Objetivo.
Evaluar el impacto de las intervenciones introducidas en Costa Rica durante 2020 y 2021 para el control de la pandemia por COVID-19.
Método.
Se empleó un modelo bayesiano de regresión de ...Poisson que incorporó las medidas de control o intervención como variables independientes sobre la modificación de la cantidad de casos por semana epidemiológica.
Resultados.
Los resultados evidenciaron el efecto relativo y conjunto que han tenido las políticas o medidas de contención en la reducción de casos, principalmente la restricción vehicular, el uso de mascarillas y la puesta en práctica de los lineamientos y protocolos sanitarios. Las evidencias de los efectos se optimizaron y se pusieron a disposición para la toma de decisiones de las autoridades sanitarias y de emergencia del país. Se generaron varias iteraciones para el monitoreo constante de la variación en los efectos en cuatro momentos distintos del avance de la pandemia.
Conclusión.
La aplicación simultánea de distintas medidas de mitigación en Costa Rica ha sido un agente promotor de la disminución de casos de COVID-19.
A
bstract
We use the gauge gravity correspondence to study the renormalization group flow of a double trace fermionic operator in a quark-gluon plasma subject to the influence of a strong magnetic ...field and compare it with the results for the case at zero temperature and no magnetic field, where the flow between two fixed points is observed. Our results show that the energy necessary to access the physics of the ultraviolet theory increases with the intensity of the magnetic field under which the processes happen. We provide arguments to support that this increase is scheme independent, and to exhibit further evidence we do a very simple calculation showing that the dimensional reduction expected in the gauge theory in this scenario is effective up to an energy scale that grows with the strength of such a background field. We also show that independently of the renormalization scheme, the coupling of the double trace operators in the ultraviolet fixed point increases with the intensity of the background field. These effects combined can change both, the processes that are expected to be involved in a collision experiment at a given energy and the azimuthal anisotropy of the measurements resulting of them.
A long-standing goal in plant breeding has been the ability to confer apomixis to agriculturally relevant species, which would require a deeper comprehension of the molecular basis of apomictic ...regulatory mechanisms. Eragrostis curvula (Schrad.) Nees is a perennial grass that includes both sexual and apomictic cytotypes. The availability of a reference transcriptome for this species would constitute a very important tool toward the identification of genes controlling key steps of the apomictic pathway. Here, we used Roche/454 sequencing technologies to generate reads from inflorescences of E. curvula apomictic and sexual genotypes that were de novo assembled into a reference transcriptome. Near 90% of the 49568 assembled isotigs showed sequence similarity to sequences deposited in the public databases. A gene ontology analysis categorized 27448 isotigs into at least one of the three main GO categories. We identified 11475 SSRs, and several of them were assayed in E curvula germoplasm using SSR-based primers, providing a valuable set of molecular markers that could allow direct allele selection. The differential contribution to each library of the spliced forms of several transcripts revealed the existence of several isotigs produced via alternative splicing of single genes. The reference transcriptome presented and validated in this work will be useful for the identification of a wide range of gene(s) related to agronomic traits of E. curvula, including those controlling key steps of the apomictic pathway in this species, allowing the extrapolation of the findings to other plant species.
Macrobrachium tenellum and M. americanum are common freshwater prawns from the Americas' tropical and subtropical Pacific continental side. They have different biological attributes and are currently ...threatened by human impact on their ecosystems. Both species provide different quality products for human consumption and are intensively exploited without proper management. This study analyzes, discusses, and compares the available information for both species and their current status as a live resource.
A reentrant superconducting effect was observed in YBCO particles as a consequence of their size and microstructure. It rises from the coexistence between bulk superconductivity and surface ...ferromagnetism, where the enhanced magneto-electric coupling induced by broken spatial-inversion symmetry in layers near structural defects plays a very important role on surface ferromagnetism. The study assumes grain boundaries inside the particles act as additional surface regions that enhance the ferromagnetic properties. Magnetic and superconducting properties as a function of particle size were studied. Particularly, the 385 nm particles which were the ones that exhibited the reentrant superconducting effect. The Ginzburg–Landau parameter and the critical temperatures are
k
∼
1.29
±
.
03
,
T
c
1
=
92
±
0.5
K
, and
T
c
2
≈
10
±
3
K
.
Six dinuclear organotin building blocks of general composition RR′R′′SnCH2Si(CH3)2−biphenyl−Si(CH3)2CH2SnR′′R′R, in which the tin atoms are separated by a p,p′‐biphenylene bridge and carry different ...substituents BD1 with R, R′=CH2Si(CH3)3, R′′=Ph; BD2 with R, R′=CH2Si(CH3)3, R′′=Cl; BD3, with R, R′=CH2Si(CH3)3, R′′=I; BD4 with R=CH2Si(CH3)2(C5H4FeCp), R′, R′′=Ph; BD5 with R=CH2Si(CH3)2(C5H4FeCp), R′=Ph, R”=Cl; BD6 with R=CH2Si(CH3)2(C5H4FeCp), R′=Ph, R′′=I, were synthesized and characterized by spectroscopic and spectrometric methods. Furthermore, the crystal and molecular structures of BD2 were determined by single‐crystal X‐ray diffraction (SCXRD) analysis, revealing the formation of molecular strands through intermolecular Cl→Sn contacts. The 1D coordination polymer BD2n comprises macrocyclic rings of composition BD22 that motivated the generation of a related molecular macrocyclic structure by reaction of BD2 with silver (I) oxide in a 2 : 2 stoichiometry. The 2+2 macrocyclization yielded the 30‐membered tetra‐nuclear ring structure M1, viz., {R2SnCH2Si(CH3)2−biphenyl−(CH3)2SiCH2SnR2(μ‐O)}2, in which two BD2 dinuclear building blocks are linked through two covalent Sn−O−Sn moieties. Examination by DFT calculations at the B3LYP/def2svp and B3LYP/6‐31G*(C,H,O,Si)/LanL2DZ(Sn) levels of theory gave energy minima for molecular conformers of M1 carrying the Sn−O−Sn and p,p′‐biphenylene bridges in syn‐ or anti‐orientation.
Dinuclear organotin halides carrying CH2SiMe3 and ferrocenyl‐substituents were prepared and found suitable for the synthesis of a tetra‐nuclear 30‐membered macrocycle via fusion through Sn−O−Sn bridges.
The superconductor FeSe0.5Te0.5 was studied with Point Contact spectroscopy and specific heat in polycrystalline samples. The transition temperature determined by magnetic measurement was TC=14.5K. ...The size of the energy gap measured by junctions is Δ=1.9meV, whereas the gap determined by the specific heat measurements was Δ=2.3meV. The gap evolution with temperature follows BCS, the ratio 2Δ/KBTC has values between 2.88 ≤2Δ/KBTC≤3.04. The compound was grown by solid state synthesis in quartz ampoules under vacuum at 950°C. Crystal structure was characterized by X-ray diffraction. The superconducting properties were characterized by magnetization, resistivity and specific heat. This superconductor shows an isotropic energy gap as observed with the fitting of the specific heat at low temperature.
•Point contact and tunneling spectroscopies in FeSe superconductor.•Energy gap and critical temperature.•Analysis with BTK model.•Strong coupling superconductors.
Macrobrachium tenellum is a freshwater prawn native from Mexico to Peru, with potential for cultivation. Currently, it is extensively exploited by local fisheries. To understand its chitin ...requirements, a formulated diet with chitin added (5, 10 15, 2D, and 25%) was given to juveniles for 60 days. Growth, survival, and enzyme activity (trypsin, chymotrypsin, lipase, amylase, and chitinase) were measured every 15 days. Highest final weight and specific growth rate resulted from diets with 20% chitin. Poorest performance resulted from diets with 5 and 10% chitin. Chitin in the diet did not have a significant effect on survival. Statistically significant differences in enzyme activity were not found in any treatment.
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