Double beta decay is indispensable to solve the question of the neutrino mass matrix together with ν oscillation experiments. Recent analysis of the most sensitive experiment since nine years—the HEIDELBERG-MOSCOW experiment in Gran-Sasso—yields a first indication for the neutrinoless decay mode. This result is the first evidence for lepton number violation and proves the neutrino to be a Majorana particle. We give the present status of the analysis in this report. It excludes several of the neutrino mass (...) scenarios allowed from present neutrino oscillation experiments—only degenerate scenarios and those with inverse mass hierarchy survive. This result allows neutrinos to still play an important role as dark matter in the Universe. To improve the accuracy of the present result, considerably enlarged experiments are required, such as GENIUS. A GENIUS Test Facility has been funded and will come into operation by early 2003. (shrink)

The present experimental status in the search for neutrinoless double beta decay is reviewed, with emphasis on the first indication for neutrinoless double beta decay found in the HEIDELBERG-MOSCOW experiment, giving first evidence for lepton number violation and a Majorana nature of the neutrinos. Future perspectives of the field are briefly outlined.

A large Hilbert space is used for the calculation of the nuclear matrix elements governing the light neutrino mass mediated mode of neutrinoless double beta decay (Ovββ-decay) of76Ge,100Mo,116Cd,128Te, and136Xe within the proton-neutron quasiparticle random phase approximation (pn-QRPA) and the renormalized QRPA with proton-neutron pairing (full-RQRPA) methods. We have found that the nuclear matrix elements obtained with the standard pn-QRPA for several nuclear transitions are extremely sensitive to the renormalization of the particle-particle component of the residual interaction of (...) the nuclear hamiltonian. Therefore the standard pn-QRPA does not guarantee the necessary accuracy to allow us to extract a reliable limit on the effective neutrino mass. This behavior already known from the calculation of the two-neutrino double beta decay matrix elements, manifests itself in the neutrinoless double-beta decay but only if a large model space is used. The full-RQRPA, which takes into account proton-neutron pairing and considers the Pauli principle in an approximate way, offers a stable solution in the physically acceptable region of the particle-particle strength. In this way more accurate values on the effective neutrino mass have been deduced from the experimental lower limits of the half-lifes of neutrinoless double beta decay. (shrink)

In 1934, Enrico Fermi proposed a theory of beta decay. Although it was supported by existing experimental evidence, a more detailed examination revealed discrepancies. Emil Konopinski and George Uhlenbeck proposed an alternative theory that better fit the results and was accepted by the physics community. It was later realized that both the experimental results and the experiment-theory comparison were incorrect. When both problems were corrected, in part by the work of Konopinski and Uhlenbeck themselves, Fermi’s theory was supported. (...) As Konopinski publicly stated in a 1943 review article, “Thus, the evidence of the spectra, which has previously comprised the sole support for the K-U theory, now definitely fails to support it”. (shrink)

A short review is given of three experimental works on tests of the Pauli Exclusion Principle (PEP) in which the author has been involved during the last 10 years. In the first work a search for anomalous carbon atoms was done and a limit on the existence of such atoms was determined, $^{12}\tilde{\mathrm{C}}$ /12C <2.5×10−12. In the second work PEP was tested with the NEMO-2 detector and the limits on the violation of PEP for p-shell nucleons in 12C were obtained. (...) Specifically, transitions to the fully occupied 1s 1/2-shell yielded a limit of 4.2×1024 y for the process with the emission of a γ-quantum. Similarly limits of 3.1×1024 y for β − and 2.6×1024 y for β + Pauli-forbidded transition of 12C → 12Ñ( $^{12}\tilde{\mathrm{B}}$ ) are reported. In the third work it was assumed that PEP is violated for neutrinos, and thus, neutrinos obey at least partly the Bose-Einstein statistics. Consequences of the violation of the exclusion principle for double beta decays were considered. This violation strongly changes the rates of the decays and modifies the energy and angular distributions of the emitted electrons. It was shown that pure bosonic neutrinos are excluded by the present experimental data. In the case of partly bosonic neutrinos the analysis of the existing data allows one to put an upper bound for sin 2 χ<0.6. The sensitivity of future measurements is also evaluated. (shrink)

ABSTRACT Our aim in this article is to offer a new justification for preferring theories that are more quantitatively parsimonious than their rivals. We discuss cases where it seems clear that those involved opted for more quantitatively parsimonious theories. We extend previous work on quantitative parsimony by offering an independent probabilistic justification for preferring the more quantitatively parsimonious theories in particular episodes of theory choice. Our strategy allows us to avoid worries that other considerations, such as pragmatic factors of computational (...) tractability and so on, could be the driving ones in the historical cases under consideration. _1_ Introduction _2_ Three Desiderata _2.1_ Limiting _2.2_ Robustness _2.3_ Breadth _2.3.1_ A limited success for Baker _2.3.2_ Rejecting Baker’s analysis _2.4_ The proposal _3_ Probabilistically Additive Hypotheses and a Bayesian Account: The Limpid Rationale Relativized and Reconsidered _3.1_ Neutrinos and beta decay _3.2_ Avogadro’s hypothesis _3.3_ Postulation of Neptune _4_ Conclusion. (shrink)

Although chemical phenomena are primarily associated with electrons in atoms, ions, and molecules, the masses, charges, spins, and other properties of the nuclei in these species contribute significantly as well. Isotopes, for instance, have proven invaluable in chemistry, in particular the elucidation of reaction mechanisms. Elements with unstable nuclei, for example carbon-14 undergoing beta decay, have enriched chemistry and many other scientific disciplines. The nuclei of all elements have a much more subtle and largely unknown effect on chemical (...) phenomena. All nuclei are innately chiral and, because electrons can penetrate nuclei, all atoms and molecules are likewise chiral. This article describes in considerable detail the discovery of chiral nuclei, how this unusual chirality may influence the chemical behavior of atoms and molecules, and how atomic chirality may have been responsible for the synthesis of optically active molecules in the pre-biotic world. (shrink)

Baker argues that quantitative parsimony—the principle that hypotheses requiring fewer entities are to be preferred over their empirically equivalent rivals—is a rational methodological criterion because it maximizes explanatory power. Baker lends plausibility to his account by confronting it with the example of postulating of the neutrino in order to resolve a discrepancy in Beta decay experiments. Baker’s account is initially attractive, but I argue that its details are problematic and that it yields undesirable consequences when applied to the (...) case of astrophysical dark matter. Baker has not succeeded in showing why quantitative parsimony is a theoretical virtue. (shrink)

Nelson’s stochastic quantum mechanics provides an ideal arena to test how the Born rule is established from an initial probability distribution that is not identical to the square modulus of the wavefunction. Here, we investigate numerically this problem for three relevant cases: a double-slit interference setup, a harmonic oscillator, and a quantum particle in a uniform gravitational field. For all cases, Nelson’s stochastic trajectories are initially localized at a definite position, thereby violating the Born rule. For the double slit and (...) harmonic oscillator, typical quantum phenomena, such as interferences, always occur well after the establishment of the Born rule. In contrast, for the case of quantum particles free-falling in the gravity field of the Earth, an interference pattern is observed before the completion of the quantum relaxation. This finding may pave the way to experiments able to discriminate standard quantum mechanics, where the Born rule is always satisfied, from Nelson’s theory, for which an early subquantum dynamics may be present before full quantum relaxation has occurred. Although the mechanism through which a quantum particle might violate the Born rule remains unknown to date, we speculate that this may occur during fundamental processes, such as beta decay or particle-antiparticle pair production. (shrink)

We present an exactly soluble electron trajectory that permits an analysis of the soft (deep infrared) radiation emitted, the existence of which has been experimentally observed during beta decay via lowest order inner bremsstrahlung. Our treatment also predicts the time evolution and temperature of the emission, and possibly the spectrum, by analogy with the closely related phenomenon of the dynamic Casimir effect.

Quantum mechanics was initiated with the object of allowing only observable concepts to enter into the theory. The new mechanics has, however, inherited the old difficulty with the conservation laws involved in beta decay, and this led Pauli, about 1931, to introduce the idea of the neutrino, with the object of reconciling the facts of beta decay with the conservation laws. The neutrino, as it was proposed by Pauli and as accepted today, is a particle devoid (...) both of mass and charge, but having a spin 1/2 and obeying the Fermi statistics. In 1934 Fermi founded his theory of beta disintegration based on the neutrino. The Fermi theory assumes that this hypothetical particle is emitted simultaneously with the disintegrating electron and carries off the excess energy, thereby reconciling the conservation laws with beta disintegration. It will be remembered that the continuous distribution in energy of the beta particles is such that, except at the maximum energy end point of the beta spectra, there is more energy available from the disintegration than is emitted in the form of beta particles. (shrink)

This book tells the curious story of an unexpected finding that sheds light on a crucial moment in the development of physics: the discovery of artificial radioactivity induced by neutrons. The finding in question is a notebook, clearly written in Fermi's handwriting, which records the frenzied days and nights that Fermi spent experimenting alone, driven by his theoretical ideas on beta decay. The notebook was found by the authors while browsing through documents left by Oscar D'Agostino, the chemist (...) among Fermi's group. From Fermi's notes, they reconstruct with skill and expertise the detailed timeline of the critical days leading up to his vital discovery. While much is already known about the road that led Fermi to his important result, this is the first time that it has been possible to reconstruct precisely when and how the initial evidence of neutron-induced decay was obtained. In relating this fascinating story, the book will be of great interest not only to those with a passion for the history of science but also to a wider audience. (shrink)

Advocates of scientic realism typically respond to the challenge of the pessimistic meta-induction by turning to the history of science. The episode most frequently discussed is the shift from Fresnel's wave theory of light to Maxwell's electromagnetism. This particular history is taken to represent one of the hardest problems for the realist, for while it exhibits continuity on the empirical level, it simultaneously represents a dramatic shift in ontology. Thus, various authors have proposed methods for defeating the pessimistic meta-induction based (...) solely on consideration of the Fresnel-Maxwell case. In this paper, I present another case study from physics--Fermi's 1934 theory of beta-decay and the ensuing search for a universal description of weak interactions. I argue that the degree of success of two recent proposals for scientic realism--that of John Worrall (1989, 1994, 2007) and Juha Saatsi (2005)--changes importantly in light of this new case study. (shrink)

Social constructionists believe that experimental evidence plays a minimal role in the production of scientific knowledge, while rationalists such as myself believe that experimental evidence is crucial in it. As one historical example in support of the rationalist position, I trace in some detail the theoretical and experimental research that led to our understanding of beta decay, from Enrico Fermi’s pioneering theory of 1934 to George Sudarshan and Robert Marshak’s and Richard Feynman and Murray Gell-Mann’s suggestion in 1957 (...) and 1958, respectively, of the V–A theory of weak interactions. This is not a history of an unbroken string of successes, but one that includes incorrect experimental results, incorrect experiment-theory comparisons, and faulty theoretical analyses. Nevertheless, we shall see that the constraints that Nature imposed made the V–A theory an almost inevitable outcome of this theoretical and experimental research. (shrink)

Wolfgang Pauli first suggested the existence of what we now call the neutrino in order to preserve the law of conservation of energy. Previously, in 1911, James Chadwick had demonstrated that in the radioactive process called beta decay the emitted "beta particle" (now known to be an electron) was emitted with some random amount of its kinetic energy missing. Instead of the expected sharp spike of well-defined kinetic energy, a sample of many such emitted electrons showed that (...) their kinetic energies were distributed over a broad bump-like distribution. (shrink)

The age of minerals determined by radioactive methods agrees roughly with the age of the galaxy. This suggests that radioactive alpha-decay constants have probably changed by less than a factor of 3 or 4 during the last 3 or 4 × l09 years. It is shown that this implies that many ‘Constants of Nature’, particularly e, h and c probably change more slowly than 10−12 parts per year. The meson coupling constant also appears to change more slowly than this (...) and the beta-coupling constants by less than 10−9 parts per year. (shrink)

Name der Zeitschrift: Byzantinische Zeitschrift Jahrgang: 107 Heft: 1 Seiten: 37-50.

Stroke remains one of the leading causes of various disabilities, including debilitating motor and language impairments. Though various treatments exist, post-stroke impairments frequently become chronic, dramatically reducing daily life quality, and requiring specific rehabilitation. A critical goal of chronic stroke rehabilitation is to induce, usually through behavioral training, experience-dependent plasticity processes in order to promote functional recovery. However, the efficiency of such interventions is typically modest, and very little is known regarding the neural dynamics underpinning recovery processes and possible biomarkers (...) of their efficiency. Some studies have emphasized specific alterations of excitatory–inhibitory balance within distributed neural networks as an important recovery correlate. Neural processes sensitive to these alterations, such as task-dependent oscillatory activity in beta as well as alpha bands, may be candidate biomarkers of chronic stroke functional recovery. In this review, we discuss the results of studies on motor and language recovery with a focus on oscillatory processes centered around the beta band and their modulations during functional recovery in chronic stroke. The discussion is based on a framework where task-dependent modulations of beta and alpha oscillatory activity, generated by the deep cortical excitatory–inhibitory microcircuits, serve as a neural mechanism of domain-general top-down control processes. We discuss the findings, their limitations, and possible directions for future research. (shrink)

Alpha-beta pruning is a technique for pruning trees in artificial intelligence game-playing. This note draws an analogy between the technique, which is, in essence, an application of many-valued logic to the cut-off of the evaluation of conditionals in computer programs (for efficiency).

The RNA-binding protein, UPF1, is best known for its central role in the nonsense-mediated RNA decay pathway. Feng et al. now report a new function for UPF1—it is an E3 ubiquitin ligase that specifically promotes the decay of a key pro-muscle transcription factor: MYOD. UPF1 achieves this through its RING-like domain, which confers ubiquitin E3 ligase activity. Feng et al. provide evidence that the ability of UPF1 to destabilize MYOD represses myogenesis. In the future, it will be important (...) to define other protein substrates of UPF1-driven ubiquitination and to determine whether this biochemical activity is responsible for some of UPF1's previously defined biological functions, including in development and stress responses. The exciting findings presented by Feng et al. open up the possibility that protein turnover and RNA turnover are coupled processes. The RNA-binding protein, UPF1, is best known for its central role in the nonsense-mediated RNA decay pathway. Here we discuss a new role for UPF1—it is directly involved in protein decay. This hidden talent raises the possibility that protein turnover and RNA turnover are coupled processes. (shrink)

The beta thymosins are a highly conserved family of strongly polar 5 kDa polypeptides that are widely distributed among vertebrate classes; most are now known to bind to monomeric actin and inhibit its polymerization. One beta thymosin, beta four, (Tβ4) is the predominant form in mammalian cells, present at up to 0.5 mM. Many species are known to produce at least two beta thymosin isoforms, in some cases in the same cell. Their expression can be separately (...) regulated. When present outside the cell, the N‐terminal tetrapeptide of beta four appears to affect cell cycle regulation; beta thymosins or smaller fragments derived from them may have additional regulatory functions. We suggest that many developmental changes in beta thymosin levels within cells and tissues may be related to changes in G‐actin pool size. (shrink)

This paper aims to enhance security in IoT device networks through a visual tool that utilizes three projection techniques, including Beta Hebbian Learning (BHL), t-distributed Stochastic Neighbor Embedding (t-SNE) and ISOMAP, in order to facilitate the identification of network attacks by human experts. This work research begins with the creation of a testing environment with IoT devices and web clients, simulating attacks over Message Queuing Telemetry Transport (MQTT) for recording all relevant traffic information. The unsupervised algorithms chosen provide a (...) set of projections that enable human experts to visually identify most attacks in real-time, making it a powerful tool that can be implemented in IoT environments easily. (shrink)

More than 15 million people have been affected by coronavirus disease 2019 (COVID‐19) and it has caused 640 016 deaths as of July 26, 2020. Currently, no effective treatment option is available for COVID‐19 patients. Though many drugs have been proposed, none of them has shown particular efficacy in clinical trials. In this article, the relationship between the Adrenergic system and the renin‐angiotensin‐aldosterone system (RAAS) is focused in COVID‐19 and a vicious circle consisting of the Adrenergic system‐RAAS‐Angiotensin converting enzyme 2 (...) (ACE2)‐severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) (which is referred to as the “ARAS loop”) is proposed. Hyperactivation of the ARAS loop may be the underlying pathophysiological mechanism in COVID‐19, and beta‐adrenergic blockers are proposed as a potential treatment option. Beta‐adrenergic blockers may decrease the SARS‐CoV‐2 cellular entry by decreasing ACE2 receptors expression and cluster of differentiation 147 (CD147) in various cells in the body. Beta‐adrenergic blockers may decrease the morbidity and mortality in COVID‐19 patients by preventing or reducing acute respiratory distress syndrome (ARDS) and other complications. Retrospective and prospective clinical trials should be conducted to check the validity of the hypothesis. Also see the video abstract here https://youtu.be/uLoy7do5ROo. (shrink)

Noradrenergic pathways are involved in mediating the central and peripheral effects of physiological arousal. The aim of the present study was to investigate the role of noradrenergic transmission in moral decision-making. We studied the effects in healthy volunteers of propranolol (a noradrenergic beta-adrenoceptor antagonist) on moral judgement in a set of moral dilemmas pitting utilitarian outcomes (e.g., saving five lives) against highly aversive harmful actions (e.g., killing an innocent person) in a double-blind, placebo-controlled, parallel group design. Propranolol (40 mg (...) orally) significantly reduced heart rate, but had no effect on self-reported mood. Importantly, propranolol made participants more likely to judge harmful actions as morally unacceptable, but only in dilemmas where harms were ‘up close and personal’. In addition, longer response times for such personal dilemmas were only found for the placebo group. Finally, judgments in personal dilemmas by the propranolol group were more decisive. These findings indicate that noradrenergic pathways play a role in responses to moral dilemmas, in line with recent work implicating emotion in moral decision-making. However, contrary to current theorising, these findings also suggest that aversion to harming is not driven by emotional arousal. Our findings are also of significant practical interest given that propranolol is a widely used drug in different settings, and is currently being considered as a potential treatment for post-traumatic stress disorder in military and rescue service personnel. (shrink)

The Protein Ontology (PRO) is designed as a formal and principled Open Biomedical Ontologies (OBO) Foundry ontology for proteins. The components of PRO extend from a classification of proteins on the basis of evolutionary relationships at the homeomorphic level to the representation of the multiple protein forms of a gene, including those resulting from alternative splicing, cleavage and/or posttranslational modifications. Focusing specifically on the TGF-beta signaling proteins, we describe the building, curation, usage and dissemination of PRO. PRO provides a (...) framework for the formal representation of protein classes and protein forms in the OBO Foundry. It is designed to enable data retrieval and integration and machine reasoning at the molecular level of proteins, thereby facilitating cross-species comparisons, pathway analysis, disease modeling and the generation of new hypotheses. (shrink)

As it is well known, mobile phones have become a basic gadget for any individual that usually stores sensitive information. This mainly motivates the increase in the number of attacks aimed at jeopardizing smartphones, being an extreme concern above all on Android OS, which is the most popular platform in the market. Consequently, a strong effort has been devoted for mitigating mentioned incidents in recent years, even though few researchers have addressed the application of visualization techniques for the analysis of (...) malware. Within this field, the present work proposes the extension of a new technique called Hybrid Unsupervised Exploratory Plots to visualize Android malware datasets. More precisely, the novel Beta-Hebbian Learning (BHL) method is applied for the first time and validated under the frame of Hybrid Unsupervised Exploratory Plots, in conjunction with clustering methods. The informative visualization achieved provides a picture of the structure of the malware families, allowing subsequent analysis of their organization. To validate the Hybrid Unsupervised Exploratory Plot extension and its tuning, the popular Android Malware Genome dataset has been used in the experimental setting. Promising results have been obtained, suggesting that BHL applied in combination with clustering techniques in Hybrid Unsupervised Exploratory Plots are a viable resource for the visualization of malware families. (shrink)

Neurosteroid 17 beta-estradiol (E2) is a steroid synthesized de novo in the nervous system that might influence neuronal activity and behavior. Nevertheless, the impact of E2 on the functioning of those neural systems in which it is slightly synthesized is less questioned. The vestibulo-ocular reflex (VOR) adaptation, may provide an ideal arena for investigating this issue. Indeed, E2 modulates cerebellar parallel fiber-Purkinje cell synaptic plasticity that underlies encoding of VOR adaptation. Moreover, aromatase expression in the cerebellum of adult rodents (...) is maintained at very low levels and localized to Purkinje cells. The significance of age-related maintenance of low levels of aromatase expression in the cerebellum on behavior, however, has yet to be explored. Our aim in this study was to determine whether E2 synthesis exerts an effective and persistent modulation of VOR adaptation in adult male rats. To answer this question, we investigated the acute effect of blocking E2 synthesis on gain increases and decreases in VOR adaptation using an oral dose (2.5 mg/kg) of the aromatase inhibitor Letrozole in peri-pubertal and post-pubertal male rats. We found that Letrozole acutely impaired gain increases and decreases in VOR adaptation without altering basal ocular-motor performance and that these effects were similar in peri-pubertal and post-pubertal rats. Thus, in adult male rats neurosteroid E2 effectively modulates VOR adaptation in both of the periods studied. These findings imply that the adult cerebellum uses E2 synthesis for modulating motor memory formation and suggest that low and extremely localized E2 production may play a role in adaptive phenomena. (shrink)

In three recent articles it was shown that β‐catenin is crucial for the establishment and the maintenance of the overall polarity and especially for the character ‘posterior’ in planarians. If the transcription of the β‐catenin gene was silenced by RNA interference, the overall polarity is lost, and in regenerating fragments a posterior blastema displays anterior characters by forming eyes and anterior ganglia. An attempt is made to integrate these new data, well‐known older observations, and observations from other regenerating systems into (...) an outline of a model that will clarify our current understanding as well as highlight areas still to be developed. (shrink)

Climate change and the failure of crops are significant but overlooked events in the history of heredity. Bad weather and dangerously low harvests provided momentum and urgency for answers to questions about how best to improve and acclimatize staple varieties. In the 1790s, a series of crop failures in Britain led to the popularization of and widespread debate over Thomas Andrew Knight’s suggestion that poor weather was in fact largely unconnected to the bad harvests. Rather, Knight argued, Britain’s older varieties—particularly (...) its fruit trees—were coming to the natural end of their lifespans. At a period when Britain was trying to maximize its agricultural land usage, Knight campaigned that his fellow farmers ought to set aside land and resources in order to cultivate new varieties—an expensive and time-consuming procedure—in order to avoid disaster. In this paper, I argue that Knight’s lifelong commitment to his position demonstrates the role played by changes in climate and weather on popular understandings of plant heredity. Further, drawing upon the historiography of Britain’s climate and agriculture, I show that despite reliable weather and good harvests, Knight’s campaign survived for several decades before the continued health of Britain’s trees was finally treated as sufficient evidence to dispense with Knight’s warnings. This case provides a means of thinking about the history of heredity as it is shaped and impacted by changes in climate and local conditions. (shrink)

Phi Beta Kappa Romanell Lectures, given at Michigan State University, February 2008.

In the paper, the role of a citizen, a public official, and an observer in the reproduction of bribery as a social norm are each analyzed. To make the analysis of this cellular-social form of corruption, three variables are incorporated: the agent’s perception of how widespread the corruption is, the agent’s available resources with which to act, and the role of moral values. Later, some scenarios of normalization and denormalization of corruption are explored, making different assumptions regarding the analysis and (...) assignment of agents to different roles in the interactions. What was found is that power relations among corrupt and non-corrupt agents are key for understanding the social reproduction of bribery, where inequality might facilitate the social reproduction of corruption. The role of the observer of the interaction of bribe-givers, bribe-takers, and bribe-resisting agents was also found to potentially tip the balance in the direction of normalization or denormalization of bribery. Hence, giving the observer tools to intervene in these interactions becomes essential to combat corruption. (shrink)

In Social Decay and Transformation social and political critic Samuel Farber presents an analysis of social decline that has been missing from the contemporary scene: a view from the Left, one which draws from the ideas and traditions of the Enlightenment's left wing. Using a comparative approach to situate his theoretical conclusions in historical circumstances, Farber looks at the working class and temperance movements, civil rights rebellions and the Black Panthers, and the cultural revolutions of 1920s Russia and the (...) Bolsheviks. Providing carefully reasoned interrogations of contemporary thinkers such as James C. Scott and Robin D. G. Kelley, Farber clarifies the discussions on social decay currently taking place, adding an important voice of the Left to the current debate. (shrink)

Although the biological bases of forgetting remain obscure, the consensus among cognitive psychologists emphasizes interference processes, rejecting decay in accounting for memory loss. In contrast to this view, recent advances in understanding the neurobiology of long-term memory maintenance lead us to propose that a brain-wide well-regulated decay process, occurring mostly during sleep, systematically removes selected memories. Down-regulation of this decay process can increase the life expectancy of a memory and may eventually prevent its loss. Memory interference usually (...) occurs during certain active processing phases, such as encoding and retrieval, and will be stronger in brain areas with minimal sensory integration and less pattern separation. In areas with efficient pattern separation, such as the hippocampus, interference-driven forgetting will be minimal, and, consequently, decay will cause most forgetting. (shrink)

Nonsense‐mediated RNA decay (NMD) represents an established quality control checkpoint for gene expression that protects cells from consequences of gene mutations and errors during RNA biogenesis that lead to premature termination during translation. Characterization of NMD‐sensitive transcriptomes has revealed, however, that NMD targets not only aberrant transcripts but also a broad array of mRNA isoforms expressed from many endogenous genes. NMD is thus emerging as a master regulator that drives both fine and coarse adjustments in steady‐state RNA levels in (...) the cell. Importantly, while NMD activity is subject to autoregulation as a means to maintain homeostasis, modulation of the pathway by external cues provides a means to reprogram gene expression and drive important biological processes. Finally, the unanticipated observation that transcripts predicted to lack protein‐coding capacity are also sensitive to this translation‐dependent surveillance mechanism implicates NMD in regulating RNA function in new and diverse ways. (shrink)