Using Geological Implications of a Physical Libration to Constrain Enceladus' Libration State

Observations of Enceladus' south pole revealed large rifts in the crust, called "tiger stripes", which exhibit higher temperatures than the surrounding terrain and are likely sources of observed eruptions. Tidal stress may periodically open the tiger stripe rifts, controlling the timing and location of eruptions. Moreover, shear motion along rifts may produce the heat to drive eruptions

Geological Implications of a Physical Libration on Enceladus

Given the non-spherical shape of Enceladus (Thomas et al., 2007), the satellite will experience gravitational torques that will cause it to physically librate as it orbits Saturn. Physical libration would produce a diurnal oscillation in the longitude of Enceladus tidal bulge which, could have a profound effect on the diurnal stresses experienced by the surface of the satellite. Although Cassini ISS has placed an observational upper limit on Enceladus libration amplitude of F < 1.5deg (Porco et al., 2006), smaller amplitudes can still have geologically significant consequences. Here we present the first detailed description of how physical libration affects tidal stresses and how those stresses then might affect geological processes including crack formation and propagation, south polar eruption activity, and tidal heating. Our goal is to provide a framework for testing the hypothesis that geologic features on Enceladus are produced by tidal stresses from diurnal physical and optical librations of the satellite

Software Reliability Issues: An Experimental Approach

In this thesis, we present methodologies involving a data structure called the debugging graph whereby the predictive performance of software reliability models can be analyzed and improved under laboratory conditions. This procedure substitutes the averages of large sample sets for the single point samples normally used as inputs to these models and thus supports scrutiny of their performances with less random input data. Initially, we describe the construction of an extensive database of empirical reliability data which we derived by testing each partially debugged version of subject software represented by complete or partial debugging graphs. We demonstrate how these data can be used to assign relative sizes to known bugs and to simulate multiple debugging sessions. We then present the results from a series of proof-of-concept experiments. We show that controlling fault recovery order as represented by the data input to some well-known reliability models can enable them to produce more accurate predictions and can mitigate anomalous effects we attribute to manifestations of the fault interaction phenomenon. Since limited testing resources are common in the real world, we demonstrate the use of two approximation techniques, the surrogate oracle and path truncations, to render the application of our methodologies computationally feasible outside a laboratory setting. We report results which support the assertion that reliability data collected from just a partial debugging graph and subject to these approximations qualitatively agrees with those collected under ideal laboratory conditions, provided one accounts for optimistic bias introduced by the surrogate in later prediction stages. We outline an algorithmic approach for using data derived from a partial debugging graph to improve software reliability predictions, and show its complexity to be no worse than O(n2). We summarize some outstanding questions as areas for future investigations of and improvements to the software reliability prediction process

The not-so-Dark Ages: Ecology for human growth in medieval and early Twentieth Century Portugal as inferred from skeletal growth profiles

This study attempts to address the issue of relative living standards in Portuguese medieval and early 20th century periods. Since the growth of children provides a good measure of environmental quality for the overall population, the skeletal growth profiles of medieval Leiria and early 20th century Lisbon were compared. Results show that growth in femur length of medieval children did not differ significantly from that of early 20th century children, but after puberty medieval adolescents seem to have recovered, as they have significantly longer femora as adults. This is suggestive of greater potential for catch-up growth in medieval adolescents. We suggest that this results from distinct child labor practices, which impact differentially on the growth of Leiria and Lisbon adolescents. Work for medieval children and adolescents were related to family activities, and care and attention were provided by family members. Conversely, in early 20th century Lisbon children were more often sent to factories at around 12 years of age as an extra source of family income, where they were exploited for their labor. Since medieval and early 20th century children were stunted at an early age, greater potential for catch-up growth in medieval adolescents results from exhausting work being added to modern adolescent's burdens of disease and poor diet, when they entered the labor market. Although early 20th century Lisbon did not differ in overall unfavorable living conditions from medieval Leiria, after puberty different child labor practices may have placed modern adolescents at greater risk of undernutrition and poor growth. Am J Phys Anthropol, 2008. © 2008 Wiley-Liss, Inc

THE SUBTLETIES OF STRESS: A COMPARATIVE ANALYSIS OF SKELETAL LESIONS BETWEEN THE MEDIEVAL AND POST-MEDIEVAL BLACK FRIARS CEMETERY POPULATION (13TH TO 17TH CENTURIES)

The study of stress from an osteological perspective is challenging as we use skeletal remains to explore the lived experience and patterns of health. As an intricate overlap of multiple biological processes, the stress response system guides our understanding of how and why stress manifests as it does. Using traditional osteological methods of stress analysis, specifically cribra orbitalia, porotic hyperostosis and enamel hypoplastic lesions, this study focuses on the relationship between these indicators to explore differences in stress manifestation in the medieval and post-medieval periods in Denmark. Using the Black Friars cemetery population (13th – 17th centuries), results show an increase in stress from the medieval into the post-medieval period likely dictated by the strains of urbanism on a predominantly poor population. Additionally, a younger mean age at death was noted when multiple mild-moderate indicators were present as compared to one severe indicator being present. A recognition of the intricacies of the stress response effectively aids in the exploration of stress manifestation and the relationship, if any, between these well-used skeletal indicators.Michael Smith Foreign Study Supplement (771-2012-0113) (ABS); SSHRC Standard Research Grant (410-2011-1408) (RDH); and the Dr. Emöke J.E. Szathmáry Graduate Fellowship in Biological Anthropology (University of Manitoba) (ABS

Software reliability studies

There are many software reliability models which try to predict future performance of software based on data generated by the debugging process. Our research has shown that by improving the quality of the data one can greatly improve the predictions. We are working on methodologies which control some of the randomness inherent in the standard data generation processes in order to improve the accuracy of predictions. Our contribution is twofold in that we describe an experimental methodology using a data structure called the debugging graph and apply this methodology to assess the robustness of existing models. The debugging graph is used to analyze the effects of various fault recovery orders on the predictive accuracy of several well-known software reliability algorithms. We found that, along a particular debugging path in the graph, the predictive performance of different models can vary greatly. Similarly, just because a model 'fits' a given path's data well does not guarantee that the model would perform well on a different path. Further we observed bug interactions and noted their potential effects on the predictive process. We saw that not only do different faults fail at different rates, but that those rates can be affected by the particular debugging stage at which the rates are evaluated. Based on our experiment, we conjecture that the accuracy of a reliability prediction is affected by the fault recovery order as well as by fault interaction

Validation of the new interpretation of Gerasimov’s nasal projection method for forensic facial approximation using CT data

The most common method to predict nasal projection for the purpose of forensic facial approximation is Gerasimov’s two-tangent method. It was recently argued that previous validation studies did not properly perform Gerasimov’s original methodology and a revised set of guidelines was proposed. The aim of this study was to compare the accuracy of the different version of the two-tangent method using a sample of 66 postmortem cranial CT data. Intraobserver error was evaluated using a subsample of 10 individuals and the results demonstrated that experience affects the accuracy. Overall, the revised guidelines consistently resulted in smaller mean difference from the true tip. On the other hand, none of the methods were found to be statistically accurate (p>0.05) in positioning the tip of the nose (absolute distance > 5 mm). These results seem to support that Gerasimov’s method was not properly performed and the new guidelines should be used instead

Análisis de conceptos del Derecho Laboral Individual en español y en finés

Tämän pro gradu -tutkielman aiheena on Espanjan ja Suomen työlainsäädännön terminologia ja erityisesti individuaalisen työoikeuden piiriin kuuluva käsitteistö. Individuaalisella työoikeudella tarkoitetaan työntekijän ja työnantajan välistä työsuhdetta sääteleviä normeja. Tutkielman empiirinen osuus koostuu terminologisesta sanastotyöstä, jossa espanjalaisille työoikeuden käsitteille etsitään käsitevastineita Suomen lainsäädännöstä. Sanastotyö perustuu käsiteanalyysiin, jossa kartoitetaan käsitteiden sisältö ja käsitteiden väliset suhteet. Analyysin kohteena olevien espanjan- ja suomenkielisten termien käsitesisällön vastaavuutta arvioidaan osana sanastotyötä. Tutkimuksen korpus sisältää 42 individuaalisen työoikeuden käsitettä ja 51 espanjan- ja 46 suomenkielistä termiä, joilla näihin käsitteisiin viitataan lakitekstissä. Teoreettisen perustan tutkimukselle muodostaa Cabrén (1999) kommunikatiivinen terminologian teoria, joka korostaa erikoiskielen termien olevan osa luonnollista kieltä. Tutkimuksen näkökulma on deskriptiivinen ja käsitekeskeinen. Lähtökohtana ei ole hypoteesia tai erityisiä tutkimuskysymyksiä, sillä työn ainoa tavoite on kuvailla analyysin kohteena olevaa terminologiaa. Analyysi ei sen vuoksi tarjoa myöskään varsinaisia tutkimustuloksia. Sanastotyön tarjoamien tietojen valossa voidaan kuitenkin todeta, että juridisten termien semanttisia eroja ja vastaavuuksia on vaikea havaita muulla tavoin kuin tutkimalla perusteellisesti lakeja, joissa kyseiset termit esiintyvät. Lakimuutokset johtavat yleensä myös laissa käytettyjen termien käsitteellisiin muutoksiin. Lisäksi on huomattava, että juridisten termien käsitesisältö on aina riippuvainen oikeusjärjestelmästä, jossa termejä käytetään. Näiden seikkojen vuoksi on syytä suhtautua kriittisesti yleiskielen sanakirjojen tarjoamiin juridisiin vastineisiin.Siirretty Doriast