A heterothermic spectrum in hummingbirds

Many endotherms use torpor, saving energy by a controlled reduction of their body temperature and metabolic rate. Some species (e.g., arctic ground squirrels, hummingbirds) enter deep torpor, dropping their body temperatures by 23-37°C, while others can only enter shallow torpor (e.g., pigeons, 3-10°C reductions). However, deep torpor in mammals can increase predation risk (unless animals are in burrows or caves), inhibit immune function, and result in sleep deprivation, so even for species that can enter deep torpor, facultative shallow torpor might help balance energy savings with these potential costs. Deep torpor occurs in three avian orders, but the trade-offs of deep torpor in birds are unknown. Although the literature hints that some bird species (mousebirds and perhaps hummingbirds) can use both shallow and deep torpor, little empirical evidence of such an avian heterothermy spectrum within species exists. We infrared imaged three hummingbird species that are known to use deep torpor, under natural temperature and light cycles, to test if they were also capable of shallow torpor. All three species used both deep and shallow torpor, often on the same night. Depending on the species, they used shallow torpor for 5-35% of the night. The presence of a heterothermic spectrum in these bird species indicates a capacity for fine-scale physiological and genetic regulation of avian torpid metabolism.

Ecohydrologie urbaine et changement climatique

Due to global change, cities of the future will have to deal with more intense runoff and longer drought sequences, in addition to a growing urban and peri-urban population. French Mediterranean cities, such as Toulon, are already densely urbanised and exposed to the effects of global warming. The adaptation of their infrastructures is problematic. Cities with high development potential, such as Dakar, offer the opportunity to imagine other solutions for the management of water resources and its extremes in the context of global change. In particular, it is a question of managing the flows of water and substances linked to intense runoff events according to an ecohydrological logic that makes it possible to reduce environmental risks and increase social and economic benefits. To do this, we use a hydrologically-based geomatics model (IRIP) that produces predictive maps of areas of generation, transfer and accumulation of intense runoff and associated nutrients. This allows us to target effective intervention areas to reduce risks and increase water resources, for example by simulating land use change in appropriate locations and at the same time stimulating specific biological processes. The fundamental principle of ecohydrology is to balance energy flows with biological metabolic flows at the sub-catchment scale. The mapping of intense runoff processes is a first step illustrated in this article for the cities of Toulon and Dakar. This first step is part of the Dakar'2030 project, which aims to rethink urban development and adapt it to climate change.

Towards Differentiated Energy Renovation Strategies for Heritage-Designated Multifamily Building Stocks

The historic building stock is not homogeneous, which implies a need for differentiated energy renovation strategies in order to balance energy efficiency requirements and building conservation goals. This paper presents a new method for developing a base for differentiated energy renovation strategies for heritage-classified multifamily building stocks. Our suggested method combines different building databases using an extract, transform and load (ETL) technology. The method for this study was tested on the available information for heritage-designated and -classified multifamily buildings in the municipality of Stockholm, Sweden, and in the county of Halland, Sweden. The two cases reflect the heterogeneity of the Swedish Building stock. An important achievement is that the results visualise the relationship, not detectable before, between energy use, energy performance, year of construction and heritage classification within each of the selected building stocks. A specific result is that the energy-saving potential in the older building stock is insignificant in relation to the entire stock. The results contribute to an improved understanding of relationships both within and between the two historic building stocks, which is useful for developing differentiated energy renovation strategies.

Method of Estimating the Carbon Footprint of Wastewater Treatment Plants

Wastewater treatment operations focus on removing pollutants from wastewater to meet water quality standards for public health and environmental protection. However, in recent decades new sustainability targets for wastewater treatment plants have been postulated and implemented, which assume that energy is one of the key elements. Therefore, a transition from a negative energy balance (energy demand covered by external sources) to an energy-neutral or unevenly positive energy balance of wastewater treatment has been postulated. The carbon footprint (CF) is a new measure of sustainability in the wastewater sector for determining the overall impact of wastewater treatment plants on climate change. The following paper presents a method for estimating and assessing the carbon footprint of wastewater treatment plants.

Online Machine Learning of Available Capacity for Vehicle-to-Grid Services during the Coronavirus Pandemic

Vehicle-to-grid services make use of the aggregated capacity available from a fleet of vehicles to participate in energy markets, help integrate renewable energy in the grid and balance energy use. In this paper, the critical components of such a service are described in the context of a commercial service that is currently under development. Key among these components is the prediction of available capacity at a future time. In this paper, we extend a previous work that used a deep learning recurrent neural network for this task to include online machine learning, which enables the network to continually refine its predictions based on observed behaviour. The coronavirus pandemic that was declared in 2020 resulted in closures of the university and substantial changes to the behaviour of the university fleet. In this work, the impact of this change in vehicles usage was used to test the predictions of a network initially trained using vehicle trip data from 2019 with and without online machine learning. It is shown that prediction error is significantly reduced using online machine learning, and it is concluded that a similar capability will be of critical importance for a commercial service such as the one described in this paper.

Social License to Automate: Emerging Approaches to Demand Side Management

The Social License to Automate Task has investigated the social dimensions of user engagement with automated technologies in energy systems to understand how end-user trust to automate is built and maintained in different jurisdictions and cultural settings. The rapid uptake of renewable energy systems will require new automated technologies to balance energy supplies. Some developers are looking to locate these in households where energy is being used. This saves moving the energy from centralised generation sites (remote hydro, solar or wind). This report details the findings from a 2 year project with 16 researchers in 6 countries, 26 Case studies spanning electric vehicles, home and precinct batteries, air conditioners and other heat pumps.

Facultative variation across a shallow to deep torpor spectrum in hummingbirds

Many small endotherms use torpor, saving energy by a controlled reduction of their body temperature and metabolic rate. Some species (e.g. arctic ground squirrels, hummingbirds) enter deep torpor, dropping their body temperatures by 23-37 °C, while others can only enter shallow torpor (e.g., pigeons, 3-10 °C reductions). However, deep torpor in mammals can increase predation risk (unless animals are in burrows or caves), inhibit immune function, and result in sleep deprivation, so even for species that can enter deep torpor, facultative shallow torpor might help balance energy savings with these potential costs. Deep torpor occurs in three avian orders. Although the literature hints that some bird species can use both shallow and deep torpor, little empirical evidence of such an avian torpor spectrum exists. We infrared imaged three hummingbird species that are known to use deep torpor, under natural temperature and light cycles, to test if they were also capable of shallow torpor. All three species used both deep and shallow torpor, often on the same night. Depending on the species, they used shallow torpor for 5-35% of the night. The presence of a bird torpor spectrum indicates a capacity for fine-scale physiological and genetic regulation of avian torpid metabolism.

Feed Abdominal Surgery Patients to Improve Outcomes

Malnourishment of surgical patients has long been recognized as contributing to postoperative morbidity and mortality.1,2 Early protocols calling for lengthy perioperative patient fasting have been replaced by interventions aimed at diagnosing and addressing each patient’s nutritional and metabolic needs; maintaining fluid and electrolyte balance, energy, and protein stores; and preserving muscle strength and gut microbiome by restoring oral feeding as soon as possible postoperatively.3 Interventions to achieve this physiologic balance have been the subject of considerable research, yet neither comprehensive preoperative programs4 nor early postoperative oral feeding5 have been reported to result in consistently improved clinical outcomes following abdominal surgery. This installment of Evidence Corner explores 2 systematic reviews, one of which presents clinical outcomes of early resumption of enteral food intake within 24 hours after gastrointestinal (GI) surgery,6 and the other presents clinical outcomes of perioperatively enhanced nutrition for those undergoing radical cystectomy (RC) for bladder cancer.7