Browsing by Subject "ORIGIN"

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  • Duggan, Ana T.; Perdomo, Maria F.; Piombino-Mascali, Dario; Marciniak, Stephanie; Poinar, Debi; Emery, Matthew V.; Buchmann, Jan P.; Duchene, Sebastian; Jankauskas, Rimantas; Humphreys, Margaret; Golding, G. Brian; Southon, John; Devault, Alison; Rouillard, Jean-Marie; Sahl, Jason W.; Dutour, Olivier; Hedman, Klaus; Sajantila, Antti; Smith, Geoffrey L.; Holmes, Edward C.; Poinar, Hendrik N. (2016)
    Smallpox holds a unique position in the history of medicine. It was the first disease for which a vaccine was developed and remains the only human disease eradicated by vaccination. Although there have been claims of smallpox in Egypt, India, and China dating back millennia [1-4], the timescale of emergence of the causative agent, variola virus (VARV), and how it evolved in the context of increasingly widespread immunization, have proven controversial [4-9]. In particular, some molecular-clock-based studies have suggested that key events in VARV evolution only occurred during the last two centuries [4-6] and hence in apparent conflict with anecdotal historical reports, although it is difficult to distinguish smallpox from other pustular rashes by description alone. To address these issues, we captured, sequenced, and reconstructed a draft genome of an ancient strain of VARV, sampled from a Lithuanian child mummy dating between 1643 and 1665 and close to the time of several documented European epidemics [1, 2, 10]. When compared to vaccinia virus, this archival strain contained the same pattern of gene degradation as 20th century VARVs, indicating that such loss of gene function had occurred before ca. 1650. Strikingly, the mummy sequence fell basal to all currently sequenced strains of VARV on phylogenetic trees. Molecular-clock analyses revealed a strong clock-like structure and that the timescale of smallpox evolution is more recent than often supposed, with the diversification of major viral lineages only occurring within the 18th and 19th centuries, concomitant with the development of modern vaccination.
  • Ala-Lahti, Matti; Kilpua, Emilia K. J.; Soucek, Jan; Pulkkinen, Tuija; Dimmock, Andrew P. (2019)
    We report on a statistical analysis of the occurrence and properties of Alfven ion cyclotron (AIC) waves in sheath regions driven by interplanetary coronal mass ejections (ICMEs). We have developed an automated algorithm to identify AIC wave events from magnetic field data and apply it to investigate 91 ICME sheath regions recorded by the Wind spacecraft. Our analysis focuses on waves generated by the ion cyclotron instability. AIC waves are observed to be frequent structures in ICME-driven sheaths, and their occurrence is the highest in the vicinity of the shock. Together with previous studies, our results imply that the shock compression has a crucial role in generating wave activity in ICME sheaths. AIC waves tend to have their frequency below the ion cyclotron frequency, and, in general, occur in plasma that is stable with respect to the ion cyclotron instability and has lower ion beta(parallel to) than mirror modes. The results suggest that the ion beta anisotropy beta(perpendicular to)/beta(parallel to) > 1 appearing in ICME sheaths is regulated by both ion cyclotron and mirror instabilities.
  • Kerr, Shona M.; Klaric, Lucija; Halachev, Mihail; Hayward, Caroline; Boutin, Thibaud S.; Meynert, Alison M.; Semple, Colin A.; Tuiskula, Annukka M.; Swan, Heikki; Santoyo-Lopez, Javier; Vitart, Veronique; Haley, Chris; Dean, John; Miedzybrodzka, Zosia; Aitman, Timothy J.; Wilson, James F. (2019)
    The Viking Health Study Shetland is a population-based research cohort of 2,122 volunteer participants with ancestry from the Shetland Isles in northern Scotland. The high kinship and detailed phenotype data support a range of approaches for associating rare genetic variants, enriched in this isolate population, with quantitative traits and diseases. As an exemplar, the c.1750G > A; p.Gly584Ser variant within the coding sequence of the KCNH2 gene implicated in Long QT Syndrome (LQTS), which occurred once in 500 whole genome sequences from this population, was investigated. Targeted sequencing of the KCNH2 gene in family members of the initial participant confirmed the presence of the sequence variant and identified two further members of the same family pedigree who shared the variant. Investigation of these three related participants for whom single nucleotide polymorphism (SNP) array genotypes were available allowed a unique shared haplotype of 1.22 Mb to be defined around this locus. Searching across the full cohort for this haplotype uncovered two additional apparently unrelated individuals with no known genealogical connection to the original kindred. All five participants with the defined haplotype were shown to share the rare variant by targeted Sanger sequencing. If this result were verified in a healthcare setting, it would be considered clinically actionable, and has been actioned in relatives ascertained independently through clinical presentation. The General Practitioners of four study participants with the rare variant were alerted to the research findings by letters outlining the phenotype (prolonged electrocardiographic QTc interval). A lack of detectable haplotype sharing between c.1750G > A; p.Gly584Ser chromosomes from previously reported individuals from Finland and those in this study from Shetland suggests that this mutation has arisen more than once in human history. This study showcases the potential value of isolate population-based research resources for genomic medicine. It also illustrates some challenges around communication of actionable findings in research participants in this context.
  • Majander, Kerttu; Pfrengle, Saskia; Kocher, Arthur; Neukamm, Judith; du Plessis, Louis; Pla-Diaz, Marta; Arora, Natasha; Akgul, Gulfirde; Salo, Kati; Schats, Rachel; Inskip, Sarah; Oinonen, Markku; Valk, Heiki; Malve, Martin; Kriiska, Aivar; Onkamo, Paivi; Gonzalez-Candelas, Fernando; Kuehnert, Denise; Krause, Johannes; Schuenemann, Verena J. (2020)
    Syphilis is a globally re-emerging disease, which has marked European history with a devastating epidemic at the end of the 15th century. Together with non-venereal treponemal diseases, like bejel and yaws, which are found today in subtropical and tropical regions, it currently poses a substantial health threat worldwide. The origins and spread of treponemal diseases remain unresolved, including syphilis' potential introduction into Europe from the Americas. Here, we present the first genetic data from archaeological human remains reflecting a high diversity of Treponema pallidumin early modern Europe. Our study demonstrates that a variety of strains related to both venereal syphilis and yaws-causing T. pallidum subspecies were already present in Northern Europe in the early modern period. We also discovered a previously unknown T. pallidum lineage recovered as a sister group to yaws- and bejel-causing lineages. These findings imply a more complex pattern of geographical distribution and etiology of early treponemal epidemics than previously understood.
  • Arju, Georg; Taivosalo, Anastassia; Pismennoi, Dmitri; Lints, Taivo; Vilu, Raivo; Daneberga, Zanda; Vorslova, Svetlana; Renkonen, Risto; Joenvaara, Sakari (2020)
    Until now, cheese peptidomics approaches have been criticised for their lower throughput. Namely, analytical gradients that are most commonly used for mass spectrometric detection are usually over 60 or even 120 min. We developed a cheese peptide mapping method using nano ultra-high-performance chromatography data-independent acquisition high-resolution mass spectrometry (nanoUHPLC-DIA-HRMS) with a chromatographic gradient of 40 min. The 40 min gradient did not show any sign of compromise in milk protein coverage compared to 60 and 120 min methods, providing the next step towards achieving higher-throughput analysis. Top 150 most abundant peptides passing selection criteria across all samples were cross-referenced with work from other publications and a good correlation between the results was found. To achieve even faster sample turnaround enhanced DIA methods should be considered for future peptidomics applications.
  • Lutfullahoglu-Bal, Guleycan; Keskin, Abdurrahman; Seferoglu, Ayse Bengisu; Dunn, Cory D. (2017)
    Background: During the generation and evolution of the eukaryotic cell, a proteobacterial endosymbiont was re-fashioned into the mitochondrion, an organelle that appears to have been present in the ancestor of all present-day eukaryotes. Mitochondria harbor proteomes derived from coding information located both inside and outside the organelle, and the rate-limiting step toward the formation of eukaryotic cells may have been development of an import apparatus allowing protein entry to mitochondria. Currently, a widely conserved translocon allows proteins to pass from the cytosol into mitochondria, but how proteins encoded outside of mitochondria were first directed to these organelles at the dawn of eukaryogenesis is not clear. Because several proteins targeted by a carboxyl-terminal tail anchor (TA) appear to have the ability to insert spontaneously into the mitochondrial outer membrane (OM), it is possible that self-inserting, tail-anchored polypeptides obtained from bacteria might have formed the first gate allowing proteins to access mitochondria from the cytosol. Results: Here, we tested whether bacterial TAs are capable of targeting to mitochondria. In a survey of proteins encoded by the proteobacterium Escherichia coli, predicted TA sequences were directed to specific subcellular locations within the yeast Saccharomyces cerevisiae. Importantly, TAs obtained from DUF883 family members ElaB and YqjD were abundantly localized to and inserted at the mitochondrial OM. Conclusions: Our results support the notion that eukaryotic cells are able to utilize membrane-targeting signals present in bacterial proteins obtained by lateral gene transfer, and our findings make plausible a model in which mitochondrial protein translocation was first driven by tail-anchored proteins.
  • Riihimaki, Matias; Hemminki, Akseli; Sundquist, Kristina; Hemminki, Kari (2014)
  • Stanczuk, Lukas; Martinez-Corral, Ines; Ulvmar, Maria H.; Zhang, Yang; Lavina, Barbbara; Fruttiger, Marcus; Adams, Ralf H.; Saur, Dieter; Betsholtz, Christer; Ortega, Sagrario; Alitalo, Kari; Graupera, Mariona; Makinen, Taija (2015)
  • Good, S. W.; Kilpua, E. K. J.; Ala-Lahti, M.; Osmane, A.; Bale, S. D.; Zhao, L. -L. (2020)
    Magnetic clouds are large-scale transient structures in the solar wind with low plasma-beta, low-amplitude magnetic field fluctuations, and twisted field lines with both ends often connected to the Sun. Their inertial-range turbulent properties have not been examined in detail. In this Letter, we analyze the normalized cross helicity, sigma(c), and residual energy, sigma(r), of plasma fluctuations in the 2018 November magnetic cloud observed at by the Parker Solar Probe. A low value of |sigma(c)| was present in the cloud core, indicating that wave power parallel and antiparallel to the mean field was approximately balanced, while the cloud's outer layers displayed larger amplitude Alfvenic fluctuations with high |sigma(c)| values and sigma(r) similar to 0. These properties are discussed in terms of the cloud's solar connectivity and local interaction with the solar wind. We suggest that low |sigma(c)| is likely a common feature of magnetic clouds given their typically closed field structure. Antisunward fluctuations propagating immediately upstream of the cloud had strongly negative sigma(r) values.
  • Kieseppä, Valentina; Holm, Minna; Jokela, Markus; Suvisaari, Jaana; Gissler, Mika; Lehti, Venla (2021)
    Background: The aims of this study were to (1) compare differences in psychiatric comorbidity of depression and anxiety disorders between immigrants and native Finns and to (2) compare differences in the intensity of psychiatric care received by different immigrant groups and Finnish-born controls with depression and/or anxiety disorders. Methods: The study uses registered-based data, which includes all immigrants living in Finland at the end of 2010 and matched Finnish-born controls. For this study, we selected individuals who had received a diagnosis of depression and/or an anxiety disorder during the follow-up (2011?2015) (immigrants n = 6542, Finnish-born controls n = 9281). We compared differences in comorbidity between the immigrants and the Finnish-born controls using chi-squared tests. Multinomial logistic regression was used to predict psychiatric treatment intensity by immigrant status, region of origin, and other background factors. Results: In both diagnosis groups, Finnish-born participants exhibited greater comorbidity of other psychiatric disorders. Immigrants more often received lower intensity treatment and less often higher intensity treatment. These differences were most striking among those from Eastern Europe, the Middle East, and Africa. Limitations: We did not have the information on the perceived need for the services, which limits us from drawing further conclusions about the mechanisms behind the observed patterns. Conclusions: Immigrants in Finland receive less intensive treatment for depression and anxiety disorders compared to the Finnish-born population. Since lower symptom levels can unlikely alone explain these differences, they could reflect a need for improvement in the psychiatric services for immigrants.
  • Cascone, Annunziata; Bruelle, Celine; Lindholm, Dan; Bernardi, Paolo; Eriksson-Rosenberg, Ove (2012)
  • Nikbakhsh, S.; Tanskanen, E. I.; Käpylä, M. J.; Hackman, T. (2019)
    Aims. Our aim is to examine the solar cycle variability of magnetically simple and complex active region. Methods. We studied simple (alpha and beta) and complex (beta gamma and beta gamma delta) active regions based on the Mount Wilson magnetic classification by applying our newly developed daily approach. We analyzed the daily number of the simple active regions (SARs) and compared that to the abundance of the complex active regions (CARs) over the entire solar cycle 23 and cycle 24 until December 2018. Results. We show that CARs evolve differently over the solar cycle from SARs. The time evolution of SARs and CARs on different hemispheres also shows differences, even though on average their latitudinal distributions are shown to be similar. The time evolution of SARs closely follows that of the sunspot number, and their maximum abundance was observed to occur during the early maximum phase, while that of the CARs was seen roughly two years later. We furthermore found that the peak of CARs was reached before the latitudinal width of the activity band starts to decease. Conclusion. Our results suggest that the active region formation process is a competition between the large-scale dynamo (LSD) and the small-scale dynamo (SSD) near the surface, the former varying cyclically and the latter being independent of the solar cycle. During solar maximum, LSD is dominant, giving a preference to SARs, while during the declining phase the relative role of SSD increases. Therefore, a preference for CARs is seen due to the influence of the SSD on the emerging flux.
  • MacLennan, Eric; Toliou, Athanasia; Granvik, Mikael (2021)
    The near-Earth objects (NEOs) (3200) Phaethon and (155140) 2005 UD are thought to share a common origin, with the former exhibiting dust activity at perihelion that is thought to directly supply the Geminid meteor stream. Both of these objects currently have very small perihelion distances (0.140 au and 0.163 au for Phaethon and 2005 UD, respectively), which results in them having perihelion temperatures around 1000 K. A comparison between NEO population models to discovery statistics suggests that low-perihelion objects are destroyed over time by a, possibly temperature-dependent, mechanism that is efficient at heliocentric distances less than 0.3 au. By implication, the current activity from Phaethon is linked to the destruction mechanism of NEOs close to the Sun. We model the past thermal characteristics of Phaethon and 2005 UD using a combination of a thermophysical model (TPM) and orbital integrations of each object. Temperature characteristics such as maximum daily temperature, maximum thermal gradient, and temperature at different depths are extracted from the model, which is run for a predefined set of semi-major axis and eccentricity values. Next, dynamical integrations of orbital clones of Phaethon and 2005 UD are used to estimate the past orbital elements of each object. These dynamical results are then combined with the temperature characteristics to model the past evolution of thermal characteristics such as maximum (and minimum) surface temperature and thermal gradient. The orbital histories of Phaethon and 2005 UD are characterized by cyclic changes in.., resulting in perihelia values periodically shifting between present-day values and 0.3 au. Currently, Phaethon is experiencing relatively large degrees of heating when compared to the recent 20, 000 yr. We find that the subsurface temperatures are too large over this timescale for water ice to be stable, unless actively supplied somehow. The near-surface thermal gradients strongly suggest that thermal fracturing may be very effective at breaking down and ejecting dust particles. Observations by the DESTINY+ flyby mission will provide important constraints on the mechanics of dust-loss from Phaethon and, potentially, reveal signs of activity from 2005 UD. In addition to simulating the recent dynamical evolution of these objects, we use orbital integrations that start from the Main Belt to assess their early dynamical evolution (origin and delivery mechanism). We find that dwarf planet (2) Pallas is unlikely to be the parent body for Phaethon and 2005 UD, and it is more likely that the source is in the inner part of the asteroid belt in the families of, e.g., (329) Svea or (142) Polana.
  • Joensuu, Heikki; Wardelmann, Eva; Sihto, Harri; Eriksson, Mikael; Hall, Kirsten Sundby; Reichardt, Annette; Hartmann, Joerg T.; Pink, Daniel; Cameron, Silke; Hohenberger, Peter; Al-Batran, Salah-Eddin; Schlemmer, Marcus; Bauer, Sebastian; Nilsson, Bengt; Kallio, Raija; Junnila, Jouni; Vehtari, Aki; Reichardt, Peter (2017)
    IMPORTANCE Little is known about whether the duration of adjuvant imatinib influences the prognostic significance of KIT proto-oncogene receptor tyrosine kinase (KIT) and platelet-derived growth factor receptor a (PDGFRA) mutations. OBJECTIVE To investigate the effect of KIT and PDGFRA mutations on recurrence-free survival (RFS) in patients with gastrointestinal stromal tumors (GISTs) treated with surgery and adjuvant imatinib. DESIGN, SETTING, AND PARTICIPANTS This exploratory study is based on the Scandinavian Sarcoma Group VIII/Arbeitsgemeinschaft Internistische Onkologie (SSGXVIII/AIO) multicenter clinical trial. Between February 4, 2004, and September 29, 2008, 400 patients who had undergone surgery for GISTs with a high risk of recurrence were randomized to receive adjuvant imatinib for 1 or 3 years. Of the 397 patients who provided consent, 341 (85.9%) had centrally confirmed, localized GISTs with mutation analysis for KIT and PDGFRA performed centrally using conventional sequencing. During a median follow-up of 88 months (completed December 31, 2013), 142 patients had GIST recurrence. Data of the evaluable population were analyzed February 4, 2004, through December 31, 2013. MAIN OUTCOMES AND MEASURES The main outcome was RFS. Mutations were grouped by the gene and exon. KIT exon 11 mutations were further grouped as deletion or insertion-deletion mutations, substitution mutations, insertion or duplication mutations, and mutations that involved codons 557 and/or 558. RESULTS Of the 341 patients (175 men and 166women; median age at study entry, 62 years) in the 1-year group and 60 years in the 3-year group), 274 (80.4%) had GISTs with a KIT mutation, 43 (12.6%) had GISTs that harbored a PDGFRA mutation, and 24 (7.0%) had GISTs thatwere wild type for these genes. PDGFRA mutations and KIT exon 11 insertion or duplication mutations were associated with favorable RFS, whereas KIT exon 9 mutations were associated with unfavorable outcome. Patients with KIT exon 11 deletion or insertion-deletion mutation had better RFS when allocated to the 3-year group compared with the 1-year group (5-year RFS, 71.0% vs 41.3%; P CONCLUSIONS AND RELEVANCE Patients with KIT exon 11 deletion mutations benefit most from the longer duration of adjuvant imatinib. The duration of adjuvant imatinib modifies the risk of GIST recurrence associated with some KIT mutations, including deletions that affect exon 11 codons 557 and/or 558.
  • Nokireki, Tiina; Jakava-Viljanen, Miia; Virtala, Anna-Maija; Sihvonen, Liisa (2017)
    Background: Rabies is preventable by pre-and/or post-exposure prophylaxis consisting of series of rabies vaccinations and in some cases the use of immunoglobulins. The success of vaccination can be estimated either by measuring virus neutralising antibodies or by challenge experiment. Vaccines based on rabies virus offer cross-protection against other lyssaviruses closely related to rabies virus. The aim was to assess the success of rabies vaccination measured by the antibody response in dogs (n = 10,071) and cats (n = 722), as well as to investigate the factors influencing the response to vaccination when animals failed to reach a rabies antibody titre of = 0.5 IU/ml. Another aim was to assess the level of protection afforded by a commercial veterinary rabies vaccine against intracerebral challenge in mice with European bat lyssavirus type 2 (EBLV-2) and classical rabies virus (RABV), and to compare this with the protection offered by a vaccine for humans. Results: A significantly higher proportion of dogs (10.7%, 95% confidence interval CI 10.1-11.3) than cats (3.5%; 95% CI 2.3-5.0) had a vaccination antibody titre of <0.5 IU/ml. In dogs, vaccination with certain vaccines, vaccination over 6 months prior the time of antibody determination and vaccination of dogs with a size of > 60 cm or larger resulted in a higher risk of failing to reach an antibody level of at least 0.5 IU/ml. When challenged with EBLV-2 and RABV, 80 and 100% of mice vaccinated with the veterinary rabies vaccine survived, respectively. When mice were vaccinated with the human rabies vaccine and challenged with EBLV-2, 75-80% survived, depending on the booster. All vaccinated mice developed sufficient to high titres of virus-neutralising antibodies (VNA) against RABV 21-22 days post-vaccination, ranging from 0.5 to 128 IU/ml. However, there was significant difference between antibody titres after vaccinating once in comparison to vaccinating twice (P <0.05). Conclusions: There was a significant difference between dogs and cats in their ability to reach a post vaccination antibody titre of = 0.5 IU/ml. Mice vaccinated with RABV-based rabies vaccines were partly cross-protected against EBLV-2, but there was no clear correlation between VNA titres and cross-protection against EBLV-2. Measurement of the RABV VNA titre can only be seen as a partial tool to estimate the cross-protection against other lyssaviruses. Booster vaccination is recommended for dogs and cats if exposed to infected bats.
  • Prasad, Rashmi B.; Lessmark, Anna; Almgren, Peter; Kovacs, Gyorgyi; Hansson, Ola; Oskolkov, Nikolay; Vitai, Marta; Ladenvall, Claes; Kovacs, Peter; Fadista, Joao; Lachmann, Michael; Zhou, Yuedan; Sonestedt, Emily; Poon, Wenny; Wollheim, Claes B.; Orho-Melander, Marju; Stumvoll, Michael; Tuomi, Tiinamaija; Paeaebo, Svante; Koranyi, Laszlo; Groop, Leif (2016)
    Aims/hypothesis Genome-wide association studies (GWAS) have identified more than 65 genetic loci associated with risk of type 2 diabetes. However, the contribution of distorted parental transmission of alleles to risk of type 2 diabetes has been mostly unexplored. Our goal was therefore to search for parent-of-origin effects (POE) among type 2 diabetes loci in families. Methods Families from the Botnia study (n = 4,211, 1,083 families) were genotyped for 72 single-nucleotide polymorphisms (SNPs) associated with type 2 diabetes and assessed for POE on type 2 diabetes. The family-based Hungarian Transdanubian Biobank (HTB) (n = 1,463, > 135 families) was used to replicate SNPs showing POE. Association of type 2 diabetes loci within families was also tested. Results Three loci showed nominal POE, including the previously reported variants in KCNQ1, for type 2 diabetes in families from Botnia (rs2237895: p(POE) = 0.037), which can be considered positive controls. The strongest POE was seen for rs7578597 SNP in the THADA gene, showing excess transmission of the maternal risk allele T to diabetic offspring (Botnia: p(POE) = 0.01; HTB p(POE) = 0.045). These data are consistent with previous evidence of allelic imbalance for expression in islets, suggesting that the THADA gene can be imprinted in a POE-specific fashion. Five CpG sites, including those flanking rs7578597, showed differential methylation between diabetic and non-diabetic donor islets. Conclusions/interpretation Taken together, the data emphasise the need for genetic studies to consider from which parent an offspring has inherited a susceptibility allele.
  • Porokuokka, L. Lauriina; Virtanen, Heikki T.; Linden, Jere; Sidorova, Yulia; Danilova, Tatiana; Lindahl, Maria; Saarma, Mart; Andressoo, Jaan-Olle (2019)
    BACKGROUND & AIMS: RET, the receptor for the glial cell line-derived neurotrophic factor (GDNF) family ligands, is the most frequently mutated gene in congenital aganglionic megacolon or Hirschsprung's disease (HSCR). The leading cause of mortality in HSCR is HSCR-associated enterocolitis (HAEC), which is characterized by altered mucin composition, mucin retention, bacterial adhesion to enterocytes, and epithelial damage, although the order of these events is obscure. In mice, loss of GDNF signaling leads to a severely underdeveloped enteric nervous system and neonatally fatal kidney agenesis, thereby precluding the use of these mice for modeling postnatal HSCR and HAEC. Our aim was to generate a postnatally viable mouse model for HSCR/HAEC and analyze HAEC etiology. METHODS: GDNF family receptor alpha-1 (GFRa1) hypomorphic mice were generated by placing a selectable marker gene in the sixth intron of the Gfra1 locus using gene targeting in mouse embryonic stem cells. RESULTS: We report that 70%-80% reduction in GDNF co-receptor GFRa1 expression levels in mice results in HSCR and HAEC, leading to death within the first 25 postnatal days. These mice mirror the disease progression and histopathologic findings in children with untreated HSCR/HAEC. CONCLUSIONS: In GFRa1 hypomorphic mice, HAEC proceeds from goblet cell dysplasia, with abnormal mucin production and retention, to epithelial damage. Microbial enterocyte adherence and tissue invasion are late events and therefore unlikely to be the primary cause of HAEC. These results suggest that goblet cells may be a potential target for preventative treatment and that reduced expression of GFRa1 may contribute to HSCR susceptibility.
  • Heinonen, Aku; Kivisaari, Heli; Michallik, Radoslaw (2020)
    The occurrence of high-aluminum orthopyroxene megacrysts (HAOMs) in several massif-type Proterozoic anorthosite complexes has been used as evidence of their polybaric crystallization. Here, we report such petrographic and geochemical (XRF and EMPA) evidence from HAOMs discovered in the 1.64 Ga Ahvenisto rapakivi granite-massif-type anorthosite complex in southeastern Finland. Two different types of HAOMs were recognized: type 1 HAOMs are individual, euhedral-to-subhedral crystals, and up to 15 cm in diameter, and type 2 HAOMs occur in pegmatitic pockets closely associated with megacrystic (up to 30 cm long) plagioclase. The type 1 megacrysts in particular are surrounded by complex corona structures composed of plagioclase, low-Al orthopyroxene, iddingsite (after olivine), and sulfides. Orthopyroxene crystallization pressure estimates based on an Al-in-Opx geobarometer reveal a three-stage compositional evolution in both textural HAOM types. The Al content decreases significantly from the core regions of the HAOM (4.4-7.6 wt% Al2O3), through the rims (1.3-3.6 wt%), into the host rock (0.5-1.5 wt%). Enstatite compositions overlap, but are generally higher in the cores (En(similar to 60-70)) and rims (En(similar to 50-70)) of the HAOMs than in the host rock (En(similar to 45-60)) orthopyroxenes. The highest recorded Al abundances in the HAOM cores correspond to crystallization pressures of up to similar to 1.1 GPa (similar to 34 km depth), whereas the HAOM rims have crystallized at lower pressures (max. similar to 0.5 GPa, 20 km depth). The highest pressure estimates for the host rock orthopyroxene were similar to 0.2 GPa (<7 km depth). These observations confirm the polybaric magmatic evolution of the Ahvenisto anorthosites and suggest that the entire 1.65-1.55 Ga Fennoscandian rapakivi suite was emplaced at a relatively shallow level (<7 km depth) in the upper crust. Global comparison to similar rock types reveals remarkable similarities in the petrogenetic processes controlling HAOM composition and evolution of anorthosite parental magmas.
  • Poczai, Péter; Santiago-Blay, Jorge; Sekerák, Jiří; T. Szabó, Attila (2021)
    The nineteenth century was a time of great economic, social, and political change. The population of a modernizing Europe began demanding more freedom, which in turn propelled the ongoing discussion on the philosophy of nature. This spurred on Central European sheep breeders to debate the deepest secrets of nature: the transmission of traits from one generation to another. Scholarly questions of heredity were profoundly entwined with philosophy and politics when particular awareness of "the genetic laws of nature" claimed natural equality. The realization that the same rules of inheritance may apply to all living beings frightened both the absolutist political power and the divided society of the day. Many were not prepared to separate religious questions from novel natural phenomena. Open-minded breeders put their knowledge into practice right away to create sheep with better wool traits through inbreeding and artificial selection. This was viewed, however, as the artificial modification of nature operating against the cultural and religious norms of the day. Liberal attempts caught the attention of the secret police and, consequently, the aspirations of scholars were suppressed by political will during approximately 1820-1850.