139 research outputs found
Economic Reforms, Financial Development and Growth: Lessons from the Chilean Experience
No full textDespite reform efforts, the economic performance of Latin American countries during the 1990s was disappointing with the exception of Chile, which grew at almost 7% per year. This paper tries to explain this difference. Following recent literature that hiEconomic growth, reforms, institutions, financial development
The supracondylar process in the skeletal remains of a full-term fetus from Central Spain (V–VII century BC)
No full textA rare case in the remains of a full-term fetus was recovered from the archaeological site 'Arriaca-Zaide' (Guadalajara, Spain) that dates to the century V-VII BC. The right humerus presents an osseous tubercle, fractured at its end that extends obliquely forward and medially, from the anteromedial aspect of the lower third of the humerus. It is a supracondylar process, a rare osseous anatomic variation. The presence of the supracondylar process in the fetal period allowed us to propose its congenital nature. Furthermore, its disposition and state of ossification allowed us to suggest that it was formed from the ossification center of the humeral diaphysis and not from a secondary ossification center. This case represents the first time that the supracondylar process during the fetal period has been described in the anthropological physical literature.Banco de Santander/Universidad Complutense de MadridDepto. de Anatomía y EmbriologíaFac. de MedicinaTRUEpu
The Icebreaker Mission to Search for Life on Mars
No full textThe search for evidence of life on Mars is the ultimate motivation for its scientific exploration. The results from the Phoenix mission indicate that the high N. latitude ice-rich regolith at low elevations is likely to be a recently habitable place on Mars [Stoker et al., 2010]. The near-surface ice likely provided adequate water activity during periods of high obliquity, 3 to 10 Myr ago. Carbon dioxide and nitrogen are present in the atmosphere, and nitrates may be present in the soil. Together with iron in basaltic rocks and perchlorate in the soil they provide carbon and energy sources, and oxidative power to drive metabolism. Furthermore, the presence of organics is possible, as thermally reactive perchlorate would have prevented their detection by Viking and Phoenix. The Mars Icebreaker Life mission [McKay et al., 2013] focuses on the following science goals: (1) Search for biomolecular evidence of life; (2) Search for organic matter from either exogeneous or endogeneous sources using methods that are not effected by the presence of perchlorate; (3) Characterize oxidative species that produced reactivity of soils seen by Viking; and 4) Assess the habitability of the ice bearing soils. The Icebreaker Life payload (Figure 1) includes a 1-m rotary percussive drill that brings cuttings samples to the surface where they are delivered to three instruments (Fig. 1), the Signs of Life Detector (SOLID) [Parro et al., 2011] for biomolecular analysis, Laser Desorption Mass Spectrometer (LDMS) [??? 2015]) for broad spectrum organic analysis, and Wet Chemistry Laboratory (WCL) [Hecht et al., 2009] for detecting soluble species of nutrients and reactive oxidants. The Icebreaker payload fits on the Phoenix spacecraft and can land at the well-characterized Phoe-nix landing site in 2020 in a Discovery-class mission
Microarray analysis of defined Mycobacterium tuberculosis populations using RNA amplification strategies.
No full textBACKGROUND: The amplification of bacterial RNA is required if complex host-pathogen interactions are to be studied where the recovery of bacterial RNA is limited. Here, using a whole genome Mycobacterium tuberculosis microarray to measure cross-genome representation of amplified mRNA populations, we have investigated two approaches to RNA amplification using different priming strategies. The first using oligo-dT primers after polyadenylation of the bacterial RNA, the second using a set of mycobacterial amplification-directed primers both linked to T7 polymerase in vitro run off transcription.
RESULTS: The reproducibility, sensitivity, and the representational bias introduced by these amplification systems were examined by contrasting expression profiles of the amplified products from inputs of 500, 50 and 5 ng total M. tuberculosis RNA with unamplified RNA from the same source. In addition, as a direct measure of the effectiveness of bacterial amplification for identifying biologically relevant changes in gene expression, a model M. tuberculosis system of microaerophilic growth and non-replicating persistence was used to assess the capability of amplified RNA microarray comparisons. Mycobacterial RNA was reproducibly amplified using both methods from as little as 5 ng total RNA (~equivalent to 2 x 105 bacilli). Differential gene expression patterns observed with unamplified RNA in the switch from aerobic to microaerophilic growth were also reflected in the amplified expression profiles using both methods.
CONCLUSION: Here we describe two reproducible methods of bacterial RNA amplification that will allow previously intractable host-pathogen interactions during bacterial infection to be explored at the whole genome level by RNA profiling
Detecting life on Mars and the life marker chip : antibody assays for detecting organic molecules in liquid extracts of Martian samples
No full textThe Life Marker Chip instrument, which has been selected to fly as part of the 2018
ExoMars rover mission payload, aims to detect up to 25 organic molecules in martian
rocks and regolith, as markers of extant life, extinct life, meteoritic in-fall and spacecraft
contamination. Martian samples will be extracted with a solvent and the resulting liquid
extracts will be analysed using multiplexed microarray-format immunoassays. The LMC
is under development by an international consortium led by the University of Leicester
and the work described within this thesis was carried out at Cranfield University as part
of the consortium’s broader program of work preparing the LMC instrument for flight in
2018. Within this thesis four specific areas of LMC instrument development are
addressed: the investigation of immunoassay compatible liquid extraction solvents, the
study of likely interactions of martian sample matrix with immunoassays, the
development of antibodies for the detection of markers of extinct life and demonstration
of solvent extraction and immunoassay detection in a flight representative format. Cont/d
Author Correction: The geology and evolution of the Near-Earth binary asteroid system (65803) Didymos
No full textBarnouin, Olivier S. et al.-- Full list of authors: Barnouin, Olivier; Ballouz, Ronald-Louis; Marchi, Simone; Vincent, Jean-Baptiste; Agrusa, Harrison; Zhang, Yun; Ernst, Carolyn M.; Pajola, Maurizio; Tusberti, Filippo; Lucchetti, Alice; Daly, R. Terik; Palmer, Eric; Walsh, Kevin J.; Michel, Patrick; Sunshine, Jessica M.; Rizos, Juan L.; Farnham, Tony L.; Richardson, Derek C.; Parro, Laura M.; Murdoch, Naomi; Robin, Colas Q.; Hirabayashi, Masatoshi; Kahout, Tomas; Asphaug, Erik; Raducan, Sabina D.; Jutzi, Martin; Ferrari, Fabio; Hasselmann, Pedro Henrique Aragao; CampoBagatin, Adriano; Chabot, Nancy L.; Li, Jian-Yang; Cheng, Andrew F.; Nolan, Michael C.; Stickle, Angela M.; Karatekin, Ozgur; Dotto, Elisabetta; Della Corte, Vincenzo; Mazzotta Epifani, Elena; Rossi, Alessandro; Gai, Igor; Deshapriya, Jasinghege Don Prasanna; Bertini, Ivano; Zinzi, Angelo; Trigo-Rodriguez, Josep M.; Beccarelli, Joel; Ivanovski, Stavro Lambrov; Brucato, John Robert; Poggiali, Giovanni; Zanotti, Giovanni; Amoroso, Marilena; Capannolo, Andrea; Cremonese, Gabriele; Dall'Ora, Massimo; Ieva, Simone; Impresario, Gabriele; Lavagn, Michèle; Modenini, Dario; Palumbo, Pasquale; Perna, Davide; Pirrotta, Simone; Tortora, Paolo; Zannoni, Marco; Rivkin, Andrew S.In this article the funding from the Spanish project PID2021-128062NB-I00 funded by MCIN/AEI
was omitted. The original article has been corrected.Peer reviewe
Immunological detection of small organic molecules in the presence of perchlorates: relevance to the life marker chip and life detection on Mars.
No full textThe proposed ExoMars mission, due to launch in 2018, aims to look for evidence
of extant and extinct life in martian rocks and regolith. Previous attempts to
detect organic molecules of biological or abiotic origin on Mars have been
unsuccessful, which may be attributable to destruction of these molecules by
perchlorate salts during pyrolysis sample extraction techniques. Organic
molecules can also be extracted and measured with solvent-based systems. The
ExoMars payload includes the Life Marker Chip (LMC) instrument, capable of
detecting biomarker molecules of extant and extinct Earth-like life in liquid
extracts of martian samples with an antibody microarray assay. The aim of the
work reported here was to investigate whether the presence of perchlorate salts,
at levels similar to those at the NASA Phoenix landing site, would compromise
the LMC extraction and detection method. To test this, we implemented an LMC-
representative sample extraction process with an LMC-representative antibody
assay and used these to extract and analyze a model sample that consisted of a
Mars analog sample matrix (JSC Mars-1) spiked with a representative organic
molecular target (pyrene, an example of abiotic meteoritic infall targets) in
the presence of perchlorate salts. We found no significant change in immunoassay
function when using pyrene standards with added perchlorate salts. When model
samples spiked with perchlorate salts were subjected to an LMC-representative
liquid extraction, immunoassays functioned in a liquid extract and detected
extracted pyrene. For the same model sample matrix without perchlorate salts, we
observed anomalous assay signals that coincided with yellow coloration of the
extracts. This unexpected observation is being studied further. This initial
study indicates that the presence of perchlorate salts, at levels similar to
those detected at the NASA Phoenix landing site, is unlikely to prevent the LMC
from extracting and detecting organic molecules from martian samples
The Signs of Life Detector (SOLID): An Instrument to Detect Molecular Biosignatures on Mars
No full textThe case for life on Mars grows stronger. Investigations at Gale Crater by Curiosity have revealed fine-grained sedimentary rocks inferred to represent an ancient lake environment suited to support life. In addition, Curiosity tentatively found a heterogeneous distribution of organic carbon within these sediments, consistent with the detection of native organic C in Mars meteorites. Furthermore, modern potentially habitable environments have been recognized on Mars including the N. Polar region visited by Phoenix, gully features suggesting modern water flows, and RSLs that occur seasonally suggest liquid processes. The time is ripe for missions to Mars incorporating a search for biochemical evidence of life
Author Correction: Unprecedented rains decimate surface microbial communities in the hyperarid core of the Atacama Desert (Scientific Reports, (2018), 8, 1, (16706), 10.1038/s41598-018-35051-w)
No full textThis Article contains typographical errors in the Results section where, “Massive parallel sequencing of 16S ribosomal RNA gene amplicons showed that more than 60% of the sequences found in the lagoons belonged to only four main OTUs (Operational Taxonomical Units), specifically to the Class Gammaproteobacteria: Halomonas (found worldwide20), Marinimicrobium, Marinobacter and Acinetobacter (Table 1). A decrease in biodiversity is observed as the salinity of the lagoons increase (Table 1), revealing the higher salinity tolerance of Marinimicrobium and Marinobacter species compared to that of Halomonas and Acinetobacter species here reported.” should read: “Massive parallel sequencing of 16S ribosomal RNA gene amplicons showed that more than 60% of the sequences found in the lagoons belonged to only four main OTUs (Operational Taxonomical Units), specifically to the Class Gammaproteobacteria: Halomonas (found worldwide20), Marinimicrobium, Marinobacter and Acinetobacter (Table 2). A decrease in biodiversity is observed as the salinity of the lagoons increase (Table 2), revealing the higher salinity tolerance of Marinimicrobium and Marinobacter species compared to that of Halomonas and Acinetobacter species here reported.”. © 2019, The Author(s).Universidad Autónoma de Chil
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