Large-scale seasonal forecasts of river discharge by coupling local and global datasets with a stacked neural network: Case for the Loire River system.

Accurate prediction of river discharge is critical for a wide range of sectors, from human activities to environmental hazard management, especially in the face of increasing demand for water resources and climate change. To address this need, a multivariate model that incorporates both local and global data sources, including river and piezometer gauges, sea level, and climate parameters. By employing phase shift analysis, the model optimizes correlations between the target discharge and 12 parameters related to hydrologic and climatic systems, all sampled daily. In addition, a stacked LSTM - a more complex neural network architecture - is used to improve information extraction ability. Exploring river dynamics in the Loire-Bretagne basin and its surroundings, the investigation delves into predictions in daily time steps for one, three, and six months ahead. The resulting forecast features high accuracy and efficiency in predicting river discharge fluctuations, showcasing superior performance in forecasting drought periods over flood peaks. A detailed examination on data used highlights the significance of both local and global datasets in predicting river discharge, where the former dictates short-term predictions, while the latter drives long-range forecasts. Seasonally extended forecasting confirms a strong connection between the forecast leading time and the shift in data correlation, with lower correlation at a lag of 3 months due to seasonal changes affecting forecast quality, compensated by a higher correlation at a longer lag of 6 months. Such mutual effect in this multi-time-step forecasting improves the predictive quality of a six-month horizon, thus encourages progress in long-term prediction to a seasonal scale. The research establishes a practical foundation for effectively utilizing big data to leverage long-term forecasting of environmental dynamics.

Long-run forecasting surface and groundwater dynamics from intermittent observation data: An evaluation for 50 years.

The accurate prediction of water dynamics is critical for operational water resource management. In this study, we propose a novel approach to perform long-term forecasts of daily water dynamics, including river levels, river discharges, and groundwater levels, with a lead time of 7-30 days. The approach is based on the state-of-the-art neural network, bidirectional long short-term memory (BiLSTM), to enhance the accuracy and consistency of dynamic predictions. The operation of this forecasting system relies on an in-situ database observed for over 50 years with records gauging in 19 rivers, the karst aquifer, the English Channel, and the meteorological network in Normandy, France. To address the problem of missing measurements and gauge installations over time, we developed an adaptive scheme in which the neural network is regularly adjusted and re-trained in response to changing inputs during a long operation. Advances in BiLSTM with extensive learning past-to-future and future-to-past further help to avoid time-lag calibration that simplifies data processing. The proposed approach provides high accuracy and consistent prediction for the three water dynamics within a similar accuracy range as an on-site observation, with approximately 3 % error in the measurement range for the 7 day-ahead predictions and 6 % error for the 30 d-ahead predictions. The system also effectively fills the gap in actual measurements and detects anomalies at gauges that can last for years. Working with multiple dynamics not only proves that the data-driven model is a unified approach but also reveals the impact of the physical background of the dynamics on the performance of their predictions. Groundwater undergoes a slow filtration process following a low-frequency fluctuation, favoring long-term prediction, which differs from other higher-frequency river dynamics. The physical nature drives the predictive performance even when using a data-driven model.

Application of level-set method for deposition in three-dimensional reconstructed porous media.

Three-dimensional (3D) porous structures which are usually discretized by voxels can also be discretized by the level-set method (LSM) and flow, reactive transport, and structure evolution can be modeled. The determination of the solid-liquid interface is detailed as well as the discretization of the governing equations. Comparisons between a one-dimensional analytical solution and LSM are conducted for validation. Deposition in 3D reconstructed media is studied under various flow and reaction conditions. The evolution of the structure is explored locally by means of the pore geometry and globally by means of the permeability and the porosity. The difference between the voxel method and LSM is discussed during the investigations.

The complete nucleotide sequence of two distinct geminiviruses infecting cucurbits in Vietnam.

We have characterised two distinct geminiviruses that infect cucurbit cultivars in Vietnam. The genomes of both viruses consisted of two circular ssDNA components (DNA-A and DNA-B), with a genome arrangement and coding sequence typical of viruses in the Begomovirus genus in the family Geminiviridae. The sequence of DNA-A of one of the viruses was approximately 97% similar to Squash leaf curl virus-China (SLCV-Ch), for which a DNA-B has yet to be identified. We have named this virus Squash leaf curl virus-Vietnam (SLCV-Vn). The intergenic region of the SLCV-Vn DNA-B contained a 40 nt deletion between the putative AC1 TATA box and the stem loop. A second virus isolated from loofa in southern Vietnam was only 80% similar to SLCV-Vn over the complete DNA-A sequence, however the nucleotide sequence in the coat protein coding regions was 95% similar. We have named this virus Loofa yellow mosaic virus-Vietnam (LYMV-Vn). Other regions of the SLCV-Vn and LYMV-Vn genomes differed markedly, suggesting the coat protein coding region was recombinant. The DNA-B of both viruses were only 60% similar over the complete nucleotide sequence, although the encoded amino acid sequence of the BC1 gene was 90% identical.

Characterisation of Rep-encoding components associated with banana bunchy top nanovirus in Vietnam.

We have analysed the sequence variability of the banana bunchy top nanovirus (BBTV) DNA-1 sequence from 17 isolates collected throughout Vietnam, and showed that the level of DNA-1 sequence variation within Vietnam was approximately double that previously reported for Asian BBTV isolates. Furthermore, the sequences separated into two geographical subgroups that generally correlated to the northern or southern regions of Vietnam. We have also characterised an additional putative Rep-encoding component associated with some BBTV isolates from Vietnam. This component, which we have named BBTV-S3, shared 47%, 69%, 56% and 65% nucleotide sequence identity with the previously reported Rep-encoding components BBTV DNA-1, S1, S2 and Y1 respectively.

Prevalence of chronic otitis media in a randomly selected population from two communes in southern Vietnam.

The prevalence of chronic otitis media was studied in an urban and a rural community in southern Vietnam in 1995. A total of 3,300 children, aged from 6 months to 10 years, were selected randomly by taking every third child on the vaccination list. In this cross-sectional study, 453 ears were found to have chronic otitis media or sequelae otitidis, giving an overall prevalence of 6.86%. A total of 140 ears had perforations. Various attic changes were found in 73 ears and other chronic tympanic membrane changes, such as atrophy, tympanosclerosis and adhesions, in 219 ears. Cholesteatoma was seen in two ears.

Point prevalence of secretory otitis media in children in southern Vietnam.

Few reliable data exist on the prevalence of secretory otitis media (SOM) in the Third World. A large epidemiologic cross-sectional study was undertaken in two communes in southern Vietnam to study an urban and a rural community during two different climatic conditions: the dry and rainy seasons. The participants included 3,300 children (6,598 ears) ages 6 months to 10 years. Otolaryngological and medical histories were obtained, and an otolaryngological examination was carried out on 1,669 children in April 1995 (the dry season) and on 1,631 children in December 1995 (the rainy season). Tympanograms were obtained (n = 6,055), 429 of which were type B curves. The overall prevalence of SOM was 7.1%, the highest incidence was at the age of 2 years (with a prevalence of 22%), and there was a significantly higher prevalence of SOM during the rainy season than during the dry season. No significant difference in incidence was found in the urban district as compared to the rural district.

Poverty and mortality among the elderly: measurement of performance in 33 countries 1960-92.

This paper analyses the effect of income and education on life expectancy and mortality rates among the elderly in 33 countries for the period 1960-92 and assesses how that relationship has changed over time as a result of technical progress. Our outcome variables are life expectancy at age 60 and the probability of dying between age 60 and age 80 for both males and females. The data are from vital-registration based life tables published by national statistical offices for several years during this period. We estimate regressions with determinants that include GDP per capita (adjusted for purchasing power), education and time (as a proxy for technical progress). As the available measure of education failed to account for variation in life expectancy or mortality at age 60, our reported analyses focus on a simplified model with only income and time as predictors. The results indicate that, controlling for income, mortality rates among the elderly have declined considerably over the past three decades. We also find that poverty (as measured by low average income levels) explains some of the variation in both life expectancy at age 60 and mortality rates among the elderly across the countries in the sample. The explained amount of variation is more substantial for females than for males. While poverty does adversely affect mortality rates among the elderly (and the strength of this effect is estimated to be increasing over time), technical progress appears far more important in the period following 1960. Predicted female life expectancy (at age 60) in 1960 at the mean income level in 1960 was, for example 18.8 years; income growth to 1992 increased this by an estimated 0.7 years, whereas technical progress increased it by 2.0 years. We then use the estimated regression results to compare country performance on life expectancy of the elderly, controlling for levels of poverty (or income), and to assess how performance has varied over time. High performing countries, on female life expectancy at age 60, for the period around 1990, included Chile (1.0 years longer life expectancy), China (1.7 years longer), France (2.0 years longer), Japan (1.9 years longer), and Switzerland (1.3 years longer). Poorly performing countries included Denmark (1.1 years shorter life expectancy than predicted from income), Hungary (1.4 years shorter), Iceland (1.2 years shorter), Malaysia (1.6 years shorter), and Trinidad and Tobago (3.9 years shorter). Chile and Switzerland registered major improvements in relative performance over this period; Norway, Taiwan and the USA, in contrast showed major declines in performance between 1980 and the early 1990s.

The early postoperative pressure course in glaucoma patients following cataract surgery.

The intraocular pressure (IOP) course during the first 2 months after cataract surgery in patients with preexisting glaucoma was evaluated in 25 consecutive cases of extracapsular cataract extraction (ECCE) with posterior chamber intraocular lens (PC-IOL) implantation and in 25 cases of intracapsular cataract extraction (ICCE) without IOL implantation. Although the former group had a slightly more favorable postoperative IOP course, approximately half of each group had a pressure rise above 21 mm Hg on the first day postoperatively, and approximately 80% had an IOP rise during the first postoperative month. These findings support the position that all glaucoma patients require close monitoring of their IOPs immediately after both ECCE and ICCE, and that patients with moderate to advanced glaucomatous damage should probably have glaucoma surgery either before or in combination with their cataract operation.

Effect of irradiation on vascularization of corneas grafted onto chorioallantoic membranes.

Several studies have shown that total body irradiation decreases the angiogenic response to corneal cauterization. This inhibition could be due to alterations in angiogenic stimuli within injured corneas and/or to a decreased ability of irradiated animals to respond to such stimuli. To determine whether total body irradiation specifically affects angiogenic stimuli within injured corneal tissue, cauterized corneas from mice exposed to 900 rads of total body irradiation and from non-irradiated controls were grafted onto the chorioallantoic membranes (CAM) of chick embryos and their abilities to stimulate the ingrowth of healthy embryonic blood vessels were compared. Cauterized corneas incorporated into CAM mesenchymal tissue were invaded by blood vessels in 34.6% of the irradiated group and in 75% of the non-irradiated controls. This difference in the two groups was statistically significant (P less than 0.03). Total body irradiation significantly decreased the frequency of vascular invasion of cauterized corneal tissues by healthy CAM blood vessels. This finding suggests that total body irradiation can specifically affect the stimulus for angiogenesis within cauterized corneas.

An evaluation of methods to quantitate the chick chorioallantoic membrane assay in angiogenesis.

The vascular responses by chick chorioallantoic membranes (CAM) to more than 150 normal and chemically injured rat corneas grafted to shell-less chicken CAMs were evaluated independently by three observers in a masked fashion by in vivo stereomicroscopy, projections of colored transparencies, and by light microscopy of tissue sections of the grafts. The experience gained from this study is reviewed as a point of focus for the strengths and weaknesses of the CAM technique in the assay of potential angiogenic substances. Despite certain shortcomings, the CAM technique can provide useful information relevant to studies on angiogenesis, particularly when the subjective CAM method is supplemented by histological evaluation of grafted tissues.

Angiogenic activity in injured rat corneas as assayed on the chick chorioallantoic membrane.

The temporal appearance of an angiogenic effect in chemically cauterized rat corneas was determined by studying the responses that they induced in the vessels of the chick chorioallantoic membrane (CAM). Injured rat corneas were grafted to the CAM from 90 minutes to 7 days after cautery. As controls, uninjured rat corneas and corneas of healthy rats cauterized immediately after death were also grafted. The vascular responses to the grafts were graded in a masked fashion by stereoscopic biomicroscopy on a five-tiered scale, by evaluations of projected colored photographs on the same scale, and by histologic examination of the grafts. Separate coefficients of angiogenesis were determined for the stereoscopic and photographic evaluations. We detected significant differences between corneas of healthy rats that were uninjured or cauterized chemically immediately after death and those that were cauterized in the living rat. Uninjured corneas and corneas cauterized postmortem elicited a mild vascular response in the CAM, as reflected by low coefficients of angiogenesis. Whereas blood vessels were not detected in corneas injured postmortem, some normal corneas vascularized but only after being on the CAM for at least 7 days. The coefficients of angiogenesis of corneas that were cauterized during life were significantly higher than those of both control groups prior to grafting after comparable times on the CAM. Corneas vascularized on the CAM included those that were cauterized as soon as 90 minutes prior to grafting. The strongest vascular responses, as reflected by coefficient of angiogenesis and the frequency of histologically confirmed nucleated avian erythrocytes within intracorneal blood vessels, were found with corneas that were grafted to the CAM 3 days after chemical cauterization. Corneas that vascularized on the CAM were associated with a prominent leukocytic infiltrate suggestively derived from the chick embryo. The results suggest that chemically cauterized rat corneas contain a chemoattractant for polymorphonuclear leukocytes within 90 minutes of injury and that such polymorphonuclear leukocytes or other components of the injured corneas possess the ability to stimulate angiogenesis on the CAM.