עפרה תירוש-בקר, " 'חכמת אדם תאיר פניו', אשרינו שזכינו להיות מתלמידיו", לזכרו של יהושע בלאו, בעריכת סימון הופקינס, ירושלים: האקדמיה הלאומית הישראלית למדעים, תשפ"ג, עמ' 44-38.
Etan Cohen, Carmi, Tal , ו Lefstein, Adam . 2023. “The Marketization Of Education: A Microanalytic Analysis”. בתוך Proceedings Of The 17Th International Conference Of The Learning Sciences-Icls 2023, Pp. 1761-1762. International Society of the Learning Sciences.
Cyanobacteria inhabiting desert biological soil crusts face the harsh conditions of the desert. They evolved a suite of strategies toward desiccation-hydration cycles mixed with high light irradiations, etc. In this study we purified and characterized the structure and function of Photosystem I (PSI) from Leptolyngbya ohadii, a desiccation-tolerant desert cyanobacterium. We discovered that PSI forms tetrameric (PSI-Tet) aggregate. We investigated it by using sucrose density gradient centrifugation, clear native PAGE, high performance liquid chromatography, mass spectrometry (MS), time-resolved fluorescence (TRF) and time-resolved transient absorption (TA) spectroscopy. MS analysis identified the presence of two PsaB and two PsaL proteins in PSI-Tet and uniquely revealed that PsaLs are N-terminally acetylated in contrast to non-modified PsaL in the trimeric PSI from Synechocystis sp. PCC 6803. Chlorophyll (Chl) a fluorescence decay profiles of the PSI-Tet performed at 77 K revealed two emission bands at 690 nm and 725 nm with the former appearing only at early delay time. The main fluorescence emission peak, associated with emission from the low energy Chls a, decays within a few nanoseconds. TA studies demonstrated that the 725 nm emission band is associated with low energy Chls a with absorption band clearly resolved at 710 nm at 77 K. In summary, our work suggests that the heterogenous composition of PsaBs and PsaL in PSI-Tet is related with the adaptation mechanisms needed to cope with stressful conditions under which this bacterium naturally grows.
The publication in 1928 of W. Somerset Maugham’s collection of short stories Ashenden, or the British Agent set a new standard for espionage fiction. Based on the author’s own experience in intelligence work during World War I, three Ashenden stories discussed here, “Miss King,” “The Traitor,” and “Mr. Harrington’s Washing,” portray, in different ways, the pressures that history and ideological conflict place upon individuals and their relationships. Ashenden himself becomes subject to doubt, and often ends his mission in failure or at most an ambiguous victory. As one of the earliest protagonists of the modern espionage narrative, Maugham’s “British Agent” represents not only his nation at war but also the sense that that nation’s power and influence on the world stage are beginning to slip away.
September 2022: Martin Griffin is an associate professor in the Department of English at the University of Tennessee, Knoxville. His publications include Ashes of the Mind: War and Memory in Northern Literature, 1865-1900 (U. of Mass. Press 2009), Narrative, Identity, and the Map of Cultural Policy: Once Upon a Time in a Globalized World (with Constance DeVereaux, Ashgate, 2013), and an edited collection on the interactions of American literature and US political history, Stories of Nation: Fictions, Politics, and the American Experience (with Christopher Hebert, U. of Tenn. Press, 2017). He is currently completing a book-length study entitled Reading Espionage Fiction: Narrative, Conflict, and Commitment from WW1 to the Contemporary Era.
In quantitative content analysis, conventional wisdom holds that reliability, operationalized as agreement, is a necessary precondition for validity. Underlying this view is the assumption that there is a definite, unique way to correctly classify any instance of a measured variable. In this intervention, we argue that there are textual ambiguities that cause disagreement in classification that is not measurement error, but reflects true properties of the classified text. We introduce a notion of valid disagreement, a form of replicable disagreement that must be distinguished from replication failures that threaten reliability. We distinguish three key forms of meaning multiplicity that result in valid disagreement – ambiguity due to under-specification, polysemy due to excessive information, and interchangeability of classification choices – that are widespread in textual analysis, yet defy treatment within the confines of the existing content-analytic toolbox. Discussing implications, we present strategies for addressing valid disagreement in content analysis.
Resolving a complex policy problem often requires a mix of policy instruments and thus the identification of the most promising instrument combination. However, the relevant terminology of instrument interactions in a policy mix has not been standardized, hindering a straightforward identification of superior instrument combinations. To address this challenge, the chapter defines the terminology necessary for detecting three different possible policy instrument interactions—namely synergistic, counter-productive, and additive effects. It identifies two approaches to analyzing instrument mix effects: the “effect-based” and the “effort-based” methods. It then discusses the practical advantages and limitations of each approach and elaborates on key methodological issues that policy scholars and practitioners face at each step of developing a new policy mix.
From February to April 2020, as COVID-19 hit the U.S. economy, the official unemployment rate (UR) climbed from 3.5 percent—the lowest in more than 50 years—to 14.7—the highest since measurement began in January 1948. This unprecedented, speedy quadrupling of UR coincided with major disruptions in survey-data-collection procedures and a dramatic, differential drop in response rates.
To what extent did measurement issues contribute to this quadrupling? We revisit two recently studied potential biases in the Current Population Survey: rotation group bias (Krueger, Mas and Niu, 2017) and difficulty-of-reaching bias (Heffetz and Reeves, 2019). We extend the original analyses to the years prior to the crisis and focus on the six months of peak UR, from April to September 2020. Our ballpark estimates suggest that the peak official UR figure could be biased by up to ~1.5 percentage points in either direction.
Establishing accurate palaeo-hydroclimatic reconstructions from lacustrine and marine archives is a long-standing challenge in palaeoenvironment studies. Closed-basin evaporites, and especially halite, record episodes of extremely arid conditions during rapid climate change. However, the complex limnological behaviour of deep hypersaline water bodies and the stochastic nature of the hydroclimatic regime and its variations limit detailed palaeo-hydroclimatic interpretations from such records. Therefore, a mass-balance model was developed to explore hydrology–limnology–sedimentology relationships in hypersaline environments under both deterministic and stochastic approaches that generates synthetic halite–mud sequences. Applying the model to the Holocene Dead Sea halites yields novel insights into palaeoenvironmental conditions in the Levant. The deterministic framework indicates that: (i) under a series of similar hydroclimatic cycles, the thickness of each subsequent halite interval decreases, due to the depletion of dissolved-ions storage in the brine; (ii) halite deposition requires lake levels to drop below the minimal lake level of the preceding cycle; (iii) the time interval between halite deposition and the hydrological minimum is increasingly longer in subsequent cycles. Thus, counter-intuitively, halite deposition mostly takes place as water discharge increases, providing that the water balance is still negative. The stochastic approach produced random sequences comparable to the observed Dead Sea sedimentary record. It demonstrates that some hydrological minima are not represented by halite deposition at all. Furthermore, the thickness and number of halite beds at each hydrological cycle vary substantially, depending on the specific hydrological conditions realized. Finally, these results imply that the major Dead Sea level drop at the pre-Holocene deglaciation (ca 14 ka bp), previously assumed to be a record minimum, could not have been as pronounced as suggested, and must have been milder than the subsequent drop at the early Holocene (ca 11–10 ka bp).
