Inefficiencies in the Cache Hierarchy: A Sensitivity Study of Cacheline Size with Mobile Workloads

With the rising number of cores in mobile devices, the cache hierarchy in mobile application processors gets deeper, and the cache size gets bigger. However, the cacheline size remained relatively constant over the last decade in mobile application processors. In this work, we investigate whether the cacheline size in mobile application processors is due for a refresh, by looking at inefficiencies in the cache hierarchy which tend to be exacerbated when increasing the cacheline size: false sharing and cacheline utilization. Firstly, we look at false sharing, which is more likely to arise at larger cacheline sizes and can severely impact performance. False sharing occurs when non-shared data structures, mapped onto the same cacheline, are being accessed by threads running on different cores, causing avoidable invalidations and subsequent misses. False sharing has been found in various places such as scientific workloads and real applications. We find that whilst increasing the cacheline size does increase false sharing, it still is negligible when compared to known cases of false sharing in scientific workloads, due to the limited level of thread-level parallelism in mobile workloads. Secondly, we look at cacheline utilization which measures the number of bytes in a cacheline actually used by the processor. This effect has been investigated under various names for a multitude of server and desktop applications. As a low cacheline utilization implies that very little of the fetched cachelines was used by the processor, this causes waste in bandwidth and energy in moving data across the memory hierarchy. The energy cost associated with data movements is much higher compared to logic operations, increasing the need for cache efficiency, especially in the case of an energy-constrained platform like a mobile device. We find that the cacheline utilization of mobile workloads is low in general, decreasing when increasing the cacheline size. When increasing the cacheline size from 64 bytes to 128 bytes, the number of misses will be reduced by 10%-30%, depending on the workload. However, because of the low cacheline utilization, this more than doubles the amount of unused traffic to the L1 caches. Using the cacheline utilization as a metric in this way, illustrates an important point. If a change in cacheline size would only be assessed on its local effects, we find that this change in cacheline size will only have advantages as the miss rate decreases. However, at system level, this change will increase the stress on the bus and increase the amount of wasted energy due to unused traffic. Using cacheline utilization as a metric underscores the need for system-level research when changing characteristics of the cache hierarchy

Strong interaction of a turbulent spot with a shock-induced separation bubble

Direct numerical simulations have been conducted to study the passage of a turbulent spot through a shock-induced separation bubble. Localized blowing is used to trip the boundary layer well upstream of the shock impingement, leading to mature turbulent spots at impingement, with a length comparable to the length of the separation zone. Interactions are simulated at free stream Mach numbers of two and four, for isothermal (hot) wall boundary conditions. The core of the spot is seen to tunnel through the separation bubble, leading to a transient reattachment of the flow. Recovery times are long due to the influence of the calmed region behind the spot. The propagation speed of the trailing interface of the spot decreases during the interaction and a substantial increase in the lateral spreading of the spot was observed. A conceptual model based on the growth of the lateral shear layer near the wingtips of the spot is used to explain the change in lateral growth rat

Annotation and analysis of a large cuticular protein family with the R&R Consensus in Anopheles gambiae

<p>Abstract</p> <p>Background</p> <p>The most abundant family of insect cuticular proteins, the CPR family, is recognized by the R&R Consensus, a domain of about 64 amino acids that binds to chitin and is present throughout arthropods. Several species have now been shown to have more than 100 CPR genes, inviting speculation as to the functional importance of this large number and diversity.</p> <p>Results</p> <p>We have identified 156 genes in <it>Anopheles gambiae </it>that code for putative cuticular proteins in this CPR family, over 1% of the total number of predicted genes in this species. Annotation was verified using several criteria including identification of TATA boxes, INRs, and DPEs plus support from proteomic and gene expression analyses. Two previously recognized CPR classes, RR-1 and RR-2, form separate, well-supported clades with the exception of a small set of genes with long branches whose relationships are poorly resolved. Several of these outliers have clear orthologs in other species. Although both clades are under purifying selection, the RR-1 variant of the R&R Consensus is evolving at twice the rate of the RR-2 variant and is structurally more labile. In contrast, the regions flanking the R&R Consensus have diversified in amino-acid composition to a much greater extent in RR-2 genes compared with RR-1 genes. Many genes are found in compact tandem arrays that may include similar or dissimilar genes but always include just one of the two classes. Tandem arrays of RR-2 genes frequently contain subsets of genes coding for highly similar proteins (sequence clusters). Properties of the proteins indicated that each cluster may serve a distinct function in the cuticle.</p> <p>Conclusion</p> <p>The complete annotation of this large gene family provides insight on the mechanisms of gene family evolution and clues about the need for so many CPR genes. These data also should assist annotation of other <it>Anopheles </it>genes.</p

Patient Follow-Up After Participating in a Beach-Based Skin Cancer Screening Program

Many skin cancer screenings occur in non-traditional community settings, with the beach being an important setting due to beachgoers being at high risk for skin cancer. This study is a secondary analysis of data from a randomized trial of a skin cancer intervention in which participants (n = 312) had a full-body skin examination by a clinician and received a presumptive diagnosis (abnormal finding, no abnormal finding). Participants’ pursuit of follow-up was assessed post-intervention (n = 283). Analyses examined: (1) participant’s recall of screening results; and (2) whether cognitive and behavioral variables were associated with follow-up being as advised. Just 12% of participants (36/312) did not correctly recall the results of their skin examination. One-third (33%, 93/283) of participants’ follow-up was classified as being not as advised (recommend follow-up not pursued, unadvised follow-up pursued). Among participants whose follow-up was not as advised, 71% (66/93) did not seek recommended care. None of the measured behavioral and cognitive variables were significantly associated with recall of screening examination results or whether follow-up was as advised. Research is needed to determine what factors are associated with follow-up being as advised and to develop messages that increase receipt of advised follow-up care

Power-Based Droop Control in DC Microgrids Enabling Seamless Disconnection From Upstream Grids

This paper proposes a local power-based droop controller for distributed energy resource converters in dc microgrids that are connected to upstream grids by grid-interface converters. During normal operation, the grid-interface converter imposes the microgrid bus voltage, and the proposed controller allows power flow regulation at distributed energy resource converters\u2019 output. On the other hand, during abnormal operation of the grid-interface converter (e.g., due to faults in the upstream grid), the proposed controller allows bus voltage regulation by droop control. Notably, the controller can autonomously convert from power flow control to droop control, without any need of bus voltage variation detection schemes or communication with other microgrid components, which enables seamless transitions between these two modes of operation. Considering distributed energy resource converters employing the power-based droop control, the operation modes of a single converter and of the whole microgrid are defined and investigated herein. The controller design is also introduced. Furthermore, the power sharing performance of this control approach is analyzed and compared with that of classical droop control. The experimental results from a laboratory-scale dc microgrid prototype are reported to show the final performances of the proposed power-based droop control

Cognitive conflicts in major depression : Between desired change and personal coherence

This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposesThe notion of intrapsychic conflict has been present in psychopathology for more than a century within different theoretical orientations. However, internal conflicts have not received enough empirical attention, nor has their importance in depression been fully elaborated. This study is based on the notion of cognitive conflict, understood as implicative dilemma (ID), and on a new way of identifying these conflicts by means of the Repertory Grid Technique. Our aim was to explore the relevance of cognitive conflicts among depressive patientsPeer reviewedFinal Published versio

K-shell photoionization of ground-state Li-like carbon ions [C3+^{3+}]: experiment, theory and comparison with time-reversed photorecombination

Absolute cross sections for the K-shell photoionization of ground-state Li-like carbon [C$^{3+}$(1s$^2$2s $^2$S)] ions were measured by employing the ion-photon merged-beams technique at the Advanced Light Source. The energy ranges 299.8--300.15 eV, 303.29--303.58 eV and 335.61--337.57 eV of the [1s(2s2p)$^3$P]$^2$P, [1s(2s2p)$^1$P]$^2$P and [(1s2s)$^3$S 3p]$^2$P resonances, respectively, were investigated using resolving powers of up to 6000. The autoionization linewidth of the [1s(2s2p)$^1$P]$^2$P resonance was measured to be $27 \pm 5$ meV and compares favourably with a theoretical result of 26 meV obtained from the intermediate coupling R-Matrix method. The present photoionization cross section results are compared with the outcome from photorecombination measurements by employing the principle of detailed balance.Comment: 3 figures and 2 table

Libri novi

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43275/1/11046_2005_Article_BF02089133.pd

Social determinants of health and cancer screening implementation and outcomes in the USA: A systematic review protocol

BACKGROUND: Improving the delivery, uptake, and implementation of cancer screening to meet evidence-based recommendations is needed to reduce persistent cancer health disparities in the USA. Current national public health targets emphasize the role of social determinants of health (SDOH) on cancer screening. However, there remains a need to explicate these linkages, toward the goal of identifying and implementing effective interventions that target and address SDOH to reduce inequities in cancer screening. METHODS: We will conduct a systematic review of English language peer-reviewed original research articles published between 2010 and 2021 that describe observational (qualitative and quantitative) and intervention studies conducted in the USA. In alignment with Healthy People 2030, we will include studies of breast, cervical, colorectal, and/or lung cancer screening. Guided by multiple SDOH frameworks, we will broadly define SDOH by five domain areas: economic stability, education access and quality, healthcare access and quality, neighborhood and built environment, and social and community context. Following systematic literature searches in five databases (Ovid MEDLINE, Embase, CINAHL, Web of Science, Cochrane Library) and piloting of screening procedures, reviewers will independently screen titles/abstracts for potential relevance. Reviewer pairs will then screen full text articles for eligibility criteria. We will extract data items from included articles, including study characteristics, cancer screening intervention information, and coding of SDOH constructs. We will assess study quality using the Mixed Methods Appraisal Tool and synthesize our findings using narrative, descriptive statistics, tables, and figures. Our approach will adhere to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) recommendations. DISCUSSION: By completing this systematic review, we will summarize recent literature on SDOH and cancer screening, identify research gaps for inclusion of SDOH, and propose future opportunities for advancing equity in cancer screening by integrating SDOH as part of the implementation context to promote uptake, sustainability, and scale-up in the implementation of screening guidelines. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42021276582

The medical student

The Medical Student was published from 1888-1921 by the students of Boston University School of Medicine