FM/CW radar system

An FM/CW radar system is presented with improved noise discrimination in which the received signal is multiplied by a sample of the transmitted signal, and the product signal is employed to deflect a laser beam as a function of frequency. The position of the beam is thus indicative of a discrete frequency, and it is detected by the frequency encoded positions of an array of photodiodes. The outputs of the photodiodes are scanned, then threshold detected, and used to obtain the range and velocity of a target

Reaction of Certain Diploid and Tetraploid Alfalfas to Some Phytopathogens Including the Blackstem Disease

Alfalfa in South Dakota as in other parts of the United States and the world is adversely affected by a disease known as Blackstem. This disease is induced by one or more fungi or bacteria whose abundance depends as much on the high susceptibility of the current alfalfa varieties as on the weather. Differences in plant susceptibility to one of these microorganisms, Ascochyta imperfect, has already been shown to occur within and between alfalfa varieties or strains. Reitz working in Kansas obtained F1’s between highly resistant and highly susceptible plants that were intermediate in reaction to this fungus, and in a few crosses they noted a tendency of the resistant reactions of plants to be dominant over the susceptible. By inbreeding and hybridizing selected plants, they obtained a plant population with a higher resistance to this pathogen than the current varieties. Similar possibilities undoubtedly could exist for the other microorganisms including Blackstem, but no attempt has been made to date to determine this. Even for Ascochyta imperfecta, however, the preliminary work of Reitz, has never been extended or applied to the development of a commercial variety resistant to the disease. The purpose of the present study was to find out to what extent alfalfa plants differed in their reaction to the Blackstem disease induced by the various pathogens and to determine to what extent the reactions to these pathogens were heritable. If such plant differences could be shown to be heritable, an opportunity would thus be afforded to develop an alfalfa variety that resists the disease to a greater extent than any of those currently used. Field and greenhouse screening test accordingly, were conducted to measure plant reactions to three of the pathogens and the results obtained are presented herein

Real-time video correlator

Device provides two-dimensional correlation of video data. Operation is reliable, accurate, and predictable

The Impact of Frayer Models in a Mathematics Classroom

The purpose of this action research study was to explore the impact that Frayer Models have on students’ attitudes towards mathematics. I conducted a two-week unit on transformations, where students were introduced to a classroom focused on academic language, supplementing their learning with Frayer Models for homework and in-class assessments. I assessed their attitudes towards mathematics before and after the use of the Frayer Models, where I analyzed the effect that the Frayer Models had on the students and their use of academic language. It was evident that most of the students’ found the focus on academic language beneficial to their learning, thus positively affecting their attitude and confidence level with mathematics as a whole. Although some students did not find an appeal for Frayer Models as much as others, the models still helped students in the learning of the terms and developing a better understanding on mathematics being a reflective process involving reasoning and sense-making

Mass Loss History of Evolved Stars

We provide high-resolution maps of the circumstellar dust shells of several dozen Asymptotic Giant Branch (AGB) stars using data from the Spitzer space telescope Multiband Imaging Photometer (MIPS) imaged at 70µm. AGB stars are the major contributors of chemical elements such as carbon, oxygen and silicon, which are essential to the existence of life in the universe, through mass loss processes that take place at the surface of the star. We probe the spatial distribution of cold (~40 K) dust grains in order to trace the history of mass loss from the observed radial density variation in these shells. Our images illustrate that different morphologies may evolve because AGB stars can already interact with the interstellar medium (ISM) that surrounds them even at these early stages of the AGB mass loss history. Relative motion of the star as well as the ISM with respect to the local environment may be of particular importance for shell structure evolution

Spectropolarimetry of epsilon Aurigae: Probing Stellar and Disk Atmospheres

The bright eclipsing binary system epsilon Aurigae offers a unique opportunity to uncover physical mechanisms contributing to disk formation and evolution and to explore the relationship between photospheric anisotropies, stellar pulsation and mass loss. This research contributes to our understanding of stellar evolution in the context of binary stars. The research also offers the opportunity to investigate disk formation and evolution significant to our understanding of protoplanetary disks now seen in many star systems. Lastly, the project considers radiative transfer of polarized light that contributes to diverse fields such as atmospheric studies of exoplanets. My objective is to understand the evolutionary status of the eclipsing disk in the epsilon Aurigae system by exploring the distribution of gas and characteristics of dust grains in the disk. I evaluated spectral features and linear polarization in ESPaDOnS out-of-eclipse spectra in order to characterize line polarization observed in the system. It is important to understand the out-of-eclipse behavior in order to correctly differentiate signals seen in ESPaDOnS spectra taken during the most recent (2009--2011) eclipse. This thesis work tested the hypothesis that the F0 star in the system shows intrinsic broadband polarization and that the percent linear polarization (%p) is related to the brightness of the variable F0 star observed out--of--eclipse. Uncovering the position angle of intrinsic linear polarization also tested whether dust grains in the disk are small (\u3c 1 micron) or large (\u3e10 micron). I evaluated spectral features and line polarization of select disk lines before, during and after eclipse in order to better resolve the distribution of gas in the disk. Significant (\u3e4 sigma) linear polarization peaks are associated with spectral absorption features and the scattering geometry is revealed by an analysis of the dominant polarization position angles. I characterized the contribution of interstellar polarization using archived data from the HPOL polarimeter and from published broadband filter data and subtracted the interstellar component from broadband out--of--eclipse and in--eclipse observations to characterize the intrinsic continuum polarization of the system. Results of these efforts are itemized below. First, linear polarization is persistent in out--of--eclipse observations, appears strongest in the core of each associated spectral line and is variable in time and strength. The polarization observed out--of--eclipse likely arises from an equatorial density enhancement in the gas in the outer layers of the F0 star. Second, disk rotation signatures appear in eclipse polarization spectra in both low energy (Ell \u3c 3eV) and high energy (Ell \u3e3eV) atomic transitions just after mid--eclipse even when additional absorption does not appear to be present in the line. Linear polarization (%p) is bi-lobed and Stokes U is anti-symmetric through the line at these times. These polarimetric signatures are consistent with line polarization in models of optically thick rotating disks. Third, an increase in line polarization precedes an increase in continuum polarization near eclipse 3rd contact. This is due to a density enhancement in the disk located on the side of the disk illuminated by the F0 star but offset from the direct line in the direction of disk rotation. I propose that scattering angles imposed by the system geometry are responsible for the phenomenon. Line polarization is stronger at egress than ingress supporting a model in which a temperature gradient is present in the disk, and the back side of the disk extends above the dusty opaque layer after mid-eclipse. Finally, intrinsic continuum polarization observed out-of-eclipse (OOE) is sometimes wavelength-dependent. Changes to %p are not correlated with changes in F0 star brightness. I uncovered the underlying intrinsic polarization in published eclipse data to find an intrinsic linear polarization position angle of 90 degrees in the stellar/disk reference frame during mid--eclipse phases. Polarization during eclipse primarily arises from forward--scattering at large dust grains or from multiple scattering from optically thick dusty material. Optically thin scattering from small grains would yield position angles closer to 0 degrees in the stellar/disk reference frame. The presence of large dust grains suggests that the disk is an evolved debris disk rather than a young proto-planetary disk and that the F0 star in the system is an evolved star

Un nuevo género para Habrothrix angustidens y Akodon serrensis (RODENTIA, CRICETIDAE): de nuevo palentología y neontología se encuentran en el legado de Lund

We describe a new genus of sigmodontine rodent to allocate a fossil species from Lagoa Santa cave deposits, Habrothrix angustidens Winge, and a living species from southeastern Atlantic Forest described at the start of the past century, Akodon serrensis Thos. Tentatively, both forms are considered as synonyms pending a detailed revision of the genus. The new genus belongs to the Akodon Division of the diverse tribe Akodontini where, based on molecular evidence, it is sister to Thaptomys, another forest-dwelling akodontine. The new genus is characterized by a unique combination of morphological traits including tail shorter than head-and-body; manual and pedal digits with short claws; skull robust with pointed rostrum, broad and somewhat flat interorbital region with frontal borders divergent posteriorly, and enlarged braincase without crests; large incisive foramina with expanded palatal process of premaxillary; broad mesopterygoid fossa with anterior margin rounded; alisphenoid strut present; carotid arterial circulation pattern primitive; molars noticeably large in relation to the skull and moderately hypsodont; main molar cusps arranged in opposite pairs; first upper molar without anteromedian flexus; length of third lower molar subequal to those of second lower molar; mandible without distinct capsular process; gall bladder present; stomach unilocular and hemiglandular; 2n = 46 (FN = 46). The new genus is an Atlantic Forest endemic, indicating that the diversity of Akodontini has been overlooked outside of the Andes.Describimos un nuevo género de roedor sigmodontino para ubicar una especie fósil de los depósitos de Lagoa Santa, Habrothrix angustidens Winge y una especie viviente del sudeste de la Selva Atlántica descripta en los comienzos de la centuria pasada, Akodon serrensis Thos. Tentativamente, ambas formas son consideradas sinónimos a la espera de una revisión detallada de la diversidad del género. El nuevo género pertenece a la División Akodon de la diversa tribu Akodontini donde, sobre la base de evidencia molecular, resulta hermano de Thaptomys, otro akodontino especialista de selva. El nuevo género se caracteriza por una combinación única de rasgos morfológicos incluyendo una cola más corta que el largo cabeza-cuerpo, garras de los dedos de la mano y el pie cortas, cráneo robusto con rostro puntiagudo, región interorbitaria ancha y algo chata con los bordes frontales divergentes hacia atrás y caja craneana agrandada y sin crestas, forámenes incisivos expandidos con proceso palatal del premaxilar bien desarrollado, fosa mesopterigoidea ancha con el borde anterior redondeado, barra alisfenoidea presente, patrón de circulación carotídea primitivo, molares notablemente grandes en relación a las proporciones del cráneo y moderadamente hipsodontes, principales cúspides de los molares dispuestas en pares opuestos, primer molar superior carente de flexo anteromediano, largo del tercer molar inferior subigual al del segundo molar inferior, mandíbula sin proyección capsular evidente, vesícula biliar presente, estómago unilocular-hemiglandular, 2n = 46 (FN = 46). El nuevo género es endémico de la Selva Atlántica indicando una insospechada diversidad de los Akodontini en regiones extraandinas.Fil: Pardiñas, Ulises Francisco J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; ArgentinaFil: Geise, Lena. Universidade do Estado do Rio de Janeiro, Rua São Francisco Xavier; BrasilFil: Ventura, Karen. Universidade Federal de Itajubá; BrasilFil: Lessa, Gissele. Universidade Federal de Viçosa; Brasi