By a Thread: The New Experience of America's Middle Class

Developed in collaboration with the Institute on Assets and Social Policy at Brandeis University, By a Thread: The New Experience of America's Middle Class looks at the financial security of the middle class using the innovative Middle Class Security Index, rating household stability across five core economic factors: assets, educational achievement, housing costs, budget and healthcare. The Index provides a comprehensive portrait of how well middle-class families are faring in each of these areas, with spotlight on the strengths and vulnerabilities of today's middle class

Economic (In)Security: The Experience of the African-American and Latino Middle Classes

As the next installment in the By a Thread series, Economic (In)Security uses the Middle Class Security Index to provide the first comprehensive portrait of the level of financial security enjoyed by African-American and Latino middle-class families. The findings show that, in the wake of fading economic opportunity, these two rapidly growing groups face mounting obstacles in becoming part of, and remaining securely in, America's middle class

From Middle to Shaky Ground: The Economic Decline of America's Middle Class

A middle-class standard of living requires that families have adequate financial security to meet current obligations, invest in the future, and access opportunities. The most recent findings from the Middle Class Security Index show that between 2000 and 2006--even before the most recent economic downturn--the economic well-being of middle-class families slipped noticeably.Between 2000 and 2006 an estimated 4 million middle-class families lost their financial security, bringing the total number of middle-income families on shaky ground to 23 million.These worrisome changes in the overall financial health of the middle class were driven by a decline in assets, rising housing costs, and a growing lack of health insurance

Energy use for urban water management by utilities and Households in Los Angeles

Reducing energy consumption for urban water management may yield economic and environmental benefits. Few studies provide comprehensive assessments of energy needs for urban water sectors that include both utility operations and household use. Here, we evaluate the energy needs for urban water management in metropolitan Los Angeles (LA) County. Using planning scenarios that include both water conservation and alternative supply options, we estimate energy requirements of water imports, groundwater pumping, distribution in pipes, water and wastewater treatment, and residential water heating across more than one hundred regional water agencies covering over 9 million people. Results show that combining water conservation with alternative local supplies such as stormwater capture and water reuse (nonpotable or indirect potable) can reduce the energy consumption and intensity of water management in LA. Further advanced water treatment for direct potable reuse could increase energy needs. In aggregate, water heating represents a major source of regional energy consumption. The heating factor associated with grid-supplied electricity drives the relative contribution of energy-for-water by utilities and households. For most scenarios of grid operations, energy for household water heating significantly outweighs utility energy consumption. The study demonstrates how publicly available and detailed data for energy and water use supports sustainability planning. The method is applicable to cities everywhere

Automatic Control System for Dispensing Precise Amounts of FInely Divided Solids

A device for automatic dispensing of precise amounts of finely divided solids has been developed. Precision is a function of dispensing time. Smaller than gram quantities may be dispensed at a rate of about 1/3 g/min with a precision corresponding to a weight range of about 0.001 g for a series. The process consists in moving the material with the effect of the vibratory motion of a miniature air-powered vibrator. Operation is automatically controlled by the electronic system of the weighing unit interfaced to the pneumatic dispensing device via a combination fluidic and pneumatic control system

Arc–continent collision and the formation of continental crust : a new geochemical and isotopic record from the Ordovician Tyrone Igneous Complex, Ireland

Author Posting. © Geological Society of London, 2009. This is the author's version of the work. It is posted here by permission of Geological Society of London for personal use, not for redistribution. The definitive version was published in Journal of the Geological Society 166 (2009): 485-500, doi:10.1144/0016-76492008-102.Collisions between oceanic island-arc terranes and passive continental margins are thought to have been important in the formation of continental crust throughout much of Earth’s history. Magmatic evolution during this stage of the plate-tectonic cycle is evident in several areas of the Ordovician Grampian-Taconic Orogen, as we demonstrate in the first detailed geochemical study of the Tyrone Igneous Complex, Ireland. New U–Pb zircon dating yields ages of 493 ± 2 Ma from a primitive mafic intrusion, indicating intra-oceanic subduction in Tremadoc time, and 475 ± 10 Ma from a light-rare-earth-element (LREE)-enriched tonalite intrusion that incorporated Laurentian continental material by early Arenig time (Early Ordovician, Stage 2) during arc-continent collision. Notably, LREE enrichment in volcanism and silicic intrusions of the Tyrone Igneous Complex exceeds that of average Dalradian (Laurentian) continental material which would have been thrust under the colliding forearc and potentially recycled into arc magmatism. This implies that crystal fractionation, in addition to magmatic mixing and assimilation, was important to the formation of new crust in the Grampian-Taconic Orogeny. Because similar super-enrichment of orogenic melts occurred elsewhere in the Caledonides in the British Isles and Newfoundland, the addition of new, highly enriched melt to this accreted arc terrane was apparently widespread spatially and temporally. Such super-enrichment of magmatism, especially if accompanied by loss of corresponding lower crustal residues, supports the theory that arc-continent collision plays an important role in altering bulk crustal composition toward typical values for ancient continental crust.This work was supported by the University of Aberdeen. LA-MC-ICPMS dating was conducted at the Arizona LaserChron Center with the assistance of George Gehrels and Victor Valencia and was supported by NSF-EAR 0443387

Palaeotectonic setting of the south-eastern Kédougou-Kéniéba Inlier, West Africa: new insights from igneous trace element geochemistry and U-Pb zircon ages

New U-Pb zircon ages and geochemistry from the eastern Kédougou-Kéniéba Inlier are presented and integrated with published data to generate a revised tectonic framework for the westernmost Birimian terranes. The Falémé Volcanic Belt and Kofi Series are highly prospective, hosting several multi-million ounce gold deposits and a significant iron ore resource, but remain under-researched. It is therefore important to constrain the fundamental geological setting. The igneous rocks of the eastern Kédougou-Kéniéba Inlier are dominantly of high-K calc-alkaline affinity, with fractionated REE patterns and negative Nb-Ta anomalies. The plutonic rocks in the Falémé Belt are dioritic to granodioritic in composition, with moderately fractionated REE patterns and metaluminous A/CNK signatures. Felsic, peraluminous granite stocks, dykes and plutons with fractionated REE patterns and negative Eu, Ti and P anomalies intruded both the Falémé Belt and Kofi Series. Albitisation masks the affinity of some units, although use of the Th-Co diagram shows that prior to albitisation, all igneous units belonged to the high-K calc-alkaline series. New U-Pb age data for the Boboti and Balangouma plutons indicate crystallisation at 2088.5 ± 8.5 Ma and at 2112 ± 13 Ma, respectively. Inherited zircons in the Boboti pluton indicate magmatic activity in the Falémé Belt at 2218 ± 83 Ma coincided with the oldest dated units in the Mako Belt to the West. Systematic changes in Dy/Yb, Sm/La, Nb/Zr, Rb concentration, Eu-anomaly and ɛNdt over ∼200 Ma reveal that the tectonic setting in the KKI evolved from a volcanic island arc environment to an active continental margin. Crustal thickening, as a result of a shift to collisional tectonic setting, combined with magmatic differentiation, led to the generation of peraluminous, granitic melts with a significant crustal component. A small suite of more basic intrusive and extrusive rocks on the eastern margin of the Dialé-Daléma basin are highly metaluminous and display limited LILE enrichment, with normalised HREE values close to unity. The Daléma igneous rocks may have formed in an extensional back arc, related to the arc system

Mercury flux to sediments of Lake Tahoe, California-Nevada

Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Water, Air, & Soil Pollution 210 (2010): 399-407, doi:10.1007/s11270-009-0262-y.We report estimates of mercury (Hg) flux to the sediments of Lake Tahoe, California-Nevada: 2 and 15-20 µg/m2/yr in preindustrial and modern sediments, respectively. These values result in a modern to preindustrial flux ratio of 7.5-10, which is similar to flux ratios recently reported for other alpine lakes in California, and greater than the value of 3 typically seen worldwide. We offer plausible hypotheses to explain the high flux ratios, including (1) proportionally less photoreduction and evasion of Hg with the onset of cultural eutrophication and (2) a combination of enhanced regional oxidation of gaseous elemental Hg and transport of the resulting reactive gaseous Hg to the surface with nightly downslope flows of air. If either of these mechanisms is correct, it could lead to local/regional solutions to lessen the impact of globally increasing anthropogenic emissions of Hg on Lake Tahoe and other alpine ecosystems.Funding was provided by Miami University, EPA-STAR, the Postdoctoral Scholar Program at Woods Hole Oceanographic Institution, and the USGS

Tracing the evolving flux from the subducting plate in the Tonga-Kermadec arc systemusing boron in volcanic glass

International audienceThe influence of fluid flux on petrogenesis in the Tonga-Kermadec Arc was investigated using ionmicroprobe measurements of B/Be and boron isotope ratios (11B/10B) to document the source and relativevolumes of the fluids released from the subducting oceanic plate. We analyzed young lavas from eightdifferent islands along the Tonga-Kermadec Arc, as well as glass shards in volcanic sediments from OceanDrilling Program (ODP) Site 840, which record the variations in the chemistry of Tonga magmatism since 7Ma. B/Be is variable (5.8 –122), in young Tonga-Kermadec Arc lavas. In contrast, glass shards from ;3 to4 Ma old volcanic sediments at Site 840 have the highest B/Be values yet reported for arc lavas (18–607).These values are too high to be related simply to a sediment influence on petrogenesis. Together with veryhigh d11B values (211.6 to 137.5) for the same shards and lavas these data indicate that most of the B isderived from fluid escaped from the subducting altered Pacific oceanic crust, rather than from sediment. Highd11B values also reflect large degrees of isotopic fractionation in this cold fast subduction zone. Lower d11Bvalues noted in the Kermadec Arc (17 to 24.4) are related to the influence of sediment eroded from NewZealand and slower convergence. High fluid flux (B/Be) is synchronous in Tonga and the Marianas at 3 to 4Ma and may be related to acceleration of the Pacific Plate just prior to this time.The timing of maximum B/Be at 3 to 4 Ma correlates with maximum light rare earth (LREE) and high fieldstrength element depletion. This suggests maximum degrees of partial melting at this time. Although thinningof the arc lithosphere during rifting to form the Lau Basin is expected to influence the arc geochemistry,variable aqueous fluid flux from the subducting plate alone appears capable of explaining boron and other traceelement systematics in the Tonga-Kermadec Arc with no indication of slab melting