158 research outputs found
Preliminary analysis of genetic variation of Escallonia alpina and E. rubra
Escallonia alpina y E. rubra (Escalloniaceae) comparten su área de distribución en el sur de los Andes y se diferencian por pocos caracteres morfológicos diagnósticos, tales como la disposición de las flores y la presencia y tipo de glándulas; sin embargo, en algunas poblaciones no es posible asignar los individuos a una u otra especie. Además, se han reconocido y descrito como híbridos varias formas de transición entre ambas. El objetivo de este trabajo es examinar la variabilidad genética poblacional de Escallonia alpina y E. rubra, y analizar si se corresponde con la variabilidad morfológica observada. Se estudió la morfología en 39 individuos de cinco poblaciones sobre los que también se realizó un análisis de AFLP. Se investigó la relación entre los individuos mediante análisis de ordenación, agrupamiento y de asignación bayesiana. Además se calcularon índices de diversidad y se realizó una prueba de Mantel. A partir del análisis morfológico, se asignaron dos poblaciones a cada especie, mientras que una población con individuos con morfología intermedia no se pudo asignar unívocamente a ninguna de las dos especies. Se observó una fuerte correspondencia entre las especies delimitadas mediante caracteres morfológicos diagnósticos tradicionales y el patrón de AFLP. La evidencia morfológica y molecular preliminar nos permitió reconocer a Escallonia alpina y E. rubra como dos especies distintas, y a una población con caracteres morfológicos y genéticos intermedios que podrían ser el resultado de flujo génico interespecífico o de una separación incompleta de linajes.Escallonia alpina and E. rubra (Escalloniaceae) are distributed in the same geographical region in the southern Andes; they are differentiated by few diagnostic morphological characters such as flower arrangement, and type and presence of glands. A morphological gap between both species is absent in some populations; in addition, intermediate forms have been recognized and described as hybrids. The aim of this work is to examine the genetic variation in populations of Escallonia alpina and E. rubra, and to analyze if there is a correspondence between genetic and morphological variability. We studied the morphology of 39 individuals belonging to five populations, which were also used to perform an AFLP analysis. We conducted ordination, clustering and Bayesian assignment analyses to investigate the relationship among individuals, and we calculated genetic diversity indices and a Mantel test. As a result of the morphological analysis, two populations were assigned to each species, while the remaining population could not be assigned unequivocally to any of the two species, as the individuals exhibited an intermediate morphology. A strong correspondence between traditional morphological characters and the AFLP pattern was observed. Our preliminary morphological and molecular evidence support Escallonia alpina and E. rubra as two distinct species. The variability found in the intermediate population might be the result of inter-specific hybridization or incomplete lineage sorting.Fil: Morello, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion (i); Argentina;Fil: Giussani, Liliana Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion (i); Argentina;Fil: Sede, Silvana Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion (i); Argentina
Hunter-gatherers, biogeographic barriers and the development of human settlement in Tierra del Fuego
Tierra del Fuego represents the southernmost limit of human settlement in the Americas. While people may have started to arrive there around 10 500 BP, when it was still connected to the mainland, the main wave of occupation occurred 5000 years later, by which time it had become an island. The co-existence in the area of maritime hunter-gatherers(in canoes) with previous terrestrial occupants pre-echoes the culturally distinctive groups encountered by the first European visitors in the sixteenth century. The study also provides a striking example of interaction across challenging natural barriers
High-fidelity operation and algorithmic initialisation of spin qubits above one kelvin
The encoding of qubits in semiconductor spin carriers has been recognised as
a promising approach to a commercial quantum computer that can be
lithographically produced and integrated at scale. However, the operation of
the large number of qubits required for advantageous quantum applications will
produce a thermal load exceeding the available cooling power of cryostats at
millikelvin temperatures. As the scale-up accelerates, it becomes imperative to
establish fault-tolerant operation above 1 kelvin, where the cooling power is
orders of magnitude higher. Here, we tune up and operate spin qubits in silicon
above 1 kelvin, with fidelities in the range required for fault-tolerant
operation at such temperatures. We design an algorithmic initialisation
protocol to prepare a pure two-qubit state even when the thermal energy is
substantially above the qubit energies, and incorporate high-fidelity
radio-frequency readout to achieve an initialisation fidelity of 99.34 per
cent. Importantly, we demonstrate a single-qubit Clifford gate fidelity of
99.85 per cent, and a two-qubit gate fidelity of 98.92 per cent. These advances
overcome the fundamental limitation that the thermal energy must be well below
the qubit energies for high-fidelity operation to be possible, surmounting a
major obstacle in the pathway to scalable and fault-tolerant quantum
computation
Is it really advantageous to operate proximal femoral fractures within 48 h from diagnosis? – A multicentric retrospective study exploiting COVID pandemic-related delays in time to surgery
Objectives: Hip fractures in the elderly are common injuries that need timely surgical management. Since the beginning of the pandemic, patients with
a proximal femoral fracture (PFF) experienced a delay in time to surgery. The primary aim of this study was to evaluate a possible variation in mortality
in patients with PFF when comparing COVID-19 negative versus positive.
Methods: This is a multicentric and retrospective study including 3232 patients with PFF who underwent surgical management. The variables
taken into account were age, gender, the time elapsed between arrival at the emergency room and intervention, pre-operative American Society of
Anesthesiology score, pre-operative cardiovascular and respiratory disease, and 10-day/1-month/6-month mortality. For 2020, we had an additional
column, “COVID-19 swab positivity.”
Results: COVID-19 infection represents an independent mortality risk factor in patients with PFFs. Despite the delay in time-to-surgery occurring in
2020, no statistically significant variation in terms of mortality was detected. Within our sample, a statistically significant difference was not detected in
terms of mortality at 6 months, in patients operated within and beyond 48 h, as well as no difference between those operated within or after 12/24/72 h.
The mortality rate among subjects with PFF who tested positive for COVID-19 was statistically significantly higher than in patients with PFF who
tested. COVID-19 positivity resulted in an independent factor for mortality after PFF.
Conclusion: Despite the most recent literature recommending operating PFF patients as soon as possible, no significant difference in mortality was
found among patients operated before or after 48 h from diagnosis
Enabling planetary science across light-years. Ariel Definition Study Report
Ariel, the Atmospheric Remote-sensing Infrared Exoplanet Large-survey, was adopted as the fourth medium-class mission in ESA's Cosmic Vision programme to be launched in 2029. During its 4-year mission, Ariel will study what exoplanets are made of, how they formed and how they evolve, by surveying a diverse sample of about 1000 extrasolar planets, simultaneously in visible and infrared wavelengths. It is the first mission dedicated to measuring the chemical composition and thermal structures of hundreds of transiting exoplanets, enabling planetary science far beyond the boundaries of the Solar System. The payload consists of an off-axis Cassegrain telescope (primary mirror 1100 mm x 730 mm ellipse) and two separate instruments (FGS and AIRS) covering simultaneously 0.5-7.8 micron spectral range. The satellite is best placed into an L2 orbit to maximise the thermal stability and the field of regard. The payload module is passively cooled via a series of V-Groove radiators; the detectors for the AIRS are the only items that require active cooling via an active Ne JT cooler. The Ariel payload is developed by a consortium of more than 50 institutes from 16 ESA countries, which include the UK, France, Italy, Belgium, Poland, Spain, Austria, Denmark, Ireland, Portugal, Czech Republic, Hungary, the Netherlands, Sweden, Norway, Estonia, and a NASA contribution
Measurement of ZZ production in leptonic final states at {\surd}s of 1.96 TeV at CDF
In this paper we present a precise measurement of the total ZZ production
cross section in pp collisions at {\surd}s= 1.96 TeV, using data collected with
the CDF II detector corresponding to an integrated luminosity of approximately
6 fb-1. The result is obtained by combining separate measurements in the
four-charged (lll'l'), and two-charged-lepton and two-neutral-lepton (llvv)
decay modes of the Z. The combined measured cross section for pp {\to} ZZ is
1.64^(+0.44)_(-0.38) pb. This is the most precise measurement of the ZZ
production cross section in 1.96 TeV pp collisions to date.Comment: submitted to Phys. Rev. Let
Measurement of ϒ production in pp collisions at √s = 2.76 TeV
The production of ϒ(1S), ϒ(2S) and ϒ(3S)
mesons decaying into the dimuon final state is studied with
the LHCb detector using a data sample corresponding to an
integrated luminosity of 3.3 pb−1 collected in proton–proton
collisions at a centre-of-mass energy of √s = 2.76 TeV. The
differential production cross-sections times dimuon branching
fractions are measured as functions of the ϒ transverse
momentum and rapidity, over the ranges pT < 15 GeV/c
and 2.0 < y < 4.5. The total cross-sections in this kinematic
region, assuming unpolarised production, are measured to be
σ (pp → ϒ(1S)X) × B
ϒ(1S)→μ+μ−
= 1.111 ± 0.043 ± 0.044 nb,
σ (pp → ϒ(2S)X) × B
ϒ(2S)→μ+μ−
= 0.264 ± 0.023 ± 0.011 nb,
σ (pp → ϒ(3S)X) × B
ϒ(3S)→μ+μ−
= 0.159 ± 0.020 ± 0.007 nb,
where the first uncertainty is statistical and the second systematic
HE-LHC: The High-Energy Large Hadron Collider: Future Circular Collider Conceptual Design Report Volume 4
In response to the 2013 Update of the European Strategy for Particle Physics (EPPSU), the Future Circular Collider (FCC) study was launched as a world-wide international collaboration hosted by CERN. The FCC study covered an energy-frontier hadron collider (FCC-hh), a highest-luminosity high-energy lepton collider (FCC-ee), the corresponding 100 km tunnel infrastructure, as well as the physics opportunities of these two colliders, and a high-energy LHC, based on FCC-hh technology. This document constitutes the third volume of the FCC Conceptual Design Report, devoted to the hadron collider FCC-hh. It summarizes the FCC-hh physics discovery opportunities, presents the FCC-hh accelerator design, performance reach, and staged operation plan, discusses the underlying technologies, the civil engineering and technical infrastructure, and also sketches a possible implementation. Combining ingredients from the Large Hadron Collider (LHC), the high-luminosity LHC upgrade and adding novel technologies and approaches, the FCC-hh design aims at significantly extending the energy frontier to 100 TeV. Its unprecedented centre-of-mass collision energy will make the FCC-hh a unique instrument to explore physics beyond the Standard Model, offering great direct sensitivity to new physics and discoveries
FCC-ee: The Lepton Collider: Future Circular Collider Conceptual Design Report Volume 2
In response to the 2013 Update of the European Strategy for Particle Physics, the Future Circular Collider (FCC) study was launched, as an international collaboration hosted by CERN. This study covers a highest-luminosity high-energy lepton collider (FCC-ee) and an energy-frontier hadron collider (FCC-hh), which could, successively, be installed in the same 100 km tunnel. The scientific capabilities of the integrated FCC programme would serve the worldwide community throughout the 21st century. The FCC study also investigates an LHC energy upgrade, using FCC-hh technology. This document constitutes the second volume of the FCC Conceptual Design Report, devoted to the electron-positron collider FCC-ee. After summarizing the physics discovery opportunities, it presents the accelerator design, performance reach, a staged operation scenario, the underlying technologies, civil engineering, technical infrastructure, and an implementation plan. FCC-ee can be built with today’s technology. Most of the FCC-ee infrastructure could be reused for FCC-hh. Combining concepts from past and present lepton colliders and adding a few novel elements, the FCC-ee design promises outstandingly high luminosity. This will make the FCC-ee a unique precision instrument to study the heaviest known particles (Z, W and H bosons and the top quark), offering great direct and indirect sensitivity to new physics
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