Reconstructing Changes in Abundance of White-tailed Deer, Odocoileus virginianus, Moose, Alces alces, and Beaver, Castor canadensis, in Algonquin Park, Ontario, 1860-2004

The history of White-tailed Deer, Odocoileus virginianus, Moose, Alces alces, and Beaver, Castor canadensis, in Algonquin Park since the 1860s is reviewed and placed in the context of changes to the forest, weather, and parasitic disease. Deer seem to have been abundant in the late 1800s and early 1900s whereas Moose were also common but less so than deer. Deer declined through the 1920s as Moose probably increased. Deer had recovered by the 1940s when Moose seem to have been scarce. The deer population declined again in the 1960s, suffered major mortality in the early 1970s, and has never recovered; deer are essentially absent from the present day Algonquin landscape in winter. Moose increased steadily following the decline of deer and have numbered around 3500 since the mid-1980s. Beaver were scarce in the Park in the late 1800s but recovered by 1910 and appear to have been abundant through the early 1900s and at high numbers through mid-century. The Beaver population has, however, declined sharply since the mid-1970s. These changes can best be explained by the history of change to the structure and composition of the Park's forests. After extensive fire and logging in the late 1800s and early 1900s, the forest is now in an essentially mature state. Weather and parasitic disease, however, have also played a role. These three species form the prey base of Algonquin's Wolves, Canis lycaon, and the net decline of prey, especially deer, has important implications for the future of wolves in the Park

Multiparty Electoral Competition in the Netherlands and Germany: A Model Based on Multinomial Probit

A typical assumption of electoral models of party competition is that parties adopt policy positions so as to maximize expected vote share. Here we use Euro-barometer survey data and European elite-study data from 1979 for the Netherlands and Germany to construct a stochastic model of voter response, based on multinomial probit estimation. For each of these countries, we estimate a pure spatial electoral voting model and a joint spatial model. The latter model also includes individual voter and demographic characteristics. The pure spatial models for the two countries quite accurately described the electoral response as a stochastic function of party positions. We use these models to perform a thought experiment so as to estimate the expected vote maximizing party positions. We go on to propose a model of internal party decision-making based both on pre-election electoral estimation and postelection coalition bargaining. This model suggests why the various parties in the period in question did not adopt vote maximizing positions. We argue that maximizing expected vote will not, in general, be a rational party strategy in multiparty political systems which are based on proportional representation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/116246/1/pc98.pd

Adaptive Mesh Refinement Simulations of the Ionization Structure and Kinematics of Damped Lyα\alpha Systems with Self-consistent Radiative Transfer

We use high resolution Eulerian hydrodynamics simulations to study kinematic properties of the low ionization species in damped Ly-alpha systems at redshift z=3. Our adaptive mesh refinement simulations include most key ingredients relevant for modeling neutral gas in high-column density absorbers: hydrodynamics, gravitational collapse, continuum radiative transfer and gas chemistry, but no star formation. We model high-resolution Keck spectra with unsaturated low ion transitions in two Si II lines (1526 and 1808 A), and compare simulated line profiles to the data from the SDSS DLA survey. We find that with increasing grid resolution the models show a trend in convergence towards the observed distribution of HI column densities. While in our highest resolution model we recover the cumulative number of DLAs per unit absorption distance, none of our models predicts DLA velocity widths as high as indicated by the data, suggesting that feedback from star formation might be important. At z=3 a non-negligible fraction of DLAs with column densities below 10^21 cm^-2 is caused by tidal tails due to galaxy-galaxy interactions in more massive halo environments. Lower column density absorbers with N_HI < 10^21.4 cm^-2 are sensitive to changes in the UV background resulting in a 10% reduction of the cumulative number of DLAs for twice the quasar background relative to the fiducial value. We find that the mass cut-off below which a large fraction of dwarf galaxies cannot retain gas after reionization is 7*10^7 msun, lower than the previous estimates. Finally, we show that models with self-shielding commonly used in the literature produce significantly lower DLA velocity widths than the full radiative transfer runs.Comment: 13 pages, 11 figures, updated version, accepted to Ap

Influence of transport and ocean ice extent on biogenic aerosol sulfur in the Arctic atmosphere

The recent decline in sea ice cover in the Arctic Ocean could affect the regional radiative forcing via changes in sea ice-atmosphere exchange of dimethyl sulfide (DMS) and biogenic aerosols formed from its atmospheric oxidation, such as methanesulfonic acid (MSA). This study examines relationships between changes in total sea ice extent north of 70 degrees N and atmospheric MSA measurement at Alert, Nunavut, during 1980-2009; at Barrow, Alaska, during 1997-2008; and at Ny-Alesund, Svalbard, for 1991-2004. During the 1980-1989 and 1990-1997 periods, summer (July-August) and June MSA concentrations at Alert decreased. In general, MSA concentrations increased at all locations since 2000 with respect to 1990 values, specifically during June and summer at Alert and in summer at Barrow and Ny-Alesund. Our results show variability in MSA at all sites is related to changes in the source strengths of DMS, possibly linked to changes in sea ice extent as well as to changes in atmospheric transport patterns. Since 2000, a late spring increase in atmospheric MSA at the three sites coincides with the northward migration of the marginal ice edge zone where high DMS emissions from ocean to atmosphere have previously been reported. Significant negative correlations are found between sea ice extent and MSA concentrations at the three sites during the spring and June. These results suggest that a decrease in seasonal ice cover influencing other mechanisms of DMS production could lead to higher atmospheric MSA concentrations

Molecular recording of mammalian embryogenesis.

Ontogeny describes the emergence of complex multicellular organisms from single totipotent cells. This field is particularly challenging in mammals, owing to the indeterminate relationship between self-renewal and differentiation, variation in progenitor field sizes, and internal gestation in these animals. Here we present a flexible, high-information, multi-channel molecular recorder with a single-cell readout and apply it as an evolving lineage tracer to assemble mouse cell-fate maps from fertilization through gastrulation. By combining lineage information with single-cell RNA sequencing profiles, we recapitulate canonical developmental relationships between different tissue types and reveal the nearly complete transcriptional convergence of endodermal cells of extra-embryonic and embryonic origins. Finally, we apply our cell-fate maps to estimate the number of embryonic progenitor cells and their degree of asymmetric partitioning during specification. Our approach enables massively parallel, high-resolution recording of lineage and other information in mammalian systems, which will facilitate the construction of a quantitative framework for understanding developmental processes

The Abundance of Ornamental Corals After Mass Die Off in 1997 on the Padang Shelf Reef System, West Sumatera, Indonesia

The Indonesian Ministry of Marine Affairs and Fisheries aims to establish export quota ornamental corals based on scientifically-founded data from the natural environment. The purpose of this study was to determine the abundance of ornamental coral after mass die off in 1997. Ornamental corals were classified into three groups based on the guideline of ornamental coral propagation for trading purposes. Classification categories are rapid (3-6 months), middle (8-12 months), and slow growth rate (&gt;24 months), which relates to their harvesting time when transplanted for the trade purpose. The survey method used line intercept transects to get coral condition data and belt transect with 2 m width to get ornamental coral data. Both line and belt transect have 30 m length and with three replicates. The study showed number of colony and abundance of ornamental coral for fast growth rate group such as Acropora sp (1348 col &amp; 7.49 col/m2), Galaxea sp, Hydnophora exesa, H. microconus, Pocillopora damicornis, Stylopora sp and Montipora sp with the highest abundant found on Acropora sp and Montipora sp (1348 col &amp; 7.49 col/m2). Whereas the coral which from middle growth rate were Leptoseris sp, Pavona sp, Platygyra sp, Favia sp, Favites sp with the highest abundant found on Favia sp (101 col &amp; 0.56 col/m2). Coral species typically used for ornamental coral trade within the slow growth rate category such massive coral were not found on this survey. Due to the massive coral die-off in 1997 and the paucity of ornamental corals, the utilization of ornamental coral should be supported by coral transplantation and the broodstock of slow growth of coral taken from other area

The Recent Star Formation History of NGC 5102

We present Hubble Space Telescope photometry of young stars in NGC 5102, a nearby gas-rich post-starburst S0 galaxy with a bright young stellar nucleus. We use the IAC-pop/MinnIAC algorithm to derive the recent star formation history in three fields in the bulge and disk of NGC 5102. In the disk fields, the recent star formation rate has declined monotonically and is now barely detectable, but a starburst is still in progress in the bulge and has added about 2 percent to the mass of the bulge over the last 200 Myr. Other studies of star formation in NGC 5102 indicate that about 20 percent of its stellar mass was added over the past Gyr. If this is correct, then much of the stellar mass of the bulge may have formed over this period. It seems likely that this star formation was fueled by the accretion of a gas-rich system with HI mass of about 2 x 10^9 Msol which has now been almost completely converted into stars. The large mass of recently formed stars and the blue colours of the bulge suggest that the current starburst, which is now fading, may have made a significant contribution to build the bulge of NGC 5102.Comment: 36 pages, 16 figures, accepted in A

Evaluating the effectiveness of a preclinical practice of tooth preparation using digital training system:A randomised controlled trial

Purpose: This study aimed to evaluate the effectiveness of preclinical training on ceramic crown preparation using digital training system compared with traditional training method.Materials and methods: A sample of 66 participating fourth-year undergraduate dental students were randomly assigned to one of two groups for ceramic crown preparation: experimental group as trained using digital method with Online Peer-Review System (OPRS) and Real-time Dental Training and Evaluation System (RDTES); control group as trained using traditional method with instructor demonstration and evaluation. At the completion of training periods, both groups performed the preparation of ceramic crown of upper left central incisor, which were blindly scored by the experienced instructors under the pre-defined assessment criteria. The results of both were compared using Student's t-test or Wilcoxon signed rank test. The level of significance was P &lt; .05. The questionnaires regarding the benefits or drawbacks of digital training system were answered by the students of experimental group.Results: Five of 15 items in the assessment outcome of the digital group were significantly better than the traditional group. The questionnaire results from the students of the experimental group indicated 96.97% of the students agreed or strongly agreed that using digital training system could better improve the practical ability than traditional method. The total scores of practical results were significantly positively correlated with the points of the questionnaires.Conclusion: The digital training system with OPRS and RDTES might be a good alternative to the traditional training method in the preclinical course of dental practice.</p