3,623 research outputs found
CELSS and regenerative life support for manned missions to MARS
In the mid 1990's, the space station will become a point from which inter-planetary vehicles can be launched. The practicalities of a manned Mars mission are now being studied, along with some newer concepts for human life support. Specifically, the use of organisms such as plants and algae as the basis for life support systems is now being actively considered. A Controlled Ecological Life Support System (CELSS) is composed of several facilities: (1) to grow photosynthetic plants or algae which will produce food, oxygen and potable water, and remove carbon dioxide exhaled by a crew; (2) to process biomass into food; (3) to oxidize organic wastes into CO2; and (4) to maintain system operation and stability. Such a system, when compared to using materials stored at launch, may have distinct weight and cost advantages, depending upon crew size and mission duration, as well as psychological benefits for the crew. The use of the system during transit, as well as in establishing a re-visitable surface camp, will increase the attractiveness of the CELSS concept for life support on interplanetary missions
Look Who\u27s Talking: A Multi-Case Study of In-service English Language Arts Teachers\u27 Conceptions and Uses of Discussion in the Secondary Classroom
Educational scholars and practitioners recognize that classroom discussion offers great promise for helping students develop content knowledge, critical thinking skills, and a variety of meta-cognitive and process skills associated with learning content knowledge and disciplinary processes. Despite this research-based and anecdotal consensus regarding the value of discussion, an equally extensive body of research shows that discussion is not used in U.S. classrooms as consistently or effectively as it might be. This study sought to examine this issue by exploring the relationship between in-service English language arts teachers\u27 beliefs about discussion, their goals for the use of discussion, and their actual use of discussion in the secondary English language arts classroom. The present qualitative multi-case study examined how three experienced English language arts teachers in a large southeastern school district defined and used discussion. Findings suggest that English language arts teachers recognize the value of discussion, associating it with a variety of pedagogical outcomes; however, they use it with varying degrees of effectiveness. This study has potential to make a substantial contribution to both the fields of teacher education and English education by providing scholars in both fields with a better understanding of how teachers conceptualize discussion as a pedagogical approach and the extent to which they can connect the practice with theories of literacy education
The Three Component Electronic Structure of the Cuprates Derived from SI-STM
We present a phenomenological model that describes the low energy electronic
structure of the cuprate high temperature superconductor Bi2Sr2CaCu2O8+x as
observed by Spectroscopic Imagining Scanning Tunneling Microscopy (SI-STM). Our
model is based on observations from Quasiparticle Interference (QPI)
measurements and Local Density of States (LDOS) measurements that span a range
of hole densities from critical doping, p~0.19, to extremely underdoped,
p~0.06. The model presented below unifies the spectral density of states
observed in QPI studies with that of the LDOS. In unifying these two separate
measurements, we find that the previously reported phenomena, the Bogoliubov
QPI termination, the checkerboard conductance modulations, and the pseudogap
are associated with unique energy scales that have features present in both the
q-space and LDOS(E) data sets
Getting Up to Speed: Acceleration Strategies in the Florida Scrub Lizard, \u3cem\u3eSceloporus woodi\u3c/em\u3e
Small animals typically rely on quick bursts and intermittent pauses when moving in the wild. Hence, the study of acceleration capacity is important for understanding the ecology and evolution of locomotor performance. In this study, we investigate intraspecific variation in the acceleration capacity of a small lizard (Sceloporus woodi). To quantify animal acceleration performance, the momentumāimpulse theorem is applied to data collected from highāspeed video recordings of individuals accelerating from a standstill and over a subsequent distance of 0.4 m. Unlike earlier studies, the momentumāimpulse approach allows one to directly and precisely quantify the per step contribution to acceleration capacity. Like other small vertebrates, we show that S. woodi is capable of accelerating to near maximum speeds (ā¼2 m sā1) within ā¼0.4 m and needs only a few steps (at least five) to achieve maximum speed. However, considerable intraspecific variation in acceleration capacity exists; individuals take different numbers of steps (two to five steps) over the first 0.4 m, and only some individuals (10 of 19) reach their maximum speed over the first 0.4 m. Only acceleration performance in steps 1 and 2 is predictive of running speed at 0.4 m; accelerations in steps 3, 4, and 5 are not related to individual differences in speed. Individual variation in acceleration strategy is considerable, with individuals using one of three strategies to reach maximum speed. Muscle massāspecific power during acceleration approaches the maximum power output measured for lizard hindlimb musculature (ā¼900 W kgā1), suggesting that S. woodi accelerations approach the limit of their musculoskeletal system. This study highlights the utility of the momentumāimpulse approach to study acceleration performance and the importance of elucidating the per step contribution to acceleration capacity
Studies at Oyster Bay in Jamaica, West Indies. I. Intensity patterns of bioluminescence in a natural environment
Night and day patterns in the intensities of stimulable bioluminescense in Pyrodinium bahamense were measured during the period of April 1966 through May 1967 in Oyster Bay, Falmouth Harbor, Jamaica, West Indiesā¦
Making automation pay - cost & throughput trade-offs in the manufacture of large composite components
The automation of complex manufacturing operations can provide significant savings over manual processes, and there remains much scope for increasing automation in the production of large scale structural composites. However the relationships between driving variables are complex, and the achievable throughput rate and corresponding cost for a given design are often not apparent. The deposition rate, number of machines required and unit production rates needed are interrelated and consequently the optimum unit cost is difficult to predict. A detailed study of the costs involved for a series of composite wing cover panels with different manufacturing requirements was undertaken. Panels were sized to account for manufacturing requirements and structural load requirements allowing both manual and automated lay-up procedures to influence design. It was discovered that the introduction of automated tape lay-up can significantly reduce material unit cost, and improve material utilisation, however higher production rates are needed to see this benefit
Balloon-borne radiometer measurement of Northern Hemisphere mid-latitude stratospheric HNO3 profiles spanning 12 years
Low-resolution atmospheric thermal emission spectra collected by balloon-borne radiometers over the time span of 1990ā2002 are used to retrieve vertical profiles of HNO3, CFC-11 and CFC-12 volume mixing ratios between approximately 10 and 35 km altitude. All of the data analyzed have been collected from launches from a Northern Hemisphere mid-latitude site, during late summer, when stratospheric dynamic variability is at a minimum. The retrieval technique incorporates detailed forward modeling of the instrument and the radiative properties of the atmosphere, and obtains a best fit between modeled and measured spectra through a combination of onion-peeling and global optimization steps. The retrieved HNO3 profiles are consistent over the 12-year period, and are consistent with recent measurements by the Atmospheric Chemistry Experiment-Fourier transform spectrometer satellite instrument. This suggests that, to within the errors of the 1990 measurements, there has been no significant change in the HNO3 summer mid-latitude profile
Researcher centred data repository workflows
Supporting the management of research data in universities
requires a range of services and components, including
a long-term vehicle for archiving and sharing data. Such data
repositories can serve multiple functions, and ensuring they
engage with researchers through appropriate workflows is a
key challenge. Data.uel, a new data repository at the University
of East London, seeks to provide workflows for four use cases
appropriate to institutions with a smaller research base.
It provides researcher-centred workflows for depositing
datasets, which can happen in advance of an overarching
description of a research project or following it. Accordingly,
the repository has a data model that permits the creation
of a record for a single or multiple assets, and for records
to be related to siblings as well as to parents. The data
may also be deposited before or after a related publication
is added to the publications repository (ROAR).
A separate data repository was created for two reasons:
to customise ingest to relate closely to scholarly workflows,
and to enable the addition of data that was not Open. We
know that not all data can or should be Open, so allow
researchers to make their data available in a choice of
three ways: Open Access, using open licensing; Available
on Request, where the data owner would approve
release case-by-case; and Closed to all but depositor and
administrator, where data has to be kept for compliance/
evidentiary reasons but is not suitable for sharing
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