The Falkland Islands’ palaeoecological response to millennial‐scale climate perturbations during the Pleistocene–Holocene transition: implications for future vegetation stability in the southern ocean islands

Oceanic island flora is vulnerable to future climate warming, which is likely to promote changes in vegetation composition, and invasion of non‐native species. Sub‐Antarctic islands are predicted to experience rapid warming during the next century; therefore, establishing trajectories of change in vegetation communities is essential for developing conservation strategies to preserve biological diversity. We present a Late‐glacial‐early Holocene (16 500–6450 cal a bp) palaeoecological record from Hooker's Point, Falkland Islands (Islas Malvinas), South Atlantic. This period spans the Pleistocene‐Holocene transition, providing insight into biological responses to abrupt climate change. Pollen and plant macrofossil records appear insensitive to climatic cooling during the Late‐glacial, but undergo rapid turnover in response to regional warming. The absence of trees throughout the Late‐glacial‐early Holocene enables the recognition of far‐travelled pollen from southern South America. The first occurrence of Nothofagus (southern beech) may reflect changes in the strength and/or position of the Southern Westerly Wind Belt during the Late‐glacial period. Peat inception and accumulation at Hooker's Point is likely to be promoted by the recalcitrant litter of wind‐adapted flora. This recalcitrant litter helps to explain widespread peatland development in a comparatively dry environment, and suggests that wind‐adapted peatlands can remain carbon sinks even under low precipitation regimes

Giant molecular filaments in the Milky Way II. The fourth Galactic quadrant

Context: Filamentary structures are common morphological features of the cold, molecular interstellar medium (ISM). Recent studies have discovered massive, hundred-parsec-scale filaments that may be connected to the large-scale, Galactic spiral arm structure. Addressing the nature of these giant molecular filaments (GMFs) requires a census of their occurrence and properties. Aims: We perform a systematic search of GMFs in the fourth Galactic quadrant and determine their basic physical properties. Methods: We identify GMFs based on their dust extinction signatures in the near- and mid-infrared and the velocity structure probed by 13CO line emission. We use the 13CO line emission and ATLASGAL dust emission data to estimate the total and dense gas masses of the GMFs. We combine our sample with an earlier sample from literature and study the Galactic environment of the GMFs. Results: We identify nine GMFs in the fourth Galactic quadrant: six in the Centaurus spiral arm and three in inter-arm regions. Combining this sample with an earlier study using the same identification criteria in the first Galactic quadrant results in 16 GMFs, nine of which are located within spiral arms. The GMFs have sizes of 80–160 pc and 13CO-derived masses between 5−90 × 104M⊙. Their dense gas mass fractions are between 1.5–37%, which is higher in the GMFs connected to spiral arms. We also compare the different GMF-identification methods and find that emission and extinction-based techniques overlap only partially, thereby highlighting the need to use both to achieve a complete census

A Spitzer Space Telescope far-infrared spectral atlas of compact sources in the Magellanic Clouds. I. The Large Magellanic Cloud

[abridged] We present 52-93 micron spectra obtained with Spitzer in the MIPS-SED mode, of a representative sample of luminous compact far-IR sources in the LMC. These include carbon stars, OH/IR AGB stars, post-AGB objects and PNe, RCrB-type star HV2671, OH/IR red supergiants WOHG064 and IRAS05280-6910, B[e] stars IRAS04530-6916, R66 and R126, Wolf-Rayet star Brey3a, Luminous Blue Variable R71, supernova remnant N49, a large number of young stellar objects, compact HII regions and molecular cores, and a background galaxy (z~0.175). We use the spectra to constrain the presence and temperature of cold dust and the excitation conditions and shocks within the neutral and ionized gas, in the circumstellar environments and interfaces with the surrounding ISM. Evolved stars, including LBV R71, lack cold dust except in some cases where we argue that this is swept-up ISM. This leads to an estimate of the duration of the prolific dust-producing phase ("superwind") of several thousand years for both RSGs and massive AGB stars, with a similar fractional mass loss experienced despite the different masses. We tentatively detect line emission from neutral oxygen in the extreme RSG WOHG064, with implications for the wind driving. In N49, the shock between the supernova ejecta and ISM is revealed by its strong [OI] 63-micron emission and possibly water vapour; we estimate that 0.2 Msun of ISM dust was swept up. Some of the compact HII regions display pronounced [OIII] 88-micron emission. The efficiency of photo-electric heating in the interfaces of ionized gas and molecular clouds is estimated at 0.1-0.3%. We confirm earlier indications of a low nitrogen content in the LMC. Evidence for solid state emission features is found in both young and evolved object; some of the YSOs are found to contain crystalline water ice.Comment: Accepted for publication in The Astronomical Journal. This paper accompanies the Summer 2009 SAGE-Spec release of 48 MIPS-SED spectra, but uses improved spectrum extraction. (Fig. 2 reduced resolution because of arXiv limit.

Improved Outcomes with Heavy Silicone Oil in Complex Primary Retinal Detachment: A Large Multicenter Matched Cohort Study

\ua9 2023 American Academy of OphthalmologyPurpose: To establish whether Densiron 68, a heavier-than-water endotamponade agent, is an effective alternative to conventional light silicone oil in primary rhegmatogenous retinal detachment (RD) surgery for eyes with inferior breaks in the detached retina and severe proliferative vitreoretinopathy (PVR). Design: Cohort study of routinely collected data from the European Society of Retina Specialists and British and Eire Association of Vitreoretinal Surgeons vitreoretinal database between 2015 and 2022. Participants: All consecutive eyes that underwent primary rhegmatogenous RD surgery using Densiron 68 or light silicone oil as an internal tamponade agent. Methods: To minimize confounding bias, we undertook 2:1 nearest-neighbor matching on inferior breaks, large inferior rhegmatogenous RDs, PVR, and, for visual analyses, baseline visual acuity (VA) between treatment groups. We fit regression models including prognostically relevant covariates, treatment–covariate interactions, and matching weights. We used g-computation with cluster-robust methods to estimate marginal effects. For nonlinear models, we calculated confidence intervals (CIs) using bias-corrected cluster bootstrapping with 9999 replications. Main Outcome Measures: Presence of a fully attached retina and VA at least 2 months after oil removal. Results: Of 1061 eyes enrolled, 426 and 239 were included in our matched samples for anatomic and visual outcome analyses, respectively. The primary success rate was higher in the Densiron 68 group (113 of 142; 80%) compared with the light silicone oil group (180 of 284; 63%), with an adjusted odds ratio of 1.90 (95% CI, 1.63–2.23, P < 0.001). We also observed a significant improvement favoring Densiron 68 of –0.26 logarithm of the minimum angle of resolution (logMAR) in postoperative VA between the 2 groups (95% CI, –0.43 to –0.10, P = 0.002). The anatomic benefit of using Densiron 68 in eyes with inferior retinal breaks and large detachments was more pronounced among eyes with PVR grade C. We found no evidence of visual effect moderation by anatomic outcome or foveal attachment. Conclusions: Densiron achieved higher anatomic success rates and improved visual outcomes compared with conventional light silicone oil in eyes with inferior retinal pathology and severe PVR. Financial Disclosure(s): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article

Search for the Higgs boson in events with missing transverse energy and b quark jets produced in proton-antiproton collisions at s**(1/2)=1.96 TeV

We search for the standard model Higgs boson produced in association with an electroweak vector boson in events with no identified charged leptons, large imbalance in transverse momentum, and two jets where at least one contains a secondary vertex consistent with the decay of b hadrons. We use ~1 fb-1 integrated luminosity of proton-antiproton collisions at s**(1/2)=1.96 TeV recorded by the CDF II experiment at the Tevatron. We find 268 (16) single (double) b-tagged candidate events, where 248 +/- 43 (14.4 +/- 2.7) are expected from standard model background processes. We place 95% confidence level upper limits on the Higgs boson production cross section for several Higgs boson masses ranging from 110 GeV/c2 to 140 GeV/c2. For a mass of 115 GeV/c2 the observed (expected) limit is 20.4 (14.2) times the standard model prediction.Comment: 8 pages, 2 figures, submitted to Phys. Rev. Let

Global Search for New Physics with 2.0/fb at CDF

Data collected in Run II of the Fermilab Tevatron are searched for indications of new electroweak-scale physics. Rather than focusing on particular new physics scenarios, CDF data are analyzed for discrepancies with the standard model prediction. A model-independent approach (Vista) considers gross features of the data, and is sensitive to new large cross-section physics. Further sensitivity to new physics is provided by two additional algorithms: a Bump Hunter searches invariant mass distributions for "bumps" that could indicate resonant production of new particles; and the Sleuth procedure scans for data excesses at large summed transverse momentum. This combined global search for new physics in 2.0/fb of ppbar collisions at sqrt(s)=1.96 TeV reveals no indication of physics beyond the standard model.Comment: 8 pages, 7 figures. Final version which appeared in Physical Review D Rapid Communication

Observation of Orbitally Excited B_s Mesons

We report the first observation of two narrow resonances consistent with states of orbitally excited (L=1) B_s mesons using 1 fb^{-1} of ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We use two-body decays into K^- and B^+ mesons reconstructed as B^+ \to J/\psi K^+, J/\psi \to \mu^+ \mu^- or B^+ \to \bar{D}^0 \pi^+, \bar{D}^0 \to K^+ \pi^-. We deduce the masses of the two states to be m(B_{s1}) = 5829.4 +- 0.7 MeV/c^2 and m(B_{s2}^*) = 5839.7 +- 0.7 MeV/c^2.Comment: Version accepted and published by Phys. Rev. Let

Utilisation of an operative difficulty grading scale for laparoscopic cholecystectomy

Background A reliable system for grading operative difficulty of laparoscopic cholecystectomy would standardise description of findings and reporting of outcomes. The aim of this study was to validate a difficulty grading system (Nassar scale), testing its applicability and consistency in two large prospective datasets. Methods Patient and disease-related variables and 30-day outcomes were identified in two prospective cholecystectomy databases: the multi-centre prospective cohort of 8820 patients from the recent CholeS Study and the single-surgeon series containing 4089 patients. Operative data and patient outcomes were correlated with Nassar operative difficultly scale, using Kendall’s tau for dichotomous variables, or Jonckheere–Terpstra tests for continuous variables. A ROC curve analysis was performed, to quantify the predictive accuracy of the scale for each outcome, with continuous outcomes dichotomised, prior to analysis. Results A higher operative difficulty grade was consistently associated with worse outcomes for the patients in both the reference and CholeS cohorts. The median length of stay increased from 0 to 4 days, and the 30-day complication rate from 7.6 to 24.4% as the difficulty grade increased from 1 to 4/5 (both p < 0.001). In the CholeS cohort, a higher difficulty grade was found to be most strongly associated with conversion to open and 30-day mortality (AUROC = 0.903, 0.822, respectively). On multivariable analysis, the Nassar operative difficultly scale was found to be a significant independent predictor of operative duration, conversion to open surgery, 30-day complications and 30-day reintervention (all p < 0.001). Conclusion We have shown that an operative difficulty scale can standardise the description of operative findings by multiple grades of surgeons to facilitate audit, training assessment and research. It provides a tool for reporting operative findings, disease severity and technical difficulty and can be utilised in future research to reliably compare outcomes according to case mix and intra-operative difficulty

Observation and Mass Measurement of the Baryon Ξb−\Xi^-_b

We report the observation and measurement of the mass of the bottom, strange baryon $\Xi^-_b$ through the decay chain $\Xi^-_b \to J/\psi \Xi^-$, where $J/\psi \to \mu^+ \mu^-$, $\Xi^- \to \Lambda \pi^-$, and $\Lambda \to p \pi^-$. Evidence for observation is based on a signal whose probability of arising from the estimated background is 6.6 x 10^{-15}, or 7.7 Gaussian standard deviations. The $\Xi^-_b$ mass is measured to be $5792.9\pm 2.5$ (stat.) $\pm 1.7$ (syst.) MeV/$c^2$.Comment: Minor text changes for the second version. Accepted by Phys. Rev. Let

Polarizations of J/psi and psi(2S) Mesons Produced in ppbar Collisions at 1.96 TeV

We have measured the polarizations of \jpsi and \psiprime mesons as functions of their transverse momentum \pt when they are produced promptly in the rapidity range $|y|<0.6$ with \pt \geq 5 \pgev. The analysis is performed using a data sample with an integrated luminosity of about 800 \ipb collected by the CDF II detector. For both vector mesons, we find that the polarizations become increasingly longitudinal as \pt increases from 5 to 30 \pgev. These results are compared to the predictions of nonrelativistic quantum chromodynamics and other contemporary models. The effective polarizations of \jpsi and \psiprime mesons from $B$-hadron decays are also reported.Comment: 8 pages, 7 figures, published in Physical Review Letter