Number Of Consecutive Days Research Articles

Evaluation of CORDEX Regional Climate Models in Simulating Extreme Dry Spells in Southwest China

In recent decades, Southwest China (SWC) has experienced a series of severe and extensive droughts resulting in tremendous socioeconomic losses. The annual maximum dry spell length (AMDSL), which refers to the number of consecutive days without rainfall, or days with rainfall below a threshold, plays an important role in triggering drought. The main objective of this study is to provide a comparison of the capabilities of current regional climate models (RCMs) in simulating extreme dry spell characteristics in mountainous SWC. Five available RCM simulations utilized in the Coordinated Regional Climate Downscaling Experiment (CORDEX)-East Asia project over 1981 to 2005 were employed in this study; the RCMs being NIMR-HadGEM3, SNU-MM5, SNU-WRF, KNU-RegCM4 and YSU-RSM. Firstly, it was found that all RCMs reasonably simulate the main seasonality features of rainfall and dry days in SWC. Furthermore, besides YSU-RSM, the other four RCMs can accurately capture the spatial pattern of dry-day occurrence based on Taylor diagram diagnosis. Secondly, we assessed the performance of five RCMs to detect and reproduce the climatology and variability of the AMDSL. In general, RCMs simulate the spatial pattern of long-term mean and interannual variability of the AMDSL in SWC well. Based on Taylor diagram evaluation, NIMR-HadGEM3 was the best among 5 RCMs in simulating the AMDSL characteristics. Thirdly, the generalized extreme value (GEV) distribution is considered the most suitable model fitting the AMDSL in both observation and RCM experimental data in comparison to other three-parameter probabilistic models. Higher value centers of the scale parameter and the location parameter indicate a wider and amplified distribution of the AMDSL over the low-latitude highlands (LLH) region against other areas in Southwest China, which is consistent with spatial patterns of climatological AMDSL. In addition, sensitivity analysis of different thresholds for dry days show that the 1 mm threshold is suitable for this study and different threshold choices have little effect on simulation ability.

TERMAL COMFORT IN THE CITY OF BIJELJINA, FOR THE PERIOD 2009 – 2018 DEFINED BY WGBT

<p>In paper are presented results of bioclimatic model Wet bulbe globe temperature (WBGT) for the area of the city of Bijeljina, for the period of 10 years, from 2009 to 2018. The city is located in the north east part of Bosnia and Herzegovina and has a moderate continental climate. Results were obtained by calculation of meteorological data in software program Biklima 2.6. They show the presence of all five values defined with the WBGT index. Results differ in during the year, and seasons and have different number of days with the Unlimited (<18) being the most common value and Activity should be stopped (>30) the least presence. Some years have the high number of high values (over 30) and present a potential danger for a human organism if exposed to physical activities. Number of consecutive days with high value rises and presents danger for human organism.</p>

An artificial bee colony algorithm with variable neighborhood search and tabu list for long-term carpooling problem with time window

Carpooling is an effective sharing economy mode that can increase utilization ratio of vehicle and relieve traffic pressure in cities. A carpooling system needs to provide feasible car-sharing solution under the constraint on time window of each passenger. Moreover, fairness is important to a long-term car sharing problem. A person will not willing to share his/her car if he/she has more contribution than others. In this paper, a long-term carpooling problem with time window is investigated for a group of people with a common destination. In order to guarantee fairness, a person can be chosen as a driver only for a limited number of consecutive days. An artificial bee colony algorithm combining variable neighbor search and tabu list (ABC-VNSTL) are proposed. We designed five neighbor search strategies: one-swapping strategy, all-swapping strategy, moving strategy, passenger to driver strategy, and solution exchange strategy. The experiments results demonstrate that ABC-VNSTL can obtain better solution quality than other six algorithms in the literature. As the number of participants increases, the advantages of ABC-VNSTL increase. In addition, ABC-VNSTL algorithm is more efficient than the compared algorithms under the condition of achieving same solution quality.

The relationship between the number of consecutive days with heat stress and milk production of Holstein dairy cows raised in a humid continental climate

Heat stress is known to affect performance of dairy cows experiencing prolonged periods of high temperature and relative humidity. Less is known about its effects in cooler climates. The goals of the present study were to determine the prevalence of days susceptible to cause mild heat stress in dairy cows living in a humid continental climate and to investigate the relationship between the number of consecutive days of mild heat stress and milk, fat, protein, and lactose production. A 6-yr data set (2010-2015) containing 606,031 milk analysis records for 34,360 Holstein dairy cows at different parities was matched with the corresponding daily maximum temperature-humidity index. Exposure to heat stress conditions was divided into 5 categories corresponding to 0, 1 to 2, 3 to 4, 5 to 6, and 7 to 8 consecutive days before milk test date. On average, cows were exposed to heat stress conditions for 135.8 ± 5.9 d/yr in Southwest Quebec and 95.3 ± 10.2 d/yr in Eastern Quebec. Cows experiencing heat stress conditions produced on average less fat, protein, and energy-corrected milk and lower fat and protein concentrations. The decrease in milk fat reached 6% for category 7 to 8 exposure of cows in parity 3 or more. The association between exposure category and milk yield and lactose yield and concentration was weak. Heat stress lowered milk fat and protein production but had little effect on milk volume output. Further research is necessary to better understand the mechanism underlying the effects of sporadic low- to medium-intensity heat stress on dairy productivity.

The therapeutic role of emotion regulation and coping strategies during a stand-alone DBT Skills training program for alcohol use disorder and concurrent substance use disorders

Clinical trials on Dialectical Behavior Therapy Skills Training (DBT-ST) as a stand-alone intervention for alcohol use disorder (AUD) showed promising outcomes. Improvements in difficulties with emotion regulation (DER) played a mediating role on abstinence maintenance. However, the effect of DER, together with specific coping strategies, have not been considered yet in the treatment of clinical features associated to AUD and concurrent substance use disorders (CO-SUDs). The current study aims at investigating changes in the number of consecutive days of abstinence (CDA), severity of AUD and CO-SUDs (Shorter PROMIS Questionnaire; SPQ alcohol, prescription, illicit drugs subscale), DER (Difficulties in Emotion Regulation Scale; DERS) and coping strategies (DBT Way of Coping Checklist; DBT-WCCL) during a 3-month DBT-ST program for the treatment of AUD and CO-SUDs. Furthermore, four independent multiple parallel mediational models were estimated considering scores of CDA/SPQ, DERS and DBT-WCCL dimensions as dependent, independent and mediators variables respectively. One-hundred eight individuals with a primary diagnosis of AUD were consecutively admitted. The results showed significant and moderate to large improvements in CDA, severity of AUD, CO-SUDs and DER. The analyses detected significant improvements in the use of DBT Skills. The changes in DER predicted decreases in SPQ scores. The changes in DBT-WCCL scores were mediators of the previous relationships, considering SPQ alcohol and prescription drugs subscales. These findings support the implementation of DBT-ST as a stand-alone intervention for the treatment of AUD and CO-SUDs. DER together with coping strategies are relevant therapeutic mechanisms in the treatment of clinical features related to SUDs.

Mobility, temporality, and social reproduction: everyday rhythms of the ‘FIFO family’ in the Australian Mining Sector

The substantial use of Fly-in-Fly out (FIFO) work in the Australian mining sector involves a repeated cycle in which workers (mostly men) leave their homes to undertake a pre-determined number of consecutive days of work on (often remote) mine sites where they are also accommodated. They then spend a pre-determined number of days at home. This article examines how FIFO workers’ rhythms of physical absence and presence in family life shape the everyday mobilities and temporalities of their emplaced spouses as they undertake the work of social reproduction. It thus brings a gendered lens to the emergent literature examining interconnections of mobility and temporality. Drawing on in-depth interviews with twenty female partners of male FIFO mine workers, the analysis identifies the entangled ways in which this labour mobility profoundly reshapes women’s mobilities and interrelated experiences and organisation of social time. In particular, ‘the weekend’ emerges as a time of profound disjuncture for FIFO spouses who feel ‘out of kilter’ with conventional social rhythms associated with 9-5 work. The article thus elucidates contemporary intersections of changing formations of capitalism and the rhythms of social reproduction.

Evaluating the impact of rainfall and temperature on wheat dough strength in Western Australia

AbstractBackground and objectivesWestern Australian wheat farmers rely on the international market to sell their wheat. One advantage they have in the market place is Australia's reputation for good and reliable wheat quality. However, consecutive years of weaker‐than‐expected dough strength placed specific consistency concerns on Western Australian hard‐grained wheat exports. To investigate why weak dough strength occurred, a multi‐season set of data was compiled. It was made up of quality results from historical crop reports and breeder trials. Recycling of data was an efficient initial step to examine the problem, but to overcome limitations, modeled climate measurements and phenotype information needed to be combined with the quality data to allow mixed model statistics to be used for analysis of the unbalanced data.FindingsThe key findings were three climate measurements linked to weak dough properties as measured by extensograph maximum resistance. A negative relationship between dough strength and rainfall in the period 60 days after flowering, tested as the percentage of total growing season rainfall, was found. Two temperature‐related measurements were identified as having a positive relationship with dough strength. These were the number of consecutive days that had a maximum temperature of ≥28°C and mean daily temperature range occurring during the 60‐day period after flowering.ConclusionsThe combined impact of moisture and temperature levels during the post‐flowering period on wheat dough strength builds on the previous understanding of high temperatures changing dough strength.Significance and noveltyThe recycling of data was a useful first step in understanding a complex issue, and the results provide a reference guide for further research into understanding the interaction between a changing growing environment and important wheat quality parameters.

A paired trial comparing mononuclear cell collection in two machines for further inactivation through an inline or offline extracorporeal photopheresis procedure.

Extracorporeal photopheresis (ECP) is an effective treatment. However, protocols differ widely, and some questions, such as the number of cells to be collected or the number of ECP treatment days per treatment cycle, are still unsolved. The aim of this study was to compare a multistep (offline) (Spectra Optia and Macogenic G2) against an integrated (inline) ECP system (Therakos Cellex system) with respect to mononuclear cell (MNC) collection. The number and quality parameters of the MNC products collected were evaluated together with some machine parameters, such as collection time. Comparisons were made through paired sample analysis with the t test. Fourteen patients underwent 15 double-paired procedures using both ECP protocols. The average MNC collected in the multistep procedure was 77.4 × 108 , four times more than in the integrated procedure (18.5 × 108 ). MNC purity (84.4% vs. 63.8%) and enrichment (27.9 vs. 5.9) in the product collected were also higher in the multistep procedure. The whole ECP time was higher in the multistep than in the integrated procedure (272 vs. 106 min), but the calculated time to collect 25 × 108 MNCs in the multistep was shorter compared with the one-step procedure (77.8 vs. 172 min). All these differences between the two protocols were statistically significant. These two ECP protocols are different with respect to MNC collection and length of procedure. Some unresolved questions, such as the better MNC dose to inactivate or the number of consecutive days that ECP should be performed for optimal clinical efficacy, require further review.

Does the Time Between Scoring Sessions Impact Scoring Accuracy? An Evaluation of Constructed‐Response Essay Responses on theGRE® General Test

This report investigates whether the time between scoring sessions has an influence on operational and nonoperational scoring accuracy. The study evaluates raters' scoring accuracy on constructed‐response essay responses for theGRE® General Test. Binomial linear mixed‐effect models are presented that evaluate how the effect of various predictors, such as time spent scoring each response, days in a scoring gap, and number of consecutive days of scoring, relate to scoring accuracy. Results suggest that for operational scoring, the number of days in a scoring gap has a negative influence on performance. The findings, as well as other results from the models, are discussed in the context of cognitive influences on knowledge and skill retention.

Duration of topical therapy in the maintenance of atopic dermatitis remission in pediatric age.

Topical corticosteroids (TCS) are the first-choice treatment for atopic dermatitis (AD) flares. In literature there are clear advice about the potency, dosage and frequency of application of TCS, but there are no shared indications about duration of the treatment during a flare. The aim of the study is to demonstrate if the use of a steroid cream for less than or 5 days, could be equal or more effective than the application for more than 5 days during a flare episode, in keeping a remission state of AD. The study population (N.=122) was selected according to the following inclusion criteria: at least one specialist allergological and dermatological examination in the period November 2015 to February 2017, age between 1 and 11 years; mild to moderate atopic dermatitis. All patients were given a standardized telephone questionnaire, which concerns on multiple aspects: parents' self-reported perceptions of the severity of their child's condition; actual use of emollients, moisturizers and steroid creams; number of consecutive days of using of topical steroid cream during an exacerbation of AD; average number of AD exacerbations per month in the last year; total number of AD exacerbations in the last year. Data from 96 patients was examined. We classified three groups of patients from data collected: group 1 (N.=40): use of TCS for ≤5 consecutive days during an exacerbation event of AD; group 2 (N.=12): use of TCS for >5 consecutive days during an exacerbation event of AD; group 3 (N.=44): nonuse of TCS or use of TCS with a different posology. We found a further subgroup in group 3 (3a, N.=27) with patients using only emollient crème in AD management. In group 1, 27 patients (67.5%) did not show a good AD control; on the contrary, 13 patients (27.5%) reported a good AD control. In group 2, 4 patients (25%) did not show a good AD control; on the contrary, 8 patients (75%) reported a good AD control. By comparing the data obtained in the presence of good AD control, the difference between the percentages obtained was found to be statistically significant (P=0.034). The results obtained show that a therapeutic pattern based on the use of TCS for a duration of more than 5 consecutive days during an episode of AD exacerbation is more efficient than the proposed alternative therapeutic scheme in the maintenance of AD remission.

\u201cWe\u2019ll check vital signs only till we finish the school\u201d: experiences of student nurses regarding intra-semester clinical placement in Ghana

BackgroundClinical practicum is an integral part of nursing education because it provides students with opportunities to perform nursing care and practice specific nursing tasks. In Ghana, little is known about the experiences of baccalaureate student nurses with regard to intra-semester clinical practicum. This study therefore, explored perceptions, challenges, and how the intra-semester clinical practicum affects the learning process of student nurses in a private university in Ghana.MethodsExploratory descriptive phenomenological design was used. Nine in-depth interviews and three focus group discussions were conducted for baccalaureate student nurses in their second, third and fourth years of study. Only those who have attended intra-semester clinical practicum for at least two semesters in the course of their study were recruited. Purposive sampling technique was used to select the participants. The sample size was based on data saturation, however, a total of 33 participants were recruited. Data was analysed using content analysis technique.ResultsThe findings show that baccalaureate student nurses perceive the intra-semester clinical practicum as beneficial. It affords the opportunity to translate theoretical knowledge into practice concurrently. However, students recounted their stressful experiences during the clinical period which negatively affected their academic work. Additionally, staff nurses assigned the students to do menial jobs instead of appropriate nursing tasks.ConclusionsA review of the “block” method in which students will go to clinicals for a stipulated number of consecutive days in a month and then resume lectures, is worth considering.

Potential impact of 1.5 °C and 2 °C global warming on consecutive dry and wet days over West Africa

We examine the impact of +1.5 °C and +2 °C global warming levels above pre-industrial levels on consecutive dry days (CDD) and consecutive wet days (CWD), two key indicators for extreme precipitation and seasonal drought. This is done using climate projections from a multi-model ensemble of 25 regional climate model (RCM) simulations. The RCMs take boundary conditions from ten global climate models (GCMs) under the RCP8.5 scenario. We define CDD as the maximum number of consecutive days with rainfall amount less than 1 mm and CWD as the maximum number of consecutive days with rainfall amount more than 1 mm. The differences in model representations of the change in CDD and CWD, at 1.5 °C and 2 °C global warming, and based on the control period 1971−2000 are reported. The models agree on a noticeable response to both 1.5 °C and 2 °C warming for each index. Enhanced warming results in a reduction in mean rainfall across the region. More than 80% of ensemble members agree that CDD will increase over the Guinea Coast, in tandem with a projected decrease in CWD at both 1.5 °C and 2 °C global warming levels. These projected changes may influence already fragile ecosystems and agriculture in the region, both of which are strongly affected by mean rainfall and the length of wet and dry periods.

Functional dimorphic enantiostyly in monomorphic enantiostylous species of the subtribe Cassiinae (Fabaceae-Caesalpinioideae).

Monomorphic enantiostylous species produce flowers with a displacement of the style to the left (L) or right (R) on the same individual, and may exhibit different dynamics for the production of these floral types, which may influence levels of selfing. We investigated the production dynamics of L and R floral types in seven species and a variety of monomorphic enantiostylous species of the genera Senna and Chamaecrista. Our hypothesis was that most species present similar proportions of floral morphs each day. Individuals were classified daily over a period of 7days according to the functional status, i.e. the proportion of floral morphs as functionally L, R or reciprocal (REC, i.e. similar proportions of the two floral morphs), and also according to the number of consecutive days in which they exhibited the same functional status. All species presented low daily flower production. Most species had individuals classified as functionally R, L and REC, and tend to repeat the same functional status over a few days, although they may change functional status during the flowering period. All species exhibited individuals that were classified as functionally reciprocal when both the daily and total number of flowers produced over 7days was considered. The occurrence of different functional status has not yet been reported in the literature for enantiostylous species. The distinct strategies observed in the dynamics of floral morph production seemed likely to minimise geitonogamy and to favour cross-pollination between individuals (xenogamy).

Monitoring and Modelling Bio-Physical Parameters for Hypoxia Hazard in a Coastal Sand Pit

Management of coastal areas requires monitoring and modeling of the anthropogenic drivers and the bio-physical processes affecting water quality. To assess the range of hydrographic conditions controlling oxygen distribution in the bottom layers of sand pits, a multi-year oceanographic survey has been conducted in a coastal area with several extraction pits. Hydrographic data including profiles of temperature, salinity and oxygen were collected and related to local wind conditions and circulation. Moreover, 1D and 3D high-resolution non-hydrostatic ocean models were used to describe turbulent mixing regimes and to obtain the range of wind speeds for which the critical anoxic conditions may occur. It is shown that wind speed appears to control the dynamics of oxygen concentrations, with oxygen depleted zones developing in a short time in low wind speed conditions. Moreover, the depth and the shape of the extraction pit contribute to decrease the mixing of the bottom layers and increase the water retention in the hole increasing the output and the persistence of oxygen depleted zones in the excavated area. The results of the numerical simulations show that the risk of hypoxia at the bottom of the sand pits is associated with higher temperatures and wind speed lower than 5 m/s, which is not infrequent during the summer season. However, the number of consecutive days of oxygen depletion can be considered lower than the danger threshold level assumed in the literature.

Red warning for air pollution in China: Exploring residents' perceptions of the first two red warnings in Beijing

Air pollution early warnings have been issued in China to mitigate the effects of high pollution days. Public perceptions and views about early warning signals can affect individual behaviors and play a major role in the public's response to air pollution risks. This study examined public attitudes and responses to the first two red warnings for air pollution in Beijing in 2015. An online survey was sent out, and 664 respondents (response rate = 90%) provided their perspectives on the red warnings. Descriptive statistics, sign tests and binary logit models were used to analyze the data. More than half of the respondents reported that their life and work were affected by the red warning in December 2015. In contrast to their perceptions about the second red warning period, the public thought that the first red warning should have been issued earlier and that the number of consecutive days of warnings should have been reduced. The respondents also recommended that instead of reducing the number of red warnings, the red warning emergency measures should be adjusted. Specifically, the public preferred the installation of air purifiers in schools rather than closing schools and strengthening road flushing and dust pollution controls over restrictions on driving. Data analyses were conducted to examine the affected groups and different groups' perceptions of the necessity of implementing emergency measures. The results indicated that men and more educated respondents were more likely to be affected by driving limitations, and men were less supportive of these limitations. The age and education of respondents were significantly negatively associated with the opinion that schools should be closed, whereas wealthier respondents were more supportive of school closings. The finding of a negative attitude among the public toward the first two red warnings may be used to help local governments modify protective measures and pollution mitigation initiatives to increase acceptance.

Analysis and modeling of cover crop emergence: Accuracy of a static model and the dynamic STICS soil-crop model

Abstract Cover crops are increasingly used in agriculture to provide a variety of ecosystem services (e.g. reducing nitrogen leaching, storing carbon in soils) during fallow periods, but it can be challenging to successfully establish them in summer, when water availability may be low. Thus, it is crucial to better quantify, understand and predict the emergence date of a variety of cover crops from multiple contexts in impact assessment studies. The objectives of this study were to 1) analyze variability in emergence dynamics among cover crops grown in fields, 2) identify variables that influence emergence the most and use them to develop a simple model to predict emergence date and 3) calibrate the STICS model to improve its predictions of cover crop emergence. STICS was chosen because it is a dynamic soil-plant model widely validated in the literature for simulating the production of cover crop services. We analyzed emergence dynamics of ten cover crop species sown under a variety of soil, climate and sowing conditions from 18 experimental sites across France. We developed and independently evaluated a static model based on these data to predict the number of days until emergence. We then calibrated STICS using the same data. Results revealed a mean emergence duration of 12 days for all species, but with high variability among experimental sites and years. The simple static model contained only three variables, with the number of consecutive days without significant water input after sowing the most significant. Overall, both the model and STICS predicted emergence date well in the calibration and validation datasets. Accurate prediction of soil moisture in the seedbed and soil water balance is a key factor to accurately predict cover crop emergence. Accurately predicting emergence of cover crops in crop models will help to assess the former’s ability to provide ecosystem services in cropping systems in current and future climates.

Associations between mortality and prolonged exposure to elevated particulate matter concentrations in East Asia

Previous epidemiological studies regarding mortality and particulate matter with an aerodynamic diameter of <10μm (PM10) have considered only absolute concentrations of PM10 as a risk factor. However, none have evaluated the durational effect of multi-day periods with high PM10 concentrations. To evaluate the durational effect (i.e., number of days) of high PM10 concentrations on mortality, we collected data regarding 3,662,749 deaths from 28 cities in Japan, South Korea, and China (1993–2009). Exposure was defined as consecutive days with daily PM10 concentrations ≥75μg/m3. A Poisson model was used with duration as the variable of interest, while controlling for daily PM10 concentrations, meteorological variables, seasonal trends, and day of the week. The increase in mortality risk for each additional consecutive day with PM10 concentrations ≥75μg/m3 was 0.68% in Japan (95% confidence interval [CI]: 0.35–1.01%), 0.48% in South Korea (95% CI: 0.30–0.66%), and 0.24% in China (95% CI: 0.14–0.33%). The annual average maximum number of consecutive days with high PM10 in Japan (2.40days), South Korea (6.96days), and China (42.26days) was associated with non-accidental death increases of 1.64% (95% CI: 1.31–1.98%), 3.37% (95% CI: 3.19–3.56%), and 10.43% (95% CI: 10.33–10.54%), respectively. These findings may facilitate the planning of public health interventions to minimize the health burden of air pollution.

Abstract 4541: Understanding the dose and schedule dependence of efficacy for the Wee1 inhibitor AZD1775 in xenograft and patient derived explant models by mathematical modelling

Abstract AZD1775 is a highly selective, small-molecule inhibitor of WEE1 being developed to treat patients with advanced solid tumors, as monotherapy and in combination with olaparib. Experimental Procedures Patient-derived explant (PDX) and xenografted models with a range of sensitivities to AZD1775 were tested for response to different doses and schedules of AZD1775. WEE1 inhibition was assessed by pCDK1 as a direct substrate of Wee1 and RRM2 as a surrogate of CDK2 activity. Concentration of AZD1775 in plasma was measured in the same animals. Mathematical models were developed to describe the relationship between drug exposure, biomarker modulation and resulting tumour growth inhibition. Results The PKPD relationship of both pCDK1 and RRM2 could be described by the mathematical model with significant delay between PK and RRM2 reduction due to this being a protein degradation event. Three factors influenced anti-tumour activity in the A427 xenograft and three TNBC PDX models, namely the AZD1775 dose, the number of consecutive days of dosing and the number of days between AZD1775 doses. The minimally effective preclinical dose with anti-tumour activity was 60 mg/kg od. TGI was seen to increase with increased days of consecutive AZD1775 dosing from 3 days on, such that a 5 days on/9 days off schedule was more efficacious than 3 days on/4 days off schedule for two weeks. A mathematical model successfully described this efficacy by using the predicted dose and schedule dependent reduction in pCDK1. Conclusions The insights from this predictive modelling informed the starting dose of 125mg BID AZD1775 on a 5 day on/9 day off schedule; with the clinical goal to optimize the days of consecutive AZD1775 dosing as well as the maximum tolerated dose. Citation Format: James W. Yates, Elaine Cadogan, Jennifer Hare, Adina Hughes, Urszula M. Polanska, Mark O'Connor, Susan E. Critchlow. Understanding the dose and schedule dependence of efficacy for the Wee1 inhibitor AZD1775 in xenograft and patient derived explant models by mathematical modelling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4541. doi:10.1158/1538-7445.AM2017-4541

Quantifying agricultural drought in tallgrass prairie region in the U.S. Southern Great Plains through analysis of a water-related vegetation index from MODIS images

Severe droughts in the Southern Great Plains (SGP: Kansas, Oklahoma, and Texas) in recent years have reduced the productivity of tallgrass prairie and resulted in substantial economic losses to the beef cattle industry in this region. Understanding spatial and temporal patterns of agricultural drought in the SGP can help ranchers to develop and implement drought mitigation strategies. In this study, the Land Surface Water Index (LSWI), calculated from the Moderate Resolution Imaging Spectroradiometer (MODIS) near infrared and shortwave infrared bands, was used to assess agricultural drought in the tallgrass prairie region of the SGP during 2000–2013. The number of consecutive days with LSWI <0 (DNLSWI) during the growing season was defined as the drought duration, which, was then used to identify and analyze frequency of summer drought and whole growing season drought (WGSD). The spatial pattern of DNLSWI was consistent with the east-to-west decreasing precipitation gradient across the SGP region. Summer drought duration as depicted by the DNLSWI in the western portion of the study area was around one and a half month. The occurrence of WGSD increased from one year in the east to up to six years in the west, demonstrating the susceptibility of the tallgrass prairie region to drought. In addition to the total amount of precipitation, its intra-annual distribution also played an important role in drought development. A comparison with other widely used national drought products, namely the Evaporative Stress Index (ESI), the Vegetation Drought Response Index (VegDRI), and the United States Drought Monitor (USDM), shows that LSWI-based drought has good agreement with ESI and USDM. Quantitative analyses indicate that LSWI-based drought agreed better with ESI in severe drought conditions than in moderate or pre-drought conditions. Severe drought periods characterized by the USDM also had low LSWI values. The areas affected by drought derived from the LSWI-based drought index were significantly correlated with hay production. As an indicator of vegetation water stress at moderate spatial resolution (∼500m), the LSWI has the potential to show drought conditions for an individual ranch and offer guidance for drought mitigation activities and livestock production.

Intensifying postfire weather and biological invasion drive species loss in a Mediterranean-type biodiversity hotspot

Prolonged periods of extreme heat or drought in the first year after fire affect the resilience and diversity of fire-dependent ecosystems by inhibiting seed germination or increasing mortality of seedlings and resprouting individuals. This interaction between weather and fire is of growing concern as climate changes, particularly in systems subject to stand-replacing crown fires, such as most Mediterranean-type ecosystems. We examined the longest running set of permanent vegetation plots in the Fynbos of South Africa (44 y), finding a significant decline in the diversity of plots driven by increasingly severe postfire summer weather events (number of consecutive days with high temperatures and no rain) and legacy effects of historical woody alien plant densities 30 y after clearing. Species that resprout after fire and/or have graminoid or herb growth forms were particularly affected by postfire weather, whereas all species were sensitive to invasive plants. Observed differences in the response of functional types to extreme postfire weather could drive major shifts in ecosystem structure and function such as altered fire behavior, hydrology, and carbon storage. An estimated 0.5 °C increase in maximum temperature tolerance of the species sets unique to each survey further suggests selection for species adapted to hotter conditions. Taken together, our results show climate change impacts on biodiversity in the hyperdiverse Cape Floristic Region and demonstrate an important interaction between extreme weather and disturbance by fire that may make flammable ecosystems particularly sensitive to climate change.