Central California Research Articles

Managing invasive hybrids with pond hydroperiod manipulation in an endangered salamander system.

When invasive and endangered native taxa hybridize, the resulting admixture introduces novel conservation challenges. Across a large region of central California, a hybrid swarm consisting of admixed endangered California tiger salamanders (CTS) (Ambystoma californiense) and introduced barred tiger salamanders (BTS) (Ambystoma mavortium) has replaced native populations, threatening the genetic integrity of CTS and the vernal pool systems they inhabit. We employed a large-scale, genomically informed field experiment to test whether shortening breeding pond hydroperiod would favor native CTS genotypes. We constructed 14 large, seminatural ponds to evaluate the effect of hydroperiod duration on larval survival and mass at metamorphosis. We tracked changes in non-native allele frequencies with a 5237-gene exon capture array and employed a combination of custom Bayesian and generalized linear models to quantify the effect of pond duration on salamander fitness. Earlier work on this system showed hybrid superiority under many conditions and suggested that hybrids are favored in human-modified ponds with artificially long hydroperiods. Consistent with these earlier studies, we found overwhelming evidence for hybrid superiority. Very short hydroperiods substantially reduced the mass (1.1-1.5 fold) and survival probability (10-13 fold) of both native and hybrid larvae, confirming that hydroperiod likely exerts a strong selective pressure in the wild. We identified 86 genes, representing 1.8% of 4723 screened loci, that significantly responded to this hydroperiod-driven selection. In contrast to earlier work, under our more natural experimental conditions, native CTS survival and size at metamorphosis were always less than hybrids, suggesting that hydroperiod management alone will not shift selection to favor native larval genotypes. However, shortening pond hydroperiod may limit productivity of hybrid ponds, complementing other strategies to remove hybrids while maintaining vernal pool ecosystems. This study confirms and expands on previous work that highlights the importance of hydroperiod management to control invasive aquatic species.

Prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and feline enteric coronavirus (FECV) in shelter-housed cats in the Central Valley of California, USA.

Non-human animals are natural hosts for the virus causing COVID-19 (severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]) and a diversity of species appear susceptible to infection. Cats are of particular concern because of their close affiliation with humans and susceptibility to infection. Cats also harbour feline enteric coronavirus (FECV). Our objectives were to document the prevalence of SARS-CoV-2 and FECV in feline populations with high turnover and movement among households in the Central Valley of California, USA. A cross-sectional study of 128 shelter and foster cats and kittens in the Central Valley of California was performed from July to December 2020. PCR was performed on rectal and oropharyngeal samples to detect SARS-CoV-2 RNA and on rectal samples to detect FECV RNA. Among 163 rectal and oropharyngeal fluid samples gathered from sheltered and fostered cats and kittens in central California, SARS-CoV-2 nucleic acids were not detected from any cat or kitten. In contrast, FECV nucleic acids were detected in 18% of shelter-housed cats; 83% of these positive samples were collected from cats housed in adjacent cages. These data may be helpful when considering the allocation of resources to minimise the harm of FECV and SARS-CoV-2 in household pets and shelter environments.

Diagnostic Delays in Cutaneous Coccidioidomycosis: a Report from Central California.

Cutaneous Coccidioidomycosis (CC) infection can present with a wide variety of clinical presentations and is well known as a 'great imitator'. We performed a retrospective analysis of patients with CC in a large referral center in Central Valley, California, from 2010 to 2022 using the ICD9 and ICD10 codes for coccidioidomycosis and CC. We identified forty patients with CC during the study period. The mean age of the study population was 43 years (with standard deviation of 14.08). Among these, 60% were men and 40% women. The appearance of the lesions varied from ulcers, plaques, nodules, blisters, cellulitis, and abscesses. The most common site of CC lesions was in the lower extremities (42.5%), followed by upper extremities (30%), chest and abdomen, head and neck (25% each). Only 22.5% of the 40 cases were diagnosed as CC and 15% were diagnosed as erythema nodosum. Rest were diagnosed initially as bacterial cellulitis in 37.5%, tinea in 7.5% and others in 12.5%. There was resolution of the cutaneous lesions in all patients with antifungal treatment. The mean time of diagnosis from onset of symptoms on an average was 12 weeks (8-16weeks) in our study with 75% cases initially misdiagnosed. Comprehensive knowledge about the manifestations and evaluation of CC among primary care providers and emergency room physicians is essential to prevent delays in diagnosis and treatment.

Comparative C, N, and S cycling along a Californian grassland chronosequence

Carbon (C), nitrogen (N), and sulfur (S) are elements strongly influenced by biological cycling and redox reactions in soils, but few comparative analyses have investigated the behaviors of these elements with time. Thus, we examined changes in content and isotope composition of soil profiles along a chronosequence (58–212 kyr) of marine terraces on the central California coast, in an area with significant background geochemical research. Unlike in other chronosequences in more humid locations, the total C, N, and S in these soils did not vary strongly with age, possibly due to the retention of phosphorus (P). The total pools of soil N and S cannot be explained by wet deposition of NO3 and SO4 alone, suggesting other sources of atmospheric inputs such as NH4+ and dimethyl sulfide. Total C and N declined in a characteristic logarithmic pattern with depth, while S did not. The ratio of extractable soil nitrate (NO3) to total N declined with depth, suggesting strong biological demand via various avenues. In contrast, the ratio of extractable sulfate (SO4) to total S increased with depth, suggesting that S was in biological excess. We used a simple reactive transport model to integrate the depth profiles of total C and N and their isotope values. The depth trends of total concentrations suggested one-pool residence times of approximately 500 to 1000 y, consistent with turnover times calculated by mass balance. Depth trends of stable isotope values indicated that N is isotopically fractionated at a magnitude twice that of C, consistent with observed 15N-depleted nitrous oxide (N2O) emissions during the dry summer months. The isotope composition of S (total and SO4) suggests some isotope enrichment during biogeochemical cycling, but far less than observed for N. Thus, despite significant chemical weathering and elemental loss over time, the biogeochemical cycles of C, N, and S remain relatively unaffected by soil age in this climatic setting.

Hydrology, rather than wildfire burn extent, determines post‐fire organic and black carbon export from mountain rivers in central coastal California

AbstractCoastal mountain rivers export disproportionately high quantities of terrestrial organic carbon (OC) directly to the ocean, feeding microbial communities and altering coastal ecology. To better predict and mitigate the effects of wildfires on aquatic ecosystems and resources, we must evaluate the relationships between fire, hydrology, and carbon export, particularly in the fire‐prone western United States. This study examined the spatiotemporal export of particulate and dissolved OC (POC and DOC, respectively) and particulate and dissolved black carbon (PBC and DBC, respectively) from five coastal mountain watersheds following the 2020 CZU Lightning Complex Fires (California, USA). Despite high variability in watershed burn extent (20–98%), annual POC, DOC, PBC, and DBC concentrations remained relatively stable among the different watersheds. Instead, they correlated significantly with watershed discharge. Our findings indicate that hydrology, rather than burn extent, is a primary driver of post‐fire carbon export in coastal mountain watersheds.

Traffic-related air pollution and Parkinson's disease in central California

BackgroundPrior studies suggested that air pollution exposure may increase the risk of Parkinson's Disease (PD). We investigated the long-term impacts of traffic-related and multiple sources of particulate air pollution on PD in central California. MethodsOur case-control analysis included 761 PD patients and 910 population controls. We assessed exposure at residential and occupational locations from 1981 to 2016, estimating annual average carbon monoxide (CO) concentrations - a traffic pollution marker - based on the California Line Source Dispersion Model, version 4. Additionally, particulate matter (PM2.5) concentrations were based on a nationwide geospatial chemical transport model. Exposures were assessed as 10-year averages with a 5-year lag time prior to a PD diagnosis for cases and an interview date for controls, subsequently categorized into tertiles. Logistic regression models were used, adjusting for various factors. ResultsTraffic-related CO was associated with an increased odds ratio for PD at residences (OR for T3 vs. T1: 1.58; 95% CI: 1.20, 2.10; p-trend = 0.02) and workplaces (OR for T3 vs. T1: 1.91; 95% CI: 1.22, 3.00; p-trend <0.01). PM2.5 was also positively associated with PD at residences (OR for T3 vs. T1: 1.62; 95% CI: 1.22, 2.15; p-trend <0.01) and workplaces (OR for T3 vs. T1: 1.85; 95% CI: 1.21, 2.85; p-trend <0.01). Associations remained robust after additional adjustments for smoking status and pesticide exposure and were consistent across different exposure periods. ConclusionWe found that long-term modeled exposure to local traffic-related air pollution (CO) and fine particulates from multiple sources (PM2.5) at homes and workplaces in central California was associated with an increased risk of PD.

Indigenous Foodways as Persistence in the Alta California Mission System

AbstractThis article investigates Indigenous persistence within Mission Santa Clara de Asís in central California through the analysis of animal food remains. The Spanish colonial mission system within Alta California had a profound social and ecological impact on Indigenous peoples, altering traditional subsistence strategies and foodway patterns. Past research has highlighted the continued use of precolonial foods within the Alta California mission system alongside the daily consumption of colonial-style beef stews. This article expands on that literature to consider how Indigenous and colonial residents differentially acquired ingredients and prepared daily meals within the Alta California colonial mission system. This assessment demonstrates a sharp divergence between Indigenous and colonists’ daily diet, manifested in the continued use of wild food resources by Indigenous people as well as the maintenance of precolonial culinary practices in the preparation of cattle meat for daily stews. These findings complicate our understanding of foodways within the Spanish mission system and expand our understanding of Indigenous autonomy within conditions of colonialism.

Where are the whales? Continued acoustic monitoring efforts of California’s Central Coast

Understanding and conserving ocean ecosystems is a difficult, but important task made easier with bioacoustic technology. Although marine mammal monitoring efforts can be done with visual surveys, they often lack temporal information on a finer scale. Long-term passive acoustic monitoring efforts of critical migratory species can provide detailed information about the region’s marine soundscape that is key to conservation efforts. The aim of our project is to establish a long-term bioacoustic monitoring station off the coast of central California and help close the gap in our understanding of marine mammal presence along the Pacific coastline. The goals put forth by the bioacoustic lab for this academic year include (1) determining probable species presence, (2) ascertaining temporal (day/night) variations of vocalizations, and (3) examining key differences in species and call type between two deployments from Fall 2022 and Winter 2023. These comparisons will be crucial to help develop a baseline understanding of seasonal and temporal variations of the soundscape in our region. We aim to implement various long-term deployments in order to gather more complete and consistent bioacoustic data in our local waters. These deployments and the subsequent analysis will contribute to large scale marine mammal monitoring and conservation efforts. [This project was made possible by a grant from the Santa Rosa Creek Foundation and the COAST undergraduate research fund.]

Size‐selective predation effects on juvenile Chinook salmon cohort survival off Central California evaluated with an individual‐based model

AbstractVariation in the recruitment of salmon is often found to be correlated with marine climate indices, but mechanisms behind environment–recruitment relationships remain unclear and correlations often break down over time. We used an ecosystem modeling approach to explore bottom‐up and top‐down mechanisms linking a variable environment to salmon recruitment variations. Our ecosystem model incorporates a regional ocean circulation submodel for hydrodynamics, a nutrient‐phytoplankton‐zooplankton submodel for producing planktonic prey fields, and an individual‐based model (IBM) representing juvenile Chinook salmon (Oncorhynchus tshawytscha), combined with observations of foraging distributions and diet of a seabird predator. The salmon IBM consists of modules, including a juvenile salmon growth module based on temperature and salmon–prey availability, a behavior‐based movement module, and a juvenile salmon predation mortality module based on juvenile salmon size distribution and predator–prey interaction probability. Seabird–salmon interactions depend on spatial overlap and juvenile salmon size, whereby salmon that grow past the size range of the prey distribution of the predator will escape predation. We used a 21‐year historical simulation to explore interannual variability in juvenile Chinook salmon growth and predation‐mediated survival under a range of ocean conditions for sized‐based mortality scenarios. We based a series of increasingly complex predation scenarios on seabird observational data to explore variability in predation mortality on juvenile Chinook salmon. We initially included information about the predator spatial distribution, then added population size, and finally the predator's diet percentage made up of juvenile salmon. Model agreement improves with added predator complexity, especially during periods when predator abundance is high. Overall, our model found that when the fraction of juvenile salmon in seabird diet increased relative to alternate prey (e.g., Northern anchovy Engraulis mordax, and juvenile rockfish Sebastes spp.), there was a concomitant decrease in salmon cohort survival during their first year at sea.

Traffic-related air pollution and Parkinson’s disease in central California

Traffic-related air pollution and Parkinson’s disease in central California

Testing the reliability and validity of the modified Amsterdam Inventory for Auditory Disability and Handicap in career firefighters in the United States.

Firefighters are routinely exposed to loud noise that put them at risk for hearing loss. A reliable and valid measure to assess firefighters' hearing function is important. This study aims to test the reliability and validity of the modified Amsterdam Inventory for Auditory Disability and Handicap ((m)AIADH) in firefighters. A cross-sectional study was conducted using a convenience sample of 239 career firefighters from six partnered fire departments in Central Texas and Northern California. The internal consistency, convergent and criterion validity, and the ability to discriminate groups by measured hearing, perceived hearing, and a combination of measured and perceived hearing, were examined using the total score and score for each of the five subscales of the (m)AIADH. The study participants were primarily men (93%). Satisfactory internal consistency was revealed for the (m)AIADH with Cronbach's alpha above 0.80 for all five subscales. Criterion analysis presented a moderate correlation between the (m)AIADH and the average of hearing threshold at high frequencies (4, 6, and 8 kHz). For convergent validity, the (m)AIADH was moderately to highly related with perceived hearing. There were statistically significant differences in the total (m)AIADH score and the five subscales for measured hearing thresholds except for "intelligibility in quiet." The (m)AIADH also showed a discriminative ability to distinguish between the group with good perceived hearing and the group with bad perceived hearing. The (m)AIADH is a reliable and valid measure to assess various dimensions of hearing function among firefighters.

Young, Black/African American, and Latino communities are left behind despite legislative efforts in California to reduce HIV/STI disparities.

Sexually transmitted infections (STI) have been on the rise in the United States with racial/ethnic minority groups, gay and bisexual men, and youth experiencing the highest STI and HIV infection rates. In 2022, California became the first state in the nation to pass legislation, Senate Bill 306 (SB 306), requiring health care plans to cover the costs of home test kits for STIs, including HIV. This study examines provisions within SB 306 and its potential to reduce STI and HIV disparities among key demographic groups and geographic regions within California. Ecological cross-sectional study involving 58 California counties. Descriptive statistics and choropleth maps compared HIV/STI prevalence rates, uninsured rates, demographic composition, and healthcare provider coverage across California counties. Three geographically weighted Poisson regression analyses were conducted to separately examine the association between proportion of uninsured and HIV, gonorrhea, and chlamydia prevalence rates. HIV/STI rates were significantly and positively associated with the proportion of uninsured residents in Central and Southern California counties. These counties had a higher proportion of demographic groups vulnerable to HIV/STI including a large Latino, Black/African American, and younger (age 15-24) population but had a lower rate of healthcare providers with prescription authority for home testing kits, which is a requirement under SB 306. Cutting-edge solutions are needed to stem the rising tide of new STI and HIV infections. While SB 306 is novel and innovative in intent, its coverage gaps will increase disparities and inequities among historically underserved populations.

An agent-based model to quantify energetics, movement and habitat selection of mid-continent mallards in the Mississippi Alluvial Valley

The dynamics of wintering waterfowl populations at the landscape scale are the result of complex interactions of environmental, behavioral and energetic drivers. Agent-based models provide a method to directly link these factors in a spatially explicit framework and allow the emergence of patterns from the aggregation of individual agent actions. We adapted the Spatially-explicit Waterbird Agent-based Model Program (SWAMP), originally developed for waterfowl in central California, to simulate a basin-scale population of mallards (A. platyrhynchos) wintering in the Mississippi Alluvial Valley over a four-month period (November–February). Simulated agents move within the landscape, foraging on areas made available based on a probabilistic inundation status, and converting food resources to endogenous energy. The model uses a high-resolution map of eastern Arkansas waterfowl habitats and incorporates a hierarchical habitat selection system that enables mallards to relocate at increasing scales in response to changing food availability. We validated the performance of modeled mallard body condition and behavioral metrics under a range of environmental conditions against expected outcomes derived from empirical data and found that the simulation produced realistic representations of changes in flight distances, energy expenditure, lipid storage, and foraging habitat use in response to depleting food resources over time. We discuss the model's applicability as a tool to quantify waterfowl response to a range of environmental conditions and to evaluate scenarios of landscape composition and configuration in the context of waterfowl population management.

Use of historical isoscapes to develop an estuarine nutrient baseline.

Coastal eutrophication is a prevalent threat to the healthy functioning of ecosystems globally. While degraded water quality can be detected by monitoring oxygen, nutrient concentrations, and algal abundance, establishing regulatory guidelines is complicated by a lack of baseline data (e.g., pre-Anthropocene). We use historical carbon and nitrogen isoscapes over ~300 years from sediment cores to reconstruct spatial and temporal changes in nutrient dynamics for a central California estuary, Elkhorn Slough, where development and agriculture dramatically enhanced nutrient inputs over the past century. We found strong contrasts between current sediment stable isotopes and those from the recent past, demonstrating shifts exceeding those in previously studied eutrophic estuaries and substantial increases in nutrient inputs. Comparisons of contemporary with historical isoscapes also revealed that nitrogen sources shifted from a historical marine-terrestrial gradient with higher δ15N near the inlet to amplified denitrification at the head and mouth of the modern estuary driven by increased N inputs. Geospatial analysis of historical data suggests that an increase in fertilizer application - rather than population growth or increases in the extent of cultivated land - is chiefly responsible for increasing nutrient loads during the 20th century. This study demonstrates the ability of isotopic and stoichiometric maps to provide important perspectives on long-term shifts and spatial patterns of nutrients that can be used to improve management of nutrient pollution.

Internal waves

Internal waves are ubiquitous oceanographic features that occur in various forms across the world’s oceans. They manifest themselves as interface waves across ocean density layers that represent the interplay between buoyancy and gravitational forces, and are typically classified as linear and nonlinear internal waves. Nonlinear internal waves are characterized by isopycnal displacements that can exceed 30 m, and current velocities that approach 1 m/s. Internal wave energy converters, if developed, could have the advantage of no surface expression and provide for the availability of renewable ocean energy in regions of scant surface wave energy resources.&#x0D; Here, internal wave energies were computed at two locations: the New Jersey continental shelf and the coast of Central California. The available energy resource calculated for internal waves was then compared against surface gravity wave resources at each of these locations. Results suggest that the internal wave energy flux is comparable to that of surface waves on the New Jersey continental shelf during the summer of 2006 but is two orders of magnitude lower than that of surface waves in Central California during the summer of 2017. When expressed in terms of forces on a cylindrical structure, internal wave forces are an order of magnitude lower than that of surface waves on identically sized cylinders. However, the forces of the two resources are comparable when the diameter of the cylinder is doubled for the internal wave calculations. This suggests that while a larger energy converter would be required to harness internal wave energy, the larger size could be a reasonable tradeoff for advantages such as the lack of surface expression and the availability of energy in regions of limited surface wave energy resources.&#x0D; These results could potentially pave the way for longer-time scale characterization of internal waves and the development of devices to harness this energy resource (thereby powering the Blue Economy), while augmenting the portfolio of marine renewable energy resources. Further, the dominance of internal wave energy resources during summer seasons when the water column is stratified can augment the surface wave energy resource that can be diminished during the summer season.

Thermal characteristics of early life stages of Laminaria farlowii, a deep-water kelp from Southern and Central California

Thermal characteristics of early life stages of Laminaria farlowii, a deep-water kelp from Southern and Central California

Toward Improved Regional Hydrological Model Performance Using State‐Of‐The‐Science Data‐Informed Soil Parameters

AbstractAccurate soil moisture and streamflow data are an aspirational need of many hydrologically relevant fields. Model simulated soil moisture and streamflow hold promise but models require validation prior to application. Calibration methods are commonly used to improve model fidelity but misrepresentation of the true dynamics remains a challenge. In this study, we leverage soil parameter estimates from the Soil Survey Geographic (SSURGO) database and the probability mapping of SSURGO (POLARIS) to improve the representation of hydrologic processes in the Weather Research and Forecasting Hydrological modeling system (WRF‐Hydro) over a central California domain. Our results show WRF‐Hydro soil moisture exhibits increased correlation coefficients (r), reduced biases, and increased Kling‐Gupta Efficiencies (KGEs) across seven in situ soil moisture observing stations after updating the model's soil parameters according to POLARIS. Compared to four well‐established soil moisture data sets including Soil Moisture Active Passive data and three Phase 2 North American Land Data Assimilation System land surface models, our POLARIS‐adjusted WRF‐Hydro simulations produce the highest mean KGE (0.69) across the seven stations. More importantly, WRF‐Hydro streamflow fidelity also increases, especially in the case where the model domain is set up with SSURGO‐informed total soil thickness. The magnitude and timing of peak flow events are better captured, r increases across nine United States Geological Survey stream gages, and the mean KGE across seven of the nine gages increases from 0.12 to 0.66. Our pre‐calibration parameter estimate approach, which is transferable to other spatially distributed hydrological models, can substantially improve a model's performance, helping reduce calibration efforts and computational costs.

Abyssal hydrothermal springs-Cryptic incubators for brooding octopus.

Does warmth from hydrothermal springs play a vital role in the biology and ecology of abyssal animals? Deep off central California, thousands of octopus (Muusoctopus robustus) migrate through cold dark waters to hydrothermal springs near an extinct volcano to mate, nest, and die, forming the largest known aggregation of octopus on Earth. Warmth from the springs plays a key role by raising metabolic rates, speeding embryonic development, and presumably increasing reproductive success; we show that brood times for females are ~1.8 years, far faster than expected for abyssal octopods. Using a high-resolution subsea mapping system, we created landscape-scale maps and image mosaics that reveal 6000 octopus in a 2.5-ha area. Because octopuses die after reproducing, hydrothermal springs indirectly provide a food supplement to the local energy budget. Although localized deep-sea heat sources may be essential to octopuses and other warm-tolerant species, most of these unique and often cryptic habitats remain undiscovered and unexplored.

Diet quality and Parkinson’s disease: Potential strategies for non-motor symptom management

IntroductionParkinson’s disease (PD) is now considered a systemic disease, and some phenotypes may be modifiable by diet. We will compare the diet quality and intake of specific nutrients and food groups of PD patients with household and community controls to examine how diet may influence PD clinical features. MethodsWe conducted a case-control study of 98 PD patients and 83 controls (household = 53; community = 30) in central California, assessing dietary habits over the past month and calculating the Healthy Eating Index (HEI)-2015. We employed multivariate logistic and linear regression analyses to assess associations between diet and PD status, PD symptom profiles, and medication, adjusting for relevant confounders. ResultsPD patients had a lower HEI score than controls, with an OR of 0.65 (95% CI: 0.45, 0.94) per 10-points increase in HEI. Lower-quality diet was characterized by higher intakes of carbohydrates, total and added sugars, and trans fats and lower intakes of fiber, folate, unsaturated fatty acids, protein, and fat. PD patients with chronic constipation had a 4.84 point lower HEI score than those without (β per 10-point in HEI: −0.48; 95% CI: −0.97, −0.00). Furthermore, patients on high dopamine agonist doses consumed more sugar than those on lower doses. ConclusionPD patients consume a lower-quality diet compared to household and community controls. Dietary modifications may alleviate non-motor symptoms like constipation, and promoting a healthy diet should become a part of routine care and disease management for PD patients, with special attention on agonist-treated and hyposmic patients.

Alterations in Ferrisia gilli (Hemiptera: Pseudococcidae) phenology in California pistachios and potential impacts on controls.

The mealybug, Ferrisia gilli Gullan, attacks important crops such as almonds, grapes, and pistachios in California. In pistachios, F. gilli has 3 generations per year, and a single insecticide application timed to the presence of first instars of the first or second generation provided sufficient control. This strategy has, recently, become less effective, and here we tested the possible explanation that F. gilli life stages are smeared, with different life stages present concurrently, reducing the efficacy of a single pesticide application. We monitored F. gilli populations and their natural enemies in central California pistachio orchards from 2021 through 2022. We found the first generation of F. gilli was synchronous, but occurred 3 wk earlier than previously reported. Subsequent generations were smeared. Increased yearly temperatures are a likely explanation for the changes observed in phenology. Almost all natural enemies found were lacewings (n > 10,000). Parasitoids were recovered from pistachios in 2021 (n = 4) and 2022 (n = 164), most were hyperparasitoids. Based on these studies, recommendations are made to monitor F. gilli in early May rather than late May to better target insecticide applications for the first instars.