A technique using a nonlinear helicopter model for determining trims and derivatives

A technique is described for determining the trims and quasi-static derivatives of a flight vehicle for use in a linear perturbation model; both the coupled and uncoupled forms of the linear perturbation model are included. Since this technique requires a nonlinear vehicle model, detailed equations with constants and nonlinear functions for the CH-47B tandem rotor helicopter are presented. Tables of trims and derivatives are included for airspeeds between -40 and 160 knots and rates of descent between + or - 10.16 m/sec (+ or - 200 ft/min). As a verification, the calculated and referenced values of comparable trims, derivatives, and linear model poles are shown to have acceptable agreement

Rethinking our understanding of the pathogenesis of necrotic enteritis in chickens

For decades, low doses of antibiotics have been used widely in animal production to promote growth. However, there is a trend to reduce this use of antibiotics in feedstuffs, and legislation is now in place in Europe to prohibit their use in this way. As a consequence, economically important diseases, such as necrotic enteritis (NE) of chickens, that are caused by Clostridium perfringens have become more prevalent. Recent research is creating a paradigm shift in our understanding of the pathogenesis of NE and is now providing information that will be necessary to monitor and control the incidence of NE in poultry

Forward osmosis with an algal draw solution for wastewater concentrating and polishing

Forward osmosis (FO) is an emerging wastewater treatment technology capable of high solute rejection by separating water from wastewater across a semi-permeable membrane. However, there is always leaking of ammonium from the feed solution (FS) to the draw solution (DS). Parallel bench-scale FO systems were operated with synthetic municipal wastewater as an FS. Both systems had a synthetic seawater DS with one system also inoculated by an algal species (Chlorella Vulgaris) to act as an absorbent (polishing agent). At the completion of three consecutive trials (lasting a total of three days), ammonium removal efficiency in the algae-based FO system improved by 35.4 [plus or minus] 4.6%. Throughout the fed-batch operation in the DS chamber, the algal biomass concentration was maintained at 606 [plus or minus] 29 mg/L due to simultaneous algal growth and dilution. The water flux gradually decreased from an average initial flux of 16.5 LMH to an average of 8.2 LMH after each trial operation, with an average water flux of 11.63 [plus or minus] 0.49 LMH compared to 12.05 [plus or minus] 0.35 LMH in the system without algae. Meanwhile, organic matter and phosphorus were completely retained in the FS in both systems. At the completion of each trial operation, the concentrations of chemical oxygen demand (COD) and phosphorus in the synthetic wastewater increased by an average of 44%. This work highlights the dual-benefit applications of algae-based FO with improved effluent water quality and concentrated wastewater COD and phosphorus for potential water resource recovery and water reuse.Includes bibliographical reference

The Electron Temperature Gradient in the Galactic Disk

We derive the electron temperature gradient in the Galactic disk using a sample of HII regions that spans Galactocentric distances 0--17 kpc. The electron temperature was calculated using high precision radio recombination line and continuum observations for more than 100 HII regions. Nebular Galactocentric distances were calculated in a consistent manner using the radial velocities measured by our radio recombination line survey. The large number of nebulae widely distributed over the Galactic disk together with the uniformity of our data provide a secure estimate of the present electron temperature gradient in the Milky Way. Because metals are the main coolants in the photoionized gas, the electron temperature along the Galactic disk should be directly related to the distribution of heavy elements in the Milky Way. Our best estimate of the electron temperature gradient is derived from a sample of 76 sources for which we have the highest quality data. The present gradient in electron temperature has a minimum at the Galactic Center and rises at a rate of 287 +/- 46 K/kpc. There are no significant variations in the value of the gradient as a function of Galactocentric radius or azimuth. The scatter we find in the HII region electron temperatures at a given Galactocentric radius is not due to observational error, but rather to intrinsic fluctuations in these temperatures which are almost certainly due to fluctuations in the nebular heavy element abundances. Comparing the HII region gradient with the much steeper gradient found for planetary nebulae suggests that the electron temperature gradient evolves with time, becoming flatter as a consequence of the chemical evolution of the Milky Way's disk.Comment: 43 pages, 9 figures (accepted for publication in the ApJ

A retrospective review of the adverse effects of biological therapy and reasons for its discontinuation in a resource-limited setting

Background. Biological disease-modifying antirheumatic drug therapies have become the gold standard of treatment for refractory rheumatic conditions in well-resourced countries. There is a significant risk of infection and reactivation of latent infections, in particular tuberculosis, with the use of biological therapies. Their safety and reasons for discontinuation in a resource-limited environment are still unclear.Objectives. The primary objective was to describe the nature and frequency of adverse events as well as the main reason for discontinuation of biological treatment.Methods. We conducted a retrospective, descriptive folder review of all patients started on biological therapy for rheumatic conditions from November 2011 to December 2016.Results. A total of 31 patients were included. The rheumatic diseases included in the study were ankylosing spondylitis (AS) (35%), rheumatoid arthritis (RA) (19%), systemic lupus erythematosus (16%), juvenile idiopathic arthritis (13%), vasculitides (10%) and psoriatic arthritis (7%). Adverse events occurred in 26 patients (84%). Serious adverse events occurred in 14 patients (45%) with recurrent uveitis being the most common, occurring in 5 patients (16%). One patient developed pulmonary tuberculosis (PTB). Discontinuation or switching of biological therapy occurred in 13 patients (42%), with the main reasons being serious adverse events in 7 patients (23%) and treatment failure in 6 (19%). The median (interquartile range (IQR)) Bath Ankylosing Spondylitis Disease Activity Index score improved from 6.4 (5 - 7.4) to 2.8 (0.9 - 5.0), a statistically significant difference of –3.5 (p=0.001) (95% confidence interval (CI) –5.3 - –1.7) over a median (IQR) of 20 (9 - 30) months in the AS group. The median (IQR) Clinical Disease Activity Index score improved from 39 (34.5 - 43) to 21 (18.7 - 25.5), a statistically significant difference of –17.4 (p=0.044) (95% CI –34.1 - –0.7) over a median (IQR) of 39 (21 - 50) months in the RA group.Conclusions. Recurrent uveitis occurred in almost half of the patients with AS and was also the main reason for discontinuation of biological therapy. We did not document an increased risk of PTB. Disease activity scores showed significant improvement. The study is limited by the small number of patients on biological therapy, a reflection of the impact of severe resource constraints

Medication Darts Are Gaining in Popularity - Do They Affect Meat Quality? Are There Risks?

Livestock, such as beef cattle or post-weaned dairy cattle that are not yet milking, are often relatively “tame” (sometimes the term tame may not apply very well) and can be readily approached within a few feet. However, without adequate restraint facilities or enough personnel, actually treating the livestock is often difficult and can become frustrating and dangerous to people and animals. A solution to this problem, which is being rapidly and increasingly adopted, is the use of medication darts. Nevertheless, many in the cattle industry are raising some concerns. What are some of the characteristics of medication darts? Is there any reason for concern about meat and carcass quality associated with their use

Risso's dolphins alter daily resting pattern in response to whale watching at the Azores

Peer reviewedPreprin

Downscale cascades in tracer transport test cases: an intercomparison of the dynamical cores in the Community Atmosphere Model CAM5

The accurate modeling of cascades to unresolved scales is an important part of the tracer transport component of dynamical cores of weather and climate models. This paper aims to investigate the ability of the advection schemes in the National Center for Atmospheric Research's Community Atmosphere Model version 5 (CAM5) to model this cascade. In order to quantify the effects of the different advection schemes in CAM5, four two-dimensional tracer transport test cases are presented. Three of the tests stretch the tracer below the scale of coarse resolution grids to ensure the downscale cascade of tracer variance. These results are compared with a high resolution reference solution, which is simulated on a resolution fine enough to resolve the tracer during the test. The fourth test has two separate flow cells, and is designed so that any tracer in the western hemisphere should not pass into the eastern hemisphere. This is to test whether the diffusion in transport schemes, often in the form of explicit hyper-diffusion terms or implicit through monotonic limiters, contains unphysical mixing. <br><br> An intercomparison of three of the dynamical cores of the National Center for Atmospheric Research's Community Atmosphere Model version 5 is performed. The results show that the finite-volume (CAM-FV) and spectral element (CAM-SE) dynamical cores model the downscale cascade of tracer variance better than the semi-Lagrangian transport scheme of the Eulerian spectral transform core (CAM-EUL). Each scheme tested produces unphysical mass in the eastern hemisphere of the separate cells test

Stratospheric Data Analysis System (STRATAN)

A state of the art stratospheric analyses using a coupled stratosphere/troposphere data assimilation system is produced. These analyses can be applied to stratospheric studies of all types. Of importance to this effort is the application of the Stratospheric Data Analysis System (STRATAN) to constituent transport and chemistry problems