Technology has facilitated new, nontraditional work arrangements, including the ride-sharing company Uber. Uber drivers provide rides anytime they choose. Using data on hourly earnings and driving, ...we document driver utilization of this real-time flexibility. We propose that the value of flexibility can be measured as deriving from time variation in the drivers’ reservation wage. Measuring time variation in drivers’ reservation wages allows us to estimate the surplus and labor supply implications of Uber relative to alternative, less-flexible work arrangements. Despite other drawbacks to the Uber arrangement, we estimate that Uber drivers earn more than twice the surplus they would in less-flexible arrangements.
In vertebrates, activation of innate immunity is an early response to injury, implicating it in the regenerative process. However, the mechanisms by which innate signals might regulate stem cell ...functionality are unknown. Here, we demonstrate that type 2 innate immunity is required for regeneration of skeletal muscle after injury. Muscle damage results in rapid recruitment of eosinophils, which secrete IL-4 to activate the regenerative actions of muscle resident fibro/adipocyte progenitors (FAPs). In FAPs, IL-4/IL-13 signaling serves as a key switch to control their fate and functions. Activation of IL-4/IL-13 signaling promotes proliferation of FAPs to support myogenesis while inhibiting their differentiation into adipocytes. Surprisingly, type 2 cytokine signaling is also required in FAPs, but not in myeloid cells, for rapid clearance of necrotic debris, a process that is necessary for timely and complete regeneration of tissues.
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► Type 2 cytokine signaling via IL-4Rα is required for muscle regeneration ► Eosinophils secrete IL-4 and are required for regeneration of injured muscle ► Myeloid or satellite cell IL-4Rα signaling is dispensable for muscle regeneration ► IL-4Rα signaling regulates the functions of fibro/adipogenic progenitors in muscle
Muscle injury promotes recruitment of eosinophils, immune cells that provide a niche for proliferating stem cells in regenerating muscle. Secretion of IL-4 by eosinophils promotes proliferation of fibro/adipogenic progenitors (FAPs) while inhibiting their differentiation into adipocytes, facilitating the engulfment of necrotic debris by FAPs.
Summary
Background
Magnetic resonance enterography (MRE) has been proposed as a non‐ionising alternative method to computed tomography enterography (CTE). Some studies have directly compared CTE and ...MRE in patients with small bowel Crohn's disease (CD) with variable results.
Aim
To compare the overall diagnostic accuracy in assessing the activity of small bowel and complications.
Methods
MEDLINE, EMBASE and Cochrane databases were searched for studies on the accuracy of MRE and CTE, as compared with a pre‐defined reference standard. Pooled sensitivity, specificity, the weighted area under the curve (AUC), incremental yield (IY) and other diagnostic indices were evaluated.
Results
A total of 290 CD patients from six different studies were analysed. The pooled sensitivity and specificity for MRE in detecting active small bowel CD was 87.9% 95% confidence interval (CI), 81.8–92.5 and 81.2% (95% CI: 71.9–88.4) respectively. The AUC under the summary receiver‐operating characteristic (sROC) of MRE was 0.905 (SEM 0.03, standard error of the mean). Likewise, the pooled sensitivity and specificity of CTE in detecting active small bowel CD was 85.8% (95% CI: 79.2–90.9) and 83.6% (95% CI: 75.3–90.1) with the AUC of 0.898. The AUC of MRE in detecting fistula, stenosis and abscess was 0.936, 0.931 and 0.996, respectively, compared to 0.963, 0.616 and 0.899 of CTE. No statistically significant IY for MRE vs. CTE was found (fixed model, P > 0.05).
Conclusions
Magnetic resonance enterography has a diagnostic effectiveness comparable to computed tomography enterography, thus may serve as a radiation‐free alternative for evaluation of patients with Crohn's disease.
Satellite observations show that leaf area index (LAI) has increased globally since 1981, but the impact of this vegetation structural change on the global terrestrial carbon cycle has not been ...systematically evaluated. Through process-based diagnostic ecosystem modeling, we find that the increase in LAI alone was responsible for 12.4% of the accumulated terrestrial carbon sink (95 ± 5 Pg C) from 1981 to 2016, whereas other drivers of CO
fertilization, nitrogen deposition, and climate change (temperature, radiation, and precipitation) contributed to 47.0%, 1.1%, and -28.6% of the sink, respectively. The legacy effects of past changes in these drivers prior to 1981 are responsible for the remaining 65.5% of the accumulated sink from 1981 to 2016. These results refine the attribution of the land sink to the various drivers and would help constrain prognostic models that often have large uncertainties in simulating changes in vegetation and their impacts on the global carbon cycle.
We describe a novel surgical technique in 31 women with histopathologically confirmed placenta accreta spectrum (PAS) disorders managed by a multidisciplinary team using a prophylactic infrarenal ...abdominal aortic cross‐clamping technique during caesarean hysterectomy. We conclude that this new surgical procedure is a relatively safe technique to potentially control operative blood loss. Our work may stimulate others to develop protocols assessing this innovative technique to improve the surgical outcome of PAS disorders.
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