Terrain relative localization for lunar entry, descent, and landing

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2007.Includes bibliographical references (p. 297-298).As exploration of the solar system continues, the need for the capability to land a spacecraft very accurately on a planetary body has become apparent. Due to limitations on the achievable accuracy of inertial navigation systems over long distances, relative navigation techniques are better suited to fill this need. Chief among these techniques is terrain relative navigation. Terrain relative navigation uses the surface features of a planetary body and an onboard map of the planetary surface to determine the spacecraft's position and update the inertial navigation system. One of the tasks of terrain relative navigation is terrain relative localization, which entails matching a sensor image of the planetary surface to the stored map of the surface. This correlation allows a position match to be determined, which is used to update the spacecraft's inertial navigation system. This thesis focuses upon two terrain relative localization techniques and their applicability to lunar entry, descent, and landing. These localization techniques are terrain contour matching (TERCOM) and a crater matching routine. Both methods are tested using simulation environments that mimic expected conditions in lunar navigation. The ability of each algorithm to generate a position match with no noise is evaluated, as well as the performance of each algorithm under various sensor noise conditions. The terrain contour matching algorithm generates a high level of error in the position match and is found to be unsuitable for lunar terrain relative navigation. The crater matching routine performs quite well, with low processing speeds, moderate memory requirements, and a high level of position match fidelity under moderate noise conditions. The crater matching routine is recommended for continued work and potential application to lunar navigation during entry, descent, and landing.by Matthew J. Hale.S.M

Transcendental Tijuanense telecommunications bridge to everywhere

Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 2009.Includes bibliographical references (p. 56-57).Send My Love to Tijuana I Tijuana Sends Her Love replaces an existing pedestrian bridge that connects two vibrant neighborhoods in Tijuana, Mexico. The bridge is strategically situated to integrate itself into the city's urban fabric, while maintaining visibility from the United States Border and the San Ysidro Border crossing, the most heavily trafficked border crossing in the world. There, passage is tightly controlled, extending wait-times to unbearable lengths for even those permitted to cross legally. Nearby, my project provides an alternative portal that is universally accessible to those who wish to reconnect with their loved ones by way of another, virtual means: free videoconferencing within dedicated spaces. These spaces range in scale, beginning with the precedent of the phone booth for private, intimate conversations and ending with large-scale public projection zones for families. In either case, families and loved ones are reconnected on opposite sides of the border in a communion whose significance is witnessed by the monumental scale and form of the architectural composition. Not only is the building's form significant, its details also contribute to its monumental character. While the fagade facing the United States is a severe 900 foot-long, 40 foot-high, rectangular, corrugated steel, reflection of the existing border "fence", its symbolic severity is subtly subverted by an array of millions of end lit fiber optic cables. These cables are translucent hairs that blow in the breeze and that channel in from the fagade through the building's folded steel structure, and out into rooms, out beside walkways, and out through ceilings.(cont.) When light activates one end of the optical cable, it illuminates on the opposite end as well. Therefore, the cable channeling system allows for daylight to penetrate the interior spaces, whereas at night, the fagade is illuminated by the internally lit building. The illumination on the fagade is an eery, abstract depiction of the activities inside, as shadows from pedestrians deactivate the cables they pass, and the family-conferencing projections activate cables that portray content on the fagade. Finally, individual lights within the personal telecommunications rooms, when in use, can also be mapped to their own zones. Thus, form and fiber optics enhance the symbolic value of the bridge, which anyway represents the human desire to connect, and directly opposes the ever impassible border wall, which is an embodiment of military might and the distinctly human desire to separate. This thesis project was inspired by my personal experiences with the family members left behind in Central and South America by their dearest relatives-children, husbands, wives-who journeyed illegally to United States in order to garner a financial foothold to support their loved ones back home.by Mary E. Hale.M.Arch

Delay Equations and Radiation Damping

Starting from delay equations that model field retardation effects, we study the origin of runaway modes that appear in the solutions of the classical equations of motion involving the radiation reaction force. When retardation effects are small, we argue that the physically significant solutions belong to the so-called slow manifold of the system and we identify this invariant manifold with the attractor in the state space of the delay equation. We demonstrate via an example that when retardation effects are no longer small, the motion could exhibit bifurcation phenomena that are not contained in the local equations of motion.Comment: 15 pages, 1 figure, a paragraph added on page 5; 3 references adde

The effect of a diet with fructan-rich chicory roots on intestinal helminths and microbiota with special focus on Bifidobacteria and Campylobacter in piglets around weaning

The restrictions on the use of antibiotic and anthelmintic treatments in organic pig farming necessitate alternative non-medical control strategies. Therefore, the antibiotic and parasite-reducing effect of a fructan-rich (prebiotic) diet of dried chicory was investigated in free-ranging piglets. Approximately half of 67 piglets from 9 litters were experimentally infected with Ascaris suum and Trichuris suis in the suckling period (1 to 7 weeks of age) and 58 of the piglets were challenged daily with E. coli O138:F8 for 9 days after weaning to induce weaning diarrhoea. The litters were fed either chicory (30% DM) or a control diet. The effect of chicory on intestinal helminths, intestinal microbiota, especially Bifidobacteria and Campylobacter spp., and E. coli post-weaning diarrhoea was assessed. The weight gain of the piglets was not impaired significantly by chicory. The intestinal A. suum worm burden was reduced by 64% (P=0.034) in the chicory-fed piglets, whereas these same piglets had 63% more T. suis worms (P=0.016). Feeding with chicory elicited no changes among the main bacterial groups in ileum according to terminal restriction fragment length polymorphism (T-RFLP) analysis. However, the terminal-restriction fragment (T-RF) 208 bp, which may belong to Lachnospiraceae, was stimulated by the chicory feed (P=0.03), and T-RF 370 bp that matches Enterobacter belonging to the Enterobacteria was reduced (P=0.004). Additionally, chicory increased the level of Bifidobacteria (P=0.001) and the faecal Campylobacter excretion level was transitorily reduced in chicory-fed piglets at 7 weeks of age (P=0.029). Unfortunately, it was not possible to assess the effect of chicory on post-weaning diarrhoea as it did not develop. In conclusion, feeding piglets chicory around the time of weaning caused complex changes of the microbiota and parasite communities within the intestinal tract, and feeding piglets chicory may therefore serve as an animal-friendly strategy to control pathogens

On Pole Assignment and Stabilizability of Neutral Type Systems

In this note we present a systematic approach to the stabilizability problem of linear infinite-dimensional dynamical systems whose infinitesimal generator has an infinite number of instable eigenvalues. We are interested in strong non-exponential stabilizability by a linear feed-back control. The study is based on our recent results on the Riesz basis property and a careful selection of the control laws which preserve this property. The investigation may be applied to wave equations and neutral type delay equations

Galloylated proanthocyanidins from shea (Vitellaria paradoxa) meal have potent anthelmintic activity against Ascaris suum

Proanthocyanidins (PA) from shea (Vitellaria paradoxa) meal were investigated by thiolytic degradation with benzyl mercaptan and the reaction products were analysed by high performance liquid chromatography–mass spectrometry. These PA were galloylated (≈40%), contained only B-type linkages and had a high proportion of prodelphinidins (>70%). The mean degree of polymerisation was 8 (i.e. average molecular size was 2384 Da) and epigallocatechin gallate (EGCg) was the major flavan-3-ol subunit in PA. Shea meal also proved to be a potentially valuable source for extracting free flavan-3-ol-O-gallates, especially EGCg (575 mg/kg meal), which is known for its health and anti-parasitic benefits. Proanthocyanidins were isolated and tested for bioactivity against Ascaris suum, which is an important parasite of pigs. Migration and motility tests revealed that these PA have potent activity against this parasitic nematode

An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types

An Examination of Chimpanzee Use in Human Cancer Research

Advocates of chimpanzee research claim the genetic similarity of humans and chimpanzees make them an indispensable research tool to combat human diseases. Given that cancer is a leading cause of human death worldwide, one might expect that if chimpanzees were needed for, or were productive in, cancer research, then they would have been widely used. This comprehensive literature analysis reveals that chimpanzees have scarcely been used in any form of cancer research, and that chimpanzee tumours are extremely rare and biologically different from human cancers. Often, chimpanzee citations described peripheral use of chimpanzee cells and genetic material in predominantly human genomic studies. Papers describing potential new cancer therapies noted significant concerns regarding the chimpanzee model. Other studies described interventions that have not been pursued clinically. Finally, available evidence indicates that chimpanzees are not essential in the development of therapeutic monoclonal antibodies. It would therefore be unscientific to claim that chimpanzees are vital to cancer research. On the contrary, it is reasonable to conclude that cancer research would not suffer, if the use of chimpanzees for this purpose were prohibited in the US. Genetic differences between humans and chimpanzees, make them an unsuitable model for cancer, as well as other human diseases