Understanding as explanatory knowledge: The case of Bjorken scaling

In this paper, we develop and refine the idea that understanding is a species of explanatory knowledge. Specifically, we defend the idea that S understands why p if and only if S knows that p, and, for some q, S’s true belief that q correctly explains p is produced/maintained by reliable explanatory evaluation. We then show how this model explains the reception of James Bjorken’s explanation of scaling by the broader physics community in the late 1960s and early 1970s. The historical episode is interesting because Bjorken’s explanation initially did not provide understanding to other physicists, but was subsequently deemed intelligible when Feynman provided a physical interpretation that led to experimental tests that vindicated Bjorken’s model. Finally, we argue that other philosophical models of scientific understanding are best construed as limiting cases of our more general model.     

Neuropeptide Y: the universal soldier

The peptidic neurotransmitter neuropeptide Y (NPY) has received great attention because it has been implicated in the regulation of several organ systems. In particular, NPY is involved in the regulatory loops that control food intake in the hypothalamus and appears also to be important for regulating the activity of neuroendocrine axes under poor metabolic conditions. Furthermore, NPY exerts vasoconstrictive action on the vasculature and potentiates the actions of many other vasoconstrictors. In addition, it was demonstrated to have trophic properties and could therefore contribute to cardiovascular remodeling. These various effects plus a number of others make NPY an attractive target for the potential treatment of human diseases, such as obesity, metabolic disorders, hypertension and heart failure. Received 17 July 2002; received after revision 7 November 2002; accepted 29 November 2002 RID="*" ID="*"Corresponding author.     

Bronchial asymmetry and Fibonacci scaling

The irregular branching pattern of the bronchial tree in multiple mammalian species is consistent with a process of morphogenetic self-similarity described by Fibonacci scaling.     

Bronchial asymmetry and Fibonacci scaling

Summary The irregular branching pattern of the bronchial tree in multiple mammalian species is consistent with a process of morphogenetic self-similarity described by Fibonacci scaling.     

The moon-test in Newton's Principia: Accuracy of inverse-square law of universal gravitation

Communicated by J. D. North     

The brachymorphic mutation of mice and altered developmental patterns of limb bud 3':5' cyclic adenosine monophosphate

Concentrations of cyclic AMP (cAMP) were determined in paired fore and hind limbs from day 12-16 of development in murine fetuses homozygous for the brachymorphic (bm) mutation and normal controls. A developmental rise in cAMP occurred 1 day earlier in bm/bm than in +/+ hind limbs and cAMP was higher in day-13 bm/bm than in +/+ fore limbs. Since cAMP is well documented to stimulate chondrogenic differentiation, premature cartilage determination secondary to altered levels of cAMP could play a role in bm/bm short-limbed dwarfism.     

超温水体蒸发系数通用公式的研究与应用

在环境参数可控风洞中对影响蒸发的风速、水气温差、水温、相对湿度等物理量进行系统试验。试验结果表明蒸发系数取决于风速的强迫对流和水气温差的自由对流。分析试验数据得到了水面蒸发系数的建议公式和相应的水面散热系数公式以及附加蒸发系数公式。用参数变幅很大的天然水体和受纳废热水体的实测资料和研究成果检验了建议公式的通用性。建议公式已为DL／T5084-98《电力工程水文技术规程》及GB／T50102-2003《工业循环水冷却设计规范》推荐应用于计算水面蒸发、水面散热及附加蒸发。     

The effect of scale changes on repetitive patterns: Influence of 6-aminonicotinamide on feather germ number

There are many examples of patterned developing systems which are size invariant: if the total size of the system is reduced, then the pattern responds by changing its scale in such a way that the number of pattern elements remains constant. This phenomenon is one of the bases which underaly the formulation of the concept of positional information, one of the great unifying ideas in developmental biology. However, there are less common examples of patterns which are size dependent. In these, alterations of overall size lead to a reduction in pattern elements. Such size-dependent patterns are therefore of theoretical interest. Here we describe how the number of feather germs along the wing bud of the developing chick embryo responds to shortening of the limb, and consider the implications of these observations.     

The variability of patterns of sexual dimorphism in the hominoid skull

Summary Univariate and multivariate statistical analyses are applied to a number of cranial dimensions and angles from living hominoids in order to investigate the patterns of sexual dimorphism in these groups. Clear differences in patterns of cranial sexual dimorphisms are demonstrated not only between genera but also within a single species (Homo). These differences overlay the common finding of a sexual size difference in all groups. The results imply that caution is required in using the sexual dimorphisms of living hominoids as models for those anticipated in fossils.     

The variability of patterns of sexual dimorphism in the hominoid skull

Univariate and multivariate statistical analyses are applied to a number of cranial dimensions and angles from living hominoids in order to investigate the patterns of sexual dimorphism in these groups. Clear differences in patterns of cranial sexual dimorphisms are demonstrated not only between genera but also within a single species (Homo). These differences overlay the common finding of a sexual size difference in all groups. The results imply that caution is required in using the sexual dimorphisms of living hominoids as models for those anticipated in fossils.     

The development of gene therapy for diseases of the lung

The development of a successful gene therapy has many stages, including preclinical testing in animal models and proof of principle clinical studies. A variety of diseases affect the lung, which are candidates for gene therapy; this review will mainly focus on the diseases that have attracted the most attention and have therefore yielded the most progress, namely lung cancer and the monogenic disorder cystic fibrosis. Knowledge gained from clinical studies could eventually be applied to more complex lung conditions such as acute respiratory distress syndrome and asthma. In addition, increased gene transfer efficiencies could be obtained by appropriate selection of the gene transfer vector and mode of delivery.Received 8 August 2003; received after revision 10 September 2003; accepted 17 September 2003     

Endurance training and antioxidants of lung

Summary Mice and rats were adjusted to daily treadmill training programs, which were heavy enough to increase the oxidative capacity of skeletal muscles. Endurance training did not affect the activities of catalase and glutathione peroxidase and the concentration of vitamin E in the lungs of mice and rats. Thus increased ventilation and oxygen utilization induced by exercise training do not modify lung antioxidants, in contrast to hyperoxia and hypoxia.This study was supported by the Academy of Finland and the Research Council for Physical Education and Sport (Ministry of Education, Finland). We thank Mr Matti Virtanen for skillful technical assistance.     

The chromosome banding patterns of the aardvarkOrycteropus afer (Tubulidentata,Orycteropidae)

Summary C- and G-banding patterns ofOrycteropus afer are described on the basis of fibroblast cultures obtained from a female individual.This work was supported in part by a research grant DEB 76-10580 from the National Science Foundation.     

Endurance training and antioxidants of lung

Mice and rats were adjusted to daily treadmill training programs, which were heavy enough to increase the oxidative capacity of skeletal muscles. Endurance training did not affect the activities of catalase and glutathione peroxidase and the concentration of vitamin E in the lungs of mice and rats. Thus increased ventilation and oxygen utilization induced by exercise training do not modify lung antioxidants, in contrast to hyperoxia and hypoxia.     

The dynamics of serum lipoprotein patterns in vitamin C-saturated and vitamin C-deficient guinea-pigs after carbon tetrachloride poisoning

Zusammenfassung Aus einer Experimentalarbeit, bei welcher die Konzentration der papierelektrophoretisch gewonnenen Lipoproteinfraktionen des Serums Vitamin-C-gesättigter und avitaminöser Meerschweinchen verglichen wurde, geht hervor, dass die Frühstadien der C-Avitaminose den Spiegel der ₁-Lipoproteine bedeutend erhöhen und den der ₂-Lipoproteine herabsetzen. Dies und die Ergebnisse der durch Tetrachlorkohlenstoff hervorgerufenen Leberschädigung weisen auf die Tatsache hin, dass die Frühstadien der C-Avitaminose den Mechanismus, der den normalen Spiegel der Serumlipoproteine reguliert, beeinflussen, obwohl gleichzeitig die Regenerierungsprozesse der durch Tetrachlorkohlenstoff geschädigten Leber der Beeinflussung entzogen bleiben.