, no study to date has explored these associations using a genetically informative sample to estimate underlying genetic and environmental influences. In the present study, a large sample of Swedish twins (N = 10,500) was used to investigate the genetic architecture of the associations between intelligence and performance on three musical auditory discrimination tasks (rhythm, melody and pitch). Phenotypic correlations between the tasks ranged between 0.23 and 0.42 (Pearson r values). Genetic modelling showed that the covariation between the variables could be explained by shared genetic influences. Neither shared, nor non-shared environment had a significant effect on the associations. Good fit was obtained with a two-factor model where one underlying shared genetic factor explained all the covariation between the musical discrimination tasks and IQ, and a second genetic factor explained variance exclusively shared among the discrimination tasks. The results suggest that positive correlations among musical aptitudes result from both genes with broad effects on cognition, and genes with potentially more specific influences on auditory functions.

  8. What Explains Patterns of Diversification and Richness among Animal Phyla?

    Science.gov (United States)

    Jezkova, Tereza; Wiens, John J

    2017-03-01

    Animal phyla vary dramatically in species richness (from one species to >1.2 million), but the causes of this variation remain largely unknown. Animals have also evolved striking variation in morphology and ecology, including sessile marine taxa lacking heads, eyes, limbs, and complex organs (e.g., sponges), parasitic worms (e.g., nematodes, platyhelminths), and taxa with eyes, skeletons, limbs, and complex organs that dominate terrestrial ecosystems (arthropods, chordates). Relating this remarkable variation in traits to the diversification and richness of animal phyla is a fundamental yet unresolved problem in biology. Here, we test the impacts of 18 traits (including morphology, ecology, reproduction, and development) on diversification and richness of extant animal phyla. Using phylogenetic multiple regression, the best-fitting model includes five traits that explain ∼74% of the variation in diversification rates (dioecy, parasitism, eyes/photoreceptors, a skeleton, nonmarine habitat). However, a model including just three (skeleton, parasitism, habitat) explains nearly as much variation (∼67%). Diversification rates then largely explain richness patterns. Our results also identify many striking traits that have surprisingly little impact on diversification (e.g., head, limbs, and complex circulatory and digestive systems). Overall, our results reveal the key factors that shape large-scale patterns of diversification and richness across >80% of all extant, described species.

  9. Explaining ecological clusters of maternal depression in South Western Sydney.

    Science.gov (United States)

    Eastwood ED, John; Kemp, Lynn; Jalaludin, Bin

    2014-01-24

    The aim of the qualitative study reported here was to: 1) explain the observed clustering of postnatal depressive symptoms in South Western Sydney; and 2) identify group-level mechanisms that would add to our understanding of the social determinants of maternal depression. Critical realism provided the methodological underpinning for the study. The setting was four local government areas in South Western Sydney, Australia. Child and Family practitioners and mothers in naturally occurring mothers groups were interviewed. Using an open coding approach to maximise emergence of patterns and relationships we have identified seven theoretical concepts that might explain the observed spatial clustering of maternal depression. The theoretical concepts identified were: Community-level social networks; Social Capital and Social Cohesion; "Depressed community"; Access to services at the group level; Ethnic segregation and diversity; Supportive social policy; and Big business. We postulate that these regional structural, economic, social and cultural mechanisms partially explain the pattern of maternal depression observed in families and communities within South Western Sydney. We further observe that powerful global economic and political forces are having an impact on the local situation. The challenge for policy and practice is to support mothers and their families within this adverse regional and global-economic context.

  10. Psychological flexibility and mindfulness explain intuitive eating in overweight adults.

    Science.gov (United States)

    Sairanen, Essi; Tolvanen, Asko; Karhunen, Leila; Kolehmainen, Marjukka; Järvelä, Elina; Rantala, Sanni; Peuhkuri, Katri; Korpela, Riitta; Lappalainen, Raimo

    2015-07-01

    The current study investigated whether mindfulness and psychological flexibility, independently and together, explain intuitive eating. The participants were overweight or obese persons (N = 306) reporting symptoms of perceived stress and enrolled in a psychological lifestyle intervention study. Participants completed self-report measures of psychological flexibility; mindfulness including the subscales observe, describe, act with awareness, non-react, and non-judgment; and intuitive eating including the subscales unconditional permission to eat, eating for physical reasons, and reliance on hunger/satiety cues. Psychological flexibility and mindfulness were positively associated with intuitive eating factors. The results suggest that mindfulness and psychological flexibility are related constructs that not only account for some of the same variance in intuitive eating, but they also account for significant unique variances in intuitive eating. The present results indicate that non-judgment can explain the relationship between general psychological flexibility and unconditional permission to eat as well as eating for physical reasons. However, mindfulness skills-acting with awareness, observing, and non-reacting-explained reliance on hunger/satiety cues independently from general psychological flexibility. These findings suggest that mindfulness and psychological flexibility are interrelated but not redundant constructs and that both may be important for understanding regulation processes underlying eating behavior. © The Author(s) 2015.

  11. Do plant traits explain tree seedling survival in bogs?

    NARCIS (Netherlands)

    Limpens, J.; Egmond, van E.; Li, B.; Holmgren, M.

    2013-01-01

    Moss-dominated peat bogs store approximately 30% of global soil carbon. A climate induced shift from current moss-dominated conditions to tree-dominated states is expected to strongly affect their functioning and carbon sequestration capacity. Consequently, unraveling the mechanisms that may explain

  12. Do occupational demands explain the educational gradient in health?

    NARCIS (Netherlands)

    Meyer, S.C.; Künn-Nelen, A.C.

    2014-01-01

    The aim of this paper is to investigate to what extent occupation-specific demands explain the relationship between education and health. We concentrate on ergonomic, environmental, psychical, social and time demands. Merging the German Microcensus 2009 data with a dataset including detailed

  13. How Much of Language Acquisition Does Operant Conditioning Explain?

    Science.gov (United States)

    Sturdy, Christopher B.; Nicoladis, Elena

    2017-01-01

    Since the 1950s, when Chomsky argued that Skinner’s arguments could not explain syntactic acquisition, psychologists have generally avoided explicitly invoking operant or instrumental conditioning as a learning mechanism for language among human children. In this article, we argue that this is a mistake. We focus on research that has been done on language learning in human infants and toddlers in order to illustrate our points. Researchers have ended up inventing learning mechanisms that, in actual practice, not only resemble but also in fact are examples of operant conditioning (OC) by any other name they select. We argue that language acquisition researchers should proceed by first ruling out OC before invoking alternative learning mechanisms. While it is possible that OC cannot explain all of the language acquisition, simple learning mechanisms that work across species may have some explanatory power in children’s language learning. PMID:29163295

  14. How Much of Language Acquisition Does Operant Conditioning Explain?

    Directory of Open Access Journals (Sweden)

    Christopher B. Sturdy

    2017-10-01

    Full Text Available Since the 1950s, when Chomsky argued that Skinner’s arguments could not explain syntactic acquisition, psychologists have generally avoided explicitly invoking operant or instrumental conditioning as a learning mechanism for language among human children. In this article, we argue that this is a mistake. We focus on research that has been done on language learning in human infants and toddlers in order to illustrate our points. Researchers have ended up inventing learning mechanisms that, in actual practice, not only resemble but also in fact are examples of operant conditioning (OC by any other name they select. We argue that language acquisition researchers should proceed by first ruling out OC before invoking alternative learning mechanisms. While it is possible that OC cannot explain all of the language acquisition, simple learning mechanisms that work across species may have some explanatory power in children’s language learning.

  15. Main features of narrow sociological theories explaining mental disorders

    Directory of Open Access Journals (Sweden)

    Opalić Petar

    2006-01-01

    Full Text Available In the introduction, the author states that sociological theories explaining mental disorders in the narrow sense have originated as an opposition to medical, i.e. biological model of interpreting mental disorders. With regard to this, the following sociological theories explaining mental disorders are presented in more detail: theory of anomie by Durkheim and Merton (with Merton’s typology of deviant behavior, social roles theory by Parsons, labeling theory by Scheff and other authors, theoretical career model of the mentally ill, the concept of psychic disorder of etnomethodology and finally, the anti-psychiatric interpretation of mental disorders. It is concluded that, although historically older, sociological theories of the onset of mental disorders are filling the epistemological void that occurred in understanding the role of society on the whole and a series of social factors particularly on the different aspects of understanding mental disorders.

  16. Explaining residential moving intentions : the case of highway locations

    NARCIS (Netherlands)

    Hamersma, Marije; Heinen, Eva; Tillema, Taede; Arts, Jos

    2013-01-01

    In this paper Structural Equation Modeling is used to test a theoretical framework to explain the impact of highway externalities (i.e. accessibility and nuisance) on moving intentions of people living close to highways. We aimed to study whether highway externalities (alongside other contextual

  17. Does Interest rate Exposure explain the Low-Volatility Anomaly?

    NARCIS (Netherlands)

    Driessen, Joost; Kuiper, Ivo; Beilo, R.

    We show that part of the outperformance of low-volatility stocks can be explained by a premium for interest rate exposure. Low-volatility stock portfolios have negative exposure to interest rates, whereas the more volatile stocks have positive exposure. Incorporating an interest rate premium

  18. Does geography or ecology best explain 'cultural' variation among chimpanzee communities?

    Science.gov (United States)

    Kamilar, Jason M; Marshack, Joshua L

    2012-02-01

    Much attention has been paid to geographic variation in chimpanzee behavior, but few studies have applied quantitative techniques to explain this variation. Here, we apply methods typically utilized in macroecology to explain variation in the putative cultural traits of chimpanzees. We analyzed published data containing 39 behavioral traits from nine chimpanzee communities. We used a canonical correspondence analysis to examine the relative importance of environmental characteristics and geography, which may be a proxy for inter-community gene flow and/or social transmission, for explaining geographic variation in chimpanzee behavior. We found that geography, and longitude in particular, was the best predictor of behavioral variation. Chimpanzee communities in close longitudinal proximity to each other exhibit similar behavioral repertoires, independent of local ecological factors. No ecological variables were significantly related to behavioral variation. These results support the idea that inter-community dispersal patterns have played a major role in structuring behavioral variation. We cannot be certain whether behavioral variation has a genetic basis, is the result of innovation and diffusion, or a combination of the two. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Canonical Cortical Circuit Model Explains Rivalry, Intermittent Rivalry, and Rivalry Memory.

    Directory of Open Access Journals (Sweden)

    Shashaank Vattikuti

    2016-05-01

    Full Text Available It has been shown that the same canonical cortical circuit model with mutual inhibition and a fatigue process can explain perceptual rivalry and other neurophysiological responses to a range of static stimuli. However, it has been proposed that this model cannot explain responses to dynamic inputs such as found in intermittent rivalry and rivalry memory, where maintenance of a percept when the stimulus is absent is required. This challenges the universality of the basic canonical cortical circuit. Here, we show that by including an overlooked realistic small nonspecific background neural activity, the same basic model can reproduce intermittent rivalry and rivalry memory without compromising static rivalry and other cortical phenomena. The background activity induces a mutual-inhibition mechanism for short-term memory, which is robust to noise and where fine-tuning of recurrent excitation or inclusion of sub-threshold currents or synaptic facilitation is unnecessary. We prove existence conditions for the mechanism and show that it can explain experimental results from the quartet apparent motion illusion, which is a prototypical intermittent rivalry stimulus.

  20. Explaining resource consumption among non-normal neonates

    Science.gov (United States)

    Schwartz, Rachel M.; Michelman, Thomas; Pezzullo, John; Phibbs, Ciaran S.

    1991-01-01

    The adoption by Medicare in 1983 of prospective payment using diagnosis-related groups (DRGs) has stimulated research to develop case-mix grouping schemes that more accurately predict resource consumption by patients. In this article, the authors explore a new method designed to improve case-mix classification for newborns through the use of birth weight in combination with DRGs to adjust the unexplained case-mix severity. Although the findings are developmental in nature, they reveal that the model significantly improves our ability to explain resource use. PMID:10122360

  1. Explaining variation in Down's syndrome screening uptake

    DEFF Research Database (Denmark)

    Crombag, Neeltje M T H; Vellinga, Ynke E; Kluijfhout, Sandra A

    2014-01-01

    ), in an attempt to explain the observed variation in national uptake rates. METHODS: We used a mixed methods approach with an embedded design: a) documentary analysis and b) expert stakeholder analysis. National central statistical offices and legal documents were studied first to gain insight in demographic....... RESULTS: There were many similarities in the demographics, healthcare systems, government abortion legislation and Down's syndrome screening policy across the studied countries. However, the additional cost for Down's syndrome screening over and above standard antenatal care in the Netherlands...

  2. Microhabitat and Climatic Niche Change Explain Patterns of Diversification among Frog Families.

    Science.gov (United States)

    Moen, Daniel S; Wiens, John J

    2017-07-01

    A major goal of ecology and evolutionary biology is to explain patterns of species richness among clades. Differences in rates of net diversification (speciation minus extinction over time) may often explain these patterns, but the factors that drive variation in diversification rates remain uncertain. Three important candidates are climatic niche position (e.g., whether clades are primarily temperate or tropical), rates of climatic niche change among species within clades, and microhabitat (e.g., aquatic, terrestrial, arboreal). The first two factors have been tested separately in several studies, but the relative importance of all three is largely unknown. Here we explore the correlates of diversification among families of frogs, which collectively represent ∼88% of amphibian species. We assemble and analyze data on phylogeny, climate, and microhabitat for thousands of species. We find that the best-fitting phylogenetic multiple regression model includes all three types of variables: microhabitat, rates of climatic niche change, and climatic niche position. This model explains 67% of the variation in diversification rates among frog families, with arboreal microhabitat explaining ∼31%, niche rates ∼25%, and climatic niche position ∼11%. Surprisingly, we show that microhabitat can have a much stronger influence on diversification than climatic niche position or rates of climatic niche change.

  3. The boundaries of instance-based learning theory for explaining decisions from experience.

    Science.gov (United States)

    Gonzalez, Cleotilde

    2013-01-01

    Most demonstrations of how people make decisions in risky situations rely on decisions from description, where outcomes and their probabilities are explicitly stated. But recently, more attention has been given to decisions from experience where people discover these outcomes and probabilities through exploration. More importantly, risky behavior depends on how decisions are made (from description or experience), and although prospect theory explains decisions from description, a comprehensive model of decisions from experience is yet to be found. Instance-based learning theory (IBLT) explains how decisions are made from experience through interactions with dynamic environments (Gonzalez et al., 2003). The theory has shown robust explanations of behavior across multiple tasks and contexts, but it is becoming unclear what the theory is able to explain and what it does not. The goal of this chapter is to start addressing this problem. I will introduce IBLT and a recent cognitive model based on this theory: the IBL model of repeated binary choice; then I will discuss the phenomena that the IBL model explains and those that the model does not. The argument is for the theory's robustness but also for clarity in terms of concrete effects that the theory can or cannot account for. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Explaining Cross-Country Differences in Attitudes Towards Immigration in the EU-15

    DEFF Research Database (Denmark)

    Malchow-Møller, Nikolaj; Munch, Jakob Roland; Schroll, Sanne

    2009-01-01

    In this paper, we use data from the first two rounds of the European Social Survey to analyze the extent to which differences in average attitudes towards immigration across the EU-15 countries may be explained by differences in socioeconomic characteristics and individually perceived consequences...... of immigration, using an extension of a decomposition technique developed by Fairlie (2005). We find that despite the significant effects of socioeconomic characteristics on attitudes, differences in the distributions of these characteristics can only explain a modest share of the cross-country variation...... in average attitudes. A larger part can be explained by differences in perceived consequences of immigration, but the main part is still left unexplained. Apart from providing useful input for policy makers working in the area of immigration policy, this raises a number of questions for further research...

  5. Explaining Cross-Country Differences in Attitudes towards Immigration in the EU-15

    DEFF Research Database (Denmark)

    Malchow-Møller, Nikolaj; Munch, Jakob Roland; Schroll, Sanne

    2007-01-01

    In this paper, we use data from the first two rounds of the European Social Survey to analyze the extent to which differences in average attitudes towards immigration across the EU-15 countries may be explained by differences in socioeconomic characteristics and individually perceived consequences...... of immigration, using an extension of a decomposition technique developed by Fairlie (2005). We find that despite the significant effects of socioeconomic characteristics on attitudes, differences in the distributions of these characteristics can only explain a modest share of the cross-country variation...... in average attitudes. A larger part can be explained by differences in perceived consequences of immigration, but the main part is still left unexplained. Apart from providing useful input for policy makers working in the area of immigration policy, this raises a number of questions for further research...

  6. Explaining Cross-Country Differences in Attitudes Towards Immigration in the EU-15

    DEFF Research Database (Denmark)

    Malchow-Møller, Nikolaj; Munch, Jakob Roland; Skaksen, Jan Rose

    In this paper, we use data from the first two rounds of the European Social Survey to analyse the extent to which differences in average attitudes towards immigration across the EU-15 countries may be explained by differences in socioeconomic characteristics and individually perceived consequences...... of immigration, using an extension of a decomposition technique developed by Fairlie (2005). We find that despite the significant effects of socioeconomic characteristics on attitudes, differences in the distributions of these characteristics can only explain a modest share of the cross-country variation...... in average attitudes. A larger part can be explained by differences in perceived consequences of immigration, but the main part is still left unexplained. Apart from providing useful input for policy makers working in the area of immigration policy, this raises a number of questions for further research...

  7. Imitation explains the propagation, not the stability of animal culture.

    Science.gov (United States)

    Claidière, Nicolas; Sperber, Dan

    2010-02-22

    For acquired behaviour to count as cultural, two conditions must be met: it must propagate in a social group, and it must remain stable across generations in the process of propagation. It is commonly assumed that imitation is the mechanism that explains both the spread of animal culture and its stability. We review the literature on transmission chain studies in chimpanzees (Pan troglodytes) and other animals, and we use a formal model to argue that imitation, which may well play a major role in the propagation of animal culture, cannot be considered faithful enough to explain its stability. We consider the contribution that other psychological and ecological factors might make to the stability of animal culture observed in the wild.

  8. Explaining e-business adoption - Innovation & entrepreneurship in Dutch SMEs

    NARCIS (Netherlands)

    van der Veen, M.

    2005-01-01

    Explaining e-business adoptionThis dissertation deals with the explanation of e-business adoption in Dutch small and medium sized enterprises. The adoption of e-business plays an important part in making existing business more efficient and effective. Moreover, it is a tool for business development

  9. Explaining dehumanization among children: the interspecies model of prejudice.

    Science.gov (United States)

    Costello, Kimberly; Hodson, Gordon

    2014-03-01

    Although many theoretical approaches have emerged to explain prejudices expressed by children, none incorporate outgroup dehumanization, a key predictor of prejudice among adults. According to the Interspecies Model of Prejudice, beliefs in the human-animal divide facilitate outgroup prejudice through fostering animalistic dehumanization (Costello & Hodson, 2010). In the present investigation, White children attributed Black children fewer 'uniquely human' characteristics, representing the first systematic evidence of racial dehumanization among children (Studies 1 and 2). In Study 2, path analyses supported the Interspecies Model of Prejudice: children's human-animal divide beliefs predicted greater racial prejudice, an effect explained by heightened racial dehumanization. Similar patterns emerged among parents. Furthermore, parent Social Dominance Orientation predicted child prejudice indirectly through children's endorsement of a hierarchical human-animal divide and subsequent dehumanizing tendencies. Encouragingly, children's human-animal divide perceptions were malleable to an experimental prime highlighting animal-human similarity. Implications for prejudice interventions are considered. © 2012 The British Psychological Society.

  10. Explaining judicial corruption in the courts of Chile, Peru and Ecuador

    Directory of Open Access Journals (Sweden)

    Santiago Basabe-Serrano

    2013-07-01

    Full Text Available This article identifies the main variables that explain judicial corruption in Chile, Peru, and Ecuador. Improving the current methodological strategies used to measure judicial corruption and incorporating endogenous and exogenous variables in the model, this article argues that legal training of the judges, respect for the judicial career, and the fragmentation of political power explain different degrees of judicial corruption. Through a comparative diachronic and synchronic research design of Chile, Peru and Ecuador, the article shows institutional designs with more legal steps will be more inclined to illegal payments or other types of judicial corruption.

  11. Explaining R{sub D}{sup {sub (}{sub *}{sub )}} with leptoquarks and flavor symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Schoenwald, Kay [TU Dortmund (Germany)

    2016-07-01

    Recently LHCb confirmed the anomalies in R{sub D}{sup {sub (}{sub *}{sub )}} previously measured by BaBar and Belle. We use flavor symmetries capable of explaining the observed mixing in the quark and lepton sector to constrain leptoquark couplings and study whether this models can explain the anomalies in R{sub D}{sup {sub (}{sub *}{sub )}}.

  12. Explaining differences between hospitals in number of organ donors.

    NARCIS (Netherlands)

    Friele, R.D.; Coppen, R.; Marquet, R.L.; Gevers, J.K.M.

    2006-01-01

    The shortage of donor organs calls for a careful examination of all improvement options. In this study, 80 Dutch hospitals were compared. They provided 868 donors in a 5-year period, constituting 91% of all donors in that period in The Netherlands. Multilevel regression analysis was used to explain

  13. Which Mechanisms Explain Monetary Returns to International Student Mobility?

    Science.gov (United States)

    Kratz, Fabian; Netz, Nicolai

    2018-01-01

    The authors develop a conceptual framework explaining monetary returns to international student mobility (ISM). Based on data from two German graduate panel surveys, they test this framework using growth curve models and Oaxaca-Blinder decompositions. The results indicate that ISM-experienced graduates enjoy a steeper wage growth after graduation…

  14. Can selection explain the protective effects of farming on asthma?

    Directory of Open Access Journals (Sweden)

    Wijnand Eduard

    2015-09-01

    No healthy worker selection into farming was observed and changes in asthma prevalence due to early retirement were small. Selection effects are therefore unlikely to explain the protective effects of farming on asthma.

  15. Explaining variation in the uptake of HPV vaccination in England

    Directory of Open Access Journals (Sweden)

    Whynes David K

    2011-03-01

    Full Text Available Abstract Background In England, two national programmes of HPV vaccination for girls have been instituted, a routine programme for 12- and 13-year-olds and a catch-up programme for 17- and 18-year-olds. Uptake rates across the country have been far from uniform, and this research sought to identify factors explaining the variation in uptake by locality. Methods An association between uptake, deprivation and ethnic background had been established in pilot research. The present analysis was conducted at an aggregate, Primary Care Trust (PCT, level for the first year of the programmes. Published measures of HPV vaccination uptake, material deprivation, ethnic composition of PCT populations, primary care quality, and uptake of cervical screening and of other childhood immunisations were collated. Strong evidence of collinearity amongst the explanatory variables required a factor analysis to be undertaken. This provided four independent factors, used thereafter in regression models to explain uptake by PCT. Results The factor analysis revealed that ethnic composition was associated with attitudes towards cervical screening and other childhood vaccinations, whilst material deprivation and quality of primary care were orthogonal. Ethnic composition, early childhood vaccination, cervical screening and primary care quality were found to be influential in predicting uptake in both the routine and the catch-up cohorts, although with a lower degree of confidence in the case of the last two independent variables. Lower primary care quality was significant in explaining a greater fall in vaccination uptake between the first two doses in the catch-up cohort. Greater deprivation was a significant explanatory factor for both uptake and the fall in uptake between doses for the catch-up cohort but not for uptake in the routine cohort. Conclusion These results for uptake of the first year of the national programme using aggregate data corroborate findings from

  16. EVE: Explainable Vector Based Embedding Technique Using Wikipedia

    OpenAIRE

    Qureshi, M. Atif; Greene, Derek

    2017-01-01

    We present an unsupervised explainable word embedding technique, called EVE, which is built upon the structure of Wikipedia. The proposed model defines the dimensions of a semantic vector representing a word using human-readable labels, thereby it readily interpretable. Specifically, each vector is constructed using the Wikipedia category graph structure together with the Wikipedia article link structure. To test the effectiveness of the proposed word embedding model, we consider its usefulne...

  17. Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by Emiliania huxleyi

    Directory of Open Access Journals (Sweden)

    G. M. Weiss

    2017-12-01

    Full Text Available Over the last decade, hydrogen isotopes of long-chain alkenones have been shown to be a promising proxy for reconstructing paleo sea surface salinity due to a strong hydrogen isotope fractionation response to salinity across different environmental conditions. However, to date, the decoupling of the effects of alkalinity and salinity, parameters that co-vary in the surface ocean, on hydrogen isotope fractionation of alkenones has not been assessed. Furthermore, as the alkenone-producing haptophyte, Emiliania huxleyi, is known to grow in large blooms under high light intensities, the effect of salinity on hydrogen isotope fractionation under these high irradiances is important to constrain before using δDC37 to reconstruct paleosalinity. Batch cultures of the marine haptophyte E. huxleyi strain CCMP 1516 were grown to investigate the hydrogen isotope fractionation response to salinity at high light intensity and independently assess the effects of salinity and alkalinity under low-light conditions. Our results suggest that alkalinity does not significantly influence hydrogen isotope fractionation of alkenones, but salinity does have a strong effect. Additionally, no significant difference was observed between the fractionation responses to salinity recorded in alkenones grown under both high- and low-light conditions. Comparison with previous studies suggests that the fractionation response to salinity in culture is similar under different environmental conditions, strengthening the use of hydrogen isotope fractionation as a paleosalinity proxy.

  18. Effects of alkalinity and salinity at low and high light intensity on hydrogen isotope fractionation of long-chain alkenones produced by Emiliania huxleyi

    Science.gov (United States)

    Weiss, Gabriella M.; Pfannerstill, Eva Y.; Schouten, Stefan; Sinninghe Damsté, Jaap S.; van der Meer, Marcel T. J.

    2017-12-01

    Over the last decade, hydrogen isotopes of long-chain alkenones have been shown to be a promising proxy for reconstructing paleo sea surface salinity due to a strong hydrogen isotope fractionation response to salinity across different environmental conditions. However, to date, the decoupling of the effects of alkalinity and salinity, parameters that co-vary in the surface ocean, on hydrogen isotope fractionation of alkenones has not been assessed. Furthermore, as the alkenone-producing haptophyte, Emiliania huxleyi, is known to grow in large blooms under high light intensities, the effect of salinity on hydrogen isotope fractionation under these high irradiances is important to constrain before using δDC37 to reconstruct paleosalinity. Batch cultures of the marine haptophyte E. huxleyi strain CCMP 1516 were grown to investigate the hydrogen isotope fractionation response to salinity at high light intensity and independently assess the effects of salinity and alkalinity under low-light conditions. Our results suggest that alkalinity does not significantly influence hydrogen isotope fractionation of alkenones, but salinity does have a strong effect. Additionally, no significant difference was observed between the fractionation responses to salinity recorded in alkenones grown under both high- and low-light conditions. Comparison with previous studies suggests that the fractionation response to salinity in culture is similar under different environmental conditions, strengthening the use of hydrogen isotope fractionation as a paleosalinity proxy.

  19. Explaining regional variation in home care use by demand and supply variables.

    Science.gov (United States)

    van Noort, Olivier; Schotanus, Fredo; van de Klundert, Joris; Telgen, Jan

    2018-02-01

    In the Netherlands, home care services like district nursing and personal assistance are provided by private service provider organizations and covered by private health insurance companies which bear legal responsibility for purchasing these services. To improve value for money, their procurement increasingly replaces fee-for-service payments with population based budgets. Setting appropriate population budgets requires adaptation to the legitimate needs of the population, whereas historical costs are likely to be influenced by supply factors as well, not all of which are necessarily legitimate. Our purpose is to explain home care costs in terms of demand and supply factors. This allows for adjusting historical cost patterns when setting population based budgets. Using expenses claims of 60 Dutch municipalities, we analyze eight demand variables and five supply variables with a multiple regression model to explain variance in the number of clients per inhabitant, costs per client and costs per inhabitant. Our models explain 69% of variation in the number of clients per inhabitant, 28% of costs per client and 56% of costs per inhabitant using demand factors. Moreover, we find that supply factors explain an additional 17-23% of variation. Predictors of higher utilization are home care organizations that are integrated with intramural nursing homes, higher competition levels among home care organizations and the availability of complementary services. Copyright © 2017. Published by Elsevier B.V.

  20. Thrive or Survive? Explaining Variation in Economic Outcomes for Refugees

    Directory of Open Access Journals (Sweden)

    Alexander Betts

    2017-11-01

    Full Text Available In the context of protracted refugee situations, there has been a revival in concern among policymakers to transcend the so-called humanitarian-development divide and create greater opportunities for self-reliance. Yet, these discussions too often neglect an analytical focus on refugees’ own economic lives, and their own interactions with markets.Despite a growing literature on the economic lives of refugees, much of that work has lacked theory or data. The work that has been quantitative has generally focused on the economic impact of refugees on host countries rather than explaining variation in economic outcomes for refugees.  In order to explain variation in economic outcomes for refugees, this paper asks three questions about the economic lives of refugees: 1 what makes the economic lives of refugees distinctive from other populations; 2 what explains variation in refugees’ income levels; and 3 what role does entrepreneurship play in shaping refugees’ economic outcomes?In order to answer these questions, the paper draws upon extensive qualitative and quantitative research conducted in Uganda by the Humanitarian Innovation Project at Oxford University. The quantitative data set is based on a survey of 2,213 refugees in three types of contexts: urban (Kampala, protracted camps (Nakivale and Kyangwali settlements, and emergency camps (Rwamwanja. It supplements this with qualitative research from other parts of Africa and the Middle East. The economic lives of refugees are argued to be distinctive not because refugees are any different qua human beings but because they often occupy a distinctive institutional space. Following new institutional economics, the paper argues that “refugee economies” represent a distinctive analytical space insofar as refugees face different formal and informal institutional barriers and distortions in their economic lives compared to nationals or other migrants. Even within the same country, refugees

  1. Explaining University Students' Effective Use of E-Learning Platforms

    Science.gov (United States)

    Moreno, Valter; Cavazotte, Flavia; Alves, Isabela

    2017-01-01

    Students' success in e-learning programs depends on how they adopt and embed technology into their learning activities. Drawing on the Technology Acceptance Model, we propose a framework to explain students' intention to use e-learning platforms effectively, that is, their intention to fully exploit system's functionalities in leaning processes,…

  2. A Conceptual Characterization of Online Videos Explaining Natural Selection

    Science.gov (United States)

    Bohlin, Gustav; Göransson, Andreas; Höst, Gunnar E.; Tibell, Lena A. E.

    2017-01-01

    Educational videos on the Internet comprise a vast and highly diverse source of information. Online search engines facilitate access to numerous videos claiming to explain natural selection, but little is known about the degree to which the video content match key evolutionary content identified as important in evolution education research. In…

  3. Holography explained in the language of potential scattering

    International Nuclear Information System (INIS)

    Csonka, P.L.

    1978-04-01

    Holography is explained in the language of potential scattering kinematics (whereas usually the formalism of wave optics is used). This approach is probably more natural for those who were trained as atomic, nuclear, etc., physicists, but are now attracted by the possibility of x-ray holography. Classical optical instruments are hardly mentioned, and the approximations usually connected with them are not used. Many of the results derived in this report are not new. 5 figures

  4. Can the Theory of Motivation Explain Migration Decisions?

    OpenAIRE

    Natálie Reichlová

    2005-01-01

    According to Abraham Maslow's motivational theory, human action is motivated by five groups of human needs. The model introduced in this paper exploits Maslow's theory to explain migration flows between regions. In the model, movement from one place to another influences migrant's utility through three various ways. First, through change in wage caused by different wage levels in each location. Second, through changes in utility connected with individuals safety needs and finally, through dis...

  5. Explaining socioeconomic inequalities in exclusive breast feeding in Norway.

    Science.gov (United States)

    Bærug, Anne; Laake, Petter; Løland, Beate Fossum; Tylleskär, Thorkild; Tufte, Elisabeth; Fretheim, Atle

    2017-08-01

    In high-income countries, lower socioeconomic position is associated with lower rates of breast feeding, but it is unclear what factors explain this inequality. Our objective was to examine the association between socioeconomic position and exclusive breast feeding, and to explore whether socioeconomic inequality in exclusive breast feeding could be explained by other sociodemographic characteristics, for example, maternal age and parity, smoking habits, birth characteristics, quality of counselling and breastfeeding difficulties. We used data from a questionnaire sent to mothers when their infants were five completed months as part of a trial of a breastfeeding intervention in Norway. We used maternal education as an indicator of socioeconomic position. Analyses of 1598 mother-infant pairs were conducted using logistic regression to assess explanatory factors of educational inequalities in breast feeding. Socioeconomic inequalities in exclusive breast feeding were present from the beginning and persisted for five completed months, when 22% of the most educated mothers exclusively breast fed compared with 7% of the least educated mothers: OR 3.39 (95% CI 1.74 to 6.61). After adjustment for all potentially explanatory factors, the OR was reduced to 1.49 (95% CI 0.70 to 3.14). This decrease in educational inequality seemed to be mainly driven by sociodemographic factors, smoking habits and breastfeeding difficulties, in particular perceived milk insufficiency. Socioeconomic inequalities in exclusive breast feeding at 5 months were largely explained by sociodemographic factors, but also by modifiable factors, such as smoking habits and breastfeeding difficulties, which can be amenable to public health interventions. NCT01025362. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  6. Understanding Electrochemistry Concepts Using the Predict-Observe-Explain Strategy

    Science.gov (United States)

    Karamustafaoglu, Sevilay; Mamlok-Naaman, Rachel

    2015-01-01

    The current study deals with freshman students who study at the Department of Science at the Faculty of Education. The aim of the study was to investigate the effect of teaching electrochemistry concepts using Predict-Observe-Explain (POE) strategy. The study was quasi-experimental design using 20 students each in the experimental group (EG) and…

  7. Can neighborhoods explain racial/ethnic differences in adolescent inactivity?

    Science.gov (United States)

    Richmond, Tracy K; Field, Alison E; Rich, Michael

    2007-01-01

    To determine if neighborhoods and their attributes contribute to racial/ethnic disparities in adolescent inactivity. We undertook a cross-sectional analysis of the National Longitudinal Study of Adolescent Health (n = 17,007), a nationally representative school-based study in the United States. Stratifying by gender, we used multivariate linear regression and multi-level modeling to determine whether neighborhood of residence may partially explain racial/ethnic disparities in adolescent physical inactivity, defined as hours viewing television or videos/DVDs and/or playing computer/video games each week. Participants lived in largely segregated communities. Black and Hispanic adolescent girls reported higher levels of inactivity than White adolescent girls (21 vs. 15 vs. 13 hours/week, respectively, p violent crime in the neighborhood was associated with inactivity, despite the individual's perception of his/her neighborhood as safe not being predictive. Although inactivity varies by race/ethnicity and gender, only in Hispanic adolescent girls does neighborhood fully explain the differential use. Our findings suggest that approaches other than changing neighborhood characteristics are needed to eliminate racial/ethnic disparities in adolescent inactivity.

  8. Using Culture to Explain Behavior: An Integrative Cultural Approach

    Science.gov (United States)

    Shepherd, Hana R.; Stephens, Nicole M.

    2010-01-01

    While savings rates among low-income families vary greatly, a 2008 National Poverty Center report finds that over 40 percent of low-income families fail to save any money. For decades policy makers and social scientists have sought to explain this phenomenon. Even after accounting for the fact that low-income families have less money to save, why…

  9. Explaining Global Women's Empowerment Using Geographic Inquiry

    Science.gov (United States)

    Grubbs, Melanie R.

    2018-01-01

    It is difficult for students who are just being introduced to major geographical concepts to understand how relatively free countries like India or Mali can have such high levels of human rights abuses as child brides, dowry deaths, and domestic violence. Textbooks explain it and video clips show examples, but it still seems surreal to teenagers…

  10. Explaining socio-demographic differences in disengagement from sports in adolescence

    NARCIS (Netherlands)

    Prins, R.G.; Kamphuis, C.B.M.; van Empelen, P.; Beenackers, M.A.; Brug, J.; Mackenbach, J.P.; Oenema, A.

    2013-01-01

    Purpose: The purpose of this longitudinal study is to identify risk groups for disengagement from sports during adolescence. In addition, it will be explored whether cognitive and environmental factors can explain socio-demographic differences in disengagement from sports. Methods: Data were

  11. Explaining socio-demographic differences in disengagement from sports in adolescence

    NARCIS (Netherlands)

    Prins, R.G.; Kamphuis, C.B.M.; Empelen, P. van; Beenackers, M.A.; Brug, J.; Mackenbach, J.P.; Oenema, A.

    2013-01-01

    Purpose: The purpose of this longitudinal study is to identify risk groups for disengagement from sports during adolescence. In addition, it will be explored whether cognitive and environmental factors can explain socio-demographic differences in disengagement from sports. METHODS: Data were

  12. Explaining Choice and Share of Category Requirements of Biologic Meat

    NARCIS (Netherlands)

    P.C. Verhoef (Peter); K. Vlagsma-Brangule (Kristine)

    2003-01-01

    textabstractIn this paper we examine factors determining choice and consumption of biologic or organic meat. In our model explaining choice and share of category requirements, we consider economic/marketing variables (quality, price, and distribution), emotions (fear, empathy, andguilt), social

  13. Explaining gender differences in competitiveness: Gender-task stereotypes

    OpenAIRE

    Große, Niels Daniel; Riener, Gerhard

    2010-01-01

    Gender-specific patterns of self-selection into competitive and cooperative environments may have multiple reasons. One of the most prominent explanations to this point is, that there are inherent differences between men and women when it comes to preferences regarding competition. We take a different point of view and claim that gender-task stereotypes are able to explain a large part of the under-representation of women in tournament like environments. We conduct an experiment with a quanti...

  14. Do executive functions explain the covariance between internalizing and externalizing behaviors?

    Science.gov (United States)

    Hatoum, Alexander S; Rhee, Soo Hyun; Corley, Robin P; Hewitt, John K; Friedman, Naomi P

    2017-11-16

    This study examined whether executive functions (EFs) might be common features of internalizing and externalizing behavior problems across development. We examined relations between three EF latent variables (a common EF factor and factors specific to updating working memory and shifting sets), constructed from nine laboratory tasks administered at age 17, to latent growth intercept (capturing stability) and slope (capturing change) factors of teacher- and parent-reported internalizing and externalizing behaviors in 885 individual twins aged 7 to 16 years. We then estimated the proportion of intercept-intercept and slope-slope correlations predicted by EF as well as the association between EFs and a common psychopathology factor (P factor) estimated from all 9 years of internalizing and externalizing measures. Common EF was negatively associated with the intercepts of teacher-rated internalizing and externalizing behavior in males, and explained 32% of their covariance; in the P factor model, common EF was associated with the P factor in males. Shifting-specific was positively associated with the externalizing slope across sex. EFs did not explain covariation between parent-rated behaviors. These results suggest that EFs are associated with stable problem behavior variation, explain small proportions of covariance, and are a risk factor that that may depend on gender.

  15. Discovering and explaining work-family strategies of parents in Luxembourg

    NARCIS (Netherlands)

    Zhelyazkova, Nevena

    2014-01-01

    The presented analysis discovers and explains typical patterns of work-family reconciliation for parents who had a child in the same period (2003) and in the same country (Luxembourg), thus facing the same macroeconomic and institutional conditions. Work-family trajectories are reconstructed as

  16. Explaining the R_K and R_{K^*} anomalies

    Science.gov (United States)

    Ghosh, Diptimoy

    2017-10-01

    Recent LHCb results on R_{K^*}, the ratio of the branching fractions of B → K^* μ ^+ μ ^- to that of B → K^* e^+ e^-, for the dilepton invariant mass bins q^2 ≡ m_{ℓ ℓ }^2 = [0.045-1.1] GeV^2 and [1.1-6] GeV^2 show approximately 2.5 σ deviations from the corresponding Standard Model prediction in each of the bins. This, when combined with the measurement of R_K (q^2=[1-6] GeV^2), a similar ratio for the decay to a pseudo-scalar meson, highly suggests lepton non-universal new physics in semi-leptonic B meson decays. In this work, we perform a model independent analysis of these potential new physics signals and identify the operators that do the best job in satisfying all these measurements. We show that heavy new physics, giving rise to q^2 independent local 4-Fermi operators of scalar, pseudo-scalar, vector or axial-vector type, is unable to explain all the three measurements simultaneously, in particular R_{K^*} in the bin [0.045-1.1], within their experimental 1σ regions. We point out the possibility to explain R_{K^*} in the low bin by an additional light (≲ 20 {MeV}) vector boson with appropriate coupling strengths to (\\bar{b} s) and (\\bar{e} e).

  17. Mapping and explaining the use of the left-right divide

    Directory of Open Access Journals (Sweden)

    André Freire

    2013-12-01

    Full Text Available This study is about mapping and explaining the use of the Left-Right divide across 14 countries from 5 Continents and relies on the richness of the post electoral mass surveys from the Comparative National Election Project: 14 countries and 18 elections spread over 5 continents. The paper shows not only how extensively the LR divide is used in these 14 countries, but also explains variation across both individuals and countries in terms of the factors determining LR recognition and use. Overall, it is shown that, although seen world-wide, the LR divide (both for self-placement and party placement is more present in long consolidated and middle-aged democracies and countries with freer media systems than in new democracies and societies with less free media systems. In the case of parties LR placement, party size also counts: larger parties are more easily placed. Additionally, we also show that LR recognition is more socially and politically determined in long consolidated and middle-aged democracies and in countries with more freedom of the press than in new democracies and in systems with less free media system. These findings add to the existing knowledge about these topics because previous studies were either country/Continent specific, or, if global in nature, never invested in explaining individual and system variation across 14 from 5 Continents. Besides, these findings mean that in the long term probably the new democracies will converge with the long consolidated or middle-aged ones, but this is an empirical question to be researched in future studies.

  18. Khalid Alshibli explains MGM to Sean O'Keefe

    Science.gov (United States)

    2002-01-01

    Khalid Alshibli of Louisiana State University, project scientist for the Mechanics of Granular Materials (MGM-III) experiment, uses a jar of sand as he explains MGM to NASA Administrator Sean O'Keefe. A training model of an MGM test cell is in the foreground. The activity was part of the Space Research and You education event held by NASA's Office of Biological and Physical Research on June 25, 2002, in Arlington, VA, to highlight the research that will be conducted on STS-107.

  19. Mediating Factors Explaining the Association Between Sexual Minority Status and Dating Violence.

    Science.gov (United States)

    Martin-Storey, Alexa; Fromme, Kim

    2017-08-01

    Dating violence presents a serious threat for individual health and well-being. A growing body of literature suggests that starting in adolescence, individuals with sexual minority identities (e.g., individuals who identify as gay, lesbian, or bisexual) may be at an increased risk for dating violence compared with heterosexuals. Research has not, however, identified the mechanisms that explain this vulnerability. Using a diverse sample of young adults ( n = 2,474), the current study explored how minority stress theory, revictimization theory, sex of sexual partners, and risky sexual behavior explained differences in dating violence between sexual minority and heterosexual young adults. Initial analyses suggested higher rates of dating violence among individuals who identified as bisexual, and individuals who identified as gay or lesbian when compared with heterosexuals, and further found that these associations failed to differ across gender. When mediating and control variables were included in the analyses, however, the association between both sexual minority identities and higher levels of dating violence became nonsignificant. Of particular interest was the role of discrimination, which mediated the association between bisexual identity and dating violence. Other factors, including sex and number of sexual partners, alcohol use, and childhood maltreatment, were associated with higher rates of dating violence but did not significantly explain vulnerability among sexual minority individuals compared with their heterosexual peers. These findings suggest the importance of minority stress theory in explaining vulnerability to dating violence victimization among bisexuals in particular, and generally support the importance of sexual-minority specific variables in understanding risk for dating violence within this vulnerable population.

  20. Negative plant soil feedback explaining ring formation in clonal plants

    NARCIS (Netherlands)

    Carteni, F.; Marasco, A.; Bonanomi, G.; Mazzoleni, S.; Rietkerk, M.G.; Giannino, F.

    2012-01-01

    Ring shaped patches of clonal plants have been reported in different environments, but the mechanisms underlying such pattern formation are still poorly explained. Water depletion in the inner tussocks zone has been proposed as a possible cause, although ring patterns have been also observed in

  1. PISA and High-Performing Education Systems: Explaining Singapore's Education Success

    Science.gov (United States)

    Deng, Zongyi; Gopinathan, S.

    2016-01-01

    Singapore's remarkable performance in Programme for International Student Assessment (PISA) has placed it among the world's high-performing education systems (HPES). In the literature on HPES, its "secret formula" for education success is explained in terms of teacher quality, school leadership, system characteristics and educational…

  2. Suspicious minds: explaining political cynicism among political journalists in Europe

    NARCIS (Netherlands)

    van Dalen, A.; Albæk, E.; de Vreese, C.

    2011-01-01

    Critics claim that journalists spread a cynical view of politics, as their relation with politicians is characterized by mistrust and hyper-adversarialism. To gain an insight into how cynical journalists themselves are about politics and how this can be explained, this article investigates the role

  3. Explaining CMS lepton excesses with supersymmetry

    CERN Multimedia

    CERN. Geneva; Prof. Allanach, Benjamin

    2014-01-01

    1) Kostas Theofilatos will give an introduction to CMS result 2) Ben Allanach: Several CMS analyses involving di-leptons have recently reported small 2.4-2.8 sigma local excesses: nothing to get too excited about, but worth keeping an eye on nonetheless. In particular, a search in the $lljj p_T$(miss) channel, a search for $W_R$ in the $lljj$ channel and a di-leptoquark search in the $lljj$ channel and $ljj p_T$(miss) channel have all yielded small excesses. We interpret the first excess in the MSSM, showing that the interpretation is viable in terms of other constraints, despite only having squark masses of around 1 TeV. We can explain the last three excesses with a single R-parity violating coupling that predicts a non-zero contribution to the neutrinoless double beta decay rate.

  4. Incidental perifissural nodules on routine chest computed tomography. Lung cancer or not?

    Energy Technology Data Exchange (ETDEWEB)

    Mets, Onno M.; Veldhuis, Wouter B.; Jong, Pim A. de [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Chung, Kaman; Scholten, Ernst T.; Ginneken, Bram van [Radboud University Nijmegen Medical Centre, Diagnostic Image Analysis Group, Nijmegen (Netherlands); Prokop, M. [Radboud University Nijmegen Medical Centre, Department of Radiology, Nijmegen (Netherlands); Schaefer-Prokop, Cornelia M. [Radboud University Nijmegen Medical Centre, Diagnostic Image Analysis Group, Nijmegen (Netherlands); Meander Medical Center, Department of Radiology, Amersfoort (Netherlands)

    2018-03-15

    Perifissural nodules (PFNs) are a common finding on chest CT, and are thought to represent non-malignant lesions. However, data outside a lung cancer-screening setting are currently lacking. In a nested case-control design, out of a total cohort of 16,850 patients ≥ 40 years of age who underwent routine chest CT (2004-2012), 186 eligible subjects with incident lung cancer and 511 controls without were investigated. All non-calcified nodules ≥ 4 mm were semi-automatically annotated. Lung cancer location and subject characteristics were recorded. Cases (56 % male) had a median age of 64 years (IQR 59-70). Controls (60 % male) were slightly younger (p<0.01), median age of 61 years (IQR 51-70). A total of 262/1,278 (21 %) unique non-calcified nodules represented a PFN. None of these were traced to a lung malignancy over a median follow-up of around 4.5 years. PFNs were most often located in the lower lung zones (72 %, p<0.001). Median diameter was 4.6 mm (range: 4.0-8.1), volume 51 mm{sup 3} (range: 32-278). Some showed growth rates < 400 days. Our data show that incidental PFNs do not represent lung cancer in a routine care, heterogeneous population. This confirms prior screening-based results. (orig.)

  5. Epigenetics and obesity: a relationship waiting to be explained.

    Science.gov (United States)

    Symonds, Michael E; Budge, Helen; Frazier-Wood, Alexis C

    2013-01-01

    Obesity can have multifactorial causes that may change with development and are not simply attributable to one's genetic constitution. To date, expensive and laborious genome-wide association studies have only ascribed a small contribution of genetic variants to obesity. The emergence of the field of epigenetics now offers a new paradigm with which to study excess fat mass. Currently, however, there are no compelling epigenetic studies to explain the role of epigenetics in obesity, especially from a developmental perspective. It is clear that until there are advances in the understanding of the main mechanisms by which different fat types, i.e. brown, beige, and white, are established and how these differ between depots and species, population-based studies designed to determine specific aspects of epigenetics will be potentially limited. Obesity is a slowly evolving condition that is not simply explained by changes in the intake of one macronutrient. The latest advances in epigenetics, coupled with the establishment of relevant longitudinal models of obesity, which incorporate functionally relevant end points, may now permit the precise contribution of epigenetic modifications to excess fat mass to be effectively studied. © 2013 S. Karger AG, Basel.

  6. The fate of lipids during development and cold-storage of eggs in the laboratory-reared calanoid copepod, Acartia tonsa Dana, and in response to different algal diets

    DEFF Research Database (Denmark)

    Støttrup, Josianne; Bell, J.G.; Sargent, J.R.

    1999-01-01

    : the cryptophyte Rhodomonas baltica, the haptophyte Isochrysis galbana clone T- iso, the diatom Thalassiosira weissflogii and the dinoflagellate Heterocapsa triquetra. Further, the effect of cold storage of eggs on the lipid composition of the newly hatched nauplii was examined. During development, the fatty acid...... composition changes from a tendency towards high levels of long-chain polyunsaturated fatty acids in the early developmental stages towards a tendency to accumulate more saturated and monounsaturated fatty acids in the later developmental stages. However, the content and composition of polyunsaturated fatty...

  7. Explaining Racial Disparities in Infant Health in Brazil

    Science.gov (United States)

    Nyarko, Kwame A.; Lopez-Camelo, Jorge; Castilla, Eduardo E.

    2015-01-01

    Objectives. We sought to quantify how socioeconomic, health care, demographic, and geographic effects explain racial disparities in low birth weight (LBW) and preterm birth (PTB) rates in Brazil. Methods. We employed a sample of 8949 infants born between 1995 and 2009 in 15 cities and 7 provinces in Brazil. We focused on disparities in LBW (Public policies to improve children’s health should target prenatal care and geographic location differences to reduce health disparities between infants of African and European ancestries in Brazil. PMID:26313046

  8. Explaining pathological changes in axonal excitability through dynamical analysis of conductance-based models

    Science.gov (United States)

    Coggan, Jay S.; Ocker, Gabriel K.; Sejnowski, Terrence J.; Prescott, Steven A.

    2011-10-01

    Neurons rely on action potentials, or spikes, to relay information. Pathological changes in spike generation likely contribute to certain enigmatic features of neurological disease, like paroxysmal attacks of pain and muscle spasm. Paroxysmal symptoms are characterized by abrupt onset and short duration, and are associated with abnormal spiking although the exact pathophysiology remains unclear. To help decipher the biophysical basis for 'paroxysmal' spiking, we replicated afterdischarge (i.e. continued spiking after a brief stimulus) in a minimal conductance-based axon model. We then applied nonlinear dynamical analysis to explain the dynamical basis for initiation and termination of afterdischarge. A perturbation could abruptly switch the system between two (quasi-)stable attractor states: rest and repetitive spiking. This bistability was a consequence of slow positive feedback mediated by persistent inward current. Initiation of afterdischarge was explained by activation of the persistent inward current forcing the system to cross a saddle point that separates the basins of attraction associated with each attractor. Termination of afterdischarge was explained by the attractor associated with repetitive spiking being destroyed. This occurred when ultra-slow negative feedback, such as intracellular sodium accumulation, caused the saddle point and stable limit cycle to collide; in that regard, the active attractor is not truly stable when the slowest dynamics are taken into account. The model also explains other features of paroxysmal symptoms, including temporal summation and refractoriness.

  9. Wealth, wages and wedlock : Explaining the college gender gap reversal

    NARCIS (Netherlands)

    Reijnders, Laurie

    2018-01-01

    We study the role of changes in the wage structure and expectations about marriage in explaining the college gender gap reversal. With strongly diminishing marginal utility of wealth and in the presence of a gender wage gap, single women have a greater incentive than single men to invest in

  10. Explaining the Association between Music Training and Reading in Adults

    Science.gov (United States)

    Swaminathan, Swathi; Schellenberg, E. Glenn; Venkatesan, Kirthika

    2018-01-01

    We sought to clarify whether the positive association between music lessons and reading ability is explained better by shared resources for processing pitch and temporal information, or by general cognitive abilities. Participants were native and nonnative speakers of English with varying levels of music training. We measured reading ability…

  11. When apperceptive agnosia is explained by a deficit of primary visual processing.

    Science.gov (United States)

    Serino, Andrea; Cecere, Roberto; Dundon, Neil; Bertini, Caterina; Sanchez-Castaneda, Cristina; Làdavas, Elisabetta

    2014-03-01

    Visual agnosia is a deficit in shape perception, affecting figure, object, face and letter recognition. Agnosia is usually attributed to lesions to high-order modules of the visual system, which combine visual cues to represent the shape of objects. However, most of previously reported agnosia cases presented visual field (VF) defects and poor primary visual processing. The present case-study aims to verify whether form agnosia could be explained by a deficit in basic visual functions, rather that by a deficit in high-order shape recognition. Patient SDV suffered a bilateral lesion of the occipital cortex due to anoxia. When tested, he could navigate, interact with others, and was autonomous in daily life activities. However, he could not recognize objects from drawings and figures, read or recognize familiar faces. He was able to recognize objects by touch and people from their voice. Assessments of visual functions showed blindness at the centre of the VF, up to almost 5°, bilaterally, with better stimulus detection in the periphery. Colour and motion perception was preserved. Psychophysical experiments showed that SDV's visual recognition deficits were not explained by poor spatial acuity or by the crowding effect. Rather a severe deficit in line orientation processing might be a key mechanism explaining SDV's agnosia. Line orientation processing is a basic function of primary visual cortex neurons, necessary for detecting "edges" of visual stimuli to build up a "primal sketch" for object recognition. We propose, therefore, that some forms of visual agnosia may be explained by deficits in basic visual functions due to widespread lesions of the primary visual areas, affecting primary levels of visual processing. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Diagnostic Performance of Ultra-Low-Dose Computed Tomography for Detecting Asbestos-Related Pleuropulmonary Diseases: Prospective Study in a Screening Setting

    OpenAIRE

    Schaal, Marysa; Severac, Fran?ois; Labani, Aissam; Jeung, Mi-Young; Roy, Catherine; Ohana, Micka?l

    2016-01-01

    Objective To evaluate the diagnostic performance of Ultra-Low-Dose Chest CT (ULD CT) for the detection of any asbestos-related lesions (primary endpoint) and specific asbestos-related abnormalities, i.e. non-calcified and calcified pleural plaques, diffuse pleural thickening, asbestosis and significant lung nodules (secondary endpoints). Material and Methods 55 male patients (55.7?8.1 years old) with occupational asbestos exposure for at least 15 years and where CT screening was indicated wer...

  13. Explaining the democratic anchorage of governance networks

    DEFF Research Database (Denmark)

    Skelcher, Chris; Klijn, Erik-Hans; Kübler, Daniel

    2011-01-01

    Advances in understanding the democratic anchorage of governance networks require carefully designed and contextually grounded empirical analysis that take into account contextual factors. The article uses a conjectural framework to study the impact of the national democratic milieu...... on the relationship between network governance and representative institutions in four European countries: the United Kingdom, Switzerland, the Netherlands, and Denmark. The article shows that the distinction between majoritarian and consensus democracy as well as the varying strength of voluntary associations...... are important contextual factors that help explain cross-national differences in the relationship between governance networks and representative institutions. We conclude that a context of weak associationalism in majoritarian democracies facilitates the instrumentalization of networks by government actors...

  14. Can molecular cell biology explain chromosome motions?

    Directory of Open Access Journals (Sweden)

    Gagliardi L

    2011-05-01

    Full Text Available Abstract Background Mitotic chromosome motions have recently been correlated with electrostatic forces, but a lingering "molecular cell biology" paradigm persists, proposing binding and release proteins or molecular geometries for force generation. Results Pole-facing kinetochore plates manifest positive charges and interact with negatively charged microtubule ends providing the motive force for poleward chromosome motions by classical electrostatics. This conceptual scheme explains dynamic tracking/coupling of kinetochores to microtubules and the simultaneous depolymerization of kinetochore microtubules as poleward force is generated. Conclusion We question here why cells would prefer complex molecular mechanisms to move chromosomes when direct electrostatic interactions between known bound charge distributions can accomplish the same task much more simply.

  15. Can Science Explain the Human Mind? Intuitive Judgments About the Limits of Science.

    Science.gov (United States)

    Gottlieb, Sara; Lombrozo, Tania

    2018-01-01

    Can science explain romantic love, morality, and religious belief? We documented intuitive beliefs about the limits of science in explaining the human mind. We considered both epistemic evaluations (concerning whether science could possibly fully explain a given psychological phenomenon) and nonepistemic judgments (concerning whether scientific explanations for a given phenomenon would generate discomfort), and we identified factors that characterize phenomena judged to fall beyond the scope of science. Across six studies, we found that participants were more likely to judge scientific explanations for psychological phenomena to be impossible and uncomfortable when, among other factors, they support first-person, introspective access (e.g., feeling empathetic as opposed to reaching for objects), contribute to making humans exceptional (e.g., appreciating music as opposed to forgetfulness), and involve conscious will (e.g., acting immorally as opposed to having headaches). These judgments about the scope of science have implications for science education, policy, and the public reception of psychological science.

  16. Explaining the Effects of Communities of Pastoral Care for Students

    Science.gov (United States)

    Murphy, Joseph; Holste, Linda

    2016-01-01

    This article explains how communities of pastoral care work. It presents an empirically forged theory in action. We examined theoretical and empirical work across the targeted area of personalization for students. We also completed what Hallinger (2012) refers to as "exhaustive review" of the field of school improvement writ large. We…

  17. Recognizing, explaining and countering norm transgressive behaviour on social media

    NARCIS (Netherlands)

    Padje, E.D.H.

    2016-01-01

    In this thesis, it is researched how norm transgressive behaviour exhibited on the Dutch domains of social media can be recognized, explained and countered. An analysis of four comment threads is conducted, of which the comments can be found on the Facebook pages of three Dutch news sites and on a

  18. Explaining Self-Harm: Youth Cybertalk and Marginalized Sexualities and Genders

    Science.gov (United States)

    McDermott, Elizabeth; Roen, Katrina; Piela, Anna

    2015-01-01

    This study investigates self-harm among young lesbian, gay, bisexual, and trans (LGBT) people. Using qualitative virtual methods, we examined online forums to explore young LGBT people's cybertalk about emotional distress and self-harming. We investigated how youth explained the relationship between self-harm and sexuality and gender. We found…

  19. Extending Social Learning Theory to Explain Victimization Among Gang and Ex-Gang Offenders.

    Science.gov (United States)

    Gagnon, Analisa

    2018-03-01

    This study is among the first to extend and test social learning theory's ability to understand property and violent victimization. It specifically tests whether aspects of definitions, differential reinforcement, and differential association/modeling can explain the three types of victimization of gang members: actual experience, perception of likelihood, and fear. The sample consists of over 300 male and female gang members incarcerated in jails throughout Florida. The results show that all three types of victimization can be explained by the three aspects of social learning theory.

  20. Mesoscale distribution and functional diversity of picoeukaryotes in the first-year sea ice of the Canadian Arctic.

    Science.gov (United States)

    Piwosz, Kasia; Wiktor, Józef Maria; Niemi, Andrea; Tatarek, Agnieszka; Michel, Christine

    2013-08-01

    Sea ice, a characteristic feature of polar waters, is home to diverse microbial communities. Sea-ice picoeukaryotes (unicellular eukaryotes with cell size Arctic first-year sea ice. Here, we investigated the abundance of all picoeukaryotes, and of 11 groups (chlorophytes, cryptophytes, bolidophytes, haptophytes, Pavlovaphyceae, Phaeocystis spp., pedinellales, stramenopiles groups MAST-1, MAST-2 and MAST-6 and Syndiniales Group II) at 13 first-year sea-ice stations localized in Barrow Strait and in the vicinity of Cornwallis Island, Canadian Arctic Archipelago. We applied Catalyzed Reporter Deposition-Fluorescence In Situ Hybridization to identify selected groups at a single cell level. Pavlovaphyceae and stramenopiles from groups MAST-2 and MAST-6 were for the first time reported from sea ice. Total numbers of picoeukaryotes were significantly higher in the vicinity of Cornwallis Island than in Barrow Strait. Similar trend was observed for all the groups except for haptophytes. Chlorophytes and cryptophytes were the dominant plastidic, and MAST-2 most numerous aplastidic of all the groups investigated. Numbers of total picoeukaryotes, chlorophytes and MAST-2 stramenopiles were positively correlated with the thickness of snow cover. All studied algal and MAST groups fed on bacteria. Presence of picoeukaryotes from various trophic groups (mixotrophs, phagotrophic and parasitic heterotrophs) indicates the diverse ecological roles picoeukaryotes have in sea ice. Yet, >50% of total sea-ice picoeukaryote cells remained unidentified, highlighting the need for further study of functional and phylogenetic sea-ice diversity, to elucidate the risks posed by ongoing Arctic changes.

  1. Learning to Apply Models of Materials While Explaining Their Properties

    Science.gov (United States)

    Karpin, Tiia; Juuti, Kalle; Lavonen, Jari

    2014-01-01

    Background: Applying structural models is important to chemistry education at the upper secondary level, but it is considered one of the most difficult topics to learn. Purpose: This study analyses to what extent in designed lessons students learned to apply structural models in explaining the properties and behaviours of various materials.…

  2. Does Discrimination Explain High Risk of Depression among High-Income African American Men?

    Science.gov (United States)

    Assari, Shervin; Lankarani, Maryam Moghani; Caldwell, Cleopatra Howard

    2018-04-19

    Background: Higher socioeconomic status is known to decrease the risk for poor mental health overall. However, African American males of higher socioeconomic status (SES) are at an increased risk for having a major depressive episode (MDE). It is not known whether perceived discrimination (PD) explains this risk. The current study used nationally representative data to explore the role of PD in explaining the association between high-SES and having MDE among African American men. Methods: The National Survey of American Life (NSAL), 2003, included 4461 American adults including 1271 African American men. SES indicators (i.e., household income, educational attainment, employment status, and marital status) were the independent variables. 12-month MDE measured using the Composite International Diagnostic Interview (CIDI) was the outcome. Age, gender, and region were the covariates. PD was the potential mediator. For data analysis, we used logistic regression. Results: Among African American men, household income was positively associated with odds of 12-month MDE. The positive association between household income and odds of MDE remained unchanged after adding PD to the model, suggesting that PD may not explain why high-income African American men are at a higher risk of MDE. Conclusions: Perceived discrimination does not explain the increased risk for depression among African American males of higher SES. Future research should explore the role of other potential mechanisms such as stress, coping, social isolation, and/or negative social interaction that may increase psychological costs of upward social mobility for African American males.

  3. Interannual variability of net ecosystem productivity in forests is explained by carbon flux phenology in autumn

    DEFF Research Database (Denmark)

    Wu, Chaoyang; Chen, Xi Jing; Black, T. Andrew

    2013-01-01

    To investigate the importance of autumn phenology in controlling interannual variability of forest net ecosystem productivity (NEP) and to derive new phenological metrics to explain the interannual variability of NEP. North America and Europe. Flux data from nine deciduous broadleaf forests (DBF......, soil water content and precipitation, were also used to explain the phenological variations. We found that interannual variability of NEP can be largely explained by autumn phenology, i.e. the autumn lag. While variation in neither annual gross primary productivity (GPP) nor in annual ecosystem...

  4. Coin Tossing Explains the Activity of Opposing Microtubule Motors on Phagosomes.

    Science.gov (United States)

    Sanghavi, Paulomi; D'Souza, Ashwin; Rai, Ashim; Rai, Arpan; Padinhatheeri, Ranjith; Mallik, Roop

    2018-05-07

    How the opposing activity of kinesin and dynein motors generates polarized distribution of organelles inside cells is poorly understood and hotly debated [1, 2]. Possible explanations include stochastic mechanical competition [3, 4], coordinated regulation by motor-associated proteins [5-7], mechanical activation of motors [8], and lipid-induced organization [9]. Here, we address this question by using phagocytosed latex beads to generate early phagosomes (EPs) that move bidirectionally along microtubules (MTs) in an in vitro assay [9]. Dynein/kinesin activity on individual EPs is recorded as real-time force generation of the motors against an optical trap. Activity of one class of motors frequently coincides with, or is rapidly followed by opposite motors. This leads to frequent and rapid reversals of EPs in the trap. Remarkably, the choice between dynein and kinesin can be explained by the tossing of a coin. Opposing motors therefore appear to function stochastically and independently of each other, as also confirmed by observing no effect on kinesin function when dynein is inhibited on the EPs. A simple binomial probability calculation based on the geometry of EP-microtubule contact explains the observed activity of dynein and kinesin on phagosomes. This understanding of intracellular transport in terms of a hypothetical coin, if it holds true for other cargoes, provides a conceptual framework to explain the polarized localization of organelles inside cells. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  5. Can model-free reinforcement learning explain deontological moral judgments?

    Science.gov (United States)

    Ayars, Alisabeth

    2016-05-01

    Dual-systems frameworks propose that moral judgments are derived from both an immediate emotional response, and controlled/rational cognition. Recently Cushman (2013) proposed a new dual-system theory based on model-free and model-based reinforcement learning. Model-free learning attaches values to actions based on their history of reward and punishment, and explains some deontological, non-utilitarian judgments. Model-based learning involves the construction of a causal model of the world and allows for far-sighted planning; this form of learning fits well with utilitarian considerations that seek to maximize certain kinds of outcomes. I present three concerns regarding the use of model-free reinforcement learning to explain deontological moral judgment. First, many actions that humans find aversive from model-free learning are not judged to be morally wrong. Moral judgment must require something in addition to model-free learning. Second, there is a dearth of evidence for central predictions of the reinforcement account-e.g., that people with different reinforcement histories will, all else equal, make different moral judgments. Finally, to account for the effect of intention within the framework requires certain assumptions which lack support. These challenges are reasonable foci for future empirical/theoretical work on the model-free/model-based framework. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. An attempt to explain the uranium 238 effective capture integral discrepancy

    International Nuclear Information System (INIS)

    Tellier, Henry; Grandotto-Biettoli, Marc; Vanuxeem, Jacqueline

    1979-02-01

    Up to now, there was a discrepancy between the computed value and the measured value of the uranium 238 effective capture integral. The former has been always greater than the latter. For this reason, the reactor physicists have used an adjustment of the computed value. Nowadays the accuracy of the cross sections knowledge is increased and the reactors computation codes are almost exact. Such an adjustment is no more justified. Recently several new measurements of the resonance parameters were carried out and the use of a multilevel formalism was suggested to compute the uranium 238 cross sections. It is shown in this work that the simultaneous use of recent parameters and Reich and Moore formalism explain the discrepancy. For the thermal neutron reactors, two thirds of this discrepancy are explained by the neutron data and the last third by the multilevel formalism [fr

  7. Explaining the moral of the story.

    Science.gov (United States)

    Walker, Caren M; Lombrozo, Tania

    2017-10-01

    Although storybooks are often used as pedagogical tools for conveying moral lessons to children, the ability to spontaneously extract "the moral" of a story develops relatively late. Instead, children tend to represent stories at a concrete level - one that highlights surface features and understates more abstract themes. Here we examine the role of explanation in 5- and 6-year-old children's developing ability to learn the moral of a story. Two experiments demonstrate that, relative to a control condition, prompts to explain aspects of a story facilitate children's ability to override salient surface features, abstract the underlying moral, and generalize that moral to novel contexts. In some cases, generating an explanation is more effective than being explicitly told the moral of the story, as in a more traditional pedagogical exchange. These findings have implications for moral comprehension, the role of explanation in learning, and the development of abstract reasoning in early childhood. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Individual Movement Variability Magnitudes Are Explained by Cortical Neural Variability.

    Science.gov (United States)

    Haar, Shlomi; Donchin, Opher; Dinstein, Ilan

    2017-09-13

    Humans exhibit considerable motor variability even across trivial reaching movements. This variability can be separated into specific kinematic components such as extent and direction that are thought to be governed by distinct neural processes. Here, we report that individual subjects (males and females) exhibit different magnitudes of kinematic variability, which are consistent (within individual) across movements to different targets and regardless of which arm (right or left) was used to perform the movements. Simultaneous fMRI recordings revealed that the same subjects also exhibited different magnitudes of fMRI variability across movements in a variety of motor system areas. These fMRI variability magnitudes were also consistent across movements to different targets when performed with either arm. Cortical fMRI variability in the posterior-parietal cortex of individual subjects explained their movement-extent variability. This relationship was apparent only in posterior-parietal cortex and not in other motor system areas, thereby suggesting that individuals with more variable movement preparation exhibit larger kinematic variability. We therefore propose that neural and kinematic variability are reliable and interrelated individual characteristics that may predispose individual subjects to exhibit distinct motor capabilities. SIGNIFICANCE STATEMENT Neural activity and movement kinematics are remarkably variable. Although intertrial variability is rarely studied, here, we demonstrate that individual human subjects exhibit distinct magnitudes of neural and kinematic variability that are reproducible across movements to different targets and when performing these movements with either arm. Furthermore, when examining the relationship between cortical variability and movement variability, we find that cortical fMRI variability in parietal cortex of individual subjects explained their movement extent variability. This enabled us to explain why some subjects

  9. Does cultural integration explain a mental health advantage for adolescents?

    Science.gov (United States)

    Bhui, Kamaldeep S; Lenguerrand, Erik; Maynard, Maria J; Stansfeld, Stephen A; Harding, Seeromanie

    2012-06-01

    A mental health advantage has been observed among adolescents in urban areas. This prospective study tests whether cultural integration measured by cross-cultural friendships explains a mental health advantage for adolescents. A prospective cohort of adolescents was recruited from 51 secondary schools in 10 London boroughs. Cultural identity was assessed by friendship choices within and across ethnic groups. Cultural integration is one of four categories of cultural identity. Using gender-specific linear-mixed models we tested whether cultural integration explained a mental health advantage, and whether gender and age were influential. Demographic and other relevant factors, such as ethnic group, socio-economic status, family structure, parenting styles and perceived racism were also measured and entered into the models. Mental health was measured by the Strengths and Difficulties Questionnaire as a 'total difficulties score' and by classification as a 'probable clinical case'. A total of 6643 pupils in first and second years of secondary school (ages 11-13 years) took part in the baseline survey (2003/04) and 4785 took part in the follow-up survey in 2005-06. Overall mental health improved with age, more so in male rather than female students. Cultural integration (friendships with own and other ethnic groups) was associated with the lowest levels of mental health problems especially among male students. This effect was sustained irrespective of age, ethnicity and other potential explanatory variables. There was a mental health advantage among specific ethnic groups: Black Caribbean and Black African male students (Nigerian/Ghanaian origin) and female Indian students. This was not fully explained by cultural integration, although cultural integration was independently associated with better mental health. Cultural integration was associated with better mental health, independent of the mental health advantage found among specific ethnic groups: Black Caribbean and

  10. Does cultural integration explain a mental health advantage for adolescents?

    Science.gov (United States)

    Bhui, Kamaldeep S; Lenguerrand, Erik; Maynard, Maria J; Stansfeld, Stephen A; Harding, Seeromanie

    2012-01-01

    Background A mental health advantage has been observed among adolescents in urban areas. This prospective study tests whether cultural integration measured by cross-cultural friendships explains a mental health advantage for adolescents. Methods A prospective cohort of adolescents was recruited from 51 secondary schools in 10 London boroughs. Cultural identity was assessed by friendship choices within and across ethnic groups. Cultural integration is one of four categories of cultural identity. Using gender-specific linear-mixed models we tested whether cultural integration explained a mental health advantage, and whether gender and age were influential. Demographic and other relevant factors, such as ethnic group, socio-economic status, family structure, parenting styles and perceived racism were also measured and entered into the models. Mental health was measured by the Strengths and Difficulties Questionnaire as a ‘total difficulties score’ and by classification as a ‘probable clinical case’. Results A total of 6643 pupils in first and second years of secondary school (ages 11–13 years) took part in the baseline survey (2003/04) and 4785 took part in the follow-up survey in 2005–06. Overall mental health improved with age, more so in male rather than female students. Cultural integration (friendships with own and other ethnic groups) was associated with the lowest levels of mental health problems especially among male students. This effect was sustained irrespective of age, ethnicity and other potential explanatory variables. There was a mental health advantage among specific ethnic groups: Black Caribbean and Black African male students (Nigerian/Ghanaian origin) and female Indian students. This was not fully explained by cultural integration, although cultural integration was independently associated with better mental health. Conclusions Cultural integration was associated with better mental health, independent of the mental health advantage

  11. What We Don't Understand, We Explain to Each Other

    Science.gov (United States)

    Pines, David

    2015-01-01

    "What we don't understand, we explain to each other" was Robert Oppenheimer's 1948 description of theoretical physics as a profession. Because the phrase connects research, teaching, and learning, it seemed the right approach for the talk I gave to the AAPT [American Association of Physics Teachers] on receiving the 2013 J.D. Jackson…

  12. Explaining anomalies in intertemporal choice : a mental zooming theory

    OpenAIRE

    Holden, Stein Terje

    2014-01-01

    I present a theory that can explain hyperbolic discounting and magnitude effects in intertemporal choice. This approach builds on theories of narrow framing and reference dependence and expands these theories in a novel way by examining hidden mental zooming in base consumption adjustment in decisions regarding intertemporal prospects of varying magnitudes and time horizons. Data from a field experiment were used to assess the theory with an incentivecompatible multiple price list approach in...

  13. Do mirror neurons explain misattribution of emotions in music?

    Science.gov (United States)

    Gridley, Mark C; Hoff, Robert

    2006-04-01

    It is speculated that certain listeners' misattribution of anger in the music of avant garde jazz saxophonists could be explained by the activity of mirror neurons. There is a neurological basis for the human tendency to imitate what is perceived in another person. This may lead to an inference that whatever comparable activity would be required to achieve a similar condition in the imitator is the condition being experienced by the person being imitated.

  14. Island phytophagy: explaining the remarkable diversity of plant-feeding insects.

    Science.gov (United States)

    Joy, Jeffrey B; Crespi, Bernard J

    2012-08-22

    Plant-feeding insects have undergone unparalleled diversification among different plant taxa, yet explanations for variation in their diversity lack a quantitative, predictive framework. Island biogeographic theory has been applied to spatially discrete habitats but not to habitats, such as host plants, separated by genetic distance. We show that relationships between the diversity of gall-inducing flies and their host plants meet several fundamental predictions from island biogeographic theory. First, plant-taxon genetic distinctiveness, an integrator for long-term evolutionary history of plant lineages, is a significant predictor of variance in the diversity of gall-inducing flies among host-plant taxa. Second, range size and structural complexity also explain significant proportions of the variance in diversity of gall-inducing flies among different host-plant taxa. Third, as with other island systems, plant-lineage age does not predict species diversity. Island biogeographic theory, applied to habitats defined by genetic distance, provides a novel, comprehensive framework for analysing and explaining the diversity of plant-feeding insects and other host-specific taxa.

  15. Self-Interacting Dark Matter Can Explain Diverse Galactic Rotation Curves.

    Science.gov (United States)

    Kamada, Ayuki; Kaplinghat, Manoj; Pace, Andrew B; Yu, Hai-Bo

    2017-09-15

    The rotation curves of spiral galaxies exhibit a diversity that has been difficult to understand in the cold dark matter (CDM) paradigm. We show that the self-interacting dark matter (SIDM) model provides excellent fits to the rotation curves of a sample of galaxies with asymptotic velocities in the 25-300  km/s range that exemplify the full range of diversity. We assume only the halo concentration-mass relation predicted by the CDM model and a fixed value of the self-interaction cross section. In dark-matter-dominated galaxies, thermalization due to self-interactions creates large cores and reduces dark matter densities. In contrast, thermalization leads to denser and smaller cores in more luminous galaxies and naturally explains the flatness of rotation curves of the highly luminous galaxies at small radii. Our results demonstrate that the impact of the baryons on the SIDM halo profile and the scatter from the assembly history of halos as encoded in the concentration-mass relation can explain the diverse rotation curves of spiral galaxies.

  16. Use of retractors and explainers in charismatic rhetoric: the case of four American presidents

    Directory of Open Access Journals (Sweden)

    Iaroslav Kovalchuk

    2013-05-01

    Full Text Available This study examines the use of retractors and explainers in prepared political speeches of American charismatic presidents. It is based upon the results of psychological analysis of 24 speeches of John F. Kennedy, Ronald Reagan, Barack Obama, and Gerald Ford. The research shows that certain differences may be found in the use of explainers and retractors not along the axis “Charismatic versus Non-Charismatic Presidents”, but with regard to their party affiliation. Rhetoric of Democratic presidents (Kennedy, Obama is characterized by a more explanatory communication style than of Republican ones (Reagan, Ford, which results in respective differences in the use of explainers. As for the retractors, all the four presidents under study tend to use the category moderately, which reveals them as emotionally controlled individuals, able to reconsider their decisions if necessary.

  17. The attribution of work environment in explaining gender differences in long-term sickness absence

    DEFF Research Database (Denmark)

    Labriola, Merete; Holte, Kari Anne; Christensen, Karl Bang

    2011-01-01

    . Conclusion Differences in psychosocial work environments in terms of emotional demands, reward at work, management quality and role conflicts, explained roughly 30% of women's excess long-term sickness absence risk. Assuming women and men had identical working conditions would leave the larger part......Objectives To identify differences in risk of long-term sickness absence between female and male employees in Denmark and to examine to what extent differences could be explained by work environment factors. Methods A cohort of 5026 employees (49.1% women, mean age 40.4 years; 50.9% men, mean age....... Results 298 workers (5.9%) received sickness absence compensation for 8 weeks or more. Women had an excess risk of 37% compared to men, when adjusting for age, family status and socio-economic position. Physical work environment exposures could not explain this difference, whereas differences...

  18. Body Composition Explains Sex Differential in Physical Performance Among Older Adults

    NARCIS (Netherlands)

    Tseng, L.A.; Delmonico, M.J.; Visser, M.; Boudreau, R.M.; Goodpaster, B.H.; Schwartz, A.V.; Simonsick, E.M.; Satterfield, S.; Harris, T.; Newman, A.B.

    2014-01-01

    Background. Older women have higher percent body fat, poorer physical function, lower strength, and higher rates of nonfatal chronic conditions than men. We sought to determine whether these differences explained physical performance differences between men and women. Methods. Physical performance

  19. Why did I do that? : Explaining Actions Activated Outside of Awareness

    NARCIS (Netherlands)

    Gantman, A; Adriaanse, M.A.; Gollwitzer, P.M; Oettingen, G

    2017-01-01

    We review the latest research investigating how people explain their own actions when they have been activated nonconsciously. We will discuss evidence that when nonconsciously activated behavior is unexpected (e.g., normviolating, against self -standards), negative affect arises and triggers

  20. A Model of How Different Biology Experts Explain Molecular and Cellular Mechanisms

    Science.gov (United States)

    Trujillo, Caleb M.; Anderson, Trevor R.; Pelaez, Nancy J.

    2015-01-01

    Constructing explanations is an essential skill for all science learners. The goal of this project was to model the key components of expert explanation of molecular and cellular mechanisms. As such, we asked: What is an appropriate model of the components of explanation used by biology experts to explain molecular and cellular mechanisms? Do explanations made by experts from different biology subdisciplines at a university support the validity of this model? Guided by the modeling framework of R. S. Justi and J. K. Gilbert, the validity of an initial model was tested by asking seven biologists to explain a molecular mechanism of their choice. Data were collected from interviews, artifacts, and drawings, and then subjected to thematic analysis. We found that biologists explained the specific activities and organization of entities of the mechanism. In addition, they contextualized explanations according to their biological and social significance; integrated explanations with methods, instruments, and measurements; and used analogies and narrated stories. The derived methods, analogies, context, and how themes informed the development of our final MACH model of mechanistic explanations. Future research will test the potential of the MACH model as a guiding framework for instruction to enhance the quality of student explanations. PMID:25999313

  1. Science and Technology Pre-Service Teachers' Tendencies to Explain Vitality

    Science.gov (United States)

    Ozdemir, Oguz

    2012-01-01

    The present study was carried out to determine the Science and Technology pre-service teachers' tendencies to explain vitality in a university located in Southeast Anatolia of Turkey in 2010-2011 academic year. The data were collected through the administration of a questionnaire developed by the researcher to 1st and 4th year Science and…

  2. Does Discrimination Explain High Risk of Depression among High-Income African American Men?

    Directory of Open Access Journals (Sweden)

    Shervin Assari

    2018-04-01

    Full Text Available Background: Higher socioeconomic status is known to decrease the risk for poor mental health overall. However, African American males of higher socioeconomic status (SES are at an increased risk for having a major depressive episode (MDE. It is not known whether perceived discrimination (PD explains this risk. The current study used nationally representative data to explore the role of PD in explaining the association between high-SES and having MDE among African American men. Methods: The National Survey of American Life (NSAL, 2003, included 4461 American adults including 1271 African American men. SES indicators (i.e., household income, educational attainment, employment status, and marital status were the independent variables. 12-month MDE measured using the Composite International Diagnostic Interview (CIDI was the outcome. Age, gender, and region were the covariates. PD was the potential mediator. For data analysis, we used logistic regression. Results: Among African American men, household income was positively associated with odds of 12-month MDE. The positive association between household income and odds of MDE remained unchanged after adding PD to the model, suggesting that PD may not explain why high-income African American men are at a higher risk of MDE. Conclusions: Perceived discrimination does not explain the increased risk for depression among African American males of higher SES. Future research should explore the role of other potential mechanisms such as stress, coping, social isolation, and/or negative social interaction that may increase psychological costs of upward social mobility for African American males.

  3. Narrowing the Gap: Explaining the Increasing Competitiveness of the Venezuelan Opposition

    NARCIS (Netherlands)

    Krouwel, A.P.M.; Kutiyski, Y.

    2014-01-01

    This article seeks to explain why electoral support for the Venezuelan opposition has increased substantially, using Venezuelan public opinion survey data from LAPOP and an opt-in sample collected through the online vote advice application Brújula Presidencial Venezuela. It analyzes why Venezuelans

  4. How Much of Language Acquisition Does Operant Conditioning Explain?

    OpenAIRE

    Sturdy, Christopher B.; Nicoladis, Elena

    2017-01-01

    Since the 1950s, when Chomsky argued that Skinner’s arguments could not explain syntactic acquisition, psychologists have generally avoided explicitly invoking operant or instrumental conditioning as a learning mechanism for language among human children. In this article, we argue that this is a mistake. We focus on research that has been done on language learning in human infants and toddlers in order to illustrate our points. Researchers have ended up inventing learning mechanisms that, in ...

  5. Can Equity Volatility Explain the Global Loan Pricing Puzzle?

    OpenAIRE

    Lewis Gaul; Pinar Uysal

    2013-01-01

    This paper examines whether unobservable differences in firm volatility are responsible for the global loan pricing puzzle, which is the observation that corporate loan interest rates appear to be lower in Europe than in the United States. We analyze whether equity volatility, an error prone measure of firm volatility, can explain this difference in loan spreads. We show that using equity volatility in OLS regressions will result in biased and inconsistent estimates of the difference in U.S. ...

  6. A father effect explains sex-ratio bias.

    Science.gov (United States)

    Malo, Aurelio F; Martinez-Pastor, Felipe; Garcia-Gonzalez, Francisco; Garde, Julián; Ballou, Jonathan D; Lacy, Robert C

    2017-08-30

    Sex ratio allocation has important fitness consequences, and theory predicts that parents should adjust offspring sex ratio in cases where the fitness returns of producing male and female offspring vary. The ability of fathers to bias offspring sex ratios has traditionally been dismissed given the expectation of an equal proportion of X- and Y-chromosome-bearing sperm (CBS) in ejaculates due to segregation of sex chromosomes at meiosis. This expectation has been recently refuted. Here we used Peromyscus leucopus to demonstrate that sex ratio is explained by an exclusive effect of the father, and suggest a likely mechanism by which male-driven sex-ratio bias is attained. We identified a male sperm morphological marker that is associated with the mechanism leading to sex ratio bias; differences among males in the sperm nucleus area (a proxy for the sex chromosome that the sperm contains) explain 22% variation in litter sex ratio. We further show the role played by the sperm nucleus area as a mediator in the relationship between individual genetic variation and sex-ratio bias. Fathers with high levels of genetic variation had ejaculates with a higher proportion of sperm with small nuclei area. This, in turn, led to siring a higher proportion of sons (25% increase in sons per 0.1 decrease in the inbreeding coefficient). Our results reveal a plausible mechanism underlying unexplored male-driven sex-ratio biases. We also discuss why this pattern of paternal bias can be adaptive. This research puts to rest the idea that father contribution to sex ratio variation should be disregarded in vertebrates, and will stimulate research on evolutionary constraints to sex ratios-for example, whether fathers and mothers have divergent, coinciding, or neutral sex allocation interests. Finally, these results offer a potential explanation for those intriguing cases in which there are sex ratio biases, such as in humans. © 2017 The Author(s).

  7. Explaining evolution via constrained persistent perfect phylogeny

    Science.gov (United States)

    2014-01-01

    Background The perfect phylogeny is an often used model in phylogenetics since it provides an efficient basic procedure for representing the evolution of genomic binary characters in several frameworks, such as for example in haplotype inference. The model, which is conceptually the simplest, is based on the infinite sites assumption, that is no character can mutate more than once in the whole tree. A main open problem regarding the model is finding generalizations that retain the computational tractability of the original model but are more flexible in modeling biological data when the infinite site assumption is violated because of e.g. back mutations. A special case of back mutations that has been considered in the study of the evolution of protein domains (where a domain is acquired and then lost) is persistency, that is the fact that a character is allowed to return back to the ancestral state. In this model characters can be gained and lost at most once. In this paper we consider the computational problem of explaining binary data by the Persistent Perfect Phylogeny model (referred as PPP) and for this purpose we investigate the problem of reconstructing an evolution where some constraints are imposed on the paths of the tree. Results We define a natural generalization of the PPP problem obtained by requiring that for some pairs (character, species), neither the species nor any of its ancestors can have the character. In other words, some characters cannot be persistent for some species. This new problem is called Constrained PPP (CPPP). Based on a graph formulation of the CPPP problem, we are able to provide a polynomial time solution for the CPPP problem for matrices whose conflict graph has no edges. Using this result, we develop a parameterized algorithm for solving the CPPP problem where the parameter is the number of characters. Conclusions A preliminary experimental analysis shows that the constrained persistent perfect phylogeny model allows to

  8. Explaining life history variation in a changing climate across a species' range

    DEFF Research Database (Denmark)

    Neuheimer, Anna B.; MacKenzie, Brian R.

    2014-01-01

    Timing of reproduction greatly influences offspring success and resulting population production. Explaining and predicting species' dynamics necessitates disentangling the intrinsic (genotypic) and extrinsic (climatic) factors controlling reproductive timing. Here we explore temporal and spatial...... changes in spawning time for 21 populations of Atlantic cod (Gadus morhua) across the species' range (40 degrees to 80 degrees N). We estimate spawning time using a physiologically relevant metric that includes information on fish thermal history (degree-days, DD). First, we estimate spawning DD among...... years (within populations) to show how recent changes in spawning time can be explained by local changes in temperature. Second, we employ spawning DD to identify temperature-independent trends in spawning time among populations that are consistent with parallel adaptive evolution and the evolutionary...

  9. What explains high plant richness in East Asia? Time and diversification in the tribe Lysimachieae (Primulaceae).

    Science.gov (United States)

    Yan, Hai-Fei; Zhang, Cai-Yun; Anderberg, Arne A; Hao, Gang; Ge, Xue-Jun; Wiens, John J

    2018-04-17

    What causes the disparity in biodiversity among regions is a fundamental question in biogeography, ecology, and evolutionary biology. Evolutionary and biogeographic processes (speciation, extinction, dispersal) directly determine species richness patterns, and can be studied using integrative phylogenetic approaches. However, the strikingly high richness of East Asia relative to other Northern Hemisphere regions remains poorly understood from this perspective. Here, for the first time, we test two general hypotheses (older colonization time, faster diversification rate) to explain this pattern, using the plant tribe Lysimachieae (Primulaceae) as a model system. We generated a new time-calibrated phylogeny for Lysimachieae (13 genes, 126 species), to estimate colonization times and diversification rates for each region and to test the relative importance of these two factors for explaining regional richness patterns. We find that neither time nor diversification rates alone explain richness patterns among regions in Lysimachieae. Instead, a new index that combines both factors explains global richness patterns in the group and their high East Asian biodiversity. Based on our results from Lysimachieae, we suggest that the high richness of plants in East Asia may be explained by a combination of older colonization times and faster diversification rates in this region. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  10. Balancing friends and foes : Explaining advocacy styles at global diplomatic conferences

    NARCIS (Netherlands)

    Beyers, J.; Hanegraaff, M.

    The growing attempts by non-state interests to influence global policy processes has attracted much scholarly interest in recent years. One important question thereby is what characterizes and explains the interactions of non-state advocates with policymakers. In order to clarify this matter, we

  11. Explaining sex differences in chronic musculoskeletal pain in a general population.

    NARCIS (Netherlands)

    Wijnhoven, Hanneke A H; Vet, Henrica C W de; Picavet, H Susan J

    2006-01-01

    Many studies report a female predominance in the prevalence of chronic musculoskeletal pain (CMP) but the mechanisms explaining these sex differences are poorly understood. Data from a random postal questionnaire survey in the Dutch general population were used to examine whether sex differences in

  12. Explaining Career Decision-Making Self-Efficacy: Personality, Cognitions, and Cultural Mistrust

    Science.gov (United States)

    Bullock-Yowell, Emily; Andrews, Lindsay; Buzzetta, Mary E.

    2011-01-01

    The authors explore the hypothesis that career decision-making self-efficacy could be affected by negative career thoughts, Big Five personality factors, and cultural mistrust in a sample of African American and Caucasian college students. Findings demonstrated that negative career thinking, openness, and conscientiousness explained a significant…

  13. Explaining How to Play Real-Time Strategy Games

    Science.gov (United States)

    Metoyer, Ronald; Stumpf, Simone; Neumann, Christoph; Dodge, Jonathan; Cao, Jill; Schnabel, Aaron

    Real-time strategy games share many aspects with real situations in domains such as battle planning, air traffic control, and emergency response team management which makes them appealing test-beds for Artificial Intelligence (AI) and machine learning. End user annotations could help to provide supplemental information for learning algorithms, especially when training data is sparse. This paper presents a formative study to uncover how experienced users explain game play in real-time strategy games. We report the results of our analysis of explanations and discuss their characteristics that could support the design of systems for use by experienced real-time strategy game users in specifying or annotating strategy-oriented behavior.

  14. Possibility to explain the temperature distribution in sunspots by an anisotropic heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Eschrich, K O; Krause, F [Akademie der Wissenschaften der DDR, Potsdam. Zentralinstitut fuer Astrophysik

    1977-01-01

    Numerical solutions of a heat conduction problem in an anisotropic medium are used for a discussion of the possibility to explain the temperature distribution in sunspots and their environment. The anisotropy is assumed being due to the strong magnetic field in sunspots and the region below. This magnetic field forces the convection to take an anisotropic structure (two-dimensional turbulence) and thus the region gets anisotropic conduction properties, on the average. The discussion shows that the observed temperature profiles can be explained in the case the depth of the region of anisotropy is about as large as the diameter of the spot or larger.

  15. A simple model explaining super-resolution in absolute optical instruments

    Science.gov (United States)

    Leonhardt, Ulf; Sahebdivan, Sahar; Kogan, Alex; Tyc, Tomáš

    2015-05-01

    We develop a simple, one-dimensional model for super-resolution in absolute optical instruments that is able to describe the interplay between sources and detectors. Our model explains the subwavelength sensitivity of a point detector to a point source reported in previous computer simulations and experiments (Miñano 2011 New J. Phys.13 125009; Miñano 2014 New J. Phys.16 033015).

  16. Explaining excess morbidity amongst homeless shelter users

    DEFF Research Database (Denmark)

    Benjaminsen, Lars; Birkelund, Jesper Fels

    2018-01-01

    AIMS: This article analyses excess morbidity amongst homeless shelter users compared to the general Danish population. The study provides an extensive control for confounding and investigates to what extent excess morbidity is explained by homelessness or other risk factors. METHODS: Data set...... includes administrative micro-data for 4,068,926 Danes who were 23 years or older on 1 January 2007. Nationwide data on shelter use identified 14,730 individuals as shelter users from 2002 to 2006. Somatic diseases were measured from 2007 to 2011 through diagnosis data from hospital discharges. The risk...... of somatic diseases amongst shelter users was analysed through a multivariate model that decomposed the total effect into a direct effect and indirect effects mediated by other risk factors. RESULTS: The excess morbidity associated with shelter use is substantially lower than in studies that did not include...

  17. The Role of Colorism in Explaining African American Females' Suspension Risk

    Science.gov (United States)

    Blake, Jamilia J.; Keith, Verna M.; Luo, Wen; Le, Huong; Salter, Phia

    2017-01-01

    African American female students' elevated suspension risk has received national attention. Despite a number of studies documenting racial/ethnic disparities in African American females' school suspension risk, few investigations have attempted to explain why these disparities occur. The purpose of this study was to examine the role of colorism in…

  18. Time delay and noise explaining the behaviour of the cell growth in fermentation process

    Energy Technology Data Exchange (ETDEWEB)

    Ayuobi, Tawfiqullah; Rosli, Norhayati [Faculty of Industrial Sciences and Technology, Universiti Malaysia Pahang, Lebuhraya Tun Razak, 26300 Gambang, Pahang (Malaysia); Bahar, Arifah [Department of Mathematical Sciences, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Salleh, Madihah Md [Department of Biotechnology Industry, Faculty of Biosciences and Bioengineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia)

    2015-02-03

    This paper proposes to investigate the interplay between time delay and external noise in explaining the behaviour of the microbial growth in batch fermentation process. Time delay and noise are modelled jointly via stochastic delay differential equations (SDDEs). The typical behaviour of cell concentration in batch fermentation process under this model is investigated. Milstein scheme is applied for solving this model numerically. Simulation results illustrate the effects of time delay and external noise in explaining the lag and stationary phases, respectively for the cell growth of fermentation process.

  19. Time delay and noise explaining the behaviour of the cell growth in fermentation process

    Science.gov (United States)

    Ayuobi, Tawfiqullah; Rosli, Norhayati; Bahar, Arifah; Salleh, Madihah Md

    2015-02-01

    This paper proposes to investigate the interplay between time delay and external noise in explaining the behaviour of the microbial growth in batch fermentation process. Time delay and noise are modelled jointly via stochastic delay differential equations (SDDEs). The typical behaviour of cell concentration in batch fermentation process under this model is investigated. Milstein scheme is applied for solving this model numerically. Simulation results illustrate the effects of time delay and external noise in explaining the lag and stationary phases, respectively for the cell growth of fermentation process.

  20. Time delay and noise explaining the behaviour of the cell growth in fermentation process

    International Nuclear Information System (INIS)

    Ayuobi, Tawfiqullah; Rosli, Norhayati; Bahar, Arifah; Salleh, Madihah Md

    2015-01-01

    This paper proposes to investigate the interplay between time delay and external noise in explaining the behaviour of the microbial growth in batch fermentation process. Time delay and noise are modelled jointly via stochastic delay differential equations (SDDEs). The typical behaviour of cell concentration in batch fermentation process under this model is investigated. Milstein scheme is applied for solving this model numerically. Simulation results illustrate the effects of time delay and external noise in explaining the lag and stationary phases, respectively for the cell growth of fermentation process

  1. Explaining inequalities in women's mortality between U.S. States

    Directory of Open Access Journals (Sweden)

    Jennifer Karas Montez

    2016-12-01

    Full Text Available Inequalities in women's mortality between U.S. states are large and growing. It is unknown whether they reflect differences between states in their population characteristics, contextual characteristics, or both. This study systematically examines the large inequalities in women's mortality between U.S. states using a multilevel approach. It focuses on “fundamental” social determinants of mortality at the individual and state levels as potential explanations. We analyze data from the 2013 public-use National Longitudinal Mortality Study on women aged 45–89 years and estimate multilevel logistic regression models. The models include women's personal characteristics (age, race/ethnicity, education, employment, income, and marriage and states’ contextual characteristics (economic environment, social cohesion, sociopolitical orientation, physical infrastructure, and tobacco environment. We found that variation in women's mortality across states was significant (p<0.001. Adjusting for women's personal characteristics explained 30% of the variation. Additionally adjusting for states’ contextual characteristics explained 62% of the variation; the most important characteristics were social cohesion and economic conditions. No significant mortality differences between any two states remained after accounting for individual and contextual characteristics. Supplementary analyses of men indicate that state contexts have stronger and more pernicious consequences for women than men. Taken together, the findings underscore the importance of ‘bringing context back in’ and taking a multilevel approach when investigating geographic inequalities in U.S. mortality. Keywords: Mortality, Gender, Inequality, Social determinants, U.S. states, Multilevel

  2. Explaining the differential distribution of Clean Development Mechanism projects across host countries

    International Nuclear Information System (INIS)

    Winkelman, Andrew G.; Moore, Michael R.

    2011-01-01

    The Clean Development Mechanism (CDM) of the Kyoto Protocol represents an opportunity to involve all developing countries in the effort to reduce greenhouse gas emissions while also promoting sustainable development. To date, however, the majority of CDM projects have gone to emerging markets such as China, India, Brazil, and Mexico, while very few least developed countries have hosted projects. This paper investigates the differential distribution of CDM activities across countries. We develop a conceptual model for project profitability, which helps to identify potential country-level determinants of CDM activity. These potential determinants are employed as explanatory variables in regression analysis to explain the actual distribution of projects. Human capital and greenhouse gas emission levels influenced which countries have hosted projects and the amount of certified emission reductions (CER) created. Countries that offered growing markets for CDM co-products, such as electricity, were more likely to be CDM hosts, while economies with higher carbon intensity levels had greater CER production. These findings work against the least developed countries and help to explain their lack of CDM activity. - Research Highlights: → Regression models are used to explain the inter-country distribution of CDM projects. → Emissions and human capital are significant for hosting projects and CER creation. → An economy's emissions intensity is significant in determining CERs created. → Capacity building and electricity sector growth are significant in hosting projects. → The experience level for host countries in the CDM is significant for CER creation.

  3. Explaining consumer attitudes to genetic modification in food production

    DEFF Research Database (Denmark)

    Bredahl, Lone

    for explaining consumer attitudes to genetic modification in food production which builds on modern cognitive psychology and multi-attribute attitude theory. In addition, the paper introduces the empirical research which is undertaken at present to validate and estimate the parameters of the model by means......Consumers have not had many possibilities yet for seeking out, buying and consuming genetically modified food products. However, for various reasons consumer attitude formation with regard to these products is likely to be complex and closely related to personal values. The paper presents a model...

  4. Explaining the so-called 'price premium' in oil markets

    International Nuclear Information System (INIS)

    Merino, A.; Ortiz, A.

    2005-01-01

    This paper explores the information content of several variables on the so-called ''oil price premium over fundamentals''. We define this premium as the difference between the market oil price and the estimated price consistent with the OECD's relative industry stock level. By using Granger causality tests and extended regressions we test the systematic ability of a broad set of variables to explain the premium. We find that speculation in the oil market - measured by non-commercial long positions - can improve the traditional model, reducing the premium significantly during some parts of the sample. (author)

  5. Is Wagner’s theory relevant in explaining health expenditure dynamics in Botswana?

    Directory of Open Access Journals (Sweden)

    Kunofiwa Tsaurai

    2014-11-01

    Full Text Available This study tests the relevance of the Wagner’s theory in explaining the health expenditure in Botswana. There is no consensus yet when it comes to the causality relationship between health expenditure and economy. At the moment, there are four dominant schools of thought explaining the causality relationship between health expenditure and economy. The first school of thought is that health expenditure spurs the economy whilst the second school of thought says that the economy drives health expenditure. The third school of thought maintains that there is a feedback effect between health expenditure and the economy whilst the fourth mentions that there is no causality at all between the two variables. However, this study found out that there is no causality relationship between health expenditure and GDP in Botswana thereby dismissing the relevance of the Wagner’s theory.

  6. Coal liquefaction policy in China: Explaining the policy reversal since 2006

    International Nuclear Information System (INIS)

    Rong Fang; Victor, David G.

    2011-01-01

    China has emerged as a leader in coal liquefaction. While the country's abundant coal resources and acute concerns about oil security help explain China's interest in liquefaction, the driving forces for this industry are complicated and policy has been inconsistent. Since 2006 Beijing has tried to slow down the development of liquefaction; even as China has become more dependent on imported oil, the central government has been wary about the large impact of liquefaction technologies on scarce resources such as water. However, local government officials in coal rich areas have strong incentives to pour investment into the technology, which helps explain the uneven development and policy. The future of coal liquefaction will depend on how these forces unfold along with major Beijing-led reforms in the Chinese coal industry, which is closing smaller mines and favoring the emergence of larger coal producing firms. Those reforms will have mixed effects on liquefaction. They temporarily contribute to higher prices for coal while over the longer term creating coal companies that have much greater financial and technical skills needed to deploy technologies such as coal liquefaction at a scale needed if this energy pathway is to be competitive with conventional sources of liquid fuel. - Highlights: ► We explain swings in Chinese policy on coal liquefaction, a possible substitute for imported oil. ► Since 2006 Beijing's support has waned due to fears about environmental impacts and cost of liquefaction. ► Local governments in some coal rich regions remain strongly supportive. ► Volatile oil prices and rising coal prices make this industry more risky than previously thought. ► Consolidation of the coal industry will have mixed effects on viability of liquefaction projects.

  7. White matter tract network disruption explains reduced conscientiousness in multiple sclerosis.

    Science.gov (United States)

    Fuchs, Tom A; Dwyer, Michael G; Kuceyeski, Amy; Choudhery, Sanjeevani; Carolus, Keith; Li, Xian; Mallory, Matthew; Weinstock-Guttman, Bianca; Jakimovski, Dejan; Ramasamy, Deepa; Zivadinov, Robert; Benedict, Ralph H B

    2018-05-08

    Quantifying white matter (WM) tract disruption in people with multiple sclerosis (PwMS) provides a novel means for investigating the relationship between defective network connectivity and clinical markers. PwMS exhibit perturbations in personality, where decreased Conscientiousness is particularly prominent. This trait deficit influences disease trajectory and functional outcomes such as work capacity. We aimed to identify patterns of WM tract disruption related to decreased Conscientiousness in PwMS. Personality assessment and brain MRI were obtained in 133 PwMS and 49 age- and sex-matched healthy controls (HC). Lesion maps were applied to determine the severity of WM tract disruption between pairs of gray matter regions. Next, the Network-Based-Statistics tool was applied to identify structural networks whose disruption negatively correlates with Conscientiousness. Finally, to determine whether these networks explain unique variance above conventional MRI measures and cognition, regression models were applied controlling for age, sex, brain volume, T2-lesion volume, and cognition. Relative to HCs, PwMS exhibited lower Conscientiousness and slowed cognitive processing speed (p = .025, p = .006). Lower Conscientiousness in PwMS was significantly associated with WM tract disruption between frontal, frontal-parietal, and frontal-cingulate pathways in the left (p = .02) and right (p = .01) hemisphere. The mean disruption of these pathways explained unique additive variance in Conscientiousness, after accounting for conventional MRI markers of pathology and cognition (ΔR 2  = .049, p = .029). Damage to WM tracts between frontal, frontal-parietal, and frontal-cingulate cortical regions is significantly correlated with reduced Conscientiousness in PwMS. Tract disruption within these networks explains decreased Conscientiousness observed in PwMS as compared with HCs. © 2018 Wiley Periodicals, Inc.

  8. Explaining fast radio bursts through Dicke's superradiance

    Science.gov (United States)

    Houde, Martin; Mathews, Abhilash; Rajabi, Fereshteh

    2018-03-01

    Fast radio bursts (FRBs), characterized by strong bursts of radiation intensity at radio wavelengths lasting on the order of a millisecond, have yet to be firmly associated with a family, or families, of astronomical sources. It follows that despite the large number of proposed models, no well-defined physical process has been identified to explain this phenomenon. In this paper, we demonstrate how Dicke's superradiance, for which evidence has recently been found in the interstellar medium, can account for the characteristics associated with FRBs. Our analysis and modelling of previously detected FRBs suggest they could originate from regions in many ways similar to those known to harbour masers or megamasers, and result from the coherent radiation emanating from populations of molecules associated with large-scale entangled quantum mechanical states. We estimate this entanglement to involve as many as ˜1030 to ˜1032 molecules over distances spanning 100-1000 au.

  9. Testing and Explaining Differences in Common and Residual Factors Across Many Countries

    NARCIS (Netherlands)

    Jak, S.

    2017-01-01

    To make valid comparisons across countries, a measurement instrument needs to be measurement invariant across countries. The present article provides a nontechnical exposition of a recently proposed multilevel factor analysis approach to test measurement invariance across countries. It is explained

  10. Nutrient analysis explained for non-chemists by using interactive e-learning material

    NARCIS (Netherlands)

    Busstra, M.C.; Hulshof, P.J.M.; Houwen, J.; Elburg, L.; Hollman, P.C.H.

    2012-01-01

    The diverse educational and professional background of individuals involved in food composition data work presents challenges in their training. In particular, it is difficult to explain chemical analysis of nutrients to individuals lacking a background in chemistry. Therefore an interactive

  11. What Explains the Survival Gap of Pushed and Pulled Corporate Spin-offs?

    DEFF Research Database (Denmark)

    Rocha, Vera; Carneiro, Anabela; Varum, Celeste

    2015-01-01

    Unconditionally, pushed spin-offs are found to survive longer than their pulled counterparts. Using matched employer-employee data and novel multivariate decomposition techniques, we show that pushed spin-offs’ relative survival advantage is mostly explained by their larger human capital endowments...

  12. How Much Is Enough? Explaining the Continuous Transparency Conflict in TTIP

    Directory of Open Access Journals (Sweden)

    Niels Gheyle

    2017-09-01

    Full Text Available Transparency has been a central issue in the debate regarding the Transatlantic Trade and Investment Partnership (TTIP, especially on the side of the European Union (EU. The lack of transparency in the negotiating process has been one of the main criticisms of civil society organizations (CSOs. The European Commission (EC has tried to gain support for the negotiations through various ‘transparency initiatives’. Nonetheless, criticism by CSOs with regard to TTIP in general and the lack of transparency in specific remained prevalent. In this article, we explain this gap between various transparency initiatives implemented by the EC in TTIP and the expectations on the side of European CSOs. We perform a content analysis of position papers on transparency produced by CSOs, mainly in response to a European Ombudsman consultation, complemented by a number of official documents and targeted interviews. We find that the gap between the TTIP transparency initiatives and the expectations of CSOs can be explained by different views on what constitutes legitimate trade governance, and the role of transparency, participation, and accountability herein.

  13. Explaining the relationship between religiousness and substance use: self-control matters.

    Science.gov (United States)

    DeWall, C Nathan; Pond, Richard S; Carter, Evan C; McCullough, Michael E; Lambert, Nathaniel M; Fincham, Frank D; Nezlek, John B

    2014-08-01

    Religiousness is reliably associated with lower substance use, but little research has examined whether self-control helps explain why religiousness predicts lower substance use. Building on prior theoretical work, our studies suggest that self-control mediates the relationship between religiousness and a variety of substance-use behaviors. Study 1 showed that daily prayer predicted lower alcohol use on subsequent days. In Study 2, religiousness related to lower alcohol use, which was mediated by self-control. Study 3 replicated this mediational pattern using a behavioral measure of self-control. Using a longitudinal design, Study 4 revealed that self-control mediated the relationship between religiousness and lower alcohol use 6 weeks later. Study 5 replicated this mediational pattern again and showed that it remained significant after controlling for trait mindfulness. Studies 6 and 7 replicated and extended these effects to both alcohol and various forms of drug use among community and cross-cultural adult samples. These findings offer novel evidence regarding the role of self-control in explaining why religiousness is associated with lower substance use.

  14. Selective Pressures Explain Differences in Flower Color among Gentiana lutea Populations.

    Science.gov (United States)

    Sobral, Mar; Veiga, Tania; Domínguez, Paula; Guitián, Javier A; Guitián, Pablo; Guitián, José M

    2015-01-01

    Flower color variation among plant populations might reflect adaptation to local conditions such as the interacting animal community. In the northwest Iberian Peninsula, flower color of Gentiana lutea varies longitudinally among populations, ranging from orange to yellow. We explored whether flower color is locally adapted and the role of pollinators and seed predators as agents of selection by analyzing the influence of flower color on (i) pollinator visitation rate and (ii) escape from seed predation and (iii) by testing whether differences in pollinator communities correlate with flower color variation across populations. Finally, (iv) we investigated whether variation in selective pressures explains flower color variation among 12 G. lutea populations. Flower color influenced pollinator visits and differences in flower color among populations were related to variation in pollinator communities. Selective pressures on flower color vary among populations and explain part of flower color differences among populations of G. lutea. We conclude that flower color in G. lutea is locally adapted and that pollinators play a role in this adaptation.

  15. Selective Pressures Explain Differences in Flower Color among Gentiana lutea Populations.

    Directory of Open Access Journals (Sweden)

    Mar Sobral

    Full Text Available Flower color variation among plant populations might reflect adaptation to local conditions such as the interacting animal community. In the northwest Iberian Peninsula, flower color of Gentiana lutea varies longitudinally among populations, ranging from orange to yellow. We explored whether flower color is locally adapted and the role of pollinators and seed predators as agents of selection by analyzing the influence of flower color on (i pollinator visitation rate and (ii escape from seed predation and (iii by testing whether differences in pollinator communities correlate with flower color variation across populations. Finally, (iv we investigated whether variation in selective pressures explains flower color variation among 12 G. lutea populations. Flower color influenced pollinator visits and differences in flower color among populations were related to variation in pollinator communities. Selective pressures on flower color vary among populations and explain part of flower color differences among populations of G. lutea. We conclude that flower color in G. lutea is locally adapted and that pollinators play a role in this adaptation.

  16. A case-mix classification system for explaining healthcare costs using administrative data in Italy.

    Science.gov (United States)

    Corti, Maria Chiara; Avossa, Francesco; Schievano, Elena; Gallina, Pietro; Ferroni, Eliana; Alba, Natalia; Dotto, Matilde; Basso, Cristina; Netti, Silvia Tiozzo; Fedeli, Ugo; Mantoan, Domenico

    2018-03-04

    The Italian National Health Service (NHS) provides universal coverage to all citizens, granting primary and hospital care with a copayment system for outpatient and drug services. Financing of Local Health Trusts (LHTs) is based on a capitation system adjusted only for age, gender and area of residence. We applied a risk-adjustment system (Johns Hopkins Adjusted Clinical Groups System, ACG® System) in order to explain health care costs using routinely collected administrative data in the Veneto Region (North-eastern Italy). All residents in the Veneto Region were included in the study. The ACG system was applied to classify the regional population based on the following information sources for the year 2015: Hospital Discharges, Emergency Room visits, Chronic disease registry for copayment exemptions, ambulatory visits, medications, the Home care database, and drug prescriptions. Simple linear regressions were used to contrast an age-gender model to models incorporating more comprehensive risk measures aimed at predicting health care costs. A simple age-gender model explained only 8% of the variance of 2015 total costs. Adding diagnoses-related variables provided a 23% increase, while pharmacy based variables provided an additional 17% increase in explained variance. The adjusted R-squared of the comprehensive model was 6 times that of the simple age-gender model. ACG System provides substantial improvement in predicting health care costs when compared to simple age-gender adjustments. Aging itself is not the main determinant of the increase of health care costs, which is better explained by the accumulation of chronic conditions and the resulting multimorbidity. Copyright © 2018. Published by Elsevier B.V.

  17. What Is Sexual Orientation All About? Explaining an Evolutionary Paradox

    OpenAIRE

    Brad Bowins

    2015-01-01

    Numerous psychological, biological, and evolutionary theories have been proposed to explain sexual orientation. For a theory to be valid it must account for the evolutionary or Darwinian paradox of how homosexual behavior seemingly blocking evolutionary fitness could have evolved. Typically it is only evolutionary based theories that attempt to address this issue. All theories proposed to date have limitations, a major one being that they tend to be specific for male or female sexual orientat...

  18. Discovering and explaining work-family strategies of parents in Luxembourg

    OpenAIRE

    Zhelyazkova, Nevena

    2014-01-01

    The presented analysis discovers and explains typical patterns of work-family reconciliation for parents who had a child in the same period (2003) and in the same country (Luxembourg), thus facing the same macroeconomic and institutional conditions. Work-family trajectories are reconstructed as sequences of states using administrative records, so that working hours and use of leave provisions or other social security benefits are taken into account. Next, a clustering algorithm is applied to ...

  19. Glacial ocean circulation and stratification explained by reduced atmospheric temperature

    OpenAIRE

    Jansen, Malte F.

    2016-01-01

    To understand climatic swings between glacial and interglacial climates we need to explain the observed fluctuations in atmospheric carbon dioxide (CO2), which in turn are most likely driven by changes in the deep ocean circulation. This study presents a model for differences in the deep ocean circulation between glacial and interglacial climates consistent with both our physical understanding and various proxy observations. The results suggest that observed changes in ocean circulation and s...

  20. Effect of calcified plaques on estimation of arterial stenosis of lower extremity in diabetic foot patients using multislice computed tomography angiography

    International Nuclear Information System (INIS)

    Yu Xiaojing; Jin Yan; Wang Ge; Li Chunzhi; Zhang Yi; Ren Hua

    2013-01-01

    Objective: To investigate the impacts of calcified plaques on estimation of arterial stenosis of lower extremity in diabetic foot patients using 16 -slice computed tomography angiography (MSCTA). Materials and Methods: Thirty-five patients (representing 38 cases)underwent both MSCTA and digital subtraction angiography (DSA) examinations. The arteries of lower extremity were divided into 15 anatomic segments, and the degree of artery stenosis in each segment was classified as normal, mildly, moderately. severely or occluded. The extent of calcification in each segment was also assessed on cross -sectional image of MDCTA and was classified as absent, mildly, moderately, or severely. Using DSA as the standard reference, the sensitivity, specificity, accuracy, Youden index, positive predictive value and negative predictive value of MSCTA were calculated. Agreement between MSCTA and DSA was assessed by Cohen's kappa statistics. Results: In the noncalcified, mildly and moderately calcified segments of the artery above the knee, for the detection of segments that had more than mild stenosis, the sensitivity, specificity, accuracy. Youden index, positive predictive value and negative predictive value of MSCTA were 97.1%, 98.7%, 98.2%, 95.8%, 97.0% and 98.7%, respectively. In the severely calcified segments of the artery above the knee, for the detection of segments that had more than mild stenosis, the sensitivity, specificity, accuracy, Youden index, positive predictive value and negative predictive value of MSCTA were 96.3%, 93.8%, 94.7%, 90.1%, 89.7% and 97.8%, respectively. In the noncalcified, mildly and moderately calcified segments of the artery below the knee, for the detection of segments that had more than mild stenosis, the sensitivity, specificity, accuracy, Youden index, positive predictive value and negative predictive value of MSCTA were 95.1%, 93.2%, 94.1%, 88.3%, 93.4% and 94.9%, respectively. In the severely calcified segments of the artery below the

  1. Do the SuperKamiokande atmospheric neutrino results explain electric charge quantisation?

    International Nuclear Information System (INIS)

    Foot, R.; Volkas, R.R.

    1998-08-01

    It is shown that the SuperKamiokande atmospheric neutrino results explain electric charge quantisation, provided that the oscillation mode is ν μ → ν τ and that the neutrino mass is of the Majorana type. It is emphasised that neutrino oscillation and neutrinoless double beta decay experiments provide important information regarding the seemingly unrelated issue of electric charge quantisation

  2. Beyond dichotomous explanations: Explaining constitutional control of the executieve with fuzzy-sets.

    NARCIS (Netherlands)

    Pennings, P.J.M.

    2003-01-01

    What are the main variations in the constitutional control of the executive in 45 parliamentary democracies and how can these differences be accounted for? Four competing hypotheses, based on dichotomies, explain the degree of this control by means of contrasting institutional settings: consensus

  3. Beyond dichotomous explanations: explaining constitutional control of the executive with fuzzy-sets

    NARCIS (Netherlands)

    Pennings, P.J.M.

    2003-01-01

    What are the main variations in the constitutional control of the executive in 45 parliamentary democracies and how can these differences be accounted for? Four competing hypotheses, based on dichotomies, explain the degree of this control by means of contrasting institutional settings: consensus

  4. Depressive status explains a significant amount of the variance in COPD assessment test (CAT) scores.

    Science.gov (United States)

    Miravitlles, Marc; Molina, Jesús; Quintano, José Antonio; Campuzano, Anna; Pérez, Joselín; Roncero, Carlos

    2018-01-01

    COPD assessment test (CAT) is a short, easy-to-complete health status tool that has been incorporated into the multidimensional assessment of COPD in order to guide therapy; therefore, it is important to understand the factors determining CAT scores. This is a post hoc analysis of a cross-sectional, observational study conducted in respiratory medicine departments and primary care centers in Spain with the aim of identifying the factors determining CAT scores, focusing particularly on the cognitive status measured by the Mini-Mental State Examination (MMSE) and levels of depression measured by the short Beck Depression Inventory (BDI). A total of 684 COPD patients were analyzed; 84.1% were men, the mean age of patients was 68.7 years, and the mean forced expiratory volume in 1 second (%) was 55.1%. Mean CAT score was 21.8. CAT scores correlated with the MMSE score (Pearson's coefficient r =-0.371) and the BDI ( r =0.620), both p CAT scores and explained 45% of the variability. However, a model including only MMSE and BDI scores explained up to 40% and BDI alone explained 38% of the CAT variance. CAT scores are associated with clinical variables of severity of COPD. However, cognitive status and, in particular, the level of depression explain a larger percentage of the variance in the CAT scores than the usual COPD clinical severity variables.

  5. Explaining the Higgs decays at the LHC with an extended electroweak model

    International Nuclear Information System (INIS)

    Alves, Alexandre; Ramirez Barreto, E.; Dias, A.G.; Pires, S.C.A. de; Rodrigues da Silva, P.S.; Queiroz, Farinaldo S.

    2013-01-01

    We show that the observed enhancement in the diphoton decays of the recently discovered new boson at the LHC, which we assume to be a Higgs boson, can be naturally explained by a new doublet of charged vector bosons from extended electroweak models with SU(3) C x SU(3) L x U(1) X symmetry. These models are also rather economical in explaining the measured signal strengths, within the current experimental errors, demanding fewer assumptions and less parameters tuning. Our results show a good agreement between the theoretical expected sensitivity to a 126-125 GeV Higgs boson, and the experimental significance observed in the diphoton channel at the 8 TeV LHC. Effects of an invisible decay channel for the Higgs boson are also taken into account, in order to anticipate a possible confirmation of deficits in the branching ratios into ZZ * , WW * , bottom quarks, and tau leptons. (orig.)

  6. Mutations in the VEGFR3 signaling pathway explain 36% of familial lymphedema

    DEFF Research Database (Denmark)

    Mendola, A; Schlögel, M J; Ghalamkarpour, A

    2013-01-01

    Lymphedema is caused by dysfunction of lymphatic vessels, leading to disabling swelling that occurs mostly on the extremities. Lymphedema can be either primary (congenital) or secondary (acquired). Familial primary lymphedema commonly segregates in an autosomal dominant or recessive manner. It can...... of these putative genes. We screened 78 index patients from families with inherited lymphedema for mutations in FLT4, GJC2, FOXC2, SOX18, GATA2, CCBE1, and PTPN14. Altogether, we discovered 28 mutations explaining 36% of the cases. Additionally, 149 patients with sporadic primary lymphedema were screened for FLT4......, FOXC2, SOX18, CCBE1, and PTPN14. Twelve mutations were found that explain 8% of the cases. Still unidentified is the genetic cause of primary lymphedema in 64% of patients with a family history and 92% of sporadic cases. Identification of those genes is important for understanding of etiopathogenesis...

  7. The variance of the locally measured Hubble parameter explained with different estimators

    DEFF Research Database (Denmark)

    Odderskov, Io Sandberg Hess; Hannestad, Steen; Brandbyge, Jacob

    2017-01-01

    We study the expected variance of measurements of the Hubble constant, H0, as calculated in either linear perturbation theory or using non-linear velocity power spectra derived from N-body simulations. We compare the variance with that obtained by carrying out mock observations in the N......-body simulations, and show that the estimator typically used for the local Hubble constant in studies based on perturbation theory is different from the one used in studies based on N-body simulations. The latter gives larger weight to distant sources, which explains why studies based on N-body simulations tend...... to obtain a smaller variance than that found from studies based on the power spectrum. Although both approaches result in a variance too small to explain the discrepancy between the value of H0 from CMB measurements and the value measured in the local universe, these considerations are important in light...

  8. Explaining the diversity of motivations behind community renewable energy

    International Nuclear Information System (INIS)

    Bauwens, Thomas

    2016-01-01

    Community-based renewable energy initiatives may be important actors in the transition toward low-carbon energy systems. In turn, stimulating investments in renewable energy production at the community level requires a better understanding of investors' motives. This paper aims to study the heterogeneity of motivations that drive individuals to participate in community renewable energy projects and the underlying explanatory factors behind this, as well as the implications for their level of engagement in initiatives. Based on quantitative data from an original survey conducted with two renewable energy cooperatives in Flanders, the statistical analysis shows that cooperative members should not be considered as one homogeneous group. Several categories of members with different motives and levels of engagement can be distinguished. This heterogeneity is explained by contrasts in terms of institutional settings, spatial patterns and attitudes to the diffusion of institutional innovations. Regarding policy implications, the findings suggest that this heterogeneity should be taken into account in designing more effective supporting policies to stimulate investments at the community level. The activation of social norms is also shown to be a promising mechanism for triggering investment decisions, although the implications of its interplay with economic incentives should be further explored. - Highlights: •Community-based energy projects are important actors in the low-carbon transition. •The diversity of motivations and level of engagement among members is analysed. •Several segments of members with different characteristics are distinguished. •Institutional, spatial and innovation diffusion dimensions explain this diversity. •This heterogeneity among investors should be taken into account in policy-making.

  9. Reinforcement Learning Explains Conditional Cooperation and Its Moody Cousin.

    Directory of Open Access Journals (Sweden)

    Takahiro Ezaki

    2016-07-01

    Full Text Available Direct reciprocity, or repeated interaction, is a main mechanism to sustain cooperation under social dilemmas involving two individuals. For larger groups and networks, which are probably more relevant to understanding and engineering our society, experiments employing repeated multiplayer social dilemma games have suggested that humans often show conditional cooperation behavior and its moody variant. Mechanisms underlying these behaviors largely remain unclear. Here we provide a proximate account for this behavior by showing that individuals adopting a type of reinforcement learning, called aspiration learning, phenomenologically behave as conditional cooperator. By definition, individuals are satisfied if and only if the obtained payoff is larger than a fixed aspiration level. They reinforce actions that have resulted in satisfactory outcomes and anti-reinforce those yielding unsatisfactory outcomes. The results obtained in the present study are general in that they explain extant experimental results obtained for both so-called moody and non-moody conditional cooperation, prisoner's dilemma and public goods games, and well-mixed groups and networks. Different from the previous theory, individuals are assumed to have no access to information about what other individuals are doing such that they cannot explicitly use conditional cooperation rules. In this sense, myopic aspiration learning in which the unconditional propensity of cooperation is modulated in every discrete time step explains conditional behavior of humans. Aspiration learners showing (moody conditional cooperation obeyed a noisy GRIM-like strategy. This is different from the Pavlov, a reinforcement learning strategy promoting mutual cooperation in two-player situations.

  10. Use of focus groups in explaining environmental risks

    International Nuclear Information System (INIS)

    Wong, J.W.

    1994-01-01

    Risk assessors need to remember their job is to determine risks which are then balanced against the cost of remediation. Since the ultimate customer is the public, they must be an integral part of both key risk assessment as well as remediation decisions. Focus groups offer a cost effective means to open-quotes get a feelclose quotes for what publics want and don't want. This paper is a kit for using focus groups to test and translate into common language, the risk assessor's ideas and methods. Explaining Monte Carlo methods for a simple aspect of ecological risk assessment is included as an example along with practical tips and a list of what the public equates to risk as they perceive it

  11. Explaining NDVI trends in northern Burkina Faso

    DEFF Research Database (Denmark)

    Rasmussen, Kjeld; Fensholt, Rasmus; Fog, Bjarne

    2014-01-01

    by a distinct spatial pattern and strongly dominated by negative trends in Normalized Difference Vegetation Index (NDVI). The aim of the paper is to explain this distinct pattern. When studied over the period 2000–2012, using NDVI data from the MODIS sensor the spatial pattern of NDVI trends indicates that non......-climatic factors are involved. By relating NDVI trends to landscape elements and land use change we demonstrate that NDVI trends in the north-western parts of the study area are mostly related to landscape elements, while this is not the case in the south-eastern parts, where rapidly changing land use, including....... expansion of irrigation, plays a major role. It is inferred that a process of increased redistribution of fine soil material, water and vegetation from plateaus and slopes to valleys, possibly related to higher grazing pressure, may provide an explanation of the observed pattern of NDVI trends. Further work...

  12. Explaining mutualism variation: a new evolutionary paradox?

    Science.gov (United States)

    Heath, Katy D; Stinchcombe, John R

    2014-02-01

    The paradox of mutualism is typically framed as the persistence of interspecific cooperation, despite the potential advantages of cheating. Thus, mutualism research has tended to focus on stabilizing mechanisms that prevent the invasion of low-quality partners. These mechanisms alone cannot explain the persistence of variation for partner quality observed in nature, leaving a large gap in our understanding of how mutualisms evolve. Studying partner quality variation is necessary for applying genetically explicit models to predict evolution in natural populations, a necessary step for understanding the origins of mutualisms as well as their ongoing dynamics. An evolutionary genetic approach, which is focused on naturally occurring mutualist variation, can potentially synthesize the currently disconnected fields of mutualism evolution and coevolutionary genetics. We outline explanations for the maintenance of genetic variation for mutualism and suggest approaches necessary to address them. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  13. Ireland and immigration: explaining the absence of the far right

    OpenAIRE

    Garner, Steve

    2007-01-01

    This article seeks to explain the absence of far-right political formations in the history of the Republic of Ireland, especially in relation to immigration. I argue that the ‘mainstream’ nationalist parties have implemented a racialized governance of Ireland via the issue of citizenship (in the referendum of 2004). While hegemonic ideas on the racial purity of indigenous populations and the highly ambivalent attitudes and policies on immigration pursued over the last decade are characteristi...

  14. Dynamic optimal foraging theory explains vertical migrations of bigeye tuna

    DEFF Research Database (Denmark)

    Thygesen, Uffe Høgsbro; Sommer, Lene; Evans, Karen

    2016-01-01

    Bigeye tuna are known for remarkable daytime vertical migrations between deep water, where food is abundant but the water is cold, and the surface, where water is warm but food is relatively scarce. Here we investigate if these dive patterns can be explained by dynamic optimal foraging theory...... behaves such as to maximize its energy gains. The model therefore provides insight into the processes underlying observed behavioral patterns and allows generating predictions of foraging behavior in unobserved environments...

  15. Social cognitive theories used to explain physical activity behavior in adolescents: a systematic review and meta-analysis.

    Science.gov (United States)

    Plotnikoff, Ronald C; Costigan, Sarah A; Karunamuni, Nandini; Lubans, David R

    2013-05-01

    To systematically review and examine the explanatory power of key social-cognitive theories used to explain physical activity (PA) intention and behavior, among adolescents. A systematic review and meta-analysis of the literature was performed using the electronic databases Medline, Cumulative Index to Nursing and Allied Health Literature, SPORTdiscus, EBSCO and Education Resources Information Center, Proquest Education Journals Collection, Science Direct, Web of Science and Scopus for social-cognitive theories (i.e., Health Promotion Model, Theory of Planned Behavior, Theory of Reasoned Action, Protection Motivation Theory, Social Cognitive Theory/Self-Efficacy Theory, Health Belief Model, Self-Determination Theory, Transtheoretical Model) used to explain PA intention and behavior. Related keywords in titles, abstracts, or indexing fields were searched. Twenty-three studies satisfied the inclusion criteria and were retained for data extraction and analysis; 16 were cross-sectional studies and seven were longitudinal studies. Most studies employed self-report measures. In general, the models explained greater proportions of variance for intention compared to behavior. The meta-analyses revealed 33% and 48% of the variance respectively for PA and intention were explained by social cognitive models. Few studies have tested the predictive capacity of social cognitive theories to explain objectively measured PA. The majority of PA variance remains unexplained and more theoretical research is needed. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. Assessing the impact of autonomous motivation and psychological need satisfaction in explaining adherence to an exercise referral scheme.

    Science.gov (United States)

    Eynon, Michael John; O'Donnell, Christopher; Williams, Lynn

    2017-10-01

    Given the mixed findings concerning self-determination theory in explaining adherence to exercise referral schemes (ERS), the present study attempted to examine whether autonomous motivation and psychological need satisfaction could predict ERS adherence. Participants referred to an 8-week ERS completed self-report measures grounded in self-determination theory and basic needs theory at baseline (N = 124), mid-scheme (N = 58), and at the end of the scheme (N = 40). Logistic regressions were used to analyse the data. Autonomous motivation measured at mid-scheme explained between 12 and 16% of the variance in ERS adherence. Autonomy, relatedness and competence measured at mid-scheme explained between 18 and 26% of the variance in ERS adherence. This model also explained between 18 and 25% when measured at the end of the scheme. The study found limited evidence for the role of autonomous motivation in explaining ERS adherence. Stronger support was found for the satisfaction of the three needs for autonomy, relatedness and competence in predicting ERS adherence. Future research should tap into the satisfaction of all three needs collectively to help foster ERS adherence.

  17. Automatically explaining machine learning prediction results: a demonstration on type 2 diabetes risk prediction.

    Science.gov (United States)

    Luo, Gang

    2016-01-01

    Predictive modeling is a key component of solutions to many healthcare problems. Among all predictive modeling approaches, machine learning methods often achieve the highest prediction accuracy, but suffer from a long-standing open problem precluding their widespread use in healthcare. Most machine learning models give no explanation for their prediction results, whereas interpretability is essential for a predictive model to be adopted in typical healthcare settings. This paper presents the first complete method for automatically explaining results for any machine learning predictive model without degrading accuracy. We did a computer coding implementation of the method. Using the electronic medical record data set from the Practice Fusion diabetes classification competition containing patient records from all 50 states in the United States, we demonstrated the method on predicting type 2 diabetes diagnosis within the next year. For the champion machine learning model of the competition, our method explained prediction results for 87.4 % of patients who were correctly predicted by the model to have type 2 diabetes diagnosis within the next year. Our demonstration showed the feasibility of automatically explaining results for any machine learning predictive model without degrading accuracy.

  18. The use of Rich and Suter diagrams to explain the electron configurations of transition elements

    Energy Technology Data Exchange (ETDEWEB)

    Orofino, Hugo; Machado, Sergio P.; Faria, Roberto B., E-mail: faria@iq.ufrj.br [Instituto de Quimica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil)

    2013-09-01

    Rich and Suter diagrams are a very useful tool to explain the electron configurations of all transition elements, and in particular, the s{sup 1} and s{sup 0} configurations of the elements Cr, Cu, Nb, Mo, Ru, Rh, Pd, Ag, and Pt. The application of these diagrams to the inner transition elements also explains the electron configurations of lanthanoids and actinoids, except for Ce, Pa, U, Np, and Cm, whose electron configurations are indeed very special because they are a mixture of several configurations. (author)

  19. The use of Rich and Suter diagrams to explain the electron configurations of transition elements

    Directory of Open Access Journals (Sweden)

    Hugo Orofino

    2013-01-01

    Full Text Available Rich and Suter diagrams are a very useful tool to explain the electron configurations of all transition elements, and in particular, the s¹ and s0 configurations of the elements Cr, Cu, Nb, Mo, Ru, Rh, Pd, Ag, and Pt. The application of these diagrams to the inner transition elements also explains the electron configurations of lanthanoids and actinoids, except for Ce, Pa, U, Np, and Cm, whose electron configurations are indeed very special because they are a mixture of several configurations.

  20. Explaining Helping Behavior in a Cooperative Learning Classroom Setting Using Attribution Theory

    Science.gov (United States)

    Ahles, Paula M.; Contento, Jann M.

    2006-01-01

    This recently completed study examined whether attribution theory can explain helping behavior in an interdependent classroom environment that utilized a cooperative-learning model. The study focused on student participants enrolled in 6 community college communication classes taught by the same instructor. Three levels of cooperative-learning…

  1. Explaining the power-law distribution of human mobility through transportation modality decomposition

    Science.gov (United States)

    Zhao, Kai; Musolesi, Mirco; Hui, Pan; Rao, Weixiong; Tarkoma, Sasu

    2015-03-01

    Human mobility has been empirically observed to exhibit Lévy flight characteristics and behaviour with power-law distributed jump size. The fundamental mechanisms behind this behaviour has not yet been fully explained. In this paper, we propose to explain the Lévy walk behaviour observed in human mobility patterns by decomposing them into different classes according to the different transportation modes, such as Walk/Run, Bike, Train/Subway or Car/Taxi/Bus. Our analysis is based on two real-life GPS datasets containing approximately 10 and 20 million GPS samples with transportation mode information. We show that human mobility can be modelled as a mixture of different transportation modes, and that these single movement patterns can be approximated by a lognormal distribution rather than a power-law distribution. Then, we demonstrate that the mixture of the decomposed lognormal flight distributions associated with each modality is a power-law distribution, providing an explanation to the emergence of Lévy Walk patterns that characterize human mobility patterns.

  2. Does religiosity explain economic outcomes? Understanding religiosity is crucial to informed policy making

    Czech Academy of Sciences Publication Activity Database

    Popova, Olga

    (2017), č. článku 335. E-ISSN 2054-9571 Institutional support: RVO:67985998 Keywords : religiosity * economic outcomes Subject RIV: AH - Economics https://wol.iza.org/articles/does-religiosity-explain-economic-outcomes/long

  3. ROLE OF PARENTS' ADJUSTMENT IN EXPLAINING PERCEPTION OF ADOLESCENTS' NEGATIVE INTERACTIONS WITH MOTHER AND FATHER

    Directory of Open Access Journals (Sweden)

    Tamara Efendić-Spahić

    2014-04-01

    Full Text Available The research was conducted with the aim of examining the contribution of facets of the adjustment of mother and father for explaining the adolescents’ perception of negative relations with parents. The following adjustment measures were used in this research: anxiety, hypersensitivity, inner coherence, interpersonal orientation and aggression of mother and father individually. The measures of negative interactions between adolescents and parents are conceptualized through the dimension of negative relations with parents, which includes adolescents’ assessment regarding the rejection by father and mother and the assessment of negative relations with father and mother. The research was conducted on a sample including 273 subjects in total: 47 female subjects, 44 male subjects and their parents. For testing the hypotheses, the multiple regression analysis was used. The obtained results show that adjustment facets are important predictors for explaining the perception of negative relations with father. The facet of aggression stands as the most significant predictor among adjustment factors for the group of fathers. For the group of mothers, adjustment did not prove a significant predictor for explaining perception of negative relations. Possible explanations for a modest contribution of mother’s adjustment can be found in the possibility for the quality of family interactions with mother is more explained by an emotional relation that is established between her and the child in early childhood and does not change its quality at later development stages.

  4. Value Chain Envy: Explaining New Entry and Vertical Integration in Popular Music

    NARCIS (Netherlands)

    Mol, J.M.; Wijnberg, N.M.; Carroll, C.

    2005-01-01

    The concepts of value creation, value capture, and value protection are employed to explain new entry and vertical integration. It is posited that if, at one stage of the value system, the share of value captured is disproportionally higher than the share of value created, value chain envy will

  5. Value chain envy : Explaining new entry and vertical integration in popular music

    NARCIS (Netherlands)

    Mol, J.M.; Wijnberg, N.M.; Carroll, C.

    The concepts of value creation, value capture, and value protection are employed to explain new entry and vertical integration. It is posited that if, at one stage of the value system, the share of value captured is disproportionally higher than the share of value created, value chain envy will

  6. The Sensitization Model to Explain How Chronic Pain Exists Without Tissue Damage

    NARCIS (Netherlands)

    van Wilgen, C. Paul; Keizer, Doeke

    The interaction of nurses with chronic pain patients is often difficult. One of the reasons is that chronic pain is difficult to explain, because no obvious anatomic defect or tissue damage is present. There is now enough evidence available indicating that chronic pain syndromes such as low back

  7. Will Not Want: Self-Control Rather than Motivation Explains the Female Advantage in Report Card Grades

    Science.gov (United States)

    Duckworth, Angela L.; Shulman, Elizabeth P.; Mastronarde, Andrew J.; Patrick, Sarah D.; Zhang, Jinghui; Druckman, Jeremy

    2015-01-01

    Girls earn better grades than boys, but the mechanism explaining this gender difference is not well understood. We examined the relative importance of self-control and motivation in explaining the female advantage in grades. In Study 1, we surveyed middle school teachers and found they judged girls to be higher in both school motivation and self-control. In Studies 2 and 3—using self-reported motivation and teacher- and/or parent-reported self-control, and quarterly and final grades obtained from school records—we find that self-control, but not school motivation, helps to explain the gender gap in academic performance. In these studies, girls appeared to be more self-controlled than boys, but—contrary to teacher judgments in Study 1—did not appear to be more motivated to do well in school. PMID:25883522

  8. Climate and terrain factors explaining streamflow response and recession in Australian catchments

    Directory of Open Access Journals (Sweden)

    A. I. J. M. van Dijk

    2010-01-01

    Full Text Available Daily streamflow data were analysed to assess which climate and terrain factors best explain streamflow response in 183 Australian catchments. Assessed descriptors of catchment response included the parameters of fitted baseflow models, and baseflow index (BFI, average quick flow and average baseflow derived by baseflow separation. The variation in response between catchments was compared with indicators of catchment climate, morphology, geology, soils and land use. Spatial coherence in the residual unexplained variation was investigated using semi-variogram techniques. A linear reservoir model (one parameter; recession coefficient produced baseflow estimates as good as those obtained using a non-linear reservoir (two parameters and for practical purposes was therefore considered an appropriate balance between simplicity and explanatory performance. About a third (27–34% of the spatial variation in recession coefficients and BFI was explained by catchment climate indicators, with another 53% of variation being spatially correlated over distances of 100–150 km, probably indicative of substrate characteristics not captured by the available soil and geology data. The shortest recession half-times occurred in the driest catchments and were attributed to intermittent occurrence of fast-draining (possibly perched groundwater. Most (70–84% of the variation in average baseflow and quick flow was explained by rainfall and climate characteristics; another 20% of variation was spatially correlated over distances of 300–700 km, possibly reflecting a combination of terrain and climate factors. It is concluded that catchment streamflow response can be predicted quite well on the basis of catchment climate alone. The prediction of baseflow recession response should be improved further if relevant substrate properties were identified and measured.

  9. Explaining Consumer Safe Food Handling Through Behavior-Change Theories: A Systematic Review.

    Science.gov (United States)

    Young, Ian; Reimer, Danielle; Greig, Judy; Meldrum, Richard; Turgeon, Patricia; Waddell, Lisa

    2017-11-01

    Consumers often engage in unsafe food handling behaviors at home. Previous studies have investigated the ability of behavior-change theories to explain and predict these behaviors. The purpose of this review was to determine which theories are most consistently associated with consumers' safe food handling behaviors across the published literature. A standardized systematic review methodology was used, consisting of the following steps: comprehensive search strategy; relevance screening of identified references; confirmation of relevance and characterization of relevant articles; risk-of-bias assessment; data extraction; and descriptive analysis of study results. A total of 20 relevant studies were identified; they were mostly conducted in Australia (40%) and the United States (35%) and used a cross-sectional design (65%). Most studies targeted young adults (65%), and none focused on high-risk consumer groups. The outcomes of 70% of studies received high overall risk-of-bias ratings, largely due to a lack of control for confounding variables. The most commonly applied theory was the Theory of Planned Behavior (45% of studies), which, along with other investigated theories of behavior change, was frequently associated with consumer safe food handling behavioral intentions and behaviors. However, overall, there was wide variation in the specific constructs found to be significantly associated and in the percentage of variance explained in each outcome across studies. The results suggest that multiple theories of behavior change can help to explain consumer safe food handling behaviors and could be adopted to guide the development of future behavior-change interventions. In these contexts, theories should be appropriately selected and adapted to meet the needs of the specific target population and context of interest.

  10. A theory with consolidation: Linking everything to explain everything

    Science.gov (United States)

    Biraris, Gaurav Shantaram

    The paper reports a theory which gives explicit (ontic) understanding of the abstract (epistemic) mechanisms spanning many branches of physics. It results to most modern physics starting from Newtonian physics by abandoning progress in twentieth century. The theory assumes consolidation of points in 4-balls of specific radius in the universe. Thus the 4-balls are fundamental elements of the universe. Analogue of momentum defined as soul vector is assumed to be induced on the 4-balls at the beginning of the universe. Then with progression of local time, collisions happen leading to different rotations of CNs. For such rotations, the consolidation provides centripetal binding. By using general terminologies of force and work, the mass energy mechanism gets revealed. The theory provides explicit interpretation of intrinsic properties of mass, electric charge, color charge, weak charge, spin etc. It also provides explicit understanding of the wave-particle duality & quantum mechanics. Epistemic study of the universe with the consolidation results to conventional quantum theories. Elementary mechanism of the field interactions is evident due to conservation of the soul vectors, and its epistemic expectation results to the gauge theories. The theory predicts that four types of interaction would exist in the universe along with the acceptable relative strengths; it provides fundamental interpretation of the physical forces. Further, it explains the basic mechanisms which can be identified with dark energy & dark matter. It also results to (or explains) entanglement, chirality, excess of matter, 4-component spinor, real-abstract (ontic-epistemic) correspondence etc. The theory is beyond standard model and results to the standard model, relativity, dark energy & dark matter, starting by simple assumptions.

  11. Strange history: the fall of Rome explained in Hereditas.

    Science.gov (United States)

    Bengtsson, Bengt O

    2014-12-01

    In 1921 Hereditas published an article on the fall of Rome written by the famous classical scholar Martin P:son Nilsson. Why was a paper on this unexpected topic printed in the newly founded journal? To Nilsson, the demise of the Roman Empire was explained by the "bastardization" occurring between "races" from different parts of the realm. Offspring from mixed couples were of a less stable "type" than their parents, due to the breaking up by recombination of the original hereditary dispositions, which led to a general loss of competence to rule and govern. Thus, the "hardness" of human genes, together with their recombination, was - according to Nilsson - the main cause of the fall of Rome. Nilsson's argument is not particularly convincingly presented. Human "races" are taken to have the same genetic structure as inbred crop strains, and Nilsson believes in a metaphysical unity between the individual and the race to which it belongs. However, in my view, Martin P:son Nilsson and his friend Herman Nilsson-Ehle had wider aims with the article than to explain a historical event. The article can be read as indicating strong support from the classical human sciences to the ambitious new science of genetics. Support is also transferred from genetics to the conservative worldview, where the immutability and inflexibility of the Mendelian genes are used to strengthen the wish for greater stability in politics and life. The strange article in Hereditas can, thus, be read as an early instance in the - still ongoing - tug-of-war between the conservative and the liberal ideological poles over how genetic results best are socially interpreted. © 2015 The Authors.

  12. Social processes explaining the benefits of Al-Anon participation.

    Science.gov (United States)

    Timko, Christine; Halvorson, Max; Kong, Calvin; Moos, Rudolf H

    2015-12-01

    This study examined social processes of support, goal direction, provision of role models, and involvement in rewarding activities to explain benefits of participating in Al-Anon, a 12-step mutual-help program for people concerned about another person's substance use. Newcomers to Al-Anon were studied at baseline and 6 months later, at which time they were identified as having either sustained attendance or dropped out. Among both newcomers and established Al-Anon members ("old-timers"), we also used number of Al-Anon meetings attended during follow-up to indicate extent of participation. Social processes significantly mediated newcomers' sustained attendance status versus dropped out and outcomes of Al-Anon in the areas of life context (e.g., better quality of life, better able to handle problems due to the drinker), improved positive symptoms (e.g., higher self-esteem, more hopeful), and decreased negative symptoms (e.g., less abuse, less depressed). Social processes also significantly mediated newcomers' number of meetings attended and outcomes. However, among old-timers, Al-Anon attendance was not associated with outcomes, so the potential mediating role of social processes could not be examined, but social processes were associated with outcomes. Findings add to the growing body of work identifying mechanisms by which 12-step groups are effective, by showing that bonding, goal direction, and access to peers in recovery and rewarding pursuits help to explain associations between sustained Al-Anon participation among newcomers and improvements on key concerns of Al-Anon attendees. Al-Anon is free of charge and widely available, making it a potentially cost-effective public health resource for help alleviating negative consequences of concern about another's addiction. (c) 2016 APA, all rights reserved).

  13. String theory: A brand new theory that claims to explain everything in existence

    International Nuclear Information System (INIS)

    Pal, P.B.

    1988-01-01

    Background of the origin of the string theories which have shown possibilities of unifying all four basic forces including gravity is described and the concepts behind these theories are explained for the layman. (M.G.R.)

  14. Explaining Racial Disparities in Child Asthma Readmission Using a Causal Inference Approach.

    Science.gov (United States)

    Beck, Andrew F; Huang, Bin; Auger, Katherine A; Ryan, Patrick H; Chen, Chen; Kahn, Robert S

    2016-07-01

    Childhood asthma is characterized by disparities in the experience of morbidity, including the risk for readmission to the hospital after an initial hospitalization. African American children have been shown to have more than 2 times the hazard of readmission when compared with their white counterparts. To explain why African American children are at greater risk for asthma-related readmissions than white children. This study was completed as part of the Greater Cincinnati Asthma Risks Study, a population-based, prospective, observational cohort. From August 2010 to October 2011, it enrolled 695 children, aged 1 to 16 years, admitted for asthma or wheezing who identified as African American (n = 441) or white (n = 254) in an inpatient setting of an urban, tertiary care children's hospital. The main outcome was time to asthma-related readmission and race was the predictor. Biologic, environmental, disease management, access, and socioeconomic hardship variables were measured; their roles in understanding racial readmission disparities were conceptualized using a directed acyclic graphic. Inverse probability of treatment weighting balanced African American and white children with respect to key measured variables. Racial differences in readmission hazard were assessed using weighted Cox proportional hazards regression and Kaplan-Meier curves. The sample was 65% male (n = 450), and the median age was 5.4 years. African American children were 2.26 times more likely to be readmitted than white children (95% CI, 1.56-3.26). African American children significantly differed with respect to nearly every measured biologic, environmental, disease management, access, and socioeconomic hardship variable. Socioeconomic hardship variables explained 53% of the observed disparity (hazard ratio, 1.47; 95% CI, 1.05-2.05). The addition of biologic, environmental, disease management, and access variables resulted in 80% of the readmission disparity being explained. The

  15. A third alternative to explain recent observations: Future deceleration

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Subenoy, E-mail: schakraborty@math.jdvu.ac.in; Pan, Supriya, E-mail: span@research.jdvu.ac.in; Saha, Subhajit, E-mail: subhajit1729@gmail.com

    2014-11-10

    In the present work we discuss a third alternative to explain the latest observational data concerning the accelerating Universe and its different stages. The particle creation mechanism in the framework of non-equilibrium thermodynamics is considered as a basic cosmic mechanism acting on the flat FRW geometry. By assuming that the gravitationally induced particle production occurs under “adiabatic” conditions, the deceleration parameter is expressed in terms of the particle creation rate which is chosen as a truncated power series of the Hubble parameter. The model shows the evolution of the Universe starting from inflation to the present late time acceleration and it also predicts future decelerating stage.

  16. A third alternative to explain recent observations: Future deceleration

    Science.gov (United States)

    Chakraborty, Subenoy; Pan, Supriya; Saha, Subhajit

    2014-11-01

    In the present work we discuss a third alternative to explain the latest observational data concerning the accelerating Universe and its different stages. The particle creation mechanism in the framework of non-equilibrium thermodynamics is considered as a basic cosmic mechanism acting on the flat FRW geometry. By assuming that the gravitationally induced particle production occurs under "adiabatic" conditions, the deceleration parameter is expressed in terms of the particle creation rate which is chosen as a truncated power series of the Hubble parameter. The model shows the evolution of the Universe starting from inflation to the present late time acceleration and it also predicts future decelerating stage.

  17. Learning Argumentation Skills through the Use of Prompts for Self-Explaining Examples

    Science.gov (United States)

    Schworm, Silke; Renkl, Alexander

    2007-01-01

    Learning with self-explaining examples is an effective method in well-structured domains. The authors analyzed this method in teaching the complex skill of argumentation, experimentally comparing 4 conditions (N = 71 student teachers) that differed with respect to whether and how the processing of the examples was supported by self-explanation…

  18. Can clade age alone explain the relationship between body size and diversity?

    NARCIS (Netherlands)

    Etienne, Rampal S.; de Visser, Sara N.; Janzen, Thijs; Olsen, Jeanine L.; Olff, Han; Rosindell, James

    2012-01-01

    One of the most striking patterns observed among animals is that smaller-bodied taxa are generally much more diverse than larger-bodied taxa. This observation seems to be explained by the mere fact that smaller-bodied taxa tend to have an older evolutionary origin and have therefore had more time to

  19. Variation in fistula use across dialysis facilities: is it explained by case-mix?

    Science.gov (United States)

    Tangri, Navdeep; Moorthi, Ranjani; Tighiouhart, Hocine; Meyer, Klemens B; Miskulin, Dana C

    2010-02-01

    Arteriovenous fistulas (AVFs) remain the preferred vascular access for hemodialysis patients. Dialysis facilities that fail to meet Centers for Medicare & Medicaid Services goals cite patient case-mix as a reason for low AVF prevalence. This study aimed to determine the magnitude of the variability in AVF usage across dialysis facilities and the extent to which patient case-mix explains it. The vascular access used in 10,112 patients dialyzed at 173 Dialysis Clinic Inc. facilities from October 1 to December 31, 2004, was evaluated. The access in use was considered to be an AVF if it was used for >70% of hemodialysis treatments. Mixed-effects models with a random intercept for dialysis facilities evaluated the effect of facilities on AVF usage. Sequentially adjusted multivariate models measured the extent to which patient factors (case-mix) explain variation across facilities in AVF rates. 3787 patients (38%) were dialyzed using AVFs. There was a significant facility effect: 7.6% of variation in AVF use was attributable to facility. This was reduced to 7.1% after case-mix adjustment. There were no identified specific facility-level factors that explained the interfacility variation. AVF usage varies across dialysis facilities, and patient case-mix did not reduce this variation. In this study, 92% of the total variation in AVF usage was due to patient factors, but most were not measurable. A combination of patient factors and process indicators should be considered in adjudicating facility performance for this quality indicator.

  20. Data to support "Boosted Regression Tree Models to Explain Watershed Nutrient Concentrations & Biological Condition"

    Data.gov (United States)

    U.S. Environmental Protection Agency — Spreadsheets are included here to support the manuscript "Boosted Regression Tree Models to Explain Watershed Nutrient Concentrations and Biological Condition". This...

  1. Symbiodinium mitigate the combined effects of hypoxia and acidification on a noncalcifying cnidarian

    KAUST Repository

    Klein, Shannon G.; Pitt, Kylie A.; Nitschke, Matthew R.; Goyen, Samantha; Welsh, David T.; Suggett, David J.; Carroll, Anthony R.

    2017-01-01

    polyps of a model host jellyfish (Cassiopea sp.) under reduced O (~2.09 mg/L) and pH (~ 7.63) scenarios in a full-factorial experiment. Host fitness was characterized as asexual reproduction and their ability to regulate internal pH and Symbiodinium

  2. Explaining the Gap in Charter and Traditional Public School Teacher Turnover Rates

    Science.gov (United States)

    Stuit, David A.; Smith, Thomas M.

    2012-01-01

    This study uses national survey data to examine why charter school teachers are more likely to turnover than their traditional public school counterparts. We test whether the turnover gap is explained by different distributions of factors that are empirically and theoretically linked to turnover risk. We find that the turnover rate of charter…

  3. Development of an equine groove model to induce metacarpophalangeal osteoarthritis: a pilot study on 6 horses.

    Science.gov (United States)

    Maninchedda, Ugo; Lepage, Olivier M; Gangl, Monika; Hilairet, Sandrine; Remandet, Bernard; Meot, Francoise; Penarier, Geraldine; Segard, Emilie; Cortez, Pierre; Jorgensen, Christian; Steinberg, Régis

    2015-01-01

    The aim of this work was to develop an equine metacarpophalangeal joint model that induces osteoarthritis that is not primarily mediated by instability or inflammation. The study involved six Standardbred horses. Standardized cartilage surface damage or "grooves" were created arthroscopically on the distal dorsal aspect of the lateral and medial metacarpal condyles of a randomly chosen limb. The contralateral limb was sham operated. After 2 weeks of stall rest, horses were trotted 30 minutes every other day for 8 weeks, then evaluated for lameness and radiographed. Synovial fluid was analyzed for cytology and biomarkers. At 10 weeks post-surgery, horses were euthanized for macroscopic and histologic joint evaluation. Arthroscopic grooving allowed precise and identical damage to the cartilage of all animals. Under the controlled exercise regime, this osteoarthritis groove model displayed significant radiographic, macroscopic, and microscopic degenerative and reactive changes. Histology demonstrated consistent surgically induced grooves limited to non-calcified cartilage and accompanied by secondary adjacent cartilage lesions, chondrocyte necrosis, chondrocyte clusters, cartilage matrix softening, fissuring, mild subchondral bone inflammation, edema, and osteoblastic margination. Synovial fluid biochemistry and cytology demonstrated significantly elevated total protein without an increase in prostaglandin E2, neutrophils, or chondrocytes. This equine metacarpophalangeal groove model demonstrated that standardized non-calcified cartilage damage accompanied by exercise triggered altered osteochondral morphology and cartilage degeneration with minimal or inefficient repair and little inflammatory response. This model, if validated, would allow for assessment of disease processes and the effects of therapy.

  4. Impact of glucose intolerance on coronary calcified lesions evaluated using multislice computed tomography

    International Nuclear Information System (INIS)

    Nomura, Kyoko; Ohwaki, Kazuhiro; Yano, Eiji; Yamanouchi, Toshikazu; Kim, Gwang U.

    2007-01-01

    Metabolic syndrome has the unique concept that the common occurrence of individual disease components increases the risk of coronary artery disease (CAD). However, some studies suggest that the burden of different CAD risk factors is not equal, and focusing on the whole set of risk factors might neglect the impact of individual factors that could be useful targets for prophylactic therapies. The purpose of this study was to investigate the effect of glucose intolerance on CAD using multislice computed tomography (MSCT). Ninety-eight consecutive patients with at least one traditional CAD risk factor who visited a municipal hospital were enrolled in this study. The risk factors were impaired glucose tolerance (fasting glucose≥110 mg/dl or patients with diabetes), low high-density lipoprotein cholesterol (HDL-C, 25 kg/m 2 for men and >23 kg/m 2 for women). CAD was determined by the presence of either stenoses, non-calcified plaques or calcified lesions. The following risk factors were significantly related in univariate logistic models: glucose intolerance and coronary calcified lesions (p=0.001), and hypertriglycemia and non-calcified plaque lesions (p=0.048). Multivariate models showed that glucose intolerance was significantly associated with calcified lesions, even after adjustment for gender, age, low HDL-C, hypertriglycemia, hypertension, and obesity (p=0.018). Our results suggest that glucose intolerance might be closely related to the presence of coronary calcified lesions among traditional CAD risk factors. (author)

  5. The significance of circumscribed malignant mammographic masses in the surveillance of BRCA 1/2 gene mutation carriers

    International Nuclear Information System (INIS)

    Kaas, R.; Kroger, R.; Besnard, A.P.E.; Koops, W.; Pameijer, F.A.; Prevoo, W.; Loo, C.E.; Muller, S.H.; Hendriks, J.H.C.L.

    2004-01-01

    Breast cancers in gene mutation carriers may escape mammographic detection because of rapid growth and tumor expansion. Therefore, they may mimic benign lesions on the mammogram. Twenty-nine BRCA 1/2 mutation carriers under surveillance developed 31 breast cancers between 1994 and 2001 at a mean age of 44.2 years. Controls were 63 women with 67 breast cancers in the same period at a mean age of 53.8 years, also under surveillance because of a life time risk of at least 15%. In 26% of the carriers vs. 48% of the controls, mammography was the method that first suspected a malignancy. Seven radiologists performed a retrospective review of the original mammograms to establish technical assessment, with special attention for circumscribed lesions and estimated probability of malignancy. In the mutation carriers seven (23%) circumscribed non-calcified mammographic masses were found and three in the controls (4.5%) P=0.01. These masses were proven to be malignant. In both groups around 70% of these fast-growing circumscribed lesions were detected by the patients. The masses were situated in breasts with a good interpretable breast pattern. BRCA 1/2 mutation carriers had a significantly higher percentage of circumscribed non-calcified mammographic masses that proved to be malignant. These mammographic lesions in women at high risk should be described as at least Birads 0 and worked-up with ultrasound and needle biopsy. (orig.)

  6. Development of an equine groove model to induce metacarpophalangeal osteoarthritis: a pilot study on 6 horses.

    Directory of Open Access Journals (Sweden)

    Ugo Maninchedda

    Full Text Available The aim of this work was to develop an equine metacarpophalangeal joint model that induces osteoarthritis that is not primarily mediated by instability or inflammation. The study involved six Standardbred horses. Standardized cartilage surface damage or "grooves" were created arthroscopically on the distal dorsal aspect of the lateral and medial metacarpal condyles of a randomly chosen limb. The contralateral limb was sham operated. After 2 weeks of stall rest, horses were trotted 30 minutes every other day for 8 weeks, then evaluated for lameness and radiographed. Synovial fluid was analyzed for cytology and biomarkers. At 10 weeks post-surgery, horses were euthanized for macroscopic and histologic joint evaluation. Arthroscopic grooving allowed precise and identical damage to the cartilage of all animals. Under the controlled exercise regime, this osteoarthritis groove model displayed significant radiographic, macroscopic, and microscopic degenerative and reactive changes. Histology demonstrated consistent surgically induced grooves limited to non-calcified cartilage and accompanied by secondary adjacent cartilage lesions, chondrocyte necrosis, chondrocyte clusters, cartilage matrix softening, fissuring, mild subchondral bone inflammation, edema, and osteoblastic margination. Synovial fluid biochemistry and cytology demonstrated significantly elevated total protein without an increase in prostaglandin E2, neutrophils, or chondrocytes. This equine metacarpophalangeal groove model demonstrated that standardized non-calcified cartilage damage accompanied by exercise triggered altered osteochondral morphology and cartilage degeneration with minimal or inefficient repair and little inflammatory response. This model, if validated, would allow for assessment of disease processes and the effects of therapy.

  7. Effects of Hyperthyroidism on Coronary Artery Disease: A Computed Tomography Angiography Study.

    Science.gov (United States)

    Beyer, Christoph; Plank, Fabian; Friedrich, Guy; Wildauer, Matthias; Feuchtner, Gudrun

    2017-10-01

    Changes in thyroid hormone concentration can negatively affect the cardiovascular system. Subclinical hyperthyroidism has been linked to an increase of cardiovascular heart disease, however, clinical effects and significance are still uncertain. Therefore, we analyzed coronary computed tomography angiographies of patients with overt and subclinical hyperthyroidism for quantitative parameters and plaque morphology. Seven hundred forty-four (47.1% female) patients who underwent coronary computed tomography angiography were stratified into 3 groups: 51 patients with overt, 74 patients with subclinical hyperthyroidism, and 619 patients with euthyroidism. Analysis included grades of stenosis (no stenosis = 0, mild 70%) and plaque types (noncalcified, mixed, and calcified), segment involvement score (SIS), noncalcified SIS, and high-risk plaque features (napkin ring sign, low attenuation plaque, spotty calcifications, positive remodelling). Patients with overt and subclinical hyperthyroidism had more high-grade stenoses (39.2% vs 37.8% vs 24.2%; P = 0.007) and a higher coronary calcium score (456.5 vs 199.5 vs 155.9; P hyperthyroidism, followed by those with subclinical hyperthyroidism, had the most high-risk plaque features: napkin ring (21.6% vs 9.5% vs 6.0%, P hyperthyroid patients. Patients with subclinical and overt hyperthyroidism showed more high-grade coronary stenoses, plaque burden, and high-risk plaque features than patients with euthyroidism, which indicates that an increase of thyroid hormones might lead to coronary vascular degeneration and plaque instability. Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  8. Characteristics of broadband slow earthquakes explained by a Brownian model

    Science.gov (United States)

    Ide, S.; Takeo, A.

    2017-12-01

    Brownian slow earthquake (BSE) model (Ide, 2008; 2010) is a stochastic model for the temporal change of seismic moment release by slow earthquakes, which can be considered as a broadband phenomena including tectonic tremors, low frequency earthquakes, and very low frequency (VLF) earthquakes in the seismological frequency range, and slow slip events in geodetic range. Although the concept of broadband slow earthquake may not have been widely accepted, most of recent observations are consistent with this concept. Then, we review the characteristics of slow earthquakes and how they are explained by BSE model. In BSE model, the characteristic size of slow earthquake source is represented by a random variable, changed by a Gaussian fluctuation added at every time step. The model also includes a time constant, which divides the model behavior into short- and long-time regimes. In nature, the time constant corresponds to the spatial limit of tremor/SSE zone. In the long-time regime, the seismic moment rate is constant, which explains the moment-duration scaling law (Ide et al., 2007). For a shorter duration, the moment rate increases with size, as often observed for VLF earthquakes (Ide et al., 2008). The ratio between seismic energy and seismic moment is constant, as shown in Japan, Cascadia, and Mexico (Maury et al., 2017). The moment rate spectrum has a section of -1 slope, limited by two frequencies corresponding to the above time constant and the time increment of the stochastic process. Such broadband spectra have been observed for slow earthquakes near the trench axis (Kaneko et al., 2017). This spectrum also explains why we can obtain VLF signals by stacking broadband seismograms relative to tremor occurrence (e.g., Takeo et al., 2010; Ide and Yabe, 2014). The fluctuation in BSE model can be non-Gaussian, as far as the variance is finite, as supported by the central limit theorem. Recent observations suggest that tremors and LFEs are spatially characteristic

  9. Dark matter "transporting" mechanism explaining positron excesses

    Science.gov (United States)

    Kim, Doojin; Park, Jong-Chul; Shin, Seodong

    2018-04-01

    We propose a novel mechanism to explain the positron excesses, which are observed by satellite-based telescopes including PAMELA and AMS-02, in dark matter (DM) scenarios. The novelty behind the proposal is that it makes direct use of DM around the Galactic Center where DM populates most densely, allowing us to avoid tensions from cosmological and astrophysical measurements. The key ingredients of this mechanism include DM annihilation into unstable states with a very long laboratory-frame life time and their "retarded" decay near the Earth to electron-positron pair(s) possibly with other (in)visible particles. We argue that this sort of explanation is not in conflict with relevant constraints from big bang nucleosynthesis and cosmic microwave background. Regarding the resultant positron spectrum, we provide a generalized source term in the associated diffusion equation, which can be readily applicable to any type of two-"stage" DM scenarios wherein production of Standard Model particles occurs at completely different places from those of DM annihilation. We then conduct a data analysis with the recent AMS-02 data to validate our proposal.

  10. Do sex differences in rumination explain sex differences in depression?

    Science.gov (United States)

    Shors, Tracey J; Millon, Emma M; Chang, Han Yan M; Olson, Ryan L; Alderman, Brandon L

    2017-01-02

    It is generally accepted that women tend to ruminate more than men do and these thought patterns are often associated with depressive symptoms (Nolen-Hoeksema et al., ). Based on these findings, we considered whether the relationship between rumination and depression is stronger in women than in men and if so, whether this might explain the higher prevalence of major depressive disorder (MDD) in women and finally, whether the association can be disrupted through a mind/body intervention. Adult men and women, most of whom were clinically depressed, participated in an intervention known as MAP Training, which combines "mental" training with silent meditation and "physical" training with aerobic exercise (Shors et al., ). After eight weeks of training, both men and women reported significantly fewer symptoms of depression and fewer ruminative thoughts (Alderman et al., ). Statistical correlations between depressive symptoms and ruminative thoughts were strong and significant (rho > 0.50; p depressive symptoms relate to "reflective" ruminations, which involve analyses of past events, feelings, and behaviors. This is also the only relationship that dissipated after the intervention. In general, these analyses suggest that the strength of the relationship between depressive symptoms and rumination does not necessarily explain sex differences in depression; but because the relationship is strong, targeting rumination through intervention can reduce the incidence of MDD, which is more prevalent among women. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  11. Evidence-Based Identification of Key Beliefs Explaining Infant Male Circumcision Motivation Among Expectant Parents in Zimbabwe: Targets for Behavior Change Messaging.

    Science.gov (United States)

    Montaño, Daniel E; Tshimanga, Mufuta; Hamilton, Deven T; Gorn, Gerald; Kasprzyk, Danuta

    2018-02-01

    Slow adult male circumcision uptake is one factor leading some to recommend increased priority for infant male circumcision (IMC) in sub-Saharan African countries. This research, guided by the integrated behavioral model (IBM), was carried out to identify key beliefs that best explain Zimbabwean parents' motivation to have their infant sons circumcised. A quantitative survey, designed from qualitative elicitation study results, was administered to independent representative samples of 800 expectant mothers and 795 expectant fathers in two urban and two rural areas in Zimbabwe. Multiple regression analyses found IMC motivation among fathers was explained by instrumental attitude, descriptive norm and self-efficacy; while motivation among mothers was explained by instrumental attitude, injunctive norm, descriptive norm, self-efficacy, and perceived control. Regression analyses of beliefs underlying IBM constructs found some overlap but many differences in key beliefs explaining IMC motivation among mothers and fathers. We found differences in key beliefs among urban and rural parents. Urban fathers' IMC motivation was explained best by behavioral beliefs, while rural fathers' motivation was explained by both behavioral and efficacy beliefs. Urban mothers' IMC motivation was explained primarily by behavioral and normative beliefs, while rural mothers' motivation was explained mostly by behavioral beliefs. The key beliefs we identified should serve as targets for developing messages to improve demand and maximize parent uptake as IMC programs are rolled out. These targets need to be different among urban and rural expectant mothers and fathers.

  12. Immediate survival focus: synthesizing life history theory and dual process models to explain substance use.

    Science.gov (United States)

    Richardson, George B; Hardesty, Patrick

    2012-01-01

    Researchers have recently applied evolutionary life history theory to the understanding of behaviors often conceived of as prosocial or antisocial. In addition, researchers have applied cognitive science to the understanding of substance use and used dual process models, where explicit cognitive processes are modeled as relatively distinct from implicit cognitive processes, to explain and predict substance use behaviors. In this paper we synthesized these two theoretical perspectives to produce an adaptive and cognitive framework for explaining substance use. We contend that this framework provides new insights into the nature of substance use that may be valuable for both clinicians and researchers.

  13. Explaining parents' school involvement : The role of ethnicity and gender in the Netherlands

    NARCIS (Netherlands)

    Fleischmann, Fenella; de Haas, Annabel

    2016-01-01

    Ethnic minority parents are often less involved with their children's schooling, and this may hamper their children's academic success, thus contributing to ethnic educational inequality. The authors aim to explain differences in parental involvement, using nationally representative survey data from

  14. Vectorlike chiral fourth family to explain muon anomalies

    Science.gov (United States)

    Raby, Stuart; Trautner, Andreas

    2018-05-01

    The Standard Model (SM) is amended by one generation of quarks and leptons which are vectorlike (VL) under the SM gauge group but chiral with respect to a new U(1 ) 3 -4 gauge symmetry. We show that this model can simultaneously explain the deviation of the muon g -2 as well as the observed anomalies in b →s μ+μ- transitions without conflicting with the data on Higgs decays, lepton flavor violation, or Bs-B¯s mixing. The model is string theory motivated and Grand Unified Theory compatible, i.e. UV complete, and fits the data predicting VL quarks, leptons, and a massive Z' at the TeV scale, as well as τ →3 μ and τ →μ γ within reach of future experiments. The Higgs couplings to SM generations are automatically aligned in flavor space.

  15. Factors explaining the level of voluntary human capital disclosure in the Brazilian capital market Factors explaining the level of voluntary human capital disclosure in the Brazilian capital market Factors explaining the level of voluntary human capital disclosure in the Brazilian capital market

    OpenAIRE

    Clea Beatriz Macagnan; Fernando Batista Fontana

    2013-01-01

    Purpose: This paper presents a study on factors explaining the level of voluntary human capital information in companies with shares in the Brazilian stock exchange. Assuming the existence of information asymmetry between managers and shareholders, agency theory states that disclosure might lead to a reduction in agency costs. The proprietary costs theory indicates that information disclosure might increase the company’s costs. According to these theories, the likelihood that the managers wil...

  16. A Model of How Different Biology Experts Explain Molecular and Cellular Mechanisms

    Science.gov (United States)

    Trujillo, Caleb M.; Anderson, Trevor R.; Pelaez, Nancy J.

    2015-01-01

    Constructing explanations is an essential skill for all science learners. The goal of this project was to model the key components of expert explanation of molecular and cellular mechanisms. As such, we asked: What is an appropriate model of the components of explanation used by biology experts to explain molecular and cellular mechanisms? Do…

  17. Can we explain the observed methane variability after the Mount Pinatubo eruption?

    NARCIS (Netherlands)

    Banda, Narcisa; Krol, M.; Van Weele, M.; Van Noije, T.; Le Sager, P.; Röckmann, T.

    2016-01-01

    The CH4 growth rate in the atmosphere showed large variations after the Pinatubo eruption in June 1991. A decrease of more than 10 ppb yr-1 in the growth rate over the course of 1992 was reported, and a partial recovery in the following year. Although several reasons have been proposed to explain

  18. Mapping information exposure on social media to explain differences in HPV vaccine coverage in the United States.

    Science.gov (United States)

    Dunn, Adam G; Surian, Didi; Leask, Julie; Dey, Aditi; Mandl, Kenneth D; Coiera, Enrico

    2017-05-25

    Together with access, acceptance of vaccines affects human papillomavirus (HPV) vaccine coverage, yet little is known about media's role. Our aim was to determine whether measures of information exposure derived from Twitter could be used to explain differences in coverage in the United States. We conducted an analysis of exposure to information about HPV vaccines on Twitter, derived from 273.8 million exposures to 258,418 tweets posted between 1 October 2013 and 30 October 2015. Tweets were classified by topic using machine learning methods. Proportional exposure to each topic was used to construct multivariable models for predicting state-level HPV vaccine coverage, and compared to multivariable models constructed using socioeconomic factors: poverty, education, and insurance. Outcome measures included correlations between coverage and the individual topics and socioeconomic factors; and differences in the predictive performance of the multivariable models. Topics corresponding to media controversies were most closely correlated with coverage (both positively and negatively); education and insurance were highest among socioeconomic indicators. Measures of information exposure explained 68% of the variance in one dose 2015 HPV vaccine coverage in females (males: 63%). In comparison, models based on socioeconomic factors explained 42% of the variance in females (males: 40%). Measures of information exposure derived from Twitter explained differences in coverage that were not explained by socioeconomic factors. Vaccine coverage was lower in states where safety concerns, misinformation, and conspiracies made up higher proportions of exposures, suggesting that negative representations of vaccines in the media may reflect or influence vaccine acceptance. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  19. Explaining Home Bias in Trade: The Role of Time Costs

    Directory of Open Access Journals (Sweden)

    Inkoo Lee

    2010-12-01

    Full Text Available We study how time costs, combined with elasticity of substitution across home and foreign goods, can explain the home bias puzzle in a framework of flexible prices. Using a simple two-country model, we show that introducing time costs to an otherwise standard competitive model improves its ability to rationalize home bias in trade. Our analysis suggests that home bias and corresponding incomplete risk-sharing naturally arise in the presence of time costs, even under the assumption of complete financial markets and low elasticity of substitution between home and foreign goods.

  20. A theory with consolidation: Linking everything to explain everything

    Directory of Open Access Journals (Sweden)

    Gaurav Shantaram Biraris

    Full Text Available The paper reports a theory which gives explicit (ontic understanding of the abstract (epistemic mechanisms spanning many branches of physics. It results to most modern physics starting from Newtonian physics by abandoning progress in twentieth century. The theory assumes consolidation of points in 4-balls of specific radius in the universe. Thus the 4-balls are fundamental elements of the universe. Analogue of momentum defined as soul vector is assumed to be induced on the 4-balls at the beginning of the universe. Then with progression of local time, collisions happen leading to different rotations of CNs. For such rotations, the consolidation provides centripetal binding. By using general terminologies of force and work, the mass energy mechanism gets revealed. The theory provides explicit interpretation of intrinsic properties of mass, electric charge, color charge, weak charge, spin etc. It also provides explicit understanding of the wave-particle duality & quantum mechanics. Epistemic study of the universe with the consolidation results to conventional quantum theories. Elementary mechanism of the field interactions is evident due to conservation of the soul vectors, and its epistemic expectation results to the gauge theories. The theory predicts that four types of interaction would exist in the universe along with the acceptable relative strengths; it provides fundamental interpretation of the physical forces. Further, it explains the basic mechanisms which can be identified with dark energy & dark matter. It also results to (or explains entanglement, chirality, excess of matter, 4-component spinor, real-abstract (ontic-epistemic correspondence etc. The theory is beyond standard model and results to the standard model, relativity, dark energy & dark matter, starting by simple assumptions. Keywords: Beyond standard model, Phenomenology, Relativity, Dark matter, Realist theory

  1. Multi-step inhibition explains HIV-1 protease inhibitor pharmacodynamics and resistance

    Science.gov (United States)

    Rabi, S. Alireza; Laird, Gregory M.; Durand, Christine M.; Laskey, Sarah; Shan, Liang; Bailey, Justin R.; Chioma, Stanley; Moore, Richard D.; Siliciano, Robert F.

    2013-01-01

    HIV-1 protease inhibitors (PIs) are among the most effective antiretroviral drugs. They are characterized by highly cooperative dose-response curves that are not explained by current pharmacodynamic theory. An unresolved problem affecting the clinical use of PIs is that patients who fail PI-containing regimens often have virus that lacks protease mutations, in apparent violation of fundamental evolutionary theory. Here, we show that these unresolved issues can be explained through analysis of the effects of PIs on distinct steps in the viral life cycle. We found that PIs do not affect virion release from infected cells but block entry, reverse transcription, and post–reverse transcription steps. The overall dose-response curves could be reconstructed by combining the curves for each step using the Bliss independence principle, showing that independent inhibition of multiple distinct steps in the life cycle generates the highly cooperative dose-response curves that make these drugs uniquely effective. Approximately half of the inhibitory potential of PIs is manifest at the entry step, likely reflecting interactions between the uncleaved Gag and the cytoplasmic tail (CT) of the Env protein. Sequence changes in the CT alone, which are ignored in current clinical tests for PI resistance, conferred PI resistance, providing an explanation for PI failure without resistance. PMID:23979165

  2. Interest organizations across economic sectors : explaining interest group density in the European Union

    NARCIS (Netherlands)

    Berkhout, Joost; Carroll, Brendan J.; Braun, Caelesta; Chalmers, Adam W.; Destrooper, Tine; Lowery, David; Otjes, Simon; Rasmussen, Anne

    2015-01-01

    The number of interest organizations (density) varies across policy domains, political issues and economic sectors. This shapes the nature and outcomes of interest representation. In this contribution, we explain the density of interest organizations per economic sector in the European Union on the

  3. Interest organizations across economic sectors: explaining interest group density in the European Union

    NARCIS (Netherlands)

    Berkhout, Joost; Carroll, Brendan; Braun, Caelesta; Chalmers, Adam; De Strooper, Tine; Lowery, David; Otjes, Simon; Rasmussen, Anne

    2015-01-01

    The number of interest organizations (density) varies across policy domains, political issues and economic sectors. This shapes the nature and outcomes of interest representation. In this contribution, we explain the density of interest organizations per economic sector in the European Union on the

  4. Computed tomography in the diagnosis of Addison's disease

    International Nuclear Information System (INIS)

    Yamauchi, Teiyu; Yashiro, Naofumi; Iio, Masahiro

    1985-01-01

    The computed tomography (CT) findings of the adrenal glands were described in six patients with Addison's disease. Three of four patients due to tuberculosis showed calcification in bilateral adrenal glands. In all three, non-calcified portions of left adrenal glands were identified by CT. One showed bilaterally enlarged adrenal glands. Bilateral adrenal glands were small in a patient with idiopatic Addison's disease. One patient of metastatic infiltration of the adrenal glands showed nodular masses in bilateral adrenal beds. CT findings were useful to clarify the etiology of Addison's patients. (author)

  5. Sonographic demonstration of a gallstone ileus

    International Nuclear Information System (INIS)

    Uebel, H.E.; Wilhelm, F.

    1987-01-01

    A woman of 60 years of age with acute abdominal pain, vomiting, constipation and radiological signs of small bowel obstruction was subjected to sonographic examination. Careful examination of the entire abdomen demonstrated a hyperechoic object within the distended terminal ileum with an intensive acoustic shadow. The gallbladder was not visible. This strongly suggested gallstone ileus, especially since the patient had a history of gallbladder disease. She was treated immediately by enterotomy and extraction of a noncalcified obstructing stone. The value of ultrasound in detecting gallstones causing small bowel obstruction is discussed. (orig.) [de

  6. Sonographic demonstration of a gallstone ileus

    Energy Technology Data Exchange (ETDEWEB)

    Uebel, H.E.; Wilhelm, F.

    1987-04-01

    A woman of 60 years of age with acute abdominal pain, vomiting, constipation and radiological signs of small bowel obstruction was subjected to sonographic examination. Careful examination of the entire abdomen demonstrated a hyperechoic object within the distended terminal ileum with an intensive acoustic shadow. The gallbladder was not visible. This strongly suggested gallstone ileus, especially since the patient had a history of gallbladder disease. She was treated immediately by enterotomy and extraction of a noncalcified obstructing stone. The value of ultrasound in detecting gallstones causing small bowel obstruction is discussed.

  7. Can variation in risk of nest predation explain altitudinal migration in tropical birds?

    Science.gov (United States)

    Boyle, W Alice

    2008-03-01

    Migration is among the best studied of animal behaviors, yet few empirical studies have tested hypotheses explaining the ultimate causes of these cyclical annual movements. Fretwell's (1980) hypothesis predicts that if nest predation explains why many tropical birds migrate uphill to breed, then predation risk must be negatively associated with elevation. Data from 385 artificial nests spanning 2,740 m of elevation on the Atlantic slope of Costa Rica show an overall decline in predation with increasing elevation. However, nest predation risk was highest at intermediate elevations (500-650 m), not at lowest elevations. The proportion of nests depredated by different types of predators differed among elevations. These results imply that over half of the altitudinal migrant bird species in this region migrate to safer breeding areas than their non-breeding areas, suggesting that variation in nest predation risk could be an important benefit of uphill migrations of many species.

  8. How Can We Explain Poverty? Case Study of Dee Reveals the Complexities

    Science.gov (United States)

    Seccombe, Karen

    2011-01-01

    Many theories have been offered to explain why people are impoverished. This article by Karen Seccombe uses the case study of "Dee," a newly single mother, to explore four of the most common: individualism, social structuralism, the culture of poverty, and fatalism. She concludes that poverty is a highly complex phenomenon, and it is likely that…

  9. Explaining the Increase in Publication Productivity among Academic Staff: A Generational Perspective

    Science.gov (United States)

    Kyvik, Svein; Aksnes, Dag W.

    2015-01-01

    In Norwegian research universities, a large individual increase has taken place in scientific and scholarly publishing over the last 30 years. The purpose of this article is to explain the reasons for this growth in a generational perspective. We put forward six hypotheses that can be illuminated by cross-sectional data drawn from five surveys to…

  10. Establishing a Set of Macroeconomic Factors Explaining Variation Over Time of Performance in Business Sectors

    Directory of Open Access Journals (Sweden)

    Audrius Dzikevičius

    2016-06-01

    Full Text Available With increasing competitiveness of companies and business sectors in the domestic markets of Lithuania, economic units are frequently confronted with the lack of methods for more detailed analysis of external factors explaining the variation over time of corporate financial indicators. The analysis or forecasting of financial indicators is usually linked with the development of a stock market or undertaken to estimate the probability of bankruptcy. However, there is a lack of studies aimed at identifying links between macroeconomic factors and financial performance indicators and explaining their variation over time. To serve that purpose, the factors of the macroeconomic environment that are most significant for certain economic activities have been identified and analysed to enable explaining the variation over time patterns of corporate financial indicators. The analysis covers economic performance, i.e. financial performance indicators and their links with macroeconomic factors, in 89 business sectors of Lithuania at a three-digit level of NACE 2 ed. The findings of the research indicate that the unemployment level in the country, the volume of export and import and the GDP are the most important macroeconomic factors that can be used to forecast different profitability, financial leverage, liquidity and other financial performance indicators of individual business sectors or companies. The research has not unfolded any significant differences between business sectors therefore the above factors are considered generic macroeconomic factors enabling to explain financial performance indicators of the 89 business sectors. Hence, special attention has to be paid to identifying and analysing specific factors and assessing the causal link. When established, the set of such factors provides a framework for building of a model to forecast business sector financial indicators.

  11. Potential impact of increased temperature and CO2 on particulate dimethylsulfoniopropionate in the Southeastern Bering Sea

    Directory of Open Access Journals (Sweden)

    Peter A. Lee

    2011-06-01

    Full Text Available The potential impact of elevated sea surface temperature (SST and pCO2 on algal community structure and particulate dimethylsulfoniopropionate (DMSPp concentrations in the southeastern Bering Sea was examined using a shipboard “Ecostat” continuous culture system. The ecostat system was used to mimic the conditions projected to exist in the world's oceans by the end of this century (i.e. elevated pCO2 (750 ppm and elevated SST (ambient + 4°C. Two experiments were conducted using natural phytoplankton assemblages from the high-nutrient low-chlorophyll (HNLC central basin and from the middle domain of the southeastern continental shelf. At the HNLC site, the relative abundances of haptophytes and pelagophytes were higher and the relative abundance of diatoms lower under “greenhouse” conditions (i.e. combined 750 ppm CO2 and elevated temperature than control conditions (380 ppm CO2 and ambient temperature. This shift in algal community structure was accompanied by increases in DMSPp (2–3 fold, DMSPp:Chl a (2–3 fold and DMSP:PON (2 fold. At the continental shelf site, the changes in the relative abundances of haptophytes, pelagophytes and diatoms under “greenhouse” conditions were similar to those observed at the HNLC site, with 2.5 fold increases in DMSPp, 50–100% increases in DMSPp:Chl a and 1.8 fold increases in DMSP:PON. At both locations, changes in community structure and the DMSPp parameters were largely driven by increasing temperature. The observed changes were also consistent with the phytoplankton-DMS-albedo climate feedback mechanism proposed in the Charlson-Lovelock-Andreae-Warren (CLAW hypothesis.

  12. Important variables in explaining real-time peak price in the independent power market of Ontario

    International Nuclear Information System (INIS)

    Rueda, I.E.A.; Marathe, A.

    2005-01-01

    This paper uses support vector machines (SVM) based learning algorithm to select important variables that help explain the real-time peak electricity price in the Ontario market. The Ontario market was opened to competition only in May 2002. Due to the limited number of observations available, finding a set of variables that can explain the independent power market of Ontario (IMO) real-time peak price is a significant challenge for the traders and analysts. The kernel regressions of the explanatory variables on the IMO real-time average peak price show that non-linear dependencies exist between the explanatory variables and the IMO price. This non-linear relationship combined with the low variable-observation ratio rule out conventional statistical analysis. Hence, we use an alternative machine learning technique to find the important explanatory variables for the IMO real-time average peak price. SVM sensitivity analysis based results find that the IMO's predispatch average peak price, the actual import peak volume, the peak load of the Ontario market and the net available supply after accounting for load (energy excess) are some of the most important variables in explaining the real-time average peak price in the Ontario electricity market. (author)

  13. Using social cognitive theory to explain discretionary, "leisure-time" physical exercise among high school students.

    Science.gov (United States)

    Winters, Eric R; Petosa, Rick L; Charlton, Thomas E

    2003-06-01

    To examine whether knowledge of high school students' actions of self-regulation, and perceptions of self-efficacy to overcome exercise barriers, social situation, and outcome expectation will predict non-school related moderate and vigorous physical exercise. High school students enrolled in introductory Physical Education courses completed questionnaires that targeted selected Social Cognitive Theory variables. They also self-reported their typical "leisure-time" exercise participation using a standardized questionnaire. Bivariate correlation statistic and hierarchical regression were conducted on reports of moderate and vigorous exercise frequency. Each predictor variable was significantly associated with measures of moderate and vigorous exercise frequency. All predictor variables were significant in the final regression model used to explain vigorous exercise. After controlling for the effects of gender, the psychosocial variables explained 29% of variance in vigorous exercise frequency. Three of four predictor variables were significant in the final regression equation used to explain moderate exercise. The final regression equation accounted for 11% of variance in moderate exercise frequency. Professionals who attempt to increase the prevalence of physical exercise through educational methods should focus on the psychosocial variables utilized in this study.

  14. A Hierarchical Bayes Error Correction Model to Explain Dynamic Effects of Price Changes

    NARCIS (Netherlands)

    D. Fok (Dennis); R. Paap (Richard); C. Horváth (Csilla); Ph.H.B.F. Franses (Philip Hans)

    2005-01-01

    textabstractThe authors put forward a sales response model to explain the differences in immediate and dynamic effects of promotional prices and regular prices on sales. The model consists of a vector autoregression rewritten in error-correction format which allows to disentangle the immediate

  15. Explaining academic progress via combining concepts of integration theory and rational choice theory

    NARCIS (Netherlands)

    Beekhoven, S.; Jong, U. de; Hout, J.F.M.J. van

    2002-01-01

    In this article, elements of rational choice theory and integration theory are compared on the basis of their explanatory power to explain variance in academic progress. It is argued that both theoretical concepts could be combined. Furthermore the distinction between social and academic integration

  16. The Right Ventricle Explains Sex Differences in Survival in Idiopathic Pulmonary Arterial Hypertension

    NARCIS (Netherlands)

    Jacobs, W.; van de Veerdonk, M.C.; Trip, P.; de Man, F.S.; Heymans, M.W.; Marcus, J.T.; Kawut, S.M.; Bogaard, H.J.; Boonstra, A.; Vonk-Noordegraaf, A.

    2014-01-01

    Background: Male sex is an independent predictor of worse survival in pulmonary arterial hypertension (PAH). This finding might be explained by more severe pulmonary vascular disease, worse right ventricular (RV) function, or different response to therapy. The aim of this study was to investigate

  17. Sickness absence: could gender divide be explained by occupation, income, mental distress and health?

    Science.gov (United States)

    Smeby, Lisbeth; Bruusgaard, Dag; Claussen, Bjørgulf

    2009-09-01

    Women have more spells of sickness absence than men but the reasons for this are unknown. We wanted to see if occupation, working conditions, income, health and mental distress may explain this gender difference. In a health survey in 2000-01 of all Oslo inhabitants aged 40, 45, and 59/60 years, 11,072 (48.7%) participated. Survey data were linked to the National Insurance Administration and Statistics Norway for the 8,174 eligible for sickness pay in the next four years. Occupation, working conditions, general health and mental distress were self-reported, and income was from official statistics. Long-term sickness absence (>16 days) was calculated for 2001-04 as cumulative incidence and number of days reimbursed. Cumulative incidence was 50.1% for women and 34.7% for men in the four years after the survey. An age-adjusted female overweight of 48% was only reduced to 41% by adjusting for occupation, working conditions, income, self-reported health and mental distress. Duration of long-term sickness absence was 17 days more for women than for men, and was not influenced by adjustments. We have not explained why women have more sickness absence than men, either by work-related factors or by general health or mental distress. Factors explaining the gender divide should be sought elsewhere.

  18. An examination of multilevel factors that may explain gender differences in children's physical activity.

    Science.gov (United States)

    Crespo, Noe C; Corder, Kirsten; Marshall, Simon; Norman, Gregory J; Patrick, Kevin; Sallis, Jim F; Elder, John P

    2013-09-01

    Girls are less physically active than boys, yet no single study has examined the factors that may explain gender differences in children's physical activity (PA). This study was a cross-sectional analysis of data from 116 caregivers and their children aged 5-8 years who participated in the MOVE study. Caregivers reported various factors that may relate to children's PA (eg, encouragement for child PA and PA equipment at home). Child PA was measured by 7-day accelerometry. Linear regression tested for the variance in moderate-to-vigorous physical activity (MVPA) explained by gender and several variables. Gender and ethnicity interactions were examined. Caregivers were mostly female (97%), mean age 38 ± 6 years, mean BMI 28 ± 6 (kg/m2). Child's mean age was 8.1 ± 0.7, 54% were female and 40% were overweight/obese. Girls were less physically active than boys (54.1 ± 19.7 vs. 65.2 ± 28.0 daily minutes of MVPA, respectively). Among girls, more days of PE/week was associated with greater MVPA. Among boys, greater parent support for PA, greater parent modeling for PA, and greater number of PA equipment in the home were associated with greater MVPA. This study supports that boys and girls have different correlates for MVPA, which may partly explain gender differences in PA.

  19. Immediate Survival Focus: Synthesizing Life History Theory and Dual Process Models to Explain Substance Use

    Directory of Open Access Journals (Sweden)

    George B. Richardson

    2012-10-01

    Full Text Available Researchers have recently applied evolutionary life history theory to the understanding of behaviors often conceived of as prosocial or antisocial. In addition, researchers have applied cognitive science to the understanding of substance use and used dual process models, where explicit cognitive processes are modeled as relatively distinct from implicit cognitive processes, to explain and predict substance use behaviors. In this paper we synthesized these two theoretical perspectives to produce an adaptive and cognitive framework for explaining substance use. We contend that this framework provides new insights into the nature of substance use that may be valuable for both clinicians and researchers.

  20. Can molecular diffusion explain Space Shuttle plume spreading?

    Science.gov (United States)

    Meier, R. R.; Plane, John M. C.; Stevens, Michael H.; Paxton, L. J.; Christensen, A. B.; Crowley, G.

    2010-04-01

    The satellite-borne Global Ultraviolet Imager (GUVI) has produced more than 20 images of NASA Space Shuttle main engine plumes in the lower thermosphere. These reveal atomic hydrogen and, by inference, water vapor transport over hemispherical-scale distances with speeds much faster than expected from models of thermospheric wind motions. Furthermore, the hydrogen plumes expand rapidly. We find rates that exceed the horizontal diffusion speed at nominal plume altitudes of 104-112 km. Kelley et al. (2009) have proposed a 2-D turbulence mechanism to explain the observed spreading rates (and rapid advection) of the plumes. But upon further investigation, we conclude that H atom diffusion can indeed account for the observed expansion rates by recognizing that vertical diffusion quickly conveys atoms to higher altitudes where horizontal diffusion is much more rapid. We also find evidence for H atom production directly during the Shuttle's main engine burn.

  1. Can superhorizon cosmological perturbations explain the acceleration of the universe?

    International Nuclear Information System (INIS)

    Hirata, Christopher M.; Seljak, Uros

    2005-01-01

    We investigate the recent suggestions by Barausse et al. and Kolb et al. that the acceleration of the universe could be explained by large superhorizon fluctuations generated by inflation. We show that no acceleration can be produced by this mechanism. We begin by showing how the application of Raychaudhuri equation to inhomogeneous cosmologies results in several 'no go' theorems for accelerated expansion. Next we derive an exact solution for a specific case of initial perturbations, for which application of the Kolb et al. expressions leads to an acceleration, while the exact solution reveals that no acceleration is present. We show that the discrepancy can be traced to higher-order terms that were dropped in the Kolb et al. analysis. We proceed with the analysis of initial value formulation of general relativity to argue that causality severely limits what observable effects can be derived from superhorizon perturbations. By constructing a Riemann normal coordinate system on initial slice we show that no infrared divergence terms arise in this coordinate system. Thus any divergences found previously can be eliminated by a local rescaling of coordinates and are unobservable. We perform an explicit analysis of the variance of the deceleration parameter for the case of single-field inflation using usual coordinates and show that the infrared-divergent terms found by Barausse et al. and Kolb et al. cancel against several additional terms not considered in their analysis. Finally, we argue that introducing isocurvature perturbations does not alter our conclusion that the accelerating expansion of the universe cannot be explained by superhorizon modes

  2. Explaining Parents' School Involvement: The Role of Ethnicity and Gender in the Netherlands

    Science.gov (United States)

    Fleischmann, Fenella; de Haas, Annabel

    2016-01-01

    Ethnic minority parents are often less involved with their children's schooling, and this may hamper their children's academic success, thus contributing to ethnic educational inequality. The authors aim to explain differences in parental involvement, using nationally representative survey data from the Netherlands of parents of primary…

  3. Explaining slow economic growth and poor social development indicators: The case of Morocco

    NARCIS (Netherlands)

    S.I. Bergh (Sylvia)

    2005-01-01

    textabstractDrawing on elements of a political economy framework, this paper addresses two inter-related questions with regard to economic growth and public expenditure patterns in Morocco. The main factors that help explain Morocco’s relatively slow economic growth for the last few decades have to

  4. Explaining tourists satisfaction and intention to revisit Nha Trang, Viet Nam

    OpenAIRE

    Tran, Thi Ai Cam

    2011-01-01

    The first purpose of the thesis is to find how visitors evaluate the quality of different facets or attributes of a destination image of Nha Trang, how satisfied they are with Nha Trang, loyalty intention to revisit and willingness to recommend Nha Trang to others. The second is to investigate what “image” is most important to explain global satisfaction with visiting Nha Trang. The third is to investigate how perceived quality, satisfaction and other motivational or dismotivational factors ...

  5. Variations in body morphology explain sex differences in thermoeffector function during compensable heat stress.

    Science.gov (United States)

    Notley, Sean R; Park, Joonhee; Tagami, Kyoko; Ohnishi, Norikazu; Taylor, Nigel A S

    2017-05-01

    What is the central question of this study? Can sex-related differences in cutaneous vascular and sudomotor responses be explained primarily by variations in the ratio between body surface area and mass during compensable exercise that elicits equivalent heat-loss requirements and mean body temperature changes across participants? What is the main finding and its importance? Mass-specific surface area was a significant determinant of vasomotor and sudomotor responses in men and women, explaining 10-48% of the individual thermoeffector variance. Nonetheless, after accounting for changes in mean body temperature and morphological differences, sex explained only 5% of that inter-individual variability. It was concluded that sex differences in thermoeffector function are morphologically dependent, but not sex dependent. Sex is sometimes thought to be an independent modulator of cutaneous vasomotor and sudomotor function during heat exposure. Nevertheless, it was hypothesized that, when assessed during compensable exercise that evoked equal heat-loss requirements across participants, sex differences in those thermoeffectors would be explained by variations in the ratio between body surface area and mass (specific surface area). To evaluate that possibility, vasomotor and sudomotor functions were assessed in 60 individuals (36 men and 24 women) with widely varying (overlapping) specific surface areas (range, 232.3-292.7 and 241.2-303.1 cm 2  kg -1 , respectively). Subjects completed two trials in compensable conditions (28°C, 36% relative humidity) involving rest (20 min) and steady-state cycling (45 min) at fixed, area-specific metabolic heat-production rates (light, ∼135 W m -2 ; moderate, ∼200 W m -2 ). Equivalent heat-loss requirements and mean body temperature changes were evoked across participants. Forearm blood flow and vascular conductance were positively related to specific surface area during light work in men (r = 0.67 and r = 0

  6. Explaining Polarization Reversals in STEREO Wave Data

    Science.gov (United States)

    Breneman, A.; Cattell, C.; Wygant, J.; Kersten, K.; Wilson, L, B., III; Dai, L.; Colpitts, C.; Kellogg, P. J.; Goetz, K.; Paradise, A.

    2012-01-01

    Recently Breneman et al. reported observations of large amplitude lightning and transmitter whistler mode waves from two STEREO passes through the inner radiation belt (Lpaper. We show, with a combination of observations and simulated wave superposition, that these polarization reversals are due to the beating of an incident electromagnetic whistler mode wave at 21.4 kHz and linearly polarized, symmetric lower hybrid sidebands Doppler-shifted from the incident wave by +/-200 Hz. The existence of the lower hybrid waves is consistent with the parametric decay mechanism of Lee and Kuo whereby an incident whistler mode wave decays into symmetric, short wavelength lower hybrid waves and a purely growing (zero-frequency) mode. Like the lower hybrid waves, the purely growing mode is Doppler-shifted by 200 Hz as observed on STEREO. This decay mechanism in the upper ionosphere has been previously reported at equatorial latitudes and is thought to have a direct connection with explosive spread F enhancements. As such it may represent another dissipation mechanism of VLF wave energy in the ionosphere and may help to explain a deficit of observed lightning and transmitter energy in the inner radiation belts as reported by Starks et al.

  7. Explaining Global Secularity: Existential Security or Education?

    Directory of Open Access Journals (Sweden)

    Claude M. J. Braun

    2012-11-01

    Full Text Available At the time of data analysis for this report there were 193 countries in the world. Various institutions – the United Nations, the World Health Organization, the CIA, the World Values Survey, Gallup, and many others – have performed sophisticated statistical analyses on cross-national data. The present investigation demonstrates that valid and reliable data concerning religiosity and secularity exist for most countries and that these data are comparable. Cross-national data relating to social, political, economic and cultural aspects of life were tested for correlation with religiosity/secularity. In contrast to the most widely accepted general account of secularity, the Existential Security Framework (ESF; Norris & Inglehart, 2004, secularity was not most highly related to material security, though these were highly related. Rather, secularity was most strongly related to the degree of formal education attained. Material security explained no significant variance beyond education. Thus, religion’s primary function in the world today is being replaced, not so much by the pseudo-materialistic supplication for better living conditions as posited by the ESF, but by contemporary education – extensive knowledge of contemporary cultures, philosophy, modes of thought or processes of reasoning.

  8. Microeconomic principles explain an optimal genome size in bacteria.

    Science.gov (United States)

    Ranea, Juan A G; Grant, Alastair; Thornton, Janet M; Orengo, Christine A

    2005-01-01

    Bacteria can clearly enhance their survival by expanding their genetic repertoire. However, the tight packing of the bacterial genome and the fact that the most evolved species do not necessarily have the biggest genomes suggest there are other evolutionary factors limiting their genome expansion. To clarify these restrictions on size, we studied those protein families contributing most significantly to bacterial-genome complexity. We found that all bacteria apply the same basic and ancestral 'molecular technology' to optimize their reproductive efficiency. The same microeconomics principles that define the optimum size in a factory can also explain the existence of a statistical optimum in bacterial genome size. This optimum is reached when the bacterial genome obtains the maximum metabolic complexity (revenue) for minimal regulatory genes (logistic cost).

  9. Convergence and divergence, a concept for explaining drug actions.

    Science.gov (United States)

    Watanabe, Takehiko; Kamisaki, Yoshinori; Timmerman, Henk

    2004-10-01

    For the teaching and/or learning about drug actions and for the discovery and development of new drugs, it is important to understand how drugs act on living bodies. So far, there has been no clear description on the general principle of drug action in pharmacology textbooks. We propose two principles to depict the action mechanism of drugs. The first is that most, if not all, drugs act on proteins at the molecular level, that is, enzymes, receptors, ion channels, and transporters. The second is that a drug may cause divergent or convergent responses, resulting in changes of a physiological or pathological function of the human body. The concept of divergence and convergence can be used to explain the complex individuality of drug actions.

  10. Do differences in childhood diet explain the reduced overweight risk in breastfed children?

    NARCIS (Netherlands)

    Scholtens, Salome; Brunekreef, Bert; Smit, Henriette A; Gast, Gerrie-Cor M; Hoekstra, Maarten O; de Jongste, Johan C; Postma, Dirkje S; Gerritsen, Jorrit; Seidell, Jaap C; Wijga, Alet H

    2008-01-01

    Breastfeeding has been associated with a reduced risk of overweight later in life. This study investigates whether differences in diet and lifestyle at 7 years of age between breastfed and formula-fed children can explain the difference in overweight prevalence at 8 years of age. We studied 2,043

  11. Do Differences in Childhood Diet Explain the Reduced Overweight Risk in Breastfed Children?

    NARCIS (Netherlands)

    Scholtens, Salome; Brunekreef, Bert; Smit, Henriette A.; Gast, Gerrie-Cor M.; Hoekstra, Maarten O.; De Jongste, Johan C.; Postma, Dirkje S.; Gerritsen, Jorrit; Seidell, Jaap C.; Wijga, Alet H.

    2008-01-01

    Breastfeeding has been associated with a reduced risk of overweight later in life. This study investigates whether differences in diet and lifestyle at 7 years of age between breastfed and formula-fed children can explain the difference in overweight prevalence at 8 years of age. We studied 2,043

  12. Social Community: A Mechanism to Explain the Success of STEM Minority Mentoring Programs

    Science.gov (United States)

    Mondisa, Joi-Lynn; McComb, Sara A.

    2015-01-01

    Social community may be a mechanism that explains the success of minority mentoring programs. We define a social community as an environment where like-minded individuals engage in dynamic, multidirectional interactions that facilitate social support. In this conceptual article, we propose a social community model for science, technology,…

  13. Explaining Academic Progress via Combining Concepts of Integration Theory and Rational Choice Theory.

    Science.gov (United States)

    Beekhoven, S.; De Jong, U.; Van Hout, H.

    2002-01-01

    Compared elements of rational choice theory and integration theory on the basis of their power to explain variance in academic progress. Asserts that the concepts should be combined, and the distinction between social and academic integration abandoned. Empirical analysis showed that an extended model, comprising both integration and rational…

  14. Exposure to Pre- and Perinatal Risk Factors Partially Explains Mean Differences in Self-Regulation between Races.

    Science.gov (United States)

    Barnes, J C; Boutwell, Brian B; Miller, J Mitchell; DeShay, Rashaan A; Beaver, Kevin M; White, Norman

    2016-01-01

    To examine whether differential exposure to pre- and perinatal risk factors explained differences in levels of self-regulation between children of different races (White, Black, Hispanic, Asian, and Other). Multiple regression models based on data from the Early Childhood Longitudinal Study, Birth Cohort (n ≈ 9,850) were used to analyze the impact of pre- and perinatal risk factors on the development of self-regulation at age 2 years. Racial differences in levels of self-regulation were observed. Racial differences were also observed for 9 of the 12 pre-/perinatal risk factors. Multiple regression analyses revealed that a portion of the racial differences in self-regulation was explained by differential exposure to several of the pre-/perinatal risk factors. Specifically, maternal age at childbirth, gestational timing, and the family's socioeconomic status were significantly related to the child's level of self-regulation. These factors accounted for a statistically significant portion of the racial differences observed in self-regulation. The findings indicate racial differences in self-regulation may be, at least partially, explained by racial differences in exposure to pre- and perinatal risk factors.

  15. Light Absorption in Coralline Algae (Rhodophyta: A Morphological and Functional Approach to Understanding Species Distribution in a Coral Reef Lagoon

    Directory of Open Access Journals (Sweden)

    Román M. Vásquez-Elizondo

    2017-09-01

    Full Text Available Red coralline algae are a cosmopolitan group with the ability to precipitate CaCO3 within the walls of their vegetative cells. The resultant carbonate structure is key for explaining their ecological success, as it provides protection against herbivores and resistance to water motion. However, its potential contribution to enhance thallus light absorption efficiency through multiple light scattering on algal skeleton, similar to the effect documented for scleractinian corals, has not been yet investigated. Here, we initiate this analysis, characterizing thallus optical properties of three coralline species, which differed in pigment content and thallus mass area (TMA, gDW m−2. The three species, the rhodolith Neogoniolithon sp., the crustose coralline alga (CCA, Lithothamnion sp., and the articulated alga Amphiroa tribulus, represent the more distinctive coralline growth-forms and are able to colonize contrasting light environments in Caribbean coral reefs. The thicker thalli of the rhodoliths were the most efficient light collectors, as evidenced by their higher pigment absorption efficiency (a*Chla; m2 mgChla−1 and photosynthetic rates per unit area. This could explain rhodolith success in oligotrophic, highly illuminated reef environments. In contrast, the thinner thalli of the CCA, a low-light specialist, showed the highest metabolic rates normalized to mass and the highest light absorption efficiencies per unit mass (a*M; m2 gdw−1. Therefore, the ecological success of the CCA in cryptic habitats within the reef cannot be explained only by its low-light physiology, but also by its capacity to reduce the structural costs of their thalli, and thus of its new growth. Lastly, the ecological success of Amphiroa tribulus, which displayed intermediate values for the efficiency of light absorption, metabolic rates and TMA, was explained by its ability to construct the largest light collectors (algal canopies thanks to the presence of flexible

  16. Can sustained arousal explain the Chronic Fatigue Syndrome?

    Directory of Open Access Journals (Sweden)

    Eriksen Hege R

    2009-02-01

    Full Text Available Abstract We present an integrative model of disease mechanisms in the Chronic Fatigue Syndrome (CFS, unifying empirical findings from different research traditions. Based upon the Cognitive activation theory of stress (CATS, we argue that new data on cardiovascular and thermoregulatory regulation indicate a state of permanent arousal responses – sustained arousal – in this condition. We suggest that sustained arousal can originate from different precipitating factors (infections, psychosocial challenges interacting with predisposing factors (genetic traits, personality and learned expectancies (classical and operant conditioning. Furthermore, sustained arousal may explain documented alterations by establishing vicious circles within immunology (Th2 (humoral vs Th1 (cellular predominance, endocrinology (attenuated HPA axis, skeletal muscle function (attenuated cortical activation, increased oxidative stress and cognition (impaired memory and information processing. Finally, we propose a causal link between sustained arousal and the experience of fatigue. The model of sustained arousal embraces all main findings concerning CFS disease mechanisms within one theoretical framework.

  17. Carbonatite ring-complexes explained by caldera-style volcanism.

    Science.gov (United States)

    Andersson, Magnus; Malehmir, Alireza; Troll, Valentin R; Dehghannejad, Mahdieh; Juhlin, Christopher; Ask, Maria

    2013-01-01

    Carbonatites are rare, carbonate-rich magmatic rocks that make up a minute portion of the crust only, yet they are of great relevance for our understanding of crustal and mantle processes. Although they occur in all continents and from Archaean to present, the deeper plumbing system of carbonatite ring-complexes is usually poorly constrained. Here, we show that carbonatite ring-complexes can be explained by caldera-style volcanism. Our geophysical investigation of the Alnö carbonatite ring-complex in central Sweden identifies a solidified saucer-shaped magma chamber at ~3 km depth that links to surface exposures through a ring fault system. Caldera subsidence during final stages of activity caused carbonatite eruptions north of the main complex, providing the crucial element to connect plutonic and eruptive features of carbonatite magmatism. The way carbonatite magmas are stored, transported and erupt at the surface is thus comparable to known emplacement styles from silicic calderas.

  18. Once upon an algorithm how stories explain computing

    CERN Document Server

    Erwig, Martin

    2017-01-01

    How Hansel and Gretel, Sherlock Holmes, the movie Groundhog Day, Harry Potter, and other familiar stories illustrate the concepts of computing. Picture a computer scientist, staring at a screen and clicking away frantically on a keyboard, hacking into a system, or perhaps developing an app. Now delete that picture. In Once Upon an Algorithm, Martin Erwig explains computation as something that takes place beyond electronic computers, and computer science as the study of systematic problem solving. Erwig points out that many daily activities involve problem solving. Getting up in the morning, for example: You get up, take a shower, get dressed, eat breakfast. This simple daily routine solves a recurring problem through a series of well-defined steps. In computer science, such a routine is called an algorithm. Erwig illustrates a series of concepts in computing with examples from daily life and familiar stories. Hansel and Gretel, for example, execute an algorithm to get home from the forest. The movie Groundho...

  19. Elements Explaining Learning Clinical Reasoning Using Simulation Games

    Directory of Open Access Journals (Sweden)

    Jaana-Maija Koivisto

    2016-12-01

    Full Text Available This article presents the findings on which elements in a game-based simulation affect learning clinical reasoning in nursing education. By using engaging gaming elements in virtual simulations and integrating the clinical reasoning process into game mechanics, games can enhance learning clinical reasoning and offer meaningful learning experiences. The study was designed to explore how nursing students experience gaming and learning when playing a simulation game, as well as which gaming elements explain learning clinical reasoning. The data was collected by questionnaire from nursing students (N = 166 in autumn 2014 over thirteen gaming sessions. The findings showed that usability, application of nursing knowledge, and exploration have the most impact on learning clinical reasoning when playing simulation games. Findings also revealed that authentic patient-related experiences, feedback, and reflection have an indirect effect on learning clinical reasoning. Based on these results, more efficient simulation games to improve clinical reasoning may be developed.   

  20. Explaining Post-Communist Respect for Civil Liberty: A Multi-Methods Test

    DEFF Research Database (Denmark)

    Skaaning, Svend Erik

    2007-01-01

    This article explains the level of respect for civil liberty in post-communist countries. The methodological triangulation employs both QCA methods and OLS-regression to test the influence of structural conditions, the democratization literature emphasizes. The results show that the political leg...... the results of the methods applied diverge. Expect a lack of congruence given their different assumptions and logics. As to the QCA methods in specific, they are apparently valuable supplements, and at times even plausible alternatives, to standard statistical tests....

  1. Childhood trajectories of anxiousness and disruptiveness explain the association between early-life adversity and attempted suicide.

    Science.gov (United States)

    Wanner, B; Vitaro, F; Tremblay, R E; Turecki, G

    2012-11-01

    Suicidal behavior is frequently associated with a history of childhood abuse yet it remains unclear precisely how early life adversity may increase suicide risk later in life. As such, our aim was to examine whether lifetime trajectories of disruptiveness and anxiousness trait dysregulation explain the association between childhood adversity and suicidal behavior; and moreover, to test the potential modifying effects of mental disorders on these associations. A sample of 1776 individuals from a prospective school-based cohort followed longitudinally for over 22 years was investigated. We tested the influence of disruptiveness and anxiousness trajectories from age 6 to 12 years on the association between childhood adversity (i.e. sexual and physical abuse) and history of suicide attempts (SA) using logistic regression models. Both adolescent externalizing and internalizing Axis I disorders and gender were tested as potential modifiers of these associations. Four distinct longitudinal trajectories were identified for both disruptiveness and anxiousness. The high disruptiveness trajectory accounted for the association between childhood adversity and SA, but only for females. The high anxiousness trajectory also explained the association between adversity and SA; however, in this case it was not sex but mental disorders that influenced the potency of the mediating effect. More specifically, anxiousness fully explained the effect of adversity on SA in the presence of externalizing disorders, whereas in the absence of these disorders, this effect was significantly attenuated. This study provides evidence that both disruptiveness and anxiousness play an important role in explaining the relationship between childhood adversity and SA.

  2. Meanings at Hand: Coordinating Semiotic Resources in Explaining Mathematical Terms in Classroom Discourse

    Science.gov (United States)

    Heller, Vivien

    2016-01-01

    The article examines how diverse semiotic resources are made available for explaining mathematical terms in a fifth-grade classroom. Situated within the methodological framework developed by conversation analysis and the analysis of embodiment-in-interaction, the study deals with two instances of a classroom episode in each of which participants…

  3. Reduced GABAergic inhibition explains cortical hyperexcitability in the wobbler mouse model of ALS

    DEFF Research Database (Denmark)

    Nieto-Gonzalez, Jose Luis; Moser, Jakob; Lauritzen, Martin

    2011-01-01

    mice. Also, miniature inhibitory postsynaptic currents recorded under blockade of action potentials were decreased by 64%. Tonic inhibition mediated by extrasynaptic GABA(A) receptors was reduced by 87%. In agreement, we found a decreased density of parvalbumin- and somatostatin-positive inhibitory...... inhibition, which might explain the cortical hyperexcitability in wobbler mice....

  4. Factors explaining the level of voluntary human capital disclosure in the Brazilian capital market

    Directory of Open Access Journals (Sweden)

    Fernando Batista Fontana

    2013-04-01

    Full Text Available Purpose: This paper presents a study on factors explaining the level of voluntary human capital information in companies with shares in the Brazilian stock exchange. Assuming the existence of information asymmetry between managers and shareholders, agency theory states that disclosure might lead to a reduction in agency costs. The proprietary costs theory indicates that information disclosure might increase the company’s costs. According to these theories, the likelihood that the managers will voluntarily disclose information depends on certain factors that are characteristic of the company. Understanding the disclosure of information regarding intangible assets, specifically human capital, has strategic relevance for enterprises because these features, although not always recorded in accounting, represent a competitive business edge in the current economy.Design/methodology/approach: The study examined 145 annual reports, representing 29 companies in the period of 2005-2009. The level of voluntary disclosure was determined through content analysis of annual reports using representative indicators of human capital information.Findings: The statistical results indicate that factors such as size, debt, growth and time of registration with the brazilian Securities and Exchange Commission explain the level of voluntary human capital disclosure of the companies studied.Originality/value: An important contribution of this research is the formulation and non-repudiation of the time of registration with the CVM hypothesis as a factor that explains the level of human capital disclosure because none of the revised studies have tested this hypothesis.

  5. Explaining clinical behaviors using multiple theoretical models

    Directory of Open Access Journals (Sweden)

    Eccles Martin P

    2012-10-01

    Full Text Available Abstract Background In the field of implementation research, there is an increased interest in use of theory when designing implementation research studies involving behavior change. In 2003, we initiated a series of five studies to establish a scientific rationale for interventions to translate research findings into clinical practice by exploring the performance of a number of different, commonly used, overlapping behavioral theories and models. We reflect on the strengths and weaknesses of the methods, the performance of the theories, and consider where these methods sit alongside the range of methods for studying healthcare professional behavior change. Methods These were five studies of the theory-based cognitions and clinical behaviors (taking dental radiographs, performing dental restorations, placing fissure sealants, managing upper respiratory tract infections without prescribing antibiotics, managing low back pain without ordering lumbar spine x-rays of random samples of primary care dentists and physicians. Measures were derived for the explanatory theoretical constructs in the Theory of Planned Behavior (TPB, Social Cognitive Theory (SCT, and Illness Representations specified by the Common Sense Self Regulation Model (CSSRM. We constructed self-report measures of two constructs from Learning Theory (LT, a measure of Implementation Intentions (II, and the Precaution Adoption Process. We collected data on theory-based cognitions (explanatory measures and two interim outcome measures (stated behavioral intention and simulated behavior by postal questionnaire survey during the 12-month period to which objective measures of behavior (collected from routine administrative sources were related. Planned analyses explored the predictive value of theories in explaining variance in intention, behavioral simulation and behavior. Results Response rates across the five surveys ranged from 21% to 48%; we achieved the target sample size for three of

  6. Explaining clinical behaviors using multiple theoretical models.

    Science.gov (United States)

    Eccles, Martin P; Grimshaw, Jeremy M; MacLennan, Graeme; Bonetti, Debbie; Glidewell, Liz; Pitts, Nigel B; Steen, Nick; Thomas, Ruth; Walker, Anne; Johnston, Marie

    2012-10-17

    In the field of implementation research, there is an increased interest in use of theory when designing implementation research studies involving behavior change. In 2003, we initiated a series of five studies to establish a scientific rationale for interventions to translate research findings into clinical practice by exploring the performance of a number of different, commonly used, overlapping behavioral theories and models. We reflect on the strengths and weaknesses of the methods, the performance of the theories, and consider where these methods sit alongside the range of methods for studying healthcare professional behavior change. These were five studies of the theory-based cognitions and clinical behaviors (taking dental radiographs, performing dental restorations, placing fissure sealants, managing upper respiratory tract infections without prescribing antibiotics, managing low back pain without ordering lumbar spine x-rays) of random samples of primary care dentists and physicians. Measures were derived for the explanatory theoretical constructs in the Theory of Planned Behavior (TPB), Social Cognitive Theory (SCT), and Illness Representations specified by the Common Sense Self Regulation Model (CSSRM). We constructed self-report measures of two constructs from Learning Theory (LT), a measure of Implementation Intentions (II), and the Precaution Adoption Process. We collected data on theory-based cognitions (explanatory measures) and two interim outcome measures (stated behavioral intention and simulated behavior) by postal questionnaire survey during the 12-month period to which objective measures of behavior (collected from routine administrative sources) were related. Planned analyses explored the predictive value of theories in explaining variance in intention, behavioral simulation and behavior. Response rates across the five surveys ranged from 21% to 48%; we achieved the target sample size for three of the five surveys. For the predictor variables

  7. Host-related factors explaining interindividual variability of carotenoid bioavailability and tissue concentrations in humans

    DEFF Research Database (Denmark)

    Bohn, Torsten; Desmarchelier, Charles; Dragsted, Lars Ove

    2017-01-01

    .g. smoking), gender and age, as well as genetic variations including single nucleotide polymorphisms that govern carotenoid metabolism. These are expected to explain interindividual differences that contribute to carotenoid uptake, distribution, metabolism and excretion, and therefore possibly also...

  8. Seasonality of absolute humidity explains seasonality of influenza-like illness in Vietnam.

    Science.gov (United States)

    Thai, Pham Quang; Choisy, Marc; Duong, Tran Nhu; Thiem, Vu Dinh; Yen, Nguyen Thu; Hien, Nguyen Tran; Weiss, Daniel J; Boni, Maciej F; Horby, Peter

    2015-12-01

    Experimental and ecological studies have shown the role of climatic factors in driving the epidemiology of influenza. In particular, low absolute humidity (AH) has been shown to increase influenza virus transmissibility and has been identified to explain the onset of epidemics in temperate regions. Here, we aim to study the potential climatic drivers of influenza-like illness (ILI) epidemiology in Vietnam, a tropical country characterized by a high diversity of climates. We specifically focus on quantifying and explaining the seasonality of ILI. We used 18 years (1993-2010) of monthly ILI notifications aggregated by province (52) and monthly climatic variables (minimum, mean, maximum temperatures, absolute and relative humidities, rainfall and hours of sunshine) from 67 weather stations across Vietnam. Seasonalities were quantified from global wavelet spectra, using the value of the power at the period of 1 year as a measure of the intensity of seasonality. The 7 climatic time series were characterized by 534 summary statistics which were entered into a regression tree to identify factors associated with the seasonality of AH. Results were extrapolated to the global scale using simulated climatic times series from the NCEP/NCAR project. The intensity of ILI seasonality in Vietnam is best explained by the intensity of AH seasonality. We find that ILI seasonality is weak in provinces experiencing weak seasonal fluctuations in AH (annual power power >17.6). In Vietnam, AH and ILI are positively correlated. Our results identify a role for AH in driving the epidemiology of ILI in a tropical setting. However, in contrast to temperate regions, high rather than low AH is associated with increased ILI activity. Fluctuation in AH may be the climate factor that underlies and unifies the seasonality of ILI in both temperate and tropical regions. Alternatively, the mechanism of action of AH on disease transmission may be different in cold-dry versus hot-humid settings

  9. Instructional Support for Novice Law Students: Reducing Search Processes and Explaining Concepts in Cases

    NARCIS (Netherlands)

    Nievelstein, Fleurie; Van Gog, Tamara; Van Dijck, Gijs; Boshuizen, Els

    2010-01-01

    Nievelstein, F., Van Gog, T., Van Dijck, C., & Boshuizen, H. P. A. (2011). Instructional support for novice law students: Reducing search processes and explaining concepts in cases. Applied Cognitive Psychology, 25(3), 408-413. doi:10.1002/acp.1707

  10. Hypothesis: Gene-rich plastid genomes in red algae may be an outcome of nuclear genome reduction.

    Science.gov (United States)

    Qiu, Huan; Lee, Jun Mo; Yoon, Hwan Su; Bhattacharya, Debashish

    2017-06-01

    Red algae (Rhodophyta) putatively diverged from the eukaryote tree of life >1.2 billion years ago and are the source of plastids in the ecologically important diatoms, haptophytes, and dinoflagellates. In general, red algae contain the largest plastid gene inventory among all such organelles derived from primary, secondary, or additional rounds of endosymbiosis. In contrast, their nuclear gene inventory is reduced when compared to their putative sister lineage, the Viridiplantae, and other photosynthetic lineages. The latter is thought to have resulted from a phase of genome reduction that occurred in the stem lineage of Rhodophyta. A recent comparative analysis of a taxonomically broad collection of red algal and Viridiplantae plastid genomes demonstrates that the red algal ancestor encoded ~1.5× more plastid genes than Viridiplantae. This difference is primarily explained by more extensive endosymbiotic gene transfer (EGT) in the stem lineage of Viridiplantae, when compared to red algae. We postulate that limited EGT in Rhodophytes resulted from the countervailing force of ancient, and likely recurrent, nuclear genome reduction. In other words, the propensity for nuclear gene loss led to the retention of red algal plastid genes that would otherwise have undergone intracellular gene transfer to the nucleus. This hypothesis recognizes the primacy of nuclear genome evolution over that of plastids, which have no inherent control of their gene inventory and can change dramatically (e.g., secondarily non-photosynthetic eukaryotes, dinoflagellates) in response to selection acting on the host lineage. © 2017 Phycological Society of America.

  11. Explaining sexual harassment judgments: looking beyond gender of the rater.

    Science.gov (United States)

    O'Connor, Maureen; Gutek, Barbara A; Stockdale, Margaret; Geer, Tracey M; Melançon, Renée

    2004-02-01

    In two decades of research on sexual harassment, one finding that appears repeatedly is that gender of the rater influences judgments about sexual harassment such that women are more likely than men to label behavior as sexual harassment. Yet, sexual harassment judgments are complex, particularly in situations that culminate in legal proceedings. And, this one variable, gender, may have been overemphasized to the exclusion of other situational and rater characteristic variables. Moreover, why do gender differences appear? As work by Wiener and his colleagues have done (R. L. Wiener et al., 2002; R. L. Wiener & L. Hurt, 2000; R. L. Wiener, L. Hurt, B. Russell, K. Mannen, & C. Gasper, 1997), this study attempts to look beyond gender to answer this question. In the studies reported here, raters (undergraduates and community adults), either read a written scenario or viewed a videotaped reenactment of a sexual harassment trial. The nature of the work environment was manipulated to see what, if any, effect the context would have on gender effects. Additionally, a number of rater characteristics beyond gender were measured, including ambivalent sexism attitudes of the raters, their judgments of complainant credibility, and self-referencing that might help explain rater judgments. Respondent gender, work environment, and community vs. student sample differences produced reliable differences in sexual harassment ratings in both the written and video trial versions of the study. The gender and sample differences in the sexual harassment ratings, however, are explained by a model which incorporates hostile sexism, perceptions of the complainants credibility, and raters' own ability to put themselves in the complainant's position (self-referencing).

  12. Why Do Things Fall? How to Explain Why Gravity Is Not a Force

    Science.gov (United States)

    Stannard, Warren B.

    2018-01-01

    In most high school physics classes, gravity is described as an attractive force between two masses as formulated by Newton over 300 years ago. Einstein's general theory of relativity implies that gravitational effects are instead the result of a "curvature" of space-time. However, explaining why things fall without resorting to Newton's…

  13. Amplitude saturation of MEMS resonators explained by autoparametric resonance

    International Nuclear Information System (INIS)

    Van der Avoort, C; Bontemps, J J M; Steeneken, P G; Le Phan, K; Van Beek, J T M; Van der Hout, R; Hulshof, J; Fey, R H B

    2010-01-01

    This paper describes a phenomenon that limits the power handling of MEMS resonators. It is observed that above a certain driving level, the resonance amplitude becomes independent of the driving level. In contrast to previous studies of power handling of MEMS resonators, it is found that this amplitude saturation cannot be explained by nonlinear terms in the spring constant or electrostatic force. Instead we show that the amplitude in our experiments is limited by nonlinear terms in the equation of motion which couple the in-plane length-extensional resonance mode to one or more out-of-plane (OOP) bending modes. We present experimental evidence for the autoparametric excitation of these OOP modes using a vibrometer. The measurements are compared to a model that can be used to predict a power-handling limit for MEMS resonators

  14. Amplitude saturation of MEMS resonators explained by autoparametric resonance

    Energy Technology Data Exchange (ETDEWEB)

    Van der Avoort, C; Bontemps, J J M; Steeneken, P G; Le Phan, K; Van Beek, J T M [NXP Research, Eindhoven (Netherlands); Van der Hout, R; Hulshof, J [Department of Mathematics, VU University—Faculty of Sciences, De Boelelaan 1081a, 1081 HV Amsterdam (Netherlands); Fey, R H B, E-mail: cas.van.der.avoort@nxp.com [Department of Mechanical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB, Eindhoven (Netherlands)

    2010-10-15

    This paper describes a phenomenon that limits the power handling of MEMS resonators. It is observed that above a certain driving level, the resonance amplitude becomes independent of the driving level. In contrast to previous studies of power handling of MEMS resonators, it is found that this amplitude saturation cannot be explained by nonlinear terms in the spring constant or electrostatic force. Instead we show that the amplitude in our experiments is limited by nonlinear terms in the equation of motion which couple the in-plane length-extensional resonance mode to one or more out-of-plane (OOP) bending modes. We present experimental evidence for the autoparametric excitation of these OOP modes using a vibrometer. The measurements are compared to a model that can be used to predict a power-handling limit for MEMS resonators.

  15. Explaining international co-authorship in global environmental change research

    Energy Technology Data Exchange (ETDEWEB)

    Jappe, A.

    2006-04-15

    This paper maps the domain of earth and environmental sciences (EES) and investigates the relationship between cognitive problem structures and internationalisation patterns, drawing on the concepts of systemic versus cumulative global environmental change (GEC) and mutual task dependence in scientific fields. We find that scientific output concentration and internationalisation are significantly higher in the systemic GEC fields of Meteorology and Atmospheric Sciences and Oceanography than in the cumulative GEC fields Ecology and Water Resources. The relationship is explained by stronger mutual task dependence in systemic GEC fields. In contrast, the portion of co-authorships with developing, emerging and transition countries among all international publications is larger for Water Resources than for the three other fields, consistent with the most pressing needs for STI capacity development in these countries. (orig.)

  16. Explaining human uniqueness: genome interactions with environment, behaviour and culture.

    Science.gov (United States)

    Varki, Ajit; Geschwind, Daniel H; Eichler, Evan E

    2008-10-01

    What makes us human? Specialists in each discipline respond through the lens of their own expertise. In fact, 'anthropogeny' (explaining the origin of humans) requires a transdisciplinary approach that eschews such barriers. Here we take a genomic and genetic perspective towards molecular variation, explore systems analysis of gene expression and discuss an organ-systems approach. Rejecting any 'genes versus environment' dichotomy, we then consider genome interactions with environment, behaviour and culture, finally speculating that aspects of human uniqueness arose because of a primate evolutionary trend towards increasing and irreversible dependence on learned behaviours and culture - perhaps relaxing allowable thresholds for large-scale genomic diversity.

  17. The Role of Aggressive Personality and Family Relationships in Explaining Family Conflict

    OpenAIRE

    Horwitz, Briana N.; Ganiban, Jody M.; Spotts, Erica L.; Lichtenstein, Paul; Reiss, David; Neiderhiser, Jenae M.

    2011-01-01

    This study investigated whether genetic and environmental influences on global family conflict are explained by parents’ personality, marital quality, and negative parenting. The sample comprised 876 same-sex pairs of twins, their spouse, and one adolescent child per twin from the Twin and Offspring Study in Sweden (TOSS). Genetic influences on aggressive personality were correlated with genetic influences on global family conflict. Nonshared environmental influences on marital quality and ne...

  18. The Role of Culture, Competitiveness and Economic Performance in Explaining Academic Performance: A Global Market Analysis for International Student Segmentation

    Science.gov (United States)

    Baumann, Chris; Hamin

    2011-01-01

    A nation's culture, competitiveness and economic performance explain academic performance. Partial Least Squares (PLS) testing of 2252 students shows culture affects competitiveness and academic performance. Culture and economic performance each explain 32%; competitiveness 36%. The model predicts academic performance when culture, competitiveness…

  19. Factors that Explain the Principal-Agent Relationship in Six Companies of the City of Manizales

    Directory of Open Access Journals (Sweden)

    Tania Mackenzie Torres

    2016-04-01

    Full Text Available This study aims to determine the factors that explain the relationship between principal and agent in six institutions from different economic sectors (education, services, metallurgy, solidarity and financial economy in the city of Manizales. The study is based on the conceptual foundations of the neo-institutional current, which are framed in neoliberal and microeconomic models interpreted in the light of agency theory. As research strategy, the methodology consists of a multiple case study, which focuses its interest on a number of cases where each case has its own identity. The factors that determine the principal-agent relationship in these six institutions are explained by contract, incentives and controls; motivational factors, both intrinsic and extrinsic, are also identified.

  20. Income Inequality Explains Why Economic Growth Does Not Always Translate to an Increase in Happiness.

    Science.gov (United States)

    Oishi, Shigehiro; Kesebir, Selin

    2015-10-01

    One of the most puzzling social science findings in the past half century is the Easterlin paradox: Economic growth within a country does not always translate into an increase in happiness. We provide evidence that this paradox can be partly explained by income inequality. In two different data sets covering 34 countries, economic growth was not associated with increases in happiness when it was accompanied by growing income inequality. Earlier instances of the Easterlin paradox (i.e., economic growth not being associated with increasing happiness) can thus be explained by the frequent concurrence of economic growth and growing income inequality. These findings suggest that a more even distribution of growth in national wealth may be a precondition for raising nationwide happiness. © The Author(s) 2015.

  1. A Little Knowledge of Ground Motion: Explaining 3-D Physics-Based Modeling to Engineers

    Science.gov (United States)

    Porter, K.

    2014-12-01

    Users of earthquake planning scenarios require the ground-motion map to be credible enough to justify costly planning efforts, but not all ground-motion maps are right for all uses. There are two common ways to create a map of ground motion for a hypothetical earthquake. One approach is to map the median shaking estimated by empirical attenuation relationships. The other uses 3-D physics-based modeling, in which one analyzes a mathematical model of the earth's crust near the fault rupture and calculates the generation and propagation of seismic waves from source to ground surface by first principles. The two approaches produce different-looking maps. The more-familiar median maps smooth out variability and correlation. Using them in a planning scenario can lead to a systematic underestimation of damage and loss, and could leave a community underprepared for realistic shaking. The 3-D maps show variability, including some very high values that can disconcert non-scientists. So when the USGS Science Application for Risk Reduction's (SAFRR) Haywired scenario project selected 3-D maps, it was necessary to explain to scenario users—especially engineers who often use median maps—the differences, advantages, and disadvantages of the two approaches. We used authority, empirical evidence, and theory to support our choice. We prefaced our explanation with SAFRR's policy of using the best available earth science, and cited the credentials of the maps' developers and the reputation of the journal in which they published the maps. We cited recorded examples from past earthquakes of extreme ground motions that are like those in the scenario map. We explained the maps on theoretical grounds as well, explaining well established causes of variability: directivity, basin effects, and source parameters. The largest mapped motions relate to potentially unfamiliar extreme-value theory, so we used analogies to human longevity and the average age of the oldest person in samples of

  2. Pulsar TeV Halos Explain the Diffuse TeV Excess Observed by Milagro.

    Science.gov (United States)

    Linden, Tim; Buckman, Benjamin J

    2018-03-23

    Milagro observations have found bright, diffuse TeV emission concentrated along the galactic plane of the Milky Way. The intensity and spectrum of this emission is difficult to explain with current models of hadronic γ-ray production, and has been named the "TeV excess." We show that TeV emission from pulsars naturally explains this excess. Recent observations have detected "TeV halos" surrounding pulsars that are either nearby or particularly luminous. Extrapolating this emission to the full population of Milky Way pulsars indicates that the ensemble of "subthreshold" sources necessarily produces bright TeV emission diffusively along the Milky Way plane. Models indicate that the TeV halo γ-ray flux exceeds that from hadronic γ rays above an energy of ∼500  GeV. Moreover, the spectrum and intensity of TeV halo emission naturally matches the TeV excess. Finally, we show that upcoming HAWC observations will resolve a significant fraction of the TeV excess into individual TeV halos, conclusively confirming, or ruling out, this model.

  3. The doctor in the hot seat - using the media to explain effects of radiation

    International Nuclear Information System (INIS)

    Berry, R.J.

    1993-01-01

    The author explains how the public perceives the medical profession, what the public expects of the medical profession, how to communicate with the public and precises the role of the medical profession by providing information to the public and during radiological emergencies

  4. Stepwise latent class models for explaining group-level putcomes using discrete individual-level predictors

    NARCIS (Netherlands)

    Bennink, Margot; Croon, M.A.; Vermunt, J.K.

    2015-01-01

    Explaining group-level outcomes from individual-level predictors requires aggregating the individual-level scores to the group level and correcting the group-level estimates for measurement errors in the aggregated scores. However, for discrete variables it is not clear how to perform the

  5. What explains the Rural-Urban Gap in Infant Mortality — Household or Community Characteristics?

    NARCIS (Netherlands)

    E. Van de Poel (Ellen); O.A. O'Donnell (Owen); E.K.A. van Doorslaer (Eddy)

    2007-01-01

    textabstractThe rural-urban gap in infant mortality rates is explained using a new decomposition method that permits identification of the ontribution of unobserved heterogeneity at the household and the community level. Using Demographic and Health Survey data for six Francophone countries in

  6. Explaining the R{sub K} and R{sub K{sup *}} anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Diptimoy [Weizmann Institute of Science, Department of Particle Physics and Astrophysics, Rehovot (Israel)

    2017-10-15

    Recent LHCb results on R{sub K*}, the ratio of the branching fractions of B → K*μ{sup +}μ{sup -} to that of B → K*e{sup +}e{sup -}, for the dilepton invariant mass bins q{sup 2} ≡ m{sub ll}{sup 2} = [0.045-1.1] GeV{sup 2} and [1.1-6] GeV{sup 2} show approximately 2.5σ deviations from the corresponding Standard Model prediction in each of the bins. This, when combined with the measurement of R{sub K} (q{sup 2} = [1-6] GeV{sup 2}), a similar ratio for the decay to a pseudo-scalar meson, highly suggests lepton non-universal new physics in semi-leptonic B meson decays. In this work, we perform a model independent analysis of these potential new physics signals and identify the operators that do the best job in satisfying all these measurements. We show that heavy new physics, giving rise to q{sup 2} independent local 4-Fermi operators of scalar, pseudo-scalar, vector or axial-vector type, is unable to explain all the three measurements simultaneously, in particular R{sub K*} in the bin [0.045-1.1], within their experimental 1σ regions. We point out the possibility to explain R{sub K*} in the low bin by an additional light (

  7. BODE index versus GOLD classification for explaining anxious and depressive symptoms in patients with COPD – a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Burghuber Otto

    2009-01-01

    Full Text Available Abstract Background Anxiety and depression are common and treatable risk factors for re-hospitalisation and death in patients with COPD. The degree of lung function impairment does not sufficiently explain anxiety and depression. The BODE index allows a functional classification of COPD beyond FEV1. The aim of this cross-sectional study was (1 to test whether the BODE index is superior to the GOLD classification for explaining anxious and depressive symptoms; and (2 to assess which components of the BODE index are associated with these psychological aspects of COPD. Methods COPD was classified according to the GOLD stages based on FEV1%predicted in 122 stable patients with COPD. An additional four stage classification was constructed based on the quartiles of the BODE index. The hospital anxiety and depression scale was used to assess anxious and depressive symptoms. Results The overall prevalence of anxious and depressive symptoms was 49% and 52%, respectively. The prevalence of anxious symptoms increased with increasing BODE stages but not with increasing GOLD stages. The prevalence of depressive symptoms increased with both increasing GOLD and BODE stages. The BODE index was superior to FEV1%predicted for explaining anxious and depressive symptoms. Anxious symptoms were explained by dyspnoea. Depressive symptoms were explained by both dyspnoea and reduced exercise capacity. Conclusion The BODE index is superior to the GOLD classification for explaining anxious and depressive symptoms in COPD patients. These psychological consequences of the disease may play a role in future classification systems of COPD.

  8. Applying the theory of planned behaviour to explain HIV testing in antenatal settings in Addis Ababa - a cohort study

    Science.gov (United States)

    2011-01-01

    Background To facilitate access to the prevention of mother-to-child HIV transmission (PMTCT) services, HIV counselling and testing are offered routinely in antenatal care settings. Focusing a cohort of pregnant women attending public and private antenatal care facilities, this study applied an extended version of the Theory of Planned Behaviour (TPB) to explain intended- and actual HIV testing. Methods A sequential exploratory mixed methods study was conducted in Addis Ababa in 2009. The study involved first time antenatal attendees from public- and private health care facilities. Three Focus Group Discussions were conducted to inform the TPB questionnaire. A total of 3033 women completed the baseline TPB interviews, including attitudes, subjective norms, perceived behavioural control and intention with respect to HIV testing, whereas 2928 completed actual HIV testing at follow up. Data were analysed using descriptive statistics, Chi-square tests, Fisher's Exact tests, Internal consistency reliability, Pearson's correlation, Linear regression, Logistic regression and using Epidemiological indices. P-values < 0.05 was considered significant and 95% Confidence Interval (CI) was used for the odds ratio. Results The TPB explained 9.2% and 16.4% of the variance in intention among public- and private health facility attendees. Intention and perceived barriers explained 2.4% and external variables explained 7% of the total variance in HIV testing. Positive and negative predictive values of intention were 96% and 6% respectively. Across both groups, subjective norm explained a substantial amount of variance in intention, followed by attitudes. Women intended to test for HIV if they perceived social support and anticipated positive consequences following test performance. Type of counselling did not modify the link between intended and actual HIV testing. Conclusion The TPB explained substantial amount of variance in intention to test but was less sufficient in explaining

  9. Competition explains limited attention and perceptual resources: implications for perceptual load and dilution theories.

    Science.gov (United States)

    Scalf, Paige E; Torralbo, Ana; Tapia, Evelina; Beck, Diane M

    2013-01-01

    Both perceptual load theory and dilution theory purport to explain when and why task-irrelevant information, or so-called distractors are processed. Central to both explanations is the notion of limited resources, although the theories differ in the precise way in which those limitations affect distractor processing. We have recently proposed a neurally plausible explanation of limited resources in which neural competition among stimuli hinders their representation in the brain. This view of limited capacity can also explain distractor processing, whereby the competitive interactions and bias imposed to resolve the competition determine the extent to which a distractor is processed. This idea is compatible with aspects of both perceptual load and dilution models of distractor processing, but also serves to highlight their differences. Here we review the evidence in favor of a biased competition view of limited resources and relate these ideas to both classic perceptual load theory and dilution theory.

  10. Simple model to explain the temperature dependence of the lower hybrid current drive efficiency

    International Nuclear Information System (INIS)

    Ushigusa, K.

    1996-01-01

    Dissipated power in the spectral gap is taken into account in deriving analytically the lower hybrid current drive efficiency. The efficiency is determined by a minimum down-shifted phase velocity υ L and the quasi-linear velocity diffusion coefficient at the spectral gap D' W in addition to the original wave spectrum. To explain present experimental results in both JT-60 and ASDEX, υ L must be close to the Landau damping limit (υ L ∼ 2.7υ te ) and D' W must be the same order of magnitude as the collisional friction at υ L . With the suggested values of these two parameters from experimental results, the driven current is mainly determined by the launched wave spectrum, while most of the wave power is dissipated at the spectral gap. This characteristic can explain both the temperature and the N || dependence of the current drive efficiency. (author)

  11. Exposure to Pre- and Perinatal Risk Factors Partially Explains Mean Differences in Self-Regulation between Races.

    Directory of Open Access Journals (Sweden)

    J C Barnes

    Full Text Available To examine whether differential exposure to pre- and perinatal risk factors explained differences in levels of self-regulation between children of different races (White, Black, Hispanic, Asian, and Other.Multiple regression models based on data from the Early Childhood Longitudinal Study, Birth Cohort (n ≈ 9,850 were used to analyze the impact of pre- and perinatal risk factors on the development of self-regulation at age 2 years.Racial differences in levels of self-regulation were observed. Racial differences were also observed for 9 of the 12 pre-/perinatal risk factors. Multiple regression analyses revealed that a portion of the racial differences in self-regulation was explained by differential exposure to several of the pre-/perinatal risk factors. Specifically, maternal age at childbirth, gestational timing, and the family's socioeconomic status were significantly related to the child's level of self-regulation. These factors accounted for a statistically significant portion of the racial differences observed in self-regulation.The findings indicate racial differences in self-regulation may be, at least partially, explained by racial differences in exposure to pre- and perinatal risk factors.

  12. Memory loss after electroconvulsive treatment--may the sudden alleviation of depression-inducing memories explain patient despair?

    Science.gov (United States)

    Berg, John E

    2011-12-01

    Electroconvulsive treatment (ECT) has developed over 70 years to a modern, effective way of lifting depressive moods. Memory loss after electroconvulsive treatment is the only remaining relevant criticism of the treatment modality when considering the overall rate of remission from this treatment compared to all other treatment modalities. A depressive state impedes memory. After treatment memory improves on several qualities of cognition. However, comparing a person's memory ability from the months before depression started to the level after a course of ECT is never done, of obvious reasons. There are great clinical difficulties explaining who would develop memory problems, regardless of stimulation techniques, age or sex of the patient. The memory loss seen in some patients undergoing electroconvulsive treatment (ECT) is not explained by the treatment alone. After ECT unpleasant memories are disclosed rapidly and the patient may unconsciously try to defend herself by extending memory repression to other areas of memory. This may be unrelated to treatment modality, number of sessions or severity of depression. Psychological factors may partly explain why some patients unfold memory problems when the depression is rapidly lifted, rather than the treatment modality itself. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Phenotypic Characterization and Multivariate Analysis to Explain Body Conformation in Lesser Known Buffalo (Bubalus bubalis) from North India

    Science.gov (United States)

    Vohra, V.; Niranjan, S. K.; Mishra, A. K.; Jamuna, V.; Chopra, A.; Sharma, Neelesh; Jeong, Dong Kee

    2015-01-01

    Phenotypic characterization and body biometric in 13 traits (height at withers, body length, chest girth, paunch girth, ear length, tail length, length of tail up to switch, face length, face width, horn length, circumference of horn at base, distances between pin bone and hip bone) were recorded in 233 adult Gojri buffaloes from Punjab and Himachal Pradesh states of India. Traits were analysed by using varimax rotated principal component analysis (PCA) with Kaiser Normalization to explain body conformation. PCA revealed four components which explained about 70.9% of the total variation. First component described the general body conformation and explained 31.5% of total variation. It was represented by significant positive high loading of height at wither, body length, heart girth, face length and face width. The communality ranged from 0.83 (hip bone distance) to 0.45 (horn length) and unique factors ranged from 0.16 to 0.55 for all these 13 different biometric traits. Present study suggests that first principal component can be used in the evaluation and comparison of body conformation in buffaloes and thus provides an opportunity to distinguish between early and late maturing to adult, based on a small group of biometric traits to explain body conformation in adult buffaloes. PMID:25656215

  14. Polarization in Raman spectroscopy helps explain bone brittleness in genetic mouse models

    Science.gov (United States)

    Makowski, Alexander J.; Pence, Isaac J.; Uppuganti, Sasidhar; Zein-Sabatto, Ahbid; Huszagh, Meredith C.; Mahadevan-Jansen, Anita; Nyman, Jeffry S.

    2014-11-01

    Raman spectroscopy (RS) has been extensively used to characterize bone composition. However, the link between bone biomechanics and RS measures is not well established. Here, we leveraged the sensitivity of RS polarization to organization, thereby assessing whether RS can explain differences in bone toughness in genetic mouse models for which traditional RS peak ratios are not informative. In the selected mutant mice-activating transcription factor 4 (ATF4) or matrix metalloproteinase 9 (MMP9) knock-outs-toughness is reduced but differences in bone strength do not exist between knock-out and corresponding wild-type controls. To incorporate differences in the RS of bone occurring at peak shoulders, a multivariate approach was used. Full spectrum principal components analysis of two paired, orthogonal bone orientations (relative to laser polarization) improved genotype classification and correlation to bone toughness when compared to traditional peak ratios. When applied to femurs from wild-type mice at 8 and 20 weeks of age, the principal components of orthogonal bone orientations improved age classification but not the explanation of the maturation-related increase in strength. Overall, increasing polarization information by collecting spectra from two bone orientations improves the ability of multivariate RS to explain variance in bone toughness, likely due to polarization sensitivity to organizational changes in both mineral and collagen.

  15. Can individual health differences be explained by workplace characteristics?--A multilevel analysis.

    Science.gov (United States)

    Marklund, Staffan; Bolin, Malin; von Essen, Jan

    2008-02-01

    Research on work-related health has mainly focused on individual factors. The present study expands the focus by exploring the role of organizational characteristics of workplaces for different individual health outcomes. The aim of the study was to look at differences in relative effect of workplace variations on five health outcomes, and to explain those differences in health outcomes by organizational characteristics. The sample encompassed 90 workplaces in Sweden and about 4300 individuals employed within these workplaces. Measurement of the workplace characteristics was carried out independently of the measurement of the individual's working conditions and health. Organizational data were collected by interviews with local managers at participating workplaces, and individual data were obtained by means of a survey of the employees. The results showed that a significant proportion of the variance in sickness absence, work ability, general health, and musculoskeletal disorders was attributed to the workplace. Of eight tested organizational characteristics, customer adaptation, lean production, and performance control could explain some of this workplace variance. The results also showed that only one organizational effect remained significant when controlled for the individual confounder of age and gender. High customer adaptation is associated with higher sickness absence. This association is not mediated via differences in mental and physical job strain.

  16. Usefulness of the CAD System for Detecting Pulmonary Nodule in Real Clinical Practice

    International Nuclear Information System (INIS)

    Song, Kyoung Doo; Chung, Myung Jin; Kim, Hee Cheol; Lee, Kyung Soo; Jeong, Sun Young

    2011-01-01

    We wanted to evaluate the usefulness of the computer-aided detection (CAD) system for detecting pulmonary nodules in real clinical practice by using the CT images. Our Institutional Review Board approved our retrospective study with a waiver of informed consent. This study included 166 CT examinations that were performed for the evaluation of pulmonary metastasis in 166 patients with colorectal cancer. All the CT examinations were interpreted by radiologists and they were also evaluated by the CAD system. All the nodules detected by the CAD system were evaluated with regard to whether or not they were true nodules, and they were classified into micro nodules (MN, diameter < 4 mm) and significant nodules (SN, 4 ≤ diameter ≤ 10 mm). The radiologic reports and CAD results were compared. The CAD system helped detect 426 nodules: 115 (27%) of the 426 nodules were classified as true nodules and 35 (30%) of the 115 nodules were SNs, and 83 (72%) of the 115 were not mentioned in the radiologists' reports and three (4%) of the 83 nodules were non-calcified SNs. One of three non-calcified SNs was confirmed as a metastatic nodule. According to the radiologists' reports, 60 true nodules were detected, and 28 of the 60 were not detected by the CAD system. Although the CAD system missed many SNs that are detected by radiologists, it helps detect additional nodules that are missed by the radiologists in real clinical practice. Therefore, the CAD system can be useful to support a radiologist's detection performance

  17. CT virtual intravascular endoscopy assessment of coronary artery plaques: A preliminary study

    International Nuclear Information System (INIS)

    Sun Zhonghua; Dimpudus, Franky Jacobus; Nugroho, Johanes; Adipranoto, Jeffrey Daniel

    2010-01-01

    Purpose: The purpose of this study was to investigate the potential value of CT virtual intravascular endoscopy (VIE) in the visualization and assessment of coronary plaques in patients suspected of coronary artery disease. Materials and methods: 20 (13 men, 7 women, mean age 54 years) consecutive patients with suspected coronary artery disease undergoing 64-slice CT angiography were included in the study. Four main coronary artery branches were assessed with regard to the presence of coronary plaques based on 2D axial, multiplanar reformation, 3D volume rendering and VIE visualizations. The coronary plaques were characterized into calcified, noncalcified and mixed plaques. The intraluminal appearances of these coronary plaques were demonstrated with VIE images and correlated with 2D and 3D images to determine the diagnostic value of VIE for the assessment of the plaques. Results: VIE was able to identify and demonstrate the intraluminal appearances of coronary plaques in 18 patients involving 32 coronary artery branches which were shown as an irregularly intraluminal protruding sign in extensively calcified plaques and smooth protruding appearance in noncalcified or focally calcified plaques. An irregular intraluminal appearance was also noticed in the presence of mixed plaques due to variable components with different CT attenuations contained within the plaques. VIE accurately confirmed the degree of coronary stenosis or occlusion despite the presence of heavy calcification. Conclusion: VIE could be used as a complementary tool to conventional CT visualizations for the analysis of luminal changes and assessment of disease extent caused by the coronary plaques.

  18. Comparison of multislice computed tomography with intravascular ultrasound for detection and characterization of coronary artery plaques: A systematic review

    Energy Technology Data Exchange (ETDEWEB)

    Springer, Ivonne [Department of Radiology, Charite, Medical School, Humboldt-Universitaet zu Berlin (Germany); Dewey, Marc [Department of Radiology, Charite, Medical School, Humboldt-Universitaet zu Berlin (Germany)], E-mail: marc.dewey@charite.de

    2009-08-15

    Purpose: Multislice computed tomography (MSCT) is a novel non-invasive test for detection and analysis of coronary artery plaques. A systematic review was conducted of the literature to compare MSCT with IVUS as the reference standard for assessing coronary artery plaques. Materials and methods: We performed a literature search in the online database MEDLINE, which was accessed at (http://www.pubmed.gov) on 9th April 2008. Results: The search identified 14 studies with 340 patients (mean age 59 {+-} 5 years). The systematic review revealed a sensitivity of MSCT on the lesion level (n = 1779 coronary plaques) on the order of 90% (range from 87 to 92%) in comparison to IVUS. Per-segment analysis (n = 356) yielded a lower sensitivity of 81-86%. In the per-vessel analysis (n = 90), MSCT had a better sensitivity and specificity for the RCA (83-89% and 92-100%) and the LAD (83-87% and 93%) than for the LCX (71-85% and 77-89%), and on the vessel level and the cross-section analysis MSCT was more sensitive for calcified plaques than for non-calcified plaque. It is noteworthy that most studies provide only incomplete data on technical and methodological parameters such as radiation exposure and patient characteristics. Conclusion: MSCT is an accurate and reliable test for detection of coronary artery plaques in comparison to IVUS with limitations in regards to the LCX and non-calcified plaques. Studies published thus far are limited by the sample sizes and methodological quality issues.

  19. Evaluation of the early enhancement of coronary atherosclerotic plaque by contrast-enhanced MR angiography

    Energy Technology Data Exchange (ETDEWEB)

    Li Tao [Department of Radiology, The General Hospital of Chinese People' s Armed Police Forces, Number 69, Yong Ding Road, Hai Dian District, Beijing (China); Department of Radiology, Chinese People' s Liberation Army General Hospital, Number 28, Fu Xing Road, Hai Dian District, Beijing (China); Zhao Xihai [Department of Radiology, Chinese People' s Liberation Army General Hospital, Number 28, Fu Xing Road, Hai Dian District, Beijing (China); Liu Xin [Paul C. Lauterbur Biomedical Imaging Center, Institute of Biomedical and Health Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Science, Shenzhen 518067 (China); Gao Jianhua [Department of Radiology, The General Hospital of Chinese People' s Armed Police Forces, Number 69, Yong Ding Road, Hai Dian District, Beijing (China); Zhao Shaohong [Department of Radiology, Chinese People' s Liberation Army General Hospital, Number 28, Fu Xing Road, Hai Dian District, Beijing (China); Li Xin; Zhou Weihua [Department of Radiology, The General Hospital of Chinese People' s Armed Police Forces, Number 69, Yong Ding Road, Hai Dian District, Beijing (China); Cai Zulong [Department of Radiology, Chinese People' s Liberation Army General Hospital, Number 28, Fu Xing Road, Hai Dian District, Beijing (China); Zhang Weiguo [Cardiovascular and Neurological Consulting Institute, 6771 San Fernando, Irving, TX 75039 (United States); Yang Li, E-mail: Yangli301@yahoo.com [Department of Radiology, Chinese People' s Liberation Army General Hospital, Number 28, Fu Xing Road, Hai Dian District, Beijing (China)

    2011-10-15

    Purpose: To evaluate the early enhancement of coronary atherosclerotic plaque using contrast-enhanced MR angiography (CE-MRA) and investigate the association between unstable angina pectoris (UAP) and early enhancement of the plaque. Methods: Forty-one patients presenting with angina pectoris and demonstrating single-vessel disease with non-calcified plaque and significant coronary stenosis ({>=}50%) on CTA were consecutively recruited for coronary CE-MRA. Contrast-to-noise ratio of the culprit plaque guided by CTA was measured on a cross-sectional multi-planar reconstruction image of the plaque on both pre- and post-CE-MRA. A 50% increasing of CNR was defined as plaque enhancement. The association between early enhancement of the plaques and UAP was analyzed. Results: Thirty-seven non-calcified plaques with significant coronary stenosis were detected in the 37 patients on MRA. 4 subjects were excluded because coronary atherosclerotic plaques were inadequate for identification on MRA. Of the 37 patients, 18 patients had UAP and other 19 patients presented stable angina pectoris (SAP). Of the 37 plaques on CE-MRA, 13 and 24 plaques presented early enhancement and no enhancement, respectively. Of the 13 early-enhanced plaques, 11 (85%) and 2 (15%) were found in the patients with UAP and SAP, respectively (p < 0.01). Of the 37 patients, 11 (61%) with UAP and 2 (11%) with SAP had early-enhanced plaques, respectively (p < 0.01). Conclusion: CE-MRA allows detection of early enhancement of coronary atherosclerotic plaque. The early enhancement is common in unstable angina and could be a sign of vulnerability.

  20. The internal-brooding apparatus in the bryozoan genus Cauloramphus (Cheilostomata: Calloporidae) and its inferred homology to ovicells.

    Science.gov (United States)

    Ostrovsky, Andrew N; Dick, Matthew H; Mawatari, Shunsuke F

    2007-12-01

    We studied by SEM the external morphology of the ooecium in eight bryozoans of the genus Cauloramphus (Cheilostomata, Calloporidae): C. spinifer, C. variegatus, C. magnus, C. multiavicularia, C. tortilis, C. cryptoarmatus, C. niger, and C. multispinosus, and by sectioning and light microscopy the anatomy of the brooding apparatus of C. spinifer, C. cryptoarmatus, and C. niger. These species all have a brood sac, formed by invagination of the non-calcified distal body wall of the maternal zooid, located in the distal half of the maternal (egg-producing) autozooid, and a vestigial, maternally budded kenozooidal ooecium. The brood sac comprises a main chamber and a long passage (neck) opening externally independently of the introvert. The non-calcified portion of the maternal distal wall between the neck and tip of the zooidal operculum is involved in closing and opening the brood sac, and contains both musculature and a reduced sclerite that suggest homology with the ooecial vesicle of a hyperstomial ovicell. We interpret the brooding apparatus in Cauloramphus as a highly modified form of cheilostome hyperstomial ovicell, as both types share 1) a brood chamber bounded by 2) the ooecium and 3) a component of the distal wall of the maternal zooid. We discuss Cauloramphus as a hypothetical penultimate stage in ovicell reduction in calloporid bryozoans. We suggest that the internal-brooding genus Gontarella, of uncertain taxonomic affinities, is actually a calloporid and represents the ultimate stage in which no trace of the ooecium remains. Internal brooding apparently evolved several times independently within the Calloporidae.

  1. Explaining Compound Generalization in Associative and Causal Learning Through Rational Principles of Dimensional Generalization

    Science.gov (United States)

    Soto, Fabian A.; Gershman, Samuel J.; Niv, Yael

    2014-01-01

    How do we apply learning from one situation to a similar, but not identical, situation? The principles governing the extent to which animals and humans generalize what they have learned about certain stimuli to novel compounds containing those stimuli vary depending on a number of factors. Perhaps the best studied among these factors is the type of stimuli used to generate compounds. One prominent hypothesis is that different generalization principles apply depending on whether the stimuli in a compound are similar or dissimilar to each other. However, the results of many experiments cannot be explained by this hypothesis. Here we propose a rational Bayesian theory of compound generalization that uses the notion of consequential regions, first developed in the context of rational theories of multidimensional generalization, to explain the effects of stimulus factors on compound generalization. The model explains a large number of results from the compound generalization literature, including the influence of stimulus modality and spatial contiguity on the summation effect, the lack of influence of stimulus factors on summation with a recovered inhibitor, the effect of spatial position of stimuli on the blocking effect, the asymmetrical generalization decrement in overshadowing and external inhibition, and the conditions leading to a reliable external inhibition effect. By integrating rational theories of compound and dimensional generalization, our model provides the first comprehensive computational account of the effects of stimulus factors on compound generalization, including spatial and temporal contiguity between components, which have posed longstanding problems for rational theories of associative and causal learning. PMID:25090430

  2. Explain the 'unexplainable': A qualitative enquiry of the representations of the caregivers of brain-injured people.

    Science.gov (United States)

    Huet, Magali; Dany, Lionel; Apostolidis, Thémistoklis

    2016-04-01

    The aim of our research is to highlight the role of social representations of the traumatic brain-injured person in the adjustments made by caregivers in building and maintaining quality of care. Twenty-three semi-structured interviews were conducted with nursing assistants and medico-psychological assistants, working in a long-term care facility. The interviews were the subject of a thematic content analysis. The analysis shows the role of representations of the traumatic brain-injured person in the way caregivers explain behaviours and situations and in the orientation of their professional practices. In explaining the inexplicable, caregivers establish a more human relationship through individualized care.

  3. Sermons, Carrots or Sticks? Explaining Successful Policy Implementation in a Low Performance Institution

    Science.gov (United States)

    Salazar-Morales, Diego Alonso

    2018-01-01

    This article explains how after 43 years of unsatisfactory outcomes, the Ministry of Education of Peru (MoE) suddenly ranked at the top of governmental performance tables. To do so, this study relies on implementation and major discussions of policy instrument theories to provide a comprehensive explanation of the reasons underlying the MoE's…

  4. Explaining the paradox : How pro-environmental behaviour can both thwart and foster well-being

    NARCIS (Netherlands)

    Venhoeven, Leonie; Bolderdijk, Jan Willem; Steg, Linda

    Although pro-environmental behaviour is often believed to be difficult, aggravating, and potentially threatening one's quality of life, recent studies suggest that people who behave in a more pro-environmental way are actually more satisfied with their lives. In this manuscript, we aim to explain

  5. Explaining the energy efficiency gap - expected utility theory versus cumulative prospect theory

    OpenAIRE

    Häckel, Björn; Pfosser, Stefan; Tränkler, Timm

    2017-01-01

    Energy efficiency is one of the key factors in mitigating the impact of climate change and preserving non-renewable resources. Although environmental and economic justifications for energy efficiency investments are compelling, there is a gap between the observable and some notion of optimized energy consumption - the so-called energy efficiency gap. Behavioral biases in individual decision making have been resonated by environmental research to explain this gap. To analyze the influence of b...

  6. What explains between-school differences in rates of sexual experience?

    Directory of Open Access Journals (Sweden)

    Williamson Lisa

    2008-02-01

    Full Text Available Abstract Background Schools have the potential to influence their pupils' behaviour through the school's social organisation and culture, as well as through the formal curriculum. This paper provides the first attempt to explain the differences between schools in rates of reported heterosexual sexual experience amongst 15 and 16 year olds. It first examined whether variations in rates of sexual experience remained after controlling for the known predictors of sexual activity. It then examined whether these residuals, or 'school effects', were attributable to processes within the school, or were more likely to reflect characteristics of the neighbourhood. Methods Longitudinal survey data from 4,926 pupils in 24 Scottish schools were linked to qualitative and quantitative data on school processes including quality of relationships (staff-pupil, etc, classroom discipline, organisation of Personal and Social Education, school appearance and pupil morale. Multi-level modelling was used to test a range of models and the resulting 'school effects' were then interpreted using the process data. Results Overall, 42% of girls and 33% of boys reported experience of sexual intercourse, with rates by school ranging from 23% to 61%. When individual socio-economic and socio-cultural factors were taken into account the school variation dropped sharply, though pupils' attitudes and aspirations had little effect. There was very little correlation between boys' and girls' rates of sexual experience by school, after controlling for known predictors of sexual activity. Girls were more influenced by individual socio-economic factors than boys. School-level socio-economic factors were predictive even after taking account of individual socio-cultural factors, suggesting that the wider socio-economic environment further influenced young people's sexual experience. Conclusion Importantly, school processes did not explain the variation between schools in sexual experience

  7. Explaining History. Hippolyte Taine's Philosophy of Historical Science

    Science.gov (United States)

    Müller, Philipp

    Historians of European historiography have often characterized Hippolyte Taine (1828-1893) as an adherent of the positivist school of thought, typical for the development of a scientific culture in Western Europe that differed from its German counterpart.1 In accordance with that view, Wilhelm Dilthey grouped him together with other scholars like John Stuart Mill and Herbert Spencer against who Dilthey tried to develop his conception of the human sciences based on the notion of "verstehen" (see Dilthey [1924] 1957, 139ff.). Dilthey understood Taine as proposing to analyze the human mind by identifying its individual components and then explaining their meaning by laws of their relation. He argued that such an approach might be adequate for the natural sciences, but neglected the fact that an analysis of the mind had to start from a given psychological connection that was prior to any definition of particular phenomena. From Dilthey's point of view, applying Taine's theory to historical studies only made them look more objective while actually Taine was unaware of just following the prevailing convictions of his time (idem, 191f.).

  8. Can Strategic Ignorance Explain the Evolution of Love?

    Science.gov (United States)

    Bear, Adam; Rand, David G

    2018-04-24

    People's devotion to, and love for, their romantic partners poses an evolutionary puzzle: Why is it better to stop your search for other partners once you enter a serious relationship when you could continue to search for somebody better? A recent formal model based on "strategic ignorance" suggests that such behavior can be adaptive and favored by natural selection, so long as you can signal your unwillingness to "look" for other potential mates to your current partner. Here, we re-examine this conclusion with a more detailed model designed to capture specific features of romantic relationships. We find, surprisingly, that devotion does not typically evolve in our model: Selection favors agents who choose to "look" while in relationships and who allow their partners to do the same. Non-looking is only expected to evolve if there is an extremely large cost associated with being left by your partner. Our results therefore raise questions about the role of strategic ignorance in explaining the evolution of love. Copyright © 2018 Cognitive Science Society, Inc.

  9. Translucent Players: Explaining Cooperative Behavior in Social Dilemmas

    Directory of Open Access Journals (Sweden)

    Valerio Capraro

    2016-06-01

    Full Text Available In the last few decades, numerous experiments have shown that humans do not always behave so as to maximize their material payoff. Cooperative behavior when non-cooperation is a dominant strategy (with respect to the material payoffs is particularly puzzling. Here we propose a novel approach to explain cooperation, assuming what Halpern and Pass call translucent players. Typically, players are assumed to be opaque, in the sense that a deviation by one player in a normal-form game does not affect the strategies used by other players. But a player may believe that if he switches from one strategy to another, the fact that he chooses to switch may be visible to the other players. For example, if he chooses to defect in Prisoner's Dilemma, the other player may sense his guilt. We show that by assuming translucent players, we can recover many of the regularities observed in human behavior in well-studied games such as Prisoner's Dilemma, Traveler's Dilemma, Bertrand Competition, and the Public Goods game.

  10. Sexual selection on land snail shell ornamentation: a hypothesis that may explain shell diversity

    NARCIS (Netherlands)

    Schilthuizen, M.

    2003-01-01

    Background: Many groups of land snails show great interspecific diversity in shell ornamentation, which may include spines on the shell and flanges on the aperture. Such structures have been explained as camouflage or defence, but the possibility that they might be under sexual selection has not

  11. The Roles of Cognitive and Motivational Predictors in Explaining School Achievement in Elementary School

    Science.gov (United States)

    Weber, Heike S.; Lu, Liping; Shi, Jiannong; Spinath, Frank M.

    2013-01-01

    The present study investigated the roles of cognitive (working memory, intelligence) and motivational variables (self-perceived ability, intrinsic value) in explaining school achievement. The sample consisted of N = 320 German elementary school children in the fourth grade. Working memory and intelligence were assessed in the classroom.…

  12. Explaining the Effectiveness of the Contrast Culture Method for Managing Interpersonal Interactions across Cultures

    Science.gov (United States)

    Hiratsuka, Hiroyoshi; Suzuki, Hanako; Pusina, Alexis

    2016-01-01

    One of the current challenges in the field of intercultural education comes from the limited availability of training efficacy studies. The present study focused on explaining the effectiveness of the Contrast Culture Method (CCM) as an intercultural education method for managing interpersonal interactions across cultures between graduate…

  13. Indirect Evolution Versus Strategic Delegation : A Comparison of Two Approaches to Explaining Economic Institutions

    NARCIS (Netherlands)

    Dufwenberg, M.; Güth, W.

    1997-01-01

    The two major methods of explaining economic institutions, namely by strategic choices or by (indirect) evolution, are compared for the case of a homogenous quadratic duopoly market. Sellers either can provide incentives for their agents to care for sales (amounts) or evolve as sellers who care for

  14. Competition explains limited attention and perceptual resources: implications for perceptual load and dilution theories

    Directory of Open Access Journals (Sweden)

    Paige E. Scalf

    2013-05-01

    Full Text Available Both perceptual load theory and dilution theory purport to explain when and why task-irrelevant information, or so-called distractors are processed. Central to both explanations is the notion of limited resources, although the theories differ in the precise way in which those limitations affect distractor processing. We have recently proposed a neurally plausible explanation of limited resources in which neural competition among stimuli hinders their representation in the brain. This view of limited capacity can also explain distractor processing, whereby the competitive interactions and bias imposed to resolve the competition determine the extent to which a distractor is processed. This idea is compatible with aspects of both perceptual load and dilution models of distractor processing, but also serves to highlight their differences. Here we review the evidence in favor of a biased competition view of limited resources and relate these ideas to both classic perceptual load theory and dilution theory.

  15. Can genetically based clines in plant defence explain greater herbivory at higher latitudes?

    Science.gov (United States)

    Anstett, Daniel N; Ahern, Jeffrey R; Glinos, Julia; Nawar, Nabanita; Salminen, Juha-Pekka; Johnson, Marc T J

    2015-12-01

    Greater plant defence is predicted to evolve at lower latitudes in response to increased herbivore pressure. However, recent studies question the generality of this pattern. In this study, we tested for genetically based latitudinal clines in resistance to herbivores and underlying defence traits of Oenothera biennis. We grew plants from 137 populations from across the entire native range of O. biennis. Populations from lower latitudes showed greater resistance to multiple specialist and generalist herbivores. These patterns were associated with an increase in total phenolics at lower latitudes. A significant proportion of the phenolics were driven by the concentrations of two major ellagitannins, which exhibited opposing latitudinal clines. Our analyses suggest that these findings are unlikely to be explained by local adaptation of herbivore populations or genetic variation in phenology. Rather greater herbivory at high latitudes can be explained by latitudinal clines in the evolution of plant defences. © 2015 John Wiley & Sons Ltd/CNRS.

  16. Les microbialites de l'Anti-Atlas occidental (Maroc) : marqueurs stratigraphiques et témoins des changements environnementaux au Cambrien inférieur Stratigraphic and environmental significance of the Lower-Cambrian western Anti-Atlasic microbialites (Morocco)

    Science.gov (United States)

    Benssaou, Mohammed; Hamoumi, Naima

    2004-02-01

    Three microbialite forms are recognized in the Lower-Cambrian succession of Irherm area in the western Anti-Atlas (Morocco). Stromatolites, which correspond to non-calcified shallow marine laminated microbialites, are well developed in the basal Lower-Cambrian succession. Occurrence of calcified microbial thrombolites, in the middle part of this succession, reflects an increasing sea level from the peritidal zone to the subtidal environment. In the upper part of this succession, a second increasing water depth event and the development of branching archaeocyathan reefal framework lead to dendritic microbialite emergence. To cite this article: M. Benssaou, N. Hamoumi, C. R. Geoscience 336 (2004).

  17. Anticipation of dental anomalies induced by radiation therapy

    International Nuclear Information System (INIS)

    Guggenheimer, J.; Fischer, W.G.; Pechersky, J.L.

    1975-01-01

    Therapeutic irradiation of the head and neck of children up to the age of 16 years can cause malformation and developmental arrest of the permanent teeth. Dental anomalies occurring after irradiation of the palatal tumor in an 8-year-old are described and compared with a normal 8-year-old's developmental sequence to demonstrate that the immature, noncalcified dental structures are most susceptible to radiation injury. The stage of dental development at the time of therapy may be precisely determined by a routine oral radiographic survey, which provides a reliable estimate of the deformation that may be anticipated following radiotherapy. (auth)

  18. CAN LARGE TIME DELAYS OBSERVED IN LIGHT CURVES OF CORONAL LOOPS BE EXPLAINED IN IMPULSIVE HEATING?

    International Nuclear Information System (INIS)

    Lionello, Roberto; Linker, Jon A.; Mikić, Zoran; Alexander, Caroline E.; Winebarger, Amy R.

    2016-01-01

    The light curves of solar coronal loops often peak first in channels associated with higher temperatures and then in those associated with lower temperatures. The delay times between the different narrowband EUV channels have been measured for many individual loops and recently for every pixel of an active region observation. The time delays between channels for an active region exhibit a wide range of values. The maximum time delay in each channel pair can be quite large, i.e., >5000 s. These large time delays make-up 3%–26% (depending on the channel pair) of the pixels where a trustworthy, positive time delay is measured. It has been suggested that these time delays can be explained by simple impulsive heating, i.e., a short burst of energy that heats the plasma to a high temperature, after which the plasma is allowed to cool through radiation and conduction back to its original state. In this paper, we investigate whether the largest observed time delays can be explained by this hypothesis by simulating a series of coronal loops with different heating rates, loop lengths, abundances, and geometries to determine the range of expected time delays between a set of four EUV channels. We find that impulsive heating cannot address the largest time delays observed in two of the channel pairs and that the majority of the large time delays can only be explained by long, expanding loops with photospheric abundances. Additional observations may rule out these simulations as an explanation for the long time delays. We suggest that either the time delays found in this manner may not be representative of real loop evolution, or that the impulsive heating and cooling scenario may be too simple to explain the observations, and other potential heating scenarios must be explored

  19. Explaining G20 and BRICS Compliance

    Directory of Open Access Journals (Sweden)

    Marina Larionova

    2016-11-01

    Full Text Available This article explores the internal and external factors influencing the compliance performance of the Group of 20 (G20 and the BRICS. The authors start with an overview of the G20 and BRICS compliance patterns using comparative data onthe number of commitments made by the two institutions, the level of institutional compliance, and distribution of commitments and compliance across issue areas. G20 compliance is traced since the leaders’ first 2008 summit in Washington. The BRICS compliance performance record includes data since the third stand alone summit in Sanya in 2011.The study then takes stock of compliance catalysts embedded in the summits’ discourse: priority placements, numerical targets, timelines, self-accountability pledges and mandates to implement and/or monitor implementation. The authors review trends in the use of catalysts in different years and issue areas and identify commonalities and differences.The analysis then turns to external causes of compliance and focuses on demand for collective actions and members’ collective power to respond and deliver on their pledges. Here the study explores whether the self-accountability mechanisms created by the institutions in response to the demand for effectiveness and legitimacy facilitate compliance.The article concludes by highlighting catalysts, causes of compliance and their combinations with the greatest power to encourage implementation, explaining trends in G20 and BRICS compliance performance. The data sets on G20 and BRICS differ in terms of scale. The G20 data set contains 1,511 commitments of which 114 have been monitored, and the BRICS data set contains 231 commitments of which 23 have been monitored.

  20. Indole-3-Acetic Acid Is Produced by Emiliania huxleyi Coccolith-Bearing Cells and Triggers a Physiological Response in Bald Cells.

    Science.gov (United States)

    Labeeuw, Leen; Khey, Joleen; Bramucci, Anna R; Atwal, Harjot; de la Mata, A Paulina; Harynuk, James; Case, Rebecca J

    2016-01-01

    Indole-3-acetic acid (IAA) is an auxin produced by terrestrial plants which influences development through a variety of cellular mechanisms, such as altering cell orientation, organ development, fertility, and cell elongation. IAA is also produced by bacterial pathogens and symbionts of plants and algae, allowing them to manipulate growth and development of their host. They do so by either producing excess exogenous IAA or hijacking the IAA biosynthesis pathway of their host. The endogenous production of IAA by algae remains contentious. Using Emiliania huxleyi, a globally abundant marine haptophyte, we investigated the presence and potential role of IAA in algae. Homologs of genes involved in several tryptophan-dependent IAA biosynthesis pathways were identified in E. huxleyi. This suggests that this haptophyte can synthesize IAA using various precursors derived from tryptophan. Addition of L-tryptophan to E. huxleyi stimulated IAA production, which could be detected using Salkowski's reagent and GC × GC-TOFMS in the C cell type (coccolith bearing), but not in the N cell type (bald). Various concentrations of IAA were exogenously added to these two cell types to identify a physiological response in E. huxleyi. The N cell type, which did not produce IAA, was more sensitive to it, showing an increased variation in cell size, membrane permeability, and a corresponding increase in the photosynthetic potential quantum yield of Photosystem II (PSII). A roseobacter (bacteria commonly associated with E. huxleyi) Ruegeria sp. R11, previously shown to produce IAA, was co-cultured with E. huxleyi C and N cells. IAA could not be detected from these co-cultures, and even when stimulated by addition of L-tryptophan, they produced less IAA than axenic C type culture similarly induced. This suggests that IAA plays a novel role signaling between different E. huxleyi cell types, rather than between a bacteria and its algal host.