Environment and density-dependency explain the fine-scale aggregation of tree recruits before and after thinning in a mixed forest of Southern Europe.

Thinning in forest management primarily reduces the density of trees and alters the patchiness and spatial complexity of environmental factors and individual interactions between plant recruits. At fine spatial scales, little is known about the relative weight of ecological processes affecting tree regeneration before and after thinning events. Here we studied the density and aggregation of tree recruits in fully-mapped plots located in mixed forests in Northern Iberian Peninsula (Southern Europe) for over four years, which comprises one year before and three years after a thinning event. We applied spatial point-pattern analyses to examine (a) the aggregation of recruits, and their association with trees and (b) the relative effect of both environmental (i.e., the patchiness of the local environment) and density-dependent factors (i.e., the aggregation of trees and/or recruits) to predict the density, aggregation, and survival of recruits. We found, in thinning plots, that recruits were less dense, their aggregation pattern was more heterogeneous, were distributed randomly in respect of trees and their survival was almost unaffected by the tree proximity. By contrast, recruits in control plots were denser, were only aggregated at distances lower than 1.0 m, were closer to trees, and such closer distance to trees affected negatively in their survival. Independently of the treatment, the aggregation of recruits was chiefly determined by the density-dependent factors at less than 1.0 m and environmental factors at distances beyond that proximity. Overall, our results suggest that thinning affected the aggregation of recruits at two spatial scales: (a) by favoring the tree-recruit and recruit-recruit facilitation at less than 1.0 m and (b) by modifying spatial heterogeneity of the environment at distances beyond that proximity.

Parker Solar Probe Imaging of the Night Side of Venus.

We present images of Venus from the Wide-Field Imager for Parker Solar Probe (WISPR) telescope on board the Parker Solar Probe (PSP) spacecraft, obtained during PSP's third and fourth flybys of Venus on 2020 July 11 and 2021 February 20, respectively. Thermal emission from the surface is observed on the night side, representing the shortest wavelength observations of this emission ever, the first detection of the Venusian surface by an optical telescope observing below 0.8 µm. Consistent with previous observations at 1 µm, the cooler highland areas are fainter than the surrounding lowlands. The irradiances measured by WISPR are consistent with model predictions assuming a surface temperature of T = 735 K. In addition to the thermal emission, the WISPR images also show bright nightglow emission at the limb, and we compare the WISPR intensities with previous spectroscopic measurements of the molecular oxygen nightglow lines from Venus Express.

The nightside cloud-top circulation of the atmosphere of Venus.

Although Venus is a terrestrial planet similar to Earth, its atmospheric circulation is much different and poorly characterized1. Winds at the cloud top have been measured predominantly on the dayside. Prominent poleward drifts have been observed with dayside cloud tracking and interpreted to be caused by thermal tides and a Hadley circulation2-4; however, the lack of nightside measurements over broad latitudes has prevented the unambiguous characterization of these components. Here we obtain cloud-tracked winds at all local times using thermal infrared images taken by the Venus orbiter Akatsuki, which is sensitive to an altitude of about 65 kilometres5. Prominent equatorward flows are found on the nightside, resulting in null meridional velocities when these are zonally averaged. The velocity structure of the thermal tides was determined without the influence of the Hadley circulation. The semidiurnal tide was found to have an amplitude large enough to contribute to the maintenance of the atmospheric superrotation. The weakness of the mean meridional flow at the cloud top implies that the poleward branch of the Hadley circulation exists above the cloud top and that the equatorward branch exists in the clouds. Our results should shed light on atmospheric superrotation in other celestial bodies.

Decoupling of traditional burnings and grazing regimes alters plant diversity and dominant species competition in high-mountain grasslands.

Over millennia, the combination of controlled burnings and extensive grazing has maintained mosaic landscapes and preserved mountain grasslands in southern Europe. In the last century, deep socio-economic changes have led to an abandonment of traditional uses, to a general decline of the domestic herbivory and to a misuse of burning practices. This study aims to quantify how the decoupling of burning and grazing regimes affects in the long-term the structure, diversity and dynamics of high-mountain, shrub-encroached grasslands. In spring 2012, four treatments (burned-grazed, burned-ungrazed, unburned-grazed and unburned-ungrazed) were set up at three sites in the Special Area of Conservation Roncesvalles-Selva de Irati, in southwest Pyrenees. During seven years, we monitored floristic composition and the height of the native tall-grass Brachypodium rupestre in four plots at each site. In the burned plots, we surveyed the resprout of the dominant shrub Ulex gallii and the dynamics of recovering of the herbaceous vegetation. Plant communities evolved differently in grazed and ungrazed plots. Extensive grazing, despite being lower than in previous decades, maintained plant diversity and limited shrub encroachment. The total absence of grazing fostered the encroachment of U. gallii at two sites and the expansion of B. rupestre at the other site. When B. rupestre cover was >60%, the encroachment of U. gallii was reduced. This research highlights the competition that occurs between shrubs and tall-grasses in the absence of grazing, and the modulating effect exerted by the burnings and the site-specific features. Understanding local plant dynamics is the first step to design the most appropriate practices that help to preserve diversity at the landscape and the community level in high-mountain grasslands of south Europe.

How waves and turbulence maintain the super-rotation of Venus' atmosphere.

Venus has a thick atmosphere that rotates 60 times as fast as the surface, a phenomenon known as super-rotation. We use data obtained from the orbiting Akatsuki spacecraft to investigate how the super-rotation is maintained in the cloud layer, where the rotation speed is highest. A thermally induced latitudinal-vertical circulation acts to homogenize the distribution of the angular momentum around the rotational axis. Maintaining the super-rotation requires this to be counteracted by atmospheric waves and turbulence. Among those effects, thermal tides transport the angular momentum, which maintains the rotation peak, near the cloud top at low latitudes. Other planetary-scale waves and large-scale turbulence act in the opposite direction. We suggest that hydrodynamic instabilities adjust the angular-momentum distribution at mid-latitudes.

Venus looks different from day to night across wavelengths: morphology from Akatsuki multispectral images.

Since insertion into orbit on December 7, 2015, the Akatsuki orbiter has returned global images of Venus from its four imaging cameras at eleven discrete wavelengths from ultraviolet (283 and 365 nm) and near infrared (0.9-2.3 µm), to the thermal infrared (8-12 µm) from a near-equatorial orbit. The Venus Express and Pioneer Venus Orbiter missions have also monitored the planet for long periods but from polar or near-polar orbits. The wavelength coverage and views of the planet also differ for all three missions. In reflected light, the images reveal features seen near the cloud tops (~ 70 km altitude), whereas in the near-infrared images of the nightside, features seen are at mid- to lower cloud levels (~ 48-60 km altitude). The dayside cloud cover imaged at the ultraviolet wavelengths shows morphologies similar to what was observed from Mariner 10, Pioneer Venus, Galileo, Venus Express and MESSENGER. The daytime images at 0.9 and 2.02 µm also reveal some interesting features which bear similarity to the ultraviolet images. The nighttime images at 1.74, 2.26 and 2.32 µm and at 8-12 µm reveal features not seen before and show new details of the nightside including narrow wavy ribbons, curved string-like features, long-scale waves, long dark streaks, isolated bright spots, sharp boundaries and even mesoscale vortices. Some features previously seen such as circum-equatorial belts (CEBs) and occasional areal brightenings at ultraviolet (seen in Venus Express observations) of the cloud cover at ultraviolet wavelengths have not been observed thus far. Evidence for the hemispheric vortex organization of the global circulation can be seen at all wavelengths on the day- and nightsides. Akatsuki images reveal new and puzzling morphology of the complex nightside cloud cover. The cloud morphologies provide some clues to the processes occurring in the atmosphere and are thus, a key diagnostic tool when quantitative dynamical analysis is not feasible due to insufficient information.

Comparative performance of the protocol of plasma rich in growth factors - universal 1 (PRGF-U1) for obtaining platelet rich plasma

Objective: to compare the platelet concentration obtained after application of the protocol of plasma rich in growth factors - universal 1 (PRGF-U1) and the protocol of Anitua and Andia (PRP-A) for obtaining platelet rich plasma. Material and Method: A descriptive, cross-sectional and comparative study was carried out with a simple random probabilistic sample consisting of 16 patients who attended the Periodontics service of the Unit of Second Specialization in Stomatology of the National University of Trujillo. Five blood samples were obtained from each patient, after applying a health questionnaire to rule out any disease or drug consumption, in order to obtain the baseline platelet concentration and that obtained after PRGF-U1 and PRP-A. To compare the platelet concentrations of the two protocols, Student’s t-test was used considering a significance level of p<0.05. RESULTS: The baseline platelet concentration was 371,250 +/- 68,203 platelets/ μL, for PRGF-U1 it was 747,875 +/- 121,645 platelets/μL and for PRP-A it was 595,000 +/- 129,202 platelets/ML. A statistically significant difference (p<0.001) was found between both protocols. Conclusion: The PRGF-U1 protocol yielded a higher platelet concentration compared to the Anitua and Andia protocol.

Equatorial jet in the lower to middle cloud layer of Venus revealed by Akatsuki.

The Venusian atmosphere is in a state of superrotation where prevailing westward winds move much faster than the planet's rotation. Venus is covered with thick clouds that extend from about 45 to 70 km altitude, but thermal radiation emitted from the lower atmosphere and the surface on the planet's night-side escapes to space at narrow spectral windows of near-infrared. The radiation can be used to estimate winds by tracking the silhouettes of clouds in the lower and middle cloud regions below about 57 km in altitude. Estimates of wind speeds have ranged from 50 to 70 m/s at low- to mid-latitudes, either nearly constant across latitudes or with winds peaking at mid-latitudes. Here we report the detection of winds at low latitude exceeding 80 m/s using IR2 camera images from the Akatsuki orbiter taken during July and August 2016. The angular speed around the planetary rotation axis peaks near the equator, which we suggest is consistent with an equatorial jet, a feature that has not been observed previously in the Venusian atmosphere. The mechanism producing the jet remains unclear. Our observations reveal variability in the zonal flow in the lower and middle cloud region that may provide new challenges and clues to the dynamics of Venus's atmospheric superrotation.

Detection of allergen sources in the homes of sensitized children.

OBJECTIVE: To identify the presence of environmental factors linked to the onset of allergies and asthma in the homes of children participating in an early detection program that were identified with sensitivity to common allergens in the region of Sonora, Mexico. METHODS: A walkthrough assessment was carried out in the homes of sensitized children; the research tools were the questionnaire and environmental checklist proposed by the Lowell Healthy Homes Program of the University of Massachusetts-Lowell. RESULTS: The results showed the presence of environmental allergen sources, to which most of the children in the study are sensitized, as well as the environmental conditions and habits that determine the quality of the indoor air of the households, were both related to triggering allergies and asthma in this population. A statistically significant association was found between the visual observation of dust inside homes and the sensitivity of children to dust mites. CONCLUSIONS: Dust found inside the home was the most relevant environmental factor related to positive cases of IgE in children. Early detection of allergies in children in the study and the methodology used in this investigation provided a useful framework for the design of plans and intervention alternatives in these homes to prevent the development of allergies and asthma panorama. These plans should be designed with a multidisciplinary approach to impact social, environmental and economic benefits in the family, improving the living conditions of the study population and contributing to the sustainable development goals of the United Nations for 2030.

Estudio retrospectivo de la evolución de las fracturas de meseta tibial tratadas en el Hospital del Lídice / I study retrospective of the evolution of the fractures of tibial plateau tried in the Hospital de Lídice

Se realizó una revisión de 26 pacientes, que fueron tratados en el Hospital General Dr. Jesús Yerena, entre enero de 1997 y diciembre de 2001, por presentar fracturas de mesetas tibiales, quienes fueron resultados ortopédicamente o quirúrgicamente luego de una estancia prolongada de hospitalización, debido a problemas socioeconómicos, y se estudió cual fue la evolución posterior de estos al tratamiento definitivo aplicado. Se obtuvieron resultados que revelaron la importancia de resolver estos casos a la brevedad posible, para reducir el número de aplicaciones inherentes a esta patología altamente incapacitante.