4,036 research outputs found
Making Photographs Speak
It has often been said that “a picture is worth a thousand words.” Making that picture spit out those mythical thousand words, as we can all attest, is no easy task. Over the course of the first half of the fall semester, the three of us were tasked with developing brief interpretive captions for two Civil War photographs each, with the end goal to display our work at the Civil War Institute’s 2019 Summer Conference. What initially appeared as a simple project quickly revealed itself to be a difficult, yet rewarding, challenge that taught us all important lessons concerning history, photography, and writing that we will not soon forget. Producing the photography exhibit enhanced our skills as historical writers, introduced us to the challenge of writing for a popular audience, and deepened our understanding of Civil War photography. [excerpt
Characterization and Commissioning of a Ka-Band Ground Station for Cognitive Algorithm Development
In 2018, the Cognitive Communications and Propagation projects completed installation and checkout testing of a new Ka-Band ground station at the NASA Glenn Research Center in Cleveland, Ohio. The Cognitive Algorithms Demonstration Testbed (CADeT) was developed to provide a fully characterized and controllable dynamic link environment to researchers looking to demonstrate hardware and software aligned with atmospheric sensing and cognitive algorithms. CADeT integrates a host of precision control and measurement systems in addition to repurposing a 5.5 meter beam-waveguide dish platform previously used with the Advanced Communications Technology Satellite (ACTS). This paper will discuss the laboratory testing of ground station components with a emphasis on elements vital to achieving link budget requirements including characterization of the new Gallium Nitride (GaN) Solid State Power Amplifier (SSPA) and far-field measurements of the new antenna feed. Finally, the paper discusses in-situ tests conducted with CADeT and the Tracking and Data Relay Satellite System (TDRSS) to validate laboratory results and make necessary link budget adjustments before reviewing the lessons learned
X-ray Emission From Nearby M-dwarfs: the Super-saturation Phenomenon
A rotation rate and X-ray luminosity analysis is presented for rapidly
rotating single and binary M-dwarf systems. X-ray luminosities for the majority
of both single & binary M-dwarf systems with periods below days
(equatorial velocities, V 6 km~s) are consistent with the
current rotation-activity paradigm, and appear to saturate at about
of the stellar bolometric luminosity. The single M-dwarf data show tentative
evidence for the super-saturation phenomenon observed in some ultra-fast
rotating ( 100 km~s) G & K-dwarfs in the IC 2391, IC 2602 and Alpha
Persei clusters. The IC 2391 M star VXR60b is the least X-ray active and most
rapidly rotating of the short period (P 2 days) stars considered
herein, with a period of 0.212 days and an X-ray activity level about 1.5 sigma
below the mean X-ray emission level for most of the single M-dwarf sample. For
this star, and possibly one other, we cautiously believe that we have
identified the first evidence of super-saturation in M-dwarfs. If we are wrong,
we demonstrate that only M-dwarfs rotating close to their break up velocities
are likely to exhibit the super-saturation effect at X-ray wavelengths.Comment: 12 pages, 4 figures, accepted by MNRA
A study of the factors that assisted and directed Scottish emigration to Upper Canada, 1815-1855
The first half of the nineteenth century witnessed the
beginning of large scale emigration between Scotland and the British colony of Upper Canada. In any migration there are a
number of factors which act as obstacles to the migration flow
and a number of agencies (factors) which operate to overcome
these obstacles.
This study examines in turn those factors that assisted
and directed Scottish emigration to Upper Canada between 1815
and 1855. Its focus is on a dynamic aspect of population -
migration - and it examines in detail the spatial distribution
of a variety of factors, influencing and directing the movements
of large numbers of people.
Eight major factors are evaluated as to their influence
over time on the character, volume and direction of this
emigration. These eight factors are qualitatively ranked
on the basis of the factors' role in overcoming various obstacles
and the number of emigrants who were assisted and influenced.
The three factors in the first order are friends and
relatives; periodicals, newspapers and books; and Scottish
ports, shipping and emigration agents. These three factors
were all of critical importance by acting as positive and
continuing links in the migration process, through the provision
of information, encouragement and an organizational structure.
The three factors in the second order - government; emigration
societies and trade unions; and landlords were in some ways
less significant in the overall emigration. These factors
generally tended to act as positive links in the migration
process during limited time periods and in specific areas. The
two factors in the third order - land companies and land
speculators in Upper Canada and churches were relatively the
least significant. They often related to small groups and
individual personalities and tended to be of more significance
when the emigrants began to settle in their new environment.
The first half of the nineteenth century was a period
of tremendous change and development both in Scotland and in
Upper Canada. This study examines a significant yet often
neglected aspect of this process of change
Western Australian readings
When Churchlands College of Advanced Education opened in February, 1972 the first students undertook a short course in West Australian history, with particular emphasis on discovery, settlement and the gold boom of the 1890\u27s. The course has gradually expanded and Western Australian Readings is an attempt to compile a limited collection of source material to which students can refer
The Effect of Increasing Age on the Concentric and Eccentric Contractile Properties of Isolated Mouse Soleus and Extensor Digitorum Longus Muscles
There is currently a limited amount of literature investigating the age-related changes in eccentric muscle function in vitro. The present study uniquely uses the work loop technique, to better replicate in vivo muscle function, in the assessment of the age and muscle-specific changes in acute and sustained concentric and eccentric power and recovery. Whole soleus or EDL muscles were isolated from 10-week and 78-week old mice, and acute and sustained concentric and eccentric work loop power assessed. Despite an age-related increase in body and muscle mass, peak absolute power for both muscles was unaffected by age. Peak concentric power normalised to muscle mass declined significantly for each muscle, whilst peak normalised eccentric power declined only for soleus. Fatigue resistance and recovery for the soleus did not differ between age or contraction type. Older EDL was less resistant to concentric fatigue, but was better able to withstand sustained eccentric activity than young EDL. We have shown that age-related changes in muscle quality are more limited for eccentric function than concentric function. A greater bodily inertia is likely to further reduce in vivo locomotor performance in older animals.</p
Functional network changes and cognitive control in schizophrenia
Cognitive control is a cognitive and neural mechanism that contributes to managing the complex demands of day-to-day life. Studies have suggested that functional impairments in cognitive control associated brain circuitry contribute to a broad range of higher cognitive deficits in schizophrenia. To examine this issue, we assessed functional connectivity networks in healthy adults and individuals with schizophrenia performing tasks from two distinct cognitive domains that varied in demands for cognitive control, the RiSE episodic memory task and DPX goal maintenance task. We characterized general and cognitive control-specific effects of schizophrenia on functional connectivity within an expanded frontal parietal network (FPN) and quantified network topology properties using graph analysis. Using the network based statistic (NBS), we observed greater network functional connectivity in cognitive control demanding conditions during both tasks in both groups in the FPN, and demonstrated cognitive control FPN specificity against a task independent auditory network. NBS analyses also revealed widespread connectivity deficits in schizophrenia patients across all tasks. Furthermore, quantitative changes in network topology associated with diagnostic status and task demand were observed. The present findings, in an analysis that was limited to correct trials only, ensuring that subjects are on task, provide critical insights into network connections crucial for cognitive control and the manner in which brain networks reorganize to support such control. Impairments in this mechanism are present in schizophrenia and these results highlight how cognitive control deficits contribute to the pathophysiology of this illness
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