Readability and Parent Communications: Can Parents Understand What Schools Write to Them?

As for Americans in their early 20s, the National Assessment of Education Progress found in 1985 that 6 percent could not read as well as the average 4th grader and 20 percent could not read as well as an 8th grader ( 20% of Young Americans, 1986). Therefore, it seems reasonable to assume that a significant number of parents in these school programs for educationally disadvantaged children are unable to read the communications sent to them by the schools

Suggestions for Improving the Language Development of Disabled Secondary Readers

As high school teachers of reading and English know, some students in their classrooms are poor in all areas of language. They read on a fourth-grade level; they write and spell so as to obscure most communication; they speak in simple sentences; their listening ability is so low that they can\u27t seem to follow most directions. What can we do to fill in the innumerable gaps in all these areas? It is the purpose of this article to present two ways to improve a student\u27s level of language development: 1) daily exposure to good literature in the original (not adapted to a fourth grade level) and 2) daily lessons in syntactical manipulation and sentence combining, including the use of language games

Carbonatitic versus hydrothermal origin for fluorapatite REE-Th deposits: Experimental study of REE transport and crustal “antiskarn” metasomatism

Nolans-type ore deposits contain REE and Th mineralization hosted in fluorapatite veins. These veins intrude granulite facies rocks and are surrounded by a diopside selvage. Nolans-type deposits are thought to form by REE, F and P-rich hydrothermal fluids derived from alkali or carbonatitic intrusions. However, REE are not effectively transported in F and P-rich systems. REE ore deposits are commonly hydrothermally overprinted, possibly obscuring the igneous nature of the primary mineralization. We conducted a series of piston cylinder “sandwich” experiments, testing the hydrothermal fluid hypothesis, and a newly suggested process of carbonatite metasomatism. Our results confirm theoretical predictions that REE are hydrothermally immobile in these systems and the experimental phase assemblage is not compatible with the natural rocks. Our results show that fluorapatite can only host several weight percent levels of REE at temperatures higher than ∼600 °C. Below that temperature, a miscibility gap exists between REE-poor fluorapatite and REE-rich silicates such as britholite or cerite. In contrast, experiments reacting P and REE-rich carbonatite with silicate rock above 700 °C closely resemble natural rocks from Nolans-type deposits. Selvage mineralogy is sensitive to the MgO content of the carbonatite. A diopside selvage formed at carbonatite MgO/(CaO+MgO) ≈ 0.2 while wollastonite and forsterite formed at lower and higher ratios, respectively. Phosphate solubility in carbonatites decreases with decreasing MgO contents. As diopside formed, REE-rich fluorapatite preferentially crystallized from the selvage inwards. Thus, carbonatites are effective at simultaneously mobilizing REE, F and P to the site of deposition. Nolans-type deposits are the cumulate residue of this reaction, with the carbonatite liquid migrating elsewhere. At temperatures below 700 °C the carbonatite–silicate reaction additionally formed monticellite, cuspidine and magnesioferrite, resembling a skarn assemblage. Whereas skarns form by infiltration of silicate magmas or related fluids to carbonate rocks, our experiments are the opposite: intrusion of carbonatite into silicate rock. These mid-crustal skarn-like rocks may host elevated ore elements of carbonatitic affinity, such as F, P, Y, REE, Th, Ba, Sr, and Nb. We propose the term “antiskarn” to describe such systems, and suggest they trace the migration of carbonatite liquids through the crust. Hydrothermal reworking, retrogression, or metamorphism of antiskarns may obscure the carbonatitic genesis of the rocks. These metasomatic zones are the crustal equivalent of wehrlites that form by peridotite–carbonatite reaction at mantle depths.This research is supported by an Australian Government Research Training Program (RTP) Scholarship. Michael Anenburg acknowledges a Ringwood Scholarship from the Research School of Earth Sciences, Australian National University

Controls on Gold Solubility in Arc Magmas: An Experimental Study at 1000°C and 4 kbar

International audienceIn order to (1), explain the worldwide association between epithermal gold-copper-molybdenum deposits and arc magmas and (2), test the hypothesis that adakitic magmas would be Au-specialized, we have determined the solubility of Au at 4 kbar and 1000°C for three intermediate magmas (two adakites and one calc-alkaline composition) from the Philippines. The experiments were performed over a fO2 range corresponding to reducing (not, vert, similarNNO-1), moderately oxidizing (not, vert, similarNNO+1.5) and strongly oxidizing (not, vert, similarNNO+3) conditions as measured by solid Ni-Pd-O sensors. They were carried out in gold containers, the latter serving also as the source of gold, in presence of variable amounts of H2O and, in a few additional experiments, of S. Concentrations of Au in glasses were determined by LA-ICPMS. Gold solubility in melt is very low (30-240 ppb) but increases with fO2 in a way consistent with the dissolution of gold as both Au1+ and Au3+ species. In the S-bearing experiments performed at not, vert, similarNNO-1, gold solubility reaches much higher values, from not, vert, similar1200 to 4300 ppb, and seems to correlate with melt S content. No systematic difference in gold solubility is observed between the adakitic and non-adakitic compositions investigated. Oxygen fugacity and the sulfur concentration in melt are the main parameters controlling the incorporation and concentration of gold in magmas. Certain adakitic and non-adakitic magmas have high fO2 and magmatic S concentrations favorable to the incorporation and transport of gold. Therefore, the cause of a particular association between some arc magmas and Au-Cu-Mo deposits needs to be searched in the origin of those specialized magmas by involvement of Au- and S-rich protoliths. The subducted slab, which contains metal-rich massive sulfides, may constitute a potentially favorable protolith for the genesis of magmas specialized with respect to gold

Experimental evidence of sulfide melt evolution via immiscibility and fractional crystallization

Most ore deposits in high-grade metamorphic terranes show signs of remobilization of sulfide ores. During this process the compositions and tenor of the ore change dramatically. In this report we show the results of a study designed to clarify chemical modification of sulfide melts as they cool from high temperatures. Sulfide melts were allowed to "trickle down" through a permeable inert host over an extreme temperature gradient. The effects of crystal fractionation and liquid immiscibility can be clearly seen in the resultant experimental charges, explaining many features previously documented in metamorphosed ores

Sulfur isotope and trace element systematics of zoned pyrite crystals from the El Indio Au-Cu-Ag deposit, Chile

We present a comparative study between early, massive pyrite preceding (Cu–Ag) sulfosalt mineralization in high-temperature feeder zones (‘early pyrite’) and late pyrite that formed during silicic alteration associated with Au deposition (‘late pyrite’) at the El Indio high-sulfidation Au–Ag–Cu deposit, Chile. We use coupled in situ sulfur isotope and trace element analyses to chronologically assess geochemical variations across growth zones in these pyrite crystals. Early pyrite that formed in high-temperature feeder zones shows intricate oscillatory zonation of Cu, with individual laminae containing up to 1.15 wt% Cu and trace Co, As, Bi, Ni, Zn, Se, Ag, Sb, Te, Au, Pb and Bi. Late pyrite formed after (Cu–Ag) sulfosalt mineralization. It contains up to 1.14 wt% As with trace Cu, Zn, Pb, V, Mn, Co, Ni, Ge, Se, Ag, Sb, Te, Pb and Bi, as well as colloform Cu-rich growth bands containing vugs toward the outer edges of some crystals. Plotting the trace element data in chronological order (i.e., from core to rim) revealed that Co and Ni were the only elements to consistently co-vary across growth zones. Other trace elements were coupled in specific growth zones, but did not consistently co-vary across any individual crystal. The δ34S of early pyrite crystals in high-temperature feeder zones range from −3.19 to 1.88 ‰ (±0.5 ‰), consistent with sublimation directly from a high-temperature magmatic vapor phase. Late pyrite crystals are distinctly more enriched in δ34S than early pyrite (δ34S = 0.05–4.77 ‰, ±0.5 ‰), as a consequence of deposition from a liquid phase at lower temperatures. It is unclear whether the late pyrite was deposited from a small volume of liquid condensate, or a larger volume of hydrothermal fluid. Both types of pyrite exhibit intracrystalline δ34S variation, with a range of up to 3.31 ‰ recorded in an early pyrite crystal and up to 4.48 ‰ in a late pyrite crystal. Variations in δ34Spyrite at El Indio did not correspond with changes in trace element geochemistry. The lack of correlation between trace elements and δ34S, as well as the abundance of microscale mineral inclusions and vugs in El Indio pyrite indicate that the trace element content of pyrite at El Indio is largely controlled by nanoscale, syn-depositional mineral inclusions. Co and Ni were the only elements partitioned within the crystal structure of pyrite. Cu-rich oscillatory zones in early pyrite likely formed by nanoscale inclusions of Cu-rich sulfosalts or chalcopyrite, evidence of deposition from a fluid cyclically saturated in ore metals. This process may be restricted to polymetallic high-sulfidation-like deposits

The importance of talc and chlorite "hybrid” rocks for volatile recycling through subduction zones; evidence from the high-pressure subduction mélange of New Caledonia

The transfer of fluid and trace elements from the slab to the mantle wedge cannot be adequately explained by simple models of slab devolatilization. The eclogite-facies mélange belt of northern New Caledonia represents previously subducted oceanic crust and contains a significant proportion of talc and chlorite schists associated with serpentinite. These rocks host large quantities of H2O and CO2 and may transport volatiles to deep levels in subduction zones. The bulk-rock and stable isotope compositions of talc and chlorite schist and serpentinite indicate that the serpentinite was formed by seawater alteration of oceanic lithosphere prior to subduction, whereas the talc and chlorite schists were formed by fluid-induced metasomatism of a mélange of mafic, ultramafic and metasedimentary rocks during subduction. In subduction zones, dehydration of talc and chlorite schists should occur at sub-arc depths and at significantly higher temperatures (∼ 800°C) than other lithologies (400-650°C). Fluids released under these conditions could carry high trace-element contents and may trigger partial melting of adjacent pelitic and mafic rocks, and hence may be vital for transferring volatile and trace elements to the source regions of arc magmas. In contrast, these hybrid rocks are unlikely to undergo significant decarbonation during subduction and so may be important for recycling carbon into the deep mantl

The focusing properties of the positron-capture solenoidal lens

This note concerns the focusing properties of the positron-capture solenoid. Such a solenoid will be placed before the entrance of the 450 MeV positron linear-accelerator injector in the APS. The 1.25 A, 40 ns electron beam is accelerated in the 200 MeV electron linac. This beam is then focused onto a 3 mm diameter spot at the 7 mm thick tungsten target. By the process of multiple nuclear-scattering the target generates the positron particles. These positrons, in general, can have a large diverging angle. In order to capture these rapidly diverging positrons, a relatively strong focusing lens is placed close to the converter. In this case a magnetic solenoidal lens has an advantage over the usual quadrupole lens because of its larger phase-space acceptance. In particular, the solenoidal lens is noted for its capability of controlling the spin direction of polarized ions. The authors first wrote down the expression for the magnetic field distribution on the axis for the solenoidal lens. From this expression they derive the expressions for the first- and second-order field distributions at any point in the region. They then calculate and compare the focal powers at various distances off the axis. Further, they calculate and include the third- and fourth-order components of the fields and compare them with the previous results. Finally, they briefly consider the particle trajectories through these fields and present the result in terms of the particle motion in phase space

Silicate-sulfide liquid immiscibility in modern arc basalt (Tolbachik volcano, Kamchatka): Part I. Occurrence and compositions of sulfide melts

Silicate-sulfide liquid immiscibility plays a key role in the formation of magmatic sulfide ore deposits but incipient sulfide melts are rarely preserved in natural rocks. This study presents the distribution and compositions of olivine-hosted sulfide melt globules resulting from silicate-sulfide liquid immiscibility in primitive arc basalts. Abundant sulfide droplets entrapped in olivine from primitive basalts of the 1941 eruption and pre-historic eruptive cone “Mt. 1004” of the Tolbachik volcano, Kurile-Kamchatka arc. Inclusions range from submicron to 250 μm in size, coexist with sulfur-rich glass (≤ 1.1 wt% S), and, in some cases, with magmatic anhydrite. Saturation in sulfide occurred early in the evolution of a water- and sulfur-rich magma, moderately oxidized (QFM + 1 to +1.5), which crystallized high-Mg olivine (Fo₈₆ˍ₉₂), clinopyroxene and Cr-spinel. The process developed dense “clouds” of sulfide in relatively small volumes of magma, with highly variable abundances of chalcophile metals. The low degree of sulfide supersaturation promoted diffusive equilibration of the growing droplets with the melt in Ni and Cu, resulting in high concentrations (≈ 38 mol%) of CuS and NiS in the earliest sulfide liquids. The Tolbachik samples provide a glimpse into deep arc processes not seen elsewhere, and may show how arc magmas, despite their oxidized nature, saturate in sulfide.This study was supported by the Russian Science Foundation grant # 16-17-10145. This is CRPG contribution #253