10,541 research outputs found
Contact structures, deformations and taut foliations
Using deformations of foliations to contact structures as well as rigidity
properties of Anosov foliations we provide infinite families of examples which
show that the space of taut foliations in a given homotopy class of plane
fields is in general not path connected. Similar methods also show that the
space of representations of the fundamental group of a hyperbolic surface to
the group of smooth diffeomorphisms of the circle with fixed Euler class is in
general not path connected. As an important step along the way we resolve the
question of which universally tight contact structures on Seifert fibered
spaces are deformations of taut or Reebless foliations when the genus of the
base is positive or the twisting number of the contact structure in the sense
of Giroux is non-negative.Comment: 37 pages, 2 figures; Improved exposition incorporating referee's
comments mainly in Sections 5 and 9. (To appear in Geom. Topol.
Exactly fillable contact structures without Stein fillings
We give examples of contact structures which admit exact symplectic fillings,
but no Stein fillings, answering a question of Ghiggini.Comment: 6 pages; Erroneous Lemma 2.7 removed and Section 2 shortened
significantly; updated references and other minor edits (to appear in Algebr.
Geom. Topol.
Local Languages, Local Malay, and Bahasa Indonesia; a Case Study From North Maluku
Many small languages from eastern Indonesia are threatened with extinction. While it is often assumed that ‘Indonesian' is replacing the lost languages, in reality, local languages are being replaced by local Malay. In this paper I review some of the reasons for this in North Maluku. I review the directional system in North Maluku Malay and argue that features like the directionals allow those giving up local languages to retain a sense of local linguistic identity. Retaining such an identity makes it easier to abandon local languages than would be the case if people were switching to ‘standard' Indonesian
Assessment of Southern California environment from ERTS-1
ERTS-1 imagery is a useful source of data for evaluation of earth resources in Southern California. The improving quality of ERTS-1 imagery, and our increasing ability to enhance the imagery has resulted in studies of a variety of phenomena in several Southern California environments. These investigations have produced several significant results of varying detail. They include the detection and identification of macro-scale tectonic and vegetational patterns, as well as detailed analysis of urban and agricultural processes. The sequential nature of ERTS-1 imagery has allowed these studies to monitor significant changes in the environment. In addiation, some preliminary work has begun directed toward assessing the impact of expanding recreation, agriculture and urbanization into the fragile desert environment. Refinement of enhancement and mapping techniques and more intensive analysis of ERTS-1 imagery should lead to a greater capability to extract detailed information for more precise evaluations and more accurate monitoring of earth resources in Southern California
Cadmium sulfide in a Mesoproterozoic terrestrial environment
Peer reviewedPostprin
Land use in the northern Coachella Valley
Satellite imagery has proved to have great utility for monitoring land use change and as a data source for regional planning. In California, open space desert resources are under severe pressure to serve as a source for recreational gratification to individuals living in the heavily populated southern coastal plain. Concern for these sensitive arid environments has been expressed by both federal and state agencies. The northern half of the Coachella Valley has historically served as a focal point for weekend recreational activity and second homes. Since demand in this area has remained high, land use change from rural to urban residential has been occurring continuously since 1968. This area of rapid change is an ideal site to illustrate the utility of satellite imagery as a data source for planning information, and has served as the areal focus of this investigation
Quiet Clean Short-haul Experimental Engine (QCSEE). Composite fan frame subsystem test report
The element and subcomponent testing conducted to verify the composite fan frame design of two experimental high bypass geared turbofan engines and propulsion systems for short haul passenger aircraft is described. Emphasis is placed on the propulsion technology required for future externally blown flap aircraft with engines located both under the wing and over the wing, including technology in composite structures and digital engine controls. The element tests confirmed that the processes used in the frame design would produce the predicted mechanical properties. The subcomponent tests verified that the detail structural components of the frame had adequate structural integrity
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