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4921. [Article] Seasonal life history of Oncorhynchus mykiss in the South Fork John Day River Basin, Oregon
Understanding seasonal changes in growth, survival, and movement rates is crucial to salmonid management. These life history characteristics provide a context for evaluation of management actions. We evaluated ...Citation Citation
- Title:
- Seasonal life history of Oncorhynchus mykiss in the South Fork John Day River Basin, Oregon
- Author:
- Tattam, Ian A.
Understanding seasonal changes in growth, survival, and movement rates is crucial to salmonid management. These life history characteristics provide a context for evaluation of management actions. We evaluated the life history of individually marked Oncorhynchus mykiss gairdneri in the South Fork John Day River basin in Northeastern Oregon. This thesis focuses on Murderers and Black Canyon creeks, two tributaries to the South Fork John Day. These are semi-arid, mid elevation basins with naturally reproducing populations of summer steelhead and redband trout (both O. mykiss). Summer steelhead populations in this basin have declined from historic abundances, and are protected under the Endangered Species Act. In Chapter 2, we evaluate life history variation in Murderers Creek during four consecutive seasons. Growth rate varied significantly with season (F[subscript 3,88] = 62.56, P < 0.0001), with most growth occurring during spring. Location and season interacted F[subscript 6,88] = 4.45, P < 0.001) to influence individual growth rates. As a result, regions of high growth potential shifted up and down-stream seasonally. However, we found low rates of O. mykiss movement (<3%) in Murderers Creek during summer, suggesting that individuals did not track resource availability at a large scale. Apparent survival rate varied among reaches, but was consistently higher in the upstream most reach compared to the two lowermost reaches. Survival rates were similar between summer and fall, indicating that declining fall temperatures did not increase mortality. A shift in population distribution occured during fall (September through December), as some O. mykiss emigrated from tributaries into the mainstem South Fork John Day River. In Chapter 3, we investigate differences in fall life history between and within tributaries. A significantly greater proportion of O. mykiss emigrated from Murderers Creek compared to Black Canyon Creek during two consecutive years (P < 0.001 for both years). There were no significant differences in proportion of emigrants between years within either stream (P > 0.10 for both streams). In Murderers Creek, odds of emigration were related to stream reach of summer residence. Odds of fall emigration were also significantly and positively related to body length in fall and growth rate during summer. This suggests that competitive dominants volitionally emigrated from Murderers Creek during fall. After emigration, O. mykiss dispersed primarily further downstream into the Mainstem John Day River. Radio-telemetry indicated that the majority of fall emigrants occupied a < 6 km section of the Mainstem John Day River. Fall emigrants had growth rates during their winter niche shift that were significantly (P < 0.001) higher than those of individuals remaining in tributaries. This study underscores the need to monitor during all seasons to accurately characterize habitat quality. Life history patterns are an important population response to environmental change. This thesis provides an ecological context for monitoring recovery of O. mykiss populations in the South Fork John Day River basin.
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4922. [Article] The Application of Brine Injection Technology to Improve Quality of Pacific whiting (Merluccius productus) Fillets
Existing research reports the importance of brine injection technology in enhancing the quality of muscle products such as poultry, beef, and pork. In fish, the utilization of brine injection technology ...Citation Citation
- Title:
- The Application of Brine Injection Technology to Improve Quality of Pacific whiting (Merluccius productus) Fillets
- Author:
- Harikedua, Silvana Dinaintang
Existing research reports the importance of brine injection technology in enhancing the quality of muscle products such as poultry, beef, and pork. In fish, the utilization of brine injection technology is well-known for delivering marinade ingredients for salted or smoked fish production. Until now, there has been limited published scientific evidence on the incorporation of brine ingredients containing protease inhibitors to improve the quality of fresh or frozen fish fillets. Thus, the studies presented in this thesis focused on improving the quality of Pacific whiting (Merluccius productus) fillets through brine injection technology. Pacific whiting fillets are not considered desirable in the U.S. market because their meat is easily softened during slow cooking. The first study explored whether multi-needle injection technology is applicable to the improvement of Pacific whiting raw fillet quality. Color, texture, rancidity, moisture and protein were determined to understand how brine treatments affected appearance, oxidative stability and composition of the fillets. The impact of brine ingredients on myofibril protein was evaluated by gel electrophoresis. All brines were formulated with a base solution (3% sodium tripolyphosphate and 3% salt). Treatments consisted of base brine (B), base brine + 3% egg white (B[subscript EW]), and base brine + 0.1% xanthan gum+ 3% dried potato extract (B[subscript PE]). Ten fillets were injected per treatment and a 10% brine uptake was targeted for all fillets. Actual brine incorporation was 12.35 ± 2.28%. The lightness (L*) value of raw fillets indicated that B[subscript EW] and B[subscript PE] were darker than C and B (P < 0.05). Breaking strength demonstrated higher variability in non-injected samples than in injected samples. Enzyme assays showed no differences between all treatments when it was tested using buffer at pH 5.5 (P = 0.06). SDS-PAGE analysis showed minor changes in myofibril proteins between injected fillets and non-injected fillets. The second study aimed to evaluate the brine effectiveness in inhibiting protease activity in the fillet through heating. Control samples included non-injected (NI) fillets and fillets injected with water (W) only. For all other treatments, brines contained 3% (w/w) salt and sodium tripolyphosphate as a base brine (B). Additional, brine treatments with egg white were a combination of the base brine (B) with either 1, 2 or 3% egg white (B[subscript 1EW], B[subscript 2EW], B[subscript 3EW]). For potato extract, 0.1% xanthan gum was added to the base brine to aid in its suspension (BXG). Potato extract was added to B[subscript XG] at similar levels as egg white (B[subscript 1PE], B[subscript 2PE], B[subscript 3PE]). Previously frozen butterfly fillets were tempered to 2.0 ± 1.0 °C, injected with a selected treatment, vacuum packaged and immediately cooked in either one of two different heating conditions. Vacuum packed fillets were either submerged in water at 90 °C for 20 min to achieve a final internal temperature 62.8 °C (145 °F) or submerged in a 60 °C water bath for 30 min and then immediately transferred to a 90 °C water bath for 20 minutes. The pH, moisture, crude protein, total extractable protein, total non-extractable protein, texture profile analysis, and SDS-PAGE electrophoretic pattern in cooked fillets were determined. For TPA measurements, an uninjected cod sample was used as a reference sample. Compositional analysis determined the cooked NI fillet was less moist than all injected samples (P < 0.05), suggesting TPA attributes would be higher than injected samples, which was confirmed. Protein patterns from SDS-PAGE electrophoresis indicated that the myosin bands were slightly diminished when fillets were heated at 60 °C prior to cooking at 90 °C for all treatments, except in fillets containing egg white or potato extract ingredients, suggesting these treatments provided some protection to myofibrillar structure. Fillets cooked using the challenge heat treatment were significantly (P < 0.05) softer than those cooked using the sous vide for all TPA attributes. Additionally, future research considerations that would benefit the applicability of the injection process to fillet quality improvement should include determining the appropriate fish size to target for the injection process, the shelf life of injected fillets during frozen or refrigerated storage, and consumer acceptance of the injected fillets.
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4923. [Article] The Global Consumption Speeds of Premixed Large-Hydrocarbon Fuel/Air Turbulent Bunsen Flames
Large-hydrocarbon fuels are used for ground and air transportation because of their high energy-density and will be for the foreseeable future. However, combustion of large-hydrocarbon fuels in a turbulent ...Citation Citation
- Title:
- The Global Consumption Speeds of Premixed Large-Hydrocarbon Fuel/Air Turbulent Bunsen Flames
- Author:
- Fillo, Aaron Jesse
Large-hydrocarbon fuels are used for ground and air transportation because of their high energy-density and will be for the foreseeable future. However, combustion of large-hydrocarbon fuels in a turbulent environment is poorly understood and difficult to predict. The turbulent flame speed, which is the velocity at which a flame front propagates through a turbulent fuel and air mixture, is a key property in turbulent combustion. The turbulent flame speed can be used as a model input parameter for tur- bulent combustion simulations. However, turbulent flame speeds for large-hydrocarbon fuels are largely unknown. These values are needed to improve combustion models and enhance understanding of the physics and chemistry that control turbulent combustion of large-hydrocarbon fuels. The objective of this study is to measure the turbulent flame speed of large-hydrocarbon fuels and to identify key physics in the turbulent combustion of these fuels. This is motivated by the use of the turbulent flame speeds in modeling combustion in practical devices and the significant use of large-hydrocarbons in these devices. This research has broad implications for society and industry; both the Federal Aviation Administration and gas turbine engine companies have called for research on the turbulent flame speeds of large-hydrocarbon fuels. The turbulent flame speed in this work is defined as the global consumption speed, and is measured for three fuels on a turbulent Bunsen burner. The Reynolds number, turbulence intensity, preheat temperature, and equivalent ratio can be independently controlled using the burner. A conventional Jet-A fuel, known as A2, is used as a reference because of its common use in commercial and military aviation. A2 is compared to bi-modal and quadra-modal blends referred to as C1 and C5, respectively. These fuels are selected as they have similar heat releases and laminar flame speeds. Time-averaged line of site images of OH*, CH*, and CO₂* chemiluminescence are used to determine an the average flame front area. This flame area is used to determine the global consumption speed. The global consumption speed is measured for Reynolds number and equivalence ratio ranging between 5.000-10.000 and 0.7-1, respectively. Turbulence intensities are varied between 10% and 20% of the bulk flow velocity. The global consumption speed increases with turbulence intensity and Reynolds number for all fuels. Global consumption speeds for A2 and C5 match within 5% at all conditions. Conversely, the global consumption speed of C1 is up to 22% lower than A2 or C5. These results indicate the global consumption speed is sensitive to turbulent velocity fluctuations, bulk flow velocity, and fuel chemistry. These results together suggest the global consumption speed is additionally sensitive to flame stretch. Dimensional analysis is used to isolate and identify sensitivities of the global consumption speed to turbulent velocity fluctuations, bulk flow velocity, global stretch rate, and fuel chemistry. A clear sensitivity to fuel chemistry is observed and is affected by aromatic and alkane content. A2 and C5 have higher global consumptions speeds and increased stability; these fuels have shorter average hydrocarbon chain lengths and higher aro- matic content than C1. In addition, the global consumption speed is highly sensitive to turbulence intensity of the flow; the turbulent flame speed increases an average of 30% for all fuels between the minimum and maximum turbulence intensity cases. Results are attributed to a strong sensitivity of the global consumption speed to flame stretch and a strong coupling of turbulence and fuel chemistry effects. These conclusions agree with the available literature and provide a foundational understanding of the sensitivities of the global consumption speed for large-hydrocarbon fuels.
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4924. [Article] Bioactive glass filled resin composites : mechanical properties and resistance to secondary tooth decay
Dental resin composites are widely used in modern dentistry due to their aesthetic appearance. However, resin based restorations have inferior mechanical properties (fracture is the second reason for restorations ...Citation Citation
- Title:
- Bioactive glass filled resin composites : mechanical properties and resistance to secondary tooth decay
- Author:
- Khvostenko, Dmytro
Dental resin composites are widely used in modern dentistry due to their aesthetic appearance. However, resin based restorations have inferior mechanical properties (fracture is the second reason for restorations replacement) in comparison to alloy based composites and their antimicrobial properties still remain poor, leading to secondary tooth decay development on tooth-filling interface (which is the primary reason for restorations failure). In this work the Bioactive glass (BAG) was used as an antimicrobial filler. Experimental composites were prepared with 0-15 wt% BAG filler and 72-57 wt% silane treated silica glass, keeping a total filler content constant at 72 wt%. BAG composite's mechanical properties were examined, using 3-point bending beams for flexural strength measurement, pre-cracked compact-tension samples, C(T), for fracture toughness and fatigue crack growth evaluation. All mechanical properties were tested for different soaking treatments of the samples: 24 hours in DI water (all experiments) 2 months in sterile media (flexural test only) and 2 months in media with Streptococcus mutans bacteria (all experiemtns). All mechanical properties findings were compared to those ones of commercial Heliomolar composite. Main toughening mechanisms for BAG composites were evaluated post-test by SEM. The results showed that all mechanical properties for BAG composites were unaffected by increasing the filler content from 0 to 15 wt%. Moreover, all mechanical properties of BAG composites were significantly superior over Heliomolar composites. BAG composite's flexural strength properties were not affected by any of aging treatments and a slight decrease in fracture toughness and fatigue crack growth resistance was observed after 2 months soaking in media with bacteria. Main toughening mechanisms were related to BAG composite's increased filler, which resulted in more frequent crack deflection, and crack bridging at the crack tip and far away from it. In next phase of the research, a novel bioreactor and new test specimen type were developed, which allowed investigating the synergistic effect of cyclic loading and bacterial exposure on secondary tooth decay. The bioreactor was able to provide environment suitable for bacteria, similar to lab incubators. Teeth samples were machined into the disk shape (3 mm tall, 9 mm diameter), mainly consisting of dentin and the middle of sample was drilled and restored with 0 wt% BAG (0BAG) composite (2 mm deep, 5 mm diameter), introducing semi-circumferential gap between dentin and restoration of 10-30 microns. All samples were initially disinfected with 1% chloramine solution. Streptococcus mutans biofilm was grown over the samples and then they were placed in bioreactors and subjected to 1.5 Hz loading cycling at maximum load of 25% from breaking load and R=0.1 for 2 hours, followed by 4 hours resting at minimal load. The procedure was repeated for total of 2 weeks of an experiment, during which bacteria biofilm was constantly supplied with BHI media, carbon dioxide and 37oC temperature. After 2 weeks test, samples' biofilm viability was evaluated with live/dead staining kit and then, after fixing the biofilm on the samples in 4% gluteraldehyde, all samples were sectioned across the gap and stained with Gram Crysrtal Violet CAT+ dye , followed by fluorescence microscopy to reveal the depth of bacterial penetration down the gap. The depth of bacterial penetration of loaded samples was compared to one of non-loaded samples and results revealed a significantly deeper bacterial penetration for cyclically loaded samples versus non-loaded, thus, it was concluded that cyclic loading and bacterial exposure together aid secondary tooth decay propagation. In the last phase of this project the anti-microbial properties of BAG composites were evaluated. Using the same sample preparation technique and methods from the previous phase (except that now the composite was 15 wt% BAG, a.k.a 15BAG), we found out that bacterial penetration down the gap for 15BAG composite was significantly lower (almost 50% difference) in comparison to 0BAG composite, which made us confident to draw a conclusion that 15BAG composite possesses good antimicrobial properties and can be used for secondary tooth decay prevention.
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4925. [Article] Studies on the inhibition of food-borne pathogens and spoilage bacteria by lactic acid starter cultures
The ability of Streptococcus diacetilactis to inhibit a variety of food-borne pathogens and spoilage organisms in milk and broth cultures was demonstrated. Test organisms inhibited included Pseudomonas and ...Citation Citation
- Title:
- Studies on the inhibition of food-borne pathogens and spoilage bacteria by lactic acid starter cultures
- Author:
- Daly, Charles
The ability of Streptococcus diacetilactis to inhibit a variety of food-borne pathogens and spoilage organisms in milk and broth cultures was demonstrated. Test organisms inhibited included Pseudomonas and Alcaligenes species, Eschericia coli, Salmonella, Staphylococcus aureus, Clostridium perfringens and Vibrio parahaemolyticus. In general, approximately 99.0% and 99.9% inhibition was observed in milk and broth cultures, respectively. Streptococcus lactis, Streptococcus cremoris, Pediococcus cerevisiae and Lactobacillus plantarum also inhibited S. aureus in lactic broth. Possible practical applications of the observed inhibition were examined. S. diacetilactis prevented proteolysis in milk at 7. 5C by Pseudomonas fluorescens. S. aureus was inhibited greater than 99% in vanilla cream filling, ham sandwich spread, chicken gravy, soy milk and ground beef stored at 25C for 24 hr. Development of the Gram negative flora of ground beef was also inhibited greater than 99% after storage at 7.5C for 7 days. The mechanism of inhibition of S. aureus in lactic broth was examined with emphasis on the role of pH changes and acid production by S. diacetilactis. S. aureus did not grow in cell-free culture supernatants of S. diacetilactis grown in modified lactic broth (final pH 4.3 - 4.7). However, good growth was evident when the pH was adjusted towards neutrality. When the amounts of formic, acetic and lactic acids produced by S. diacetilactis were quantitatively determined and added to lactic broth, a similar pH dependent inhibition was observed. This inhibition was not as marked as that observed with cultures or cell-free supernatants of S. diacetilactis, suggesting that factors other than acid production were involved. Nutrient depletion and hydrogen peroxide did not contribute to the inhibition in this system. Enterotoxin B synthesis by S. aureus S6 and S. aureus ATCC 14458 was studied in Brain Heart Infusion broth (BHI) and N-Z Amine NAK broth (NAK). Toxin yields by S. aureus S6 were approximately 180 μg /ml and 100 μg/m1 in NAK and BHI, respectively at 30C and 150 rpm. Yields for strain 14458 were significantly lower. When the initial inoculum of S. aureus S6 was 4 x 10⁵ cells/ml, the addition of 0.5% glucose or 0.5% maltose initially repressed both toxin synthesis and the pH rise associated with toxin synthesis; however, after 72 hr of incubation, the pH rise and toxin produced were the same as occurred without added carbohydrate. Furthermore, addition of maltose, but not glucose, reduced the toxin yield of S. aureus ATCC 14458 by about 80% at 72 hr. When S. diacetilactis (initial inoculum 1 x 10⁷ cells/ml) was added to BHI containing 0. 5% glucose or 0. 5% maltose, no toxin synthesis or pH rise was observed when the initial inoculum of S. aureus was 4 x 10⁵ cells/ml. In plain BHI, no toxin was observed under these associative growth conditions and the pH remained constant at 6.6. Inhibition of toxin production in this system could be partially reversed by the addition of 0. 5% sodium pyruvate, sodium acetate or sodium succinate. When the initial inoculum of S. aureus was 4 x 10⁸ cells/ml, only partial or no inhibition of toxin production in the presence of S. diacetilactis (inoc ulum 1 x 10⁷ c ell s /m1) was observed. Substantial inhibition by S. diacetilactis was observed at this concentration when the medium was BHI + 0. 5% maltose but not when BHI + 0. 5% glucose was used. Inhibition of toxin production but not growth was evident in NAK + 1% glucose. Sodium citrate addition inhibited both growth and toxin production by S. aureus S6. The toxin yields of the S. aureus strains were greatly reduced when static incubation was used. Inhibition by S. diacetilactis was readily demonstrated under these conditions. Three commercially available starter cultures, Lactacel, Lactacel MC and Lactacel DS, were examined for their ability to control the growth of S. aureus during a simulated beaker sausage fermentation at 21C, 30C and 37C. Although differences between cultures were evident, all three gave greater than 99% inhibition after 50 hr of incubation at 30C and 37C. Inhibition was somewhat reduced (average of 97% at 50 hr) at 21C. Chemical acidulation with gluconodelta- lactone (0.75%) plus citric acid (0. 1 %) yielded good initial control in a similar process. However, on extended incubation up to 50 hr good growth of the pathogen occurred and the inhibition was only slight or none at this time for samples incubated at 30C and 37C; at 21C inhibition was approximately 97%. A combination of starter cultures and chemical acidulation gave approximately 99.99% inhibition of S. aureus at the three temperatures after 50 hr of incubation. Possible applications of these findings to the food industry are discussed. A greater role for the lactic acid bacteria in the area of food-safety is suggested.
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4926. [Article] Transmission variation and loss of aphid transmissibility of bean yellow mosaic virus
Several bean yellow mosaic virus (BYMV) strains, presumably not transmissible by aphids, were studied to determine the biological and environmental conditions which would possibly result in aphid transmission ...Citation Citation
- Title:
- Transmission variation and loss of aphid transmissibility of bean yellow mosaic virus
- Author:
- Kamm, James A.
Several bean yellow mosaic virus (BYMV) strains, presumably not transmissible by aphids, were studied to determine the biological and environmental conditions which would possibly result in aphid transmission of these strains. Investigations were made to study the effect of different aphid rearing conditions on the transmission frequency of BYMV. Also, the probing behavior of Myzus persicae (Sulzer) was studied in relation to transmission frequency of BYMV to test plants. Differences other than loss of transmissibility were found to account for the failure of aphids to transmit some BYMV strains. Five strains varied in ability to infect specific pea and bean varieties; all strains were aphid transmissible except BYMV III. BYMV I and II no longer produced systemic infection in Perfected Wales pea or Dwarf Horticultural bean although both strains produced local infection in inoculated leaves of Perfected Wales pea. Only BYMV y21 and III produced systemic infection in Dwarf Horticultural bean. The above changes in virus infectivity were attributed to virus mutation. Both Dwarf Horticultural bean and Perfected Wales pea are commonly used as differential hosts to identify legume viruses. BYMV and pea mosaic virus are distinguished only on the inability of pea mosaic virus to infect bean. Consequently, the validity of virus classification of legume viruses based on differential host reaction is questionable. In addition to the above variation, BYMV I and II required a high post-inoculation temperature to produce infection in Blue Lake bean; other strains were not affected under the same conditions. The host range of BYMV I, II, III, and IV was the same in the plants: Trifolium pretense L., Crotolaria spectabilis Roth., Trifolium subterranean L. variety Yarloop, Chenopodium amaranticolor Coste and Reyn., Glycine max (L.) Merr. variety Lincoln, Melilotus alba Desr., and Pisumm sativum L. variety Lincoln. BYMV III, maintained by mechanical transfer since 1963, was not transmitted to ten plant species in attempts with over 5000 aphids. Myzus persicae (Sulzer) failed to transmit BYMV III from five different species or varieties of source plants. This was interpreted as evidence that virus acquisition by aphids, due to the source plant, was not involved in loss of aphid transmissibility of BYMV III. Five aphid species and ten test plant species were used in an attempt to find a vector-host plant combination which would result in aphid transmission of BYMV III. Macrosiphm albifrons Essig and Acyrthosiphon pisum (Harris) finally transmitted BYMV III to Crotolaria spectabilis Roth. This was the first transmission of BYMV III after attempts with more than 5000 aphids. The return of aphid transmissibility in BYMV III could be explained only on the basis of virus mutation. Indirect evidence from two experiments suggested that aphid transmissible and non-transmissible forms of BYMV III were present in the stock culture when Macrosiphum albifrons first transmitted BYMV III. Aphids transmitted the isolate first transmitted by Macrosiphum albifrons at a higher frequency than the stock culture of BYMV III. A subsequent experiment indicated that almost any aphid would transmit BYMV III after return of aphid transmissibility. Transmission of BYMV IV by aphids reared on Chinese cabbage was compared to that of aphids reared on a chemically defined diet. The trend in frequency of transmission implied that aphids reared on the artificial diet were inferior in transmission of BYMV IV. The probing behavior of Myzus persicae on Pisum sativum and Phaseolus vulgaris was evaluated in relation to the transmission frequency of BYMV. Plant susceptibility of pea and bean was the same. Aphids made 40 percent more probes on bean than on pea in a 15 minute observation period. However, increased transmission to bean was not reflected by the greater number of probes. There was no evidence that transmission of BYMV was affected by observed differences in the probing behavior of Myzus persicae.
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Zonotrichia leucophrys gambelii is a strongly migratory race of white-crowned sparrow that exhibits a marked deposition of fat during the vernal migratory period. The physiological basis for fat deposition ...
Citation Citation
- Title:
- An investigation of the feeding pattern of caged white-crowned sparrows, Zonotrichia leucophrys gambelli (Nuttall), in relationship to vernal fat deposition
- Author:
- Moldenhauer, Ralph Roy
Zonotrichia leucophrys gambelii is a strongly migratory race of white-crowned sparrow that exhibits a marked deposition of fat during the vernal migratory period. The physiological basis for fat deposition is a positive energy balance which results from a photo-periodically induced hyperphagia. Simultaneously with the increased caloric intake there is an adjustment of the intermediary metabolism so that the excess calories are deposited as fat rather than glycogen. The possible mechanism by which the intermediary metabolism is altered was the subject of this investigation. It was surmised that a photoperiodically stimulated change in the feeding pattern, along with hyperphagia, might induce the metabolic alterations necessary for lipogenesis and fat deposition. This idea was prompted by investigations with force-fed rats and rats limited to a two-hour feeding period per day. Ten immature Z. 1. gambelii were confined individually to small breeding cages modified to measure perch and feeding activity. The feeding activity was recorded by means of a mechanically operated feeder which electrically activated a pen on an Esterline-Angus recorder whenever the bird placed its head in the feeder to obtain food. The motor activity was registered similarly with each movement of a perch-activated microswitch. Recordings of the feeding and perch activity were made continuously throughout the premigratory and migratory periods of March, April and May. During the experimental period the birds were weighed at least twice a week with observations of molt being recorded. Prenuptial molt, fat deposition and Zugunruhe occurred essentially at the same time and magnitude as previously reported for caged and wild white-crowned sparrows. The median date for the onset of fat deposition was determined as April 11 ± 1 day. With fat deposition the mean body weight of six birds increased from 26.5 grams to 34.3 grams in 13 days. Prenuptial molt occurred at maximum intensity during the first ten days of April. The median date for the onset of Zugunruhe was determined as April 17. The mean daily feeding and perch activity of six birds were determined for five one-week periods chosen in relationship to fat deposition. The feeding activity was analyzed by the frequency, the number of feeding periods in each half-hour per bird per day, and by the duration, the total number of minutes spent at the feeder in each half-hour per bird per day. The perch activity was presented as the number of activity units per half-hour per bird per day. The results indicated a general feeding pattern with two phases: a morning phase characterized by numerous trips to the feeder of short duration interrupted by the high motor activity of the bird, and an afternoon phase distinguished from the morning phase by low perch activity and relatively less frequent feeding periods of longer duration. The feeding day was initiated almost invariably at the beginning of the morning civil twilight. The termination of the feeding day, before and after hyperphagia, was relatively constant and somewhat independent of the increasing evening photoperiod. During hyperphagia the last feeding period occurred gradually later for each succeeding day. Hyperphagia was evident in the feeding patterns of the weeks before and during fat deposition. For the week prior to fat deposition, the duration increased to 3.8 minutes/half-hour/bird/day and 112 minutes/bird/day from 3.6 minutes/half-hour/bird/day and 97 minutes/bird/day of the preceding week. The duration during the week of fat deposition increased to 4.7 minutes/half-hour/bird/day and 142 minutes/bird/day. The frequency showed similar results. The mean environmental temperature increased for each week. During hyperphagia no change in the over-all feeding pattern was indicated from those of other weeks. Under the conditions of this investigation, it was concluded that there appears to be no change in the food intake pattern of Z. 1, gambelii which can be construed as a mechanism for inducing metabolic alterations necessary for vernal fat deposition.
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Moisture content management is a key requirement to improve forest harvest residue economics for bioenergy production. This dissertation aims to contribute towards better management through these three ...
Citation Citation
- Title:
- Forest Harvest Residue Moisture Management in the Pacific Northwest, USA
- Author:
- Belart Lengerich, Maria Francisca
Moisture content management is a key requirement to improve forest harvest residue economics for bioenergy production. This dissertation aims to contribute towards better management through these three general objectives (1) Determine average moisture content of fresh forest harvest residues and its changes over the different seasons of the year, focusing on the three main commercial forest species growing in the Pacific Northwest, (2) Determine in-forest stored drying rates of this material for two harvest systems and the same species specified in objective (1) and (3) Determine the cost effectiveness of in-forest drying for two harvest systems and the advantages of drier material when its energy content is considered at a cogeneration facility. A repeated measures experimental design was conducted to determine average branch moisture content in live trees during each season of the year in four different locations in Oregon. At the same time, an innovative sampling protocol was employed to determine moisture content for in-forest stored of piled and scattered harvest residues for one year in four different Oregon sites. These data were used to calibrate finite element analysis (FEA) models to predict residue drying rates based on weather information such as temperature, relative humidity, precipitation and wind velocity. Finally, one of the FEA models was used to determine drying rates on real Douglas-fir units harvested with different harvest systems (a case study). These harvest units were employed to set a mixed integer linear program to optimally deliver harvest residues to a hypothetical cogeneration plant over 24 periods (months) and determine processing and transport costs. Major findings indicate that from all sites, the highest moisture recorded was 50% (wet basis) in ponderosa pine during the winter; the lowest was 43% in the summer for both the same ponderosa pine and Willamette Valley Douglas-fir. When compared by season, ponderosa pine had significantly higher moisture content in the winter than in other seasons (1.6 to 9.8% higher). Summer moisture content was also significantly lower than fall moisture content for ponderosa pine (5.4 to 2.5% lower). Willamette Valley Douglas-fir had significantly lower moisture content during summer than during other seasons (0.8 to 3.9% lower). FEA models were successfully developed to determine drying rates for four different climate regions in Oregon. These models were compared with data obtained in the field and statistical tests show model agreement with correlations between 0.56 and 0.92 (Kendall’s tau) on all sites. The harvest residue generated from the case study was sufficient to optimally deliver the necessary volume to supply 63% of a hypothetical 6 MW-hr cogeneration plant. Approximately 98% of the harvest residue generated with cable logging system was delivered to the plant compared with only 56% of the residue generated with a ground-based system. By considering the energy content of drier residues, the amount of ODMT needed to supply the plant can be reduced by 13.3% without affecting the energy output over a 6-period planning horizon. A lower ODMT demand and shifting to drier material results in 16.5% lower cost, which represents a more accurate estimate of the production cost. We conclude that forest harvest residues that are mainly composed of branches should not have moisture content levels greater than 50%. Seasonality should not affect the average moisture content of this material unless it is composed of ponderosa pine. After harvesting, piling residues in a berm (windrow) shape will promote drying in the summer and re-wetting in the winter. It is best to reduce pile size to facilitate drying in summer, and increase pile size if material will be left in the field over the winter. Drying times can be reduced up to 1/3 if the material is cut and left to dry during the dry, warm summer months versus starting in the winter. I this case study, residues coming from cable harvest units present a cost advantage compared to ground-based harvest units. Collection cost from the drier ground-based units was too large to offset the higher moisture content of piled residue in the cable harvest units. Recognizing the energy value of drier material has potential to improve the supply and cost estimates of the utilization of forest harvest residues for power generation.
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4929. [Article] A cooperative effort to track Humboldt squid invasions in Oregon
Interannual variability of Humboldt squid (Dosidicus gigas) occurrence in the northern California Current System is largely unknown. In Oregon, the distribution of this versatile predator and what is influencing ...Citation Citation
- Title:
- A cooperative effort to track Humboldt squid invasions in Oregon
- Author:
- Chesney, Tanya A.
Interannual variability of Humboldt squid (Dosidicus gigas) occurrence in the northern California Current System is largely unknown. In Oregon, the distribution of this versatile predator and what is influencing their range expansion from Mexico is poorly understood due to the recent nature of their "invasion" and a lack of monitoring. Humboldt squid are large predators that have the potential to affect ecosystem structure and fisheries because of their high-energy demands and ability to exploit a variety of oceanographic conditions and prey sources. Developing baseline distribution information is a critical first step to assess their potential ecological, social, and economic impacts, and to develop models to predict future range expansion. This study has two main objectives: (1) to document where and when Humboldt squid have been present in Oregon through cooperative fisheries research, and (2) to correlate the sightings with oceanographic conditions using a geographic information system (GIS) and species distribution modeling (SDM). I conducted 54 interviews with local fishermen and aggregated their squid sightings with available fishery-independent survey and fishery-dependent observer data from the National Marine Fisheries Service. I compiled a total of 339 Humboldt squid sightings, reported for the years 2002-2011 from the Oregon coast to 131° west longitude. Correlation analyses were performed for Humboldt squid sightings and sea surface temperature (SST), chlorophyll a content (chla), sea surface height anomalies (SSH), dissolved oxygen at 30 m depth (30 m DO), and sea surface salinity (SSS) using a GIS, nonparametric multiplicative regression (NPMR) habitat modeling, and maximum entropy modeling (Maxent). Results indicate that oceanographic conditions have the potential to influence Humboldt squid occurrence, and in Oregon, sightings vary temporally and spatially. Combining the sightings from fishermen and scientific surveys greatly enhanced the spatial extent of the data. Humboldt squid were most frequently observed between 124.4°W and 125°W in proximity to the shelf-break at the 200 m isobath, with peak sightings (116) recorded in 2009 and the fewest (6) reported in 2003 and 2011. The highest occurrence of Humboldt squid were observed at a SST of 10.5-13.0°C, 0.26-3.0 mg m⁻³ chla content, -4.0-1.0 m SSH anomalies, 32.2-32.8 psu SSS, and at 3-4.5 ml L⁻¹ and 6-7 ml L⁻¹ 30 m depth DO. Maps of estimated likelihood of occurrence generated by NPMR were consistent with overlayed observations from fishermen, which were not used in the model because they were limited to presence-only information. An interdisciplinary approach that incorporates cooperative fisheries research and ecosystem-based management is necessary for monitoring Humboldt squid in Oregon. Traditional methods are insufficient because Humboldt squid are data-poor, highly migratory, and are main predators of many commercially important fisheries in Oregon. Based on my findings, sightings recorded by fishermen covered a much larger area over a longer time frame than the scientific survey and observer data, and excluding their knowledge would have led to a different interpretation of Humboldt squid distribution and environmental tolerances. Although there is uncertainty in the data from potential map bias or misidentification of smaller Humboldt squid, incorporating sightings from fishermen with traditional fisheries research increases the quantity and quality of information. Cooperative monitoring for Humboldt squid could include training in species identification and sea condition reporting in logbooks. Future "invasions" are likely, and more eyes on the water will improve our understanding of the behavior and impacts of Humboldt squid on coastal resources.
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4930. [Article] A new model for the formation of Crater Lake Caldera, Oregon
During the Pleistocene, an andesitic volcano named Mount Mazama grew to a probable elevation of 3000 meters in south- central Oregon. Near the end of the Pleistocene, three diverse magma types appeared ...Citation Citation
- Title:
- A new model for the formation of Crater Lake Caldera, Oregon
- Author:
- Lidstrom, John Walter
During the Pleistocene, an andesitic volcano named Mount Mazama grew to a probable elevation of 3000 meters in south- central Oregon. Near the end of the Pleistocene, three diverse magma types appeared in the eruptive products associated with Mount Mazama: l)High-alumina basaltic andesite magma associated with an early plateau and with coeval cinder cones; 2) Hypersthene andesite magma similar in composition to the andesite which had formed the main cone; 3) Dacite magma, erupted both as pyroclastic material and as flank lava flows after formation of the andesitic cone. Approximately 12, 000-13, 000 years ago, eruption of andesite and then dacite occurred along a semicircular fracture now represented by the north wall of the caldera. The eruption of dacite was a surface expression of a shallow chamber of dacite magma emplaced beneath Mount Mazama. Before and after emplacement of the dacite magma chamber, basaltic andesite erupted upon the lower flanks and plateau surrounding the volcano, The last such parasitic activity occurred at Forgotten Crater (on the western flank of Mount Mazama) where lava and pumice of intimately mixed dacite and basaltic andesite appeared. Approximately 6600 years ago, explosive eruption of dacite pumice began from central vents. The magma of these initial eruptions was characterized by discrete gas nuclei which expanded rapidly, disrupted the enclosing liquid into fine ash, and provided the energy to propel this ash high above the summit. As eruption proceeded, magma was tapped in which gas nuclei were actively forming and were thoroughly dispersed through the magma. At this stage, the erupted material behaved as a fluidized mass, frothed over the crater rim, and rushed down the slopes as glowing avalanches. Immediately following eruption of fluidized dacite, a more mafic magma was erupted in the form of basic scoria flows. This basic scoria was chemically, similar to par3sitic eruptions of basaltic andesite, and was not nearly as mobile as the earlier dacite ash-flows. The waning stages of eruption were characterized by crystal-rich basic scoria containing abundant fragments of andesite and granodiorite. Following the eruption of crystal- and lithic-rich basic scoria, the summit of Mount Mazama collapsed into the underlying magma chamber, producing the Crater Lake caldera. Soon after collapse, eruption of mafic magma occurred on the caldera floor, probably forming a lava lake. The last eruption formed an intra-caldera andesitic cone called Wizard Island Wizard Island lavas are chemically similar to the andesites which formed the main cone of Mount Mazama. Thus, a sequence of volcanic activity culminating in violent eruption and collapse, returned to its initial condition. Calculations of Mazama ash volume are presented and it is concluded that there is no discrepancy between volume of missing Mount Mazama and volume of erupted material. Crystal-rich basic scoria flows containing melted granitic fragments (torn from the margins of the dacite magma chamber) indicate that the chamber was essentially emptied during the culminating eruptions. It is suggested that basic scoria magma occupied the bottom portion of the dacite magma chamber. This mafic magma assimilated granodiorite which had crystallized around the margins of the dacite magma. A new model for the formation of the Crater Lake caldera is presented. In this model the magma types recognized at Crater Lake ascended through the crust as independent bodies. Whenever two of these magma types came into marginal contact, limited eruption of mixed magmas was possible. However, prior to the culminating eruptions, a high-temperatures basaltic andesite magma was injected into the lower portion of the volatile-saturated, cooling dacite magma. Energy transferred from the mafic magma triggered exsolution of gas in the silicic magma until vapor pressure exceeded confining pressure. Once eruption began, it did not stop until the chamber was depleted of its gas-rich magma. The Crater Lake caldera was formed when the unsupported summit of Mount Mazama collapsed into this sub-volcanic vacancy. Many other calderas, long recognized as a special (Krakatoan) type, were produced following the eruption of more than one magma. It is suggested that the process described above is an important caldera-forming mechanism.