Scaling In-Memory databases on multicores

Current computer systems have evolved from featuring only a single processing unit and limited RAM, in the order of kilobytes or few megabytes, to include several multicore processors, o↵ering in the order of several tens of concurrent execution contexts, and have main memory in the order of several tens to hundreds of gigabytes. This allows to keep all data of many applications in the main memory, leading to the development of inmemory databases. Compared to disk-backed databases, in-memory databases (IMDBs) are expected to provide better performance by incurring in less I/O overhead. In this dissertation, we present a scalability study of two general purpose IMDBs on multicore systems. The results show that current general purpose IMDBs do not scale on multicores, due to contention among threads running concurrent transactions. In this work, we explore di↵erent direction to overcome the scalability issues of IMDBs in multicores, while enforcing strong isolation semantics. First, we present a solution that requires no modification to either database systems or to the applications, called MacroDB. MacroDB replicates the database among several engines, using a master-slave replication scheme, where update transactions execute on the master, while read-only transactions execute on slaves. This reduces contention, allowing MacroDB to o↵er scalable performance under read-only workloads, while updateintensive workloads su↵er from performance loss, when compared to the standalone engine. Second, we delve into the database engine and identify the concurrency control mechanism used by the storage sub-component as a scalability bottleneck. We then propose a new locking scheme that allows the removal of such mechanisms from the storage sub-component. This modification o↵ers performance improvement under all workloads, when compared to the standalone engine, while scalability is limited to read-only workloads. Next we addressed the scalability limitations for update-intensive workloads, and propose the reduction of locking granularity from the table level to the attribute level. This further improved performance for intensive and moderate update workloads, at a slight cost for read-only workloads. Scalability is limited to intensive-read and read-only workloads. Finally, we investigate the impact applications have on the performance of database systems, by studying how operation order inside transactions influences the database performance. We then propose a Read before Write (RbW) interaction pattern, under which transaction perform all read operations before executing write operations. The RbW pattern allowed TPC-C to achieve scalable performance on our modified engine for all workloads. Additionally, the RbW pattern allowed our modified engine to achieve scalable performance on multicores, almost up to the total number of cores, while enforcing strong isolation.

Constitutive activation of Wnt signaling favors generation of memory CD8 T cells.

T cell factor-1 (TCF-1) and lymphoid enhancer-binding factor 1, the effector transcription factors of the canonical Wnt pathway, are known to be critical for normal thymocyte development. However, it is largely unknown if it has a role in regulating mature T cell activation and T cell-mediated immune responses. In this study, we demonstrate that, like IL-7Ralpha and CD62L, TCF-1 and lymphoid enhancer-binding factor 1 exhibit dynamic expression changes during T cell responses, being highly expressed in naive T cells, downregulated in effector T cells, and upregulated again in memory T cells. Enforced expression of a p45 TCF-1 isoform limited the expansion of Ag-specific CD8 T cells in response to Listeria monocytogenes infection. However, when the p45 transgene was coupled with ectopic expression of stabilized beta-catenin, more Ag-specific memory CD8 T cells were generated, with enhanced ability to produce IL-2. Moreover, these memory CD8 T cells expanded to a larger number of secondary effectors and cleared bacteria faster when the immunized mice were rechallenged with virulent L. monocytogenes. Furthermore, in response to vaccinia virus or lymphocytic choriomeningitis virus infection, more Ag-specific memory CD8 T cells were generated in the presence of p45 and stabilized beta-catenin transgenes. Although activated Wnt signaling also resulted in larger numbers of Ag-specific memory CD4 T cells, their functional attributes and expansion after the secondary infection were not improved. Thus, constitutive activation of the canonical Wnt pathway favors memory CD8 T cell formation during initial immunization, resulting in enhanced immunity upon second encounter with the same pathogen.

Biomedical risk assessment as an aid for smoking cessation.

BACKGROUND: A possible strategy for increasing smoking cessation rates could be to provide smokers who have contact with healthcare systems with feedback on the biomedical or potential future effects of smoking, e.g. measurement of exhaled carbon monoxide (CO), lung function, or genetic susceptibility to lung cancer. OBJECTIVES: To determine the efficacy of biomedical risk assessment provided in addition to various levels of counselling, as a contributing aid to smoking cessation. SEARCH STRATEGY: We systematically searched the Cochrane Collaboration Tobacco Addiction Group Specialized Register, Cochrane Central Register of Controlled Trials 2008 Issue 4, MEDLINE (1966 to January 2009), and EMBASE (1980 to January 2009). We combined methodological terms with terms related to smoking cessation counselling and biomedical measurements. SELECTION CRITERIA: Inclusion criteria were: a randomized controlled trial design; subjects participating in smoking cessation interventions; interventions based on a biomedical test to increase motivation to quit; control groups receiving all other components of intervention; an outcome of smoking cessation rate at least six months after the start of the intervention. DATA COLLECTION AND ANALYSIS: Two assessors independently conducted data extraction on each paper, with disagreements resolved by consensus. Results were expressed as a relative risk (RR) for smoking cessation with 95% confidence intervals (CI). Where appropriate a pooled effect was estimated using a Mantel-Haenszel fixed effect method. MAIN RESULTS: We included eleven trials using a variety of biomedical tests. Two pairs of trials had sufficiently similar recruitment, setting and interventions to calculate a pooled effect; there was no evidence that CO measurement in primary care (RR 1.06, 95% CI 0.85 to 1.32) or spirometry in primary care (RR 1.18, 95% CI 0.77 to 1.81) increased cessation rates. We did not pool the other seven trials. One trial in primary care detected a significant benefit of lung age feedback after spirometry (RR 2.12; 95% CI 1.24 to 3.62). One trial that used ultrasonography of carotid and femoral arteries and photographs of plaques detected a benefit (RR 2.77; 95% CI 1.04 to 7.41) but enrolled a population of light smokers. Five trials failed to detect evidence of a significant effect. One of these tested CO feedback alone and CO + genetic susceptibility as two different intervention; none of the three possible comparisons detected significant effects. Three others used a combination of CO and spirometry feedback in different settings, and one tested for a genetic marker. AUTHORS' CONCLUSIONS: There is little evidence about the effects of most types of biomedical tests for risk assessment. Spirometry combined with an interpretation of the results in terms of 'lung age' had a significant effect in a single good quality trial. Mixed quality evidence does not support the hypothesis that other types of biomedical risk assessment increase smoking cessation in comparison to standard treatment. Only two pairs of studies were similar enough in term of recruitment, setting, and intervention to allow meta-analysis.

B and T lymphocyte attenuator regulates CD8+ T cell-intrinsic homeostasis and memory cell generation.

B and T lymphocyte attenuator (BTLA) is a negative regulator of T cell activation, but its function in vivo is not well characterized. Here we show that mice deficient in full-length BTLA or its ligand, herpesvirus entry mediator, had increased number of memory CD8(+) T cells. The memory CD8(+) T cell phenotype resulted from a T cell-intrinsic perturbation of the CD8(+) T cell pool. Naive BTLA-deficient CD8(+) T cells were more efficient than wild-type cells at generating memory in a competitive antigen-specific system. This effect was independent of the initial expansion of the responding antigen-specific T cell population. In addition, BTLA negatively regulated antigen-independent homeostatic expansion of CD4(+) and CD8(+) T cells. These results emphasize two central functions of BTLA in limiting T cell activity in vivo.

Increased numbers of circulating polyfunctional Th17 memory cells in patients with seronegative spondylarthritides

OBJECTIVE: A distinct subset of proinflammatory CD4+ T cells that produce interleukin-17 was recently identified. These cells are implicated in different autoimmune disease models, such as experimental autoimmune encephalomyelitis and collagen-induced arthritis, but their involvement in human autoimmune disease has not yet been clearly established. The purpose of this study was to assess the frequency and functional properties of Th17 cells in healthy donors and in patients with different autoimmune diseases. METHODS: Peripheral blood was obtained from 10 psoriatic arthritis (PsA), 10 ankylosing spondylitis (AS), 10 rheumatoid arthritis (RA), and 5 vitiligo patients, as well as from 25 healthy donors. Synovial tissue samples from a separate group of patients were also evaluated (obtained as paraffin-embedded sections). Peripheral blood cells were analyzed by multiparameter flow cytometry and immunohistochemistry. Cytokine production was examined by enzyme-linked immunosorbent assay and intracellular cytokine staining using specific monoclonal antibodies. Synovial tissue was examined for infiltrating T cells by immunohistochemical analysis. RESULTS: We found increased numbers of circulating Th17 cells in the peripheral blood of patients with seronegative spondylarthritides (PsA and AS), but not in patients with RA or vitiligo. In addition, Th17 cells from the spondylarthritis patients showed advanced differentiation and were polyfunctional in terms of T cell receptor-driven cytokine production. CONCLUSION: These observations suggest a role of Th17 cells in the pathogenesis of certain human autoimmune disorders, in particular the seronegative spondylarthritides.

Spatial relational learning and memory abilities do not differ between men and women in a real-world, open-field environment

This study assesses gender differences in spatial and non-spatial relational learning and memory in adult humans behaving freely in a real-world, open-field environment. In Experiment 1, we tested the use of proximal landmarks as conditional cues allowing subjects to predict the location of rewards hidden in one of two sets of three distinct locations. Subjects were tested in two different conditions: (1) when local visual cues marked the potentially-rewarded locations, and (2) when no local visual cues marked the potentially-rewarded locations. We found that only 17 of 20 adults (8 males, 9 females) used the proximal landmarks to predict the locations of the rewards. Although females exhibited higher exploratory behavior at the beginning of testing, males and females discriminated the potentially-rewarded locations similarly when local visual cues were present. Interestingly, when the spatial and local information conflicted in predicting the reward locations, males considered both spatial and local information, whereas females ignored the spatial information. However, in the absence of local visual cues females discriminated the potentially-rewarded locations as well as males. In Experiment 2, subjects (9 males, 9 females) were tested with three asymmetrically-arranged rewarded locations, which were marked by local cues on alternate trials. Again, females discriminated the rewarded locations as well as males in the presence or absence of local cues. In sum, although particular aspects of task performance might differ between genders, we found no evidence that women have poorer allocentric spatial relational learning and memory abilities than men in a real-world, open-field environment.

Biomedical risk assessment as an aid for smoking cessation.

BACKGROUND: A possible strategy for increasing smoking cessation rates could be to provide smokers who have contact with healthcare systems with feedback on the biomedical or potential future effects of smoking, e.g. measurement of exhaled carbon monoxide (CO), lung function, or genetic susceptibility to lung cancer. We reviewed systematically data on smoking cessation rates from controlled trials that used biomedical risk assessment and feedback. OBJECTIVES: To determine the efficacy of biomedical risk assessment provided in addition to various levels of counselling, as a contributing aid to smoking cessation. SEARCH STRATEGY: We systematically searched he Cochrane Collaboration Tobacco Addiction Group Specialized Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (1966 to 2004), and EMBASE (1980 to 2004). We combined methodological terms with terms related to smoking cessation counselling and biomedical measurements. SELECTION CRITERIA: Inclusion criteria were: a randomized controlled trial design; subjects participating in smoking cessation interventions; interventions based on a biomedical test to increase motivation to quit; control groups receiving all other components of intervention; an outcome of smoking cessation rate at least six months after the start of the intervention. DATA COLLECTION AND ANALYSIS: Two assessors independently conducted data extraction on each paper, with disagreements resolved by consensus. MAIN RESULTS: From 4049 retrieved references, we selected 170 for full text assessment. We retained eight trials for data extraction and analysis. One of the eight used CO alone and CO + Genetic Susceptibility as two different intervention groups, giving rise to three possible comparisons. Three of the trials isolated the effect of exhaled CO on smoking cessation rates resulting in the following odds ratios (ORs) and 95% confidence intervals (95% CI): 0.73 (0.38 to 1.39), 0.93 (0.62 to 1.41), and 1.18 (0.84 to 1.64). Combining CO measurement with genetic susceptibility gave an OR of 0.58 (0.29 to 1.19). Exhaled CO measurement and spirometry were used together in three trials, resulting in the following ORs (95% CI): 0.6 (0.25 to 1.46), 2.45 (0.73 to 8.25), and 3.50 (0.88 to 13.92). Spirometry results alone were used in one other trial with an OR of 1.21 (0.60 to 2.42).Two trials used other motivational feedback measures, with an OR of 0.80 (0.39 to 1.65) for genetic susceptibility to lung cancer alone, and 3.15 (1.06 to 9.31) for ultrasonography of carotid and femoral arteries performed in light smokers (average 10 to 12 cigarettes a day). AUTHORS' CONCLUSIONS: Due to the scarcity of evidence of sufficient quality, we can make no definitive statements about the effectiveness of biomedical risk assessment as an aid for smoking cessation. Current evidence of lower quality does not however support the hypothesis that biomedical risk assessment increases smoking cessation in comparison with standard treatment. Only two studies were similar enough in term of recruitment, setting, and intervention to allow pooling of data and meta-analysis.

Verbal emotional memory in a case with left amygdala damage.

The amygdala nuclei appear to be critically implicated in emotional memory. However, in most studies, encoding and consolidation processes cannot be analyzed separately. We thus studied the verbal emotional memory in a young woman with a ganglioglioma of the left amygdala and analyzed its impact (1) on each step of the memory process (encoding, retrieval, and recognition) (2) on short- and long-term consolidation (1-hour and 1-week delay) and (3) on processing of valence (positive and negative items compared to neutral words). Results showed emotional encoding impairments and, after encoding was controlled for, emotional long-term consolidation. Finally, although the negative words were not acknowledged as emotionally arousing by the patient, these words were specifically poorly encoded, recalled, and consolidated. Our data suggest that separate cerebral networks support the processing of emotional versus neutral stimuli.

Mammalian Target of Rapamycin Complex 2 Controls CD8 T Cell Memory Differentiation in a Foxo1-Dependent Manner.

Upon infection, antigen-specific naive CD8 T cells are activated and differentiate into short-lived effector cells (SLECs) and memory precursor cells (MPECs). The underlying signaling pathways remain largely unresolved. We show that Rictor, the core component of mammalian target of rapamycin complex 2 (mTORC2), regulates SLEC and MPEC commitment. Rictor deficiency favors memory formation and increases IL-2 secretion capacity without dampening effector functions. Moreover, mTORC2-deficient memory T cells mount more potent recall responses. Enhanced memory formation in the absence of mTORC2 was associated with Eomes and Tcf-1 upregulation, repression of T-bet, enhanced mitochondrial spare respiratory capacity, and fatty acid oxidation. This transcriptional and metabolic reprogramming is mainly driven by nuclear stabilization of Foxo1. Silencing of Foxo1 reversed the increased MPEC differentiation and IL-2 production and led to an impaired recall response of Rictor KO memory T cells. Therefore, mTORC2 is a critical regulator of CD8 T cell differentiation and may be an important target for immunotherapy interventions.

Memory mixed with desire : a preliminary study of philosophy and literature in the works of Friedrich Nietzsche and Milan Kundera

Memory Mixed with Desire: A preliminary study of Philosophy and Literature in the works of Friedrich Nietzsche and Milan Kundera Robert Spinelli Brock University, Department of Philosophy This thesis studies intertextuality in the works of Friedrich Nietzsche and Milan Kundera through the primary themes of memory and forgetting. The thesis starts with two introductory chapters that delineate memory according to Nietzsche and Kundera respectively. From here, I move into a discussion of Nietzsche's Ubermensch as an example of the type of forgetting that Nietzsche sees as a cure for the overabundance of memory that has led to Christian morality. Next, I explore the Kunderan concept of kitsch as the polar opposite of what Nietzsche has sought in his philosophy, finishing the chapter by tying the two thinkers together in a Kunderan critique of Nietzsche. The thesis ends with a chapter devoted to the Eternal Return beginning with an exegesis of Nietzsche's idea and ending with a similar exegesis of Kundera's treatment of this thought. What I suggest in this chapter is that the Eternal Return might itself be a form of kitsch even in its attempt to revalue existence.

ERP and cardiovascular correlates of source memory discrimination in older and younger adults /

There is much evidence to support an age-related decline in source memory ability. However, the underlying mechanisms responsible for this decline are not well understood. The current study was carried out to determine the electrophysiological correlates of source memory discrimination in younger and older adults. Event-related potentials (ERPs) and continuous electrocardiographic (ECG) data were collected from younger (M= 21 years) and older (M= 71 years) adults during a source memory task. Older adults were more likely to make source memory errors for recently repeated, non-target words than were younger adults. Moreover, their ERP records for correct trials showed an increased amplitude in the late positive (LP) component (400-800 msec) for the most recently presented, non-target stimuli relative to the LP noted for target items. Younger adults showed an opposite pattern, with a large LP component for target items, and a much smaller LP component for the recently repeated non-target items. Computation of parasympathetic activity in the vagus nerve was performed on the ECG data (Porges, 1985). The resulting measure, vagal tone, was used as an index of physiological responsivity. The vagal tone index of physiological responsivity was negatively related to the LP amplitude for the most recently repeated, non-target words in both groups, after accounting for age effects. The ERP data support the hypothesis that the tendency to make source memory errors on the part of older adults is related to the ability to selectively control attentional processes during task performance. Furthermore, the relationship between vagal tone and ERP reactivity suggests that there is a physiological basis to the heightened reactivity measured in the LP response to recently repeated non-target items such that, under decreased physiological resources, there is an impairment in the ability to selectively inhibit bottom-up, stimulus based properties in favour of task-related goals in older adults. The inconsistency of these results with other explanatory models of source memory deficits is discussed. It is concluded that the data are consistent with a physiological reactivity model requiring inhibition of reactivity to irrelevant, but perceptually-fluent, stimuli.

Marginal/minority popular music : the concept of the "third space" and the case for "hybridities" of cultures/identities /

The topic of this thesis is marginaVminority popular music and the question of identity; the term "marginaVminority" specifically refers to members of racial and cultural minorities who are socially and politically marginalized. The thesis argument is that popular music produced by members of cultural and racial minorities establishes cultural identity and resists racist discourse. Three marginaVminority popular music artists and their songs have been chosen for analysis in support of the argument: Gil Scott-Heron's "Gun," Tracy Chapman's "Fast Car" and Robbie Robertson's "Sacrifice." The thesis will draw from two fields of study; popular music and postcolonialism. Within the area of popular music, Theodor Adorno's "Standardization" theory is the focus. Within the area of postcolonialism, this thesis concentrates on two specific topics; 1) Stuart Hall's and Homi Bhabha's overlapping perspectives that identity is a process of cultural signification, and 2) Homi Bhabha's concept of the "Third Space." For Bhabha (1995a), the Third Space defines cultures in the moment of their use, at the moment of their exchange. The idea of identities arising out of cultural struggle suggests that identity is a process as opposed to a fixed center, an enclosed totality. Cultures arise from historical memory and memory has no center. Historical memory is de-centered and thus cultures are also de-centered, they are not enclosed totalities. This is what Bhabha means by "hybridity" of culture - that cultures are not unitary totalities, they are ways of knowing and speaking about a reality that is in constant flux. In this regard, the language of "Otherness" depends on suppressing or marginalizing the productive capacity of culture in the act of enunciation. The Third Space represents a strategy of enunciation that disrupts, interrupts and dislocates the dominant discursive construction of US and THEM, (a construction explained by Hall's concept of binary oppositions, detailed in Chapter 2). Bhabha uses the term "enunciation" as a linguistic metaphor for how cultural differences are articulated through discourse and thus how differences are discursively produced. Like Hall, Bhabha views culture as a process of understanding and of signification because Bhabha sees traditional cultures' struggle against colonizing cultures as transforming them. Adorno's theory of Standardization will be understood as a theoretical position of Western authority. The thesis will argue that Adorno's theory rests on the assumption that there is an "essence" to music, an essence that Adorno rationalizes as structure/form. The thesis will demonstrate that constructing music as possessing an essence is connected to ideology and power and in this regard, Adorno's Standardization theory is a discourse of White Western power. It will be argued that "essentialism" is at the root of Western "rationalization" of music, and that the definition of what constitutes music is an extension of Western racist "discourses" of the Other. The methodological framework of the thesis entails a) applying semiotics to each of the three songs examined and b) also applying Bhabha's model of the Third Space to each of the songs. In this thesis, semiotics specifically refers to Stuart Hall's retheorized semiotics, which recognizes the dual function of semiotics in the analysis of marginal racial/cultural identities, i.e., simultaneously represent embedded racial/cultural stereotypes, and the marginal raciaVcultural first person voice that disavows and thus reinscribes stereotyped identities. (Here, and throughout this thesis, "first person voice" is used not to denote the voice of the songwriter, but rather the collective voice of a marginal racial/cultural group). This dual function fits with Hall's and Bhabha's idea that cultural identity emerges out of cultural antagonism, cultural struggle. Bhabha's Third Space is also applied to each of the songs to show that cultural "struggle" between colonizers and colonized produces cultural hybridities, musically expressed as fusions of styles/sounds. The purpose of combining semiotics and postcolonialism in the three songs to be analyzed is to show that marginal popular music, produced by members of cultural and racial minorities, establishes cultural identity and resists racist discourse by overwriting identities of racial/cultural stereotypes with identities shaped by the first person voice enunciated in the Third Space, to produce identities of cultural hybridities. Semiotic codes of embedded "Black" and "Indian" stereotypes in each song's musical and lyrical text will be read and shown to be overwritten by the semiotic codes of the first person voice, which are decoded with the aid of postcolonial concepts such as "ambivalence," "hybridity" and "enunciation."

Graffiti, memory and contested space : mnemonic initiatives following trauma and/or repression in Buenos Aires, Argentina

Graffiti, Memory and Contested Space: Mnemonic Initiatives Following Periods of Trauma and/or Repression in Buenos Aires, Argentina This thesis concerns the popular articulation ofmemory following periods or incidents of trauma in Argentina. I am interested in how groups lay claim to various public spaces in the city and how they convert these spaces into mnemonic battlegrounds. In considering these spaces of trauma and places of memory, I am primarily interested in how graffiti writing (stencils, spray-paint, signatures, etchings, wall-paintings, murals and installations) is used to make these spaces transmit particular memories that impugn official versions of the past. This thesis draws on literatures focused on popular/public memory. Scholars argue that memory is socially constructed and thus actively contested. Marginal initiatives such as graffiti writing challenge the memory projects of the state as well as state projects that are perceived by citizens to be 'inadequate,' 'inappropriate,' and/or as promoting the erasure of memory. Many of these initiatives are a reaction to the proreconciliation and pro-oblivion strategies of previous governments. I outline that the history of silences and impunity, and a longstanding emphasis on reconciliation at the expense of truth and justice has created an environment of vulnerable memory in Argentina. Popular memory entrepreneurs react by aggressively articulating their memories in time and in space. As a result of this intense memory work, the built landscape in Buenos Aires is dotted with mnemonic initiatives that aim to contradict or subvert officially sanctioned memories. I also suggest that memory workers in Argentina persistently and carefially use the sites of trauma as well as key public spaces to ensure official as well as popular audiences . The data for this project was collected in five spaces in Buenos Aires, the Plaza de Mayo, Plaza Congreso, La Republica Cromanon nightclub, Avellaneda Train Station and El Olimpo, a former detention centre from the military dictatorship.