Optimum guidance law development

Issued as Monthly technical reports no. 1-6, Project no. A-348

Carnap, Tarski, and Quine's Year Together: Logic, Science, and Mathematics

During the academic year 1940-1941, several giants of analytic philosophy congregated at Harvard: Russell, Tarski, Carnap, Quine, Hempel, and Goodman were all in residence. This group held both regular public meetings as well as private conversations. Carnap took detailed diction notes that give us an extensive record of the discussions at Harvard that year. Surprisingly, the most prominent question in these discussions is: if the number of physical items in the universe is finite (or possibly finite), what form should the logic and mathematics in science take? This question is closely connected to an abiding philosophical problem, one that is of central philosophical importance to the logical empiricists: what is the relationship between the logico-mathematical realm and the natural, material realm? This problem continues to be central to analytic philosophy of logic, mathematics, and science. My dissertation focuses on three issues connected with this problem that dominate the Harvard discussions: nominalism, the unity of science, and analyticity. I both reconstruct the lines of argument represented in Harvard discussions and relate them to contemporary treatments of these issues

Improving regional ozone modeling through systematic evaluation of errors using the aircraft observations during the International Consortium for Atmospheric Research on Transport and Transformation

During the operational phase of the ICARTT field experiment in 2004, the regional air quality model STEM showed a strong positive surface bias and a negative upper troposphere bias (compared to observed DC-8 and WP-3 observations) with respect to ozone. After updating emissions from NEI 1999 to NEI 2001 (with a 2004 large point sources inventory update), and modifying boundary conditions, low-level model bias decreases from 11.21 to 1.45 ppbv for the NASA DC-8 observations and from 8.26 to −0.34 for the NOAA WP-3. Improvements in boundary conditions provided by global models decrease the upper troposphere negative ozone bias, while accounting for biomass burning emissions improved model performance for CO. The covariances of ozone bias were highly correlated to NOz, NOy, and HNO3 biases. Interpolation of bias information through kriging showed that decreasing emissions in SE United States would reduce regional ozone model bias and improve model correlation coefficients. The spatial distribution of forecast errors was analyzed using kriging, which identified distinct features, which when compared to errors in postanalysis simulations, helped document improvements. Changes in dry deposition to crops were shown to reduce substantially high bias in the forecasts in the Midwest, while updated emissions were shown to account for decreases in bias in the eastern United States. Observed and modeled ozone production efficiencies for the DC-8 were calculated and shown to be very similar (7.8) suggesting that recurring ozone bias is due to overestimation of NOx emissions. Sensitivity studies showed that ozone formation in the United States is most sensitive to NOx emissions, followed by VOCs and CO. PAN as a reservoir of NOx can contribute to a significant amount of surface ozone through thermal decomposition

Dive Behavior of Eastern Chukchi Beluga Whales (Delphinapterus leucas), 1998–2008

We provide an exploratory description of the dive behavior of 23 beluga whales of the eastern Chukchi Sea stock, tagged with satellite-linked time and depth recorders at Point Lay, Alaska, between 1998 and 2007. Because of differences in how transmitters were parameterized, we analyzed data from tags deployed from 1998 to 2002 (n = 20 tags) and data from tags deployed in 2007 (n = 3 tags) separately. Using cluster analysis, we found three basic dive types in the 1998–2002 dataset. “Shallow” diving behavior was characterized by dives mostly 50 m in depth. “Intermediate” diving behavior was characterized by having one mode near the surface and a second mode near 250 m. “Deep” diving behavior was characterized by having one mode near the surface and a second mode more than 400 m from the surface. The average number of dives per hour ranged from 5.1 (SD = 2.1) to 9.8 (SD = 2.9) across dive types, with the fewest dives per hour in the deep diving category. In general, duration of dives ranged from 1 to 18 minutes; however, dives up to 21 minutes occurred in the deepest diving category. We found little evidence that dive behavior of the belugas in our sample varied by sex or age. In general, belugas dove more deeply in the eastern Beaufort Sea than in the western Beaufort or Chukchi Seas. The depths to which belugas most commonly dive in Barrow Canyon and along the Beaufort shelf break (200–300 m) correspond to the boundary where colder Pacific water overlies warmer Atlantic water, which is probably where Arctic cod (Boreogadus saida) are most dense. Diving depths within the Arctic Basin suggest that belugas are foraging mostly within the warm layer of Atlantic Water (~200–1000 m).Nous dressons une description exploratoire du comportement de plongée de 23 bélugas du cheptel de l’est de la mer des Tchouktches dotés de marqueurs d’enregistreurs satellitaires de profondeur temporelle à Point Lay, en Alaska, entre 1998 et 2007. En raison des différences de paramétrage des transmetteurs, nous avons analysé séparément les données de marqueurs déployés de 1998 à 2002 (n = 20 marqueurs) et les données de marqueurs déployés en 2007 (n = 3 marqueurs). Grâce à une analyse par grappes, nous avons trouvé trois types de plongée fondamentaux dans l’ensemble des données de 1998 à 2002. Le comportement de plongée « en eau peu profonde » était principalement caractérisé par des plongées de 50 m de profondeur. Le comportement de plongée « intermédiaire » était caractérisé par un mode de plongée près de la surface et un autre mode à près de 250 m. Le comportement de plongée « en profondeur » était caractérisé par un mode de plongée près de la surface et un deuxième mode à plus de 400 m de la surface. Le nombre moyen de plongées à l’heure variait de 5,1 (écart-type = 2,1) à 9,8 (écart-type = 2,9) pour ce qui est de tous les types de plongée, la catégorie des plongées en profondeur ayant enregistré le moins grand nombre de plongées. En général, la durée des plongées durait de 1 à 18 minutes, mais cela dit, certaines des plongées en profondeur ont duré jusqu’à 21 minutes. Nous avons trouvé peu d’indices portant à croire que le comportement de plongée des bélugas de notre échantillon variait en fonction du sexe ou de l’âge. De manière générale, les bélugas plongeaient plus en profondeur dans l’est de la mer de Beaufort que dans l’ouest de la mer de Beaufort ou dans la mer des Tchouktches. Les profondeurs auxquelles les bélugas plongent le plus souvent dans le canyon Barrow et le long du rebord continental de Beaufort (de 200 à 300 m) correspondent à la limite où l’eau plus froide du Pacifique se superpose à l’eau plus chaude de l’Atlantique, là où la morue polaire (Boreogadus saida) est plus dense. Dans le bassin arctique, la profondeur des plongées suggère que les bélugas s’alimentent surtout dans la couche tempérée d’eau de l’Atlantique (~200 à 1 000 m)

Newly diagnosed atrial fibrillation and hospital utilization in heart failure:a nationwide cohort study

AIMS: Atrial fibrillation (AF) constitutes a major burden to health services, but the importance of incident AF in patients with heart failure (HF) is unclear. We examined the associations between incident AF and hospital utilization in patients with HF. METHODS AND RESULTS: In a nationwide matched‐cohort study of HF patients, we identified patients diagnosed with incident AF between 2008 and 2018 in the Danish Heart Failure Registry (N = 4463), and we compared them to matched referents without AF (N = 17 802). Incident AF was associated with a multivariable‐adjusted 4.8‐fold increase (95% CI 4.1–5.6) and 4.3‐fold increase (95% CI 3.9–4.8) in the cumulative incidence of inpatient and outpatient contacts within 30 days, respectively. At 1 year, the cumulative incidence ratios were 1.8 (95% CI 1.7–1.9) and 1.4 (95% CI 1.4–1.5). Incident AF was also associated with increases in the total numbers of inpatient and outpatient hospital contacts within 30 days (multivariable‐adjusted rate ratio 1.4, 95% CI 1.4–1.5, and 1.6, 95% CI 1.6–1.7, respectively). At 1 year, the ratios were 2.2 (95% CI 2.1–2.3) and 2.0 (95% CI 1.9–2.1). The multivariable‐adjusted proportion of bed‐day use among HF patients with incident AF was 10.9‐fold (95% CI 9.3–12.9) higher at 30 days and 5.3‐fold (95% CI 4.3–6.4) higher at 1 year compared with AF‐free referents. CONCLUSIONS: Incident AF in HF is associated with earlier hospital contact, more hospital contacts, and more hospital bed‐days. More evidence on interventions that may prevent the risk and subsequent burden of AF in HF is urgently needed

What's in a heuristic? Commentary on Sunstein, C.

The term “moral heuristic” as used by Sunstein seeks to bring together various traditions. However, there are significant differences between uses of the term “heuristic” in the cognitive and the social psychological research, and these differences are accompanied by very distinct evidential criteria. We suggest the term “moral heuristic” should refer to processes, which means that further evidence is required