6,970 research outputs found
RECENT ADVANCES IN VETERINARY ENTOMOLOGY1
The advances during the last 15 years in our knowledge of the biology and control of arthropod pests of livestock and vectors of animal disease agents exceed those made in any similar period in past history. Before 1942 we relied mainly on rotenone, pyrethrum, the thiocyanates, and the arsenicals for control of lice, ticks, mites, biting flies, and cattle grubs. While effective against some pests under certain conditions, these materials were not practical for wide-scale use and did not meet the public demand for better insecticides. Today we have highly effective and low-cost insecticides such as DDT, lindane, TDE, toxaphene, methoxychlor, chlordane, and synergized pyrethrum for control of livestock insects. Their use has saved the live stock grower many millions of dollars annually and has benefited the con sumer by making more and better animal products available.
Of almost equal importance to the development of the new insecticides are the contributions made to our knowledge of the biology and habits of several livestock insects and their transmission of agents of animal diseases. Many new ideas and approaches to studies on insect biology and control have been developed during the last few years. A good example of this is the unique method for the control of screw-worms by release of sterilized male flies over an area. The sterile males mate with the native females, but the eggs are infertile and thus reduce the numbers of screw-worms. Another ex ample of new trends is the promising research with insecticides that can be given internally to livestock for destruction of external pests. These studies will be discussed in detail in the following pages.
Although great progress has been made in the use of insecticides, two disturbing factors have arisen to cause worry as to the future efficiency of chemical means of control. The first is the increasing and widespread development of resistance of insects to insecticides, particularly to the chlorinated hydrocarbons. House flies have developed such a high degree of resistance to DDT and related materials that satisfactory control is impossible in most areas. Organic phosphorus insecticides have so far performed in a creditable manner in controlling house flies, but there are indications that these chemicals may eventually fail. As yet no reports on resistance of horn flies, horse flies, deer flies, stable flies, sheep keds, or lice of livestock have appeared
Debugging tasked Ada programs
The applications for which Ada was developed require distributed implementations of the language and extensive use of tasking facilities. Debugging and testing technology as it applies to parallel features of languages currently falls short of needs. Thus, the development of embedded systems using Ada pose special challenges to the software engineer. Techniques for distributing Ada programs, support for simulating distributed target machines, testing facilities for tasked programs, and debugging support applicable to simulated and to real targets all need to be addressed. A technique is presented for debugging Ada programs that use tasking and it describes a debugger, called AdaTAD, to support the technique. The debugging technique is presented together with the use interface to AdaTAD. The component of AdaTAD that monitors and controls communication among tasks was designed in Ada and is presented through an example with a simple tasked program
Discrete adjoint approximations with shocks
This paper is concerned with the formulation and discretisation of adjoint equations when there are shocks in the underlying solution to the original nonlinear hyperbolic p.d.e. For the model problem of a scalar unsteady one-dimensional p.d.e. with a convex flux function, it is shown that the analytic formulation of the adjoint equations requires the imposition of an interior boundary condition along any shock. A 'discrete adjoint' discretisation is defined by requiring the adjoint equations to give the same value for the linearised functional as a linearisation of the original nonlinear discretisation. It is demonstrated that convergence requires increasing numerical smoothing of any shocks. Without this, any consistent discretisation of the adjoint equations without the inclusion of the shock boundary condition may yield incorrect values for the adjoint solution
General Relativistic Radiative Transfer
We present a general method to calculate radiative transfer including
scattering in the continuum as well as in lines in spherically symmetric
systems that are influenced by the effects of general relativity (GR). We
utilize a comoving wavelength ansatz that allows to resolve spectral lines
throughout the atmosphere. The used numerical solution is an operator splitting
(OS) technique that uses a characteristic formal solution. The bending of
photon paths and the wavelength shifts due to the effects of GR are fully taken
into account, as is the treatment of image generation in a curved spacetime. We
describe the algorithm we use and demonstrate the effects of GR on the
radiative transport of a two level atom line in a neutron star like atmosphere
for various combinations of continuous and line scattering coefficients. In
addition, we present grey continuum models and discuss the effects of different
scattering albedos on the emergent spectra and the determination of effective
temperatures and radii of neutron star atmospheres
From 3D landscape visualization to environmental simulation: The contribution of sound to the perception of virtual environments
This research investigated the perceptual interaction of combining sound with 3D landscape visualizations. Images sourced from Google Earth at St. James's Park, London, UK, showing terrain only, terrain with built form or terrain with primarily vegetation were paired with four sound conditions using recordings from the park (i.e. ‘no sound’, anthropogenic, mechanical and natural). Perceived realism and preference were evaluated using a survey delivered via the Internet and in a controlled laboratory environment (N = 199 total). Analysis using repeated measures ANOVA indicated the interaction of sound and 3D visualizations significantly alters environmental perception both positively and negatively. Sounds and visuals that are congruent receive higher realism and preference ratings while the more incongruent the combination is, the lower the corresponding ratings. The lowest realism and preference ratings are given to visualizations showing terrain only combined with speech. The highest realism ratings overall correspond to visualization with built form combined with speech, and visualizations showing primarily vegetation paired with a birdcall. The absolute highest realism rating was for the visualization with primarily vegetation and some built form paired with speech, while the highest preference ratings correspond to visualizations showing vegetation paired with birdcall or no sound. Aural-visual data collected via the web-based survey was comparable to data collected in the laboratory and overall realism ratings for the Google Earth visualizations were low (e.g. below 3 on a 1–5 likert type scale). The results suggest there is an opportunity to increase experiential authenticity of 3D landscape visualizations with sound
Rigid open-cell polyurethane foam for cryogenic insulation
Lightweight polyurethane foam assembled in panels is effective spacer material for construction of self-evacuating multilayer insulation panels for cryogenic liquid tanks. Spacer material separates radiation shields with barrier that minimizes conductive and convective heat transfer between shields
Low-Density Granulocytes Are a Novel Immunopathological Feature in Both Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorder
Objective: To investigate whether low-density granulocytes (LDGs) are an immunophenotypic feature of patients with multiple sclerosis (MS) or neuromyelitis optica spectrum disorder (NMOSD).
Methods: Blood samples were collected from 20 patients with NMOSD and 17 patients with MS, as well as from 15 patients with Systemic Lupus Erythematosus (SLE) and 23 Healthy Donors (HD). We isolated peripheral blood mononuclear cells (PBMCs) with density gradient separation and stained the cells with antibodies against CD14, CD15, CD16, and CD45, and analyzed the cells by flow cytometry or imaging flow cytometry. We defined LDGs as CD14-CD15(high) and calculated their share in total PBMC leukocytes (CD45+) as well as the share of CD16(hi) LDGs. Clinical data on disease course, medication, and antibody status were obtained.
Results: LDGs were significantly more common in MS and NMOSD than in HDs, comparable to SLE samples (median values HD 0.2%, MS 0.9%, NMOSD 2.1%, SLE 4.3%). 0/23 of the HDs, but 17/20 NMOSD and 11/17 MS samples as well as 13/15 SLE samples had at least 0.7 % LDGs. NMOSD patients without continuous immunosuppressive treatment had significantly more LDGs compared to their treated counterparts. LDG nuclear morphology ranged from segmented to rounded, suggesting a heterogeneity within the group.
Conclusion: LDGs are a feature of the immunophenotype in some patients with MS and NMOSD
Dihydropyrimidine-thiones and clioquinol synergize to target beta-amyloid cellular pathologies through a metal-dependent mechanism
The lack of therapies for neurodegenerative diseases arises from our incomplete understanding of their underlying cellular toxicities and the limited number of predictive model systems. It is critical that we develop approaches to identify novel targets and lead compounds. Here, a phenotypic screen of yeast proteinopathy models identified dihydropyrimidine-thiones (DHPM-thiones) that selectively rescued the toxicity caused by β-amyloid (Aβ), the peptide implicated in Alzheimer’s disease. Rescue of Aβ toxicity by DHPM-thiones occurred through a metal-dependent mechanism of action. The bioactivity was distinct, however, from that of the 8-hydroxyquinoline clioquinol (CQ). These structurally dissimilar compounds strongly synergized at concentrations otherwise not competent to reduce toxicity. Cotreatment ameliorated Aβ toxicity by reducing Aβ levels and restoring functional vesicle trafficking. Notably, these low doses significantly reduced deleterious off-target effects caused by CQ on mitochondria at higher concentrations. Both single and combinatorial treatments also reduced death of neurons expressing Aβ in a nematode, indicating that DHPM-thiones target a conserved protective mechanism. Furthermore, this conserved activity suggests that expression of the Aβ peptide causes similar cellular pathologies from yeast to neurons. Our identification of a new cytoprotective scaffold that requires metal-binding underscores the critical role of metal phenomenology in mediating Aβ toxicity. Additionally, our findings demonstrate the valuable potential of synergistic compounds to enhance on-target activities, while mitigating deleterious off-target effects. The identification and prosecution of synergistic compounds could prove useful for developing AD therapeutics where combination therapies may be required to antagonize diverse pathologies.D.F.T was funded by NRSA Fellowship NIH 5F32NS061419. D.F.T. and S.L. were supported by WIBR funds in support of research on Regenerative Disease, the Picower/JPB Foundation, and the Edward N. and Della L. Thome Foundation. G.A.C. and S.L. were funded by a Howard Hughes Medical Institute (HHMI) Collaborative Innovation Award. L.E.B., R.T., and S.E.S. were funded by NIH GM086180, NIH GM067041, and NIH GM111625. (5F32NS061419 - NRSA Fellowship NIH; WIBR funds in support of research on Regenerative Disease; Picower/JPB Foundation; Edward N. and Della L. Thome Foundation; Howard Hughes Medical Institute (HHMI) Collaborative Innovation Award; GM086180 - NIH; NIH GM067041 - NIH; NIH GM111625 - NIH)https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5705239/Accepted manuscrip
Inference with interference between units in an fMRI experiment of motor inhibition
An experimental unit is an opportunity to randomly apply or withhold a
treatment. There is interference between units if the application of the
treatment to one unit may also affect other units. In cognitive neuroscience, a
common form of experiment presents a sequence of stimuli or requests for
cognitive activity at random to each experimental subject and measures
biological aspects of brain activity that follow these requests. Each subject
is then many experimental units, and interference between units within an
experimental subject is likely, in part because the stimuli follow one another
quickly and in part because human subjects learn or become experienced or
primed or bored as the experiment proceeds. We use a recent fMRI experiment
concerned with the inhibition of motor activity to illustrate and further
develop recently proposed methodology for inference in the presence of
interference. A simulation evaluates the power of competing procedures.Comment: Published by Journal of the American Statistical Association at
http://www.tandfonline.com/doi/full/10.1080/01621459.2012.655954 . R package
cin (Causal Inference for Neuroscience) implementing the proposed method is
freely available on CRAN at https://CRAN.R-project.org/package=ci
Ongoing Oxidative Stress Causes Subclinical Neuronal Dysfunction in the Recovery Phase of EAE
Most multiple sclerosis (MS) patients develop over time a secondary
progressive disease course, characterized histologically by axonal loss and
atrophy. In early phases of the disease, focal inflammatory demyelination
leads to functional impairment, but the mechanism of chronic progression in MS
is still under debate. Reactive oxygen species generated by invading and
resident central nervous system (CNS) macrophages have been implicated in
mediating demyelination and axonal damage, but demyelination and
neurodegeneration proceed even in the absence of obvious immune cell
infiltration, during clinical recovery in chronic MS. Here, we employ
intravital NAD(P)H fluorescence lifetime imaging to detect functional NADPH
oxidases (NOX1–4, DUOX1, 2) and, thus, to identify the cellular source of
oxidative stress in the CNS of mice affected by experimental autoimmune
encephalomyelitis (EAE) in the remission phase of the disease. This directly
affects neuronal function in vivo, as monitored by cellular calcium levels
using intravital FRET–FLIM, providing a possible mechanism of disease
progression in MS
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