Machine Learning-based Identification of Contaminated Images in Light Curve Data Preprocessing

Attitude is one of the crucial parameters for space objects and plays a vital role in collision prediction and debris removal.Analyzing light curves to determine attitude is the most commonly used method.In photometric observations,outliers may exist in the obtained light curves due to various reasons.Therefore,preprocessing is required to remove these outliers to obtain high quality light curves.Through statistical analysis,the reasons leading to outliers can be categorized into two main types:first,the brightness of the object significantly increases due to the passage of a star nearby,referred to as“stellar contamination,”and second,the brightness markedly decreases due to cloudy cover,referred to as“cloudy contamination.”The traditional approach of manually inspecting images for contamination is time-consuming and labor-intensive.However,we propose the utilization of machine learning methods as a substitute.Convolutional Neural Networks and SVMs are employed to identify cases of stellar contamination and cloudy contamination,achieving F1 scores of 1.00 and 0.98 on a test set,respectively.We also explore other machine learning methods such as ResNet-18 and Light Gradient Boosting Machine,then conduct comparative analyses of the results.

Understanding light pollution: Recent advances on its health threats and regulations

The prevalence of artificial lights not only improves the lighting conditions for modern society,but also poses kinds of health threats to human health.Although there are regulations and standards concerning light pollution,few of them are based on the potential contribution of improper lighting to diseases.Therefore,a better understanding of the health threats induced by light pollution may promote risk assessment and better regulation of artificial lights,thereby a healthy lighting environment.This review is based on a careful collection of the latest papers from 2018 to 2022 about the health threats of light pollution,both epidemiologically and experimentally.In addition to summing up the novel associations of light pollution with obesity,mental disorders,cancer,etc.,we highlight the toxicological mechanism of light pollution via circadian disruption,since light pollution directly interferes with the natural light-dark cycles,and damages the circadian photoentrainment of organisms.And by reviewing the alternations of clock genes and disturbance of melatonin homeostasis induced by artificial lights,we aim to excavate the profound impacts of light pollution based on accumulating studies,thus providing perspectives for future research and guiding relevant regulations and standards.

The effect of urbanization and exposure to multiple environmental factors on life-history traits and breeding success of Barn Swallows(Hirundo rustica)across China

In addition to landscape changes,urbanization also brings about changes in environmental factors that can affect wildlife.Despite the common referral in the published literature to multiple environmental factors such as light and noise pollution,there is a gap in knowledge about their combined impact.We developed a multidimensional environmental framework to assess the effect of urbanization and multiple environmental factors(light,noise,and temperature)on life-history traits and breeding success of Barn Swallows(Hirundo rustica)across rural to urban gradients in four locations spanning over 2500 km from North to South China.Over a single breeding season,we measured these environmental factors nearby nests and quantified landscape urbanization over a 1km~2radius.We then analysed the relationships between these multiple environmental factors through a principal component analysis and conducted spatially explicit linear-mixed effects models to assess their effect on lifehistory traits and breeding success.We were particularly interested in understanding whether and how Barn Swallows were able to adapt to such environmental conditions associated with urbanization.The results show that there is significant variation in the exposure to environmental conditions experienced by Barn Swallows breeding across urbanization gradients in China.These changes and their effects are complex due to the behavioural responses ameliorating potential negative effects by selecting nesting sites that minimize exposure to environmental factors.However,significant relationships between landscape urbanization,exposure to environmental factors,and life-history traits such as laying date and clutch size were pervasive.Still,the impact on breeding success was,at least in our sample,negligible,suggesting that Barn Swallows are extremely adaptable to a wide range of environmental features.

Introduction to the environmental monitoring instruments for LOT

The Large Optical/infrared Telescope(LOT)is a ground-based 12 m diameter optical/infrared telescope,which is proposed to be built in the western part of China in the next decade.To select the best site which satisfies the construction and future operation of LOT,data monitoring and comparing are required for all the candidate sites.The comparison of most of the instruments was done at Xinglong Observatory.These instruments include weather station,all sky camera,sky background meter and differential image motion monitor(DIMM).This paper introduces the instruments used in LOT site monitoring and the instruments comparisons.The results show that the instrument is stable and the data uniformity of the identical instruments is good.This paper provides a fundamental description of LOT site monitoring.

Spatial Model of Sky Brightness Magnitude in Langkawi Island, Malaysia

Sky brightness is an essential topic in the field of astronomy, especially for optical astronom- ical observations that need very clear and dark sky conditions. This study presents the spatial model of sky brightness magnitude in Langkawi Island, Malaysia. Two types of Sky Quality Meter （SQM） manu- factured by Unihedron are used to measure the sky brightness on a moonless night （or when the Moon is below the horizon）, when the sky is cloudless and the locations are at least 100 m from the nearest light source. The selected locations are marked by their GPS coordinates. The sky brightness data obtained in this study were interpolated and analyzed using a Geographic Information System （GIS）, thus producing a spatial model of sky brightness that clearly shows the dark and bright sky areas in Langkawi Island. Surprisingly, our results show the existence of a few dark sites nearby areas of high human activity. The sky brightness of 21.45 mag arcsec-2 in the Johnson-Cousins V-band, as the average of sky brightness equivalent to 2.8 × 10-4cd m-2 over the entire island, is an indication that the island is, overall, still relatively dark. However, the amount of development taking place might reduce the number in the near future as the island is famous as a holiday destination.

Influence of night-time light pollution on the photosynthesis and physiological characteristics of the urban plants Euonymus japonicus and Rosa hybrida

Background Night-time light pollution(NLP),which breaks the natural cycle of day and night,has become a new threat to urban ecosystems.Plants are the main component of urban ecosystems and play an irreplaceable role in maintaining urban ecological balance.The effects of NLP with various radiation sources,including green,white,blue and red light provided by light-emitting diodes,on urban plants,Euonymus japonicus and Rosa hybrida,were examined in a block field experiment.Results NLP caused photoinhibition and oxidative stress in plants,and the extent of the deleterious effects varied with the spectral distribution of artificial light sources and species.Both E.japonicus and R.hybrida were more sensitive to blue and red light,which reduced the pigment concentration,net photosynthetic rate,stomatal limit value,effective quantum yield,apparent electron transfer rate and photochemical quenching coefficient,and markedly increased the malondialdehyde content and total antioxidant capacity.However,those negative effects under white light were only present in E.japonicus and not in R.hybrida.Furthermore,blue and red light significantly decreased the stomatal conductance of E.japonicus.In contrast,green light had no significant effect on the above indices for both species.All spectra did not significantly change the sugars and starch contents for either species.Conclusions Considering that the spectral distribution of artificial light at night in cities has great heterogeneity and that its effect varies with plant species,it is important to arrange tree species with NLP tolerance and install appropriate light sources in urban areas based on the corresponding physiological responses and adaptation of urban trees.

Embracing digital mindsets to ensure a sustainable future

The 19th Asian Games astounded global audiences with an opening spectacle that showcased stunning digital fireworks(International Olympic Committee,2021;Zhe,2023).The groundbreaking display was brought to life through virtual reality(VR)and augmented reality(AR)technologies.It sets a pioneering example to replace conventional fireworks in major international events as well as in other large-scale entertainment activities,marking a historic milestone in the pursuit of a sustainable and healthy future.

Artificial light at night decreases the pupillary light response of dark-adapted toads to bright light

Artificial light at night(ALAN)is expanding worldwide.Many physiological effects have been reported in animals,but we still know little about the consequences for the visual system.The pupil contributes to control incoming light onto the retina.Sudden increases in light intensity evokes the pupil light reflex(PLR).Intrinsically photosensitive retinal ganglion cells(ipRGC)affect PLR and melatonin expression,which largely regulate circadian rhythms and PLR itself.IpRCG receive inputs from various photoreptors with different peak sensitivities implying that PLR could be altered by a broad range of light sources.We predicted ALAN to enhance PLR.Contrary to our prediction,dark-adapted cane toads Rhinella marina,exposed to ALAN(5 lx)for 12 days,exhibited a lower PLR than controls and individuals exposed to 0.04 lx,even after 1 h in bright light.We cannot conclude whether ALAN induced a larger pupil size in dark-adapted toads or a slower initial contraction.Nevertheless,the response was triggered by a light source with an emission peak(590 nm)well above the sensitivity peak of melanopsin,the main photoreceptor involved in PLR.Therefore,ALAN alters the capacity of toads to regulate the incoming light in the eye at night,which may reduce the performance of visually guided behaviors,and increase mortality by predators or road kills at night.This first study emphasizes the need to focus on the effect of ALAN on the vision of nocturnal organisms to better understand how this sensory system is altered and anticipate the consequences for organisms.

Bright artificial light at night is associated with increased body mass,poor reproductive success and compromised disease tolerance in Australian budgerigars(Melopsittacus undulatus)

Artificial light at night(ALAN)can cause circadian disruption and result in adverse behavioral and ecologi­cal effects in free-living birds,but studies on captive pet birds as companion animals have been infrequent.We studied the effects of exposure to bright ALAN on body mass,melatonin sulfate levels,reproduction and dis­ease severity in Australian budgerigars(Melopsittacus undulatus)kept in captivity.During the experiment,birds were kept under outdoor temperature,humidity and natural photoperiod from September to December.A total of 48 birds were equally split into 4 groups(6 mating pairs each)and concurrently exposed to ALAN of 200 lux with different duration(0,30,60 and 90 min).Monthly observations were recorded for all dependent parame­ters.ALAN exposure increased mass gain and suppressed melatonin levels in a dose-dependent manner,espe­cially during December.In addition,ALAN exposure in all duration groups decreased egg production and re­duced hatchability from 61%±14%in the ALAN-unexposed control group to 0%in the ALAN-exposed birds.Disease severity was also found to increase in line with the duration of ALAN exposure.In captive M.undu­latus,ALAN exposure was demonstrated to affect photoperiodic regulation with subsequent excess mass gain and reproduction impairment,and increased susceptibility to infections plausibly through duration dose-depen­dent suppression of melatonin.To the best of our knowledge,this is the first study to demonstrate a possible as­sociation between acute bright ALAN of increasing duration and both natural development of infections as well as reproductive cessation in captive birds.Our findings could be used to improve breeding conditions of captive birds.

Charge transfer between biogenic jarosite derived Fe^3＋ and TiO2 enhances visible light photocatalytic activity of TiO2

In this work, we have shown that mining waste derived Fe^3＋can be used to enhance the photocatalytic activity of TiO2. This will allow us to harness a waste product from the mines, and utilize it to enhance TiO2 photocatalytic waste water treatment efficiency. An organic linker mediated route was utilized to create a composite of TiO2 and biogenic jarosite. Evidence of Fe／O／Ti bonding in the TiO2/jarosite composite was apparent from the FTIR, EFTEM, EELS and ELNEFS analysis. The as prepared material showed enhanced photocatalytic activity compared to pristine TiO2, biogenic jarosite and mechanically mixed sample of jarosite and TiO2 under both simulated and natural solar irradiation. The prepared material can reduce the electrical energy consumption by 4 times compared to pristine P25 for degradation of organic pollutant in water. The material also showed good recyclability. Results obtained from sedimentation experiments showed that the larger sized jarosite material provided the surface to TiO2 nanoparticles, which increases the settling rate of the materials. This allowed simple and efficient recovery of the catalyst from the reaction system after completion of photocatalysis. Enhanced photocatalytic activity of the composite material was due to effective charge transfer between TiO2 and jarosite derived Fe^3＋as was shown from the EELS and ELNEFS. Generation of OHU was supported by photoluminesence（PL） experiments.

Dim artificial light at night reduces the cellular immune response of the black field cricket, Teleogryllus commodus

A functioning immune system is crucial for protection against disease and illness,yet increasing evidence suggests that species living in urban areas could be suffering from immune suppression,due to the presence of artificial light at night(ALAN).This study examined the effects of ecologically relevant levels of ALAN on three key measures of immune function(haemocyte concentration,lytic activity,and phenoloxidase activity)using a model invertebrate species,the Australian black field cricket,Teleogryllus commodus.We reared crickets under an ecologically relevant daily light‐cycle consisting of 12 hr bright daylight(2600 lx)followed by either 12 h darkness(0 lx)or dim environmentally relevant ALAN(1,10,100 lx),and then assessed immune function at multiple time points throughout adult life using haemolymph samples.We found that the presence of ALAN had a clear negative effect on haemocytes,while the effects on lytic activity and phenoloxidase activity were more complex or largely unaffected by ALAN.Furthermore,the effects of lifelong exposure to ALAN of 1 lx were comparable to those of 10 and 100 lx.Our data suggest that the effects of ALAN could be large and widespread,and such reductions in the core immune response of individuals will likely have greater consequences for fitness and survival under more malign conditions,such as those of the natural environment.