188 research outputs found
Variability in Militia and Regular Army Refuse Disposal Patterns at Fort Meigs: A Fortified War of 1812 Encampment on the Maumee River in Northern Ohio
During the fall of 1812, Fort Meigs was built on a bluff along the south side of the Maumee River, Ohio, to serve as a forward supply base and to provide protection to the expeditionary force preparing to advance against Fort Malden. The completed fortification included batteries, blockhouses, and a connecting parapet and palisade. Three groups of Americans (federal army, militia, and volunteers) resided at Fort Meigs during its construction, usage as a base camp and forward-supply depot, and its defense. Members of these groups came from a range of socioeconomic classes. This article seeks to elucidate any qualitative differences in the behavior and refuse-disposal patterns among the three categories of soldier at Fort Meigs: militia and volunteers, enlisted men, and officers, and how disposal patterns reflect then-extant military culture. It should be possible to relate the forms of material culture discovered in contexts other than sinks (also known as primary, secondary, and de facto disposal types) (Schiffer 1972), to the actions of the three categories of soldiers
Context and Usability Testing: User-Modeled Information Presentation in Easy and Difficult Driving Conditions
A 2x2 enhanced Wizard-of-Oz experiment (N = 32) was
conducted to compare two different approaches to
presenting information to drivers in easy and difficult
driving conditions. Data of driving safety, evaluation of the
spoken dialogue system, and perception of self were
analyzed. Results show that the user-modeled summarizeand-
refine (UMSR) approach led to more efficient
information retrieval than did the summarize-and-refine
(SR) approach. However, depending on driving condition,
higher efficiency did not always translate into pleasant
subjective experience. Implications for usability testing and
interface design were presented, followed by discussions of
future research directions
The Properties of the Radio-Selected 1Jy Sample of BL Lacertae Objects
We present new optical and near-IR spectroscopy as well as new high dynamic
range, arcsecond-resolution VLA radio maps of BL Lacs from the complete
radio-selected "1 Jansky" (1Jy) sample (RBLs) for which such data were not
previously available. Unlike BL Lacs from the complete X-ray-selected Einstein
Medium Sensitivity Survey (EMSS) sample (XBLs), most RBLs possess weak but
moderately luminous emission lines. And whereas nearly all XBLs have extended
power levels consistent with FR-1s, more than half of the RBLs have extended
radio power levels too luminous to be beamed FR-1 radio galaxies. In fact, we
find evidence for and examples of three distinct mechanisms for creating the BL
Lac phenomenon in the 1Jy sample: beamed FR-1s, beamed FR-2s and possibly a few
gravitationally-lensed quasars. The v/v_max determined for the 1Jy sample is
0.614+/-0.047, which is markedly different from the negative evolution seen in
the EMSS and other XBL samples. A correlation between logarithmic X-ray to
radio flux ratio and v/v_max is observed across the EMSS and 1Jy samples, from
negative evolution in the more extreme XBLs to positive evolution in the more
extreme RBLs. There is evidence that the selection criteria chosen by Stickel
et al. eliminates some BL Lac objects from the 1Jy sample, although how many is
unknown. And several objects currently in the sample have exhibited strong
emission lines in one or more epochs, suggesting they should be reclassified as
FSRQs. However these selection effects cannot account for the observed
discrepancy in XBL and RBL properties. From these observational properties we
conclude that RBLs and XBLs cannot be related by viewing angle alone, and that
RBLs are more closely related to FSRQs.Comment: 29 pages, 47 figures, accepted A
The Deep X-ray Radio Blazar Survey (DXRBS). I. Methods and First Results
We have undertaken a survey of archived, pointed ROSAT PSPC data for blazars
by correlating the ROSAT WGACAT database with several publicly available radio
catalogs, restricting our candidate list to serendipitous flat radio spectrum
sources (alpha_r <= 0.70). Here we discuss our survey methods, identification
procedure and first results. Our survey is found to be ~ 95% efficient at
finding flat-spectrum radio-loud quasars (FSRQs, 59 of our first 85 IDs) and BL
Lacertae objects (22 of our first 85 IDs), a figure which is comparable to or
greater than that achieved by other radio and X-ray survey techniques.
The identifications presented here show that all previous samples of blazars
(even when taken together) did not representatively survey the blazar
population, missing critical regions of (L_X,L_R) parameter space within which
large fractions of the blazar population lie. Particularly important is the
identification of a large population of FSRQs (>~ 25% of DXRBS FSRQs) with
ratios of X-ray to radio luminosity >~ 10^-6 (alpha_rx <~ 0.78). In addition,
due to our greater sensitivity, DXRBS has already more than doubled the number
of FSRQs in complete samples with 5 GHz (radio) luminosities between 10^31.5
and 10^33.5 erg/s/Hz and fills in the region of parameter space between X-ray
selected and radio-selected samples of BL Lacs. DXRBS is the very first sample
to contain statistically significant numbers of blazars at low luminosities,
approaching what should be the lower end of the FSRQ luminosity function.Comment: 34 pages, 7 figures, 6 tables, LaTeX file, uses aaspp4.sty. To appear
in the Astronomical Journa
Why Robots Should Be Social: Enhancing Machine Learning through Social Human-Robot Interaction.
Social learning is a powerful method for cultural propagation of knowledge and skills relying on a complex interplay of learning strategies, social ecology and the human propensity for both learning and tutoring. Social learning has the potential to be an equally potent learning strategy for artificial systems and robots in specific. However, given the complexity and unstructured nature of social learning, implementing social machine learning proves to be a challenging problem. We study one particular aspect of social machine learning: that of offering social cues during the learning interaction. Specifically, we study whether people are sensitive to social cues offered by a learning robot, in a similar way to children's social bids for tutoring. We use a child-like social robot and a task in which the robot has to learn the meaning of words. For this a simple turn-based interaction is used, based on language games. Two conditions are tested: one in which the robot uses social means to invite a human teacher to provide information based on what the robot requires to fill gaps in its knowledge (i.e. expression of a learning preference); the other in which the robot does not provide social cues to communicate a learning preference. We observe that conveying a learning preference through the use of social cues results in better and faster learning by the robot. People also seem to form a "mental model" of the robot, tailoring the tutoring to the robot's performance as opposed to using simply random teaching. In addition, the social learning shows a clear gender effect with female participants being responsive to the robot's bids, while male teachers appear to be less receptive. This work shows how additional social cues in social machine learning can result in people offering better quality learning input to artificial systems, resulting in improved learning performance
MicroRNA Genes Derived from Repetitive Elements and Expanded by Segmental Duplication Events in Mammalian Genomes
MicroRNAs (miRNAs) are a class of small noncoding RNAs that regulate gene
expression by targeting mRNAs for translation repression or mRNA degradation.
Many miRNAs are being discovered and studied, but in most cases their origin,
evolution and function remain unclear. Here, we characterized miRNAs derived
from repetitive elements and miRNA families expanded by segmental duplication
events in the human, rhesus and mouse genomes. We applied a comparative genomics
approach combined with identifying miRNA paralogs in segmental duplication pair
data in a genome-wide study to identify new homologs of human miRNAs in the
rhesus and mouse genomes. Interestingly, using segmental duplication pair data,
we provided credible computational evidence that two miRNA genes are located in
the pseudoautosomal region of the human Y chromosome. We characterized all the
miRNAs whether they were derived from repetitive elements or not and identified
significant differences between the repeat-related miRNAs (RrmiRs) and
non-repeat-derived miRNAs in (1) their location in protein-coding and intergenic
regions in genomes, (2) the minimum free energy of their hairpin structures, and
(3) their conservation in vertebrate genomes. We found some lineage-specific
RrmiR families and three lineage-specific expansion families, and provided
evidence indicating that some RrmiR families formed and expanded during
evolutionary segmental duplication events. We also provided computational and
experimental evidence for the functions of the conservative RrmiR families in
the three species. Together, our results indicate that repetitive elements
contribute to the origin of miRNAs, and large segmental duplication events could
prompt the expansion of some miRNA families, including RrmiR families. Our study
is a valuable contribution to the knowledge of evolution and function of
non-coding region in genome
Análisis sistémico de las externalidades del mercado de bioetanol
Trabajo de investigaciónEn Colombia a partir de la resolución 40108 de 2018, se aumentó el porcentaje de mezcla del combustibles llegando a un 10% (90% combustibles fósiles 10% biocombustibles), actualmente para suplir esta demanda, las productoras de bioetanol requieren emplear al 100% su capacidad instalada, mejorar sus prácticas de cultivo de caña de azúcar y hacer uso de nuevas hectáreas, por tanto, el presente trabajo de grado tiene como objetivo realizar un análisis sistémico de las externalidades del mercado de bioetanol.INTRODUCCIÓN
1. Formulación del trabajo
2. Marco referencial
3. Diagrama propuesto
4. Conclusiones generales
BibliografiaPregradoEconomist
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