Ensenada Center for Scientific Research and Higher Education

About: Ensenada Center for Scientific Research and Higher Education is a facility organization based out in Ensenada, Mexico. It is known for research contribution in the topics: Population & Nonlinear system. The organization has 1934 authors who have published 3733 publications receiving 63115 citations.

Evolutionary learning of local descriptor operators for object recognition

Abstract: Nowadays, object recognition is widely studied under the paradigm of matching local features. This work describes a genetic programming methodology that synthesizes mathematical expressions that are used to improve a well known local descriptor algorithm. It follows the idea that object recognition in the cerebral cortex of primates makes use of features of intermediate complexity that are largely invariant to change in scale, location, and illumination. These local features have been previously designed by human experts using traditional representations that have a clear, preferably mathematically, well-founded definition. However, it is not clear that these same representations are implemented by the natural system with the same structure. Hence, the possibility to design novel operators through genetic programming represents an open research avenue where the combinatorial search of evolutionary algorithms can largely exceed the ability of human experts. This paper provides evidence that genetic programming is able to design new features that enhance the overall performance of the best available local descriptor. Experimental results confirm the validity of the proposed approach using a widely accept testbed and an object recognition application.

The Rab GTPase YPT-1 associates with Golgi cisternae and Spitzenkörper microvesicles in Neurospora crassa

Abstract: Vesicle traffic involves budding, transport, tethering and fusion of vesicles with acceptor membranes. GTP-bound small Rab GTPases interact with the membrane of vesicles, promoting their association with other factors before their subsequent fusion. Filamentous fungi contain at their hyphal apex the Spitzenkorper (Spk), a multivesicular structure to which vesicles concentrate before being redirected to specific cell sites. The regulatory mechanisms ensuring the directionality of the vesicles that travel to the Spk are still unknown. Hence, we analyzed YPT-1, the Neurospora crassa homologue of Saccharomyces cerevisiae Ypt1p (Rab1), which regulates different secretory pathway events. Laser scanning confocal microscopy revealed fluorescently tagged YPT-1 at the Spk and putative Golgi cisternae. Co-expression of YPT-1 and predicted post-Golgi Rab GTPases showed YPT-1 confined to the Spk microvesicular core, while SEC-4 (Rab8) and YPT-31 (Rab11) occupied the Spk macrovesicular peripheral layer, suggesting that trafficking and organization of macro and microvesicles at the Spk are regulated by distinct Rabs. Partial colocalization of YPT-1 with USO-1 (p115) and SEC-7 indicated the additional participation of YPT-1 at early and late Golgi trafficking steps.

On minmax filtering over discrete-continuous observations

Abstract: This paper presents the minmax filtering problem for a state of a dynamic system under uncertainty conditions over discrete-continuous observations. The solution of the problem is based on the previously derived minmax filtering equations over continuous observations. Some mathematical tools concerning the problem are considered. >

Emotional awareness in collaborative systems

Abstract: Emotions play an important role in human interaction. Both, our own emotional state and our perception of that of others with which we collaborate influence the outcome of cooperative work. With the growing interest in providing computational support for the recognition and representation of emotions, there is a clear interest in adding such facilities to groupware systems and to evaluate the positive and negative effects of using this additional channel of communication. We discuss the issues involved in supporting a new type of collaborative awareness in groupware, namely, emotional awareness. We also present two emotion-based sample applications, and discussion to further motivate work in this area within the collaborative community.

Demography and biomass of the seagrass Zostera marina in a Mexican Coastal Lagoon

Abstract: From January 1987 to February 1988 the annual biomass cycle and demography of the seagrass Zostera marina were assessed in San Quintin Bay, a shallow coastal lagoon on the Pacific coast of Baja California, Mexico. Shoot density and aboveground biomass were sampled monthly along two intertidal transects parallel to the shore. Belowground biomass was sampled every 2 mo. Shoot density differed between transects, ranging from 929±71 (SE) in July to 279 ±80 shoots m−2 in December, at the deeper transect (I). At the shallow transect (II) there was not a significant difference through time, and a mean of 737 shoots m−2 was calculated. Lateral shoots were present year round and represented between 1% and 30% of total density at transect I and between 3% and 25% at transect II. Reproductive shoots were present from March to September at both transects, with a density range of 77±28 shoots m−2 (March) to 9±3 shoots m−2 (September), and represented 5% of total shoot density. Neither aboveground biomass nor LAI (Leaf Area Index) differed between transects, with values ranging between 77±14.5 g dry wt m−2 (October 1987) and 13±2.4 g dry wt m−2 (February 1988) for aboveground biomass, and between 0.6±0.2 m2 leves m−2 substrate (January) and 2.7±0.3 m2 leaves m−2 substrate (September) for LAI. Neither root biomass nor rhizome biomass differed between transects, or as a function of time; the mean value for roots was 17 g dry wt m−2 and for rhizomes 29 g dry wt m−2. Belowground biomass represented 54% of total biomass. We found a significant correlation between aboveground biomass and LAI (r=0.949 for transect I, and 0.926 for transect II) as well as between total biomass (aboveground and belowground) and LAI (r=0.814), which allows us to consider using LAI as a predictor of these variables. Biomass changes were related to changes in shoot weight (r=0.676 at transect I; 0.582 at transect II), more than to changes in shoot number. Water temperature was found to be the driver of biomass changes in the aboveground compartment.