Attention to attributes and objects in working memory

It has been debated on the basis of change-detection procedures whether visual working memory is limited by the number of objects, task-relevant attributes within those objects, or bindings between attributes. This debate, however, has been hampered by several limitations, including the use of conditions that vary between studies and the absence of appropriate mathematical models to estimate the number of items in working memory in different stimulus conditions. We re-examined working memory limits in two experiments with a wide array of conditions involving color and shape attributes, relying on a set of new models to fit various stimulus situations. In Experiment 2, a new procedure allowed identical retrieval conditions across different conditions of attention at encoding. The results show that multiple attributes compete for attention, but that retaining the binding between attributes is accomplished only by retaining the attributes themselves. We propose a theoretical account in which a fixed object capacity limit contains within it the possibility of the incomplete retention of object attributes, depending on the direction of attention

Improved Co I Log(gf) Values and Abundance Determinations in the Photospheres of the Sun and Metal-Poor Star HD 84937

New emission branching fraction measurements for 898 lines of the first spectrum of cobalt (Co I) are determined from hollow cathode lamp spectra recorded with the National Solar Observatory 1 m Fourier transform spectrometer on Kitt Peak, AZ and a high-resolution echelle spectrometer. Published radiative lifetimes from laser induced fluorescence measurements are combined with the branching fractions to determine accurate absolute atomic transition probabilities for the 898 lines. Hyperfine structure (hfs) constants for levels of neutral Co in the literature are surveyed and selected values are used to generate complete hfs component patterns for 195 transitions of Co I. These new laboratory data are applied to determine the Co abundance in the Sun and metal-poor star HD 84937, yielding log epsilon(Co) = 4.955 +/- 0.007 (sigma = 0.059) based on 82 Co I lines and log epsilon(Co) = 2.785 +/- 0.008 (sigma = 0.065) based on 66 Co I lines, respectively. A Saha or ionization balance test on the photosphere of HD 84937 is performed using 16 UV lines of Co II, and good agreement is found with the Co I result in this metal-poor ([Fe I/H] = -2.32, [Fe II/H] = -2.32) dwarf star. The resulting value of [Co/Fe]= +0.14 supports a rise of Co/Fe at low metallicity that has been suggested in other studies.NASA NNX10AN93GNSF AST-1211055, AST-1211585McDonald Observator

Drafting in Self-Timed Circuits

Intervals between data items propagating in self-timed circuits are controlled by handshake signals rather than by a clock. The sequence of handshakes can be abstracted as the movement of “tokens”. In many self-timed designs, a trailing token will catch up with a leading token, even when it trails by thousands of gate delays. Simulations in SPICE of a simple GasP circular FIFO reveal this effect. Contrary to earlier work, we find the cause of drafting to be charge stored on an isolated node between two series transistors. This mechanism occurs in many decision gates that implement a logical AND. The charge on the floating internal node can drift between actions and thereby change the delay of the gate. Drafting occurs because the delay of a trailing token through a self-timed stage depends on when the leading token departed. This effect, called “drafting”, can be seen in many of the self-timed designs, e.g., GasP, Mousetrap, Click, Micropipeline. Drafting behavior may be modulated by controlling the internal node of the GasP NOR gate. This offers possibilities for using self-timed circuits in applications where the interval between data items carries information for spiking neural networks, security or real-time signal processing

Drug Trafficking, State Capacity, and the Post-Soviet Condition in the Kyrgyz Republic

Following the collapse of the Soviet Union, the newly independent states of Central Asia faced numerous challenges. These included cultivating new national identities and state capacity, managing new borders, and addressing issues of conflict and political violence. Converging with these challenges – a booming trade in opium and heroin originating in neighboring Afghanistan. Central Asia quickly became a key route for opiates originating in Afghanistan and transiting to Russia and Europe. The Kyrgyz Republic lies at the southeastern corner of this region, along one of the world’s busiest drug trafficking routes. This thesis examines state and societal responses to narcotics trafficking in the Kyrgyz Republic with a specific emphasis on the role of ethnicity, religion, kinship, and patronage networks. In doing so, it seeks to discern the role played by narcotics trafficking in the broader political-geographic space of the Republic, paying specific attention to state capacity. Likewise, it is interested in how these processes both shape and are shaped by political-geographic space. It relies on publicly available data provided by the Kyrgyz Government as well as the UNODC. More importantly, it derives context from a series of interviews and observations obtained during fieldwork in the Kyrgyz Republic during the summer of 2018. These interviews – conducted with officials from academia, non-governmental organizations, international governmental organizations, diplomatic missions, and the Kyrgyz government, provide critical context to broader research efforts and previous work conducted on this subject. This thesis ultimately supports some recent scholarship conducted on narcotics trafficking in the Republic, while also challenging the premises of older discourse on the drug trade in the region. In doing so it hopes to reinvigorate scholarship and policy debates on the Eurasian narcotics trade and broader illicit geographies

Financial Diversification, Sudden Stops and Sudden Starts

The recent literature on sudden stops is based on the fact that many emerging market economies experience recurrent and sharp capital account reversals. In this paper we argue, as some recent research has started to emphasize, that more information can be obtained by looking at gross rather than net flows. Economies may be curtailed from international financial markets, resulting in a sudden stop of inflows, but others may be experiencing portfolio shifts that cause sudden start of capital outflows. By looking at gross flows, and comparing emerging markets (EMEs) with developed economies (DEs) we indeed show that there is a variety of experiences that cannot be lumped together. In particular, sudden stop of inflows are as common in DEs as in EMEs, but a key difference is that in the former outflows and inflows are negatively correlated, which dampen the reversal of net flows. We present a model of financial diversification to interpret these results which is consistent with most evidence we report here. l II) could be helpful on this task.

Models of verbal working memory capacity: What does it take to make them work?

Theories of working memory (WM) capacity limits will be more useful when we know what aspects of performance are governed by the limits and what aspects are governed by other memory mechanisms. Whereas considerable progress has been made on models of WM capacity limits for visual arrays of separate objects, less progress has been made in understanding verbal materials, especially when words are mentally combined to form multiword units or chunks. Toward a more comprehensive theory of capacity limits, we examined models of forced-choice recognition of words within printed lists, using materials designed to produce multiword chunks in memory (e.g., leather brief case). Several simple models were tested against data from a variety of list lengths and potential chunk sizes, with test conditions that only imperfectly elicited the interword associations. According to the most successful model, participants retained about 3 chunks on average in a capacity-limited region of WM, with some chunks being only subsets of the presented associative information (e.g., leather brief case retained with leather as one chunk and brief case as another). The addition to the model of an activated long-term memory component unlimited in capacity was needed. A fixed-capacity limit appears critical to account for immediate verbal recognition and other forms of WM. We advance a model-based approach that allows capacity to be assessed despite other important processing contributions. Starting with a psychological-process model of WM capacity developed to understand visual arrays, we arrive at a more unified and complete model

Improved Log(gf) Values for Lines of Ti I and Abundance Determinations in the Photospheres of the Sun and Metal-Poor Star HD 84937 (Accurate Transition Probabilities for Ti I)

New atomic transition probability measurements for 948 lines of Ti I are reported. Branching fractions from Fourier transform spectra and from spectra recorded using a 3 m echelle spectrometer are combined with published radiative lifetimes from laser-induced fluorescence measurements to determine these transition probabilities. Generally good agreement is found in comparisons to the NIST Atomic Spectra Database. The new Ti I data are applied to re-determine the Ti abundance in the photospheres of the Sun and metal-poor star HD 84937 using many lines covering a range of wavelength and excitation potential to explore possible non-local thermal equilibrium effects. The variation of relative Ti/Fe abundance with metallicity in metal-poor stars observed in earlier studies is supported in this study.NSF AST-1211055, AST-0908978, AST-1211585NSF REU grant AST-1004881ESO Science Archive Facility 073.D-0024, 266.D-5655NASA NAS 5-26555Astronom