The Central San Joaquin Valley Area Health Education Center

With federal financial support, an area health education center was established in the central San Joaquin Valley of California. The center is a cooperative health sciences education and health care program organized by the University of California and some of the educational and health care institutions of the valley. The center''s goals include providing and improving primary health care education, and improving the distribution of health personnel. These goals are achieved through the cooperative development of a number of independent and interdependent activities. An extensive evaluation of the Area Health Education Center has shown that it is a highly effective program.     

Response of Acala cotton to nitrogen rates in the San Joaquin Valley of California

The responses of Acala cotton (Gossypium hirsutum L.) in California to a range of applied nitrogen (N) treatments were investigated in a 5-year, multisite experiment. The experiment's goals were to identify crop growth and yield responses to applied N and provide information to better assess the utility of soil residual N estimates in improving fertilizer management. Baseline fertilizer application rates for the lowest applied N treatments were based on residual soil nitrate-N (NO3-N) levels determined on soil samples from the upper 0.6 m of the soil collected prior to spring N fertilization and within 1 week postplanting each year. Results have shown positive cotton lint yield responses to increases in applied N across the 56 to 224 kg N/ha range in only 41% (16 out of 39) of test sites. Soil NO3-N monitoring to a depth of 2.4 m in the spring (after planting) and fall (postharvest) indicate most changes in soil NO3- occur within the upper 1.2 m of soil. However, some sites (those most prone to leaching losses of soluble nutrients) also exhibited net increases in soil NO3-N in the 1.2- to 2.4-m depth zone when comparing planting time vs. postharvest data. The lack of yield responses and soil NO3-N accumulations at some sites indicate that more efforts should be put into identifying the amount of plant N requirements that can be met from residual soil N, rather than solely from fertilizer N applications.     

Early pregnancy agricultural pesticide exposures and risk of gastroschisis among offspring in the San Joaquin Valley of California

Background: Prevalence of gastroschisis has inexplicably been increasing over the past few decades. Our intent was to explore whether early gestational exposures to pesticides were associated with risk of gastroschisis. Methods: We used population‐based data, accompanied by detailed information from maternal interviews as well as information on residential proximity to a large number of commercial pesticide applications during early pregnancy. The study population derived from the San Joaquin Valley of California ( ). Cases were 156 infants/fetuses with gastroschisis and controls were 785 infants without birth defects. Results: Among 22 chemical pesticide groups analyzed, none had an elevated odds ratio with an associated confidence interval that excluded 1.0, although exposure to the triazine group showed borderline significance. Among 36 specific pesticide chemicals analyzed, only exposure to petroleum distillates was associated with an elevated risk, odds ratio = 2.5 (1.1–5.6). In general, a substantially different inference was not derived when analyses were stratified by maternal age or when risk estimation included adjustment for race/ethnicity, body mass index, folic acid supplement use, and smoking. Conclusion: Our study rigorously adds to the scant literature on this topic. Our a priori expectation was that we would observe certain pesticide compounds to be particularly associated with young age owing to the disproportionate risk observed for young women to have offspring with gastroschisis. We did not observe an exposure profile unique to young women. Birth Defects Research (Part A), 100:686–694, 2014. © 2014 Wiley Periodicals, Inc.     

Effects of winter temperatures on the sex ratios ofAphytis melinus [Hym.: Aphelinidae] in the San Joaquin Valley of California

Laboratory bioassays of overwintering field populations of the California red scale parasitoidAphytis melinus DeBach showed a shift in sex ratio of F₁ progeny after prolonged exposure to winter temperatures in Tulare County, California. In 7 of 8 tests, short-term winter field exposure (<75 days) did not result in a significant male bias in sex ratios of F₁ progeny when compared to sex ratios observed in laboratory cultures maintained at 27°C. Long term exposure (109–139 days), however, resulted in significantly (P<0.05) higher male bias in F₁ sex ratios in 5 of 6 tests. These results from field populations ofA. melinus agree with conclusions of low temperature laboratory tests onAphytis species (lingnanensis, melinus) by other workers. Mention of a proprietary or commercial product in this paper does not constitute an endorsement of this product by the University of California.     

Biological control of Pacific mites and Willamette mites in San Joaquin Valley vineyards: part III. Role of tydeid mites

In the absence of spider mites, tydeids (Pronematus anconaiBaker and Pronematus ubiquitus [Mc Gregor ]) may serve as alternate prey to maintain good numbers of the predatory mite, Metaseiulus occidentalis (Nesbitt ) (Acarina, Phytoseiidae), late in the season. This late-season predator and alternate prey relationship is necessary to stabilize Pacific mite populations and perpetuate balance in San Joaquin Valley vineyards. Thriving laboratory colonies of tydeids were reared on a diet of windblown pollens, including cattail pollen (Typha sp., Typhaceae) and bottlebrush pollen (Melaleuca sp., Myrtaceae).M. occidentalis was successfully reared on a diet of tydeids and ovipositing predator females were obtained. In addition, pollen dusted on grapevines significantly increased both tydeid and indirectly M. occidentalis populations late in the season. These studies suggest that artificially disseminating cattail pollen or manipulating good pollen producing flora in and around vineyards may be used to correct situations where Pacific mites have become serious pests.     

Genetic study of the Paleolithic and Neolithic Southeast Asians.

DNA samples were extracted from six prehistoric human remains, found on the Malay Peninsula, dating to the Paleolithic and the Neolithic periods. Nucleotide sequences of mitochondrial DNA were determined by the polymerase chain reaction-direct sequencing method. A phylogenetic tree between prehistoric and present humans was constructed based on the nucleotide sequence data. Mitochondrial DNA phylogenetic relationships and ethnoarchaeological evidence suggest that there is a continuity beetween the pre-Neolithic humans and the present Semang and that the Neolithic humans in this area might be an ancestral group of the Senoi.     

Vitamin D state of Asians living in Pakistan.

Asians living in Pakistan have serum 25-hydroxycholecalciferol concentrations which are well within the normal range and significantly higher than in Asians resident in Britain. Clearly, Asians can maintain an adequate vitamin D state given an abundant supply of ultraviolet light, and the expression of vitamin D deficiency is an environmental and not a genetically determined characteristic. The risk of an Asian developing vitamin D deficiency increases after migration to Britain. The most efficient way to treat this is by supplementation with vitamin D.     

Maternal footprints of Southeast Asians in North India

We have analyzed 7,137 samples from 125 different caste, tribal and religious groups of India and 99 samples from three populations of Nepal for the length variation in the COII/tRNA(Lys) region of mtDNA. Samples showing length variation were subjected to detailed phylogenetic analysis based on HVS-I and informative coding region sequence variation. The overall frequencies of the 9-bp deletion and insertion variants in South Asia were 1.9 and 0.6%, respectively. We have also defined a novel deep-rooting haplogroup M43 and identified the rare haplogroup H14 in Indian populations carrying the 9-bp deletion by complete mtDNA sequencing. Moreover, we redefined haplogroup M6 and dissected it into two well-defined subclades. The presence of haplogroups F1 and B5a in Uttar Pradesh suggests minor maternal contribution from Southeast Asia to Northern India. The occurrence of haplogroup F1 in the Nepalese sample implies that Nepal might have served as a bridge for the flow of eastern lineages to India. The presence of R6 in the Nepalese, on the other hand, suggests that the gene flow between India and Nepal has been reciprocal.     

Selenium in animal nutrition: The Oregon and San Joaquin Valley (California) experiences—Examples of correctable deficiencies in livestock

White muscle disease and other selenium deficiency syndromes, once extremely common in young calves and lambs in Oregon, especially in the areas of volcanic origin east of the Cascade mountain range, prompted extensive investigations in the Oregon Agricultural Experiment Station that resulted in the implementation of large-scale selenium supplementation programs. Although selenium deficiency in livestock is consequently now rare in Oregon, selenium-deficient soils and attendant selenium deficiency conditions have been reported near the Kesterson Wildlife Refuge in the Northern part of the San Joaquin Valley, California, where, paradoxically, selenium toxicity in wildfowl, nesting near evaporation ponds, occurred and attracted wide attention. This review cites studies which explain why there is no evidence of selenium toxicity in livestock, but some selenium deficiency on the east side of the San Joaquin Valley. They also show that there is no threat to the food supply owing to excessive selenium in this area and that the consumption of meat and milk from the herds would not exceed the safe range of selenium for humans.     

Seasonal movement and distribution of the grape mealybug (Homoptera: Pseudococcidae): developing a sample program for San Joaquin Valley vineyards

The grape mealybug, Pseudococcus maritimus (Ehrhorn), is an important pest of table grapes in California's San Joaquin Valley. The mealybug causes direct damage by infesting grape bunches, resulting in very low economic injury levels. To develop a sampling program to help growers predict damage and make control decisions, we destructively sampled six entire grapevines each month to determine mealybug abundance and within-vine distribution. These absolute counts were then used to evaluate several relative sampling methods: sticky tape barriers on canes, excised spur samples, standard-sized pieces of bark, timed counts, and nondestructive counts on spurs. At midseason we sampled additional vines to correlate mealybug numbers with economic damage at harvest. Finally, mealybug life stages and natural enemies were recorded throughout the study. Timed 5-min counts show the strongest correlation with total mealybug numbers, and a simple count of mealybugs on three spurs per vine at midseason is the best predictor of economic damage. Mealybugs completed approximately equals 2.5 generations in 1998. Comparison to data on mealybug development suggests that exceptionally long growing seasons could exacerbate infestations by allowing the completion of a third generation. No mealybugs were found on bunches before early August, when second-generation crawlers moved out of the bark. Grape bunches that touched old wood had significantly higher damage and mealybug densities. The majority of mealybugs were always found in protected locations (under the bark of the trunk, spurs or canes), indicating the need for chemical or biological controls that can penetrate these refugia.     

Hematologic values of the endangered San Joaquin kit fox, Vulpes macrotis mutica

Between 1981 and 1982 blood samples were collected from 64 adult San Joaquin kit foxes, Vulpes macrotis mutica, in western Kern County, California. The goal of the study was to establish normal blood values for this endangered species, and to determine whether changes in them could be used to assess the possible effects of petroleum developments on these foxes. None of the values differed significantly between the sexes, or between foxes sampled in developed habitats compared with foxes sampled in undisturbed habitats. Mean values of Hb, MCH, MCHC, and WBC counts differed significantly between summer and winter. Average hematological characteristics were: RBC, 8.4 X 10(6)/microliter; Hb, 14.5 g/dl (summer), 15.6 g/dl (winter); PCV, 46.9%; MCV, 56.3 fl; MCH, 17.8 pg (summer), 18.4 pg (winter); MCHC, 31.2 g/dl (summer), 33.2 g/dl (winter); and WBC, 6,200/microliter (summer), 7,500/microliter (winter). Comparisons of hematological data for kit foxes, coyotes (Canis latrans), and wolves (Canis lupus) confirmed a previously published observation that within mammalian families RBC counts are correlated inversely with body weight, and that MCV is correlated directly with body weight.     

Gene flow among San Joaquin kit fox populations in a severely changed ecosystem

The San Joaquin kit fox (Vulpes macrotis mutica) was once ubiquitous throughout Californias San Joaquin Valley and its surrounds. However, most of its habitat has been lost to irrigated agriculture, urban development, and oil fields. The remaining foxes are concentrated in six areas, although there are several small pockets of foxes throughout the Valley. To help conserve kit foxes, we sought an ecological understanding of the level of genetic variation remaining in these locations and the extent of gene flow among them. We collected tissue from 317 kit foxes from 8 sites and estimated genetic variability in and gene flow among sites using data from 8 polymorphic, microsatellite markers. We found no differences in both observed and expected heterozygosity between locations using Bonferonni corrected paired t-tests. We found differences in mean number of alleles per locus, even after we used Monte Carlo simulations to adjust for sample size differences. Population subdivision was low among sites (F_st=0.043), yet a matrix of pairwise F_st values was correlated with a matrix of pairwise geographic distances. An assignment test classified only 45% of the individuals to the site where they were captured. Overall, these data suggest that kit fox dispersal between locations may still maintain genetic variation throughout most of the areas we sampled.