132 research outputs found
Motor drivers for dc brushless motors
Nondestructive tests of motor drivers for delta wound dc brushless motor
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Are Early Summer Wildfires an Opportunity to Revegetate Exotic Annual GrassâInvaded Plant Communities?
Medusahead (Taeniatherum caput-medusae [L.] Nevski) is an exotic annual grass invading western rangelands. Successful
revegetation of invaded-plant communities can be prohibitively expensive because it often requires iterative applications of
integrated control and revegetation treatments. Prescribed burning has been used to control medusahead and prepare seedbeds
for revegetation, but burning has been constrained by liability concerns and has produced widely varying results. Capitalizing
on naturally occurring wildfires could reduce revegetation costs and alleviate liability concerns. Thus, our objective was to
determine if early summer wildfires and fall drill seeding could be used as a treatment combination to decrease medusahead and
increase perennial and native vegetation. Treatments were evaluated pretreatment and for 3 yr postfire at six sites and included
1) an early summer wildfire combined with a seeding treatment (burn and seed) and 2) a nontreated (no burn, no seed) control.
Perennial grass density was 4.6- to 10.0-fold greater in the burn-and-seed treatment compared to the control in the first 3 yr
posttreatment (P<0.05). Exotic annual grass density and cover in the third year posttreatment were lower in the burn-and-seed
treatment than in the control (P130 individuals ⢠m âťÂ˛ in the burn-andseed
treatment. The density of exotic annual grass is of concern because over time medusahead may displace perennial grasses
and annual forbs that increased with the burn-and-seed treatment. Though not directly tested in this study, we suggest that,
based on other research, the burn-and-seed treatment may need to incorporate a preemergent herbicide application to further
suppress medusahead and increase the establishment of seeded vegetation. However, it appears that early summer wildfires may
provide an opportunity to reduce the cost of integrated programs to revegetate medusahead-invaded plant communities.Keywords: Medusahead, Sagebrush, Invasive plants, Weeds, Taeniatherum caput-medusae, Restoratio
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Restoration of Mountain Big Sagebrush Steppe Following Prescribed Burning to Control Western Juniper
Western juniper (Juniperus occidentalis ssp.
occidentalis Hook) encroachment into mountain big sagebrush
(Artemisia tridentata spp. vaseyana (Rydb.) Beetle)
steppe has reduced livestock forage production, increased
erosion risk, and degraded sagebrush-associated wildlife
habitat. Western juniper has been successfully controlled
with partial cutting followed by prescribed burning the next
fall, but the herbaceous understory and sagebrush may be
slow to recover. We evaluated the effectiveness of seeding
perennial herbaceous vegetation and sagebrush at five sites
where juniper was controlled by partially cutting and prescribed
burning. Treatments tested at each site included an
unseeded control, herbaceous seed mix (aerially seeded),
and the herbaceous seed mix plus sagebrush seed. In the
third year post-treatment, perennial grass cover and density
were twice as high in plots receiving the herbaceous seed
mix compared to the control plots. Sagebrush cover and
density in the sagebrush seeded plots were between 74- and
290-fold and 62- and 155-fold greater than the other
treatments. By the third year after treatment, sagebrush
cover was as high as 12% in the sagebrush seeded plots
and between 0% and 0.4% where it was not seeded.
These results indicate that aerial seeding perennial herbaceous
vegetation can accelerate the recovery of perennial
grasses which likely stabilize the site. Our results also
suggest that seeding mountain big sagebrush after prescribed
burning encroaching juniper can rapidly recover sagebrush cover and density. In areas where sagebrush
habitat is limited, seeding sagebrush after juniper control
may increase sagebrush habitat and decrease the risks to
sagebrush-associated species.Keywords: Fire, Sage-grouse, Recovery, Aerial seeding, Habitat, Artemisia tridentataKeywords: Fire, Sage-grouse, Recovery, Aerial seeding, Habitat, Artemisia tridentat
Doing calories: the practices of dieting using calorie counting app MyFitnessPal
The existing literature on fatness has critically discussed meanings and morals associated with body weight and explored peopleâs experiences of weight loss attempts. However, little attention has been paid to the practices of dieting â how it is âdoneâ. Based on an interview study involving 31 participants, who shared their self-tracking experience of using the MyFitnessPal calorie counting app, we focus on the practices of âdoingâ calories. First, we discuss the practices of temporality of logging food, showing that the use of MyFitnessPal not only has to be fitted into daily routines but can also transform them. Then, we look at the practices of precision or usersâ various ways of turning the âmessinessâ of food into precise numbers. Lastly, we explore usersâ practices of adjustments â their attitudes to adherence to their daily calorie goal and ways of dealing with going above it. Based on our findings we suggest calorie counting is not a straightforward data collection, but one that involves constant practical strategies and negotiations, and can both influence and be influenced by other everyday practices
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Medusahead Invasion Along Unimproved Roads, Animal Trails, and Random Transects
Medusahead (Taeniatherum caput-medusae [L.] Nevski), an exotic annual grass, is rapidly spreading and
causing ecological damage across the western United States. Because this exotic plant occupies vast areas and because
management resources are limited, it is critical that land managers prioritize where they direct treatment and monitoring
efforts. Identifying where and by what means medusahead is spreading could provide valuable information to assist
in determining where prevention and control efforts should be applied. We compared medusahead invasion levels along
unimproved roads, animal trails, and random transects at 6 sites in southeastern Oregon to determine where medusahead
was more common and to identify potential vectors for its spread. Medusahead was more common and its cover
was greater along unimproved roads than along trails and random transects. Medusahead infestations were also larger
along roads. Medusahead was more common along animal trails than along random transects, but differences were less
evident. Our results suggest that medusahead spreads along roads. This outcome implies, though not conclusively, that
vehicles may be one of the most important vectors for medusahead spread. Our results also suggest that animals may be
a vector for medusahead dispersal; however, invasions were much more concentrated near roads than trails, suggesting
that medusahead management along roads should receive higher priority. Medusahead invasion is not random across
the landscape, and thus, control and monitoring efforts can be prioritized, based on potential vector pathways, to manage
this invasive plant
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Success of Seeding Native Compared with Introduced Perennial Vegetation for Revegetating Medusahead-Invaded Sagebrush Rangeland
Millions of hectares of Wyoming big sagebrush (Artemisia tridentata Nutt. subsp. wyomingensis Beetle & Young) rangeland have been invaded by medusahead (Taeniatherum caput-medusae [L] Nevski), an exotic annual grass that degrades wildlife habitat, reduces forage production, and decreases biodiversity. Revegetation of medusahead-invaded sagebrush plant communities is necessary to restore ecosystem services. Disagreement, however, exists over whether to seed native or introduced perennial species to revegetate communities after controlling medusahead. Though native species generally do not establish as well as introduced species, interference from co-seeded introduced species has often been attributed to the limited success of natives. The potential for seeding natives to revegetate communities after medusahead control is relatively unknown because they have been largely co-seeded with introduced species. We compared the results of seeding native and introduced perennial species after controlling medusahead with prescribed burning followed with an imazapic herbicide application at five sites. Perennial bunchgrass cover and density were 5- and 10- fold greater in areas seeded with introduced compared with native species 3 years post seeding. Furthermore, exotic annual grass cover and density were less in areas seeded with introduced compared with native species. Seeded introduced and native shrubs largely failed to establish. High perennial bunchgrass density (15 individuals mâťÂ˛) in areas seeded with introduced species in the third year post seeding suggests that the succession trajectory of these communities has shifted to becoming perennial dominated. Average perennial bunchgrass density of 1.5 individuals mâťÂ˛ with seeding native species will likely not limit medusahead and appears to already be converting back to exotic annual grass-dominated communities. These results suggest that seeding introduced compared with native species after medusahead control will likely be more successful. Our results also imply that if natives are selected to seed after medusahead control, additional resources may be necessary to recontrol medusahead and repeatedly sow native species.Keywords: Restoration, Forage kochia, Bunchgrasses, Crested wheatgrass, Exotic annual grasses, Imazapic, Wyoming big sagebrus
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Can Imazapic and Seeding Be Applied Simultaneously to Rehabilitate Medusahead-Invaded Rangeland? Single vs. Multiple Entry
It has recently been proposed that the cost of rehabilitating medusahead (Taeniatherum caput-medusae [L.] Nevski)-invaded
rangelands may be reduced by concurrently seeding desired vegetation and applying the preemergent herbicide imazapic.
However, the efficacy of this ââsingle-entryââ approach has been inconsistent, and it has not been compared to the multiple-entry
approach where seeding is delayed 1 yr to decrease herbicide damage to nontarget seeded species. We evaluated single- and
multiple-entry approaches in medusahead-invaded rangelands in southeastern Oregon with seeding for both approaches
occurring in October 2011. Before seeding and applying herbicide, all plots were burned to improve medusahead control with
imazapic and prepare the seedbed for drill seedingâintroduced perennial bunchgrasses. Both approaches effectively controlled
medusahead during the 2 yr postseeding. However, almost no seeded bunchgrasses established with the single-entry treatment
(< 0.5 individals ⢠mâťÂ˛), probably as a result of nontarget herbicide mortality. Perennial grass cover and density in the single-entry
treatment did not differ from the untreated control. In contrast, the multiple-entry treatment had on average 6.5 seeded
bunchgrasses ⢠mâťÂ˛ in the second year postseeding. Perennial grass (seeded and nonseed species) cover was eight times greater in
the multiple-entry compared to the single-entry treatment by the second year postseeding. These results suggest that the
multiple-entry approach has altered the community from annual-dominated to perennial grass-dominated, but the single-entry
approach will likely be reinvaded and dominated medusahead without additional treatments because of a lack of perennial
vegetation.Keywords: Revegetation, Invasive plants, Sagebrush, Preemergent herbicide, Taeniatherum caputmedusae, Annual grass controlKeywords: Revegetation, Invasive plants, Sagebrush, Preemergent herbicide, Taeniatherum caputmedusae, Annual grass contro
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Is fire exclusion in mountain big sagebrush communities prudent? Soil nutrient, plant diversity and arthropod response to burning
Fire has largely been excluded from many mountain big sagebrush communities. Managers are reluctant to
reintroduce fire, especially in communities without significant conifer encroachment, because of the decline in sagebrush-associated
wildlife. Given this management direction, a better understanding of fire exclusion and burning effects is
needed. We compared burned to unburned plots at six sites in Oregon. Soil nutrient availability generally increased with
burning. Plant diversity increased with burning in the first post-burn year, but decreased by the third post-burn year.
Burning altered the arthropod community, which included doubling the density of arthropods in the first post-burn year.
Some arthropod Orders increased and others decreased with burning. For example, Araneae were 1.7- and 1.8-fold less and
Hemiptera were 6.6- and 2.1-fold greater in the burn compared with the control in 2008 and 2009. Our results provide
evidence that burning can create spatial and temporal heterogeneity in sagebrush communities and thus, it is an important
component of the ecosystem. We suggest that management plans for many mountain big sagebrush communities may need
to include infrequent burning. At the very least managers should be aware that fire exclusion has some potentially negative
effects other than the encroachment of conifers in these communities.Keywords: Biodiversity, Spatial heterogeneity, Fire management, Disturbance, Artemisia tridentat
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Beauty surveillance: the digital self-monitoring cultures of neoliberalism
This paper argues that âbeauty appsâ are transforming the arena of appearance politics and foregrounds a theoretical architecture for critically understanding them. Informed by a feminist-Foucaultian framework, it argues that beauty apps offer a technology of gender which brings together digital self-monitoring and postfeminist modalities of subjecthood to produce an hitherto unprecedented regulatory gaze upon women that is marked by the intensification, extensification and psychologization of surveillance.
The paper is divided into four sections. First it introduces the literature on digital self-tracking. Secondly it sets out our understanding of neoliberalism and postfeminism. Thirdly it looks at beauty and surveillance, before offering, in the final section, a typology of appearance apps. This is followed by a discussion of the modes of address/authority deployed in these apps â especially what we call âsurveillant sisterhoodâ - and the kinds of entrepreneurial subjectivity they constitute. The paper seeks to make a contribution to feminist surveillance studies and argues that much more detailed research is needed to critically examine beauty apps
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