Coherent master equation for laser modelocking

Modelocked lasers constitute the fundamental source of optically-coherent ultrashort-pulsed radiation, with huge impact in science and technology. Their modeling largely rests on the master equation (ME) approach introduced in 1975 by Hermann A. Haus. However, that description fails when the medium dynamics is fast and, ultimately, when light-matter quantum coherence is relevant. Here we set a rigorous and general ME framework, the coherent ME (CME), that overcomes both limitations. The CME predicts strong deviations from Haus ME, which we substantiate through an amplitude-modulated semiconductor laser experiment. Accounting for coherent effects, like the Risken-Nummedal-Graham-Haken multimode instability, we envisage the usefulness of the CME for describing self-modelocking and spontaneous frequency comb formation in quantum-cascade and quantum-dot lasers. Furthermore, the CME paves the way for exploiting the rich phenomenology of coherent effects in laser design, which has been hampered so far by the lack of a coherent ME formalism

Leukemic transformation of polycythemia vera: a single center study of 23 patients

BACKGROUND: Acute leukemia (AL) may occur as rare and late event of polycythemia vera (PV). METHODS: The current study included 23 patients who developed acute leukemia in a cohort of 414 consecutive PV patients with long-term observation (3208 person years of follow-up). Kaplan-Meier Product-Limit method was used to estimate the cumulative probability of survival; Gehan-Wilcoxon test was applied to compare survival in different groups of patients. RESULTS: Median age was 68 years, and 18 patients (78%) were > 60 years of age. At diagnosis of AL, most patients had a white blood count > 10 x 10(9)/L (n = 17; 74%), Hgb 50 x 10(9)/L (n = 17; 74%). Of 14 patients in whom cytogenetic analysis was available at leukemic transformation, 12 showed high-risk abnormalities including complex karyotype (n = 10), del (7)(q22) sole (n = 1) and del (X)(q26) sole (n = 1), whereas 2 had a normal karyotype. In patients whose karyotype was available at diagnosis of PV, cytogenetic evolution was documented at progression to AL. Treatment consisted of supportive care and/or low-dose chemotherapy (n = 15), or induction chemotherapy (n = 8). This included idarubicin plus cytarabine (n = 3), high-dose cytarabine (n = 4), and fludarabine-based regimen (n = 1). Allogenic stem cell transplantation was offered to a single patient, who is alive at Day + 70. The outcome of patients was poor, with a median survival of 2.9 months (range, 0.6-20.1 mos), with no significant differences between palliation and intensive treatments. CONCLUSIONS: AL following PV has distinct clinical and biologic features. Outcome of patients is poor irrespective of the treatment employed

Sex-, race-and ethnicity-based differences in thromboembolic events among adults hospitalized with COVID-19

BACKGROUND: Patients hospitalized with COVID-19 have an increased risk of thromboembolic events. Whether sex, race or ethnicity impacts these events is unknown. We studied the association between sex, race, and ethnicity and venous and arterial thromboembolic events among adults hospitalized with COVID-19. METHODS AND RESULTS: We used the American Heart Association Cardiovascular Disease COVID-19 registry. Primary expo-sures were sex and race and ethnicity, as defined by the registry. Primary outcomes were venous thromboembolic events and arterial thromboembolic events. We used logistic regression for risk adjustment. We studied 21 528 adults hospitalized with COVID-19 across 107 centers (54.1% men; 38.1% non-Hispanic White, 25.4% Hispanic, 25.7% non-Hispanic Black, 0.5% Native American, 4.0% Asian, 0.4% Pacific Islander, and 5.9% other race and ethnicity). The rate of venous thromboembolic events was 3.7% and was more common in men (4.2%) than women (3.2%; P\u3c0.001), and in non-Hispanic Black patients (4.9%) than other races and ethnicities (range, 1.3%– 3.8%; P\u3c0.001). The rate of arterial thromboembolic events was 3.9% and was more common in men (4.3%) than women (3.5%; P=0.002), and in non-Hispanic Black patients (5.0%) than other races and ethnicities (range, 2.3%– 4.7%; P\u3c0.001). Compared with men, women were less likely to experience venous thromboem-bolic events (adjusted odds ratio [OR], 0.71; 95% CI, 0.61– 0.83) and arterial thromboembolic events (adjusted OR, 0.76; 95% CI, 0.66– 0.89). Compared with non-Hispanic White patients, non-Hispanic Black patients had the highest likelihood of venous thromboembolic events (adjusted OR, 1.27; 95% CI, 1.04–1.54) and arterial thromboembolic events (adjusted OR, 1.35; 95% CI, 1.11–1.65). CONCLUSIONS: Men and non-Hispanic Black adults hospitalized with COVID-19 are more likely to have venous and arterial thromboembolic events. These subgroups may represent at-risk patients more susceptible to thromboembolic COVID-19 complications