16 research outputs found
The `Second Parameter': A Memory from the Globular Cluster Formation Epoch
We study the correlations between the distribution of stars on the horizontal
branch (HB), the HB morphology, with some other properties of globular clusters
(GCs) in a large sample of GCs. We strengthen previous results that a general
correlation exists only between HB morphology and metallicity. Correlations
with other properties, e.g., central density and core radius, exist only for
GCs within a narrow metallicity range. We conjecture that the lack of
correlations with present properties of GCs (besides metallicity), is because
the variation of the HB morphologies between GCs having similar metallicities
is caused by a process, or processes, whose effect was determined at the
formation time of GCs. This process (or processes) is historically termed the
`second parameter', metallicity being the `first parameter'. We then argue that
the `planet second parameter' model, where the presence of planets and to a
lesser degree brown dwarfs and low mass main sequence stars is the `second
parameter', fits this conjecture.Comment: 11 pages, 4 figures, submitted to MNRA
Classification of Planetary Nebulae by their Departure from Axisymmetry
We propose a scheme to classify planetary nebulae (PNe) according to their
departure from axisymmetric structure. We consider only departure along and
near the equatorial plane, i.e., between the two sides perpendicular to the
symmetry axis of the nebula. We consider 6 types of departure from axisymmetry:
(1) PNe whose central star is not at the center of the nebula; (2) PNe having
one side brighter than the other; (3) PNe having unequal size or shape of the
two sides; (4) PNe whose symmetry axis is bent, e.g., the two lobes in bipolar
PNe are bent toward the same side; (5) PNe whose main departure from
axisymmetry is in the outer regions, e.g., an outer arc; (6) PNe which show no
departure from axisymmetry, i.e., any departure, if it exists, is on scales
smaller than the scale of blobs, filaments, and other irregularities in the
nebula. We discuss the connection between departure types and the physical
mechanisms that may cause them, mainly due to the influence by a stellar binary
companion. We find that about 50 percents of all PNe possess large-scale
departure from axisymmetry. This number is larger than that expected from the
influence of binary companions, namely 25-30 percents. We argue that this
discrepancy comes from many PNe whose departure from axisymmetry, mainly
unequal size, shape, or intensity, results from the presence of long-lived and
large, hot or cool, spots on the surface of their AGB progenitors. Such spots
locally enhance mass loss rate, leading to a deparure from axisymmetry, mainly
near the equator, in the descendant PN.Comment: 10 pages + 1 table. Submitted to MNRA
Recent smell loss is the best predictor of COVID-19 among individuals with recent respiratory symptoms
In a preregistered, cross-sectional study we investigated whether olfactory loss is a reliable predictor of COVID-19 using a crowdsourced questionnaire in 23 languages to assess symptoms in individuals self-reporting recent respiratory illness. We quantified changes in chemosensory abilities during the course of the respiratory illness using 0-100 visual analog scales (VAS) for participants reporting a positive (C19+; n=4148) or negative (C19-; n=546) COVID-19 laboratory test outcome. Logistic regression models identified univariate and multivariate predictors of COVID-19 status and post-COVID-19 olfactory recovery. Both C19+ and C19- groups exhibited smell loss, but it was significantly larger in C19+ participants (mean±SD, C19+: -82.5±27.2 points; C19-: -59.8±37.7). Smell loss during illness was the best predictor of COVID-19 in both univariate and multivariate models (ROC AUC=0.72). Additional variables provide negligible model improvement. VAS ratings of smell loss were more predictive than binary chemosensory yes/no-questions or other cardinal symptoms (e.g., fever). Olfactory recovery within 40 days of respiratory symptom onset was reported for ~50% of participants and was best predicted by time since respiratory symptom onset. We find that quantified smell loss is the best predictor of COVID-19 amongst those with symptoms of respiratory illness. To aid clinicians and contact tracers in identifying individuals with a high likelihood of having COVID-19, we propose a novel 0-10 scale to screen for recent olfactory loss, the ODoR-19. We find that numeric ratings ≤2 indicate high odds of symptomatic COVID-19 (4<10). Once independently validated, this tool could be deployed when viral lab tests are impractical or unavailable
More than smell - COVID-19 is associated with severe impairment of smell, taste, and chemesthesis
Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, generally lacked quantitative measurements, were mostly restricted to data from single countries. Here, we report the development, implementation and initial results of a multi-lingual, international questionnaire to assess self-reported quantity and quality of perception in three distinct chemosensory modalities (smell, taste, and chemesthesis) before and during COVID-19. In the first 11 days after questionnaire launch, 4039 participants (2913 women, 1118 men, 8 other, ages 19-79) reported a COVID-19 diagnosis either via laboratory tests or clinical assessment. Importantly, smell, taste and chemesthetic function were each significantly reduced compared to their status before the disease. Difference scores (maximum possible change+/-100) revealed a mean reduction of smell (-79.7+/- 28.7, mean+/- SD), taste (-69.0+/- 32.6), and chemesthetic (-37.3+/- 36.2) function during COVID-19. Qualitative changes in olfactory ability (parosmia and phantosmia) were relatively rare and correlated with smell loss. Importantly, perceived nasal obstruction did not account for smell loss. Furthermore, chemosensory impairments were similar between participants in the laboratory test and clinical assessment groups. These results show that COVID-19-associated chemosensory impairment is not limited to smell, but also affects taste and chemesthesis. The multimodal impact of COVID-19 and lack of perceived nasal obstruction suggest that SARS-CoV-2 infection may disrupt sensory-neural mechanisms.Additional co-authors: Veronica Pereda-Loth, Shannon B Olsson, Richard C Gerkin, Paloma Rohlfs DomÃnguez, Javier Albayay, Michael C. Farruggia, Surabhi Bhutani, Alexander W Fjaeldstad, Ritesh Kumar, Anna Menini, Moustafa Bensafi, Mari Sandell, Iordanis Konstantinidis, Antonella Di Pizio, Federica Genovese, Lina Öztürk, Thierry Thomas-Danguin, Johannes Frasnelli, Sanne Boesveldt, Özlem Saatci, Luis R. Saraiva, Cailu Lin, Jérôme Golebiowski, Liang-Dar Hwang, Mehmet Hakan Ozdener, Maria Dolors Guà rdia, Christophe Laudamiel, Marina Ritchie, Jan HavlÃcek, Denis Pierron, Eugeni Roura, Marta Navarro, Alissa A. Nolden, Juyun Lim, KL Whitcroft, Lauren R. Colquitt, Camille Ferdenzi, Evelyn V. Brindha, Aytug Altundag, Alberto Macchi, Alexia Nunez-Parra, Zara M. Patel, Sébastien Fiorucci, Carl M. Philpott, Barry C. Smith, Johan N Lundström, Carla Mucignat, Jane K. Parker, Mirjam van den Brink, Michael Schmuker, Florian Ph.S Fischmeister, Thomas Heinbockel, Vonnie D.C. Shields, Farhoud Faraji, Enrique Enrique SantamarÃa, William E.A. Fredborg, Gabriella Morini, Jonas K. Olofsson, Maryam Jalessi, Noam Karni, Anna D'Errico, Rafieh Alizadeh, Robert Pellegrino, Pablo Meyer, Caroline Huart, Ben Chen, Graciela M. Soler, Mohammed K. Alwashahi, Olagunju Abdulrahman, Antje Welge-Lüssen, Pamela Dalton, Jessica Freiherr, Carol H. Yan, Jasper H. B. de Groot, Vera V. Voznessenskaya, Hadar Klein, Jingguo Chen, Masako Okamoto, Elizabeth A. Sell, Preet Bano Singh, Julie Walsh-Messinger, Nicholas S. Archer, Sachiko Koyama, Vincent Deary, Hüseyin Yanik, Samet Albayrak, Lenka Martinec Novákov, Ilja Croijmans, Patricia Portillo Mazal, Shima T. Moein, Eitan Margulis, Coralie Mignot, Sajidxa Mariño, Dejan Georgiev, Pavan K. Kaushik, Bettina Malnic, Hong Wang, Shima Seyed-Allaei, Nur Yoluk, Sara Razzaghi, Jeb M. Justice, Diego Restrepo, Julien W Hsieh, Danielle R. Reed, Thomas Hummel, Steven D Munger, John E Haye
The U1 snRNP Base Pairs with the 5′ Splice Site within a Penta-snRNP Complex
Recognition of the 5′ splice site is an important step in mRNA splicing. To examine whether U1 approaches the 5′ splice site as a solitary snRNP or as part of a multi-snRNP complex, we used a simplified in vitro system in which a short RNA containing the 5′ splice site sequence served as a substrate in a binding reaction. This system allowed us to study the interactions of the snRNPs with the 5′ splice site without the effect of other cis-regulatory elements of precursor mRNA. We found that in HeLa cell nuclear extracts, five spliceosomal snRNPs form a complex that specifically binds the 5′ splice site through base pairing with the 5′ end of U1. This system can accommodate RNA-RNA rearrangements in which U5 replaces U1 binding to the 5′ splice site, a process that occurs naturally during the splicing reaction. The complex in which U1 and the 5′ splice site are base paired sediments in the 200S fraction of a glycerol gradient together with all five spliceosomal snRNPs. This fraction is functional in mRNA spliceosome assembly when supplemented with soluble nuclear proteins. The results argue that U1 can bind the 5′ splice site in a mammalian preassembled penta-snRNP complex
The 'Second Parameter': a memory from the globular cluster formation epoch
Submitted to MNRASConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7 Rome; International School for Advanced Studies, Via Beirut, 7 Trieste / CNR - Consiglio Nazionale delle RichercheSIGLEITItal
A framework for systematic conservation planning and management of Mediterranean landscapes
Active and dynamic management of biodiversity is of utmost importance in the face of increasing human pressures on nature. Current approaches for site selection of protected areas often assume that both conservation features and management actions are fixed in space and time. However, this approach should be revised to allow for spatio-temporal shifts of biodiversity features, threats and management options. Our aim here was to demonstrate a novel approach for systematic conservation planning at a fine scale that incorporates dynamic ecological processes (e.g., succession), biodiversity targets and management costs. We used the new 'Marxan with Zones' decision support tool to spatially redistribute the major structural types of vegetation within a privately-owned nature park in Israel and facilitate the achievement of multiple conservation targets for minimum cost. The park is located in the Mediterranean climate region of the eastern Mediterranean Basin, one of Earth's richest biodiversity hotspots. This small park alone (4.5 km(2)) holds 660 species of native plants and six structural types of vegetation. The region has been subject to manifold human pressures such as grazing, clearing and fire for millennia and is currently threatened by a range of modern human-related activities (e.g., invasive alien species). By spatially redistributing the six structural vegetation types under three scenarios, representing different conservation objectives (no change, equal distribution - evenness of structural types, preference to early succession stages) within three budget frameworks, we identified a set of near-optimal conservation strategies that can be enacted over time. The current spatial distribution of structural types and the cost of changing one structural type into another via management actions had a major impact on the spatial prioritization outcomes and management recommendations. Notably, an advanced successional stage (dense Mediterranean garrigue) tended to dominate a large portion of the landscape when the available budgets were low because it is a relatively inexpensive structural type to maintain. The approach presented here can be further applied to spatially prioritize conservation goals in the face of shifting environments and climates, allowing dynamic conservation planning at multiple spatial scales. (C) 2012 Elsevier Ltd. All rights reserved
Exploring Per- and Polyfluoroalkyl Substances (PFAS) in Microestuaries: Occurrence, Distribution, and Risks
Microestuaries have a crucial role in supporting biodiversity
and
human life quality in heavily populated areas. They are also the last
barrier controlling fluxes of pollutants from the land to sea. Here,
we report the occurrence and distribution of per- and polyfluoroalkyl
substances (PFAS) during the dry season in three microestuaries. The
total PFAS concentration (n = 12) at the studied
estuaries was very high from a global perspective with maximum and
median concentrations of 17.4 and 3.4 μg L–1, respectively. These concentrations significantly exceed the recommended
benchmarks for recreational activity. Our analysis reveals that a
major fraction of PFAS originated from wastewater effluents, whereas
point source pollution dominated when the estuary met an industrial
zone containing refinery facilities. In the case of limited dilution
by natural riverine water, we suggest using carbamazepine as a steady
indicator for the identification of PFAS originating from wastewater.
Although the three studied microestuaries exhibit similar characteristics
(morphology, precipitation, watershed size, water volume, etc.), changes
in water input and connectivity to the sea, along with local anthropogenic
activity, dramatically alter the occurrence, concentrations, and distribution
of PFAS. This study suggests that microestuaries are subjected to
high ecological risk from PFAS pollution due to intensive anthropogenic
activity
IHH enhancer variant within neighboring NHEJ1 intron causes microphthalmia anophthalmia and coloboma
Abstract Genomic sequences residing within introns of few genes have been shown to act as enhancers affecting expression of neighboring genes. We studied an autosomal recessive phenotypic continuum of microphthalmia, anophthalmia and ocular coloboma, with no apparent coding-region disease-causing mutation. Homozygosity mapping of several affected Jewish Iranian families, combined with whole genome sequence analysis, identified a 0.5 Mb disease-associated chromosome 2q35 locus (maximal LOD score 6.8) harboring an intronic founder variant in NHEJ1, not predicted to affect NHEJ1. The human NHEJ1 intronic variant lies within a known specifically limb-development enhancer of a neighboring gene, Indian hedgehog (Ihh), known to be involved in eye development in mice and chickens. Through mouse and chicken molecular development studies, we demonstrated that this variant is within an Ihh enhancer that drives gene expression in the developing eye and that the identified variant affects this eye-specific enhancer activity. We thus delineate an Ihh enhancer active in mammalian eye development whose variant causes human microphthalmia, anophthalmia and ocular coloboma. The findings highlight disease causation by an intronic variant affecting the expression of a neighboring gene, delineating molecular pathways of eye development