The evolution of different neuronal control structures for autonomous agents

The use of evolutionary methods to generate controllers for real-world autonomous agents has attracted recent attention. Most of the pertinent research has employed genetic algorithms or variations thereof. Recent research has indicated that the presence of epistasis drastically slows down genetic algorithms. For this reason, this paper uses a different evolutionary method, evolution strategies, for the evolution of various (complex) neuronal control architectures for mobile robots inspired by Braitenberg vehicles. In these experiments, the evolution strategy accelerates the development process by more than an order of magnitude (a few hours compared to more than two days). Furthermore, the evolution strategy yields the same efficacy when applied to receptive-field controllers that require many more parameters than Braitenberg controllers. This dramatic speedup is very important, since the development process is to be done in real robots.     

Capture of genomic and T-DNA sequences during double-strand break repair in somatic plant cells

To analyze genomic changes resulting from double-strand break (DSB) repair, transgenic tobacco plants were obtained that carried in their genome a restriction site of the rare cutting endonuclease I-SceI within a negative selectable marker gene. After induction of DSB repair via Agrobacterium-mediated transient expression of I-SceI, plant cells were selected that carried a loss-of-function phenotype of the marker. Surprisingly, in addition to deletions, in a number of cases repair was associated with the insertion of unique and repetitive genomic sequences into the break. Thus, DSB repair offers a mechanism for spreading different kinds of sequences into new chromosomal positions. This may have evolutionary consequences particularly for plants, as genomic alterations occurring in meristem cells can be transferred to the next generation. Moreover, transfer DNA (T-DNA), carrying the open reading frame of I-SceI, was found in several cases to be integrated into the transgenic I-SceI site. This indicates that DSB repair also represents a pathway for the integration of T-DNA into the plant genome.     

Lactose handling by women with lactose malabsorption is improved during pregnancy

OBJECTIVE: To evaluate lactose handling among women in late pregnancy and post partum to determine whether lactose handling is altered in pregnancy. DESIGN: Prospective study of lactose intolerance among pregnant women with and without lactose malabsorption. SETTING: Gastroenterology service of the Sir Mortimer B. Davis-Jewish General Hospital, Montreal. PATIENTS: Thirty-three pregnant women, of whom 18 had lactose malabsorption, 12 did not and 3 were excluded. OUTCOME MEASURES: Lactose breath hydrogen (BH2) concentration after ingestion of lactose or lactulose; comparison before and after delivery of area under the curve (AUC) for lactose, oral-cecal transit time (OCTT) for lactulose, lactose-BH2-derived transit time and estimated dietary lactose consumption. RESULTS: After weaning (at a median time of 9 months after delivery), 28 of the women returned for follow-up. Of the 12 who could absorb lactose before delivery, 4 could no longer absorb lactose. Of the other 16 women, lactose intolerance worsened in 12, remained the same in 2 and improved in 2. The AUC was greater (p < 0.005), the maximal BH2 concentration was higher (p = 0.004) and the number of women whose BH2 concentration peaked was fewer (p < 0.025) post partum than before delivery. The women's symptoms during and after lactose BH2 tests were also greater post partum. The OCTT (based on the lactulose BH2 test) was shorter post partum (p = 0.001). Transit time derived from lactose BH2 tests was also shorter, but not significantly so. The OCTT was not inversely correlated with the change in AUC before and after delivery, but the lactose-BH2-derived transit time was inversely correlated. Pregnant women consumed more lactose before delivery than afterward (p < 0.004). CONCLUSIONS: Women with lactose malabsorption handle lactose better than usual in late pregnancy. Slow intestinal transit and bacterial adaptation to increased lactose intake may be primarily responsible.     

LFA-1 interaction with ICAM-1 and ICAM-2 regulates Th2 cytokine production

The role of CD28/B7 and LFA-1/ICAM costimulation in proliferation and Th1/Th2 differentiation of naive CD4+ T cells was addressed using T cells from DO11.10 TCR transgenic mice stimulated by dendritic cells. The blockade of either CD28/B7 or LFA-1/ICAM interactions partially inhibited T cell proliferation. By comparison, blocking CD28/B7 costimulation inhibited IL-4 and IL-5 (Th2 cytokine) production, whereas blocking LFA-1/ICAM-1 or LFA-1/ICAM-2 led to a significant increase (15- to 40-fold) of Th2 cytokines. The combination of anti-ICAM-1 and anti-ICAM-2 mAbs had a synergistic effect with a 100- to 1000-fold increase of Th2 cytokine production. Thus, these two costimulatory pathways have opposing roles in the regulation of Th2 development.     

Implantation of electromagnetic ossicular replacement device

Semi-implantable hearing aids consisting of permanent middle ear implanted magnet, either partial ossicular replacement prostheses (PORP's) or total ossicular replacement prostheses (TORP's) driven by an electromagnet placed in the ear canal have been tested on six patients undergoing surgery for chronic otitis. The surgical and audiological problems are described. The audiological results were excellent in all six cases. A functional gain of 40-70 dB can be obtained for entire frequency range of the audiogram.     

Quick-VDR: out-of-core view-dependent rendering of gigantic models

We present a novel approach for interactive view-dependent rendering of massive models. Our algorithm combines view-dependent simplification, occlusion culling, and out-of-core rendering. We represent the model as a clustered hierarchy of progressive meshes (CHPM). We use the cluster hierarchy for coarse-grained selective refinement and progressive meshes for fine-grained local refinement. We present an out-of-core algorithm for computation of a CHPM that includes cluster decomposition, hierarchy generation, and simplification. We introduce novel cluster dependencies in the preprocess to generate crack-free, drastic simplifications at runtime. The clusters are used for LOD selection, occlusion culling, and out-of-core rendering. We add a frame of latency to the rendering pipeline to fetch newly visible clusters from the disk and avoid stalls. The CHPM reduces the refinement cost of view-dependent rendering by more than an order of magnitude as compared to a vertex hierarchy. We have implemented our algorithm on a desktop PC. We can render massive CAD, isosurface, and scanned models, consisting of tens or a few hundred million triangles at 15-35 frames per second with little loss in image quality.     

A fortran IV program which determines that region of a polygon within a polygonal boundary

An algorithm is presented to determine that portion of an arbitrary polygonal region which is interior to an arbitrary polygonal boundary. The only restriction imposed on the polygons involved is that the region common to both consists of just a single contiguous region. This will hold, for instance, if the polygonal region is relatively small compared to the boundary as would be the situation in most geoscience applications. In particular, the algorithm does not require convexity on the part of either polygon.     

Oxidized phospholipids, isolevuglandins, and atherosclerosis

Autoxidation of polyunsaturated phosphatidylcholines (PCs) generates isolevuglandins (isoLGs) through rearrangements of isoprostanoid endoperoxides. Within seconds, isoLGs are sequestered by covalent adduction with proteins. Murine plasma isoLG-protein levels increased at least 2.5-fold in response to inflammation. IsoLG-protein adducts accumulate in vivo providing a convenient dosimeter of oxidative stress. Elevated blood isoLG-protein levels present in atherosclerosis (AS) patients point to an independent defect that is not associated with total cholesterol levels, which results in an abnormally high level of oxidative injury in AS. Protein adduction and cross-linking caused by isoLGs can obstruct protein function. For example, it interferes with proteosomal degradation of proteins and, consequently, may result in apoptotic death of smooth muscle cells and destabilization of atherosclerotic plaques. Phospholipid autoxidation also generates biologically active oxidatively truncated PCs through fragmentation of dihydroperoxydienes that can be promoted by alpha-tocopherol. The oxidatively truncated PCs in oxidized low-density lipoprotein (oxLDL) contribute to the etiology of AS by inhibiting enzymatic activities required for normal processing of oxLDL by macrophages. They promote interactions of monocytes with endothelial cells that may foster migration of monocytes into the subendothelial space. They are also ligands for unregulated receptor-mediated uptake of oxLDL by monocyte macrophages leading to foam cell formation.