Pulsed laser deposition growth of Fe3O4 on III–V semiconductors for spin injection

We report on the growth of thin layers of Fe3O4 on GaAs and InAs by pulsed laser deposition. It is found that Fe3O4 grows epitaxially on InAs at a temperature of 350 °C. X-ray photoelecton spectroscopy (XPS) studies of the interface show little if any interface reaction resulting in a clean epitaxial interface. In contrast, Fe3O4 grows in columnar fashion on GaAs, oriented with respect to the growth direction but with random orientation in the plane of the substrate. In this case XPS analysis showed much more evidence of interface reactions, which may contribute to the random-in-plane growth

The most massive galaxies in clusters are already fully grown at z∼0.5z \sim 0.5

By constructing scaling relations for galaxies in the massive cluster MACSJ0717.5 at $z=0.545$ and comparing with those of Coma, we model the luminosity evolution of the stellar populations and the structural evolution of the galaxies. We calculate magnitudes, surface brightnesses and effective radii using HST/ACS images and velocity dispersions using Gemini/GMOS spectra, and present a catalogue of our measurements for 17 galaxies. We also generate photometric catalogues for $\sim 3000$ galaxies from the HST imaging. With these, we construct the colour-magnitude relation, the fundamental plane, the mass-to-light versus mass relation, the mass-size relation and the mass-velocity dispersion relation for both clusters. We present a new, coherent way of modelling these scaling relations simultaneously using a simple physical model in order to infer the evolution in luminosity, size and velocity dispersion as a function of redshift, and show that the data can be fully accounted for with this model. We find that (a) the evolution in size and velocity dispersion undergone by these galaxies between $z \sim 0.5$ and $z \sim 0$ is mild, with $R_e(z) \sim (1+z)^{-0.40\pm0.32}$ and $\sigma(z) \sim (1+z)^{0.09 \pm 0.27}$, and (b) the stellar populations are old, $\sim 10$ Gyr, with a $\sim 3$ Gyr dispersion in age, and are consistent with evolving purely passively since $z \sim 0.5$ with $\Delta \log M/L_B = -0.55_{-0.07}^{+0.15} z$. The implication is that these galaxies formed their stars early and subsequently grew dissipationlessly so as to have their mass already in place by $z \sim 0.5$, and suggests a dominant role for dry mergers, which may have accelerated the growth in these high-density cluster environments.Comment: 20 pages; accepted for publication in MNRA

Understanding the Different Phosphorus Indices in Nutrient Management Planning

Terminology in soil fertility and nutrient management Extension programming has evolved with increasing society emphasis on agriculture and environment interactions. Management of nutrient phosphorus (P) is important to agricultural environmental stewardship. Primarily, the term Phosphorus Index has two different meanings in nutrient management planning: the traditional use describes categories of plant response in soil test recommendations; the newer use describes a method of ascribing P movement risk in the landscape. Occasionally the term is used differently in soil science than these two examples. Extension personnel, agronomists, and technical personnel should use the appropriate terms to avoid confusing clientele

Meeting the Educational Needs of Professional Crop Advisers Using Extended Workshops

The International Certified Crop Adviser program has created a demand for continuing agronomic education for professional practitioners. An annual short course at Mississippi State University provides quality instruction in quantities sufficient for CCA registrants to maintain their professional registration. Faculty from the universities, industry, government, and concerned stakeholder entities provide diverse, up-to-the minute instruction for participants. Participants in the workshops indicate they appreciate the content, coordination, diversity, and logistics of the programming. This and similar workshops are becoming more widespread as the CCA program matures and local Extension Services refine their relationship with it

Professional Meetings: Planning and Performing Multiple Location Tours for Maximum Benefit and Impact

State, regional, national, and international meetings in agricultural and natural resource professions often include educational tours in or near the host city. Education improves if the tours are well-planned and executed. Contingency planning is integral to the process; plan for bad things to occur. Evaluation planning, implementation, and communication are tools for improving future professional meeting tours