PYRAZOLYL-BRIDGED IRIDIUM DIMERS .2. CONTRASTING MODES OF 2-CENTER OXIDATIVE ADDITION TO A BIMETALLIC SYSTEM AND REDUCTIVE ACCESS TO THE STARTING COMPLEX - 3 KEY DIIRIDIUM STRUCTURES REPRESENTING SHORT NON-BONDING AND LONG AND SHORT BONDING METAL-METAL INTERACTIONS

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Highly repetitive DNA sequences provide evidence for a lack of gene flow between morphological forms of Herdmania momus (Ascidiacea: Stolidobranchia).

The genomic structure of two morphological forms of the pyurid ascidian Herdmania momus — H. momus forma curvata and H. momus forma grandis—are compared using a rapidly evolving highly repetitive element isolated from the genome of H. momus forma curvata. A 663 bp (base pair) Cla I satellite sequence is present only in the genome of H. momus forma curvata, and hence can be used as a form-specific marker. Low-stringency Southern blot analyses, using the Cla I satellite as a probe, revealed that the genomes of H. momus forma grandis and another pyurid ascidian, Pyura stolonifera, do not contain similar sequences to the H. momus forma curvata repetitive element. In addition to this genomic dissimilarity, there are a number of significant reproductive and developmental differences between the two H. momus forms, and interform fertilisation rates are significantly lower than intraform rates. The molecular, reproductive and developmental differences between H. momus forma curvata and H. momus forma grandis indicate the presence of strong barriers to gene flow

Differential vulnerability to climate change yields novel deep-reef communities

The effects of climate-driven ocean change on reef habitat-forming species are diverse(1,2) and can be deleterious to the structure and functioning of seafloor communities(3-5). Although responses of shallow coral- or seaweed-based reef communities to environmental changes are a focus of ecological research in the coastal zone(1,4-6), the ecology of habitat-forming organisms on deeper mesophotic reefs remains poorly known. These reefs are typically highly biodiverses(7,8) and productive as a result of massive nutrient recycling(9). Based on seafloor imagery obtained from an autonomous underwater vehicle(8), we related change in community composition on deep reefs (30-90 m) across a latitudinal gradient (25-45 degrees S) in southeastern Australia to high-resolution environmental and oceanographic data, and predicted future changes using downscaled climate change projections for the 2060s(10-12). This region is recognized as a global hotspot for ocean warming(13). The models show an overall tropicalization trend in these deep temperate reef communities, but different functional groups associate differentially to environmental drivers and display a diversity of responses to projected ocean change. We predict the emergence of novel deep-reef assemblages by the 2060s that have no counterpart on reefs today, which is likely to underpin shifts in biodiversity and ecosystem functioning

Capturing the cornerstones of coral reef resilience: linking theory to practice.

Coral reefs can undergo unexpected and dramatic changes in community composition, so called phase shifts. This can have profound consequences for ecosystem services upon which human welfare depends. Understanding of this behavior is in many aspects still in its infancy. Resilience has been argued to provide insurance against unforeseen ecosystem responses in the face of environmental change, and has become a prime goal for the management of coral reefs. However, diverse definitions of resilience can be found in the literature, making its meaning ambiguous. Several studies have used the term as a theoretical framework and concern regarding its practical applicability has been raised. Consequently, operationalizing theory to make resilience observable is an important task, particularly for policy makers and managers dealing with pressing environmental problems. Ultimately this requires some type of empirical assessments, something that has proven difficult due to the multidimensional nature of the concept. Biodiversity, spatial heterogeneity, and connectivity have been proposed as cornerstones of resilience as they may provide insurance against ecological uncertainty. The aim of this article is to provide an overview of the divergent uses of the concept and to propose empirical indicators of the cornerstones of coral reef resilience. These indicators include functional group approaches, the ratios of "good" and "bad" colonizers of space, measurements of spatial heterogeneity, and estimates of potential space availability against grazing capacity. The essence of these operational indicators of resilience is to use them as predictive tools to recognize vulnerability before disturbance occurs that may lead to abrupt phase shifts. Moving toward operationalizing resilience theory is imperative to the successful management of coral reefs in an increasingly disturbed and human-dominated environment

Thermo-responsive nanomaterials for thermoelectric generation

In the past decades, as an emission-free technique capable of realizing direct energy conversion between heat and electricity, thermoelectric materials/applications have attracted extensive attention. The efficiency of thermoelectric modules/devices is dominated by the material dimensionless figure of merit, zT. zT of thermoelectric materials can be enhanced through both optimizing carrier transportation properties and refraining the lattice thermal conductivity. Module design can also influence the energy conversion efficiency. Proper module design, such as segmented or cascade design, can effectively utilize the potential of composing materials. Furthermore, through proper device design, the thermoelectric modules can be designed as both flexible and rigid types and applied in both niche and macro-fields