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Simulations of the dust cycle and its interactions with the changing Earth system are hindered by the empirical nature of dust emission parameterizations in weather and climate models. Here we take a step towards improving dust cycle simulations by using a combination of theory and numerical simulations to derive a physically based dust emission parameterization. Our parameterization is straightforward to implement into large-scale models, as it depends only on the wind friction velocity and the soil's threshold friction velocity. Moreover, it accounts for two processes missing from most existing parameterizations: a soil's increased ability to produce dust under saltation bombardment as it becomes more erodible, and the increased scaling of the dust flux with wind speed as a soil becomes less erodible. Our treatment of both these processes is supported by a compilation of quality-controlled vertical dust flux measurements. Furthermore, our scheme reproduces this measurement compilation with substantially less error than the existing dust flux parameterizations we were able to compare against. A critical insight from both our theory and the measurement compilation is that dust fluxes are substantially more sensitive to the soil's threshold friction velocity than most current schemes account for.

The crystal structure, cryogenic magnetic properties, and magnetocaloric performance of double perovskite Eu 2 NiMnO 6 (ENMO), Gd 2 NiMnO 6 (GNMO), and Tb 2 NiMnO 6 (TNMO) ceramic powder samples synthesized by solid-state method have been investigated. X-ray diffraction structural investigation reveal that all compounds crystallize in the monoclinic structure with a P2 1 /n space group. A ferromagnetic to paramagnetic (FM-PM) second-order phase transition occurred in ENMO, GNMO, and TNMO at 143, 130, and 112 K, respectively. Maximum magnetic entropy changes and relative cooling power with a 5 T applied magnetic field are determined to be 3.2, 3.8, 3.5 J/kgK and 150, 182, 176 J/kg for the investigated samples, respectively. The change in structural, magnetic, and magnetocaloric effect attributed to the superexchange mechanism of Ni 2+ –O–Mn 3+ and Ni 2+ –O–Mn 4+ . The various atomic sizes of Eu, Gd, and Tb affect the ratio of Mn 4+ /Mn 3+ , which is responsible for the considerable change in properties of double perovskite.

Phenology refers to the seasonal timing patterns commonly exhibited by life on Earth, from blooming flowers to breeding birds to human agriculture. Climate change is altering abiotic seasonality (e.g., longer summers) and in turn, phenological patterns contained within. However, how phenology should evolve is still an unsolved problem. This problem lies at the crux of predicting future phenological changes that will likely have substantial ecosystem consequences, and more fundamentally, of understanding an undeniably global phenomenon. Most studies have associated proximate environmental variables with phenological responses in case-specific ways, making it difficult to contextualize observations within a general evolutionary framework. We outline the complex but universal ways in which seasonal timing maps onto evolutionary fitness. We borrow lessons from life history theory and evolutionary demography that have benefited from a first principles-based theoretical scaffold. Lastly, we identify key questions for theorists and empiricists to help advance our general understanding of phenology.

\"With a population of about six hundred million people, and a combined GNP of more than US$ 2.4 trillion, the ASEAN Economic Community (AEC) is set to become the seventh largest economy in the world. Launched in December 2015, the AEC unveiled initiatives to create a single market and production zone, a competitive and equitable region, and integrated links to the global economy. ASEAN Champions seeks to address the role of the strong local firms in regional integration, how these 'champions' succeeded and endured, despite facing adverse circumstances, and the factors that facilitated or impeded their participation in regional integration. The book provides insights for future firm and government-led strategies to enhance the integration process. By complementing current narratives that focus on macroeconomic, socio-political, and trade considerations, Park, Ungson and Francisco offer an enlightening and engaging read, ideally suited to academics and professionals alike\"-- Provided by publisher.

In situ femtosecond X-ray diffraction measurements reveal that the dominant mechanism of shock-wave-driven deformation in tantalum changes from twinning to dislocation slip as pressure increases. Deformation caught in the act The effect of shock waves travelling through materials has relevance for various areas of study in geology and materials science. Experiments that probe how materials deform on exposure to shock waves are usually carried out in retrospect of the shock event. This paper reports in situ X-ray diffraction studies of the plastic deformation of textured polycrystalline tantalum on exposure to shock compression with shock pressures ranging from 10 gigapascals to around 300 gigapascals (at which the metal melts). Twinning and slip deformations produce distinct changes to the texture of the tantalum sample and these changes could be observed in the diffraction data. In this way, the researchers observed that the dominant deformation mechanism transitioned from minimal twinning to twinning-dominated to slip-dominated as the shock pressure increased above 150 gigapascals. This dynamic material behaviour would be challenging to observe in experiments carried out after the shock event. Pressure-driven shock waves in solid materials can cause extreme damage and deformation. Understanding this deformation and the associated defects that are created in the material is crucial in the study of a wide range of phenomena, including planetary formation and asteroid impact sites 1 , 2 , 3 , the formation of interstellar dust clouds 4 , ballistic penetrators 5 , spacecraft shielding 6 and ductility in high-performance ceramics 7 . At the lattice level, the basic mechanisms of plastic deformation are twinning (whereby crystallites with a mirror-image lattice form) and slip (whereby lattice dislocations are generated and move), but determining which of these mechanisms is active during deformation is challenging. Experiments that characterized lattice defects 8 , 9 , 10 , 11 have typically examined the microstructure of samples after deformation, and so are complicated by post-shock annealing 12 and reverberations. In addition, measurements have been limited to relatively modest pressures (less than 100 gigapascals). In situ X-ray diffraction experiments can provide insights into the dynamic behaviour of materials 13 , but have only recently been applied to plasticity during shock compression 14 , 15 , 16 , 17 and have yet to provide detailed insight into competing deformation mechanisms. Here we present X-ray diffraction experiments with femtosecond resolution that capture in situ , lattice-level information on the microstructural processes that drive shock-wave-driven deformation. To demonstrate this method we shock-compress the body-centred-cubic material tantalum—an important material for high-energy-density physics owing to its high shock impedance and high X-ray opacity. Tantalum is also a material for which previous shock compression simulations 18 , 19 , 20 and experiments 8 , 9 , 10 , 11 , 12 have provided conflicting information about the dominant deformation mechanism. Our experiments reveal twinning and related lattice rotation occurring on the timescale of tens of picoseconds. In addition, despite the common association between twinning and strong shocks 21 , we find a transition from twinning to dislocation-slip-dominated plasticity at high pressure (more than 150 gigapascals), a regime that recovery experiments cannot accurately access. The techniques demonstrated here will be useful for studying shock waves and other high-strain-rate phenomena, as well as a broad range of processes induced by plasticity.

Neurodegenerative changes in the diabetic retina occurring before diabetic retinopathy could be inevitable by the altered energy (glucose) metabolism, in the sense that dynamic image-processing activity of the retinal neurons is exclusively dependent on glucose. We therefore investigated the morphological changes in the neural retina, including neuronal cell death, of a streptozotocin-induced model of diabetes. Streptozotocin was intravenously injected. Rats were maintained hyperglycaemic without insulin treatment for 1 week and 4, 8, 12, and 24 weeks, respectively. Diabetic retinas were processed for histology, electron microscopy, and immunohistochemistry using the TUNEL method. A slight reduction in the thickness of the inner retina was observed throughout the diabetic retinas and a remarkable reduction was seen in the outer nuclear layer 24 weeks after the onset of diabetes. The post-synaptic processes of horizontal cells in the deep invaginations of the photoreceptors showed degeneration changes from 1 week onwards. A few necrotic ganglion cells were observed after 4 weeks. At 12 weeks, some amacrine cells and a few horizontal cells showed necrotic features. Three to seven cellular layers in the outer nuclear layer and nerve terminals, rolled by the fine processes of the Müller cells near the somata of the degenerated ganglion cells, were apparent at 24 weeks. Apoptosis appeared in a few photoreceptor cells at 4 weeks, and the number of apoptotic photoreceptors increased thereafter. These findings suggest that the visual loss associated with diabetic retinopathy could be attributed to an early phase of substantial photoreceptor loss, in addition to later microangiopathy.