17,210 research outputs found
The role of entanglement in dynamical evolution
Entanglement or entanglement generating interactions permit to achieve the
maximum allowed speed in the dynamical evolution of a composite system, when
the energy resources are distributed among subsystems. The cases of
pre-existing entanglement and of entanglement-building interactions are
separately addressed. The role of classical correlations is also discussed.Comment: 5 pages, 1 figure. Revised versio
Graduate Education in the Southwest
The preliminary study presented herewith had its inception in conversations with Mr. J. Erik Jonsson early in 1958 when he outlined to me the serious problems facing the intellectual and economic growth of the Southwest in this technological age. Mr. Jonsson pointed out that many of the leaders of the Southwest community realized the imperative need for the generation of an intellectual and scientific climate in the region to ensure its healthy development. To achieve this climate, the graduate education in the region must be augmented
Forecast of World Ocean Objectivities
National Ocean Goals must be supported by a series of discreet objectives which concurrently enhance World Ocean Goals. In general terms these goals are: Improve the Ocean Environment, Promote Economic Development of Ocean Resources, Increase Scientific Knowledge of the Ocean, Assure World Peace and Security, and Enhance International Understanding.
The Forecast of World Ocean Objectives has been developed through the year 2000. These objectives have been established in accordance with a time sequence of activities associated with a horizontal consideration of the world ocean
Observations on the composition of the blood in the neonatal period
It has been realised for many years that the infants
of diabetic mothers have notably high foetal and neonatal
mortality rates, the reasons for which remain obscure.
These infants tend to be large, puffy and hyperkinetic.
If they are delivered at term, the mortality rate is very
high. Even if pregnancy is terminated two or three weeks
earlier, the incidence of respiratory distress and of
pulmonary hyaline membrane syndrome is high.Typertrophy of the pancreatic islet cells in such
infants has been established (Driscoll, Benirschke and Curtis,
1960). Pederson (1952) considers that this is a result
of stimulation of the foetus by maternal hyperglycaemia.
There is evidence that these infants become hypoglycaemic
immediately after birth (Komrower, 1954; Farquhar, 1961).
Some evidence of adrenocortical disturbance is present
(Farquhar, 1958). There are also some indications of
acidosis (Ibid).This study was begun to investigate the possibility that
there might be a disturbance in lipid and lipoprotein
metabolism in these infants, since it is already known that
such a disturbance exists in the mothers (Albrink and Nan,
1958).Information about normal serum lipid concentrations
in blood, at birth and in the neonatal period, is limited
so that any study of the infants of diabetic mothers
necessitates a parallel study of infants of normal mothers.
In the course of obtaining blood specimens from so called
"normal infants ", a considerable number of samples were
obtained from infants whose mothers had various ante- ï_atal
complications. These were notably toxaemia and abortive
tendencies. The investigation has therefore been extended
to cover these groups.Obtainiir_ blood specimens was naturally a rather
erratic process, dependin_ entirely on the availability of
hospital staff. In order that the intervening periods
might be occupied constructively, certain subsidiary
investigations were begun.To supplement the earlier work in the Department of
Child Life and Health in this University by Dr. J. W. Farquhar
on adrenocortical disturbances in the infants of diabetic
mothers, a very limited investigation of the urinary
excretion of 17- ketosteroids and l7ketogenic steroids has
been made in newborn infants. Difficulties in obtaining
complete twenty -four hour urine collections are considerable.
The amount of blood necessary for studying serum cortico
steroid concentrations is prohibitive in infants. Therefore
only a small number of urinary steroid estimations were made.Finally some information has been collected on the
amino -acid content of urine and serum in the neonatal period
in both normal and abnormal infants.The scope of the work to be described in this thesis
may be summarised as follows:1. The estimation of serum lipid and lipoprotein lipid
concentrations in the cord blood of infants, including
those with both normal and abnormal pre- and post natal
histories. The term "lipid" includes total lipid, total
cholesterol, total esterified fatty acid and phospholipid.2. The estimation of serum lipid and lipoprotein lipid
concentrations in the first week of life in the infants
of diabetic mothers.3. The estimation of the concentrations of 17- ketosteroids
and 17- keto._,enic steroids excreted in the urine of normal
infants on the first day of life and of infants of diabetic
mothers during the first three days of life.4. A chromatographic investigation of amino acid patterns
in cord blood and in venous blood and urine during the
neonatal period in normal and some abnormal infants.The methods of chemical analysis used throughout the
investigation are given in Appendix I and the methods of
statistical analysis in Appendix II. Both appendices will
be found at the end of the thesis.General conclusions are drawn at the end of each
section and not at the end of the thesis
All-Electrical Quantum Computation with Mobile Spin Qubits
We describe and discuss a solid state proposal for quantum computation with
mobile spin qubits in one-dimensional systems, based on recent advances in
spintronics. Static electric fields are used to implement a universal set of
quantum gates, via the spin-orbit and exchange couplings. Initialization and
measurement can be performed either by spin injection from/to ferromagnets, or
by using spin filters and mesoscopic spin polarizing beam-splitters. The
vulnerability of this proposal to various sources of error is estimated by
numerical simulations. We also assess the suitability of various materials
currently used in nanotechnology for an actual implementation of our model.Comment: 10 pages, 6 figs, RevTeX
Limits to clock synchronization induced by completely dephasing communication channels
Clock synchronization procedures are analyzed in the presence of imperfect
communications. In this context we show that there are physical limitations
which prevent one from synchronizing distant clocks when the intervening medium
is completely dephasing, as in the case of a rapidly varying dispersive medium.Comment: 6 Pages. Revised version as published in PR
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