24 research outputs found
The impact of neos and their fragments recorded from the ground : ongoing research lines of the spanish fireball network
A continuous monitoring of the night sky all over Spain will be completed in 2009. This involves the recording over a
very large surface area of 500,000 km2, but new CCD and video cameras operated by the Spanish Meteor and Fireball
Network (SPMN) allows this target to be achieved. Through the use of these new techniques the SPMN can obtain new
information regarding the dynamical processes that deliver meteorites to the Earth. It transpires that the main asteroid
belt is not the only source of these fireballs, Near Earth Objects (NEOs) and Jupiter Family Comets (JFCs) may also
play a role. To obtain more information in this regard, new efforts are needed to compare the orbits of large meteoroids
reaching the Earth with those of the members of NEO and JFC populations. By numerically integrating their orbits back
in time it may be possible to identify meteoroids delivered by other mechanisms like such as catastrophic disruptions or
collisions
The Villalbeto de la Peña meteorite fall: I. Fireball energy, meteorite recovery, strewn field, and petrography
An impressive daylight fireball was observed from Spain, Portugal, and the south of France at 16h46m45s UTC on January 4, 2004. The meteoroid penetrated into the atmosphere, generating shock waves that reached the ground and produced audible booms. The associated airwave was recorded at a seismic station located 90 km north of the fireball trajectory in Spain, and at an infrasound station in France located 750 km north-east of the fireball. The absolute magnitude of the bolide has been determined to be -18 ± 1 from a casual video record. The energy released in the atmosphere determined from photometric, seismic, and infrasound data was about 0.02 kilotons (kt). A massive fragmentation occurred at a height of 28 ± 0.2 km, resulting in a meteorite strewn field of 20 ± 6 km. The first meteorite specimen was found on January 11, 2004, near the village of Villalbeto de la Pena, in northern Palencia (Spain). To date, about 4.6 kg of meteorite mass have been recovered during several recovery campaigns. The meteorite is a moderately shocked (S4) L6 ordinary chondrite with a cosmic-ray-exposure age of 48 ± 5 Ma. Radioisotope analysis shows that the original body had a mass of 760 ± 150 kg, which is in agreement with the estimated mass obtained from photometric and seismic measurements
The Traspena meteorite: heliocentric orbit, atmospheric trajectory, strewn field, and petrography of a new L5 ordinary chondrite
The Traspena meteorite fell on 2021 January 18 about 20 km south-east of the city of Lugo (Galiza, Spain), shortly after a huge and bright fireball crossed the sky for 4.84 s. Astrometric measurements obtained from the fireball cameras of the Universidade de Santiago de Compostela (USC) as well as from many casual videos were used to determine the atmospheric trajectory of this meteoroid which penetrated the atmosphere and generated sound waves that were detected at three seismic stations. The original meteoroid had a diameter of about 1.15 m and a mass around 2620 kg. It impacted the Earth’s atmosphere with a steep entry angle of about 76 . ◦7 from a height of 75.10 km until fading away at 15.75 km with a velocity of 2.38 km s −1 . Before the impact, this small asteroid was orbiting the Sun with a semimajor axis of 1.125 au, a moderate eccentricity of 0.386, and a low inclination of 4 . ◦55. A weak evidence of dynamic link with the PHA (Potential Hazardous Asteroid) Minos was investigated. During the atmospheric entry, two major fragmentation events occurred between heights of 35 and 29 km at aerodynamic pressures between 1 and 5 MPa. The strewn field was computed after calculating the individual dark flights of the main body along with two smaller fragments. For- tunately, 2 month after the superbolide, a 527-g meteorite was found. It was examined using several geochemical and petrographic analyses which allowed us to classify it as a moderately shocked (S3) L5 ordinary chondrite with a bulk density of 3.25 g cm −3 .This paper was supported by the Xunta de Galicia (Spain) under the ED431B 2020/38 grant.Peer reviewe
Effectiveness of Fosfomycin for the Treatment of Multidrug-Resistant Escherichia coli Bacteremic Urinary Tract Infections
IMPORTANCE The consumption of broad-spectrum drugs has increased as a consequence of the spread of multidrug-resistant (MDR) Escherichia coli. Finding alternatives for these infections is critical, for which some neglected drugs may be an option. OBJECTIVE To determine whether fosfomycin is noninferior to ceftriaxone or meropenem in the targeted treatment of bacteremic urinary tract infections (bUTIs) due to MDR E coli. DESIGN, SETTING, AND PARTICIPANTS This multicenter, randomized, pragmatic, open clinical trial was conducted at 22 Spanish hospitals from June 2014 to December 2018. Eligible participants were adult patients with bacteremic urinary tract infections due to MDR E coli; 161 of 1578 screened patients were randomized and followed up for 60 days. Data were analyzed in May 2021. INTERVENTIONS Patients were randomized 1 to 1 to receive intravenous fosfomycin disodium at 4 g every 6 hours (70 participants) or a comparator (ceftriaxone or meropenem if resistant; 73 participants) with the option to switch to oral fosfomycin trometamol for the fosfomycin group or an active oral drug or pa renteral ertapenem for the comparator group after 4 days. MAIN OUTCOMES AND MEASURES The primary outcome was clinical and microbiological cure (CMC) 5 to 7 days after finalization of treatment; a noninferiority margin of 7% was considered. RESULTS Among 143 patients in the modified intention-to-treat population (median [IQR] age, 72 [62-81] years; 73 [51.0%] women), 48 of 70 patients (68.6%) treated with fosfomycin and 57 of 73 patients (78.1%) treated with comparators reached CMC (risk difference, -9.4 percentage points; 1-sided 95% CI, -21.5 to infinity percentage points; P = .10). While clinical or microbiological failure occurred among 10 patients (14.3%) treated with fosfomycin and 14 patients (19.7%) treated with comparators (risk difference, -5.4 percentage points; 1-sided 95% CI. -infinity to 4.9; percentage points; P = .19), an increased rate of adverse event-related discontinuations occurred with fosfomycin vs comparators (6 discontinuations [8.5%] vs 0 discontinuations; P = .006). In an exploratory analysis among a subset of 38 patients who underwent rectal colonization studies, patients treated with fosfomycin acquired a new ceftriaxone-resistant or meropenem-resistant gram-negative bacteria at a decreased rate compared with patients treated with comparators (0 of 21 patients vs 4 of 17 patients [23.5%]; 1-sided P = .01). CONCLUSIONS AND RELEVANCE This study found that fosfomycin did not demonstrate noninferiority to comparators as targeted treatment of bUTI from MDR E coli; this was due to an increased rate of adverse event-related discontinuations. This finding suggests that fosfomycin may be considered for selected patients with these infections
A bright fireball witnessed on august, 17, 2011 over the Iberian Peninsula
The detailed study of bright fireball
events is one of the aims of the SPanish Meteor Net-
work (SPMN), as these allow
us to collect very valu-
able information on the origin of the relatively rare
meteorite-dropping bolides. In this context, a very
bright fireball (at least mag. -12) was observed over
the Iberian Peninsula during the evening twilight of
August 17, 2011. However, unfavourable weather
conditions in most of the regions where our meteor
observing stations were working did not allow us to
record any video or image of this fireball. Fortunately,
because of excellent weat
her over Galicia and other
areas in northwest Spain, the observation of this event
was very favourable for numerous visual witnesses
that could account for it. These were interviewed by a
team belonging to the
Ramón María Aller Astronomi-
cal Observatory
(OARMA). This made possible a reli-
able reconstruction of the fireball trajectory in a sys-
tematic way as made in previous events [see e.g. 3].
We present here the preliminar
y analysis of this event.
The data provided by the eyewitnesses reveal that, in
fact, this could have been a meteorite-dropping fire-
ball, although the meteorite would have landed on the
Atlantic Ocea
Erratum: “On the Orbital Elements of the Two-body Problem with Slowly Decreasing Mass: The Gyldén–Mestchersky Cases” (2020, AJ, 160, 203)
In Abad et al., we studied the time evolution of orbital elements in the so-called “Gyldén–Mestchersky cases.” Actually the plots represent the evolution of orbital elements with respect to the eccentric anomaly, related with time through Kepler’s equation. When reproducing figures with respect to time, they are globally similar to the ones we obtained but with slight differences, as T. Kramer informed us. In this note we aim to amend the errors in the figure captions and also to explain the way we computed orbital elements, in particular the eccentricity, by means of a continuous explicit function of the mean anomaly, with no need to solve Kepler’s equation at each instant of the time interval
Observation of three twilight bolides in August, 2013 from Galicia, NW of Spain
The Spanish Meteor Network
(SPMN) is dedicated to the study of fireballs and bolides
which may cause meteorite falls on our planet.
These meteorites allow us a better understanding of
other bodies from the Solar System and that is why we
operate 25 meteor observing stations to monitor the
night sky.
During the month of August 2013, three bright bolides
were observed from the northwest of the Iberian
Peninsula, on days 14, 22, and 30. The first one was
recorded by the camera from the R. M. Aller Astronomical
Observatory (OARMA). There were numerous
visual witnesses that could account for them and
the atmospheric path of one the bolides was reconstructed
from the observation provided by them and
the images of the camera.
In this work we present the data provided by the
witnesses (for all three cases) and a preliminary analysis
of one of these events (day 14)
Analisys of a datyme fireball witnessed on August 10, 2012 over the Iberian Peninsula
Meteorite-dropping bolides are rare
events that may provide unique samples coming from
other bodies in the Solar System. For this reason, the
analysis of such events is one of the aims of the SPanish
Meteor Network (SPMN), which is currently operating
25 meteor and fireball observing stations to
monitor the night sky. In the evening of August 10,
2012, about half an our before sunset, a very bright
fireball (at least mag. -14) was witnessed over the
northwest of the Iberian Peninsula. The event took
place under daylight conditions and, so, before our
detection systems started operation. However, its observation
was very favourable for numerous visual
witnesses that could account for it. So, despite no images
were recorded, the atmospheric path of the bolide
could be reconstructed from the observation provided
by these. In this work we present a preliminary analysis
of this event. Our calculations reveal that, in fact,
this fireball could have produced a meteorite, although
this would have landed on the Cantabrian Sea
ORBIT AND SYSTEM MASS FOR THE VISUAL BINARY WDS 23186+6807AB
ABSTRACT A revised orbit, with period of 1505 yr, and system mass, 3.65 AE 0.60 M , are presented for the visual binary WDS 23186+6807AB. The total mass is well in accord with estimates from the literature made on the basis of different methods. The G8 III spectral type of the primary is confirmed