Influence of enhanced melt supply on upper crustal structure at a mid-ocean ridge discontinuity: A three-dimensional seismic tomographic study of 9°N East Pacific Rise

We present a three-dimensional upper crustal model of the 9°03′N overlapping spreading center (OSC) on the East Pacific Rise that assists in understanding the relationship between melt sills and upper crustal structure at a ridge discontinuity with enhanced melt supply at crustal levels. Our P wave velocity model obtained from tomographic inversion of ∼70,000 crustal first arrival travel times suggests that the geometry of extrusive emplacement are significantly different beneath the overlapping spreading limbs. Extrusive volcanic rocks above the western melt sill are inferred to be thin (∼250 m). More extensive accumulation of extrusives is inferred to the west than to the east of the western melt sill. The extrusive layer inferred above the eastern melt sill thickens from ∼350 (at the neovolcanic axis) to 550 m (to the west of the melt sill). Volcanic construction is likely to be significant in the formation of ridge crest morphology at the OSC, particularly at the tip of the eastern limb. On the basis of our interpretation of the velocity model, we propose that enhanced magma supply at crustal levels at the OSC may provide an effective mechanism for the migration of ridge discontinuities. This “dynamic magma supply model” may explain the commonly observed nonsteady migration pattern of ridge discontinuities by attributing this to the temporal fluctuations in melt availability to the overlapping spreading limbs

The Colorado Plateau Coring Project (CPCP): 100 Million Years of Earth System History

Lasting over 100 million years, the early Mesozoic (252 to 145 Ma) is punctuated by two of the five major mass extinctions of the Phanerozoic (Permo-Triassic and Triassic-Jurassic) plus several smaller extinction events. It witnessed the evolutionary appearance of the modem terrestrial biota including frogs, salamanders, turtles, lizards, crocodilians, dinosaurs, birds, and mammals, and spans a time of dramatic climate changes on the continents. What is arguably the richest record of these events lies in the vast (- 2.5 million km2) complex of epicontinental basins in the western part of Pangea, now largely preserved on the Colorado Plateau (Fig.l). Since the mid-19th century, classic studies of these basins, their strata, and their fossils have made this succession instrumental in framing our context of the early Mesozoic Earth system as reflected in the international literature. Despite this long and distinguished history of study of the Colorado Plateau region, striking ambiguities in temporal resolution, major uncertainties in global correlations, and significant doubts about paleolatitudinal position hamper incorporation of the huge amount of information from the region into-tests of major competing climatic, biotic, and tectonic hypotheses and a fundamental understanding of Earth system processes

Diffusion quantum Monte Carlo study of three-dimensional Wigner crystals

We report diffusion quantum Monte Carlo calculations of three-dimensional Wigner crystals in the density range r_s=100-150. We have tested different types of orbital for use in the approximate wave functions but none improve upon the simple Gaussian form. The Gaussian exponents are optimized by directly minimizing the diffusion quantum Monte Carlo energy. We have carefully investigated and sought to minimize the potential biases in our Monte Carlo results. We conclude that the uniform electron gas undergoes a transition from a ferromagnetic fluid to a body-centered-cubic Wigner crystal at r_s=106+/-1. The diffusion quantum Monte Carlo results are compared with those from Hartree-Fock and Hartree theory in order to understand the role played by exchange and correlation in Wigner crystals. We also study "floating" Wigner crystals and give results for their pair-correlation functions

Approaches to teacher's information and communication competetnce development in the context of the educational cloud computing environment

У статті подано підходи до розвитку інформаційно-комунікаційної компетентності вчителя у контексті міжнародних підходів. Розглянуто рамки цифрової компетентності громадян та освітян, які слугують еталонною моделлю для освітніх систем країн Європи. Визначено основні проблеми та окреслено перспективи використання міжнародних рамок та стандартів у розвитку професійних якостей вчителя.В статье представлены подходы к развитию информационно-коммуникационной компетентности учителя в контексте международных подходов. Рассмотрены рамки цифровой компетентности граждан и педагогов, служащих эталонной моделью для образовательных систем стран Европы. Определены основные проблемы и намечены перспективы использования международных рамок и стандартов в развитии профессиональных качеств учителя.The approaches to the information and communication competence development in the context of international tendencies are revealed in the article.The framework of digital competence of citizens and educators, which serve as a reference model for educational systems of European countries, is considered. The main problems are identified and the perspectives of the use of international frameworks and standards in the development of professional qualities of the teacher are outlined

Galaxy Dynamics Predictions in the Nonsymmetric Gravitational Theory

In the weak field approximation, the nonsymmetric gravitational theory has, in addition to the Newtonian gravitational potential, a Yukawa potential produced by the exchange of a spin $1^+$ boson between fermions. If the range $r_0$ is of order $30$ kpc, then the potential due to the interaction of known neutrinos in the halos of galaxies can explain the flat rotation curves of galaxies. The results are based on a physical linear approximation to the NGT field equations and they are consistent with equivalence principle observations, other solar system gravitational experiments and the binary pulsar data.Comment: 10 pages, plain TeX macro include

HI in the Outskirts of Nearby Galaxies

The HI in disk galaxies frequently extends beyond the optical image, and can trace the dark matter there. I briefly highlight the history of high spatial resolution HI imaging, the contribution it made to the dark matter problem, and the current tension between several dynamical methods to break the disk-halo degeneracy. I then turn to the flaring problem, which could in principle probe the shape of the dark halo. Instead, however, a lot of attention is now devoted to understanding the role of gas accretion via galactic fountains. The current $\rm \Lambda$ cold dark matter theory has problems on galactic scales, such as the core-cusp problem, which can be addressed with HI observations of dwarf galaxies. For a similar range in rotation velocities, galaxies of type Sd have thin disks, while those of type Im are much thicker. After a few comments on modified Newtonian dynamics and on irregular galaxies, I close with statistics on the HI extent of galaxies.Comment: 38 pages, 17 figures, invited review, book chapter in "Outskirts of Galaxies", Eds. J. H. Knapen, J. C. Lee and A. Gil de Paz, Astrophysics and Space Science Library, Springer, in pres

Association of TMTC2 with human nonsyndromic sensorineural hearing loss

IMPORTANCE: Sensorineural hearing loss (SNHL) is commonly caused by conditions that affect cochlear structures or the auditory nerve, and the genes identified as causing SNHL to date only explain a fraction of the overall genetic risk for this debilitating disorder. It is likely that other genes and mutations also cause SNHL. OBJECTIVE: To identify a candidate gene that causes bilateral, symmetric, progressive SNHL in a large multigeneration family of Northern European descent. DESIGN, SETTING, AND PARTICIPANTS: In this prospective genotype and phenotype study performed from January 1, 2006, through April 1, 2016, a 6-generation family of Northern European descent with 19 individuals having reported early-onset hearing loss suggestive of an autosomal dominant inheritance were studied at a tertiary academic medical center. In addition, 179 unrelated adult individuals with SNHL and 186 adult individuals reporting nondeafness were examined. MAIN OUTCOMES AND MEASURES: Sensorineural hearing loss. RESULTS: Nine family members (5 women [55.6%]) provided clinical audiometric and medical records that documented hearing loss. The hearing loss is characterized as bilateral, symmetric, progressive SNHL that reached severe to profound loss in childhood. Audiometric configurations demonstrated a characteristic dip at 1000 to 2000 Hz. All affected family members wear hearing aids or have undergone cochlear implantation. Exome sequencing and linkage and association analyses identified a fully penetrant sequence variant (rs35725509) on chromosome 12q21 (logarithm of odds, 3.3) in the TMTC2 gene region that segregates with SNHL in this family. This gene explains the SNHL occurrence in this family. The variant is also associated with SNHL in a cohort of 363 unrelated individuals (179 patients with confirmed SNHL and 184 controls, P = 7 x 10-4). CONCLUSIONS AND RELEVANCE: A previously uncharacterized gene, TMTC2, has been identified as a candidate for causing progressive SNHL in humans. This finding identifies a novel locus that causes autosomal dominant SNHL and therefore a more detailed understanding of the genetic basis of SNHL. Because TMTC2 has not been previously reported to regulate auditory function, the discovery reveals a potentially new, uncharacterized mechanism of hearing loss

Project-based learning - area of improving the quality of school

U traženju najboljih načina za ostvarivanje ciljeva nastave, jedno od mogućih didaktičkih rješenja pronalazimo u projektnoj nastavi. Ravitz i sur. (2012) opisuju projektnu nastavu kao koncept stvaranja uvjeta u kojima učenici mogu učiti složenija znanja i vještine koja su im nepohodna za život u 21. stoljeću. Ona predstavlja brojne izazove za učitelje i škole, a poteškoće na koje nailaze pri njezinoj implementaciji su brojne. Za učinkovito rješavanje problema implementacije projektne nastave u radu škole, neophodno je omogućiti učiteljima samovrednovanje nastavnog procesa. Samovrednovanje je proces koji sustavno prati, analizira i procjenjuje uspješnost rada kako bi se trajno unaprijedila kvaliteta i stvorilo poticajno radno okruženje. U ovom je radu prikazan primjer Školskog razvojnog plana, kao sastavnog dijela procesa samovrednovanja, kojim je projektna nastava definirana kao prioritetno područje unaprjeđenja rada škole i razvojnih ciljeva koji proizlaze iz njih.In finding the best ways to accomplish learning goals one of the possible didactic solutions would be project-based learning. Ravitz et al. (2012) describe project-based learning as a concept that involves creating conditions which would help students learn more complex knowledge and skills vital for the life in the 21st century. This concept holds many challenges for both teachers and schools, and many issues arise in its implementation. The effective solution for the implementation problems of project-based learning in schools necessary involves self-evaluation of the teaching process. Self-evaluation is a process that systematically monitors, analyses and assesses the work performance in order to permanently achieve better quality and create a more productive working surroundings. This paper shows an example of a school development plan, as an integral part of the self-evaluation process, that defines the project-based learning as a priority area in improving the school processes and development goals which derive from them

Soil Organic Carbon and Nitrogen Feedbacks on Crop Yields under Climate Change

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