Variation reduction in a wafer fabrication line through inspection optimization

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1997, and Thesis (M.S.)--Massachusetts Institute of Technology, Sloan School of Management, 1997.Includes bibliographical references (p. 44).by John W. Bean.M.S

The Scottish invasion of pink salmon in 2017

No abstract available

Influence of Oxygen at Atmospheric and High Pressure on the Developing Tooth Germ in Rat Embryos

Repeated exposure of pregnant rats to oxygen at high pressure (65 psi) twice a day for seven days increased the height of the tooth germ and ameloblastic layer of the embryo, but the width and odontoblastic layer were not changed. Exposure of pregnant rats to oxygen at atmospheric pressure stimulated the body growth of the embryo in utero.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68256/2/10.1177_00220345720510052501.pd

Differences in growth pattern of bone and incisor of rats exposed to O2 atmospheric and high pressure

Three groups of young rats (age 22 days) were exposed intermittently (49 times), over a period of 44 days, group 1 to O2 at atmospheric pressure (OAP), group 2 to O2 at high pressure (OHP) (60 psig) and the third to air at atmospheric pressure (AAP) as controls. The average food consumption for the AAP group was 18.85 g, for the OAP 17.55 g and for the OHP 17.07 g per rat per day. The change in the body weights of each of these groups was followed throughout the experiment which continued 13 days after the last exposures. Bone growth of the maxilla, mandible and femur diaphysis and incisor growth were not altered by the OAP exposures, but were decreased by the OHP exposures; incisor growth, however, was increased. Hardness of the bone (by Tukon Hardness Tester) was increased in the OAP and OHP exposures as compared with that of the AAP, but the hardness of the incisors was not altered.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/34114/1/0000398.pd

RADseq and mate choice assays reveal unidirectional gene flow among three lamprey ecotypes despite weak assortative mating: Insights into the formation and stability of multiple ecotypes in sympatry

Adaptive divergence with gene flow often results in complex patterns of variation within taxa exhibiting substantial ecological differences among populations. One example where this may have occurred is the parallel evolution of freshwater‐resident nonparasitic lampreys from anadromous‐parasitic ancestors. Previous studies have focused on transitions between these two phenotypic extremes, but here, we considered more complex evolutionary scenarios where an intermediate freshwater form that remains parasitic is found sympatrically with the other two ecotypes. Using population genomic analysis (restriction‐associated DNA sequencing), we found that a freshwater‐parasitic ecotype was highly distinct from an anadromous‐parasitic form (Qlake‐P = 96.8%, Fst = 0.154), but that a freshwater‐nonparasitic form was almost completely admixed in Loch Lomond, Scotland. Demographic reconstructions indicated that both freshwater populations likely derived from a common freshwater ancestor. However, while the nonparasitic ecotype has experienced high levels of introgression from the anadromous‐parasitic ecotype (Qanad‐P = 37.7%), there is no evidence of introgression into the freshwater‐parasitic ecotype. Paradoxically, mate choice experiments predicted high potential for gene flow: Males from all ecotypes were stimulated to spawn with freshwater‐parasitic females, which released gametes in response to all ecotypes. Differentially fixed single nucleotide polymorphisms identified genes associated with growth and development, which could possibly influence the timing of metamorphosis, resulting in significant ecological differences between forms. This suggests that multiple lamprey ecotypes can persist in sympatry following shifts in adaptive peaks, due to environmental change during their repeated colonization of post‐glacial regions, followed by periods of extensive gene flow among such diverging populations

Integrating Safeguards and Security with Safety into Design

There is a need to minimize security risks, proliferation hazards, and safety risks in the design of new nuclear facilities in a global environment of nuclear power expansion, while improving the synergy of major design features and raising operational efficiency. In 2008, the U.S. Department of Energy (DOE), National Nuclear Security Administration (NNSA) launched the Next Generation Safeguards Initiative (NGSI) covering many safeguards areas. One of these, launched by NNSA with support of the DOE Office of Nuclear Energy, was a multi-laboratory project, led by the Idaho National Laboratory (INL), to develop safeguards by design. The proposed Safeguards-by-Design (SBD) process has been developed as a structured approach to ensure the timely, efficient, and cost effective integration of international safeguards and other nonproliferation barriers with national material control and accountability, physical security, and safety objectives into the overall design process for the nuclear facility lifecycle. A graded, iterative process was developed to integrate these areas throughout the project phases. It identified activities, deliverables, interfaces, and hold points covering both domestic regulatory requirements and international safeguards using the DOE regulatory environment as exemplar to provide a framework and guidance for project management and integration of safety with security during design. Further work, reported in this paper, created a generalized SBD process which could also be employed within the licensed nuclear industry and internationally for design of new facilities. Several tools for integrating safeguards, safety, and security into design are discussed here. SBD appears complementary to the EFCOG TROSSI process for security and safety integration created in 2006, which focuses on standardized upgrades to enable existing DOE facilities to meet a more severe design basis threat. A collaborative approach is suggested

Distance Scale Zero Points from Galactic RR Lyrae Star Parallaxes

We present new absolute trigonometric parallaxes and proper motions for seven Population II variable stars—five RR Lyr variables: RZ Cep, XZ Cyg, SU Dra, RR Lyr, and UV Oct; and two type 2 Cepheids: VY Pyx and κ Pav. We obtained these results with astrometric data from Fine Guidance Sensors, white-light interferometers on Hubble Space Telescope. We find absolute parallaxes in milliseconds of arc: RZ Cep, 2.12 ± 0.16 mas; XZ Cyg, 1.67 ± 0.17 mas; SU Dra, 1.42 ± 0.16 mas; RR Lyr, 3.77 ± 0.13 mas; UV Oct, 1.71 ± 0.10 mas; VY Pyx, 6.44 ± 0.23 mas; and κ Pav, 5.57 ± 0.28 mas; an average σπ/π = 5.4%. With these parallaxes, we compute absolute magnitudes in V and K bandpasses corrected for interstellar extinction and Lutz-Kelker-Hanson bias. Using these RR Lyrae variable star absolute magnitudes, we then derive zero points for MV -[Fe/H] and MK -[Fe/H]-log P relations. The technique of reduced parallaxes corroborates these results. We employ our new results to determine distances and ages of several Galactic globular clusters and the distance of the Large Magellanic Cloud. The latter is close to that previously derived from Classical Cepheids uncorrected for any metallicity effect, indicating that any such effect is small. We also discuss the somewhat puzzling results obtained for our two type 2 Cepheids

The reintroduction of large carnivores to the Eastern Cape, South Africa: an assessment

Recently, conservation estate in South Africa's Eastern Cape Province has increased 10-fold resulting in large predators being increasingly reintroduced to restore ecological integrity and maximize tourism. We describe the reintroductions of large carnivores (>10 kg) that have occurred in the Eastern Cape and use various criteria to assess their success. Lion Panthera leo reintroduction has been highly successful with a population of 56 currently extant in the region and problems of overpopulation arising. The African wild dog Lycaon pictus population has increased to 24 from a founder population of 11. Preliminary results for spotted hyaenas Crocuta crocuta also indicate success. Wild populations of leopards Panthera pardus exist on several reserves and have been supplemented by translocated individuals, although deaths of known individuals have occurred and no estimate of reproduction is available. Cheetah Acinonyx jubatus reintroduction has also been less successful with 36 individuals reintroduced and 23 cubs being born but only 41 individuals surviving in 2005. Criteria for assessing the success of reintroductions of species that naturally occur in low densities, such as top predators, generally have limited value. Carrying capacity for large predators is unknown and continued monitoring and intensive management will be necessary in enclosed, and possibly all, conservation areas in the Eastern Cape to ensure conservation success