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The Brauer-Weyl theorem (Brauer, Weyl. 1935 Am. J. Maths. 57, 425-449. (doi:10.2307/2371218)) states that the algebra of tensor products of spinors is isomorphic to the Clifford (geometric) algebra, in any number of space-time dimensions. The algebraic relation between fermions and bosons seen in the standard model agrees with the Brauer-Weyl theorem, but not with supersymmetry. It is commonly argued that string theory requires supersymmetry, on the grounds that non-supersymmetric bosonic string theory (i) does not admit fermions, and (ii) has an unstable tachyonic ground state. This paper rebuts those standard objections, pointing out that bosonic string theory admits fermions lying on a D-brane boundary of open strings, and that the open-string tachyon has all the properties of a Higgs field. The original 1970's formulation of bosonic string theory, re-envisaged as a theory of all the forces, not just the strong force, fits the standard model beautifully. This article is part of the theme issue 'Modern applications of geometric algebra'.
Biochar is a carbon-rich, porous substance produced from the thermal degradation process of carbon-based materials, like biomass and other solid waste, in an oxygen-deprived environment. The type of parent material and the conditions for processing are the principal factors in determining the properties of biochar. Because of its diverse physicochemical properties, biochar has gained growing attention over the decades as a cost-effective, sustainable, and emerging material with potential applications in energy, agriculture, and environmental sectors like wastewater treatment. Two different parent materials, such as wheat bran and maple leaf, were pyrolyzed at three different temperatures (300 °C, 500 °C, and 700 °C). The resultant biochar was analyzed for its adsorptive potential for different contaminants. All the tested physicochemical property values of the maple (Acer) leaf biochar were found to be higher than wheat (Triticum) bran biochar except bulk density and the dye absorption potential. Based on the biochar physiochemical properties, the pyrolysis temperature of 700 °C was found to be the best for pyrolyzing these biomasses. Irrespective of the biochar types, pH 2.0 with a residence time of 90 min outperformed with an initial dye concentration of 0.05 mg/mL and a biochar application rate of 50 mg/mL. Furthermore, MLBC exhibited higher oil adsorption potential in comparison with that of WBC. The addition of WBC and MLBC to the polymer beads increases their dye absorption competence; therefore, this biochar can be a potential means of water treatment.
Wildlife trade remains a major driver of accelerating global biodiversity loss, yet our knowledge of this trade remains fragmented. Our understanding of trade origins and flows is particularly poor, which prevents decision makers from identifying trends or assessing law enforcement efficacy. We assess the global dimensions of trade into the US across multiple taxonomic groups over two decades. We analyze geographic patterns to identify the origins of traded wildlife, including in endemic and threatened species. We identify major inconsistencies in provenance of wild species exports, as many traded species are labeled "wild," but not native to the country of export. The European Union represents a major source of arachnids and reptiles, many declared as wild. We further highlight a range of likely reporting errors, potential species laundering, and possible Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) violations. Counteracting biodiversity threats posed by the global wildlife trade requires better data, better standardization, and clear interventions to manage trade sustainably.
This study aimed to investigate the impact of the cost of financial inclusion services and perceived risk on the usage of these services among urban and rural populations in one of Africa's largest cities. Employing a cross-sectional design, data were collected from 453 participants, including 46.8
The unsustainable use of wildlife is a primary driver of global biodiversity loss. No comprehensive global dataset exists on what species are in trade, their geographic origins, and trade’s ultimate impacts, which limits our ability to sustainably manage trade. The United States is one of the world’s largest importers of wildlife, with trade data compiled in the US Law Enforcement Management Information System (LEMIS). The LEMIS provides the most comprehensive publicly accessible wildlife trade database of non-the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) listed species. In total, 21,097 species and over 2.85 billion individuals were traded over the past 22 y (2000-2022). When LEMIS data are combined with CITES records, the United States imported over 29,445 wild species, including over 50% of all globally described species in some taxonomic groups. For most taxa, around half of the individuals are declared as sourced from the wild. Although the LEMIS provides the only means to assess trade volumes for many taxa, without any associated data on most wild populations, it is impossible to assess the impact on biodiversity, sustainability of trade, or any potential risk of pest or pathogen spread. These insights underscore the considerable underestimation of trade and the urgent need for other countries to adopt similar mechanisms to accurately record trade.
