Reduced precipitation can induce ecosystem regime shifts in lakes by increasing internal nutrient recycling.

Eutrophication is a main threat to continental aquatic ecosystems. Prevention and amelioration actions have been taken under the assumption of a stable climate, which needs reconsideration. Here, we show that reduced precipitation can bring a lake ecosystem to a more productive regime even with a decline in nutrient external load. By analyzing time series of several decades in the largest lake of the Iberian Peninsula, we found autocorrelated changes in the variance of state variables (i.e., chlorophyll and oxygen) indicative of a transient situation towards a new ecosystem regime. Indeed, exceptional planktonic diatom blooms have occurred during the last few years, and the sediment record shows a shift in phytoplankton composition and an increase in nutrient retention. Reduced precipitation almost doubled the water residence time in the lake, enhancing the relevance of internal processes. This study demonstrates that ecological quality targets for aquatic ecosystems must be tailored to the changing climatic conditions for appropriate stewardship.

Co-Development of a Web Application (COVID-19 Social Site) for Long-Term Care Workers ("Something for Us"): User-Centered Design and Participatory Research Study.

BACKGROUND: Improving confidence in and uptake of COVID-19 vaccines and boosters among long-term care workers (LTCWs) is a crucial public health goal, given their role in the care of elderly people and people at risk. While difficult to reach with workplace communication interventions, most LTCWs regularly use social media and smartphones. Various social media interventions have improved attitudes and uptake for other vaccines and hold promise for the LTCW population. OBJECTIVE: We aimed to develop a curated social web application (interactive website) to increase COVID-19 vaccine confidence (a 3-arm randomized trial is underway). METHODS: Following user-centric design and participatory research approaches, we undertook the following 3 steps: (1) content identification, (2) platform development, and (3) community building. A LTCW and stakeholder advisory group provided iterative input. For content identification (step 1), we identified topics of concern about COVID-19 vaccines via desktop research (published literature, public opinion polls, and social media monitoring), refined by interviewing and polling LTCWs. We also conducted a national online panel survey. We curated and fact-checked posts from popular social media platforms that addressed the identified concerns. During platform development (step 2), we solicited preferences for design and functionality via interviews and user experience testing with LTCWs. We also identified best practices for online community building (step 3). RESULTS: In the interviews (n=9), we identified 3 themes: (1) LTCWs are proud of their work but feel undervalued; (2) LTCWs have varying levels of trust in COVID-19-related information; and (3) LTCWs would welcome a curated COVID-19 resource that is easy to understand and use-"something for us". Through desktop research, LTCW interviews, and our national online panel survey (n=592) we found that participants are interested in information about COVID-19 in general, vaccine benefits, vaccine risks, and vaccine development. Content identification resulted in 434 posts addressing these topic areas, with 209 uploaded to the final web application. Our LTCW poll (n=8) revealed preferences for personal stories and video content. The platform we developed is an accessible WordPress-based social media web application, refined through formal (n=3) and informal user experience testing. Users can sort posts by topic or subtopic and react to or comment on posts. To build an online community, we recruited 3 LTCW "community ambassadors" and instructed them to encourage discussion, acknowledge concerns, and offer factual information on COVID-19 vaccines. We also set "community standards" for the web application. CONCLUSIONS: An iterative, user-centric, participatory approach led to the launch of an accessible social media web application with curated content for COVID-19 vaccines targeting LTCWs in the United States. Through our trial, we will determine if this approach successfully improves vaccine confidence. If so, a similar social media resource could be used to develop curated social media interventions in other populations and with other public health goals.

Tumor de células granulares del esófago: reporte de un caso / Esophageal granular cell tumor: Case report

Introducción: el tumor de células granulares del esófago (TCG) es una neoplasia rara y su diagnóstico preciso se basa en el examen histopatológico. Con el incremento de la endoscopia como medida de tamizaje se ha visto un leve aumento en la incidencia, por lo que debe tenerse en cuenta como diagnóstico diferencial en el momento de abordar una lesión subepitelial. Metodología: presentación de un caso clínico con TCG cuya endoscopia de vías digestivas altas (EVDA) muestra una lesión subepitelial en el tercio distal del esófago, y que debido a las características histopatológicas, clínicas y ecosonográficas se decide seguimiento y manejo expectante. Conclusiones: es importante el conocimiento de las características, comportamientos y estrategias de manejo del TCG, puesmuchos son asintomáticos y estables en el seguimiento, por lo que no necesitan tratamientos agresivos. Por el riesgo de malignidad, es importante su control riguroso.

Introduction: Esophageal granular cell tumors (GCTs) are rare. Their precise diagnosis is based on histopathological examination of the specimen. However, owing to the use of endoscopy as a screening tool the incidence of these lesions has presently mildly increased and must be considered as a differential diagnosis of subepithelial lesions. Methodology: A case is presented of a GCT as a subepithelial lesion in the distal part of the esophagus found by esophagogastroduodenoscopy (EGD). Conservative management and follow-up was decided due to the histopathological, clinical and ultrasound features of the lesion. Conclusions: Knowledge regarding GCTs´i characteristics, behavior and management is important for many are asymptomatic and remain clinically stable during follow-up, requiring no aggressive treatment. A rigorous follow-up is recommended due to its malignant potential.

Methylation of DAPK and THBS1 genes in esophageal gastric-type columnar metaplasia.

AIM: To explore methylation of DAPK, THBS1, CDH-1, and p14 genes, and Helicobacter pylori (H. pylori) status in individuals harboring esophageal columnar metaplasia. METHODS: Distal esophageal mucosal samples obtained by endoscopy and histologically diagnosed as gastric-type (non-specialized) columnar metaplasia, were studied thoroughly. DNA was extracted from paraffin blocks, and methylation status of death-associated protein kinase (DAPK), thrombospondin-1 (THBS1), cadherin-1 (CDH1), and p14 genes, was examined using a methyl-sensitive polymerase chain reaction (MS-PCR) and sodium bisulfite modification protocol. H. pylori cagA status was determined by PCR. RESULTS: In total, 68 subjects (33 females and 35 males), with a mean age of 52 years, were included. H. pylori cagA positive was present in the esophageal gastric-type metaplastic mucosa of 18 individuals. DAPK, THSB1, CDH1, and p14 gene promoters were methylated by MS-PCR in 40 (58.8%), 33 (48.5%), 46 (67.6%), and 23 (33.8%) cases of the 68 esophageal samples. H. pylori status was associated with methylation of DAPK (P = 0.003) and THBS1 (P = 0.019). CONCLUSION: DNA methylation occurs in cases of gastric-type (non-specialized) columnar metaplasia of the esophagus, and this modification is associated with H. pylori cagA positive infection.

A flexible and inexpensive high-performance auditory evoked response recording system appropriate for research purposes.

Recording auditory evoked responses (AER) is done not only in hospitals and clinics worldwide to detect hearing impairments and estimate hearing thresholds, but also in research centers to understand and model the mechanisms involved in the process of hearing. This paper describes a high-performance, flexible, and inexpensive AER recording system. A full description of the hardware and software modules that compose the AER recording system is provided. The performance of this system was evaluated by conducting five experiments with both real and artificially synthesized auditory brainstem response and middle latency response signals at different intensity levels and stimulation rates. The results indicate that the flexibility of the described system is appropriate to record AER signals under several recording conditions. The AER recording system described in this article is a flexible and inexpensive high-performance AER recording system. This recording system also incorporates a platform through which users are allowed to implement advanced signal processing methods. Moreover, its manufacturing cost is significantly lower than that of other commercially available alternatives. These advantages may prove useful in many research applications in audiology.

Automatic quality assessment and peak identification of auditory brainstem responses with fitted parametric peaks.

The recording of the auditory brainstem response (ABR) is used worldwide for hearing screening purposes. In this process, a precise estimation of the most relevant components is essential for an accurate interpretation of these signals. This evaluation is usually carried out subjectively by an audiologist. However, the use of automatic methods for this purpose is being encouraged nowadays in order to reduce human evaluation biases and ensure uniformity among test conditions, patients, and screening personnel. This article describes a new method that performs automatic quality assessment and identification of the peaks, the fitted parametric peaks (FPP). This method is based on the use of synthesized peaks that are adjusted to the ABR response. The FPP is validated, on one hand, by an analysis of amplitudes and latencies measured manually by an audiologist and automatically by the FPP method in ABR signals recorded at different stimulation rates; and on the other hand, contrasting the performance of the FPP method with the automatic evaluation techniques based on the correlation coefficient, FSP, and cross correlation with a predefined template waveform by comparing the automatic evaluations of the quality of these methods with subjective evaluations provided by five experienced evaluators on a set of ABR signals of different quality. The results of this study suggest (a) that the FPP method can be used to provide an accurate parameterization of the peaks in terms of amplitude, latency, and width, and (b) that the FPP remains as the method that best approaches the averaged subjective quality evaluation, as well as provides the best results in terms of sensitivity and specificity in ABR signals validation. The significance of these findings and the clinical value of the FPP method are highlighted on this paper.

A study of adaptation mechanisms based on ABR recorded at high stimulation rate.

OBJECTIVE: This paper analyzes the fast and slow mechanisms of adaptation through a study of latencies and amplitudes on ABR recorded at high stimulation rates using the randomized stimulation and averaging (RSA) technique. METHODS: The RSA technique allows a separate processing of auditory responses, and is used, in this study, to categorize responses according to the interstimulus interval (ISI) of their preceding stimulus. The fast and slow mechanisms of adaptation are analyzed by the separated responses methodology, whose underlying principles and mathematical basis are described in detail. RESULTS: The morphology of the ABR is influenced by both fast and slow mechanisms of adaptation. These results are consistent with previous animal studies based on spike rate. CONCLUSIONS: Both fast and slow mechanisms of adaptation are present in all subjects. In addition, the distribution of the jitter and the sequencing of the stimuli may be critical parameters when obtaining reliable ABRs. SIGNIFICANCE: The separated responses methodology enables for the first time the analysis of the fast and slow mechanisms of adaptation in ABR obtained at stimulation rates greater than 100 Hz. The non-invasive nature of this methodology is appropriate for its use in humans.

Regioselective synthesis of 1,2-dihydroquinolines by a solvent-free MgBr2-catalyzed multicomponent reaction.

A highly efficient and regioselective synthesis of 1,2-dihydroquinolines via a multicomponent reaction between an aniline and two ketones is described. This reaction was catalyzed by magnesium bromide and carried out under solvent-free conditions. When the reaction was performed by using 3-substituted anilines and nonsymmetrically substituted ketones, principally a single product was found among the four expected regioisomers. A variety of anilines and ketones, including cyclic ketones, were evaluated providing a series of 1,2-dihydroquinolines with diverse substitution patterns. A study of the mechanism is discussed. There is evidence of the in situ formation of the imine as a result of the reaction between the aniline and one of the ketones, before annulation to the heterocyclic ring.

Analysis of electrical thresholds and maximum comfortable levels in cochlear implant patients.

OBJECTIVE: It is well known that a proper fitting of the cochlear implant processor is relevant to provide good quality in speech perception. The aim of this study is to extract statistical information to be applied for fitting the processor. METHODS: This study is based on the programming maps of 121 patients, aged from 18 months to 68 years at the moment of implantation. All subjects were implanted with the COMBI 40+ cochlear implant at San Cecilio University Hospital, Granada (Spain). The patients were classified into groups based on their age at implantation: younger than 5 years, between 5 and 16 years, and older than 16 years. The patients in each age-based group were divided into two subgroups, considering whether they had recent hearing experience or not. A special group including patients affected by severe damages in the cochlea was also defined. RESULTS: Relationships between the programming parameters and factors like the age at implantation, the hearing experience and the presence of severe cochlear damage were found. The THR levels for patients younger than 5 years were significantly lower than those for patients implanted between 5 and 16 years, and this group presented significantly lower THR levels than adults. The MCL levels were not significantly influenced by the age at implantation. A significant increment was observed for both, MCL and THR levels, when patients were affected by severe cochlear damage. A significant increment in the THR levels were observed for patients with no recent hearing experience, while no significant differences were found for MCL levels. This study also analyzes the distribution along the cochlea of the stimulation levels. In the case of patients not affected by severe cochlear damage, the most basal electrodes presented a significant increment in the stimulation levels with respect to the rest of electrodes. CONCLUSION: This work provides information of great value for programming the speech processors, particularly when the subjective responses of the patients are not sufficient. The application in our ENT Service has reduced substantially the average time needed to obtain an acceptable fitting of the processor, especially in children. Our study also shows that electrical thresholds are a good indicator of the functionality of the auditory nerve. The analysis of this parameter highlights the importance of an early intervention as well as a deep insertion of the electrode carrier in order to obtain the maximum functionality from the cochlear implant.

Long-term evolution of the electrical stimulation levels for cochlear implant patients.

OBJECTIVES: The stimulation levels programmed in cochlear implant systems are affected by an evolution since the first switch-on of the processor. This study was designed to evaluate the changes in stimulation levels over time and the relationship between post-implantation physiological changes and with the hearing experience provided by the continuous use of the cochlear implant. METHODS: Sixty-two patients, ranging in age from 4 to 68 years at the moment of implantation participated in this study. All subjects were implanted with the 12 channels COMBI 40+ cochlear implant at San Cecilio University Hospital, Granada, Spain. Hearing loss etiology and progression characteristics varied across subjects. RESULTS: The analyzed programming maps show that the stimulation levels suffer a fast evolution during the first weeks after the first switch-on of the processor. Then, the evolution becomes slower and the programming parameters tend to be stable at about 6 months after the first switch-on. The evolution of the stimulation levels implies an increment of the electrical dynamic range, which is increased from 15.4 to 20.7 dB and improves the intensity resolution. A significant increment of the sensitivity to acoustic stimuli is also observed. For some patients, we have also observed transitory changes in the electrode impedances associated to secretory otitis media, which cause important changes in the programming maps. CONCLUSION: We have studied the long-term evolution of the stimulation levels in cochlear implant patients. Our results show the importance of systematic measurements of the electrode impedances before the revision of the programming map. This report also highlights that the evolution of the programming maps is an important factor to be considered in order to determine an adequate calendar fitting of the cochlear implant processor.

Recording of auditory brainstem response at high stimulation rates using randomized stimulation and averaging.

The recording of auditory brainstem response (ABR) at high stimulation rates is of great interest in audiology. It allows a more accurate diagnosis of certain pathologies at an early stage and the study of different mechanisms of adaptation. This paper proposes a methodology, which we will refer to as randomized stimulation and averaging (RSA) that allows the recording of ABR at high stimulation rates using jittered stimuli. The proposed method has been compared with quasi-periodic sequence deconvolution (QSD) and conventional (CONV) stimulation methodologies. Experimental results show that RSA provides a quality in ABR recordings similar to that of QSD and CONV. Compared with CONV, RSA presents the advantage of being able to record ABR at rates higher than 100 Hz. Compared with QSD, the formulation of RSA is simpler and allows more flexibility on the design of the pseudorandom sequence. The feasibility of the RSA methodology is validated by an analysis of the morphology, amplitudes, and latencies of the most important waves in ABR recorded at high stimulation rates from eight normal hearing subjects.

Evaluación del tratamiento superovulatorio con extracto de hipófisis equina en yeguas criollas / Evaluation of superovulatory treatment with extract of equine hypophysis in creole mares

Se evaluó la respuesta superovulatoria en yeguas criollas a las cuales se aplicó extracto de hipófifis equina (EHE)en dos diferentes dosis, comparada con FSH de origen porcino (Folltropin V). Se tomaron 20 yeguas criollas Colombianas cíclicas con edades entre 2 y 8 años (5,3 años en promedio) las cuales fueron seleccionadas y asignadas al azar en 4 grupos así: Grupo 1 También llamado grupo control (T1): se les aplicó 5cc suero fisiológico IM (a.m., p.m.); grupo 2 (T2): 6,25mg Foltropin-v (FSH-P) IM (a.m., p.m.); Grupo 3 (T3): 8,3mg EHE IM (a.m., p.m.); Grupo 4 (T4): 12,5mg EHE IM (a.m., p.m.). Los tratamientos se iniciaron 7 días después de haber dectado una ovulación mediante ultrasonografía, el día 8 se aplicaron 12,5 mg PgF 2alfa vía IM. El tratamiento con EHE se suspendió cuando la mayoría de los folículos alcanzaron un tamaño > 35mm, momento en el cual se aplicaron 2500 UI de hCG vía IV, seguida de inseminación artificial. Entre el día 7 u 8 se realizaron las colectas de embriones mediante lavado uterino de circuito cerrado. Los datos se analizaron mediante un análisis de varianza por una vía (ANOVA), determinando el promedio de crecimiento folicular entre el día del inicio del tratamiento y la ovulación, el número de fóliculos preovulatorios con un tamaño > 35mm, el número de días de tratamiento y la cantidad de embriones colectados en cada grupo. Se realizó una prueba de rango o comparción múltiple de Duncan para observar las diferencias entre grupos y se determinó por análisis de relación el estado y la calidad de los embriones en cada tratamiento para determinar la viabilidad. Los resultados obtenidos demostraron que en T4 se desarrolló un mayor número de folículos > a 35mm en comparación con los demás grupos (P<0.005) en 7,4 días de tratamiento, mayor rata de crecimiento folicular (3.01 mm/día), mayor número de ovulaciones por tratamiento (2.8) y mayor número de embriones colectados por yegua (1,6), siendo este (T4) el tratamiento de mejores resultados res.

Conduccion del caudal natural

En el presente trabajo se analizan dos tipos, de embalses relacionados con dos formas de utilidad: a) Embalses de compensación. b) Embalses para regulación de avenidas. En cuanto al priner punto se analiza a una presa de compensación desde dos puntos de vistas principales, finalidad del sistema y la concepción económica. El inciso b apunta la utilidad que dan este tipo de embalses es el regular los picos de crecida para la protección de los lugares habitados o cultivados, aguas abajo del embalse, tal que el agua almacenada durante las crecidas se deje pasar posteriormente como lo permitan las capacidades de los canales. El proyecto plantea los puhtos para el estudio: 1. Generalidades. 2. Hidrograma de entrada. 3. Volúmene del almacenamiento. 4. Ecuaciones de descarga. 5. Amortiguamiento de la onda de crecida. 6. Canal de conducción. 7. Investigación del ambalse de forma triangular. 8. Investigación del volúmeen de almacenamiento elipdoidal. 9. Ejemplo práctico - evaluación del ambalse natural. 10. Análisis de costos. 11. Evaluación de los parámetros representativos. 12. Conclusiones