A severe air quality degradation event occurred in the Santiago Metropolitan Area (SMA), Chile, in June 2014. Meteorological and air quality measurements from 11 stations in the area as well as ...numerical simulations using the Weather and Research Forecasting (WRF) model were used to explain the main reasons for the occurrence of elevated particulate matter (PM) concentrations. The conditions were characterized with formation of a coastal low in central Chile between the southeastern anticyclone and a high-pressure system over Argentina. At a local scale, these conditions generated a depression at the base of the inversion layer, an increase in the vertical thermal stability, lower humidity and low-wind conditions, which were conducive to a decrease in pollutant dispersion and insufficient ventilation of the polluted air. Measurements and simulations using the WRF model revealed a vertical structure of the boundary layer during these stagnant conditions and provided a basis for a trajectory analysis. The back-trajectory calculation showed that the transport of air parcels was contained in the valley during the highest concentrations. The analysis also enabled the definition of the threshold values of a simple indicator of air pollution (ventilation coefficient, VC), which confirmed the evolution of the episode and divided the observed daily concentrations into two groups, with one including values above the limits prescribed by the national air quality standards (NAQS) and the other including values below these limits. For the SMA, the daily PM concentrations above the NASQ limits were associated with an overall mean threshold value of VC below 500 m2 s−1 (for PM2.5) and 300 m2 s−1 (for PM10). To apply the VC analysis to other pollutants and different geographic locations, different threshold values should be evaluated.
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•Air pollution episode over complex terrain of Santiago is investigated.•Hourly concentrations exceeded 600 (PM10) and 500 μg m−3 (PM2.5), respectively.•Episode is divided into 3 phases: 1-prior, 2-during, and 3-after the maximum levels.•Back-trajectories, PBL heights and the ventilation coefficients (VC) are modeled.•VC values are grouped to below 500 (Phase 2) and above 500 m2 s−1 (Phases 1 and 3).
A severe pollution episode in a metropolitan area placed in a complex terrain was caused by stagnant conditions, which was corroborated by low modeled values of the planetary boundary layer height and ventilation coefficient.
The production of proteins in sufficient amounts is key for their study or use as biotherapeutic agents. Escherichia coli is the host of choice for recombinant protein production given its fast ...growth, easy manipulation, and cost‐effectiveness. As such, its protein production capabilities are continuously being improved. Also, the associated tools (such as plasmids and cultivation conditions) are subject of ongoing research to optimize product yield. In this work, we review the latest advances in recombinant protein production in E. coli.
GEMS is an IRAM 30m Large Program whose aim is determining the elemental depletions and the ionization fraction in a set of prototypical star-forming regions. This paper presents the first results ...from the prototypical dark cloud TMC 1. Extensive millimeter observations have been carried out with the IRAM 30m telescope (3 mm and 2 mm) and the 40m Yebes telescope (1.3 cm and 7 mm) to determine the fractional abundances of CO, HCO
, HCN, CS, SO, HCS
, and N
H
in three cuts which intersect the dense filament at the well-known positions TMC 1-CP, TMC 1-NH3, and TMC 1-C, covering a visual extinction range from A
~ 3 to ~20 mag. Two phases with differentiated chemistry can be distinguished: i) the translucent envelope with molecular hydrogen densities of 1-5×10
cm
; and ii) the dense phase, located at A
> 10 mag, with molecular hydrogen densities >10
cm
. Observations and modeling show that the gas phase abundances of C and O progressively decrease along the C
/C/CO transition zone (A
~ 3 mag) where C/H ~ 8×10
and C/O~0.8-1, until the beginning of the dense phase at A
~ 10 mag. This is consistent with the grain temperatures being below the CO evaporation temperature in this region. In the case of sulfur, a strong depletion should occur before the translucent phase where we estimate a S/H ~ (0.4 - 2.2) ×10
, an abundance ~7-40 times lower than the solar value. A second strong depletion must be present during the formation of the thick icy mantles to achieve the values of S/H measured in the dense cold cores (S/H ~8×10
). Based on our chemical modeling, we constrain the value of
to ~ (0.5 - 1.8) ×10
s
in the translucent cloud.
High-mass stars and star clusters commonly form within hub-filament systems. Monoceros R2 (hereafter Mon R2), at a distance of 830 pc, harbors one of the closest such systems, making it an excellent ...target for case studies.
We investigate the morphology, stability and dynamical properties of the Mon R2 hub-filament system.
We employ observations of the
CO and C
O 1→0 and 2→1 lines obtained with the IRAM-30m telescope. We also use H
column density maps derived from
dust emission observations.
We identified the filamentary network in Mon R2 with the DisPerSE algorithm and characterized the individual filaments as either main (converging into the hub) or secondary (converging to a main filament) filaments. The main filaments have line masses of 30-100
pc
and show signs of fragmentation, while the secondary filaments have line masses of 12-60
pc
and show fragmentation only sporadically. In the context of Ostriker's hydrostatic filament model, the main filaments are thermally supercritical. If non-thermal motions are included, most of them are trans-critical. Most of the secondary filaments are roughly transcritical regardless of whether non-thermal motions are included or not. From the morphology and kinematics of the main filaments, we estimate a mass accretion rate of 10
-10
yr
into the central hub. The secondary filaments accrete into the main filaments with a rate of 0.1-0.4×10
yr
. The main filaments extend into the central hub. Their velocity gradients increase towards the hub, suggesting acceleration of the gas.We estimate that with the observed infall velocity, the mass-doubling time of the hub is ~ 2:5 Myr, ten times larger than the free-fall time, suggesting a dynamically old region. These timescales are comparable with the chemical age of the Hii region. Inside the hub, the main filaments show a ring- or a spiral-like morphology that exhibits rotation and infall motions. One possible explanation for the morphology is that gas is falling into the central cluster following a spiral-like pattern.
Chip-scale integrated light sources are a crucial component in a broad range of photonics applications. III–V semiconductor nanowire emitters have gained attention as a fascinating approach due to ...their superior material properties, extremely compact size, and capability to grow directly on lattice-mismatched silicon substrates. Although there have been remarkable advances in nanowire-based emitters, their practical applications are still in the early stages due to the difficulties in integrating nanowire emitters with photonic integrated circuits. Here, we demonstrate for the first time optically pumped III–V nanowire array lasers monolithically integrated on silicon-on-insulator (SOI) platform. Selective-area growth of InGaAs/InGaP core/shell nanowires on an SOI substrate enables the nanowire array to form a photonic crystal nanobeam cavity with superior optical and structural properties, resulting in the laser to operate at room temperature. We also show that the nanowire array lasers are effectively coupled with SOI waveguides by employing nanoepitaxy on a prepatterned SOI platform. These results represent a new platform for ultracompact and energy-efficient optical links and unambiguously point the way toward practical and functional nanowire lasers.
Environmental niche modeling (ENM) is commonly used to develop probabilistic maps of species distribution. Among available ENM techniques, MaxEnt has become one of the most popular tools for modeling ...species distribution, with hundreds of peer-reviewed articles published each year. MaxEnt's popularity is mainly due to the use of a graphical interface and automatic parameter configuration capabilities. However, recent studies have shown that using the default automatic configuration may not be always appropriate because it can produce non-optimal models; particularly when dealing with a small number of species presence points. Thus, the recommendation is to evaluate the best potential combination of parameters (feature classes and regularization multiplier) to select the most appropriate model. In this work we reviewed 244 articles published between 2013 and 2015 to assess whether researchers are following recommendations to avoid using the default parameter configuration when dealing with small sample sizes, or if they are using MaxEnt as a "black box tool." Our results show that in only 16% of analyzed articles authors evaluated best feature classes, in 6.9% evaluated best regularization multipliers, and in a meager 3.7% evaluated simultaneously both parameters before producing the definitive distribution model. We analyzed 20 articles to quantify the potential differences in resulting outputs when using software default parameters instead of the alternative best model. Results from our analysis reveal important differences between the use of default parameters and the best model approach, especially in the total area identified as suitable for the assessed species and the specific areas that are identified as suitable by both modelling approaches. These results are worrying, because publications are potentially reporting over-complex or over-simplistic models that can undermine the applicability of their results. Of particular importance are studies used to inform policy making. Therefore, researchers, practitioners, reviewers and editors need to be very judicious when dealing with MaxEnt, particularly when the modelling process is based on small sample sizes.
•Exercise increases plasma BDNF levels in individuals with neurodegenerative disorders.•Effects were consistent for different exercise type, weekly volume, and intervention length.•These findings ...support the benefits of exercise against neurodegenerative disorders.
Neurodegenerative disorders are associated with reduced levels of brain-derived neurotrophic factor (BDNF). We aimed to assess the effect of exercise interventions on plasma BDNF levels in individuals with neurodegenerative disorders. Eighteen randomized controlled trials (RCT) assessing the effects of exercise interventions versus no exercise on plasma BDNF levels in individuals with neurodegenerative disorders (i.e., multiple sclerosis, Parkinson’s disease, mild cognitive impairment MCI and Alzheimer’s disease) were included. Overall, exercise interventions induced a significant increase in plasma BDNF levels (SMD=2.22, 95% CI=1.33–3.12, p<0.001; 18 studies), which was separately confirmed for multiple sclerosis (SMD= 2.40, 95% CI= 1.30–3.50, p<0.001; 10 studies) and Parkinson's disease (SMD= 10.00, 95% CI= 2.48–17.51, p=0.009; 3 studies), with a non-significant trend also observed for MCI (SMD= 1.07, 95% CI= -0.14–2.28, p=0.080; 4 studies). BDNF levels significantly increased regardless of exercise type (p<0.001, p=0.003 and p=0.020 for combined, aerobic and resistance exercise, respectively), weekly exercise volume (p<0.001 for both ≥150 and <150 min/week) and intervention length (p<0.001 for both interventions of ≥12 and <12 weeks). In conclusion, physical exercise interventions increase plasma BDNF levels in individuals with neurodegenerative disorders.
PROSPERO registration number: CRD42020199459.
Background
Nomenclature for mesh insertion during ventral hernia repair is inconsistent and confusing. Several terms, including ‘inlay’, ‘sublay’ and ‘underlay’, can refer to the same anatomical ...planes in the indexed literature. This frustrates comparisons of surgical practice and may invalidate meta‐analyses comparing surgical outcomes. The aim of this study was to establish an international classification of abdominal wall planes.
Methods
A Delphi study was conducted involving 20 internationally recognized abdominal wall surgeons. Different terms describing anterior abdominal wall planes were identified via literature review and expert consensus. The initial list comprised 59 possible terms. Panellists completed a questionnaire that suggested a list of options for individual abdominal wall planes. Consensus on a term was predefined as occurring if selected by at least 80 per cent of panellists. Terms scoring less than 20 per cent were removed.
Results
Voting started August 2018 and was completed by January 2019. In round 1, 43 terms (73 per cent) were selected by less than 20 per cent of panellists and 37 new terms were suggested, leaving 53 terms for round 2. Four planes reached consensus in round 2, with the terms ‘onlay’, ‘inlay’, ‘preperitoneal’ and ‘intraperitoneal’. Thirty‐five terms (66 per cent) were selected by less than 20 per cent of panellists and were removed. After round 3, consensus was achieved for ‘anterectus’, ‘interoblique’, ‘retro‐oblique’ and ‘retromuscular’. Default consensus was achieved for the ‘retrorectus’ and ‘transversalis fascial’ planes.
Conclusion
Consensus concerning abdominal wall planes was agreed by 20 internationally recognized surgeons. Adoption should improve communication and comparison among surgeons and research studies.
Antecedentes
La nomenclatura de la inserción de una malla para la reparación de una hernia incisional ventral (ventral hernia, VH) es inconsistente y confusa. En la literatura indexada se usan varios términos, tales como ‘inlay’, ‘sublay’, y ‘underlay’ que pueden referirse a los mismos planos anatómicos. Este hecho frustra las comparaciones de técnicas quirúrgicas e invalida los metaanálisis que comparan resultados quirúrgicos en función del plano de inserción de la malla. En consecuencia, el objetivo de este estudio fue establecer una clasificación internacional de los planos de la pared abdominal (International Classification of Abdominal Wall Planes, ICAP).
Métodos
Se realizó un estudio Delphi, en el que participaron 20 cirujanos de pared abdominal reconocidos internacionalmente. Se identificaron diferentes términos que describían los planos de la pared abdominal anterior mediante la revisión de la literatura y el consenso de expertos. La lista inicial incluía 59 términos posibles. Los panelistas completaron un cuestionario que sugería una lista de opciones para los planos individuales de la pared abdominal. El consenso sobre un término fue predefinido cuando dicho término había sido seleccionado por ≥ 80% de panelistas. Se eliminaron los términos con una puntuación < 20%.
Resultados
La votación comenzó en agosto de 2018 y se completó en enero de 2019. Durante la Ronda 1, 43 (73%) términos fueron seleccionados por < 20% de los panelistas y se sugirieron 37 términos nuevos, dejando 53 términos para la Ronda 2. Cuatro planos alcanzaron un consenso en la Ronda 2 con los términos ‘onlay’, ‘inlay’, ‘pre‐peritoneal’ e ‘intra‐peritoneal’. Treinta y cinco (66%) términos fueron seleccionados por < 20% de los panelistas y fueron eliminados. Después de la Ronda 3, se logró un consenso para ‘anterectus’ (ante‐recto), ‘interoblique’ (inter‐oblicuo), ‘retrooblique’ (retro‐oblicuo) y ‘retromuscular’. Se alcanzó un consenso por defecto para los planos ‘retrorectus’ (retro‐recto) y ‘transversalis fascial’ (fascial transverso).
Conclusión
La ICAP ha sido desarrollada por el consenso de 20 cirujanos reconocidos internacionalmente. Su implementación debería mejorar la comunicación y la comparación entre cirujanos y estudios de investigación.
Current nomenclature for abdominal wall planes is inconsistent; this confuses clinical practice and frustrates comparative studies. A Delphi study was performed, involving 20 international hernia experts, to define abdominal wall planes precisely. Via consensus, an international classification of abdominal wall planes was established.
Order created by consensus
Water Hyacinth is an invasive aquatic plant with an excellent carbon source with heteroatoms. Activated carbon is a viable choice as an electrocatalyst for fuel cell applications. Based on the ...plant's leaves, stem, and root, we got activated carbons using KOH at 730 °C with N2. The samples, named WH_LA730, WH _SA730, and WH_RA730, were examined as electrocatalysts for oxygen reduction reaction in 0.5 M KOH. The high surface area and nitrogen content in the activated carbon provided a good electrochemical activity. The potential reaction for WH_SA730 was at 0.9 V and 0.85 V for WH_RA730. Both samples showed a promising activated carbon for the alkaline fuel cell compared to WH_LA730.
•Carbon materials were prepared by biomass from “Water Hyacinth.“.•WH_SA730, WH_RA730, and WH_LA730 were evaluated for ORR in an alkaline medium.•The activity toward ORR was favored by high surface area and nitrogen content.
This study analyzed air quality in terms of the concentrations of sub-10 μm (PM
10
) and sub-2.5 μm particulate matter (PM
2.5
) recorded at 23 automated public monitoring stations located in 16 ...cities in south-central Chile (Rancagua, Rengo, San Fernando, Curicó, Talca, Maule, Chillán and Chillán Viejo, Gran Concepción, Coronel, Los Ángeles, Temuco and Padre Las Casas, Valdivia, Osorno, Puerto Montt, Coyhaique, and Punta Arenas). In each city, the spatial and temporal distributions of the PM
10
and PM
2.5
concentrations were recorded at daily, monthly, and yearly intervals. Air quality was evaluated by comparing the annual average concentrations and the maximum daily concentrations of PM
10
and PM
2.5
with the World Health Organization (WHO) and national standards. The results showed that the limits established in the WHO guidelines and the national standards were systematically exceeded at all the study sites. The highest concentrations of both PM
10
and PM
2.5
were observed during the fall and winter months (April to September), i.e., the cold period of the year, whereas the lowest concentrations were recorded in the spring and summer months (October to March), i.e., the warm period of the year. Analysis of variance (ANOVA) of the data collected in the warm and cold periods showed that all stations in this study exhibited statistically significant differences between these two periods. During cold periods, burning firewood for heating produces emissions that are a main source of PM. Furthermore, firewood is primarily burned at night when the lowest temperatures occur and when the atmospheric conditions are generally unfavorable for dispersion; thus, pollution accumulates the above cities. The levels of PM
2.5
, the most important type of pollution, exceeded the limit established by the WHO on at least one third of the days of the year (>120 days) in the cities of Rancagua, Rengo, Curicó, Talca, Chillan, Los Angeles, Temuco, Valdivia, Osorno, Puerto Montt, and Coyhaique. Therefore in the cities in southern Chile, the population is exposed to particulate matter concentrations that can have negative health impacts. To improve the air quality conditions in the studied cities, research on heaters and combustion techniques should be promoted, home energy efficiency should be increased to reduce firewood consumption, the firewood certification process should be improved at the national level with a better auditing processes, and the introduction of alternative fuels should be considered for greater energy efficiency at competitive costs.
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