A reply to "Relevant factors in the eutrophication of the Uruguay River and the Río Negro".

A recent paper by Beretta-Blanco and Carrasco-Letelier (2021) claims that agricultural eutrophication is not one of the main causes for cyanobacterial blooms in rivers and artificial reservoirs. By combining rivers of markedly different hydrological characteristics e.g., presence/absence and number of dams, river discharge and geological setting, the study speculates about the role of nutrients for modulating phytoplankton chlorophyll-a. Here, we identified serious flaws, from erratic and inaccurate data manipulation. The study did not define how erroneous original dataset values were treated, how the variables below the detection/quantification limit were numerically introduced, lack of mandatory variables for river studies such as flow and rainfall, arbitrary removal of pH > 7.5 values (which were not outliers), and finally how extreme values of other environmental variables were included. In addition, we identified conceptual and procedural mistakes such as biased construction/evaluation of model prediction capability. The study trained the model using pooled data from a short restricted lotic section of the (large) Uruguay River and from both lotic and reservoir domains of the Negro River, but then tested predictability within the (small) Cuareim River. Besides these methodological considerations, the article shows misinterpretations of the statistical correlation of cause and effect neglecting basic limnological knowledge of the ecology of harmful algal blooms (HABs) and international research on land use effects on freshwater quality. The argument that pH is a predictor variable for HABs neglects overwhelming basic paradigms of carbon fluxes and change in pH because of primary productivity. As a result, the article introduces the notion that HABs formation are not related to agricultural land use and water residence time and generate a great risk for the management of surface waterbodies. This reply also emphasizes the need for good practices of open data management, especially for public databases in view of external reproducibility.

Asc-Seurat: analytical single-cell Seurat-based web application.

BACKGROUND: Single-cell RNA sequencing (scRNA-seq) has revolutionized the study of transcriptomes, arising as a powerful tool for discovering and characterizing cell types and their developmental trajectories. However, scRNA-seq analysis is complex, requiring a continuous, iterative process to refine the data and uncover relevant biological information. A diversity of tools has been developed to address the multiple aspects of scRNA-seq data analysis. However, an easy-to-use web application capable of conducting all critical steps of scRNA-seq data analysis is still lacking. We present Asc-Seurat, a feature-rich workbench, providing an user-friendly and easy-to-install web application encapsulating tools for an all-encompassing and fluid scRNA-seq data analysis. Asc-Seurat implements functions from the Seurat package for quality control, clustering, and genes differential expression. In addition, Asc-Seurat provides a pseudotime module containing dozens of models for the trajectory inference and a functional annotation module that allows recovering gene annotation and detecting gene ontology enriched terms. We showcase Asc-Seurat's capabilities by analyzing a peripheral blood mononuclear cell dataset. CONCLUSIONS: Asc-Seurat is a comprehensive workbench providing an accessible graphical interface for scRNA-seq analysis by biologists. Asc-Seurat significantly reduces the time and effort required to analyze and interpret the information in scRNA-seq datasets.

Advanced interatrial block as a substrate of supraventricular tachyarrhythmias: a well recognized syndrome.

Interatrial blocks (IABs) are well described and accepted in the scientific community. In the last four decades major discoveries were made including its physiopathology, ECG presentation, classification and association with atrial tachyarrhythmias (advanced IAB). This article will briefly review the state of the art on the understanding of advanced IAB as an electrical substrate for atrial tachyarrhythmias as well as the future directions.

Competition drives clumpy species coexistence in estuarine phytoplankton.

Understanding the mechanisms that maintain biodiversity is a fundamental problem in ecology. Competition is thought to reduce diversity, but hundreds of microbial aquatic primary producers species coexist and compete for a few essential resources (e.g., nutrients and light). Here, we show that resource competition is a plausible mechanism for explaining clumpy distribution on individual species volume (a proxy for the niche) of estuarine phytoplankton communities ranging from North America to South America and Europe, supporting the Emergent Neutrality hypothesis. Furthermore, such a clumpy distribution was also observed throughout the Holocene in diatoms from a sediment core. A Lotka-Volterra competition model predicted position in the niche axis and functional affiliation of dominant species within and among clumps. Results support the coexistence of functionally equivalent species in ecosystems and indicate that resource competition may be a key process to shape the size structure of estuarine phytoplankton, which in turn drives ecosystem functioning.

Classification of samples into two or more ordered populations with application to a cancer trial.

In many applications, especially in cancer treatment and diagnosis, investigators are interested in classifying patients into various diagnosis groups on the basis of molecular data such as gene expression or proteomic data. Often, some of the diagnosis groups are known to be related to higher or lower values of some of the predictors. The standard methods of classifying patients into various groups do not take into account the underlying order. This could potentially result in high misclassification rates, especially when the number of groups is larger than two. In this article, we develop classification procedures that exploit the underlying order among the mean values of the predictor variables and the diagnostic groups by using ideas from order-restricted inference. We generalize the existing methodology on discrimination under restrictions and provide empirical evidence to demonstrate that the proposed methodology improves over the existing unrestricted methodology. The proposed methodology is applied to a bladder cancer data set where the researchers are interested in classifying patients into various groups.

Internal symmetry in the multifractal spectrum of fully developed turbulence.

In the context of multifractal theory and She-Lévêque's model describing the statistics of intermittency in fully developed turbulence, we show that the multifractal dimensions can be simply written F(alpha)=1+alpha*-alpha*ln(alpha*/2) with alpha*=(2 beta-1-alpha)/ln beta=2 beta(p), where p is the order associated to the moment (with p> or =0) based on the rate of energy dissipation epsilon(r) and beta=[(1+3/the square root of 8)(1/3)+(1-3/the square root of 8)(1/3](3) approximately equal to 0.68). Introducing the fractal dimensions Delta(p)=F(alpha)+alpha*ln(alpha*/2), this leads to the recursive relation beta=(Delta(p+1)-Delta(infinity))/(Delta(p)-Delta(infinity)) with Delta(infinity)=1. This suggests the existence of an internal symmetry in the multifractal spectrum of fully developed turbulence, which reduces considerably the number of parameters necessary to characterize intermittency statistics.

[Audit of a hospital internal communication]. / Auditoría de comunicación interna de un hospital.

OBJECTIVES: To know the current status of internal communication as perceived by the professional staff (physicians, nurses), middle-level managers, and executive team, and possible future strategies for improving internal communication as perceived by the professional staff. METHODS: The study approach consisted of qualitative methods such as focal groups and semistructured interviews. The study area was a regional hospital. Study subjects included the attending staff (physicians and nurses), middle-level managers (supervisors and department heads), and executives (area heads, nursing director, and medical director). From the base staff, 20 nurses and 18 physicians were chosen for four focal groups. Among the middle-level managers, 2 supervisors and 4 department heads were chosen randomly. Three executive officers were interviewed. RESULTS: The weak and strong points of the hospital's internal communication were shown. Nursing and medical staff noted as an important weak point the fact that they did not feel that directors were listening to them. The professional staff noted as a weak point that they do not receive congratulations or positive reinforcement of any type. With respect of downward information channels, the staff indicated that they do not work because their first information received is always in the form of rumors. The physicians evaluated as a strong point that information always passes through the department head. They evaluated as a strong point good intradepartmental relations. The nurses evaluated as a weak point the obstacles to communication that they encounter. They propose future improvements such as developing itinerant communication, electing directors, using informal channels, recognizing staff achievements, and developing a communication plan. CONCLUSIONS: Internal communication should be understood by executives as part of basic professional management strategy. Given the results of this audit, it will be important to establish an internal communication plan to advance hospital objectives in every sense, at every level and for all professional categories.

Acute ethanol administration reduces the cognitive deficits associated with traumatic brain injury in rats.

The present study was designed to determine whether a low dose of acute ethanol administration could attenuate cognitive deficits associated with traumatic brain injury. Adult male rats received oral administration of ethanol or drinking water 2 h prior to surgery to produce a blood ethanol concentration of 100 mg% and then received bilateral contusion injuries of the medial prefrontal cortex. Seven days after surgery, the rats began 10 days of testing for acquisition of spatial localization in the Morris water maze where they were required to find a hidden platform to escape from the water. The results indicate that the rats given ethanol at the time of injury later spent significantly less time searching for the hidden platform than their water-treated counterparts. On a memory probe test given on the final day of testing, in which the platform was removed from the pool, rats given the ethanol spent more time in the area where the platform had been located indicating that they learned its location better than the lesion/water controls. In addition, acute ethanol treatment reduced some of the histopathology that typically occurs following severe contusion of the medial frontal cortex but did not attenuate post-traumatic formation of edema. These results indicate that acute ethanol intoxication can reduce the severity of cognitive impairments caused by contusive traumatic brain injury and support the contention that there is a dose-response relationship of acute ethanol intoxication in the setting of traumatic brain injury.

Etude analytique des facteurs de risque au cours de la grossesse dans cinq centres urbains de Conakry

Dans une enquete clinique; les auteurs etudient les facteurs de risque les plus frequemment rencontres au cours de la grossesse dans cinq centres de sante urbains de Conakry. La conclusion est que la strategie de l'approche en fonction du risque devrait etre la methode de travail dans les centres de sante maternelle et infantile. Cela permettrait des references a temps et dans les bonnes conditions

Effect of amiodarone and propranolol on the functional properties of human thyroid follicles cultured in collagen gel.

Amiodarone and propranolol have been known to inhibit the peripheral conversion of thyroxine (T4) to 3,5,3'-triiodothyronine (T3) but their direct effect on the thyroid gland is not understood. We therefore investigated the action of the two drugs on the functional properties of human thyroid follicles embedded in collagen gel. Amiodarone and propranolol induced a dose-dependent reduction or blocking of the follicular production of cyclic AMP (cAMP), thyroglobulin (Tg) and free triiodothyronine (FT3) under 200 microU/ml medium. Small drug doses and the drug solvents did not affect the follicular secretion. The inhibiting effect of amiodarone and propranolol on follicular production of cAMP, Tg and FT3 appears to result from several factors: (1) inhibition of thyroid 5'-deiodinase; (2) amiodarone high iodine content; (3) a quinidine-like effect of propranolol involving a membrane-stabilizing mechanism.

Functional properties of human thyroid follicles cultured within collagen gel.

Cultures of human thyroid follicles embedded in collagen gel were performed to investigate certain functional properties under bovine thyrotropin (TSH) stimulation. Follicles obtained from normal glands responded to increasing concentrations of TSH administered on day 4 in culture and for 3 days by increased amounts of cyclic AMP (cAMP), thyroglobulin (Tg) and triiodothyronine (T3) and by decreased levels of thyroxine (T4). Effect was maximal at 2000 microU/ml TSH (cAMP) or 200 microU/ml (Tg, T3, T4). When methimazole or propylthiouracil (PTU) were added, the T3 levels decreased. Follicle lumens contained a periodic acid-Schiff substance which was identified by immunoreaction as Tg. Thyroid follicles obtained from Graves' disease glands gave modified results with an earlier and intensified T3 response and no increase in Tg. These data show that (1) Tg and T3 are secretory products of functional follicles giving a cAMP-mediated response to TSH. (2) The detected T3 also derives from T4 5'-deiodination inhibited by PTU. (3) Intensified T3 response in Graves' follicles is probably due to enhanced conversion of T4 to T3.