Moments of inertia of several airplanes

This paper, which is the first of a series presenting the results of such measurements, gives the momental ellipsoids of ten army and naval biplanes and one commercial monoplane. The data were obtained by the use of a pendulum method, previously described. The moments of inertia are expressed in coefficient as well as in dimensional form, so that those for airplanes of widely different weights and dimensions can be compared

Forecast Combination with Multiple Models and Expert Correlations

Combining multiple forecasts in order to generate a single, more accurate one is a well-known approach. A simple average of forecasts has been found to be robust despite theoretically better approaches, increasing availability in the number of expert forecasts, and improved computational capabilities. The dominance of a simple average is related to the small sample sizes and to the estimation errors associated with more complex methods. We study the role that expert correlation, multiple experts, and their relative forecasting accuracy have on the weight estimation error distribution. The distributions we find are used to identify the conditions when a decision maker can confidently estimate weights versus using a simple average. We also propose an improved expert weighting approach that is less sensitive to covariance estimation error while providing much of the benefit from a covariance optimal weight. These two improvements create a new heuristic for better forecast aggregation that is simple to use. This heuristic appears new to the literature and is shown to perform better than a simple average in a simulation study and by application to economic forecast data

An alternate algorithm for correction of the scanning multichannel microwave radiometer polarization radiances using Nimbus-7 observed data

The manner in which Nimbus-7 scanning multichannel microwave radiometer (SMMR) scan radiance data was used to determine its operational characteristics is described. The predicted SMMR scan radiance was found to be in disagreement at all wavelengths with a large area of average measured ocean radiances. A modified model incorporating a different phase shift for each of the SMMR horizontal and vertical polarization channels was developed and found to provide good data correlation. Additional study is required to determine the validity and accuracy of this model

Contribution of growth hormone-releasing hormone and somatostatin to decreased growth hormone secretion in elderly men

Objective. The pathophysiology of the decline in circulating growth hormone (GH) concentrations that may occur with ageing remains elusive. We have investigated the potential contributions of decreased endogenous GH-releasing hormone (GHRH) and increased somatostatin secretion to this phenomenon.Design and methods. The strategy used was to stimulate GH secretion in 8 young (20 - 24 years old, body mass index (BMI) 22.8 ± 2.8 kg/m2) and 8 elderly (68- 82 years old, BMI 23.4 ± 1.6 kg/m2) male subjects on separate occasions by means of: (i) intravenous bolus 0.5 ).lg/kg D-Ala2 GHRH(1-29)-NH alone; (ii) 0.5 μg/kg GHRH after pretreatment with two oral doses of 50 mg atenolol (to inhibit somatostatin secretion); (iii) 1.25 mg oral bromocriptine alone (to increase endogenous GHRH and/or inhibit somatostatin); (iv) 50 mg oral atenolol plus 1.25 mg oral bromocriptine; and (v) 0.5 μg/kg GHRH after pre-treatment with 1.25 mg oral bromocriptine.Results. The elderly men had a significantly lower peak and area under curve (AUC) GH response to intravenous GHRH when compared with 8 young men (peak 3.1 ± 1.0 ng/ml v. 21.6 ± 5.0 ng/ ml, AUC 205 ±56 ng/ ml/min v.1 315 ± 295 ng/ ml/ min, P < 0.05). Pre-treatment with atenolol before GHRH administration produced no significant increase in peak and AUC GH response in both groups, whlch remained lower in the elderly men than in their young counterparts (peak 5.5 ±1.8 ng/ ml v. 29.3 ± 7.0 ng/ml, AUC 327 ± 90 ng/ml/min v. 2 017 ± 590 ng/ ml/min, P < 0.05). Bromocriptine alone did not cause a significant rise in GH concentration in either elderly or young subjects (peak 3.1 ± 1.1 v. 8.8 ± 3.2 ng/ ml, P > 0.05). When atenolol was administered before bromocriptine, both groups responded but the elderly subjects had a significantly greater peak and AUC response (peak 3.6 ± 0.7 v. 10:7 ± 2.1 ng/ ml; AUC 191 ± 39 v. 533 ± 125 ng/ ml/ min, P < 0.05). Bromocriptine given before GHRH failed to potentiate GHRH action on GH release in either group. Of 5 elderly men who tmderwent further evaluation of GH secretory ability, 2 subjects had GH levels > 10 ng/ rnl, either basally or after intravenous GHRH. The remaining 3 had an initially impaired GH response to bolus intravenous GHRH. After 100 μg GHRH subcutaneously twice daily for up to 2 weeks the GH responses to intravenous bolus GHRH (0.5μg /kg) were reassessed. One exhibited a normal response (> 10 ng/ rnl) after 1 week of daily GHRH treatment, another had a nearnormal response after 2 weeks (9.7 ng/ rnl), while the third still had an impaired response by the end of the 2-week treatment period (3.2 ng/ ml).Conclusions. The restoration of endogenous GH secretion in these elderly subjects by means of GHRH priming, and the failure of manipulation of somatostatinergic tone to restore a normal GH response to GHRH suggests that somatotroph atrophy due to a reduction in endogenous GHRH secretion is the principal cause of the diminished GH secretion with ageing

Dynamic expressivity with static optimization for streaming languages

Developers increasingly use streaming languages to write applications that process large volumes of data with high throughput. Unfortunately, when picking which streaming language to use, they face a difficult choice. On the one hand, dynamically scheduled languages allow developers to write a wider range of applications, but cannot take advantage of many crucial optimizations. On the other hand, statically scheduled languages are extremely performant, but have difficulty expressing many important streaming applications. This paper presents the design of a hybrid scheduler for stream processing languages. The compiler partitions the streaming application into coarse-grained subgraphs separated by dynamic rate boundaries. It then applies static optimizations to those subgraphs. We have implemented this scheduler as an extension to the StreamIt compiler. To evaluate its performance, we compare it to three scheduling techniques used by dynamic systems (OS thread, demand, and no-op) on a combination of micro-benchmarks and real-world inspired synthetic benchmarks. Our scheduler not only allows the previously static version of StreamIt to run dynamic rate applications, but it outperforms the three dynamic alternatives. This demonstrates that our scheduler strikes the right balance between expressivity and performance for stream processing languages.National Science Foundation (U.S.) (CCF-1162444

Overt hypoadrenalism is uncommon in patients with stage 3 and 4 bronchogenic carcinoma

Introduction. Lung cancer is the leading cause of cancer mortality in most countries. The adrenal glands are common sites of metastatic lung cancer as approximately 40% of subjects with stage 4 bronchogenic carcinoma have adrenal metastases. The prevalence of biochemical hypoadrenalism is, however, remarkably poorly documented.Objectives. Our study aimed to determine the prevalence of primary hypoadrenalism, as defined by a subnormal cortisol response to the 250 µg adrenocorticotrophic hormone (ACTH) stimulation test, in patients with stage 3 and 4 lung cancer.Methods. Thirty patients with stage 3 and 4 bronchogenic carcinoma were prospectively recruited from the bronchus clinic. Demographic data and electrolytes were recorded and each patient had a 250 µg ACTH stimulation test to determine the prevalence of overt adrenal insufficiency, defined as a +30 minute cortisol of less than 550 nmol/l.Results. The median age and quartile deviation was 62 (10) years and the median basal cortisol was 429.5 (321) nmol/l. The median peak cortisol was 828.5 (342) nmol/l (range 536 - 1 675 nmol/l). Twenty-eight patients (93.3%) had an appropriate rise of cortisol to greater than 550 nmol/l following 250 µg ACTH stimulation. Two patients (6.7%) had mild primary adrenal failure with a peak cortisol between 500 and 550 nmol/l associated with a raised plasma ACTH concentration (131.4 and 10.5 pmol/l, normal 2.2 - 10 pmol/l). Twenty-eight patients (92.9%) were normonatraemic, while the two hyponatraemic patients had biochemical evidence of the syndrome of inappropriate antidiuretic hormone secretion.Conclusion. In conclusion, despite evidence that the adrenal glands of patients with disseminated bronchogenic carcinoma are frequently affected by metastatic disease, biochemical evidence of clinically significant hypoadrenalism is relatively uncommon and is not accurately predicted by electrolyte abnormalities

Formation of submarine lava channel textures : insights from laboratory simulations

Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 111 (2006): B03104, doi:10.1029/2005JB003796.Laboratory simulations using polyethylene glycol (PEG) extruded at a constant rate and temperature into a tank with a uniform basal slope and filled with a cold sucrose solution generate channels that are defined by stationary levees and mobile flow interiors. These laboratory channels consistently display the following surface textures in the channel: smooth, folded, lineated, and chaotic. In the simulations, we can observe specific local conditions including flow rate, position within the channel, and time that combine to develop each texture. The textures in PEG flows form due to relative differences in shear forces between the PEG crust and the underlying liquid wax. Minimal shear forces form smooth crust, whereas folded crust forms when the shear is sufficiently high to cause ductile deformation. Brittle deformation of solid PEG creates a chaotic texture, and lineated crust results from shear forces along the channel-levee margin. We observe similar textures in submarine lava channels with sources at or near the Axial Summit Trough of the East Pacific Rise between 9° and 10°N. We mapped the surface textures of nine submarine lava channels using high-resolution digital images collected during camera tows. These textural maps, along with observations of the formation of similar features in analog flows, reveal important information about the mechanisms occurring across the channel during emplacement, including relative flow velocity and shear stress.The cruise was funded by a grant to WHOI from the National Science Foundation (NSF) OCE-9819261, with additional funding provided by WHOI thorough the Vetlesen Foundation. The PEG experiments were funded by NSF OCE-0425073 in a grant to Tracy Gregg

Early phases of different types of isolated neutron star

Two Galactic isolated strong X-ray pulsars seem to be in the densest environments compared to other types of Galactic pulsar. X-ray pulsar J1846-0258 can be in an early phase of anomalous X-ray pulsars and soft gamma repeaters if its average braking index is ~1.8-2.0. X-ray pulsar J1811-1925 must have a very large average braking index (n~11) if this pulsar was formed by SN 386AD. This X-ray pulsar can be in an early phase of evolution of the radio pulsars located in the region P~50-150 ms and \.{P}~10$^{-14}-10^{-16}$ s/s of the P-\.{P} diagram. X-ray/radio pulsar J0540-69 seems to be evolving in the direction to the dim isolated thermal neutron star region on the P-\.{P} diagram. Possible progenitors of different types of neutron star are also discussed.Comment: to appear in the International Journal of Modern Physics