Biological Sciences

Since only 12.6% of the Brazilian Araucaria Forest remains and timber tree monocultures are expanding, biological invasion is a potential threat to the conservation of natural forest remnants. Here, we test (1) the susceptibility of Araucaria Forest to invasion by Pinus taeda and Eucalyptus saligna, (2) the efficiency of different mechanisms controlling the early establishment of these two exotic timber tree species, and (3) the potential of the native timber tree Araucaria angustifolia to establish successfully in ecologically-managed monocultures of Araucaria, Pinus and Eucalyptus. In Araucaria Forest, more than a thousand Pinus seeds landed annually in a hectare; however, experimentally exposed seeds were 100% removed in only 6 days. Furthermore, all experimentally transplanted seedlings of Pinus taeda and Eucalyptus saligna died in less than a year in Araucaria Forest, but not in the monocultures. Correlative evidence suggests that this mortality was associated to plant community richness, plant abundance, and soil fertility. Araucaria angustifolia, in contrast, showed an establishment success in ecologically-managed tree monocultures as high as that exhibited in its natural habitat. The current resistance of Araucaria Forest to invasion by exotic timber trees is good news for the conservation of Araucaria Forest remnants and for its keystone species. The understanding of the mechanisms providing such resistance against invasion points towards management tools for minimizing future threats.

Hand gestures and speech comprise the most important modalities of human to human interaction. Motivated by this, there has been a considerable interest in incorporating these modalities for “natural” human-computer interaction (HCI) particularly within virtual ...

We present a new model for the perceptual reasoning involved in hand/eye coordination, and we show how this model can be developed into a control mechanism for a robot manipulator with a visual sensor. This new approach overcomes the high computational ...

Abstract Despite recent advances in vision-based gesture recognition, its application remains largely limited to pre-defined gestures. A key reason for this is the low recognition rates for “natural” gesticulation. Some attempts have been made in using speech cues to improve gesture recognition, e.g., keyword-gesture co-analysis. Such “semantic-level” multimodal schemes,inherit the complexity ,of natural language understanding and are not suitable for

The classical presentation of intussusception consisting of severe abdominal pain, bloody stool, and a palpable abdominal mass leads to the correct diagnosis in majority of the patients. However, an atypical presentation often results in a delayed diagnosis as is commonly seen in nonischemic intussusception. The nonischemic intussusception is a distinct clinical entity that is characterized by a long history of less severe symptoms commonly noticed in older children. The incidence of diarrhea in this group is higher than in the acute variety of intussusception. This variant of intussusception requires a high degree of suspicion for the diagnosis in atypical clinical presentation. The present study summarises our experience treating 31 such cases of nonischemic intussusception during a period of 25 years from 1966 to July 1990.

Rats fed rice bran oil at 10% level for a period of eight weeks showed significantly lower levels of total cholesterol, low density lipoprotein and very low density lipoprotein cholesterol, both on cholesterol-containing and cholesterol-free diets. High density lipoprotein cholesterol was increased but triglyceride showed a decrease that was not statistically significant. Liver cholesterol and liver triglycerides were also reduced. Fecal excretion of neutral sterols and bile acids was increased after ingestion of rice bran oil.

There has been a considerable interest in using active vision for various applications. This interest is primarily because active vision can enhance machine vision capabilities by dynamically changing the camera parameters based on the content of the scene. An important issue in active vision is that of representing 3D targets in a manner that is invariant to changing camera configurations. This paper addresses this representation issue for a robotic active vision system. An efficient Vector Associative Map (VAM)-based learning scheme is proposed to learn a joint-based representation. Computer simulations and experiments are first performed to evaluate the effectiveness of this scheme using the University of Illinois Active Vision System (UIAVS). The invariance property of the learned representation is then exploited to develop several robotic applications. These include, detecting moving targets, saccade control, planning saccade sequences and controlling a robot manipulator.