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Context. Nearly a dozen star-forming galaxies have been detected in γ-rays by the Fermi observatory in the last decade. A remarkable property of this sample is the quasi-linear relation between the γ-ray luminosity and the star formation rate, which was obtained assuming that the latter is well traced by the infrared luminosity of the galaxies. The non-linearity of this relation has not been fully explained yet. Aims. We aim to determine the biases derived from the use of the infrared luminosity as a proxy for the star formation rate and to shed light on the more fundamental relation between the latter and the γ-ray luminosity. We expect to quantify and explain some trends observed in this relation. Methods. We compiled a near-homogeneous set of distances, ultraviolet, optical, infrared, and γ-ray fluxes from the literature for all known γ-ray emitting, star-forming galaxies. From these data, we computed the infrared and γ-ray luminosities, and star formation rates. We determined the best-fitting relation between the latter two, and we describe the trend using simple, population-orientated models for cosmic-ray transport and cooling. Results. We find that the γ-ray luminosity–star formation rate relation obtained from infrared luminosities is biased to shallower slopes. The actual relation is steeper than previous estimates, having a power-law index of 1.35 ± 0.05, in contrast to 1.23 ± 0.06. Conclusions. The unbiased γ-ray luminosity–star formation rate relation can be explained at high star formation rates by assuming that the cosmic-ray cooling region is kiloparsec-sized and pervaded by mild to fast winds. Combined with previous results about the scaling of wind velocity with star formation rate, our work provides support to advection as the dominant cosmic-ray escape mechanism in galaxies with low star formation rates.

Background and Purpose Diabetes is an independent risk factor for lacunar strokes. Few data are available regarding patient features, infarct location, and recurrent vascular events for diabetic patients with lacunar stroke. Methods We compared features at study entry and prognosis during 3.6 years of follow-up of diabetic vs. non-diabetic patients with recent lacunar stroke participating in the Secondary Prevention of Small Subcortical Strokes (SPS3) randomized trial. Results Among the 3020 participants, the prevalence of diabetes was 37% with a mean duration of 11 years. Diabetes was independently associated with slightly younger age (63 years vs. 64 years, p<0·001), Hispanic ethnicity (36% vs. 28%, p<0·0001), ischemic heart disease (11% vs. 6%, p=0·002), and peripheral vascular disease (5% vs. 2%, p<0·001). Diabetic patients more frequently had intracranial stenosis ≥50% (p<0·001), infarcts involving the brainstem or cerebellum (p<0·001), and more extensive white matter abnormalities (p<0·001). Diabetic patients were almost twice as likely to have a recurrent stroke (HR 1·8; 95% CI 1·4–2·3), recurrent ischemic stroke (HR 1·8; 95% CI 1·4–2·4), disabling/fatal stroke (HR 1·8; 95% CI 1·2–2·9), myocardial infarction (HR 1·7; 95% CI 1·0–2·8) and death (HR 2·1 (95% CI 1·6–2·8) compared with non-diabetics. Conclusions Diabetic patients with lacunar stroke have a distinctive clinical profile that includes double the prevalence of systemic and intracranial atherosclerosis, preferential involvement of the posterior circulation, and a poor prognosis for recurrent stroke and death.

Context. Recently, the colliding-wind region of the binary stellar system HD 93129A was resolved for the first time using Very Large Baseline Interferometry. This system, one of the most massive known binaries in our Galaxy, presents non-thermal emission in the radio band, which can be used to infer the physical conditions in the system, and make predictions for the high-energy band. Aims. We intend to constrain some of the unknown parameters of HD 93129A through modeling the non-thermal emitter. We also aim to analyse the detectability of this source in hard X-rays and γ-rays. Finally, we want to predict how the non-thermal emission will evolve in the future, when the stars approach periastron. Methods. A broadband radiative model for the wind-collision region (WCR) has been developed taking into account the evolution of the accelerated particles streaming along the shocked region, the emission by different radiative processes, and the attenuation of the emission propagating through the local matter and radiation fields. We reproduce the available radio data, and make predictions of the emission in hard X-rays and γ-rays under different assumptions.Results. From the analysis of the radio emission, we find that the binary HD 93129A is more likely to have a low inclination and a high eccentricity, with the more massive star being currently closer to the observer. The minimum energy of the non-thermal electrons seems to be between ∼20-100 MeV, depending on the intensity of the magnetic field in the WCR. The latter can be in the range ∼20-1500 mG. Conclusions. Our model is able to reproduce the observed radio emission, and predicts that the non-thermal radiation from HD 93129A will increase in the near future. With instruments such as NuSTAR, Fermi, and CTA, it will be possible to constrain the relativistic particle content of the source, and other parameters such as the magnetic field strength in the WCR which, in turn, can be used to obtain upper-limits of the magnetic field on the surface of the very massive stars, thereby inferring whether magnetic field amplification is taking place in the particle acceleration region.

Background— Strokes in patients with atrial fibrillation (AF) are typically larger, are associated with higher early mortality, and occur in older patients versus strokes in patients with sinus rhythm. Until recently, the value of antithrombotic therapies for acute stroke management has been based on empiric evidence. Summary of Review— We present a critical review of 3 randomized clinical trials testing aspirin, heparin/heparinoid, or both involving 5029 patients with AF and acute stroke. Early recurrent ischemic stroke occurred in about 5% of patients during the 2 to 4 weeks after initial stroke. Data conflict about whether early use of heparin/heparinoid reduced early recurrent ischemic stroke but are consistent regarding its lack of overall benefit on long-term functional outcome. Modest benefits for reduction of early recurrent stroke and functional outcome were associated with aspirin use, based largely on subgroup analysis from a single, large, unblinded trial. Conclusions— No benefit of heparin has been demonstrated for acute stroke patients with AF; whether selected subgroups would respond differently remains to be proven. Aspirin followed by early initiation of warfarin for long-term secondary prevention is reasonable antithrombotic management.

Context. Runaway stars produce bowshocks that are usually observed at infrared (IR) wavelengths. Non-thermal radio emission has been detected so far only from the bowshock of BD+43 • 3654, whereas the detection of non-thermal radiation from these bowshocks at high energies remains elusive. Aims. We aim at characterising in detail the radio, X-ray, and γ-ray emission from stellar bowshocks accounting for the structure of the region of interaction between the stellar wind and its environment. Methods. We develop a broadband-radiative, multi-zone model for stellar bowshocks that takes into account the spatial structure of the emitting region and the observational constraints. The model predicts the evolution and the emission of the relativistic particles accelerated and streaming together with the shocked flow. Results. We present broadband non-thermal spectral energy distributions for different scenarios, synthetic radio-cm synchrotron maps that reproduce the morphology of BD+43 • 3654, and updated predictions in X-ray and γ-ray energy ranges. We also compare the results of the multi-zone model applied in this work with those of a refined one-zone model. Conclusions.A multi-zone model provides better constraints than a one-zone model on the relevant parameters, namely the magnetic field intensity and the amount of energy deposited in non-thermal particles. However, one-zone models can be improved by carefully characterising the intensity of the IR dust photon field and the escape rate of the plasma from the shocked region. Finally, comparing observed radio maps with those obtained from a multi-zone model enables constraints to be obtained on the direction of stellar motion with respect to the observer.

Background and Purpose Inflammatory biomarkers predict incident and recurrent cardiac events, but their relationship to stroke prognosis is uncertain. We hypothesized that high-sensitivity C-reactive protein (hsCRP) predicts recurrent ischemic stroke after recent lacunar stroke. Methods Levels of Inflammatory Markers in the Treatment of Stroke (LIMITS) was an international, multicenter, prospective ancillary biomarker study nested within Secondary Prevention of Small Subcortical Strokes (SPS3), a Phase III trial in patients with recent lacunar stroke. Patients were assigned in factorial design to aspirin versus aspirin plus clopidogrel, and higher versus lower blood pressure targets. Patients had blood samples collected at enrollment, and hsCRP measured using nephelometry at a central laboratory. Cox proportional hazards models were used to calculate hazard ratios and 95% confidence intervals (HR, 95%CI) for recurrence risks before and after adjusting for demographics, comorbidities, and statin use. Results Among 1244 lacunar stroke patients (mean 63.3 ± 10.8 years), median hsCRP was 2.16 mg/L. There were 83 recurrent ischemic strokes (including 45 lacunes), and 115 major vascular events (stroke, myocardial infarction, vascular death). Compared with the bottom quartile, those in the top quartile (hsCRP >4.86 mg/L) were at increased risk of recurrent ischemic stroke (unadjusted HR 2.54, 95%CI 1.30–4.96), even after adjusting for demographics and risk factors (adjusted HR 2.32, 95%CI 1.15–4.68). HsCRP predicted increased risk of major vascular events (top quartile adjusted HR 2.04, 95%CI 1.14–3.67). There was no interaction with randomized antiplatelet treatment. Conclusions Among recent lacunar stroke patients, hsCRP levels predict risk of recurrent strokes and other vascular events. HsCRP did not predict response to dual antiplatelets.

Background and Purpose In the Secondary Prevention of Small Subcortical Strokes (SPS3) trial, addition of clopidogrel to aspirin was associated with an unexpected increase in mortality in patients with lacunar strokes. We assessed the effect of the addition of clopidogrel to aspirin on mortality in a meta-analysis of published randomized trials. Methods Randomized trials in which clopidogrel was added to aspirin in subjects with vascular disease or vascular risk factors were identified. Trials were restricted to those with a mean follow-up of ≥14 days in which both the combination of aspirin and clopidogrel was tested and mortality was reported. Results Twelve trials included 90 934 participants (mean age, 63 years; 70% men; median follow-up, 1 year) with 6849 observed deaths. There was no significant increase in mortality with the combination therapy either in 4 short-term (14 days–3 months; OR, 0.93; 95% CI, 0.87– 0.99) or in 7 long-term (>3 months; hazard ratio, 0.97; 95% CI, 0.91–1.04) trials after 1 long-term trial (the SPS3 trial) was excluded because of heterogeneity. Addition of clopidogrel was associated with an increase in fatal hemorrhage (OR, 1.35; 95% CI, 0.97–1.90) and a reduction in myocardial infarction (OR, 0.82; 95% CI, 0.74–0.91). Conclusions The addition of clopidogrel to aspirin has no overall effect on mortality. The SPS3 trial results are outliers, possibly because of a lower prevalence of coronary artery ischemia. Addition of clopidogrel to aspirin increases fatal bleeding and reduces myocardial infarction.