49 research outputs found
Kuiper Belt Occultation Predictions
Here we present observations of seven large Kuiper Belt objects. From these observations, we extract a point source catalog with ∼0.01″ precision, and astrometry of our target Kuiper Belt objects with 0.04–0.08″ precision within that catalog. We have developed a new technique to predict the future occurrence of stellar occultations by Kuiper Belt objects. The technique makes use of a maximum likelihood approach which determines the best-fit adjustment to cataloged orbital elements of an object. Using simulations of a theoretical object, we discuss the merits and weaknesses of this technique compared to the commonly adopted ephemeris offset approach. We demonstrate that both methods suffer from separate weaknesses, and thus together provide a fair assessment of the true uncertainty in a particular prediction. We present occultation predictions made by both methods for the seven tracked objects, with dates as late as 2015. Finally, we discuss observations of three separate close passages of Quaoar to field stars, which reveal the accuracy of the element adjustment approach, and which also demonstrate the necessity of considering the uncertainty in stellar position when assessing potential occultations
Prospectus, May 7, 1981
SPEECH TEAM 11TH RANKED; National Forensics Top 20; C of C V-P, Neils predicts downtown area will change; Overcast and Snyder receive award; Co-Editors named for 1981-82; Barnes looks back on his Parkland experiences; Letters to the Editor: Student criticizes review; Classifieds; Our mistake! Stugo candidate got platform in on time; Convocations Wants You!!; Now is the time to get married; More letters to the Editor: New Stugo senator, Jackson appreciates support; Schumacher\u27s final notes...; Trail, Hillary win in close Stugo election last week; Trail expresses gratitude for the voters; Be kind to animals ; Japan King of bicycle road; Motocross bikes good for kids; Rogers, Gayle at Assembly Hall May 13.; Off Broadway: Dynamic, Aggressive; Gayle not living under Lorett\u27s shadow now!; Piloting not as easy as you may think!; Drug problem is going to get worse. ; Art Thesis Exhibit disappointing; Latin may be on its way back; Parkland secretaries enjoy the good life; Model Rockets popular; RWS\u27S help each other; PC offers one-day driving course; Ramblin\u27: Alender\u27s rambles are over; Rundgren just changing with the times; Do you want hard rock...?; Frazier, Turpin part of Senior May Fest; Here\u27s the 1981 Prospectus staff; CIRS has the info on day care; Did You Know That...Some Superstitions; \u27Recent rains still not enough\u27: Burwash; Barkstall appalled by Atlanta slayings: Urban League director says blacks are still discriminated against; Are we running out of natural resources?; Get out your horses for PC\u27s Horse Show; Parkland Happenings: Spring concerts feature Irving Berlin; Awards Banquet a success!; Winning Intellectual Freedom Essay; A child\u27s world is important throughout all stages; Dental classes named for \u2781-82; Final Examinations -- Spring, 1981; Cobras bow to Lake Land; Patrick to Tennessee; Softball team beats Danville; ...beat Lincoln Land three; Letter to the Sports Editor: Student upset; Walder wins final Fast Freddy; scoreboard; Baseballhttps://spark.parkland.edu/prospectus_1981/1017/thumbnail.jp
Heliophysics and Amateur Radio:Citizen Science Collaborations for Atmospheric, Ionospheric, and Space Physics Research and Operations
The amateur radio community is a global, highly engaged, and technical community with an intense interest in space weather, its underlying physics, and how it impacts radio communications. The large-scale observational capabilities of distributed instrumentation fielded by amateur radio operators and radio science enthusiasts offers a tremendous opportunity to advance the fields of heliophysics, radio science, and space weather. Well-established amateur radio networks like the RBN, WSPRNet, and PSKReporter already provide rich, ever-growing, long-term data of bottomside ionospheric observations. Up-and-coming purpose-built citizen science networks, and their associated novel instruments, offer opportunities for citizen scientists, professional researchers, and industry to field networks for specific science questions and operational needs. Here, we discuss the scientific and technical capabilities of the global amateur radio community, review methods of collaboration between the amateur radio and professional scientific community, and review recent peer-reviewed studies that have made use of amateur radio data and methods. Finally, we present recommendations submitted to the U.S. National Academy of Science Decadal Survey for Solar and Space Physics (Heliophysics) 2024–2033 for using amateur radio to further advance heliophysics and for fostering deeper collaborations between the professional science and amateur radio communities. Technical recommendations include increasing support for distributed instrumentation fielded by amateur radio operators and citizen scientists, developing novel transmissions of RF signals that can be used in citizen science experiments, developing new amateur radio modes that simultaneously allow for communications and ionospheric sounding, and formally incorporating the amateur radio community and its observational assets into the Space Weather R2O2R framework. Collaborative recommendations include allocating resources for amateur radio citizen science research projects and activities, developing amateur radio research and educational activities in collaboration with leading organizations within the amateur radio community, facilitating communication and collegiality between professional researchers and amateurs, ensuring that proposed projects are of a mutual benefit to both the professional research and amateur radio communities, and working towards diverse, equitable, and inclusive communities
Antiinflammatory Therapy with Canakinumab for Atherosclerotic Disease
Background: Experimental and clinical data suggest that reducing inflammation without affecting lipid levels may reduce the risk of cardiovascular disease. Yet, the inflammatory hypothesis of atherothrombosis has remained unproved. Methods: We conducted a randomized, double-blind trial of canakinumab, a therapeutic monoclonal antibody targeting interleukin-1β, involving 10,061 patients with previous myocardial infarction and a high-sensitivity C-reactive protein level of 2 mg or more per liter. The trial compared three doses of canakinumab (50 mg, 150 mg, and 300 mg, administered subcutaneously every 3 months) with placebo. The primary efficacy end point was nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death. RESULTS: At 48 months, the median reduction from baseline in the high-sensitivity C-reactive protein level was 26 percentage points greater in the group that received the 50-mg dose of canakinumab, 37 percentage points greater in the 150-mg group, and 41 percentage points greater in the 300-mg group than in the placebo group. Canakinumab did not reduce lipid levels from baseline. At a median follow-up of 3.7 years, the incidence rate for the primary end point was 4.50 events per 100 person-years in the placebo group, 4.11 events per 100 person-years in the 50-mg group, 3.86 events per 100 person-years in the 150-mg group, and 3.90 events per 100 person-years in the 300-mg group. The hazard ratios as compared with placebo were as follows: in the 50-mg group, 0.93 (95% confidence interval [CI], 0.80 to 1.07; P = 0.30); in the 150-mg group, 0.85 (95% CI, 0.74 to 0.98; P = 0.021); and in the 300-mg group, 0.86 (95% CI, 0.75 to 0.99; P = 0.031). The 150-mg dose, but not the other doses, met the prespecified multiplicity-adjusted threshold for statistical significance for the primary end point and the secondary end point that additionally included hospitalization for unstable angina that led to urgent revascularization (hazard ratio vs. placebo, 0.83; 95% CI, 0.73 to 0.95; P = 0.005). Canakinumab was associated with a higher incidence of fatal infection than was placebo. There was no significant difference in all-cause mortality (hazard ratio for all canakinumab doses vs. placebo, 0.94; 95% CI, 0.83 to 1.06; P = 0.31). Conclusions: Antiinflammatory therapy targeting the interleukin-1β innate immunity pathway with canakinumab at a dose of 150 mg every 3 months led to a significantly lower rate of recurrent cardiovascular events than placebo, independent of lipid-level lowering. (Funded by Novartis; CANTOS ClinicalTrials.gov number, NCT01327846.
The large-scale structure of the halo of the Andromeda galaxy II. Hierarchical structure in the Pan-Andromeda Archaeological Survey
The Pan-Andromeda Archaeological Survey is a survey of square degrees
centered on the Andromeda (M31) and Triangulum (M33) galaxies that has provided
the most extensive panorama of a galaxy group to large projected
galactocentric radii. Here, we collate and summarise the current status of our
knowledge of the substructures in the stellar halo of M31, and discuss
connections between these features. We estimate that the 13 most distinctive
substructures were produced by at least 5 different accretion events, all in
the last 3 or 4 Gyrs. We suggest that a few of the substructures furthest from
M31 may be shells from a single accretion event. We calculate the luminosities
of some prominent substructures for which previous estimates were not
available, and we estimate the stellar mass budget of the outer halo of M31. We
revisit the problem of quantifying the properties of a highly structured
dataset; specifically, we use the OPTICS clustering algorithm to quantify the
hierarchical structure of M31's stellar halo, and identify three new faint
structures. M31's halo, in projection, appears to be dominated by two
`mega-structures', that can be considered as the two most significant branches
of a merger tree produced by breaking M31's stellar halo into smaller and
smaller structures based on the stellar spatial clustering. We conclude that
OPTICS is a powerful algorithm that could be used in any astronomical
application involving the hierarchical clustering of points. The publication of
this article coincides with the public release of all PAndAS data products.Comment: Accepted for publication in the Astrophysical Journal. 51 pages, 24
figures, 5 tables. Some figures have degraded resolution. All PAndAS data
products are available via the CADC at
http://www.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/en/community/pandas/query.html
where you can also find a version of the paper with full resolution figure
The seeds of divergence: the economy of French North America, 1688 to 1760
Generally, Canada has been ignored in the literature on the colonial origins of divergence with most of the attention going to the United States. Late nineteenth century estimates of income per capita show that Canada was relatively poorer than the United States and that within Canada, the French and Catholic population of Quebec was considerably poorer. Was this gap long standing? Some evidence has been advanced for earlier periods, but it is quite limited and not well-suited for comparison with other societies.
This thesis aims to contribute both to Canadian economic history and to comparative work on inequality across nations during the early modern period. With the use of novel prices and wages from Quebec—which was then the largest settlement in Canada and under French rule—a price index, a series of real wages and a measurement of Gross Domestic Product (GDP) are constructed. They are used to shed light both on the course of economic development until the French were defeated by the British in 1760 and on standards of living in that colony relative to the mother country, France, as well as the American colonies.
The work is divided into three components. The first component relates to the construction of a price index. The absence of such an index has been a thorn in the side of Canadian historians as it has limited the ability of historians to obtain real values of wages, output and living standards. This index shows that prices did not follow any trend and remained at a stable level. However, there were episodes of wide swings—mostly due to wars and the monetary experiment of playing card money. The creation of this index lays the foundation of the next component.
The second component constructs a standardized real wage series in the form of welfare ratios (a consumption basket divided by nominal wage rate multiplied by length of work year) to compare Canada with France, England and Colonial America. Two measures are derived. The first relies on a “bare bones” definition of consumption with a large share of land-intensive goods. This measure indicates that Canada was poorer than England and Colonial America and not appreciably richer than France. However, this measure overestimates the relative position of Canada to the Old World because of the strong presence of land-intensive goods. A second measure is created using a “respectable” definition of consumption in which the basket includes a larger share of manufactured goods and capital-intensive goods. This second basket better reflects differences in living standards since the abundance of land in Canada (and Colonial America) made it easy to achieve bare subsistence, but the scarcity of capital and skilled labor made the consumption of luxuries and manufactured goods (clothing, lighting, imported goods) highly expensive. With this measure, the advantage of New France over France evaporates and turns slightly negative. In comparison with Britain and Colonial America, the gap widens appreciably. This element is the most important for future research. By showing a reversal because of a shift to a different type of basket, it shows that Old World and New World comparisons are very sensitive to how we measure the cost of living. Furthermore, there are no sustained improvements in living standards over the period regardless of the measure used. Gaps in living standards observed later in the nineteenth century existed as far back as the seventeenth century. In a wider American perspective that includes the Spanish colonies, Canada fares better.
The third component computes a new series for Gross Domestic Product (GDP). This is to avoid problems associated with using real wages in the form of welfare ratios which assume a constant labor supply. This assumption is hard to defend in the case of Colonial Canada as there were many signs of increasing industriousness during the eighteenth and nineteenth centuries. The GDP series suggest no long-run trend in living standards (from 1688 to circa 1765). The long peace era of 1713 to 1740 was marked by modest economic growth which offset a steady decline that had started in 1688, but by 1760 (as a result of constant warfare) living standards had sunk below their 1688 levels. These developments are accompanied by observations that suggest that other indicators of living standard declined. The flat-lining of incomes is accompanied by substantial increases in the amount of time worked, rising mortality and rising infant mortality. In addition, comparisons of incomes with the American colonies confirm the results obtained with wages— Canada was considerably poorer.
At the end, a long conclusion is provides an exploratory discussion of why Canada would have diverged early on. In structural terms, it is argued that the French colony was plagued by the problem of a small population which prohibited the existence of scale effects. In combination with the fact that it was dispersed throughout the territory, the small population of New France limited the scope for specialization and economies of scale. However, this problem was in part created, and in part aggravated, by institutional factors like seigneurial tenure. The colonial origins of French America’s divergence from the rest of North America are thus partly institutional