Phase and amplitude scintillations of microwave signals over an elevated atmospheric path

Phase and amplitude scintillations of microwave signals over elevated atmospheric path for obtaining atmospheric density profile

Data Analysis of the Floating Potential Measurement Unit aboard the International Space Station

We present data from the Floating Potential Measurement Unit (FPMU), that is deployed on the starboard (S1) truss of the International Space Station. The FPMU is a suite of instruments capable of redundant measurements of various plasma parameters. The instrument suite consists of: a Floating Potential Probe, a Wide-sweeping spherical Langmuir probe, a Narrow-sweeping cylindrical Langmuir Probe, and a Plasma Impedance Probe. This paper gives a brief overview of the instrumentation and the received data quality, and then presents the algorithm used to reduce I-V curves to plasma parameters. Several hours of data is presented from August 5th, 2006 and March 3rd, 2007. The FPMU derived plasma density and temperatures are compared with the International Reference Ionosphere (IRI) and USU-Global Assimilation of Ionospheric Measurement (USU-GAIM) models. Our results show that the derived in-situ density matches the USU-GAIM model better than the IRI, and the derived in-situ temperatures are comparable to the average temperatures given by the IRI

Delayed Photoionization Feedback in a Super Star Cluster in SBS0335-052E

SBS0335-052 is a well studied Blue Compact Dwarf galaxy with one of the lowest metallicities of any known galaxy. It also contains 6 previously identified Super Star Clusters. We combine archival HST NICMOS images in the Pa alpha line and the 1.6 micron continuum of the eastern component, SBS0335-052E, with other space and ground based data to perform a multi-wavelength analysis of the super star clusters. We concentrate on the southern most clusters, designated S1 and S2, which appear to be the youngest clusters and are the strongest emitters of Pa alpha, radio, and x-ray flux. Our analysis leads to a possible model for S1 and perhaps S2 as a cluster of very young, massive stars with strong stellar winds. The wind density can be high enough to absorb the majority of ionizing photons within less than 1000 AU of the stars, creating very compact HII regions that emit optically thick radiation at radio wavelengths. These winds would then effectively quench the photoionizing flux very close to the stars. This can delay the onset of negative feedback by photoionization and photodissociation on star formation in the clusters. This is significant since SBS0335-052E resembles the conditions that were probably common for high redshift star formation in galaxies near the epoch of reionization.Comment: Accepted for publication in the Astrophysical Journa

Coral mucus rapidly induces chemokinesis and genome-wide transcriptional shifts toward early pathogenesis in a bacterial coral pathogen.

Elevated seawater temperatures have contributed to the rise of coral disease mediated by bacterial pathogens, such as the globally distributed Vibrio coralliilyticus, which utilizes coral mucus as a chemical cue to locate stressed corals. However, the physiological events in the pathogens that follow their entry into the coral host environment remain unknown. Here, we present simultaneous measurements of the behavioral and transcriptional responses of V. coralliilyticus BAA-450 incubated in coral mucus. Video microscopy revealed a strong and rapid chemokinetic behavioral response by the pathogen, characterized by a two-fold increase in average swimming speed within 6 min of coral mucus exposure. RNA sequencing showed that this bacterial behavior was accompanied by an equally rapid differential expression of 53% of the genes in the V. coralliilyticus genome. Specifically, transcript abundance 10 min after mucus exposure showed upregulation of genes involved in quorum sensing, biofilm formation, and nutrient metabolism, and downregulation of flagella synthesis and chemotaxis genes. After 60 min, we observed upregulation of genes associated with virulence, including zinc metalloproteases responsible for causing coral tissue damage and algal symbiont photoinactivation, and secretion systems that may export toxins. Together, our results suggest that V. coralliilyticus employs a suite of behavioral and transcriptional responses to rapidly shift into a distinct infection mode within minutes of exposure to the coral microenvironment

Test Bed for Quantitative NDE

The ARPA/AFML Interdisciplinary Program for Quantitative Flaw Definition has demonstrated a number of new techniques for quantitatively sizing flaws, as are reported elsewhere in these proceedings. This paper describes a test bed program to assemble and demonstrate these techniques in a single integrated measurement system that will extend them from the idealized geometries that have been considered thus far to geometries that are a better approximation to those that are found in real parts. Included are discussions of the conceptual design of the system, the detailed design and construction of specific modules, and preliminary experimental results. The basic system consists of a Data General Eclipse S/200 minicomputer, a multi-axis microprocessor controller, a Biomation A/D converter, an immersion tank, and a contour following system with six degrees of freedom. A detailed description of the operation of the various components of the system will be given. Included are discussions of the conceptual design of the system, detailed design and construction of specific modules, and preliminary experimental results

High Energy Gamma-Ray Emission From Blazars: EGRET Observations

We will present a summary of the observations of blazars by the Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory (CGRO). EGRET has detected high energy gamma-ray emission at energies greater than 100 MeV from more that 50 blazars. These sources show inferred isotropic luminosities as large as $3\times 10^{49}$ ergs s$^{-1}$. One of the most remarkable characteristics of the EGRET observations is that the gamma-ray luminosity often dominates the bolometric power of the blazar. A few of the blazars are seen to exhibit variability on very short time-scales of one day or less. The combination of high luminosities and time variations seen in the gamma-ray data indicate that gamma-rays are an important component of the relativistic jet thought to characterize blazars. Currently most models for blazars involve a beaming scenario. In leptonic models, where electrons are the primary accelerated particles, gamma-ray emission is believed to be due to inverse Compton scattering of low energy photons, although opinions differ as to the source of the soft photons. Hardronic models involve secondary production or photomeson production followed by pair cascades, and predict associated neutrino production.Comment: 16 pages, 7 figures, style files included. Invited review paper in "Observational Evidence for Black Holes in the Universe," 1999, ed. S. K. Chakrabarti (Dordrecht: Kluwer), 215-23

Trace-element composition of Chicxulub crater melt rock, K/T tektites and Yucatan basement

The Cretaceous/Tertiary (K/T) boundary Chicxulub impact is the best preserved large impact in the geologic record. The Chicxulub crater has been buried with no apparent erosion of its intracrater deposits, and its ejecta blanket is known and is well preserved at hundreds of localities globally. Although most of the molten material ejected from the crater has been largely altered, a few localities still preserve tektite glass. Availability of intra- and extracrater impact products as well as plausible matches to the targeted rocks allows the comparison of compositions of the different classes of impact products to those of the impacted lithologies. Determination of trace-element compositions of the K/T tektites, Chicxulub melt rock, and the targeted Yucatan silicate basement and carbonate/evaporite lithologies have been made using instrumental neutron activation analysis (INAA) and inductively coupled plasma mass spectrometry (ICP-MS). Some sample splits were studied with both techniques to ensure that inter-laboratory variation was not significant or could be corrected. The concentration of a few major and minor elements was also checked against microprobe results. Radiochemical neutron activation analysis (RNAA) was used to determine Ir abundances in some samples

Mendelian Randomization using Public Data from Genetic Consortia.

Mendelian randomization (MR) is a technique that seeks to establish causation between an exposure and an outcome using observational data. It is an instrumental variable analysis in which genetic variants are used as the instruments. Many consortia have meta-analysed genome-wide associations between variants and specific traits and made their results publicly available. Using such data, it is possible to derive genetic risk scores for one trait and to deduce the association of that same risk score with a second trait. The properties of this approach are investigated by simulation and by evaluating the potentially causal effect of birth weight on adult glucose level. In such analyses, it is important to decide whether one is interested in the risk score based on a set of estimated regression coefficients or the score based on the true underlying coefficients. MR is primarily concerned with the latter. Methods designed for the former question will under-estimate the variance if used for MR. This variance can be corrected but it needs to be done with care to avoid introducing bias. MR based on public data sources is useful and easy to perform, but care must be taken to avoid false precision or bias

Recent Cases

If the instant case, rather than Northway, is to become the accepted rule in the area of discounting, consumers and state lenders will be protected while the national bank-lenders will be burdened only slightly, if at all. National banks located in states that permit state lenders to discount loans at the maximum rate, with-out regard to the actual yield, will not be affected. National banks located in states that permit state lenders to discount only to the extent that the actual yield is within the statutory maximum will need to change their practices merely by charging the statutory rate only when it becomes due, or by charging a lower rate in advance that yields an effective rate not in excess of the maximum. Furthermore, the impact of the instant decision on national banks will be practically limited to consumer loans, because of the usual exemption of corporations from usury laws and of section 85\u27s higher alternative rate for business or agricultural loans. This limited restriction on the national banks will be justified by its beneficent effect on the borrower and on the competing state lenders, who have always been subject to the state restrictions. Linda A. Bunsey ======================= With the instant decision, federal defamation law has advanced within the space of ten years from no constitutional privilege, even for the press in defending against a public person, to the realized prospect of a constitutional privilege so sweeping that it prevents recovery of an element of damages by a public person who has been defamed by an individual. Specifically, the instant court\u27s holding completes a four-part scheme for liability and damages in defamation actions: under Supreme Court decisions, a private figure must prove negligence to receive compensatory damages and actual malice to receive punitive damages, and a public figure must prove actual malice to recover compensatory damages; under the instant decision, a public figure is almost totally precluded from recovering punitive damages. As the Sullivan Court in large measure adopted the minority position concerning fair comment and liability, so too the Maheu court in large measure adopted the minority position concerning punitive damages. Nevertheless, the instant decision was solidly based: the court fully considered the Supreme Court\u27s prior concerns with encouraging debate and discouraging self-censorship, shielding reputation and privacy, and, most importantly, scrutinizing the need for punitive damages. David M. Thompson ============================ In rejecting the State\u27s reliance upon the stated rule of the Brady trilogy and Tollett, the instant Court noted the suggestion originally made in a McMann footnote that an exception might exist if the applicable state law permitted appeal from adverse pretrial rulings despite a subsequent guilty plea. Under New York procedure, a defendant who chooses to plead guilty does not deliberately by-pass state appellate review of certain constitutional claims, and the State acquires no legitimate expectation of finality in the ensuing conviction. As to these constitutional claims, the plea does not constitute a break in the chain, but operates merely as a procedural device to secure review of the adverse pretrial ruling without the necessity of a time-consuming and expensive trial. The Court held that because the respondent\u27s guilty plea was entered in reliance upon a guarantee of the availability of further appellate review of his constitutional claims, it was essentially different from guilty pleas entered in other states that result in an absolute conviction and a waiver of all further state review. Charles K. Campbell, Jr. ======================================== In determining whether the challenged statute met the procedural requirements of the fourteenth amendment, the instant Court looked to the statutory safeguards protecting the debtor\u27s property interest in the absence of prior notice and hearing. Comparing the instant statute to the Fuentes statutes, the Court asserted that the same constitutional infirmities were present. Each statute allowed the seizure of property without prior notice and opportunity for a hearing by the issuance of a writ by a court clerk after the filing of an affidavit containing conclusory allegations. The instant Court restated its belief set forth in Sniadach and Fuentes that even a temporary deprivation of property does not put the seizure beyond scrutiny under due process requirements. The Court then asserted that the Georgia statute had none of the saving characteristics of the Louisiana sequestration statute upheld in Mitchell. According to the Court, the Mitchell statute survived challenge because of the presence of safeguards which imposed judicial control over the process of issuance of the writ; required the creditor\u27s affidavit to contain factual allegations; and provided for an immediate post-seizure hearing at which the debtor could seek dissolution of the writ. Keith B. Simmons ============================== The instant court rejected arguments based mainly on the vague wording of the statute and relied on two basic policies-(1)to compel pro rata distributions of unneeded funds that will be taxable to shareholders and (2) to avoid constructions that lead to inconsistent results in similar fact situations. Also, the court seemed to contemplate two theories of liability available to the Commissioner-first, that the corporation was availed of by permitting funds not used in the redemption to remain accumulated, and secondly, that the corporation was availed of through the redemption itself. The arguments based on the equivalency of the phrases to accumulate and to remain accumulated , the purpose of Congress to reach any corporation with an undue accumulation, and the relevance of past accumulations, plus the remand for determination of whether an unreasonable accumulation actually occurred, relate to the first theory. Other arguments used by the court relate more to the second theory-the repeated idea that preferential distribution of unneeded funds is not a congressionally approved method of abating the penalty tax with respect to those funds, the mention of corporations formed for the proscribed purpose that may be liable without regard to actual accumulation, and especially the concluding statement that the judgment concerning 1967 made liability in 1968 apparent. Thomas C. Hundle