Modern-day Distribution Research Articles

Detection of Bad Data and Estimation of Missing Parameter Values Using System Synergism

Communication infrastructure is paramount for the optimal control and protection of modern-day distribution systems. However, inherent problems associated with the communication systems such as loss of data packets due to excessive latency and erroneous signal induction result in impairment of the network control and relaying signals. In the present article, a method based on Data Mining is proposed for the detection of Bad/Noisy data. Furthermore, the concept of system synergism is utilized to estimate the value of the signal in which Bad Data is detected. In case of Bad measurements during faults/ transients or load switching, the estimates are observed using Machine Learning (ML) based regression model. XGboost has been found to have the best performance among the ML models. Modbus is considered the communication protocol for the power distribution system under the consideration. Test results are demonstrated using a standard IEEE 33 bus test system. The feasibility of the proposed algorithm in real-time is confirmed using the raspberry pi 3B+ controller using Serial Peripheral Interface (SPI) protocol.

Hydroclimate variations over the last 17,000 years as estimated by leaf waxes in rodent middens from the south-central Atacama Desert, Chile

Leaf cuticular waxes are one of the most important environment-plant interaction structural systems that enable desert plants to withstand extreme climatic conditions. We present a long chain n-alkyl lipids study in fresh plant leaves and rodent palaeomiddens collected along an elevational gradient in the south-central Atacama Desert of Chile, covering six different vegetation belts: Steppe (4500-4000 m asl), Puna (4000-3300 m asl), pre-Puna (3300-2400 m asl), Absolute Desert (2400-1000 m asl) and Coastal Desert (1000-0 m asl). The 28 rodent palaeomiddens analyzed from Quebrada Incahuasi (25.6 °S, 3600 m asl) span the last 17,000 years. Modern-day distribution of long-chain n-alkanes and n-alkanoic acids varies among the dominant plant associations of the Atacama Desert. These plants show a species-specific chemotaxonomy linked to the climatic conditions. Furthermore, differences in average chain length (ACL) and carbon preference index (CPI) suggest that these plant communities are highly adapted to extreme environmental conditions. The sum of leaf wax n-alkanes was highest under wet conditions, while n-alkanoic acids (between n-C24 and n-C28) increased with hyperaridity. Similarly, analysis of n-alkane time series from palaeomiddens showed that the greatest changes in leaf wax n-alkane distributions (ACL and CPI) corresponded to the greatest increases in moisture during the Central Andean Pluvial Event (CAPE; between 18 and 9 ka cal BP) and the Late Holocene. The shift in the palaeomidden n-alkane distributions is corroborated by the relative abundance of rainfall-dependent extra-local taxa. This is the first study to report leaf wax content obtained from ancient rodent middens, and shows promising results as a robust hydroclimate proxy for the Atacama Desert region.

The extinction of Miocene broad-leaved deciduous Nothofagaceae and loss of seasonal forest biomes in New Zealand

Quantitative leaf mass per area reconstructions and prevalence of plicate vernation in broad-leaved Nothofagaceae fossils reveal that deciduousness was common in the middle to late Miocene of New Zealand. This functional type was subsequently lost, as modern-day New Zealand Nothofagaceae have small leaves that live for at least a year. Moreover, fully deciduous trees across all plant families are rare in the current New Zealand flora. Based on modern-day distribution in the Southern Hemisphere, broad-leaved deciduous Nothofagaceae occupy regions with consistently large seasonal differences in precipitation and cloud cover, relative to other functional types in the family (evergreen, small-leaved). Specifically, broad-leaved deciduous Nothofagaceae are in leaf in summer when cloud cover and precipitation are low, but are leafless in winter when cloud cover and precipitation is high. Notably, the seasonal difference in precipitation and cloud cover are more important in explaining deciduousness in Nothofagaceae than winter temperatures. Therefore, potential summer photosynthetic gains likely determine deciduousness in Nothofagaceae. Miocene palaeoclimate reconstructions reveal that New Zealand broad-leaved deciduous Nothofagaceae also thrived in a climate with larger seasonal precipitation differences than today, in an overall warmer climate. We suggest that deciduous Nothofagaceae in the New Zealand flora went extinct as the global climate cooled and summer photosynthetic gains diminished, as summers became progressively rainier and cloudier, favoring an evergreen habit.

Design and Analysis of ANFIS – Based MPPT Method for Solar Photovoltaic Applications

The solar photovoltaic energy is becoming popular in the modern-day distribution networks due to the clean energy factor. The photovoltaic modules exhibit a nonlinearity in the output power concerning the environmental conditions. This work suggests an adaptive neuro-fuzzy inference system- (ANFIS-) based maximal power point tracker (MPPT) for the optimization of the solar photovoltaic system (SPVS). The controller modelled is utilized to optimize the output power of a DC-DC converter connected to a 400 W PV array. The entire model is analysed employing MATLAB/SIMULINK using primary features provided by the technical data. The behavior of the controller modelled is tested for various weather conditions and partial shading conditions. The findings show the controller’s tracking speed effectiveness and dynamic response in PSCs.

Phylogeny, Evolution, and Biogeography of the North American Trapdoor Spider Family Euctenizidae (Araneae: Mygalomorphae) and the Discovery of a New ‘Endangered Living Fossil’ Along California’s Central Coast

Abstract We report here the discovery of a remarkable new monotypic mygalomorph spider genus, known only from one geographical location along the central coast of California. The single relict species comprising Cryptocteniza kawtakn. gen. n. sp., is morphologically distinct and geographically isolated from other related genera, with its closest phylogenetic relatives found much further to the east in New Mexico and Arizona. Using a phylogenomic approach employing anchored hybrid enrichment, we reconstruct the evolutionary history of the family Euctenizidae Raven, 1985 to explore relationships among genera, affirmatively place previously undescribed taxa, explore rates of diversification, and reconstruct the group’s biogeography. A biogeographic analysis shows that extinction likely played a significant role in shaping the observed disjunct modern-day distribution of Cryptocteniza and its sister taxa. Our extinction hypothesis is further bolstered by a diversification rate analysis identifying considerably higher rates of speciation in other euctenizid lineages like AptostichusSimon, 1891. Consequently, changes in environmental conditions (or other related biotic and/or abiotic factors) may have spurred an adaptive radiation in related genera now widely distributed across the California Floristic Province biodiversity hotspot, with concomitant extinction in Cryptocteniza following the Miocene and establishment of a Mediterranean climate. Owing to its phylogenetic distinctiveness, incredibly narrow distribution and age, we show that Cryptocteniza meets all the criteria of an ‘Endangered Living Fossil’ and is consequently of grave conservation concern.

Evidence of an ancient connectivity and biogeodispersal of a bitterling species, Rhodeus notatus, across the Korean Peninsula

The modern-day distribution of freshwater fishes throughout multiple rivers is likely the result of past migration during times when currently separate drainages were once connected. Here, we used mitochondrial and microsatellite analyses for 248 individuals of Rhodeus notatus collected from seven different rivers to obtain better understand historical gene flow of freshwater fish on the Korean Peninsula. Based on our phylogenetic analyses, this Korean species originated through the paleo-Yellow River from China and first colonized near the west coast. These genetic data also provided evidence of estuary coalescences among the rivers flowing to the west and southwest coast on well-developed continental shelf. In addition, the pattern of population structure revealed the biogeodispersal route from the west coast to the south coast. It could be inferred that massive migration was not involved in the formation of southern populations, since the signature of historical genetic drift was clearly observed. Our study is the first genetic attempt to confirm hypotheses describing the migration of freshwater species towards the end of East Asia, which have previously been developed using only geological reasoning.

Geographic isolation and climatic variability contribute to genetic differentiation in fragmented populations of the long-lived subalpine conifer Pinus cembra L. in the western Alps

BackgroundGenetic processes shape the modern-day distribution of genetic variation within and between populations and can provide important insights into the underlying mechanisms of evolution. The resulting genetic variation is often unequally partitioned within species’ distribution range and especially large differences can manifest at the range limit, where population fragmentation and isolation play a crucial role in species survival. Despite several molecular studies investigating the genetic diversity and differentiation of European Alpine mountain forests, the climatic and demographic constrains which influence the genetic processes are often unknown. Here, we apply non-coding microsatellite markers to evaluate the sporadic peripheral and continuous populations of cembra pine (Pinus cembra L.), a long-lived conifer species that inhabits the subalpine treeline ecotone in the western Alps to investigate how the genetic processes contribute to the modern-day spatial distribution. Moreover, we corroborate our findings with paleoecological records, micro and macro-remains, to infer the species’ possible glacial refugia and expansion scenarios.ResultsFour genetically distinct groups were identified, with Bayesian and FST based approaches, across the range of the species, situated in the northern, inner and south-western Alps. We found that genetic differentiation is substantially higher in marginal populations than at the center of the range, and marginal stands are characterized by geographic and genetic isolation due to spatial segregation and restricted gene flow. Moreover, multiple matrix regression approaches revealed effects of climatic heterogeneity in species’ spatial genetic pattern. Also, population stability tests indicated that all populations had experienced a severe historical bottleneck, no heterozygosity excess was detected, suggesting that more recently population sizes have remained relatively stable.ConclusionsOur study demonstrated that cembra pine might have survived in multiple glacial refugia and subsequently recolonized the Alps by different routes. Modern-day marginal populations, at the edge of the species’ range, could maintain stable sizes over long periods without inbreeding depression and preserve high amounts of genetic variation. Moreover, our analyses indicate that climatic variability has played a major role in shaping differentiation, in addition to past historical events such as migration and demographic changes.

Controls on planktonic foraminifera apparent calcification depths for the northern equatorial Indian Ocean.

Within the world’s oceans, regionally distinct ecological niches develop due to differences in water temperature, nutrients, food availability, predation and light intensity. This results in differences in the vertical dispersion of planktonic foraminifera on the global scale. Understanding the controls on these modern-day distributions is important when using these organisms for paleoceanographic reconstructions. As such, this study constrains modern depth habitats for the northern equatorial Indian Ocean, for 14 planktonic foraminiferal species (G. ruber, G. elongatus, G. pyramidalis, G. rubescens, T. sacculifer, G. siphonifera, G. glutinata, N. dutertrei, G. bulloides, G. ungulata, P. obliquiloculata, G. menardii, G. hexagonus, G. scitula) using stable isotopic signatures (δ18O and δ13C) and Mg/Ca ratios. We evaluate two aspects of inferred depth habitats: (1) the significance of the apparent calcification depth (ACD) calculation method/equations and (2) regional species-specific ACD controls. Through a comparison with five global, (sub)tropical studies we found the choice of applied equation and δ18Osw significant and an important consideration when comparing with the published literature. The ACDs of the surface mixed layer and thermocline species show a tight clustering between 73–109 m water depth coinciding with the deep chlorophyll maximum (DCM). Furthermore, the ACDs for the sub-thermocline species are positioned relative to secondary peaks in the local primary production. We surmise that food source plays a key role in the relative living depths for the majority of the investigated planktonic foraminifera within this oligotrophic environment of the Maldives and elsewhere in the tropical oceans.

Radiocarbon dates of two musk ox vertebrae reveal ice-free conditions during late Marine Isotope Stage 3 in central South Norway

One of the most reliable proofs of terrestrial ice-free conditions within Stadials is the presence of terrestrial vertebrate fauna that require access to vegetation in the winter, for example sedentary birds such as Ptarmigans and herbivorous mammals in particular. The musk ox (Ovibos moschatus) is an example of the latter; modern-day distributions of this species are limited to areas with low snow accumulations. In this paper we discuss the discovery of musk ox bones in Norway. Recently obtained radiocarbon dates on this material demonstrate the presence of this species 41–35 cal kyr B.P. in southern Norway during late Marine Isotope Stage 3 (MIS3). Furthermore the dates have implications for the interpretation of climate and environmental conditions; indicating the existence of a small ice cap in the mountains and climate and vegetation supporting a large mammal fauna in South Norway at that time.

Constraining the applicability of organic paleotemperature proxies for the last 90 Myrs

We evaluated changes in the distributions of long-chain alkenones, long-chain diols and GDGTs, lipids commonly used for paleothermometry, over the last 90 Myrs for sediments deposited on the New Jersey shelf (the Bass River site) and assessed potential effects of different ancestral producers and diagenesis on their distributions and their impact on the associated temperature proxies. As reported before, the Paleogene distributions of alkenones are generally similar to those in modern haptophytes, but unusual alkenone distributions, characterized by a dominant di-unsaturated C40 alkenone, are observed for Late Cretaceous sediments, suggesting different ancestral source organisms for alkenones in this interval. The isoprenoid GDGT distributions remained comparable to modern-day distributions, suggesting that TEX86 can be applied up to ca. 90 Ma. The Miocene long-chain diol distributions are similar to modern-day distributions, but the older sediments reveal unusual distributions, dominated by the C28 1,12- and C26 1,13-diols, suggesting different source organisms before ∼30 Ma. Accordingly, the LDI does not match other paleotemperature proxies, suggesting its applicability might be compromised for sediments older than the Miocene. Our results indicate that of the three proxies, the TEX86 seems to be the most applicable for deep time temperature reconstructions.

On the origin of obesity: identifying the biological, environmental and cultural drivers of genetic risk among human populations.

Genetic predisposition to obesity presents a paradox: how do genetic variants with a detrimental impact on human health persist through evolutionary time? Numerous hypotheses, such as the thrifty genotype hypothesis, attempt to explain this phenomenon yet fail to provide a justification for the modern obesity epidemic. In this critical review, we appraise existing theories explaining the evolutionary origins of obesity and explore novel biological and sociocultural agents of evolutionary change to help explain the modern-day distribution of obesity-predisposing variants. Genetic drift, acting as a form of 'blind justice,' may randomly affect allele frequencies across generations while gene pleiotropy and adaptations to diverse environments may explain the rise and subsequent selection of obesity risk alleles. As an adaptive response, epigenetic regulation of gene expression may impact the manifestation of genetic predisposition to obesity. Finally, exposure to malnutrition and disease epidemics in the wake of oppressive social systems, culturally mediated notions of attractiveness and desirability, and diverse mating systems may play a role in shaping the human genome. As an important first step towards the identification of important drivers of obesity gene evolution, this review may inform empirical research focused on testing evolutionary theories by way of population genetics and mathematical modelling.

Around the World in Eight Million Years: Historical Biogeography and Evolution of the Spray Zone Spider Amaurobioides (Araneae: Anyphaenidae).

Closely related organisms with transoceanic distributions have long been the focus of historical biogeography, prompting the question of whether long-distance dispersal, or tectonic-driven vicariance shaped their current distribution. Regarding the Southern Hemisphere continents, this question deals with the break-up of the Gondwanan landmass, which has also affected global wind and oceanic current patterns since the Miocene. With the advent of phylogenetic node age estimation and parametric bioinformatic advances, researchers have been able to disentangle historical evolutionary processes of taxa with greater accuracy. In this study, we used the coastal spider genus Amaurobioides to investigate the historical biogeographical and evolutionary processes that shaped the modern-day distribution of species of this exceptional genus of spiders. As the only genus of the subfamily Amaurobioidinae found on three Southern Hemisphere continents, its distribution is well-suited to study in the context of Gondwanic vicariance versus long-distance, transoceanic dispersal. Ancestral species of the genus Amaurobioides appear to have undergone several long-distance dispersal events followed by successful establishments and speciation, starting from the mid-Miocene through to the Pleistocene. The most recent common ancestor of all present-day Amaurobioides species is estimated to have originated in Africa after arriving from South America during the Miocene. From Africa the subsequent dispersals are likely to have taken place predominantly in an eastward direction. The long-distance dispersal events by Amaurobioides mostly involved transoceanic crossings, which we propose occurred by rafting, aided by the Antarctic Circumpolar Current and the West Wind Drift.

Mitochondrial DNA from the eradicated European Plasmodium vivax and P. falciparum from 70-year-old slides from the Ebro Delta in Spain

Phylogenetic analysis of Plasmodium parasites has indicated that their modern-day distribution is a result of a series of human-mediated dispersals involving transport between Africa, Europe, America, and Asia. A major outstanding question is the phylogenetic affinity of the malaria causing parasites Plasmodium vivax and falciparum in historic southern Europe-where it was endemic until the mid-20th century, after which it was eradicated across the region. Resolving the identity of these parasites will be critical for answering several hypotheses on the malaria dispersal. Recently, a set of slides with blood stains of malaria-affected people from the Ebro Delta (Spain), dated between 1942 and 1944, have been found in a local medical collection. We extracted DNA from three slides, two of them stained with Giemsa (on which Plasmodium parasites could still be seen under the microscope) and another one consisting of dried blood spots. We generated the data using Illumina sequencing after using several strategies aimed at increasing the Plasmodium DNA yield: depletion of the human genomic (g)DNA content through hybridization with human gDNA baits, and capture-enrichment using gDNA derived from P. falciparum Plasmodium mitochondrial genome sequences were subsequently reconstructed from the resulting data. Phylogenetic analysis of the eradicated European P. vivax mtDNA genome indicates that the European isolate is closely related to the most common present-day American haplotype and likely entered the American continent post-Columbian contact. Furthermore, the European P. falciparum mtDNA indicates a link with current Indian strains that is in agreement with historical accounts.

Ancient DNA reveals complexity in the evolutionary history and taxonomy of the endangered Australian brush-tailed bettongs (Bettongia: Marsupialia: Macropodidae: Potoroinae)

The three surviving ‘brush-tailed’ bettong species—Bettongia gaimardi (Tasmania), B. tropica (Queensland) and B. penicillata (Western Australia), are all classified as threatened or endangered. These macropodids are prolific diggers and are recognised as important ‘ecosystem engineers’ that improve soil quality and increase seed germination success. However, a combination of introduced predators, habitat loss and disease has seen populations become increasingly fragmented and census numbers decline. Robust phylogenies are vital to conservation management, but the extent of extirpation and fragmentation in brush-tailed bettongs is such that a phylogeny based upon modern samples alone may provide a misleading picture of former connectivity, genetic diversity and species boundaries. Using ancient DNA isolated from fossil bones and museum skins, we genotyped two mitochondrial DNA (mtDNA) genes: cytochrome b (266 bp) and control region (356 bp). These ancient DNA data were combined with a pre-existing modern DNA data set on the historically broadly distributed brush-tailed bettongs (~300 samples total), to investigate their phylogenetic relationships. Molecular dating estimates the most recent common ancestor of these bettongs occurred c. 2.5 Ma (million years ago), which suggests that increasing aridity likely shaped their modern-day distribution. Analyses of the concatenated mtDNA sequences of all brush-tailed bettongs generated five distinct and well-supported clades including: a highly divergent Nullarbor form (Clade I), B. tropica (Clade II), B. penicillata (Clades III and V), and B. gaimardi (Clade IV). The generated phylogeny does not reflect current taxonomy and the question remains outstanding of whether the brush-tailed bettongs consisted of several species, or a single widespread species. The use of nuclear DNA markers (single nucleotide polymorphisms and/or short tandem repeats) will be needed to better inform decisions about historical connectivity and the appropriateness of ongoing conservation measures such as translocations and captive breeding.

Interpreting the modern distribution of Myrtaceae using a dated molecular phylogeny

The angiosperm family Myrtaceae has extant and fossil taxa from all southern continents and is assumed to be of Gondwanan origin. Many modern groups contain sister taxa that have disjunct transoceanic distributions, which can be interpreted as a result of either vicariance or long-distance dispersal and establishment (LDDE). Further, some Myrtaceae groups occur on Pacific islands with enigmatic geological histories. We tested hypotheses of vicariance and LDDE by estimating divergence times using a relaxed molecular clock calibrated with 12 fossils. In total, 88 genera and 202 species were sampled, representing both subfamilies and all tribes of Myrtaceae. We reconstructed the family as Gondwanan in origin. Of the 22 geographically disjunct sister groups in our study, up to six are potentially explained as the product of vicariance, three resulting from overland dispersal via new land connections, and 13 due to LDDE events. Nine of the 13 hypothesized LDDE events occurred in fleshy-fruited taxa. Our results indicate that most of the transoceanic distribution patterns in Myrtaceae have occurred since the Miocene due to LDDE, whereas inferred vicariance events all occurred before the Late Eocene. There are many instances of sister relationships between species-poor and species-rich groups in Myrtaceae, and at least three occurrences of geographically isolated taxa on long branches of the phylogeny (Arillastrum, Myrtus, and Tepualia), whose modern-day distributions are difficult to explain without additional fossil or geological evidence.

The Fourteenth-Century Poll Tax Returns and the Study of English Surname Distribution

. The modern-day distributions of English surnames have been considered in genealogical, historical, and philological research as possible indicators of their origins. However, many centuries have passed since hereditary surnames were first used, and so their distribution today does not necessarily reflect their original spread, misrepresenting their origins. Previously, medieval data with national coverage have not been available for a study of surname distribution, but with the recent publication of the fourteenth-century poll tax returns, this has changed. By presenting discrepancies in medieval and nineteenth-century distributions, it is shown that more recent surname data may not be a suitable guide to surname origins and can be usefully supplemented by medieval data in order to arrive at more accurate conclusions.

Reconstructing Plate Tectonics

Geophysics The modern-day distribution of Earth's tectonic plates is just a snapshot of an ever-changing process. Reconstructions of previous plate arrangements have resulted in the identification of the ancient supercontinents Pangea and Rodinia, but does this cycle follow any sort of predictable law o r pattern? Morra et al. statistically analyzed the organization of large and small plates across Earth's surface over the past 200 million years, based on models of plate reconstructions. Small plates do not show much statistical variation in their distribution over time, because they are largely unstable and form from unrelated events. Large plates, however, tend to organize either into heterogeneous or homogenous states based on plate size distributions over ∼100-million-year time scales. The rapid rate at which heterogeneous distribution states are stabilized suggests that these may be excited states, whereas homogeneous distribution states tend more toward equilibrium. In this case, the underlying driving force for the transition from one state to another depends on cycling between top-down and bottom-up mantle convection as a control on plate motion. Earth Planet. Sci. Lett. 373 , 93 (2013).

Last interglacial beetle fauna from New Zealand

Fossil beetles from two last interglacial lake deposits from southern Wairarapa, central New Zealand are provisionally ascribed to marine oxygen isotope stages (MIS) 5a–e. Both assemblages represent ecological successions from lake margins to forest. The lower sample (MIS 5e) is characterized by species found today in northern New Zealand. These species, including Lorelus crassicornis, ‘Dasytes’ laticeps, Cryptobius nitidius, ‘Stenomalium’ sulcithorax, Psilocnaeia nana, and Microbrontes lineatus, represent a southward displacement from modern distributions by up to 700 km. Climate reconstruction indicates that temperatures at the time of deposition were 1.6–2.5°C warmer in the summer (January) and 2.3–3.2°C warmer in the winter (July) than at present. These results match local and regional pollen and phytolith findings of warmer, wetter conditions at the thermal maximum of the last interglaciation. In contrast, the upper sample is characterized by species that have widespread modern-day distributions. This indicates that modern conditions were attained later in MIS5, after the MIS 5e thermal maximum.

Surficial sediments of the outer banks, Scotian Shelf, Canada

The distribution, thickness, and mean grain size of surficial sediments on Sable Island Bank, Middle Bank, and Banquereau, Scotian Shelf, are used to re-evaluate interpretations made by others on mechanisms controlling long-term stability and net transport pathways of surface sand. A Holocene sand-ridge complex, the Sable Island Catena, extends 300 km across Sable Island Bank and Banquereau. This sand-ridge complex, which is up to 50 m thick, formed as a result of Holocene sediment transport on the outer banks and controls the modern-day distribution of bedforms and sediment size. A clockwise circulation of sand centred around Sable Island, which had been proposed as the mechanism maintaining the island, does not take place. Sand is transported from southwest to northeast across Sable Island Bank towards the Sable Island Catena; thereafter, sand is dispersed eastward. "Spillover" of sand from the banks to The Gully is not significant. Sand is trapped in depths less than 100 m. The processes proposed to have formed the Sable Island Catena are barotropic, storm-driven currents and associated sand transport and "fair-weather" dispersion of sand by strong, tidal flows or baroclinic currents, coupled with an abundant supply of sand-size sediment.