Interaction strength between different grazers and macroalgae mediated by ocean acidification over warming gradients

Since the past century, rising CO2 levels have led to global changes (ocean warming and acidification) with subsequent effects on marine ecosystems and organisms. Macroalgae-herbivore interactions have a main role in the regulation of marine community structure (top-down control). Gradients of warming prompt complex non-linear effects on organism metabolism, cascading into altered trophic interactions and community dynamics. However, not much is known on how will acidification and grazer assemblage composition shape these effects. Within this context, we aimed to assess the combined effects of warming gradients and acidification on macroalgae-herbivore interactions, using three cosmopolitan species, abundant in the Iberian Peninsula and closely associated in nature: the amphipod Melita palmata, the gastropod Gibbula umbilicalis, and the green macroalga Ulva rigida. Under two CO2 treatments (triangle CO2 similar or equal to 450 mu atm) across a temperature gradient (13.5, 16.6, 19.9 and 22.1 degrees C), two mesocosm experiments were performed to assess grazer consumption rates and macroalgae-herbivore interaction, respectively. Warming (Experiment I and II) and acidification (Experiment II) prompted negative effects in grazer's survival and species-specific differences in consumption rates. M. palmata was shown to be the stronger grazer per biomass (but not per capita), and also the most affected by climate stressors. Macroalgae-herbivore interaction strength was markedly shaped by the temperature gradient, while simultaneous acidification lowered thermal optimal threshold. In the near future, warming and acidification are likely to strengthen top-down control, but further increases in disturbances may lead to bottom-up regulated communities. Finally, our results suggest that grazer assemblage composition may modulate future macroalgae-herbivore interactions. (C) 2017 Elsevier Ltd. All rights reserved.Peer reviewe

Influencia de la fermentación y secado en la germinación de la semilla de papaya (carica papaya l.).

El ensayo se realizó en la Granja Experimental de la Universidad del Magdalena, localizada en el Municipio de Santa Marta; la granja se encuentra ubicada a una altura de 7 m.s.n.m., con temperatura promedio de 28°C, precipitación anual de 680mm y humedad relativa de 70%. Los objetos bajo los cuales se realizó el ensayo consistieron en determinar cuál era el mejor tratamiento para obtener el más alto porcentaje de germinación en la semilla de Papaya, Determinar el mejor 'tratamiento bajo las condiciones del experimento para obtener el más alto porcentaje de germinación, Determinar la viabilidad en cada uno de los tratamientos mediante la prueba del Tetrazolio (Cloruro de 2,3,5 - Trifenil Tetrazol). Comparar la germinación in vitro y en el germinador bajo las condiciones de la investigación

The influence of heavy goods vehicle traffic on accidents on different types of Spanish interurban roads

This paper illustrates a methodology developed to analyze the influence of traffic conditions, i.e. volume and composition on accidents on different types of interurban roads in Spain, by applying negative binomial models. The annual average daily traffic was identified as the most important variable, followed by the percentage of heavy goods vehicles, and different covariate patterns were found for each road type. The analysis of hypothetical scenarios of the reduction of heavy goods vehicles in two of the most representative freight transportation corridors, combined with hypotheses of total daily traffic mean intensity variation, produced by the existence or absence of induced traffic gives rise to several scenarios. In all cases a reduction in the total number of accidents would occur as a result of the drop in the number of heavy goods transport vehicles, However the higher traffic intensity, resulting of the induction of other vehicular traffic, reduces the effects on the number of accidents on single carriageway road segments compared with high capacity roads, due to the increase in exposure. This type of analysis provides objective elements for evaluating policies that encourage modal shifts and road safety enhancements

Single-Exciton Amplified Spontaneous Emission in Thin Films of CsPbX3 (X = Br, I) Perovskite Nanocrystals

CsPbX3 perovskite nanocrystals (PNCs) have emerged as an excellent material for stimulated emission purposes, with even more prospective applications than conventional colloidal quantum dots. However, a better understanding of the physical mechanisms responsible for amplified spontaneous emission (ASE) is required to achieve more ambitious targets (lasing under continuous wave optical or electrical excitation). Here, we establish the intrinsic mechanisms underlying ASE in PNCs of three different band gaps (CsPbBr3, CsPbBr1.5I1.5, and CsPbI3). Our characterization at cryogenic temperatures does not reveal any evidence of the biexciton mechanism in the formation of ASE. Instead, the measured shift toward long wavelengths of the ASE band is easily explained by the reabsorption in the PNC layer, which becomes stronger for thicker layers. In this way, the threshold of ASE is determined only by optical losses at a given geometry, which is the single-exciton mechanism responsible for ASE. Experimental results are properly reproduced by a physical model

Recycled Photons Traveling Several Millimeters in Waveguides Based on CsPbBr3 Perovskite Nanocrystals

Reabsorption and reemission of photons, or photon recycling (PR) effect, represents an outstanding mechanism to enhance the carrier and photon densities in semiconductor thin films. This work demonstrates the propagation of recycled photons over several mm by integrating a thin film of CsPbBr3 nanocrystals into a planar waveguide. An experimental set-up based on a frequency modulation spectroscopy allows to characterize the PR effect and the determination of the effective decay time of outcoupled photons. A correlation between the observed photoluminescence redshift and the increase of the effective decay time is demonstrated, which grows from 3.5 to near 9 ns in the best device. A stochastic Monte Carlo model reproduces these experimental results and allows the extraction of the physical mechanisms involved. In the waveguide under study recycled photons follow a drift (directional enhancement) velocity ≈5.7 × 105 m s−1, dominating over the diffusive regime observed in a standard thin film (D ≈ 420 m2 s−1). This means that recycled photons propagate mm-distances in shorter traveling times in the waveguide (≈5 ns) as compared to the film (>20 ns). These results are expected to pave the road for exploiting the PR effect in future optoelectronic and photonic devices

Energy Evaluation of Pumping Systems in a Clean Water Plant: A Study Case

This paper presents a methodology based on the ISO-50001 standard to assess the energy impact of replacing standard efficiency motors with high-efficiency motors driven by variable speed drives in an industrial pumping system. The methodology includes the inspection and installation of the new technology, measurements, and data processing, as well as the analysis of the results. In addition, an energy efficiency indicator, an energy baseline, and a Pareto diagram are used, while the harmonics generated by new technologies are evaluated. The contribution of the methodology is that it allows for a comprehensive energy diagnosis using easily measurable data like electricity consumption and water flow, replacing the measurement of the motor\u27s mechanical power in industrial conditions, which is a current challenge. The methodology applied in the case study showed that the technological changes made saved 36% of energy, and that the variable speed drives increased current harmonics by 10%

Cultura organizacional y modelos mentales: estudio de caso en una universidad de la ciudad de Medellín

Las organizaciones funcionan a partir de contextos en donde personas en múltiples roles y niveles se relacionan, lo cual, a su vez, establece una serie de complejidades que median en dicha relación, determinando, entre otros aspectos, la cultura y los modelos mentales. Las universidades no son ajenas a esta cuestión, de allí que resulte relevante analizar cómo cultura y modelos mentales impactan la gestión en estas instituciones, al tiempo que definen la forma de hacer las cosas a partir de paradigmas preestablecidos. El presente estudio plantea un análisis en esta línea, usando como referente la metodología OCAI, aplicada en una universidad de la ciudad de Medellín, obteniendo como resultado más relevante la identificación de los tipos de cultura presentes en dicha institución, así como el análisis de la influencia de la cultura en los procesos académicos y administrativos; de igual manera, se encuentra que, según la revisión teórica, dicha cultura esta mediada por un modelo mental organizacional como paradigma dominante. Como conclusión principal, se tiene que tanto cultura como clima organizacional, están mediados por la manera como las personas perciben el tipo de liderazgo y la forma de comunicar las ideas por parte de los directivos

Reducing Nurse to Patient Ratio

https://scholarlycommons.baptisthealth.net/cohort-5-ebp-showcase/1020/thumbnail.jp

Quality assurance in radiotherapy: analysis of the causes of not starting or early radiotherapy withdrawal.

BACKGROUND: The aim of this study was to analyse the reasons for not starting or for early of radiotherapy at the Radiation Oncology Department. METHODS: All radiotherapy treatments from March 2010 to February 2012 were included. Early withdrawals from treatment those that never started recorded. Clinical, demographic and dosimetric variables were also noted. RESULTS: From a total of 3250 patients treated and reviewed, 121 (4%) did not start or complete the planned treatment. Of those, 63 (52%) did not receive any radiotherapy fraction and 58 (48%) did not complete the course, 74% were male and 26% were female. The mean age was 67 ± 13 years. The most common primary tumour was lung (28%), followed by rectum (16%). The aim of treatment was 62% radical and 38% palliative, 44% of patients had metastases; the most common metastatic site was bone, followed by brain. In 38% of cases (46 patients) radiotherapy was administered concomitantly with chemotherapy (10 cases (22%) were rectal cancers). The most common reason for not beginning or for early withdrawal of treatment was clinical progression (58/121, 48%). Of those, 43% died (52/121), 35 of them because of the progression of the disease and 17 from other causes. Incomplete treatment regimens were due to toxicity (12/121 (10%), of which 10 patients underwent concomitant chemotherapy for rectal cancer). CONCLUSIONS: The number of patients who did not complete their course of treatment is low, which shows good judgement in indications and patient selection. The most common reason for incomplete treatments was clinical progression. Rectal cancer treated with concomitant chemotherapy was the most frequent reason of the interruption of radiotherapy for toxicity