First-passage time of a Brownian searcher with stochastic resetting to random positions.

We study the effect of a resetting point randomly distributed around the origin on the mean first-passage time of a Brownian searcher moving in one dimension. We compare the search efficiency with that corresponding to reset to the origin and find that the mean first-passage time of the latter can be larger or smaller than the distributed case, depending on whether the resetting points are symmetrically or asymmetrically distributed. In particular, we prove the existence of an optimal reset rate that minimizes the mean first-passage time for distributed resetting to a finite interval if the target is located outside this interval. When the target position belongs to the resetting interval or it is infinite then no optimal reset rate exists, but there is an optimal resetting interval width or resetting characteristic scale which minimizes the mean first-passage time. We also show that the first-passage density averaged over the resetting points depends on its first moment only. As a consequence, there is an equivalent point such that the first-passage problem with resetting to that point is statistically equivalent to the case of distributed resetting. We end our study by analyzing the fluctuations of the first-passage times for these cases. All our analytical results are verified through numerical simulations.

Ergodic properties of Brownian motion under stochastic resetting.

We study the ergodic properties of one-dimensional Brownian motion with resetting. Using generic classes of statistics of times between resets, we find respectively for thin- or fat-tailed distributions the normalized or non-normalized invariant density of this process. The former case corresponds to known results in the resetting literature and the latter to infinite ergodic theory. Two types of ergodic transitions are found in this system. The first is when the mean waiting time between resets diverges, when standard ergodic theory switches to infinite ergodic theory. The second is when the mean of the square root of time between resets diverges and the properties of the invariant density are drastically modified. We then find a fractional integral equation describing the density of particles. This finite time tool is particularly useful close to the ergodic transition where convergence to asymptotic limits is logarithmically slow. Our study implies rich ergodic behaviors for this nonequilibrium process which should hold far beyond the case of Brownian motion analyzed here.

EMG Data Augmentation for Grasp Classification Using Generative Adversarial Networks.

Electromyography (EMG) has been used as an interface for the control of robotic hands for decades but with the improvement of embedded electronics and decoding algorithms, many applications are now envisaged by companies. Deep learning has shown the possibility to increase decoding performance but it requires large amounts of data to show its full capabilities. However, recording such amounts of EMG signals face several issues since recording hours of data from patients is very time-consuming and can result in muscle fatigue. We explore a deep learning data augmentation strategy using generative adversarial networks (GANs) to create high-quality synthetic data to increase the performance of grasp classification.

Low Prevalence of ETV6::RUNX1 Fusion Gene in a Hispanic Population.

ETV6::RUNX1 is a genetic rearrangement of good prognosis in children with acute lymphoblastic leukemia (ALL). In Mexico, its prevalence is low in comparison with Caucasian populations. We developed a novel TaqMan one-step RT-qPCR approach to assess the prevalence of four genetic rearrangements in a cohort of Hispanic children with ALL from Mexico City. The prevalence of common fusion gene transcripts was as follows: TCF3::PBX1 7.7%; BCR::ABL1p 190 3.3%; and KMT2A::AFF1 2.8%, and ETV6::RUNX1was observed with low prevalence (10.5%) in comparison to that reported for developed countries. This is consistent with previous findings on Mexican children with ALL and similar to those reported on children from Hispanic populations. The confirmation of a low prevalence of ETV6::RUNX1 in children of a Hispanic origin represents an advancement in the description of genetic factors of ALL in these populations.

Neumomediastino en pacientes con COVID-19 ingresados en UCI: serie de casos y revisión de la literatura / [Pneumomediastinum in patients with COVID-19 admitted to the ICU: case series and review of the literature]

Tras declaración de pandemia en febrero de 2020, se observa un aumento de casos de neumonías bilaterales con insuficiencia respiratoria grave, complicadas a su vez con neumomediastino. Se describe una serie de cuatro pacientes con neumomediastino asociado a distress respiratorio por neumonía por SARS-CoV-2 ingresados en cuidados intensivos del Hospital Universitario Rey Juan Carlos entre diciembre 2020 y enero 2021. En su mayoría son hombres de mediana edad, sin patología pulmonar previa, no fumadores, que han necesitado ventilación mecánica. El diagnóstico de neumomediastino se ha realizado mediante tomografía computarizada y el tratamiento ha sido conservador, con resolución total en todos los casos. Aunque esta complicación es un indicador de destrucción pulmonar y condiciona cambios en el manejo de la ventilación mecánica, no parece estar directamente relacionada con peor pronóstico o aumento de la mortalidad. (AU)

After the declaration of a pandemic in February 2020, an increase in cases of bilateral pneumonia with severe respiratory failure, in turn complicated by pneumomediastinum, has been observed. A series of four patients with pneumomediastinum associated with respiratory distress due to SARS-CoV-2 pneumonia admitted to intensive care at the Rey Juan Carlos University Hospital between December 2020 and January 2021 is described. Most of them are middle-aged men, without previous pulmonary pathology, non- smokers, who have required mechanical ventilation. The diagnosis of pneumomediastinum has been made by computed tomography and the treatment has been conservative, with complete resolution in all cases. Although this complication is an indicator of lung destruction and determines changes in the management of mechanical ventilation, it does not seem to be directly related to a worse prognosis or increased mortality. (AU)

Paternal effects in the initiation of migratory behaviour in birds.

What determines why some birds migrate and others do not? This question is fundamental to understanding how migratory systems are responding to environmental changes, but the causes of individual migratory behaviours have proven difficult to isolate. We show that, in a partially migratory population of Eurasian oystercatchers (Haematopus ostralegus), the migratory behaviour of progeny follows paternal but not maternal behaviour, and is unrelated to timing of hatching or fledging. These findings highlight the key role of social interactions in shaping the migratory behaviour of new generations, and thus the spatio-temporal distribution of migratory populations.

Unexpected better outcome in a liver transplant recipient with COVID-19: a beneficial effect of tacrolimus? / Evolución clínica en un receptor de trasplante de hígado con la COVID-19: ¿Un efecto benéfico del tacrolimus?

Coronavirus disease 2019 (COVID-19) is a serious respiratory illness caused by SARS-CoV-2. There is controversy about whether their immunosuppressive status is a risk factor or a protective factor for developing severe disease. We report herein the clinical outcome of three family members that had COVID-19 infection, presenting with and without different risk factors that have been described in more severe disease. Paradoxically, the patient with more risks of developing a severe disease, a 64-year-old woman, 2-years liver transplant recipient under treatment with tacrolimus, presented a similar outcome compared to the two other members of the family. She showed shorter hospitalization time, similar clinical outcome with fewer oxygen needs. The present clinical observation raises the question about the possible beneficial effect of tacrolimus in patients with COVID-19. Indeed, tacrolimus (FK-506) have an inhibitory effect on human coronaviruses by: 1) an antiviral effect by binding to the FK-506-binding proteins (FKBP) with a subsequent inhibition of their peptidyl-prolyl cis/trans isomerase (PPIase) activity, which seems to be important for the coronavirus life cycle; and 2) regulating the immune response by the inhibition of the activity of the nuclear factor of activated T-cells (NFAT) required for immunosuppression. The present observation states that liver recipients' patients with COVID-19 may not have worse outcomes when compared with other patients that have COVID-19 risk factors and puts in evidence the two mechanisms related to tacrolimus.

Social-psychological determinants of farmer intention to adopt nutrient best management practices: Implications for resilient adaptation to climate change.

Successful adaptation to global climate change and enhancement of agricultural watersheds' resilience requires widespread use of Nutrient Best Management Practices (NBMPs) by farms of all sizes. In the US, adoption of many NBMP practices is voluntary and insufficient to achieve local and downstream conservation objectives. Despite evidence that both social-psychological factors and socio-economic factors influence farmer decision-making, very few studies of farmers' decision-making related to NBMP adoption combine these two factor groups in a theoretically rigorous way. To better understand farmers' management decisions, we test the social-psychological Theory of Planned Behavior (TPB) to determine the relative influence of attitudes, perceived social norms, and perceived behavioral control on adoption of nine NBMPs. A survey was designed by the research team and implemented by the U.S. Department of Agriculture-National Agricultural Statistics Service (USDA-NASS) in 2013, and replicated in 2016, on a stratified sample of 129 farmers (including panel data on 56 farmers). Farmers were located in the Missisquoi, and Lamoille River watersheds of the Lake Champlain Basin in the Northeast region of the United States. Survey responses revealed variation in past adoption of NBMPs was sensitive to practice type and farm size. We developed nine weighted structural equation models to test endogenous (social-psychological) and exogenous (policy, economic and demographic) predictors of farmer intention to adopt NBMPs. We found that perceived behavioral control had the largest effect size and strongest statistical significance on the farmers' expressed intentions to adopt NBMPs in the future. For a subset of NBMPs, perceived social norms and farmer attitudes toward these NBMPs were each also significant drivers of intention to adopt individual practices. Among the exogenous variables, we found that large farm size, college education, and having a conservation easement all had a positive influence on farmers' intention to adopt NBMPs. This study suggests that for widespread adoption of NBMPs, environmental managers, policy makers, and program developers should be attentive to farmers' perceived behavioral control, and support the design and execution of outreach and technical assistance programs that build on drivers of farmers' decision making.

Dolor psíquico: una mirada a su condición actual / Psychic pain: a look to its current condition

Resumen No obstante, el dolor ha permanecido ligado a la existencia humana y que la asistencia al dolor es una de las principales funciones de los equipos de salud, el dolor psíquico no ha estado presente en la formación médica ni en la investigación. En el presente estudio se plantearon dos preguntas: ¿Cuál es el estado actual de la investigación considerando las perspectivas psicológicas y neurobiológicas del dolor psicológico? y ¿qué lugar ocupa el dolor psicológico en la asistencia actual de los pacientes? Los objetivos fueron: 1) Revisar la significación del dolor en su perspectiva histórica y su relación con la existencia humana; 2) Examinar las bases neurobiológicas del dolor físico y psíquico; 3) Reflexionar acerca del lugar que le cabe al dolor psíquico en los programas de cuidados paliativos del dolor. Como metodología se revisó la literatura publicada en Medline, Scopus y Scielo tomando las palabras claves: Dolor Psíquico, Dolor Mental y Dolor Emocional. Se revisan las razones por las cuales el dolor psíquico ha permanecido postergado, considerando que la experiencia del dolor es una experiencia psíquica debido a que puede haber dolor psíquico sin dolor físico, pero no al revés. El dolor psíquico puede ser tan real como otras formas de dolor más aun considerando que puede ser tan severo como para exponer a una persona al riesgo suicida. Se analizan las estructuras involucradas en el dolor psíquico y físico y se comenta acerca del rol de los médicos en su deber de aliviar el dolor.

Although pain has been present trough human history and that its assistance is one of the most important activities of health teams, psychic pain hasn't been present properly neither in medical education nor research. In order to assess this topic the author has carried out a review following these two questions: What is the state of the art considering psychological and neurobiological perspectives of psychic pain? and which place is occupying psychic pain in the current assistance of patients? The proposed objectives were: 1) To evaluate historical aspects of pain and its place in human life; 2) To evaluate neurobiological basis of psychic and somatic pain and 3) To reflect about the place psychic pain has currently in Paliative Care Programs. The methodology was the review of current literature published in Medline, Scopus and Scielo considering the following key words: Psychological Pain, Mental Pain and Emotional Pain. Special consideration is given to how this topic has been postponed and the reasons for this situation, considering that the whole experience of pain is psychological, as there may be psychical pain without physical pain but not otherwise. Psychic pain is not less real than other kind of pain; it may be even more severe as to put a person at risk of suicide. Mention is made about the boundaries between physical and psychic pain considering that they are not clear, as they involve similar structures. The role of medical doctors in helping to alleviate pain of patients is addressed.

Gross anatomy of the heart of the alpaca (Vicugna pacos, Linnaeus 1758).

The available information about anatomical characteristics of the cardiovascular system of the alpaca (Vicugna pacos, Linnaeus 1758) is scarce. The general objective of this work was to describe its heart anatomy. We dissected six adult animals and five neonates. The heart of the alpaca was located in the middle mediastinum, with a craniocaudal extension from the third to the sixth rib. No ligament that connected the fibrous pericardium to the sternum or to the diaphragm was detected. In the right atrium, there was a developed crista terminalis and small pectinate muscles. In the right ventricle, the septomarginal trabecula was very large. From the proximities of the interventricular septum arose small septomarginal trabeculae that ended in carnous trabeculae of the septal wall. The left atrium included little developed pectinate muscles. On the left ventricle, both papillary muscles were bilobed. Two left septomarginal trabeculas were detected in this ventricle. The left subclavian artery was originated from the aortic arch separately from the brachiocephalic trunk, and bicarotid trunk was present. The other branches of the subclavian artery were similar to the domestic ruminants. The arterial supply of the heart was of the right type. In conclusion, the heart anatomy of alpaca and the irrigation of thoracic cavity were more similar to those of old world camels and different from domestic ruminants.

Pacientes difíciles o relaciones difíciles en Psiquiatría: Un estudio de casos y controles / Difficult patients or difficult relationships in Psychiatry: A case control study

Resumen Los pacientes difíciles en Psiquiatría imponen un trabajo intenso a los profesionales y grupos de trabajo de salud mental. Las estadísticas muestran que la frecuencia puede alcanzar hasta un tercio de los pacientes habiendo sido estudiados mayormente en Salud Mental y Atención Primaria. Mediante un estudio de casos y controles nos propusimos caracterizar los pacientes difíciles y conocer los factores involucrados en las diferencias observadas. Se obtuvo una muestra por conveniencia. Se seleccionaron dos controles por cada caso, pareados por rango de edad y sexo. Hipótesis: Características de personalidad de los pacientes permiten explicar las diferencias observadas en la frecuencia de presentación de los casos difíciles en Psiquiatría. Resultados: No se observaron diferencias significativas en la distribución por edad, sexo, estado civil, escolaridad tiempo de tratamiento y en los diagnósticos clínicos (eje I del DSM), pero sí fueron significativas las diferencias en el número de medicamentos utilizados, el tiempo en psicoterapia, la intervención social y la presencia de trastornos de la personalidad, siendo más frecuentes en los casos (pacientes difíciles) por lo que se confirma la hipótesis de trabajo. Discusión: Se discute el sentido de calificar paciente difícil, considerando que se trata más bien de "situaciones difíciles". Estas situaciones se observaron con mayor frecuencia ante la presencia de Trastornos de la Personalidad. Se analiza las implicancias al abordar este tipo de condiciones. A pesar de la importancia del problema, el tema ha sido poco estudiado en nuestro medio.

Difficult patients involve a great deal of work to professionals and Mental Health teams. Epidemiological data show that the rate is up to one third of the patients having been mostly studied in Mental Health and Primary Care. Using a case control design the objective of this study was to characterize difficult patients and the factors that could explain the differences observed. A convenience sample was chosen. Two controls were taken by each case. Controls were paired by sex and age. Hypothesis: Characteristics of personality of patients, allow us to explain the differences observed in difficult patients in Psychiatry. Results: There were no significant differences according by age, sex, marital status, educational level, time span of treatment and clinical diagnosis, but significant differences were observed in the number of medications taken, time span in psychotherapy, social work assistance and personality disorders, being more frequent in difficult patients. Discussion: It´s discussed the convenience of the expression difficult patient, rather than difficult situation considering the review of research and the clinical experience. Difficult situations are found more frequently in personality disorders. It´s analyzed the implications when dealing with this sort of conditions. Although the importance of this topic, it has been poorly studied in this milieu.

Optimal search strategies of space-time coupled random walkers with finite lifetimes.

We present a simple paradigm for detection of an immobile target by a space-time coupled random walker with a finite lifetime. The motion of the walker is characterized by linear displacements at a fixed speed and exponentially distributed duration, interrupted by random changes in the direction of motion and resumption of motion in the new direction with the same speed. We call these walkers "mortal creepers." A mortal creeper may die at any time during its motion according to an exponential decay law characterized by a finite mean death rate ω(m). While still alive, the creeper has a finite mean frequency ω of change of the direction of motion. In particular, we consider the efficiency of the target search process, characterized by the probability that the creeper will eventually detect the target. Analytic results confirmed by numerical results show that there is an ω(m)-dependent optimal frequency ω=ω(opt) that maximizes the probability of eventual target detection. We work primarily in one-dimensional (d=1) domains and examine the role of initial conditions and of finite domain sizes. Numerical results in d=2 domains confirm the existence of an optimal frequency of change of direction, thereby suggesting that the observed effects are robust to changes in dimensionality. In the d=1 case, explicit expressions for the probability of target detection in the long time limit are given. In the case of an infinite domain, we compute the detection probability for arbitrary times and study its early- and late-time behavior. We further consider the survival probability of the target in the presence of many independent creepers beginning their motion at the same location and at the same time. We also consider a version of the standard "target problem" in which many creepers start at random locations at the same time.

EBV, HCMV, HHV6, and HHV7 screening in bone marrow samples from children with acute lymphoblastic leukemia.

Acute lymphoblastic leukemia (ALL) is the most common cancer in childhood worldwide and Mexico has reported one of the highest incidence rates. An infectious etiology has been suggested and supported by epidemiological evidences; however, the identity of the involved agent(s) is not known. We considered that early transmitted lymphotropic herpes viruses were good candidates, since transforming mechanisms have been described for them and some are already associated with human cancers. In this study we interrogated the direct role of EBV, HCMV, HHV6, and HHV7 human herpes viruses in childhood ALL. Viral genomes were screened in 70 bone marrow samples from ALL patients through standard and a more sensitive nested PCR. Positive samples were detected only by nested PCR indicating a low level of infection. Our result argues that viral genomes were not present in all leukemic cells, and, hence, infection most likely was not part of the initial genetic lesions leading to ALL. The high statistical power of the study suggested that these agents are not involved in the genesis of ALL in Mexican children. Additional analysis showed that detected infections or coinfections were not associated with prognosis.

Interactions between carbon sequestration and shade tree diversity in a smallholder coffee cooperative in El Salvador.

Agroforestry systems have substantial potential to conserve native biodiversity and provide ecosystem services. In particular, agroforestry systems have the potential to conserve native tree diversity and sequester carbon for climate change mitigation. However, little research has been conducted on the temporal stability of species diversity and aboveground carbon stocks in these systems or the relation between species diversity and aboveground carbon sequestration. We measured changes in shade-tree diversity and shade-tree carbon stocks in 14 plots of a 35-ha coffee cooperative over 9 years and analyzed relations between species diversity and carbon sequestration. Carbon sequestration was positively correlated with initial species richness of shade trees. Species diversity of shade trees did not change significantly over the study period, but carbon stocks increased due to tree growth. Our results show a potential for carbon sequestration and long-term biodiversity conservation in smallholder coffee agroforestry systems and illustrate the opportunity for synergies between biodiversity conservation and climate change mitigation.

Reaction-subdiffusion front propagation in a comblike model of spiny dendrites.

Fractional reaction-diffusion equations are derived by exploiting the geometrical similarities between a comb structure and a spiny dendrite. In the framework of the obtained equations, two scenarios of reaction transport in spiny dendrites are explored, where both a linear reaction in spines and nonlinear Fisher-Kolmogorov-Petrovskii-Piskunov reactions along dendrites are considered. In the framework of fractional subdiffusive comb model, we develop a Hamilton-Jacobi approach to estimate the overall velocity of the reaction front propagation. One of the main effects observed is the failure of the front propagation for both scenarios due to either the reaction inside the spines or the interaction of the reaction with the spines. In the first case the spines are the source of reactions, while in the latter case, the spines are a source of a damping mechanism.

Allergy and acute leukaemia in children with Down syndrome: a population study. Report from the Mexican inter-institutional group for the identification of the causes of childhood leukaemia.

BACKGROUND: Allergies have been described as protective factors against the development of childhood acute leukaemia (AL). Our objective was to investigate the associations between allergy history and the development of AL and acute lymphoblastic leukaemia (ALL) in children with Down syndrome (DS). METHODS: A case-control study was performed in Mexico City. The cases (n=97) were diagnosed at nine public hospitals, and the controls (n=222) were recruited at institutions for children with DS. Odds ratios (OR) were calculated. RESULTS: Asthma was positively associated with AL development (OR=4.18; 95% confidence interval (CI): 1.47-11.87), whereas skin allergies were negatively associated (OR=0.42; 95% CI: 0.20-0.91). CONCLUSION: Our findings suggest that allergies and AL in children with DS share biological and immune mechanisms. To our knowledge, this is the first study reporting associations between allergies and AL in children with DS.

Food sovereignty: an alternative paradigm for poverty reduction and biodiversity conservation in Latin America.

Strong feedback between global biodiversity loss and persistent, extreme rural poverty are major challenges in the face of concurrent food, energy, and environmental crises. This paper examines the role of industrial agricultural intensification and market integration as exogenous socio-ecological drivers of biodiversity loss and poverty traps in Latin America. We then analyze the potential of a food sovereignty framework, based on protecting the viability of a diverse agroecological matrix while supporting rural livelihoods and global food production. We review several successful examples of this approach, including ecological land reform in Brazil, agroforestry, milpa, and the uses of wild varieties in smallholder systems in Mexico and Central America. We highlight emergent research directions that will be necessary to assess the potential of the food sovereignty model to promote both biodiversity conservation and poverty reduction.

A rapid protocol for purification of total RNA for tissues collected from pigs at a slaughterhouse.

Since RNA extraction is a crucial step in many molecular techniques, the protocols for sample collection and RNA purification need to be adapted to optimize their performance when samples are collected from animals at commercial facilities. Here we provide an RNA purification protocol for animal tissues collected from slaughterhouses. This protocol, modified from other techniques, uses TRIzol Reagent. Sample collection was performed wearing sterile gloves and facemasks, using sterile surgical instruments, and no longer than 8 min spent for each sample. A 0.9% sterile sodium chloride solution was used to wash the tissue before each sample collection. The whole process of RNA extraction was performed under cold environment and sterile conditions. This protocol produced good RNA yields (50 µg RNA per 100 mg tissue), good integrity and purity (Abs(260/280) from 1.8 to 2.0), from tissues such as liver, muscle, hypophysis, adipose tissue, and intestinal mucosa, in less than 2 h.

[Renal bilharzioma: A case report]. / Bilharziome rénal : à propos d'une observation.

Renal bilharzioma is an exceptional localization that occurs as a complication of urogenital bilharzioma. The authors report the case of a renal bilharzioma, in a 7-year-old patient, being considered as a nephroblastoma. The investigations revealed a large abdominal mass with solid component. She underwent neoadjuvant chemotherapy and radical nephrectomy. The histological examination of the specimen concluded to renal bilharzioma. The authors underline the difficulty of differential diagnosis with nephroblastoma. The diagnosis is often made after surgery by histological examination of the specimen.