Kern County Research Articles

Modelling the impact of oil price changes and investment decisions on construction wages in the U.S.

The U.S. construction industry has been known to employ workers without a college education and provide adequate compensation make ends meet. Today, job quality in the industry has deteriorated to a level where wages are too low, causing workers to rely on U.S. safety net programs. This may be exacerbated by oil price changes, especially in regions where the oil industry is a significant driver of the economy. In this paper, we investigate the effects of oil price dynamics on real wages in the construction industry. A non-linear ARDL and TAR model are used for the empirical exercise which focusses on six top oil producing counties in the U.S. Long-run findings indicate that a 10% increase in oil price increases construction wages by 1.4, 1.2 and 9.3% in Kern, Weld and McKenzie Counties, respectively. Short run estimates indicate that a positive shock to oil prices increases wages in McKenzie County, North Dakota. Results from the TAR model show that the impact of an expansionary monetary policy to increase investment – and accordingly, increase wages – is diluted when oil prices are below the low oil price threshold.

Earthquake Response of Arch Dams including Hydrodynamic effect using ABAQUS

A simple arch dam [1] is analyzed to find responses due to an earthquake, including the hydrodynamic effect of the reservoir water. The simple arch shape dam was modeled as a monolith structure, assuming the linear behavior of dam concrete. The arch dam is modeled with finite elements. The hydrodynamic effect is considered as an added mass of water adhered to the dam’s upstream surface [2]. Natural frequencies and mode shapes are computed for the dam without water and the dam with water. Time history analysis of the dam is performed for the Kern County earthquake (1952), Taft component 111 acceleration time history. The added mass of water is calculated according to the Kuo 1982 [2] research paper. Various results containing Cantilever stresses, arch stresses, and deflections are shown and plotted. Analyses are performed with the help of the Abaqus Software.

Assessing the water security effectiveness of integrated river basin management: Comparative case study analysis for lesson-drawing

Climate change, population growth, over-abstraction and industrial pollution are impacting the security of water resources globally, raising policy relevant questions over the optimality of institutional arrangements for their management. This paper seeks to add to this debate by assessing the effectiveness of integrated river basin management for achieving water security, in two case studies: the Konya Closed Basin in Turkey, and the Kern County Subbasin in California. A modified Institutional Analysis and Development (IAD) framework is employed to compare biophysical, community and governance factors in these cases to show how they influence water security, measured through a dedicated set of indicators. Results show that differentials in water security outcomes between the cases is, in part, related to how organizational rules compel actor participation in planning processes and the degree of coherence between multi-level institutions, particularly inter-agency collaboration. On this basis, the paper then engages with the public policy theory literature on lesson-drawing to assess the potential for policy learning for these specific contexts and other countries. The significance of the study therefore relates to its holistic integration of governance analysis, comparative case design and lesson-drawing for informing future river basin institutional design in achieving effective water security.

Global Sensitivity Analysis of a Coupled Hydro-Economic Model and Groundwater Restriction Assessment

Assessing impacts on coupled food-water systems that may emerge from water policies, changes in economic drivers and crop productivity requires an understanding of dominant uncertainties. This paper assesses how a candidate groundwater pumping restriction and crop prices, crop yields, surface water price, electricity price, and parametric uncertainties shape economic and groundwater performance metrics from a coupled hydro-economic model (HEM) through a diagnostic global sensitivity analysis (GSA). The HEM used in this study integrates a groundwater depth response, modeled by an Artificial Neural Network (ANN), into a calibrated Positive Mathematical Programming (PMP) agricultural production model. Results show that in addition to a groundwater pumping restriction, performance metrics are highly sensitive to prices and yields of perennial tree crops. These sensitivities become salient during dry years when there is a higher reliance on groundwater. Furthermore, results indicate that performing a GSA for two different water baseline conditions used to calibrate the production model, dry and wet, result in different sensitivity indices magnitudes and factor prioritization. Diagnostic GSA results are used to understand key factors that affect the performance of a groundwater pumping restriction policy. This research is applied to the Wheeler Ridge-Maricopa Water Storage District located in Kern County, California, region reliant on groundwater and vulnerable to surface water shortages.

Neonicotinoid exposure in Tricolored Blackbirds (Agelaius tricolor)

There is increasing awareness of the negative ecological and environmental effects of widespread use of pesticides on the landscape. Spillover or drift of pesticides from agricultural areas has been shown to impact species health, reproduction, and trophic dynamics through both direct and indirect mechanisms. Neonicotinoid insecticides are associated with observed declines of insectivorous and grassland birds, and these environmental pollutants are a significant conservation concern for many species that have experienced past or current population declines. Due to the high efficacy of these modern insecticides in depressing local insect populations, insectivorous birds can be negatively impacted by a pesticide-mediated reduction in food supply. Neonicotinoids may act synergistically with other stressors, such as habitat loss, to exacerbate threats to species or population viability. The Tricolored Blackbird is an insectivorous grassland bird of conservation concern in California, USA. Due to the high association of this species with agricultural habitats, we sought to quantify the amount of neonicotinoid residues in Tricolored Blackbird carcasses as a first step in assessing how this species may be impacted by pesticides. Out of 85 salvaged carcasses sampled (N = 24 adults, N = 3 fledglings, and N = 58 nestlings), only two contained detectable levels of target compounds. These were an adult and one nestling that contained clothianidin residue (40 ppb and 7 ppb, respectively); both of these birds were salvaged from breeding colonies associated with dairy farms in Kern County, California. We suggest that further work is needed to assess neonicotinoid exposure of Tricolored Blackbirds in dairy-associated breeding colonies.

Public perception of oilfield produced water: The case of California's Central Valley

Oilfield Produced Water (OPW) has been identified as a viable solution to mitigate water scarcity in California‘s Central Valley. However, consumer perception on the use of OPW outside of the oil and gas industry remains unknown and poses a hurdle for large-scale adoption. This paper, based on 134 randomly selected residents of Kern County (California‘s largest oil-producing county and top agricultural region), examined attitudes towards OPW reuse. In the survey, more than half (52.3%) of participants said that they have heard about oilfield-produced water and other reclaimed waters. Findings also suggest that participants mostly preferred rain and stormwater, and interestingly scored OPW higher than industrial and black waters for irrigation purposes. Around 67% of the participants supported the use of oilfield-produced water for irrigating crops. Younger people (18–29 years) expressed greater concern about using OPW compared to the older residents. Given the drought conditions in Central Valley, policymakers might need to focus on a circular economy and mandate the use of OPW in Central Valley considering that this region‘s economy lies at the nexus of the O&G and agriculture industries.

Two new alkali-sink specialist species of Paruroctonus Werner 1934 (Scorpiones, Vaejovidae) from central California.

Herein we describe two new species of Paruroctonus (Werner 1934) from California: Paruroctonussoda sp. nov. from the Soda Lake playa at the center of the Carrizo Plain in San Luis Obispo county and Paruroctonusconclusus sp. nov. from the Koehn Lake playa in the Mojave Desert of Kern County. They can be differentiated from other Paruroctonus by a combination of morphological features including deeply scalloped pedipalp fingers in males, specific patterns of fuscous pigmentation, unique setal counts, and unique morphometric ratios. They can also be separated from one another by the latter three characters. Photographs of a large selection of live scorpions are provided, including detailed images and figures of many morphological features. Their distributions, habitats, and ecologies are discussed; and important steps towards their conservation are described.

Understanding perinatal patient’s health preferences and patient-provider relationships to prevent congenital syphilis in California and Louisiana

BackgroundCongenital syphilis (CS) has reemerged as a global maternal and child health crisis. Kern County, California and East Baton Rouge Parish, Louisiana are among the highest CS morbidity regions in the United States. We previously reported on social-ecological and structural barriers to prenatal care and maternal syphilis testing and treatment in these two regions. The aim of this study was to examine perinatal patient’s health preferences and perceptions of patient-provider relationships in the prenatal care clinic setting.MethodsBetween May 2018 and January 2019 we conducted 20 in-depth qualitative interviews with prenatal providers and 8 focus group discussions with pregnant and postpartum individuals in Kern County and East Baton Rouge Parish. We applied an adapted health services framework to analyze participants’ understanding of health disparities and vulnerable populations; perinatal patient’s health and prenatal care preferences; and participants’ perspectives of clinical encounters in the context of prenatal care and maternal syphilis testing and treatment.ResultsSite-specific determinants of syphilis infection emerged but participants from both locations felt CS prevention efforts should be prioritized among youth, racial/ethnic minority populations, people experiencing socioeconomic limitations and people with other commonly occurring health conditions. Although perinatal patients expressed clear health preferences, they reported inconsistent receipt of respectful, patient-centered care. Inconsistencies were connected with limited ethnic and cultural competence among providers, and implicit, negative attitudes toward patients using substances, experiencing homelessness, or engaging in sex work. Providers clearly aimed to offer high quality prenatal care. However, some clinic and health systems level factors were thought to reduce positive and communicative patient-provider relationships, contributing to gaps in use of prenatal care and syphilis testing and treatment.ConclusionsOur findings suggest that interventions tailored to address setting-specific determinants (including clinic and health system factors) of disparities in CS risk could improve pregnant people’s access to prenatal care and ensure they and their sex partners receive timely syphilis screening and treatment. We recommend all prenatal care providers receive training on how to identify and mitigate implicit biases and provide competent and compassionate patient-centered care.

Characterization of Colletotrichum Isolates Causing Colletotrichum Dieback of Citrus in California.

Dieback caused by Colletotrichum spp. is an emerging disease in California citrus groves. A large-scale survey with emphasis on seasonal variations of latent infections was conducted throughout citrus orchards in Fresno, Kern, and Tulare counties in 2019 and 2020. Latent infections on citrus leaves and twigs varied markedly between years. Isolates of Colletotrichum spp. were obtained from asymptomatic tissue, and two groups were formed based on colony and spore morphology. The morphological groups were further identified based on multigene sequence analysis using the DNA regions ITS1-5.8S-ITS2, TUB2, and GAPDH. Results revealed that isolates belong to two phylogenetic species, C. gloeosporioides and C. karstii, being C. karstii more frequently isolated. Representative isolates of each species were further selected and characterized based on the response of physiological variables to temperature. Both species had similar optimum growth temperatures but differed in maximum growth rates, with C. gloeosporioides exhibiting a greater growth rate than that of C. karstii on media. Pathogenicity tests on citrus trees demonstrated the ability of C. gloeosporioides and C. karstii to cause lesions on twigs and no differences in aggressiveness. A fungicide screening performed in this study determined that the DMI fungicides were the most effective in reducing the mycelial growth of C. gloeosporioides and C. karstii. The QoI fungicides showed a remarkably inhibitory impact on spore germination of both species. On average, C. karstii was more sensitive to the DMI fungicides than C. gloeosporioides. The findings of this study provide new information to understand the Colletotrichum dieback of citrus.

Gaps in the congenital syphilis prevention cascade: qualitative findings from Kern County, California

BackgroundCongenital syphilis is preventable through timely access to prenatal care, syphilis screening and treatment of pregnant women diagnosed as infected. In 2018, California had the second highest number of congenital syphilis cases in the United States (U.S.), a nearly twofold increase in cases since 2014. This study assessed gaps in preventing congenital syphilis in the high morbidity region of Kern County, California.MethodsBetween May 2018 and January 2019, we conducted five focus group discussions with pregnant/postpartum women and ten semi-structured interviews with prenatal care providers in Kern County. Focus group and interview data were recorded, transcribed, and analyzed to identify emergent themes pertaining to facilitators and barriers at each step (prenatal care, syphilis screening and treatment) in the congenital syphilis prevention cascade.ResultsGaps in congenital syphilis prevention discussed in focus group discussions with pregnant/postpartum women were related to limited prenatal care access, social-, economic-, and cultural-barriers, and substance use and co-occurring intimate partner/domestic violence. The gaps identified from interviews with prenatal care providers included social economic vulnerabilities of pregnant women and stigma and shame around the vulnerabilities, distrust in medical system, prenatal substance use, limited prenatal substance use disorder treatment facilities, and inadequate provider training on context-specific congenital syphilis management strategies. Gaps in partner notification, screening and treatment for syphilis were brought up by pregnant/postpartum women and prenatal care providers.ConclusionsCongenital syphilis continues to increase in Kern County and throughout the U.S. In high syphilis morbidity areas, comprehensive and tailored public health approaches addressing setting-specific gaps in prenatal screening and treatment are needed.

BEHAVIORAL NICHE PARTITIONING IN EMBLYNA FRANCISCA AND EMBLYNA RETICULATA (ARANEAE, DICTYNIDAE)

I investigated behavioral niche partitioning in two morphologically similar and sympatric Emblyna spiders by collecting webs of Emblyna francisca and Emblyna reticulata from Sambucus and Atriplex plants at the Panorama Vista Preserve in Kern County, California. I measured web heights and identified prey found in webs to compare web placement and prey distributions in each habitat. Emblyna francisca webs contained more prey than did E. reticulata webs in both habitats. The two spiders had similar abundance in Atriplex, but in Sambucus, E. reticulata was more abundant than E. francisca. Emblyna reticulata placed its webs higher than E. francisca in Atriplex but not in Sambucus, and the distribution of prey in webs differed between the two spiders in Sambucus, but not in Atriplex.

Appraisal of groundwater contamination from surface spills of fluids associated with hydraulic fracturing operations

Contaminated groundwater is a priority issue on the environmental agendas of developed countries. Therefore, there is an obvious need to develop instruments and decision-making mechanisms that allow the estimation of the risk to human health due to the presence of contaminants in soils and groundwater, in a fast and reliable manner. Thus, this study aims to assess whether the spilling of hydraulic fracturing fluids prior to injection has a potential risk to groundwater quality in the Kern County Sub-basin, California, by identifying the hydrological factors and solute transport characteristics that control these risks while taking into consideration the temperature rises due to climate change. The approach uses the concept of the groundwater pollution risk based on comparing the concentration of pollutants within the water table by using a predetermined permissible level. The current average annual temperature and that by the end of the 21st century was used to estimate the diffusion of benzene through three types of soil by using HYDRUS-1D software. The software was used to predict the contaminant concentration profile of benzene in the water table with special reference to the impact of surface temperatures. The results showed that an expected rise of the surface temperature by 4.3 °C led to an increase in the concentration of benzene by 2.3 μg/l in sandy loam soil, 6.8 μg/l in silt loam soil, and finally, 2.6 μg/l in loam soil. The results show that climate change can substantially affect soil properties and their chemical constituents, which then play a major role in absorbing pollutants.

Respect, Resourcefulness, and Empathy

Using picture books to prompt philosophical conversations with children is an effective means to raise awareness of environmental issues and invite children to think creatively about their responsibility for their community and environment. In our Philosophy for Children (P4C) program at Kern County Public libraries in Bakersfield, we address environmental ethics issues as part of our regular curriculum as well as for Earth Day conversations. Children discuss how they may reuse and recycle objects that they ordinarily discard, how small acts of care may have big consequences for their community, and how they share reciprocal relationships to other living creatures, even insects. Most importantly, during such conversations children reflect and deliberate on how they can act on their insights to expand their moral imagination and empower them as citizens of their community and the world.

Identifying drivers of change and predicting future land-use impacts in established farmlands

ABSTRACT There is growing consensus that global food systems will need to undergo substantial transformations to ensure continued food security and to halt environmental degradation. Such efforts will have to include more sustainable management of existing farmscapes. Here, we examine drivers of cropland transitions between 13 crop commodities cultivated in Kern County, California. We parameterized multinomial logistic regression models of crop choices, using observed data from 2002 to 2018. We then simulated future crop choices under three scenarios exploring the consequences of climate change, water shortages and policy response, and projected impacts on three agroecosystem pressures (water-use, soil erosion, pesticide-use), and three agroecosystem services (profits, nutrition, and carbon sequestration). Agricultural land-use transitions were especially sensitive to biophysical factors, profits and neighborhood effects. Our results illustrate how climate change may lead to landscape-level crop replacement by 2050, with likely significant socio-ecological consequences.

No Consistent Link Between Dust Storms and Valley Fever (Coccidioidomycosis).

Dust storms, such as those associated with haboobs and strong regional winds, are frequently assumed to cause increases in cases of Valley fever (coccidioidomycosis). The disease is caused by inhaling arthroconidia of Coccidioides fungi that, after being disturbed from semi‐desert subsoil, have become airborne. Fungal arthroconidia can be transported in low‐wind conditions as well as in individual dust events, but there is no reliable evidence that all or most dust storms consistently lead to subsequent increases in coccidioidomycosis cases. Following a review of the relevant literature, this study examines the relationship between dust storms and coccidioidomycosis cases to determine if there is a consistent and general association between them. All recorded dust storms from 2006 to 2020 in and near the Phoenix area of Maricopa County, Arizona and the Bakersfield area of Kern County, California were used in a compositing analysis (superposed epoch analysis) of subsequent coccidioidomycosis cases in each area. Analyses of monthly and weekly disease case data showed no statistical differences in the patterns of coccidioidomycosis cases following dust storms versus non‐dust storm conditions, for the entire data set as well as for seasonal subsets of the data. This study thoroughly analyzes post‐dust storm coccidioidomycosis cases for a large set of dust storms, and it confirms and expands upon previous literature, including a recent study that measured airborne arthroconidia and found no consistent links connecting wind and dust conditions to increases in coccidioidomycosis.

Coccidioidomycosis Knowledge and Behaviors of California Hispanic Farm Workers

ABSTRACT (1) Describe knowledge, attitudes, beliefs, and behaviors related to coccidioidomycosis (Valley fever, VF) reported by farm workers in a highly endemic area to design and evaluate prevention messages and (2) identify health information sources preferred by farm workers to disseminate VF prevention messages. There were 119 primarily Mexican-born residents of two migrant farm labor housing centers in Kern County, who completed an interviewer-administered survey on VF knowledge, attitudes, beliefs, and behaviors in 2017. The 73% of participants aware of VF demonstrated a knowledge score of 53%. Over 90% erroneously believed VF was associated with pesticide exposure; approximately two-thirds believed that wearing a bandana mask was protective. Over half of respondents believed that VF was contagious, could be contracted from contaminated food or water, and caused gastrointestinal symptoms. Of those aware of VF, 75% expressed concern about becoming infected because of where they lived and working outdoors. Working outdoors in dusty conditions was the most commonly reported risk-associated work practice. Among 67 participants reporting use of respiratory protection, 94% indicated they wear a bandana; most male participants did not wear face coverings in dusty conditions. The most frequent protective work practice was wetting soil. Preferred sources of health information included television; family, friend, or co-worker; healthcare provider; and radio. Farm workers reported multiple risk factors for VF. Results identified several areas of poor knowledge, risk behavior, and preferred channels of prevention messages. Important protective behaviors are not under the control of farm workers; engagement with employers is essential.

Thematic and hotspot analysis of human-elk conflicts statewide in California

Human-wildlife conflicts are an important factor for consideration in wildlife management at urban-wildland interfaces. Effective and adaptive management of human-wildlife conflicts is needed to promote tolerance and coexistence of humans and wildlife. Anecdotal reports suggest a recent spike in human-elk conflicts in California, yet there has not been a systematic analysis of human-elk conflicts in the state. To better understand human-elk conflicts in California, we conducted thematic analysis of human-elk conflicts reported in the California Department of Fish and Wildlife’s Wildlife Incident Reporting (WIR) system. We also conducted a hotspot analysis using locations of human-elk conflicts reported in the WIR system and evaluated reports for principles of adaptive management. The WIR system contained n = 89 reports for elk and n = 78 of these described conflicts with elk. Overall, property damage (including crop damage) was the most common type of human-elk conflict reported, occurring in 69% of reports (n = 54/78), followed by non-competitive conflict with domestic animals (13%), competition with domestic livestock (12%), and habituation to humans (24%). We identified three hotspots of human-elk conflict in California in Del Norte, Kern, and San Luis Obispo counties. All incidents of human-elk conflict reported in the WIR system included at least one principle of adaptive management. We recommend modifications to the WIR system and interactions with property owners and stakeholders to enhance and facilitate adaptive management of human-elk conflicts in California.

Stratigraphic and structural controls on groundwater salinity variations in the Poso Creek Oil Field, Kern County, California, USA

Groundwater total dissolved solids (TDS) distribution was mapped with a three-dimensional (3D) model, and it was found that TDS variability is largely controlled by stratigraphy and geologic structure. General TDS patterns in the San Joaquin Valley of California (USA) are attributed to predominantly connate water composition and large-scale recharge from the adjacent Sierra Nevada. However, in smaller areas, stratigraphy and faulting play an important role in controlling TDS. Here, the relationship of stratigraphy and structure to TDS concentration was examined at Poso Creek Oil Field, Kern County, California. The TDS model was constructed using produced water TDS samples and borehole geophysics. The model was used to predict TDS concentration at discrete locations in 3D space and used a Gaussian process to interpolate TDS over a volume. In the overlying aquifer, TDS is typically <1,000 mg/L and increases with depth to ~1,200–3,500 mg/L in the hydrocarbon zone below the Macoma claystone—a regionally extensive, fine-grained unit—and reaches ~7,000 mg/L in isolated places. The Macoma claystone creates a vertical TDS gradient in the west where it is thickest, but control decreases to the east where it pinches out and allows freshwater recharge. Previously mapped normal faults were found to exhibit inconsistent control on TDS. In one case, high-density faulting appears to prevent recharge from flushing higher-TDS connate water. Elsewhere, the high-throw segments of a normal fault exhibit variable behavior, in places blocking lower-TDS recharge and in other cases allowing flushing. Importantly, faults apparently have differential control on oil and groundwater.

Perennial Crop Dynamics May Affect Long-Run Groundwater Levels

During California’s severe drought from 2011 to 2017, a significant shift in irrigated area from annual to perennial crops occurred. Due to the time requirements associated with bringing perennial crops to maturity, more perennial acreage likely increases the opportunity costs of fallowing, a common drought mitigation strategy. Increases in the costs of fallowing may put additional pressure on another common “go-to” drought mitigation strategy—groundwater pumping. Yet, overdrafted groundwater systems worldwide are increasingly becoming the norm. In response to depleting aquifers, as evidenced in California, sustainable groundwater management policies are being implemented. There has been little modeling of the potential effect of increased perennial crop production on groundwater use and the implications for public policy. A dynamic, integrated deterministic model of agricultural production in Kern County, CA, is developed here with both groundwater and perennial area by vintage treated as stock variables. Model scenarios investigate the impacts of surface water reductions and perennial prices on land and groundwater use. The results generally indicate that perennial production may lead to slower aquifer draw-down compared with deterministic models lacking perennial crop dynamics, highlighting the importance of accounting for the dynamic nature of perennial crops in understanding the co-evolution of agricultural and groundwater systems under climate change.

Identifying and characterizing pesticide use on 9,000 fields of organic agriculture

Notwithstanding popular perception, the environmental impacts of organic agriculture, particularly with respect to pesticide use, are not well established. Fueling the impasse is the general lack of data on comparable organic and conventional agricultural fields. We identify the location of ~9,000 organic fields from 2013 to 2019 using field-level crop and pesticide use data, along with state certification data, for Kern County, CA, one of the US’ most valuable crop producing counties. We parse apart how being organic relative to conventional affects decisions to spray pesticides and, if spraying, how much to spray using both raw and yield gap-adjusted pesticide application rates, based on a global meta-analysis. We show the expected probability of spraying any pesticides is reduced by about 30 percentage points for organic relative to conventional fields, across different metrics of pesticide use including overall weight applied and coarse ecotoxicity metrics. We report little difference, on average, in pesticide use for organic and conventional fields that do spray, though observe substantial crop-specific heterogeneity.