Quiet Night Research Articles

Estimating the drift velocity of plasma bubbles in airglow images using the scale invariant feature transform and the speeded up robust feature algorithms

Equatorial plasma bubbles (EPBs) are ionospheric irregularities that can significantly impact radio communication, causing signal scintillation that leads to signal loss and error in position calculations. In this study, we introduced a new technique to estimate the eastward and northward drift velocities of the EPB from ASI data by tracking the Scale Invariant Feature Transform (SIFT) and the Speeded Up Robust Features (SURF) points. The technique has been tested by studying multiple EPBs events detected over the Brazilian sector during the autumn equinox, spring equinox and summer solstice. The chosen events occurred during quiet nights (Kp index ≤ 3) and were observable through two All-Sky imager (ASI) stations. Moreover, the study shows the performance of the technique under different circumstances. It achieves optimal performance on clear-sky nights; however, cloud presence within the ASI field of view increases the error within the estimated values. The estimated velocities were found to be within the range reported by previous studies in the Brazilian sector.

A machine learning approach for estimating the drift velocities of equatorial plasma bubbles based on All-Sky Imager and GNSS observations

Equatorial Plasma Bubbles (EPBs) are zones characterized by fluctuations in plasma densities which form in the low-latitude ionosphere primarily during the post-sunset. They subject radio signals to amplitude and phase variabilities, affecting the functioning of technological systems that utilize the Global Navigation Satellite Systems (GNSS) signals for navigation. Thus, understanding EPB occurrence patterns and morphological features is vital for mitigating their effects. In this work, we employed two GNSS receivers and an All-Sky Imager (ASI) to conduct simultaneous observations on the morphology of EPBs over Brazil. The main objectives of the study were (1) to develop a Random Forest (RF) machine-learning model to estimate and predict the zonal drift velocities of EPBs, and (2) to compare the model predictions with actual EPB drifts inferred from the two instruments, as well as zonal neutral wind speeds obtained from the Horizontal Wind Model (HWM-14). In the model development, we utilized reliable EPB drift measurements made during geomagnetically quiet days between 2013 and 2017 in Brazil. The model predicted the velocities based on parameters including the day of the year, universal time, critical frequency of the F2 layer (foF2), solar and interplanetary indices. The correlation coefficients of 0.98 and 0.96 and RMSE values of 10.61 m/s and 10.06 m/s were obtained upon training and validation correspondingly. We evaluated the accuracy of the model in predicting EPB drifts on two geomagnetically quiet nights where an average correlation coefficient of 0.89 and an RMSE of 15.74 m/s were obtained. The predicted drifts, the zonal neutral wind velocities, and the GNSS and ASI velocity measurements were put into context for validation purposes. Overall, the velocities were comparable and ranged between ∼100 m/s and ∼30 m/s from the hours of 00 UT to 05 UT. The results confirmed the accuracy and applicability of the model, revealing the ionosphere-thermosphere coupling influence on the nocturnal propagation of EPBs under the full activation of the F region dynamo.

Exploring the link between convectively generated gravity waves and ionospheric anomalies: Insights from observations near the low-mid latitude geomagnetic transition region

In this paper, we examine the role of gravity waves (GWs) generated from tropospheric convection in initiating multiple nighttime ionospheric anomalies over Srinagar, located at 34.1°N, 74.8°E, and 25.91°N MLAT. Optical airglow observations during a geomagnetic quiet night (Ap = 4) of 29–30 June 2021, show the presence of plasma depletion tilted by an angle of ∼14.9° from the geographic North, quasi-periodic south eastward moving wave (QPSEMW), onset of two electrified MSTIDs and generation of plasma depletion channel between two MSTID phase fronts at ∼250 km altitude. GWs originating from deep convection in troposphere are detected at ∼85 and ∼97 km altitudes in OH and 557 nm filters respectively. The GWs in both the filters are propagating northward with almost similar characteristics. The intrinsic time period and vertical wavelength of GWs is estimated to be ∼11 min and ∼53 km respectively. We also present the observational indications of localised upliftment of F-layer ionosphere by ∼38 km, possibly initiated by polarization electric field generated through secondary GWs. The penetration of secondary GWs, generated by the dissipation of convective GWs, beyond the altitude of 500 km is also seen. FORMOSAT-7/COSMIC-2 RO data and SAMI3 model electron density suggest the occurrence of Sporadic-E (Es) layer at around 100 km altitude, caused by the negative gradient in eastward wind.

Is It Possible to Mitigate Fear of Fireworks in Dogs? A Study on the Behavioural and Physiological Effects of a Psychoactive Supplement.

Canine fear of fireworks is a common problem worldwide, with serious implications for the welfare of both dogs and their owners. Therapies for the problem are available, and herbal and nutraceutical agents are increasingly suggested by professionals; nonetheless, studies on their real efficacy in reducing firework fear are lacking. In a randomised, double-blinded, placebo-controlled study, 44 dogs (25 in the "supplement" group and 19 in the "placebo" group) completed a long-term continuous treatment with either a supplement made of tryptophan, valerian, and passiflora or a placebo, including two real exposures to fireworks (on 2020 Christmas and 2021 New Years' Eve, after 42 and 48 days of treatment, respectively). Owners of both groups received the same general environmental management and food/toy offering recommendations for trying with their dogs on those nights. Behavioural (measured by LSSS-Lincoln Sound Sensitivity Scale and PANAS-Positive and Negative Activation scale, as rated by the owners) and stress (measured via salivary cortisol measures) reactions were evaluated. Significantly greater fear decrease (LSSS) was recorded in the "supplement" dogs, as compared to the "placebo" group. Cortisol dosages on New Year's Eve ("noisy" night) were in line with behavioural results; "supplement" dogs showed a smaller increase in the stress response from 22:30 to 00:30 h on New Year's Eve and a greater decrease in their stress response from 02:30 h to 10:30 h on New Year's Day compared to "placebo" dogs. Smaller cortisol levels were also shown by "supplement" dogs than "placebo" dogs on a controlled "quiet night" (27th December). Owners' rates on PANAS remained stable during the whole period of therapy for both groups. The evaluated supplement, a combination of tryptophan, valerian, and passiflora, showed satisfactory results and rare side effects when treating dogs fearful of fireworks.

Drought triggers and sustains overnight fires in North America.

Overnight fires are emerging in North America with previously unknown drivers and implications. This notable phenomenon challenges the traditional understanding of the 'active day, quiet night' model of the diurnal fire cycle1-3 and current fire management practices4,5. Here we demonstrate that drought conditions promote overnight burning, which is a key mechanism fostering large active fires. We examined the hourly diurnal cycle of 23,557 fires and identified 1,095 overnight burning events (OBEs, each defined as a night when a fire burned through the night) in North America during 2017-2020 using geostationary satellite data and terrestrial fire records. A total of99% of OBEs were associated with large fires (>1,000 ha) and at least one OBE was identified in 20% of these large fires. OBEs were early onset after ignition and OBE frequency was positively correlated with fire size. Although warming is weakening the climatological barrier to night-time fires6, we found that the main driver of recent OBEs in large fires was the accumulated fuel dryness and availability (that is, drought conditions), which tended to lead to consecutive OBEs in a single wildfire for several days and even weeks. Critically, we show that daytime drought indicators can predict whether an OBE will occur the following night, which could facilitate early detection and management of night-time fires. We also observed increases in fire weather conditions conducive to OBEs over recentdecades, suggesting an accelerated disruption of the diurnal fire cycle.

Sleep disturbance in hospital – what can be done for a quiet night?

Sleep disturbance in hospital – what can be done for a quiet night?

On the quiet-time occurrence rates, severity and origin of L-band ionospheric scintillations observed from low-to-mid latitude sites located in Puerto Rico

In December 2021 three Global Navigation Satellite System (GNSS) ionospheric scintillation and Total Electron Content (TEC) monitors were installed in Puerto Rico (∼24.5° N dip latitude). The installation is part of an effort to better understand the occurrence of ionospheric irregularities and scintillation at mid-latitudes. Puerto Rico (PR) is commonly referred to as being located at mid-latitudes or at the boundary between low and mid-latitudes. Previous reports already presented observations of ionospheric irregularities and scintillation detected from PR. These observations, however, were limited in number. Additionally, the reports related the observed scintillation and irregularities events with different types of mid-latitude ionospheric disturbances. Here we present results from the analyses of the first three months of observations, December 21st, 2021 to March 20th, 2022. The analyses focus on the occurrence rate, severity and origin of scintillation detected on the signals tracked by the PR monitors during geomagnetically quiet times. We show that, out of the 43 geomagnetically quiet nights, 34 (∼80%) showed the occurrence of L-band scintillation. The results also indicate the recurrent existence of severe scintillation (S4 ∼ 1.0) accompanied by large TEC depletions. The temporal evolution of the observed scintillation showed that scintillation-causing plasma irregularities first occurred near the magnetic equator and propagated towards PR (reaching up to ∼22o dip latitude). Simultaneous space-based observations of the ionospheric F-region peak electron densities made by the GOLD mission confirmed that the quiet-time scintillation observed by the monitors in PR was associated with equatorial plasma bubbles. GOLD observations also show enhanced background F-region densities at the location of the Ionospheric Pierce Points of the affected GNSS signals, indicating conditions that favor the occurrence of intense scintillation.

A case study on multiple self-interactions of MSTID bands: New insights

In this study, we report a special event of nighttime southwestward propagating medium scale traveling ionospheric disturbances (MSTIDs) observed in O(1D) 630.0 nm airglow images from an all-sky imager at Hanle (32.7°N, 78.9°E; Mlat. ∼ 24.1°N), Leh Ladakh, India on a geomagnetically quiet (Ap = 7) night of 15 September 2018. The time sequence of airglow images unveiled two dynamic interactions between multiple dark bands of MSTID. Following the first interaction, one of the interacting bands decayed possibly due to the entrance of plasma from the ambient higher plasma density region. Shortly after this interaction, the other interacting dark band was involved in the second interaction with a third dark band which resulted in the co-alignment of the two interacting bands. Following this co-alignment, one of the bands started rotating prominently that led to further separation of these two co-aligned bands. These changes in the MSTID phase fronts (bands) are explained based on the development of the polarization electric fields arising out of the interactions. This investigation combines the all-sky 630.0 nm airglow imaging observations with TEC maps constructed, for the first time over the Indian sector, from 67 Global Navigation Satellite System (GNSS) measurements to capture the MSTID over this region. The investigation reveals a few important features of self-interactions of MSTID bands over the geomagnetic low-mid latitude transition region which is important to assess their impact over low latitudes.

Unusual simultaneous manifestation of three non-interacting mid-latitude ionospheric plasma structures

An unusual event of three characteristically different plasma structures on a geomagnetically quiet night (Ap = 4) of 08 July 2018 has been investigated in this paper using an all-sky imager installed at Hanle, Ladakh (32.7°N, 78.9°E; Mlat. ∼ 24.1°N), India. These structures include a freshly generated electrified medium scale traveling ionospheric disturbances (EMSTID), ambiguous plasma depletions, and a northward propagating non-electrified MSTID. One of the most fascinating aspects of this event was the lack of mutual interaction between the three structures, even though they existed simultaneously and propagated in different directions. They individually underwent evolution, distortion, and dissipation separately. One of the structures was an EMSTID, which got generated within the imager’s field-of-view (FOV) and evolved with time. As time progressed, different strip-like structures travelled southwestward, merged with each other to form the EMSTID. The second structure was plasma depletions which appeared in the southeastern part of the FOV. They eventually merged into a single band, which propagated nearly westward. The merged band evolved with time, extended further northward, and dissipated later. Along with these, a very rare non-electrified MSTID structure with east–west aligned fronts was observed which propagated northward. Its fronts underwent distortion, became curved and dissipated. In this study, we have explored the role of electrodynamics behind the observed unique features of the three plasma structures.

Assessing the impact of festival music on bat activity

Abstract Sound is a critical component of an animal's habitat, where it is used to glean important environmental information from their surroundings. The modification of natural soundscapes due to the global rise in anthropogenic noise pollution over recent decades can have serious negative impacts on species fitness and survival. Nocturnal species such as bats are reliant on sound for many aspects of their life history and are, therefore, highly sensitive to anthropogenic noise. Music festivals are a source of unregulated and potentially harmful, acute noise pollution; however, they have become ubiquitous across our landscapes throughout the summer months and are increasingly being held in settings important for wildlife. Using an experimental approach, we provide the first evidence of the negative impacts of music festivals on bat activity in a habitat that represents a typical festival setting, that is, woodland edge. We found that loud music playback alone can reduce the activity of bats even in the absence of other anthropogenic factors commonly associated with music festivals such as lighting and habitat disturbance. Activity of Nyctalus/Eptesicus spp. was reduced along woodland edge habitats exposed to loud music, whereas no effect was recorded for Myotis spp., Pipistrellus pygmaeus and Pipistrellus pipistrellus compared with quiet nights. We also provide the first evidence of the spatial scale of negative effects from festival music on activity for P. pygmaeus as well as highlighting differential responses between cryptic species. In light of the paucity of research or guidance into acute noise impacts on nocturnal biodiversity, we outline the potential negative impacts of music festivals for bats. We show that music alone can reduce the activity of bats even in the absence of other anthropogenic factors commonly associated with music festivals, which could potentially fragment important habitats for certain species, leading to a degradation of functional connectivity across the landscape.

Ways of Conveying the Aesthetic Value of Tang Poetry in Russian Translations: A Case Study of Three Translations of Li Bai’s Poem “Thoughts on a Quiet Night”

Russian and Chinese languages belong to different language families, which makes it difficult to translate from one language to the other. The translation of one poetic language into another without making any changes is an especially difficult task, which is why conveying the aesthetic value of the original poem becomes the embodiment of an ideal adequate translation. The aesthetic values of Tang poetry lie in the integration of sound, thought form and the poetic world, that is, in the beauty of rhythm, the accuracy of the line and the expression of feelings depicted in the text. Rhythm, rhyme and poetic dimension belong to the form of poetry; the meaning of words, sentences and text together form the meaning of poetry; and the picture of life depicted in the text makes up the poetic world. If the Russian translation of Tang poetry can achieve conformity of form, equivalence of meaning and consistency of the poetic world with the original poetry, then it will be able to realize the aesthetic value of the original poetry and will relate to the ideal complete translation of poetry. The poem “Thought on a Quiet Night” is one of Li Bai’s masterpieces and it is included in Chinese language textbooks for elementary school. Due to the high aesthetic value of this poem, it has become a compulsory poem for Chinese elementary school students to study. To date, there are eight translations of this poem in Russia. This article mainly considers the translations by V. A. Alekseev, L. N. Menshikov, and V. F. Pereleshin. Through the comparative analysis on these three versions about the “Thoughts on a Quiet Night”, it shows that different translators with different aesthetic aspirations may produce disparate translation.

A quiet place: The impact of the word "quiet" on clinical workload.

This study aimed to determine the impact of uttering the word "quiet" on clinical workload during the overnight otolaryngology call shift and understand the factors contributing to resident busyness. A multicenter, single-blind, randomized-controlled trial was conducted. A total of 80 overnight call shifts covered by a pool of 10 residents were randomized to the quiet or to the control group. At the start of shift, residents were asked to state aloud, "Today will be a quiet night" (quiet group) or "Today will be a good night" (control group). Clinical workload, as measured by number of consults, was the primary outcome. Secondary measures included number of sign-out tasks, unplanned inpatient and operating room visits, number of phone calls and hours of sleep, and self-perceived busyness. There was no difference in the number of total (P = 0.23), nonurgent (P = 0.18), and urgent (P = 0.18) consults. Tasks at signout, total phone calls, unplanned inpatient visits, and unplanned operating room visits did not differ between the control and quiet groups. While there were more unplanned operating room visits in the quiet group (29, 80.6%) compared to the control group (34, 94.4%), this was not found to be significant (P = 0.07). The majority of residents reported feeling "not busy" during control nights (18, 50.0%) compared to feeling "somewhat busy" during quiet nights (17, 47.2%; P = 0.42). Contrary to popular belief, there is no clear evidence that uttering the word "quiet" significantly increases clinical workload.

A Case Study on the Interaction Between MSTIDs' Fronts, Their Dissipation, and a Curious Case of MSTID's Rotation Over Geomagnetic Low‐Mid Latitude Transition Region

AbstractThis paper reports a rare interaction between two fronts of nighttime medium scale traveling ionospheric disturbances (MSTIDs) and associated phenomena observed over geomagnetic low‐mid latitude transition region on a geomagnetically quiet night (Ap = 5) of 21 May 2020. The event was observed for nearly 8 hours in O(1D) 630.0 nm airglow images captured by an all‐sky imager installed at Hanle (32.7°N, 78.9°E; Mlat. ∼24.1°N), Leh Ladakh, India and supplemented by a digisonde and a global positioning system receiver located within the imager's field of view (FOV). The images revealed a slow‐moving MSTID front being followed by a fast‐moving MSTID front, both traveling southwestward. The third front of the MSTID caught up with the second one, initiating the interaction. As a consequence, a plasma channel was created during the interaction and the MSTIDs' fronts began decaying. Subsequently, they became thin strips and later dissipated within the FOV of the imager. The polarization electric field of the merged region of the two interacting MSTIDs' fronts played a key role in creating the plasma channel. In the later hours of the night, another MSTID with a rotating front was observed, which is a rarely reported phenomenon. The horizontal gradient in the westward wind is a plausible reason for the observed rotation. This study elucidates the complex nature of geomagnetic low‐mid latitude transition region.

Multi‐Instrument Investigation of the Polar Holes

AbstractDuring the solar minimum the F‐region plasma density can become extremely low, and in some exceptional cases the F‐layer can completely disappear. These F‐region density depletions are particularly deep during geomagnetically quiet nights, when slow plasma convection creates polar holes, extending 100–1000 km in size, where the electron density is several orders of magnitude lower than the background values. Polar holes are believed to be formed during the periods of the very slow anti‐sunward convection, when the plasma is trapped just poleward of the auroral oval in the absence of any ionization sources. At the same time, fast convection with rapid vertical plasma transport has also been associated with the polar hole formation. Combining the electron density measurements from the Resolute Bay Incoherent Scatter Radar (RISR) and Poker Flat ISR (PFISR), the state of art variational data assimilation tool Ionospheric Data Assimilation Four‐Dimensional (IDA4D), and the convection data from the Super Dual Auroral Radar Network (SuperDARN) array, the polar hole formation and evolution are experimentally investigated. The F‐region plasma is traced back in time prior to the polar hole formation to analyze the favorable conditions for the formation of the polar holes. The role of plasma convection in the formation of the polar holes is experimentally investigated. The results show that the polar holes can be formed in the twilight condition and without being trapped in the closed convection loops. The formation of the polar holes were equally possible during slow and strong convection flows, predominantly with a standard two‐cell convection configuration.

Ionospheric Plasma Vertical Drift and Zonal Wind Variations Cause Unusual Evolution of EPBs During a Geomagnetically Quiet Night

AbstractPrevious studies show equatorial plasma bubbles (EPBs) mainly occur after sunset and usually drift from west to east. In this work, two EPBs occurred after midnight and lasted to sunrise, and were observed by multi‐instruments (two all‐sky imagers (ASIs), global positioning system, Swarm satellite, and a digisonde) during a geomagnetically quiet night of December 18–19, 2018. Our observations also show that plasma depletion structure (PDS) also occurred at that night. EPBs occurred in the region of PDS and showed a special evolution process during the night. Those PDS gradually disappeared with time, but strip‐like EPBs remained clearly in airglow images. Near sunrise, new PDS appeared to merge with those EPBs to form large PDS. Meanwhile, EPBs showed different zonal drifts within a very narrow longitudinal zone (∼2°). One EPB remained stationary while the other showed a small eastward drift. These results are different from post‐sunset EPBs in previous studies. During the lifetime of those ionospheric plasma irregularities, upward and downward motion of the peak height and virtual height of the ionospheric F region was observed by a digisonde, which indicates that the evolution of EPBs should be related to the vertical drift of ionospheric plasma. Besides, based Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model (TIE‐GCM) simulations, we suggest the different zonal drifts of those EPBs might related to plasma zonal drifts caused by zonal winds.

Observing electric field and neutral wind with EISCAT 3D

Abstract. Measurements of height-dependent electric field (E) and neutral wind (u) are important governing parameters of the Earth's upper atmosphere, which can be used to study, for example, how auroral currents close or how energy flows between the ionized and neutral constituents. The new EISCAT 3D (E3D) incoherent scatter radar will be able to measure a three-dimensional ion velocity vector (v) at each measurement point, which will allow less stringent prior assumptions about E and u to be made when estimating them from radar measurements. This study investigates the feasibility of estimating the three-dimensional electric field and neutral wind vectors along a magnetic field-aligned profile from E3D measurements, using the ion momentum equation and Maxwell's equations. The uncertainty of ion drift measurements is estimated for a time and height resolution of 5 s and 2 km. With the most favourable ionospheric conditions, the ion wind at E region peak can be measured with an accuracy of less than 1 m/s. In the worst case, during a geomagnetically quiet night, the uncertainty increases by a factor of around 10. The uncertainty of neutral wind and electric field estimates is found to be strongly dependent on the prior constraints imposed on them. In the lower E region, neutral wind estimates have a lower standard deviation than 10 m/s in the most favourable conditions. In such conditions, also the F region electric field can be estimated with uncertainty of about 1 mV/m. Simulated measurements of v are used to demonstrate the ability to resolve the field-aligned profile of E and u. However, they can only be determined well at the heights where they dominate the ion drift, that is above 125 km for E and below 115 km for u. At the other heights, the results are strongly dependent on the prior assumptions of smoothness.

Traffic noise-induced changes in wake-propensity measured with the Odds-Ratio Product (ORP)

Nocturnal traffic noise can disrupt sleep and impair physical and mental restoration, but classical sleep scoring techniques may not fully capture subtle yet clinically relevant alterations of sleep induced by noise. We used a validated continuous measure of sleep depth and quality based on automatic analysis of physiologic sleep data, termed Wake Propensity (WP), to investigate temporal changes of sleep in response to nocturnal noise events in 3-s epochs. Seventy-two healthy participants (mean age 40.3 years, range 18–71 years, 40 females, 32 males) slept for 11 nights in a laboratory, during which we measured sleep with polysomnography. In 8 nights, participants were exposed to 40, 80 or 120 road, rail and/or aircraft noise events with maximum noise levels of 45–65 dB LAS,max during 8-h sleep opportunities. We analyzed sleep macrostructure and event-related change of WP during noise exposure with linear mixed models. Nocturnal traffic noise led to event-related shifts towards wakefulness and less deep, more unstable sleep (increase in WP relative to pre-noise baseline ranging from +29.5% at 45 dB to +38.3% at 65 dB; type III effect p < 0.0001). Sleep depth decreased dynamically with increasing noise level, peaking when LAS,max was highest. This change in WP was stronger and occurred more quickly for events where the noise onset was more rapid (road and rail) compared to more gradually time-varying noise (aircraft). Sleep depth did not immediately recover to pre-noise WP, leading to decreased sleep stability across the night compared to quiet nights, which was greater with an increasing number of noise events (standardized β = 0.053, p = 0.003). Further, WP was more sensitive to noise than classical arousals. Results demonstrate the usefulness of WP as a measure of the effects of external stimuli on sleep, and show WP is a more sensitive measure of noise-induced sleep disruption than traditional methods of sleep analysis.

Evidence for the In‐Situ Generation of Plasma Depletion Structures Over the Transition Region of Geomagnetic Low‐Mid Latitude

AbstractOn a geomagnetic quiet night of October 29, 2018, we captured an observational evidence of the onset of dark band structures within the field‐of‐view of an all‐sky airglow imager operating at 630.0 nm over a geomagnetic low‐mid latitude transition region, Hanle, Leh Ladakh. Simultaneous ionosonde observations over New Delhi shows the occurrence of spread‐F in the ionograms. Additionally, virtual and peak height indicate vertical upliftment in the F layer altitude and reduction in the ionospheric peak frequency were also observed when the dark band pass through the ionosonde location. All these results confirmed that the observed depletions are indeed associated with ionospheric F region plasma irregularities. The rate of total electron content index (ROTI) indicates the absence of plasma bubble activities over the equatorial/low latitude region which confirms that the observed event is a mid‐latitude plasma depletion. Our calculations reveal that the growth time of the plasma depletion is ∼2 h if one considers only the Perkins instability mechanism. This is not consistent with the present observations as the plasma depletion developed within ∼25 min. By invoking possible Es layer instabilities and associated E‐F region coupling, we show that the growth rate increases roughly by an order of magnitude. This strongly suggests that the Cosgrove and Tsunoda mechanism may be simultaneously operational in this case. Furthermore, it is also suggested that reduced F region flux‐tube integrated conductivity in the southern part of onset region created conducive background conditions for the growth of the plasma depletion on this night.

Interaction between nighttime MSTID and mid-latitude field-aligned plasma depletion structure over the transition region of geomagnetic low-mid latitude: First results from Hanle, India

In this paper, we study the interaction between a nighttime Medium Scale Traveling Ionospheric Disturbance (MSTID) and geomagnetic north-south oriented field-aligned plasma depletion structure over Hanle, Leh Ladakh (32.7°N, 78.9°E; Mlat. ~24.1°N), India on a geomagnetically quiet night (06 May 2019, Ap = 4). The results are based on the observations carried out using a newly established airglow imager operating at 630.0 nm at Hanle which is a transition region of geomagnetic low-mid latitudes. A sequence of processes constituted this unique interaction that includes developing phase of the MSTID within the imager's field of view, gradual bending of the field-aligned plasma depletion structure and eventual merging with the MSTID, and propagation of the merged structure in the form of a single MSTID structure post-interaction. The mechanism appears to be controlled by unequal but oppositely directed polarization electric fields within the dark and bright bands of the developing MSTID, whose projection on the horizontal plane is observable in the airglow images. The present work is the first observation illustrating the interaction between a developing phase of MSTID and plasma depletion structure over a geomagnetic low-mid latitude transition region, which assumes importance for understanding the underlying plasma irregularity processes.

Combinations of Drinking Occasion Characteristics Associated with Units of Alcohol Consumed among British Adults: An Event-Level Decision Tree Modeling Study.

Alcohol consumption is influenced by the characteristics of drinking occasions, for example, location, timing, or the composition of the drinking group. However, the relative importance of occasion characteristics is not yet well understood. This study aims to identify which characteristics, and combinations of characteristics, are associated with units consumed within drinking occasions. It also tests whether accounting for occasion characteristics improves the prediction of consumption compared to using demographic information only. The data come from a cross-sectional, nationally representative, online market research survey. Our sample includes 18,409 British drinkers aged 18+who recorded the characteristics of 46,072 drinking occasions using 7-day retrospective drinking diaries in 2018. We used decision tree modeling and nested linear regression to predict units consumed in occasions using information on drinking location/venue, occasion timing, company, occasion type (e.g., a quiet night in), occasion motivation, drink type and packaging, food eaten and entertainment/ other activities during the occasion. We estimated models separately for 6 age-sex groups and controlled for usual drinking frequency, and social grade in nested linear regression models. Open Science Framework preregistration: https://osf.io/42epd. Our 6 final models accounted for between 55% and 71% of the variance in drinking occasion alcohol consumption. Beyond demographic characteristics (1 to 9%) and occasion duration (24 to 60%), further occasion characteristics and combinations of characteristics accounted for 31 to 70% of the total explained variance. The characteristics most strongly associated with heavy alcohol consumption were long occasion duration, drinking spirits as doubles, and drinking wine. Spirits were also consumed in light occasions, but as singles. This suggests that the serving size is an important differentiator of light and heavy occasions. Combinations of occasion duration and drink type are strongly predictive of alcohol consumption in adults' drinking occasions. Accounting for characteristics of drinking occasions, both individually and in combination, substantially improves the prediction of alcohol consumption.