Algebras stratified for all linear orders

In this paper we describe several characterizations of basic finite-dimensional $k$-algebras $A$ stratified for all linear orders, and classify their graded algebras as tensor algebras satisfying some extra property. We also discuss whether for a given preorder $\preccurlyeq$, $\mathcal{F} (_{\preccurlyeq} \Delta)$, the category of $A$-modules with $_{\preccurlyeq} \Delta$-filtrations, is closed under cokernels of monomorphisms, and classify quasi-hereditary algebras satisfying this property.Comment: Final version accepted by Alg. Repn. Theor

Spatial Bi-hourly Variation of Alternaria Spore Concentration in Worcester, UK

Alternaria species are ubiquitous fungi affecting food security and human health. They are pathogenic on many economically important crops and allergenic to many sensitive people worldwide. Studies from Worcester, UK have shown high a concentration of Alternaria spores, most likely caused by agricultural activities. However, it is unknown whether Alternaria spore concentrations vary geographically throughout Worcestershire. An investigation on the spatial variation in bi-hourly concentration of Alternaria spores in Worcestershire during 2016 and 2017 was conducted. Spores were sampled using two Hirst-type Burkard spore traps at the University of Worcester. One on the rooftop of a building at St John’s Campus and another at Lakeside Campus approximately 7 km away. St John’s Campus is located in the centre of Worcester (52.1970, -2.2421), while Lakeside Campus is located in an agricultural environment (52.2537, -2.2535) with regularly cut grass in the near surroundings. Slides were counted using bi-hourly traverse at x 400 magnification. The total number of spores per slide were converted to the daily mean of spores m¯³ of air. There was a highly positive correlation in the concentration of Alternaria spores between the two sites in both 2016 and 2017. St John’s had the highest peak of spore concentration (213 m¯³) in 2016 and Lakeside had the peak concentration in 2017 (184 m¯³). Concentrations above 100 m¯³ of air were observed more frequently at Lakeside. The study revealed that Alternaria spore concentrations were higher at Lakeside than at St John’s. This could be attributed to spores released from either crops or agricultural activities (e.g. haying or harvesting) or from decomposed grass since the surrounding area is routinely managed. Further work in 2018 will include spore correlations with weather variables from a pair of weather stations located at each site, enabling studies caused by variations in weather and climate. Spatial variation in bi-hourly spore concentrations is useful information to atopic subjects, health experts and crop pathologists. Keywords: Harvesting. Allergy. Fungal Spores

Searching for O2_2 in the SMC:Constraints on Oxygen Chemistry at Low Metallicities

We present a 39 h integration with the Odin satellite on the ground-state 118.75 GHz line of O2 towards the region of strongest molecular emission in the Small Magellanic Cloud. Our 3sigma upper limit to the O2 integrated intensity of <0.049 K km/s in a 9'(160 pc) diameter beam corresponds to an upper limit on the O2/H2 abundance ratio of <1.3E-6. Although a factor of 20 above the best limit on the O2 abundance obtained for a Galactic source, our result has interesting implications for understanding oxygen chemistry at sub-solar metal abundances. We compare our abundance limit to a variety of astrochemical models and find that, at low metallicities, the low O2 abundance is most likely produced by the effects of photo-dissociation on molecular cloud structure. Freeze-out of molecules onto dust grains may also be consistent with the observed abundance limit, although such models have not yet been run at sub-solar initial metallicities.Comment: 4 pages, accepted to A&A Letter

Aerobiology Meets Ecology: Development of Low-Cost Passive Gravitational Samplers

Access to proper and reliable research equipment is crucial in all natural science disciplines. This is especially true in biological research since experiments and observations require equipment that will show the same thing consistently. One method often utilized is called sampling, and it means collecting something by using a strict protocol. Our research is focused around sampling pollen and other biological particles from the air around us. If we want to sample particles in the air from locations where there is no electricity, the type of devices we can use limits us. This has led us to develop a sampler that does not require any electrical power; this technique is often referred to as passive sampling. We have created samplers with the design Sigma-2. It works by using a double wall and apertures with strategic placement to deflect the wind, and particles it carries, which then fall into a collection container within the sampler. In this poster we detail the construction, use and analysis using this passive sampler along with methods used to conduct quality control, to ensure that the results we acquire are reliable, replicable and comparable to other samplers

Engineering the Level Structure of a Giant Artificial Atom in Waveguide Quantum Electrodynamics

Engineering light-matter interactions at the quantum level has been central to the pursuit of quantum optics for decades. Traditionally, this has been done by coupling emitters, typically natural atoms and ions, to quantized electromagnetic fields in optical and microwave cavities. In these systems, the emitter is approximated as an idealized dipole, as its physical size is orders of magnitude smaller than the wavelength of light. Recently, artificial atoms made from superconducting circuits have enabled new frontiers in light-matter coupling, including the study of "giant" atoms which cannot be approximated as simple dipoles. Here, we explore a new implementation of a giant artificial atom, formed from a transmon qubit coupled to propagating microwaves at multiple points along an open transmission line. The nature of this coupling allows the qubit radiation field to interfere with itself leading to some striking giant-atom effects. For instance, we observe strong frequency-dependent couplings of the qubit energy levels to the electromagnetic modes of the transmission line. Combined with the ability to in situ tune the qubit energy levels, we show that we can modify the relative coupling rates of multiple qubit transitions by more than an order of magnitude. By doing so, we engineer a metastable excited state, allowing us to operate the giant transmon as an effective lambda system where we clearly demonstrate electromagnetically induced transparency.Comment: 12 pages, 8 figure

Neutron-proton interaction in rare-earth nuclei: Role of tensor force

We investigate the role of the tensor force in the description of doubly odd deformed nuclei within the framework of the particle-rotor model. We study the rare-earth nuclei 174Lu, 180Ta, 182Ta, and 188Re using a finite-range interaction, with and without tensor terms. Attention is focused on the lowest K=0 and K=1 bands, where the effects of the residual neutron-proton interaction are particularly evident. Comparison of the calculated results with experimental data evidences the importance of the tensor-force effects.Comment: 8 pages, 5 figures, to be published on Physical Review

Semiclassical theory of spin-orbit interactions using spin coherent states

We formulate a semiclassical theory for systems with spin-orbit interactions. Using spin coherent states, we start from the path integral in an extended phase space, formulate the classical dynamics of the coupled orbital and spin degrees of freedom, and calculate the ingredients of Gutzwiller's trace formula for the density of states. For a two-dimensional quantum dot with a spin-orbit interaction of Rashba type, we obtain satisfactory agreement with fully quantum-mechanical calculations. The mode-conversion problem, which arose in an earlier semiclassical approach, has hereby been overcome.Comment: LaTeX (RevTeX), 4 pages, 2 figures, accepted for Physical Review Letters; final version (v2) for publication with minor editorial change

Spatial Flowering Patterns in Dactylis glomerata Populations

Background: Dactylis glomerata is thought to be one of the major contributors to the annual grass pollen load in temperate regions due to wide distribution, high abundance and high pollen production. Detailed information about its flowering dynamics may therefore help in assessing the severity of the grass pollen season. Grass flora estimates of the flowering period are not enough to determine when the species is capable or most likely to release pollen. Observing multiple grass populations over time would enhance the detail and understanding of the flowering dynamics and reveal the variation in flowering events within a region. Methods: Eight populations were chosen in Worcestershire, UK in 2018, with minimum 150 individual tillers each to secure full variation within each population. Flowering progression was determined from the BBCH scale adapted from cereal monitoring. The phenology was focused on the percentage of extruded anthers, with equal intervals of 25, 50, 75 and 100%. Senescence was considered reached with the detachment of the last anther to avoid ambiguity in terms of pollen emission. The two main populations were observed every second day while the six secondary populations were observed ten times during the season. Results: A total of 2672 tillers were observed. The spatial investigation highlighted the uniformity of flowering progression between both main and secondary populations, with a mean seasonal difference of less than 1/10th of a phase. Both main populations started to flower on May 29th. The main populations reached peak flowering on June 14th while the average population reached full flowering on June 20th. Peak flowering is reached earlier than average full flowering in all populations due to the divergent growth progression of individual Dactylis tillers. The flowering ended on Aug 9th, 73 days later. Conclusion: This study highlights that Dactylis glomerata flowering is uniform over an entire region. There is little to no difference between populations in the timing of crucial flowering events such as start, peak and full flowering. It also notes the difference between peak and full flowering, which will be of importance in the aspect of pollen release

A spectral line survey of Orion KL in the bands 486-492 and 541-577 GHz with the Odin satellite I. The observational data

Spectral line surveys are useful since they allow identification of new molecules and new lines in uniformly calibrated data sets. Nonetheless, large portions of the sub-millimetre spectral regime remain unexplored due to severe absorptions by H2O and O2 in the terrestrial atmosphere. The purpose of the measurements presented here is to cover wavelength regions at and around 0.55 mm -- regions largely unobservable from the ground. Using the Odin astronomy/aeronomy satellite, we performed the first spectral survey of the Orion KL molecular cloud core in the bands 486--492 and 541--576 GHz with rather uniform sensitivity (22--25 mK baseline noise). Odin's 1.1 m size telescope, equipped with four cryo-cooled tuneable mixers connected to broad band spectrometers, was used in a satellite position-switching mode. Two mixers simultaneously observed different 1.1 GHz bands using frequency steps of 0.5 GHz (25 hours each). An on-source integration time of 20 hours was achieved for most bands. The entire campaign consumed ~1100 orbits, each containing one hour of serviceable astro-observation. We identified 280 spectral lines from 38 known interstellar molecules (including isotopologues) having intensities in the range 80 to 0.05 K. An additional 64 weak lines remain unidentified. Apart from the ground state rotational 1(1,0)--1(0,1) transitions of ortho-H2O, H218O and H217O, the high energy 6(2,4)--7(1,7) line of para-H2O and the HDO(2,0,2--1,1,1) line have been observed, as well as the 1,0--0,1 lines from NH3 and its rare isotopologue 15NH3. We suggest assignments for some unidentified features, notably the new interstellar molecules ND and SH-. Severe blends have been detected in the line wings of the H218O, H217O and 13CO lines changing the true linewidths of the outflow emission.Comment: 21 pages, 10 figures, 7 tables, accepeted for publication in Astronomy and Astrophysics 30 August 200

Isotopic ratios of H, C, N, O, and S in comets C/2012 F6 (Lemmon) and C/2014 Q2 (Lovejoy)

The apparition of bright comets C/2012 F6 (Lemmon) and C/2014 Q2 (Lovejoy) in March-April 2013 and January 2015, combined with the improved observational capabilities of submillimeter facilities, offered an opportunity to carry out sensitive compositional and isotopic studies of the volatiles in their coma. We observed comet Lovejoy with the IRAM 30m telescope between 13 and 26 January 2015, and with the Odin submillimeter space observatory on 29 January - 3 February 2015. We detected 22 molecules and several isotopologues. The H$_2^{16}$O and H$_2^{18}$O production rates measured with Odin follow a periodic pattern with a period of 0.94 days and an amplitude of ~25%. The inferred isotope ratios in comet Lovejoy are $^{16}$O/$^{18}$O = 499 $\pm$ 24 and D/H = 1.4 $\pm$ 0.4 $\times 10^{-4}$ in water, $^{32}$S/$^{34}$S = 24.7 $\pm$ 3.5 in CS, all compatible with terrestrial values. The ratio $^{12}$C/$^{13}$C = 109 $\pm$ 14 in HCN is marginally higher than terrestrial and $^{14}$N/$^{15}$N = 145 $\pm$ 12 in HCN is half the Earth ratio. Several upper limits for D/H or 12C/13C in other molecules are reported. From our observation of HDO in comet C/2014 Q2 (Lovejoy), we report the first D/H ratio in an Oort Cloud comet that is not larger than the terrestrial value. On the other hand, the observation of the same HDO line in the other Oort-cloud comet, C/2012 F6 (Lemmon), suggests a D/H value four times higher. Given the previous measurements of D/H in cometary water, this illustrates that a diversity in the D/H ratio and in the chemical composition, is present even within the same dynamical group of comets, suggesting that current dynamical groups contain comets formed at very different places or times in the early solar system.Comment: Accepted for publication in Astronomy and Astrophysic