18 research outputs found
SHIP DESIGN AND PRODUCTION FACILITIES: COST-EFFECTIVENESS ANALYSIS OF ACHIEVING A 355-SHIP FLEET
The current goal for the United States Navy is to achieve a 355-ship fleet by 2034 and 500 ships by 2045, according to the March 2020 Report to Congress on the Annual Long-Range Plan for Construction of Naval Vessels for Fiscal Year 2020. To achieve this goal, ship service lives will need to be extended and shipbuilding will need to occur. Given the current budgetary constraint, this project explores the cost effectiveness between four approaches to vessel construction: 1) U.S. naval designs built at U.S. yards, 2) commercial and foreign designs built at U.S. yards, 3) foreign designs built at partner foreign yards, and 4) commercial U.S. designs built at foreign yards. The cost effectiveness analysis took into account the need to preserve the U.S. naval industrial base as well as economic benefits and other advantages and disadvantages of U.S. shipbuilding as opposed to foreign shipbuilding for various design types. Based on the Constellation Class Frigate design, analysis indicates that the United States produces warships at a greater cost than its fellow European NATO member states. The United States is also less productive and maintains a lower capacity to produce warships. This analysis provides reasonable evidence to shift production of warships overseas, but it must be done in a balanced way that maximizes the cost-savings and allows the United States to continue to lead the way in next-generation technology.Lieutenant, United States NavyLieutenant, United States NavyApproved for public release. distribution is unlimite
Strong decrease of the activation energy as a function of A1 content in FeAlx alloys (x ≦ 30 at.%) deduced from kinetic measurements of ordering
Mitochondrial DNA analysis shows a Near Eastern Neolithic origin for domestic cattle and no indication of domestication of European aurochs
The extinct aurochs (Bos primigenius primigenius) was a large type of cattle that ranged over almost the whole Eurasian continent. The aurochs is the wild progenitor of modern cattle, but it is unclear whether European aurochs contributed to this process. To provide new insights into the demographic history of aurochs and domestic cattle, we have generated high-confidence mitochondrial DNA sequences from 59 archaeological skeletal finds, which were attributed to wild European cattle populations based on their chronological date and/or morphology. All pre-Neolithic aurochs belonged to the previously designated P haplogroup, indicating that this represents the Late Glacial Central European signature. We also report one new and highly divergent haplotype in a Neolithic aurochs sample from Germany, which points to greater variability during the Pleistocene. Furthermore, the Neolithic and Bronze Age samples that were classified with confidence as European aurochs using morphological criteria all carry P haplotype mitochondrial DNA, suggesting continuity of Late Glacial and Early Holocene aurochs populations in Europe. Bayesian analysis indicates that recent population growth gives a significantly better fit to our data than a constant-sized population, an observation consistent with a postglacial expansion scenario, possibly from a single European refugial population. Previous work has shown that most ancient and modern European domestic cattle carry haplotypes previously designated T. This, in combination with our new finding of a T haplotype in a very Early Neolithic site in Syria, lends persuasive support to a scenario whereby gracile Near Eastern domestic populations, carrying predominantly T haplotypes, replaced P haplotype-carrying robust autochthonous aurochs populations in Europe, from the Early Neolithic onward. During the period of coexistence, it appears that domestic cattle were kept separate from wild aurochs and introgression was extremely rare
Age- and sex-dependent profiles of APP fragments and key secretases align with changes in despair-like behavior and cognition in young APPSwe/Ind mice
Mitochondrial DNA analysis shows a Near Eastern Neolithic origin for domestic cattle and no indication of domestication of European aurochs
The extinct aurochs (Bos primigenius primigenius) was a large type of cattle that ranged over almost the whole Eurasian continent. The aurochs is the wild progenitor of modem cattle, but it is unclear whether European aurochs contributed to this process. To provide new insights into the demographic history of aurochs and domestic cattle, we have generated high-confidence mitochondrial DNA sequences from 59 archaeological skeletal finds, which were attributed to wild European cattle populations based on their chronological date and/or morphology. All pre-Neolithic aurochs belonged to the previously designated P haplogroup, indicating that this represents the Late Glacial Central European signature. We also report one new and highly divergent haplotype in a Neolithic aurochs sample from Germany, which points to greater variability during the Pleistocene. Furthermore, the Neolithic and Bronze Age samples that were classified with confidence as European aurochs using morphological criteria all carry P haplotype mitochondrial DNA, suggesting continuity of I-ate Glacial and Early Holocene aurochs populations in Europe. Bayesian analysis indicates that recent population growth gives a significantly better fit to our data than a constant-sized population, an observation consistent with a postglacial expansion scenario, possibly from a single European refugial population. Previous work has shown that most ancient and modern European domestic cattle carry haplotypes previously designated T. This, in combination with our new finding of a T haplotype in a very Early Neolithic site in Syria, lends persuasive support to a scenario whereby gracile Near Eastern domestic populations, carrying predominantly T haplotypes, replaced P haplotype-carrying robust autochthonous aurochs populations in Europe, from the Early Neolithic onward. During the period of coexistence, it appears that domestic cattle were kept separate from wild aurochs and introgression was extremely rare