We exhibit a surprising connection between the following two concepts: Brown representability which arises in stable homotopy theory, and flat covers which arise in module theory. It is shown that Brown representability holds for a compactly generated triangulated category if and only if for every additive functor from the category of compact objects into the category of abelian groups a flat c...

In this essay, I examine the curved spacetime formulation of Newtonian gravity known as Newton–Cartan gravity and compare it with flat spacetime formulations. Two versions of Newton–Cartan gravity can be identified in the physics literature—a ‘‘weak’’ version and a ‘‘strong’’ version. The strong version has a constrained Hamiltonian formulation and consequently a well-defined gauge structure, w...

The article focuses on the principles of strong concentration polarisation of flat and curved interfaces including the phenomenon of the limiting current. It is shown both theoretically and experimentally that electroosmosis of the second kind near the curved interface causes an important change of characteristics of concentration polarisation and a rapid growth of the current through an interf...

The notion of a $\mathcal C$-filtered object, where C$ is some (typically small) collection objects in Grothendieck category, has become ubiquitous since the solution Flat Cover Conjecture around year 2000. We introduce

Literature about entropy generation analysis of a wavy enclosure is scare. In this paper. a FORTRAN cod using an explicit finite-volume method was provided for estimating the entropy production due to the natural convection heat transfer in a cosine wavy absorber solar collector. The volumetric entropy generation terms both the heat transfer term and the friction term were straightly calculated...

Temporal dynamics and vertical patterns in bacterial abundances and activities were studied in a shallow subtidal sand flat in the Sylt-Rømø Basin (North Frisian Wadden Sea, Germany.) Extracellular enzymatic activities, bacterial carbon production and community respiration showed strong (factor of 4–5) temporal variations that 5 were mostly related to seasonal temperature change, but also to ch...

What I intended for this part was simply inspection of pairwise scatterplots and correlation coefficients. (Three-dimensional exploration — 3-D plots, or 2-D scatterplots with panels for different ranges of a third variable — might also be useful, but was more than I expected and in any event my limited exploration of these didn’t reveal anything noteworthy.) Because many of the variables have ...

The cover image is based on the Research Article Catecholaminergic axon innervation and morphology in flat-mounts of atria ventricles mice by Ariege Bizanti et al., https://doi.org/10.1002/cne.25444. Image Credit: Zixi Cheng.

Supplying adequate amounts of soil N for plant growth during the growing season and across large agricultural fields is a challenge for conservational agricultural systems with cover crops. Knowledge about cover crop effects on N comes mostly from small, flat research plots and performance of cover crops across topographically diverse agricultural land is poorly understood. Our objective was to...