One-eyed stereo: a general approach to modeling 3-d scene geometry

A single two-dimensional image is an ambiguous representation of the three-dimensional world?many different scenes could have produced the same image?yet the human visual system is ex-tremely successful at recovering a qualitatively correct depth model from this type of representation. Workers in the field of computational vision have devised a number of distinct schemes that attempt to emulate this human capability; these schemes are collectively known as ``shape from...' methods (e.g., shape from shading, shape from texture, or shape from contour). In this paper we contend that the distinct assumptions made in each of these schemes is tantamount to providing a second (virtual) image of the original scene, and that each of these approaches can be translated into a conventional stereo formalism. In particular, we show that it is frequently possible to structure the problem as one of recovering depth from a stereo pair consisting of the supplied perspective image (the original image) and an hypothesized orthographic image (the virtual image). We present a new algorithm of the form required to accomplish this type of stereo reconstruction task.     

The Solubility of Some Azafullerene Derivatives

Abstract

Several fulleroaziridines, azafulleroids and chiral cage-opened ketolactams were synthesized from alkyl azides and C₆₀. Their solubility in various solvents was evaluated by HPLC. It depends both on the starting azide and the linker group. Moreover, the formation of two sp³ carbons (entries 2) and then of carbonyl derivatives (entries 3) induces a decrease of the polarizability of the C₆₀ moiety and an enhancement of the solubility in lipophilic solvents.     

Thyroid cancers

We have analysed factors that influenced on the patient survival in 195 cases of thyroid cancer. The survival is essentially influenced by the histology, the papillary forms (survival after 15 years: 83.1-93%) and follicular cancers (survival after 15 years: 84-94%) having an excellent evolution. The non-differentiated and mixed cancers have a very severe prognosis that is independent of the complex therapy that have been used (survival after 5 years: 17.1% in non-differentiated forms and 32.5% in mixed ones). The prognosis is better in subjects under the age of 45 and in female subjects. The cancers in the 1-st and 2-nd stage of tumor extension have a better evolution that those in the 3-rd stage. In differentiated cancers, the total or subtotal thyroidectomy followed by radioiodine administration determine the best survival.     

Hydrolysis of methyl α- and β-D-glucopyranosides in the presence of a dealuminated H-Y faujasite

Hydrolysis of methyl α- and β-D-glucopyranosides was performed in the presence of protonic-form zeolites such as a dealuminated Y-faujasite with a Si/Al ratio of 15, at temperatures ranging between 100 and 150°C, and in water as the solvent. The β/α ratio for the hydrolysis reaction rates was found to be equal to 5–6, whereas a ratio of 2–3 was reported in the literature for the homogeneous reaction. The observed higher β/α ratio is proposed to result from the reinforcement of stereoelectronic effects which were shown to apply in reactions taking place on the surface of a solid. Those effects operate in a classical manner on a molecular standpoint, but they are reinforced due to the favorable interaction of oxygen electron lone pairs with the electron-deficient species present on the surface of the solid, protonic species in the case of zeolites. This revised version was published online in August 2006 with corrections to the Cover Date.     

Heat transfer in envelopes made of porous network materials

Presented here are results of combined laboratory and numerical experiments on heat transfer in envelope porous network materials. It is shown that the discrepancies between the relationship for internal heat transfer and the experimental data on volumetric heat transfer at small Reynolds numbers are associated with the effect of heat conductivity along the cooling gas flow on the temperature field.     

Retina enhanced SURF descriptors for spatio-temporal concept detection

This paper proposes to investigate the potential benefit of the use of low-level human vision behaviors in the context of high-level semantic concept detection. A large part of the current approaches relies on the Bag-of-Words (BoW) model, which has proven itself to be a good choice especially for object recognition in images. Its extension from static images to video sequences exhibits some new problems to cope with, mainly the way to use the temporal information related to the concepts to detect (swimming, drinking...). In this study, we propose to apply a human retina model to preprocess video sequences before constructing the State-Of-The-Art BoW analysis. This preprocessing, designed in a way that enhances relevant information, increases the performance by introducing robustness to traditional image and video problems, such as luminance variation, shadows, compression artifacts and noise. Additionally, we propose a new segmentation method which enables a selection of low-level spatio-temporal potential areas of interest from the visual scene, without slowing the computation as much as a high-level saliency model would. These approaches are evaluated on the TrecVid 2010 and 2011 Semantic Indexing Task datasets, containing from 130 to 346 high-level semantic concepts. We also experiment with various parameter settings to check their effect on performance.     

Impact of age at onset of cannabis use on cannabis dependence and driving under the influence in the United States

Background and aims

There is growing evidence that driving under the influence of cannabis is associated with a higher risk of motor vehicle crash. Cannabis dependence has been reported to be associated with a three-fold increased risk of motor vehicle crash. The impact of the age at onset of cannabis use on the risk of both cannabis dependence and driving under the influence of cannabis has not been evaluated so far.

Methods

Data were drawn from the 2001–2002 National Epidemiological Survey on Alcohol and Related Conditions (NESARC), a survey of 43,093 adults aged 18 years and older. We limited our analyses to the sample of participants who reported having ever used cannabis (n = 8172), of whom 8068 had a known age at onset of cannabis use.

Results

Of the 8068 participants included, 5.15% reported having driven under the influence of cannabis. Among those, only a minority (14.46%) were diagnosed with cannabis dependence.Compared to those who start using cannabis at age 21 years or after, participants who used cannabis before the age of 14 years were 4 times more likely to have a history of cannabis dependence and 3 times more likely to reported having driven under the influence of cannabis. An inverse relationship between the age at onset of cannabis use and driving under the influence and risk of cannabis dependence was found.

Conclusions

Starting to smoke cannabis younger than 21 years is associated with both cannabis dependence and driving under the influence of cannabis.     

The Solubility of Some Azafullerene Derivatives

Several fulleroaziridines, azafulleroids and chiral cage-opened ketolactams were synthesized from alkyl azides and C₆₀. Their solubility in various solvents was evaluated by HPLC. It depends both on the starting azide and the linker group. Moreover, the formation of two sp³ carbons (entries 2) and then of carbonyl derivatives (entries 3) induces a decrease of the polarizability of the C₆₀ moiety and an enhancement of the solubility in lipophilic solvents.