1,120 research outputs found
Enhancing the yield of target tissue and secondary metabolites in Calendula officinalis L., a medicinal plant.
Medicinal crops can be usefully studied in controlled hydroponic systems in which various factors can be manipulated to increase target plant tissue yield and secondary metabolite production. In this project floral tissue and other plant organs of the medicinal plant Calendula officinalis and four important secondary metabolites: quercetin, rutin, isorhamnetin-3-O-glucoside and isorhamnetin-3-rutinoside were quantified under contrasting conditions in terms of phosphorus concentration, rate of nutrient supply and simulated foliar herbivory in a factorial experimental design. The objectives were to identify conditions that will maximize the yield of target plant tissue, maximize the production of secondary metabolites and minimize the variation in that value. Phosphorus concentration was varied because this nutrient is important for plant growth, particularly during flower production. Nutrient supply rates used in this study sought to minimize nutrient deficiencies and growth fluctuations. Selected plants in the study were also subjected to a clipping treatment, as numerous studies have shown that herbivory can induce increased growth ( overcompensation ) and potentially to stimulate secondary metabolite production. (Abstract shortened by UMI.)Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2002 .S74. Source: Masters Abstracts International, Volume: 42-01, page: 0150. Adviser: Lesley Lovett-Doust. Thesis (M.Sc.)--University of Windsor (Canada), 2003
The 2004 Claremont Debate: Lipsey vs. Scriven
While there is little disagreement about the need for, and value of, program evaluation, there remain major disagreements in the field about best practices (Donaldson & Lipsey, in press). For example, Donaldson and Scriven (2003) invited a diverse group of evaluators to Claremont in 2001 to share their visions for “how we should practice evaluation” in the new millennium. Theorists and practitioners discussed a wide range of views and evaluation approaches, many at odds with one another, on how best to improve evaluation practice (e.g., the experimental paradigm, evaluation as a transdiscipline, results-oriented management, empowerment evaluation, fourth generation evaluation, inclusive evaluation, theory-driven evaluation and the like). In response to some of the heated exchanges, Mark (2003) noted “it seems ironic when evaluators who espouse inclusion, empowerment, and participation would like to exclude, disempower, and see no participation by evaluators who hold different views.” Hefurther concluded that whatever peace has been achieved in the so-call quantitative-qualitative paradigm wars remains an uneasy peace
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Pattern of Mesozoic Thrust Surfaces and Tertiary Normal Faults in the Sevier Desert Subsurface, West-Central Utah
Most tectonic models for the Sevier Desert basin, west-central Utah, envision it as the result of large-magnitude, normal-sense slip on a regional detachment fault. That interpretation, based principally on seismic reflection data, has helped shape views on the tectonics of the northeastern Great Basin area and, in a larger sense, the historical development of ideas about low-angle normal faulting. In recent years, however, several researchers have suggested, based on rock-mechanical, field, and subsurface evidence, that the hypothesized detachment fault does not exist and that the basin must have another explanation. Even among proponents of the detachment model, opinion has differed regarding the hypothesized extensional fault’s total displacement, estimates for which vary widely; the timing of detachment slip; and whether the hypothesized fault represents a “new” Tertiary extensional structure or an extensional reactivation of the Mesozoic Pavant thrust. A comprehensive reinterpretation of available subsurface data for the basin, including several previously unpublished seismic profiles, suggests: (1) that slip on the hypothesized detachment must have ceased by the Miocene in the southern Sevier Desert; (2) that estimates of large-magnitude offset on the hypothesized detachment are essentially unconstrained by structural data and need to be reevaluated; and (3) that models that view the hypothesized detachment as a Tertiary extensional reactivation of a Mesozoic thrust are likely incorrect. The newly available seismic data demonstrate that reflections from the Pavant thrust do indeed closely align with reflections from the Paleozoic/Tertiary contact in many parts of the northern Sevier Desert basin; however, to the south these same thrust fault reflections are directly traceable to a position well above the down dip projection of the presumed detachment within the Paleozoic Cricket Mountains block. Erosional truncation of the thrust faults and the absence in the south of other reflections aligned with the Paleozoic/Tertiary contact preclude extensional back-sliding on a Mesozoic thrust fault. These interpretations, if correct, are incompatible with the detachment hypothesis and necessitate alternative explanations for the basin’s origins
Universal screening for meticillin-resistant Staphylococcus aureus : interim results from the NHS Scotland pathfinder project
Following recommendations from a Health Technology Assessment (HTA), a prospective cohort study of meticillin-resistant Staphylococcus aureus (MRSA) screening of all admissions (N = 29 690) to six acute hospitals in three regions in Scotland indicated that 7.5% of patientswere colonised on admission to hospital. Factors associated with colonisation included re-admission, specialty of admission (highest in nephrology, care of the elderly, dermatology and vascular surgery), increasing age, and the source of admission (care home or other hospital). Three percent of all those who were identified as colonised developed hospital-associated MRSA infection, compared with only 0.1% of those not colonised. Specialtieswith a high rate of colonisation on admission also had higher rates of MRSA infection. Very few patients refused screening (11 patients, 0.03%) or had treatment deferred (14 patients, 0.05%). Several organisational issues were identified, including difficulties in achieving complete uptake of screening (88%) or decolonisation (41%); the latter was largely due to short duration of stay and turnaround time for test results. Patient movement resulted in a decision to decontaminate all positive patients rather than just those in high risk specialties as proposed by the HTA. Issues also included a lack of isolation facilities to manage patients with MRSA. The study raises significant concerns about the contribution of decolonisation to reducing risks in hospital due to short duration of stay, and reinforces the central role of infection control precautions. Further study is required before the HTA model can be re-run and conclusions redrawn on the cost and clinical effectiveness of universal MRSA screening
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Rock Deformation Studies in the Mineral Mountains and Sevier Desert of West-Central Utah: Implications for Upper Crustal Low-Angle Normal Faulting
The Cave Canyon detachment, a low-angle normal fault that crops out in the Mineral Mountains, west-central Utah, has been interpreted as a hanging-wall splay of a much larger structure (the Sevier Desert detachment) that was influential in development of the idea that low-angle normal faults play a role in crustal extension. The Cave Canyon detachment provides expectations for the deformational features that might be expected along the hypothesized Sevier Desert detachment, which is not exposed in outcrop and is inferred to exist primarily on the basis of seismic reflection data.
The footwall of the Cave Canyon detachment is characterized by a 200-m-thick granite cataclasite, which exhibits a clear decrease in grain size and increase in microfracture density as the fault surface is approached. Undulatory extinction in quartz and feldspar and abundant quartz deformation lamellae at distances more than 200 m from the fault surface are interpreted as related to cooling of the Miocene granite rather than to normal faulting. Although mylonitic textures have previously been described in the granite, we found no evidence for mylonitization in the footwall rocks. The hanging wall of the detachment is characterized by 9 m of deformed, partially dolomitized limestone, with a 2-m-thick carbonate mylonite at the contact. Deformation features include dynamic recrystallization, grain-size reduction, development of twinning with a strong preferred orientation, some grain-size layering, and undulatory extinction close to the fault. Static recrystallization overprints fossils and ooids at distances greater than 9 m.
Drill cuttings and some core recovered at similar distances above and below the hypothesized Sevier Desert detachment show no evidence for localized deformation (ARCO Hole-in-the-Rock No. 1, ARCO Meadow Federal No. 1, and Argonaut Energy Federal No. 1 wells). Fossils and ooids are undeformed in Paleozoic carbonate rocks within 3 m below the contact, and sandstone and conglomerate with rounded clasts lacking more than background levels of microfracturing are found in samples within 3 m above the contact. These features contrast markedly with those of the Cave Canyon detachment, which was active at a considerably shallower and cooler level in the crust (∼5 km and less than 300 °C) than is implied for Paleozoic rocks beneath the Sevier Desert, once hanging-wall rocks are restored along the hypothesized detachment (9−14 km and 280−425 °C at the locations studied). The very different character of the two surfaces reinforces our earlier suggestion that beneath much of the Sevier Desert basin, the base of the Tertiary section is an unconformity rather than a low-angle normal fault
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Is the Sevier Desert Reflection of West-Central Utah a Normal Fault?: Comment and Reply
Forum discussion on an article originally by Anders et al. Allmendinger and Royse critique Anders et al.'s argument, to which Anders et al. responds.
Critique abstract: The continuing discussion of the Sevier Desert region, almost 20 years after MacDonald’s (1976) classic paper, provides a measure of the significance of the region as well as the non-uniqueness of seismic reflection data interpretation. The article by Anders and Christie-Blick (1994) and the nearly simultaneous publication of similar ideas by Hamilton (1994) raise important questions. The interpretation of a Sevier Desert detachment has always been a hypothesis to be tested rather than a fact. In our opinion, however, Anders and Christie-Blick and Hamilton have ignored a variety of basic geologic data requiring the presence of a major low-angle normal fault on the east side of the Sevier Desert basin.
Response abstract: We concur with Allmendinger and Royse’s assessment of the detachment interpretation for the Sevier Desert reflection as a ‘‘hypothesis to be tested.’’ We reported on an attempt to do just that: to look for evidence for fault-related deformation in samples from two boreholes that intersect this feature. The absence of evidence for cataclasis in the inferred hanging-wall block or ductile deformation in the footwall naturally raises some interesting issues for the tectonic interpretation of the Sevier Desert. In drawing attention to these issues, we have not ‘‘ignored’’ any basic geologic data, nor are we aware of any data that ‘‘require’’ the presence of a major low-angle normal fault
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Detrital Zircon Provenance of Mesoproterozoic to Cambrian Arenites in the Western United States and Northwestern Mexico
U-Pb isotopic dating of detrital zircon from supracrustal Proterozoic and Cambrian arenites from the western United States and northern Mexico reveal three main age groups, 1.90 to 1.62 Ga, 1.45 to 1.40 Ga, and 1.2 to 1.0 Ga. Small amounts of zircons with ages of 3.1 to 2.5 Ga, 1.57 Ga, 1.32 Ga, 1.26 Ga, 0.7 Ga, and 0.5 Ga are also present.
Detrital zircons ranging in age from 1.90 to 1.62 Ga and from 1.45 to 1.40 Ga are considered to have been derived from Proterozoic crystalline basement rocks of these known ages, and probably in part from reworked Proterozoic supracrustal sedimentary rocks, of the western United States. The 1.2 to 1.0 Ga detrital zircon ages from California, Arizona, and Sonora are characterized by distinct spikes (1.11 Ga, in particular) in the age-probability plots. These spikes are interpreted to indicate the influx of zircon from major silicic volcanic fields. Igneous rocks such as the Pikes Peak Granite (1.093 Ga) of Colorado, and the Aibo Granite (1.110 Ga) of Sonora, Mexico, may represent the deeply eroded roots of such volcanic fields. Samples from farther north along the Cordilleran margin that contain abundant 1.2–1.0 Ga detrital zircons do not show spikes in the age distribution, but rather ages spread out across the entire 1.2–1.0 Ga range. These age spectra resemble those for detrital zircons from the Grenville province, which is considered their source.
Less common detrital zircons had a variety of sources. Zircons ranging in age from 3.36 to 2.31 Ga were apparently derived from inland parts of the North American continent from Wyoming to Canada. Zircons of about 1.577 Ga are highly unusual and may have had an exotic source; they may have come from Australia and been deposited in North America when Australia and North America were juxtaposed as part of the hypothetical Rodinian supercontinent. Detrital zircon of ∼1.320 Ga apparently had the same source as that for tuff (1.320 Ga) in the Pioneer Shale of the Apache Group in Arizona. Detrital zircons of about 1.26 Ga in the Apache Group and Troy Quartzite appear to be related to local, approximately coeval volcanic fields. Zircons of about 0.7 Ga may have had a source in igneous rocks related to rifting of the Proterozoic supercontinent of Rodinia, and 0.5 Ga zircons a source in relatively small areas of granitic rocks of this known, or inferred, age in Oklahoma, Texas, New Mexico, and Colorado
The N-methyl-d-aspartate receptor antagonist CPP alters synapse and spine structure and impairs long-term potentiation and long-term depression induced morphological plasticity in dentate gyrus of the awake rat
Long-term morphological synaptic changes associated with homosynaptic long-term potentiation (LTP) and heterosynaptic long-term depression (LTD) in vivo, in awake adult rats were analyzed using three-dimensional (3-D) reconstructions of electron microscope images of ultrathin serial sections from the molecular layer of the dentate gyrus. For the first time in morphological studies, the specificity of the effects of LTP and LTD on both spine and synapse ultrastructure was determined using an N-methyl-d-aspartate (NMDA) receptor antagonist CPP (3-[(R)-2-carboxypiperazin-4-yl]-propyl-1-phosphonic acid). There were no differences in synaptic density 24 h after LTP or LTD induction, and CPP alone had no effect on synaptic density. LTP increased significantly the proportion of mushroom spines, whereas LTD increased the proportion of thin spines, and both LTP and LTD decreased stubby spine number. Both LTP and LTD increased significantly spine head evaginations (spinules) into synaptic boutons and CPP blocked these changes. Synaptic boutons were smaller after LTD, indicating a pre-synaptic effect. Interestingly, CPP alone decreased bouton and mushroom spine volumes, as well as post-synaptic density (PSD) volume of mushroom spines.These data show similarities, but also some clear differences, between the effects of LTP and LTD on spine and synaptic morphology. Although CPP blocks both LTP and LTD, and impairs most morphological changes in spines and synapses, CPP alone was shown to exert effects on aspects of spine and synaptic structure
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