Anisotropy and non-universality in scaling laws of the large scale energy spectrum in rotating turbulence

Rapidly rotating turbulent flow is characterized by the emergence of columnar structures that are representative of quasi-two dimensional behavior of the flow. It is known that when energy is injected into the fluid at an intermediate scale $L_f$, it cascades towards smaller as well as larger scales. In this paper we analyze the flow in the \textit{inverse cascade} range at a small but fixed Rossby number, {$\mathcal{R}o_f \approx 0.05$}. Several {numerical simulations with} helical and non-helical forcing functions are considered in periodic boxes with unit aspect ratio. In order to resolve the inverse cascade range with {reasonably} large Reynolds number, the analysis is based on large eddy simulations which include the effect of helicity on eddy viscosity and eddy noise. Thus, we model the small scales and resolve explicitly the large scales. We show that the large-scale energy spectrum has at least two solutions: one that is consistent with Kolmogorov-Kraichnan-Batchelor-Leith phenomenology for the inverse cascade of energy in two-dimensional (2D) turbulence with a {$\sim k_{\perp}^{-5/3}$} scaling, and the other that corresponds to a steeper {$\sim k_{\perp}^{-3}$} spectrum in which the three-dimensional (3D) modes release a substantial fraction of their energy per unit time to 2D modes. {The spectrum that} emerges {depends on} the anisotropy of the forcing function{,} the former solution prevailing for forcings in which more energy is injected into 2D modes while the latter prevails for isotropic forcing. {In the case of anisotropic forcing, whence the energy} goes from the 2D to the 3D modes at low wavenumbers, large-scale shear is created resulting in another time scale $\tau_{sh}$, associated with shear, {thereby producing} a $\sim k^{-1}$ spectrum for the {total energy} with the 2D modes still following a {$\sim k_{\perp}^{-5/3}$} scaling

Rethinking sustainability: Questioning old perspectives and developing new ones

The concept of sustainability is still progressing, being complex and contested, and is therefore under continuous discussion and research. This special volume comprises 29 articles exploring recent developments of sustainability concepts, approaches, strategies, policies, and practices, as well as their roles and applicability in different geographic, socio-cultural and economic contexts. The majority of the articles were presented at the 22nd conference of the International Sustainable Development Research Society (ISDRS), held in Lisbon, Portugal, in July 2016. The articles address six overarching themes: i) global perspectives on sustainability challenges, policies and models; ii) the next frontiers of sustainability for corporations, iii) integration of non-traditional aspects and new forms of knowledge in sustainability research, iv) planning for sustainable development and sustainable cities, v) (higher) education for sustainable development and vi) human resources and sustainability. A summary of each article is given in this editorial, showing the diversity of themes, from theoretical and practical perspectives, and the broad range of different methods and research formats. The research presented in the articles was carried out in more than 17 countries on five continents. Notwithstanding the many efforts around rethinking sustainability research and practices, there are still many challenges to face and further opportunities for research on the topic

Acute mountain sickness.

Acute mountain sickness (AMS) is a clinical syndrome occurring in otherwise healthy normal individuals who ascend rapidly to high altitude. Symptoms develop over a period ofa few hours or days. The usual symptoms include headache, anorexia, nausea, vomiting, lethargy, unsteadiness of gait, undue dyspnoea on moderate exertion and interrupted sleep. AMS is unrelated to physical fitness, sex or age except that young children over two years of age are unduly susceptible. One of the striking features ofAMS is the wide variation in individual susceptibility which is to some extent consistent. Some subjects never experience symptoms at any altitude while others have repeated attacks on ascending to quite modest altitudes. Rapid ascent to altitudes of 2500 to 3000m will produce symptoms in some subjects while after ascent over 23 days to 5000m most subjects will be affected, some to a marked degree. In general, the more rapid the ascent, the higher the altitude reached and the greater the physical exertion involved, the more severe AMS will be. Ifthe subjects stay at the altitude reached there is a tendency for acclimatization to occur and symptoms to remit over 1-7 days

A case-based reasoning approach to learning state-based behavior

Learning from Observation involves creating agents that observe experts performing tasks and imitate them. Case-Based Reasoning (CBR) is a tool that can be used for this purpose. Regular CBR can only learn memoryless behavior: behavior that doesn't rely on the past. Temporal Backtracking (TB) is an approach to learning state-based behavior that uses re-cency as its inductive bias, which may or may not be relevant to the agent behavior. We show how TB can be viewed as a particular case of a more generalized case-based approach to learning state-based behavior that can accommodate other inductive biases. We then propose five alternative similarity metrics to learn three different state-based behaviors in a 2D vacuum cleaner domain, and compare their performance to the TB algorithm's performance. We show that none of the proposed metrics (nor TB) is a one-size-fits all algorithm for learning state-based behavior

Aprt/Opn double knockout mice: Osteopontin is a modifier of kidney stone disease severity

Aprt/Opn double knockout mice: Osteopontin is a modifier of kidney stone disease severity.BackgroundOsteopontin (OPN) is reported to have two distinct functions in kidney disease: Promotion of inflammation at sites of tissue injury, and inhibition of calcium oxalate monohydrate stone formation. However, many of the studies supporting these functions were carried out in animal models of acute renal injury or in cultured cells; thus, the role of OPN in chronic renal disease is not well defined. We examined the role of OPN in adenine phosphoribosyltransferase (Aprt) knockout mice, in which inflammation and formation of 2,8-dihydroxyadenine (DHA) kidney stones are prominent features, by generating Aprt/Opn double knockout mice.MethodsWe characterized the phenotypes of six- and 12-week-old Aprt-/- Opn-/-, Aprt-/- Opn+/+, Aprt+/+ Opn-/-, and Aprt+/+ Opn+/+ male and female mice using biochemical, histologic, immunohistochemical, and in situ hybridization techniques.ResultsAt 6 weeks of age, there was no difference in phenotype between double knockout and Aprt knockout mice. At 12 weeks, there was increased adenine and DHA excretion, renal crystal deposition, and inflammation in double knockout versus Aprt knockout male mice. Double knockout and Aprt knockout female mice at 12 weeks had less pathology than their male counterparts, but kidneys from double knockout females showed more inflammation compared with Aprt knockout females; both genotypes had similar levels of DHA crystal deposition.ConclusionWe conclude that (1) OPN is a major inhibitor of DHA crystal deposition and inflammation in male mice; and (2) OPN is a major modifier of the inflammatory response but not of crystal deposition in female mice. Thus, separate mechanisms appear responsible for the tissue changes seen in DKO males versus females