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This study presents the effect of natural zeolite (NZ) on a nitrifying sequencing batch reactor for removing ibuprofen (IBP) and diclofenac (DFC) in the long term, including kinetics and microbial community. The research was conducted in two 2 L liquid-volume bioreactors, one with 5 g/L of NZ. Nitrogen load rates ranging between 5.8 and 8.5 mg N/L h were studied. Bioreactors were operated for 217 days, with IBP and DFC concentrations ranging between 20 and 2000 µg/L. The results showed that using NZ in a nitrifying SBR only improves IBP removal at low concentrations (40 µg/L). IBP and DFC do not affect the nitrification efficiency or kinetic of ammonia removal. In the presence of IBP and DFC, NZ also favored a higher relative abundance in the genus Nitrosomonas and the Bradyrhizobiaceae family (responsible for nitrite-oxidizing activity), allowing higher IBP degradations at low IBP concentrations. Finally, IBP and DFC stimulated heterotrophic nitrification.

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Ordered and disordered semiconductor superlattices represent structures with completely opposed properties. For instance, ordered superlattices exhibit extended Bloch-like states, while disordered superlattices present localized states. These characteristics lead to higher conductance in ordered superlattices compared to disordered ones. Surprisingly, disordered dimer superlattices, which consist of two types of quantum wells with one type always appearing in pairs, exhibit extended states. The percentage of dissimilar wells does not need to be large to have extended states. Furthermore, the conductance is intermediate between ordered and disordered superlattices. In this work, we explore disordered dimer superlattices in graphene. We calculate the transmission and transport properties using the transfer matrix method and the Landauer-Büttiker formalism, respectively. We identify and discuss the main energy regions where the conductance of random dimer superlattices in graphene is intermediate to that of ordered and disordered superlattices. We also analyze the resonant energies of the double quantum well cavity and the electronic structure of the host gated graphene superlattice (GGSL), finding that the coupling between the resonant energies and the superlattice energy minibands gives rise to the extended states in random dimer GGSLs.

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Little is known about the contribution of psychosocial factors related to mental healthcare use among Mexican-origin women from farmworker families. Therefore, this study assessed relationships between acculturative stress, depressive symptoms, mental healthcare service use, and preferences for seeking care. Linear and logistic regression models and chi-square tests were performed to analyze survey data from 78 Mexican-origin women from farmworker families. Women were recruited in collaboration with promotoras and completed measures of acculturative stress, depressive symptoms, and mental healthcare use and preferences. Overall, 29.5% of the sample reported clinically significant depressive symptomatology. Acculturative stress was positively associated with depressive symptoms (b = 0.43, 95%CI = 0.27,0.59) after controlling for years in the U.S., primary language, and demographic characteristics. In addition, acculturative stress was associated with lower odds of mental healthcare use (OR = 0.96) after controlling for years in the U.S. and depressive symptoms. However, this association was no longer statistically significant when controlling for health insurance status and access to transportation. Mexican-origin women with high levels of acculturative stress were significantly more likely to seek care from a psychiatrist/psychologist than their peers (54.3% vs. 45.7%); however, this preference was not indicative of their use of mental healthcare services. Results suggest that acculturative stress is a risk factor for depressive symptoms and might contribute to a delay in seeking mental healthcare services in Mexican-origin women from farmworker families. Thus, interventions for this group should address aspects of acculturative stress as a strategy to increase mental health services use.

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INTRODUCTION: as the population pyramid gets inverted, more active and longer lives are lived, geriatric patients with high energy trauma (HET) become more frequent; requiring more resources, getting worse results with more perioperative complications, coupled with a fragile state of health and osteopenia, make these fractures difficult to manage. With the hypothesis that the incidence of pelvic and acetabular fractures in the elderly due to HET is higher than that reported in the world literature, the research question was generated: What is the incidence of pelvic and acetabular fractures in the elderly due to HET, in a 5-year period? MATERIAL AND METHODS: with the authorization of the Ethics Committee, an observational study of a retrospective cohort was carried out, using medical records, identifying the incidence of these fractures, surgically treated in our institution Clínica Las Vegas, Medellin, Colombia, a level III hospital, from July 1, 2016 to June 30, 2021. RESULTS: a cumulative incidence of 1.95 new cases per 100,000 person-years was calculated, a prevalence of 13.8%; resulting in a higher incidence and prevalence, confirming our hypothesis. CONCLUSION: treatment should be aimed at improving quality of life with stable fixation, identification and treatment of associated injuries, minimizing the risk of mechanical complications and prioritizing the reinforcement of preventive measures, also in the improvement of male role behavior, whom, as it seems, will keep carrying out risky activities despite their age.

INTRODUCCIÓN: a medida que se invierte la pirámide poblacional, se viven vidas más largas y activas, se vuelven más frecuentes los pacientes geriátricos con trauma de alta energía; requiriendo más recursos, obteniéndose peores resultados, con más complicaciones perioperatorias, hacen a estas fracturas difíciles de manejar. Establecida la hipótesis de que la incidencia de las fracturas de pelvis y acetábulo, en el adulto mayor por trauma de alta energía, es superior a la reportada en la literatura mundial, se generó la pregunta de investigación: ¿Cuál es la incidencia de fracturas de pelvis y acetábulo por trauma de alta energía en el adulto mayor en un período de cinco años? MATERIAL Y MÉTODOS: una vez obtenida la autorización del Comité de Ética, se realizó un estudio observacional de una cohorte retrospectiva, utilizando registros médicos, identificando la incidencia de estas fracturas, tratadas quirúrgicamente en nuestro hospital de III nivel, Clínica Las Vegas, Medellín, Colombia, del 1 de Julio de 2016 a 30 de Junio de 2021. RESULTADOS: se calculó una incidencia acumulada de 1.95 nuevos casos por cada 100,000 personas-año, una prevalencia de 13.8%; resultando en una mayor incidencia y prevalencia, confirmándose nuestra hipótesis. CONCLUSIÓN: el tratamiento debe orientarse a mejorar la calidad de vida con una fijación estable, identificación y tratamiento de lesiones asociadas, minimizando el riesgo de complicaciones mecánicas y priorizar el reforzamiento de medidas preventivas y a la mejora del comportamiento del rol masculino, que aparentemente, seguirán realizando actividades de riesgo a pesar de su edad.

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Gaussian and Gaussian-related structures are quite attractive due to its versatility to modulate the electronic transport, including its possibility as electron filters. Here, we show that these non-conventional profiles are not the exception when dealing with Fermi velocity barriers in monolayer graphene. In particular, we show that Gaussian Fermi velocity graphene barriers (G-FVGBs) and Gaussian-pulsed-like Fermi velocity graphene superlattices (GPL-FVGSLs) can serve as electron band-pass filters and oscillating conductance structures. We reach this conclusion by theoretically studying the transmission and transport properties of the mentioned structures. The study is based on the continuum model, the transfer matrix method and the Landauer-Büttiker formalism. We find nearly flat transmission bands or pass bands for G-FVGBs modulable through the system parameters. The pass bands improve as the maximum ratio of Fermi velocities (ξmax) increases, however its omnidirectional range is reduced. These characteristics result in a decaying conductance (integrated transmission) withξmax. The integrated transmission remains practically unaltered with the size of the system due to the saturation of the electron pass band filtering. In the case of GPL-FVGSLs the GPL profile results in regions of high transmission probability that can merge as flat transmission minibands if the pulse fraction and the superlattice parameters are appropriately tuned. The GPL profile also results in conductance (integrated transmission) oscillations that can be multiplied or reduced in number by adjusting the pulse fraction as well as the superlattice parameters.

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BACKGROUND: The development and establishment of oral squamous cell carcinoma are confined to carcinogenesis, which involves oxidative stress via oxygen-free radical production as a hydroxyl radical (HO•), considered the most important cause of oxidative damage to basic biomolecules since it targets DNA strands. 8-Hydroxy-2´-deoxyguanosine (8-OHdG) is considered a free radical with a promutagenic capacity due to its ability to pair with adenosine instead of cytosine during replication. MATERIAL AND METHODS: We collected 30 paraffin-embedded tissue samples of OSCC from patients treated between 2013 and 2018. We recorded risk habits, disease stage, disease free survival and death with at least 3 years of follow-up. 8-Hydroxyguanosine was evaluated by immunohistochemistry and subsequently classified as weak-moderate or strong positive expression. Additionally, we noted whether it was expressed in the cytoplasm and/or nucleus. RESULTS: Most of the cases expressed 8-OHdG with a strong intensity (80%). All neoplastic cells were preferentially stained in only the cytoplasm (70.0%), but nuclear positivity was found in 30%, independent of the intensity. Based on the location in the cytoplasm and/or nucleus, tumors >4 cm showed a high frequency (95.5%) of 8-OHdG expression in only the cytoplasm, with a significant difference (p value 0.001). Additionally, overall survival was affected when immunoexpression was present in the cytoplasm and nucleus because all deaths were in this group were statistically significant (p value = 0.001). CONCLUSIONS: All tumors showed DNA oxidative damage, and 8-OHdG was preferentially expressed in the cytoplasm. This finding was associated with tumor size and, when present in the nucleus, might also be related to death.

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Objetivo: Describir resolución quirúrgica de teratoma de mediastino en dos tiempos que debuta en paciente con urgencia vital. Materiales y Métodos: Revisión de caso clínico y descripción retrospectiva del manejo quirúrgico realizado. Resultados: Estudio imagenológico evidenció tumor con contenido quístico que comprometía ambos hemitórax. Dado compromiso vital del paciente, se realiza quistocentesis descompresiva en pabellón, seguido de videotoracoscopía que demuestra origen mediastínico y quistectomía parcial por toracotomía. En un segundo tiempo quirúrgico, se reseca remanente vía esternotomía media. Discusión: Los teratomas mediastínicos son extremadamente infrecuentes, reportándose 44 casos en literatura mundial, sin registros a nivel nacional. Afecta a jóvenes sanos, la mayoría asintomáticos, siendo su hallazgo tardío e incidental. El compromiso de estructuras mediastínicas y de vía aérea pueden ocasionar riesgo vital. Conclusión: La descompresión perioperatoria del contenido quístico del teratoma fue fundamental para mantener fuera de riesgo vital al paciente durante el acto quirúrgico.

Objective: To describe the successful surgical resolution of a giant teratoma of the mediastinum that presents with a vital emergency. Clinical Case: Male patient, 30 years old, with no known history, consulted for a 1-year history of dyspnea on minimal exertion, associated with weight loss without dietary restriction. Imaging study showed tumor with cystic content that compromised both hemithorax. Given the patient's vital commitment, decompressive cystocentesis was performed, followed by video-assisted thoracoscopy that showed mediastinal origin and partial cystectomy by thoracotomy. In a second surgical time, resection of the remnant was performed via median sternotomy. Discussion: Mediastinal teratomas are extremely rare, reporting 44 cases in the world literature, with no national registry. They usually affect healthy young people, most of them asymptomatic and therefore, their discovery is late and incidental. In this case, due to the compression of noble structures, perioperative cystic decompression was essential. Conclusion: Perioperative decompression of the cystic content of the teratoma was essential to maintain stable hemodynamics and subsequent surgical resection.

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Resumen: Introducción: a medida que se invierte la pirámide poblacional, se viven vidas más largas y activas, se vuelven más frecuentes los pacientes geriátricos con trauma de alta energía; requiriendo más recursos, obteniéndose peores resultados, con más complicaciones perioperatorias, hacen a estas fracturas difíciles de manejar. Establecida la hipótesis de que la incidencia de las fracturas de pelvis y acetábulo, en el adulto mayor por trauma de alta energía, es superior a la reportada en la literatura mundial, se generó la pregunta de investigación: ¿Cuál es la incidencia de fracturas de pelvis y acetábulo por trauma de alta energía en el adulto mayor en un período de cinco años? Material y métodos: una vez obtenida la autorización del Comité de Ética, se realizó un estudio observacional de una cohorte retrospectiva, utilizando registros médicos, identificando la incidencia de estas fracturas, tratadas quirúrgicamente en nuestro hospital de III nivel, Clínica Las Vegas, Medellín, Colombia, del 1 de Julio de 2016 a 30 de Junio de 2021. Resultados: se calculó una incidencia acumulada de 1.95 nuevos casos por cada 100,000 personas-año, una prevalencia de 13.8%; resultando en una mayor incidencia y prevalencia, confirmándose nuestra hipótesis. Conclusión: el tratamiento debe orientarse a mejorar la calidad de vida con una fijación estable, identificación y tratamiento de lesiones asociadas, minimizando el riesgo de complicaciones mecánicas y priorizar el reforzamiento de medidas preventivas y a la mejora del comportamiento del rol masculino, que aparentemente, seguirán realizando actividades de riesgo a pesar de su edad.

Abstract: Introduction: as the population pyramid gets inverted, more active and longer lives are lived, geriatric patients with high energy trauma (HET) become more frequent; requiring more resources, getting worse results with more perioperative complications, coupled with a fragile state of health and osteopenia, make these fractures difficult to manage. With the hypothesis that the incidence of pelvic and acetabular fractures in the elderly due to HET is higher than that reported in the world literature, the research question was generated: What is the incidence of pelvic and acetabular fractures in the elderly due to HET, in a 5-year period? Material and methods: with the authorization of the Ethics Committee, an observational study of a retrospective cohort was carried out, using medical records, identifying the incidence of these fractures, surgically treated in our institution Clínica Las Vegas, Medellin, Colombia, a level III hospital, from July 1, 2016 to June 30, 2021. Results: a cumulative incidence of 1.95 new cases per 100,000 person-years was calculated, a prevalence of 13.8%; resulting in a higher incidence and prevalence, confirming our hypothesis. Conclusion: treatment should be aimed at improving quality of life with stable fixation, identification and treatment of associated injuries, minimizing the risk of mechanical complications and prioritizing the reinforcement of preventive measures, also in the improvement of male role behavior, whom, as it seems, will keep carrying out risky activities despite their age.

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Cocoa is one of the most important tropical fruits worldwide, its importance lies in its use in the food, cosmetic and pharmaceutical industries. Cocoa yield has been affected by different environmental, cultural and phytosanitary aspects. The emergence of new growing areas allows exploring the possibility of generating new economic and ecological systems that comply with current trends in organic farming. For them, pre-harvest practices such as pruning and soil fertilization are two necessary tools to control the productivity of cocoa agroecosystems. Therefore, the objective of this research was to analyses the implementation of pre-harvest techniques and the quality soil to increase the yield in a cocoa agroecosystem in an emerging zone in the Huasteca Potosina of Mexico. The work was carried out in an emerging zone in the cultivation of cocoa in three different zones delimited in 30 × 30 m. Thinning and pruning practices were carried out to keep the space clear and observe the influence on fruit yield. In addition, the quality of the soil was measured in terms of physical conditions and nutrient content. 25 kg/ha of nitrogen, 22 kg/ha of P2O5, 24 kg/ha of K2O and 4 kg/ha of magnesium were added following the recommendation of the fertilization laboratory. The physical properties of the pod were also analyzed, such as size, weight, number of grains and color. And some of the cocoa bean such as size, weight and hardness, all these parameters to measure the average yield of cocoa pods. The results show a clear influence of the soil quality and pre-harvest practices on the physical properties of the fruit and the total yield from 472.36 ± 52.01 to 520.06 ± 104.91 kg. However, other aspects are also modified, such as the increase in the size of the pod and the cocoa bean. Other aspects such as the color of the pod and the hardness of the grain do not present statistical difference. In conclusion, pre-harvest practices together with the application of fertilizers are factors that positively influence the yield of cocoa fruit. Some of the limitations of this research were the age of the plants and the local plant species.

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Approximately 23 Mt of plastics reaches the ocean each year, fragmented into microplastics (MP). MPs are widely dispersed in the sea, becoming deposited in sediments. MPs are considered carriers of pollutants such as heavy metals and polycyclic aromatic hydrocarbons and, when ingested by biota, pose a high health risk. This study determined metals and PAHs in sedimentary microplastics from the southern Gulf of Mexico (GOM). One hundred twenty-four sediment samples were collected, covering an area of 26,220 km2. The mean (±SD) of MPs in sediments was 16.46 ± 17.76 MPs/kg. The most abundant polymers were cellophane (CE), polyvinylidene fluoride (PVDF), polyethylene (PE), polyamides (PA), and nylon (NYL). A strong correlation (r: 0.83) was found between MP density and sediment depth. PA and PE were found near shorelines and PVDF near oil platforms. Aluminum, arsenic, and tin had the highest concentration (89.6 ± 94.6, 23.1 ± 70.3, and 19 ± 29.2 µg g-1, respectively), and acenaphthylene was the PAH with the highest concentration (3.4 ± 12.6 µg g-1). This study shows that MP with a higher density is found at greater depths, and this research is one of the first to cover a large area of the Gulf of Mexico.

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Intermittent ethanol consumption changes the neuronal activity of the orbitofrontal cortex (OFC) in rodents, which has been attributed to important participation in the development of addiction, particularly alcoholism. The OFC participates in gustatory sensory integration. However, it is unknown whether this region can encode chemosensory elements of oral ethanol administration independently of the consumption movement (orofacial motor response) when administered for the first time (naïve mice). To answer this question, we used a sedated mouse model and a temporary analysis protocol to register extracellular neuronal responses during the oral administration of ethanol. Our results show an increase in neuronal frequency (in the first 500 ms) when low (0.6, 1, and 2.1 M) and high (3.2, 4.3, and 8.6 M) concentrations of ethanol are orally administered. The modulatory effect of ethanol was observed from low and high concentrations and differed from the tastants. There was consistent neuronal activity independent of the concentration of ethanol. Our results demonstrate a sensory representation of oral ethanol stimulation in the OFC neurons of naïve mice under sedation.

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OBJECTIVES: The aim of this study was to investigate the psychometric properties of the Spanish version of the Stigma of Occupational Stress Scale for Doctors (SOSS-D) and the factors associated with Physician Burnout in Paraguay. METHODS: Participants included 747 Paraguayan healthcare workers, aged 24-77 years old, of both sexes. SOSS-D was translated into Spanish and validated through an exploratory and confirmatory factor analysis. Participants were also scored with the Oldenburg Burnout Inventory (OLBI), the CAGE questionnaire, and the stigma subscale of the Perceived Barriers to Psychological Treatment (PBPT) measure. RESULTS: Three factors had a raw eigenvalue greater than 1, and explained 61.7% of total variance. The confirmatory analysis confirmed that the scale is three-dimensional. The model adjustment was good, according to all fit indices. OLBI results indicate clinically significant disengagement in 85.9% and clinically significant exhaustion in 91.6% of participants. Of the 747 participants, 57.6% reported alcoholic beverage consumption and among those, 19.3% had problematic alcohol consumption according to the CAGE questionnaire. The correlation between SOSS-D and the stigma subscale of the PBPT was statistically significant (r = 0.245, p < 0.001). CONCLUSIONS: The Spanish version of the SOSS-D was found to have good psychometric properties and adequately reproduces the three-dimensional model of the original English version.

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ABSTRACT Zephyranthes citrina is an ornamental American bulbous plant used as an ornamental garden crop for the aesthetic qualities of its yellow perigonium. The objective of this work was to characterize the species by classical chromosome staining and fluorochrome banding. A sporophytic chromosome number of 2n=8x=48 chromosomes was observed, being the karyotypic formula 20 m + 26 sm + 2 st. Satellites were detected in the short arm of metacentric chromosomes 8, 9, 11 and 12, which colocalized with constitutive heterochromatin CMA+/DAPI-/0 bands. The karyotype comprised chromosome pairs with terminal constitutive heterochromatin bands that included satellites and heteromorphic clusters indicating that it is an allooctoploid. These results will be used as a tool for monitoring genetic improvement, in interspecific crosses and its progenies and in biotechnological procedures by in vitro culture.

RESUMEN Zephyranhtes citrina es una planta bulbosa americana, ornamental, utilizada en jardines por las cualidades estéticas de su perigonio amarillo. El objetivo de este trabajo fue caracterizar citogenéticamente la especie con tinción clásica convencional y bandeo cromosómico. Se observó un número cromosómico esporofítico de 2n=8x=48, siendo la fórmula cariotípica 20 m + 26 sm + 2st. Se detectaron satélites en el brazo corto de los cromosomas metacéntricos 8, 9, 11 y 12, que co-localizaron con bandas de heterocromatina constitutiva CMA+/DAPI-. El cariotipo comprendió pares de cromosomas con bandas de heterocromatina constitutivas terminales que incluyeron satélites y grupos heteromórficos que indican que es un alooctoploide. Estos resultados serán usados como herramientas en el monitoreo del mejoramiento genético, en análisis de cruzamientos interespecíficos y progenies y en procedimientos biotecnológicos de cultivo in vitro.

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Inherited retinal diseases (IRDs) represent a spectrum of clinically and genetically heterogeneous disorders. Our study describes an IRD patient carrying ABCA4 and USH2A pathogenic biallelic mutations as a result of paternal uniparental disomy (UPD) in chromosome 1. The proband is a 9-year-old girl born from non-consanguineous parents. Both parents were asymptomatic and denied family history of ocular disease. Clinical history and ophthalmologic examination of the proband were consistent with Stargardt disease. Whispered voice testing disclosed moderate hearing loss. Next-generation sequencing and Sanger sequencing identified pathogenic variants in ABCA4 (c.4926C>G and c.5044_5058del) and USH2A (c.2276G>T). All variants were present homozygously in DNA from the proband and heterozygously in DNA from the father. No variants were found in maternal DNA. Further analysis of single nucleotide polymorphisms confirmed paternal UPD of chromosome 1. This is the first known patient with confirmed UPD for two recessively mutated IRD genes. Our study expands on the genetic heterogeneity of IRDs and highlights the importance of UPD as a mechanism of autosomal recessive disease in non-consanguineous parents. Moreover, a long-term follow-up is essential for the identification of retinal features that may develop as a result of USH2A-related conditions.

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BACKGROUND: Ep-CAM, a transmembrane glycoprotein expressed in most epithelium in normal conditions, has diverse roles in these tissues, including in cell adhesion, proliferation, differentiation, cell cycle regulation, migration and intracellular signaling. It is also over-expressed in most malignant neoplasia, participating in the initiation, progression, and metastatic dissemination of the tumor. The expression and roles of this protein in oral neoplasia, particularly in odontogenic tumors, remain unestablished. The objective of this study consisted in analyzing the expression of this protein in ameloblastoma and tooth germ. MATERIAL AND METHODS: Ep-CAM (MOC-31) expression was evaluated by immunohistochemistry in tooth germs (TG) (n = 16) ameloblastomas (AM) (n = 60) and 2 ameloblastic carcinomas. Sections were visualized in their totality with an optical microscope, and positivity observed in cell membrane and cytoplasm was graded according to the following semi-quantitative scale: Neg, "essentially unstained", for negative sections or staining <5% of cells; + for staining of 5-50% of cells; ++ for staining >50% of cells. RESULTS: Most tooth germs expressed MOC-31 (81.3%), strong staining was observed both in the inner epithelium of the enamel organ and in the adjacent stellate reticulum. 16.7% of the AM cases showed MOC-31 expression, the immunoexpression expression was diffuse at the cytoplasmic and membrane level. The only two cases of ameloblastic carcinoma included were strong positive to MOC-31. No correlation was observed between protein expression and gender, age, clinical variants, or histological subtypes. CONCLUSIONS: Overexpression was found in TG and ameloblastic carcinoma compared to AM; further studies with different experimental strategies are suggested to clarify the biological significance of this finding.

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Armchair graphene nanoribbons, when forming a superlattice, can be classified into different topological phases, with or without edge states. By means of tight-binding and classical molecular dynamics (MD) simulations, we studied the electronic and mechanical properties of some of these superlattices. MD shows that fracture in modulated superlattices is brittle, as for unmodulated ribbons, and occurs at the thinner regions, with staggered superlattices achieving a larger fracture strain than inline superlattices. We found a general mechanism to induce a topological transition with strain, related to the electronic properties of each segment of the superlattice, and by studying the sublattice polarization we were able to characterize the transition and the response of these states to the strain. For the cases studied in detail here, the topological transition occurred at ∼3-5% strain, well below the fracture strain. The topological states of the superlattice - if present - are robust to strain even close to fracture. The topological transition was characterized by means of the sublattice polarization of the states.

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Plants are continuously exposed to stress conditions, such that they have developed sophisticated and elegant survival strategies, which are reflected in their phenotypic plasticity, priming capacity, and memory acquisition. Epigenetic mechanisms play a critical role in modulating gene expression and stress responses, allowing malleability, reversibility, stability, and heritability of favourable phenotypes to enhance plant performance. Considering the urgency to improve our agricultural system because of going impacting climate change, potential and sustainable strategies rely on the controlled use of eustressors, enhancing desired characteristics and yield and shaping stress tolerance in crops. However, for plant breeding purposes is necessary to focus on the use of eustressors capable of establishing stable epigenetic marks to generate a transgenerational memory to stimulate a priming state in plants to face the changing environment.

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Understanding the recovery of whale populations is critical for developing population-management and conservation strategies. The southern right whale (SRW) Eubalena australis was one of the baleen whale species that has experienced centuries of exploitation. We assess here for the first time the population dynamics of the SRW from the southwestern Atlantic Ocean at the regional level to measure numerically the effect of whaling and estimate the population trend and recovery level after depletion. We reconstructed the catch history of whaling for the period 1670-1973 by an extensive review of different literature sources and developed a Bayesian state-space model to estimate the demographic parameters. The population trajectory indicated that the pre-exploitation abundance was close to 58,000 individuals (median = 58,212; 95% CI = 33,329-100,920). The abundance dropped to its lowest abundance levels in the 1830s when fewer than 2,000 individuals remained. The current median population abundance was estimated at 4,742 whales (95% CI = 3,853-6,013), suggesting that the SRW population remains small relative to its pre-exploitation abundance (median depletion P2021 8.7%). We estimated that close to 36% of the SRW population visits the waters of the Península Valdés, the main breeding ground, every year. Our results provide insights into the severity of the whaling operation in the southwestern Atlantic along with the population´s response at low densities, thus contributing to understand the observed differences in population trends over the distributional range of the species worldwide.

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The transmission and transport properties of biperiodic graphene superlattices are studied theoretically. Special attention is paid to the so-called transparent states of biperiodic superlattices. A Dirac-like Hamiltonian is used to describe the charge carriers in graphene. The transfer matrix method and the Landauer-Büttiker formalism are implemented to obtain the transmittance and conductance, respectively. Similar results to those reported for Schrödinger electrons are obtained. However, in the case of Dirac electrons the splitted bands and the transparent states associated to the biperiodicity depend strongly on the angle of incidence as well as the character of the charge carriers. In fact, the dynamic of the splitted bands and transparent states is inverted for holes. The origin of transparent states is unveiled by obtaining an analytic expression for the transmittance. It is found that resonant transmission through single and double barriers gives rise to transparent states. Regarding the transport properties, it is possible to identify the fundamental changes caused by the biperiodicity. In particular, it is found a splitting, shifting, and diminishment of the conductance peaks with respect to the case of regular periodicity. This opens the door to corroborate experimentally the fundamental characteristics of biperiodic gated graphene superlattices through transport measurements.