303 research outputs found
An analysis of the evolving comoving number density of galaxies in hydrodynamical simulations
The cumulative comoving number-density of galaxies as a function of stellar
mass or central velocity dispersion is commonly used to link galaxy populations
across different epochs. By assuming that galaxies preserve their
number-density in time, one can infer the evolution of their properties, such
as masses, sizes, and morphologies. However, this assumption does not hold in
the presence of galaxy mergers or when rank ordering is broken owing to
variable stellar growth rates. We present an analysis of the evolving comoving
number density of galaxy populations found in the Illustris cosmological
hydrodynamical simulation focused on the redshift range . Our
primary results are as follows: 1) The inferred average stellar mass evolution
obtained via a constant comoving number density assumption is systematically
biased compared to the merger tree results at the factor of 2(4) level
when tracking galaxies from redshift out to redshift ; 2) The
median number density evolution for galaxy populations tracked forward in time
is shallower than for galaxy populations tracked backward in time; 3) A similar
evolution in the median number density of tracked galaxy populations is found
regardless of whether number density is assigned via stellar mass, stellar
velocity dispersion, or dark matter halo mass; 4) Explicit tracking reveals a
large diversity in galaxies' assembly histories that cannot be captured by
constant number-density analyses; 5) The significant scatter in galaxy linking
methods is only marginally reduced by considering a number of additional
physical and observable galaxy properties as realized in our simulation. We
provide fits for the forward and backward median evolution in stellar mass and
number density and discuss implications of our analysis for interpreting
multi-epoch galaxy property observations.Comment: 18 pages, 11 figures, submitted to MNRAS, comments welcom
Superpulsed low-level laser therapy protects skeletal muscle of mdx mice against damage, inflammation and morphological changes delaying dystrophy progression.
Aim: To evaluate the effects of preventive treatment with low-level laser therapy (LLLT) on progression of dystrophy in mdx mice. Methods: Ten animals were randomly divided into 2 experimental groups treated with superpulsed LLLT (904 nm, 15 mW, 700 Hz, 1 J) or placebo-LLLT at one point overlying the tibialis anterior muscle (bilaterally) 5 times per week for 14 weeks (from 6th to 20th week of age). Morphological changes, creatine kinase (CK) activity and mRNA gene expression were assessed in animals at 20th week of age. Results: Animals treated with LLLT showed very few morphological changes in skeletal muscle, with less atrophy and fibrosis than animals treated with placebo-LLLT. CK was significantly lower (p = 0.0203) in animals treated with LLLT (864.70 U.l−1, SEM 226.10) than placebo (1708.00 U.l−1, SEM 184.60). mRNA gene expression of inflammatory markers was significantly decreased by treatment with LLLT (p<0.05): TNF-α (placebo-control = 0.51 µg/µl [SEM 0.12], - LLLT = 0.048 µg/µl [SEM 0.01]), IL-1β (placebo-control = 2.292 µg/µl [SEM 0.74], - LLLT = 0.12 µg/µl [SEM 0.03]), IL-6 (placebo-control = 3.946 µg/µl [SEM 0.98], - LLLT = 0.854 µg/µl [SEM 0.33]), IL-10 (placebo-control = 1.116 µg/µl [SEM 0.22], - LLLT = 0.352 µg/µl [SEM 0.15]), and COX-2 (placebo-control = 4.984 µg/µl [SEM 1.18], LLLT = 1.470 µg/µl [SEM 0.73]). Conclusion: Irradiation of superpulsed LLLT on successive days five times per week for 14 weeks decreased morphological changes, skeletal muscle damage and inflammation in mdx mice. This indicates that LLLT has potential to decrease progression of Duchenne muscular dystrophy
Hertz-linewidth semiconductor lasers using CMOS-ready ultra-high- microresonators
Driven by narrow-linewidth bench-top lasers, coherent optical systems
spanning optical communications, metrology and sensing provide unrivalled
performance. To transfer these capabilities from the laboratory to the real
world, a key missing ingredient is a mass-produced integrated laser with
superior coherence. Here, we bridge conventional semiconductor lasers and
coherent optical systems using CMOS-foundry-fabricated microresonators with
record high factor over 260 million and finesse over 42,000. Five
orders-of-magnitude noise reduction in the pump laser is demonstrated, and for
the first time, fundamental noise below 1 Hz Hz is achieved in an
electrically-pumped integrated laser. Moreover, the same configuration is shown
to relieve dispersion requirements for microcomb generation that have
handicapped certain nonlinear platforms. The simultaneous realization of
record-high factor, highly coherent lasers and frequency combs using
foundry-based technologies paves the way for volume manufacturing of a wide
range of coherent optical systems.Comment: 19 pages, 11 figure
Stock market investors' use of stop losses and the disposition effect
The disposition effect is an investment bias where investors hold stocks at a loss longer than stocks at a gain. This bias is associated with poorer investment performance and exhibited to a greater extent by investors with less experience and less sophistication. A method of managing susceptibility to the bias is through use of stop losses. Using the trading records of UK stock market individual investors from 2006 to 2009, this paper shows that stop losses used as part of investment decisions are an effective tool for inoculating against the disposition effect. We also show that investors who use stop losses have less experience and that, when not using stop losses, these investors are more reluctant to realise losses than other investors
Varicella Zoster Virus in Saliva of Patients With Herpes Zoster
Background. VZV DNA is present in saliva of healthy astronauts and patients with Ramsay Hunt syndrome (geniculate zoster). We hypothesized that a prospective analysis of patients with zoster would detect VZV in saliva independent of zoster location. Methods. We treated 54 patients with valacyclovir. On the first treatment day, 7- and 14-days later, pain was scored and saliva examined for VZV DNA. Saliva from six subjects with chronic pain and 14 healthy subjects was similarly studied. Results. Follow-up data was available for 50/54 patients. Pain decreased in 43/50 (86 percent), disappeared in 37 (74 percent), recurred after disappearing in three (6 percent) and increased in four (8 percent). VZV DNA was found in every patient the day treatment was started, decreased in 47/50 (94 percent), transiently increased in three (6 percent) before decreasing, increased in two (4 percent) and disappeared in 41 (82 percent). There was a positive correlation between the presence of VZV DNA and pain, as well as between the VZV DNA copy number and pain (P<0.0005). Saliva of two patients was cultured, and infectious VZV was isolated from one. VZV DNA was present in one patient before rash and in four patients after pain resolved, and not in any control subjects. Conclusion. VZV DNA is present in saliva of zoster patients
Dengue Outbreak Response During COVID-19 Pandemic, Key Largo, Florida, USA, 2020
We report a dengue outbreak in Key Largo, Florida, USA, from February through August 2020, during the COVID-19 pandemic. Successful community engagement resulted in 61% of case-patients self-reporting. We also describe COVID-19 pandemic effects on the dengue outbreak investigation and the need to increase clinician awareness of dengue testing recommendations
Insights into the pathogenesis of ulcerative colitis from a murine model of stasis-induced dysbiosis, colonic metaplasia, and genetic susceptibility
Author Posting. © The Author(s), 2016. This is the author's version of the work. It is posted here by permission of American Physiological Society for personal use, not for redistribution. The definitive version was published in American
Journal of Physiology-Gastrointestinal and Liver Physiology 310 (2016): G973-G988, doi:10.1152/ajpgi.00017.2016.Gut dysbiosis, host genetics, and environmental triggers are implicated as causative factors in
inflammatory bowel disease (IBD), yet mechanistic insights are lacking. Longitudinal analysis of
ulcerative colitis patients following total colectomy with ileal anal anastomosis (IPAA) where
>50% develop pouchitis, offers a unique setting to examine cause vs. effect. To recapitulate
human IPAA, we employed a mouse model of surgically created blind self-filling (SFL) and self-
emptying (SEL) ileal loops using wild-type (WT), IL-10 KO (IL10), and TLR4 KO (T4), and
IL10/T4 double KO mice. After 5 weeks, loop histology, host gene/protein expression, and
bacterial 16s rRNA profiles were examined. SFL exhibit fecal stasis due to directional motility
oriented towards the loop end, whereas SEL remain empty. In wild type mice, SFL, but not SEL,
develop pouch-like microbial communities without accompanying active inflammation. However,
in genetically susceptible IL-10-/- deficient mice, SFL, but not SEL, exhibit severe inflammation
and mucosal transcriptomes resembling human pouchitis. The inflammation associated with IL-
10-/- required TLR4, as animals lacking both pathways displayed little disease. Furthermore,
germ-free IL10-/- mice conventionalized with SFL, but not SEL, microbiota populations develop
severe colitis. These data support essential roles of stasis-induced, colon-like microbiota, TLR4-
mediated colonic metaplasia, and genetic susceptibility in the development of pouchitis and
possibly UC. However, these factors by themselves are not sufficient. Similarities between this
model and human UC/pouchitis provide opportunities for gaining insights into the mechanistic
basis of IBD and for identification of targets for novel preventative and therapeutic interventions.NIDDK DK42086 (DDRCC), UH3 DK083993, Leona and Harry
Helmsley Trust (SHARE), R37 DK47722, T32 DK07074, F32 DK105728, Gastrointestinal
Research Foundation of Chicago, Peter and Carol Goldman Family Research grant.2017-06-0
Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.
Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology
Reinvigorating the sustainable development research agenda: the role of the sustainable development goals (SDG)
© 2017 Informa UK Limited, trading as Taylor & Francis Group. The United Nations Sustainable Development Goals (UN SDGs) contain a set of 17 measures to foster sustainable development across many areas. It offers a good opportunity to reinvigorate sustainable development research for two main reasons. First, it comprises many areas of SD research, which have become mainstream thanks to the UN SDGs. Second, the fact that the UN and its member countries have committed to attaining SDGs by 2030 has added a sense of urgency to the need to perform quality research on SD on the one hand, and reiterates the need to use the results of this research on the other. Even though the basic concept of sustainability goes back many centuries, it has only recently appeared on the international political agenda. This is partly due to an awakening of the fact that the human ecological pressure on the planet is still much larger than what nature can renew or compensate for. Based on this state of affairs, this paper presents an outline of the process leading to the agreement on the UN SDGs, and looks at some of the ecological aspects as a result of continued pressure of human activities on natural resources. Furthermore, a set of research needs is proposed–also based holistically on updated research trends–discussing the degree of urgency of some measures and explaining why the UN SDGs need to be accorded greater priority in international sustainable development research efforts
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