VictorJuiz/thesis huggingface dataset:
A study of the energy levels in light nuclei

The results of some angular correlation experiments on the low lying states of 15N, 15O and 16O are presented. The result of an investigation of the lifetimes of some of the excited states of 15N and 150 are also to be found.
In Chapters 2, 3 and 4 the experimental methods and the underlying theory are discussed. The results are presented in Chapters 5 and 6 and discussed in Chapter 7.
The 15N angular correlation results
The spins of the positive parity states at 5.27, 7.15, 7.56 and 7.30 MeV were confirmed to be 5⁄2, 5⁄2, 7⁄2 and 3⁄2 respectively. The multipole mixing ratios of the de-excitation gamma rays from these levels were determined. The results were:
γ(5.27 &rightarrow; 0)   = −0.165 &pm; 0.015;   E3
M2
γ(7.15 &rightarrow; 5.27)   =   −0.04 &pm; 0.03;   E2
M1
γ(7.56 &rightarrow; 5.27)   =   −0.01 &pm; 0.03;   E2
M1
γ(7.30 &rightarrow; 0)   =   −0.07 &pm; 0.02;   M2
E1
The smaller results only have been quoted.
15O angular correlation results
The spins of the 15O levels located at 6.79 and 6.86 MeV were confirmed to be 3⁄2 and 5⁄2 respectively and the multipole mixing ratios of the de-excitation gamma rays were determined with the following result:
γ(5.24 &rightarrow; 0)   =   &plus;0.14   +0.04
−0.03
;   E3
M2
γ(6.86 &rightarrow; 5.24)   =   −0.04 &pm; 0.03;   E2
M1
γ(6.79 &rightarrow; 0)   =   −0.10 &pm; 0.02;   M2
E1
The smaller results only have been quoted
16O angular correlation results
The multipole mixing ratios for the de-excitation gamma rays from the 2−, 8.88 MeV state in 16O were investigated. Apart from the decay scheme of the level the following results were obtained.
γ(8.88 &rightarrow; 6.14)   = 2.9 &pm; 0.02;   E2
M1
| γ(8.88 &rightarrow; 7.12) |   >   2.5; E2
M1
The mass 15 lifetime results
The lifetimes of some of the excited states of 15N and 15O were investigated using the Doppler shift attenuation method. Lifetime limits were obtained for several of the levels. It was also found that:
Γ(15N, 7.56 MeV) = (0.06 &pm; 0.02) x 10−12 sec.
Γ(15O, 7.28 MeV) = (0.70 &pm; 0.15) x 10−12 sec.
Problems in group theory

Using combinatorial and character-theoretic methods the following theorems are proved.
Theorem I Let G be a finite simple group containing two non-conjugate subgroups A, B such that:
if a ε A, a &notequals; 1, then CG (a) = A; if b ε B, b &notequals; 1, then
CG(b) = B;
| NG(A)/A | = 2, | NG(B)/B | = 2.
Then G is isomorphic to some PSL (2,2a).
Theorem II Let G be a finite simple group containing a subgroup A such that:
if a ε A, a &notequals; 1, then CG(a) = A;
| NG(A)/A | = 2;
3 divides | A | .
Then G is isomorphic to some PSL (2,q).
Some studies on the ionic basis of the current-voltage relations in cardiac muscle

Measurements of the electrical properties of the cardiac Purkinje fibre membrane have been made with intracellular electrodes; and in a separate study, computations based on a mathematical model of the membrane have been performed.
Evidence has been found that the instantaneous potassium permeability of the membrane varies as a function of the difference between the K equilibrium potential and the membrane potential, rather than of the latter alone. Superimposed upon this, there is a time-dependent slow increase in K conductance on depolarization, corresponding to the delayed rectification described by the Hodgkin-Huxley relation when n2 is used in place of n4. The time constant is voltage dependent and may be up to hundreds of msec. This increase and its subsequent decline can account for repolarization from the plateau of the action potential, and for pacemaker activity. During long-lasting outward currents applied across the membrane there is a gradual depolarization of the K equilibrium potential; evidence suggests that K ions accumulate transiently in an extracellular space adjacent to the membrane.
Solutions to Noble's (1962) modified Hodgkin-Huxley equations have been computed for a membrane with part of its capacitance in series with a constant resistance. Rates of depolarization and repolarization have thereby been increased to experimentally-observed values; also, a possible explanation for the pre-plateau notch in some action potentials has resulted. An evaluation of the ramp-shaped voltage clamp as an analytical tool has been attempted, by computing solutions of the same equations under such conditions. The equations have also been solved when is a function of n2.
Studies of stimulated emission of radiation

Laser action has been observed on a nunber of 3p - 3s transitions in the infra-red in neutral atomic Carbon and Nitrogen. Mixtures of Helium or Neon with Carbon Monoxide or Nitrogen were excited with current pulses of up to 90amps and a duration of 2μsec. Depending on the pressure, current, and transition laser action occurred either during the current pulse risetime or in the afterglow. The laser tube was 2 metres long with a bore of 7mm, and was fitted with internal electrodes and Brewster angle end windows.
The time dependence of the laser output as a function of current and pressure has been investigated and the interpretation is baaed on observations of the spontaneous emission from the upper and lower levels of the laser transitions. In addition to the laser transitions, other related transitions in Carbon and Nitrogen and transitions to the metastable and resonance trapped levels of Helium and Neon were studied. Techniques have been developed to measure the populations of these metastable and resonance trapped levels by comparing the light emitted from the side of the laser tube to the light emitted from the end of the tube along the tube axis. Absolute values for the populations of the upper and lower level of the laser transition have also been obtained without the use of a calibrated detector.
The different mechanisms whereby excited states may be populated in a gas discharge are discussed, and cross-sections for the different collision processes estimated. These are used together with the measured values of populations, to determine the likely dominant processes in the afterglow. Measurements of the rates of decay of the populations of the levels in Helium, Neon, Carbon and Nitrogen show a correlation between the populations of the metastable states of Helium and Neon and the 3p levels of Carbon and Nitrogen. It is therefore proposed that the dominant excitation mechanism for the 3p Carbon and Nitrogen level is

He
Ne
} Metastable + CO
N2
} =  He
Ne
} +   C*
N* } +   O
N
}
Energy considerations require that, in general the molecule be in an excited vibrational state produced by excitation during the current pulse. From the measured populations, a cross-section for this reaction is estimated and found to be 7 x 10-16cm2, with vibrational temperatures in the region of 25,000°K.
Experimental investigations in elementary particle physics

An account is given of some of the results of an experiment undertaken by a collaboration of five British and one German Hydrogen Bubble Chamber Groups. A beam of 6 GeV/c K− mesons was injected into the British National Hydrogen Bubble Chamber at the proton synchrotron at CKPN, Geneva. A total of 300,000 pictures or 1800 kms, of K− track was scanned for interactions. The scanning measuring and identification of two classes of interaction in the Oxford sample of film are described in detail. A scheme which uses a computer to do the book keeping of the scanned information is mentioned - this was developed by the author as a result of experience with this experiment. The treatment of losses, biases and ambiguities is discussed at some length - a new method is used to correct for the lose of sigmas at small decay angles in the laboratory and a discussion of the meaning of the probability associated with a kinematic fit leads to ideas affecting the interpretation of ambiguous fits.
Special problems affecting the analysis of antibody final states are discussed and solutions put into practice. Careful treatment is given to final states which derive large weights from losses. A discussion of the optimum way of selecting resonances and choosing histogram bin sizes is to be found in an appendix. From a brief discussion of the theory of Unitary Symmetry we are lead to consider the omega minus and its quantum numbers. An original investigation by the author into the isospin of the omega takes the form of a search for s neutral baryon of strangeness −3. The fact that the state is not found is of even greater interest for the quark model of Unitary Symmetry. The latter is described briefly and a search is made for other states forbidden by the model.
A survey is made of final states containing a hyperon and mesons. Evidence in favour of a new Y&bullet;1 resonance at 1680 MeV decaying to (λπ) supports the findings of W. Derrick et al. at 5.5 GeV/c. A strong forward peak of lambdas in the lambda four pion and lambda five pion final states appears to be associated with strong production of positively charged meson resonances decaying into three pions. These resonances appear at 1100, 1500 and 164O MeV and are identified with A1, A2 and π(1640). The A2 appears to decay to (ρπ) although the data suggests that the A1 does not. Similar features were seen in the lambda four pion state at 3.5 OeV. These findings are important since the A1 has only been seen before in final states confused by "Deck" diffractive effects.
The decay correlations of the reaction K−p &rightarrow; ρ° are calculated from first principles and compared with experiment. This paves the way for the study of the double peripheral production mechanism. Detailed discussion of two final states (K−p &rightarrow; ∑°π+π− and K−p &rightarrow; K*−π&plus;n) is used to set forth the general features of the model. It is shown that the matrix element for the former may be derived directly from that for the well known reaction π−p &rightarrow; ∑°K*° by crossing symmetry. Although the data are not definitive, they provide general for the model.
Problems in the quantum theory of many-particle systems

A finite temperature perturbation theory for the Heisenberg model of ferromagnetism is presented. A modified Wick's theorem proved for S=&half; and finite temperatures allows the terms in the expansion for the temperature dependent Green's function to be expressed by linked Feynman-like diagrams. The diagrams differ from the usual boson and fermion diagrams in the appearance of time (temperature) dependent dotted lines between propagators reflecting the effect of spin statistics. For temperatures such that T⁄TC is finite, the diagrams for the irreducible self-energies are classified with respect to a high density parameter 1⁄Z where Z is the number of spins interacting with a given spin. The results of molecular field theory are found in first order. The next two orders in the self-energy graphs yield at low T spin wave theory and Dyson's results in Born approximation respectively. The high density classification is also verified directly at low T, and in an appendix, higher order graphs are found to yield the expressions for the lifetimes of the excitations of the system given by Tahir-Kheli and ter Haar. The magnetization expression obtained from the graphs of the first three orders yields a Curie point since the first order graphs are renormalized to include in their internal lines all graphs of all other orders considered. The Curie point found is that of molecular field theory. The expressions for the magnetization at low temperatures and near the Curie point are then used as a guide in approximating the magnetization from graphs of the first three orders at all temperatures. This approximate expression is calculated as a function of the temperature using a long range potential, and the curve is compared to the experimental results for the magnetization of Cu K2 Cl4.2H2O, a spin &half; ferromagnetic insulator with next nearest neighbour interactions. The results from the random phase approximation of Tyablikov and Englert are also compared with the experimental results, and it is seen that both curves fit within the experimental errors of the points up to T⁄TC~.6, but both fall below the experimental points as the Curie temperature is approached. The difference between the two theoretical curves is negligible.
Equilibrium studies with platinum complexes

This thesis describes the measurement of stability constants for olefins with tetrachloroplatinate(II) and silver(I) ions. The two systems studied were
ol + PtCl=4&leftrightharpoons;(ol)PtCl−3 + Cl−
and
ol + Ag(H2O)+n&leftrightharpoons;(ol)Ag(H2O)+m
where ol = olefin. The olefins studied were either unsaturated ammonium salts or unsaturated alcohols.
With platinum(II) , it is found that olefins give higher stability constants than water, lower than amines and comparable with the heavier halides. With silver (I), olefins give stability constants lower than amines and the heavier halides, but comparable to water and fluoride.
In the case of platinum(II) , enthalpy and entropy values were obtained from the temperature dependence of the stability constants. It was found that the overall stability constant was strongly dependent on the entropy change. The variation in the entropy change is ascribed largely to variations in the solvation energies of the ligands and complexes.
Comparison of the enthalpy values for different olefins shovs four main trends.
There is an increase in ΔH from allX+ to butX+(X a NH3, NEt3 and AsEt3).
There is an increase in ΔH in the series allX+ where X = Net3, NMe3, NHEt2, NH2Et and NH3.
There is an increase in ΔH for allY on replacing Y=NH+3 by Y=OH.
There is a decrease in ΔH in the series CH2=CH-CH2-NH+3,CH2=CH-CH(CH3)-NH+3 and trans-CH3-CH=CH-CH2-NH+3.
Trends 1. and 2. can be explained in terms of an inductive effect. Both trends indicate that the π-acceptor capacity of the olefin is more important than the δ-donor capacity for the formation of stable platinum-olofin bonds. Trend 3. is shown to be largely the result of solvation energy changes. Trend 4. is shown to result from a combination of steric and inductive effects.
It was found that the stability constants for silver(I)-olefin complexes are much lover than for platinum(II)-olefin complexes. This can be explained in terms of the nature of the metal-olofin bond in the two series of complexes. It was also found that silver(I) showed a much greater preference than platinum(II) for the uncharged alcoholic ligands rather than the positively charged ammonium ligands. This can be explained in terms of the electrostatic interaction between the positively charged ammonium group and the central metal group.
From a study of the ultra-violet spectra of the platinum(II)-olefin complexes, it is shown that the relative energies of the d-orbitals in these complexes are dx2-y2>dxy>d,sub>z
2>dyz>dxz.
Calvin's theology of the word of God : an examination of the Christocentric character of Calvin's theology with reference to his teaching concerning man's knowledge of God, the providence of God, the law of God, and the life of the Christian man

In our time we, of course, face problems in Christian dogmatics within a different context from Calvin. let in the Reformed Churches we believe we would greatly impoverish ourselves if we departed from his locus or disregarded his seminal teaching. Thus, the underlying question of the thesis is: can Reformed theology go the same fundamental way as Calvin and yet go further, i.e., let Calvin's theology extend and make itself explicit in the face of our theological problems? We think so. We have chosen three areas in which to test this assertion, all of which are lively areas of discussion in modern theology: natural knowledge of God, history and ethics. In each of the respective chapters we try first to represent what Calvin said; then we suggest the problems these doctrines of Calvin present for modern (Reformed) theology. Finally, we let Calvin's doctrine of the Word extend and make explicit his statements in each of these areas; i.e., knowledge, history and ethics, in the face of the problems of today. In order to follow this procedure we set forth in the First Chapter the heart and norm for all of Calvin's theology, his doctrine of the Word, In sum, then, we let Calvin's doctrine of the Word clarify the Christological character of Calvin's doctrines of our knowledge of God, the Providence of God, the Law of God and the life of the Christian man in the face of contemporary theological discussion.
Voltaire and Clio : from history to story

This thesis proposes to examine Voltaire as 'literary' historian and to compare the theory and practice of his histories with those of contemporary historiographers and historians. The works selected for focus are Voltaire's Histoire de Charles XII (1730) and Le Siècle de Louis XIV (1751).
Section I, 'History Voices', centres on the enunciated theory and the actual practice of contemporary history. The prefatory writing of a selection of historians (from among Voltaire's sources) is analysed to identify a prefatory programme. This is subsequently compared to the contemporary practice of writing history and it reveals an intriguing degree of divergence concerning attitudes towards authority, objectivity and truth. Similar analysis is applied to Voltaire's theoretical writing on historiography, revealing a 'historian's voice'. While Voltaire and his contemporaries all discuss questions of the historical author, subject, style, truth, aims and reader, actual contemporary history (excluding Voltaire) discloses a monotonal texture, uniquely concerned with the chosen subject of history.
Section II, 'Story Voices', focuses on Voltaire's use of different textual levels in his composition of the story of his histories, that is, the telling, evaluation and presentation of historical and non-historical material within history. Analysis is made of structure, style, use of anecdotes, voices and echoes to investigate the development of a polytonal history which is simultaneously historical and contemporary, analytical and polemical, general and personal. In comparing Voltaire's histories to contemporary histories and to his own enunciated theories of historiography, textual analysis also reveals ambiguities in fact and fiction, in the historical and the storical, in historiography and narrative. A salient feature of the literariness of Voltaire's histories is the presence of duality, ironic tone and polytonal voices, all of which are audible beneath and within the official history. This literariness underlies and comprises the very vitality of Voltaire's history.
The sequence and characterisation of ?-globin haplotypes in human populations

Genetic variation at the human a-globin gene complex has only been characterised to date as haplotypes - a linked set of 7 RFLPs and 2 VNTRs - and not at the sequence level. However, an understanding of the extent of sequence variability at this locus, and its relation to underlying mutational processes, is of interest to studies of both molecular and population genetics.
This variation has been investigated by the development of a PCR haplotyping and direct sequencing protocol. Sequencing of 6 RFLP-containing regions of the haplotype in different human populations demonstrates that all (-) RFLPs have the same sequence, regardless of geographical origin. Additional sequence variation is found surrounding the RFLP sites, indicating that the overall level of variation at this locus is comparable to that at other loci, although a higher mutation rate is shown in an inter-species comparison. The additional polymorphic sites are concentrated in only three regions; a survey comprising a total ~280kb indicates that this sequence polymorphism is generated and influenced by localised gene conversion, which was not evident at the RFLP level. PCR analysis of the 2 VNTRs in human populations demonstrates considerable size variation in human populations, not detected by previous haplotyping protocols. There is also extensive internal sequence variation in the VNTRs (in a total survey of ~50 kb), apparently accumulating in a polar fashion and governed primarily by gene conversion, as reported at other VNTR loci. In addition, flanking sequence variation is identified which undergoes conversion, although not in concert with changes in the nearby repeat structure.
Consideration of the association of variation, at both the unique and repeated sequence regions, with RFLP α-haplotypes demonstrates that haplotypes differ in age, and allows relationships between them to be determined. The resulting haplotype network has similarities to that determined from β-globin gene variation; the implications for recent human evolution are discussed.
International development of the Senegal River

The thesis examines the political influences that have shaped what is ostensibly a functional programme for the international development of the Senegal River by the three participating states of Mali, Mauritania, and Senegal. Construction of the two major first phase projects began in late 1981 - a 186millionsaltbarrierdaminthedeltaanda
680 million hydro-electric storage d^m upstream in Mali. The thesis finds that the functional rationale for making use of the valuable international resource is undermined by the political concessions, compromises, and accommodations the basin states and the donors who finance the projects need to make to sustain international cooperation.
An NMR study of biological phosphate interactions

An investigation is made of the interactions between a variety of small molecule phosphates and amines, and in particular of triethylenetetramine with hexametaphosphate, pyrophosphate, tripolyphosphate, ADP and ATP and of cyclic triethylenetriamine with hexametaphosphate. For each phosphate/amine pair, observed changes in the pH dependence of 1H and 31P nmr chemical shift are used to calculate the effect of interaction on the pKa of the two species present and an association constant is evaluated at one particular pH value. These data are then combined to evaluate association constants for a variety of protonation states of the phosphate and amine. Strength of association is interpreted in terms of electrostatic charge and its spatial distribution, comparison is made with Mg2+ and Ca2+ complexes and biological relevance is discussed.
The interaction of yeast PGK with its substrates is investigated by using the (500MHz and 300MHz) 1H nmr spectrum of the enzyme and (250MHz) 31P nmr spectra of its substrates. On the basis of pH dependence, comparison with the spectrum of horse PGK and T2 relaxation data,1H nmr resonances are assigned to surface residues. In particular, resonances are assigned to the three active site histidines (nos. 62,167 and 170), and to the exposed histidine and methionine residues. A series of comparatively well-resolved upfield shifted aromatic peaks, including a relatively exposed tyrosine peak is tentatively assigned to the interdomain hinge region of the protein.
The effects of MgADP, MgATP and the non-reacting nucleotide analogue MgAMPPNP on the yeast PGK spectrum are characterised. The line-broadening reagent Gd3+is used to distinguish between direct influence and conformational effects. The triose phosphate substrate 3-PG is added to the enzyme as are the anionic probes [Co(CN)6] , [Cr(CN)6]and [Fe(CN)6] I and the nature of anion binding in the active groove of the protein and elsewhere on its surface is investigated. Movement of the two PGK domains is investigated in three models of the ternary complex: (i) with MgAMPPNP and 3-PG, (ii) with the elongated nucleotide A4P, and (iii) with a mutant form of the enzyme (his388 -gln388). The PGK/substrate interaction is interpreted in terms of the phosphate/amine model.