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We formalize the concept of "dark matter" in asset pricing models by quantifying the additional informativeness of cross‐equation restrictions about fundamental dynamics. The dark‐matter measure captures the degree of fragility for models that are potentially misspecified and unstable: a large dark‐matter measure indicates that the model lacks internal refutability (weak power of optimal specification tests) and external validity (high overfitting tendency and poor out‐of‐sample fit). The measure can be computed at low cost even for complex dynamic structural models. To illustrate its applications, we provide quantitative examples applying the measure to (time‐varying) rare‐disaster risk and long‐run risk models. [ABSTRACT FROM AUTHOR]

We show theoretically that variable production costs reduce systematic risk of firms' cash flows if capital and variable inputs are complementary in firms' production and input prices are procyclical. In our dynamic model, this operating hedge effect is weaker for more profitable firms, giving rise to a gross profitability premium. Moreover, gross profitability and value factors are distinct and negatively correlated, and their premia are not captured by the capital asset pricing model (CAPM). We estimate the model by simulated method of moments, and find that its main implications for stock returns and cash flow dynamics are quantitatively consistent with the data. [ABSTRACT FROM AUTHOR]

We propose a general simulation-based procedure for estimating the quality of approximate policies in heterogeneous-agent equilibrium models, which allows verification that such approximate solutions describe a near-rational equilibrium. Our procedure endows agents with superior knowledge of the future path of the economy, while imposing a suitable penalty for such foresight. The relaxed problem is more tractable than the original, and it results in an upper bound on agents' welfare. Our method is general and straightforward to implement, and it can be used in conjunction with various solution algorithms. We illustrate our approach in two applications: the incomplete-markets model of Krusell and Smith (1998) and the heterogeneous firm model of Khan and Thomas (2008). JEL classification: C86, D52 Key words: numerical solutions, accuracy, approximations, simulations https://dfi.frg/10.29338/wp2021-16, 1 Introduction Cross-sectional heterogeneity among households and firms is at the heart of many important economic phenomena. In general, it is impossible to aggregate a cross-section of agent characteristics in [...]

If these features are attested in non-standard Arabic dialects, but not in Classical Arabic, and cannot be attributed to a secondary development, then the conclusion must be that Classical Arabic is not more archaic than some non-standard Arabic dialects" (p. 442).[121] Among the archaic features of Neo-Arabic analyzed by Pat-El, the following are, in my view, worthy of a broader discussion. The Nabateo-Arabic Script and the Language of the Inscriptions Written in This Script" by Laïla Nehmé (pp. 75-98); "Arabic I alla i i / I illi i As Subordinators: An Alternative Perspective" by Lutz Edzard (pp. 212-26); "Orthography and Reading in Medieval Judaeo-Arabic" by Geoffrey Khan (pp. 395-404); "Linguistic History and the History of Arabic: A Speech Communities Approach" by A. Magidow (pp. 405-40); and "The Arabic Strata in Awjila Berber" by Marijn van Putten and Adam Benkato (pp. 476-502). By far the most striking example, telling much of the author's methodology and comparative Semitic erudition, is that of the Arabic word for "turtle" I sula fa i , which he confidently derives from I l f i "to wrap, to cover (oneself)" in Arabic and MSA (p. 196).[43] This derivation is totally meaningless in view of Akkadian I seleppû i (CAD S SB 2 sb 271) and Eblaite níg.u SB 9 sb .na = I sa-la-bù-um i (VE 47), pointing to a well-established Proto-Semitic animal name unrelated to any verbal root (SED II No. 202) - at least within the (pre-)history of Arabic and MSA.[44] Similarly infelicitous is Mascitelli's attempt to provide a South Arabian background for the pair I sql i - I ssql i (p. 195). Celebrating 400 Years of Arabic at Leiden University. [Extracted from the article]

The article aims at establishing new, more reliable meanings and functions for a number of lexical and semi-grammatical elements of Eblaite (Syrian East Semitic). The so-called "chancery texts", first published by Pelio Fronzaroli and Amalia Catagnoti as ARET 13, 16 and 18, are in the focus of the analysis. While feasible contextual interpretation is an absolute priority for the present authors, other (notably, comparative) methods are also used when applicable. As a result, a substantial progress in our understanding of these exceedingly difficult documents is expected to be achieved. [ABSTRACT FROM AUTHOR]

During the Syrian civil war, Syrian refugees crossed the Israeli border to receive medical treatment. During this time, Galilee Medical Center (GMC) became the main center for multidisciplinary treatment of these war-wounded patients. This retrospective study compares the demographics of local Israeli and refugee Syrian patients, as well as the volume and types of procedures each group received over a 5-year period. From January 2013 to December 2017, 963 unique patients underwent 1,751 procedures in the GMC Plastic Surgery Department. Of these patients, 176 were Syrian—including 42 children—and 787 were Israeli. These groups underwent 393 and 1,358 procedures, respectively, for a procedure-per-patient ratio of 2.23 versus 1.72, respectively. On average, Syrian patients tended to be younger than Israeli patients (23.6 vs. 49.25 years), had longer median hospitalization time (50 vs. 8 days), longer median operative times (102 vs. 85 minutes), and higher incidence of infection with multidrug-resistant bacteria (52.2 vs. 5.8%). Further, Syrian patients had more trauma-related procedures, such as skin grafts, wound debridement, and microsurgery, than Israeli patients. Through this process, GMC's plastic surgery department gained unprecedented exposure to a variety of complex procedures. [ABSTRACT FROM AUTHOR]

A model of a production economy in which real investment is irreversible and subject to convex adjustment costs is developed and presented. The tests based on empirical subjects support the findings of predictions for conditional volatility but not for expected returns.

Among the most important problems related to Russia's development, which are considered in depth in various kinds of forum and the media, both here and in the west, there is, [...]

This paper examines irreversible real investment through a general equilibrium model in a two-sector production economy. The model used provides more accurate information than partial equilibrium models.

This article invites the reader to revisit the ancient and universal genre of the lullaby. We start by pointing out that the lullaby has almost never been studied in its natural settings: instead, it is often approached exclusively as a heavily proofread literary text stripped from its context. Further, we focus on tendána, a lullaby from the island of Soqotra. The tendánas used for our analysis were collected from a largely preliterate, non-media-exposed culture and in natural settings. By running a comparison between tendánas and lullabies from a number of other cultures, we conclude that, although there are a number of similarities between them, tendánas also have several unique traits, among them a different sense of safety and danger, only sporadic use of onomatopoetic vocabulary, and an absence of cumulative and counting elements. [ABSTRACT FROM AUTHOR]

Chronic wounds are estimated to affect over 6 million people annually in the United States with an estimated annual cost of $25 billion. Debridement represents a key step in their management and is considered a basic necessity to induce the functional process of tissue repair. However, there is an unmet need for an efficient rapid acting non‐surgical debridement agent. Bromelain‐based enzymatic debridement has been proven to provide an effective, selective and safe non‐surgical debridement in deep burns. EscharEx (MediWound Ltd, Yavne, Israel), is a bromelain‐based enzymatic debridement agent currently in development for chronic wounds. The aim of this study was to assess its safety and efficacy in chronic wounds. Seventy‐three patients suffering from a lower extremity ulcer of diabetic/venous insufficiency/post‐surgical/traumatic aetiology were enrolled in a multicentre, assessor blinded, randomized controlled trial. Patients were randomized to topical treatment by either EscharEx or its gel vehicle for up to 10 daily 4 hour applications, and then continued follow‐up for up to 6 months. The EscharEx arm achieved a significantly higher incidence of complete debridement compared to the gel vehicle arm; 55 versus 29% (p =.047), thus meeting the primary endpoint of this study. The EscharEx and gel vehicle arms achieved similar reductions in wound area, non‐viable tissue area and wound healing scores during the debridement period. There were no significant differences between the arms in the incidence of complete wound closure (41% in the EsxcharEx arm vs. 53% in the gel vehicle arm) and in the mean time to complete wound closure (70.0 ± 32.8 days in the EsxcharEx arm vs. 65.7 ± 38.4 days in gel vehicle arm). There were no significant safety issues and EscharEx demonstrated a favourable benefit to risk profile. [ABSTRACT FROM AUTHOR]

We test the hypothesis that if poor accounting quality (AQ) is associated with poor investor understanding of firms' revenue and cost structures, then poor AQ stocks likely respond more slowly than good AQ stocks to new non‐idiosyncratic information that affects both sets of firms. Consistent with this, results indicate that stock returns of good AQ firms significantly positively predict one‐month‐ahead stock returns to industry‐ and size‐matched poor AQ firms. In testing a delayed‐information‐processing mechanism behind the cross‐firm return predictability, we find that: (i) analyst earnings forecast revisions (FR) mimic the return patterns, as FR of good AQ firms significantly positively predict one‐month‐ahead FR of matched poor AQ firms; (ii) cross‐firm return predictability is concentrated in months with substantial news arrival, including months with Federal Open Market Committee (FOMC) rate announcements, but not in no‐news months; (iii) cross‐firm return predictability is stronger when the good AQ predictor firms have a richer information environment than poor AQ firms as proxied by analyst following, institutional ownership, and the presence of a Big 4 auditor. Collectively, the results uncover a new relation between accounting quality and stock return dynamics. [ABSTRACT FROM AUTHOR]

Temporal granularity is developed as a concept and used in a model to examine the behavior of derivatives.

We develop a general equilibrium model of asset prices in which benefits of technological innovation are distributed asymmetrically. Financial market participants do not capture all economic gains from innovation even when they own shares in innovating firms. Such gains accrue partly to the innovators, who cannot sell claims on proceeds from their future ideas. We show how the resulting inequality among agents can give rise to a high risk premium on the aggregate stock market, return comovement and average return differences among firms, and the failure of traditional representative agent asset pricing models to account for cross-sectional differences in risk premia. [ABSTRACT FROM AUTHOR]