181 research outputs found
Imagination is All You Need! Curved Contrastive Learning for Abstract Sequence Modeling Utilized on Long Short-Term Dialogue Planning
Inspired by the curvature of space-time (Einstein, 1921), we introduce Curved
Contrastive Learning (CCL), a novel representation learning technique for
learning the relative turn distance between utterance pairs in multi-turn
dialogues. The resulting bi-encoder models can guide transformers as a response
ranking model towards a goal in a zero-shot fashion by projecting the goal
utterance and the corresponding reply candidates into a latent space. Here the
cosine similarity indicates the distance/reachability of a candidate utterance
toward the corresponding goal. Furthermore, we explore how these
forward-entailing language representations can be utilized for assessing the
likelihood of sequences by the entailment strength i.e. through the cosine
similarity of its individual members (encoded separately) as an emergent
property in the curved space. These non-local properties allow us to imagine
the likelihood of future patterns in dialogues, specifically by
ordering/identifying future goal utterances that are multiple turns away, given
a dialogue context. As part of our analysis, we investigate characteristics
that make conversations (un)plannable and find strong evidence of planning
capability over multiple turns (in 61.56% over 3 turns) in conversations from
the DailyDialog (Li et al., 2017) dataset. Finally, we show how we achieve
higher efficiency in sequence modeling tasks compared to previous work thanks
to our relativistic approach, where only the last utterance needs to be encoded
and computed during inference.Comment: Accepted in ACL 2023 Finding
Untersuchungen und Messmethoden zur Reinfiltration in sandigen Aquiferen zum Einsatz der Düsensauginfiltrationstechnik
From Forest Soil to the Canopy: Increased Habitat Diversity Does Not Increase Species Richness of Cercozoa and Oomycota in Tree Canopies
Tree canopies provide habitats for diverse and until now, still poorly characterized communities of microbial eukaryotes. One of the most general patterns in community ecology is the increase in species richness with increasing habitat diversity. Thus, environmental heterogeneity of tree canopies should be an important factor governing community structure and diversity in this subsystem of forest ecosystems. Nevertheless, it is unknown if similar patterns are reflected at the microbial scale within unicellular eukaryotes (protists). In this study, high-throughput sequencing of two prominent protistan taxa, Cercozoa (Rhizaria) and Oomycota (Stramenopiles), was performed. Group specific primers were used to comprehensively analyze their diversity in various microhabitats of a floodplain forest from the forest floor to the canopy region. Beta diversity indicated highly dissimilar protistan communities in the investigated microhabitats. However, the majority of operational taxonomic units (OTUs) was present in all samples, and therefore differences in beta diversity were mainly related to species performance (i.e., relative abundance). Accordingly, habitat diversity strongly favored distinct protistan taxa in terms of abundance, but due to their almost ubiquitous distribution the effect of species richness on community composition was negligible
Unexplored Character Diversity in Onychophora (Velvet Worms): A Comparative Study of Three Peripatid Species
Low character variation among onychophoran species has been an obstacle for taxonomic and phylogenetic studies in the past, however we have identified a number of new and informative characters using morphological, molecular, and chromosomal techniques. Our analyses involved a detailed examination of Epiperipatus biolleyi from Costa Rica, Eoperipatus sp. from Thailand, and a new onychophoran species and genus from Costa Rica, Principapillatus hitoyensisgen. et sp. nov.. Scanning electron microscopy on embryos and specimens of varying age revealed novel morphological characters and character states, including the distribution of different receptor types along the antennae, the arrangement and form of papillae on the head, body and legs, the presence and shape of interpedal structures and fields of modified scales on the ventral body surface, the arrangement of lips around the mouth, the number, position and structure of crural tubercles and anal gland openings, and the presence and shape of embryonic foot projections. Karyotypic analyses revealed differences in the number and size of chromosomes among the species studied. The results of our phylogenetic analyses using mitochondrial COI and 12S rRNA gene sequences are in line with morphological and karyotype data. However, our data show a large number of unexplored, albeit informative, characters in the Peripatidae. We suggest that analysing these characters in additional species would help unravel species diversity and phylogeny in the Onychophora, and that inconsistencies among most diagnostic features used for the peripatid genera in the literature could be addressed by identifying a suite of characters common to all peripatids.This study was supported by a Ph.D. fellowship of the Conselho Nacional de Desenvolvimento Cientı´fico e Tecnolo´gico (CNPq: 290029/2010-4) and by a
SYNTHESYS grant (financed by the European Community Research Infrastructure Action - FP7 Integrating Activities Programme: http://www.synthesys.info/) to
ISO. GM is a Research Group Leader supported by the Emmy Noether Programme of the German Research Foundation (DFG: Ma 4147/3-1). The funders had no
role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
Multi-Parameter Fluorescence Detection at the Single-Molecule Level : Techniques and Applications
Fluorescence-based assays using single-molecule techniques are evolving into a very important tool in science. These techniques include not only direct detection and analysis of single-molecule events, but also spectroscopic analysis through fluctuation methods such as FCS (fluorescence correlation spectroscopy) or FIDA (fluorescence intensity distribution analysis). What are the advantages of these techniques and why is fluorescence chosen as the readout?
This article will give an overview of fluorescence techniques and applications of single-molecule detection and analysis. It is focused on the detection of fluorescence emitted from freely diffusing molecules in solution. A confocal microscope is described, which uses special electronics for detection and enables the observation of fluorescence emission from single molecules along with monitoring of various fluorescence parameters (MFD). In the first part, procedures such as the detection and identification of single molecules, the monitoring of rare events, the direct temporal observation of binding events and conformational dynamics, as well as the possibility of selective spectroscopy of molecular states are described. Industrial applications such as HTS are illustrated by a description of using fluctuation methods such as FCS and FIDA to resolve characteristic properties of biological assays, e.g., ligand-protein and -vesicle binding or enzymatic reactions
Dissecting the molecular organization of the translocon-associated protein complex
In eukaryotic cells, one-third of all proteins must be transported across or inserted into the endoplasmic reticulum (ER) membrane by the ER protein translocon. The translocon-associated protein (TRAP) complex is an integral component of the translocon, assisting the Sec61 protein-conducting channel by regulating signal sequence and transmembrane helix insertion in a substrate-dependent manner. Here we use cryo-electron tomography (CET) to study the structure of the native translocon in evolutionarily divergent organisms and disease-linked TRAP mutant fibroblasts from human patients. The structural differences detected by subtomogram analysis form a basis for dissecting the molecular organization of the TRAP complex. We assign positions to the four TRAP subunits within the complex, providing insights into their individual functions. The revealed molecular architecture of a central translocon component advances our understanding of membrane protein biogenesis and sheds light on the role of TRAP in human congenital disorders of glycosylation
Gradient of Rigidity in the Lamellipodia of Migrating Cells Revealed by Atomic Force Microscopy
Changes in mechanical properties of the cytoplasm have been implicated in cell motility, but there is little information about these properties in specific regions of the cell at specific stages of the cell migration process. Fish epidermal keratocytes with their stable shape and steady motion represent an ideal system to elucidate temporal and spatial dynamics of the mechanical state of the cytoplasm. As the shape of the cell does not change during motion and actin network in the lamellipodia is nearly stationary with respect to the substrate, the spatial changes in the direction from the front to the rear of the cell reflect temporal changes in the actin network after its assembly at the leading edge. We have utilized atomic force microscopy to determine the rigidity of fish keratocyte lamellipodia as a function of time/distance from the leading edge. Although vertical thickness remained nearly constant throughout the lamellipodia, the rigidity exhibited a gradual but significant decrease from the front to the rear of the lamellipodia. The rigidity pro. le resembled closely the actin density pro. le, suggesting that the dynamics of rigidity are due to actin depolymerization. The decrease of rigidity may play a role in facilitating the contraction of the actin-myosin network at the lamellipodium/cell body transition zone
Resensies
Book Review 1Book Title: Skollie: One man’s struggle to survive by telling storiesBook Author: John W. FredericksCape Town: Penguin Random House. 251 pp. ISBN: 978-1-77609-199-7.Book Review 2Book Title: A Gap in the HedgeBook Author: Johan Vlok LouwCape Town: Umuzi, 2017. 233 pp. ISBN: 978-1-4152-08915Book Review 3Book Title: Iziganeko zesizwe: Occasional Poems (1900–1943)Book Authors: S.E.K. Mqhayi. Eds. and trans. Jeff Opland and Peter T. MtuzePietermaritzburg: University of KwaZulu Natal Press, 2017. 469 pp. ISBN: 9781869143343; e-ISBN: 9781869143350.Book Review 4Book Title: Oorlog en terpentynBook Authors: Stefan Hertmans. Vertaal deur Daniel HugoPretoria: Protea Boekhuis, 2016. 335 pp. ISBN: 978-1-4853-0610-8; e-Boek: 978-1-4853-0722-8; Epub: 978-1-4853-0723-5.Book Review 5Book Title: Groen soos die hemel daarboBook Author: Eben VenterKaapstad: Tafelberg, 212 pp. ISBN: 978-0-624-08261-3.Book Review 6Book Title: Die wêreld van Charlie OengBook Author: Etienne van HeerdenKaapstad: Tafelberg, 2017. 559 pp. ISBN 978-0-624-08052-7.Book Review 7Book Title: Die diepblou seeBook Author: François LootsKaapstad: Umuzi, 2017. 239 pp. ISBN: 978-1-4152-0953-0.Book Review 8Book Title: Die derde spoelBook Author: S.J. NaudéKaapstad: Umuzi, 2017. 342 pp. ISBN: 978-1-4152-0747-5 (Druk). ISBN: 978-1-4152-0748-2 (ePub).Book Review 9Book Title: Nou, hierBook Author: Corné CoetzeeKaapstad: Human & Rousseau, 2017. 107 pp. ISBN 978-0-7981-7620-0.Book Review 10Book Title: RadbraakBook Author: Jolyn PhillipsKaapstad: Human & Rousseau, 2017. 68 pp. ISBN: 978-0-7981-7616-3.Book Review 11Book Title: VuurvasBook Author: Carel AntonissenNaledi, 2016. ISBN 978-0-928316-97-1.Book Review 12Book Title: Voor ek my kom kryBook Author: Pirow BekkerPretoria: Protea Boekhuis, 2017. 110 pp. ISBN: 978-1-4853-0648-1.Book Review 13Book Title: Nuwe stemme 6Book Authors: Bibi Slippers en Charl-Pierre Naudé (samenstellers)Kaapstad: Tafelberg, 2017. 176 pp. ISBN 9780624082644.Book Review 14Book Title: UittogboekBook Author: Johan MyburgPretoria: Protea, 2017. 100 pp. ISBN: 9781485307761.Book Review 15Book Title: Krap uit die seeBook Author: Fourie BothaPretoria: Protea Boekehuis, 2017. 64 pp. ISBN 9781485307570.Book Review 16Book Title: Skepelinge. Aanloop tot ‘n romanBook Author: Karel SchoemanKaapstad: Human & Rousseau, 2017. 576 pp. ISBN: 978079817610.Book Review 17Book Title: Die reis gaan inwaarts: Die kuns van sterwe in kreatiewe werke van Karel SchoemanBook Author: Cas WepenerStellenbosch: Sun MeDIA MeTRO. Druknaam: SUN PRESS, 2017. 233 pp. ISBN: 978-1-928355-14-4 (Druk); ISBN: 979-1-928355-15-1 (e-boek)
- …