Time-resolved X-ray microscopy of nanoparticle aggregates under oscillatory shear

Of all current detection techniques with nanometer resolution, only X-ray microscopy allows imaging nanoparticles in suspension. Can it also be used to investigate structural dynamics? When studying response to mechanical stimuli, the challenge lies in applying them with precision comparable to spatial resolution. In the first shear experiments performed in an X-ray microscope, we accomplished this by inserting a piezo actuator driven shear cell into the focal plane of a scanning transmission X-ray microscope (STXM). Thus shear-induced reorganization of magnetite nanoparticle aggregates could be demonstrated in suspension. As X-ray microscopy proves suitable for studying structural change, new prospects open up in physics at small length scales.Comment: submitted to J. Synchrot. Radia

Values: Helping Agricultural Producers Find Motivation by Focusing on What Matters

This fact sheet addresses the importance of tuning into values as a way of maintaining motivation and promoting mental health for agricultural producers

Responding to Financial Stress for Agricultural Producers and Couples

Finances are a necessary component of running an agricultural production and with an uncertain economy, drought conditions, and rising costs, financial stress is increasingly common. Although financial stress is linked with poor individual and relationship outcomes, research suggests that there are effective ways to manage financial stress so that it does not reduce personal or relationship well-being. We review the body\u27s response to stressors and how to respond rather than react to stress. We present specific strategies couples can use to navigate financial stress together. We include ideas for practical application for individuals seeking to improve the way they manage financial stress

Accepting Uncomfortable Emotions: Learning From Car Dashboards and Manure

Agricultural producers can face many stressors, such as long hours coupled with challenging, unpredictable conditions, which can give rise to challenging thoughts and feelings at times. Phrases you may hear in modern culture as you approach difficulty may be pull yourself together, quit worrying, or get over it. However, these aren\u27t the best processes for working through hard emotions. Cultivating acceptance is a way to combat traditional rationalization and work through emotions

Coping With Grief and Loss for Agricultural Producers

As humans, we are social beings who form strong relationships; when these relationships end, through death, divorce, or estrangement, it is natural to feel a sense of loss. This resource is meant to provide some ideas for agricultural producers (individuals and families) seeking to cope with and respond to losing a loved one. We also include information for agricultural producers experiencing other types of loss, such as losing the farm or livestock

Paleocene Radiolaria from DSDP Leg 36-Site 329, Maurice Ewing Bank, Malvinas Plateau: biostratigraphic response

The carbonatic succession of the Maurice Ewing Bank in the Malvinas Plateau, presents records of remarkable paleoceanographic changes in the South Atlantic Ocean, and documents the interval between its opening and the stabilization of the circumpolar current. A report of the Paleocene radiolarian fauna recovered in the Cores 33 and 32 (Section 4) of the DSDP Leg 36-Site 329 is presented herein. The samples, composed mainly by micritic limestones, were chemically treated with a solution of hydrogen peroxide (H2O2) and sodium hexametaphosphate (Na16P14O43). Afterward, they were soaked in a solution of chloridric acid (HCl). The studied microfauna shows low diversity and abundance and is composed by the genera Amphisphaera, Haliomma, Amphymenium, Spongodiscus, Lithelius, Dictyomitra, Dendrospyris, Bathropyramis and Siphocampe. The original biostratigraphic framework proposed for the DSDP Leg 36-Site 329 (based on nannofossils and foraminifers) assigns a Paleocene age to the rocks of the Cores 33 and 32 (Section 4). Radiolarian absence in the Paleocene-Oligocene interval is due to the poor preservation of the specimens. However, the co-occurrence of Amphisphaera priva (Foreman) Hollis and Dictyomitra andersoni (Campbell and Clark) Foreman allows us to sustain at least a Late Paleocene age for the Core 33. The assemblages recovered in the Cores 33 and 32 (Section 4) exhibit some similarity with Paleocene faunas reported in the New Zealand region. Forthcoming studies based on this radiolarian microfauna can provide relevant paleoceanographic data about the South Atlantic Ocean during the Late Paleocene.Simposio VI: Microfósiles del Mesozoico y Cenozoico de América del Sur y Antártida. Nuevas aplicaciones y problemáticas asociadasFacultad de Ciencias Naturales y Muse

Magnetic Structures of High Temperature Phases of TbBaCo2O5.5

Neutron diffraction studies have been carried out on a single crystal of oxygen-deficient perovskite TbBaCo2O5.5 in the temperature range of 7-370 K. There have been observed several magnetic or structural transitions. Among these, the existence of the transitions to the insulating phase from the metallic one at ~340 K, to the one with the ferromagnetic moment at ~280 K and possibly to the antiferromagnetic one at ~260 K, with decreasing temperature T correspond to those reported in former works. We have studied the magnetic structures at 270 K and 250 K and found that all Co3+ ions of the CoO6 octahedra are in the low spin state and those of the CoO5 pyramids carry spins which are possibly in the intermediate spin state. Non-collinear magnetic structures are proposed at these temperatures. Two other transitions have also been observed at the temperatures, ~100 K and ~250 K.Comment: 9 pages, 2 tables, 10 figure

Neutron diffraction, magnetization and ESR studies of pseudocubic Nd(0.75)Ba(0.25)MnO3 and its unusual critical behavior above Tc

Results of structural neutron diffraction study, magnetization and ESR measure-ments are presented for insulating Nd0.75Ba0.25MnO3, Tc = 129 K. The crystal structure is refined in the range 4.2-300 K. The compound is found to exhibit the Jahn-Teller (JT) transition at 250 K. The field cooled (FC) magnetization data are in a reasonable agreement with the predictions for a 3D isotropic ferromagnet above Tc. However, these measurements reveal a difference between the FC and zero FC data in the paramagnetic region. ESR results are also in a correspondence with behavior of a cubic ferromagnet above T* = 143 K. It is shown that an anisotropic exchange coupling of the Mn and Nd magnetic moments can give a substantial contribution in ESR linewidth masking its critical enhan-cement. The different temperature treatments of the sample reveal a temperature hysteresis of the ESR spectra below T* indicating an anomalous response in the paramagnetic region. The study of phase transition in this manganite suggests change in its character from the second to first order at T*. The conventional free energy including the magnetization and magnetic field is not found to describe the first order transition. This suggests that the charge, orbital and JT phonon degrees of freedom, in addition to magnetization, may be the critical variables, the unusual character of the transition being determined by their coupling. Unconventional critical behavior is attributed to orbital liquid metallic phase that coexists with the initial orbital ordered phase below T*.Comment: 18 pages, 5 figures, submitted to Phys. Rev.