Impacts of the COVID-19 lockdown on energy consumption in a Canadian social housing building.

The COVID-19 pandemic hit societies in full force in 2020 and compelled people all around the world to change their lifestyle. The time spent at home significantly surged during the pandemic and this change in occupancy can have a direct impact on building energy consumption. COVID-19 lockdowns also accelerated the transition towards telework, a trend that many expect to last. Changes in energy consumption under lockdown is thus a valuable asset to forecast how energy could be consumed in buildings in the future. Here, we aim to quantify the impacts of the COVID-19 lockdown on the energy consumption (electricity, hot water and space heating) in residential buildings by answering these two questions: (i) Did the lockdown lead to changes in total energy consumption?, and (ii) Did the lockdown lead to changes in consumption patterns (i.e. time of the day at which energy is consumed)? To do so, we compared the energy consumption measured in a 40-dwelling social housing building located in Quebec City (Canada) during four months of lockdown to those of the months that preceded the lockdown. It is found that consumption patterns for electricity and hot water changed for the first two months of the lockdown, when the most intensive lockdown measures were applied. Overall consumption slightly increased for these two energy expenditures, but the more important change was that consumption occurred throughout the day instead of being concentrated in the evening as observed before the lockdown. Results shed light on the impact of lockdown on energy bills for consumers and on how energy utilities might be solicited during this kind of episode.

Role of depleted initial energy reserves in early benthic phase mortality of six marine invertebrate species.

Insufficient energy reserves are widely considered to be a primary factor contributing to high rates of early benthic phase mortality among benthic marine invertebrates, but this hypothesis has been based mostly on indirect, observational evidence, and remains largely untested. We therefore examined the role of initial energy reserves in regulating survivorship and growth during the early benthic phase. Recently settled or hatched individuals of six invertebrate species were collected from natural populations, maintained without food, and their survivorship was monitored. Contrary to expectations, starved individuals of all six species had high survivorship through the critical first 10 days of the early benthic phase, with half of the species experiencing <2% mortality, and the remaining three species experiencing only 6%-12% mortality. For five of the six species, 50% mortality was reached only after ≥50 days of starvation. Additionally, no difference in short-term survivorship was detected among starved individuals of three different size classes (a proxy for energy reserves) of N. ostrina hatchlings. Finally, the effect of different durations of delayed feeding (0-50 days) on recovery (i.e., growth and survivorship) once food was made available revealed that duration of starvation prior to feeding can nevertheless have significant longer-term impacts on the proportion of individuals that survive or their ability to grow. Together, these findings suggest that depleted energy reserves are not a primary cause of high mortality at the start of the early benthic phase, as had previously been hypothesized. Levels of energy reserves did influence growth, however, suggesting a possible indirect influence on performance by leaving individuals vulnerable for longer periods.

Implications of acute temperature and salinity tolerance thresholds for the persistence of intertidal invertebrate populations experiencing climate change.

To predict whether populations of marine animals will persist in the face of changing climate conditions, it is informative to understand how past climate conditions have shaped present-day tolerance thresholds. We examined 4 species of intertidal invertebrates (Nucella lamellosa, Littorina scutulata, Littorina sitkana, and Balanus glandula) inhabiting the coasts of Vancouver Island, Canada, where the east coast experiences historically warmer sea surface temperature (SST), warmer low tide (i.e., emersion) rock surface temperature (RST), and lower sea surface salinity (SSS) than the west coast. To determine if east coast populations have higher tolerance thresholds to acute stress than west coast populations, animals from 3 sites per coast were exposed to stressful temperatures and salinities in common garden experiments. Emersion temperature tolerance differed between populations only in N. lamellosa and B. glandula, tolerance thresholds being 1.4-1.5°C higher on the east coast. Water temperature tolerance differed between populations only in B. glandula and L. scutulata but was highest on the west coast. No differences in salinity tolerance were observed within any species. Thus, there is limited evidence of divergence among east and west coast populations in tolerance of acute stress despite the substantial historical differences in extreme temperature and salinity conditions between coasts. However, based on present-day summertime SST and RST and known rates of change in these parameters, we predict present-day tolerance thresholds would be sufficient to allow adults of these populations to tolerate extreme temperatures predicted for the next several hundred years, and that even a slow rate of change in acute tolerance thresholds might suffice to keep up with future temperature extremes.

How health managers can use data mining for predicting individuals' risks of contracting nosocomial pneumonia.

This article explains how managers can use a new data-mining technique for solving problems related to individual risks of contracting nosocomial pneumonia. Using the genetic algorithm, a search technique provides practitioners with an optimal choice of parameters for Gini boosting type decision tree models. Thus, managers and technicians can choose better models. These new parameters are genetically controlled: number of trees, depth of trees, trimming factor, cross-validation (to avoid overfitting), proportion of the population used, and the minimum size to split a node. This technique has been satisfactorily tested on health data.

A review of thermal response test analysis using pumping test concepts.

The design of ground-coupled heat pump systems requires knowledge of the thermal properties of the subsurface and boreholes. These properties can be measured with in situ thermal response tests (TRT), where a heat transfer fluid flowing in a ground heat exchanger is heated with an electric element and the resulting temperature perturbation is monitored. These tests are analogous to standard pumping tests conducted in hydrogeology, because a system that is initially assumed at equilibrium is perturbed and the response is monitored in time, to assess the system's properties with inverse modeling. Although pumping test analysis is a mature topic in hydrogeology, the current analysis of temperature measurements in the context of TRTs is comparatively a new topic and it could benefit from the application of concepts related to pumping tests. The purpose of this work is to review the methodology of TRTs and improve their analysis using pumping test concepts, such as the well function, the superposition principle, and the radius of influence. The improvements are demonstrated with three TRTs. The first test was conducted in unsaturated waste rock at an active mine and the other two tests aimed at evaluating the performance of thermally enhanced pipe installed in a fully saturated sedimentary rock formation. The concepts borrowed from pumping tests allowed the planning of the duration of the TRTs and the analysis of variable heat injection rate tests accounting for external heat transfer and temperature recovery, which reduces the uncertainty in the estimation of thermal properties.

Role of maternal provisioning in controlling interpopulation variation in hatching size in the marine snail Nucella ostrina.

This study examined the role of maternal provisioning in controlling interpopulation variation in hatching size in nine isolated populations of the intertidal gastropod Nucella ostrina, in which development to the early juvenile stage takes place within an egg capsule. Variation among populations was almost entirely due to the ratio of nurse eggs to embryo, which explained 65% of the variation in hatching size. Egg size was not a significant predictor of hatching size. Differences among seven of these populations in the nurse egg/embryo ratio were entirely due to the number of nurse eggs allocated per capsule; these populations allocated different numbers of nurse eggs per capsule but allocated the same number of embryos. Intriguingly, the two most wave-sheltered populations allocated significantly more nurse eggs and more embryos to each capsule than did the seven other populations, but they maintained nurse egg/embryo ratios consistent with patterns observed in the other populations. Inter- and intrapopulation variation in hatching size appears to be controlled largely by different mechanisms: within-population variation being controlled mainly by differences in allocation of embryos per capsule, whereas most among-population variation being due to differences in allocation of nurse eggs per capsule.