Memory Gap Research Articles

Kindergarten Black–White Test Score Gaps

Black–white test score gaps form in early childhood and widen over elementary school. Sociologists have debated the roles that socioeconomic status (SES) and school quality play in explaining these patterns. In this study, I replicate and extend past research using new nationally representative data from the Early Childhood Longitudinal Study–Kindergarten Class of 2010–2011. I find black–white test score gaps at kindergarten entry in 2010 in reading ( SD = .32), math ( SD = .54), and working memory ( SD = .52 among children with valid scores). Math and reading gaps widened by approximately .06 standard deviations over kindergarten, but the working memory gap was constant. Multivariate regressions show that student SES explained the reading gap at school entry, but gap decompositions suggest that school quality differences were responsible for the widening of the reading gap over kindergarten. SES explained much of the math gap at school entry, but the widening of the math gap could not be explained by SES, school quality, or other hypotheses.

Teaching silence in the schoolroom: whither national history in Sierra Leone and El Salvador?

This article addresses the divergent cultures of silence and memorialisation about the civil wars in Sierra Leone and El Salvador, and examines the role that sites of remembering and forgetting play in crafting post-war citizens. In the formal education sector the ministries of education in each country have taken different approaches to teaching the history of the war, with Sierra Leone emphasising forgetting and El Salvador geared towards remembering war history. In both countries nongovernmental actors, particularly peace museums, are filling the memory gap. Drawing on ethnographic fieldwork in each country, the article documents how the culture of silence that pervades Sierra Leone enables a progress-driven ‘looking forward’ without teaching the past, while El Salvador is working on weaving a culture of memorialisation into its democratisation process. The article argues that knowledge about civil war history can raise young people’s awareness of the consequences of violence and promote civic engagement in its deterrence.

Power-efficient prefetching on GPGPUs

The graphics processing unit (GPU) is the most promising candidate platform for achieving faster improvements in peak processing speed, low latency and high performance. The highly programmable and multithreaded nature of GPUs makes them a remarkable candidate for general purpose computing. However, supporting non-graphics computing on graphics processors requires addressing several architectural challenges. In this paper, we focus on improving performance by better hiding long waiting time for transferring data from the slow global memory. Furthermore, we show that the proposed method can reduce power and energy. Reduction in access time to off-chip data has a noticeable role in reducing waiting time and the percentage of unutilized elements. Also, using processing elements in a suitable manner to prefetch data during stall times bridges the memory gap in an energy-efficient manner, and consequently leads to less power and energy consumption. Simulation results show that we can potentially improve instruction per cycle (IPC) up to 24.76 %. Moreover, results show that power, energy and energy efficiency improve by up to 22.47, 24.72 and 36.01 %, respectively.

Transient global amnesia.

Transient global amnesia (TGA) is a sudden and severe anterograde memory disturbance accompanied by various degrees of retrograde amnesia and sometimes executive dysfunction. TGA affects elderly individuals and men and women equally. During the episode, patients cannot recall novel episodic information and therefore repeatedly ask the same questions. They are not fully oriented to space and time. Diagnostic criteria first established in 1985, and elaborated in 1990, demand that there is no clouding of consciousness, other impairments of cognition, or a history of epilepsy or head trauma. An episode of TGA resolves within 24 h leaving a memory gap for the length of the attack. While in rare cases TGA might happen repeatedly, it mostly occurs as a single attack. TGA is considered a benign disorder as memory deficits resolve completely and do not lead to long-term sequelae. In up to 90% of reported TGA cases, a precipitating event - mainly described as physical or emotional stress - is present. The cause of TGA has been a matter of long-standing debate among researchers. In search of an answer, several possible causes (ischemia, migraine, epileptic seizures, or, more recently, a disturbance of venous hemodynamics) have been hypothesized. However, to date there is no scientific proof of any of these mechanisms. By using diffusion-weighted MRI 24-48 h after a TGA episode, small dot-like lesions have been detected in the hippocampus. This has led to the implication that the selective vulnerability of CA1 neurons to metabolic stress might play a role in the pathophysiology of TGA.

Delays Induce an Exponential Memory Gap for Rendezvous in Trees

The aim of rendezvous in a graph is meeting of two mobile agents at some node of an unknown anonymous connected graph. In this article, we focus on rendezvous in trees, and, analogously to the efforts that have been made for solving the exploration problem with compact automata, we study the size of memory of mobile agents that permits to solve the rendezvous problem deterministically. We assume that the agents are identical, and move in synchronous rounds. We first show that if the delay between the starting times of the agents is arbitrary , then the lower bound on memory required for rendezvous is Ω (log n ) bits, even for the line of length n . This lower bound meets a previously known upper bound of O (log n ) bits for rendezvous in arbitrary graphs of size at most n . Our main result is a proof that the amount of memory needed for rendezvous with simultaneous start depends essentially on the number ℓ of leaves of the tree, and is exponentially less impacted by the number n of nodes. Indeed, we present two identical agents with O (log ℓ + log log n ) bits of memory that solve the rendezvous problem in all trees with at most n nodes and at most ℓ leaves. Hence, for the class of trees with polylogarithmically many leaves, there is an exponential gap in minimum memory size needed for rendezvous between the scenario with arbitrary delay and the scenario with delay zero. Moreover, we show that our upper bound is optimal by proving that Ω (log ℓ + log log n ) bits of memory are required for rendezvous, even in the class of trees with degrees bounded by 3.

A Scalable High-Performance Virus Detection Processor Against a Large Pattern Set for Embedded Network Security

Contemporary network security applications generally require the ability to perform powerful pattern matching to protect against attacks such as viruses and spam. Traditional hardware solutions are intended for firewall routers. However, the solutions in the literature for firewalls are not scalable, and they do not address the difficulty of an antivirus with an ever-larger pattern set. The goal of this work is to provide a systematic virus detection hardware solution for network security for embedded systems. Instead of placing entire matching patterns on a chip, our solution is a two-phase dictionary-based antivirus processor that works by condensing as much of the important filtering information as possible onto a chip and infrequently accessing off-chip data to make the matching mechanism scalable to large pattern sets. In the first stage, the filtering engine can filter out more than 93.1% of data as safe, using a merged shift table. Only 6.9% or less of potentially unsafe data must be precisely checked in the second stage by the exact-matching engine from off-chip memory. To reduce the impact of the memory gap, we also propose three enhancement algorithms to improve performance: 1) a skipping algorithm; 2) a cache method; and 3) a prefetching mechanism.

Evidence‐based electroconvulsive therapy

Evidence‐based electroconvulsive therapy

P01-407 - Dissociative fugue of the patient of maternity ward - A case report

IntroductionMothers after childbearing are vulnerable to many stress related disorders.Objectiveto emphasize the role of the past obstetric complications, as so present infant pathology as risk factors for the mother's post partum stress related disorders.MethodsThe case analysis.Case descriptionThe thirty-year-old, women left the maternity ward with her baby unnoticed on the fourth day after giving birth. She was referred to psychiatry ward, after finding her by the police. In the past history the patient had spontaneous miscarriage in the first pregnancy. She has waited with her husband 6 years long for the next baby. The second pregnancy was at risk, the labor was premature and the infant has palatoschisis. The mother had difficulties with feeding. She feared about baby's life, and had feeling of being neglected by the staff. In psychiatry ward she did not reveal any symptoms of mental illness. She was interested in her child, however the period of the flight was covered with memory gap. The predominance of immature defense mechanisms, as so mild cognitive dysfunctions were revealed in psychological testing. The dissociative fugue was diagnosed. The patient was discharged without any medication to ambulatory psychotherapy.CommentaryThe interaction of past and present traumatic experiences in the patient with cognitive dysfunctions and immature defense mechanisms could impair ability of post-partum coping with fear about the child and consequently led to the loss of conscious control over the memory. Early diagnosing and supporting problematic patients of the maternity ward is needed.

Competing Narratives, Identity Politics, and Cross-Strait Reconciliation

After nearly sixty years of political confrontation, hopes for cross-Taiwan Strait reconciliation have run high since the traditionally pro-unification Nationalist Party (the Kuomintang, KMT) returned to power in Taiwan in May 2008. However, obstacles to reconciliation remain daunting, due to a fundamental disjuncture between the ideological beliefs of the two sides, in particular because China and Taiwan still lack a shared memory of Taiwanese history that can serve as the foundation for their reconciliation. This article examines a wide variety of sources from Taiwan and China over recent decades. It illustrates their conspicuous memory gap over the history of the island. Cross-Strait reconciliation needs to begin with recognizing rather than ignoring or covering up the memory gap. Dialogue and joint studies should be carried out to better understand each other’s political perspective and emotional appeal associated with historical memory.

To Survive Out-of-Hospital Cardiac Arrest: A Search for Meaning and Coherence

The primary responsibility of prehospital emergency personnel at out-of-hospital cardiac arrests (OHCA) is to provide lifesaving care. Ethical considerations, decisions, and actions should be based in the patient's beliefs about health and well-being. In this article, we describe patients' experiences of surviving OHCA. By using a phenomenological approach, we focus on how OHCA influences patients' well-being over time. Nine survivors were interviewed. Out-of-hospital cardiac arrest is described as a sudden and elusive threat, an awakening in perplexity, and the memory gap as a loss of coherence. Survival means a search for coherence with distressing and joyful understanding, as well as existential insecurity exposed by feelings of vulnerability. Well-being is found through a sense of coherence and meaning in life. The study findings show survivors' emotional needs and a potential for prehospital emergency personnel to support them as they try to make sense of what has happened to them.

Transient Amnesia in a Patient With Left Temporal Tumor

An isolated prolonged episode of transient amnesia can be a major manifestation of transient global amnesia (TGA) and transient epileptic amnesia (TEA). We report a case of transient amnesia associated with a left temporal tumor and try to elucidate the possible mechanism of the amnesia. A 67-year-old right-handed man with the past history of migraine developed a transient declarative amnesia with a permanent memory gap for 5 hours. During the attack, he drove for 100 km flawlessly, but was not aware of his memory deficit. Selective retrograde amnesia during the episode was also observed. Investigations revealed an impaired verbal memory on neuropsychological tests, a possible metastatic tumor in the left temporal lobe by cerebral MRI, isolated wicket temporal spikes in the left mesial temporal area by sphenoidal electroencephalogram (EEG), and an additional brief phase of confusion. No recurrence of a similar attack occurred by 17 months after treatment with radiotherapy and chemotherapy. This case serves to emphasize that transient dense anterograde amnesia resembling TGA might possibly occur as a manifestation of TEA and that there is a risk of subsequent epileptic features. The amnesia in this case also supports the hypothesis of spreading depression in patients with TGA and migraine and could support the epileptic hypothesis for the pathogenesis of TGA.

Mental Status Exam

Back to table of contents Previous article Letters to the EditorFull AccessMental Status ExamKenneth A. Nakdimen, M.D.Kenneth A. NakdimenSearch for more papers by this author, M.D.Published Online:4 May 2007https://doi.org/10.1176/pn.42.9.0023The standard mental status exam's assessment of memory has a blind spot. It doesn't ask patients if they've had recurrent sober memory gaps (dissociative amnesia), which is often the only clue that a patient might have dissociative identity disorder (DID). It leaves it to patients to raise the issue.Why don't undiagnosed DID patients bring up the subject of their memory gaps? First, they don't know its clinical significance (that these might be times that other identities were “out”). Second, they are generally unaware that they've lost time, except when something embarrassing, confusing, or disturbing confronts them with the fact, and they don't like to think about it. Third, they're afraid that telling people they have memory gaps—periods of time they don't remember and when they're not in control of their own behavior—might make people think they're“ crazy.”Why do clinicians need a “clue” (memory gaps) to the presence of DID? What's the mystery? When DID is present, isn't it obvious? If you've ever seen an interview of a known DID patient, weren't the switches from one identity to another something you couldn't miss?Actually, what you see in such an interview is the postdiagnosis picture, not how DID presents. Prediagnosis, alternate identities usually answer to the patient's regular name, because they prefer to remain incognito. They lose that reticence once diagnosis has blown their cover, but all that you would have found prediagnosis (if you had inquired) were memory gaps.Once you discover that your patient does have a history of memory gaps, you can ask about these episodes. For example, after some gaps, a patient finds poems. She agrees that nobody else could have written these poems (which she found among her personal papers), but she doesn't remember writing them; they don't express her views, and they're not even in her handwriting.Keeping the interview focused on these poems will eventually cause a switch to the identity who wrote them. You might ask this identity why she writes poems, her age, and her name. If you then turn the focus away from the poems, or simply address the patient by her regular name, you will prompt a switch back to the regular identity, who has amnesia (a memory gap) for your conversation with the poetry-writing identity.The standard mental status exam does not now, but should, screen for memory gaps (dissociative amnesia). Otherwise, when it comes to diagnosing DID, the clinician will be clueless.New York, N.Y. ISSUES NewArchived

Metabolic mapping of the rat cerebellum during delay and trace eyeblink conditioning

The essential neural circuitry for delay eyeblink conditioning has been largely identified, whereas much of the neural circuitry for trace conditioning has not been identified. The major difference between delay and trace conditioning is a time gap between the presentation of the conditioned stimulus (CS) and the unconditioned stimulus (US) during trace conditioning. It is this time gap or trace interval which accounts for an additional memory component in trace conditioning. Additional neural structures are also necessary for trace conditioning, including hippocampus and prefrontal cortex. This addition of forebrain structures necessary for trace but not delay conditioning suggests other brain areas become involved when a memory gap is added to the conditioning parameters. A metabolic marker of energy use, radioactively labeled glucose analog, was used to compare differences in glucose analog uptake between delay, trace, and unpaired experimental groups in order to identify new areas of involvement within the cerebellum. Known structures such as the interpositus nucleus and lobule HVI showed increased activation for both delay and trace conditioning compared to unpaired conditioning. However, there was a differential amount of activation between anterior and posterior portions of the interpositus nucleus between delay and trace, respectively. Cerebellar cortical areas including lobules IV and V of anterior lobe, Crus I, Crus II, and paramedian lobule also showed increases in activity for delay conditioning but not for trace conditioning. Delay and trace eyeblink conditioning both resulted in increased metabolic activity within the cerebellum but delay conditioning resulted in more widespread cerebellar cortical activation.

Effector-specific fields for motor preparation in the human frontal cortex

We investigated the neural correlates of advance motor preparation in two experiments that required a movement in response to a peripheral visual stimulus. In one experiment (the memory delay paradigm), subjects knew the target location during a preparatory ‘memory delay’ interval; in the other experiment they did not know the target location during a ‘gap period’ (the gap paradigm). In both experiments we further varied the effector that was instructed, either the eye or the forelimb. An area that codes motor preparation should exhibit increases during the memory delay and gap period and such increases should predict some attribute of performance (planning to use the eye or the forelimb). We first identified the frontoparietal visuomotor areas using standard fMRI block designs. Subjects were then scanned using event-related fMRI. With the exception of primary motor cortex (M1), all areas (putative lateral intraparietal area (putLIP), dorsal premotor cortex (PMd), frontal eye field (FEF), ventral frontal eye field (FEFv), supplementary motor area (SMA)) showed gap and memory delay activation for both saccades and pointing. Gap activity in the frontal areas was higher than in the parietal area(s) investigated. The observation that ‘memory delay’ activity was equivalent or less than gap activity in all areas suggests that what is commonly considered to be memory-related responses largely represents advance motor preparation. Certain areas showed increased activation during the gap or memory delay intervals for pointing (PMd, FEF, FEFv) or saccades (SMA, putLIP). These observations suggest an important role of the frontal cortex in advance motor preparation.

Feedback controlled nanocantilever device

A switchable carbon-nanotube-based nanoelectromechanical systems (NEMS) with close-loop feedback is examined. The device consists of a cantilever carbon nanotube clamped to a top electrode and actuated by a bottom electrode. The actuation circuit includes a source and a feedback resistor. The pull-in/pull-out and tunneling characteristics of the system are investigated by means of an electromechanical analysis. The model includes the concentration of electrical charge, at the end of the nanocantilever, and the van der Waals force. The analysis shows that the device has two well-defined stable equilibrium positions as a result of tunneling and the incorporation of a feedback resistor to the circuit. Potential applications of the device include NEMS switches, random-access memory elements, logic devices, electron counters, and gap sensing devices.

Processor-memory coexploration using an architecture description language

Memory represents a major bottleneck in modern embedded systems in terms of cost, power, and performance. Traditionally, memory organizations for programmable embedded systems assume a fixed cache hierarchy. With the widening processor--memory gap, more aggressive memory technologies and organizations have appeared, allowing customization of a heterogeneous memory architecture tuned for specific target applications. However, such a processor--memory coexploration approach critically needs the ability to explicitly capture heterogeneous memory architectures. We present in this paper a language-based approach to explicitly capture the memory subsystem configuration, generate a memory-aware software toolkit, and perform coexploration of the processor--memory architectures. We present a set of experiments using our memory-aware architectural description language (ADL) to drive the exploration of the memory subsystem for the TI C6211 processor architecture, demonstrating cost, performance, and energy trade-offs.

A memory GAP

Pavlovian conditioning of the response to fear has provided an important model for memory formation in mammals. Several studies have begun to identify the key signal-transduction components that provide the molecular basis for this complex neural process. A recent report has revealed that the Rho GTPase and its regulator p190 Rho-GTPase-activating protein (p190 RhoGAP) also play an important regulatory role in fear memory formation.

IPULOC — Exploring dynamic program locality with the instruction processing unit for filling memory gap

Memory gap has become an essential factor influencing the peak performance of high-speed CPU-based systems. To fill this gap, enlarging cache capacity has been a traditional method based on static program locality principle. However, the order of instructions stored in I-Cache before being sent to Data Processing Unit (DPU) is a kind of useful information that has not ever been utilized before. So an architecture containing an Instruction Processing Unit (IPU) in parallel with the ordinary DPU is proposed. The IPU can prefetch, analyze and preprocess a large amount of instructions otherwise lying in the I-Cache untouched. It is more efficient than the conventional prefetch buffer that can only store several instructions for previewing. By IPU, Load Instructions can be preprocessed while the DPU is executing on data simultaneously. It is termed as "Instruction Processing Unit with LOokahead Cache" (IPULOC for short) in which the idea of dynamic program locality is presented. This paper describes the principle of IPULOC and illustrates the quantitative parameters for evaluation. Tools for simulating the IPULOC have been developed. The simulation result shows that it can improve program locality during program execution, and hence can improve the cache hit ratio correspondingly without further enlarging the on-chip cache that occupies a large portion of chip area.

The memory gap and the future of high performance memories

The first main memories to be used on digital computers were constructed using a technology much slower than that used for the logic circuits, and it was taken for granted that there would be a memory gap. Mercury delay line memories spent a lot of their time waiting for the required word to come round and were very slow indeed. CRT (Williams Tube) memories and the core memories that followed them were much better. By the early 1970s semiconductor memories were beginning to appear. This did not result in memory performance catching up fully with processor performance, although in the 1970s it came close. It might have expected that from that point memories and processors would scale together, but this did not happen. This was because of significant differences in the DRAM semiconductor technology used for memories compared with the technology used for circuits. The memory gap makes itself felt when a cache miss occurs and the missing word must be be supplied from main memory. It thus only affects users whose programs do not fit into the L2 cache. As far as a workstation user is concerned, the most noticeable effect of an increased memory gap is to make the observed performance more dependent on the application area than it would otherwise be. Since 1980, the memory gap has been increasing steadily. During the last ten years, processors have been improving in speed by 60% per annum, whereas DRAM memory access has been improving at barely 10%. It may thus be said that, while the memory gap is not at present posing a major problem, the writing is on the wall. On an Alpha 21264 667 MHz workstation (XP1000) in 2000, a cache miss cost about 128 clock cycles. This may be compared with the 8 – 32 clock cycles in the minicomputer and workstations of 1990 [1]. If the memory latency remains unchanged, the number of cycles of processor idle time is doubled with each doubling of speed of the processor. A factor of four will bring us to about 500 clock cycles.

Native Daughters: My Place and Incidents in the Life of a Slave Girl

This essay considers two autobiographies, My Place by Australian writer and painter Sally Morgan (1951-) and Incidents in the Life a Slave Girl by the American abolitionist and ex-slave Harriet Jacobs (1813-1897). The argument is that these texts resemble, illuminate and confirm one another, despite huge differences between their origins in space and time. To study these books together shows that not only are novelists revisiting the fugitive narratives, but autobiographers are, too. The comparison also convinces me that fugitive narratives, or at least some such narratives, are not written from a viewpoint the quintessentially 'other' as William L. Andrews proposes; instead they occupy intimate, intermediate position which I call a thou position. My Place and Incidents in the Life a Slave Girl exhibit a striking likeness, namely, a common origin in struggles to retrieve repressed memories from personal silences and install them in the center public memory. The repressed memory on the private side in both is childhood sexual abuse. On the public side in both is a half-remembered national atrocity, chattel slavery in America and slavery in all but name over aboriginal people in Australia. The American memory gap erases the positive accomplishments Reconstruction, and elides the daily business slaveholding and maintaining the ideology slave-owners from history. Anglo-Australians similarly elide Aboriginal people's labor from their origin myths about their pastoral wealth. The autobiographies considered here disclose close links between those family secrets sexism protects and public atrocities racism excuses. In stories like these, which are between domestic and national crimes, aporias and displacements are rife because the authors struggle against the dominant public narratives. Though all autobiography has rifts and discontinuities, fugitive narratives arguably have more due to the circumstances from which they spring. Autobiography which aims to overturn a repugnant ideology must expose dirty secrets, secrets every ideology has. As Pierre Machery observes in A Theory Literary Production, an ideology is made what it does not mention; it exists because there are things which must not be spoken of (132). The act writing to impugn ideology resembles psychoanalysis because such writing tries to analyze the political unconscious. An autobiographer in so doing probes taboos like analyst. To decode her culture's dreams, she has to pry open ideological silences, those aporias in public discourse, and gouge out new pathways. (Aporia comes from the Greek a, not, and poros, passage or ford. An aporia marks the end the road, hence a logical impass.) Morgan and Jacobs arrive at repeated aporias; they count on sympathy to fill in where narrative falters. They want readers to realize that sexual abuse and political injustice are alike. They expect readers might make the cognitive leap the analogy involves because that ideology which shields the patriarch in his homestead resembles the historiography that masks him and his in national myths. Patricia Williams observes: Self possession in the full sense that expression is the companion to self-knowledge. Yet claiming for myself a heritage the weft whose genesis is my own disinheritance is a profoundly troubling paradox (Signs 6-7). In other words, the impasses that confront autobiographer whose own body is supposed to be illegitimate cast doubt equally on claims to descent and the ability to bear witness. To complain is to risk making yourself a spectacle and confirming the ideology which occludes you; even to tell the facts dispassionately requires a novelist's skill. William L. Andrews frames the problem finding the right rhetorical stance for a fugitive narrative in terms the self and its others: During the ante-bellum era, when black narrative in the United States developed into a highly self-conscious and rhetorically sophisticated tradition, black writers who aimed at a serious hearing knew that the authority they aspired to was predicated on the authenticity that they could project onto and through a text. …