Determining how functionally diverse intertidal sediment species preserve mudflat ecosystem properties after abrupt biodiversity loss

As a result of anthropogenic climate change, extreme climatic events have increased in frequency, severity, and longevity. The consequences for community structure after a catastrophic event have been well studied. However, changes in ecosystem functioning that occur after such an event, including ecosystemrecovery, are still uncertain. A catastrophic event was simulated in an intertidalsedimentary habitat. Postevent sediment replicates were assigned to one of four recovery scenarios: (1) no recovery, (2) migration recovery, and recovery by differential opportunistic colonisation by (3) the polychaete worm Hediste diversicolor and (4) the mud snail Peringia ulvae, two locally dominant infauna species. These are compared with a control scenario not subjected to the event. The simulated extreme event caused a shift in habitat state due to a reduction in mobile macrofauna abundance and an increase in microphytobenthos biomass. Migratory recovery of species and the simulated opportunistic expansion of a single species ameliorated this shift and, for some metrics, functional compensation for the loss of other species and the preservation of certain ecosystem functions was observed. The dominant species identity during postevent habitat recovery can have considerable effects on important ecosystem processes and functions with consequences that may result in functional regime shifts in a habitat and alter coastal stability

Varieties of Limited Access Orders: The nexus between politics and economics in hybrid regimes

This article advances our understanding of differences in hybrid stability by going beyond existing regime typologies that separate the study of political institutions from the study of economic institutions. It combines the work of Douglass North, John Wallis, and Barry Weingast (NWW) on varieties of social orders with the literature on political and economic regime typologies and dynamics to understand hybrid regimes as Limited Access Orders (LAOs) that differ in the way dominant elites limit access to political and economic resources. Based on a measurement of political and economic access applied to seven post‐Soviet states, the article identifies four types of LAOs. Challenging NWW's claim, it shows that hybrid regimes can combine different degrees of political and economic access to sustain stability. Our typology allows to form theoretical expectations about the kinds of political and/or economic changes that will move different types of LAOs toward more openness or closure

A generic C1C^1 map has no absolutely continuous invariant probability measure

Let $M$ be a smooth compact manifold (maybe with boundary, maybe disconnected) of any dimension $d \ge 1$. We consider the set of $C^1$ maps $f:M\to M$ which have no absolutely continuous (with respect to Lebesgue) invariant probability measure. We show that this is a residual (dense $G_\delta) set in the$C^1$ topology. In the course of the proof, we need a generalization of the usual Rokhlin tower lemma to non-invariant measures. That result may be of independent interest.Comment: 12 page

Effects Of Sample Orientation On The Corrosion Of Zinc In Ammonium Sulfate And Sodium Hydroxide Solutions

The corrosion and electrochemical properties of three zinc single crystal surfaces with different orientations have been investigated. In near-neutral 1 M (NH4)2SO4, the corrosion rates on all three surfaces were found to be similar. However, the SEM morphologies of the corresponding corroded surfaces were markedly different from each other, but consistent with preferential attack of {1120} surfaces. In alkaline 0.5 N NaOH solution, the three sample orientations showed significantly different reactivities, with the (1120) surface exhibiting the highest reactivity and corrosion rate. Here, passivation ultimately occurred and the difference in the corrosion performance of the three surfaces, even for small overvoltages, is attributed to the presence of oxide or hydrated oxide films. © 1991

High-resolution computed tomography reconstructions of invertebrate burrow systems

The architecture of biogenic structures can be highly influential in determining species contributions to major soil and sediment processes, but detailed 3-D characterisations are rare and descriptors of form and complexity are lacking. Here we provide replicate high-resolution micro-focus computed tomography (μ-CT) data for the complete burrow systems of three co-occurring, but functionally contrasting, sediment-dwelling inter-tidal invertebrates assembled alone, and in combination, in representative model aquaria. These data (≤2,000 raw image slices aquarium−1, isotropic voxel resolution, 81 μm) provide reference models that can be used for the development of novel structural analysis routines that will be of value within the fields of ecology, pedology, geomorphology, palaeobiology, ichnology and mechanical engineering. We also envisage opportunity for those investigating transport networks, vascular systems, plant rooting systems, neuron connectivity patterns, or those developing image analysis or statistics related to pattern or shape recognition. The dataset will allow investigators to develop or test novel methodology and ideas without the need to generate a complete three-dimensional computation of exemplar architecture

Probe-sample interaction in aperture-type THz near-field microscopy of complementary resonators

Subwavelength complementary metallic resonators operating in the terahertz (THz) regime are investigated with aperture near-field microscopy and spectroscopy. In contrast to far-field methods, the spectra of individual isolated resonators can be retrieved. We find that we can experimentally gain spectral information without modifying the spectral properties of the resonator with the aperture-type near-field probe by operating it at a separation distance greater than 10 μ {m}

A Submaximal Field Test of Aerobic Capacity does not Accurately Reflect VO2max in Career Firefighters

International Journal of Exercise Science 15(4): 221-230, 2022. Adequate aerobic capacity is crucial to maintaining firefighter safety. The purpose of this study was to compare predicted VO2max scores from a submaximal and maximal step test. Eighteen career male firefighters from a medium sized urban municipality completed both a submaximal Forestry step test and a maximal laboratory WFI step test. A lack of association (p = .017) and low level of agreement (p = .015) was determined between step test protocols producing a mean bias of ± 5.61 mL.kg-1/min-1 with most scores being overestimated. Use of the Forestry step test to predict true VO2max in firefighters should be used with caution when classifying firefighter fitness

On the stability of periodic orbits in delay equations with large delay

We prove a necessary and sufficient criterion for the exponential stability of periodic solutions of delay differential equations with large delay. We show that for sufficiently large delay the Floquet spectrum near criticality is characterized by a set of curves, which we call asymptotic continuous spectrum, that is independent on the delay.Comment: postprint versio