Central Valley Research Articles

Water Balance and Nitrate and Salt Exports from a Saline–Sodic Irrigation District in Castelflorite (Huesca, NE Spain)

In the current context of climate change, there is growing interest in the optimization of water management in irrigated areas, in semi-arid environments. The design of adequate adaptation and mitigation measures requires specific data at different scales of the water management hierarchy, up to basin level. In this work, the irrigation and drainage system of San Pedro de Castelflorite Irrigation Community (Huesca province, NE Spain), first set up as a flood irrigation system around 1970 and then modernized to sprinkler irrigation around 2008, was studied over two irrigation seasons. The land in this basin, with a surface of 11,450 ha, is affected by severe sodicity problems, which impedes cultivation in large areas. Most of the drainage water discharges into Clamor Vieja ravine, in which the quantity and quality of drainage, using water, salt, and nitrogen balances, were monitored. The water regime was found to be essentially regulated by irrigation. From the water balance, the consumed and the recoverable fractions were estimated at 76% and 23%, respectively, and the depleted beneficial fraction for the irrigated area at 73%. A predominance of salt dissolution processes over precipitation processes was found, with salt exports of approximately 2000 kg ha−1·year−1. The nitrogen exported by the drainage water was 7 kg N·ha−1·year−1. This value, remarkably lower than those reported for nearby basins in the central Ebro valley, can be attributed to the flooding of rice fields and to the low permeability of the soils present in this basin, which would hamper nitrate washing through the soil profile.

Non-invasive genetic monitoring for the threatened valley elderberry longhorn beetle.

The valley elderberry longhorn beetle (VELB), Desmocerus californicus dimorphus (Coleoptera: Cerambycidae), is a federally threatened subspecies endemic to the Central Valley of California. The VELB range partially overlaps with that of its morphologically similar sister taxon, the California elderberry longhorn beetle (CELB), Desmocerus californicus californicus (Coleoptera: Cerambycidae). Current surveying methods are limited to visual identification of larval exit holes in the VELB/CELB host plant, elderberry (Sambucus spp.), into which larvae bore and excavate feeding galleries. Unbiased genetic approaches could provide a much-needed complementary approach that has more precision than relying on visual inspection of exit holes. In this study we developed a DNA sequencing-based method for indirect detection of VELB/CELB from frass (insect fecal matter), which can be easily and non-invasively collected from exit holes. Frass samples were collected from 37 locations and the 12S and 16S mitochondrial genes were partially sequenced using nested PCR amplification. Three frass-derived sequences showed 100% sequence identity to VELB/CELB barcode references from museum specimens sequenced for this study. Database queries of frass-derived sequences also revealed high similarity to common occupants of old VELB feeding galleries, including earwigs, flies, and other beetles. Overall, this non-invasive approach is a first step towards a genetic assay that could augment existing VELB monitoring and accurately discriminate between VELB, CELB, and other insects. Furthermore, a phylogenetic analysis of 12S and 16S data from museum specimens revealed evidence for the existence of a previously unrecognized, genetically distinct CELB subpopulation in southern California.

Inter-population differences in salinity tolerance of adult wild Sacramento splittail: osmoregulatory and metabolic responses to salinity.

The Sacramento splittail (Pogonichthys macrolepidotus) is composed of two genetically distinct populations endemic to the San Francisco Estuary (SFE). The allopatric upstream spawning habitat of the Central Valley (CV) population connects with the sympatric rearing grounds via relatively low salinity waters, whereas the San Pablo (SP) population must pass through the relatively high-salinity Upper SFE to reach its allopatric downstream spawning habitat. We hypothesize that if migration through SFE salinities to SP spawning grounds is more challenging for adult CV than SP splittail, then salinity tolerance, osmoregulatory capacity, and metabolic responses to salinity will differ between populations. Osmoregulatory disturbances, assessed by measuring plasma osmolality and ions, muscle moisture and Na+-K+-ATPase activity after 168 to 336h at 11‰ salinity, showed evidence for a more robust osmoregulatory capacity in adult SP relative to CV splittail. While both resting and maximum metabolic rates were elevated in SP splittail in response to increased salinity, CV splittail metabolic rates were unaffected by salinity. Further, the calculated difference between resting and maximum metabolic values, aerobic scope, did not differ significantly between populations. Therefore, improved osmoregulation came at a metabolic cost for SP splittail but was not associated with negative impacts on scope for aerobic metabolism. These results suggest that SP splittail may be physiologically adjusted to allow for migration through higher-salinity waters. The trends in interpopulation variation in osmoregulatory and metabolic responses to salinity exposures support our hypothesis of greater salinity-related challenges to adult CV than SP splittail migration and are consistent with our previous findings for juvenile splittail populations, further supporting our recommendation of population-specific management.

Probabilistic seismic liquefaction hazard assessment of Kathmandu valley, Nepal

Earthquakes are frequent in the Himalayas and almost all moderate to strong earthquakes have caused enormous losses of lives and property in Kathmandu Valley, Nepal. Several historical earthquakes depicted that considerable loss was attributed to liquefaction induced failure in structures and infrastructures. Existing liquefaction studies have mostly used deterministic approach to obtain the factor of safety against liquefaction. Thus, to update the conventional deterministic liquefaction analysis results, this study performs probabilistic seismic liquefaction hazard assessment of Kathmandu valley considering wide range of earthquake magnitudes and four return periods: 73, 475, 2475, and 5000 years. Liquefaction probabilities for 88 locations across Kathmandu Valley are estimated and compared with the historical occurrence to validate the results. The liquefaction hazard maps for all four return periods are prepared for all the earthquake magnitudes for 1.5 m, 3 m, 4.5 m, and 6 m depths. The sum of findings highlights that the central valley, and eastern and western fringes have higher liquefaction probabilities than the other parts.

An Anatomic and Radiographic Study of the Distal Tibial Epiphysis.

Although the undulating shape of the distal tibial epiphysis is well recognized, its anatomic features have not been well quantified in the literature. To guide the placement of surgical implants about the distal tibial physis, we investigated the topographical anatomy of the distal tibial epiphysis and explored the ability of standard radiographs to visualize the physis. We studied 30 cadaveric distal tibial epiphyses in specimens 3 to 14 years of age. Anteroposterior (AP) and lateral radiographs were obtained of each specimen and then repeated after flexible radiopaque markers were placed on the major undulations. All radiographs were analyzed to determine the height or depth of each landmark, and measurements with and without markers for each landmark were compared using intraclass correlation coefficients (ICC). In 9 specimens, similar measurements were obtained on high-resolution 3-dimensional (3D) surface scans. There were 4 distinct physeal undulations usually present: an anteromedial peak (Kump's bump), a posterolateral peak, an anterior central valley, and a posterior central valley. On the 3D scans, Kump's bump averaged 5.0 mm (range, 3.0 to 6.4 mm), the posterolateral peak 2.4 mm (range, 1.2 to 5.0 mm), the anterior valley 1.3 mm (range, 0 to 3.6 mm), and the posterior valley 0.77 mm (range, 0 to 2.7 mm). Lateral radiographs with markers correlated with measurements from 3D scans better than those without markers (ICC=0.61 vs. 0.24). For AP radiographs, correlation was good to excellent regardless of marker use (ICC=0.76 vs. 0.66). There are 4 major undulations of the distal tibial physis. Kump's bump is the largest. A centrally placed epiphyseal screw in the medial/lateral direction or screws from anterolateral to posteromedial and anteromedial to posterolateral would tend to avoid both valleys. Particular caution should be taken when placing metaphyseal screws in the anteromedial or posterolateral distal tibia. Physeal undulations were more difficult to visualize on the lateral view. This study provides quantitative data on the topography of the distal tibial physis to aid hardware placement. Lateral views should be interpreted with caution, as the physeal undulations are not as visible, whereas AP views can be interpreted with more confidence.

New data on the ecological distribution ofEuphorbia resiniferaO.Berg in the Beni Mellal-Khenifra region

Euphorbia resiniferaO. Berg, also called Euphorbusresin, is a species belonging to the Euphorbiaceae family. It is endemic to the Beni Mellal Khenifra region and extends discontinuously between El Ksiba and Demnate. Currently, this plant is known as a meliferous species and its product is considered as a terroir product with a Protected Geographical Indication (PGI). However, few studies have conducted on its ecology and particularly its mapping in relation to the environmental conditionswhere it thrives. That’s why in this study, we tried to establish, for the first time in the region of Beni Mellal, a distribution mapping of E.resiniferaaccording to the ecological needs of the plant, the exploration of high-resolution satellite imagery and on the field by observing a representative sample of the study area. Results showed that it spread from Demnate to Elksiba in the Atlas piedmont area but appears as scattered individuals from Demnate to AitOurir due to a complexity of factors mainly related to the soil characteristics, paleogeography and the climate exacerbated by the negative results of anthropogenic impacts. It extends also into the central high Atlas valley as small isolated units which reach 1900 m of altitude. This could explain why other ecological requirements should be considered in terms of the distribution of this endemic species in the context of climate change.

Advances in phenology and harvest characterization of the Chilean Vitis sp. germplasm collection and its use in table grape breeding

Germplasm collection and characterization is essential for plant breeding. Chile holds a collection of 347 Vitis accessions at Instituto de Investigaciones Agropecuarias, La Platina, that have been successfully used to develop new table grape cultivars such as Maylen®. Located in the central valley of Chile, a section of the Vitis collection was characterized for two consecutive seasons for phenology as well as fruit quality parameters at harvest. In terms of phenology, the collections can be grouped in four main clusters, with a higher representation of individuals at the middle and late timing. Fruit phenotyping showed significant differences among wine and table grapes for cluster and berry weight, seed number and fresh seed weight, polar and equatorial diameters, as well as the ratio among these parameters. Interestingly, rachis weight, a novel parameter associated with fruit storage capacity, did not show differences among groups. Other novel traits, such as the combination of commercial seedleesness and berry equatorial diameters above 2cm were less represented, suggesting the need to create and introduce genetic variability for table grape breeding purposes.

Measurement of terrestrial gamma radiation dose rate and radioactivity levels in the southern hilly regions of Manipur, India

The terrestrial gamma radiation levels and associated dose rates were estimated at 120 different sites with 12 soil samples in the southern hilly regions of Manipur, India, consisting of Churachandpur and Chandel district, by using NaI (Tl) scintillator-based Micro-R survey meter and high-purity germanium detector. The observed annual effective dose in this study area ranges from 0.37 to 1.51 mSv/y, with a mean value of 0.85 ± 0.16 mSv/y. Whereas Churachandpur and Chandel districts showed a mean value of 0.88 ± 0.18 (ranges: 0.67 to 1.51) mSv/y and 0.83 ± 0.14 (ranges: 0.37–1.24) mSv/y, respectively. This southern region of Manipur shows slightly higher values of annual effective dose as compared with the earlier reported value of about 0.7 mSv/y for the central valley region of Manipur, and world average value of about 0.4 mSv/y, reported by United Nations Scientific Committee on the Effects of Atomic Radiation (2000). The soil analysis for226Ra,232Th, and40K of this area gives an average activity concentration of 44.3 (ranges: 23.8–78.6) Bq/kg, 169.1 (ranges: 83.6–305.1) Bq/kg, and 1489.1 (ranges: 752.5–2426.8) Bq/kg, respectively.

A Network Analysis of PM <sub>2.5</sub> Pollution in Santiago: Which Locations Have the Biggest Impact on Pollution Levels?

Air pollution and, in particular, PM 2.5 particulate matter is a significant issue in Santiago, the capital of Chile. Santiago's pollution problem is exacerbated by its unique geographic location nestled against the Andes mountain range in the central valley of Chile. This paper uses network models, first developed to analyse linkages and systemic risk in the financial system, to identify those locations in the city that are most systemically important for explaining PM 2.5 level across the city. High average concentrations are associated with both systemically important locations and those that are most sensitive to pollution arriving from other locations. A detailed picture of the links across the city can help direct official efforts to combat pollution.

Cercetări efectuate la Băile Figa în anii 2016–2019 și considerații privind deslușirea valențelor unui peisaj salin hibrid / Research carried out at Băile Figa during 2016–2019 Revealing the potential of a hybrid saltscape

Cercetări efectuate la Băile Figa în anii 2016–2019 și considerații privind deslușirea valențelor unui peisaj salin hibrid / Research carried out at Băile Figa during 2016–2019 Revealing the potential of a hybrid saltscape

First Documented Report for Lythrum salicaria (Lythraceae) in Louisiana

Purple loosestrife (Lythrum salicaria) is documented for the first time for Louisiana in Plaquemines Parish, extending its range southward about 310 km. Three species of Lythrum are now known for Louisiana, and four species have been recorded for the central Gulf and lower Mississippi valley regions. A key to species and regional distributional data are provided for L. salicaria.

Vegetation history after the late period of the Last Glacial Age based on phytolith records in Nangodani Valley basin, southern part of the Aso caldera, Japan

ABSTRACTVegetation history after the late period of the Last Glacial Age has been reconstructed using phytolith records obtained from three tephra sections in the Nangodani Valley basin, southern part of the Aso caldera, south‐west Japan. The topography of the Nangodani Valley basin is divided into three types: somma (caldera rim and wall), caldera floor (central valley) and post‐caldera central cone slope. The vegetation transitions after the late period of the Last Glacial Age in the basin vary between these topographic types. The differences can be explained based on human activities in the valley basin. Grassland dominated by Sasa and Pleioblastus dwarf bamboos (before 8 ka) and Miscanthus and other Andropogoneae pampas grasses (after 8 ka) occurred in the central valley and on the post‐caldera central cone slope, which were strongly affected by human activities including a long period of burning. In contrast, forest with an understory of Bambusoideae plants was preserved on the caldera rim and wall, which was inaccessible because of its steep topography, during the Holocene.

Nurse Practitioner Student Clinical Placements: A Rural Community Immersion

This article describes a collaboration between a university and a medically underserved area in California’s central valley. Students participate in a community-based clinical immersion to provide care to a medically underserved population. Faculty collaborate with community-based partners to develop and implement clinical experiences. Students are provided opportunities to meet clinical course objectives while developing skills necessary to care for a medically underserved population as part of an interdisciplinary team.

Path Coefficient Analysis of Some Prominent Agronomic Traits in Castor (Ricinus communis L.) Germplasm

Background and Objective: Castor (Ricinus communis L.) is a diploid plant with chromosome number of 2n=20 which belongs to family of Euphorbiaceous and genus Ricinus. Correlation alone is not efficient for variability studies. So, it should be in conjugation with Path co- efficient analysis to know the direct and indirect effects. This study was conducted to assess the role of evaluating path coefficient analysis in castor.
 Materials and Methods: A Field experiment was carried out to determine direct and indirect effects of yield and its components in castor accessions at Melkassa, central rift valley of Ethiopia under irrigation in 2014. The experiment was conducted using a randomized complete block design with 3 replications and a total of 48 castor accessions were evaluated.
 Results: Number of capsules per plant, number of primary branches per plant, length of inter node and hundred seed weight had exerted positive direct effect for both at phenotypic and genotypic path analysis.Phenotypic and genotypic path analysis showed that the number of capsules per plant, number of secondary branches per plant, length of inter node, days to 50% second flowering and seed yield exhibited positive direct effect on oil content. 
 Conclusion: Thus, traits like number of capsules per plant, number of secondary branches per plant, length of inter nod and days to 50% second flowering should be given emphasis in improving seed yield.

Modeling managed aquifer recharge processes in a highly heterogeneous, semi-confined aquifer system

Widespread groundwater overdraft in alluvial aquifer systems like the Central Valley (CV) in California, USA, has increased interest in managed aquifer recharge (MAR). Like most clastic sedimentary basins, recharge to the productive semi-confined CV aquifer system remains a challenge due to the presence of nearly ubiquitous, multiple confining units (silt and clay) that limit recharge pathways. Previous studies suggest the presence of interconnected networks of coarse-texture sand and gravel deposits that bypass regional confining units over a small fraction of the CV near the American and Cosumnes rivers. Here, variably saturated infiltration and recharge processes were simulated across a domain that includes high-resolution representation of the heterogeneous alluvial geologic architecture in this area. Results show that recharge potential is highly dependent on subsurface geologic architecture, with a nearly 2 order-of-magnitude range of recharge across the domain. Where interconnected coarse-texture recharge pathways occur, results show that these features can (1) accommodate rapid, high-volume MAR and (2) propagate widespread and rapid pressure responses over multi-kilometer distances in the semi-confined aquifer system. For all MAR simulations, results show that the majority of MAR is accommodated by filling unsaturated-zone (UZ) pore volume. Results also show that coarse-texture UZ facies (where present) accommodate the majority of MAR volume during early time, but fine-texture facies ultimately accommodate the majority of the total MAR volume, even for coarse-dominated sites. These findings highlight the large variability of MAR potential across the landscape and demonstrate the importance of fine-texture facies for accommodating MAR in alluvial aquifer systems.

Ceramic exchange and the shifting political landscape in the Valley of Oaxaca, Mexico, 700 BCE-200 CE

In this paper we utilize archaeometric analyses to reexamine the organization and spatial scale of ceramic exchange in the central Valley of Oaxaca, Mexico, with the goal of elucidating how those interactions were related to political centralization, interpolity conflict, and social negotiation during the period when the Monte Albán (Zapotec) state formed. Building on extensive geochemical analyses of the valley’s clays and Formative ceramics, we employ relatively fine-grained provenance data to trace the movement of vessels from producers to consumers, and model the different forms of exchange through which pottery was distributed. The results of these analyses accord with earlier models positing the development of market exchange, at least of utilitarian vessels. However, the number and scale of market networks fluctuated through time due to political fragmentation and conflict prior to the subjugation of the entire valley by Monte Albán. At the same time, some elaborate pottery likely was distributed via non-market forms of exchange, such as gift-giving and direct acquisition from sponsored potters. The circulation of such pottery helped to build and maintain intra- and interpolity alliances, as well as to reinforce—and in some cases resist—increasing social differentiation within the early Zapotec state.

Smallholder farmers’ awareness and perceptions of climate change in Adama district, central rift valley of Ethiopia

Rural smallholder farmers, who exercise rain fed agriculture for their livelihoods, make up the largest proportion in Ethiopia. This article examined the awareness and perception of rural smallholder farmers about climate change in Adama district, central rift valley region of Ethiopia. Primary data were collected from 351 sample smallholder farmers through questionnaires. Focus group discussions and key informant interviews were also employed. The result revealed that though the majority of smallholder farmers reported that they were aware of climate change, it has been found out that they have limited knowledge about climate change impacts and threats posed to various climate sensitive sectors, for example, agriculture, water, energy etc. The result also indicated that majorities of the respondents perceived that climate is changing. Smallholder farmers of rural areas should get relevant and up-to-date climate change information services. It has also been recommended that national meteorological agency and agricultural office of the district should reach the mass and provide training for the rural farming communities.

Zinc status of riverside populations of the rivers Solimoes and Negro in the state of Amazonas, Brazil

Zinc nutrition has been shown to be critically limiting among urban populations of the central Amazon valley, but no information on the zinc status of rural populations has been published. Nutrition surveys were carried out on the river Solimoes and the river Negro in years 1976/7. Hair samples collected at that time were analysed for their zinc content, by Atomic Absorption Spectrophotometry. The mean hair zinc value of children aged under seven years from the river Negro (140 µg/g) was about one third lower than hair values from the river Solimoes (204 µg/g) with high statistical significance (p< 0.001). Hair zinc levels were influenced by a variety of non-dietary conditions in these riverine children populations, including anthropometric classifications and gastrointestinal parasites, and these are discussed. The significantly lower hair zinc levels in children on the river Negro than in children on the river Solimoes may be part of the reason why young child stunting rates are higher on the river Negro. The importance of zinc status for reproduction is also discussed, especially the evidence for relationships to still teratogenesis and still births, the latter being six times more common among mothers on the river Negro than among those on the Solimoes at that time. Although no indicators of maternal zinc status were measured, the findings of zinc deficiency in their young children support the hypothesis that these mothers were also suffering from zinc deficiency. It also suggests poor zinc status may be associated with the lower population densities found along the banks of the river Negro as compared to that of the river Solimoes. The situation seems unlikely to have improved in the forty years since these observations were made and may even be getting worse. Interventions are suggested that would allow this type of situation to be remedied.

A Comparison Between Ray-Traced GFS/WRF/ERA and GNSS Slant Path Delays in Tropical Cyclone Meranti

Tropical cyclone (TCs) prediction has improved in the last decade, but studying their structure and dynamics remains a challenging task due to limited in situ observations. The global navigation satellite system (GNSS) technique enables retrieving the state of the troposphere with high accuracy in all weather conditions. In this article, we use GNSS slant total delays (STDs) to verify the quality of the weather models during the passage of the TC Meranti, which was the strongest TC in 2016. STDs observed from 28 GNSS stations in Taiwan are compared with the STDs reconstructed from three meteorological data sets: the weather research and forecasting (WRF) model, the global forecast system (GFS), and the ERA-Interim (ERA) using a 2-D ray-tracing technique. Furthermore, two strategies were tested—including and excluding the delays due to liquid and ice water content. The results reveal a good consistency between the GNSS and the ray-traced STDs. The best agreement was found for the WRF, with a mean difference of −0.5 mm and a standard deviation of 29.4 mm when the hydrometeor delay was included. The mean hydrometeor contribution reached up to 2.8 mm for the WRF, while for the ERA and GFS, the contribution to the total delay was negligible. The recorded absolute percent differences were greater for the northern HENC station (mostly within 0.8%) than for the southern GOLI station (on average below 0.5%) due to a closer location to the passing Meranti. The most significant biases were seen in the ERA (around 7%) and the GFS (exceeding −3%) for the PLIM station, located in the central mountain range valley.

Identifying hidden biocomplexity and genomic diversity in Chinook salmon, an imperiled species with a history of anthropogenic influence

Biocomplexity is an important mechanism for population resilience in changing environments. However, we are just beginning to understand how to identify biocomplexity so that species management efforts promote resilience and stability. Genomic techniques are emerging as an important method for identifying biocomplexity. Central Valley (CV) Chinook salmon are an example of a species at risk of extinction if better methods for identifying and protecting biocomplexity are not employed. To address this knowledge gap, we employed restriction site associated DNA sequencing to conduct the first genomic study of all major populations of CV Chinook salmon. We found greater population structure across the Central Valley than previously documented. Additionally, we show evidence for differentiation and adaptation within migratory phenotypes despite high levels of gene flow. We also determined that genomic data can vastly improve our ability to assign individuals to their natal populations, even as they mix during migration, a finding that will assist management practices. These results demonstrate how genomic study can greatly improve our ability to identify and conserve biocomplexity.