Summer Nights Research Articles

Antipredator responses of bats during short boreal nights with variable climatic conditions

Abstract The threat of predation can influence the behavior of animals. To minimize the impact of predation, animals rely on antipredatory responses and effectively balance these responses with other activities to maximize survival. Boreal bats are nocturnal animals that must forage within a narrow time frame during short, light summer nights with unpredictable weather. Despite having no specialized predators, boreal bats are still subject to predation. However, whether they express antipredatory responses has not been established. We studied antipredatory responses and responses to climatic conditions in boreal bats in 2 settings: 1) during roost emergence; and 2) during foraging within Tawny Owl territories and at locations with no Tawny Owl sightings. Acoustic data were collected at 23 roosts and 10 foraging grounds. Two controlled predation threats were used—playbacks of Tawny Owl calls and fledgling calls. Fledgling calls were only played during roost emergence. In both experiments, music and no treatment were used as controls. We also incorporated weather variables in the model. According to our results, bats tend to delay their emergence by 16 min when Tawny Owl calls were played outside the roost, but this effect was not noticeable when weather variables were included. There was no difference in exit time when music or fledgling sounds were played. While foraging, bats reduced their activity in Tawny Owl territories when calls of owls or music were played compared to no treatment. These results suggest that bats might display variable antipredatory responses, but weather influences behavior of bats more than predation risk, highlighting the importance of energy-saving strategies at northerly latitudes.

Heat Stress Metrics, Trends, and Extremes in the Southeastern United States

Abstract Humid heat and associated heat stress have increased in frequency, intensity, and duration across the globe, particularly at lower latitudes. One of the more robust metrics for heat stress impacts on the human body is wet-bulb globe temperature (WBGT), because it incorporates temperature, humidity, wind speed, and solar radiation. WBGT can typically only be measured using nonstandard instrumentation (e.g., black globe thermometers). However, estimation formulas have been developed to calculate WBGT using standard surface meteorological variables. This study evaluates several WBGT estimation formulas for the southeastern United States using North Carolina Environment and Climate Observing Network (ECONet) and U.S. Military measurement campaign data as verification. The estimation algorithm with the smallest mean absolute error was subsequently chosen to evaluate summer WBGT trends and extremes at 39 ASOS stations with long continuous (1950–2023) data records. Trend results showed that summer WBGT has increased throughout much of the southeastern United States, with larger increases at night than during the day. Although there were some surprisingly large WBGT trends at higher elevation locations far from coastlines, the greatest increases were predominantly located in the Florida Peninsula and Louisiana. Increases in the intensity and frequency of extreme (90th percentile) WBGTs were particularly stark in large coastal urban centers (e.g., New Orleans, Tampa, and Miami). Some locations like New Orleans and Tampa have experienced more than two additional extreme heat stress days and nights per decade since 1950, with an exponential escalation in the number of extreme summer nights during the most recent decade. Significance Statement Humid heat and associated heat stress pose threats to health in the moist subtropical climate of the southeastern United States. Wet-bulb globe temperature (WBGT) is a robust metric for heat stress but must be estimated using complex algorithms. We first evaluated the accuracy of three WBGT algorithms in the southeastern United States, using measured verification data. Subsequently, we used the most accurate algorithm to investigate WBGT trends and extremes since 1950 in 39 cities. Results showed that summer heat stress has increased throughout the region, especially at night. Increases in the intensity and frequency of extreme heat stress were most prevalent at urban coastal locations in Florida and Louisiana, emphasizing the impacts of increased urbanization and evaporation on heat stress.

About Height of the Surface Air Layer by Sodar Data

Average empirical estimations of the surface air layer height in Moscow have been received by the data of long-term acoustic remote sensing of the atmosphere using MODOS Doppler sodar of METEK (Germany) production. Based on the assumption that the average conditions are close to neutral stratification, this height, as the top of the quasi-linear section of the average long-term wind velocity profile in semi-logarithmic coordinates, is 40–60 m. The wind rotation height, i. e. the height of intersection of day and night wind profiles is on average 95 meters per year. The roughness length in conditions of loose but high urban development in vicinity of Moscow State University in Moscow is 5 m. According to the criterion of the constant wind direction in the surface air layer, its height appears in the average monthly wind direction profiles over the “dead zone” of the sodar (40 m) in approximately one case out of three and usually amounts to 60 m, less often 80 or 100 m. In the rest cases, it is apparently masked by “dead zone”. The average height of the surface layer according to this approach is probably a little less than 50 m, which is close to the estimate obtained from the logarithmic distribution of wind velocity with height in this layer. The daily course of the surface air layer height is noted by the largest values in the afternoon (80–100 m in summer under conditions of prevailing unstable stratification and 60–80 m in winter) and the smallest ones (less than 40 m) in the late evening and at night in summer and from evening to noon in winter.

A Psychoanalytical Approach to the Short Stories The Owner of the House, Summer Night and Train Journey by Ahmet Hamdi Tanpinar

The paper deals with the psychoanalytical approach to dreams and the unconscious in three short stories by the Turkish author Ahmet Hamdi Tanpınar. Insight into the nature of the human psyche and language as a medium of expression will be based on the works of Sigmund Freud and Jacques Lacan. The psychoanalytical literature that we will use in this research will represent the fundamental theoretical basis on which we will try to valorize the above-mentioned stories. As part of the reading of the short stories The Owner of The House, Summer Night and Train Journey by the Turkish author Ahmed Hamdi Tanpınar, the emphasis will be on elements such as time, the past, dreams, the unconscious, the other or the personal history of the characters about the world they build within themselves. The identity crises experienced by the protagonists of the analyzed stories have their roots in childhood traumas, and dreams represent the key to uncovering the unconscious. By applying Freud's psychoanalysis to the text, they tried to reveal the symptoms of the text and the unconscious mechanisms whose meaning is hidden in images, symbols, and metaphors. In his short stories, we find the story of the collapse of the inner world of the hero, of their escape from reality and continuous search, while the subject(s) of the text itself is constructed through its past, or more precisely, it is defined by a complex of events and people from the past.

Observation and modeling of an unusual spatiotemporal pattern in bioacoustic chorusing

This paper describes an unusual underwater biological chorus recorded in the Southern California Bight and presents a numerical modeling approach that replicates aspects of the chorus. During one experiment, the evolution of the directionality of the chorusing region over time is suggestive of “The Wave”, the human waves performed by fans periodically standing and sitting in sports stadia around the world; here, the region of chorusing periodically propagated upcoast over 20 km of coastline at nearly 1.5 km/s. The chorus occurs predominantly at night in spring and summer, mostly in very shallow waters near the coast. It increases the underwater sound field levels within chorusing regions by 20–30 dB in the 50 Hz to 1 kHz frequency band. The chorus is composed of three parts; 1) a “sunset chorus” which is a 20-to-30 min continuous roar around sunset with received spectral levels up to 100 dB re 1 μPa2/Hz, 2) a “sunrise chorus” of lower level than the sunset chorus, and 3) an all-night-long cycling chorus. The cycling portion is made up of 15-to-20 s periods of higher received spectral levels (up to 90 dB re 1 μPa2/Hz within the chorusing region) each followed by a 10-to-20 s lull in which the spectral levels drop by 4–10 dB. This alternating pattern repeats every 30–40 s throughout the night. The numerical modeling approach is based on the physics of excitable media. A cellular automaton is used to model the two-dimensional spatial grid occupied by the calling animals (units), with each unit being either in the “resting”, “excitable”, or “active (calling)" state at each time step. Transition from resting to excitable and from active back to resting occurs automatically after a fixed period of time in the present state, whereas the probability of transitioning from excitable to active is determined not only by the elapsed time since entering the excitable state, but also by the received sound level at the unit location, creating a non-linear acoustics-based coupling between units. With appropriate inputs, many determined from measurements of the chorus properties and the individual animal calls themselves, simulations with the model can replicate the cycling levels in the night-long chorus, the continuous din of the sunset chorus, and (once properly initialized) the periodic upcoast evolution of the chorusing region (“The Wave”). When noise from a transiting ship is included in the simulations, the spatiotemporal characteristics of the chorus change appreciably, in ways similar to changes observed during the experiment.

On a Summer Night by Deborah Hopkinson (review)

On a Summer Night by Deborah Hopkinson (review)

“Nuit Persane” by C. Saint-Saëns: Oriental Story from a Frenchman

“Nuit Persane” by C. Saint-Saëns: Oriental Story from a Frenchman

Prospects and challenges for the development of Arctic tourism in the Republic of Sakha (Yakutia)

The Arctic territories have unique natural and cultural features that attract tourists from all over the world. These features include unique landscapes, a wealth of flora and fauna, as well as the traditions and customs of the indigenous peoples of the North. The geographical location of the Arctic territories plays an important role in their attractiveness to tourists. They are located at high latitudes, with long nights and short days in winter, and longer days and shorter nights in summer. Arctic tourism is becoming an increasingly popular form of recreation around the world. The Republic of Sakha (Yakutia) is located in the north of Eastern Siberia, has access to two seas – the East Siberian and the Laptev, about 40 % of the territory of the Republic is in the Arctic zone of the Russian Federation. This work contains a clarification of the definition of the concept of «Arctic tourism», identification of the most popular types of tourist services characteristic of the Arctic, as well as a comparative analysis of trends and prospects for the development of Arctic tourism in the territory of 13 regions of the Republic of Sakha (Yakutia) included in the Arctic zone of the Russian Federation. The author draws conclusions regarding the prospects for the development of Arctic tourism on the territory of the Republic of Sakha (Yakutia). The Arctic is a unique region that attracts the attention of many tourists. However, due to its inaccessibility and the fragility of the ecosystem, it is necessary to carefully approach the development of routes and the regulation of tourism activities.

Impact of climate change on the potential of free-cooling strategies for a retrofitted building in a hot climate

This paper’s objective and novelty is to understand the impact of different natural ventilation strategies as well as the effect of a proposed smart controlled ventilation strategy on cooling energy saving and thermal comfort in a residential building. Afterwards, an investigation of the Climatic Potential of Natural Ventilation (CPNV) in hot and dry climates, and particularly the potential of the night ventilation strategy under present and future climates, was made. Two prediction climate change scenarios, RCPs 2.6 and 8.5, were considered for two periods. The results, obtained by a validated simulation, have shown the beneficial effect of night ventilation, since it could reduce cooling load by 9% and would keep the operative temperature below 30°C. Nevertheless, the potential of this natural ventilation strategy would be reduced in the future due to climate change. Indoor overheating has been projected to increase drastically. The summer thermal behaviour will be greatly aggravated in the future. Indeed, the CPNV in the summer nights will be decreased by 25%. However, the climate change will affect the winter natural ventilation potential in the future. The results also highlighted that the annual Total Climatic Potential of Natural Ventilation could be increased by 1% for RCP 2.6 and decreased by 4.9% for RCP 8.5.

Seasonal phenology of the little brown bat (Myotis lucifugus) at 60° N

AbstractTo investigate the impact of short summers and long summer solar periods at high latitudes on the behavior of a nocturnal, hibernating mammal, we recorded the phenology of Myotis lucifugus (little brown myotis) at 60° N in the Northwest Territories (NWT), Canada. In particular, we assessed the timing of spring emergence from, and autumn entry into, hibernation, reproduction, and seasonal mass fluctuations. We used a combination of acoustic monitoring and capture surveys at two hibernacula and two maternity roosts during 2011 and 2012. Myotis spp. were active at the hibernacula from late April to late September/early October, suggesting that the “active” season length is similar to that of populations farther south. At maternity colonies, we detected M. lucifugus activity from early May to early October, with peaks during mid‐July in both years. Lactation, fledging, and weaning all occurred later in the NWT than at more southern locations, and reproductive rates were significantly lower than rates observed farther south. The average mass of individuals fluctuated throughout the season, with an initial decline immediately following emergence from hibernation likely reflecting increased energy expenditure due to flight and decreased use of torpor, coupled with relatively low prey intake due to low prey abundance associated with cool temperatures. Females did not appear to have lower pre‐hibernation masses than those in more southern populations, suggesting that despite the cool spring and autumn temperatures, and short summer nights, bats are able to obtain enough energy for reproduction and mass accumulation for hibernation. However, the lower reproductive rates may indicate that there are limitations to life at the northern limits of the species' range.

Experimental and numerical investigation on the charging and discharging process of a cold energy storage for space cooling of buildings

To address the current issue of the difficulty to use the hot outdoor environment during summer nights to provide coolness for phase change materials (PCM) and thus reduce building energy consumption in hot summer areas, a novel cold energy storage unit has been proposed. It replaces the hot outdoor environment with other free or cheap cold sources. An experimental setup is built to investigate the cold storage and release performance of the PCM storage unit. Later, the well-validated numerical model is conducted to further explore thermal performance of the PCM storage unit. The numerical result indicates that the cold storage process can be completed from 64.33 min to 96.56 min when the water inlet temperature varies from 10 °C to 16 °C. Further, during the cold release process, the PCM storage unit can reduce the temperature of the hot air by a maximum of about 8–12 °C when the air inlet temperature ranges from 32 °C to 38 °C. The cold release efficiency is varied between 81.65 % and 96.44 %. In conclusion, the findings provide a promising way for cold storage and space cooling of buildings in hot summer areas through the cold energy storage unit.

Нечітка система керування електротехнічним комплексом вуличного освітлення населених пунктів

The article deals with the issue of improving the energy efficiency of electrical systems that provide comfortable living conditions for the population of cities and towns, namely street lighting. A fuzzy control system for a group of LED luminaires of a road section is created that regulates the power of the lighting devices and, accordingly, their brightness and controls the connection to a power source (either to the grid or to a battery) depending on the level of illumination, traffic intensity and electricity tariff. It was found that a controlled system with combined power supply is more efficient. It reduces electricity consumption on a typical summer night by 75.31% and 74.93%, and on a winter night by 80.4% and 77.68% compared to the traditional street lighting option, when the lighting network is either completely shut down at night or operates at only 50% of capacity, respectively. It can be stated that the fuzzy control system for the electrical complex of street lighting is energy efficient. It is also recommended that specialized enterprises in settlements responsible for the lighting network pay more attention not only to replacing light sources with new, more energy-efficient ones, but also to introducing alternative power sources for lighting installations that allow charging batteries during daylight hours, such as solar panels. This, along with the use of the fuzzy control system under consideration, will make it possible to save even more on electricity costs, which is very important in today's environment.

OBSERVATIONS OF THE SUPERNOVA SN2023IXF

Residing in a spiral arm of the Pinwheel Galaxy (M101), Supernova SN2023ixf was distinguished as one of the most intrinsically luminous objects visible in the 2023 summer night sky. Its astronomical significance is further highlighted by its relative proximity, situated at 6.64 Mpc. Over a span of 22 days, photometric observations were meticulously conducted by the GTRI team to analyze this supernova.

Thermal characteristics of dwellings with bamboo-woven mud walls in summer: A case study

Bamboo is a rapidly regenerating resource that can be used as a substitution for primary building materials with high embodied carbon. However, the bamboo-woven mud wall, which is a unique and low-cost enclosure wall, has received limited attention in previous studies. To assess the thermal performance of this construction during summer, this work conducted field measurements on a traditional dwelling with bamboo-woven mud walls (Building A) and a reference brick-concrete dwelling (Building B) in the hot and humid area with abundant bamboo resources. The experimental findings indicate that while Building A is more sensitive to temperature changes compared to Building B, it proves to be more suitable for the hot and humid climate, especially during summer nights. On the contrary, Building B is characterized by its substantial weight and is more favorable during summer days. Furthermore, through optimizing the construction of bamboo-woven mud walls and implementing adjustable natural ventilation techniques, the traditional bamboo building can be retrofitted using cost-effective local methods. This study demonstrates superior overall thermal performance and improved thermal stability of vernacular dwellings with bamboo-woven mud walls in hot and humid regions, in comparison to modern brick-concrete structures. These findings also serve as a valuable reference for the ongoing development of affordable, climate-responsive passive buildings.

A new heat and cold storage system to enhance the thermal autonomy of residential buildings

We integrated 18 kg of PCM in 80 cells of a plate heat exchanger which were placed between a water charge and an air discharge circuit fed by the air renewal. The 0.1 m3 thermal battery can replace radiators to heat and cool, store heat and cold and perform air renewal independently for each room. The narrow PCM cells and the relatively large temperature difference between the PCM with fusion temperature of 25°C and the renewed air allowed to achieve average discharge powers of 300W and 440W for heating and cooling respectively. The integrated total heat and cold storage capacities were found to be 1.5 kWh and 1.8 kWh respectively. By replacing each radiator of a house with such a battery substantial thermal storage can be achieved. The liquid thermal battery, cooled with outdoor air of 17°C, completely solidified in less than 7h. This means that cool summer nights can charge the PCM to cool the room the following day.

Seasonal variation in sleep time: jackdaws sleep when it is dark, but do they really need it?

Sleep is an important behavioural and physiological state that is ubiquitous throughout the animal kingdom. Birds are an interesting group to study sleep since they share similar sleep features with mammals. Interestingly, sleep time in birds has been shown to vary greatly amongst seasons. To understand the mechanisms behind these variations in sleep time, we did an electro-encephalogram (EEG) study in eight European jackdaws (Coloeus monedula) in winter and summer under outdoor seminatural conditions. To assess whether the amount and pattern of sleep is determined by the outdoor seasonal state of the animals or directly determined by the indoor light–dark cycle, we individually housed them indoors where we manipulated the light–dark (LD) cycles to mimic long winter nights (8:16 LD) and short summer nights (16:8 LD) within both seasons. Jackdaws showed under seminatural outdoor conditions 5 h less sleep in summer compared to winter. During the indoor conditions, the birds rapidly adjusted their sleep time to the new LD cycle. Although they swiftly increased or decreased their sleep time, sleep intensity did not vary. The results indicate that the strong seasonal differences in sleep time are largely and directly driven by the available dark time, rather than an endogenous annual clock. Importantly, these findings confirm that sleep in birds is not a rigid phenomenon but highly sensitive to environmental factors.

The small-bat-in-summer paradigm: Energetics and adaptive behavioural routines of bats investigated through a stochastic dynamic model.

Strong seasonality at high latitudes represents a major challenge for many endotherms as they must balance survival and reproduction in an environment that varies widely in food availability and temperature. To avoid energetic mismatches caused by limited foraging time and stochastic weather conditions, bats employ the energy-saving state of torpor during summer to save accumulated energy reserves. However, at high-latitude small-bats-in-summer face a particular challenge: as nocturnal foragers, they rely on the darkness at night to avoid predators and/or interspecific competition, but live in an environment with short, light summer nights, and even a lack of true night at the northernmost distributions of some bat species. To predict optimal behaviour in relation to latitudinal variation in diurnal cycles, we constructed a stochastic dynamic programming model of bats living at high latitudes. Using a stochastic dynamic programming framework with values that are representative for our study system, we show that individual energetic reserves are a strong driver of daytime use of torpor and night-time foraging behaviour alike, with these linked effects being both temperature- and photoperiod-dependent. We further used the model to predict survival probabilities at five locations across a latitudinal gradient (60.1° N to 70.9° N), finding that combinations of photoperiod and temperature conditions limited population distributions in the model. To verify our model results, we compared predictions for optimal decisions with our own empirical data collected on northern bats (Eptesicus nilssonii) from two latitudes in Norway. The similarities between our predictions and observations provide strong evidence that this model framework incorporates the most important drivers of diurnal decision-making in bat physiology and behaviour. Comparing empirical data and model predictions also revealed that bats facing lighter night conditions further north restrict their mass gain, which strengthens the hypothesis that predation threat is a main driver of bat nocturnality. Our model findings regarding state-dependent decisions in bats should contribute to the understanding of how bats cope with the summer challenges at high latitudes.

Influence of meteorological factors and air pollutants on bacterial concentration across two urban areas of the Sistan region of Iran

This study assesses relationships between meteorological factors and air pollutants with ambient bacterial concentration. In the two main cities of Sistan, Zabol and Zahak, airborne bacteria concentration was monitored using the settle plate method inside and outside household environments during dusty days and nights in summer, autumn, and winter in 2022. As context for the study, it was determined that air quality index (AQI) values >100 on most sampling days in Zabol (51.9%) and Zahak (70.4%), with higher values in summer than autumn and winter. The lowest and highest bacterial concentrations in outdoor air were observed at AQI < 50 (good) and AQI > 300 (hazardous), respectively, in both cities. Bacterial concentration showed a decreasing trend from summer to winter, which coincided with a decreasing trend of air pollutant indices, wind speed, and temperature in addition to an increasing trend of relative humidity. Temperature, relative humidity, and atmospheric pressure had negative correlations, while wind speed and air pollutant indices (PM10, PM2.5 and AQI) showed positive correlations and wind direction had no correlation with bacterial concentrations. The factors best related to bacterial concentrations were air quality indices (PM10, PM2.5 and AQI) in both cities, with the highest levels driven by dust storms in Sistan.

Influence of coastal planetary boundary layer on PM2.5 with unmanned aerial vehicle observation

Field measurement with an Unmanned Aerial Vehicle (UAV) platform was conducted at coastal area of Bohai in winter and summer. 135 flights were obtained and characteristics of boundary layer structure and its influence on PM2.5 were studied. The averaged profiles showed that meteorological parameters and PM2.5 changed significantly below 300 m. Weak suspension inversion existed between 30–300 m in the morning, ground inversion existed below 70 m at night in winter, temperature inversion was only observed below 200 m at night in summer. PM2.5 peaked at 300 m, 100 m and 200 m during morning, daytime and night period, respectively. During the middle and later stages of winter pollution episode, southwest and southeast wind, northwest and northeast wind formed obvious convergence at coastal area in turn, resulted in maximum PM2.5 concentration of 160 μg m−3 and 218 μg m−3 at night and morning, respectively. Isothermal layer was observed below 200 m, the maximum wind speed and high PM2.5 concentration all appeared at 200 m at night. Special stratification between 50–100 m was observed at 11:00, where wind speed decreased and high PM2.5 concentration maintained. During the summer pollution episode, the sea breeze formed at 13:00 and ended at 22:00, sea breeze extend westward 50 km to the central urban area at 16:00. Thermal internal boundary layer formed below 100 m at 15:00 and extended upward to 150 m at 17:00, weak temperature inversion layer was observed between 50 m ∼ 100 m, the maximum wind speed was 8 m s−1, the wind direction changed from southeast to south, and maximum PM2.5 concentrations of 160 μg m−3 were observed at 100 m.

Exposure of Elderly People to Indoor Air Pollutants in Wanxia Nursing Home

The elderly residing in nursing homes are typically more advanced in age, have more health issues, and spend more time indoors than other elderly people. This study explored the indoor air quality in the Wanxia nursing home, the largest private nursing home in Chengdu, China, based on long-term measurement data. Air pollutant sensors measured the level of air pollution in the Wanxia nursing home from March 2021 to February 2022. This study obtained several important results: (1) The indoor air quality index (IAQI) of the Wanxia nursing home was at a low pollution level in spring, summer, and autumn, and at a moderate pollution level in winter. PM concentration played the most important role in determining indoor air quality; (2) During winter, the 24 h mean indoor concentrations of PM2.5 and PM10 were close to or even exceeded the standard limits. During winter and summer nights, indoor CO2 levels were very close to or greater than 1000 ppm. During spring and summer nights, the indoor TVOC concentrations exceeded the limit (0.45 mg/m3); (3) Apart from HCHO concentrations in autumn, the levels of other indoor air pollutants were significantly influenced by their outdoor levels. In addition, the seasonal indoor/outdoor (I/O) ratios of CO2 and TVOCs exceeded 1; and (4) Indoor CO2 levels were closely related to indoor temperature (Ta) and relative humidity (RH) in each season. PM10 concentration correlated with Ta and RH in summer, while PM2.5 concentration did not correlate with Ta and RH in winter. The indoor TVOC level positively correlated with RH. Lastly, the indoor HCHO level was minimally influenced by changes in Ta and RH. Due to the above results, this study proposes targeted strategies for improving indoor air quality in nursing homes.