Filters








1,317 Hits in 1.0 sec

A stratospheric connection to Atlantic climate variability

Thomas Reichler, Junsu Kim, Elisa Manzini, Jürgen Kröger
2012 Nature Geoscience  
The stratosphere is connected to tropospheric weather and climate. In particular, extreme stratospheric circulation events are known to exert a dynamical feedback on the troposphere 1 . However, it is unclear whether the state of the stratosphere also affects the ocean and its circulation. A co-variability of decadal stratospheric flow variations and conditions in the North Atlantic Ocean has been suggested, but such findings are based on short simulations with only one climate model 2 . Here
more » ... te model 2 . Here we assess ocean reanalysis data and find that, over the previous 30 years, the stratosphere and the Atlantic thermohaline circulation experienced low-frequency variations that were similar to each other. Using climate models, we demonstrate that this similarity is consistent with the hypothesis that variations in the sequence of stratospheric circulation anomalies, combined with the persistence of individual anomalies, significantly affect the North Atlantic Ocean. Our analyses identify a previously unknown source for decadal climate variability and suggest that simulations of deep layers of the atmosphere and the ocean are needed for realistic predictions of climate. The ocean has a large thermal inertia and is dominated by variability on timescales of years to decades. Traditionally, atmospheric influences on the ocean are understood from the stochastic climate model paradigm, in which the troposphere is thought to provide a white-noise forcing that is integrated by the ocean to yield a low-frequency response 3 . In this study we propose another relevant influence, which is related to the stratosphere. The stratosphere is characterized by persistent flow dynamics 4 and considerable multi-decadal energy 5-7 . Variations in the strength of the wintertime northern hemispheric stratospheric vortex, so called 'polar vortex events', are known to last for many weeks, as does their impact on the troposphere 8 . An example is stratospheric sudden warmings (SSWs), prolonged time periods with an unusually weak and warm polar vortex. SSWs occur on average every second year, but observations over the past 30 years reveal an intriguing quasi-decadal rhythm in the year-to-year occurrence of such events: during the 1990s, the Arctic winter stratosphere was characterized by an almost complete absence of SSWs, but during the 1980s and also during the 2000s the stratosphere experienced a record number of such events (Fig. 1a) . A connection between the stratosphere and the ocean can be established by the North Atlantic Oscillation (NAO), a largescale pattern of near-surface circulation anomalies over the North Atlantic. Polar vortex events modulate the NAO polarity, with a strong vortex leading to a positive and a weak vortex to a negative NAO (ref. 8). NAO variations in turn are linked to circulation variability in the North Atlantic. The NAO induces anomalous
doi:10.1038/ngeo1586 fatcat:q5lx46a2fjhfdppk7fg2s5qasm

Distinct interhemispheric connectivity at the level of the olfactory bulb emerges during Xenopus laevis metamorphosis [article]

Lukas Weiss, Paola Segoviano Arias, Thomas Offner, Sara Joy Hawkins, Thomas Hassenkloever, Ivan Manzini
2021 bioRxiv   pre-print
Acknowledgments We thank the members of the Manzini Lab for fruitful discussion.  ...  Putatively microvillous ORNs projecting to the lateral glomeruli have a cAMP-independent second messenger pathway (Manzini et al., 2002; Manzini and Schild, 2003) and are mostly responsive to amino acids  ...  This is well documented for all major groups of anurans: Archaeobatrachians (Benzekri and Reiss, 2012) , Mesobatrachians (Manzini and Schild, 2010) and Neobatrachians (Jermakowicz et al., 2004; Jungblut  ... 
doi:10.1101/2021.05.11.443461 fatcat:j4fnpxy2xbgyxjs5x2uyuwvmt4

Olfaction across the water–air interface in anuran amphibians

Lukas Weiss, Ivan Manzini, Thomas Hassenklöver
2021 Cell and Tissue Research  
et al. 2002; Manzini and Schild 2003; Gliem et al. 2013) .  ...  It remains to be shown if the functional odor map described in previous work by our group (Manzini et al. 2002; Manzini and Schild 2010; Gliem et al. 2013 ) is retained in glomeruli of the "water-bulb  ... 
doi:10.1007/s00441-020-03377-5 pmid:33496878 fatcat:yz7t7mthyfhyjatveuzkajp3qa

Dual processing of sulfated steroids in the olfactory system of an anuran amphibian

Alfredo Sansone, Thomas Hassenklöver, Thomas Offner, Xiaoyan Fu, Timothy E. Holy, Ivan Manzini
2015 Frontiers in Cellular Neuroscience  
Citation: Sansone A, Hassenklöver T, Offner T, Fu X, Holy TE and Manzini I (2015) Dual processing of sulfated steroids in the olfactory system of an anuran amphibian.  ...  Amino acids are well characterized odorants in Xenopus laevis (Manzini and Schild, 2004; Gliem et al., 2013; Sansone et al., 2014a) .  ...  For orientation during this procedure we previously electroporated neurons in the MOE and VNO with Alexa-594 dextran (for details see Manzini, 2013, 2014) .  ... 
doi:10.3389/fncel.2015.00373 pmid:26441543 pmcid:PMC4585043 fatcat:6x5ax3o7r5bhxa27ewhellzhny

Seq2Seq2Sentiment: Multimodal Sequence to Sequence Models for Sentiment Analysis [article]

Hai Pham, Thomas Manzini, Paul Pu Liang, Barnabas Poczos
2018 arXiv   pre-print
Multimodal machine learning is a core research area spanning the language, visual and acoustic modalities. The central challenge in multimodal learning involves learning representations that can process and relate information from multiple modalities. In this paper, we propose two methods for unsupervised learning of joint multimodal representations using sequence to sequence (Seq2Seq) methods: a Seq2Seq Modality Translation Model and a Hierarchical Seq2Seq Modality Translation Model. We also
more » ... on Model. We also explore multiple different variations on the multimodal inputs and outputs of these seq2seq models. Our experiments on multimodal sentiment analysis using the CMU-MOSI dataset indicate that our methods learn informative multimodal representations that outperform the baselines and achieve improved performance on multimodal sentiment analysis, specifically in the Bimodal case where our model is able to improve F1 Score by twelve points. We also discuss future directions for multimodal Seq2Seq methods.
arXiv:1807.03915v2 fatcat:6zzjqlxfdfa2zdsvhu35xvprle

Gly166in the NK1receptor regulates tachykinin selectivity and receptor conformation1

Alessandra Ciucci, Carla Palma, Daniela Riitano, Stefano Manzini, Thomas M Werge
1997 FEBS Letters  
We have studied the pharmacological properties of genetically engineered human NK, tachykinin receptors in which residues at the extracellular surface of the fourth transmembranal domain were substituted with the corresponding amino acids from the NK 2 receptor. We show that substitution of G166C:Y167F in the human ΝΚχ receptor induces high affinity binding of a group of tachykinin ligands, known as 'septides' (i.e. neurokinin A, neurokinin B, [pGlu e ,Pro 9 ]-substance ρ β η and substance
more » ... and substance P-methylester). In contrast, binding of substance P and non-peptide antagonists is unaffected by these mutations. This effect parallels that found on the rat receptor and is therefore species specific. Second, we demonstrate that mutation of Gly 166 to Cys alone is both necessary and sufficient to create this pan-reactive tachykinin receptor, whereas replacement of Tyr 167 by Phe has no detectable effect on the pharmacological properties of the receptor. Furthermore, analysis of the effect of ./V-ethylmaleimide and dithiothreitol on binding of radiolabelled substance P documents differences in the mode in which this ligand interacts with wild-type and mutant receptors and supports the existence of a mutational induced change in the conformational status of the ΝΚχ receptor.
doi:10.1016/s0014-5793(97)01236-2 pmid:9373180 fatcat:nogtea6cyjer5dukoi32rrgggm

Multi-glomerular projection of single olfactory receptor neurons is conserved among amphibians [article]

Lukas Weiss, Lucas D Jungblut, Andrea G Pozzi, Barbara S Zielinski, Lauren A O'Connell, Thomas Hassenkloever, Ivan Manzini
2019 bioRxiv   pre-print
Acknowledgements We thank all the present and past members of the Manzini laboratory for fruitful discussion and input, especially Thomas Offner and Sara Joy Hawkins.  ... 
doi:10.1101/788133 fatcat:xul6ohp7ofasbbr6bc36fnz32u

The Olfactory System as a Model to Study Axonal Growth Patterns and Morphology In Vivo

Thomas Hassenklöver, Ivan Manzini
2014 Journal of Visualized Experiments  
., Manzini, I. The Olfactory System as a Model to Study Axonal Growth Patterns and Morphology In Vivo.  ...  For more examples also see Hassenklöver and Manzini . Clogged or broken tips of micropipettes can also hinder successful electroporation.  ... 
doi:10.3791/52143 pmid:25406975 pmcid:PMC4353389 fatcat:cmeisjpdifgrvme5hn74pv3koi

Nucleotide-induced Ca2+signaling in sustentacular supporting cells of the olfactory epithelium

Thomas Hassenklöver, Silvia Kurtanska, Ilonka Bartoszek, Stephan Junek, Detlev Schild, Ivan Manzini
2008 Glia  
ORNs of Xenopus laevis tadpoles express multidrug resistance transporters (Manzini and Schild, 2003; Manzini et al., 2008) with a wide substrate spectrum, including Ca 21indicator dyes.  ... 
doi:10.1002/glia.20714 pmid:18551628 fatcat:bazho5fb65hyrez7wuksxo3tfy

Language Informed Modeling of Code-Switched Text

Khyathi Chandu, Thomas Manzini, Sumeet Singh, Alan W. Black
2018 Proceedings of the Third Workshop on Computational Approaches to Linguistic Code-Switching  
Code-switching (CS), the practice of alternating between two or more languages in conversations, is pervasive in most multilingual communities. CS texts have a complex interplay between languages and occur in informal contexts that make them harder to collect and construct NLP tools for. We approach this problem through Language Modeling (LM) on a new Hindi-English mixed corpus containing 59,189 unique sentences collected from blogging websites. We implement and discuss different Language
more » ... rent Language Models derived from a multi-layered LSTM architecture. We hypothesize that encoding language information strengthens a language model by helping to learn code-switching points. We show that our highest performing model achieves a test perplexity of 19.52 on the CS corpus that we collected and processed. On this data we demonstrate that our performance is an improvement over AWD-LSTM LM (a recent state of the art on monolingual English).
doi:10.18653/v1/w18-3211 dblp:conf/acl-codeswitch/ChanduMSB18 fatcat:xoplq7hxhvborndpkmjanj4gha

The quasi-biennial oscillation in a warmer climate: sensitivity to different gravity wave parameterizations

Sebastian Schirber, Elisa Manzini, Thomas Krismer, Marco Giorgetta
2014 Climate Dynamics  
The quasi-biennial oscillation (QBO) of equatorial zonal winds is a prominent feature of stratospheric dynamics. The QBO is driven downward-against the general tropical upwelling-by waves which emanate from the troposphere and travel upwards into the stratosphere. At the alternating shear zones of the QBO, the waves break, deposit momentum and cause a downward propagation of the wind maxima. The waves driving the QBO range from large scale Kelvin and Rossby-gravity waves to smaller scale
more » ... maller scale gravity waves (GW) with shorter horizontal wavelength. Dunkerton (1997) show that the contribution of intermediate inertia-GWs and mesoscale GWs is necessary to produce a QBO with realistic period and amplitude. For a more detailed description on the forcing and the physical mechanisms of the QBO (see the review paper by Baldwin et al. 2001) . Apart from being a phenomena to study wave-mean flow interactions in a fluid on a rotating sphere, the QBO influences other parts of the atmosphere, in both the stratosphere and the troposphere. Holton and Tan (1980) show that the easterly phase of the QBO is associated with weakening of the northern wintertime stratospheric polar vortex. In the troposphere, the QBO influences tropical cyclone tracks (Ho et al. 2009 ), the boreal summer monsoon (Giorgetta et al. 1999 ) and tropical deep convection (Collimore et al. 2003; Liess and Geller 2012) . Recent work shows that the QBO reveals predictability in the tropics (Pohlmann et al. 2013) and weak predictability in the north Atlantic sector (Scaife et al. 2014) . Potential changes of the QBO in a warmer climate will therefore influence tropospheric processes. Abstract In order to simulate the quasi-biennial oscillation (QBO) with a realistic period and amplitude, general circulation models commonly include parameterizations of small scale gravity waves (GW). In this work, we explore how different GW parameterization setups determine the response of QBO properties to a warmer climate. Atmosphere-only experiments in both present day and warmer climate serve as testbed to analyze the effect of four different GW parameterization setups, active in the tropics. Having tuned the GW parameterizations to produce a realistic QBO in present day climate, we analyze changes of QBO properties in the warmer climate. The QBO period decreases in two parameterization setups by ~30 %, while the QBO period remains unchanged in the remaining two parameterization setups. In all parameterization setups, the QBO amplitude in the warmer climate weakens below 10 hPa but shows different behaviour above 10 hPa. We show that changes in QBO amplitude and changes in QBO period are inconsistent among experiments. In the chosen experimental design, the inconsistent future change in QBO properties among the suite of experiments depends solely on the choice of the GW parameterization setup.
doi:10.1007/s00382-014-2314-2 fatcat:gbogdcobdfaitb5o4ws562v3iq

Conservation of Glomerular Organization in the Main Olfactory Bulb of Anuran Larvae

Lukas Weiss, Lucas D. Jungblut, Andrea G. Pozzi, Lauren A. O'Connell, Thomas Hassenklöver, Ivan Manzini
2020 Frontiers in Neuroanatomy  
ACKNOWLEDGMENTS We thank all members of the Manzini laboratory for discussion, Anja Schnecko for technical assistance and Eva Fischer for support to set up experiments.  ...  A detailed account of glomerular organization in anurans is available only from the fully aquatic Xenopus laevis (Manzini and Schild, 2010) .  ...  These streams rely on different ORN types, second messenger cascades, and odorant receptor types (Manzini et al., 2002; Gliem et al., 2013) .  ... 
doi:10.3389/fnana.2020.00044 pmid:32792916 pmcid:PMC7393516 fatcat:2fzha6ngjjar3ctujgy726dvse

Amino Acid- vs. Peptide-Odorants: Responses of Individual Olfactory Receptor Neurons in an Aquatic Species

Thomas Hassenklöver, Lars P. Pallesen, Detlev Schild, Ivan Manzini, Johannes Reisert
2012 PLoS ONE  
Citation: Hassenklö ver T, Pallesen LP, Schild D, Manzini I (2012) Amino Acid-vs. Peptide-Odorants: Responses of Individual Olfactory Receptor Neurons in an Aquatic Species. PLoS ONE 7(12): e53097.  ... 
doi:10.1371/journal.pone.0053097 pmid:23300867 pmcid:PMC3531423 fatcat:ctd3q7wydnb4vp7c7wgfovjvgu

Found in Translation: Learning Robust Joint Representations by Cyclic Translations Between Modalities [article]

Hai Pham, Paul Pu Liang, Thomas Manzini, Louis-Philippe Morency, Barnabas Poczos
2020 arXiv   pre-print
Multimodal sentiment analysis is a core research area that studies speaker sentiment expressed from the language, visual, and acoustic modalities. The central challenge in multimodal learning involves inferring joint representations that can process and relate information from these modalities. However, existing work learns joint representations by requiring all modalities as input and as a result, the learned representations may be sensitive to noisy or missing modalities at test time. With
more » ... test time. With the recent success of sequence to sequence (Seq2Seq) models in machine translation, there is an opportunity to explore new ways of learning joint representations that may not require all input modalities at test time. In this paper, we propose a method to learn robust joint representations by translating between modalities. Our method is based on the key insight that translation from a source to a target modality provides a method of learning joint representations using only the source modality as input. We augment modality translations with a cycle consistency loss to ensure that our joint representations retain maximal information from all modalities. Once our translation model is trained with paired multimodal data, we only need data from the source modality at test time for final sentiment prediction. This ensures that our model remains robust from perturbations or missing information in the other modalities. We train our model with a coupled translation-prediction objective and it achieves new state-of-the-art results on multimodal sentiment analysis datasets: CMU-MOSI, ICT-MMMO, and YouTube. Additional experiments show that our model learns increasingly discriminative joint representations with more input modalities while maintaining robustness to missing or perturbed modalities.
arXiv:1812.07809v2 fatcat:fvxwz2xhsnfp7ny6shbzola6gm

Functional Reintegration of Sensory Neurons and Transitional Dendritic Reduction of Mitral/Tufted Cells during Injury-Induced Recovery of the Larval Xenopus Olfactory Circuit

Sara J. Hawkins, Lukas Weiss, Thomas Offner, Katarina Dittrich, Thomas Hassenklöver, Ivan Manzini
2017 Frontiers in Cellular Neuroscience  
Image stacks of the whole intact OB were acquired from the ventral side (for details see Hassenklöver and Manzini, 2014) using an upright multi-photon microscope (A1R-MP, Nikon).  ...  ., 2003; Manzini, 2015; Kosaka and Kosaka, 2016) . A correct integration is essential to allow the successful propagation of olfactory information from second order neurons to higher brain centers.  ...  Copyright © 2017 Hawkins, Weiss, Offner, Dittrich, Hassenklöver and Manzini. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY).  ... 
doi:10.3389/fncel.2017.00380 pmid:29234276 pmcid:PMC5712363 fatcat:imogawrgdvhobfdgk6idqrees4
« Previous Showing results 1 — 15 out of 1,317 results