Een concentratieprobleem bij B.J. van der Walt

B.J. van der Walt’s concentration problem This contribution probes the concept of secularism, a key notion of B.J. van der Walt’s “Transforming power” (2007). It is found that Van der Walt’s interpretation of secularism rests on a double assumption. The first assumption is that human nature is intrinsically religious. Humans cannot live without putting their trust in something. The second is that this religious nature manifests itself in “concentrated” ways, rather than dispersing itself over a plurality of objects. These assumptions in tandem explain why Van der Walt holds the view that atheism, agnosticism and even overt indifference in matters of faith are at heart propelled by convictions that share the main features of positive religions. It also explains why he assumes that all these convictions tend towards one and the same goal: to gain dominance in the public realm. This article is sympathetic towards the first assumption, and skeptical towards the second. It is argued that the “concentration- thesis” fails to do justice to world and life-views that obviously do not claim total allegiance. To illustrate this point it turns to the phenomenon of “multiple religious participation”, as well as to different strands within contemporary humanism. It concludes that the main problem may well be that secular culture has little to offer to satisfy the innate religious drive in humankind

The return of religion

Religion is back in Philosophy as a respectable subject. Part 1 first charts what MacIntyre, Taylor and Derrida have meant in this regard. Subsequently, it turns to the Enlightenment to determine what constituted the breakthrough. It is found that even where the Enlightenment gave maximum room to religion i.e. as a civic religion and as “religion of the heart”) it still excluded a constitutive relation to a transcendent revelation. Part 2 centres on the religion-faith distinction in reformational philosophy. Similar to the Enlightenment, religion is understood as part of human nature. However, human nature itself is conceived as intrinsically religious and depending for its light on revelation. Secondly, “religion” in this context also encompasses idols and religious substitutes. Thus, it directs attention to shopping malls, football stadiums, health policy, et cetera, as possible contexts of a return of religion. Examples show that this has become a popular approach. However, most of the publications surveyed fail to distinguish between an “analogical” and a “pistically qualified” use of religion, and are open to exaggerations (the shopping mall and football stadiums as temples, etc.). At this junction, the relevance is shown of the religion-faith distinction as well as of Elaine Botha’s theory of metaphors. The epilogue offers an integration of parts one and two

The role of sweet and savoury taste in food intake and food preferences

Background and aim The sensory attributes of food play a key role in the selection and termination of meals and their rewarding properties. The majority of our foods are either sweet or savoury tasting. In addition, within our food range, savoury-tasting foods contain in general higher levels of protein. The effect of specific taste modalities on human food intake, however, requires further clarification. The primary aim of this thesis was to investigate the role of sweet and savoury taste in food intake and food preferences. The secondary aim was to provide more insight into the processes of explicit and implicit liking and wanting, to be able to identify underlying reward mechanisms involved in food intake behaviour. Methods We conducted series of experiments where healthy young adults participated. We started by investigating the difference between a sweet and savoury taste on satiation, independent of palatability, texture, energy density, and macronutrient composition (n=64). Next, the effect of sweet and savoury taste of a single meal on subsequent satiety and food preferences was investigated (n=61). To further explore the effect of taste in the context of a complete diet on satiety and food preferences, the effect of three 24-h diets that differed only in taste (predominantly sweet tasting, predominantly savoury tasting, or a mixture of sweet and savoury tasting) were compared (n=39). Next, we separated the influence of taste from within-meal protein content on satiety and food preferences, by comparing the effect of sweet and savoury high and low protein single meals (n=60). Finally, the effect of long-term protein status on satiety and food preferences was investigated by comparing the effect of two 14-d diets that differed in protein content (a low protein diet vs. a high protein diet) (n=37). Results Sweet and savoury taste, independent of palatability, texture, energy density, and macronutrient composition, did not differ in their effect on satiation and satiety in terms of subsequent ad libitum intake. Sweet and savoury taste did differ in their effect on subsequent food preferences. In general, after eating a food with a certain taste, appetite for foods with a similar taste was lower than for foods with a dissimilar taste, hence, a clear transfer effect of sensory specific satiety was demonstrated. This transfer effect was not equipotent for sweet and savoury taste; after eating a sweet single meal or sweet 24-h diet, preferences for sweet and savoury foods did not differ. Eating a savoury single meal or savoury 24-h diet, however, led to a clear preference for sweet foods. Neither sweet or savoury tasting single meals nor sweet or savoury 24-h diets shifted food preferences towards high or low protein foods. It was shown that protein content of a meal, independent of taste, did not have an effect on satiety and food preference. We did observe, however, an effect of protein status: after a 14-d low protein diet, there was an increase in ad libitum protein intake, compared to after a 14-d high protein diet, while total energy intake was not different. In addition, food preference for savoury high protein foods was increased. Regarding the different components of food reward it was demonstrated that in all studies both explicit and implicit measures correlated with several aspects of eating. It appeared that in a controlled setting, i.e. in the sensory booths, explicit processes played a stronger determining role in satiation (meal size) than implicit processes. Food choices appeared to be made on a more unconscious level. In a setting where subjects could behave more naturally (i.e. self-selection and serving of foods in a relaxed environment where subjects could sit and eat together), implicit, unconscious processes seemed to explain food intake behaviour more than explicit processes. When subjects experienced protein shortage, after the 14-d low protein diet, it appeared that implicit processes of wanting played a stronger determining role in decisions about what to eat. Conclusion Sweet and savoury taste do not differ in their effect on satiation or satiety in terms of subsequent ad libitum intake. The taste of a meal or diet does have a large effect on subsequent food preferences, thereby showing a clear transfer effect which is not equipotent for sweet and savoury taste. Savoury taste exerts a stronger modulating effect on subsequent food preferences than sweet taste. Sweet and savoury taste of a single meal or 24-h diet do not differ in their effect on food preferences for high or low protein foods. In addition, within-meal protein content seems not to influence satiety or food preferences. A low protein status, however, through selective reduction of dietary protein intake, elicits compensatory changes in food intake and food preferences to restore adequate protein status. It appears that both conscious (explicit) and unconscious (implicit) processes are involved in satiation and food choice. The role implicit motivational processes play in driving food choice is not static, but appears to vary. This is especially the case when homeostasis is challenged (by depleting macronutrient stores), where implicit processes of wanting appear to play a stronger determining role in decisions about what to eat. </p

Proton structure corrections to hyperfine splitting in muonic hydrogen

We present the derivation of the formulas for the proton structure-dependent terms in the hyperfine splitting of muonic hydrogen. We use compatible conventions throughout the calculations to derive a consistent set of formulas that reconcile differences between our results and some specific terms in earlier work. Convention conversion corrections are explicitly presented, which reduce the calculated hyperfine splitting by about 46 ppm. We also note that using only modern fits to the proton elastic form factors gives a smaller than historical spread of Zemach radii and leads to a reduced uncertainty in the hyperfine splitting. Additionally, hyperfine splittings have an impact on the muonic hydrogen Lamb shift/proton radius measurement, however the correction we advocate has a small effect there.Comment: 6 pages, 3 figure

Self-Consistent Data Analysis of the Proton Structure Function g1 and Extraction of its Moments

The reanalysis of all available world data on the longitudinal asymmetry A|| is presented. The proton structure function g1 was extracted within a unique framework of data inputs and assumptions. These data allowed for a reliable evaluation of moments of the structure function g1 in the Q2 range from 0.2 up to 30 GeV2. The Q2 evolution of the moments was studied in QCD by means of Operator Product Expansion (OPE).Comment: Proceeding of 3rd International Symposium on the Gerasimov-Drell-Hearn Sum Rule and its extensions, Old Dominion University, Norfolk, Virginia June 2-5, 200

Higher twist analysis of the proton g_1 structure function

We perform a global analysis of all available spin-dependent proton structure function data, covering a large range of Q^2, 1 < Q^2 < 30 GeV^2, and calculate the lowest moment of the g_1 structure function as a function of Q^2. From the Q^2 dependence of the lowest moment we extract matrix elements of twist-4 operators, and determine the color electric and magnetic polarizabilities of the proton to be \chi_E = 0.026 +- 0.015 (stat) + 0.021/-0.024 (sys) and \chi_B = -0.013 -+ 0.007 (stat) - 0.010/+0.012 (sys), respectively.Comment: 6 pages, 2 figures, to appear in Phys. Lett.

De waardering van de eindigheid in het latere denken van Hegel

Smit, M.C. [Promotor

Cross Sections for the Exclusive Photon Electroproduction on the Proton and Generalized Parton Distributions

Unpolarized and beam-polarized fourfold cross sections (d(4)sigma / dQ(2)dx(B)dtd phi) for the ep - \u3e e\u27p\u27gamma reaction were measured using the CLAS detector and the 5.75-GeV polarized electron beam of the Jefferson Lab accelerator, for 110 (Q(2), x (B), t) bins over the widest phase space ever explored in the valence-quark region. Several models of generalized parton distributions (GPDs) describe the data well at most of our kinematics. This increases our confidence that we understand the GPD H, expected to be the dominant contributor to these observables. Through a leading-twist extraction of Compton form factors, these results support the model predictions of a larger nucleon size at lower quark-momentum fraction x (B)

A theory of normed simulations

In existing simulation proof techniques, a single step in a lower-level specification may be simulated by an extended execution fragment in a higher-level one. As a result, it is cumbersome to mechanize these techniques using general purpose theorem provers. Moreover, it is undecidable whether a given relation is a simulation, even if tautology checking is decidable for the underlying specification logic. This paper introduces various types of normed simulations. In a normed simulation, each step in a lower-level specification can be simulated by at most one step in the higher-level one, for any related pair of states. In earlier work we demonstrated that normed simulations are quite useful as a vehicle for the formalization of refinement proofs via theorem provers. Here we show that normed simulations also have pleasant theoretical properties: (1) under some reasonable assumptions, it is decidable whether a given relation is a normed forward simulation, provided tautology checking is decidable for the underlying logic; (2) at the semantic level, normed forward and backward simulations together form a complete proof method for establishing behavior inclusion, provided that the higher-level specification has finite invisible nondeterminism.Comment: 31 pages, 10figure