494 research outputs found
New approaches to the study of Antarctic lithobiontic microorganisms and their inorganic traces, and their application in the detection of life in Martian rocks
Microbial life in the harsh conditions of Antarctica’s cold desert may be considered an analogue of potential life on early Mars. In order to explore the development and survival of this epilithic and endolithic form of microbial life, our most sophisticated, state-ofthe- art visualization technologies have to be used to their full potential. The study of any ecosystem requires a knowledge of its components and the processes that take place within it. If we are to understand the structure and function of each component of the microecosystems that inhabit lithic substrates, we need to be able to quantify and identify the microorganisms present in each lithobiontic ecological niche and to accurately characterize the mineralogical features of these hidden microhabitats. Once we have established the techniques that will allow us to observe and identify these microorganisms and mineral substrates in situ, and have confirmed the presence of water, the following questions can be addressed: How are the microorganisms organized in the fissures or cavities? Which microorganisms are present and how many are there? Additional questions that logically follow include: What are the existing water relationships in the microhabitat and what effects do the microorganisms have on the mineral composition? Mechanical and chemical changes in minerals and mineralization of microbial cells can give rise to physical and/or chemical traces (biomarkers) and to microbial fossil formation. In this report, we describe the detection of chains of magnetite within the Martian meteorite ALH84001, as an example of the potential use of SEMBSE in the search for plausible traces of life on early Mars
Temporal variations in the production—quality and optimal cutting date of hay meadows in the Central Pyrenees (Spain)
The production and forage quality of semi-natural hay meadows of Arrenatheretalia in the southern central Pyrenees were studied according to the time of mowing within the vegetative cycle, to determine its optimum moment. The results show important variations according to the meadows and the year. Higher productions (56% in kg DM ha-1, 42% in UFL ha-1) and lower qualities (-12% in CP, -11% in UFL kg DM-1, -7% in PDI and -17% in RFV) were obtained in the year in which temperatures and rainfalls were the highest. It is concluded that the timing (advance or delay) concerning the maximum value of production and the quality (two years) do not have a direct relationship with the variations of accumulated rainfalls and the growing degree days. The decreases in production (18% in kg DM ha-1 and 25% in UFL ha-1 until 24 June) and quality (26% in CP, 16% in UFL kg DM-1, 13% in PDI and 20% in RFV until 24 June) were also quantified from their maximum values within the traditional mowing period. The optimal time for mowing is between 20 May and 20 June, depending on the annual weather and the meadow characteristics
X-ray diffraction analysis to clarify the unusual origin of an intraocular foreign body
[Purpose]: To clarify the origin of a metallic intraocular foreign body (IOFB) due to a firecracker injury and to show the utility of X-ray diffraction analysis in the identification process. [Methods]: Interventional case report using X-ray diffraction technique. [Results]: We report a mechanism of firecracker ocular injury not previously described in the published literature. It involved penetration into the eye by a ground particle of calamine (originated from the area of detonation) and not, as it could be suspected, by a firecracker fragment. [Conclusion]: X-ray diffraction analysis showed environmental debris in the area of detonation can be injected as foreign material into the eye.Peer Reviewe
Conjunctival Intraepithelial Neoplasia – Clinical Presentation, Diagnosis and Treatment Possibilities
Construction of Chemoenzymatic Linear Cascades for the Synthesis of Chiral Compounds
Inspired by nature, synthetic chemists try to mimic the efficient metabolic networks in living organisms to build complex molecules by combining different types of catalysts in the same reaction vessel. These multistep cascade processes provide many advantages to synthetic procedures, resulting in higher productivities with lower waste generation and cost. However, combining different chemo- and biocatalysts can be challenging as reaction conditions might differ greatly. As a highly multidisciplinary field that benefits from advances in chemical catalysis, molecular biology and reaction engineering, this area of study is rapidly progressing. In this Review, we highlight recent trends and advances in the construction of multistep chemoenzymatic one-pot cascades to access chiral compounds as well as the different strategies to solve current challenges in the field
OLA! A Scenario-Based Approach to Enhance Open Learning Through Accessibility
Open Educational Resources (OER) and Massive Open Online Courses (MOOC) have not developed with an inherent capacity to attend to the needs of disabled students. In our research, we aim to understand the social, contextual and organisational issues behind these inadequacies. Through this, interventions and best practices can be developed to improve the situation
Epidemiology, Etiology, and Prevention of Late IOL-Capsular Bag Complex Dislocation: Review of the Literature
Posterior chamber intraocular lens (PC-IOL) subluxation is uncommon but represents one of the most serious complications following phacoemulsification. Late spontaneous IOL-capsular bag complex dislocation is defined as occurring three months or later following cataract surgery. Unlike early IOL dislocation, late spontaneous IOL dislocation is due to a progressive zonular dehiscence and contraction of the capsular bag many years what seemed to be uneventful surgery. In recent years, late in-the-bag IOL subluxation or dislocation has been reported with increasing frequency, having a cumulative risk of IOL dislocation following cataract extraction of 0.1% after 10 years and 1.7% after 25 years. A predisposition to zonular insufficiency and capsular contraction is identified in 90% of reviewed cases. Multiple conditions likely play a role in contributing to this zonular weakness and capsular contraction. Pseudoexfoliation is the most common risk factor, accounting for more than 50% of cases. Other associated conditions predisposing to zonular dehiscence are aging, high myopia, uveitis, trauma, previous vitreoretinal surgery, retinitis pigmentosa, diabetes mellitus, atopic dermatitis, previous acute angle-closure glaucoma attack, and connective tissue disorders. The recognition of these predisposing factors suggests a modified approach in cases at risk. We review certain measures to prevent IOL-bag complex luxation that have been proposed
Exploración clÃnica en estomatologÃa veterinaria
La exploración clÃnica se basa en un conjunto de normas y maniobras encaminadas al estudio de sÃntomas para la determinación diagnóstica de patologÃas, y al establecimiento de un tratamiento adecuado y especÃfico. Explicamos la exploración sistemática que debe ponerse en práctica en el campo de la EstomatologÃa Veterinaria, pudiendo asà determinar las afecciones de los tejidos blandos y duros.For the diagnostic of different oral pathologies we use several techniques. We will establish a specific treatment for each one. We describe a sistemic exploration that is used in veterinary dentistry and afecting both, soft and hard tissues
Calculation of iris-claw IOL power for correction of late in-the-bag IOL complex dislocation
Background: To assess the constants and formula for aphakia correction with iris-claw IOLs to achieve the best refractive status in cases of late in-the-bag IOL complex dislocation. Methods: A literature search was performed. The following data were obtained: Iris-claw IOL model, Iridal or retroiridal enclavation, A-constant, ultrasound or optical biometry, formula employed and refractive outcomes. Acceptable emmetropia was considered if the resulting spherical equivalent (SE) was within ±1.00 D. Results: The majority of the studies used SRK/T formula (66.6%). The 88.9% of the reports obtained a SE within ±1.00 D. Using A-115 for ultrasound biometry and A-115.7 for optical biometry and SRK/T formula, the emmetropia (±1.00 D) of SE, was able to get near 100% of reported cases over the pupil implantation. However, the emmetropia decreased to 80% when the enclavation is retropupilar using the same formula. The A-constant can vary from 116.7 to 117.5 for retropupilar enclavation. Conclusions: Using A-115 for ultrasound biometry and A-115.7 for optical biometry and SRK/T formula, ±1.00 D of SE, is able to get near 100% of cases. Nevertheless, ±1.00 D of SE decreased to 80% of the cases when the enclavation is retropupilar
Apples to apples A^2 – II. Cluster selection functions for next-generation surveys
We present the cluster selection function for three of the largest next-generation stage-IV surveys in the optical and infrared: Euclid-Optimistic, Euclid-Pessimistic and the Large Synoptic Survey Telescope (LSST). To simulate these surveys, we use the realistic mock catalogues introduced in the first paper of this series. We detected galaxy clusters using the Bayesian Cluster Finder in the mock catalogues. We then modelled and calibrated the total cluster stellar mass observable–theoretical mass (M^∗_(CL)—M_h) relation using a power-law model, including a possible redshift evolution term. We find a moderate scatter of σM^∗_(CL)|M_h) of 0.124, 0.135 and 0.136 dex for Euclid-Optimistic, Euclid-Pessimistic and LSST, respectively, comparable to other work over more limited ranges of redshift. Moreover, the three data sets are consistent with negligible evolution with redshift, in agreement with observational and simulation results in the literature. We find that Euclid-Optimistic will be able to detect clusters with >80 per cent completeness and purity down to 8 × 10^(13) h^(−1) M_⊙ up to z < 1. At higher redshifts, the same completeness and purity are obtained with the larger mass threshold of 2 × 10^(14) h^(−1) M_⊙ up to z = 2. The Euclid-Pessimistic selection function has a similar shape with ∼10 per cent higher mass limit. LSST shows ∼5 per cent higher mass limit than Euclid-Optimistic up to z < 0.7 and increases afterwards, reaching a value of 2 × 10^(14) h^(−1) M_⊙ at z = 1.4. Similar selection functions with only 80 per cent completeness threshold have also been computed. The complementarity of these results with selection functions for surveys in other bands is discussed
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