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Sample records for explain observed crista

  1. Mitochondrial cristae revealed with focused light.

    OpenAIRE

    Schmidt, R.; Wurm, C.; Punge, A.; Egner, A.; Jakobs, S.; Hell, S.

    2009-01-01

    Because of the diffraction resolution barrier, optical microscopes have so far failed in visualizing the mitochondrial cristae, that is, the folds of the inner membrane of this 200 to 400 nm diameter sized tubular organelle. Realizing a ∼30 nm isotropic subdiffraction resolution in isoSTED fluorescence nanoscopy, we have visualized these essential structures in the mitochondria of intact cells. We find a pronounced heterogeneity in the cristae arrangements even within individual mitochondrial...

  2. Mitochondrial cristae revealed with focused light.

    Science.gov (United States)

    Schmidt, Roman; Wurm, Christian A; Punge, Annedore; Egner, Alexander; Jakobs, Stefan; Hell, Stefan W

    2009-06-01

    Because of the diffraction resolution barrier, optical microscopes have so far failed in visualizing the mitochondrial cristae, that is, the folds of the inner membrane of this 200 to 400 nm diameter sized tubular organelle. Realizing a approximately 30 nm isotropic subdiffraction resolution in isoSTED fluorescence nanoscopy, we have visualized these essential structures in the mitochondria of intact cells. We find a pronounced heterogeneity in the cristae arrangements even within individual mitochondrial tubules.

  3. Mitofilin and CHCHD6 physically interact with Sam50 to sustain cristae structure.

    Science.gov (United States)

    Ding, Chengli; Wu, Zhifei; Huang, Lei; Wang, Yajie; Xue, Jie; Chen, Si; Deng, Zixin; Wang, Lianrong; Song, Zhiyin; Chen, Shi

    2015-11-04

    The inner mitochondrial membrane (IMM) invaginates to form cristae and the maintenance of cristae depends on the mitochondrial contact site (MICOS) complex. Mitofilin and CHCHD6, which physically interact, are two components of the MICOS. In this study, we performed immunoprecipitation experiments with Mitofilin and CHCHD6 antibodies and identified a complex containing Mitofilin, Sam50, and CHCHD 3 and 6. Using transcription activator-like effector nucleases (TALENs), we generated knockdown/knockout clones of Mitofilin and CHCHD6. Transmission electron microscopy (TEM) revealed that vesicle-like cristae morphology appeared in cell lines lacking Mitofilin, and mitochondria exhibited lower cristae density in CHCHD6-knockout cells. Immunoblot analysis showed that knockdown of Mitofilin, but not knockout of CHCHD6, affected their binding partners that control cristae morphology. We also demonstrated that Mitofilin and CHCHD6 directly interacted with Sam50. Additionally, we observed that Mitofilin-knockdown cells showed decreased mitochondrial membrane potential (ΔΨm) and intracellular ATP content, which were minimally affected in CHCHD6-knockout cells. Taken together, we conclude that the integrity of MICOS and its efficient interaction with Sam50 are indispensable for cristae organization, which is relevant to mitochondrial function.

  4. The relationship between the distal metatarsal articular angle and intersesamoidal crista: An osteological study.

    Science.gov (United States)

    Maddocks, Megan; Nalla, Shahed; Zipfel, Bernhard

    2017-03-01

    As hallux valgus (HV) progresses, the first metatarsal drifts medially and the subsequent lateral drift of the sesamoids results in intersesamoidal crista erosion. This study aimed to provide a novel method of assessing crista erosion and determine if there is a relationship between that erosion and an increase in the distal metatarsal articular angle (DMAA). The DMAA and size of the intersesamoidal crista was measured on the first metatarsals of 120 adult modern human individuals. There was an equitable spread of both sexes, a wide age range (18-88 years), from three South African population groups (Zulu, Sotho, "European"). The following non-metric features were observed: intersesamoidal crista appearance, metatarsal head shape, and first intermetatarsal facet. Correlation tests, t-tests and Analyses of Variance (ANOVA) were used to determine relationships between variables. The Pearson correlation test showed no significant correlation between the DMAA and crista ratio (r=0.092, p=0.154, α=0.05). DMAA: there was a significant difference between sides (p=0.009), right side larger; there was a significant difference between Zulu and "European" samples (p=0.036) but not between "Europeans" and Sotho (p=0.270); and there was a slight positive correlation with an increase in age. Crista: there was a significant difference between the sexes (p=0.044), with females having less erosion. There is no significant relationship between the DMAA and crista erosion. Severe cartilaginous erosion is present before osteological changes occur, and the unexpected result may be reflected in skeletal specimens in which no cartilaginous changes can be observed. A novel, experimental method of assessing HV in modern human skeletal material is proposed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Prominent crista terminalis mimicking a right atrial mass: case report

    Directory of Open Access Journals (Sweden)

    Lange Peter

    2010-10-01

    Full Text Available Abstract The crista terminalis is a normal anatomical structure within the right atrium that is not normally visualised in the standard views obtained while performing a transthoracic echocardiogram. In this case report, transthoracic echocardiography suggested the presence of a right atrial mass in a patient with end stage renal disease. However, subsequent transesophageal echocardiography revealed that the right atrial mass was actually a thick muscular bridge in the right atrium consistent with a prominent crista terminalis. An understanding of the anatomy and the echocardiographic appearance of a prominent crista terminalis will minimize the misdiagnosis of this structure avoiding unnecessary expensive additional tests.

  6. Life stage, not climate change, explains observed tree range shifts.

    Science.gov (United States)

    Máliš, František; Kopecký, Martin; Petřík, Petr; Vladovič, Jozef; Merganič, Ján; Vida, Tomáš

    2016-05-01

    Ongoing climate change is expected to shift tree species distribution and therefore affect forest biodiversity and ecosystem services. To assess and project tree distributional shifts, researchers may compare the distribution of juvenile and adult trees under the assumption that differences between tree life stages reflect distributional shifts triggered by climate change. However, the distribution of tree life stages could differ within the lifespan of trees, therefore, we hypothesize that currently observed distributional differences could represent shifts over ontogeny as opposed to climatically driven changes. Here, we test this hypothesis with data from 1435 plots resurveyed after more than three decades across the Western Carpathians. We compared seedling, sapling and adult distribution of 12 tree species along elevation, temperature and precipitation gradients. We analyzed (i) temporal shifts between the surveys and (ii) distributional differences between tree life stages within both surveys. Despite climate warming, tree species distribution of any life stage did not shift directionally upward along elevation between the surveys. Temporal elevational shifts were species specific and an order of magnitude lower than differences among tree life stages within the surveys. Our results show that the observed range shifts among tree life stages are more consistent with ontogenetic differences in the species' environmental requirements than with responses to recent climate change. The distribution of seedlings substantially differed from saplings and adults, while the distribution of saplings did not differ from adults, indicating a critical transition between seedling and sapling tree life stages. Future research has to take ontogenetic differences among life stages into account as we found that distributional differences recently observed worldwide may not reflect climate change but rather the different environmental requirements of tree life stages. © 2016

  7. Phytodegradation potential of Erythrina crista-galli L., Fabaceae, in petroleum-contaminated soil.

    Science.gov (United States)

    de Farias, Vanessa; Maranho, Leila Teresinha; de Vasconcelos, Eliane Carvalho; da Silva Carvalho Filho, Marco Aurélio; Lacerda, Luiz Gustavo; Azevedo, Jayme Augusto Menegassi; Pandey, Ashok; Soccol, Carlos Ricardo

    2009-04-01

    This work aimed at investigating both the tolerance and the phytodegradation potential of Erythrina crista-galli L. in petroleum-contaminated soil. It consisted in analyzing E. crista-galli germination, surviving, growth, and development when cultivated at different contaminant concentrations and pollutant degradation rates. This specimen was selected because it presented a special behavior among others also exposed to petroleum in an accident that occurred in the Araucaria region (south of Brazil), resulting in a four-million-liter oil spill. The experiment was carried out in a greenhouse containing non-contaminated soil (NCS), vegetated contaminated soil (VCS), and non-vegetated contaminated soil (NVCS) at the following petroleum concentrations: 25 g kg(-1) (VCS-25), 50 g kg(-1) (VCS-50), and 75 g kg(-1) (VCS-75). After 60 days, the soil samples were analyzed by gas chromatography. Germination was more and more evident as higher petroleum concentrations were observed. The surviving rates of groups NCS, VCS-25, VCS-50, and VCS-75 were 64%, 70%, 61%, and 96%, respectively. The VCS group growth was reduced when compared to the control group (NCS). The individuals exposed to petroleum pollution presented differences in the anatomic structure of their roots when compared to the NCS group. It was observed that the petroleum degradation rate was higher for VCS group than for NVCS. E. crista-galli is potentially recommended for petroleum-contaminated soils because of its positive association in the presence of contamination.

  8. The upper cretaceous snake Dinilysia patagonica Smith-Woodward, 1901, and the crista circumfenestralis of snakes.

    Science.gov (United States)

    Palci, Alessandro; Caldwell, Michael W

    2014-10-01

    Studies on the phylogenetic relationships of snakes and lizards are plagued by problematic characterizations of anatomy that are then used to define characters and states in taxon-character matrices. State assignments and character descriptions must be clear characterizations of observable anatomy and topological relationships if homologies are to be hypothesized. A supposed homology among snakes, not observed in lizards, is the presence of a crista circumfenestralis (CCF), a system of bony crests surrounding the fenestra ovalis and lateral aperture of the recessus scalae tympani. We note that there are some fossil and extant snakes that lack a CCF, and some extant lizards that possess a morphological equivalent. The phylogenetically important upper Cretaceous fossil snake Dinilysia patagonica has been interpreted by different authors as either having or lacking a CCF. These conflicting results for Dinilysia were tested by re-examining the morphology of the otic region in a large sample of snakes and lizards. An unambiguous criterion arising from the test of topology is used to define the presence of a CCF: the enclosure of the ventral margin of the juxtastapedial recess by flanges of the otoccipital (crista tuberalis and crista interfenestralis) that extend forward to contact the posterior margin of the prootic. According to this criterion D. patagonica does not possess a CCF, therefore, this anatomical feature must have arisen later during the evolution of snakes. Copyright © 2014 Wiley Periodicals, Inc.

  9. Plasticity in mitochondrial cristae density allows metabolic capacity modulation in human skeletal muscle

    DEFF Research Database (Denmark)

    Nielsen, Joachim; Gejl, Kasper D; Hey-Mogensen, Martin

    2017-01-01

    , in human skeletal muscle, contrary to the current view, the mitochondrial cristae density is not constant, but exhibits plasticity with long-term endurance training. Furthermore, we show that frequently recruited mitochondria-enriched fibres have significantly increased cristae density and that, at whole......Mitochondrial energy production involves the movement of protons down a large electrochemical gradient through ATP synthase located on the folded inner membrane, known as cristae. In mammalian skeletal muscle, the density of cristae in mitochondria is thought to be constant. However, recent......-body level, muscle mitochondrial cristae density is a better predictor of maximal oxygen uptake rate than muscle mitochondrial volume. Our findings establish elevating mitochondrial cristae density as a regulatory mechanism for increasing metabolic power in human skeletal muscle. We propose...

  10. Prominent crista terminalis mimicking a right atrial mixoma: cardiac magnetic resonance aspects.

    Science.gov (United States)

    Gaudio, C; Di Michele, S; Cera, M; Nguyen, B L; Pannarale, G; Alessandri, N

    2004-01-01

    A 68-year-old woman came to our observation with a clinical history of isolated systolic hypertension poorly controlled by the combination of ramipril 5 mg and hydrochlorothiazide 12.5 mg o.d. The ECG showed sinus rhythm with heart rate of 68 beats per minute and signs of left ventricular hypertrophy without strain. Further investigation included an echocardiogram that showed normal left and right cavities and normal cardiac valves. At the level of the posterior wall of the right atrial (RA) an apparent smooth, bean-like tumor, having a thin pedicle, was identified as a RA mixoma. Cardiac MRI was requested and showed in two sequential slices a muscular ridge, identified as a prominent crista terminalis. Some para-physiological structures sited in the RA may have the appearance of tumors, as crista terminalis, Eustachian valve extending into the RA chambers and Chiari network. The multiplain projections of MRI allow the cardiologist to identify the presence of intracardiac masses and to make a differential diagnosis between neoplasms and variant anatomic structures.

  11. Antibacterial and antifungal activities of the polyphenolic fractions isolated from the seed coat of Abrus precatorius and Caesalpinia crista.

    Science.gov (United States)

    Mobin, Lubna; Saeed, Syed Asad; Ali, Rashida; Saeed, Syed Ghufran; Ahmed, Rahil

    2017-09-26

    Crude seed coat extracts from Abrus precatorius and Caesalpinia crista were purified into four different fractions namely phenolic acids, flavonols, flavanols and anthocyanin which were then examined for their polyphenol contents and antimicrobial potentials. The fractions derived from seed coat of A. precatorius were found more potent with high phenolic and flavonoid contents as compared to C. crista fractions. The significant antibacterial activity was observed against all strain tested by the fractions of both samples apart from anthocyanin fraction. It was interesting to note that the phenolic acid fractions of both samples was found more active against gram-negative bacteria, while gram-positive bacteria were found to be more sensitive towards flavonol fractions. The phenolic acid and flavonol fractions being potent antibacterial were selected to demonstrate the antifungal capacity of two samples. Among them, phenolic acid fraction of both samples was found active towards all the fungal strain.

  12. MEMINIMALKAN MISKONSEPSI PADA MATERI RANGKAIAN LISTRIK DENGAN PEMBELAJARAN PREDICT-OBSERVE-EXPLAIN

    Directory of Open Access Journals (Sweden)

    Mursalin

    2014-09-01

    Full Text Available Abstract: Minimizing Misconceptions on the Topic of Electric Circuits by Predict-Observe-Explain Learning. This pretest-posttest control group experiment was aimed to improve students’ understanding of the concept and to minimize their misconceptions on the topic of electric circuits. The subjects were se­lected using cluster random sampling from high school students in Gorontalo. The instruments used to collect the data included pretest, posttest and questionnaires. The data were analyzed using t-test. The students' conception profiles were carried out using Certainty of Response Index (CRI technique. The results show the significant difference in the posttest average and normalized gain average between the experimental and the control classes. The results are supported by the fact that misconceptions in the experimental class are smaller than those in the control class. The application of predict-observe-explain learning is effective to improve the understanding of the concept and minimize the misconceptions. Keywords: Predict-Observe-Explain Learning, concept understandings, misconception, electric circuits Abstrak: Meminimalkan Miskonsepsi pada Materi Rangkaian Listrik dengan Pembelajaran Predict-Observe-Predict. Artikel hasil penelitian ini memaparkan mengenai upaya meningkatkan pemahaman konsep dan meminimalkan miskonsepsi pada materi rangkaian listrik dengan menggunakan model pem­belajaran Predict-Observe-Explain (POE. Penelitian dilakukan secara eksperimen dengan pretest-posttest control group design. Subyek penelitian ditentukan dengan teknik cluster random sampling dari siswa SMA kelas X suatu sekolah di Kota Gorontalo. Analisis data dilakukan dengan uji beda rerata gain ternormalisasi antara kelas eksperimen dan kelas kontrol, dan profil konsepsi siswa dianalisis dengan teknik Certainty of Response Index. Hasil penelitian mengungkap bahwa penerapan model pembelajaran POE efektif mening­katkan pemahaman konsep dan meminimalkan

  13. Applying a Predict-Observe-Explain Sequence in Teaching of Buoyant Force

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    Radovanovic, Jelena; Slisko, Josip

    2013-01-01

    An active learning sequence based on the predict-observe-explain teaching strategy is applied to a lesson on buoyant force. The results obtained clearly justify the use of this teaching method and suggest devising a series of activities to enable more effective removal of students' commonly held alternative conceptions regarding floating and…

  14. The relationship between observational scale and explained variance in benthic communities.

    Directory of Open Access Journals (Sweden)

    Alison M Flanagan

    Full Text Available This study addresses the impact of spatial scale on explaining variance in benthic communities. In particular, the analysis estimated the fraction of community variation that occurred at a spatial scale smaller than the sampling interval (i.e., the geographic distance between samples. This estimate is important because it sets a limit on the amount of community variation that can be explained based on the spatial configuration of a study area and sampling design. Six benthic data sets were examined that consisted of faunal abundances, common environmental variables (water depth, grain size, and surficial percent cover, and sonar backscatter treated as a habitat proxy (categorical acoustic provinces. Redundancy analysis was coupled with spatial variograms generated by multiscale ordination to quantify the explained and residual variance at different spatial scales and within and between acoustic provinces. The amount of community variation below the sampling interval of the surveys ( 71% of the remaining variance was explained by the environmental and province variables. Furthermore, these variables effectively explained the spatial structure present in the infaunal community. Overall, no scale problems remained to compromise inferences, and unexplained infaunal community variation had no apparent spatial structure within the observational scale of the surveys (> 100 m, although small-scale gradients (< 100 m below the observational scale may be present.

  15. The relationship between observational scale and explained variance in benthic communities.

    Science.gov (United States)

    Flanagan, Alison M; Flood, Roger D; Frisk, Michael G; Garza, Corey D; Lopez, Glenn R; Maher, Nicole P; Cerrato, Robert M

    2018-01-01

    This study addresses the impact of spatial scale on explaining variance in benthic communities. In particular, the analysis estimated the fraction of community variation that occurred at a spatial scale smaller than the sampling interval (i.e., the geographic distance between samples). This estimate is important because it sets a limit on the amount of community variation that can be explained based on the spatial configuration of a study area and sampling design. Six benthic data sets were examined that consisted of faunal abundances, common environmental variables (water depth, grain size, and surficial percent cover), and sonar backscatter treated as a habitat proxy (categorical acoustic provinces). Redundancy analysis was coupled with spatial variograms generated by multiscale ordination to quantify the explained and residual variance at different spatial scales and within and between acoustic provinces. The amount of community variation below the sampling interval of the surveys ( 71% of the remaining variance was explained by the environmental and province variables. Furthermore, these variables effectively explained the spatial structure present in the infaunal community. Overall, no scale problems remained to compromise inferences, and unexplained infaunal community variation had no apparent spatial structure within the observational scale of the surveys (> 100 m), although small-scale gradients (< 100 m) below the observational scale may be present.

  16. [The original method for the endonasal surgical access to the maxillary sinus through crista conchalis of the maxillary bone].

    Science.gov (United States)

    Tsarapkin, G Yu; Tovmasyan, A S; Fedotkina, К M; Gorovaya, E V; Arzamazov, S G; Panasov, S A

    The objective of the present work was to develop a technique for the endonasal surgical access to the maxillary sinus through crista conchalis of the maxillary bone and to evaluate the effectiveness and safety of the surgical treatment by this method. A total of 210 patients underwent the CT-assisted examination of the paranasal sinuses. The data obtained made it possible to characterize the detailed anatomical structure of crista conchalis of a maxillary bone that forms the anterior part of the medial wall of the maxillary sinus. The syntopy in relation to the distal end of the nasolacrimal canal and the cavity of the maxillary sinus was investigated. The results of the study were used to develop the original technique for endonasal antrotomy that included the 0.5-1.0 cm long vertical section of the mucous membrane at the level of the anterior end of the inferior turbinated bone approximately 1 mm from the edge of the bone aperture of the nose which exposed crista conchalis up to the place of fixation of the inferior turbinated bone. Then, the diamond drill burr was use to carry out trepanation of the medial wall of the maxillary sinus in the region of crista conchalis of the maxillary bone; sanitation of the of the sinus was followed by the apposition of the edges of the incision and their fixation with two sutures. The safety of the proposed surgical technique was confirmed by results of the repeated CT examinations of the paranasal sinus and its effectiveness by the clinical follow-up observations.

  17. Potassium currents of pear-shaped hair cells in relation to their location in frog crista ampullaris.

    Science.gov (United States)

    Prigioni, I; Russo, G; Marcotti, W

    1996-07-29

    Voltage-dependent K+ currents in pear-shaped hair cells of the frog crista ampullaris were investigated in thin slice preparations using the whole-cell variant of the patch-clamp technique. Microscopy observation revealed that pear-shaped cells are located in intermediate and peripheral regions of the crista, whereas they are absent in the central region. Voltage-clamp recordings in cells from the peripheral regions revealed that the total outward K+ current could be separated pharmacologically into three distinct components: a A-type K+ current (IA); an inactivating calcium-activated K+ current (IK(Ca)) and a delayed rectifier K+ current (IK). IK and IK(Ca) exhibited similar magnitude and accounted for most of the membrane cell conductance. The same experimental protocol applied to cells from the intermediate regions showed the presence of a large and sustained IK(Ca) which represented 95% of the total outward current. In this region IA was absent. The present results demonstrated that pear-shaped hair cells located in two discrete regions of frog crista ampullaris exhibit a different complement of voltage-dependent conductances, suggesting that they can play a different role in processing the natural stimulus.

  18. Electron tomographic analysis reveals ultrastructural features of mitochondrial cristae architecture which reflect energetic state and aging.

    Science.gov (United States)

    Jiang, Yi-Fan; Lin, Shao-Syuan; Chen, Jing-Min; Tsai, Han-Zen; Hsieh, Tao-Shih; Fu, Chi-Yu

    2017-03-30

    Within mitochondria, the ability to produce energy relies upon the architectural hallmarks of double membranes and cristae invaginations. Herein, we describe novel features of mitochondrial cristae structure, which correspond to the energetic state of the organelle. In concordance with high-energy demand, mitochondria of Drosophila indirect flight muscle exhibited extensive intra-mitochondrial membrane switches between densely packed lamellar cristae that resulted in a spiral-like cristae network and allowed for bidirectional matrix confluency. This highly interconnected architecture is expected to allow rapid equilibration of membrane potential and biomolecules across integrated regions. In addition, mutant flies with mtDNA replication defect and an accelerated aging phenotype accumulated mitochondria that contained subsections of swirling membrane alongside normal cristae. The swirling membrane had impaired energy production capacity as measured by protein composition and function. Furthermore, mitochondrial fusion and fission dynamics were affected in the prematurely aged flies. Interestingly, the normal cristae that remained in the mitochondria with swirling membranes maintained acceptable function that camouflaged them from quality control elimination. Overall, structural features of mitochondrial cristae were described in three-dimension from serial section electron tomographic analysis which reflect energetic state and mtDNA-mediated aging.

  19. Explaining transgression in respiratory rate observation methods in the emergency department: A classic grounded theory analysis.

    Science.gov (United States)

    Flenady, Tracy; Dwyer, Trudy; Applegarth, Judith

    2017-09-01

    Abnormal respiratory rates are one of the first indicators of clinical deterioration in emergency department(ED) patients. Despite the importance of respiratory rate observations, this vital sign is often inaccurately recorded on ED observation charts, compromising patient safety. Concurrently, there is a paucity of research reporting why this phenomenon occurs. To develop a substantive theory explaining ED registered nurses' reasoning when they miss or misreport respiratory rate observations. This research project employed a classic grounded theory analysis of qualitative data. Seventy-nine registered nurses currently working in EDs within Australia. Data collected included detailed responses from individual interviews and open-ended responses from an online questionnaire. Classic grounded theory (CGT) research methods were utilised, therefore coding was central to the abstraction of data and its reintegration as theory. Constant comparison synonymous with CGT methods were employed to code data. This approach facilitated the identification of the main concern of the participants and aided in the generation of theory explaining how the participants processed this issue. The main concern identified is that ED registered nurses do not believe that collecting an accurate respiratory rate for ALL patients at EVERY round of observations is a requirement, and yet organizational requirements often dictate that a value for the respiratory rate be included each time vital signs are collected. The theory 'Rationalising Transgression', explains how participants continually resolve this problem. The study found that despite feeling professionally conflicted, nurses often erroneously record respiratory rate observations, and then rationalise this behaviour by employing strategies that adjust the significance of the organisational requirement. These strategies include; Compensating, when nurses believe they are compensating for errant behaviour by enhancing the patient's outcome

  20. Classroom Use of Multimedia-Supported Predict Observe Explain Tasks in a Social Constructivist Learning Environment

    Science.gov (United States)

    Kearney, Matthew

    2004-08-01

    This paper focuses on the use of multimedia-based predict-observe-explain (POE) tasks to facilitate small group learning conversations. Although the tasks were given to pairs of students as a diagnostic tool to elicit their pre-instructional physics conceptions, they also provided a peer learning opportunity for students. The study adopted a social constructivist perspective to analyse and interpret the students conversations, focussing on students articulation and justification of their own science conceptions, clarification of and critical reflection on their partners views, and negotiation of new, shared meanings. Two senior science classes participated in this interpretive study. Data sources were mainly qualitative and included audio and video recordings of students small group discussions at the computer, interviews with selected students and their teachers, classroom observations, and student surveys. Findings indicate that the computer-based POE tasks supported students peer learning conversations, particularly during the prediction, reasoning and observation stages of the POE strategy. The increased level of student control of the POE tasks, combined with the multimedia nature of the program, initiated quality peer discussions. The findings have implications for authentic, technology-mediated learning in science.

  1. Endoscopic surgery in the treatment of crista galli pneumatization evolving with localizated frontal headaches

    Directory of Open Access Journals (Sweden)

    Socher, Jan Alessandro

    2014-01-01

    Full Text Available Introduction: The crista galli is part of the ethmoid bone and thus may suffer from the process of pneumatization. Pneumatization occurs in between 3% and 14% of patients, resulting from air cells in the frontal or ethmoid sinuses. Aim: To describe 3 cases of crista galli pneumatization in which the patients developed infection and were treated surgically by endoscopic techniques. Method: We present 3 case studies of patients complaining of severe frontal headaches. The patients underwent ENT evaluation, examination by video-endoscopy, and computed tomography, which identified crista galli pneumatization with mucosal thickening and the presence of fluid. Patients underwent treatment with antibiotics and corticosteroids; however, they showed no symptomatic improvement, displayed recurrence of symptoms, and maintained radiographic changes. Thus, patients then underwent drainage through the crista galli via an endoscopic procedure. Discussion: During surgery, mucopurulence and/or mucosal thickening and edema were identified in the pneumatized crista galli. There were no complications during or after surgery. Postoperatively, headache was improved in patients after a minimum follow-up of 6 months. Conclusion: Crista galli pneumatization can result in infection, simulating rhinosinusitis. When there is little response to drug therapy, endoscopic surgical treatment is required; the current cases demonstrate that this technique is safe and effective.

  2. Can we explain the observed methane variability after the Mount Pinatubo eruption?

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    Bândă, N.; 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 the evolution of CH4 after the eruption, their contributions to the observed variations are not yet resolved. CH4 is removed from the atmosphere by the reaction with tropospheric OH, which in turn is produced by O3 photolysis under UV radiation. The CH4 removal after the Pinatubo eruption might have been affected by changes in tropospheric UV levels due to the presence of stratospheric SO2 and sulfate aerosols, and due to enhanced ozone depletion on Pinatubo aerosols. The perturbed climate after the eruption also altered both sources and sinks of atmospheric CH4. Furthermore, CH4 concentrations were influenced by other factors of natural variability in that period, such as El Niño-Southern Oscillation (ENSO) and biomass burning events. Emissions of CO, NOX and non-methane volatile organic compounds (NMVOCs) also affected CH4 concentrations indirectly by influencing tropospheric OH levels.Potential drivers of CH4 variability are investigated using the TM5 global chemistry model. The contribution that each driver had to the global CH4 variability during the period 1990 to 1995 is quantified. We find that a decrease of 8-10 ppb yr-1 CH4 is explained by a combination of the above processes. However, the timing of the minimum growth rate is found 6&nash;9 months later than observed. The long-term decrease in CH4 growth rate over the period 1990 to 1995 is well captured and can be attributed to an increase in OH concentrations over this time period. Potential uncertainties in our modelled CH4 growth rate include emissions of CH4 from wetlands, biomass burning emissions of CH4 and other compounds, biogenic NMVOC and the sensitivity of OH to NMVOC emission changes. Two

  3. Exploring students' perceptions and performance on predict-observe-explain tasks in high school chemistry laboratory

    Science.gov (United States)

    Vadapally, Praveen

    This study sought to understand the impact of gender and reasoning level on students' perceptions and performances of Predict-Observe-Explain (POE) laboratory tasks in a high school chemistry laboratory. Several literature reviews have reported that students at all levels have not developed the specific knowledge and skills that were expected from their laboratory work. Studies conducted over the last several decades have found that boys tend to be more successful than girls in science and mathematics courses. However, some recent studies have suggested that girls may be reducing this gender gap. This gender difference is the focal point of this research study, which was conducted at a mid-western, rural high school. The participants were 24 boys and 25 girls enrolled in two physical science classes taught by the same teacher. In this mixed methods study, qualitative and quantitative methods were implemented simultaneously over the entire period of the study. MANOVA statistics revealed significant effects due to gender and level of reasoning on the outcome variables, which were POE performances and perceptions of the chemistry laboratory environment. There were no significant interactions between these effects. For the qualitative method, IRB-approved information was collected, coded, grouped, and analyzed. This method was used to derive themes from students' responses on questionnaires and semi-structured interviews. Students with different levels of reasoning and gender were interviewed, and many of them expressed positive themes, which was a clear indication that they had enjoyed participating in the POE learning tasks and they had developed positive perceptions towards POE inquiry laboratory learning environment. When students are capable of formal reasoning, they can use an abstract scientific concept effectively and then relate it to the ideas they generate in their minds. Thus, instructors should factor the nature of students' thinking abilities into their

  4. 4D-var assimilation of CRISTA-NF H2O and MLS retrievals with the high resolution SACADA system

    Science.gov (United States)

    Kasradze, Ketevan; Elbern, Hendrik; Schwinger, Jörg

    2010-05-01

    SACADA is a 4-dimensional variational assimilation system for trace gas observations. A novel global chemistry transport model with its adjoint version is the kernel of this system. Since the German Weather Service global forecast model (GME) is used as an online meteorological driver, the icosahedral grid structure and the horizontal transport are adopted from GME. Recently the horizontal and vertical scheme resolution of the model grid was refined: The distance of the horizontal grid points was reduced to about 150 km and vertical separation between grid levels is now less then 1 km below 22 km altitude. In order to better describe chemical processes in the lower stratosphere/upper troposphere (UT/LS) the chemistry module was extended and revised. All this modifications were done in order to draw full advantage from high resolution limb sounding instruments, like CRISTA-NF (Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere - New Frontiers). As a case study, assimilation of MLS (Microwave Limb Sounder) data with diagnosis of observation and background error statistics in observation space for H2O was performed. Relative humidity is used to filter observations and the background field. It is shown that the H2O analysis significantly improves compared to the ECMWF operational analisys. Additionally, data from the CRISTA-NF instrument, which has been operated on board the Russian high altitude research aircraft M-55 Geophysica, was assimilated. These CRISTA-NF observations have been taken during the AMMA (African Mansoon Measurements Analysis) Campaign in summer 2006 by ICG I (Institute of Chemistry and Dynamics of the Geosphere, Research Centre Jülich). A basic finding is that the H2O-analysis based on the additional CRISTA data in the UT/LS region improves with the SACADA high resolution configuration.

  5. Error-based analysis of optimal tuning functions explains phenomena observed in sensory neurons

    Directory of Open Access Journals (Sweden)

    Steve Yaeli

    2010-10-01

    Full Text Available Biological systems display impressive capabilities in effectively responding to environmental signals in real time. There is increasing evidence that organisms may indeed be employing near optimal Bayesian calculations in their decision-making. An intriguing question relates to the properties of optimal encoding methods, namely determining the properties of neural populations in sensory layers that optimize performance, subject to physiological constraints. Within an ecological theory of neural encoding/decoding, we show that optimal Bayesian performance requires neural adaptation which reflects environmental changes. Specifically, we predict that neuronal tuning functions possess an optimal width, which increases with prior uncertainty and environmental noise, and decreases with the decoding time window. Furthermore, even for static stimuli, we demonstrate that dynamic sensory tuning functions, acting at relatively short time scales, lead to improved performance. Interestingly, the narrowing of tuning functions as a function of time was recently observed in several biological systems. Such results set the stage for a functional theory which may explain the high reliability of sensory systems, and the utility of neuronal adaptation occurring at multiple time scales.

  6. New evidence for positive selection helps explain the paternal age effect observed in achondroplasia

    Science.gov (United States)

    Shinde, Deepali N.; Elmer, Dominik P.; Calabrese, Peter; Boulanger, Jérôme; Arnheim, Norman; Tiemann-Boege, Irene

    2013-01-01

    There are certain de novo germline mutations associated with genetic disorders whose mutation rates per generation are orders of magnitude higher than the genome average. Moreover, these mutations occur exclusively in the male germ line and older men have a higher probability of having an affected child than younger ones, known as the paternal age effect (PAE). The classic example of a genetic disorder exhibiting a PAE is achondroplasia, caused predominantly by a single-nucleotide substitution (c.1138G>A) in FGFR3. To elucidate what mechanisms might be driving the high frequency of this mutation in the male germline, we examined the spatial distribution of the c.1138G>A substitution in a testis from an 80-year-old unaffected man. Using a technology based on bead-emulsion amplification, we were able to measure mutation frequencies in 192 individual pieces of the dissected testis with a false-positive rate lower than 2.7 × 10−6. We observed that most mutations are clustered in a few pieces with 95% of all mutations occurring in 27% of the total testis. Using computational simulations, we rejected the model proposing an elevated mutation rate per cell division at this nucleotide site. Instead, we determined that the observed mutation distribution fits a germline selection model, where mutant spermatogonial stem cells have a proliferative advantage over unmutated cells. Combined with data on several other PAE mutations, our results support the idea that the PAE, associated with a number of Mendelian disorders, may be explained primarily by a selective mechanism. PMID:23740942

  7. The Role of Post-Perovskite in Explaining Observations of Seismic Anisotropy

    Science.gov (United States)

    Cottaar, S.; Li, M.; McNamara, A. K.; Romanowicz, B. A.; Wenk, H. R.

    2014-12-01

    Increasing evidence is emerging for the presence of strong seismic anisotropy in D'' based on the observation of various seismic phases. To explain these observations in terms of crystal preferred orientation, and test for the presence and deformation mechanisms of post-perovskite, we apply a multi-disciplinary forward model approach. Our setup in this study is quite similar to our earlier study in 2D (Wenk et al., 2011). We employ a 3D geodynamical model with temperature-dependent viscosity and kinematic velocity boundary conditions defined at the surface of the Earth to form a broad downwelling slab. Tracers in the geodynamical model track the velocity gradient tensor in the slab at the surface down to the core-mantle boundary. The deformational information in the lower mantle is fed into a viscoplastic polycrystal plascticity model, in which we assume all deformation is accommodated by dislocation creep. We test models of either perovskite or post-perovskite mixed with periclase. For the post-perovskite phase we vary which slip system is most active. We average single crystal elastic constants over the crystal pole orientations to obtain seismically distinguishable models of anisotropy. The four resulting synthetic anisotropy models are evaluated against published seismic observations by comparing different anisotropic components: the radial anisotropy, the splitting for (sub-)vertical phases (i.e. azimuthal anisotropy), and the splitting for sub-horizontal phases. The patterns in shear radial anisotropy and splitting in sub-horizontal phases are consistent with post-perovskite with dominant slip on the (010)- and (001)-planes, confirming our earlier results in 2D. Overall, the (001)-model shows stronger anisotropy than the (010)-model, and its strongest patch localizes where the slab impinges on the core-mantle boundary. Radial anisotropy for P-waves could further constrain whether a slip system on the (010)-plane or the (001)-plane is most active. The

  8. Incidence of Third Trochanter/Crista Glutei in Human Femora in Central Indian Population

    Directory of Open Access Journals (Sweden)

    Rupa Chhaparwal

    2017-04-01

    Full Text Available Background: The third trochanter is a rounded bony projection which may be present along the superior border of the gluteal tuberosity of the femur.Sometime there is linear elevation along the gluteal tuberosity called as crista glutei. If conical projection is present in the gluteal tuberosity, it is called as third trochanter. Aim and Objectives: To undertake the study of incidences of third trochanter and crista glutei in central Indian population this study was undertaken and to compare it with occurrence in other series. Material and Methods: Fifty dry adult human femora collected from the Department of Anatomy and examined carefully. The third trochanter was considered to be present only if distinct oval elevation was separate from gluteal ridge. When there is linear elevation along the gluteal tuberosity we considered it as crista glutei. This classification was distinguished from that of a gluteal tuberosity. The length and width was measured using a digital vernier caliper. Results: The total incidence of third trochanter (oval elevation and crista glutei (linear elevation were found to occur in 14% and 24% with left sided predominance. Conclusion: Important findings of present work highlight the morphometric indices of third trochanter and crista glutei. Parameters that have been studied in the present work can be utilized for anthropometric, comparative and functional studies.

  9. Comparative study on anti-oxidant and anti-inflammatory activities of Caesalpinia crista and Centella asiatica leaf extracts.

    Science.gov (United States)

    Ramesh, B N; Girish, T K; Raghavendra, R H; Naidu, K Akhilender; Rao, U J S Prasada; Rao, K S

    2014-04-01

    Amyloidosis, oxidative stress and inflammation have been strongly implicated in neurodegenerative disorders like Alzheimer's disease. Traditionally, Caesalpinia crista and Centella asiatica leaf extracts are used to treat brain related diseases in India. C. crista is used as a mental relaxant drink as well as to treat inflammatory diseases, whereas C. asiatica is reported to be used to enhance memory and to treat dementia. The present study is aimed to understand the anti-oxidant and anti-inflammatory potential of C. asiatica and C. crista leaf extracts. Phenolic acid composition of the aqueous extracts of C. crista and C. asiatica were separated on a reverse phase C18 column (4.6 x 250 mm) using HPLC system. Antioxidant properties of the leaf extracts were determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay and the reducing potential assay. The anti-inflammatory activities of aqueous extracts of C. crista and C. asiatica were studied using 5-lipoxygenase assay. Polymorphonuclear leukocytes (PMNLs) were isolated from blood by Ficoll-Histopaque density gradient followed by hypotonic lysis of erythrocytes. Gallic, protocatechuic, gentisic, chlorogenic, caffeic, p-coumaric and ferulic acids were the phenolic acids identified in C. crista and C. asiatica leaf aqueous extracts. However, gallic acid and ferulic acid contents were much higher in C. crista compared to C. asiatica. Leaf extracts of C. asiatica and C. crista exhibited antioxidant properties and inhibited 5-lipoxygenase (anti-inflammatory) in a dose dependent manner. However, leaf extracts of C. crista had better antioxidant and anti-inflammatory activity compared to that of C. asiatica. The better activity of C. crista is attributed to high gallic acid and ferulic acid compared to C. asiatica. Thus, the leaf extract of C. crista can be a potential therapeutic role for Alzheimer's disease.

  10. 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

  11. Changes in the chloroplastic CO2 concentration explain much of the observed Kok effect: a model.

    Science.gov (United States)

    Farquhar, Graham D; Busch, Florian A

    2017-04-01

    Mitochondrial respiration often appears to be inhibited in the light when compared with measurements in the dark. This inhibition is inferred from the response of the net CO2 assimilation rate (A) to absorbed irradiance (I), changing slope around the light compensation point (Ic ). We suggest a model that provides a plausible mechanistic explanation of this 'Kok effect'. The model uses the mathematical description of photosynthesis developed by Farquhar, von Caemmerer and Berry; it involves no inhibition of respiration rate in the light. We also describe a fitting technique for quantifying the Kok effect at low I. Changes in the chloroplastic CO2 partial pressure (Cc ) can explain curvature of A vs I, its diminution in C4 plants and at low oxygen concentrations or high carbon dioxide concentrations in C3 plants, and effects of dark respiration rate and of temperature. It also explains the apparent inhibition of respiration in the light as inferred by the Laisk approach. While there are probably other sources of curvature in A vs I, variation in Cc can largely explain the curvature at low irradiance, and suggests that interpretation of day respiration compared with dark respiration of leaves on the basis of the Kok effect needs reassessment. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  12. The observed human sperm mutation frequency cannot explain the achondroplasia paternal age effect

    Science.gov (United States)

    Tiemann-Boege, Irene; Navidi, William; Grewal, Raji; Cohn, Dan; Eskenazi, Brenda; Wyrobek, Andrew J.; Arnheim, Norman

    2002-01-01

    The lifelong spermatogonial stem cell divisions unique to male germ cell production are thought to contribute to a higher mutation frequency in males. The fact that certain de novo human genetic conditions (e.g., achondroplasia) increase in incidence with the age of the father is consistent with this idea. Although it is assumed that the paternal age effect is the result of an increasing frequency of mutant sperm as a man grows older, no direct molecular measurement of the germ-line mutation frequency has been made to confirm this hypothesis. Using sperm DNA from donors of different ages, we determined the frequency of the nucleotide substitution in the fibroblast growth factor receptor 3 (FGFR3) gene that causes achondroplasia. Surprisingly, the magnitude of the increase in mutation frequency with age appears insufficient to explain why older fathers have a greater chance of having a child with this condition. A number of alternatives may explain this discrepancy, including selection for sperm that carry the mutation or an age-dependent increase in premutagenic lesions that remain unrepaired in sperm and are inefficiently detected by the PCR assay. PMID:12397172

  13. Characterizing Students' Attempts to Explain Observations from Practical Work: Intermediate Phases of Understanding

    Science.gov (United States)

    Mestad, Idar; Kolstø, Stein Dankert

    2017-10-01

    This study aims to characterize a group of students' preliminary oral explanations of a scientific phenomenon produced as part of their learning process. The students were encouraged to use their own wordings to test out their own interpretation of observations when conducting practical activities. They presented their explanations orally in the whole class after having discussed and written down an explanation in a small group. The data consists of transcribed video recordings of the presented explanations, observation notes, and interviews. A genre perspective was used to characterize the students' explanations together with analysis of the students use of scientific terms, gestures, and the language markers "sort of" and "like." Based on the analysis we argue to separate between event-focused explanations, where the students describe how objects move, and object-focused explanations, where the students describe object properties and interactions. The first type uses observable events and few scientific terms, while the latter contains object properties and tentative use of scientific terms. Both types are accompanied by an extensive use of language markers and gestures. A third category, term-focused explanations, is used when the students only provide superficial explanations by expressing scientific terms. Here, the students' use of language markers and gestures are low. The analyses shows how students' explanations can be understood as tentative attempts to build on their current understanding and observations while trying to reach out for a deeper and scientific way of identifying observations and building explanations and new ways of talking.

  14. Can natural variability explain the discrepancy between observed and modeled sea ice trends?

    CERN Document Server

    Rosenblum, Erica

    2016-01-01

    Observations indicate that the Arctic sea ice cover is rapidly retreating while the Antarctic sea ice cover is steadily expanding. State-of-the-art climate models, by contrast, tend to predict a moderate decrease in both the Arctic and Antarctic sea ice covers. A number of recent studies have attributed this discrepancy in each hemisphere to natural variability, suggesting that the models are consistent with the observations when simulated natural variability is taken into account. Here we examine sea ice changes during 1979-2013 in simulations from the most recent Coupled Model Intercomparison Project (CMIP5) as well as the Community Earth System Model Large Ensemble (CESM-LE). We find that accurately simulated Arctic sea ice retreat occurs only in simulations with too much global warming, whereas accurately simulated Antarctic sea ice expansion tends to occur in simulations with too little global warming. We show that because of this, simulations from both ensembles do not capture the observed asymmetry bet...

  15. Shift of subtropical transport barriers explains observed hemispheric asymmetry of decadal trends of age of air

    Directory of Open Access Journals (Sweden)

    G. P. Stiller

    2017-09-01

    Full Text Available In response to global warming, the Brewer–Dobson circulation in the stratosphere is expected to accelerate and the mean transport time of air along this circulation to decrease. This would imply a negative stratospheric age of air trend, i.e. an air parcel would need less time to travel from the tropopause to any point in the stratosphere. Age of air as inferred from tracer observations, however, shows zero to positive trends in the northern mid-latitude stratosphere and zonally asymmetric patterns. Using satellite observations and model calculations we show that the observed latitudinal and vertical patterns of the decadal changes of age of air in the lower to middle stratosphere during the period 2002–2012 are predominantly caused by a southward shift of the circulation pattern by about 5°. After correction for this shift, the observations reveal a hemispherically almost symmetric decrease of age of air in the lower to middle stratosphere up to 800 K of up to −0.25 years over the 2002–2012 period with strongest decrease in the northern tropics. This net change is consistent with long-term trends from model predictions.

  16. The observer's guide to planetary motion explaining the cycles of the night sky

    CERN Document Server

    Ford, Dominic

    2014-01-01

    To the naked eye, the most evident defining feature of the planets is their motion across the night sky. It was this motion that allowed ancient civilizations to single them out as different from fixed stars. But how does the geometry of the Solar System give rise to the observed motions of the planets and their moons? Although the motions of the planets may be described as simple elliptical orbits around the Sun, they must be observed from a particular vantage point--the Earth, which spins daily on its axis and circles around the Sun each year, resulting in more complicated patterns. The Observer’s Guide to Planetary Motion provides accurate tables of the best time for observing each planet, together with other notable events in their orbits, helping amateur astronomers plan when and what to observe. Along the way, many questions are answered: Why does Mars take over two years between apparitions (the times when it is visible from Earth) in the night sky, while Uranus and Neptune take almost exactly a yea...

  17. Characterizing Students' Attempts to Explain Observations from Practical Work: Intermediate Phases of Understanding

    Science.gov (United States)

    Mestad, Idar; Kolstø, Stein Dankert

    2017-01-01

    This study aims to characterize a group of students' preliminary oral explanations of a scientific phenomenon produced as part of their learning process. The students were encouraged to use their own wordings to test out their own interpretation of observations when conducting practical activities. They presented their explanations orally in the…

  18. The clinical anatomy of the crista terminalis, pectinate muscles and the teniae sagittalis.

    Science.gov (United States)

    Loukas, Marios; Tubbs, R Shane; Tongson, Jonathan M; Polepalli, Shrikaant; Curry, Brian; Jordan, Robert; Wagner, Teresa

    2008-01-01

    The crista terminalis (CT) is an important anatomic landmark due its close association with the sinoatrial node artery and the origin of the pectinate muscles (PM). However, the gross anatomy of the PM in relation to the CT has not been well described. The aim of our study has been to investigate the location and the morphology of PM in relation to the CT. We examined 300 adult formalin-fixed human hearts. All PM originated from the CT and extended along the wall of the appendage toward the vestibule of the tricuspid valve. It was observed that the PM varied significantly with respect to arrangement and course of its fibers. We were able to classify the course of the PM, including the most prominent PM called the tenia sagittalis (TS), into 6 different patterns with 3 different TS types. In Type A (15%), the TS was absent. Type B (65%) demonstrated a single TS and Type C (20%) was characterized by the presence of multiple TS. Furthermore, the course of the PM was classified into 6 patterns: Type I (40%), the PM was oriented perpendicular to the CT with uniform spacing and lack of crossover (trabeculation); Type II (20%), non-uniform PM was organized in a haphazard, trabecular fashion with numerous crossovers; Type III (15%), the PM had uniform spacing with no trabeculation with fibers oriented parallel to the CT; Type IV (10%), had arborizing PM originating from a common muscular trunk (solitary trunk); Type V (10%), fibers were oriented both perpendicular and parallel to the CT, similar in architecture to Type III, but with more than one common muscular trunk; Type VI (5%), prominent muscular column with velamentous PM with potential implications in cardiac catheterization procedures. The exact morphology of PM and TS may be clinically important in right atrial catheterization procedures, as well as in the development of arrhythmias but further investigations are now necessary to prove this theory.

  19. Observed decrease in atmospheric mercury explained by global decline in anthropogenic emissions

    Science.gov (United States)

    Yanxu Zhang,; Daniel J. Jacob,; Hannah M. Horowitz,; Long Chen,; Helen M. Amos,; Krabbenhoft, David P.; Franz Slemr,; Vincent L. St. Louis,; Elsie M. Sunderland,

    2015-01-01

    Observations of elemental mercury (Hg0) at sites in North America and Europe show large decreases (∼1–2% y−1) from 1990 to present. Observations in background northern hemisphere air, including Mauna Loa Observatory (Hawaii) and CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) aircraft flights, show weaker decreases (inventories indicating flat or increasing emissions over that period. However, the inventories have three major flaws: (i) they do not account for the decline in atmospheric release of Hg from commercial products; (ii) they are biased in their estimate of artisanal and small-scale gold mining emissions; and (iii) they do not properly account for the change in Hg0/HgII speciation of emissions from coal-fired utilities after implementation of emission controls targeted at SO2 and NOx. We construct an improved global emission inventory for the period 1990 to 2010 accounting for the above factors and find a 20% decrease in total Hg emissions and a 30% decrease in anthropogenic Hg0 emissions, with much larger decreases in North America and Europe offsetting the effect of increasing emissions in Asia. Implementation of our inventory in a global 3D atmospheric Hg simulation [GEOS-Chem (Goddard Earth Observing System-Chemistry)] coupled to land and ocean reservoirs reproduces the observed large-scale trends in atmospheric Hg0 concentrations and in HgII wet deposition. The large trends observed in North America and Europe reflect the phase-out of Hg from commercial products as well as the cobenefit from SO2 and NOx emission controls on coal-fired utilities.

  20. Life-stage, not climate change, explains observed tree range shifts

    Science.gov (United States)

    Máliš, František; Kopecký, Martin; Petřík, Petr; Vladovič, Jozef; Merganič, Ján; Vida, Tomáš

    2017-01-01

    Ongoing climate change is expected to shift tree species distribution and therefore affect forest biodiversity and ecosystem services. To assess and project tree distributional shifts, researchers may compare the distribution of juvenile and adult trees under the assumption that differences between tree life-stages reflect distributional shifts triggered by climate change. However, the distribution of tree life-stages could differ within the lifespan of trees, therefore we hypothesize that currently observed distributional differences could represent shifts over ontogeny as opposed to climatically driven changes. Here we test this hypothesis with data from 1435 plots resurveyed after more than three decades across the Western Carpathians. We compared seedling, sapling and adult distribution of 12 tree species along elevation, temperature and precipitation gradients. We analyzed i) temporal shifts between the surveys and ii) distributional differences between tree life-stages within both surveys. Despite climate warming, tree species distribution of any life-stage did not shift directionally upward along elevation between the surveys. Temporal elevational shifts were species-specific and an order of magnitude lower than differences among tree life-stages within the surveys. Our results show that the observed range shifts among tree life-stages are more consistent with ontogenetic differences in the species’ environmental requirements than with responses to recent climate change. The distribution of seedlings substantially differed from saplings and adults, while the distribution of saplings did not differ from adults, indicating a critical transition between seedling and sapling tree life-stages. Future research has to take ontogenetic differences among life-stages into account as we found that distributional differences recently observed worldwide may not reflect climate change but rather the different environmental requirements of tree life-stages. PMID:26725258

  1. Weird Astronomy Tales of Unusual, Bizarre, and Other Hard to Explain Observations

    CERN Document Server

    Seargent, David A.J

    2011-01-01

    You go out for a night’s observing and look up at the sky. There are all the usual suspects—a splattering of stars, the Moon, Venus, maybe Mercury and Mars. Perhaps you can identify some of the constellations. If you are using binoculars or a small telescope, you can see many wonders not revealed to the naked eye but still well known to telescope users for centuries. But what if you look up and see something completely new, something unexplainable. Do your eyes deceive you? Are you really seeing what you think you are seeing? What should you do? In this fascinating account of the many oddball things people – from novice astronomers to certified experts – have observed over the years, you will be introduced to a number of unusual – and sometimes still unexplainable – phenomena occurring in our usually familiar and reassuring skies. What exactly did they see? What discoveries followed these unusual sightings? What remains unexplained? In addition to the accounts, you will find scattered throughout t...

  2. Hypothesis to Explain the Size Effect Observed in APO-BMI Compression Tests

    Energy Technology Data Exchange (ETDEWEB)

    Schembri, Philip Edward [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Siranosian, Antranik Antonio [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kingston, Lance Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-01-07

    In 2013 compression tests were performed on cylindrical specimens of carbon-microballoon-APOBMI syntactic foam machined to different lengths (0.25, 0.5, and 2.8 inches1) (Kingston, 2013). In 2014 similar tests were performed on glass-microballoon-APO-BMI of different lengths (~0.15”, ~0.32”, and ~0.57”). In all these tests it was observed that, when strains were calculated from the platen displacement (corrected for machine compliance), the apparent Young’s modulus of the material decreased with specimen size, as shown in Table 1. The reason for this size effect was speculated to be a layer of damage on or near the top and bottom machined surfaces of the specimens (Kingston, Schembri, & Siranosian, 2014). This report examines that hypothesis in further detail.

  3. Kin-Aggregations Explain Chaotic Genetic Patchiness, a Commonly Observed Genetic Pattern, in a Marine Fish.

    Directory of Open Access Journals (Sweden)

    Jason D Selwyn

    Full Text Available The phenomenon of chaotic genetic patchiness is a pattern commonly seen in marine organisms, particularly those with demersal adults and pelagic larvae. This pattern is usually associated with sweepstakes recruitment and variable reproductive success. Here we investigate the biological underpinnings of this pattern in a species of marine goby Coryphopterus personatus. We find that populations of this species show tell-tale signs of chaotic genetic patchiness including: small, but significant, differences in genetic structure over short distances; a non-equilibrium or "chaotic" pattern of differentiation among locations in space; and within locus, within population deviations from the expectations of Hardy-Weinberg equilibrium (HWE. We show that despite having a pelagic larval stage, and a wide distribution across Caribbean coral reefs, this species forms groups of highly related individuals at small spatial scales (<10 metres. These spatially clustered family groups cause the observed deviations from HWE and local population differentiation, a finding that is rarely demonstrated, but could be more common than previously thought.

  4. Flickering AGN can explain the strong circumgalactic O VI observed by COS-Halos

    Science.gov (United States)

    Oppenheimer, Benjamin D.; Segers, Marijke; Schaye, Joop; Richings, Alexander J.; Crain, Robert A.

    2018-03-01

    Proximity zone fossils (PZFs) are ionization signatures around recently active galactic nuclei (AGNs) where metal species in the circumgalactic medium remain overionized after the AGNs have shut off due to their long recombination time scales. We explore cosmological zoom hydrodynamic simulations, using the EAGLE (Evolution and Assembly of GaLaxies and their Environments) model paired with a non-equilibrium ionization and cooling module including time-variable AGN radiation to model PZFs around star-forming disc galaxies in the z ˜ 0.2 Universe. Previous simulations typically underestimated the O VI content of galactic haloes, but we show that plausible PZF models increase O VI column densities by 2 - 3 × to achieve the levels observed around COS-Halos star-forming galaxies out to 150 kpc. Models with AGN bolometric luminosities ≳ 1043.6erg s- 1, duty cycle fractions ≲ 10 per cent, and AGN lifetimes ≲ 106 yr are the most promising, because their supermassive black holes grow at the cosmologically expected rate and they mostly appear as inactive AGN, consistent with COS-Halos. The central requirement is that the typical star-forming galaxy hosted an active AGN within a time-scale comparable to the recombination time of a high metal ion, which for circumgalactic O VI is ≈107 yr. H I, by contrast, returns to equilibrium much more rapidly due to its low neutral fraction and does not show a significant PZF effect. O VI absorption features originating from PZFs appear narrow, indicating photoionization, and are often well aligned with lower metal ion species. PZFs are highly likely to affect the physical interpretation of circumgalactic high ionization metal lines if, as expected, normal galaxies host flickering AGN.

  5. Crista acustica in insect ears modeled by an inhomogenous granular chain

    OpenAIRE

    Delevoye, Elisabeth; Tournat, Vincent

    2012-01-01

    International audience; Insect ears are found on the thorax (in some Hemiptera), the abdomen (in grasshoppers, cicadas, some moths), or the front tibia (in crickets, katydids). Crista acustica -also named Siebold's organs- is the sensory organ linked to tympanum when located in forelegs. It is a collection of individually-tuned scolopidia -the most fundamental unit of mechanoreceptor organs in insects- that can discriminate frequencies. A remarkable geometrical property of the arrangement of ...

  6. Integration of superoxide formation and cristae morphology for mitochondrial redox signaling

    Czech Academy of Sciences Publication Activity Database

    Plecitá-Hlavatá, Lydie; Ježek, Petr

    2016-01-01

    Roč. 80, Nov (2016), s. 31-50 ISSN 1357-2725 R&D Projects: GA ČR(CZ) GA16-04788S; GA ČR(CZ) GA16-06700S Institutional support: RVO:67985823 Keywords : redox signaling * mitochondrial cristae morphology * ATP-synthase dimers * OPA1 * MICOS Subject RIV: EA - Cell Biology Impact factor: 3.505, year: 2016

  7. Structure of dimeric mitochondrial ATP synthase: Novel F0 bridging features and the structural basis of mitochondrial cristae biogenesis

    National Research Council Canada - National Science Library

    Fernando Minauro-Sanmiguel; Stephan Wilkens; José J. García

    2005-01-01

    .... How two ATP synthase complexes dimerize to promote cristae formation is unknown. Here we resolved the structure of the dimeric F 1 F 0 ATP synthase complex isolated from bovine heart mitochondria by transmission electron microscopy...

  8. Observe, Explain, Connect

    Science.gov (United States)

    Vardell, Sylvia M.; Wong, Janet S.

    2014-01-01

    Like science, poetry often involves a high level of abstraction in language and ideas, requiring specific critical-thinking skills and promoting interaction. Casteel and Isom (1994) acknowledge, "The literacy processes are the means by which science content is learned because content information is rooted in written and oral language"…

  9. Effectiveness of Cooperative Learning Instructional Tools With Predict-Observe-Explain Strategy on the Topic of Cuboid and Cube Volume

    Science.gov (United States)

    Nurhuda; Lukito, A.; Masriyah

    2018-01-01

    This study aims to develop instructional tools and implement it to see the effectiveness. The method used in this research referred to Designing Effective Instruction. Experimental research with two-group pretest-posttest design method was conducted. The instructional tools have been developed is cooperative learning model with predict-observe-explain strategy on the topic of cuboid and cube volume which consist of lesson plans, POE tasks, and Tests. Instructional tools were of good quality by criteria of validity, practicality, and effectiveness. These instructional tools was very effective for teaching the volume of cuboid and cube. Cooperative instructional tool with predict-observe-explain (POE) strategy was good of quality because the teacher was easy to implement the steps of learning, students easy to understand the material and students’ learning outcomes completed classically. Learning by using this instructional tool was effective because learning activities were appropriate and students were very active. Students’ learning outcomes were completed classically and better than conventional learning. This study produced a good instructional tool and effectively used in learning. Therefore, these instructional tools can be used as an alternative to teach volume of cuboid and cube topics.

  10. Risk of bias and brand explain the observed inconsistency in trials on glucosamine for symptomatic relief of osteoarthritis

    DEFF Research Database (Denmark)

    Eriksen, Patrick; Bartels, Else M; Altman, Roy D

    2014-01-01

    OBJECTIVE: To determine whether study sponsor, chemical formulation, brand of glucosamine, and/or risk of bias explain observed inconsistencies in trials of glucosamine's efficacy for treating pain in osteoarthritis (OA). METHODS: A systematic review and stratified meta-analysis of randomized......)]) served as effect size. RESULTS: The inclusion criteria yielded 25 trials (3,458 patients). Glucosamine moderately reduced pain (SMD -0.51 [95% CI -0.72, -0.30]), although a high level of between-trial inconsistency was observed (I(2) = 88%). The single most important explanation (i.e., covariate......) was brand, reducing heterogeneity by 41% (P = 0.00032). Twelve trials (1,437 patients) using the Rottapharm/Madaus product resulted in significant pain reduction (SMD -1.07 [95% CI -1.47, -0.67]), although a sensitivity analysis of 3 low risk of bias trials using the Rottapharm/Madaus product showed less...

  11. Using participant or non-participant observation to explain information behaviour. Participant observation, Non-participant observation, Information behaviour, Hospital pharmacists, Older people

    Directory of Open Access Journals (Sweden)

    Janet Cooper

    2004-01-01

    Full Text Available The aim of the paper is to provide guidance on conducting participant and non-participant observation studies of information behaviour. Examines lessons learned during non-participant observation of hospital pharmacists, and participant observation with dependent older people living in their own homes. Describes the methods used in both studies, and discusses the ethical issues involved in gaining access to the subjects. In the hospital setting, professional affiliation between the researcher and the subjects (six pharmacists made access easier to obtain. In the home care setting, access to subjects (seven clients for participant observation (as a care worker was more difficult, as was withdrawal from the field study. In both studies, the observation element was triangulated with survey data. Both studies indicated the fundamental need for trust between the observer and the research subjects. In some situations, professional relations offer instant access and trust, whereas in closed and sensitive situations such as social care, time is required to build up trust. With participant observation, that trust should not be damaged by withdrawal of the researcher from the research setting.

  12. A data-model synthesis to explain variability in calcification observed during a CO2 perturbation mesocosm experiment

    Science.gov (United States)

    Krishna, Shubham; Schartau, Markus

    2017-04-01

    The effect of ocean acidification on growth and calcification of the marine algae Emiliania huxleyi was investigated in a series of mesocosm experiments where enclosed water volumes that comprised a natural plankton community were exposed to different carbon dioxide (CO2) concentrations. Calcification rates observed during those experiments were found to be highly variable, even among replicate mesocosms that were subject to similar CO2 perturbations. Here, data from an ocean acidification mesocosm experiment are reanalysed with an optimality-based dynamical plankton model. According to our model approach, cellular calcite formation is sensitive to variations in CO2 at the organism level. We investigate the temporal changes and variability in observations, with a focus on resolving observed differences in total alkalinity and particulate inorganic carbon (PIC). We explore how much of the variability in the data can be explained by variations of the initial conditions and by the level of CO2 perturbation. Nine mesocosms of one experiment were sorted into three groups of high, medium, and low calcification rates and analysed separately. The spread of the three optimised ensemble model solutions captures most of the observed variability. Our results show that small variations in initial abundance of coccolithophores and the prevailing physiological acclimation states generate differences in calcification that are larger than those induced by ocean acidification. Accordingly, large deviations between optimal mass flux estimates of carbon and of nitrogen are identified even between mesocosms that were subject to similar ocean acidification conditions. With our model-based data analysis we document how an ocean acidification response signal in calcification can be disentangled from the observed variability in PIC.

  13. Syndrome de Leopard, distúrbio da crista neural: relato de um caso

    Directory of Open Access Journals (Sweden)

    Marco Aurelio Lana Peixoto

    1981-06-01

    Full Text Available A síndrome de Leopard é uma condição autosoma dominante de variável expressão fenotípica. Uma minoria apenas dos pacientes apresenta todos os componentes da síndrome, ou seja, lentigenes múltiplas (L, alterações eletrocardiográficos (E, hipertelorismo ocular (O, estenose pulmonar (P, anormalidades genitais (A, retardo de crescimento (R, e surdez neurosensorial (D. Descrevemos o caso de uma criança com todos os componentes da síndrome além de outras anomalias não descritas anteriormente, tais como macroglossia, alterações dentárias, megacolon, ectopia anal e hipertrofia do clitoris, impressão basilar e platibasia. A presença de alterações dentárias e megacolon, representando envolvimento das papilas dentárias e de plexo mioentérico, derivados da crista neural, constitui nova evidência que favorece a hipótese de ser a síndrome de Leopard resultante de anomalia dos elementos da crista neural.

  14. Can nuclear physics explain the anomaly observed in the internal pair production in the Beryllium-8 nucleus?

    Science.gov (United States)

    Zhang, Xilin; Miller, Gerald A.

    2017-10-01

    Recently the experimentalists in Krasznahorkay (2016) [1] announced observing an unexpected enhancement of the e+-e- pair production signal in one of the 8Be nuclear transitions. The subsequent studies have been focused on possible explanations based on introducing new types of particle. In this work, we improve the nuclear physics modeling of the reaction by studying the pair emission anisotropy and the interferences between different multipoles in an effective field theory inspired framework, and examine their possible relevance to the anomaly. The connection between the previously measured on-shell photon production and the pair production in the same nuclear transitions is established. These improvements, absent in the original experimental analysis, should be included in extracting new particle's properties from the experiment of this type. However, the improvements can not explain the anomaly. We then explore the nuclear transition form factor as a possible origin of the anomaly, and find the required form factor to be unrealistic for the 8Be nucleus. The reduction of the anomaly's significance by simply rescaling our predicted event count is also investigated.

  15. Can nuclear physics explain the anomaly observed in the internal pair production in the Beryllium-8 nucleus?

    Directory of Open Access Journals (Sweden)

    Xilin Zhang

    2017-10-01

    Full Text Available Recently the experimentalists in Krasznahorkay (2016 [1] announced observing an unexpected enhancement of the e+–e− pair production signal in one of the 8Be nuclear transitions. The subsequent studies have been focused on possible explanations based on introducing new types of particle. In this work, we improve the nuclear physics modeling of the reaction by studying the pair emission anisotropy and the interferences between different multipoles in an effective field theory inspired framework, and examine their possible relevance to the anomaly. The connection between the previously measured on-shell photon production and the pair production in the same nuclear transitions is established. These improvements, absent in the original experimental analysis, should be included in extracting new particle's properties from the experiment of this type. However, the improvements can not explain the anomaly. We then explore the nuclear transition form factor as a possible origin of the anomaly, and find the required form factor to be unrealistic for the 8Be nucleus. The reduction of the anomaly's significance by simply rescaling our predicted event count is also investigated.

  16. Differences in oral sexual behaviors by gender, age, and race explain observed differences in prevalence of oral human papillomavirus infection.

    Science.gov (United States)

    D'Souza, Gypsyamber; Cullen, Kevin; Bowie, Janice; Thorpe, Roland; Fakhry, Carole

    2014-01-01

    This study explores whether gender, age and race differences in oral sexual behavior account for the demographic distribution of oral human papillomavirus infection (HPV) and HPV-positive oropharyngeal cancer (HPV-OSCC). This analysis included 2,116 men and 2,140 women from NHANES (2009-10) who answered a behavioral questionnaire and provided an oral-rinse sample for HPV detection. Weighted prevalence estimates and prevalence ratios (PR) were calculated for sexual behaviors and oral HPV infection by gender, age-cohort (20-29, 30-44, 45-59, 60-69), and race, and contrasted with incidence rate ratios (IRR) of OSCC from SEER 2009. Multivariate logistic regression was used to evaluate predictors of oral sexual behavior and oral HPV16 infection. Differences in oral sexual behavior were observed by gender, age-cohort and race. Most men (85.4%) and women (83.2%) had ever performed oral sex, but men had more lifetime oral and vaginal sexual partners and higher oral HPV16 prevalence than women (each pHPV16 prevalence was similar. Prevalence ratios (PR) of ever oral sex in men vs. women (PR = 1.03), and 45-59 vs. 30-44 year-old men (PR = 0.96) were modest relative to ratios for oral HPV16 infection (PRs = 1.3-6.8) and OSCC (IRR = 4.7-8.1). In multivariate analysis, gender, age-cohort, and race were significant predictors of oral sexual behavior. Oral sexual behavior was the primary predictor of oral HPV16 infection; once this behavior was adjusted for, age-cohort and race were no longer associated with oral HPV16. There are differences in oral sexual behaviors when considering gender, age-cohort and race which explain observed epidemiologic differences in oral HPV16 infection across these groups.

  17. Differences in oral sexual behaviors by gender, age, and race explain observed differences in prevalence of oral human papillomavirus infection.

    Directory of Open Access Journals (Sweden)

    Gypsyamber D'Souza

    Full Text Available This study explores whether gender, age and race differences in oral sexual behavior account for the demographic distribution of oral human papillomavirus infection (HPV and HPV-positive oropharyngeal cancer (HPV-OSCC.This analysis included 2,116 men and 2,140 women from NHANES (2009-10 who answered a behavioral questionnaire and provided an oral-rinse sample for HPV detection. Weighted prevalence estimates and prevalence ratios (PR were calculated for sexual behaviors and oral HPV infection by gender, age-cohort (20-29, 30-44, 45-59, 60-69, and race, and contrasted with incidence rate ratios (IRR of OSCC from SEER 2009. Multivariate logistic regression was used to evaluate predictors of oral sexual behavior and oral HPV16 infection.Differences in oral sexual behavior were observed by gender, age-cohort and race. Most men (85.4% and women (83.2% had ever performed oral sex, but men had more lifetime oral and vaginal sexual partners and higher oral HPV16 prevalence than women (each p<0.001. 60-69 year olds (yo were less likely than 45-59 or 30-44 (yo to have performed oral sex (72.7%, 84.8%, and 90.3%, p<0.001, although oral HPV16 prevalence was similar. Prevalence ratios (PR of ever oral sex in men vs. women (PR = 1.03, and 45-59 vs. 30-44 year-old men (PR = 0.96 were modest relative to ratios for oral HPV16 infection (PRs = 1.3-6.8 and OSCC (IRR = 4.7-8.1. In multivariate analysis, gender, age-cohort, and race were significant predictors of oral sexual behavior. Oral sexual behavior was the primary predictor of oral HPV16 infection; once this behavior was adjusted for, age-cohort and race were no longer associated with oral HPV16.There are differences in oral sexual behaviors when considering gender, age-cohort and race which explain observed epidemiologic differences in oral HPV16 infection across these groups.

  18. Hepatoprotective Potential of Caesalpinia crista against Iron-Overload-Induced Liver Toxicity in Mice

    Directory of Open Access Journals (Sweden)

    Rhitajit Sarkar

    2012-01-01

    Full Text Available The present study was carried out to evaluate the ameliorating effect of Caesalpinia crista Linn. (CCME extract on iron-overload-induced liver injury. Iron overload was induced by intraperitoneal administration of iron dextran into mice. CCME attenuated the percentage increase in liver iron and serum ferritin levels when compared to control group. CCME also showed a dose-dependent inhibition of lipid peroxidation, protein oxidation, and liver fibrosis. The serum enzyme markers were found to be less, whereas enhanced levels of liver antioxidant enzymes were detected in CCME-treated group. In presence of CCME, the reductive release of ferritin iron was increased significantly. Furthermore, CCME exhibited DPPH radical scavenging and protection against Fe2+-mediated oxidative DNA damage. The current study confirmed the hepatoprotective effect of CCME against the model hepatotoxicant iron overload and the activity is likely related to its potent antioxidant and iron-chelating property.

  19. Ionospheric measurements during the CRISTA/MAHRSI campaign: their implications and comparison with previous campaigns

    Directory of Open Access Journals (Sweden)

    J. Laštovicka

    Full Text Available The CRISTA/MAHRSI experiment on board a space shuttle was accompanied by a broad campaign of rocket, balloon and ground-based measurements. Supporting lower ionospheric ground-based measurements were run in Europe and Eastern Asia between 1 October-30 November, 1994. Results of comparisons with long ionospheric data series together with short-term comparisons inside the interval October-November, 1994, showed that the upper middle atmosphere 
    (h = 80-100 km at middle latitudes of the Northern Hemisphere in the interval of the CRISTA/MAHRSI experiment (4-12 November, 1994 was very close to its expected climatological state. In other words, the average results of the experiment can be used as climatological data, at least for the given area/altitudes. The role of solar/geomagnetic and "meteorological" control of the lower ionosphere is investigated and compared with the results of MAP/WINE, MAC/SINE and DYANA campaigns. The effects of both solar/geomagnetic and global meteorological factors on the lower ionosphere are found to be weak during autumn 1994 compared to those in MAP/WINE and DYANA winters, and they are even slightly weaker than those in MAP/SINE summer. The comparison of the four campaigns suggests the following overall pattern: in winter the lower ionosphere at northern middle latitudes appears to be fairly well "meteorologically" controlled with a very weak solar influence. In summer, solar influence is somewhat stronger and dominates the weak "meteorological" influence, but the overall solar/meteorological control is weaker than in winter. In autumn we find the weakest overall solar/meteorological control, local effects evidently dominate.

    Key words. Ionosphere (ionosphere · atmosphere interactions; mid-latitude ionosphere

  20. The amyloid beta-peptide is imported into mitochondria via the TOM import machinery and localized to mitochondrial cristae

    DEFF Research Database (Denmark)

    Hansson Petersen, Camilla A; Alikhani, Nyosha; Behbahani, Homira

    2008-01-01

    potential. Subfractionation studies following the import experiments revealed Abeta association with the inner membrane fraction, and immunoelectron microscopy after import showed localization of Abeta to mitochondrial cristae. A similar distribution pattern of Abeta in mitochondria was shown...... by immunoelectron microscopy in human cortical brain biopsies obtained from living subjects with normal pressure hydrocephalus. Thus, we present a unique import mechanism for Abeta in mitochondria and demonstrate both in vitro and in vivo that Abeta is located to the mitochondrial cristae. Importantly, we also show...... that extracellulary applied Abeta can be internalized by human neuroblastoma cells and can colocalize with mitochondrial markers. Together, these results provide further insight into the mitochondrial uptake of Abeta, a peptide considered to be of major significance in Alzheimer's disease....

  1. "Cristal tachycardias": origin of right atrial tachycardias from the crista terminalis identified by intracardiac echocardiography.

    Science.gov (United States)

    Kalman, J M; Olgin, J E; Karch, M R; Hamdan, M; Lee, R J; Lesh, M D

    1998-02-01

    We sought to use intracardiac echocardiography (ICE) to identify the anatomic origin of focal right atrial tachycardias and to define their relation with the crista terminalis (CT). Previous studies using ICE during mapping of atrial flutter and inappropriate sinus tachycardia have demonstrated an important relation between endocardial anatomy and electrophysiologic events. Recent studies have suggested that right atrial tachycardias may also have a characteristic anatomic distribution. Twenty-three consecutive patients with 27 right atrial tachycardias were included in the study. ICE was used to facilitate activation mapping in relation to endocardial structures. A 20-pole catheter was positioned along the CT under ICE guidance. ICE was also used to assist in guiding detailed mapping with the ablation catheter in the right atrium. Of 27 focal right atrial tachycardias, 18 (67%, 95% confidence interval [CI] 46% to 83%) were on the CT (2 high medial, 8 high lateral, 6 mid and 2 low). ICE identified the location of the tip of the ablation catheter in immediate relation to the CT in all 18 cases. The 20-pole mapping catheter together with echocardiographic visualization of the CT provided a guide to the site of tachycardia origin along this structure. Radiofrequency ablation was successful in 26 (96%) of 27 (95% CI 81% to 100%) right atrial tachycardias. This study demonstrates that approximately two thirds of focal right atrial tachycardias occurring in the absence of structural heart disease will arise along the CT. Recognition of this common distribution may potentially facilitate mapping and ablation of these tachycardias.

  2. Modeling and Explaining Content: Definition, Research Support, and Measurement of the "ETS"® National Observational Teaching Examination (NOTE) Assessment Series. Research Memorandum No. RM-16-07

    Science.gov (United States)

    Stickler, Leslie; Sykes, Gary

    2016-01-01

    This report reviews the scholarly and research evidence supporting the construct labeled modeling and explaining content (MEC), which is measured via a performance assessment in the "ETS"® National Observational Teaching Examination (NOTE) assessment series. This construct involves practices at the heart of teaching that deal with how…

  3. Imaging cytochrome C oxidase and FoF1-ATP synthase in mitochondrial cristae of living human cells by FLIM and superresolution microscopy

    Science.gov (United States)

    Foertsch, Franziska; Ilchenko, Mykhailo; Heitkamp, Thomas; Noßmann, Silke; Hoffmann, Birgit; Starke, Ilka; Mrowka, Ralf; Biskup, Christoph; Börsch, Michael

    2017-02-01

    Cytochrome C oxidase and FoF1-ATP synthase constitute complex IV and V, respectively, of the five membrane-bound enzymes in mitochondria comprising the respiratory chain. These enzymes are located in the inner mitochondrial membrane (IMM), which exhibits large invaginations called cristae. According to recent electron cryotomography, FoF1-ATP synthases are located predominantly at the rim of the cristae, while cytochrome C oxidases are likely distributed in planar membrane areas of the cristae. Previous FLIM measurements (K. Busch and coworkers) of complex II and III unravelled differences in the local environment of the membrane enzymes in the cristae. Here, we tagged complex IV and V with mNeonGreen and investigated their mitochondrial nano-environment by FLIM and superresolution microscopy in living human cells. Different lifetimes and anisotropy values were found and will be discussed.

  4. Fenologia e visitantes florais de Erythrina crista-galli L. (Leguminosae: Faboideae em Santa Maria, Rio Grande do Sul, Brasil

    Directory of Open Access Journals (Sweden)

    Raimunda Alice Coimbra Vieira Costa

    2008-01-01

    Full Text Available http://dx.doi.org/10.5007/2175-7925.2008v21n2p51 Erythrina crista-galli é uma espécie característica do bioma Pampa, também usada com fins ornamentais em arborização urbana. E. crista-galli  floresce mais intensamente de novembro a dezembro. A antese inicia entre 7h-11h, e as flores têm duração de cinco dias. Um total de 1.275 visitas florais foi registrado em 57h de observações. Abelhas da família Apidae (Trigona spinipes e Apis mellifera foram os visitantes fl orais mais freqüentes (88,23%, seguidos de moscas (Muscidae – 5,50%, formigas (Formicidae – 2,35%, vespas (Vespidae –  1,56% e besouros (Chrysomelidae – 1,56%. As flores também foram visitadas por beija-flores da família Trochilidae (Chlorostilbon aureoventris (0,79%. A abelha T. spinipes foi observada em todos os horários e apresentou comportamento de possível polinizadora, juntamente com A. mellifera e o beija-fl or C. aureoventris. E. crista-galli é autocompatível, apresentando produção de frutos e sementes após a polinização manual e sob condições naturais.

  5. Is the Theory of Mind deficit observed in visual paradigms in schizophrenia explained by an impaired attention toward gaze orientation?

    Science.gov (United States)

    Roux, Paul; Forgeot d'Arc, Baudoin; Passerieux, Christine; Ramus, Franck

    2014-08-01

    Schizophrenia is associated with poor Theory of Mind (ToM), particularly in goal and belief attribution to others. It is also associated with abnormal gaze behaviors toward others: individuals with schizophrenia usually look less to others' face and gaze, which are crucial epistemic cues that contribute to correct mental states inferences. This study tests the hypothesis that impaired ToM in schizophrenia might be related to a deficit in visual attention toward gaze orientation. We adapted a previous non-verbal ToM paradigm consisting of animated cartoons allowing the assessment of goal and belief attribution. In the true and false belief conditions, an object was displaced while an agent was either looking at it or away, respectively. Eye movements were recorded to quantify visual attention to gaze orientation (proportion of time participants spent looking at the head of the agent while the target object changed locations). 29 patients with schizophrenia and 29 matched controls were tested. Compared to controls, patients looked significantly less at the agent's head and had lower performance in belief and goal attribution. Performance in belief and goal attribution significantly increased with the head looking percentage. When the head looking percentage was entered as a covariate, the group effect on belief and goal attribution performance was not significant anymore. Patients' deficit on this visual ToM paradigm is thus entirely explained by a decreased visual attention toward gaze. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. The structural organization of seed oil bodies could explain the contrasted oil extractability observed in two rapeseed genotypes.

    Science.gov (United States)

    Boulard, Céline; Bardet, Michel; Chardot, Thierry; Dubreucq, Bertrand; Gromova, Marina; Guillermo, Armel; Miquel, Martine; Nesi, Nathalie; Yen-Nicolaÿ, Stéphanie; Jolivet, Pascale

    2015-07-01

    The protein, phospholipid and sterol composition of the oil body surface from the seeds of two rapeseed genotypes was compared in order to explain their contrasted oil extractability. In the mature seeds of oleaginous plants, storage lipids accumulate in specialized structures called oil bodies (OBs). These organelles consist of a core of neutral lipids surrounded by a phospholipid monolayer in which structural proteins are embedded. The physical stability of OBs is a consequence of the interactions between proteins and phospholipids. A detailed study of OB characteristics in mature seeds as well as throughout seed development was carried out on two contrasting rapeseed genotypes Amber and Warzanwski. These two accessions were chosen because they differ dramatically in (1) crushing ability, (2) oil extraction yield and, (3) the stability of purified OBs. Warzanwski has higher crushing ability, better oil extraction yield and less stable purified OBs than Amber. OB morphology was investigated in situ using fluorescence microscopy, transmission electron microscopy and pulsed field gradient NMR. During seed development, OB diameter first increased and then decreased 30 days after pollination in both Amber and Warzanwski embryos. In mature seeds, Amber OBs were significantly smaller. The protein, phospholipid and sterol composition of the hemi-membrane was compared between the two accessions. Amber OBs were enriched with H-oleosins and steroleosins, suggesting increased coverage of the OB surface consistent with their higher stability. The nature and composition of phospholipids and sterols in Amber OBs suggest that the hemi-membrane would have a more rigid structure than that of Warzanwski OBs.

  7. Observed an aerial phenomenon that you can't explain? The UAP Observations Reporting Scheme as a tool for demystifying UFOs and stimulating interest in Science

    Science.gov (United States)

    Ailleris, P.

    2011-10-01

    We present the website's extensive and well illustrated list of misidentifications and describe how people can further check details and develop their knowledge (e.g. satellite paths, stars/planets charts, characteristics of meteors, pictures of sprites, clouds classification). A short illustrated list of cases will be featured, both explained and inexplicable; and outreach activities and partnerships with relevant astronomical projects (e.g. Astronomers without Borders, The World at Night) will be described. We will underline that the project definitely fulfills a need in relation to demystifying UFO events, providing education on pseudo-scientific information, while keeping an attitude of scientific openmindedness. For these reasons, we will encourage the planetary scientists community to further advertise the project's existence and the amateur astronomers and societies who receive questions about UFOs to redirect those queries to the websit.

  8. Why the 18.6 year tide cannot explain the change of sign observed in j2

    Directory of Open Access Journals (Sweden)

    F. Deleflie

    2003-01-01

    Full Text Available Recent studies show a change, starting in 1998, in the behavior of the variation of the dynamical flattening of the Earth (J2, supposed to be constant (secular, and mainly due to the post glacial rebound effect. In this paper, we study to what extent this behavior can be correlated or not with the 18.6 year tide: with more than twenty years of tracking data on LAGEOS-1, that is to say more than a period of 18.6 years, this effect can now be separated from the secular variation. We use our theory of mean orbital motion, dedicated to studies of the long period effects on the orbital motion. We build one single arc of LAGEOS-1 from 1980 to 2002, which provides a continuous description of the orbital parameters. This is the great originality of our approach. We focus our attention on the ascending node of LAGEOS-1, and we show that the change observed in j2 cannot be attributed to a statistical error due to a correlation, in short arcs results, between the secular variation of J2 and the 18.6 year tide. The proof is based on the adjustment of amplitudes and phases of the long period tides, and on the shape of the residuals.Key words. secular variation of J2, 18.6 year tide, mean orbital motione

  9. 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.

  10. 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

  11. Can the observed association between serum perfluoroalkyl substances and delayed menarche be explained on the basis of puberty-related changes in physiology and pharmacokinetics?

    Science.gov (United States)

    Wu, Huali; Yoon, Miyoung; Verner, Marc-André; Xue, Jianping; Luo, Man; Andersen, Melvin E; Longnecker, Matthew P; Clewell, Harvey J

    2015-09-01

    An association between serum levels of two perfluoroalkyl substances (PFAS) and delayed age at menarche was reported in a cross-sectional study of adolescents. Because perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have half-lives of years, growth dilution and the development of a new route of excretion (menstruation) could account for some or all of the reported association. To assess how much of the epidemiologic association between PFAS and delayed menarche can be explained by the correlation of growth and maturation with PFAS body burden. We developed a Monte Carlo (MC) physiologically-based pharmacokinetic (PBPK) model of PFAS to simulate plasma PFAS levels in a hypothetical female population aged 2 to 20years old. Realistic distributions of physiological parameters as well as timing of growth spurts and menarche were incorporated in the model. The association between PFAS level and delayed menarche in the simulated data was compared with the reported association. The prevalence of menarche, distributions of age-dependent physiological parameters, and quartiles of serum PFAS concentrations in the simulated subjects were comparable to those reported in the epidemiologic study. The delay of menarche in days per natural log increase in PFAS concentrations in the simulated data were about one third as large as the observed values. The reported relationship between PFAS and age at menarche appears to be at least partly explained by pharmacokinetics rather than a toxic effect of these substances. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. A novel approach for craniofacial symmetry evaluation: Using the midsagittal Reference line drawn from “Crista Gali” with NHP technique

    Directory of Open Access Journals (Sweden)

    Morteza Ordobazari

    2013-11-01

    Full Text Available Please cite this article as: Ordobazari M, Naqavi Al-Hosseini AA, Zafarmand H. A novel approach for craniofacial symmetry evaluation: Using the midsagittal Reference line drawn from “Crista Gali” with NHP technique. Novel Biomed 2013;1(2:48-53.Background and objective: The purpose of this study was the determination of midsagittal reference line (MSL for craniofacial asymmetry assessment by drawing a line from Crista gali parallel to the true vertical line in PA cephalometry, using Natural Head Position (NHP technique.Method and Materials: 60 Iranian subjects within the age range of 9-13 years old were selected for this prospective study. Patients referred for orthodontic treatment and ghad no supernumerary or missing teeth, no skeletal anomaly, or any history of orthodontic and jaw surgery with normal occlusion. Posteroanterior cephalometric radiographs (PA Ceph were taken of all subjects with NHP technique. The midsagittal line was also traced parallel to the hanging chain from Crista gali. True horizontal line (THL and true vertical line (TVL were also traced from Crista gali (Cg. Using Cartesian system based upon Cg point (0~0, the craniofacial symmetry was assessed with linear, angular and proportional measurements in PA cephalogam, related to TVL and THL lines, for 10 bilateral (R&L anatomical landmarks. The mean differences of the above measurements in left and right sides were analyzed by T- test.Results: The proportional ratios for all left and right measurements were not statistically significant. This was true for both vertical and horizontal distances. The significant level for MSL drawn from Cg as referred to ANS (0±0.255 and Me points (0.007±0.527 was 0.002 and 0.004, respectively.Conclusion: In posteroanterior cephalometry radiographs taken with NHP method, the MSL drawn from Crista gali is reproducible and reliable up to 96% of the times for facial symmetry diagnosis.

  13. Isolamento de DNA genômico utilizando sementes de Erythrina crista-galli L. (Corticeira-do-banhado e Schizolobium parahyba (Vell. Blake (Guapuruvu

    Directory of Open Access Journals (Sweden)

    Luciano Moura de Mello

    2015-12-01

    Full Text Available Corticeira-do-banhado is a native species, very common in southern Brazil with great potential in urban forestry. Efforts with the ge-nomic DNA isolation from leaves and exchange vascular E. crista-galli indi-cated contamination by polysaccharides or polyphenols. The Guapuruvu is native of Forest Atlantic and the isolated leaves has used successfully in the assessment of genetic di-versity. The objective of this study was to develop a new and faster protocol for DNA isolation using seeds of these species. The proposed protocol showed bet-ter qualitative and quantitative results in re-lation to the sources previously evaluated for E. crista-galli and the average time of the technical implementa-tion was significantly lower.

  14. Propagação da corticeira do banhado (Erythrina crista-galli L. (FABACEAE pelo processo de estaquia Propagation of swamp corticeira (Erythrina crista-galli L. (Fabacae by the cutting technique

    Directory of Open Access Journals (Sweden)

    Ariane Gratieri-Sossella

    2008-02-01

    Full Text Available A corticeira-do-banhado é uma árvore nativa com uso ornamental no paisagismo urbano e possui potencial de utilização em áreas desprotegidas e degradadas, devido a sua rusticidade. Entretanto, tendo em vista a dificuldade de obtenção de sementes, pela baixa produção e qualidade destas com a conseqüente desuniformidade da germinação, torna-se necessário aprofundar o estudo de outras formas de propagação dessa espécie. Desse modo, conduziu-se este trabalho na Faculdade de Agronomia e Medicina Veterinária da Universidade de Passo Fundo, com o objetivo de estudar a formação de mudas de Erythrina crista-galli L. pela técnica da estaquia. Em quatro experimentos foram testadas doses do fitorregulador ácido indolbutírico (AIB, em diferentes tipos de estacas (lenhosas, semilenhosas, herbáceas e foliares e substratos. Os resultados indicaram que mini-estacas herbáceas, coletadas de plantas jovens, com menos de 1 ano de idade, são as mais indicadas (75% a 100% de enraizamento, e o uso do AIB diminuiu a mortalidade, ao favorecer o processo do enraizamento. Em razão do ataque de insetos (brocas às plantas no seu hábitat, recomenda-se a técnica de jardim clonal, com a formação de matrizeiros no viveiro, fornecendo material juvenil e sadio em maior escala para a propagação dessa espécie por miniestacas.Swamp corticeira is a native tree with ornamental use in urban landscape gardening with the potential to be used in unprotected and degraded areas due to its rustic feature. However, the difficulty of obtaining seeds due to its low productivity and quality, and consequent lack of uniformity in its germination makes it necessary to search for other forms of propagation of this species. Thus, this study was carried out at the Agronomy and Veterinary Medicine College of Passo Fundo University, aiming to study the formation of Erythrina crista-galli L. cuttings by applying the cutting technique. Doses of phytoregulator Indol Butyric

  15. StarD7 Protein Deficiency Adversely Affects the Phosphatidylcholine Composition, Respiratory Activity, and Cristae Structure of Mitochondria.

    Science.gov (United States)

    Horibata, Yasuhiro; Ando, Hiromi; Zhang, Peixiang; Vergnes, Laurent; Aoyama, Chieko; Itoh, Masahiko; Reue, Karen; Sugimoto, Hiroyuki

    2016-11-25

    Phosphatidylcholine (PC) is a major phospholipid of mitochondria, comprising 40-50% of both the outer and the inner membranes. However, PC must be imported from its production organelles because mitochondria lack the enzymes essential for PC biosynthesis. In a previous study, we found that StarD7 mediates the intracellular transfer of PC to mitochondria. Therefore, in this study, we analyzed the contribution of StarD7 to the maintenance of mitochondrial phospholipid content and function using siRNA-mediated knockdown and knock-out (KO) of the StarD7 gene in HEPA-1 cells. Real time analysis of respiratory activity demonstrated that the oxygen consumption rate and activity of mitochondrial complexes were impaired in StarD7-KD cells. To confirm these results, we established StarD7-KO HEPA-1 cells by double nicking using CRISPR/Cas9n. As expected, StarD7-KD and -KO cells showed a significant reduction in mitochondrial PC content. The ATP level and growth rate of KO cells were notably lower compared with wild-type cells when cultured in glucose-free galactose-containing medium to force cells to rely on mitochondrial ATP production. In KO cells, the level of the MTCO1 protein, a primary subunit of complex IV, was reduced without a concomitant decrease in its mRNA, but the level was restored when StarD7-I was overexpressed. StarD7-KO cells showed impaired formation of the mitochondrial supercomplexes and exhibited a disorganized cristae structure, with no changes in optic atrophy 1 protein. These findings indicate that StarD7 plays important roles in maintaining the proper composition of mitochondrial phospholipids as well as mitochondrial function and morphogenesis. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. Assessing Changes in High School Students' Conceptual Understanding through Concept Maps before and after the Computer-Based Predict-Observe-Explain (CB-POE) Tasks on Acid-Base Chemistry at the Secondary Level

    Science.gov (United States)

    Yaman, Fatma; Ayas, Alipasa

    2015-01-01

    Although concept maps have been used as alternative assessment methods in education, there has been an ongoing debate on how to evaluate students' concept maps. This study discusses how to evaluate students' concept maps as an assessment tool before and after 15 computer-based Predict-Observe-Explain (CB-POE) tasks related to acid-base chemistry.…

  17. Cosmic Ray e +/(e- + e+), p-bar/p Ratios Explained by an Injection Model Based on 2 Gamma-ray Observations

    Energy Technology Data Exchange (ETDEWEB)

    Kamae, T.; /KIPAC, Menlo Park /SLAC; Lee, S.-H.; /KIPAC, Menlo Park; Baldini, L.; /INFN, Pisa; Giordano, F.; /Bari Polytechnic /INFN, Bari; Grondin, M.-H.; /Bordeaux U.; Latronico, L.; /INFN, Pisa; Lemoine-Goumard, M.; /Bordeaux U.; Sgro, C.; /INFN, Pisa; Tanaka, T.; Uchiyama, Y.; /KIPAC, Menlo Park

    2010-12-16

    We present a model of cosmic ray (CR) injection into the Galactic space based on recent {gamma}-ray observations of supernova remnants (SNRs) and pulsar wind nebulae (PWNe) by the Fermi Large Area Telescope (Fermi) and atmospheric Cherenkov telescopes (ACTs). Steady-state (SS) injection of nuclear particles and electrons (e{sup -}) from the Galactic ensemble of SNRs, and electrons and positrons (e{sup +}) from the Galactic ensemble of PWNe are assumed, with their spectra deduced from {gamma}-ray observations and recent evolution models. The ensembles of SNRs and PWNe are assumed to share the same spatial distributions and the secondary CR production in dense molecular clouds interacting with SNRs is incorporated in the model. Propagation of CRs to Earth is calculated using GALPROP with 2 source distributions and 2 Galaxy halo sizes. We show that this observation-based model reproduces the positron fraction e{sup +}/(e{sup -} + e{sup +}) and antiproton-to-proton ratio ({bar p}/p) reported by PAMELA reasonably well without calling for new sources. Significant discrepancy is found, however, between our model and the e{sup -} + e{sup +} spectrum measured by Fermi below {approx} 20 GeV. Important quantities for Galactic CRs, including their energy injection, average lifetime, and mean gas density along their typical propagation path are also presented.

  18. Innate Immunity and the Inter-exposure Interval Determine the Dynamics of Secondary Influenza Virus Infection and Explain Observed Viral Hierarchies.

    Science.gov (United States)

    Cao, Pengxing; Yan, Ada W C; Heffernan, Jane M; Petrie, Stephen; Moss, Robert G; Carolan, Louise A; Guarnaccia, Teagan A; Kelso, Anne; Barr, Ian G; McVernon, Jodie; Laurie, Karen L; McCaw, James M

    2015-08-01

    Influenza is an infectious disease that primarily attacks the respiratory system. Innate immunity provides both a very early defense to influenza virus invasion and an effective control of viral growth. Previous modelling studies of virus-innate immune response interactions have focused on infection with a single virus and, while improving our understanding of viral and immune dynamics, have been unable to effectively evaluate the relative feasibility of different hypothesised mechanisms of antiviral immunity. In recent experiments, we have applied consecutive exposures to different virus strains in a ferret model, and demonstrated that viruses differed in their ability to induce a state of temporary immunity or viral interference capable of modifying the infection kinetics of the subsequent exposure. These results imply that virus-induced early immune responses may be responsible for the observed viral hierarchy. Here we introduce and analyse a family of within-host models of re-infection viral kinetics which allow for different viruses to stimulate the innate immune response to different degrees. The proposed models differ in their hypothesised mechanisms of action of the non-specific innate immune response. We compare these alternative models in terms of their abilities to reproduce the re-exposure data. Our results show that 1) a model with viral control mediated solely by a virus-resistant state, as commonly considered in the literature, is not able to reproduce the observed viral hierarchy; 2) the synchronised and desynchronised behaviour of consecutive virus infections is highly dependent upon the interval between primary virus and challenge virus exposures and is consistent with virus-dependent stimulation of the innate immune response. Our study provides the first mechanistic explanation for the recently observed influenza viral hierarchies and demonstrates the importance of understanding the host response to multi-strain viral infections. Re

  19. Innate Immunity and the Inter-exposure Interval Determine the Dynamics of Secondary Influenza Virus Infection and Explain Observed Viral Hierarchies.

    Directory of Open Access Journals (Sweden)

    Pengxing Cao

    2015-08-01

    Full Text Available Influenza is an infectious disease that primarily attacks the respiratory system. Innate immunity provides both a very early defense to influenza virus invasion and an effective control of viral growth. Previous modelling studies of virus-innate immune response interactions have focused on infection with a single virus and, while improving our understanding of viral and immune dynamics, have been unable to effectively evaluate the relative feasibility of different hypothesised mechanisms of antiviral immunity. In recent experiments, we have applied consecutive exposures to different virus strains in a ferret model, and demonstrated that viruses differed in their ability to induce a state of temporary immunity or viral interference capable of modifying the infection kinetics of the subsequent exposure. These results imply that virus-induced early immune responses may be responsible for the observed viral hierarchy. Here we introduce and analyse a family of within-host models of re-infection viral kinetics which allow for different viruses to stimulate the innate immune response to different degrees. The proposed models differ in their hypothesised mechanisms of action of the non-specific innate immune response. We compare these alternative models in terms of their abilities to reproduce the re-exposure data. Our results show that 1 a model with viral control mediated solely by a virus-resistant state, as commonly considered in the literature, is not able to reproduce the observed viral hierarchy; 2 the synchronised and desynchronised behaviour of consecutive virus infections is highly dependent upon the interval between primary virus and challenge virus exposures and is consistent with virus-dependent stimulation of the innate immune response. Our study provides the first mechanistic explanation for the recently observed influenza viral hierarchies and demonstrates the importance of understanding the host response to multi-strain viral infections

  20. Observed Variability of Tsunamigenic Potential of Enormous Submarine Landslides Explained Through Modeling - A Comparison of the Holocene Storegga and Trænadjupet Events.

    Science.gov (United States)

    Løvholt, F.; Kim, J.; Laberg, J. S.

    2016-12-01

    The continental margin offshore Norway have experienced a range of giant submarine landslides having volumes ranging from hundreds to thousands of km3. The most recent and well documented of these events, are the 4500 BP Trænadjupet and the 8100 BP Storegga landslides. Both of these landslides are clay-rich, and involve common features such as retrogressive mass and momentum release mechanisms and weak layers that affect the tsunami generation. The retrogressive behaviour involved the release of several slide blocks which made the multistage failure and landslide evolution complex. The Storegga Slide reveals a rich and well documented onshore footprint in terms of paleotsunami deposits along the coastlines of Denmark, UK, the Faroe Islands, and Norway. In striking contrast, there exists no firm evidence of similar paleotsunami deposits from the younger Trænadjupet landslide. Here, we use a suit of new retrogressive and viscoplastic landslide models to simulate the run-out of both of these landslide events, and then couple the landslide to dispersive tsunami models. By using the new landslide models, we are able to obtain a better agreement with the observed paleotsunami deposits from the Storegga Slide compared to previous studies, and at the same time, to link the results to a landslide model that comply better with the slide morphology. Using the landslide model and soil parameters established for the Storegga Slide as the starting point, we set up a similar set of model scenarios for the Trænadjupet Slide. We discuss how the scenarios for the Trænadjupet landslide with different soil parameters produce different landslide velocities and tsunami heights. We then compare the resulting tsunami heights with constraints from the lack of onshore tsunami observations taking into account the contemporary shoreline position. Finally we briefly discuss the findings from the modeling in terms of both differences in tsunami observations and landslide morphology. The

  1. Disrupted in schizophrenia 1 (DISC1) is a constituent of the mammalian mitochondrial contact site and cristae organizing system (MICOS) complex, and is essential for oxidative phosphorylation.

    Science.gov (United States)

    Piñero-Martos, Estefanía; Ortega-Vila, Bernardo; Pol-Fuster, Josep; Cisneros-Barroso, Eugenia; Ruiz-Guerra, Laura; Medina-Dols, Aina; Heine-Suñer, Damián; Lladó, Jerònia; Olmos, Gabriel; Vives-Bauzà, Cristofol

    2016-10-01

    Disrupted in Schizophrenia-1 (DISC1) has been associated with a broad spectrum of mental disorders. DISC1 is a multi-compartmentalized protein found in the cytoplasm, centrosome, nuclei and mostly enriched in mitochondria. In order to shed light on DISC1 mitochondrial function, we have studied its topology within the organelle. We show in here that in mammals DISC1 resides in the 'Mitochondrial contact site and Cristae Organizing system' (MICOS) complex, involved in cristae organization. DISC1 knockdown in SH-SY5Y cells causes MICOS disassembly and fragmentation of the mitochondrial morphology network. Moreover, DISC1 depleted cells have decreased mitochondrial DNA (mtDNA) content and steady state levels of oxidative phosphorylation (OXPHOS) subunits. As a consequence, OXPHOS complexes and supercomplexes are partially disassembled in DISC1 knockdown cells, which suffer severe bioenergetic defects, evidenced by impaired oxygen consumption, adenosine triphosphate synthesis and mitochondrial membrane potential. Transfection of recombinant full-length human DISC1 restores MICOS complex assembly and rescues OXPHOS function, meanwhile overexpression of the DISC1 truncated form Δ597-854, known to be pathogenic, fails to rescue the bioenergetic impairment caused by DISC1 knockdown. These results should contribute to reveal DISC1 physiological function and potential pathogenic role in severe mental illnesses. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  2. MHD-kinetic Modeling of the Solar wind Interaction with the Local Interstellar Medium: Can Steady State Models Explain Voyager Observations?

    Science.gov (United States)

    Redman, A. C.; Pogorelov, N. V.; Heerikhuisen, J.; Kim, T. K.

    2016-12-01

    Because of the Voyager interstellar mission, solar wind (SW) interaction with the local interstellar medium (LISM) represents a natural laboratory for the investigation of colliding streams of partially ionized plasma. It has been known for a long time that charge exchange between ions and neutral H atoms plays a major role in this interaction. Since the mean free path of charge exchange may be as large as 50 AU, kinetic treatment of the neutral atom transport becomes an important ingredient of any SW-LISM interaction model. We use an MHD-kinetic model implemented in our in-house Multi-Scale Fluid-Kinetic Simulation Suite (MS-FLUKSS) to analyze the plasma and magnetic field distributions in the heliosphere and in the LISM beyond it. Simulations are performed using an adaptive mesh refinement technique for a set of the LISM parameters that are believed to be the best choice from the viewpoint of fitting measurement from different data sets. To specify the SW parameters, we used OMNI data averaged over an approximately 5-year period from 2010 to 2015. While this model does not include time-dependence of the SW, it allows us to make analyze the dependence of the velocity distribution at Voyager 2 and magnetic field in the LISM at Voyager 1 and arrive at important conclusions regarding the possibility of reproducing measurements with steady-state models. In particular, it is shown that the transverse velocity component at V2 is not reproduced well for any set of LISM properties. On the other hand, the boundary conditions with the magnetic field strength of about 3 microG are in agreement with Voyager 1 observations. We also demonstrate that the heliospheric magnetic field calculated in the inner heliosheath assuming a unipolar field substantially overestimates Voyager observations. This means that there should exist some mechanism to dissipate magnetic field immediately behind the termination shock.

  3. Low probability of initiating nirS transcription explains observed gas kinetics and growth of bacteria switching from aerobic respiration to denitrification.

    Directory of Open Access Journals (Sweden)

    Junaid Hassan

    2014-11-01

    Full Text Available In response to impending anoxic conditions, denitrifying bacteria sustain respiratory metabolism by producing enzymes for reducing nitrogen oxyanions/-oxides (NOx to N2 (denitrification. Since denitrifying bacteria are non-fermentative, the initial production of denitrification proteome depends on energy from aerobic respiration. Thus, if a cell fails to synthesise a minimum of denitrification proteome before O2 is completely exhausted, it will be unable to produce it later due to energy-limitation. Such entrapment in anoxia is recently claimed to be a major phenomenon in batch cultures of the model organism Paracoccus denitrificans on the basis of measured e(--flow rates to O2 and NOx. Here we constructed a dynamic model and explicitly simulated actual kinetics of recruitment of the cells to denitrification to directly and more accurately estimate the recruited fraction (Fden. Transcription of nirS is pivotal for denitrification, for it triggers a cascade of events leading to the synthesis of a full-fledged denitrification proteome. The model is based on the hypothesis that nirS has a low probability (rden, h(-1 of initial transcription, but once initiated, the transcription is greatly enhanced through positive feedback by NO, resulting in the recruitment of the transcribing cell to denitrification. We assume that the recruitment is initiated as [O2] falls below a critical threshold and terminates (assuming energy-limitation as [O2] exhausts. With rden = 0.005 h(-1, the model robustly simulates observed denitrification kinetics for a range of culture conditions. The resulting Fden (fraction of the cells recruited to denitrification falls within 0.038-0.161. In contrast, if the recruitment of the entire population is assumed, the simulated denitrification kinetics deviate grossly from those observed. The phenomenon can be understood as a 'bet-hedging strategy': switching to denitrification is a gain if anoxic spell lasts long but is a waste

  4. Low probability of initiating nirS transcription explains observed gas kinetics and growth of bacteria switching from aerobic respiration to denitrification.

    Science.gov (United States)

    Hassan, Junaid; Bergaust, Linda L; Wheat, I David; Bakken, Lars R

    2014-11-01

    In response to impending anoxic conditions, denitrifying bacteria sustain respiratory metabolism by producing enzymes for reducing nitrogen oxyanions/-oxides (NOx) to N2 (denitrification). Since denitrifying bacteria are non-fermentative, the initial production of denitrification proteome depends on energy from aerobic respiration. Thus, if a cell fails to synthesise a minimum of denitrification proteome before O2 is completely exhausted, it will be unable to produce it later due to energy-limitation. Such entrapment in anoxia is recently claimed to be a major phenomenon in batch cultures of the model organism Paracoccus denitrificans on the basis of measured e(-)-flow rates to O2 and NOx. Here we constructed a dynamic model and explicitly simulated actual kinetics of recruitment of the cells to denitrification to directly and more accurately estimate the recruited fraction (Fden). Transcription of nirS is pivotal for denitrification, for it triggers a cascade of events leading to the synthesis of a full-fledged denitrification proteome. The model is based on the hypothesis that nirS has a low probability (rden, h(-1)) of initial transcription, but once initiated, the transcription is greatly enhanced through positive feedback by NO, resulting in the recruitment of the transcribing cell to denitrification. We assume that the recruitment is initiated as [O2] falls below a critical threshold and terminates (assuming energy-limitation) as [O2] exhausts. With rden = 0.005 h(-1), the model robustly simulates observed denitrification kinetics for a range of culture conditions. The resulting Fden (fraction of the cells recruited to denitrification) falls within 0.038-0.161. In contrast, if the recruitment of the entire population is assumed, the simulated denitrification kinetics deviate grossly from those observed. The phenomenon can be understood as a 'bet-hedging strategy': switching to denitrification is a gain if anoxic spell lasts long but is a waste of energy

  5. A mechanistic PK/PD model for two anti-IL13 antibodies explains the difference in total IL-13 accumulation observed in clinical studies.

    Science.gov (United States)

    Tiwari, Abhinav; Kasaian, Marion; Heatherington, Anne C; Jones, Hannah M; Hua, Fei

    2016-07-01

    IMA-638 and IMA-026 are humanized IgG1 monoclonal antibodies (mAbs) that target non-overlapping epitopes of IL-13. Separate first-in-human single ascending dose studies were conducted for each mAb. These studies had similar study designs, but mild to moderate asthmatics were recruited for the IMA-638 study and healthy subjects were recruited for the IMA-026 study. IMA-638 and IMA-026 showed similar pharmacokinetic (PK) profiles, but very different total IL-13 (free and drug bound IL-13) profiles; free IL13 was not measured. IMA-026 treatment induced a dose-dependent accumulation of total IL-13, while IMA-638 treatment led to a much smaller accumulation without any clear dose-response. To understand the differences between the two total IL-13 profiles and to predict the free IL-13 profiles for each mAb treatment, a mechanistic PK/pharmacodynamic model was developed. PK-related parameters were first fit to the mean PK profiles of each mAb separately; thereafter, the target-related parameters were fit to both total IL-13 profiles simultaneously. The IL-13 degradation rate was assumed to be the same for asthma patients and healthy subjects. The model suggests that an approximately 100× faster elimination of IL-13-IMA-638 complex than IL-13-IMA-026 complex could be responsible for the differences observed in total IL-13 profiles for the two mAbs. Furthermore, the model predicts that IMA-638 administration results in greater and more prolonged free IL-13 inhibition than equivalent dosing of IMA-026 despite similar binding KD and PK profile. In conclusion, joint modeling of two similar molecules provided mechanistic insight that the elimination rate of mAb-target complex can regulate the degree of free target inhibition.

  6. Large surface meltwater discharge from the Kangerlussuaq sector of the Greenland ice sheet during the record-warm year 2010 explained by detailed energy balance observations

    Directory of Open Access Journals (Sweden)

    D. van As

    2012-02-01

    Full Text Available This study uses data from six on-ice weather stations, calibrated MODIS-derived albedo and proglacial river gauging measurements to drive and validate an energy balance model. We aim to quantify the record-setting positive temperature anomaly in 2010 and its effect on mass balance and runoff from the Kangerlussuaq sector of the Greenland ice sheet. In 2010, the average temperature was 4.9 °C (2.7 standard deviations above the 1974–2010 average in Kangerlussuaq. High temperatures were also observed over the ice sheet, with the magnitude of the positive anomaly increasing with altitude, particularly in August. Simultaneously, surface albedo was anomalously low in 2010, predominantly in the upper ablation zone. The low albedo was caused by high ablation, which in turn profited from high temperatures and low winter snowfall. Surface energy balance calculations show that the largest melt excess (∼170% occurred in the upper ablation zone (above 1000 m, where higher temperatures and lower albedo contributed equally to the melt anomaly. At lower elevations the melt excess can be attributed to high atmospheric temperatures alone. In total, we calculate that 6.6 ± 1.0 km3 of surface meltwater ran off the ice sheet in the Kangerlussuaq catchment in 2010, exceeding the reference year 2009 (based on atmospheric temperature measurements by ∼150%. During future warm episodes we can expect a melt response of at least the same magnitude, unless a larger wintertime snow accumulation delays and moderates the melt-albedo feedback. Due to the hypsometry of the ice sheet, yielding an increasing surface area with elevation, meltwater runoff will be further amplified by increases in melt forcings such as atmospheric heat.

  7. Explaining the symmetry breaking observed in the endofullerenes H2@C60, HF@C60, and H2O@C60.

    Science.gov (United States)

    Felker, Peter M; Vlček, Vojtěch; Hietanen, Isaac; FitzGerald, Stephen; Neuhauser, Daniel; Bačić, Zlatko

    2017-11-29

    Symmetry breaking has been recently observed in the endofullerenes M@C 60 (M = H 2 , HF, H 2 O), manifesting in the splittings of the three-fold degenerate ground states of the endohedral ortho-H 2 , ortho-H 2 O and the j = 1 level of HF. The nature of the interaction causing the symmetry breaking is established in this study. A fragment of the solid C 60 is considered, comprised of the central C 60 molecule surrounded by twelve nearest-neighbor (NN) C 60 molecules. The fullerenes have either P (major) or H (minor) orientational orderings, and are assumed to be rigid with I h symmetry. Only the central C 60 is occupied by the guest molecule M, while the NN fullerenes are all empty. The key proposition of the study is that the electrostatic interactions between the charge densities on the NN C 60 molecules and that on M inside the central C 60 give rise to the symmetry breaking responsible for the measured level splittings. Using this model, the M@C 60 level splittings of interest are calculated variationally and using perturbation theory, for both the P and H orientations. Those obtained for the dominant P orientation are in excellent agreement with the experimental results, with respect to the splitting magnitudes and patterns, for all three M@C 60 systems considered, pointing strongly to the quadrupolar M-NN interactions as the main cause of the symmetry breaking. The level splittings calculated for the H orientation are about 30 times smaller than the ones in the P orientation.

  8. Biological and molecular characterization of Streptococcus crista strains isolated from human dental biofilm by means of arbitrary primers - PCR (AP-PCR Caracterização biológica e molecular de linhagens de Streptococcus crista isoladas do biofilme dental de seres humanos através de iniciadores arbitrários - PCR (AP-PCR

    Directory of Open Access Journals (Sweden)

    Michelle Angelini

    2006-06-01

    Full Text Available Streptococcus ssp are important components of the dental biofilm and Streptococcus crista is considered to be an interesting model of bacterial interactions taking place in this biofilm. In the present work, S. crista strains were isolated from the dental biofilm of Brazilian individuals and studied with respect to their biological characteristics and their molecular profile by means of AP-PCR techniques, using the RR2, 434, OPR2, OPR8, and OPR13 primers. Results allowed us to build a similarity dendrogram. Analysis of the similarity dendrogram allowed the separation of the studied strains into similarity groups. All isolates presented fibril tufts by Transmission Electron Microscopy (TEM. These isolates were able to bind to salivary amylase and to adhere to mouth epithelial cells. Some strains displaying fibril tufts and positive adherence were not able to co-aggregate with Fusobacterium nucleatum, suggesting that different adhesin groups are present in these strains.Streptococcus spp são importantes componentes do biofilme dental sendo Streptococus crista considerado um interessante modelo de interações bacterianas que nele ocorrem. No presente trabalho linhagens de S. crista, foram isoladas do biofilme dental de indivíduos brasileiros, e estudadas em relação a suas características biológicas e ao seu perfil molecular através da técnica do AP-PCR, usando-se os iniciadores RR2, 434, OPR2, OPR8 e OPR13. Os resultados nos permitiram construir um dendrograma de similaridade. A análise do dendrograma de similaridade permitiu a separação das linhagens estudadas em grupos de similaridade. Todos os isolados apresentaram tufo de fibrilas, quando estudados por Microscopia Eletrônica de Transmissão (MET. Estes isolados foram capazes de se ligar à amilase salivar e de se aderir a células epiteliais bucais. Algumas linhagens, que apresentam tufo de fibrilas e aderência positiva, não foram capazes de coagregar com a Fusobacterium

  9. A Splicing Mutation in the Novel Mitochondrial Protein DNAJC11 Causes Motor Neuron Pathology Associated with Cristae Disorganization, and Lymphoid Abnormalities in Mice

    Science.gov (United States)

    Ioakeimidis, Fotis; Ott, Christine; Kozjak-Pavlovic, Vera; Violitzi, Foteini; Rinotas, Vagelis; Makrinou, Eleni; Eliopoulos, Elias; Fasseas, Costas; Kollias, George; Douni, Eleni

    2014-01-01

    Mitochondrial structure and function is emerging as a major contributor to neuromuscular disease, highlighting the need for the complete elucidation of the underlying molecular and pathophysiological mechanisms. Following a forward genetics approach with N-ethyl-N-nitrosourea (ENU)-mediated random mutagenesis, we identified a novel mouse model of autosomal recessive neuromuscular disease caused by a splice-site hypomorphic mutation in a novel gene of unknown function, DnaJC11. Recent findings have demonstrated that DNAJC11 protein co-immunoprecipitates with proteins of the mitochondrial contact site (MICOS) complex involved in the formation of mitochondrial cristae and cristae junctions. Homozygous mutant mice developed locomotion defects, muscle weakness, spasticity, limb tremor, leucopenia, thymic and splenic hypoplasia, general wasting and early lethality. Neuropathological analysis showed severe vacuolation of the motor neurons in the spinal cord, originating from dilatations of the endoplasmic reticulum and notably from mitochondria that had lost their proper inner membrane organization. The causal role of the identified mutation in DnaJC11 was verified in rescue experiments by overexpressing the human ortholog. The full length 63 kDa isoform of human DNAJC11 was shown to localize in the periphery of the mitochondrial outer membrane whereas putative additional isoforms displayed differential submitochondrial localization. Moreover, we showed that DNAJC11 is assembled in a high molecular weight complex, similarly to mitofilin and that downregulation of mitofilin or SAM50 affected the levels of DNAJC11 in HeLa cells. Our findings provide the first mouse mutant for a putative MICOS protein and establish a link between DNAJC11 and neuromuscular diseases. PMID:25111180

  10. Observation

    Science.gov (United States)

    Kripalani, Lakshmi A.

    2016-01-01

    The adult who is inexperienced in the art of observation may, even with the best intentions, react to a child's behavior in a way that hinders instead of helping the child's development. Kripalani outlines the need for training and practice in observation in order to "understand the needs of the children and...to understand how to remove…

  11. Observations

    DEFF Research Database (Denmark)

    Rossiter, John R.; Percy, Larry

    2013-01-01

    This article is a commentary on the theme of the 2012 ICORIA Conference held in Stockholm, which was about 'the changing role of advertising'. We propose that the role of advertising has not changed. the role of advertising has always been, and will continue to be, to sell more of the branded...... product or service or to achieve a higher price that consumers are willing to pay than would obtain in the absence of advertising. What has changed in recent years is the notable worsening of the academic-practitioner divide, which has seen academic advertising researchers pursuing increasingly...... as requiring a new model of how advertising communicates and persuades, which, as the authors' textbooks explain, is sheer nonsense and contrary to the goal of integrated marketing. We provide in this article a translation of practitioners' jargon into more scientifically acceptable terminology as well...

  12. 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.)

  13. Reporting explained variance

    Science.gov (United States)

    Good, Ron; Fletcher, Harold J.

    The importance of reporting explained variance (sometimes referred to as magnitude of effects) in ANOVA designs is discussed in this paper. Explained variance is an estimate of the strength of the relationship between treatment (or other factors such as sex, grade level, etc.) and dependent variables of interest to the researcher(s). Three methods that can be used to obtain estimates of explained variance in ANOVA designs are described and applied to 16 studies that were reported in recent volumes of this journal. The results show that, while in most studies the treatment accounts for a relatively small proportion of the variance in dependent variable scores., in., some studies the magnitude of the treatment effect is respectable. The authors recommend that researchers in science education report explained variance in addition to the commonly reported tests of significance, since the latter are inadequate as the sole basis for making decisions about the practical importance of factors of interest to science education researchers.

  14. Adenosine Triphosphate-sensitive Micro-reentrant Atrial Tachycardia Originating from the Crista Terminalis in a Patient with Chronic Renal Failure due to Thrombotic Thrombocytopenic Purpura

    Directory of Open Access Journals (Sweden)

    Shinya Sugiura, MD

    2009-01-01

    Full Text Available A 57-year-old woman with chronic renal failure due to the thrombotic thrombocytopenic purpura complained of palpitation. A 12-lead ECG showed supraventricular tachycardia with a cycle length of 375 ms. During the electrophysiological study, a tachycardia with a cycle length of 375 ms was reproducibly induced and terminated by atrial extrastimulation. The tachycardia exhibited an inverse relationship between the coupling interval of extrastimulus initiating the tachycardia, and the first postpacing return cycle, as well as an increasing pattern of resetting the tachycardia with an atrial extrastimulus. Ventricular burst pacing during tachycardia produced AV dissociation. Intravenous injections of a low dose (4 mg of adenosine triphosphate (ATP terminated the tachycardia without a preceding atrio-His bundle block. The tachycardia was diagnosed as an ATP-sensitive micro-reentrant atrial tachycardia. Real-time endocardial activation mapping using an electroanatomical mapping system revealed that the earliest activation site of the tachycardia was located at the midlateral portion of the crista terminalis. The tachycardia was abolished by focal ablation targeting the earliest activation site during tachycardia. This is the first reported case of an ATP-sensitive micro-reentrant atrial tachycardia associated with thrombotic thrombocytopenic purpura.

  15. 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

  16. Explaining the Oxbridge Figures.

    Science.gov (United States)

    Davies, Bronwyn; Harre, Rom

    1989-01-01

    Rejects sociobiological theories on female academic achievement and bases findings on social structure to explain why undergraduate women at Oxford University (England) achieve fewer first places and more second places in class honors. Bases theory on bipolarity of gender as an organizing principle of society. Claims that the double bind of social…

  17. 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...

  18. Explaining the effects of a multifaceted intervention to improve inpatient care in rural Kenyan hospitals--interpretation based on retrospective examination of data from participant observation, quantitative and qualitative studies.

    Science.gov (United States)

    English, Mike; Nzinga, Jacinta; Mbindyo, Patrick; Ayieko, Philip; Irimu, Grace; Mbaabu, Lairumbi

    2011-12-02

    We have reported the results of a cluster randomized trial of rural Kenyan hospitals evaluating the effects of an intervention to introduce care based on best-practice guidelines. In parallel work we described the context of the study, explored the process and perceptions of the intervention, and undertook a discrete study on health worker motivation because this was felt likely to be an important contributor to poor performance in Kenyan public sector hospitals. Here, we use data from these multiple studies and insights gained from being participants in and observers of the intervention process to provide our explanation of how intervention effects were achieved as part of an effort to better understand implementation in low-income hospital settings. Initial hypotheses were generated to explain the variation in intervention effects across place, time, and effect measure (indicator) based on our understanding of theory and informed by our implementation experience and participant observations. All data sources available for hospitals considered as cases for study were then examined to determine if hypotheses were supported, rejected, or required modification. Data included transcriptions of interviews and group discussions, field notes and that from the detailed longitudinal quantitative investigation. Potentially useful explanatory themes were identified, discussed by the implementing and research team, revised, and merged as part of an iterative process aimed at building more generic explanatory theory. At the end of this process, findings were mapped against a recently reported comprehensive framework for implementation research. A normative re-educative intervention approach evolved that sought to reset norms and values concerning good practice and promote 'grass-roots' participation to improve delivery of correct care. Maximal effects were achieved when this strategy and external support supervision helped create a soft-contract with senior managers clarifying

  19. Explaining the effects of a multifaceted intervention to improve inpatient care in rural Kenyan hospitals -- interpretation based on retrospective examination of data from participant observation, quantitative and qualitative studies

    Science.gov (United States)

    2011-01-01

    Background We have reported the results of a cluster randomized trial of rural Kenyan hospitals evaluating the effects of an intervention to introduce care based on best-practice guidelines. In parallel work we described the context of the study, explored the process and perceptions of the intervention, and undertook a discrete study on health worker motivation because this was felt likely to be an important contributor to poor performance in Kenyan public sector hospitals. Here, we use data from these multiple studies and insights gained from being participants in and observers of the intervention process to provide our explanation of how intervention effects were achieved as part of an effort to better understand implementation in low-income hospital settings. Methods Initial hypotheses were generated to explain the variation in intervention effects across place, time, and effect measure (indicator) based on our understanding of theory and informed by our implementation experience and participant observations. All data sources available for hospitals considered as cases for study were then examined to determine if hypotheses were supported, rejected, or required modification. Data included transcriptions of interviews and group discussions, field notes and that from the detailed longitudinal quantitative investigation. Potentially useful explanatory themes were identified, discussed by the implementing and research team, revised, and merged as part of an iterative process aimed at building more generic explanatory theory. At the end of this process, findings were mapped against a recently reported comprehensive framework for implementation research. Results A normative re-educative intervention approach evolved that sought to reset norms and values concerning good practice and promote 'grass-roots' participation to improve delivery of correct care. Maximal effects were achieved when this strategy and external support supervision helped create a soft-contract with

  20. Explaining the effects of a multifaceted intervention to improve inpatient care in rural Kenyan hospitals -- interpretation based on retrospective examination of data from participant observation, quantitative and qualitative studies

    Directory of Open Access Journals (Sweden)

    English Mike

    2011-12-01

    Full Text Available Abstract Background We have reported the results of a cluster randomized trial of rural Kenyan hospitals evaluating the effects of an intervention to introduce care based on best-practice guidelines. In parallel work we described the context of the study, explored the process and perceptions of the intervention, and undertook a discrete study on health worker motivation because this was felt likely to be an important contributor to poor performance in Kenyan public sector hospitals. Here, we use data from these multiple studies and insights gained from being participants in and observers of the intervention process to provide our explanation of how intervention effects were achieved as part of an effort to better understand implementation in low-income hospital settings. Methods Initial hypotheses were generated to explain the variation in intervention effects across place, time, and effect measure (indicator based on our understanding of theory and informed by our implementation experience and participant observations. All data sources available for hospitals considered as cases for study were then examined to determine if hypotheses were supported, rejected, or required modification. Data included transcriptions of interviews and group discussions, field notes and that from the detailed longitudinal quantitative investigation. Potentially useful explanatory themes were identified, discussed by the implementing and research team, revised, and merged as part of an iterative process aimed at building more generic explanatory theory. At the end of this process, findings were mapped against a recently reported comprehensive framework for implementation research. Results A normative re-educative intervention approach evolved that sought to reset norms and values concerning good practice and promote 'grass-roots' participation to improve delivery of correct care. Maximal effects were achieved when this strategy and external support supervision helped

  1. 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.

  2. Explaining embodied cognition results.

    Science.gov (United States)

    Lakoff, George

    2012-10-01

    From the late 1950s until 1975, cognition was understood mainly as disembodied symbol manipulation in cognitive psychology, linguistics, artificial intelligence, and the nascent field of Cognitive Science. The idea of embodied cognition entered the field of Cognitive Linguistics at its beginning in 1975. Since then, cognitive linguists, working with neuroscientists, computer scientists, and experimental psychologists, have been developing a neural theory of thought and language (NTTL). Central to NTTL are the following ideas: (a) we think with our brains, that is, thought is physical and is carried out by functional neural circuitry; (b) what makes thought meaningful are the ways those neural circuits are connected to the body and characterize embodied experience; (c) so-called abstract ideas are embodied in this way as well, as is language. Experimental results in embodied cognition are seen not only as confirming NTTL but also explained via NTTL, mostly via the neural theory of conceptual metaphor. Left behind more than three decades ago is the old idea that cognition uses the abstract manipulation of disembodied symbols that are meaningless in themselves but that somehow constitute internal "representations of external reality" without serious mediation by the body and brain. This article uniquely explains the connections between embodied cognition results since that time and results from cognitive linguistics, experimental psychology, computational modeling, and neuroscience. Copyright © 2012 Cognitive Science Society, Inc.

  3. Explaining mirror-touch synesthesia.

    Science.gov (United States)

    Ward, Jamie; Banissy, Michael J

    2015-01-01

    Mirror-touch synesthesia (MTS) is the conscious experience of tactile sensations induced by seeing someone else touched. This paper considers two different, although not mutually exclusive, theoretical explanations and, in the final section, considers the relation between MTS and other forms of synesthesia and also other kinds of vicarious perception (e.g., contagious yawning). The Threshold Theory explains MTS in terms of hyper-activity within a mirror system for touch and/or pain. This offers a good account for some of the evidence (e.g., from fMRI) but fails to explain the whole pattern (e.g., structural brain differences outside of this system; performance on some tests of social cognition). The Self-Other Theory explains MTS in terms of disturbances in the ability to distinguish the self from others. This can be construed in terms of over-extension of the bodily self in to others, or as difficulties in the control of body-based self-other representations. In this account, MTS is a symptom of a broader cognitive profile. We suggest this meets the criteria for synesthesia, despite the proximal causal mechanisms remaining largely unknown, and that the tendency to localize vicarious sensory experiences distinguishes it from other kinds of seemingly related phenomena (e.g., non-localized affective responses to observing pain).

  4. Efeito de dois níveis de proteína para machos reprodutores de corte com e sem retirada da crista Effect of two levels of protein for broiler breeders males with and without retreat of the crest

    Directory of Open Access Journals (Sweden)

    Walter Lucca

    2009-02-01

    Full Text Available O objetivo deste experimento foi avaliar o efeito de diferentes níveis de proteína bruta (PB na dieta para machos com ou sem crista. Peso corporal, volume de sêmen, número de células espermáticas e fertilidade foram os parâmetros avaliados. Foram utilizados 32 machos Cobb 500, 50% com crista inteira e 50% sem crista. Todos os machos foram submetidos às mesmas condições de manejo. Eles foram alojados em gaiolas metálicas individuais, com comedouro e bebedouro. O delineamento experimental usado foi o inteiramente casualizado com esquema fatorial 2x2, com duas condições de crista (com e sem e dois níveis de proteína bruta (12 e 16%. O sêmen foi coletado por meio do método americano e o número de células espermáticas foi determinado por meio da câmara de Neubauer. Na 42ª, 43ª e 44ª semanas de idade, seis fêmeas para cada tratamento foram inseminadas artificialmente. As inseminações foram realizadas duas vezes por semana com sêmen fresco na dose de 0,05ml. Os ovos foram coletados quatro vezes por dia, identificados, desinfetados e incubados nas mesmas condições. Depois de 21 dias de incubação, os ovos foram quebrados e examinados macroscopicamente para análise da fertilidade. O nível de 12% de proteína bruta foi suficiente para atender as exigências reprodutivas, e a permanência da crista influenciou apenas o peso corporal dos machos, em que machos com crista apresentaram maior peso corporal.The objective of this trial was evaluated the effect of different crude protein (CP levels of diet for males with or without coumbing. Body weight, semen volume, number of spermatic cells and fertility were evaluated. A total of 32 males Cobb 500 were used being 50% coumbed and 50% decoumbed males. The roosters were exposed the same management conditions in starting and rearing phases. They were housed in individual metallic cages with feeders and drinkers. The experimental design was entirely casualized in a factorial 2x2

  5. 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...

  6. Explaining wartime rape.

    Science.gov (United States)

    Gottschall, Jonathan

    2004-05-01

    In the years since the first reports of mass rapes in the Yugoslavian wars of secession and the genocidal massacres in Rwanda, feminist activists and scholars, human rights organizations, journalists, and social scientists have dedicated unprecedented efforts to document, explain, and seek solutions for the phenomenon of wartime rape. While contributors to this literature agree on much, there is no consensus on causal factors. This paper provides a brief overview of the literature on wartime rape in historical and ethnographical societies and a critical analysis of the four leading explanations for its root causes: the feminist theory, the cultural pathology theory, the strategic rape theory, and the biosocial theory. The paper concludes that the biosocial theory is the only one capable of bringing all the phenomena associated with wartime rape into a single explanatory context.

  7. Does Viewing Explain Doing?

    DEFF Research Database (Denmark)

    Hald, Gert Martin; Kuyper, Lisette; Adam, Philippe C G

    2013-01-01

    that, when controlling for important other factors, SEM consumption influences sexual behaviors. The small to moderate associations that emerged between SEM consumption and sexual behavior after controlling for other variables suggest that SEM is just one factor among many that may influence youth...... hierarchical multiple regression analyses to control for other factors, the association between SEM consumption and a variety of sexual behaviors was found to be significant, accounting for between 0.3% and 4% of the total explained variance in investigated sexual behaviors. CONCLUSIONS: This study suggests......INTRODUCTION: Concerns have been voiced that the use of sexually explicit materials (SEMs) may adversely affect sexual behaviors, particularly in young people. Previous studies have generally found significant associations between SEM consumption and the sexual behaviors investigated. However, most...

  8. Explaining climate danger

    Science.gov (United States)

    Oreskes, N.

    2016-12-01

    The idea of `managing planet Earth' is traceable back at least to the 1970s. Recently, it has been reformulated in the idea of a "good Anthropocene": the idea that humans should and can try to manage our planet now that we have become a planetary force. Yet available evidence and experience suggests that our prior attempts to do so have been plagued by under-estimation of the scale of the problems and over-estimation of our capacities to address them. In any case, Earth is not at risk—our planet will survive despite what we do or fail to do. Global climate change, for example, is not a problem for the planet, it is a problem for us. As the UNFCCC articulated in the 1990s, climate change matters because it is dangerous. Yet many Americans still do not understand why this is the case. I suggest that scientists can profitably focus attention on explaining this danger—why climate represents a threat to our health, well-being, and lives—and on what kinds of steps can be taken to reduce the danger.

  9. Superação de dormência e influência da temperatura, substrato e fotoperíodo na germinação de sementes de Erythrina crista-galli L. (FABACEAE

    Directory of Open Access Journals (Sweden)

    Luciano Moura de Mello

    2016-11-01

    Full Text Available Erythrina crista-galli L. (FABACEAE é uma árvore nativa do Brasil, Uruguai, Paraguai, Bolívia e Argentina. As Regras de Análises de Sementes - RAS não possuem orientações para a realização de testes de germinação para a espécie. O objetivo deste trabalho foi testar o desempenho de tratamentos para a superação de dormência das sementes e recomendar condições adequadas de substrato, temperatura e fotoperíodo para a realização de testes de germinação. O tratamento indicado para a superação da dormência foi a escarificação mecânica e a temperatura ótima para os testes de germinação de 30ºC constantes. Não houve diferença entre tratamentos em relação aos substratos testados nem quanto aos fotoperíodos indicando-se assim o substrato entre papel e com 8h de luz por sua praticidade e economia. Superação de dormência e influência da temperatura, substrato e fotoperíodo na germinação de sementes de Erythrina crista-galli L. (FABACEAE

  10. Tratamento cirúrgico do ameloblastoma com reconstrução de mandíbula com enxerto de crista ilíaca não vascularizado: estudo de sete casos

    Directory of Open Access Journals (Sweden)

    Daniela Venturoli Lunardi

    Full Text Available OBJETIVO: Determinar a validade do enxerto autólogo de crista ilíaca não vascularizado no tratamento cirúrgico do ameloblastoma de mandíbula. MÉTODO: Nos Serviços de Cirurgia de Cabeça e Pescoço e Semiologia Bucal do Complexo Hospitalar Heliópolis, de 1980 a 2000, foram tratados 31 pacientes com ameloblastoma de mandíbula, dos quais sete receberam enxerto de crista ilíaca autólogo, fixos com placa de titânio do sistema A-0 (quatro casos e aço inox (três casos, sendo portadores da variedade folicular (seis casos e plexiforme (um caso. RESULTADOS: Nesta análise, foi utilizado o Teste de Hipótese para a média populacional com a variança desconhecida, houve exposição da placa em três casos (40% quando a neoplasia ultrapassava a linha média e em quatro casos (60% não incidiu nenhuma complicação. CONCLUSÕES: Apesar da incidência de exposição de placa, o método é indicado na reconstrução da mandíbula de pacientes com ameloblastoma.

  11. Mystery Spiral Arms Explained?

    Science.gov (United States)

    2007-04-01

    Using a quartet of space observatories, University of Maryland astronomers may have cracked a 45-year mystery surrounding two ghostly spiral arms in the galaxy M106. The Maryland team, led by Yuxuan Yang, took advantage of the unique capabilities of NASA's Chandra X-ray Observatory, NASA's Spitzer Space Telescope, the European Space Agency's XMM-Newton X-ray observatory, and data obtained almost a decade ago with NASA's Hubble Space Telescope. NGC X-ray Image NGC 4258 X-ray Image M106 (also known as NGC 4258) is a stately spiral galaxy 23.5 million light-years away in the constellation Canes Venatici. In visible-light images, two prominent arms emanate from the bright nucleus and spiral outward. These arms are dominated by young, bright stars, which light up the gas within the arms. "But in radio and X-ray images, two additional spiral arms dominate the picture, appearing as ghostly apparitions between the main arms," says team member Andrew Wilson of the University of Maryland. These so-called "anomalous arms" consist mostly of gas. "The nature of these anomalous arms is a long-standing puzzle in astronomy," says Yang. "They have been a mystery since they were first discovered in the early 1960s." By analyzing data from XMM-Newton, Spitzer, and Chandra, Yang, Bo Li, Wilson, and Christopher Reynolds, all at the University of Maryland at College Park, have confirmed earlier suspicions that the ghostly arms represent regions of gas that are being violently heated by shock waves. Previously, some astronomers had suggested that the anomalous arms are jets of particles being ejected by a supermassive black hole in M106's nucleus. But radio observations by the National Radio Astronomy Observatory's Very Long Baseline Array, and the Very Large Array in New Mexico, later identified another pair of jets originating in the core. "It is highly unlikely that an active galactic nucleus could have more than one pair of jets," says Yang. In 2001, Wilson, Yang, and Gerald Cecil

  12. Avaliação da eficácia de bupivacaína embebida em Gelfoam® no local do enxerto ósseo de crista ilíaca

    Directory of Open Access Journals (Sweden)

    Mehmet Gamli

    2012-12-01

    Full Text Available JUSTIFICATIVA E OBJETIVOS: Um número considerável de pacientes relata dor após coleta de enxerto da crista ilíaca anterior. Este estudo avaliou a eficácia da aplicação de bupivacaína embebida em uma esponja de gelatina absorvível (Gelfoam® no local doador de osso e do uso parenteral de opioides no controle da dor pós-operatória. MÉTODO: Estudo prospectivo, duplo-cego, randomizado e controlado por placebo comparando a infiltração no período intraoperatório de 20 mL de bupivacaína (tratamento, grupo B versus soro fisiológico (placebo com Gelfoam embebida no local de coleta óssea da crista ilíaca em pacientes submetidos à cirurgia eletiva de coluna cervical. No período pós-operatório, a administração de cloridrato de hidromorfona (na sala de recuperação pós-anestésica e analgesia controlada pelo paciente foi padronizada. Um escore de dor com base em escala visual analógica (EVA com pontuação de zero a 10 foi usado para avaliar a intensidade da dor associada ao local doador. Os escores de dor e uso/frequência de narcóticos foram registrados 24 e 48 horas após a operação. Os médicos, pacientes, a equipe de enfermagem e os estatísticos desconheciam o tratamento usado. RESULTADOS: Os grupos eram semelhantes em idade, gênero e comorbidades. Não houve diferença significativa entre os grupos nos escores da EVA. As doses de narcótico foram significativamente menores no grupo B nos tempos de 24 e 48 horas (p < 0,05. CONCLUSÃO: Este estudo demonstrou que bupivacaína embebida em esponja de gelatina absorvível no local de coleta do enxerto ósseo de crista ilíaca (EOCI reduziu o uso parenteral de opioides no pós-operatório.

  13. How important are determinants of obesity measured at the individual level for explaining geographic variation in body mass index distributions? Observational evidence from Canada using Quantile Regression and Blinder-Oaxaca Decomposition.

    Science.gov (United States)

    Dutton, Daniel J; McLaren, Lindsay

    2016-04-01

    Obesity prevalence varies between geographic regions in Canada. The reasons for this variation are unclear but most likely implicate both individual-level and population-level factors. The objective of this study was to examine whether equalising correlates of body mass index (BMI) across these geographic regions could be reasonably expected to reduce differences in BMI distributions between regions. Using data from three cycles of the Canadian Community Health Survey (CCHS) 2001, 2003 and 2007 for males and females, we modelled between-region BMI cross-sectionally using quantile regression and Blinder-Oaxaca decomposition of the quantile regression results. We show that while individual-level variables (ie, age, income, education, physical activity level, fruit and vegetable consumption, smoking status, drinking status, family doctor status, rural status, employment in the past 12 months and marital status) may be Caucasian important correlates of BMI within geographic regions, those variables are not capable of explaining variation in BMI between regions. Equalisation of common correlates of BMI between regions cannot be reasonably expected to reduce differences in the BMI distributions between regions. 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/

  14. Poliuretana de mamona (Ricinus communis para desvio da crista tibial no cão Polyurethane resins derived from castor oil (Ricinus communis for tibial crest deviation in dogs

    Directory of Open Access Journals (Sweden)

    Patricia Popak Maria

    2004-06-01

    Full Text Available A luxação medial de patela é uma das principais afecções ortopédicas que afetam cães de raças de pequeno porte. Tendo como princípio que o desvio da crista tibial é uma das alterações anatômicas encontradas, este estudo objetivou avaliar o efeito da poliuretana de mamona (Ricinus communis aplicada em defeitos produzidos experimentalmente na porção proximal medial da tíbia de cães normais em fase de crescimento. Para isto, foram utilizados 12 cães subdivididos aleatoriamente em 3 grupos de igual número, com mesmo tratamento, mas com análise histopatológica aos 30 (GI, 60 (GII e 90 (GIII dias. O estudo constou de avaliações clínica, radiográfica, macroscópica, histopatológica, tomográfica e análise estatística. Avaliação clínica demonstrou não haver rejeição do implante. A análise radiográfica revelou intensa reação periosteal e neoformações ósseas no local da implantação. Macroscopicamente observou-se espessamento da crista tibial, neoformações ósseas e desvio lateral da crista. Os achados à microscopia óptica revelaram presença de tecido conjuntivo fibroso ao redor da poliuretana, ausência de proliferação óssea em direção ao implante e proliferação de periósteo na face medial das tíbias. A tomografia computadorizada revelou desvio lateral da crista em 11 animais e estes desvios foram estatisticamente significantes em nível de 5% por meio do teste t pareado.Medial patellar luxation is one of the most common orthopedic problems in small breeds of dogs and tibial crest deviation is a frequent accompaining anatomical abnormality. For that reason, the purpose of this study was to evaluate the behavior of castor oil derived polyurethane implants when apllied to experimental defects created on the medial side of the proximal tibia of normal puppies. Twelve dogs were randomly divided in 3 groups of 4 animals and were submitted to the same treatment. Histopathological study was performed

  15. Enxerto autógeno de crista ilíaca na reconstrução do processo alveolar em portadores de fissura labiopalatina: estudo de 30 casos

    Directory of Open Access Journals (Sweden)

    João Luiz Carlini

    Full Text Available A reconstrução do processo alveolar em pacientes portadores de fissuras labiopalatais (FLP é fundamental para erupção de dentes permanentes e para o restabelecimento estético através de implantes osteointegrados. Assim, considerado o alto grau de reabsorção do enxerto de osso autógeno puro e triturado, optou-se no Centro de Atendimento Integral ao Fissurado Labiopalatino, Curitiba, Paraná (1997 a 1999, pelo estabelecimento de dois grupos de 15 pacientes. No primeiro, foi utilizada crista ilíaca triturada e no outro combinada com hidroxiapatita biorreabsorvível. Ao fim de seis meses, os resultados cirúrgicos foram avaliados através de radiografia periapical digital, determinando quatro linhas limites para a reconstrução óssea. A primeira linha foi traçada na região cervical do dente adjacente à fissura que apresentava menor distorção. As outras linhas foram traçadas paralelamente à linha 1, distando 3mm entre cada uma delas. O espaço entre as linhas 1 e 2 foi denominado de A, entre 2 e 3 de B e 3 e 4 de C. Para critérios de avaliação, quando o enxerto permaneceu no espaço A, foi considerado de sucesso, em contraposição aos espaços B e C, quando foram denominados de procedimentos malsucedidos. Como resultados finais, o espaço A foi constatado em 46,7% dos pacientes submetidos ao procedimento controle com crista ilíaca e 80% para o grupo experimental, quando o enxerto ósseo foi empregado conjuntamente com o material aloplástico (hidroxiapatita.

  16. Explaining dysfunctional effects of lexicographical communication

    African Journals Online (AJOL)

    user

    Explaining Dysfunctional Effects of Lexicographical Communication. 61 part of the aim.El propositions relate directly to the observability and measur- ability of aim.El. They can be taken from education theory, for instance Bloom's revised taxonomy of educational objectives (cf. Anderson and Krathwohl. 2001).21. It is now ...

  17. Your Radiologist Explains CT Colonography

    Medline Plus

    Full Text Available ... Imaging Costs Video: Abdominal Ultrasound Video: Pelvic Ultrasound Radiology and You Sponsored by Image/Video Gallery Your ... Explains CT Colonography (Virtual colonoscopy) Transcript Welcome to Radiology Info dot org! Hi, I’m Dr. Elliot ...

  18. Your Radiologist Explains Nuclear Medicine

    Medline Plus

    Full Text Available ... Imaging Costs Video: Abdominal Ultrasound Video: Pelvic Ultrasound 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 ...

  19. Your Radiologist Explains CT Colonography

    Medline Plus

    Full Text Available ... Image/Video Gallery Your Radiologist Explains CT Colonography (Virtual colonoscopy) Transcript Welcome to Radiology Info dot org! ... colonography or, as it is more commonly known, virtual colonoscopy. Virtual colonoscopy is a diagnostic imaging test ...

  20. 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 ...

  1. Your Radiologist Explains CT Colonography

    Medline Plus

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  2. Your Radiologist Explains Nuclear Medicine

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    Full Text Available ... and You Take our survey Sponsored by Image/Video Gallery Your Radiologist Explains Nuclear Medicine Transcript Welcome ... Carotid Intima-Media Thickness Test Medical Imaging Costs Video: Abdominal Ultrasound Video: Pelvic Ultrasound Radiology and You ...

  3. Your Radiologist Explains Nuclear Medicine

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    Full Text Available ... Video: Pelvic Ultrasound 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’ ...

  4. Your Radiologist Explains CT Colonography

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    Full Text Available ... Video: Pelvic Ultrasound Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains CT Colonography (Virtual ... to allow for inflation with air while CT images are being taken. If you’re scheduled for ...

  5. Your Radiologist Explains Nuclear Medicine

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    Full Text Available ... of Radiology (IDoR) 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 CT Colonography

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    Full Text Available ... Pelvic Ultrasound Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains CT Colonography (Virtual colonoscopy) ... asked to wear a gown. After the CT scan you can return to your normal diet and ...

  7. Your Radiologist Explains Nuclear Medicine

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  8. Drug detoxification dynamics explain the postantibiotic effect.

    Science.gov (United States)

    Srimani, Jaydeep K; Huang, Shuqiang; Lopatkin, Allison J; You, Lingchong

    2017-10-23

    The postantibiotic effect (PAE) refers to the temporary suppression of bacterial growth following transient antibiotic treatment. This effect has been observed for decades for a wide variety of antibiotics and microbial species. However, despite empirical observations, a mechanistic understanding of this phenomenon is lacking. Using a combination of modeling and quantitative experiments, we show that the PAE can be explained by the temporal dynamics of drug detoxification in individual cells after an antibiotic is removed from the extracellular environment. These dynamics are dictated by both the export of the antibiotic and the intracellular titration of the antibiotic by its target. This mechanism is generally applicable for antibiotics with different modes of action. We further show that efflux inhibition is effective against certain antibiotic motifs, which may help explain mixed cotreatment success. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

  9. Reconstrução do seio maxilar atrófico com enxerto autólogo de crista ilíaca: avaliação por tomografia computadorizada e radiografia panorâmica

    Directory of Open Access Journals (Sweden)

    André Luíz Zétola

    Full Text Available OBJETIVOS: As dificuldades para a utilização de implantes dentários osteointegrados em pacientes portadores de atrofia do seio maxilar justificaram o emprego de enxerto autólogo não vascularizado de crista ilíaca isolado ou associado à hidroxiapatita (HA em 14 pacientes submetidos a 25 procedimentos no Hospital das Nações, Curitiba, Paraná, portadores de atrofia do sinus maxilar. O objetivo foi avaliar comparativamente a precisão da tomografia computadorizada e da radiografia panorâmica, através da quantificação da neoformação óssea nesta estrutura. MÉTODOS: Foram selecionadas pacientes edentados, com altura óssea residual do rebordo gengival ao soalho do seio maxilar menor que 5mm. O enxerto medular de crista ilíaca fragmentada isolado ou misturado com HA foi colocado através da parede lateral no soalho atrófico da cuba maxilar por via submucosa. A avaliação quantitativa e qualitativa foi feita através da radiografia panorâmica e tomografia computadorizada, sendo utilizado na análise estatística a distribuição t de Student (prevalência de 0,05 para análise das variâncias, considerado que a leitura dos laudos radiológicos foi feita por dois especialistas, medindo a distância entre os pontos inferiores e superiores do enxerto no soalho do seio maxilar. RESULTADOS: Tivemos um ganho médio de 14,8mm em todos os procedimentos, com um erro maior que 3mm em 16 procedimentos (64% e incorporação satisfatória do enxerto ósseo suficiente para futuro implante dentário. CONCLUSÕES: A tomografia computadorizada foi o método de escolha na avaliação qualitativa e quantitativa da incorporação de enxerto autólogo não vascularizado em seio maxilar atrófico.

  10. Explaining Errors in Children's Questions

    Science.gov (United States)

    Rowland, Caroline F.

    2007-01-01

    The ability to explain the occurrence of errors in children's speech is an essential component of successful theories of language acquisition. The present study tested some generativist and constructivist predictions about error on the questions produced by ten English-learning children between 2 and 5 years of age. The analyses demonstrated that,…

  11. Your Radiologist Explains Nuclear Medicine

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  12. Your Radiologist Explains CT Colonography

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  13. Your Radiologist Explains Nuclear Medicine

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  14. Your Radiologist Explains CT Colonography

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  15. Explaining the gender wealth gap.

    Science.gov (United States)

    Ruel, Erin; Hauser, Robert M

    2013-08-01

    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 between 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. After controlling for the full model, we find that a gender wealth gap remains between married men and women that we speculate may be related to gender differences in investment strategies and selection effects.

  16. 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...

  17. Explaining (Missing) Regulator Paradigm Shifts

    DEFF Research Database (Denmark)

    Wigger, Angela; Buch-Hansen, Hubert

    2014-01-01

    of competition regulation is heaving into sight. It sets out to explain this from the vantage point of a critical political economy perspective, which identifies the circumstances under which a crisis can result in a regulatory paradigm shift. Contrasting the current situation with the shift in EC/EU competition...... capitalism; the social power configuration underpinning the neoliberal order remains unaltered; no clear counter-project has surfaced; the European Commission has been (and remains) in a position to oppose radical changes; and finally, there are no signs of a wider paradigm shift in the EU's regulatory...

  18. Explaining the Gender Wealth Gap

    OpenAIRE

    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...

  19. What explains consciousness? Or…What consciousness explains?

    Science.gov (United States)

    Dulany, Donelson E

    2014-01-01

    In this invited commentary I focus on the topic addressed in three papers: De Sousa's (2013[1617]) Toward an Integrative Theory of Consciousness, a monograph with Parts 1 & 2, as well as commentaries by Pereira (2013a[59]) and Hirstein (2013[42]). All three are impressively scholarly and can stand-and shout-on their own. But theory of consciousness? My aim is to slice that topic into the two fundamentally different kinds of theories of consciousness, say what appears to be an ideology, out of behaviourism into cognitivism, now also influencing the quest for an "explanation of consciousness" in cognitive neuroscience. I will then say what can be expected given what we know of the complexity of brain structure, the richness of a conscious "vocabulary", and current technological limits of brain imaging. This will then turn to the strategy for examining "what consciousness explains"-metatheory, theories, mappings, and a methodology of competitive support, a methodology especially important where there are competing commitments. There are also increasingly common identifications of methodological bias in, along with failures to replicate, studies reporting unconscious controls in decision, social priming-as there have been in perception, learning, problem solving, etc. The literature critique has provided evidence taken as reducing, and in some cases eliminating, a role for conscious controls-a position consistent with that ideology out of behaviourism into cognitivism. It is an ideological position that fails to recognize the fundamental distinction between theoretical and metaphysical assertions.

  20. 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.

    2012-04-01

    Recently, Breneman et al. (2011) reported observations of large amplitude lightning and transmitter whistler mode waves from two STEREO passes through the inner radiation belt (L plane transverse to the magnetic field showed that the transmitter waves underwent periodic polarization reversals. Specifically, their polarization would cycle through a pattern of right-hand to linear to left-hand polarization at a rate of roughly 200 Hz. The lightning whistlers were observed to be left-hand polarized at frequencies greater than the lower hybrid frequency and less than the transmitter frequency (21.4 kHz) and right-hand polarized otherwise. Only right-hand polarized waves in the inner radiation belt should exist in the frequency range of the whistler mode and these reversals were not explained in the previous paper. 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 (1984) 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. (2008).

  1. 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 (Lwaves underwent periodic polarization reversals. Specifically, their polarization would cycle through a pattern of right-hand to linear to left-hand polarization at a rate of roughly 200 Hz. The lightning whistlers were observed to be left-hand polarized at frequencies greater than the lower hybrid frequency and less than the transmitter frequency (21.4 kHz) and right-hand polarized otherwise. Only righthand polarized waves in the inner radiation belt should exist in the frequency range of the whistler mode and these reversals were not explained in the previous paper. 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.

  2. 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.

  3. 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

  4. Dissipative dark matter explains rotation curves

    Science.gov (United States)

    Foot, R.

    2015-06-01

    Dissipative dark matter, where dark matter particles interact with a massless (or very light) boson, is studied. Such dark matter can arise in simple hidden sector gauge models, including those featuring an unbroken U (1 )' gauge symmetry, leading to a dark photon. Previous work has shown that such models can not only explain the large scale structure and cosmic microwave background, but potentially also dark matter phenomena on small scales, such as the inferred cored structure of dark matter halos. In this picture, dark matter halos of disk galaxies not only cool via dissipative interactions but are also heated via ordinary supernovae (facilitated by an assumed photon-dark photon kinetic mixing interaction). This interaction between the dark matter halo and ordinary baryons, a very special feature of these types of models, plays a critical role in governing the physical properties of the dark matter halo. Here, we further study the implications of this type of dissipative dark matter for disk galaxies. Building on earlier work, we develop a simple formalism which aims to describe the effects of dissipative dark matter in a fairly model independent way. This formalism is then applied to generic disk galaxies. We also consider specific examples, including NGC 1560 and a sample of dwarf galaxies from the LITTLE THINGS survey. We find that dissipative dark matter, as developed here, does a fairly good job accounting for the rotation curves of the galaxies considered. Not only does dissipative dark matter explain the linear rise of the rotational velocity of dwarf galaxies at small radii, but it can also explain the observed wiggles in rotation curves which are known to be correlated with corresponding features in the disk gas distribution.

  5. 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...

  6. 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...

  7. Explaining Biological Functionality: Is Control Theory Enough ...

    African Journals Online (AJOL)

    It is generally agreed that organisms are Complex Adaptive Systems. Since the rise of Cybernetics in the middle of the last century ideas from information theory and control theory have been applied to the adaptations of biological organisms in order to explain how they work. This does not, however, explain functionality, ...

  8. 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

  9. 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

  10. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... Imaging Costs Video: Abdominal Ultrasound Video: Pelvic Ultrasound 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 ...

  11. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... Lung Cancer Awareness Month Recently posted: Carotid Intima-Media Thickness Test Medical Imaging Costs Video: Abdominal Ultrasound Video: Pelvic Ultrasound Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography ( ...

  12. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... Video: Pelvic Ultrasound Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography ( ... pictures of the major blood vessels throughout your body. It may be performed with or without contrast ...

  13. 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.

  14. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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

  15. 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

  16. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... and You Take our survey Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) ... Carotid Intima-Media Thickness Test Medical Imaging Costs Video: Abdominal Ultrasound Video: Pelvic Ultrasound Radiology and You ...

  17. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... Index A-Z Spotlight Recently posted: Carotid Intima-Media Thickness Test Medical Imaging Costs Video: Abdominal Ultrasound Video: Pelvic Ultrasound Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography ( ...

  18. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... of Radiology (IDoR) Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography ( ... pictures of the major blood vessels throughout your body. It may be performed with or without contrast ...

  19. Observing participating observation

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    2010-01-01

    Current methodology concerning participating observation in general leaves the act of observation unobserved. Approaching participating observation from systems theory offers fundamental new insights into the topic. Observation is always participation. There is no way to escape becoming a partici......Current methodology concerning participating observation in general leaves the act of observation unobserved. Approaching participating observation from systems theory offers fundamental new insights into the topic. Observation is always participation. There is no way to escape becoming...... as the idea of the naïve observer becomes a void. Not recognizing and observing oneself as observer and co-producer of empirical data simply leaves the process of observation as the major unobserved absorber of contingency in data production based on participating observation....

  20. Observing participating observation

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    2011-01-01

    Current methodology concerning participating observation in general leaves the act of observation unobserved. Approaching participating observation from systems theory offers fundamental new insights into the topic. Observation is always participation. There is no way to escape becoming a partici......Current methodology concerning participating observation in general leaves the act of observation unobserved. Approaching participating observation from systems theory offers fundamental new insights into the topic. Observation is always participation. There is no way to escape becoming...... as the idea of the naïve observer becomes a void. Not recognizing and observing oneself as observer and co-producer of empirical data simply leaves the process of observation as the major unobserved absorber of contingency in data production based on participating observation....

  1. Learning to apply models of materials while explaining their properties

    Science.gov (United States)

    Karpin, Tiia; Juuti, Kalle; Lavonen, Jari

    2014-09-01

    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. Sample:An experimental group is 27 Finnish upper secondary school students and control group included 18 students from the same school. Design and methods:In quasi-experimental setting, students were guided through predict, observe, explain activities in four practical work situations. It was intended that the structural models would encourage students to learn how to identify and apply appropriate models when predicting and explaining situations. The lessons, organised over a one-week period, began with a teacher's demonstration and continued with student experiments in which they described the properties and behaviours of six household products representing three different materials. Results:Most students in the experimental group learned to apply the models correctly, as demonstrated by post-test scores that were significantly higher than pre-test scores. The control group showed no significant difference between pre- and post-test scores. Conclusions:The findings indicate that the intervention where students engage in predict, observe, explain activities while several materials and models are confronted at the same time, had a positive effect on learning outcomes.

  2. 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.

  3. Explaining religiosity: towards a unified theoretical model.

    Science.gov (United States)

    Stolz, Jörg

    2009-06-01

    The article presents a unified theoretical model, explaining differences in Christian and 'alternative' religiosity at individual and collective levels. The model reconstructs and integrates the most important theories explaining religiosity (deprivation, regulation, socialization, cultural production, and ethnicity) as complementary causal mechanisms in a rational-action based framework. It is maintained that the mechanisms of the various theories are not exclusive, but complementary, and that integration into the general model is both theoretically and empirically beneficial. The model is tested on representative data from Switzerland. Substantively, I find for the Swiss case that Christian religiosity can be best explained by a religious socialization mechanism. The most important mechanisms accounting for alternative religiosity involve deprivation, gender, and age.

  4. Climate variation explains a third of global crop yield variability.

    Science.gov (United States)

    Ray, Deepak K; Gerber, James S; MacDonald, Graham K; West, Paul C

    2015-01-22

    Many studies have examined the role of mean climate change in agriculture, but an understanding of the influence of inter-annual climate variations on crop yields in different regions remains elusive. We use detailed crop statistics time series for ~13,500 political units to examine how recent climate variability led to variations in maize, rice, wheat and soybean crop yields worldwide. While some areas show no significant influence of climate variability, in substantial areas of the global breadbaskets, >60% of the yield variability can be explained by climate variability. Globally, climate variability accounts for roughly a third (~32-39%) of the observed yield variability. Our study uniquely illustrates spatial patterns in the relationship between climate variability and crop yield variability, highlighting where variations in temperature, precipitation or their interaction explain yield variability. We discuss key drivers for the observed variations to target further research and policy interventions geared towards buffering future crop production from climate variability.

  5. Buzz Factor or Innovation Potential: What Explains Cryptocurrencies? Returns?

    OpenAIRE

    Wang, Sha; Vergne, Jean-Philippe

    2017-01-01

    Cryptocurrencies have become increasingly popular since the introduction of bitcoin in 2009. In this paper, we identify factors associated with variations in cryptocurrencies? market values. In the past, researchers argued that the ?buzz? surrounding cryptocurrencies in online media explained their price variations. But this observation obfuscates the notion that cryptocurrencies, unlike fiat currencies, are technologies entailing a true innovation potential. By using, for the first time, a u...

  6. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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  7. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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    Full Text Available ... Recently posted: Carotid Intima-Media Thickness Test Medical Imaging Costs Video: Abdominal Ultrasound Video: Pelvic Ultrasound Radiology and You Take our survey Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot ...

  8. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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

  9. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Science.gov (United States)

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

  10. 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 ...

  11. Explaining the Sex Difference in Dyslexia

    Science.gov (United States)

    Arnett, Anne B.; Pennington, Bruce F.; Peterson, Robin L.; Willcutt, Erik G.; DeFries, John C.; Olson, Richard K.

    2017-01-01

    Background: Males are diagnosed with dyslexia more frequently than females, even in epidemiological samples. This may be explained by greater variance in males' reading performance. Methods: We expand on previous research by rigorously testing the variance difference theory, and testing for mediation of the sex difference by cognitive correlates.…

  12. 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…

  13. How Employees Remain Happy: Explaining a Paradox

    Science.gov (United States)

    Hutton, Dorothy M.; Atkinson, Barbara; Judd, Priya; Darling, Julie; Tran, Linh; Cummins, Robert A.

    2004-01-01

    This paper draws on subjective quality of life theory to explain findings from three studies of quality of work life. The studies were conducted with 346 regional process workers, metropolitan employment officers and nurses. The results support the adoption of the theory of homeostasis as an explanation for findings on subjective wellbeing at work…

  14. 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...

  15. 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

  16. Explaining quality of life with crisis theory

    NARCIS (Netherlands)

    Sprangers, M.A.G.; van den Heuvel, W.J.A.; de Haes, H.C.J.M.

    2002-01-01

    Based on the premises of crisis theory. we expected cancer patients in-crisis to report a poorer quality of life (QL) and cancer patients post-crisis to report a similar level of overall QL in comparison to healthy individuals. To explain these hypothesized findings, we expected the coping resources

  17. Your Radiologist Explains Magnetic Resonance Angiography (MRA)

    Medline Plus

    Full Text Available ... Radiology (IDoR) Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) ... Carotid Intima-Media Thickness Test Medical Imaging Costs Video: Abdominal Ultrasound Video: Pelvic Ultrasound November 8 is ...

  18. Conventional forces can explain the anomalous acceleration of Pioneer 10

    Science.gov (United States)

    Scheffer, Louis K.

    2003-04-01

    Anderson et al. find the measured trajectories of Pioneer 10 and 11 spacecrafts deviate from the trajectories computed from known forces acting on them. This unmodeled acceleration (and the less well known, but similar, unmodeled torque) can be accounted for by non-isotropic radiation of spacecraft heat. Various forms of non-isotropic radiation were proposed by Katz, Murphy, and Scheffer, but Anderson et al. felt that none of these could explain the observed effect. This paper calculates the known effects in more detail and considers new sources of radiation, all based on spacecraft construction. These effects are then modeled over the duration of the experiment. The model reproduces the acceleration from its appearance at a heliocentric distance of 5 AU to the last measurement at 71 AU to within 10%. However, it predicts a larger decrease in acceleration between intervals I and III of the Pioneer 10 observations than is observed. This is a 2σ discrepancy from the average of the three analyses (SIGMA, CHASMP, and Markwardt). A more complex (but more speculative) model provides a somewhat better fit. Radiation forces can also plausibly explain the previously unmodeled torques, including the spindown of Pioneer 10 that is directly proportional to spacecraft bus heat, and the slow but constant spin-up of Pioneer 11. In any case, by accounting for the bulk of the acceleration, the proposed mechanism makes it much more likely that the entire effect can be explained without the need for new physics.

  19. 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.

  20. 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.

  1. 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...

  2. John Watson's paradoxical struggle to explain Freud.

    Science.gov (United States)

    Rilling, M

    2000-03-01

    John Watson was fascinated by the discoveries of psychoanalysis, but he rejected Freud's central concept of the unconscious as incompatible with behaviorism. After failing to explain psychoanalysis in terms of William James's concept of habit, Watson borrowed concepts from classical conditioning to explain Freud's discoveries. Watson's famous experiment with Little Albert is interpreted not only in the context of Pavlovian conditioning but also as a psychoanalytically inspired attempt to capture simplified analogues of adult phobic behavior, including the "transference" of emotion in an infant. Watson used his behavioristic concept of conditioned emotional responses to compete with Freud's concepts of displacement and the unconscious transference of emotion. Behind a mask of anti-Freudian bias, Watson surprisingly emerges as a psychologist who popularized Freud and pioneered the scientific appraisal of his ideas in the laboratory.

  3. Explaining Underrepresentation: A Theory of Precluded Interest.

    Science.gov (United States)

    Cheryan, Sapna; Plaut, Victoria C

    2010-10-01

    What processes best explain women's underrepresentation in science, math, and engineering fields in the U.S.? Do they also explain men's underrepresentation in the humanities? Two survey studies across two U.S. West Coast universities (N = 62; N = 614) addressed these questions in the context of two fields: one male-dominated (computer science) and the other female-dominated (English). Among a set of social predictors-including perceived similarity to the people in the field, social identity threats, and expectations of success-the best mediator of women's lower interest in computer science and men's lower interest in English was perceived similarity. Thus, changing students' social perceptions of how they relate to those in the field may help to diversify academic fields.

  4. 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

  5. Explaining the Slowdown in Global Trade

    OpenAIRE

    Jarkko Jaaskela; Thomas Mathews

    2015-01-01

    Following the global financial crisis, global trade contracted sharply and, after an initial recovery, grew at an unusually slow pace relative to global GDP. This article reviews cyclical and structural explanations for this phenomenon, and finds econometric evidence that cyclical factors – namely shifts in the composition of aggregate demand toward less import-intensive components and heightened economic uncertainty – can explain most of the slowdown in trade in a panel of advanced economies...

  6. "Explaining the Gender Wage Gap in Georgia"

    OpenAIRE

    Khitarishvili, Tamar

    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...

  7. Explaining the variety of human sexuality.

    Science.gov (United States)

    FitzGerald, W A

    2000-11-01

    In this paper, the author formulates a theory to explain why human sexual orientation seems to run amok. The 'psychic instrument', as he terms it, is the baby's dreaming mind which interprets or misinterprets input from its sociocultural sexual environment. The baby, already born an omnisexual being, then develops a fantasy life with socially sanctioned or unsanctioned fetishes which are likely to be expressed when certain triggering situations arise.

  8. 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.

  9. 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.

  10. word2vec Parameter Learning Explained

    OpenAIRE

    Rong, Xin

    2014-01-01

    The word2vec model and application by Mikolov et al. have attracted a great amount of attention in recent two years. The vector representations of words learned by word2vec models have been shown to carry semantic meanings and are useful in various NLP tasks. As an increasing number of researchers would like to experiment with word2vec or similar techniques, I notice that there lacks a material that comprehensively explains the parameter learning process of word embedding models in details, t...

  11. Chromosome congression explained by nanoscale electrostatics.

    Science.gov (United States)

    Gagliardi, L John; Shain, Daniel H

    2014-02-24

    Nanoscale electrostatic microtubule disassembly forces between positively charged molecules in kinetochores and negative charges on plus ends of microtubules have been implicated in poleward chromosome motions and may also contribute to antipoleward chromosome movements. We propose that chromosome congression can be understood in terms of antipoleward nanoscale electrostatic microtubule assembly forces between negatively charged microtubule plus ends and like-charged chromosome arms, acting in conjunction with poleward microtubule disassembly forces. Several other aspects of post-attachment prometaphase chromosome motions, as well as metaphase oscillations, are consistently explained within this framework.

  12. Explaining perceptions of the unemployed in Europe

    OpenAIRE

    Vlandas, Tim

    2016-01-01

    This article explores the determinants of the perceptions of the unemployed in 29 European countries along three dimensions: whether people see the unemployed as the ‘government’s responsibility’; whether they believe the unemployed do not ‘try hard to find a job’; and whether they think that the standard of living of the unemployed is ‘bad’. I derive a number of expectations from the political economy literature on policy preferences and test whether these expectations explain variation in t...

  13. 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.

  14. Developmental systems theory: what does it explain, and how does it explain it?

    Science.gov (United States)

    Griffiths, Paul E; Tabery, James

    2013-01-01

    We examine developmental systems theory (DST) with two questions in mind: What does DST explain? How does DST explain it? To answer these questions, we start by reviewing major contributions to the origins of DST: the introduction of the idea of a "developmental system", the idea of probabilistic epigenesis, the attention to the role of information in the developmental system, and finally the explicit identification of a DST. We then consider what DST is not, contrasting it with two approaches that have been foils for DST: behavioral genetics and nativist cognitive psychology. Third, we distill out two core concepts that have defined DSTthroughout its history: epigenesis and developmental dynamics. Finally, we turn to how DST explains, arguing that it explains by elucidating mechanisms.

  15. Social inheritance can explain the structure of animal social networks

    Science.gov (United States)

    Ilany, Amiyaal; Akçay, Erol

    2016-01-01

    The social network structure of animal populations has major implications for survival, reproductive success, sexual selection and pathogen transmission of individuals. But as of yet, no general theory of social network structure exists that can explain the diversity of social networks observed in nature, and serve as a null model for detecting species and population-specific factors. Here we propose a simple and generally applicable model of social network structure. We consider the emergence of network structure as a result of social inheritance, in which newborns are likely to bond with maternal contacts, and via forming bonds randomly. We compare model output with data from several species, showing that it can generate networks with properties such as those observed in real social systems. Our model demonstrates that important observed properties of social networks, including heritability of network position or assortative associations, can be understood as consequences of social inheritance. PMID:27352101

  16. Social inheritance can explain the structure of animal social networks.

    Science.gov (United States)

    Ilany, Amiyaal; Akçay, Erol

    2016-06-28

    The social network structure of animal populations has major implications for survival, reproductive success, sexual selection and pathogen transmission of individuals. But as of yet, no general theory of social network structure exists that can explain the diversity of social networks observed in nature, and serve as a null model for detecting species and population-specific factors. Here we propose a simple and generally applicable model of social network structure. We consider the emergence of network structure as a result of social inheritance, in which newborns are likely to bond with maternal contacts, and via forming bonds randomly. We compare model output with data from several species, showing that it can generate networks with properties such as those observed in real social systems. Our model demonstrates that important observed properties of social networks, including heritability of network position or assortative associations, can be understood as consequences of social inheritance.

  17. Boosted Regression Tree Models to Explain Watershed ...

    Science.gov (United States)

    Boosted regression tree (BRT) models were developed to quantify the nonlinear relationships between landscape variables and nutrient concentrations in a mesoscale mixed land cover watershed during base-flow conditions. Factors that affect instream biological components, based on the Index of Biotic Integrity (IBI), were also analyzed. Seasonal BRT models at two spatial scales (watershed and riparian buffered area [RBA]) for nitrite-nitrate (NO2-NO3), total Kjeldahl nitrogen, and total phosphorus (TP) and annual models for the IBI score were developed. Two primary factors — location within the watershed (i.e., geographic position, stream order, and distance to a downstream confluence) and percentage of urban land cover (both scales) — emerged as important predictor variables. Latitude and longitude interacted with other factors to explain the variability in summer NO2-NO3 concentrations and IBI scores. BRT results also suggested that location might be associated with indicators of sources (e.g., land cover), runoff potential (e.g., soil and topographic factors), and processes not easily represented by spatial data indicators. Runoff indicators (e.g., Hydrological Soil Group D and Topographic Wetness Indices) explained a substantial portion of the variability in nutrient concentrations as did point sources for TP in the summer months. The results from our BRT approach can help prioritize areas for nutrient management in mixed-use and heavily impacted watershed

  18. 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 )}}.

  19. Blazar spectral variability as explained by a twisted inhomogeneous jet.

    Science.gov (United States)

    Raiteri, C M; Villata, M; Acosta-Pulido, J A; Agudo, I; Arkharov, A A; Bachev, R; Baida, G V; Benítez, E; Borman, G A; Boschin, W; Bozhilov, V; Butuzova, M S; Calcidese, P; Carnerero, M I; Carosati, D; Casadio, C; Castro-Segura, N; Chen, W-P; Damljanovic, G; D'Ammando, F; Di Paola, A; Echevarría, J; Efimova, N V; Ehgamberdiev, Sh A; Espinosa, C; Fuentes, A; Giunta, A; Gómez, J L; Grishina, T S; Gurwell, M A; Hiriart, D; Jermak, H; Jordan, B; Jorstad, S G; Joshi, M; Kopatskaya, E N; Kuratov, K; Kurtanidze, O M; Kurtanidze, S O; Lähteenmäki, A; Larionov, V M; Larionova, E G; Larionova, L V; Lázaro, C; Lin, C S; Malmrose, M P; Marscher, A P; Matsumoto, K; McBreen, B; Michel, R; Mihov, B; Minev, M; Mirzaqulov, D O; Mokrushina, A A; Molina, S N; Moody, J W; Morozova, D A; Nazarov, S V; Nikolashvili, M G; Ohlert, J M; Okhmat, D N; Ovcharov, E; Pinna, F; Polakis, T A; Protasio, C; Pursimo, T; Redondo-Lorenzo, F J; Rizzi, N; Rodriguez-Coira, G; Sadakane, K; Sadun, A C; Samal, M R; Savchenko, S S; Semkov, E; Skiff, B A; Slavcheva-Mihova, L; Smith, P S; Steele, I A; Strigachev, A; Tammi, J; Thum, C; Tornikoski, M; Troitskaya, Yu V; Troitsky, I S; Vasilyev, A A; Vince, O

    2017-12-21

    Blazars are active galactic nuclei, which are powerful sources of radiation whose central engine is located in the core of the host galaxy. Blazar emission is dominated by non-thermal radiation from a jet that moves relativistically towards us, and therefore undergoes Doppler beaming. This beaming causes flux enhancement and contraction of the variability timescales, so that most blazars appear as luminous sources characterized by noticeable and fast changes in brightness at all frequencies. The mechanism that produces this unpredictable variability is under debate, but proposed mechanisms include injection, acceleration and cooling of particles, with possible intervention of shock waves or turbulence. Changes in the viewing angle of the observed emitting knots or jet regions have also been suggested as an explanation of flaring events and can also explain specific properties of blazar emission, such as intra-day variability, quasi-periodicity and the delay of radio flux variations relative to optical changes. Such a geometric interpretation, however, is not universally accepted because alternative explanations based on changes in physical conditions-such as the size and speed of the emitting zone, the magnetic field, the number of emitting particles and their energy distribution-can explain snapshots of the spectral behaviour of blazars in many cases. Here we report the results of optical-to-radio-wavelength monitoring of the blazar CTA 102 and show that the observed long-term trends of the flux and spectral variability are best explained by an inhomogeneous, curved jet that undergoes changes in orientation over time. We propose that magnetohydrodynamic instabilities or rotation of the twisted jet cause different jet regions to change their orientation and hence their relative Doppler factors. In particular, the extreme optical outburst of 2016-2017 (brightness increase of six magnitudes) occurred when the corresponding emitting region had a small viewing angle

  20. Can chunk size differences explain developmental changes in lexical learning?

    Directory of Open Access Journals (Sweden)

    Eleonore H.M. Smalle

    2016-01-01

    Full Text Available In three experiments, we investigated Hebb repetition learning (HRL differences between children and adults, as a function of the type of item (lexical vs. sub-lexical and the level of item-overlap between sequences. In a first experiment, it was shown that when non-repeating and repeating (Hebb sequences of words were all permutations of the same words, HRL was slower than when the sequences shared no words. This item-overlap effect was observed in both children and adults. In a second experiment, we used syllable sequences and we observed reduced HRL due to item-overlap only in children. The findings are explained within a chunking account of the HRL effect on the basis of which we hypothesize that children, compared with adults, chunk syllable sequences in smaller units. By hypothesis, small chunks are more prone to interference from anagram representations included in the filler sequences, potentially explaining the item-overlap effect in children. This hypothesis was tested in a third experiment with adults where we experimentally manipulated the chunk size by embedding pauses in the syllable sequences. Interestingly, we showed that imposing a small chunk size caused adults to show the same behavioral effects as those observed in children. Departing from the analogy between verbal HRL and lexical development, the results are discussed in light of the less-is-more hypothesis of age-related differences in language acquisition.

  1. Can Chunk Size Differences Explain Developmental Changes in Lexical Learning?

    Science.gov (United States)

    Smalle, Eleonore H M; Bogaerts, Louisa; Simonis, Morgane; Duyck, Wouter; Page, Michael P A; Edwards, Martin G; Szmalec, Arnaud

    2015-01-01

    In three experiments, we investigated Hebb repetition learning (HRL) differences between children and adults, as a function of the type of item (lexical vs. sub-lexical) and the level of item-overlap between sequences. In a first experiment, it was shown that when non-repeating and repeating (Hebb) sequences of words were all permutations of the same words, HRL was slower than when the sequences shared no words. This item-overlap effect was observed in both children and adults. In a second experiment, we used syllable sequences and we observed reduced HRL due to item-overlap only in children. The findings are explained within a chunking account of the HRL effect on the basis of which we hypothesize that children, compared with adults, chunk syllable sequences in smaller units. By hypothesis, small chunks are more prone to interference from anagram representations included in the filler sequences, potentially explaining the item-overlap effect in children. This hypothesis was tested in a third experiment with adults where we experimentally manipulated the chunk size by embedding pauses in the syllable sequences. Interestingly, we showed that imposing a small chunk size caused adults to show the same behavioral effects as those observed in children. Departing from the analogy between verbal HRL and lexical development, the results are discussed in light of the less-is-more hypothesis of age-related differences in language acquisition.

  2. Localized bedrock aquifer distribution explains discharge from a headwater catchment

    Science.gov (United States)

    Kosugi, Ken'ichirou; Fujimoto, Masamitsu; Katsura, Shin'ya; Kato, Hiroyuki; Sando, Yoshiki; Mizuyama, Takahisa

    2011-07-01

    Understanding a discharge hydrograph is one of the leading interests in catchment hydrology. Recent research has provided credible information on the importance of bedrock groundwater on discharge hydrographs from headwater catchments. However, intensive monitoring of bedrock groundwater is rare in mountains with steep topography. Hence, how bedrock groundwater controls discharge from a steep headwater catchment is in dispute. In this study, we conducted long-term hydrological observations using densely located bedrock wells in a headwater catchment underlain by granitic bedrock. The catchment has steep topography affected by diastrophic activities. Results showed a fairly regionalized distribution of bedrock aquifers within a scale of tens of meters, consisting of upper, middle, and lower aquifers, instead of a gradual and continuous decline in water level from ridge to valley bottom. This was presumably attributable to the unique bedrock structure; fault lines developed in the watershed worked to form divides between the bedrock aquifers. Spatial expanse of each aquifer and the interaction among aquifers were key factors to explain gentle and considerable variations in the base flow discharge and triple-peak discharge responses of the observed hydrograph. A simple model was developed to simulate the discharge hydrograph, which computed each of the contributions from the soil mantle groundwater, from the lower aquifer, and from the middle aquifer to the discharge. The modeling results generally succeeded in reproducing the observed hydrograph. Thus, this study demonstrated that understanding regionalized bedrock aquifer distribution is pivotal for explaining discharge hydrograph from headwater catchments that have been affected by diastrophic activities.

  3. Mitochondrial dysfunction may explain the cardiomyopathy of chronic iron overload.

    Science.gov (United States)

    Gao, Xueshan; Qian, Mingwei; Campian, Jian Li; Marshall, James; Zhou, Zhanxiang; Roberts, Andrew M; Kang, Y James; Prabhu, Sumanth D; Sun, Xiao-Feng; Eaton, John W

    2010-08-01

    In patients with hemochromatosis, cardiac dysfunction may appear years after they have reached a state of iron overload. We hypothesized that cumulative iron-catalyzed oxidant damage to mitochondrial DNA (mtDNA) might explain the cardiomyopathy of chronic iron overload. Mice were given repetitive injections of iron dextran for a total of 4weeks after which the iron-loaded mice had elevated cardiac iron, modest cardiac hypertrophy, and cardiac dysfunction. qPCR amplification of near-full-length ( approximately 16kb) mtDNA revealed >50% loss of full-length product, whereas amounts of a qPCR product of a nuclear gene (13kb region of beta globin) were unaffected. Quantitative rtPCR analyses revealed 60-70% loss of mRNA for proteins encoded by mtDNA with no change in mRNA abundance for nuclear-encoded respiratory subunits. These changes coincided with proportionate reductions in complex I and IV activities and decreased respiration of isolated cardiac mitochondria. We conclude that chronic iron overload leads to cumulative iron-mediated damage to mtDNA and impaired synthesis of mitochondrial respiratory chain subunits. The resulting respiratory dysfunction may explain the slow development of cardiomyopathy in chronic iron overload and similar accumulation of damage to mtDNA may also explain the mitochondrial dysfunction observed in slowly progressing diseases such as neurodegenerative disorders. Copyright 2010 Elsevier Inc. All rights reserved.

  4. Factors explaining children's responses to intravenous needle insertions.

    Science.gov (United States)

    McCarthy, Ann Marie; Kleiber, Charmaine; Hanrahan, Kirsten; Zimmerman, M Bridget; Westhus, Nina; Allen, Susan

    2010-01-01

    Previous research shows that numerous child, parent, and procedural variables affect children's distress responses to procedures. Cognitive-behavioral interventions such as distraction are effective in reducing pain and distress for many children undergoing these procedures. The purpose of this report was to examine child, parent, and procedural variables that explain child distress during a scheduled intravenous insertion when parents are distraction coaches for their children. A total of 542 children, between 4 and 10 years of age, and their parents participated. Child age, gender, diagnosis, and ethnicity were measured by questions developed for this study. Standardized instruments were used to measure child experience with procedures, temperament, ability to attend, anxiety, coping style, and pain sensitivity. Questions were developed to measure parent variables, including ethnicity, gender, previous experiences, and expectations, and procedural variables, including use of topical anesthetics and difficulty of procedure. Standardized instruments were used to measure parenting style and parent anxiety, whereas a new instrument was developed to measure parent performance of distraction. Children's distress responses were measured with the Observation Scale of Behavioral Distress-Revised (behavioral), salivary cortisol (biological), Oucher Pain Scale (self-report), and parent report of child distress (parent report). Regression methods were used for data analyses. Variables explaining behavioral, child-report and parent-report measures include child age, typical coping response, and parent expectation of distress (p parents' distraction coaching explained a significant portion of behavioral, biological, and parent-report distress measures (p parent distraction coaching.

  5. Alcohol and breast cancer: the mechanisms explained.

    Science.gov (United States)

    Al-Sader, Hassen; Abdul-Jabar, Hani; Allawi, Zahra; Haba, Yasser

    2009-08-01

    Breast cancer is a leading cause of death amongst women, several studies have shown significant association between alcohol consumption and breast cancer. The aim of this overview is to highlight some of the mechanisms by which alcohol consumption could increase the risk of developing breast cancer. Using online Medline search engine, article containing details about mechanisms which explain the link between alcohol and breast cancer were examined. A number of mechanisms were found by which alcohol could increase the risk of breast cancer, alcohol's interaction and effect on oestrogen secretion; number of oestrogen receptors; the generation of acetaldehyde and hydroxyl free radicals; cells migration and metastasis; secretion of IGF1 and interaction with HRT and folate metabolism. In conclusion, it is essential for clinicians to understand these mechanisms and inform patients of the link between alcohol and breast cancer. Breast cancer; Alcohol; Mechanisms.

  6. 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.

  7. 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.

  8. Can molecular cell biology explain chromosome motions?

    Science.gov (United States)

    Shain, Daniel H; Gagliardi, L John

    2011-05-27

    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. 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. 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. © 2011 Shain and Gagliardi; licensee BioMed Central Ltd.

  9. 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

    BACKGROUND: The offer of prenatal Down's syndrome screening is part of routine antenatal care in most of Europe; however screening uptake varies significantly across countries. Although a decision to accept or reject screening is a personal choice, it is unlikely that the widely differing uptake...... rates across countries can be explained by variation in individual values alone.The aim of this study was to compare Down's syndrome screening policies and programmes in the Netherlands, where uptake is relatively low ( 90% respectively....... 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...

  10. Training science centre Explainers. The Techniquest experience

    Directory of Open Access Journals (Sweden)

    Colin Johnson

    2005-12-01

    Full Text Available Techniquest was established in 1986, and in 1995 moved to its current premises at Cardiff Bay, South Wales. This was the first purpose-built science centre in the UK. It receives around 200,000 visitors every year to its exhibition, and to its programmes for schools and public audiences in the theatre, laboratory, discovery room and planetarium. The author joined the Techniquest project in 1985, became a staff member in 1990 and was the Chief Executive from 1997 until his retirement in 2004. Techniquest has three “out-stations” in Wales, and is responsible for the supply and maintenance of exhibits to the Look Out Discovery Centre in Bracknell, England. There is a Techniquest gallery at the Lisbon Pavilhão do Conhecimento - Ciência Viva, and a traveling exhibition, SciQuest, in South Africa which was also supplied by Techniquest. All these centres rely on the effective intervention of “Explainers” (at Techniquest we call them “Helpers” to provide the best possible experience for visitors. At its most demanding, the tasks of an Explainer are varied and intensive, yet there may be times when the duties are mundane or even dull. When you rely on people to act as both hosts and housekeepers, to provide both support and stimulus, and to be both welcoming and watchful, you are asking a great deal. This article raises some of the issues concerned with the recruitment and retention of Explainers, their training and management, and the way in which their role is recognized and valued by the science centre as a whole.

  11. Transitioning from Idiopathic to Explainable Autoimmune Hepatitis.

    Science.gov (United States)

    Czaja, Albert J

    2015-10-01

    Autoimmune hepatitis lacks an identifiable cause, and its diagnosis requires the exclusion of etiologically defined diseases that resemble it. Insights into its pathogenesis are moving autoimmune hepatitis from an idiopathic to explainable disease, and the goal of this review is to describe the insights that are hastening this transition. Two types of autoimmune hepatitis are justified by serological markers, but they also have distinctive genetic associations (DRB1 and DQB1 genes) and autoantigens. DRB1 alleles are the principal susceptibility factors in white adults, and a six amino acid sequence encoded in the antigen-binding groove of class II molecules of the major histocompatibility complex can influence the selection of autoantigens. Polymorphisms, including variants of SH2B3 and CARD10 genes, may affect immune reactivity and disease severity. The cytochrome mono-oxygenase, CYP2D6, is the autoantigen associated with type 2 autoimmune hepatitis, and it shares homologies with multiple viruses that might promote self-intolerance by molecular mimicry. Chemokines, especially CXCL9 and CXCL10, orchestrate the migration of effector cells to sites of injury and are associated with disease severity. Cells of the innate and adaptive immune responses promote tissue damage, and possible deficiencies in the number and function of regulatory T cells may facilitate the injurious process. Receptor-mediated apoptosis is the principal mechanism of hepatocyte loss, and cell-mediated and antibody-dependent mechanisms of cytotoxicity also contribute. Insights that explain autoimmune hepatitis will allow triggering exogenous antigens to be characterized, risk management to be improved, prognostic indices to be refined, and site-specific therapeutic interventions to emerge.

  12. Osteossíntese diafisiária de tíbia em cães mediante inserção intramedular de pinos de Steinmann pela crista tibial Canine tibial osteosynthesis by the use of intramedullary Steinmann pins through the tibial crest insertion

    Directory of Open Access Journals (Sweden)

    Alexander de Oliveira El-Warrak

    1998-03-01

    Full Text Available As fraturas diafisárias de tíbia possuem alta prevalência na espécie canina. Este estudo visa avaliar o uso de pinos intramedulares de Steinmann na redução destas fraturas. Dez cães de idade, sexo e peso variados, portadores de fratura de tíbia foram submetidos à osteossíntese mediante inserção de dois pinos intramedulares de Steinmann pela crista tibial e em seguida, avaliados clinicamente e radiograficamente durante o período de cicatrização óssea. Diante dos resultados, demonstrou-se a versatilidade e eficiência do método.The diaphiseal tibial fractures have a high prevalence in the canino specie. This study demonstrates the versatility and eficiency in the use of two intramedullary Steinmann pins through normograde and retrograde insertions for reduction of these type of fractures. Ten dogs with variable age sex and weight with fractured tibias were submitted to surgical osteosynthesis procedures and then evaluated clinically and radiografically during the bone healing proccess.

  13. Strange Features of the Earth's Surface Explained: An Interactive Poster

    Science.gov (United States)

    Kellogg, J. B.; Becker, T. W.

    2004-12-01

    The great power of the plate tectonic theory lies in its ability to explain a large numer of diverse observations: the ocean-continental dichotemy, the major features of the sea floor topography, Wadati-Benioff zones, etc. A cursory examination of a physiographic map, however, reveals features that are not trivially explained by plate tectonics, e.g. the different radii of curvature of the island arcs and the bend in the Hawaiian-Emporer chain. This interactive poster aims to establish the current state of knowledge about the Earth's surface and the dynamic processes that control it. The poster itself consists simply of a map of the Earth, accompanied by two sets of Post-It notes. The first set are to be used by viewers to identify problematica for which they would like an explanation. The second set are to be used by others who believe they have explanations, and hopefully key references to support them. The follow-up to this poster will be a "clickable" online map comprising both the observations and their explanations. We hope that this will provide both educators and researchers with an accurate, up-to-date picture of our current state of understanding of the Earth's first-order features.

  14. Mesoscale symmetries explain dynamical equivalence of food webs

    CERN Document Server

    Aufderheide, Helge; Gross, Thilo

    2012-01-01

    A present challenge in complex systems is to identify mesoscale structures that have distinct dynamical implications. In this paper we present a detailed investigation of a previously observed dynamical equivalence of certian ecological food webs. We show that this equivalence is rooted in mesoscale symmetries that exist in these webs. Certain eigenvectors of the Jacobian describing dynamical modes of the system, such as specific instabilities or responses to perturbations, localize on these symmetric motifs. On the one hand this means that by removing a symmetry from the network one obtains a system which has identical dynamics except for the removal of the localized mode. This explains the previously observed equivalence. On the other hand it means that we can identify dynamical modes that only depend on the symmetric motif. Symmetric structures thus provide an example for mesoscale network motifs having distinct and exact implications for the dynamics.

  15. Explaining opinion polarisation with opinion copulas.

    Science.gov (United States)

    Askitas, Nikolaos

    2017-01-01

    An empirically founded and widely established driving force in opinion dynamics is homophily i.e. the tendency of "birds of a feather" to "flock together". The closer our opinions are the more likely it is that we will interact and converge. Models using these assumptions are called bounded confidence models (BCM) as they assume a tolerance threshold after which interaction is unlikely. They are known to produce one or more clusters, depending on the size of the bound, with more than one cluster being possible only in the deterministic case. Introducing noise, as is likely to happen in a stochastic world, causes BCM to produce consensus which leaves us with the open problem of explaining the emergence and sustainance of opinion clusters and polarisation. We investigate the role of heterogeneous priors in opinion formation, introduce the concept of opinion copulas, argue that it is well supported by findings in Social Psychology and use it to show that the stochastic BCM does indeed produce opinion clustering without the need for extra assumptions.

  16. Proposed Pathophysiologic Framework to Explain Some ...

    Science.gov (United States)

    The paper proposes a pathophysiologic framework to explain the well-established epidemiological association between exposure to ambient air particle pollution and premature cardiovascular mortality, and offers insights into public health solutions that extend beyond regularory environmental protections to actions that can be taken by individuals, public health officials, healthcare professionals, city and regional planners, local and state governmental officials and all those who possess the capacity to improve cardiovascular health within the popula­tion.The foundation of the framework rests on the contribution of traditional cardiovascular risk factors acting alone and in concert with long-term exposures to air pollutants to create a conditional susceptibility for clinical vascular events, such as myocardial ischemia and infarction; stroke and lethal ventricular arrhythmias. The conceprual framework focuses on the fact that short-term exposures to ambient air particulate matter (PM) are associated with vascular thrombosis (acute coronary syndrome. stroke, deep venous thrombosis. and pulmonary embolism ) and electrical dysfunction (ventricular arrhythmia); and that individuals having prevalent heart disease are at greatest risk. Moreover, exposure is concomitant with changes in autonomic nervous system balance, systemic in­flammation, and prothrombotic/anti-thrombotic and profibrinolytic-antifibrinolytic balance.Thus, a comprehensive solution to the problem o

  17. 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.

  18. Explaining output volatility: The case of taxation

    DEFF Research Database (Denmark)

    Posch, Olaf

    This paper studies the effects of taxation on output volatility in OECD countries to shed light on the sources of observed heterogeneity over time and across countries. To this end, we derive tax effects on macro aggregates in a stochastic neoclassical model. As a result, taxes are shown to affect...... the second moment of output growth rates without (long-run) effects on the first moment. Taking the model to the data, we exploit observed heterogeneity patterns to estimate effects of tax rates on macro volatility using panel estimation, explicitly modeling the unobserved variance process. We find a strong...

  19. Personality differences explain leadership in barnacle geese

    NARCIS (Netherlands)

    Kurvers, R.H.J.M.; Eijkelenkamp, B.; Van Oers, K.; van Lith, B.; van Wieren, S.E.; Ydenberg, R.C.; Prins, H.H.T.

    2009-01-01

    Personality in animal behaviour describes the observation that behavioural differences between individuals are consistent over time and context. Studies of group-living animals show that movement order among individuals is also consistent over time and context, suggesting that some individuals lead

  20. 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

  1. 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.

  2. Explaining Counterfeit Alcohol Purchases in Russia.

    Science.gov (United States)

    Kotelnikova, Zoya

    2017-04-01

    of surrogate alcohol (i.e., nonbeverage) are more influential in explaining why people purchase counterfeit alcohol. Further research on these 2 factors is needed to more fully understand the purchase and consumption of counterfeit alcoholic beverages. Copyright © 2017 by the Research Society on Alcoholism.

  3. Characteristics explaining performance in downhill mountain biking.

    Science.gov (United States)

    Chidley, Joel B; MacGregor, Alexandra L; Martin, Caoimhe; Arthur, Calum A; Macdonald, Jamie H

    2015-03-01

    To identify physiological, psychological, and skill characteristics that explain performance in downhill (DH) mountain-bike racing. Four studies were used to (1) identify factors potentially contributing to DH performance (using an expert focus group), (2) develop and validate a measure of rider skill (using video analysis and expert judge evaluation), (3) evaluate whether physiological, psychological, and skill variables contribute to performance at a DH competition, and (4) test the specific contribution of aerobic capacity to DH performance. STUDY 1 identified aerobic capacity, handgrip endurance, anaerobic power, rider skill, and self-confidence as potentially important for DH. In study 2 the rider-skill measure displayed good interrater reliability. Study 3 found that rider skill and handgrip endurance were significantly related to DH ride time (β=-0.76 and -0.14, respectively; R2=.73), with exploratory analyses suggesting that DH ride time may also be influenced by self-confidence and aerobic capacity. Study 4 confirmed aerobic capacity as an important variable influencing DH performance (for a DH ride, mean oxygen uptake was 49±5 mL·kg(-1)·min(-1), and 90% of the ride was completed above the 1st ventilatory threshold). In order of importance, rider skill, handgrip endurance, self-confidence, and aerobic capacity were identified as variables influencing DH performance. Practically, this study provides a novel assessment of rider skill that could be used by coaches to monitor training and identify talent. Novel intervention targets to enhance DH performance were also identified, including self-confidence and aerobic capacity.

  4. 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

  5. Nonlinear Dynamic Model Explains The Solar Dynamic

    Science.gov (United States)

    Kuman, Maria

    Nonlinear mathematical model in torus representation describes the solar dynamic. Its graphic presentation shows that without perturbing force the orbits of the planets would be circles; only perturbing force could elongate the circular orbits into ellipses. Since the Hubble telescope found that the planetary orbits of other stars in the Milky Way are also ellipses, powerful perturbing force must be present in our galaxy. Such perturbing force is the Sagittarius Dwarf Galaxy with its heavy Black Hole and leftover stars, which we see orbiting around the center of our galaxy. Since observations of NASA's SDO found that magnetic fields rule the solar activity, we can expect when the planets align and their magnetic moments sum up, the already perturbed stars to reverse their magnetic parity (represented graphically as periodic looping through the hole of the torus). We predict that planets aligned on both sides of the Sun, when their magnetic moments sum-up, would induce more flares in the turbulent equatorial zone, which would bulge. When planets align only on one side of the Sun, the strong magnetic gradient of their asymmetric pull would flip the magnetic poles of the Sun. The Sun would elongate pole-to-pole, emit some energy through the poles, and the solar activity would cease. Similar reshaping and emission was observed in stars called magnetars and experimentally observed in super-liquid fast-spinning Helium nanodroplets. We are certain that NASA's SDO will confirm our predictions.

  6. Explaining stasis: microevolutionary studies in natural populations.

    Science.gov (United States)

    Merilä, J; Sheldon, B C; Kruuk, L E

    2001-01-01

    Microevolution, defined as a change in the genetic constitution of a population over time, is considered to be of commonplace occurrence in nature. Its ubiquity can be inferred from the observation that quantitative genetic divergence among populations usually exceeds that to be expected due to genetic drift alone, and from numerous observations and experiments consistent with local adaptation. Experimental manipulations in natural populations have provided evidence that rapid evolutionary responses may occur in the wild. However, there are remarkably few cases where direct observations of natural populations have revealed microevolutionary changes occurring, despite the frequent demonstration of additive genetic variation and strong directional selection for particular traits. Those few cases where responses congruent with expectation have been demonstrated are restricted to changes over one generation. In this article we focus on possible explanations as to why heritable traits under apparently strong directional selection often fail to show the expected evolutionary response. To date, few of these explanations for apparent stasis have been amenable to empirical testing. We describe new methods, derived from procedures developed by animal breeding scientists, which can be used to address these explanations, and illustrate the approach with examples from long-term studies of collared flycatchers (Ficedula albicollis) and red deer (Cervus elaphus). Understanding why most intensively studied natural populations do not appear to be evolving is an important challenge for evolutionary biology.

  7. Modeling factors explaining physicians’ satisfaction with competence

    Science.gov (United States)

    Lepnurm, Rein; Dobson, Roy Thomas; Peña-Sánchez, Juan-Nicolás; Nesdole, Robert

    2015-01-01

    Recognition explained 60.2% of the variation in Satisfaction with Competence, controlling for years in practice, self-reported health and duties of physicians. Conclusion: Satisfaction with Competence could be affected by excessive accumulation of duties, concerns about quality, efficiency, access, excessive distress, inadequate coping abilities, personal satisfaction with life as a physician, challenges in managing practices and persistent inequities among physicians. PMID:27092256

  8. Modeling factors explaining physicians' satisfaction with competence.

    Science.gov (United States)

    Lepnurm, Rein; Dobson, Roy Thomas; Peña-Sánchez, Juan-Nicolás; Nesdole, Robert

    2015-01-01

    Attention to physician wellness has increased as medical practice gains in complexity. Physician satisfaction with practice is critical for quality of care and practice growth. The purpose of this study was to model physicians' self-reported Satisfaction with Competence as a function of their perceptions of the Quality of Health Services, Distress, Coping, Practice Management, Personal Satisfaction and Professional Equity. Comprehensive questionnaires were sent to a stratified sample of 5300 physicians across Canada. This cross-sectional study focused on physicians who examined and treated individual patients for a final study population of 2639 physicians. Response bias was negligible. The questionnaires contained measures of Satisfaction with Competence, Quality of Health Services, Distress, Coping, Personal Satisfaction, Practice Management and Professional Equity. Exploring relationships was done using Pearson correlations and one-way analysis of variance. Modeling was by hierarchical regressions. The measures were reliable: Satisfaction with Competence (α = .86), Quality (α = .86), Access (α = .82), Distress (α = .82), Coping (α = .76), Personal Satisfaction (α = .78), Practice Management (α = .89) and the dimensions of Professional Equity (Fulfillment, α = .81; Financial, α = .93; and Recognition, α = .75) with comparative validity. Satisfaction with Competence was positively correlated with Quality (r = .32), Efficiency (r = .37) and Access (r = .32); negatively correlated with Distress (r = -.54); and positively correlated with Coping strategies (r = .43), Personal Satisfaction (r = .57), Practice Management (r = .17), Fulfillment (r = .53), Financial (r = .36) and Recognition (r = .54). Physicians' perceptions on Quality, Efficiency, Access, Distress, Coping, Personal Satisfaction, Practice Management, Fulfillment, Pay and Recognition explained 60.2% of the variation

  9. Mackay icosahedron explaining orientation relationship of dispersoids in aluminium alloys.

    Science.gov (United States)

    Muggerud, Astrid Marie F; Li, Yanjun; Holmestad, Randi; Andersen, Sigmund J

    2014-10-01

    The orientation relations (ORs) of the cubic icosahedral quasicrystal approximant phase α-Al(Fe,Mn)Si have been studied after low temperature annealing of a 3xxx wrought aluminium alloy by transmission electron microscopy. From diffraction studies it was verified that the most commonly observed OR for the α-Al(Fe,Mn)Si dispersoids is [1\\bar 11]α // [1\\bar 11]Al, (5\\bar 2\\bar 7)α // (011)Al. This orientation could be explained by assuming that the internal Mackay icosahedron (MI) in the α-phase has a fixed orientation in relation to Al, similar to that of the icosahedral quasi-crystals existing in this alloy system. It is shown that mirroring of the normal-to-high-symmetry icosahedral directions of the MI explains the alternative orientations, which are therefore likely to be caused by twinning of the fixed MI. Only one exception was found, which was related to the Bergman icosahedron internal to the T-phase of the Al-Mg-Zn system.

  10. Conformational flexibility may explain multiple cellular roles of PEST motifs.

    Science.gov (United States)

    Sandhu, Kuljeet Singh; Dash, Debasis

    2006-06-01

    PEST sequences are one of the major motifs that serve as signal for the protein degradation and are also involved in various cellular processes such as phosphorylation and protein-protein interaction. In our earlier study, we found that these motifs contribute largely to eukaryotic protein disorder. This observation led us to evaluate their conformational variability in the nonredundant Protein Data Bank (PDB) structures. For this purpose, crystallographic temperature factors, structural alignment of multiple NMR models, and dihedral angle order parameters have been used in this study. The study has revealed the hypermobility of PEST motifs as compared to other regions of the protein. Conformational flexibility may allow them to participate in number of molecular interactions under different conditions. This analysis may explain the role of protein backbone flexibility in bringing about multiple cellular roles of PEST motifs. 2006 Wiley-Liss, Inc.

  11. 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......, where the tuna maximizes its energy harvest rate. We assume that foraging efficiency increases with body temperature, so that the vertical migrations are thermoregulatory. The tuna's state is characterized by its mean body temperature and depth, and we solve the optimization problem numerically using...... dynamic programming. With little calibration of model parameters, our results are consistent with observed data on vertical movement: we find that small tuna should display constant-depth strategies while large tuna should display vertical migrations. The analysis supports the hypothesis that the tuna...

  12. The media effect in Axelrod's model explained

    Science.gov (United States)

    Peres, L. R.; Fontanari, J. F.

    2011-11-01

    We revisit the problem of introducing an external global field —the mass media— in Axelrod's model of social dynamics, where in addition to their nearest neighbors, the agents can interact with a virtual neighbor whose cultural features are fixed from the outset. The finding that this apparently homogenizing field actually increases the cultural diversity has been considered a puzzle since the phenomenon was first reported more than a decade ago. Here we offer a simple explanation for it, which is based on the pedestrian observation that Axelrod's model exhibits more cultural diversity, i.e., more distinct cultural domains, when the agents are allowed to interact solely with the media field than when they can interact with their neighbors as well. In this perspective, it is the local homogenizing interactions that work towards making the absorbing configurations less fragmented as compared with the extreme situation in which the agents interact with the media only.

  13. Can we explain the observed methane variability after the Mount Pinatubo eruption?

    NARCIS (Netherlands)

    Bândǎ, N.; Krol, M.; Weele, Van M.; Noije, Van T.; Sager, Le 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

  14. Can Sulfur Explain the Bimodal Color Distribution Observed in the Jupiter Trojans?

    Science.gov (United States)

    Blacksberg, Jordana; Mahjoub, Ahmed; Poston, Michael; Brown, Michael E.; Eiler, John; Ehlmann, Bethany; Hodyss, Robert; Hand, Kevin P.; Carlson, Robert W.; Wong, Ian

    2016-10-01

    We present a series of experiments aimed at exploring the hypothesis that the presence or absence of H2S ice on the surface of primitive icy bodies in the early solar system is responsible for the bimodal color distribution of the Jupiter Trojans.Central to our proposed hypothesis is a location-dependent sublimation of ices in the primordial trans-neptunian disk which would have divided objects according to whether they retained H2S on their surfaces for sufficient time to incorporate their constituents into irradiated organic crusts. The irradiated crusts of objects with and without H2S would have different chemistry and therefore different optical properties. Dynamical instability models of the early solar system (e.g. Morbidelli et al., 2005, Nesvorny et al., 2013) predict that Trojans, formed from this primordial population, were later emplaced inward to co-orbit with Jupiter during large-scale rearrangement events. According to our hypothesis, the Trojans today would show evidence of their primordial location with respect to the H2S sublimation line in the form of a bimodal distribution in surface chemistry, and thus color.We present laboratory spectroscopy experiments in support of this hypothesis. Numerous thin ice films composed of H2O, CH3OH, NH3, were produced both with and without H2S. Subsequent processing of these icy bodies was simulated using electron irradiation and heating. Visible reflectance spectra show significant reddening when H2S is present. Mid-infrared spectra confirm the formation of non-volatile sulfur-containing molecules in the products of H2S-containing ices. The infrared spectral properties of the organic residues remaining at room temperature show that sulfur significantly changes the chemistry of these irradiation-produced organics. These experiments suggest that the presence of specific sulfur-bearing chemical species may play an important role in the colors of both the KBOs and Trojans today. This testable hypothesis could feed into the design of experiments that might be performed on potential future missions to the Trojans as well as other primitive bodies.

  15. 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

  16. Does Specialization Explain Marriage Penalties and Premiums?

    Science.gov (United States)

    Killewald, Alexandra; Gough, Margaret

    2013-01-01

    Married men’s wage premium is often attributed to within-household specialization: men can devote more effort to wage-earning when their wives assume responsibility for household labor. We provide a comprehensive evaluation of the specialization hypothesis, arguing that, if specialization causes the male marriage premium, married women should experience wage losses. Furthermore, specialization by married parents should augment the motherhood penalty and the fatherhood premium for married as compared to unmarried parents. Using fixed-effects models and data from the NLSY79, we estimate within-gender differences in wages according to marital status and between-gender differences in the associations between marital status and wages. We then test whether specialization on time use, job traits, and tenure accounts for the observed associations. Results for women do not support the specialization hypothesis. Childless men and women both receive a marriage premium. Marriage augments the fatherhood premium but not the motherhood penalty. Changes in own and spousal employment hours, job traits, and tenure appear to benefit both married men and women, although men benefit more. Marriage changes men’s labor market behavior in ways that augment wages, but these changes do not appear to occur at the expense of women’s wages. PMID:24039271

  17. Does Specialization Explain Marriage Penalties and Premiums?

    Science.gov (United States)

    Killewald, Alexandra; Gough, Margaret

    2013-06-01

    Married men's wage premium is often attributed to within-household specialization: men can devote more effort to wage-earning when their wives assume responsibility for household labor. We provide a comprehensive evaluation of the specialization hypothesis, arguing that, if specialization causes the male marriage premium, married women should experience wage losses. Furthermore, specialization by married parents should augment the motherhood penalty and the fatherhood premium for married as compared to unmarried parents. Using fixed-effects models and data from the NLSY79, we estimate within-gender differences in wages according to marital status and between-gender differences in the associations between marital status and wages. We then test whether specialization on time use, job traits, and tenure accounts for the observed associations. Results for women do not support the specialization hypothesis. Childless men and women both receive a marriage premium. Marriage augments the fatherhood premium but not the motherhood penalty. Changes in own and spousal employment hours, job traits, and tenure appear to benefit both married men and women, although men benefit more. Marriage changes men's labor market behavior in ways that augment wages, but these changes do not appear to occur at the expense of women's wages.

  18. From the Cover: Explaining the moon illusion

    Science.gov (United States)

    Kaufman, Lloyd; Kaufman, James H.

    2000-01-01

    An old explanation of the moon illusion holds that various cues place the horizon moon at an effectively greater distance than the elevated moon. Although both moons have the same angular size, the horizon moon must be perceived as larger. More recent explanations hold that differences in accommodation or other factors cause the elevated moon to appear smaller. As a result of this illusory difference in size, the elevated moon appears to be more distant than the horizon moon. These two explanations, both based on the geometry of stereopsis, lead to two diametrically opposed hypotheses. That is, a depth interval at a long distance is associated with a smaller binocular disparity, whereas an equal depth interval at a smaller distance is associated with a larger disparity. We conducted experiments involving artificial moons and confirmed the hypothesis that the horizon moon is at a greater perceptual distance. Moreover, when a moon of constant angular size was moved closer it was also perceived as growing smaller, which is consistent with the older explanation. Although Emmert's law does not predict the size-distance relationship over long distances, we conclude that the horizon moon is perceived as larger because the perceptual system treats it as though it is much farther away. Finally, we observe that recent explanations substitute perceived size for angular size as a cue to distance. Thus, they imply that perceptions cause perceptions.

  19. JWST NIRCam Time Series Observations

    Science.gov (United States)

    Greene, Tom; Schlawin, E.

    2017-01-01

    We explain how to make time-series observations with the Near-Infrared camera (NIRCam) science instrument of the James Webb Space Telescope. Both photometric and spectroscopic observations are described. We present the basic capabilities and performance of NIRCam and show examples of how to set its observing parameters using the Space Telescope Science Institute's Astronomer's Proposal Tool (APT).

  20. The contribution of psychosocial variables in explaining preschoolers' physical activity.

    Science.gov (United States)

    Gagné, Camille; Harnois, Isabelle

    2013-06-01

    Based on the theory of planned behavior and the structural model of health behavior, the objectives of this study were to verify whether the psychosocial variables of daycare workers (intention, perceived behavioral control, descriptive norm, past behavior) influence preschoolers' physical activity in daycare centers and determine how these psychosocial variables combine with other factors (environmental, sociodemographic, democratic intervention) to explain children's physical activity. Forty-six daycare workers from 20 daycare centers in Quebec, Canada completed a self-reported questionnaire assessing psychosocial and sociodemographic variables. Thirty days later, 242 children wore an accelerometer. A research assistant went to each daycare center to observe the environment and the democratic intervention of daycare workers. The specific direct determinants of children's overall mean count/15 seconds were intention, descriptive norm, democratic intervention, daycare workers' age, availability of material, and children's age and gender. In order to increase the overall mean count/15 seconds among preschoolers, it would be important to motivate daycare workers to make children move. Strategies likely to help motivate daycare workers to take action are also necessary. It might be interesting to encourage them to use democratic intervention with children. Use of material adapted to the needs of the children that stimulates their intellectual and socioaffective development should also be encouraged. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  1. Central venous oxygenation: when physiology explains apparent discrepancies.

    Science.gov (United States)

    Squara, Pierre

    2014-11-10

    Central venous oxygen saturation (ScvO2) >70% or mixed venous oxygen saturation (SvO2) >65% is recommended for both septic and non-septic patients. Although it is the task of experts to suggest clear and simple guidelines, there is a risk of reducing critical care to these simple recommendations. This article reviews the basic physiological and pathological features as well as the metrological issues that provide clear evidence that SvO2 and ScvO2 are adaptative variables with large inter-patient variability. This variability is exemplified in a modeled population of 1,000 standard ICU patients and in a real population of 100 patients including 15,860 measurements. In these populations, it can be seen how optimizing one to three of the four S(c)vO2 components homogenized the patients and yields a clear dependency with the fourth one. This explains the discordant results observed in large studies where cardiac output was increased up to predetermined S(c)vO2 thresholds following arterial oxygen hemoglobin saturation, total body oxygen consumption needs and hemoglobin optimization. Although a systematic S(c)vO2 goal-oriented protocol can be statistically profitable before ICU admission, appropriate intensive care mandates determination of the best compromise between S(c)vO2 and its four components, taking into account the specific constraints of each individual patient.

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

    Science.gov (United States)

    Eduard, Wijnand; Schlünssen, Vivi; Sigsgaard, Torben; Omland, Øyvind; Pearce, Neil; Douwes, Jeroen

    2015-01-01

    Reduced asthma and allergy risks in farmers have been ascribed to microbial exposures. However, selection may also play a role and this was assessed in two Scandinavian farming populations. Asthma prevalence in 739 Danish farming students was compared to that of 1,105 siblings. 8,482 Norwegian farmers were also compared with 349 early retired farmers. The prevalence of ever-asthma was 5.4% in farming students and 5.2% in siblings (OR 1.1; 95%CI 0.73-1.7). Current asthma in farmers was 3.0% compared to 6.3% in farmers who had retired early (OR 1.8, 95%CI 1.1-2.9). Adjustments for early retirement increased the asthma prevalence by 0.3-0.6%. Farmers who had changed production were more likely to have asthma (OR 9.8, 95% CI 6.0-16). 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.

  3. Major Gravitational Phenomena Explained by the Micro-Quanta Paradigm

    Directory of Open Access Journals (Sweden)

    Michelini M.

    2010-01-01

    Full Text Available Some major problems of physics, which remained unsolved within classical and rel- ativistic gravitation theories, are explained adopting the quantum gravity interaction descending from the micro-quanta paradigm. The energy source of the gravitational power P g r , which heats and contracts the Bok’s gas globules harbouring the future stars, is identified and defined as well as the gravitational power generated on the solid / fluid planets. Calculations are carried out to make the comparison between P g r predicted for the solar giant planets and the measured infrared radiation power P int coming from the interior. The case of planets with solid crust (Earth, etc. requires a particular attention due to the threat to stability produced by the thermal dilatation. An analysis is done of the Earth’s planetary equilibrium which may be attained eliminating the temperature rise through the migration of hot internal magma across the crust fractured by earth- quakes. The temperatures observed up to 420,000 years ago in Antartica through Vostok and Epica ice cores suggest the possibility that the Earth gravitational power P g r may be radiated in space through these temperature cycles (Glacial Eras. In this general frame the Earth’s high seismicity and the dynamics of Plate tectonics may find their origin.

  4. Major Gravitational Phenomena Explained by the Micro-Quanta Paradigm

    Directory of Open Access Journals (Sweden)

    Michelini M.

    2010-01-01

    Full Text Available Some major problems of physics, which remained unsolved within classical and relativistic gravitation theories, are explained adopting the quantum gravity interaction descending from the micro-quanta paradigm. The energy source of the gravitational power $P_{gr}$, which heats and contracts the Bok's gas globules harbouring the future stars, is identified and defined as well as the gravitational power generated on the solid/fluid planets. Calculations are carried out to make the comparison between $P_{gr}$ predicted for the solar giant planets and the measured infrared radiation power $P_{int}$ coming from the interior. The case of planets with solid crust (Earth, etc. requires a particular attention due to the threat to stability produced by the thermal dilatation. An analysis is done of the Earth's planetary equilibrium which may be attained eliminating the temperature rise through the migration of hot internal magma across the crust fractured by earthquakes. The temperatures observed up to 420,000 years ago in Antartica through Vostok and Epica ice cores suggest the possibility that the Earth gravitational power $P_{gr}$ may be radiated in space through these temperature cycles (Glacial Eras. In this general frame the Earth's high seismicity and the dynamics of Plate tectonics may find their origin.

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

    Directory of Open Access Journals (Sweden)

    Wijnand Eduard

    2015-09-01

    Full Text Available [i][/i]Introduction and objective. Reduced asthma and allergy risks in farmers have been ascribed to microbial exposures. However, selection may also play a role and this was assessed in two Scandinavian farming populations. Materials and methods. Asthma prevalence in 739 Danish farming students was compared to that of 1,105 siblings. 8,482 Norwegian farmers were also compared with 349 early retired farmers. Results. The prevalence of ever-asthma was 5.4% in farming students and 5.2% in siblings (OR 1.1; 95%CI 0.73–1.7. Current asthma in farmers was 3.0% compared to 6.3% in farmers who had retired early (OR 1.8, 95%CI 1.1–2.9. Adjustments for early retirement increased the asthma prevalence by 0.3–0.6%. Farmers who had changed production were more likely to have asthma (OR 9.8, 95% CI 6.0–16. Conclusions. 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.

  6. Can mathematics explain the evolution of human language?

    Science.gov (United States)

    Witzany, Guenther

    2011-09-01

    Investigation into the sequence structure of the genetic code by means of an informatic approach is a real success story. The features of human language are also the object of investigation within the realm of formal language theories. They focus on the common rules of a universal grammar that lies behind all languages and determine generation of syntactic structures. This universal grammar is a depiction of material reality, i.e., the hidden logical order of things and its relations determined by natural laws. Therefore mathematics is viewed not only as an appropriate tool to investigate human language and genetic code structures through computer science-based formal language theory but is itself a depiction of material reality. This confusion between language as a scientific tool to describe observations/experiences within cognitive constructed models and formal language as a direct depiction of material reality occurs not only in current approaches but was the central focus of the philosophy of science debate in the twentieth century, with rather unexpected results. This article recalls these results and their implications for more recent mathematical approaches that also attempt to explain the evolution of human language.

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

    Science.gov (United States)

    Roudijk, Bram; Donders, Rogier; Stalmeier, Peep

    2017-06-01

    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 dimensions using the World Values Survey (WVS), namely the traditional/rational-secular and the survival/self-expression dimension. We investigate whether there is an association between the WVS cultural dimensions and SRH, both within and between countries. Data from 51 countries in the WVS is used and combined with macroeconomic data from the Worldbank database. The association between SRH and the WVS cultural dimensions is tested within each of the 51 countries and multilevel mixed models are used to test differences between these countries. Socio-demographic and macroeconomic variables are used to correct for non-cultural variables related to SRH. Within countries, the survival/self-expression dimension was positively associated with SRH, while in most countries there was a negative association for the traditional/rational-secular dimension. Values range between 4 and 17% within countries. Further analyses show that the associations within countries and between countries are similar. Controlling for macroeconomic and socio-demographic factors did not change our results. The WVS cultural dimensions predict SRH within and between countries. Contrary to our expectations, traditional/rational-secular values were negatively associated with SRH. As SRH is associated with cultural values between countries, cultural values could be considered when interpreting SRH between countries.

  8. A Conceptual Characterization of Online Videos Explaining Natural Selection

    Science.gov (United States)

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

    2017-11-01

    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 this study, we therefore analyzed the content of 60 videos accessed through the Internet, using a criteria catalog with 38 operationalized variables derived from research literature. The variables were sorted into four categories: (a) key concepts (e.g. limited resources and inherited variation), (b) threshold concepts (abstract concepts with a transforming and integrative function), (c) misconceptions (e.g. that evolution is driven by need), and (d) organismal context (e.g. animal or plant). The results indicate that some concepts are frequently communicated, and certain taxa are commonly used to illustrate concepts, while others are seldom included. In addition, evolutionary phenomena at small temporal and spatial scales, such as subcellular processes, are rarely covered. Rather, the focus is on population-level events over time scales spanning years or longer. This is consistent with an observed lack of explanations regarding how randomly occurring mutations provide the basis for variation (and thus natural selection). The findings imply, among other things, that some components of natural selection warrant far more attention in biology teaching and science education research.

  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. Buzz Factor or Innovation Potential: What Explains Cryptocurrencies' Returns?

    Directory of Open Access Journals (Sweden)

    Sha Wang

    Full Text Available Cryptocurrencies have become increasingly popular since the introduction of bitcoin in 2009. In this paper, we identify factors associated with variations in cryptocurrencies' market values. In the past, researchers argued that the "buzz" surrounding cryptocurrencies in online media explained their price variations. But this observation obfuscates the notion that cryptocurrencies, unlike fiat currencies, are technologies entailing a true innovation potential. By using, for the first time, a unique measure of innovation potential, we find that the latter is in fact the most important factor associated with increases in cryptocurrency returns. By contrast, we find that the buzz surrounding cryptocurrencies is negatively associated with returns after controlling for a variety of factors, such as supply growth and liquidity. Also interesting is our finding that a cryptocurrency's association with fraudulent activity is not negatively associated with weekly returns-a result that further qualifies the media's influence on cryptocurrencies. Finally, we find that an increase in supply is positively associated with weekly returns. Taken together, our findings show that cryptocurrencies do not behave like traditional currencies or commodities-unlike what most prior research has assumed-and depict an industry that is much more mature, and much less speculative, than has been implied by previous accounts.

  11. Buzz Factor or Innovation Potential: What Explains Cryptocurrencies’ Returns?

    Science.gov (United States)

    Wang, Sha

    2017-01-01

    Cryptocurrencies have become increasingly popular since the introduction of bitcoin in 2009. In this paper, we identify factors associated with variations in cryptocurrencies’ market values. In the past, researchers argued that the “buzz” surrounding cryptocurrencies in online media explained their price variations. But this observation obfuscates the notion that cryptocurrencies, unlike fiat currencies, are technologies entailing a true innovation potential. By using, for the first time, a unique measure of innovation potential, we find that the latter is in fact the most important factor associated with increases in cryptocurrency returns. By contrast, we find that the buzz surrounding cryptocurrencies is negatively associated with returns after controlling for a variety of factors, such as supply growth and liquidity. Also interesting is our finding that a cryptocurrency’s association with fraudulent activity is not negatively associated with weekly returns—a result that further qualifies the media’s influence on cryptocurrencies. Finally, we find that an increase in supply is positively associated with weekly returns. Taken together, our findings show that cryptocurrencies do not behave like traditional currencies or commodities—unlike what most prior research has assumed—and depict an industry that is much more mature, and much less speculative, than has been implied by previous accounts. PMID:28085906

  12. Buzz Factor or Innovation Potential: What Explains Cryptocurrencies' Returns?

    Science.gov (United States)

    Wang, Sha; Vergne, Jean-Philippe

    2017-01-01

    Cryptocurrencies have become increasingly popular since the introduction of bitcoin in 2009. In this paper, we identify factors associated with variations in cryptocurrencies' market values. In the past, researchers argued that the "buzz" surrounding cryptocurrencies in online media explained their price variations. But this observation obfuscates the notion that cryptocurrencies, unlike fiat currencies, are technologies entailing a true innovation potential. By using, for the first time, a unique measure of innovation potential, we find that the latter is in fact the most important factor associated with increases in cryptocurrency returns. By contrast, we find that the buzz surrounding cryptocurrencies is negatively associated with returns after controlling for a variety of factors, such as supply growth and liquidity. Also interesting is our finding that a cryptocurrency's association with fraudulent activity is not negatively associated with weekly returns-a result that further qualifies the media's influence on cryptocurrencies. Finally, we find that an increase in supply is positively associated with weekly returns. Taken together, our findings show that cryptocurrencies do not behave like traditional currencies or commodities-unlike what most prior research has assumed-and depict an industry that is much more mature, and much less speculative, than has been implied by previous accounts.

  13. Meteors and how to observe them

    CERN Document Server

    Lunsford, Robert

    2009-01-01

    No two meteor showers are alike, and their variation depends on current conditions and the observer's location. This introduction to the art of meteor observing explains how best to view meteor activity under all conditions and from all locations.

  14. French Polynesia Hotspot Swells Explained By Dynamic Topography

    Science.gov (United States)

    Adam, C.; Yoshida, M.; Isse, T.; Suetsugu, D.; Shiobara, H.; Sugioka, H.; Kanazawa, T.; Fukao, Y.; Barruol, G.

    2007-12-01

    Situated on the South Pacific Superswell, French Polynesia is a region characterized by numerous geophysical anomalies among which a high volcanism concentration. Seven hotspots are required to explain the observed chains, volcanism ages and geochemical trends. Many open questions still remain on the origin of these hotspot chains: are they created by passive uplift of magma due to discontinuities in the structure of the lithosphere or by the ascent of mantle plumes? In this case, at which depth do these plumes initiate in the mantle? Many geophysical observations (bathymetry, gravity, magnetism, volcanism ages..) are used to understand the unique phenomenon occurring on this region. The most useful information may come from tomography models since they provide a 3D view of the mantle. Until recently, the tomography models over the region were quite inaccurate because of the sparse location of the seismic stations. The deployment of two new seismic stations networks (BBOBS and temporary island stations) has lately remedied this failing. The resulting tomography model obtained through the inversion of Rayleigh waves provides the most accurate view of the shallowest part of the mantle (depths ≤ 240 km) beneath French Polynesia. Indeed, for the first time the accuracy of a tomography model is good enough to provide information about plume phenomenology in this complex region. In order to quantify the plumes effect on the seafloor, we compute the dynamic topography through an instantaneous flow model. The general trend of the observed depths anomalies (highs and lows) is well recovered. For example the amplitude, location and extension of the swells associated with the Society, Macdonald and Rarotonga are accurately described by the dynamic model. We also find that dynamic uplift is associated with the Tuamotu archipelago which means that a part of the observed swell is due to the present day action of plumes. Since no volcanism ages are available over this chain

  15. 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...

  16. 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. ...

  17. 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…

  18. Good for the group? Explaining apparent group-level selection

    NARCIS (Netherlands)

    Smallegange, I.M.; Egas, M.

    2015-01-01

    The idea that group selection can explain adaptive trait evolution is still controversial. Recent empirical work proposes evidence for group-level adaptation in a social spider, but the findings can also be explained from an individual-level perspective. The challenge remains to identify situations

  19. Do clones degenerate over time? Explaining the genetic variability of asexuals through population genetic models

    National Research Council Canada - National Science Library

    Janko, Karel; Drozd, Pavel; Eisner, Jan

    2011-01-01

    .... Most recently, Neiman et al. 2009 (Ann N Y Acad Sci.:1168:185-200.) reviewed the distribution of asexual lineage ages estimated from a diverse array of taxa and concluded that neutral processes alone may not explain the observed data...

  20. Explaining the Ordinary Magic of Stable African Multilingualism in the Vaal Triangle Region in South Africa

    Science.gov (United States)

    Coetzee-Van Rooy, Susan

    2014-01-01

    The academic and public debates about language maintenance and language shift in the post-1994 South Africa distract attention from the more productive and important endeavour of explaining the nature of the multilingualism observed among users of African languages in urban contexts. An explanation for this phenomenon is offered here, based on…

  1. Testing Stereotype Threat: Does Anxiety Explain Race and Sex Differences in Achievement?

    Science.gov (United States)

    Osborne, Jason W.

    2001-07-01

    Steele's (1992, 1997) stereotype-threat theory attempts to explain underperformance of minority students in academic domains and of women in mathematics. Steele argues that situational self-relevance of negative group stereotypes in testing situations increases the anxiety these students experience and that these differential anxiety levels explain performance differences. Research shows that manipulation of stereotype threat can affect academic performance. However, there has been little research testing whether anxiety does at least partially explain the relationship between race and achievement. The goal of this study was to examine whether anxiety will explain racial differences in academic performance and gender differences in math performance in the context of a nationally representative sample of high school seniors. Partial mediation was observed, with anxiety explaining significant portions of the racial differences in academic performance. Anxiety also partially explained sex differences in math achievement, although the effect sizes were very small. These results provide general support for Steele's stereotype-threat hypothesis. Copyright 2001 Academic Press.

  2. Comparative study of technique to obtain stem cells from bone marrow collection between the iliac crest and the femoral epiphysis in rabbits Estudo comparativo da técnica para a obtenção de células tronco pela coleta de medula óssea entre a crista ilíaca e epífise do fêmur em coelhos

    Directory of Open Access Journals (Sweden)

    Lilian Piñero Eça

    2009-10-01

    Full Text Available PURPOSE: To assess the technique for the collection of rabbit bone marrow stem cells from different regions to be used as an experimental model in regenerative medicine. METHODS: Thirty rabbits were allocated into 2 groups: GROUP A, n=8, animals that underwent bone marrow blood (BMB harvesting from the iliac crest; and GROUP B: including 22 rabbits that underwent BMB harvesting from the femur epiphysis. After harvesting, mononuclear cells were isolated by density gradient centrifugation (Ficoll - Histopaque. The number of mononuclear cells per ml was counted in a Neubauer chamber and cell viability was checked through Tripan Blue method. RESULTS: Harvesting from the iliac crest yielded an average of 1 ml of BMB and 3,6.10(6 cells/ml over 1 hour of surgery, whereas an average of 3ml of BMB and 11,79.10(6 cells./ml were obtained in 30 min from the femur epiphysis with a reduced animal death rate. CONCLUSION: The analysis for the obtention of a larger number of mononuclear cells/ml from rabbit bone marrow blood was more satisfactory in the femur epiphysis than in the iliac crest.OBJETIVO: Avaliar a técnica mais promissora para a coleta de células tronco adultas de medula óssea de coelhos para a utilização do mesmo como modelo experimental na medicina regenerativa. MÉTODOS: Foram utilizados 30 coelhos divididos em 2 grupos: GRUPO A, n=8, onde realizamos a coleta de sangue de medula óssea (MO da crista ilíaca e grupo B, n=22, onde realizamos a coleta de sangue da medula óssea da epífise do fêmur. Após as coletas, realizamos a separação das células mononucleadas através do gradiente de densidade (Ficoll-Hystopaque. Através da câmara de Neubauer realizamos a contagem das células mononucleadas por ml. Testamos a viabilidade celular através do método Tripan Blue. RESULTADOS: Na coleta de sangue de MO na crista ilíaca obtivemos a média de 1 ml durante 1 hora de procedimento cirúrgico, obtendo a quantidade de 3,6 .10(6 c

  3. 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

  4. To Explain Copernicus: The Islamic Scientific and Religious Contexts

    Science.gov (United States)

    Ragep, F. Jamil

    No one seriously disputes the novelty of Copernicus's monumental decision to put the Earth in motion or its importance for the development of modern science. But that decision can appear quite different when viewed from the perspective of a modern scientist versus that of a contextualist historian. In his recent book To Explain the World, Prof. Weinberg places great store on what he calls aesthetic criteria for understanding Copernicus's choice. The historical record, however, is rather ambiguous on the matter, and if anything supports the view that Copernicus came to his aesthetic justifications (such as the beautiful ordering of the planets) after first reaching his heliocentric theory. So if not aesthetics, what did lead him to go against a two-millenium tradition that placed the Earth firmly in the center of the Cosmos? There are no doubt many factors; one of the most intriguing suggestions, well-argued by Noel Swerdlow, is that Copernicus was led to heliocentrism by his rather conservative desire to restore uniform, circular motion to the heavens and remove the irregularities of Ptolemaic astronomy. Swerdlow has also asserted that this has much to do with Islamic predecessors who were attempting to do the same thing, only within a geocentric framework. In this presentation, I will briefly summarize this Islamic scientific context and then explore the religious beliefs that led not only to the questioning of Ptolemaic scientific authority, including his alleged lack of observational diligence, but also ancient philosophical authority, the latter opening up possibilities for alternative cosmologies, at least one of which included the Earth's motion. Finally, evidence will be presented that connects these Islamic contexts with Copernicus's theories and justifications.

  5. Traits, not origin, explain impacts of plants on larval amphibians.

    Science.gov (United States)

    Cohen, Jillian S; Maerz, John C; Blossey, Bernd

    2012-01-01

    Managing habitats for the benefit of native fauna is a priority for many government and private agencies. Often, these agencies view nonnative plants as a threat to wildlife habitat, and they seek to control or eradicate nonnative plant populations. However, little is known about how nonnative plant invasions impact native fauna, and it is unclear whether managing these plants actually improves habitat quality for resident animals. Here, we compared the impacts of native and nonnative wetland plants on three species of native larval amphibians; we also examined whether plant traits explain the observed impacts. Specifically, we measured plant litter quality (carbon : nitrogen : phosphorus ratios, and percentages of lignin and soluble phenolics) and biomass, along with a suite of environmental conditions known to affect larval amphibians (hydroperiod, temperature, dissolved oxygen, and pH). Hydroperiod and plant traits, notably soluble phenolics, litter C:N ratio, and litter N:P ratio, impacted the likelihood that animals metamorphosed, the number of animals that metamorphosed, and the length of larval period. As hydroperiod decreased, the likelihood that amphibians achieved metamorphosis and the percentage of tadpoles that successfully metamorphosed also decreased. Increases in soluble phenolics, litter N:P ratio, and litter C:N ratio decreased the likelihood that tadpoles achieved metamorphosis, decreased the percentage of tadpoles metamorphosing, decreased metamorph production (total metamorph biomass), and increased the length of larval period. Interestingly, we found no difference in metamorphosis rates and length of larval period between habitats dominated by native and nonnative plants. Our findings have important implications for habitat management. We suggest that to improve habitats for native fauna, managers should focus on assembling a plant community with desirable traits rather than focusing only on plant origin.

  6. Observation Station

    Science.gov (United States)

    Rutherford, Heather

    2011-01-01

    This article describes how a teacher integrates science observations into the writing center. At the observation station, students explore new items with a science theme and use their notes and questions for class writings every day. Students are exposed to a variety of different topics and motivated to write in different styles all while…

  7. Observing nebulae

    CERN Document Server

    Griffiths, Martin

    2016-01-01

    This book enables anyone with suitable instruments to undertake an examination of nebulae and see or photograph them in detail. Nebulae, ethereal clouds of gas and dust, are among the most beautiful objects to view in the night sky. These star-forming regions are a common target for observers and photographers. Griffiths describes many of the brightest and best nebulae and includes some challenges for the more experienced observer. Readers learn the many interesting astrophysical properties of these clouds, which are an important subject of study in astronomy and astrobiology. Non-mathematical in approach, the text is easily accessible to anyone with an interest in the subject. A special feature is the inclusion of an observational guide to 70 objects personally observed or imaged by the author. The guide also includes photographs of each object for ease of identification along with their celestial coordinates, magnitudes and other pertinent information. Observing Nebulae provides a ready resource to allow an...

  8. A framework for explaining reliance on decision aids

    NARCIS (Netherlands)

    Dongen, C.J.G. van; Maanen, P.P. van

    2013-01-01

    This study presents a framework for understanding task and psychological factors affecting reliance on advice from decision aids. The framework describes how informational asymmetries in combination with rational, motivational and heuristic factors explain human reliance behavior. To test hypotheses

  9. Post-modern spirituality: Experience, rather than explain

    African Journals Online (AJOL)

    Test

    2011-06-07

    modern spirituality: Experience, rather than explain. Author: Philip J.W. Schutte1. Affiliation: 1Department of New. Testament Studies,. University of Pretoria,. South Africa. Note: Dr Flip Schutte participates as research associate in the.

  10. A More Accurate Model for Finding Tutorial Segments Explaining APIs

    OpenAIRE

    Jiang, He; Zhang, Jingxuan; Li, Xiaochen; Ren, Zhilei; Lo, David

    2017-01-01

    Developers prefer to utilize third-party libraries when they implement some functionalities and Application Programming Interfaces (APIs) are frequently used by them. Facing an unfamiliar API, developers tend to consult tutorials as learning resources. Unfortunately, the segments explaining a specific API scatter across tutorials. Hence, it remains a challenging issue to find the relevant segments. In this study, we propose a more accurate model to find the exact tutorial fragments explaining...

  11. Light and electron microscopic observations of the reproductive swarmer cells of nassellarian and spumellarian polycystines (Radiolaria).

    Science.gov (United States)

    Yuasa, Tomoko; Takahashi, Osamu

    2016-06-01

    We observed reproductive swarmer cells of the nassellarian and spumellarian polycystine radiolarians Didymocyrtis ceratospyris, Pterocanium praetextum, Tetrapyle sp., and Triastrum aurivillii using light, scanning and transmission electron microscopy. The swarmer cells had subspherical to ovoid or spindle shapes with two unequal flagella tapered to whip-like ends. The cell size was approximately 2.5-5.5μm long and 1.6-2.2μm wide, which is significantly smaller than that of the collodarian (colonial or naked) polycystine radiolarians. Transmission electron microscopy revealed that the swarmer cells possessed a nucleus, mitochondria with tubular cristae, Golgi body, and small lipid droplets in the cytoplasm; they also had a large vacuole in which a single crystalline inclusion (approx. 1.0-1.5μm) that was probably celestite (SrSO4) was enclosed. The swarmer cells were released directly from the parent cells. At that time, morphological change such as encystment was not observed in the parent cells, and the axopodia remained extended in a period of swarmer reproduction for floating existence. This may have prevented the polycystine swarmers from rapidly sinking down to great depths. Thus, we concluded that the polycystine radiolarians release the swarmer cells into the photic layer in the same way as the symbiotic acantharians. Copyright © 2016 Elsevier GmbH. All rights reserved.

  12. Observational astrophysics

    CERN Document Server

    Léna, Pierre; Lebrun, François; Mignard, François; Pelat, Didier

    2012-01-01

    This is the updated, widely revised, restructured and expanded third edition of Léna et al.'s successful work Observational Astrophysics. It presents a synthesis on tools and methods of observational astrophysics of the early 21st century. Written specifically for astrophysicists and graduate students, this textbook focuses on fundamental and sometimes practical limitations on the ultimate performance that an astronomical system may reach, rather than presenting particular systems in detail. In little more than a decade there has been extraordinary progress in imaging and detection technologies, in the fields of adaptive optics, optical interferometry, in the sub-millimetre waveband, observation of neutrinos, discovery of exoplanets, to name but a few examples. The work deals with ground-based and space-based astronomy and their respective fields. And it also presents the ambitious concepts behind space missions aimed for the next decades. Avoiding particulars, it covers the whole of the electromagnetic spec...

  13. Observable supertranslations

    Science.gov (United States)

    Bousso, Raphael; Porrati, Massimo

    2017-10-01

    We show that large gauge transformations in asymptotically flat spacetime can be implemented by sandwiching a shell containing the ingoing hard particles between two finite-width shells of soft gauge excitations. Integration of the graviton Dirac bracket implies that our observable soft degrees of freedom obey the algebra imposed by Strominger et al. on unobservable boundary degrees of freedom. Thus, we provide both a derivation and an observable realization of this algebra. We recently showed that soft charges fail to constrain the hard scattering problem, and so cannot be relevant to the black hole information paradox. By expressing the Bondi-van der Burg-Metzner-Sachs (BMS) algebra in terms of observable quantities, the present work shows that this conclusion was not an artifact of working with strictly zero frequency soft modes. The conservation laws associated with asymptotic symmetries are seen to arise physically from free propagation of infrared modes.

  14. 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......, ECtHR and IACHR. It is found that the threat of governmental noncompliance and the strength of the constituency possessed by an IC have the most explanatory power, although there is still a significant residual that can only be explained by looking at factors relating to judicial choices and agency....

  15. 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 (disparities. Results. The model explained 45% to 94% of LBW and 64% to 94% of PTB disparities between the African ancestry groups and European ancestry. Differences in prenatal care use and geographic location were the most important contributors, followed by socioeconomic differences. The model explained the majority of the disparities for mixed African ancestry and part of the disparity for African ancestry alone. Conclusions. 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

  16. Deltagende observation

    DEFF Research Database (Denmark)

    Warming, H.

    2007-01-01

    Artiklen er en introduktion til deltagende observation som samfundsvidenskabelig metode. I artiklen introduceres til de teorihistoriske rødder, forskellige tilgange til metoden, den konkrete fremgangsmåde og de dermed forbundne overvejelser. Endvidere eksemplificeres metoden, og der opstilles en...

  17. Lookback Time: Observing Cosmic History.

    Science.gov (United States)

    Corwin, Mike; Wachowiak, Dale

    1989-01-01

    The difference in time between the emission and reception of light is called the "lookback" time. This article explores implications of lookback time and explains some of the puzzling questions posed by the scientific observation of cosmic history. Provides several pictures and diagrams. (YP)

  18. Flare Observations

    Directory of Open Access Journals (Sweden)

    Benz Arnold O.

    2008-02-01

    Full Text Available Solar flares are observed at all wavelengths from decameter radio waves to gamma-rays at 100 MeV. This review focuses on recent observations in EUV, soft and hard X-rays, white light, and radio waves. Space missions such as RHESSI, Yohkoh, TRACE, and SOHO have enlarged widely the observational base. They have revealed a number of surprises: Coronal sources appear before the hard X-ray emission in chromospheric footpoints, major flare acceleration sites appear to be independent of coronal mass ejections (CMEs, electrons, and ions may be accelerated at different sites, there are at least 3 different magnetic topologies, and basic characteristics vary from small to large flares. Recent progress also includes improved insights into the flare energy partition, on the location(s of energy release, tests of energy release scenarios and particle acceleration. The interplay of observations with theory is important to deduce the geometry and to disentangle the various processes involved. There is increasing evidence supporting reconnection of magnetic field lines as the basic cause. While this process has become generally accepted as the trigger, it is still controversial how it converts a considerable fraction of the energy into non-thermal particles. Flare-like processes may be responsible for large-scale restructuring of the magnetic field in the corona as well as for its heating. Large flares influence interplanetary space and substantially affect the Earth’s lower ionosphere. While flare scenarios have slowly converged over the past decades, every new observation still reveals major unexpected results, demonstrating that solar flares, after 150 years since their discovery, remain a complex problem of astrophysics including major unsolved questions.

  19. Flare Observations

    Directory of Open Access Journals (Sweden)

    Arnold O. Benz

    2016-12-01

    Full Text Available Abstract Solar flares are observed at all wavelengths from decameter radio waves to gamma-rays beyond 1 GeV. This review focuses on recent observations in EUV, soft and hard X-rays, white light, and radio waves. Space missions such as RHESSI, Yohkoh, TRACE, SOHO, and more recently Hinode and SDO have enlarged widely the observational base. They have revealed a number of surprises: Coronal sources appear before the hard X-ray emission in chromospheric footpoints, major flare acceleration sites appear to be independent of coronal mass ejections, electrons, and ions may be accelerated at different sites, there are at least 3 different magnetic topologies, and basic characteristics vary from small to large flares. Recent progress also includes improved insights into the flare energy partition, on the location(s of energy release, tests of energy release scenarios and particle acceleration. The interplay of observations with theory is important to deduce the geometry and to disentangle the various processes involved. There is increasing evidence supporting magnetic reconnection as the basic cause. While this process has become generally accepted as the trigger, it is still controversial how it converts a considerable fraction of the energy into non-thermal particles. Flare-like processes may be responsible for large-scale restructuring of the magnetic field in the corona as well as for its heating. Large flares influence interplanetary space and substantially affect the Earth’s ionosphere. Flare scenarios have slowly converged over the past decades, but every new observation still reveals major unexpected results, demonstrating that solar flares, after 150 years since their discovery, remain a complex problem of astrophysics including major unsolved questions.

  20. Flare Observations

    Science.gov (United States)

    Benz, Arnold O.

    2017-12-01

    Solar flares are observed at all wavelengths from decameter radio waves to gamma-rays beyond 1 GeV. This review focuses on recent observations in EUV, soft and hard X-rays, white light, and radio waves. Space missions such as RHESSI, Yohkoh, TRACE, SOHO, and more recently Hinode and SDO have enlarged widely the observational base. They have revealed a number of surprises: Coronal sources appear before the hard X-ray emission in chromospheric footpoints, major flare acceleration sites appear to be independent of coronal mass ejections, electrons, and ions may be accelerated at different sites, there are at least 3 different magnetic topologies, and basic characteristics vary from small to large flares. Recent progress also includes improved insights into the flare energy partition, on the location(s) of energy release, tests of energy release scenarios and particle acceleration. The interplay of observations with theory is important to deduce the geometry and to disentangle the various processes involved. There is increasing evidence supporting magnetic reconnection as the basic cause. While this process has become generally accepted as the trigger, it is still controversial how it converts a considerable fraction of the energy into non-thermal particles. Flare-like processes may be responsible for large-scale restructuring of the magnetic field in the corona as well as for its heating. Large flares influence interplanetary space and substantially affect the Earth's ionosphere. Flare scenarios have slowly converged over the past decades, but every new observation still reveals major unexpected results, demonstrating that solar flares, after 150 years since their discovery, remain a complex problem of astrophysics including major unsolved questions.

  1. The Controlled Natural Language of Randall Munroe's Thing Explainer

    OpenAIRE

    Kuhn, Tobias

    2016-01-01

    It is rare that texts or entire books written in a Controlled Natural Language (CNL) become very popular, but exactly this has happened with a book that has been published last year. Randall Munroe's Thing Explainer uses only the 1'000 most often used words of the English language together with drawn pictures to explain complicated things such as nuclear reactors, jet engines, the solar system, and dishwashers. This restricted language is a very interesting new case for the CNL community. I d...

  2. BOOK REVIEW: Observational Cosmology Observational Cosmology

    Science.gov (United States)

    Howell, Dale Andrew

    2013-04-01

    Observational Cosmology by Stephen Serjeant fills a niche that was underserved in the textbook market: an up-to-date, thorough cosmology textbook focused on observations, aimed at advanced undergraduates. Not everything about the book is perfect - some subjects get short shrift, in some cases jargon dominates, and there are too few exercises. Still, on the whole, the book is a welcome addition. For decades, the classic textbooks of cosmology have focused on theory. But for every Sunyaev-Zel'dovich effect there is a Butcher-Oemler effect; there are as many cosmological phenomena established by observations, and only explained later by theory, as there were predicted by theory and confirmed by observations. In fact, in the last decade, there has been an explosion of new cosmological findings driven by observations. Some are so new that you won't find them mentioned in books just a few years old. So it is not just refreshing to see a book that reflects the new realities of cosmology, it is vital, if students are to truly stay up on a field that has widened in scope considerably. Observational Cosmology is filled with full-color images, and graphs from the latest experiments. How exciting it is that we live in an era where satellites and large experiments have gathered so much data to reveal astounding details about the origin of the universe and its evolution. To have all the latest data gathered together and explained in one book will be a revelation to students. In fact, at times it was to me. I've picked up modern cosmological knowledge through a patchwork of reading papers, going to colloquia, and serving on grant and telescope allocation panels. To go back and see them explained from square one, and summarized succinctly, filled in quite a few gaps in my own knowledge and corrected a few misconceptions I'd acquired along the way. To make room for all these graphs and observational details, a few things had to be left out. For one, there are few derivations

  3. Explaining the Unexplained: Residual Wage Inequality, Manufacturing Decline, and Low-Skilled Immigration

    OpenAIRE

    Gould, Eric D.

    2015-01-01

    This paper investigates whether the increasing "residual wage inequality" trend is related to manufacturing decline and the influx of low-skilled immigrants. There is a vast literature arguing that technological change, international trade, and institutional factors have played a significant role in the inequality trend. However, most of the trend is unexplained by observable factors. This paper attempts to "explain" the growth in the unexplained variance of wages by exploiting variation acro...

  4. Explaining Recent Trends in the U.S. Teen Birth Rate

    OpenAIRE

    Melissa Schettini Kearney; Levine, Phillip B.

    2012-01-01

    We investigate trends in the U.S. rate of teen childbearing between 1981 and 2010, giving particular attention to the sizable decline that has occurred since 1991. Our primary focus is on establishing the role of state-level demographic changes, economic conditions, and targeted policies in driving recent aggregate trends. We offer three main observations. First, the recent decline cannot be explained by the changing racial and ethnic composition of teens; in fact, all else equal, a rising sh...

  5. The hexagonal lattice marks in the muroids rodent explain molar-cusp enamel line

    OpenAIRE

    Ruiz Bustos, A.

    2011-01-01

    The crown enamel line of muroids rodent has geometric traces that coincide exactly with an equilateral triangular lattice. This finding helps to explain the muroids dental pattern from a novel perspective in molar morphology that it is based on hexagonal structures. The adult traces imply that the morphology of the teeth mammals is consequence of a morphogenetic process. This is the study of the hexagonal lattice marks observed in the enamel line, and therefore called odontohexasymmetry. ...

  6. Explaining ESL Essay Holistic Scores: A Multilevel Modeling Approach

    Science.gov (United States)

    Barkaoui, Khaled

    2010-01-01

    This study adopted a multilevel modeling (MLM) approach to examine the contribution of rater and essay factors to variability in ESL essay holistic scores. Previous research aiming to explain variability in essay holistic scores has focused on either rater or essay factors. The few studies that have examined the contribution of more than one…

  7. 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

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

    African Journals Online (AJOL)

    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. Two different recruitment and spawner number datasets were available: a VPA-developed dataset, for the period 1952–1987, and ...

  9. Exploring the Fullerenes. How Geometrical Ideas Explain Strange ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 5; Issue 8. Exploring the Fullerenes - How Geometrical Ideas Explain Strange Fullerene Structures. K N Joshipura. Classroom Volume 5 Issue 8 August 2000 pp 92-98. Fulltext. Click here to view fulltext PDF. Permanent link:

  10. 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.

  11. 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…

  12. 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.…

  13. 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

  14. Explaining Variation in Teachers' Perceptions of Principals' Leadership: A Replication.

    Science.gov (United States)

    Leithwood, Kenneth; Jantzi, Doris

    1997-01-01

    Explores factors influencing teachers to attribute transformational leadership qualities to some principals and not others, based on a survey of 1,253 teachers from a large school system in Ontario, Canada. Results corroborated a previous study's findings that teachers' leadership attributions were largely explained by alterable variables (like…

  15. Victims or perpetrators? Explaining media framing of Roma across Europe

    NARCIS (Netherlands)

    Kroon, A.C.; Kluknavská, A.; Vliegenthart, R.; Boomgaarden, H.G.

    2016-01-01

    Discrimination against Roma is a reality across Europe. The extent to which stereotyped, discriminatory beliefs of this minority group are reflected or reinforced by news media has received only limited attention. This study investigates media framing of Roma and explains variation in how European

  16. Can Input Explain Children's Me-for-I Errors?

    Science.gov (United States)

    Kirjavainen, Minna; Theakston, Anna; Lieven, Elena

    2009-01-01

    English-speaking children make pronoun case errors producing utterances where accusative pronouns are used in nominative contexts ("me do it"). We investigate whether complex utterances in the input ("Let me do it") might explain the origin of these errors. Longitudinal naturalistic data from seventeen English-speaking two- to four-year-olds was…

  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. Explaining the forest product selling behavior of private woodland owners

    Science.gov (United States)

    David N. Larsen; David A. Gansner; David A. Gansner

    1973-01-01

    A multiple-variable screening technique, AID, was used to explain the forest-product-sales behavior of private woodland owners. Results provide a basis for policy-related inferences and suggest an optimal strategy for encouraging sales of forest products.

  19. Design of an explainable machine learning challenge for video interviews

    NARCIS (Netherlands)

    Escalante, H.J.; Guyon, I.; Escalera, S.; Jacques, J.; Madadi, M.; Baró , X.; Ayache, S.; Viegas, E.; Gü ç lü tü rk, Y.; Gü ç lü , U.; Gerven, M.A.J. van; Lier, R.J. van

    2017-01-01

    This paper reviews and discusses research advances on "explainable machine learning" in computer vision. We focus on a particular area of the "Looking at People" (LAP) thematic domain: first impressions and personality analysis. Our aim is to make the computational intelligence and computer vision

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

    NARCIS (Netherlands)

    Reijnders, Laurie

    2017-01-01

    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

  1. 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

  2. Visualisation and Reasoning in Explaining the Phases of the Moon

    Science.gov (United States)

    Subramaniam, K.; Padalkar, Shamin

    2009-01-01

    In this study, we examine how subjects set up, transform, and reason with models that they establish on the basis of known facts as they seek to explain a familiar everyday phenomenon--the phases of the moon. An interview schedule was designed to elicit subjects' reasoning, and in the case where explanations were mistaken, to induce a change in…

  3. 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,…

  4. What it Needs to Make Plant Function Explainable

    Science.gov (United States)

    Joswig, J. S.; Reu, B.; Wirth, C.; Richter, R.; Kattge, J.; Mahecha, M. D.

    2016-12-01

    Broad biogeographic patterns of plant trait identity and diversity across large spatial scales are strongly related to and shaped by environmental drivers. Hence, estimations of plant function from environmental drivers bear many promises for a better understanding of biospheric responses to global change. We assess requirements in terms of information needed to make plant traits predictable. Therefore we link plant trait data (TRY, www.try-db.org) to atmosphere (EarthSystemDataCube, earthsystemdatacube.net) and soil data (ISRIC, www.isric.org), then the environmental factors are selected for each trait (partial least square regression). We analyze i) the numbers of predictors, ii) the type of relationship and iii) the relative importance of atmospheric and soil factors. Our study shows that the environmental filter acts on trait identity and diversity in various ways. Trait identity is mostly better explicable than trait diversity. Trait identities, which are well explained relative to their number of predictors were most seed traits, leaf traits, except for nutrient related traits and plant height. For the trait diversities the best explained ones were most seed traits, LDMC and plant height. The environmental drivers are most relevant when included as non-linear and envelope variables for both trait identity and diversity. Overall, atmospheric factors explained trait identity and diversity better than soil-related predictors. Leaf and seed traits, are least explained by soil-related predictors. Stem traits, however, in comparison are explained by the greatest share of soil predictors. The present study aims to refine the picture of environmental filtering for plant traits, while it points to chances and missing information when it comes to predicting functional identity and diversity with an unprecedentedly large and multi-perspective set of information.

  5. 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.

  6. Les observables

    Directory of Open Access Journals (Sweden)

    Bergounioux Gabriel

    2014-07-01

    jacents ? Au cours de cette table ronde, la question des observables sera interrogée en partant d’une réflexion concernant les études qui se fondent sur l’inventaire empirique des données pour construire leurs analyses (statistique lexicale, Labphon, corpus-guided linguistics, sociolinguistique variationniste, linguistique cognitive… et en allant jusqu’aux théories qui postulent l’existence de formalismes préalables dont les discours et les textes ratifieraient, par l’actualisation et la distribution de leurs occurrences, la pertinence épistémologique.

  7. Mars Observer Orbit Insertion Briefing

    Science.gov (United States)

    1993-01-01

    Steve Wall is the host of this video entitled, "Return to the Red Planet". Live animation of the Mars Observer orbiting Mars is presented. Steve Wall explains the spacecraft insertion maneuver and also explains the purpose for the Mars Observer launch. Live coverage of the Cape Canaveral launch of the Mars Observer is also presented. Suzanne Dodd, Chief of the Mission Planning team describes the burn start and how the spacecraft will be captured by Mars' gravity. Glenn Cunningham, Mars Observer Project Manager, gives background information on the Mars Observer and describes the organizations behind the Mars Observer Spacecraft, such as the Deep Space Network, the Mission Operation Support Office, Science Investigators, the Flight Engineering Office, Operations Office, and the Ground Data System Office. Dr. William Piotrowski, Acting Director, Solar System Exploration Division, NASA, talks about the purpose of the Mars Pathfinder which is to develop the technology and systems for landing small science packages on Mars. Mr. Roger Gibbs, Former Mars Observer Spacecraft Systems Engineer, tells us how the Mars Observer was built and describes the structural elements on the Mars Observer. The 11-month cruise period for the spacecraft is given by Joseph Beerer, Manager of the Engineering office. The thrust for the Mars Orbit Insertion is described by Ronald Klemetson, Technical Manager, Propulsion Subsystem Jet Propulsion Laboratory (JPL). George Chen, Lead Engineer Attitude and Articulation Subsystem Spacecraft Team, explains the importance of the attitude control engines on the Spacecraft. Marvin Traxler, Manager of Tracking and Data Acquisition, describes how searching for a signal from the Mars Observer works. See NONP-NASA-VT-2000081555 for a continuation of this discussion with Marvin Traxler.

  8. The Intrinsic Temperature Sensitivity of Ecosystem Respiration as Explained by Thermodynamics

    Science.gov (United States)

    Woods, K. D.; Arcus, V. L.; Schipper, L. A.; Schwalm, C.

    2016-12-01

    Biological processes exhibit thermal optima; a range within which processes such as photosynthesis and respiration reach a maximum rate. The response of these processes to temperature is well observed in the field and lab experiments, but is poorly captured or explained by widely used Arrhenius equations and Q10 constants. Both Arrhenius and Q10-based explanations of respiration misleadingly project an exponential increase in rate with temperature and rely on concepts such as enzyme denaturation to explain decreases at higher temperatures. This explanation is problematic in that it ignores observed declines which are far below experimental observations of enzyme denaturation. Here, we present a novel theory which explains the intrinsic temperature dependence of plant, soil, and ecosystem respiration based on the thermodynamics of enzyme-catalysed reactions. MacroMolecular Rate Theory (MMRT) allows for the calculation of thermal optima for respiration and photosynthesis (an important input substrate for respiration), as well as for the calculation of the curvature of response which defines temperatures where changes in rates are maximal. To test this theory, we used the recently released FLUXNET2015 dataset which is comprised of 165 sites and 23 years of data. We accounted for the effect of water through partial correlation analysis and extracted the temperature signal of respiration and photosynthesis to fit MacroMolecular Rate Theory. Across ecosystems and biomes, photosynthesis and respiration rates maximized at 7-18oC and 15-27oC respectively. At 16-25oC, and 26-36oC rates photosynthesis and respiration declined. These points, and this method for explaining changes in these processes are important for understanding and predicting net ecosystem carbon gain or loss. They demonstrate temperatures where the sign and magnitude of carbon exchange undergoes important shifts, holding important implications for future carbon cycling.

  9. 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

  10. 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.

  11. 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.

  12. Microbes can help explain the evolution of host altruism

    Science.gov (United States)

    Lewin-Epstein, Ohad; Aharonov, Ranit; Hadany, Lilach

    2017-01-01

    The evolution of altruistic behaviour, which is costly to the donor but beneficial for the recipient, is among the most intriguing questions in evolutionary biology. Several theories have been proposed to explain it, including kin selection, group selection and reciprocity. Here we propose that microbes that manipulate their hosts to act altruistically could be favoured by selection, and may play a role in the widespread occurrence of altruism. Using computational models, we find that microbe-induced altruism can explain the evolution of host altruistic behaviour under wider conditions than host-centred theories, including in a fully mixed host population, without repeating interactions or individual recognition. Our results suggest that factors such as antibiotics that kill microbes might negatively affect cooperation in a wide range of organisms. PMID:28079112

  13. 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.

  14. 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.

  15. 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.

  16. Do Prices and Attributes Explain International Differences in Food Purchases?

    OpenAIRE

    Dubois, Pierre; Griffith, Rachel; Nevo, Aviv

    2014-01-01

    Food purchases differ substantially across countries. We use detailed household level data from the US, France and the UK to (i) document these differences; (ii) esti- mate a demand system for food and nutrients, and (iii) simulate counterfactual choices if households faced prices and nutritional characteristics from other countries. We find that differences in prices and characteristics are important and can explain some difference (e.g., US-France difference in caloric intake), but generall...

  17. Explaining entrepreneurial orientation among university students: evidence from Italy

    OpenAIRE

    A. Arrighetti; Landini, F.; L. Caricati; Monacelli, N.

    2013-01-01

    This paper presents one of the first studies on the entrepreneurial orientation of Italian university students. For a large sample of students from the University of Parma (Italy), we estimate the sources of entrepreneurial intent, distinguishing between the propensity to start a new business and the perceived likelihood of becoming an entrepreneur. In line with previous research in other countries, entrepreneurial intent is explained by a wide set of variables, including psychological, socia...

  18. High Enough? Explaining and Predicting Traveler Satisfaction Using Airline Review

    OpenAIRE

    Lacic, Emanuel; Kowald, Dominik; Lex, Elisabeth

    2016-01-01

    Air travel is one of the most frequently used means of transportation in our every-day life. Thus, it is not surprising that an increasing number of travelers share their experiences with airlines and airports in form of online reviews on the Web. In this work, we thrive to explain and uncover the features of airline reviews that contribute most to traveler satisfaction. To that end, we examine reviews crawled from the Skytrax air travel review portal. Skytrax provides four review categories ...

  19. Does politics matter? Explaining swings in wind power installations

    Directory of Open Access Journals (Sweden)

    Espen Moe

    2017-04-01

    Full Text Available This is a social science article on the politics of wind power, and on whether or not politics actually matters. While it may seem obvious that politics actually does, I argue that the arguments that we encounter about wind power very often are about economics, technology or geography, arguments that have something deterministic to them, and which leaves politics a lesser factor. Against this, I argue that while these arguments may go a long way toward explaining the general upward trajectory of wind power, they do a bad job of explaining swings in wind power installations, why some countries are more successful at wind power in general, and why within countries, you typically have periods of both stops and starts. For this, we need a political explanation. Of these, there are many, but from the vantage point of political economy, I suggest a focus on vested interests, among other reasons because this is an explanation that can be used to analyze both democracies and non-democracies, and both presidential and parliamentarian systems. Methodologically, the study is a qualitative comparative case-study of five countries (US, Denmark, Japan, Germany, China employing a combination of John Stuart Mill’s comparative methods and process-tracing. The main finding is that if you want to explain swings in wind power installations, you need to focus on the political system, and in particular on the interest politics that goes on behind the scenes. While economic, technological, or geographic explanations all provide useful amounts of understanding, neither explanation can explain swings. There is only one explanation that remains constant and important in every one of the five cases. Economics, technology and geography play different roles in different contexts to different extents. Politics on the other hand always plays a role.

  20. Military Legislation: Explaining Military Officers’ Writing Deficiencies

    Science.gov (United States)

    2016-06-01

    Class ,” in Cross-Talk in Comp Theory: A Reader, ed. Victor Villanueva, 2nd ed. (Urbana, IL: National Council of Teachers of English , 2003), 723... important ideas, for example, unusual cases and procedural detail, later,” and putting “ material of direct interest to the ordinary user of the...2. Material that explains and amplifies the lead 3. Necessary background material 4. Secondary or less important material 5. Descending pyramids

  1. 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.

  2. Explaining the Objective-Subjective Memory Discrepancy in Epilepsy

    OpenAIRE

    Russell, Helen

    2013-01-01

    Previous research has shown that epilepsy patients frequently report increased memory impairments compared to the normal population but that their performance on standardised memory tests does not reflect this, displaying an “objective-subjective memory discrepancy” not seen in healthy controls (e.g. Witt et al., 2012). Multiple factors have been proposed to explain this phenomenon, many summarised comprehensively by Hall et al. (2009). These explanations include methodological flaws in both ...

  3. 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...

  4. Explaining Success and Failure: Counterinsurgency in Malaya and India

    Science.gov (United States)

    2010-12-01

    will use the comparative case study method to analyze and explain success in counterinsurgency, and specifically, why overall at the national level...the accused are punished harshly and at times, executed to illustrate quick justice. The Maoist courts also known as Kangaroo courts are...atimes/South_Asia/LE20Df02.html (accessed October 27, 2010). 96 Sarma Venkateswara Vemuri, “Is Democracy a Farce in India – Part 1: Kangaroo Courts Roost

  5. Does sexual selection explain human sex differences in aggression?

    Science.gov (United States)

    Archer, John

    2009-08-01

    I argue that the magnitude and nature of sex differences in aggression, their development, causation, and variability, can be better explained by sexual selection than by the alternative biosocial version of social role theory. Thus, sex differences in physical aggression increase with the degree of risk, occur early in life, peak in young adulthood, and are likely to be mediated by greater male impulsiveness, and greater female fear of physical danger. Male variability in physical aggression is consistent with an alternative life history perspective, and context-dependent variability with responses to reproductive competition, although some variability follows the internal and external influences of social roles. Other sex differences, in variance in reproductive output, threat displays, size and strength, maturation rates, and mortality and conception rates, all indicate that male aggression is part of a sexually selected adaptive complex. Physical aggression between partners can be explained using different evolutionary principles, arising from the conflicts of interest between males and females entering a reproductive alliance, combined with variability following differences in societal gender roles. In this case, social roles are particularly important since they enable both the relatively equality in physical aggression between partners from Western nations, and the considerable cross-national variability, to be explained.

  6. Conceptual Foundations of Systems Biology Explaining Complex Cardiac Diseases.

    Science.gov (United States)

    Louridas, George E; Lourida, Katerina G

    2017-02-21

    Systems biology is an important concept that connects molecular biology and genomics with computing science, mathematics and engineering. An endeavor is made in this paper to associate basic conceptual ideas of systems biology with clinical medicine. Complex cardiac diseases are clinical phenotypes generated by integration of genetic, molecular and environmental factors. Basic concepts of systems biology like network construction, modular thinking, biological constraints (downward biological direction) and emergence (upward biological direction) could be applied to clinical medicine. Especially, in the field of cardiology, these concepts can be used to explain complex clinical cardiac phenotypes like chronic heart failure and coronary artery disease. Cardiac diseases are biological complex entities which like other biological phenomena can be explained by a systems biology approach. The above powerful biological tools of systems biology can explain robustness growth and stability during disease process from modulation to phenotype. The purpose of the present review paper is to implement systems biology strategy and incorporate some conceptual issues raised by this approach into the clinical field of complex cardiac diseases. Cardiac disease process and progression can be addressed by the holistic realistic approach of systems biology in order to define in better terms earlier diagnosis and more effective therapy.

  7. Face Context Advantage Explained by Vernier and Separation Discrimination Acuity

    Directory of Open Access Journals (Sweden)

    Hugh R Wilson

    2013-01-01

    Full Text Available Seeing facial features in the context of a full face is known to provide an advantage for perception. Using an interocular separation perception task we confirmed that seeing eyes within the context of a face improves discrimination in synthetic faces. We also show that this improvement of the face-context can be explained using the presence of individual components of the face such as the nose mouth, or head-outline. We demonstrate that improvements due to the presence of the nose, and head-outline can be explained in terms of two-point separation measurements, obeying Weber's law as established in the literature. We also demonstrate that performance improvements due to the presence of the mouth can be explained in terms of vernier acuity judgements between eye positions and the corners of the mouth. Overall, our study shows that the improvements in perception of facial features due to the face-context effect can be traced to well understood basic visual measurements that may play a very general role in perceptual measurements of distance. Deficiencies in these measurements may also play a role in prosopagnosia. Additionaly, we show interference of the eyebrows with the face-inversion effect for interocular discrimination.

  8. Conceptual Foundations of Systems Biology Explaining Complex Cardiac Diseases

    Directory of Open Access Journals (Sweden)

    George E. Louridas

    2017-02-01

    Full Text Available Systems biology is an important concept that connects molecular biology and genomics with computing science, mathematics and engineering. An endeavor is made in this paper to associate basic conceptual ideas of systems biology with clinical medicine. Complex cardiac diseases are clinical phenotypes generated by integration of genetic, molecular and environmental factors. Basic concepts of systems biology like network construction, modular thinking, biological constraints (downward biological direction and emergence (upward biological direction could be applied to clinical medicine. Especially, in the field of cardiology, these concepts can be used to explain complex clinical cardiac phenotypes like chronic heart failure and coronary artery disease. Cardiac diseases are biological complex entities which like other biological phenomena can be explained by a systems biology approach. The above powerful biological tools of systems biology can explain robustness growth and stability during disease process from modulation to phenotype. The purpose of the present review paper is to implement systems biology strategy and incorporate some conceptual issues raised by this approach into the clinical field of complex cardiac diseases. Cardiac disease process and progression can be addressed by the holistic realistic approach of systems biology in order to define in better terms earlier diagnosis and more effective therapy.

  9. What explains childhood violence? Micro correlates from VACS surveys.

    Science.gov (United States)

    Ravi, Shamika; Ahluwalia, Rahul

    2017-03-01

    Violence in childhood is a serious health, social and human rights concern globally, there is, however, little understanding about the factors that explain the various forms of violence in childhood. This paper uses data on childhood violence for 10,042 individuals from four countries. We report Odds Ratios from pooled logit regression analysis with country fixed effects model. There is no gender difference in the overall incidence of childhood violence. The data shows that 78% of girls and 79% of boys have suffered some form of violence before the age of 18 years. Odds of violence are higher among richer households, among individuals who have attended school and among individuals who have been married or in marriage-like arrangements. Individuals who justify wife beating have significantly higher likelihood of having faced violence themselves. Most perpetrators of violence against children - physical, emotional and sexual - are people known to them in their homes and community, and not strangers. There is limited understanding of the factors that explain violence in childhood. This study highlights some key factors that can explain this phenomenon.

  10. Face context advantage explained by vernier and separation discrimination acuity.

    Science.gov (United States)

    Vesker, Michael; Wilson, Hugh R

    2012-01-01

    Seeing facial features in the context of a full face is known to provide an advantage for perception. Using an interocular separation perception task we confirmed that seeing eyes within the context of a face improves discrimination in synthetic faces. We also show that this improvement of the face context can be explained using the presence of individual components of the face such as the nose mouth, or head-outline. We demonstrate that improvements due to the presence of the nose, and head-outline can be explained in terms of two-point separation measurements, obeying Weber's law as established in the literature. We also demonstrate that performance improvements due to the presence of the mouth can be explained in terms of Vernier acuity judgments between eye positions and the corners of the mouth. Overall, our study shows that the improvements in perception of facial features due to the face context effect can be traced to well understood basic visual measurements that may play a very general role in perceptual measurements of distance. Deficiencies in these measurements may also play a role in prosopagnosia. Additionally, we show interference of the eyebrows with the face-inversion effect for interocular discrimination.

  11. Avaliação da dor e morbidade local da retirada do enxerto ósseo da crista ilíaca para artrodese cervical anterior Evaluación del dolor y morbilidad local del injerto extraído de la cresta ilíaca para artrodesis cervical anterior Evaluation of the pain and local morbidity of the insertion taken out from the iliac crest to the anterior cervical arthrodesis

    Directory of Open Access Journals (Sweden)

    Rafael Barreto Silva

    2010-12-01

    Full Text Available OBJETIVO: avaliar as possíveis complicações associadas à retirada de enxerto da crista ilíaca anterior em cirurgia para artrodese cervical anterior, em especial a dor residual. MÉTODOS: foi realizado estudo retrospectivo com análise de prontuários e aplicação de questionário via telefone com 20 pacientes no período compreendido entre Agosto de 2008 e Novembro de 2009. Todos os pacientes foram submetidos à mesma técnica cirúrgica para extração do enxerto, sendo operados pela mesma equipe no Hospital de Clinicas da Unicamp (HC Unicamp. As variantes analisadas foram dor residual, taxa de infecção, lesão neurológica ou vascular e ocorrência de fratura da asa do ilíaco. Os dados foram colocados em uma tabela e as médias e porcentagens foram calculadas. RESULTADOS: dos 20 pacientes, 12 homens e 8 mulheres, com média de idade de 51,75 anos (29-74 e follow-up médio de 11,83 meses (2-29, não houve nenhuma lesão grave, como fratura, lesão arterial ou neurológica. Houve um caso de infecção superficial (5% e 25% dos pacientes queixaram-se de desconforto leve e dificuldade para deambular não incapacitante. CONCLUSÃO: a retirada de enxerto da crista ilíaca anterior está associada a muitas complicações, sendo importante o conhecimento de outras opções de enxerto e exposição ao paciente das possíveis complicações. Por meio deste levantamento, não verificamos nenhuma complicação grave, e o percentual de pacientes com dor residual acompanha os achados na literatura, podendo ser diminuído com uma dissecção cuidadosa da crista ilíaca.OBJETIVO: evaluar las posibles compilaciones asociadas a la retirada del injerto de la cresta ilíaca anterior en cirugía para artrodesis cervical anterior, principalmente los dolores residuales. MÉTODOS: fue realizado un estudio retrospectivo con análisis de prontuarios y con aplicación de cuestionario por teléfono para 20 pacientes entre agosto de 2008 y noviembre de 2009

  12. A three-species model explaining cyclic dominance of Pacific salmon.

    Science.gov (United States)

    Guill, Christian; Drossel, Barbara; Just, Wolfram; Carmack, Eddy

    2011-05-07

    The four-year oscillations of the number of spawning sockeye salmon (Oncorhynchus nerka) that return to their native stream within the Fraser River basin in Canada are a striking example of population oscillations. The period of the oscillation corresponds to the dominant generation time of these fish. Various-not fully convincing-explanations for these oscillations have been proposed, including stochastic influences, depensatory fishing, or genetic effects. Here, we show that the oscillations can be explained as an attractor of the population dynamics, resulting from a strong resonance near a Neimark Sacker bifurcation. This explains not only the long-term persistence of these oscillations, but also reproduces correctly the empirical sequence of salmon abundance within one period of the oscillations. Furthermore, it explains the observation that these oscillations occur only in sockeye stocks originating from large oligotrophic lakes, and that they are usually not observed in salmon species that have a longer generation time. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Deep Supervised, but Not Unsupervised, Models May Explain IT Cortical Representation

    Science.gov (United States)

    Khaligh-Razavi, Seyed-Mahdi; Kriegeskorte, Nikolaus

    2014-01-01

    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 IT requires

  14. 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

  15. Pathway switching explains the sharp response characteristic of hypoxia response network.

    Directory of Open Access Journals (Sweden)

    Yihai Yu

    2007-08-01

    Full Text Available Hypoxia induces the expression of genes that alter metabolism through the hypoxia-inducible factor (HIF. A theoretical model based on differential equations of the hypoxia response network has been previously proposed in which a sharp response to changes in oxygen concentration was observed but not quantitatively explained. That model consisted of reactions involving 23 molecular species among which the concentrations of HIF and oxygen were linked through a complex set of reactions. In this paper, we analyze this previous model using a combination of mathematical tools to draw out the key components of the network and explain quantitatively how they contribute to the sharp oxygen response. We find that the switch-like behavior is due to pathway-switching wherein HIF degrades rapidly under normoxia in one pathway, while the other pathway accumulates HIF to trigger downstream genes under hypoxia. The analytic technique is potentially useful in studying larger biomedical networks.

  16. 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/.

  17. Psychological Factors Explaining the Referral Behavior of Iranian Family Physicians

    Science.gov (United States)

    Mohaghegh, Bahram; Seyedin, Hesam; Rashidian, Arash; Ravaghi, Hamid; Khalesi, Nader; Kazemeini, Hossein

    2014-01-01

    Background: The recently developed policy of the family practice program in rural regions of Iran faced some challenges such as inefficient referral system. The health insurance organizations (purchaser) and health policy makers are concerned about the high rate of patient referrals from family physicians to specialists due to imposing unnecessary services and costs. Objectives: This study examined utility of the theory of planned behavior to explain intention of Iranian family physicians to reduce referral rate of patients with respiratory diseases to medical specialist. Patients and Methods: An exploratory cross-sectional study, employing a correlational design directed by the theory of planned behavior was conducted. A questionnaire was developed based on an eliciting study and review of literature. One hundred and seventy-four family physicians working at primary care centers in two provinces of Iran completed the questionnaire (response rate of 86%). Results: The finding revealed that intention of family physicians to reduce referral rate of patients to specialists was significantly related to two theory-based variables of subjective norms (r = 0.38, P < 0.001) and perceived behavioral control (r = 0.43, P < 0.001), and not to attitudes. A stepwise regression entering direct measures of the theory variables explained 35% of the variance on the intention, with perceived behavioral control being the strongest predictor. Adding background variables to the model achieved further 5% by variables of practice size and past referral rate behavior. Conclusions: The results indicated that psychological variables of the theory of planned behavior could explain a noticeable proportion of variance in family physician's intention to decrease the rate of referring patients with respiratory diseases to medical specialists. The intention is primarily influenced by normative and control considerations. These findings contribute to a better understanding of referral decisions by

  18. 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....... 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...

  19. 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

  20. 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.

  1. Explaining consumer attitudes to genetic modification in food production

    DEFF Research Database (Denmark)

    Bredahl, Lone

    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...... 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...

  2. Paternal Age Explains a Major Portion of De Novo Germline Mutation Rate Variability in Healthy Individuals.

    Directory of Open Access Journals (Sweden)

    Simon L Girard

    Full Text Available De novo mutations (DNM are an important source of rare variants and are increasingly being linked to the development of many diseases. Recently, the paternal age effect has been the focus of a number of studies that attempt to explain the observation that increasing paternal age increases the risk for a number of diseases. Using disease-free familial quartets we show that there is a strong positive correlation between paternal age and germline DNM in healthy subjects. We also observed that germline CNVs do not follow the same trend, suggesting a different mechanism. Finally, we observed that DNM were not evenly distributed across the genome, which adds support to the existence of DNM hotspots.

  3. Paternal Age Explains a Major Portion of De Novo Germline Mutation Rate Variability in Healthy Individuals

    Science.gov (United States)

    Bourassa, Cynthia V.; Lemieux Perreault, Louis-Philippe; Legault, Marc-André; Barhdadi, Amina; Ambalavanan, Amirthagowri; Brendgen, Mara; Vitaro, Frank; Noreau, Anne; Dionne, Ginette; Tremblay, Richard E.; Dion, Patrick A.; Boivin, Michel; Dubé, Marie-Pierre; Rouleau, Guy A.

    2016-01-01

    De novo mutations (DNM) are an important source of rare variants and are increasingly being linked to the development of many diseases. Recently, the paternal age effect has been the focus of a number of studies that attempt to explain the observation that increasing paternal age increases the risk for a number of diseases. Using disease-free familial quartets we show that there is a strong positive correlation between paternal age and germline DNM in healthy subjects. We also observed that germline CNVs do not follow the same trend, suggesting a different mechanism. Finally, we observed that DNM were not evenly distributed across the genome, which adds support to the existence of DNM hotspots. PMID:27723766

  4. Explaining occurrences of auroral kilometric radiation in Van Allen radiation belts

    Science.gov (United States)

    Xiao, Fuliang; Zhou, Qinghua; Su, Zhenpeng; He, Zhaoguo; Yang, Chang; Liu, Si; He, Yihua; Gao, Zhonglei

    2016-12-01

    Auroral kilometric radiation (AKR) is a strong terrestrial radio emission and dominates at higher latitudes because of reflection in vicinities of the source cavity and plasmapause. Recently, Van Allen Probes have observed occurrences of AKR emission in the equatorial region of Earth's radiation belts but its origin still remains an open question. Equatorial AKR can produce efficient acceleration of radiation belt electrons and is a risk to space weather. Here we report high-resolution observations during two small storm periods 4-6 April and 18-20 May 2013 and show, using a 3-D ray tracing simulation, that AKR can propagate downward all the way into the equatorial plane in the radiation belts under appropriate conditions. The simulated results can successfully explain the observed AKR's spatial distribution and frequency range, and the current results have a wide application to all other magnetized astrophysical objects in the universe.

  5. Antimatter: a gap soon explained?; Antimatiere: une disparition bientot expliquee?

    Energy Technology Data Exchange (ETDEWEB)

    Davidson, S. [Institut de Physique Nucleaire de Lyon, 69 (France)

    2011-04-15

    Antimatter exists, we can produce it in particle accelerators and detect it in cosmic radiations but antimatter stays very rare at the universe scale. The standard model does not explain this asymmetry, the excess of baryons (called also baryogenesis) might be a consequence of unknown particles and interactions that existed during the first moments after the Big-bang. 2 scenarios could explain baryogenesis: the first one is based on the annihilation of the massive particles that gives their tiny mass to the neutrinos through their interaction with the Higgs field. The second scenario is based on a possible separation of the weak interaction from the electromagnetic interaction that could have happened 10{sup -11} s after the Big-bang. This separation could have led to an excess of baryons through processes involving topological features called sphalerons. The existence of sphalerons is not inconsistent with the standard model. The second scenario could be tested at LHC when the accelerator reaches the TeV energy range. (A.C.)

  6. Explaining the footsteps, belly dancer, Wenceslas, and kickback illusions

    Science.gov (United States)

    Howe, Piers D. L.; Thompson, Peter G.; Anstis, Stuart M.; Sagreiya, Hersh; Livingstone, Margaret S.

    2009-01-01

    The footsteps illusion (FI) demonstrates that an object’s background can have a profound effect on the object’s perceived speed. This illusion consists of a yellow bar and a blue bar that move over a black-and-white, striped background. Although the bars move at a constant rate, they appear to repeatedly accelerate and decelerate in antiphase with each other. Previously, this illusion has been explained in terms of the variations in contrast at the leading and trailing edges of the bars that occur as the bars traverse the striped background. Here, we show that this explanation is inadequate and instead propose that for each bar, the bar’s leading edge, trailing edge, lateral edges, and the surrounding background edges all contribute to the bar’s perceived speed and that the degree to which each edge contributes to the motion percept is determined by that edge’s contrast. We show that this theory can explain all the data on the FI as well as the belly dancer and Wenceslas illusions. We conclude by presenting a new illusion, the kickback illusion, which, although geometrically similar to the FI, is mediated by a different mechanism, namely, reverse phi motion. PMID:17209742

  7. 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.

  8. Can evolutionary principles explain patterns of family violence?

    Science.gov (United States)

    Archer, John

    2013-03-01

    The article's aim is to evaluate the application of the evolutionary principles of kin selection, reproductive value, and resource holding power to the understanding of family violence. The principles are described in relation to specific predictions and the mechanisms underlying these. Predictions are evaluated for physical violence perpetrated by (a) parents to unrelated children, (b) parents to genetic offspring, and (c) offspring to parents and between (d) siblings and (e) sexual partners. Precise figures for risks have been calculated where possible. The major conclusions are that most of the evidence is consistent with evolutionary predictions derived from kin selection and reproductive value: There were (a) higher rates of violence to stepchildren, (b) a decline in violence with the age of offspring, and (c) an increase in violence with parental age, while (d) violence between siblings was generally at a low level and concerned resource disputes. The issue of distinguishing evolutionary from alternative explanations is addressed throughout and is problematic for predictions derived from reproductive value. The main evolutionary explanation for male partner violence, mate guarding as a result of paternity uncertainty, cannot explain Western studies where sex differences in control and violence between partners were absent, although other aspects of male partner violence are consistent with it, and it may explain sex differences in traditional cultures. Recurrent problems in evaluating the evidence were to control for possible confounds and thus to distinguish evolutionary from alternative explanations. Suggestions are outlined to address this and other issues arising from the review. © 2013 American Psychological Association

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

    Science.gov (United States)

    Ezaki, Takahiro; Horita, Yutaka; Takezawa, Masanori; Masuda, Naoki

    2016-07-01

    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. Leveraging population admixture to explain missing heritability of complex traits

    Science.gov (United States)

    Zaitlen, Noah; Pasaniuc, Bogdan; Sankararaman, Sriram; Bhatia, Gaurav; Zhang, Jianqi; Gusev, Alexander; Young, Taylor; Tandon, Arti; Pollack, Samuela; Vilhjálmsson, Bjarni J.; Assimes, Themistocles L.; Berndt, Sonja I.; Blot, William J.; Chanock, Stephen; Franceschini, Nora; Goodman, Phyllis G.; He, Jing; Hennis, Anselm JM; Hsing, Ann; Ingles, Sue A.; Isaacs, William; Kittles, Rick A.; Klein, Eric A.; Lange, Leslie A.; Nemesure, Barbara; Patterson, Nick; Reich, David; Rybicki, Benjamin A.; Stanford, Janet L.; Stevens, Victoria L; Strom, Sara S.; Whitsel, Eric A; Witte, John S.; Xu, Jianfeng; Haiman, Christopher; Wilson, James G.; Kooperberg, Charles; Stram, Daniel; Reiner, Alex P.; Tang, Hua; Price, Alkes L.

    2014-01-01

    Despite recent progress on estimating the heritability explained by genotyped SNPs (hg2), a large gap between hg2 and estimates of total narrow-sense heritability (h2) remains. Explanations for this gap include rare variants, or upward bias in family-based estimates of h2 due to shared environment or epistasis. We estimate h2 from unrelated individuals in admixed populations by first estimating the heritability explained by local ancestry (hγ2). We show that hγ2 = 2FSTCθ(1−θ)h2, where FSTC measures frequency differences between populations at causal loci and θ is the genome-wide ancestry proportion. Our approach is not susceptible to biases caused by epistasis or shared environment. We examined 21,497 African Americans from three cohorts, analyzing 13 phenotypes. For height and BMI, we obtained h2 estimates of 0.55 ± 0.09 and 0.23 ± 0.06, respectively, which are larger than estimates of hg2 in these and other data, but smaller than family-based estimates of h2. PMID:25383972

  11. Mycorrhizal status helps explain invasion success of alien plant species.

    Science.gov (United States)

    Menzel, Andreas; Hempel, Stefan; Klotz, Stefan; Moora, Mari; Pyšek, Petr; Rillig, Matthias C; Zobel, Martin; Kühn, Ingolf

    2017-01-01

    It is still debated whether alien plants benefit from being mycorrhizal, or if engaging in the symbiosis constrains their establishment and spread in new regions. We analyzed the association between mycorrhizal status of alien plant species in Germany and their invasion success. We compared whether the representation of species with different mycorrhizal status (obligate, facultative, or non-mycorrhizal) differed at several stages of the invasion process. We used generalized linear models to explain the occupied geographical range of alien plants, incorporating interactions of mycorrhizal status with plant traits related to morphology, reproduction, and life-history. Non-naturalized aliens did not differ from naturalized aliens in the relative frequency of different mycorrhizal status categories. Mycorrhizal status significantly explained the occupied range of alien plants; with facultative mycorrhizal species inhabiting a larger range than non-mycorrhizal aliens and obligate mycorrhizal plant species taking an intermediate position. Aliens with storage organs, shoot metamorphoses, or specialized structures promoting vegetative dispersal occupied a larger range when being facultative mycorrhizal. We conclude that being mycorrhizal is important for the persistence of aliens in Germany and constitutes an advantage compared to being non-mycorrhizal. Being facultative mycorrhizal seems to be especially advantageous for successful spread, as the flexibility of this mycorrhizal status may enable plants to use a broader set of ecological strategies. © 2016 by the Ecological Society of America.

  12. Bayesian optimal adaptation explains age-related human sensorimotor changes.

    Science.gov (United States)

    Karmali, Faisal; Whitman, Gregory T; Lewis, Richard F

    2017-11-08

    The brain uses information from different sensory systems to guide motor behavior, and aging is associated with a simultaneous decline in the quality of sensory information provided to the brain and a deterioration in motor control. Correlations between age-dependent decline in sensory anatomical structures and behavior have been demonstrated, and it has recently been suggested that a Bayesian framework could explain these relationships. Here we show that age-dependent changes in a human sensorimotor reflex, the vestibulo-ocular reflex, are explained by a Bayesian optimal adaptation in the brain occurring in response to death of motion-sensing hair cells. Specifically, we found that the temporal dynamics of the reflex as a function of age are predicted (r=0.93, pBayesian framework has been shown to be a general neural principle for multimodal sensory integration and dynamic sensory estimation, these findings provide evidence of longitudinal Bayesian processing over the human lifespan. These results illuminate how the aging brain strives to optimize motor behavior when faced with deterioration in the peripheral and central nervous system, and have implications in the field of vestibular and balance disorders, as they will likely provide guidance for physical therapy and for prosthetic aids that aim to reduce falls in the elderly. Copyright © 2017, Journal of Neurophysiology.

  13. 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).

  14. 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.

  15. 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 women before and after MAP Training. However, only in women did 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.

  16. Dynamical models explaining social balance and evolution of cooperation.

    Science.gov (United States)

    Traag, Vincent Antonio; Van Dooren, Paul; De Leenheer, Patrick

    2013-01-01

    Social networks with positive and negative links often split into two antagonistic factions. Examples of such a split abound: revolutionaries versus an old regime, Republicans versus Democrats, Axis versus Allies during the second world war, or the Western versus the Eastern bloc during the Cold War. Although this structure, known as social balance, is well understood, it is not clear how such factions emerge. An earlier model could explain the formation of such factions if reputations were assumed to be symmetric. We show this is not the case for non-symmetric reputations, and propose an alternative model which (almost) always leads to social balance, thereby explaining the tendency of social networks to split into two factions. In addition, the alternative model may lead to cooperation when faced with defectors, contrary to the earlier model. The difference between the two models may be understood in terms of the underlying gossiping mechanism: whereas the earlier model assumed that an individual adjusts his opinion about somebody by gossiping about that person with everybody in the network, we assume instead that the individual gossips with that person about everybody. It turns out that the alternative model is able to lead to cooperative behaviour, unlike the previous model.

  17. Dynamical models explaining social balance and evolution of cooperation.

    Directory of Open Access Journals (Sweden)

    Vincent Antonio Traag

    Full Text Available Social networks with positive and negative links often split into two antagonistic factions. Examples of such a split abound: revolutionaries versus an old regime, Republicans versus Democrats, Axis versus Allies during the second world war, or the Western versus the Eastern bloc during the Cold War. Although this structure, known as social balance, is well understood, it is not clear how such factions emerge. An earlier model could explain the formation of such factions if reputations were assumed to be symmetric. We show this is not the case for non-symmetric reputations, and propose an alternative model which (almost always leads to social balance, thereby explaining the tendency of social networks to split into two factions. In addition, the alternative model may lead to cooperation when faced with defectors, contrary to the earlier model. The difference between the two models may be understood in terms of the underlying gossiping mechanism: whereas the earlier model assumed that an individual adjusts his opinion about somebody by gossiping about that person with everybody in the network, we assume instead that the individual gossips with that person about everybody. It turns out that the alternative model is able to lead to cooperative behaviour, unlike the previous model.

  18. [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.

  19. Carcinogenesis explained within the context of a theory of organisms.

    Science.gov (United States)

    Sonnenschein, Carlos; Soto, Ana M

    2016-10-01

    For a century, the somatic mutation theory (SMT) has been the prevalent theory to explain carcinogenesis. According to the SMT, cancer is a cellular problem, and thus, the level of organization where it should be studied is the cellular level. Additionally, the SMT proposes that cancer is a problem of the control of cell proliferation and assumes that proliferative quiescence is the default state of cells in metazoa. In 1999, a competing theory, the tissue organization field theory (TOFT), was proposed. In contraposition to the SMT, the TOFT posits that cancer is a tissue-based disease whereby carcinogens (directly) and mutations in the germ-line (indirectly) alter the normal interactions between the diverse components of an organ, such as the stroma and its adjacent epithelium. The TOFT explicitly acknowledges that the default state of all cells is proliferation with variation and motility. When taking into consideration the principle of organization, we posit that carcinogenesis can be explained as a relational problem whereby release of the constraints created by cell interactions and the physical forces generated by cellular agency lead cells within a tissue to regain their default state of proliferation with variation and motility. Within this perspective, what matters both in morphogenesis and carcinogenesis is not only molecules, but also biophysical forces generated by cells and tissues. Herein, we describe how the principles for a theory of organisms apply to the TOFT and thus to the study of carcinogenesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Ability of matrix models to explain the past and predict the future of plant populations.

    Science.gov (United States)

    Crone, Elizabeth E; Ellis, Martha M; Morris, William F; Stanley, Amanda; Bell, Timothy; Bierzychudek, Paulette; Ehrlén, Johan; Kaye, Thomas N; Knight, Tiffany M; Lesica, Peter; Oostermeijer, Gerard; Quintana-Ascencio, Pedro F; Ticktin, Tamara; Valverde, Teresa; Williams, Jennifer L; Doak, Daniel F; Ganesan, Rengaian; McEachern, Kathyrn; Thorpe, Andrea S; Menges, Eric S

    2013-10-01

    Uncertainty associated with ecological forecasts has long been recognized, but forecast accuracy is rarely quantified. We evaluated how well data on 82 populations of 20 species of plants spanning 3 continents explained and predicted plant population dynamics. We parameterized stage-based matrix models with demographic data from individually marked plants and determined how well these models forecast population sizes observed at least 5 years into the future. Simple demographic models forecasted population dynamics poorly; only 40% of observed population sizes fell within our forecasts' 95% confidence limits. However, these models explained population dynamics during the years in which data were collected; observed changes in population size during the data-collection period were strongly positively correlated with population growth rate. Thus, these models are at least a sound way to quantify population status. Poor forecasts were not associated with the number of individual plants or years of data. We tested whether vital rates were density dependent and found both positive and negative density dependence. However, density dependence was not associated with forecast error. Forecast error was significantly associated with environmental differences between the data collection and forecast periods. To forecast population fates, more detailed models, such as those that project how environments are likely to change and how these changes will affect population dynamics, may be needed. Such detailed models are not always feasible. Thus, it may be wiser to make risk-averse decisions than to expect precise forecasts from models. © 2013 Society for Conservation Biology.

  1. Divergent biochemical fractionation, not convergent temperature, explains cellulose oxygen isotope enrichment across latitudes.

    Science.gov (United States)

    Sternberg, Leonel; Ellsworth, Patricia Fernandes Vendramini

    2011-01-01

    Recent findings based on the oxygen isotope ratios of tree trunk cellulose indicate that the temperature of biomass production in biomes ranging from boreal to subtropical forests converge to an average leaf temperature of 21.4°C. The above conclusion has been drawn under the assumption that biochemically related isotopic fractionations during cellulose synthesis are not affected by temperature. Here we test the above assumption by heterotrophically generating cellulose at different temperatures and measuring the proportion of carbohydrate oxygen that exchange with water during cellulose synthesis and the average biochemical fractionation associated with this exchange. We observed no variation in the proportion of oxygen that exchange with different temperatures, which averaged 0.42 as it has been observed in other studies. On the other hand, the biochemical oxygen isotope fractionation during cellulose synthesis is affected by temperature and can be described by a 2(nd) order polynomial equation. The biochemical fractionation changes little between temperatures of 20 and 30°C averaging 26‰ but increases at lower temperatures to values of 31‰. This temperature sensitive biochemical fractionation explains the pattern of cellulose oxygen isotope ratios of aquatic plants encompassing several latitudes. The observed temperature sensitive biochemical fractionation also indicates that divergent biochemical fractionation and not convergent leaf temperature explains the increase in oxygen isotope enrichment of cellulose across several biomes.

  2. Using Relative Utility Pricing to Explain Multibuy Prices in Supermarkets and on the Internet

    OpenAIRE

    Thomas, P; Chrystal, A.

    2013-01-01

    The Relative Utility Pricing (RUP) model is used to explain the prices for commodities being sold in supermarkets and on the internet. Grocery prices offered by the supermarkets, Tesco, Sainsbury and Waitrose in December 2009 and August 2013, are considered, as well as the prices of electronic items offered by Amazon on the internet at the same dates. The observed price for a pack can be given an explanation in terms of its size relative to the smallest pack considered by the customer (the ba...

  3. Relational Regulation Theory : A New Approach to Explain the Link Between Perceived Social Support and Mental Health

    NARCIS (Netherlands)

    Lakey, Brian; Orehek, Edward

    Perceived support is consistently linked to good mental health, which is typically explained as resulting from objectively supportive actions that buffer stress. Yet this explanation has difficulty accounting for the often-observed main effects between support and mental health. Relational

  4. Explaining the level of credit spreads: Option-implied jump risk premia in a firm value model

    NARCIS (Netherlands)

    Cremers, K.J.M.; Driessen, J.; Maenhout, P.

    2008-01-01

    We study whether option-implied jump risk premia can explain the high observed level of credit spreads. We use a structural jump-diffusion firm value model to assess the level of credit spreads generated by option-implied jump risk premia. Prices and returns of equity index and individual options

  5. 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.)

  6. 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.   

  7. 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...

  8. Rhythmic Degradation Explains and Unifies Circadian Transcriptome and Proteome Data

    Directory of Open Access Journals (Sweden)

    Sarah Lück

    2014-10-01

    Full Text Available The rich mammalian cellular circadian output affects thousands of genes in many cell types and has been the subject of genome-wide transcriptome and proteome studies. The results have been enigmatic because transcript peak abundances do not always follow the peaks of gene-expression activity in time. We posited that circadian degradation of mRNAs and proteins plays a pivotal role in setting their peak times. To establish guiding principles, we derived a theoretical framework that fully describes the amplitudes and phases of biomolecules with circadian half-lives. We were able to explain the circadian transcriptome and proteome studies with the same unifying theory, including cases in which transcripts or proteins appeared before the onset of increased production rates. Furthermore, we estimate that 30% of the circadian transcripts in mouse liver and Drosophila heads are affected by rhythmic posttranscriptional regulation.

  9. Doing business with CERN: a new website explains everything

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    At CERN, procuring all supplies and services is the job of the Procurement and Industrial Services (PI) group of the Finance and Procurement Department. Managing about 30,000 new orders and contracts every year, the Group recently launched a brand-new website where CERN and its external partners can find all the useful information to effectively do business together.   When the Laboratory needs to buy goods or services, the PI group comes into play and makes sure that this happens according to the established rules and procedures. “CERN procures supplies and services and awards orders and contracts in compliance with the principles of transparency and impartiality,” explains Anders Unnervik, Head of Procurement and Industrial Services in the Finance and Procurement Department (FP). “CERN’s tendering procedures are selective but they are designed to guarantee fair competition.” The invitations to tender are, in principle, limited to firms establish...

  10. 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.

  11. Can the photosynthesis first step quantum mechanism be explained?

    CERN Document Server

    Sacilotti, Marco; Mota, Claudia C B O; Nunes, Frederico Dias; Gomes, Anderson S L

    2010-01-01

    Photosynthesis first step mechanism concerns the sunlight absorption and both negative and positive charges separation. Recent and important photosynthesis literature claims that this mechanism is quantum mechanics controlled, however without presenting qualitative or quantitative scientifically based mechanism. The present accepted and old-fashioned photosynthesis mechanism model suffers from few drawbacks and an important issue is the absence of driving force for negative and positive charges separation. This article presents a new qualitative model for this first step mechanism in natural catalytic systems such as photosynthesis in green leaves. The model uses a concept of semiconductor band gap engineering, such as the staggered energy band gap line-up in semiconductors. To explain the primary mechanism in natural photosynthesis the proposal is the following: incident light is absorbed inside the leaves causing charges separation. The only energetic configuration that allows charges separation under illum...

  12. Real world ocean rogue waves explained without the modulational instability

    Science.gov (United States)

    Fedele, Francesco; Brennan, Joseph; Ponce de León, Sonia; Dudley, John; Dias, Frédéric

    2016-01-01

    Since the 1990s, the modulational instability has commonly been used to explain the occurrence of rogue waves that appear from nowhere in the open ocean. However, the importance of this instability in the context of ocean waves is not well established. This mechanism has been successfully studied in laboratory experiments and in mathematical studies, but there is no consensus on what actually takes place in the ocean. In this work, we question the oceanic relevance of this paradigm. In particular, we analyze several sets of field data in various European locations with various tools, and find that the main generation mechanism for rogue waves is the constructive interference of elementary waves enhanced by second-order bound nonlinearities and not the modulational instability. This implies that rogue waves are likely to be rare occurrences of weakly nonlinear random seas. PMID:27323897

  13. Can Nomenclature for the Body be Explained by Embodiment Theories?

    Science.gov (United States)

    Majid, Asifa; van Staden, Miriam

    2015-10-01

    According to widespread opinion, the meaning of body part terms is determined by salient discontinuities in the visual image; such that hands, feet, arms, and legs, are natural parts. If so, one would expect these parts to have distinct names which correspond in meaning across languages. To test this proposal, we compared three unrelated languages-Dutch, Japanese, and Indonesian-and found both naming systems and boundaries of even basic body part terms display variation across languages. Bottom-up cues alone cannot explain natural language semantic systems; there simply is not a one-to-one mapping of the body semantic system to the body structural description. Although body parts are flexibly construed across languages, body parts semantics are, nevertheless, constrained by non-linguistic representations in the body structural description, suggesting these are necessary, although not sufficient, in accounting for aspects of the body lexicon. Copyright © 2015 Cognitive Science Society, Inc.

  14. 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.

  15. Hypothesis to explain childhood cancer near nuclear power plants.

    Science.gov (United States)

    Fairlie, Ian

    2010-01-01

    As reported in this journal in 2009, the 2008 KiKK study in Germany found a 60% increase in all cancers and a 120% increase in leukemias among children living within 5 km of all German nuclear power stations. The KiKK study has triggered debates as to the cause(s) of these increased cancers. This article discusses the available evidence of leukemias near nuclear installations around the world. Over 60 epidemiological studies exist, the large majority of which indicate increases in leukemia incidence. The article also outlines a possible biological mechanism to explain the increased cancers, suggesting that doses from environmental nuclear power plant emissions to embryos/ fetuses in pregnant women near the plants may be larger than suspected, and that hemopoietic tissues may be considerably more radiosensitive in embryos/ fetuses than in newborn babies. The article concludes with recommendations for further research.

  16. [To explain is to narrate. How to visualize scientific data].

    Science.gov (United States)

    Hawtin, Nigel

    2014-01-01

    When you try to appeal a vast ranging audience, as it occurs at the New Scientist that addresses scientists as well as the general public, your scientific visual explainer must be succinct, clear, accurate and easily understandable. In order to reach this goal, your message should provide only the main data, the ones that allow you to balance information and clarity: information should be put into context and all the extra details should be cut down. It is very important, then, to know well both your audience and the subject you are going to describe, as graphic masters of the past, like William Playfair and Charles Minard, have taught us. Moreover, you should try to engage your reader connecting the storytelling power of words and the driving force of the graphics: colours, visual elements, typography. To be effective, in fact, an infographic should not only be truthful and functional, but also elegant, having style and legibility.

  17. [Nurses are not into personal marketing: do history explain why?].

    Science.gov (United States)

    Gentil, Rosana Chami

    2009-01-01

    Reflection on the nurse's personal marketing based on beliefs and values explained by the history of the main characters that care for patients. It brings to the surface reflections on the ambiguity between the social image of nursing and scientific, technological and humanistic knowledge developed over the time. It recognizes that there is still a fixation on the attributes relating to attitude and moral of the professionals to the detriment of having high regard for the technical and scientific knowledge. It verifies that the History of Nursing allows understanding that the fight against prejudice in the collective imagination lends weight to the social acceptance and recognition of this profession through the promotion of Nursing Science and the demonstration of its application in the professional practice.

  18. Modern elementary particle physics explaining and extending the standard model

    CERN Document Server

    Kane, Gordon

    2017-01-01

    This book is written for students and scientists wanting to learn about the Standard Model of particle physics. Only an introductory course knowledge about quantum theory is needed. The text provides a pedagogical description of the theory, and incorporates the recent Higgs boson and top quark discoveries. With its clear and engaging style, this new edition retains its essential simplicity. Long and detailed calculations are replaced by simple approximate ones. It includes introductions to accelerators, colliders, and detectors, and several main experimental tests of the Standard Model are explained. Descriptions of some well-motivated extensions of the Standard Model prepare the reader for new developments. It emphasizes the concepts of gauge theories and Higgs physics, electroweak unification and symmetry breaking, and how force strengths vary with energy, providing a solid foundation for those working in the field, and for those who simply want to learn about the Standard Model.

  19. 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).

  20. Explaining drug policy: Towards an historical sociology of policy change.

    Science.gov (United States)

    Seddon, Toby

    2011-11-01

    The goal of seeking to understand the development over time of drug policies is a specific version of the more general intellectual project of finding ways of explaining social change. The latter has been a preoccupation of some of the greatest thinkers within the social sciences of the last 200 years, from Foucault all the way back to the three nineteenth-century pioneers, Marx, Durkheim and Weber. I describe this body of work as 'historical sociology'. In this paper, I outline how a particular approach to historical sociology can be fruitfully drawn upon to understand the development of drug policy, using by way of illustration the example of the analysis of a recent transformation in British drug policy: the rise of the criminal justice agenda. I conclude by arguing that by looking at developments in drug policy in this way, some new insights are opened up. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Focused Observations: How to Observe Young Children for Assessment and Curriculum Planning, Second Edition

    Science.gov (United States)

    Gronlund, Gaye; James, Marlyn

    2013-01-01

    Intentional teaching begins with focused observations and systematic documentation of children's learning and development. "Focused Observations, Second Edition," explains why observation is one of the best methods to get to know each child well, track progress, and plan individualized curriculum. It also provides tools and techniques to…

  2. Observing inflationary reheating.

    Science.gov (United States)

    Martin, Jérôme; Ringeval, Christophe; Vennin, Vincent

    2015-02-27

    Reheating is the epoch which connects inflation to the subsequent hot big-bang phase. Conceptually very important, this era is, however, observationally poorly known. We show that the current Planck satellite measurements of the cosmic microwave background (CMB) anisotropies constrain the kinematic properties of the reheating era for most of the inflationary models. This result is obtained by deriving the marginalized posterior distributions of the reheating parameter for about 200 models of slow-roll inflation. Weighted by the statistical evidence of each model to explain the data, we show that the Planck 2013 measurements induce an average reduction of the posterior-to-prior volume by 40%. Making some additional assumptions on reheating, such as specifying a mean equation of state parameter, or focusing the analysis on peculiar scenarios, can enhance or reduce this constraint. Our study also indicates that the Bayesian evidence of a model can substantially be affected by the reheating properties. The precision of the current CMB data is therefore such that estimating the observational performance of a model now requires incorporating information about its reheating history.

  3. Infrastructure features outperform environmental variables explaining rabbit abundance around motorways.

    Science.gov (United States)

    Planillo, Aimara; Malo, Juan E

    2018-01-01

    Human disturbance is widespread across landscapes in the form of roads that alter wildlife populations. Knowing which road features are responsible for the species response and their relevance in comparison with environmental variables will provide useful information for effective conservation measures. We sampled relative abundance of European rabbits, a very widespread species, in motorway verges at regional scale, in an area with large variability in environmental and infrastructure conditions. Environmental variables included vegetation structure, plant productivity, distance to water sources, and altitude. Infrastructure characteristics were the type of vegetation in verges, verge width, traffic volume, and the presence of embankments. We performed a variance partitioning analysis to determine the relative importance of two sets of variables on rabbit abundance. Additionally, we identified the most important variables and their effects model averaging after model selection by AICc on hypothesis-based models. As a group, infrastructure features explained four times more variability in rabbit abundance than environmental variables, being the effects of the former critical in motorway stretches located in altered landscapes with no available habitat for rabbits, such as agricultural fields. Model selection and Akaike weights showed that verge width and traffic volume are the most important variables explaining rabbit abundance index, with positive and negative effects, respectively. In the light of these results, the response of species to the infrastructure can be modulated through the modification of motorway features, being some of them manageable in the design phase. The identification of such features leads to suggestions for improvement through low-cost corrective measures and conservation plans. As a general indication, keeping motorway verges less than 10 m wide will prevent high densities of rabbits and avoid the unwanted effects that rabbit populations

  4. Maternal characteristics largely explain poor pregnancy outcome after hyperemesis gravidarum.

    Science.gov (United States)

    Roseboom, Tessa J; Ravelli, Anita C J; van der Post, Joris A; Painter, Rebecca C

    2011-05-01

    To describe the characteristics of women who suffer from hyperemesis gravidarum, and explore the independent effect of hyperemesis gravidarum on pregnancy outcome. In The Netherlands Perinatal Registry, we used all data on singleton pregnancies of at least 24 weeks and 500 g without congenital anomalies in the years 2000-2006. We examined the characteristics of women who suffered from hyperemesis gravidarum and their children. Women who suffered from hyperemesis gravidarum were slightly younger; more often primiparous, of lower socio-economic status, of non-Western descent and substance abusers; had more often conceived through assisted reproduction techniques and more often had pre-existing hypertension, diabetes mellitus and psychiatric diseases than women who did not suffer from hyperemesis gravidarum. Also, their pregnancies were more often complicated by hypertension and diabetes and they more often carried a female fetus. Pregnancies complicated by hyperemesis gravidarum significantly more often had an adverse outcome (prematurity or birth weight below the 10th percentile). The increased risk of adverse pregnancy outcomes after hyperemesis gravidarum was largely explained by the differences in maternal characteristics (crude OR 1.22 (95% CI 1.10-1.36), adjusted OR was 1.07 (95% CI 0.95-1.19)). Hyperemesis gravidarum is associated with adverse pregnancy outcomes. This is largely explained by differences in maternal characteristics. Given the impact of the early environment on later health (which is independent of size at birth), studies that aim to assess the long-term consequences of hyperemesis gravidarum need to be given high priority. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  5. 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.

  6. 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

  7. Explained Variation and Predictive Accuracy with an Extension to the Competing Risks Model

    DEFF Research Database (Denmark)

    Rosthøj, Susanne; Keiding, Niels

    2003-01-01

    Competing risks; efficiency; explained variation; misspecification; predictive accuracy; survival analysis......Competing risks; efficiency; explained variation; misspecification; predictive accuracy; survival analysis...

  8. THE IMPLEMENTATION OF POE (PREDICT OBSERVE EXPLAIN MODEL TO IMPROVE STUDENT’S CONCEPT UNDERSTANDING ON NEWTON’S LAW

    Directory of Open Access Journals (Sweden)

    Haris Rosdianto

    2017-06-01

    Full Text Available The aim of this study is to determine the improvement of student’s concept understanding on Newton's Law with the implementation of POE learning model. This research type is quantitative and using pre-experiment method with one group pre-test post-test design. In this study, the measurements in the form of pre-test to the subject and then treated with the POE learning model and within a certain time post-test is given. The population in this research is all students of class VIII in SMP 5 Singkawang city. The sample of the research is the students of class VIII E which amounted to 20 people and the sampling technique using purposive sampling. The result of data analysis using N-gain equation shows improvement of student’s concept understanding by 0,64 with medium category.

  9. Responses in sediment bioassays used in the Netherlands: can observed toxicity be explained by routinely monitored priority pollutants?

    NARCIS (Netherlands)

    Lahr, J.; Maas-Diepeveen, J.L.; Stuijfzand, S.C.; Leonards, P.E.G.; Drueke, J.M.; Luecker, S.; Espeldoorn, A.

    2003-01-01

    In order to identify the cause of toxicity in sediments and suspended matter, a large number of samples with different degrees of contamination was taken at various locations in The Netherlands. Standard acute bioassays were carried out with the bacterium Vibrio fischeri, the rotifer Brachionus

  10. Can Vertical Migrations of Dinoflagellates Explain Observed Bioluminescence Patterns During an Upwelling Event in Monterey Bay, California?

    Science.gov (United States)

    2012-01-25

    of actual dinoflagellates swimming during the 2003 upwelling event represents a very challenging task and requires knowledge of their initial...Solid vertical lines indicate location of the Ml mooring. profiles derived from the Modular Ocean Data Assimilation System ( MODAS ) [Fox et al, 2002...to avoid strong advection by southward flow along the entrance to the Bay. [28] We want to stress here that the actual dinoflagellates swimming

  11. Do Differences in Exposures Explain the Observed Heterogeneity in PM2.5 - Mortality Associations across U.S. cities?

    Science.gov (United States)

    This analysis evaluates exposure factors as potential determinants of the heterogeneity in city-specific associations between PM2.5 and mortality. Exposure factor variables were created based on housing characteristics, commuting patterns, heating fuel usage, and climatic factors...

  12. Noncoding after All: Biases in Proteomics Data Do Not Explain Observed Absence of lncRNA Translation Products.

    Science.gov (United States)

    Verheggen, Kenneth; Volders, Pieter-Jan; Mestdagh, Pieter; Menschaert, Gerben; Van Damme, Petra; Gevaert, Kris; Martens, Lennart; Vandesompele, Jo

    2017-07-07

    Over the past decade, long noncoding RNAs (lncRNAs) have emerged as novel functional entities of the eukaryotic genome. However, the scientific community remains divided over the amount of true noncoding transcripts among the large number of unannotated transcripts identified by recent large scale and deep RNA-sequencing efforts. Here, we systematically exclude possible technical reasons underlying the absence of lncRNA-encoded proteins in mass spectrometry data sets, strongly suggesting that the large majority of lncRNAs is indeed not translated.

  13. Explaining the catch efficiency of different cod pots using underwater video to observe cod entry and exit behaviour

    DEFF Research Database (Denmark)

    Hedgärde, Maria; Berg, Casper Willestofte; Kindt-Larsen, Lotte

    2016-01-01

    and results showed an increase in entry rates during the night time, suggesting that lights attract fish to the pot when the dark surroundings make the effect of the light more noticeable. Exit rates in trial 1 increased with an increasing number of fish in the pot while they decreased with soak time...

  14. Teaching Enzymes to Pre-Service Science Teachers through POE (Predict, Observe, Explain) Method: The Case of Catalase

    Science.gov (United States)

    Güngör, Sema Nur; Özkan, Muhlis

    2016-01-01

    The aim of this study is to teach enzymes, which are one of the biology subjects in understanding which students have a big difficulty, to pre-service teachers through POE method in the case of catalase, which is an oxidoreductase. Descriptive analysis method was employed in this study in which 38 second grade pre-service teachers attending Uludag…

  15. Delayed response and biosonar perception explain movement coordination in trawling bats.

    Directory of Open Access Journals (Sweden)

    Luca Giuggioli

    2015-03-01

    Full Text Available Animal coordinated movement interactions are commonly explained by assuming unspecified social forces of attraction, repulsion and alignment with parameters drawn from observed movement data. Here we propose and test a biologically realistic and quantifiable biosonar movement interaction mechanism for echolocating bats based on spatial perceptual bias, i.e. actual sound field, a reaction delay, and observed motor constraints in speed and acceleration. We found that foraging pairs of bats flying over a water surface swapped leader-follower roles and performed chases or coordinated manoeuvres by copying the heading a nearby individual has had up to 500 ms earlier. Our proposed mechanism based on the interplay between sensory-motor constraints and delayed alignment was able to recreate the observed spatial actor-reactor patterns. Remarkably, when we varied model parameters (response delay, hearing threshold and echolocation directionality beyond those observed in nature, the spatio-temporal interaction patterns created by the model only recreated the observed interactions, i.e. chases, and best matched the observed spatial patterns for just those response delays, hearing thresholds and echolocation directionalities found to be used by bats. This supports the validity of our sensory ecology approach of movement coordination, where interacting bats localise each other by active echolocation rather than eavesdropping.

  16. Explaining extreme ground motion in Osaka basin during the 2011 Tohoku earthquake

    Science.gov (United States)

    Tsai, Victor C.; Bowden, Daniel C.; Kanamori, Hiroo

    2017-07-01

    Despite being 770 km away from the epicenter, observed ground motions due to the Tohoku earthquake in the Osaka Basin were unexpectedly large, with an amplification of more than a factor of 20 compared to immediately outside the basin, and including 2.7 m peak-to-peak roof displacements at one high-rise building. The local ground motions exceeded expectations based on standard computations of site response by a factor of 3, predicted frequencies of peak acceleration were off by at least 50%, and such discrepancies have not yet been explained quantitatively. Here we show that utilizing semianalytic theory for surface-wave amplification, we are able to accurately predict both the amplitudes and frequencies of large ground amplification in the Osaka Basin using only knowledge of the local one-dimensional structure. Comparison between this simple prediction and observed amplification was not expected to be so favorable and suggests that simple one-dimensional surface-wave site amplification factors can be useful in the absence of full three-dimensional wave propagation simulations. Such surface-wave amplification factors can be included in addition to the standard measures of site-specific site amplification and should help explain strong ground motion variability in future large earthquakes that shake Osaka Basin and elsewhere in the world.

  17. A model explaining synchronization of neuron bioelectric frequency under weak alternating low frequency magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Moral, A. del, E-mail: delmoral@unizar.es [Laboratorio de Magnetismo, Departamento de Física de Materia Condensada and Instituto de Ciencia de Materiales, Universidad de Zaragoza and Consejo Superior de Investigaciones Científicas, 50009 Zaragoza (Spain); Laboratorio de Magnetobiología, Departamento de Anatomía e Histología, Facultad de Medicina, Universidad de Zaragoza, 50009 Zaragoza (Spain); Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Madrid (Spain); Azanza, María J., E-mail: mjazanza@unizar.es [Laboratorio de Magnetobiología, Departamento de Anatomía e Histología, Facultad de Medicina, Universidad de Zaragoza, 50009 Zaragoza (Spain); Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, 28223 Madrid (Spain)

    2015-03-01

    A biomagnetic-electrical model is presented that explains rather well the experimentally observed synchronization of the bioelectric potential firing rate (“frequency”), f, of single unit neurons of Helix aspersa mollusc under the application of extremely low frequency (ELF) weak alternating (AC) magnetic fields (MF). The proposed model incorporates to our widely experimentally tested model of superdiamagnetism (SD) and Ca{sup 2+} Coulomb explosion (CE) from lipid (LP) bilayer membrane (SD–CE model), the electrical quadrupolar long range interaction between the bilayer LP membranes of synchronized neuron pairs, not considered before. The quadrupolar interaction is capable of explaining well the observed synchronization. Actual extension of our SD–CE-model shows that the neuron firing frequency field, B, dependence becomes not modified, but the bioelectric frequency is decreased and its spontaneous temperature, T, dependence is modified. A comparison of the model with synchronization experimental results of pair of neurons under weak (B{sub 0}≅0.2–15 mT) AC-MF of frequency f{sub M}=50 Hz is reported. From the deduced size of synchronized LP clusters under B, is suggested the formation of small neuron networks via the membrane lipid correlation. - Highlights: • Neuron pair synchronization under low frequency alternating (AC) magnetic field (MF). • Superdiamagnetism and Ca{sup 2+} Coulomb explosion for AC MF effect in synchronized frequency. • Membrane lipid electrical quadrupolar pair interaction as synchronization mechamism. • Good agreement of model with electrophysiological experiments on mollusc Helix neurons.

  18. Climate change but not unemployment explains the changing suicidality in Thessaloniki Greece (2000-2012).

    Science.gov (United States)

    Fountoulakis, Konstantinos N; Savopoulos, Christos; Zannis, Prodromos; Apostolopoulou, Martha; Fountoukidis, Ilias; Kakaletsis, Nikolaos; Kanellos, Ilias; Dimellis, Dimos; Hyphantis, Thomas; Tsikerdekis, Athanasios; Pompili, Maurizio; Hatzitolios, Apostolos I

    2016-03-15

    Recently there was a debate concerning the etiology behind attempts and completed suicides. The aim of the current study was to search for possible correlations between the rates of attempted and completed suicide and climate variables and regional unemployment per year in the county of Thessaloniki, Macedonia, northern Greece, for the years 2000-12. The regional rates of suicide and attempted suicide as well as regional unemployment were available from previous publications of the authors. The climate variables were calculated from the daily E-OBS gridded dataset which is based on observational data Only the male suicide rates correlate significantly with high mean annual temperature but not with unemployment. The multiple linear regression analysis results suggest that temperature is the only variable that determines male suicides and explains 51% of their variance. Unemployment fails to contribute significantly to the model. There seems to be a seasonal distribution for attempts with mean rates being higher for the period from May to October and the rates clearly correlate with temperature. The highest mean rates were observed during May and August and the lowest during December and February. Multiple linear regression analysis suggests that temperature also determines the female attempts rate although the explained variable is significant but very low (3-5%) Climate variables and specifically high temperature correlate both with suicide and attempted suicide rates but with a different way between males and females. The climate effect was stronger than the effect of unemployment. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. A model explaining synchronization of neuron bioelectric frequency under weak alternating low frequency magnetic field

    Science.gov (United States)

    del Moral, A.; Azanza, María J.

    2015-03-01

    A biomagnetic-electrical model is presented that explains rather well the experimentally observed synchronization of the bioelectric potential firing rate ("frequency"), f, of single unit neurons of Helix aspersa mollusc under the application of extremely low frequency (ELF) weak alternating (AC) magnetic fields (MF). The proposed model incorporates to our widely experimentally tested model of superdiamagnetism (SD) and Ca2+ Coulomb explosion (CE) from lipid (LP) bilayer membrane (SD-CE model), the electrical quadrupolar long range interaction between the bilayer LP membranes of synchronized neuron pairs, not considered before. The quadrupolar interaction is capable of explaining well the observed synchronization. Actual extension of our SD-CE-model shows that the neuron firing frequency field, B, dependence becomes not modified, but the bioelectric frequency is decreased and its spontaneous temperature, T, dependence is modified. A comparison of the model with synchronization experimental results of pair of neurons under weak (B0 ≅0.2-15 mT) AC-MF of frequency fM=50 Hz is reported. From the deduced size of synchronized LP clusters under B, is suggested the formation of small neuron networks via the membrane lipid correlation.

  20. Are Traits Useful? Explaining Trait Manifestations as Tools in the Pursuit of Goals

    Science.gov (United States)

    McCabe, Kira O.; Fleeson, William

    2015-01-01

    Traits and motivation mainly have been treated separately for almost a century. The purpose of these studies is to test the proposal that traits and motivation are intricately linked. Specifically, that one explanation for traits, at least in terms of their descriptiveness of what people actually do, is the goals people pursue. Study 1 used experience-sampling methodology to show that almost half the variance in extraversion and conscientiousness manifestation was explained by goal pursuit differences. Both why people enacted more of extraversion and/or conscientiousness than others, and why people enacted extraversion and/or conscientiousness at any given moment were explained by the goals people were pursuing at those moments. Study 2 used experimental methodology to show that extraversion and conscientiousness enactment was in fact caused by the goal pursuit. Study 3 employed observer ratings to show that the goal-dependent enactments of traits were observer-verified actual behaviors. In all three studies, different goals affected different traits discriminatively. Thus, these findings provided strong evidence for one explanation of traits, that they are useful for accomplishing goals. These findings provided one answer to long-standing questions about the conceptual relations between traits and motivation. And these findings clarified the meaning and nature of extraversion and conscientiousness by revealing part of what these traits are for. PMID:26280839

  1. [Eugenic abortion could explain the lower infant mortality in Cuba compared to that in Chile].

    Science.gov (United States)

    Donoso S, Enrique; Carvajal C, Jorge A

    2012-08-01

    Cuba and Chile have the lower infant mortality rates of Latin America. Infant mortality rate in Cuba is similar to that of developed countries. Chilean infant mortality rate is slightly higher than that of Cuba. To investigate if the lower infant mortality rate in Cuba, compared to Chile, could be explained by eugenic abortion, considering that abortion is legal in Cuba but not in Chile. We compared total and congenital abnormalities related infant mortality in Cuba and Chile during 2008, based on vital statistics of both countries. In 2008, infant mortality rates in Chile were significantly higher than those of Cuba (7.8 vs. 4.7 per 1,000 live born respectively, odds ratio (OR) 1.67; 95% confidence intervals (Cl) 1.52-1.83). Congenital abnormalities accounted for 33.8 and 19.2% of infant deaths in Chile and Cuba, respectively. Discarding infant deaths related to congenital abnormalities, infant mortality rate continued to be higher in Chile than in Cuba (5.19 vs. 3.82 per 1000 live born respectively, OR 1.36; 95%CI 1.221.52). Considering that antenatal diagnosis is widely available in both countries, but abortion is legal in Cuba but not in Chile, we conclude that eugenic abortion may partially explain the lower infant mortality rate observed in Cuba compared to that observed in Chile.

  2. 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

    2015-03-16

    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.

  3. Simple model to explain instabilities in passively-phased high-power fiber laser arrays

    Energy Technology Data Exchange (ETDEWEB)

    Bochove, Erik J. [Air Force Research Laboratory, Kirtland Air Force Base, NM; Shakir, Sami A. [TASC, Inc.; Aceves, Alejandro B. [Southern Methodist University, Dallas; Braiman, Yehuda [ORNL; Deiterding, Ralf [ORNL; Miller, Casey A [ORNL; Colet, Pere R. [University of the Balearic Islands, Palma de Mallorca, Spain; Jacobo, Adrian [University of the Balearic Islands, Palma de Mallorca, Spain; Rhodes, Charles [Liberations Systems Management, Inc.

    2011-01-01

    We propose a simple physical mechanism to explain observed instabilities in the dynamics of passively phased fiber amplifier arrays that arises from two properties: First that a weak phase disturbance of the output field of the array is converted into a strong intensity disturbance through the mode-selective feedback mechanism. Second, that this intensity fluctuation regenerates a phase fluctuation due to the nonlinear properties of the amplifying media. At sufficiently high operating power levels this cyclic disturbance continues to grow upon each cavity round trip, creating instability. This simple picture is supported by the results of a linear stability analysis of the set of propagation and population rate equations, which are in good agreement with observed critical power levels. A third level of quantitative confirmation was obtained by comparison to the results of numerical integration of the original set of nonlinear equations. This predicted instability is entirely a property of passively phased arrays of more than one element.

  4. Explaining the Gender Wage Gap in STEM: Does Field Sex Composition Matter?

    Directory of Open Access Journals (Sweden)

    Katherine Michelmore

    2016-08-01

    Full Text Available Using the National Science Foundation's SESTAT data, we examine the gender wage gap by race among those working in computer science, life sciences, physical sciences, and engineering. We find that in fields with a greater representation of women (the life and physical sciences, the gender wage gap can largely be explained by differences in observed characteristics between men and women working in those fields. In the fields with the lowest concentration of women (computer science and engineering, gender wage gaps persist even after controlling for observed characteristics. In assessing how this gap changes over time, we find evidence of a narrowing for more recent cohorts of college graduates in the life sciences and engineering. The computer sciences and physical sciences, however, show no clear pattern in the gap across cohorts of graduates.

  5. Leaf development and demography explain photosynthetic seasonality in Amazon evergreen forests

    Science.gov (United States)

    Wu, Jin; Albert, Lauren; Lopes, Aline; Restrepo-Coupe, Natalia; Hayek, Matthew; Wiedemann, Kenia T.; Guan, Kaiyu; Stark, Scott C.; Christoffersen, Bradley; Prohaska, Neill; Tavares, Julia V.; Marostica, Suelen; Kobayashi, Hideki; Ferreira, Maurocio L.; Campos, Kleber Silva; da Silva, Rodrigo; Brando, Paulo M.; Dye, Dennis G.; Huxman, Travis E.; Huete, Alfredo; Nelson, Bruce; Saleska, Scott

    2016-01-01

    In evergreen tropical forests, the extent, magnitude, and controls on photosynthetic seasonality are poorly resolved and inadequately represented in Earth system models. Combining camera observations with ecosystem carbon dioxide fluxes at forests across rainfall gradients in Amazônia, we show that aggregate canopy phenology, not seasonality of climate drivers, is the primary cause of photosynthetic seasonality in these forests. Specifically, synchronization of new leaf growth with dry season litterfall shifts canopy composition toward younger, more light-use efficient leaves, explaining large seasonal increases (~27%) in ecosystem photosynthesis. Coordinated leaf development and demography thus reconcile seemingly disparate observations at different scales and indicate that accounting for leaf-level phenology is critical for accurately simulating ecosystem-scale responses to climate change.

  6. Do competitive interactions in dry heathlands explain plant abundance patterns and species coexistence?

    DEFF Research Database (Denmark)

    Ransijn, Johannes; Damgaard, Christian; Schmidt, Inger K

    2015-01-01

    Plant community patterns in space and time may be explained by the interactions between competing plant species. The presented study investigates this in a nutrient and species poor ecosystem. The study presents a methodology for inferring competitive interactions from yearly vegetation inventories...... and uses this to assess the outcome of competitive interactions and to predict community patterns and dynamics in a Northwest-European dry heathland. Inferred competitive interactions from five consecutive years of measurements in permanent vegetation frames at a single dry heathland site were used...... to predict the community dynamics of C. vulgaris and D. flexuosa. This was compared with the observed plant community structure at 198 Danish dry heathland sites. Interspecific competition will most likely lead to competitive exclusion of D. flexuosa at the observed temporal and spatial scale...

  7. What explains between-school differences in rates of smoking?

    Directory of Open Access Journals (Sweden)

    Wight Daniel

    2008-06-01

    Full Text Available Abstract Background Schools have the potential to influence their pupils' behaviour through the school's social organisation and culture (non-formal school characteristics, as well as through the formal curriculum. This paper examines whether these school characteristics (which include a measure of quality of social relationships can account for school differences in smoking rates. Methods This study uses a longitudinal survey involving 5,092 pupils in 24 Scottish schools. Pupils' smoking (at age 15/16, cognitive measures, attitude to school and pupils' rating of teacher pupil relationships (at age 13/14 were linked to school level data comprising teacher assessed quality of pupil-staff relationships, school level deprivation, staying on rates and attendance. Analysis involved multi-level modelling. Results Overall, 25% of males and 39% of females reported smoking, with rates by school ranging from 8% to 33% for males and from 28% to 49% for females. When individual socio-economic and socio-cultural factors were controlled for there was still a large school effect for males and a smaller (but correlated school effect for females at 15/16 years. For girls their school effect was explained by their rating of teacher-pupil relationships and attitude to school. These variables were also significant in predicting smoking among boys. However, the school effect for boys was most radically attenuated and became insignificant when the interaction between poor quality of teacher – pupil relationships and school level affluence was fitted, explaining 82% of the variance between schools. In addition, researchers' rating of the schools' focus on caring and inclusiveness was also significantly associated with both male and female smoking rates. Conclusion School-level characteristics have an impact on male and female pupils' rates of smoking up to 15/16 years of age. The size of the school effect is greater for males at this age. The social environment of

  8. Differences in energy expenditures and growth dilution explain higher PCB concentrations in male summer flounder

    Science.gov (United States)

    Madenjian, Charles P.; Jensen, Olaf P.; Rediske, Richard R.; O'Keefe, James P.; Vastano, Anthony R.; Pothoven, Steven A.

    2016-01-01

    Comparison of polychlorinated biphenyl (PCB) concentrations between the sexes of mature fish may reveal important behavioral and physiological differences between the sexes. We determined whole-fish PCB concentrations in 23 female summer flounder Paralichthys dentatus and 27 male summer flounder from New Jersey coastal waters. To investigate the potential for differences in diet or habitat utilization between the sexes, carbon and nitrogen stable isotope ratios were also determined. In 5 of the 23 female summer flounder, PCB concentrations in the somatic tissue and ovaries were determined. In addition, we used bioenergetics modeling to assess the contribution of the growth dilution effect to the observed difference in PCB concentrations between the sexes. Whole-fish PCB concentrations for females and males averaged 87 and 124 ng/g, respectively; thus males were 43% higher in PCB concentration compared with females. Carbon and nitrogen stable isotope ratios did not significantly differ between the sexes, suggesting that diet composition and habitat utilization did not vary between the sexes. Based on PCB determinations in the somatic tissue and ovaries, we predicted that PCB concentration of females would increase by 0.6%, on average, immediately after spawning due to release of eggs. Thus, the change in PCB concentration due to release of eggs did not explain the higher PCB concentrations observed in males. Bioenergetics modeling results indicated that the growth dilution effect could account for males being 19% higher in PCB concentration compared with females. Thus, the bulk of the observed difference in PCB concentrations between the sexes was not explained by growth dilution. We concluded that a higher rate of energy expenditure in males, stemming from greater activity and a greater resting metabolic rate, was most likely the primary driver for the observed difference in PCB concentrations between the sexes.

  9. Homogeneous nucleation of NAD and NAT in liquid stratospheric aerosols: insufficient to explain denitrification

    Directory of Open Access Journals (Sweden)

    D. A. Knopf

    2002-01-01

    Full Text Available The nucleation of NAD and NAT from HNO3/H2O and HNO3/H2SO4/H2O solution droplets is investigated both theoretically and experimentally with respect to the formation of polar stratospheric clouds (PSCs. Our analysis shows that homogeneous NAD and NAT nucleation from liquid aerosols is insufficient to explain the number densities of large nitric acid containing particles recently observed in the Arctic stratosphere. This conclusion is based on new droplet freezing experiments employing optical microscopy combined with Raman spectroscopy. The homogeneous nucleation rate coefficients of NAD and NAT in liquid aerosols under polar stratospheric conditions derived from the experiments are -5 cm-3 s-1 and -2 cm-3 s-1, respectively. These nucleation rate coefficients are smaller by orders of magnitude than the value of ~103 cm-3 s-1 used in a recent denitrification modelling study that is based on a linear extrapolation of laboratory nucleation data to stratospheric conditions (Tabazadeh et al., Science, 291, 2591--2594, 2001. We show that this linear extrapolation is in disagreement with thermodynamics and with experimental data and, therefore, must not be used in microphysical models of PSCs. Our analysis of the experimental data yields maximum hourly production rates of nitric acid hydrate particles per cm3 of air of about 3 x 10-10 cm-3 (air h-1 under polar stratospheric conditions. Assuming PSC particle production to proceed at this rate for two months we arrive at particle number densities of -7 cm-3, much smaller than the value of ~10-4 cm-3 reported in recent field observations. In addition, the nitric acid hydrate production rate inferred from our data is much smaller than that required to reproduce the observed denitrification in the modelling study mentioned above. This clearly shows that homogeneous nucleation of NAD and NAT from liquid supercooled ternary solution aerosols cannot explain the observed polar denitrification.

  10. Differences in Energy Expenditures and Growth Dilution Explain Higher PCB Concentrations in Male Summer Flounder.

    Directory of Open Access Journals (Sweden)

    Charles P Madenjian

    Full Text Available Comparison of polychlorinated biphenyl (PCB concentrations between the sexes of mature fish may reveal important behavioral and physiological differences between the sexes. We determined whole-fish PCB concentrations in 23 female summer flounder Paralichthys dentatus and 27 male summer flounder from New Jersey coastal waters. To investigate the potential for differences in diet or habitat utilization between the sexes, carbon and nitrogen stable isotope ratios were also determined. In 5 of the 23 female summer flounder, PCB concentrations in the somatic tissue and ovaries were determined. In addition, we used bioenergetics modeling to assess the contribution of the growth dilution effect to the observed difference in PCB concentrations between the sexes. Whole-fish PCB concentrations for females and males averaged 87 and 124 ng/g, respectively; thus males were 43% higher in PCB concentration compared with females. Carbon and nitrogen stable isotope ratios did not significantly differ between the sexes, suggesting that diet composition and habitat utilization did not vary between the sexes. Based on PCB determinations in the somatic tissue and ovaries, we predicted that PCB concentration of females would increase by 0.6%, on average, immediately after spawning due to release of eggs. Thus, the change in PCB concentration due to release of eggs did not explain the higher PCB concentrations observed in males. Bioenergetics modeling results indicated that the growth dilution effect could account for males being 19% higher in PCB concentration compared with females. Thus, the bulk of the observed difference in PCB concentrations between the sexes was not explained by growth dilution. We concluded that a higher rate of energy expenditure in males, stemming from greater activity and a greater resting metabolic rate, was most likely the primary driver for the observed difference in PCB concentrations between the sexes.

  11. [Explaining symptoms: body-object and body-subject].

    Science.gov (United States)

    ter, Meulen B C; Van Woerkom, T C A M

    2009-01-01

    Medically unexplained somatic symptoms present a real challenge to modem medicine. They occur frequently and are often chronic. To discuss the physician's approach to these symptoms. We focus on the views of the human body put forward by the French philosopher Merleau-Ponty. His view is illustrated with the help of a case study concerning a patient suffering from borderline personality disorder and complex regional pain syndrome. Merleau-Ponty draws a distinction between body-subject and body-object. By body-object he means the body as determined and predicted by medical science. By body-subject he means the body as we experience it, even before we are aware of it. It is our pre-reflexive body that gives meaning to the world around us. We argue that the physician should regard the body not only as an object, but also as a subject, thereby giving renewed attention to the significance of symptoms as an expression of inner experience. In this way symptoms that cannot be explained on a purely physico-chemical level will become more meaningful.

  12. THE ROLE OF BEHAVIORAL ECONOMICS IN EXPLAINING CONSUMPTION DECISION

    Directory of Open Access Journals (Sweden)

    Mihaela Andreea STROE

    2015-07-01

    Full Text Available The new economic approach starts from the idea that the individual does not need food, but feels the need to feed, or do not require newspapers, but feels the need of information. In this way, those who changes are not human preferences, but the way we satisfy them. At this stage of the paper, we explain the inconsistency in consumer preferences and the exceptions to the standard theory by making light upon what is called in behavioral economics: the effects of property, loss aversion and framing effects. In which concerns the standard economic model, it seems that there are discrepancies between objective measures of sources of comfort / discomfort and measures reported subjective sensations. Many defenders of classical model would argue that the measures are not reported subjective feelings of economic phenomena and therefore are not of interest to economists. However, when such feelings and sensations affect or may affect future decisions, things become relevant for the economy. Limited Rationality implies both that the agent is imperfectly informed decision-making in a complex and dynamic environment, and a limited ability processing.

  13. Four loci explain 83% of size variation in the horse.

    Directory of Open Access Journals (Sweden)

    Shokouh Makvandi-Nejad

    Full Text Available Horse body size varies greatly due to intense selection within each breed. American Miniatures are less than one meter tall at the withers while Shires and Percherons can exceed two meters. The genetic basis for this variation is not known. We hypothesize that the breed population structure of the horse should simplify efforts to identify genes controlling size. In support of this, here we show with genome-wide association scans (GWAS that genetic variation at just four loci can explain the great majority of horse size variation. Unlike humans, which are naturally reproducing and possess many genetic variants with weak effects on size, we show that horses, like other domestic mammals, carry just a small number of size loci with alleles of large effect. Furthermore, three of our horse size loci contain the LCORL, HMGA2 and ZFAT genes that have previously been found to control human height. The LCORL/NCAPG locus is also implicated in cattle growth and HMGA2 is associated with dog size. Extreme size diversification is a hallmark of domestication. Our results in the horse, complemented by the prior work in cattle and dog, serve to pinpoint those very few genes that have played major roles in the rapid evolution of size during domestication.

  14. 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.).

  15. Fatal attraction: Explaining Russia's sensitive nuclear transfers to Iran

    Science.gov (United States)

    Kuchinsky, Leah R.

    This paper explores Russia's sensitive nuclear assistance to Iran in an effort to determine why a supplier state might proliferate against its own apparent security interests. The goal is to help readers understand the supply-side dynamics of nuclear proliferation. Through careful reconstruction of the historical narrative, using open source data, this study tests the plausibility of a "fatalistic calculus" explanation, identified by Stephen Sestanovich as a possible driver for Russia's behavior. According to the hypothesis, Russia has cooperated with Iran as a way both to stay in the good graces of a neighbor that is suspected of developing nuclear weapons and to win short-term influence and profits. The paper also examines the role of other factors advanced in the existing supply-side literature, such as economic motives identified by physicist and nonproliferation scholar David Albright. The findings show that bureaucratic, economic and fatalistic factors have each played a role in motivating Russia's cooperation with Iran, with their relative importance shifting over time. Fatalism begets a strategy of Russian "minimaxing," in the lexicon of Russia scholar Robert Freedman, wherein Russia attempts to minimize damage to its relationship with the U.S. while maximizing influence in Iran via nuclear cooperation. Fatalism, as actualized by minimaxing, best explains Russia's behavior after former Russian president Vladmir Putin came to power, when the bureaucratic and economic arguments become less cogent.

  16. Mechanosensitive Adhesion Explains Stepping Motility in Amoeboid Cells.

    Science.gov (United States)

    Copos, Calina A; Walcott, Sam; Del Álamo, Juan C; Bastounis, Effie; Mogilner, Alex; Guy, Robert D

    2017-06-20

    Cells employing amoeboid motility exhibit repetitive cycles of rapid expansion and contraction and apply coordinated traction forces to their environment. Although aspects of this process are well studied, it is unclear how the cell controls the coordination of cell length changes with adhesion to the surface. Here, we develop a simple model to mechanistically explain the emergence of periodic changes in length and spatiotemporal dynamics of traction forces measured in chemotaxing unicellular amoeba, Dictyostelium discoideum. In contrast to the biochemical mechanisms that have been implicated in the coordination of some cellular processes, we show that many features of amoeboid locomotion emerge from a simple mechanochemical model. The mechanism for interaction with the environment in Dictyostelium is unknown and thus, we explore different cell-environment interaction models to reveal that mechanosensitive adhesions are necessary to reproduce the spatiotemporal adhesion patterns. In this modeling framework, we find that the other motility modes, such as smooth gliding, arise naturally with variations in the physical properties of the surface. Thus, our work highlights the prominent role of biomechanics in determining the emergent features of amoeboid locomotion. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  17. Ecological specialization in fossil mammals explains Cope's rule.

    Science.gov (United States)

    Raia, P; Carotenuto, F; Passaro, F; Fulgione, D; Fortelius, M

    2012-03-01

    Cope's rule is the trend toward increasing body size in a lineage over geological time. The rule has been explained either as passive diffusion away from a small initial body size or as an active trend upheld by the ecological and evolutionary advantages that large body size confers. An explicit and phylogenetically informed analysis of body size evolution in Cenozoic mammals shows that body size increases significantly in most inclusive clades. This increase occurs through temporal substitution of incumbent species by larger-sized close relatives within the clades. These late-appearing species have smaller spatial and temporal ranges and are rarer than the incumbents they replace, traits that are typical of ecological specialists. Cope's rule, accordingly, appears to derive mainly from increasing ecological specialization and clade-level niche expansion rather than from active selection for larger size. However, overlain on a net trend toward average size increase, significant pulses in origination of large-sized species are concentrated in periods of global cooling. These pulses plausibly record direct selection for larger body size according to Bergmann's rule, which thus appears to be independent of but concomitant with Cope's.

  18. Optimization of biomass composition explains microbial growth-stoichiometry relationships

    Science.gov (United States)

    Franklin, O.; Hall, E.K.; Kaiser, C.; Battin, T.J.; Richter, A.

    2011-01-01

    Integrating microbial physiology and biomass stoichiometry opens far-reaching possibilities for linking microbial dynamics to ecosystem processes. For example, the growth-rate hypothesis (GRH) predicts positive correlations among growth rate, RNA content, and biomass phosphorus (P) content. Such relationships have been used to infer patterns of microbial activity, resource availability, and nutrient recycling in ecosystems. However, for microorganisms it is unclear under which resource conditions the GRH applies. We developed a model to test whether the response of microbial biomass stoichiometry to variable resource stoichiometry can be explained by a trade-off among cellular components that maximizes growth. The results show mechanistically why the GRH is valid under P limitation but not under N limitation. We also show why variability of growth rate-biomass stoichiometry relationships is lower under P limitation than under N or C limitation. These theoretical results are supported by experimental data on macromolecular composition (RNA, DNA, and protein) and biomass stoichiometry from two different bacteria. In addition, compared to a model with strictly homeostatic biomass, the optimization mechanism we suggest results in increased microbial N and P mineralization during organic-matter decomposition. Therefore, this mechanism may also have important implications for our understanding of nutrient cycling in ecosystems.

  19. Deuterium enrichment of interstellar methanol explained by atom tunneling.

    Science.gov (United States)

    Goumans, T P M; Kästner, Johannes

    2011-10-06

    We calculate, down to low temperature and for different isotopes, the reaction rate constants for the hydrogen abstraction reaction H + H(3)COH → H(2) + CH(2)OH/CH(3)O. These explain the known abundances of deuterated forms of methanol in interstellar clouds, where CH(2)DOH can be almost as abundant as CH(3)OH. For abstraction from both the C- and the O-end of methanol, the barrier-crossing motion involves the movement of light hydrogen atoms. Consequently, tunneling plays a dominant role already at relatively high temperature. Our implementation of harmonic quantum transition state theory with on the fly calculation of forces and energies accounts for these tunneling effects. The results are in good agreement with previous semiclassical and quantum dynamics calculations (down to 200 K) and experimental studies (down to 295 K). Here we extend the rate calculations down to lower temperature: 30 K for abstraction from the C-end of methanol and 80 K for abstraction from the OH-group. At all temperatures, abstraction from the C-end is preferred over abstraction from the O-end, more strongly so at lower temperature. Furthermore, the tunneling behavior strongly affects the kinetic isotope effects (KIEs). D + H(3)COH → HD + CH(2)OH has a lower vibrationally adiabatic barrier than H + H(3)COH → H(2) + CH(2)OH, giving rise to an inverse KIE (k(H)/k(D) deuterium-enriched.

  20. Classifying and explaining democracy in the Muslim world

    Directory of Open Access Journals (Sweden)

    Rohaizan Baharuddin

    2012-12-01

    Full Text Available The purpose of this study is to classify and explain democracies in the 47 Muslim countries between the years 1998 and 2008 by using liberties and elections as independent variables. Specifically focusing on the context of the Muslim world, this study examines the performance of civil liberties and elections, variation of democracy practised the most, the elections, civil liberties and democratic transitions and patterns that followed. Based on the quantitative data primarily collected from Freedom House, this study demonstrates the following aggregate findings: first, the “not free not fair” elections, the “limited” civil liberties and the “Illiberal Partial Democracy” were the dominant feature of elections, civil liberties and democracy practised in the Muslim world; second, a total of 413 Muslim regimes out of 470 (47 regimes x 10 years remained the same as their democratic origin points, without any transitions to a better or worse level of democracy, throughout these 10 years; and third, a slow, yet steady positive transition of both elections and civil liberties occurred in the Muslim world with changes in the nature of elections becoming much more progressive compared to the civil liberties’ transitions.

  1. Modeling as an Anchoring Scientific Practice for Explaining Friction Phenomena

    Science.gov (United States)

    Neilson, Drew; Campbell, Todd

    2017-12-01

    Through examining the day-to-day work of scientists, researchers in science studies have revealed how models are a central sense-making practice of scientists as they construct and critique explanations about how the universe works. Additionally, they allow predictions to be made using the tenets of the model. Given this, alongside research suggesting that engaging students in developing and using models can have a positive effect on learning in science classrooms, the recent national standards documents in science education have identified developing and using models as an important practice students should engage in as they apply and refine their ideas with peers and teachers in explaining phenomena or solving problems in classrooms. This article details how students can be engaged in developing and using models to help them make sense of friction phenomena in a high school conceptual physics classroom in ways that align with visions for teaching and learning outlined in the Next Generation Science Standards. This particular unit has been refined over several years to build on what was initially an inquiry-based unit we have described previously. In this latest iteration of the friction unit, students developed and refined models through engaging in small group and whole class discussions and investigations.

  2. Explaining Russia’s Relationship with the Arctic Council

    Directory of Open Access Journals (Sweden)

    Andrew Chater

    2016-12-01

    Full Text Available Relations between the West and Russia have worsened since Russia annexed Crimea in February 2014. This article explains how this deterioration has affected the Arctic Council. The council is an international institution with eight member states with territory in the Arctic (Canada, Denmark, Finland, Iceland, Norway, Russia, Sweden and the United States as well as six indigenous peoples’ organizations. The mandate of the institution is to promote environmental protection and sustainable development in the Arctic. There is currently a debate in the media about the impact of Russia’s actions on Arctic governance. Some accounts argue that the Arctic Council’s work continues unabated in the aftermath of Crimea, while others point to worrying signs that the institution is experiencing difficulty. This research helps settle this debate by empirically demonstrating Russia’s behaviour. It concludes that the breakdown in Russian-United States relations has not had an immediate impact on the council. The article employs descriptive statistics to understand Russia’s patterns of activity in the council in three periods (1998–2000, 2007–2009 and 2013–2015. It examines Russia’s participation in meetings and its sponsorship of initiatives. It draws from a variety of council documents. It shows that earlier in the history of the council, Russia’s participation was similar to the Nordic countries. The article empirically demonstrates that Russia’s participation in the Arctic Council has increased over time.

  3. Minimal Coleman-Weinberg theory explains the diphoton excess

    DEFF Research Database (Denmark)

    Antipin, Oleg; Mojaza, Matin; Sannino, Francesco

    2016-01-01

    the introduction of an extra singlet scalar further coupled to new fermions. In this constrained setup the Higgs mass was close to the observed value and the new scalar mass was below a TeV scale. Here we first extend the previous analysis by taking into account the important difference between running mass...... and pole mass of the scalar states. We then investigate whether these theories can account for the 750 GeV excess in diphotons observed by the LHC collaborations. New QCD-colored fermions in the TeV mass range coupled to the new scalar state are needed to describe the excess. We further show, by explicit...

  4. Explaining contributions to public goods : Formalizing the social exchange heuristic

    NARCIS (Netherlands)

    Dijkstra, J.

    The public good game is a popular model of cooperation problems. Rational egoism predicts that in finitely repeated public good games no contributions are made. At least 4 observations are inconsistent with this prediction: contributions (i) are frequently positive, (ii) increase in the marginal

  5. Can dark matter explain the braking index of neutron stars?

    DEFF Research Database (Denmark)

    Kouvaris, C.; Perez-Garcia, M. A.

    2014-01-01

    We explore a new mechanism of slowing down the rotation of neutron stars via accretion of millicharged dark matter. We find that this mechanism yields pulsar braking indices that can be substantially smaller than the standard n similar to 3 of the magnetic dipole radiation model for millicharged...... dark matter particles that are not excluded by existing experimental constraints thus accommodating existing observations....

  6. Paleoclassical transport explains electron transport barriers in RTP and TEXTOR

    NARCIS (Netherlands)

    Hogeweij, G. M. D.; Callen, J.D.

    2008-01-01

    The recently developed paleoclassical transport model sets the minimum level of electron thermal transport in a tokamak. This transport level has proven to be in good agreement with experimental observations in many cases when fluctuation-induced anomalous transport is small, i.e. in (near-) ohmic

  7. Measuring and explaining competition in the financial sector

    NARCIS (Netherlands)

    Bikker, J.A.; Spierdijk, L.

    The first part of this paper provides a systematic discussion of the structural problems of competition on financial markets as observed from the demand and from the supply side, using a diagnostic framework. Potential impediments to competition are concentration, entry barriers, lack of

  8. Hyperboles not turning to metaphors : How to explain audience cooperativeness?

    NARCIS (Netherlands)

    van den Hoven, P.J.|info:eu-repo/dai/nl/070378096

    2016-01-01

    We observe that an audience attempts to interpret the relation between a source domain and a target domain as a hyperbole before interpreting it as a metaphor. It could also first try a metaphorical reading or attempt several possible readings and successively select the relevant outcome. But it

  9. Public Infrastructure in China : Explaining Growth and Spatial Inequality

    NARCIS (Netherlands)

    Yu, N.

    2016-01-01

    Public infrastructure is often mentioned as a key to promoting economic growth and development. This belief has been supported by the observation of rich countries, such as the U.S., Japan and those in Western Europe, where plenty of infrastructures developed during times of rapid economic growth.

  10. Can we explain gait changes in rheumatoid arthritis

    NARCIS (Netherlands)

    Baan, H.

    2011-01-01

    The main theme of this thesis is foot and ankle complaints in patients with RA. This choice results from the practical observations that often as clinical routine, the disease activity is determined by means of computing a DAS 28. That means that the feet and or ankles don’t have to be examined

  11. Hypotheses to explain the origin of species in Amazonia

    Directory of Open Access Journals (Sweden)

    J. Haffer

    Full Text Available The main hypotheses proposed to explain barrier formation separating populations and causing the differentiation of species in Amazonia during the course of geological history are based on different factors, as follow: (1 Changes in the distribution of land and sea or in the landscape due to tectonic movements or sea level fluctuations (Paleogeography hypothesis, (2 the barrier effect of Amazonian rivers (River hypothesis, (3 a combination of the barrier effect of broad rivers and vegetational changes in northern and southern Amazonia (River-refuge hypothesis, (4 the isolation of humid rainforest blocks near areas of surface relief in the periphery of Amazonia separated by dry forests, savannas and other intermediate vegetation types during dry climatic periods of the Tertiary and Quaternary (Refuge hypothesis, (5 changes in canopy-density due to climatic reversals (Canopy-density hypothesis (6 the isolation and speciation of animal populations in small montane habitat pockets around Amazonia due to climatic fluctuations without major vegetational changes (Museum hypothesis, (7 competitive species interactions and local species isolations in peripheral regions of Amazonia due to invasion and counterinvasion during cold/warm periods of the Pleistocene (Disturbance-vicariance hypothesis and (8 parapatric speciation across steep environmental gradients without separation of the respective populations (Gradient hypothesis. Several of these hypotheses probably are relevant to a different degree for the speciation processes in different faunal groups or during different geological periods. The basic paleogeography model refers mainly to faunal differentiation during the Tertiary and in combination with the Refuge hypothesis. Milankovitch‡ cycles leading to global main hypotheses proposed to explain barrier formation separating populations and causing the differentiation of species in Amazonia during the course of geological history are based on

  12. THE CONTEMPORARY METHODOLOGICAL APPROACHES AND THEORIES EXPLAINING INTERNATIONAL TOURISM FLOWS

    Directory of Open Access Journals (Sweden)

    Zorina SISCAN

    2017-08-01

    Full Text Available Proceeding from the fact that international tourism is in permanent growth the last decades, and contributes signi­ficantly to the development of contemporary national economies, the authors of the article have focused on methodo­logical and theoretical frame that allows deeper understanding of the touristic flows from various aspects. In doing so, the first author has launched some methodological approaches that allow deepening a perspective research on touristic flows while the second author has concentrated upon grouping and analysis of existing theories used to explain touristic flows. As an outcome, the authors recommend a blend of those approaches and theories to be used for an adequate understanding and managing the existing and perspective touristic flows.ABORDDĂRI METODOLOGICE ȘI TEORII CONTEMPORANE CARE EXPLICĂ FLUXURILE DE TURISM INTERNAȚIONALPornind de la faptul că turismul internațional manifestă permanentă creștere în ultimele decenii, precum și contribuie semnificativ la dezvoltarea economiilor naționale contemporane, autorii articolului s-au axat pe cadrul metodologic și teoretic ce ar permite conceperea aprofundată a fluxurilor de turism internațional. Primul autor a lansat unele abordări metodologice care ar contribui la aprofundarea cercetărilor de perspectivă ale fluxurilor turistice, iar cel de-al doilea autor și-a concentrat atenția asupra grupării și analizei teoriilor existente în care se explică natura fluxurilor de turism. Ca rezultat, autorii recomandă utilizarea îmbinării organice a abordărilor și teoriilor considerate pentru perceperea și gestionarea adecvată a fluxurilor de turism existente și de perspectivă.

  13. Explaining the imperfection of the molecular clock of hominid mitochondria.

    Directory of Open Access Journals (Sweden)

    Eva-Liis Loogväli

    Full Text Available The molecular clock of mitochondrial DNA has been extensively used to date various genetic events. However, its substitution rate among humans appears to be higher than rates inferred from human-chimpanzee comparisons, limiting the potential of interspecies clock calibrations for intraspecific dating. It is not well understood how and why the substitution rate accelerates. We have analyzed a phylogenetic tree of 3057 publicly available human mitochondrial DNA coding region sequences for changes in the ratios of mutations belonging to different functional classes. The proportion of non-synonymous and RNA genes substitutions has reduced over hundreds of thousands of years. The highest mutation ratios corresponding to fast acceleration in the apparent substitution rate of the coding sequence have occurred after the end of the Last Ice Age. We recalibrate the molecular clock of human mtDNA as 7990 years per synonymous mutation over the mitochondrial genome. However, the distribution of substitutions at synonymous sites in human data significantly departs from a model assuming a single rate parameter and implies at least 3 different subclasses of sites. Neutral model with 3 synonymous substitution rates can explain most, if not all, of the apparent molecular clock difference between the intra- and interspecies levels. Our findings imply the sluggishness of purifying selection in removing the slightly deleterious mutations from the human as well as the Neandertal and chimpanzee populations. However, for humans, the weakness of purifying selection has been further exacerbated by the population expansions associated with the out-of Africa migration and the end of the Last Ice Age.

  14. An experimental approach to explain the southern Andes elevational treeline.

    Science.gov (United States)

    Fajardo, Alex; Piper, Frida I

    2014-05-01

    • The growth limitation hypothesis (GLH) is the most accepted mechanistic explanation for treeline formation, although it is still uncertain whether it applies across taxa. The successful establishment of Pinus contorta--an exotic conifer species in the southern hemisphere--above the Nothofagus treeline in New Zealand may suggest a different mechanism. We tested the GLH in Nothofagus pumilio and Pinus contorta by comparing seedling performance and carbon (C) balance in response to low temperatures.• At a southern Chilean treeline, we grew seedlings of both species 2 m above ground level, to simulate coupling between temperatures at the meristem and in the air (colder), and at ground level, i.e., decoupling air temperature (relatively milder). We recorded soil and air temperatures as well. After 3 yr, we measured seedling survival and biomass (as a surrogate of growth) and determined nonstructural carbohydrates (NSC).• Nothofagus and Pinus did not differ in survival, which, as a whole, was higher at ground level than at the 2-m height. The root-zone temperature for the growing season was 6.6°C. While biomass and NSC decreased significantly for Nothofagus at the 2-m height compared with ground level (C limitation), these trends were not significant for Pinus• The treeline for Nothofagus pumilio is located at an isotherm that fully matches global patterns; however, its physiological responses to low temperatures differed from those of other treeline species. Support for C limitation in N. pumilio but not in P. contorta indicates that the physiological mechanism explaining their survival and growth at treeline may be taxon-dependent. © 2014 Botanical Society of America, Inc.

  15. Dehydration of chlorite explains anomalously high electrical conductivity in the mantle wedges.

    Science.gov (United States)

    Manthilake, Geeth; Bolfan-Casanova, Nathalie; Novella, Davide; Mookherjee, Mainak; Andrault, Denis

    2016-05-01

    Mantle wedge regions in subduction zone settings show anomalously high electrical conductivity (~1 S/m) that has often been attributed to the presence of aqueous fluids released by slab dehydration. Laboratory-based measurements of the electrical conductivity of hydrous phases and aqueous fluids are significantly lower and cannot readily explain the geophysically observed anomalously high electrical conductivity. The released aqueous fluid also rehydrates the mantle wedge and stabilizes a suite of hydrous phases, including serpentine and chlorite. In this present study, we have measured the electrical conductivity of a natural chlorite at pressures and temperatures relevant for the subduction zone setting. In our experiment, we observe two distinct conductivity enhancements when chlorite is heated to temperatures beyond its thermodynamic stability field. The initial increase in electrical conductivity to ~3 × 10(-3) S/m can be attributed to chlorite dehydration and the release of aqueous fluids. This is followed by a unique, subsequent enhancement of electrical conductivity of up to 7 × 10(-1) S/m. This is related to the growth of an interconnected network of a highly conductive and chemically impure magnetite mineral phase. Thus, the dehydration of chlorite and associated processes are likely to be crucial in explaining the anomalously high electrical conductivity observed in mantle wedges. Chlorite dehydration in the mantle wedge provides an additional source of aqueous fluid above the slab and could also be responsible for the fixed depth (120 ± 40 km) of melting at the top of the subducting slab beneath the subduction-related volcanic arc front.

  16. Microbial Diversity Indexes Can Explain Soil Carbon Dynamics as a Function of Carbon Source.

    Science.gov (United States)

    Louis, Benjamin P; Maron, Pierre-Alain; Menasseri-Aubry, Safya; Sarr, Amadou; Lévêque, Jean; Mathieu, Olivier; Jolivet, Claudy; Leterme, Philippe; Viaud, Valérie

    2016-01-01

    Mathematical models do not explicitly represent the influence of soil microbial diversity on soil organic carbon (SOC) dynamics despite recent evidence of relationships between them. The objective of the present study was to statistically investigate relationships between bacterial and fungal diversity indexes (richness, evenness, Shannon index, inverse Simpson index) and decomposition of different pools of soil organic carbon by measuring dynamics of CO2 emissions under controlled conditions. To this end, 20 soils from two different land uses (cropland and grassland) were incubated with or without incorporation of 13C-labelled wheat-straw residue. 13C-labelling allowed us to study residue mineralisation, basal respiration and the priming effect independently. An innovative data-mining approach was applied, based on generalized additive models and a predictive criterion. Results showed that microbial diversity indexes can be good covariates to integrate in SOC dynamics models, depending on the C source and the processes considered (native soil organic carbon vs. fresh wheat residue). Specifically, microbial diversity indexes were good candidates to help explain mineralisation of native soil organic carbon, while priming effect processes seemed to be explained much more by microbial composition, and no microbial diversity indexes were found associated with residue mineralisation. Investigation of relationships between diversity and mineralisation showed that higher diversity, as measured by the microbial diversity indexes, seemed to be related to decreased CO2 emissions in the control soil. We suggest that this relationship can be explained by an increase in carbon yield assimilation as microbial diversity increases. Thus, the parameter for carbon yield assimilation in mathematical models could be calculated as a function of microbial diversity indexes. Nonetheless, given limitations of the methods used, these observations should be considered with caution and

  17. What explains Rwanda's drop in fertility between 2005 and 2010 ?

    OpenAIRE

    Bundervoet, Tom

    2014-01-01

    Following a decade-and-a-half stall, fertility in Rwanda dropped sharply between 2005 and 2010. Using a hierarchical age-period-cohort model, this paper finds that the drop in fertility is largely driven by cohort effects, with younger cohorts having substantially fewer children than older cohorts observed at the same age. An Oaxaca-Blinder decomposition is applied on two successive rounds...

  18. Mesoscale symmetries explain dynamical equivalence of food webs

    OpenAIRE

    Aufderheide, Helge; Rudolf, Lars; Gross, Thilo

    2012-01-01

    A present challenge in complex systems is to identify mesoscale structures that have distinct dynamical implications. In this paper we present a detailed investigation of a previously observed dynamical equivalence of certian ecological food webs. We show that this equivalence is rooted in mesoscale symmetries that exist in these webs. Certain eigenvectors of the Jacobian describing dynamical modes of the system, such as specific instabilities or responses to perturbations, localize on these ...

  19. Can the Emdrive Be Explained by Quantised Inertia?

    Directory of Open Access Journals (Sweden)

    McCulloch M. E.

    2015-01-01

    Full Text Available It has been shown that cone-shaped cavities with microwaves resonating within them move slightly towards their narrow ends (the emdrive. There is no accepted explanation for this. Here it is shown that this effect can be predicted by assuming that the inertial mass of the photons in the cavity is caused by Unruh radiation whose wavelengths must fit exactly within the cavity, using a theory already applied with some success to astrophysical anomalies where the cavity is the Hubble volume. For the emdrive this means that more Unruh waves are “allowed” at the wide end, lea ding to a greater inertial mass for the photons there. The gain of inertia of the photons when they move from the narrow to the wide end, and the conservation of momentum, predicts that the cavity must then move towards the narrow end, as observed. This mode l predicts the available observations quite well, although the observational uncertainties are not well known.

  20. Dense neuron clustering explains connectivity statistics in cortical microcircuits.

    Directory of Open Access Journals (Sweden)

    Vladimir V Klinshov

    Full Text Available Local cortical circuits appear highly non-random, but the underlying connectivity rule remains elusive. Here, we analyze experimental data observed in layer 5 of rat neocortex and suggest a model for connectivity from which emerge essential observed non-random features of both wiring and weighting. These features include lognormal distributions of synaptic connection strength, anatomical clustering, and strong correlations between clustering and connection strength. Our model predicts that cortical microcircuits contain large groups of densely connected neurons which we call clusters. We show that such a cluster contains about one fifth of all excitatory neurons of a circuit which are very densely connected with stronger than average synapses. We demonstrate that such clustering plays an important role in the network dynamics, namely, it creates bistable neural spiking in small cortical circuits. Furthermore, introducing local clustering in large-scale networks leads to the emergence of various patterns of persistent local activity in an ongoing network activity. Thus, our results may bridge a gap between anatomical structure and persistent activity observed during working memory and other cognitive processes.

  1. Possible mechanism for explaining the origin and size distribution of Martian hematite spherules

    Science.gov (United States)

    Misra, Anupam K.; Acosta-Maeda, Tayro E.; Scott, Edward R. D.; Sharma, Shiv K.

    2014-03-01

    Mysterious hematite spherules, also known as “blueberries”, observed at Meridiani Planum on Mars have been widely accepted as concretions which are formed by precipitation of aqueous fluids. One of the biggest mysteries is that all observed Martian blueberries are limited in size with maximum diameter of 6.2 mm. In contrast, terrestrial concretions are not size limited. In this article, we discuss significant differences between Martian blueberries and Earth concretion analogs. Puzzling observations from Mars Exploration Rovers Opportunity and Spirit suggest that the spherules may not be concretions but are cosmic spherules formed by ablation of meteorites. The perfect spherical shape of spherules, their observed size limit, and all other physical properties are easily explained by a meteorite ablation model. Evidence that some of these spherules are only few years old strongly constrains concretion and other growth mechanisms related to aqueous processes that require the existence of water on Mars in its recent history. The large number of hematite spherules in Meridiani Planum may be due to a big rare iron meteorite impact event in this region sometime in the past.

  2. Force loading explains spatial sensing of ligands by cells

    Science.gov (United States)

    Oria, Roger; Wiegand, Tina; Escribano, Jorge; Elosegui-Artola, Alberto; Uriarte, Juan Jose; Moreno-Pulido, Cristian; Platzman, Ilia; Delcanale, Pietro; Albertazzi, Lorenzo; Navajas, Daniel; Trepat, Xavier; García-Aznar, José Manuel; Cavalcanti-Adam, Elisabetta Ada; Roca-Cusachs, Pere

    2017-12-01

    Cells can sense the density and distribution of extracellular matrix (ECM) molecules by means of individual integrin proteins and larger, integrin-containing adhesion complexes within the cell membrane. This spatial sensing drives cellular activity in a variety of normal and pathological contexts. Previous studies of cells on rigid glass surfaces have shown that spatial sensing of ECM ligands takes place at the nanometre scale, with integrin clustering and subsequent formation of focal adhesions impaired when single integrin–ligand bonds are separated by more than a few tens of nanometres. It has thus been suggested that a crosslinking ‘adaptor’ protein of this size might connect integrins to the actin cytoskeleton, acting as a molecular ruler that senses ligand spacing directly. Here, we develop gels whose rigidity and nanometre-scale distribution of ECM ligands can be controlled and altered. We find that increasing the spacing between ligands promotes the growth of focal adhesions on low-rigidity substrates, but leads to adhesion collapse on more-rigid substrates. Furthermore, disordering the ligand distribution drastically increases adhesion growth, but reduces the rigidity threshold for adhesion collapse. The growth and collapse of focal adhesions are mirrored by, respectively, the nuclear or cytosolic localization of the transcriptional regulator protein YAP. We explain these findings not through direct sensing of ligand spacing, but by using an expanded computational molecular-clutch model, in which individual integrin–ECM bonds—the molecular clutches—respond to force loading by recruiting extra integrins, up to a maximum value. This generates more clutches, redistributing the overall force among them, and reducing the force loading per clutch. At high rigidity and high ligand spacing, maximum recruitment is reached, preventing further force redistribution and leading to adhesion collapse. Measurements of cellular traction forces and actin flow

  3. Fifteen Years of Explaining Pain: The Past, Present, and Future.

    Science.gov (United States)

    Moseley, G Lorimer; Butler, David S

    2015-09-01

    The pain field has been advocating for some time for the importance of teaching people how to live well with pain. Perhaps some, and maybe even for many, we might again consider the possibility that we can help people live well without pain. Explaining Pain (EP) refers to a range of educational interventions that aim to change one's understanding of the biological processes that are thought to underpin pain as a mechanism to reduce pain itself. It draws on educational psychology, in particular conceptual change strategies, to help patients understand current thought in pain biology. The core objective of the EP approach to treatment is to shift one's conceptualization of pain from that of a marker of tissue damage or disease to that of a marker of the perceived need to protect body tissue. Here, we describe the historical context and beginnings of EP, suggesting that it is a pragmatic application of the biopsychosocial model of pain, but differentiating it from cognitive behavioral therapy and educational components of early multidisciplinary pain management programs. We attempt to address common misconceptions of EP that have emerged over the last 15 years, highlighting that EP is not behavioral or cognitive advice, nor does it deny the potential contribution of peripheral nociceptive signals to pain. We contend that EP is grounded in strong theoretical frameworks, that its targeted effects are biologically plausible, and that available behavioral evidence is supportive. We update available meta-analyses with results of a systematic review of recent contributions to the field and propose future directions by which we might enhance the effects of EP as part of multimodal pain rehabilitation. Perspective: EP is a range of educational interventions. EP is grounded in conceptual change and instructional design theory. It increases knowledge of pain-related biology, decreases catastrophizing, and imparts short-term reductions in pain and disability. It presents the

  4. Fitness trade-offs explain low levels of persister cells in the opportunistic pathogen Pseudomonas aeruginosa.

    Science.gov (United States)

    Stepanyan, Kristine; Wenseleers, Tom; Duéñez-Guzmán, Edgar A; Muratori, Frédéric; Van den Bergh, Bram; Verstraeten, Natalie; De Meester, Luc; Verstrepen, Kevin J; Fauvart, Maarten; Michiels, Jan

    2015-04-01

    Microbial populations often contain a fraction of slow-growing persister cells that withstand antibiotics and other stress factors. Current theoretical models predict that persistence levels should reflect a stable state in which the survival advantage of persisters under adverse conditions is balanced with the direct growth cost impaired under favourable growth conditions, caused by the nonreplication of persister cells. Based on this direct growth cost alone, however, it remains challenging to explain the observed low levels of persistence (human pathogen Pseudomonas aeruginosa that can explain this discrepancy by revealing various previously unknown costs of persistence. In particular, we show that in the absence of antibiotic stress, increased persistence is traded off against a lengthened lag phase as well as a reduced survival ability during stationary phase. We argue that these pleiotropic costs contribute to the very low proportions of persister cells observed among natural P. aeruginosa isolates (3 × 10(-8) -3 × 10(-4)) and that they can explain why strains with higher proportions of persister cells lose out very quickly in competition assays under favourable growth conditions, despite a negligible difference in maximal growth rate. We discuss how incorporating these trade-offs could lead to models that can better explain the evolution of persistence in nature and facilitate the rational design of alternative therapeutic strategies for treating infectious diseases. © 2015 John Wiley & Sons Ltd.

  5. Territoriality and Conflict Avoidance Explain Asociality (Solitariness of the Endosymbiotic Pea Crab Tunicotheres moseri.

    Directory of Open Access Journals (Sweden)

    Louis J Ambrosio

    Full Text Available Host monopolization theory predicts symbiotic organisms inhabiting morphologically simple, relatively small and scarce hosts to live solitarily as a result of territorial behaviors. We tested this prediction with Tunicotheres moseri, an endosymbiotic crab dwelling in the atrial chamber of the morphologically simple, small, and relatively scarce ascidian Styela plicata. As predicted, natural populations of T. moseri inhabit ascidian hosts solitarily with greater frequency than expected by chance alone. Furthermore, laboratory experiments demonstrated that intruder crabs take significantly longer to colonize previously infected compared to uninfected hosts, indicating as expected, that resident crabs exhibit monopolization behaviors. While territoriality does occur, agonistic behaviors employed by T. moseri do not mirror the overt behaviors commonly reported for other territorial crustaceans. Documented double and triple cohabitations in the field coupled with laboratory observations demonstrating the almost invariable success of intruder crabs colonizing occupied hosts, suggest that territoriality is ineffective in completely explaining the solitary social habit of this species. Additional experiments showed that T. moseri juveniles and adults, when searching for ascidians use chemical cues to avoid hosts occupied by conspecifics. This conspecific avoidance behavior reported herein is a novel strategy most likely employed to preemptively resolve costly territorial conflicts. In general, this study supports predictions central to host monopolization theory, but also implies that alternative behavioral strategies (i.e., conflict avoidance may be more important than originally thought in explaining the host use pattern of symbiotic organisms.

  6. Does individualism help explain differences in employers' stigmatizing attitudes toward disability across Chinese and American cities?

    Science.gov (United States)

    Rao, Deepa; Horton, Randall A; Tsang, Hector W H; Shi, Kan; Corrigan, Patrick W

    2010-11-01

    Stigmatizing attitudes toward people with disabilities can jeopardize such individuals' well-being and recovery through denial of employment and community isolation. By shaping social norms that define group membership, the construct of individualism may partially explain differences in stigmatizing attitudes across cultures. Further, widespread globalization has brought intensely individualistic social practices to certain segments of non-Western cultures. This paper examines whether the construct of individualism can help to explain cross-cultural differences in stigmatizing attitudes observed between American and Chinese employers. Employers (N = 879) from Beijing, Hong Kong, and Chicago provided information on their attitudes toward hiring people with disabilities, and path analyses were conducted to examine potential mediating relationships. Path analyses indicated that vertical individualism, along with perceived responsibility for acquiring a condition, partially mediated the relationship between culture and employers' negative attitudes about job candidates with disabilities. These results suggested that greater espousal of competitive and individualist values may drive stigmatizing attitudes across cultures. (PsycINFO Database Record (c) 2010 APA, all rights reserved).

  7. The Growth of Older Inmate Populations: How Population Aging Explains Rising Age at Admission.

    Science.gov (United States)

    Luallen, Jeremy; Cutler, Christopher

    2017-09-01

    Older inmates are the fastest growing segment of the prison population; however, the reasons for this are not well understood. One explanation is that the general population is aging, driving prison age distributions to change. For this article, we study the role of population aging in prison growth by investigating how the baby boom phenomenon of post-World War II has contributed to the growth of older inmate populations. We identify the impact of population aging using simulation methods that explain prison growth as the combination of criminal justice processes. Overall, we find evidence that population aging has played a significant role in explaining the growth of older inmate populations, in particular among inmates aged between 50 and 64 years, contributing to as much as half of the observed increase in these groups since 2000. This finding stands in contrast to the notion that population aging has little explanatory power in describing the growth of prison populations and implies that older inmate groups are more sensitive to compositional changes in the general population. We argue that prediction-based modeling of prison growth should more seriously consider the impacts and consequences of demographic shifts among older prisoner populations.

  8. The extracellular microenvironment explains variations in passive drug transport across different airway epithelial cell types.

    Science.gov (United States)

    Min, Kyoung Ah; Talattof, Arjang; Tsume, Yasuhiro; Stringer, Kathleen A; Yu, Jing-Yu; Lim, Dong Hyun; Rosania, Gus R

    2013-08-01

    We sought to identify key variables in cellular architecture and physiology that might explain observed differences in the passive transport properties of small molecule drugs across different airway epithelial cell types. Propranolol (PR) was selected as a weakly basic, model compound to compare the transport properties of primary (NHBE) vs. tumor-derived (Calu-3) cells. Differentiated on Transwell™ inserts, the architecture of pure vs. mixed cell co-cultures was studied with confocal microscopy followed by quantitative morphometric analysis. Cellular pharmacokinetic modeling was used to identify parameters that differentially affect PR uptake and transport across these two cell types. Pure Calu-3 and NHBE cells possessed different structural and functional properties. Nevertheless, mixed Calu-3 and NHBE cell co-cultures differentiated as stable cell monolayers. After measuring the total mass of PR, the fractional areas covered by Calu-3 and NHBE cells allowed deconvoluting the transport properties of each cell type. Based on the apparent thickness of the unstirred, cell surface aqueous layer, local differences in the extracellular microenvironment explained the measured variations in passive PR uptake and permeation between Calu-3 and NHBE cells. Mixed cell co-cultures can be used to compare the local effects of the extracellular microenvironment on drug uptake and transport across two epithelial cell types.

  9. Newly recognized turbidity current structure can explain prolonged flushing of submarine canyons.

    Science.gov (United States)

    Azpiroz-Zabala, Maria; Cartigny, Matthieu J B; Talling, Peter J; Parsons, Daniel R; Sumner, Esther J; Clare, Michael A; Simmons, Stephen M; Cooper, Cortis; Pope, Ed L

    2017-10-01

    Seabed-hugging flows called turbidity currents are the volumetrically most important process transporting sediment across our planet and form its largest sediment accumulations. We seek to understand the internal structure and behavior of turbidity currents by reanalyzing the most detailed direct measurements yet of velocities and densities within oceanic turbidity currents, obtained from weeklong flows in the Congo Canyon. We provide a new model for turbidity current structure that can explain why these are far more prolonged than all previously monitored oceanic turbidity currents, which lasted for only hours or minutes at other locations. The observed Congo Canyon flows consist of a short-lived zone of fast and dense fluid at their front, which outruns the slower moving body of the flow. We propose that the sustained duration of these turbidity currents results from flow stretching and that this stretching is characteristic of mud-rich turbidity current systems. The lack of stretching in previously monitored flows is attributed to coarser sediment that settles out from the body more rapidly. These prolonged seafloor flows rival the discharge of the Congo River and carry ~2% of the terrestrial organic carbon buried globally in the oceans each year through a single submarine canyon. Thus, this new structure explains sustained flushing of globally important amounts of sediment, organic carbon, nutrients, and fresh water into the deep ocean.

  10. Explaining why nurses remain in or leave bedside nursing: a critical ethnography.

    Science.gov (United States)

    Mahon, Paula; McPherson, Gladys

    2014-09-01

    To describe the application of critical ethnography to explain nurses' decisions to remain in or leave bedside nursing, and to describe researcher positioning and reflexivity. Enquiry into hospital nurses' decisions to remain in or leave bedside nursing positions has been conducted from a variety of theoretical perspectives by researchers adopting a range of methodological approaches. This research helps to explain how work environments can affect variables such as job satisfaction and turnover, but provides less insight into how personal and professional factors shape decisions to remain in or leave bedside nursing. A critical theoretical perspective was taken to examine the employment decisions made by nurses in a paediatric intensive care unit (PICU). Data was collected from nurses (n=31) through semi-structured interviews and unobtrusive observation. The authors describe critical ethnography as a powerful research framework for enquiry that allowed them to challenge assumptions about why nurses remain in or leave their jobs, and to explore how issues of fairness and equity contribute to these decisions. Critical ethnography offers a powerful methodology for investigations into complex interactions, such as those between nurses in a PICU. In adopting this methodology, researchers should be sensitised to manifestations of power, attend to their stance and location, and reflexion. The greatest challenges from this research included how to make sense of the insider position, how to acknowledge assumptions and allow these to be challenged, and how to ensure that power relationships in the environment and in the research were attended to.

  11. Can hydroseismicity explain recurring earthquake swarms in NW-Bohemia?

    Science.gov (United States)

    Heinicke, Jens; Woith, Heiko; Alexandrakis, Catherine; Buske, Stefan; Telesca, Luciano

    2018-01-01

    Fluid driven seismicity has been observed worldwide. The occurrence of intraplate seismicity triggered by pore pressure perturbations is a widely accepted process. Past analysis of earthquake swarms in the NW-Bohemia/Vogtland region provided evidence for the diffusion of pore pressure fronts during the migration of earthquakes within each swarm. Here, we test the hypothesis whether the diffusion of hydraulically induced pore pressure perturbations from the surface to the hypocentral depth could be a valid trigger mechanism. We test this hypothesis for the earthquake swarms in the Nový Kostel focal zone based on the analysis of 121 earthquake swarms and microswarms which occurred between 1992 and 2016.

  12. Human wavelength discrimination of monochromatic light explained by optimal wavelength decoding of light of unknown intensity.

    Directory of Open Access Journals (Sweden)

    Li Zhaoping

    Full Text Available We show that human ability to discriminate the wavelength of monochromatic light can be understood as maximum likelihood decoding of the cone absorptions, with a signal processing efficiency that is independent of the wavelength. This work is built on the framework of ideal observer analysis of visual discrimination used in many previous works. A distinctive aspect of our work is that we highlight a perceptual confound that observers should confuse a change in input light wavelength with a change in input intensity. Hence a simple ideal observer model which assumes that an observer has a full knowledge of input intensity should over-estimate human ability in discriminating wavelengths of two inputs of unequal intensity. This confound also makes it difficult to consistently measure human ability in wavelength discrimination by asking observers to distinguish two input colors while matching their brightness. We argue that the best experimental method for reliable measurement of discrimination thresholds is the one of Pokorny and Smith, in which observers only need to distinguish two inputs, regardless of whether they differ in hue or brightness. We mathematically formulate wavelength discrimination under this wavelength-intensity confound and show a good agreement between our theoretical prediction and the behavioral data. Our analysis explains why the discrimination threshold varies with the input wavelength, and shows how sensitively the threshold depends on the relative densities of the three types of cones in the retina (and in particular predict discriminations in dichromats. Our mathematical formulation and solution can be applied to general problems of sensory discrimination when there is a perceptual confound from other sensory feature dimensions.

  13. The evolution of fairness: explaining variation in bargaining behaviour.

    Science.gov (United States)

    Lamba, Shakti; Mace, Ruth

    2013-01-07

    Conceptions of fairness vary across the world. Identifying the drivers of this variation is key to understanding the selection pressures and mechanisms that lead to the evolution of fairness in humans. Individuals' varying fairness preferences are widely assumed to represent cultural norms. However, this assumption has not previously been tested. Fairness norms are defined as culturally transmitted equilibria at which bargainers have coordinated expectations from each other. Hence, if fairness norms exist at the level of the ethno-linguistic group, we should observe two patterns. First, cultural conformism should maintain behavioural homogeneity within an ethno-linguistic group. Second, bargainers' expectations should be coordinated such that proposals and responses to proposals should covary. Here we show that neither of these patterns is observed across 21 populations of the same ethno-linguistic group, the Pahari Korwa of central India. Our findings suggest that what constitutes a fair division of resources can vary on smaller scales than that of the ethno-linguistic group. Individuals' local environments may play a central role in determining conceptions of fairness.

  14. Fluid Mechanics Explains Cosmology, Dark Matter, Dark Energy, and Life

    CERN Document Server

    Gibson, Carl H

    2012-01-01

    Observations of the interstellar medium by the Herschel, Planck etc. infrared satellites throw doubt on standard {\\Lambda}CDMHC cosmological processes to form gravitational structures. According to the Hydro-Gravitational-Dynamics (HGD) cosmology of Gibson (1996), and the quasar microlensing observations of Schild (1996), the dark matter of galaxies consists of Proto-Globular-star-Cluster (PGC) clumps of Earth-mass primordial gas planets in metastable equilibrium since PGCs began star production at 0.3 Myr by planet mergers. Dark energy and the accelerating expansion of the universe inferred from SuperNovae Ia are systematic dimming errors produced as frozen gas dark matter planets evaporate to form stars. Collisionless cold dark matter that clumps and hierarchically clusters does not exist. Clumps of PGCs began diffusion from the Milky Way Proto-Galaxy upon freezing at 14 Myr to give the Magellanic Clouds and the faint dwarf galaxies of the 10^22 m diameter baryonic dark matter Galaxy halo. The first stars p...

  15. Reinforcement learning and counterfactual reasoning explain adaptive behavior in a changing environment.

    Science.gov (United States)

    Zhang, Yunfeng; Paik, Jaehyon; Pirolli, Peter

    2015-04-01

    Animals routinely adapt to changes in the environment in order to survive. Though reinforcement learning may play a role in such adaptation, it is not clear that it is the only mechanism involved, as it is not well suited to producing rapid, relatively immediate changes in strategies in response to environmental changes. This research proposes that counterfactual reasoning might be an additional mechanism that facilitates change detection. An experiment is conducted in which a task state changes over time and the participants had to detect the changes in order to perform well and gain monetary rewards. A cognitive model is constructed that incorporates reinforcement learning with counterfactual reasoning to help quickly adjust the utility of task strategies in response to changes. The results show that the model can accurately explain human data and that counterfactual reasoning is key to reproducing the various effects observed in this change detection paradigm. Copyright © 2015 Cognitive Science Society, Inc.

  16. Are low Danish fertility rates explained by changes in timing of births?

    DEFF Research Database (Denmark)

    Hvidtfeldt, Ulla A; Gerster, Mette; Knudsen, Lisbeth B

    2010-01-01

    AIMS: The most commonly used indicator of fertility, the period total fertility rate (TFR(p)), tends to underestimate actual fertility when women delay childbearing. The objective of this study was to examine to which extent fluctuations in Danish fertility rates result from changes in timing...... of births and, thus, whether the conventional TFR(p) is a distorted indicator of fertility quantum. In addition, we investigated whether such changes in timing explained the observed regional differences in the TFR(p) in Denmark. METHODS: The study applied age-, period-, county-, and parity-specific data...... from the Danish Fertility of Women and Couples Dataset, 1980-2001. We evaluated fluctuations in period fertility rates by the tempo-adjusted TFR(') - a proposed variant of the conventional TFR(p) taking period changes in timing of births into account. Tempo-effects were given by the difference between...

  17. The Importance of Stochastic Effects for Explaining Entrainment in the Zebrafish Circadian Clock

    Directory of Open Access Journals (Sweden)

    Raphaela Heussen

    2015-01-01

    Full Text Available The circadian clock plays a pivotal role in modulating physiological processes and has been implicated, either directly or indirectly, in a range of pathological states including cancer. Here we investigate how the circadian clock is entrained by external cues such as light. Working with zebrafish cell lines and combining light pulse experiments with simulation efforts focused on the role of synchronization effects, we find that even very modest doses of light exposure are sufficient to trigger some entrainment, whereby a higher light intensity or duration correlates with strength of the circadian signal. Moreover, we observe in the simulations that stochastic effects may be considered an essential feature of the circadian clock in order to explain the circadian signal decay in prolonged darkness, as well as light initiated resynchronization as a strong component of entrainment.

  18. Do social norms play a role in explaining involvement in medical decision-making?

    Science.gov (United States)

    Brabers, Anne E M; van Dijk, Liset; Groenewegen, Peter P; de Jong, Judith D

    2016-12-01

    Patients' involvement in medical decision-making is crucial to provide good quality of care that is respectful of, and responsive to, patients' preferences, needs and values. Whether people want to be involved in medical decision-making is associated with individual patient characteristics, and health status. However, the observation of differences in whether people want to be involved does not in itself provide an explanation. Insight is necessary into mechanisms that explain people's involvement. This study aims to examine one mechanism, namely social norms. We make a distinction between subjective norms, that is doing what others think one ought to do, and descriptive norms, doing what others do. We focus on self-reported involvement in medical decision-making. A questionnaire was sent to members of the Dutch Health Care Consumer Panel in May 2015 (response 46%; N = 974). A regression model was used to estimate the relationship between socio-demographics, social norms and involvement in medical decision-making. In line with our hypotheses, we observed that the more conservative social norms are, the less people are involved in medical decision-making. The effects for both types of norms were comparable. This study indicates that social norms play a role as a mechanism to explain involvement in medical decision-making. Our study offers a first insight into the possibility that the decision to be involved in medical decision-making is not as individual as it at first seems; someone's social context also plays a role. Strategies aimed at emphasizing patient involvement have to address this social context. © The Author 2016. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

  19. Age-independent seismic anisotropy under oceanic plates explained by strain history in the asthenosphere

    Science.gov (United States)

    Hedjazian, Navid; Garel, Fanny; Davies, D. Rhodri; Kaminski, Edouard

    2017-02-01

    The depth of the oceanic lithosphere-asthenosphere boundary (LAB), as inferred from shear wave velocities, increases with lithospheric age, in agreement with models of cooling oceanic lithosphere. On the other hand, the distribution of radial anisotropy under oceanic plates is almost age-independent. In particular, radial anisotropy shows a maximum positive gradient at a depth of ∼70 km, which, if used as a proxy, indicates an age-independent LAB depth. These contrasting observations have fueled a controversy on the seismological signature of the LAB. To better understand the discrepancy between these observations, we model the development of lattice preferred orientation (LPO) in upper mantle crystal aggregates and predict the seismic anisotropy produced by plate-driven mid-ocean ridge flows. The model accounts for the progressive cooling of the lithosphere with age and can incorporate both diffusion and dislocation creep deformation mechanisms. We find that an age-independent distribution of radial anisotropy is the natural consequence of these simple flows. The depth and strength of anisotropy is further controlled by the deformation regime - dislocation or diffusion creep - experienced by crystals during their ascent towards, and subsequent motion away from, the ridge axis. Comparison to surface wave tomography models yield constraints on rheological parameters such as the activation volume. Although not excluded, additional mechanisms proposed to explain some geophysical signatures of the LAB, such as the presence of partial melt or changes in water content, are not required to explain the radial anisotropy proxy. Our prediction, that the age-independent radial anisotropy proxy marks the transition to flow-induced asthenospheric anisotropy, provides a way to reconcile thermal, mechanical and seismological views of the LAB.

  20. Does geography explain ethnic inequalities in health in New Zealand?

    Science.gov (United States)

    Tobias, Martin; Searle, Paula

    2006-10-01

    To quantify the potential contribution of inter-district relative to intradistrict variation to the Maori disparity in life expectancy in 2000-02, by counterfactual modelling. SETTING, DATA SOURCES AND METHODS: The setting was New Zealand's 21 health districts (District Health Boards, DHBs). All data (population estimates and life expectancy estimates) were sourced from Statistics New Zealand and relate to the 2000-02 period. Maori life expectancy (nationally) was recalculated under the counterfactual that Maori life expectancy in each DHB did not differ from total population life expectancy in the corresponding DHB (so eliminating intra-district variation). The difference between the observed total population and counterfactual Maori life expectancies therefore represents the contribution of inter-district variation to the Maori life expectancy disparity. Observed total population and Maori life expectancies at birth in 2000-02, pooling sexes, were 78.7 and 71.1 years respectively, giving a total disparity of 7.6 years. Under the counterfactual, Maori life expectancy increased to 78.4 years (and total population life expectancy to 79.0 years). Inter-district variation was therefore estimated to potentially contribute only 0.6 years or 8% to the total Maori disparity. Allowing for imprecision, inter-district variation almost certainly accounts for less than 10.5% of the total disparity. Inter-district or geographic variation makes only a small contribution to the total Maori disparity in life expectancy. Adjustment or standardisation for district is not necessary when comparing Maori and non-Maori health outcomes. If the policy goal is to reduce ethnic inequalities in health, then the focus of policy (e.g. funding formulae) needs to be on factors directly linked to ethnicity, rather than on geographic variations in health and health care that have an impact on all ethnic groups more-or-less alike.

  1. Observational biases for transiting planets

    Science.gov (United States)

    Kipping, David M.; Sandford, Emily

    2016-12-01

    Observational biases distort our view of nature, such that the patterns we see within a surveyed population of interest are often unrepresentative of the truth we seek. Transiting planets currently represent the most informative data set on the ensemble properties of exoplanets within 1 au of their star. However, the transit method is inherently biased due to both geometric and detection-driven effects. In this work, we derive the overall observational biases affecting the most basic transit parameters from first principles. By assuming a trapezoidal transit and using conditional probability, we infer the expected distribution of these terms both as a joint distribution and in a marginalized form. These general analytic results provide a baseline against which to compare trends predicted by mission-tailored injection/recovery simulations and offer a simple way to correct for observational bias. Our results explain why the observed population of transiting planets displays a non-uniform impact parameter distribution, with a bias towards near-equatorial geometries. We also find that the geometric bias towards observed planets transiting near periastron is attenuated by the longer durations which occur near apoastron. Finally, we predict that the observational bias with respect to ratio-of-radii is super-quadratic, scaling as (RP/R⋆)5/2, driven by an enhanced geometric transit probability and modestly longer durations.

  2. Ancient Structure in Africa Unlikely to Explain Neanderthal and Non-African Genetic Similarity

    Science.gov (United States)

    Yang, Melinda A.; Malaspinas, Anna-Sapfo; Durand, Eric Y.; Slatkin, Montgomery

    2012-01-01

    Neanderthals have been shown to share more genetic variants with present-day non-Africans than Africans. Recent admixture between Neanderthals and modern humans outside of Africa was proposed as the most parsimonious explanation for this observation. However, the hypothesis of ancient population structure within Africa could not be ruled out as an alternative explanation. We use simulations to test whether the site frequency spectrum, conditioned on a derived Neanderthal and an ancestral Yoruba (African) nucleotide (the doubly conditioned site frequency spectrum [dcfs]), can distinguish between models that assume recent admixture or ancient population structure. We compare the simulations to the dcfs calculated from data taken from populations of European, Chinese, and Japanese descent in the Complete Genomics Diversity Panel. Simulations under a variety of plausible demographic parameters were used to examine the shape of the dcfs for both models. The observed shape of the dcfs cannot be explained by any set of parameter values used in the simulations of the ancient structure model. The dcfs simulations for the recent admixture model provide a good fit to the observed dcfs for non-Africans, thereby supporting the hypothesis that recent admixture with Neanderthals accounts for the greater similarity of Neanderthals to non-Africans than Africans. PMID:22513287

  3. Ancient structure in Africa unlikely to explain Neanderthal and non-African genetic similarity.

    Science.gov (United States)

    Yang, Melinda A; Malaspinas, Anna-Sapfo; Durand, Eric Y; Slatkin, Montgomery

    2012-10-01

    Neanderthals have been shown to share more genetic variants with present-day non-Africans than Africans. Recent admixture between Neanderthals and modern humans outside of Africa was proposed as the most parsimonious explanation for this observation. However, the hypothesis of ancient population structure within Africa could not be ruled out as an alternative explanation. We use simulations to test whether the site frequency spectrum, conditioned on a derived Neanderthal and an ancestral Yoruba (African) nucleotide (the doubly conditioned site frequency spectrum [dcfs]), can distinguish between models that assume recent admixture or ancient population structure. We compare the simulations to the dcfs calculated from data taken from populations of European, Chinese, and Japanese descent in the Complete Genomics Diversity Panel. Simulations under a variety of plausible demographic parameters were used to examine the shape of the dcfs for both models. The observed shape of the dcfs cannot be explained by any set of parameter values used in the simulations of the ancient structure model. The dcfs simulations for the recent admixture model provide a good fit to the observed dcfs for non-Africans, thereby supporting the hypothesis that recent admixture with Neanderthals accounts for the greater similarity of Neanderthals to non-Africans than Africans.

  4. Slippage of Jets Explained by the Magnetic Topology of NOAA Active Region 12035

    Science.gov (United States)

    Joshi, R.; Schmieder, B.; Chandra, R.; Aulanier, G.; Zuccarello, F. P.; Uddin, W.

    2017-10-01

    We present the investigation of 11 recurring solar jets that originated from two different sites (site 1 and site 2) close to each other (≈ 11 Mm) in NOAA active region (AR) 12035 during 15 - 16 April 2014. The jets were observed by the Atmospheric Imaging Assembly (AIA) telescope on board the Solar Dynamics Observatory (SDO) satellite. Two jets were observed by the telescope of the Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital, India, in Hα. On 15 April, flux emergence is strong in site 1, while on 16 April, flux emergence and cancellation mechanisms are involved in both sites. The jets of both sites have parallel trajectories and move to the south with a speed between 100 and 360 km s-1. The jets of site 2 occurred during the second day have a tendency to move toward the jets of site 1 and merge with them. We conjecture that the slippage of the jets could be explained by the complex topology of the region, which included a few low-altitude null points and many quasi-separatrix layers (QSLs), which could intersect with one another.

  5. Does selection bias explain the obesity paradox among individuals with cardiovascular disease?

    Science.gov (United States)

    Banack, Hailey R; Kaufman, Jay S

    2015-05-01

    The objectives of this article are to demonstrate that the obesity paradox may be explained by collider stratification bias and to estimate the biasing effects of unmeasured common causes of cardiovascular disease (CVD) and mortality on the observed obesity-mortality relationship. We use directed acyclic graphs, regression modeling, and sensitivity analyses to explore whether the observed protective effect of obesity among individuals with CVD can be plausibly attributed to selection bias. Data from the third National Health and Examination Survey was used for the analyses. The adjusted total effect of obesity on mortality was a risk difference (RD) of 0.03 (95% confidence interval [CI]: 0.02, 0.05). However, the controlled direct effect of obesity on mortality among individuals without CVD was RD = 0.03 (95% CI: 0.01, 0.05) and RD = -0.12 (95% CI: -0.20, -0.04) among individuals with CVD. The adjusted total effect estimate demonstrates an increased number of deaths among obese individuals relative to nonobese counterparts, whereas the controlled direct effect shows a paradoxical decrease in morality among obese individuals with CVD. Sensitivity analysis demonstrates unmeasured confounding of the mediator-outcome relationship provides a sufficient explanation for the observed protective effect of obesity on mortality among individuals with CVD. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Residence times in shallow waters help explain regional differences in Wadden Sea eutrophication

    Science.gov (United States)

    Schwichtenberg, Fabian; Callies, Ulrich; van Beusekom, Justus E. E.

    2017-04-01

    Regional variations in eutrophication levels of tidal basins in the Wadden Sea can be caused by external factors, like organic matter import, and internal factors like the morphology and hydrodynamics of the receiving tidal basin. For instance, benthic nutrients from remineralized organic matter may be more concentrated in shallow basins or diluted in basins with high exchange rates. In addition, the location of a monitoring station may determine which basin-specific water masses are actually observed. In the present paper a hydrodynamic intertidal imprint (IMP) is estimated for ten stations in various tidal basins of the Wadden Sea. The fraction of time water masses spent in intertidal areas prior to observation is calculated by linking the Lagrangian transport module PELETS to already existing hourly reconstructions of currents between 1959 and 2003. Irrespective of water depth, additional calculations of mean residence times (MRT) in the Wadden Sea indicate whether, in the case of low IMP values, water masses originate from coastal areas or tidal channels. Results show distinct regional differences, with highest values in the eastern part of the Dutch sector of the southern Wadden Sea (IMP=77%, MRT=99%) and lowest values in the German/Danish sector of the northern Wadden Sea (IMP=1.1%, MRT=21%). The IMP correlates positively with observed nutrient levels (R2=0.83). Evidently, this residence time-based intertidal signal is pivotal in explaining regional variations in eutrophication levels revealed by long-term comparative data from different monitoring stations.

  7. Tensegrity architecture explains linear stiffening and predicts softening of living cells.

    Science.gov (United States)

    Volokh, K Y; Vilnay, O; Belsky, M

    2000-12-01

    The problem of theoretical explanation of the experimentally observed linear stiffening of living cells is addressed. This explanation is based on Ingber's assumption that the cell cytoskeleton, which enjoys tensegrity architecture with compressed microtubules that provide tension to the microfilaments, affects the mechanical behavior of the living cell. Moreover, it is shown that the consideration of the extreme flexibility of microtubules and the unilateral response of microfilaments is crucial for the understanding of the living cell overall behavior. Formal nonlinear structural analysis of the cell cytoskeleton under external mechanical loads is performed. For this purpose, a general computer model for tensegrity assemblies with unilateral microfilaments and buckled microtubules is developed and applied to the theoretical analysis of the mechanical response of 2D and 3D examples of tensegrity cells mimicking the behavior of real living cells. Results of the computer simulations explain the experimentally observed cell stiffening. Moreover, the theoretical results predict the possible existence of a transient softening behavior of cells, a phenomenon, which has not been observed in experiments yet.

  8. Apparent enrichment of organically bound tritium in rivers explained by the heritage of our past.

    Science.gov (United States)

    Eyrolle-Boyer, Frédérique; Boyer, Patrick; Claval, David; Charmasson, Sabine; Cossonnet, Catherine

    2014-10-01

    The global inventory of naturally produced tritium (3H) is estimated at 2.65 kg, whereas more than 600 kg have been released during atmospheric nuclear tests (NCRP, 1979; UNSCEAR, 2000) constituting the main source of artificial tritium throughout the Anthropocene. The behaviour of this radioactive isotope in the environment has been widely studied since the 1950s, both through laboratory experiments and, more recently, through field observations (e.g., Cline, 1953; Kirchmann et al., 1979; Daillant et al., 2004; McCubbin et al., 2001; Kim et al., 2012). In its "free" forms, [i.e. 3H gas or 3H hydride (HT); methyl 3H gas (CH3T); tritiated H2O or 3H-oxide (HTO); and Tissue Free Water 3H (TFWT)], tritium closely follows the water cycle. However, 3H bound with organic compounds, mainly during the basic stages of photosynthesis or through weak hydrogen links, is less exchangeable with water, which explains its persistence in the carbon cycle as re underlined recently by Baglan et al. (2013), Jean-Batiste and Fourré (2013), Kim et al. (2013a,b). In this paper, we demonstrate that terrestrial biomass pools, historically contaminated by global atmospheric fallout from nuclear testing, have constituted a significant delayed source of organically bound tritium (OBT) for aquatic systems, resulting in an apparent enrichment of OBT as compared to HTO. This finding helps to explain concentration factors (tritium concentration in biota/concentration in water) greater than 1 observed in areas that are not directly affected by industrial radioactive wastes, and thus sheds light on the controversies regarding tritium 'bioaccumulation'. Such apparent enrichment of OBT is expected to be more pronounced in the Northern Hemisphere where fallout was most significant, depending on the nature and biodegradability of terrestrial biomass at the regional scale. We further believe that OBT transfers from the continent to oceans have been sufficient to affect tritium concentrations in

  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. Supernovae and how to observe them

    CERN Document Server

    Mobberley, Martin

    2007-01-01

    Supernovae represent the most violent stellar explosions in the universe. This book presents supernovo facts and explains what they are, and how to observe and discover them. It contains detailed galaxy images and is aimed at amateur astronomers who are readers of astronomy periodicals.

  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. Microwave Oven Observations.

    Science.gov (United States)

    Sumrall, William J.; Richardson, Denise; Yan, Yuan

    1998-01-01

    Explains a series of laboratory activities which employ a microwave oven to help students understand word problems that relate to states of matter, collect data, and calculate and compare electrical costs to heat energy costs. (DDR)

  13. Can muon-induced backgrounds explain the DAMA data?

    Science.gov (United States)

    Klinger, Joel; Kudryavtsev, Vitaly A.

    2016-05-01

    We present an accurate simulation of the muon-induced background in the DAMA/LIBRA experiment. Muon sampling underground has been performed using the MUSIC/MUSUN codes and subsequent interactions in the rock around the DAMA/LIBRA detector cavern and the experimental setup including shielding, have been simulated with GEANT4.9.6. In total we simulate the equivalent of 20 years of muon data. We have calculated the total muon-induced neutron flux in the DAMA/LIBRA detector cavern as Φμ n = 1.0 × 10-9 cm-2s-1, which is consistent with other simulations. After selecting events which satisfy the DAMA/LIBRA signal criteria, our simulation predicts 3.49 × 10-5 cpd/kg/keV which accounts for less than 0.3% of the DAMA/LIBRA modulation amplitude. We conclude from our work that muon-induced backgrounds are unable to contribute to the observed signal modulation.

  14. Racial factors cannot explain superior Japanese outcomes in stomach cancer.

    Science.gov (United States)

    Hundahl, S A; Stemmermann, G N; Oishi, A

    1996-02-01

    To compare the stage-stratified survival of Japanese patients treated in Honolulu according to Western techniques with that of Japanese patients treated in Tokyo according to Japanese techniques, thus eliminating race as a potentially confounding variable. Of 312 Honolulu Japanese patients surviving Western-type gastric resection for neoplasm between 1974 and 1985, 279 were identified with invasive gastric adenocarcinoma unassociated with any second malignancy. This Honolulu cohort, treated by Western methods, was retrospectively compared with a similar, previously described cohort of 3176 Tokyo Japanese patients treated according to Japanese methods. American Joint Committee on Cancer/Union Internationale Contre le Cancer criteria for stage-stratified survival. Despite non-TNM prognostic factors favoring higher survival for the Honolulu Japanese patients, for every TNM stage, we observed higher survival for the Tokyo Japanese patients who were treated according to Japanese techniques. For stage I disease, the survival rates were 86% vs 96%, respectively (P migration and/or differing therapeutic efficacy seem more likely explanations.

  15. Combined Alzheimer's disease and cerebrovascular staging explains advanced dementia cognition.

    Science.gov (United States)

    Zea-Sevilla, María Ascensión; Fernández-Blázquez, Miguel Angel; Calero, Miguel; Bermejo-Velasco, Pedro; Rábano, Alberto

    2015-11-01

    The absence of a consensus system for full neuropathological evaluation limits clinicopathological studies and comparability between laboratories. Combined staging for Alzheimer's type and cerebral vascular pathology may allow a better classification of cases for clinical and cognitive correlation. Cognitive and postmortem neuropathological data were obtained from 70 brains donated to the Tissue Bank of the Centro de Investigación de Enfermedades Neurológicas (CIEN) Foundation according to recently developed staging schemes for Alzheimer's type and vascular pathology. Subjects belonged to a cohort of institutionalized patients with moderate or severe dementia and a mean follow-up period of 7 years. Cases were classified into three groups: Alzheimer's predominant (64.1%), vascular predominant (6.3%) and mixed pathology (29.6%). Significant differences were observed in Severe Mini-Mental State Examination and verbal fluency between the vascular predominant and the other groups of patients. The combination of scales measuring cerebral vascular and Alzheimer's type pathology allowed a classification of patients that reveals differences between groups in premortem cognitive features. Copyright © 2015 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

  16. Cell formation by myxozoan species is not explained by dogma.

    Science.gov (United States)

    Morris, David J

    2010-08-22

    Eukaryotes form new cells through the replication of nuclei followed by cytokinesis. A notable exception is reported from the class Myxosporea of the phylum Myxozoa. This assemblage of approximately 2310 species is regarded as either basal bilaterian or cnidarian, depending on the phylogenetic analysis employed. For myxosporeans, cells have long been regarded as forming within other cells by a process referred to as endogenous budding. This would involve a nucleus forming endoplasmic reticulum around it, which transforms into a new plasma membrane, thus enclosing and separating it from the surrounding cell. This remarkable process, unique within the Metazoa, is accepted as occurring within stages found in vertebrate hosts, but has only been inferred from those stages observed within invertebrate hosts. Therefore, I conducted an ultrastructural study to examine how internal cells are formed by a myxosporean parasitizing an annelid. In this case, actinospore parasite stages clearly internalized existing cells; a process with analogies to the acquisition of endosymbiotic algae by cnidarian species. A subsequent examination of the myxozoan literature did not support endogenous budding, indicating that this process, which has been a central tenet of myxozoan developmental biology for over a century, is dogma.

  17. Nutrient excess and autophagic deficiency: explaining metabolic diseases in obesity.

    Science.gov (United States)

    van Niekerk, Gustav; duToit, André; Loos, Ben; Engelbrecht, Anna-Mart

    2017-12-28

    Over-nutrition and a sedentary lifestyle are the driving forces behind the development of metabolic diseases. Conversely, caloric restriction and exercise have proven to be the most effective strategies in combating metabolic diseases. Interestingly, exercise and caloric restriction share a common feature: both represent a potent mechanism for upregulating autophagy. Autophagy is rapidly induced by nutrient deprivation, and conversely, inactivated by amino acids as well as growth factors (e.g. insulin). Here, we review evidence demonstrating that autophagy may indeed be attenuated in metabolic tissue such as liver, muscle, and adipose, in the context of obesity. We also highlight the mechanistic basis by which defective autophagy may contribute to the manifestation of metabolic diseases. This includes a compromised ability of the cell to perform quality control on the mitochondrial matrix, since autophagy plays a pivotal role in the degradation of defective mitochondria. Similarly, autophagy also plays an indispensable role in the clearance of protein aggregates and redundant large protein platforms such as inflammasomes. Autophagy might also play a key role in the metabolism of endotoxins, implicating the importance of autophagy in the pathogenesis of metabolic endotoxemia. These observations underpin an unprecedented role of autophagy in the manifestation of obesity-induced metabolic derangement. Copyright © 2017. Published by Elsevier Inc.

  18. Protein Biophysics Explains Why Highly Abundant Proteins Evolve Slowly

    Directory of Open Access Journals (Sweden)

    Adrian W.R. Serohijos

    2012-08-01

    Full Text Available The consistent observation across all kingdoms of life that highly abundant proteins evolve slowly demonstrates that cellular abundance is a key determinant of protein evolutionary rate. However, other empirical findings, such as the broad distribution of evolutionary rates, suggest that additional variables determine the rate of protein evolution. Here, we report that under the global selection against the cytotoxic effects of misfolded proteins, folding stability (ΔG, simultaneous with abundance, is a causal variable of evolutionary rate. Using both theoretical analysis and multiscale simulations, we demonstrate that the anticorrelation between the premutation ΔG and the arising mutational effect (ΔΔG, purely biophysical in origin, is a necessary requirement for abundance–evolutionary rate covariation. Additionally, we predict and demonstrate in bacteria that the strength of abundance–evolutionary rate correlation depends on the divergence time separating reference genomes. Altogether, these results highlight the intrinsic role of protein biophysics in the emerging universal patterns of molecular evolution.

  19. Can sleep deprivation studies explain why human adults sleep?

    Science.gov (United States)

    Brown, Lee K

    2012-11-01

    This review will concentrate on the consequences of sleep deprivation in adult humans. These findings form a paradigm that serves to demonstrate many of the critical functions of the sleep states. The drive to obtain food, water, and sleep constitutes important vegetative appetites throughout the animal kingdom. Unlike nutrition and hydration, the reasons for sleep have largely remained speculative. When adult humans are nonspecifically sleep-deprived, systemic effects may include defects in cognition, vigilance, emotional stability, risk-taking, and, possibly, moral reasoning. Appetite (for foodstuffs) increases and glucose intolerance may ensue. Procedural, declarative, and emotional memory are affected. Widespread alterations of immune function and inflammatory regulators can be observed, and functional MRI reveals profound changes in regional cerebral activity related to attention and memory. Selective deprivation of rapid eye movement (REM) sleep, on the contrary, appears to be more activating and to have lesser effects on immunity and inflammation. The findings support a critical need for sleep due to the widespread effects on the adult human that result from nonselective sleep deprivation. The effects of selective REM deprivation appear to be different and possibly less profound, and the functions of this sleep state remain enigmatic.

  20. The neritic benthopelagic fauna: Which factors explain nocturnal distribution better?

    Science.gov (United States)

    Vereshchaka, Alexander L.; Anokhina, Ludmila L.

    2017-08-01

    Nocturnal sampling of mesoplankton above different biotopes at depths of 10, 20, and 40 m, with a temporal resolution of 10 min (98 hauls) was made and 76 taxa were identified. Six environmental factors were tested as the proximate cues for the distribution of individual taxa and integral community parameters: type of sea-floor biotope/depth (SFB), temperature (T), time after sunset (TAS), residual solar illumination, (assessed as time to midnight, TTM), moon phase (MP), and moon altitude (MA). Canonical Correspondence Analyses (CCAs), Bray-Curtis analyses (BCAs), and one-way ANOSIM and SIMPER tests were used to assess the impact of the environmental factors on the distribution of individual taxa, integral community parameters, and community structure. Seventy six taxa were recorded, with 17 taxa, mostly decapod larvae, contributing >1% of the total amount of sampled individuals. Four decapod species comprised over 50% of the total benthopelagic abundance. Decapod larvae migrated as benthopelagic fauna and aggregated over sites where adults live; this behaviour was observed both in zoea and in megalopa stages (ANOVA and SIMPER tests). SFB, T, and TTM are the best proximate cues for the nocturnal distribution of the neritic benthopelagic fauna. Significance of environmental factors may change with depth and sea-floor biotope type: T and TTM are equally important above all explored depths; impact of TAS decreased and contribution of MP and MA increased above greater depths. Further studies of the mesoplanktonic samples, which yield greatly richer material than macroplanktonic samples, may favour this analysis.

  1. A hypothesis to explain childhood cancers near nuclear power plants.

    Science.gov (United States)

    Fairlie, Ian

    2014-07-01

    Over 60 epidemiological studies world-wide have examined cancer incidences in children near nuclear power plants (NPPs): most of them indicate leukemia increases. These include the 2008 KiKK study commissioned by the German Government which found relative risks (RR) of 1.6 in total cancers and 2.2 in leukemias among infants living within 5 km of all German NPPs. The KiKK study has retriggered the debate as to the cause(s) of these increased cancers. A suggested hypothesis is that the increased cancers arise from radiation exposures to pregnant women near NPPs. However any theory has to account for the >10,000 fold discrepancy between official dose estimates from NPP emissions and observed increased risks. An explanation may be that doses from spikes in NPP radionuclide emissions are significantly larger than those estimated by official models which are diluted through the use of annual averages. In addition, risks to embryos/fetuses are greater than those to adults and haematopoietic tissues appear more radiosensitive in embryos/fetuses than in newborn babies. The product of possible increased doses and possible increased risks per dose may provide an explanation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Structural Differences Explain Diverse Functions of Plasmodium Actins

    Science.gov (United States)

    Vahokoski, Juha; Martinez, Silvia Muñico; Ignatev, Alexander; Lepper, Simone; Frischknecht, Friedrich; Sidén-Kiamos, Inga; Sachse, Carsten; Kursula, Inari

    2014-01-01

    Actins are highly conserved proteins and key players in central processes in all eukaryotic cells. The two actins of the malaria parasite are among the most divergent eukaryotic actins and also differ from each other more than isoforms in any other species. Microfilaments have not been directly observed in Plasmodium and are presumed to be short and highly dynamic. We show that actin I cannot complement actin II in male gametogenesis, suggesting critical structural differences. Cryo-EM reveals that Plasmodium actin I has a unique filament structure, whereas actin II filaments resemble canonical F-actin. Both Plasmodium actins hydrolyze ATP more efficiently than α-actin, and unlike any other actin, both parasite actins rapidly form short oligomers induced by ADP. Crystal structures of both isoforms pinpoint several structural changes in the monomers causing the unique polymerization properties. Inserting the canonical D-loop to Plasmodium actin I leads to the formation of long filaments in vitro. In vivo, this chimera restores gametogenesis in parasites lacking actin II, suggesting that stable filaments are required for exflagellation. Together, these data underline the divergence of eukaryotic actins and demonstrate how structural differences in the monomers translate into filaments with different properties, implying that even eukaryotic actins have faced different evolutionary pressures and followed different paths for developing their polymerization properties. PMID:24743229

  3. to Explain the Gender Paradox of French Centenarians

    Directory of Open Access Journals (Sweden)

    Frédéric Balard

    2011-01-01

    Full Text Available Since the 1990s, several studies involving French centenarians have shown a gender paradox in old age. Even if women are more numerous in old age and live longer than men, men are in better physical and cognitive health, are higher functioning, and have superior vision. If better health should lead to a longer life, why are men not living longer than women? This paper proposes a hypothesis based on the differences in the generational habitus between men and women who were born at the beginning of the 20th century. The concept of generational habitus combines the generation theory of Mannheim with the habitus concept of Bourdieu based on the observation that there exists a way of being, thinking, and doing for each generation. We hypothesized that this habitus still influences many gender-linked behaviours in old age. Men, as “oaks,” seem able to delay the afflictions of old age until a breaking point, while women, as “reeds,” seem able to survive despite an accumulation of health deficits.

  4. Sleep, recovery, and metaregulation: explaining the benefits of sleep

    Directory of Open Access Journals (Sweden)

    Vyazovskiy VV

    2015-12-01

    Full Text Available Vladyslav V VyazovskiyDepartment of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, UKAbstract: A commonly held view is that extended wakefulness is causal for a broad spectrum of deleterious effects at molecular, cellular, network, physiological, psychological, and behavioral levels. Consequently, it is often presumed that sleep plays an active role in providing renormalization of the changes incurred during preceding waking. Not surprisingly, unequivocal empirical evidence supporting such a simple bi-directional interaction between waking and sleep is often limited or controversial. One difficulty is that, invariably, a constellation of many intricately interrelated factors, including the time of day, specific activities or behaviors during preceding waking, metabolic status and stress are present at the time of measurement, shaping the overall effect observed. In addition to this, although insufficient or disrupted sleep is thought to prevent efficient recovery of specific physiological variables, it is also often difficult to attribute specific changes to the lack of sleep proper. Furthermore, sleep is a complex phenomenon characterized by a multitude of processes, whose unique and distinct contributions to the purported functions of sleep are difficult to determine, because they are interrelated. Intensive research effort over the last decades has greatly progressed current understanding of the cellular and physiological processes underlying the regulation of vigilance states. Notably, it also highlighted the infinite complexity within both waking and sleep, and revealed a number of fundamental conceptual and technical obstacles that need to be overcome in order to fully understand these processes. A promising approach could be to view sleep not as an entity, which has specific function(s and is subject to direct regulation, but as a manifestation of the process of metaregulation, which enables efficient moment

  5. Sleep, recovery, and metaregulation: explaining the benefits of sleep.

    Science.gov (United States)

    Vyazovskiy, Vladyslav V

    2015-01-01

    A commonly held view is that extended wakefulness is causal for a broad spectrum of deleterious effects at molecular, cellular, network, physiological, psychological, and behavioral levels. Consequently, it is often presumed that sleep plays an active role in providing renormalization of the changes incurred during preceding waking. Not surprisingly, unequivocal empirical evidence supporting such a simple bi-directional interaction between waking and sleep is often limited or controversial. One difficulty is that, invariably, a constellation of many intricately interrelated factors, including the time of day, specific activities or behaviors during preceding waking, metabolic status and stress are present at the time of measurement, shaping the overall effect observed. In addition to this, although insufficient or disrupted sleep is thought to prevent efficient recovery of specific physiological variables, it is also often difficult to attribute specific changes to the lack of sleep proper. Furthermore, sleep is a complex phenomenon characterized by a multitude of processes, whose unique and distinct contributions to the purported functions of sleep are difficult to determine, because they are interrelated. Intensive research effort over the last decades has greatly progressed current understanding of the cellular and physiological processes underlying the regulation of vigilance states. Notably, it also highlighted the infinite complexity within both waking and sleep, and revealed a number of fundamental conceptual and technical obstacles that need to be overcome in order to fully understand these processes. A promising approach could be to view sleep not as an entity, which has specific function(s) and is subject to direct regulation, but as a manifestation of the process of metaregulation, which enables efficient moment-to-moment integration between internal and external factors, preceding history and current homeostatic needs.

  6. Stress Redistribution Explains Anti-correlated Subglacial Pressure Variations

    Directory of Open Access Journals (Sweden)

    Pierre-Marie Lefeuvre

    2018-01-01

    Full Text Available We used a finite element model to interpret anti-correlated pressure variations at the base of a glacier to demonstrate the importance of stress redistribution in the basal ice. We first investigated two pairs of load cells installed 20 m apart at the base of the 210 m thick Engabreen glacier in Northern Norway. The load cell data for July 2003 showed that pressurisation of a subglacial channel located over one load cell pair led to anti-correlation in pressure between the two pairs. To investigate the cause of this anti-correlation, we used a full Stokes 3D model of a 210 m thick and 25–200 m wide glacier with a pressurised subglacial channel represented as a pressure boundary condition. The model reproduced the anti-correlated pressure response at the glacier bed and variations in pressure of the same order of magnitude as the load cell observations. The anti-correlation pattern was shown to depend on the bed/surface slope. On a flat bed with laterally constrained cross-section, the resulting bridging effect diverted some of the normal forces acting on the bed to the sides. The anti-correlated pressure variations were then reproduced at a distance >10–20 m from the channel. In contrast, when the bed was inclined, the channel support of the overlying ice was vertical only, causing a reduction of the normal stress on the bed. With a bed slope of 5 degrees, the anti-correlation occurred within 10 m of the channel. The model thus showed that the effect of stress redistribution can lead to an opposite response in pressure at the same distance from the channel and that anti-correlation in pressure is reproduced without invoking cavity expansion caused by sliding.

  7. Observation on foreshore morphodynamics of microtidal sandy beaches

    Digital Repository Service at National Institute of Oceanography (India)

    Dora, G.U.; SanilKumar, V.; Philip, C.S.; Johnson, G.

    -annual period, whereas the annual average beach morphology was similar. The obser- vation on morphodynamics explains that the beaches are annually cyclic, where slow rate of sediment accretion and/or erosion processes is observed during the consecu- tive...

  8. Mechanisms explaining nursery habitat association: how do juvenile snapper (Chrysophrys auratus benefit from their nursery habitat?

    Directory of Open Access Journals (Sweden)

    Darren M Parsons

    Full Text Available Nursery habitats provide elevated survival and growth to the organisms that associate with them, and as such are a crucial early life-stage component for many fishes and invertebrates. The exact mechanisms by which these benefits are afforded to associated organisms, however, are often unclear. Here we assessed potential explanations of the nursery function of structurally complex habitats for post-settlement snapper, Chrysophrys auratus, in New Zealand. Specifically, we deployed Artificial Seagrass Units (ASUs and used a combination of video observation, netting and diet analysis of associated post-settlement snapper as well describing potential prey within the micro-habitats surrounding ASUs. We did not observe any predation attempts and few potential predators, suggesting that for snapper the nursery value of structurally complex habitats is not as a predation refuge. The diet of post-settlement snapper mostly consisted of calanoid and cyclopoid copepods, which were most commonly sampled from within the water column. Nearly all suspected feeding events were also observed within the water column. When considering the velocity of water flow at each ASU, plankton sampling revealed a greater availability of copepods with increasing current strength, while netting and video observation demonstrated that the abundance of snapper was highest at sites with intermediate water velocity. This study highlights that the interaction between water flow and food availability may represent an important trade-off between energy expenditure and food intake for post-settlement snapper. Structurally complex habitats may mediate this relationship, allowing snapper to access sites with higher food availability while reducing swimming costs. This mechanism may have broader relevance, potentially explaining the importance of estuarine nursery habitats for other species.

  9. Mechanisms explaining nursery habitat association: how do juvenile snapper (Chrysophrys auratus) benefit from their nursery habitat?

    Science.gov (United States)

    Parsons, Darren M; Middleton, Crispin; Spong, Keren T; Mackay, Graeme; Smith, Matt D; Buckthought, Dane

    2015-01-01

    Nursery habitats provide elevated survival and growth to the organisms that associate with them, and as such are a crucial early life-stage component for many fishes and invertebrates. The exact mechanisms by which these benefits are afforded to associated organisms, however, are often unclear. Here we assessed potential explanations of the nursery function of structurally complex habitats for post-settlement snapper, Chrysophrys auratus, in New Zealand. Specifically, we deployed Artificial Seagrass Units (ASUs) and used a combination of video observation, netting and diet analysis of associated post-settlement snapper as well describing potential prey within the micro-habitats surrounding ASUs. We did not observe any predation attempts and few potential predators, suggesting that for snapper the nursery value of structurally complex habitats is not as a predation refuge. The diet of post-settlement snapper mostly consisted of calanoid and cyclopoid copepods, which were most commonly sampled from within the water column. Nearly all suspected feeding events were also observed within the water column. When considering the velocity of water flow at each ASU, plankton sampling revealed a greater availability of copepods with increasing current strength, while netting and video observation demonstrated that the abundance of snapper was highest at sites with intermediate water velocity. This study highlights that the interaction between water flow and food availability may represent an important trade-off between energy expenditure and food intake for post-settlement snapper. Structurally complex habitats may mediate this relationship, allowing snapper to access sites with higher food availability while reducing swimming costs. This mechanism may have broader relevance, potentially explaining the importance of estuarine nursery habitats for other species.

  10. Thai visitors’ expectations and experiences of explainer interaction within a science museum context

    Science.gov (United States)

    Chen, Ganigar; Sonchaeng, Pichai; Wilkinson, Clare; Willey, Neil; Bultitude, Karen

    2015-01-01

    In Western literature, there is evidence that museum explainers offer significant potential for enhancing visitors’ learning through influencing their knowledge, content, action, behaviour and attitudes. However, little research has focused on the role of explainers in other cultural contexts. This study explored interactions between visitors and museum explainers within the setting of Thailand. Two questionnaires were distributed to 600 visitors and 41 museum explainers. The results demonstrated both potential similarities and differences with Western contexts. Explainers appeared to prefer didactic approaches, focussing on factual knowledge rather than encouraging deep learning. Two-way communication, however, appeared to be enhanced by the use of a ‘pseudo-sibling relationship’ by explainers. Traditional Thai social reserve was reduced through such approaches, with visitors taking on active learning roles. These findings have implications for training museum explainers in non-Western cultures, as well as museum communication practice more generally. PMID:24751689

  11. Thai visitors' expectations and experiences of explainer interaction within a science museum context.

    Science.gov (United States)

    Kamolpattana, Supara; Chen, Ganigar; Sonchaeng, Pichai; Wilkinson, Clare; Willey, Neil; Bultitude, Karen

    2015-01-01

    In Western literature, there is evidence that museum explainers offer significant potential for enhancing visitors' learning through influencing their knowledge, content, action, behaviour and attitudes. However, little research has focused on the role of explainers in other cultural contexts. This study explored interactions between visitors and museum explainers within the setting of Thailand. Two questionnaires were distributed to 600 visitors and 41 museum explainers. The results demonstrated both potential similarities and differences with Western contexts. Explainers appeared to prefer didactic approaches, focussing on factual knowledge rather than encouraging deep learning. Two-way communication, however, appeared to be enhanced by the use of a 'pseudo-sibling relationship' by explainers. Traditional Thai social reserve was reduced through such approaches, with visitors taking on active learning roles. These findings have implications for training museum explainers in non-Western cultures, as well as museum communication practice more generally. © The Author(s) 2014.

  12. Do clones degenerate over time? Explaining the genetic variability of asexuals through population genetic models

    Directory of Open Access Journals (Sweden)

    Drozd Pavel

    2011-03-01

    Full Text Available Abstract Background Quest for understanding the nature of mechanisms governing the life span of clonal organisms lasts for several decades. Phylogenetic evidence for recent origins of most clones is usually interpreted as proof that clones suffer from gradual age-dependent fitness decay (e.g. Muller's ratchet. However, we have shown that a neutral drift can also qualitatively explain the observed distribution of clonal ages. This finding was followed by several attempts to distinguish the effects of neutral and non-neutral processes. Most recently, Neiman et al. 2009 (Ann N Y Acad Sci.:1168:185-200. reviewed the distribution of asexual lineage ages estimated from a diverse array of taxa and concluded that neutral processes alone may not explain the observed data. Moreover, the authors inferred that similar types of mechanisms determine maximum asexual lineage ages in all asexual taxa. In this paper we review recent methods for distinguishing the effects of neutral and non-neutral processes and point at methodological problems related with them. Results and Discussion We found that contemporary analyses based on phylogenetic data are inadequate to provide any clear-cut answer about the nature and generality of processes affecting evolution of clones. As an alternative approach, we demonstrate that sequence variability in asexual populations is suitable to detect age-dependent selection against clonal lineages. We found that asexual taxa with relatively old clonal lineages are characterised by progressively stronger deviations from neutrality. Conclusions Our results demonstrate that some type of age-dependent selection against clones is generally operational in asexual animals, which cover a wide taxonomic range spanning from flatworms to vertebrates. However, we also found a notable difference between the data distribution predicted by available models of sequence evolution and those observed in empirical data. These findings point at the

  13. Visual impairment and blindness in spanish adults: geographic inequalities are not explained by age or education.

    Science.gov (United States)

    Rius, Anna; Artazcoz, Lucía; Guisasola, Laura; Benach, Joan

    2014-01-01

    The objectives of this study were to examine for the first time the prevalence of visual impairment and blindness among adults in Spain, to explore regional differences, and to assess whether they may vary as a function of sex or be explained by age and individual or regional socioeconomic position. Data were obtained from the 2008 Spanish Survey on Disability, Personal Autonomy, and Dependency Situations, a cross-sectional survey based on a representative sample of the noninstitutionalized population of Spain. The sample was composed of 213 626 participants aged ≥15 years (103 093 men and 110 533 women); 360 were blind (160 men and 200 women), 4048 had near visual impairment (1397 men and 2651 women), and 4034 had distance visual impairment (1445 men and 2589 women). The prevalence of near and distance visual impairment was calculated for each region. Multiple logistic regression models were fitted to calculate odds ratios and 95% confidence intervals. All analyses were stratified by sex. Visual impairment was based on 3 questions aimed at identifying blindness and near and distance visual impairment. The prevalence (percentage) of blindness was 0.17 (men, 0.16; women, 0.18): 1.89 for near visual impairment (men, 1.36; women, 2.40), 1.89 for distance visual impairment (men, 1.40; women, 2.34), and 2.43 for any visual impairment (men, 1.81; women, 3.02). Regional inequalities in the prevalence of visual impairment were observed, correlated with regional income, and the prevalence was consistently higher among women than men. The magnitude of the inequalities remained after adjusting for age and educational level, and a north-to-south pattern of increasing prevalence was observed. Regional and sex inequalities in the prevalence of visual impairment and blindness were observed in Spain, with a north-to-south gradient of increasing prevalence that was not explained by age or individual educational level but was correlated with regional level of economic

  14. Explaining the diverse response of ultra-relativistic Van Allen belt electrons to solar wind forcing

    Science.gov (United States)

    Mann, Ian; Ozeke, Louis; Murphy, Kyle; Claudepierre, Seth; Rae, Jonathan; Milling, David; Kale, Andy; Baker, Daniel

    2017-04-01

    The NASA Van Allen Probes have opened a new window on the dynamics of ultra-relativistic electrons in the Van Allen radiation belts. Under different solar wind forcing the outer belt is seen to respond in a variety of apparently diverse and sometimes remarkable ways. For example, sometimes a third radiation belt is carved out (e.g., September 2012), or the belts can remain depleted for 10 days or more (September 2014). More usually there is a sequential response of a strong and sometimes rapid depletion followed by a re-energization, the latter increasing outer belt electron flux by orders of magnitude on hour timescales during some of the strongest storms of this solar cycle (e.g., March 2013, March 2015). Such dynamics also appear to be always bounded at low-L by an apparently impenetrable barrier below L 2.8 through which ultra-relativistic electrons do not penetrate. Many studies in the Van Allen Probes era have sought explanations for these apparently diverse features, often incorporating the effects from multiple plasma waves. In contrast, we show how this apparently diverse behaviour can instead be explained by one simple dominant process: ULF wave radial transport. Once ULF wave transport rates are accurately specified by observations, and coupled to the dynamical variation of the outer boundary condition at the edge of the outer belt, the observed diverse responses can all be explained. In order to get good agreement with observations, the modeling reveals the importance of still currently unexplained fast loss in the main phase which decouples pre- and post-storm ultra-relativistic electron flux on hour timescales. Similarly, varying plasmasheet source populations are seen to be of critical importance such that near-tail dynamics likely play a crucial role in Van Allen belt dynamics. Nonetheless, simple models incorporating accurate transport rates derived directly from ULF wave measurements are shown to provide a single natural and compelling explanation

  15. Explaining global surface aerosol number concentrations in terms of primary emissions and particle formation

    Directory of Open Access Journals (Sweden)

    D. V. Spracklen

    2010-05-01

    Full Text Available We synthesised observations of total particle number (CN concentration from 36 sites around the world. We found that annual mean CN concentrations are typically 300–2000 cm−3 in the marine boundary layer and free troposphere (FT and 1000–10 000 cm−3 in the continental boundary layer (BL. Many sites exhibit pronounced seasonality with summer time concentrations a factor of 2–10 greater than wintertime concentrations. We used these CN observations to evaluate primary and secondary sources of particle number in a global aerosol microphysics model. We found that emissions of primary particles can reasonably reproduce the spatial pattern of observed CN concentration (R2=0.46 but fail to explain the observed seasonal cycle (R2=0.1. The modeled CN concentration in the FT was biased low (normalised mean bias, NMB=−88% unless a secondary source of particles was included, for example from binary homogeneous nucleation of sulfuric acid and water (NMB=−25%. Simulated CN concentrations in the continental BL were also biased low (NMB=−74% unless the number emission of anthropogenic primary particles was increased or a mechanism that results in particle formation in the BL was included. We ran a number of simulations where we included an empirical BL nucleation mechanism either using the activation-type mechanism (nucleation rate, J, proportional to gas-phase sulfuric acid concentration to the power one or kinetic-type mechanism (J proportional to sulfuric acid to the power two with a range of nucleation coefficients. We found that the seasonal CN cycle observed at continental BL sites was better simulated by BL particle formation (R2=0.3 than by increasing the number emission from primary anthropogenic sources (R2=0.18. The nucleation constants that resulted in best overall match between model and observed CN concentrations were

  16. Explaining the excess mortality in Scotland compared with England: pooling of 18 cohort studies.

    Science.gov (United States)

    McCartney, Gerry; Russ, Tom C; Walsh, David; Lewsey, Jim; Smith, Michael; Smith, George Davey; Stamatakis, Emmanuel; Batty, G David

    2015-01-01

    Mortality in Scotland is higher than in the rest of west and central Europe and is improving more slowly. Relative to England and Wales, the excess is only partially explained by area deprivation. We tested the extent to which sociodemographic, behavioural, anthropometric and biological factors explain the higher mortality in Scotland compared with England. Pooled data from 18 nationally representative cohort studies comprising the Health Surveys for England (HSE) and the Scottish Health Survey (SHS). Cox regression analysis was used to quantify the excess mortality risk in Scotland relative to England with adjustment for baseline characteristics. A total of 193,873 participants with a mean of 9.6 years follow-up gave rise to 21,345 deaths. The age-adjusted and sex-adjusted all-cause mortality HR for Scottish respondents compared with English respondents was 1.40 (95% CI 1.34 to 1.47), which attenuated to 1.29 (95% CI 1.23 to 1.36) with the addition of the baseline socioeconomic and behavioural characteristics. Cause-specific mortality HRs attenuated only marginally to 1.43 (95% 1.28 to 1.60) for ischaemic heart disease, 1.37 (95% CI 1.15 to 1.63) for stroke, 1.41 (95% CI 1.30 to 1.53) for all cancers, 3.43 (95% CI 1.85 to 6.36) for illicit drug-related poisoning and 4.64 (95% CI 3.55 to 6.05) for alcohol-related mortality. The excess was greatest among young adults (16-44 years) and was observed across all occupational social classes with the greatest excess in the unskilled group. Only a quarter of the excess mortality among Scottish respondents could be explained by the available baseline risk factors. Greater understanding is required on the lived experience of poverty, the role of social support, and the historical, environmental, cultural and political influences on health in Scotland. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  17. Sociopolitical and economic elements to explain the environmental performance of countries.

    Science.gov (United States)

    Almeida, Thiago Alexandre das Neves; García-Sánchez, Isabel-María

    2017-01-01

    The present research explains environmental performance using an ecological composite index as the dependent variable and focusing on two national dimensions: sociopolitical characteristics and economics. Environmental performance is measured using the Composite Index of Environmental Performance (CIEP) indicator proposed by García-Sánchez et al. (2015). The first model performs a factor analysis to aggregate the variables according to each analyzed dimension. In the second model, the estimation is run using only single variables. Both models are estimated using generalized least square estimation (GLS) using panel data from 152 countries and 6 years. The results show that sociopolitical factors and international trade have a positive effect on environmental performance. When the variables are separately analyzed, democracy and social policy have a positive effect on environmental performance while transport, infrastructure, consumption of goods, and tourism have a negative effect. Further observation is that the trade-off between importing and exporting countries overshadows the pollution caused by production. It was also observed that infrastructure has a negative coefficient for developing countries and positive for developed countries. The best performances are in the democratic and richer countries that are located in Europe, while the worst environmental performance is by the nondemocratic and the poorest countries, which are on the African continent.

  18. Leaf ontogeny and demography explain photosynthetic seasonality in Amazon evergreen forests

    Science.gov (United States)

    Wu, J.; Albert, L.; Lopes, A. P.; Restrepo-Coupe, N.; Hayek, M.; Wiedemann, K. T.; Guan, K.; Stark, S. C.; Prohaska, N.; Tavares, J. V.; Marostica, S. F.; Kobayashi, H.; Ferreira, M. L.; Campos, K.; Silva, R. D.; Brando, P. M.; Dye, D. G.; Huxman, T. E.; Huete, A. R.; Nelson, B. W.; Saleska, S. R.

    2015-12-01

    Photosynthetic seasonality couples the evolutionary ecology of plant leaves to large-scale rhythms of carbon and water exchanges that are important feedbacks to climate. However, the extent, magnitude, and controls on photosynthetic seasonality of carbon-rich tropical forests are poorly resolved, controversial in the remote sensing literature, and inadequately represented in most earth system models. Here we show that ecosystem-scale phenology (measured by photosynthetic capacity), rather than environmental seasonality, is the primary driver of photosynthetic seasonality at four Amazon evergreen forests spanning gradients in rainfall seasonality, forest composition, and flux seasonality. We further demonstrate that leaf ontogeny and demography explain most of this ecosystem phenology at two central Amazon evergreen forests, using a simple leaf-cohort canopy model that integrates eddy covariance-derived CO2 fluxes, novel near-surface camera-detected leaf phenology, and ground observations of litterfall and leaf physiology. The coordination of new leaf growth and old leaf divestment (litterfall) during the dry season shifts canopy composition towards younger leaves with higher photosynthetic efficiency, driving large seasonal increases (~27%) in ecosystem photosynthetic capacity. Leaf ontogeny and demography thus reconciles disparate observations of forest seasonality from leaves to eddy flux towers to satellites. Strategic incorporation of such whole-plant coordination processes as phenology and ontogeny will improve ecological, evolutionary and earth system theories describing tropical forests structure and function, allowing more accurate representation of forest dynamics and feedbacks to climate in earth system models.

  19. Understanding the role of personality in explaining associations between marital quality and parenting.

    Science.gov (United States)

    Ganiban, Jody M; Ulbricht, Jennifer A; Spotts, Erica L; Lichtenstein, Paul; Reiss, David; Hansson, Kjell; Neiderhiser, Jenae M

    2009-10-01

    Analyses assessed the degrees to which personality accounts for associations between marital quality and parenting and mediates genetic contributions to these relationships. Participants included 318 male and 544 female same-sex twin pairs from the Twin and Offspring Study in Sweden. All twins completed self-report measures of marital quality and personality (anxiousness, aggression, sociability). Composite measures of parent negativity and warmth were derived from the twins' and their adolescent children's ratings of the twins' disciplinary styles and the emotional tone of the parent-child relationship. Observational ratings of marital quality and parenting were also obtained for a subset of twins. Personality characteristics explained 33% to 42% of the covariance between reported marital quality and parenting and 26% to 28% of the covariance between observed marital quality and parenting. For both sets of analyses, personality accounted for more than half of the genetic contributions to covariance between marital quality and parenting. Results indicate that personality significantly contributes to associations between marital quality and parenting and that personality is an important path through which genetic factors contribute to family relationships.

  20. Predictable and predictive emotions: explaining cheap signals and trust re-extension

    Science.gov (United States)

    Schniter, Eric; Sheremeta, Roman M.

    2014-01-01

    Despite normative predictions from economics and biology, unrelated strangers will often develop the trust necessary to reap gains from one-shot economic exchange opportunities. This appears to be especially true when declared intentions and emotions can be cheaply communicated. Perhaps even more puzzling to economists and biologists is the observation that anonymous and unrelated individuals, known to have breached trust, often make effective use of cheap signals, such as promises and apologies, to encourage trust re-extension. We used a pair of trust games with one-way communication and an emotion survey to investigate the role of emotions in regulating the propensity to message, apologize, re-extend trust, and demonstrate trustworthiness. This design allowed us to observe the endogenous emergence and natural distribution of trust-relevant behaviors, remedial strategies used by promise-breakers, their effects on behavior, and subsequent outcomes. We found that emotions triggered by interaction outcomes are predictable and also predict subsequent apology and trust re-extension. The role of emotions in behavioral regulation helps explain why messages are produced, when they can be trusted, and when trust will be re-extended. PMID:25477797