78 FR 21979 - Early Career Doctorates Survey; Extension of Public Comment Period

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-12

... NATIONAL SCIENCE FOUNDATION Early Career Doctorates Survey; Extension of Public Comment Period AGENCY: National Science Foundation. ACTION: Notification of Extension of Public Comment Period. SUMMARY... on establishing the Early Career Doctorates Survey. The original comment date was to end on May 9...

Recommended Format for the Periodic Table of the Elements.

ERIC Educational Resources Information Center

Loening, K. L.

1984-01-01

Presents a new, recommended format for the periodic table which does not use the letters A and B to designate subgroups of elements. Also describes events leading to the adoption of this recommendation. (JM)

Theoretical Aspects of Laser-Induced Periodic Surface Structure Formation,

DTIC Science & Technology

1983-11-01

r AD-A134 875 UNCLASSIFIED THEORETICAL ASPECTS OF LASER -INUUCtl) PtKlUUlt bUKhALt STRUCTURE FORMATION(U) ROCHESTER UNIV NY DEPT OF CHEMISTRY M...UR0CHESTER/DC/83/TR-43 2. COVT ACCESSION NO A. TITLE (and Subllllm) Theoretical Aspects of Laser -Induced Periodic Surface Structure Formation 7...publication in Laser -Controlled Chemical Processing of Surfaces, ed. by A. W. Johnson and D. J. Ehrlich (Elsevier, New York) 19 KEY WORDS (Continue

78 FR 22918 - Early Career Doctorates Survey; Extension of Public Comment Period; Correction

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-17

... NATIONAL SCIENCE FOUNDATION Early Career Doctorates Survey; Extension of Public Comment Period; Correction AGENCY: National Science Foundation. ACTION: Notification of extension of public comment period..., seeking comments on establishing the Early Career Doctorates Survey. The document contained an incorrect...

Star formation in globular clusters and dwarf galaxies and implications for the early evolution of galaxies

NASA Technical Reports Server (NTRS)

Lin, Douglas N. C.; Murray, Stephen D.

1991-01-01

Based upon the observed properties of globular clusters and dwarf galaxies in the Local Group, we present important theoretical constraints on star formation in these systems. These constraints indicate that protoglobular cluster clouds had long dormant periods and a brief epoch of violent star formation. Collisions between protocluster clouds triggered fragmentation into individual stars. Most protocluster clouds dispersed into the Galactic halo during the star formation epoch. In contrast, the large spread in stellar metallicity in dwarf galaxies suggests that star formation in their pregenitors was self-regulated: we propose the protocluster clouds formed from thermal instability in the protogalactic clouds and show that a population of massive stars is needed to provide sufficient UV flux to prevent the collapsing protogalactic clouds from fragmenting into individual stars. Based upon these constraints, we propose a unified scenario to describe the early epochs of star formation in the Galactic halo as well as the thick and thin components of the Galactic disk.

Concept formation: a supportive process for early career nurses.

PubMed

Thornley, Tracey; West, Sandra

2010-09-01

Individuals come to understand abstract constructs such as that of the 'expert' through the formation of concepts. Time and repeated opportunity for observation to support the generalisation and abstraction of the developing concept are essential if the concept is to form successfully. Development of an effective concept of the 'expert nurse' is critical for early career nurses who are attempting to integrate theory, values and beliefs as they develop their clinical practice. This study explores the use of a concept development framework in a grounded theory study of the 'expert nurse'. Qualitative. Using grounded theory methods for data collection and analysis, semi-structured interviews were conducted with registered nurses. The participants were asked to describe their concept of the 'expert nurse' and to discuss their experience of developing this. Participants reported forming their concept of the 'expert nurse', after multiple opportunities to engage with nurses identified as 'expert'. This identification did not necessarily relate to the designated position of the 'expert nurse' or assigned mentors. When the early career nurse does not successfully form a concept of the 'expert nurse', difficulties in personal and professional development including skill/knowledge development may arise. To underpin development of their clinical practice effectively, early career nurses need to be provided with opportunities that facilitate the purposive formation of their own concept of the 'expert nurse'. Formation of this concept is not well supported by the common practice of assigning mentors. Early career nurses must be provided with the time and the opportunity to individually develop and refine their concept of the 'expert nurse'. To achieve this, strategies including providing opportunities to engage with expert nurses and discussion of the process of concept formation and its place in underpinning personal judgments may be of assistance. © 2010 Blackwell Publishing

WATER FORMATION IN THE UPPER ATMOSPHERE OF THE EARLY EARTH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fleury, Benjamin; Carrasco, Nathalie; Marcq, Emmanuel

2015-07-10

The water concentration and distribution in the early Earth's atmosphere are important parameters that contribute to the chemistry and the radiative budget of the atmosphere. If the atmosphere above the troposphere is generally considered as dry, photochemistry is known to be responsible for the production of numerous minor species. Here we used an experimental setup to study the production of water in conditions simulating the chemistry above the troposphere of the early Earth with an atmospheric composition based on three major molecules: N{sub 2}, CO{sub 2}, and H{sub 2}. The formation of gaseous products was monitored using infrared spectroscopy. Watermore » was found as the major product, with approximately 10% of the gas products detected. This important water formation is discussed in the context of the early Earth.« less

Sensitive periods of substance abuse: Early risk for the transition to dependence

PubMed Central

Jordan, Chloe J.; Andersen, Susan L.

2016-01-01

Early adolescent substance use dramatically increases the risk of lifelong substance use disorder (SUD). An adolescent sensitive period evolved to allow the development of risk-taking traits that aid in survival; today these may manifest as a vulnerability to drugs of abuse. Early substance use interferes with ongoing neurodevelopment to induce neurobiological changes that further augment SUD risk. Although many individuals use drugs recreationally, only a small percentage transition to SUD. Current theories on the etiology of addiction can lend insights into the risk factors that increase vulnerability from early recreational use to addiction. Building on the work of others, we suggest individual risk for SUD emerges from an immature PFC combined with hyper-reactivity of reward salience, habit, and stress systems. Early identification of risk factors is critical to reducing the occurrence of SUD. We suggest preventative interventions for SUD that can be either tailored to individual risk profiles and/or implemented broadly, prior to the sensitive adolescent period, to maximize resilience to developing substance dependence. Recommendations for future research include a focus on the juvenile and adolescent periods as well as on sex differences to better understand early risk and identify the most efficacious preventions for SUD. PMID:27840157

Black hole formation in the early Universe

NASA Astrophysics Data System (ADS)

Latif, M. A.; Schleicher, D. R. G.; Schmidt, W.; Niemeyer, J.

2013-08-01

Supermassive black holes with up to a 109 M⊙ dwell in the centres of present-day galaxies, and their presence has been confirmed at z ≥ 6. Their formation at such early epochs is still an enigma. Different pathways have been suggested to assemble supermassive black holes in the first billion years after the big bang. Direct collapse has emerged as a highly plausible scenario to form black holes as it provides seed masses of 105-106 M⊙. Gravitational collapse in atomic cooling haloes with virial temperatures Tvir ≥ 104 K may lead to the formation of massive seed black holes in the presence of an intense background ultraviolet flux. Turbulence plays a central role in regulating accretion and transporting angular momentum. We present here the highest resolution cosmological large eddy simulations to date which track the evolution of high-density regions on scales of 0.25 au beyond the formation of the first peak, and study the impact of subgrid-scale turbulence. The peak density reached in these simulations is 1.2 × 10-8 g cm-3. Our findings show that while fragmentation occasionally occurs, it does not prevent the growth of a central massive object resulting from turbulent accretion and occasional mergers. The central object reaches ˜1000 M⊙ within four free-fall times, and we expect further growth up to 106 M⊙ through accretion in about 1 Myr. The direct collapse model thus provides a viable pathway of forming high-mass black holes at early cosmic times.

Star Formation-Driven Winds in the Early Universe

NASA Astrophysics Data System (ADS)

Peek, Matthew; Lundgren, Britt; Brammer, Gabriel

2018-01-01

Measuring the extent of star formation-driven winds from galaxies in the early universe is crucial for understanding of how galaxies evolve over cosmic time. Using WFC3/IR grism data from the Hubble Space Telescope (HST), we have measured the star formation rates and star formation rate surface densities of several hundred galaxies at redshift (z) = 1, when the universe was roughly half its present age. The galaxies we examine are also probed by background quasars, whose spectra provide information about the extent of metal-enriched gas in their halos. We use a computational pipeline to measure the density of the star formation in each galaxy and correlate these measurements with detections of Mg II absorption in nearby quasar spectra from the Sloan Digital Sky Survey. Our preliminary results support a model in which galaxies with high SFR surface densities drive metal-enriched gas out of the disk and into these galaxies’ extended halos, where that gas is detected in the spectra of more distant quasars.

Formative Evaluation of the Understanding the Early Years Initiative. Final Report

ERIC Educational Resources Information Center

Human Resources and Skills Development Canada, 2009

2009-01-01

This report presents the findings of the formative evaluation of the Understanding the Early Years (UEY) Initiative. The evaluation was conducted to examine issues of implementation and design, early progress in achieving immediate objectives, and issues related to accountability. The evaluation team was also asked to provide preliminary guidance…

Spawning of the kissing loach (Leptobotia curta) is limited to periods following the formation of temporary waters.

PubMed

Abe, Tsukasa; Kobayashi, Ichiro; Kon, Masahiro; Sakamoto, Tatsuya

2007-09-01

The kissing loach, an endangered species surviving only in a few Japanese rivers, spawns in the rice-field areas after migration from rivers in early June. To characterize the environmental conditions required for spawning of the kissing loach, spawning was assessed for two years both by direct observation of spawning behavior and by the appearance of eggs, larvae, and juveniles from June to October. All spawning of the kissing loach was limited to within a couple of days after the formation of temporary waters by remarkable rises in water level. Water temperature and daily rainfall fluctuated during the investigation periods, and no clear relationships with spawning were detected. Furthermore, all spawning was observed only in temporary waters with terrestrial grasses. Thus, spawning of the kissing loach is rigidly limited spatio-temporally to after the formation of temporary waters over terrestrial vegetation. Appropriate management of temporary waters will be crucial for the continued existence of this species.

Polarization dependent formation of femtosecond laser-induced periodic surface structures near stepped features

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murphy, Ryan D.; Torralva, Ben; Adams, David P.

2014-06-09

Laser-induced periodic surface structures (LIPSS) are formed near 110 nm-tall Au microstructured edges on Si substrates after single-pulse femtosecond irradiation with a 150 fs pulse centered near a 780 nm wavelength. We investigate the contributions of Fresnel diffraction from step-edges and surface plasmon polariton (SPP) excitation to LIPSS formation on Au and Si surfaces. For certain laser polarization vector orientations, LIPSS formation is dominated by SPP excitation; however, when SPP excitation is minimized, Fresnel diffraction dominates. The LIPSS orientation and period distributions are shown to depend on which mechanism is activated. These results support previous observations of the laser polarization vectormore » influencing LIPSS formation on bulk surfaces.« less

The Formation of Fe/Mg Smectite Under Mildly Acidic Conditions on Early Mars

NASA Technical Reports Server (NTRS)

Sutter, B.; Golden, D. C.; Ming, Douglas W.; Niles, P. B.

2011-01-01

The detection of Fe/Mg smectites and carbonate in Noachian and early Hesperian terrain of Mars suggests that neutral to mildly alkaline conditions prevailed during the early history of Mars. If early Mars surface geochemical conditions were neutral to moderately alkaline with a denser CO2 atmosphere than today, then large carbonates deposits should be more widely detected in Noachian terrain. Why have so few carbonate deposits been detected compared to Fe/Mg smectites? Fe/Mg smectites on early Mars formed under mildly acidic conditions, which would preclude the extensive formation of carbonate deposits. The goal of the proposed work is to evaluate the formation of Fe/Mg smectites under mildly acidic conditions.

Formation and Properties of Laser-Induced Periodic Surface Structures on Different Glasses.

PubMed

Gräf, Stephan; Kunz, Clemens; Müller, Frank A

2017-08-10

The formation and properties of laser-induced periodic surface structures (LIPSS) was investigated on different technically relevant glasses including fused silica, borosilicate glass, and soda-lime-silicate glass under irradiation of fs-laser pulses characterized by a pulse duration τ = 300 fs and a laser wavelength λ = 1025 nm. For this purpose, LIPSS were fabricated in an air environment at normal incidence with different laser peak fluence, pulse number, and repetition frequency. The generated structures were characterized by using optical microscopy, scanning electron microscopy, focused ion beam preparation and Fast-Fourier transformation. The results reveal the formation of LIPSS on all investigated glasses. LIPSS formation on soda-lime-silicate glass is determined by remarkable melt-formation as an intra-pulse effect. Differences between the different glasses concerning the appearing structures, their spatial period and their morphology were discussed based on the non-linear absorption behavior and the temperature-dependent viscosity. The findings facilitate the fabrication of tailored LIPSS-based surface structures on different technically relevant glasses that could be of particular interest for various applications.

Formation and Properties of Laser-Induced Periodic Surface Structures on Different Glasses

PubMed Central

Kunz, Clemens; Müller, Frank A.

2017-01-01

The formation and properties of laser-induced periodic surface structures (LIPSS) was investigated on different technically relevant glasses including fused silica, borosilicate glass, and soda-lime-silicate glass under irradiation of fs-laser pulses characterized by a pulse duration τ = 300 fs and a laser wavelength λ = 1025 nm. For this purpose, LIPSS were fabricated in an air environment at normal incidence with different laser peak fluence, pulse number, and repetition frequency. The generated structures were characterized by using optical microscopy, scanning electron microscopy, focused ion beam preparation and Fast-Fourier transformation. The results reveal the formation of LIPSS on all investigated glasses. LIPSS formation on soda-lime-silicate glass is determined by remarkable melt-formation as an intra-pulse effect. Differences between the different glasses concerning the appearing structures, their spatial period and their morphology were discussed based on the non-linear absorption behavior and the temperature-dependent viscosity. The findings facilitate the fabrication of tailored LIPSS-based surface structures on different technically relevant glasses that could be of particular interest for various applications. PMID:28796180

Insights from Australian parents into educational experiences in the early postnatal period.

PubMed

McKellar, Lois V; Pincombe, Jan I; Henderson, Ann M

2006-12-01

to investigate the provision of parent education during the early postnatal period in order to gain insight that, through stakeholder collaboration, will contribute to the development of innovative strategies to enhance the provision of postnatal education in a contemporary health-care environment. the study comprises the first stage of an action-research project. The first stage of research sought to explore the experiences of mothers and fathers in the early postnatal period by conducting a questionnaire within 4 weeks of the birth of their baby. The data obtained from the questionnaire is to inform an action-research group for stage two of the project. The Children, Youth and Women's Health Service, a large city maternity hospital in South Australia, covering a range of socio-economic strata. 85 parents completed and returned the questionnaire, comprising 52 mothers and 33 fathers. an anonymous self-report questionnaire was purpose designed to provide each parent with an opportunity to reflect on their own experience, with particular emphasis given to the provision of education and support during the early postnatal period. a number of themes emerged, including a window of opportunity during the postnatal hospital stay to provide education and support, despite the reduction in the length of stay; the need for a family-centred approach to maternity services; and the significance of self and social network in the early transition to parenthood. The findings from this stage of the research, combined with a review of the literature, provide insight that will contribute to stage two of the study. At this stage, an action-research group will continue planning to develop specific actions to enhance the provision of education to parents in the early postnatal period. These actions will subsequently be implemented and assessed.

Fe/Mg smectite formation under acidic conditions on early Mars

NASA Astrophysics Data System (ADS)

Peretyazhko, T. S.; Sutter, B.; Morris, R. V.; Agresti, D. G.; Le, L.; Ming, D. W.

2016-01-01

Phyllosilicates of the smectite group detected in Noachian and early Hesperian terrains on Mars have been hypothesized to form under neutral to alkaline conditions. These pH conditions would also be favorable for formation of widespread carbonate deposits which have not been detected on Mars. We propose that smectite deposits on Mars formed under moderately acidic conditions inhibiting carbonate formation. We report here the first synthesis of Fe/Mg smectite in an acidic hydrothermal system [200 °C, pHRT ∼ 4 (pH measured at room temperature) buffered with acetic acid] from Mars-analogue, glass-rich, basalt simulant with and without aqueous Mg or Fe(II) addition under N2-purged anoxic and ambient oxic redox conditions. Synthesized Fe/Mg smectite was examined by X-ray-diffraction, Mössbauer spectroscopy, visible and near-infrared reflectance spectroscopy, scanning electron microscopy and electron microprobe to characterize mineralogy, morphology and chemical composition. Alteration of the glass phase of basalt simulant resulted in formation of the Fe/Mg smectite mineral saponite with some mineralogical and chemical properties similar to the properties reported for Fe/Mg smectite on Mars. Our experiments are evidence that neutral to alkaline conditions on early Mars are not necessary for Fe/Mg smectite formation as previously inferred. Phyllosilicate minerals could instead have formed under mildly acidic pH conditions. Volcanic SO2 emanation and sulfuric acid formation is proposed as the major source of acidity for the alteration of basaltic materials and subsequent formation of Fe/Mg smectite.

[Hospitals and other philanthropic foundations in early Byzantine period].

PubMed

Yildirim, R Vedat; Ataç, Adnan

Early Byzantine Period includes between A.D. 330 when Constantinople was established and A.D. 518 when Justinus I became emperor. In this time period, a lot of philanthropic foundations such as hospitals, hospices, orphanages, rest homes and soup kitchens are established. Many of patriarchs and religious men opened them. In some of them, it refers to there was patients' care. The oldest hospital in Constantinople was established by Hasios Marcianos, and was next to Saint Irene Church. In addition to this Empress Flacilla wife of Theodosius the Great made hospitals restored and visited patients regularly. Hospitals were not limited in the center of Empire. Hospitals and other philanthropic foundations were established in Antiochia, Alexandria, Nikea, Adrianopolis, Castoria and Jerusalem. The concept of the modern hospital (the actual care, 'hospitality' and treatment of visitors) for the civilian masses in Europe didn't come to fruition until post Constantine and the rise of Christianity. While these early Christian hospitals were grossly over their heads regarding medical capability (they essentially served as last stops for the dying or quarantine centers), the concept of providing care to the public was the actual intent. In this regard, the first civilian hospitals were developed.

Spectroscopic studies of wood fossils from the Crato Formation, Cretaceous Period.

PubMed

da Silva, J H; Freire, P T C; Abagaro, B T O; Silva, J A F; Saraiva, G D; de Lima, F J; Barros, O A; Bantim, R A; Saraiva, A A F; Viana, B C

2013-11-01

In this work we study two types of wood fossils (Gymnosperms, Araucariaceae) from the Crato Formation of Araripe Basin in Brazil, from the Cretaceous Period. The samples were characterized by Raman and infrared spectroscopies, X-ray diffraction and scanning electron microscopy. The results obtained by different techniques showed that although the rocks surrounding the fossils have predominantly the same constitution - calcite - however, the formation processes of these types of wood fossils are quite different. One of the fossils, denominated as light wood, is predominantly composed of gypsum, while the other fossil, the dark wood, is rich in amorphous carbon, possibly the kerogen type. Implications relative to the environment where the plants lived millions years ago are also given. Finally, the results highlight the constitution of one of the most important paleontological sites of the Cretaceous Period in the South America. Copyright © 2013 Elsevier B.V. All rights reserved.

Influence of hepatic load from far-off dry period to early postpartum period on the first postpartum ovulation and accompanying subsequent fertility in dairy cows.

PubMed

Kawashima, Chiho; Ito, Nozomi; Nagashima, Shuntarou; Matsui, Motozumi; Sawada, Kumiko; Schweigert, Florian J; Miyamoto, Akio; Kida, Katsuya

2016-06-17

The aim of the present study was to investigate nutritional and metabolic parameters during the dry and early postpartum periods of ovulatory and anovulatory cows, as well as their postpartum reproductive performance. Blood samples from 20 multiparous Holstein cows were collected once a week from the far-off dry period to 3 weeks postpartum. Early postpartum (0-3 weeks) ovulation was confirmed using plasma progesterone concentration profiles, and cows were considered ovulatory if they had resumed luteal activity by this point (n = 9), whereas cows that had not were considered anovulatory (n = 11). Data from the ovulatory and anovulatory cows were analyzed separately for the far-off dry period (7-4 weeks prepartum), the close-up dry period (3-1 weeks prepartum), and the early postpartum period (0-3 weeks). Serum gamma-glutamyl transpeptidase activity (far-off, P = 0.065; close-up, P = 0.051; and early postpartum, P = 0.030) and aspartate aminotransferase (close-up, P = 0.050 and early postpartum, P = 0.087) activities were higher in anovulatory than in ovulatory cows. The days open period was longer (P = 0.019) in anovulatory than in ovulatory cows, and the number of artificial inseminations per conception (P = 0.025) was greater. In conclusion, we found that continuously high gamma-glutamyl transpeptidase activities in serum, which may be induced by liver disorders, prevent subsequent ovulation and affect subsequent fertility, even if cows obtain sufficient ovulation-related energy and β-carotene.

The Maximum Mass Solar Nebula and the early formation of planets

NASA Astrophysics Data System (ADS)

Nixon, C. J.; King, A. R.; Pringle, J. E.

2018-03-01

Current planet formation theories provide successful frameworks with which to interpret the array of new observational data in this field. However, each of the two main theories (core accretion, gravitational instability) is unable to explain some key aspects. In many planet formation calculations, it is usual to treat the initial properties of the planet forming disc (mass, radius, etc.) as free parameters. In this paper, we stress the importance of setting the formation of planet forming discs within the context of the formation of the central stars. By exploring the early stages of disc formation, we introduce the concept of the Maximum Mass Solar Nebula (MMSN), as opposed to the oft-used Minimum Mass Solar Nebula (here mmsn). It is evident that almost all protoplanetary discs start their evolution in a strongly self-gravitating state. In agreement with almost all previous work in this area, we conclude that on the scales relevant to planet formation these discs are not gravitationally unstable to gas fragmentation, but instead form strong, transient spiral arms. These spiral arms can act as efficient dust traps allowing the accumulation and subsequent fragmentation of the dust (but not the gas). This phase is likely to populate the disc with relatively large planetesimals on short timescales while the disc is still veiled by a dusty-gas envelope. Crucially, the early formation of large planetesimals overcomes the main barriers remaining within the core accretion model. A prediction of this picture is that essentially all observable protoplanetary discs are already planet hosting.

The Maximum Mass Solar Nebula and the early formation of planets

NASA Astrophysics Data System (ADS)

Nixon, C. J.; King, A. R.; Pringle, J. E.

2018-07-01

Current planet formation theories provide successful frameworks with which to interpret the array of new observational data in this field. However, each of the two main theories (core accretion, gravitational instability) is unable to explain some key aspects. In many planet formation calculations, it is usual to treat the initial properties of the planet-forming disc (mass, radius, etc.) as free parameters. In this paper, we stress the importance of setting the formation of planet-forming discs within the context of the formation of the central stars. By exploring the early stages of disc formation, we introduce the concept of the Maximum Mass Solar Nebula, as opposed to the oft-used minimum mass solar nebula. It is evident that almost all protoplanetary discs start their evolution in a strongly self-gravitating state. In agreement with almost all previous work in this area, we conclude that on the scales relevant to planet formation these discs are not gravitationally unstable to gas fragmentation, but instead form strong, transient spiral arms. These spiral arms can act as efficient dust traps allowing the accumulation and subsequent fragmentation of the dust (but not the gas). This phase is likely to populate the disc with relatively large planetesimals on short time-scales while the disc is still veiled by a dusty-gas envelope. Crucially, the early formation of large planetesimals overcomes the main barriers remaining within the core accretion model. A prediction of this picture is that essentially all observable protoplanetary discs are already planet hosting.

Enhancing Research and Practice in Early Childhood through Formative and Design Experiments

ERIC Educational Resources Information Center

Bradley, Barbara A.; Reinking, David

2011-01-01

This article describes formative and design experiments and how they can advance research and instructional practices in early childhood education. We argue that this relatively new approach to education research closes the gap between research and practice, and it addresses limitations that have been identified in early childhood research. We…

Early Miocene benthic foraminifera and biostratigraphy of the Qom Formation, Deh Namak, Central Iran

NASA Astrophysics Data System (ADS)

Daneshian, Jahanbakhsh; Dana, Leila Ramezani

2007-03-01

A total of 165 samples were collected from the Qom Formation investigated in a stratigraphic section north of Deh Namak, in Central Iran. From these, 35 genera and 47 species of benthic foraminifera were identified. The age of the studied section is Early Miocene (Aquitanian to Early Burdigalian) based on the occurrence of Borelis melo curdica, Meandropsina anahensis, Meandropsina iranica, Elphidium sp. 14, Peneroplis farsensis, and Triloculina tricarinata. The thickness of the Qom Formation is 401 m of which 161.2 m is early Burdigalian in age. Foraminiferal assemblages in the Deh Namak section are referable to the Borelis melo group- Meandropsina iranica Assemblage Zone and Miogypsinoides- Archaias-Valvulinid Assemblage Zone of [Adams, T.D., Bourgeois, F., 1967. Asmari biostratigraphy. Iranian Oil Operating Companies, Geological and Exploration Division, Report1074 (unpublished) 1-37.] described originally from the Asmari Formation.

Early laparotomy wound failure as the mechanism for incisional hernia formation

PubMed Central

Xing, Liyu; Culbertson, Eric J.; Wen, Yuan; Franz, Michael G.

2015-01-01

Background Incisional hernia is the most common complication of abdominal surgery leading to reoperation. In the United States, 200,000 incisional hernia repairs are performed annually, often with significant morbidity. Obesity is increasing the risk of laparotomy wound failure. Methods We used a validated animal model of incisional hernia formation. We intentionally induced laparotomy wound failure in otherwise normal adult, male Sprague-Dawley rats. Radio-opaque, metal surgical clips served as markers for the use of x-ray images to follow the progress of laparotomy wound failure. We confirmed radiographic findings of the time course for mechanical laparotomy wound failure by necropsy. Results Noninvasive radiographic imaging predicts early laparotomy wound failure and incisional hernia formation. We confirmed both transverse and craniocaudad migration of radio-opaque markers at necropsy after 28 d that was uniformly associated with the clinical development of incisional hernias. Conclusions Early laparotomy wound failure is a primary mechanism for incisional hernia formation. A noninvasive radiographic method for studying laparotomy wound healing may help design clinical trials to prevent and treat this common general surgical complication. PMID:23036516

Supersonic gas streams enhance the formation of massive black holes in the early universe.

PubMed

Hirano, Shingo; Hosokawa, Takashi; Yoshida, Naoki; Kuiper, Rolf

2017-09-29

The origin of super-massive black holes in the early universe remains poorly understood. Gravitational collapse of a massive primordial gas cloud is a promising initial process, but theoretical studies have difficulty growing the black hole fast enough. We report numerical simulations of early black hole formation starting from realistic cosmological conditions. Supersonic gas motions left over from the Big Bang prevent early gas cloud formation until rapid gas condensation is triggered in a protogalactic halo. A protostar is formed in the dense, turbulent gas cloud, and it grows by sporadic mass accretion until it acquires 34,000 solar masses. The massive star ends its life with a catastrophic collapse to leave a black hole-a promising seed for the formation of a monstrous black hole. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Critical Thinking about Critical Periods. A Series from the National Center for Early Development and Learning.

ERIC Educational Resources Information Center

Bailey, Donald B., Jr., Ed.; Bruer, John T., Ed.; Symons, Frank J., Ed.; Lichtman, Jeff W., Ed.

The concept of critical or sensitive periods in child development provides an example around which to organize discussion of what is known and not known about brain development and the implications of brain science on early childhood policy and practice. This book reviews the early history of critical periods and evidence for their existence in…

Implications of Martian Phyllosilicate Formation Conditions to the Early Climate on Mars

NASA Astrophysics Data System (ADS)

Bishop, J. L.; Baker, L.; Fairén, A. G.; Michalski, J. R.; Gago-Duport, L.; Velbel, M. A.; Gross, C.; Rampe, E. B.

2017-12-01

We propose that short-term warmer and wetter environments, occurring sporadically in a generally cold early Mars, enabled formation of phyllosilicate-rich outcrops on the surface of Mars without requiring long-term warm and wet conditions. We are investigating phyllosilicate formation mechanisms including CO2 and H2O budgets to provide constraints on the early martian climate. We have evaluated the nature and stratigraphy of phyllosilicate-bearing surface units on Mars based on i) phyllosilicate-forming environments on Earth, ii) phyllosilicate reactions in the lab, and iii) modeling experiments involving phyllosilicates and short-range ordered (SRO) materials. The type of phyllosilicates that form on Mars depends on temperature, water/rock ratio, acidity, salinity and available ions. Mg-rich trioctahedral smectite mixtures are more consistent with subsurface formation environments (crustal, hydrothermal or alkaline lakes) up to 400 °C and are not associated with martian surface environments. In contrast, clay profiles dominated by dioctahedral Al/Fe-smectites are typically formed in subaqueous or subaerial surface environments. We propose models describing formation of smectite-rich outcrops and laterally extensive vertical profiles of Fe/Mg-smectites, sulfates, and Al-rich clay assemblages formed in surface environments. Further, the presence of abundant SRO materials without phyllosilicates could mark the end of the last warm and wet episode on Mars supporting smectite formation. Climate Implications for Early Mars: Clay formation reactions proceed extremely slowly at cool temperatures. The thick smectite outcrops observed on Mars through remote sensing would require standing water on Mars for hundreds of millions of years if they formed in waters 10-15 °C. However, warmer temperatures could have enabled faster production of these smectite-rich beds. Sporadic warming episodes to 30-40 °C could have enabled formation of these smectites over only tens or

Characteristics and formation mechanism for stainless steel fiber with periodic micro-fins

NASA Astrophysics Data System (ADS)

Tang, Tao; Wan, Zhenping; Lu, Longsheng; Tang, Yong

2016-05-01

Metal fibers have been widely used in many industrial applications due to their unique advantages. In certain applications, such as catalyst supports or orthopedic implants, a rough surface or tiny outshoots on the surface of metal fibers to increase surface area are needed. However, it has not been concerned about the surface morphologies of metal fiber in the current research of metal fiber manufacturing. In this paper, a special multi-tooth tool composed of a row of triangular tiny teeth is designed. The entire cutting layer of multi-tooth tool bifurcates into several thin cutting layers due to tiny teeth involved in cutting. As a result, several stainless steel fibers with periodic micro-fins are produced simultaneously. Morphology of periodic micro-fins is found to be diverse and can be classified into three categories: unilateral plane, unilateral tapering and bilateral. There are two forming mechanisms for the micro-fins. One is that periodic burrs remained on the free side of cutting layer of a tiny tooth create micro-fins of stainless steel fiber produced by the next neighboring tiny tooth; the other is that the connections between two fibers stuck together come to be micro-fins if the two fibers are finally detached. Influence of cutting conditions on formation of micro-fins is investigated. Experimental results show that cutting depth has no significant effect on micro-fin formation, high cutting speed is conducive to micro-fin formation, and feed should be between 0.12 mm/r and 0.2 mm/r to reliably obtain stainless steel fiber with micro-fins. This research presents a new pattern of stainless steel fiber characterized by periodic micro-fins formed on the edge of fiber and its manufacturing method.

Early Family Formation among White, Black, and Mexican American Women

ERIC Educational Resources Information Center

Landale, Nancy S.; Schoen, Robert; Daniels, Kimberly

2010-01-01

Using data from Waves I and III of Add Health, this study examines early family formation among 6,144 White, Black, and Mexican American women. Drawing on cultural and structural perspectives, models of the first and second family transitions (cohabitation, marriage, or childbearing) are estimated using discrete-time multinomial logistic…

Do mature forest birds prefer early-successional habitat during the post-fledging period?

Treesearch

Carlin C. Chandler; David I. King; Richard B. Chandler

2012-01-01

Recent studies have highlighted the importance of the post-fledging period to bird populations, suggesting that the importance of this portion of the life cycle is equal to or greater than the nesting period. Nevertheless, few studies have compared abundance of forest nesting species between mature forest and early-successional habitats while controlling for...

Early episodes of high-pressure core formation preserved in plume mantle

NASA Astrophysics Data System (ADS)

Jackson, Colin R. M.; Bennett, Neil R.; Du, Zhixue; Cottrell, Elizabeth; Fei, Yingwei

2018-01-01

The decay of short-lived iodine (I) and plutonium (Pu) results in xenon (Xe) isotopic anomalies in the mantle that record Earth’s earliest stages of formation. Xe isotopic anomalies have been linked to degassing during accretion, but degassing alone cannot account for the co-occurrence of Xe and tungsten (W) isotopic heterogeneity in plume-derived basalts and their long-term preservation in the mantle. Here we describe measurements of I partitioning between liquid Fe alloys and liquid silicates at high pressure and temperature and propose that Xe isotopic anomalies found in modern plume rocks (that is, rocks with elevated 3He/4He ratios) result from I/Pu fractionations during early, high-pressure episodes of core formation. Our measurements demonstrate that I becomes progressively more siderophile as pressure increases, so that portions of mantle that experienced high-pressure core formation will have large I/Pu depletions not related to volatility. These portions of mantle could be the source of Xe and W anomalies observed in modern plume-derived basalts. Portions of mantle involved in early high-pressure core formation would also be rich in FeO, and hence denser than ambient mantle. This would aid the long-term preservation of these mantle portions, and potentially points to their modern manifestation within seismically slow, deep mantle reservoirs with high 3He/4He ratios.

Social Class, Family Formation, and Delinquency in Early Adulthood

PubMed Central

Kuhl, Danielle C.; Chavez, Jorge M.; Swisher, Raymond R.; Wilczak, Andrew

2015-01-01

Recent research suggests increasing heterogeneity in the transition from adolescence to early adulthood. This study considers how this heterogeneity may influence delinquency between these two developmental periods. We focus on the role of family transitions, educational attainment, and employment in predicting risk of nonviolent delinquency and substance use, as well as disparities in transitions across socioeconomic status subgroups. Data are from the National Longitudinal Study of Adolescent to Adult Health (Add Health). We find that family and neighborhood advantage are negatively associated with transitions into marriage, cohabitation, and parenthood, yet positively associated with educational attainment. In addition, adolescent family and neighborhood advantage are associated with a continuation of delinquent behavior and substance use during early adulthood. In multivariate analyses, accounting for family transitions in early adulthood largely attenuates the relationship between neighborhood advantage in adolescence and delinquency in early adulthood. We conclude by discussing the implications of our findings for developmental criminology. PMID:27418713

Germ layer differentiation during early hindgut and cloaca formation in rabbit and pig embryos

PubMed Central

Hassoun, Romia; Schwartz, Peter; Rath, Detlef; Viebahn, Christoph; Männer, Jörg

2010-01-01

Relative to recent advances in understanding molecular requirements for endoderm differentiation, the dynamics of germ layer morphology and the topographical distribution of molecular factors involved in endoderm formation at the caudal pole of the embryonic disc are still poorly defined. To discover common principles of mammalian germ layer development, pig and rabbit embryos at late gastrulation and early neurulation stages were analysed as species with a human-like embryonic disc morphology, using correlative light and electron microscopy. Close intercellular contact but no direct structural evidence of endoderm formation such as mesenchymal–epithelial transition between posterior primitive streak mesoderm and the emerging posterior endoderm were found. However, a two-step process closely related to posterior germ layer differentiation emerged for the formation of the cloacal membrane: (i) a continuous mesoderm layer and numerous patches of electron-dense flocculent extracellular matrix mark the prospective region of cloacal membrane formation; and (ii) mesoderm cells and all extracellular matrix including the basement membrane are lost locally and close intercellular contact between the endoderm and ectoderm is established. The latter process involves single cells at first and then gradually spreads to form a longitudinally oriented seam-like cloacal membrane. These gradual changes were found from gastrulation to early somite stages in the pig, whereas they were found from early somite to mid-somite stages in the rabbit; in both species cloacal membrane formation is complete prior to secondary neurulation. The results highlight the structural requirements for endoderm formation during development of the hindgut and suggest new mechanisms for the pathogenesis of common urogenital and anorectal malformations. PMID:20874819

Milankovitch and sub-Milankovitch cycles of the Early Triassic Daye Formation, South China and their geochronological and paleoclimatic implications

NASA Astrophysics Data System (ADS)

Wu, H.; Zhang, S.; Feng, Q.; Jiang, G.; Li, H.; Yang, T.

2011-12-01

The most profound mass extinction in the Phanerozoic occurred at the end of the Permian, with global loss of nearly 90% of marine invertebrate species and 70% of terrestrial vertebrate genera. Recent studies suggested that volcanisms represented by the Siberian Trap were most likely cause of the end-Permian extinction. The post-extinction periods in the Early Triassic was characterized by low biodiversity, reduced abundance and size of invertebrates, hiatus in coal deposition, anomalously high sediment fluxes, and large perturbations of the carbon cycle, which have been interpreted as the consequence of persistently unfavorable environmental conditions. However, the time framework for the Early Triassic geological, biological and geochemical events is traditionally established by conodont biostratigraphy, but the absolute duration of condont biozones are not well constrained. In this study, a rock magnetic cyclostratigraphy, based on high-resolution analysis (2440 samples) of magnetic susceptibility (MS) and anhysteretic remanent magnetization (ARM) intensity variations, was developed for the 55.1-m-thick, Early Triassic Daye Formation at the Daxiakou section, Hubei province in South China. The Daye Formation shows exceptionally well-preserved lithological cycles with alternations of thin-bedded mudstone, marl and limestone, which are closely tracked by the MS and ARM variations. Power spectral, wavelet and amplitude modulation (AM) analysis of the ARM and MS series reveal strong evidence for the presence of Milankovitch to sub-Milankovitch frequencies dominated by precession index signal and 4-5 ka cycles. Cycles expressed by variations in MS and ARM were likely controlled by the input of fine-grained detrital magnetite, which in turn may be driven by astronomically induced changes in monsoon intensity in the equatorial eastern Tethys during the Early Triassic greenhouse period. On the basis of the 100-ka tuning results, the astronomically constrained duration of

PITX2 and NODAL expression during axis formation in the early rabbit embryo.

PubMed

Plöger, Ruben; Viebahn, Christoph

2018-04-26

Attaining molecular and morphological axial polarity during gastrulation is a fundamental early requirement for normal development of the embryo. In mammals, the first morphological sign of the anterior-posterior axis appears anteriorly in the form of the anterior marginal crescent (or anterior visceral endoderm) while in the avian the first such sign is the Koller's sickle at the posterior pole of the embryonic disc. Despite this inverse mode of axis formation many genes and molecular pathways involved in various steps of this process seem to be evolutionary conserved amongst amniotes, the nodal gene being a well-known example with its functional involvement prior and during gastrulation. The pitx2 gene, however, is a new candidate described in the chick as an early marker for anterior-posterior polarity and as regulator of axis formation including twinning. To find out whether pitx2 has retained its inductive and early marker function during the evolution of mammals, this study analyzes pitx2 and nodal expression at parallel stages during formation of the anterior-posterior polarity in the early rabbit embryo using whole-mount in situ hybridization and serial light-microscopical sections. At a late pre-gastrulation stage a localized reduction of nodal expression presages the position of the anterior pole of the embryonic disc and thus serves as the earliest molecular marker of anterior-posterior polarity known so far. pitx2 is expressed in a polarized manner in the anterior marginal crescent and in the posterior half of the embryonic disc during further development only while nodal expression in the anterior segment of the posterior pitx2 expression domain helps to define the so-called anterior streak domain (ASD), a novel progenitor region of the anterior half of the primitive streak. The expression patterns of both genes thus serve as signs of a conserved involvement in early axis formation in amniotes and, possibly, in twinning in mammals as well. Copyright �

Early archosauromorph remains from the Permo-Triassic Buena Vista Formation of north-eastern Uruguay

PubMed Central

Velozo, Pablo; Meneghel, Melitta; Piñeiro, Graciela

2015-01-01

The Permo-Triassic archosauromorph record is crucial to understand the impact of the Permo-Triassic mass extinction on the early evolution of the group and its subsequent dominance in Mesozoic terrestrial ecosystems. However, the Permo-Triassic archosauromorph record is still very poor in most continents and hampers the identification of global macroevolutionary patterns. Here we describe cranial and postcranial bones from the Permo-Triassic Buena Vista Formation of northeastern Uruguay that contribute to increase the meagre early archosauromorph record from South America. A basioccipital fused to both partial exoccipitals and three cervical vertebrae are assigned to Archosauromorpha based on apomorphies or a unique combination of characters. The archosauromorph remains of the Buena Vista Formation probably represent a multi-taxonomic assemblage composed of non-archosauriform archosauromorphs and a ‘proterosuchid-grade’ animal. This assemblage does not contribute in the discussion of a Late Permian or Early Triassic age for the Buena Vista Formation, but reinforces the broad palaeobiogeographic distribution of ‘proterosuchid grade’ diapsids in Permo-Triassic beds worldwide. PMID:25737816

Early type galaxies: Mapping out the two-dimensional space of galaxy star formation histories

NASA Astrophysics Data System (ADS)

Graves, Genevieve J.

Early type galaxies form a multi-parameter family, as evidenced by the two- dimensional (2-D) Fundamental Plane relationship. However, their star formation histories are often treated as a one-dimensional mass sequence. This dissertation presents a systematic study of the relationship between the multi- parameter structural properties of early type galaxies and their star formation histoires. We demonstrate that the stellar populations of early type galaxies span a 2-D space, which means that their star formation histories form a two- parameter family. This 2-D family is then mapped onto several familiar early type galaxy scaling relations, including the color-magnitude relation, the Fundamental Plane, and a cross-section through the Fundamental Plane. We find that the stellar population properties, and therefore the star formation histories of early type galaxies depend most strongly on galaxy velocity dispersion (s), rather than on luminosity ( L ), stellar mass ( M [low *] ), or dynamical mass ( M dyn ). Interestingly, stellar populations are independent of the radius ( R e ) of the galaxies. At fixed s, they show correlated residuals through the thickness of the Fundamental Plane (FP) in the surface-brightness ( I e ) dimension, such that low-surface-brightness galaxies are older, less metal-enriched, and more enhanced in Mg relative to Fe than their counterparts at the same s and R e on the FP midplane. Similarly, high- surface-brightness galaxies are younger, more metal-rich, and less Mg-enhanced than their counterparts on the FP midplane. These differences suggest that the duration of star formation varies through the thickness of the FP. If the dynamical mass-to-light ratios of early type galaxies ( M dyn /L ) were constant for all such galaxies, the FP would be equivalent to the plane predicted by the virial relation. However, the observed FP does not exactly match the virial plane. The FP is tilted from the virial plane, indicating that M dyn /L varies

Exploring simulated early star formation in the context of the ultrafaint dwarf galaxies

NASA Astrophysics Data System (ADS)

Corlies, Lauren; Johnston, Kathryn V.; Wise, John H.

2018-04-01

Ultrafaint dwarf galaxies (UFDs) are typically assumed to have simple, stellar populations with star formation ending at reionization. Yet as the observations of these galaxies continue to improve, their star formation histories (SFHs) are revealed to be more complicated than previously thought. In this paper, we study how star formation, chemical enrichment, and mixing proceed in small, dark matter haloes at early times using a high-resolution, cosmological, hydrodynamical simulation. The goals are to inform the future use of analytic models and to explore observable properties of the simulated haloes in the context of UFD data. Specifically, we look at analytic approaches that might inform metal enrichment within and beyond small galaxies in the early Universe. We find that simple assumptions for modelling the extent of supernova-driven winds agree with the simulation on average, whereas inhomogeneous mixing and gas flows have a large effect on the spread in simulated stellar metallicities. In the context of the UFDs, this work demonstrates that simulations can form haloes with a complex SFH and a large spread in the metallicity distribution function within a few hundred Myr in the early Universe. In particular, bursty and continuous star formation are seen in the simulation and both scenarios have been argued from the data. Spreads in the simulated metallicities, however, remain too narrow and too metal-rich when compared to the UFDs. Future work is needed to help reduce these discrepancies and advance our interpretation of the data.

The Formation of Fe/Mg Smectite Under Mildly Acidic Conditions on Early Mars

NASA Technical Reports Server (NTRS)

Sutter, Brad; Golden, D. C.; Ming, Douglas W.; Niles, P. B.

2011-01-01

The detection of Fe/Mg smectites and carbonate in Noachian and early Hesperian terrain of Mars has been used to suggest that neutral to mildly alkaline conditions prevailed during the early history of Mars. However, if early Mars was neutral to moderately alkaline with a denser CO2 atmosphere than today, then large carbonates deposits should be more widely detected in Noachian terrain. The critical question is: Why have so few carbonate deposits been detected compared to Fe/Mg smectites? We suggest that Fe/Mg smectites on early Mars formed under mildly acidic conditions, which would inhibit the extensive formation of carbonate deposits. The goal of this work is to evaluate the formation of Fe/Mg smectites under mildly acidic conditions. The stability of smectites under mildly acidic conditions is attributed to elevated Fe/Mg activities that inhibit smectite dissolution. Beidelite and saponite have been shown to form from hydrothermal alteration of basaltic glass at pH 3.5-4.0 in seawater solutions. Nontronite is also known to be stable in mildly acidic systems associated with mafic and ultramafic rock. Nontronite was shown to form in acid sulfate soils in the Bangkok Plain, Thailand due to oxidation of Fe-sulfides that transformed saponite to nontronite. Smectite is known to transform to kaolinite in naturally acid soils due to selective leaching of Mg. However, if Mg removal is limited, then based on equilibrium relationships, the dissolution of smectite should be minimized. If Fe and Mg solution activities are sufficiently high, such as might be found in a low water/rock ratio system that is poorly drained, smectite could form and remain stable under mildly acidic conditions on Mars. The sources of mild acidity on early Mars includes elevated atmospheric CO2 levels, Fe-hydrolysis reactions, and the presence of volcanic SO2 aerosols. Equilibrium calculations dictate that water equilibrated with an early Mars CO2 atmosphere at 1 to 4 bar yields a pH of 3.6 to 3

Modelling periodic structure formation on 100Cr6 steel after irradiation with femtosecond-pulsed laser beams

NASA Astrophysics Data System (ADS)

Tsibidis, George D.; Mimidis, Alexandros; Skoulas, Evangelos; Kirner, Sabrina V.; Krüger, Jörg; Bonse, Jörn; Stratakis, Emmanuel

2018-01-01

We investigate the periodic structure formation upon intense femtosecond pulsed irradiation of chrome steel (100Cr6) for linearly polarised laser beams. The underlying physical mechanism of the laser-induced periodic structures is explored, their spatial frequency is calculated and theoretical results are compared with experimental observations. The proposed theoretical model comprises estimations of electron excitation, heat transfer, relaxation processes, and hydrodynamics-related mass transport. Simulations describe the sequential formation of sub-wavelength ripples and supra-wavelength grooves. In addition, the influence of the laser wavelength on the periodicity of the structures is discussed. The proposed theoretical investigation offers a systematic methodology towards laser processing of steel surfaces with important applications.

Early Mesozoic history and petroleum potential of formations in Wyoming and northern Utah

DOE Office of Scientific and Technical Information (OSTI.GOV)

Picard, M.D.

1993-08-01

During the Triassic and Jurassic, over what is now Wyoming and northern Utah, roughly equal amounts of sediment were being deposited in continental settings-lake, stream, and eolian-and in shallow-marine or deltaic-plain settings-delta, beach, marsh, tidal flat, and shallow shelf. Clastic rocks dominate. In order of decreasing abundance, the rocks are fine-grained clastics (siltstone, claystone, mudstone), sandstone, carbonates, evaporites, and claystone- and carbonate-pebble conglomerate. Approximately four-fifths of the succession contains red beds or variegated layers-purple, maroon, lavender, olive, green. Unconformities bound Jurassic formations in Wyoming-Nugget, Gypsum Spring, Sundance, and Morrison. Unconformities also bound the continental Upper Triassic section-unnamed red bed unit,more » Jelm, Popo Agie-separating it from the underlying shallow-marine formations-Dinwoody, Red Peak, Alcova, Crow Mountain. Within the marine sequence, an unconformity occurs at the top of the Alcova and, quite likely, shorter periods of erosion took place at the top and below the base of the sandy faces that underlies the Alcova. The postulate duration of the principal unconformities totals about 18 m.y., at least one-sixth of early Mesozoic time. The bulk of the remaining 80-100 m.y. may be represented by a large number of smaller unconformities. For the lower Mesozoic, as for most stratigraphic intervals, a few beds contain the story of what has taken place during the abyss of geologic time. Like other places in the world where evaporites occur in the Triassic, the Wyoming section produces little crude oil. No significant sequence in the early Mesozoic shows source-bed characteristics. The Crow Mountain Sandstone contains the best reservoirs. The Lower( ) Jurassic Nugget Sandstone produces the most oil and gas in the thrust belt of southwestern Wyoming and northern Utah. Cretaceous claystones below the thrusts contain the source beds.« less

Core formation, wet early mantle, and H2O degassing on early Mars

NASA Technical Reports Server (NTRS)

Kuramoto, K.; Matsui, T.

1993-01-01

Geophysical and geochemical observations strongly suggest a 'hot origin of Mars,' i.e., the early formation of both the core and the crust-mantle system either during or just after planetary accretion. To consider the behavior of H2O in the planetary interior it is specifically important to determine by what mechanism the planet is heated enough to cause melting. For Mars, the main heat source is probably accretional heating. Because Mars is small, the accretion energy needs to be effectively retained in its interior. Therefore, the three candidates of heat retention mechanism are discussed first: (1) the blanketing effect of the primordial H2-He atmosphere; (2) the blanketing effect of the impact-induced H2O-CO2 atmosphere; and (3) the higher deposition efficiency of impact energy due to larger impacts. It was concluded that (3) the is the most plausible mechanism for Mars. Then, its possible consequence on how wet the early martian mantle was is discussed.

Apoptosis in Early Salivary Gland Duct Morphogenesis and Lumen Formation.

PubMed

Teshima, T H N; Wells, K L; Lourenço, S V; Tucker, A S

2016-03-01

Salivary glands are essential for the maintenance of oral health by providing lubrication and antimicrobial protection to the mucosal and tooth surfaces. Saliva is modified and delivered to the oral cavity by a complex multifunctional ductal system. During development, these ducts form as solid tubes, which undergo cavitation to create lumens. Apoptosis has been suggested to play a role in this cavitation process along with changes in cell polarity. Here, we show that apoptosis occurs from the very earliest stages of mouse salivary gland development, much earlier than previously reported. Apoptotic cells were observed in the center of the first epithelial stalk at early-stage embryonic day 12.5 (E12.5) according to both TUNEL staining and cleaved caspase 3 immunofluorescence. The presumptive lumen space was highlighted by the colocalization of a predictive lumen marker, cytokeratin 7. At E14.5, as lumens start to form throughout the glands, apoptotic expression decreased while cytokeratin 7 remained positive. In vitro inhibition of all caspases in E12.5 and E13.5 salivary glands resulted in wider ducts, as compared with the controls, and a defect in lumen formation. In contrast, no such defect in lumen formation was observed at E14.5. Our data indicate that apoptosis is involved during early stages of gland formation (E12.5 onward) and appears important for shaping the forming ducts. © International & American Associations for Dental Research 2015.

Epicatechin, a component of dark chocolate, enhances memory formation if applied during the memory consolidation period.

PubMed

Fernell, Maria; Swinton, Cayley; Lukowiak, Ken

2016-01-01

Epicatechin (Epi), a flavanol found in foods such as dark chocolate has previously been shown to enhance memory formation in our model system, operant conditioning of aerial respiration in Lymnaea. In those experiments snails were trained in Epi. Here we ask whether snails exposed to Epi before training, during the consolidation period immediately following training, or 1 h after training would enhance memory formation. We report here that Epi is only able to enhance memory if snails are placed in Epi-containing pond water immediately after training. That is, Epi enhances memory formation if it is applied during the memory consolidation period as well as if snails are trained in Epi-containing pond water.

Epicatechin, a component of dark chocolate, enhances memory formation if applied during the memory consolidation period

PubMed Central

Fernell, Maria; Swinton, Cayley; Lukowiak, Ken

2016-01-01

ABSTRACT Epicatechin (Epi), a flavanol found in foods such as dark chocolate has previously been shown to enhance memory formation in our model system, operant conditioning of aerial respiration in Lymnaea. In those experiments snails were trained in Epi. Here we ask whether snails exposed to Epi before training, during the consolidation period immediately following training, or 1 h after training would enhance memory formation. We report here that Epi is only able to enhance memory if snails are placed in Epi-containing pond water immediately after training. That is, Epi enhances memory formation if it is applied during the memory consolidation period as well as if snails are trained in Epi-containing pond water. PMID:27574544

On the role of extracellular polymeric substances during early stages of Xylella fastidiosa biofilm formation.

PubMed

Lorite, Gabriela S; de Souza, Alessandra A; Neubauer, Daniel; Mizaikoff, Boris; Kranz, Christine; Cotta, Mônica A

2013-02-01

The structural integrity and protection of bacterial biofilms are intrinsically associated with a matrix of extracellular polymeric substances (EPS) produced by the bacteria cells. However, the role of these substances during biofilm adhesion to a surface remains largely unclear. In this study, the influence of EPS on Xylella fastidiosa biofilm formation was investigated. This bacterium is associated with economically important plant diseases; it presents a slow growth rate and thus allows us to pinpoint more precisely the early stages of cell-surface adhesion. Scanning electron microscopy and atomic force microscopy show evidence of EPS production in such early stages and around individual bacteria cells attached to the substrate surface even a few hours after inoculation. In addition, EPS formation was investigated via attenuated total reflectance (ATR) Fourier transform infrared spectroscopy (FTIR). To this end, X. fastidiosa cells were inoculated within an ATR liquid cell assembly. IR-ATR spectra clearly reveal EPS formation already during the early stages of X. fastidiosa biofilm formation, thereby providing supporting evidence for the hypothesis of the relevance of the EPS contribution to the adhesion process. Copyright © 2012 Elsevier B.V. All rights reserved.

The paredon, Mexico, obsidian source and early formative exchange.

PubMed

Charlton, T H; Grove, D C; Hopke, P K

1978-09-01

In 1975, archeological surface surveys of trade routes located again a pre-Hispanic obsidian source in central Mexico first reported in 1902. Initial trace element studies of the Paredón source through an analysis by neutron activation have been compared with similar studies of the obsidian found at Chalcatzingo 150 kilometers from the source. These comparisons indicate that obsidian from Paredón, rather than Otumba, was of primary importance during the Early Formative in central Mexico.

A Multi-Faceted Study of Three Forms of Galactic Formation in the Early Universe

NASA Astrophysics Data System (ADS)

Jones, Gareth Christopher

While observations of the early universe have focused on bright, highly starbursting galaxies, star formation activity in the early universe was dominated by main sequence galaxies. Observations of the former group have been accumulating for decades, but the latter are only recently observable using modern instruments. In this work, we apply the Very Large Array (VLA) and the Atacama Large Millimeter/submillimeter Array (ALMA) to observe specific examples of each galactic class, in order to explore three modes of galaxy formation: smooth accretion, satellite accretion, and massive mergers. Using the molecular gas tracer CO and a broad set of continuum measurements, we characterize the gas mass and distribution, star formation, and dust temperature of the two archetypal massively merging Hyper-Luminous IR Galaxies (HyLIRGs) BRI1202-0725 & BRI1335-0417. We then examine the [C II] emission of the Lyman-Break Galaxy (LBG) WMH5, which shows two infalling gas clouds, implying ongoing formation via filamentary accretion. Finally, we apply a classical suite of dynamical characterization tools to [C II] observations of three MS galaxies and three starbursts, resulting in rotation curves and dynamical masses for each. By examining each of these sources in detail, we find that galaxies in the early (i.e., z > 4) universe formed via a broad range of interactions, ranging from cold-mode accretion to major mergers. As these instruments continue observing, and with the future advent of JWST and perhaps the ngVLA, stronger constraints may be placed on the behavior of the galaxies in the epoch of initial galaxy formation.

Characteristics of microbial community involved in early biofilms formation under the influence of wastewater treatment plant effluent.

PubMed

Peng, Yuke; Li, Jie; Lu, Junling; Xiao, Lin; Yang, Liuyan

2018-04-01

Effluents from wastewater treatment plants (WWTPs) containing microorganisms and residual nutrients can influence the biofilm formation. Although the process and mechanism of bacterial biofilm formation have been well characterized, little is known about the characteristics and interaction of bacteria, archaea and eukaryotes in the early colonization, especially under the influence of WWTP effluent. The aim of this study was to characterize the important bacterial, archaeal and eukaryotic species in the early stage of biofilm formation downstream of the WWTP outlet. Water and biofilm samples were collected 24 and 48hr after the deposition of bio-cords in the stream. Illumina Miseq sequencing of the 16S and 18S rDNA showed that, among the three domains, the bacterial biofilm community had the largest alpha and beta diversity. The early bacterial colonizers appeared to be "biofilm-specific", with only a few dominant operational taxonomic units (OTUs) shared between the biofilm and the ambient water environment. Alpha-proteobacteria and Ciliophora tended to dominate the bacterial and eukaryotic communities, respectively, of the early biofilm already at 24hr, whereas archaea played only a minor role during the early stage of colonization. The network analysis showed that the three domains of microbial community connected highly during the early colonization and it might be a characteristic of the microbial communities in the biofilm formation process where co-occurrence relationships could drive coexistence and diversity maintenance within the microbial communities. Copyright © 2017. Published by Elsevier B.V.

Early Seizures Prematurely Unsilence Auditory Synapses to Disrupt Thalamocortical Critical Period Plasticity.

PubMed

Sun, Hongyu; Takesian, Anne E; Wang, Ting Ting; Lippman-Bell, Jocelyn J; Hensch, Takao K; Jensen, Frances E

2018-05-29

Heightened neural excitability in infancy and childhood results in increased susceptibility to seizures. Such early-life seizures are associated with language deficits and autism that can result from aberrant development of the auditory cortex. Here, we show that early-life seizures disrupt a critical period (CP) for tonotopic map plasticity in primary auditory cortex (A1). We show that this CP is characterized by a prevalence of "silent," NMDA-receptor (NMDAR)-only, glutamate receptor synapses in auditory cortex that become "unsilenced" due to activity-dependent AMPA receptor (AMPAR) insertion. Induction of seizures prior to this CP occludes tonotopic map plasticity by prematurely unsilencing NMDAR-only synapses. Further, brief treatment with the AMPAR antagonist NBQX following seizures, prior to the CP, prevents synapse unsilencing and permits subsequent A1 plasticity. These findings reveal that early-life seizures modify CP regulators and suggest that therapeutic targets for early post-seizure treatment can rescue CP plasticity. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Periodic Vesicle Formation in Tectonic Fault Zones--an Ideal Scenario for Molecular Evolution.

PubMed

Mayer, Christian; Schreiber, Ulrich; Dávila, María J

2015-06-01

Tectonic fault systems in the continental crust offer huge networks of interconnected channels and cavities. Filled mainly with water and carbon dioxide (CO2), containing a wide variety of hydrothermal chemistry and numerous catalytic surfaces, they may offer ideal reaction conditions for prebiotic chemistry. In these systems, an accumulation zone for organic compounds will develop at a depth of approximately 1 km where CO2 turns sub-critical and dissolved components precipitate. At this point, periodic pressure changes caused for example by tidal influences or geyser activity may generate a cyclic process involving repeated phase transitions of carbon dioxide. In the presence of amphiphilic compounds, this will necessarily lead to the transient formation of coated water droplets in the gas phase and corresponding vesicular structures in the aqueous environment. During this process, the concentration of organic components inside the droplets and vesicles would be drastically increased, allowing for favorable reaction conditions and, in case of the vesicles generated, large trans-membrane concentration gradients. Altogether, the process of periodic formation and destruction of vesicles could offer a perfect environment for molecular evolution in small compartments and for the generation of protocells. The basic process of vesicle formation is reproduced experimentally with a lipid in a water/CO2 system.

Influence of periodic orbits on the formation of giant planetary systems

NASA Astrophysics Data System (ADS)

Libert, Anne-Sophie; Sotiriadis, Sotiris; Antoniadou, Kyriaki I.

2018-02-01

The late-stage formation of giant planetary systems is rich in interesting dynamical mechanisms. Previous simulations of three giant planets initially on quasi-circular and quasi-coplanar orbits in the gas disc have shown that highly mutually inclined configurations can be formed, despite the strong eccentricity and inclination damping exerted by the disc. Much attention has been directed to inclination-type resonance, asking for large eccentricities to be acquired during the migration of the planets. Here we show that inclination excitation is also present at small to moderate eccentricities in two-planet systems that have previously experienced an ejection or a merging and are close to resonant commensurabilities at the end of the gas phase. We perform a dynamical analysis of these planetary systems, guided by the computation of planar families of periodic orbits and the bifurcation of families of spatial periodic orbits. We show that inclination excitation at small to moderate eccentricities can be produced by (temporary) capture in inclination-type resonance and the possible proximity of the non-coplanar systems to spatial periodic orbits contributes to maintaining their mutual inclination over long periods of time.

Early Paleozoic subduction initiation volcanism of the Iwatsubodani Formation, Hida Gaien belt, Southwest Japan

NASA Astrophysics Data System (ADS)

Tsukada, Kazuhiro; Yamamoto, Koshi; Gantumur, Onon; Nuramkhaan, Manchuk

2017-06-01

In placing Japanese tectonics in an Asian context, variation in the Paleozoic geological environment is a significant issue. This paper investigates the geochemistry of the lower Paleozoic basalt formation (Iwatsubodani Formation) in the Hida Gaien belt, Japan, to consider its tectonic setting. This formation includes the following two types of rock in ascending order: basalt A with sub-ophitic texture and basalt B with porphyritic texture. Basalt A has a high and uniform FeO*/MgO ratio, moderate TiO2, high V, and low Ti/V. The HFSE and REE are nearly the same as those in MORB, and all the data points to basalt A being the "MORB-like fore-arc tholeiitic basalt (FAB)" reported, for example, from the Izu-Bonin-Mariana arc. By contrast, basalt B has a low FeO*/MgO ratio, low TiO2, and low V and Ti/V. It has an LREE-enriched trend and a distinct negative Nb anomaly in the MORB-normalized multi-element pattern and a moderately high LREE/HREE. All these factors suggest that basalt B is calc-alkaline basalt. It is known that FAB is erupted at the earliest stage of arc formation—namely, subduction initiation—and that boninitic/tholeiitic/calc-alkaline volcanism follows at the supra-subduction zone (SSZ). Thus, the occurrence of basalts A (FAB) and B (calc-alkaline rock) is strong evidence of early Paleozoic arc-formation initiation at an SSZ. Evidence for an early Paleozoic SSZ arc is also recognized from the Oeyama, Hayachine-Miyamori, and Sergeevka ophiolites. Hence, both these ophiolites and the Iwatsubodani Formation probably coexisted in a primitive SSZ system in the early Paleozoic.

Molar tooth structures in calcareous nodules, early Neoproterozoic Burovaya Formation, Turukhansk region, Siberia

NASA Astrophysics Data System (ADS)

Pope, Michael C.; Bartley, Julie K.; Knoll, Andrew H.; Petrov, Peter Yu.

2003-05-01

Molar tooth structures are abundant in large (1-2 m diameter) carbonate nodules within fine-grained, subtidal carbonates of the early Neoproterozoic (lower Upper Riphean) Burovaya Formation along the Sukhaya Tunguska River, Turukhansk Uplift, northwestern Siberia. Although molar tooth structures are regionally abundant in this unit, here they occur only within the nodules. Stable isotopic compositions of molar-tooth-filling dolomicrospar cements and of thinly bedded dolomicrite within and surrounding the nodules are indistinguishable from one another. The carbon isotopic compositions (mean δ13C=+2.8‰ PDB±0.4) reflect mean average oceanic surface water composition during their formation; the light oxygen isotopic compositions (mean δ18O=-6.4‰ PDB±2.2) are generally similar to those of other little-altered Meso- to Neoproterozoic limestones and dolostones. These molar tooth structures have no features that would support a tectonic origin; they more likely formed through bacterial processes. Carbonate cement filling of these voids occurred soon after their formation, but the mechanism responsible for this carbonate precipitation is currently uncertain. Local restriction of molar tooth structures to early diagenetic nodules suggests that penecontemporaneous lithification was required for the formation, or at least preservation, of these widespread Mesoproterozoic to Neoproterozoic features.

An experimental flow-through assessment of acidic Fe/Mg smectite formation on early Mars

NASA Astrophysics Data System (ADS)

Sutter, B.; Peretyazhko, T.; Garcia, A. H.; Ming, D. W.

2017-12-01

Orbital observations have detected the phyllosilicate smectite in layered material hundreds of meters thick, intracrater depositional fans, and plains sediments on Mars; however, the detection of carbonate deposits is limited. Instead of neutral/alkaline conditions during the Noachian, early Mars may have experienced mildly acidic conditions derived from volcanic acid-sulfate solutions that allowed Fe/Mg smectite formation but prevented widespread carbonate formation. The detection of acid sulfates (e.g., jarosite) associated with smectite in Mawrth Vallis supports this hypothesis. Previous work demonstrated smectite (saponite) formation in closed hydrologic systems (batch reactor) from basaltic glass at pH 4 and 200°C (Peretyazhko et al., 2016 GCA). This work presents results from alteration of basaltic glass from alkaline to acidic conditions in open hydrologic systems (flow-through reactor). Preliminary experiments exposed basaltic glass to deionized water at 190°C at 0.25 ml/min where solution pH equilibrated to 9.5. These initial high pH experiments were conducted to evaluate the flow-through reactor system before working with lower pHs. Smectite at this pH was not produced and instead X-ray diffraction results consistent with serpentine was detected. Experiments are in progress exposing basaltic glass from pH 8 down to pH 3 to determine what range of pHs could allow for smectite formation in this experimental open-system. The production of smectite under an experimental open-system at low pHs if successful, would support a significant paradigm shift regarding the geochemical evolution of early Mars: Early Mars geochemical solutions were mildly acidic, not neutral/alkaline. This could have profound implications regarding early martain microbiology where acid conditions instead of neutral/alkaline conditions will require further research in terrestrial analogs to address the potential for biosignature preservation on Mars (Johnson et al., 2016, LPSC).

Estimating formation properties from early-time oscillatory water levels in a pumped well

USGS Publications Warehouse

Shapiro, A.M.; Oki, D.S.

2000-01-01

Hydrologists often attempt to estimate formation properties from aquifer tests for which only the hydraulic responses in a pumped well are available. Borehole storage, turbulent head losses, and borehole skin, however, can mask the hydraulic behavior of the formation inferred from the water level in the pumped well. Also, in highly permeable formations or in formations at significant depth below land surface, where there is a long column of water in the well casing, oscillatory water levels may arise during the onset of pumping to further mask formation responses in the pumped well. Usually borehole phenomena are confined to the early stages of pumping or recovery, and late-time hydraulic data can be used to estimate formation properties. In many instances, however, early-time hydraulic data provide valuable information about the formation, especially if there are interferences in the late-time data. A mathematical model and its Laplace transform solution that account for inertial influences and turbulent head losses during pumping is developed for the coupled response between the pumped borehole and the formation. The formation is assumed to be homogeneous, isotropic, of infinite areal extent, and uniform thickness, with leakage from an overlying aquifer, and the screened or open interval of the pumped well is assumed to fully penetrate the pumped aquifer. Other mathematical models of aquifer flow can also be coupled with the equations describing turbulent head losses and the inertial effects on the water column in the pumped well. The mathematical model developed in this paper is sufficiently general to consider both underdamped conditions for which oscillations arise, and overdamped conditions for which there are no oscillations. Through numerical inversion of the Laplace transform solution, type curves from the mathematical model are developed to estimate formation properties through comparison with the measured hydraulic response in the pumped well. The

[An unexpected stage of alkalosis in the dynamics of the early posthemorrhagic period].

PubMed

Beliaev, A V

2000-01-01

A study was made on acid-base metabolism in early posthemorrhagic period as exemplified by examination of patients presenting with gastrointestinal hemorrhage. It has been ascertained that hemorrhage is accompanied by a mixed variant of the acid-base state (ABS) deviation, namely metabolic lactate-acidosis and respiratory alkalosis. In the time-related course of posthemorrhagic period such deviations persist in patients with lethal outcome; with the disease running a favourable course the above deviations are found to return to normal quite soon. The development of complications leads to staging in ABC, its stages being as follows: stage I--the initial stage, stage II--persisting metabolic acidosis and respiratory alkalosis, stage III--alkalosis, stage IV--normalization, with stage III of ABS being encouraged by hypocapnia caused by function disorders of the lungs in early posthemorrhagic period, normalization of cell metabolism, increase in the rate of urination as a reflection of the third earlier identified stage of water metabolism, with the H+ excretion in the urine at the previous level. The identified ABS stage III threatens coming trouble, being accompanied by metabolic deviations together with a risk of function disorder of the myocardium.

Parents' Views on the Use of Technology in the Early Childhood Period

ERIC Educational Resources Information Center

Ekici, Fatma Yasar

2016-01-01

The main aim of this research is to examine parents' views on technology use in the early childhood period. Survey method was used in this research. The research population consists of the parents, whose children go to the pre-school education institutions in Istanbul province. The research sample consists of 477 parents chosen by the random…

ROTATION PERIODS OF WIDE BINARIES IN THE KEPLER FIELD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Janes, K. A.

In a search of proper motion catalogs for common proper motion stars in the field of the Kepler spacecraft I identified 93 likely binary systems. A comparison of their rotation periods is a test of the gyrochronology concept. To find their periods I calculated the autocorrelation function (ACF) of the Kepler mission photometry for each star. In most systems for which good periods can be found, the cooler star has a longer period than the hotter component, in general agreement with models. However, there is a wide range in the gradients of lines connecting binary pairs in a period–color diagram.more » Furthermore, near the solar color, only a few stars have longer periods than the Sun, suggesting that they, and their cooler companions, are not much older than the Sun. In addition, there is an apparent gap at intermediate periods in the period distribution of the late K and early M stars. Either star formation in this direction has been variable, or stars evolve in period at a non-uniform rate, or some stars evolve more rapidly than others at the same mass. Finally, using the ACF as a measure of the activity level, I found that while the F, G, and early K stars become less active as their periods increase, there is no correlation between period and activity for the mid K to early M stars.« less

Concept Formation Skills in Long-Term Cochlear Implant Users

PubMed Central

Castellanos, Irina; Kronenberger, William G.; Beer, Jessica; Colson, Bethany G.; Henning, Shirley C.; Ditmars, Allison; Pisoni, David B.

2015-01-01

This study investigated if a period of auditory sensory deprivation followed by degraded auditory input and related language delays affects visual concept formation skills in long-term prelingually deaf cochlear implant (CI) users. We also examined if concept formation skills are mediated or moderated by other neurocognitive domains (i.e., language, working memory, and executive control). Relative to normally hearing (NH) peers, CI users displayed significantly poorer performance in several specific areas of concept formation, especially when multiple comparisons and relational concepts were components of the task. Differences in concept formation between CI users and NH peers were fully explained by differences in language and inhibition–concentration skills. Language skills were also found to be more strongly related to concept formation in CI users than in NH peers. The present findings suggest that complex relational concepts may be adversely affected by a period of early prelingual deafness followed by access to underspecified and degraded sound patterns and spoken language transmitted by a CI. Investigating a unique clinical population such as early-implanted prelingually deaf children with CIs can provide new insights into foundational brain–behavior relations and developmental processes. PMID:25583706

Late Noachian Climate Of Mars: Constraints From Valley Network System Formation Times And The Intermittencies (Episodic/Periodic And Punctuated).

NASA Astrophysics Data System (ADS)

Head, James

2017-04-01

Formation of Late Noachian-Early Hesperian (LN-EH) valley network systems (VNS) signaled the presence of warm/wet conditions generating several hypotheses for climates permissive of these conditions. To constrain options for the ambient Noachian climate, we examine estimates for time required to carve channels/deltas and total duration implied by plausible intermittencies. Formation Times for VN, OBL, Deltas, Fans: A synthesis of required timescales show that even with the longest estimated continuous duration of VN formation/intermittencies, total time to carve the VN does not exceed 106 years, <˜0.25% of the total Noachian. Intermittency/episodicity assumptions are climate-model dependent (e.g., most workers use Earth-like fluvial activity and intermittency). Noachian-Early Hesperian Climate Models: 1) Warm and wet/semiarid/arid climate: Sustained background MAT >273 K, hydrological system vertically integrated, and rainfall occurs to recharge the aquifer. Two subtypes: a) "Rainfall/Fluvial Erosion-Dominated Warm and Wet Model": "Rainfall and surface runoff" persist throughout Noachian to explain crater degradation, and a LN-EH short rapidly ending terminal epoch. b) "Recharge Evaporation/Evaporite Dominated Warm and Wet Model": Sustained period of equatorial/mid-latitude precipitation and a vertically integrated hydrological system driven by evaporative upwelling and fluctuating shallow water table playa environments account for sulfate evaporate environments at Meridiani Planum. Sustained temperatures >273 K are required for extended periods (107-108 years). 2) Cold and icy climate: Sustained background temperatures extremely low (MAT ˜225 K), cryosphere is globally continuous, hydrological system is horizontally stratified, separating groundwater system from surface; no combination of spin-axis/orbital perturbations can raise MAT to 273 K. Adiabatic cooling effects transfer water to high altitudes, leading to "Late Noachian Icy Highlands Model". VNS cannot

Controls on Cyclic Formation of Quaternary Early Diagenetic Dolomite

NASA Astrophysics Data System (ADS)

McCormack, J.; Bontognali, T. R. R.; Immenhauser, A.; Kwiecien, O.

2018-04-01

The origin of sedimentary dolomite and the factors that control its formation within the geological record remain speculative. In most models, dolomite formation is linked to evaporative conditions, high water temperature, increasing Mg/Ca ratio, increasing alkalinity, and high amounts of biomass. Here we challenge these archetypal views, by documenting a case example of Quaternary dolomite which formed in Lake Van at constantly low temperature (<4°C) and without direct control of the latter conditions. Dolomite occurs within highstand sediments related to suborbital climate variability (Dansgaard-Oeschger cycles). We propose that dolomite precipitation is a product of a microbially influenced process, triggered by ecological stress, resulting from reventilation of the water-sediment interface. Independently from the validity of this hypothesis, our results call for a reevaluation of the paleoenvironmental conditions often invoked for early diagenetic dolomite-rich intervals within sedimentary sequences and for caution when interpreting time series of subrecent lacustrine carbonates.

Embryo sac formation and early embryo development in Agave tequilana (Asparagaceae).

PubMed

González-Gutiérrez, Alejandra G; Gutiérrez-Mora, Antonia; Rodríguez-Garay, Benjamín

2014-01-01

Agave tequilana is an angiosperm species that belongs to the family Asparagaceae (formerly Agavaceae). Even though there is information regarding to some aspects related to the megagametogenesis of A. tequilana, this is the first report describing the complete process of megasporogenesis, megagametogenesis, the early embryo and endosperm development process in detail. The objective of this work was to study and characterize all the above processes and the distinctive morphological changes of the micropylar and chalazal extremes after fertilization in this species. The agave plant material for the present study was collected from commercial plantations in the state of Jalisco, Mexico. Ovules and immature seeds, previously fixed in FAA and kept in ethanol 70%, were stained based on a tissue clarification technique by using a Mayer's-Hematoxylin solution. The tissue clarification technique was successfully used for the characterization of the megasporogenesis, megagametogenesis, mature embryo sac formation, the early embryo and endosperm development processes by studying intact cells. The embryo sac of A. tequilana was confirmed to be of the monosporic Polygonum-type and an helobial endosperm formation. Also, the time-lapse of the developmental processes studied was recorded.

Hrs regulates early endosome fusion by inhibiting formation of an endosomal SNARE complex

PubMed Central

Sun, Wei; Yan, Qing; Vida, Thomas A.; Bean, Andrew J.

2003-01-01

Movement through the endocytic pathway occurs principally via a series of membrane fusion and fission reactions that allow sorting of molecules to be recycled from those to be degraded. Endosome fusion is dependent on SNARE proteins, although the nature of the proteins involved and their regulation has not been fully elucidated. We found that the endosome-associated hepatocyte responsive serum phosphoprotein (Hrs) inhibited the homotypic fusion of early endosomes. A region of Hrs predicted to form a coiled coil required for binding the Q-SNARE, SNAP-25, mimicked the inhibition of endosome fusion produced by full-length Hrs, and was sufficient for endosome binding. SNAP-25, syntaxin 13, and VAMP2 were bound from rat brain membranes to the Hrs coiled-coil domain. Syntaxin 13 inhibited early endosomal fusion and botulinum toxin/E inhibition of early endosomal fusion was reversed by addition of SNAP-25(150–206), confirming a role for syntaxin 13, and establishing a role for SNAP-25 in endosomal fusion. Hrs inhibited formation of the syntaxin 13–SNAP-25–VAMP2 complex by displacing VAMP2 from the complex. These data suggest that SNAP-25 is a receptor for Hrs on early endosomal membranes and that the binding of Hrs to SNAP-25 on endosomal membranes inhibits formation of a SNARE complex required for homotypic endosome fusion. PMID:12847087

Simulations of Early Structure Formation: Primordial Gas Clouds

NASA Astrophysics Data System (ADS)

Yoshida, Naoki; Abel, Tom; Hernquist, Lars; Sugiyama, Naoshi

2003-08-01

molecules are rapidly dissociated, rendering gas cooling inefficient. In both the cases we consider, the overall effect can be described by computing an equilibrium H2 abundance for the radiation flux and defining an effective shielding factor. Based on our numerical results, we develop a semianalytic model of the formation of the first stars and demonstrate how it can be coupled with large N-body simulations to predict the star formation rate in the early universe.

Early and late hot extremes, and elongation of the warm period over Greece

NASA Astrophysics Data System (ADS)

Founda, Dimitra; Giannakopoulos, Christos; Pierros, Fragiskos

2017-04-01

The eastern Mediterranean has been assigned as one of the most responsive areas in climate change, mainly with respect to the occurrence of warmer and drier conditions. In Greece in particular, observations suggest prominent increases in the summer air temperature which in some areas amount to approximately 1 0C/decade since the mid 1970s, while Regional Climate Models simulate further increases in the near and distant future. These changes are coupled with simultaneous increase in the occurrence of hot extremes. In addition to changes in the frequency and intensity of hot extrems, timing of occurrence is also of special interest. Early heat waves in particular, have been found to increase thermal risk in humans. The study explores variations and trends in timing, namely the date of first and last occurrence of hot extremes within the year, and subsequently the hot extremes period (season), defined as the time interval (number of days) between first and last hot extremes occurrence, over Greece. A case study for the area of Athens covering a longer than 100-years period (1897-2015) was conducted first, which will be extended to other Greek areas. Several heat related climatic indices were used, based either on predefined temperature thresholds such as 'tropical days' (daily maximum air temperature, Tmax >30 0C), 'tropical nights' (daily minimum air temperature, Tmin >20 0C), 'hot days' (Tmax >35 0C), or on local climate statistics such as days with Tmax (or Tmin) > 95th percentile. The analysis revealed significant changes in the period of hot extremes and specifically elongation of the period, attributed to early rather than late hot extremes occurrence. An earlier shift of the first tropical day and the first tropical night occurrence by approximately 2 days/decade was found over the study period. An overall elongation of the 'hot days' season by 2.6 days/decade was also observed, which is more prominent since the early 1980s. Over the last three decades, earlier

Schedules for home visits in the early postpartum period.

PubMed

Yonemoto, Naohiro; Dowswell, Therese; Nagai, Shuko; Mori, Rintaro

2017-08-02

Maternal complications including psychological and mental health problems and neonatal morbidity have been commonly observed in the postpartum period. Home visits by health professionals or lay supporters in the weeks following the birth may prevent health problems from becoming chronic with long-term effects on women, their babies, and their families. To assess outcomes for women and babies of different home-visiting schedules during the early postpartum period. The review focuses on the frequency of home visits, the duration (when visits ended) and intensity, and on different types of home-visiting interventions. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (28 January 2013) and reference lists of retrieved articles. Randomised controlled trials (RCTs) (including cluster-RCTs) comparing different types of home-visiting interventions enrolling participants in the early postpartum period (up to 42 days after birth). We excluded studies in which women were enrolled and received an intervention during the antenatal period (even if the intervention continued into the postnatal period) and studies recruiting only women from specific high-risk groups. (e.g. women with alcohol or drug problems). Study eligibility was assessed by at least two review authors. Data extraction and assessment of risk of bias were carried out independently by at least two review authors. Data were entered into Review Manager software. We included data from 12 randomised trials with data for more than 11,000 women. The trials were carried out in countries across the world, and in both high- and low-resource settings. In low-resource settings women receiving usual care may have received no additional postnatal care after early hospital discharge.The interventions and control conditions varied considerably across studies with trials focusing on three broad types of comparisons: schedules involving more versus fewer postnatal home visits (five studies), schedules

Acclimation of peanut (Arachis hypogaea L.) to water stress through exposure to differing periods of early season drought

USDA-ARS?s Scientific Manuscript database

Peanut (Arachis hypogaea L.) is able to withstand periods of water scarcity either in the early or late periods of the growing season, but suffers significant stress and yield loss during drought periods in mid-season, or the period coinciding with peak flower production and pod maturation. In fact...

Early memory formation disrupted by atypical PKC inhibitor ZIP in the medial prefrontal cortex but not hippocampus

PubMed Central

Evuarherhe, Obaro; Barker, Gareth R. I.; Savalli, Giorgia; Warburton, Elizabeth C.; Brown, Malcolm W.

2014-01-01

Atypical isoforms of protein kinase C (aPKCs; particularly protein kinase M zeta: PKMζ) have been hypothesised to be necessary and sufficient for the maintenance of long-term potentiation (LTP) and long term memory by maintaining postsynaptic AMPA receptors via the GluR2 subunit. A myristoylated PKMζ pseudosubstrate peptide (ZIP) blocks PKMζ activity. We examined the actions of ZIP in medial prefrontal cortex (mPFC) and hippocampus in associative recognition memory in rats during early memory formation and memory maintenance. ZIP infusion in either hippocampus or mPFC impaired memory maintenance. However, early memory formation was impaired by ZIP in mPFC but not hippocampus; and blocking GluR2-dependent removal of AMPA receptors did not affect this impairment caused by ZIP in the mPFC. The findings indicate: (i) a difference in the actions of ZIP in hippocampus and medial prefrontal cortex, and (ii) a GluR2-independent target of ZIP (possibly PKCλ) in the mPFC during early memory formation. PMID:24729442

Parents' Marital Distress, Divorce, and Remarriage: Links with Daughters' Early Family Formation Transitions

ERIC Educational Resources Information Center

Amato, Paul R.; Kane, Jennifer B.

2011-01-01

The authors used data from the Add Health study to estimate the effects of parents' marital status and relationship distress on daughters' early family formation transitions. Outcomes included traditional transitions (marriage and marital births) and nontraditional transitions (cohabitation and nonmarital births). Relationship distress among…

Formation of laser-induced periodic surface structures on fused silica upon two-color double-pulse irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Höhm, S.; Herzlieb, M.; Rosenfeld, A.

2013-12-16

The formation of laser-induced periodic surface structures (LIPSS) upon irradiation of fused silica with multiple irradiation sequences consisting of laser pulse pairs (50 fs single-pulse duration) of two different wavelengths (400 and 800 nm) is studied experimentally. Parallel polarized double-pulse sequences with a variable delay Δt between −10 and +10 ps and between the individual fs-laser pulses were used to investigate the LIPSS periods versus Δt. These two-color experiments reveal the importance of the ultrafast energy deposition to the silica surface by the first laser pulse for LIPSS formation. The second laser pulse subsequently reinforces the previously seeded spatial LIPSSmore » frequencies.« less

Thrombolysis with intravenous recombinant tissue plasminogen activator during early postpartum period: a review of the literature.

PubMed

Akazawa, Munetoshi; Nishida, Makoto

2017-05-01

Thromboembolic events are one of the leading causes of maternal death during the postpartum period. Postpartum thrombolytic therapy with recombinant tissue plasminogen activator (rt-PA) is controversial because the treatment may lead to massive bleeding. Data centralization may be beneficial for analyzing the safety and effectiveness of systemic thrombolysis during the early postpartum period. We performed a computerized MEDLINE and EMBASE search. We collected data for 13 cases of systemic thrombolytic therapy during the early postpartum period, when limiting the early postpartum period to 48 hours after delivery. Blood transfusion was necessary in all cases except for one (12/13; 92%). In seven cases (7/13; 54%), a large amount of blood was required for transfusion. Subsequent laparotomy to control bleeding was required in five cases (5/13; 38%), including three cases of hysterectomy and two cases of hematoma removal, all of which involved cesarean delivery. In cases of transvaginal delivery, there was no report of laparotomy. The occurrence of severe bleeding was high in relation to cesarean section, compared with vaginal deliveries. Using rt-PA in relation to cesarean section might be worth avoiding. However, the paucity of data in the literature makes it difficult to assess the ultimate outcomes and safety of this treatment. © 2017 Nordic Federation of Societies of Obstetrics and Gynecology.

Early Visean bryozoans from the Shishtu II Member, Shishtu Formation, central Iran

NASA Astrophysics Data System (ADS)

Tolokonnikova, Zoya; Yazdi-Moghadam, Mohsen

2013-12-01

Four bryozoan species are described from the upper member (Shishtu II) (Visean, Early Carboniferous=Mississippian) of the Shishtu Formation of central Iran: Nikiforovella ulbensis Nekhoroshev, 1956, Nicklesopora elegantulaformis (Nekhoroshev, 1956), Primorella cf. iranica Gorjunova, 2006, and Nikiforopora intermedia (Nikiforova, 1950). This Visean assemblage shows close palaeogeographical affinities of Iran with Kazakhstan and Russia (eastern Transbaikalia, Kurgan region).

Temporal trends of latency period and perinatal survival after very early preterm premature rupture of fetal membranes.

PubMed

González-Mesa, Ernesto; Herrera, José A; Urgal, Amaya; Lazarraga, Cristina; Benítez, María J; Gómez, Cristina

2012-08-01

This paper shows temporal trends of latency period and perinatal survival after preterm premature rupture of membranes at or before 28 weeks (very early PPROM). We have studied retrospectively medical records of all cases of very early PPROM attended in our Obstetric Department from January 1, 2000 to December 31, 2010. A total of 327 cases of very early PPROM were attended, representing 0.4 % of all deliveries, 3.68 % of all preterm births and 15 % of cases all of PPROM. The mean gestational age at delivery was 27 weeks (range 20-34). The mean duration of latency period for the total of 327 cases was 12.1 days (range 0-83, SD 13.3), with a clear trend to its increase from 2005 (p < 0.05). The mean duration of latency period was largest in 2010 (p < 0.05). For the whole period 2000-2010, perinatal deaths reached 30.6 % of all cases, with a clear trend to decrease as gestational age at diagnosis increased, and over the years of study. We have also found a high rate of obstetric complications and a high rate of cesarean deliveries. The upward trend in the duration of latency period in all groups over the years of study and the encouraging perinatal survival observed, even in previable PPROM, are incentives to follow expectant/conservative management in these cases.

Physical conditions on the early Earth.

PubMed

Lunine, Jonathan I

2006-10-29

The formation of the Earth as a planet was a large stochastic process in which the rapid assembly of asteroidal-to-Mars-sized bodies was followed by a more extended period of growth through collisions of these objects, facilitated by the gravitational perturbations associated with Jupiter. The Earth's inventory of water and organic molecules may have come from diverse sources, not more than 10% roughly from comets, the rest from asteroidal precursors to chondritic bodies and possibly objects near Earth's orbit for which no representative class of meteorites exists today in laboratory collections. The final assembly of the Earth included a catastrophic impact with a Mars-sized body, ejecting mantle and crustal material to form the Moon, and also devolatilizing part of the Earth. A magma ocean and steam atmosphere (possibly with silica vapour) existed briefly in this period, but terrestrial surface waters were below the critical point within 100 million years after Earth's formation, and liquid water existed continuously on the surface within a few hundred million years. Organic material delivered by comets and asteroids would have survived, in part, this violent early period, but frequent impacts of remaining debris probably prevented the continuous habitability of the Earth for one to several hundred million years. Planetary analogues to or records of this early time when life began include Io (heat flow), Titan (organic chemistry) and Venus (remnant early granites).

The formation mechanism and evolution of ps-laser-induced high-spatial-frequency periodic surface structures on titanium

NASA Astrophysics Data System (ADS)

Pan, A. F.; Wang, W. J.; Mei, X. S.; Yang, H. Z.; Sun, X. F.

2017-01-01

We report the formation and evolution mechanisms of HSFLs (high-spatial-frequency laser-induced periodic surface structures) on the commercial pure titanium under 10-ps 532-nm-wavelength laser irradiation. At a lower peak laser fluence, HSFLs in the rough zone are first formed along the surface texture. Subsequently, HSFLs in the flat zone are formed with an orientation parallel to the laser polarization direction. The formation of HSFLs can be attributed to the parallel orientation of the initial periodic modulation of the electron plasma concentration to the laser polarization direction. In particular, the formation of HSFLs along the surface texture occurs because the absorbed laser energy density is along the surface texture. At a higher peak laser fluence, two types of HSFLs appear together with LSFLs. The first type involves HSFLs that initially cover the concave part of the LSFL (low-spatial-frequency laser-induced periodic surface structures) and penetrate inward as the number of spot overlaps increases. This formation mechanism can be attributed to cavitation instability. The second type involves HSFLs that are initially in the convex part of the LSFL, and they are transformed into oxidized nanodots as the number of spot overlaps increases. The oxidized nanodots increase the absorption of laser energy in titanium, which leads to the ablation and removal of the oxidized material. Therefore, the surface of the LSFL becomes smooth.

Early Acheulean technology in the Rietputs Formation, South Africa, dated with cosmogenic nuclides.

PubMed

Gibbon, Ryan J; Granger, Darryl E; Kuman, Kathleen; Partridge, Timothy C

2009-02-01

An absolute dating technique based on the build-up and decay of (26)Al and (10)Be in the mineral quartz provides crucial evidence regarding early Acheulean hominid distribution in South Africa. Cosmogenic nuclide burial dating of an ancient alluvial deposit of the Vaal River (Rietputs Formation) in the western interior of South Africa shows that coarse gravel and sand aggradation there occurred ca 1.57+/-0.22Ma, with individual ages of samples ranging from 1.89+/-0.19 to 1.34+/-0.22Ma. This was followed by aggradation of laminated and cross-bedded fine alluvium at ca 1.26+/-0.10Ma. The Rietputs Formation provides an ideal situation for the use of the cosmogenic nuclide burial dating method, as samples could be obtained from deep mining pits at depths ranging from 7 to 16 meters. Individual dates provide only a minimum age for the stone tool technology preserved within the deposits. Each assemblage represents a time averaged collection. Bifacial tools distributed throughout the coarse gravel and sand unit can be assigned to an early phase of the Acheulean. This is the first absolute radiometric dated evidence for early Acheulean artefacts in South Africa that have been found outside of the early hominid sites of the Gauteng Province. These absolute dates also indicate that handaxe-using hominids inhabited southern Africa as early as their counterparts in East Africa. The simultaneous appearance of the Acheulean in different parts of the continent implies relatively rapid technology development and the widespread use of large cutting tools in the African continent by ca 1.6Ma.

Serum and saliva cortisol relations in adolescents during pregnancy and the early postpartum period.

PubMed

Dorn, L D; Susman, E J

1993-08-15

The purpose of this investigation was to examine: (1) relations between serum and saliva cortisol in adolescents in pregnancy and early postpartum and (2) short-term consistency of serum and saliva cortisol across three samples, 20 minutes apart, as well as the long-term consistency from pregnancy to early postpartum. Pregnant adolescents (n = 40), ages 14 to 19 years, were enrolled in this study. Subjects were seen at 20 weeks gestation or earlier (T1), 34-36 weeks gestation (T2), and 2-3 weeks postpartum (T3). Blood samples were drawn at T1 and T3, at 0, 20, and 40 minutes. Saliva samples were collected across the same 40-minute period at T1, T2, and T3. Spearman rho (rs) correlation coefficients between serum and saliva ranged from 0.72 to 0.77 (T1), and 0.42 to 0.60 (T3) (p < or = 0.05). Short-term consistency between serum cortisol samples was 0.86-0.97 at T1 and 0.60-0.82 at T3. Short-term consistency for saliva cortisol samples was 0.70-0.96 at T1, 0.91-0.95 at T2, and 0.64-0.89 at T3. Long-term consistency (T1 to T3) for serum and saliva cortisol was low. Individual differences as well as dramatic changes in the endocrine environment in pregnancy and the early postpartum period may explain the more moderate serum-saliva correlations in the postpartum period.

COMPARISON OF GESTATIONAL AGE AT DELIVERY BASED ON LAST MENSTRUAL PERIOD AND EARLY ULTRASOUND

EPA Science Inventory

Reported date of last menstrual period (LMP) is commonly used to estimate gestational age but may be unreliable if recall is inaccurate or time between menstruation and ovulation differs from the presumed 15-day interval. Early ultrasound is generally a more accurate method than ...

A redescription of Lithornis vulturinus (Aves, Palaeognathae) from the Early Eocene Fur Formation of Denmark.

PubMed

Bourdon, Estelle; Lindow, Bent

2015-10-20

The extinct Lithornithidae include several genera and species of flying palaeognathous birds of controversial affinities known from the Early Paleogene of North America and Europe. An almost complete, articulated skeleton from the Early Eocene marine deposits of the Fur Formation (Denmark) was recently assigned to Lithornis vulturinus Owen, 1840. This study provides a detailed redescription and comparison of this three-dimensionally preserved specimen (MGUH 26770), which is one of the best preserved representatives of the Lithornithidae yet known. We suggest that some new features might be diagnostic of Lithornis vulturinus, including a pterygoid fossa shallower than in other species of Lithornis and the presence of a small caudal process on the os palatinum. We propose that Lithornis nasi (Harrison, 1984) is a junior synonym of Lithornis vulturinus and we interpret minor differences in size and shape among the specimens as intraspecific variation. To date, Lithornis vulturinus is known with certainty from the latest Paleocene-earliest Eocene to Early Eocene of the North Sea Basin (Ølst, Fur and London Clay Formations). Among the four species of the genus Lithornis, the possibility that Lithornis plebius Houde, 1988 (Early Eocene of Wyoming) is conspecific with either Lithornis vulturinus or Lithornis promiscuus Houde, 1988 (Early Eocene of Wyoming) is discussed. The presence of closely related species of Lithornis on either side of the North Atlantic in the Early Eocene reflects the existence of a high-latitude land connection between Europe and North America at that time.

Effect of Formative and Ability Test Results on Early Learning of Students

ERIC Educational Resources Information Center

Kadir, Abdul; Ardi, Muhammad; Nurhayati, B.; Dirawan, Gufran Darma

2016-01-01

The objective of this study was to examine the relationship of formative tests to early learning ability of students in the science learning style. This research used an experimental method with a 2 x 2 factorial design. The participants comprised all the students in class VII of the Islamic Junior High School State of Kolaka, a total of 343…

Sedimentology of the Early Jurassic terrestrial Steierdorf Formation in Anina, Colonia Cehă Quarry, South Carpathians, Romania

NASA Astrophysics Data System (ADS)

Kędzior, Artur; Popa, Mihai E.

2013-06-01

Kędzior, A. and Popa, E.M. 2013. Sedimentology of the Early Jurassic terrestrial Steierdorf Formation in Anina, Colonia Cehă Quarry, South Carpathians, Romania. Acta Geologica Polonica, 63 (2), 175-199. Warszawa. The continental, coal bearing Steierdorf Formation, Hettangian - Sinemurian in age, is included in the Mesozoic cover of the Reşiţa Basin, Getic Nappe, South Carpathians, Romania. The Steierdorf Formation can be studied in Anina, a coal mining center and an exceptional locality for Early Jurassic flora and fauna, occurring in the middle of the Reşiţa Basin. This paper presents the results of sedimentological, stratigraphical and paleobotanical researches undertaken in Colonia Cehă open cast mine in Anina, where the Steierdorf Formation outcrops widely. Several sedimentary facies associations have been described, these associations permitting the reconstruction of various depositional systems such as alluvial fans, braided and meandering river systems, as well as lacustrine and coal generating marsh systems of the Steierdorf Formation. The sedimentary associations recorded within the Steierdorf Formation show a gradual fining upward trend, pointing to a rising marine water table and a decreasing relief within the source area.

Dissociation between Complete Hippocampal Context Memory Formation and Context Fear Acquisition

ERIC Educational Resources Information Center

Leake, Jessica; Zinn, Raphael; Corbit, Laura; Vissel, Bryce

2017-01-01

Rodents require a minimal time period to explore a context prior to footshock to display plateau-level context fear at test. To investigate whether this rapid fear plateau reflects complete memory formation within that short time-frame, we used the immediate-early gene product Arc as an indicator of hippocampal context memory formation-related…

Formation of periodic interfacial misfit dislocation array at the InSb/GaAs interface via surface anion exchange

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jia, Bo Wen; Tan, Kian Hua; Loke, Wan Khai

The relationship between growth temperature and the formation of periodic interfacial misfit (IMF) dislocations via the anion exchange process in InSb/GaAs heteroepitaxy was systematically investigated. The microstructural and electrical properties of the epitaxial layer were characterized using atomic force microscope, high-resolution x-ray diffraction, transmission electron microscopy, and Hall resistance measurement. The formation of interfacial misfit (IMF) dislocation arrays depended on growth temperature. A uniformly distributed IMF array was found in a sample grown at 310 °C, which also exhibited the lowest threading dislocation density. The analysis suggested that an incomplete As-for-Sb anion exchange process impeded the formation of IMF on samplemore » grown above 310 °C. At growth temperature below 310 °C, island coalescence led to the formation of 60° dislocations and the disruption of periodic IMF array. All samples showed higher electron mobility at 300 K than at 77 K.« less

Old Dogs Learning New Tricks: Neuroplasticity beyond the Juvenile Period

ERIC Educational Resources Information Center

Lillard, Angeline S.; Erisir, Alev

2011-01-01

Twenty years ago, the prevalent view in Psychology was that although learning and the formation of new memories are lifelong occurrences, the neural changes associated with these events were all in the existing receptors. No new neural hardware, from synapses to neurons, was thought to appear after a protracted period early in life. In the past 20…

Reversal of Fortune: Increased Star Formation Efficiencies in the Early Histories of Dwarf Galaxies?

NASA Astrophysics Data System (ADS)

Madau, Piero; Weisz, Daniel R.; Conroy, Charlie

2014-08-01

On dwarf galaxy scales, the different shapes of the galaxy stellar mass function and the dark halo mass function require a star-formation efficiency (SFE) in these systems that is currently more than 1 dex lower than that of Milky Way-size halos. Here, we argue that this trend may actually be reversed at high redshift. Specifically, by combining the resolved star-formation histories of nearby isolated dwarfs with the simulated mass-growth rates of dark matter halos, we show that the assembly of these systems occurs in two phases: (1) an early, fast halo accretion phase with a rapidly deepening potential well, characterized by a high SFE; and (2) a late, slow halo accretion phase where, perhaps as a consequence of reionization, the SFE is low. Nearby dwarfs have more old stars than predicted by assuming a constant or decreasing SFE with redshift, a behavior that appears to deviate qualitatively from the trends seen among more massive systems. Taken at face value, the data suggest that at sufficiently early epochs, dwarf galaxy halos above the atomic cooling mass limit can be among the most efficient sites of star formation in the universe.

Incidence of double ovulation during the early postpartum period in lactating dairy cows.

PubMed

Kusaka, Hiromi; Miura, Hiroshi; Kikuchi, Motohiro; Sakaguchi, Minoru

2017-03-15

In lactating cattle, the incidence of twin calving has many negative impacts on production and reproduction in dairy farming. In almost all cases, natural twinning in dairy cattle is the result of double ovulation. It has been suggested that the milk production level of cows influences the number of ovulatory follicles. The objective of the present study was to investigate the incidence of double ovulations during the early postpartum period in relation to the productive and reproductive performance of dairy cows. The ovaries of 43 Holstein cows (26 primiparous and 17 multiparous) were ultrasonographically scanned throughout the three postpartum ovulation sequences. The incidence of double ovulation in the unilateral ovaries was 66.7%, with a higher incidence in the right ovary than in the left, whereas that in bilateral ovaries was 33.3%. When double ovulations were counted dividing into each side ovary in which ovulations occurred, the total frequency of ovulations deviated from a 1:1 ratio (60.3% in the right side and 39.7% in the left side, P < 0.05). In multiparous cows, double ovulation occurred more frequently than in primiparous cows (58.8% vs. 11.5% per cow and 30.0% vs. 3.8% per ovulation, respectively P < 0.01). The double ovulators experienced more anovulatory repeated waves of follicles before their first ovulations than the single ovulators, which resulted in an extension of the period from parturition to third ovulation (81.5 days vs. 64.2 days, P < 0.05). In the multiparous cows, the double ovulators exhibited higher peak milk yield (P < 0.01) with lower milk lactose concentration (P < 0.05), indicating the prevalence of a more severe negative energy balance during the postpartum 3-month compared to the multiparous single ovulators. Our results showed that, regardless of their parity, double ovulation had no impact on the reproductive performance of the cows. Two multiparous cows that experienced double ovulation during the early

The star formation history of early-type galaxies as a function of mass and environment

NASA Astrophysics Data System (ADS)

Clemens, M. S.; Bressan, A.; Nikolic, B.; Alexander, P.; Annibali, F.; Rampazzo, R.

2006-08-01

Using the third data release of the Sloan Digital Sky Survey (SDSS), we have rigorously defined a volume-limited sample of early-type galaxies in the redshift range 0.005 < z <= 0.1. We have defined the density of the local environment for each galaxy using a method which takes account of the redshift bias introduced by survey boundaries if traditional methods are used. At luminosities greater than our absolute r-band magnitude cut-off of -20.45, the mean density of environment shows no trend with redshift. We calculate the Lick indices for the entire sample and correct for aperture effects and velocity dispersion in a model-independent way. Although we find no dependence of redshift or luminosity on environment, we do find that the mean velocity dispersion, σ, of early-type galaxies in dense environments tends to be higher than in low-density environments. Taking account of this effect, we find that several indices show small but very significant trends with environment that are not the result of the correlation between indices and velocity dispersion. The statistical significance of the data is sufficiently high to reveal that models accounting only for α-enhancement struggle to produce a consistent picture of age and metallicity of the sample galaxies, whereas a model that also includes carbon enhancement fares much better. We find that early-type galaxies in the field are younger than those in environments typical of clusters but that neither metallicity, α-enhancement nor carbon enhancement are influenced by the environment. The youngest early-type galaxies in both field and cluster environments are those with the lowest σ. However, there is some evidence that the objects with the largest σ are slightly younger, especially in denser environments. Independent of environment both the metallicity and α-enhancement grow monotonically with σ. This suggests that the typical length of the star formation episodes which formed the stars of early-type galaxies

Influence of crystal orientation on the formation of femtosecond laser-induced periodic surface structures and lattice defects accumulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sedao, Xxx; Garrelie, Florence, E-mail: florence.garrelie@univ-st-etienne.fr; Colombier, Jean-Philippe

2014-04-28

The influence of crystal orientation on the formation of femtosecond laser-induced periodic surface structures (LIPSS) has been investigated on a polycrystalline nickel sample. Electron Backscatter Diffraction characterization has been exploited to provide structural information within the laser spot on irradiated samples to determine the dependence of LIPSS formation and lattice defects (stacking faults, twins, dislocations) upon the crystal orientation. Significant differences are observed at low-to-medium number of laser pulses, outstandingly for (111)-oriented surface which favors lattice defects formation rather than LIPSS formation.

Structural analysis of star-forming blue early-type galaxies. Merger-driven star formation in elliptical galaxies

NASA Astrophysics Data System (ADS)

George, Koshy

2017-02-01

Context. Star-forming blue early-type galaxies at low redshift can give insight to the stellar mass growth of L⋆ elliptical galaxies in the local Universe. Aims: We wish to understand the reason for star formation in these otherwise passively evolving red and dead stellar systems. The fuel for star formation can be acquired through recent accretion events such as mergers or flyby. The signatures of such events should be evident from a structural analysis of the galaxy image. Methods: We carried out structural analysis on SDSS r-band imaging data of 55 star-forming blue elliptical galaxies, derived the structural parameters, analysed the residuals from best-fit to surface brightness distribution, and constructed the galaxy scaling relations. Results: We found that star-forming blue early-type galaxies are bulge-dominated systems with axial ratio >0.5 and surface brightness profiles fitted by Sérsic profiles with index (n) mostly >2. Twenty-three galaxies are found to have n< 2; these could be hosting a disc component. The residual images of the 32 galaxy surface brightness profile fits show structural features indicative of recent interactions. The star-forming blue elliptical galaxies follow the Kormendy relation and show the characteristics of normal elliptical galaxies as far as structural analysis is concerned. There is a general trend for high-luminosity galaxies to display interaction signatures and high star formation rates. Conclusions: The star-forming population of blue early-type galaxies at low redshifts could be normal ellipticals that might have undergone a recent gas-rich minor merger event. The star formation in these galaxies will shut down once the recently acquired fuel is consumed, following which the galaxy will evolve to a normal early-type galaxy.

Depositional Architecture of Late Cambrian-Early Ordovician Siliciclastic Barik Formation; Al Huqf Area, Oman

NASA Astrophysics Data System (ADS)

Abbasi, Iftikhar Ahmed

2017-04-01

Early Paleozoic siliciclastics sediments of the Haima Supergroup are subdivided into a number of formations and members based on lithological characteristics of various rock sequences. One of the distinct sandstone sequence, the Barik Formation (Late Cambrian-Early Ordovician) of the Andam Group is a major deep gas reservoir in central Oman. The sandstone bodies are prospective reservoir rocks while thick shale and clay interbeds act as effective seal. Part of the Barik Formation (lower and middle part) is exposed in isolated outcrops in Al Huqf area as interbedded multistoried sandstone, and green and red shale. The sandstone bodies are up to 2 meters thick and can be traced laterally for 300 m to over 1 km. Most of sandstone bodies show both lateral and vertical stacking. Two types of sandstone lithofacies are identified on the basis of field characteristics; a plane-bedded sandstone lithofacies capping thick red and green color shale beds, and a cross-bedded sandstone lithofacies overlying the plane-bedded sandstone defining coarsening upward sequences. The plane-bedded sandstone at places contains Cruziana ichnofacies and bivalve fragments indicating deposition by shoreface processes. Thick cross-bedded sandstone is interpreted to be deposited by the fluvial dominated deltaic processes. Load-casts, climbing ripples and flaser-bedding in siltstone and red shale indicate influence of tidal processes at times during the deposition of the formation. This paper summarizes results of a study carried out in Al Huqf area outcrops to analyze the characteristics of the sandstone-body geometry, internal architecture, provenance and diagenetic changes in the lower and middle part of the formation. The study shows build-up of a delta complex and its progradation over a broad, low-angle shelf where fluvial processes operate beside shoreface processes in a vegetation free setting. Keywords: Andam Group, Barik Formation, Ordovician sandstone, Al Huqf, Central Oman,

Tumor-associated macrophages drive spheroid formation during early transcoelomic metastasis of ovarian cancer

PubMed Central

Yin, Mingzhu; Li, Xia; Tan, Shu; Zhou, Huanjiao Jenny; Ji, Weidong; Bellone, Stefania; Xu, Xiaocao; Zhang, Haifeng; Santin, Alessandro D.; Lou, Ge

2016-01-01

Tumor-associated macrophages (TAMs) can influence ovarian cancer growth, migration, and metastasis, but the detailed mechanisms underlying ovarian cancer metastasis remain unclear. Here, we have shown a strong correlation between TAM-associated spheroids and the clinical pathology of ovarian cancer. Further, we have determined that TAMs promote spheroid formation and tumor growth at early stages of transcoelomic metastasis in an established mouse model for epithelial ovarian cancer. M2 macrophage–like TAMs were localized in the center of spheroids and secreted EGF, which upregulated αMβ2 integrin on TAMs and ICAM-1 on tumor cells to promote association between tumor cells and TAM. Moreover, EGF secreted by TAMs activated EGFR on tumor cells, which in turn upregulated VEGF/VEGFR signaling in surrounding tumor cells to support tumor cell proliferation and migration. Pharmacological blockade of EGFR or antibody neutralization of ICAM-1 in TAMs blunted spheroid formation and ovarian cancer progression in mouse models. These findings suggest that EGF secreted from TAMs plays a critical role in promoting early transcoelomic metastasis of ovarian cancer. As transcoelomic metastasis is also associated with many other cancers, such as pancreatic and colon cancers, our findings uncover a mechanism for TAM-mediated spheroid formation and provide a potential target for the treatment of ovarian cancer and other transcoelomic metastatic cancers. PMID:27721235

Physical conditions on the early Earth

PubMed Central

Lunine, Jonathan I

2006-01-01

The formation of the Earth as a planet was a large stochastic process in which the rapid assembly of asteroidal-to-Mars-sized bodies was followed by a more extended period of growth through collisions of these objects, facilitated by the gravitational perturbations associated with Jupiter. The Earth's inventory of water and organic molecules may have come from diverse sources, not more than 10% roughly from comets, the rest from asteroidal precursors to chondritic bodies and possibly objects near Earth's orbit for which no representative class of meteorites exists today in laboratory collections. The final assembly of the Earth included a catastrophic impact with a Mars-sized body, ejecting mantle and crustal material to form the Moon, and also devolatilizing part of the Earth. A magma ocean and steam atmosphere (possibly with silica vapour) existed briefly in this period, but terrestrial surface waters were below the critical point within 100 million years after Earth's formation, and liquid water existed continuously on the surface within a few hundred million years. Organic material delivered by comets and asteroids would have survived, in part, this violent early period, but frequent impacts of remaining debris probably prevented the continuous habitability of the Earth for one to several hundred million years. Planetary analogues to or records of this early time when life began include Io (heat flow), Titan (organic chemistry) and Venus (remnant early granites). PMID:17008213

Peroxy defects in Rocks and H2O2 formation on the early Earth

NASA Astrophysics Data System (ADS)

Gray, A.; Balk, M.; Mason, P.; Freund, F.; Rothschild, L.

2013-12-01

An oxygen-rich atmosphere appears to have been a prerequisite for complex life to evolve on Earth and possibly elsewhere in the Universe. The question is still shrouded in uncertainty how free oxygen became available on the early Earth. Here we study processes of peroxy defects in silicate minerals which, upon weathering, generate mobilized electronic charge carriers resulting in oxygen formation in an initially anoxic subsurface environment. Reactive Oxygen Species (ROS) are precursors to molecular oxygen during this process. Due to their toxicity they may have strongly influenced the evolution of life. ROS are generated during hydrolysis of peroxy defects, which consist of pairs of oxygen anions. A second pathway for formation occurs during (bio) transformations of iron sulphide minerals. ROS are produced and consumed by intracellular and extracellular reactions of Fe, Mn, C, N, and S species. We propose that despite an overall reducing or neutral oxidation state of the macroenvironment and the absence of free O2 in the atmosphere, microorganisms on the early Earth had to cope with ROS in their microenvironments. They were thus under evolutionary pressure to develop enzymatic and other defenses against the potentially dangerous, even lethal effects of ROS and oxygen. We have investigated how oxygen might be released through weathering and test microorganisms in contact with rock surfaces. Our results show how early Life might have adapted to oxygen. Early microorganisms must have "trained" to detoxify ROS prior to the evolution of aerobic metabolism and oxygenic photosynthesis. A possible way out of this dilemma comes from a study of igneous and high-grade metamorphic rocks, whose minerals contain a small but significant fraction of oxygen anions in the valence state 1- , forming peroxy links of the type O3Si-OO-SiO3 [1, 2]. As water hydrolyzes the peroxy links hydrogen peroxide, H2O2, forms. Continued experimental discovery of H2O2 formation at rock

Early Adolescence: Celestial Meetings - Synodic Periods.

ERIC Educational Resources Information Center

Science and Children, 1985

1985-01-01

Rather than memorize numbers for sidereal periods of planets (time to orbit the sun), students can learn to determine these times through simple calculations. Comparison of a planet's synodic period to earth's year of 365 days is made, then multiplication to derive a full circle of 360 degrees establishes the sidereal period. (DH)

Early-onset neonatal sepsis is associated with a high heart rate during automatically selected stationary periods.

PubMed

Nguyen, Nga; Vandenbroucke, Laurent; Hernández, Alfredo; Pham, Tu; Beuchée, Alain; Pladys, Patrick

2017-05-01

This study examined the heart rate variability characteristics associated with early-onset neonatal sepsis in a prospective, observational controlled study. Eligible patients were full-term neonates hospitalised with clinical signs that suggested early-onset sepsis and a C-reactive protein of >10 mg/L. Sepsis was considered proven in cases of symptomatic septicaemia, meningitis, pneumonia or enterocolitis. Heart rate variability parameters (n = 16) were assessed from five-, 15- and 30-minute stationary sequences automatically selected from electrocardiographic recordings performed at admission and compared with a control group using the U-test with post hoc Benjamini-Yekutieli correction. Stationary sequences corresponded to the periods with the lowest changes of heart rate variability over time. A total of 40 full-term infants were enrolled, including 14 with proven sepsis. The mean duration of the cardiac cycle length was lower in the proven sepsis group than in the control group (n = 11), without other significant changes in heart rate variability parameters. These durations, measured in five-minute stationary periods, were 406 (367-433) ms in proven sepsis group versus 507 (463-522) ms in the control group (p < 0.05). Early-onset neonatal sepsis was associated with a high mean heart rate measured during automatically selected stationary periods. ©2017 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

In situ monitoring of laser-induced periodic surface structures formation on polymer films by grazing incidence small-angle X-ray scattering.

PubMed

Rebollar, Esther; Rueda, Daniel R; Martín-Fabiani, Ignacio; Rodríguez-Rodríguez, Álvaro; García-Gutiérrez, Mari-Cruz; Portale, Giuseppe; Castillejo, Marta; Ezquerra, Tiberio A

2015-04-07

The formation of laser-induced periodic surface structures (LIPSS) on model spin-coated polymer films has been followed in situ by grazing incidence small-angle X-ray scattering (GISAXS) using synchrotron radiation. The samples were irradiated at different repetition rates ranging from 1 up to 10 Hz by using the fourth harmonic of a Nd:YAG laser (266 nm) with pulses of 8 ns. Simultaneously, GISAXS patterns were acquired during laser irradiation. The variation of both the GISAXS signal with the number of pulses and the LIPSS period with laser irradiation time is revealing key kinetic aspects of the nanostructure formation process. By considering LIPSS as one-dimensional paracrystalline lattice and using a correlation found between the paracrystalline disorder parameter, g, and the number of reflections observed in the GISAXS patterns, the variation of the structural order of LIPSS can be assessed. The role of the laser repetition rate in the nanostructure formation has been clarified. For high pulse repetition rates (i.e., 10 Hz), LIPSS evolve in time to reach the expected period matching the wavelength of the irradiating laser. For lower pulse repetition rates LIPSS formation is less effective, and the period of the ripples never reaches the wavelength value. Results support and provide information on the existence of a feedback mechanism for LIPSS formation in polymer films.

The formation of citizens: the pediatrician's role.

PubMed

Campos Júnior, Dioclécio

2016-01-01

This review article aims to define the fundamental role of the pediatrician in the formation of citizens in the 21st century. Significant bibliographical contributions produced by neuroscience, ecology, and epigenetics in the early childhood scenario. Many diseases that impair the lives of adults result from severe and often uncontrollable disorders that occur in early childhood, an irreplaceable period for the safe construction of the human brain, personality, and intelligence. There is noteworthy scientific evidence that has become unquestionable, according to which abuse and neglect and other forms of violence to which children are exposed during the course of their lives, are the genesis of many physical ailments and other mental diseases, including depressive morbidity and schizophrenia. Conversely, it is also emphasized that healthy practices such as reading and listening to/playing music are able to intensively contribute to the exercise of cognitive capacity inherent to this period of life, as a prerequisite for the acquisition of learning indispensable to the high educational performance during the schooling period. In the light of the disclosed scientific evidence, the pediatrician emerges as the most differentiated professional to provide preventive and curative care indispensable to the skilled formation of a healthy citizen. Copyright © 2016 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

The effect of early pregnancy on the formation of obstetric fistula.

PubMed

Browning, Andrew; Mbise, Frederick; Foden, Phil

2017-09-01

To assess the effect of early pregnancy on obstetric fistula. A prospective observational study was conducted among patients with obstetric fistula caused by a long obstructed labor who presented at Selian Lutheran Hospital, Tanzania, or Kitovu Hospital, Uganda, between January 1, 2015, and January 31, 2016. Demographic and clinical variables were evaluated. Among 270 patients, 162 (60.0%) experienced their first pregnancy up to 2 years after menarche (early group) and 108 (40.0%) experienced their first pregnancy more than 2 years after menarche (late group). No significant differences between the early and late groups were found for median age at presentation (30.0 vs 28.0 years), median parity (both 2.0), stillbirth (n=145 [89.5%] vs n=95 [88.0%]), median duration of labor (both 2.0 days), home delivery (n=31 [19.1%] vs n=17 [15.7%]), cesarean delivery (n=79 [48.8%] vs 58 [53.7%]), median time from obstetric fistula formation to presentation (48.0 vs 24.0 months), and obstetric fistula classifications. Obstetric fistula occurred during the first pregnancy in 99 (61.1%) women in the early group and 71 (65.7%) in the late group (P=0.440). Frequency of obstetric fistula during the first pregnancy is not increased among women who experience their first pregnancy within 2 years of menarche. © 2017 International Federation of Gynecology and Obstetrics.

Early Life Adversity during the Infant Sensitive Period for Attachment:, Programming of Behavioral Neurobiology of Threat Processing and Social Behavior

PubMed Central

Opendak, Maya; Gould, Elizabeth; Sullivan, Regina

2017-01-01

Animals, including humans, require a highly coordinated and flexible system of social behavior and threat evaluation. However, trauma can disrupt this system, with the amygdala implicated as a mediator of these impairments in behavior. Recent evidence has further highlighted the context of infant trauma as a critical variable in determining its immediate and enduring consequences, with trauma experienced from an attachment figure, such as occurs in cases of caregiver-child maltreatment, as particularly detrimental. This review focuses on the unique role of caregiver presence during early-life trauma in programming deficits in social behavior and threat processing. Using data primarily from rodent models, we describe the interaction between trauma and attachment during a sensitive period in early life, which highlights the role of the caregiver’s presence in engagement of attachment brain circuitry and suppressing threat processing by the amygdala. These data suggest that trauma experienced directly from an abusive caregiver and trauma experienced in the presence of caregiver cues produce similar neurobehavioral deficits, which are unique from those resulting from trauma alone. We go on to integrate this information into social experience throughout the lifespan, including consequences for complex scenarios, such as dominance hierarchy formation and maintenance. PMID:28254197

Determining Factors and Critical Periods in the Formation of Eating Habits: Results from the Habeat Project.

PubMed

Issanchou, Sylvie

2017-01-01

Eating habits form early during childhood and are likely to track until the beginning of adulthood. Thus, understanding the formation of eating habits is important. Consequently, the population targeted in the European project Habeat comprised infants and young children up to 6 years of age. Habeat mainly focused on the qualitative dimension of eating habits with a particular attention on vegetables and to a lesser extent on fruit. Food intake of young children was also studied in 2 challenging situations where overeating may occur and the relation between children's behaviour and feeding parental practices was examined. Key Messages: Habeat found evidence that breastfeeding may facilitate the consumption of vegetables and fruit and a greater variety of healthy foods in later childhood. Introduction of a variety of vegetables at the beginning of the complementary feeding period increases later acceptance of novel foods. Repeated exposure is a powerful mechanism to increase children's intake of a novel vegetable in infants and young children. Offering energy-dense snacks before or after meals should be avoided. Moreover, food should be offered to children in response to their feelings of hunger, and not used as reward for a good behaviour or for any other reason. © 2017 S. Karger AG, Basel.

Dark-ages reionization and galaxy formation simulation - XIII. AGN quenching of high-redshift star formation in ZF-COSMOS-20115

NASA Astrophysics Data System (ADS)

Qin, Yuxiang; Mutch, Simon J.; Duffy, Alan R.; Geil, Paul M.; Poole, Gregory B.; Mesinger, Andrei; Wyithe, J. Stuart B.

2017-11-01

Massive quiescent galaxies (MQGs) are thought to have formed stars rapidly at early times followed by a long period of quiescence. The recent discovery of a MQG, ZF-COSMOS-20115 at z ˜ 4, only 1.5 Gyr after the big bang, places new constraints on galaxy growth and the role of feedback in early star formation. Spectroscopic follow-up confirmed ZF-COSMOS-20115 as a MQG at z = 3.717 with an estimated stellar mass of ˜1011 M⊙, showing no evidence of recent star formation. We use the Meraxes semi-analytic model to investigate how ZF-COSMOS-20115 analogues build stellar mass, and why they become quiescent. We identify three analogue galaxies with similar properties to ZF-COSMOS-20115. We find that ZF-COSMOS-20115 is likely hosted by a massive halo with virial mass of ˜1013 M⊙, having been through significant mergers at early times. These merger events drove intense growth of the nucleus, which later prevented cooling and quenched star formation. Therefore, ZF-COSMOS-20115 is unlikely to have experienced strong or extended star formation events at z < 3.7. We find that the analogues host the most massive black holes in our simulation and were luminous quasars at z ˜ 5, indicating that ZF-COSMOS-20115 and other MQGs may be the descendants of high-redshift quasars. In addition, the model suggests that ZF-COSMOS-20115 formed in a region of intergalactic medium that was reionized early.

Marketing EPSDT to Clients: A Self-Instructional Module for Early Periodic Screening Diagnosis Treatment.

ERIC Educational Resources Information Center

Simon, John L.; McArdle, Patricia

Early and Periodic Screening, Diagnosis and Treatment (EPSDT) is a program of preventive health services available to individuals under 21 years of age who are eligible for Medicaid benefits. As of July 1, 1973, all states operating a Medicaid program were required to provide EPSDT services to all those eligible. The purpose of this module is to…

Bacterial Selection during the Formation of Early-Stage Aerobic Granules in Wastewater Treatment Systems Operated Under Wash-Out Dynamics

PubMed Central

Weissbrodt, David G.; Lochmatter, Samuel; Ebrahimi, Sirous; Rossi, Pierre; Maillard, Julien; Holliger, Christof

2012-01-01

Aerobic granular sludge is attractive for high-rate biological wastewater treatment. Biomass wash-out conditions stimulate the formation of aerobic granules. Deteriorated performances in biomass settling and nutrient removal during start-up have however often been reported. The effect of wash-out dynamics was investigated on bacterial selection, biomass settling behavior, and metabolic activities during the formation of early-stage granules from activated sludge of two wastewater treatment plants (WWTP) over start-up periods of maximum 60 days. Five bubble-column sequencing batch reactors were operated with feast-famine regimes consisting of rapid pulse or slow anaerobic feeding followed by aerobic starvation. Slow-settling fluffy granules were formed when an insufficient superficial air velocity (SAV; 1.8 cm s−1) was applied, when the inoculation sludge was taken from a WWTP removing organic matter only, or when reactors were operated at 30°C. Fast-settling dense granules were obtained with 4.0 cm s−1 SAV, or when the inoculation sludge was taken from a WWTP removing all nutrients biologically. However, only carbon was aerobically removed during start-up. Fluffy granules and dense granules were displaying distinct predominant phylotypes, namely filamentous Burkholderiales affiliates and Zoogloea relatives, respectively. The latter were predominant in dense granules independently from the feeding regime. A combination of insufficient solid retention time and of leakage of acetate into the aeration phase during intensive biomass wash-out was the cause for the proliferation of Zoogloea spp. in dense granules, and for the deterioration of BNR performances. It is however not certain that Zoogloea-like organisms are essential in granule formation. Optimal operation conditions should be elucidated for maintaining a balance between organisms with granulation propensity and nutrient removing organisms in order to form granules with BNR activities in short

Bacterial Selection during the Formation of Early-Stage Aerobic Granules in Wastewater Treatment Systems Operated Under Wash-Out Dynamics.

PubMed

Weissbrodt, David G; Lochmatter, Samuel; Ebrahimi, Sirous; Rossi, Pierre; Maillard, Julien; Holliger, Christof

2012-01-01

Aerobic granular sludge is attractive for high-rate biological wastewater treatment. Biomass wash-out conditions stimulate the formation of aerobic granules. Deteriorated performances in biomass settling and nutrient removal during start-up have however often been reported. The effect of wash-out dynamics was investigated on bacterial selection, biomass settling behavior, and metabolic activities during the formation of early-stage granules from activated sludge of two wastewater treatment plants (WWTP) over start-up periods of maximum 60 days. Five bubble-column sequencing batch reactors were operated with feast-famine regimes consisting of rapid pulse or slow anaerobic feeding followed by aerobic starvation. Slow-settling fluffy granules were formed when an insufficient superficial air velocity (SAV; 1.8 cm s(-1)) was applied, when the inoculation sludge was taken from a WWTP removing organic matter only, or when reactors were operated at 30°C. Fast-settling dense granules were obtained with 4.0 cm s(-1) SAV, or when the inoculation sludge was taken from a WWTP removing all nutrients biologically. However, only carbon was aerobically removed during start-up. Fluffy granules and dense granules were displaying distinct predominant phylotypes, namely filamentous Burkholderiales affiliates and Zoogloea relatives, respectively. The latter were predominant in dense granules independently from the feeding regime. A combination of insufficient solid retention time and of leakage of acetate into the aeration phase during intensive biomass wash-out was the cause for the proliferation of Zoogloea spp. in dense granules, and for the deterioration of BNR performances. It is however not certain that Zoogloea-like organisms are essential in granule formation. Optimal operation conditions should be elucidated for maintaining a balance between organisms with granulation propensity and nutrient removing organisms in order to form granules with BNR activities in short

Formative Interventions in Leadership Development in Early Childhood Education: The Potential of Double Stimulation

ERIC Educational Resources Information Center

Nuttall, Joce; Thomas, Louise; Henderson, Linda

2018-01-01

This article critiques the usefulness of double stimulation, a key concept in Vygotskian analyses of human development, with leaders in early childhood services in Australia. A series of formative interventions was conducted to identify and address systemic tensions that were confounding leaders' attempts to realise a central object of activity in…

Femtosecond laser-induced periodic surface structural formation on sapphire with nanolayered gold coating

NASA Astrophysics Data System (ADS)

Yin, Kai; Wang, Cong; Duan, Ji'an; Guo, Chunlei

2016-09-01

Sapphire has a potential as a new generation of electronics display. However, direct processing of sapphire surface by visible or near-IR laser light is challenging since sapphire is transparent to these wavelengths. In this study, we investigate the formation of femtosecond laser-induced periodic surface structures (LIPSSs) on sapphire coated with nanolayered gold film. We found a reduced threshold by about 25 % in generating uniform LIPSSs on sapphire due to the nanolayered gold film. Different thickness of nanolayered gold films are studied, and it is shown that the change in thickness does not significantly affect the threshold reduction. It is believed that the diffusion of hot electrons in the gold films increases interfacial carrier density and electron-phonon coupling that results in a reduced threshold and more uniform periodic surface structure generation.

In vivo loss of function study reveals the short stature homeobox-containing (shox) gene plays indispensable roles in early embryonic growth and bone formation in zebrafish.

PubMed

Sawada, Rie; Kamei, Hiroyasu; Hakuno, Fumihiko; Takahashi, Shin-Ichiro; Shimizu, Toshiaki

2015-02-01

Congenital loss of the SHOX gene is considered to be a genetic cause of short stature phenotype in Turner syndrome and Leri-Weill dyschondrosteosis patients. Though SHOX expression initiates during early fetal development, little is known about the embryonic roles of SHOX. The evolutionary conservation of the zebrafish shox gene and the convenience of the early developmental stages for analyses make zebrafish a preferred model. Here, we characterized structure, expression, and developmental roles of zebrafish shox through a loss-of-function approach. We found a previously undiscovered Shox protein that has both a homeodomain and an OAR-domain in zebrafish. The shox transcript emerged during the segmentation period and it increased in later stages. The predominant domains of shox expression were mandibular arch, pectoral fin, anterior notochord, rhombencephalon, and mesencephalon, suggesting that Shox is involved in bone and neural development. Translational blockade of Shox mRNA by an antisense morpholino oligo delayed embryonic growth, which was restored by the co-overexpression of morpholino-resistant Shox mRNA. At later stages, impaired Shox expression markedly delayed the calcification process in the anterior vertebral column and craniofacial bones. Our data demonstrate evolutionarily conserved Shox plays roles in early embryonic growth and in later bone formation. © 2014 Wiley Periodicals, Inc.

Chemical Evolution and the Formation of Dwarf Galaxies in the Early Universe

NASA Astrophysics Data System (ADS)

Cote, Benoit; JINA-CEE, NuGrid, ChETEC

2018-06-01

Stellar abundances in local dwarf galaxies offer a unique window into the nature and nucleosynthesis of the first stars. They also contain clues regarding how galaxies formed and assembled in the early stages of the universe. In this talk, I will present our effort to connect nuclear astrophysics with the field of galaxy formation in order to define what can be learned about galaxy evolution using stellar abundances. In particular, I will describe the current state of our numerical chemical evolution pipeline which accounts for the mass assembly history of galaxies, present how we use high-redshift cosmological hydrodynamic simulations to calibrate our models and to learn about the formation of dwarf galaxies, and address the challenge of identifying the dominant r-process site(s) using stellar abundances.

The formation of magnetite in the early Archean oceans

NASA Astrophysics Data System (ADS)

Li, Yi-Liang; Konhauser, Kurt O.; Zhai, Mingguo

2017-05-01

Banded iron formations (BIFs) are iron- and silica-rich chemical sedimentary rocks that were deposited throughout much of the Precambrian. The biological oxidation of dissolved Fe(II) led to the precipitation of a ferric oxyhydroxide phase, such as ferrihydrite, in the marine photic zone. Upon burial, ferrihydrite was either transformed into hematite through dehydration or it was reduced to magnetite via biological or abiological Fe(III) reduction coupled to the oxidation of buried microbial biomass. However, it has always been intriguing as to why the oldest BIFs are characteristically magnetite-rich, while BIFs formed after the Neoarchean are dominated by hematite. Here, we propose that some magnetite in early Archean BIF could have precipitated directly from seawater through the reaction of settling ferrihydrite and hot, Fe(II)-rich hydrothermal fluids that existed in the deeper waters. We conducted experiments that showed the reaction of Fe(II) with biogenic ferric iron mats under strict anoxic conditions lead to the formation of a metastable green rust phase that within hours transformed into magnetite. Our model further posits that with the progressive cooling and oxidation of the Earth's oceans, the above reaction shuts off, and magnetite was subsequently restricted to reactions associated with diagenesis and metamorphism.

Core formation in the early solar system through percolation: 4-D in-situ visualization of melt migration

NASA Astrophysics Data System (ADS)

Bromiley, G.; Berg, M.; Le Godec, Y.; Mezouar, N.; Atwood, R. C.; Phillipe, J.

2015-12-01

Although core formation was a key stage in the evolution of terrestrial planets, the physical processes which resulted in segregation of iron and silicate remain poorly understood. Formation of a silicate magma oceans provides an obvious mechanism for segregation of core-forming liquids, although recent work has strengthened arguments for a complex, multi-stage model of core formation. Extreme pressure1 and the effects of deformation2 have both been shown to promote percolation of Fe-rich melts in a solid silicate matrix, providing mechanisms for early, low temperature core-formation. However, the efficiency of these processes remains untested and we lack meaningful experimental data on resulting melt segregation velocities. Arguments regarding the efficiency of core formation through percolation of Fe-rich melts in solid silicate are based on simple, empirical models. Here, we review textural evidence from recent experiments which supports early core formation driven by deformation-aided percolation of Fe-rich melts. We then present results of novel in-situ synchrotron studies designed to provide time-resolved 3-D microimaging of percolating melt in model systems under extreme conditions. Under low strain rates characteristic of deformation-aided core formation, segregation of metallic (core-forming) melts by percolation is driven by stress gradients. This is expected to ultimately result in channelization and efficient segregation of melts noted in high-strain, low pressure experiments3. In-situ visualization also demonstrates that percolation of viscous metallic melts is surprisingly rapid. A combination of melt channelization and hydraulic fracture results in rapid, episodic melt migration, even over the limited time scale of experiments. The efficiency of this process depends strongly on the geometry of the melt network and is scaled to grain size in the matrix. We use both in-situ visualization and high-resolution ex-situ analysis to provide accurate

Affiliation, reward, and immune biomarkers coalesce to support social synchrony during periods of bond formation in humans.

PubMed

Ulmer-Yaniv, Adi; Avitsur, Ronit; Kanat-Maymon, Yaniv; Schneiderman, Inna; Zagoory-Sharon, Orna; Feldman, Ruth

2016-08-01

Social bonds are critical for survival and adaptation and periods of bond formation involve reorganization of neurobiological systems as mediated by social behavior. Theoretical accounts and animal studies suggest similarity between parent-infant and pair bonding, a hypothesis not yet directly tested in humans. In this study, we recruited three groups of human adults (N=189); parents who had their firstborn child in the last 4-6months, new lovers who began a romantic relationship within the past 4months, and non-attached singles. We measured plasma oxytocin (OT), beta endorphin (β-End), and interlukin-6 (IL-6), biomarkers of the affiliation, reward, and stress-response systems, and micro-coded gaze and affect synchrony between parents and infants and among new lovers during social interaction. OT significantly increased during periods of parental and romantic bonding and was highest in new lovers. In contrast, IL-6 and β-End were highest in new parents and lowest in singles. Biomarkers became more tightly coupled during periods of bond formation and inter-correlation among hormones was highest during romantic bonding. Structural equation modeling indicated that the effects of IL-6 and β-End on behavioral synchrony were mediated by their impact on OT, highlighting the integrative role of the oxytocinergic system in supporting human social affiliation. Findings suggest that periods of bond formation are accompanied by increased activity, as well as tighter cross-talk among systems underpinning affiliation, reward, and stress management and that research on the multidimensional process of bonding may shed further light on the effects of attachment on health. Copyright © 2016 Elsevier Inc. All rights reserved.

Spectroscopic studies of the fish fossils (Cladocyclus gardneri and Vinctifer comptoni) from the Ipubi Formation of the Cretaceous Period

NASA Astrophysics Data System (ADS)

Sousa Filho, F. E.; da Silva, J. H.; Saraiva, G. D.; Abagaro, B. T. O.; Barros, O. A.; Saraiva, A. A. F.; Viana, B. C.; Freire, P. T. C.

2016-03-01

Fossils are mineralized remains or traces from animals, plants and other organisms aged to about 108 years. The chemical processes of fossilization are dated back from old geological periods on Earth. The understanding of these processes and the structure of the fossils are one of the goals of paleontology and geology in the sedimentary environments. Many researches have tried to unveil details about special kinds of biological samples; however, a lack of data is noticed for various other specimens. This study reports the investigations through infrared spectroscopy, X-ray fluorescence and X-ray diffraction measurements for two types of fish fossils from the Cretaceous Period. The sample of Cladocyclus gardneri and Vinctifer comptoni fossils were collected from the Ipubi Formation, being one of the less studied, among the formations that constitute the important Santana group in the Araripe Basin, Brazil. The results obtained through different techniques, showed that the C. gardneri fish fossil contains hydroxyapatite and calcite as constituents whereas its rock matrix was formed by calcite, quartz and pyrite. Regarding the V. comptoni, the measurements confirmed the presence of hydroxyapatite in the fossil and its rock matrix gypsum, pyrite, quartz and calcite. The above scientific data contributed to the understanding the fossil formation in the Ipubi Formation, an important environment of the Cretaceous Period, which is rich in well-preserved fossils from different species.

Influence of the Saharan Air Layer on Atlantic tropical cyclone formation during the period 1-12 September 2003

NASA Astrophysics Data System (ADS)

Pan, Weiyu; Wu, Liguang; Shie, Chung-Lin

2011-01-01

Atmospheric Infrared Sounder (AIRS) data show that the Saharan air layer (SAL) is a dry, warm, and well-mixed layer between 950 and 500 hPa over the tropical Atlantic, extending westward from the African coast to the Caribbean Sea. The formations of both Hurricane Isabel and Tropical Depression 14 (TD14) were accompanied with outbreaks of SAL air during the period 1-12 September 2003, although TD14 failed to develop into a named tropical cyclone. The influence of the SAL on their formations is investigated by examining data from satellite observations and numerical simulations, in which AIRS data are incorporated into the MM5 model through the nudging technique. Analyses of the AIRS and simulation data suggest that the SAL may have played two roles in the formation of tropical cyclones during the period 1-12 September 2003. First, the outbreaks of SAL air on 3 and 8 September enhanced the transverse-vertical circulation with the rising motion along the southern edge of the SAL and the sinking motion inside the SAL, triggering the development of two tropical disturbances associated with Hurricane Isabel and TD14. Second, in addition to the reduced environmental humidity and enhanced static stability in the lower troposphere, the SAL dry air intruded into the inner region of these tropical disturbances as their cyclonic flows became strong. This effect may have slowed down the formation of Isabel and inhibited TD14 becoming a named tropical cyclone, while the enhanced vertical shear contributed little to tropical cyclone formation during this period. The 48-h trajectory calculations confirm that the parcels from the SAL can be transported into the inner region of an incipient tropical cyclone.

Smectite formation in the presence of sulfuric acid: Implications for acidic smectite formation on early Mars

NASA Astrophysics Data System (ADS)

Peretyazhko, T. S.; Niles, P. B.; Sutter, B.; Morris, R. V.; Agresti, D. G.; Le, L.; Ming, D. W.

2018-01-01

for global-scale smectite formation on Mars via acid-sulfate conditions created by the volcanic outgassing of SO2 in the Noachian and early Hesperian.

The Role of Music Preferences in Early Adolescents' Friendship Formation and Stability

ERIC Educational Resources Information Center

Selfhout, Maarten H. W.; Branje, Susan J. T.; ter Bogt, Tom F. M.; Meeus, Wim H. J.

2009-01-01

The present study examines the role of similarity in music preferences in the formation and discontinuation of friendships over a 1-year period. Questionnaire data were gathered from 283 Dutch same-sex mutual best friends (mean age = 12.97) in two waves with a 1-year interval. Results show consistent evidence for high similarity in specific music…

The Formation and Early Evolution of Embedded Massive Star Clusters

NASA Astrophysics Data System (ADS)

Barnes, Peter

We propose to combine Spitzer, WISE, Herschel, and other archival spacecraft data with an existing ground- and space-based mm-wave to near-IR survey of molecular clouds over a large portion of the Milky Way, in order to systematically study the formation and early evolution of massive stars and star clusters, and provide new observational calibrations for a theoretical paradigm of this key astrophysical problem. Central Objectives: The Galactic Census of High- and Medium-mass Protostars (CHaMP) is a large, unbiased, uniform, and panchromatic survey of massive star and cluster formation and early evolution, covering 20°x6° of the Galactic Plane. Its uniqueness lies in the comprehensive molecular spectroscopy of 303 massive dense clumps, which have also been included in several archival spacecraft surveys. Our objective is a systematic demographic analysis of massive star and cluster formation, one which has not been possible without knowledge of our CHaMP cloud sample, including all clouds with embedded clusters as well as those that have not yet formed massive stars. For proto-clusters deeply embedded within dense molecular clouds, analysis of these space-based data will: 1. Yield a complete census of Young Stellar Objects in each cluster. 2. Allow systematic measurements of embedded cluster properties: spectral energy distributions, luminosity functions, protostellar and disk fractions, and how these vary with cluster mass, age, and density. Combined with other, similarly complete and unbiased infrared and mm data, CHaMP's goals include: 3. A detailed comparison of the embedded stellar populations with their natal dense gas to derive extinction maps, star formation efficiencies and feedback effects, and the kinematics, physics, and chemistry of the gas in and around the clusters. 4. Tying the demographics, age spreads, and timescales of the clusters, based on pre-Main Sequence evolution, to that of the dense gas clumps and Giant Molecular Clouds. 5. A

Long-period variable stars in NGC 147 and NGC 185 - I. Their star formation histories

NASA Astrophysics Data System (ADS)

Hamedani Golshan, Roya; Javadi, Atefeh; van Loon, Jacco Th.; Khosroshahi, Habib; Saremi, Elham

2017-04-01

NGC 147 and NGC 185 are two of the most massive satellites of the Andromeda galaxy (M 31). Close together in the sky, of similar mass and morphological type dE, they possess different amounts of interstellar gas and tidal distortion. The question therefore is, how do their histories compare? Here, we present the first reconstruction of the star formation histories of NGC 147 and NGC 185 using long-period variable stars. These represent the final phase of evolution of low- and intermediate-mass stars at the asymptotic giant branch, when their luminosity is related to their birth mass. Combining near-infrared photometry with stellar evolution models, we construct the mass function and hence the star formation history. For NGC 185, we found that the main epoch of star formation occurred 8.3 Gyr ago, followed by a much lower, but relatively constant star formation rate. In the case of NGC 147, the star formation rate peaked only 7 Gyr ago, staying intense until ˜3 Gyr ago, but no star formation has occurred for at least 300 Myr. Despite their similar masses, NGC 147 has evolved more slowly than NGC 185 initially, but more dramatically in more recent times. This is corroborated by the strong tidal distortions of NGC 147 and the presence of gas in the centre of NGC 185.

Formation and removal of PCDD/Fs in a municipal waste incinerator during different operating periods.

PubMed

Wang, Hou Chuan; Hwang, Jyh Feng; Chi, Kai Hsien; Chang, Moo Been

2007-04-01

The PCDD/F concentrations and removal efficiencies achieved with air pollution control devices (APCDs) during different operating periods (start-up, normal operation, and shut-down) at an existing municipal waste incinerator (MWI) in Taiwan are evaluated via stack sampling and analysis. The MWI investigated is equipped with electrostatic precipitators (EP), wet scrubbers (WS), and selective catalytic reduction system (SCR) as APCDs. The sampling results indicate that the PCDD/F concentrations at the EP inlet during start-up period were 15 times higher than that measured during normal operation period. The PCDD/F concentration observed at shut-down period was close to that measured at normal operation period. The CO concentration was between 400 and 1000 ppm during start-up period, which was about 50 times higher compared with the normal operation. Hence, combustion condition significantly affected the PCDD/F formation concentration during the waste incineration process. In addition, the distributions of the PCDD/F congeners were similar at different operating periods. During the normal operation and shut-down periods, the EP decreases the PCDD/F concentration (based on TEQ) by 18.4-48.6%, while the removal efficiency of PCDD/Fs achieved with SCR system reaches 99.3-99.6%. Nevertheless, the PCDD/F removal efficiency achieved with SCR was only 42% during the 19-h start-up period due to the low SCR operating temperature (195 degrees C).

Dental Ontogeny in Pliocene and Early Pleistocene Hominins

PubMed Central

Smith, Tanya M.; Tafforeau, Paul; Le Cabec, Adeline; Bonnin, Anne; Houssaye, Alexandra; Pouech, Joane; Moggi-Cecchi, Jacopo; Manthi, Fredrick; Ward, Carol; Makaremi, Masrour; Menter, Colin G.

2015-01-01

Until recently, our understanding of the evolution of human growth and development derived from studies of fossil juveniles that employed extant populations for both age determination and comparison. This circular approach has led to considerable debate about the human-like and ape-like affinities of fossil hominins. Teeth are invaluable for understanding maturation as age at death can be directly assessed from dental microstructure, and dental development has been shown to correlate with life history across primates broadly. We employ non-destructive synchrotron imaging to characterize incremental development, molar emergence, and age at death in more than 20 Australopithecus anamensis, Australopithecus africanus, Paranthropus robustus and South African early Homo juveniles. Long-period line periodicities range from at least 6–12 days (possibly 5–13 days), and do not support the hypothesis that australopiths have lower mean values than extant or fossil Homo. Crown formation times of australopith and early Homo postcanine teeth fall below or at the low end of extant human values; Paranthropus robustus dentitions have the shortest formation times. Pliocene and early Pleistocene hominins show remarkable variation, and previous reports of age at death that employ a narrow range of estimated long-period line periodicities, cuspal enamel thicknesses, or initiation ages are likely to be in error. New chronological ages for SK 62 and StW 151 are several months younger than previous histological estimates, while Sts 24 is more than one year older. Extant human standards overestimate age at death in hominins predating Homo sapiens, and should not be applied to other fossil taxa. We urge caution when inferring life history as aspects of dental development in Pliocene and early Pleistocene fossils are distinct from modern humans and African apes, and recent work has challenged the predictive power of primate-wide associations between hominoid first molar emergence and

The formation of periodic micro/nano structured on stainless steel by femtosecond laser irradiation

NASA Astrophysics Data System (ADS)

Yao, Caizhen; Gao, Wei; Ye, Yayun; Jiang, Yong; Xu, Shizhen; Yuan, Xiaodong

2017-07-01

Stainless steel surface was irradiated by linear polarized laser (800 nm, 35 fs, 4 Hz and 0.7 J/cm2) with different pulse numbers. Environmental scanning electron microscope (ESEM/EDS) was used for detailed morphology, microstructure and composition studies. The wettability of irradiated steel surface was tested by Interface Tensiometer JC-2000X and compared with untreated stainless steel. Results showed that micro/nanostripes with different periods were formed. The period increased with the increasing pulse numbers from 450 nm for 90 pulses to 500 nm for 180 pulses. The orientation of those stripes was parallel with the laser beam polarization. Nanoparticles were observed on those periodic structures. EDS indicated that the atomic ratio of Cr increased and the atomic ratios of Fe and Ni decreased after laser irradiation, which may enhance the corrosion resistance due to the Cr-rich layer. The prepared structure exhibited hydrophobic property without further treatment. The formation mechanism of micro/nanoperiodic structures was also explored.

Permian-Early Triassic tectonics and stratigraphy of the Karoo Supergroup in northwestern Mozambique

NASA Astrophysics Data System (ADS)

Bicca, Marcos Müller; Philipp, Ruy Paulo; Jelinek, Andrea Ritter; Ketzer, João Marcelo Medina; dos Santos Scherer, Claiton Marlon; Jamal, Daúd Liace; dos Reis, Adriano Domingos

2017-06-01

The Gondwana continent was the base of great basin inception, sedimentation and magmatism throughout the Cambrian to Middle Jurassic periods. The northwestern Mozambique igneous and metamorphic basement assemblages host the NW-trending Moatize Minjova Basin, which has great economic potential for coal and gas mining. This rift basin was activated by an S-SW stress field during the Early Permian period, as constrained by regional and field scale structural data. Tectonically induced subsidence in the basin, from the reactivation of NW-SE and NNE-SSW regional structures is well recorded by faults, folds and synsedimentary fractures within the Early Late Permian Moatize Formation. NW-SE, N-S and NE-SW field structures consist of post-Karoo reactivation patterns related to a NNE-SSW extension produced by the Pangea breakup and early inception stages of the Great East African Rift System. The Early Late Permian sequences of the Moatize-Minjova Basin are composed of fluvial meandering, coal-bearing beds of the Moatize Formation, which comprises mostly floodplain, crevasse splay and fluvial channel lithofacies associations, deposited in a cyclic pattern. This sequence was overlapped by a multiple-story, braided fluvial plain sequence of the Matinde Formation (Late Permian - Early Triassic). Lithofacies associations in the Matinde Formation and its internal relationships suggest deposition of poorly channelized braided alluvial plain in which downstream and probably lateral accretion macroforms alternate with gravity flow deposits. NW paleoflow measurements suggest that Permian fluvial headwaters were located somewhere southeast of the study area, possibly between the African and Antarctic Precambrian highlands.

Periodic Pattern Formation of Bacterial Colonies

NASA Astrophysics Data System (ADS)

Itoh, Hiroto; Wakita, Jun-ichi; Matsuyama, Tohey; Matsushita, Mitsugu

1999-04-01

We have experimentally investigated pattern formation of colonies ofbacterial species Proteus mirabilis, which is famous forforming concentric-ring-like colonies.The colony grows cyclically with the interface repeating an advance anda stop alternately on a surface of a solid agar medium.We distinguish three phases (initial lag phase, the followingmigration and consolidation phases that appear alternately) for the colony growth.When we cut a colony just behind a migrating front shortly after the migrationstarted, the migration ended earlier and the following consolidationlasted longer.However, the following cycles were not influenced by the cut, i.e., thephases of the migration and consolidation were not affected.Global chemical signals governing the colony formation from thecenter were not found to exist.We also quantitatively checked phase entrainment by letting two coloniescollide with each other and found that it does not take place in macroscopic scales.All these experimental results suggest that the most important factorfor the migration is the cell population density.

Exploring the dusty star-formation in the early Universe using intensity mapping

NASA Astrophysics Data System (ADS)

Lagache, Guilaine

2018-05-01

In the last decade, it has become clear that the dust-enshrouded star formation contributes significantly to early galaxy evolution. Detection of dust is therefore essential in determining the properties of galaxies in the high-redshift universe. This requires observations at the (sub-)millimeter wavelengths. Unfortunately, sensitivity and background confusion of single dish observations on the one hand, and mapping efficiency of interferometers on the other hand, pose unique challenges to observers. One promising route to overcome these difficulties is intensity mapping of fluctuations which exploits the confusion-limited regime and measures the collective light emission from all sources, including unresolved faint galaxies. We discuss in this contribution how 2D and 3D intensity mapping can measure the dusty star formation at high redshift, through the Cosmic Infrared Background (2D) and [CII] fine structure transition (3D) anisotropies.

Late Tharsis formation and implications for early Mars

NASA Astrophysics Data System (ADS)

Bouley, Sylvain; Baratoux, David; Matsuyama, Isamu; Forget, Francois; Séjourné, Antoine; Turbet, Martin; Costard, Francois

2016-03-01

The Tharsis region is the largest volcanic complex on Mars and in the Solar System. Young lava flows cover its surface (from the Amazonian period, less than 3 billion years ago) but its growth started during the Noachian era (more than 3.7 billion years ago). Its position has induced a reorientation of the planet with respect to its spin axis (true polar wander, TPW), which is responsible for the present equatorial position of the volcanic province. It has been suggested that the Tharsis load on the lithosphere influenced the orientation of the Noachian/Early Hesperian (more than 3.5 billion years ago) valley networks and therefore that most of the topography of Tharsis was completed before fluvial incision. Here we calculate the rotational figure of Mars (that is, its equilibrium shape) and its surface topography before Tharsis formed, when the spin axis of the planet was controlled by the difference in elevation between the northern and southern hemispheres (hemispheric dichotomy). We show that the observed directions of valley networks are also consistent with topographic gradients in this configuration and thus do not require the presence of the Tharsis load. Furthermore, the distribution of the valleys along a small circle tilted with respect to the equator is found to correspond to a southern-hemisphere latitudinal band in the pre-TPW geographical frame. Preferential accumulation of ice or water in a south tropical band is predicted by climate model simulations of early Mars applied to the pre-TPW topography. A late growth of Tharsis, contemporaneous with valley incision, has several implications for the early geological history of Mars, including the existence of glacial environments near the locations of the pre-TPW poles of rotation, and a possible link between volcanic outgassing from Tharsis and the stability of liquid water at the surface of Mars.

Late Tharsis formation and implications for early Mars.

PubMed

Bouley, Sylvain; Baratoux, David; Matsuyama, Isamu; Forget, Francois; Séjourné, Antoine; Turbet, Martin; Costard, Francois

2016-03-17

The Tharsis region is the largest volcanic complex on Mars and in the Solar System. Young lava flows cover its surface (from the Amazonian period, less than 3 billion years ago) but its growth started during the Noachian era (more than 3.7 billion years ago). Its position has induced a reorientation of the planet with respect to its spin axis (true polar wander, TPW), which is responsible for the present equatorial position of the volcanic province. It has been suggested that the Tharsis load on the lithosphere influenced the orientation of the Noachian/Early Hesperian (more than 3.5 billion years ago) valley networks and therefore that most of the topography of Tharsis was completed before fluvial incision. Here we calculate the rotational figure of Mars (that is, its equilibrium shape) and its surface topography before Tharsis formed, when the spin axis of the planet was controlled by the difference in elevation between the northern and southern hemispheres (hemispheric dichotomy). We show that the observed directions of valley networks are also consistent with topographic gradients in this configuration and thus do not require the presence of the Tharsis load. Furthermore, the distribution of the valleys along a small circle tilted with respect to the equator is found to correspond to a southern-hemisphere latitudinal band in the pre-TPW geographical frame. Preferential accumulation of ice or water in a south tropical band is predicted by climate model simulations of early Mars applied to the pre-TPW topography. A late growth of Tharsis, contemporaneous with valley incision, has several implications for the early geological history of Mars, including the existence of glacial environments near the locations of the pre-TPW poles of rotation, and a possible link between volcanic outgassing from Tharsis and the stability of liquid water at the surface of Mars.

Risk of Porphyromonas gingivalis recolonization during the early period of periodontal maintenance in initially severe periodontitis sites.

PubMed

Fujise, Osamu; Miura, Mayumi; Hamachi, Takafumi; Maeda, Katsumasa

2006-08-01

Porphyromonas gingivalis is considered a critical pathogen of periodontal diseases including recurrent periodontitis. The profound effects of active periodontal treatment (APT) on P. gingivalis elimination were previously demonstrated and revealed that the subsequent P. gingivalis-free or -suppressed status seems to be maintained during early periodontal maintenance (PMT). The aim of the present study was to show the occurrence of microbial recolonization during this early PMT period. In total, 128 sites from 11 generalized chronic periodontitis patients and one generalized aggressive periodontitis patient underwent clinical and microbiologic examination at baseline (Exam-I), after APT (Exam-II), and in PMT (Exam-III). Exam-III was carried out an average of 4.5 +/- 3.5 months after Exam-II. Detection and quantification of putative pathogens were performed using a polymerase chain reaction-based method. The PMT used was effective in maintaining the clinical conditions improved by APT. However, in microbiological examinations, Exam-III showed higher detection frequency and levels of P. gingivalis than Exam-II. This suggests that a P. gingivalis recolonization started in the early PMT period. P. gingivalis-increased sites then showed significantly more severe signs of periodontitis in Exam-I than P. gingivalis-stable sites (bleeding on probing frequency: 76.7% versus 56.5%; suppuration frequency: 41.9% versus 12.9%). On the other hand, in Exam-II, no significant differences of clinical parameters were noted between P. gingivalis-increased and -stable sites. Severe periodontitis sites before APT seemed to place them at risk of P. gingivalis recolonization in the early PMT period, and this microbial restoration could be a cause of recurrent periodontitis.

Is the Predictability of New-Onset Postpartum Depression Better During Pregnancy or in the Early Postpartum Period? A Prospective Study in Croatian Women.

PubMed

Nakić Radoš, Sandra; Herman, Radoslav; Tadinac, Meri

2016-01-01

The researchers' aim was to examine whether it was better to predict new-onset postpartum depression (PPD) during pregnancy or immediately after childbirth. A prospective study conducted in Croatia followed women (N = 272) from the third trimester of pregnancy through the early postpartum period (within the first 3 postpartum days), to 6 weeks postpartum. Questionnaires on depression, anxiety, stress, coping, self-esteem, and social support were administered. Through regression analyses we showed that PPD symptoms could be equally predicted by variables from pregnancy (30.3%) and the early postpartum period (34.0%), with a small advantage of PPD prediction in the early postpartum period.

Growth in early life and the development of obesity by age 9 years: are there critical periods and a role for an early life stressor?

PubMed

Giles, L C; Whitrow, M J; Rumbold, A R; Davies, C E; de Stavola, B; Pitcher, J B; Davies, M J; Moore, V M

2013-04-01

Rapid growth, possibly occurring in critical periods in early life, may be important for the development of obesity. It is unknown whether this is influenced by postnatal exposures such as age-relevant sources of stress. Frequent house moves may be one such stressor. We aimed to examine if there is a period of growth in early life critical for the development of child obesity by age 9 years and assess the role of house moves in modifying any relationships between early life growth and obesity at age 9 years. Prospective Australian birth cohort study. In all, 392 children with serial body size measurements from birth to age 9 years. Standardized body mass index (z-BMI) was available for six time points (spanning birth to 3½ years), and the total number of house moves between birth and 3½ years. The outcomes considered were z-BMI and % body fat (%BF) at age 9 years. Linear regression models were used to estimate the effects of serial measurements of z-BMI and number of house moves on the outcomes. Life-course plots showed that z-BMI at 3½ years was a statistically significant predictor of z-BMI at 9 years (β=0.80; standard error (s.e.), 0.04), whereas z-BMI at 9 months (β=-1.13; s.e., 0.40) and 3½ years (β=4.82; s.e., 0.42) were significant predictors of %BF at age 9 years. There were statistically significant interactions between the number of house moves and change in z-BMI between 9 and 12 months, such that ≥ 3 house moves in early life amplified the detrimental effects of earlier rapid growth on both body size and composition at age 9 years. In the absence of evidence for a single critical period, efforts to prevent overweight and obesity are required throughout childhood. In addition, modifiable postnatal stressors may exacerbate effects of early growth on obesity in later childhood.

Parents’ Marital Distress, Divorce, and Remarriage: Links with Daughters’ Early Family Formation Transitions

PubMed Central

Amato, Paul R.; Kane, Jennifer B.

2011-01-01

We used data from the Add Health study to estimate the effects of parents’ marital status and relationship distress on daughters’ early family formation transitions. Outcomes included traditional transitions (marriage and marital births) and nontraditional transitions (cohabitation and nonmarital births). Relationship distress among continuously married parents was not related to any outcome. Offspring with single parents and remarried parents had an elevated risk of nonmarital births and nonmarital cohabitation. Offspring with remarried parents with a high-distress relationship had an elevated risk of early marriages and marital births. These results, combined with analyses of mediating variables, provide the strongest support for a modeling perspective, although some support also was found for a perspective based on escape from stress. PMID:21785523

Regulation of endoderm formation and left-right asymmetry by miR-92 during early zebrafish development

PubMed Central

Li, Nan; Wei, Chunyao; Olena, Abigail F.; Patton, James G.

2011-01-01

microRNAs (miRNAs) are a family of 21-23 nucleotide endogenous non-coding RNAs that post-transcriptionally regulate gene expression in a sequence-specific manner. Typically, miRNAs downregulate target genes by recognizing and recruiting protein complexes to 3′UTRs, followed by translation repression or mRNA degradation. miR-92 is a well-studied oncogene in mammalian systems. Here, using zebrafish as a model system, we uncovered a novel tissue-inductive role for miR-92 during early vertebrate development. Overexpression resulted in reduced endoderm formation during gastrulation with consequent cardia and viscera bifida. By contrast, depletion of miR-92 increased endoderm formation, which led to abnormal Kupffer's vesicle development and left-right patterning defects. Using target prediction algorithms and reporter constructs, we show that gata5 is a target of miR-92. Alteration of gata5 levels reciprocally mirrored the effects of gain and loss of function of miR-92. Moreover, genetic epistasis experiments showed that miR-92-mediated defects could be substantially suppressed by modulating gata5 levels. We propose that miR-92 is a critical regulator of endoderm formation and left-right asymmetry during early zebrafish development and provide the first evidence for a regulatory function for gata5 in the formation of Kupffer's vesicle and left-right patterning. PMID:21447552

Spectroscopic studies of the fish fossils (Cladocyclus gardneri and Vinctifer comptoni) from the Ipubi Formation of the Cretaceous Period.

PubMed

Sousa Filho, F E; da Silva, J H; Saraiva, G D; Abagaro, B T O; Barros, O A; Saraiva, A A F; Viana, B C; Freire, P T C

2016-03-15

Fossils are mineralized remains or traces from animals, plants and other organisms aged to about 10(8)years. The chemical processes of fossilization are dated back from old geological periods on Earth. The understanding of these processes and the structure of the fossils are one of the goals of paleontology and geology in the sedimentary environments. Many researches have tried to unveil details about special kinds of biological samples; however, a lack of data is noticed for various other specimens. This study reports the investigations through infrared spectroscopy, X-ray fluorescence and X-ray diffraction measurements for two types of fish fossils from the Cretaceous Period. The sample of Cladocyclus gardneri and Vinctifer comptoni fossils were collected from the Ipubi Formation, being one of the less studied, among the formations that constitute the important Santana group in the Araripe Basin, Brazil. The results obtained through different techniques, showed that the C. gardneri fish fossil contains hydroxyapatite and calcite as constituents whereas its rock matrix was formed by calcite, quartz and pyrite. Regarding the V. comptoni, the measurements confirmed the presence of hydroxyapatite in the fossil and its rock matrix gypsum, pyrite, quartz and calcite. The above scientific data contributed to the understanding the fossil formation in the Ipubi Formation, an important environment of the Cretaceous Period, which is rich in well-preserved fossils from different species. Copyright © 2015 Elsevier B.V. All rights reserved.

Borderline Personality Disorder in the perinatal period: early infant and maternal outcomes.

PubMed

Blankley, Gaynor; Galbally, Megan; Snellen, Martien; Power, Josephine; Lewis, Andrew J

2015-12-01

This study examines pregnancy and early infant outcomes of pregnant women with a clinical diagnosis of Borderline Personality Disorder presenting for obstetric services to a major metropolitan maternity hospital in Victoria, Australia. A retrospective case review of pregnancy and early infant outcomes on 42 women who had been diagnosed with Borderline Personality Disorder via psychiatric assessment using DSM-IV-R criteria was undertaken. Outcomes were compared with a control group of 14,313 consisting of women and infants of non-affected women from the same hospital over the same period of time. Women presenting for obstetric services with a clinical diagnosis of Borderline Personality Disorder experienced considerable psychosocial impairment. They anticipated birth as traumatic and frequently requested early delivery. High comorbidity with substance abuse was found and high rates of referral to child protective services. Mothers with Borderline Personality Disorder were significantly more likely to have negative birth outcomes such as lowered Apgar scores, prematurity and special care nursery referral when compared with controls. These findings offer preliminary evidence to be considered by clinicians in developing treatments and services for the perinatal care of women with Borderline Personality Disorder and their infants. Further research is required in order to develop evidence informed clinical guidelines for the management of women with Borderline Personality Disorder and their infants. © The Royal Australian and New Zealand College of Psychiatrists 2015.

Spatially-resolved star formation histories of CALIFA galaxies. Implications for galaxy formation

NASA Astrophysics Data System (ADS)

González Delgado, R. M.; Pérez, E.; Cid Fernandes, R.; García-Benito, R.; López Fernández, R.; Vale Asari, N.; Cortijo-Ferrero, C.; de Amorim, A. L.; Lacerda, E. A. D.; Sánchez, S. F.; Lehnert, M. D.; Walcher, C. J.

2017-11-01

This paper presents the spatially resolved star formation history (SFH) of nearby galaxies with the aim of furthering our understanding of the different processes involved in the formation and evolution of galaxies. To this end, we apply the fossil record method of stellar population synthesis to a rich and diverse data set of 436 galaxies observed with integral field spectroscopy in the CALIFA survey. The sample covers a wide range of Hubble types, with stellar masses ranging from M⋆ 109 to 7 × 1011 M⊙. Spectral synthesis techniques are applied to the datacubes to retrieve the spatially resolved time evolution of the star formation rate (SFR), its intensity (ΣSFR), and other descriptors of the 2D SFH in seven bins of galaxy morphology (E, S0, Sa, Sb, Sbc, Sc, and Sd) and five bins of stellar mass. Our main results are that (a) galaxies form very fast independently of their current stellar mass, with the peak of star formation at high redshift (z > 2). Subsequent star formation is driven by M⋆ and morphology, with less massive and later type spirals showing more prolonged periods of star formation. (b) At any epoch in the past, the SFR is proportional to M⋆, with most massive galaxies having the highest absolute (but lowest specific) SFRs. (c) While today, the ΣSFR is similar for all spirals and significantly lower in early-type galaxies (ETG), in the past, the ΣSFR scales well with morphology. The central regions of today's ETGs are where the ΣSFR reached the highest values (> 103 M⊙ Gyr-1 pc-2), similar to those measured in high-redshift star-forming galaxies. (d) The evolution of ΣSFR in Sbc systems matches that of models for Milky Way-like galaxies, suggesting that the formation of a thick disk may be a common phase in spirals at early epochs. (e) The SFR and ΣSFR in outer regions of E and S0 galaxies show that they have undergone an extended phase of growth in mass between z = 2 and 0.4. The mass assembled in this phase is in agreement with

Liquid Crystal Enabled Early Stage Detection of Beta Amyloid Formation on Lipid Monolayers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadati, Monirosadat; Apik, Aslin Izmitli; Armas-Perez, Julio C.

2015-09-09

Liquid crystals (LCs) can serve as sensitive reporters of interfacial events, and this property has been used for sensing of synthetic or biological toxins. Here it is demonstrated that LCs can distinguish distinct molecular motifs and exhibit a specific response to beta-sheet structures. That property is used to detect the formation of highly toxic protofibrils involved in neurodegenerative diseases, where it is crucial to develop methods that probe the early-stage aggregation of amyloidogenic peptides in the vicinity of biological membranes. In the proposed method, the amyloid fibrils formed at the lipid-decorated LC interface can change the orientation of LCs andmore » form elongated and branched structures that are amplified by the mesogenic medium; however, nonamyloidogenic peptides form ellipsoidal domains of tilted LCs. Moreover, a theoretical and computational analysis is used to reveal the underlying structure of the LC, thereby providing a detailed molecular-level view of the interactions and mechanisms responsible for such motifs. The corresponding signatures can be detected at nanomolar concentrations of peptide by polarized light microscopy and much earlier than the ones that can be identified by fluorescence-based techniques. As such, it offers the potential for early diagnoses of neurodegenerative diseases and for facile testing of inhibitors of amyloid formation.« less

Formation mechanism of self-assembled polarization-dependent periodic nanostructures in β-Ga2O3

NASA Astrophysics Data System (ADS)

Nakanishi, Y.; Shimotsuma, Y.; Sakakura, M.; Shimizu, M.; Miura, K.

2018-02-01

We have successfully observed self-assembled periodic nanostructures inside Si single crystal and GaP crystal, by the femtosecond double-pulse irradiation. These results experimentally indicate that the self-assembly of the periodic nanostructures inside semiconductors triggered by ultrashort pulses irradiation are possibly associated with a direct or an indirect band gap. More recently we have also empirically classified the photoinduced bulk nanogratings into the following three types: (1) structural deficiency, (2) compressed structure, (3) partial crystallization. We have still a big question about what material properties are involved in the bulk nanograting structure formation. In this study, to expand the selectivity of the material for bulk nanograting formation, we have employed β-Ga2O3 crystals (indirect bandgap Eg 4.8 eV) as a sample for femtosecond laser irradiation. The nanograting structure inside β-Ga2O3 crystal was aligned perpendicular to the laser polarization direction. Such phenomenon is similar to the nanograting in SiO2 glass (Eg 9 eV). Moreover, to clarify the band structure, we have also investigate the photoinduced structure in Sn doped β-Ga2O3 crystals, which exhibit direct bandgap according to the first principle calculation.

The formation of magnetite in the early Archean oceans

NASA Astrophysics Data System (ADS)

Li, Y. L.

2017-12-01

Banded iron formations are iron- and silica-rich chemical sedimentary rocks that were deposited throughout much of the Precambrian. It is generally accepted that biological oxidation of dissolved Fe(II) led to the precipitation of a ferric oxyhydroxide phase, such as ferrihydrite, in the marine photic zone. Upon burial, ferrihydrite was either transformed into hematite through dehydration or it was reduced to magnetite via biological or abiological Fe(III) reduction coupled to the oxidation of buried microbial biomass. However, it has always been intriguing as to why the oldest BIFs are characteristically magnetite-rich, while BIFs formed after the Neoarchean are dominated by hematite. Here, we propose that some magnetite in early Archean BIF could have precipitated directly from seawater through the reaction of settling ferrihydrite and hot, Fe(II)-rich hydrothermal fluids that vented directly into the photic zone. We conducted experiments that showed the reaction of Fe(II) with biogenic ferric iron mats under strict anoxic conditions led to the formation of a metastable green rust phase that within hours transformed into magnetite at relatively high temperatures. At lower temperatures magnetite does not form. Our model further posits that with the progressive cooling of the Earth's oceans through Archean, the above reaction shut off, and magnetite was subsequently restricted to reactions associated with diagenesis and metamorphism.

Early social networks predict survival in wild bottlenose dolphins.

PubMed

Stanton, Margaret A; Mann, Janet

2012-01-01

A fundamental question concerning group-living species is what factors influence the evolution of sociality. Although several studies link adult social bonds to fitness, social patterns and relationships are often formed early in life and are also likely to have fitness consequences, particularly in species with lengthy developmental periods, extensive social learning, and early social bond-formation. In a longitudinal study of bottlenose dolphins (Tursiops sp.), calf social network structure, specifically the metric eigenvector centrality, predicted juvenile survival in males. Additionally, male calves that died post-weaning had stronger ties to juvenile males than surviving male calves, suggesting that juvenile males impose fitness costs on their younger counterparts. Our study indicates that selection is acting on social traits early in life and highlights the need to examine the costs and benefits of social bonds during formative life history stages.

Early formation of preferential flow in a homogeneous snowpack observed by micro-CT

NASA Astrophysics Data System (ADS)

Avanzi, Francesco; Petrucci, Giacomo; Matzl, Margret; Schneebeli, Martin; De Michele, Carlo

2017-05-01

We performed X-ray microtomographic observations of wet-snow metamorphism during controlled continuous melting and melt-freeze events in the laboratory. Three blocks of snow were sieved into boxes and subjected to cyclic, superficial heating or heating-cooling to reproduce vertical water infiltration patterns in snow similarly to natural conditions. Periodically, samples were taken at different heights and scanned. Results suggest that wet-snow metamorphism dynamics are highly heterogeneous even in an initially homogeneous snowpack. Consistent with previous work, we observed an increase with time in the thickness of the ice structure, which is a measure of grain size. However, this was coupled with large temporal scatter between consecutive measurements of the specific surface area and of the statistical moments of grain thickness distributions. Because of marked differences in the right tail, grain thickness distributions did not show shape invariance with time, contrary to previous analyses. In our experiments, wet-snow metamorphism showed two strikingly different patterns: homogeneous coarsening superimposed by faster heterogeneous coarsening in areas that were affected by preferential percolation of water. Liquid water movement in snow and fast structural evolution may be thus intrinsically coupled by early formation of preferential flow at local scale. These observations suggest that further experiments are highly needed to fully understand wet-snow metamorphism and infiltration patterns in a natural snowpack.

Effect of bed exercises and gum chewing on abdominal sounds, flatulence and early discharge in the early period after caesarean section.

PubMed

Çevik, Semra Akköz; Başer, Mürüvvet

2016-05-01

The purpose of this study was to determine the effects of bed exercises and gum chewing on abdominal sounds, flatulence and early discharge on women who have given birth at the Cengiz Gökçek Gynecology and Obstetrics Hospital surgery services in Gaziantep city centre. Caesarean operation is the most significant surgical intervention that affects central nervous system and decelerates bowel movements in the postoperative period. Conducted studies show that practices such as gum chewing ensure that bowel functions start in a short time through early feeding and mobilisation and shorten the duration of hospital stay. A randomised controlled experimental was used. A total of 120 women participated in the study in three groups of 40 for gum, exercise and control groups. Gum was given to the groups in the gum section two hours after the ceasarean, the women chewed gum for the first eight hours until flatulence for 15 minutes every two hours. However, the women in the exercise group started moving two hours after the caesarean for the first eight hours until flatulence for five minutes every two hours. The control group consisted of women under routine treatment and care of the hospital. All women were hourly evaluated in terms of abdominal sounds, flatulence and defaecation. It was determined that following caesarean, bowel functions started in three groups at the same time, there was no significant difference between three groups. It was determined that the gum group, exercise group and the control group were discharged earlier, there was no significant difference between three groups The study results show that spinal anaesthesia have positive effects on discharge time after caesarean section operation. This study provides useful information to clinician and researchers when determining practices such as postoperative standing up in early period, gum chewing and early liquid intake related to postoperative bowel functions after abdominal operations. © 2016 John

Time-resolved measurement of single pulse femtosecond laser-induced periodic surface structure formation induced by a pre-fabricated surface groove.

PubMed

Kafka, K R P; Austin, D R; Li, H; Yi, A Y; Cheng, J; Chowdhury, E A

2015-07-27

Time-resolved diffraction microscopy technique has been used to observe the formation of laser-induced periodic surface structures (LIPSS) from the interaction of a single femtosecond laser pulse (pump) with a nano-scale groove mechanically formed on a single-crystal Cu substrate. The interaction dynamics (0-1200 ps) was captured by diffracting a time-delayed, frequency-doubled pulse (probe) from nascent LIPSS formation induced by the pump with an infinity-conjugate microscopy setup. The LIPSS ripples are observed to form asynchronously, with the first one forming after 50 ps and others forming sequentially outward from the groove edge at larger time delays. A 1-D analytical model of electron heating including both the laser pulse and surface plasmon polariton excitation at the groove edge predicts ripple period, melt spot diameter, and qualitatively explains the asynchronous time-evolution of LIPSS formation.

Tetrapod trackways from the early Middle Devonian period of Poland.

PubMed

Niedźwiedzki, Grzegorz; Szrek, Piotr; Narkiewicz, Katarzyna; Narkiewicz, Marek; Ahlberg, Per E

2010-01-07

The fossil record of the earliest tetrapods (vertebrates with limbs rather than paired fins) consists of body fossils and trackways. The earliest body fossils of tetrapods date to the Late Devonian period (late Frasnian stage) and are preceded by transitional elpistostegids such as Panderichthys and Tiktaalik that still have paired fins. Claims of tetrapod trackways predating these body fossils have remained controversial with regard to both age and the identity of the track makers. Here we present well-preserved and securely dated tetrapod tracks from Polish marine tidal flat sediments of early Middle Devonian (Eifelian stage) age that are approximately 18 million years older than the earliest tetrapod body fossils and 10 million years earlier than the oldest elpistostegids. They force a radical reassessment of the timing, ecology and environmental setting of the fish-tetrapod transition, as well as the completeness of the body fossil record.

Periodic Colony Formation of Bacteria Due to their Cell Reproduction and Movement

NASA Astrophysics Data System (ADS)

Itoh, H.; Wakita, J.; Watanabe, K.; Matsuyama, T.; Matsushita, M.

We have experimentally investigated periodic pattern formation produced by bacterial species Proteus mirabilis, which forms concentric-ring-like colonies by repeating migration and rest alternately on the surface of a solid agar medium. We distinguish three phases (initial lag phase, the following migration and consolidation phases that appear alternately) for the colony growth. Here we mainly used physical approaches in order to try to understand the formation of concentric-ring-like colonies, such as cutting the part of a colony during its growth. Global chemical signals governing the colony formation from the center were not found. We also checked phase entrainment quantitatively by letting two colonies collide with each other and confirmed that it does not take place in macroscopic scales. When we cut a colony just behind the migrating front shortly after the migration started, the migration ended earlier and the following consolidation lasted longer. However, the following cycles were not influenced by the cut, i.e., the following migration and consolidation phases were both found to return normal. The cut results in the stop of supply of cell population to the migrating front by internal waves. In fact the cell population on the new terrace during the first migration after the cut was less than that without cut. Furthermore, the cell population density was found to be recovered to the ordinary value by the end of the consolidation. All these experimental results suggest that the most important factor for the repetition of migration and consolidation phases is the cell population density.

Laser induced periodic surface structure formation in germanium by strong field mid IR laser solid interaction at oblique incidence.

PubMed

Austin, Drake R; Kafka, Kyle R P; Trendafilov, Simeon; Shvets, Gennady; Li, Hui; Yi, Allen Y; Szafruga, Urszula B; Wang, Zhou; Lai, Yu Hang; Blaga, Cosmin I; DiMauro, Louis F; Chowdhury, Enam A

2015-07-27

Laser induced periodic surface structures (LIPSS or ripples) were generated on single crystal germanium after irradiation with multiple 3 µm femtosecond laser pulses at a 45° angle of incidence. High and low spatial frequency LIPSS (HSFL and LSFL, respectively) were observed for both s- and p-polarized light. The measured LSFL period for p-polarized light was consistent with the currently established LIPSS origination model of coupling between surface plasmon polaritons (SPP) and the incident laser pulses. A vector model of SPP coupling is introduced to explain the formation of s-polarized LSFL away from the center of the damage spot. Additionally, a new method is proposed to determine the SPP propagation length from the decay in ripple depth. This is used along with the measured LSFL period to estimate the average electron density and Drude collision time of the laser-excited surface. Finally, full-wave electromagnetic simulations are used to corroborate these results while simultaneously offering insight into the nature of LSFL formation.

High resolution imaging studies into the formation of laser-induced periodic surface structures.

PubMed

Kerr, N C; Clark, S E; Emmony, D C

1989-09-01

We report the results of an investigation into the formation mechanism of laser-induced ripple structures based on obtaining direct images of a surface while the transient heating induced by a KrF excimer laser is still present. These images reveal transient but well-defined periodic heating patterns which, if enough subsequent excimer pulses are incident on the surface, become permanently induced ripple structures. It is evident from these transient images that the surface heating is confined to the induced structures, thus strongly supporting the idea that at low fluences the ripples are formed by localizing surface melting.

[Geomagnetic field variations in the human prenatal period and cancer in adults].

PubMed

Iamshanov, V A

2007-01-01

Our earlier evidence pointed to a relationship between geomagnetic field (GMF) variations in pre- and early postnatal periods and appearance in the future of oncopathology in these patients. It appears to contribute to risk for such malignancies in adults as breast, lung, liver, bladder, kidney, prostate, hypophysis cancer, ovarian carcinoma, skin melanoma, Hodgkin's disease, lymphoma, and probably stomach cancer. No link was detected between esophageal, thyroid, colorectal cancer or cervical carcinoma, on the one hand, and GMF variations in prenatal period, on the other. It is suggested that low intensity of GMF is associated with increased death of macrophages and other granulocytes as well as nitric oxide formation both in fetal and maternal organism. The latter factor induces genes responsible for detoxication. In adults, under normal or disturbed GMF conditions, detoxication processes take care of excessive blood-nitric oxide. Both in fetus and mother, due to high GMF intensity, granulocyte decay is inhibited thus causing nitric oxide levels to fall. As a consequence, detoxication fails. That accounts for excessive blood-nitric oxide formation at adult stage when GMF intensity is low or normal. Nitric oxide causes certain nitrosamines to form, which are tissue-specific carcinogens. Therefore, the lower level of GMF oscillations was in pre- and early postnatal periods than in more late terms tumors appeared (for example, the negative correlation for breast cancer took place).

Effect of oxygen plasma etching on pore size-controlled 3D polycaprolactone scaffolds for enhancing the early new bone formation in rabbit calvaria.

PubMed

Kook, Min-Suk; Roh, Hee-Sang; Kim, Byung-Hoon

2018-05-02

This study was to investigate the effects of O 2 plasma-etching of the 3D polycaprolactone (PCL) scaffold surface on preosteoblast cell proliferation and differentiation, and early new bone formation. The PCL scaffolds were fabricated by 3D printing technique. After O 2 plasma treatment, surface characterizations were examined by scanning electron microscopy, atomic force microscopy, and contact angle. MTT assay was used to determine cell proliferation. To investigate the early new bone formation, rabbits were sacrificed at 2 weeks for histological analyses. As the O 2 plasma etching time is increased, roughness and hydrophilicity of the PCL scaffold surface increased. The cell proliferation and differentiation on plasma-etched samples was significantly increased than on untreated samples. At 2 weeks, early new bone formation in O 2 plasma-etched PCL scaffolds was the higher than that of untreated scaffolds. The O 2 plasma-etched PCL scaffolds showed increased preosteoblast differentiation as well as increased new bone formation.

On the correlation between the recent star formation rate in the Solar Neighbourhood and the glaciation period record on Earth

NASA Astrophysics Data System (ADS)

de la Fuente Marcos, R.; de la Fuente Marcos, C.

2004-11-01

Shaviv [New Astron. 8 (2003) 39; J. Geophys. Res. 108 (2003) 3] has shown evidence for a correlation between variations in the Galactic cosmic ray flux reaching Earth and the glaciation period record on Earth during the last 2 Gyr. If the flux of cosmic rays is mainly the result of Type II supernovae, an additional correlation between the star formation history of the Solar Neighbourhood and the timing of past ice ages is expected. Higher star formation rate implies increased cosmic ray flux and this may translate into colder climate through a rise in the average low altitude cloud cover. Here we reanalyze the correlation between this star formation history and the glaciation period record on Earth using a volume limited open cluster sample. Numerical modeling and recent observational data indicate that the correlation is rather strong but only if open clusters within 1.5 kpc from the Sun are considered. Under this constraint, our statistical analysis not only suggests a strong correlation in the timing of the events (enhanced star formation and glaciation episodes), but also in the severity and length of the episodes. In particular, the snowball Earth scenario appears to be connected with the strongest episode of enhanced star formation recorded in the Solar Neighbourhood during the last 2 Gyr.

[Angiopoietins predict long-term outcomes after aneurysmal subarachnoid hemorrhage during an early period].

PubMed

Wang, Yi; Wang, Dong; Wei, Huijie; Tian, Ye; Jiang, Rongcai; Yue, Shuyuan; Zhang, Jianning

2015-05-19

To evaluate the association between serum levels of angiopoietins (Ang) during an early period (within 72 h) and clinical outcomes after aneurysmal subarachnoid haemorrhage (aSAH). This prospective study was conducted at Department of Neurosurgery, Tianjin Medical University General Hospital. Blood samples from 37 aSAH patients were collected at 8 h (or < 8 h), 24 h, 72 h after an onset of SAH. The serum levels of Ang-1, Ang-2 and Tie-2 were measured by enzyme-linked immunosorbent assay (ELISA). They were followed up for 3 months by Glasgow outcome score extended (GOSE). Those with GOSE > 5 were counted as a good outcome while those with GOSE ≤ 5 had a poor outcome. A total of 37 patients with aSAH and 39 healthy controls (HC) were enrolled. The aSAH patients showed a significant rise of Ang-1 within 8 h as compared with HC. The outcomes were good (n = 15) and poor (n = 22). Serum Ang-1 at 8 h (or < 8 h), 24 h and 72 h in good outcomers showed significantly higher than that in poor outcomers [(52 ± 24) vs (37 ± 17) mg/L, (62 ± 26) vs (45 ± 17) mg/L, (107 ± 27) vs (72 ± 18) mg/L]. The serum level of Ang-1 at 8 h and 24 h was one of independent risk factors for aSAH patients by multiariable Logistic regression analysis [adjected OR (95% CI) 1.095 (1.015-1.181) and 1.109 (1.016-1.211)] (P < 0.05). High serum level of Ang-1 during an early period (within 72 h) was associated with good outcomers (r = 0.627, P < 0.001). The serum levels of angiopoietins are significantly altered in aSAH patients, especially higher in good outcomers. And abnormal levels of angiopoietins may affect early brain injury (EBI) after SAH, structural integrity and recovery of blood-brain barrier (BBB) and long-term outcomes in aSAH patients.

Interceptive orthopedics for the correction of maxillary transverse and sagittal deficiency in the early mixed dentition period

PubMed Central

Talapaneni, Ashok Kumar; Kumar, Karnati Praveen; Kommi, Pradeep Babu; Nuvvula, Sivakumar

2011-01-01

Dentofacial Orthopedics directed to a hypoplastic maxilla in the prepubertal period redirects growth of the maxilla in the vertical, transverse and sagittal planes of space. The orthopedic correction of maxillary hypoplasia in the early mixed dentition period thus intercepts the establishment of permanent structural asymmetry in the mandible and helps in the achievement of optimal dentofacial esthetics. This paper presents the growth redirection in a hypoplastic maxilla of an 8-year-old girl with simultaneous rapid maxillary expansion and protraction headgear therapy for a period of 11 months which corrected the posterior unilateral cross-bite, the positional asymmetry of the mandible and established an orthognathic profile in the individual. PMID:22346162

Dolomitization in Late Jurassic-Early Cretaceous Platform Carbonates (Berdiga Formation), Ayralaksa Yayla (Trabzon), NE Turkey

NASA Astrophysics Data System (ADS)

Yıldız, Merve; Ziya Kırmacı, Mehmet; Kandemir, Raif

2017-04-01

ABSTRACT Pontides constitute an E-W trending orogenic mountain belt that extends about 1100 km along the northern side of Turkey from the immediate east of Istanbul to the Georgian border at the east. Tectono-stratigraphically, the Pontides are divided into three different parts: Eastern, Central, and Western Pontides. The Eastern Pontides, including the studied area, comprise an area of 500 km in length and 100 km in width, extending along the southeast coast of the Black Sea from the Kizilirmak and Yesilirmak Rivers in the vicinity of Samsun to the Little Caucasus. This area is bordered by the Eastern Black Sea basin to the north and the Ankara-Erzincan Neotethyan suture zone to the south. The Late Jurassic-Early Cretaceous platform carbonates are widely exposed in E-W direction in the Eastern Pontides (NE Turkey). The Platform carbonates shows varying lithofacies changing from supratidal to platform margin reef laterally and vertically, and was buried until the end of Late Cretaceous. The studied Ayralaksa Yayla (Trabzon, NE Turkey) area comprises one of the best typical exposures of formation in northern zone of Eastern Pontides. In this area, the lower parts of the formation are pervasively dolomitized by fabric-destructive and fabric-preserving replacement dolomite which are Ca-rich and nonstoichiometric (Ca56-66Mg34-44). Replacement dolomites (Rd) are represented by D18O values of -19.0 to -4.2 (VPDB), D13C values of 4.4 to 2.1 \\permil (VPDB) and 87Sr/86Sr ratios of 0.70889 to 0.70636. Petrographic and geochemical data indicate that Rd dolomites are formed prior to compaction at shallow-moderate burial depths from Late Jurassic-Early Cretaceous seawater and/or partly modified seawater as a result of water/rock interaction and they were recrystallized at elevated temperatures during subsequent burial. In the subsequent diagenetic process during the Late Cretaceous when the region became a magmatic arc, as a result of interaction with Early Jurassic volcanic

Evaluation of right ventricular function in early period following transcatheter closure of atrial septal defect.

PubMed

Ağaç, Mustafa Tarık; Akyüz, Ali Rıza; Acar, Zeydin; Akdemir, Ramazan; Korkmaz, Levent; Kırış, Abdülkadir; Erkuş, Emre; Erkan, Hakan; Celik, Sükrü

2012-03-01

There is limited data on alterations in novel right ventricular (RV) function indices like tricuspid annular plane systolic excursion (TAPSE) and tricuspid annular systolic velocity (TASV) after transcatheter atrial septal defect (ASD) closure. We aimed to evaluate RV function by echocardiography (ECG) with these novel indices in early period in patients with secundum-type ASD that was closed percutaneously. Patients were enrolled to study if they had secundum-type ASD that was suitable for percutaneous closure. Patient population consisted of 4 men and 16 women. Echocardiography was performed before and 1 month after closure. Mean age was 37 ± 16. Mean diameter of ASD and total atrial septum length measured by ECG were 19 ± 6 mm and 49 ± 7 mm, respectively. Mean diameter of defect in transesophageal echocardiography was 20 ± 6 mm. Stretched mean diameter in catheterization was 23 ± 6 mm. One month after closure, there were statistically significant decreases in RV end-diastolic diameters (43.3 ± 10.7 mm vs. 34.9 ± 5.5 mm; P < 0.001), RV/left ventricular (LV) end-diastolic diameter ratio (1.1 ± 0.3 vs. 0.87 ± 0.1; P < 0.001), TASV (16.9 ± 3.2 cm/sec vs. 14.3 ± 3.3 cm/sec; P < 0.05), early diastolic tricuspid annular velocity (15.3 ± 3.1 cm/sec vs. 13.4 ± 2.4 cm/sec P <0.05), late diastolic tricuspid annular velocity (16.2 ± 5.4 cm/sec vs. 14.3 ± 6.3 cm/sec; P < 0.05), and TAPSE (29.9 ± 6.2 mm vs. 22.4 ± 7.4 mm; P < 0.001). LV end-diastolic diameter (38.0 ± 6.9 mm and 40.0 ± 4.5 P < 0.05) was increased, whereas there was no change in LV ejection fraction. Closure of ASD by using Amplatzer devices led to decrease in right heart chamber size, tissue Doppler-derived tricuspid annular velocities and TAPSE in early period. © 2011, Wiley Periodicals, Inc.

Estimation of abbreviated mycophenolic acid area under the concentration-time curve during early posttransplant period by limited sampling strategy.

PubMed

Mohammadpour, A-H; Nazemian, F; Abtahi, B; Naghibi, M; Gholami, K; Rezaee, S; Nazari, M-R A; Rajabi, O

2008-12-01

Area under the concentration curve (AUC) of mycophenolic acid (MPA) could help to optimize therapeutic drug monitoring during the early post-renal transplant period. The aim of this study was to develop a limited sampling strategy to estimate an abbreviated MPA AUC within the first month after renal transplantation. In this study we selected 19 patients in the early posttransplant period with normal renal graft function (glomerular filtration rate > 70 mL/min). Plasma MPA concentrations were measured using reverse-phase high-performance liquid chromatography. MPA AUC(0-12h) was calculated using the linear trapezoidal rule. Multiple stepwise regression analysis was used to determine the minimal and convenient time points of MPA levels that could be used to derive model equations best fitted to MPA AUC(0-12h). The regression equation for AUC estimation that gave the best performance was AUC = 14.46 C(10) + 15.547 (r(2) = .882). The validation of the method was performed using the jackknife method. Mean prediction error of this model was not different from zero (P > .05) and had a high root mean square prediction error (8.06). In conclusion, this limited sampling strategy provided an effective approach for therapeutic drug monitoring during the early posttransplant period.

Mode of Birth Influences Preterm Infant Intestinal Colonization with Bacteroides Over the Early Neonatal Period

PubMed Central

Gregory, Katherine E.; LaPlante, Rose D.; Shan, Gururaj; Kumar, Deepak Vijaya; Gregas, Matt

2015-01-01

Background Intestinal colonization during infancy is important to short and long term health outcomes. Bacteroides, an early member of the intestinal microbiome, are necessary for breaking down complex molecules within the intestine and function to assist the body’s immune system in fighting against potentially harmful pathogens. Little is known about the colonization pattern of Bacteroides in preterm infants during the early neonatal period. Purpose This study measured Bacteroides colonization during the early neonatal period in a population of preterm infants based on clinical factors including mode of birth, antibiotics, and nutrition. Methods Bacterial DNA was isolated from 144 fecal samples from 29 preterm infants and analyzed using quantitative real time polymerase chain reaction (PCR). Analyses included liner mixed models to determine which clinical factors affect Bacteroides colonization of the infant gut. Results We found that infants born via vaginal canal had a higher rate of increase in Bacteroides than infants born via Cesarean section (p<.001). We did not find significant associations between antibiotic administration and differences in nutritional exposures with Bacteroides colonization. Implications for Practice These findings highlight the significant influence of mode of birth on Bacteroides colonization. While mode of birth is not always modifiable, these study findings may help develop interventions for preterm infants born via Cesarean section aimed at overcoming delayed Bacteroides colonization. Implications for Research Greater study of the intestinal microbiome and the clinical factors relevant to the preterm infant is needed so that interventions may be developed and tested, resulting in optimal microbial and immune health. PMID:26551793

Convective radiation fluid-dynamics: formation and early evolution of ultra low-mass objects

NASA Astrophysics Data System (ADS)

Wuchterl, G.

2005-12-01

The formation process of ultra low-mass objects is some kind of extension of the star formation process. The physical changes towards lower mass are discussed by investigating the collapse of cloud cores that are modelled as Bonnor-Ebert spheres. Their collapse is followed by solving the equations of fluid dynamics with radiation and a model of time-dependent convection that has been calibrated to the Sun. For a sequence of cloud-cores with 1 to 0.01 solar masses, evolutionary tracks and isochrones are shown in the mass-radius diagram, the Hertzsprung-Russel diagram and the effective temperature-surface gravity or Kiel diagram. The collapse and the early hydrostatic evolution to ages of few Ma are briefly discussed and compared to observations of objects in Upper Scorpius and the low-mass components of GG Tau.

Early stages of memory formation in filial imprinting: Fos-like immunoreactivity and behavior in the domestic chick.

PubMed

Suge, R; McCabe, B J

2004-01-01

Early stages of memory formation in filial imprinting were studied in domestic chicks. Chicks trained for 15 min showed strong imprinting, demonstrated by a strong preference for their training stimulus, and the time course of this preference over 2 days after training was similar to that of chicks trained for 60 min. The chicks therefore learned characteristics of the training stimulus very early during training. The intermediate and medial hyperstriatum ventrale (IMHV) is a part of the chick forebrain that is crucial for imprinting. Previous experiments have shown a learning-specific increase in Fos-like immunoreactivity, used as a marker of neuronal activity, in the IMHV after training for 60 min. The time course of Fos expression in the IMHV was measured after training for 15 min and 60 min. The same pattern of expression was found for both training times, showing a peak 120 min after the start of training. The time course of expression was stimulus-dependent. Fos expression in the IMHV, but not the hippocampus, was significantly correlated with strength of imprinting. It is concluded that the learning-specific change in Fos expression in the IMHV is associated with very early components of memory formation.

Abnormal early cleavage events predict early embryo demise: sperm oxidative stress and early abnormal cleavage.

PubMed

Burruel, Victoria; Klooster, Katie; Barker, Christopher M; Pera, Renee Reijo; Meyers, Stuart

2014-10-13

Human embryos resulting from abnormal early cleavage can result in aneuploidy and failure to develop normally to the blastocyst stage. The nature of paternal influence on early embryo development has not been directly demonstrated although many studies have suggested effects from spermatozoal chromatin packaging, DNA damage, centriolar and mitotic spindle integrity, and plasma membrane integrity. The goal of this study was to determine whether early developmental events were affected by oxidative damage to the fertilizing sperm. Survival analysis was used to compare patterns of blastocyst formation based on P2 duration. Kaplan-Meier survival curves demonstrate that relatively few embryos with short (<1 hr) P2 times reached blastocysts, and the two curves diverged beginning on day 4, with nearly all of the embryos with longer P2 times reaching blastocysts by day 6 (p < .01). We determined that duration of the 2nd to 3rd mitoses were sensitive periods in the presence of spermatozoal oxidative stress. Embryos that displayed either too long or too short cytokineses demonstrated an increased failure to reach blastocyst stage and therefore survive for further development. Although paternal-derived gene expression occurs later in development, this study suggests a specific role in early mitosis that is highly influenced by paternal factors.

Pacopampa: Early evidence of violence at a ceremonial site in the northern Peruvian highlands.

PubMed

Nagaoka, Tomohito; Uzawa, Kazuhiro; Seki, Yuji; Morales Chocano, Daniel

2017-01-01

Pacopampa, a ceremonial complex in Peru's northern highlands, reveals early evidence of trauma in the Middle to Late Formative Period coinciding with the emergence of social stratification in the area. We examine the prevalence of trauma in human remains found at the site and present evidence of the circumstances surrounding the deaths of individuals who lived during the early stages of Andean civilization. The materials are the remains of 104 individuals (38 non-adult and 66 adult) from the Middle to Late Formative Periods. We explored trauma macroscopically and recorded patterns based on skeletons' locations, age at death, sex, social class, and chronology. We detected trauma in remains over the Middle to Late Formative Periods. While the prevalence of trauma was minimal in the Middle Formative Period, skeletons from the subsequent era exhibit more severe disturbances. However, all the skeletons show signs of healing and affected individuals experienced a low degree of trauma. Given the archaeological context (the remains were recovered from sites of ceremonial practices), as well as the equal distribution of trauma among both sexes and a lack of defensive architecture, it is plausible that rituals, rather than organized warfare or raids, caused most of the exhibited trauma. Pacopampa was home to a complex society founded on ritual activity in a ceremonial center: this is indicated by the presence of ritual violence in a society that built impressively large, ceremonial architecture and developed social stratification without any political control of surplus agricultural goods.

Geologically Controlled Isotope-Time Patterns Reveal Early Differentiation and Crust Formation Processes

NASA Astrophysics Data System (ADS)

Bennett, V. C.; Nutman, A. P.

2014-12-01

The mechanisms of continental crust production and evolution in the early Earth remain controversial, as are questions of the relative roles of early differentiation versus subsequent tectonic procssing in creating Earth's chemical signatures. Here we present geologic observations integrated with whole rock major, trace element and Sm-Nd isotopic signatures and combined with U-Pb and Lu-Hf isotopic compositions of zircon populations from the same rocks, from the most extensive early rock record comprising the 3.9 Ga to 3.6 Ga terranes of southwest Greenland. These data reveal repeated patterns of formation of juvenile TTG crust and associated mafic and ultramafic rocks in convergent margin settings followed by formation of more evolved granites [1]. Our new zircon Lu-Hf data from rare 3.6-3.7 Ga tonalites within the Itsaq Gneiss Complex, obtained from single component, non-migmatitic gneisses with simple zircon populations, limited within sample Hf isotopic variability and accurate U-Pb ages, now document extraction of juvenile tonalites from a near chondritic mantle source between 3.9 Ga and 3.6 Ga. The more evolved, granitic rocks in each area show slightly negative initial ɛHf in accord with crustal reworking of the older (3.8-3.9 Ga) gniesses. There is no evidence for Hadean material in the sources of the granitoids. The Hf isotope-time patterns are consistent with juvenile crust production from a mantle source that experienced only modest amounts of prior crustal extraction. They are distinct from those predicted by reprocessing of an enriched Hadean mafic crust, as has been proposed for this region [2] and for the source of the Hadean Jack Hills zircons [3]. The well-documented, time decreasing, positive 142Nd anomalies [e.g., 4] from these rocks are further evidence of crustal derivation from a convecting mantle source, rather than reworking of an enriched mafic lithosphere. The 143Nd isotopic -time patterns are more complex, reflecting the interplay

Early Mars: The inextricable link between internal and external influences on valley network formation

NASA Technical Reports Server (NTRS)

Postawko, S. E.; Fanale, F. P.

1993-01-01

The conditions under which the valley networks on the ancient cratered terrain on Mars formed are still highly debated within the scientific community. While liquid water was almost certainly involved, the exact mechanism of formation is uncertain. The networks most resemble terrestrial sapping channels, although some systems exhibit a runoff-dominated morphology. The major question in the formation of these networks is what, if anything, do they imply about early Martian climate? There are typically two major theories advanced to explain the presence of these networks. The first is that higher internal regolith temperatures, associated with a much higher heat flow 3.8 b.y. ago, would cause ground water to be closer to the surface than at present. Just how close to the surface ground water would have to exist in order to form these valley networks has recently been questioned. The second major theory is that early Mars had a much thicker atmosphere than at present, and an enhanced atmospheric greenhouse may have increased surface temperatures to near the freezing point of water. While recent calculations indicate that CO2 alone could not have produced the needed warming, the presence of other greenhouse gases may have contributed to surface warming.

Early extubation after cardiac surgery: emotional status in the early postoperative period.

PubMed

Silbert, B S; Santamaria, J D; Kelly, W J; O'brien, J L; Blyth, C M; Wong, M Y; Allen, N B

2001-08-01

To compare the emotional state during the first 3 days after coronary artery surgery of patients who had undergone early versus conventional extubation. A prospective, randomized, controlled trial. University hospital, single center. Eligible patients (n = 100) presenting for elective coronary artery surgery, randomized to an early extubation group or a conventional extubation group. Emotional status was measured by the Hospital Anxiety and Depression Scale (HAD), the Self Assessment Manikin (SAM), and the Multiple Affect Adjective Check List-Revised (MAACL-R). Tests were administered preoperatively and on the 1st and 3rd days postoperatively. Of patients in the conventional extubation group, 30% showed moderate-to-severe depressive symptoms (HAD score >10) on day 3 postoperatively compared with 8% of patients in the early extubation group (p = 0.02). There was a clinically insignificant increase in MAACL-R depression score on the 1st postoperative day within both groups but no other differences within or between groups in SAM or MAACL-R scores. Early extubation results in fewer patients displaying depressive symptoms on the 3rd postoperative day but appears to have little effect on other measurements of emotional status. Anesthetic management during coronary artery bypass graft surgery may play an important role in the overall well-being of the patient by decreasing the incidence of postoperative depression. Copyright 2001 by W.B. Saunders Company.

Early Stage of Origin of Earth (interval after Emergence of Sun, Formation of Liquid Core, Formation of Solid Core)

NASA Astrophysics Data System (ADS)

Pechernikova, G. V.; Sergeev, V. N.

2017-05-01

Gravitational collapse of interstellar molecular cloud fragment has led to the formation of the Sun and its surrounding protoplanetary disk, consisting of 5 × 10^5 dust and gas. The collapse continued (1 years. Age of solar system (about 4.57×10^9 years) determine by age calcium-aluminum inclusions (CAI) which are present at samples of some meteorites (chondrites). Subsidence of dust to the central plane of a protoplanetary disk has led to formation of a dust subdisk which as a result of gravitational instability has broken up to condensations. In the process of collisional evolution they turned into dense planetesimals from which the planets formed. The accounting of a role of large bodies in evolution of a protoplanetary swarm in the field of terrestrial planets has allowed to define times of formation of the massive bodies permitting their early differentiation at the expense of short-lived isotopes heating and impacts to the melting temperature of the depths. The total time of Earth's growth is estimated about 10^8 years. Hf geochronometer showed that the core of the Earth has existed for Using W about 3×10^7 Hf geohronometer years since the formation of the CAI. Thus data W point to the formation of the Earth's core during its accretion. The paleomagnetic data indicate the existence of Earth's magnetic field past 3.5×10^9 years. But the age of the solid core, estimated by heat flow at the core-mantle boundary is 1.7×10^9 (0.5 years). Measurements of the thermal conductivity of liquid iron under the conditions that exist in the Earth's core, indicate the absence of the need for a solid core of existence to support the work geodynamo, although electrical resistivity measurements yield the opposite result.

A critical period for gravitational effects on otolith formation

NASA Astrophysics Data System (ADS)

Wiederhold, M.; Harrison, J.

Gravity and linear acceleration are sensed in fish by the saccule, utricle (as in mammals) and lagena, each with a solid otolith. Previous experiments in which eggs or larvae of a marine mollusk ( plysia) or fish larvae were raised on aA centrifuge, demonstrated that the size of the otolith or statoconia (in Aplysia) were reduced, in a graded manner, as the gfield was increased, suggesting that some- control mechanism was acting to normalize the weight of the mass. Pre-mated adult female swordtail fish (Xiphophorus helleri) were flown in the CEBAS aquarium system on space shuttle missions STS 89 and STS-90 (Neurolab). Developing- larvae were removed from the adult ovaries after shuttle landing. Otolith sizes were compared between ground- and flight -reared larvae of similar sizes. For later-stage swordtail larvae, with spine lengths from 3 to 6 mm from STS-90 (16 days), the growth of the otolith with increasing spine length was significantly greater in the flight - reared fish for all three otoliths, from the saccule (saggita), utricle (lapillus) and lagena (astericus). However, juvenile fish, 1 cm long at launch, showed no significant difference in otolith size between flight - and ground-reared animals. In very early stage larvae from STS-89 (9 days), with spine length of 1.5 to 3.5 mm, the utricular and saccular otoliths were actually larger in the ground-reared larvae. Thus, it appears that late-stage fish embryos reared in space do produce larger-than - normal otoliths, apparently in an attempt to c mpensate for the reduced weight ofo the test mass in space. However, the results from very early-stage larvae and juvenile fish suggest that there is a fairly short critical period during which altered gravity can affect the size of the test mass. Recent studies on the development of the inner ear of the zebrafish (Danio raria) may explain the critical period for gravitational effects on otolith growth. By 16 hours after zebrafish fertilization (at 28.5 o

A collisional model for the formation of ripples in early-type disk galaxies

NASA Technical Reports Server (NTRS)

Wallin, John F.; Struck-Marcell, Curtis

1988-01-01

Restricted three-body calculations of high-inclination low-impact-parameter encounters between a disk galaxy and its companion are used to demonstrate that the shell-like ripples noted in a number of disk galaxies are also collisional artifacts. It is suggested that some of the ripples may be the results of internal oscillations following such encounters. It is assumed that the target is an early-type disk with a sufficiently low gas fraction that recent star formation does not dominate the appearance of the disturbed disk.

Early to Middle Jurassic tectonic evolution of the Bogda Mountains, Northwest China: Evidence from sedimentology and detrital zircon geochronology

NASA Astrophysics Data System (ADS)

Ji, Hongjie; Tao, Huifei; Wang, Qi; Qiu, Zhen; Ma, Dongxu; Qiu, Junli; Liao, Peng

2018-03-01

The Bogda Mountains, as an important intracontinental orogenic belt, are situated in the southern part of the Central Asian Orogenic Belt (CAOB), and are a key area for understanding the Mesozoic evolution of the CAOB. However, the tectonic evolution of the Bogda Mountains remains controversial during the Mesozoic Era, especially the Early to Middle Jurassic Periods. The successive Lower to Middle Jurassic strata are well preserved and exposed along the northern flank of the Western Bogda Mountains and record the uplift processes of the Bogda Mountains. In this study, we analysed sedimentary facies combined with detrital zircon U-Pb geochronology at five sections of Lower to Middle Jurassic strata to detect the tectonic evolution and changes of provenance in the Bogda area. During Early to Middle Jurassic times, the fluvial, deltaic and lacustrine environments dominated in the western section of the Bogda area. The existence of Early Triassic peak age indicates that the Bogda Mountains did not experience uplift during the period of early Badaowan Formation deposition. The Early Triassic to Late Permian granitoid plutons and Carboniferous volcanic rocks from the Barkol and Santanghu areas were the main provenances. The significant change in the U-Pb age spectrum implies that the Eastern Bogda Mountains initiated uplift in the period of late Badaowan Formation deposition, and the Eastern Junggar Basin and the Turpan-Hami Basin were partially partitioned. The Eastern Bogda Mountains gradually became the major provenance. From the period of early Sangonghe to early Toutunhe Formations deposition, the provenance of the sediments and basin-range frame were similar to that of late Badaowan. However, the Eastern Bogda Mountains suffered intermittent uplift three times, and successive denudation. The uplifts respectively happened in early Sangonghe, late Sangonghe to early Xishanyao, and late Xishanyao to early Toutunhe. During the deposition stage of Toutunhe Formation, a

A Guide to Screening for the Early and Periodic Screening, Diagnosis and Treatment Program (EPSDT) Under Medicaid.

ERIC Educational Resources Information Center

Frankenburg, William K.; North, A. Frederick, Jr.

The manual was designed to help public officials, physicians, nurses, and others to plan and implement an Early and Periodic Screening, Diagnosis and Treatment (EPSDT) program under Medicaid. Procedures for carrying out components of an EPSDT program are recommended. Part 1 discusses organization and administration of screening, diagnosis, and…

Prevalence of pannus formation after aortic valve replacement: clinical aspects and surgical management.

PubMed

Sakamoto, Yoshimasa; Hashimoto, Kazuhiro; Okuyama, Hiroshi; Ishii, Shinichi; Shingo, Taguchi; Kagawa, Hiroshi

2006-01-01

Pannus formation after aortic valve replacement is not common, but obstruction due to chronic pannus is one of the most serious complications of valve replacement. The causes of pannus formation are still unknown and effective preventive methods have not been fully elucidated. We reviewed our clinical experience of all patients who underwent reoperation for prosthetic aortic valve obstruction due to pannus formation between 1973 and 2004. We compared the initial 18-year period of surgery, when the Björk-Shiley tilting-disk valve was used, and the subsequent 13-year period of surgery, when the St. Jude Medical valve was used. Seven of a total of 390 patients (1.8%) required reoperation for prosthetic aortic valve obstruction due to pannus formation. All seven patients were women; four patients underwent resection of the pannus and three patients needed replacement of the valve. The frequency of pannus formation in the early group was 2.4% (6/253), whereas it was 0.73% (1/137) in the late group (P < 0.05). Pannus was localized at the minor orifice of the Björk-Shiley valve in the early group and turbulent transvalvular blood flow was considered to be one of the important factors triggering its growth. We also consider that small bileaflet valves have the possibility of promoting pannus formation and that the implantation of a larger prosthesis can contribute to reducing the occurrence of pannus.

Installation of a Rudist Biostrome after the Late Aptian - Early Albian OAE1B (mural Formation, Southeastern Arizona)

NASA Astrophysics Data System (ADS)

Godet, A.; Helfrich-Dennis, M. M.; Suarez, M. B.

2015-12-01

Mesozoic climate change has been extensively studied in the Tethys, while their expression in the proto Gulf of Mexico can still be precised, especially for the time period straddling the Aptian-Albian boundary. During this time period, significant climatic events may correlate between the proto-Atlantic and the Tethys, amongst which the Oceanic Anoxic Event 1b that corresponds to a period of marine anoxia across this stage boundary. We hypothesized that this event may have impacted the shallow-marine carbonate factory that is now preserved near the town of Bisbee (Mule Mountains, southern Arizona). This sedimentary succession has been chosen because it documents a switch from a siliclastic- to carbonate-dominated sedimentation during the targeted time interval. Using carbon isotope chemostratigraphy, we were able to refine the stratigraphic framework of the Mural Formation, which was previously based on benthic organisms such as rudist bivalves and orbitolinids, such as Mesorbitolina texana. The OAE1b has been identified based on its peculiar δ13C signature supported by biostratigraphic data. Concurrently, microfacies analysis helped in reconstructing variations in sea levels. In southern Arizona, the OAE1b equivalent belongs to a third-order transgressive systems tract, and extends into the following highstand systems track. The maximum flooding surface is defined within a thick rudist biostrome with chondrodonts. It thus seems that the OAE1b did not strongly affected the carbonate factory in this region of the proto Gulf of Mexico. As a conclusion, limestone rocks now preserved in southeastern Arizona were deposited during the Late Aptian to Early Albian time period, during which the OAE1b developed. This paleoceanographic perturbation is expressed in the sedimentary record by its unique carbon isotope signature, with no significant impact on benthic ecosystems.

Early action to reduce greenhouse gas emissions before the commitment period of the Kyoto protocol: advantages and disadvantages.

PubMed

Michaelowa, A; Rolfe, C

2001-09-01

Current "business as usual" projections suggest greenhouse gas emissions from industrialized nations will grow substantially over the next decade. However, if it comes into force, the Kyoto Protocol will require industrialized nations to reduce emissions to an average of 5% below 1990 levels in the 2008-2012 period. Taking early action to close this gap has a number of advantages. It reduces the risks of passing thresholds that trigger climate change "surprises." Early action also increases future generations' ability to choose greater levels of climate protection, and it leads to faster reductions of other pollutants. From an economic sense, early action is important because it allows shifts to less carbon-intensive technologies during the course of normal capital stock turnover. Moreover, many options for emission reduction have negative costs, and thus are economically worthwhile, because of paybacks in energy costs, healthcare costs, and other benefits. Finally, early emission reductions enhance the probability of successful ratification and lower the risk of noncompliance with the protocol. We discuss policy approaches for the period prior to 2008. Disadvantages of the current proposals for Credit for Early Action are the possibility of adverse selection due to problematic baseline calculation methods as well as the distributionary impacts of allocating a part of the emissions budget already before 2008. One simple policy without drawbacks is the so-called baseline protection, which removes the disincentive to early action due to the expectation that businesses may, in the future, receive emission rights in proportion to past emissions. It is particularly important to adopt policies that shift investment in long-lived capital stock towards less carbon-intensive technologies and to encourage innovation and technology development that will reduce future compliance costs.

Nucleobase and amino acid formation through impacts of meteorites on the early ocean

NASA Astrophysics Data System (ADS)

Furukawa, Yoshihiro; Nakazawa, Hiromoto; Sekine, Toshimori; Kobayashi, Takamichi; Kakegawa, Takeshi

2015-11-01

The emergence of life's building blocks on the prebiotic Earth was the first crucial step for the origins of life. Extraterrestrial delivery of intact amino acids and nucleobases is the prevailing hypothesis for their availability on prebiotic Earth because of the difficulties associated with the production of these organics from terrestrial carbon and nitrogen sources under plausible prebiotic conditions. However, the variety and amounts of these intact organics delivered by meteorites would have been limited. Previous shock-recovery experiments have demonstrated that meteorite impact reactions could have generated organics on the prebiotic Earth. Here, we report on the simultaneous formation of nucleobases (cytosine and uracil) found in DNA and/or RNA, various proteinogenic amino acids (glycine, alanine, serine, aspartic acid, glutamic acid, valine, leucine, isoleucine, and proline), non-proteinogenic amino acids, and aliphatic amines in experiments simulating reactions induced by extraterrestrial objects impacting on the early oceans. To the best of our knowledge, this is the first report of the formation of nucleobases from inorganic materials by shock conditions. In these experiments, bicarbonate was used as the carbon source. Bicarbonate, which is a common dissolved carbon species in CO2-rich atmospheric conditions, was presumably the most abundant carbon species in the early oceans and in post-impact plumes. Thus, the present results expand the possibility that impact-induced reactions generated various building blocks for life on prebiotic Earth in large quantities through the use of terrestrial carbon reservoirs.

The conchostracan subgenus Orthestheria (Migransia) from the Tacuarembó Formation (Late Jurassic-?Early Cretaceous, Uruguay) with notes on its geological age

NASA Astrophysics Data System (ADS)

Yanbin, Shen; Gallego, Oscar F.; Martínez, Sergio

2004-04-01

Conchostracans from the Tacuarembó Formation s.s. of Uruguay are reassigned to the subgenus Orthestheria (Migransia) Chen and Shen. They show more similarities to genera of Late Jurassic age in the Congo Basin and China than to those of Early Cretaceous age. On the basis of the character of the conchostracans, we suggest that the Tacuarembó Formation is unlikely to be older than Late Jurassic. It is probably Kimmeridgian, but an Early Cretaceous age cannot be excluded. This finding is consistent with isotopic dating of the overlying basalts, as well as the age range of recently described fossil freshwater sharks.

The Origin of Dust in the Early Universe: Probing the Star Formation History of Galaxies by Their Dust Content

NASA Technical Reports Server (NTRS)

Dwek, Eli; Cherchneff, Isabelle

2010-01-01

Two distinct scenarios for the origin of the approximately 4 x 10(exp 8) Solar Mass of dust observed in the high-redshift (z = 6.4) quasar J1148+5251 have been proposed. The first assumes that this galaxy is much younger than the age of the universe at that epoch so that only supernovae, could have produced this dust. The second scenario assumes a significantly older galactic age, so that the dust could have formed in lower-mass AGB stars. Presenting new integral solutions for the chemical evolution of metals and dust in galaxies, we offer a critical evaluation of these two scenarios. ^N;"(,, show that the AGB scenario is sensitive to the details of the galaxy's star formation history (SFH), which must consist of an early intense starburst followed by a period of low stellar activity. The presence or absence of massive amounts of dust in high-redshift galaxies can therefore be used to infer their SFH. However, a problem with the AGB scenario is that it produces a stellar mass that is significantly larger than the inferred dynamical mass of J1148+5251, an yet unresolved discrepancy. If this problem persists, then additional sites for the growth or formation of dust, such as molecular clouds or dense clouds around active galactic nuclei, must be considered.

Effects of dry period length and dietary energy source on metabolic status and hepatic gene expression of dairy cows in early lactation.

PubMed

Chen, J; Gross, J J; van Dorland, H A; Remmelink, G J; Bruckmaier, R M; Kemp, B; van Knegsel, A T M

2015-02-01

In a prior study, we observed that cows with a 0-d dry period had greater energy balance and lower milk production compared with cows with a 30- or 60-d dry period in early lactation. The objective of the current study was to evaluate the influence of dry period length on metabolic status and hepatic gene expression in cows fed a lipogenic or glucogenic diet in early lactation. Holstein-Friesian dairy cows (n=167) were assigned randomly to 3×2 factorial design with 3 dry period lengths (n=56, 55, and 56 for 0-, 30-, and 60-d dry, respectively) and 2 early lactation diets (n=84 and 83 for glucogenic and lipogenic diet, respectively). Cows were fed a glucogenic or lipogenic diet from 10d before the expected calving date and onward. The main ingredient for a glucogenic concentrate was corn, and the main ingredients for a lipogenic concentrate were sugar beet pulp, palm kernel, and rumen-protected palm oil. Blood was sampled weekly from 95 cows from wk 3 precalving to wk 8 postcalving. Liver samples were collected from 76 cows in wk -2, 2, and 4 relative to calving. Liver samples were analyzed for triacylglycerol concentrations and mRNA expression of 12 candidate genes. Precalving, cows with a 0-d dry period had greater plasma β-hydroxybutyrate, urea, and insulin concentrations compared with cows with a 30- or 60-d dry period. Postcalving, cows with a 0-d dry period had lower liver triacylglycerol and plasma nonesterified fatty acids concentrations (0.20, 0.32, and 0.36mmol/L for 0-, 30-, and 60-d dry period, respectively), greater plasma glucose, insulin-like growth factor-I, and insulin (24.38, 14.02, and 11.08µIU/mL for 0-, 30-, and 60-d dry period, respectively) concentrations, and lower hepatic mRNA expression of pyruvate carboxylase, compared with cows with a 30- or 60-d dry period. Plasma urea and β-hydroxybutyrate concentrations were greater in cows fed a lipogenic diet compared with cows fed a glucogenic diet. In conclusion, cows with a 0-d dry period had

Treponemal disease in the middle Archaic to early Woodland periods of the western Tennessee River Valley.

PubMed

Smith, Maria Ostendorf

2006-10-01

The high frequency of late prehistoric New World treponemal disease is attributable to the demographic changes concomitant with the adoption of agriculture. However, these demographic changes in group mobility and site density episodically preceded intensive plant domestication, suggesting possible staggered temporal change in observed treponemal disease case frequency. Thirteen convincing and an additional two probable (N = 581) cases of treponemal disease were identified in an eight-site skeletal sample spanning the Middle (6,000-3,000 BCE) to Late (2,500-ca. 1,000 to 500 BCE) Archaic and Early Woodland (500 BCE-0 CE) periods from the western Tennessee River Valley. Treponemal disease cases are infrequent in both the Middle (3/115, 2.6%) and Late (2 to 4 cases, Early Woodland horizon. As the subsistence economy across the Archaic-Woodland temporal boundary in the western Tennessee River Valley remained, as elsewhere, based on intensive hunting and collecting, the demographic corollaries of treponemal disease would apparently not be met. However, the traditional horizon marker of the Woodland period is the adoption of pottery, an activity associated with sedentism.

Myocardial Tbx20 regulates early atrioventricular canal formation and endocardial epithelial-mesenchymal transition via Bmp2

PubMed Central

Cai, Xiaoqiang; Nomura-Kitabayashi, Aya; Cai, Weibin; Yan, Jianyun; Christoffels, Vincent M.; Cai, Chen-Leng

2011-01-01

During early embryogenesis, the formation of the cardiac atrioventricular canal (AVC) facilitates the transition of the heart from a linear tube into a chambered organ. However, the genetic pathways underlying this developmental process are poorly understood. The T-box transcription factor Tbx20 is expressed predominantly in the AVC of early heart tube. It was shown that Tbx20 activates Nmyc1 and suppresses Tbx2 expression to promote proliferation and specification of the atrial and ventricular chambers, yet it is not known if Tbx20 is involved in early AVC development. Here, we report that mice lacking Tbx20 in the AVC myocardium fail to form the AVC constriction, and the endocardial epithelial-mesenchymal transition (EMT) is severely perturbed. Tbx20 maintains expression of a variety of genes, including Bmp2, Tbx3 and Hand1 in the AVC myocardium. Intriguingly, we found Bmp2 downstream genes involved in the EMT initiation are also downregulated. In addition, re-expression of Bmp2 in the AVC myocardium substantially rescues the EMT defects resulting from the lack of Tbx20, suggesting Bmp2 is one of the key downstream targets of Tbx20 in AVC development. Our data support a complex signaling network with Tbx20 suppressing Tbx2 in the AVC myocardium but also indirectly promoting Tbx2 expression through Bmp2. The spatiotemporal expression of Tbx2 in the AVC appears to be balanced between these two opposing signals. Overall, our study provides genetic evidence that Tbx20 has essential roles in regulating AVC development that coordinate early cardiac chamber formation. PMID:21983003

Myocardial Tbx20 regulates early atrioventricular canal formation and endocardial epithelial-mesenchymal transition via Bmp2.

PubMed

Cai, Xiaoqiang; Nomura-Kitabayashi, Aya; Cai, Weibin; Yan, Jianyun; Christoffels, Vincent M; Cai, Chen-Leng

2011-12-15

During early embryogenesis, the formation of the cardiac atrioventricular canal (AVC) facilitates the transition of the heart from a linear tube into a chambered organ. However, the genetic pathways underlying this developmental process are poorly understood. The T-box transcription factor Tbx20 is expressed predominantly in the AVC of early heart tube. It was shown that Tbx20 activates Nmyc1 and suppresses Tbx2 expression to promote proliferation and specification of the atrial and ventricular chambers, yet it is not known if Tbx20 is involved in early AVC development. Here, we report that mice lacking Tbx20 in the AVC myocardium fail to form the AVC constriction, and the endocardial epithelial-mesenchymal transition (EMT) is severely perturbed. Tbx20 maintains expression of a variety of genes, including Bmp2, Tbx3 and Hand1 in the AVC myocardium. Intriguingly, we found Bmp2 downstream genes involved in the EMT initiation are also downregulated. In addition, re-expression of Bmp2 in the AVC myocardium substantially rescues the EMT defects resulting from the lack of Tbx20, suggesting Bmp2 is one of the key downstream targets of Tbx20 in AVC development. Our data support a complex signaling network with Tbx20 suppressing Tbx2 in the AVC myocardium but also indirectly promoting Tbx2 expression through Bmp2. The spatiotemporal expression of Tbx2 in the AVC appears to be balanced between these two opposing signals. Overall, our study provides genetic evidence that Tbx20 has essential roles in regulating AVC development that coordinate early cardiac chamber formation. Copyright © 2011 Elsevier Inc. All rights reserved.

Ignition and early soot formation in a DI diesel engine using multiple 2-D imaging diagnostics

NASA Astrophysics Data System (ADS)

Dec, John E.; Espey, Christoph

Combined optical imaging diagnostics in the fuel jet of a direct-injection diesel engine to study the ignition and early soot formation processes. A diesel engine of the 'heavy-duty' size class was operated at a representative medium speed (1200 rpm) operating condition. Two fuels were used, a 42.5 cetane number mixture of the diesel reference fuels and a new low-sooting fuel. Combustion and soot formation are almost identical for both fuels. Ignition and early combustion were studied by imaging the natural chemiluminescence using a calibrated intensified video camera. Early soot development was investigated via luminosity imaging and simultaneous planar imaging of laser-induced incandescence (LII) and elastic scattering. The latter provide relative soot concentrations and particle size distributions. Data show that ignition occurs at multiple points across the downstream region of all the fuel jets prior to first apparent heat release well before any soot luminosity occurs. Quantitative vapor-fuel/air mixture images in the leading portion of the jet are also presented and discussed with respect to the early combustion data. The first soot occurs at random locations, and shortly thereafter, small soot particles develop throughout the cross section of the leading portion of the jet. Data indicate that this soot arises from the fuel-rich premixed burn. Then, significantly larger soot particles appear around the periphery of the jet, presumably from the initial diffusion combustion. By the end of the premixed burn, the soot has developed a distribution pattern of a higher concentration toward the front of the jet and a lower concentration upstream, with the larger-sized soot particles being generally confined to the periphery of the jet.

The Formation of Haze During the Rise of Oxygen in the Atmosphere of the Early Earth

NASA Astrophysics Data System (ADS)

Horst, S. M.; Jellinek, M.; Pierrehumbert, R.; Tolbert, M. A.

2014-12-01

also provide a wealth of organic material to the surface. Photochemical hazes are abundant in reducing atmospheres, such as the N2/CH4 atmosphere of Titan, but are unlikely to form in oxidizing atmospheres, such as the N2/O2 atmosphere of present day Earth. However, information about haze formation in mildly oxidizing atmospheres is lacking. Understanding haze formation in mildly oxidizing atmospheres is necessary for models that wish to investigate the atmosphere of the Early Earth as O2 first appeared and then increased in abundance. Previous studies of the atmosphere of the Early Earth have focused on haze formation in N2/CO2/CH4 atmospheres. In this work, we experimentally investigate the effect of the addition of O2 on the formation and composition of aerosols. Using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) (see e.g. [1]) we have obtained in situ composition measurements of aerosol particles produced in N2/CO2/CH4/O2 gas mixtures subjected to FUV radiation (deuterium lamp, 115-400 nm) for a range of initial CO2/CH4/O2 mixing ratios. In particular, we studied the effect of O2 ranging from 2 ppm to 2%. The particles were also investigated using a Scanning Mobility Particle Sizer (SMPS), which measures particle size, number density and mass loading. A comparison of the composition of the aerosols will be presented. The effect of variation of O2 mixing ratio on aerosol production, size, and composition will also be discussed. [1] Trainer, M.G., et al. (2012) Astrobiology, 12, 315-326.

Pacopampa: Early evidence of violence at a ceremonial site in the northern Peruvian highlands

PubMed Central

Uzawa, Kazuhiro; Seki, Yuji; Morales Chocano, Daniel

2017-01-01

Objectives Pacopampa, a ceremonial complex in Peru’s northern highlands, reveals early evidence of trauma in the Middle to Late Formative Period coinciding with the emergence of social stratification in the area. We examine the prevalence of trauma in human remains found at the site and present evidence of the circumstances surrounding the deaths of individuals who lived during the early stages of Andean civilization. Materials and methods The materials are the remains of 104 individuals (38 non-adult and 66 adult) from the Middle to Late Formative Periods. We explored trauma macroscopically and recorded patterns based on skeletons’ locations, age at death, sex, social class, and chronology. Results We detected trauma in remains over the Middle to Late Formative Periods. While the prevalence of trauma was minimal in the Middle Formative Period, skeletons from the subsequent era exhibit more severe disturbances. However, all the skeletons show signs of healing and affected individuals experienced a low degree of trauma. Discussion Given the archaeological context (the remains were recovered from sites of ceremonial practices), as well as the equal distribution of trauma among both sexes and a lack of defensive architecture, it is plausible that rituals, rather than organized warfare or raids, caused most of the exhibited trauma. Pacopampa was home to a complex society founded on ritual activity in a ceremonial center: this is indicated by the presence of ritual violence in a society that built impressively large, ceremonial architecture and developed social stratification without any political control of surplus agricultural goods. PMID:28957380

Simulation of the early startup period of high-temperature heat pipes from the frozen state by a rarefied vapor self-diffusion model

NASA Technical Reports Server (NTRS)

Cao, Y.; Faghri, A.

1993-01-01

The heat pipe startup process is described physically and is divided into five periods for convenience of analysis. The literature survey revealed that none of the previous attempts to simulate the heat pipe startup process numerically were successful, since the rarefied vapor flow in the heat pipe was not considered. Therefore, a rarefied vapor self-diffusion model is proposed, and the early startup periods, in which the rarefied vapor flow is dominant within the heat pipe, are first simulated numerically. The numerical results show that large vapor density gradients existed along the heat pipe length, and the vapor flow reaches supersonic velocities when the density is extremely low. The numerical results are compared with the experimental data of the early startup period with good agreement.

Lag periods during the self-assembly of {Mo(72)Fe(30)} macroions: connection to the virus capsid formation process.

PubMed

Zhang, Jie; Li, Dong; Liu, Guang; Glover, Kerney Jebrell; Liu, Tianbo

2009-10-28

The kinetic properties of the self-assembly of hydrophilic Keplerate-type polyoxometalate (POM) {Mo(72)Fe(30)} macroanions into single-layer, vesicle-like blackberry structures in solutions were monitored by the static and dynamic laser light scattering techniques. In the presence of additional electrolytes, an obvious lag period at the initial stage of self-assembly was observed, followed by a fast increase of the scattered intensity. The whole kinetic curve is sigmoidal with a lag phase. A two-step nucleation-growth mechanism is proposed to explain this lag phase: the {Mo(72)Fe(30)} macroanions slowly associate into oligomers (mostly dimers), which are the thermodynamically unfavorable intermediates, at the initial stage; once the oligomers reach a critical concentration, the blackberry formation process is accelerated. Analytical ultracentrifugation (AUC) was used to confirm the oligomeric state in {Mo(72)Fe(30)} solution during the lag period. The length of the lag period is dependent on temperature, ionic strength, and the valent states of the additional salts, as well as the solvent content. The kinetics (including the lag period) of the blackberry formation of the {Mo(72)Fe(30)} macroanions show similarities to the self-assembly of virus capsid proteins (which are also soluble macroions) into spherical capsid shells, suggesting possible connections between the self-assembly behaviors of inorganic species and biological macromolecules.

Prediction of rhythmic and periodic EEG patterns and seizures on continuous EEG with early epileptiform discharges.

PubMed

Koren, J; Herta, J; Draschtak, S; Pötzl, G; Pirker, S; Fürbass, F; Hartmann, M; Kluge, T; Baumgartner, C

2015-08-01

Continuous EEG (cEEG) is necessary to document nonconvulsive seizures (NCS), nonconvulsive status epilepticus (NCSE), as well as rhythmic and periodic EEG patterns of 'ictal-interictal uncertainty' (RPPIIU) including periodic discharges, rhythmic delta activity, and spike-and-wave complexes in neurological intensive care patients. However, cEEG is associated with significant recording and analysis efforts. Therefore, predictors from short-term routine EEG with a reasonably high yield are urgently needed in order to select patients for evaluation with cEEG. The aim of this study was to assess the prognostic significance of early epileptiform discharges (i.e., within the first 30 min of EEG recording) on the following: (1) incidence of ictal EEG patterns and RPPIIU on subsequent cEEG, (2) occurrence of acute convulsive seizures during the ICU stay, and (3) functional outcome after 6 months of follow-up. We conducted a separate analysis of the first 30 min and the remaining segments of prospective cEEG recordings according to the ACNS Standardized Critical Care EEG Terminology as well as NCS criteria and review of clinical data of 32 neurological critical care patients. In 17 patients with epileptiform discharges within the first 30 min of EEG (group 1), electrographic seizures were observed in 23.5% (n = 4), rhythmic or periodic EEG patterns of 'ictal-interictal uncertainty' in 64.7% (n = 11), and neither electrographic seizures nor RPPIIU in 11.8% (n = 2). In 15 patients with no epileptiform discharges in the first 30 min of EEG (group 2), no electrographic seizures were recorded on subsequent cEEG, RPPIIU were seen in 26.7% (n = 4), and neither electrographic seizures nor RPPIIU in 73.3% (n = 11). The incidence of EEG patterns on cEEG was significantly different between the two groups (p = 0.008). Patients with early epileptiform discharges developed acute seizures more frequently than patients without early epileptiform discharges (p = 0.009). Finally, functional

Early Cambrian oxygen minimum zone-like conditions at Chengjiang

NASA Astrophysics Data System (ADS)

Hammarlund, Emma U.; Gaines, Robert R.; Prokopenko, Maria G.; Qi, Changshi; Hou, Xian-Guang; Canfield, Donald E.

2017-10-01

The early Cambrian succession at Chengjiang contains the most diverse Cambrian fossil assemblage yet described, and contributes significantly to our understanding of the diversification of metazoans in the Cambrian ;explosion;. The Cambrian Period occupies a transitional episode of global ocean chemistry, following the oxygenation of the surface ocean and of shallow marine environments during the Ediacaran Period, but prior to the establishment of a predominantly oxygenated deep ocean in the mid-Paleozoic. Despite recent attention, a detailed understanding of the chemical conditions that prevailed in early Cambrian marine settings and the relationship of those conditions to early metazoan ecosystems is still emerging. Here, we report multi-proxy geochemical data from two drill cores through the early Cambrian (Series 2) Yu'anshan Formation of Yunnan, China. Results reveal dynamic water-column chemistry within the succession, which progressively shifted from euxinic to oxic conditions during deposition of the Yu'anshan Formation. The Chengjiang biota occurs in strata that appear to have been deposited under an oxygen-depleted water column that may have supported denitrification, as in modern oxygen-minimum zones. The oxygenated benthic environments in which the Chengjiang biota thrived were proximal to, but sharply separated from, the open ocean by a persistent anoxic water mass that occupied a portion of the outer shelf. Oxygen depletion in the lower water column developed dynamically in response to nutrient availability and possibly at lower thresholds of productivity due to lower atmospheric oxygen concentrations in Cambrian. These findings suggest that the frequent development of oxygen-limiting conditions in continental margin settings provided an environmental barrier that may have affected biogeographic, ecological and evolutionary development of early metazoan communities.

[Soil seed bank formation during early revegetation of areas affected by mining in a tropical rain forest of Chocó, Colombia].

PubMed

Valois-Cuesta, Hamleth; Martínez-Ruiz, Carolina; Urrutia-Rivas, Yorley

2017-03-01

Mining is one of the main economic activities in many tropical regions and is the cause of devastation of large areas of natural tropical forests. The knowledge of the regenerative potential of mining disturbed areas provides valuable information for their ecological restoration. The aim of this study was to evaluate the effect of age of abandonment of mines and their distance from the adjacent forest, on the formation of soil seed bank in abandoned mines in the San Juan, Chocó, Colombia. To do this, we determined the abundance and species composition of the soil seed bank, and the dynamics of seed rain in mines of different cessation period of mining activity (6 and 15 years), and at different distances from the adjacent forest matrix (50 and 100 m). Seed rain was composed by five species of plants with anemocorous dispersion, and was more abundant in the mine of 6 years than in the mine of 15 years. There were no significant differences in the number of seeds collected at 50 m and 100 m from the adjacent forest. The soil seed bank was represented by eight species: two with anemocorous dispersion (common among the seed rain species) and the rest with zoochorous dispersion. The abundance of seeds in the soil did not vary with the age of the mine, but was higher at close distances to the forest edge than far away. During the early revegetation, the formation of the soil seed bank in the mines seems to be related to their proximity to other disturbed areas, rather than their proximity to the adjacent forest or the cessation activity period of mines. Therefore, the establishment of artificial perches or the maintenance of isolated trees in the abandoned mines could favour the arrival of bird-dispersed seeds at mines. However, since the soil seed bank can be significantly affected by the high rainfall in the study area, more studies are needed to evaluate management actions to encourage soil seed bank formation in mines of high-rainfall environments in the Choc

Promoting healthy food preferences from the start: a narrative review of food preference learning from the prenatal period through early childhood.

PubMed

Anzman-Frasca, S; Ventura, A K; Ehrenberg, S; Myers, K P

2018-04-01

The palatable, energy-dense foods that characterize modern environments can promote unhealthy eating habits, along with humans' predispositions to accept sweet tastes and reject those that are sour or bitter. Yet food preferences are malleable, and examining food preference learning during early life can highlight ways to promote acceptance of healthier foods. This narrative review describes research from the past 10 years focused on food preference learning from the prenatal period through early childhood (ages 2-5 years). Exposure to a variety of healthy foods from the start, including during the prenatal period, early milk-feeding and the introduction to complementary foods and beverages, can support subsequent acceptance of those foods. Yet development is plastic, and healthier food preferences can still be promoted after infancy. In early childhood, research supports starting with the simplest strategies, such as repeated exposure and modelling, reserving other strategies for use when needed to motivate the initial tasting necessary for repeated exposure effects to begin. This review can help caregivers and practitioners to promote the development of healthy food preferences early in life. Specific implementation recommendations, the role of individual differences and next steps for research in this area are also discussed. © 2017 World Obesity Federation.

Early assembly of the most massive galaxies.

PubMed

Collins, Chris A; Stott, John P; Hilton, Matt; Kay, Scott T; Stanford, S Adam; Davidson, Michael; Hosmer, Mark; Hoyle, Ben; Liddle, Andrew; Lloyd-Davies, Ed; Mann, Robert G; Mehrtens, Nicola; Miller, Christopher J; Nichol, Robert C; Romer, A Kathy; Sahlén, Martin; Viana, Pedro T P; West, Michael J

2009-04-02

The current consensus is that galaxies begin as small density fluctuations in the early Universe and grow by in situ star formation and hierarchical merging. Stars begin to form relatively quickly in sub-galactic-sized building blocks called haloes which are subsequently assembled into galaxies. However, exactly when this assembly takes place is a matter of some debate. Here we report that the stellar masses of brightest cluster galaxies, which are the most luminous objects emitting stellar light, some 9 billion years ago are not significantly different from their stellar masses today. Brightest cluster galaxies are almost fully assembled 4-5 billion years after the Big Bang, having grown to more than 90 per cent of their final stellar mass by this time. Our data conflict with the most recent galaxy formation models based on the largest simulations of dark-matter halo development. These models predict protracted formation of brightest cluster galaxies over a Hubble time, with only 22 per cent of the stellar mass assembled at the epoch probed by our sample. Our findings suggest a new picture in which brightest cluster galaxies experience an early period of rapid growth rather than prolonged hierarchical assembly.

Megadontia, striae periodicity and patterns of enamel secretion in Plio-Pleistocene fossil hominins

PubMed Central

Lacruz, Rodrigo S; Dean, M Christopher; Ramirez-Rozzi, Fernando; Bromage, Timothy G

2008-01-01

Early hominins formed large and thick-enamelled cheek-teeth within relatively short growth periods as compared with modern humans. To understand better the developmental basis of this process, we measured daily enamel increments, or cross striations, in 17 molars of Plio-Pleistocene hominins representing seven different species, including specimens attributed to early Homo. Our results show considerable variation across species, although all specimens conformed to the known pattern characterised by greater values in outer than inner enamel, and greater cuspal than cervical values. We then compared our results with the megadontia index, which represents tooth size in relation to body mass, for each species to assess the effect of daily growth rates on tooth size. Our results indicate that larger toothed (megadont) taxa display higher rates or faster forming enamel than smaller toothed hominins. By forming enamel quickly, large tooth crowns were able to develop within the constraints of shorter growth periods. Besides daily increments, many animals express long-period markings (striae of Retzius) in their enamel. We report periodicity values (number of cross striations between adjacent striae) in 14 new specimens of Australopithecus afarensis, Paranthropus aethiopicus, Paranthropus boisei, Homo habilis, Homo rudolfensis and Homo erectus, and show that long-period striae express a strong association with male and average male–female body mass. Our results for Plio-Pleistocene hominins show that the biological rhythms that give rise to long-period striae are encompassed within the range of variation known for modern humans, but show a lower mean and modal value of 7 days in australopithecines. In our sample of early Homo, mean and modal periodicity values were 8 days, and therefore similar to modern humans. These new data on daily rates of enamel formation and periodicity provide a better framework to interpret surface manifestations of internal growth markings on

Megadontia, striae periodicity and patterns of enamel secretion in Plio-Pleistocene fossil hominins.

PubMed

Lacruz, Rodrigo S; Dean, M Christopher; Ramirez-Rozzi, Fernando; Bromage, Timothy G

2008-08-01

Early hominins formed large and thick-enamelled cheek-teeth within relatively short growth periods as compared with modern humans. To understand better the developmental basis of this process, we measured daily enamel increments, or cross striations, in 17 molars of Plio-Pleistocene hominins representing seven different species, including specimens attributed to early Homo. Our results show considerable variation across species, although all specimens conformed to the known pattern characterised by greater values in outer than inner enamel, and greater cuspal than cervical values. We then compared our results with the megadontia index, which represents tooth size in relation to body mass, for each species to assess the effect of daily growth rates on tooth size. Our results indicate that larger toothed (megadont) taxa display higher rates or faster forming enamel than smaller toothed hominins. By forming enamel quickly, large tooth crowns were able to develop within the constraints of shorter growth periods. Besides daily increments, many animals express long-period markings (striae of Retzius) in their enamel. We report periodicity values (number of cross striations between adjacent striae) in 14 new specimens of Australopithecus afarensis, Paranthropus aethiopicus, Paranthropus boisei, Homo habilis, Homo rudolfensis and Homo erectus, and show that long-period striae express a strong association with male and average male-female body mass. Our results for Plio-Pleistocene hominins show that the biological rhythms that give rise to long-period striae are encompassed within the range of variation known for modern humans, but show a lower mean and modal value of 7 days in australopithecines. In our sample of early Homo, mean and modal periodicity values were 8 days, and therefore similar to modern humans. These new data on daily rates of enamel formation and periodicity provide a better framework to interpret surface manifestations of internal growth markings on

Vision-Based Sensor for Early Detection of Periodical Defects in Web Materials

PubMed Central

Bulnes, Francisco G.; Usamentiaga, Rubén; García, Daniel F.; Molleda, Julio

2012-01-01

During the production of web materials such as plastic, textiles or metal, where there are rolls involved in the production process, periodically generated defects may occur. If one of these rolls has some kind of flaw, it can generate a defect on the material surface each time it completes a full turn. This can cause the generation of a large number of surface defects, greatly degrading the product quality. For this reason, it is necessary to have a system that can detect these situations as soon as possible. This paper presents a vision-based sensor for the early detection of this kind of defects. It can be adapted to be used in the inspection of any web material, even when the input data are very noisy. To assess its performance, the sensor system was used to detect periodical defects in hot steel strips. A total of 36 strips produced in ArcelorMittal Avilés factory were used for this purpose, 18 to determine the optimal configuration of the proposed sensor using a full-factorial experimental design and the other 18 to verify the validity of the results. Next, they were compared with those provided by a commercial system used worldwide, showing a clear improvement. PMID:23112629

All that glitters: fool's gold in the early-modern era.

PubMed

Roos, Anna Marie

2008-12-01

Natural philosophers of the early-modern period perceived fool's gold or iron pyrites as a substance required for the formation of metals, and chemists such as Johann Glauber speculated the vitriol produced from pyrites was the source of the legendary philosopher's stone. The sulphurous exhalations of fool's gold were also thought by members of the early Royal Society to be the basis of a variety of meteorological, geological and medical effects, including the production of thunder, lightning, earthquakes and volcanoes, fossilisation and petrifaction, as well as the principal cause of bladder and gallstones.

[Determination of nosocomial infection incidence in mothers and newborns during the early postpartum period].

PubMed

Malavaud, S; Bou-Segonds, E; Berrebi, A; Castagno, R; Assouline, C; Connan, L

2003-04-01

We wished to determine the incidence of nosocomial infections in the mother and the newborn during the early postpartum period. Over a three-month period, the same investigator collected 50 different clinical and microbiological, standardized data related to infectious diseases in parturients and their newborns. Data were collected on 804 deliveries. The overall rate of nosocomial infection was 2.9% (23/804). For vaginal deliveries, the rate was 1.9% (12/615) and for deliveries by Cesarean section, the rate was 5.8% (11/189). Of 745 newborns followed until discharge from hospital, 0.7% (5/745) had a nosocomial infection. These results are in line with previously published rates of nosocomial infections, which varied between 0.2% to 2.3% for vaginal deliveries, 1.6% to 18.9% for Cesarean section, and 0.2 to 4% in newborns. Regular surveys of the incidence or the prevalence of nosocomial infections are necessary to monitor the effectiveness of educational programs, aimed to reduce hospital acquired infections.

Geology of the Early Arikareean sharps formation on the Pine Ridge Indian Reservation and surrounding areas of South Dakota and Nebraska.

PubMed

McConnell, Thomas H; Dibenedetto, Joseph N

2012-01-01

Based on geologic mapping, measured sections, and lithologic correlations, the local features of the upper and lower type areas of the Early Arikareean (30.8-20.6 million years ago) Sharps Formation are revised and correlated. The Sharps Formation above the basal Rockyford Member is divided into two members of distinct lithotypes. The upper 233 feet of massive siltstones and sandy siltstones is named the Gooseneck Road Member. The middle member, 161 feet of eolian volcaniclastic siltstones with fluvially reworked volcaniclastic lenses and sandy siltstone sheets, is named the Wolff Camp Member. An ashey zone at the base of the Sharps Formation is described and defined as the Rockyford Ash Zone (RAZ) in the same stratigraphic position as the Nonpareil Ash Zone (NPAZ) in Nebraska. Widespread marker beds of fresh water limestones at 130 feet above the base of the Sharps Formation and a widespread reddish-brown clayey siltstone at 165 feet above the base of the Sharps Formation are described. The Brown Siltstone Beds of Nebraska are shown to be a southern correlative of the Wolff Camp Member and the Rockyford Member of the Sharps Formation. Early attempts to correlate strata in the Great Plains were slow in developing. Recognition of the implications of the paleomagnetic and lithologic correlations of this paper will provide an added datum assisting researchers in future biostratigraphic studies. Based on similar lithologies, the Sharps Formation, currently assigned to the Arikaree Group, should be reassigned to the White River Group.

The Formation of Haze During the Rise of Oxygen in the Atmosphere of the Early Earth

NASA Astrophysics Data System (ADS)

Horst, S. M.; Jellinek, M.; Pierrehumbert, R.; Tolbert, M. A.

2013-12-01

Atmospheric aerosols play an important role in determining the radiation budget of an atmosphere and can also provide a wealth of organic material to the surface. Photochemical hazes are abundant in reducing atmospheres, such as the N2/CH4 atmosphere of Titan, but are unlikely to form in oxidizing atmospheres, such as the N2/O2 atmosphere of present day Earth. However, information about haze formation in mildly oxidizing atmospheres is lacking. Understanding haze formation in mildly oxidizing atmospheres is necessary for models that wish to investigate the atmosphere of the Early Earth as O2 first appeared and then increased in abundance. Previous studies of the atmosphere of the Early Earth have focused on haze formation in N2/CO2/CH4 atmospheres. In this work, we experimentally investigate the effect of the addition of O2 on the formation and composition of aerosols. Using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) (see e.g. [1]) we have obtained in situ composition measurements of aerosol particles produced in N2/CO2/CH4/O2 gas mixtures subjected to FUV radiation (deuterium lamp, 115-400 nm) for a range of initial CO2/CH4/O2 mixing ratios. In particular, we studied the effect of O2 ranging from 2 ppm to 2%. The particles were also investigated using a Scanning Mobility Particle Sizer (SMPS), which measures particle size, number density and mass loading. A comparison of the composition of the aerosols will be presented. The effect of variation of O2 mixing ratio on aerosol production, size, and composition will also be discussed. [1] Trainer, M.G., et al. (2012) Astrobiology, 12, 315-326.

Role of nanoparticles generation in the formation of femtosecond laser-induced periodic surface structures on silicon.

PubMed

Xue, Hongyan; Deng, Guoliang; Feng, Guoying; Chen, Lin; Li, Jiaqi; Yang, Chao; Zhou, Shouhuan

2017-09-01

An initial roughness is assumed in the most accepted Sipe-Drude model to analyze laser-induced periodic surface structures (LIPSS). However, the direct experimental observation for the crucial parameters is still lacking. The generation of nanoparticles and low-spatial frequency LIPSS (LSFL) (LIPSS with a periodicity close to laser wavelength) on a silicon surface upon a single pulse and subsequent pulses irradiation, respectively, is observed experimentally. Finite-difference time-domain (FDTD) simulation indicates that the nanoparticles generated with the first pulse enhance the local electric field greatly. Based on the experimental extrapolated parameters, FDTD-η maps have been calculated. The results show that the inhomogeneous energy deposition, which leads to the formation of LSFL, is mainly from the modulation of the nanoparticles with a radius of around 100 nm.

Self-consistent formation of continents on early Earth

NASA Astrophysics Data System (ADS)

Noack, Lena; Van Hoolst, Tim; Breuer, Doris; Dehant, Véronique

2013-04-01

In our study we want to understand how Earth evolved with time and examine the initiation of plate tectonics and the possible formation of continents on Earth. Plate tectonics and continents seem to influence the likelihood of a planet to harbour life [1], and both are strongly influenced by the planetary interior (e.g. mantle temperature and rheology) and surface conditions (e.g. stabilizing effect of continents, atmospheric temperature), and may also depend on the biosphere. Earth is the only terrestrial planet (i.e. with a rocky mantle and iron core) in the solar system where long-term plate tectonics evolved. Knowing the factors that have a strong influence on the occurrence of plate tectonics allows for prognoses about plate tectonics on terrestrial exoplanets that have been detected in the past decade, and about the likelihood of these planets to harbour Earth-like life. For this purpose, planetary interior and surface processes are coupled via 'particles' as computational tracers in the 3D code GAIA [2,3]. These particles are dispersed in the mantle and crust of the modelled planet and can track the relevant rock properties (e.g. density or water content) over time. During the thermal evolution of the planet, the particles are advected due to mantle convection and along melt paths towards the surface and help to gain information about the thermo-chemical system. This way basaltic crust that is subducted into the silicate mantle is traced in our model. It is treated differently than mantle silicates when re-molten, such that granitic (felsic) crust is produced (similar to the evolution of continental crust on early Earth [4]), which is stored in the particle properties. We apply a pseudo-plastic rheology and use small friction coefficients (since an increased reference viscosity is used in our model). We obtain initiation of plate tectonics and self-consistent formation of pre-continents after a few Myr up to several Gyr - depending on the initial conditions

Formation mechanisms of periodic longitudinal microstructure and texture patterns in friction stir welded magnesium AZ80

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hiscocks, J., E-mail: j.hiscocks@queensu.ca

Many studies of friction stir welding have shown that periodicity of metal flow around the tool pin may result in the formation of periodic differences in microstructure and texture in the weld nugget area correlated with the weld pitch. The current work investigates the periodicity of magnesium weld microtexture in the nugget region and its association with material flow using optical and electron microscopy. Two welds created in AZ80 at different processing conditions are presented in detail, one illustrating periodic longitudinal texture change, and one showing for the first time that periodic variations in texture, grain size, or composition aremore » not defining features of periodic nugget flow. While nugget texture is dominated by shear deformation, it was found here to be affected to a lesser degree by compaction of material behind the welding tool, which led to reduction in intensity of the shear texture fiber. The decreased tendency for magnesium based alloys to form periodic patterns as compared to aluminum based alloys is explained with reference to the shear textures. - Highlights: •It is shown here that periodic material flow in the nugget does not necessitate longitudinal texture patterns. •Longitudinal texture patterns are shown to be present or absent in Mg AZ80 based on processing conditions. •Texture in the nugget is mainly dictated by shear deformation, but has measurable effects from other deformation modes. •Explanation of why longitudinal texture change is frequently reported in aluminum but not magnesium alloys is provided. •A new vector visualization of material flow based on EBSD data analysis is shown.« less

The Preboreal-like Asian monsoon climate in the early last interglacial period recorded from the Dark Cave, Southwest China

NASA Astrophysics Data System (ADS)

Jiang, Xiuyang; He, Yaoqi; Wang, Xiaoyan; Sun, Xiaoshuang; Hong, Hui; Liu, Juan; Yu, Tsai-Luen; Li, Zhizhong; Shen, Chuan-Chou

2017-08-01

Transitions of glacial-interglacial cycles are critical periods for Quaternary climate shifts. Here, we present new, decadal resolution Asian summer monsoon (ASM) record from three stalagmites obtained from the Dark Cave in southwestern China over 130-114 thousand years ago (ka, before CE 1950). Chronology was anchored by 28 230Th dates with typical uncertainties of ±0.3-1.0 kyr, allowing an assessment of timing and transition of climate changes during the onset and end of the last interglacial. An agreement between this new and previous stalagmite δ18O records supports that summer insolation predominates orbital-scale ASM evolution. A 2-3 kyr-long gradually increasing ASM period, analogous to the classical Preboreal episode in the early Holocene, follows the termination of a weak monsoon interval at 129.0 ± 0.8 ka. This finding suggests a strong influence of high-latitude ice-sheet dynamics on Asian monsoonal conditions during the early interglacial period. An abrupt end of the marine isotope stage 5e at 118.8 ± 0.6 ka was probably caused by the internal climate system threshold effects.

Effects of nutrient optimization on intra-annual wood formation in Norway spruce.

PubMed

Kalliokoski, Tuomo; Mäkinen, Harri; Jyske, Tuula; Nöjd, Pekka; Linder, Sune

2013-11-01

In the Nordic countries, growth of Norway spruce (Picea abies (L.) Karst.) is generally limited by low availability of nutrients, especially nitrogen. Optimizing forest management requires better insight on how growth responds to the environmental conditions and their manipulation. The aim of this study was to analyse the effects of nutrient optimization on timing and the rate of tracheid formation of Norway spruce and to follow the differentiation of newly formed tracheids. The study was performed during two growing seasons in a long-term nutrient optimization experiment in northern Sweden, where all essential macro- and micronutrients were supplied in irrigation water every second day from mid-June to mid-August. The control plots were without additional nutrients and water. Tracheid formation in the stem was monitored throughout the growing season by weekly sampling of microcores at breast height. The onset of xylogenesis occurred in early June, but in early summer there were no significant between-treatment differences in the onset and relative rate of tracheid formation. In both treatments, the onset of secondary cell wall formation occurred in mid-June. The maximum rate of tracheid formation occurred close to the summer solstice and 50% of the tracheids had been accumulated in early July. Optimized nutrition resulted in the formation of ∼50% more tracheids and delayed the cessation of tracheid formation, which extended the tracheid formation period by 20-50%, compared with control trees. The increased growth was mainly an effect of enhanced tracheid formation rate during the mid- and later-part of the growing season. In the second year, the increased growth rate also resulted in 11% wider tracheids. We conclude that the onset and rate of tracheid formation and differentiation during summer is primarily controlled by photoperiod, temperature and availability of nutrients, rather than supply of carbohydrates.

Directly dated starch residues document early formative maize (Zea mays L.) in tropical Ecuador

PubMed Central

Zarrillo, Sonia; Pearsall, Deborah M.; Raymond, J. Scott; Tisdale, Mary Ann; Quon, Dugane J.

2008-01-01

The study of maize (Zea mays L.) domestication has advanced from questions of its origins to the study—and debate—of its dietary role and the timing of its dispersal from Mexico. Because the investigation of maize's spread is hampered by poor preservation of macrobotanical remains in the Neotropics, research has focused on microbotanical remains whose contexts are often dated by association, leading some to question the dates assigned. Furthermore, some scholars have argued that maize was not introduced to southwestern Ecuador until ≈4150–3850 calendar years before the present (cal B.P.), that it was used first and foremost as a fermented beverage in ceremonial contexts, and that it was not important in everyday subsistence, challenging previous studies based on maize starch and phytoliths. To further investigate these questions, we analyzed every-day cooking vessels, food-processing implements, and sediments for starch and phytoliths from an archaeological site in southwestern Ecuador constituting a small Early Formative village. Employing a new technique to recover starch granules from charred cooking-pot residues we show that maize was present, cultivated, and consumed here in domestic contexts by at least 5300–4950 cal B.P. Directly dating the residues by accelerator mass spectrometry (AMS) radiocarbon measurement, our results represent the earliest direct dates for maize in Early Formative Ecuadorian sites and provide further support that, once domesticated ≈9000 calendar years ago, maize spread rapidly from southwestern Mexico to northwestern South America. PMID:18362336

[Intrauterine devices in the immediate, early and late postabortion period].

PubMed

Nun, S

1971-01-01

2146 cases of IUD insertions after hospitalization for abortion at a hospital in Chile were studied. In 1514 cases the IUDs were inserted immediately after abortion, in 430 cases between 1-5 days after the operation, and in 202 cases between 5-40 days after. It is concluded that immediate or early insertion results in a somewhat lower retention rate, but offers the advantage of making it possible to treat a greater number of patients, many of whom would not return later to have the IUD inserted. The incidence of removal for medical causes was very low and immediate insertion was found to be harmless. The medical causes of removal were the usual ones of bleeding, pain, and infection; the most frequent cause of interruption of use was expulsion, which tends to occur during the 1st few months of use and among younger women. The probability of failure due to pregnancy was somewhat higher than in the case of insertion during the intermenstrual period. Cases of voluntary removal tend to increase after prolonged use, and a study to analyze the actual reasons for this fact is necessary.

The Early Identity Exploration Scale-a measure of initial exploration in breadth during early adolescence.

PubMed

Kłym, Maria; Cieciuch, Jan

2015-01-01

The existing models and measurement instruments concerning identity appear to primarily focus on adolescence and early adulthood, and studies extending identity research to younger stages of life are scarce. There has been a particular lack of instruments measuring the early stages of identity formation, especially the process of exploration, which has been portrayed as a central process during this particular period of life. Our aim is to help fill the gap in the literature and facilitate further studies of the exploration process by providing an appropriate instrument to measure exploration in breadth during early adolescence. As a coherent and mature sense of identity is closely associated with psychosocial well-being, an effective identity exploration scale will enable researchers to assess the predictors of young adolescents' well-being. We propose a model of identity exploration domains based on the literature and considering 12 exploration domains: physical appearance, free time, family, work, boyfriend-girlfriend relationships, own opinion formation, perception of own place in the life cycle, self-reflection, future, future family, outlook on life, and attitude toward rules. The study was conducted on a group of N = 454 adolescents (50% males, M age = 13.04, SD = 0.98). Both reliability and structural validity, as verified by confirmatory factor analysis were satisfactory. The instrument is invariant across gender groups at the scalar level of measurement invariance.

The Early Identity Exploration Scale—a measure of initial exploration in breadth during early adolescence

PubMed Central

Kłym, Maria; Cieciuch, Jan

2015-01-01

The existing models and measurement instruments concerning identity appear to primarily focus on adolescence and early adulthood, and studies extending identity research to younger stages of life are scarce. There has been a particular lack of instruments measuring the early stages of identity formation, especially the process of exploration, which has been portrayed as a central process during this particular period of life. Our aim is to help fill the gap in the literature and facilitate further studies of the exploration process by providing an appropriate instrument to measure exploration in breadth during early adolescence. As a coherent and mature sense of identity is closely associated with psychosocial well-being, an effective identity exploration scale will enable researchers to assess the predictors of young adolescents' well-being. We propose a model of identity exploration domains based on the literature and considering 12 exploration domains: physical appearance, free time, family, work, boyfriend-girlfriend relationships, own opinion formation, perception of own place in the life cycle, self-reflection, future, future family, outlook on life, and attitude toward rules. The study was conducted on a group of N = 454 adolescents (50% males, Mage = 13.04, SD = 0.98). Both reliability and structural validity, as verified by confirmatory factor analysis were satisfactory. The instrument is invariant across gender groups at the scalar level of measurement invariance. PMID:25983707

A Guide to Dental Care for the Early and Periodic Screening, Diagnosis, and Treatment Program (EPSDT) Under Medicaid.

ERIC Educational Resources Information Center

Lindahl, Roy L.; Young, Wesley O.

This guide has been developed to assist administrators, providers of dental care, and others involved in carrying out the dental care provisions of the EPSDT program (Early and Periodic Screening, Diagnosis, and Treatment Program). It is intended to assist in the development of programs concerned with the unique characteristics of dental diseases…

[Restoring of the speech functions in patients with aphasia in the early rehabilitation period of ischemic stroke].

PubMed

Kotov, S V; Belova, Yu A; Shcherbakova, M M; Chervinskaya, A D; Isakova, E V; Volchenkova, T V

To study the efficacy of combined therapy including daily sessions and two 10-day injections of the drug cellex in patients with aphasia in the early rehabilitation period of ischemic stroke (II). Forty patients in the early rehabilitation period of II in the basin of the left middle cerebral artery with moderate to severe aphasia were studied. Twenty patients received combined therapy, including daily sessions with a speech therapist-aphasiologist within 10 days using the improved method, then a self-study using educational materials and two 10-day injections of cellex. Other 20 patients received only speech therapy. To assess the efficacy of therapy, the automated "Program of examination of patients with aphasia", Goodglass-Kaplan scale, modified Rankin scale were used. There was a significant improvement of speech functions, communicative abilities and functional recovery (p<0.01) in patients of both groups. However, a significantly greater level of rehabilitation (p<0.05) was noted in patients treated with combined therapy included two courses of cellex. The results allow to recommend the inclusion of cellex in the complex rehabilitation of patients with post-stroke speech disorders.

Formation of thermochemical laser-induced periodic surface structures on Ti films by a femtosecond IR Gaussian beam: regimes, limiting factors, and optical properties

NASA Astrophysics Data System (ADS)

Dostovalov, A. V.; Korolkov, V. P.; Babin, S. A.

2017-01-01

The formation of thermochemical laser-induced periodic surface structures (TLIPSS) on 400-nm Ti films deposited onto a glass substrate is investigated under irradiation by a femtosecond laser with a wavelength of 1026 nm, pulse duration of 232 fs, repetition rate of 200 kHz, and with different spot sizes of 4-21 μm. The optimal fluence for TLIPSS formation reduces monotonously with increasing the spot diameter in the range. It is found that the standard deviation of the TLIPSS period depends significantly on the beam size and reaches approximately 2% when the beam diameter is in the range of 10-21 μm. In addition to TLIPSS formation with the main period slightly smaller than the laser wavelength, an effect of TLIPSS spatial frequency doubling is detected. The optical properties of TLIPSS (reflection spectrum and diffraction efficiency at different incident angles and polarizations) are investigated and compared with theoretical ones to give a basis for the development of an optical inspecting method. The refractive index and absorption coefficient of oxidized ridges of the TLIPSS are theoretically estimated by simulation of the experimental reflection spectrum in the zeroth diffraction order.

Early events in xenograft development from the human embryonic stem cell line HS181--resemblance with an initial multiple epiblast formation.

PubMed

Gertow, Karin; Cedervall, Jessica; Jamil, Seema; Ali, Rouknuddin; Imreh, Marta P; Gulyas, Miklos; Sandstedt, Bengt; Ahrlund-Richter, Lars

2011-01-01

Xenografting is widely used for assessing in vivo pluripotency of human stem cell populations. Here, we report on early to late events in the development of mature experimental teratoma from a well-characterized human embryonic stem cell (HESC) line, HS181. The results show an embryonic process, increasingly chaotic. Active proliferation of the stem cell derived cellular progeny was detected already at day 5, and characterized by the appearance of multiple sites of engraftment, with structures of single or pseudostratified columnar epithelium surrounding small cavities. The striking histological resemblance to developing embryonic ectoderm, and the formation of epiblast-like structures was supported by the expression of the markers OCT4, NANOG, SSEA-4 and KLF4, but a lack of REX1. The early neural marker NESTIN was uniformly expressed, while markers linked to gastrulation, such as BMP-4, NODAL or BRACHYURY were not detected. Thus, observations on day 5 indicated differentiation comparable to the most early transient cell populations in human post implantation development. Confirming and expanding on previous findings from HS181 xenografts, these early events were followed by an increasingly chaotic development, incorporated in the formation of a benign teratoma with complex embryonic components. In the mature HS181 teratomas not all types of organs/tissues were detected, indicating a restricted differentiation, and a lack of adequate spatial developmental cues during the further teratoma formation. Uniquely, a kinetic alignment of rare complex structures was made to human embryos at diagnosed gestation stages, showing minor kinetic deviations between HS181 teratoma and the human counterpart.

The ATLAS3D Project - XXX. Star formation histories and stellar population scaling relations of early-type galaxies

NASA Astrophysics Data System (ADS)

McDermid, Richard M.; Alatalo, Katherine; Blitz, Leo; Bournaud, Frédéric; Bureau, Martin; Cappellari, Michele; Crocker, Alison F.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

2015-04-01

We present the stellar population content of early-type galaxies from the ATLAS3D survey. Using spectra integrated within apertures covering up to one effective radius, we apply two methods: one based on measuring line-strength indices and applying single stellar population (SSP) models to derive SSP-equivalent values of stellar age, metallicity, and alpha enhancement; and one based on spectral fitting to derive non-parametric star formation histories, mass-weighted average values of age, metallicity, and half-mass formation time-scales. Using homogeneously derived effective radii and dynamically determined galaxy masses, we present the distribution of stellar population parameters on the Mass Plane (MJAM, σe, R^maj_e), showing that at fixed mass, compact early-type galaxies are on average older, more metal-rich, and more alpha-enhanced than their larger counterparts. From non-parametric star formation histories, we find that the duration of star formation is systematically more extended in lower mass objects. Assuming that our sample represents most of the stellar content of today's local Universe, approximately 50 per cent of all stars formed within the first 2 Gyr following the big bang. Most of these stars reside today in the most massive galaxies (>1010.5 M⊙), which themselves formed 90 per cent of their stars by z ˜ 2. The lower mass objects, in contrast, have formed barely half their stars in this time interval. Stellar population properties are independent of environment over two orders of magnitude in local density, varying only with galaxy mass. In the highest density regions of our volume (dominated by the Virgo cluster), galaxies are older, alpha-enhanced, and have shorter star formation histories with respect to lower density regions.

Full-Thickness Macular Hole Formation in the Postoperative Period After Initial Vitrectomy for Rhegmatogenous Retinal Detachment.

PubMed

Takashina, Hirotsugu; Watanabe, Akira; Tsuneoka, Hiroshi

2017-01-01

To evaluate full-thickness macular hole (MH) formation in the postoperative period after initial vitrectomy for rhegmatogenous retinal detachment (rRD). We retrospectively reviewed the medical records of 4 consecutive eyes that required additional vitrectomy for full-thickness MH between April 2013 and March 2016 after undergoing an initial vitrectomy for rRD. Epiretinal membrane (ERM) was identified by preoperative optical coherence tomography or intraoperative dye staining in each case. Photocoagulation of retinal breaks prior to initial vitrectomy was performed in Cases 1, 2, and 3 (4-16 days), with yttrium-aluminum-garnet capsulotomy after cataract extraction also performed prior to the retinal break formation in Case 3. At the initial vitrectomy, there was a superior retinal break which crossed the equator in Case 2, and an intentional hole was created in Cases 1 and 4. The mean interval from the initial vitrectomy until MH formation was 27.5 ± 15.8 months. As with Case 2, the intervals in Cases 1 and 4, in which an intentional hole was created, were clearly shorter than in those in Case 3. Finally, MH closure was achieved after an additional vitrectomy (removal of the internal limiting membrane with ERM and gas tamponade) and best-corrected visual acuity improved in each case. ERM was identified in the cases examined in our study. The presence of an intentional hole might shorten the interval of MH formation after vitrectomy for rRD.

Formation of periodic mesoscale structures arranged in a circular symmetry at the silicon surface exposed to radiation of a single femtosecond laser pulse

NASA Astrophysics Data System (ADS)

Romashevskiy, S. A.; Ashitkov, S. I.; Ovchinnikov, A. V.; Kondratenko, P. S.; Agranat, M. B.

2016-06-01

The periodic mesoscale structures arranged in a circular symmetry were found at the silicon surface exposed to radiation of the single femtosecond laser pulse with a Gaussian intensity profile in the ambient air conditions. These peculiar structures have the appearance of the protrusions of ∼10 nm height and of ∼600 nm width (at a FWHM) separately located inside the ablated region with a period of the incident laser wavelength. It was found that their position at the surface corresponds to the specified laser intensity slightly above the ablation threshold. The number of the formed periodic structures varies with the fluence of the incident laser pulse and in our experiments it was found to have changed from one to eleven. We suppose that formation of these mesoscale structures is caused by heating of a microscale volume to the strongly defined temperature. The theoretical model was proposed to explain the obtained data. It assumes that the interference of incident laser radiation with laser-induced surface electromagnetic waves results in generation of periodic distribution of electron temperature. Thus formation of the periodic structures at the specified laser intensity is attributed to periodically modulated absorption of laser energy at a focal laser spot.

Formation of the metal and energy-carrier price clusters on the world market of nonferrous metals in the postcrisis period

NASA Astrophysics Data System (ADS)

Bogdanov, S. V.; Shevelev, I. M.; Chernyi, S. A.

2016-06-01

The laws of formation of price clusters are revealed upon statistical processing of the data on changing the quotation prices of nonferrous and precious metals, oil, black oil, gasoline, and natural gas in the postcrisis period from January 1, 2009 to November 1, 2013. It is found that the metal prices entering in the price cluster of nonferrous metals most strongly affect the formation of the nonferrous metal price and that the prices of precious metals and energy carriers correct the exchange price of the metal to some extent but do not determine its formation. Equations are derived to calculate the prices. The results of calculation by these equations agree well with the real nonferrous metal prices in the near future.

Self-mixing magma in the Ruiz Peak rhyodacite (New Mexico, USA): A mechanism explaining the formation of long period polytypes of mica

NASA Astrophysics Data System (ADS)

Pignatelli, I.; Faure, F.; Mosser-Ruck, R.

2016-12-01

The rhyodacite of Ruiz Peak Volcano (New Mexico, USA) is an exceptional rock because it contains both long period and short period polytypes of mica. Our petrographic study shows that this rhyodacite is characterized by numerous disequilibrium textures of phenocrysts (mica, amphibole, clinopyroxene, olivine and plagioclase) contained within both dark-grey and reddish coloured groundmass. The presence of two groundmasses, as well as of disequilibrium textures (reaction rims, resorption, dendritic, skeletal morphologies, etc.) suggests a complex magmatic history. These two types of groundmass are not due to a mixing of magmas but result from a degassing process during the magma ascent in the conduit. The disequilibrium textures are interpreted to be the result of small, short-lived convection cells in the magmatic chamber, which may allow crystal-crystal, crystal-spiral and spiral-spiral interactions to occur, leading to the formation of long period polytypes of mica. For the first time, the relationships between the crystallographic features of mica and the host-rock formation are underlined in this study. It follows that long period polytypes of mica can be considered markers of the complex history of magmas.

Climate change and tectonic activity during the early Pliocene Warm Period from the ostracod record at Lake Qinghai, northeastern Tibetan Plateau

NASA Astrophysics Data System (ADS)

Lu, Fengyan; An, Zhisheng; Chang, Hong; Dodson, John; Qiang, Xiaoke; Yan, Hong; Dong, Jibao; Song, Yougui; Fu, Chaofeng; Li, Xiangzhong

2017-05-01

The Early Pliocene Warm Period (EPWP, 5-3 Ma) is sometimes thought to be a useful analogue for a future warmer world, and thus the boundary conditions and drivers of climate in the EPWP may provide valuable lessons for understanding how a future warmer world might unfold. Lake Qinghai is located on the northeastern margin of the Tibetan Plateau (TP) and is affected by both Monsoon climate and Westerlies circulation. It is sensitive to the climate drivers of these systems. Its sediments, accumulated over the Cenozoic period, are a rich source of information for climate, tectonics and environmental changes of the period. We present a high-resolution ostracod record from a Lake Qinghai sediment core with a record of the period 5.10-2.60 Ma, thus covering the EPWP. Ostracods appear at 4.63 Ma and are most abundant until 3.58 Ma, while a body of water was present at the core site. This suggests a phase of humid climate and an intensified Asian Summer Monsoon (ASM), which is consistent with a warmer and wetter climate in the early Pliocene. Within this period the ostracod record shows some variabilities in lake level with deeper periods suggesting more intense ASM compared to those with shallower water. The disappearance of ostracods at 3.58 Ma may provide evidence for the uplift of Qinghai Nanshan (south of Qinghai Lake) since this is when the ASM intensified.

Periodic Colony Formation by Bacterial Species Bacillus subtilis

NASA Astrophysics Data System (ADS)

Wakita, Jun-ichi; Shimada, Hirotoshi; Itoh, Hiroto; Matsuyama, Tohey; Matsushita, Mitsugu

2001-03-01

We have investigated the periodic colony growth of bacterial species Bacillus subtilis. A colony grows cyclically with the interface repeating an advance (migration phase) and a rest (consolidation phase) alternately on a surface of semi-solid agar plate under appropriate environmental conditions, resulting in a concentric ring-like colony. It was found from macroscopic observations that the characteristic quantities for the periodic growth such as the migration time, the consolidation time and the terrace spacing do not depend so much on nutrient concentration Cn, but do on agar concentration Ca. The consolidation time was a weakly increasing function of Ca, while the migration time and the terrace spacing were, respectively, weakly and strongly decreasing function of Ca. Overall, the cycle (migration-plus-consolidation) time seems to be constant, and does not depend so much on both Cn and Ca. Microscopically, bacterial cells inside the growing front of a colony keep increasing their population during both migration and consolidation phases. It was also confirmed that their secreting surfactant called surfactin does not affect their periodic growth qualitatively, i.e., mutant cells which cannot secrete surfactin produce a concentric ring-like colony. All these results suggest that the diffusion of the nutrient and the surfactin are irrelevant to their periodic growth.

Cosmetic Outcome and Seroma Formation After Breast-Conserving Surgery With Intraoperative Radiation Therapy Boost for Early Breast Cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Senthi, Sashendra, E-mail: sashasenthi@msn.com; Link, Emma; Chua, Boon H.

2012-10-01

Purpose: To evaluate cosmetic outcome and its association with breast wound seroma after breast-conserving surgery (BCS) with targeted intraoperative radiation therapy (tIORT) boost for early breast cancer. Methods and Materials: An analysis of a single-arm prospective study of 55 patients with early breast cancer treated with BCS and tIORT boost followed by conventional whole breast radiation therapy (WBRT) between August 2003 and January 2006 was performed. A seroma was defined as a fluid collection at the primary tumor resection site identified clinically or radiologically. Cosmetic assessments using the European Organization for Research and Treatment of Cancer rating system were performedmore » at baseline before BCS and 30 months after WBRT was completed. Results: Twenty-eight patients (51%) developed a seroma, with 18 patients (33%) requiring at least 1 aspiration. Tumor location was significantly associated with seroma formation (P=.001). Ten of 11 patients with an upper inner quadrant tumor developed a seroma. Excellent or good overall cosmetic outcome at 30 months was observed in 34 patients (62%, 95% confidence interval 53%-80%). Seroma formation was not associated with the overall cosmetic result (P=.54). Conclusion: BCS with tIORT boost followed by WBRT was associated with an acceptable cosmetic outcome. Seroma formation was not significantly associated with an adverse cosmetic outcome.« less

Fred Hoyle: contributions to the theory of galaxy formation

NASA Astrophysics Data System (ADS)

Efstathiou, George

I review two fundamental contributions that Fred Hoyle made to the theory of galaxy formation. Hoyle was the first to propose that protogalaxies acquired their angular momentum via tidal torques from neighbouring perturbations during a period of gravitational instability. To my knowldege, he was also the first to suggest that the masses of galaxies could be explained by the requirement that primordial gas clouds cool radiatively on a suitable timescale. Tidal torques and cooling arguments play a central role in the modern theory of galaxy formation. It is a measure of Hoyle's breadth and inventiveness that he recognized the importance of these processes at such an early stage in the history of the subject.

EPSDT: Child Health. Child Health Information for Workers in the Medicaid Early and Periodic Screening Diagnosis and Treatment Program.

ERIC Educational Resources Information Center

Manela, Roger; And Others

One of six information booklets with accompanying training materials for the Medicaid Early and Periodic Screening Diagnosis and Treatment (EPSDT) program, this booklet describes the stages of child growth and development and some of the health problems which EPSDT clients might have. Section I describes tests commonly included in an EPSDT…

Brief periods of NREM sleep do not promote early offline gains but subsequent on-task performance in motor skill learning.

PubMed

Maier, Jonathan G; Piosczyk, Hannah; Holz, Johannes; Landmann, Nina; Deschler, Christoph; Frase, Lukas; Kuhn, Marion; Klöppel, Stefan; Spiegelhalder, Kai; Sterr, Annette; Riemann, Dieter; Feige, Bernd; Voderholzer, Ulrich; Nissen, Christoph

2017-11-01

Sleep modulates motor learning, but its detailed impact on performance curves remains to be fully characterized. This study aimed to further determine the impact of brief daytime periods of NREM sleep on 'offline' (task discontinuation after initial training) and 'on-task' (performance within the test session) changes in motor skill performance (finger tapping task). In a mixed design (combined parallel group and repeated measures) sleep laboratory study (n=17 'active' wake vs. sleep, n=19 'passive' wake vs. sleep), performance curves were assessed prior to and after a 90min period containing either sleep, active or passive wakefulness. We observed a highly significant, but state- (that is, sleep/wake)-independent early offline gain and improved on-task performance after sleep in comparison to wakefulness. Exploratory curve fitting suggested that the observed sleep effect most likely emerged from an interaction of training-induced improvement and detrimental 'time-on-task' processes, such as fatigue. Our results indicate that brief periods of NREM sleep do not promote early offline gains but subsequent on-task performance in motor skill learning. Copyright © 2017 Elsevier Inc. All rights reserved.

Transcriptome analysis on the exoskeleton formation in early developmetal stages and reconstruction scenario in growth-moulting in Litopenaeus vannamei.

PubMed

Gao, Yi; Wei, Jiankai; Yuan, Jianbo; Zhang, Xiaojun; Li, Fuhua; Xiang, Jianhai

2017-04-24

Exoskeleton construction is an important issue in shrimp. To better understand the molecular mechanism of exoskeleton formation, development and reconstruction, the transcriptome of the entire developmental process in Litopenaeus vannamei, including nine early developmental stages and eight adult-moulting stages, was sequenced and analysed using Illumina RNA-seq technology. A total of 117,539 unigenes were obtained, with 41.2% unigenes predicting the full-length coding sequence. Gene Ontology, Clusters of Orthologous Group (COG), the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and functional annotation of all unigenes gave a better understanding of the exoskeleton developmental process in L. vannamei. As a result, more than six hundred unigenes related to exoskeleton development were identified both in the early developmental stages and adult-moulting. A cascade of sequential expression events of exoskeleton-related genes were summarized, including exoskeleton formation, regulation, synthesis, degradation, mineral absorption/reabsorption, calcification and hardening. This new insight on major transcriptional events provide a deep understanding for exoskeleton formation and reconstruction in L. vannamei. In conclusion, this is the first study that characterized the integrated transcriptomic profiles cover the entire exoskeleton development from zygote to adult-moulting in a crustacean, and these findings will serve as significant references for exoskeleton developmental biology and aquaculture research.

Critical Learning Periods and Programs of Early Intervention.

ERIC Educational Resources Information Center

Magill, Richard A.

In an effort to clarify understanding of the concept of critical learning periods, this paper discusses problems that people concerned with the motor development of children have had determining relationships between critical periods and learning, and a "readiness model" is offered as a solution that could enhance understanding of critical…

Taxonomic composition and biostratigraphic value of the Early Riphean organic-walled microfossil association from the Ust'-Il'ya Formation of the Anabar Uplift, Northern Siberia

NASA Astrophysics Data System (ADS)

Sergeev, V. N.; Vorob'eva, N. G.; Petrov, P. Yu.; Semikhatov, M. A.

2017-05-01

It is demonstrated on the basis of the first monographic study of multiple and taxonomically variable organic-walled microfossils from the Ust'-Il'ya Formation of the Anabar Uplift that both prokaryotic and eukaryotic forms are present in the composition of this microbiota. They are divided into four formal groups on the basis of the specifics of the morphological indicators of the identified taxa. The review of the data on the isotopic age of hosting deposits showed that the Ust'-Il'ya Formation is of the Early Riphean in age which are currently evaluated as 1750 ± 10-1400 Ma. Relatively large and morphologically complex eukaryotic forms present in the Ust'-Il'ya Formation served in due time as the basis for an erroneous conclusion on the Late Riphean age of the specified formation and the overlying Lower Kotuikan Subformation of the Anabar Uplift. The paper provides a global comparative analysis of the Early Riphean microbiotas, demonstrates the position of the Ust'-Il'ya and Kotuikan microbiotas amidst the microbiotas of the same age, and shows that the relatively large acanthomorphic acritarchs Tappania, Valeria, Dictiosphaera, Satka, and Shuiyousphaeridium appeared in the geological history already during the Early Riphean Erathem. Moreover, the paper discusses the recently published data on the distribution of aerobic and anaerobic conditions in the Early Riphean paleobasins and provides the conclusion on the impact of the lateral change of these conditions on the taxonomic composition of the microbiota.

Early MRI changes in glioblastoma in the period between surgery and adjuvant therapy.

PubMed

Farace, Paolo; Amelio, Dante; Ricciardi, Giuseppe K; Zoccatelli, Giada; Magon, Stefano; Pizzini, Francesca; Alessandrini, Franco; Sbarbati, Andrea; Amichetti, Maurizio; Beltramello, Alberto

2013-01-01

To investigate the increase in MRI contrast enhancement (CE) occurring in glioblastoma during the period between surgery and initiation of chemo-radiotherapy, thirty-seven patients with newly diagnosed glioblastoma were analyzed by early post-operative magnetic resonance (EPMR) imaging within three days of surgery and by pre-adjuvant magnetic resonance (PAMR) examination before adjuvant therapy. Areas of new CE were investigated by use of EPMR diffusion-weighted imaging and PAMR perfusion imaging (by arterial spin-labeling). PAMR was acquired, on average, 29.9 days later than EPMR (range 20-37 days). During this period an increased area of CE was observed for 17/37 patients. For 3/17 patients these regions were confined to areas of reduced EPMR diffusion, suggesting postsurgical infarct. For the other 14/17 patients, these areas suggested progression. For 11/17 patients the co-occurrence of hyperperfusion in PAMR perfusion suggested progression. PAMR perfusion and EPMR diffusion did not give consistent results for 3/17 patients for whom small new areas of CE were observed, presumably because of the poor spatial resolution of perfusion imaging. Before initiation of adjuvant therapy, areas of new CE of resected glioblastomas are frequently observed. Most of these suggest tumor progression, according to EPMR diffusion and PAMR perfusion criteria.

Monkey primary somatosensory cortical activity during the early reaction time period differs with cues that guide movements.

PubMed

Liu, Yu; Denton, John M; Nelson, Randall J

2008-05-01

Vibration-related neurons in monkey primary somatosensory cortex (SI) discharge rhythmically when vibratory stimuli are presented. It remains unclear how functional information carried by vibratory inputs is coded in rhythmic neuronal activity. In the present study, we compared neuronal activity during wrist movements in response to two sets of cues. In the first, movements were guided by vibratory cue only (VIB trials). In the second, movements were guided by simultaneous presentation of both vibratory and visual cues (COM trials). SI neurons were recorded extracellularly during both wrist extensions and flexions. Neuronal activity during the instructed delay period (IDP) and the early reaction time period (RTP) were analyzed. A total of 96 cases from 48 neurons (each neuron contributed two cases, one each for extension and flexion) showed significant vibration entrainment during the early RTPs, as determined by circular statistics (Rayleigh test). Of these, 50 cases had cutaneous (CUTA) and 46 had deep (DEEP) receptive fields. The CUTA neurons showed lower firing rates during the IDPs and greater firing rate changes during the early RTPs when compared with the DEEP neurons. The CUTA neurons also demonstrated decreases in activity entrainment during VIB trials when compared with COM trials. For the DEEP neurons, the difference of entrainment between VIB and COM trials was not statistically significant. The results suggest that somatic vibratory input is coded by both the firing rate and the activity entrainment of the CUTA neurons in SI. The results also suggest that when vibratory inputs are required for successful task completion, the activity of the CUTA neurons increases but the entrainment degrades. The DEEP neurons may be tuned before movement initiation for processing information encoded by proprioceptive afferents.

Measuring professional identity formation early in medical school.

PubMed

Kalet, Adina; Buckvar-Keltz, Lynn; Harnik, Victoria; Monson, Verna; Hubbard, Steven; Crowe, Ruth; Song, Hyuksoon S; Yingling, Sandra

2017-03-01

To assess the feasibility and utility of measuring baseline professional identity formation (PIF) in a theory-based professionalism curriculum for early medical students. All 132 entering students completed the professional identity essay (PIE) and the defining issues test (DIT2). Students received score reports with individualized narrative feedback and wrote a structured reflection after a large-group session in which the PIF construct was reviewed. Analysis of PIEs resulted in assignment of a full or transitional PIF stage (1-5). The DIT2 score reflects the proportion of the time students used universal ethical principles to justify a response to 6 moral dilemma cases. Students' reflections were content analyzed. PIF scores were distributed across stage 2/3, stage 3, stage 3/4, and stage 4. No student scores were in stages 1, 2, 4/5, or 5. The mean DIT2 score was 53% (range 9.7?76.5%); the correlation between PIF stage and DIT score was ρ =  0.18 (p = 0.03). Students who took an analytic approach to the data and demonstrated both awareness that they are novices and anticipation of continued PIF tended to respond more positively to the feedback. These PIF scores distributed similarly to novice students in other professions. Developmental-theory based PIF and moral reasoning measures are related. Students reflected on these measures in meaningful ways suggesting utility of measuring PIF scores in medical education.

Formation of periodic surface structures on dielectrics after irradiation with laser beams of spatially variant polarisation: a comparative study

NASA Astrophysics Data System (ADS)

Papadopoulos, Antonis; Skoulas, Evangelos; Tsibidis, George D.; Stratakis, Emmanuel

2018-02-01

A comparative study is performed to explore the periodic structure formation upon intense femtosecond-pulsed irradiation of dielectrics with radially and azimuthally polarised beams. Laser conditions have been selected appropriately to produce excited carriers with densities below the optical breakdown threshold in order to highlight the role of phase transitions in surface modification mechanisms. The frequency of the laser-induced structures is calculated based on a theoretical model that comprises estimation of electron density excitation, heat transfer, relaxation processes, and hydrodynamics-related mass transport. The influence of the laser wavelength in the periodicity of the structures is also unveiled. The decreased energy absorption for azimuthally polarised beams yields periodic structures with smaller frequencies which are more pronounced as the number of laser pulses applied to the irradiation spot increases. Similar results are obtained for laser pulses of larger photon energy and higher fluences. All induced periodic structures are oriented parallel to the laser beam polarisation.

Early-Type Galaxy Star Formation Histories in Different Environments

NASA Astrophysics Data System (ADS)

Fitzpatrick, Patrick; Graves, G.

2014-01-01

We use very high-S/N stacked spectra of ˜29,000 nearby quiescent early-type galaxies (ETGs) from the Sloan Digital Sky Survey (SDSS) to investigate variations in their star formation histories (SFHs) with environment at fixed position along and perpendicular to the Fundamental Plane (FP). We separate galaxies in the three-dimensional FP space defined by galaxy effective radius Re, central stellar velocity dispersion σ, and surface brightness residual from the FP, ΔIe. We use the SDSS group catalogue of Yang et al. to further separate galaxies into three categories by their “identities” within their respective dark matter halos: central “Brightest Group Galaxies” (BGGs); Satellites; and Isolateds (those which are “most massive” in a dark matter halo with no Satellites). Within each category, we construct high-S/N mean stacked spectra to determine mean singleburst ages, [Fe/H], and [Mg/Fe] based on the stellar population synthesis models of R. Schiavon. This allows us to study variations in the stellar population properties (SPPs) with local group environment at fixed structure (i.e., fixed position in FP-space). We find that the SFHs of quiescent ETGs are almost entirely determined by their structural parameters σ and ΔIe. Any variation with local group environment at fixed structure is only slight: Satellites have the oldest stellar populations, 0.02 dex older than BGGs and 0.04 dex older than Isolateds; BGGs have the highest Fe-enrichments, 0.01 dex higher than Isolateds and 0.02 dex higher than Satellites; there are no differences in Mg-enhancement between BGGs, Isolateds, and Satellites. Our observation that, to zeroth-order, the SFHs of quiescent ETGs are fully captured by their structures places important qualitative constraints on the degree to which late-time evolutionary processes (those which occur after a galaxy’s initial formation and main star-forming lifetime) can alter their SFHs/structures.

The climatic, biotic and tectonic evolution of the Paleogene Renova formation of southwestern Montana

NASA Astrophysics Data System (ADS)

Lielke, Kevin John

The Renova Formation of southwestern Montana contains an important record of Paleogene floral, faunal, climate and tectonic change in the northern Rocky Mountains. The period between the end of the early Eocene and the early Oligocene (˜49--32 Ma) was a time of rapid and far-reaching climate change. This period saw the end of global greenhouse climate and the establishment of icehouse conditions across the Earth. These changes led to profound alterations in both marine and terrestrial ecosystems. This study examines the late Eocene/early Oligocene history of the northern Rocky Mountains by means of an integrated study of the sedimentology, tectonics and fossil content of the Renova Formation. The first part of this study examines plant fossils found in the Renova Formation in order to examine changes in the composition of the vegetation across the late Eocene/ early Oligocene (E/O) boundary. Plant remains are an effective proxy for climate and are used to estimate multiple climatic parameters across the E/O boundary. The second part of this study examines the paleotopography and paleodrainage patterns of the basins which accumulated the Renova sediments. This is accomplished by a combination of sedimentary facies and detrital zircon analysis. The third part of this study examines the tectonic underpinnings of Paleogene southwestern Montana through a combination of geologic field work and geodynamic modeling. The results of this study indicate that a seasonal summer dry climate became established in the northern Rocky Mountains by early Oligocene time. This is indicated by the elimination of subtropical plant species, the establishment of dry-adapted species and by paleoclimate parameters calculated from leaf physiognomy. Geodynamic calculations and field data indicate that the Renova Formation was deposited in a series of sub-basins separated by relict paleotopography and inverted topography formed by contemporary lava flows. Normal faulting was not active until

Elevated extracellular pH during early shell formation in the blue mussel Mytilus edulis

NASA Astrophysics Data System (ADS)

Ramesh, K.; Melzner, F.; Himmerkus, N.; Hu, M.; Bleich, M.

2016-02-01

Marine calcifiers are amongst the most vulnerable organisms to ocean acidification (OA). However, limited studies investigate the mechanisms underlying their hindered performance under OA stress. Working with larval stages of the blue mussel, Mytilus edulis, we use microsensors to study the pH and calcium conditions necessary for shell deposition. Using 45-48 hour, D-veliger stages, we discover alkaline conditions with respect to ambient seawater pH by 0.28 pH units and higher calcium concentrations (by 0.54mM) in the extra pallial space beneath the growing shell that likely promotes the rapid synthesis of the first shell. We further use enzyme assays in combination with immuno-stainings of sodium-potassium ATPase (NKA) and proton ATPase (VHA) to provide information on the major ion regulatory pathways that enable transport of calcium carbonate required for shell formation and pH homeostasis. We also use the juvenile stages of M. edulis to understand how extracellular pH regulation close to the shell formation site will be influenced by OA stress. This allows us to describe the pH dependency of early shell formation and to begin to develop a model of the ion regulatory network that facilitates biomineralisation in the organism. The results are discussed in the context of environmental change and consequences for mollusc developmental success.

Precambrian Time - The Story of the Early Earth

USGS Publications Warehouse

Lindsey, D.A.

2007-01-01

The Precambrian is the least-understood part of Earth history, yet it is arguably the most important. Precambrian time spans almost nine-tenths of Earth history, from the formation of the Earth to the dawn of the Cambrian Period. It represents time so vast and long ago that it challenges all comprehension. The Precambrian is the time of big questions. How old is the Earth? How old are the oldest rocks and continents? What was the early Earth like? What was the early atmosphere like? When did life appear, and what did it look like? And, how do we know this? In recent years, remarkable progress has been made in understanding the early evolution of the Earth and life itself. Yet, the scientific story of the early Earth is still a work in progress, humankind's latest attempt to understand the planet. Like previous attempts, it too will change as we learn more about the Earth. Read on to discover what we know now, in the early 21st century.

Periodic structure formation and surface morphology evolution of glassy carbon surfaces applying 35-fs-200-ps laser pulses

NASA Astrophysics Data System (ADS)

Csontos, J.; Toth, Z.; Pápa, Z.; Budai, J.; Kiss, B.; Börzsönyi, A.; Füle, M.

2016-06-01

In this work laser-induced periodic structures with lateral dimensions smaller than the central wavelength of the laser were studied on glassy carbon as a function of laser pulse duration. To generate diverse pulse durations titanium-sapphire (Ti:S) laser (center wavelength 800 nm, pulse durations: 35 fs-200 ps) and a dye-KrF excimer laser system (248 nm, pulse durations: 280 fs, 2.1 ps) were used. In the case of Ti:S laser treatment comparing the central part of the laser-treated areas a striking difference is observed between the femtoseconds and picoseconds treatments. Ripple structure generated with short pulse durations can be characterized with periodic length significantly smaller than the laser wavelength (between 120 and 165 nm). At higher pulse durations the structure has a higher periodic length (between 780 and 800 nm), which is comparable to the wavelength. In case of the excimer laser treatment the different pulse durations produced similar surface structures with different periodic length and different orientation. One of the structures was parallel with the polarization of the laser light and has a higher periodic length (~335 nm), and the other was perpendicular with smaller periodic length (~78-80 nm). The possible mechanisms of structure formation will be outlined and discussed in the frame of our experimental results.

The suppressive effect of immune stress on LH secretion is absent in the early neonatal period in rats.

PubMed

Munkhzaya, Munkhsaikhan; Matsuzaki, Toshiya; Iwasa, Takeshi; Tungalagsuvd, Altankhuu; Kawami, Takako; Kato, Takeshi; Kuwahara, Akira; Irahara, Minoru

2015-11-01

Some physiological functions display weak responses to stress in the early neonatal period; i.e., they exhibit stress hyporesponse periods. In this study, we evaluated whether gonadotropin regulatory factors exhibit stress hyporesponsive periods in male and female rats. Rats were intraperitoneally injected with lipopolysaccharide (100μg/kg) (LPS group) or saline (control group) on postnatal day (PND) 5, 10, 15, or 25. Then, their serum luteinizing hormone (LH) concentrations and hypothalamic mRNA levels of gonadotropin regulatory factors; i.e., kisspeptin (Kiss1), the kisspeptin receptor (Kiss1r), and gonadotropin-releasing hormone (GnRH), were measured at 2h after the injection. The hypothalamic mRNA levels of pro-inflammatory cytokines were also measured because they suppress gonadotropin secretion. The serum LH concentration of the LPS group was lower than that of the control group at PND25 in both sexes, but no such difference was seen at PND5, 10, or 15 in either sex. In both sexes, the hypothalamic tumor necrosis factor (TNF)α and interleukin (IL)-6 mRNA expression levels of the LPS group were higher than those of the control group at PND25, but not at PND5 or 10. The hypothalamic IL-1β mRNA expression level of the LPS group was higher than that of the control group at all time points. The hypothalamic Kiss1, Kiss1r, and GnRH mRNA expression levels of the LPS and control groups did not differ at any time point in either sex. These findings suggest that gonadotropin regulatory factors exhibit stress hyporesponse periods. The hypothalamic-pituitary-gonadal axis (HPG) might become responsive to immune stress between PND15 and 25, which could be related to enhanced hypothalamic cytokine expression. The avoidance of infectious stress during the early neonatal period might be important for normal development of the HPG axis. Copyright © 2015 Elsevier Ltd. All rights reserved.

The formation of sulfate and elemental sulfur aerosols under varying laboratory conditions: implications for early earth.

PubMed

DeWitt, H Langley; Hasenkopf, Christa A; Trainer, Melissa G; Farmer, Delphine K; Jimenez, Jose L; McKay, Christopher P; Toon, Owen B; Tolbert, Margaret A

2010-10-01

The presence of sulfur mass-independent fractionation (S-MIF) in sediments more than 2.45 × 10(9) years old is thought to be evidence for an early anoxic atmosphere. Photolysis of sulfur dioxide (SO(2)) by UV light with λ < 220 nm has been shown in models and some initial laboratory studies to create a S-MIF; however, sulfur must leave the atmosphere in at least two chemically different forms to preserve any S-MIF signature. Two commonly cited examples of chemically different sulfur species that could have exited the atmosphere are elemental sulfur (S(8)) and sulfuric acid (H(2)SO(4)) aerosols. Here, we use real-time aerosol mass spectrometry to directly detect the sulfur-containing aerosols formed when SO(2) either photolyzes at wavelengths from 115 to 400 nm, to simulate the UV solar spectrum, or interacts with high-energy electrons, to simulate lightning. We found that sulfur-containing aerosols form under all laboratory conditions. Further, the addition of a reducing gas, in our experiments hydrogen (H(2)) or methane (CH(4)), increased the formation of S(8). With UV photolysis, formation of S(8) aerosols is highly dependent on the initial SO(2) pressure; and S(8) is only formed at a 2% SO(2) mixing ratio and greater in the absence of a reductant, and at a 0.2% SO(2) mixing ratio and greater in the presence of 1000 ppmv CH(4). We also found that organosulfur compounds are formed from the photolysis of CH(4) and moderate amounts of SO(2). The implications for sulfur aerosols on early Earth are discussed. Key Words: S-MIF-Archean atmosphere-Early Earth-Sulfur aerosols.

Formation of the First Stars and Blackholes

NASA Astrophysics Data System (ADS)

Yoshida, Naoki

2018-05-01

Cosmic reionization is thought to be initiated by the first generation of stars and blackholes. We review recent progress in theoretical studies of early structure formation. Cosmic structure formation is driven by gravitational instability of primeval density fluctuations left over from Big Bang. At early epochs, there are baryonic streaming motions with significant relative velocity with respect to dark matter. The formation of primordial gas clouds is typically delayed by the streaming motions, but then physical conditions for the so-called direct collapse blackhole formation are realized in proto-galactic halos. We present a promising model in which intermediate mass blackholes are formed as early as z = 30.

An interesting new genus of Berothinae (Neuroptera: Berothidae) from the early Eocene Green River Formation, Colorado.

PubMed

Makarkin, Vladimir N

2017-01-30

Xenoberotha angustialata gen. et sp. nov. (Neuroptera: Berothidae) is described from the early Eocene of the Parachute Creek Member of the Green River Formation (U.S.A., Colorado). It is assigned to Berothinae as an oldest known member of the subfamily based on the presence of scale-like setae on the foreleg coxae. Distal crossveins of the fourth (outer) gradate series which are located very close to the wing margin in Xenoberotha gen. nov. is a character state previously unknown in Berothinae.

Worsened MRI findings during the early period of treatment with penicillin in a patient with general paresis.

PubMed

Zhang, She-Qing; Wan, Bo; Ma, Xiao-Long; Zheng, Hui-Min

2008-10-01

A 52-year-old man was diagnosed with general paresis, whose HIV antibodies were negative. After initiation of treatment with penicillin on the first day, no obvious clinical Jarisch-Herxheimer reaction was found. However, 6 days after treatment, the patient was found more irritable and was unable to fall asleep at night. On the seventh day, worsened magnetic resonance imaging (MRI) abnormalities in the bilateral medial and anterior temporal lobes were unexpectedly discovered. These worsened MRI abnormalities improved quickly after the addition of dexamethasone treatment. We consider that these transient and slight mental symptoms may be associated with the transiently worsening phenomenon in cerebral MRI findings during the early period of treatment with penicillin. This indicates that some nonspecific inflammatory process has happened in the early stage of treatment, which necessitates the use of corticosteroids after the occurrence of systemic or mental symptoms.

Early Detection | Division of Cancer Prevention

Cancer.gov

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Influence of pre- or intraoperational use of tramadol (preemptive or preventive analgesia) on tramadol requirement in the early postoperative period.

PubMed

Wordliczek, Jerzy; Banach, Marcin; Garlicki, Jarosław; Jakowicka-Wordliczek, Joanna; Dobrogowski, Jan

2002-01-01

The aim of this study was to assess the influence of iv tramadol on opioid requirement in the early postoperative period. The subjects were 90 patients scheduled for colon surgery (hemicolectomy) who received general anesthesia using the (N2O/O2) isoflurane technique. Thirty patients (group I) were administered 100 mg of tramadol iv before induction of general anesthesia (preemptive analgesia). Group II (30 patients) was administered 100 mg of tramadol iv immediately after peritoneal closure (preventive analgesia) and control group (30 patients) received 100 mg of tramadol iv immediately after operation. Following the operation, all patients were administered tramadol in the PCA-iv mode in order to treat postoperative pain. In the postoperative period, the following parameters were measured: pain intensity (using VAS), total consumption of tramadol, time until the first PCA activation, and frequency of side effects (drowsiness, nausea, vomiting). In patients of groups I and II who had received preemptive or preventive analgesia, a significantly lower total consumption of tramadol, as compared with control group, was observed in the early postoperative period. However, the time until the first PCA activation was significantly shorter in group I as compared to the other two groups. No significant differences between the groups were found regarding pain intensity and frequency of side effects.

Monkey primary somatosensory cortical activity during the early reaction time period differs with cues that guide movements

PubMed Central

Liu, Yu; Denton, John M.; Nelson, Randall J.

2009-01-01

Vibration-related neurons in monkey primary somatosensory cortex (SI) discharge rhythmically when vibratory stimuli are presented. It remains unclear how functional information carried by vibratory inputs is coded in rhythmic neuronal activity. In the present study, we compared neuronal activity during wrist movements in response to two sets of cues. In the first, movements were guided by vibratory cue only (VIB trials). In the second, movements were guided by simultaneous presentation of both vibratory and visual cues (COM trials). SI neurons were recorded extracellularly during both wrist extensions and flexions. Neuronal activity during the instructed delay period (IDP) and the early reaction time period (RTP) were analyzed. A total of 96 cases from 48 neurons (each neuron contributed two cases, one each for extension and flexion) showed significant vibration entrainment during the early RTPs, as determined by circular statistics (Rayleigh test). Of these, 50 cases had cutaneous (CUTA) and 46 had deep (DEEP) receptive fields. The CUTA neurons showed lower firing rates during the IDPs and greater firing rate changes during the early RTPs when compared with the DEEP neurons. The CUTA neurons also demonstrated decreases in activity entrainment during VIB trials when compared with COM trials. For the DEEP neurons, the difference of entrainment between VIB and COM trials was not statistically significant. The results suggest that somatic vibratory input is coded by both the firing rate and the activity entrainment of the CUTA neurons in SI. The results also suggest that when vibratory inputs are required for successful task completion, the activity of the CUTA neurons increases but the entrainment degrades. The DEEP neurons may be tuned before movement initiation for processing information encoded by proprioceptive afferents. PMID:18288475

Dynamics of the formation of laser-induced periodic surface structures (LIPSS) upon femtosecond two-color double-pulse irradiation of metals, semiconductors, and dielectrics

NASA Astrophysics Data System (ADS)

Höhm, S.; Herzlieb, M.; Rosenfeld, A.; Krüger, J.; Bonse, J.

2016-06-01

In order to address the dynamics and physical mechanisms of LIPSS formation for three different classes of materials (metals, semiconductors, and dielectrics), two-color double-fs-pulse experiments were performed on Titanium, Silicon and Fused Silica. For that purpose a Mach-Zehnder interferometer generated polarization controlled (parallel or cross-polarized) double-pulse sequences at 400 nm and 800 nm wavelength, with inter-pulse delays up to a few picoseconds. Multiple of these two-color double-pulse sequences were collinearly focused by a spherical mirror to the sample surfaces. The fluence of each individual pulse (400 nm and 800 nm) was always kept below its respective ablation threshold and only the joint action of both pulses lead to the formation of LIPSS. Their resulting characteristics (periods, areas) were analyzed by scanning electron microscopy. The periods along with the LIPSS orientation allow a clear identification of the pulse which dominates the energy coupling to the material. For strong absorbing materials (Silicon, Titanium), a wavelength-dependent plasmonic mechanism can explain the delay-dependence of the LIPSS. In contrast, for dielectrics (Fused Silica) the first pulse always dominates the energy deposition and LIPSS orientation, supporting a non-plasmonic formation scenario. For all materials, these two-color experiments confirm the importance of the ultrafast energy deposition stage for LIPSS formation.

Formation of the Lunar Fossil Bulges and its Implication for the Early Earth and Moon

NASA Astrophysics Data System (ADS)

Qin, C.; Zhong, S.; Phillips, R. J.

2017-12-01

First recognized by Laplace more than two centuries ago, the lunar gravitational and shape anomalies associated with rotational and tidal bulges are significantly larger than predicted from the hydrostatic theory. The harmonic degree-2 gravitational coefficients of the Moon, C20 and C22 (measuring the size of the rotational and tidal bulges), are 17 and 14 times of their hydrostatic counterparts, respectively, after removal of the effect from large impact basins. The bulges are commonly considered as remnant hydrostatic features, "frozen-in" when the Moon was closer to the Earth, experiencing larger tidal-rotational forces. The extant hypothesis is that as the Moon cooled and migrated outwards, a strong outer layer (lithosphere) thickened and reached a stress state that supported the bulges, which no longer tracked the hydrostatic ellipticity. However, this process is poorly understood and an appropriate dynamical model has not been engaged. Here we present the first dynamically self-consistent model of lunar bulge formation that couples a lunar interior thermal evolution model to the tidal-rotational forcing of the Moon. The forcing magnitude decreases with time as the Moon despins on the receding orbit, while the recession rate is controlled by the Earth's tidal dissipation factor Q. Assuming a viscoelastic rheology, the cooling of the Moon is described by a model with high viscosity lithosphere thickening with time. While conventional methods are not suitable for models with time-dependent viscoelastic structure, a semi-analytical method has been developed to address this problem. We show that the bulge formation is controlled by the relative timing of lithosphere thickening and lunar orbit recession. Based on our calculations, we conclude that the development of the fossil bulges may have taken as long as 400 million years after the formation of lunar lithosphere and was complete when the lunar orbit semi-major axis, a, was 32 Earth's radius, RE. We find a

Pedo-sedimentary record of human-environment interaction in ditches and waterlogged depressions on tableland (roman and early medieval period) : micromorphological cases studies from Marne-la-Vallée area (Paris Basin, France)

NASA Astrophysics Data System (ADS)

Cammas, C.; Blanchard, J.; Broutin, P.; Berga, A.

2012-04-01

On lœss derived soils located on the Stampien plateau from the Paris Basin (France), archaeological anthroposols and ancient cultivated soils are only preserved in very few places. Recent archaeological excavations showed the presence of a pattern of roman ditches and waterlogged depressions (« mares ») under the actual cultivated horizon (Ap). This presence strongly suggests extensive past agricultural practices and water management. An original system of ditches was found Near Marne-la-Vallée (France). It is composed of two parts, one being large ditches characterized by flat bottom and sometimes water layered deposits, called « fossés collecteurs » by the archaeologists, and the orher being smaller ditches with colluvial deposits. Our objectives was to use archaeological and micromorphological studies in order to study i) the agricultural function of these ditches and depressions, ii) their evolution with time. Observations conducted on the infilling of a « fossé collecteur » at Bussy-Saint-Georges suggest that it was not part of a drainage system, but that it was a linear water controlled system, with a ramp in one part, and a basin or a tank in another, and that it was used for others anthropic activities. In the same area, a large waterlogged depression was studied, and micromorphological analysis helped to elucidate its pedo-sedimentary formation processes. At the bottom, massive silty clayey matrix retained water. Thin layers composed of silt and clay (indicating low energy flows and decantation), sometimes impregnated and hardened by iron, alternated with silty deposit (indicating higher ernergy water layered deposits). The thin, non porous and iron impregnated crusts helped to raise the depression level, as well as, most likely the water table during roman period, maintaining waterlogging conditions. At the beginning of the early medival period, a slightly peaty event was discriminated. Higher in the profile, in more redoxic conditions

Medicinal exploitation of inorganic substances in the Levant in the Medieval and early Ottoman periods.

PubMed

Lev, Efraim

2002-11-01

Various minerals, metals, clays, and rocks were among the natural medicinal substances used by physicians and pharmacists in early times in different cultures, for example, the ancient civilizations of Egypt and Mesopotamia. Classical physicians such as Hippocrates and Dioscorides mention tens of inorganic medicinal substances in their writings. Many references to minerals and chemicals are also found in the Muslim medical literature of the Eastern and Western Caliphates. The historical research presented in this article focuses on the inorganic substances applied as remedies by the medieval and early Ottoman (7th-17th) inhabitants of the Levant. The article is based upon a literature review covering tens of different historical sources, from the medieval and early Ottoman periods. Relevant information was found in the works of physicians such as al-Tamimi, Benevenutus, Ibn al-Baytar, Daud al-Antaki, and Hayyim Vital. The research revealed evidences of the medicinal uses of fifteen inorganic substances: Alum, Arsenic, Sulphide, Asphalt, Jew's stone, Earth sp., Galena, Haematite, iron, Lead, Pyrite, Salt, Sulphur, Thermal water, Green Vitriol, and Zinc. Inorganic materials comprise 5.2% of the list of medicinal substances. The geographic origin of most of these substances is the Levant, in which two geo-historical centers have been recorded: the Rift Valley and the northern region of the Levant, including upper Galilee, Mount Lebanon and Mount Hermon. A notable tendency to use these substances for treating diseases of the skin, the eyes, the sexual organs, and haemorrhoids was detected.

Late Noachian and early Hesperian ridge systems in the south circumpolar Dorsa Argentea Formation, Mars: Evidence for two stages of melting of an extensive late Noachian ice sheet

NASA Astrophysics Data System (ADS)

Kress, Ailish M.; Head, James W.

2015-05-01

The Dorsa Argentea Formation (DAF), extending from 270°-100° E and 70°-90° S, is a huge circumpolar deposit surrounding and underlying the Late Amazonian South Polar Layered Deposits (SPLD) of Mars. Currently mapped as Early-Late Hesperian in age, the Dorsa Argentea Formation has been interpreted as volatile-rich, possibly representing the remnants of an ancient polar ice cap. Uncertain are its age (due to the possibility of poor crater retention in ice-related deposits), its mode of origin, the origin of the distinctive sinuous ridges and cavi that characterize the unit, and its significance in the climate history of Mars. In order to assess the age of activity associated with the DAF, we examined the ridge populations within the Dorsa Argentea Formation, mapping and characterizing seven different ridge systems (composed of nearly 4,000 ridges covering a total area of ~300,000 km2, with a cumulative length of ridges of ~51,000 km) and performing crater counts on them using the method of buffered crater counting to determine crater retention ages of the ridge populations. We examined the major characteristics of the ridge systems and found that the majority of them were consistent with an origin as eskers, sediment-filled subglacial drainage channels. Ridge morphologies reflect both distributed and channelized esker systems, and evidence is also seen that some ridges form looping moraine-like termini distal to some distributed systems. The ridge populations fall into two age groups: ridge systems between 270° and 0° E date to the Early Hesperian, but to the east, the Promethei Planum and the Chasmata ridge systems date to the Late Noachian. Thus, these ages, and esker and moraine-like morphologies, support the interpretation that the DAF is a remnant ice sheet deposit, and that the esker systems represent evidence of significant melting and drainage of meltwater from portions of this ice sheet, thus indicating at least some regions and/or periods of wet

Cutting-Balloon Angioplasty in Transplant Renal Artery Stenosis as First-Line Treatment in the Early Postoperative Period

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ucar, Adem, E-mail: ucaradem@yahoo.com; Yahyayev, Aghakishi, E-mail: aghakishi@yahoo.com; Bakkaloglu, Huseyin, E-mail: drhuseyin@yahoo.com

2011-02-15

Percutaneous transluminal angioplasty has been successfully used for the treatment of transplant renal artery stenosis (RAS). Cutting-balloon angioplasty (CBA) is being used as a second option in pressure-resistant stenosis. It is thought that CBA is less traumatic and therefore restenosis occurs less frequently than in conventional angioplasty. This case report describes the unusual use of a cutting balloon in transplant RAS as a first option in the early postoperative period. Long-term follow-up data are also presented.

A SoxC gene related to larval shell development and co-expression analysis of different shell formation genes in early larvae of oyster.

PubMed

Liu, Gang; Huan, Pin; Liu, Baozhong

2017-06-01

Among the potential larval shell formation genes in mollusks, most are expressed in cells surrounding the shell field during the early phase of shell formation. The only exception (cgi-tyr1) is expressed in the whole larval mantle and thus represents a novel type of expression pattern. This study reports another gene with such an expression pattern. The gene encoded a SoxC homolog of the Pacific oyster Crassostrea gigas and was named cgi-soxc. Whole-mount in situ hybridization revealed that the gene was highly expressed in the whole larval mantle of early larvae. Based on its spatiotemporal expression, cgi-soxc is hypothesized to be involved in periostracum biogenesis, biomineralization, and regulation of cell proliferation. Furthermore, we investigated the interrelationship between cgi-soxc expression and two additional potential shell formation genes, cgi-tyr1 and cgi-gata2/3. The results confirmed co-expression of the three genes in the larval mantle of early D-veliger. Nevertheless, cgi-gata2/3 was only expressed in the mantle edge, and the other two genes were expressed in all mantle cells. Based on the spatial expression patterns of the three genes, two cell groups were identified from the larval mantle (tyr1 + /soxc + /gata2/3 + cells and tyr1 + /soxc + /gata2/3 - cells) and are important to study the differentiation and function of this tissue. The results of this study enrich our knowledge on the structure and function of larval mantle and provide important information to understand the molecular mechanisms of larval shell formation.

Laser-induced periodic surface structures formation on mesoporous silicon from nanoparticles produced by picosecond and femtosecond laser shots

NASA Astrophysics Data System (ADS)

Talbi, Abderazek; Kaya-Boussougou, Sostaine; Sauldubois, Audrey; Stolz, Arnaud; Boulmer-Leborgne, Chantal; Semmar, Nadjib

2017-07-01

This paper deals with the formation of laser-induced periodic surface structures (LIPSS) on mesoporous silicon thin films induced by two laser regimes in the UV range: picosecond and femtosecond. Different LIPSS formation mechanisms from nanoparticles, mainly coalescence and agglomeration, have been evidenced by scanning electron microscopy analysis. The apparition of a liquid phase during both laser interaction at low fluence (20 mJ/cm2) and after a large number of laser pulses (up to 12,000) has been also shown with 100 nm size through incubation effect. Transmission electron microscopy analyses have been conducted to investigate the molten phase structures below and inside LIPSS. Finally, it has shown that LIPSS are composed of amorphous silicon when mesoporous silicon is irradiated by laser beam in both regimes. Nevertheless, mesoporous silicon located between LIPSS stays crystallized.

Green Peas emit X-rays: Extreme Star Formation in Early Universe Analog Galaxies

NASA Astrophysics Data System (ADS)

Brorby, Matthew; Kaaret, Philip

2017-01-01

Luminous compact galaxies (LCGs), Lyman Alpha Emitters (LAEs), and Lyman Break Analog galaxies (LBAs) are all used as proxies for star-forming galaxies in the early Universe (z ≥ 6). The X-ray emission from such galaxies has been found to be elevated compared to other star-forming galaxies in our local Universe. It has been suggested that this may be due to the lower metallicity seen in these proxies to high-redshift galaxies and the elevated X-ray emission may affect the heating and Reionization evolution of the early Universe. Our previous studies have suggested the existence of an LX-SFR-metallicity plane for all star-forming galaxies. We present these results in the context of our newest Joint Chandra/HST study containing the first X-ray detection of the Green Pea galaxies, a population of compact starburst galaxies discovered by volunteers in the Galaxy Zoo Project (Cardamone+2009). The galaxies were given the name Green Peas due to their compact size and green appearance in the gri composite images from SDSS. The green color is caused by a strong [OIII]λ5007Å emission line, an indicator of recent star formation. We observed a few of the most promising candidates with joint Chandra/HST observation and discuss our findings here.

Long-orbital-period Prepolars Containing Early K-type Donor Stars. Bottleneck Accretion Mechanism in Action

NASA Astrophysics Data System (ADS)

Tovmassian, G.; González–Buitrago, D.; Zharikov, S.; Reichart, D. E.; Haislip, J. B.; Ivarsen, K. M.; LaCluyze, A. P.; Moore, J. P.; Miroshnichenko, A. S.

2016-03-01

We studied two objects identified as cataclysmic variables (CVs) with periods exceeding the natural boundary for Roche-lobe-filling zero-age main sequence (ZAMS) secondary stars. We present observational results for V1082 Sgr with a 20.82 hr orbital period, an object that shows a low luminosity state when its flux is totally dominated by a chromospherically active K star with no signs of ongoing accretion. Frequent accretion shutoffs, together with characteristics of emission lines in a high state, indicate that this binary system is probably detached, and the accretion of matter on the magnetic white dwarf takes place through stellar wind from the active donor star via coupled magnetic fields. Its observational characteristics are surprisingly similar to V479 And, a 14.5 hr binary system. They both have early K-type stars as donor stars. We argue that, similar to the shorter-period prepolars containing M dwarfs, these are detached binaries with strong magnetic components. Their magnetic fields are coupled, allowing enhanced stellar wind from the K star to be captured and channeled through the bottleneck connecting the two stars onto the white dwarf’s magnetic pole, mimicking a magnetic CV. Hence, they become interactive binaries before they reach contact. This will help to explain an unexpected lack of systems possessing white dwarfs with strong magnetic fields among detached white+red dwarf systems.

A model of early formation of uranium molecular oxides in laser-ablated plasmas

NASA Astrophysics Data System (ADS)

Finko, Mikhail; Curreli, Davide; Azer, Magdi; Weisz, David; Crowhurst, Jonathan; Rose, Timothy; Koroglu, Batikan; Radousky, Harry; Zaug, Joseph; Armstrong, Mike

2017-10-01

An important problem within the field of nuclear forensics is fractionation: the formation of post-detonation nuclear debris whose composition does not reflect that of the source weapon. We are investigating uranium fractionation in rapidly cooling plasma using a combined experimental and modeling approach. In particular, we use laser ablation of uranium metal samples to produce a low-temperature plasma with physical conditions similar to a condensing nuclear fireball. Here we present a first plasma-chemistry model of uranium molecular species formation during the early stage of laser ablated plasma evolution in atmospheric oxygen. The system is simulated using a global kinetic model with rate coefficients calculated according to literature data and the application of reaction rate theory. The model allows for a detailed analysis of the evolution of key uranium molecular species and represents the first step in producing a uranium fireball model that is kinetically validated against spatially and temporally resolved spectroscopy measurements. This project was sponsored by the DoD, Defense Threat Reduction Agency, Grant HDTRA1-16- 1-0020. This work was performed in part under the auspices of the U.S. DoE by Lawrence Livermore National Laboratory under Contract DE-AC52- 07NA27344.

The 2013 Frank Stinchfield Award: Diagnosis of infection in the early postoperative period after total hip arthroplasty.

PubMed

Yi, Paul H; Cross, Michael B; Moric, Mario; Sporer, Scott M; Berger, Richard A; Della Valle, Craig J

2014-02-01

Diagnosis of periprosthetic joint infection (PJI) can be difficult in the early postoperative period after total hip arthroplasty (THA) because normal cues from the physical examination often are unreliable, and serological markers commonly used for diagnosis are elevated from the recent surgery. The purposes of this study were to determine the optimal cutoff values for erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), synovial fluid white blood cell (WBC) count, and differential for diagnosing PJI in the early postoperative period after primary THA. We reviewed 6033 consecutive primary THAs and identified 73 patients (1.2%) who underwent reoperation for any reason within the first 6 weeks postoperatively. Thirty-six of these patients were infected according to modified Musculoskeletal Infection Society criteria. Mean values for the diagnostic tests were compared between groups and receiver operating characteristic curves generated along with an area under the curve (AUC) to determine test performance and optimal cutoff values to diagnose infection. The best test for the diagnosis of PJI was the synovial fluid WBC count (AUC = 98%; optimal cutoff value 12,800 cells/μL) followed by the CRP (AUC = 93%; optimal cutoff value 93 mg/L), and synovial fluid differential (AUC = 91%; optimal cutoff value 89% PMN). The mean ESR (infected = 69 mm/hr, not infected = 46 mm/hr), CRP (infected = 192 mg/L, not infected = 30 mg/L), synovial fluid WBC count (infected = 84,954 cells/μL, not infected = 2391 cells/μL), and differential (infected = 91% polymorphonuclear cells [PMN], not infected = 63% PMN) all were significantly higher in the infected group. Optimal cutoff values for the diagnosis of PJI in the acute postoperative period were higher than those traditionally used for the diagnosis of chronic PJI. The serum CRP is an excellent screening test, whereas the synovial fluid WBC count is more specific.

Adolescent Violent Victimization and Precocious Union Formation.

PubMed

C Kuhl, Danielle; Warner, David F; Wilczak, Andrew

2012-11-01

This article bridges scholarship in criminology and family sociology by extending arguments about "precocious exits" from adolescence to consider early union formation as a salient outcome of violent victimization for youths. Research indicates that early union formation is associated with several negative outcomes; yet the absence of attention to union formation as a consequence of violent victimization is noteworthy. We address this gap by drawing on life course theory and data from the National Longitudinal Study of Adolescent Health (Add Health) to examine the effect of violent victimization ("street" violence) on the timing of first co-residential union formation-differentiating between marriage and cohabitation-in young adulthood. Estimates from Cox proportional hazard models show that adolescent victims of street violence experience higher rates of first union formation, especially marriage, early in the transition to adulthood; however, this effect declines with age, as such unions become more normative. Importantly, the effect of violent victimization on first union timing is robust to controls for nonviolent delinquency, substance abuse, and violent perpetration. We conclude by discussing directions for future research on the association between violent victimization and coresidential unions with an eye toward the implications of such early union formation for desistance.

The MACHO Project LMC Variable Star Inventory. VIII. The Recent Star Formation History of the Large Magellanic Cloud from the Cepheid Period Distribution

NASA Astrophysics Data System (ADS)

Alcock, C.; Allsman, R. A.; Alves, D. R.; Axelrod, T. S.; Becker, A. C.; Bennett, D. P.; Bersier, D. F.; Cook, K. H.; Freeman, K. C.; Griest, K.; Guern, J. A.; Lehner, M.; Marshall, S. L.; Minniti, D.; Peterson, B. A.; Pratt, M. R.; Quinn, P. J.; Rodgers, A. W.; Stubbs, C. W.; Sutherland, W.; Tomaney, A.; Vandehei, T.; Welch, D. L.

1999-02-01

We present an analysis of the period distribution of about 1800 Cepheids in the LMC, based on data obtained by the MACHO microlensing experiment and on a previous catalog by C. H. Payne Gaposchkin. Using stellar evolution and pulsation models, we construct theoretical period-frequency distributions that are compared with the observations. These models reveal that a significant burst of star formation has occurred recently in the LMC (~1.15x10^8 yr). We also show that during the last ~10^8 yr, the main center of star formation has been propagating from southeast to northwest along the bar. We find that the evolutionary masses of Cepheids are still smaller than pulsation masses by ~7% and that the red edge of the Cepheid instability strip could be slightly bluer than indicated by theory. There are approximately 600 Cepheids with periods below ~2.5 days that cannot be explained by evolution theory. We suggest that they are anomalous Cepheids and that a number of these stars are double-mode Cepheids.

Formation of a periodic diffractive structure based on poly(methyl methacrylate) with ion-implanted silver nanoparticles

NASA Astrophysics Data System (ADS)

Galyautdinov, M. F.; Nuzhdin, V. I.; Fattakhov, Ya. V.; Farrakhov, B. F.; Valeev, V. F.; Osin, Yu. N.; Stepanov, A. L.

2016-02-01

We propose to form optical diffractive elements on the surface of poly(methyl methacrylate) (PMMA) by implanting the polymer with silver ions ( E = 30 keV; D = 5.0 × 1014 to 1.5 × 1017 ion/cm2; I = 2 μA/cm2) through a nickel grid (mask). Ion implantation leads to the nucleation and growth of silver nanoparticles in unmasked regions of the polymer. The formation of periodic surface microstructures during local sputtering of the polymer by incident ions was monitored using an optical microscope. The diffraction efficiency of obtained gratings is demonstrated under conditions of their probing with semiconductor laser radiation in the visible spectral range.

Rethinking early Earth phosphorus geochemistry

PubMed Central

Pasek, Matthew A.

2008-01-01

Phosphorus is a key biologic element, and a prebiotic pathway leading to its incorporation into biomolecules has been difficult to ascertain. Most potentially prebiotic phosphorylation reactions have relied on orthophosphate as the source of phosphorus. It is suggested here that the geochemistry of phosphorus on the early Earth was instead controlled by reduced oxidation state phosphorus compounds such as phosphite (HPO32−), which are more soluble and reactive than orthophosphates. This reduced oxidation state phosphorus originated from extraterrestrial material that fell during the heavy bombardment period or was produced during impacts, and persisted in the mildly reducing atmosphere. This alternate view of early Earth phosphorus geochemistry provides an unexplored route to the formation of pertinent prebiotic phosphorus compounds, suggests a facile reaction pathway to condensed phosphates, and is consistent with the biochemical usage of reduced oxidation state phosphorus compounds in life today. Possible studies are suggested that may detect reduced oxidation state phosphorus compounds in ancient Archean rocks. PMID:18195373

Rethinking early Earth phosphorus geochemistry.

PubMed

Pasek, Matthew A

2008-01-22

Phosphorus is a key biologic element, and a prebiotic pathway leading to its incorporation into biomolecules has been difficult to ascertain. Most potentially prebiotic phosphorylation reactions have relied on orthophosphate as the source of phosphorus. It is suggested here that the geochemistry of phosphorus on the early Earth was instead controlled by reduced oxidation state phosphorus compounds such as phosphite (HPO(3)(2-)), which are more soluble and reactive than orthophosphates. This reduced oxidation state phosphorus originated from extraterrestrial material that fell during the heavy bombardment period or was produced during impacts, and persisted in the mildly reducing atmosphere. This alternate view of early Earth phosphorus geochemistry provides an unexplored route to the formation of pertinent prebiotic phosphorus compounds, suggests a facile reaction pathway to condensed phosphates, and is consistent with the biochemical usage of reduced oxidation state phosphorus compounds in life today. Possible studies are suggested that may detect reduced oxidation state phosphorus compounds in ancient Archean rocks.

Timing the formation and assembly of early-type galaxies via spatially resolved stellar populations analysis

NASA Astrophysics Data System (ADS)

Martín-Navarro, Ignacio; Vazdekis, Alexandre; Falcón-Barroso, Jesús; La Barbera, Francesco; Yıldırım, Akın; van de Ven, Glenn

2018-04-01

To investigate star formation and assembly processes of massive galaxies, we present here a spatially resolved stellar population analysis of a sample of 45 elliptical galaxies (Es) selected from the Calar Alto Legacy Integral Field Area survey. We find rather flat age and [Mg/Fe] radial gradients, weakly dependent on the effective velocity dispersion of the galaxy within half-light radius. However, our analysis shows that metallicity gradients become steeper with increasing galaxy velocity dispersion. In addition, we have homogeneously compared the stellar population gradients of our sample of Es to a sample of nearby relic galaxies, i.e. local remnants of the high-z population of red nuggets. This comparison indicates that, first, the cores of present-day massive galaxies were likely formed in gas-rich, rapid star formation events at high redshift (z ≳ 2). This led to radial metallicity variations steeper than observed in the local Universe, and positive [Mg/Fe] gradients. Secondly, our analysis also suggests that a later sequence of minor dry mergers, populating the outskirts of early-type galaxies (ETGs), flattened the pristine [Mg/Fe] and metallicity gradients. Finally, we find a tight age-[Mg/Fe] relation, supporting that the duration of the star formation is the main driver of the [Mg/Fe] enhancement in massive ETGs. However, the star formation time-scale alone is not able to fully explain our [Mg/Fe] measurements. Interestingly, our results match the expected effect that a variable stellar initial mass function would have on the [Mg/Fe] ratio.

Confusion in the Periodic Table of the Elements.

ERIC Educational Resources Information Center

Fernelius, W. C.; Powell, W. H.

1982-01-01

Discusses long (expanded), short (condensed), and pyramidal periodic table formats and documents events leading to a periodic table in which subgroups (families) are designated with the letters A and B, suggesting that this format is confusing for those consulting the table. (JN)

New particle formation at ground level and in the vertical column over the Barcelona area

NASA Astrophysics Data System (ADS)

Minguillón, M. C.; Brines, M.; Pérez, N.; Reche, C.; Pandolfi, M.; Fonseca, A. S.; Amato, F.; Alastuey, A.; Lyasota, A.; Codina, B.; Lee, H.-K.; Eun, H.-R.; Ahn, K.-H.; Querol, X.

2015-10-01

The vertical profiles (up to 975 m a.s.l.) of ultrafine and micronic particles across the planetary boundary layer and the free troposphere over a Mediterranean urban environment were investigated. Measurements were carried out using a tethered balloon equipped with a miniaturized condensation particle counter, a miniaturized optical particle counter, a micro-aethalometer, a rotating impactor, and meteorological instrumentation. Simultaneous ground measurements were carried out at an urban and a regional background site. New particle formation episodes initiating in the urban area were observed under high insolation conditions. The precursors were emitted by the city and urban photochemically-activated nucleation occurred both at high atmospheric levels (tens to hundreds of meters) and at ground level. The new particle formation at ground level was limited by the high particulate matter concentrations recorded during the morning traffic rush hours that increase the condensation sink and prevent new particle formation, and therefore restricted to midday and early afternoon. The aloft new particle formation occurred earlier as the thermally ascending polluted air mass was diluted. The regional background was only affected from midday and early afternoon when sea and mountain breezes transported the urban air mass after particle growth. These events are different from most new particle formation events described in literature, characterized by a regionally originated nucleation, starting early in the morning in the regional background and persisting with a subsequent growth during a long period. An idealized and simplified model of the spatial and time occurrence of these two types of new particle formation episodes into, around and over the city was elaborated.

Early formation of dental plaque on platic films. 1. Light microscopic observations.

PubMed

Rönström, A; Attström, R; Egelberg, J

1975-02-01

In human subjects with healthy gingiva thin transparent plastic films were applied to the buccal surfaces of premolars in the upper and lower jaws. The films were left in place for peiods of 15, 30, 60, 120 and 240 minutes. The presence of coccoid bacteria, leukocytes and epithelial cells was investigated in an area adjacent to the gingival margin. The results showed that by 15 minutes coccoid bacteria had become attached to the artificial tooth surface. The number of microorganisms gradually increased during the time of the study. Large numbers of cocci and the formation of micro-colonies were observed after 120 and 240 minutes. Increasing numbers of leukocytes and epithelial cells were also found during the period of observation.

Effect of fast pH decline during the early postmortem period on calpain activity and cytoskeletal protein degradation of broiler M. pectoralis major.

PubMed

Huang, J C; Yang, J; Huang, F; Huang, M; Chen, K J; Xu, X L; Zhou, G H

2016-10-01

The objective of this study was to determine the effects of fast pH decline during the early postmortem period on calpain activity and the degradation of cytoskeletal proteins in broilers. Eighty broilers were randomly categorized into two groups: physical restraint (PR) and free struggle (FS). M. pectoralis major (PM) was used for determination of calpain activity, shear value, ultrastructure of myofibrils, and the degradation of desmin, titin, nebulin, and troponin-T. The pH (6.05) of FS group is significantly low than PR group (6.38) at 0.3 h postmortem. Fast pH decline during the early postmortem period led to a decrease of μ/m-calpain activities at 0.3 and 3 h postmortem (P < 0.05), but did not affect the ultimate μ/m-calpain activity. An initial fast decrease in pH increased the degradation of desmin, titin, nebulin, and increased the 30 kDa degradation fragments of troponin-T. Therefore, the fast pH decline during the early postmortem period decreased the μ/m-calpain activity and increased the degradation of cytoskeletal proteins in broiler muscle. It is possible that the fast pH decline experienced an earlier activation of calpains that resulted in earlier protein degradation and ultimately lower shear force. © 2016 Poultry Science Association Inc.

[Analysis of the incidence and causes of repeated surgical interventions in patients with early complications electrotherapy - 1 center experience from the period 2012-2015].

PubMed

Piątek, Łukasz; Polewczyk, Anna; Kurzawski, Jacek; Zachura, Małgorzata; Kaczmarczyk, Małgorzata; Janion, Marianna

Due to increasing number of patients treated by cardiac implantable electronic devices we observe increasing number of complications after these procedures We analysed causes of early surgical revision of implantable devices connected with 1673 procedures of implantation (871 procedures) or exchange (802 procedures) of pacing systems (PM), cardioverter-difibrillators (ICD) and resynchronisation systems (CRT) in one local centre of electrotherapy in years 2012 to 2015. We characterised risk factors and its influence on encountered complications. In analysed period 72 reinterventions after implantations or exchanges of PM/ICD/CRT were performed. Main causes of early complications were: lead malfunction (2.5%), including the dislodgement of the leads in 1.9%, pocket hematoma (1.4%) and other abnormalities of the pocket (0.4 %), including pocket infections in 0.2%. The most important risk factors of early complications were often implantations of the leads with passive fixation and anticoagulation therapy in perioperative period. The knowledge of the early complications after implantations and exchanges of PM/ICD/CRT should improve the safety of procedures through more often used of the leads with active fixation and properly preparation of the patients requering the antithrombic therapy.

A Formative Study Investigating the Acquisition of Early Reading Skills among High School English Language Learners Beginning to Read English

ERIC Educational Resources Information Center

Bell, Athene Cooper

2012-01-01

A formative design experiment methodology was employed to investigate the acquisition of early reading skills for high school English language learners (ELLs) beginning to read English. A fundamental challenge facing high school ELLs entering schools in the United States for the first time is learning how to read. While there is considerable…

Early mechanical stimulation only permits timely bone healing in sheep.

PubMed

Tufekci, Pelin; Tavakoli, Aramesh; Dlaska, Constantin; Neumann, Mirjam; Shanker, Mihir; Saifzadeh, Siamak; Steck, Roland; Schuetz, Michael; Epari, Devakar

2018-06-01

Bone fracture healing is sensitive to the fixation stability. However, it is unclear which phases of healing are mechano-sensitive and if mechanical stimulation is required throughout repair. In this study, a novel bone defect model, which isolates an experimental fracture from functional loading, was applied in sheep to investigate if stimulation limited to the early proliferative phase is sufficient for bone healing. An active fixator controlled motion in the fracture. Animals of the control group were unstimulated. In the physiological-like group, 1 mm axial compressive movements were applied between day 5 and 21, thereafter the movements were decreased in weekly increments and stopped after 6 weeks. In the early stimulatory group, the movements were stopped after 3 weeks. The experimental fractures were evaluated with mechanical and micro-computed tomography methods after 9 weeks healing. The callus strength of the stimulated fractures (physiological-like and early stimulatory) was greater than the unstimulated control group. The control group was characterized by minimal external callus formation and a lack of bone bridging at 9 weeks. In contrast, the stimulated groups exhibited advanced healing with solid bone formation across the defect. This was confirmed quantitatively by a lower bone volume in the control group compared to the stimulated groups.The novel experimental model permits the application of a well-defined load history to an experimental bone fracture. The poor healing observed in the control group is consistent with under-stimulation. This study has shown early mechanical stimulation only is sufficient for a timely healing outcome. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1790-1796, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

New Insights into Early Cenozoic Carbon Cycling: Continental Ecosystem Response to Orbital Forcing in the Lacustrine Green River Formation (Western US) at the Conclusion of the Early Eocene Climatic Optimum

NASA Astrophysics Data System (ADS)

Musher, D.; Grogan, D. S.; Whiteside, J. H.

2010-12-01

A series of extreme warming events, known as hyperthermals, interrupted the equable climate conditions predominant during the early Cenozoic hothouse. In marine sediments, these hyperthermals are marked by prominent negative carbon isotope excursions, indicative of dramatic and abrupt changes in the global exogenic carbon pool, as well as carbonate dissolution horizons and benthic foraminiferal extinctions. Hyperthermals are well documented in the marine record, but it is less clear how patterns of global carbon cycling manifested in early Cenozoic terrestrial environments, although some studies have documented amplified excursions relative to that of the marine record. The lacustrine Eocene Green River Formation of Utah is an excellent system for studying the continental environmental context of global carbon cycle dynamics during this time. These sediments span a ~15 Myr time interval, including the entire Early Eocene Climatic Optimum (EECO) and the transition to the long-term Cenozoic cooling trend. To investigate the relationship between the continental carbon record and global carbon cycling, climate, and orbital forcing, we studied a detailed section from the P-4 core drilled in the Uinta Basin bracketing the famous “Mahogany Bed”, a petroliferous layer of oil shale recording a period of enhanced productivity and carbon burial near the end of the EECO. Our carbon isotope measurements of high molecular weight n-alkanes across this boundary suggest a stable global carbon cycle and climate regime persisting ~400 kyr at the terminal EECO. Frequency spectra of published oil yield and gamma ray data from this section reveal concentrated power at Milankovitch frequencies, permitting the assembly of a robust age model. In concert with radioisotopic age control, our orbital chronology allows for comparison of our carbon cycle record to early Eocene astronomical solutions. We show that the Mahogany Bed corresponds to strong minima in short and long eccentricity

Formation of laser-induced periodic surface structures (LIPSS) on tool steel by multiple picosecond laser pulses of different polarizations

NASA Astrophysics Data System (ADS)

Gregorčič, Peter; Sedlaček, Marko; Podgornik, Bojan; Reif, Jürgen

2016-11-01

Laser-induced periodic surface structures (LIPSS) are produced on cold work tool steel by irradiation with a low number of picosecond laser pulses. As expected, the ripples, with a period of about 90% of the laser wavelength, are oriented perpendicular to the laser polarization. Subsequent irradiation with the polarization rotated by 45° or 90° results in a corresponding rotation of the ripples. This is visible already with the first pulse and becomes almost complete - erasing the previous orientation - after as few as three pulses. The phenomenon is not only observed for single-spot irradiation but also for writing long coherent traces. The experimental results strongly defy the role of surface plasmon-polaritons as the predominant key to LIPSS formation.

Effect of light Sphagnum peat on odour formation in the early stages of biowaste composting.

PubMed

Kurola, Jukka M; Arnold, Mona; Kontro, Merja H; Talves, Matti; Romantschuk, Martin

2010-05-01

In the present study, we investigated the effects of two bulking materials, Sphagnum peat and pine wood chips, on the early stages of biowaste composting in two pilot-scale processes. Emphasis was placed on studying the formation conditions of malodorous compost gases in the initial phases of the processes. The results showed that gas emission leaving an open windrow and a closed drum composting system contained elevated concentrations of fermentative microbial metabolites when acid Sphagnum peat (pH 3.2) was used as a bulking material. Moreover, the gas emission of the peat amended drum composter contained a high concentration of odour (up to 450,000oum(-3) of air). The highest odour values in the outlet gas of peat amended composts coincided with the elevated concentrations of volatile organic compounds such as acetoin and buthanedion. We conclude that the acidifying qualities of composting substrates or bulking material may intensify odour emission from biowaste composts and prolong the early stages of the composting process. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

The Living Periodic Table

ERIC Educational Resources Information Center

Nahlik, Mary Schrodt

2005-01-01

To help make the abstract world of chemistry more concrete eighth-grade students, the author has them create a living periodic table that can be displayed in the classroom or hallway. This display includes information about the elements arranged in the traditional periodic table format, but also includes visual real-world representations of the…

Pharmacologic inhibition of phospholipase C in the brain attenuates early memory formation in the honeybee (Apis mellifera L.)

PubMed Central

Iino, Shiori; Kubo, Takeo

2018-01-01

ABSTRACT Although the molecular mechanisms involved in learning and memory in insects have been studied intensively, the intracellular signaling mechanisms involved in early memory formation are not fully understood. We previously demonstrated that phospholipase C epsilon (PLCe), whose product is involved in calcium signaling, is almost selectively expressed in the mushroom bodies, a brain structure important for learning and memory in the honeybee. Here, we pharmacologically examined the role of phospholipase C (PLC) in learning and memory in the honeybee. First, we identified four genes for PLC subtypes in the honeybee genome database. Quantitative reverse transcription-polymerase chain reaction revealed that, among these four genes, three, including PLCe, were expressed higher in the brain than in sensory organs in worker honeybees, suggesting their main roles in the brain. Edelfosine and neomycin, pan-PLC inhibitors, significantly decreased PLC activities in homogenates of the brain tissues. These drugs injected into the head of foragers significantly attenuated memory acquisition in comparison with the control groups, whereas memory retention was not affected. These findings suggest that PLC in the brain is involved in early memory formation in the honeybee. To our knowledge, this is the first report of a role for PLC in learning and memory in an insect. PMID:29330349

Single microfilaments mediate the early steps of microtubule bundling during preprophase band formation in onion cotyledon epidermal cells

PubMed Central

Takeuchi, Miyuki; Karahara, Ichirou; Kajimura, Naoko; Takaoka, Akio; Murata, Kazuyoshi; Misaki, Kazuyo; Yonemura, Shigenobu; Staehelin, L. Andrew; Mineyuki, Yoshinobu

2016-01-01

The preprophase band (PPB) is a cytokinetic apparatus that determines the site of cell division in plants. It originates as a broad band of microtubules (MTs) in G2 and narrows to demarcate the future division site during late prophase. Studies with fluorescent probes have shown that PPBs contain F-actin during early stages of their development but become actin depleted in late prophase. Although this suggests that actins contribute to the early stages of PPB formation, how actins contribute to PPB-MT organization remains unsolved. To address this question, we used electron tomography to investigate the spatial relationship between microfilaments (MFs) and MTs at different stages of PPB assembly in onion cotyledon epidermal cells. We demonstrate that the PPB actins observed by fluorescence microscopy correspond to short, single MFs. A majority of the MFs are bound to MTs, with a subset forming MT-MF-MT bridging structures. During the later stages of PPB assembly, the MF-mediated links between MTs are displaced by MT-MT linkers as the PPB MT arrays mature into tightly packed MT bundles. On the basis of these observations, we propose that the primary function of actins during PPB formation is to mediate the initial bundling of the PPB MTs. PMID:27053663

Old formation ages of igneous clasts on the L chondrite parent body reflect an early generation of planetesimals or chondrule formation

NASA Astrophysics Data System (ADS)

Crowther, Sarah A.; Filtness, Michal J.; Jones, Rhian H.; Gilmour, Jamie D.

2018-01-01

The Barwell meteorite contains large, abundant clasts that are igneous in nature. We report iodine-xenon ages of five clasts and one sample of host chondrite material. The fragment of host chondrite material yielded the oldest age determined: 4567.8 ± 1.2 Ma. Two clasts produced old, well defined ages of 4564.96 ± 0.33 Ma and 4565.60 ± 0.33 Ma. These, and a third clast having a less precise old age of 4566.0 ± 3.2 Ma, are interpreted as recording the timing of crystallisation of the samples. They were incorporated into the Barwell parent body before it underwent thermal metamorphism, but the I-Xe ages survived secondary processing on the parent body and were not reset by metamorphism, metasomatism or shock. Two further clasts record younger ages of 4560.96 ± 0.45 Ma and 4554.22 ± 0.38 Ma. These samples contain a high abundance of albitic mesostasis, and the most likely explanation of the ages is that they record the timing of metasomatism on the parent body. We also analysed four host chondrite samples that do not give I-Xe ages: in these samples, the system appears to have been disturbed by shock. It has been suggested previously that the igneous clasts are derived from an early generation of partially melted asteroids. We do not have direct evidence that the clasts we examined were necessarily derived from a partially differentiated body, only that they were derived from cooling of a silicate melt; the clasts could thus be the products of any one of several proposed models for chondrule formation. Our results indicate that processes akin to chondrule formation, in that they involve rapid cooling of a silicate melt, were ongoing at the same time as CAI formation, lending support to the suggestion that Al-Mg chondrule ages indicate either heterogeneous distribution of 26Al or resetting of the Al-Mg system after chondrule formation.

Sporadic sampling, not climatic forcing, drives observed early hominin diversity.

PubMed

Maxwell, Simon J; Hopley, Philip J; Upchurch, Paul; Soligo, Christophe

2018-05-08

The role of climate change in the origin and diversification of early hominins is hotly debated. Most accounts of early hominin evolution link observed fluctuations in species diversity to directional shifts in climate or periods of intense climatic instability. None of these hypotheses, however, have tested whether observed diversity patterns are distorted by variation in the quality of the hominin fossil record. Here, we present a detailed examination of early hominin diversity dynamics, including both taxic and phylogenetically corrected diversity estimates. Unlike past studies, we compare these estimates to sampling metrics for rock availability (hominin-, primate-, and mammal-bearing formations) and collection effort, to assess the geological and anthropogenic controls on the sampling of the early hominin fossil record. Taxic diversity, primate-bearing formations, and collection effort show strong positive correlations, demonstrating that observed patterns of early hominin taxic diversity can be explained by temporal heterogeneity in fossil sampling rather than genuine evolutionary processes. Peak taxic diversity at 1.9 million years ago (Ma) is a sampling artifact, reflecting merely maximal rock availability and collection effort. In contrast, phylogenetic diversity estimates imply peak diversity at 2.4 Ma and show little relation to sampling metrics. We find that apparent relationships between early hominin diversity and indicators of climatic instability are, in fact, driven largely by variation in suitable rock exposure and collection effort. Our results suggest that significant improvements in the quality of the fossil record are required before the role of climate in hominin evolution can be reliably determined. Copyright © 2018 the Author(s). Published by PNAS.

Probing Minor-merger-driven Star Formation In Early-type Galaxies Using Spatially-resolved Spectro-photometric Studies

NASA Astrophysics Data System (ADS)

Kaviraj, Sugata; Crockett, M.; Silk, J.; O'Connell, R. W.; Whitmore, B.; Windhorst, R.; Cappellari, M.; Bureau, M.; Davies, R.

2012-01-01

Recent studies that leverage the rest-frame ultraviolet (UV) spectrum have revealed widespread recent star formation in early-type galaxies (ETGs), traditionally considered to be old, passively-evolving systems. This recent star formation builds 20% of the ETG stellar mass after z 1, driven by repeated minor mergers between ETGs and small, gas-rich satellites. We demonstrate how spatially-resolved studies, using a combination of high-resolution UV-optical imaging and integral-field spectroscopy (IFS), is a powerful tool to quantify the assembly history of individual ETGs and elucidate the poorly-understood minor-merger process. Using a combination of WFC3 UV-optical (2500-8200 angstroms) imaging and IFS from the SAURON project of the ETG NGC 4150, we show that this galaxy experienced a merger with mass ratio 1:15 around 0.9 Gyr ago, which formed 3% of its stellar mass and a young kinematically-decoupled core. A UV-optical analysis of its globular cluster system shows that the bulk of the stars locked up in these clusters likely formed 6-7 Gyrs in the past. We introduce a new HST-WFC3 programme, approved in Cycle 19, which will leverage similar UV-optical imaging of a representative sample of nearby ETGs from SAURON to study the recent star formation and its drivers in unprecedented detail and put definitive constraints on minor-merger-driven star formation in massive galaxies at late epochs.

Korean Diaspora in the Age of Globalization: Early Study Abroad (ESA) College Students in the Midwest

ERIC Educational Resources Information Center

Choi, Hee Young

2012-01-01

This study examines the unique experiences of international Korean college students in the Midwest who have gone through the early study abroad (ESA) period in the US during their formative secondary school education and the influence of the experiences into their college lives in the mega campus. Two overarching research questions are: 1) how do…

Early diagenesis and authigenic mineral formation in mobile muds of the Changjiang Estuary and adjacent shelf

NASA Astrophysics Data System (ADS)

Zhao, Bin; Yao, Peng; Bianchi, Thomas S.; Xu, Yahong; Liu, Hui; Mi, Tiezhu; Zhang, Xiao-Hua; Liu, Jiwen; Yu, Zhigang

2017-08-01

Large-river delta-front estuaries (LDEs) and their adjacent shelf margins are sites of dynamic diagenetic processes that play a significant role in coastal biogeochemical cycling. In this study, we used dissolved inorganic carbon (DIC), redox sensitive elements (Fe2 + and Mn2 +), dissolved inorganic nitrogen (DIN) nutrients (NH4+, NO3-, and NO2-), major cations and anions (K+, Ca2 +, Mg2 +, SO42 -, and Cl-) in bottom-water and sediment pore-waters, to investigate the early chemical diagenesis and authigenic mineral formation in mobile-mud deposits of the Changjiang Estuary and adjacent inner shelf of the East China Sea (ECS). Vertical profiles of DIC and NH4+ in pore-waters had similar trends at most sites, showing a significant increase with depth near the Changjiang Estuary and being relatively constant at offshore sites. Higher pore-water DIC and NH4+ concentrations were observed in nearshore sites in winter, which were likely attributed to exposure of deeper deposits by winter coastal erosion. Nitrification was observed at most sites, and AOB (ammonia-oxidizing bacteria) played a leading role in ammonia oxidation in the study areas. The nitrification-denitrification was likely important in contributing to the loss of DIN in offshore sites during summer. Large inputs of organic carbon (OC) and terrestrial materials from Changjiang River resulted in intense sulfate reduction and Fe and Mn reduction in nearshore sites. Lower C/N and C/S ratios coupled with an apparent decrease in pore-water Ca2 + and Mg2+ concentrations with depth near the Changjiang Estuary, which indicated that authigenic carbonate formation occurs in these sediments. Decreases in K+ and Mg2 + with depth reflected that reverse weathering was an important process of authigenic mineral formation in these sediments. We conclude that adsorption process, seasonal erosion-redeposition, and summer hypoxic conditions of bottom-waters may play an important role in early diagenesis processes and

A new tephrochronology for early diverse stone tool technologies and long-distance raw material transport in the Middle to Late Pleistocene Kapthurin Formation, East Africa.

PubMed

Blegen, Nick; Jicha, Brian R; McBrearty, Sally

2018-05-09

The Middle to Late Pleistocene (780-10 ka) of East Africa records evidence of significant behavioral change, early fossils of Homo sapiens, and the dispersals of our species across and out of Africa. Studying human evolution in this time period thus requires an extensive and precise chronology relating behavioral evidence from archaeological sequences to aspects of hominin biology and evidence of past environments from fossils and geological sequences. Tephrochronology provides the chronostratigraphic resolution to achieve this through correlation and dating of volcanic ashes. The tephrochronology of the Kapthurin Formation presented here, based on tephra correlations and 40 Ar/ 39 Ar dates, provides new ages between 395.6 ± 3.5 ka and 465.3 ± 1.0 ka for nine sites showing diverse blade and Levallois methods of core reduction. These are >110 kyr older than previously known in East Africa. New 40 Ar/ 39 Ar dates provide a refined age of 222.5 ± 0.6 ka for early evidence of long-distance (166 km) obsidian transport at the Sibilo School Road Site. A tephra correlation between the Baringo and Victoria basins also provides a new date of ∼100 ka for the Middle Stone Age site of Keraswanin. By providing new and older dates for 11 sites containing several important aspects of hominin behavior and extending the chronology of the Kapthurin Formation forward by ∼130,000 years, the tephrochronology presented here contributes one of the longest and most refined chronostratigraphic frameworks of Middle through Late Pleistocene East Africa. This tephrochronology thus provides the foundation to understand the process of modern human behavioral evolution as it relates to biological and paleoenvironmental circumstances. Copyright © 2018 Elsevier Ltd. All rights reserved.

Leveraging Somali Basin Magnetic Anomalies to Constrain Gondwana Breakup and Early Indian Ocean Formation

NASA Astrophysics Data System (ADS)

Davis, J. K.; Lawver, L. A.; Norton, I. O.; Gahagan, L.

2015-12-01

The Somali Basin, found between the Horn of Africa and Madagascar was formed during the rifting of East and West Gondwana. Understanding the evolution of the basin has historically been hindered by enigmatic seafloor fabric and an apparent paucity of magnetic anomaly data. Recent iterations of satellite gravity data have revealed nearly complete fracture zones as well as a distinct extinct spreading ridge within the basin. Through a thorough compilation of available Somali Basin shiptrack profiles, we have been able to successfully model and interpret magnetic anomalies with exceptional detail. This complication is unrivaled in completeness and provides unprecedented insight into basin formation. Using this high quality data, we have interpreted magnetic anomalies M0r (120.8 Ma) to M24Bn (152.43 Ma) about the extinct ridge. The interpreted Somali Basin spreading rate and spreading direction, through anomaly M15n (135.76 Ma), are similar to those observed in the neighboring coeval Mozambique Basin. This similarity suggests that East Gondwana separated from West Gondwana as a cohesive unit, and that the internal rifting of East Gondwana began later around 135 Ma. Our magnetic anomaly interpretations have been combined with additional magnetic interpretations from around the Indian Ocean to build a regionally consistent plate model of Gondwana breakup and early Indian Ocean formation. This plate model will be crucial for future efforts unraveling a precise history of East Gondwana fragmentation and constraining the formation of the Enderby Basin offshore East Antarctica and Bay of Bengal offshore East India.

Old Dogs Learning New Tricks: Neuroplasticity Beyond the Juvenile Period

PubMed Central

Lillard, Angeline S.; Erisir, Alev

2014-01-01

Twenty years ago, the prevalent view in psychology was that although learning and the formation of new memories are lifelong occurrences, the neural changes associated with these events were all in the existing receptors. No new neural hardware, from synapses to neurons, was thought to appear after a protracted period early in life. In the past 20 years, another view has supplanted this one, showing that although the juvenile period is especially suited to neuroplastic adaptation, there is hard neuroplastic change later in life as well. We review a selection of evidence for this view from both animal and human models, showing how it reflects three principles of neuroplasticity: 1) earlier and later experience-induced changes to neuroarchitecture differ in degree more so than in type; 2) the types of experiences that lead to neuroplastic change narrow with age; and 3) differences in the amenability of neural circuitry to change result from basic differences in neuroarchitecture and neuroenvironment in different phases of development. PMID:24648605

Long-term impact of breast-feeding on body weight and glucose tolerance in children of diabetic mothers: role of the late neonatal period and early infancy.

PubMed

Rodekamp, Elke; Harder, Thomas; Kohlhoff, Rainer; Franke, Kerstin; Dudenhausen, Joachim W; Plagemann, Andreas

2005-06-01

Offspring of diabetic mothers (ODM) are at increased risk of developing overweight and impaired glucose tolerance (IGT). Recently, we observed that early neonatal ingestion of breast milk from diabetic mothers (DBM) may dose-dependently increase the risk of overweight in childhood. Here, we investigate whether DBM intake during the late neonatal period and early infancy also influences later adipogenic and diabetogenic risk in ODM. A total of 112 ODM were evaluated for influence of DBM ingestion during the late neonatal period (2nd-4th neonatal week) and early infancy on relative body weight (RBW) and glucose tolerance in early childhood. Exclusive breast-feeding was associated with increased childhood RBW (P = 0.011). Breast-fed ODM had an increased risk of overweight (odds ratio 1.98 [95% CI 1.12-3.50]). Breast-feeding duration was also positively related to childhood RBW (P = 0.004) and 120-min blood glucose during an oral glucose tolerance test (P = 0.022). However, adjustment for the DBM volume ingested during the early neonatal period, i.e., 1st week of life, eliminated all these relations with late neonatal breast-feeding and its duration. Interestingly, no relationship was observed between maternal blood glucose in the middle of the third trimester and the outcome. Neither late neonatal DBM intake nor the duration of breast-feeding has an independent influence on childhood risk of overweight or IGT in ODM. Therefore, the 1st week of life appears to be the critical window for nutritional programming in ODM by ingestion of maternal "diabetic" breast milk.

Field observation on secondary organic aerosols during Asian dust storm periods: Formation mechanism of oxalic acid and related compounds on dust surface

NASA Astrophysics Data System (ADS)

Wang, Gehui; Cheng, Chunlei; Meng, Jingjing; Huang, Yao; Li, Jianjun; Ren, Yanqin

2015-07-01

Chemical evolution of East Asian dust during transpacific transport has been given much attention for inorganic species such as sulfate, nitrate and ammonium. However, the role of organic species during the transport has almost entirely been ignored. To understand the formation mechanism of secondary organic aerosols (SOA) on dust surfaces, this study investigated the concentrations and compositions of dicarboxylic acids, keto-carboxylic acids, α-dicarbonyls and inorganic ions in size-segregated aerosols (9-stages) collected in Xi'an, central China during the two dust storm episodes in the springs of 2009 and 2011 and compared with those in nondust storm periods. During the events the ambient particulate dicarboxylic acids were 932-2240 ng m-3, which are comparable and even higher than those in nondust periods. Molecular compositions of the above SOA are similar to those in nondust periods with oxalic acid being the leading species. In the presence of the dust storms, all the above mentioned SOA species in Xi'an were predominantly enriched on the coarse particles (>2.1 μm), and oxalic acid well correlated with NO3- (R2 = 0.72, p < 0.001) rather than SO42-. This phenomenon differs greatly from the SOA in any other nondust period that is usually characterized by an enrichment of oxalic acid in fine mode and a strong correlation of oxalic acid with SO42-. We propose a formation pathway to explain these observations, in which nitric acid and/or nitrogen oxides react with dust to produce Ca(NO3)2 and form a liquid phase on the surface of dust aerosols via water vapor-absorption of Ca(NO3)2, followed by a partitioning of the gas-phase water-soluble organic precursors (e.g.,glyoxal and methylglyoxal) into the aqueous-phase and a subsequent oxidation into oxalic acid. To the best of our knowledge, we found for the first time the enrichment of glyoxal and methylglyoxal on dust surface. Our data suggest an important role of nitrate in the heterogeneous formation process of

Effects of combination of whey protein intake and rehabilitation on muscle strength and daily movements in patients with hip fracture in the early postoperative period.

PubMed

Niitsu, Masaya; Ichinose, Daisuke; Hirooka, Taku; Mitsutomi, Kazuhiko; Morimoto, Yoshitaka; Sarukawa, Junichiro; Nishikino, Shoichi; Yamauchi, Katsuya; Yamazaki, Kaoru

2016-08-01

Elderly patients can be at risk of protein catabolism and malnutrition in the early postoperative period. Whey protein includes most essential amino acids and stimulates the synthesis of muscle protein. The purpose of this study was to investigate the effect of resistance training in combination with whey protein intake in the early postoperative period. We randomized patients to a whey protein group or a control group. The former group received 32.2 g of whey protein pre- and post-rehabilitation in the early postoperative period for two weeks. Outcomes were knee extension strength on either side by Biodex 4.0, and the ability of transfer, walking, toilet use and stair use by the Barthel Index (BI). We performed initial and final assessments in the second and tenth rehabilitation sessions. A total of 38 patients were recruited: 20 in the whey protein group and 18 in the control group. Participants in the whey protein group showed significantly greater improvement in knee extension strength in the operated limb compared with the control group (F = 6.11, P = 0.02). The non-operated limb also showed a similar tendency (F = 3.51, P = 0.07). The abilities of transfer, walking and toilet use showed greater improvements in the whey protein group than in the control group by BI (P < 0.05). The combination of whey protein intake and rehabilitation for two weeks in the early postoperative period has a beneficial effect on knee extension strength in both lower limbs and BI (transfer, walking and toilet use) scores in patients with hip fracture. Copyright © 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Study of corrosion using long period fiber gratings coated with iron exposed to salty water

NASA Astrophysics Data System (ADS)

Coelho, L.; Santos, J. L.; Jorge, P. A. S.; de Almeida, J. M. M.

2017-04-01

A study of long period fiber gratings (LPFG) over coated with iron (Fe) and subjected to oxidation in water with different sodium chloride (NaCl) concentrations is presented. The formation of iron oxides and hydroxides was monitored in real time by following the features of the LPFG attenuation band. Preliminary results show that Fe coated LPFGs can be used as sensors for early warning of corrosion in offshore and in coastal projects where metal structures made of iron alloys are in contact with sea or brackish water.

Deoxyribonucleic Acid Replication and Expression of Early and Late Bacteriophage Functions in Bacillus subtilis

PubMed Central

Pène, Jacques J.; Marmur, Julius

1967-01-01

The role of deoxyribonucleic acid (DNA) replication in the control of the synthesis of deoxycytidylate (dCMP) deaminase and lysozyme in Bacillus subtilis infected with bacteriophage 2C has been studied. These phage-induced enzymes are synthesized at different times during the latent period. It was shown by actinomycin inhibition that the formation of the late enzyme (lysozyme) required messenger ribonucleic acid (mRNA) synthesized de novo after the initiation of translation of mRNA which specifies the early function (dCMP deaminase). The inhibition of phage DNA synthesis by mitomycin C prevented the synthesis of lysozyme only when added before the onset of phage DNA replication, but it did not affect the synthesis or action of dCMP deaminase when added at any time during the latent period. Treatment of infected cells with mitomycin C after phage DNA synthesis had reached 8 to 10% of its maximal rate resulted in the production of normal amounts of lysozyme. These observations suggest that mRNA specifying early enzymes can be transcribed from parental (and probably also from progeny) DNA, whereas late functional messengers can be transcribed only after the formation of progeny DNA. PMID:4990039

Evidence of liquid phase during laser-induced periodic surface structures formation induced by accumulative ultraviolet picosecond laser beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huynh, T. T. D.; Petit, A.; Semmar, N., E-mail: nadjib.semmar@univ-orleans.fr

2015-11-09

Laser-induced periodic surface structures (LIPSS) were formed on Cu/Si or Cu/glass thin films using Nd:YAG laser beam (40 ps, 10 Hz, and 30 mJ/cm{sup 2}). The study of ablation threshold is always achieved over melting when the variation of the number of pulses increases from 1 to 1000. But the incubation effect is leading to reduce the threshold of melting as increasing the number of laser pulse. Also, real time reflectivity signals exhibit typical behavior to stress the formation of a liquid phase during the laser-processing regime and helps to determine the threshold of soft ablation. Atomic Force Microscopy (AFM) analyses have shownmore » the topology of the micro-crater containing regular spikes with different height. Transmission Electron Microscopy (TEM) allows finally to show three distinguished zones in the close region of isolated protrusions. The central zone is a typical crystallized area of few nanometers surrounded by a mixed poly-crystalline and amorphous area. Finally, in the region far from the protrusion zone, Cu film shows an amorphous structure. The real time reflectivity, AFM, and HR-TEM analyses evidence the formation of a liquid phase during the LIPSS formation in the picosecond regime.« less

A magnificent circumcision carnival in the early 18th century Ottoman period.

PubMed

Verit, Ayhan; Cengiz, Mustafa; Yeni, Ercan; Unal, Dogan

2005-01-01

Circumcision has always been regarded as both an important social event and a milestone of a young man's life in Turkish culture, especially in the Ottoman period. Herein we study an exceptional circumcision festivity which lasted 15 days in the early autumn of the year 1720, for the 4 princes of Sultan III Ahmed, some sons of two high-ranking Ottoman officials and thousands of male children of poor citizens of Istanbul as representing the beneficent of the Sultan. All the organizations of the Empire participated in this huge event, including many shows and a feast, and the preparations were initiated months before. Traditionally, this kind of important social event of Ottoman culture had been described in a literary manner, and Surname-i Vehbi was the special name for the book of this circumcision festivity with 137 colored paintings and a total of 175 pages. The original of this work, which is in the library of Topkapi Palace Museum in Istanbul, was written by Vehbi and illustrated by Levni. The importance of this antique book is that it is the last important example of the illustrated festivity books of Ottoman literature.

The formation of galaxies

NASA Technical Reports Server (NTRS)

Efstathiou, G.; Silk, J.

1983-01-01

Current models of galaxy formation are examined in a review of recent observational and theoretical studies. Observational data on elliptical galaxies, disk galaxies, luminosity functions, clustering, and angular fluctuations in the cosmic microwave background are summarized. Theoretical aspects discussed include the origin and early evolution of small fluctuations, matter and radiation fluctuations, the formation of large-scale structure, dissipationless galaxy formation, galaxy mergers, dissipational galaxy formation, and the implications of particle physics (GUTs, massive neutrinos, and gravitinos) for cosmology.

Formation of silicides in annealed periodic multilayers

NASA Astrophysics Data System (ADS)

Maury, H.; Jonnard, P.; Le Guen, K.; André, J.-M.

2009-05-01

Periodic multilayers of nanometric period are widely used as optical components for the X-ray and extreme UV (EUV) ranges, in X-ray space telescopes, X-ray microscopes, EUV photolithography or synchrotron beamlines for example. Their optical performances depend on the quality of the interfaces between the various layers: chemical interdiffusion or mechanical roughness shifts the application wavelength and can drastically decrease the reflectance. Since under high thermal charge interdiffusion is known to get enhanced, the study of the thermal stability of such structures is essential to understand how interfacial compounds develop. We have characterized X-ray and EUV siliconcontaining multilayers (Mo/Si, Sc/Si and Mg/SiC) as a function of the annealing temperature (up to 600°C) using two non-destructive methods. X-ray emission from the silicon atoms, describing the Si valence states, is used to determine the chemical nature of the compounds present in the interphases while X-ray reflectivity in the hard and soft X-ray ranges can be related to the optical properties. In the three cases, interfacial metallic (Mo, Sc, Mg) silicides are evidenced and the thickness of the interphase increases with the annealing temperature. For Mo/Si and Sc/Si multilayers, silicides are even present in the as-prepared multilayers. Characteristic parameters of the stacks are determined: composition of the interphases, thickness and roughness of the layers and interphases if any. Finally, we have evidenced the maximum temperature of application of these multilayers to minimize interdiffusion.

Documenting the conversion from traditional to Studio Physics formats at the Colorado School of Mines: Process and early results

NASA Astrophysics Data System (ADS)

Kohl, Patrick B.; Kuo, H. Vincent; Ruskell, Todd G.

2008-10-01

The Colorado School of Mines (CSM) has taught its first-semester introductory physics course using a hybrid lecture/Studio Physics format for several years. Over the past year we have converted the second semester of our calculus-based introductory physics course (Physics II) to a Studio Physics format, starting from a traditional lecture-based format. In this paper, we document the early stages of this conversion in order to better understand which features succeed and which do not, and in order to develop a model for switching to Studio that keeps the time and resource investment manageable. We describe the recent history of the Physics II course and of Studio at Mines, discuss the PER-based improvements that we are implementing, and characterize our progress via several metrics, including pre/post Conceptual Survey of Electricity and Magnetism (CSEM) scores, Colorado Learning About Science Survey scores (CLASS), solicited student comments, failure rates, and exam scores.

Anticipatory eye movements and long-term memory in early infancy.

PubMed

Wong-Kee-You, Audrey M B; Adler, Scott A

2016-11-01

Advances in our understanding of long-term memory in early infancy have been made possible by studies that have used the Rovee-Collier's mobile conjugate reinforcement paradigm and its variants. One function that has been attributed to long-term memory is the formation of expectations (Rovee-Collier & Hayne, 1987); consequently, a long-term memory representation should be established during expectation formation. To examine this prediction and potentially open the door on a new paradigm for exploring infants' long-term memory, using the Visual Expectation Paradigm (Haith, Hazan, & Goodman, 1988), 3-month-old infants were trained to form an expectation for predictable color and spatial information of picture events and emit anticipatory eye movements to those events. One day later, infants' anticipatory eye movements decreased in number relative to the end of training when the predictable colors were changed but not when the spatial location of the predictable color events was changed. These findings confirm that information encoded during expectation formation are stored in long-term memory, as hypothesized by Rovee-Collier and colleagues. Further, this research suggests that eye movements are potentially viable measures of long-term memory in infancy, providing confirmatory evidence for early mnemonic processes. © 2016 Wiley Periodicals, Inc.

Trajectories of Identity Formation Modes and Their Personality Context in Adolescence.

PubMed

Topolewska-Siedzik, Ewa; Cieciuch, Jan

2018-04-01

Identity formation is a dynamic process during adolescence. Trajectories of identity formation were assessed longitudinally in early and middle adolescents, taking into account the personality underpinnings of this process. Identity formation was conceptualized according to the circumplex of identity formation modes. The model distinguishes basic modes rooted in Marcia's categories of exploration and commitment. Plasticity and stability, the two higher order Big Five meta-traits, were used to assess personality underpinnings. This study includes five measurement waves over 1.5 years and involves 1,839 Polish participants; 914 early adolescents (53.9% girls) and 925 middle adolescents (63.8% girls). The results suggest that (1) the four identity formation modes change dynamically, showing linear and curvilinear growth and that (2) identity formation mode trajectories are more dynamic in middle adolescence than in early adolescence. The results also showed that, in the conditional model, (3) the higher-order personality factors and gender affect the growth factors of identity formation modes. Overall, trajectories of identity formation modes are more linear during early adolescence and more curvilinear during middle adolescence. The initial levels in identity trajectories are influenced by the personality metatraits but only plasticity is related to change among early adolescents.

FGF signaling via MAPK is required early and improves Activin A-induced definitive endoderm formation from human embryonic stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sui, Lina, E-mail: linasui@vub.ac.be; Mfopou, Josue K.; Geens, Mieke

2012-09-28

Highlights: Black-Right-Pointing-Pointer Deep study the FGF signaling role during DE specification in the context of hESCs. Black-Right-Pointing-Pointer DE differentiation from hESCs has an early dependence on FGF signaling. Black-Right-Pointing-Pointer A serum-free DE protocol is developed based on the findings. Black-Right-Pointing-Pointer The DE cells showed potential to differentiate into pancreatic progenitor cells. -- Abstract: Considering their unlimited proliferation and pluripotency properties, human embryonic stem cells (hESCs) constitute a promising resource applicable for cell replacement therapy. To facilitate this clinical translation, it is critical to study and understand the early stage of hESCs differentiation wherein germ layers are defined. In this study,more » we examined the role of FGF signaling in Activin A-induced definitive endoderm (DE) differentiation in the absence of supplemented animal serum. We found that activated FGF/MAPK signaling is required at the early time point of Activin A-induced DE formation. In addition, FGF activation increased the number of DE cells compared to Activin A alone. These DE cells could further differentiate into PDX1 and NKX6.1 positive pancreatic progenitors in vitro. We conclude that Activin A combined with FGF/MAPK signaling efficiently induce DE cells in the absence of serum. These findings improve our understanding of human endoderm formation, and constitute a step forward in the generation of clinical grade hESCs progenies for cell therapy.« less

The seed of abundance and misery Peruvian living standards from the early republican period to the end of the guano era (1820-1880).

PubMed

Twrdek, Linda; Manzel, Kerstin

2010-07-01

This paper examines 19th-century Peruvian heights from the early republican period to the end of the guano era (1820-1880). Analyzing male and female prisoner heights from the Lima penitentiary, we find that the physical stature of the lower classes stagnated throughout the period. In spite of the substantial profits generated by Peru's chief export product, guano, these revenues apparently did not filter down to benefit ordinary laborers. 2010 Elsevier B.V. All rights reserved.

Pelvic floor morphometry and function in women with and without puborectalis avulsion in the early postpartum period.

PubMed

Cyr, Marie-Pierre; Kruger, Jennifer; Wong, Vivien; Dumoulin, Chantale; Girard, Isabelle; Morin, Mélanie

2017-03-01

Pelvic floor muscles are subject to considerable stretching during vaginal birth. In 13-36% of women, stretching results in avulsion injury whereby the puborectalis muscle disconnects from its insertion points on the pubis bone. Until now, few studies have investigated the effect of this lesion on pelvic floor muscles in the early postpartum period. The primary aim of this study was to compare pelvic floor muscle morphometry and function in primiparous women with and without puborectalis avulsion in the early postpartum period. Our secondary objective was to compare the 2 groups for pelvic floor disorders and impact on quality of life. In all, 52 primiparous women diagnosed with (n = 22) or without (n = 30) puborectalis avulsion injury were assessed at 3 months postpartum. Pelvic floor muscle morphometry was evaluated with 3-/4-dimensional transperineal ultrasound at rest, maximal contraction, and Valsalva maneuver. Different parameters were measured in the midsagittal and axial planes: bladder neck position, levator plate angle, anorectal angle, and levator hiatus dimensions. The dynamometric speculum was used to assess pelvic floor muscle function including: passive properties (passive forces and stiffness) during dynamic stretches, maximal strength, speed of contraction, and endurance. Pelvic floor disorder-related symptoms (eg, urinary incontinence, vaginal and bowel symptoms) and impact on quality of life were evaluated with the International Consultation on Incontinence Questionnaire and the Pelvic Floor Impact Questionnaire-Short Form. Pelvic Organ Prolapse Quantification was also assessed. In comparison to women without avulsion, women with avulsion presented an enlarged hiatus area at rest, maximal contraction, and Valsalva maneuver (P ≤ .013) and all other ultrasound parameters were found to be significantly altered during maximal contraction (P ≤ .014). They showed lower passive forces at maximal and 20-mm vaginal apertures as well as lower

Field Observation of Heterogeneous Formation of Dicarboxylic acids, Keto-carboxylic acids, α-Dicarbonyls and Nitrate in Xi'an, China during Asian dust storm periods

NASA Astrophysics Data System (ADS)

Wang, G.; Wang, J.; Ren, Y.; Li, J.

2015-12-01

To understand the formation mechanism of secondary organic aerosols (SOA) on dust surfaces, this study investigated the concentrations and compositions of dicarboxylic acids (C2-C11), keto-carboxylic acids (C3-C7), α-dicarbonyls and inorganic ions in size-segregated aerosols (9-stages) collected in Xi'an, China during the nondust storm and dust storm periods of 2009 and 2011. During the events the ambient particulate dicarboxylic acids were 932-2240 ng m-3, which are comparable and even higher than those in nondust periods. Molecular compositions of the above SOA are similar to those in nondust periods with oxalic acid being the leading species. In the presence of the dust storms, all the above mentioned SOA species in Xi'an were predominantly enriched on the coarse particles (>2.1μm), and oxalic acid well correlated with NO3- (R2=0.72, p<0.001) rather than SO42-.This phenomenon differs greatly from the SOA in any other nondust period that is characterized by an enrichment of oxalic acid in fine particles and a strong correlation of oxalic acid with SO42-. Our results further demonstrate that NO3- in the dust periods in Xi'an was mostly derived from secondary oxidation, whereas SO42- during the events was largely derived from surface soil of Gobi deserts. We propose a formation pathway to explain these observations, in which nitric acid and/or nitrogen oxides react with dust to produce Ca(NO3)2 and form a liquid phase on the surface of dust aerosols via water vapor-absorption of Ca(NO3)2, followed by a partitioning of the gas-phase water-soluble organic precursors (e.g.,glyoxal and methylglyoxal) into the aqueous-phase and a subsequent oxidation into oxalic acid. To the best of our knowledge, we found for the first time the enrichment of glyoxal and methylglyoxal on dust surface. Our data suggest an important role of nitrate in the heterogeneous formation process of SOA on the surface of Asian dust.

Analysis of Changes in the Glomerular Filtration Rate as Measured by the Cockroft-Gault Formula in the Early Period after Percutaneous Nephrolithotomy

PubMed Central

Seckiner, Ilker; Erturhan, Sakip M.; Mizrak, Sedat; Erbagci, Ahmet

2012-01-01

Purpose We aimed to analyze the changes in kidney function during the postoperative early period caused by the application of percutaneous nephrolithotomy (PNL), which is commonly used in kidney stone surgery. Materials and Methods PNL was performed in 80 patients (48 men, 32 women) with kidney stones. The mean age of the patients was 43.71 years (range, 18 to 71 years). Preoperative and postoperative values for stone size, glomerular filtration rate (GFR), serum creatinine, urea, electrolytes (Na, K, Cl), and Hb were compared in 80 patients in whom PNL surgery was performed. The formula of Cockroft-Gault was used to calculate the GFR during the early postoperative period (72 to 96 hours). Results Statistically significant decreases after PNL were observed in average stone size (preoperative, 627.75±375.10 mm2; postoperative, 81.70±16.15 mm2), serum urea (preoperative, 38.40±17.26 mg/dl; postoperative, 33.28±16.98 mg/dl), and creatinine (preoperative, 1.03±0.53 mg/dl; postoperative, 0.97±0.55 mg/dl) and an increase was observed in GFR (preoperative, 104.30±37.30 ml/min; postoperative, 112.38±40.1 ml/min). No changes were detected in the serum electrolyte values (Na, K, Cl). Multiple access, operation time, and type of lithotripter did not have any significant effects on the change in the GFR. Conclusions In light of our results, PNL for kidney stone operations appears to be a reliable and efficient method that provides recovery of kidney functions in the early post-operative period by increasing the GFR and with high stone-free rates. PMID:22950000

Period Variation in BW Vulpeculae (Abstract)

NASA Astrophysics Data System (ADS)

Cowall, D. E.; Odell, A. P.

2018-06-01

(Abstract only) BW Vulpeculae (BW Vul) has the largest amplitude of the beta Cephei stars. An observing campaign on this star using the AAVSOnetís Bright Star Monitor (BSM) telescopes was begun in December of 2015 and has yielded 66 nights of observations to date. A period analysis will be presented using the BSM data set in combination with unpublished data from the Lowell Observatory. Over almost 80 years of observations, BW Vul has closely followed a parabolic ephemeris (period increasing by 2.4 seconds/century) plus a light-travel-time effect. This parabola with excursions on either side also could be viewed as a sequence of straight lines (constant period) with abrupt period increases. The first paradigm predicted a necessary change in slope around 2004, which did not occur. Instead, the period decreased abruptly in 2009. That maximum occurred 250 minutes early compared to the first paradigm, and about 25 minutes early compared to the straight-line paradigm from 1982ñ2009.

The Intestinal Microbiome in Early Life: Health and Disease

PubMed Central

Arrieta, Marie-Claire; Stiemsma, Leah T.; Amenyogbe, Nelly; Brown, Eric M.; Finlay, Brett

2014-01-01

Human microbial colonization begins at birth and continues to develop and modulate in species abundance for about 3 years, until the microbiota becomes adult-like. During the same time period, children experience significant developmental changes that influence their health status as well as their immune system. An ever-expanding number of articles associate several diseases with early-life imbalances of the gut microbiota, also referred to as gut microbial dysbiosis. Whether early-life dysbiosis precedes and plays a role in disease pathogenesis, or simply originates from the disease process itself is a question that is beginning to be answered in a few diseases, including IBD, obesity, and asthma. This review describes the gut microbiome structure and function during the formative first years of life, as well as the environmental factors that determine its composition. It also aims to discuss the recent advances in understanding the role of the early-life gut microbiota in the development of immune-mediated, metabolic, and neurological diseases. A greater understanding of how the early-life gut microbiota impacts our immune development could potentially lead to novel microbial-derived therapies that target disease prevention at an early age. PMID:25250028

Adolescent Violent Victimization and Precocious Union Formation*

PubMed Central

C. Kuhl, Danielle; Warner, David F.; Wilczak, Andrew

2013-01-01

This article bridges scholarship in criminology and family sociology by extending arguments about “precocious exits” from adolescence to consider early union formation as a salient outcome of violent victimization for youths. Research indicates that early union formation is associated with several negative outcomes; yet the absence of attention to union formation as a consequence of violent victimization is noteworthy. We address this gap by drawing on life course theory and data from the National Longitudinal Study of Adolescent Health (Add Health) to examine the effect of violent victimization (“street” violence) on the timing of first co-residential union formation—differentiating between marriage and cohabitation—in young adulthood. Estimates from Cox proportional hazard models show that adolescent victims of street violence experience higher rates of first union formation, especially marriage, early in the transition to adulthood; however, this effect declines with age, as such unions become more normative. Importantly, the effect of violent victimization on first union timing is robust to controls for nonviolent delinquency, substance abuse, and violent perpetration. We conclude by discussing directions for future research on the association between violent victimization and coresidential unions with an eye toward the implications of such early union formation for desistance. PMID:24431471

Periodic Methods for Controlling a Satellite in Formation

DTIC Science & Technology

2002-03-01

5 5. Clohessy - Wiltshire Reference Frame................................................................... 10 6...techniques to study relative position errors within a satellite cluster [19, 24]. The dynamics were based on Clohessy - Wiltshire equations with near...dynamics model by solving the time periodic, linearized system using Floquet Theory. More accurate than the Clohessy - Wiltshire solutions used in previous

Planetary period oscillations in Saturn's magnetosphere: comments on the relation between post-equinox periods determined from magnetic field and SKR emission data

NASA Astrophysics Data System (ADS)

Cowley, S. W. H.; Provan, G.

2015-07-01

We discuss the properties of Saturn planetary period oscillations (PPOs) deduced from analysis of Saturn kilometric radiation (SKR) modulations by Fischer et al. (2014), and from prior analysis of magnetic field oscillations data by Andrews et al. (2012) and Provan et al. (2013), with emphasis on the post-equinox interval from early 2010 to early 2013. Fischer et al. (2014) characterize this interval as showing single phase-locked periods in the northern and southern SKR modulations observed in polarization-separated data, while the magnetic data generally show the presence of separated dual periods, northern remaining shorter than southern. We show that the single SKR period corresponds to the southern magnetic period early in 2010, segues into the northern period in late 2010, and returns to the southern period in mid-2012, approximately in line with changes in the dominant magnetic oscillation. An exception occurs in mid-February to late August 2011 when two periods are again discerned in SKR data, in good agreement with the ongoing dual periods in the magnetic data. Fischer et al. (2014) discuss this change in terms of a large jump in the southern SKR period related to the Great White Spot storm, which the magnetic data show is primarily due instead to a reappearance in the SKR data of the ongoing southern modulation in a transitory interval of resumed southern dominance. In the earlier interval from early April 2010 to mid-February 2011 when Fischer et al. (2014) deduce single phase-locked periods, we show unequivocal evidence in the magnetic data for the presence of separated dual oscillations of approximately equal amplitude. We suggest that the apparent single SKR periods result from a previously reported phenomenon in which modulations associated with one hemisphere appear in polarization-separated data associated with the other. In the following interval, mid-August 2011 to early April 2012, when Fischer et al. (2014) again report phase-locked northern

Trepanation in South-Central Peru during the early late intermediate period (ca. AD 1000-1250).

PubMed

Kurin, Danielle S

2013-12-01

This study evaluates trepanations from five well-contextualized prehistoric sites in the south-central highlands of Andahuaylas, Peru. The emergence of trepanation in this region coincides with the collapse of the Wari Empire, ca. ad 1000. Thirty-two individuals from Andahuaylas, AMS radiocarbon dated to the early Late Intermediate Period (ca. ad 1000-1250), were found to have 45 total trepanations. Various surgical techniques were being employed concurrently throughout the region. Scraping trepanations evinced the highest survival rate; circular grooving, drilling and boring, and linear cutting were far less successful. Evidence of perioperative procedures like hair shaving, poultice application, and possible cranioplasty use aimed to ensure the survival of a trepanation recipient. Postmortem trepanations, also present in Andahuaylas, were likely executed on corpses as a means of better understanding cranial anatomy and improving techniques. Similarities in trepanation patterns throughout the region attest to common motivations to engage in surgery. Although moderate physical head trauma seems to be the impetus for intervention in many cases of trepanation, other motivations included physiological and possibly psychosomatic factors. Nevertheless, treatment was not for everyone. In Andahuaylas, trepanations were withheld from subadults, females, and those individuals who practiced cranial modification. Copyright © 2013 Wiley Periodicals, Inc.

Periodic growth of bacterial colonies

NASA Astrophysics Data System (ADS)

Yamazaki, Yoshihiro; Ikeda, Takemasa; Shimada, Hirotoshi; Hiramatsu, Fumiko; Kobayashi, Naoki; Wakita, Jun-ichi; Itoh, Hiroto; Kurosu, Sayuri; Nakatsuchi, Michio; Matsuyama, Tohey; Matsushita, Mitsugu

2005-06-01

The formation of concentric ring colonies by bacterial species Bacillus subtilis and Proteus mirabilis has been investigated experimentally, focusing our attention on the dependence of local cell density upon the bacterial motility. It has been confirmed that these concentric ring colonies reflect the periodic change of the bacterial motility between motile cell state and immotile cell state. We conclude that this periodic change is macroscopically determined neither by biological factors (i.e., biological clock) nor by chemical factors (chemotaxis as inhibitor). And our experimental results strongly suggest that the essential factor for the change of the bacterial motility during concentric ring formation is the local cell density.

The effectiveness of Kinesio Taping® after total knee replacement in early postoperative rehabilitation period. A randomized controlled trial.

PubMed

Donec, V; Kriščiūnas, A

2014-08-01

The number of total knee replacements performed each year is increasing. Among the main impediments to functional recovery after these surgeries include postoperative edema, pain, lower limb muscle strength deficits, all of which point to a need to identify safe, effective postoperative rehabilitation modalities. The aim of this paper was to evaluate the effectiveness of Kinesio Taping® (KT) method in reducing postoperative pain, edema, and improved knee range of motion recovery after total knee replacement (TKR) operation in early postoperative rehabilitation period. Randomized clinical trial. Inpatient rehabilitation facility. Ninety-four patients, who underwent primary TKR surgery. Using simple randomization, participants were divided into KT group and control group. Both groups received same rehabilitation program and procedures after surgery, except KT group also received KT applications throughout all rehabilitation period. Postoperative pain, edema, restoration of the operated knee flexion and extension were evaluated. The chosen level of significance was P<0.05; in evaluation power of the test β ≤ 0.2. Groups were homogenous to sex, age, BMI, comorbidities, preoperative knee flexion/extension impairment, preoperative pain intensity, anaesthesia, prosthesis implanted (P>0.05). In both groups postoperative pain decreased significantly during rehabilitation period, however less pain was found in KT group from the second postoperative week till the end of inpatient rehabilitation (28th postoperative day) (P<0.05; β ≤ 0.2). Postoperative edema was less intense and subsided more quickly in KT group as well (P<0.05; β ≤ 0.2). No difference was found in improvement of knee flexion (P>0.05). Operated knee extension was found better in KT group then in control at the end of in-patient rehabilitation (P<0.05; β ≤ 0.2). KT was well tolerated by patients. KT technique appeared to be beneficial for reducing postoperative pain, edema, improving knee extension

Investigation on Periodically Surface-Corrugated Long-Period Gratings Inscribed on Photonic Crystal Fibers

NASA Astrophysics Data System (ADS)

Han, Young-Geun

2017-04-01

Transmission characteristics of periodically surface-corrugated long-period gratings (LPGs) inscribed on photonic crystal fibers (PCFs) using a wet-etching technique were experimentally investigated. A conventional wet method was implemented to periodically engrave the silica cladding region of the PCFs resulting in the periodic surface corrugation in the PCF. After applying the external strain to the PCF with the periodic surface micro-ridges, periodic modulation of refractive index based on the photoelastic effect is induced resulting in the formation of the PCF-based LPG. Increasing the applied strain successfully improves the extinction ratio of the resonant peak of the PCF-based LPG without the resonant wavelength shift. We also measured the transmission characteristics of the PCF-based LPG with variations in temperature and ambient index.

The Formation of Sulfate and Elemental Sulfur Aerosols Under Varying Laboratory Conditions: Implications for Early Earth

NASA Technical Reports Server (NTRS)

DeWitt, H. Langley; Hasenkopf, Christa A.; Trainer, Melissa G.; Farmer, Delphine K.; Jimenez, Jose L.; McKay, Christopher P.; Toon, Owen B.; Tolbert, Margaret A.

2010-01-01

The presence of sulfur mass-independent fractionation (S-MIF) in sediments more than 2.45 x 10(exp 9) years old is thought to be evidence for an early anoxic atmosphere. Photolysis of sulfur dioxide (SO2) by UV light with lambda < 220 nm has been shown in models and some initial laboratory studies to create a S-MIF; however, sulfur must leave the atmosphere in at least two chemically different forms to preserve any S-MIF signature. Two commonly cited examples of chemically different sulfur species that could have exited the atmosphere are elemental sulfur (S8) and sulfuric acid (H2S04) aerosols. Here, we use real-time aerosol mass spectrometry to directly detect the sulfur-containing aerosols formed when SO2 either photolyzes at wavelengths from 115 to 400 nm, to simulate the UV solar spectrum, or interacts with high-energy electrons, to simulate lightning. We found that sulfur-containing aerosols form under all laboratory conditions. Further, the addition of a reducing gas, in our experiments hydrogen (H2) or methane (CH4), increased the formation of S8. With UV photolysis, formation of S8 aerosols is highly dependent on the initial SO2 pressure; and S8 is only formed at a 2% SO2 mixing ratio and greater in the absence of a reductant, and at a 0.2% SO2 mixing ratio and greater in the presence of 1000 ppmv CH4. We also found that organosulfur compounds are formed from the photolysis of CH4 and moderate amounts of SO2, The implications for sulfur aerosols on early Earth are discussed.

Laser-induced periodic surface structures formation: investigation of the effect of nonlinear absorption of laser energy in different materials

NASA Astrophysics Data System (ADS)

Levy, Yoann; Bulgakova, Nadezhda M.; Mocek, Tomáš

2017-05-01

To get insight into laser-induced periodic surface structures (LIPSS) formation, the relaxation of a modulation in the temperature profile is investigated numerically on surfaces of two different kinds of materials (metals and dielectrics; gold and fused silica as examples) upon irradiation by ultrashort laser pulses. The temperature modulation is assumed to originate from the interference between the incoming laser pulse and the surface electromagnetic wave, which is considered as the main mechanism of LIPSS formation. For comparative studies of laser energy dissipation, a simplified 2D approach is used. It is based on the two-temperature model (TTM) and considers the mechanisms of nonlinear absorption of laser light (multiphoton ionization in fused silica; temperature-dependent thermophysical and optical properties in gold) and relaxation (electron trapping to excitonic states in fused silica). The TTM is coupled with the Drude model, considering the evolution of optical properties as a function of free-carrier density and/or temperature. The development and decay of the lattice temperature modulation, which can govern the LIPSS formation, is followed during electron-lattice thermalization time and beyond. It is shown that strong temperature gradients can form along the surfaces of both kinds of materials under study within the fluence range typical for LIPSS formation. Considerable changes in optical properties of these materials are found as a function of time, including metals, for which a constant reflectivity is usually assumed. Effects of nonlinear absorption on the surface temperature dynamics are reported.

Weed presence altered biotic stress and light signaling in maize even when weeds were removed early in the critical weed-free period

USDA-ARS?s Scientific Manuscript database

Weeds reduce crop yield even when there is no competition for resources. A phenomena known as the critical weed-free period (CWFP), which occurs early in the crop’s life cycle, is the essential interval when weed presence can reduce crop growth and yield. Even when weeds are removed after the CWFP, ...

Study of the formation of thermochemical laser-induced periodic surface structures on Cr, Ti, Ni and NiCr films under femtosecond irradiation

NASA Astrophysics Data System (ADS)

Dostovalov, A. V.; Korolkov, V. P.; Terentyev, V. S.; Okotrub, K. A.; Dultsev, F. N.; Babin, S. A.

2017-07-01

The formation of femtosecond laser-induced periodic surface structures (LIPSS's) on Cr, Ti, Ni and NiCr films (with different Cr contents) is investigated. It is established that thermochemical LIPSS's with periods of 950, 930 and 980 nm are formed, respectively, on the surfaces of titanium, chromium, and nichrome (with a chromium content of 20%); however, thermochemical LIPSS's are not formed on the surfaces of nickel and nichrome with a low chromium content, although Raman data indicate that oxidation occurs in all cases. A weakly ordered ablated structure with a period of 250-300 nm is found to be formed on oxidised areas of thermochemical LIPSS's in the case of chromium and nichrome (80/20). Experimental data on selective etching of thermochemical LIPSS's on titanium and chromium films are presented.

CYP3A activity based on plasma 4β-hydroxycholesterol during the early postpartum period has an effect on the plasma disposition of amlodipine.

PubMed

Naito, Takafumi; Kubono, Naoko; Ishida, Takuya; Deguchi, Shuhei; Sugihara, Masahisa; Itoh, Hiroaki; Kanayama, Naohiro; Kawakami, Junichi

2015-12-01

This study aimed to evaluate plasma 4β-hydroxycholesterol as an endogenous marker of CYP3A4/5 activity in early postpartum women and its impact on the plasma disposition of amlodipine. Twenty-seven early postpartum women treated with amlodipine for pregnancy-induced hypertension were enrolled. The plasma concentration of 4β-hydroxycholesterol and its ratio to cholesterol in postpartum and in non-perinatal women were evaluated. The predose plasma concentration of amlodipine was determined at steady state. The medians of the plasma 4β-hydroxycholesterol concentration at day 0-3 and 8-21 after delivery were 146 and 161 ng/mL, respectively. No significant difference was observed in the plasma concentration of 4β-hydroxycholesterol between the postpartum periods. The plasma concentration of 4β-hydroxycholesterol and its ratio to cholesterol in postpartum women were significantly higher than those in non-perinatal women. A large individual variability was observed in the dose-normalized plasma concentration of amlodipine in early postpartum women. A weak negative correlation was observed between the dose-normalized plasma concentration of amlodipine and the plasma concentration of 4β-hydroxycholesterol. In conclusion, early postpartum women possessed higher CYP3A activity based on plasma 4β-hydroxycholesterol and had a large pharmacokinetic variability in amlodipine. CYP3A activity during the early postpartum period had an effect on the plasma disposition of amlodipine. Copyright © 2015 The Japanese Society for the Study of Xenobiotics. Published by Elsevier Ltd. All rights reserved.

Chlorhexidine with or without alcohol against biofilm formation: efficacy, adverse events and taste preference.

PubMed

Santos, Gabriela Otero Dos; Milanesi, Fernanda Carpes; Greggianin, Bruna Frizon; Fernandes, Marilene Issa; Oppermann, Rui Vicente; Weidlich, Patricia

2017-05-04

In recent years, different chlorhexidine formulations have been tested, including an alcohol-free alternative, but the effect of this solution on early biofilm formation is not clear. A crossover, randomized, double-blind clinical trial was conducted to evaluate the effect of two chlorhexidine solutions against supra- and subgingival biofilm formation (NCT#02656251). Thirty-five participants were randomized and asked to rinse twice daily with 15 ml of an alcohol-containing 0.12% chlorhexidine solution, an alcohol-free 0.12% chlorhexidine solution, or placebo. The study was conducted in three experimental periods of 4 days each, with a 10-day washout between the periods. All the experimental periods followed the same protocol, except that the solutions were switched. Biofilm distribution was evaluated every 24 hours by the Plaque-Free Zone Index, during 96 hours. Adverse events were self-reported and sensory evaluation was performed using a hedonic scale. Compared to the placebo, the chlorhexidine solutions resulted in a significantly higher number of surfaces free of plaque over 96 hours (p < 0.01), and were able to prevent subgingival biofilm formation (p < 0.01). The alcohol-free chlorhexidine solution was associated with a lower incidence of adverse events, compared with alcohol-containing chlorhexidine (p < 0.05); it also received better sensory evaluation and acceptance by trial participants, compared with the alcohol-containing chlorhexidine (p = 0.007), and had a similar inhibitory effect on the formation of supra- and subgingival biofilms.

Formation of Valley Networks in a Cold and Icy Early Mars Climate: Predictions for Erosion Rates and Channel Morphology

NASA Astrophysics Data System (ADS)

Cassanelli, J.

2017-12-01

Mars is host to a diverse array of valley networks, systems of linear-to-sinuous depressions which are widely distributed across the surface and which exhibit branching patterns similar to the dendritic drainage patterns of terrestrial fluvial systems. Characteristics of the valley networks are indicative of an origin by fluvial activity, providing among the most compelling evidence for the past presence of flowing liquid water on the surface of Mars. Stratigraphic and crater age dating techniques suggest that the formation of the valley networks occurred predominantly during the early geologic history of Mars ( 3.7 Ga). However, whether the valley networks formed predominantly by rainfall in a relatively warm and wet early Mars climate, or by snowmelt and episodic rainfall in an ambient cold and icy climate, remains disputed. Understanding the formative environment of the valley networks will help distinguish between these warm and cold end-member early Mars climate models. Here we test a conceptual model for channel incision and evolution under cold and icy conditions with a substrate characterized by the presence of an ice-free dry active layer and subjacent ice-cemented regolith, similar to that found in the Antarctic McMurdo Dry Valleys. We implement numerical thermal models, quantitative erosion and transport estimates, and morphometric analyses in order to outline predictions for (1) the precise nature and structure of the substrate, (2) fluvial erosion/incision rates, and (3) channel morphology. Model predictions are compared against morphologic and morphometric observational data to evaluate consistency with the assumed cold climate scenario. In the cold climate scenario, the substrate is predicted to be characterized by a kilometers-thick globally-continuous cryosphere below a 50-100 meter thick desiccated ice-free zone. Initial results suggest that, with the predicted substrate structure, fluvial channel erosion and morphology in a cold early Mars

State Medicaid Early and Periodic Screening, Diagnosis, and Treatment guidelines: adherence to professionally recommended best oral health practices.

PubMed

Hom, Jacqueline M; Lee, Jessica Y; Silverman, Janice; Casamassimo, Paul S

2013-03-01

The authors evaluated the adherence of state Medicaid Early and Periodic Screening, Diagnosis, and Treatment (EPSDT) guidelines to recommended best oral health practices for infants and toddlers. The authors obtained state EPSDT guidelines via the Internet or from the Medicaid-CHIP State Dental Association, Washington. They identified best oral health practices through the American Academy of Pediatric Dentistry (AAPD), Chicago. They evaluated each EPSDT dental periodicity schedule with regard to the timing and content of seven key oral health domains. Thirty-two states and the District of Columbia (D.C.) had EPSDT dental periodicity schedules. With the exception of the dentist referral domain, 29 states (88 percent) adhered to the content and timing of best oral health practices, as established by the AAPD guideline. For the dentist referral domain, 31 of the 32 states and D.C. (94 percent) required referral of children to a dentist, but only 11 states (33 percent) adhered to best oral health practices by requiring referral by age 1 year. With the exception of the timing of the first dentist referral, there was high adherence to best oral health practices for infants and toddlers among states with separate EPSDT dental periodicity schedules. States with low adherence to best oral health practices, especially regarding the dental visit by age 1 year, can strengthen the oral health content of their EPSDT schedules by complying with the AAPD recommendations.

Metamorphic sole formation reveals plate interface rheology during early subduction

NASA Astrophysics Data System (ADS)

Mathieu, S.; Agard, P.; Dubacq, B.; Plunder, A.; Prigent, C.

2015-12-01

Metamorphic soles are m to ~500m thick tectonic slices welded beneath most large ophiolites. They correspond to highly to mildly deformed portions of oceanic lithosphere metamorphosed at amphibolite to granulite facies peak conditions. Metamorphic soles are interpreted as formed ≤1-2Ma after intraoceanic subduction initiation by heat transfer from the hot, incipient mantle wegde to the underthrusting lower plate. Their early accretion and exhumation together with the future ophiolite implies at least one jump of the subduction plate interface from above to below the metamorphic sole. Metamorphic soles thus represent one of the few remnants of the very early evolution of the subduction plate interface and provide major constraints on the thermal structure and the effective rheology of the crust and mantle along the nascent slab interface.We herein present a structural and petrological detailed description of the Oman and Turkey metamorphic soles. Both soles present a steep inverted metamorphic structure, with isograds subparallel to the peridotite contact, in which the proportion of mafic rocks, pressure and temperature conditions increase upward. They comprise, as most metamorphic soles worldwide, two main units: (1) a high-grade unit adjacent to the overlying peridotite composed of granulitized to amphibolized metabasalts, with rare metasedimentary interlayers (~800±100ºC at 10±2kbar) and (2) a low-grade greenschist facies unit composed of metasedimentary rocks with rare metatuffs (~500±100ºC at 5±2kbar). We provide for the first time refined P-T peak condition estimations by means of pseudosection modelling and maximum temperature constraints for the Oman low-grade sole by RAMAN thermometry. In order to quantify micro-scale deformations trough the sole, we also present EBSD data on the Oman garnet-bearing and garnet-free high-grade sole.With these new constraints, we finally propose a new conceptual mechanical model for metamorphic sole formation. This

Star formation and extinct radioactivities

NASA Technical Reports Server (NTRS)

Cameron, A. G. W.

1984-01-01

An assessment is made of the evidence for the existence of now-extinct radioactivities in primitive solar system material, giving attention to implications for the early stages of sun and solar system formation. The characteristics of possible disturbances in dense molecular clouds which can initiate the formation of cloud cores is discussed, with emphasis on these disturbances able to generate fresh radioactivities. A one-solar mass red giant star on the asymptotic giant branch appears to have been the best candidate to account for the short-lived extinct radioactivities in the early solar system.

Inhibitory effects of acid water prepared by an electrolysis apparatus on early plaque formation on specimens of dentine.

PubMed

Ito, K; Nishida, T; Murai, S

1996-05-01

The aim of this study was to compare the effects of acid water prepared by an electrolysis apparatus with placebo treatment on the ultrastructure of early plaque formed on dentine specimens attached to retainers in the oral cavity. Dentine specimens were taken from 12 healthy extracted human 3rd molars. 4 dentine specimens were placed in the both the right and left buccal flanges of retainers fabricated from self-setting acrylic resin. The retainers were placed on both maxillary buccal sites in 6 subjects. The test solution was acid water (AW) prepared by an electrolysis apparatus with a pH of 2.7 and an oxidation-reduction potential of more than 1100 mV. As a positive control, 0.2% chlorhexidine digluconate (CHX) solution was used and normal saline solution as a negative control. 4 specimens placed in the right and left retainers were randomly allocated to 4 treatments as follows: treatment A, washing with AW; treatment B, washing with CHX solution; treatment C, washing with normal saline; treatment D, no washing. Washing was carried out in a plastic beaker containing 30 ml of each solution for 30s 2X daily over a 7-day period. The specimens were then carefully removed from the retainers, the morphology and thickness of the plaque formed examined by SEM, and the developmental condition of the plaque analyzed statistically. The plaque on the specimens in treatments A and B consisted mainly of coccoid forms. Mature plaque formation with complex flora was seen on the specimens in treatments C and D. The mean thickness of the plaque deposits on the dentin specimens as measured on SEM photographs magnified 2000 times was 8.80 mm for treatment. A, while in treatment B it was 3.90 mm. Plaque thickness for treatment C was 24.97 mm, and for treatment D 25.67 mm. The thickness of plaque formed on the sectioned specimens was significantly less for treatments A and B than for treatments C and D. However, there was no statistically significant difference between treatments A

Early Diet and Later Cancer Risk: Prospective Associations of Dietary Patterns During Critical Periods of Childhood with the GH-IGF Axis, Insulin Resistance and Body Fatness in Younger Adulthood.

PubMed

Günther, Anke L B; Schulze, Matthias B; Kroke, Anja; Diethelm, Katharina; Joslowski, Gesa; Krupp, Danika; Wudy, Stefan; Buyken, Anette E

2015-01-01

Early life, adiposity rebound, and puberty represent critical growth periods when food choices could have long-term relevance for cancer risk. We aimed to relate dietary patterns during these periods to the growth hormone-insulin-like-growth-factor (GH-IGF) axis, insulin resistance, and body fatness in adulthood. Data from the Dortmund Nutritional and Anthropometric Longitudinally Designed (DONALD) Study participants with outcome data at 18-37 years, and ≥2 dietary records during early life (1-2 yr; n = 128), adiposity rebound (4-6 years, n = 179), or puberty (girls 9-14, boys 10-15 yr; n = 213) were used. Dietary patterns at these ages were derived by 1) reduced rank regression (RRR) to explain variation in adult IGF-I, IGF-binding protein-3 (IGFBP-3), homoeostasis model assessment for insulin resistance (HOMA-IR) and fat-mass index; 2) principal component analysis (PCA). Regarding RRR, the patterns "cake/canned fruit/cheese & eggs" (early life), "sweets & dairy" (adiposity rebound) and "high-fat foods" (pubertal boys) were independently associated with higher adult HOMA-IR. Furthermore, the patterns "favorable carbohydrate sources" (early life), "snack & convenience foods" (adiposity rebound), and "traditional & convenience carbohydrates" (pubertal boys) were related to adult IGFBP-3 (P trend < 0.01). PCA identified "healthy" patterns for all periods, but none was associated with the outcomes (P trend > 0.1). In conclusion, dietary patterns during sensitive growth periods may be of long-term relevance for adult insulin resistance and IGFBP-3.

Evidence for deep-water evaporite deposition in the Miocene Kareem Formation, Gemsa basin, eastern Egypt

DOE Office of Scientific and Technical Information (OSTI.GOV)

May, J.A.; Stonecipher, S.A.; Steinmetz, J.C.

1991-03-01

The correct interpretation of intercalated Miocene siliciclastics and evaporites of Gemsa basin is crucial for understanding early rift tectonics of the Gulf of Suez, pinpointing the timing of isolation of the Gulf from the Mediterranean, and developing exploration plays. Evaporites of the Kareem Formation comprise celestites and massive, 'chicken-wire,' and laminated anhydrites. Although previously interpreted as sabkha deposits; sedimentologic, petrographic, and paleontologic analyses indicate these evaporites more likely formed in a submarine setting. Marls that encase the evaporites contain a diverse and abundant assemblage of nannoplankton, planktonic foraminifera, diatoms, pteropods, and fish scales indicative of basinal deposition. Associated turbidites alsomore » denote deep-water sedimentation. The paucity of benthic diatoms and foraminifera, plus the presence of unburrowed shales, phosphate nodules, early ferroan carbonate cements, and authigenic pyrite, suggest periodic anoxic, or at least disaerobic, bottom waters. These sequences probably represent partial isolation of the Gulf of Suez by middle Miocene, producing periodic basin restriction and evaporative drawdown. Episodes of increasing salinity likely caused the progressive decreases in foram abundance and diversity in marls beneath the anhydrites, culminating in subaqueous evaporite formation. Diverse, indigenous nannoplankton assemblages from shale seams within the anhydrites suggest Gemsa basin was stratified; shallow open-marine conditions coexisted with anhydrite crystallization from deeper hypersaline waters.« less

Motives for early retirement of self-employed GPs in the Netherlands: a comparison of two time periods

PubMed Central

2012-01-01

Background The high cost of training and the relatively long period of training for physicians make it beneficial to stimulate physicians to retire later. Therefore, a better understanding of the link between the factors influencing the decision to retire and actual turnover would benefit policies designed to encourage later retirement. This study focuses on actual GP turnover and the determining factors for this in the Netherlands. The period 2003–2007 saw fewer GPs retiring from general practice than the period 1998–2002. In addition, GPs’ retirement age was higher in 2003–2007. For these two periods, we analysed work perception, objective workload and reasons for leaving, and related these with the probability that GPs would leave general practice at an early age. Methods In 2003, a first retrospective survey was sent to 520 self-employed GPs who had retired between 1998 and 2002. In 2008, the same survey was sent to 405 GPs who had retired between 2003 and 2007. The response rates were 60% and 54%, respectively. Analyses were done to compare work perception, objective workload, external factors and personal reasons for retiring. Results For both male and female GPs, work perception was different in the periods under scrutiny: both groups reported greater job satisfaction and a lower degree of emotional exhaustion in the later period, although there was no notable difference in subjective workload. The objective workload was lower in the second period. Moreover, most external factors and personal reasons that may contribute to the decision to retire were reported as less important in the second period. There was a stronger decrease in the probability that female GPs leave general practice within one year than for male GPs. This underscores the gender differences and the need for disaggregated data collection. Conclusions The results of this study suggest that the decrease in the probability of GPs leaving general practice within one year and the

Motives for early retirement of self-employed GPs in the Netherlands: a comparison of two time periods.

PubMed

Van Greuningen, Malou; Heiligers, Phil J M; Van der Velden, Lud F J

2012-12-18

The high cost of training and the relatively long period of training for physicians make it beneficial to stimulate physicians to retire later. Therefore, a better understanding of the link between the factors influencing the decision to retire and actual turnover would benefit policies designed to encourage later retirement. This study focuses on actual GP turnover and the determining factors for this in the Netherlands. The period 2003-2007 saw fewer GPs retiring from general practice than the period 1998-2002. In addition, GPs' retirement age was higher in 2003-2007. For these two periods, we analysed work perception, objective workload and reasons for leaving, and related these with the probability that GPs would leave general practice at an early age. In 2003, a first retrospective survey was sent to 520 self-employed GPs who had retired between 1998 and 2002. In 2008, the same survey was sent to 405 GPs who had retired between 2003 and 2007. The response rates were 60% and 54%, respectively. Analyses were done to compare work perception, objective workload, external factors and personal reasons for retiring. For both male and female GPs, work perception was different in the periods under scrutiny: both groups reported greater job satisfaction and a lower degree of emotional exhaustion in the later period, although there was no notable difference in subjective workload. The objective workload was lower in the second period. Moreover, most external factors and personal reasons that may contribute to the decision to retire were reported as less important in the second period. There was a stronger decrease in the probability that female GPs leave general practice within one year than for male GPs. This underscores the gender differences and the need for disaggregated data collection. The results of this study suggest that the decrease in the probability of GPs leaving general practice within one year and the increasing retirement age are caused by a decrease in

Cerebrovascular complications and granuloma formation after wrapping or coating of intracranial aneurysms with cotton gauze and human fibrin adhesives: results from a single-center patient series over a 5-year period.

PubMed

Beitzke, Markus; Leber, Klaus A; Deutschmann, Hannes; Gattringer, Thomas; Poltrum, Birgit; Fazekas, Franz

2013-10-01

Reinforcement of intracranial aneurysms (IAs) by wrapping or coating is a well-established therapeutic approach to those IAs not amenable to any other definitive treatment, but has been associated with complications such as parent artery narrowing, granuloma formation, and ischemic stroke. The goal of this study was to systematically investigate cerebrovascular complications following this procedure. The authors' hospital database was searched for all patients who underwent wrapping or coating of IAs with cotton gauze and human fibrin adhesives between October 2006 and October 2011. The follow-up records of these patients were extracted, including regular clinical visits and vascular imaging. Five hundred sixty-seven patients were treated for IAs over the 5-year period: 303 patients underwent endovascular strategies and 264 underwent craniotomies. Wrapping or coating of IAs was performed in 20 patients (3.5%). Parent artery narrowing occurred in 5 (25%) of the 20 patients and was associated with major ischemic strokes in 4 patients and severe headache in another. Ischemic strokes were associated with parent artery narrowing, which occurred early postoperatively in 2 patients or was a consequence of granuloma formation in 2 patients 1 and 2 months after the procedure, respectively. These data should add to the awareness of significant cerebrovascular complications following wrapping or coating of IAs with cotton gauze and human fibrin adhesives and indicate that major ischemic strokes need to be included in the risk/benefit considerations during decision making for such treatment strategies. Patients who receive IA wrapping should be monitored and followed up closely for arterial narrowing and granuloma formation.

The rapid formation of Sputnik Planitia early in Pluto's history.

PubMed

Hamilton, Douglas P; Stern, S A; Moore, J M; Young, L A

2016-11-30

Pluto's Sputnik Planitia is a bright, roughly circular feature that resembles a polar ice cap. It is approximately 1,000 kilometres across and is centred on a latitude of 25 degrees north and a longitude of 175 degrees, almost directly opposite the side of Pluto that always faces Charon as a result of tidal locking. One explanation for its location includes the formation of a basin in a giant impact, with subsequent upwelling of a dense interior ocean. Once the basin was established, ice would naturally have accumulated there. Then, provided that the basin was a positive gravity anomaly (with or without the ocean), true polar wander could have moved the feature towards the Pluto-Charon tidal axis, on the far side of Pluto from Charon. Here we report modelling that shows that ice quickly accumulates on Pluto near latitudes of 30 degrees north and south, even in the absence of a basin, because, averaged over its orbital period, those are Pluto's coldest regions. Within a million years of Charon's formation, ice deposits on Pluto concentrate into a single cap centred near a latitude of 30 degrees, owing to the runaway albedo effect. This accumulation of ice causes a positive gravity signature that locks, as Pluto's rotation slows, to a longitude directly opposite Charon. Once locked, Charon raises a permanent tidal bulge on Pluto, which greatly enhances the gravity signature of the ice cap. Meanwhile, the weight of the ice in Sputnik Planitia causes the crust under it to slump, creating its own basin (as has happened on Earth in Greenland). Even if the feature is now a modest negative gravity anomaly, it remains locked in place because of the permanent tidal bulge raised by Charon. Any movement of the feature away from 30 degrees latitude is countered by the preferential recondensation of ices near the coldest extremities of the cap. Therefore, our modelling suggests that Sputnik Planitia formed shortly after Charon did and has been stable, albeit gradually losing

The rapid formation of Sputnik Planitia early in Pluto's history

NASA Astrophysics Data System (ADS)

Hamilton, Douglas P.; Stern, S. A.; Moore, J. M.; Young, L. A.; Binzel, R. P.; Buie, M. W.; Buratti, B. J.; Cheng, A. F.; Ennico, K.; Grundy, W. M.; Linscott, I. R.; McKinnon, W. B.; Olkin, C. B.; Reitsema, H. J.; Reuter, D. C.; Schenk, P.; Showalter, M. R.; Spencer, J. R.; Tyler, G. L.; Weaver, H. A.

2016-12-01

Pluto's Sputnik Planitia is a bright, roughly circular feature that resembles a polar ice cap. It is approximately 1,000 kilometres across and is centred on a latitude of 25 degrees north and a longitude of 175 degrees, almost directly opposite the side of Pluto that always faces Charon as a result of tidal locking. One explanation for its location includes the formation of a basin in a giant impact, with subsequent upwelling of a dense interior ocean. Once the basin was established, ice would naturally have accumulated there. Then, provided that the basin was a positive gravity anomaly (with or without the ocean), true polar wander could have moved the feature towards the Pluto-Charon tidal axis, on the far side of Pluto from Charon. Here we report modelling that shows that ice quickly accumulates on Pluto near latitudes of 30 degrees north and south, even in the absence of a basin, because, averaged over its orbital period, those are Pluto's coldest regions. Within a million years of Charon's formation, ice deposits on Pluto concentrate into a single cap centred near a latitude of 30 degrees, owing to the runaway albedo effect. This accumulation of ice causes a positive gravity signature that locks, as Pluto's rotation slows, to a longitude directly opposite Charon. Once locked, Charon raises a permanent tidal bulge on Pluto, which greatly enhances the gravity signature of the ice cap. Meanwhile, the weight of the ice in Sputnik Planitia causes the crust under it to slump, creating its own basin (as has happened on Earth in Greenland). Even if the feature is now a modest negative gravity anomaly, it remains locked in place because of the permanent tidal bulge raised by Charon. Any movement of the feature away from 30 degrees latitude is countered by the preferential recondensation of ices near the coldest extremities of the cap. Therefore, our modelling suggests that Sputnik Planitia formed shortly after Charon did and has been stable, albeit gradually losing

Period doubling cascades of limit cycles in cardiac action potential models as precursors to chaotic early Afterdepolarizations.

PubMed

Kügler, Philipp; Bulelzai, M A K; Erhardt, André H

2017-04-04

Early afterdepolarizations (EADs) are pathological voltage oscillations during the repolarization phase of cardiac action potentials (APs). EADs are caused by drugs, oxidative stress or ion channel disease, and they are considered as potential precursors to cardiac arrhythmias in recent attempts to redefine the cardiac drug safety paradigm. The irregular behaviour of EADs observed in experiments has been previously attributed to chaotic EAD dynamics under periodic pacing, made possible by a homoclinic bifurcation in the fast subsystem of the deterministic AP system of differential equations. In this article we demonstrate that a homoclinic bifurcation in the fast subsystem of the action potential model is neither a necessary nor a sufficient condition for the genesis of chaotic EADs. We rather argue that a cascade of period doubling (PD) bifurcations of limit cycles in the full AP system paves the way to chaotic EAD dynamics across a variety of models including a) periodically paced and spontaneously active cardiomyocytes, b) periodically paced and non-active cardiomyocytes as well as c) unpaced and spontaneously active cardiomyocytes. Furthermore, our bifurcation analysis reveals that chaotic EAD dynamics may coexist in a stable manner with fully regular AP dynamics, where only the initial conditions decide which type of dynamics is displayed. EADs are a potential source of cardiac arrhythmias and hence are of relevance both from the viewpoint of drug cardiotoxicity testing and the treatment of cardiomyopathies. The model-independent association of chaotic EADs with period doubling cascades of limit cycles introduced in this article opens novel opportunities to study chaotic EADs by means of bifurcation control theory and inverse bifurcation analysis. Furthermore, our results may shed new light on the synchronization and propagation of chaotic EADs in homogeneous and heterogeneous multicellular and cardiac tissue preparations.

Early dust formation and a massive progenitor for SN 2011ja?

NASA Astrophysics Data System (ADS)

Andrews, J. E.; Krafton, Kelsie M.; Clayton, Geoffrey C.; Montiel, E.; Wesson, R.; Sugerman, Ben E. K.; Barlow, M. J.; Matsuura, M.; Drass, H.

2016-04-01

SN 2011ja was a bright (I = -18.3) Type II supernova occurring in the nearby edge on spiral galaxy NGC 4945. Flat-topped and multipeaked H α and H β spectral emission lines appear between 64 and 84 d post-explosion, indicating interaction with a disc-like circumstellar medium inclined ˜45° from edge-on. After day 84, an increase in the H- and K-band flux along with heavy attenuation of the red wing of the emission lines are strong indications of early dust formation, likely located in the cool dense shell created between the forward shock of the SN ejecta and the reverse shock created as the ejecta plows into the existing circumstellar material. Radiative transfer modelling reveals both ≈1 × 10-5 M⊙ of pre-existing dust located ˜1016.7 cm away and up to ≈6 × 10-4 M⊙ of newly formed dust. Spectral observations after 1.5 yr reveal the possibility that the fading SN is located within a young (3-6 Myr) massive stellar cluster, which when combined with tentative 56Ni mass estimates of 0.2 M⊙ may indicate a massive (≥25 M⊙) progenitor for SN 2011ja.

Development of Formal Agricultural Education in Canada (Based on the Analysis of Scientific Periodicals of the 19th-Early 20th Centuries)

ERIC Educational Resources Information Center

Havrylenko, Kateryna

2016-01-01

The article states that one of the world leaders in agricultural sector training is Canada, which has gained a great scientific and practical experience. The paper examines the role of periodicals of the 19th-early 20th centuries, preserved in the Canadian book funds for the establishment and development of formal agricultural education of this…

Early feed restriction of lambs modifies ileal epimural microbiota and affects immunity parameters during the fattening period.

PubMed

Frutos, J; Andrés, S; Yáñez-Ruiz, D R; Benavides, J; López, S; Santos, A; Martínez-Valladares, M; Rozada, F; Giráldez, F J

2018-04-22

Bacteria firmly attached to the gastrointestinal epithelium during the pre-weaning phase may show a significant impact on nutrient processing, immunity parameters, health and feed efficiency of lambs during post-weaning phases. Thus, the aim of this study was to describe the differences in the ileal epimural microbiota (e.g. total bacteria, Prevotella spp., Bifidobacterium spp. and Lactobacillus spp.) of fattening lambs promoted by early feed restriction during the suckling phase trying to elucidate some of the underlying mechanisms behind changes in feed efficiency during the fattening period. A total of 24 Merino lambs (average BW 4.81±0.256 kg) were used, 12 of them (ad libitum, ADL) kept permanently in individual pens with their mothers, whereas the other 12 lambs were separated from their dams for 9 h each day to be exposed to milk restriction (RES). After weaning (BW=15 kg) all the animals were penned individually, offered the same complete pelleted diet (35 g/kg BW per day) and slaughtered at a BW of 27 kg. During the fattening period, reduced gain : feed ratio (0.320 v. 0.261, P<0.001) was observed for the RES group. Moreover, increments of Prevotella spp. were detected in the ileal epimural microbiota of RES lambs (P<0.05). There were also higher numbers of infiltrated lymphocytes (T and B cells) in the ileal lamina propria (P<0.05), a higher M-cell labelling intensity in ileal Peyer's patches domes (P<0.05) and a trend towards a thickening of the submucosa layer when compared with the ADL group (P=0.057). Some other immunological parameters, such as an increased immunoglobulin A (IgA) production (pg IgA/µg total protein) and increments in CD45+ cells were also observed in the ileum of RES group (P<0.05), whereas transforming growth factor β and toll-like receptor gene expression was reduced (P<0.05). In conclusion, early feed restriction during the suckling phase promoted changes in ileal epimural microbiota and several immunity parameters that could

Early supra- and subgingival plaque formation in experimental gingivitis in smokers and never-smokers.

PubMed

Branco, Paula; Weidlich, Patricia; Oppermann, Rui Vicente; Rösing, Cassiano Kuchenbecker

2015-01-01

To evaluate supragingival and subgingival plaque formation on the dentogingival area in smokers and never smokers using the experimental gingivitis model and a plaque scoring system that considers the presence of an area free of plaque between plaque and the gingival sulcus called the plaque free zone (PFZ). Male volunteers, 9 current smokers and 10 never-smokers, refrained from oral hygiene procedures in the maxillary incisors and canines (test teeth) for 25 days. Under conditions of clinically healthy gingiva (phase 1) and gingival inflammation (phase 2), the supragingival plaque formation pattern was observed for 4 days in the dentogingival area. Gingival crevicular fluid was also measured. Plaque was dyed with fucsine and its presence was recorded by a calibrated examiner based on a 3-criteria scoring system: 0 - absence of stained plaque; 1 - presence of stained plaque and supragingival PFZ; 2 - presence of stained plaque and absence of PFZ, indicating that subgingival plaque formation has taken place. In both phases, smokers presented a significantly lower relative frequency of sites with subgingival plaque compared to never-smokers (P < 0.001). Mean gingival crevicular fluid was significantly higher in the presence of gingival inflammation for both groups (P = 0.001), whereas smokers demonstrated a significantly lower frequency of gingival bleeding than did non-smokers (23.6% vs 66.1%; P < 0.001). Smokers presented significantly lower percentages of sites with subgingival plaque in all experimental periods and presented less gingival inflammation as shown by GBI and gingival crevicular fluid quantification.

Suppression pheromone and cockroach rank formation

NASA Astrophysics Data System (ADS)

Kou, Rong; Chang, Huan-Wen; Chen, Shu-Chun; Ho, Hsiao-Yung

2009-06-01

Although agonistic behaviors in the male lobster cockroach ( Nauphoeta cinerea) are well known, the formation of an unstable hierarchy has long been a puzzle. In this study, we investigate how the unstable dominance hierarchy in N. cinerea is maintained via a pheromone signaling system. In agonistic interactions, aggressive posture (AP) is an important behavioral index of aggression. This study showed that, during the formation of a governing hierarchy, thousands of nanograms of 3-hydroxy-2-butanone (3H-2B) were released by the AP-adopting dominant in the first encounter fight, then during the early domination period and that this release of 3H-2B was related to rank maintenance, but not to rank establishment. For rank maintenance, 3H-2B functioned as a suppression pheromone, which suppressed the fighting capability of rivals and kept them in a submissive state. During the period of rank maintenance, as the dominant male gradually decreased his 3H-2B release, the fighting ability of the subordinate gradually developed, as shown by the increasing odds of a subordinate adopting an AP (OSAP). The OSAP was negatively correlated with the amount of 3H-2B released by the dominant and positively correlated with the number of domination days. The same OSAP could be achieved earlier by reducing the amount of 3H-2B released by the dominant indicates that whether the subordinate adopts an offensive strategy depends on what the dominant is doing.

Incidence, etiology, and significance of acute kidney injury in the early post-kidney transplant period.

PubMed

Panek, Romuald; Tennankore, Karthik K; Kiberd, Bryce A

2016-01-01

Little is known about the incidence, causes, and significance of acute kidney injury (AKI) in the early transplant period. This study used a definition as >26 μmol/L increase in creatinine within 48 h or >50% increase over a period >48 h. In 326 adult consecutive recipients of a solitary kidney transplant from 2006 to 2014 followed at this center, 21% developed AKI within the first six months. Most etiologies were CNI toxicity (33%) or unknown (26%), whereas acute rejection accounted for 17% and urinary tract obstruction for 10%. Those with AKI had a significantly lower glomerular filtration rate (GFR) at one-yr post-transplant (adjusted beta coefficient -5.5 mL/min/1.73 m(2) , 95% CI: -10.4, -0.7, p = 0.025) in a multivariable linear regression model. However, the AKI definition missed 6 of 19 episodes of acute rejection and 4 of 10 episodes of urinary tract obstruction. When acute rejection (including those that did not satisfy AKI criteria) was included in the model, other causes of AKI were not significantly associated with GFR at year 1. Although AKI, using current criteria, is likely to be a significant predictor of later outcomes, important causes are missed and the criteria are not sensitive for clinical decision-making. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

[The complex approach to the rehabilitation of post-stroke patients with movement disorders in the early rehabilitation period].

PubMed

Khabirov, F A; Khaĭbullin, T I; Grigor'eva, O V

2011-01-01

We studied 110 patients, aged 34-71 years, in the early rehabilitation period after stroke who were admitted to a rehabilitation neurologic department of Kazan. The rehabilitation approach was based on the combination of several methods: kinesitherapy, transcranial magnetic stimulation and cerebrolysin treatment. This complex reanimation allowed to achieve the marked functional restoration of movement abilities in many cases that was correlated with the normalization of brain bioelectric activity (the increase of alpha-rhythm spectral power, the decrease of slow-wave EEG components). The combined use of these three methods was more effective than a combination of any two of them.

Primordial Black Holes from Supersymmetry in the Early Universe.

PubMed

Cotner, Eric; Kusenko, Alexander

2017-07-21

Supersymmetric extensions of the standard model generically predict that in the early Universe a scalar condensate can form and fragment into Q balls before decaying. If the Q balls dominate the energy density for some period of time, the relatively large fluctuations in their number density can lead to formation of primordial black holes (PBH). Other scalar fields, unrelated to supersymmetry, can play a similar role. For a general charged scalar field, this robust mechanism can generate black holes over the entire mass range allowed by observational constraints, with a sufficient abundance to account for all dark matter in some parameter ranges. In the case of supersymmetry the mass range is limited from above by 10^{23}  g. We also comment on the role that topological defects can play for PBH formation in a similar fashion.

Oman metamorphic sole formation reveals early subduction dynamics

NASA Astrophysics Data System (ADS)

Soret, Mathieu; Agard, Philippe; Dubacq, Benoît; Plunder, Alexis; Ildefonse, Benoît; Yamato, Philippe; Prigent, Cécile

2016-04-01

Metamorphic soles correspond to m to ~500m thick tectonic slices welded beneath most of the large-scale ophiolites. They typically show a steep inverted metamorphic structure where the pressure and temperature conditions of crystallization increase upward (from 500±100°C at 0.5±0.2 GPa to 800±100°C at 1.0±0.2 GPa), with isograds subparallel to the contact with the overlying ophiolitic peridotite. The proportion of mafic rocks in metamorphic soles also increases from the bottom (meta-sediments rich) to the top (approaching the ophiolite peridotites). These soles are interpreted as the result of heat transfer from the incipient mantle wedge toward the nascent slab (associated with large-scale fluid transfer and possible shear heating) during the first My of intra-oceanic subduction (as indicated by radiometric ages). Metamorphic soles provide therefore major constraints on early subduction dynamics (i.e., thermal structure, fluid migration and rheology along the nascent slab interface). We present a detailed structural and petrological study of the metamorphic sole from 4 major cross-sections along the Oman ophiolite. We show precise pressure-temperature estimates obtained by pseudosection modelling and EBSD measurements performed on both the garnet-bearing and garnet-free high-grade sole. Results allow quantification of the micro-scale deformation and highlight differences in pressure-temperature-deformation conditions between the 4 different locations, showing that the inverted metamorphic gradient through the sole is not continuous in all locations. Based on these new constraints, we suggest a new tectonic-petrological model for the formation of metamorphic soles below ophiolites. This model involves the stacking of several homogeneous slivers of oceanic crust leading to the present-day structure of the sole. In this view, these thrusts are the result of rheological contrasts between the sole and the peridotite as the plate interface progressively cools down

JOVIAN EARLY BOMBARDMENT: PLANETESIMAL EROSION IN THE INNER ASTEROID BELT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turrini, D.; Coradini, A.; Magni, G., E-mail: diego.turrini@ifsi-roma.inaf.it

The asteroid belt is an open window on the history of the solar system, as it preserves records of both its formation process and its secular evolution. The progenitors of the present-day asteroids formed in the Solar Nebula almost contemporary to the giant planets. The actual process producing the first generation of asteroids is uncertain, strongly depending on the physical characteristics of the Solar Nebula, and the different scenarios produce very diverse initial size-frequency distributions (SFDs). In this work, we investigate the implications of the formation of Jupiter, plausibly the first giant planet to form, on the evolution of themore » primordial asteroid belt. The formation of Jupiter triggered a short but intense period of primordial bombardment, previously unaccounted for, which caused an early phase of enhanced collisional evolution in the asteroid belt. Our results indicate that this Jovian Early Bombardment caused the erosion or the disruption of bodies smaller than a threshold size, which strongly depends on the SFD of the primordial planetesimals. If the asteroid belt was dominated by planetesimals less than 100 km in diameter, the primordial bombardment would have caused the erosion of bodies smaller than 200 km in diameter. If the asteroid belt was instead dominated by larger planetesimals, the bombardment would have resulted in the destruction of bodies as big as 500 km.« less

The formation of giant planets and its effects on protoplanetary disks: the case of Jupiter and the Jovian Early Bombardment

NASA Astrophysics Data System (ADS)

Turrini, D.; ISSI Team "Vesta, the key to the origins of the Solar System"; EChO "Planetary Formation" Working Group

The formation of giant planets is accompanied by a short but intense primordial bombardment \\citep{safronov69,weidenschilling75,weidenschilling01,turrini11}: the prototype for this class of events is the Jovian Early Bombardment (JEB) caused by the formation of Jupiter in the Solar System \\citep{turrini11,turrini12}. The JEB affected the collisional evolution of the minor bodies in the inner Solar System by inflicting mass loss to planetesimals \\citep{turrini12,turrini14a,turrini14b} due to cratering erosion and, at the same time, delivering water and volatile materials to the asteroid belt \\citep{turrini14b}. The JEB also resulted in a significant number of collisions between Jupiter and planetesimals formed over a wide orbital range, delivering volatile and refractory materials to the giant planet and its circumplanetary disk \\citep{turrini14c}. In this talk I'll discuss how the study of the effects of the JEB on Vesta can be used to constrain the early evolution of the Solar System \\citep{turrini14a,turrini14b} and how these constraints can, in turn, provide insight on the composition of Jupiter and of its satellites. Finally, I'll discuss the implications of the JEB model for extrasolar planets \\citep{turrini14c}.

Effect of insulin-like growth factor-I during the early postnatal period in intrauterine growth-restricted rats.

PubMed

Ikeda, Naho; Shoji, Hiromichi; Suganuma, Hiroki; Ohkawa, Natsuki; Kantake, Masato; Murano, Yayoi; Sakuraya, Koji; Shimizu, Toshiaki

2016-05-01

Insulin-like growth factor-I (IGF-I) is essential for perinatal growth and development; low serum IGF-I has been observed during intrauterine growth restriction (IUGR). We investigated the effects of recombinant human (rh) IGF-I in IUGR rats during the early postnatal period. Intrauterine growth restriction was induced by bilateral uterine artery ligation in pregnant rats. IUGR pups were divided into two groups injected daily with rhIGF-I (2 mg/kg; IUGR/IGF-I, n = 16) or saline (IUGR/physiologic saline solution (PSS), n = 16) from postnatal day (PND) 7 to 13. Maternal sham-operated pups injected with saline were used as controls (control, n = 16). Serum IGF-I and IGF binding proteins (IGFBP) 3 and 5 were measured on PND25. The expression of Igf-i, IGF-I receptor (Igf-ir), Igfbp3, and 5 mRNA in the liver and brain was measured using real-time polymerase chain reaction on PND25. Immunohistochemical staining of the liver for IGF expression was performed. Mean bodyweight on PND3 and PND25 in the IUGR pups (IUGR/IGF-I and IUGR/PSS) was significantly lower than that of the control pups. Serum IGF-I and hepatic Igf-ir mRNA in the IUGR pups were significantly lower than those in the control pups. In the IUGR/IGF-I group, hepatic Igfbp3 mRNA and liver immunohistochemical staining were increased. In the IUGR/PSS and control pups, there were no significant differences between these two groups in serum IGFBP3 and IGFBP5, hepatic Igf-i and Igfbp-5 mRNA, or brain Igf mRNA. No benefits on body and brain weight gain but an effective increase in hepatic IGFBP-3 was observed after treatment with 2 mg/kg rhIGF-I during the early postnatal period. © 2015 Japan Pediatric Society.

Early Earth differentiation [rapid communication

NASA Astrophysics Data System (ADS)

Walter, Michael J.; Trønnes, Reidar G.

2004-09-01

The birth and infancy of Earth was a time of profound differentiation involving massive internal reorganization into core, mantle and proto-crust, all within a few hundred million years of solar system formation ( t0). Physical and isotopic evidence indicate that the formation of iron-rich cores generally occurred very early in planetesimals, the building blocks of proto-Earth, within about 3 million years of t0. The final stages of terrestrial planetary accretion involved violent and tremendously energetic giant impacts among core-segregated Mercury- to Mars-sized objects and planetary embryos. As a consequence of impact heating, the early Earth was at times partially or wholly molten, increasing the likelihood for high-pressure and high-temperature equilibration among core- and mantle-forming materials. The Earth's silicate mantle harmoniously possesses abundance levels of the siderophile elements Ni and Co that can be reconciled by equilibration between iron alloy and silicate at conditions comparable to those expected for a deep magma ocean. Solidification of a deep magma ocean possibly involved crystal-melt segregation at high pressures, but subsequent convective stirring of the mantle could have largely erased nascent layering. However, primitive upper mantle rocks apparently have some nonchondritic major and trace element refractory lithophile element ratios that can be plausibly linked to early mantle differentiation of ultra-high-pressure mantle phases. The geochemical effects of crystal fractionation in a deep magma ocean are partly constrained by high-pressure experimentation. Comparison between compositional models for the primitive convecting mantle and bulk silicate Earth generally allows, and possibly favors, 10-15% total fractionation of a deep mantle assemblage comprised predominantly of Mg-perovskite and with minor but geochemically important amounts of Ca-perovskite and ferropericlase. Long-term isolation of such a crystal pile is generally

Acceptance of Illness after Surgery in Patients with Breast Cancer in the Early Postoperative Period.

PubMed

Nowicki, Andrzej; Krzemkowska, Elżbieta; Rhone, Piotr

2015-11-01

The breast cancer is the most common cancer in women, both in Poland and in the world. Consequences entail a disruption in the physical, psychological and social functioning. The aim of the study was to assess the acceptance of illness by patients treated for breast cancer in the early postoperative period. The research was conducted on the group of 100 consecutive patients aged 32-80 years (median 56 years) who underwent surgery for breast cancer in the Centre of Oncology in Bydgoszcz w 2014 roku. 68 of women had mastectomy, 32 of women had conservative surgery. Polling was conducted in the early period after surgery. The original questionnaire containing closed questions the scale of acceptance of the disease (AIS) as well as mental adaptation to cancer (Mini-Mac) was used in the study. 38% of patients had high acceptance of the disease, 48% average and 14% had low acceptance. Patients after conservative surgery had a higher average values for the mental strategies to cope with the disease, for the fighting spirit (23.1), helplessness and hopelessness (13.5), positive revaluation (23), the patients had a lower average (16.5) in the strategy to absorb anxiety. Patients after conservative surgery had a higher average for constructive style (2.6) but lower for destructive style (1.5). High level of mental coping with the disease was observed in 53%of patients with constructive style and 4% of patients with destructive style. While, a low level of mental coping with the dosease was observed in 5% of patients with constructive style and 46% of patients with destructive style. Almost half of women after mastectomy or conservative surgery had an average acceptance of the disease. The disease was accepted best by educated women living in the cities, white-collar workers with a good economic situation. The following factors were affected the better management of the disease, in order: age, education, current occupation and economic situation, while the type of surgery did

Setting the Periodic Table.

ERIC Educational Resources Information Center

Saturnelli, Annette

1985-01-01

Examines problems resulting from different forms of the periodic table, indicating that New York State schools use a form reflecting the International Union of Pure and Applied Chemistry's 1984 recommendations. Other formats used and reasons for standardization are discussed. (DH)

The early Holocene humid period in the Tayma palaeolake, NW Arabian Peninsula -- A high-resolution micro-facies and geochemical approach

NASA Astrophysics Data System (ADS)

Neugebauer, Ina; Plessen, Birgit; Dinies, Michèle; Engel, Max; Tjallingii, Rik; Brauer, Achim

2016-04-01

The Tayma palaeolake is a rare archive of the early Holocene humid period in northern Arabia (Dinies et al. 2015; Engel et al. 2012). Here we present a ca. 1 m thick and 500 years spanning annually laminated sediment section that was deposited in the centre of the former lake from ca. 8500 to 8000 calibrated years (cal. yrs) BP, as determined by AMS 14C dating of pollen concentrates (Dinies et al. 2015). High-resolution micro-facies analyses based on thin section microscopy, μXRF element scanning, δ18Ocarb and δ13Ccarb measurements on single carbonate laminae, as well as geochemical measurements on bulk samples for TOC, CaCO3, C/N ratio, δ18Ocarb, δ13Ccarb, δ13Corg and δ15N determination were performed in order to investigate the sedimentological and geochemical changes along the varved sequence in great detail. The finely laminated marl sediments are mainly composed of sub-mm thick laminae of endogenic aragonite, organic matter and diatoms, as well as occasional, often graded silt-clay layers. Following an early lake phase from ca. 8700 to 8500 cal. yrs BP characterized by coarsely laminated, presumably non-annual marl sediments that are rich in ostracods, three main varved phases can be distinguished within the investigated section: (1) aragonitic-organic varves from ca. 8500 to 8300 cal. yrs BP, (2) diatom-organic varves from ca. 8300 to 8100 cal. yrs BP that frequently include aragonite laminae and occasionally gastropod and ostracod shells, and (3) organic varves from ca. 8100 to 8000 cal. yrs BP with decreasing diatom and aragonite laminae and an increasing frequency of gypsum layers. After this period, gypsum becomes abundant and fine lamination appears only sporadically. In addition, we observe increasing trends of TOC, C/N and δ13Ccarb and decreasing δ18Ocarb during phase 1 and excess δ18Ocarb, δ13Ccarb and TOC values during phase 2, pointing towards the maximum lake productivity and increased seasonal precipitation. We interpret this

Anatomy in Cologne--Institutional development and body supply from the Weimar Republic to the early post-war period.

PubMed

Kaiser, Stephanie; Gross, Dominik

2015-07-01

The Anatomical Institute of the University of Cologne was founded in 1925. This paper highlights its institutional development and the sources from which it procured bodies for dissection. A comparison is drawn between the first years of the institute's existence during the Weimar Republic (1925-1932) and its rebuilding after war damage in the early post-war period (1947-1954). The institute and its procurement of bodies have not previously been investigated for these two time periods. The Third Reich, for which a detailed study already exists, will be mentioned as well to allow better evaluation of the periods before and after National Socialism. Based on newly evaluated archival material and body journals which will be examined both quantitatively and qualitatively, it becomes apparent that the Cologne institute experienced a chronic shortage of bodies both during the Weimar Republic and the first post-war decade (even though the delivery facilities were mostly the same). However, the situation of the institute in terms of structure, organization and personnel as well as body supply in the aftermath of World War II proved much more challenging than during the time of the Weimar Republic. Copyright © 2015 Elsevier GmbH. All rights reserved.

Two critical periods in early visual cortex during figure-ground segregation.

PubMed

Wokke, Martijn E; Sligte, Ilja G; Steven Scholte, H; Lamme, Victor A F

2012-11-01

The ability to distinguish a figure from its background is crucial for visual perception. To date, it remains unresolved where and how in the visual system different stages of figure-ground segregation emerge. Neural correlates of figure border detection have consistently been found in early visual cortex (V1/V2). However, areas V1/V2 have also been frequently associated with later stages of figure-ground segregation (such as border ownership or surface segregation). To causally link activity in early visual cortex to different stages of figure-ground segregation, we briefly disrupted activity in areas V1/V2 at various moments in time using transcranial magnetic stimulation (TMS). Prior to stimulation we presented stimuli that made it possible to differentiate between figure border detection and surface segregation. We concurrently recorded electroencephalographic (EEG) signals to examine how neural correlates of figure-ground segregation were affected by TMS. Results show that disruption of V1/V2 in an early time window (96-119 msec) affected detection of figure stimuli and affected neural correlates of figure border detection, border ownership, and surface segregation. TMS applied in a relatively late time window (236-259 msec) selectively deteriorated performance associated with surface segregation. We conclude that areas V1/V2 are not only essential in an early stage of figure-ground segregation when figure borders are detected, but subsequently causally contribute to more sophisticated stages of figure-ground segregation such as surface segregation.

Two critical periods in early visual cortex during figure–ground segregation

PubMed Central

Wokke, Martijn E; Sligte, Ilja G; Steven Scholte, H; Lamme, Victor A F

2012-01-01

The ability to distinguish a figure from its background is crucial for visual perception. To date, it remains unresolved where and how in the visual system different stages of figure–ground segregation emerge. Neural correlates of figure border detection have consistently been found in early visual cortex (V1/V2). However, areas V1/V2 have also been frequently associated with later stages of figure–ground segregation (such as border ownership or surface segregation). To causally link activity in early visual cortex to different stages of figure–ground segregation, we briefly disrupted activity in areas V1/V2 at various moments in time using transcranial magnetic stimulation (TMS). Prior to stimulation we presented stimuli that made it possible to differentiate between figure border detection and surface segregation. We concurrently recorded electroencephalographic (EEG) signals to examine how neural correlates of figure–ground segregation were affected by TMS. Results show that disruption of V1/V2 in an early time window (96–119 msec) affected detection of figure stimuli and affected neural correlates of figure border detection, border ownership, and surface segregation. TMS applied in a relatively late time window (236–259 msec) selectively deteriorated performance associated with surface segregation. We conclude that areas V1/V2 are not only essential in an early stage of figure–ground segregation when figure borders are detected, but subsequently causally contribute to more sophisticated stages of figure–ground segregation such as surface segregation. PMID:23170239

The Effect of Aromatherapy Treatment on Fatigue and Relaxation for Mothers during the Early Puerperal Period in Japan: A Pilot Study.

PubMed

Asazawa, Kyoko; Kato, Yoshihiro; Yamaguchi, Atsuko; Inoue, Asako

2017-10-01

Early in the postpartum period, mothers are often nervous and tired from the delivery, breast-feeding and caring for a new-born. The aim of this study was to evaluate the process and outcome of using aromatherapy treatments to increase relaxation and decrease fatigue for mothers during the first to the seventh day of the postpartum period. This non-randomized controlled study with a quasi-experimental one-group pretest-posttest design was used to evaluate scores in relaxation and fatigue before and after the intervention. Aromatherapy hand treatments were performed on a purposive sample of 34 postpartum mothers in Tokyo, Japan, from May to July 2016. The single treatment included a choice of one of five essential aroma oils through hand and forearm massage. Relaxation and fatigue were measured by self-administered valid and reliable questionnaires. Wilcoxon signed-rank test was conducted to analyze the data before and after the intervention. The software programs SPSS, v. 23.0 (SPSS, Tokyo), was used to analyze the data, with the significance level set at 5%. Valid responses were obtained from 29 participants. A comparison of the scores before and after aroma treatment intervention indicated that the participants' relaxation scores increased significantly (P<0.001) and fatigue scores were significantly reduced (P<0.001). The majority of participants (77.8%) were satisfied with the treatment. The aroma treatments significantly improved relaxation and reduced fatigue for mothers in the early puerperal period and were well received. Therefore, a larger study using a pretest-posttest random control trial is recommended.

The Effect of Aromatherapy Treatment on Fatigue and Relaxation for Mothers during the Early Puerperal Period in Japan: A Pilot Study

PubMed Central

Asazawa, Kyoko; Kato, Yoshihiro; Yamaguchi, Atsuko; Inoue, Asako

2017-01-01

ABSTRACT Background: Early in the postpartum period, mothers are often nervous and tired from the delivery, breast-feeding and caring for a new-born. The aim of this study was to evaluate the process and outcome of using aromatherapy treatments to increase relaxation and decrease fatigue for mothers during the first to the seventh day of the postpartum period. Methods: This non-randomized controlled study with a quasi-experimental one-group pretest-posttest design was used to evaluate scores in relaxation and fatigue before and after the intervention. Aromatherapy hand treatments were performed on a purposive sample of 34 postpartum mothers in Tokyo, Japan, from May to July 2016. The single treatment included a choice of one of five essential aroma oils through hand and forearm massage. Relaxation and fatigue were measured by self-administered valid and reliable questionnaires. Wilcoxon signed-rank test was conducted to analyze the data before and after the intervention. The software programs SPSS, v. 23.0 (SPSS, Tokyo), was used to analyze the data, with the significance level set at 5%. Results: Valid responses were obtained from 29 participants. A comparison of the scores before and after aroma treatment intervention indicated that the participants’ relaxation scores increased significantly (P<0.001) and fatigue scores were significantly reduced (P<0.001). The majority of participants (77.8%) were satisfied with the treatment. Conclusion: The aroma treatments significantly improved relaxation and reduced fatigue for mothers in the early puerperal period and were well received. Therefore, a larger study using a pretest-posttest random control trial is recommended. PMID:29043282

Unbiased Proteomics of Early Lewy Body Formation Model Implicates Active Microtubule Affinity-Regulating Kinases (MARKs) in Synucleinopathies

PubMed Central

Riddle, Dawn M.; Zhang, Bin

2017-01-01

Parkinson's disease (PD) patients progressively accumulate intracytoplasmic inclusions formed by misfolded α-synuclein known as Lewy bodies (LBs). LBs also contain other proteins that may or may not be relevant in the disease process. To identify proteins involved early in LB formation, we performed proteomic analysis of insoluble proteins in a primary neuron culture model of α-synuclein pathology. We identified proteins previously found in authentic LBs in PD as well as several novel proteins, including the microtubule affinity-regulating kinase 1 (MARK1), one of the most enriched proteins in this model of LB formation. Activated MARK proteins (MARKs) accumulated in LB-like inclusions in this cell-based model as well as in a mouse model of LB disease and in LBs of postmortem synucleinopathy brains. Inhibition of MARKs dramatically exacerbated α-synuclein pathology. These findings implicate MARKs early in synucleinopathy pathogenesis and as potential therapeutic drug targets. SIGNIFICANCE STATEMENT Neurodegenerative diseases are diagnosed definitively only in postmortem brains by the presence of key misfolded and aggregated disease proteins, but cellular processes leading to accumulation of these proteins have not been well elucidated. Parkinson's disease (PD) patients accumulate misfolded α-synuclein in LBs, the diagnostic signatures of PD. Here, unbiased mass spectrometry was used to identify the microtubule affinity-regulating kinase family (MARKs) as activated and insoluble in a neuronal culture PD model. Aberrant activation of MARKs was also found in a PD mouse model and in postmortem PD brains. Further, inhibition of MARKs led to increased pathological α-synuclein burden. We conclude that MARKs play a role in PD pathogenesis. PMID:28522732

Biostratigraphy and biochronology of the Monte Hermoso Formation (early Pliocene) at its type locality, Buenos Aires Province, Argentina

NASA Astrophysics Data System (ADS)

Tomassini, Rodrigo L.; Montalvo, Claudia I.; Deschamps, Cecilia M.; Manera, Teresa

2013-12-01

The Monte Hermoso Formation, cropping out at its type locality of Farola Monte Hermoso (Buenos Aires Province), is a classical fossiliferous unit of the South American Neogene, highlighted by the abundance and diversity of its vertebrate remains. However, its biostratigraphy and age have been largely debated, and numerous discrepancies and controversies have been stated. In this regard, the result of the analysis of new materials recovered from the different levels of this formation, following a strict control of stratigraphic provenance, is here reported. As well, the provenance of specimens of previous collections has been evaluated. The studied assemblage consists of Osteichthyes, Amphibia, Reptilia, Aves and Mammalia. These latter are the most numerous and belong to the Didelphimorphia, Polydolopimorphia, Rodentia, Notoungulata, Litopterna and Xenarthra. The recorded taxa suggest no important faunistic variations among the different levels of the Monte Hermoso Formation that would imply significant chronological differences, and hence, justify the recognition of two biostratigraphic units. The analysis of the first and last records as well as the taxa considered as exclusive, does not support the validity of the biozones of Trigodon gaudryi and Neocavia depressidens previously proposed. On this basis, a new scheme for the Monte Hermoso Formation at its type locality is proposed, including a new single biostratigraphic unit. This unit is the Eumysops laeviplicatus Range Zone, which represents the biostratigraphic base for the Montehermosan Stage/Age of the early Pliocene.

Microgravity collisions of dust aggregates as an analogue to early planetesimal formation

NASA Astrophysics Data System (ADS)

Whizin, Akbar; Blum, Jürgen; Colwell, Joshua

2014-11-01

During the early stages of planet formation the dusty progenitors of planetesimals collided with each other continuously to form the seeds of planets. These collisions could result in growth or disruption depending on the individual impact velocities. Based on input from solar nebula models a laboratory-based microgravity dust collision experiment was developed for a drop tower at the Technische Universität Braunschweig, Germany. We collided 1.0 - 1.6 mm SiO2 dust aggregates with clusters of these aggregates at a range of velocities and mass ratios to determine the thresholds between bouncing, sticking, and fragmentation. Presented here are the results of 264 microgravity collisions occurring at velocities of 1 - 160 cm/s with target-impactor mass ratios of 5:1 to 400:1. We also present the coefficient of restitutions for low-velocity collisions and we find the specific collision energy of fragmentation Q* for aggregates of this size. We find sticking occurs at mass ratios larger than 40:1, but only for low velocities ≤ 3 cm/s, clear boundaries exist for bouncing up to 30 cm/s, and fragmentation at ~50 cm/s and up, with total disruption occurring above 1 m/s.

Effect of nanoporous TiO2 coating and anodized Ca2+ modification of titanium surfaces on early microbial biofilm formation

PubMed Central

2011-01-01

Background The soft tissue around dental implants forms a barrier between the oral environment and the peri-implant bone and a crucial factor for long-term success of therapy is development of a good abutment/soft-tissue seal. Sol-gel derived nanoporous TiO2 coatings have been shown to enhance soft-tissue attachment but their effect on adhesion and biofilm formation by oral bacteria is unknown. Methods We have investigated how the properties of surfaces that may be used on abutments: turned titanium, sol-gel nanoporous TiO2 coated surfaces and anodized Ca2+ modified surfaces, affect biofilm formation by two early colonizers of the oral cavity: Streptococcus sanguinis and Actinomyces naeslundii. The bacteria were detected using 16S rRNA fluorescence in situ hybridization together with confocal laser scanning microscopy. Results Interferometry and atomic force microscopy revealed all the surfaces to be smooth (Sa ≤ 0.22 μm). Incubation with a consortium of S. sanguinis and A. naeslundii showed no differences in adhesion between the surfaces over 2 hours. After 14 hours, the level of biofilm growth was low and again, no differences between the surfaces were seen. The presence of saliva increased the biofilm biovolume of S. sanguinis and A. naeslundii ten-fold compared to when saliva was absent and this was due to increased adhesion rather than biofilm growth. Conclusions Nano-topographical modification of smooth titanium surfaces had no effect on adhesion or early biofilm formation by S. sanguinis and A. naeslundii as compared to turned surfaces or those treated with anodic oxidation in the presence of Ca2+. The presence of saliva led to a significantly greater biofilm biovolume but no significant differences were seen between the test surfaces. These data thus suggest that modification with sol-gel derived nanoporous TiO2, which has been shown to improve osseointegration and soft-tissue healing in vivo, does not cause greater biofilm formation by the two oral

Effects of Earth's rotation on the early differentiation of a terrestrial magma ocean

NASA Astrophysics Data System (ADS)

Maas, Christian; Hansen, Ulrich

2015-11-01

Similar to other terrestrial planets like Moon and Mars, Earth experienced a magma ocean period about 4.5 billion years ago. On Earth differentiation processes in the magma ocean set the initial conditions for core formation and mantle evolution. During the magma ocean period Earth was rotating significantly faster than today. Further, the viscosity of the magma was low, thus that planetary rotation potentially played an important role for differentiation. However, nearly all previous studies neglect rotational effects. All in all, our results suggest that planetary rotation plays an important role for magma ocean crystallization. We employ a 3-D numerical model to study crystal settling in a rotating and vigorously convecting early magma ocean. We show that crystal settling in a terrestrial magma ocean is crucially affected by latitude as well as by rotational strength and crystal density. Due to rotation an inhomogeneous accumulation of crystals during magma ocean solidification with a distinct crystal settling between pole and equator could occur. One could speculate that this may have potentially strong effects on the magma ocean solidification time and the early mantle composition. It could support the development of a basal magma ocean and the formation of anomalies at the core-mantle boundary in the equatorial region, reaching back to the time of magma ocean solidification.

Adverse effects of meglumine diatrizoate on renal function in the early post-transplant period.

PubMed

Light, J A; Perloff, L J; Etheredge, E E; Hill, G; Spees, E K

1975-11-01

Thirty-four renal transplant recipients received drip infusion urograms from 2-24 days post-transplantation. Twenty-two patients exhibited changes in renal function within 1-4 days of the urogram that were indistinguishable from allograft rejection: a tender, swollen kidney, elevation of serum creatinine, oliguria, decreased urine sodium concentration, weight gain, and hypertension. Two patients developed acute tubular necrosis and required hemodialysis, but renal function in the remaining 20 patients improved after therapy for "graft rejection" with i.v. methyprednisolone sodium succinnate. Kidneys from older-age donors that were functioning suboptimally and kidneys which exhibited subsequent clinical allograft rejection were more at risk for contrast media toxicity. This suggests that occult vascular lesions may have been present in the allograft which were exacerbated when exposed to the irritant vascular effects of contrast media, producing a mild, reversible toxic nephritis. However, several kidneys with normal function and several kidneys which never exhibited rejection activity were also adversely affected by exposure to contrast media. It appears these agents should be used cautiously, if at all, in the early post-transplant period.

Petrology and diagenetic history of the upper shale member of the Late Devonian-Early Mississippian Bakken Formation, Williston Basin, North Dakota

USGS Publications Warehouse

Neil S. Fishman,; Sven O. Egenhoff,; Boehlke, Adam; Lowers, Heather A.

2015-01-01

The organic-rich upper shale member of the upper Devonian–lower Mississippian Bakken Formation (Williston Basin, North Dakota, USA) has undergone significant diagenetic alteration, irrespective of catagenesis related to hydrocarbon generation. Alteration includes precipitation of numerous cements, replacement of both detrital and authigenic minerals, multiple episodes of fracturing, and compaction. Quartz authigenesis occurred throughout much of the member, and is represented by multiple generations of microcrystalline quartz. Chalcedonic quartz fills radiolarian microfossils and is present in the matrix. Sulfide minerals include pyrite and sphalerite. Carbonate diagenesis is volumetrically minor and includes thin dolomite overgrowths and calcite cement. At least two generations of fractures are observed. Based on the authigenic minerals and their relative timing of formation, the evolution of pore waters can be postulated. Dolomite and calcite resulted from early postdepositional aerobic oxidation of some of the abundant organic material in the formation. Following aerobic oxidation, conditions became anoxic and sulfide minerals precipitated. Transformation of the originally opaline tests of radiolaria resulted in precipitation of quartz, and quartz authigenesis is most common in more distal parts of the depositional basin where radiolaria were abundant. Because quartz authigenesis is related to the distribution of radiolaria, there is a link between diagenesis and depositional environment. Furthermore, much of the diagenesis in the upper shale member preceded hydrocarbon generation, so early postdepositional processes were responsible for occlusion of significant original porosity in the member. Thus, diagenetic mineral precipitation was at least partly responsible for the limited ability of these mudstones to provide porosity for storage of hydrocarbons.

Formation and processing of organics in the early solar system.

PubMed

Kerridge, J F

1999-01-01

Until pristine samples can be returned from cometary nuclei, primitive meteorites represent our best source of information about organic chemistry in the early solar system. However, this material has been affected by secondary processing on asteroidal parent bodies which probably did not affect the material now present in cometary nuclei. Production of meteoritic organic matter apparently involved the following sequence of events: Molecule formation by a variety of reaction pathways in dense interstellar clouds; Condensation of those molecules onto refractory interstellar grains; Irradiation of organic-rich interstellar-grain mantles producing a range of molecular fragments and free radicals; Inclusion of those interstellar grains into the protosolar nebula with probable heating of at least some grain mantles during passage through the shock wave bounding the solar accretion disc; Agglomeration of residual interstellar grains and locally produced nebular condensates into asteroid-sized planetesimals; Heating of planetesimals by decay of extinct radionuclides; Melting of ice to produce liquid water within asteroidal bodies; Reaction of interstellar molecules, fragments and radicals with each other and with the aqueous environment, possibly catalysed by mineral grains; Loss of water and other volatiles to space yielding a partially hydrated lithology containing a complex suite of organic molecules; Heating of some of this organic matter to generate a kerogen-like complex; Mixing of heated and unheated material to yield the meteoritic material now observed. Properties of meteoritic organic matter believed to be consistent with this scenario include: Systematic decrease of abundance with increasing C number in homologous series of characterisable molecules; Complete structural diversity within homologous series; Predominance of branched-chain isomers; Considerable isotopic variability among characterisable molecules and within kerogen-like material; Substantial

The early cretaceous evolution of carbonate platforms from northern Oman

DOE Office of Scientific and Technical Information (OSTI.GOV)

Masse, J.P.; Borgomano, J.; Maskiry, S.Al.

1993-09-01

In northern Oman (Jebel Akhdar and foothills) Hauterivian to early Aptian shallow carbonate platforms are widely extending and pass laterally to slope and basin environments in the Nakhl zone. Progradational geometries are identified in that zone where significant correlation between thickness and sediment types supports a prominent tectonic control. The platform records four main sedimentary breaks (drowning events). Early Barremian (lower Lekhwair Formation), Late Barremian (basal Kharaib Formation), lowermost early Aptian (upper Kharaib Formation) and middle Aptian (Shuaiba-Al Hassanat formations boundary). The late Aptian-early Albian hiatus (pre-Nahr Umr unconformity) is regarded as an early Albian tectonically driven erosion. In themore » Nakhl zone, coral-rudist limestones of late Aptian-early Albian (lower Al Hassanat Formation) document an east-west ribbon platform, the southward extension of which was obscured by the middle Albian erosions and rudist limestones of middle to late Albian (upper Al Hassanat Formation), a lateral equivalent of the Nahr Umr circa littoral shaly sediments, document an east-west-trending linear platform. The foregoing points out a northward progradation coeval with a southward transgressive major trend for the Hauterivian-early Aptian interval, a faulted margin corresponding with the Nakhl zone active during the Aptian-Albian, a late Aptian ribbon platform coeval with the Bab basin initiation southward, a regional uplifting and truncation during the early-Albian (Austrian phase), whereas shallow-water carbonates are still forming at the edge of the former platform, and an active linear platform at the northern edge of the Nahr Umr basin, the corresponding drowning contemporaneous with the onset of the Cenomanian platform eastward.« less

Bacterial community dynamics during the early stages of biofilm formation in a chlorinated experimental drinking water distribution system: implications for drinking water discolouration.

PubMed

Douterelo, I; Sharpe, R; Boxall, J

2014-07-01

To characterize bacterial communities during the early stages of biofilm formation and their role in water discolouration in a fully representative, chlorinated, experimental drinking water distribution systems (DWDS). Biofilm development was monitored in an experimental DWDS over 28 days; subsequently the system was disturbed by raising hydraulic conditions to simulate pipe burst, cleaning or other system conditions. Biofilm cell cover was monitored by fluorescent microscopy and a fingerprinting technique used to assess changes in bacterial community. Selected samples were analysed by cloning and sequencing of the 16S rRNA gene. Fingerprinting analysis revealed significant changes in the bacterial community structure over time (P < 0·05). Cell coverage increased over time accompanied by an increase in bacterial richness and diversity. Shifts in the bacterial community structure were observed along with an increase in cell coverage, bacterial richness and diversity. Species related to Pseudomonas spp. and Janthinobacterium spp. dominated the process of initial attachment. Based on fingerprinting results, the hydraulic regimes did not affect the bacteriological composition of biofilms, but they did influence their mechanical stability. This study gives a better insight into the early stages of biofilm formation in DWDS and will contribute to the improvement of management strategies to control the formation of biofilms and the risk of discolouration. © 2014 The Authors. published by John Wiley & Sons Ltd on behalf of Society for Applied Microbiology.

Bacterial community dynamics during the early stages of biofilm formation in a chlorinated experimental drinking water distribution system: implications for drinking water discolouration

PubMed Central

Douterelo, I; Sharpe, R; Boxall, J

2014-01-01

Aims To characterize bacterial communities during the early stages of biofilm formation and their role in water discolouration in a fully representative, chlorinated, experimental drinking water distribution systems (DWDS). Methods and Results Biofilm development was monitored in an experimental DWDS over 28 days; subsequently the system was disturbed by raising hydraulic conditions to simulate pipe burst, cleaning or other system conditions. Biofilm cell cover was monitored by fluorescent microscopy and a fingerprinting technique used to assess changes in bacterial community. Selected samples were analysed by cloning and sequencing of the 16S rRNA gene. Fingerprinting analysis revealed significant changes in the bacterial community structure over time (P < 0·05). Cell coverage increased over time accompanied by an increase in bacterial richness and diversity. Conclusions Shifts in the bacterial community structure were observed along with an increase in cell coverage, bacterial richness and diversity. Species related to Pseudomonas spp. and Janthinobacterium spp. dominated the process of initial attachment. Based on fingerprinting results, the hydraulic regimes did not affect the bacteriological composition of biofilms, but they did influence their mechanical stability. Significance and Importance of the Study This study gives a better insight into the early stages of biofilm formation in DWDS and will contribute to the improvement of management strategies to control the formation of biofilms and the risk of discolouration. PMID:24712449

A novel method for reducing gap formation in tendon repair.

PubMed

Dean, Ryan; Sethi, Paul

2018-03-01

This study investigates gap formation in tendon repair using a novel tensioning method. The novel stitch will demonstrate less gap formation than the other suture configurations tested. Porcine tendons stitched with classic Krackow stitch configurations were compared to a Krackow stitch modified with a proximal Tension-Assist Loop. Each group was cyclically loaded followed by analysis of the tendon-suture construct for gap formation. The Tension-Assist Loop group produced significantly less gap formation than each of the other stitch groups. Decreasing early gap formation may be beneficial in allowing early rehabilitation and range of motion.

Characterizing the Early Impact Bombardment

NASA Technical Reports Server (NTRS)

Bogard, Donald D.

2005-01-01

The early bombardment revealed in the larger impact craters and basins on the moon was a major planetary process that affected all bodies in the inner solar system, including the Earth and Mars. Understanding the nature and timing of this bombardment is a fundamental planetary problem. The surface density of lunar impact craters within a given size range on a given lunar surface is a measure of the age of that surface relative to other lunar surfaces. When crater densities are combined with absolute radiometric ages determined on lunar rocks returned to Earth, the flux of large lunar impactors through time can be estimated. These studies suggest that the flux of impactors producing craters greater than 1 km in diameter has been approximately constant over the past approx. 3 Gyr. However, prior to 3.0 - 3.5 Gyr the impactor flux was much larger and defines an early bombardment period. Unfortunately, no lunar surface feature older than approx. 4 Gyr is accurately dated, and the surface density of craters are saturated in most of the lunar highlands. This means that such data cannot define the impactor flux between lunar formation and approx. 4 Gyr ago.

The Earth's magnetic field in Italy during the Neolithic period: New data from the Early Neolithic site of Portonovo (Marche, Italy)

NASA Astrophysics Data System (ADS)

Tema, Evdokia; Ferrara, Enzo; Camps, Pierre; Conati Barbaro, Cecilia; Spatafora, Simone; Carvallo, Claire; Poidras, Thierry

2016-08-01

We present new, full geomagnetic field vector results from three Neolithic ovens discovered at the archaeological site of Portonovo (Marche, Italy). The discovered structures are a rare example of very well preserved underground ovens from the Early Neolithic period. Standard thermal demagnetization procedures were used to isolate the direction of the Characteristic Remanent Magnetization acquired by the baked clay during the ovens' last firing. The corresponding archaeointensities were determined by the multi-specimen procedure (MSP-DSC) and show a clear intensity low during the Neolithic period. Both directional and intensity results are of high quality, offering the first contribution of full geomagnetic field vector data for this period in Italy. The new data are compared with other contemporaneous data from Europe and with global geomagnetic field models. Independent archaeomagnetic dating of the three ovens was also performed by means of the SCHA.DIF.14k model. The obtained results are in excellent agreement with available radiocarbon dates and confirm that all ovens belong to the Neolithic. These new data importantly enrich our knowledge of the geomagnetic field during the Neolithic period that is poorly documented by data, not only in Italy but also in the whole of Europe and show that archaeomagnetic dating can provide precise results even for prehistoric periods.

The formation of jupiter, the jovian early bombardment and the delivery of water to the asteroid belt: the case of (4) vesta.

PubMed

Turrini, Diego; Svetsov, Vladimir

2014-01-28

The asteroid (4) Vesta, parent body of the Howardite-Eucrite-Diogenite meteorites, is one of the first bodies that formed, mostly from volatile-depleted material, in the Solar System. The Dawn mission recently provided evidence that hydrated material was delivered to Vesta, possibly in a continuous way, over the last 4 Ga, while the study of the eucritic meteorites revealed a few samples that crystallized in presence of water and volatile elements. The formation of Jupiter and probably its migration occurred in the period when eucrites crystallized, and triggered a phase of bombardment that caused icy planetesimals to cross the asteroid belt. In this work, we study the flux of icy planetesimals on Vesta during the Jovian Early Bombardment and, using hydrodynamic simulations, the outcome of their collisions with the asteroid. We explore how the migration of the giant planet would affect the delivery of water and volatile materials to the asteroid and we discuss our results in the context of the geophysical and collisional evolution of Vesta. In particular, we argue that the observational data are best reproduced if the bulk of the impactors was represented by 1-2 km wide planetesimals and if Jupiter underwent a limited (a fraction of au) displacement.

The Formation of Jupiter, the Jovian Early Bombardment and the Delivery of Water to the Asteroid Belt: The Case of (4) Vesta

PubMed Central

Turrini, Diego; Svetsov, Vladimir

2014-01-01

The asteroid (4) Vesta, parent body of the Howardite-Eucrite-Diogenite meteorites, is one of the first bodies that formed, mostly from volatile-depleted material, in the Solar System. The Dawn mission recently provided evidence that hydrated material was delivered to Vesta, possibly in a continuous way, over the last 4 Ga, while the study of the eucritic meteorites revealed a few samples that crystallized in presence of water and volatile elements. The formation of Jupiter and probably its migration occurred in the period when eucrites crystallized, and triggered a phase of bombardment that caused icy planetesimals to cross the asteroid belt. In this work, we study the flux of icy planetesimals on Vesta during the Jovian Early Bombardment and, using hydrodynamic simulations, the outcome of their collisions with the asteroid. We explore how the migration of the giant planet would affect the delivery of water and volatile materials to the asteroid and we discuss our results in the context of the geophysical and collisional evolution of Vesta. In particular, we argue that the observational data are best reproduced if the bulk of the impactors was represented by 1–2 km wide planetesimals and if Jupiter underwent a limited (a fraction of au) displacement. PMID:25370027

Concurrent formation of supermassive stars and globular clusters: implications for early self-enrichment

NASA Astrophysics Data System (ADS)

Gieles, Mark; Charbonnel, Corinne; Krause, Martin G. H.; Hénault-Brunet, Vincent; Agertz, Oscar; Lamers, Henny J. G. L. M.; Bastian, Nathan; Gualandris, Alessia; Zocchi, Alice; Petts, James A.

2018-04-01

We present a model for the concurrent formation of globular clusters (GCs) and supermassive stars (SMSs, ≳ 103 M⊙) to address the origin of the HeCNONaMgAl abundance anomalies in GCs. GCs form in converging gas flows and accumulate low-angular momentum gas, which accretes onto protostars. This leads to an adiabatic contraction of the cluster and an increase of the stellar collision rate. A SMS can form via runaway collisions if the cluster reaches sufficiently high density before two-body relaxation halts the contraction. This condition is met if the number of stars ≳ 106 and the gas accretion rate ≳ 105 M⊙/Myr, reminiscent of GC formation in high gas-density environments, such as - but not restricted to - the early Universe. The strong SMS wind mixes with the inflowing pristine gas, such that the protostars accrete diluted hot-hydrogen burning yields of the SMS. Because of continuous rejuvenation, the amount of processed material liberated by the SMS can be an order of magnitude higher than its maximum mass. This `conveyor-belt' production of hot-hydrogen burning products provides a solution to the mass budget problem that plagues other scenarios. Additionally, the liberated material is mildly enriched in helium and relatively rich in other hot-hydrogen burning products, in agreement with abundances of GCs today. Finally, we find a super-linear scaling between the amount of processed material and cluster mass, providing an explanation for the observed increase of the fraction of processed material with GC mass. We discuss open questions of this new GC enrichment scenario and propose observational tests.

Mars’ Growth Stunted by an Early Giant Planet Instability

NASA Astrophysics Data System (ADS)

Clement, Matthew; Kaib, Nathan A.; Raymond, Sean N.; Walsh, Kevin J.

2017-10-01

Many dynamical aspects of the solar system can be explained by the outer planets experiencing a period of orbital instability. Though often correlated with a perceived delayed spike in the lunar cratering record known as the Late Heavy Bombardment (LHB), recent work suggests that this event may have occurred during the epoch of terrestrial planet formation. Though current simulations of terrestrial accretion can reproduce many observed qualities of the solar system, replicating the small mass of Mars requires modification to standard planet formation models. Here we use direct numerical simulations to show that an early instability in the outer solar system regularly yields properly sized Mars analogues. In 80% of simulations, we produce a Mars of the appropriate mass. Our most successful outcomes occur when the terrestrial planets evolve 10 million years (Myr), and accrete several Mars sized embryos in the Mars forming region before the instability takes place. Mars is left behind as a stranded embryo, while the remainder of these bodies are either ejected from the system or scattered towards the inner solar system where they deliver water to Earth. An early giant planet instability can thus replicate both the inner and outer solar system in a single model.

In situ probing of pulsed laser melting and laser-induced periodic surface structures formation by dynamic reflectivity

NASA Astrophysics Data System (ADS)

Huynh, T. T. D.; Semmar, N.

2017-09-01

The melting process and nanostructure formation induced by nanosecond and picosecond laser pulses on bulk silicon and copper thin film were studied by ex situ analysis and in situ real time reflectivity. Three different probing wavelengths (633, 473 and 326 nm) were used during the pump laser processing and were correlated to the beam parameters (pulse duration, laser fluence and number of laser shots) and copper thin film thickness. On a silicon surface using a KrF laser beam (27 ns, 1 Hz, 248 nm), the melting threshold was determined close to 700 mJ cm-2 and the melting duration increased from 10 to 130 ns as the fluence increased from 700 to 1750 mJ cm-2. Nanostructures with a spatial period close to the laser wavelength were formed on both copper thin film and silicon substrate after nanosecond Nd:YAG laser (10 ns, 266 nm, 1 Hz) irradiation. In the picosecond regime, using an Nd:YAG laser (40 ps, 266 nm, 1 Hz), different nanostructures, from spikes to laser-induced periodic surface structures, were formed on 500 nm copper thin film and were analyzed with respect to the drop in dynamic reflectivity changes versus the number of laser shots.

Migration as a turning point in food habits: the early phase of dietary acculturation among women from South Asian, African, and Middle Eastern Countries living in Norway.

PubMed

Terragni, Laura; Garnweidner, Lisa M; Pettersen, Kjell Sverre; Mosdøl, Annhild

2014-01-01

This article explores the early phase of dietary acculturation after migration. South Asian, African and Middle Eastern women (N = 21) living in Norway were interviewed about their early experiences with food in a new context. The findings pointed to abrupt changes in food habits in the first period after migration. To various degrees, women reported unfamiliarity with foods in shops, uncertainty about meal formats and food preparation and fear of eating food prohibited by their religion. Their food consumption tended to be restricted to food items perceived as familiar or safe. Our findings indicate that the first period after migration represents a specific phase in the process of dietary acculturation. Early initiatives aimed at enhancing confidence in food and familiarity with the new food culture are recommended.

[Clinical efficiency of Vasonat in neurometabolic therapy of patients with ischemic stroke at early rehabilitation period].

PubMed

Abasova, G B; Tyksanbaeva, G U; Orazalieva, D B; Kasymova, S K

2011-01-01

Research of efficiency and safety of Vasonat has been carried out. 31 patients aged 46-75 years who had had hemispheric athero- thrombotic or hemodynamic schemic stroke with moderate severity and being treated in 2-5-month of early rehabilitation period have been observed. The control group of patients received placebo. Results of the study, 4 weeks treatment using Vasonat in the dosage of 500 mg/day have shown positive effect on common signs of the disease by decreasing headache intensity, dizziness, a nausea, and on focal neurological symptoms by decreasing hemiparesis degree; psychoemotional and mnestic activity (main memory and attention) improved as well. It was more distinct in patients with localization of the stroke in the right hemisphere of the brain. It was also noted more rapid improvement of motion function and quality of life of patients.

EFFECTS OF LASER RADIATION ON MATTER: Efficient surface-erosion plasma formation in air due to the action of pulse-periodic laser radiation

NASA Astrophysics Data System (ADS)

Min'ko, L. Ya; Chumakou, A. N.; Bosak, N. A.

1990-11-01

A study was made of the interaction of a series of periodic laser (λ = 1.06 μm) pulses with a number of materials (aluminum, copper, graphite, ebonite) in air at laser radiation power densities q = 107-109 W/cm2 and repetition frequencies f<=50 kHz. The radiation was concentrated in spots of ~ 10 - 2 cm2 area. Efficient formation of plasma as a result of laser erosion (q > 2 × 108 W/cm2, f>=5 kHz) was observed. A screening layer of an air plasma created by the first pulse of the series was expelled from the interaction zone and this was followed by erosion plasma formation under conditions of slight screening of the target during the action of the subsequent laser pulses.

Formation of an 18R long-period stacking ordered structure in rapidly solidified Mg{sub 88}Y{sub 8}Zn{sub 4} alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garcés, Gerardo, E-mail: ggarces@cenim.csic.es

The formation of the long-period stacking ordered structure (LPSO) in a Mg{sub 88}Y{sub 8}Zn{sub 4}(at%) ribbon produced by melt spinning was studied using high energy X-ray synchrotron radiation diffraction during in-situ isochronal heating and transmission electron microscopy. The microstructure of the rapidly solidified ribbons is characterised by fine magnesium grains with yttrium and zinc in solid solution and primary 18R LPSO-phase segregated at grain boundaries. Using differential scanning calorimetry, a strong exothermal peak was observed around 300 °C which was associated with the development of the 18R-type LPSO-phase in the magnesium grains. The apparent activation energy calculated using the Kissingermore » model was 125 KJmol{sup −1} and it is related to simultaneous diffusion of Y and Zn through magnesium basal plane. - Highlights: •The formation of the LPSO phase in rapidly solidified ribbons was studied. •The formation of the 18R LPSO starts at around 300 °C. •LPSO formation have to steps: Stacking faults along basal plane and then growth of 18R structure along the c direction.« less

Trajectories of fathers' psychological distress across the early parenting period: Implications for parenting.

PubMed

Giallo, Rebecca; Cooklin, Amanda; Brown, Stephanie; Christensen, Daniel; Kingston, Dawn; Liu, Cindy H; Wade, Catherine; Nicholson, Jan M

2015-10-01

Fathers' parenting behavior is a likely key mechanism underlying the consistent associations between paternal mental health difficulties and poor emotional-behavioral outcomes for children. This study investigates the association between fathers' mental health trajectories and key parenting behaviors (warmth, hostility, consistency) spanning the first 8-9 years postpartum. Secondary analyses of 5 waves of data from 2,662 fathers participating in the Longitudinal Study of Australian Children were conducted. Latent growth class analysis was used to identify distinct trajectories of fathers' distress (Kessler-6; Kessler et al., 2003), and latent growth models estimated parenting warmth, hostility, and consistency. Multiple group analyses were conducted to describe and compare the course of parenting behaviors for fathers assigned to the distress trajectories identified. Two distinct classes of fathers were identified based on the trajectories of distress: minimal distress (92%) and persistent and increasing distress (8%). The latter group reported significantly lower parenting warmth when their children were 8-9 years and lower consistency and higher hostility across all study intervals. The postnatal and early parenting period is a critical time for the development of parenting behaviors that are important for children's development. Engagement and support for fathers around well-being and parenting is vital for promoting optimal family and child developmental outcomes. (c) 2015 APA, all rights reserved).

Accelerated Implantable Defibrillator Battery Depletion Secondary to Lithium Cluster Formation: A Case Series.

PubMed

Aggarwal, Ashim; Sarmiento, Joseph J; Charles, David R; Parr, Alan R; Baman, Timir S

2016-04-01

Device failure from unanticipated and precipitous battery depletion is uncommon but can be life-threatening. Multiple mechanisms of battery failure have been previously described in the medical literature. However, in this current case series, we describe the largest cohort of patients (n = 4) with St. Jude (St. Paul, MN, USA) early implantable defibrillator battery depletion attributable to lithium cluster formation causing short circuit and high current drain. Clinicians must be aware of this occult cause of device failure and more studies are needed to determine its true prevalence. © 2015 Wiley Periodicals, Inc.

Floods of the Maros river in the early modern and modern period (16th-20th centuries)

NASA Astrophysics Data System (ADS)

Kiss, Andrea

2016-04-01

In the poster presentation a series of historical and recent floods of the Maros river, with special emphasis on the flood events occurred on the lower sections, are presented. Similar to the Hungarian flood databases of the Middle-Danube and Lower-Tisza, the main sources of investigations are the institutional (legal-administrative) documentary evidence (e.g. Szeged and Makó town council protocols and related administrative documentation, Csanád County meeting protocols) mainly from the late 17th-early 18th century onwards. However, in case of the Maros river there is an increased importance of narrative sources, with special emphasis on the early modern period (16th-17th century): in this case the (mainly Transylvanian) narratives (chronicles, diaries, memoires etc.) written by aristocrats, other noblemen and town citizens have particular importance. In the presentation the frequency of detected flood events, from the mid-16th century onwards (with an outlook on sporadic medieval evidence), is provided; moreover, a 3-scaled magnitude classification and a seasonality analysis are also presented. Floods of the Maros river, especially those of the lower river sections, often cannot be understood and discussed without the floods of the (Lower-)Tisza; thus, a comparison of the two flood series are also a subject of discussion. Unlike the Lower-Tisza, the Maros is prone to winter and early spring ice jam floods: since the floods that belonged to this type (similar to those of the Middle-Danube at Budapest) were the most destructive among the flood events of the river, this flood type, and the greatest flood events (e.g. 1751-1752, 1784) are also presented in more detail.

Individual differences in early adolescents' latent trait cortisol (LTC): Relation to early adversity.

PubMed

Stroud, Catherine B; Chen, Frances R; Doane, Leah D; Granger, Douglas A

2016-09-01

Substantial evidence suggests that youth who experience early adversity exhibit alterations in hypothalamic pituitary adrenal (HPA) axis functioning, thereby increasing risk for negative health outcomes. However, few studies have explored whether early adversity alters enduring trait indicators of HPA axis activity. Using objective contextual stress interviews with adolescents and their mothers to assess early adversity, we examined the cumulative impact of nine types of early adversity on early adolescents girls' latent trait cortisol (LTC). Adolescents (n = 122; M age = 12.39 years) provided salivary cortisol samples three times a day (waking, 30 min post-waking, and bedtime) over 3 days. Latent state-trait modeling indicated that the waking and 30 min post-waking samples contributed to a LTC factor. Moreover, greater early adversity was associated with a lower LTC level. Implications of LTC for future research examining the impact of early adversity on HPA axis functioning are discussed. © 2016 Wiley Periodicals, Inc. Dev Psychobiol 58:700-713, 2016. © 2016 Wiley Periodicals, Inc.

AWBAT: early clinical experience.

PubMed

Vandenberg, Victoria B

2010-03-15

The purpose of this article is to describe the early clinical experience with AWBAT. Burn patients requiring (1) donor sites or (2) treatment of a superficial burn wound injury were treated. A total of 45 patients with 69 distinct wounds were included. AWBAT-D was evaluated in donor sites and AWBAT-S was evaluated in superficial partial-thickness burns. Days to healing, pain, hematoma/seroma formation, and infection were noted. Ease of application, adherence, transparency, and physical adaptability details were collected. Average period to healing of donor sites treated with AWBAT-D (n=22 patients with n=26 wounds) was 11.2 days, sigma =1.95, with a range of 8-15 days and a median of 11 days. Pain rating at 24 hours was 1.2, sigma =0.43 (n=18) and at 48 hours mean was 1.2, sigma =0.46 (n=15). Average period to healing of superficial burns treated with AWBAT-S (n=15 patients with n=18 wounds) was 8.1 days, sigma =2.48, with a range of 5-13 days and a median of 7 days. Pain rating at 24 hours was 1.5, sigma =0.85 (n=10) and at 48 hours mean was 1.75, sigma =0.89 (n=8). There was zero incidence of hematoma/seroma. No infections were seen. Results indicate that AWBAT was easily applied with good initial adherence. It was noted to be transparent, conformant, and pliable. Early experience demonstrates that AWBAT performs well on donor sites and superficial partial-thickness burns and delivers the desired attributes of a temporary skin substitute including good adherence, infection control, transparency, adapatability, and pain control.

Laminarin improves developmental competence of porcine early stage embryos by inhibiting oxidative stress.

PubMed

Jiang, Hao; Liang, Shuang; Yao, Xue-Rui; Jin, Yong-Xun; Shen, Xing-Hui; Yuan, Bao; Zhang, Jia-Bao; Kim, Nam-Hyung

2018-04-23

Laminarin (LMA), a β-glucan mixture with good biocompatibility, improves the growth performance and immune response when used as food additives and nutraceuticals. The aim of the present research was to explore the effects of LMA on porcine early stage embryo development, as well as the underlying mechanisms. The results showed that the developmental competence of porcine early stage embryos was dramatically improved after LMA supplementation during the in vitro culture period. The presence of 20 μg/mL LMA during the in vitro culture period significantly improved cleavage rate, blastocyst formation rates, hatching rate, and total cell number in the blastocyst compared to that in the control group. Notably, LMA attenuated the intracellular reactive oxygen species generation induced by H 2 O 2 . Furthermore, LMA not only increased intracellular glutathione levels, but also ameliorated mitochondrial membrane potential. In addition, the expression of a zygotic genome activation related gene (YAP1), pluripotency-related genes (OCT4, NANOG, and SOX2), and hatching-related genes (COX2, GATA4, and ITGA5) were up-regulated following LMA supplementation during porcine early stage embryo development. These results demonstrate that LMA has beneficial effects on the development of porcine early stage embryos via regulation of oxidative stress. This evidence provides a novel method for embryo development improvement associated with exposure to LMA. Copyright © 2018 Elsevier Inc. All rights reserved.

A Basal Sauropodomorph (Dinosauria: Saurischia) from the Ischigualasto Formation (Triassic, Carnian) and the Early Evolution of Sauropodomorpha

PubMed Central

Martinez, Ricardo N.; Alcober, Oscar A.

2009-01-01

Background The earliest dinosaurs are from the early Late Triassic (Carnian) of South America. By the Carnian the main clades Saurischia and Ornithischia were already established, and the presence of the most primitive known sauropodomorph Saturnalia suggests also that Saurischia had already diverged into Theropoda and Sauropodomorpha. Knowledge of Carnian sauropodomorphs has been restricted to this single species. Methodology/Principal Findings We describe a new small sauropodomorph dinosaur from the Ischigualsto Formation (Carnian) in northwest Argentina, Panphagia protos gen. et sp. nov., on the basis of a partial skeleton. The genus and species are characterized by an anteroposteriorly elongated fossa on the base of the anteroventral process of the nasal; wide lateral flange on the quadrate with a large foramen; deep groove on the lateral surface of the lower jaw surrounded by prominent dorsal and ventral ridges; bifurcated posteroventral process of the dentary; long retroarticular process transversally wider than the articular area for the quadrate; oval scars on the lateral surface of the posterior border of the centra of cervical vertebrae; distinct prominences on the neural arc of the anterior cervical vertebra; distal end of the scapular blade nearly three times wider than the neck; scapular blade with an expanded posterodistal corner; and medial lamina of brevis fossa twice as wide as the iliac spine. Conclusions/Significance We regard Panphagia as the most basal sauropodomorph, which shares the following apomorphies with Saturnalia and more derived sauropodomorphs: basally constricted crowns; lanceolate crowns; teeth of the anterior quarter of the dentary higher than the others; and short posterolateral flange of distal tibia. The presence of Panphagia at the base of the early Carnian Ischigualasto Formation suggests an earlier origin of Sauropodomorpha during the Middle Triassic. PMID:19209223

Coating transformations in the early stages of hot-dip galvannealing of steel sheet

NASA Astrophysics Data System (ADS)

McDevitt, Erin Todd

The present, comprehensive study of the reactions occurring early in galvanneal processing under conditions typical of commercial production represents the first detailed investigation of the microstructural evolution of the coating in the early stages of galvannealing and the results shed new light on the course of the coating microstructural development. During hot dipping, an Fe2Al5 inhibition layer formed on the surface of the steel substrate in the first instants of immersion in Zn baths containing as low as 0.10 wt.% Al. When hot-dipping in a 0.14 wt.% Al, the as-dipped coating microstructure consisted of an Fe2Al 5 layer on the steel surface. That layer was covered by a layer of the Fe-Zn compound Gamma1, which was covered by the zeta phase or unalloyed Zn. Substrate chemistry did not affect coating microstructure development in the bath. Thermodynamic predictions of the precipitation behavior during the bath reactions agrees well with experimental observations. A mechanism for coating microstructure development in the Zn bath which is consistent with all the experimental results is proposed. From this information, the metallurgical variables which govern inhibition layer formation are discerned. The breakdown of the Fe2Al5 inhibition layer during galvannealing at 500°C occurred without the formation of outbursts. Instead, the grain boundary diffusion of Al into the steel substrate accounted for dissolution of the inhibition layer in the first second of galvannealing. A mechanism for inhibition layer breakdown is presented. P-additions affected only the rate at which the inhibition layer dissolved and did not affect the rate of Fe-Zn compound formation. P in the substrate blocked grain boundary diffusion of Al into the substrate thus slowing inhibition layer dissolution. The slower overall galvannealing behavior often observed on P-bearing substrates is due to a longer period of inhibition layer survival which results in a longer incubation period for the

Nearest pattern interaction and global pattern formation

NASA Astrophysics Data System (ADS)

Jeong, Seong-Ok; Moon, Hie-Tae; Ko, Tae-Wook

2000-12-01

We studied the effect of nearest pattern interaction on a global pattern formation in a two-dimensional space, where patterns are to grow initially from a noise in the presence of a periodic supply of energy. Although our approach is general, we found that this study is relevant in particular to the pattern formation on a periodically vibrated granular layer, as it gives a unified perspective of the experimentally observed pattern dynamics such as oscillon and stripe formations, skew-varicose and crossroll instabilities, and also a kink formation and decoration.

On the inscription of period and half-period surface relief gratings in azobenzene-functionalized polymers.

PubMed

Sobolewska, Anna; Miniewicz, Andrzej

2008-04-17

Laser-light-induced surface relief grating inscription was carried out in the newly synthesized azobenzene-functionalized poly(amide-imide)s having the same main- and side-chain structures but different substituents in the azobenzene groups. The gratings were inscribed employing the two-wave mixing technique with linearly polarized laser beams. Three different polarization configurations were used: s-s, p-p, and s-p. The relatively deep surface relief gratings of period Lambda were formed for the case of s-s and p-p polarizations, whereas the s-p inscription resulted in the half-period grating (Lambda/2) with the weak surface modulation. The origin of the formation of Lambda/2 structure for s-p configuration results from the interference between zeroth- and first-order beams scattered on the polarization refractive index grating and having the same polarization. On the basis of this idea, we presented the simple kinetic model predicting and modeling the half-period grating formation with its temporal evolution. The proposed model is consistent with the experimental findings.

Short communication: Effect of heat stress on markers of autophagy in the mammary gland during the dry period.

PubMed

Wohlgemuth, S E; Ramirez-Lee, Y; Tao, S; Monteiro, A P A; Ahmed, B M; Dahl, G E

2016-06-01

Heat stress (HT) during the dry period compromises mammary gland (MG) growth, thus negatively affecting subsequent milk yield. Cooling during the late dry period, when mammary tissue proliferates, is a common management practice. However, it neglects MG involution during the early dry period, a process that is accomplished by both apoptosis and autophagy. Our objective was to evaluate the effect of HT on MG autophagy during the early dry period. Holstein cows were dried off ~45d before expected calving and randomly assigned to 1 of 2 treatments: HT or cooling (CL). All cows were housed in the same free stall barn during the dry period, but only the stall area for CL cows was equipped with soakers and fans. Rectal temperature and respiration rate were measured daily during the dry period. Mammary gland biopsies were collected from each cow 3d before dry-off and on d 3, 7, 14, and 22±2 after dry-off. Autophagy in the MG was determined by measuring protein expression of 2 autophagic markers, autophagy-related protein 7 and microtubule-associated protein light chain 3 (LC3). The average temperature-humidity index during the dry period was 77.7, which indicated that HT and CL cows were exposed to significant heat stress. However, the cooling system effectively alleviated heat strain in CL cows by decreasing the rectal temperature (39.0 vs. 39.4°C) and respiration rate (47.3 vs. 71.2 breaths per minute) relative to HT cows. Protein expression of autophagy-related protein 7, a marker for early autophagosome formation, did not change within or between groups. In contrast, protein expression of LC3-II, a marker of autophagosomes, and its precursor LC3-I showed a dynamic expression pattern in MG from CL cows during the early dry period. Relative to HT cows, MG from CL cows displayed higher expression of LC3-I and LC3-II on d 7 and lower expression of LC3-II on d 14 and 22 after dry-off. Collectively, our data provide a possible mechanistic explanation for the impairment of

Some Reflections on the Periodic Table and Its Use.

ERIC Educational Resources Information Center

Fernelius, W. Conard

1986-01-01

Discusses early periodic tables; effect on the periodic table of atomic numbers; the periodic table in relation to electron distribution in the atoms of elements; terms and concepts related to the table; and the modern basis of the periodic table. Additional comments about these and other topics are included. (JN)

Planet Formation

NASA Astrophysics Data System (ADS)

Klahr, Hubert; Brandner, Wolfgang

2011-02-01

1. Historical notes on planet formation Bodenheimer; 2. The formation and evolution of planetary systems Bouwman et al.; 3. Destruction of protoplanetary disks by photoevaporation Richling, Hollenbach and Yorke; 4. Turbulence in protoplanetary accretion disks Klahr, Rozyczka, Dziourkevitch, Wunsch and Johansen; 5. The origin of solids in the early solar system Trieloff and Palme; 6. Experiments on planetesimal formation Wurm and Blum; 7. Dust coagulation in protoplanetary disks Henning, Dullemond, Wolf and Dominik; 8. The accretion of giant planet cores Thommes and Duncan; 9. Planetary transits: direct vision of extrasolar planets Lecavelier des Etangs and Vidal-Madjar; 10. The core accretion - gas capture model Hubickyj; 11. Properties of exoplanets Marcy, Fischer, Butler and Vogt; 12. Giant planet formation: theories meet observations Boss; 13. From hot Jupiters to hot Neptures … and below Lovis, Mayor and Udry; 14. Disk-planet interaction and migration Masset and Kley; 15. The Brown Dwarf - planet relation Bate; 16. From astronomy to astrobiology Brandner; 17. Overview and prospective Lin.

Integrated loessite-paleokarst depositional system, early Pennsylvanian Molas Formation, Paradox Basin, southwestern Colorado, U.S.A.

NASA Astrophysics Data System (ADS)

Evans, James E.; Reed, Jason M.

2007-03-01

Mississippian paleokarst served as a dust trap for the oldest known Paleozoic loessite in North America. The early Pennsylvanian Molas Formation consists of loessite facies (sorted, angular, coarse-grained quartz siltstone), infiltration facies (loess redeposited as cave sediments within paleokarst features of the underlying Mississippian Leadville Limestone), colluvium facies (loess infiltrated into colluvium surrounding paleokarst towers) and fluvial facies (siltstone-rich, fluvial channel and floodplain deposits with paleosols). The depositional system evolved from an initial phase of infiltration and colluvium facies that were spatially and temporally related to the paleokarst surface, to loessite facies that mantled the paleotopography, and to fluvial facies that were intercalated with marine-deltaic rocks of the overlying Pennsylvanian Hermosa Formation. This sequence is interpreted as a response to the modification of the dust-trapping ability of the paleokarst surface. Loess was initially eroded from the surface, transported and redeposited in the subsurface by the karst paleohydrologic system, maintaining the dust-trapping ability of the paleotopographic surface. Later, the paleotopographic surface was buried when loess accumulation rates exceeded the transport capacity of the karst paleohydrologic system. These changes could have occurred because of (1) increased dust input rates in western Pangaea, (2) rising base levels and/or (3) porosity loss due to deposition within paleokarst passageways.

System and method for implementing periodic early discard in on-chip buffer memories of network elements

DOEpatents

Francini, Andrea

2013-05-14

An advance is made over the prior art in accordance with the principles of the present invention that is directed to a new approach for a system and method for a buffer management scheme called Periodic Early Discard (PED). The invention builds on the observation that, in presence of TCP traffic, the length of a queue can be stabilized by selection of an appropriate frequency for packet dropping. For any combination of number of TCP connections and distribution of the respective RTT values, there exists an ideal packet drop frequency that prevents the queue from over-flowing or under-flowing. While the value of the ideal packet drop frequency may quickly change over time and is sensitive to the series of TCP connections affected by past packet losses, and most of all is impossible to compute inline, it is possible to approximate it with a margin of error that allows keeping the queue occupancy within a pre-defined range for extended periods of time. The PED scheme aims at tracking the (unknown) ideal packet drop frequency, adjusting the approximated value based on the evolution of the queue occupancy, with corrections of the approximated packet drop frequency that occur at a timescale that is comparable to the aggregate time constant of the set of TCP connections that traverse the queue.

The hyper-enrichment of V and Zn in black shales of the Late Devonian-Early Mississippian Bakken Formation (USA)

USGS Publications Warehouse

Scott, Clinton T.; Slack, John F.; Kelley, Karen Duttweiler

2017-01-01

Black shales of the Late Devonian to Early Mississippian Bakken Formation are characterized by high concentrations of organic carbon and the hyper-enrichment (> 500 to 1000s of mg/kg) of V and Zn. Deposition of black shales resulted from shallow seafloor depths that promoted rapid development of euxinic conditions. Vanadium hyper-enrichments, which are unknown in modern environments, are likely the result of very high levels of dissolved H2S (~ 10 mM) in bottom waters or sediments. Because modern hyper-enrichments of Zn are documented only in Framvaren Fjord (Norway), it is likely that the biogeochemical trigger responsible for Zn hyper-enrichment in Framvaren Fjord was also present in the Bakken basin. With Framvaren Fjord as an analogue, we propose a causal link between the activity of phototrophic sulfide oxidizing bacteria, related to the development of photic-zone euxinia, and the hyper-enrichment of Zn in black shales of the Bakken Formation.

[VIABILITY OF MYOCAROIUM AS RISK FACTOR FOR MORTALITY IN EARLY AND LATE PERIOD AFTER BYPASS SURGERY OF CORONARY ARTERIES IN PATIENTS WITH CORONARY HEART DISEASE AND SEVERE LEFT VENTRICULAR DYSFUNCTION].

PubMed

Todurov, B M; Zelenchuk, V; Kuzmich, I M; Ivanyuk, N B; Nikolaichuk, M V

2015-06-01

In coronary heart disease and low ejection fraction of the left ventricle (LV) in patients after coronary artery bypass surgery tend mortality and complication rate higher than preserved LV systolic function. Significant preoperative predictors of early mortality and remote in these patients, and the incidence of complications in the early postoperative period were reveald.

Quasi-Periodic Long-Term Quadrature Light Variability in Early Type Interacting Binary Systems

NASA Astrophysics Data System (ADS)

Peters, Geraldine Joan

2015-08-01

Four years of Kepler observations have revealed a class of Algol-type binaries in which the relative brightness of the quadrature light varies from > 1 to <1 on a time scale of about 100-400 days. The behavior pattern is quasi-periodic. We call these systems L/T (leading hemisphere/ trailing hemisphere) variables. Although L/T inequality in eclipsing binaries has been noted from ground-based photometry by several observers since the early 1950s, the regular or quasi-regular switching between maxima is new. Twenty L/T systems have so far been found in the Kepler database and at least three classes of L/T behavior have been identified. In this presentation I will give an update on the L/T phenomenon gleaned from the Kepler and K2 databases. The Kepler and K2 light curves are being analyzed with the 2015 version of the Wilson-Devinney (WD) program that includes major improvements in modeling star spots (i.e. spot motions due to drift and stellar rotation and spot growth and decay). The prototype L/T variable is WX Draconis (A8V + K0IV, P=1.80 d) which shows L/ T light variations of 2-3%. The primary is a delta Scuti star with a dominant pulsation period of 41 m. Preliminary analysis of the WX Dra data suggests that the L/T variability can be fit with either an accretion hot spot on the primary (T = 2.3 Tphot) that jumps in longitude or a magnetic cool spotted region on the secondary. If the latter model is correct the dark region must occupy at least 20% of the surface of the facing hemisphere of the secondary if it is completely black, or a larger area if not completely black. In both hot and cool spot scenarios magnetic fields must play a role in the activity. Support from NASA grants NNX11AC78G and NNX12AE44G and USC’s Women in Science and Engineering (WiSE) program is greatly appreciated.

Characterization of xylan in the early stages of secondary cell wall formation in tobacco bright yellow-2 cells.

PubMed

Ishii, Tadashi; Matsuoka, Keita; Ono, Hiroshi; Ohnishi-Kameyama, Mayumi; Yaoi, Katsuro; Nakano, Yoshimi; Ohtani, Misato; Demura, Taku; Iwai, Hiroaki; Satoh, Shinobu

2017-11-15

The major polysaccharides present in the primary and secondary walls surrounding plant cells have been well characterized. However, our knowledge of the early stages of secondary wall formation is limited. To address this, cell walls were isolated from differentiating xylem vessel elements of tobacco bright yellow-2 (BY-2) cells induced by VASCULAR-RELATED NAC-DOMAIN7 (VND7). The walls of induced VND7-VP16-GR BY-2 cells consisted of cellulose, pectic polysaccharides, hemicelluloses, and lignin, and contained more xylan and cellulose compared with non-transformed BY-2 and uninduced VND7-VP16-GR BY-2 cells. A reducing end sequence of xylan containing rhamnose and galaturonic acid- residues is present in the walls of induced, uninduced, and non-transformed BY-2 cells. Glucuronic acid residues in xylan from walls of induced cells are O-methylated, while those of xylan in non-transformed BY-2 and uninduced cells are not. Our results show that xylan changes in chemical structure and amounts during the early stages of xylem differentiation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Uranium potential of the Burro Canyon Formation in western Colorado

USGS Publications Warehouse

Craig, L.C.

1982-01-01

The Burro Canyon Formation of Early Cretaceous age overlies the Morrison Formation (Late Jurassic) and underlies the Dakota Sandstone (Late Cretaceous) over most of southeastern Utah and southwestern Colorado. It consists mainly of alternating beds of fluvial sandstone and overbank mudstone with sandstone dominating in the lower part of the formation and mudstone in the upper part. At the outcrop, the sandstones in the formation exhibit almost all the characteristics that are considered favorable for the occurrence of sandstone-type uranium deposits, but only a few small deposits have been discovered in the Colorado-Utah area. The major deficiency of the Burro Canyon in these outcrop areas is the absence of a reductant such as carbonaceous debris, humic or humate materials, or pyrite. Reductants were probably removed during a period of extensive oxidation at the time of deposition and during a subsequent erosional episode prior to deposition of the Dakota Sandstone. The formation reaches a lobate, inexactly located eastern margin that extends from near Meeker, Colorado, southward through the Piceance basin to near Aztec, New Mexico, in the northwestern part of the San Juan Basin. Along much of this distance, the formation is in the subsurface and has been penetrated by only a few drill holes. Along this eastern margin, the lobes project eastward where fluvial distributary streams built minor alluvial fans of relatively high-energy deposits out from the main axis of Burro Canyon stream deposition. The lower and distal reaches of these lobes may have survived the period of post depositional erosion and oxidation in a reduced condition because of low relief and the protection of a high water table. If so, the peripheral and distal parts of these lobes may have retained the precipitants necessary to form a uranium deposit. Two of the lobes extend into the southwest margin of the Piceance Basin and are considered the possible location of uranium deposits. Two additional

In Situ Soft X-ray Spectromicroscopy of Early Tricalcium Silicate Hydration

DOE PAGES

Bae, Sungchul; Kanematsu, Manabu; Hernandez-Cruz, Daniel; ...

2016-12-01

The understanding and control of early hydration of tricalcium silicate (C 3S) is of great importance to cement science and concrete technology. However, traditional characterization methods are incapable of providing morphological and spectroscopic information about in situ hydration at the nanoscale. Using soft X-ray spectromicroscopy, we report the changes in morphology and molecular structure of C 3S at an early stage of hydration. In situ C 3S hydration in a wet cell, beginning with induction (~1 h) and acceleration (~4 h) periods of up to ~8 h, was studied and compared with ex situ measurements in the deceleration period aftermore » 15 h of curing. Analysis of the near-edge X-ray absorption fine structure showed that the Ca binding energy and energy splitting of C 3S changed rapidly in the early age of hydration and exhibited values similar to calcium silicate hydrate (C–S–H). The formation of C–S–H nanoseeds in the C 3S solution and the development of a fibrillar C–S–H morphology on the C 3S surface were visualized. Following this, silicate polymerization accompanied by C–S–H precipitation produced chemical shifts in the peaks of the main Si K edge and in multiple scattering. However, the silicate polymerization process did not significantly affect the Ca binding energy of C–S–H.« less

In Situ Soft X-ray Spectromicroscopy of Early Tricalcium Silicate Hydration

PubMed Central

Bae, Sungchul; Kanematsu, Manabu; Hernández-Cruz, Daniel; Moon, Juhyuk; Kilcoyne, David; Monteiro, Paulo J. M.

2016-01-01

The understanding and control of early hydration of tricalcium silicate (C3S) is of great importance to cement science and concrete technology. However, traditional characterization methods are incapable of providing morphological and spectroscopic information about in situ hydration at the nanoscale. Using soft X-ray spectromicroscopy, we report the changes in morphology and molecular structure of C3S at an early stage of hydration. In situ C3S hydration in a wet cell, beginning with induction (~1 h) and acceleration (~4 h) periods of up to ~8 h, was studied and compared with ex situ measurements in the deceleration period after 15 h of curing. Analysis of the near-edge X-ray absorption fine structure showed that the Ca binding energy and energy splitting of C3S changed rapidly in the early age of hydration and exhibited values similar to calcium silicate hydrate (C–S–H). The formation of C–S–H nanoseeds in the C3S solution and the development of a fibrillar C–S–H morphology on the C3S surface were visualized. Following this, silicate polymerization accompanied by C–S–H precipitation produced chemical shifts in the peaks of the main Si K edge and in multiple scattering. However, the silicate polymerization process did not significantly affect the Ca binding energy of C–S–H. PMID:28774096

Long-term failure of alveologenesis after an early short-term exposure to a PDGF-receptor antagonist.

PubMed

Lau, Mandy; Masood, Azhar; Yi, Man; Belcastro, Rosetta; Li, Jun; Tanswell, A Keith

2011-04-01

Survivors of moderate-to-severe bronchopulmonary dysplasia have impaired alveologenesis lasting at least into early adult life. The mechanisms underlying this long-term effect are unknown. We hypothesized that short-term inhibition of growth factor-mediated early alveolar formation would result in a long-term impairment of subsequent alveologenesis. Neonatal rats were injected daily with the platelet-derived growth factor (PDGF) receptor antagonist, imatinib mesylate, from day 1-7 of life, to inhibit the early alveolar formation occurring by in-growth of secondary crests into precursor saccules. The pups were then allowed to recover for 7, 14, 21, or 58 days. In imatinib-treated pups, DNA synthesis in total lung cells, and specifically in cells of secondary crests, was reduced at day 8 of life, had rebounded on day 14 of life but was then again reduced by day 28 of life. At day 8 of life, imatinib-treated pups had impaired alveologenesis as reflected by a decrease in secondary crests, an increase in alveolar size, and an overall decrease in both estimated alveolar number and generations compared with age-matched controls. No meaningful recovery was observed, even after a 21- or 58-day recovery period. The lungs of imatinib-treated pups had increased fibulin-5 content and an abnormal deposition of elastin. We conclude that reduced signaling through the PDGF pathways, at an early stage of alveologenesis, can result in long-lasting changes in lung architecture. A likely mechanism is through impaired formation of the elastin scaffold required for alveolarization.

Transcriptomic analysis of wound xylem formation in Pinus canariensis.

PubMed

Chano, V; Collada, C; Soto, A

2017-12-04

Woody plants, especially trees, usually must face several injuries caused by different agents during their lives. Healing of injuries in stem and branches, affecting the vascular cambium and xylem can take several years. In conifers, healing takes place mainly from the remaining vascular cambium in the margin of the wound. The woundwood formed in conifers during healing usually presents malformed and disordered tracheids as well as abundant traumatic resin ducts. These characteristics affect its functionality as water conductor and its technological properties. In this work we analyze for the first time the transcriptomic basis of the formation of traumatic wood in conifers, and reveal some differences with normal early- and late-wood. Microarray analysis of the differentiating traumatic wood, confirmed by quantitative RT-PCR, has revealed alterations in the transcription profile of up to 1408 genes during the first period of healing. We have grouped these genes in twelve clusters, according to their transcription profiles, and have distinguished accordingly two main phases during this first healing. Wounding induces a complete rearrangement of the transcriptional program in the cambial zone close to the injuries. At the first instance, radial growth is stopped, and a complete set of defensive genes, mostly related to biotic stress, are induced. Later on, cambial activity is restored in the lateral borders of the wound, even at a high rate. During this second stage certain genes related to early-wood formation, including genes involved in cell wall formation and transcription factors, are significantly overexpressed, while certain late-wood related genes are repressed. Additionally, significant alterations in the transcription profile of abundant non annotated genes are reported.

The Correlation Between Breastfeeding Success in the Early Postpartum Period and the Perception of Self-Efficacy in Breastfeeding and Breast Problems in the Late Postpartum.

PubMed

Kılcı, Hanife; Çoban, Ayden

2016-05-01

The research was conducted to determine the correlation between breastfeeding success in the early postpartum period and the perception of self-efficacy in breastfeeding and breast problems in late postpartum. This analytic and cross-sectional research was carried out at Aydın Obstetrics and Gynecology and Children's Diseases Hospital. Three hundred twenty-seven primipara mothers who had delivered a single baby of healthy term at 37 or more gestational weeks with no previous experience with breastfeeding and who agreed to cooperate participated in the research. The mothers' mean gestational week of delivery was 39.25 ± 1.10 weeks, and it was found that 56.0% had delivered by cesarean section and 57.0% had started to breastfeed immediately after the birth. The mothers' LATCH mean score was 6.55 ± 0.86; their postnatal breastfeeding self-efficacy mean score was found to be 59.10 ± 7.21. Mothers who had high success in breastfeeding at early postpartum were found to experience fewer problems with their breasts (Z = -2.65, p < 0.05), gave birth by vaginal delivery (Z = -2.88, p < 0.05), and had not received anesthesia during the delivery (Z = -2.52, p < 0.05). In the correlation analysis, it was seen that mothers with high success in breastfeeding also had high self-efficacy scores (r = 0.210, p = 0.003). The results of the research indicated that breastfeeding success in the early postpartum period reduced breast problems and increased the perception of breastfeeding self-efficacy in the late postpartum period.

Sea Surface Temperatures in the Indo-Pacific Warm Pool During the Early Pliocene Warm Period

NASA Astrophysics Data System (ADS)

Dekens, P. S.; Ravelo, A. C.; Griffith, E. M.

2010-12-01

The Indo-Pacific warm pool (IPWP) plays an important role in both regional and global climate, but the response of this region to anthropogenic climate change is not well understood. While the early Pliocene is not a perfect analogue for anthropogenic climate change, it is the most recent time in Earth history when global temperatures were warmer than they are today for a sustained period of time. SST in the eastern equatorial Pacific was 2-4○C warmer in the early Pliocene compared to today. A Mg/Ca SST at ODP site 806 in the western equatorial Pacific indicates that SST were stable through the last 5Ma (Wara et al., 2005). We generated a G. sacculifer Mg/Ca record in the Indian Ocean (ODP sit 758) for the last 5 Ma, which also shows that IPWP SST has remained relatively stable through the last 5 Ma and was not warmer in the early Pliocene compared today. A recent paper suggests that the Mg/Ca of seawater may have varied through the last 5 Ma and significantly affected Mg/Ca SST estimates (Medina-Elizalde et al., 2008). However, there is considerable uncertainty in the estimates of seawater Mg/Ca variations through time. We will present a detailed examination of these uncertainties to examine the possible range of seawater Mg/Ca through the last 5 Ma. Due to the lack of culturing work of foraminifera at different Mg/Ca ratios in the growth water there is also uncertainty in how changes in seawater Mg/Ca will affect the temperatures signal in the proxy. We will explore how uncertainties in the record of seawater Mg/Ca variations through time and its effect on the Mg/Ca SST proxy potentially influence the interpretation of the Mg/Ca SST records at ODP sites 806 and 758 in the IPWP, and ODP site 847 in the eastern equatorial Pacific. We will also explore how adjustment of the Mg/Ca SST estimates (due to reconstructed Mg/Ca seawater variations) affects the δ18O of water when adjusted Mg/Ca SST estimates are paired with δ18O measurements of the same samples.

A Novel Chitosan-γPGA Polyelectrolyte Complex Hydrogel Promotes Early New Bone Formation in the Alveolar Socket Following Tooth Extraction

PubMed Central

Chang, Hao-Hueng; Wang, Yin-Lin; Chiang, Yu-Chih; Chen, Yen-Liang; Chuang, Yu-Horng; Tsai, Shang-Jye; Heish, Kuo-Huang; Lin, Feng-Huei; Lin, Chun-Pin

2014-01-01

A novel chitosan-γPGA polyelectrolyte complex hydrogel (C-PGA) has been developed and proven to be an effective dressing for wound healing. The purpose of this study was to evaluate if C-PGA could promote new bone formation in the alveolar socket following tooth extraction. An animal model was proposed using radiography and histomorphology simultaneously to analyze the symmetrical sections of Wistar rats. The upper incisors of Wistar rats were extracted and the extraction sockets were randomly treated with gelatin sponge, neat chitosan, C-PGA, or received no treatment. The extraction sockets of selected rats from each group were evaluated at 1, 2, 4, or 6 wk post-extraction. The results of radiography and histopathology indicated that the extraction sockets treated with C-PGA exhibited lamellar bone formation (6.5%) as early as 2 wk after the extraction was performed. Moreover, the degree of new bone formation was significantly higher (P < 0.05) in the extraction sockets treated with C-PGA at 6 wk post-extraction than that in the other study groups. In this study, we demonstrated that the proposed animal model involving symmetrical sections and simultaneous radiography and histomorphology evaluation is feasible. We also conclude that the novel C-PGA has great potential for new bone formation in the alveolar socket following tooth extraction. PMID:24658174

Fungal infections in children in the early postoperative period after cardiac surgery for congenital heart disease: a single-centre experience.

PubMed

Jaworski, Radoslaw; Haponiuk, Ireneusz; Irga-Jaworska, Ninela; Chojnicki, Maciej; Steffens, Mariusz; Paczkowski, Konrad; Zielinski, Jacek

2016-09-01

Postoperative infections are still an important problem in cardiac surgery, especially in the paediatric population, and may influence the final outcome of congenital heart disease treatment. Postoperative infections with fungi are uncommon. The aetiology is poorly understood, and the proper diagnosis and treatment is unclear. In this single-centre study, the frequency of invasive fungal disease in children who underwent surgical management of congenital heart diseases was determined along with the risk factors for infection, treatment options and outcomes. All consecutive paediatric patients (<18 years of age) who underwent cardiac surgery for congenital heart disease between September 2008 and December 2015 in a paediatric cardiac centre in Poland were identified. Those who developed invasive fungal disease in the early postoperative period (30 days) were identified. Of the 1540 cardiosurgical procedures for congenital heart disease, 6 were complicated by fungal infection (0.39%). One patient had a high probability of fungal infection, but the diagnosis was unproved. Nevertheless, the patient was successfully treated with antifungal treatment. Five had proven invasive fungal disease. Of these, 3 were diagnosed with candidaemia. All had undergone cardiopulmonary bypass. Of the remaining 2 patients, 1 was a preterm newborn with complete atrioventricular septal defect who developed rib fungal invasion. The remaining patient had pulmonary atresia with ventricular septal defect and developed Fournier's gangrene after surgery. None of the patients died due to infection in the early postoperative period. However, the child with rib fungal invasion died 39 days after surgery as a result of multiorgan failure. Fungal infections in paediatric patients after cardiac surgery may markedly influence morbidity and mortality. Fungal infection prophylaxis in this specific group of children may reduce morbidity, whereas early empirical treatment followed by a targeted approach may

Limitation of the Predominant-Period Estimator for Earthquake Early Warning and the Initial Rupture of Earthquakes

NASA Astrophysics Data System (ADS)

Yamada, T.; Ide, S.

2007-12-01

Earthquake early warning is an important and challenging issue for the reduction of the seismic damage, especially for the mitigation of human suffering. One of the most important problems in earthquake early warning systems is how immediately we can estimate the final size of an earthquake after we observe the ground motion. It is relevant to the problem whether the initial rupture of an earthquake has some information associated with its final size. Nakamura (1988) developed the Urgent Earthquake Detection and Alarm System (UrEDAS). It calculates the predominant period of the P wave (τp) and estimates the magnitude of an earthquake immediately after the P wave arrival from the value of τpmax, or the maximum value of τp. The similar approach has been adapted by other earthquake alarm systems (e.g., Allen and Kanamori (2003)). To investigate the characteristic of the parameter τp and the effect of the length of the time window (TW) in the τpmax calculation, we analyze the high-frequency recordings of earthquakes at very close distances in the Mponeng mine in South Africa. We find that values of τpmax have upper and lower limits. For larger earthquakes whose source durations are longer than TW, the values of τpmax have an upper limit which depends on TW. On the other hand, the values for smaller earthquakes have a lower limit which is proportional to the sampling interval. For intermediate earthquakes, the values of τpmax are close to their typical source durations. These two limits and the slope for intermediate earthquakes yield an artificial final size dependence of τpmax in a wide size range. The parameter τpmax is useful for detecting large earthquakes and broadcasting earthquake early warnings. However, its dependence on the final size of earthquakes does not suggest that the earthquake rupture is deterministic. This is because τpmax does not always have a direct relation to the physical quantities of an earthquake.

Early Archean stromatolites: Paleoenvironmental setting and controls on formation

NASA Technical Reports Server (NTRS)

Lowe, D. R.

1991-01-01

The earliest record of terrestrial life is contained in thin, silicified sedimentary layers within enormously thick, predominantly volcanic sequences in South Africa and Western Australia. This record includes bacteria-like microfossils, laminated carbonaceous structures resembling flat bacterial mats and stromatolites, and a morphologically diverse assemblage of carbonaceous particles. These structures and particles and their host sediments provide the only direct source of information on the morphology, paleoecology, and biogeochemistry of early life; the nature of interactions between organisms and surface systems on the early earth; and possible settings within which life might have evolved. The three known occurrences of 3.5 to 3.2 billion-year-old stromalites were evaluated in terms of depositional setting and biogenicity.

Unraveling Mixed Hydrate Formation: Microscopic Insights into Early Stage Behavior.

PubMed

Hall, Kyle Wm; Zhang, Zhengcai; Kusalik, Peter G

2016-12-29

The molecular-level details of mixed hydrate nucleation remain unclear despite the broad implications of this process for a variety of scientific domains. Through analysis of mixed hydrate nucleation in a prototypical CH 4 /H 2 S/H 2 O system, we demonstrate that high-level kinetic similarities between mixed hydrate systems and corresponding pure hydrate systems are not a reliable basis for estimating the composition of early stage mixed hydrate nuclei. Moreover, we show that solution compositions prior to and during nucleation are not necessarily effective proxies for the composition of early stage mixed hydrate nuclei. Rather, microscopic details, (e.g., guest-host interactions and previously neglected cage types) apparently play key roles in determining early stage behavior of mixed hydrates. This work thus provides key foundational concepts and insights for understanding mixed hydrate nucleation.

Sulfur in the Early Martian Atmosphere Revisited: Experiments with a 3-D Global Climate Model

NASA Astrophysics Data System (ADS)

Kerber, L.; Forget, F.; Wordsworth, R.

2013-09-01

Data returned from the surface of Mars during the 1970s revealed intriguing geological evidence for a warmer and wetter early martian climate. Dendritic valley networks were discovered by Mariner 9 on ancient Noachian terrain [1], indicating that liquid water had flowed across the surface in the distant past. Since this time, geological investigations into early Martian history have attempted to ascertain the nature and level of activity of the early Martian hydrological cycle [e.g. 2-5] while atmospheric modeling efforts have focused on how the atmosphere could be warmed to temperatures great enough to sustain such activity [see 6-7 for reviews]. Geological and spectroscopic investigations have refined the history and chronology of Noachian Mars over time, and circulation of liquid water has been invoked to explain several spatially and temporally distinct morphological and chemical signatures found in the geological record. Detections of iron and magnesium-rich clays are widespread in the oldest Martian terrains, suggesting a period of pH-neutral aqueous alteration [e.g., 8]. Valley network incision also took place during the Noachian period [9]. Some chains of river valleys and craters lakes extend for thousands of kilometers, suggesting temperatures at least clement enough for sustained ice-covered flow [3,10]. The commencement of valley network incision is not well constrained, but the period of Mg/Fe clay formation appears to have ended before the termination of valley network formation, as the visible fluvial systems appear to have remobilized existing clays rather than forming them [5,8]. There is also evidence that the cessation of valley network formation was abrupt [11]. Towards the end of the Noachian, erosion rates appear to have been significantly higher than during subsequent periods, a process that has also been attributed to aqueous processes [12]. A period of sulfate formation followed, likely characterized by acidic, evaporitic playa environments

Inviscid Analysis of Extended Formation Flight

NASA Technical Reports Server (NTRS)

Kless, James; Aftosmis, Michael J.; Ning, Simeon Andrew; Nemec, Marian

2012-01-01

Flying airplanes in extended formations, with separation distances of tens of wingspans, significantly improves safety while maintaining most of the fuel savings achieved in close formations. The present study investigates the impact of roll trim and compressibility at fixed lift coefficient on the benefits of extended formation flight. An Euler solver with adjoint-based mesh refinement combined with a wake propagation model is used to analyze a two-body echelon formation at a separation distance of 30 spans. Two geometries are examined: a simple wing and a wing-body geometry. Energy savings, quantified by both formation drag fraction and span efficiency factor, are investigated at subsonic and transonic speeds for a matrix of vortex locations. The results show that at fixed lift and trimmed for roll, the optimal location of vortex impingement is about 10% inboard of the trailing airplane s wing-tip. Interestingly, early results show the variation in drag fraction reduction is small in the neighborhood of the optimal position. Over 90% of energy benefits can be obtained with a 5% variation in transverse and 10% variation in crossflow directions. Early results suggest control surface deflections required to achieve trim reduce the benefits of formation flight by 3-5% at subsonic speeds. The final paper will include transonic effects and trim on extended formation flight drag benefits.

Observational Evidence Against Mountain-Wave Generation of Ice Nuclei as a Prerequisite for the Formation of Three Solid Nitric Acid Polar Stratospheric Clouds Observed in the Arctic in Early December 1999

NASA Technical Reports Server (NTRS)

Pagan, Kathy L.; Tabazadeh, Azadeh; Drdla, Katja; Hervig, Mark E.; Eckermann, Stephen D.; Browell, Edward V.; Legg, Marion J.; Foschi, Patricia G.

2004-01-01

A number of recently published papers suggest that mountain-wave activity in the stratosphere, producing ice particles when temperatures drop below the ice frost point, may be the primary source of large NAT particles. In this paper we use measurements from the Advanced Very High Resolution Radiometer (AVHRR) instruments on board the National Oceanic and Atmospheric Administration (NOAA) polar-orbiting satellites to map out regions of ice clouds produced by stratospheric mountain-wave activity inside the Arctic vortex. Lidar observations from three DC-8 flights in early December 1999 show the presence of solid nitric acid (Type Ia or NAT) polar stratospheric clouds (PSCs). By using back trajectories and superimposing the position maps on the AVHRR cloud imagery products, we show that these observed NAT clouds could not have originated at locations of high-amplitude mountain-wave activity. We also show that mountain-wave PSC climatology data and Mountain Wave Forecast Model 2.0 (MWFM-2) raw hemispheric ray and grid box averaged hemispheric wave temperature amplitude hindcast data from the same time period are in agreement with the AVHRR data. Our results show that ice cloud formation in mountain waves cannot explain how at least three large scale NAT clouds were formed in the stratosphere in early December 1999.

Probing the early stages of shock-induced chondritic meteorite formation at the mesoscale

PubMed Central

Rutherford, Michael E.; Chapman, David J.; Derrick, James G.; Patten, Jack R. W.; Bland, Philip A.; Rack, Alexander; Collins, Gareth S.; Eakins, Daniel E.

2017-01-01

Chondritic meteorites are fragments of asteroids, the building blocks of planets, that retain a record of primordial processes. Important in their early evolution was impact-driven lithification, where a porous mixture of millimetre-scale chondrule inclusions and sub-micrometre dust was compacted into rock. In this Article, the shock compression of analogue precursor chondrite material was probed using state of the art dynamic X-ray radiography. Spatially-resolved shock and particle velocities, and shock front thicknesses were extracted directly from the radiographs, representing a greatly enhanced scope of data than could be measured in surface-based studies. A statistical interpretation of the measured velocities showed that mean values were in good agreement with those predicted using continuum-level modelling and mixture theory. However, the distribution and evolution of wave velocities and wavefront thicknesses were observed to be intimately linked to the mesoscopic structure of the sample. This Article provides the first detailed experimental insight into the distribution of extreme states within a shocked powder mixture, and represents the first mesoscopic validation of leading theories concerning the variation in extreme pressure-temperature states during the formation of primordial planetary bodies. PMID:28555619

Tracing sexual identities in "old age": gender and seniority in advice literature of the early-modern and modern periods.

PubMed

van Tilburg, Marja

2009-10-01

Thus far, historians have interpreted representations of elderly women with reference to women's roles or to women's positions in society. This article proposes a different approach toward gender: to relate representations of the aged to the sexual identities of both men and women. This article analyzes representations of old age in conduct books of the early-modern period and the nineteenth century. By drawing a comparison, the eighteenth-century change of "identity regime" in European culture is brought to the fore. The article points to the influence of sexual identities on the representations of senior persons in advice literature both in Dutch and translated into Dutch.

Pyrite-Induced Hydrogen Peroxide Formation as a Driving Force in the Evolution of Photosynthetic Organisms on an Early Earth

NASA Astrophysics Data System (ADS)

Borda, Michael J.; Elsetinow, Alicia R.; Schoonen, Martin A.; Strongin, Daniel R.

2001-09-01

The remarkable discovery of pyrite-induced hydrogen peroxide (H2O2) provides a key step in the evolution of oxygenic photosynthesis. Here we show that H2O2 can be generated rapidly via a reaction between pyrite and H2O in the absence of dissolved oxygen. The reaction proceeds in the dark, and H2O2 levels increase upon illumination with visible light. Since pyrite was stable in most photic environments prior to the rise of O2 levels, this finding represents an important mechanism for the formation of H2O2 on early Earth.

[Analgesic effect of TES therapy in the early postoperative period in patients who underwent tonsillectomy].

PubMed

Semënov, F V; Kade, A Kh; Banashek-Meshchiarkova, T V; Vartanian, M S

2013-01-01

The objective of the present work was to study peculiarities of the analgesic action of therapeutic electrical stimulation (TES therapy) in the early postoperative period in the patients who underwent tonsillectomy. A total of 60 patients admitted for this surgery to the specialized otorhinolaryngological department were available for observation. They were divided into two groups depending on the pain relief strategy. The patients of the study group (n=30) underwent courses of transcranial electrical stimulation on a daily basis (from the onset of hospitalization) in addition to the administration of a standard analgetic. The standard dose of tramadol (2.0 ml) was given to the patients of the control group (n=30) who complained of strong pain. The results of the objective and subjective estimations indicate that the degree of pharyngeal pain in the patients treated with TES therapy and the standard analgetic was significantly different. The patients receiving TES therapy could sooner resume their habitual diet and required smaller amounts of the analgetic which makes this modality a cost-effective supplement to the standard postoperative treatment.

An ALMA view of star formation efficiency suppression in early-type galaxies after gas-rich minor mergers

NASA Astrophysics Data System (ADS)

van de Voort, Freeke; Davis, Timothy A.; Matsushita, Satoki; Rowlands, Kate; Shabala, Stanislav S.; Allison, James R.; Ting, Yuan-Sen; Sansom, Anne E.; van der Werf, Paul P.

2018-05-01

Gas-rich minor mergers contribute significantly to the gas reservoir of early-type galaxies (ETGs) at low redshift, yet the star formation efficiency (SFE; the star formation rate divided by the molecular gas mass) appears to be strongly suppressed following some of these events, in contrast to the more well-known merger-driven starbursts. We present observations with the Atacama Large Millimeter/submillimeter Array (ALMA) of six ETGs, which have each recently undergone a gas-rich minor merger, as evidenced by their disturbed stellar morphologies. These galaxies were selected because they exhibit extremely low SFEs. We use the resolving power of ALMA to study the morphology and kinematics of the molecular gas. The majority of our galaxies exhibit spatial and kinematical irregularities, such as detached gas clouds, warps, and other asymmetries. These asymmetries support the interpretation that the suppression of the SFE is caused by dynamical effects stabilizing the gas against gravitational collapse. Through kinematic modelling we derive high velocity dispersions and Toomre Q stability parameters for the gas, but caution that such measurements in edge-on galaxies suffer from degeneracies. We estimate merger ages to be about 100 Myr based on the observed disturbances in the gas distribution. Furthermore, we determine that these galaxies lie, on average, two orders of magnitude below the Kennicutt-Schmidt relation for star-forming galaxies as well as below the relation for relaxed ETGs. We discuss potential dynamical processes responsible for this strong suppression of star formation surface density at fixed molecular gas surface density.

Africa was still far south in the Late Ypresian: Paleomagnetic study on the early Eocene 'Minia' formation in central Egypt

NASA Astrophysics Data System (ADS)

Lotfy, H.; Heleika, M. Abu; Mostafa, R.; Wahbah, D.

2017-12-01

The paleomagnetic study was carried out on three sections of the Late Ypresian "Minia" formation limestone, in order to shed light on the paleolatitude of northeast Africa upon the end of the Early Eocene. The initial study on the anisotropy of magnetic susceptibility [AMS] helped in confining the paleomagnetic sampling to the virtually isotropic limestone beds. The subsequent stepwise thermal demagnetization of the three-axis isothermal remanence acquired in one sample of each sampled site, revealed the limited contribution of goethite and hematite with the main remanence carrier magnetite in most samples.

Effects of brief daily periods of unrestricted vision during early monocular form deprivation on development of visual area 2.

PubMed

Zhang, Bin; Tao, Xiaofeng; Wensveen, Janice M; Harwerth, Ronald S; Smith, Earl L; Chino, Yuzo M

2011-09-14

Providing brief daily periods of unrestricted vision during early monocular form deprivation reduces the depth of amblyopia. To gain insights into the neural basis of the beneficial effects of this treatment, the binocular and monocular response properties of neurons were quantitatively analyzed in visual area 2 (V2) of form-deprived macaque monkeys. Beginning at 3 weeks of age, infant monkeys were deprived of clear vision in one eye for 12 hours every day until 21 weeks of age. They received daily periods of unrestricted vision for 0, 1, 2, or 4 hours during the form-deprivation period. After behavioral testing to measure the depth of the resulting amblyopia, microelectrode-recording experiments were conducted in V2. The ocular dominance imbalance away from the affected eye was reduced in the experimental monkeys and was generally proportional to the reduction in the depth of amblyopia in individual monkeys. There were no interocular differences in the spatial properties of V2 neurons in any subject group. However, the binocular disparity sensitivity of V2 neurons was significantly higher and binocular suppression was lower in monkeys that had unrestricted vision. The decrease in ocular dominance imbalance in V2 was the neuronal change most closely associated with the observed reduction in the depth of amblyopia. The results suggest that the degree to which extrastriate neurons can maintain functional connections with the deprived eye (i.e., reducing undersampling for the affected eye) is the most significant factor associated with the beneficial effects of brief periods of unrestricted vision.

Effects of Brief Daily Periods of Unrestricted Vision during Early Monocular Form Deprivation on Development of Visual Area 2

PubMed Central

Zhang, Bin; Tao, Xiaofeng; Wensveen, Janice M.; Harwerth, Ronald S.; Smith, Earl L.

2011-01-01

Purpose. Providing brief daily periods of unrestricted vision during early monocular form deprivation reduces the depth of amblyopia. To gain insights into the neural basis of the beneficial effects of this treatment, the binocular and monocular response properties of neurons were quantitatively analyzed in visual area 2 (V2) of form-deprived macaque monkeys. Methods. Beginning at 3 weeks of age, infant monkeys were deprived of clear vision in one eye for 12 hours every day until 21 weeks of age. They received daily periods of unrestricted vision for 0, 1, 2, or 4 hours during the form-deprivation period. After behavioral testing to measure the depth of the resulting amblyopia, microelectrode-recording experiments were conducted in V2. Results. The ocular dominance imbalance away from the affected eye was reduced in the experimental monkeys and was generally proportional to the reduction in the depth of amblyopia in individual monkeys. There were no interocular differences in the spatial properties of V2 neurons in any subject group. However, the binocular disparity sensitivity of V2 neurons was significantly higher and binocular suppression was lower in monkeys that had unrestricted vision. Conclusions. The decrease in ocular dominance imbalance in V2 was the neuronal change most closely associated with the observed reduction in the depth of amblyopia. The results suggest that the degree to which extrastriate neurons can maintain functional connections with the deprived eye (i.e., reducing undersampling for the affected eye) is the most significant factor associated with the beneficial effects of brief periods of unrestricted vision. PMID:21849427

Thyroid Hormones Concentrations during the Mid-Dry Period: An Early Indicator of Fatty Liver in Holstein-Friesian Dairy Cows

PubMed Central

Šamanc, Horea; Stojić, Velibor; Kirovski, Danijela; Jovanović, Milijan; Cernescu, Horia; Vujanac, Ivan

2010-01-01

Relationship between postpartal fatty liver and thyroid gland activity during the peripartal and mid dry periods was studied. Twenty one dry cows were chosen. Blood samples were obtained on days −30, −2, and +12 related to calving and analized for thyroxine (T4) and triiodothyronine (T3). A T3/T4 ratio was calculated. Liver tissue samples were taken 12 d after calving and tested for the lipid content. Cows were divided into three groups: mild (<20% fat), moderate (20 to 30%), or severe fatty liver (>30%). Cows, that were affected with severe fatty liver, were hypothyroid prior to development of the condition due to lower T4 concentrations, and had significantly lower concentration of T3 and higher T3/T4 ratios than cows with mild and moderate fatty liver. Thus, hypothyroid state during mid-dry period may be an early indicator of postpartal fatty liver and may provoke T3/T4 ratio increase in this group of cows. PMID:21048844

Evidence for live 247Cm in the early solar system

USGS Publications Warehouse

Tatsumoto, M.; Shimamura, T.

1980-01-01

Variations of the 238U/235U ratio in the Allende meteorite, ranging from -35% to + 19%, are interpreted as evidence of live 247Cm in the early Solar System. The amounts of these and other r-products in the Solar System indicate values of (9,000??3,000) Myr for the age of the Galaxy and ??? 8 Myr for the time between the end of nucleosynthesis and the formation of meteoritic grains. Three possible explanations are presented for the different values of the latter time period which are indicated by the decay products of 247Cm, 26Al, 244Pu and 129I. ?? 1980 Nature Publishing Group.

Geologic Reconnaissance of the Antelope-Ashwood Area, North-Central Oregon: With Emphasis on the John Day Formation of Late Oligocene and Early Miocene Age

USGS Publications Warehouse

Peck, Dallas L.

1964-01-01

This report briefly describes the geology of an area of about 750 square miles in Jefferson, Wasco, Crook, and Wheeler Counties, Oregon. About 16,000 feet of strata that range in age from pre-Tertiary to Quaternary are exposed. These include the following units: pre-Tertiary slate, graywacke, conglomerate, and meta-andesite; Clarno Formation of Eocene age - lava flows, volcanic breccia, tuff, and tuffaceous mudstone, chiefly of andesitic composition; John Day Formation of late Oligocene and early Miocene age - pyroclastic rocks, flows, and domes, chiefly of rhyolitic composition; Columbia River Basalt of middle Miocene age - thick, columnar jointed flows of very fine grained dense dark-gray basalt; Dalles Formation of Pliocene age - bedded tuffaceous sandstone, siltstone, and conglomerate; basalt of Pliocene or Pleistocene age - lava flows of porous-textured olivine basalt; and Quaternary loess, landslide debris, and alluvium. Unconformities separate pre-Tertiary rocks and Clarno Formation, Clarno and John Day Formations, John Day Formation and Columbia River Basalt, and Columbia River Basalt and Dalles Formation. The John Day Formation, the only unit studied in detail, consists of about 4,000 feet of tuff, lapilli tuff, strongly to weakly welded rhyolite ash flows, and less abundant trachyandesite flows and rhyolite flows and domes. The formation was divided into nine mappable members in part of the area, primarily on the basis of distinctive ledge-forming welded ash-flow sheets. Most of the sheets are composed of stony rhyolite containing abundant lithophysae and sparse phenocrysts. One sheet contains 10 to 20 percent phenocrysts, mostly cryptoperthitic soda sanidine, but including less abundant quartz, myrmekitic intergrowths of quartz and sanidine, and oligoclase. The rhyolitic ash flows and lava flows were extruded from nearby vents, in contrast to some of the interbedded air-fall tuff and lapilli tuff of dacitic and andesitic composition that may have been

Impact-induced shock and the formation of natural quasicrystals in the early solar system

NASA Astrophysics Data System (ADS)

Hollister, Lincoln S.; Bindi, Luca; Yao, Nan; Poirier, Gerald R.; Andronicos, Christopher L.; MacPherson, Glenn J.; Lin, Chaney; Distler, Vadim V.; Eddy, Michael P.; Kostin, Alexander; Kryachko, Valery; Steinhardt, William M.; Yudovskaya, Marina; Eiler, John M.; Guan, Yunbin; Clarke, Jamil J.; Steinhardt, Paul J.

2014-06-01

The discovery of a natural quasicrystal, icosahedrite (Al63Cu24Fe13), accompanied by khatyrkite (CuAl2) and cupalite (CuAl) in the CV3 carbonaceous chondrite Khatyrka has posed a mystery as to what extraterrestrial processes led to the formation and preservation of these metal alloys. Here we present a range of evidence, including the discovery of high-pressure phases never observed before in a CV3 chondrite, indicating that an impact shock generated a heterogeneous distribution of pressures and temperatures in which some portions reached at least 5 GPa and 1,200 °C. The conditions were sufficient to melt Al-Cu-bearing minerals, which then rapidly solidified into icosahedrite and other Al-Cu metal phases. The meteorite also contains heretofore unobserved phases of iron-nickel and iron sulphide with substantial amounts of Al and Cu. The presence of these phases in Khatyrka provides further proof that the Al-Cu alloys are natural products of unusual processes that occurred in the early solar system.

AWBATTM: Early Clinical Experience

PubMed Central

Vandenberg, Victoria B.

2010-01-01

Objective: The purpose of this article is to describe the early clinical experience with AWBAT. Methods: Burn patients requiring (1) donor sites or (2) treatment of a superficial burn wound injury were treated. A total of 45 patients with 69 distinct wounds were included. AWBATTM-D was evaluated in donor sites and AWBATTM-S was evaluated in superficial partial-thickness burns. Days to healing, pain, hematoma/seroma formation, and infection were noted. Ease of application, adherence, transparency, and physical adaptability details were collected. Results: Average period to healing of donor sites treated with AWBAT-D (n=22 patients with n=26 wounds) was 11.2 days, σ =1.95, with a range of 8–15 days and a median of 11 days. Pain rating at 24 hours was 1.2, σ =0.43 (n=18) and at 48 hours mean was 1.2, σ =0.46 (n=15). Average period to healing of superficial burns treated with AWBAT-S (n=15 patients with n=18 wounds) was 8.1 days, σ =2.48, with a range of 5–13 days and a median of 7 days. Pain rating at 24 hours was 1.5, σ =0.85 (n=10) and at 48 hours mean was 1.75, σ =0.89 (n=8). There was zero incidence of hematoma/seroma. No infections were seen. Results indicate that AWBAT was easily applied with good initial adherence. It was noted to be transparent, conformant, and pliable. Discussion: Early experience demonstrates that AWBAT performs well on donor sites and superficial partial-thickness burns and delivers the desired attributes of a temporary skin substitute including good adherence, infection control, transparency, adapatability, and pain control. PMID:20361005

Early structural and functional plasticity alterations in a susceptibility period of DYT1 dystonia mouse striatum

PubMed Central

Maltese, Marta; Stanic, Jennifer; Tassone, Annalisa; Sciamanna, Giuseppe; Ponterio, Giulia; Vanni, Valentina; Martella, Giuseppina; Imbriani, Paola; Bonsi, Paola; Mercuri, Nicola Biagio

2018-01-01

The onset of abnormal movements in DYT1 dystonia is between childhood and adolescence, although it is unclear why clinical manifestations appear during this developmental period. Plasticity at corticostriatal synapses is critically involved in motor memory. In the Tor1a+/Δgag DYT1 dystonia mouse model, long-term potentiation (LTP) appeared prematurely in a critical developmental window in striatal spiny neurons (SPNs), while long-term depression (LTD) was never recorded. Analysis of dendritic spines showed an increase of both spine width and mature mushroom spines in Tor1a+/Δgag neurons, paralleled by an enhanced AMPA receptor (AMPAR) accumulation. BDNF regulates AMPAR expression during development. Accordingly, both proBDNF and BDNF levels were significantly higher in Tor1a+/Δgag mice. Consistently, antagonism of BDNF rescued synaptic plasticity deficits and AMPA currents. Our findings demonstrate that early loss of functional and structural synaptic homeostasis represents a unique endophenotypic trait during striatal maturation, promoting the appearance of clinical manifestations in mutation carriers. PMID:29504938

Dietary factors during early life program bone formation in female rats

USDA-ARS?s Scientific Manuscript database

Nutritional status during intrauterine and early postnatal life impacts the risk of chronic diseases; however, evidence for an association between early life dietary factors and bone health in adults is limited. Soy protein isolate (SPI) may be one such dietary factor that promotes bone accretion du...

Microanalyzes of remarkable microfossils of the Late Mesoproterozoic-Early Neoproterozoic

NASA Astrophysics Data System (ADS)

Cornet, Yohan; Beghin, Jérémie; Baludikay, Blaise; François, Camille; Storme, Jean-Yves; Compère, Philippe; Javaux, Emanuelle

2016-04-01

The Late Mesoproterozoic-Early Neoproterozoic is an important period to investigate the diversification of early eukaryotes [1]. Following the first appearance of red algae in the Late Mesoproterozoic, other (morphological or molecular) fossils of crown groups are recorded during the Early Neoproterozoic, including green algae, sponges, amoebozoa and possibly fungi. Other microfossils also includes unambiguous eukaryotes, including several distinctive forms for that time period, such as the acritarchs Cerebrosphaera buickii (˜820-720 Ma), Trachyhystrichosphaera aimika and T . botula (1100-720 Ma), and the multicellular eukaryotic problematicum taxon Jacutianema solubila (1100-?720 Ma). To further characterize the taxonomy of these microfossils and to test hypotheses about their possible relationships to crown groups, we combine analyzes of their morphology, wall ultrastructure and microchemistry, using optical microscopy, Scanning and Transmission Electron microscopy (SEM and TEM), as well as Raman and FTIR microspectroscopy respectively. Cerebrosphaera populations from the Svanbergfjellet formation, Spitsbergen, and from the Kanpa Formation, Officer Basin, Australia, include organic vesicles with dark and robust walls ornamented by cerebroid folds [2]. Our study shows the occurrence of complex tri- or bi-layered wall ultrastructures and a highly aromatic composition [3]. The genus Trachyhystrichosphaera includes various species characterized by the presence of a variable number of hollow heteromorphic processes [2]. Preliminary infrared microspectroscopy analyzes performed on two species, T. aimika and T. botula, from the 1.1 Ga Taoudeni Basin, Mauritania, and from the ˜1.1 - 0.8 Ga Mbuji-Mayi Supergroup, RDC, indicate a strong aliphatic and carbonyl composition of the wall biopolymer, with some differences linked to thermal maturity between the two locations. TEM is also performed to characterize the wall ultrastructure of these two species. Various morphotypes

High-resolution carbonate isotopic study of the Mural Formation (Cerro Pimas section), Sonora, México: Implications for early Albian oceanic anoxic events

NASA Astrophysics Data System (ADS)

Madhavaraju, J.; Lee, Yong Il; Scott, R. W.; González-León, C. M.; Jenkyns, H. C.; Saucedo-Samaniego, J. C.; Ramasamy, S.

2018-03-01

The 420-m thick stratigraphic section of the Mural Formation that is exposed in the Cerro Pimas area of northern Sonora, Mexico, is composed of limestone lithofacies ranging from bioclastic wackestone to boundstone, whose biota is characterized by low diversity. Prominent age-diagnostic fossils are benthic foraminifera and long-ranging calcareous algae that indicate the Aptian/Albian boundary is close to the base of the Los Coyotes Member. The carbonates of this formation have negative to positive δ13C values (-4.63 to +2.6‰) and highly depleted δ18O values that range from -12.74 to -8.34‰. The absence of correlation between δ13C and δ18O values supports a primary marine origin for the δ13C values of these limestones. The carbon-isotopic curve of the Cerro Pimas stratigraphic section has well-defined δ13C segments (C8 - C15) that compare with published curves of similar age. In the lower part of the early Albian Los Coyotes Member, the presence of OAE 1b is indicated by an increase followed by a decrease in δ13C values, suggesting correlation with the Kilian Event. The middle part of the Los Coyotes Member has a significant negative carbon-isotope excursion correlated with the globally recognizable early Albian Paquier event. Moreover, another significant negative carbon-isotope shift is observed in the upper part of the Los Coyotes Member, which can be correlated with the Leenhardt Event. The occurrence of the Kilian, Paquier and Leenhardt Events (OAE 1b cluster) in the Cerro Pimas stratigraphy confirms the global nature of these early Albian disturbances of the carbon cycle.

Conditions on Early Mars Might Have Fostered Rapid and Early Development of Life

NASA Technical Reports Server (NTRS)

Gibson, Everett K.; McKay, David S.; Thomas-Keprta, Kathie L.; Clemett, Simon J.; Wentworth, Susan J.

2007-01-01

The exploration of Mars during the past decades has begun to unveil the history of the planet. The combinations of remote sensing, in situ geochemical compositional measurements and photographic observations from both above and on the surface have shown Mars to have a dynamic and active geologic evolution. Mars geologic evolution clearly had conditions that were suitable for supporting life. For a planet to be able to be habitable, it must have water, carbon sources, energy sources and a dynamic geologic past. Mars meets all of these requirements. The first 600 My of Martian history were ripe for life to develop because of the abundance of (i) Water-carved canyons and oceans or lakes with the early presence of near surface water shown by precipitated carbonates in ALH84001 well-dated at approx.3.9 Gy., (ii) Energy from the original accretional processes, a molten core which generated a strong magnetic field leaving a permanent record in the early crust, early active volcanism continuing throughout Martian history, and, and continuing impact processes, (iii) Carbon and water from possibly extensive volcanic outgassing (i.e. H2O, CO2, CH4, CO, O2, N2, H2S, SO2, etc.) and (iv) some crustal tectonics as revealed by faulting and possible plate movement reflected by the magnetic pattern in the crust. The question arises: "Why would life not evolve from these favorable conditions on early Mars in its first 600 My?" During this period, it seems likely that environmental near-surface conditions on Mars were more favorable to life than at any later time. Standing bodies of water, precipitation and flowing surface water, and possibly abundant hydrothermal energy would all favor the formation of early life. Even if life developed elsewhere (on Earth, Venus, or on other solar systems) and was transported to Mars, the surface conditions were likely very hospitable for that introduced life to multiply and evolve.

The role of suture cutout in the failure of meniscal root repair during the early post-operative period: a biomechanical study.

PubMed

Perez-Blanca, Ana; Prado Nóvoa, María; Lombardo Torre, Maximiano; Espejo-Reina, Alejandro; Ezquerro Juanco, Francisco; Espejo-Baena, Alejandro

2018-04-01

To assess the role of suture cutout in the mechanics of failure of the repaired posterior meniscal root during the early post-operative period when using sutures of different shape. Twenty medial porcine menisci were randomized in two groups depending on the suture shape used to repair the posterior root: thread or tape. The sutured menisci were subjected to cyclic loading (1000 cycles, (10, 30) N) followed by load-to-failure testing. Residual displacements, stiffness, and ultimate failure load were determined. During tests, the tissue-suture interface was recorded using a high-resolution camera. In cyclic tests, cutout progression at the suture insertion points was not observed for any specimen of either group and no differences in residual displacements were found between use of thread or tape. In load-to-failure tests, suture cutout started in all menisci at a load close to the ultimate failure and all specimens failed by suture pullout. Suture tape had a greater ultimate load with no other differences. In a porcine model of a repaired posterior meniscal root subjected to cyclic loads representative of current rehabilitation protocols in the early post-operative period under restricted loading conditions, suture cutout was not found as a main source of permanent root displacement when using suture thread or tape. Suture cutout progression started at high loading levels close to the ultimate load of the construct. Tape, with a meniscus-suture contact area larger than thread, produced higher ultimate load.