Isla San Pedro Nolasco as a Late Miocene intrusive record at the eastern margin of the Gulf of California:Insights from geological,geochemical and geochronological studies

Isla San Pedro Nolasco(ISPN)is a structural high bounded by inactive dextral oblique-slip faults in the east-central part of the Gulf of California rift zone and is composed of intrusive rocks not exposed on other Gulf of California islands.Here we present the reconnaissance results from geological mapping,as well as first geochemical and geochronological data for the ISPN intrusive complex.The intrusive rocks compose a sheet-like body of intermediate and felsic composition intruded by an intermediate and acidic dike swarm.All intrusive rocks(host and dikes)range in age from ca.9 Ma to 10 Ma(^(40)Ar/^(39)Ar)and show a hydrous ferromagnesian mineral association(amphibole and biotite)with a calc-alkalic and transitional affinity.This hydrated mineralogical association has not been recognized in the coeval rocks along the onshore western margin of the North American plate(coastal Sonora).However,such hydrous mineralogical association is found in the coeval rift transitional volcanic rocks from the Baja California Microplate at Santa Rosalía and Bahía de LosÁngeles–Bahía de LasÁnimas.The ISPN continental block,at least 40 km long,has been pulled apart by transtensional faulting of the late Miocene Gulf of California shear zone before the westward migration of the North America-Pacific plate boundary at ca.3–2 Ma.Eventually,ISPN became isolated as an island during the late Miocene flooding of the Gulf of California seaway.

An Approach to Assessment to Population of the Brown Shrimp, <i>Farfantepenaeus californiensis</i>(Holmes, 1900), as a Management Fisheries Tool in the Southeastern Gulf of California

The brown shrimp, Farfantepenaeus californiensis, is the most important shrimp species in the Mexican Pacific coastal fisheries, with annual yields averaging 20,000 metric tons. The Mexican state of Sinaloa has the largest Mexican fleet of shrimp trawlers (736 boats) with annual landings of 7000 tons of brown shrimp on average. The status of the brown shrimp fishery was assessed using commercial catch and effort data of the Sinaloa shrimp trawl fleet over 16 years, from 1995 to 2011. We developed a biomass dynamic Schaefer model and used resampling techniques to analyze the catch-per-unit effort (CPUE) of the trawl brown shrimp fishery in the southeastern Gulf of California,Mexico. To ascertain robustness of our conclusions, two hypotheses were tested: observation and process error. Explicitly accounting for observation errors produced the best model fit to available data than including process errors. We identified several sources of observation error, for example discriminating fishing effort by species, changes in catch ability and misreported catch. The brown shrimp fishery showed symptoms of overfishing, although catch reported in the last fishing season considered in the analyses seems to indicate a rapid recovery of the stock. Finally, we predicted for the 2011-12 fishing season a catch of 9630 tonsof brown shrimp.

Management for the White Shrimp (Litopenaeus vannamei) from the Southeastern Gulf of California through Biomass Models Analysis

Samples taken during the closed fishing seasons from 1992 to 2010 were analyzed at sea. These data along with the landing records for the fishing periods from 1992-1993 to 2009-2010 were used to allow the situation of Litopenaeus van-namei from the coasts of Sinaloa and Nayarit to be analyzed by means of stochastic models and by a graphic approach for the surplus biomass. Using the catch from 1993-1994 as a reference point and comparing this to the 2008-2009 catch revealed a stock decrease of about 65%. By taking into account the percentage contribution to total shrimp land-ings, these changes showed a decrease from 76% to 12%. There were changes between 2000 and 2001 when the fleet grew by 50%. Considering a 3600 t maximum sustained yield (MSY) in the series 1992-2010, 50% of the reports are lower. It is necessary to recover the stock.

Remote Monitoring of Vegetation Managed for Dust Control on the Dry Owens Lakebed, California

A monitoring program was developed to assess the cover of saltgrass managed for dust control on the saline dry Owens Lake. Although the original intent was to manage the vegetation as total cover that included green and senesced leaf and stem material, aged leaves that make up a large proportion of total cover were not differentiable spectrally from the background salt and lakebed. Hence, greenness-based indices were explored for detection of plant recruitment. Since all plant cover begins as green and growing, greenness indices provide a measure of all future cover whether living or senesced. The criteria for judging compliance were changed so that spatially variable vegetation cover measured as a milestone will need to be met in the future. A derivative of NDVI, NDVIx, calculated using scene statistics, proved highly accurate, to about 0.001 of this index and with an average signal to noise ratio of 64. This high level of accuracy allowed detection of small changes in vegetation growth and vigor. Performance according to the benchmark-as-par standard was determined through combined use of cumulative distribution functions and derivative maps.

Remote Monitoring of Surfaces Wetted for Dust Control on the Dry Owens Lakebed, California

Extensive dust control on the dry Owens Lake mainly uses constructed basins that are flooded with shallow depths of fresh water. This dust control is mandated by law as a minimum percent of the area of each individual wetting basin. Wetted surfaces are evaluated for area and degree of wetness using the shortwave infrared (SWIR) band of Landsat TM, or similar earth observation satellite sensor. The SWIR region appropriate for these measurements lies within the electromagnetic spectrum between about 1.5 and 1.8 μm wavelengths. A threshold value for Landsat TM5 band 5 reflectance of 0.19 was found to conform with surfaces having a threshold for adequate wetting at a nascent point where rapid drying would occur following loss of capillary connection with groundwater. This threshold is robust and requires no atmospheric correction for the effects of aerosol scatter and attenuation as long as the features on the image appear clear. Monthly monitoring of surface wetting has proven accurate, verifiable and repeatable using these methods. This threshold can be calibrated for any Earth observation satellite that records the appropriate SWIR region. The monitoring program is expected to provide major input for the final phase of the dust control program that will have a focus to conserve water and resources.

Breeding Status, Nesting Densities ＆ Diet Trends of Two Endangered California Least Tern Colonies

The California least tern （Sternula antillarum browni） is an endangered species. The two largest colonies of this bird species in the San Francisco Bay, California, USA, are located 23 km apart at Alameda Point and Hayward Regional Shoreline. The Alameda Point colony, on the former Naval Air Station, Alameda, has grown at an average rate of 9.2% per year since its discovery in 1976 and has a nesting density ranging from 1-153 nests per ha. Long-term breeding success at Alameda has averaged 0.86 fledglings per breeding pair. Least tems began appearing in 2003, at an island in Hayward enhanced with substrate mediums and social attraction devices. Successful breeding attempts have been observed at the Hayward colony since 2006. The Hayward colony has grown at an average rate of 51.5% per year, has a nesting density ranging from 33-333 nests per ha and long-term breeding success average of 0.87 fledglings per breeding pair. Dropped fish have been collected from both colonies, and silversides （family Atherinopsidae） are the dominant prey. Alameda terns forage on a greater variety of species than the Hayward terns. The regression results indicate the importance of Northern anchovy （Engraulis mordax） to the breeding success of the Alameda colony.

Monitoring of Net Primary Production in California Rangelands Using Landsat and MODIS Satellite Remote Sensing

In this study, we present results from the CASA (Carnegie-Ames-Stanford Approach) model to estimate net primary production (NPP) in grasslands under different management (ranching versus unmanaged) on the Central Coast of California. The latest model version called CASA Express has been designed to estimate monthly patterns in carbon fixation and plant biomass production using moderate spatial resolution (30 m to 250 m) satellite image data of surface vegetation characteristics. Landsat imagery with 30 m resolution was adjusted by contemporaneous Moderate Resolution Imaging Spectroradiometer (MODIS) data to calibrate the model based on previous CASA research. Results showed annual NPP predictions of between 300 - 450 grams C per square meter for coastal rangeland sites. Irrigation increased the predicted NPP carbon flux of grazed lands by 59 grams C per square meter annually compared to unmanaged grasslands. Low intensity grazing activity appeared to promote higher grass regrowth until June, compared to the ungrazed grassland sites. These modeling methods were shown to be successful in capturing the differing seasonal growing cycles of rangeland forage production across the area of individual ranch properties.

P-wave tomography of crust and upper mantle under Southern California: Influence of topography of Moho discontinuity

We use 146 422 P-wave arrival times from 6 347 local earthquakes recorded by the Southern California SeismicNetwork to determine a detailed three-dimensional P-wave velocity structure at 0～35 km depth. We have takeninto account the Moho depth variations, which were obtained by seismological methods. Checkerboard tests sug-gest that our inversion results are reliable. Our models provide new information on regional geological structuresof Southern California. At shallow depths P-wave velocity structure correlates with surface geological features andexpresses well variations of surface topography of the mountains and basins. The velocity structure at each layer ischaracterized by block structures bounded by large faults. Ventura Basin, Los Angeles Basin, Mojave Desert, Pen-insular Ranges, San Joaquin Valley, Sierra Nevada, and Salton Trough show respectively all-round block. SanAndreas Fault becomes an obvious boundary of the region. To its southwest, the velocity is higher, and there arestrong heterogeneity and deeper seismicity; but to its northeast, the velocity is lower and shows less variation thanto the southwest, the seismicity is shallower. To investigate the effect of the Moho geometry we conducted inver-sions for two cases: one for flat Moho geometry, another for a Moho with lateral depth variations. We found thatthe topography of the Moho greatly affects the velocity structure of the middle and lower crust. When the Mohotopography is considered, a more reasonable tomographic result can be obtained and the resulting 3-D velocitymodel fits the data better.

Vegetation Regrowth Following Wildfires in the Santa Cruz Mountains of Northern California Monitored Using Landsat Satellite Image Analysis

The Santa Cruz Mountain range in northern California is a coastal landscape with a history of extensive forest logging and frequent large wildfires that have recently destroyed numerous residential structures at the wildland interface. Results from Landsat satellite image time-series analysis since 1984 of the study area within the Los Gatos Creek and Corralitos Creek watersheds showed that none of the severe drought periods since the 1980s have notably inhibited rapid tree and shrub regrowth rates on steep hill slopes burned recently by the 1985 Lexington Fire and the 2008 Summit Fire. In high burn severity areas of both fires, post-fire vegetation types showed a marked increase in shrub cover, mainly at the expense of evergreen tree cover. Most of these low (<3 m), dense stands of evergreen woody species have regenerated in as little as five years from bare charred ground. A combination of Landsat and Laser Altimeter (GLAS) satellite sensor data revealed that exposed south-facing slopes are presently supporting 200 to 240 Mg·ha-1 of standing woody biomass on the burned areas. This study is the first of its kind to utilize a full 30-year record of Landsat vegetation index data to monitor tree and shrub regrowth after stand-replacing wildfires in California.

Predictors of colorectal cancer testing using the California Health Inventory Survey

AIM:To identify key variables associated with colon cancer testing using the 2009 California Health Inventory Survey(CHIS).METHODS:The CHIS has been conducted biennially since 2001 using a two-stage,geographically stratified random-digit-dial sample design to produce a representative sample of the entire State.For this study we used survey data from 2001-2009 inclusive.We restricted our analysis to White,Black,and Hispanic/Latinos aged 50-80 years.Weighted data was used to calculate the proportion of participants who underwent some form of colon cancer testing(colonoscopy,flexible sigmoidoscopy or fecal occult blood testing) within the previous 5 years stratified by race/ethnicity.For inferential analysis,boot-strapping with replacement was performed on the weighted sample to attain variance estimates at the 95%CI.For mean differences among categories we used t-tests and for comparisons of categorical data we used Pearson's χ 2.Binary logistic regression was used to identify independent variables associated with undergoing some form of testing.Trend analysis was performed to determine rates of testing over the study period stratified by race.RESULTS:The CHIS database for 2009 had 30 857 unique respondents corresponding to a weighted sample size of 10.6 million Californians.Overall,63.0%(63.0-63.1) underwent a colon cancer test within the previous 5 years;with 70.5%(70.5%-70.6%) of this subset having undergone colonoscopy.That is 44.5%(44.4%-44.5%) of all individuals 50-80 underwent colonoscopy.By multivariable regression,those tested were more likely to be male(OR = 1.06;95%CI:1.06-1.06),Black(OR = 1.30;95%CI:1.30-1.31),have a family member with colon cancer(OR = 1.71;95%CI:1.70-1.72),and have health insurance(OR = 2.71;95%CI:2.70-2.72).Progressive levels above the poverty line were also associated with receiving a test(100%-199%:1.21;1.20-1.21),(200%-299%:1.41;1.40-1.42),(> 300:1.69;1.68-1.70).The strongest variable was physician recommendation(OR = 3.90;95%CI:3.88-3.91).For the Hispanic/Latino group,additional variables associated with testing were success of physician-patient communication(OR = 2.44;95%CI:2.40-2.48) and naturalized citizenship status(OR = 1.91;95%CI:1.89-1.93).Trend analysis demonstrated increased colon cancer testing for all racial/ethnic subgroups from 2001-2009 although the rate remained considerably lower for the Hispanic/Latino subgroup.CONCLUSION:Using CHIS we identified California citizens most likely to undergo colon cancer testing.The strongest variable associated with testing for all groups was physician recommendation.

Recent Developments of Earthquake Early Warning in California,USA

In this paper we outline the science,engineering,and societal considerations of the prototype Earthquake Early Warning System( EEWS) in California and detail the development and testing of methodologies in the last 10 years in America. Also,we give a brief introduction of Earthquake Early Warning( EEW) in China,and based on the summary of EEW in California we make an analysis of the perspectives,misconceptions,and challenges that China may have.

Major Ion Geochemistry of Groundwaters from Southern Nevada and Eastern California, USA

The dissolved ionic constituents of groundwaters are, in part, a record of the minerals and rocks in aquifers through which the water has flowed. The chemical composition and association of these major ions in groundwaters have been used to trace groundwater flow paths and sources. In general, the chemical composition of water in carbonate\|rock aquifers is dominated by calcium, magnesium, and bicarbonate, whereas sodium, chloride, and sulfate can be dominant ions in the water that comes from volcanic aquifers or clay minerals. Since the \{1990’s\}, we have dealt with the geochemistry of groundwaters from more than 100 springs and wells in southern Nevada and eastern California, USA for major solutes and trace elements. This paper compiles the hydrochemical data of major ions of these groundwaters. Based on major ion geochemistry, groundwaters from southern Nevada and eastern California can be classified as carbonate aquifer water, volcanic aquifer water, and mixing water (either mixing of carbonate and volcanic aquifer waters or mixing with local recharges). Piper and Stiff diagrams of major ions have graphically shown the general chemical characteristics, classifications, and mixing relationships of groundwaters from southern Nevada and eastern California.

Decadal Forecasts of Large Earthquakes along the Northern San Andreas Fault System, California: Increased Activity on Regional Creeping Faults Prior to Major and Great Events

The three largest earthquakes in northern California since 1849 were preceded by increased decadal activity for moderate-size shocks along surrounding nearby faults. Increased seismicity, double-difference precise locations of earthquakes since 1968, geodetic data and fault offsets for the 1906 great shock are used to re-examine the timing and locations of possible future large earthquakes. The physical mechanisms of regional faults like the Calaveras, Hayward and Sargent, which exhibit creep, differ from those of the northern San Andreas, which is currently locked and is not creeping. Much decadal forerunning activity occurred on creeping faults. Moderate-size earthquakes along those faults became more frequent as stresses in the region increased in the latter part of the cycle of stress restoration for major and great earthquakes along the San Andreas. They may be useful for decadal forecasts. Yearly to decadal forecasts, however, are based on only a few major to great events. Activity along closer faults like that in the two years prior to the 1989 Loma Prieta shock needs to be examined for possible yearly forerunning changes to large plate boundary earthquakes. Geodetic observations are needed to focus on identifying creeping faults close to the San Andreas. The distribution of moderate-size earthquakes increased significantly since 1990 along the Hayward fault but not adjacent to the San Andreas fault to the south of San Francisco compared to what took place in the decades prior to the three major historic earthquakes in the region. It is now clear from a re-examination of the 1989 mainshock that the increased level of moderate-size shocks in the one to two preceding decades occurred on nearby East Bay faults. Double-difference locations of small earthquakes provide structural information about faults in the region, especially their depths. The northern San Andreas fault is divided into several strongly coupled segments based on differences in seismicity.

Unsheltered: Navigating California’s Homelessness Crisis

This paper presents a comprehensive exploration of the complex phenomenon of homelessness in California,with a specific focus on the state’s three largest cities-Los Angeles,San Francisco,and San Diego.Against the backdrop of a high cost of living and a housing market strained by insufficient affordable options,the multifaceted nature of social diversity further complicates the landscape,leading to a widespread presence of homelessness that spans both major urban centers and rural regions.Through an in-depth examination of the distinct challenges confronting each city,ranging from housing shortages to intricate social dynamics,this study seeks to illuminate the underlying factors driving homelessness and identify potential avenues for intervention.Moreover,the paper delves into the unique vulnerabilities experienced by certain demographics within the homeless population,including veterans,families with children,and LGBTQ+individuals,highlighting the critical need for targeted solutions tailored to their specific needs.By synthesizing existing research and incorporating firsthand accounts,this research endeavor aims to contribute to a deeper understanding of homelessness in California and inform the development of comprehensive strategies aimed at fostering inclusive,sustainable communities statewide.

Case Study on Synchronous Construction Technology for Secondary Lining of Large-diameter Single track Shiel Shield-bored ored Tunnel

The synchronous construction of the secondary lining during the boring of large-diameter shield faces challenges such as the design of the lining jumbo,the high requirements on the performance for the lining jumbo,the organization of the construction activities in the small and confined area,the horizontal transportation for shield boring and high safety management requirements.A super-long invert lining construction jumbo,as well as the matching California switch,is developed,which provides solution for the confliction between the invert lining construction and the horizontal transportation.The procedure and method for the synchronous operation of the shield boring and the secondary lining are developed by referring to the synchronous construction of the secondary lining during the boring of the TBMs in hard rocks.Due to the adoption of the synchronous operation of the shield boring and the secondary lining,the construction period is shortened and the construction cost is reduced.The paper can provide reference for the synchronous construction of the secondary lining in similar projects in the future.

First Successful Nesting of Black Oystercatchers among Endangered California Least Terns along the West Coast of North America

A pair of Black Oystercatchers(Haematopus bachmani)established a nest in June 2022 at“Tern Town”,an island located in Hayward,California along the eastern side of the San Francisco Bay.This is the first documented occurrence of oystercatchers successfully nesting and fledgling young in association with California Least Terns.The island provides nesting habitat for three special status species.Since 2015,and for a total of six breeding seasons,the endangered California Least Tern(Sternula antillarum browni),the threatened Western Snowy Plover(Charadrius alexandrinus nivosus)and species-of-special-concern Black Skimmer(Rynchops niger),have nested successfully,in association with American Avocet(Recurvirostra americana)and Black-necked Stilt(Himantopus mexicanus).We collected shells near the oystercatcher nest to assess their diet.Diet data showed the oystercatchers foraged on,in decreasing order of abundance,Japanese Little-necked Clams(Ruditapes philippinarum),Ribbed Mussels(Geukensia demissa),Bent-nose Clams(Macoma nasuta),Limpets(Patellogastropoda sp.)and Bay Mussels(Mytilus edulis).This new report on breeding Black Oystercatchers indicates that managing habitat for California Least Tern,Western Snowy Plover,and Black Skimmer can also benefit Black Oystercatcher.This site-specific information on breeding Black Oystercatchers supports recovery plan tasks that are consistent with managing habitat for California Least Tern,Western Snowy Plover and Black Skimmer.

A/California/7/2009与A/California/4/2009病毒感染力比较

目的甲型H1N1流感病毒A/California/7/2009与A/California/4/2009病毒序列比较同源性在99%以上,本实验旨在比较两株病毒感染BALB/c小鼠研究感染力强弱。方法分别将A/California/7/2009（CA7）与A/California/4/2009（CA4）两株病毒分别连续10倍稀释后,对4~6周龄雌性BALB/c小鼠经乙醚麻醉后进行滴鼻攻毒,每个稀释度接种10只实验小鼠,测定CA7 MLD50为101.24/0.05 mL,检测小鼠感染、致病的多项指标,观察期为14 d。结果相同TCID50的CA7和CA4病毒感染小鼠,CA4感染小鼠后14 d内死亡率为20%,而CA7感染小鼠后8 d内死亡率为100%。CA7 106TCID50感染的小鼠病理表现为重度弥漫性间质性肺炎,CA4 106TCID50感染的小鼠病理表现为中度-重度间质性肺炎。结论在相同条件下,CA7感染力明显强于CA4。

California Bearing Ratio for Cohesive Soils from Quasi Static Cone Tests

The California bearing ratio (CBR) test is the most widely spread method of determining the bearing strength of the pavement material and is fundamental to pavement design practice in most countries. This test is expensive, laborious and time consuming, and to overcome this, Quasi static cone penetrometer machine was fabricated and used to measure the consistency limits (liquid limit-LL, Plastic limit-PL and Plasticity index-PI), which were used to develop an empirical equation to determine CBR. Soil samples were collected and unsoaked CBR, PL, LL and PI were determined according to BS 1377 part 9 and BS 1377-2;1990. Quasi static penetration forces at 20 mm depth of penetration were also determined at consistency limits. It was found that the force of 1020 gf and 60 gf was achieved at a depth of 20 mm at PI and LL respectively. The correlation and regression analysis between consistency limits, and the experimental CBR obtained showed coefficient of determination, R2 = 0.907 between CBR and all the parameters using multiple linear regression analysis (MLRA). The regression equation developed was used together with the relationship developed between the Quasi static Penetration force at consistency limits and the tested consistency limits to come up with the General Empirical Equation. Verification of the formula showed that the correlation can be used accurately to determine the un soaked CBR.

Baja California边缘PC14岩芯海水表层温度及生产力变化的百年尺度记录

加利福尼亚流是北太平洋环流的重要组成部分,它的变化对全球气候及碳循环有重要影响。对位于东北太平洋低纬区Baja California外海的PC14柱状样进行了有机地球化学分析,重建了过去14ka来这一地区百年尺度的海水表面温度及生产力变化,发现其存在明显的B/A(Bling-Aller)和YD(Younger Drays)事件,但B/A和YD事件温度变化幅度小于中纬度地区。与中纬度加利福尼亚流系早中全新世温度降低不同,PC14全新世温度无明显变化趋势。这些结果表明了东太平洋低纬地区对高纬地区的气候响应以及沿岸上升流和ENSO现象对加利福尼亚流系中纬和低纬地区的影响不同。从冰消期到全新世,PC14生产力呈现阶段上升趋势,指示了由E1 Ni?o气候向La Ni?a气候的转化以及沿岸上升流加强的总体趋势。在全新世中后期(6.5—3.8ka)生产力的降低,则可能是受ENSO加强的影响。在B/A暖期,PC14生产力增加不多,但氧最小层强度增加,这表明生产力变化不是东太平洋边缘海的氧最小层强化的控制因素。

A/California/07／2009亚型猪流感冷适应减毒疫苗株的拯救及免疫效果评价

应用反向遗传学技术,选择冷适应、温度敏感、减毒的A/Ann Arbor/6/60 ca(H2N2)型流感病毒的6个内部基因为骨架,与A/California/07/2009株流感病毒2个抗原基因HA、NA分别克隆到polⅠ-polⅡ转录表达载体pAD3000中,构建8个转录表达载体重组质粒,共转染Vero细胞,获得重配A/California/07/2009ca株流感病毒.重配病毒的TCID50为7.5,病毒传4代后其血凝素(HA)滴度稳定在1∶256,半数感染剂量EID50为8,鸡胚传20代,经RT-PCR鉴定未发现重组病毒基因突变,电镜观察重配病毒符合流感病毒的主要特征;蔗糖纯化的病毒经肌肉注射(灭活)及滴鼻(减毒活病毒)两种途径免疫BALB/c小鼠,结果显示:滴鼻免疫和肌肉注射都可以产生较高效价的血凝抑制(HI)抗体,肌肉注射组产生的HI抗体略高(P=0.044),但肌肉注射组检测不到高效价IgA抗体;滴鼻免疫组鼻冲洗液中可以检测到高效价的IgA抗体,同型病毒感染后,IL-1β、TNFα、IFN-α等前炎因子分泌较早,且高于肌肉注射组(P<0.05),可见,喷鼻减毒疫苗比灭活全病毒疫苗能更好地激发黏膜免疫反应.通过对小鼠各个器官病毒载量的检测发现,4天后鼻腔、气管、脑、肺、脾脏没有病毒存在,证明减毒活疫苗株在小鼠上是安全的.以上数据可以初步断定,重组病毒有作疫苗候选株的可能,而且喷鼻疫苗具有降低免疫剂量、同时激活体内体液免疫和细胞免疫的功能.