On the computation of confluent hypergeometric functions for large imaginary part of parameters b and z

The final publication is available at http://link.springer.com/chapter/10.1007%2F978-3-319-42432-3_30We present an efficient algorithm for the confluent hypergeometric functions when the imaginary part of b and z is large. The algorithm is based on the steepest descent method, applied to a suitable representation of the confluent hypergeometric functions as a highly oscillatory integral, which is then integrated by using various quadrature methods. The performance of the algorithm is compared with open-source and commercial software solutions with arbitrary precision, and for many cases the algorithm achieves high accuracy in both the real and imaginary parts. Our motivation comes from the need for accurate computation of the characteristic function of the Arcsine distribution or the Beta distribution; the latter being required in several financial applications, for example, modeling the loss given default in the context of portfolio credit risk.Peer ReviewedPostprint (author's final draft

Virtue Theory as a Feminist Ethical Framework

In recent decades, feminists have pointed out how prominent ethical theories are primarily concerned with establishing rules of conduct between strangers who share (or are theorized as if they share) the same social status. As Claudia Card points out, such theories outline explicit expectations and rewards of formal relationships; these relationships characterize formal institutions, such as law and business, and the considerations of upper-class men who predominate in such institutions. An ethics which focuses on the impersonal application of rules risks overlooking attentiveness to personal needs, a crucial quality in caring relationships which women and poorer classes have had primary responsibility for sustaining. For example, women have had greater pressure than men to be attentive to the particular needs of their children and households, while poorer workers have had to attend to the idiosyncrasies of their customers and employers. Moreover, contractarian theories of ethics idealize an equality of status which is not always possible or desirable: Ethical theories should be able to inform us in how we ought to treat our children, or how people should take care of others with disabilities. I will argue that virtue theories can be particularly responsive to these feminist criticisms. Since a feminist ethical theory must be able to evaluate and critique both feminine and masculine practical considerations, I will examine how virtue theories emphasize caring qualities (e.g. personality and emotional sensitivity) alongside some endorsed by contractarian theories (e.g.distributive justice and impersonal respect). I will then discuss how understanding gendered notions of care can highlight unjust social practices, by reference to Card’s distinction of formal institutions and Annette Baier’s notion of caring professions. (Specifically, Baier holds that women are pressured to take up “caring” professions thought to require emotional sensitivity and attentiveness to particular needs, e.g. nursing or customer service.) Furthermore, I will point out how emphasizing moral agents’ personal qualities and circumstances can inform conditions for just laws, as exemplified by Rosalind Hursthouse’s ethical examination of abortion. In these ways, virtue theory can provide a moral context within which values of justice and care are jointly cultivated

Molecular studies for linkage analysis and determination of quantitative trait loci (QTL) for acid soil tolerance in maize (Zea mays L.)

Acid soils include approximately 4 billion hectares of the earth\u27s surface. Soils with pH \u3c 5.6, deficiency of calcium, magnesium, phosphorous, molybdenum, iron, and Al saturation \u3e35% with P level \u3c16 parts per million are considered acidic for maize (Zea mays L.). Because of acid soils, fewer and smaller roots are produced, reducing the plant\u27s capacity to uptake water and nutrients from the soil. The objectives of this study are to develop the marker linkage map for an acid soil tolerant maize F 2 segregating population, to dissect the quantitative trait loci (QTLs) for several traits, and to determine whether these QTLs could be used in a marker-assisted selection program for acid tolerance in maize. An F2 population of 221 individuals was genotyped at 118 SSR loci and 214 F3 families were evaluated in an alpha lattice design (22 x 10). The trials were grown in five environments, three acidic (V55, V65, and AYA65) and two normal fertile (PAL and TUR) in Colombia. Female flowering, male flowering, anthesis-silking-interval, yield, ears per plant, and plant and ear height were measured. Except for male and female flowering and anthesis-silking interval at AYA65, acid soil environments tended to have less the genetic variance. The estimates of heritabilities (h2) in acid environments were generally lower for all traits but yield in V65 (36%) and AYA65 (60%). The total length of the SSR linkage map was 1836.2 cM with a mean density of 15.56 cM. For all traits evaluated and based on the composite interval mapping analysis (LOD = 2.5), there were 66 QTLs identified for each environment. Thirteen QTLs were detected across acidic soils, 33 across normal-fertile soils, and 40 QTLs across all environments. In this study, no QTL with major effects were identified. QTLs had low single and total R2 values, for individual environments and across environments

An antidote for hawkmoths: a response to recent climate-skeptical arguments grounded in the topology of dynamical systems

In a series of recent papers, two of which appeared in this journal, a group of philosophers, physicists, and climate scientists have argued that something they call the `hawkmoth effect' poses insurmountable difficulties for those who would use non-linear models, including climate simulation models, to make quantitative predictions or to produce `decision-relevant probabilites.' Such a claim, if it were true, would undermine much of climate science, among other things. Here, we examine the two lines of argument the group has used to support their claims. The first comes from a set of results in dynamical systems theory associated with the concept of `structural stability.' The second relies on a mathematical demonstration of their own, using the logistic equation, that they present using a hypothetical scenario involving two apprentices of Laplace's omniscient demon. We prove two theorems that are relevant to their claims, and conclude that both of these lines of argument fail. There is nothing out there that comes close to matching the chara

An antidote for hawkmoths: a response to recent climate-skeptical arguments grounded in the topology of dynamical systems

In a series of recent papers, two of which appeared in this journal, a group of philosophers, physicists, and climate scientists have argued that something they call the `hawkmoth effect' poses insurmountable difficulties for those who would use non-linear models, including climate simulation models, to make quantitative predictions or to produce `decision-relevant probabilites.' Such a claim, if it were true, would undermine much of climate science, among other things. Here, we examine the two lines of argument the group has used to support their claims. The first comes from a set of results in dynamical systems theory associated with the concept of `structural stability.' The second relies on a mathematical demonstration of their own, using the logistic equation, that they present using a hypothetical scenario involving two apprentices of Laplace's omniscient demon. We prove two theorems that are relevant to their claims, and conclude that both of these lines of argument fail. There is nothing out there that comes close to matching the chara

An Antidote for Hawkmoths: On the prevalence of structural chaos in non-linear modeling

This paper deals with the question of whether uncertainty regarding model structure, especially in climate modeling, exhibits a kind of ``chaos.'' Do small changes in model structure, in other words, lead to large variations in ensemble predictions? More specifically, does model error destroy forecast skill faster than the ordinary or ``classical" chaos inherent in the real-world attractor? In some cases, the answer to this question seems to be ``yes." But how common is this state of affairs? And are there precise mathematical results that can help us answer this question? We examine some efforts in the literature to answer this last question in the affirmative and find them to be unconvincing

El valor social de la confianza

Ante la crisis de confianza que se experimenta en la sociedad actual, se examina su importancia y los modos para generarla y recuperarla. Se muestran algunos ejemplos del ámbito empresarial