203 research outputs found
Engagement of the T-cell receptor during positive selection in the thymus down-regulates RAG-1 expression.
ID, GPS Tracking, 24/7 Tag Link for CubeSats and Constellations: Flight Results
The tiny 40-gram EyeStar-Tag processor, GPS, and radio link will ID its satellite with GPS and critical status data within a minute after turn-on. The autonomous low power EyeStar Tag GPS (20mW for 3D lock) is now at TRL-9 based on the successful release and operation of the Spaceflight Inc. ring on the 1/24/2021 rideshare launch. The orbit (530 km polar) was projected using GPS seven element arrays to generate, on the fly, the future ephemeris predictions while monitoring critical fight systems. The Tag continues to transmit over the Globalstar network of satellites and ground stations the GPS elements and status with low latency of seconds, even if the primary satellite fails or stops. Whether dead or alive, orbital elements and TLEs for debris tracking, attitude, and ID are available to the 18th Squadron. AFWERXâs SBIR investment helped fast track the Black Box and Tag systems. Key enablers and new architecture are flight referenced for 30 ThinSat constellation launched in February 2021 NG-15.
With the Globalstar constellation NSL can monitor a satellite 24/7 anywhere in LEO orbits with data available anytime, without the need for expensive ground stations. With a 100% success in orbit using the NSL EyeStar processor and Globalstar comm systems (110+ radios in space with several tumbling) can contribute to the commercial, educational, and research small satellite market that is rapidly growing. The EyeStar radio is ideal for the next step to advance many NASA, DOD, commercial, and STEM satellites now that appropriate FCC, NTIA, and ITU licenses have all been approved.
The aircraft Black Box is well known and is essential for crash diagnostics after the fact, but in addition, the satellite Black Box and processor will operate in Telemetry Tracking and Command (TT&C) mode during the whole mission and will continue TT&C in orbit after a completed or failed mission. The Black Box transmits vital data, health and safety information, GPS, and summary data while in orbit for 24/7 coverage. With its included solar arrays, the Black Box would operate for many years after the primary satellite fails so that essential data and tracking is continuous, and altitude known. If the satellite reawakens after some long failure, the Black Box reports the new status, and the satellite may be reactivated. NSL customers have experienced this wake-up mode after a year on one of our Black Box/EyeStar communication processors after an unexpected two-month âdeadâ phase and wake. The âdeadâ satellite was reactivated
White-tailed Deer Browsing and Rubbing Preferences for Trees and Shrubs That Produce Nontimber Forest Products
Nontimber forest products (food, herbal medicinals, and woody floral and handicraft products) produced in forest, agroforestry, and horticultural systems can be important sources of income to landowners. White-tailed deer (Odocoileus virginianus) can reduce the quality, quantity, and profitability of forest products by browsing twigs and rubbing stems, resulting in direct and indirect losses to production enterprises. We evaluated deer damage (frequency and intensity of browsing and rubbing) sustained by 26 species of trees and shrubs, the relationships among morphological features of trees and shrubs to damage levels, and the economic impacts of deer damage on the production of nontimber forest products. Levels of browsing were high (frequency \u3e93% and intensity \u3e50%) in most species of trees and shrubs, with the highest intensity (\u3e60%) occurring in chinese chestnut (Castanea mollisima) and dogwood (Cornus spp.), and the lowest (Ginkgo biloba), curly willow (Salix matsudana), âScarlet Curlsâ curly willow, smooth sumac (Rhus glabra), and pussy willow (Salix caprea). Species of trees or shrubs with one or a few stout stems unprotected by dense branching [e.g., american elderberry (Sambucus canadensis), smooth sumac, and curly willow] sustained the most damage by rubbing. Trees and shrubs with many small diameter stems or with dense tangled branching [e.g. redozier dogwood (Cornus sericea), forsythia (Forsythia suspensa), âFlameâ willow (Salix alba), and âStreamcoâ basket willow (Salix purpurea)] were damaged the least by rubbing. Annual economic costs of deer damage to producers of nontimber forest products can range from 1595/acre for curly willow
Moving Five-Branes in Low-Energy Heterotic M-Theory
We construct cosmological solutions of four-dimensional effective heterotic
M-theory with a moving five-brane and evolving dilaton and T modulus. It is
shown that the five-brane generates a transition between two asymptotic
rolling-radii solutions. Moreover, the five-brane motion always drives the
solutions towards strong coupling asymptotically. We present an explicit
example of a negative-time branch solution which ends in a brane collision
accompanied by a small-instanton transition. The five-dimensional origin of
some of our solutions is also discussed.Comment: 16 pages, Latex, 3 eps figure
A solution of the coincidence problem based on the recent galactic core black hole mass density increase
A mechanism capable to provide a natural solution to two major cosmological
problems, i.e. the cosmic acceleration and the coincidence problem, is
proposed. A specific brane-bulk energy exchange mechanism produces a total dark
pressure, arising when adding all normal to the brane negative pressures in the
interior of galactic core black holes. This astrophysically produced negative
dark pressure explains cosmic acceleration and why the dark energy today is of
the same order to the matter density for a wide range of the involved
parameters. An exciting result of the analysis is that the recent rise of the
galactic core black hole mass density causes the recent passage from cosmic
deceleration to acceleration. Finally, it is worth mentioning that this work
corrects a wide spread fallacy among brane cosmologists, i.e. that escaping
gravitons result to positive dark pressure.Comment: 14 pages, 3 figure
Phenomenology of heterotic M-theory with five-branes
We analyze some phenomenological implications of heterotic M-theory with
five-branes. Recent results for the effective 4-dimensional action are used to
perform a systematic analysis of the parameter space, finding the restrictions
that result from requiring the volume of the Calabi-Yau to remain positive.
Then the different scales of the theory, namely, the 11-dimensional Planck
mass, the compactification scale and the orbifold scale, are evaluated.
The expressions for the soft supersymmetry-breaking terms are computed and
discussed in detail for the whole parameter space. With this information we
study the theoretical predictions for the supersymmetric contribution to the
muon anomalous magnetic moment, using the recent experimental result as a
constraint on the parameter space. We finally analyze the neutralino as a dark
matter candidate in this construction. In particular, the neutralino-nucleon
cross-section is computed and compared with the sensitivities explored by
present dark matter detectors.Comment: Final version to appear in Phys. Rev. D. Some comments and references
added. 37 pages, 19 figure
Computer modeling of diabetes and Its transparency: a report on the Eighth Mount Hood Challenge
Objectives
The Eighth Mount Hood Challenge (held in St. Gallen, Switzerland, in September 2016) evaluated the transparency of model input documentation from two published health economics studies and developed guidelines for improving transparency in the reporting of input data underlying model-based economic analyses in diabetes.
Methods
Participating modeling groups were asked to reproduce the results of two published studies using the input data described in those articles. Gaps in input data were filled with assumptions reported by the modeling groups. Goodness of fit between the results reported in the target studies and the groupsâ replicated outputs was evaluated using the slope of linear regression line and the coefficient of determination (R2). After a general discussion of the results, a diabetes-specific checklist for the transparency of model input was developed.
Results
Seven groups participated in the transparency challenge. The reporting of key model input parameters in the two studies, including the baseline characteristics of simulated patients, treatment effect and treatment intensification threshold assumptions, treatment effect evolution, prediction of complications and costs data, was inadequately transparent (and often missing altogether). Not surprisingly, goodness of fit was better for the study that reported its input data with more transparency. To improve the transparency in diabetes modeling, the Diabetes Modeling Input Checklist listing the minimal input data required for reproducibility in most diabetes modeling applications was developed.
Conclusions
Transparency of diabetes model inputs is important to the reproducibility and credibility of simulation results. In the Eighth Mount Hood Challenge, the Diabetes Modeling Input Checklist was developed with the goal of improving the transparency of input data reporting and reproducibility of diabetes simulation model results
TNF-α Signals Through PKCζ/NF-ÎșB to Alter the Tight Junction Complex and Increase Retinal Endothelial Cell Permeability
Radion Dynamics and Electroweak Physics
The dynamics of a stabilized radion in the Randall-Sundrum model (RS) with
two branes is investigated, and the effects of the radion on electroweak
precision observables are evaluated. The radius is assumed to be stabilized
using a bulk scalar field as suggested by Goldberger and Wise. First the mass
and the wavefunction of the radion is determined including the backreaction of
the bulk stabilization field on the metric, giving a typical radion mass of
order the weak scale. This is demonstrated by a perturbative computation of the
radion wavefunction. A consequence of the background configuration for the
scalar field is that after including the backreaction the Kaluza-Klein (KK)
states of the bulk scalars couple directly to the Standard Model fields on the
TeV brane. Some cosmological implications are discussed, and in particular it
is found that the shift in the radion at late times is in agreement with the
four-dimensional effective theory result. The effect of the radion on the
oblique parameters is evaluated using an effective theory approach. In the
absence of a curvature-scalar Higgs mixing operator, these corrections are
small and give a negative contribution to S. In the presence of such a mixing
operator, however, the corrections can be sizable due to the modified Higgs and
radion couplings.Comment: 42 pages, LaTeX, 14 figures; v2: minor changes and references added.
To appear in PR
- âŠ