Porous single crystals are promising candidates for solar fuel production owing to their long range charge diffusion length, structural coherence, and sufficient reactive sites. Here, a simple ...template‐free method of growing a selectively branched, 2D anatase TiO2 porous single crystalline nanostructure (PSN) on fluorine‐doped tin oxide substrate is demonstrated. An innovative ion exchange–induced pore‐forming process is designed to successfully create high porosity in the single‐crystalline nanostructure with retention of excellent charge mobility and no detriment to crystal structure. PSN TiO2 film delivers a photocurrent of 1.02 mA cm−2 at a very low potential of 0.4 V versus reversible hydrogen electrode (RHE) for photo‐electrochemical water splitting, closing to the theoretical value of TiO2 (1.12 mA cm−2). Moreover, the current–potential curve featuring a small potential window from 0.1 to 0.4 V versus RHE under one‐sun illumination has a near‐ideal shape predicted by the Gartner Model, revealing that the charge separation and surface reaction on the PSN TiO2 photoanode are very efficient. The photo‐electrochemical water splitting performance of the films indicates that the ion exchange–assisted synthesis strategy is effective in creating large surface area and single‐crystalline porous photoelectrodes for efficient solar energy conversion.
A new strategy is developed to create high porosity and abundant reactive sites on TiO2 single‐crystalline nanostructures with retention of excellent charge mobility and no detriment to crystal structure. The novel porous single‐crystalline nanostructured film delivers excellent photo‐electrochemical performance, which sheds light on the design of high‐performing nanostructured materials.
Exchange‐rate policies are cornerstones of the world economy. They also have fundamental welfare and distributional consequences on nations, firms, and individuals. How do individuals internalize ...these consequences? We challenge the conventional wisdom on the source of mass preferences and argue that many individuals understand currency policies through the lens of inflation. Specifically, we argue that people who are concerned about inflation are more likely to support a fixed exchange rate regime and are more likely to oppose depreciation. We present observational and experimental evidence across middle‐income (Argentina and Serbia) and developed (United Kingdom) countries to support our argument. Further tests suggest that fears over purchasing power—instead of debt or savings considerations—drive inflation concerns.
Exchange rate volatility has undergone a secular decline since the collapse of the Bretton Woods system. We conjecture that this phenomenon may have led to a generalized decreased need for risk ...exchange hedging in financial markets. Indeed, we find that the negative association between bilateral foreign portfolio investments and the volatility of the exchange rate has markedly weakened over time. This finding, which is particularly significant for large countries and in the post-crisis period, can also help explain the decline in bilateral investments among EMU member countries. We observe, in fact, that, after 2012, the distinctive fall of Euro-area bilateral equity investments is significantly explained by the global declining effect of exchange rate volatility on financial markets. A lower exchange rate volatility, associated with the ensuing generalized reduction in the perceived exchange rate risk, may have posed a challenge to the economic relevance of the full exchange risk hedging system represented by the common currency area, and hence to the attractiveness of reciprocal investments.
Background Mutations in dedicator of cytokinesis 8 (DOCK8) cause a combined immunodeficiency (CID) also classified as autosomal recessive (AR) hyper-IgE syndrome (HIES). Recognizing patients with ...CID/HIES is of clinical importance because of the difference in prognosis and management. Objectives We sought to define the clinical features that distinguish DOCK8 deficiency from other forms of HIES and CIDs, study the mutational spectrum of DOCK8 deficiency, and report on the frequency of specific clinical findings. Methods Eighty-two patients from 60 families with CID and the phenotype of AR-HIES with (64 patients) and without (18 patients) DOCK8 mutations were studied. Support vector machines were used to compare clinical data from 35 patients with DOCK8 deficiency with those from 10 patients with AR-HIES without a DOCK8 mutation and 64 patients with signal transducer and activator of transcription 3 (STAT3) mutations. Results DOCK8-deficient patients had median IgE levels of 5201 IU, high eosinophil levels of usually at least 800/μL (92% of patients), and low IgM levels (62%). About 20% of patients were lymphopenic, mainly because of low CD4+ and CD8+ T-cell counts. Fewer than half of the patients tested produced normal specific antibody responses to recall antigens. Bacterial (84%), viral (78%), and fungal (70%) infections were frequently observed. Skin abscesses (60%) and allergies (73%) were common clinical problems. In contrast to STAT3 deficiency, there were few pneumatoceles, bone fractures, and teething problems. Mortality was high (34%). A combination of 5 clinical features was helpful in distinguishing patients with DOCK8 mutations from those with STAT3 mutations. Conclusions DOCK8 deficiency is likely in patients with severe viral infections, allergies, and/or low IgM levels who have a diagnosis of HIES plus hypereosinophilia and upper respiratory tract infections in the absence of parenchymal lung abnormalities, retained primary teeth, and minimal trauma fractures.
This paper provides new evidence on the role of exchange rates in forecasting commodity prices. Consistent with previous studies, we find that commodity currencies hold out-of-sample predictive power ...for commodity prices when using standard linear predictive regressions. After we reconsider the evidence using noncausal autoregressions, which provide a better fit to the data and are able to accommodate the effects of nonlinearities and omitted variables, the predictive power of exchange rates disappears.
•We use noncausal autoregressions to test the commodity currency hypothesis.•Exchange rates do not predict commodity prices.•Noncausal autoregressions fit commodity prices better than causal models.•Results are consistent with the financialization of commodity markets.
Since 2006, six satellites measuring solar‐induced chlorophyll fluorescence (SIF) have been launched to better constrain terrestrial gross primary productivity (GPP). The promise of the SIF signal as ...a proxy for photosynthesis with a strong relationship to GPP has been widely cited in carbon cycling studies. However, chlorophyll fluorescence originates from dynamic energy partitioning at the leaf level and does not exhibit a uniformly linear relationship with photosynthesis at finer scales. We induced stomatal closure in deciduous woody tree branches and measured SIF at a proximal scale, alongside leaf‐level gas exchange, pulse amplitude modulated (PAM) fluorescence, and leaf pigment content. We found no change in SIF or steady‐state PAM fluorescence, despite clear reductions in stomatal conductance, carbon assimilation, and light‐use efficiency in treated leaves. These findings suggest that equating SIF and photosynthesis is an oversimplification that may undermine the utility of SIF as a biophysical parameter in GPP models.
Plain Language Summary
Earth's vegetation plays a key role in storing carbon that would otherwise reside in the atmosphere. Recently, there has been increasing interest in measuring fluorescent light emitted by the chlorophyll in plant cells in order to track carbon uptake. Satellite fluorescence measurements show a strong, direct relationship with primary productivity. However, leaf‐level chlorophyll fluorescence studies have yielded insights into the origin of this signal as one of several pathways by which plants consume excess absorbed light. At finer scales, fluorescence emission may become inversely related to photosynthetic rate, due to the additional role of heat dissipation as an alternative pathway for plants to partition energy. To investigate the contradiction between measurements across scales, we experimentally manipulated tree branches, inhibiting photosynthesis by closing the stomata through which plants exchange water and carbon dioxide gases. We observed significant reductions in leaf‐level gas exchange in treated branches but found no similar change in fluorescence measured at the leaf level or from a proximal tower. While fluorescence offers physiological insights, we suggest that the close relationship with primary productivity at the satellite scale could result from a shared driver, such as chlorophyll content and that fluorescence data should be interpreted with care.
Key Points
Leaf‐level chlorophyll fluorescence does not exhibit a significant relationship with photosynthesis after inducing stomatal closure
Remote fluorescence data provide insight into the light reactions of photosynthesis, but do not directly track carbon assimilation
The link between fluorescence and primary productivity may result from shared drivers, such as chlorophyll content or energy partitioning
In recent years, Bitcoin exchange rate prediction has attracted the interest of researchers and investors. Some studies have used traditional statistical and econometric methods to understand the ...economic and technology determinants of Bitcoin, few have considered the development of predictive models using these determinants. In this study, we developed a two-stage approach for exploring whether the information hidden in economic and technology determinants can accurately predict the Bitcoin exchange rate. In the first stage, two nonlinear feature selection methods comprising an artificial neural network and random forest are used to reduce the subset of potential predictors by measuring the importance of economic and technology factors. In the second stage, the potential predictors are integrated into long short-term memory (LSTM) to predict the Bitcoin exchange rate regardless of the previous exchange rate. Our results showed that by using the economic and technology determinants, LSTM could achieve better predictive performance than the autoregressive integrated moving average, support vector regression, adaptive network fuzzy inference system, and LSTM methods, which all use the previous exchange rate. Thus, information obtained from economic and technology determinants is more important for predicting the Bitcoin exchange rate than the previous exchange rate.
Critical care medicine is a natural environment for machine learning approaches to improve outcomes for critically ill patients as admissions to ICUs generate vast amounts of data. However, ...technical, legal, ethical, and privacy concerns have so far limited the critical care medicine community from making these data readily available. The Society of Critical Care Medicine and the European Society of Intensive Care Medicine have identified ICU patient data sharing as one of the priorities under their Joint Data Science Collaboration. To encourage ICUs worldwide to share their patient data responsibly, we now describe the development and release of Amsterdam University Medical Centers Database (AmsterdamUMCdb), the first freely available critical care database in full compliance with privacy laws from both the United States and Europe, as an example of the feasibility of sharing complex critical care data.
University hospital ICU.
Data from ICU patients admitted between 2003 and 2016.
We used a risk-based deidentification strategy to maintain data utility while preserving privacy. In addition, we implemented contractual and governance processes, and a communication strategy. Patient organizations, supporting hospitals, and experts on ethics and privacy audited these processes and the database.
AmsterdamUMCdb contains approximately 1 billion clinical data points from 23,106 admissions of 20,109 patients. The privacy audit concluded that reidentification is not reasonably likely, and AmsterdamUMCdb can therefore be considered as anonymous information, both in the context of the U.S. Health Insurance Portability and Accountability Act and the European General Data Protection Regulation. The ethics audit concluded that responsible data sharing imposes minimal burden, whereas the potential benefit is tremendous.
Technical, legal, ethical, and privacy challenges related to responsible data sharing can be addressed using a multidisciplinary approach. A risk-based deidentification strategy, that complies with both U.S. and European privacy regulations, should be the preferred approach to releasing ICU patient data. This supports the shared Society of Critical Care Medicine and European Society of Intensive Care Medicine vision to improve critical care outcomes through scientific inquiry of vast and combined ICU datasets.
We analyse the reaction of the foreign exchange spot market to sovereign credit signals by Fitch, Moody’s and S&P during 1994–2010. We find that positive and negative credit news affects both the ...own-country exchange rate and other countries’ exchange rates. We provide evidence on unequal responses to the three agencies’ signals. Fitch signals induce the most timely market responses, and the market also reacts strongly to S&P negative outlook signals. Credit outlook and watch actions and multiple notch rating changes have more impact than one-notch rating changes. Considerable differences in the market reactions to sovereign credit events are highlighted in emerging versus developed economies, and in various geographical regions.
PDF
