The Born and Markov approximations for atom lasers

We discuss the use of the Born and Markov approximations in describing the dynamics of an atom laser. In particular, we investigate the applicability of the quantum optical Born-Markov master equation for describing output coupling. We derive conditions based on the atomic reservoir, and atom dispersion relations for when the Born-Markov approximations are valid and discuss parameter regimes where these approximations fail in our atom laser model. Differences between the standard optical laser model and the atom laser are due to a combination of factors, including the parameter regimes in which a typical atom laser would operate, the different reservoir state which is appropriate for atoms, and the different dispersion relations between atoms and photons. We present results based on an exact method in the regimes in which the Born-Markov approximation fails. The exact solutions in some experimentally relavent parameter regimes give non-exponential loss of atoms from a cavity.Comment: 10 pages, 3 figures. (2 new figues). Exact solutions have been included in section II. Sections IV and V have been expanded. A new section discussing the effects of gravity has been include

Prothonotary warbler nestling growth and condition inresponse to variation in aquatic and terrestrial preyavailability

Aquatic prey subsidies entering terrestrial habitats are well documented, but little is known about the degree to which these resources provide fitness benefits to riparian consumers. Riparian species take advantage of seasonal pulses of both terrestrial and aquatic prey, although aquatic resources are often over-looked in studies of how diet influences the reproductive ecology of these organisms. Ideally, the timing of resource pulses should occur at the time of highest reproductive demand. This study investigates the availability of aquatic(mayfly) and terrestrial (caterpillar) prey resources as well as the nestling diet of the prothonotary warbler (Protonotaria citrea) at two sites along the lower James River in Virginia during the 2014 breeding season. We found large differences in availability of prey items between the two sites, with one having significantly higher mayfly availability. Nestling diet was generally reflective of prey availability, and nestlings had faster mean growth rates at the site with higher aquatic prey availability. Terrestrial prey were fed more readily at the site with lower aquatic prey availability, and at this site, nestlings fed mayflies had higher mean growth rates than nestlings fed only terrestrial prey. Our results suggest that aquatic subsidies are an important resource for nestling birds and are crucial to understanding the breeding ecology of riparian species

The Export of an Algal Toxin into Terrestrial Predators via Emerging Aquatic Insects

Algal blooms are directly related to human-caused nutrient enrichment of water bodies. The cyanobacteria Microcystis aeruginosa produces microcystin (MC), a toxin that has been linked with mortalities and illness of many organisms. We show that MC is not constrained by the aquatic-terrestrial ecotone. MC was detected in a primary consumer and emerging aquatic invertebrate (Hexagenia Mayfly), a terrestrial insect and predator of emerging aquatic invertebrates (Tetragnathidae Spider), and a vertebrate consumer (Prothonotary Warbler). Mayfly and spider MC levels varied across the blooming period. MC levels in prothonotary warbler livers varied by age class; nestlings having the highest levels. MC levels decreased in fledglings over time. A more aquatic diet was related to higher MC levels in nestlings at one site and nestling fecal-sacs varied spatially, also indicating that aquatic diet is related to MC consumption. Warbler body condition and growth rate was not related to liver microcystin levels

The supercuspidal representations of p-adic classical groups

Let G be a unitary, symplectic or special orthogonal group over a locally compact non-archimedean local field of odd residual characteristic. We construct many new supercuspidal representations of G, and Bushnell-Kutzko types for these representations. Moreover, we prove that every irreducible supercuspidal representation of G arises from our constructions.Comment: 55 pages -- minor changes from 1st version (mostly in sections 2.2, 4.2 and 6.2). To appear in Inventiones mathematicae, 2008 (DOI is not yet active as at 12 Nov 2007

Gallium(III)-Promoted Halocyclizations of 1,6-Diynes

Adrian Landreth was an REU student, summer 2014Cyclization of 1,6-diynes promoted by stoichiometric Ga(III) halides produces vinyl halides in good to excellent yields. Under acidic conditions, initially formed iodocyclization products undergo in situ Friedel-Crafts cyclizations, giving access to iodo-indenopyridines. The application of the vinyl halides in cross-coupling reactions has been explored, and mechanistic aspects of the cyclization are discussed.HIGMS CMLD Initiative (P50 GM067041) NSF REU - Adrian Landreth support (CHE 1156666) NSF - NMR purchase (CHE 0619339) NSF - HRMS purchase (CHE0443618

The steady state quantum statistics of a non-Markovian atom laser

We present a fully quantum mechanical treatment of a single-mode atomic cavity with a pumping mechanism and an output coupling to a continuum of external modes. This system is a schematic description of an atom laser. In the dilute limit where atom-atom interactions are negligible, we have been able to solve this model without making the Born and Markov approximations. When coupling into free space, it is shown that for reasonable parameters there is a bound state which does not disperse, which means that there is no steady state. This bound state does not exist when gravity is included, and in that case the system reaches a steady state. We develop equations of motion for the two-time correlation in the presence of pumping and gravity in the output modes. We then calculate the steady-state output energy flux from the laser.Comment: 14 pages (twocloumn), 6 figure

Breast density classification with deep convolutional neural networks

Breast density classification is an essential part of breast cancer screening. Although a lot of prior work considered this problem as a task for learning algorithms, to our knowledge, all of them used small and not clinically realistic data both for training and evaluation of their models. In this work, we explore the limits of this task with a data set coming from over 200,000 breast cancer screening exams. We use this data to train and evaluate a strong convolutional neural network classifier. In a reader study, we find that our model can perform this task comparably to a human expert

PENGARUH WORD OF MOUTH TERHADAP KEPUTUSAN PEMBELIAN SMARTPHONE SAMSUNG

Penelitian ini bertujuan untuk mengetahui pengaruh dari Word Of Mouth keputusan pembelian Smartphone Samsung di Fakultas Ekonomi dan Bisnis Universitas Nusa Cendana. Penelitian ini merupakan penelitian survey yaitu penelitian yang mengumpulkan informasi dari responden menggunakan kuesioner. Populasi yang digunakan dalam penelitian ini merupakan mahasiswa pengguna smartphone Samsung di Fakultas Ekonomi dan Bisnis, Universitas Nusa Cendana. Teknik pengambilan sampel menggunakan proporsional random sampling sebanyak 96 responden. Teknik analisis data yang digunakan untuk menjawab hipotesis dalam penelitian ini adalah regresi linier sederhana.Hasil penelitian dengan tarif signifikan 5% menunjukkan bahwa Word Of Mouth berpengaruh signifikan terhadap keputusan pembelian konsumen, hal tersebut dibuktikan dengan  nilai signifikansi sebesar 0,000<0,05. Dari perhitungan koefisien determinasi didapatkan hasil bahwa R square bernilai 0,458 yang berarti Word Of Mouth mempengaruhi keputusan pembelian sebesar 45,80% sedangkan sisanya sebesar 54,20% dipengaruhi oleh variabel lain yang tidak diteliti dalam penelitian ini. Kata kunci : Word Of Mouth, Keputusan Pembelian