Arid and semiarid regions located in subtropical zones are projected to experience the most adverse impacts of climate change. During the warm season, observations and Intergovernmental Panel on ...Climate Change global climate models generally support a “wet gets wetter, dry gets drier” hypothesis in these regions, which acts to amplify the climatological transitions in the context of the annual cycle. In this study, we consider changes in U.S. early warm season precipitation in the observational record and regional climate model simulations driven by two “well‐performing” dynamically downscaled Coupled Model Intercomparison Project phase 3 (CMIP3) models (Hadley Centre Coupled Model, version 3 and Max Planck Institute (MPI) European Centre/Hamburg Model 5) that have a robust climatological representation of the North American Monsoon System (NAMS). Both observations and model results show amplification in historical seasonal transitions of temperature and precipitation associated with NAMS development, with Weather Research and Forecasting (WRF)‐MPI better representing the observed signal. Assuming the influence of remote Pacific sea surface temperature (SST) forcing associated with the El Niño–Southern Oscillation and Pacific Decadal Variability (ENSO‐PDV) on U.S. regional climate remains the same in the 21st century, similar extreme trends are also projected by WRF‐MPI for the next 30 years. A methodology is also developed to objectively analyze how climate change may be synergistically interacting with ENSO‐PDV variability during the early warm season. Our analysis suggests that interannual variability of warm season temperature and precipitation associated with Pacific SST forcing is becoming more extreme, and the signal is stronger in the observed record.
Key Points
Observed climate extremes are intensifying following SST natural variability
WRF forced by CMIP3 GCMs has limited ability to capture long‐term observe trend
RCM climate ensemble analysis must be objectively evaluated and weighted
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Intraspecific variation in snake venoms has been widely documented worldwide. However, there are few studies on this subject in Mexico. Venom characterization studies provide important data used to ...predict clinical syndromes, to evaluate the efficacy of antivenoms and, in some cases, to improve immunogenic mixtures in the production of antivenoms. In the present work, we evaluated the intraspecific venom variation of Crotalus basiliscus, a rattlesnake of medical importance and whose venom is used in the immunization of horses to produce one of the Mexican antivenoms. Our results demonstrate that there is variation in biological and biochemical activities among adult venoms and that there is an ontogenetic change from juvenile to adult venoms. Juvenile venoms were more lethal and had higher percentages of crotamine and crotoxin, while adult venoms had higher percentages of snake venom metalloproteases (SVMPs). Additionally, we documented crotoxin-like PLA2 variation in which specimens from Zacatecas, Sinaloa and Michoacán (except 1) lacked the neurotoxin, while the rest of the venoms had it. Finally, we evaluated the efficacy of three lots of Birmex antivenom and all three were able to neutralize the lethality of four representative venoms but were not able to neutralize crotamine. We also observed significant differences in the LD50 values neutralized per vial among the different lots. Based on these results, we recommend including venoms containing crotamine in the production of antivenom for a better immunogenic mixture and to improve the homogeneity of lots.
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•The venom of Crotalus basiliscus showed ontogenetic variation.•Crotamine was present in significant proportions in juvenile venom.•Crotoxin polymorphism was found in the venom of Crotalus basiliscus.•Mexican antivenom batches showed variations in neutralization.•The antivenom was not able to neutralize crotamine.
Key Contribution: We identified ontogenetic and geographic venom variation within Crotalus basiliscus based on enzymatic and biological activities and we describe polymorphism for crotoxin-like PLA2s. Venom neutralization efficacy of Birmex antivenom, for which C. basiliscus is an immunogen, varies among lots.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This investigation evaluates whether there is coherency in warm and cool season precipitation at the low-frequency scale that may be responsible for multi-year droughts in the US Southwest. This ...low-frequency climate variability at the decadal scale and longer is studied within the context of a twentieth-century reanalysis (20CR) and its dynamically-downscaled version (DD-20CR). A spectral domain matrix methods technique (Multiple-Taper-Method Singular Value Decomposition) is applied to these datasets to identify statistically significant spatiotemporal precipitation patterns for the cool (November–April) and warm (July–August) seasons. The low-frequency variability in the 20CR is evaluated by exploring global to continental-scale spatiotemporal variability in moisture flux convergence (MFC) to the occurrence of multiyear droughts and pluvials in Central America, as this region has a demonstrated anti-phase relationship in low-frequency climate variability with northern Mexico and the southwestern US By using the MFC in lieu of precipitation, this study reveals that the 20CR is able to resolve well the low-frequency, multiyear climate variability. In the context of the DD-20CR, multiyear droughts and pluvials in the southwestern US (in the early twentieth century) are significantly related to this low-frequency climate variability. The precipitation anomalies at these low-frequency timescales are in phase between the cool and warm seasons, consistent with the concept of dual-season drought as has been suggested in tree ring studies.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
During the North American monsoon global positioning system (GPS) Transect Experiment 2013, daily convective-permitting WRF simulations are performed in northwestern Mexico and the southern Arizona ...border region using the operational Global Forecast System (GFS) and North American Mesoscale Forecast System (NAM) models as lateral boundary forcing and initial conditions. Compared to GPS precipitable water vapor (PWV), the WRF simulations display a consistent moist bias in the initial specification of PWV leading to convection beginning 3–6 h early. Given appreciable observed rainfall, days are classified as strongly and weakly forced based only on the presence of an inverted trough (IV); gulf surges did not noticeably impact the development of mesoscale convective systems (MCSs) and related convection in northwestern Mexico. Strongly forced days display higher modeled precipitation forecast skill than weakly forced days in the slopes of the northern Sierra Madre Occidental (SMO) away from the crest, especially toward the west where MCSs account for the greatest proportion of all monsoon-related precipitation. A case study spanning 8–10 July 2013 illustrates two consecutive days when nearly identical MCSs evolved over northern Sonora. Although a salient MCS is simulated on the strongly forced day (9–10 July 2013) when an IV is approaching the core monsoon region, a simulated MCS is basically nonexistent on the weakly forced day (8–9 July 2013) when the IV is farther away. The greater sensitivity to the initial specification of PWV in the weakly forced day suggests that assimilation of GPS-derived PWV for these types of days may be of greatest value in improving model precipitation forecasts.
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BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Almost one-half of the annual precipitation in the southwestern United States occurs during the North American monsoon (NAM). Given favorable synoptic-scale conditions, organized monsoon ...thunderstorms may affect relatively large geographic areas. Through an objective analysis of atmospheric reanalysis and observational data, the dominant synoptic patterns associated with NAM extreme events are determined for the period from 1993 to 2010. Thermodynamically favorable extreme-weather-event days are selected on the basis of atmospheric instability and precipitable water vapor from Tucson, Arizona, rawinsonde data. The atmospheric circulation patterns at 500 hPa associated with the extreme events are objectively characterized using principal component analysis. The first two dominant modes of 500-hPa geopotential-height anomalies of the severe-weather-event days correspond to type-I and type-II severe-weather-event patterns previously subjectively identified by Maddox et al. These patterns reflect a positioning of the monsoon ridge to the north and east or north and west, respectively, from its position in the "Four Corners" region during the period of the climatological maximum of monsoon precipitation from mid-July to mid-August. An hourly radar–gauge precipitation product shows evidence of organized, westward-propagating convection in Arizona during the type-I and type-II severe weather events. This new methodological approach for objectively identifying severe weather events may be easily adapted to inform operational forecasting or analysis of gridded climate data.
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BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Asthma, a common chronic airway disorder, affects an estimated 25 million persons in the United States and 330 million persons worldwide. Although many asthma patient registries exist, the ability to ...link and compare data across registries is hindered by a lack of harmonization in the outcome measures collected by each registry.
The purpose of this project was to develop a minimum set of patient- and provider-relevant standardized outcome measures that could be collected in asthma patient registries and clinical practice.
Asthma registries were identified through multiple sources and invited to join the workgroup and submit outcome measures. Additional measures were identified through literature searches and reviews of quality measures and consensus statements. Outcome measures were categorized by using the Agency for Healthcare Research and Quality's supported Outcome Measures Framework. A minimum set of broadly relevant measures was identified. Measure definitions were harmonized through in-person and virtual meetings.
Forty-six outcome measures, including those identified from 13 registries, were curated and harmonized into a minimum set of 21 measures in the Outcome Measures Framework categories of survival, clinical response, events of interest, patient-reported outcomes, resource utilization, and experience of care. The harmonized definitions build on existing consensus statements and are appropriate for adult and pediatric patients.
The harmonized measures represent a minimum set of outcomes that are relevant in asthma research and clinical practice. Routine and consistent collection of these measures in registries and other systems would support creation of a national research infrastructure to efficiently address new questions and improve patient management and outcomes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Pierce’s disease of grapevine and citrus huanglongbing are caused by the bacterial pathogens Xylella fastidiosa and Candidatus Liberibacter asiaticus (CLas), respectively. Both pathogens reside ...within the plant vascular system, occluding water and nutrient transport, leading to a decrease in productivity and fruit marketability and ultimately death of their hosts. Field observations of apparently healthy plants in disease-affected vineyards and groves led to the hypothesis that natural products from endophytes may inhibit these bacterial pathogens. Previously, we showed that the natural product radicinin from Cochliobolus sp. inhibits X. fastidiosa. Herein we describe a chemical synthesis of deoxyradicinin and establish it as an inhibitor of both X. fastidiosa and Liberibacter crescens, a culturable surrogate for CLas. The key to this three-step route is a zinc-mediated enolate C-acylation, which allows for direct introduction of the propenyl side chain without extraneous redox manipulations.
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IJS, KILJ, NUK, PNG, UL, UM
This paper examines the ability of the Weather Research and Forecasting model forecast to simulate moisture and precipitation during the North American Monsoon GPS Hydrometeorological Network field ...campaign that took place in 2017. A convective-permitting model configuration performs daily weather forecast simulations for northwestern Mexico and southwestern United States. Model precipitable water vapor (PWV) exhibits wet biases greater than 0.5 mm at the initial forecast hour, and its diurnal cycle is out of phase with time, compared to observations. As a result, the model initiates and terminates precipitation earlier than the satellite and rain gauge measurements, underestimates the westward propagation of the convective systems, and exhibits relatively low forecast skills on the days where strong synoptic-scale forcing features are absent. Sensitivity analysis shows that model PWV in the domain is sensitive to changes in initial PWV at coastal sites, whereas the model precipitation and moisture flux convergence (QCONV) are sensitive to changes in initial PWV at the mountainous sites. Improving the initial physical states, such as PWV, potentially increases the forecast skills.
Spatial patterns of interannual variability in US precipitation and their forcing mechanisms are very different between the cool and warm seasons, as determined by the recent observational record. In ...this work, the dominant continental scale patterns of warm season precipitation variability, in the form of the standardized precipitation index (SPI), are related to their large‐scale atmospheric teleconnection forcing patterns. To account for intraseasonal differences in atmospheric teleconnection patterns, the 2‐month SPI is considered for the separate periods of early, June–July (JJ), and late, August–September (AS), periods, as well as the 6‐month SPI for the cool season (November–April). Rotated empirical orthogonal function analysis and canonical correlation analysis are applied to determine the dominant spatial modes of SPI, their relationship to large‐scale teleconnection patterns, and their possible forcing mechanisms, as seen in anomalies of 500‐mb geopotential height, sea surface temperature (SST), and outgoing longwave radiation (OLR). Two dominant quasi‐stationary Rossby wavetrain teleconnections appear to govern US warm season precipitation variability: (1) a mode that reflects the well‐known out‐of‐phase relationship in summer precipitation between the central United States and southwest, which is related to Pacific SST forcing in early summer and Indian monsoon convection in later summer, and (2) Two phases of the Circumglobal Teleconnection pattern that are more related to precipitation variability in the south central and eastern United States The southwest United States region relating to the variability of the North American Monsoon is considered within the continental scale variability patterns associated with the warm season. This work is a subset of a larger project to determine if tree‐ring records from the southwest United States are reliable proxies for extending the warm season climate record. It also provides a benchmark for assessing how US warm season climate patterns may be assessed in regional climate models used for seasonal forecast or climate change projection purposes.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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