University of Havana

We aim to deduce analytic expressions for the homogenised coefficients that describe the mechanical behaviour of a uniaxially fibre‐reinforced composite material consisting of two solid constituents undergoing inelastic distortions, one representing the extracellular matrix, and the other representing the inclusions that model the fibres. While our work is mathematical in nature, our underlying goal is to explore questions related to biology, as biological systems, such as soft and hard tissues, can change their properties in response to various internal and external factors. One of our key motivations is to tackle the computational complexities involved in determining the effective, macroscopic properties of such biological systems. This requires addressing the interactions across different scales of the so‐called cell and homogenised problems. To achieve this, we begin by formulating the governing equations that describe the dynamics of the composite's constituents, provided by the balance of linear momentum and the law for the evolution of the inelastic distortions. We then employ the asymptotic homogenisation technique to derive the individual cell‐level problems and the homogenised macroscopic equations. This process also yields expressions for effective coefficients that capture the overall behaviour of the composite material. In a first step towards our investigations and to illustrate the capabilities of our approach, we consider the case in which the composite under study possesses a fibre‐reinforced structure. Together with additional hypotheses, we concentrate on the calculation of the effective properties using complex variable methods. Finally, after obtaining general formulae, we focus on providing numerical results.

The election of 2024 in the US determined who would oversee making policies to cope with increasing domestic and external demands driving structural adjustment to a new context. The evolution of knowledge capitalism implies a redistribution of core processes in the world-system and a relative loss of power by the US, coupled with changes in the hierarchy of structuring processes in all dimensions of social life. It implies the collapse of earlier configurations and a complex array of grievances and fears. This generates discontent and de-legitimation of formal and informal institutions that articulated prior configurations.

The objective of this study was to determine the presence of Drechslera/Helminthosporium in the air of a wheat crop in the NW Iberian Peninsula and its relationship with meteorological variables. Research was conducted in A Limia, Ourense, during the wheat growing seasons from 2021 to 2023. The Lanzoni VPPS-2010 spore trap was used to collect the spores, which were identified by optical microscopy. The phenological stages of the wheat crop were classified according to the BBCH scale, and the spore concentrations in each phenophase were analyzed. Meteorological variables were provided by a meteorological station located near the spore trap. In 2021, monitoring was done for 94 days, in 2022 for 89 days and in 2023 for 78 days. Spores were detected during most phenological stages, mainly during 11–20 h. Temperature and sunshine hours were the variables that positively influenced the variations in Drechslera/Helminthosporium concentrations in the air in 2021 and 2023, while in 2022, relative humidity, rainfall and leaf moisture were the factors that had the most influence. The maximum temperature and leaf moisture of the previous days were the variables that best predicted the concentrations of these spores for 2022. This is the first investigation in Spain that reports the presence of the sporal type Drechslera/Helminthosporium in the air during all phenological stages of wheat cultivation, and provides useful information for the development of strategies to prevent the diseases they cause.

We aim to understand better the significance of retained primitive reflexes (RPRs) and examine the effect of RPRs in children, adolescents, and adults, focusing on autism spectrum disorder (ASD) and other neurodevelopmental conditions, as well as examining a basis for future treatment alternatives. We included a history section to better recognise the way that the scientific and medical communities have studied and understood the importance of RPRs. We review findings indicating that aspects of these disorders are related to the presence of functional disconnectivities related to a cortical maturational effect on neuronal networks. The cortical maturational delay within specific networks may lead to enhanced growth and maturation in other networks, resulting in asynchronous development and inconsistency in functional skills. There has been reported an overconnectivity of short-range, more immature connections and an underconnectivity of long-range, more mature connectivities. We review the relationship between motor and cognitive impairments and RPRs. A crucial conclusion will be that inhibiting these RPRs is representative of treatment targets.

Eleutherodactylus bartonsmithi is a critically endangered Cuban frog with an extremely restricted range, found only in the evergreen forest surrounding the Yumurí River Canyon, Baracoa, Guantánamo. The region has undergone significant disturbances due to Hurricane Matthew and the construction of a 4.5 km road, yet the impact of these disturbances on the species remains unknown. This study provides the first data on the species’ occurrence, vocal activity, distribution, and relative abundance, using eco-acoustic methods to assess habitat health following these natural and anthropogenic disturbances. Over 15 days of semi-continuous acoustic recordings were collected in February, June, and October 2022 from five sites within the species’ type locality. Analysis of acoustic indices indicated that, despite the road’s impact, sites with greater soundscape complexity and heterogeneity were those closest to the road. These sites also showed the highest relative abundance of the species. The highest acoustic activity of E. bartonsmithi was detected in October, when environmental conditions appeared most favorable. Across all sampled months, peak daily activity occurred from 05:00 to 07:00 h, coinciding with the most intense male choruses. These findings provide essential baseline data for the development of conservation strategies aimed at protecting E. bartonsmithi and its habitat. Additionally, these efforts could benefit other endangered Cuban anurans in the region, such as E. bresslerae and E. etheridgei.

Assessing conservation status and pursuing applicable management priorities for marine megafauna across multiple scales pose significant challenges. Because marine turtles exemplify these challenges, the IUCN Marine Turtle Specialist Group (MTSG) developed the ‘conservation priorities portfolio’ (CPP) framework in 2011 to evaluate population risk and threats for regional management units (RMUs). Here, the MTSG updated the 2011 CPP framework through an inclusive assessment process. Expert elicitation results involving 145 individuals from 50 countries suggested that marine turtle conservation status appears to be improving, but significant challenges remain. Since the previous assessment, long-term abundance trends increased on average, and threat impact scores improved for nearly twice as many RMUs (53%) as worsened (28%) (≥ 10% threshold for changes in numeric scores). While expert-assessed threat impacts have generally decreased, fisheries bycatch remains the highest scored threat across regions and species. Risk-Threat categories improved for most (54%) RMUs. Over 40% of RMUs were scored as Low Risk-Low Threats, eight of which were green turtles Chelonia mydas. Less than 20% of RMUs were scored as High Risk-High Threats, four of which were leatherback turtles Dermochelys coriacea. Most High Risk-High Threats RMUs were in the Pacific Ocean, while most Low Risk-Low Threats RMUs were in the Atlantic Ocean. Eleven RMUs were evaluated as critical data needs. Our results—also provided through an interactive data dashboard—underscore the importance of context-specific planning to effectively target limited conservation resources. Future assessments should further prioritize inclusion of under-represented topics, researchers, and regions to better address multi-faceted conservation challenges.

This article explores the intersection of right-wing populism and US immigration policies, highlighting historical roots, key legislation, and contemporary implications. From early twentieth-century restrictions like the Johnson-Reed Act to the economic crises shaping migration debates, populism has consistently influenced policy. In the twenty-first century, its role intensified, particularly during the 2016, 2020, and 2024 elections. The rise of Trumpism underscores both continuity and rupture, amplifying restrictive policies and polarizing discourse. This analysis examines the impact of US populism on migration trends, highlighting how various immigration legislation reflect shifting policies and their broader implications for border management and international relations.

Cuba and the United States (US) have had a long and complex relationship in which the Cuban revolution had a huge impact. Successive US administrations have sought regime change, and their actions have impacted on the daily life of ordinary Cubans. Consequently, Cubans pay attention to presidential elections in US. Who is the next president and what to expect? Taking into consideration Trump’s record and the composition of his foreign policy team, it is safe to anticipate a negative impact on the bilateral relations. Political and diplomatic confrontation as well as a reinforcement of unilateral coercive measures will prevail.

Cadmium sulfide is a valuable material for solar cells, photovoltaic, and radiation detectors. It is thus important to evaluate the material damage mechanisms and damage threshold in response to irradiation....

Official statistics constitute an essential public good, ensuring that the different actors in the government and society have the necessary knowledge to make informed decisions, implement policy actions, and measure their results. In this context, all components of the national statistical system should have sufficient capacities to address the increasing demands of statistical information and to implement new methods for its production and dissemination. Cuba is currently undertaking a modernisation process of its National Statistical System, under the leadership of the National Statistics and Information Office, which aims to tackle the critical aspects affecting the Other Entities Producing Official Statistics, as a result of the quality limitations of the statistical processes they implement. The objective of this work is to elaborate a statistical process management model for the Other Entities Producing Official Statistics, which should take into account the organisational and methodological principles that derive from national and international standards. The implementation of this statistical process management model can contribute to the fulfilment of the UN Fundamental Principles of Official Statistics.

Starch is the main chemical component of corn grain (Zea mays) grain with values between 72% and 85%. The physicochemical and technological properties of corn starch are closely related to its variety and structure. The objective of this research was then to characterize and analyze the physicochemical properties of starch obtained from corn var. P-7928. The degree of hydrolysis of native and gelatinized starch was calculated. The water holding capacity (WHC) was evaluated in 2% starch suspensions heated to 60, 70, 80, and 90 ° C. The water solubility index was determined by gravimetry. Starch from corn var. P-7928 has a syneresis of 45% in 15 days; the degree of hydrolysis was 21% and that of the gelatinized starch was 98%. The maximum WHC was 50% at a temperature of 90°C and the water solubility index was 20 at 60°C. According to the results found, the starch of this variety has good properties compared to commercial starches on the market, making this variety a potential candidate for the obtaining of starch.

A high level quantum mechanical study has been performed to explore the structural rearrangement and relative stability of the XH4+ (X = C, Si, Ge) radical cations at their X̃2T2 ground electronic states. All the stationary points located on the lowest adiabatic sheet of the Jahn–Teller (JT) split X̃2T2 state are fully optimized and characterized by performing harmonic vibrational frequency calculations. Five JT distorted stationary points with D2d(B22), C3v(A12), C2v(B22), and Cs(A′2) symmetries are located on the CH4+ ground state potential energy surface (PES), whereas four such structures are found on each of the SiH4+ and GeH4+ PESs. While the C2v(B22) isomer is found to be a global minimum and the Cs(A′2) one as a transition state for CH4+, the nature of them is reversed for SiH4+ and GeH4+. In particular, the Cs(A′2) stationary points are now global minima for the latter pair of radical cations, and C2v(B22) represents the transition state. Attempts are being made to understand such inconsistent findings via a combination of JT and epikernel principles. The barriers between equivalent C2v(B22) global minimum structures for CH4+ are found to be low, and thus CH4+ undergoes rapid interconversion along cyclic exchange of three hydrogen atoms via Cs transition state. The general features of the ground state PESs of SiH4+ and GeH4+ are similar. The pseudorotation between the Cs lowest energy structures undergoes along SiH2 and GeH2 wagging motions via C2v(B22) transition state for SiH4+ and GeH4+, respectively.

Currently, acne therapy relies not only on specific drugs but also on complementary treatments, such as dermocosmetics. Several studies have reported the use of chitosan and alginate in scaffolds for drug delivery systems. These materials can be loaded with a product that exhibits anti-acne properties such as silk sericin, a protein with antioxidant, photoprotective, and moisturizing properties. Therefore, this study proposes the development of a chitosan/alginate scaffold, loaded with sericin, to serve as a dermocosmetic platform complementing the pharmacological treatment of acne. The moisture content of the alginate and chitosan was determined as 14.7 and 21%, respectively; the ash content, which is similar for both polymers, was approximately 5%. The employed chitosan had a deacetylation degree of 82%, as determined by infrared spectrometry and corroborated by potentiometry. This technique was also used to determine the mannuronic/guluronic ratio of the alginate [M/G = 1.3] and confirm the identity of each one of the polymers in the raw materials and the resulting scaffolds. The molecular weights of alginate, chitosan, and sericin were 85, 5.1, and 57.4 kDa, respectively. The pH [6.31] and total protein concentration of the sericin solution [c(SER) = 6.1 mg/mL] were determined using UV-visible spectrophotometry. Swelling and release studies indicated that, although there were varying degrees of cross-linking and certain variables to control, the mechanism that defines the nature of both processes (otherwise complementary) is the relaxation of the polymer chains.

Background SARS-CoV-2 and other viruses rely on the protease function of the TMPRSS2 protein to invade host cells. Despite cancer patients often experience poorer outcomes following SARS-CoV-2 infection, the role of TMPRSS2 in different cancer types has not yet been analyzed in detail. Therefore, the aim of the study was to determine the expression, function and clinical relevance of TMPRSS2 in tumors. Methods Publicly accessible RNA sequencing data from tumors, adjacent tissues and whole blood samples of COVID-19 patients as well as data from human tumor epithelial and endothelial cells infected with SARS-CoV-2 were analyzed for TMPRSS2 expression and correlated to the expression of immune-relevant genes and clinical parameters. In vitro models of cells transfected with TMPRSS2 (TMPRSS2high), siTMPRSS2 or mock controls (TMPRSS2low cells) were analyzed by qPCR, flow cytometry, ELISA and Western blot for the expression of immune response-relevant molecules. Co-cultures of TMPRSS2 model systems with blood peripheral mononuclear cells were employed to evaluate immune cell migration, cytotoxicity and cytokine release. Results Higher expression levels of TMPRSS2 were found in blood from patients infected with SARS-CoV-2, while TMPRSS2 expression levels significantly varied between the tumor types analyzed. TMPRSS2high tumor cells exhibit increased activity of the interferon (IFN) signal pathway accompanied by an increased expression of class I human leukocyte antigens (HLA-I) and programmed cell death ligand 1 (PD-L1) elevated interleukin 6 (IL-6) secretion and reduced NK cell-mediated cytotoxicity compared to TMPRSS2low mock controls. Treatment with a Janus kinase (JAK) 2 inhibitor or TMPRSS2-specific siRNA decreased TMPRSS2 expression. Co-cultures of the in vitro TMPRSS2 models with peripheral blood mononuclear cells in the presence of the immune checkpoint inhibitor nivolumab resulted in a significantly increased migration and infiltration of immune cells towards TMPRSS2high cells and a reduced release of the innate immunity-related cytokines CCL2 and CCL3. Conclusions This study provides novel insights into the role of TMPRSS2 in various tumor systems and the impact of SARS-CoV-2 infection on the host immunogenicity via the activation of immune-relevant pathways. These findings were linked to the efficacy of immune checkpoint inhibitor therapy, offering a potential alternative strategy to mitigate the severity of COVID-19.