Year In Southern California Research Articles

Depression and Anxiety Among US Children and Young Adults

Data from surveys show increased mental health disorders in youths. However, little is known about clinical diagnosis over time. To assess the incidence, prevalence, and changes from 2017 to 2021 for depression and anxiety diagnosed clinically among children, adolescents, and young adults and to identify potential disparities. This cohort study included approximately 1.7 million individuals aged 5 to 22 years in Southern California. Data were extracted from electronic medical records; International Statistical Classification of Diseases, Tenth Revision (ICD-10), codes were used to identify depression and/or anxiety diagnosis for each study year from January 1, 2017, to December 31, 2021. Rates were stratified by age, gender, race and ethnicity, estimated household income, weight status, and comorbidity history. Changes over time and association with these variables were assessed using Poisson regression. Data were analyzed between June 1, 2022, and November 29, 2023. Clinical diagnosis of (1) depression and (2) anxiety without a depression diagnosis using ICD-10 codes. Among the 1.7 million participants, mean (SD) age was approximately 14 (5) years, and 51% were male. In terms of race and ethnicity for each study year, approximately 50% of participants were Hispanic; 8%, non-Hispanic Asian; 8%, non-Hispanic Black; and 23%, non-Hispanic White. From 2017 to 2021, depression diagnosis increased by 55.6% (from 1.35% to 2.10%) for incidence and 60.0% (from 2.55% to 4.08%) for prevalence; anxiety without depression diagnosis increased by 31.1% (from 1.77% to 2.32%) for incidence and 35.2% (from 3.13% to 4.22%) for prevalence (P < .001 for trend). The increases in rates were higher during the COVID-19 pandemic (2020-2021) than before the pandemic (2017-2019), except for depression incidence. Rates increased across all subgroups. Rates were highest for subgroups aged 14 to 17 and 18 to 22 years; female participants; those of non-Hispanic American Indian or Alaska Native, non-Hispanic White, or multiple races or ethnicities; and subgroups with higher household income, obesity (and underweight for anxiety without depression), or comorbidities. Among these factors, age was the most important factor for depression diagnosis, whereas weight status was the most important factor for anxiety without depression diagnosis. This cohort study, using electronic medical record data from a large integrated health care system, found an increase in clinically diagnosed depression from 2017 to 2021, with a higher increase during the COVID-19 pandemic and higher rates in some subgroups. Equally important, this study identified high rates and an increase in clinical diagnosis of anxiety without a depression diagnosis. These results support the increased need in public health and health care effort to combat the mental health crisis in youths.

Outdoor Ultrafine Particulate Matter and Risk of Lung Cancer in Southern California.

Rationale: Particulate matter ⩽2.5 μm in aerodynamic diameter (PM2.5) is an established cause of lung cancer, but the association with ultrafine particulate matter (UFP; aerodynamic diameter < 0.1 μm) is unclear. Objectives: To investigate the association between UFP and lung cancer overall and by histologic subtype. Methods: The Los Angeles Ultrafines Study includes 45,012 participants aged ⩾50 years in southern California at enrollment (1995-1996) followed through 2017 for incident lung cancer (n = 1,770). We estimated historical residential ambient UFP number concentrations via land use regression and back extrapolation using PM2.5. In Cox proportional hazards models adjusted for smoking and other confounders, we estimated associations between 10-year lagged UFP (per 10,000 particles/cm3 and quartiles) and lung cancer overall and by major histologic subtype (adenocarcinoma, squamous cell carcinoma, and small cell carcinoma). We also evaluated relationships by smoking status, birth cohort, and historical duration at the residence. Measurements and Main Results: UFP was modestly associated with lung cancer risk overall (hazard ratio [HR], 1.03 [95% confidence interval (CI), 0.99-1.08]). For adenocarcinoma, we observed a positive trend among men; risk was increased in the highest exposure quartile versus the lowest (HR, 1.39 [95% CI, 1.05-1.85]; P for trend = 0.01) and was also increased in continuous models (HR per 10,000 particles/cm3, 1.09 [95% CI, 1.00-1.18]), but no increased risk was apparent among women (P for interaction = 0.03). Adenocarcinoma risk was elevated among men born between 1925 and 1930 (HR, 1.13 [95% CI, 1.02-1.26] per 10,000) but not for other birth cohorts, and was suggestive for men with ⩾10 years of residential duration (HR, 1.11 [95% CI, 0.98-1.26]). We found no consistent associations for women or other histologic subtypes. Conclusions: UFP exposure was modestly associated with lung cancer overall, with stronger associations observed for adenocarcinoma of the lung.

Imprisoning Intimacy: The Expanding Sites of Racialized-Gendered Carceral Violence

This study conceptualizes carceral violence to include the intimate sphere, highlighting a form of systemic racialized-gendered violence I term intimate carceral violence, which consists of two distinct violent effects of carcerality on relationships in Black communities: prisonized romance and coercive carceral care. I conducted qualitative interviews with 31 criminal-legal system–impacted Black women aged between 18 and 65 years in Southern California. Findings revealed that their romantic precarity included the challenge of finding partners due to the encroachment of the carceral state on Black communities. This study establishes how women engage in intimate carceral labor to mitigate their experiences of intimate carceral violence. I focus on the hidden work of managing an intimate partner’s emotions and behavior engendered by incarceration.

Pediatric Vaccination During the COVID-19 Pandemic.

The impact of the coronavirus disease 2019 pandemic on vaccination coverage, critical to preventing vaccine-preventable diseases, has not been assessed during the reopening period. Vaccine uptake and vaccination coverage for recommended vaccines and for measles-containing vaccines at milestone ages were assessed in a large cohort of children aged 0 to 18 years in Southern California during January to August 2020 and were compared with those in the same period in 2019. Differences in vaccine uptake and vaccination coverage (recommended vaccines and measles-containing vaccines) in prepandemic (January to March), stay-at-home (April to May), and reopening (June to August) periods in 2020 and 2019 were compared. Total and measles-containing vaccine uptake declined markedly in all children during the pandemic period in 2020 compared with 2019, but recovered in children aged 0 to 23 months. Among children aged 2 to 18 years, measles-containing vaccine uptake recovered, but total vaccine uptake remained lower. Vaccination coverage (recommended and measles-containing vaccines) declined and remained reduced among most milestone age cohorts ≤24 months during the pandemic period, whereas recommended vaccination coverage in older children decreased during the reopening period in 2020 compared with 2019. Pediatric vaccine uptake decreased dramatically during the pandemic, resulting in decreased vaccination coverage that persisted or worsened among several age cohorts during the reopening period. Additional strategies, including immunization tracking, reminders, and recall for needed vaccinations, particularly during virtual visits, will be required to increase vaccine uptake and vaccination coverage and reduce the risk of outbreaks of vaccine-preventable diseases.

Developing monitoring techniques for the invasive goldspotted oak borer (Coleoptera: Buprestidae) in California.

The goldspotted oak borer, Agrilus auroguttatus Schaeffer (Coleoptera: Buprestidae), is an invasive species that has colonized oak woodlands in southern California. To better define its seasonal flight activity, assist with forest and integrated pest management activities, and define the current distribution in California, an effective monitoring technique for A. auroguttatus is necessary. We assessed the efficacy of two colors of flight-intercept prism traps, the placement of these traps at three heights, and several commercially available lures [Manuka oil, Phoebe oil, and a green leaf volatile, (3Z)-hexenol] for monitoring the flight of adult A. auroguttatus. Landing rates and the densities of D-shaped emergence holes of A. auroguttatus adults were assessed on the lower stems of coast live oak, Quercus agrifolia Née, of varying size and crown health classes. Purple flight-intercept prism traps placed at heights of 3 m and 4.5 m caught significantly more female A. auroguttatus than green prism traps. In one experiment, males also responded at a significantly higher level to purple than to green prism traps placed at 3 m height. The addition of commercially available lures significantly enhanced male, but not female, A. auroguttatus trap catch when compared with unbaited control traps. There were no differences among male flight responses to the three lures. A. auroguttatus landing rates and emergence hole densities were significantly greater on the largest-diameter trees (>76.2 cm diameter at breast height) and on trees with severe crown thinning or complete crown collapse. The annual increment in emergence hole densities was also significantly greater on trees with severe crown thinning or complete crown collapse. In three trapping studies over multiple years in southern California, the adult flight period began as early as mid-May, peaked in mid-June to early July, and ended in early- to mid-September. To demonstrate the efficacy of the detection method for A. auroguttatus (unbaited purple traps at 3 m height), a delimitation survey conducted from 2009 to 2012 confirmed that the species was only present in San Diego Co., but that the distribution was expanding northward.

‘Hass’ avocado tree growth on four rootstocks in California. II. Shoot and root growth

We investigated the relationship between alternate cropping and shoot and root growth in mature ‘Hass’ avocado (Persea americana Mill.) trees growing on ‘Thomas’, ‘Topa Topa’, ‘Duke 7’, or ‘D9’ rootstocks over five years in Southern California. Shoot growth occurred during two distinct flushes each year: one in spring and one in late summer. Root growth occurred throughout the year, with higher rates during spring and summer but slower growth rates during shoot growth flushes. There was no effect of rootstock on shoot growth rate. There was no direct relationship between alternate bearing and shoot and root growth. It is possible that cropping affected shoot growth, with extensive shoot development occurring in a year with virtually no crop. The summer growth flush accounted for a greater proportion of the total shoot growth in years with light crop loads than in years with heavy crop loads. There were differences in root growth rate among rootstocks, but these relative differences varied among years. Root growth did not exhibit dormant periods as shoot growth did, but in general, root growth rate was greatest when soil temperatures were high and when shoots were not growing. This information gives us insight into the relative timing and relationships among growth events of avocado in Southern California and will help growers determine the optimal timing of cultural practices. Our results suggest that the best timing for fertilizing, spraying, and pruning is similar in trees growing on different rootstocks.

Estimation of developmental parameters for adult emergence of Gonatocerus morgani, a novel egg parasitoid of the glassy-winged sharpshooter, and development of a degree-day model

The effects of temperature on the development (egg–adult emergence) of Gonatocerus morgani Triapitsyn, a newly-described parasitoid of Homalodisca vitripennis (Germar), were determined at 14.8, 18.7, 23.5, 26.9, 28.7, 30.4, 32.8, and 33.8°C in the laboratory. Survival rate (percent adult emergence from parasitized host eggs) varied significantly among the experimental temperatures, with the highest (59%) and lowest (0%) occurring at 30.4 and 33.8°C, respectively. The survival rates (%) were fitted with a polynomial model to describe a temperature-dependent pattern. Developmental rates (1/d) across seven temperatures were fitted with the nonlinear Briere model, which estimated the lower threshold to be 8.06°C, the optimal temperature to be 29.22°C, and the upper threshold to be 33.49°C. A linear model fitted to developmental rates at 14.8–28.7°C indicated that 189.75degree-days above the lower threshold of 9.71°C were required to complete development. A simulation model of G. morgani adult emergence was constructed to predict daily counts over the entire range of constant temperatures by incorporating the survival rate model, the Briere model, and the Weibull model. In outdoor validation, a degree-day model for predicting adult emergence showed ⩽2d differences between prediction and observation. Based on the observed temperature requirement, the insect could complete thirteen to sixteen generations per year in southern California, depending on weather and location.

Control of Exotic Annual Grasses to Restore Native Forbs in Abandoned Agricultural Land

Exotic annual grasses are a major challenge to successful restoration in temperate and Mediterranean climates. Experiments to restore abandoned agricultural fields from exotic grassland to coastal sage scrub habitat were conducted over two years in southern California, U.S.A. Grass control methods were tested in 5 m2 plots using soil and vegetation treatments seeded with a mix of natives. The treatments compared grass‐specific herbicide, mowing, and black plastic winter solarization with disking and a control. In year two, herbicide and mowing treatments were repeated on the first‐year plots, plus new control and solarization plots were added. Treatments were evaluated using percent cover, richness and biomass of native and exotic plants. Disking alone reduced exotic grasses, but solarization was the most effective control in both years even without soil sterilization, and produced the highest cover of natives. Native richness was greatest in solarization and herbicide plots. Herbicide application reduced exotics and increased natives more than disking or mowing, but produced higher exotic forb biomass than solarization in the second year. Mowing reduced grass biomass and cover in both years, but did not improve native establishment more than disking. Solarization was the most effective restoration method, but grass‐specific herbicide may be a valuable addition or alternative. Solarization using black plastic could improve restoration in regions with cool, wet summers or winter growing seasons by managing exotic seedbanks prior to seeding. While solarization may be impractical at very large scales, it will be useful for rapid establishment of annual assemblages on small scales.

Insolation forcing of Holocene climate change in Southern California: a sediment study from Lake Elsinore

Lake Elsinore is the largest natural lake in Southern California. As such, the lake provides a unique opportunity to investigate terrestrial climate on timescales otherwise underrepresented in the region’s terrestrial environment. In November 2003, three ∼10 m drill cores were extracted from the depocenter region of Lake Elsinore. These drill cores, spanning the past 9,500–11,200 calendar years, represent the first complete Holocene record of terrestrial climate from Southern California. In this paper, we focus on two adjacent, depocenter cores (LEGC03-2 and LEGC03-3), which have been correlated to develop a single composite core. Twenty-two AMS 14C dates on bulk organic matter and one cross-correlated exotic pollen age constitute the composite core’s age control. Several methods of analysis, including mass magnetic susceptibility, % total organic matter, % total carbonate, % HCl-extractable Al, and total inorganic P are used to infer climate for the past 9,500 calendar years in Southern California. Together, these data indicate a wet early Holocene followed by a long-term drying trend. Recent lake-level reconstructions from Owens Lake and Tulare Lake support our contention for a wetter-than-today early Holocene. Lacustrine sediments from the Mojave Desert also support our conclusions. We suggest that over the duration of the Holocene changing summer/winter insolation alters the region’s long-term hydrologic balance through its modulation of atmospheric circulation and its associated storm tracks. Minimum early Holocene winter insolation and maximum summer insolation act together to increase the region’s total annual precipitation by increasing the frequency of winter storms as well as enhancing the magnitude and spatial extent of the North American monsoon, the frequency of land-falling tropical cyclones in Southern California, and regional convective storms, respectively. Gradual decreases in summer insolation and increases in winter insolation produce the opposite effect with maximum drying in the late Holocene.

Landscape restoration in southern California forblands: Response of abandoned farmland to invasive annual grass control

A large-scale experiment using 1-ha plots was done to control invasive Mediterranean annual grasses, primarily Bromus spp., in farmlands abandoned for 20 years in southern California. Treatments were a grass-specific herbicide, and herbicide plus dethatching. Dethatching was done to improve the contact of herbicide with newly growing grass seedlings, and to remove litter that may potentially affect germination of native annuals. Native annuals had increased richness in response to grass control, but had low cover in all but two of six years when precipitation was adequate. Dethatching did not improve forb response. Two exotic species of Erodium were the greatest beneficiaries of exotic grass control, but the positive response of native forbs in spite of Erodium dominance suggests a competitive hierarchy of less intense interaction between the native forbs and Erodium than between native forbs and exotic grasses. After five years, grasses began to recover from the herbicide treatments, indicating the need for periodic management of exotic grasses to maintain richness and cover of native forbs. Shrubs that occur on adjacent hills did not recolonize during these six years, suggesting that the valley bottoms may have always been forblands rather than shrublands. The study shows that restoration can be used to rediscover the former vegetation of long-disturbed landscapes.

Scaling and precursor motifs in earthquake networks

A measure of the correlation between two earthquakes is used to link events to their aftershocks, generating a growing network structure. In this framework one can quantify whether an aftershock is close or far, from main shocks of all magnitudes. We find that simple network motifs involving links to far aftershocks appear frequently before the three biggest earthquakes of the last 16 years in Southern California. Hence, networks could be useful to detect symptoms typically preceding major events.

Understanding variability in time spent in selected locations for 7-12-year old children.

This paper summarizes a series of analyses of clustered, sequential activity/location data collected by Harvard University for 160 children aged 7-12 years in Southern California (Geyh et al., 2000). The main purpose of the paper is to understand intra- and inter-variability in the time spent by the sample in the outdoor location, the location exhibiting the most variability of the ones evaluated. The data were analyzed using distribution-free hypothesis-testing (K-S tests of the distributions), generalized linear modeling techniques, and random-sampling schemes that produced "cohorts" whose descriptive statistical characteristics were evaluated against the original dataset. Most importantly, our analyses indicate that subdividing the population into appropriate cohorts better replicates parameters of the original data, including the interclass correlation coefficient (ICC), which is a relative measure of the intra- and inter-individual variability inherent in the original data. While the findings of our analyses are consistent with previous assessments of "time budget" and physical activity data, they are constrained by the rather homogeneous sample available to us. Owing to a general lack of longitudinal human activity/location data available for other age/gender cohorts, we are unable to generalize our findings to other population subgroups.

Shakespeare’s Grave: The British Fiction of Hollywood

All sorts of English oddities turn up in Hollywood. P. G. Wodehouse, The Old Reliable (51) I have a favorite quote about L.A., by William Shakespeare. He said: This other Eden, demi-Paradise,/This precious stone set in the silver sea,/This earth, this realm, this-Los L.A. Story Is Shakespeare buried in Hollywood? Steve Martin's 1991 film L.A. Story asserts that he is, explaining that Shakespeare wrote Hamlet, Part VIII: The Revenge during his final years in Southern California and revealing his tomb in Cemetery (right behind Paramount Studios). The scene familiarly lampoons the cultural acquisitiveness and ignorance that might allow an American to believe that Shakespeare was buried not far from the elaborate graves of Douglas Fairbanks and Tyrone Power, both of which are adorned with Goodnight, sweet prince. But Martin is not the first to locate Shakespeare's grave in Los Angeles. Aldous Huxley does it too, in his After Many a Summer Dies the Swan (1939). On first arriving in L.A., his main character, the scholar Jeremy Pordage, is taken to a cemetery, the Beverly Pantheon (based on Forest Lawn), where he encounters. The Tiny Church of the Poet--a miniature reproduction of Holy Trinity at Stratford-on-Avon, complete with Shakespeare's tomb and a twenty-four-hour service of organ music played automatically by the Perpetual Wurlitzer and broadcast by concealed loud speakers all over the cemetery. (10) In Evelyn Waugh's The Loved One (1948), which focuses more exclusively on Forest Lawn (here called Whispering Glades), Shakespeare is cited for frankly commercial purposes, as a mortuary hostess touts Before-Need Arrangements by saying, Hamlet so beautifully writes: 'Know that death is common; all that live must die' (53). In several other novels of by writers, Shakespeare (or another eminent representative of the literary tradition) makes an appearance--comically out of place and generally associated with mortality. As Stephen Greenblatt notes, Shakespeare has come to represent 'culture' as a whole (1), and the theme associated with Shakespeare's grave in literature often invokes other canonical texts as representative of an Anglo-European tradition to which Americans have only attenuated access (for example, Shelley functions in Huxley's Ape and Essence in much the same way Shakespeare functions in After Many a Summer Dies the Swan and Brave New World). The recur rent trope of Shakespeare's California grave encapsulates an important theme in the fiction of Hollywood: is the site of conflicts between high and low culture, between literature and film, and between tradition and American cultural acquisitiveness. (1) fiction is a regional literature of sorts, but unlike most regional literatures it is written almost entirely by outsiders, by people not native to the region. The literature of grew out of an unprecedented collision of artistic media that came about with the development of talking pictures in the late 1920s. Established novelists, journalists, and playwrights from England and the East Coast of the United States found themselves participating in the California dream as they headed west for the lucrative living supposedly available to those skilled with the written word. Some became successful screenwriters, some merely marketed their novels or plays for screen treatment, others fled in disgust or after failing in the film industry. But many of this group incorporated their experiences in into works of fiction. The term Hollywood novel commonly evokes a handful of works: Nathanael West's The Day of the Locust, Fitzgerald's unfinished The Last Tycoon, and works by John O'Hara, Horace McCoy, and Budd Schul berg. But there are many more established authors who, after coming west to work in the movies, wrote books set in or Southern California, among them members of the so-called British colony. …

Triggering of 1812 Santa Barbara Earthquake by a Great San Andreas Shock: Implications for future seismic hazards in southern California

We study the evolution of the stress field over the last 200 years in southern California using the stress buildup associated with major faults and stress drops associated with great earthquakes. In this report we calculate the change in the Coulomb Failure Function (ΔCFF) associated with the great Wrightwood earthquake of Dec. 8, 1812 on the San Andreas fault for the region near Santa Barbara that experienced a large shock 13 days later. The rupture length constrained by paleoseismic data is used for the Wrightwood earthquake of 1812; a uniform displacement of 3.5 m from the surface to seismogenic depths is assumed. The geologic setting and focal mechanisms of earthquakes in the Santa Barbara region are dominated by thrust, left‐lateral strike‐slip faulting and combinations of the two. For our preferred rupture model of the earthquake of Dec. 8 the Santa Barbara shock of Dec. 21, 1812 occurred in a region of +0.01 to +0.1 MPa ΔCFF for reasonable fault orientations, indicating that it may have been advanced by years to decades and triggered by the great San Andreas earthquake 13 days earlier. We also calculate ΔCFF on typical kinds of faults in southern California for a future candidate great earthquake along the San Bernardino and Coachella Valley segments of San Andreas fault. This earthquake produces large positive values of ΔCFF for shallow‐dipping thrust faults beneath the greater Los Angeles area and for NW‐trending right‐lateral strike‐slip faults in three regions. This suggests that shocks of magnitude similar to the M 7.1 1812 Santa Barbara earthquake could be triggered by the next great event on the southern San Andreas fault.

Increasing Sensitivity of Blood Pressure to Dietary Sodium and Potassium With Increasing Age: A Population Study Using Casual Urine Specimens

In a population of 887 men and 1159 women aged 40 to 89 years in southern California, age adjusted systolic and diastolic blood pressures correlated significantly with sodium/potassium ratios estimated from casual urine samples. The relationship was apparent over the whole range of blood pressures and urinary electrolyte excretions. An age gradient was apparent for systolic pressure in both men and women, the regression slope for blood pressure versus sodium/potassium ratio being steeper with increasing age. The regression slope overall was approximately 4 mm Hg systolic and 1 mm Hg diastolic pressure increase per unit increase in sodium/potassium (mmol/mmol) ratio. The use of casual urine samples in assessing the blood pressure and sodium/potassium relationship should not be prematurely dismissed. Evidence from this and other studies suggests the relationship between blood pressure and electrolyte intake in the population may be more dynamic than previously believed, and also more marked in the old, who are at the greatest risk for cardiovascular disease. A reduction in the age-related increase in blood pressure has considerable implications for the prevention of cardiovascular disease.

Rotavirus gastroenteritis in southern California.

The epidemiology of rotavirus infections in Southern California was analyzed over a three year period, from January 1, 1981 through December 31, 1983. Data was available from patients seen at the University of California Irvine Medical Center (UCIMC), in addition to referral testing provided to the community in Orange County. Over the 3 yr period the laboratory performed 1172 rotavirus assays. Out of these, 345 were positive for an overall positive rate of 29.4%. The 643 stool specimens from UCIMC corresponded to 508 patients, of which 31.1% (158/508) were positive for rotavirus. The majority of patients with a positive rotavirus test were under 1 yr of age (117/158), with only ten cases found in the 2-15 yr old group. The distribution of the positive rotavirus tests was similar for the female and male population. Approximately 70% of the positive results occur during October through December, with the month of November having the highest incidence. The distribution of positive rotavirus tests did not appear to correlate with either the coldest or the driest month of the year in Southern California.

Seasonal Variation in Number of Eggs Laid by Culiseta Incidens (Diptera: Culicidae)1

Culiseta incidens egg rafts collected from the field in the spring contained more eggs than did rafts taken at other times of the year in southern California, USA. Evidence presented elsewhere indicates that females emerging in the spring develop at lower temperatures, are subjected to less crowding during development, and thus are larger than females emerging at other times of the year. Data are given on fecundity and fertility of Cs. incidens and Cs. inornata .

Body Water Content in Marine Birds

Total body water (TBW) in adult birds averages approximately 60% of body weight, regardless of bird size (Skadhauge 1981:3). Voluminous data on land and aquatic birds have been obtained using two techniques: oven drying to constant weight and isotope or dye dilution. These techniques yield similar results (Degen et al. 1981). However, Ruch and Hughes (1975) and Walter and Hughes (1978), using isotope dilution, found very high values of TBW of 79% and 88%, respectively, in age-unspecified (presumably adult) Glaucous-winged Gulls (Larus glaucescens). They postulated that larger TBW volume may be of adaptive significance to marine birds since larger relative volume would buffer the impact of salt load on the concentrations of body fluids (Walter and Hughes 1978). At that time, with the exception of one tern species (see Table 1), their data were apparently the only published values of TBW for marine birds. A high proportion of body water occurs in aquatic invertebrates (Prosser 1973:7). Documenting such similar occurrence in marine birds would be of broad interest, particularly because it would open the question of how bird composed of 80% or more body water could remain functional flying organism. Young birds do have TBW approximately 80%; however, this decreases with age, reaching adult levels at about fledging (e.g., Dunn 1975, Ricklefs and White 1981, Mahoney and Jehl 1982). In this note we present and synthesize data from 22 species of marine and aquatic birds to test whether high body water may be a general phenomenon among birds which live in marine environment (Walter and Hughes 1978). A review of the published data on TBW of birds was published by Skadhauge (1981), and Williams et al. (1982) have recently provided extensive data on water content of eggs and hatchlings in variety of seabirds. Most of our data were obtained from healthy (except where otherwise noted) adult birds that were freshly-collected over the course of year in southern California or at Mono Lake, Mono Co., Ca., hypersaline lake where total dissolved solids approximate 85-90%0. We also used some birds found freshly-dead because our earlier studies revealed no difference in body water content of birds freshly-dead and those collected (see data for Eared Grebe, Podiceps nigricollis, in Table 1). We weighed each bird after removing its stomach contents, opened the body cavity to insure complete desiccation and dried the carcass to constant weight in drying oven at 800C. Determining TBW this way does not correct for differences in body fat or possible loss of volatile fats in the drying process. A high percentage of fat would tend to underestimate TBW; loss of volatile fatty acids would slightly overestimate TBW. The errors in each case are small, and tend to cancel each other.

Nutrient gain from wet and dry atmospheric deposition and rainfall acidity in southern California chaparral.

Ionic concentration and annual deposition of NO -3 -N, NH +4 -N, Ca2+, and Mg2+ from bulk precipitation and dry atmospheric deposition were studied for one year in southern California. Data were collected from an inland chaparral site at 1,300 m elevation, 75 km from the coast. The annual depositions of NO -3 -N and NH +4 -N amounted to 96.3 and 56.0 mg m-2 ground area yr-1, respectively. The corresponding values for calcium and magnesium ions were 207.4 and 57.4 mg m-2 yr-1. The average pH of rainwater was 3.74 (range 3.37 to 4.75), thus documenting acid rain for an inland site in California, distant from urban sources of air contamination. An estimate of nitrogen gains and losses indicated that the time between recurrent chaparral fires should be about 60 years in order to maintain a balanced nitrogen budget.

"SEX-RATIO" TRAIT, SEX COMPOSITION, AND RELATIVE ABUNDANCE IN DROSOPHILA PSEUDOOBSCURA.

A considerable number of theoretical and laboratory studies of segregation distortion systems have provided insight into their biological consequences (see Zimmering et al. [1970], or Crow [1979] for a review). Yet these studies have provided few clues into the behavior of such systems in natural populations. Sex-ratio trait (SR) is particularly interesting, not only as a naturally occurring segregation distortion system, but also for its effects on the proportion of females in the offspring of SR males and the consequent effects on the sex composition of the population and on population growth. The trait in Drosophila pseudoobscura is associated with three non-overlapping inversions of the X-chromosome. Males carrying SR produce progenies consisting almost entirely of females. The presence of SR in a female, whether heterozygous or homozygous, has no effect on the sex composition of her progeny. The system is a widely occurring polymorphism in natural populations of D. pseudoobscura, reaching gene frequencies as high as 0.3 near the boundary of Arizona and Mexico. Its frequency declines both with increasing altitude and latitude, and it disappears at about the latitude of northern California (Sturtevant and Dobzhansky, 1936). The frequency of SR exhibits wide seasonal fluctuations in some localities (Dobzhansky, 1943), but aside from this seasonal cycle, it was found to be stable over a period of 20 years (Dobzhansky, 1958). Although SR is apparently held in equilibrium in many natural populations, in population cages it rapidly declines in frequency (Wallace, 1948; Anderson, 1974). In Wallace's experimental populations, SR was rapidly eliminated from the 25 C cages and dropped below a frequency of 0.1 in the cages maintained at 16.5 C. These results appear to conflict with the observations on natural populations: SR is present at higher temperatures (low altitudes and latitudes) and absent in regions characterized by lower temperatures. In this study, we analyze the relationships among temperature, the frequency of the SR trait, the frequency of females, and the frequency of Drosophila pseudoobscura in a mixed species Drosophila population studied for several years in Southern California.