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

The Sloan Digital Sky Survey-II Supernova Survey: Search Algorithm and Follow-up Observations

The Sloan Digital Sky Survey-II Supernova Survey has identified a large number of new transient sources in a 300 sq. deg. region along the celestial equator during its first two seasons of a three-season campaign. Multi-band (ugriz) light curves were measured for most of the sources, which include solar system objects, Galactic variable stars, active galactic nuclei, supernovae (SNe), and other astronomical transients. The imaging survey is augmented by an extensive spectroscopic follow-up program to identify SNe, measure their redshifts, and study the physical conditions of the explosions and their environment through spectroscopic diagnostics. During the survey, light curves are rapidly evaluated to provide an initial photometric type of the SNe, and a selected sample of sources are targeted for spectroscopic observations. In the first two seasons, 476 sources were selected for spectroscopic observations, of which 403 were identified as SNe. For the Type Ia SNe, the main driver for the Survey, our photometric typing and targeting efficiency is 90%. Only 6% of the photometric SN Ia candidates were spectroscopically classified as non-SN Ia instead, and the remaining 4% resulted in low signal-to-noise, unclassified spectra. This paper describes the search algorithm and the software, and the real-time processing of the SDSS imaging data. We also present the details of the supernova candidate selection procedures and strategies for follow-up spectroscopic and imaging observations of the discovered sources.Comment: Accepted for publication in The Astronomical Journal (66 pages, 13 figures); typos correcte

The pursuit of happiness: the social and scientific origins of Hans Selye’s natural philosophy of life

© The Author(s) 2012. Open access article.In 1956, Hans Selye tentatively suggested that the scientific study of stress could ‘help us to formulate a precise program of conduct’ and ‘teach us the wisdom to live a rich and meaningful life’. Nearly two decades later, Selye expanded this limited vision of social order into a full-blown philosophy of life. In Stress without Distress, first published in 1974, he proposed an ethical code of conduct designed to mitigate personal and social problems. Basing his arguments on contemporary understandings of the biological processes involved in stress reactions, Selye referred to this code as ‘altruistic egotism’. This article explores the origins and evolution of Selye’s ‘natural philosophy of life’, analysing the links between his theories and adjacent intellectual developments in biology, psychosomatic and psychosocial medicine, cybernetics and socio-biology, and situating his work in the broader cultural framework of modern western societies.Wellcome Trus

Alleviating the Thucydides’ Trap through welfare state dependence:How the funding needs of the Western welfare state can influence multilateral relations with China

The dual threat of a US-China confrontation and the rise of populism in the West due, in part, to the gradual decay of the welfare state, paint an ominous picture for the future of the post-war status quo of ever-expanding prosperity. Hegemonic competition between the incumbent superpower (the USA) and the challenger (China) framed as the Thucydides’ Trap and adverse demographic and financial trends are the main causes behind both crises. In this paper we argue that amidst deteriorating demographics, the sustainability of the Western welfare state could be significantly enhanced by positioning Western institutional investments in the regions across India and South East Asia - areas with strong modernization dynamics and the world’s nascent most populous middle class. Such a policy could generate long-term higher risk-adjusted returns for Western pension funds, especially if Western investors look for complementarities with China’s Belt and Road Initiative (BRI). The proposed geographical calibration in Western institutional investments could lead to a relationship of strong reciprocal dependence between economic and social growth in the target regions, exports of Chinese construction and financial capacity, and Western welfare state viability. We call the suggested policy the “welfare state dependence” hypothesis. The key objective of the hypothesis is the promotion of peaceful economic and geo-political co-existence in Eurasia through rational re-alignment of the incentives of Western polities with Eurasian growth. But to make this new approach feasible a number of BRI policy reforms that supports its multilateralization are required

Recent Developments at the Apache Point Lunar Laser Ranging Station

22nd International Workshop on Laser Ranging, Guadalajara, Spain, November 07-11, 2022.The Apache Point Lunar Laser Ranging Station (formerly the Apache Point Observatory Lunar Laser-ranging Operation, or “APOLLO”) became part of the NASA Space Geodesy Network at the beginning of 2021. In conjunction with the former APOLLO team, best practices were established regarding observation and processing of data into normal points. A quality control process to identify centimeter-level biases was introduced, archival procedures were adjusted to match version 2 of the Consolidated Range Data format, and a fully reduced 2021 dataset was published to the Crustal Dynamics Data Information System’s database. The APOLLO experiment has achieved median range precision at the (1-3) millimeter level for many years, yet comparisons of measurements against models are nearly an order-of-magnitude larger. Model-measurement disagreement raises the question of whether APOLLO suffers from gross systematic inaccuracies or if models are incomplete in some manner. In 2016, the APOLLO team added an Absolute Calibration System (ACS) consisting of a high-repetition-rate (80 MHz) short-pulsed (< 10 ps) laser that is locked to a cesium clock. The ACS delivers “truth” photons to the APOLLO detector at well-known time intervals which provides an independent assessment of the accuracy of the APOLLO system and an avenue for correcting range data in-situ. ACS results suggest systematic errors are reduced to ≤ 1 mm such that both the accuracy and precision of the data are at the ~ 1 mm level.https://ilrs.gsfc.nasa.gov/lw22/Program/index.htm

Functional diversity in reef fish assemblages in the Parque Nacional Sistema Arrecifal Veracruzano, Mexico: Temporal and spatial changes

The Parque Nacional Sistema Arrecifal Veracruzano (hereafter called PNSAV) is the largest coral reef extension in the central region of the Gulf of Mexico. These reefs are unique since they have developed near a coastal environment that is directly influenced by the discharges of Veracruz city, the rivers located on the continental shelf, and the port of Veracruz. This study evaluates the functional diversity, in terms of richness, evenness, and divergence, of the PNSAV fish community. We were interested in quantifying any similarities or differences in functional diversity metrics when one examines reef fish assemblages on a single reef or joint reef subsystems; thus, is there a difference based on scale? A total of 297 fish assemblages were observed in seven PNSAV reefs between May 2006 and April 2021. Significant differences were found in the Functional Richness of the assemblages between subsystems, years, and reef-depth interaction, but none were found among the reefs, or between seascapes. The Functional Diversity presented annual mean values between 0.83 (sd= 0.085) and 0.90 (sd= 0.068) and did not show statistical differences between years, seascape, or reefs. In contrast, statistical differences were found between subsystems, and depth level and the seascape-depth interaction. The annual mean Functional Evenness values ranged between 0.34 (sd= 0.128) and 0.44 (sd= 0.060), and significant differences were detected between years, reef, and reefs-depth level interaction, but no difference were found between subsystems. Reef-fish diversity was greater within the north coral reef subsystem than the southern of the PNSAV. There were no overall tendencies for increased functional diversity throughout the time during this study.</jats:p