Gross domestic product and its components in recessions

The recent economic crisis – already deservedly labeled the ‘great recession’ – continues to plague the health of the economy as a whole and has motivated us to probe its characteristic features and compare it to the typical economic downturn. Events during the boom and crash have been sharply delineated, progressing from (1) an unprecedented housing price bubble from 1997 to 2006, (2) rapid house price decline beginning early in 2007, (3) freezing of credit markets in August 2007, (4) rapid declines in equities prices and economic output by the middle of 2008, and (5) deterioration of the financial system in 2008 and an aggressive and unprecedented Federal Reserve intervention in the fall of 2008. This sequence of events has provided a fresh perspective with which to examine past economic cycles, and, we believe, is likely to change how economists, policy makers, investors, and others think about monetary policy, housing cycles, and business cycles. We find that eleven of the most recent fourteen economic downturns in the U.S. – from the great depression that began in 1929 to the great recession starting in late 2007 – were led by declines in housing investment. In these eleven downturns, housing investment declined before any other major component of GDP and its total decline before and during the recession was larger in percentage terms than the decline in any other major sector. In the 1945 recession – one of the three recessions in which housing was not implicated – national defense expenditures fell while all major components of private expenditure rose. The other two – in 1937-38 and 2001 – resulted primarily from declines in non-residential fixed investment that preceded and exceeded declines in any other major component of GDP. Figure 1 shows the percentage of GDP contributed by housing expenditures over the past 81 years. Although housing is not a large component of GDP – which may explain its limited role in accounts of recessions – it is volatile, it has declined before almost every recession, it has rarely declined substantially without a recession following soon afterward, and the extent of its decline emerges as a good predictor of the depth and duration of the recession that follows.2 In addition to its role as a leading indicator, and its volatility over the business cycle, housing investment has recovered faster than any other sector of the economy in every recession since 1921, with the single exception of the 1980 recession, which lasted only 12 months.

Balance Sheet Crises: Causes, Consequences and Responses

We propose that the severity of the Depression beginning in 1929, and that of the Great Recession starting in 2007 were twin household-bank balance sheet crises—events that were quite distinguishable from the recessions appearing between them. Each episode, we hypothesize, was preceded by unsustainable rises in expenditures on construction of new housing units and in mortgage credit for purchases of new and existing homes. In both cases housing values rapidly collapsed by over thirty percent but mortgage debt obligations fell only very slowly, so that housing equity fell sharply

P/N InP solar cells on Ge wafers

Indium phosphide (InP) P-on-N one-sun solar cells were epitaxially grown using a metalorganic chemical vapor deposition process on germanium (Ge) wafers. The motivation for this work is to replace expensive InP wafers, which are fragile and must be thick and therefore heavy, with less expensive Ge wafers, which are stronger, allowing use of thinner, lighter weight wafers. An intermediate InxGs1-xP grading layer starting as In(0.49)Ga(0.51) at the GaAs-coated Ge wafer surface and ending as InP at the top of the grading layer (backside of the InP cell) was used to attempt to bend some of the threading dislocations generated by lattice-mismatch between the Ge wafer and InP cell so they would be harmlessly confined in this grading layer. The best InP/Ge cell was independently measured by NASA-Lewis with a one-sun 25 C AMO efficiently measured by NASA-Lewis with a one-circuit photocurrent 22.6 mA/sq cm. We believe this is the first published report of an InP cell grown on a Ge wafer. Why get excited over a 9 percent InP/Ge cell? If we look at the cell weight and efficiency, a 9 percent InP cell on an 8 mil Ge wafer has about the same cell power density, 118 W/kg (BOL), as the best InP cell ever made, a 19 percent InP cell on an 18 mil InP wafer, because of the lighter Ge wafer weight. As cell panel materials become lighter, the cell weight becomes more important, and the advantage of lightweight cells to the panel power density becomes more important. In addition, although InP/Ge cells have a low beginning-of-life (BOL) efficiency due to dislocation defects, the InP/Ge cells are very radiation hard (end-of-life power similar to beginning-of-life). We have irradiated an InP/Ge cell with alpha particles to an equivalent fluence of 1.6 x 10(exp 16) 1 MeV electrons/sq cm and the efficiency is still 83 percent of its BOL value. At this fluence level, the power output of these InP/Ge cells matches the GaAs/Ge cell data tabulated in the JPL handbook. Data are presented indicating InP/Ge has more power output than GaAs/Ge cells at fluences in excess of this value

The effectiveness of a technologically facilitated classroom-based early reading intervention: The targeted Reading Intervention

The purpose of this study was to evaluate the efficacy of a classroom-teacher-delivered reading intervention for struggling readers called the Targeted Reading Intervention (TRI), designed particularly for kindergarten and first-grade teachers and their struggling students in rural, low-wealth communities. The TRI was delivered via an innovative Web-conferencing system using laptop computers and webcam technology. Seven schools from the southwestern United States were randomly assigned to experimental and control conditions in a cluster randomized design. All children in the study (n = 364) were administered a battery of standardized reading skill tests in the fall and spring of the school year. Intent-to-treat analyses were conducted to estimate mixed models of children’s 1-year growth in Word Attack, Letter/Word Identification, Passage Comprehension, and Spelling of Sounds. Results showed that struggling readers from experimental schools outperformed those from control schools on all spring reading outcomes, controlling for fall scores

Modelling of deposition processes on the TiO2 rutile (110) surface

Deposition of TixOy clusters onto the rutile TiO2 (1 1 0) surface has been modelled using empirical potential based molecular dynamics. Deposition energies in the range 10–40 eV have been considered so as to model typical deposition energies of magnetron sputtering. Defects formed as a function of both the deposition energy and deposition species have been studied. The results show that in the majority of cases Ti interstitial atoms are formed, irrespective of whether Ti was contained within the deposited cluster. Furthermore that the majority of these interstitials are formed by displacing a surface Ti atom into the interstitial site. O surface atoms are also relatively common, with Ti and TiO2 surface units often occurring when the deposited cluster contains Ti but becoming less frequent as the deposition energy is increased. Structures that would give rise to the growth of further layers of rutile are not observed and in the majority of the simulations the energy barriers for diffusion of the end-products is high

Time Series Measurements of Chlorophyll Fluorescence in the Oceanic Bottom Boundary Layer With a Multisensor Fiber-Optic Fluorometer

An in situ multisensor fiber-optic fluorometer (MFF) has been developed to acquire long-term chlorophyll fluorescence measurements in the oceanic bottom boundary layer to characterize the finescale pigment structure at vertical spatial scales comparable to physical measurements. The eight fluorescence sensors of the MFF are composed of dual optical fibers of varying lengths (1.5-8 m), with the fiber ends oriented at 30 degrees to each other and enclosed by a small light baffle. Strobe excitation blue light is passed through one of each pair of optical fibers and stimulated chlorophyll fluorescence is carried back to a photomultiplier. Two sets of four fluorescence sensors assigned to high- and low-sensitivity photomultiplier detectors enable chlorophyll a measurements in two ranges, 0-50 mg m(-3) and 0-200 mg m(-3), respectively. Aspects of the design of the fiber-optic sensor are described that were intended to optimize detection of fluorescence signals and minimize interference by ambient light. The fiber-optic sensor outputs were stable with minimal instrument drift during long-term field operations, and measurements were not affected by turbidity and ambient light. A vertical array of fiber-optic fluorescence sensors supported on a tripod has been deployed at coastal sites for up to seven weeks and chlorophyll fluorescence was obtained with sufficiently high vertical spatial and temporal resolution

The Government Contracts Reference Book: A Comprehensive Guide to the Language of Procurement

This book - first published in 1992 and now in its fifth edition - is intended to offer concise, comprehensive information to the practitioner of the art of government contracting. Looking up a key term, the reader can find a definition, followed by a summary of where the term is used in the statutes or regulations dealing with the procurement process. The book also includes references to literature where the term is more fully discussed. The book is not designed as a standalone encyclopedia: it is a first reference, pointing the user to additional sources as needed. The book makes it clear that government contracting is complex, and the rules cannot be gleaned from a single source such as the Federal Acquisition Regulation. They can only be learned from constant reading of reference materials and textbooks—not to mention decisions of the courts, boards of contract appeals, and the Government Accountability Office. Navigating the waters of government procurement is an arduous task, and this book is intended as an aid in that journey. The authors fully understand that it is impossible to make the book fully comprehensive. While this edition is (again) expanded, we know additional terms could be added. We welcome readers to let us know of terms that should be included in the next edition

Scales of Seafloor Sediment Resuspension in the Northern Gulf of Mexico

Seafloor sediment resuspension events of different scales and magnitudes and the resulting deep (\u3e1,000 m) benthic nepheloid layers were investigated in the northern Gulf of Mexico during Fall 2012 to Summer 2013. Time-series data of size-specific in-situ settling speeds of marine snow in the benthic nepheloid layer (moored flux cameras), particle size distributions (profiling camera), currents (various current meters) and stacked time-series flux data (sediment traps) were combined to recognize resuspension events ranging from small-scale local, to small-scale far-field to hurricane-scale. One smallscale local resuspension event caused by inertial currents was identified based on local high current speeds (\u3e10 cm s–1) and trap data. Low POC content combined with high lithogenic silica flux at 30 m above bottom (mab) compared to the flux at 120 mab, suggested local resuspension reaching 30 mab, but not 120 mab. Another similar event was detected by the changes in particle size distribution and settling speeds of particles in the benthic nepheloid layer. Flux data indicated two other small-scale events, which occurred at some distance, rather than locally. Inertia-driven resuspension of material in shallower areas surrounding the traps presumably transported this material downslope leaving a resuspension signal at 120 mab, but not at 30 mab. The passage of hurricane Isaac left a larger scale resuspension event that lasted a few days and was recorded in both traps. Although hurricanes cause large-scale events readily observable in sediment trap samples, resuspension events small in temporal and spatial scale are not easily recognizable in trapped material as they tend to provide less material and become part of the background signal in the long-term averaged trap samples. We suggest that these small-scale resuspension events, mostly unnoticed in conventional time-series sampling, play an important role in the redistribution and ultimate fate of sediment distribution on the seafloor

Bioactivity of common pesticidal plants on fall armyworm larvae (spodoptera frugiperda)

The fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae) is a recent invasive pest species that has successfully established across sub‐Saharan Africa where it continues to disrupt agriculture, particularly smallholder cereal production. Management of FAW in its native range in the Americas has led to the development of resistance to many commercial pesticides before its arrival in Africa. Pesticide use may therefore be ineffective for FAW control in Africa, so new and more sustainable approaches to pest management are required that can help reduce the impact of this exotic pest. Pesticidal plants provide an effective and established approach to pest management in African smallholder farming and recent research has shown that their use can be cost‐beneficial and sustainable. In order to optimize the use of botanical extracts for FAW control, we initially screened ten commonly used plant species. In laboratory trials, contact toxicity and feeding bioassays showed differential effects. Some plant species had little to no effect when compared to untreated controls; thus, only the five most promising plant species were selected for more detailed study. In contact toxicity tests, the highest larval mortality was obtained from Nicotiana tabacum (66%) and Lippia javanica (66%). Similarly, in a feeding bioassay L. javanica (62%) and N. tabacum (60%) exhibited high larval mortality at the highest concentration evaluated (10% w/v). Feeding deterrence was evaluated using glass‐fibre discs treated with plant extracts, which showed that Cymbopogon citratus (36%) and Azadirachta indica (20%) were the most potent feeding deterrents among the pesticidal plants evaluated. In a screenhouse experiment where living maize plants infested with fall armyworm larvae were treated with plant extracts, N. tabacum and L. javanica were the most potent species at reducing foliar damage compared to the untreated control whilst the synthetic pesticide chlorpyrifos was the most effective in reducing fall armyworm foliar damage. Further field trial evaluation is recommended, particularly involving smallholder maize fields to assess effectiveness across a range of contexts