592 research outputs found

    Efficient Bimolecular Mechanism of Photochemical Hydrogen Production Using Halogenated Boron-Dipyrromethene (Bodipy) Dyes and a Bis(dimethylglyoxime) Cobalt(III) Complex

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    A series of Boron-­dipyrromethene (Bodipy) dyes were used as photosensitizers for photochemical hydrogen production in conjunction with [CoIII(dmgH)2pyCl] (where dmgH = dimethylglyoximate, py = pyridine) as the catalyst and triethanolamine (TEOA) as the sacrificial electron donor. The Bodipy dyes are fully characterized by electrochemistry, x-­‐ray crystallography, quantum chemistry calculations, femtosecond transient absorption and time-­‐resolved fluorescence, as well as in long-­‐term hydrogen production assays. Consistent with other recent reports, only systems containing halogenated chromophores were active for hydrogen production, as the long-­‐lived triplet state is necessary for efficient bimolecular electron transfer. Here, it is shown that the photostability of the system improves with Bodipy dyes containing a mesityl group versus a phenyl group, which is attributed to increased electron donating character of the mesityl substituent. Unlike previous reports, the optimal ratio of chromophore to catalyst is established and shown to be 20:1, at which point this bimolecular dye/catalyst system performs 3-­‐4 times better than similar chemically linked systems. We also show that the hydrogen production drops dramatically with excess catalyst concentration. The maximum turnover number of ~700 (with respect to chromophore) is obtained under the following conditions: 1.0 × 10­‐4 M [Co(dmgH)2pyCl], 5.0 × 10-6 M Bodipy dye with iodine and mesityl substituents, 1:1 v:v (10% aqueous TEOA):MeCN (adjusted to pH 7), and irradiation by light with λ \u3e 410 nm for 30 h. This system, containing discrete chromophore and catalyst, is more active than similar linked Bodipy – Co(dmg)2 dyads recently published, which, in conjunction with our other measurements, suggests that the nominal dyads actually function bimolecularly

    Association between the COVID-19 pandemic and insurance-based disparities in mortality after major surgery among US adults

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    Importance: The COVID-19 pandemic caused significant disruptions in surgical care. Whether these disruptions disproportionately impacted economically disadvantaged individuals is unknown. Objective: To evaluate the association between the COVID-19 pandemic and mortality after major surgery among patients with Medicaid insurance or without insurance compared with patients with commercial insurance. Design, Setting, and Participants: This cross-sectional study used data from the Vizient Clinical Database for patients who underwent major surgery at hospitals in the US between January 1, 2018, and May 31, 2020. Exposures: The hospital proportion of patients with COVID-19 during the first wave of COVID-19 cases between March 1 and May 31, 2020, stratified as low (≤5.0%), medium (5.1%-10.0%), high (10.1%-25.0%), and very high (\u3e25.0%). Main Outcomes and Measures: The main outcome was inpatient mortality. The association between mortality after surgery and payer status as a function of the proportion of hospitalized patients with COVID-19 was evaluated with a quasi-experimental triple-difference approach using logistic regression. Results: Among 2 950 147 adults undergoing inpatient surgery (1 550 752 female [52.6%]) at 677 hospitals, the primary payer was Medicare (1 427 791 [48.4%]), followed by commercial insurance (1 000 068 [33.9%]), Medicaid (321 600 [10.9%]), other payer (140 959 [4.8%]), and no insurance (59 729 [2.0%]). Mortality rates increased more for patients undergoing surgery during the first wave of the pandemic in hospitals with a high COVID-19 burden (adjusted odds ratio [AOR], 1.13; 95% CI, 1.03-1.24; P = .01) and a very high COVID-19 burden (AOR, 1.38; 95% CI, 1.24-1.53; P \u3c .001) compared with patients in hospitals with a low COVID-19 burden. Overall, patients with Medicaid had 29% higher odds of death (AOR, 1.29; 95% CI, 1.22-1.36; P \u3c .001) and patients without insurance had 75% higher odds of death (AOR, 1.75; 95% CI, 1.55-1.98; P \u3c .001) compared with patients with commercial insurance. However, mortality rates for surgical patients with Medicaid insurance (AOR, 1.03; 95% CI, 0.82-1.30; P = .79) or without insurance (AOR, 0.85; 95% CI, 0.47-1.54; P = .60) did not increase more than for patients with commercial insurance in hospitals with a high COVID-19 burden compared with hospitals with a low COVID-19 burden. These findings were similar in hospitals with very high COVID-19 burdens. Conclusions and Relevance: In this cross-sectional study, the first wave of the COVID-19 pandemic was associated with a higher risk of mortality after surgery in hospitals with more than 25.0% of patients with COVID-19. However, the pandemic was not associated with greater increases in mortality among patients with no insurance or patients with Medicaid compared with patients with commercial insurance in hospitals with a very high COVID-19 burden

    Elephants classify human ethnic groups by odor and garment color

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    Animals can benefit from classifying predators or other dangers into categories, tailoring their escape strategies to the type and nature of the risk. Studies of alarm vocalizations have revealed various levels of sophistication in classification [1-5]. In many taxa, reactions to danger are inflexible, but some species can learn the level of threat presented by the local population of a predator [6-8] or by specific, recognizable individuals [9-10]. Some species distinguish several species of predator, giving differentiated warning calls and escape reactions; here we explore an animal’s classification of sub-groups within a species. We show that elephants distinguish at least two Kenyan ethnic groups, and can identify them by olfactory and color cues independently. In the Amboseli ecosystem, Kenya, Maasai warriors demonstrate virility by spearing elephants (Loxodonta africana), but Kamba agriculturalists pose little threat. Elephants showed greater fear when they detected the scent of garments previously worn by Maasai than by Kamba men, and reacted aggressively to the color associated with Maasai warriors. Elephants are therefore able to classify members of a single species into sub-groups that pose different degrees of danger

    Democracy in trade unions, democracy through trade unions?

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    Since the Webbs published Industrial Democracy at the end of the nineteenth century, the principle that workers have a legitimate voice in decision-making in the world of work – in some versions through trade unions, in others at least formally through separate representative structures – has become widely accepted in most west European countries. There is now a vast literature on the strengths and weaknesses of such mechanisms, and we review briefly some of the key interpretations of the rise (and fall) of policies and structures for workplace and board-level representation. We also discuss the mainly failed attempts to establish broader processes of economic democracy, which the eclipse of nationally specific mechanisms of class compromise makes again a salient demand. Economic globalization also highlights the need for transnational mechanisms to achieve worker voice (or more radically, control) in the dynamics of capital-labour relations. We therefore examine the role of trade unions in coordinating pressure for a countervailing force at European and global levels, and in the construction of (emergent?) supranational industrial relations. However, many would argue that unions cannot win legitimacy as democratizing force unless manifestly democratic internally. We therefore revisit debates on and dilemmas of democracy within trade unions, and examine recent initiatives to enhance democratization

    Mobile Enhancement of Motivation in Schizophrenia: A Pilot Randomized Controlled Trial of a Personalized Text Message Intervention for Motivation Deficits

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    Objective: Motivation deficits remain an unmet treatment need in schizophrenia. Recent research has identified mechanisms underlying motivation deficits (i.e., impaired effort-cost computations, reduced future reward-value representation maintenance) that may be effective treatment targets to improve motivation. This study tested the feasibility and preliminary effectiveness of Mobile Enhancement of Motivation in Schizophrenia (MEMS), an intervention that leverages mobile technology to target these mechanisms with text messages. Method: Fifty-six participants with a schizophrenia-spectrum disorder were randomized to MEMS (n = 27) or a control condition (n = 29). All participants set recovery goals to complete over 8 weeks. Participants in the MEMS group additionally received personalized, interactive text messages on their personal cellphones each weekday. Results: Retention and engagement in MEMS were high: 92.6% completed 8 weeks of MEMS, with an 86.1% text message response rate, and 100% reported being satisfied with the text messages. Compared to participants in the control condition, the participants in the MEMS condition had significantly greater improvements in interviewer-rated motivation and anticipatory pleasure and attained significantly more recovery-oriented goals at 8 weeks. There were no significant group differences in purported mechanisms (performance-based effort-cost computations and future reward-value representations) or in self-reported motivation, quality of life, or functioning. Conclusion: Results demonstrate that MEMS is feasible as a brief, low-intensity mobile intervention that could effectively improve some aspects of motivation (i.e., initiation and maintenance of goal-directed behaviors) and recovery goal attainment for those with schizophrenia-spectrum disorders. More work is needed with larger samples and to understand the mechanisms of change in MEMS

    First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data

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    Spinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signalto- noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have been developed, allowing a fully coherent search for gravitational waves from known pulsars over a fraction of a hertz and several spin-down values. In this paper we describe a narrow-band search of 11 pulsars using data from Advanced LIGO’s first observing run. Although we have found several initial outliers, further studies show no significant evidence for the presence of a gravitational wave signal. Finally, we have placed upper limits on the signal strain amplitude lower than the spin-down limit for 5 of the 11 targets over the bands searched; in the case of J1813-1749 the spin-down limit has been beaten for the first time. For an additional 3 targets, the median upper limit across the search bands is below the spin-down limit. This is the most sensitive narrow-band search for continuous gravitational waves carried out so far

    Pass a Law, Any Law, Fast! State Legislative Responses to the Kelo Backlash

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    The Supreme Court in Kelo v. City of New London left protection of property against takings for economic development to the states. Since Kelo, thirty-seven states have enacted legislation to update their eminent domain laws. This paper is the first to theoretically and empirically analyze the factors that influence whether, in what manner, and how quickly states change their laws through new legislation. Fourteen of the thirty-seven new laws offer only weak protections against development takings. The legislative response to Kelo was responsive to measures of the backlash but only in the binary decision whether to pass any new law. The decision to enact a meaningful restriction was more a function of relevant political economy measures. States with more economic freedom, greater value of new housing construction, and less racial and income inequality are more likely to have enacted stronger restrictions, and sooner. Of the thirteen states that have not updated, Arkansas, Oklahoma and Mississippi are highly likely to do so in the future. Hawaii, Massachusetts and New York are unlikely to update ever if at all
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