An Exact Method for Analysis of Value-based Array Data Dependences

Standard array data dependence testing algorithms give information about the aliasing of array references. If statement 1 writes a[5], and statement 2 later reads a[5], standard techniques described this as a flow dependence, even if there was an intervening write. We call a dependence between two references to the same memory location a memory-based dependence. In contrast, if there are no intervening writes, the references touch the same value and we call the dependence a value-based dependence. There has been a surge of recent work on value-based array data dependence analysis (also referred to as computation of array data-flow dependence information). In this paper, we describe a technique that is exact over programs without control flow (other than loops) and non-linear references. We compare our proposal with the technique proposed by Paul Feautrier, which is the other technique that is complete over the same domain as ours. We also compare our work with that of Tu and Padua, a representative approximate scheme for array privatization. (Also cross-referenced as UMIACS-TR-93-137

Nonlinear Array Dependence Analysis

Standard array data dependence techniques can only reason about linear constraints. There has also been work on analyzing some dependences involving polynomial constraints. Analyzing array data dependences in real-world programs requires handling many ``unanalyzable'' terms: subscript arrays, run-time tests, function calls. The standard approach to analyzing such programs has been to omit and ignore any constraints that cannot be reasoned about. This is unsound when reasoning about value-based dependences and whether privatization is legal. Also, this prevents us from determining the conditions that must be true to disprove the dependence. These conditions could be checked by a run-time test or verified by a programmer or aggressive, demand-driven interprocedural analysis. We describe a solution to these problems. Our solution makes our system sound and more accurate for analyzing value-based dependences and derives conditions that can be used to disprove dependences. We also give some preliminary results from applying our techniques to programs from the Perfect benchmark suite. (Also cross-referenced as UMIACS-TR-94-123

Static Analysis of Upper and Lower Bounds on Dependences and Parallelism

Existing compilers often fail to parallelize sequential code, even when a program can be manually transformed into parallel form by a sequence of well-understood transformations (as is the case for many of the Perfect Club Benchmark programs). These failures can occur for several reasons: the code transformations implemented in the compiler may not be sufficient to produce parallel code, the compiler may not find the proper sequence of transformations, or the compiler may not be able to prove that one of the necessary transformations is legal. When a compiler extract sufficient parallelism from a program, the programmer extract additional parallelism. Unfortunately, the programmer is typically left to search for parallelism without significant assistance. The compiler generally does not give feedback about which parts of the program might contain additional parallelism, or about the types of transformations that might be needed to realize this parallelism. Standard program transformations and dependence abstractions cannot be used to provide this feedback. In this paper, we propose a two step approach for the search for parallelism in sequential programs: We first construct several sets of constraints that describe, for each statement, which iterations of that statement can be executed concurrently. By constructing constraints that correspond to different assumptions about which dependences might be eliminated through additional analysis, transformations and user assertions, we can determine whether we can expose parallelism by eliminating dependences. In the second step of our search for parallelism, we examine these constraint sets to identify the kinds of transformations that are needed to exploit scalable parallelism. Our tests will identify conditional parallelism and parallelism that can be exposed by combinations of transformations that reorder the iteration space (such as loop interchange and loop peeling). This approach lets us distinguish inherently sequential code from code that contains unexploited parallelism. It also produces information about the kinds of transformations that will be needed to parallelize the code, without worrying about the order of application of the transformations. Furthermore, when our dependence test is inexact, we can identify which unresolved dependences inhibit parallelism by comparing the effects of assuming dependence or independence. We are currently exploring the use of this information in programmer-assisted parallelization. (Also cross-referenced as UMIACS-TR-94-40

A new synthesis and preliminary evaluation of some analogues of mecamylamine – a compound with anti-addiction properties

A new synthesis of mecamylamine – a known anti-hypertensive drug with anti-addictive properties is described. The new route allowed access to two novel analogues whose activity at two nicotinic acetylcholine receptor subtypes was assessed

Sampling molecular conformations and dynamics in a multiuser virtual reality framework

Copyright © 2018 The Authors, some rights reserved. We describe a framework for interactive molecular dynamics in a multiuser virtual reality (VR) environment, combining rigorous cloud-mounted atomistic physics simulations with commodity VR hardware, which we have made accessible to readers (see isci.itch.io/nsb-imd). It allows users to visualize and sample, with atomic-level precision, the structures and dynamics of complex molecular structures “on the fly” and to interact with other users in the same virtual environment. A series of controlled studies, in which participants were tasked with a range of molecular manipulation goals (threading methane through a nanotube, changing helical screw sense, and tying a protein knot), quantitatively demonstrate that users within the interactive VR environment can complete sophisticated molecular modeling tasks more quickly than they can using conventional interfaces, especially for molecular pathways and structural transitions whose conformational choreographies are intrinsically three-dimensional. This framework should accelerate progress in nanoscale molecular engineering areas including conformational mapping, drug development, synthetic biology, and catalyst design. More broadly, our findings highlight the potential of VR in scientific domains where three-dimensional dynamics matter, spanning research and education

Protracted treatment with MDMA induces heteromeric nicotinic receptor up-regulation in rat brain: an autoradiography study.

Previous studies indicate that 3,4-methylenedioxy-methamphetamine (MDMA, ecstasy) can induce heteromeric nicotinic acetylcholine receptor (nAChR, mainly of α4β2 subtype) up-regulation. In this study we treated Sprague-Dawley rats twice-daily for 10 days with either saline or MDMA (7 mg/kg) and killed them on day 11 to perform [125I]epibatidine binding autoradiograms on serial coronal slices. Results showed significant increases in nAChR density in the substantia nigra, ventral tegmental area, nucleus accumbens, olfactory tubercle, anterior caudate-putamen, somatosensory cortex, motor cortex, auditory cortex, retrosplenial cortex, laterodorsal thalamus nuclei, amygdala, postsubiculum and pontine nuclei. These increases ranged from 3% (retrosplenial cortex) to 30 and 33% (amygdala and substantia nigra). No increased α4 subunit immunoreactivity was found in up-regulated areas compared with saline-treated rats, suggesting a post-translational mechanism as occurs with nicotine. The percentage of up-regulation correlated positively with the density of serotonin transporters, according to the serotonergic profile of MDMA. The heteromeric nAChR increase in concrete areas could account, at least in part, for the reinforcing, sensitizing and psychiatric disorders observed after long-term treatment with MDMA

UK Kidney association clinical practice guideline: sodium-glucose co-transporter-2 (SGLT-2) inhibition in adults with kidney disease 2023 UPDATE

Large placebo-controlled trials have demonstrated kidney and cardiovascular clinical benefits of SGLT-2 inhibitors. Data from the EMPA-KIDNEY and DELIVER trials and associated meta-analyses triggered an update to the UK Kidney Association Clinical Practice Guideline on Sodium-Glucose Co-transporter-2 (SGLT-2) Inhibition in Adults with Kidney Disease. We provide a summary of the full guideline and highlight the rationale for recent updates. The use of SGLT-2 inhibitors in people with specific medical conditions, including type 1 diabetes, kidney transplants, and people admitted to hospital with heart failure is also considered, along with Recommendations for future research and Recommendations for implementation. A full “lay” summary of the guidelines is provided as an appendix to ensure that these guidelines are accessible and understandable to people who are not medical professionals