Tarski monoids: Matui's spatial realization theorem

We introduce a class of inverse monoids, called Tarski monoids, that can be regarded as non-commutative generalizations of the unique countable, atomless Boolean algebra. These inverse monoids are related to a class of etale topological groupoids under a non-commutative generalization of classical Stone duality and, significantly, they arise naturally in the theory of dynamical systems as developed by Matui. We are thereby able to reinterpret a theorem of Matui on a class of \'etale groupoids as an equivalent theorem about a class of Tarski monoids: two simple Tarski monoids are isomorphic if and only if their groups of units are isomorphic. The inverse monoids in question may also be viewed as countably infinite generalizations of finite symmetric inverse monoids. Their groups of units therefore generalize the finite symmetric groups and include amongst their number the classical Thompson groups.Comment: arXiv admin note: text overlap with arXiv:1407.147

The Genome and Methylome of a Subsocial Small Carpenter Bee, Ceratina calcarata

Understanding the evolution of animal societies, considered to be a major transition in evolution, is a key topic in evolutionary biology. Recently, new gateways for understanding social evolution have opened up due to advances in genomics, allowing for unprecedented opportunities in studying social behavior on a molecular level. In particular, highly eusocial insect species (caste-containing societies with nonreproductives that care for siblings) have taken center stage in studies of the molecular evolution of sociality. Despite advances in genomic studies of both solitary and eusocial insects, we still lack genomic resources for early insect societies. To study the genetic basis of social traits requires comparison of genomes from a diversity of organisms ranging from solitary to complex social forms. Here we present the genome of a subsocial bee, Ceratina calcarata. This study begins to address the types of genomic changes associated with the earliest origins of simple sociality using the small carpenter bee. Genes associated with lipid transport and DNA recombination have undergone positive selection in C. calcarata relative to other bee lineages. Furthermore, we provide the first methylome of a noneusocial bee. Ceratina calcarata contains the complete enzymatic toolkit for DNA methylation. As in the honey bee and many other holometabolous insects, DNA methylation is targeted to exons. The addition of this genome allows for new lines of research into the genetic and epigenetic precursors to complex social behaviors

ESR studies of the slow tumbling of vanadyl spin probes in nematic liquid crystals

ESR line shapes that are appropriate for slowly tumbling vanadyl spin probes in viscous nematic liquid crystals were calculated by the stochastic Liouville method. Because of the symmetry possessed by vanadyl, the analysis and interpretation of these line shapes was simplified considerably. Spectral line shapes agreed well with experimental spectra of VOAcAc in the nematic liquid crystal Phase V and BEPC. Deviations from Brownian rotational diffusion were noted. A slowly fluctuating torque analysis yielded good agreement with the experimental spectra

Body size changes in passerine birds introduced to New Zealand from the UK

One feature of global geographic variation in avian body sizes is that they are larger on isolated islands than on continental regions. Therefore, this study aims to assess whether there have been changes in body size following successful establishment for seven passerine bird species (blackbird Turdus merula, song thrush T. philomelos, house sparrow Passer domesticus, chaffinch Fringilla coelebs, greenfinch Chloris chloris, goldfinch Carduelis carduelis, yellowhammer Emberiza citrinella) introduced from the continental islands of the UK to the more isolated oceanic landmass of New Zealand in the middle of the nineteenth century. Measures of tarsus length were taken from individuals from contemporary UK and New Zealand populations of these species, and from historical specimens collected around the time that individuals were translocated from the UK to New Zealand. Analysis of Variance was used to test for size differences between contemporary UK and New Zealand populations, and between historical UK and contemporary UK and New Zealand populations. Historical UK populations have longer tarsi, on average, than 12 (7 UK and 5 New Zealand) of the 14 contemporary populations. Significant decreases in tarsus length relative to the historical populations have occurred in the UK for blackbird, chaffinch and greenfinch, and in the New Zealand blackbird population. Contemporary New Zealand house sparrows have significantly longer tarsi, on average, than both historical and contemporary UK populations. Exposure to novel environments may be expected to lead to changes in the morphology and other traits of exotic species, but changes have also occurred in the native range. In fact, contrary to expectations, the most common differences we found were between contemporary and historical UK populations. Consideration of contemporary populations alone would underestimate the true scale of morphological change in these species over time, which may be due to phenotypic plasticity or genetic adaptation to environmental changes experienced by all populations in the last 150 years

High power operation of an X-band gyrotwistron

We report the first experimental verification of a gyrotwistron amplifier. The device utilized a single 9.858 GHz, TE011 cavity, a heavily attenuated drift tube, and a long tapered output waveguide section. With a 440 kV, 200-245 A, 1 μs electron beam and a sharply tapered axial magnetic field, peak powers above 21 MW were achieved with a gain near 24 dB. Performance was limited by competition from a fundamental TE11 mode. A multimode code was developed to analyze this system, and simulations were in good agreement with the experiment

Nighttime air quality under desert conditions

Nighttime concentrations of the gas phase nitrate radical (NO3) were successfully measured during a four week field campaign in an arid urban location, Reno Nevada, using long-path Differential Optical Absorbance Spectrometry (DOAS). While typical concentrations of NO3 ranged from 5 to 20ppt, elevated concentrations were observed during a wildfire event. Horizontal mixing in the free troposphere was considerable because the sampling site was above the stable nocturnal boundary layer every night and this justified a box modeling approach. Process analysis of box model simulations showed NO3 accounted for approximately half of the loss of internal olefins, 60% of the isoprene loss, and 85% of the α-pinene loss during the nighttime hours during a typical night of the field study. The NO3+aldehyde reactions were not as important as anticipated. On a polluted night impacted by wildfires upwind of the sampling location, NO3 reactions were more important. Model simulations overpredicted NO2 concentrations for both case studies and inorganic chemistry was the biggest influence on NO3 concentrations and on nitric acid formation. The overprediction may be due to additional NO2 loss processes that were not included in the box model, as deposition and N2O5 uptake had no significant effect on NO2 levels

Nature-Inspired Interconnects for Self-Assembled Large-Scale Network-on-Chip Designs

Future nano-scale electronics built up from an Avogadro number of components needs efficient, highly scalable, and robust means of communication in order to be competitive with traditional silicon approaches. In recent years, the Networks-on-Chip (NoC) paradigm emerged as a promising solution to interconnect challenges in silicon-based electronics. Current NoC architectures are either highly regular or fully customized, both of which represent implausible assumptions for emerging bottom-up self-assembled molecular electronics that are generally assumed to have a high degree of irregularity and imperfection. Here, we pragmatically and experimentally investigate important design trade-offs and properties of an irregular, abstract, yet physically plausible 3D small-world interconnect fabric that is inspired by modern network-on-chip paradigms. We vary the framework's key parameters, such as the connectivity, the number of switch nodes, the distribution of long- versus short-range connections, and measure the network's relevant communication characteristics. We further explore the robustness against link failures and the ability and efficiency to solve a simple toy problem, the synchronization task. The results confirm that (1) computation in irregular assemblies is a promising and disruptive computing paradigm for self-assembled nano-scale electronics and (2) that 3D small-world interconnect fabrics with a power-law decaying distribution of shortcut lengths are physically plausible and have major advantages over local 2D and 3D regular topologies

Variability in the extreme helium star LSS 5121

We report a photometric and spectroscopic study of the hot extreme helium star LSS 5121. We found photometric variability, but no period was evident in its periodogram. This is consistent with the previous proposal, based on spectral line variations, that LSS 5121 is a non-radial pulsator similar to other hot extreme helium stars.Comment: 5 pages, 6 figure