Notes on the Diatom Cylindrotheca gracilis (Breh. ex Kutz) Grun: Its Ecology and Distribution

The diatom Cylindrotheca gracilis (Breb. ex Kutz) Grun., considered by some as a Brackish water species, was found as a massive growth in isolated pools along Dugout Creek, Dickinson County, Iowa. Chemical analyses show the water to be high in S04, Mg., Ca., and low in Cl ions. Comparative data from other waters in the United States containing this species shows similar pattern of high conductivity suggesting that factors other than chlorides might be more critical for growth. United States distribution for this diatom includes: Maryland (brackish water), Ohio (fresh water) and Iowa (fresh water)

‘X Journalism’. Exploring journalism’s diverse meanings through the names we give it

In this article we propose the notion of X Journalism as an observational tool and concept. It owes its existence to a simple observation: the evolution of journalism is accompanied by the emergence of ever-new journalism-related terms, i.e. combinations of the word ‘journalism’ with a particular modifying term that represents and signals a certain specificity and novelty. Examples include ‘robot journalism’, ‘foundation- funded journalism’, ‘cross-border journalism’, or ‘solutions journalism’ – just to name a few. To date, we have collected and mapped 166 X journalisms and have ‘crowd- categorized’ them into clusters according to the different aspects they refer to. We explore X Journalism as a concept, present our mapping, and show how it can help to cope with journalism’s increasing complexity, grasp the diversity of the field, trace its constant evolution, as well as identify patterns and interrelations between these different movements and occurrences. Through a test case of audience-related X journalisms we demonstrate an empirical application before illustrating the theoretical compatibility of X Journalism and suggesting a research agenda that highlights potentials for X Journalism-driven studies.<br/

Tuning the exciton g-factor in single InAs/InP quantum dots

Photoluminescence data from single, self-assembled InAs/InP quantum dots in magnetic fields up to 7 T are presented. Exciton g-factors are obtained for dots of varying height, corresponding to ground state emission energies ranging from 780 meV to 1100 meV. A monotonic increase of the g-factor from -2 to +1.2 is observed as the dot height decreases. The trend is well reproduced by sp3 tight binding calculations, which show that the hole g-factor is sensitive to confinement effects through orbital angular momentum mixing between the light-hole and heavy-hole valence bands. We demonstrate tunability of the exciton g-factor by manipulating the quantum dot dimensions using pyramidal InP nanotemplates

Fermi-LAT Observations of High- and Intermediate-Velocity Clouds: Tracing Cosmic Rays in the Halo of the Milky Way

It is widely accepted that cosmic rays (CRs) up to at least PeV energies are Galactic in origin. Accelerated particles are injected into the interstellar medium where they propagate to the farthest reaches of the Milky Way, including a surrounding halo. The composition of CRs coming to the solar system can be measured directly and has been used to infer the details of CR propagation that are extrapolated to the whole Galaxy. In contrast, indirect methods, such as observations of gamma-ray emission from CR interactions with interstellar gas, have been employed to directly probe the CR densities in distant locations throughout the Galactic plane. In this article we use 73 months of data from the Fermi Large Area Telescope in the energy range between 300 MeV and 10 GeV to search for gamma-ray emission produced by CR interactions in several high- and intermediate-velocity clouds located at up to ~ 7 kpc above the Galactic plane. We achieve the first detection of intermediate-velocity clouds in gamma rays and set upper limits on the emission from the remaining targets, thereby tracing the distribution of CR nuclei in the halo for the first time. We find that the gamma-ray emissivity per H atom decreases with increasing distance from the plane at 97.5% confidence level. This corroborates the notion that CRs at the relevant energies originate in the Galactic disk. The emissivity of the upper intermediate-velocity Arch hints at a 50% decline of CR densities within 2 kpc from the plane. We compare our results to predictions of CR propagation models.Comment: Accepted for publication in the Astrophysical Journa

A measurement of cosmic ray deuterium from 0.5–2.9 GeV/nucleon

The rare isotopes ^(2)H and ^(3)He in cosmic rays are believed to originate mainly from the interaction of high energy protons and helium with the galactic interstellar medium. The unique propagation history of these rare isotopes provides important constraints on galactic cosmic ray source spectra and on models for their propagation within the Galaxy. Hydrogen and helium isotopes were measured with the balloon-borne experiment, IMAX, which flew from Lynn Lake, Manitoba in 1992. The energy spectrum of deuterium between 0.5 and 3.2 GeV/nucleon measured by the IMAX experiment as well as previously published results of ^(3)He from the same instrument will be compared with predictions of cosmic ray galactic propagation models. The observed composition of the light isotopes is found to be generally consistent with the predictions of the standard Leaky Box Model derived to fit observations of heavier nucle

Preliminary results of fast neutron treatments in carcinoma of the pancreas

A group of 30 patients with adenocarcinoma of the pancreas including some patients with very advanced disease, were treated with the so-called mixed beam modality employing photon treatments three times per week and neutron treatments twice a week. Two hundred Rads or equivalent Rads (RBE 3.3) were given in daily fractions aiming at a total dose of 6000 Rads in 6 to 8 weeks. The treatments were well tolerated and significant palliation was achieved in 26 to 30 cases. Twelve months survival was 33 percent with a median survival of 7 months or 210 days. Treatment techniques and localization procedures are discussed

Fermi-LAT limits on the γ-ray opacity of the Universe

The Fermi Large Area Telescope (LAT) has provided us with a rich sample of extragalactic sources, among which γ-ray blazars with redshift up to z ∼ 3 and Gamma-Ray Bursts with redshift up to z ∼ 4.3, that we have used to probe the interaction via pair production of γ-ray photons above 10GeV with low-energy photons from the Extragalactic Background Light (EBL). The EBL from the infrared to the ultraviolet is difficult to measure directly, but can be constrained with a variety of methods. In this paper we report the method applied to evaluate the EBL attenuation of γ-ray fluxes by comparing the measured energy spectrum of the source and the unabsorbed spectrum above 10 GeV. We place upper limits on the γ-ray opacity of the Universe at various energies and redshifts, and compare this with predictions from well-known EBL models. We find that EBL intensities at optical-UV wavelengths as large as those predicted by the “baseline” and “fast evolution” models can be ruled out with high confidence. The ensuing upper limits to the EBL opacity are presented

Phase Transitions in Operational Risk

In this paper we explore the functional correlation approach to operational risk. We consider networks with heterogeneous a-priori conditional and unconditional failure probability. In the limit of sparse connectivity, self-consistent expressions for the dynamical evolution of order parameters are obtained. Under equilibrium conditions, expressions for the stationary states are also obtained. The consequences of the analytical theory developed are analyzed using phase diagrams. We find co-existence of operational and non-operational phases, much as in liquid-gas systems. Such systems are susceptible to discontinuous phase transitions from the operational to non-operational phase via catastrophic breakdown. We find this feature to be robust against variation of the microscopic modelling assumptions.Comment: 13 pages, 7 figures. Accepted in Physical Review