Citología vaginal en cerdas: determinación de patrones celulares en relación con la fase del ciclo estral.

Reproductivamente, la cerda se clasifica como poliéstrica continua, con un ciclo estral de 21 días promedio, que se divide en una fase folicular (proestro y estro); y una fase luteal (metaestro y diestro). Durante este ciclo participan diferentes hormonas que inducen cambios comportamentales, anatómicos e histológicos en las cerdas. Estos últimos pueden observarse mediante el uso de citología vaginal exfoliativa2. El objetivo del trabajo fue determinar mediante citología vaginal exfoliativa los distintos tipos celulares presentes en cada estadio del ciclo estral de la cerda. El estudio se realizó en una granja de 2800 madres. Se seleccionaron 31 hembras al momento del destete. Se tomaron muestras para estudios citológicos. Durante la observación microscópica se identificaron y contaron células epiteliales vaginales (células parabasales, intermedias, superficiales y escamas) estableciendo el porcentaje promedio de cada tipo celular. Se compararon dos grupos celulares: grupo 1 (parabasales e intermedias) vs grupo 2 (superficiales y escamas) según Rodgers 19933. Se observó un descenso progresivo del grupo 1 desde el 1er día del proestro hacia el final del estro, a la inversa del grupo 2. En relación al metaestro, el % de ambos grupos fue similar. En el diestro temprano se observó un predominio de células del grupo 2, mientras que, en el diestro tardío, predominaron las células del grupo 1

Modified f(R) gravity from scalar-tensor theory and inhomogeneous EoS dark energy

The reconstruction of f(R)-gravity is showed by using an auxiliary scalar field in the context of cosmological evolution, this development provide a way of reconstruct the form of the function f (R) for a given evolution of the Hubble parameter. In analogy, f(R)-gravity may be expressed by a perfect fluid with an inhomogeneous equation of state that depends on the Hubble parameter and its derivatives. This mathematical equivalence that may confuse about the origin of the mechanism that produces the current acceleration, and possibly the whole evolution of the Hubble parameter, is shown here.Comment: 8 page

Progression of regional grey matter atrophy in multiple sclerosis

Grey matter atrophy is present from the earliest stages of multiple sclerosis, but its temporal ordering is poorly understood. We aimed to determine the sequence in which grey matter regions become atrophic in multiple sclerosis and its association with disability accumulation. In this longitudinal study, we included 1417 subjects: 253 with clinically isolated syndrome, 708 with relapsing-remitting multiple sclerosis, 128 with secondary-progressive multiple sclerosis, 125 with primary-progressive multiple sclerosis, and 203 healthy control subjects from seven European centres. Subjects underwent repeated MRI (total number of scans 3604); the mean follow-up for patients was 2.41 years (standard deviation = 1.97). Disability was scored using the Expanded Disability Status Scale. We calculated the volume of brain grey matter regions and brainstem using an unbiased within-subject template and used an established data-driven event-based model to determine the sequence of occurrence of atrophy and its uncertainty. We assigned each subject to a specific event-based model stage, based on the number of their atrophic regions. Linear mixed-effects models were used to explore associations between the rate of increase in event-based model stages, and T2 lesion load, disease-modifying treatments, comorbidity, disease duration and disability accumulation. The first regions to become atrophic in patients with clinically isolated syndrome and relapse-onset multiple sclerosis were the posterior cingulate cortex and precuneus, followed by the middle cingulate cortex, brainstem and thalamus. A similar sequence of atrophy was detected in primary-progressive multiple sclerosis with the involvement of the thalamus, cuneus, precuneus, and pallidum, followed by the brainstem and posterior cingulate cortex. The cerebellum, caudate and putamen showed early atrophy in relapse-onset multiple sclerosis and late atrophy in primary-progressive multiple sclerosis. Patients with secondary-progressive multiple sclerosis showed the highest event-based model stage (the highest number of atrophic regions, P < 0.001) at the study entry. All multiple sclerosis phenotypes, but clinically isolated syndrome, showed a faster rate of increase in the event-based model stage than healthy controls. T2 lesion load and disease duration in all patients were associated with increased event-based model stage, but no effects of disease-modifying treatments and comorbidity on event-based model stage were observed. The annualized rate of event-based model stage was associated with the disability accumulation in relapsing-remitting multiple sclerosis, independent of disease duration (P < 0.0001). The data-driven staging of atrophy progression in a large multiple sclerosis sample demonstrates that grey matter atrophy spreads to involve more regions over time. The sequence in which regions become atrophic is reasonably consistent across multiple sclerosis phenotypes. The spread of atrophy was associated with disease duration and with disability accumulation over time in relapsing-remitting multiple sclerosis

Techno-Economic Analysis of a 10 MWe Solar Thermal Power Plant Using Ammonia-Based Thermochemical Energy Transfer

The production of solar thermal power on a continuous, 24-h basis is possible by applying thermochemical energy storage. An international group of industrial and academic partners is studying such a base-load solar power plant concept, where the reversible thermo-catalytic ammonia reaction serves as the energy vector between supply and demand. Early results confirm the technical soundness of the concept using conventional technology, equipment and materials, and indicate also the potential for economic viability. A first-of-a-kind, solar-only demonstration power plant with a net capacity of 10 MWe would require a capital investment of the order of AUD 180 million and operate with a net solar-to-electric conversion efficiency of 18% and a capacity factor of 80%. This would result in levelised electricity costs of less than AUD 0.25 per kWh

Critical Appraisal of Artificial Intelligence-Enabled Imaging Tools Using the Levels of Evidence System.

Clinical adoption of an artificial intelligence-enabled imaging tool requires critical appraisal of its life cycle from development to implementation by using a systematic, standardized, and objective approach that can verify both its technical and clinical efficacy. Toward this concerted effort, the ASFNR/ASNR Artificial Intelligence Workshop Technology Working Group is proposing a hierarchal evaluation system based on the quality, type, and amount of scientific evidence that the artificial intelligence-enabled tool can demonstrate for each component of its life cycle. The current proposal is modeled after the levels of evidence in medicine, with the uppermost level of the hierarchy showing the strongest evidence for potential impact on patient care and health care outcomes. The intended goal of establishing an evidence-based evaluation system is to encourage transparency, foster an understanding of the creation of artificial intelligence tools and the artificial intelligence decision-making process, and to report the relevant data on the efficacy of artificial intelligence tools that are developed. The proposed system is an essential step in working toward a more formalized, clinically validated, and regulated framework for the safe and effective deployment of artificial intelligence imaging applications that will be used in clinical practice

Global Regulations for a Digital Economy: Between New and Old Challenges

© 2020 Durham University and John Wiley & Sons, Ltd Digital technologies are often described as posing unique challenges for public regulators worldwide. Their fast-pace and technical nature are viewed as being incompatible with the relatively slow and territorially bounded public regulatory processes. In this paper, we argue that not all digital technologies pose the same challenges for public regulators. We more precisely maintain that the digital technologies’ label can be quite misleading as it actually represents a wide variety of technical artifacts. Based on two dimensions, the level of centralization and (im)material nature, we provide a typology of digital technologies that importantly highlights how different technical artifacts affect differently local, national, regional and global distributions of power. While some empower transnational businesses, others can notably reinforce states’ power. By emphasizing this, our typology contributes to ongoing discussions about the global regulation of a digital economy and helps us identify the various challenges that it might present for public regulators globally. At the same time, it allows us to reinforce previous claims that these are importantly, not all new and that they often require us to solve traditional cooperation problems