Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

California Polytechnic State University, San Luis Obispo

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1921 - 1950 of 2151

Full-Text Articles in Life Sciences

Evaluation Of Commercial Adjuncts For Use In Cheese Ripening: 3. Properties Of Heat-Shocked Adjuncts In Buffer And Cheese Slurry Systems, M. El-Soda, S. A. Madkor, P. S. Tong Jan 1999

Evaluation Of Commercial Adjuncts For Use In Cheese Ripening: 3. Properties Of Heat-Shocked Adjuncts In Buffer And Cheese Slurry Systems, M. El-Soda, S. A. Madkor, P. S. Tong

Dairy Science

No abstract provided.

Go to article

Exploitations Of Sexual Signals By Predators And Parasitoids, Marlene Zuk, Gita R. Kolluru Dec 1998

Exploitations Of Sexual Signals By Predators And Parasitoids, Marlene Zuk, Gita R. Kolluru

Biological Sciences

Signals used to attract mates are often conspicuous to predators and parasites, and their evolution via sexual selection is expected to be opposed by viability selection. Many secondary sexual traits may represent a compromise between attractiveness and avoidance of detection. Although such signal exploitation appears to be widespread, most examples come from species that use acoustic or olfactory mating signals, and relatively few cases of visual signal exploitation can be substantiated. Because males are usually the signaling sex, they are more at risk from predators or parasitoids that locate prey or hosts by sexual signals; this differential selection on the …

Go to article

Sex Can Be Dangerous: Acoustically-Orienting Parasitoids On Field Crickets (Orthoptera: Gryllidae), Gita R. Kolluru Dec 1998

Sex Can Be Dangerous: Acoustically-Orienting Parasitoids On Field Crickets (Orthoptera: Gryllidae), Gita R. Kolluru

Biological Sciences

The Orthopterists' Society generously awarded me grants in 1995 and 1997 to conduct research on Teleogryllus oceanicus (Orthoptera: Gryllidae) on the Big Island of Hawaii. Here I report results to date from fieldwork conducted in the past few years.

Go to article

Photosynthetic Parameters And Empirical Modeling Of Primary Production: A Case Study On The Antarctic Peninsula Shelf, Mark A. Moline, Oscar Schofield, Nicolas P. Boucher Nov 1998

Photosynthetic Parameters And Empirical Modeling Of Primary Production: A Case Study On The Antarctic Peninsula Shelf, Mark A. Moline, Oscar Schofield, Nicolas P. Boucher

Biological Sciences

Eight hundred photosynthesis-irradiance relationships were determined in the shelf waters adjacent to Palmer Station, Antarctica during the spring/summer periods of 1991–94. Biomass specific maximum photosynthetic rate, PBmax, and the light limited photosynthetic efficiency, αB, were poorly correlated to the physical forcing and nutrient regimes at the sampling stations. The two photosynthetic parameters, however, did strongly covary indicating the minimum irradiance required to saturate photosynthesis, Ik, was relatively constant in this highly variable environment. The variability in Ik could partially be attributed to both depth in the water column and time of the …

Go to article

Rostral-Caudal Variation In Troponin T And Parvalbumin Correlates With Differences In Relaxation Rates Of Cod Axial Muscle, Tierney M. Thys, Jason M. Blank, Fred H. Schachat Nov 1998

Rostral-Caudal Variation In Troponin T And Parvalbumin Correlates With Differences In Relaxation Rates Of Cod Axial Muscle, Tierney M. Thys, Jason M. Blank, Fred H. Schachat

Biological Sciences

Relaxation rate is an important determinant of axial muscle power production during the oscillatory contractions of undulatory locomotion. Recently, significant differences have been reported in the relaxation rates of rostral versus caudal white muscle fibers of the Atlantic cod Gadus morhua L. The present study investigates the biochemical correlates of this rostral-caudal physiological variation. Using denaturing gel electrophoresis, a series of fresh muscle samples from the dorsal epaxial muscle region was analyzed and several differences were detected. First, a gradual shift occurs in the expression of two troponin T isoforms along the length of the body. Second, rostral muscles were …

Go to article

Metamorphis Is Not A New Beginning, Jan A. Pechenik, Dean E. Wendt, Jeremiah N. Jarrett Nov 1998

Metamorphis Is Not A New Beginning, Jan A. Pechenik, Dean E. Wendt, Jeremiah N. Jarrett

Biological Sciences

No abstract provided.

Go to article

Sequence Analysis Of Bacterial Dna In The Colon Of An Andean Mummy, Massimo Ubaldi, Stefania Luciani, Isolina Marota, Gino Fornaciari, Raul J. Cano, Franco Rollo Nov 1998

Sequence Analysis Of Bacterial Dna In The Colon Of An Andean Mummy, Massimo Ubaldi, Stefania Luciani, Isolina Marota, Gino Fornaciari, Raul J. Cano, Franco Rollo

Biological Sciences

We have isolated DNA from 14 tissue samples from the internal organs of an Andean human mummy (10th–11th century A.D.) and have checked the persistence of the original human and bacterial templates using the following main approaches: 1) amino acid racemization test; 2) quantification of mitochondrial DNA copy number; 3) survey of bacterial DNA in the different organs; 4) sequence analysis of bacterial amplicons of different lengths. The results demonstrate that both the original human DNA and the DNA of the bacteria of the mummy gut are preserved. In particular, sequence analysis of two (respectively 100 and 196 bp in …

Go to article

Effect Of Larval Swimming Duration On Growth And Reproduction Of Bugula Neritina (Bryozoa) Under Field Conditions, Dean E. Wendt Oct 1998

Effect Of Larval Swimming Duration On Growth And Reproduction Of Bugula Neritina (Bryozoa) Under Field Conditions, Dean E. Wendt

Biological Sciences

A growing body of evidence indicates that even subtle events occurring during one portion of an animal's life cycle can have detrimental, and in some cases, lasting effects on later stages. Using a laboratory-field transplant design, postmetamorphic costs associated with the duration of larval swimming were investigated in the bryozoan Bugula neritina. Larvae were induced to metamorphose in the laboratory after swimming for either less than 1 h or between 23 and 24 h; colonies that developed from these two groups of larvae are referred to hereafter as "1-h colonies" and "24-h colonies," respectively. After completing metamorphosis, individuals were …

Go to article

Can Cover Crops Reduce Leafhopper Abundance In Vineyards?, Kent M. Daane, Michael J. Costello Sep 1998

Can Cover Crops Reduce Leafhopper Abundance In Vineyards?, Kent M. Daane, Michael J. Costello

Horticulture and Crop Science

In 3 of 4 vineyards we studied, late-season leafhopper density was lower on vines in cover cropped plots than in plots with no cover crops. However, the level of leafhopper reduction (about 15%) was rarely economically important and the mechanisms leading to reduction were not clear. For example, there were few differences in the number of leaf hopper predators or parasitoids on the vines in cover cropped versus no cover plots. However, there were significant between-treatment differences in vine growth. Plots with seasonwide maintenance of a cover crop and resident grasses had a reduction in vine vigor. Lower vine vigor …

Go to article

Rapid Detection Of Listeria Monocytogenes In Dairy Samples Utilizing A Pcr-Based Fluorogenic 5′ Nuclease Assay, T. Cox, C. Frazier, J. Tuttle, S. Flood, L. Yagi, C. T. Yamashiro, R. Behari, C. Paszko, R. J. Cano Sep 1998

Rapid Detection Of Listeria Monocytogenes In Dairy Samples Utilizing A Pcr-Based Fluorogenic 5′ Nuclease Assay, T. Cox, C. Frazier, J. Tuttle, S. Flood, L. Yagi, C. T. Yamashiro, R. Behari, C. Paszko, R. J. Cano

Biological Sciences

The presence of Listeria monocytogenes as a dairy food contaminant is a lethal threat to dairy industrialists; therefore, products tainted with L. monocytogenes must be quickly detected and removed from production. This fluorogenic PCR-based assay was developed to rapidly detect L. monocytogenes contamination in dairy samples before a final product is distributed. The detection method employed uses a PCR primer pair and a fluorogenic TaqMan probe which bind to a region of a virulence determinant gene specific to L. monocytogenes. As the DNA target is amplified, the 5′ nuclease activity of Taq DNA polymerase hydrolyzes the internal fluorogenic probe …

Go to article

Is Population Genetics Mired In The Past?, Andrew J. Bohonak, Neil Davies, George K. Roderick, Francis X. Villablanca Sep 1998

Is Population Genetics Mired In The Past?, Andrew J. Bohonak, Neil Davies, George K. Roderick, Francis X. Villablanca

Biological Sciences

No abstract provided.

Go to article

Whey Protein Edible Film Structures Determined By Atomic Force Microscope, L.E. Lent, L. S. Vanasupa, P. S. Tong Sep 1998

Whey Protein Edible Film Structures Determined By Atomic Force Microscope, L.E. Lent, L. S. Vanasupa, P. S. Tong

Dairy Science

Atomic force microscopy was used to study edible films produced from whey proteins. The films were imaged under ambient conditions with no special sample preparation. Low resolution imaging of areas from 10 μm to 150 μm on a side was performed in the contact mode. Higher resolution scans of 350 nm to 2,700 nm required use of the noncontact imaging mode. Features about the same size as the primary protein in whey, beta-lactoglobulin (7 nm), were identified in the film samples. Molecular aggregates in the range of 1 μm, reported in other studies using transmission electron microscopy of whey protein …

Go to article

Identification Of A Functional Homolog Of The Yeast Copper Homeostasis Gene Atx1 From Arabidopsis, Edward Himelblau, Helena Mria, Su-Ju Lin, Valeria Cizewski Culotta, Lola Penarrubia, Richard M. Amasino Aug 1998

Identification Of A Functional Homolog Of The Yeast Copper Homeostasis Gene Atx1 From Arabidopsis, Edward Himelblau, Helena Mria, Su-Ju Lin, Valeria Cizewski Culotta, Lola Penarrubia, Richard M. Amasino

Biological Sciences

A cDNA clone encoding a homolog of the yeast (Saccharomyces cerevisiae) gene Anti-oxidant 1 (ATX1) has been identified from Arabidopsis. This gene, referred to as Copper CHaperone (CCH), encodes a protein that is 36% identical to the amino acid sequence of ATX1 and has a 48-amino acid extension at the C-terminal end, which is absent from ATX1 homologs identified in animals. ATX1-deficient yeast (atx1) displayed a loss of high-affinity iron uptake. Expression of CCH in the atx1 strain restored high-affinity iron uptake, demonstrating that CCH is a functional homolog of ATX1 …

Go to article

Genetic Admixture And Gallbladder Disease In Mexican Americans, Marilyn Tseng, Robert C. Williams, Kurt R. Maurer, Moses S. Schanfield, William C. Knowler, James E. Everhart Jul 1998

Genetic Admixture And Gallbladder Disease In Mexican Americans, Marilyn Tseng, Robert C. Williams, Kurt R. Maurer, Moses S. Schanfield, William C. Knowler, James E. Everhart

Kinesiology and Public Health

Gallbladder disease is a common source of morbidity in the Mexican American population. Genetic heritage has been proposed as a possible contributor, but evidence for this is limited. Because gallbladder disease has been associated with Native American heritage, genetic admixture may serve as a useful proxy for genetic susceptibility to the disease in epidemiologic studies. The objective of our study was to examine thepossibility that gallbladder disease is associated with greater Native American admixture in Mexican Americans. This study used data from the Hispanic Health and Nutrition Examination Survey and was based on 1,145 Mexican Americans who underwent gallbladder ultrasonography …

Go to article

Invasion Genetics Of The Mediterranean Fruit Fly: Variation In Multiple Nuclear Introns, F. X. Villablanca, G. K. Roderick, S. R. Palumbi May 1998

Invasion Genetics Of The Mediterranean Fruit Fly: Variation In Multiple Nuclear Introns, F. X. Villablanca, G. K. Roderick, S. R. Palumbi

Biological Sciences

Biological invasions generally start from low initial population sizes, leading to reduced genetic variation in nuclear and especially mitochondrial DNA. Consequently, genetic approaches for the study of invasion history and population structure are difficult. An extreme example is the Mediterranean fruit fly, Ceratitis capitata (Medfly), for which successive invasions during this century have resulted in a loss of 60% of ancestral genetic variation in isozymes and 75% of variation in mitochondrial DNA. Using Medflies as an example, we present a new approach to invasion genetics that measures DNA sequence variation within introns from multiple nuclear loci. These loci are so …

Go to article

Staphylococcus Succi Nus Sp. Nov., Isolated From Dominican Amber, L. H. Lambert, T. Cox, K. Mitchell, R. A. Rosselló-Mora, C. Del Cueto, D. E. Dodge, P. Orkand, R. J. Cano Apr 1998

Staphylococcus Succi Nus Sp. Nov., Isolated From Dominican Amber, L. H. Lambert, T. Cox, K. Mitchell, R. A. Rosselló-Mora, C. Del Cueto, D. E. Dodge, P. Orkand, R. J. Cano

Biological Sciences

Two bacterial isolates, designated AMG-D1Tand AMG-D2, were recovered from 25-35-million-year-old Dominican amber. AMG-D1Tand AMG-D2 biochemically most closely resemble Staphylococcus xylosus; they differ physiologically from other staphylococci. Fatty acid analysis and comparisons with extensive databases were unable to show relatedness to any specific taxon. Moreover, AMG-D1Tand AMG-D2 contain tuberculostearic acid and meso-diaminopimelic acid, characteristic of the G+C-rich coryneform bacteria, as opposed to L-lysine characteristic of staphylococci. AMG-D1Tand AMG-D2 have a G+C ratio of 35 mol%. Phylogenetic analysis with the 16S rRNA gene indicated that AMG-D1Tand AMG-D2 were most closely …

Go to article

Terminal Restriction Fragment Patterns (Trfps), A Rapid, Pcr-Based Method For The Comparison Of Complex Bacterial Communities, Brian G. Clement, Lucia E. Kehl, Kristin L. Debord, Christopher L. Kitts Jan 1998

Terminal Restriction Fragment Patterns (Trfps), A Rapid, Pcr-Based Method For The Comparison Of Complex Bacterial Communities, Brian G. Clement, Lucia E. Kehl, Kristin L. Debord, Christopher L. Kitts

Biological Sciences

Microbial populations in complex environmental samples are difficult to characterize; current techniques are incomplete and time consuming. We investigated a polymerase chain reaction (PCR)-based method for rapidly comparing bacterial communities independent of culture or cloning. Community 16S rRNA genes were amplified and fluorescently labeled by PCR. The labeled products were digested by a restriction enzyme and the labeled, terminal restriction fragments (TRFs) were separated by electrophoresis and detected by laser-induced fluorescence on an automated gene sequencer. PCR parameters were optimized using an in vitro model community of known organisms. Community comparisons were made between deer fecal pellets, petroleum hydrocarbon-contaminated sands …

Go to article

A New Niche For Vibrio Logei, The Predominant Light Organ Symbiont Of Squids In The Genus Sepiola, Pat M. Fidopiastis, Sigurd Von Boletzky, Edward G. Ruby Jan 1998

A New Niche For Vibrio Logei, The Predominant Light Organ Symbiont Of Squids In The Genus Sepiola, Pat M. Fidopiastis, Sigurd Von Boletzky, Edward G. Ruby

Biological Sciences

Two genera of sepiolid squids—Euprymna, found primarily in shallow, coastal waters of Hawaii and the Western Pacific, and Sepiola, the deeper-, colder-water-dwelling Mediterranean and Atlantic squids—are known to recruit luminous bacteria into light organ symbioses. The light organ symbiont of Euprymna spp. is Vibrio fischeri, but until now, the light organ symbionts of Sepiola spp. have remained inadequately identified. We used a combination of molecular and physiological characteristics to reveal that the light organs of Sepiola affinis and Sepiola robusta contain a mixed population of Vibrio logei and V. fischeri, with V. logei comprising between …

Go to article

Impact Of Temperature Acclimation On Photosynthesis In The Toxic Red-Tide Dinoflagellate Alexandrium Fundyense (Ca28), Oscar Schofield, Joseph Grzymski, Mark A. Moline, Raffael J.M. Jovine Jan 1998

Impact Of Temperature Acclimation On Photosynthesis In The Toxic Red-Tide Dinoflagellate Alexandrium Fundyense (Ca28), Oscar Schofield, Joseph Grzymski, Mark A. Moline, Raffael J.M. Jovine

Biological Sciences

This study assessed the impact of temperature on the photosynthetic activity in the dinoflagellate Alexandrium fundyense (Ca28) for cultures grown at 75 µmol photons m–2 s–1 over a range of temperatures. Increasing light intensity under static temperatures caused a 5-fold decrease in the maximum quantum yield for photosystern II (PSII) (FvlFm) Carbon fixation rates mirrored high-light depressions in (FvlFm). Cells in the presence of streptomycin showed an 83% recovery in (FvlFm); therefore, only a minor proportion of the decline in (FvlFm)was attributable …

Go to article

Photoadaptive Response During The Development Of A Coastal Antarctic Diatom Bloom And Relationship To Water Column Stability, Mark A. Moline Jan 1998

Photoadaptive Response During The Development Of A Coastal Antarctic Diatom Bloom And Relationship To Water Column Stability, Mark A. Moline

Biological Sciences

The ratio of the xanthophyll pigments diadinoxanthin and diatoxanthin to chlorophyll a [(DD + DT): Chl a] was used as a photoadaptive index during the development of a large Antarctic diatom bloom. This index was found to track fluctuations in the incident solar irradiance and the in situ light field over a 3-order-magnitude change in the water column biomass. Depth profiles of the (DD + DT): Chl a ratio showed that the upper mixed layer, assessed by physical data, was in fact stable over the course of the month. Diel experiments conducted over the same period showed a delayed …

Go to article

Vibrational Sum Frequency Spectroscopy Of Surfactants And Phospholipids Monolayers At Liquid-Liquid Interfaces, B. L. Smiley, R. A. Walker, D. E. Gragson, T. E. Hannon, G. L. Richmond Jan 1998

Vibrational Sum Frequency Spectroscopy Of Surfactants And Phospholipids Monolayers At Liquid-Liquid Interfaces, B. L. Smiley, R. A. Walker, D. E. Gragson, T. E. Hannon, G. L. Richmond

Chemistry and Biochemistry

Work from our laboratory on vibrational sum frequency spectroscopic investigations of molecular ordering at the carbon tetrachloride-water interface is reviewed. Simple charged surfactants adsorbed at the liquid-liquid interface are seen to induce alignment of interfacial water molecules to a degree which is dependent on the induced surface potential. Saturation of water molecule alignment occurs at a surfactant surface concentration corresponding to a calculated surface potential of approximately 160 mV. In complementary studies, the relative degree of hydrocarbon chain ordering within monolayers of symmetric phosphatidylcholines of different chain lengths is inferred by the relative signal contributions of the methyl and methylene …

Go to article

The Biology Of Nonfrugivorous Tephritid Fruit Flies, David H. Headrick, Richard D. Goeden Jan 1998

The Biology Of Nonfrugivorous Tephritid Fruit Flies, David H. Headrick, Richard D. Goeden

Horticulture and Crop Science

This review is the first comprehensive treatment of the biology of nonfrugivorous fruit flies of the family Tephritidae. Feeding habits of destructive and useful species, morphology of immature stages, and hypotheses regarding structural homology and the evolutionary biology of nonfrugivorous tephritids are reviewed, including zoogeography and theories involving resource heterogeneity, guild structure, resource partitioning, resource utilization, facultative niche exploitation, extrinsic and intrinsic factors, host associations, seasonal distribution and phenology, aggregative and circumnatal life history strategies, voltinism, diapause, aestivation, oviposition site, clutch size, and supernumerary oviposition.

Go to article

Alcohol, Hormones, And Postmenopausal Women, Matthew P. Longnecker, Marilyn Tseng Jan 1998

Alcohol, Hormones, And Postmenopausal Women, Matthew P. Longnecker, Marilyn Tseng

Kinesiology and Public Health

Many women take supplemental estrogens after menopause, a practice called hormone replacement therapy (HRT). Moderate alcohol consumption may increase estrogen levels in women receiving HRT, potentially affecting their risk for various adverse health effects. Two recent studies, however, provide no strong evidence for an effect of alcohol on hormones in postmenopausal women. The possible association between alcohol consumption and risk of cancer of the breast does not appear to be mediated by estrogens. Both estrogens and moderate alcohol consumption have been associated with a decreased risk for cardiovascular disease; however, alcohol’s beneficial effect on heart disease does not appear to …

Go to article

Influence Of Ground Cover On Spider Populations In A Table Grape Vineyard, Michael J. Costello, Kent M. Daane Jan 1998

Influence Of Ground Cover On Spider Populations In A Table Grape Vineyard, Michael J. Costello, Kent M. Daane

Horticulture and Crop Science

1. Cover crops and/or resident ground vegetation have been used in California vineyards to increase the number of predators and decrease the number of pestiferous herbivores. The most common resident predators in vineyards are spiders (Araneae). Several observational studies suggest that the addition of cover crops results in an increase in spider density and a decrease in insect pest densities. 2. To test experimentally the effects of cover crops and/or resident ground vegetation (hereafter collectively referred to as ground cover) on spider populations, a 3-year study was undertaken in a commercial vineyard. Large, replicated plots were established with and without …

Go to article

Probing The Intermolecular Hydrogen Bonding Of Water Molecules At The Ccl4/Water Interface In The Presence Of Charges Soluble Surfactant, D. E. Gragson, G. L. Richmond Dec 1997

Probing The Intermolecular Hydrogen Bonding Of Water Molecules At The Ccl4/Water Interface In The Presence Of Charges Soluble Surfactant, D. E. Gragson, G. L. Richmond

Chemistry and Biochemistry

The molecular structure and hydrogen bonding of water molecules at the CCl4/water interface in the presence of a charged soluble surfactant has been explored in this study using vibrational sum frequency generation. By examining OH stretching modes that are highly sensitive to the local hydrogen bonding environment it is found that water molecules at the CCl4/water interface both in the presence and absence of a charged soluble surfactant are predominantly in a tetrahedral arrangement much like the structure ofice. Isotopic dilution studies have been employed to further characterize this icelike interfacial structure. Ablueshift ofapproximately120 cm-1 …

Go to article

Review Of Sexual Selection: Mate Choice And Courtship In Nature By James L. Gould And Carol Grant Gould, Marlene Zuk, Gita R. Kolluru, Kurt A. Mckean Dec 1997

Review Of Sexual Selection: Mate Choice And Courtship In Nature By James L. Gould And Carol Grant Gould, Marlene Zuk, Gita R. Kolluru, Kurt A. Mckean

Biological Sciences

No abstract provided.

Go to article

Sources Of Variability In The Column Photosynthetic Cross Section For Antarctic Coastal Waters, Mark A. Moline, Herve Claustre, Barbara B. Prezelin Nov 1997

Sources Of Variability In The Column Photosynthetic Cross Section For Antarctic Coastal Waters, Mark A. Moline, Herve Claustre, Barbara B. Prezelin

Biological Sciences

Using a highly resolved Long Term Ecological Research (LTER) database collected near Palmer Station, Antarctica, from 1991 to 1994, the variability in the column photosynthetic cross section (ψ*, m2 g Chl a -1) was analyzed. The relationship between the daily integrated primary production rates versus the product of surface irradiance (QPAR(0*)) and the integrated chlorophyll content (down to 0.1% QPAR(0*)) gave a ψ* value of 0.0695 m 2 g Chl a-1 (r2 = 0.85, p 2 g Chl a-1) with extreme values extending over a fiftyfold range (0.009-0.488 m 2 …

Go to article

Tree Root Response To Circling Root Barriers, Laurence R. Costello, Clyde L. Elmore, Scott J. Steinmaus Nov 1997

Tree Root Response To Circling Root Barriers, Laurence R. Costello, Clyde L. Elmore, Scott J. Steinmaus

Biological Sciences

Root system size and distribution were measured for Raywood ash (Fraxinus oxycarpa 'Raywood') and Lombardy poplar (Populus nigra 'Italica') planted with and without circling root barriers. Trees with circling barriers had fewer numbers of roots than controls (no barriers), but mean root diameters were similar. Root depth 30 cm outside barriers was greater for trees with barriers, but at 90 and 150 cm away, depth was equivalent to controls. Roots tended to grow toward the soil surface after growing under the barriers. No consistent differences in root response to any of the four types of barriers tested were …

Go to article

Liquid-Liquid Immiscibility In Lipid Monolayers, John P. Hagen, Harden M. Mcconnell Oct 1997

Liquid-Liquid Immiscibility In Lipid Monolayers, John P. Hagen, Harden M. Mcconnell

Chemistry and Biochemistry

Some binary lipid mixtures form coexisting liquid phases when spread at the air/water interface. This work describes the pressure–composition phase diagrams of binary mixtures of four unsaturated phosphatidylcholines with dihydrocholesterol. These four binary mixtures have critical compositions of approximately fifty mole percent, and average critical exponents of 0.25±0.07. The data can also be approximated by a regular solution thermodynamic model, yielding parameters for the non-ideality of these mixtures.

Go to article

Dry Weight Production And Nitrogen Efficiency Traits In Kentucky Bluegrass Cultivars In Nutrient Solution And Soil, Anthony F. Bertauski, John M. Swiader, David J. Wehner Sep 1997

Dry Weight Production And Nitrogen Efficiency Traits In Kentucky Bluegrass Cultivars In Nutrient Solution And Soil, Anthony F. Bertauski, John M. Swiader, David J. Wehner

Office of the Dean (CAFES) Scholarship

Because of the importance of such factors as appearance and vigor in turf management, genetic selection of Kentucky bluegrass (Poa pratensis L.) is often conducted at high levels of N application. This process can mask potential differences between genotypes in N efficiency, especially under low N levels. The case is also made that because soil is the medium in which plant selections ultimately must perform, cultivar screening for N efficiency in solution culture should relate to results in soil. This study was conducted to evaluate N-utilization efficiency (NUE – mg plant dry matter mg-1 plant N) in six …

Go to article

First Prev Next Last