Examining maternal effects and genetic differentiation in P. flexilis and P. aristata to improve success of conservation actions

2013 Fall.Includes bibliographical references.As the climate changes and invasive species continue to spread, proactive management may be needed to conserve native plant populations. Selecting appropriate plant material for restoration or other actions that will sustain populations is an integral part of any such plan and must take into account genetic differentiation to limit maladaptation. Common garden studies are used to determine the genetic basis of trait variation among populations from different geographic sources. However, maternal effects, the effect of environment during offspring development, can also affect performance, complicating the interpretation of these studies. Growing one generation in a common environment can help correct for maternal effects, but is often not practical with long-lived species. Using limber pine (Pinus flexilis) and Rocky Mountain bristlecone pine (Pinus aristata) as model species, I explored the contribution of maternal effects to early seedling growth among populations in a greenhouse common garden study. I grew offspring sourced over multiple years from the same mother trees, comparing growth traits between source years. Additionally, I collected five twig clippings from the upper canopy of each mother tree and measured characteristics indicative of the relative vigor of the tree during each seed source year. There were significant (p<0.05) differences in year-to-year variation in twig growth characteristics, seed size, and seedling performance. For bristlecone pine, there was a significant positive relationship between the relative inter-annual (RIA) variation in seed mass and seedling total dry mass and a negative relationship between the RIA variation in seed mass and needle growth at 210 days. For limber pine, there were significant positive relationships between RIA variation in seed mass and cotyledon length, stem height, stem diameter, and needle length at 20, 120, and 190 days. These results a) support the hypotheses that maternal effects are evident in both P. flexilis and P. aristata and that these effects translate into variation in early seedling growth and b) suggest possibilities for statistically correcting for maternal effects in genetic differentiation common garden studies involving long-lived species. Using these data I then conducted a common garden greenhouse study to determine the degree of genetic differentiation in limber pine populations in the Southern Rockies. Mid-summer precipitation varies greatly along a latitudinal gradient throughout this region, potentially selecting for local adaptation of populations to their native moisture regime. I evaluated the differential response of seed sources from northern and southern portions of the range to different moisture regimes during early seeding growth. To test whether seedling growth traits, which are often adaptive, differed between northern and southern seed sources, I measured primary needle length, stem diameter, water potential, and biomass allocation between root and shoot before, during, and after treatments. To test for differentiation in the adaptive traits associated with water use, I also measured carbon isotope ratios (δ13C) as a proxy for water use efficiency. To account for maternal effects I used cotyledon length as a covariate, which I found in the previous study to be a good indicator of maternal year-to-year variation in seedling growth. There were significant (p<0.05) effects of source region for root length, stem diameter, needle length, and total dry mass, where seedlings from southern sources were bigger than those from northern sources. Seedlings from the north had a higher probability of mortality than those from southern populations, as did seedlings in the dry treatment. The only significant interaction between growth response and source region, signifying the possibility of local adaptation of populations, was with the carbon isotope ratio (δ13C, p<0.1). All seedlings in the dry treatment regardless of origin had higher δ13C, while seedlings in the wet treatment varied between slightly higher (southern populations) and lower (northern populations) values of δ13C. These data indicate that genetic differentiation exists among populations in the Southern Rockies, potentially increasing the risk of maladaptation when moving seed far from its source

The Effects of Stress Tensor Fluctuations upon Focusing

We treat the gravitational effects of quantum stress tensor fluctuations. An operational approach is adopted in which these fluctuations produce fluctuations in the focusing of a bundle of geodesics. This can be calculated explicitly using the Raychaudhuri equation as a Langevin equation. The physical manifestation of these fluctuations are angular blurring and luminosity fluctuations of the images of distant sources. We give explicit results for the case of a scalar field on a flat background in a thermal state.Comment: 26 pages, 1 figure, new material added in Sect. III and in Appendices B and

Appointment scheduling with unscheduled arrivals and reprioritization

Inspired by the real life problem of a radiology department in a Dutch hospital, we study the problem of scheduling appointments, taking into account unscheduled arrivals and reprioritization. The radiology department offers CT diagnostics to both scheduled and unscheduled patients. Of these unscheduled patients, some must be seen immediately, while others may wait for some time. Herein a trade-off is sought between acceptable waiting times for appointment patients and unscheduled patients’ lateness. In this paper we use a discrete event simulation model to determine the performance of a given appointment schedule in terms of waiting time and lateness. Also we propose a constructive and local search heuristic that embeds this model and optimizes the schedule. For smaller instances, we verify the simulation model as well as compare our search heuristics’ performance with optimal schedules obtained using a Markov reward process. In addition we present computational results from the case study in the Dutch hospital. These results show that a considerable decrease of waiting time is possible for scheduled patients, while still treating unscheduled patients on time

The rotating molecular core and precessing outflow of the young stellar object Barnard 1c

We investigate the structure of the core surrounding the recently identified deeply embedded young stellar object Barnard 1c which has an unusual polarization pattern as traced in submillimeter dust emission. Barnard 1c lies within the Perseus molecular cloud at a distance of 250 pc. It is a deeply embedded core of 2.4 solar masses (Kirk et al.) and a luminosity of 4 +/- 2 solar luminosities. Observations of CO, 13CO, C18O, HCO+ and N2H+ were obtained with the BIMA array, together with the continuum at 3.3 mm and 2.7 mm. Single-dish measurements of N2H+ and HCO+ with FCRAO reveal the larger scale emission in these lines, The CO and HCO+ emission traces the outflow, which coincides in detail with the S-shaped jet recently found in Spitzer IRAC imaging. The N2H+ emission, which anticorrelates spatially with the C18O emission, originates from a rotating envelope with effective radius ~ 2400 AU and mass 2.1 - 2.9 solar masses. N2H+ emission is absent from a 600 AU diameter region around the young star. The remaining N2H+ emission may lie in a coherent torus of dense material. With its outflow and rotating envelope, B1c closely resembles the previously studied object L483-mm, and we conclude that it is a protostar in an early stage of evolution. We hypothesize that heating by the outflow and star has desorbed CO from grains which has destroyed N2H+ in the inner region and surmise that the presence of grains without ice mantles in this warm inner region can explain the unusual polarization signature from B1c.Comment: 17 pages, 17 figures (9 colour). Accepted to The Astrophysical Journal. For higher resolution images, see http://astrowww.phys.uvic.ca/~brenda/preprints.htm

Spatially Explicit Data: Stewardship and Ethical Challenges in Science

Scholarly communication is at an unprecedented turning point created in part by the increasing saliency of data stewardship and data sharing. Formal data management plans represent a new emphasis in research, enabling access to data at higher volumes and more quickly, and the potential for replication and augmentation of existing research. Data sharing has recently transformed the practice, scope, content, and applicability of research in several disciplines, in particular in relation to spatially specific data. This lends exciting potentiality, but the most effective ways in which to implement such changes, particularly for disciplines involving human subjects and other sensitive information, demand consideration. Data management plans, stewardship, and sharing, impart distinctive technical, sociological, and ethical challenges that remain to be adequately identified and remedied. Here, we consider these and propose potential solutions for their amelioration

Stochastic Spacetime and Brownian Motion of Test Particles

The operational meaning of spacetime fluctuations is discussed. Classical spacetime geometry can be viewed as encoding the relations between the motions of test particles in the geometry. By analogy, quantum fluctuations of spacetime geometry can be interpreted in terms of the fluctuations of these motions. Thus one can give meaning to spacetime fluctuations in terms of observables which describe the Brownian motion of test particles. We will first discuss some electromagnetic analogies, where quantum fluctuations of the electromagnetic field induce Brownian motion of test particles. We next discuss several explicit examples of Brownian motion caused by a fluctuating gravitational field. These examples include lightcone fluctuations, variations in the flight times of photons through the fluctuating geometry, and fluctuations in the expansion parameter given by a Langevin version of the Raychaudhuri equation. The fluctuations in this parameter lead to variations in the luminosity of sources. Other phenomena which can be linked to spacetime fluctuations are spectral line broadening and angular blurring of distant sources.Comment: 15 pages, 3 figures. Talk given at the 9th Peyresq workshop, June 200

Jupyter notebooks as discovery mechanisms for open science: Citation practices in the astronomy community

Citing data and software is a means to give scholarly credit and to facilitate access to research objects. Citation principles encourage authors to provide full descriptions of objects, with stable links, in their papers. As Jupyter notebooks aggregate data, software, and other objects, they may facilitate or hinder citation, credit, and access to data and software. We report on a study of references to Jupyter notebooks in astronomy over a 5-year period (2014-2018). References increased rapidly, but fewer than half of the references led to Jupyter notebooks that could be located and opened. Jupyter notebooks appear better suited to supporting the research process than to providing access to research objects. We recommend that authors cite individual data and software objects, and that they stabilize any notebooks cited in publications. Publishers should increase the number of citations allowed in papers and employ descriptive metadata-rich citation styles that facilitate credit and discovery

Webometric analysis of departments of librarianship and information science: a follow-up study

This paper reports an analysis of the websites of UK departments of library and information science. Inlink counts of these websites revealed no statistically significant correlation with the quality of the research carried out by these departments, as quantified using departmental grades in the 2001 Research Assessment Exercise and citations in Google Scholar to publications submitted for that Exercise. Reasons for this lack of correlation include: difficulties in disambiguating departmental websites from larger institutional structures; the relatively small amount of research-related material in departmental websites; and limitations in the ways that current Web search engines process linkages to URLs. It is concluded that departmental-level webometric analyses do not at present provide an appropriate technique for evaluating academic research quality, and, more generally, that standards are needed for the formatting of URLs if inlinks are to become firmly established as a tool for website analysis