I have performed a two-state mixing analysis between so-called rotational intruder 0+, 2+ and yrast 0+, 2+ states in 112Cd, fitting E2 transition matrix elements to obtain mixing amplitudes and ...matrix elements connecting basis states. Mixing is found to be small for both 0+ and 2+ states. Of two possible solutions, one provides a 0+ mixing amplitude of 0.251– identical to the one derived years ago from 2n transfer data.
1.Ecologists debate the importance of neutral versus niche-based explanations for patterns of species coexistence and whether small-scale data can inform ecological understanding of communities, ...referred to by McNaughton Ecological Monographs, 1983, 53, 291 as 'ecology's cruel dilemma.' Research on phylogenetic relationships, traits and species co-occurrence has attempted to address this topic, with results considerably mixed. 2.We address the hypothesis that plant community assembly is influenced by trait similarity across ecological gradients and this affects mean phylogenetic distance (MPD) of species within sites. We analysed specific leaf area (SLA), maximum plant height and phylogenetic relationships among Serengeti grasses, a system ideally suited to study community assembly because of an ecological gradient in which the dominant plant stress shifts from drought to light competition. 3.Phylogenetic community assembly theory predicts that MPD would be lowest (under-dispersed) at dry sites and greatest (over-dispersed) at sites with higher rainfall. Similarly, theory predicts that low soil nutrient concentrations should filter intolerant species, so that MPD is expected to be under-dispersed at infertile, low-elevation sites and over-dispersed at fertile, higher-elevation sites. However, as gradients of rainfall and soil fertility run counter to one another across the Serengeti, it was unclear how this covariation would influence MPD. 4.Surprisingly, traits showed different evolutionary patterns: SLA displayed convergent evolution while maximum plant height displayed Brownian evolution across the phylogeny. As predicted, statistically under-dispersed assemblages occurred at lower rainfall, infertile sites while statistically over-dispersed assemblages occurred at higher rainfall, fertile sites. However, the pattern across all plots was weak, with most plots showing no statistical pattern of MPD. 5.Multivariate analyses using structural equation modelling, which statistically controlled for covariation among environmental effects, revealed complex direct and indirect effects of environmental variation on MPD, including offsetting direct effects of SLA and maximum plant height due to their different patterns of trait evolution. 6.Synthesis. Spatially counteracting gradients of moisture and soil fertility across the Serengeti, combined with contrasting patterns of trait evolution, obscured the relationship between MPD and any single environmental variable. Our study shows that integrating trait and phylogenetic relationships across ecological gradients yields considerable insight into the ecological mechanisms that determine community composition, but that multivariate techniques may be required to appropriately reveal such patterns.
Understanding the general rules of microbial interactions is central for advancing microbial ecology. Recent studies show that interaction range, interaction strength, and community context determine ...bacterial interactions and the coexistence and evolution of bacteria. We highlight how these factors could contribute to a general understanding of bacterial interactions.
Despite the advances in ecological theory, evidence for the relative importance of the different mechanisms that promote species coexistence is lacking. Some mechanisms depend on the presence of ...interannual fluctuations in the environment combined with interspecific differences in the responses to such fluctuations. Among coexistence mechanisms, niche differentiation and storage effects have received much attention, whereas relative non-linearity (RNL) has been thought to be an unlikely and weak mechanism for multi-species coexistence and remains untested in nature. We quantified the relative contribution of different mechanisms to the coexistence of 19 grassland species by using field-parameterized population models and invasion analysis. Our results showed that 17 out of 19 species had the potential to coexist stably. Species diversity was maintained by RNL and large fluctuation-independent niche differences, i.e., between-species differentiation that is unrelated to interannual variations in environmental factors. Moreover, RNL increased the fitness of species that were less favored by niche differentiation, contributing to their persistence in the community. Storage effect was negligible or destabilizing, making no contribution to stable coexistence. These results, altogether with recent theoretical developments and indirect evidence in published data, call for a reassessment of RNL as a relevant mechanism for multi-species coexistence in nature.
Increasingly, fisheries researchers and managers seek or are compelled to “bridge” Indigenous knowledge systems with Western scientific approaches to understanding and governing fisheries. Here, we ...move beyond the all‐too‐common narrative about integrating or incorporating (too often used as euphemisms for assimilating) other knowledge systems into Western science, instead of building an ethic of knowledge coexistence and complementarity in knowledge generation using Two‐Eyed Seeing as a guiding framework. Two‐Eyed Seeing (Etuaptmumk in Mi’kmaw) embraces “learning to see from one eye with the strengths of Indigenous knowledges and ways of knowing, and from the other eye with the strengths of mainstream knowledges and ways of knowing, and to use both these eyes together, for the benefit of all,” as envisaged by Elder Dr. Albert Marshall. In this paper, we examine the notion of knowledge dichotomies and imperatives for knowledge coexistence and draw parallels between Two‐Eyed Seeing and other analogous Indigenous frameworks from around the world. It is set apart from other Indigenous frameworks in its explicit action imperative—central to Two‐Eyed Seeing is the notion that knowledge transforms the holder and that the holder bears a responsibility to act on that knowledge. We explore its operationalization through three Canadian aquatic and fisheries case‐studies that co‐develop questions, document and mobilize knowledge, and co‐produce insights and decisions. We argue that Two‐Eyed Seeing provides a pathway to a plural coexistence, where time‐tested Indigenous knowledge systems can be paired with, not subsumed by, Western scientific insights for an equitable and sustainable future.
Human activity and land use change impact every landscape on Earth, driving declines in many animal species while benefiting others. Species ecological and life history traits may predict success in ...human‐dominated landscapes such that only species with “winning” combinations of traits will persist in disturbed environments. However, this link between species traits and successful coexistence with humans remains obscured by the complexity of anthropogenic disturbances and variability among study systems. We compiled detection data for 24 mammal species from 61 populations across North America to quantify the effects of (1) the direct presence of people and (2) the human footprint (landscape modification) on mammal occurrence and activity levels. Thirty‐three percent of mammal species exhibited a net negative response (i.e., reduced occurrence or activity) to increasing human presence and/or footprint across populations, whereas 58% of species were positively associated with increasing disturbance. However, apparent benefits of human presence and footprint tended to decrease or disappear at higher disturbance levels, indicative of thresholds in mammal species’ capacity to tolerate disturbance or exploit human‐dominated landscapes. Species ecological and life history traits were strong predictors of their responses to human footprint, with increasing footprint favoring smaller, less carnivorous, faster‐reproducing species. The positive and negative effects of human presence were distributed more randomly with respect to species trait values, with apparent winners and losers across a range of body sizes and dietary guilds. Differential responses by some species to human presence and human footprint highlight the importance of considering these two forms of human disturbance separately when estimating anthropogenic impacts on wildlife. Our approach provides insights into the complex mechanisms through which human activities shape mammal communities globally, revealing the drivers of the loss of larger predators in human‐modified landscapes.
Human activity and land use change are driving declines in many animal species while benefiting others, but predicting which species will successfully coexist with humans remains a challenge. We compiled detection data for 24 mammal species from 61 populations across North America and showed that species life history traits were strong predictors of their responses to human footprint (landscape modification), with increasing footprint favoring smaller, less carnivorous, faster‐reproducing species. Positive and negative effects of direct human presence (e.g., recreation, hunting) were distributed more randomly across species, with apparent winners and losers across a range of body sizes and dietary guilds.
Abstract
The compound Sr
0.5
Ce
0.5
FBiS
2
belongs to the intensively studied family of layered BiS
2
superconductors. It attracts special attention because superconductivity at
T
sc
= 2.8 K was ...found to coexist with local-moment ferromagnetic order with a Curie temperature
T
C
= 7.5 K. Recently it was reported that upon replacing S by Se
T
C
drops and ferromagnetism becomes of an itinerant nature. At the same time
T
sc
increases and it was argued superconductivity coexists with itinerant ferromagnetism. Here we report a muon spin rotation and relaxation study (μSR) conducted to investigate the coexistence of superconductivity and ferromagnetic order in Sr
0.5
Ce
0.5
FBiS
2−
x
Se
x
with
x
= 0.5 and 1.0. By inspecting the muon asymmetry function we find that both phases do not coexist on the microscopic scale, but occupy different sample volumes. For
x
= 0.5 and
x
= 1.0 we find a ferromagnetic volume fraction of ~8 % and ~30 % at
T
= 0.25 K, well below
T
C
= 3.4 K and
T
C
= 3.3 K, respectively. For x = 1.0 (
T
sc
= 2.9 K) the superconducting phase occupies most (~64 %) of the remaining sample volume, as shown by transverse field experiments that probe the Gaussian damping due to the vortex lattice. We conclude ferromagnetism and superconductivity are macroscopically phase separated.
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