Electric Utility Alignment with the SDGs & the Paris Climate Agreement

The 2030 Sustainable Development Agenda poses a unique and critical challenge to the energy sector: how to scale access to clean energy to power sustainable, economic development for a growing population, while simultaneously decarbonizing global energy supply. Expanding access to clean energy will play a crucial role in achieving nearly every one of the Sustainable Development Goals, including those related to agricultural production, health outcomes, educational performance, water systems, access to infrastructure, and reducing inequalities. However, practices by some actors in the energy sector, and continued over-reliance on greenhouse gas-intensive fossil fuels also undermine global efforts to mitigate climate change and maintain healthy ecosystems and populations, and can exacerbate global conflict and inequality. In recent years, a number of frameworks and standards have been created, to evaluate energy companies’ alignment to the SDGs and to help companies and investors improve performance and decision-making. While such initiatives are surely a step in the right direction, to date, many of these tools fail to account holistically for the ways that energy sector conduct could impact sustainable development, and how those impacts map onto each of the 17 SDGs. This failing has allowed companies to “cherry pick” their preferred reporting criteria while ignoring less convenient SDGs. Further, the lack of consensus around standards and evaluation metrics for SDG-aligned practice has led to broadly different conclusions about the same companies’ conduct, undercutting confidence in the utility of evaluation frameworks altogether. In order to assist both the energy and financial sectors in their alignment with the SDGs, CCSI and the UN Sustainable Development Solutions Network developed a conceptual framework to define SDG-aligned business practices in the energy sector, and in particular the utility sector. The conceptual framework, composed of four pillars and applied to the utility sector, is as follows: Product: Is the utility a leader in zero-carbon electricity generation and is the utility on the path to reach zero carbon emissions by 2050 or earlier? Production process: Is the utility’s production process socially and environmentally sustainable? Value chain responsibility: Is the utility’s supply and value chain aligned with the SDGs and PCA? Citizenship: Is the utility a good corporate citizen? The full report adapts the four pillar framework to the utility sector, evaluates the proposed framework against twelve existing sustainability initiatives, and compares the performance of the ten largest utilities in Europe and the United States, by market capitalization. The report also provides recommendations for next steps. The project aims at bringing coherence and rigor to SDG measurement, reporting, and tools, supporting engagement with the sector on responsible practices and enabling highly responsible SDG-oriented companies to set themselves apart from the rest

Deep learning predicts total knee replacement from magnetic resonance images

Knee Osteoarthritis (OA) is a common musculoskeletal disorder in the United States. When diagnosed at early stages, lifestyle interventions such as exercise and weight loss can slow OA progression, but at later stages, only an invasive option is available: total knee replacement (TKR). Though a generally successful procedure, only 2/3 of patients who undergo the procedure report their knees feeling ''normal'' post-operation, and complications can arise that require revision. This necessitates a model to identify a population at higher risk of TKR, particularly at less advanced stages of OA, such that appropriate treatments can be implemented that slow OA progression and delay TKR. Here, we present a deep learning pipeline that leverages MRI images and clinical and demographic information to predict TKR with AUC $0.834 \pm 0.036$ (p < 0.05). Most notably, the pipeline predicts TKR with AUC $0.943 \pm 0.057$ (p < 0.05) for patients without OA. Furthermore, we develop occlusion maps for case-control pairs in test data and compare regions used by the model in both, thereby identifying TKR imaging biomarkers. As such, this work takes strides towards a pipeline with clinical utility, and the biomarkers identified further our understanding of OA progression and eventual TKR onset.Comment: 18 pages, 5 figures (4 in main article, 1 supplemental), 8 tables (5 in main article, 3 supplemental). Submitted to Scientific Reports and currently in revisio

A sluggish random walk with subdiffusive spread

We study a one-dimensional sluggish random walk with space-dependent transition probabilities between nearest-neighbour lattice sites. Motivated by trap models of slow dynamics, we consider a model in which the trap depth increases logarithmically with distance from the origin. This leads to a random walk which has symmetric transition probabilities that decrease with distance $|k|$ from the origin as $1/|k|$ for large $|k|$. We show that the typical position after time $t$ scales as $t^{1/3}$ with a nontrivial scaling function for the position distribution which has a trough (a cusp singularity) at the origin. Therefore an effective central bias away from the origin emerges even though the transition probabilities are symmetric. We also compute the survival probability of the walker in the presence of a sink at the origin and show that it decays as $t^{-1/3}$ at late times. Furthermore we compute the distribution of the maximum position, $M(t)$, to the right of the origin up to time $t$, and show that it has a nontrivial scaling function. Finally we provide a generalisation of this model where the transition probabilities decay as $1/|k|^\alpha$ with $\alpha >0$.Comment: 17 pages, revised version accepted for J. Stat. Mec

Conformations, Transverse Fluctuations and Crossover Dynamics of a Semi-Flexible Chain in Two Dimensions

We present a unified scaling description for the dynamics of monomers of a semiflexible chain under good solvent condition in the free draining limit. We consider both the cases where the contour length $L$ is comparable to the persistence length $\ell_p$ and the case $L\gg \ell_p$. Our theory captures the early time monomer dynamics of a stiff chain characterized by $t^{3/4}$ dependence for the mean square displacement(MSD) of the monomers, but predicts a first crossover to the Rouse regime of $t^{2\nu/{1+2\nu}}$ for $\tau_1 \sim \ell_p^3$, and a second crossover to the purely diffusive dynamics for the entire chain at $\tau_2 \sim L^{5/2}$. We confirm the predictions of this scaling description by studying monomer dynamics of dilute solution of semi-flexible chains under good solvent conditions obtained from our Brownian dynamics (BD) simulation studies for a large choice of chain lengths with number of monomers per chain N = 16 - 2048 and persistence length $\ell_p = 1 - 500$ Lennard-Jones (LJ) units. These BD simulation results further confirm the absence of Gaussian regime for a 2d swollen chain from the slope of the plot of $\langle R_N^2 \rangle/2L \ell_p \sim L/\ell_p$ which around $L/\ell_p \sim 1$ changes suddenly from $\left(L/\ell_p \right) \rightarrow \left(L/\ell_p \right)^{0.5}$, also manifested in the power law decay for the bond autocorrelation function disproving the validity of the WLC in 2d. We further observe that the normalized transverse fluctuations of the semiflexible chains for different stiffness $\sqrt{\langle l_{\bot}^2\rangle}/L$ as a function of renormalized contour length $L/\ell_p$ collapse on the same master plot and exhibits power law scaling $\sqrt{\langle l_{\bot}^2\rangle}/L \sim (L/\ell_p)^\eta$ at extreme limits, where $\eta = 0.5$ for extremely stiff chains ($L/\ell_p \gg 1$), and $\eta = -0.25$ for fully flexible chains.Comment: 14 pages, 18 figure

A Volume-Limited Sample of Ultracool Dwarfs. II. The Substellar Age and Mass Functions in the Solar Neighborhood

We present the most precise constraints to date for the mass and age distributions of single ultracool dwarfs in the solar neighborhood, based on an updated volume-limited sample of 504 L, T, and Y dwarfs within 25 pc. We develop a Monte Carlo approach using the $\langle V/V_{\rm max}\rangle$ statistic to correct for incompleteness and obtain a space density of $(1.83_{-0.15}^{+0.16})\times10^{-2}$ pc$^{-3}$ for spectral types L0-Y2. We calculate bolometric luminosities for our sample, using an updated "super-magnitude" method for the faintest objects. We use our resulting luminosity function and a likelihood-based population synthesis approach to simultaneously constrain the mass and age distributions. We employ the fraction of young L0-L7 dwarfs as a novel input for this analysis that is crucial for constraining the age distribution. For a power-law mass function $\frac{dN}{dM} \propto M^{-\alpha}$ we find $\alpha=0.58_{-0.20}^{+0.16}$, indicating an increase in numbers toward lower masses, consistent with measurements in nearby star-forming regions. For an exponential age distribution $b(t) \propto e^{-\beta t}$ we find $\beta=-0.44\pm0.14$, i.e., a population with fewer old objects than often assumed, which may reflect dynamical heating of the Galactic plane as much as the historical brown dwarf birthrate. We compare our analysis to Kirkpatrick et al. (2021), who used a similar volume-limited sample. Although our mass function measurements are numerically consistent, their assumption of a flat age distribution is disfavored by our analysis, and we identify several important methodological differences between our two studies. Our calculation of the age distribution of solar neighborhood brown dwarfs is the first based on a volume-limited sample.Comment: Accepted to ApJ. 49 pages, 14 figures, 6 table

COVID-19 Pandemic and Cardiovascular Disease

There seems to be a unique interplay between 2019 novel coronavirus (SARS-CoV-2) and cardiovascular diseases, although it is predominantly a respiratory illness. Patients with pre-existing cardiovascular co-morbidities appear to be at highest risk for mortality from coronavirus disease 2019 (COVID-19) along with the elderly; COVID-19 also contributes to cardiovascular complications, including acute coronary syndromes, arrhythmias, myocarditis, acute heart failure, and, in the most severe cases, cardiogenic shock and death. Several medications proposed in the treatment of COVID-19 require cardiac monitoring owing to their cardiac-specific adverse effects. Ultimately, the COVID-19 pandemic has jeopardized the safety of heart transplantation and has placed transplant recipients on immunosuppressive therapies at significant risk. In this article, the authors summarize the rapidly emerging data on the cardiovascular implications of SARS-CoV-2 and COVID-19

Comparison of open reduction internal fixation by lateral extensile approach versus conservative management in sanders type 2 and 3 calcaneum fractures: a prospective, two-arm, parallel group study

Background: Calcaneum bone is the most common tarsal bone to get fractured. It accounts for 50-60% of all fractured tarsal bones. Calcaneum fractures are always debilitating and are challenging and cumbersome to treat. There is a paucity of Indian studies to assess the comparative treatment outcomes of calcaneal fractures treated by non-operative conservative procedure and open reduction internal fixation by lateral extensile approach. Methods: Adult patients with closed intra-articular calcaneum fractures of Sanders type 2 and 3 were enrolled. Patients managed by cast application (non-operative) or open reduction internal fixation (operative) were separated into two groups. The VAS score for pain, range of motion, radiological angles (Bohler’s and Crucial angle of Gissane) and parameters, functional scores American orthopedic foot and ankle society and Maryland foot score were evaluated sixth month and 1-year post-intervention and compared between the study groups. Descriptive statistics were used for statistical analysis. Results: 29 patients managed with open reduction internal fixation (N=15) or cast application (N=14) were enrolled. The mean age of patients was 39.54±7.81 years, 22 being males and 7 females. Mean VAS score was significantly lower in the plating group at sixth month (4.31+0.69 vs. 5.01+0.66, p&lt;0.05) but not significant at 1 year (1.25+1.09 vs. 1.86+0.77, p&lt;0.05). Range of movements at the ankle and subtalar joints were higher in the operative group. Mean Bohler’s angle was significantly higher and Gissane’s angle lower in the operative group (p&lt;0.05). Significantly higher AOFAS and Maryland scores were noted in the operative group (p&lt;0.05). Subtalar arthritis with malunion was more common in the non-operative group. Conclusions: Operative open reduction and internal fixation methods were found to be significantly better than the conservative management of calcaneus fracture based on clinical, radiological and functional outcomes. Results are most favourable    if wound complications are minimized