The Sahel is a strip of land that begins in Mauritania and ends in Eritrea. It is approximately 5400 km long and varies in width from 100 to 1000 km. Based on different historical perspectives, the Sahel can be considered to encompass a total of five countries. Subsequently, other countries have been added that, due to their geographical and climatic characteristics, can be considered Sahelian. The Sahelian countries emerged after 1960, the year in which decolonization began, but also the instability that was initially triggered by military coups aimed at destabilizing power. Later, climatic instability, famine, political instability, terrorism, and other factors have also played a role. This essay focuses on analyzing the actions and current activities of certain actors in the Sahel.
Fine-scale habitat heterogeneity can generate marked short-distance variation in alpine-stream benthic macroinvertebrate assemblages, yet routine surveys often characterize a site using five Surber-net replicates collected within an approximately 100 m reach. We analyzed 99 quantitative samples collected at 10 m intervals along a 1 km reach of Qingbixi Stream on Cangshan Mountain, Dali, Yunnan, China, to relate taxonomic and functional diversity patterns to within-site sampling design. The samples contained 69 taxa and 15,034 individuals. Across 20 consecutive 50 m sections, turnover accounted for 70.9% of mean total pairwise taxonomic beta diversity, whereas nestedness accounted for 96.3% of mean total functional trait-state beta diversity. Taxonomic dissimilarity increased weakly but significantly with longitudinal distance. In ten simulated nominal 100 m sampling units, five spatial replicates detected an average of 82.9% of the locally observed taxon pool; completeness increased to 87.4% with six replicates and 94.6% with eight. These results support five replicates as a practical baseline for routine community characterization, while more intensive or microhabitat-stratified sampling is preferable when near-complete taxon detection or fine-scale beta-diversity assessment is required.
Radiotherapy (RT) remains a mainstay of cancer treatment, but its efficacy is limited by radioresistance and immunosuppression. Nucleic acid therapeutics, including siRNA, microRNA modulators, antisense oligonucleotides, aptamers, CpG oligodeoxynucleotides, and CRISPR systems, can remodel tumor responses at multiple levels. Nanotechnology enables their precise delivery, protection, and spatiotemporal activation. This review synthesizes recent advances in nucleic acid-enabled radiosensitization across four dimensions: (1) precise delivery via passive/active targeting and radiation-triggered release; (2) target selection from dominant-node inhibition to coordinated network regulation; (3) immune remodeling from checkpoint blockade to active immune instruction; and (4) multimodal integration where RT serves as a biological switch. We formally define programmable radio-nanomedicine as the co-design of nucleic acid cargo, carrier logic, activation trigger, and radiation schedule so that irradiation acts as a context-defining event. Translational barriers and a framework for next-generation design are discussed.
Evolutionary theory has been applied to help understand and predict parenting decisions. Parent-offspring conflict theory posits that conflicts between mothers and infants are inevitable because they share only half of their genes. A prediction drawn from this body of theory is that infants will typically benefit from later weaning than the timing that most benefits the mother, who has other arenas in which she must allocate her energy to ensure her family has enough resources, that her other children are cared for, and that she has energy to allocate to future pregnancies. This research tested whether the timing of weaning from breastmilk, measured as the maternally reported age at which their infant last breastfed, is consistent with expectations from parent-offspring conflict theory in the UK Millennium Cohort. Cox proportional hazards models predicting age last breastfed for the entire sample, including those never breastfed (adjusted model N = 15,825), and models for the subsample who ever breastfed were carried out (adjusted model N = 9678). Many of the results were consistent with predictions, including for variables that would not logically link to early weaning without thinking from an evolutionary perspective, such as preeclampsia (HR for weaning ever-breastfed infants = 1.08; 95% CI 1.00–1.17), and birthweight (HR for each 1 kg increment = 0.90; 95% CI 0.88–0.93). Older mothers weaned their infants later (HR for each year of maternal age = 0.94; 95% CI 0.92–0.97). The findings are discussed from evolutionary and public health perspectives as an example of the utility of evolutionary thinking for understanding health-related behaviours.
