Showing papers by "David W. Johnson published in 1992"

Atmospheric deposition and forest nutrient cycling. A synthesis of the Integrated Forest Study.

Abstract: Over the past decade there has been considerable interest in the effects of atmospheric deposition on forest ecosystems This volume summarizes the results of the Integrated Forest Study (IFS), one of the most comprehensive research programs conducted It involved intensive measurements of deposition and nutrient cycling at seventeen diverse forested sites in the United States, Canada, and Norway The IFS is unique as an applied research project in its complete, ecosystem-level evaluation of nutrient budgets, including significant inputs, outputs, and internal fluxes It is also noteworthy as a more basic investigation of ecosystem nutrient cycling because of its incorporation of state-of-the-art methods, such as quantifying dry and cloud water deposition Most significantly, the IFS data was used to test several general hypotheses regarding atmospheric deposition and its effects The data sets also allow for far-reaching conclusions because all sites were monitored over the same period using comparable instruments and standardized protocols

Creative Controversy: Intellectual Challenge in the Classroom

Abstract: Imagine that you get such certain awesome experience and knowledge by only reading a book. How can? It seems to be greater when a book can be the best thing to discover. Books now will appear in printed and soft file collection. One of them is this book creative controversy intellectual challenge in the classroom. It is so usual with the printed books. However, many people sometimes have no space to bring the book for them; this is why they can't read the book wherever they want.

Simulations of deuterium-tritium experiments in TFTR

Abstract: A transport code (TRANSP) is used to simulate future deuterium-tritium (DT) experiments in TFTR. The simulations are derived from 14 TFTR DD discharges, and the modelling of one supershot is discussed in detail to indicate the degree of accuracy of the TRANSP modelling. Fusion energy yields and alpha particle parameters are calculated, including profiles of the alpha slowing down time, the alpha average energy, and the Alfven speed and frequency. Two types of simulation are discussed. The main emphasis is on the DT equivalent, where an equal mix of D and T is substituted for the D in the initial target plasma, and for the D0 in the neutral beam injection, but the other measured beam and plasma parameters are unchanged. This simulation does not assume that alpha heating will enhance the plasma parameters or that confinement will increase with the addition of tritium. The maximum relative fusion yield calculated for these simulations is QDT ~ 0.3, and the maximum alpha contribution to the central toroidal β is βα(0) ~ 0.5%. The stability of toroidicity induced Alfven eigenmodes (TAE) and kinetic ballooning modes (KBM) is discussed. The TAE mode is predicted to become unstable for some of the simulations, particularly after the termination of neutral beam injection. In the second type of simulation, empirical supershot scaling relations are used to project the performance at the maximum expected beam power. The MHD stability of the simulations is discussed

Effects of peer mediation training on elementary school students

Abstract: A peer mediation training program was conducted in three classrooms in a midwestern, suburban, middle-class elementary school. Prior to the training program, frequent conflicts involving teasing, playground activities, academic work, and so on, were reported. Students seemed conditioned to look to the teacher for a solution to their conflicts because they did not have the procedures and interpersonal skills necessary to manage conflicts constructively. The training program was successful in dramatically reducing the number of conflicts referred to the teacher, teaching mediation procedures and skills, and generalizing the procedures and skills to use in students' lives outside of the classroom and school.

The Use of Vaccines in Renal Failure

Abstract: Renal insufficiency is characterised by impaired host defences, which are compromised further by each of the 3 modes of renal replacement--haemodialysis, continuous ambulatory peritoneal dialysis (CAPD) and renal transplantation. Reduced renal clearance of unknown toxins, possible development of nutritional deficiencies and administration of immunosuppressive medications lead to aberrant immune regulation early in the course of renal failure. This results subsequently in increased frequency and severity of infection. Vaccination plays an important role in attenuating this infection risk, but impaired cell-mediated and humoral immunity contraindicates the use of live vaccines and engenders suboptimal and short-lived antibody responses to inactivated vaccines. Reinforced vaccination schedules, increased vaccine dosage and concomitantly administered adjuvant immunomodulators have variably improved the defective antibody responses to certain vaccines. Immunisation against hepatitis B virus has resulted in a significant decrease in prevalence and incidence of this infection in haemodialysis units. Similarly, the inoculation of influenza vaccine in patients with uraemia and of polyvalent pneumococcal vaccine in special risk circumstances has been recommended because of perceived reductions in morbidity and mortality from infection with these agents. Cytomegalovirus (CMV) vaccine may attenuate CMV disease severity in recipients of renal allografts. Staphylococcus aureus vaccine, on the other hand, is ineffective in preventing peritonitis or exit site infections in patients receiving CAPD. Other killed vaccines have not been comprehensively studied, but generally have the same indications for use as in normal individuals. However, the protection that these vaccines afford may be either inadequate or transient, so that other infection control strategies should be simultaneously implemented.

Controlling solid-state reaction mechanisms using diffusion length in ultrathin-film superlattice composites

Abstract: The synthetic parameters used by solid-state chemists have essentially been limited to temperature, pressure, composition, and time. Diffusion length can also be used as a synthetic parameter to alter the pathway of a solid-state reaction. Modulated, binary, ultrathin films of similar stoichiometry have been made whose repeat distance varies from 18 to 128 A. For samples whose modulation length is 38 A or larger, the films evolve upon heating as thin-film diffusion couples, initially growing an amorphous layer and then crystallizing a stable product, MoSe 2 , at the interface between individual elemental layers

Efficacy of adding nebulized ipratropium bromide to nebulized albuterol therapy in acute bronchiolitis.

Abstract: Nebulized ipratropium bromide is though to be synergistic with albuterol in therapy for acute childhood asthma. Because the efficacy of ipratropium in bronchiolitis is uncertain and some infants with bronchiolitis do not respond to nebulized albuterol alone, the following study was undertaken. In this double-blind, placebo-controlled trial, 69 infants between 6 weeks and 24 months of age who exhibited the first episode of acute bronchiolitis were randomly assigned to receive either nebulized albuterol (0.15 mg/kg per dose) and ipratropium bromide (250 micrograms per dose) (group A, n = 36) or nebulized albuterol and normal saline (placebo) (group B, n = 33) for two doses, 1 hour apart. The two groups were comparable at baseline. Both therapies resulted in clinically significant improvement. However, the addition of ipratropium resulted in no additional benefit with respect to decrease in the respiratory rate (mean decreases 10.6/min vs decreases 8.6/min, P = .86), accessory muscle score (range 0 through 3) (decreases 0.92 vs decreases 0.82, z = -0.44), wheeze score (range 0 through 3) (decreases 0.94 vs 0.85, z = -0.20), oxygen saturation (increases 0.25% vs increases -0.33%, P = .86), or hospitalization rate (17 vs 10). The number of "nonresponders" and "clear responders" was also very similar in both groups. No toxicity was noted. The increase in heart rate was mild and similar in both groups (increases 6.7 vs increases 11.1). The power of the study to detect a difference between the two treatment groups in the respiratory rate change > or = 8/min is greater than 90%.(ABSTRACT TRUNCATED AT 250 WORDS)

Computer docking system

Abstract: A computer docking system (10, 10') has a computer (11, 11') provided with a guide housing (12, 12') within which a device (13, 13') is slidably inserted. In one embodiment, the device (13) carries a pair of manually-releasable spring-loaded latches (24, 25) pivotally mounted thereon about respective axes which are substantially perpendicular to the direction which the device (13) is slidably inserted into the guide housing (12) for engagement with respective hooks (36) on the computer (11). In another embodiment, the latches (51, 52) are pivotably mounted on the guide housing (12') about respective axes which are substantially parallel to the direction in which the device (13') is slidably inserted into the guide housing (12'). The guide housing (12') includes a fixed bottom portion (44) on which the latches (51, 52) are pivotably mounted, and further includes a spring-loaded movable top portion (45) receiving the device (13') and ultimately nested telescopically within the fixed bottom portion (44). In each embodiment, a substantially zero insertion force ("ZIF") is achieved between at least one flexible electrical connector (41, 57, 58) and a circuit pad (43, 60, 61) as the device (13, 13') is inserted into the guide housing (12, 12').

The C/EBP family of transcriptional activators is functionally important for Ig VH promoter activity in vivo and in vitro.

Abstract: We have examined the functional importance of binding sites for C/EBP family members (E sites), in two Ig VH promoters: VH1, a member of the S107 family, and BCL1, a member of the J558 family. Mutation of the E site in the VH1 promoter diminishes transcription in vivo to 59% of wild-type and transcription from the BCL1 promoter in vitro is inhibited to an average of 39% of wild-type by competition with E site oligonucleotides. Purified E site binding proteins from plasmacytoma cells stimulated BCL1 transcription in vitro 2.3-fold. Although five C/EBP family proteins are known which bind the E site, antibody ablation of DNA:protein complexes resolved by electrophoretic mobility shift assays showed that Ig/EBP-1 is the only E site binding protein detectable in early B cell lines; more mature B cells contain Ig/EBP-1 and NF-IL6. We also show by antibody-depletion that Ig/EBP-1 activates the BCL1 promoter in vitro.

Frequency of Salmonella enteritidis and other salmonellae in the ceca of spent hens at time of slaughter.

Abstract: A study was conducted to determine the frequency of Salmonella enteritidis (SE) and other Salmonella serovars in the cecal contents of spent laying hens at a hen-processing plant in the southeastern United States over a 4 1/2-month period, from October 1990 through February 1991. A total of 1920 pooled cecal samples (three ceca per sample) from 38 flocks representing 23 producers were obtained and tested for the presence of SE and other Salmonella serovars. A total of 359 samples (18.7%) from 37 of the 38 flocks (97.4%) showed characteristic reactions for salmonellae on triple sugar iron agar (TSIA) slants. Twenty-nine of the 359 Salmonella-positive samples (8.1%) were Group D-positive, all of which were found to be SE on further serotyping. The SE-positive samples were from seven of the 38 flocks (18.4%); four flocks originated from the USDA/APHIS-designated Northern Region of the United States, and three were from the Southeastern Region. Serotyping of the 330 TSIA-positive Group-D negative Salmonella revealed 37 different serovars. S. heidelberg, the predominant serovar, was identified in 49.1% of these isolates.

Very long-chain fatty acids in peroxisomal disease.

Abstract: Fatty acids with from 24 to 28 carbon atoms (very long-chain fatty acids, VLCFA) are present in small amounts in all mammalian tissues. Even longer chain fatty acids with from 30 to 38 carbon atoms (ultra-long-chain fatty acids, ULCFA) are found in certain specialized tissues including retina, brain, and spermatozoa. In patients with inherited defects in peroxisomal structure and/or function, there is an accumulation of VLCFA in most tissues, while VLCFA and ULCFA levels are increased in brain. The most pronounced changes occur in those patients who have defects in peroxisomal assembly (Zellweger syndrome, infantile Refsumts disease, and neonatal adrenoleukodystrophy). In the brain of these individuals, ULCFA are distributed largely in molecular species of phosphatidylcholine with penta-, hexa-, and heptaenoic acids. In contrast, patients with X-linked adrenoleukodystrophy have increased levels of phosphatidylcholine with monoenoic rather than polyenoic ULCFA. A defect in a peroxisomal VLCFA CoA synthetase or ligase has been reported for these patients, but assembly of their peroxisomes is apparently normal.

Monoenoic fatty acids in human brain lipids: isomer identification and distribution.

Abstract: The carbon chain length distribution and the double bond positional isomer composition of the monoenoic fatty acids of the lipids of total human brain tissue have been determined using gas chromatography and gas chromatography/mass spectrometry of the fatty acid methyl and picolinyl esters. The even chain length monoenoic C16 to C28 fatty acids contain predominantly two positional isomer series, the n−7 and n−9cis homologues, whose relative proportion varies significantly with chain length. The odd chain length long-chain fatty acids consist of n−8 and n−10 isomers, whereas the odd chain length very long-chain (more than 22 carbon) fatty acids are n−7 and n−9 isomers.

SMA burn-in socket

Abstract: A burn-in socket for integrated circuit chips has a clamping means actuated by a thermally-reactive resilient means, operative during the burn-in cycle itself, such that the chip frames are retained and good electrical contact with the chip leads is maintained during burn-in.

Mechanical and electrical clamping mechanisms between a "mother" board and a "daughter" board in an electronic assembly

Abstract: A connector body (10 10', 10") is mounted on a mother board (11) and has a compressible electrical connector (15). A daughter board (22) is slidably inserted into the connector body (10, 10', 10") perpendicularly of the mother board (11). A deflection means (34, 56) engages a side of the daughter board (22) and deflects the daughter board (22) away from the compressible electrical connector (15) to prevent damage thereto after the daughter board (22) is slidably inserted. When the daughter board (22) is fully inserted, a retaining means 28, 43, 69) exerts a lateral clamping force on the daughter board (22).

Alignment of TFTR Thomson scattering system

Abstract: A technique is described for maintaining the highly precise alignment needed for accurate density profile measurements with the TFTR Thomson scattering system. The method uses the transverse coherence of the fiber bundles in the collection optics to encode the alignment information in the spatial distribution of the scattered light signal. A scheme for decoding this information is demonstrated and the limitations of this technique are discussed.

Error analysis for charge exchange recombination spectrometer measurements of ion temperature

Abstract: A two‐dimensional intensified photodiode array is used to measure charge exchange recombination emission in the TFTR. The noise of this detector has been characterized to provide a better estimation of the error bars associated with ion temperature measurements. Contributions to the measured signal include a dc level offset, an integrated dark signal, and the actual photon signal. In addition to photon noise, there is a significant readout noise. The analysis was complicated by a nonlinear response of the readout circuitry. The detector output is linearized and the pixel‐to‐pixel gain variation is removed with a white field correction. The noise has been modeled over a range of integration times of the detector and gains of the intensifier, allowing an estimation of the uncertainty in the measurement at each pixel, and therefore its appropriate weight in the fitting function.

Compressible electrical connectors for large board spacings

Abstract: A compressible electrical connector (10) includes a rigid molded body (11) having elastomeric caps (19, 20) at the top (12) and bottom (13) thereof. A thin flexible film (21), provided with respective connector elements (22), is wrapped around the rigid molded body (11) and its caps (19, 20) and is retained by a film retaining plate (23). The film retaining plate (23) has a plurality of latching lances (24) received in corresponding mounting holes (30) formed transversely in the rigid molded body (11). A hot melt layer (36) is placed over the film retaining plate (23), and a plurality of compressible electrical connectors (10) are stacked side-by-side to form an array (35). The array (35) is disposed between a pair of PC boards or other electronic assemblies (39, 40) having respective circuit elements (37, 38). The height of the rigid molded body may be changed conveniently to readily accommodate different product applications.

Interface system for angularly-converging printed circuit boards

Abstract: A pair of printed circuit boards (11, 12) angularly converge towards each other about a pivot axis (13). Each of the boards (11, 12) carries a connector housing (16). The connector housings (16) are identical, but are inverted end-to-end with respect to each other, such that a plurality of hermaphroditic guide fingers (19) on one of the connector housings (16) will mesh with a complementary plurality of guide fingers (19) on the other connector housing (16). The meshing engagement of the guide fingers (19) provides a guide means and a stop means between the connector housings (16) and hence between the printed circuit boards (11, 12). Each of the identical connector housings (16) further has a flexible electrical connector (17), and the flexible electrical connectors (17) engage each other when the printed circuit boards (11, 12) are fully converged. Inclined surfaces (21, 22) on the meshing guide fingers (19) provide a self-alignment feature as the printed circuit boards (11, 12) and the connector housings (16) thereon are angularly converged. Preferably, each connector housing (16) has spaced-apart pairs of bifurcated latching fingers (23) such that the connector housing (16) is "snapped" on to its respective printed circuit board (11, 12).