Labile Structures Research Articles

Universal features in the lifetime distribution of clusters in hydrogen-bonding liquids.

Hydrogen-bonding liquids, typically water and alcohols, are known to form labile structures (network, chains, etc.); hence, the lifetime of these structures is an important microscopic parameter, which can be calculated via computer simulations. Since these cluster entities are mostly statistical in nature, one would expect that, in the short-timescale regime, their lifetime distribution would be a broad Gaussian-like function of time, with a single maximum representing their mean lifetime, and be weakly dependent on criteria such as the bonding distance and angle, much similar to non-hydrogen-bonding simple liquids, while the long-timescale regime is known to have some power law dependence. Unexpectedly, all the hydrogen-bonding liquids studied herein, namely water and alcohols, display three highly hierarchical specific lifetimes, in the sub-picosecond range 0-0.5 ps. The dominant lifetime depends very strongly on the bonding-distance criterion and is related to hydrogen-bonded pairs. This mode is absent in non-H-bonding simple liquids. The secondary and tertiary mean lifetimes are related to clusters and are nearly independent of the bonding criterion. Of these two lifetimes, only the first one can be related to that of simple liquids, which poses the question of the nature of the third lifetime. The study of alcohols reveals that this third lifetime is related to the topology of the H-bonded clusters and that its distribution may also be affected by the alkyl tail surrounding the "bath". This study shows that hydrogen-bonding liquids have a universal hierarchy of hydrogen-bonding lifetimes with a timescale regularity across very different types, and which depend on the topology of the cluster structures.

Biochar and hydrochar derived from freshwater sludge: Characterization and possible applications

Freshwater sludge (FS) is generated in large quantities during the production of drinking water every day. It is largely underutilized, and has long been filter pressed to sludge cake and then disposed of in landfills. The search for more economical and sustainable disposal or reuse options is urgently needed. Biochar and hydrochar are increasingly popular wastes derived materials with huge potential for soil improvement, environmental remediation, and mitigation of climate change, but there is a lack of research on the production of FS derived biochar and hydrochar. In this study, biochar was produced by pyrolysis at 300, 500 or 700 °C for 1 h, and hydrochar was produced by hydrothermal carbonization (HTC) at 140, 160, 180 or 200 °C for 4 h. Proximate analyses show that the biochar has a higher carbon stability and is possibly suitable for carbon sequestration, while the hydrochar contains more labile carbon structures. The ultimate analysis indicates that the surface hydrophobicity is in the order of: biochar > hydrochar > FS. The phytotoxicity tests indicate their positive effects on germination of wheat seeds. This study provides a new treatment to reuse numerous FS and put forward the possible applications of its carbonaceous products, which is expected to facilitate a circular economy and realize the zero-waste target.

Labile anticausatives in Jordanian Arabic

AbstractThis study examines the morpho-syntax of labile anticausative structures in Jordanian Arabic (JA). Although the transitive counterpart of anticausatives is marked via morphological affixes that reflect structural and lexical components in Classical Arabic and Modern Standard Arabic, a number of verbs involving causative alternation exhibit identical forms in JA (e.g.,ġala[+T] ‘to CAUSE boil something’ vsġala[–T] ‘to BECOME boil’). Such variation poses challenges for mapping between verb morphology and its lexical semantics. To handle such variation, which is also observed cross-linguistically, we argue in favour of Schäfer (2008; 2012), Schäfer & Vivanco (2015), and Ramchand’s (2008) “causer-less” analysis over Koontz-Garboden’s (2009) “reflexive” analysis. This work further assumes the existence of a Voice phrase lacking a specifier (external argument) and assumes that Voice projection is headed by an implied Voice head (vcauser) that syntactically assigns the accusative case to its new subject and semantically encodes the internal argument and describes the resultant subevent of the verb. The work also provides an alternative solution for voice projection that lacks an explicit specifier bearing [+agent] or [+causer] feature specification. The work assumes the presence of an inchoative Voice head [vinch] introducing the Spec Voice Phrase, which encodes an inchoative resultant state of an event achieved over its theme. Contrary to Al-Qadi (2015), the present model assumes that such verbs constitute a middle position between transitive and intransitive verbs in JA but do not constitute a separate class of their own. Evidently, the correct characterization of the anticausative subclass distribution is that it surfaces wherever v is transitive as well as in intransitive volitional contexts (a non-natural class). More intriguingly, the presented material suggests that there is an ongoing process of diachronic change in spoken Arabic varieties (including JA) that amounts to the development and expansion of an inchoative class where no external or internal inchoative detransitivizing morphemes are involved. This topic, which incorporates an intriguing diachronic dimension in addition to the syntactic details, is missing from the generative literature on Arabic morpho-syntax and is potentially of sufficient interest to merit investigation.

Surface-Directed Disparity in Self-Assembled Structures of Small-Peptide l-Glutathione on Gold and Silver Nanoparticles.

Despite the key roles of l-glutathiones (GSHs) inbiology and nano-biotechnology, understanding their labile structures and hydrogen bond interactions with nanoparticles has posed a critical challenge to the scientific community. The structural conformation of GSH as a capping layer on gold nanoparticle (AuNP) and silver nanoparticle (AgNP) surfaces is investigated. In this report, we attempt to explore the material-dependent interaction of GSH with different spherical nanoparticle surfaces by employing Fourier transform infrared (FTIR) spectroscopy. The infrared signal of amide I of GSH is studied as a function of different materials' spherical nanoparticles with comparable size. We revealed the β-sheet secondary structure of GSH on AgNPs and the random structure on AuNPs even though both the nanoparticles have comparable shapes and sizes and belong to the same group of the periodic table. The GSH is firmly anchored on the gold and silver surface via the thiol of the cys part. However, our experimental data designate a further interaction with the AgNP surface via the carboxylic acid group of the gly- and glu- end of the molecule. It is observed that enhancement of IR absorption of amide I of GSH is pronounced by a factor of 10 on AuNP but, in contrast, on the same-sized AgNP, the suppression is perceived by a factor of 2, even though both are plasmonic materials with respect to free GSH. This study can be used as a point of reference for understanding the structural conformation of the capping layer on nanoparticle surfaces as well as surface enhancement of the IR absorption of amide I. We would like to emphasize that molecular self-assembly on the nanoparticle surfaces is definitely of very broad interest for chemists working in nearly any subdiscipline, spanning from the nanoparticle-based medicine to surface-enhanced spectroscopy to heterogeneous catalysis, etc.

Fire lead to disturbance on organic carbon under sugarcane cultivation but is recovered by amendment with vinasse

Sugarcane burning has been widely practiced in Brazil and worldwide. In the long term, this farming practice can cause soil erosion, reduction in organic carbon (OC) and consequently, changes in the structure of soil organic matter (SOM). Such changes may be difficult to reverse. This study aimed to assess the medium- and long-term effects of sugarcane burning on SOM characteristics, both in terms of quantity and structural quality and evaluate the application of vinasse as a strategy to attenuate fire-induced changes in burned soil. The experiment was conducted in a 50-year-old sugarcane field on soils classed as Cambissolo Háplico (Inceptisol). Four plots were sampled: a) burning of sugarcane for harvest for 37 years (SCB37); b) renewal of the sugarcane field and burning for harvest for 3 years (SCB3); c) renewal of the sugarcane field without burning for harvest for 3 years (SCWB), and d) renewal of the sugarcane field and burning for harvest with the application of vinasse for 3 years (SCV). Chemical and physical characterization of SOM was performed by solid-state spectroscopy (UV–vis, ATR-FTIR e 13C NMR CP/MAS) and chemometric techniques. The results showed that sugarcane burning drastically impacts SOM content and its chemical structure, however, the application of vinasse preserves and restores the soil from the fire effects. Content of soil OC, particulate OC, mineral-associated OC, humic acid, humin and light fraction OM that were affected by fire, had an increase and recovery of contents by the vinasse application. Solid state spectroscopy showed that labile structures were lost in humic acids (HA) by fire and recalcitrant structures were preserved. The application of vinasse incorporated fragments of lipids and carbohydrates in HA structure. Burning sugar cane straw affects the integrity of soil organic matter but can be restored by applying vinasse.

Structure–Property–Function Relationship of Humic Substances in Modulating the Root Growth of Plants: A Review

The structural identity of humic substances (HS) in the soil is a highly debated issue in the soil sciences. Although the complexity and structural characteristics that determine the functions of HS justify their further study, there is enough scientific evidence explaining the presence of these compounds as a group of structures that are formed by humification and have unique chemical characteristics. This review presents scientific information that follows the structure–property–function relationship with the objective of better explaining the nature of HS. On the basis of the spectroscopic characterization of a number of humic acids, together with the use of chemometric techniques, it is shown that, although the sources of origin are different, HS have a unique structural pattern that is different from that of any other group of soil compounds. From this structural pattern, it is possible to understand how fragments with greater lability in HS can reach root surfaces and interact with the cell membrane, regulate oxidative metabolism, and stimulate root growth in plants. Lability and recalcitrance are properties arising from the characteristics and suprastructural organization of HS and can define the type and intensity of the bioactivity of HS in plants. In this review, we demonstrate that there are methods for studying HS by which a deeper understanding of the functions of these substances on the basis of their chemical properties is possible. Therefore, the understanding of this complex system allows the connection of the scientific elements that justify the existence of these compounds in the soil.Core Ideas Humic substances have an unequivocal and characteristic structural pattern. Characterization combined with chemometrics allows the study of humic substance function. Humic substances in the rhizosphere establish chemical interactions with plant roots. Humic substances modulate reactive oxygen species and enzymatic activity in plants. Labile structures in the humic suprastructure are related to plant root growth.

Different Structures in Humic Substances Lead to Impaired Germination but Increased Protection against Saline Stress in Corn

ABSTRACTThe effects of humic substances (HS) on plants are related to humic structure. The present study aimed to characterize HS different origins and to evaluate the effects on germination and protective effects against salt stress in corn. HS were extracted from an Andosol -Ecuador (HSAnd), Histosol -Brazil (HSHist) and vermicompost (HSVc) and characterized by 13C-NMR CP/MAS combined to chemometric analyzes. Germination indexes and metabolic parameters were used to evaluate the effects of HS on corn plants. Two types of experiments were performed, both with a completely randomized experimental design and twenty-five replicates per treatment. The results show that HSAnd are predominantly more aromatic and low polarity. The HSHist and HSVc were less aromatic and had higher polarities. None of the tested HS stimulated corn seed germination and HSAnd had more pronounced negative effects. Protective effects of HS were related to different structures. Labile structures were related to plant growth and more aromatic structures affected the plant’s pigment production. The humic structural balance increases HS bioactivity and protective effects more than a specific type of structure. The present results are important for agriculture because maintaining HS with adequate structural quality in soils may protect plants from eventual periods of high salinity.

Vibrational Coupling on Stepwise Hydrogen Bond Formation of Amide I.

Despite the key roles of proteins and nucleic acids in biology, understanding their labile structures and hydrogen bond interactions with guest molecules has posed a critical challenge to the scientific community. In this report, I have used dimethylformamide as a model amide to account for amide hydrogen bond interactions of protein. To quantify hydrogen bond conformation and the structural change, I have monitored the amide I infrared (IR) stretching frequencies while varying the pKa of phenol derivatives. For all phenol derivatives, amide I has formed one hydrogen bond and two hydrogen bond conformation. It has been observed that the formation constant for one hydrogen bond is higher than that of two hydrogen bonds for all phenol derivatives. During the formation of hydrogen bond with amide I, IR absorbance of C═C transition is enhanced for all phenol derivatives. Enhancement of the IR absorbance of the C═C transition indicates hydrogen bond-assisted vibrational coupling between the amide I and phenol ring transition. The relative coupling constant is estimated to be higher for single hydrogen-bonded conformer than the double hydrogen-bonded conformer. This is an intriguing result as the frequency difference between the two coupled transitions predicts otherwise. Using IR absorption spectroscopy, a delicate interplay between hydrogen bonding conformations and intermolecular vibrational coupling between amide I and H-bond donor phenol molecules has been shown. This study can be used as a point of reference for understanding the structural information of proteins, peptides, and nucleosides having hydrogen bond interaction with any drug or ligand molecules. My results as well provide an insight into the vibrational coupling of carbonyl and C═C transition of nucleobases.

Characterization of protein extracts from different types of human teeth and insight in biomineralization

The present study describes an efficient method for isolation and purification of protein extracts from four types of human teeth i.e. molar, premolar, canine, and incisor. Detailed structural characterization of these protein extracts was done by Fourier transform infrared spectroscopy (FTIR) and circular dichroism (CD) which showed that a major fraction of the proteins present are unstructured in nature including primarily random coils in addition to the other structures like extended beta (β) structure, poly-l-proline-type II (PPII) helix, turns, with only a small fraction constituting of ordered structures like alpha (α) helix and β sheets. These resultant labile structures give the proteins the necessary flexibility that they require to interact with a variety of substrates including different ions like calcium and phosphates and for other protein-protein interactions. We also did initial studies on the mineralization of calcium phosphate with the protein extracts. Nanoparticle tracking analysis (NTA) show an increase in the size of calcium phosphate accumulation in the presence of protein extracts. We propose that protein extracts elevate the crystallization process of calcium phosphate. Our current biophysical study provides novel insights into the structural characterization of proteins from human teeth and their implications in understanding the tooth biomineralization. As per our knowledge, this is the first report which focuses on the whole protein extraction from different types of human teeth as these extracts imitate the in vivo tooth mineralization.

Relation between changes in organic matter structure of poultry litter and heavy metals solubility during composting

Poultry litter (PL) is widely used as fertilizer because of its rich N, P and Ca content. When PL is applied to previously untreated soil, it is a potential contaminant. Composting is an alternative for stabilizing organic and mineral components. This study aimed to elucidate the structural changes and its influence on the solubility of heavy metals in poultry litter during the first 30 d of composting, which is the period when the most intense transformations occur. For this analysis, the transformation dynamics of the organic structures and the availability of mineral elements were studied via spectroscopic characterization, total heavy metal content determination and chemical fractionation at three composting times (0, 15, and 30 d). During composting, the material's aromaticity increased, while its aliphaticity decreased, and the hydrophobicity index increased as the polarity decreased. These results indicate that during the first 30 d, PL composting occurs via transformation of the most labile structures (carbohydrate, peptide and fatty acid fragments), thereby preserving the most stable and least functionalized structures. Composting increased the concentrations of Cu, Cr, Pb and Zn and the transformation of CAlk-O and CAlk-di-O associated with peptides and carbohydrates and favored solubilizing and leaching a water-soluble fraction rich in these compounds. The labile fractions of Fe and the humified organic matter fractions of Cu, Fe, Mn, Zn, and Al increased. The structural changes reduced heavy metal solubility, thus indicating that after 30 d of composting, the heavy metal contamination risk is low.

Geometric morphometrics approach towards discrimination of three member species of Maculatus group in Thailand

Members of the Maculatus group are important malaria vectors in the border regions of Thailand. However, the role of each species in malaria transmission remains unclear because of their highly similar morphologies, making them difficult to be differentiated. Whereas An. pseudowillmori may be identified by the color pattern of some scales on abdomen and wings, the distinction between An. maculatus and An. sawadwongporni relies on the wings only. Scales are labile structures, as they may be accidentally removed during capture and transportation to the laboratory. To discriminate among the species of this group, we tested the suitability of geometric techniques. Shape variables were used as input for discriminant analyses and validated reclassification. Both landmark- and outline-based geometric techniques disclosed significant differences between the three species. For the delicate An. maculatus - An. sawadwongporni distinction, the outline-based approach appeared as the most promising, with validated reclassification scores reaching 93%, as compared to 77% obtained by landmark data. For An. pseudowillmori, reclassification scores were 100% and 94%, respectively. Geometric morphometrics may provide an alternative and useful complement for discriminating members of the Maculatus group.

Throwing light on an uncommon preservation of Blattodea from the Crato Formation (Araripe Basin, Cretaceous), Brazil

Fossilization results from several physical-chemical-geological processes. Original labile and non-bioclastic structures rarely survive throughout this process. In particular, the Crato Formation (Araripe Basin) is one of the most significant Cretaceous Konservat- Lagerstatten due to its well-preserved invertebrates, mainly three-dimensional insects. In general, Crato insects exhibit brown-orange color, constituted by goethite or hematite replacements. In this context, we used the scanning electron microscopy coupled to energy dispersive spectrometer and Raman spectroscopy to analyze Araripeblatta dornellesae, a 115 million-years-old fossil from Crato Formation, Araripe Basin. Our results show that a dark-color material rather than the brown-orange pattern preserve this specimen. The carbon is restricted to the fossil imprint, indicating some retention of the original organic remains. In addition, the presence of original organic components allowed to approach the biochemical aspects further than simple morphology, as well as to elucidate the taphonomical complexity involved in this preservation style.

Transformation of Trioctahedral Mica in the Upper Mineral Horizon of Podzolic Soil during the Two-Year-Long Field Experiment

An experiment on transformation of biotite (fraction <1 μm) particles placed into containers with different permeability in the AEL horizon of podzolic soil was performed in order to estimate the contribution of different factors to the transformation of biotite in the modern soil. After two-year-long incubation in the AEL horizon, biotite was transformed into vermiculite, mixed-layer biotite–vermiculite, and pedogenic chlorite. The most intense vermiculitization of the biotite took place under the impact of fungal hyphae and, to a lower degree, fine plant roots and components of the soil solution. The formation of labile structures from biotite was accompanied by thinning of the mica crystallites, the disturbance of the homogeneity of layers, the removal of interlayer K, the removal and oxidation of octahedral Fe, the increase in the sum of exchangeable cations, and the appearance of exchangeable Al. The process of chloritization was definitely diagnosed upon the action of plant roots and fungal hyphae on the biotite. Strong complexing anions released by fungal hyphae partly inhibited chloritization. Chloritization led to a decrease in the cation exchange capacity of vermiculitic structures.

Molecular structure of muscle filaments determined by electron microscopy.

Electron microscopy and X-ray diffraction have together played a key role in our understanding of the molecular structure and mechanism of contraction of muscle. This review highlights the role of electron microscopy, from early insights into thick and thin filament structure by negative staining, to studies of single myosin molecule structure, and finally to recent high-resolution structures by cryo-electron microscopy. Muscle filaments are designed for movement. Their labile structures thus present challenges to obtaining near-atomic detail, which are also discussed.

Targeted MultiNotch MS3 Approach for Relative Quantification of N-Glycans Using Multiplexed Carbonyl-Reactive Isobaric Tags.

The recently developed and commercially available carbonyl-reactive tandem mass tags (aminoxyTMT) enable multiplexed quantification of glycans through comparison of reporter ion intensities. However, challenges still exist for collision activated dissociation (CAD) MS/MS based quantification of aminoxyTMT due to the relatively low reporter ion yield especially for glycans with labile structures. To circumvent this limitation, we utilized the unique structural features of N-glycan molecules, the common core sugar sequence (HexNAc)2(Man)3, and common m/z of Yn ions generated from different types of precursors by MS/MS and designed a Y1 ion triggered, targeted MultiNotch MS3 relative quantification approach based on aminoxyTMT labeling. This approach was implemented on a nanoHILIC-Tribrid quadrupole-ion trap-Orbitrap platform, which enables prescreening of aminoxyTMT labeled N-glycan precursor ions by Y1 ion fragment ion mass in a higher-energy collisional dissociation (HCD) MS/MS scan and coisolation and cofragmentation of multiple Yn fragment ions that carry the isobaric tags from the inclusion list in the MS/MS/MS scan. Through systematical optimization and evaluation using N-glycans released from several glycoprotein standards and human serum proteins, we demonstrated that the Y1 ion triggered, targeted MultiNotch MS3 approach offers improved accuracy, precision, and sensitivity for relative quantification compared to traditional data-dependent MS2 and Y1 ion MS3 quantification methods.

The Effect of Treatment with Hydrogen Peroxide and the Mehra–Jackson Reagent on X-ray Diffraction Patterns of Clay Fractions

X-ray diffraction patterns of clay fractions from the AEL and EL horizons of pale-podzolic soil before and after treatment with 10% H2O2 and the Mehra–Jackson reagent in different sequences have been examined. The successive treatment with 10% H2O2 and then with the Mehra–Jackson reagent causes dissolution of Al-hydroxy-interlayers in pedogenic chlorites and the respective increase in the content of labile minerals because of a dramatic decrease in pH upon the treatment with hydrogen peroxide. The rate of these changes depends on the degree of chloritization of pedogenic chlorites in the initial samples. The result of the reverse sequence of the treatments of clay fractions (initially with the Mehra–Jackson reagent and then with hydrogen peroxide) is opposite: the chloritization of labile minerals becomes more intensive. It is provided by pH values that do not drop below 7.5 at any treatment stage. At particular stages, pH values favors the mobilization of Al compounds and their subsequent polymerization in the interlayer space of labile structures. We suppose that hydroxyl-aluminosilicate layers may be formed in the interlayer space upon this treatment sequence.

Effect of tacticity and molecular weight on the rheological properties of poly(N-isopropylacrylamide) gels in benzyl alcohol

Two series of different isotactic poly(N-isopropylacrylamide) of number average molar masses (Mn) ∼ 100 000, 200 000 and narrow molar mass distribution are prepared by reversible addition fragmentation chain transfer polymerization. Their thermoreversible, physical gels are prepared in benzyl alcohol and rheologically characterized to assess the effect of tacticity and molar masses on the rheological properties. In general, higher tacticity, higher molar mass, and higher concentration lead to stiffer gels and a sol-gel transition at a higher temperature. The results are interpreted based on partial phase separation leading to stiff but labile spongelike structures. The tacticity influences the strength of the phase separation tendency. Concentration and molar mass determine how far reaching and how connected these domains are.

Soil organic matter in podzol horizons of the Amazon region: Humification, recalcitrance, and dating

Characteristics of soil organic matter (SOM) are important, especially in the Amazon region, which represents one of the world's most relevant carbon reservoirs. In this work, the concentrations of carbon and differences in its composition (humification indexes) were evaluated and compared for several horizons (0 to 390cm) of three typical Amazonian podzol profiles. Fluorescence spectroscopy was used to investigate the humic acid (HA) fractions of SOM isolated from the different samples. Simple and labile carbon structures appeared to be accumulated in surface horizons, while more complex humified compounds were leached and accumulated in intermediate and deeper Bh horizons. The results suggested that the humic acids originated from lignin and its derivatives, and that lignin could accumulate in some Bh horizons. The HA present in deeper Bh horizons appeared to originate from different formation pathways, since these horizons showed different compositions. There were significant compositional changes of HA with depth, with four types of organic matter: recalcitrant, humified, and old dating; labile and young dating; humified and young dating; and little humified and old dating. Therefore, the humification process had no direct relation with the age of the organic matter in the Amazonian podzols.

The Effect Of microbial Mats In The Decay Of Anurans With Implications For Understanding Taphonomic Processes In The Fossil Record

The pattern and sequence of the decomposition of the Pipidae African dwarf frog (Hymenochirus boettgeri) is tracked in an experiment with microbial mats in order to explore soft tissue preservation over three years. Frog decay in microbial mats is preceded by rapid entombment (25–30 days) and mediated by the formation of a sarcophagus, which is built by a complex microbial community. The frog carcasses maintained a variety of soft tissues for years. Labile organic structures show greater durability within the mat, cells maintain their general shape (bone marrow cells and adipocytes), and muscles and connective tissues (adipose and fibrous tendons) exhibit their original organic structures. In addition, other soft tissues are promptly mineralized (day 540) in a Ca-rich carbonate phase (encephalic tectum) or enriched in sulphur residues (integumentary system). The result is coherent with a bias in soft-tissue preservation, as some tissues are more likely to be conserved than others. The outcomes support observations of exceptionally preserved fossil anurans (adults and tadpoles). Decomposition in mats shows singular conditions of pH and dissolved oxygen. Mineralization processes could be more diverse than in simple heterotrophic biofilms, opening new taphonomic processes that have yet to be explored.

CONSANGUINITY BY RANDOM ISONYMY AND SOCIOECONOMIC DEVELOPMENT IN ARGENTINA: A POPULATION STUDY.

In human populations various flexible, labile and interdependent structures (genetic, demographic, socioeconomic) co-exist, each of which can be organized in an hierarchical order corresponding to administrative entities. The relationship between consanguinity, as estimated by random isonymy (F ST), and socioeconomic conditions was analysed at different levels of political and administrative organization in Argentina. From the surnames of 22,666,139 voters from the 2001 electoral roll, F ST was estimated for 510 Argentinian departments. Using a principal component analysis, a Socio-Demographic and Economic Indicator (SDEI), summarizing the effect of 22 socioeconomic and demographic variables at the departmental level, was computed. The relationship between departmental F ST and SDEI values was analysed for the whole nation and within regions using multiple regression analysis. The F ST presented a clinal distribution with the highest values in the north and west of the country, while SDEI expressed the opposite behaviour. A negative and significant correlation was observed between F ST and SDEI, accounting for 46% of the variation in consanguinity in Argentina. The strongest correlations of F ST with SDEI were observed in the Central, Patagonia and Cuyo regions, i.e. those with the highest values of SDEI and lowest values of F ST.