A Pilot Search for Population III Supernova Candidates in the Spitzer/IRAC Dark Field

We have undertaken a systematic search for candidate supernovae from high-redshift Population III stars in a field that has been observed with repeated imaging on a cadence of 2-3 weeks over a 2.2 year baseline, the Spitzer/IRAC Dark Field. The individual epochs reach a typical 5-sigma depth of 1 uJy in IRAC Channel 1 (3.6 um). Requiring a minimum of four epochs coverage, the total effective area searched is 214 sq arcminutes. The unprecedented depth and multi-epochal nature of these data make it ideal for a first foray to detect transient objects which may be candidate luminous Pair Instability Supernovae from the primordial-metallicity first stars. The search was conducted over a broad range of timescales, allowing for different durations of the putative candidates' light curve plateau phases. All candidates were vetted by inspection of the Spitzer imaging data, as well as deep HST/ACS F814W imaging available over the full field. While many resolved-source objects were found with Spitzer variability, no transient objects could plausibly be identified as high-redshift supernovae candidates. The resulting 95% confidence level upper limit is 23/sq deg/yr, for sources with plateau timescales under 400/(1+z) days and brightnesses above ~1 uJy.Comment: ApJL, in pres

Fungal entomopathogens: new insights on their ecology

An important mechanism for insect pest control should be the use of fungal entomopathogens. Even though these organisms have been studied for more than 100 y, their effective use in the field remains elusive. Recently, however, it has been discovered that many of these entomopathogenic fungi play additional roles in nature. They are endophytes, antagonists of plant pathogens, associates with the rhizosphere, and possibly even plant growth promoting agents. These findings indicate that the ecological role of these fungi in the environment is not fully understood and limits our ability to employ them successfully for pest management. In this paper, we review the recently discovered roles played by many entomopathogenic fungi and propose new research strategies focused on alternate uses for these fungi. It seems likely that these agents can be used in multiple roles in protecting plants from pests and diseases and at the same time promoting plant growth

Different paths to the modern state in Europe: the interaction between domestic political economy and interstate competition

Theoretical work on state formation and capacity has focused mostly on early modern Europe and on the experience of western European states during this period. While a number of European states monopolized domestic tax collection and achieved gains in state capacity during the early modern era, for others revenues stagnated or even declined, and these variations motivated alternative hypotheses for determinants of fiscal and state capacity. In this study we test the basic hypotheses in the existing literature making use of the large date set we have compiled for all of the leading states across the continent. We find strong empirical support for two prevailing threads in the literature, arguing respectively that interstate wars and changes in economic structure towards an urbanized economy had positive fiscal impact. Regarding the main point of contention in the theoretical literature, whether it was representative or authoritarian political regimes that facilitated the gains in fiscal capacity, we do not find conclusive evidence that one performed better than the other. Instead, the empirical evidence we have gathered lends supports to the hypothesis that when under pressure of war, the fiscal performance of representative regimes was better in the more urbanized-commercial economies and the fiscal performance of authoritarian regimes was better in rural-agrarian economie

Hunting bats adjust their echolocation to receive weak prey echoes for clutter reduction

This study was funded by the Carlsberg Semper Ardens grant to P.T.M. and by the Emmy Noether program of the Deutsche Forschungsgemeinschaft (DFG; German Research Foundation, grant no. 241711556) to H.R.G. All experiments were carried out under the following licenses: 721/12.06.2017, 180/07.08.2018, and 795/17.05.2019.How animals extract information from their surroundings to guide motor patterns is central to their survival. Here, we use echo-recording tags to show how wild hunting bats adjust their sensory strategies to their prey and natural environment. When searching, bats maximize the chances of detecting small prey by using large sensory volumes. During prey pursuit, they trade spatial for temporal information by reducing sensory volumes while increasing update rate and redundancy of their sensory scenes. These adjustments lead to very weak prey echoes that bats protect from interference by segregating prey sensory streams from the background using a combination of fast-acting sensory and motor strategies. Counterintuitively, these weak sensory scenes allow bats to be efficient hunters close to background clutter broadening the niches available to hunt for insects.Publisher PDFPeer reviewe

Glutamate Decarboxylases in Nonneural Cells of Rat Testis and Oviduct: Differential Expression of GAD 65 and GAD 67

Γ-Aminobutyric acid (GABA) and its synthetic enzyme, glutamate decarboxylase (GAD), are not limited to the nervous system but are also found in nonneural tissues. The mammalian brain contains at least two forms of GAD (GAD 67 and GAD 65 ), which differ from each other in size, sequence, immunoreactivity, and their interaction with the cofactor pyridoxal 5′-phosphate (PLP). We used cDNAs and antibodies specific to GAD 65 and GAD 67 to study the molecular identity of GADs in peripheral tissues. We detected GAD and GAD mRNAs in rat oviduct and testis. In oviduct, the size of GAD, its response to PLP, its immunoreactivity, and its hybridization to specific RNA and DNA probes all indicate the specific expression of the GAD 65 gene. In contrast, rat testis expresses the GAD 67 gene. The GAD in these two reproductive tissues is not in neurons but in nonneural cells. The localization of brain GAD and GAD mRNAs in the mucosal epithelial cells of the oviduct and in spermatocytes and spermatids of the testis shows that GAD is not limited to neurons and that GABA may have functions other than neurotransmission.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66211/1/j.1471-4159.1992.tb09763.x.pd

State Capacity and Long-Run Economic Performance

Almost final version of the paperWe present new evidence about the long-run relationship between state capacity { the scal and administrative power of states { and economic performance. Our database is novel and spans 11 European countries and 4 centuries from the Old Regime to World War I. We argue that national governments undertook two political transformations over this period: fi scal centralisation and limited government. We fund a signifi cant direct relationship between fiscal centralisation and economic growth. Furthermore, we fi nd that an increase in the state's capacity to extract greater tax revenues was one mechanism through which both political transformations improved economic performance. Our analysis shows systematic evidence that state capacity is an important determinant of long-run economic growth

KLF2 Is a Novel Transcriptional Regulator of Endothelial Proinflammatory Activation

The vascular endothelium is a critical regulator of vascular function. Diverse stimuli such as proinflammatory cytokines and hemodynamic forces modulate endothelial phenotype and thereby impact on the development of vascular disease states. Therefore, identification of the regulatory factors that mediate the effects of these stimuli on endothelial function is of considerable interest. Transcriptional profiling studies identified the Kruppel-like factor (KLF)2 as being inhibited by the inflammatory cytokine interleukin-1β and induced by laminar shear stress in cultured human umbilical vein endothelial cells. Overexpression of KLF2 in umbilical vein endothelial cells robustly induced endothelial nitric oxide synthase expression and total enzymatic activity. In addition, KLF2 overexpression potently inhibited the induction of vascular cell adhesion molecule-1 and endothelial adhesion molecule E-selectin in response to various proinflammatory cytokines. Consistent with these observations, in vitro flow assays demonstrate that T cell attachment and rolling are markedly attenuated in endothelial monolayers transduced with KLF2. Finally, our studies implicate recruitment by KLF2 of the transcriptional coactivator cyclic AMP response element–binding protein (CBP/p300) as a unifying mechanism for these various effects. These data implicate KLF2 as a novel regulator of endothelial activation in response to proinflammatory stimuli

Allocation under dictatorship : research in Stalin’s archives

We survey recent research on the Soviet economy in the state, party, and military archives of the Stalin era. The archives have provided rich new evidence on the economic arrangements of a command system under a powerful dictator including Stalin’s role in the making of the economic system and economic policy, Stalin’s accumulation objectives and the constraints that limited his power to achieve them, the limits to administrative allocation, the information flows and incentives that governed the behavior of economic managers, the scope and significance of corruption and market-oriented behavior, and the prospects for economic reform

買主ノ物品受取ノ義務ヲ論ズ

Markets are central to modern society, so their failures can be devastating. Here, we examine a prominent failure: price bubbles. Bubbles emerge when traders err collectively in pricing, causing misfit between market prices and the true values of assets. The causes of such collective errors remain elusive. We propose that bubbles are affected by ethnic homogeneity in the market and can be thwarted by diversity. In homogenous markets, traders place undue confidence in the decisions of others. Less likely to scrutinize others’ decisions, traders are more likely to accept prices that deviate from true values. To test this, we constructed experimental markets in Southeast Asia and North America, where participants traded stocks to earn money. We randomly assigned participants to ethnically homogeneous or diverse markets. We find a marked difference: Across markets and locations, market prices fit true values 58% better in diverse markets. The effect is similar across sites, despite sizeable differences in culture and ethnic composition. Specifically, in homogenous markets, overpricing is higher as traders are more likely to accept speculative prices. Their pricing errors are more correlated than in diverse markets. In addition, when bubbles burst, homogenous markets crash more severely. The findings suggest that price bubbles arise not only from individual errors or financial conditions, but also from the social context of decision making. The evidence may inform public discussion on ethnic diversity: it may be beneficial not only for providing variety in perspectives and skills, but also because diversity facilitates friction that enhances deliberation and upends conformity