1,762 research outputs found
Climate and soil factors influencing seedling recruitment of plant species used for dryland restoration
Land degradation affects 10–20% of drylands globally. Intensive land use and management, largescale disturbances such as extractive operations, and global climate change, have contributed to degradation of these systems worldwide. Restoring these damaged environments is critical to improving ecosystem services and functions, conserve biodiversity, and contribute to climate resilience, food security, and landscape sustainability. Here, we present a case study on plant species of the mining intensive semi-arid Pilbara region in Western Australia that examines the effects of climate and soil factors on the restoration of drylands. We analysed the effects of a range of rainfall and temperature scenarios and the use of alternative soil materials on seedling recruitment of key native plant species from this area. Experimental studies were conducted in controlled environment facilities where conditions simulated those found in the Pilbara. Soil from topsoil (T) stockpiles and waste materials (W) from an active mine site were mixed at different proportions (100% T, 100% W, and two mixes of topsoil and waste at 50 : 50 and 25 : 75 ratios) and used as growth media. Our results showed that seedling recruitment was highly dependent on soil moisture and emergence was generally higher in the topsoil, which had the highest available water content. In general, responses to the climate scenarios differed significantly among the native species which suggest that future climate scenarios of increasing drought might affect not only seedling recruitment but also diversity and structure of native plant communities. The use of waste materials from mining operations as growth media could be an alternative to the limited topsoil. However, in the early stages of plant establishment successful seedling recruitment can be challenging in the absence of water. These limitations could be overcome by using soil amendments but the cost associated to these solutions at large landscape scales needs to be assessed and proven to be economically feasible
Perinatal asphyxia: CNS development and deficits with delayed onset
Perinatal asphyxia constitutes a prototype of obstetric complications occurring when pulmonary
oxygenation is delayed or interrupted. The primary insult relates to the duration of the period
lacking oxygenation, leading to death if not re-established. Re-oxygenation leads to a secondary
insult, related to a cascade of biochemical events required for restoring proper function. Perinatal
asphyxia interferes with neonatal development, resulting in long-term deficits associated to mental
and neurological diseases with delayed clinical onset, by mechanisms not yet clarified.
In the experimental scenario, the effects observed long after perinatal asphyxia have been explained
by over expression of sentinel proteins, such as poly(ADP-ribose) polymerase-1 (PARP-1),
competing for NAD+ during re-oxygenation, leading to the idea that sentinel protein inhibition
constitutes a suitable therapeutic strategy. Asphyxia induces transcriptional activation of proinflammatory
factors, in tandem with PARP-1 overactivation, and pharmacologically induced
PARP-1 inhibition also down-regulates the expression of proinflammatory cytokines.
Nicotinamide has been proposed as a suitable PARP-1 inhibitor. Its effect has been studied in
an experimental model of global hypoxia in rats. In that model, the insult is induced by immersing
rat foetuses into a water bath for various periods of time. Following asphyxia, the pups are
delivered, treated, and nursed by surrogate dams, pending further experiments. Nicotinamide
rapidly distributes into the brain following systemic administration, reaching steady state
concentrations sufficient to inhibit PARP-1 activity for several hours, preventing several of the
long-term consequences of perinatal asphyxia, supporting the idea that it constitutes a lead for
exploring compounds with similar or better pharmacological profiles
Should COVID-19 Patients \u3e 75 Years be Ventilated? An Outcome Study.
Background
Elderly patients with COVID-19 disease are at increased risk for adverse outcomes. Current data regarding disease characteristics and outcomes in this population is limited. Aim
To delineate the adverse factors associated with outcomes of COVID- 19 patients ≥75 years of age. Design
Retrospective cohort study. Methods
Patients were classified into mild/moderate, severe/very severe, and critical disease (intubated) based on oxygen requirements. The primary outcome was in-hospital mortality. Results
355 patients aged ≥75 years hospitalized with COVID-19 between March 19th and April 25th, 2020 were included. Mean age was 84.3 years. One-third of the patients developed critical disease. Mean length of stay was 7.10 days. Vasopressors were required in 27%, with the highest frequency in the critical disease group (74.1%). Overall mortality was 57.2%, with a significant difference between severity groups (mild/moderate disease : 17.4%, severe/very severe disease : 71.3%, critical disease: 94.9%, p \u3c 0.001). Increased age, dementia, and severe/very severe and critical disease groups were each significantly associated with increased odds for mortality while diarrhea was associated with decreased odds for mortality (OR : 0.12, 95% CI : 0.02-0.60, p \u3c 0.05)]. None of the cardiovascular comorbidities were significantly associated with mortality. Conclusion
Age and dementia are associated with increased odds for mortality in patients ≥75 years of age hospitalized with COVID-19. Those who require intubation have the greatest odds for mortality. Diarrhea as a presenting symptom was associated with lower odds for mortality
Outcomes in Patients With COVID-19 Disease and High Oxygen Requirements.
Background
Approximately 19% of people infected with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) progress to severe or critical stages of the coronavirus disease 2019 (COVID-19) with a mortality rate exceeding 50%. We aimed to examine the characteristics, mortality rates, intubation rate, and length of stay (LOS) of patients hospitalized with COVID-19 disease with high oxygen requirements (critically ill). Methods
We conducted a retrospective analysis in a single center in Brooklyn, New York. Adult hospitalized patients with confirmed COVID-19 disease and high oxygen requirements were included. We performed multivariate logistic regression analyses for statistically significant variables to reduce any confounding. Results
A total of 398 patients were identified between March 19th and April 25th, 2020 who met the inclusion criteria, of which 247 (62.1%) required intubation. The overall mortality rate in our study was 57.3% (n = 228). The mean hospital LOS was 19.1 ± 17.4 days. Patients who survived to hospital discharge had a longer mean LOS compared to those who died during hospitalization (25.4 ± 22.03 days versus10.7 ± 1.74 days). In the multivariate analysis, increased age, intubation and increased lactate dehydrogenase (LDH) were each independently associated with increased odds of mortality. Diarrhea was associated with decreased mortality (OR 0.4; CI 0.16, 0.99). Obesity and use of vasopressors were each independently associated with increased intubation. Conclusions
In patients with COVID-19 disease and high oxygen requirements, advanced age, intubation, and higher LDH levels were associated with increased mortality, while diarrhea was associated with decreased mortality. Gender, diabetes, and hypertension did not have any association with mortality or length of hospital stay
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Cool stars in the Galactic center as seen by APOGEE : M giants, AGB stars, and supergiant stars and candidates
The Galactic center region, including the nuclear disk, has until recently been largely avoided in chemical census studies because of extreme extinction and stellar crowding. Large, near-IR spectroscopic surveys, such as the Apache Point Observatory Galactic Evolution Experiment (APOGEE), allow the measurement of metallicities in the inner region of our Galaxy. Making use of the latest APOGEE data release (DR16), we are able for the first time to study cool Asymptotic Giant branch (AGB) stars and supergiants in this region. The stellar parameters of five known AGB stars and one supergiant star (VR 5-7) show that their location is well above the tip of the red giant branch. We studied metallicities of 157 M giants situated within 150 pc of the Galactic center from observations obtained by the APOGEE survey with reliable stellar parameters from the APOGEE pipeline making use of the cool star grid down to 3200 K. Distances, interstellar extinction values, and radial velocities were checked to confirm that these stars are indeed situated in the Galactic center region. We detect a clear bimodal structure in the metallicity distribution function, with a dominant metal-rich peak of [Fe/H] ∼ +0.3 dex and a metal-poor peak around {Fe/H] = −0.5 dex, which is 0.2 dex poorer than Baade’s Window. The α-elements Mg, Si, Ca, and O show a similar trend to the Galactic bulge. The metal-poor component is enhanced in the α-elements, suggesting that this population could be associated with the classical bulge and a fast formation scenario. We find a clear signature of a rotating nuclear stellar disk and a significant fraction of high-velocity stars with vgal >  300 km s−1; the metal-rich stars show a much higher rotation velocity (∼200 km s−1) with respect to the metal-poor stars (∼140 km s−1). The chemical abundances as well as the metallicity distribution function suggest that the nuclear stellar disk and the nuclear star cluster show distinct chemical signatures and might be formed differently
Rotation Symmetry Spontaneous Breaking of Edge States in Zigzag Carbon Nanotubes
Analytical solutions of the edge states were obtained for the (N, 0) type
carbon nanotubes with distorted ending bonds. It was found that the edge states
are mixed via the distortion. The total energies for N=5 and N>=7 are lower in
the asymmetric configurations of ending bonds than those having axial rotation
symmetry. Thereby the symmetry is breaking spontaneously. The results imply
that the symmetry of electronic states at the apex depends on the occupation;
the electron density pattern at the apex could change dramatically and could be
controlled by applying an external field.Comment: 19 pages, 3 figure
Maintaining natural and traditional cultural green infrastructures across Europe: learning from historic and current landscape transformations
CONTEXT: Maintaining functional green infrastructures (GIs) require evidence-based knowledge about historic and current states and trends of representative land cover types. OBJECTIVES: We address: (1) the long-term loss and transformation of potential natural forest vegetation; (2) the effects of site productivity on permanent forest loss and emergence of traditional cultural landscapes; (3) the current management intensity; and (4) the social-ecological contexts conducive to GI maintenance. METHODS: We selected 16 case study regions, each with a local hotspot landscape, ranging from intact forest landscapes, via contiguous and fragmented forest covers, to severe forest loss. Quantitative open access data were used to estimate (i) the historic change and (ii) transformation of land covers, and (iii) compare the forest canopy loss from 2000 to 2018. Qualitative narratives about each hotspot landscape were analysed for similarities (iv). RESULTS: While the potential natural forest vegetation cover in the 16 case study regions had a mean of 86%, historically it has been reduced to 34%. Higher site productivity coincided with transformation to non-forest land covers. The mean annual forest canopy loss for 2000–2018 ranged from 0.01 to 1.08%. The 16 case studies represented five distinct social-ecological contexts (1) radical transformation of landscapes, (2) abuse of protected area concepts, (3) ancient cultural landscapes (4) multi-functional forests, and (5) intensive even-aged forest management, of which 1 and 4 was most common. CONCLUSIONS: GIs encompass both forest naturalness and traditional cultural landscapes. Our review of Pan-European regions and landscapes revealed similarities in seemingly different contexts, which can support knowledge production and learning about how to sustain GIs
Cervical, Anal and Oral HPV in an Adolescent Inner-City Health Clinic Providing Free Vaccinations
Published human papillomavirus (HPV) vaccine trials indicate efficacy is strongest for those naive to the vaccine-types. However, few high-risk young women have been followed and cervical HPV has been the predominant outcome measure.We collected cervical and anal swabs, as well as oral rinse specimens from 645 sexually active inner-city young females attending a large adolescent health-clinic in New York City that offers free care and HPV vaccination. Specimens were tested for HPV-DNA using a MY09/MY11-PCR system. Type-specific prevalence of HPV at each anatomic site was compared for individuals by vaccination dose using generalized estimating equation logistic regression models.The majority of subjects reported being of non-Caucasian (92%) and/or Hispanic ethnicity (61%). Median age was 18 years (range:14-20). All had practiced vaginal sex, a third (33%) practiced anal sex, and most (77%) had also engaged in oral sex. At enrollment, 21% had not received the vaccine and 51% had received three doses. Prevalent HPV infection at enrollment was detected in 54% of cervical, 42% of anal and 20% of oral specimens, with vaccine types present in 7%, 6% and 1% of specimens, respectively. Comparing prevalence for vaccine types, the detection of HPV in the cervix of vaccinated compared to unvaccinated adolescents was significantly reduced: HPV6/11 (odds ratio [OR] = 0.19, 95%CI:0.06-0.75), HPV16 (OR = 0.31, 95%CI:0.11-0.88) and HPV18 (OR = 0.14, 95%CI:0.03-0.75). For anal HPV, the risk of detecting vaccine types HPV6/11 (OR = 0.27, 95%CI:0.10-0.72) and HPV18(OR = 0.12, 95%CI:0.01-1.16) were significantly reduced for vaccinated adolescents however, the risk for HPV16 was not significantly decreased (OR = 0.63, 95%CI:0.18-2.20).HPV Prevalence is extremely high in inner-city female adolescents. Administration of the HPV vaccine reduced the risk for cervical HPV; however continued follow-up is required to assess the protection for HPV at all sites in young women with high exposure
Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector
A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV
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