1,184 research outputs found
Is economic planning hypercomputational? The argument from Cantor diagonalisation
Murphy [26] argues that the diagonal argument of the number theorist Cantor can be used to elucidate issues that arose in the socialist calculation debate of the 1930s. In particular he contends that the diagonal argument buttresses the claims of the Austrian economists regarding the impossibility of rational planning.We challenge Murphyâs argument, both at the number theoretic level and from the standpoint of economic realism
Personnel techniques necessary to maximize bio-barrier integrity at a Martian receiving laboratory
The planning of biological isolation measures for the Mars Surface Sample Return Mission is discussed in terms of personnel and organizational management. Deficiencies in past operation of the Lunar Receiving Laborator are analyzed. It was found that the failure to clearly define relationship among the government agencies involved and to effectively integrate their objectives and responsibilities was a major cause of Laboratory deficiencies. Possible solutions to these problems are presented for application to future missions
Initial learning scenarios based on the computational thinking evaluation for the course Programming fundamentals at INACAP
The paperâs objective is present the design and the planning of
initial learning scenarios for the course Programming
Fundamentals, from the evaluation of computational thinking to
new students of the careers Computer engineering and
Programmer analyst of the Technological University of Chile and
Training Center Technical respectively at INACAP, to favor the
motivation and autonomy of study through the recognition of
skills and the use of the instructional design of the face-to-face
course. The proposal is based on correspondence with three of five
change trends that integrated the educational model. Regarding
the Knowledge society, promote recognition of the individuality
of the student as a person who will do university studies, that is,
the scenarios respond to the fact that each person learns
differently. In the Training of competences, contribute with
preventive actions that the teacher communicates when there is a
lack of specific skills. Finally, in the Flexibility and articulation,
provide a diagnostic tool that favors the recognition of previous
competences to have an articulated beginning of studies based on
the needs of the student. Consequently, contribute to the
INACAPÂŽs educational model
Forage Quality of White Clover (\u3cem\u3eTrifolium Repens\u3c/em\u3e L.) X Ball Clover (\u3cem\u3eT.nigrescens Viv.\u3c/em\u3e) Hybrids Over Three Harvest Years
Introgression of reproductive traits from the annual, profusely flowering species ball clover into white clover is one route to improve seed yields in T.repens. The interspecific cross produced F1, backcross 1 (BC1), backcross 2 (BC2) and backcross 3 (BC3) plants with white clover as recurrent parent (Marshall et al., 2002). These hybrids were found to be comparable with white clover for yield and persistency but produced 30% more flowers and their forage quality, relative to white clover was investigated
Forage Quality of White Clover (\u3cem\u3eTrifolium Repens\u3c/em\u3e L.) X Caucasian Clover (\u3cem\u3eT.ambiguum\u3c/em\u3e Bieb.) Hybrids Over Three Harvest Years
Interspecific hybrids have been produced from crosses of white clover, a stoloniferous species with Caucasian clover, a rhizomatous species. Using white clover as the recurrent parent first and second generation backcross (BC1 and BC2) plants have been produced that have both rhizomes and stolons and are more drought tolerant than white clover (Marshall et al., 2001). Forage quality of these interspecific hybrids was investigated to determine whether introgression of the rhizomatous trait has any impact on forage quality
Perspectives: Quantum Mechanics on Phase Space
The basic ideas in the theory of quantum mechanics on phase space are
illustrated through an introduction of generalities, which seem to underlie
most if not all such formulations and follow with examples taken primarily from
kinematical particle model descriptions exhibiting either Galileian or
Lorentzian symmetry. The structures of fundamental importance are the relevant
(Lie) groups of symmetries and their homogeneous (and associated) spaces that,
in the situations of interest, also possess Hamiltonian structures. Comments
are made on the relation between the theory outlined and a recent paper by
Carmeli, Cassinelli, Toigo, and Vacchini.Comment: "Quantum Structures 2004" - Meeting of the International Quantum
Structures Association; Denver, Colorado; 17-22 July, 200
Lipidomic Analysis of Plasma from Healthy Men and Women Shows Phospholipid Class and Molecular Species Differences between Sexes
The phospholipid composition of lipoproteins is determined by the specificity of hepatic phospholipid biosynthesis. Plasma phospholipid 20:4n-6 and 22:6n-3 concentrations are higher in women than in men. We used this sex difference in a lipidomics analysis of the impact of endocrine factors on the phospholipid class and molecular species composition of fasting plasma from young men and women. Diester species predominated in all lipid classes measured. 20/54 Phosphatidylcholine (PtdCho) species were alkyl ester, 15/48 phosphatidylethanolamine (PtdEtn) species were alkyl ester, and 12/48 PtdEtn species were alkenyl ester. There were no significant differences between sexes in the proportions of alkyl PtdCho species. The proportion of alkyl ester PtdEtn species was greater in women than men, while the proportion of alkenyl ester PtdEtn species was greater in men than women. None of the phosphatidylinositol (PtdIns) or phosphatidylserine (PtdSer) molecular species contained ether-linked fatty acids. The proportion of PtdCho16:0_22:6, and the proportions of PtdEtn O-16:0_20:4 and PtdEtn O-18:2_20:4 were greater in women than men. There were no sex differences in PtdIns and PtdSer molecular species compositions. These findings show that plasma phospholipids can be modified by sex. Such differences in lipoprotein phospholipid composition could contribute to sexual dimorphism in patterns of health and disease
Differential postprandial incorporation of 20:5n-3 and 22:6n-3 into individual plasma triacylglycerol and phosphatidylcholine molecular species in humans
The mechanisms by which digested fat is absorbed and transported in the circulation are well documented. However, it is uncertain whether the molecular species composition of dietary fats influences the molecular species composition of meal-derived lipids in blood. This may be important because enzymes that remove meal-derived fatty acids from the circulation exhibit differential activities towards individual lipid molecular species. To determine the effect of consuming oils with different molecular compositions on the incorporation of 20:5n-3 and 22:6n-3 into plasma lipid molecular species. Men and women (18 - 30 years) consumed standardised meals containing 20:5n-5 and 22:6n-3 (total 450mg) provided by an oil from transgenic Camelina sativa (CSO) or a blended fish oil (BFO) which differed in the composition of 20:5n-3 and 22:6n-3 â containing molecular species. Blood was collected during the subsequent 8 hours. Samples were analysed by liquid chromatography-mass spectrometry. The molecular species composition of the test oils was distinct from the composition of plasma triacylglycerol (TG) or phosphatidylcholine (PC) molecular species at baseline and at 1.5 or 6 hours after the meal. The rank order by concentration of both plasma PC and TG molecular species at baseline was maintained during the postprandial period. 20:5n-3 and 22:6n-3 were incorporated preferentially into plasma PC compared to plasma TG. Together these findings suggest that the composition of dietary lipids undergoes extensive rearrangement after absorption, such that plasma TG and PC maintain their molecular species composition, which may facilitate lipase activities in blood and/or influence lipoprotein structural stability and function
The role of mutation rate variation and genetic diversity in the architecture of human disease
Background
We have investigated the role that the mutation rate and the structure of genetic variation at a locus play in determining whether a gene is involved in disease. We predict that the mutation rate and its genetic diversity should be higher in genes associated with disease, unless all genes that could cause disease have already been identified.
Results
Consistent with our predictions we find that genes associated with Mendelian and complex disease are substantially longer than non-disease genes. However, we find that both Mendelian and complex disease genes are found in regions of the genome with relatively low mutation rates, as inferred from intron divergence between humans and chimpanzees, and they are predicted to have similar rates of non-synonymous mutation as other genes. Finally, we find that disease genes are in regions of significantly elevated genetic diversity, even when variation in the rate of mutation is controlled for. The effect is small nevertheless.
Conclusions
Our results suggest that gene length contributes to whether a gene is associated with disease. However, the mutation rate and the genetic architecture of the locus appear to play only a minor role in determining whether a gene is associated with disease
Calibration of the length of a chain of single gold atoms
Using a scanning tunneling microscope or mechanically controllable break
junctions it has been shown that it is possible to control the formation of a
wire made of single gold atoms. In these experiments an interatomic distance
between atoms in the chain of ~3.6 Angstrom was reported which is not
consistent with recent theoretical calculations. Here, using precise
calibration procedures for both techniques, we measure length of the atomic
chains. Based on the distance between the peaks observed in the chain length
histogram we find the mean value of the inter-atomic distance before chain
rupture to be 2.6 +/- 0.2 A . This value agrees with the theoretical
calculations for the bond length. The discrepancy with the previous
experimental measurements was due to the presence of He gas, that was used to
promote the thermal contact, and which affects the value of the work function
that is commonly used to calibrate distances in scanning tunnelling microscopy
and mechanically controllable break junctions at low temperatures.Comment: 6 pages, 6 figure
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