Human activities, especially conversion and degradation of habitats, are causing global biodiversity declines. How local ecological assemblages are responding is less clear--a concern given their ...importance for many ecosystem functions and services. We analysed a terrestrial assemblage database of unprecedented geographic and taxonomic coverage to quantify local biodiversity responses to land use and related changes. Here we show that in the worst-affected habitats, these pressures reduce within-sample species richness by an average of 76.5%, total abundance by 39.5% and rarefaction-based richness by 40.3%. We estimate that, globally, these pressures have already slightly reduced average within-sample richness (by 13.6%), total abundance (10.7%) and rarefaction-based richness (8.1%), with changes showing marked spatial variation. Rapid further losses are predicted under a business-as-usual land-use scenario; within-sample richness is projected to fall by a further 3.4% globally by 2100, with losses concentrated in biodiverse but economically poor countries. Strong mitigation can deliver much more positive biodiversity changes (up to a 1.9% average increase) that are less strongly related to countries' socioeconomic status.
Time-dependent density functional theory calculations have been performed on acetophenone derivatives to explore the possibility of using charged functional groups as internal electric fields, the ...orientation of which can be altered to change photochemical behavior at will. Results demonstrate that nonconjugated charged groups can significantly alter, by up to −1.44 eV, the stabilities of excited states. Specifically, a nonconjugated negatively charged group in the para position will destabilize the nπ* and stabilize the ππ* transitions, while a positively charged group will do the opposite. These electrostatic effects can be tuned by moving these substituents into the meta and ortho positions. Through use of acids and bases, these charged groups can be switched on or off with pH, allowing for selective alteration of the energy levels and photochemical reactivity. Solvent effects are shown to attenuate the electric field effect with increasing dielectric permittivity; however electrostatic effects are shown to remain significant even in quite polar solvents. Using charged functional groups to deliver the position-dependent electrostatic (de)stabilization effects is therefore a potential route to improving the efficiency of desirable photochemical processes.
Habitat loss and degradation, driven largely by agricultural expansion and intensification, present the greatest immediate threat to biodiversity. Tropical forests harbour among the highest levels of ...terrestrial species diversity and are likely to experience rapid land-use change in the coming decades. Synthetic analyses of observed responses of species are useful for quantifying how land use affects biodiversity and for predicting outcomes under land-use scenarios. Previous applications of this approach have typically focused on individual taxonomic groups, analysing the average response of the whole community to changes in land use. Here, we incorporate quantitative remotely sensed data about habitats in, to our knowledge, the first worldwide synthetic analysis of how individual species in four major taxonomic groups—invertebrates, ‘herptiles’ (reptiles and amphibians), mammals and birds—respond to multiple human pressures in tropical and sub-tropical forests. We show significant independent impacts of land use, human vegetation offtake, forest cover and human population density on both occurrence and abundance of species, highlighting the value of analysing multiple explanatory variables simultaneously. Responses differ among the four groups considered, and—within birds and mammals—between habitat specialists and habitat generalists and between narrow-ranged and wide-ranged species.
A Catalog of Habitable Zone Exoplanets Hill, Michelle L.; Bott, Kimberly; Dalba, Paul A. ...
The Astronomical journal,
02/2023, Letnik:
165, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Abstract
The search for habitable planets has revealed many planets that can vary greatly from an Earth analog environment. These include highly eccentric orbits, giant planets, different bulk ...densities, relatively active stars, and evolved stars. This work catalogs all planets found to reside in the habitable zone (HZ) and provides HZ boundaries, orbit characterization, and the potential for spectroscopic follow-up observations. Demographics of the HZ planets are compared with a full catalog of exoplanets. Extreme planets within the HZ are highlighted, and how their unique properties may affect their potential habitability is discussed. Kepler-296 f is the most eccentric ≤2
R
⊕
planet that spends 100% of its orbit in the HZ. HD 106270 b and HD 38529 c are the most massive planets (≤13
M
J
) that orbit within the HZ, and are ideal targets for determining the properties of potential hosts of HZ exomoons. These planets, along with the others highlighted, will serve as special edge cases to the Earth-based scenario, and observations of these targets will help test the resilience of habitability outside the standard model. The most promising observational HZ target that is known to transit is GJ 414 A b. Of the transiting, ≤2
R
⊕
HZ planets, LHS 1140 b, TRAPPIST-1 d, and K2-3 d are the most favorable. Of the nontransiting HZ planets, HD 102365 b and 55 Cnc f are the most promising, and the best nontransiting candidates that have ≤2
R
⊕
are GJ 667 C c, Wolf 1061 c, Ross 508 b, Teegarden’s Star b, and Proxima Cen b.
The aim of this study was to determine whether an educational intervention was sufficient to decrease opioid prescribing after general surgical operations.
We recently analyzed opioid prescription ...and use for 5 common outpatient operations at our institution: partial mastectomy (PM), PM with sentinel lymph node biopsy (PM SLNB), laparoscopic cholecystectomy (LC), laparoscopic inguinal hernia repair (LIH), and open inguinal hernia repair (IH). We found that opioids were over-prescribed. We formulated guidelines for opioid prescribing that would halve the number of pills prescribed and also satisfy 80% of patients' opioid requirements.
We discussed our findings and opioid-prescribing guidelines with surgeons at our institution. We recommended that surgeons encourage patients to use a nonsteroidal anti-inflammatory drug (NSAID) and acetaminophen before using opioids. We then evaluated opioid prescriptions and use in 246 subsequent patients undergoing these same operations.
The mean number of opioid pills prescribed for each operation markedly decreased: PM 19.8 versus 5.1; PM SLNB 23.7 versus 9.6; LC 35.2 versus 19.4; LIH 33.8 versus 19.3, and IH 33.2 versus 18.3; all P < 0.0003. The total number of pills prescribed decreased by 53% when compared with the number that would have been prescribed before the educational intervention. Only 1 patient (0.4%) required a refill opioid prescription. Eighty-five percent of patients used either a NSAID or acetaminophen.
By defining postoperative opioid requirements through patient surveys and disseminating operation-specific guidelines for opioid prescribing to surgeons, we were able to decrease the number of opioids initially prescribed by more than half. Decreased initial opioid prescriptions did not result in increased opioid refill prescriptions.
To examine opioid prescribing patterns after general surgery procedures and to estimate an ideal number of pills to prescribe.
Diversion of prescription opioids is a major contributor to the rising ...mortality from opioid overdoses. Data to inform surgeons on the optimal dose of opioids to prescribe after common general surgical procedures is lacking.
We evaluated 642 patients undergoing 5 outpatient procedures: partial mastectomy (PM), partial mastectomy with sentinel lymph node biopsy (PM SLNB), laparoscopic cholecystectomy (LC), laparoscopic inguinal hernia repair (LIH), and open inguinal hernia repair (IH). Postoperative opioid prescriptions and refill data were tabulated. A phone survey was conducted to determine the number of opioid pills taken.
There was a wide variation in the number of opioid pills prescribed to patients undergoing the same operation. The median number (and range) prescribed were: PM 20 (0-50), PM SLNB 20 (0-60), LC 30 (0-100), LIH 30 (15-70), and IH 30 (15-120). Only 28% of the prescribed pills were taken. This percentage varied by operation: PM 15%, PM SLNB 25%, LC 33%, LIH 15%, and IH 31%. Less than 2% of patients obtained refills.We identified the number of pills that would fully supply the opioid needs of 80% of patients undergoing each operation: PM 5, PM SLNB 10, LC 15, LIH 15, and IH 15. If this number were prescribed, the number of opioid initially prescribed would be 43% of the actual number prescribed.
There is wide variability in opioid prescriptions for common general surgery procedures. In many cases excess pills are prescribed. Using our ideal number, surgeons can adequately treat postoperative pain and markedly decrease the number of opioids prescribed.
ABSTRACT The NASA Kepler mission ha s discovered thousands of new planetary candidates, many of which have been confirmed through follow-up observations. A primary goal of the mission is to determine ...the occurrence rate of terrestrial-size planets within the Habitable Zone (HZ) of their host stars. Here we provide a list of HZ exoplanet candidates from the Kepler Q1-Q17 Data Release 24 data-vetting process. This work was undertaken as part of the Kepler HZ Working Group. We use a variety of criteria regarding HZ boundaries and planetary sizes to produce complete lists of HZ candidates, including a catalog of 104 candidates within the optimistic HZ and 20 candidates with radii less than two Earth radii within the conservative HZ. We cross-match our HZ candidates with the stellar properties and confirmed planet properties from Data Release 25 to provide robust stellar parameters and candidate dispositions. We also include false-positive probabilities recently calculated by Morton et al. for each of the candidates within our catalogs to aid in their validation. Finally, we performed dynamical analysis simulations for multi-planet systems that contain candidates with radii less than two Earth radii as a step toward validation of those systems.
We present a detailed study of the faint Milky Way satellite Draco II (Dra II) from deep CFHT/MegaCam broad-band g and i photometry and narrow-band metallicity-sensitive CaHK observations, along with ...follow-up Keck II/DEIMOS multi-object spectroscopy. Forward modelling of the deep photometry allows us to refine the structural and photometric properties of Dra II: the distribution of stars in colour-magnitude space implies Dra II is old (13.5 ± 0.5 Gyr), very metal-poor, very faint (L_V = 180 ^{+124}_{-72} { L_⊙}), and at a distance d = 21.5 ± 0.4 { kpc}. The narrow-band, metallicity-sensitive CaHK Pristine photometry confirms this very low metallicity (Fe/H = -2.7 ± 0.1 dex). Even though our study benefits from a doubling of the spectroscopic sample size compared to previous investigations, the velocity dispersion of the system is still only marginally resolved (σ _{vr}< 5.9 { km s^{-1}} at the 95 per cent confidence level) and confirms that Dra II is a dynamically cold stellar system with a large recessional velocity (< vr> = -342.5^{+1.1}_{-1.2}{ km s^{-1}}). We further show that the spectroscopically confirmed members of Dra II have a mean proper motion of (μ _α ^*,μ _δ)=(1.26 ± 0.27,0.94 ± 0.28) { mas/yr} in the Gaia DR2 data, which translates to an orbit with a pericentre and an apocentre of 21.3 ^{+0.7}_{-1.0} and 153.8 ^{+56.7}_{-34.7} { kpc}, respectively. Taken altogether, these properties favour the scenario of Dra II being a potentially disrupting dwarf galaxy. The low-significance extra-tidal features we map around the satellite tentatively support this scenario.
The evolution of gaseous products is a feature common to several electrochemical processes, often resulting in bubbles adhering to the electrode's surface. Adherent bubbles reduce the electrode ...active area, and are therefore generally treated as electrochemically inert entities. Here, we show that this general assumption does not hold for gas bubbles masking anodes operating in water. By means of imaging electrochemiluminescent systems, and by studying the anisotropy of polymer growth around bubbles, we demonstrate that gas cavities adhering to an electrode surface initiate the oxidation of water-soluble species more effectively than electrode areas free of bubbles. The corona of a bubble accumulates hydroxide anions, unbalanced by cations, a phenomenon which causes the oxidation of hydroxide ions to hydroxyl radicals to occur at potentials at least 0.7 V below redox tabled values. The downhill shift of the hydroxide oxidation at the corona of the bubble is likely to be a general mechanism involved in the initiation of heterogeneous electrochemical reactions in water, and could be harnessed in chemical synthesis.
Most enveloped viruses rely on the host cell endoplasmic reticulum (ER) quality control (QC) machinery for proper folding of glycoproteins. The key ER α-glucosidases (α-Glu) I and II of the ERQC ...machinery are attractive targets for developing broad-spectrum antivirals. Iminosugars based on deoxynojirimycin have been extensively studied as ER α-glucosidase inhibitors; however, other glycomimetic compounds are less established. Accordingly, we synthesized a series of N-substituted derivatives of valiolamine, the iminosugar scaffold of type 2 diabetes drug voglibose. To understand the basis for up to 100,000-fold improved inhibitory potency, we determined high-resolution crystal structures of mouse ER α-GluII in complex with valiolamine and 10 derivatives. The structures revealed extensive interactions with all four α-GluII subsites. We further showed that N-substituted valiolamines were active against dengue virus and SARS-CoV-2 in vitro. This study introduces valiolamine-based inhibitors of the ERQC machinery as candidates for developing potential broad-spectrum therapeutics against the existing and emerging viruses.
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