1,151 research outputs found
The cheese industry in Nebraska
The purpose of this study is twofold: (1) to investigate the evolving conditions in the dairy industry which have contributed to the reappearance of the cheese industry in Nebraska and (2) to examine the plants singly and to appraise them collectively as a viable new industry in the state
Collective excitations of atomic Bose-Einstein condensates
We apply linear-response analysis of the Gross-Pitaevskii equation to obtain
the excitation frequencies of a Bose-Einstein condensate confined in a
time-averaged orbiting potential trap. Our calculated values are in excellent
agreement with those observed in a recent experiment.Comment: 11 pages, 2 Postscript figures, uses psbox.tex for automatic figure
inclusion. More info at http://amo.phy.gasou.edu/bec.htm
Lifshitz-like transition and enhancement of correlations in a rotating bosonic ring lattice
We study the effects of rotation on one-dimensional ultra-cold bosons
confined to a ring lattice. For commensurate systems, at a critical value of
the rotation frequency, an infinitesimal interatomic interaction energy opens a
gap in the excitation spectrum, fragments the ground state into a macroscopic
superposition of two states with different circulation and generates a sudden
change in the topology of the momentum distribution. These features are
reminiscent of the topological changes in the Fermi surface that occurs in the
Lifshitz transition in fermionic systems. The entangled nature of the ground
state induces a strong enhancement of quantum correlations and decreases the
threshold for the Mott insulator transition. In contrast to the commensurate
case, the incommensurate lattice is rather insensitive to rotation. Our studies
demonstrate the utility of noise correlations as a tool for identifying new
physics in strongly correlated systems.Comment: 5 pages, 4 figure
Characterizing the Coherence of Bose-Einstein Condensates and Atom Lasers
For a dilute, interacting Bose gas of magnetically-trapped atoms at temperatures below the critical temperature T 0 for Bose-Einstein condensation, we determine the second-order coherence function g (2)(r 1, r 2) within the framework of a finite-temperature quantum field theory. We show that, because of the different spatial distributions of condensate and thermal atoms in the trap, g (2)(r 1, r 2) does not depend on |r 1 - r 2| alone. This means that the experimental determinations of g (2) reported to date give only its spatial average. Such an average may underestimate the degree of coherence attainable in an atom laser by judicious engineering of the output coupler
Steering the conversation: a linguistic exploration of natural language interactions with a digital assistant during simulated driving
Given the proliferation of ‘intelligent’ and ‘socially-aware’ digital assistants embodying everyday mobile technology – and the undeniable logic that utilising voice-activated controls and interfaces in cars reduces the visual and manual distraction of interacting with in-vehicle devices – it appears inevitable that next generation vehicles will be embodied by digital assistants and utilise spoken language as a method of interaction. From a design perspective, defining the language and interaction style that a digital driving assistant should adopt is contingent on the role that they play within the social fabric and context in which they are situated. We therefore conducted a qualitative, Wizard-of-Oz study to explore how drivers might interact linguistically with a natural language digital driving assistant. Twenty-five participants drove for 10 min in a medium-fidelity driving simulator while interacting with a state-of-the-art, high-functioning, conversational digital driving assistant. All exchanges were transcribed and analysed using recognised linguistic techniques, such as discourse and conversation analysis, normally reserved for interpersonal investigation. Language usage patterns demonstrate that interactions with the digital assistant were fundamentally social in nature, with participants affording the assistant equal social status and high-level cognitive processing capability. For example, participants were polite, actively controlled turn-taking during the conversation, and used back-channelling, fillers and hesitation, as they might in human communication. Furthermore, participants expected the digital assistant to understand and process complex requests mitigated with hedging words and expressions, and peppered with vague language and deictic references requiring shared contextual information and mutual understanding. Findings are presented in six themes which emerged during the analysis – formulating responses; turn-taking; back-channelling, fillers and hesitation; vague language; mitigating requests and politeness and praise. The results can be used to inform the design of future in-vehicle natural language systems, in particular to help manage the tension between designing for an engaging dialogue (important for technology acceptance) and designing for an effective dialogue (important to minimise distraction in a driving context)
Bogoliubov Approach to Superfluidity of Atoms in an Optical Lattice
We use the Bogoliubov theory of atoms in an optical lattice to study the approach to the Mott-insulator transition. We derive an explicit expression for the superfluid density based on the rigidity of the system under phase variations. This enables us to explore the connection between the quantum depletion of the condensate and the quasi-momentum distribution on the one hand and the superfluid fraction on the other. The approach to the insulator phase may be characterized through the filling of the band by quantum depletion, which should be directly observable via the matter–wave interference patterns. We complement these findings by self-consistent Hartree–Fock–Bogoliubov–Popov calculations for one-dimensional lattices, including the effects of a parabolic trapping potential
Progress toward curing HIV infection with hematopoietic cell transplantation.
HIV-1 infection afflicts more than 35 million people worldwide, according to 2014 estimates from the World Health Organization. For those individuals who have access to antiretroviral therapy, these drugs can effectively suppress, but not cure, HIV-1 infection. Indeed, the only documented case for an HIV/AIDS cure was a patient with HIV-1 and acute myeloid leukemia who received allogeneic hematopoietic cell transplantation (HCT) from a graft that carried the HIV-resistant CCR5-∆32/∆32 mutation. Other attempts to establish a cure for HIV/AIDS using HCT in patients with HIV-1 and malignancy have yielded mixed results, as encouraging evidence for virus eradication in a few cases has been offset by poor clinical outcomes due to the underlying cancer or other complications. Such clinical strategies have relied on HIV-resistant hematopoietic stem and progenitor cells that harbor the natural CCR5-∆32/∆32 mutation or that have been genetically modified for HIV-resistance. Nevertheless, HCT with HIV-resistant cord blood remains a promising option, particularly with inventories of CCR5-∆32/∆32 units or with genetically modified, human leukocyte antigen-matched cord blood
LOFAR discovery of the fastest-spinning millisecond pulsar in the Galactic field
We report the discovery of PSR J09520607, a 707-Hz binary millisecond
pulsar which is now the fastest-spinning neutron star known in the Galactic
field (i.e., outside of a globular cluster). PSR J09520607 was found using
LOFAR at a central observing frequency of 135 MHz, well below the 300 MHz to 3
GHz frequencies typically used in pulsar searches. The discovery is part of an
ongoing LOFAR survey targeting unassociated Fermi Large Area Telescope
-ray sources. PSR J09520607 is in a 6.42-hr orbit around a very
low-mass companion ( M) and we identify a
strongly variable optical source, modulated at the orbital period of the
pulsar, as the binary companion. The light curve of the companion varies by 1.6
mag from at maximum to , indicating that it is
irradiated by the pulsar wind. Swift observations place a 3- upper
limit on the keV X-ray luminosity of erg
s (using the 0.97 kpc distance inferred from the dispersion measure).
Though no eclipses of the radio pulsar are observed, the properties of the
system classify it as a black widow binary. The radio pulsed spectrum of PSR
J09520607, as determined through flux density measurements at 150 and 350
MHz, is extremely steep with (where ).
We discuss the growing evidence that the fastest-spinning radio pulsars have
exceptionally steep radio spectra, as well as the prospects for finding more
sources like PSR J09520607.Comment: 9 pages, 3 figures, 1 table, published in ApJ letter
Changing the Principal Supervisor Role to Better Support Principals: Evidence from the Principal Supervisor Initiative
The principal supervisor job has traditionally revolved around administration, operations and compliance, but as principals have increasingly been called on in recent years to concentrate on supporting high-quality teaching, the idea of a complementary makeover of the supervisor job has gained attention. In 2014, with funding from The Wallace Foundation, six large school districts around the country embarked on a four-year, $24-million initiative to redesign the supervisor position so it focused primarily on supporting principals in their role as instructional leaders.This report, which looks at the final year and the effects of the Principal Supervisor Initiative, concludes that the effort succeeded in changing the job so that it centered on developing and evaluating principals to help them promote effective teaching and learning in their schools. Over the course of the initiative, principals' ratings of their supervisors' effectiveness rose from 3.88 to 4.10 on a scale of 1-to-5, a statistically significant increase. Principals reported greater frequency of supervisor practices to develop school leadership—such as helping principals with data analysis, providing them with useful feedback and working with them to assess teacher effectiveness
Defining The Dose Of Gemtuzumab Ozogamicin In Combination With Induction Chemotherapy In Acute Myeloid Leukemia: A Comparison Of 3 Mg/M2 With 6 Mg/M2 In The NCRI AML17 Trial
Arecent source data meta-analysis of randomized trials in adults assessing the immunoconjugate gemtuzumab ozogamicin combined with standard chemotherapy in acute myeloid leukemia showed a significant survival benefit in patients without an adverse karyotype. It is not clear whether the optimal dose should be 3 mg/m2 or 6 mg/m2. In this study, we randomized 788 patients to a single dose of gemtuzumab ozogamicin 3 mg/m2 or 6 mg/m2 with the first course of induction therapy. We found that the rate of complete remission was higher with 3 mg/m2 [82% vs. 76%; odds ratio 1.46 (1.04–2.06); P=0.03], but this was balanced by a higher rate of complete remission with incomplete peripheral blood count recovery in the 6 mg/m2 treatment (10% vs. 7%) resulting in similar overall response rate [89% vs. 86%; hazard ratio 1.34 (0.88–2.04); P=0.17]. There was no overall difference in relapse or survival at four years between the arms: 46% vs. 54%; hazard ratio 1.17 (0.94–1.45), P=0.5, and 50% versus 47%; hazard ratio 1.10 (0.90–1.34), P=0.3, respectively. The 30- and 60-day mortality was significantly higher in the 6 mg/m2 recipients: 7% versus 3%; hazard ratio 2.07 (1.11–3.87), P=0.02, and 9% versus 5%; hazard ratio 1.99 (1.17–3.39), P=0.01, respectively, which in addition was associated with a higher rate of veno-occlusive disease (5.6% vs. 0.5%; P<0.0001). Our conclusion from this trial is that there is no advantage in using a single dose of 6 mg/m2 of gemtuzumab ozogamicin in combination with induction chemotherapy when compared with a 3 mg/m2 dose, with respect to response, disease-free and overall survival, either overall, or in any disease subgroup. (AML17 was registered as ISRCTN55675535.
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