3,699 research outputs found
Fractionating spatial memory with glutamate receptor subunit-knockout mice.
No full textIn recent years, the contribution that different glutamate receptor subtypes and subunits make to spatial learning and memory has been studied extensively using genetically modified mice in which key proteins are knocked out. This has revealed dissociations between different aspects of spatial memory that were not previously apparent from lesion studies. For example, studies with GluA1 AMPAR [AMPA (alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid) receptor] subunit-knockout mice have revealed the presence of a GluA1-dependent, non-associative short-term memory mechanism that is important for performance on spatial working memory tasks, and a GluA1-independent, long-term associative memory mechanism which underlies performance on spatial reference memory tasks. Within this framework we have also studied the contributions of different GluN2-containing NMDARs [NMDA (N-methyl-D-aspartate) receptors] to spatial memory. Studies with GluN2 NMDAR mutants have revealed different contributions from GluN2A- and GluN2B-containing NMDARs to spatial learning. Furthermore, comparison of forebrain- and hippocampus-specific GluN2B-knockout mice has demonstrated that both hippocampal and extra-hippocampal NMDARs make important contributions to spatial memory performance
Neuroscience. Remembering the subtle differences.
No full textMice use a specific neurotransmitter receptor in the dentate gyrus of the hippocampus to detect small changes in their surroundings and differentiate between similar experiences
Entanglement and quantity in quantum space - About quantum measurement (II)
No full textAs a continuation and extension of "quantity in phase space" "quantity in quantum space" is introduced. With that, the disappearing of quantum interference discussed in a previous paper [S. Durr, et al., Nature 395 (1998) 33] is explained in the same spirit as our recent papers [Ren De-Ming, Commun. Theor. Phys. (Beijing, China) 41 (2004) 685, 833].Physics, MultidisciplinarySCI(E)中国科学引文数据库(CSCD)1ARTICLE133-364
Sneutrino DM in the NMSSM with inverse seesaw mechanism
No full textIn supersymmetric theories like the Next-to-Minimal Supersymmetric Standard Model (NMSSM), the lightest neutralino with bino or singlino as its dominant component is customarily taken as dark matter (DM) candidate. Since light Higgsinos favored by naturalness can strength the couplings of the DM and thus enhance the DM-nucleon scattering rate, the tension between naturalness and DM direct detection results becomes more and more acute with the improved experimental sensitivity. In this work, we extend the NMSSM by inverse seesaw mechanism to generate neutrino mass, and show that in certain parameter space the lightest sneutrino may act as a viable DM candidate, i.e. it can annihilate by multi-channels to get correct relic density and meanwhile satisfy all experimental constraints. The most striking feature of the extension is that the DM-nucleon scattering rate can be naturally below its current experimental bounds regardless of the higgsino mass, and hence it alleviates the tension between naturalness and DM experiments. Other interesting features include that the Higgs phenomenology becomes much richer than that of the original NMSSM due to the relaxed constraints from DM physics and also due to the presence of extra neutrinos, and that the signatures of sparticles at colliders are quite different from those with neutralino as DM candidate.National Natural Science Foundation of China (NNSFC) [11575053]SCI(E)ARTICLE1
Classical mechanics and quantum mechanics
No full textThe Newton equation of motion is derived from quantum mechanics.Physics, MultidisciplinarySCI(E)中国科学引文数据库(CSCD)2ARTICLE5685-6884
Policy-driven Data Sharing over Attribute-Based Encryption supporting Dual Membership
No full textAttribute-Based Encryption (ABE) plays an important role in current secure data sharing through fine-grained customizable policies. However, the existing ABE schemes only support simple predicates, = and ≠, but cannot express a more general membership predicates, ∈ and ∉, in policies. The low expressivity of ABE will enlarge the ciphertext storage and reduce the communication efficiency. To overcome this problem, we propose an ABE supporting Dual Membership (DM-ABE). The core problem for implementing this scheme is how to use cryptographic methods to decide the membership between the verified element and the given set. In order to solve this problem, we design a cryptographic algorithm, called Secure Decision of Membership (SDM), based on aggregation functions. In this algorithm, any set can be aggregated into one cryptographic element, and the verified element and the given set can be converted into another cryptographic element in decision process. The membership between them can be decided by the above two cryptographic elements. Furthermore, we construct the DM-ABE by using SDM. Because of the good expressivity of our DM-ABE, we further propose a novel cryptographic data sharing framework by integrating DM-ABE and attribute-based access control to provide fine-grained access control and security protection for private data. In the security proof of DM-ABE, we prove that the DM-ABE satisfies the semantic security against chosen-plaintext attacks under the DBDHE assumption in the standard model through a unified way, considering both two encryption methods for ∈ and ∉ at the same time. Finally, we analyze our scheme in terms of time and space complexity, and compare it with some existing schemes. The results show that our DM-ABE has a better expressive ability on the boolean logic of general membership predicates, ∈ and ∉.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Cyber Securit
A double dissociation between the effects of sub-pyrogenic systemic inflammation and hippocampal lesions on learning
No full textImmune system activation has been found to affect the function of the hippocampus. Sub-pyrogenic systemic inflammation impairs performance of species-typical behaviours that are also disrupted by hippocampal lesions in rodents. In a series of experiments the effect of a low, sub-pyrogenic dose of lipopolysaccharide (LPS) on hippocampus-dependent learning and memory was tested. LPS failed to impair hippocampus-dependent spatial reference memory and working memory. However, LPS affected learning a simple side-discrimination task in which an arm of a T-maze was rewarded (correct arm), and the other arm was never rewarded (incorrect arm). Whereas LPS actually enhanced performance when reward was available on every trial in the correct arm, LPS impaired learning when the correct arm was rewarded on 50% of trials. Hippocampal lesions did not impair either the continuous or partial reinforcement versions of the task. These results demonstrate that a low, sub-pyrogenic dose of LPS can impair cognitive function, but can, depending on the demands of the task, also facilitate learning. However, the double dissociation between the effects of LPS and hippocampal lesions demonstrate that sub-pyrogenic inflammation does not affect learning by disrupting hippocampal function.<br/
Constraining the Inner Galactic DM Density Profile with H.E.S.S.
No full text© 2024 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).In this short review, corresponding to a talk given at the conference “Cosmology 2023 in Miramare”, we combine an analysis of five regions observed by H.E.S.S. in the Galactic Center, intending to constrain the Dark Matter (DM) density profile in a WIMP annihilation scenario. For the analysis, we include the state-of-the-art Galactic diffuse emission Gamma-optimized model computed with DRAGON and a wide range of DM density profiles from cored to cuspy profiles, including different kinds of DM spikes. Our results are able to constrain generalized NFW profiles with an inner slope ≳1.3 . When considering DM spikes, the adiabatic spike is completely ruled out. However, smoother spikes given by the interactions with the bulge stars are compatible if ≲0.8 , with an internal slope of sp-stars=1.5.This work has been supported by the grants PID2021-125331NB-I00, PID2022-139841NB-I00, and CEX2020-001007-S, funded by MCIN/AEI/10.13039/501100011033, by “ERDF A way of making Europe”, and the MULTIDARK Project RED2022-134411-T. The author’s contribution to this work has been supported by the FPI Severo Ochoa PRE2021-099137 grant.With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2020-001007-S).Peer reviewe
Diabetes mellitus (DM) related lower extremity amputations (LEA) rate and risk factors.
No full textAuthor: Ieva Vasiliūtė Title: Diabetes mellitus (DM) related lower extremity amputations (LEA) rate and risk factors. Aim: To investigate LEA rate and risk factors in patients with DM. Objectives: To evaluate DM related LEA rate. To determine DM related LEAs levels and patients demographic factors relation. To determine DM related LEAs levels and type of DM relation. To determine DM related LEAs levels and DM duration, body mass index (BMI), glycated hemoglobin (HbA1c) meanings relation. To evaluate expected mathematically based risk factors. Methods: Retrospective medical records study of 153 patients with DM, who underwent LEAs at the Hospital of Lithuanian University of Health Sciences Kaunas clinics was performed during the 2012 01 01 – 2014 12 31 period. Statistical analysis was performed using the standard SPSS 20.0 program. Results: 33,33% of legs amputations occured among people with DM and 66,67% of them were male (p<0,001). Major LEAs were performed mostly in patients with type 2 DM (86,96%) than those with type 1 DM (p<0,001). Male patients LEAs were performed in patients suffering for shorter duration of DM than in women (19,18 m. (±95% PI 16,71-21,65) vs. 23,36 m. (±95% PI 20,07-26,65), p=0,053). Patients with type 2 DM underwent LEAs had DM for shorter durations (16,19 m. (±95% PI 14,32-18,06)) than those with type 1 DM patients (31,43 m. (±95% PI 28,40-34,45)) ( p<0,001). Major LEAs remove patients had BMI (32,86±5,55 kg/m2) than minor LEAs remove patients (29,13±5,91 kg/m2) (p=0,027). No significant relation was found with amputation level and HbA1c average (p=0,246). DM related eye damage increases the risk of minor LEAs 3,10 times (p=0,001). Obesity/overweight the risk of major LEAs increases 5,65 times (p=0,036) and 2,56 times with obliterate atherosclerosis (p=0,006). Patients with type 2 DM have a 3,2 times (p=0,002) higher risk of undergoing major LEA. Conclusions: A third of patients who had undergone LEAs had DM. Amputations were carried out more frequently in men. DKA arose more often in patients with type 2 DM. LEAs were performed a shorter duration male DM patients. Type 2 DM patients suffered LEAs nearly 2 times shorter duration. Major LEAs experienced patients had a higher BMI. The average of HbA1c is not significantly related with amputation levels. DM related eye damage increases the minor LEAs risk by 3,10 times. Obesity/being overweight increases the risk of major LEAs 5,65 times, obliterate atherosclerosis - 2,56 times. Patients with type 2 DM have a 3,2 times higher risk of major LEA
Rats with hippocampal lesions learn about allocentric place cues in a non-navigational task.
No full textHippocampal-lesioned rats (HPC) and sham controls (SH) learned constant-negative visual discriminations among scenes in a Y-maze. Any arm could be start arm for a trial. Two choice scenes ("constant" and "variable") were shown in the other arms. In Experiment 1, each problem had 2 constants. One or the other constant appeared on every trial, and the variable changed every trial; choosing the variable was rewarded. There were 4 problem types. Each constant might be always in a given direction from the start arm (added egocentric [Ego] cue), always in a given maze arm (added allocentric [Allo] cue), both, or neither. SH rats' visual learning was enhanced by Ego and by Allo cues. HPC rats' visual learning was enhanced by Ego cues, and by Allo cues, but only if there was no Ego cue. Experiment 2 confirmed that Allo cues helped HPC rats as much as SH, in the absence of Ego cues. Rats with HPC lesions can learn about allocentric place cues when navigation and idiothetic cue control are not required
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