11,166 research outputs found
Design parameters and color CRT display design
This report considers a number of the principal variables worthy of inclusion
in any attempt to apply color coding to CRT display design.http://archive.org/details/designparameters00neilN
Trade-offs between personal immunity and reproduction in the burying beetle, N. vespilloides
We know that parental investment and immune investment are costly processes, but it is unclear which trait will be prioritised when both may be required. Here we address this question using the burying beetle Nicrophorus vespilloides, carrion breeders that exhibit biparental care of young. Our results show that immunosuppression occurs during provision of parental care. We measured Phenoloxidase (PO) on Day 1-8 of the breeding bout and results show a clear decrease in PO immediately from presentation of the breeding resource onwards. Having established baseline immune investment during breeding we then manipulated immune investment at different times by applying a wounding challenge. Beetles were wounded prior to and during the parental care period and reproductive investment quantified. Different effects on reproductive output occur depending on the timing of wounding. Challenging the immune system with wounding prior to breeding does not affect reproductive output and subsequent Lifetime Reproductive Success (LRS). LRS is also unaffected by applying an immune elicitor prior to breeding, though different arms of the immune system are up/downregulated, perhaps indicating a trade-off between cellular and humoral immunity. In contrast, wounding during breeding reduces reproductive output and to the greatest extent if the challenge is applied early in the breeding bout. Despite being immunosuppressed, breeding beetles can still respond to wounding by increasing PO, albeit not to pre-breeding levels. This upregulation of PO during breeding may affect parental investment, resulting in a reduction in reproductive output. The potential role of juvenile hormone in controlling this trade-off is discussed
Characterizing the Galactic Gravitational Wave Background with LISA
We present a Monte Carlo simulation for the response of the Laser
Interferometer Space Antenna (LISA) to the galactic gravitational wave
background. The simulated data streams are used to estimate the number and type
of binary systems that will be individually resolved in a 1-year power
spectrum. We find that the background is highly non-Gaussian due to the
presence of individual bright sources, but once these sources are identified
and removed, the remaining signal is Gaussian. We also present a new estimate
of the confusion noise caused by unresolved sources that improves on earlier
estimates.Comment: 32 pages, 14 figures. Version to appear in PR
Negative emotional reactivity as a marker of vulnerability in the development of borderline personality disorder symptoms
Negative emotionality is a distinguishing feature of borderline personality disorder (BPD). However, this person-level characteristic has not been examined as a marker of vulnerability in the development of this disorder. The current study utilized a multi-method approach to examine the interplay between negative emotional reactivity and cumulative exposure to family adversity on the development of BPD symptoms across three years (ages 16–18) in a diverse, at-risk sample of adolescent girls (N=113). A latent variable of negative emotional reactivity was created from multiple assessments at age 16: (1) self-report, (2) emotion ratings to stressors from ecological assessments across one week, and (3) observer-rated negative affectivity during a mother-daughter conflict discussion task. Exposure to family adversity was measured cumulatively between ages 5 and 16 from annual assessments of family poverty, single parent household, and difficult life circumstances. Results from latent growth curve models demonstrated a significant interaction between negative emotional reactivity and family adversity, such that exposure to adversity strengthened the association between negative emotional reactivity and BPD symptoms. Additionally, family adversity predicted increasing BPD symptoms during late adolescence. These findings highlight negative emotional reactivity as a marker of vulnerability that ultimately increases risk for the development of BPD symptoms
ECONOMIC, ENVIRONMENTAL AND ENERGY USE IMPLICATIONS OF SHORT-SEASON COTTON PRODUCTION: TEXAS LOWER RIO GRANDE VALLEY
Crop Production/Industries,
IR Monitoring of the Microquasar GRS 1915+105: Detection of Orbital and Superhump Signatures
We present the results of seven years of K-band monitoring of the low-mass
X-ray binary GRS 1915+105. Positive correlations between the infrared flux and
the X-ray flux and X-ray hardness are demonstrated. Analysis of the frequency
spectrum shows that the orbital period of the system is
days. The phase and amplitude of the orbital modulation suggests that the
modulation is due to the heating of the face of the secondary star. We also
report another periodic signature between 31.2 and 31.6 days, most likely due
to a superhump resonance. From the superhump period we then obtain a range on
the mass ratio of the system, .Comment: 16 pages, 6 figures; v2: minor change
Contamination of histology biopsy specimen - a potential source of error for surgeons: a case report
Tissue contamination is a common occurrence in pathology, but surgeons are relatively unaware of this. We present the case of a 45-year-old man with Barrett's oesophagus, in which the histology of routine biopsies of an asymptomatic patient, were reported as 'carcinoma in situ'. Further biopsies were taken over a three month period but showed no evidence of malignancy. Tissue contamination or 'cross over' was identified as the likely cause of the abnormal result. This case report highlights the importance of the correlation of the clinical and histopathological findings and tissue contamination should be considered when both of these findings are not consistent
Starburst-driven Starbursts in the Heart of Ultraluminous Infrared Galaxies
There is increasing evidence for the presence of blue super star clusters in
the central regions of ultraluminous infrared galaxies like Arp 220.
Ultraluminous galaxies are thought to be triggered by galaxy mergers, and it
has often been argued that these super star clusters may form during violent
collisions between gas clouds in the final phase of the mergers. We now
investigate another set of models which differ from previous ones in that the
formation of the super star clusters is linked directly to the very intense
starburst occurring at the very center of the galaxy. Firstly we show that a
scenario in which the super star clusters form in material compressed by shock
waves originating from the central starburst is implausible because the objects
so produced are much smaller than the observed star clusters in Arp 220. We
then investigate a scenario (based on the Shlosman-Noguchi model) in which the
infalling dense gas disk is unstable gravitationally and collapses to form
massive gaseous clumps. Since these clumps are exposed to the external high
pressure driven by the superwind (a blast wave driven by a collective effect of
a large number of supernovae in the very core of the galaxy), they can collapse
and then massive star formation may be induced in them. The objects produced in
this kind of collapse have properties consistent with those of the observed
super star clusters in the center of Arp 220.Comment: 13 pages, 1 figure, ApJ (Letters) in pres
Tests of Bayesian Model Selection Techniques for Gravitational Wave Astronomy
The analysis of gravitational wave data involves many model selection
problems. The most important example is the detection problem of selecting
between the data being consistent with instrument noise alone, or instrument
noise and a gravitational wave signal. The analysis of data from ground based
gravitational wave detectors is mostly conducted using classical statistics,
and methods such as the Neyman-Pearson criteria are used for model selection.
Future space based detectors, such as the \emph{Laser Interferometer Space
Antenna} (LISA), are expected to produced rich data streams containing the
signals from many millions of sources. Determining the number of sources that
are resolvable, and the most appropriate description of each source poses a
challenging model selection problem that may best be addressed in a Bayesian
framework. An important class of LISA sources are the millions of low-mass
binary systems within our own galaxy, tens of thousands of which will be
detectable. Not only are the number of sources unknown, but so are the number
of parameters required to model the waveforms. For example, a significant
subset of the resolvable galactic binaries will exhibit orbital frequency
evolution, while a smaller number will have measurable eccentricity. In the
Bayesian approach to model selection one needs to compute the Bayes factor
between competing models. Here we explore various methods for computing Bayes
factors in the context of determining which galactic binaries have measurable
frequency evolution. The methods explored include a Reverse Jump Markov Chain
Monte Carlo (RJMCMC) algorithm, Savage-Dickie density ratios, the Schwarz-Bayes
Information Criterion (BIC), and the Laplace approximation to the model
evidence. We find good agreement between all of the approaches.Comment: 11 pages, 6 figure
Link-space formalism for network analysis
We introduce the link-space formalism for analyzing network models with
degree-degree correlations. The formalism is based on a statistical description
of the fraction of links l_{i,j} connecting nodes of degrees i and j. To
demonstrate its use, we apply the framework to some pedagogical network models,
namely, random-attachment, Barabasi-Albert preferential attachment and the
classical Erdos and Renyi random graph. For these three models the link-space
matrix can be solved analytically. We apply the formalism to a simple
one-parameter growing network model whose numerical solution exemplifies the
effect of degree-degree correlations for the resulting degree distribution. We
also employ the formalism to derive the degree distributions of two very simple
network decay models, more specifically, that of random link deletion and
random node deletion. The formalism allows detailed analysis of the
correlations within networks and we also employ it to derive the form of a
perfectly non-assortative network for arbitrary degree distribution.Comment: This updated version has been expanded to include a number of new
results. 19 pages, 11 figures. Minor Typos correcte
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