Scalar and vector form factors of the in-medium nucleon

Using the quark-meson coupling model, we calculate the form factors at sigma- and omega-nucleon strong-interaction vertices in nuclear matter. The Peierls-Yoccoz projection technique is used to take account of center of mass and recoil corrections. We also apply the Lorentz contraction to the internal quark wave function. The form factors are reduced by the nuclear medium relative to those in vacuum. At normal nuclear matter density and Q^2 = 1 GeV^2, the reduction rate in the scalar form factor is about 15%, which is almost identical to that in the vector one. We parameterize the ratios of the form factors in symmetric nuclear matter to those in vacuum as a function of nuclear density and momentum transfer.Comment: 13 pages, 2 figures, references are up date

Effectively Conducting Field Days While Responding to Unprecedented External Restrictions

Despite external influences such as societal restrictions imposed during the 2020 COVID-19 pandemic, farmers continue to work, and needs for outreach and education have not waned. Extension professionals must continue to support these needs by using media and channels not typically employed when more traditional vehicles, such as on-site consultations and field days, are not practical or safe. The Iowa Learning Farms team from Iowa State University Outreach and Extension has developed a successful Virtual Field Day program using available online tools that can be easily adopted by other Extension organizations to facilitate outreach

Switching of +/-360deg domain wall states in a nanoring by an azimuthal Oersted field

We demonstrate magnetic switching between two $360^\circ$ domain wall vortex states in cobalt nanorings, which are candidate magnetic states for robust and low power MRAM devices. These $360^\circ$ domain wall (DW) or "twisted onion" states can have clockwise or counterclockwise circulation, the two states for data storage. Reliable switching between the states is necessary for any realistic device. We accomplish this switching by applying a circular Oersted field created by passing current through a metal atomic force microscope tip placed at the center of the ring. After initializing in an onion state, we rotate the DWs to one side of the ring by passing a current through the center, and can switch between the two twisted states by reversing the current, causing the DWs to split and meet again on the opposite side of the ring. A larger current will annihilate the DWs and create a perfect vortex state in the rings.Comment: 5 pages, 5 figure

Microbiota composition of simultaneously colonized mice housed under either a gnotobiotic isolator or individually ventilated cage regime

Germ-free rodents colonized with microbiotas of interest are used for host-microbiota investigations and for testing microbiota-targeted therapeutic candidates. Traditionally, isolators are used for housing such gnotobiotic rodents due to optimal protection from the environment, but research groups focused on the microbiome are increasingly combining or substituting isolator housing with individually ventilated cage (IVC) systems. We compared the effect of housing systems on the gut microbiota composition of germ-free mice colonized with a complex microbiota and housed in either multiple IVC cages in an IVC facility or in multiple open-top cages in an isolator during three generations and five months. No increase in bacterial diversity as assessed by 16S rRNA gene sequencing was observed in the IVC cages, despite not applying completely aseptic cage changes. The donor bacterial community was equally represented in both housing systems. Time-dependent clustering between generations was observed in both systems, but was strongest in the IVC cages. Different relative abundance of a Rikenellaceae genus contributed to separate clustering of the isolator and IVC communities. Our data suggest that complex microbiotas are protected in IVC systems, but challenges related to temporal dynamics should be addressed

Fock terms in the quark-meson coupling model

The mean field description of nuclear matter in the quark-meson coupling model is improved by the inclusion of exchange contributions (Fock terms). The inclusion of Fock terms allows us to explore the momentum dependence of meson-nucleon vertices and the role of pionic degrees of freedom in matter. It is found that the Fock terms maintain the previous predictions of the model for the in-medium properties of the nucleon and for the nuclear incompressibility. The Fock terms significantly increase the absolute values of the single-particle, four-component scalar and vector potentials, a feature that is relevant for the spin-orbit splitting in finite nuclei.Comment: RevTex, 17 pages, 4 Postscript figures, version to appear in Nucl. Phys.

Knowledge of learning disabilities: the relationship with choice, duty of care and non-aversive approaches

The present study examines the relationship between the knowledge of the diagnostic criteria for a learning disability (based on DSM IV criteria), care practices and experience in health care and social care staff. Responses to a questionnaire were analysed in terms of participants emphasis on: recognizing duty of care; enabling choice; non-aversive and aversive strategies. Results indicated that the knowledge of the criteria for a learning disability was limited, with only I6% of the sample correctly identifying all three criteria. There were no significant differences between the two groups in relation to experience or level of knowledge. No clear cut differences were found between the groups in relation to tendency to emphasize a particular management approach, with the strategies adopted appearing to be influenced by vignettes used in this study. Participants tended to give responses that identified both a recognition of their duty of care to clients and the need to enable choice. Limitations of this study are discussed

Phylogenetic analyses of diverse <i>Podaxis</i> specimens from Southern Africa reveal hidden diversity and new insights into associations with termites

<p>Although frequently found on mounds of the grass-cutting termite genus . Trinervitermes, virtually nothing is known about the natural history of the fungal genus . Podaxis (Agaricaceae) nor why it associates with termite mounds. More than 40 species of this secotioid genus have been described since Linnaeus characterised the first species in 1771. However, taxonomic confusion arose when most of these species were reduced to synonymy with . Podaxis pistillaris in 1933. Although a few more species have since been described, the vast majority of specimens worldwide are still treated as . P. pistillaris. Using 45 fresh and herbarium specimens from Southern Africa, four from North America and one each from Ethiopia, and Kenya, we constructed the first comprehensive phylogeny of the genus. Four of the genotyped specimens were more than 100 y old. With the exception of the type specimen of . Podaxis rugospora, all herbarium specimens were labelled as . P. pistillaris or . Podaxis sp. However, our data shows that the genus contains at least five well-supported clades with significant inter-clade differences in spore length, width and wall thickness, and fruiting body length, supporting that clades likely represent distinct . Podaxis species. Certain clades consistently associate with termites while others appear entirely free-living.</p

Unstable states in QED of strong magnetic fields

We question the use of stable asymptotic scattering states in QED of strong magnetic fields. To correctly describe excited Landau states and photons above the pair creation threshold the asymptotic fields are chosen as generalized Licht fields. In this way the off-shell behavior of unstable particles is automatically taken into account, and the resonant divergences that occur in scattering cross sections in the presence of a strong external magnetic field are avoided. While in a limiting case the conventional electron propagator with Breit-Wigner form is obtained, in this formalism it is also possible to calculate $S$-matrix elements with external unstable particles.Comment: Revtex, 7 pages. To appear in Phys. Rev. D53(2