2,408 research outputs found
Veldkamp-Space Aspects of a Sequence of Nested Binary Segre Varieties
Let be a Segre variety that is -fold direct product of projective
lines of size three. Given two geometric hyperplanes and of
, let us call the triple the
Veldkamp line of . We shall demonstrate, for the sequence , that the properties of geometric hyperplanes of are fully
encoded in the properties of Veldkamp {\it lines} of . Using this
property, a complete classification of all types of geometric hyperplanes of
is provided. Employing the fact that, for , the
(ordinary part of) Veldkamp space of is , we shall
further describe which types of geometric hyperplanes of lie on a
certain hyperbolic quadric that
contains the and is invariant under its stabilizer group; in the
case we shall also single out those of them that correspond, via the
Lagrangian Grassmannian of type , to the set of 2295 maximal subspaces
of the symplectic polar space .Comment: 16 pages, 8 figures and 7 table
Protein glycosylation as a diagnostic and prognostic marker of chronic inflammatory gastrointestinal and liver diseases
Glycans are sequences of carbohydrates that are added to proteins or lipids to modulate their structure and function. Glycans modify proteins required for regulation of immune cells, and alterations have been associated with inflammatory conditions. For example, specific glycans regulate T-cell activation, structures, and functions of immunoglobulins; interactions between microbes and immune and epithelial cells; and malignant transformation in the intestine and liver. We review the effects of protein glycosylation in regulation of gastrointestinal and liver functions, and how alterations in glycosylation serve as diagnostic or prognostic factors, or as targets for therapy
On the Role of the Head Ganglia in Posture and Walking in Insects
In insects, locomotion is the result of rhythm generating thoracic circuits and their modulation by sensory reflexes and by inputs from the two head ganglia, the cerebral and the gnathal ganglia (GNG), which act as higher order neuronal centers playing different functions in the initiation, goal-direction, and maintenance of movement. Current knowledge on the various roles of major neuropiles of the cerebral ganglia (CRG), such as mushroom bodies (MB) and the central complex (CX), in particular, are discussed as well as the role of the GNG. Thoracic and head ganglia circuitries are connected by ascending and descending neurons. While less is known about the ascending neurons, recent studies in large insects and Drosophila have begun to unravel the identity of descending neurons and their appropriate roles in posture and locomotion. Descending inputs from the head ganglia are most important in initiating and modulating thoracic central pattern generating circuitries to achieve goal directed locomotion. In addition, the review will also deal with some known monoaminergic descending neurons which affect the motor circuits involved in posture and locomotion. In conclusion, we will present a few issues that have, until today, been little explored. For example, how and which descending neurons are selected to engage a specific motor behavior and how feedback from thoracic circuitry modulate the head ganglia circuitries. The review will discuss results from large insects, mainly locusts, crickets, and stick insects but will mostly focus on cockroaches and the fruit fly, Drosophila
Changes in tropical forest cover of Southeast Asia from 1990 to 2010
The study assesses the extent and trends of forest cover in Southeast Asia for the period 1990-2000-2010 and provides an overview on the main drivers of forest cover change. A systematic sample of 418 sites (10 km x 10 km size) located at the one-degree geographical confluence points and covered with satellite imagery at 30 m resolution is used for the assessment. For the analysis of satellite imagery techniques of image segmentation and automated classification were combined with visual interpretation and quality control, involving experts from Southeast Asian countries. Two forest cover classes, namely ‘Tree Cover’ and ‘Tree Cover Mosaic’, and three non-forest land cover classes were mapped. Area measures were derived for the individual sample sites and aggregated to regional statistical estimates, accounting for differences in sampling intensity due to geographical latitude, and extrapolating to uniform reference dates. For estimating the accuracy of our results an independent consistency assessment was performed from a subsample of 1572 mapping units, resulting in an overall agreement of > 85% for the general differentiation of forest cover versus non-forest cover. Forest cover in Southeast Asia is estimated at 268 Mha in 1990, dropping to 236 Mha in 2010, with annual change rates of 1.75 Mha (~0.67%) and 1.45 Mha (~0.59%) for the periods 1990-2000 and 2000-2010, respectively. The vast majority of forest cover loss (~ 2/3 for 2000-2010) occurred in insular Southeast Asia. Analysing the change patterns visible from satellite imagery and combining with the output of an expert consultation on drivers of forest change, the conversion of forest cover to cash crop plantations is ranked as the dominant driver of forest change in Southeast Asia, followed by selective logging and the establishment of tree plantations.JRC.H.3-Forest Resources and Climat
Health-related quality of life after radical prostatectomy and low-dose-rate brachytherapy for localized prostate cancer
To evaluate quality of life (QOL) after radical retropubic prostatectomy (RP) and low-dose-rate brachytherapy (BT)
Consumer preferences for front-of-pack calories labelling
Objective In light of the emerging obesity pandemic, front-of-pack calories labels may be an important tool to assist consumers in making informed healthier food choices. However, there is little prior research to guide key decisions on whether caloric content should be expressed in absolute terms or relative to recommended daily intake, whether it should be expressed in per serving or per 100 g and whether the information should be further brought alive for consumers in terms of what the extra calorie intake implies in relation to activity levels. The present study aimed at providing more insight into consumers¿ appreciation of front-of-pack labelling of caloric content of food products and their specific preferences for alternative execution formats for such information in Europe. Design For this purpose, eight executions of front-of-pack calorie flags were designed and their appeal and information value were extensively discussed with consumers through qualitative research in four different countries (Germany, The Netherlands, France and the UK). Results The results show that calories are well-understood and that participants were generally positive about front-of-pack flags, particularly when flags are uniform across products. The most liked flags are the simpler flags depicting only the number of calories per serving or per 100 g, while more complex flags including references to daily needs or exercise and the flag including a phrase referring to balanced lifestyle were least preferred. Some relevant differences between countries were observed. Although participants seem to be familiar with the notion of calories, they do not seem to fully understand how to apply them. Conclusion From the results, managerial implications for the design and implementation of front-of-pack calorie labelling as well as important directions for future research are discussed
An unexpected gene cluster for downstream degradation of alkylphenols in Sphingomonas sp. strain TTNP3
In silico analysis of nucleotide sequences flanking the recently found hydroquinone dioxygenase in Sphingomonas sp. strain TTNP3 revealed a gene cluster that encodes a hydroquinone catabolic pathway. In addition to the two open-reading frames encoding the recently characterized hydroquinone dioxygenase, the cluster consisted of six open-reading frames. We were able to express the three open-reading frames, hqdC, hqdD, and hqdE, and demonstrated that the three gene products, HqdC, HqdD, and HqdE had 4-hydroxymuconic semialdehyde dehydrogenase, maleylacetate reductase, and intradiol dioxygenase activity, respectively. Surprisingly, the gene cluster showed similarities to functionally related clusters found in members of the β- and γ-proteobacteria rather than to those found in other members of the genus Sphingomonas sensu lat
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