לוח שנה משולב

Weather and climate extremes such as cold spells, heat waves, heavy precipitation or windstorms have long been considered challenging to adequately predict a few days in advance. Even at shorter time scales, it is sometimes difficult to estimate the magnitude and impact area accurately. Therefore, they have been selected as one of the grand challenges by the World Climate Research Program. Several studies suggest that extreme temperatures or heavy precipitation events may become more frequent and more intense with climate change, making this topic even more pertinent.
The ability to predict the development of any dynamical system (a system that evolves in time), depends on: 1) its persistence, meaning that a persistent system will be easier to predict and 2) the number of options the system can develop into/from, meaning that systems with a small number of options will be easier to predict. Recent advances in dynamical systems theory allow to efficiently compute these metrics from model data. Our earlier findings show that the dynamical systems metrics can serve as an extremely informative qualitative method for evaluating the predictability and dynamics of synoptic systems over the Eastern Mediterranean.
The talk will discuss this novel dynamic approach and its recent applications in extreme weather forecasting, as well as in climate model projections over the Eastern Mediterranean.

During early life the neural code must develop to appropriately transform sensory inputs into behavioural outputs. However little is known about how developments in neural representations directly impact on behaviour. By combining behavioural analysis with 2-photon calcium imaging at multiple timepoints from 4 to 15 dpf in the optic tectum of developing zebrafish larvae, we demonstrate a link between the maturity of neural coding in the visual brain and developmental changes in visually-guided behavior. We show that visually-driven hunting behavior improves from 4 to 15 days post-fertilization, becoming faster and more accurate. During the same period population activity in parts of the optic tectum refines, improving decoding and information transmission for particular spatial positions. Together these results show that developmental signatures of an emerging neural code can be directly related to observable properties of behaviour.

Please click the link below to join:
https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09

Meeting ID: 966 0803 3618
Password: 564068


Host: Dr. Rita Schmidt

rita.schmidt@weizmann.ac.il tel: 9070

Zoom link to join
https://weizmann.zoom.us/j/7576151783?pwd=V2hoQUxvN1IzVlRCU3ZESmcwMHA2Zz09


Meeting ID 7576151783
Password – 050925

Although animals are known to heavily rely on chemical signals for intraspecies communication, the matter of human chemical communication remains greatly contentious. I will present evidence supporting the claim that humans, just like other animals, rely on bodily-odors to effectively navigate the social world. First, I will present a quantification of people’s overt olfactory-sampling behavior. Of approximately 400 respondents, 94% acknowledged engaging in smelling their close relationships, and approximately 60% acknowledged sniffing strangers. Next, we tested if this olfactory information is employed for socially-relevant behavioral decisions, such as trust, a key element in human socialization. We found that subliminal exposure to body-odor increased implicit trustworthiness attributed to anthropomorphic non-humans. Finally, I will describe the effect of a specific body-volatile, Hexadecanal (HEX), on human impulsive aggression. Using validated behavioral paradigms, we observed a remarkable dissociation: sniffing HEX blocked aggression in men, but triggered aggression in women. Using functional brain imaging, we uncovered a pattern of brain activity mirroring behavior: In both men and women, HEX increased activity in an area implicated in the perception of social cues. Hex then modulated functional connectivity in a brain network implicated in aggressive behavior in a sex-dependent manner.
Altogether, the thesis puts forward the hypothesis that chemosignals are a form of human social communication. Under this premise, human sampling behavior of self and others’ body-volatiles provides one with important information that, in turn, affects behaviors central to human society, such as trust and aggression.

Zoom link to join:
https://weizmann.zoom.us/j/98031517872?pwd=U0EvNG5EdGJBL24zWmpKUlY1akdnZz09

Meeting ID: 980 3151 7872
Password: 976632

The Hadley circulation is a key element of the climate system. It is traditionally defined as the zonally averaged meridional circulation in the tropics, therefore treated as a zonally symmetric phenomenon. However, differences in temperature between land and sea cause zonal asymmetries on Earth, dramatically affecting the circulation. This longitudinal dependence of the meridional circulation evokes questions about where and when the actual large scale tropical circulation occurs. Here, we look into the connection between the longitudinally dependent meridional circulation, and the actual large scale transport of air in the tropics using a coupled Eulerian and Lagrangian approach. Decomposing the velocity field into rotational and divergent components, we identify how each component affects the actual circulation. We propose an alternative definition for the circulation, that describes the actual path of air parcels in the tropics, as a tropical atmospheric conveyor belt. We further investigate this definition, analyzing the circulation under climate change and its effect on precipitation changes. We show that in order to predict future climate, the regionality and three-dimensionality of the large-scale tropical circulation must be taken into account. We find that the changes in the circulation vary significantly over longitude, and are overlooked when analyzing the zonally averaged meridional circulation. The circulation is strengthening and expanding in the center of the Pacific, a region where the circulation barely existed in past. On the other hand, the circulation is weakening in the Indo-Pacific region, where it was the most significant in the past. These differences appear as a shift in the region of ascent of the conveyor belt, that is revealed when analyzing the decomposed vertical wind. The pattern of weakening of the ascent in the Indo-Pacific and strengthening in the center of the Pacific explains the projected changes in precipitation. The Indo-Pacific region is drying, while the precipitation in the center of the Pacific is intensifying.

I will discuss two studies from my laboratory, that reveal differential role of hypothalamic paraventricular and supraoptic oxytocin neurons, as well as anterior hypothalamic neurons in social decision making of adult male mice.
Zoom link to join:
https://weizmann.zoom.us/j/96608033618?pwd=SEdJUkR2ZzRBZ3laUUdGbWR1VFJTdz09

Meeting ID: 966 0803 3618
Password: 564068


Host: Dr. Rita Schmidt rita.schmidt@weizmann.ac.il tel: 9070

Abstract: The present seminar will review our work in 1H LF NMR energy relaxation time technology and its application in chemical and morphological characterization and monitoring of oxidation of polyunsaturated fatty acids (PUFA) found in many important commercial products such as edible oils, foods, and biological systems. PUFA’s aggregates are related simultaneously with material’s functionality and degradation. The multiple double bonds and allylic carbons characteristics of the PUFA’s molecular structure are responsible for its oxidation susceptibility and can result in the degrade of the product’s functionality and formation of toxic substances. Wherein individual PUFA molecules have specific structures their material functionality and stability against oxidation are strongly depended on their aggregate structures such as in oils or within aqueous emulsions and specific arrangements within these structures with other components such as antioxidants is an important material parameter.
The oxidation degree of PUFA’s rich materials can be measured via different methods such as volumetric, spectroscopic and chromatographic technologies. The traditional technologies based on titrimetric techniques have many drawbacks. These methods need strict time regimes during individual stages of analyzes, control of the intensity of the agitation and control of reaction components including light and atmospheric oxygen exposure. Other disadvantage of these traditional methodologies is the requirement of a large amount of solvents, being environmental unfriendly. In order to overcome the disadvantages of the traditional technologies used to monitor oxidation we are suggesting the use 1H LF NMR relaxation. This technology does not require organic solvents, complex samples preparation and the sample is preserved after analysis. The 1H LF NMR generates 2D T1 (spin-lattice) vs. T2 (spin-spin) energy relaxation time domain that is able together with self-diffusion test to characterize chemical and morphologically complex aggregate materials such as PUFA in liquid or solid assembly or in presence of interfacial forces of water. In addition, these spectra can efficiently monitor oxidation and assess antioxidants efficacy.
We demonstrate the work we have done to date on the 1H LF NMR data processing optimization and the application of this technology in the characterization and monitoring of oxidation on oils on fatty acids saturated, monounsaturated and polyunsaturated. This sensor application is of relevant contributions for diverse fields such as food industries, pharmaceuticals, cosmetics and biofuels.
The seminar is divided into three parts:
a) Optimization of the ILT data processing technology of 1H LF NMR energy relaxation time. This study showed the efficiency of the regularization parameters for data reconstruction, and a relative high accuracy of the primal dual convex objectives (PDCO) solutions in comparison to the graphic results of real data.
b) Developing of intelligent NMR relaxation sensor applications of fatty acids (FA) with saturated chains, MUFA and PUFA-rich oils for their chemical and physical/morphological characterization and monitoring of their autoxidation. Detailed fingerprinting chemical and morphological maps
were generated for saturated FAs, MUFAs, PUFAs and their oxidation polymerized final products. It was possible to propose peak assignments to the various spin-lattice (T1) and spin –spin (T2) energy relaxation time proton populations (TD) based on the molecular segmental motions of the different fatty acids chemical and structural segments (e.g., glycerol; double bonds; aliphatic chains; and tails) to generate an explicatory dictionary of T1 and T2 values with chemical and physical/morphological structures and their changes due to oxidation.
c) Developing of intelligent 1H LF NMR energy relaxation time domain sensor application for PUFA-rich oil-in-water emulsions characterization and monitoring autoxidation. Emulsions based on linseeds, very rich in α-linolenic acid PUFA (18:3) and structural oleosin protein and other emulsification agents naturally producing nano-scale oxidation stable oil bodies, were formed from linseed in water. The linseed emulsions enriched with PUFA-rich fish oil were analyzed under thermal oxidation conditions, using 1H LF NMR T1-T2 energy relaxation time reconstruction for determining the oil bodies composition and structure and oxidative stability.