228 research outputs found

    Perceptions of Reading Instruction

    Get PDF
    It follows that there exists an obvious need for elementary reading programs to be closely articulated with the developing and changing reading requirements of pupils as they progress through the elementary grades. There is an even more obvious need for close cooperation between teachers and administrators in order to implement reading programs that meet pupil requirements

    Storage and evolution of mafic and intermediate alkaline magmas beneath ross Island, Antarctica

    Get PDF
    We present the results of phase equilibrium experiments carried out on basanite and phonotephrite lavas from Ross Island, Antarctica. Experiments were designed to reproduce the P-T-X-fO₂ conditions of deep and intermediate magma storage and to place constraints on the differentiation of each of the two predominant lava suites on the island, which are thought to be derived from a common parent melt. The Erebus Lineage (EL) consists of lava erupted from the Erebus summit and the Dry Valley Drilling Project (DVDP) lineage is represented by lavas sampled by drill core on Hut Point Peninsula. Experiments were performed in internally heated pressure vessels over a range of temperatures (1000-1150°C) and pressures (200-400 MPa), under oxidized conditions (NNO to NNO+3, where NNO is the nickel-nickel oxide buffer), with X_Η2O of the H₂O-CO₂ mixture added to the experimental capsule varying between zero and unity. The overall mineralogy and mineral compositions of the natural lavas were reproduced, suggesting oxidizing conditions for the deep magma plumbing system, in marked contrast to the reducing conditions (QFM to QFM -1, where QFM is the quartz-fayalite-magnetite buffer) in the Erebus lava lake. In basanite, crystallization of spinel is followed by olivine and clinopyroxene olivine is replaced by kaersutitic amphibole below 1050°C at intermediate water contents. In phonotephrite, the liquidus phase is kaersutite except in runs with low water content (XH₂O^fluid <0·2) where it is replaced by clinopyroxene. Experimental kaersutite compositions suggest that the amphibole-bearing DVDP lavas differentiated below 1050°C at 200-400MPa and NNO+1·5 to NNO+2. Olivine- and clinopyroxene-bearing EL lavas are consistent with experiments performed above 1050°C and pressures around 200 MPa. The plagioclase liquidus at <1-2 wt % H₂O suggests extremely dry conditions for both lineages (XH₂O^fluid approaching zero for EL,∌0·25 for DVDP), probably facilitated by dehydration induced by a CO₂-rich fluid phase. Our results agree with previous studies that suggest a single plumbing system beneath Ross Island in which DVDP lavas (and probably other peripheral volcanic products) were erupted through radial fractures associated with the ascent of parental magma into the lower crust. The longer travel time of the DVDP lavas through the crust owing to lateral movement along fractures and the lack of a direct, sustained connection to the continuous CO₂-rich gas flux that characterizes the main central Erebus conduit is probably responsible for the lower temperatures and slightly wetter conditions and hence the change in mineralogy observed.Fieldwork in Antarctica was supported by the Office of Polar Programs (National Science Foundation) (ANT1142083). Experimental research was supported by Labex Voltaire (ANR-10-LABX-100-10); and by the University of Cambridge Department of Geography Phillip Lake and William Vaughn Lewis grants

    Ocular manifestations in Gorlin-Goltz syndrome

    Get PDF
    Background: Gorlin-Goltz syndrome, also known as nevoid basal cell carcinoma syndrome, is a rare genetic disorder that is transmitted in an autosomal dominant manner with complete penetrance and variable expressivity. It is caused in 85% of the cases with a known etiology by pathogenic variants in the PTCH1 gene, and is characterized by a wide range of developmental abnormalities and a predisposition to multiple neoplasms. The manifestations are multiple and systemic and consist of basal cell carcinomas in various regions, odontogenic keratocistic tumors and skeletal anomalies, to name the most frequent. Despite the scarce medical literature on the topic, ocular involvement in this syndrome is frequent and at the level of various ocular structures. Our study focuses on the visual apparatus and its annexes in subjects with this syndrome, in order to better understand how this syndrome affects the ocular system, and to evaluate with greater accuracy and precision the nature of these manifestations in this group of patients. Results: Our study confirms the presence of the commonly cited ocular findings in the general literature regarding the syndrome [hypertelorism (45.5%), congenital cataract (18%), nystagmus (9%), colobomas (9%)] and highlights strabismus (63% of the patients), epiretinal membranes (36%) and myelinated optic nerve fiber layers (36%) as the most frequent ophthalmological findings in this group of patients. Conclusions: The presence of characteristic and frequent ocular signs in the Gorlin- Goltz syndrome could help with the diagnostic process in subjects suspected of having the syndrome who do not yet have a diagnosis. The ophthalmologist has a role as part of a multidisciplinary team in managing these patients. The ophthalmological follow-up that these patients require, can allow, if necessary, a timely therapy that could improve the visual prognosis of such patients

    Damage Detection and Localization on Real Structures Subjected to Strong Motion Earthquakes Using the Curvature Evolution Method: The Navelli (Italy) Case Study

    Get PDF
    In recent years, structural health monitoring (SHM) has received increasing interest from both research and professional engineering communities. This is due to the limitations related to the use of traditional methods based on visual inspection for a rapid and effective assessment of structures and infrastructures when compared with the great potential offered by newly developed automatic systems. Most of these kinds of systems allow the continuous estimation of structural modal properties that are strictly correlated to the mechanical characteristics of the monitored structure. These can change as a result of material deterioration and structural damage related to earthquake shaking. Furthermore, a suitable configuration of a dense sensor network in a real-time monitoring system can allow to detect and localize structural and non-structural damage by comparing the initial and a final state of the structure after a critical event, such as a relevant earthquake. In this paper, the modal curvature evaluation method, used for damage detection and localization on framed structures, considering the mode curvature variation due to strong earthquake shaking, is further developed. The modified approach is validated by numerical and experimental case studies. The extended procedure, named "Curvature Evolution Method" (CEM), reduces the required computing time and the uncertainties in the results. Furthermore, in this work, an empirical relationship between curvature variation and damage index has been defined for both bare and infilled frames

    Assessing Vegetation Decline Due to Pollution from Solid Waste Management by a Multitemporal Remote Sensing Approach

    Get PDF
    Nowadays, the huge production of Municipal Solid Waste (MSW) is one of the most strongly felt environmental issues. Consequently, the European Union (EU) delivers laws and regulations for better waste management, identifying the essential requirements for waste disposal operations and the characteristics that make waste hazardous to human health and the envi-ronment. In Italy, environmental regulations define, among other things, the characteristics of sites to be classified as “potentially contaminated”. From this perspective, the Basilicata region is cur-rently one of the Italian regions with the highest number of potentially polluted sites in proportion to the number of inhabitants. This research aimed to identify the possible effects of potentially toxic element (PTE) pollution due to waste disposal activities in three “potentially contaminated” sites in southern Italy. The area was affected by a release of inorganic pollutants with values over the thresholds ruled by national/European legislation. Potential physiological efficiency variations of vegetation were analyzed through the multitemporal processing of satellite images. Landsat 5 Thematic Mapper (TM) and Landsat 8 Operational Land Imager (OLI) images were used to calcu-late the trend in the Normalized Difference Vegetation Index (NDVI) over the years. The mul-titemporal trends were analyzed using the median of the non-parametric Theil–Sen estimator. Fi-nally, the Mann–Kendall test was applied to evaluate trend significance featuring areas according to the contamination effects on investigated vegetation. The applied procedure led to the exclu-sion of significant effects on vegetation due to PTEs. Thus, waste disposal activities during previ-ous years do not seem to have significantly affected vegetation around targeted sites

    Reconciling complex stratigraphic frameworks reveals temporally and geographically variable depositional patterns of the Campanian Ignimbrite

    Get PDF
    The 39.8-ka Campanian Ignimbrite was emplaced during a large caldera-forming eruption of Campi Flegrei near Naples, Italy. The ignimbrite is found up to 80 km from the caldera, and co-ignimbrite ash-fall deposits occur 3200 km away. The proximal and distal stratigraphy of the Campanian Ignimbrite has not been definitively correlated due to the dissimilar appearance of the proximal and distal deposits, a lack of medial exposures, and the inconsistency and heterogeneity of the proximal stratigraphy. Here, we document the major-element glass-shard chemistry, matrix componentry, and lithic componentry of the proximal and distal stratigraphic sequences of the ignimbrite to attempt to correlate the units. The results of these disparate observations taken together suggest that the established stratigraphic units cannot be directly and uniquely correlated between the proximal and distal regions and that neither the proximal nor distal stratigraphy provides a record of the entire eruptive sequence. However, the characteristics studied can be used to demarcate eruptive phases that are connected to some of the defined units in the proximal and distal stratigraphy

    Reconstruction of phrenic neuron identity in embryonic stem cell-derived motor neurons

    Get PDF
    Air breathing is an essential motor function for vertebrates living on land. The rhythm that drives breathing is generated within the central nervous system and relayed via specialised subsets of spinal motor neurons to muscles that regulate lung volume. In mammals, a key respiratory muscle is the diaphragm, which is innervated by motor neurons in the phrenic nucleus. Remarkably, relatively little is known about how this crucial subtype of motor neuron is generated during embryogenesis. Here, we used direct differentiation of motor neurons from mouse embryonic stem cells as a tool to identify genes that direct phrenic neuron identity. We find that three determinants, Pou3f1, Hoxa5 and Notch, act in combination to promote a phrenic neuron molecular identity. We show that Notch signalling induces Pou3f1 in developing motor neurons in vitro and in vivo. This suggests that the phrenic neuron lineage is established through a local source of Notch ligand at mid-cervical levels. Furthermore, we find that the cadherins Pcdh10, which is regulated by Pou3f1 and Hoxa5, and Cdh10, which is controlled by Pou3f1, are both mediators of like-like clustering of motor neuron cell bodies. This specific Pcdh10/Cdh10 activity might provide the means by which phrenic neurons are assembled into a distinct nucleus. Our study provides a framework for understanding how phrenic neuron identity is conferred and will help to generate this rare and inaccessible yet vital neuronal subtype directly from pluripotent stem cells, thus facilitating subsequent functional investigations

    Evidence for partial melt in the crust beneath Mt. Paektu (Changbaishan), Democratic People's Republic of Korea and China

    Get PDF
    Mt. Paektu (also known as Changbaishan) is an enigmatic volcano on the border between the Democratic People's Republic of Korea (DPRK) and China. Despite being responsible for one of the largest eruptions in history, comparatively little is known about its magmatic evolution, geochronology, or underlying structure. We present receiver function results from an unprecedented seismic deployment in the DPRK. These are the first estimates of the crustal structure on the DPRK side of the volcano and, indeed, for anywhere beneath the DPRK. The crust 60 km from the volcano has a thickness of 35 km and a bulk VPV_\text{P}/VSV_\text{S} of 1.76, similar to that of the Sino-Korean craton. The VPV_\text{P}/VSV_\text{S} ratio increases ~20 km from the volcano, rising to >1.87 directly beneath the volcano. This shows that a large region of the crust has been modified by magmatism associated with the volcanism. Such high values of VPV_\text{P}/VSV_\text{S} suggest that partial melt is present in the crust beneath Mt. Paektu. This region of melt represents a potential source for magmas erupted in the last few thousand years and may be associated with an episode of volcanic unrest observed between 2002 and 2005.This work was supported by the Richard Lounsbery Foundation. The UK seismic instruments and data management facilities were provided under loan number 976 by SEIS-UK at the University of Leicester. The facilities of SEIS-UK are supported by the NERC under Agreement R8/H10/64. J.O.S.H. was supported by an NERC Fellowship NE/I020342/1

    Promising Non-cytotoxic Monosubstituted Chalcones to Target Monoamine Oxidase-B

    Get PDF
    A library of monosubstituted chalcones (1-17) bearing electron-donating and electron-withdrawing groups on both aromatic rings were selected. The cell viability on human tumor cell lines was evaluated first. The compounds unable to induce detectable cytotoxicity (1, 13, and 14) were tested using the monoamine oxidase (MAO) activity assay. Interestingly, they inhibit MAO-B, acting as competitive inhibitors, with 13 and 14 showing the best profiles. In particular, 13 exhibited a potency higher than that of safinamide, taken as a reference. Docking studies and crystallographic analysis showed that in human MAO-B 13 binds with the halogen-substituted aromatic ring in the entrance cavity, similar to safinamide, whereas 14 is accommodated in the opposite way. The main conclusion of this cell biology, biochemistry, and structural study is to highlights 13 as a chalcone derivative that is worth consideration for the development of novel MAO-B-selective inhibitors for the treatment of neurodegenerative diseases

    Quantifying gas emissions from the "Millennium Eruption" of Paektu volcano, Democratic Peoples Republic of Korea/China

    Get PDF
    Paektu volcano (Changbaishan) is a rhyolitic caldera that straddles the border between the Democratic People’s Republic of Korea and China. Its most recent large eruption was the Millennium Eruption (ME; 23 km3^{3} dense rock equivalent) circa 946 CE, which resulted in the release of copious magmatic volatiles (H2_{2}O, CO2_{2}, sulfur, and halogens). Accurate quantification of volatile yield and composition is critical in assessing volcanogenic climate impacts but is challenging, particularly for events before the satellite era. We use a geochemical technique to quantify volatile composition and upper bounds to yields for the ME by examining trends in incompatible trace and volatile element concentrations in crystal-hosted melt inclusions. We estimate that the ME could have emitted as much as 45 Tg of S to the atmosphere. This is greater than the quantity of S released by the 1815 eruption of Tambora, which contributed to the “year without a summer.” Our maximum gas yield estimates place the ME among the strongest emitters of climate-forcing gases in the Common Era. However, ice cores from Greenland record only a relatively weak sulfate signal attributed to the ME. We suggest that other factors came into play in minimizing the glaciochemical signature. This paradoxical case in which high S emissions do not result in a strong glacial sulfate signal may present a way forward in building more https://symplectic.admin.cam.ac.uk/objectedit.html?cid=1&oid=876954generalized models for interpreting which volcanic eruptions have produced large climate impacts.K.I. was supported by the NSF under award no. 1349486 and by AAAS. Fieldwork was supported by the Richard Lounsbery Foundation
    • 

    corecore