Graphical functions in parametric space

Graphical functions are positive functions on the punctured complex plane $\mathbb{C}\setminus\{0,1\}$ which arise in quantum field theory. We generalize a parametric integral representation for graphical functions due to Lam, Lebrun and Nakanishi, which implies the real analyticity of graphical functions. Moreover we prove a formula that relates graphical functions of planar dual graphs.Comment: v2: extended introduction, minor changes in notation and correction of misprint

The threshold for jigsaw percolation on random graphs

Jigsaw percolation is a model for the process of solving puzzles within a social network, which was recently proposed by Brummitt, Chatterjee, Dey and Sivakoff. In the model there are two graphs on a single vertex set (the `people' graph and the `puzzle' graph), and vertices merge to form components if they are joined by an edge of each graph. These components then merge to form larger components if again there is an edge of each graph joining them, and so on. Percolation is said to occur if the process terminates with a single component containing every vertex. In this note we determine the threshold for percolation up to a constant factor, in the case where both graphs are Erd\H{o}s--R\'enyi random graphs.Comment: 13 page

The hormonal Zeitgeber melatonin: role as a circadian modulator in memory processing

The neuroendocrine substance melatonin is a hormone synthesized rhythmically by the pineal gland under the influence of the circadian system and alternating light/dark cycles. Melatonin has been shown to have broad applications, and consequently becoming a molecule of great controversy. Undoubtedly, however, melatonin plays an important role as a time cue for the endogenous circadian system. This review focuses on melatonin as a regulator in the circadian modulation of memory processing. Memory processes (acquisition, consolidation, and retrieval) are modulated by the circadian system. However, the mechanism by which the biological clock is rhythmically influencing cognitive processes remains unknown. We also discuss, how the circadian system by generating cycling melatonin levels can implant information about daytime into memory processing, depicted as day and nighttime differences in acquisition, memory consolidation and/or retrieval

Adverse selection and the economic limits of market substitution: An application to e-commerce and traditional trade in used cars

Adverse selection induces economic limits to market substitution. If quality uncertainty persists in both internet and traditional marketplaces, a second-best equilibrium with parallel market segments may arise. Positive trade in parallel segments implies that the information cost advantage of one marketplace is exactly offset by a more severe adverse selection problem associated with non-observable quality variables. The electronic marketplace providing dominant search means contains all segments, while the traditional market may lack some segments. These missing segments are characterized by low quality expectations given the vector of advertised quality signals. The analytic results are confirmed by an empirical investigation of used-car trade. Thus, the study also provides an estimate of the price differential between the electronic and the traditional marketplace

Time and price impact of a trade: A structural approach

Dufour and Engle (2000) have shown that the duration between subsequent trade events carries informational content with respect to the evolution of the fundamental asset value. Their analysis supports the notion that no trade means no information derived from Easley and O'Hara's (1992) microstructure model. This paper revisits the role of time in measuring the price impact of trades using a structural model and provides challenging new evidence. For that purpose we extend Madhavan et al.'s (1997) model to account for time varying trading intensities. Our results confirm predictions from strategic trading models put forth by Parlour (1998) and Foucault (1999) in which short durations between trades are not related to the processing of private information. Instead, they are caused by strategic trading of impatient non-informed agents who use market orders more intensively when order book liquidity is high

Single Incision Laparoscopic Splenectomy in a 5-Year-Old With Hereditary Spherocytosis

Laparoscopic splenectomy in a pediatric patient was performed through a single umbilical incision by using 3 ports

PPS: Privacy-preserving statistics using RFID tags

As RFID applications are entering our daily life, many new security and privacy challenges arise. However, current research in RFID security focuses mainly on simple authentication and privacy-preserving identication. In this paper, we discuss the possibility of widening the scope of RFID security and privacy by introducing a new application scenario. The suggested application consists of computing statistics on private properties of individuals stored in RFID tags. The main requirement is to compute global statistics while preserving the privacy of individual readings. PPS assures the privacy of properties stored in each tag through the combination of homomorphic encryption and aggregation at the readers. Re-encryption is used to prevent tracking of users. The readers scan tags and forward the aggregate of their encrypted readings to the back-end server. The back-end server then decrypts the aggregates it receives and updates the global statistics accordingly. PPS is provably privacypreserving. Moreover, tags can be very simple since they are not required to perform any kind of computation, but only to store data