Within the lichen family Teloschistaceae, a high number of genera are restricted to the extreme southern part of the Southern Hemisphere. The taxonomy and phylogeny of the southern genus Gondwania ...have been analyzed based upon fieldwork in Antarctica, Patagonia, New Zealand and Tasmania and subsequent studies including molecular methods. Five species are accepted in the genus Gondwanea including G. inclinans and G. joannae that are combined into the genus. Two species are included in the neighboring new genus Transdrakea, T. alacalufes, a saxicolous species from Patagonia, which is described as new to science and T. schofieldii. Based on molecular data, Austroplaca imperialis is described as a new species to accommodate Patagonian specimens previously named G. regalis. Even though morphologically very similar, the two species are distinct based on molecular and chemical characters and distribution. Gondwania and Transdrakea are chemically homogenous with parietin as the very dominant compound; Transdrakea has a very reduced thallus, whereas Gondwania includes species with crustose thalli, as well as species with fruticulose growth habits. G. inclinans and G. cribrosa are only known from Australia/New Zealand. G. regalis, G. joannae and T. schofieldii are only known from Antarctica. G. sublobulata is confirmed from Patagonia and the Falkland Islands, but Antarctic specimens previously named G. sublobulata belong to G. joannae. G. sejongensis is shown to be a synonym to G. joannae. A key to Gondwania and Transdrakea species is presented.
Lichens represent a symbiotic relationship between at least one fungal and one photosynthetic partner. The association between the lichen-forming fungus Mastodia tessellata (Verrucariaceae) and ...different species of Prasiola (Trebouxiophyceae) has an amphipolar distribution and represents a unique case study for the understanding of lichen symbiosis because of the macroalgal nature of the photobiont, the flexibility of the symbiotic interaction and the co-existence of free-living and lichenized forms in the same microenvironment. In this context, we aimed to (1) characterize the photosynthetic performance of co-occurring populations of free-living and lichenized Prasiola and (2) assess the effect of the symbiosis on water relations in Prasiola, including its tolerance of desiccation and its survival and performance under sub-zero temperatures.
Photochemical responses to irradiance, desiccation and freezing temperature and pressure-volume curves of co-existing free-living and lichenized Prasiola thalli were measured in situ in Livingston Island (Maritime Antarctica). Analyses of photosynthetic pigment, glass transition and ice nucleation temperatures, surface hydrophobicity extent and molecular analyses were conducted in the laboratory.
Free-living and lichenized forms of Prasiola were identified as two different species: P. crispa and Prasiola sp., respectively. While lichenization appears to have no effect on the photochemical performance of the alga or its tolerance of desiccation (in the short term), the symbiotic lifestyle involves (1) changes in water relations, (2) a considerable decrease in the net carbon balance and (3) enhanced freezing tolerance.
Our results support improved tolerance of sub-zero temperature as the main benefit of lichenization for the photobiont, but highlight that lichenization represents a delicate equilibrium between a mutualistic and a less reciprocal relationship. In a warmer climate scenario, the spread of the free-living Prasiola to the detriment of the lichen form would be likely, with unknown consequences for Maritime Antarctic ecosystems.
As in other research fields, the development of learning analytics is influenced by the networks of researchers that contribute to it. This paper describes one of such networks: the Spanish Network ...of Learning Analytics (SNOLA). The paper presents the research lines of the members of SNOLA, as well as the main challenges that learning analytics has to address in the next few years as perceived by these researchers. This analysis is based on SNOLA's archival data and on a survey carried out to the current members of the network. Although this approach does not cover all the activity related to learning analytics in Spain, the results provide a representative overview of the current state of research related to learning analytics in this context. The paper describes these trends and the main challenges, among which we can point out the need to adopt an ethical commitment with data, to develop systems that respond to the requirements of the end users, and to reach a wider institutional impact.
Patient-derived organoids (PDOs) recapitulate tumor architecture, contain cancer stem cells and have predictive value supporting personalized medicine. Here we describe a large-scale functional ...screen of dual-targeting bispecific antibodies (bAbs) on a heterogeneous colorectal cancer PDO biobank and paired healthy colonic mucosa samples. More than 500 therapeutic bAbs generated against Wingless-related integration site (WNT) and receptor tyrosine kinase (RTK) targets were functionally evaluated by high-content imaging to capture the complexity of PDO responses. Our drug discovery strategy resulted in the generation of MCLA-158, a bAb that specifically triggers epidermal growth factor receptor degradation in leucine-rich repeat-containing G-protein-coupled receptor 5-positive (LGR5+) cancer stem cells but shows minimal toxicity toward healthy LGR5+ colon stem cells. MCLA-158 exhibits therapeutic properties such as growth inhibition of KRAS-mutant colorectal cancers, blockade of metastasis initiation and suppression of tumor outgrowth in preclinical models for several epithelial cancer types.
This paper presents a novel genetic algorithm to solve the industrial Ethernet network partition problem (IENPP). A new switch-device encoding is presented for the problem, and incorporated into the ...genetic algorithm. This encoding has several advantages against the traditional representation used in previous approaches, which will be detailed in the paper. Also, several new genetic operators included in the genetic algorithm are described in the paper. Simulations in different network partition instances have shown the good performance of our approach: it obtains better results than a previous genetic algorithm due to the incorporation of the new representation and novel operators. Also the computational time of the proposed algorithm is better than that of the existing genetic algorithm for this problem.
Tal y como ocurre en otros campos de investigación, el desarrollo de la analítica del aprendizaje está influido por las redes de investigadores que contribuyen al mismo. Este artículo describe una de ...estas redes: la Red Española de Analítica de Aprendizaje (SNOLA). El artículo presenta las líneas de investigación de los miembros de SNOLA, así como los principales retos que la analítica del aprendizaje tiene que afrontar en los próximos años desde la visión de estos investigadores. Este análisis está basado en datos de archivo de SNOLA y en una encuesta realizada a los actuales miembros de la red. Aunque esta aproximación no cubre toda la actividad relacionada con analítica del aprendizaje en España, los resultados proporcionan una visión general representativa del estado de la investigación relacionada con analítica del aprendizaje en dicho contexto. El artículo muestra cuáles son estas tendencias y los principales retos, entre los que se encuentran la necesidad de adoptar un compromiso ético con los datos, desarrollar sistemas que respondan a las necesidades de los usuarios y alcanzar mayor impacto institucional.
Color reduction in images is an important problem in image processing, since it is a pre-processing step in applications such as image segmentation or compression. Different methods have been ...proposed in the literature, several of them involving nature-inspired algorithms such as neural networks. However, not many works involving evolutionary computation techniques have been applied to this problem. This paper proposes a novel evolutionary algorithm to tackle the color reduction of RGB images. The proposed evolutionary algorithm incorporates a procedure called incremental-encoding, consisting in starting the image quantization with a small number of colors, and including additional colors in a gradual form, until reaching the final number of quantization colors. In the experiments carried out we show that the incremental-encoding evolutionary algorithm improves the performance of the standard evolutionary algorithm in this problem. Also we show that it obtains better results than several existing color reduction techniques for color quantization problems.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
9.
Contributor contact details Ostroverkhova, O.; Shirota, Y.; Kageyama, H. ...
Handbook of organic materials for optical and (opto)electronic devices,
2013
Book Chapter
PDF
