Central Valley Research Articles

Assessing space and time changes in daily maximum temperature in the Ebro basin (Spain) using model‐based statistical tools

AbstractThere is continuing interest in the investigation of change in temperature over space and time. For this analysis, we offer statistical tools to illuminate changes temporally, at desired temporal resolution, and spatially, using data generated from suitable space–time models. The proposed tools can be used with the output from any suitable model fitted to any set of spatially referenced time series data. The tools to assess space and time changes include spatial surfaces of probabilities and spatial extents for events defined by exceeding a threshold. The spatial surfaces capture the spatial variation in the probability or risk of an exceedance event, while the spatial extents capture the expected proportion of incidence of an event for a region of interest. This approach is used analyse the changes in daily maximum temperature in an inland Mediterranean region (NE of Spain) in the period 1956–2015. The area is very heterogeneous in orography and climate, including the central Ebro valley and part of the Pyrenees. We use a collection of daily temperature series obtained from simulation under a Bayesian daily temperature model fitted to 18 stations in that area. The results for the summer period show that, although there is an increasing risk in all the events used to quantify the effects of climate change, it is not spatially homogeneous, with the largest increase arising in the centre of the Ebro valley and the Eastern Pyrenees area. The risk of an increase in the average daily maximum temperature from 1966–1975 to 2006–2015 higher than 1°C is higher than 0.5 over all of the region, and close to 1 in the previous areas. The extent of daily maximum temperature higher than the reference mean has increased 3.5% per decade. The mean of the extent indicates that 95% of the area under study has suffered a positive increment of the average temperature, and almost 70% an increment higher than 1°C.

Drought trends and farmers' perceptions in Siraro district, the central valley of Ethiopia

Drought trends and farmers' perceptions in Siraro district, the central valley of Ethiopia

Knowledge, attitude and participation intention to use and management of wetlands: evidence from the central rift valley of Ethiopia

Knowledge, attitude and participation intention to use and management of wetlands: evidence from the central rift valley of Ethiopia

Environmental influences on common waterhemp germination and tolerance to salinity and herbicides

AbstractThis study investigated the potential of common waterhemp [Amaranthus tuberculatus (Moq.) Sauer] invading the semiarid, salinity‐prone areas of the Central Valley (CV) of California, and its response to commonly used herbicides. Despite its status as one of the worst weeds in the US agriculture, common waterhemp is not very prevalent in California. Limited information exists on its germination ecology and potential to invade the CV, or its response to herbicides. Seeds were collected from a local common waterhemp population, and germination was tested under a range of water potential (0 to −4.17 MPa), salinity (0–25 dS m−1), and pH (5–9) levels. Plant tolerance to salinity at different electrical conductivity (EC) levels (0–20 EC) and mortality under applications of label rates of postemergence herbicides (glyphosate, glufosinate, rimsulfuron, or caprylic + capric acid) at the 4‐ to 6‐leaf or 8‐ to 10‐leaf stage were evaluated. Results showed that the seeds were moderately tolerant to drought and salinity as 50% and 55% of them germinated at −0.5 MPa and 10 EC, respectively. Germination was greater in neutral to alkaline than in acidic conditions. Plants were not very tolerant to salinity as 96% of them died at 10 EC. Most of the plants were controlled by herbicide applications at the 4‐ to 6‐leaf stage, but escapes occurred at the later stage. Therefore, the local population has the potential to germinate and establish in the CV but can be controlled by tested herbicides when applied at early stages.

Conceptual model of groundwater flow in a volcanic-sedimentary aquifer system of the Andean region of Chimborazo, Ecuador

The Chimborazo volcano is located in Ecuador's northern Andes and is one of the world's tallest mountains. The central valley of Riobamba's morphology, structure, and groundwater flow networks are all influenced by the evolution of this stratovolcano. Both the urban and rural populations in this area rely on groundwater extracted from volcano-sedimentary aquifers. This study presents a conceptual model of the groundwater flow system in the lower Chambo River basin (LCRB) based on the interpretation of geological, hydrogeological, hydrochemical, and stable isotope (δ18O and δ2H) data from 23 wells, 10 springs, two sources of surface water, and rainwater. The Tertiary-Quaternary volcanic-sedimentary infill of the Inter-Andean Valley, that overlies the Jurassic-Cretaceous metamorphic bedrock of the Eastern and Western cordilleras, gave rise to three multilayer aquifers (Llo-Guano, Riobamba, and Yaruques). In these aquifers, groundwater flows from the recharge of Chimborazo glaciers to deep circulation zones of low-elevation lands in Riobamba. In this pathway, groundwater evolves from acidic - low temperature - low electric conductivity bicarbonate waters to alkaline - high temperature - high electric conductivity sulfate waters discharged in the Chambo River. The stable isotope data confirmed the hypothesis of different types of water changing and interacting in the flow direction, demonstrating a dynamic hydrogeological system that evolves from the recharge area in Chimborazo, Igualata, and Altar volcanoes to the discharge area in the Chambo River.

Scoring, ranking, and technoeconomics of carbon capture and storage opportunities in the central valley of California

Previous studies of geological carbon storage are reviewed, redefined, and evaluated to provide proper capturable emission amounts and candidate storage sites in the Southern San Joaquin Basin (California). The LCFS eligible capturable GHG emissions from thermal EOR facilities were 11.4 MtCO2/y. Also, the capturable emission amounts and location of other large emitters in both Kern County and southern California were identified. The estimated CO2 storage resource in the 7 qualified saline formations ranged from 16.6 to 52 GtCO2 whereas that in 35 qualified hydrocarbon fields ranged from 0.45 to 1.15 GtCO2. Among the 35 hydrocarbon fields, 15 CO2-EOR candidate fields with storage resources of 0.36 to 0.88 GtCO2 are located in Kern County. Altogether, 41 storage sites including 7 hydrocarbon fields, 32 saline storage sites, and 2 stacked storage sites were defined as CO2 storage locations. The 41 CO2 storage sites in and around Kern County were linked to selected large CO2 emitters in Imperial, Kern, Los Angeles, Orange, San Bernardino, Santa Barbara, San Luis Obispo, and Ventura Counties. Importantly, the technoeconomics of prospective storage sites and emitters were analyzed using SimCCS (Scalable infrastructure model for Carbon Capture and Storage). Regional GHG emissions from oil and gas facilities such as EOR steam generators and CHPs can be captured and stored economically as a result of LCFS and 45Q credits. The 45Q credit value and duration are critical factors to incentivize CCS deployment. The deployment scenarios evaluated teach that the Southern San Joaquin basin is an excellent potential regional carbon storage hub.

Deer, drought, and warfare: Managing risk in the central Illinois river valley (CIRV) from the eleventh through fourteenth centuries

We investigated how Mississippian residents of the Central Illinois River Valley (CIRV) altered their hunting strategies in response to climate change and warfare in the 13th and 14th centuries. The CIRV, located in west-central Illinois just north of Greater Cahokia, was characterized by optimal climatic conditions in the 11th and 12th centuries, followed by centuries of drought and warfare. We integrated paleoclimatic reconstructions and evidence of violence with bone collagen and apatite isotopic analyses on white-tailed deer remains to investigate how CIRV residents minimized risks associated with white-tailed deer hunting. This is the first study in this region to effectively use δ13Capatite measurements to show the selective consumption of maize by white-tailed deer. Our results indicate that there were varied responses to climate change and conflict that were socially contingent upon community size. Notably, deer hunted by residents of Roskamp, occupied in the 13th century during the period of warfare, had highly elevated δ13Capatite values, demonstrating residents partook in garden hunting.

Dynamic Risk Assessment of Landslide Hazard for Large-Scale Photovoltaic Power Plants under Extreme Rainfall Conditions

Large-scale photovoltaic power plants located in highland mountainous areas are vulnerable to landslides due to extreme rainfall, posing a significant threat to the normal operation of photovoltaic power plants. However, limited research has been conducted on landslide risk assessment specifically tailored to large photovoltaic power plants, with most studies focusing on static assessments that lack long-term sustainability in risk assessment and prediction. In this paper, a dynamic study on landslide risk at a large photovoltaic power plant project under extreme rainfall conditions is conducted. Firstly, the factors in landslide susceptibility assessment based on typical landslide characteristics in the study area are selected and an assessment index database using mapping units to extract the relevant factors is established. Subsequently, the ANP-FBN model is employed to evaluate the landslide susceptibility of large photovoltaic power plant sites. Furthermore, an assessment index system for landslide hazard vulnerability is developed by considering population, economic, and material vulnerabilities, and the AHP method is adapted to assess landslides vulnerability in the study area. Finally, the landslide rainfall threshold with the susceptibility and vulnerability assessment results are coupled to achieve a dynamic assessment of landslide hazard risk at large photovoltaic power plant sites under extreme rainfall conditions. The findings highlight that the central valley and the eastern steep slope of the study area are the primary “high” and “very high” risk areas. Moreover, with the increase in rainfall duration, the risk level of landslide hazards in the study area also rises.

Acoustic Forceps Based on Focused Acoustic Vortices with Different Topological Charges.

For enhanced energy concentration with improved flexibility for object manipulation, a focused acoustic vortex (FAV) is designed using a sector planar piston transducer array and acoustic lens that can produce the effective concentration of the acoustic field to perform the focusing function. Compared to the Gaussian beam, which tends to cause the object to deviate from the axis of acoustic propagation, FAVs can form a central valley region to firmly bind the objects, thus preventing off-target effects. The heat energy in the paraxial region is transferred to the vortex center in the form of heat transfer so that the temperature-sensitive liposomes captured can quickly release drugs, which has a good effect on targeted drug administration. The focused acoustic wave stopped acting on the tissue (gel) for 2 s, the temperature of the vortex center continued to rise, reaching 41.5 °C at the moment of 3.7 s, at which point the liposomes began to release the drug. The FAVs capture the drug and use its thermal effect to achieve accurate and rapid treatment. The simulation results show that the drug release temperature of temperature-sensitive liposomes can be achieved by controlling the action time of the vortices. This study provides a reliable theoretical basis for the clinical application of targeted drugs.

Multi-proxy evidence of unprecedented hydroclimatic change in a high Arctic proglacial lake: Linnévatnet, Svalbard

ABSTRACT Svalbard is at the forefront of sea ice, marine, and terrestrial environmental change in the Arctic and so can be viewed as an example of what may be expected in other high latitude regions influenced by the North Atlantic Current. However, there are few highly resolved (subdecadal) paleoclimate records from this area that provide a long-term perspective on recent climatic changes. Here, we investigate a new composite sedimentary sequence from Linnévatnet, western Spitsbergen, spanning the last ~2,000 years. The chronology of this new composite laminated sequence is supported by four radiometric dates. Prior to conducting paleoclimate investigations on these lake sediments, we investigated the sediment sources entering Linnévatnet. Sediment samples collected around the lake’s watershed indicate that the main sediment sources come from the eastern carbonate valley wall as well as Linnéelva, the main river system. Micro-X-ray fluorescence (µ-XRF) results indicate that calcium is the largest component of sediment delivered to the delta-proximal basin, where the sedimentary record was collected. Percentage organics deduced from loss-on-ignition measurements reveal an antiphased relationship with calcium and magnetic susceptibility, implying that the sediment loading at the core site is largely modulated by the alternation of calcium derived from carbonates of the eastern flanks of the valley and by coal-bearing sandstone from Linnéelva, derived from the main river inflow that drains the central valley. Linnéelva is mainly fed by snow and glacier meltwaters from Linnébreen, the small valley glacier now located 7 km south of Linnévatnet. Because Linnébreen is underlain by coal-bearing sandstone, organic content in Linnévatnet lake sediments can be used as an indicator of glacier activity. Annually resolved parameters—that is, calcium and grain size—were found to be strongly correlated to temperature inferred from nearby Lomonosovfonna δ18O ice record as well as the wider reconstructed Northern Hemisphere winter temperature. The coarsest grain size, highest calcium values, and lowest concentration of organics occurred just in recent years, suggesting that glacier influence on the sedimentary input to Linnévatnet is now at an all-time low in the context of the past millennia.

Spatio-temporal variability and rainfall trend affects seasonal calendar of maize production in southern central Rift Valley of Ethiopia

Understanding rainfall variability is important to establish crop calendar related agronomic decisions. To this end, we defined start and end of seasons, analyzed dry spell and evaluated conditional risks of alternative planting dates using a thirty years daily rainfall data across southern central rift valley of Ethiopia. Results showed that the probability of annual rainfall being greater than 1000 mm was 97, 24, 94, and 61%, in Dilla, Bilate, Shamana, and Hawassa clusters, respectively. The variability of annual total rainfall in the lowland areas of Dilla and Bilate was above 25%, whereas for Shamana and Hawassa was below 20%. Variability of seasonal rainfall during FMAM was 33.7%, which is higher than ONDJ (27.1%) and JJAS (27.9%), which could lead to maize plants suffering moisture stress during FMAM season. The onset of rains had variability of 29.2, 19.5, 17.5 and 26.5%, and also LGP showed variability of 22.8, 22.1, 21.2 and 20.3% in Shamana, Bilate, Hawassa, and Dilla clusters, respectively. Moreover Shamana, Bilate, Hawassa and Dilla clusters are hit by agricultural drought in one out of 2.61, 2.3, 2.5 and 2.5 years, respectively. Model based analysis of conditional risk of farmers planting dates also showed a success rate of less than 10, 7, 40 and 63% for maize variety in Shamana, Bilate, Hawassa and Dilla clusters, respectively. However, the success rate of risk taker farmers’ is higher than anticipated by the model. The farmers who take risk were encouraged in Shamana cluster by local edaphic, physiographic, socioeconomic and climatic differences. Hence, there is a need to seek real time local agro-metrological advisory and follow the necessary tactical and strategic farming decisions. Moreover, there is also a need to incorporate local factors with modern climate models to obtain synchronized calendar estimates.

Impact of COVID-19 pandemic on alcohol-related hepatitis admissions: Analysis of nationwide data 2016-2020

BackgroundThe coronavirus disease 2019 (COVID-19) pandemic was a public health crisis affecting medical, social, and psychological wellness. In a previous study, we reported a rise in alcohol-related hepatitis (ARH) cases between 2019 and 2020 in the central valley of California. Our goal in the current study was to assess the impact of COVID-19 on ARH at a national level. Materials and methodsWe used data from the 2016 to 2020 National Inpatient Sample. All adult patients diagnosed with ARH (ICD10 K70.1 and K70.4) were included. Information was collected regarding patient demographics, hospital characteristics, and severity of hospitalization. We analyzed the annual percentage changes (PC) between 2016-2019 and 2019-2020 to assess the impact of COVID-19 on hospitalizations. Multivariate logistic regression analysis was performed to identify factors associated with increased ARH admissions between 2016 and 2020. ResultsA total of 823,145 patients were admitted with ARH. The total number of cases increased from 146,370 in 2016 to 168,970 in 2019 (annual percentage change (PC) 5.1%), while the cases increased to 190,770 in 2020 (PC 12.4%). The PC in women was 6.6% between 2016 and 2019, which increased to 14.2% between 2019 and 2020. In men, PC increased by 4.4% between 2016 and 2019 to 12.2% between 2019 and 2020. On multivariate analysis, after adjusting for patient demographics and hospital characteristics, there was 46% increased odds of admission with ARH in 2020, compared to 2016. The total number of deaths increased from 8725 in 2016 to 9190 in 2019 (PC 1.7%), while the total number of deaths increased to 11,455 in 2020 (PC 24.6%). ConclusionsA sharp rise in the cases of ARH between 2019 and 2020 was noted, which aligned with the COVID-19 pandemic. Not only did total hospitalization increase, but an increase in mortality was also noted, reflecting higher severity in the patients admitted during the COVID-19 pandemic.

Presence of the toxigenic fungi Aspergillus spp. and Fusarium spp. in Musca domestica L. (Diptera: Muscidae) collected from dairy farms

The objective of the study was to identify the presence of toxigenic fungi Aspergillus spp. and Fusarium spp. in domestic flies collected from dairy farms. We selected 10 dairy farms distributed in the central valley of the state of Aguascalientes, México. The flies were trapped using entomological traps with an olfactory attractant in 7 sites of the farm (silo-cutting surface, feed store, milking parlor, 3 feeders, and the rearing room). The fungi were cultivated in Sabouraud agar through direct sowing by serial dilutions to obtain the isolates, and a taxonomical identification was carried out under the microscope. The aflatoxins and zearalenone production capacity of the pure isolates were quantified using the ELISA test. The flies were present in all of the capture sites (45.3 flies, 567 mg, trap per day). We obtained 50 isolates of Aspergillus spp. genus, 12 of which produced aflatoxins (327 ± 143 µg/kg), whereas from 56 of the Fusarium spp. isolates, 10 produced large quantities of zearalenone (3,132 ± 665 µg/kg). These results suggest that the presence of domestic flies on dairy farms can constitute a source of dissemination for toxigenic fungi that can eventually contaminate grains and forage that are part of the daily cattle diet.

Performance and Cost Comparison of Photovoltaic and Diesel Pumping Systems: In Central Rift Valley of Ethiopia

Diesel pumps have extensively used for irrigation water pumping. However, this causes challenges both in terms of economic factors (fuel costs) and environmental impacts (emits air pollution). An alternative solution is using renewable energy sources. In this regard, a battery less solar PV energy system was designed and evaluated was designed and evaluated for the geographic location and metrological data of Dugda woreda, representing the central rift valley of Ethiopia. Performance testing were conducted on sunny days of April month and with time intervals of from 9:00 am to 5:00 pm, again the respective solar radiation ranges between 385.8 to 862.2 W m^(-2) h^(-1). The solar photovoltaic pumping has been evaluated with the head levels of 10, 12, 15, and 18 m. Accordingly the result showed that, PV system size can irrigate a tomato field of 0.33-0.75 ha with a mean daily water use of 8.7 and 17.4 m^3 〖day〗^(-1) at head levels of 10 and 18 meters, respectively. After evaluation, the maximum water flow rate has been at the midday day from 12:00 am to 1:00 pm. Comparative economic evaluation of the solar-powered water pump system and diesel pump devices were done using cycle cost breakdown and the cost of water per unit volume. Thus the long term economics of water pumping using solar photovoltaic and diesel pumping systems showed a cost of 1.33 〖ETB m〗^(-3) and 3 ETB m^(-3), respectively. The result demonstrated that photovoltaic water pump systems are more affordable for the long-term services of small to medium-scale farms than gasoline water pumps.

Disentangling the spread dynamics of insect invasions using spatial networks

IntroductionDescribing and understanding spatiotemporal spread patterns in invasive species remains a long-standing interdisciplinary research goal. Here we show how a network-based top-down approach allows the efficient description of the ongoing invasion byDrosophila suzukiiin Chile.MethodsTo do so, we apply theoretical graph methods to calculate the minimum cost arborescence graph (MCA) to reconstruct and understand the invasion dynamics ofD. suzukiisince the first detection in 2017. This method estimates a directed rooted weighted graph by minimizing the total length of the resulting graph. To describe the temporal pattern of spread, we estimate three metrics of spread: the median dispersal rate, the median coefficient of diffusion, and the median dispersal acceleration.ResultsThe estimated MCA shows that over four years,D. suzukiicolonized a ~1,000km long strip in the central valley of Chile, with an initial phase with long paths and connections and no clear direction pattern, followed by a clearer north–east propagation pattern. The median dispersal rate for the entire period was 8.8 (7.4–10.6, 95% CI), while the median diffusion coefficient was 19.6 meters2/day (13.6–27.9, 95% CI). The observed spread dynamics and the log-normal distribution of accelerations are consistent with long-distance dispersal events.DiscussionThe complexities of real landscapes cannot be summarized in any model, but this study shows how an alternative top-down approach based on graph theory can facilitate the ecological analysis of the spread of an invasive species in a new territory.

California's future economic collapse due to A decrease of quality of life in the hispanic/latinx Fieldworker population of the central valley

California's future economic collapse due to A decrease of quality of life in the hispanic/latinx Fieldworker population of the central valley

Valorization of Wheat Crop Waste in Araucanía, Chile: Development of Prototype of Thermal Insulation Material for Blowing Technique and Geographical Analysis

Houses in the operational stage consume around 40% of the world’s energy, and most of it is consumed by air conditioning. This generates several problems, especially in cities, where biomass combustion is the most widely used form of heating. For this reason, environmental regulation works in parallel with energy efficiency, where efficient and low-impact thermal insulating materials are key to reduce the energy demand and fuel consumption to generate comfort in dwellings. This work considers the valorization of wheat straw from the Araucanía region of Chile, to develop a prototype for a thermal insulating material applied through the blowing technique. The results show the insulation potential of the fiber, which, in post-chopping conditions and at an average density of 80 [kg/m3], has thermal conductivity of 0.034 [W/mK]. This value is much better than that of glass wool and other inorganic materials sold in the Chilean market. In addition, the developed material can be incorporated into partitions using the blowing technique, improving the execution time for the thermal insulation section. Finally, it is indicated that a good option to install a processing plant is in the central valley of the region, specifically in the communes of Victoria and Perquenco.

Application of Spectrometry for Determining the Solar Radiation of Deciduous Trees’ Shade: A Passive Energy Conservation Approach for Mediterranean Climates

Deciduous trees are well known for controlling solar gains in buildings, contributing to energy savings in a sector that consumes 35% of global energy. However, there is still a lack of information about the real thermal impact that deciduous trees have. This work proposes a new method that is cheap and easy to implement to quantify the shading efficiency of different types of deciduous trees in hot seasons. The results can be applied in energy evaluations of buildings. The trees selected belong to the central valley of Chile, which is characterized by hot summers and cold winters. The trees selected can also be found in other parts of the world. A spectrometer is used for measuring the amount of solar radiation (irradiance) that is present in the shadow of trees, measuring wavelengths between 339 nm and 750 nm (mostly within the visible light range). The full referential irradiance spectrum of the site is obtained by calibrating the standard ASTM G-173-03. At the site, the spectrometer is used to obtain the visible light range, while the infrared radiation (IR) and ultraviolet (UV) radiation ranges are obtained from the literature. Our results indicate that the analyzed deciduous trees reduce an average of 82% of the solar radiation. This information will help project designers during the building energy efficiency design phase by representative modeling of the solar radiation gains allowed by deciduous trees.

The role of nonequilibrium LO phonons, Pauli exclusion, and intervalley pathways on the relaxation of hot carriers in InGaAs/InGaAsP multi-quantum-wells

Under continuous-wave laser excitation in a lattice-matched In0.53Ga0.47As/In0.8Ga0.2As0.44P0.56 multi-quantum-well (MQW) structure, the carrier temperature extracted from photoluminescence rises faster for 405 nm compared with 980 nm excitation, as the injected carrier density increases. Ensemble Monte Carlo simulation of the carrier dynamics in the MQW system shows that this carrier temperature rise is dominated by nonequilibrium LO phonon effects, with the Pauli exclusion having a significant effect at high carrier densities. Further, we find a significant fraction of carriers reside in the satellite L-valleys for 405 nm excitation due to strong intervalley transfer, leading to a cooler steady-state electron temperature in the central valley compared with the case when intervalley transfer is excluded from the model. Good agreement between experiment and simulation has been shown, and detailed analysis has been presented. This study expands our knowledge of the dynamics of the hot carrier population in semiconductors, which can be applied to further limit energy loss in solar cells.

Population size and diurnal activity patterns of Bohor reedbuck (Redunca redunca Pallas, 1767) in the compound of Alage Agricultural College, Central Rift Valley of Ethiopia

Abstract Bohor reedbuck is a medium-sized, even-toed ungulate species endemic to Africa. Its population is gradually declining, and an estimation of Meta populations is required to determine its current population status and as an input for conservation action. To this end, this study aimed to investigate this species’ population size and diurnal activity patterns in the compound of Alage Agricultural College, Central rift valley of Ethiopia. A total count was conducted to determine the population size of Bohor reedbuck by dividing the study area into different blocks. Continuous focal animal observations were used to collect data on activity patterns by recording group activities with five minutes intervals. The results revealed that the mean population size of Bohor reedbuck counted during the study period was (SE) with a density of 1.74 per km2. Females formed the dominant group in the population. From the mean total population size of Bohor reedbucks, 47.42% were adults. The mean group size of Bohor reedbuck was (SE). Feeding (, 45.81%) was the dominant mean diurnal activity pattern of Bohor reedbuck, followed by Resting (, 31.91%), whereas grooming (, 3.51%) was the least performed activity. There was a significant difference between the diurnal activities performed by Bohor reedbuck (). The studied compound is an important refuge for this species, and minimum management interference can increase the population size of Bohor reedbuck in the area.