Short Branches Research Articles

Improving Environmental Stress Cracking Resistance of High-Density Polyethylene Grades by Comonomer Addition and Nanocomposite Approach.

The aim of this paper is to determine the effect of polymer density, correlated to the comonomer content, and nanosilica addition on the mechanical and Environmental Stress Cracking Resistance (ESCR) characteristics of high-density polyethylene (HDPE). In this regard, five HDPE samples with similar Melt Flow Index (MFI) and molar mass but various densities were acquired from a petrochemical plant. Two polymerization reactors work in series and differ only in the amount of 1-buene comonomer fed to the second reactor. To ascertain the microstructure of the studied samples, GPC and SSA (successive self-nucleation and annealing) analyses were accomplished. All samples resulted having similar characteristics but slightly various SCB/1000 C=7.26-9.74 (SCB=Short Chain Branching). Consequently, meanwhile studied HDPEs reveal similar notched impact and stress at yield values, the tensile modulus, stress-at-break, and elongation-at-break tend to demonstrate different results with the SCB content. More significantly, ESCR characteristic varied considerably with SCB/1000 C extent, so that higher amount of SCB acknowledged advanced ESCR. Notably, blending HDPE sample containing higher amount of SCB/1000 C, with 3 wt.% of chemically modified nanosilica enhanced ESCR characteristic by 40 %. DFT (Density Functional Theory) calculations unveiled the role of the comonomer, quantitatively by binding energies and qualitatively by Non Covalent Interaction (NCI) plots.

Microstructural design characteristics of high-density polyethylene for thick-walled pressure pipe applications

Advancements in process technology and structure-property relationship-based design of high-density polyethylene has led to development of high-performance bimodal polyethylene grades suitable for large diameter thick-walled pressure pipe applications. These high-density bimodal products have enhanced design life, high pressure rating and sag resistance for fabrication of large diameter thick-walled pipe. Achieving optimal balance of these performance properties require controlled microstructural characteristics. The design characteristics are intricately influenced by catalyst type and process technology employed in resin manufacturing. In this study, we systematically establish correlations between microstructural characteristics of seven commercially available bimodal PE resins, produced using dual slurry or gas phase reactors, and their most relevant performance properties. We conducted comprehensive microstructural characterization of all samples using GPC-IR (high-temperature gel permeation chromatography coupled with an infrared composition detector), 13C NMR (nuclear magnetic resonance), TREF (temperature rising elution fractionation) and DSC (differential scanning calorimetry) techniques. Additionally, we measured mechanical, thermal, and rheological properties, focusing on crystallization kinetics, density, slow crack growth resistance (PENT and strain hardening modulus SHM) and low-frequency shear rheology of these products. Comparisons were made between key properties of interest, including slow crack growth resistance and low-frequency rheology (relevant for sag resistance), and microstructural characteristics. Theoretical and empirical correlations based on phenomenological models were employed for this analysis. The detailed study contributes to determining the critical levels of short and long chain branching, as well as molecular weight distribution characteristics essential to produce bimodal PE-4710 certifiable high-density polyethylene resins with low sag resistance. These design principles may serve as a foundation for the efficient design of reactor recipes and post-reactor modification processes, contributing to the evolution of pressure pipe polyethylene resin development and paving the way for design of next-generation pressure pipe grades.

The influence of low-temperature shear on crystallization of shish-kebab of unimodal/ bimodal C4 short-chain branching polyethylene

The shish crystal, a crucial structure in the formation of shish-kebab crystals, has drawn widespread attention due to its highly oriented chain arrangement, significantly enhancing the mechanical properties of products. This study utilizes polyethylene samples with longer C4 short branches, employing in-situ synchrotron SAXS/WAXD to investigate the influence of short branch length and content on the formation of shish-kebab crystals in unimodal and bimodal polyethylene under low-temperature shear conditions (with supercooling degrees of 13.5 °C and 10.5 °C). The results reveal that the presence of C4 short-chain branching affects system crystallization, but low-temperature shear induces stronger mechanical action on the melt, resulting in better-oriented lamellar crystals compared to high-temperature shear (superheat degrees of 22.5 °C and 19.5 °C), achieving higher orientation. This achieves the control of shish-kebab crystal generation through the stretched network mechanism. Both types of samples with different C4 short-chain branching contents generate shish-kebab crystals during the shear stage, with relatively higher short-chain branching content inducing more shish crystal formation but with less regular structure. The bimodal polyethylene exhibit higher proportions and absolute amounts of final shish crystals compared to the unimodal polyethylene, indicating that high molecular weight portions are conducive to shish crystal generation under shear. The result demonstrates the feasibility of generating shish-kebab crystals during the low-temperature shear process of PE in the presence of C4 branches using the stretched network mechanism under shear flow conditions. Moreover, controlling the degree of entanglement of molecular chains by adjusting shear temperature, branch content, and branch length can modulate two formation mechanisms of shish crystals—coil-stretch transition mechanism at high temperature and stretched network mechanism at low-temperature.

Structural, topological, and rheological characteristics of entangled short-chain branched polymer melts under shear flow in comparison with the linear analog

We present a detailed analysis of the general influence of short branches on the structural, topological, and rheological behaviors of entangled short-chain branched (SCB) polyethylene (PE) melt systems under shear flow via direct comparison with the corresponding linear analogs using extensive atomistic nonequilibrium molecular dynamics (NEMD) simulations, for a wide range of flow strengths. In comparison with the linear melt, the SCB systems generally exhibit more compact chain structures and larger dynamic resistance, in response to an imposed flow field at all flow strengths. These features essentially arise from (i) the increased chain stiffness due to the torsional restriction of backbone atoms around the branch points and (ii) the fast random Brownian motion of short branches via their very short characteristic relaxation time. We analyzed various structural and rheological properties, such as anisotropic chain dimension and orientation and their detailed distributions, topological characteristics of the entanglement network, material functions, chain rotation dynamics, and flow birefringence. Distinctive physical characteristics of the entangled SCB systems exposed by these individual properties can be consistently understood based on the fundamental structural and dynamical roles of short branches. These findings are considered informative in our systematic understanding and prediction for the general rheological behaviors of long entangled SCB polymer systems under flow, and in tuning the material properties of SCB polymers in practical applications.

Replacement of Loops at the Entrance of the Active Pocket of Streptococcus thermophilus 4,6-α-Glucanotransferase Changes Its Catalytic Activity and Product Specificity.

To explore the roles of loops around active pocket in the reuteran type 4,6-α-glucanotransferase (StGtfB) from S. thermophilus, they were individually or simultaneously replaced with those of an isomalto/maltopolysaccharides type 4,6-α-glucanotransferase from L. reuteri. StGtfB with the replaced loops A1, A2 (A1A2) and A1, A2, B (A1A2B), respectively, showed 1.41- and 0.83-fold activities of StGtfB. Two mutants reduced crystallinity and increased starch disorder at 2, 4, and 8 U/g more than StGtfB and increased DP ≤ 5 short branches of starch by 38.01% at 2 U/g, much more than StGtfB by 4.24%. A1A2B modified starches had the lowest retrogradation over 14 days. A1A2 modified starches had the highest percentage of slowly digestible fractions, ranging from 40.32% to 43.34%. StGtfB and its mutants bind substrates by hydrogen bonding and van der Waals forces at their nonidentical amino acid residues, suggesting that loop replacement leads to a different conformation and changes activity and product structure.

Relationship between Chalkiness and the Structural and Physicochemical Properties of Rice Starch at Different Nighttime Temperatures during the Early Grain-Filling Stage.

The chalkiness, starch fine structure, and physiochemical properties of rice starch were analyzed and their correlations were investigated under different nighttime temperatures during the early grain-filling stage. Compared to MT, medium temperature (MT) and low (LNT) and high (HNT) nighttime temperatures resulted in an increased chalky grain rate (CGR) and chalkiness degree (CD). LNT mainly affected the chalkiness by increasing peak1 (short branch chains of amylopectin), the branching degree, and the proportion of small starch granules but decreasing peak2 (long branch chains of amylopectin) and peak3 (amylose branches). This altered the pasting properties, such as by increasing the peak viscosity and final viscosity. However, HNT mainly affected the chalkiness by increasing peak2 and the crystallinity degree but decreasing peak1 and peak3. Regarding the thermal properties, HNT also elevated peak and conclusion temperatures. The CGR and CD were significantly and positively correlated with the proportions of small and medium starch granules, peak1, branching degree, gelatinization enthalpy, setback viscosity, and pasting time but markedly and negatively correlated with the proportion of large starch granules, amylose content, peak3, peak viscosity, and breakdown viscosity. These findings suggest that LNT and HNT disrupted the starch structure, resulting in increased chalkiness. However, their mechanisms of action differ.

Multicentre Experience with Novel Bidirectional Double Cuffed Inner Branches for Complex Endovascular Aortic Repair

This study aimed to report the initial experience with a novel bidirectional double cuff inner branch design for incorporation of renal and mesenteric arteries in patients undergoing fenestrated and branched endovascular aortic repair (F/BEVAR). A retrospective review was undertaken of the experience of F/BEVAR with grafts integrating at least one bidirectional double cuffed inner branch implanted at three tertiary aortic centres between March 2022 and June 2023. All consecutive patients were included. Baseline characteristics, operative data, and follow up data were collected. Results were presented as number or median (interquartile range) unless otherwise stated. Thirteen patients (10 male; median age 72 [68, 77] years) had F/BEVAR using a total of 15 bidirectional double cuffed inner branches (30 cuffs). Indications for bidirectional doubled cuffed inner branches included cranial vessel orientation or double renal arteries in four patients each, common coeliomesenteric trunk in three patients, and early renal artery bifurcation, renal artery origin from a false lumen requiring a flexible route for catheterisation, and surplus configuration in one patient each. Twenty three of the 30 cuffs were used, whereas the remaining seven cuffs were intentionally occluded with vascular plugs. Target vessel incorporation was successful in all bidirectional branches. There was one technical failure related to unsuccessful catheterisation of a left renal artery targeted through a unidirectional caudal inner branch. During a median follow up of seven months there were no instances of target vessel instability or re-interventions and two patients died of causes unrelated to the bidirectional branches. The results of the use of bidirectional double cuff inner branches are promising, with high technical success and no short term branch related complications in this preliminary experience. This could potentially expand the applicability of branch endografting of complex endovascular aortic repairs, but long term results are still missing.

Meconopsis biluoensis (Papaveraceae), a new species revealed by population-level investigation.

Meconopsis biluoensis, a new species of Papaveraceae in an alpine meadow from Yunnan, Southwest China, is described and illustrated. Morphologically, it resembles Meconopsis georgei, while it is distinct in acaulescent and hispid with clearly expanded bases on the leaves. A genus-level molecular phylogenetic analysis supported the closest relationship between M. biluoensis and M. georgei. In a finer population-level molecular phylogenetic analysis using ribosomal DNA (rDNA) and the chloroplast genome, individuals from M. biluoensis and M. georgei were clearly separated, and the extremely short branch length indicated that the two species had a very short differentiation time. The species has currently been assessed as "endangered" (EN) due to its small-sized population and narrow distribution following the IUCN categories and criteria.

A new nuclear phylogeny of the tea family (Theaceae) unravels rapid radiations in genus Camellia

Molecular analyses of rapidly radiating groups often reveal incongruence between gene trees. This mainly results from incomplete lineage sorting, introgression, and gene tree estimation error, which complicate the estimation of phylogenetic relationships. In this study, we reconstruct the phylogeny of Theaceae using 348 nuclear loci from 68 individuals and two outgroup taxa. Sequence data were obtained by target enrichment using the recently released Angiosperm 353 universal probe set applied to herbarium specimens. The robustness of the topologies to variation in data quality was established under a range of different filtering schemes, using both coalescent and concatenation approaches. Our results confirmed most of the previously hypothesized relationships among tribes and genera, while clarifying additional interspecific relationships within the rapidly radiating genus Camellia. We recovered a remarkably high degree of gene tree heterogeneity indicative of rapid radiation in the group and observed cytonuclear conflicts, especially within Camellia. This was especially pronounced around short branches, which we primarily associate with gene tree estimation error. Our analysis also indicates that incomplete lineage sorting (ILS) contributed to gene-tree conflicts and accounted for approximately 14 % of the explained variation, whereas inferred introgression levels were low. Our study advances the understanding of the evolution of this important plant family and provides guidance on the application of target capture methods and the evaluation of key processes that influence phylogenetic discordances.

Genetic intratumour heterogeneity and clonal evolution in extramammary Paget's disease.

All tumour cells in a patient have shared and non-shared genetic alterations, and the diversity of mutations is described as intratumoural heterogeneity (ITH). Multiregion sequencing is a genome sequencing analytical technique used for multiple, spatially-separated biopsy tissues that may further our understanding of ITH and tumour evolution. Although genetic mutations in extramammary Paget's disease (EMPD) have recently been detected by next-generation sequencing analysis, there have been no reports of ITH based on multiregion sequencing in EMPD. Thus, we clarified the landscape of ITH and tumour evolution in EMPD. We performed whole-exome sequencing on 35 tissues (30 tumour tissues and five normal skin samples as a paired control), collected from five patients with EMPD. The rate of private mutations was significantly higher than that of ubiquitous and shared mutations. Ubiquitous mutations were not present in driver genes, and most driver genes exhibited private and shared mutations. The most frequent base substitution was C>T in almost all lesions, and most mutational signatures corresponded to signature 1, 2, 3, and 8. The types of proposed aetiology in most lesions were based on age and AID/APOBEC family and BRCA1/BRCA2 mutations. Evolutionary trees were characterized by short trunks and long branches due to the extremely high ratio of private mutations. In contrast, pathogenic factors, such as base substitutions, mutational signatures, and proposed aetiology, were shared. Tumour evolution in EMPD appears to be characterized by a high level of genetic ITH with shared background factors.

Transcription factor FveMYB117a inhibits axillary bud outgrowth by regulating cytokinin homeostasis in woodland strawberry.

Shoot branching affects plant architecture. In strawberry (Fragaria L.), short branches (crowns) develop from dormant axillary buds to form inflorescences and flowers. While this developmental transition contributes greatly to perenniality and yield in strawberry, its regulatory mechanism remains unclear and understudied. In the woodland strawberry (Fragaria vesca), we identified and characterized 2 independent mutants showing more crowns. Both mutant alleles reside in FveMYB117a, a R2R3-MYB transcription factor gene highly expressed in shoot apical meristems, axillary buds, and young leaves. Transcriptome analysis revealed that the expression of several cytokinin pathway genes was altered in the fvemyb117a mutant. Consistently, active cytokinins were significantly increased in the axillary buds of the fvemyb117a mutant. Exogenous application of cytokinin enhanced crown outgrowth in the wild type, whereas the cytokinin inhibitors suppressed crown outgrowth in the fvemyb117a mutant. FveMYB117a binds directly to the promoters of the cytokinin homeostasis genes FveIPT2 encoding an isopentenyltransferase and FveCKX1 encoding a cytokinin oxidase to regulate their expression. Conversely, the type-B Arabidopsis response regulators FveARR1 and FveARR2b can directly inhibit the expression of FveMYB117a, indicative of a negative feedback regulation. In conclusion, we identified FveMYB117a as a key repressor of crown outgrowth by inhibiting cytokinin accumulation and provide a mechanistic basis for bud fate transition in an herbaceous perennial plant.

Starch spectra of Ampelopteris prolifera (Retz.) Copel, a new addition to the existing lexicon and its comparison with a local potato cultivar (Solanum tuberosum L. cv. Kufri Jyoti)

Novel kinds of starch spectra were generated from a lesser-known plant, making this investigation unique. The recent trend of starch characterization shows the establishment of novel bioresources from nonconventional unexplored databases. The present endeavor was made to obtain the starch fingerprint of Ampelopteris prolifera (rhizome) belonging to seedless vascular plants. For comparison, a commercial local cultivar of potato (Kufri Jyoti) was taken. The starch particle of A. prolifera shows much uniqueness depicting its novelty viz., crystallinity index of 60.04 %, powder diffractogram at (2θ scale)17.57° to 39.78°; this diffractogram pattern is reported from this study as newer one i.e. R type(whereas potato starch is CB type); characteristic peak at 2θ = 20.07° suggests starch-lipid complex formation and V type crystallinity (i.e. RS 5 type); FTIR spectra showing the presence of more short chain branching; high gelatinization temperature(84.62 ± 0.10), particle size and zeta value of A. prolifera is 4.00 ± 0.81 μm and − 18.91 ± 3.58 mV respectively. Bragg's peak from the single crystal X-ray diffraction has been generated for the first time of A. prolifera. Extraction of the starch particle was performed in chilled water. Therefore, the present study suggests wide-spectrum commercial utility and cost-effective production.

THE PROBLEM OF FRAUDULENTLY INSURED AND FINANCIAL SUSTAINABILITY: CASE OF THE TÜRKIYE SOCIAL INSURANCE SYSTEM

Social insurance fraud is a multidimensional and complex problem that affects the sustainability of social security systems and social justice. Nowadays, the most common form of social insurance fraud is fraudulently insured. The aim of this research is to explain the problem of fraudulently insured in its legal, economic, and social aspects and to make solutions for the sustainability of the social security system in Türkiye. This study explains the causes of fraudulent insurance through the differences in access to benefits and rights provided by short and long-term insurance branches and unemployment insurance for 4a and 4b insured persons, and provides recommendations to prevent fraudulent insurance in this context. It is possible to solve the problem of fraudulently insured and ensure the sustainability of the Turkish social security system with regulations to be made in the primary legislation, public policies and practices that raise awareness for insured persons, automation regulations, and more supervision.

Two-step modification of pullulanase and transglucosidase: A novel way to improve the gel strength and reduce the digestibility of rice starch

The multiscale structure, gel strength and digestibility of rice starch modified by the two-step modification of pullulanase (PUL) pretreatment and transglucosidase (TG) treatment for 6, 12, 18 and 24 h were investigated. The debranching hydrolysis of PUL produced some linear chains, which rearranged to form stable crystalline structures, reducing the digestible starch content, but weakening the gel strength. TG treatment connected some short chains to longer linear chains via α-1,6-glycosidic bonds, generating the structures of linear chain with fewer branches. The short branches promoted the interaction between starch molecules to form a more compact three-dimensional gel network structure, showing higher hardness and springiness. Moreover, these chains could form more stable crystals, reducing the digestible starch content, and the increase of branching degree inhibited digestive enzyme hydrolysis, reducing the digestion rate. The multiscale structure of starch tended to stabilize after TG treatment for 18 h, which could form a gel with stronger strength and lower digestibility than native starch gel. Therefore, the two-step modification of PUL and TG was an effective way to change the structure of rice starch to improve the gel strength and reduce the digestibility.

Spatial phylogenetics of grasses in the Southern Cone provides insights into ecology and evolution of the family in South America

AbstractIn this study, we explored the distributions of grass genera in the Southern Cone (SC) of South America, applying several phylogenetic diversity (PD) metrics and randomization tests. Grasses appear to have been present in South America since their early evolution as tropical understory species more than 60 Ma. During the course of evolution, grasses have adapted to all terrestrial biomes and become one of the most successful plant families on earth. At present, the SC contains nearly all terrestrial biomes and a wide range of humid to arid ecoregions. Analyzing 126.514 point occurrences and four plastid markers for 148 genera (91% of the native grass genera), we found that tropical humid regions hold the highest PD, with no observed bias in branch lengths. These results indicate that niche conservatism dominates the diversity pattern of grasses in the SC. We found significantly low PD in the Dry Chaco and in the Patagonian Steppe, which suggest ecological filtering in both warm and cold arid regions. The Patagonian Steppe also holds significantly longer branches than expected by chance, as the native grass flora is mainly composed of distantly related Pooideae genera with a northern hemisphere origin. Short branches are found in the Uruguayan Savanna, suggesting that these grasslands could be a cradle for grass diversity within the SC. The dated phylogeny supported the current view of a relatively recent evolution of the family within the SC, with most diversification taking place from the middle Miocene and onwards.

Four new species and a ribosomal phylogeny of Rhabdopleura (Hemichordata: Graptolithina) from New Zealand, with a review and key to all described extant taxa.

All eight extant species ofRhabdopleuradescribed between 1869 and 2018 are provisionally accepted as valid based on a review of the literature and new data on two little-known species from the Azores. Additionally, four new species are described from the New Zealand region, increasing global diversity by 50%, and a dichotomous key to all 12 described species is provided based on morphological criteria. The distinction between colony morphologies based on erect-tube inception is regarded as particularly helpful in initial characterization of species. Erect ringed tubes are either produced directly from the surface of creeping-tubes or indirectly, i.e. a short adherent side branch from a creeping tube is interpolated between the creeping tube and an erect tube; such side branches are blind-ending. These two modes of erect-tube origination are here respectively termeddirectandindirect. Species with indirect erect-tube budding are predominant in the North Atlantic whereas species with direct erect-tube budding dominate in New Zealand waters. The only indirect-erect species from New Zealand, Rhabdopleura chathamica n. sp., was discovered on deepwater coral from 10081075 m, constituting the deepest record of the genus to date. Rhabdopleura emancipata n. sp., collected only in a detached state, constitutes a three-dimensional tangled growth that grew freely into the water columna unique morphology hitherto unknown among extant species. Owing to this growth mode, it provided a substratum for epibionts from several phyla. Rhabdopleura francesca n. sp. and Rhabdopleura decipula n. sp. are morphologically very similar but are distinguishable by their distinct placements in a phylogeny based on 16S mitochondrial and 18S nuclear rRNA genes. Phylogenetic reconstructions based on rRNA and mitochondrial genome data contribute to an updated phylogeny of all Rhabdopleura species sequenced thus far, some of which require more molecular sequences and morphological analyses for taxonomic determination.

Unraveling the Myotis morass: ultraconserved-element analysis reveals introgression, cryptic diversity, and taxonomic trouble

Abstract Using sequences from 2,615 ultraconserved element (UCE) loci and multiple methodologies we inferred phylogenies for the largest genetic data set of New World bats in the genus Myotis to date. The resulting phylogenetic trees were populated with short branch lengths and widespread conflict, hallmarks consistent with rapid adaptive radiations. The degree of conflict observed in Myotis has likely contributed to difficulties disentangling deeper evolutionary relationships. Unlike earlier phylogenies based on 1 to 2 gene sequences, this UCE data set places M. brandtii outside the New World clades. Introgression testing of a small subset of our samples revealed evidence of historical but not contemporary gene flow, suggesting that hybridization occurs less frequently in the Neotropics than the Nearctic. We identified several instances of cryptic lineages within described species as well as several instances of potential taxonomic oversplitting. Evidence from Central and South American localities suggests that diversity in those regions is not fully characterized. In light of the accumulated evidence of the evolutionary complexity in Myotis and our survey of the taxonomic implications from our phylogenies, it is apparent that the definition of species and regime of species delimitation need to be reevaluated for Myotis. This will require substantial collaboration and sample sharing between geneticists and taxonomists to build a system that is both robust and applicable in a genus as diverse as Myotis.

Microvascular Network Remodeling in the Ischemic Mouse Brain Defined by Light Sheet Microscopy.

Until now, the analysis of microvascular networks in the reperfused ischemic brain has been limited due to tissue transparency challenges. Using light sheet microscopy, we assessed microvascular network remodeling in the striatum from 3 hours to 56 days post-ischemia in 2 mouse models of transient middle cerebral artery occlusion lasting 20 or 40 minutes, resulting in mild ischemic brain injury or brain infarction, respectively. We also examined the effect of a clinically applicable S1P (sphingosine-1-phosphate) analog, FTY720 (fingolimod), on microvascular network remodeling. Over 56 days, we observed progressive microvascular degeneration in the reperfused striatum, that is, the lesion core, which was followed by robust angiogenesis after mild ischemic injury induced by 20-minute middle cerebral artery occlusion. However, more severe ischemic injury elicited by 40-minute middle cerebral artery occlusion resulted in incomplete microvascular remodeling. In both cases, microvascular networks did not return to their preischemic state but displayed a chronically altered pattern characterized by higher branching point density, shorter branches, higher unconnected branch density, and lower tortuosity, indicating enhanced network connectivity. FTY720 effectively increased microvascular length density, branching point density, and volume density in both models, indicating an angiogenic effect of this drug. Utilizing light sheet microscopy together with automated image analysis, we characterized microvascular remodeling in the ischemic lesion core in unprecedented detail. This technology will significantly advance our understanding of microvascular restorative processes and pave the way for novel treatment developments in the stroke field.

An assessment of methods to combine evolutionary history and conservation: A case study in the Brazilian campo rupestre.

Conservation policies typically focus on biodiversity hotspots. An alternative approach involves analyzing the evolutionary history of lineages in geographic areas along with their threat levels to guide conservation efforts. Mountains exhibit high levels of plant species richness and micro-endemism, and biogeographic studies commonly point to recent and rapid evolutionary radiations in these areas. Using a nearly endemic clade of legumes, our study evaluates conservation prioritization approaches in the campo rupestre, a Neotropical ecosystem associated with mountaintops that is located between two biodiversity hotspots. We compared the EDGE and EDGE2 metrics, which combine the evolutionary distinctiveness and the extinction risk of a species in a single value. These metrics are compared with traditional metrics used to assess conservation priority, such as phylogenetic diversity. The EDGE values reported are lower than those of other studies using this metric, mostly due to the prevalence of threatened species with short phylogenetic branch lengths (low values of evolutionary distinctiveness). Certain areas of campo rupestre with relatively high phylogenetic diversity and EDGE values do not correspond to areas with high species richness, agreeing with previous studies on biodiversity hotspots. Our study highlights the necessity of conservation of the campo rupestres as well as advantages and disadvantages of using EDGE, EDGE2, and phylogenetic diversity for appropriate selection of conservation areas with rapid evolutionary radiations. The selection of the metrics will depend primarily on the life history of the focus group and the data availability, as well as the conservation approach.

Fault Coalescence, Slip Distribution, and Stress Drop of the February 2023 Southeast Türkiye Earthquakes from Joint Inversion of SAR, GNSS, and Burst Overlap Interferometry

Abstract Two devastating earthquakes struck southeastern Türkiye and northwestern Syria on 6 February 2023: an Mw 7.8 mainshock, followed 9 hr later by an Mw 7.6 aftershock. To recover and separate the subsurface geometry and slip distributions along the two earthquake faults, we jointly invert Interferometric Synthetic Aperture Radar, Synthetic Aperture Radar pixel offset tracking, burst overlap interferometry (BOI), Global Navigation Satellite System, and aftershock datasets. We introduce a new Kalman filter-based approach for merging spatially dense azimuth offset (AZO) data with the more precise yet spatially sparse BOI data. This procedure yields improved measurements of the displacements parallel to the near north-south satellite tracks, which are critical for resolving slip along most of the Mw 7.8 fault segments. We optimize the inversion using a new metric for assessing the degree of spatial correlation between the coseismic slip gradients and early aftershocks, resulting in a stable solution honoring the complementarity between the geodetic and aftershock datasets. The analysis suggests that the Mw 7.8 rupture consisted of three large segments and two short fault branches, covering about 300 km along the East Anatolian fault (EAF), whereas the Mw 7.6 rupture consisted of three segments extending for about 160 km along the nearby Sürgü fault (SF). On the basis of moment-to-stress-drop scaling relations, we show that the Mw 7.6 stress drop is four times larger than the Mw 7.8 stress drop, consistent with the larger recurrence intervals for Mw > 7 earthquakes on the SF than on the EAF. The moment released during the 2023 Mw 7.8 earthquake is 2–4 times larger than the sum of the moments released during individual historical Mw > 7 earthquakes along the three segments of the 2023 Mw 7.8 earthquake. Thus, when considering moment release for multisegment earthquakes, one should note that the final moment of fault coalescence is likely larger than the arithmetic sum of individual segment ruptures.