An anisotropic viscoplasticity model for shale based on layered microstructure homogenization

Viscoplastic deformation of shale is frequently observed in many subsurface applications. Many studies have suggested that this viscoplastic behavior is anisotropic---specifically, transversely isotropic---and closely linked to the layered composite structure at the microscale. In this work, we develop a two-scale constitutive model for shale in which anisotropic viscoplastic behavior naturally emerges from semi-analytical homogenization of a bi-layer microstructure. The microstructure is modeled as a composite of soft layers, representing a ductile matrix formed by clay and organics, and hard layers, corresponding to a brittle matrix composed of stiff minerals. This layered microstructure renders the macroscopic behavior anisotropic, even when the individual layers are modeled with isotropic constitutive laws. Using a common correlation between clay and organic content and magnitude of creep, we apply a viscoplastic Modified Cam-Clay plasticity model to the soft layers, while treating the hard layers as a linear elastic material to minimize the number of calibration parameters. We then describe the implementation of the proposed model in a standard material update subroutine. The model is validated with laboratory creep data on samples from three gas shale formations. We also demonstrate the computational behavior of the proposed model through simulation of time-dependent borehole closure in a shale formation with different bedding plane directions

Mechanical and Deformation Properties of Rubberized Engineered Cementitious Composites (ECC) Containing 3D-Printed Origami Hollow Bodies

Bubble concrete is a lightweight concrete achieved by mixing high-strength hollow bodies into concrete. Bubble concrete is different from the biaxial voided slabs as it can reduce the density of concrete while ensuring the strength. The hollow bodies used not only to create multiple cavities, but also to transfer internal stresses

Cerebral blood flow and immediate and sustained executive function benefits following single bouts of passive and active exercise

Passive exercise occurs when an individual's limbs are moved via an external force and is a modality that increases cerebral blood flow (CBF) and provides an immediate postexercise executive function (EF) benefit. To our knowledge, no work has examined for how long passive exercise benefits EF. Here, healthy young adults (N = 22; 7 female) used a cycle ergometer to complete three 20-min conditions: passive exercise (via mechanically driven flywheel), a traditional light intensity (37 W) "active" exercise condition (i.e., via volitional pedalling) and a non-exercise control condition. An estimate of CBF was obtained via transcranial Doppler ultrasound measurement of middle cerebral artery blood velocity (MCAv) and antisaccades (i.e., saccade mirror-symmetrical to a target) were completed prior to and immediately, 30- and 60-min following each condition to assess EF. Passive and active exercise increased MCAv; however, the increase was larger in the latter condition. In terms of antisaccades, passive and active exercise provided an immediate postexercise reaction time benefit. At the 30-min assessment, the benefit was observed for active but not passive exercise and neither produced a benefit at the 60-min assessment. Thus, passive exercise provided an evanescent EF "boost" and is a finding that may reflect a smaller cortical hemodynamic response

Riverine sustainment 2012

Student Integrated ProjectIncludes supplementary materialThis technical report analyzed the Navy's proposed Riverine Force (RF) structure and capabilities for 2012. The Riverine Sustainment 2012 Team (RST) examined the cost and performance of systems of systems which increased RF sustainment in logistically barren environments. RF sustainment was decomposed into its functional areas of supply, repair, and force protection. The functional and physical architectures were developed in parallel and were used to construct an operational architecture for the RF. The RST used mathematical, agent-based and queuing models to analyze various supply, repair and force protection system alternatives. Extraction of modeling data revealed several key insights. Waterborne heavy lift connectors such as the LCU-2000 are vital in the re-supply of the RF when it is operating up river in a non-permissive environment. Airborne heavy lift connectors such as the MV-22 were ineffective and dominated by the waterborne variants in the same environment. Increase in manpower and facilities did appreciable add to the operational availability of the RF. Mean supply response time was the biggest factor effecting operational availability and should be kept below 24 hours to maintain operational availability rates above 80%. Current mortar defenses proposed by the RF are insufficient.N

Resisting Sleep Pressure:Impact on Resting State Functional Network Connectivity

In today's 24/7 society, sleep restriction is a common phenomenon which leads to increased levels of sleep pressure in daily life. However, the magnitude and extent of impairment of brain functioning due to increased sleep pressure is still not completely understood. Resting state network (RSN) analyses have become increasingly popular because they allow us to investigate brain activity patterns in the absence of a specific task and to identify changes under different levels of vigilance (e.g. due to increased sleep pressure). RSNs are commonly derived from BOLD fMRI signals but studies progressively also employ cerebral blood flow (CBF) signals. To investigate the impact of sleep pressure on RSNs, we examined RSNs of participants under high (19 h awake) and normal (10 h awake) sleep pressure with three imaging modalities (arterial spin labeling, BOLD, pseudo BOLD) while providing confirmation of vigilance states in most conditions. We demonstrated that CBF and pseudo BOLD signals (measured with arterial spin labeling) are suited to derive independent component analysis based RSNs. The spatial map differences of these RSNs were rather small, suggesting a strong biological substrate underlying these networks. Interestingly, increased sleep pressure, namely longer time awake, specifically changed the functional network connectivity (FNC) between RSNs. In summary, all FNCs of the default mode network with any other network or component showed increasing effects as a function of increased 'time awake'. All other FNCs became more anti-correlated with increased 'time awake'. The sensorimotor networks were the only ones who showed a within network change of FNC, namely decreased connectivity as function of 'time awake'. These specific changes of FNC could reflect both compensatory mechanisms aiming to fight sleep as well as a first reduction of consciousness while becoming drowsy. We think that the specific changes observed in functional network connectivity could imply an impairment of information transfer between the affected RSNs

Physical rehabilitation approaches for the recovery of function and mobility following stroke

Background: Various approaches to physical rehabilitation to improve function and mobility are used after stroke. There is considerable controversy around the relative effectiveness of approaches, and little known about optimal delivery and dose. Some physiotherapists base their treatments on a single approach; others use components from several different approaches. Objectives: Primary objective: To determine whether physical rehabilitation is effective for recovery of function and mobility in people with stroke, and to assess if any one physical rehabilitation approach is more effective than any other approach. Secondary objective: To explore factors that may impact the effectiveness of physical rehabilitation approaches, including time after stroke, geographical location of study, intervention dose/duration, intervention provider, and treatment components. Stakeholder involvement: Key aims were to clarify the focus of the review, inform decisions about subgroup analyses, and co-produce statements relating to key implications. Search methods: For this update, we searched the Cochrane Stroke Trials Register (last searched November 2022), CENTRAL (2022, Issue 10), MEDLINE (1966 to November 2022), Embase (1980 to November 2022), AMED (1985 to November 2022), CINAHL (1982 to November 2022), and the Chinese Biomedical Literature Database (to November 2022). Selection criteria: Inclusion criteria: Randomised controlled trials (RCTs) of physical rehabilitation approaches aimed at promoting the recovery of function or mobility in adult participants with a clinical diagnosis of stroke. Exclusion criteria: RCTs of upper limb function or single treatment components. Primary outcomes: measures of independence in activities of daily living (IADL) and motor function. Secondary outcomes: balance, gait velocity, and length of stay. Data collection and analysis: Two independent authors selected studies according to pre-defined eligibility criteria, extracted data, and assessed the risk of bias in the included studies. We used GRADE to assess the certainty of evidence. Main results: In this review update, we included 267 studies (21,838 participants). Studies were conducted in 36 countries, with half (133/267) in China. Generally, studies were heterogeneous, and often poorly reported. We judged only 14 studies in meta-analyses as at low risk of bias for all domains and, on average, we considered 33% of studies in analyses of primary outcomes at high risk of bias. Is physical rehabilitation more effective than no (or minimal) physical rehabilitation?. Compared to no physical rehabilitation, physical rehabilitation may improve IADL (standardised mean difference (SMD) 1.32, 95% confidence interval (CI) 1.08 to 1.56; 52 studies, 5403 participants; low-certainty evidence) and motor function (SMD 1.01, 95% CI 0.80 to 1.22; 50 studies, 5669 participants; low-certainty evidence). There was evidence of long-term benefits for these outcomes. Physical rehabilitation may improve balance (MD 4.54, 95% CI 1.36 to 7.72; 9 studies, 452 participants; low-certainty evidence) and likely improves gait velocity (SMD 0.23, 95% CI 0.05 to 0.42; 18 studies, 1131 participants; moderate-certainty evidence), but with no evidence of long-term benefits. Is physical rehabilitation more effective than attention control?. The evidence is very uncertain about the effects of physical rehabilitation, as compared to attention control, on IADL (SMD 0.91, 95% CI 0.06 to 1.75; 2 studies, 106 participants), motor function (SMD 0.13, 95% CI -0.13 to 0.38; 5 studies, 237 participants), and balance (MD 6.61, 95% CI -0.45 to 13.66; 4 studies, 240 participants). Physical rehabilitation likely improves gait speed when compared to attention control (SMD 0.34, 95% CI 0.14 to 0.54; 7 studies, 405 participants; moderate-certainty evidence). Does additional physical rehabilitation improve outcomes?. Additional physical rehabilitation may improve IADL (SMD 1.26, 95% CI 0.82 to 1.71; 21 studies, 1972 participants; low-certainty evidence) and motor function (SMD 0.69, 95% CI 0.46 to 0.92; 22 studies, 1965 participants; low-certainty evidence). Very few studies assessed these outcomes at long-term follow-up. Additional physical rehabilitation may improve balance (MD 5.74, 95% CI 3.78 to 7.71; 15 studies, 795 participants; low-certainty evidence) and gait velocity (SMD 0.59, 95% CI 0.26 to 0.91; 19 studies, 1004 participants; low-certainty evidence). Very few studies assessed these outcomes at long-term follow-up. Is any one approach to physical rehabilitation more effective than any other approach?. Compared to other approaches, those that focus on functional task training may improve IADL (SMD 0.58, 95% CI 0.29 to 0.87; 22 studies, 1535 participants; low-certainty evidence) and motor function (SMD 0.72, 95% CI 0.21 to 1.22; 20 studies, 1671 participants; very low-certainty evidence) but the evidence in the latter is very uncertain. The benefit was sustained long-term. The evidence is very uncertain about the effect of functional task training on balance (MD 2.16, 95% CI -0.24 to 4.55) and gait velocity (SMD 0.28, 95% CI -0.01 to 0.56). Compared to other approaches, neurophysiological approaches may be less effective than other approaches in improving IADL (SMD -0.34, 95% CI -0.63 to -0.06; 14 studies, 737 participants; low-certainty evidence), and there may be no difference in improving motor function (SMD -0.60, 95% CI -1.32 to 0.12; 13 studies, 663 participants; low-certainty evidence), balance (MD -0.60, 95% CI -5.90 to 6.03; 9 studies, 292 participants; low-certainty evidence), and gait velocity (SMD -0.17, 95% CI -0.62 to 0.27; 16 studies, 630 participants; very low-certainty evidence), but the evidence is very uncertain about the effect on gait velocity. For all comparisons, the evidence is very uncertain about the effects of physical rehabilitation on adverse events and length of hospital stay. Authors' conclusions: Physical rehabilitation, using a mix of different treatment components, likely improves recovery of function and mobility after stroke. Additional physical rehabilitation, delivered as an adjunct to 'usual' rehabilitation, may provide added benefits. Physical rehabilitation approaches that focus on functional task training may be useful. Neurophysiological approaches to physical rehabilitation may be no different from, or less effective than, other physical rehabilitation approaches. Certainty in this evidence is limited due to substantial heterogeneity, with mainly small studies and important differences between study populations and interventions. We feel it is unlikely that any studies published since November 2022 would alter our conclusions. Given the size of this review, future updates warrant consensus discussion amongst stakeholders to ensure the most relevant questions are explored for optimal decision-making.</p

Physical rehabilitation approaches for the recovery of function and mobility following stroke

Gill Baer - ORCID: 0000-0002-1528-2851 https://orcid.org/0000-0002-1528-2851Background Various approaches to physical rehabilitation to improve function and mobility are used after stroke. There is considerable controversy around the relative effectiveness of approaches, and little known about optimal delivery and dose. Some physiotherapists base their treatments on a single approach; others use components from several different approaches. Objectives Primary objective: To determine whether physical rehabilitation is effective for recovery of function and mobility in people with stroke, and to assess if any one physical rehabilitation approach is more effective than any other approach. Secondary objective: To explore factors that may impact the effectiveness of physical rehabilitation approaches, including time after stroke, geographical location of study, intervention dose/duration, intervention provider, and treatment components. Stakeholder involvement: Key aims were to clarify the focus of the review, inform decisions about subgroup analyses, and co‐produce statements relating to key implications. Search methods For this update, we searched the Cochrane Stroke Trials Register (last searched November 2022), CENTRAL (2022, Issue 10), MEDLINE (1966 to November 2022), Embase (1980 to November 2022), AMED (1985 to November 2022), CINAHL (1982 to November 2022), and the Chinese Biomedical Literature Database (to November 2022). Selection criteria Inclusion criteria: Randomised controlled trials (RCTs) of physical rehabilitation approaches aimed at promoting the recovery of function or mobility in adult participants with a clinical diagnosis of stroke. Exclusion criteria: RCTs of upper limb function or single treatment components. Primary outcomes: measures of independence in activities of daily living (IADL) and motor function. Secondary outcomes: balance, gait velocity, and length of stay. Data collection and analysis Two independent authors selected studies according to pre‐defined eligibility criteria, extracted data, and assessed the risk of bias in the included studies. We used GRADE to assess the certainty of evidence. Main results In this review update, we included 267 studies (21,838 participants). Studies were conducted in 36 countries, with half (133/267) in China. Generally, studies were heterogeneous, and often poorly reported. We judged only 14 studies in meta‐analyses as at low risk of bias for all domains and, on average, we considered 33% of studies in analyses of primary outcomes at high risk of bias. Is physical rehabilitation more effective than no (or minimal) physical rehabilitation? Compared to no physical rehabilitation, physical rehabilitation may improve IADL (standardised mean difference (SMD) 1.32, 95% confidence interval (CI) 1.08 to 1.56; 52 studies, 5403 participants; low‐certainty evidence) and motor function (SMD 1.01, 95% CI 0.80 to 1.22; 50 studies, 5669 participants; low‐certainty evidence). There was evidence of long‐term benefits for these outcomes. Physical rehabilitation may improve balance (MD 4.54, 95% CI 1.36 to 7.72; 9 studies, 452 participants; low‐certainty evidence) and likely improves gait velocity (SMD 0.23, 95% CI 0.05 to 0.42; 18 studies, 1131 participants; moderate‐certainty evidence), but with no evidence of long‐term benefits. Is physical rehabilitation more effective than attention control? The evidence is very uncertain about the effects of physical rehabilitation, as compared to attention control, on IADL (SMD 0.91, 95% CI 0.06 to 1.75; 2 studies, 106 participants), motor function (SMD 0.13, 95% CI ‐0.13 to 0.38; 5 studies, 237 participants), and balance (MD 6.61, 95% CI ‐0.45 to 13.66; 4 studies, 240 participants). Physical rehabilitation likely improves gait speed when compared to attention control (SMD 0.34, 95% CI 0.14 to 0.54; 7 studies, 405 participants; moderate‐certainty evidence). Does additional physical rehabilitation improve outcomes? Additional physical rehabilitation may improve IADL (SMD 1.26, 95% CI 0.82 to 1.71; 21 studies, 1972 participants; low‐certainty evidence) and motor function (SMD 0.69, 95% CI 0.46 to 0.92; 22 studies, 1965 participants; low‐certainty evidence). Very few studies assessed these outcomes at long‐term follow‐up. Additional physical rehabilitation may improve balance (MD 5.74, 95% CI 3.78 to 7.71; 15 studies, 795 participants; low‐certainty evidence) and gait velocity (SMD 0.59, 95% CI 0.26 to 0.91; 19 studies, 1004 participants; low‐certainty evidence). Very few studies assessed these outcomes at long‐term follow‐up. Is any one approach to physical rehabilitation more effective than any other approach? Compared to other approaches, those that focus on functional task training may improve IADL (SMD 0.58, 95% CI 0.29 to 0.87; 22 studies, 1535 participants; low‐certainty evidence) and motor function (SMD 0.72, 95% CI 0.21 to 1.22; 20 studies, 1671 participants; very low‐certainty evidence) but the evidence in the latter is very uncertain. The benefit was sustained long‐term. The evidence is very uncertain about the effect of functional task training on balance (MD 2.16, 95% CI ‐0.24 to 4.55) and gait velocity (SMD 0.28, 95% CI ‐0.01 to 0.56). Compared to other approaches, neurophysiological approaches may be less effective than other approaches in improving IADL (SMD ‐0.34, 95% CI ‐0.63 to ‐0.06; 14 studies, 737 participants; low‐certainty evidence), and there may be no difference in improving motor function (SMD ‐0.60, 95% CI ‐1.32 to 0.12; 13 studies, 663 participants; low‐certainty evidence), balance (MD ‐0.60, 95% CI ‐5.90 to 6.03; 9 studies, 292 participants; low‐certainty evidence), and gait velocity (SMD ‐0.17, 95% CI ‐0.62 to 0.27; 16 studies, 630 participants; very low‐certainty evidence), but the evidence is very uncertain about the effect on gait velocity. For all comparisons, the evidence is very uncertain about the effects of physical rehabilitation on adverse events and length of hospital stay. Authors' conclusions Physical rehabilitation, using a mix of different treatment components, likely improves recovery of function and mobility after stroke. Additional physical rehabilitation, delivered as an adjunct to 'usual' rehabilitation, may provide added benefits. Physical rehabilitation approaches that focus on functional task training may be useful. Neurophysiological approaches to physical rehabilitation may be no different from, or less effective than, other physical rehabilitation approaches. Certainty in this evidence is limited due to substantial heterogeneity, with mainly small studies and important differences between study populations and interventions. We feel it is unlikely that any studies published since November 2022 would alter our conclusions. Given the size of this review, future updates warrant consensus discussion amongst stakeholders to ensure the most relevant questions are explored for optimal decision‐making.https://doi.org/10.1002/14651858.CD001920.pub4pubpub

CodeGemma: Open Code Models Based on Gemma

This paper introduces CodeGemma, a collection of specialized open code models built on top of Gemma, capable of a variety of code and natural language generation tasks. We release three model variants. CodeGemma 7B pretrained (PT) and instruction-tuned (IT) variants have remarkably resilient natural language understanding, excel in mathematical reasoning, and match code capabilities of other open models. CodeGemma 2B is a state-of-the-art code completion model designed for fast code infilling and open-ended generation in latency-sensitive settings.Comment: v1: 11 pages, 4 figures, 5 tables. v2: Update metadat

PaLM 2 Technical Report

We introduce PaLM 2, a new state-of-the-art language model that has better multilingual and reasoning capabilities and is more compute-efficient than its predecessor PaLM. PaLM 2 is a Transformer-based model trained using a mixture of objectives. Through extensive evaluations on English and multilingual language, and reasoning tasks, we demonstrate that PaLM 2 has significantly improved quality on downstream tasks across different model sizes, while simultaneously exhibiting faster and more efficient inference compared to PaLM. This improved efficiency enables broader deployment while also allowing the model to respond faster, for a more natural pace of interaction. PaLM 2 demonstrates robust reasoning capabilities exemplified by large improvements over PaLM on BIG-Bench and other reasoning tasks. PaLM 2 exhibits stable performance on a suite of responsible AI evaluations, and enables inference-time control over toxicity without additional overhead or impact on other capabilities. Overall, PaLM 2 achieves state-of-the-art performance across a diverse set of tasks and capabilities. When discussing the PaLM 2 family, it is important to distinguish between pre-trained models (of various sizes), fine-tuned variants of these models, and the user-facing products that use these models. In particular, user-facing products typically include additional pre- and post-processing steps. Additionally, the underlying models may evolve over time. Therefore, one should not expect the performance of user-facing products to exactly match the results reported in this report