1,775 research outputs found
Prosthetic Foot Shell, QL+
This final design review includes an overview of our project and the steps we have taken to create our final product. We discuss the background research conducted, including various products like the foot shell we are trying to design and its related patents, along with similar past senior projects. As our product is considered a medical device, there are also certain standards that we must comply with. After determining our problem statement, we established what we believe to be the wants and needs of our user. These wants and needs were converted into specifications for our design, with durability as a main goal. These specifications were used to brainstorm initial design ideas through concept modeling. There are various images and diagrams of these models that we use to support our reasonings. A preliminary design solution was chosen after an analysis was performed on our concept models. We conclude the report with an overview of the steps we took to complete our project and design and manufacture a durable prosthetic foot shell as well as future plans for testing and manufacturing a full-size foot shell prototype. A summary of our conclusions and recommendations for next steps wrap up the project
PucC and LhaA direct efficient assembly of the light-harvesting complexes in <i>Rhodobacter sphaeroides</i>
The mature architecture of the photosynthetic membrane of the purple phototroph Rhodobacter sphaeroides has been characterised to a level where an atomic-level membrane model is available, but the roles of the putative assembly proteins LhaA and PucC in establishing this architecture are unknown. Here we investigate the assembly of light-harvesting LH2 and reaction centre-light-harvesting1-PufX (RC-LH1-PufX) photosystem complexes using spectroscopy, pull-downs, native gel electrophoresis, quantitative mass spectrometry and fluorescence lifetime microscopy to characterise a series of lhaA and pucC mutants. LhaA and PucC are important for specific assembly of LH1 or LH2 complexes, respectively, but they are not essential; the few LH1 subunits found in ΔlhaA mutants assemble to form normal RC-LH1-PufX core complexes showing that, once initiated, LH1 assembly round the RC is cooperative and proceeds to completion. LhaA and PucC form oligomers at sites of initiation of membrane invagination; LhaA associates with RCs, bacteriochlorophyll synthase (BchG), the protein translocase subunit YajC and the YidC membrane protein insertase. These associations within membrane nanodomains likely maximise interactions between pigments newly arriving from BchG and nascent proteins within the SecYEG-SecDF-YajC-YidC assembly machinery, thereby co-ordinating pigment delivery, the co-translational insertion of LH polypeptides and their folding and assembly to form photosynthetic complexes. LhaA and PucC form oligomers at the sites where invagination of the cytoplasmic membranes is initiated, and they play important roles in photosystem assembly in the purple phototrophic bacterium Rhodobacter sphaeroides. Establishing the architecture of the photosynthetic membrane involves interplay between LhaA, reaction centre complexes, bacteriochlorophyll synthase, the protein translocase subunit YajC, and the YidC membrane protein insertase. These associations likely coordinate the delivery of pigments and the membrane insertion, folding and assembly of photosystem polypeptides
Deflection of Highly Relativistic Particles in a Gravitational Field
A novel approach to the calculation of the deflection of highly relativistic
test particles in gravitational fields is described. We make use of the
light-like boosts of the gravitational fields of the sources. Examples are
given of the deflection of highly relativistic particles in the Schwarzschild
and Kerr gravitational fields, in the field of a static, axially symmetric,
multipole source and in the field of a cosmic string. The deflection of
spinning particles is also discussed.Comment: 18 pages, 2 figures, accepted for publication in Classical and
Quantum Gravit
Future local passenger transport system scenarios and implications for policy and practice
The world is rapidly changing and the future is uncertain, yet until recently the dominant assumption of the local passenger transport community has been that the existing modal landscape of cars, buses and taxis will remain much as it is now. Such a view is now shifting however, with decision makers now appreciating the need to understand the implications of potentially radical changes in the technological, political, economic, social and environmental spheres. Accordingly, in August 2015 the Public Transport 2045 study was commissioned to consider how different local public transport futures might affect society over the next 30-years, and at how governments might best respond.
The multi-phase study was based on individual in-depth interviews with 50 senior local passenger transport operators, government officials, lobbyists and experts from New Zealand and around the world; and four validation workshops with 28 sector stakeholders. The data was analysed using mostly pre-determined themes from which four scenarios were constructed and then validated. The implications are that the transport system is about to transition to a system of ‘shared mobility’; public transport will need to evolve to stay relevant but will remain important in any scenario; and the role of Government will be vital in overseeing the transition to the shared mobility era. These lessons are now being used to inform transport and broader policy decisions across New Zealand. Overall, the study is the first to apply such a global and qualitatively rich dataset to view the long-term future passenger transport system as a whole
The Optical Design and Characterization of the Microwave Anisotropy Probe
The primary goal of the MAP satellite, now in orbit, is to make high fidelity
polarization sensitive maps of the full sky in five frequency bands between 20
and 100 GHz. From these maps we will characterize the properties of the cosmic
microwave background (CMB) anisotropy and Galactic and extragalactic emission
on angular scales ranging from the effective beam size, <0.23 degree, to the
full sky. MAP is a differential microwave radiometer. Two back-to-back shaped
offset Gregorian telescopes feed two mirror symmetric arrays of ten corrugated
feeds. We describe the prelaunch design and characterization of the optical
system, compare the optical models to the measurements, and consider multiple
possible sources of systematic error.Comment: ApJ in press; 22 pages with 11 low resolution figures; paper is
available with higher quality figures at
http://map.gsfc.nasa.gov/m_mm/tp_links.htm
Assessing the psychometric and ecometric properties of neighborhood scales using adolescent survey data from urban and rural Scotland
This work was supported by NHS Health Scotland and the University of St Andrews.Background: Despite the well-established need for specific measurement instruments to examine the relationship between neighborhood conditions and adolescent well-being outcomes, few studies have developed scales to measure features of the neighborhoods in which adolescents reside. Moreover, measures of neighborhood features may be operationalised differently by adolescents living in different levels of urban/rurality. This has not been addressed in previous studies. The objectives of this study were to: 1) establish instruments to measure adolescent neighborhood features at both the individual and neighborhood level, 2) assess their psychometric and ecometric properties, 3) test for invariance by urban/rurality, and 4) generate neighborhood level scores for use in further analysis. Methods: Data were from the Scottish 2010 Health Behaviour in School-aged Children Survey, which included an over-sample of rural adolescents. The survey responses of interest came from questions designed to capture different facets of the local area in which each respondent resided. Intermediate data zones were used as proxies for neighborhoods. Internal consistency was evaluated by Cronbach’s alpha. Invariance was examined using confirmatory factor analysis. Multilevel models were used to estimate ecometric properties and generate neighborhood scores. Results: Two constructs labeled neighborhood social cohesion and neighborhood disorder were identified. Adjustment was made to the originally specified model to improve model fit and measures of invariance. At the individual level, reliability was .760 for social cohesion and .765 for disorder, and between .524 and .571 for both constructs at the neighborhood level. Individuals in rural areas experienced greater neighborhood social cohesion and lower levels of neighborhood disorder compared with those in urban areas. Conclusions: The scales are appropriate for measuring neighborhood characteristics experienced by adolescents across urban and rural Scotland, and can be used in future studies of neighborhoods and health. However, trade-offs between neighborhood sample size and reliability must be considered.Publisher PDFPeer reviewe
The BLAST View of the Star Forming Region in Aquila (ell=45deg,b=0deg)
We have carried out the first general submillimeter analysis of the field
towards GRSMC 45.46+0.05, a massive star forming region in Aquila. The
deconvolved 6 deg^2 (3\degree X 2\degree) maps provided by BLAST in 2005 at
250, 350, and 500 micron were used to perform a preliminary characterization of
the clump population previously investigated in the infrared, radio, and
molecular maps. Interferometric CORNISH data at 4.8 GHz have also been used to
characterize the Ultracompact HII regions (UCHIIRs) within the main clumps. By
means of the BLAST maps we have produced an initial census of the submillimeter
structures that will be observed by Herschel, several of which are known
Infrared Dark Clouds (IRDCs). Our spectral energy distributions of the main
clumps in the field, located at ~7 kpc, reveal an active population with
temperatures of T~35-40 K and masses of ~10^3 Msun for a dust emissivity index
beta=1.5. The clump evolutionary stages range from evolved sources, with
extended HII regions and prominent IR stellar population, to massive young
stellar objects, prior to the formation of an UCHIIR.The CORNISH data have
revealed the details of the stellar content and structure of the UCHIIRs. In
most cases, the ionizing stars corresponding to the brightest radio detections
are capable of accounting for the clump bolometric luminosity, in most cases
powered by embedded OB stellar clusters
A model of the anisotropic correlation function xi(rp, pi) in redshift space including redshift errors
With the advent of very large volume, wide-angle photometric redshift surveys
like e.g. Pan-STARRS, DES, or PAU, which aim at using the spatial distribution
of galaxies as a means to constrain the equation of state parameter of dark
energy, w_DE, it has become extremely important to understand the influence of
redshift inaccuracies on the measurement. We have developed a new model for the
anisotropic two point large-scale (r > 64 h^-1 Mpc) correlation function
xi(rp,pi), in which nonlinear structure growth and nonlinear coherent infall
velocities are taken into account, and photometric redshift errors can easily
be incorporated. In order to test its validity and investigate the effects of
photometric redshifts, we compare our model with the correlation function
computed from a suite of 50 large-volume, moderate-resolution numerical N-body
simulation boxes, where we can perform the analysis not only in real- and
redshift space, but also simulate the influence of a gaussian redshift error
distribution with an absolute rms of sigma_z= 0.015, 0.03, 0.06, and 0.12,
respectively. We conclude that for the given volume (V_box =2.4 h^-3 Gpc^3) and
number density (n ~ 1.25 10^-4) of objects the full shape of xi(rp,pi) is
modeled accurately enough to use it to derive unbiased constraints on the
equation of state parameter of dark energy w_DE and the linear bias b, even in
the presence of redshift errors of the order of sigma_z = 0.06.Comment: Accepted for publication by MNRA
Simulating the influences of groundwater on regional geomorphology using a distributed, dynamic, landscape evolution modelling platform
A dynamic landscape evolution modelling platform (CLiDE) is presented that allows a variety of Earth system interactions to be explored under differing environmental forcing factors. Representation of distributed surface and subsurface hydrology within CLiDE is suited to simulation at sub-annual to centennial time-scales. In this study the hydrological components of CLiDE are evaluated against analytical solutions and recorded datasets. The impact of differing groundwater regimes on sediment discharge is examined for a simple, idealised catchment, Sediment discharge is found to be a function of the evolving catchment morphology. Application of CLiDE to the upper Eden Valley catchment, UK, suggests the addition of baseflow-return from groundwater into the fluvial system modifies the total catchment sediment discharge and the spatio-temporal distribution of sediment fluxes during storm events. The occurrence of a storm following a period of appreciable antecedent rainfall is found to increase simulated sediment fluxes
General Analysis of Antideuteron Searches for Dark Matter
Low energy cosmic ray antideuterons provide a unique low background channel
for indirect detection of dark matter. We compute the cosmic ray flux of
antideuterons from hadronic annihilations of dark matter for various Standard
Model final states and determine the mass reach of two future experiments
(AMS-02 and GAPS) designed to greatly increase the sensitivity of antideuteron
detection over current bounds. We consider generic models of scalar, fermion,
and massive vector bosons as thermal dark matter, describe their basic features
relevant to direct and indirect detection, and discuss the implications of
direct detection bounds on models of dark matter as a thermal relic. We also
consider specific dark matter candidates and assess their potential for
detection via antideuterons from their hadronic annihilation channels. Since
the dark matter mass reach of the GAPS experiment can be well above 100 GeV, we
find that antideuterons can be a good indirect detection channel for a variety
of thermal relic electroweak scale dark matter candidates, even when the rate
for direct detection is highly suppressed.Comment: 44 pages, 15 Figure
- …