5,552 research outputs found
Vanishing accounting journals due to paper deterioation: A laboratory study
Many accounting documents and journals disintegrate every year due to the acidic quality of paper used in them. Using the laboratory of the Office of Preservation of the Library of Congress, certain accounting journals were analyzed for their acidic or alkaline paper. Journals printed on acidic paper, such as the Accounting Historians Journal and the Accounting Review can be expected to disintegrate quickly. Journals printed on alkaline paper, such as the Journal of Accounting, Auditing & Finance and Taxation for Accountants should last for centuries. Historians wishing to preserve material appearing in acidic journals should photocopy on alkaline paper or use microfilm
Mutation of Arabidopsis SPLICEOSOMAL TIMEKEEPER LOCUS1 Causes Circadian Clock Defects
The circadian clock plays a crucial role in coordinating plant metabolic and physiological functions with predictable environmental variables, such as dusk and dawn, while also modulating responses to biotic and abiotic challenges. Much of the initial characterization of the circadian system has focused on transcriptional initiation, but it is now apparent that considerable regulation is exerted after this key regulatory step. Transcript processing, protein stability, and cofactor availability have all been reported to influence circadian rhythms in a variety of species. We used a genetic screen to identify a mutation within a putative RNA binding protein (SPLICEOSOMAL TIMEKEEPER LOCUS1 [STIPL1]) that induces a long circadian period phenotype under constant conditions. STIPL1 is a homolog of the spliceosomal proteins TFP11 (Homo sapiens) and Ntr1p (Saccharomyces cerevisiae) involved in spliceosome disassembly. Analysis of general and alternative splicing using a high-resolution RT-PCR system revealed that mutation of this protein causes less efficient splicing of most but not all of the introns analyzed. In particular, the altered accumulation of circadian-associated transcripts may contribute to the observed mutant phenotype. Interestingly, mutation of a close homolog of STIPL1, STIP-LIKE2, does not cause a circadian phenotype, which suggests divergence in function between these family members. Our work highlights the importance of posttranscriptional control within the clock mechanism. © 2012 American Society of Plant Biologists. All rights reserved
The Computer-Controlled Oculometer: A Prototype Interactive Eye Movement Tracking System
One kind of eye movement tracking device which has great potential is the digital computer-controlled Oculometer, an instrument which non-invasively measures point of regard of the subject, as well as pupil diameter and blink occurrence. In conjunction with a computer-generated display which can change in real time as a function of the subject's eye motions, the computer-controlled Oculometer makes possible a variety of interactive measurement and control systems. Practical applications of such schemes have had to await the development of an instrument design which does not inconvenience the subject, and which conveniently interfaces with a digital computer (see ref. 1). This report describes an Oculometer subsystem and an eye-tracking/control program designed for use with the PDP-6 computer of the MIT Project MAC Artificial Intelligence Group. The oculometer electro-optic subsystem utilizes near-infrared light reflected specularly off the front surface of the subject's cornea and diffusely off the retina, producing a bright pupil with an overriding corneal highlight. An electro-optic scanning aperture vidissector within the unit, driven by a digital eye-tracking algorithm programmed into the PDP-6 computer, detects and tracks the centers of the corneal highlight and the bright pupil to give eve movement measurements. A computer-controlled, moving mirror head motion tracker directly coupled to the vidissector tracker permits the subject reasonable freedom of movement. Various applications of this system, which are suggested by the work reported here, include; (a) using the eye as a control device, (b) recording eye fixation and exploring patterns, (c) game playing, (d) training machines, and (e) psychophysiological testing and recording
Part 2 of the 11+ as an effective home-based exercise programme in elite academy football (soccer) players:A one-club matched-paired randomised controlled trial
Background:Although the 11+ is known to reduce injuries and improve performance in adolescent footballers, its duration presents a notable barrier to implementation. Hence, this study investigated injury and performance outcomes when 65 elite male academy footballers either performed Part 2 3x/week at training (TG) or at home (HG). Methods:Time to stabilisation (TTS), eccentric hamstring strength (EH-S) and countermovement jump height (CMJ-H) were collected 4 times during the 2019 football season. Linear mixed models were used to evaluate main and interaction effects of group and time. Bonferroni post-hoc tests were used to account for multiple comparisons. Differences in time loss and medical attention injuries were determined using a two-tailed Z test for a comparison of rates. Results:Relative to baseline, EH-S (HG 4.3 kg, 95% CI 3 to 5.7, p \u3c 0.001; TG 5.5 kg, 95% CI 4.3 to 6.6, p \u3c 0.001) and CMJ-H (HG 3.5 cm, 95% CI 2.2 to 4.7, p \u3c 0.001; TG 3.2 cm, 95% CI 2.2 to 4.3, p \u3c 0.001) increased, with no difference between groups observed at the end of the season. All injury outcomes were similar. Conclusion: Rescheduling Part 2 did not affect performance or increased injury risks in academy footballers
Part 2 of the 11+ as an effective home-based exercise programme in elite academy football (soccer) players:a one-club matched-paired randomised controlled trial
Background: Although the 11+ is known to reduce injuries and improve performance in adolescent footballers, its duration presents a notable barrier to implementation. Hence, this study investigated injury and performance outcomes when 65 elite male academy footballers either performed Part 2 3x/week at training (TG) or at home (HG). Methods: Time to stabilisation (TTS), eccentric hamstring strength (EH-S) and countermovement jump height (CMJ-H) were collected 4 times during the 2019 football season. Linear mixed models were used to evaluate main and interaction effects of group and time. Bonferroni post-hoc tests were used to account for multiple comparisons. Differences in time loss and medical attention injuries were determined using a two-tailed Z test for a comparison of rates. Results: Relative to baseline, EH-S (HG 4.3 kg, 95% CI 3 to 5.7, p < 0.001; TG 5.5 kg, 95% CI 4.3 to 6.6, p < 0.001) and CMJ-H (HG 3.5 cm, 95% CI 2.2 to 4.7, p < 0.001; TG 3.2 cm, 95% CI 2.2 to 4.3, p < 0.001) increased, with no difference between groups observed at the end of the season. All injury outcomes were similar. Conclusion: Rescheduling Part 2 did not affect performance or increased injury risks in academy footballers.</p
Detection limits of organic compounds achievable with intense, short-pulse lasers
Many organic molecules have strong absorption bands which can be accessed by ultraviolet short pulse lasers to produce efficient ionization. This resonant multiphoton ionization scheme has already been exploited as an ionization source in time-of-flight mass spectrometers used for environmental trace analysis. In the present work we quantify the ultimate potential of this technique by measuring absolute ion yields produced from the interaction of 267 nm femtosecond laser pulses with the organic molecules indole and toluene, and gases Xe, N2 and O2. Using multiphoton ionization cross sections extracted from these results, we show that the laser pulse parameters required for real-time detection of aromatic molecules at concentrations of one part per trillion in air and a limit of detection of a few attomoles are achievable with presently available commercial laser systems. The potential applications for the analysis of human breath, blood and tissue samples are discussed
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Climate-driven regime shifts in a mangrove-salt marsh ecotone over the past 250 years.
Climate change is driving the tropicalization of temperate ecosystems by shifting the range edges of numerous species poleward. Over the past few decades, mangroves have rapidly displaced salt marshes near multiple poleward mangrove range limits, including in northeast Florida. It is uncertain whether such mangrove expansions are due to anthropogenic climate change or natural climate variability. We combined historical accounts from books, personal journals, scientific articles, logbooks, photographs, and maps with climate data to show that the current ecotone between mangroves and salt marshes in northeast Florida has shifted between mangrove and salt marsh dominance at least 6 times between the late 1700s and 2017 due to decadal-scale fluctuations in the frequency and intensity of extreme cold events. Model projections of daily minimum temperature from 2000 through 2100 indicate an increase in annual minimum temperature by 0.5 °C/decade. Thus, although recent mangrove range expansion should indeed be placed into a broader historical context of an oscillating system, climate projections suggest that the recent trend may represent a more permanent regime shift due to the effects of climate change
The GlueX DIRC Project
The GlueX experiment was designed to search for and study the pattern of
gluonic excitations in the meson spectrum produced through photoproduction
reactions at a new tagged photon beam facility in Hall D at Jefferson
Laboratory. The particle identification capabilities of the GlueX experiment
will be enhanced by constructing a DIRC (Detection of Internally Reflected
Cherenkov light) detector, utilizing components of the decommissioned BaBar
DIRC. The DIRC will allow systematic studies of kaon final states that are
essential for inferring the quark flavor content of both hybrid and
conventional mesons. The design for the GlueX DIRC is presented, including the
new expansion volumes that are currently under development.Comment: 8 pages, 6 figure
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