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California Polytechnic State University, San Luis Obispo

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1996

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Articles 1 - 25 of 25

Full-Text Articles in Life Sciences

Long-Term Monitoring And Analyses Of Physical Factors Regulating Variability In Coastal Antarctic Phytoplankton Biomass, In Situ Productivity And Taxonomic Composition Over Subseasonal, Seasonal And Interannual Time Scales, Mark A. Moline, Barbara B. Prezelin Dec 1996

Long-Term Monitoring And Analyses Of Physical Factors Regulating Variability In Coastal Antarctic Phytoplankton Biomass, In Situ Productivity And Taxonomic Composition Over Subseasonal, Seasonal And Interannual Time Scales, Mark A. Moline, Barbara B. Prezelin

Biological Sciences

A 3 yr high-resolution temporal data base related to phytoplankton dynamics was collected during the austral spring/summer periods of 1991 to 1994 in shelf waters adjacent to Palmer Station, Antarctica. Here, the data base is used (1) to quantify the variability in phytoplankton biomass, in situ productivity and taxonomic composition over subseasonal, seasonal and interannual time scales; (2) to elucidate environmental mechanisms controlling these temporal patterns; and (3) to ascertain which phytoplankton markers are most suitable for detecting longer-term (i.e. decadal) trends in phytoplankton dynamics in coastal waters of the Southern Ocean. The Long-Term Ecological Research (LTER) coastal ...


Micronutrients And The Risk Of Colorectal Adenomas, Marilyn Tseng, Sharon C. Murray, Lawrence L. Kupper, Robert S. Sandler Dec 1996

Micronutrients And The Risk Of Colorectal Adenomas, Marilyn Tseng, Sharon C. Murray, Lawrence L. Kupper, Robert S. Sandler

Kinesiology

Recent studies suggest that micronutrients, especially folate, calcium, iron, and antioxidant vitamins, affect the risk of colorectal neoplasia. The objective of this case-control study was to examine the association between these micronutrients and the risk of colorectal adenomas. The study was based on 236 cases with adenomatous polyps or cancer and 409 controls, all colonoscopy patients at University of North Carolina Hospitals between July 1988 and March 1991. After colonoscopy, subjects were interviewed using a semi-quantitative food frequency questionnaire, and average daily nutrient intakes were calculated. Sex-specific odds ratios relative to the lowest quartile of intake for each micronutrient were ...


Genetic And Social Control Of Male Maturation In Phallichthys Quadripunctatus (Pisces: Poeciliidae), Gita R. Kolluru, David N. Reznick Nov 1996

Genetic And Social Control Of Male Maturation In Phallichthys Quadripunctatus (Pisces: Poeciliidae), Gita R. Kolluru, David N. Reznick

Biological Sciences

Age and size at maturity can have significant fitness consequences. Selection often favors early-maturing individuals because of their higher survival to maturity and greater relative contribution to population growth rate, but it may also favor delayed maturation if fitness increases with age or size at maturity. Males of several poeciliid fishes exhibit variation in age and size at maturity primarily controlled by a sex-linked gene called the P-locus. Wild-caught Phallichthys quadripunctatus males show a bimodal size distribution, which is often associated with a P-locus polymorphism in other poeciliids. We conducted two experiments to evaluate the inheritance of male age and ...


High-Resolution Time-Series Data For 1991/1992 Primary Production And Related Parameters At A Palmer Lter Coastal Site: Implications For Modeling Carbon Fixation In The Southern Ocean, Mark A. Moline, Barbara B. Prezelin Nov 1996

High-Resolution Time-Series Data For 1991/1992 Primary Production And Related Parameters At A Palmer Lter Coastal Site: Implications For Modeling Carbon Fixation In The Southern Ocean, Mark A. Moline, Barbara B. Prezelin

Biological Sciences

Our goal was to provide a high-resolution temporal data base for modeling primary production in shelf waters adjacent to Palmer Station, Antarctica. Here, the resulting 1991/1992 data base is used to: (1) determine in situ productivity over a range of seasonal to subseasonal time scales; (2) identify time scales of significant variability in marine productivity during the peak growing season; (3) identify environmental, experimental and analytical factors that can significantly impact the accuracy of daily, weekly and seasonal productivity estimates; and (4) integrate our findings with previous studies of Antarctic coastal primary pro- duction. Data were gathered every 2 ...


Azorhizobium Caulinodans Uses Both Cytochrome Bd (Quinol) And Cytochrome Cbb3 (Cytochrome C) Terminal Oxidases For Symbiotic N2 Fixation, Alexandre Kaminski, Christopher L. Kitts, Zachary Zimmerman, Robert A. Ludwig Oct 1996

Azorhizobium Caulinodans Uses Both Cytochrome Bd (Quinol) And Cytochrome Cbb3 (Cytochrome C) Terminal Oxidases For Symbiotic N2 Fixation, Alexandre Kaminski, Christopher L. Kitts, Zachary Zimmerman, Robert A. Ludwig

Biological Sciences

Azorhizobium caulinodans employs both cytochrome bd (cytbd; quinol oxidase) and cytcbb3 (cytc oxidase) as terminal oxidases in environments with very low O2 concentrations. To investigate physiological roles of these two terminal oxidases both in microaerobic culture and in symbiosis, knockout mutants were constructed. As evidenced by visible absorbance spectra taken from mutant bacteria carrying perfect gene replacements, both the cytbd- and cytcbb3- mutations were null alleles. In aerobic culture under 2% O2 atmosphere, Azorhizobium cytbd- and cytcbb3- single mutants both fixed N2 at 70 to 90% of wild-type rates; in root nodule symbiosis, both single mutants fixed N2 at 50 ...


Mechanical Conditioning For Controlling Excessive Elongation In Tomato Transplants: Sensitivity To Dose, Frequency, And Timing Of Brushing, Lauren C. Garner, Thomas Björkman Sep 1996

Mechanical Conditioning For Controlling Excessive Elongation In Tomato Transplants: Sensitivity To Dose, Frequency, And Timing Of Brushing, Lauren C. Garner, Thomas Björkman

Horticulture and Crop Science

During production of plug transplants, the high plant density results in rapid stem elongation as plants compete for light. The resulting tall, weak-stemmed plants are difficult to transplant and are easily damaged. One technique that can prevent excessive elongation is mechanical stimulation by brushing. Wide adoption of brushing is limited by a lack of information on how plants respond to variations in applying the technique. Our investigation examined how tomato (Lycopersicon esculentum cv. Oh8245) seedling growth responded to varying doses of mechanical stimulation, varying intervals between brush strokes during stimulation, time of day that stimulation was applied, and growth stage ...


High-Power Broadly Tunable Picosecond Ir Laser System For Use In Nonlinear Spectroscopic Applications, D. E. Gragson, B. M. Mccarty, G. L. Richmond, D. S. Alavi Sep 1996

High-Power Broadly Tunable Picosecond Ir Laser System For Use In Nonlinear Spectroscopic Applications, D. E. Gragson, B. M. Mccarty, G. L. Richmond, D. S. Alavi

Chemistry and Biochemistry

We developed a high-power tunable picosecond IR laser system suitable for nonlinear spectroscopic investigations. We employ a Ti:sapphire regenerative amplifier that produces 1.9-ps, 17-cm−1, 800-nm pulses at 1 kHz as a pump source. White-light generation in ethylene glycol and optical parametric amplification in potassium titanyl phosphate are used to produce the IR pulses. The tuning range extends from 2.4 to 3.8 μm in the idler and 1.0 to 1.2 μm in the signal. A total efficiency (signal plus idler) as high as 20% was achieved. The spatial, spectral, and temporal characteristics of the ...


Expression Of A Bovine Κ-Cn Cdna In The Mammary Gland Of Transgenic Mice Utilizing A Genomic Milk Protein Gene As An Expression Cassette, Alfonso Gutiérrez, Harry M. Meade, Paul Ditullio, Daniel Pollock, Merry Harvey, Rafael Jiménez-Flores, Gary B. Anderson, James D. Murray, Juan F. Medrano Jul 1996

Expression Of A Bovine Κ-Cn Cdna In The Mammary Gland Of Transgenic Mice Utilizing A Genomic Milk Protein Gene As An Expression Cassette, Alfonso Gutiérrez, Harry M. Meade, Paul Ditullio, Daniel Pollock, Merry Harvey, Rafael Jiménez-Flores, Gary B. Anderson, James D. Murray, Juan F. Medrano

Dairy Science

Transgenic mice were produced by microinjection of a DNA construct composed of the bovine κ-casein (κ-CN) cDNA under the control of the goat β-CN 5' promoter elements and 3' flanking regions into pronuclear-stage embryos. The gene construct targeted the expression of bovine κ-CN RNA to the mammary gland and secretion of bovine κ-CN in the milk. In the three lines studied (BC-7, BC-31 and BC-67) the transgene was stably integrated and propagated as a Mendelian locus. Expression of the bovine protein in lactating mice from the three transgenic lines was demonstrated by northern and western blots. In ten different tissues ...


Issues Concerning The Eradication Or Establishment And Biological Control Of The Mediterranean Fruit Fly, Ceratitis Capitata(Wiedemann) (Diptera: Tephritidae), In California, David H. Headrick, Richard D. Goeden Jun 1996

Issues Concerning The Eradication Or Establishment And Biological Control Of The Mediterranean Fruit Fly, Ceratitis Capitata(Wiedemann) (Diptera: Tephritidae), In California, David H. Headrick, Richard D. Goeden

Horticulture and Crop Science

Classical biological control is suggested as a tool worth developing now for possible future use in the integrated pest management of the Mediterranean fruit fly (Medfly), Ceratitis capitata (Wiedemann), in California. Three factors that impact broadly on developing and implementing such a biological control program are: (1) the question of Medfly establishment, (2) quarantine considerations, and (3) agricultural and urban concerns. Each of these factors and their combined effects must be considered when discussing biological control of Medfly in California as shaped by historical perspectives on Medfly invasions, methods of Medfly eradication, and past biological control efforts against Medfly. We ...


Two Erroneous, Commonly Cited Examples Of "Swordfish" Piercing Wooden Ships, Harry L. Fierstine, Oliver Crimmen May 1996

Two Erroneous, Commonly Cited Examples Of "Swordfish" Piercing Wooden Ships, Harry L. Fierstine, Oliver Crimmen

Biological Sciences

No abstract provided.


Critical Pressures In Multicomponent Lipid Monolayers, John P. Hagen, Harden M. Mcconnell Apr 1996

Critical Pressures In Multicomponent Lipid Monolayers, John P. Hagen, Harden M. Mcconnell

Chemistry and Biochemistry

Epifluorescence microscopy has been used previously to study coexisting liquid phases in lipid monolayers of dihydrocholesterol and dimyristoylphosphatidylcholine at the air/water interface. This binary mixture has a critical point at room temperature (22°C), a monolayer pressure of approx. 10 mN/m, and a composition in the vicinity of 20-30 mol% dihydrocholesterol. It is reported here that this critical pressure can be lowered, raised, or maintained constant by systematically replacing molecules of this phosphatidylcholine with molecules of a phosphatidylethanolamine, or an unsaturated phosphatidylcholine, or mixtures of the two, while maintaining the dihydrocholesterol concentration at 20 mol%. Thus, even complex ...


Host-Plant Effects On The Behavior Of Eretmocerus Sp. Nr. Californicus Females Raised From Melon, David H. Headrick, Thomas S. Bellows, Jr., Thomas M. Perring Mar 1996

Host-Plant Effects On The Behavior Of Eretmocerus Sp. Nr. Californicus Females Raised From Melon, David H. Headrick, Thomas S. Bellows, Jr., Thomas M. Perring

Horticulture and Crop Science

The behaviors of female Eretmocerus sp. nr. californiens raised from Bemisia argentifolii Bellows & Perring on melon, Cucumis melo L., were analysed on four different host plant species (cotton, melon, sweet potato and Abutilon theophrasti Medic). Comparison with previously published results of similarly treated females reared from sweet potato plants showed performance related differences leading to oviposition. In the present study, the generalized behavioral pathway (walking, host- encounter, antennation, probing and oviposition) did not vary among host plant species for melon- reared parasitoid females. Host assessment by antennation leading to host acceptance for probing varied from 10.5- 12.3 sec ...


Efficacy Of Herbicide Application Methods Used To Control Tanoak (Lithocarpus Densiflorus) In An Uneven-Aged Coast Redwood Management Context, Douglas D. Piirto, Brenda Smith, Eric K. Huff, Scott T. Robinson Mar 1996

Efficacy Of Herbicide Application Methods Used To Control Tanoak (Lithocarpus Densiflorus) In An Uneven-Aged Coast Redwood Management Context, Douglas D. Piirto, Brenda Smith, Eric K. Huff, Scott T. Robinson

Natural Resources Management and Environmental Sciences

Three methods of tanoak (Lithocarpus densiflorus [Hook. & Arn.] Rehd.) control involving the application of the amine or ester form of triclopyr were evaluated in this coast redwood uneven-aged forest management study of herbicides. A cut-stump application with the amine form of triclopyr (Garlon 3A), frill cut with the amine form of triclopyr, basal-bark (outer surface) with the ester form of triclopyr (Garlon 4), and an untreated control were replicated three times. The tanoak control results in Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) and/ or coast redwood (Sequoia sempervirens [D. Don] Endl.) predominated stands obtained in earlier studies in northern California and ...


Use Of Rostral Characters For Identifying Adult Billfishes (Teleostei: Perciformes: Istiophoridae And Xiphiidae), Harry L. Fierstine, Nicole L. Voigt Feb 1996

Use Of Rostral Characters For Identifying Adult Billfishes (Teleostei: Perciformes: Istiophoridae And Xiphiidae), Harry L. Fierstine, Nicole L. Voigt

Biological Sciences

Seven species of the family Istiophoridae and Xiphias gladiu6 were identified using only features of their rostrum. In the Istiophoridae, two rostral regions were emphasized, one-fourth and one·half the distance between the distal tip and the orbital margin of the lateral ethmoid bone. Characters studied in each region were the depth and width of rostrum and height, width, and position of nutrient canals (as seen in cross-section). Characters studied without reference to region were the distribution of denticles on both dorsal and ventral surfaces of the bilI and position of the prenasal bone. In the Xiphiidae, the only characters ...


Behaviors Of Female Eretmocerus Sp. Nr. Californicus (Hymenoptera: Aphelinidae) Attacking Bemisia Argentifolii (Homoptera: Aleyrodidae) On Cotton, Gossypium Hirsutum, (Malavaceae) And Melon, Cucumis Melo (Cucurbitaceae), David H. Headrick, Thomas S. Bellows, Jr., Thomas M. Perring Feb 1996

Behaviors Of Female Eretmocerus Sp. Nr. Californicus (Hymenoptera: Aphelinidae) Attacking Bemisia Argentifolii (Homoptera: Aleyrodidae) On Cotton, Gossypium Hirsutum, (Malavaceae) And Melon, Cucumis Melo (Cucurbitaceae), David H. Headrick, Thomas S. Bellows, Jr., Thomas M. Perring

Horticulture and Crop Science

Behaviors of Eretmocerus sp. nr. californicus females attacking Bemisia argentifolii Bellows & Perring infesting cotton, Gossypium hirsutum L., and melon, Cucumis melo L., were quantified. Adult female behaviors were described and quantified for Eret. sp. nr. californicus to establish a behavioral time budget analysis. Females readily searched for host whitefly nymphs on cotton leaves with walking speeds averaging 0.5 mm/s. Females remained infrequently on melon leaves; those that did remain and search for hosts averaged walking speeds of 0.33 mm/s. The duration of host assessment by antennation was related to subsequent behaviors. Rejecting a host was a shorter process than accepting it for further evaluation irrespective of plant species or nymphal stage. Probing the margins of the host nymph the ovipositor was repeated less frequently on an individual host on melon leaves than on cotton. Evidence for a behavioral preference for oviposition under early instars was documented for Eret. sp. nr. californicus females ...


Trade-Offs In Parasitology, Evolution And Behavior, Marlene Zuk, M. J. Bryant, Gita R. Kolluru, V. Mirmovitch Feb 1996

Trade-Offs In Parasitology, Evolution And Behavior, Marlene Zuk, M. J. Bryant, Gita R. Kolluru, V. Mirmovitch

Biological Sciences

No abstract provided.


An Improved Synthesis Of 2-(Hydroxymethyl)Indene, Hasan Palandoken, William T. Mcmillen, Michael H. Nantz Jan 1996

An Improved Synthesis Of 2-(Hydroxymethyl)Indene, Hasan Palandoken, William T. Mcmillen, Michael H. Nantz

Chemistry and Biochemistry

No abstract provided.


Descriptions Of Immature Stages Of Trupanea Nigricornis And T. Bisetosa (Diptera: Tephritidae) From Southern California, Khouzama M. Knio, Richard D. Goeden, David H. Headrick Jan 1996

Descriptions Of Immature Stages Of Trupanea Nigricornis And T. Bisetosa (Diptera: Tephritidae) From Southern California, Khouzama M. Knio, Richard D. Goeden, David H. Headrick

Horticulture and Crop Science

The immature stages of the sympatric, cryptic species Trupanea nigricornis (Coquillett), a flower head-infesting fruit fly that attacks a wide range of hosts in the Asteraceae in southern California, and T. bisetosa (Coquillett), an oligophagous congener that attacks only a few hosts in the tribe Heliantheae, are described and illustrated. Detailed examination with the aid of scanning electron microscopy of the eggs, all 3 instars, and puparia of this taxonomically closely allied generalist and specialist revealed many similarities and very few differences, for instance, most puparia of T. nigricornis were shorter and narrower than those of T. bisetosa. Therefore, major ...


Description Of The Male Ceranisus Americensis (Girault) (Hymenoptera: Eulophidae), Serguei V. Triapitsyn, David H. Headrick Jan 1996

Description Of The Male Ceranisus Americensis (Girault) (Hymenoptera: Eulophidae), Serguei V. Triapitsyn, David H. Headrick

Horticulture and Crop Science

No abstract provided.


Commercial Adaptations Of Mechanical Stimulation For The Control Of Transplant Growth, Lauren C. Garner, Allen F. Langton, Thomas Bjorkman Jan 1996

Commercial Adaptations Of Mechanical Stimulation For The Control Of Transplant Growth, Lauren C. Garner, Allen F. Langton, Thomas Bjorkman

Horticulture and Crop Science

The commercial use of mechanical stimulation to control transplant growth is quite limited. To be commercially successful, the technique must be simple and flexible, and must not reduce plant quality. Brushing was applied to tomato (Lycopersicon esculentum) seedlings growing at a density of 2100 plants m-2 by daily stroking with a piece of polystyrene. Ten or twenty daily strokes typically provided significant height control without plant damage. Increasing the interval between strokes to up to 10 minutes resulted in the same amount of height control as continuous brushing. There were typically no differences between treating the plants at 0800 ...


Comparative Biologies Of The Cryptic, Sympatric Species, Trupanea Bisetosa And T. Nigricornis (Diptera: Tephritidae) In Southern California, Khouzama M. Knio, Richard D. Goeden, David H. Headrick Jan 1996

Comparative Biologies Of The Cryptic, Sympatric Species, Trupanea Bisetosa And T. Nigricornis (Diptera: Tephritidae) In Southern California, Khouzama M. Knio, Richard D. Goeden, David H. Headrick

Horticulture and Crop Science

The biologies of the sympatric, cryptic species, Trupanea nigricornis (Coquillett), a flower head-infesting fruit fly attacking a wide range of hosts in 8 tribes, 33 genera, and at least 71 species of Asteraceae, and T. bisetosa (Coquillett), an oligophage attacking only 6 hosts in 4 genera of the tribe Heliantheae, are described and compared. A major biological distinction between these species was their ovipositional behavior, whereby females oviposited different numbers of eggs at different sites in different developmental stages of flower heads of their hosts. The larvae of these species showed minor differences in their feeding behaviors, and their puparia ...


Analysing Ancient Dna, Raúl J. Cano Jan 1996

Analysing Ancient Dna, Raúl J. Cano

Biological Sciences

Much of what we know about extinct organisms comes from traits that are not preserved in the fossil record. Until recently, morphological analysis was the only tool available for scientists to determine relationships for extinct fossil organisms. We now know that ‘ancient’ DNA can be preserved in the remains of extinct organisms. By targeting specific gene sequences, it may be possible to deduce biochemical characteristics and through sequence comparisons, to estimate the extent of evolutionary divergence. By comparing the amount and type of these changes, one could estimate how quickly some DNA ‘evolves’ relative to other segments, or which genes ...


Effect Of Larval Swimming Duration On Success Of Metamorphosis And Size Of The Ancestrular Lophophore In Bugula Neritina (Bryozoa), Dean E. Wendt Jan 1996

Effect Of Larval Swimming Duration On Success Of Metamorphosis And Size Of The Ancestrular Lophophore In Bugula Neritina (Bryozoa), Dean E. Wendt

Biological Sciences

There is a growing realization that events during one portion of an organism's life cycle can have both subtle and dramatic effects on other stages in the life history. Lethal and sublethal effects associated with the duration of larval swimming in marine invertebrates were examined for the bryozoan Bugula neritina. Larvae were kept swimming up to a maximum of 28 h at 20{deg}C by exposure to continuous bright fluorescent illumination. At 4-h intervals, samples of 20-40 larvae were removed from bright illumination and were exposed to seawater containing 10 mM excess KCI, an inducer of metamorphosis in ...


Temporal Dynamics Of Coastal Antarctic Phytoplankton: Environmental Driving Forces And Impact Of 1991/92 Summer Diatom Bloom On The Nutrient Regimes, Mark A. Moline, Barbara B. Prezelin, Oscar Schofield, Raymond C. Smith Jan 1996

Temporal Dynamics Of Coastal Antarctic Phytoplankton: Environmental Driving Forces And Impact Of 1991/92 Summer Diatom Bloom On The Nutrient Regimes, Mark A. Moline, Barbara B. Prezelin, Oscar Schofield, Raymond C. Smith

Biological Sciences

Within the Palmer Long Term Ecological Research Program (PAL-LTER), a suite of environmental data sets were collected at a nearshore station throughout the 1991/92 austral summer. Seasonal changes are presented in the context of phytoplankton community ecology. Subseasonal fluctuations in sea-ice coverage, freshwater inputs, as well as wind driven and advective processes disrupting stratified surface waters, appeared to be the major driving forces affecting the timing, duration and demise of local phytoplankton blooms. During a large diatom-dominated bloom (~30 mg chl a m-3), macronutrients were depleted to detection limits (NO3--3, PO4-3< 0.03 mmol m-3) and significant ...


Light-Saturated Primary Production In Antarctic Coastal Waters, Mark A. Moline, Barbara B. Prezelin, Herve Claustre Jan 1996

Light-Saturated Primary Production In Antarctic Coastal Waters, Mark A. Moline, Barbara B. Prezelin, Herve Claustre

Biological Sciences

No abstract provided.