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Landscape history, dispersal, and the genetic structure of amphibian populationsMeyer, Shavonne. January 2007 (has links)
No description available.
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La présence et la distribution des coulées argileuses dans la vallée de la rivière Maskinongé : aspects topographiques, stratigraphiques et géotechniquesLajoie, Ginette. January 1978 (has links)
No description available.
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A qualitative study of commitment in the workplace during a period of radical changeSchmuttermaier, John R. (John Richard), 1958- January 2002 (has links)
Abstract not available
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Residue management and yield characteristics of fine fescue seed cropsSchumacher, Derek David 29 April 2005 (has links)
Chewings fescue [Festuca rubra L. subsp. fallax (Thuill.) Nyman] is a desired
turfgrass with dense sod forming capabilities and superior shade tolerance. Thermal
residue management (open-field burning) has traditionally been used to remove post-harvest
residue and maintain seed yield over the life of the stand. However, alternative
non-thermal residue management practices have been observed to produce adequate
seed yields dependent upon cultivar.
Strong creeping red fescue (F. rubra L. subsp. rubra) is desired for
its prolific tillering capacity and creeping rhizomatous growth habit. In contrast to
Chewings fescue, maintenance of seed yield in strong creeping red fescue has only
been profitably produced under thermal residue management. Slender creeping red
fescue [F. rubra L. var. littoralis (Vasey)] is a desired turfgrass with a compact, less
rhizomatous growth habit, similar to Chewings fescue in desirable turf attributes.
However, little is known about the effects of post-harvest residue management in
slender creeping red fescue.
The objectives of this study were: 1) to evaluate seed yield and yield
components among different cultivars to thermal (open-burning), and non-thermal
(flail low and flail high) post-harvest residue management; 2) to evaluate harvest
index and percent cleanout to thermal and non-thermal residue management in
different cultivars; and 3) and to provide an economic analysis of thermal and non-thermal
residue management in all cultivars based on partial budgeting.
Three post-harvest residue management treatments (burn, flail low and flail
high) were applied over the course of two years. Seed yield components measured
included: total dry weight, fertile tiller number, spikelets per panicle, florets per
spikelet, and panicle length. Final seed yield in each cultivar and residue management
treatment method was determined after seed harvest and conditioning. Seed yield
component analysis was conducted over three production seasons.
Chewings fescue, strong creeping red fescue, and slender creeping red fescue
cultivars responded differently to residue management as indicated by a residue
management by cultivar interaction. In 2003 and 2004, residue management by
cultivar interactions were evident in seed number, seed weight, fertile tiller number,
percent cleanout, harvest index, and seed yield. Residue management by cultivar
interactions occurred in spikelets per panicle in 2003, whereas in 2004 a residue
management by cultivar interaction occurred in panicle length and florets per spikelet.
In 2004, non-thermal flail low, and thermal residue management resulted in
significantly greater spikelets per panicle in all cultivars. Thermal residue management
resulted in the greatest number of spikelets per panicle.
Results indicate that thermal residue management best maintained seed yield in
most subspecies and cultivars across both years. However, in 2003, non-thermal flail
low residue management produced profitable seed yield in only Marker slender
creeping red fescue. In contrast, thermal residue management resulted in poor seed
yields in Marker slender creeping red fescue and enhanced yields in Seabreeze slender
creeping red fescue in 2003. However, following the second year of thermal treatment
in 2004, Marker and Seabreeze both had lower seed yields, thus exhibiting the only
negative impact of thermal management among the cultivars tested in this study.
Moreover, upon review of an economic analysis, Marker slender red fescue was the
only cultivar that produced a positive net return of $78 and $4 ha⁻¹ under non-thermal
residue management in 2003 and 2004, respectively. Furthermore, in 2003, thermal
residue management net return increases ranged from $104 ha⁻¹ to -$996 ha⁻¹ in
Barnica and Shademark, respectively. In 2004, thermal residue management net return
increases ranged from $115 ha⁻¹ and $1,332 ha⁻¹ in Seabreeze and Shademark,
respectively.
Poor seed yields were observed in all strong creeping red fescue cultivars
under non-thermal residue management across both years of the study. This may be
attributed to an observed reduction in fertile tiller number and seed yield. In addition,
percent seed cleanout was increased with non-thermal residue management. In 2004,
as stand age increased, thermal residue management resulted in greater seed yields in
all cultivars and species, except both cultivars of slender creeping red fescue. Thus,
this study provided substantial evidence that thermal residue management has the
potential to maintain or increase fine fescue seed yield as stands age as well as to
maintain stand profitability. / Graduation date: 2005
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Fish assemblage organization in the Amazon River floodplain : species richness, spatial distribution and recruitment processesPetry, Paulo 25 May 2000 (has links)
The composition and distribution of fish assemblages was examined in a
floodplain lake system in the Amazon basin. Quantitative samples were
collected during the 1992-1993 flooding season at Marchantaria Island, Solimoes
River. A total of 25,819 specimens representing 8 orders, 30 families, 101
genera and 139 species of fish were collected. Analysis of species richness
distribution among 7 vegetation strata showed that vegetated sites had higher
species richness than unvegetated sites. Stands of Paspalum repens had the
most diverse fish fauna. Canonical correspondence analysis (CCA) was used to
investigate relationship between fish assemblages and 16 environmental
variables. CCA revealed that dissolved oxygen, water transparency, water depth
and aquatic vegetation structure were significantly related to fish assemblage
organization. The results suggest that physiological adaptations to hypoxia and
habitat complexity play a major role in the organization of these assemblages.
The morphology, ontogenetic development, shape variability and deposition of
otolith microincrements are described for floodplain serrasalmin fishes.
Serrasalmin otoliths were similar to other ostariophysan, nevertheless their
shape was species-specific. Elliptical Fourier analysis showed that Mylossoma
aureum lapilli were highly variable in shape when compared to closely related
species. PCA and discriminant function analysis indicated that two distinct forms
of lapillus can be recognized for M. aureum, and intra-species variation was
higher than inter-species variation. Otolith microincrement analysis was tested
for these fishes, and microincrement deposition validation showed that Piaractus
brachipomus deposits otolith increments on a daily basis. Patterns of spatial
distribution, growth and mortality characteristics of larvae and juvenile were
examined for M. aureum inhabiting the Marchantaria Island floodplain. Otolith-derived
birth date reconstruction showed that M. aureum spawning season
extended from late November to March, and peak larvae recruitment to the island
occurred in mid-December. Larvae and juveniles had different spatial
distributions in relation to habitat usage. Instantaneous growth coefficients (g)
varied from 0.0197(d�����) to 0.265(d�����) among cohorts. Early-season cohorts had
wider otolith microincrements and higher instantaneous growth coefficients than
late-season cohorts. Mortality estimated by the decline of loge (abundance)
regressed on age indicated that cohort-specific instantaneous mortality varied
significantly among cohorts, ranging from 0.027(d�����) (2.6%/d) to 0.103(d�����)
(9.7%/d). / Graduation date: 2001
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Assessment of impacts of Canada geese on wheat productionLouhaichi, Mounir 22 January 1999 (has links)
Numbers of wild Canada geese (Branta canadensis) have increased dramatically during the past 30 years in the lower Columbia and Willamette Valley systems. The damage they cause by grazing and trampling plants can be substantial.
The objectives of this research were to:
1) Develop methods that provide reliable estimates of goose impact on wheat yield and quality, and 2) Develop methods to separate goose damage from other factors that lower
yield such as poor soil or waterlogging.
To document grazing impacts, color aerial photography was combined with Global Positioning System (GPS) and precision farming technology. Field-scale color aerial photographs (1:14,000 scale) were acquired four times during each growing season: in January, March, April, and just prior to harvest in July. Each flight was coupled with ground truth data collection to verify exact cause of spectral signature variation or variations in wheat cover. Such data included wheat height, number of goose droppings, and a relative rating of goose grazing intensity. At each sampling point a platform photograph and a GPS location were taken.
Wheat yield impact varied considerably as field size, shape and proximity to road varied. Yield maps revealed that, goose grazing had reduced grain yield by 25% or more in heavily grazed areas. At harvest time during the first year, wheat grain in the heavily grazed areas had higher moisture content due to delayed maturity. Therefore those areas were harvested two weeks later. Heavily grazed areas also had more weeds than ungrazed portions of the field. Late-season (April) grazing was more damaging to wheat yield than was earlier season grazing, but early season grazing did have an impact on yield. Intensely hazed fields had lower levels of damage than did fields or portions of fields that were not as vigorously guarded.
Our results illustrate very practical ways to combine image analysis capability, spectral observations, global positioning systems, precision farming and ground truth data collection to map and quantify field condition or crop damage from depredation, standing water, or other adversities. Image analysis of geopositioned color platform photographs can be used to stratify winter wheat fields into impact units according to grazing intensity. Ground-truth data, when collected in conjunction with a GPS, provided the information needed to locate and establish the spectral properties of impacted areas. Once the spectral properties of a representative area were identified, information could be extrapolated to other areas with the same characteristics. In addition, this method could be used in conjunction with aerial photography to verify areas of grazing. The combination of two or more of these tools would provide farm managers and agricultural consultants with a cost-effective method to identify problem areas associated with vegetation stress due to heavy grazing by geese or other factors. / Graduation date: 1999
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Lower and Middle Devonian carbonate-platform and outer-shelf-basin deposits flanking Railroad Valley, NevadaNelson, Storr L. 21 May 1996 (has links)
Lower and Middle Devonian strata crop out on the former
stable carbonate platform that existed in the Quinn Canyon Range,
through the carbonate shelf edge in the Pancake Range, to the
carbonate slope and outer-shelf basin in the Reveille Range.
The strata of the Reveille Range record a transition from
deposition on the carbonate platform in the Lower Devonian, to
deposition at the carbonate platform margin, to deposition in the
outer-shelf basin in the Middle Devonian. Conodonts collected from
the base of the Sevy Dolomite yield a kindlei-Zone age, an indication
that the Sevy Dolomite is younger than previously recognized.
Throughout the Lower and Middle Devonian, carbonate strata
of the Pancake Range and Quinn Canyon Range were deposited on the
shallow carbonate platform. Conodonts collected from the base of the
Lower Alternating Member of the Simonson Dolomite in the Quinn
Canyon Range have a slightly older age (serotinus- to costatus Zone)
than other eastern Nevada locations.
The Lower Devonian Sevy Dolomite was deposited in a shallow
carbonate subtidal through supratidal environment and is similar in
outcrop throughout the ranges. Petrographic studies show that the
samples are lithologically and diagenetically similar, indicating a
similar intensity of dolomitization from the precursor calcareous
mudstone. The Formation classifies as bioturbated mudstone and
wackestone.
The Middle Devonian Simonson Dolomite was deposited in
shallow carbonate subtidal through supratidal environments. The
Simonson Dolomite was affected by Milankovitch Cycles, glacioeustatic
oscillations of sea level, producing a characteristic rhythmic
bedding.
The Middle Devonian Sadler Ranch Formation and Denay
Limestone are lithologically and diagenetically different from the
shallow water deposits of the Lone Mountain Dolomite, Sevy
Dolomite, and Simonson Dolomite. The Sadler Ranch Formation and
Denay Limestone were deposited at the carbonate platform edge and
on the carbonate slope and outer-shelf basin, respectively. The
Sadler Ranch Formation is dolomitized and may be classified as
fossiliferous wackestone and mudstone. The Denay Limestone is not
dolomitized and is classified as mudstone and fossiliferous grainstone
and packstone.
Dolomitization in the Paleozoic strata of Nevada is a secondary
feature, an early diagenetic replacement of strata which were
originally limestone. This replacement process was controlled by
transgressions and regressions of the shoreline. Shallow carbonate
platform deposits (shelfal and tidal-flat) are dolomitized, whereas
deep water outer-shelf basin and slope deposits are not. / Graduation date: 1997
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On the edge of empires : the Hisor valley of TajikistanRowe, William Campbell 10 December 2012 (has links)
Not available
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Liming requirement of selected Willamette Valley soilsPeterson, Paul William 01 September 1971 (has links)
There are two major problems associated with soil acidity and
lime response investigations:
A. Determining how much lime (100% "available" CaCO��� equivalent)
is required to raise a soil pH (or degree of acidity) from its
existing level to a specified level - presumably where need for
lime is eliminated.
B. Determining responses of different crops on different soils to
lime; and defining some chemical measurement of the soil that
will predict the response of a specified crop.
Investigations in this study were limited to the first problem.
Liming characteristics of 45 acid Willamette Valley soils, representing
the major agricultural soil associations, were determined by incubating
the soils with increments of CaCO���. The lime required to
bring the soils to the specified pH levels of 6.8, 6.4 and 6.0 varied
widely within the respective pH levels. Relationships between soils,
however, as determined by the value of the incubation curve slope
(meq. of CaCO��� /100g of soil required to raise soil pH by one unit),
were improved by grouping into related soils. Laboratory measurements
of other soil chemistry parameters were compared with
changes in pH to determine if a satisfactory quick laboratory procedure
could be developed to measure the incubation lime requirement
of soils with different chemical characteristics.
Measurements of soil pH were made by three different methods:
(1) in the supernatant of a 1:2 soil to water suspension; (2) in the
sedimented paste of the 1:2 soil to water suspension; and (3) in the
supernatant of a 1:2 soil to 1 N KCl suspension. Lime requirement
with a buffered solution was measured in limed and unlimed
soils by use of the SMP (Shoemaker, McLean, and Pratt) buffer
method. Soil samples treated with increments of lime were analyzed
for extractable Al and exchange acidity by titration and the unincubated
soils were analyzed for exchange acidity determined by subtracting
exchangeable bases from CEC measured at pH 7. 0 and pH 6. 0.
Results of the correlation analyses showed that the SMP buffer
method should prove useful for predicting the incubation lime requirement.
Correlation coefficients for these two values were .89, .90
and 86, respectively, to reach pH levels of 6.8, 6.4 and 6.0. Soil
pH measurements, extractable Al, and exchange acidity determinations
did not provide as good a basis for determining incubation lime requirements,
Regression equations were calculated for the SMP
buffer/incubation lime requirement relationships.
The purpose of this study was to identify the changes in soil
chemical measurements that take place with application of lime. No
attempt was made to determine whether a crop might respond to an
application of lime on an acid soil. The assumption was made that
yield could be related to specific pH or soil acidity levels that could
be measured in the laboratory. Therefore, the problem was approached
by studying procedures that might determine the application of lime
required to reach a specified pH or soil acidity measurement. It
anticipated that field trials for evaluating lime response will be
carried out in the future to evaluate the usefulness of the SMP buffer
method which showed promise in this regard. / Graduation date: 1972
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The acculturation of the French Huguenots in the British colonies with special reference to the Oley Valley in Berks County, Pennsylvania /McCormick, Linell. January 1984 (has links)
Thesis (M.A.)--Kutztown University. / Typescript. Source: Masters Abstracts International, Volume: 45-06, page: 2914. Includes bibliographical references (leaves 130-134).
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