Current evidence suggests that Indigenous farmers in the North American Southwest began canal irrigation in the second millennium BC, marking an important change in food production technology. Early canal systems are preserved in alluvial floodplains of the US-Mexico Borderlands region, tend to be deeply buried, and can appear as natural fluvial features. Here I discuss some of the challenges in identifying early canals and associated fields and present case studies from the Santa Cruz River in southern Arizona where buried channels dating as early as 1600–1400 BC were likely human constructed. These small channels share several stratigraphic properties and are consistent with hypotheses of early canal irrigation practiced by small family groups reliant on mixed farming and foraging. Through time, irrigation canal systems expanded in size, resulting in increased labor investment, sedentism, and productivity and facilitating the development of larger irrigation communities. Stratigraphic and geomorphic properties of early canal systems thus far identified along the Santa Cruz River provide a framework for identifying potential early canal evidence in other fine-grained floodplains of the Southwest, thereby improving our understanding of Indigenous agricultural intensification.

Between 1930 and 1980, the U.S. census bureau moved from using a Mexican as a racial category to Hispanic as an ethnicity. In between, the census bureau tried multiple ways to count Mexican Americans, Spanish Americans, or Latinos. Each measure the bureau tried ran headlong into differing subnational understandings of ethnicity, race, and Americanness. To understand Latino racial formation in this critical period, then, requires looking to the states. This paper explores the census counts in the southwest states between 1930 and 1970. Contextualizing these numbers with a history of differing state policies on language, marriage, and political inclusion reveals the importance of state-specific understandings of race and identity to understanding United States racial formation.

This article examines large-scale spatial and temporal patterns in the agricultural demographic transition (ADT) of Mesoamerica and southwestern North America (“the Southwest”). An analysis of published settlement and subsistence data suggests that the prolonged ADTs of these regions involved two successive eras of rapid population growth. Although both periods of growth were fueled by the introduction or development of more productive domesticates, they had distinctive demographic and social consequences. The first phase of the ADT occurred only in a scattering of favorable regions, between 1900 and 1000 BC in Mesoamerica and 1200 BC–AD 400 in the Southwest. Its demographic consequences were modest because it was underwritten by still rather unproductive maize. During this phase, increased population was confined mainly to a few agricultural heartlands, whereas surrounding regions remained sparsely populated. The second phase of the ADT was more dramatic in the spatial scale of its impact. This “high productivity” phase unfolded between 1000 and 200 BC in Mesoamerica and AD 500–1300 in the Southwest, and it was fueled by more productive maize varieties and improving agricultural technologies. It was accompanied by sweeping social, economic, and political changes in both regions.

African animal trypanosomiasis (AAT) affects the livestock of 12.3 million Somalis and constrains their development and wellbeing. There is missing data on AAT in the country after the civil war of the 1990s. Therefore, this study has aimed to assess the prevalence of Trypanosoma spp. in 614 blood samples from cattle (n = 202), goats (n = 206) and sheep (n = 206) in Afgoye and Jowhar districts, Somalia using parasitological and molecular methods. Twenty-one out of 614 (3.4%; 95% CI: 2.1–5.2%) and 101/614 (16.4%; 95% CI: 13.6–19.6%) ruminants were positive for Trypanosoma spp. by buffy coat technique (BCT) and internal transcribed spacer 1 (ITS1)-polymerase chain reaction (PCR), respectively. Using ITS1-PCR, the highest prevalence was observed in cattle (23.8%; 95% CI: 18.4–30.1%) followed by goats (17.5%; 95% CI: 12.9–23.3%) and sheep (8.3%; 95% CI: 5.1–12.9%). A total of 74/101 (73.3%; 95% CI: 63.5–81.6%) ruminants were shown coinfection with at least two Trypanosome species. The four T. brucei-positive samples have tested negative for T. b. rhodesiense, by the human-serum-resistance-associated-PCR. Trypanosoma evansi, T. godfreyi, T. vivax, T. brucei, T. simiae and T. congolense were the Trypanosoma species found in this study. This is the first study on the molecular detection of Trypanosoma sp. in ruminants in Somalia. Further investigations and control measures are needed to manage Trypanosomiasis spreading in the country. Studies should also focus on the detection of T. b. rhodesiense in the country.