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Author: Anderson, J.A.

Description: A model of a neural system where a group of neurons projects to another group of neurons is discussed. We assume that a trace is the simultaneous pattern of individual activities shown by a group of neurons. We assume synaptic interactions add linearly and that synaptic weights (quantitative measure of degree of coupling between two cells) can be coded in a simple but optimal way where changes in synaptic weight are proportional to the product of pre-and postsynaptic activity at a given time. Then it is shown that this simple system is capable of "memory" in the sense that it can (1) recognize a previously presented trace and (2) if two traces have been associated in the past (that is, if trace 1 was impressed on the first group of neurons and trace 2 was impressed on the second group of neurons and synaptic weights coupling the two groups changed according to the above rule) presentation of 1 to the first group of neurons gives rise to 2; plus a calculable amount of noise at the second set of neurons. This kind of memory is called an "interactive memory" since distinct stored traces interact in storage. It is shown that this model can effectively perform many functions. Quantitative expressions are derived for the average signal to noise ratio for recognition and one type of association. The selectivity of the system is discussed. References to physiological data are made where appropriate. A sketch of a model of mammalian cerebral cortex which generates an interactive memory is presented and briefly discussed. We identify a trace with the activity of groups of cortical pyramidal cells. Then it is argued that certain plausible assumptions about the properties of the synapses coupling groups of pyramidal cells lead to the generation of an interactive memory.

Title: A simple neural network generating an interactive memory

Subject headings: Neural network; Neurons; Synapses; Pyramidal cells; Interactive memory

Year: 1972

Publication: Mathematical Biosciences

Volume: 14

Issue: 3-4

Pages: 197-220

Full text: http://linkinghub.elsevier.com/retrieve/pii/0025556472900752

Cited by: https://scholar.google.com/scholar?cites=16016050827885146868&as_sdt=1000005&sciodt=0,16&hl=en

Format: Journal Article

ISSN: 0025-5564

ISBN:
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Author: Anderson, J.L.; Albergotti, L.; Ellebracht, B.; Huey, R.B.; Phillips, P.C.

Description: BACKGROUND: A central premise of physiological ecology is that an animal's preferred body temperature should correspond closely with the temperature maximizing performance and Darwinian fitness. Testing this co-adaptational hypothesis has been problematic for several reasons. First, reproductive fitness is the appropriate measure, but is difficult to measure in most animals. Second, no single fitness measure applies to all demographic situations, complicating interpretations. Here we test the co-adaptation hypothesis by studying an organism (Caenorhabditis elegans) in which both fitness and thermal preference can be reliably measured. RESULTS: We find that natural isolates of C. elegans display a range of mean thermal preferences and also vary in their thermal sensitivities for fitness. Hot-seeking isolates CB4854 and CB4857 prefer temperatures that favor population growth rate (r), whereas the cold-seeking isolate CB4856 prefers temperatures that favor Lifetime Reproductive Success (LRS). CONCLUSIONS: Correlations between fitness and thermal preference in natural isolates of C. elegans are driven primarily by isolate-specific differences in thermal preference. If these differences are the result of natural selection, then this suggests that the appropriate measure of fitness for use in evolutionary ecology studies might differ even within species, depending on the unique ecological and evolutionary history of each population.

Title: Does thermoregulatory behavior maximize reproductive fitness of natural isolates of Caenorhabditis elegans?

Subject headings: Acclimatization; Animals; Body Temperature Regulation; Caenorhabditis elegans--genetics, physiology; Genetic Fitness; Temperature

Year: 2011

Publication: BMC Evolutionary Biology

Volume: 11

Issue:

Pages: 157

Full text: http://bmcevolbiol.biomedcentral.com/articles/10.1186/1471-2148-11-157

Cited by: https://scholar.google.com/scholar?cites=4195369758073714613&as_sdt=1000005&sciodt=0,16&hl=en

Format: Journal Article

ISSN: 1471-2148

ISBN:
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Author: Anderson, J.L.; Albergotti, L.; Proulx, S.; Peden, C.; Huey, R.B.; Phillips, P.C.

Description: The preferred body temperature of ectotherms is typically inferred from the observed distribution of body temperatures in a laboratory thermal gradient. For very small organisms, however, that observed distribution might misrepresent true thermal preferences. Tiny ectotherms have limited thermal inertia, and so their body temperature and speed of movement will vary with their position along the gradient. In order to separate the direct effects of body temperature on movement from actual preference behaviour on a thermal gradient, we generate a null model (i.e. of non-thermoregulating individuals) of the spatial distribution of ectotherms on a thermal gradient and test the model using parameter values estimated from the movement of nematodes (Caenorhabditis elegans) at fixed temperatures and on a thermal gradient. We show that the standard lab strain N2, which is widely used in thermal gradient studies, avoids high temperature but otherwise does not exhibit a clear thermal preference, whereas the Hawaiian natural isolate CB4856 shows a clear preference for cool temperatures ( approximately 17 degrees C). These differences are not influenced substantially by changes in the starting position of worms in the gradient, the natal temperature of individuals or the presence and physiological state of bacterial food. These results demonstrate the value of an explicit null model of thermal effects and highlight problems in the standard model of C. elegans thermotaxis, showing the value of using natural isolates for tests of complex natural behaviours.

Title: Thermal preference of Caenorhabditis elegans: a null model and empirical tests

Subject headings: Acclimatization; Animals; Behavior, Animal; Body Temperature Regulation; Caenorhabditis elegans--physiology; Escherichia coli--growth & development; Models, Biological; Temperature

Year: 2007

Publication: The Journal of Experimental Biology

Volume: 210

Issue: Pt 17

Pages: 3107-3116

Full text: http://jeb.biologists.org/content/210/17/3107.long

Cited by: https://scholar.google.com/scholar?cites=11925385358292209512&as_sdt=1000005&sciodt=0,16&hl=en

Format: Journal Article

ISSN: 0022-0949

ISBN:
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Author: Anderson, J.M.

Description: This paper analyses the experiences of Anglo-Canadian and immigrant Chinese families with a chronically ill child by using the idea that the social organization and ideology of health care services generate particular illness experiences. Immigrant families find the ideology dissonant with their customs for managing illness. The disjuncture between practices often leads to non-compliance and ineffective treatment. Health professionals explain non-compliance by the obvious facts of cultural differences, but I argue that it should be understood by institutional practices that exclude families from participating in caretaking. I maintain that patients and families should be included in decisions that affect their lives. Pressures from government to economize by increasing home care services, and the increasing number of immigrants may force practitioners to negotiate culturally acceptable care with them.

Title: Ethnicity and illness experience: Ideological structures and the health care delivery system

Subject headings: ethnicity; illness experience; ideology

Year: 1986

Publication: Social Science & Medicine

Volume: 22

Issue: 11

Pages: 1277-1283

Full text: http://www.sciencedirect.com/science/article/pii/0277953686901954

Cited by: https://scholar.google.com/scholar?cites=15132363342533435731&as_sdt=1000005&sciodt=0,16&hl=en

Format: Journal Article

ISSN: 0277-9536

ISBN:
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Author: Anderson, J.W.; Nicolosi, R.J.; Borzelleca, J.F.

Description: Glucosamine is widely used to relieve symptoms from osteoarthritis. Its safety and effects on glucose metabolism are critically evaluated in this review. The LD50 of oral glucosamine in animals is approximately 8000 mg/kg with no adverse effects at 2700 mg/kg for 12 months. Because altered glucose metabolism can be associated with parenteral administration of large doses of glucosamine in animals and with high concentrations in in vitro studies, we critically evaluated the clinical importance of these effects. Oral administration of large doses of glucosamine in animals has no documented effects on glucose metabolism. In vitro studies demonstrating effects of glucosamine on glucose metabolism have used concentrations that are 100-200 times higher than tissue levels expected with oral glucosamine administration in humans. We reviewed clinical trial data for 3063 human subjects. Fasting plasma glucose values decreased slightly for subjects after oral glucosamine for approximately 66 weeks. There were no adverse effects of oral glucosamine administration on blood, urine or fecal parameters. Side effects were significantly less common with glucosamine than placebo or non-steroidal anti-inflammatory drugs (NSAID). In contrast to NSAID, no serious or fatal side effects have been reported for glucosamine. Our critical evaluation indicates that glucosamine is safe under current conditions of use and does not affect glucose metabolism.

Title: Glucosamine effects in humans: a review of effects on glucose metabolism, side effects, safety considerations and efficacy

Subject headings: Administration, Oral; Animals; Blood Glucose/*drug effects/metabolism; Clinical Trials as Topic; Glucosamine/*adverse effects/pharmacokinetics/therapeutic use; Humans; Infusions, Parenteral; Lethal Dose 50; Metabolic Clearance Rate; Osteoarthritis/*drug therapy; Safety; Toxicity Tests; Treatment Outcome

Year: 2005

Publication: Food and Chemical Toxicology : an International Journal Published for the British Industrial Biological Research Association

Volume: 43

Issue: 2

Pages: 187-201

Full text: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.548.5514&rep=rep1&type=pdf

Cited by: https://scholar.google.com/scholar?cites=14219541644719086106&as_sdt=1000005&sciodt=0,16&hl=en

Format: Journal Article

ISSN: 0278-6915

ISBN:
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Author: Anderson, K.J.

Description: According to the Yerkes-Dodson law, performance is an inverted-U function of arousal with a negative relationship between optimal arousal and task difficulty. Both easy (letter cancellation) and difficult (verbal abilities) tasks were completed during the morning by 100 subjects differing in impulsivity; each subject was tested with five different doses of caffeine. Data were subjected to a traditional analysis of variance; in addition, data from individual subjects were analyzed. Group-level results indicated that performance was an interactive function of task, caffeine, and impulsivity (P<0.05): As predicted by the Yerkes-Dodson law, performance on the easy task tended to improve as caffeine dosage increased, but on the difficult task, (less aroused) impulsive subjects improved while (more aroused) nonimpulsive subjects first improved and then deteriorated. Moreover, analyses of the performance of individual subjects strongly supported the inverted-U hypothesis (P<0.001). The hypothesis that easier tasks require higher levels of arousal for optimal performance than more difficult tasks received limited support at the individual level. Thus, despite methodological and probabilistic biases against the inverted-U and task-difficulty hypotheses, both group and individual level analyses yielded results consistent with the Yerkes-Dodson law.

Title: Impulsitivity, caffeine, and task difficulty: A within-subjects test of the Yerkes-Dodson law

Subject headings: Yerkes-Dodsonn Law; Performance; Arousal; Task difficulty; Inverted-U

Year: 1994

Publication: Personality and Individual Differences

Volume: 16

Issue: 6

Pages: 813-829

Full text: http://linkinghub.elsevier.com/retrieve/pii/0191886994902267

Cited by: https://scholar.google.com/scholar?cites=9373169926091372218&as_sdt=1000005&sciodt=0,16&hl=en

Format: Journal Article

ISSN: 0191-8869

ISBN:
Details

Author: Anderson, L.M.; Scrimshaw, S.C.; Fullilove, M.T.; Fielding, J.E.; Normand, J.

Description: Culturally competent healthcare systems-those that provide culturally and linguistically appropriate services-have the potential to reduce racial and ethnic health disparities. When clients do not understand what their healthcare providers are telling them, and providers either do not speak the client's language or are insensitive to cultural differences, the quality of health care can be compromised. We reviewed five interventions to improve cultural competence in healthcare systems-programs to recruit and retain staff members who reflect the cultural diversity of the community served, use of interpreter services or bilingual providers for clients with limited English proficiency, cultural competency training for healthcare providers, use of linguistically and culturally appropriate health education materials, and culturally specific healthcare settings. We could not determine the effectiveness of any of these interventions, because there were either too few comparative studies, or studies did not examine the outcome measures evaluated in this review: client satisfaction with care, improvements in health status, and inappropriate racial or ethnic differences in use of health services or in received and recommended treatment.

Title: Culturally competent healthcare systems. A systematic review

Subject headings: Communication Barriers; Cultural Diversity; *Culture; *Delivery of Health Care; Health Personnel; Humans; Language; Outcome and Process Assessment (Health Care); Quality of Health Care; United States

Year: 2003

Publication: American Journal of Preventive Medicine

Volume: 24

Issue: 3 Suppl

Pages: 68-79

Full text: https://pdfs.semanticscholar.org/3bf9/b7679963534dce1e29d9919bd5bb1dd7836f.pdf

Cited by: https://scholar.google.com/scholar?cites=14325306486069015612&as_sdt=1000005&sciodt=0,16&hl=en

Format: Journal Article

ISSN: 0749-3797

ISBN:
Details

Author: Anderson, M.G.; Burt, T.P.

Description: A laboratory slope drainage model is constructed in order to test results obtained by Hewlett and Hibbert who have suggested unsaturated flow to be the dominant flow mechanism at the later stages of drainage. The results from the model, together with hydraulic conductivity determinations, indicate the slope discharge to be controlled by saturated flow throughout drainage.

Title: A laboratory model to investigate the soil moisture conditions on a draining slope

Subject headings: Drainage; Laboratory slope; Slope discharge; Saturated flow

Year: 1977

Publication: Journal of Hydrology

Volume: 33

Issue: 3-4

Pages: 383-390

Full text: http://linkinghub.elsevier.com/retrieve/pii/0022169477900488

Cited by: https://scholar.google.com/scholar?cites=4241315012861010036&as_sdt=1000005&sciodt=0,16&hl=en

Format: Journal Article

ISSN: 0022-1694

ISBN:
Details

Author: Anderson, N.L.

Description: A report is made of detailed studies carried out on 105 native grassland and abandoned field sites. Measurements of vegetational changes over a 10-year period on one area and field experiments on grasshopper movement involving marked individuals are also reported. The results of the investigations are discussed and evaluated in terms of field observations on grasshopper behavior. Both the taxonomic composition and physical structure of the vegetation are found to play an important role in the selection of areas of occupancy by grasshoppers. There is no evidence to suggest that changes in vegetation are directly responsible for initial fluctuations in population density.

Title: Some Relationships between Grasshoppers and Vegetation

Subject headings:

Year: 1964

Publication: Annals of the Entomological Society of America

Volume: 57

Issue: 6

Pages: 736-742

Full text: https://academic.oup.com/aesa/article-abstract/57/6/736/159867

Cited by: https://scholar.google.com/scholar?cites=9236455183107661798&as_sdt=1000005&sciodt=0,16&hl=en

Format: Journal Article

ISSN: 0013-8746

ISBN:
Details

Author: Anderson, R.S.

Description: Resource partitioning in the silphid fauna of southern Ontario is examined in detail, using baited pitfall traps placed in four different habitats. During 1979 and 1980, a total of 9549 specimens of Silphidae were collected, representing 12 species, of which 5 were in the subfamily Silphinae and 7 in the subfamily Nicrophorinae. The roles of different seasonal patterns, habitat specificity, and food type and size in resource partitioning are discussed for all species. At the subfamilial level, resource partitioning is accomplished through selection of different sizes of carcasses, while at the specific level, seasonal patterns and habitat specificity appear to be the primary means permitting coexistence.In the Silphidae, competition for food resources appears to be the primary factor inducing ecological character displacement. The possible origins of patterns of resource use in this assemblage are discussed in an ecological and geological time framework.

Title: Resource partitioning in the carrion beetle (Coleoptera:Silphidae) fauna of southern Ontario: ecological and evolutionary considerations

Subject headings: Beetle; Silphid fauna; Nicrophorinae

Year: 1982

Publication: Canadian Journal of Zoology

Volume: 60

Issue: 6

Pages: 1314-1325

Full text: http://www.nrcresearchpress.com/doi/abs/10.1139/z82-178#.Wl4mwqinGUk

Cited by: https://scholar.google.com/scholar?cites=1857805381266564446&as_sdt=1000005&sciodt=0,16&hl=en

Format: Journal Article

ISSN: 0008-4301

ISBN:





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