An atmospheric origin of the multi-decadal bipolar seesaw

A prominent feature of recent climatic change is the strong Arctic surface warming that is contemporaneous with broad cooling over much of Antarctica and the Southern Ocean. Longer global surface temperature observations suggest that this contrasting pole-to-pole change could be a manifestation of a multi-decadal interhemispheric or bipolar seesaw pattern, which is well correlated with the North Atlantic sea surface temperature variability, and thus generally hypothesized to originate from Atlantic meridional overturning circulation oscillations. Here, we show that there is an atmospheric origin for this seesaw pattern. The results indicate that the Southern Ocean surface cooling (warming) associated with the seesaw pattern is attributable to the strengthening (weakening) of the Southern Hemisphere westerlies, which can be traced to Northern Hemisphere and tropical tropospheric warming (cooling). Antarctic ozone depletion has been suggested to be an important driving force behind the recently observed increase in the Southern Hemisphere's summer westerly winds; our results imply that Northern Hemisphere and tropical warming may have played a triggering role at an stage earlier than the first detectable Antarctic ozone depletion, and enhanced Antarctic ozone depletion through decreasing the lower stratospheric temperature

Certified PEFTSmoothing: Parameter-Efficient Fine-Tuning with Randomized Smoothing

Randomized smoothing is the primary certified robustness method for accessing the robustness of deep learning models to adversarial perturbations in the l2-norm, by adding isotropic Gaussian noise to the input image and returning the majority votes over the base classifier. Theoretically, it provides a certified norm bound, ensuring predictions of adversarial examples are stable within this bound. A notable constraint limiting widespread adoption is the necessity to retrain base models entirely from scratch to attain a robust version. This is because the base model fails to learn the noise-augmented data distribution to give an accurate vote. One intuitive way to overcome this challenge is to involve a custom-trained denoiser to eliminate the noise. However, this approach is inefficient and sub-optimal. Inspired by recent large model training procedures, we explore an alternative way named PEFTSmoothing to adapt the base model to learn the Gaussian noise-augmented data with Parameter-Efficient Fine-Tuning (PEFT) methods in both white-box and black-box settings. Extensive results demonstrate the effectiveness and efficiency of PEFTSmoothing, which allow us to certify over 98% accuracy for ViT on CIFAR-10, 20% higher than SoTA denoised smoothing, and over 61% accuracy on ImageNet which is 30% higher than CNN-based denoiser and comparable to the Diffusion-based denoiser

Effect of n-3 polyunsaturated fatty acids on dopaminergic neurons in substantia nigra, brain inflammatory response and behavior in mice with Parkinson’s disease

Purpose: To examine the effect of n-3 polyunsaturated fatty acids (PUFAs) on dopaminergic neurons in substantia nigra, intracerebral inflammatory response and ethology in mice with Parkinson’s disease (PD). Methods: Four groups of male C57BL/6 mice (n = 48) were used: normal control, negative control, n3PUFA, and Madopa groups. Except for normal control group, all groups were given 6- hydroxydopamine hydrochloride (6-OHDA) to establish Parkinson’s mice model. The expressions of tyrosine hydroxylase (TH) and calcium-binding protein (CB) in substantia nigra dopaminergic neurons were determined with immunohistochemistry and Western blot. The contents of nitric oxide (NO), tumor necrosis factor (TNF-α) and interferon γ (IFN-γ) (indices of intracerebral inflammatory response) were measured. Tremor paralysis, moving grid number, standing times, swimming ability, and the number of rollers in each group were observed as indices of ethology. Results: The number of TH and CB-positive neurons in the substantia nigra of n-3PUFA-treated mice was significantly increased, relative to those in Madopa-treated mice (p < 0.05). The expressions of TH and CB proteins in substantia nigra in n-3PUFA group were markedly higher than the corresponding expressions in Madopa-treated mice (p < 0.05). Decreased levels of NO, TNF-α and IFN-γ levels were seen in 3PUFA group, when compared to mice in Madopa group, but higher behavioral scores were obtained in n-3PUFA-treated mice, relative to Madopa-treated mice (p < 0.05). Conclusion: The n-3PUFAs protect substantia nigra compact dopaminergic neurons against Parkinson’s disease, alleviate immune inflammation, and improve the coordination of limb movement. Thus, n-3PUFAs have potential therapeutic application in the management of Parkinson’s disease

The Central Domain of MCPH1 Controls Development of the Cerebral Cortex and Gonads in Mice

MCPH1 is the first gene identified to be responsible for the human autosomal recessive disorder primary microcephaly (MCPH). Mutations in the N-terminal and central domains of MCPH1 are strongly associated with microcephaly in human patients. A recent study showed that the central domain of MCPH1, which is mainly encoded by exon 8, interacts with E3 ligase βTrCP2 and regulates the G2/M transition of the cell cycle. In order to investigate the biological functions of MCPH1’s central domain, we constructed a mouse model that lacked the central domain of MCPH1 by deleting its exon 8 (designated as Mcph1 -Δe8). Mcph1 -Δe8 mice exhibited a reduced brain size and thinner cortex, likely caused by a compromised self-renewal capacity and premature differentiation of Mcph1 -Δe8 neuroprogenitors during corticogenesis. Furthermore, Mcph1 -Δe8 mice were sterile because of a loss of germ cells in the testis and ovary. The embryonic fibroblasts of Mcph1 -Δe8 mice exhibited premature chromosome condensation (PCC). All of these findings indicate that Mcph1 -Δe8 mice are reminiscent of MCPH1 complete knockout mice and Mcph1 -ΔBR1 mice. Our study demonstrates that the central domain of MCPH1 represses microcephaly, and is essential for gonad development in mammals

Negative differential conductance effect and electrical anisotropy of 2D ZrB2 monolayers

Two-dimensional (2D) metal-diboride ZrB2 monolayers was predicted theoretically as a stable new electronic material [A. Lopez-Bezanilla, Phys. Rev. Mater., 2018, 2, 011002 (R)]. Here, we investigate its electronic transport properties along the zigzag (z-ZrB2) and armchair (a-ZrB2) directions, using the density functional theory and non-equilibrium Green's function methods. Under low biases, the 2D ZrB2 shows a similar electrical transport along zigzag and armchair directions as electric current propagates mostly via the metallic Zr-Zr bonds. However, it shows an electrical anistropy under high biases, and its I-V curves along zigzag and armchair directions diverge as the bias voltage is higher than 1.4 V, as more directional B-B transmission channels are opened. Importantly, both z-ZrB2 and a-ZrB2 show a pronounced negative differential conductance (NDC) effect and hence they can be promising for the use in NDC-based nanodevices