Quantitative Support (quantitative + support)

Distribution by Scientific Domains

Selected Abstracts

Dynamical similarity of explosions at Stromboli volcano

S. De Martino
SUMMARY We analyse Strombolian explosions recorded with broadband seismometers to quantify the degree of similarity among explosions. First, we construct the trajectory space. This reconstruction is analogous to that of phase space but, unlike the phase space which relies on the analysis of a single trajectory of a dynamic system, the trajectory space takes into account many trajectories of the dynamic process to study the overlapping properties. Based on the scaling of distances between each pair of histories, it is possible to evaluate the dimension of the trajectory space. We consider the different explosions as different trajectories and, after normalizing all the records, we find that the scaling region is spread over less than one order of magnitude. This absence of scaling implies that all the trajectories cover the same attractor in the trajectory space, and that the trajectories are generated by the same dynamic system. Accordingly, we conclude that all the events are very similar to each other. This result is confirmed by the energy distribution of these events. Standard techniques of energy estimation are inadequate in this case, and we propose an evaluation method based on a quantity that is proportional to energy. The distribution function of this quantity, calculated on 580 events, displays a log-normal behaviour with very low variability (less than two orders of magnitude in energy). These results provide quantitative support for the observation that there is a great degree of similarity among Strombolian explosions and support the idea that a dynamic model underlying these events can be elaborated through the study of just one event. [source]

Critical Whiteness Theories and the Evangelical "Race Problem": Extending Emerson and Smith's Divided by Faith

In their 2000 book,Divided by Faith, Michael Emerson and Christian Smith use the case of evangelical Christians to demonstrate how uncompromising individualist ideals get in the way of clear thinking and decisive action about racial inequalities in contemporary American society. We use insights developed from whiteness studies and critical race theory to sharpen and further extend this analysis. More specifically, we suggest: (1) that anti-black stereotypes may be subtler, more pervasive, and more functionally necessary than Emerson and Smith assume; and (2) that the individualistic ideals Emerson and Smith focus on are not race neutral but, instead, are part of a taken-for-granted and vigorously defended majority white culture and identity. These points are developed through a theoretical reconstruction of Emerson and Smith's argument and a reevaluation of their methodological approach and data. Finally, we present data from a recent national survey of race and religion in American life that provide preliminary quantitative support for our revisionist claims. [source]

Evidence for selection on coloration in a Panamanian poison frog: a coalescent-based approach

Jason L. Brown
Abstract Aim, The strawberry poison frog, Oophaga pumilio, has undergone a remarkable radiation of colour morphs in the Bocas del Toro archipelago in Panama. This species shows extreme variation in colour and pattern between populations that have been geographically isolated for < 10,000 years. While previous research has suggested the involvement of divergent selection, to date no quantitative test has examined this hypothesis. Location, Bocas del Toro archipelago, Panama. Methods, We use a combination of population genetics, phylogeography and phenotypic analyses to test for divergent selection in coloration in O. pumilio. Tissue samples of 88 individuals from 15 distinct populations were collected. Using these data, we developed a gene tree using the mitochondrial DNA (mtDNA) d-loop region. Using parameters derived from our mtDNA phylogeny, we predicted the coalescence of a hypothetical nuclear gene underlying coloration. We collected spectral reflectance and body size measurements on 94 individuals from four of the populations and performed a quantitative analysis of phenotypic divergence. Results, The mtDNA d-loop tree revealed considerable polyphyly across populations. Coalescent reconstructions of gene trees within population trees revealed incomplete genotypic sorting among populations. The quantitative analysis of phenotypic divergence revealed complete lineage sorting by colour, but not by body size: populations showed non-overlapping variation in spectral reflectance measures of body coloration, while variation in body size did not separate populations. Simulations of the coalescent using parameter values derived from our empirical analyses demonstrated that the level of sorting among populations seen in colour cannot reasonably be attributed to drift. Main conclusions, These results imply that divergence in colour, but not body size, is occurring at a faster rate than expected under neutral processes. Our study provides the first quantitative support for the claim that strong diversifying selection underlies colour variation in the strawberry poison frog. [source]

The type specimen (LB1) of Homo floresiensis did not have Laron Syndrome

Dean Falk
Abstract The type specimen (LB1) of Homo floresiensis has been hypothesized to be a pathological human afflicted with Laron Syndrome (LS), a type of primary growth hormone insensitivity (Hershkovitz et al.: Am J Phys Anthropol 134 [2007] 198,208). Comparing measurements, photographs and three-dimensional, computed-tomography reconstructions of LB1 with data and diagnoses from the literature on LS, we critically evaluate numerous skull and postcranial traits that Hershkovitz etal. identified as being shared by LB1 and patients with LS. The statements regarding most of these traits are new to the clinical literature and lack quantitative support. LB1 and patients with LS differ markedly in the size and shape of the cranium; thickness and pneumatization of cranial bones; morphology of the face, mandible, teeth, and chin; form of the shoulder, wrist, and pelvis; and general body proportions including relative foot size. Claims that patients with LS are similar to LB1 in displaying protracted scapulae, short clavicles, low degrees of humeral torsion, flaring ilia, and curved tibiae are not supported by data or corroborating images. Some points of similarity (e.g., femoral neck-shaft angle, femoral bicondylar angle, and estimated stature) can be found in other hominins, and cannot be considered diagnostic. From our review and analysis, we conclude that LB1 did not suffer from LS. Am J Phys Anthropol, 2009. 2009 Wiley-Liss, Inc. [source]

Interaction Appearance Theory: Changing Perceptions of Physical Attractiveness Through Social Interaction

Kelly Fudge Albada
Can the effectiveness of your social interaction with a prospective romantic partner make him or her see you as more physically attractive? If so, under what conditions does this process occur? These questions prompted the development of a theoretical perspective to explain this process. Interaction appearance theory (IAT) requires (a) a set of beliefs about the importance and interdependence of physical attractiveness and social interaction in a satisfactory romantic relationship; (b) an initial perception of the other's physical attractiveness that is not high enough to trigger the pursuit of a romantic relationship but is not low enough to preclude it; (c) social interaction that is eventually perceived as more desirable than the perception of the other's physical attractiveness; and (d) bringing the discrepant perceptions into alignment by actually seeing the other person as more physically attractive. While providing support for the theory, the interviews in Study 1 also provided insights into how the process can vary. Study 2, using a sample of new daters, provided quantitative support for the belief structure. Study 3, using diaries, found changes in perceptions of a partner's physical attractiveness to be a function of positive and negative interactions. These studies provided support for IAT and the idea that perceptions of physical attractiveness can be changed by social interaction. [source]