637 research outputs found
Lianas Suppress Seedling Growth and Survival of 14 Tree Species in a Panamanian Tropical Forest
Lianas are a common plant growth form in tropical forests, where they compete intensely with trees, decreasing tree recruitment, growth, and survival. If the detrimental effects of lianas vary significantly with tree species identity, as is often assumed, then lianas may influence tree species diversity and community composition. Furthermore, recent studies have shown that liana abundance and biomass are increasing relative to trees in neotropical forests, which will likely magnify the detrimental effects of lianas and may ultimately alter tree species diversity, relative abundances, and community composition. Few studies, however, have tested the responses of multiple tree species to the presence of lianas in robust, wellâreplicated experiments. We tested the hypotheses that lianas reduce tree seedling growth and survival, and that the effect of lianas varies with tree species identity. We used a largeâscale liana removal experiment in Central Panama in which we planted 14 replicate seedlings of 14 different tree species that varied in shade tolerance in each of 16 80 Ă 80 m plots (eight lianaâremoval and eight unmanipulated controls; 3136 total seedlings). Over a nearly twoâyr period, we found that tree seedlings survived 75% more, grew 300% taller, and had twice the aboveground biomass in lianaâremoval plots than seedlings in control plots, consistent with strong competition between lianas and tree seedlings. There were no significant differences in the response of tree species to liana competition (i.e., there was no species by treatment interaction), indicating that lianas had a similar negative effect on all 14 tree species. Furthermore, the effect of lianas did not vary with tree species shade tolerance classification, suggesting that the liana effect was not solely based on light. Based on these findings, recently observed increases in liana abundance in neotropical forests will substantially reduce tree regeneration, but will not significantly alter tropical tree species diversity, relative abundance, or community composition
Dual cholinergic signals regulate daily migration of hematopoietic stem cells and leukocytes.
Hematopoietic stem and progenitor cells (HSPCs) and leukocytes circulate between the bone marrow (BM) and peripheral blood following circadian oscillations. Autonomic sympathetic noradrenergic signals have been shown to regulate HSPC and leukocyte trafficking, but the role of the cholinergic branch has remained unexplored. We have investigated the role of the cholinergic nervous system in the regulation of day/night traffic of HSPCs and leukocytes in mice. We show here that the autonomic cholinergic nervous system (including parasympathetic and sympathetic) dually regulates daily migration of HSPCs and leukocytes. At night, central parasympathetic cholinergic signals dampen sympathetic noradrenergic tone and decrease BM egress of HSPCs and leukocytes. However, during the daytime, derepressed sympathetic noradrenergic activity causes predominant BM egress of HSPCs and leukocytes via ÎČ3-adrenergic receptor. This egress is locally supported by light-triggered sympathetic cholinergic activity, which inhibits BM vascular cell adhesion and homing. In summary, central (parasympathetic) and local (sympathetic) cholinergic signals regulate day/night oscillations of circulating HSPCs and leukocytes. This study shows how both branches of the autonomic nervous system cooperate to orchestrate daily traffic of HSPCs and leukocytes
Spectral determination of the colour and vertical structure of dark spots in Neptune's atmosphere
Previous observations of dark vortices in Neptune's atmosphere, such as
Voyager-2's Great Dark Spot, have been made in only a few, broad-wavelength
channels, which has hampered efforts to pinpoint their pressure level and what
makes them dark. Here, we present Very Large Telescope (Chile) MUSE
spectrometer observations of Hubble Space Telescope's NDS-2018 dark spot, made
in 2019. These medium-resolution 475 - 933 nm reflection spectra allow us to
show that dark spots are caused by a darkening at short wavelengths (< 700 nm)
of a deep ~5-bar aerosol layer, which we suggest is the HS condensation
layer. A deep bright spot, named DBS-2019, is also visible on the edge of
NDS-2018, whose spectral signature is consistent with a brightening of the same
5-bar layer at longer wavelengths (> 700 nm). This bright feature is much
deeper than previously studied dark spot companion clouds and may be connected
with the circulation that generates and sustains such spots.Comment: 1 table. 3 figures. Nature Astronomy (2023
Spectral determination of the colour and vertical structure of dark spots in Neptuneâs atmosphere
Previous observations of dark vortices in Neptuneâs atmosphere, such as Voyager 2âs Great Dark Spot (1989), have been made in only a few broad-wavelength channels, hampering efforts to determine these vorticesâ pressure levels and darkening processes. We analyse spectroscopic observations of a dark spot on Neptune identified by the Hubble Space Telescope as NDS-2018; the spectral observations were made in 2019 by the Multi Unit Spectroscopic Explorer (MUSE) of the Very Large Telescope (Chile). The MUSE medium-resolution 475â933ânm reflection spectra allow us to show that dark spots are caused by darkening at short wavelengths (700ânm). This bright feature is much deeper than previously studied dark-spot companion clouds and may be connected with the circulation that generates and sustains such spots
ALMA Long Baseline Observations of the Strongly Lensed Submillimeter Galaxy HATLAS J090311.6+003906 at z=3.042
We present initial results of very high resolution Atacama Large
Millimeter/submillimeter Array (ALMA) observations of the =3.042
gravitationally lensed galaxy HATLAS J090311.6+003906 (SDP.81). These
observations were carried out using a very extended configuration as part of
Science Verification for the 2014 ALMA Long Baseline Campaign, with baselines
of up to 15 km. We present continuum imaging at 151, 236 and 290 GHz, at
unprecedented angular resolutions as fine as 23 milliarcseconds (mas),
corresponding to an un-magnified spatial scale of ~180 pc at z=3.042. The ALMA
images clearly show two main gravitational arc components of an Einstein ring,
with emission tracing a radius of ~1.5". We also present imaging of CO(10-9),
CO(8-7), CO(5-4) and H2O line emission. The CO emission, at an angular
resolution of ~170 mas, is found to broadly trace the gravitational arc
structures but with differing morphologies between the CO transitions and
compared to the dust continuum. Our detection of H2O line emission, using only
the shortest baselines, provides the most resolved detection to date of thermal
H2O emission in an extragalactic source. The ALMA continuum and spectral line
fluxes are consistent with previous Plateau de Bure Interferometer and
Submillimeter Array observations despite the impressive increase in angular
resolution. Finally, we detect weak unresolved continuum emission from a
position that is spatially coincident with the center of the lens, with a
spectral index that is consistent with emission from the core of the foreground
lensing galaxy.Comment: 9 pages, 5 figures and 3 tables, accepted for publication in the
Astrophysical Journal Letter
A novel HPV 16 L1-based chimeric virus-like particle containing E6 and E7 seroreactive epitopes permits highly specific detection of antibodies in patients with CIN 1 and HPV-16 infection
<p>Abstract</p> <p>Background</p> <p>The presence of IgG antibodies to HPV-16 L1-virus like particles (VLPs) in serum has been reported as a result of persistent exposure to the virus and as a marker of disease progression. However, detection of VLP-specific antibodies in sera does not always indicate a malignant lesion as positive results may also be due to a nonmalignant viral infection. Furthermore, malignant lesions are associated with an increased antibody titer for E6 and E7 proteins. The aim of this study was to develop an ELISA using a novel chimeric virus-like particle (cVLP) encoding an L1 protein fused with a string of HPV-16 E6 and E7 seroreactive epitopes to its C-terminus to be used for detection of HPV-16 specific antibodies in patients with cervical intraepithelial lesion grade 1 (CIN 1).</p> <p>Results</p> <p>The sera of 30 patients with CIN 1 who also tested positive for HPV-16 DNA and of 30 age-matched normal donors negative for HPV infection were tested for the presence of IgG antibodies specific for either VLP-L1 (HPV-16 L1), gVLP (derived from Gardasil), or cVLP by ELISA. The cVLP-reactive sera yielded two distinct groups of results: (H) reactivity levels that presented very strong cVLP-specific titers, and (L) reactivity levels with significantly lower titers similar to those obtained with VLP-L1 and gVLP antigens. Additionally, the sera that presented the higher cVLP titers closely matched those that had significantly stronger reactivity to E6 and E7 epitopes. Interestingly, the samples with the highest titers corresponded to patients with the higher numbers of sexual partners and pregnancies. On the other hand only 4 out of the 12 sera that harbored antibodies with VLP neutralizing ability corresponded to the group with high cVLP antibody titers.</p> <p>Conclusion</p> <p>We report for the first time that chimeric particles containing HPV-16 L1 protein fused with E6 and E7 seroreactive epitopes enable much better detection of IgG antibodies in the sera of CIN 1 patients positive for HPV-16 infection than those obtained with VLPs containing only the HPV-16 L1 protein. We also found that the sera with higher cVLP antibody titers corresponded to patients with more sexual partners and pregnancies, and not always with to those with a high neutralizing activity. This novel assay could help in the development of a tool to evaluate cervical cancer risk.</p
Latitudinal Variations in Methane Abundance, Aerosol Opacity and Aerosol Scattering Efficiency in Neptune's Atmosphere Determined From VLT/MUSE
Spectral observations of Neptune made in 2019 with the Multi Unit Spectroscopic Explorer (MUSE) instrument at the Very Large Telescope (VLT) in Chile have been analyzed to determine the spatial variation of aerosol scattering properties and methane abundance in Neptune's atmosphere. The darkening of the South Polar Wave at âŒ60°S, and dark spots such as the Voyager 2 Great Dark Spot is concluded to be due to a spectrally dependent darkening (λ 650 nm. We find the properties of an overlying methane/haze aerosol layer at âŒ2 bar are, to first-order, invariant with latitude, while variations in the opacity of an upper tropospheric haze layer reproduce the observed reflectivity at methane-absorbing wavelengths, with higher abundances found at the equator and also in a narrow âzoneâ at 80°S. Finally, we find the mean abundance of methane below its condensation level to be 6%â7% at the equator reducing to âŒ3% south of âŒ25°S, although the absolute abundances are model dependent.We are grateful to the United Kingdom Science and Technology Facilities Council for funding this research (Irwin: ST/S000461/1, Teanby: ST/R000980/1). Glenn Orton was supported by funding to the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). Leigh Fletcher and Mike Roman were supported by a European Research Council Consolidator Grant (under the European Union's Horizon 2020 research and innovation programme, grant agreement no. 723890) at the University of Leicester. Santiago PĂ©rez-Hoyos and Agustin SĂĄnchez-Lavega are supported by the Spanish project PID2019-109467GB-I00 (MINECO/FEDER, UE), Elkartek21/87 KK-2021/00061 and Grupos Gobierno Vasco IT-1742-22
ICTON 2018
ProducciĂłn CientĂficaA genetic algorithm is proposed to map virtual network functions in computing resources over 5G networks with an optical backhauling system. The algorithm outperforms other proposals in terms of blocking ratio and active CPU cores utilization.Ministerio de EconomĂa, Industria y Competitividad (Projects TEC2014- 53071-C3 -2-P, TEC2017-84423- C3 -1-P, TEC2015-71932- REDT)Ministerio de EducaciĂłn, Cultura y Deporte (Proyects BES -2015-074514 and FPU14/04227
The Antioxidant Potential of the Mediterranean Diet in Patients at High Cardiovascular Risk: An In-Depth Review of the PREDIMED
Cardiovascular disease (CVD) is the leading global cause of death. Diet is known to be important in the prevention of CVD. The PREDIMED trial tested a relatively low-fat diet versus a high-fat Mediterranean diet (MedDiet) for the primary prevention of CVD. The resulting reduction of the CV composite outcome resulted in a paradigm shift in CV nutrition. Though many dietary factors likely contributed to this effect, this review focuses on the influence of the MedDiet on endogenous antioxidant systems and the effect of dietary polyphenols. Subgroup analysis of the PREDIMED trial revealed increased endogenous antioxidant and decreased pro-oxidant activity in the MedDiet groups. Moreover, higher polyphenol intake was associated with lower incidence of the primary outcome, overall mortality, blood pressure, inflammatory biomarkers, onset of new-onset type 2 diabetes mellitus (T2DM), and obesity. This suggests that polyphenols likely contributed to the lower incidence of the primary event in the MedDiet groups. In this article, we summarize the potential benefits of polyphenols found in the MedDiet, specifically the PREDIMED cohort. We also discuss the need for further research to confirm and expand the findings of the PREDIMED in a non-Mediterranean population and to determine the exact mechanisms of action of polyphenols
Recommended from our members
Demonstration of the event identification capabilities of the NEXT-White detector
In experiments searching for neutrinoless double-beta decay, the possibility of identifying the two emitted electrons is a powerful tool in rejecting background events and therefore improving the overall sensitivity of the experiment. In this paper we present the first measurement of the efficiency of a cut based on the different event signatures of double and single electron tracks, using the data of the NEXT-White detector, the first detector of the NEXT experiment operating underground. Using a 228Th calibration source to produce signal-like and background-like events with energies near 1.6 MeV, a signal efficiency of 71.6 ± 1.5 stat± 0.3 sys% for a background acceptance of 20.6 ± 0.4 stat± 0.3 sys% is found, in good agreement with Monte Carlo simulations. An extrapolation to the energy region of the neutrinoless double beta decay by means of Monte Carlo simulations is also carried out, and the results obtained show an improvement in background rejection over those obtained at lower energies. [Figure not available: see fulltext.
- âŠ