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Concept: Phoenix, Arizona


Abstract. Entomologic investigations were conducted during an intense outbreak of West Nile virus (WNV) disease in Maricopa County, Arizona during July 31-August 9, 2010. The investigations compared the East Valley outbreak area, and a demographically similar control area in northwestern metropolitan Phoenix where no human cases were reported. Five mosquito species were identified in each area, and species composition was similar in both areas. Significantly more Culex quinquefasciatus females were collected by gravid traps at Outbreak sites (22.2 per trap night) than at control sites (8.9 per trap night), indicating higher Cx. quinquefasciatus abundance in the outbreak area. Twenty-eight WNV TaqMan reverse transcription-polymerase chain reaction-positive mosquito pools were identified, including 24 of Cx. quinquefasciatus, 3 of Psorophora columbiae, and 1 of Culex sp. However, Cx. quinquefasciatus WNV infection rates did not differ between outbreak and control sites. At outbreak sites, 30 of 39 engorged Cx. quinquefasciatus had fed on birds, 8 of 39 on humans, and 1 of 39 on a lizard. At control sites, 20 of 20 identified blood meals were from birds. Data suggest that Cx. quinquefasciatus was the primary enzootic and epidemic vector of this outbreak. The most important parameters in the outbreak were vector abundance and blood meal analysis, which suggested more frequent contact between Cx. quinquefasciatus and human hosts in the outbreak area compared with the control area.

Concepts: Epidemiology, Mosquito, Dengue fever, West Nile virus, Centers for Disease Control and Prevention, DEET, Arizona, Phoenix, Arizona


In many places of the world, a Neolithic Demographic Transition (NDT) is visible as a several-hundred-year period of increased birth rates coupled with stable mortality rates, resulting in dramatic population growth that is eventually curtailed by increased mortality. Similar processes can be reconstructed in particular detail for the North American Southwest, revealing an anomalously long and spatially variable NDT. Irrigation-dependent societies experienced relatively low birth rates but were quick to achieve a high degree of sociopolitical complexity, whereas societies dependent on dry or rainfed farming experienced higher birth rates but less initial sociopolitical complexity. Low birth rates after A.D. 1200 mark the beginning of the decline of the Hohokam. Overall in the Southwest, birth rates increased slowly from 1100 B.C. to A.D. 500, and remained at high levels with some fluctuation until decreasing rapidly beginning A.D. 1300. Life expectancy at 15 increased slowly from 900 B.C. to A.D. 700, and then increased rapidly for 200 y before fluctuating and then declining after A.D. 1400. Life expectancy at birth, on the other hand, generally declined from 1100 B.C. to A.D. 1100/1200, before rebounding. Farmers took two millennia (∼1100 B.C. to ∼A.D. 1000) to reach the carrying capacity of the agricultural niche in the Southwest.

Concepts: Mortality rate, Demography, Population, Life expectancy, Native Americans in the United States, Demographic economics, World population, Phoenix, Arizona


Worldwide, coastal communities' ethnomedicinal knowledge has been sporadically recorded and poorly understood. Based on the ethnomedicinal knowledge of the Seri people; a hunting-gathering and fishing society of Northwestern Mexico, this study assesses a) the biological richness of Seri ethnomedicinal knowledge, b) the fidelity level of Seri remedies, and c) the association between gender, age, years of formal schooling and Seri ethnomedicinal knowledge.

Concepts: Sociology, Desert, Phoenix, Arizona, Mojave Desert, Sonoran Desert, Indigenous peoples in Mexico


We assessed transboundary wildfire exposure among federal, state, and private lands and 447 communities in the state of Arizona, southwestern United States. The study quantified the relative magnitude of transboundary (incoming, outgoing) versus nontransboundary (i.e., self-burning) wildfire exposure based on land tenure or community of the simulated ignition and the resulting fire perimeter. We developed and described several new metrics to quantify and map transboundary exposure. We found that incoming transboundary fire accounted for 37% of the total area burned on large parcels of federal and state lands, whereas 63% of the area burned was burned by ignitions within the parcel. However, substantial parcel to parcel variation was observed for all land tenures for all metrics. We found that incoming transboundary fire accounted for 66% of the total area burned within communities versus 34% of the area burned by self-burning ignitions. Of the total area burned within communities, private lands contributed the largest proportion (36.7%), followed by national forests (19.5%), and state lands (15.4%). On average seven land tenures contributed wildfire to individual communities. Annual wildfire exposure to structures was highest for wildfires ignited on state and national forest land, followed by tribal, private, and BLM. We mapped community firesheds, that is, the area where ignitions can spawn fires that can burn into communities, and estimated that they covered 7.7 million ha, or 26% of the state of Arizona. Our methods address gaps in existing wildfire risk assessments, and their implementation can help reduce fragmentation in governance systems and inefficiencies in risk planning.

Concepts: United States, U.S. state, State, Hispanic and Latino Americans, Arizona, New Mexico, Phoenix, Arizona, United States National Forest


Objectives To demonstrate the feasibility of partnering fire department personnel and home visiting nurses to increase the number of low-income homes protected by smoke alarms. Methods During a regularly scheduled home visit, nurses at the Nurse-Family Partnership of Maricopa County (NFP) informed their clients about an opportunity to have smoke alarms installed in their homes for free. For interested families, nurses sent a referral to the Phoenix Fire Department (PFD), scheduled an appointment, and accompanied the PFD volunteers during the installation. During the appointment, PFD personnel installed alarms and provided safety education. Clients completed a follow-up survey 1-3 months after the installation visit. In-depth interviews were completed with key informants from NFP and PFD to solicit feedback on the program. Results Fifty-two smoke alarm installation visits were completed. Before the fire department arrived, 55% of homes had no working smoke alarm. Almost all (94%) homes received at least one new smoke alarm, and every home had at least one working smoke alarm at the end of the fire department visit. At follow-up, all homes maintained at least one working smoke alarm. Members from both organizations were enthusiastic about, and supportive of the project. NFP nurses appreciated the skill and knowledge of the firefighters; PFD representatives noted that the nurses' relationships with clients made it easier for them to gain access to families who are often described as “hard-to-reach”. Conclusions Partnering home visiting nurses and fire departments can be successful to increase the number of vulnerable homes with smoke alarms.

Concepts: Smoke, Alarm, Firefighter, Home, Smoke detector, Alarms, Fire department, Phoenix, Arizona


The global spread of multi-drug resistant Gram negative has led to the return of colistin for treating severe infections. Recently, different plasmid-mediated genes conferring resistance to this drug were described and reported worldwide. International committees (EUCAST/CLSI) re-evaluated inconsistencies surrounding colistin antimicrobial susceptibility testing (AST), concluding that broth microdilution (BMD) should serve as the reference method for AST. The development of an accurate, reproducible commercial test based on BMD is therefore highly desirable. The SensiTest™ Colistin (STC), a BMD-based compact 4-test panel, containing the lyophilized antibiotic in 7 two-fold dilutions (0,25 - 16 μg/ml) was here compared with the EUCAST-CLSI standard reference method (BMD), and for some isolates, with the automated system Phoenix 100™ (PHX). A total of 353 bacterial strains were evaluated by two different laboratories; 137 isolates were resistant to colistin (19 intrinsically, 83 harboring the mcr-1 gene). Essential agreement (EA) between STC and BMD was obtained for 339 out of the 353 strains tested (96,0%). The overall categorical agreement was obtained for 349 out of the 353 strains analyzed (98,9%). Two major errors (MEs, 0,93%) and two very major errors (VMEs, 1,46%) were documented. STC appeared as a simple but highly reliable test, with a good reproducibility even with panels stored at room temperature or at 35°C. Moreover, STC showed a good performance on strains carrying the mcr-1 gene, with a 98,8% EA. As secondary endpoint of our study, VMEs for PHX were documented for 6 isolates (10%).

Concepts: Scientific method, Gene, Bacteria, Antibiotic resistance, Reproducibility, Gram staining, Phoenix, Arizona, Standard Reference Method


As recreational visitation to the Sonoran Desert increases, the concern of scientists, managers and advocates who manage its natural resources deepens. Although many studies have been conducted on trampling of undisturbed vegetation and the effects of trails on adjacent plant and soil communities, little such research has been conducted in the arid southwest. We sampled nine 450-m trail segments with different visitation levels in Scottsdale’s McDowell Sonoran Preserve over three years to understand the effects of visitation on soil erosion, trailside soil crusts and plant communities. Soil crust was reduced by 27-34% near medium and high use trails (an estimated peak rate of 13-70 visitors per hour) compared with control plots, but there was less than 1% reduction near low use trails (peak rate of two to four visitors per hour). We did not detect soil erosion in the center 80% of the trampled area of any of the trails. The number of perennial plant species dropped by less than one plant species on average, but perennial plant cover decreased by 7.5% in trailside plots compared with control plots 6 m off-trail. At the current levels of visitation, the primary management focus should be keeping people on the originally constructed trail tread surface to reduce impact to adjacent soil crusts.

Concepts: Plant, Surface runoff, Perennial plant, Geomorphology, Phoenix, Arizona, Desertification, Mojave Desert, Sonoran Desert


Anthropogenic water sources (AWS) are developed water sources used as a management tool for desert wildlife species. Studies documenting the effects of AWS are often focused on game species; whereas, the effects on non-target wildlife are less understood. We used live trapping techniques to investigate rodent abundance, biomass, and diversity metrics near AWS and paired control sites; we sampled vegetation to determine rodent-habitat associations in the Sauceda Mountains of the Sonoran Desert in Arizona. A total of 370 individual mammals representing three genera and eight species were captured in 4,800 trap nights from winter 2011 to spring 2012. A multi-response permutation procedure was used to identify differences in small mammal community abundance and biomass by season and treatment. Rodent abundance, biomass, and richness were greater at AWS compared to control sites. Patterns of abundance and biomass were driven by the desert pocket mouse (Chaetodipus penicillatus) which was the most common capture and two times more numerous at AWS compared to controls. Vegetation characteristics, explored using principal components analysis, were similar between AWS and controls. Two species that prefer vegetation structure, Bailey’s pocket mouse (C. baileyi) and white-throated woodrat (Neotoma albigula), had greater abundances and biomass near AWS and were associated with habitat having high cactus density. Although small mammals do not drink free-water, perhaps higher abundances of some species of desert rodents at AWS could be related to artificial structure associated with construction or other resources. Compared to the 30-year average of precipitation for the area, the period of our study occurred during a dry winter. During dry periods, perhaps AWS provide resources to rodents related to moisture.

Concepts: Species, Precipitation, Mammal, Rodent, Desert, Phoenix, Arizona, Mojave Desert, Sonoran Desert


Numerous mechanisms may allow species to coexist. We tested for frequency-dependent predation, a mechanism predicted by theory and established as a foraging behavior for many types of animals. Our field test included multiple prey species exposed in situ to multiple predator species and individuals to determine whether the prey species experienced predation patterns that were frequency-dependent. The prey were seeds of three species of Sonoran Desert winter annual plants while the predator species were a guild of nocturnal seed foraging heteromyid and murid rodents that co-occur naturally in the same community as the desert annuals at Tumamoc Hill near Tucson. Seeds of one species were much preferred over the other two. Nonetheless, we found the net effect of rodent foraging to be positively frequency-dependent (the preference for each species is higher when it is common than when it is uncommon) as has been previously hypothesized. This frequency-dependent predation should function as a species coexistence promoting mechanism in concert with the storage effect which has been previously demonstrated for this system. This article is protected by copyright. All rights reserved.

Concepts: Plant, Predation, Annual plant, Mouse, Optimal foraging theory, Desert, Phoenix, Arizona, Sonoran Desert


Aridisols are the dominant soil type in drylands, which occupy one-third of Earth’s terrestrial surface. We examined controls on biogeographical patterns of Aridisol prokaryotic (bacterial and archaeal) communities at a regional scale by comparing communities from 100 Aridisols throughout the southwestern United States using high-throughput sequencing of the 16S rRNA gene. We found that microbial communities differed among global biomes and deserts of the Southwest. Differences among biomes were driven by differences in taxonomic identities, whereas differences among deserts of the Southwest were driven by differences in relative sequence abundance. Desert communities were dominated by Actinobacteria, Proteobacteria and Crenarchaeota, supporting the notion of a core set of abundant taxa in desert soils. Our findings contrast with studies showing little taxonomic overlap at the OTU level (97% sequence similarity) across large spatial scales, as we found ∼90% of taxa in at least two of the three deserts. Geographic distance structured prokaryotic communities indirectly through the influence of climate and soil properties. Structural equation modeling suggests that climate exerts a stronger influence than soil properties in shaping the composition of Aridisol microbial communities, with annual heat moisture index (an aridity metric) being the strongest climate driver. Annual heat moisture index was associated with decreased microbial diversity and richness. If the Desert Southwest becomes hotter and drier as predicted, these findings suggest that prokaryotic diversity and richness in Aridisols will decline.

Concepts: Archaea, Bacteria, Microbiology, Earth, Precipitation, 16S ribosomal RNA, Colorado, Phoenix, Arizona