Predictive context biases perceptual selection during binocular rivalry

Prediction may be a fundamental principle of sensory processing, such that the brain continuously generates predictions about forthcoming sensory information. However, little is known about how prediction contributes to the selection of a conscious percept from among competing alternatives. Here, we used binocular rivalry to investigate the effects of prediction on perceptual selection. In binocular rivalry, incompatible images presented to the two eyes result in a perceptual alternation between the images, even though the visual stimuli remain constant. If predictive signals influence the competition between neural representations of rivalrous images, this influence should generate a bias in perceptual selection that depends on predictive context. To manipulate predictive context, we developed a novel binocular rivalry paradigm in which orthogonal rivalrous test gratings were immediately preceded by rotating gratings presented identically to the two eyes. One of the rivalrous gratings had an orientation that was consistent with the preceding rotation direction (it was the expected next image in the series), and the other had an inconsistent orientation. We found that human observers were more likely to perceive the consistent grating, suggesting that predictive context biased selection in favor of the predicted percept. This prediction effect depended on only recent stimulus history, and it could be dissociated from another stimulus history effect related to orientation-specific adaptation. Since binocular rivalry between orthogonal gratings is thought to be resolved at an early stage of visual processing, these results suggest that predictive signals may exist at low levels of the visual processing hierarchy and that these signals can bias conscious perception. In the future, this paradigm could be used to test whether visual percepts are generated from the combination of prior information and incoming sensory information according to Bayesian principles

Davis v. Department of Revenue of Kentucky: A Preliminary Impact Assessment

States with income taxes frequently exempt municipal bond interest from state taxation. Such exemptions, referred to as double exempts, are tax expenditures that reduce state revenues, but are viewed as a subsidy to the cost of capital for the state and its localities. All but a few states provide the income tax exemption for state based issues while taxing interest from municipal bonds issued by muni issuers in other states. A recent court case, Davis vs. Department of Revenue of Kentucky, declared state statutes limiting the state income tax exemptions to ”in-state” issues unconstitutional. This paper provides some legal background and context for the current case and addresses two key fiscal implications of this case. First, the paper presents a basic model that suggests that bonds issued by states with higher marginal tax rates would see the yields increase on their obligations while states with lower than average marginal tax rates would see their yields decline. The yields would converge at new market equilibrium due to the elimination of tax preferences across the states. Second, the preliminary estimates suggest a good deal of variance in how much tax revenue each state will lose if the case is upheld by the Supreme Court.

Is the EU-Central Asia Strategy running out of steam? EUCAM Policy Brief No. 17, May 2011

The EU’s Central Asia Strategy approaches its fourth anniversary. In that time the EU has placed its relationship with Central Asia on a more structured footing. Although progress has been made in building dialogue and in furthering engagement, the strategy’s limitations are increasingly obvious. This brief argues that the driving force of the EU engagement should be based on a closer link between security and development. Engagement in this broad field should be underpinned by a values based approach that seeks to promote more explicitly reform on human rights, rule of law, governance and democracy. The momentous changes sweeping across the Middle East and North Africa have demonstrated that even the most apparently durable authoritarian regimes are vulnerable to sudden political shocks

Effect of Benzene and Ethylbenzene on the Transcription of methyl-\u3cem\u3etert\u3c/em\u3e-butyl Ether Degradation Genes of \u3cem\u3eMethylibium petroleiphilum\u3c/em\u3e PM1

Methyl-tert-butyl ether (MTBE) and its degradation by-product, tert-butyl alcohol (TBA), are widespread contaminants detected frequently in groundwater in California. Since MTBE was used as a fuel oxygenate for almost two decades, leaking underground fuel storage tanks are an important source of contamination. Gasoline components such as BTEX (benzene, toluene, ethylbenzene and xylenes) are often present in mixtures with MTBE and TBA. Investigations of interactions between BTEX and MTBE degradation have not yielded consistent trends, and the molecular mechanisms of BTEX compounds’ impact on MTBE degradation are not well understood. We investigated trends in transcription of biodegradation genes in the MTBE-degrading bacterium, Methylibium petroleiphilum PM1 upon exposure to MTBE, TBA, ethylbenzene and benzene as individual compounds or in mixtures. We designed real-time quantitative PCR assays to target functional genes of strain PM1 and provide evidence for induction of genes mdpA (MTBE monooxygenase), mdpJ (TBA hydroxylase) and bmoA (benzene monooxygenase) in response to MTBE, TBA and benzene, respectively. Delayed induction of mdpA and mdpJ transcription occurred with mixtures of benzene and MTBE or TBA, respectively. bmoA transcription was similar in the presence of MTBE or TBA with benzene as in their absence. Our results also indicate that ethylbenzene, previously proposed as an inhibitor of MTBE degradation in some bacteria, inhibits transcription of mdpA, mdpJ and bmoAgenes in strain PM1

Gene \u3cem\u3emdpC\u3c/em\u3e Plays a Regulatory Role in the Methyl-\u3cem\u3etert\u3c/em\u3e-butyl Ether Degradation Pathway of \u3cem\u3eMethylibium petroleiphilum\u3c/em\u3e Strain PM1

Among the few bacteria known to utilize methyl tert-butyl ether (MTBE) as a sole carbon source, Methylibium petroleiphilum PM1 is a well-characterized organism with a sequenced genome; however, knowledge of the genetic regulation of its MTBE degradation pathway is limited. We investigated the role of a putative transcriptional activator gene, mdpC, in the induction of MTBE-degradation genes mdpA (encoding MTBE monooxygenase) and mdpJ (encoding tert-butyl alcohol hydroxylase) of strain PM1 in a gene-knockout mutant mdpC−. We also utilized quantitative reverse transcriptase PCR assays targeting genes mdpA, mdpJ and mdpC to determine the effects of the mutation on transcription of these genes. Our results indicate that gene mdpC is involved in the induction of both mdpA and mdpJ in response to MTBE and tert-butyl alcohol (TBA) exposure in PM1. An additional independent mechanism may be involved in the induction of mdpJ in the presence of TBA

Chemicals having estrogenic activity can be released from some bisphenol a-free, hard and clear, thermoplastic resins

Background: Chemicals that have estrogenic activity (EA) can potentially cause adverse health effects in mammals including humans, sometimes at low doses in fetal through juvenile stages with effects detected in adults. Polycarbonate (PC) thermoplastic resins made from bisphenol A (BPA), a chemical that has EA, are now often avoided in products used by babies. Other BPA-free thermoplastic resins, some hypothesized or advertised to be EA-free, are replacing PC resins used to make reusable hard and clear thermoplastic products such as baby bottles. Methods: We used two very sensitive and accurate in vitro assays (MCF-7 and BG1Luc human cell lines) to quantify the EA of chemicals leached into ethanol or water/saline extracts of fourteen unstressed or stressed (autoclaving, microwaving, UV radiation) thermoplastic resins. Estrogen receptor (ER)-dependent agonist responses were confirmed by their inhibition with the ER antagonist ICI 182,780. Results: Our data showed that some (4/14) unstressed and stressed BPA-free thermoplastic resins leached chemicals having significant levels of EA, including one polystyrene (PS), and three Tritan™ resins, the latter reportedly EA-free. Exposure to UV radiation in natural sunlight resulted in an increased release of EA from Tritan™ resins. Triphenyl-phosphate (TPP), an additive used to manufacture some thermoplastic resins such as Tritan™, exhibited EA in both MCF-7 and BG1Luc assays. Ten unstressed or stressed glycol-modified polyethylene terephthalate (PETG), cyclic olefin polymer (COP) or copolymer (COC) thermoplastic resins did not release chemicals with detectable EA under any test condition. Conclusions: This hazard survey study assessed the release of chemicals exhibiting EA as detected by two sensitive, widely used and accepted, human cell line in vitro assays. Four PC replacement resins (Tritan™ and PS) released chemicals having EA. However, ten other PC-replacement resins did not leach chemicals having EA (EA-free-resins). These results indicate that PC-replacement plastic products could be made from EA-free resins (if appropriate EA-free additives are chosen) that maintain advantages of re-usable plastic items (price, weight, shatter resistance) without releasing chemicals having EA that potentially produce adverse health effects on current or future generations.This work was supported by the following NIH/NIEHS grants: R44 ES011469, 01–03 (CZY); 1R43/44 ES014806, 01–03 (CZY); subcontract (CZY, PI) on an NIH Grant 01–03 43/44ES018083-01. This work was also supported by NIH grants to MSD (P42 ES004699), and DJK and SIY (1R43ES018083-01-03, NIEHS 1R44ES019442-01-03 and NIEHS 2R44ES016964-01-03).Neuroscienc

Why do sultanistic regimes arise and persist? A study of government in the republic of Turkmenistan, 1992-2006

This thesis investigates why extreme forms of personal rule arise and endure in the contemporary international system. More particularly, it seeks to answer the puzzle of why the regime of President Saparmurat Niyazov (Turkmenbashi), in the Central Asian republic of Turkmenistan, has paradoxically proven to be one of the region's most stable states between 1992 and 2006, notwithstanding the fact that it is characterised by Niyazov's unchecked personal power, barely functional political institutions, endemic corruption and a pervasive cult of personality. The study develops the theoretical approach most commonly applied to this type of regime and produces an original empirical study of a strategically important gas-rich state that has hitherto received almost no attention from the academic community. Specifically, the thesis engages with two theories of sultanistic regimes advanced in 1990 by H.E. Chehabi and Juan J. Linz. The research findings demonstrate that, while the essential insights of the theories remain valid, they require careful revision and refinement if they are to successfully incorporate postcommunist regimes into their paradigm. The project uses a mixture of interviews, field observation, and primary and secondary documents to answer the research problem. It finds that the structural legacies of the pre Soviet and Soviet period, allied to a favourable strategic context, enabled Niyazov to secure power and sideline potential rivals. The thesis argues that a combination of different domestic control techniques, of which the cult of personality forms an essential part, has been deployed by Niyazov to maintain his position. Taken together, these techniques form a 'disciplinary-symbolic' nexus aimed at preventing the emergence of opposition groups, while simultaneously promoting Niyazov as the sole guarantor of national unity and prosperity. The thesis also explores popular responses to sultanism, concluding that Turkmen adopt a complex and contradictory web of personal strategies in their dealings with the regime, ranging from engagement, accommodation and indifference, through to covert resistance and outright opposition. Finally, the thesis assesses the interaction between sultanistic regimes and external actors. It finds that, far from exposing rulers to greater pressure from the international community, the end of the Cold War actually increased the autonomy of many sultanistic rulers. No longer shackled by the disciplines of superpower patronage, most sultanistic rulers, including Niyazov, have been able to function with minimal constraints on their domestic behaviour

Predictive Context Influences Perceptual Selection during Binocular Rivalry

Prediction may be a fundamental principle of sensory processing: it has been proposed that the brain continuously generates predictions about forthcoming sensory information. However, little is known about how prediction contributes to the selection of a conscious percept from among competing alternatives. Here, we used binocular rivalry to investigate the effects of prediction on perceptual selection. In binocular rivalry, incompatible images presented to the two eyes result in a perceptual alternation between the images, even though the visual stimuli remain constant. If predictive signals influence the competition between neural representations of rivalrous images, this influence should generate a bias in perceptual selection that depends on predictive context. To manipulate predictive context, we developed a novel binocular rivalry paradigm in which rivalrous test images were immediately preceded by a sequence of context images presented identically to the two eyes. One of the test images was consistent with the preceding image sequence (it was the expected next image in the series), and the other was inconsistent (non-predicted). We found that human observers were more likely to perceive the consistent image at the onset of rivalry, suggesting that predictive context biased selection in favor of the predicted percept. This prediction effect was distinct from the effects of adaptation to stimuli presented before the binocular rivalry test. In addition, perceptual reports were speeded for predicted percepts relative to non-predicted percepts. These results suggest that predictive signals related to visual stimulus history exist at neural sites that can bias conscious perception during binocular rivalry. Our paradigm provides a new way to study how prior information and incoming sensory information combine to generate visual percepts