Computing Teichm\"{u}ller Maps between Polygons

By the Riemann-mapping theorem, one can bijectively map the interior of an $n$-gon $P$ to that of another $n$-gon $Q$ conformally. However, (the boundary extension of) this mapping need not necessarily map the vertices of $P$ to those $Q$. In this case, one wants to find the ``best" mapping between these polygons, i.e., one that minimizes the maximum angle distortion (the dilatation) over \textit{all} points in $P$. From complex analysis such maps are known to exist and are unique. They are called extremal quasiconformal maps, or Teichm\"{u}ller maps. Although there are many efficient ways to compute or approximate conformal maps, there is currently no such algorithm for extremal quasiconformal maps. This paper studies the problem of computing extremal quasiconformal maps both in the continuous and discrete settings. We provide the first constructive method to obtain the extremal quasiconformal map in the continuous setting. Our construction is via an iterative procedure that is proven to converge quickly to the unique extremal map. To get to within $\epsilon$ of the dilatation of the extremal map, our method uses $O(1/\epsilon^{4})$ iterations. Every step of the iteration involves convex optimization and solving differential equations, and guarantees a decrease in the dilatation. Our method uses a reduction of the polygon mapping problem to that of the punctured sphere problem, thus solving a more general problem. We also discretize our procedure. We provide evidence for the fact that the discrete procedure closely follows the continuous construction and is therefore expected to converge quickly to a good approximation of the extremal quasiconformal map.Comment: 28 pages, 6 figure

Inferring Unusual Crowd Events From Mobile Phone Call Detail Records

The pervasiveness and availability of mobile phone data offer the opportunity of discovering usable knowledge about crowd behaviors in urban environments. Cities can leverage such knowledge in order to provide better services (e.g., public transport planning, optimized resource allocation) and safer cities. Call Detail Record (CDR) data represents a practical data source to detect and monitor unusual events considering the high level of mobile phone penetration, compared with GPS equipped and open devices. In this paper, we provide a methodology that is able to detect unusual events from CDR data that typically has low accuracy in terms of space and time resolution. Moreover, we introduce a concept of unusual event that involves a large amount of people who expose an unusual mobility behavior. Our careful consideration of the issues that come from coarse-grained CDR data ultimately leads to a completely general framework that can detect unusual crowd events from CDR data effectively and efficiently. Through extensive experiments on real-world CDR data for a large city in Africa, we demonstrate that our method can detect unusual events with 16% higher recall and over 10 times higher precision, compared to state-of-the-art methods. We implement a visual analytics prototype system to help end users analyze detected unusual crowd events to best suit different application scenarios. To the best of our knowledge, this is the first work on the detection of unusual events from CDR data with considerations of its temporal and spatial sparseness and distinction between user unusual activities and daily routines.Comment: 18 pages, 6 figure

Immunotoxicity of Ochratoxin and Citrinin in New Zealand White rabbits

In the present study, the effects of ochratoxin A (OTA), citrinin (CIT) and their combination on the immunological parameters were studied in 6-8 weeks old New Zealand White rabbits at 60 d post-intoxication. Thirty two rabbits were divided into four groups of eight. OTA, CIT and a combination of the two were given at 0.75 mg/kg, 15 mg/kg and 0.75 plus 15 mg/kg, in feed respectively for up to 60 d of the trial. Other fourth group was used as a control, being fed standard toxin free feed. The toxin treated animals showed a signifi cant decline in antibody titres to sheep red blood cells. The reduction in the cell mediated immune response was more signifi cant in the OTA and combination groups as observed in the skin hypersensitivity test and the lymphocyte proliferation assay. The citrinin-treated rabbits failed to show any signifi cant changes following the lymphocyte transformation assay and the delayed type hypersensitivity test. Histologically, the cellular (mononuclear cells) reaction in the skin in the treated groups was comparatively lesser than that of the control group. Thus, the present study in rabbits indicated signifi cantly lower humoral and cellular immune responses in the OTA and combination groupsThe authors would like to acknowledge the help extended by the Director of the IVRI and the Head of the Division of Pathology in the execution of this research. This study was financially supported in part by the NATP-CGP (ICAR) Project No. II/221.Kumar, M.; Dwivedi, P.; Sharma, A.; Telang, A.; Patil, R.; Singh, N. (2010). Immunotoxicity of Ochratoxin and Citrinin in New Zealand White rabbits. World Rabbit Science. 16(1). http://hdl.handle.net/10251/851416

Decreased dopamine activity predicts relapse in methamphetamine abusers.

Studies in methamphetamine (METH) abusers showed that the decreases in brain dopamine (DA) function might recover with protracted detoxification. However, the extent to which striatal DA function in METH predicts recovery has not been evaluated. Here we assessed whether striatal DA activity in METH abusers is associated with clinical outcomes. Brain DA D2 receptor (D2R) availability was measured with positron emission tomography and [(11)C]raclopride in 16 METH abusers, both after placebo and after challenge with 60 mg oral methylphenidate (MPH) (to measure DA release) to assess whether it predicted clinical outcomes. For this purpose, METH abusers were tested within 6 months of last METH use and then followed up for 9 months of abstinence. In parallel, 15 healthy controls were tested. METH abusers had lower D2R availability in caudate than in controls. Both METH abusers and controls showed decreased striatal D2R availability after MPH and these decreases were smaller in METH than in controls in left putamen. The six METH abusers who relapsed during the follow-up period had lower D2R availability in dorsal striatum than in controls, and had no D2R changes after MPH challenge. The 10 METH abusers who completed detoxification did not differ from controls neither in striatal D2R availability nor in MPH-induced striatal DA changes. These results provide preliminary evidence that low striatal DA function in METH abusers is associated with a greater likelihood of relapse during treatment. Detection of the extent of DA dysfunction may be helpful in predicting therapeutic outcomes

GoCo: planning expressive commitment protocols

Acknowledgements We gratefully thank those who shared their code with us. Special thanks to Ugur Kuter. We thank the anonymous reviewers, and also acknowledge with gratitude the reviewers at ProMAS’11, AAMAS’13, AAAI’13, and AAMAS’15, where preliminary parts of this work appeared. FM thanks the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for the support within process numbers 306864/2013-4 under the PQ fellowship and 482156/2013-9 under the Universal project programs. NYS acknowledges support of the AUB University Research Board Grant Number 102853 and the OSB Grant OFFER_C1_2013_2014.Peer reviewe