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Alexander von Humboldt’s maps, graphs and illustrations contain a great deal of detail, but in the available rare editions they are hardly visible to the naked eye. In many editions they have been reduced. In a digital library, they will become accessible in their entirety, and Internet technology will reproduce them in a form that overcomes the limitations of the original printing. The user will be able to enlarge the images and see details that might have been overlooked in the past. The Humboldt’s digital library will adhere to the standards for digital libraries established by the Open Archives Initiative (OAI) and the tools EPRINTS and DSPACE to provide the Web services and determine the most effective way to establish dynamic linking and knowledge based searching of information within the archive.
The future of biological diversity in a crowded world (Ernst Mayr Lecture on 29th October 2002)
(2006)
Some drawings from the >Paper Museum< of Cassiano dal Pozzo and the Berlin Codex Destailleur >D<
(2004)
Socioeconomic inequalities are functions not only of intrinsic differences between persons or groups, but also of the dynamics of their interactions. Inequalities can arise and become stabilized if there are advantages (such as generalized wealth including “human capital”) which are self-enhancing, whereas depletion of limiting resources is widely distributed. A recent theory of biological pattern formation has been generalized, adapted and applied to deal with this process. Applications include models for the non-Gaussian distribution of personal income and wealth, for overall economic growth in relation to inequalities and for effects of uncoupling strategies between developing and developed countries. Note added after publication: The equations (14) for the model of the income distribution, with its characteristic non-Gaussian extension towards higher incomes (fig.4), are closely related to the Fokker-Planck equation that is widely applied in many fields of physics.
Responding to the Antique : a rediscovered Roman Circus Sarcophagus and its Renaissance Afterlife
(2005)
Validity of physical laws for any aspect of brain activity and strict correlation of mental to physical states of the brain do not imply, with logical necessity, that a complete algorithmic theory of the mind-body relation is possible. A limit of decodability may be imposed by the finite number of possible analytical operations which is rooted in the finiteness of the world. It is considered as a fundamental intrinsic limitation of the scientific approach comparable to quantum indeterminacy and the theorems of logical undecidability. An analysis of these limits, applied to dispositions of future behaviour, suggests that limits of decodability of the psycho-physic relation may actually exist with respect to brain states with self-referential aspects, as they are involved in mental processes. Limits for an algorithmic theory of the mind-body problem suggested by this study are formally similar to other intrinsic limits of the scientific method such as quantum indeterminacy and mathematical undecidability which are also related to self-referential operations. At the metatheoretical level, hard sciences, despite their reliability, universality and objectivity, depend on metatheoretical presuppositions which allow for multiple philosophical interpretations.
Aggregates of previously isolated cells of Hydra are capable, under suitable solvant conditions, of regeneration forming complete animals. In a first stage, ecto- and endodermal cells sort out, producing the bilayered hollow structure characteristic of Hydra tissue; thereafter, heads are formed (even if the original cell preparation contained no head cells), eventually leading to the separation of normal animals with head, body column and foot. Hydra appears to be the highest type of organism that allows for regeneration of the entire structure from random cell aggregates. The system is particularly useful for studying cell interactions, tissue polarity, pattern formation, and cell differentiation.
Non-Oberbeck-Boussinesq (NOB) effects on the Nusselt number Nu and Reynolds number Re in strongly turbulent Rayleigh-Benard convection in liquids were investigated both experimentally and theoretically. In the experiment, the heat current, the temperature difference, and the temperature at the horizontal mid-plane were measured. Three cells of different heights L, all filled with water and all with aspect ratio T close to 1 were used. For each L, about 1.5 decades in Ra were covered, together spanning the ränge 108 < Ra < 1011. For the largest temperature difference between the bottom and top plates of ? = 40K the kinematic viscosity and the thermal expansion coefficient, due to their temperature dependence, varied by more than a factor of two. The Oberbeck-Boussinesq (OB) approximation of temperature independent material parameters thus was no longer valid. The ratio Ï? of the temperature drops across the bottom and top thermal boundary layers became as small as Ï? = 0.83, as compared to the ratio Ï? = 1 in the OB case. Nevertheless, the Nusselt number Nu was found to be only slightly smaller (at most 1.4%) than in the next larger cell with the same Rayleigh number, where the material parameters were still nearly height-independent. The Reynolds numbers in the OB and NOB case agreed with each other within the experimental resolution of about 2%, showing that NOB effects for this parameter were small as well. Thus Nu and Re are rather insensitive against even significant deviations from OB conditions. Theoretically, we first account for the robustness of Nu with respect to NOB corrections: the NOB effects in the top boundary layer cancel those which arise in the bottom boundary layer as long as they are linear in the temperature difference ?. The net effects on Nu are proportional to ?2 and thus increase only slowly and still remain minor despite drastic material parameter changes. We then extend the Prandtl-Blasius boundary-layer theory to NOB Rayleigh-Benard flow with temperature dependent viscosity and thermal diffusivity. This allows the calculation of the shift of the bulk temperature, the temperature drops across the boundary layers, and the ratio Ï? without introducing any fitting parameter. The calculated quantities are in very good agreement with experiment. When in addition we use the experimental finding that for water the sum of the top and bottom thermal boundary-layer widths (based on the slopes of the temperature profiles at the plates) remains unchanged under NOB effects within experimental resolution, the theory also gives the measured small Nusseltnumber reduction for the NOB case. In addition, it predicts an increase by about 0.5% of the Reynolds number, which is also consistent with the experimental data. By theoretically studying hypothetical liquids with only one of the material parameters being temperature dependent, we shed further light on the origin of NOB corrections in water: While the NOB deviation of x from its OB value Ï? = 1 mainly originates from the temperature dependence of the viscosity, the NOB correction of the Nusselt number primarily originates from the temperature dependence of the thermal diffusivity. Finally, we give the predictions from our theory for the NOB corrections if glycerol is used as operating liquid.
The principal objective of this article is to reflect (in a philosophical manner) on recent developments in moral legislation in The Netherlands. The term ›moral legislation‹ refers to all forms of legislation on issues which can be regarded as ›moral‹ – such as euthanasia and animal experimentation. The reason for focussing on The Netherlands is that, on an international level, it is a country which has gained a reputation for being ›liberal‹, and is therefore admired by some and held in abhorrence by others.
The short paper introduces the concept of possible branches of double-stranded DNA (later sometimes called palindromes): Certain sequences of nucleotides may be followed, after a short unpaired stretch, by a complementary sequence in reversed order, such that each DNA strand can fold back on itself, and the DNA assumes a cruciform or tree-like structure. This is postulated to interact with regulatory proteins.
Mind, Matter and Mathematics
(2008)
Among mass digitization methods, double-keying is considered to be the one with the lowest error rate. This method requires two independent transcriptions of a text by two different operators. It is particularly well suited to historical texts, which often exhibit deficiencies like poor master copies or other difficulties such as spelling variation or complex text structures. Providers of data entry services using the double-keying method generally advertise very high accuracy rates (around 99.95% to 99.98%). These advertised percentages are generally estimated on the basis of small samples, and little if anything is said about either the actual amount of text or the text genres which have been proofread, about error types, proofreaders, etc. In order to obtain significant data on this problem it is necessary to analyze a large amount of text representing a balanced sample of different text types, to distinguish the structural XML/TEI level from the typographical level, and to differentiate between various types of errors which may originate from different sources and may not be equally severe. This paper presents an extensive and complex approach to the analysis and correction of double-keying errors which has been applied by the DFG-funded project “Deutsches Textarchiv” (German Text Archive, hereafter DTA) in order to evaluate and preferably to increase the transcription and annotation accuracy of double-keyed DTA texts. Statistical analyses of the results gained from proofreading a large quantity of text are presented, which verify the common accuracy rates for the double-keying method.