12,397 research outputs found
Computer program documentation user information for the MPAD trajectory tape print program (TRJPR1)
The Trajectory Tape Print Program (TRJPR1) was developed to print applicable information from a Space Trajectory tape created by the Mission Planning and Analysis Division (MPAD) in the MPAD Common Format for the on-orbit phase of the Mission. Instructions for TRJPR1's use are given
Computer program documentation user information for the RSO-tape print program (RSOPRNT)
A user's guide for the RSOPRNT, a TRASYS Master Restart Output Tape (RSO) reader is presented. Background information and sample runstreams, as well as, references, input requirements and options, are included
Pion Charge Exchange on Deuterium
We investigate quantum corrections to a classical intranuclear cascade
simulation of pion single charge exchange on the deuteron. In order to separate
various effects the orders of scattering need to be distinguished and, to that
end, we develop signals for each order of scattering corresponding to
quasi-free conditions. Quantum corrections are evaluated for double scattering
and are found to be large. Global agreement with the data is good.Comment: 30 pages, 12 figure
Low-dose alum application trialled as a management tool for internal nutrient loads in Lake Okaro, New Zealand
Aluminium sulfate (alum) was applied to Lake Okaro, a eutrophic New Zealand lake with recurrent cyanobacterial blooms, to evaluate its suitability for reducing trophic status and bloom frequency. The dose yielded 0.6 g aluminium m–3 in the epilimnion. Before dosing, pH exceeded 8 in epilimnetic waters but was optimal for flocculation (6–8) below 4 m depth. After dosing, there was no significant change in water clarity, hypolimnetic pH decreased to 5.5, and soluble aluminium exceeded recommended guidelines for protection of freshwater organisms. Epilimnetic phosphate concentrations decreased from 40 to 5 mg m–3 and total nitrogen (TN):total phosphorus (TP) mass ratios increased from 7:1 to 37:1. The dominant phytoplankton species changed from Anabaena spp. before dosing, to Ceratium hirudinella , then Staurastrum sp. after dosing. Detection of effectiveness of dosing may have been limited by sampling duration and design, as well as the low alum dose. The decrease in hypolimnetic pH and epilimnetic TP, and increase in Al3+ and chlorophyll a, are attributed to the low alkalinity lake water and coincidence of alum dosing with a cyanobacterial bloom and high pH
The photon blockade effect in optomechanical systems
We analyze the photon statistics of a weakly driven optomechanical system and
discuss the effect of photon blockade under single photon strong coupling
conditions. We present an intuitive interpretation of this effect in terms of
displaced oscillator states and derive analytic expressions for the cavity
excitation spectrum and the two photon correlation function . Our
results predict the appearance of non-classical photon correlations in the
combined strong coupling and sideband resolved regime, and provide a first
detailed understanding of photon-photon interactions in strong coupling
optomechanics
Symbiont 'bleaching' in planktic foraminifera during the Middle Eocene Climatic Optimum
Many genera of modern planktic foraminifera are adapted to nutrient-poor (oligotrophic) surface waters by hosting photosynthetic symbionts, but it is unknown how they will respond to future changes in ocean temperature and acidity. Here we show that ca. 40 Ma, some fossil photosymbiont-bearing planktic foraminifera were temporarily 'bleached' of their symbionts coincident with transient global warming during the Middle Eocene Climatic Optimum (MECO). At Ocean Drilling Program (ODP) Sites 748 and 1051 (Southern Ocean and mid-latitude North Atlantic, respectively), the typically positive relationship between the size of photosymbiont-bearing planktic foraminifer tests and their carbon isotope ratios (δ13C) was temporarily reduced for ∼100 k.y. during the peak of the MECO. At the same time, the typically photosymbiont-bearing planktic foraminifera Acarinina suffered transient reductions in test size and relative abundance, indicating ecological stress. The coincidence of minimum δ18O values and reduction in test size–δ13C gradients suggests a link between increased sea-surface temperatures and bleaching during the MECO, although changes in pH and nutrient availability may also have played a role. Our findings show that host-photosymbiont interactions are not constant through geological time, with implications for both the evolution of trophic strategies in marine plankton and the reliability of geochemical proxy records generated from symbiont-bearing planktic foraminifera
New biostratigraphic, magnetostratigraphic and isotopic insights into the Middle Eocene Climatic Optimum in low latitudes
The Middle Eocene Climatic Optimum (MECO) was a warming event that interrupted the long-term Eocene cooling trend. While this event is well documented at high southern and mid-latitudes, it is poorly known from low latitudes and its timing and duration are not well constrained because of problems of hiati, microfossil preservation and weak magnetic polarity in key sedimentary sections. Here, we report the results of a study designed to improve the bio-, magneto- and chemostratigraphy of the MECO interval using high-resolution records from two low-latitude sections in the Atlantic Ocean, Ocean Drilling Program (ODP) Sites 1051 and 1260. We present the first detailed benthic foraminiferal stable isotope records of the MECO from the low latitudes as well as the biostratigraphic counts of Orbulinoides beckmanni and new magnetostratigraphic results. Our data demonstrate a ~ 750 kyr-long duration for the MECO characterized by increasing δ13C and decreasing δ18O, with minimum δ18O values lasting ~ 40 kyr at 40.1 Ma coincident with a short-lived negative δ13C excursion. Thereafter, δ18O and δ13C values recover rapidly. The shift to minimum δ18O values at 40.1 Ma is coincident with a marked increase in the abundance of the planktonic foraminifera O. beckmanni, consistent with its inferred warm-water preference. O. beckmanni is an important Eocene biostratigraphic marker, defining planktonic foraminiferal Zone E12 with its lowest and highest occurrences (LO and HOs). Our new records reveal that the LO of O. beckmanni is distinctly diachronous, appearing ~ 500 kyr earlier in the equatorial Atlantic than in the subtropics (40.5 versus 41.0 Ma). We also show that, at both sites, the HO of O. beckmanni at 39.5 Ma is younger than the published calibrations, increasing the duration of Zone E12 by at least 400 kyr. In accordance with the tropical origins of O. beckmanni, this range expansion to higher latitudes may have occurred in response to sea surface warming during the MECO and subsequently disappeared with cooling of surface waters
The Contribution of the Light Quark Condensate to the Pion-Nucleon Sigma Term
There has been a discrepancy between values of the pion-nucleon sigma term
extracted by two different methods for many years. Analysis of recent high
precision pion-nucleon data has widened the gap between the two determinations.
It is argued that the two extractions correspond to different quantities and
that the difference between them can be understood and calculated.Comment: Modern Physics Letters A (in press
Discipline-Specific Compared to Generic Training of Teachers in Higher Education
A recurrent theme arising in the higher education sector is the suitability and effectiveness of generic versus discipline-specific training of university teachers, who are often recruited based on their disciplinary specialties to become teachers in higher education. We compared two groups of participants who had undergone training using a generic post-graduate certificate in higher education (PGCertGeneric) versus a discipline-specific course in veterinary education (PGCertVetEd). The study was conducted using a survey that allowed comparison of participants who completed PGCertGeneric (n=21) with PGCertVetEd (n=22). Results indicated that participants from both PGCertGeneric and PGCertVetEd considered teaching to be satisfying and important to their careers, valued the teaching observation component of the course, and identified similar training needs. However, the participants of the PGCertVetEd felt that the course made them better teachers, valued the relevance of the components taught, understood course design better, were encouraged to do further courses/reading in teaching and learning, changed their teaching as a result of the course, and were less stressed about teaching as compared to the PGCertGeneric participants (p<.05). It is likely that the PGCertVetEd, which was designed and developed by veterinarians with a wider understanding of the veterinary sector, helped the participants perceive the training course as suited to their needs
An Hedonic Analysis of the Effects of Lake Water Clarity on New Hampshire Lakefront Properties
Policy makers often face the problem of evaluating how water quality affects a region's economic well-being. Using water clarity as a measure of the degree of eutrophication levels (as a lake becomes inundated with nutrients, water clarity decreases markedly), analysis is performed on sales data collected over a six-year period. Our results indicate that water clarity has a significant effect on prices paid for residential properties. Effects of a one-meter change in clarity on property value are also estimated for an average lake in four real estate market areas in New Hampshire, with effects differing substantially by area. Our findings provide state and local policy makers a measure of the cost of water quality degradation as measured by changes in water clarity, and demonstrate that protecting water quality may have a positive effect on property tax revenues.Resource /Energy Economics and Policy,
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