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1.
Esau , Katherine . (U. California, Santa Barbara.) Ultrastructure of differentiated cells in higher plants. Amer. Jour. Bot. 50(5): 495–506. Illus. 1903.—This paper reviews the rather meager information on differences between meristematic and fully differentiated cells of higher plants at the ultrastructural level. It includes personal observations on differentiated cells in Cucurbita maxima and Vitis vinifera, particularly those of the phloem tissue. The structures considered and illustrated by means of electron micrographs are vacuoles, the nucleus, mitochondria, the endoplasmic reticulum, dictyosomes, plasmodesmata, and, briefly, plastids.  相似文献   

2.
The following remarks are excerpts from an address by T. Eric Reynolds, M.D., President of the California Medical Association, at a meeting of the Woman''s Auxiliary to the California Medical Association, Santa Barbara, September, 1959  相似文献   

3.
The following remarks are excerpts from an address by T. Eric Reynolds, M.D., President of the California Medical Association, at a meeting of the Woman's Auxiliary to the California Medical Association, Santa Barbara, September, 1959.  相似文献   

4.
Abstract. The California grassland is dominated by alien plant species. It is generally assumed that the invasion of aliens began with the initial introduction of livestock by Spanish missionaries in 1769. In this paper we present pollen evidence which indicates that Erodium cicutarium, a Mediterranean annual, was well established in the Santa Barbara region several years before the founding of the first California mission at San Diego in 1769. Historical evidence shows that it took the Spanish nearly a decade to develop a livestock base in California. Disturbance by livestock was therefore not a necessary prerequisite for invasion by alien plants. Historical and macrofossil evidence indicates that E. cicutarium invaded California from Baja California.  相似文献   

5.
Selection pressure from health risk is hypothesized to have shaped adaptations motivating individuals to attempt to become valued by other individuals by generously and recurrently providing beneficial goods and/or services to them because this strategy encouraged beneficiaries to provide costly health care to their benefactors when the latter were sick or injured. Additionally, adaptations are hypothesized to have co-evolved that motivate individuals to attend to and value those who recurrently provide them with important benefits so they are willing in turn to provide costly care when a valued person is disabled or in dire need. Individuals in egalitarian foraging bands can provide a number of valuable benefits, such as defense, diplomacy, food, healing, information, technical skill, or trading savvy. We therefore expect that humans have evolved psychological mechanisms motivating the pursuit and cultivation of a difficult-to-replace social role based on the provisioning of a benefit that confers a fitness advantage on its recipients. We call this phenomenon social niche specialization. One such niche that has been well-documented is meat-sharing. Here we present cross-cultural evidence that individuals cultivate two other niches, information and tool production, that serve (among other things) to buffer health risk. Michelle Scalise Sugiyama studied at the Center for Evolutionary Psychology at the University of California, Santa Barbara, where she received her Ph.D. in literature in 1997. She is currently an affiliate of the English Department and the Institute for Cognitive and Decision Sciences at the University of Oregon, Eugene, and also directs the Cognitive Cultural Studies branch of the Human Universals Project at the Center for Evolutionary Psychology. Her work attempts to understand narrative and other art behaviors in terms of the cognitive architecture that underlies them and the ancestral conditions under which they emerged; published results can be found in Human Nature, Evolution and Human Behavior, Philosophy and Literature, and Mosaic. Lawrence Sugiyama holds a joint appointment in the Anthropology Department and the Institute for Cognitive and Decision Sciences at the University of Oregon, Eugene. He did his graduate work at the Center for Evolutionary Psychology at the University of California, Santa Barbara, where he cofounded the Human Universals Project and the Ecuadorian Oriente Research Station, which he now directs. His research among the Shiwiar, Yora, and Yanomamo examines health risk, cooperation, reciprocity, subsistence, and life history patterns among contemporary forager-horticulturalists, with the ultimate goal of furthering our understanding of pat selection pressures and the psychology evolved to surmount them. Published results can be found in Proceedings of the National Academy of Science, American Journal of Physical Anthropology, and Adaptation and Human Behavior: An Anthropological Perspective.  相似文献   

6.
While this special issue of TIG was in preparation, the news came that Barbara McClintock bad died at the age of 90 (2 September 1992). Her pioneering work on transposable elements, which was fundamental to the development of research on DNA rearrangements, makes it appropriate that we pay tribute to her in this issue. Regine Kahmann, now a Professor at the University of Munich, worked in the Cold Spring Harbor Laboratory from 1974 until 1980, and came to know Barbara McClintock well. In this ‘personal view’, she remembers Barbara McClintock as an inspiration to an aspiring young scientist.  相似文献   

7.
The barn owl (Tyto alba) is a non-migratory species widely distributed across much of North America in areas with extensive old-field and grassland habitat and without extensive winter snow cover. We investigated the genetic diversity and phylogeographic patterns of barn owl populations in western North America, ranging from British Columbia (BC) to southern California, and one eastern population from Pennsylvania. We also determined the genetic distinctiveness of a population off the coast of southern California, Santa Barbara Island, as management plans to control the local owl population are being considered to decrease predation rate on the now threatened Scripps’s Murrelet (Synthliboramphus scrippsi). Using 8 polymorphic microsatellite markers (N = 126) and ND2 mitochondrial sequences (N = 37), we found little to no genetic structure among all sampled regions, with the exception of Santa Barbara Island. The BC mainland population, despite its northwestern geographically peripheral location and ongoing habitat degradation, is not genetically depauperate. However, individuals from Vancouver Island, likewise a peripheral population in BC, exhibited the lowest genetic diversity of all sampled locations. The low global FST value (0.028) estimated from our study suggests that old-field agricultural habitats are well connected in North America. Since the BC population has declined by about 50 % within the last three decades, it is vital to focus on preserving the remaining barn owl habitats in BC to allow successful establishment from neighbouring populations. Additionally, our microsatellite data revealed that the population on Santa Barbara Island showed genetic divergence from its continental counterpart. Mitochondrial data, however, demonstrated that this island population is not a monophyletic lineage containing unique haplotypes, and hence cannot be designated as an Evolutionarily Significant Unit.  相似文献   

8.
Tillmann  U. 《Journal of phycology》2003,39(S1):56-56
Invasive algal species have the potential to change the structure and ecology of native algal communities. One well-known invader, the large Japanese kelp Undaria pinnatifida , has recently become established at several locations along the central and southern California coast (Monterey, Santa Barbara, Catalina, and others). Previous to its introduction in the northeastern Pacific, Undaria has become established along the coastlines of several countries, including Australia, New Zealand, Argentina, England, and France. However, the seasonal population dynamics, rate of spread, and impact on local communities at each invasion site varies. Undaria in the Santa Barbara, CA harbor exhibits two distinct recruitment pulses per year (fall, late winter), with nonoverlapping generations of adult individuals. Individuals can grow rapidly and become reproductive a month after appearing as recruits (2–3 cm long), indicating a potential for rapid spread. However, Undaria may be effectively controlled by grazing via natural recruitment of the kelp crab Pugettia producta. However, Undaria invasions in other California invasions have not been controlled by herbivory, and Undaria populations in these areas have the potential to compete with a wide diversity of native California kelp species for habitat space and light.  相似文献   

9.
We present the unusual case of a 17-year-old female with insulin-resistant diabetes, acanthosis nigricans, hirsutism, amenorrhea, dental dysplasia and lipopexia on the extremities. She had been diagnosed as having border line diabetes with hyperinsulinemia at age 12 when she was not obese and diabetes mellitus at age 13. On admission, she was obese and had lipopexia only on the extremities. The presence of hyperinsulinemia and poor response to exogenous insulin suggested severe insulin resistance. Insulin binding to transformed B-lymphoblasts derived from her was extremely low compared to the normal control, showing decreased receptor affinity. Her parents and sister exhibited hypersecretion of insulin in response to a 75 g oral glucose tolerance test. Her mother was diabetic, and her father and sister had border line diabetes, whereas her brother had a normal response. These findings support strongly the diagnosis of a type A syndrome with severe insulin resistance associated with lipopexia on the extremities. A genetic defect in the insulin receptor gene may be responsible.  相似文献   

10.
Objective To examine the financial and organizational characteristics, demand for services, and satisfaction outcomes of a growing telemedicine program serving both urban or suburban and rural populations. Design Retrospective review of 1,000 consecutive telemedicine consultations in the University of California (UC) Davis Telemedicine Program. Setting Telemedicine videoconferencing units, used to integrate care in the UC Davis Health System among the UC Davis Medical Center and several urban or suburban primary care clinics, rural hospitals, and clinic affiliates. Subjects A total of 657 consecutive patients who consented to a telemedicine consultation. Main outcome measures Demographic information about the patient population, the rural and urban or suburban clinics, the types of specialty consultations, and telemedicine equipment used in the UC Davis Health System. Patient and physician satisfaction were measured on a 5-point Likert scale. Results Patients and primary care physicians reported high levels of satisfaction. Rural clinics requested more and a greater variety of specialist consultations than urban or suburban clinics. Conclusion Although referring physicians and patients indicate a high level of satisfaction with telemedicine services and insurers are negotiating reimbursement policies, additional research must investigate the reasons why some payers, patients, and providers resist participation in these services.  相似文献   

11.
Invasive algal species have the potential to change the structure and ecology of native algal communities. One well‐known invader, the large Japanese kelp Undaria pinnatifida, has recently become established at several locations along the central and southern California coast (Monterey, Santa Barbara, Catalina, and others). Previous to its introduction in the northeastern Pacific, Undaria has become established along the coastlines of several countries, including Australia, New Zealand, Argentina, England, and France. However, the seasonal population dynamics, rate of spread, and impact on local communities at each invasion site varies. Undaria in the Santa Barbara, CA harbor exhibits two distinct recruitment pulses per year (fall, late winter), with nonoverlapping generations of adult individuals. Individuals can grow rapidly and become reproductive a month after appearing as recruits (2–3 cm long), indicating a potential for rapid spread. However, Undaria may be effectively controlled by grazing via natural recruitment of the kelp crab Pugettia producta. However, Undaria invasions in other California invasions have not been controlled by herbivory, and Undaria populations in these areas have the potential to compete with a wide diversity of native California kelp species for habitat space and light.  相似文献   

12.
A primary goal of conservation genetics is the discovery, delimitation and protection of phylogenetic lineages within sensitive or endangered taxa. Given the importance of lineage protection, a combination of phylogeography, historical geology and molecular clock analyses can provide an important historical context for overall species conservation. We present the results of a range-wide survey of genetic variation in the California tiger salamander, Ambystoma californiense, as well as a summary of the past several million years of inundation and isolation of the Great Central Valley and surrounding uplands that constitute its limited range. A combination of population genetic and phylogenetic analyses of mitochondrial DNA variation among 696 samples from 84 populations revealed six well-supported genetic units that are geographically discrete and characterized by nonoverlapping haplotype distributions. Populations from Santa Barbara and Sonoma Counties are particularly well differentiated and geographically isolated from all others. The remaining units in the Southern San Joaquin Valley, Central Coast Range, Central Valley and Bay Area are separated by geological features, ecological zone boundaries, or both. The geological history of the California landscape is consistent with molecular clock evidence suggesting that the Santa Barbara unit has been isolated for at least 0.74-0.92 Myr, and the Sonoma clade is equally ancient. Our work places patterns of genetic differentiation into both temporal- and landscape-level contexts, providing important insights into the conservation genetics of the California tiger salamander.  相似文献   

13.
Boat-based photoidentification surveys of bottlenose dolphins (Tursiops truncatus) were conducted from 1982 to 1989 in three discrete coastal study areas within the Southern California Bight: (1) Santa Barbara, California; (2) Orange County, California; (3) Ensenada, Baja California, Mexico. A total of 207 recognizable dolphins were identified in these three “secondary” study areas. These individuals were compared to 404 dolphins identified from 1981 to 1989 in our “primary” study area, San Diego, California, to examine the coastal movement patterns of bottlenose dolphins within the Southern California Bight. A high proportion of dolphins photographed in Santa Barbara (88%), Orange County (92%), and Ensenada (88%) were also photographed in San Diego. Fifty-eight percent (n= 120) of these 207 dolphins exhibited back-and-forth movements between study areas, with no evidence of site fidelity to any particular region. Minimum range estimates were 50 and 470 km. Minimum travel-speed estimates were 11-47 km/d, and all dolphin schools sighted during the study were within 1 km of the shore. These data suggest that bottlenose dolphins within the Southern California Bight are highly mobile within a relatively narrow coastal zone. Home-range dimensions and movement patterns for many vettebrate species are influenced, in part, by variation in food resources. The unique range characteristics documented during this study may reflect the highly dynamic nature of this coastal ecosystem and the associated patchy distribution of food resources available to these bottlenose dolphins.  相似文献   

14.
Macroalgae are important primary producers in many subtidal habitats, yet little information exists on the temporal and spatial dynamics of net primary production (NPP) by entire subtidal assemblages. This knowledge gap reflects the logistical challenges in measuring NPP of diverse macroalgal assemblages in shallow marine habitats. Here, we couple a simple primary production model with nondestructive estimates of taxon‐specific biomass on subtidal reefs off Santa Barbara, California to produce a 4‐year time series of net primary production by intact assemblages of understory macroalgae in giant kelp forests off Santa Barbara, California, USA. Daily bottom irradiance varied significantly throughout the year, and algal assemblages were on average exposed to saturating irradiance for only 1.3–4.5 h per day, depending on the time of year. Despite these variable light‐limiting conditions, biomass rather than irradiance explained the vast majority of variation observed in daily NPP at all times of the year. Measurements of peak biomass in spring and summer proved to be good predictors of NPP for the entire year, explaining as much as 76% of the observed variation. In contrast, bottom irradiance was a poor predictor of NPP, explaining <10% of the variation in NPP when analyzed seasonally and ~2% when evaluated annually. Our finding that annual NPP by macroalgal assemblages can be predicted from a single, nondestructive measurement of biomass should prove useful for developing time series data that are necessary to evaluate natural and anthropogenic changes in NPP by one of the world's most productive ecosystems.  相似文献   

15.
California sea lions (Zalophus californianus) in otherwise good nutritional condition have been consistently affected by the marine biotoxin domoic acid since the late 1990s. In this study we evaluated the temporal and spatial stranding patterns of suspected and confirmed cases of domoic acid intoxicated sea lions from 1998 to 2006, using records of strandings along the California coast obtained from members of the California Marine Mammal Stranding Network. The majority of domoic acid cases were adult females (47%–82% of the total annual domoic acid cases), a contrast to strandings that were not related to domoic acid, which were generally dominated by juveniles and pups. Exposure to this biotoxin led to a 6.67‐fold increase in adult female strandings in 2000, and a 5.44‐fold increase in adult female deaths in 2006, relative to strandings and deaths of adult female not affected by domoic acid. Domoic acid cases have occurred annually since 1998 (except for 1999) between April and August, with clusters centered primarily at Pismo Beach (San Luis Obispo County), as well as at other beaches in San Luis Obispo, Monterey, Santa Cruz, Santa Barbara, Orange, and San Diego counties. The larger ecological and population level implications of increased domoic acid strandings and deaths, particularly among adult female sea lions, warrant further attention and need to be investigated.  相似文献   

16.
Summary Coastal sage scrub is a community found extensively throughout cismontane California south of San Francisco, but has been surprisingly little studied. In the study area, which extends from Santa Barbara to the San Gorgonio Pass, two major floristic groupings can be found. In the basin bounded coastwards by a line drawn along the axis of the Santa Ana Mountains a large number of native and introduced annual herbs and a few shrubs (e.g.Encelia farinosa), rare or absent in the remainder of the study area, characterize one floristic group. In the coastal region the variety of shrub species increases, and the herbs are predominantly native and more restricted in number. Eleven groups defined by physiognomy, structure and species dominance, and arbitrarily called associations, are recognized. These associations can be grouped into four physiognomic-structural types which transgress the boundaries of the floristic groups. The results of this study and the limited previous literature suggest that Californian coastal sage scrub could be divided, mainly on floristic criteria, into Venturan, San Diegan and Riversidian sage.Plant nomenclature follows Munz & Keek (1968).We gratefully acknowledge the financial help provided by the Department of Earth Sciences, University of California, Riverside, and the aid in plant identification provided by Mr. Oscar Clarke, Museum Scientist, Department of Biology, University of California, Riverside.  相似文献   

17.
Three geographically isolated populations of the giant kelp, Macrocystis pyrifera (L.) C. Ag., were examined for responses to nitrate availability in batch culture experiments using juvenile sporophytes reared from spores in the laboratory. Although maximum rates of nitrate-saturated growth were similar among groups, there were significant quantitative differences in the response to nitrate limitation that can be related to natural patterns of nutrient availability at these sites. Plants from Santa Catalina Island (most oligotrophic) achieved maximum growth rates at ambient nitrate concentrations that were lower than those for plants from Monterey Bay, California (most eutrophic), or Refugio State Beach (near Santa Barbara, California). Tissue nitrogen and amino acid concentrations were highest in plants cultured from Santa Catalina Island populations at all external nitrate concentrations, suggesting that differences in nitrate requirements for growth may reflect the efficiency of nitrate uptake and assimilation at subsaturating nitrate concentrations. Given the different physical environments from which these plants came, the data suggest that geographically isolated populations of M. pyrifera have undergone genetic divergence that can be explained by ecotypic adaptation to unique habitat conditions at these sites.  相似文献   

18.
Abstract The Pacific islands off southern California, U.S.A. and Baja California, Mexico hold potential for the conservation and restoration of California Mediterranean coastal ecosystems. However, the presence of exotic herbivores and invasive plants pose threats to these systems. Here, we use introduced herbivore removal as a large‐scale experimental manipulation to examine the importance of top‐down and bottom‐up processes to a large‐scale restoration effort. Using a paired approach on the Todos Santos Islands, Mexico we removed herbivores from one island, while they temporarily remained on an adjacent and similar island. We augmented this experiment with smaller scale herbivore exclosures on the control island. At both scales we failed to detect an herbivore effect on the plant community; rather plant community dynamics appeared to be dominated by El Niño related precipitation and exotic annuals. A parallel experiment on the San Benito Islands, Mexico revealed a different dynamic: Top‐down effects on the plant community by exotic herbivores were evident. Differences in the response from the plant communities to both exotic herbivore presence and removal between these two island groups, along with Santa Barbara Island, U.S.A., where restoration has been on‐going, raise important questions in ecosystem restoration. The history of anthropogenic disturbance, exotic plant abundance, and aridity play roles in postherbivore removal recovery. Although island conservation practitioners have honed the ability to remove exotic mammals from islands, development of invasive plant removal techniques is needed to fully capitalize on the conservation potential of California island ecosystems.  相似文献   

19.
The complexity of human societies of the past few thousand years rivals that of social insect societies. We hypothesize that two sets of social “instincts” underpin and constrain the evolution of complex societies. One set is ancient and shared with other social primate species, and one is derived and unique to our lineage. The latter evolved by the late Pleistocene, and led to the evolution of institutions of intermediate complexity in acephalous societies. The institutions of complex societies often conflict with our social instincts. The complex societies of the past few thousand years can function only because cultural evolution has created effective “work-arounds” to manage such instincts. We describe a series of work-arounds and use the data on the relative effectiveness of WWII armies to test the work-around hypothesis. Richerson received his Ph.D. degree in zoology from UC Davis in 1969. He is currently a professor in the Department of Environmental Science and Policy. In addition to his work in cultural evolution, he has worked on the limnology of Lake Tahoe and Clear Lake in California, and on Lake Titicaca in Peru and Bolivia. Boyd received his Ph.D. degree in ecology from UC Davis in 1975, though his thesis work was a resource economics problem. He is currently a professor of anthropology at UCLA. His research interests besides cultural evolution are game theory and a small bit of primatology from time to time.  相似文献   

20.
The issues of dislocated identity are epitomised in Mary's story. Brought from Papua New Guinea to Australia at a very young age as a ‘gift’, she grew up in a series of foster homes in Adelaide, South Australia. Now, as a teenager, Mary constitutes her identity through her body, emphasising her distinctive physical features, through idealised memories and through representations—photographs, cultural icons and people who ‘look like me’. The self she creates in this way sits uneasily along side another self; the Western adolescent self in trouble with the law, the self who struggles to be ‘one of the boys’ on the streets, one who ‘runs amuck’. This paper explores the process of ‘self-making’, the ‘serious play’ that Mary has employed to constitute her identity through her juggling of and reappropriation of cultural symbols. As a participant in a wider ethnographic study into Australian youth and representation, Mary portrayed the complexities of her growing up between worlds, embedded in neither and desperate to belong to her past.  相似文献   

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