Universidad Nacional de Entre Ríos

In this paper an algorithm based on the ensemble empirical mode decomposition (EEMD) is presented. The key idea on the EEMD relies on averaging the modes obtained by EMD applied to several realizations of Gaussian white noise added to the original signal. The resulting decomposition solves the EMD mode mixing problem, however it introduces new ones. In the method here proposed, a particular noise is added at each stage of the decomposition and a unique residue is computed to obtain each mode. The resulting decomposition is complete, with a numerically negligible error. Two examples are presented: a discrete Dirac delta function and an electrocardiogram signal. The results show that, compared with EEMD, the new method here presented also provides a better spectral separation of the modes and a lesser number of sifting iterations is needed, reducing the computational cost.

, water, and energy exchange between the biosphere and the atmosphere, and other meteorological and biological measurements, from 212 sites around the globe (over 1500 site-years, up to and including year 2014). These sites, independently managed and operated, voluntarily contributed their data to create global datasets. Data were quality controlled and processed using uniform methods, to improve consistency and intercomparability across sites. The dataset is already being used in a number of applications, including ecophysiology studies, remote sensing studies, and development of ecosystem and Earth system models. FLUXNET2015 includes derived-data products, such as gap-filled time series, ecosystem respiration and photosynthetic uptake estimates, estimation of uncertainties, and metadata about the measurements, presented for the first time in this paper. In addition, 206 of these sites are for the first time distributed under a Creative Commons (CC-BY 4.0) license. This paper details this enhanced dataset and the processing methods, now made available as open-source codes, making the dataset more accessible, transparent, and reproducible.

Artificial intelligence (AI) systems for computer-aided diagnosis and image-based screening are being adopted worldwide by medical institutions. In such a context, generating fair and unbiased classifiers becomes of paramount importance. The research community of medical image computing is making great efforts in developing more accurate algorithms to assist medical doctors in the difficult task of disease diagnosis. However, little attention is paid to the way databases are collected and how this may influence the performance of AI systems. Our study sheds light on the importance of gender balance in medical imaging datasets used to train AI systems for computer-assisted diagnosis. We provide empirical evidence supported by a large-scale study, based on three deep neural network architectures and two well-known publicly available X-ray image datasets used to diagnose various thoracic diseases under different gender imbalance conditions. We found a consistent decrease in performance for underrepresented genders when a minimum balance is not fulfilled. This raises the alarm for national agencies in charge of regulating and approving computer-assisted diagnosis systems, which should include explicit gender balance and diversity recommendations. We also establish an open problem for the academic medical image computing community which needs to be addressed by novel algorithms endowed with robustness to gender imbalance.

Human spatial behavior has been the focus of hundreds of previous research studies. However, the conclusions and generalizability of previous studies on interpersonal distance preferences were limited by some important methodological and sampling issues. The objective of the present study was to compare preferred interpersonal distances across the world and to overcome the problems observed in previous studies. We present an extensive analysis of interpersonal distances over a large data set ( N = 8,943 participants from 42 countries). We attempted to relate the preferred social, personal, and intimate distances observed in each country to a set of individual characteristics of the participants, and some attributes of their cultures. Our study indicates that individual characteristics (age and gender) influence interpersonal space preferences and that some variation in results can be explained by temperature in a given region. We also present objective values of preferred interpersonal distances in different regions, which might be used as a reference data point in future studies.

Abstract Vegetation changes, particularly those involving transitions between tree‐ and grass‐dominated covers, often modify evaporative water losses as a result of plant‐mediated shifts in moisture access and demand. Massive afforestation of native grasslands, particularly important in the Southern Hemisphere, may have strong yet poorly quantified effects on the hydrological cycle. We explored water use patterns in Eucalyptus grandis plantations and the native humid grasslands that they replace in Central Argentina. In order to uncover the interactive effects that land cover type, soil texture and climate variability may have on evaporative water losses and water use efficiency, we estimated daily evapotranspiration (ET) in 117 tree plantations and grasslands plots across a soil textural gradient (clay‐textured Vertisols to sandy‐textured Entisols) using radiometric information from seven Landsat scenes, existing timber productions records, and 13 C measurements in tree stems. Tree plantations had cooler surface temperatures (−5°C on average) and evaporated more water (+80% on average) than grasslands at all times and across all sites. Absolute ET differences between grasslands and plantations ranged from ∼0.6 to 2 mm day −1 and annual up‐scaling suggested values of ∼630 and ∼1150 mm yr −1 for each vegetation type, respectively. The temporal variability of ET was significantly lower in plantations compared with grasslands (coefficient of variation 36% vs. 49%). Daily ET increased as the water balance became more positive (accumulated balance for previous 18 days) with a saturation response in grassland vs. a continuous linear increase in plantations, suggesting lower ecophysiological limits to water loss in tree canopies compared with the native vegetation. Plantation ET was more strongly affected by soil texture than grassland ET and peaked in coarse textured sites followed by medium and fine textured sites. Timber productivity as well as 13 C concentration in stems peaked in medium textured sites, indicating lower water use efficiency on extreme textures and suggesting that water limitation was not responsible for productivity declines towards finer and coarser soils. Our study highlighted the key role that vegetation type plays on evapotranspiration and, therefore, in the hydrological cycle. Considering that tree plantations may continue their expansion over grasslands, problematic changes in water management and, perhaps, in local climate can develop from the higher evaporative water losses of tree plantations.

Exploratory Factor Analysis and Principal Component Analysis are two data analysis methods that are commonly used in psychological research. When applying these techniques, it is important to determine how many factors to retain. This decision is sometimes based on a visual inspection of the Scree plot. However, the Scree plot may at times be ambiguous and open to interpretation. This paper aims to explore a number of graphical and computational improvements to the Scree plot in order to make it more valid and informative. These enhancements are based on dynamic and interactive data visualization tools, and range from adding Parallel Analysis results to "linking" the Scree plot with other graphics, such as factor-loadings plots. To illustrate our proposed improvements, we introduce and describe an example based on real data on which a principal component analysis is appropriate. We hope to provide better graphical tools to help researchers determine the number of factors to retain.

In this work we explore the capabilities of two noise-assisted EMD methods: Ensemble EMD (EEMD) and the recently proposed Complete Ensemble EMD with Adaptive Noise (CEEMDAN), to recover a pure tone embedded in different kinds of noise, both stationary and nonstationary. Experiments are carried out for assessing their performances with respect to the level of the added noise and the number of realizations used for averaging. The obtained results partly support empirical recommendations reported in the literature while evidencing new distinctive features. While EEMD presents quite different behaviors for different situations, CEEMDAN evidences some robustness with an almost unaffected performance for the studied cases.

Gyroscopes have been proposed as sensors for ambulatory gait analysis and functional electrical stimulation systems. Accurate determination of the Initial Contact of the foot with the floor (IC) and the final contact or Foot Off (FO) on different terrains is important. This paper describes the evaluation of a gyroscope placed on the shank for determination of IC and FO in subjects walking outdoors on level ground, and up and down an incline. Performance was compared with a reference pressure measurement system. The mean difference between the gyroscope and the reference was less than -25 ms for IC and less than 75 ms for FO for all terrains. Detection success was over 98%. These results provide preliminary evidence supporting the use of the gyroscope for gait event detection on inclines as well as level walking.

BACKGROUND: Voluntarily sending sexual content (e.g., photos, videos) among adolescents via the Internet and mobile phones, a phenomenon called sexting , is receiving increasing social and research attention. The aims of this study were: 1) to analyze the prevalence and trends of sexting among adolescents by gender and age and 2) to examine the personality profile of adolescents that participated in sexting. METHOD: The sample consisted of 3,223 Spanish adolescents from 12 to 17 years of age (49.9% female; mean age = 14.06, SD = 1.37) who anonymously and voluntarily completed self-report questionnaires on sexting and the big five personality factors. RESULTS: The overall prevalence of sexting was 13.5%. The prevalence was 3.4% at 12 years old and increased to 36.1% at 17 years of age, showing a growing and significant linear trend. Overall, no differences were found between males and females. The personality profile of those involved in sexting was characterized by higher Extraversion and Neuroticism and by lower scores in Conscientiousness and Agreeableness. CONCLUSIONS: Given its high prevalence, beyond adopting a perspective based on the dangers of sexting, an educational approach that emphasizes responsible and informed use of information and communication technologies is necessary.

In arid regions throughout the world, shallow phreatic aquifers feed natural oases of much higher productivity than would be expected solely from local rainfall. In South America, the presence of well-developed Prosopis flexuosa woodlands in the Monte Desert region east of the Andes has puzzled scientists for decades. Today these woodlands provide crucial subsistence to local populations, including descendants of the indigenous Huarpes. We explore the vulnerability and importance of phreatic groundwater for the productivity of the region, comparing the contributions of local rainfall to that of remote mountain recharge that is increasingly being diverted for irrigated agriculture before it reaches the desert. We combined deep soil coring, plant measurements, direct water-table observations, and stable-isotopic analyses (2H and 18O) of meteoric, surface, and ground waters at three study sites across the region, comparing woodland stands, bare dunes, and surrounding shrublands. The isotopic composition of phreatic groundwaters (delta2H: -137 per thousand +/- 5 per thousand) closely matched the signature of water brought to the region by the Mendoza River (-137 per thousand +/- 6 per thousand), suggestin that mountain-river infiltration rather than in situ rainfall deep drainage (-39 per thousand +/- 19 per thousand) was the dominant mechanism of recharge. Similarly, chloride mass balances determined from deep soil profiles (> 6 m) suggested very low recharge rates. Vegetation in woodland ecosystems, where significant groundwater discharge losses, likely >100 mm/yr occurred, relied on regionally derived groundwater located from 6.5 to 9.5 m underground. At these locations, daily water-table fluctuations of 10 mm, and stable-isotopic measurements of plant water, indicated groundwater uptake rates of 200-300 mm/yr. Regional scaling suggests that groundwater evapotranspiration reaches 18-42 mm/yr across the landscape, accounting for 7 17% of the Mendoza River flow regionally. Our study highlights the reliance of ecosystem productivity in natural oases on Andean snowmelt, which is increasingly being diverted to one of the largest irrigated regions of the continent. Understanding the ecohydrological coupling of mountain and desert ecosystems here and elsewhere should help managers balance production agriculture and conservation of unique woodland ecosystems and the rural communities that rely on them.

The colonization of surfaces by bacteria is a widespread phenomenon with consequences on environmental processes and human health. While much is known about the molecular mechanisms of surface colonization, the influence of the physical environment remains poorly understood. Here we show that the colonization of non-planar surfaces by motile bacteria is largely controlled by flow. Using microfluidic experiments with Pseudomonas aeruginosa and Escherichia coli, we demonstrate that the velocity gradients created by a curved surface drive preferential attachment to specific regions of the collecting surface, namely the leeward side of cylinders and immediately downstream of apexes on corrugated surfaces, in stark contrast to where nonmotile cells attach. Attachment location and rate depend on the local hydrodynamics and, as revealed by a mathematical model benchmarked on the observations, on cell morphology and swimming traits. These results highlight the importance of flow on the magnitude and location of bacterial colonization of surfaces.

Grain yield improvement of maize ( Zea mays L.) hybrids has been associated with delayed leaf senescence. The objective of this study was to quantify the vertical profile of leaf senescence during the grain‐filling period in an older hybrid (‘Pride 5’) and two more recent maize hybrids (‘Pioneer 3902’ and ‘Pioneer 3893’). Leaf senescence was rated visually from silking to maturity on each individual leaf across the vertical leaf‐area profile along the stem of maize plants growing in the field at 1, 3.5, and 12 plants m −2 near Elora, ON, Canada, during the 1999 to 2001 growing seasons. Maximum leaf area index (LAI) at silking was greater in newer hybrids than in the older hybrid. Rate of leaf senescence across hybrids and plant population densities progressed at a linear rate of 0.44% d −1 during the first half of the grain‐filling period, whereas the rate was 1.87% d −1 during the second half of the grain‐filling period. Rates of leaf senescence were 3.4 and 2.1 times greater in the older hybrid than in the newer hybrids during the first and second half of the grain‐filling period, respectively. During the first half of the grain‐filling period, leaf senescence increased from the medium to the highest plant population density, whereas rates of senescence during the second half of the grain‐filling period declined with an increase in plant population density for the older hybrid and rates were lowest at the medium plant population density for the newer hybrids. A top–bottom profile of leaf senescence was observed during the second half of the grain‐filling period, with leaves in the central section of the canopy being the last leaves to senesce, and this phenomenon was more marked in the newer hybrids.

Because emerging adulthood is a culturally constructed period of life course, it is interesting to explore whether it exists in Argentina, a Catholic Latin American country of Southern European descent.

A Correction to this paper has been published: https://doi.org/10.1038/s41597-021-00851-9.

Surface electroencephalography is a standard and noninvasive way to measure electrical brain activity. Recent advances in artificial intelligence led to significant improvements in the automatic detection of brain patterns, allowing increasingly faster, more reliable and accessible Brain-Computer Interfaces. Different paradigms have been used to enable the human-machine interaction and the last few years have broad a mark increase in the interest for interpreting and characterizing the "inner voice" phenomenon. This paradigm, called inner speech, raises the possibility of executing an order just by thinking about it, allowing a "natural" way of controlling external devices. Unfortunately, the lack of publicly available electroencephalography datasets, restricts the development of new techniques for inner speech recognition. A ten-participant dataset acquired under this and two others related paradigms, recorded with an acquisition system of 136 channels, is presented. The main purpose of this work is to provide the scientific community with an open-access multiclass electroencephalography database of inner speech commands that could be used for better understanding of the related brain mechanisms.

There are controversial results among the available experimental data of the germanium sulfide band gap, as well as between these results and the theoretical model-based band calculations published to date. To elucidate this situation, we performed an ab initio calculation of its electronic structure adopting the local density and generalized gradient approximations for the exchange-correlation potential. In addition, these calculations were carried out with and without the inclusion of the spin-orbit interaction. The main difference between our calculations and previous experimental and theoretical results is that we found several critical points in the valence and conduction bands that compete in defining the gap. This explains the diversity of the existent experimental results, which is also a consequence of the strong crystal anisotropy. Also, we suggest the important role of the $s\text{\ensuremath{-}}\mathrm{Ge}$ states contribution at the edge of the valence band. Based on our electronic structure, we discuss the experimental core spectra and optical properties of germanium sulfide. We found an excellent agreement between our results and the available experimental core spectra data. Furthermore, our calculated optical functions of $\mathrm{GeS}$ were satisfactorily compared against existing experimental data and they explain the origin of the optical transitions.

BACKGROUND: Preparing for HPV vaccine programs, studies are needed of HPV infection in different populations. GOAL: The goal was to evaluate HPV prevalence and determinants in Concordia, Argentina. STUDY DESIGN: A stratified random sample of 1786 households was obtained. Consenting women aged > or =15 years were interviewed and underwent examination, including colposcopy. Cells were collected for a Papanicolaou smear and HPV DNA testing with GP5+/6+ primer-mediated PCR-EIA. RESULTS: PCR was performed on specimens from 987 women. Prevalence among women reporting no previous sexual activity was 3%, and among sexually active women it was 17.7%, peaking at <25 years of age and decreasing to a minimum at > or =65 years of age. However, low-risk types had similar prevalence (approximately 5%) in all age groups. HPV16 (4.0%), HPV35 (2.6%), and other high-risk types were the most common. Almost half of infections were multiple. Younger women initiated sexual activity earlier and had more partners. The main determinants of HPV detection were lifetime number of sex partners and vaginal discharge. CONCLUSION: A clear pattern of decreasing prevalence of HPV with age was observed. This could be explained by development of immunity against specific types over time or related to a cohort effect associated with a recent spread of HPV in this population after recent changes in sexual behavior.

Studies of microbial communities vary widely in terms of analysis methods. In this growing field, the wide variety of diversity measures and lack of consistency make it harder to compare different studies. Most existing alpha diversity metrics are inherited from other disciplines and their assumptions are not always directly meaningful or true for microbiome data. Many existing microbiome studies apply one or some alpha diversity metrics with no fundamentals but also an unclear results interpretation. This work focuses on a theoretical, empirical, and comparative analysis of 19 frequently and less-frequently used microbial alpha diversity metrics grouped into 4 proposed categories, including key features of every analyzed metric with their mathematical assumptions, to provide a deeper understanding of the existing metrics and a practical implementation guide for future studies. Key metrics that should be required in microbiome analysis include richness, phylogenetic diversity, entropy, dominance of a few microbes over others, and an estimate of unobserved microbes. Collectively, these metrics contribute to a comprehensive set of analyses characterizing samples, allowing the determination of key aspects that might be otherwise obscured by partial or biased information. These guidelines enable further detailed analysis by each author according to their specific interests and clinical trials. Several practical examples are provided to illustrate how these recommendations improve the quality and depth of information obtained, facilitating better interpretation when working with microbiome data. These guidelines can be applied to both existing and future research studies, enhancing the standardization, consistency, and robustness of the analyses conducted. This approach aims to improve the capture of biological diversity, leading to better interpretations and insights.

After several years of loud and clear rejection, the idea of a public cognitive deficit insistently reappears in the agenda of Science Communication and Public Understanding of Science studies. This essay addresses two different kinds of reason - practical and epistemic - converging at that point. In the first part, it will be argued that the hypothesis of the lack of knowledge among laypeople and its controversial relationships with their interests and attitudes towards science prevails because it is an intuitive and optimistic way to frame the gap between science and society and, therefore, to cope with its causes and consequences. In the second part, a deeper level of reasons will be examined, in order to show that the persistence of the idea has its roots in the objective epistemic asymmetry between scientists and the public, the scope of which is not always properly judged. To recognize this asymmetry as a previous condition for their interactions may help to surpass the byzantine debate: deficit yes or no and open up original questions for the field, summarized in the closing remarks.

Accurate estimates of total leaf area and the vertical leaf area profile are important in process‐based crop growth models. The bell‐shaped function that quantifies the area‐per‐leaf profile of a maize ( Zea mays L.) plant can be used to estimate the area‐per‐leaf profile. The objectives of this study were to quantify the effects of maize hybrid, soil N, plant density, and row spacing on the coefficients of the bell‐shaped function. The coefficients of the bell‐shaped function that quantify (i) the breadth of the area‐per‐leaf profile, (ii) the skewness of the area‐per‐leaf profile, and (iii) the position of the largest leaf were estimated using nonlinear regression in four datasets. Datasets consisted of the fully expanded leaf areas of all leaves on maize plants grown in studies performed in Ontario, Canada, between 1997 and 2001 that included combinations of maize hybrids, plant densities, N levels, and row spacing. Observations fitted well to the bell‐shaped function ( r 2 &gt; 0.95). The breadth of the area‐per‐leaf profile decreased under high soil N level and high plant density, and was lower for a newer than an older hybrid, whereas the opposite occurred with the position of the largest leaf. In contrast, the degree of skewness was not significantly altered by any of the factors examined in this study. Because of the relatively small impact of the examined agronomic factors on the coefficients of the bell‐shaped function, a general model using mean coefficient values was validated with independent datasets. Results showed that this general bell‐shaped function is a robust predictor of the area‐per‐leaf profile in maize.