6,324 research outputs found
Atypical Interstitial Pneumonia in the Bovine
On August 5, 1980, a dead 950 pound steer was submitted to the Iowa Veterinary Diagnostic Laboratory for necropsy (IVDL Case 18274). The history included acute dyspnea, raspy cough, a temperature of 40.5-41.7 C (105-107 F) in 20 out of 125 animals and two death.s These cattle had been purchased on July 17, 1980 and first noticed sick on August 4, 1980. The tentative diagnoses were Hemophilus pneumonia and viral pneumonia. Treatment included intravenous tetrayccline and intramuscular penicillin and resulted in a fairly good response
Ultrastable Optical Clock with Neutral Atoms in an Engineered Light Shift Trap
An ultrastable optical clock based on neutral atoms trapped in an optical
lattice is proposed. Complete control over the light shift is achieved by
employing the transition of
atoms as a "clock transition". Calculations of ac multipole polarizabilities
and dipole hyperpolarizabilities for the clock transition indicate that the
contribution of the higher-order light shifts can be reduced to less than 1
mHz, allowing for a projected accuracy of better than .Comment: 4 pages, 2 figures, accepted for publication in Phys. Rev. Let
Evidence for a breakdown of the Isobaric Multiplet Mass Equation: A study of the A=35, T=3/2 isospin quartet
Mass measurements on radionuclides along the potassium isotope chain have
been performed with the ISOLTRAP Penning trap mass spectrometer. For 35K
T1/2=178ms) to 46K (T1/2=105s) relative mass uncertainties of 2x10-8 and better
have been achieved. The accurate mass determination of 35K (dm=0.54keV) has
been exploited to test the Isobaric Multiplet Mass Equation (IMME) for the
A=35, T=3/2 isospinquartet. The experimental results indicate a deviation from
the generally adopted quadratic form.Comment: 8 pages, 4 figure
Revenue-driven scheduling in drone delivery networks with time-sensitive service level agreements
Drones are widely anticipated to be used for commercial service deliveries, with potential to contribute to economic growth, estimated at ÂŁ42 billion in the UK alone by the year 2030. Alongside air traffic control algorithms, drone-based courier services will have to make intelligent decisions about how to deploy their limited resources in order to increase profits. This paper presents a new scheduling algorithm for optimising the revenue of a drone courier service provider in these highly utilised time-sensitive service delivery systems. The first input to the algorithm is a monotonically decreasing value over time function which describes the service level agreement between the service provider and its customers. The second is the anticipated drone flight-time duration distribution. Our results show that the newly-developed scheduling algorithm, Least Lost Value, inspired by concepts for real-time computational workload processing, is able to successfully route drones to extract increased revenue to the service provider in comparison with two widely-used scheduling algorithms: First Come First Served and Shortest Job First, in terms of realised revenue
Reduction of Tc due to Impurities in Cuprate Superconductors
In order to explain how impurities affect the unconventional
superconductivity, we study non-magnetic impurity effect on the transition
temperature using on-site U Hubbard model within a fluctuation exchange (FLEX)
approximation. We find that in appearance, the reduction of Tc roughly
coincides with the well-known Abrikosov-Gor'kov formula. This coincidence
results from the cancellation between two effects; one is the reduction of
attractive force due to randomness, and another is the reduction of the damping
rate of quasi-particle arising from electron interaction. As another problem,
we also study impurity effect on underdoped cuprate as the system showing
pseudogap phenomena. To the aim, we adopt the pairing scenario for the
pseudogap and discuss how pseudogap phenomena affect the reduction of Tc by
impurities. We find that 'pseudogap breaking' by impurities plays the essential
role in underdoped cuprate and suppresses the Tc reduction due to the
superconducting (SC) fluctuation.Comment: 14 pages, 28 figures To be published in JPS
Event-based relaxation of continuous disordered systems
A computational approach is presented to obtain energy-minimized structures
in glassy materials. This approach, the activation-relaxation technique (ART),
achieves its efficiency by focusing on significant changes in the microscopic
structure (events). The application of ART is illustrated with two examples:
the structure of amorphous silicon, and the structure of Ni80P20, a metallic
glass.Comment: 4 pages, revtex, epsf.sty, 3 figure
Unusual T_c variation with hole concentration in Bi_2Sr_{2-x}La_xCuO_{6+\delta}
We have investigated the variation with the hole concentration in
the La-doped Bi 2201 system, BiSrLaCuO. It is
found that the Bi 2201 system does not follow the systematics in and
observed in other high- cuprate superconductors (HTSC's). The vs
characteristics are quite similar to what observed in Zn-doped HTSC's. An
exceptionally large residual resistivity component in the inplane resistivity
indicates that strong potential scatterers of charge carriers reside in CuO
planes and are responsible for the unusual variation with , as in the
Zn-doped systems. However, contrary to the Zn-doped HTSC's, the strong scatter
in the Bi 2201 system is possibly a vacancy in the Cu site.Comment: RevTeX, 3 figures, to be published in the Physical Review
Identification of potential HIV restriction factors by combining evolutionary genomic signatures with functional analyses.
BACKGROUND: Known antiretroviral restriction factors are encoded by genes that are under positive selection pressure, induced during HIV-1 infection, up-regulated by interferons, and/or interact with viral proteins. To identify potential novel restriction factors, we performed genome-wide scans for human genes sharing molecular and evolutionary signatures of known restriction factors and tested the anti-HIV-1 activity of the most promising candidates.
RESULTS: Our analyses identified 30 human genes that share characteristics of known restriction factors. Functional analyses of 27 of these candidates showed that over-expression of a strikingly high proportion of them significantly inhibited HIV-1 without causing cytotoxic effects. Five factors (APOL1, APOL6, CD164, TNFRSF10A, TNFRSF10D) suppressed infectious HIV-1 production in transfected 293T cells by >90% and six additional candidates (FCGR3A, CD3E, OAS1, GBP5, SPN, IFI16) achieved this when the virus was lacking intact accessory vpr, vpu and nef genes. Unexpectedly, over-expression of two factors (IL1A, SP110) significantly increased infectious HIV-1 production. Mechanistic studies suggest that the newly identified potential restriction factors act at different steps of the viral replication cycle, including proviral transcription and production of viral proteins. Finally, we confirmed that mRNA expression of most of these candidate restriction factors in primary CD4+ T cells is significantly increased by type I interferons.
CONCLUSIONS: A limited number of human genes share multiple characteristics of genes encoding for known restriction factors. Most of them display anti-retroviral activity in transient transfection assays and are expressed in primary CD4+ T cells
Isotope shift in the dielectronic recombination of three-electron ^{A}Nd^{57+}
Isotope shifts in dielectronic recombination spectra were studied for Li-like
^{A}Nd^{57+} ions with A=142 and A=150. From the displacement of resonance
positions energy shifts \delta E^{142,150}(2s-2p_1/2)= 40.2(3)(6) meV
(stat)(sys)) and \delta E^{142,150}(2s-2p_3/2) = 42.3(12)(20) meV of 2s-2p_j
transitions were deduced. An evaluation of these values within a full QED
treatment yields a change in the mean-square charge radius of ^{142,150}\delta
= -1.36(1)(3) fm^2. The approach is conceptually new and combines the
advantage of a simple atomic structure with high sensitivity to nuclear size.Comment: 10 pages, 3 figures, accepted for publication in Physical Review
Letter
Mass measurements of very neutron-deficient Mo and Tc isotopes and their impact on rp process nucleosynthesis
The masses of ten proton-rich nuclides, including the N=Z+1 nuclides 85-Mo
and 87-Tc, were measured with the Penning trap mass spectrometer SHIPTRAP.
Compared to the Atomic Mass Evaluation 2003 a systematic shift of the mass
surface by up to 1.6 MeV is observed causing significant abundance changes of
the ashes of astrophysical X-ray bursts. Surprisingly low alpha-separation
energies for neutron-deficient Mo and Tc are found, making the formation of a
ZrNb cycle in the rp process possible. Such a cycle would impose an upper
temperature limit for the synthesis of elements beyond Nb in the rp process.Comment: Link to online abstract:
http://link.aps.org/doi/10.1103/PhysRevLett.106.12250
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