Full-wave electromagnetic modes and hybridization in nanoparticle dimers

The plasmon hybridization theory is based on a quasi-electrostatic approximation of the Maxwell’s equations. It does not take into account magnetic interactions, retardation effects, and radiation losses. Magnetic interactions play a dominant role in the scattering from dielectric nanoparticles. The retardation effects play a fundamental role in the coupling of the modes with the incident radiation and in determining their radiative strength; their exclusion may lead to erroneous predictions of the excited modes and of the scattered power spectra. Radiation losses may lead to a significant broadening of the scattering resonances. We propose a hybridization theory for non-Hermitian composite systems based on the full-Maxwell equations that, overcoming all the limitations of the plasmon hybridization theory, unlocks the description of dielectric dimers. As an example, we decompose the scattered field from silicon and silver dimers, under different excitation conditions and gap-sizes, in terms of dimer modes, pinpointing the hybridizing isolated-sphere modes behind them

Bloodstream yeast infections: a 15-month survey

A 15-month survey of 412 bloodstream yeast isolates from 54 Belgian hospitals was undertaken. Candida albicans was the most common species (47.3%) followed by C. glabrata (25.7%), C. parapsilosis (8.0%), C. tropicalis (6.8%) and Saccharomyces cerevisiae (5.1%). Common predisposing factors were antibacterial therapy (45%), hospitalization in intensive care units (34%), presence of in-dwelling catheters (32%), underlying cancer (23%) and major surgery (11%). Most patients had more than one predisposing factor. Fluconazole alone or in combination with another antifungal agent was the treatment of choice for 86.6% of the cases. Susceptibility testing revealed that 93.5% were susceptible to amphotericin B, 39.6% to itraconazole, 42.8% to fluconazole and 87% to voriconazole. Resistance to azoles was more common among C. glabrata isolates

Dose of colistin. a work in progress?

We thank Rashid and colleagues [1] and Honoré and colleagues [2] for their comments regarding our article on risk factors for acute kidney injury in pa- tients receiving colistin or other nephrotoxic antimi- crobials [3]. It is correct that we did not specifically report urine output in the text, but it was obviously included in the RIFLE (Risk, Injury, Failure, Loss of kidney function, and End-stage kidney disease) criteria reported in Table two [3]

Evolutionary neurocontrol: A novel method for low-thrust gravity-assist trajectory optimization

This article discusses evolutionary neurocontrol, a novel method for low-thrust gravity-assist trajectory optimization

Strata, Soma, Psyche: Narrative and the Imagination in the Nineteenth-Century Science of Lyell, Darwin, and Freud

My dissertation, “Strata, Soma, Psyche: Narrative and the Imagination in the Nineteenth-Century Science of Lyell, Darwin, and Freud,” contributes new research to the diverse field mapping the intersections of science and literature in the nineteenth century. Although scholars such as Gillian Beer and George Levine have established ties between developments in the natural sciences and the scope of the nineteenth-century novel, there has not been a sustained effort to attend to the narrative structures of the primary texts that most influenced coterminous literary movements of the period. My work thus attends closely to the narrative and imaginative form of scientific writing that attempts to transcend the limits of what can be seen. All three of Charles Lyell’s, Charles Darwin’s, and Sigmund Freud’s discipline-making texts (The Principles of Geology, The Origin of Species, and The Interpretation of Dreams) deal with historical forces whose operations cannot be observed in action, but only through the traces that are left behind. Three long single-author chapters detail how each text reconciles the ambition to establish a new branch of empirical science with the necessity of relying on the imagination to ford the gaps in physical evidence. I provide close readings of these foundational texts, identifying in each the rhetorical systems by which it represents and details what has never been present, and I demonstrate how each author strategically employs methods more conventionally associated with fictional narratives in the pursuit of establishing scientific facts. As a result, my project reframes the dominant concerns of Nineteenth-Century Literature and Science Studies by focusing in on how literary point of view, diversely defined, enables scientific thought to find a language in which to speak

The Metallicity Distribution Function of Field Stars in M31's Bulge

We have used Hubble Space Telescope Wide Field Planetary Camera 2 observations to construct a color-magnitude diagram (CMD) for the bulge of M31 at a location ~1.6 kpc from the galaxy's center. Using scaled-solar abundance theoretical red giant branches with a range of metallicities, we have translated the observed colors of the stars in the CMD to abundances and constructed a metallicity distribution function (MDF) for this region. The MDF shows a peak at [M/H]~0 with a steep decline at higher metallicities and a more gradual tail to lower metallicities. This is similar in shape to the MDF of the Milky Way bulge but shifted to higher metallicities by ~0.1 dex. As is the case with the Milky Way bulge MDF, a pure closed box model of chemical evolution, even with significant pre-enrichment, appears to be inconsistent with the M31 bulge MDF. However, a scenario in which an initial infall of gas enriched the bulge to an abundance of [M/H] ~ -1.6 with subsequent evolution proceeding as a closed box provides a better fit to the observed MDF. The similarity between the MDF of the M31 bulge and that of the Milky Way stands in stark contrast to the significant differences in the MDFs of their halo populations. This suggests that the bulk of the stars in the bulges of both galaxies were in place before the accretion events that occurred in the halos could influence them.Comment: 12 pages, 9 figures, accepted for publication in The Astronomical Journal, October 200

[OIII] Emission and Gas Kinematics in a Lyman-alpha Blob at z ~ 3.1

We present spectroscopic measurements of the [OIII] emission line from two subregions of strong Lyman-alpha emission in a radio-quiet Lyman-alpha blob (LAB). The blob under study is LAB1 (Steidel et al. 2000) at z ~ 3.1, and the [OIII] detections are from the two Lyman break galaxies embedded in the blob halo. The [OIII] measurements were made with LUCIFER on the 8.4m Large Binocular Telescope and NIRSPEC on 10m Keck Telescope. Comparing the redshift of the [OIII] measurements to Lyman-alpha redshifts from SAURON (Weijmans et al. 2010) allows us to take a step towards understanding the kinematics of the gas in the blob. Using both LUCIFER and NIRSPEC we find velocity offsets between the [OIII] and Lyman-alpha redshifts that are modestly negative or consistent with 0 km/s in both subregions studied (ranging from -72 +/- 42 -- +6 +/- 33 km/s). A negative offset means Lyman-alpha is blueshifted with respect to [OIII], a positive offset then implies Lyman-alpha is redshifted with respect to [OIII]. These results may imply that outflows are not primarily responsible for Lyman alpha escape in this LAB, since outflows are generally expected to produce a positive velocity offset (McLinden et al. 2011). In addition, we present an [OIII] line flux upper limit on a third region of LAB1, a region that is unassociated with any underlying galaxy. We find that the [OIII] upper limit from the galaxy-unassociated region of the blob is at least 1.4 -- 2.5 times fainter than the [OIII] flux from one of the LBG-associated regions and has an [OIII] to Lyman-alpha ratio measured at least 1.9 -- 3.4 times smaller than the same ratio measured from one of the LBGs.Comment: submitted to Ap