Glaciochemical Investigations as a Tool in the Historical Delineation of the Acid Precipitation Problem

Precipitation in the Northern Hemisphere has been recently recognized to have hydrogen ion concentrations 10 to 100 times higher than expected for natural precipitation (Likens and Bormann 1974, Cogbill and Likens 1974, Lewis and Grant 1980). However, controversy has arisen regarding the nature of the acidity of the precipitation sampled and whether, indeed, the pH of North American precipitation has increased over time (Miller and Everett 1979, Lerman 1979, Stensland 1980, Sequeria 1981, Carlson and Rodhe 1982). In most locations pH records have been constructed rather imperfectly due to differences in sampling, handling, and analytical procedures used (Galloway and Likens 1976, 1978; Galloway et al. 1979). The lower pH\u27s measured in Northern Hemisphere precipitation are thought to be due to the input of sulfur and nitrogen oxides from fossil fuel-burning (Likens and Bormann 1974) and in some cases hydrogen chloride (Gorham 1958a). Few baseline data, however, are available on the pH of precipitation in areas of the Northern Hemisphere remote from North American and European sources of anthropogenic sulfur emissions. In addition, monitoring records of pH and acidic chemical species are of rather short time duration (~ 15 to 20 years at most), limited geographic coverage, and provide little useful information prior to the early 1960’s (Hornbeck 1981). Baseline studies of pH and related chemical species as well as historical time series data are warranted if they are to understand man’s effect on the environment. The National Academy of Sciences (1978) recommends that historical studies of glacier snow and ice should be conducted. Such studies are needed to better understand the atmospheric transport of anthropogenically-introduced chemical species to remote areas. In addition, a more recent NAS report (1980) states that a major scientific goal of the 1980’s should be to “identify the significant natural and anthropogenic factors contributing to acid rain.” Detailed glacio-chemical studies should provide this type of needed information. Snow and ice cores collected from appropriately chosen glaciers provide samples of entrapped chemical species that, unlike those derived from any other medium, are nearly-to- entirely unaltered since their deposition. This technique has barely been applied to the study of acid precipitation despite the fact that it provides a very sensitive record of precipitation chemistry

Stellar Reaction Rates for ^(28)Si

Stellar rates for the reactions ^(27)Al(p,-y)^(28)Si and ^(24)Mg(ɑ,-y)^(28)Si have been calculated from new cross- section data for these reactions. The contributions to the interaction rates, (σv)_(py) and (σv)_(ay), and to the corresponding photodisintegration rates, λ_(yp) and λ_(ya), from the excited states of ^(27)Al, ^(24)Mg, and ^(28)Si are discussed. The calculated interaction rates, N_A(σv), are listed for temperatures from 0.1 X 10^9º to 5.0 X 10^9° K; two- and four-parameter fits are given for N_A(σv) as a function of temperature

A highly solvated zinc(II) tetrakis(pentafluorophenyl)-β-octabromoporphyrin

The title compound, {4,5,9,10,14,15,19,20-octabromo-2,7,12,17-tetrakis(pentafluorophenyl)-21,22,23,- 24-tetraazapentacyclo[16.2.1.1^(3,6).1^(8,11).1^(13,16)]tetracosa-1,3(21),4,6,8(22),9,11,13(23),14,16,18(24),19-dodecaene }zinc(II) (carbon tetrachloride, o-dichlorobenzene, acetone, methanol, water solvate) has a large tetrahedral distortion, with the Br atoms as much as 1.83 Å from the plane of the N atoms. The distortion affects primarily bond angles and bond torsion angles; bond distances in the molecule are normal. Several different solvents are incorporated into the crystal, providing a close (2.16 Å) O atom as an axial neighbor to Zn and a more distant (3.16 Å) Cl atom, in the opposite axial site

Copper(II) and Nickel(II) Octabromo-tetrakis(pentafluorophenyl)Porphyrin Complexes

The copper and nickel complexes of 2,3,7,8,12,13,17, 18-octabromo-5,10,15,20-tetrakis(pentaftuorophenyl) porphyrin ({4,5,9,10,14,15,19,20-octabromo-2,7,12,17-tetrakis(pentaftuorophenyl)-21,22,23,24-tetraazapentacyclo[l6.2.1.1^(3,6).l^(8,11).l^(13,16)]tetracosa-l,3-(22),4,6,8(23),9,11,13(24),14,16,18(21),19-dodecaene }copper(II) 0.5-dichloromethane solvate and {4,5,9,10,14,15,19,20-octabromo-2,7,12,17-tetrakis(pentaftuorophenyl)-21,22,23,24-tetraazapentacyclo( 16.2.1.1^(3,6).l^(8,11).l^(13,16)]tetracosa-l,3(22),4,6,8(23),9,ll,13(24),14,16,18(21),19-dodecaene} nickel(II)0.5-dichloromethane solvate) form isostructural crystals. There is significant distortion from planarity of the porphyrin ring caused by the octabromo substituents interacting with the meso-pentafluorophenyl groups and with each other, with departures of the Br atoms from the plane defined by the four N atoms of up to 2.36 A. This tetrahedral distortion of the molecule does not result in any significant changes in bond distances from those in non-halogenated tetraphenylporphyrin complexes

Copper(II) tetrakis(pentafluorophenyl)-β-octachloroporphyrin

The title compound, {4,5,9,10,14,15,19,20-octachloro-2,7,12, 17-tetrakis(pentafluorophenyl)-20,22,23,24- tetraazapentacyclo[l6.2.l.1^(3·6).l^(8·11).l^(13·16)]tetracosa-1,3(21),4,6,8(22),9,11, 13(23), 14, 16, 18(24), 19-dodecaene}copper(II)(CuTFPPC1_8)dichloromethane solvate, shows a large tetrahedral distortion or ruffling, with pairs of Cl atoms alternately averaging + 1.20 and -1.18 Å out of the plane of the four N atoms; the Cu atom is 0.01 Å out of the plane and the N atoms show a slight (±0.12 Å) tetrahedral distortion. A Cl atom of the solvent, at 3.515 (6) Å in an approximately axial position, is the closest non-bonded neighbor of the Cu atom

The Race to Leadership Effectiveness: A Study on School Organization for High and Low Performing Georgia Schools

With the adoption of such initiatives as No Child Left Behind (NCLB), Common Core State Standards (CCSS), and the College and Career Readiness Performance Index (CCRPI), there is increasing pressure for students to meet and exceed performance expectations. This is easier said than done, especially given that not all organizational structures are helpful to student performance. A quantitative, correlational study was done to determine the relationship between school organization and school performance within Georgia schools. Subgroup comparisons between high and low performing schools were included in analyses. Results showed that high organizational effectiveness was associated with high student performance outcomes. High performing schools had significantly higher organizational effectiveness than low performing schools. The findings of this study help teachers, administrators, and policy makers determine essential organizational themes that help students succeed. The use of positive organizational characteristics is encouraged in order for students to have much better success moving forward

Therapist effects in outpatient psychotherapy: A three-level growth curve approach

Evidence suggests that a moderate amount of variance in patient outcomes is attributable to therapist differences. However, explained variance estimates vary widely, perhaps because some therapists achieve greater success with certain kinds of patients. This study assessed the amount of variance in across-session change in symptom intensity scores explained by therapist differences in a large naturalistic data set (1,198 patients and 60 therapists, who each treated 10 -77 of the patients). Results indicated that approximately 8% of the total variance and approximately 17% of the variance in rates of patient improvement could be attributed to the therapists. Cross-validation and extreme group analyses validated the existence of these therapist effects

Manipulation of Fgf and Bmp signaling in teleost fishes suggests potential pathways for the evolutionary origin of multicuspid teeth

Teeth with two or more cusps have arisen independently from an ancestral unicuspid condition in a variety of vertebrate lineages, including sharks, teleost fishes, amphibians, lizards, and mammals. One potential explanation for the repeated origins of multicuspid teeth is the existence of multiple adaptive pathways leading to them, as suggested by their different uses in these lineages. Another is that the addition of cusps required only minor changes in genetic pathways regulating tooth development. Here we provide support for the latter hypothesis by demonstrating that manipulation of the levels of Fibroblast growth factor (Fgf) or Bone morphogenetic protein (Bmp) signaling produces bicuspid teeth in the zebrafish (Danio rerio), a species lacking multicuspid teeth in its ancestry. The generality of these results for teleosts is suggested by the conversion of unicuspid pharyngeal teeth into bicuspid teeth by similar manipulations of the Mexican Tetra (Astyanax mexicanus). That these manipulations also produced supernumerary teeth in both species supports previous suggestions of similarities in the molecular control of tooth and cusp number. We conclude that despite their apparent complexity, the evolutionary origin of multicuspid teeth is positively constrained, likely requiring only slight modifications of a pre-existing mechanism for patterning the number and spacing of individual teeth. © 2013 Wiley Periodicals, Inc